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PubMed1976

Modifications in some rat liver cell components following stimulation with isoprenaline (a cytospectrophotometric, microrefractometric and cytoelectrophoretic study).

The liver cell is a quite interesting model for the study of several cytophysiological problems. Proper suspensions of isolated liver cells can be obtained which can be conveniently studied by means of quantitative microtechniques. Several cytochemical and cytophysical techniques (cytospectrophotometry, microrefractometry, and cytoelectrophoresis) were employed for elucidating the effects on the stimulation of the liver cell with high doses of isoprenaline, an amine which is known to produce hypertrophy and hyperplasia in various organs with effects also at the genetic and metabolic level. The following data were collected during the postnatal development of rats up to the 70th day of life: 1) DNA content per nucleus; 2) total dry mass per cell; 3) cellular electrophoretic mobility in connection with the sialomucinic component of the membrane. The process of polyploidization of the liver cell (typical of this life period) was generally accelerated; in this connection, an early appearance of binucleate cells and subsequent significative variations in their incidence were observed. This fact is important as the binucleate cells should represent an alternative intermediate step in the polyploidization phenomenon. At the same time, marked, although transient, signs of cellular hypertrophy were detected during a rearrangement of the hepatocyte dry mass, where the values tended to a multimodal distribution; in particular, IPR appeared to favor the disappearance of cells with a lower mass to the advantage of those with an intermediate mass. The study of electrophoretic mobility evidenced the role of the sialomucinic component of the membrane in the changes occuring in the parenchyma: indeed, this component exhibited an increase, thus causing an acceleration of the mobility similar to the one observed in actively proliferating cell populations. Such change persists even long after the IPR stimulus has ended and, at any rate, beyond the immediate phase of DNA synthesis and the appearance of binucleate cells.

Animals↗
PubMed2000

[The effect of mycoplasmal contamination of human embryonic lung cell line MRC-5 on the karyotypic variability].

Karyotypic variability has been investigated for nonimmortalized human embryonic lung cell line MRC-5, cultivated with Acholeplasma laidlawii strain PG-8 for 15-45 days. The character of cell distribution for chromosome number did not change during this time. In all investigated variants the number of polyploid cells increased considerably with the lengthening of the term after decryoconservation. The number of chromosomal aberrations in 15-45 days contaminated cells increased significantly as compared to the control at the expense of dicentrics (telomeric associations). The number of dicentrics had a tendency to increase with the lengthening of the term of contamination. Thus, in 45 days the number of dicentrics increased twice as much as that in 15 days. The increase of polyploids may be due presumably to the specific character of karyotypic variability in nonimmortalized cell lines with the long-term cultivation. Our present and previous results made it possible to suppose that the formation of dicentrics (telomeric associations) in nonimmortalized "markerless" cell line, following the long-term mycoplasmal contamination, may prove additionally the role played by dicentrics in cell adaptation to in vitro conditions whatever the degree of transformation may be--nonimmortalized line or immortalized nontumorogenic or high tumorogenic lines.

Acholeplasma laidlawii↗
PubMed2000

[Hepatocyte proliferation and DNA content in chronic hepatitis C].

