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of Presentations and Posters of the International AIRR Conference, Oct. 1999, in Tbilisi, Georgia (Back) |
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of Presentations and Posters of the International AIRR Conference, Oct. 1999, in Tbilisi, Georgia (Back) |
Bufo
regularis, was examined by
topical application of a concentrated solution of prolactin to the
amputated
limb stumps of newly metamorphosed toadlets. This treatment resulted in
enhancement of regeneration; regenerative outgrowths of experimental
toadlets
were more frequent, larger in size and had improved morphology compared
to their control counterparts. All of the regenerates were hypomorphic,
consisting histologically of well-developed cartilaginous rods, caps or
collars, surrounded by connective tissue and skin. Rare or no muscle
development
was detected. We conclude that prolactin topically administrated in
concentrated
dosages, exerts a restricted positive effect on the regenerative
capacity
of Bufo regularis.
The tail of the
geckonid lizard,
Bunopus tuberculatus was amputated at a proximal level and the animals
were exposed to continuous darkness. The animals were intraperitoneally
injected, daily for 30 days postamputation, with prolactin. The
initiation
of regeneration, growth rate, as well as mitotic index of blastema
cells,
were enhanced by prolactin administration. Time required for
achievement
of regeneration phases in prolactin-treated lizards decreased compared
with control animals. It is concluded that prolactin may speed up the
rate
of tail regeneration in the geckos, and increases the mitotically
active
cell population during blastema formation.
EFFECT OF
ENDOGENEOUS NUCLEOLAR
TRANSCRIPTION FACTOR ON THE PROLIFERATING HEPATOCYTES.
T.Abramidze,
I.Kakhidze, D.Dzidziguri
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University
During last years we have been studying white rat hepatocytes nucleolar transcription factors. These are thermostable proteins with opposite (stimulatory and inhibitory) effects on transcription process. At present, it’s known that regulation of cell growth and proliferation is realized by growth factors, receptors, kinases and transcription factors, therefore we are interested how nucleolar transcription factors influence on proliferating cells in homological tissue. In particular, the effect of nucleolar protein fraction on transcription activity of regenerating and physiological growth hepatocytes was studied in vitro. It was determined that indicated fraction stimulates RNA-synthesis in both types of growing cells. At the same time, stimulating effect of nucleolar fraction is more intensive in regenerating hepatocytes that is probably connected with different amount of active ribosomal genes in these cells. Also, the effect of nucleolar protein fraction on mitotic activity of hepatocytes was investigated. It was shown that on the early stage of postnatal development after injection of nucleolar fraction the mitotic index of hepatocytes was decreased (in comparison with control by 40%). This fact may be explained by effect of inhibitory component of nucleolar protein fraction.
GRAVITY
INFLUENCES GROWTH AND DIFFERENTIATION
IN ADULT NEWTS
Hermann Josef Anton*,
Eleonora
N. Grigoryan**, Victor I. Mitashov**, Katja Krupp-Beyerlein*, Heike
Pitzer*
*Zoologisches Institut,
Universität
zu Köln, Weyertal 119, D-50923 Köln, Germany.
**Institute of
Developmental Biology,
Russian Academy of Sciences, 26, Vavilov str., 117808, Moscow, Russia
Life on
earth has developed under
the steady influence of gravity. All existing living systems up till
now
exist because of the very early gained ability to vanquish gravitation.
Since several years the
opportunity
exists to achieve microgravity (i.e. 10 – 5 to 10– 6 g) in space
shuttles
and stations. From our group experiments have been carried out first
with
adult newts (Pleurodeles Waltl) in space conditions. During the last 12
years regenerating newts lived in microgravity conditions aboard of the
Russian unmanned bio-satellites for time periods of 7 to 14 days
and have been investigated histo- and cytologically immediately after
return
to earth and later. All experiments brought the amazing results that
cell
physiology is influenced by microgravity. This is expressed by
increasing
the rate of cell proliferation within mitotic active tissues. In
connection
with that an earlier redifferentiation during regeneration processes in
all body parts which have been investigated till today (eye
lenses,
neural retina, limb, tail).
This acceleration takes
place not
only during the stay in weightlessness, but seems to outlast after
return
from flight under the normal earth gravity conditions. Up till now we
do
not know too much about the triggering phenomenon. We only know that a
7 to 14 days stay in weightlessness is followed by growth acceleration.
We also have proved
that simulation
of weightlessness by clinorotation has comparable results. But we don’t
know time and/or gravity threshold and the cytological switch on and
channeling
mechanisms too.
For more information
look at
presentations No: 
ANALYSIS OF THE
ACTIVITY OF KEY
GLYCOGEN METABOLISM ENZYMES AFTER A PARTIAL HEPATECTOMY OF NORMAL AND
CIRRHOTIC
RAT LIVER
N.N. Bezborodkina, M.V.
Kudryavtseva,
B.N. Kudryavtsev Institute of Cytology, Russ. Acad. Sci..,
S.-Peterburg
194064, Russia
For a long time it has been known about the possibility of involution of pathological alterations in the liver. However, studies on the effects of the resection of the cirrhotic liver on the restoration of its functional activity remained poorly. One of the key tissue-specific functions of the liver is the capability for synthesizing and degradating glycogen by the parenchima cells. A study was made of the activity of key enzymes of glycogenolyses and glycogenesis. Activities of glucose-6-phosphatase (G6Pase), glycogen phosphorylase (GP) and glycogensynthase (GS) were determined in the rat liver in norm, in the liver cirrhosis (CCl4-induced cirrhosis) and after a partial hepatectomy (PH). The enzyme activity in the liver punctates was determined by methods modified for small tissue samples. We have shown that activities of G6Pase and GP fell after the 6-month-long CCl4 poisoning to 36 and 40% respectively of the normal levels of these enzymes. After the PH the activity of G6Pase remained low at 3 and 6 months to only slightly higher than that in the cirrhotic liver. The activity of GP remained effectively as low as in the cirrhotic liver at 3 months, while further 3 months later it had reached the normal level. The activity of GS in the cirrhotic hepatic tissue did not differ from that in the normal liver, and no statistically significant changes in GS activity were revealed either during spontaneous recovery after the end of CCl4 poisoning or at 3 and 6 month after PH.
SKELETAL
MUSCLE REGENERATION IN
EXTREMELY OLD RATS
B.M. Carlson, A.B.
Borisov, E.