Apart from inflammatory reaction, the death of hepatocytes is also a characteristic of chronic hepatitis. Necroinflammation is followed by compensatory proliferation, which plays a rather important role in maintaining the liver function. Authors studied the DNA content of hepatocytes in patients with chronic hepatitis C, and determined the ratio of hepatocytes in phases G1, S and G2 to determine the hepatocyte proliferation and regeneration capacity of the liver. Liver biopsy samples were taken from 23 patients with chronic hepatitis C and from 16 with chronic hepatitis with non viral origin, from which nuclear suspension counts were done based on the histological slides. A total of 16 normal liver tissue samples served as control. The DNA index, G1, S, G2 and polyploid fraction were determined using the DNACE (Digital Image Analyzer for Nuclear Deoxyribonucleic Acid Content Estimation, KFKI/NIO, Hungary) digital imaging process. The DNA index was found to be significantly higher in the chronic hepatitis C than in the non-C group, with the verification of aneuploidy (DI > 1.10). The chronic non-C hepatitis cases showed lower G1 (88 +/- 6) and higher S (7.8 +/- 6.6) fractions. In comparison to the normal liver tissues, the chronic hepatitis C cases also revealed a significantly (p < 0.05) lower G1 (91 +/- 5) and a higher S (5.4 +/- 3.6) fraction, though staying behind the values found for the non-viral group. The deviation can be explained by the presentation of the HCV proliferation inhibitory effect. The polyploid cell fraction revealed a significantly higher value in the chronic non-viral cases as compared to the C virus group, reflecting on the decreased regeneration capacity of the liver. When comparing the HCV groups, significant differences were found between the mild and moderate cases in respect to the G1 and G2 fractions. At the same time, the moderate and severe cases showed statistical deviation regarding the DNA index. Chronic hepatitis C virus infection reduces the proliferation of hepatocytes and the regeneration capacity of the liver. The aneuploid DNA index reflects on genetic instability, which could be the basis of the malignant transformation of the cells.

Adult↗
PubMed2000

Amphidiploid Brassica juncea contains conserved progenitor genomes.

To perform a detailed study of genome evolution in the natural Brassica amphidiploid B. juncea, we have constructed two linkage maps based on RFLP (restriction fragment length polymorphism) markers; one generated from a cross between a resynthesized B. juncea (a chromosome doubled interspecific B. rapa x B. nigra hybrid) and a natural B. juncea cultivar, the other from a cross between two B. juncea cultivars. By using a common cultivar in both crosses, the two maps could be unambiguously integrated. All loci exhibited disomic inheritance of parental alleles in the natural x resynthesized cross, showing that B. rapa chromosomes paired exclusively with their A-genome homologues in B. juncea and that B. nigra chromosomes likewise paired with their B-genome homologues. The maps derived from the two crosses were also perfectly collinear. Furthermore, these maps were collinear with maps of the diploid progenitor species (B. nigra and B. rapa) produced using the same set of RFLP probes. These data indicate that the genome of B. juncea has remained essentially unchanged since polyploid formation. Our observations appear to refute the suggestion that the formation of polyploid genomes is accompanied by rapid change in genome structure.

Brassica↗
PubMed2000

Evidence of sexuality in European Rubus (Rosaceae) species based on AFLP and allozyme analysis.

Reproduction of polyploid Rubus species is described as facultatively apomictic. Pollination is needed for seed set, but most seedlings are produced asexually by pseudogamy. Although sexual processes may occur, clonal diversity can be extremely low. We performed a pollination experiment to investigate the breeding system and used allozyme and AFLP markers to analyze genetic variation among and within seed families in R. armeniacus and R. bifrons. Pollination either with self or outcross pollen was necessary to trigger seed set. Outbreeding marginally increased the number and quality of seeds compared with selfing. The enzyme PGI revealed some genetic variation within seed families. Seven other enzyme systems were monomorphic. The more detailed AFLP analyses with five primer pairs detected the same rate of genetic variation (14-17% of seedlings were genetically distinct) and confirmed the allozyme results for the same individuals. No genetic variation was found between the seed families from within a species collected in widely separated populations, but clear species-specific differences were observed. The results support the view that polyploid Rubus species are pseudogamous apomicts with low genetic diversity among and within seed families. However, sexual reproduction occasionally occurs and contributes to the maintenance of genetic variation within natural populations.

Journal Article↗
PubMed2001

Phylogenetic relationships and evolution of Crassulaceae inferred from matK sequence data.