Dedkov, and J.A. Faulkner
Department of Anatomy
and Cell
Biology and Institute of Gerontology, University of Michigan, Ann
Arbor,
Michigan 48109, USA
Previous
experimentation with cross-age
muscle transplantation has shown that although extensor digitorum
longus
(EDL) muscles of 24-month old rats regenerate poorly in situ, they
regenerate
as well as young muscles if transplanted into the limbs of 4-month old
host rats. Subsequent experiments showed that in the absence of nerve
damage,
muscles in old rats damaged by exposure to Marcaine regenerated to
control
levels of function. Recent experiments have examined the regenerative
capacity
of muscles in extremely old rats (32-35 months old) that are near
death.
Although control muscles in these animals are weak and show a number of
morphological abnormalities, they nevertheless regenerated to control
levels
of function and higher than control mass 41 days after Marcaine
injection.
When EDL muscles from 32-month old rats were transplanted into legs of
young host rats, they regenerated as well as young-into-young EDL
muscle
transplants. These experiments show that even at a very advanced age,
when
the muscles show numerous aging changes, rat muscles still retain
sufficient
biological reserve to be able to regenerate well as young muscles in
vivo
if they are placed in a favorable environment.
(Supported by grant PO1
AG-10821
from the NIH.)
THE
CORRELATION OF NUCLEOLUS ORGANIZING
REGIONS QUANTITATIVE AND STRUCTURAL PARAMETERS (NUMBER, VOLUME,
3D-ORGANIZATION)
WITH CELL DIFFERENTIATION
*E.Cherkezia,
**O.Zatsepina, ***M.Gabrichidze,
***Sh.Jinjolia, *P.Tchelidze
*Group of Computed
3D-Engineering
of Biostructures and Tissues, Laboratory of Developmental Biology,
Department
of Biology and Medicine, Tbilisi State University;
**Department of
Electron Microscopy,
A.Belozersky Laboratory of Physico-Chemical Biology, Moscow State
University;
***Group of Computed
3D-Engineering
of Biostructures and Tissues, Kutaisi State University;
The
methods of ultrastructural computed
tomography and Ag-NOR-protein staining have been used for the virtual
3D-reconstruction
of metaphase nucleolus organizing regions (NORs) in intensively
proliferating
and differentiating erythroid cells, hepatocytes and endotheliocytes of
12-day old mouse embryos liver. It have been detected, that the process
of differentiation is accompanied by the decreasing of active
(Ag-positive)
NORs number and sizes probably due to the reducing of transcribing
ribosomal
genes “dose”. Such changes of mitotic NORs correlate with the
structural
and quantitative alterations of interphase nucleoli during
differentiation.
The material is
presented in the
form of computed animated film.
THE
POSSIBLE ORIGIN OF THE STROMAL
FIBROBLASTS IN THE PROCESS OF THE REGENERATION OF MOUSE CORNEA
K. Davitaia
Georgian Academy of
Sciences, Institute
of Zoology, Laboratory of Cytology, Tbilissi. Georgia
The origin
of white adult unlinear
mice eye corneal stromal cells after central perforating traumatisation
of Cornea with sterile preparating needle was investigated.
Histological studies
found out
that the new formation of stromal cells takes its origin from corneal
limb.
These cells are moving to the area of stroma wound already by 3 hours
after
operation. The entire epithelisation wound of cornea occures only on
5th
day, but stroma doused only on the 25-30th day after traumatisation.
The
autoradiographic
researches demonstrated, that regeneration of mechanically damaged mice
eye corneal srtoma cells mainly occurs due to predecessor cells,
intensively
multiplied and migrated throughout the limbal trabeculi to the corneal
stroma regeneration region.
With the help of
immunofluorescence
methods on the Xenogene chimere (rat-mouse) it was fixed, that
regeneration
of corneal stroma occurs by the fibroblasts, that take their origin
from
precursor cells, intensively proliferating beyond the borders of center
of inflammation possibly in the hematopoietic organs, may be in bone
marrow.
PROLIFERATIVE
ACTIVITY AND THE DYNAMICS
OF CELL DIVISIONS OF LYMPHOCYTES FROM PATIENTS WITH LUPUS AND RHEUMATOID
ARTHRITIS
N.A.Dvalishvili, N.N.
Sigua, T.A.
Lezhava Department of Genetics, Tbilisi State University, Georgia
Responses
of peripheral blood lymphocytes
to Phytohaemaglutinin (PHA) and cell rate divisions measured by
sister
chromatid differential staining have been studied in patients with
Systemic
Lupus Erythematosus (SLE) and Rheumatoid Arthritis (RA). In total 14
SLE
and 12 RA patients were investigated on blasttransformative activities
of lymphocytes in vitro. Lymphocyte cultures obtained from 10
phenotypically
healthy individuals served as control. All samples were cultured for 72
hr under the same conditions in medium not containing serum. Despite
the
wide variations among SLE patients in the blast index they revealed the
lowest values of indices. In 2 cases (chronic forms) cultures had the
indices
of response to the mitogen close to zero. The untreated RA patients
investigated
at an onset of desease showed significant increase of lymphocyte
transformation
patterns in vitro - in average of (84.6?0.81)% blasttransformed cells
compared
to (56.3?0.50)% in a control group, while the treated RA patients
revealed
dechne in response to PHA (an average index was (43.4?0.52%)).
Comparative evaluation
of cell
rate divisions revealed no significant differences in their values
between
the patients of the same groups. By the time of harvesting cell
populations
were asynchronous in all studied individuals. Character of the
distribu-tion
of cell divisions in case of RA was found to be considerably changed
with
a majority of the 2nd but with a rather high content of the 1st
division
cells (23.4% in comparison to 6.6% in control) suggesting a large
population
of cells with a delayed response to PHA. Dynamics of cell division for
SLE patients did not differ from control patterns.
G2
POPULATION OF HEPATOCYTES AND
LIVER REGENERATION IN WHITE RATS
D.V. Dzidziguri, Z.N.
Kokrashvili,
E.L. Mikadze, I. Modebadze, T.M. Shavlakadze
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University
After
partial hepatectomy the remnant
liver cells rapidly re-enter the cell cycle. Maximum mitotic activity
appears
by the 30th hour after the operation. Here we show that mitotic
activity
of hepatocytes is directly dependent on their RNA synthesis peak
obtained
6 hours after the operation. Today it is well known, that during 4
hours
after the partial hepatectomy expression of immediate early response
genes
takes place. Products of these genes, which represent transcription
factors
provide for the maximum level of the transcriptional activity of
delayed
early responce (ribosomal) genes 6 hours after the operation. Processes
connected with reparative growth are considerably changed in the
conditions
of hormonal disbalance. In the previous studies we have shown that in
the
adrenalectomized rats the first peak of transctiptional activity is
detected
3 hours after partial hepatectomy. Also it was demonstrated that 6
hours
after the operation mitotic activity of the hepatocytes increases,
which
was detected neither 4 days after adrenalectomy nor 6 hours after pure
hepatectomy. Our results indicate the existence of G2 population of
hepatocytes
in the liver tissues, as this is the only population to enter mitosis
within
6 hours after the operation.
We suggest that
adrenalectomy causes
accumulation of tetraploid cells during 4 days. However in order for
these
cells to enter mitosis, signal molecules are required, which activate
genes
regulators of cell growth. In the conditions of hormonal dibalance,
when
the cytostatic effect of cortisol is lost, a rapid expression of these
genes takes place. Therefore all processes that facilitate entrance of
the tetraploid hepatocytes into mitosis are being accelerated.
.
THE MECHANISM OF DAMAGE
REPAIR
AND IMMORTALITY OF MALIGNANT TUMOURS MAY INVOLVE THE EVOLUTIONARY
MEMORY
OF THE LIFE CYCLE OF UNICELLULAR ORGANISMS
Je. Erenpreisa*, M.
Cragg**, T.
Illidge**, Ivanov*
*Lab. Tum. Cell Biol.,
A. Kicherstein
Institute of Microbiology and Virology, Rige, Latvia;
**Lymphoma Lab.,
Tenovus Institute,
Southampon General Hospital, UK.
In multicellural organisms the cells are differentiated for somatic and germ ones, correspondingly mortal and immortal. Malignant tumours originated from mortal somatic tissues are immortal. Progression of tumours proceeding from benigh to malignant, which lasts for years, can be modelled by the response of the resistant p53 mutant tumours to damage, which is displayed in a few weeks. In our model system of p53 mutant human Burkitt’s lymphoma cell lines, treated by one dosage external beam irradiation 10Gy, the following set of responses was observed using DNA flow cytometry, radioautography, and cytology: (1) transent G2 arrest followed by a few aberrant mitoses ending in mitotic catastrophe; (2) polyploidisation during the 1st week followed by de-polyploidisation on the 2nd; (3) abundant apoptosis of 80-90% of polyploid cells; (4) restoration of diploid cell line during the 3rd week postirradiation. Subnuclear differentiation displaying different rates of DNA synthesis, as well as shedding of degraded chromatin from giant cells remaining alive themselves were found. The rest of the giant nucleus underwent a bouquet-like reconstruction strongly reminding a meiotic prophase. The polyploid bouquets then returned to interphase and radially splitted into secondary nuclei, which resumed mitotic cycle and constituated the recovered cell line. It is supposed that normally lethal dsDNAs, which arise from irradiation damage, are healed within giant cells in the meiotic-like prophase by recombination repair. The processes observed strongly remind the life cycle of heterokaryotic protists, however, pedokaryogamy was not observed, at least cytologically. The evolutionary mechanism, which involves a germ-like differentiation, provides both damage-resistance and immortality of tumours as theoretically predicted by Janis Erenpreiss (1992, 1993).
INFLUENCE
OF PLAFERON LB ON THE
TRANSCRIPTIONAL ACTIVITY OF REGENERATING LIVER AND KIDNEY CELLS
M.G.Gagua, D.V.
Dzidziguri, V.I.Bakhutashvili
Tbilisi State
University, Institute
of Medical Biotechnology, Georgia
Intricate modulatory role of several growth factors, main hormones and their intracellular secondary messengers remains poorly defined. Plaferon LB is a compound of biologically active substances produced from human amnion. A wide range of the pharmacological effects of Plaferon LB has been well studied. Here we show that the compound has an ability to regulate the transcriptional activity of the genes. Administration of Plaferon LB to adult white rats during 5 days leads to the considerable increase of the transcriptional activity of genes expressed in hepatocyte nuclei under the normal physiological conditions. Influence of Plaferon LB on the transcription of genes regulators of cell proliferation was studied on the regenerating liver model. Plaferon LB was administered by intraperitoneal injection to the experimental animals during five days and partial hepatectomy was performed. We have found that Plaferon LB effects transcriptional activity of genes involved in delayed early response. Particularly, 6 hours after the operation the RNA synthesis activity of liver cells increases by 30 per cent. It was also shown that 3-fold administration of the compound (1 hour prior to the operation, immediately after and 1 hour after the operation) results in the opposite effect. Six hours after the operation peak of transcriptional activity is inhibited by 46%. As it has well been established this peak of transcriptional activity in hepatocytes stimulated for proliferation is controlled by the expression products of immediate early genes and is directly related to the mitotic activity of hepatocytes. Similar results were obtained on kidney epithelial cells after unilateral nephrectomy. The obtained results indicate that Plaferon LB contains an active substance which has an ability to suppress the immediate early genes.
PARTIAL
SERUM REPLACEMENT BY ALKALOIDS
IN CULTURED FIBROBLASTS
M.Gedevanishvili,
N.Gogitidze,
M.Lebanidze, N.Malazonia and L.Tsutsunava
Inst.