Chloroplast gene matK sequence data were used to estimate the phylogeny of 112 species of Crassulaceae sampled from 33 genera and all six recognized subfamilies. Our analyses suggest that five of six subfamilies recognized in the most recent comprehensive classification of the family are not monophyletic. Instead, we recovered a basal split in Crassulaceae between the southern African CRASSULA: clade (Crassuloideae) and the rest of the family (Sedoideae). These results are compatible with recent studies of cpDNA restriction site analyses. Within Sedoideae, four subclades were also recovered: KALANCHOE:, Leucosedum, Acre, and AEONIUM:; evidence also exists for a TELEPHIUM: clade and SEMPERVIVUM: clade. The genus SEDUM: is highly polyphyletic with representatives spread throughout the large Sedoideae clade. Sympetaly and polymerous flowers have arisen multiple times in Crassulaceae and thus are not appropriate characters upon which to base subfamilial limits, as has been done in the past. One floral character, haplostemy, appears to be confined to the well-supported CRASSULA: clade. Our analyses suggest a southern African origin of the family, with subsequent dispersal northward into the Mediterranean region. From there, the family spread to Asia/eastern Europe and northern Europe; two separate lineages of European Crassulaceae subsequently dispersed to North America and underwent substantial diversification. Our analyses also suggest that the original base chromosome number in Crassulaceae is x = 8 and that polyploidy has played an important role in seven clades. Three of these clades are exclusively polyploid (SEMPERVIVUM: clade and two subclades within the KALANCHOE: and AEONIUM: clades), whereas four (Crassula, Telephium, Leucosedum, and ACRE: clades) comprise both diploid and polyploid taxa. Polyploidy is particularly rampant and cytological evolution especially complex in the ACRE: clade.

Journal Article↗
PubMed2000

Coevolution of A and B genomes in allotetraploid Triticum dicoccoides.

Data is presented on the coevolution of A and B genomes in allotetraploid wheat Triticum dicoccoides (2n = 4x = 28, genome AABB) obtained by genomic in situ hybridization (GISH). Probing chromosomes of T. dicoccoides with DNA from the proposed A/B diploid genome ancestors shows evidence of enriching A-genome with repetitive sequences of B-genome type. Thus, ancestral S-genome sequences have spread throughout the AB polyploid genome to a greater extent than have ancestral A-genome sequences. The substitution of part of the A-genome heterochromatin clusters by satellite DNA of the B genome is detected by using the molecular banding technique. The cause may be interlocus concerted evolution and (or) colonization. We propose that the detected high level of intergenomic invasion in old polyploids might reflect general tendencies in speciation and stabilization of the allopolyploid genome.

Chromosome Mapping↗
PubMed2000

[Effect of ectopic superexperssion of the anti-apoptotic gene bcl-2 on the level and character of karyotypic instability in the CHLL V-79 RJK Chinese hamster cell line].

Karyotypic destabilization in cells of Chinese hamster fibroblasts CHL V-79 RJK with ectopically overexpressed antiapoptotical human bcl-2 gene from pSFFV-bcl-2 vector has been analysed. Analysis of G-banded metaphase chromosomes from 4 clones with different levels of bcl-2 expression revealed an increased level of chromosomal instability in bcl-2-transfected cells. Besides, an increased percentage of aneu- and polyploid cells and high level of cells with different chromosomal aberrations was observed. The degree of karyotypic instability positively correlated with the level of bcl-2 expression in bcl-2-transfected cells. Cells of a clone with the highest bcl-2 expression at the 13th passage of cultivation displayed an almost 100% polyploidization and the presence of specific aberrations and a tricentric marker chromosome. Selection of cells with non-random specific chromosome changes was observed in pSFFV-bcl-2-transfected CHL V-79 RJK cells in the process of their long-term cultivation. By contrast, cells of the parental cell line, as well as the control pSFFV-neo transfectants, displayed a stable karyotype throughout the long period of cultivation. It is important that the presence of morphological markers of gene amplifications--DOO, DM, MH--was observed in bcl-2-transfected cells. These findings suggest that the overexpression of antiapoptotic human bcl-2 gene may result in destabilization of the karyotype structure in cells of Chinese hamster fibroblasts CHL V-79 RJK. The character and level of destabilization correlate with the level of ectopic overexpression of this gene.