Pharmacochemistry, 380059
Tbilisi, P.O.a/71, Georgia
Culture of the most cells requires the presence of serum. Presumably, serum contains mitogens generated during the coagulation process, e.g. PDGF and serotonin. Serotonin appeared to stimulate cell multiplication in vascular smooth muscle and certain fibroblast cell cultures by interacting with specific plasma membrane receptors [Gedevanishvili et al., 1978; Nemecek et al., 1986]. We have found also that alkaloids of Peganum harmala, Veratrum lobelianum and Vinca herbacea which mimic pharmacologycal effects of serotonin in isolated organ systems accelerate growth of the same fibroblast cultures (e.g. mouse and human embryo, L-929, L-197 and L41 cell lines).Moreover, in presence of serotonin or of these alkaloids it was possible to grow cells using 2.0-2.5 % of bovine serum instead of standard 10%. The cell multiplication promoting activity was apparent also when alcaloids were added to “starved” (quiescent) for 48 hr fibroblasts. In such cases effect of 0.5%-5.0 % serum plus alkaloids was equal to effect of 10% serum in resuming growth of cultures. Alkaloids, serotonin and serotoninergic receptor blocking agents - cyproheptadine, tipindole and inmecarb-iodine methylate were added to culture media at the moment of seeding, or 6 hr after seeding, and to 4-day cultures starved for 48 hr, in ?M (10-6-10-7 M) concentrations. Cell density and in special series, incorporation of [3H] Thymidine were determined. It is noticeable, that growth-resuming effect of 10% serum in starved cultures was completely abolished by inmecarb which is known to bind exclusively to cell surface. Also, serotonin (and, respectively, alcaloids) showed mitogenic activity at concentrations that are comparable to those found in human platelet-poor plasma. Finally, most investigators nowadays came to conclusion that an ideal culture system would contain only the defined components necessary for the survival, differentiation, or proliferation of the cell line [Wolfe et al., 1980]. Thus, the interaction among the many undefined components of serum and the cells in culture which can alter the biochemical and kinetic properties being investigated could be eliminated.
PHARMACOLOGY OF
GRANULOCYTE RESTITUTION
IN BONE MARROW-DEPRESSED HOST
M.Gedevanishvili,
A.Grkikian, N.Mushkiashvili
and Z. Tkabladze
Inst.
Pharmacochemistry, 380059
Tbilisi, P.O.a/71, Georgia
The role
of specific growth factors
defined as colony-stimulating factors (CSF) in the multiplication and
differentiation
of granulocyte cells is well established [Bessemer et al., 1986; Fagg,
1989; Hansen, 1997]. However, it is not clear whether another separate
group of steady-state regulators and long-range mediators of
generalized
hematopoietic response exists. In the present study effects of biogenic
amines and their functional analogues were investigated.
Alkaloid maidine,
epinephrine
and phenilephrine promote restitution of granulocytopoiesis in
X-irradiated
or myelotoxic drug treated animals. These substances promote also
granulocyte
colony formation on cellulose-acetate membranes inserted into the
peritoneal
cavity of irradiated host. Accelerated restitution of
granulocytopoiesis
was observed also under the influence of polyphenols, morphine,
pilocarpine
and Li-carbonate. Specific receptor-blocking agents which belong to
opiate,
cholinergic and alpha-adrenergic groups of pharmacological antagonists
eliminated granulocytopoietic effects, indicating that
granulocyte-restitution
promoters are active at different anatomical levels. The hypothesis is
advanced that cholinergic sympathetic vasolidator system and
subsequently
output of epinephrine is enhanced. According to this scheme
polyphenols,
morphine and lithium operate at hypothalamic and midbrain levels,
pilocarpine
activates cholinoceptors in adrenal medullary chromaffine
(postganglionic)
cell membranes, while epinephrine and alkaloid (maidine) stimulate
directly
the bone marrow hematopoietic elements by alpha-adrenergic mechanism.
However,
it is not clear whether epinephrine, and bioamine analogues explored,
act
upon granulocytic cells directly, or stimulate hematopoietic
microenvironment
to produce CSFs and/or related factors. If the cells of
granul-cytopoietic
lineage really possess adrenergic receptors, it would be of indubitable
interest to investigate consequences of cooperative action of
alpha-adrenergic
substances and CSFs in promoting granulo-cytopoietic differentiation
and
multiplication in stress conditions.
THE USING
OF NUCLEOLAR PARAMETERS
IN ESTIMATION OF WHITE RAT MYOCARD FUNCTIONAL STATE AFTER THE TREATMENT
WITH SPECIFIC GROWTH-INHIBITING CARDIOMYOCYTE FACTOR
N.Giorgobiani,
L.Rusishvili, D.Dzidziguri,
G.Tumanishvili
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University
There is
no doubt for the present
that the general morpho-functional characteristics of nucleolus are the
reliable exponent of functional state of tissue reflecting the
synthetical
and proliferative potencies of cells. The nucleolus is highly sensitive
to different kind of exo- and endogenious factors both of physical and
chemical nature. It is also well known that the nucleoli of dividing
cells
differ by their functional morphology from those of nondividing cells.
It has been determined that in the myocard of newborn animals the
proliferating
cells as well as differentiated cardiomyocytes are presented. For the
present
time there is no data on the "chalone"- type factors effect on the
ribosomal
genes transcription sites. Earlier we have extracted and described a
tissue-specific,
thermostable factor of white rat myocard ventricles, which inhibited
the
proliferation and DNA-synthesis in newborn rat cardiomyocytes and thus
can be referred as "chalone"-type factor. According to all mentioned
above
the possibility arose to observe the effect of our mitosis-inhibiting
factor
by means of nucleolar parameters.
For
purifying the obtained factor
the electrophoresis of its thermostable fractions has been carried out
and the eluates presented by low-molecular protein fraction (LPF) have
been collected. The objectives of our experiments were:I) the studying
of LBF effect on proliferative activity of 7-day newborn
rats
cardiomyocytes by means of colchicine mitotic index (MI); II) the using
of nucleolar parameters for estimation of 7-day rat myocard functional
state. For this purpose both paraffin and semi-thin sections were used.
It has been shown that MI of 7-day rats decreased by approximately 50%
after the treatment with LPF. On the semi-thin sections the nuclei with
active (3.6%), low active (21.2%) and inactive nucleoli (75.2%) were
counted.
After the treatment with LPF the number of cells with active and low
active
nucleoli decreased by approximately 40% and 47% correspondingly, while
the number of cells with inactive nucleoli increased by 40%. The
obtained
results showed that during the inhibition of proliferation the number
of
cells with inactive nucleoli increased, while the number of cells with
active nucleoli decreased.
THE EFFECT
OF GAMMA-IRRADIATION
ON INTENSITY OF REGENERATION DURING CALLUSOGENESIS OF HIGH PLANT
ORGANISMS
M.Gogebashvili
Georgian Scientific
Research Institute
ofAgricultural Radiology
The
forming of radiobiological response
during callusogenesis of high plant in many respects depends on
regeneration
intensity of meristemal tissues.
Thus, the
dedifferentiation of
tissues in injured callusogenesis zone is the basis of the realization
of the first processes. In this work the possibility of direct
influence
on regeneration intensity by gamma-irradiation and by this means the
regulation
of formbuilding processes in plant tissues is shown.
This fact can be used
in applied
aspect during the plant tissues transplantation and graft forming and
also
during regulation of totipotention response under conditions of tissues
cultivation in vitro.
The hypothesis of
principle of
hierarchical structural plant organization as basis of organisms
general
regeneration ability is advanced.
INFLUENCE
OF ETHANOL INTOXICATION
ON THE HYPOTHALAMUS DEVELOPMENT IN THE RATS’ OFFSPRING
Gvinadze N.N.,
Japaridze N.Dj.,
Svanidze I.K.
I.Beritashvili
Institute of Physiology,
Georgian Academy of Sciences, Tbilisi, 380060, L.Gotua 14. Georgia
Influence of 15% ethanol on the number of differentiating nervous cells was investigated in the rats hypothalamus preoptic, supraoptic, and nuclei of the mammilary bodies. Total of 17 nuclei were investigated on the 1st, 3rd, 7th, and 15th days of the postnatal ontogenesis. Statistically significant decrease of the nervous cells was found in the following nuclei: N.periventriculari hypothalamy (n.Pe), Area preoptica med. (MPO), Area lateralis hypothalamy (LPO), N.suprachiasmaticus (n.SCH), N.supraopticus hypothalamy (n.SO), N.paraventricularis hypothalamy (n.PA), N.mammilarius hypothalamy (n.MM), which shows different sensitivity of the neurons to ethanol and probably is a result of depression of their precursor cells proliferation and migration.
STUDY OF
MOLECULAR EVENTS WHICH
TRIGGER LIVER REGENERATION
Z.N. Kokrashvili, T.M.
Shavlakadze,
I.Modebadze, I.G. Kakhidze, M.G. Gurushidze, D.V. Dzidziguri
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University Georgia
Previously we have shown that under the conditions of hormonal disbalance, the hepatocytes stimulated for proliferation exhibit accelerated expression of genes regulators of the cell growth. The first peak of transcriptional activity emerges three hours after the partial removal of the liver tissue and is further followed by early mitosis (6 hours after the operation). We suggested that in the destructive liver tissue the increase of mitotic index should be due to G2 (possibly tetraploid) hepatocyte population. Entrance of these cells into mitosis should have been a result of the accelerated expression of the immediate and delayed early response genes. It is now known that the expression products of immediate early genes (which include foc and jun proto-oncogenes) induce the subsequent activation of delayed early genes. To suppress the activation of early response genes we used their well known inhibitor Doxorubicin (DOX) and also Cortisol. DOX, Cortisol and DOX+Cortisol was administered to intact white rats prior to partial hepatectomy, immediately after the operations and 1 hour after the operation. Transcriptional activity of hepatocyte nuclei was studied 6 hours after the operation. It was shown that separate injections of DOX and Cortisol as well as their combined administration results in almost two fold inhibition of RNA synthesis activity in hepatocytes. The obtained results suggested that the suppression of immediate early genes by cortisol, which is similar to that by DOX causes inhibition of delayed early gene expression. In the following seria of the experiments we showed that in the conditions of hormonal disbalance the intensity of transcriptional activity of the hepatocyte nuclei stimulated for proliferation is directly related to the level of mytotic index. Higher the transcriptional activity is, higher the is the mytotic index of the hepatocytes 6 hours after the operation. These results proved our suggestion that transition of G2 hepatocytes into mytosis is due to the activation of delayed early genes three hours after the operation.
THE
AUTOREGULATION OF THE NUMBER
OF UNICELLULARS IN CULTURE
A.A.Kozlov
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University, Georgia
The hypothesis has been
made that
the sizes of organs in embryogenesis, postnatal development and during
reparative growth is controled by the mechanism formed on the earliest
stages of evolution on the level of unicellular organisms assemblies.
The
experiments on Colpoda sp. have shown, that such mechanism limiting the
whole number of cells in culture independently from the volume of
culturing
does work in the culture of these protozoans.
It have been confirmed
that the
explanation of the observed effects requires the involvement of
physical
mechanism of the transmission of information on the whole number of
cells
in culture to every single cell.
The variant of such a
physical
mechanism is discussed. The comparison of experiment and theoretical
data
is presented.
GLYCOGEN-FORMING
FUNCTION OF HEPATOCYTES
AT REGENERATION AFTER A PARTIAL HEPATECTOMY OF NORMAL AND CIRRHOTIC
LIVER
Kudryavtseva M.V.,
Bezborodkina
N.N., Kudravtsev B.N.
Institute of Cytology,
Russian
Academy of Sciences, S.-Peterburg 194064, Russia
Regeneration
is both actual biological
and medical problem. Studies of the regeneration process was made
primary
on the normal liver. However, for medicine it means significant the
possibility
of involution of pathological alterations in the liver. Morphological
and
functional investigations of the mammalian liver regeneration found
significant
regenerating possibility of this organ, promoting of involution
cirrhotic
alterations. This fact may be of the experimental substantiation for
use
of resection in clinic. Experimentally, there are detailed studies on
the
effects of the resection of the cirrhoric liver on the recovery of the
liver morphological structure. Meanwhile, the recovery of the
functional
activity of the liver parenchyma cells has so far remained poorly
studied.
Using cytofluorimetric method the content of total glycogen (TG) and
its
labile (LF) and stable (SF) fractions were determined in isolated
hepatocytes
in norm, in the liver cirrhosis and during regeneration after a partial
hepatectomy (PH) of the normal and cirrhotic liver. The liver cirrhosis
was shown to be characterised by a 2-3-fold increase in the total
glycogen
content and to a similar increase in the LF content. Even more
pronounced
(4.6 times) was the SF accumulation in the cirrhotic liver cells. By 6
month after the PH of the cirrhotic liver, the TG and its fractions had
completely returned to normal.