Animals↗
PubMed2001

DNA cytometry confirms the utility of the Bethesda system for the classification of Papanicolaou smears.

BACKGROUND: Developed in 1989, the Bethesda System has largely replaced previous classifications of Papanicolaou (Pap) smears from the uterine cervix. The system is binary, dividing smears into two groups - low-grade, squamous, epithelial lesions (LSIL) or high-grade, squamous, epithelial lesions (HSIL). A third category, atypical squamous cells of undetermined significance (ASCUS), is used to classify minimal cellular changes that do not satisfy the criteria for the low- or high-grade categories. This study was designed to confirm the utility of this binary division and to compare the results with another classification system (the Munich II Nomenclature) that is not binary but contains three divisions or grades for dysplasia - low, intermediate, and high. METHODS: Pap smears were obtained from 593 women with a cytologic diagnosis of dysplasia based on the Munich System. Smears were then classified by the Bethesda System into LSIL or HSIL. Patients were followed for 2 years either with biopsy or repeat cytology. The initial smears were restained by the Feulgen method, and ploidy was evaluated by interactive DNA cytometry. RESULTS: Of 241 cases of LSIL, 39% were diploid, 57% polyploid, and 4% aneuploid. Of 352 cases classified HSIL, 4% were diploid, 17% polyploid, and 79% aneuploid. After 2 years of follow-up, 2 of 108 patients who were biopsied and who were originally classified as diploid progressed to cervical intraepithelial neoplasia/carcinoma in situ (CIN/CIS) whereas 109 of 217 patients who were aneuploid and biopsied were found to have CINIII/CIS. CONCLUSIONS: The two divisions of the Bethesda System, LSIL and HSIL, correlated with ploidy as evaluated by cytometry. Aneuploidy was found to be useful to separate cases of HSIL from those of LSIL as defined in the Bethesda System. Because of the binary division, use of a system with three divisions for dysplasia, such as the Munich II Nomenclature, creates a therapeutic dilemma because a single diagnostic category (usually the intermediate grade) may contain both self-limiting and progressive lesions. DNA cytometry of Pap smears was found to be useful as a routine procedure.

Carcinoma in Situ↗
PubMed2001

[Somatic polyploidy in neurons of the gastropod molluscs. II. Dynamics of DNA synthesis in the process of postnatal growth of CNS neurons in Succineid snail].

A study was made of the age dynamics of polyploidization and dynamics of DNA synthesis in neuron cell nuclei during the postnatal growth of the gastropod pulmonate snail Succinea lauta. According to cytophotometrical results, the degree of polyploidization in neuron nuclei increases from young to adult individuals, varying from 2c to 16,384c. In the visceral complex, the maximum and medium ploidy values of the neuron nuclei are higher by almost 4-8 times than those in cerebral and pedal ganglia. The medium level of ploidy in adult snails increases by 5.7 times in the visceral complex of ganglia and by 4.1-4.2 times in the pedal and cerebral ganglia. According to 3H-thymidine autoradiography, DNA synthesis in neuron nuclei occurs during the whole life of the snail. In young individuals the neurons have the highest activity of DNA synthesis--the index of labeled nuclei of neurons making in total 50.2%. In older age, a steady decrease in the index of labeled nuclei is observed--in total to 35.8% and 7.0% in small and large adult snails, respectively. The state of summer hibernation completely stops DNA syntheses in neurons, but emergency from hibernation is accompanied by restoration of DNA syntheses.

Animals↗
PubMed2001

Genomic in situ hybridization (GISH) discriminates between the A and the B genomes in diploid and tetraploid Setaria species.