DIFFERENT REACTION OF THE BIRDS
EYE RUDIMENT CELLS
ON THE INFLUENCE OF
Act-D UPON
DEPENDENCE OF ITS STAGE OF DEVELOPMENT
G. Kvinikhidze
Georgian Academy of
Sciences, Institute
of Zoology, Laboratory of Cytology, Tbilisi, Georgia
Vertebrates eye is a convenient model to study the process of differentiation, as it consists of many different types and origin cells. In previous work we had shown, that the differentiation of eye rudiment cells (retina and lens cells) is realized in accurate temporal and special interrelation between the processes of specific synthesis, proliferation, cytochemical and specific ultrastructural organization of cells. Moreover, the termination of these processes is realized only after visualization of cells ultrastructural and cytochemical peculiarities of retina and lens rudiment cells. Thus, we decided to study how much inhibition of cells transcriptional activity influence on the process of these rudiments cells differentiation. For that aim Actinomicin D (Act D) was endued (1? on 1g of weight) in different stage of development chick embryos. Material was fixed after 20m, 1, 3 and 24 hours after the enduetion of the inhibitor. Concentration of RNA and common protein in cells was measured by quantitatively cytophotometrical methods on the zond photometer “Zetopon” (Reichert) and on the “Microvideomat-2” (Option). The proliferation activity of the cells was examined by enduing labeled 3H-thymidine in the egg. The ultrastructure of the cells was studied in the transmittional electron microscope (IEM-100). Date figures were processed statistically. Results of investigation showed, that inhibition of the transcription of Act-D causes the rapid decrease of the concentration of RNA and common protein, especially considerable in the first days of incubation (1 - 12 days of inc.). The decrease of the concentration of RNA and common protein is shown in the cells ultrastructure. Simultaneously the proliferation activity of cells decreases. Together these changes on the early stage of development (1-2, 3-4 days of incubation) cause the inhibition of development and sometimes the embryos death. 24-hour incubation of 6 and 7 days embryos with Act-D causes delay formation of the second lens fibers and appearance of abnormal, vacuolated lens. The inhibition in formation of membrane disks of the outer segments of the cones (photoreceptors of the retina) of 10-11 days embryos at 24 hours incubation with the Act-D, is registered as well. The results show, that transcription of mRNA for the membrane disks protein (opsin) are occurring just from 10 to 11 days of incubation Before hatching (17-19 days of incubation) in inhibitory influence of Act-D is observed only in first hours of incubation with an inhibitor. These results of the undertaken experiment show that the inhibition of transcription by Act-D causes different reaction in rudiment retina and lens cells of chick embryos in dependence of stage of development and grade of cells differentiation. It was supposed that significant inhibition effect of Act-D occurs in eye rudiment cells in period of active transcription of mRNP for specific structure proteins (Lens erystallins and cone photoreceptors-opsin).
POSSIBLE
ROLE OF APOPTOSIS IN THE
PROCESS OF RAT LIVER REGENERATION
Mikadze E.L.,
Mamatsashvili T.G.
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University, Georgia
The liver
of hepatectomized rats
in norm and under the effect of chloramphenicol was studied at
different
period of time after the operation; the degree of inclusion of 3H-
thymidine
into the nuclei of hepatocytes on the 22 hour after the organ resection
and the transcriptional activity of the nuclei of hepatocytes before
hepatectomy
were investigated as well.
Apoptotic cells in
normal regenerative
liver were observed on the 6-10 hour after the operation, but they were
not observed in the hepatectomized rat liver under the effect of
chloramphenicol.
The inclusion of 3H-thymidine into the nuclei of hepatocytes of
experimental
rats was inhibited by 46% compared to control, whereas the indications
of transcriptional activity of nuclei of hepatocytes in both groups
before
the operation were equal within the limits of mistake.
On the basis of the
analysis of
the obtained data we supposed that the origination of apoptotic cell
population
is due to a loss of cell mass as a result of 1/3 organ resection, and
that
just the existence of apoptotic cells contributes to normal liver
regeneration.
Absence of population of apoptotic cells in the rat liver under the
effect
of chloramphenicol, directly connected with the inhibition of
mitochondrial
function, leads to the decrease of inclusion of 3H-thymidine into the
nuclei
of hepatocytes, i.e. to a partial block of S-phase. Equal values of
transcriptional
activity of the nuclei of hepatocytes in both groups of rats at the
moment
of operation suggest that the activation of chloramphenicol
effect
causing the inhibition of apoptosis and decreasing the degree of
inclusion
of 3H- thymidine into the nuclei of hepatocytes of experimental rats is
caused by the intensification processes in the cells and tissue of
liver
immediately after the operation.
The obtained results
led us to
the suggestion that the apoptotic cell population should contain
substances,
which facilitate the undamaged hepatocytes to enter a new cell cycle.
The
obtained data to a certain extent are in agreement with our earlier
suppositions
according to which in the process of programmed cell death the cell
produces
substances that can enable it to survive, but at the irreversible DNA
degradation
these substances, no longer important for this cell, can stimulate
neighboring
cell division.
We suggest that
“altruism” of apoptotic
cell is in its capacity to affect intact cells of the tissue when dying
as mitogenic or growth factor and thereby regulate the cell balance of
tissue.
THE
HYPOTHETICAL MODEL OF THE POLYPLOIDIZATION
OF RAT LIVER HEPATOCYTES
Mikadze E.L., Berulava
M.N. Tumanishvili
G.D.
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University,Georgia
In the liver tissue both of embryonic and postnatal (in norm and after hepatectomy) rats the “bimitosis” - a main stage of the hepatocyte polyploidization model, dominating in the literature, was not observed, but in the pair of cells located quite close to each other synchronous mitosis were detected. On the grounds of our own as well as literary data, the scheme of synchronous mitosis formation was drawn up. This scheme, in certain aspect, is able to reflect the stages of hepatocyte polyploidization as well. At the 1st stage the diploid hepatocyte, as a result of acytokinetical mitosis, conditioned by the defect of cytotomy, forms a binuclear hepatocyte. At the 2nd stage the nuclei of binuclear hepatocyte synchronously pass G1 and S phases, that results in a forming of binuclear tetraploid. At the 3rd stage the binuclear tetraploid, due to the apoptotic cells excrescences undergoes cytokinesis and forms two monotetraploids. At the 4th stage the cells start mitosis as a result of which, in our opinion, not 4 mononuclear, but 2 binuclear diploid cells are formed. Therefore, at each stage of the process of synchronous mitosis, during a certain period of time, hepatocytes of various classes of ploidity are present. Since synchronous mitosis, the amount of which increases with the age of embryo, are formed as a result of violation of normal flow of mitosis, in the light of conception of cell mortality and the limited number of cell duplications, we may assume that synchronous mitosis are indicating the stage of the cell, and their rise is connected with the certain critical number of cell duplications. Further cell duplications and conformable shortening of telomeric segments of chromosome, as is well known, threaten the cell with the death. Due to this reason we think that in a response to the next external proliferative stimulus, the cell changes its mitotic cycle and the process of formation of synchronous mitosis is being blocked at some stage. The blocked cells start to differentiate and then to function, enriching the liver tissue with the hepatocytes of different classes of ploidity. Proceeding from mentioned above, we consider that the importance of ploidity is mainly the conservation of the vitality of the cell, its survival and is directed towards the defense of the cells from further divisions, and possible duplication, at the same time is limited by the duplication of its genetic material.
3D-MODELLING
OF THE STRUCTURE AND
FUNCTIONAL CHANGES IN RENAL TUBULAR EPITHELIUM DURING ADAPTIVE GROWTH
E.Mishatkina,
G.Tumanishvili, P.Tchelidze
The Group of Computed
3D-Engineering
of Biostructures and Tissues, Laboratory of Developmental
Biology,
I.Javakhishvili Tbilisi State University, Georgia
Earlier the striking functional heterogeneity of mice nephron proximal epithelium have been demonstrated, though, the whole range of questions remain unknown: 1) whether the shown functional polymorphism of mouse kidney epithelium is characteristic for all the mammalians; 2) whether such a polymorphism presents in nephron distal region as well. The objectives of the present study was to find out the character of functionally active cells distribution within the proximal and distal regions of nephron. It have been shown that: 1) white rats are also characterized with the functional polymorphism; 2) such functional polymorphism with the specific features presents also in distal region of nephron. The obtained results let us to suggest the presence of mechanisms regulating the activation of cells throughout the nephron.
CHANGES IN
PROTEIN KINASE C (PKC)
ACTIVITY AND ISOFORMS EXPRESSION DURING REGENERATION OF EDL AND SOLEUS
RAT MUSCLES
Moraczewski,J.,*
Nowotniak,A,.*
Castagna M.,**Gautron,J.,*** Martelly,I.*
*University of Warsaw,
Faculty
of Biology, Department of Cytology,
Krakowskie Przedmieocie
26/28,
00-927 Warsaw, Poland
**INSERM, Oncogenese
Applique,
94807 Villejuif ,France
***University Paris
XII, Faculty
of Science and Technology, Laboratory CRRET, 94010 Creteil, France
An in vivo model of crush-induced EDL and Soleus muscle regeneration in rat was used to study changes in protein PKC during the regeneration process. In this model, EDL muscle regenerates more rapidly than Soleus muscle and that has been associated with the level of mRNA expression of PKC isoforms as determinated by PCR. PKC activity was reduced by half in both muscles during the first 3 days following crushing, in the myolysis step. Then this activity highly increased in EDL muscle at day 7, in the recovering step of muscle fibers, then down to the contralateral levels at day 14 of regeneration. In Soleus muscle PKC activity was increased only at day 14. Surprisingly, PKC activity was transiently increased in both contralateral muscles. As shown by Western blotting technique, PKC isoforms alfa, epsilon, theta, delta, then beta, eta and finally zeta and iota/lambda were sequentially expressed in regenerating muscles. PKC isoforms alfa, theta, epsilon, zeta were immunolocalized in fibers as well as in surrounding tissue in regenerating muscles. These studies support the possibility that PKC isoforms fulfil different functions in muscle regeneration.
DIFFERENTIATION
OF CELLS IN SPINAL
CORD AND SKELETAL MUSCLE EXPLANTS DURING THEIR SIMULTANEOUS CULTIVATION
D.P. Museridze, I.K.
Svanidze,
Ts.S. Tsaishvili
I. Beritashvili
Institute of Physiology,
Georgian Academy of Sciences, Tbilisi 380060, L. Gotua, 14.Georgia
Processes
of histogenesis in vitro
proceeds most completely during concomitant cultivation of tissue
forming
a unitary functional system in vivo. We have studied ultrastructural
peculiarities
of the spinal cord neural cells and the somatic muscle cells of 14 days
old chick embryos after simultaneous cultivation.
The data obtained
indicate that
adaptation processes are completed within the first days of
cultivation.
Further cultivation leads to the differentiation of neurons and
intensive
growth of motoneuron axons toward the muscle tissue.
The present work shows
that during
simultaneous cultivation of somatic muscle tissue and spinal cord
explants
the vasic stages of differentiation, necessary to restore functional
contacts
between motoneurons and muscle tissue in vivo, are remained.
HOW THE
REPARATIVE GROWTH SCENARIO
EVOLVES DURING LIVER DEVELOPMENT?
T.M. Shavlakadze, I.R.
Modebadze,
Z.N. Kokrashvili, E.J.Tavdishvili, M.G. Gurushidze, D.V.Dzidziguri
Laboratory of
Developmental Biology,
Department of Biology and Medicine, Tbilisi State University. Georgia
The adult
rat liver regeneration
following the partial hepatectomy is a physiologic response to a
growth stimulus. Restoration of the removed portion of the tissue
starts
with a rapid activation of early response genes (proto-oncogenes) and
thereby
with the establishment of a transcriptional cascade. Not
much
is known about proto-oncogenes which regulate hepatocyte growth
in
the developing liver. Mostly, regulatory role of c-jun and c-met and
expression
of a number of liver specific genes is revealed. Also, expression of
growth
and transcription factors during fetal and neonatal development is now
intensively studied. However, the exact mechanisms by which the
proliferative
growth response to injury may be evolved in the developing liver are
unclear.
We studied the
transcriptional
activity of hepatocyte nuclei in normal one month old rats and
after
partial hepatectomy. Rhythmic changes of RNA synthesis activity
of
growing liver cell nuclei was observed in 10 hour period (from 10 am to
8 pm). Also we showed that during the first 10 hours after the partial
hepatectomy transcriptional activity of hepatocyte nuclei peaks twice,
after 2 and 5 hours. We suggested that the first peak of
transcriptional
activity should be due to the expression of immediately early response
genes (e.g. c-jun). To reveal the mechanism involved in the
transcriptional
activation of one month old rat hepatocytes in response to the partial
hepatectomy, we used suppressers of genes regulators of cell
proliferation-
Doxorubicin and Cortisol.
Based on the
obtained
results we suggest a pivot role of genes independently suppressed
by Doxorubicin and Cortisol for the realisation of the reparative
growth program in the developing liver. After one month old rat
hepatocytes
receive stimulus for the reparative growth, transcriptional activity of
these genes increases and peaks after 2 hours.
NEW
STRUCTURES IN RENEWING NEWT
TISSUES
Charles Taban
59b. ch.Falquets,
CH-1223 Cologny.