Genomic in situ hybridization (GISH) was used to investigate genomic relationships between different Setaria species of the foxtail millet gene pool (S. italica) and one interspecific F1 hybrid. The GISH patterns obtained on the two diploid species S. viridis (genome A) and S. adhaerans (genome B), and on their F1 hybrid showed clear differentiation between these two genomes except at the nucleolar organizing regions. Similar GISH patterns allowed differentiation of S. italica from S. adhaerans. However, GISH patterns did not distinguish between the genomes of S. italica and its putative wild ancestor S. viridis. GISH was also applied to polyploid Setaria species and enabled confirmation of the assumed allotetraploid nature of S. faberii and demonstration that both S. verticillata and S. verticillata var. ambigua were also allotetraploids. All these tetraploid species contained two sets of 18 chromosomes each, one from genome A and the other from genome B. Only one polyploid species, S. pumila, was shown to bear an unknown genomic composition that is not closely related either to genome A or to genome B.

Animals↗
PubMed2000

Trophoblast cell invasiveness and capability for the cell and genome reproduction in rat placenta.

Using 3H-thymidine labeling and cytophotometric DNA content measurement in nuclei and mitotic figures, proliferative activity and genome reproduction peculiarities have been studied in highly invasive, primary and secondary giant trophoblast cells (pGTCs and sGTCs, respectively) as well as in the low invasive junctional zone and labyrinth trophoblast cells (JTCs and LTCs) of rat placenta. It has been shown that different extent and patterns of phagocytic activity of pGTCs and sGTCs correspond to different developmental stages. An inverse relationship has been observed between capability for mitoses and invasive and phagocytic activities. The pGTCs and sGTCs lose their mitotic activity from the start of their differentiation. Nevertheless, they continue reproduction of their genome and undergo a series of endoreduplication cycles to reach the ploidy degree of 256-1024c. In contrast, the JTCs and LTCs have, as a rule, no invasive and phagocytic activities, while preserving proliferative properties up to 15 day of gestation. They undergo initial polyploidization via uncompleted polyploidizing mitoses up to octaploid level and then pass to the endoreduplication cycle that excludes mitoses. Such a way of cell reproduction has been suggested to play a protective role, as it rules out contacts of the trophoblast cell genome with chromosomes of the phagocyted allogenic maternal tissue.

Animals↗
PubMed2000

Genome multiplication in the tertiary giant trophoblast cells in the course of their endovascular and interstitial invasion into the rat placenta decidua basalis.

Processes of invasion of the tertiary giant trophoblast cells (tGTCs) into the uterine wall in the course of implantation of the rat embryo at 10-15 days post coitum (dpc) were studied. Reproduction of tGTCs was evaluated using 3H-thymidine incorporation and cytophotometric measurement of the nuclear DNA content. 1. Patterns of trophoblast invasion. Two patterns of invasion were observed: endovascular (from 10 to 15 dpc) and interstitial (from 12 to 15 dpc), via extracellular matrix of endometrial stroma towards the central arterial channel. The both types of the tGTC invasion seem to take part in modification of the arterial wall. The tGTCs were shown to differentiate from cambial trophoblast cells of ectoplacental cone (EC) or junctional zone of placenta. 2. Peculiarities of reproduction of tGTCs. By the start of the endovascular and interstitial migration, tGTCs lose completely their capability for mitotic divisions and are found autoradiographically to stop incorporation of 3H-thymidine soon after beginning of their migration. Cytophotometric measurements of the nuclear DNA content have shown tGTCs to be polyploid. Their degree of ploidy is mainly 8-32c, which is by 1-2 classes of ploidy higher than that of the initial cambial cell populations of ectoplacental cone (EC) and junctional zone trophoblast cells (JTCs). Since the replication processes in tGTCs are limited, their polyploidization seems to occur within cambial populations of the trophoblast cells. The final genome multiplication cycles in the beginning of the tGTC invasion can be accomplished only via endoreduplication, i.e., with the complete elimination of the mitotic mechanism. The not too high level of tGTC ploidy, 8-32 c, probably does not prevent the tGTC deep invasion against the blood flow and through the extracellular matrix and may be of a protective significance in their interrelations with allogenic maternal tissues.