Unexpected structures forming meshes and most probably constituted by cell glycocalices interconnections were detected in the newt by application to cryostat sections of gold markers (Taban, 95) recognizing specific binding sites to substance P. dophamin, nor-adrenalin and serotonin. These structures were restricted to newt limb regenerates and in adult tissues, which are rapidly and constantly reconstituted, such as epidermis. In this last the mesh appears at mid-distance between the basal cell layer and the external surface, that is at a completely different site than the adepidermal membrane. The limb amputation trauma destroys these structures which are reconstituted during the regenerating process. It has been shown by A.Schmidt that this trauma destroys similarly the glycocalices ordinance, sustaining the view that the meshes seen with the gold marker include glycocalices. These results bring 1) a new evidence that several different neurotransmitters can bind the tissues of the regenerate; 2) show that groups of growing and differentiating cells of the regenerate have the possibility to react simultaneously since they are correlated directly by cell extensions. Studies carried out by others and visualizing collagenes, fibronectin or laminin in the newt did not see the described meshes. Current studies attempting to define the chemical components of the meshes are in progress.
POU-DOMAIN
OCTAMER-BINDING TRANSCRIPTION
FACTORS. DIFFERENTIAL EXPRESSION OF THE OCT3/4 DURING MOUSE
SPERMATOGENESIS.
A.N.Tomilin,
*G.-E.Seralini, *M.A.Drosdowsky,
V.I.Vorob’ev,
Institute of Cytology,
Russian
Academy of Sciences, 194064, St.Petersburg, Russia. *Université
de Caen, 14032 Caen, France
Molecular
cloning of mammalian transcription
factors Pit1, Oct1, Oct2, and nematode developmental regulatory protein
Unc-86, revealed that all they had a common sequence referred to as the
POU-domain, which recognizes the DNA octamer sequence (ATGCAAAT).
Octamer
motif required for both ubiquitous and tissue-specific expression of
various
genes. Oct1 was present in all cell types tested, while Oct2 was
detected
only in immunogenic cells.
The POU-domain
octamer-binding
transcription factor Oct3/4 is thought to be involved in maintaining of
pluripotency of embryonal cells and to play a central role in
establishment
and maintenance of the germline in mammals. Using in situ
hybridization,
RT-PCR, immunofluorescence and Southwestern approaches we have found
recently
that in addition to the early pluripotent cells, primordial germ cells,
and oocytes, the Oct3/4 protein is expressed in a stage-specific manner
during spermatogenesis, being predominant throughout meiotic phase. The
data obtained allow to suggest that Oct3/4 may exert regulatory
function
in the control of meiotic events and terminal differentiation during
spermatogenesis.
A series of data
indicate that
Oct3/4 protein can activate transcription only in cooperation with
cellular
coactivator molecules through protein-protein interactions, and that
these
hypothetical proteins are functionally related to the adenovirus E1A
protein.
Attempts to isolate putative Oct3/4 coactivators by affinity methods
have
failed. We have used a bacterially produced recombinant mouse Oct3/4
(rOct3/4),
as a protein-binding probe, to detect by far-Western assay the
Oct3/4-associating
proteins (OTAPs). Nuclear proteins extracted from pachytene
spermatocytes,
from embryonal carcinoma (EC) cells F9 and from the same cells after
retinoic
acid-induced differentiation were separated by SDS-PAGE, transferred
onto
nitrocellulose, and filters was probed with labelled rOct3/4. Both
common
and cell specific OTAPs were shown to interact directly with Oct3/4.
Several
OTAPs detected in pachytene spermatocyte may represent germ
cell-specific
Oct3/4 coactivators. Differentiation of the EC cells results in
disappearance
of most of OTAPs, supporting their coactivator nature. (Supported
by the Russian Basic Research Foundation).
PROLIFERATION
AND DIFFERNTIATION
CAPACITY OF RAT LATERAL VENTRICLE CELLS IN EMBRIONAL AND EARLY POSNATAL
STAGES AFTER THEIR TRANSPLANTATION INTO NEOCORTEX OF ADULT RATS.
P.D. Bukia, U.G.
Kharebava, E.Y.
Kalandarishvili, A.D. Taktakishvili; M.T. Davitashvili, N.Sh.
Gelashvili,
Mepisashvili I.A.
Problematic
morpho-physiological
laboratory of Tbilisi State University, Georgia
The aim of
the present investigation
is to study the development and growth dynamic of germinative cells of
dorsolateral wall of lateral ventricle transplanted from donors with
different
age.
The study was performed
on white
rats. We used 16, 17, 18, 20 days old embrions and 1,2,3,4,5 days old
small
rats as donors. Peaces of matrix (1 -1,5 mm2) of dorsolateral wall were
implanted into the neocortex of adult rats.Recepients were decapitated
on on different time points post transplantation. In particular, the
material
was obtaind from 2 days to 6 months post transplantation. The obtained
material was treated for neuro-histological investigation.
The direct dependency
of transplant
lodge, growth and differentiation on the age of donor has been
established.
The growth and development of the transplant is the most successful
when
it is obtained from embrio, especially from 16 - 17 days old
embrional
matrix. Thus, 2 weeks after transplantation, 17 days old
embrional
germinative cells actively proliferate, the transplant grows
significantly
and consists of poorly differentiated, densly packed elements. Several
structural specifities of the transplant makes it easy to identify it
from
the surrounding tissues of the recepient neocortex. These are the
chain of glial cells on the edge, sizes of the neural cells,
disorientation
of cell bodies and their cytoplasmic branche, absene of normal
cytoarchitecture.
The level of lodging and integration of newborn donors matrix with
surrounding
tissues and proliferation of cellular elements is less pronounced
than in transplants from embrional matrix at the same
postimplantational
time points.
Thus, based on the
obtained results
we suggest that after implantation of newborn rat matrix, precursors of
neurons lodge, grow, differentiate and establish contacts with neural
tissue
of recepient. However, this process is lesser pronounces then in case
of
implantation of embrional matrix.
ribosomal genes in
these cells.
Also, the effect of nucleolar protein fraction on mitotic activity of
hepatocytes
was investigated. It was shown that on the early stage of postnatal
development
after injection of nucleolar fraction the mitotic index of hepatocytes
was decreased (in comparison with control by 40%). This fact may be
explained
by effect of inhibitory component of nucleolar protein fraction.