Animals↗
PubMed2001

Genotypic variation in tetraploid wheat affecting homoeologous pairing in hybrids with Aegilops peregrina.

The Ph1 gene has long been considered the main factor responsible for the diploid-like meiotic behavior of polyploid wheat. This dominant gene, located on the long arm of chromosome 5B (5BL), suppresses pairing of homoeologous chromosomes in polyploid wheat and in their hybrids with related species. Here we report on the discovery of genotypic variation among tetraploid wheats in the control of homoeologous pairing. Compared with the level of homoeologous pairing in hybrids between Aegilops peregrina and the bread wheat cultivar Chinese Spring (CS), significantly higher levels of homoeologous pairing were obtained in hybrids between Ae. peregrina and CS substitution lines in which chromosome 5B of CS was replaced by either 5B of Triticum turgidum ssp. dicoccoides line 09 (TTD09) or 5G of Triticum timopheevii ssp. timopheevii line 01 (TIMO1). Similarly, a higher level of homoeologous pairing was found in the hybrid between Ae. peregrina and a substitution line of CS in which chromosome arm 5BL of line TTD140 substituted for 5BL of CS. It appears that the observed effect on the level of pairing is exerted by chromosome arm 5BL of T turgidum ssp. dicoccoides, most probably by an allele of Ph1. Searching for variation in the control of homoeologous pairing among lines of wild tetraploid wheat, either T turgidum ssp. dicoccoides or T timopheevii ssp. armeniacum, showed that hybrids between Ae. peregrina and lines of these two wild wheats exhibited three different levels of homoeologous pairing: low, low intermediate, and high intermediate. The low-intermediate and high-intermediate genotypes may possess weak alleles of Ph1. The three different T turgidum ssp. dicoccoides pairing genotypes were collected from different geographical regions in Israel, indicating that this trait may have an adaptive value. The availability of allelic variation at the Ph1 locus may facilitate the mapping, tagging, and eventually the isolation of this important gene.

Crosses, Genetic↗
PubMed1975

[Giant cells in the placenta of the bactrian camel in the fetal period of development].

Polyploid giant cells resulting from differentiation of normal cytotrophoblast cells were found in the composition of the placenta cytotrophoblast of the Bactrian camel. In the placenta of the Bactrian camel the transformation of cytotrophoblast cells into multinuclear giant cells is realized via endomitotic polyploidization and distinctly reflects active synthetic processes occurring in these cells related with the trophic function of the placenta. It may be supposed that giant cells of the placenta of female Bactrian camels also participate in the endocrinous function of the placenta. Their histolitical function is completely excluded.

Animals↗
PubMed2002

[The detection of living triploid of Haliotis discus hannai--directly making chromosome sample of mantle and epipedium tentacle].

Ploidy detection method of living body is a very important component part in polyploid breeding. There were few reports about chromosome ploidy detection of adult abalone (Haliotis discus hannai), except preparing adult abalone chromosome by means of chopping method using gill tissues and squashing method using gonad, also with these methods the abalone should be killed for getting these tissues. In polyploid breeding living triploid abalones are needed, so ploidy detection technique of living abalone is especially important. In this paper the orthogonal experiment of three factors and three levels L9(3(4)) using mantle and epipodium tentacle as material of living tissues which were vido immersing in PHA solution for preparing chromosome and count the frequence of cell division was first reported. Three factors and three levels were raising temperature: 16 degrees C, 18 degrees C, 20 degrees C; PHA concentration: 0.5%, 1.0%, 1.5%; sampling time: 5:00-6:00, 17:00-18:00, 23:00-24:00, respectively. The tests were repeated two times. The test results showed that the optimal patterns effecting the mitotic frequency of three factors and three levels in triploid abalone detection of chromosome from mantles and epipodium of living bodies were: raising temperature 20 degrees C, PHA concentration 1.0%, and sampling time 17:00-18:00. The order of three factors was: raising temperature-->PHA concentration-->sampling time. Under optimal pattern of three factors and three levels many clear, proper in length and well-scattered metaphase chromosomes could be obtained. The advantages of preparing chromosome using mantles and epipodium tentacle were sampling convenient, no body size restriction and no influence of survival of abalone. After using PHA treated tissues, mitotic frequency could be improved and 1.00% PHA concentration was the best. The key of chromosome preparation was the cells in mitotic metaphase, so the time of sampling was important. During 17:00-18:00, sampling of abalone many mitotic cells could be obtained because abalones were vigorously active at night. Biological zero degree of abalone was 7.6 degrees C. Under 7.6 degrees C abalone could not grow. At 20 degrees C abalones move and prey the most vigorously and grow fastest. Therefore a lot of cells are in mitotic metaphase.

Animals↗
PubMed2002

[Effects of Helicobacter pylori infection on porcine gastric epithelial cell proliferation].

OBJECTIVE: To investigate the association between porcine gastric epithelial cell proliferation and Helicobacter pylori (Hp) infection. METHOD: Animal models of gastritis associated with Hp infection were established using "Chinese No.1 pigs". The expressions of proliferating cell nuclear antigen (PCNA) and DNA polyploid content in porcine gastric epithelial cells were quantitatively assayed by means of immunohistochemistry and Feulgen stain respectively. RESULTS: The values of PCNA labeling index (LI) in the porcine gastric epithelial cells of the experimental group were significantly higher than those of the control group (40.95+/-3.60 vs 29.4+/-12.82, P<0.01). The DNA diploid or approximate diploid content in the gastric mucosa of the pigs was significantly lower (70.78% vs 90.65%, P<0.01), but the proliferation polyploid and non-doubleploid of DNA significantly higher in the experimental group than in the control group (P<0.01). CONCLUSION: Hp infection may play a role to enhance the proliferation of gastric epithelial cells in pigs.

Animals↗
PubMed2002

[Morphofunctional changes in hepatocytes during the early postnatal development of rats experimentally infected with the intestinal protozoan pathogen, Cryptosporidium parvum (Coccidia, Sporozoa)].

Morphofunctional changes in hepatocytes of 10-14-day old rats were followed in norm and after experimental infection with different doses of oocysts of Cryptosporidium parvum. The liver index (ratio between the liver and body masses) varied with the intensity of invasion on the background of slowing down up to the total cessation of animal growth rates, and all this obviously pointed to severe pathology. In the infected rats, some cytological indices were shifted compared to the norm: protein amount and the average number of genomes per hepatocyte were seen to increase, the normal ratio between cells with different ploidy levels being violated. The particular correlation analysis was employed to distinguish between the ontogenetic (animal growth related) and pathologic (related to the infection intensity) polyploidization and hypertrophy in hepatocytes. In 10-14-day old rats, the former is affected primarily by the increase in the share of multinuclear hepatocytes, whereas the latter is accomplished by the increase in the number of cells with polyploid nuclei (4c and 4c x 2 cells). In the heavily infected rats, the ontogenetic polyploidy was almost totally suppressed due, presumably, to their growth rate inhibition, the rise in hepatocyte ploidy resulting form the obvious pathological changes in the liver. In the infected rats, the ontogenetic hypertrophy of hepatic parenchymatous cells was not manifested, and the observed protein accumulation in hepatocytes also resulted from the pathological changes in the liver. It is obvious that changes in cell hypertrophy (protein content) may serve as a more susceptible tool that readily perceives the host's stress experienced due to the parasitic infection (cryptosporidiosis), than cell ploidy: the levels of the respective responses of these two parameters differing by 4 times. However, due to the known reversible nature of hypertrophy, it cannot be used for the aims of a long-term prediction about the future mode of liver functioning in the animal that survived cryptosporidiosis. Unlike, such a parameter as frequencies of hepatocytes with different ploidy levels is much more useful in this respect.

Animals↗