Liver sinusoidal cell ultrastructure in partially hepatectomized rats

Two-thirds of the liver was removed from male Wistar rats weighing 160–200 g. In response to the operation phasic changes occurred in the structure of the lysosomal apparatus in the Kupffer cells. The number of primary lysosomes in the Kupffer cells was increased 2.5 h after partial hepatectomy, and the size and polymorphism of the lysosomes were increased after 9 h. At the peak of mitotic activity of the hepatocytes (30 h after partial hepatectomy) mainly secondary lysosomes were identified in the Kupffer cells, but 48 h after the operation, on the other hand, their number was reduced, although young forms of primary lysosomes appeared. Manifestations of fatty infiltration predominated in the endothelial cells and reached a maximum at the peak of mitosis of the hepatocytes. The results are evidence that ultrastructural changes in the sinusoidal cells depend on the phases of reparative regeneration of the liver.Laboratory of Pathophysiology, Department of General Pathology, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 12, pp. 729–733, December, 1979.     

Regeneration and growth of the liver in 3-week-old mice of different strains

At the age of 3 weeks, C57BL mice have comparatively low proliferative activity of their hepatocytes when the liver grows normally, but also during regeneration of the liver 44 h after its extensive resection (mitotic index 16%). Animals of the same age but of other strains (noninbred, CBA, and CC57BR), however, in most cases have a higher mitotic index of their hepatocytes both under normal conditions and during regeneration of the liver (42, 70, and 60%). This pattern of interlinear differences in mitotic activity of the hepatocytes during growth and regeneration of the liver was still found 7 days after the beginning of the experiment. The results indicate genetic determination of the level of proliferative activity of cells.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR, A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 475–477, April, 1976.     

Effect of absence of polyploid hepatocytes on regeneration in the liver

An autoradiographic study with [³H]thymidine showed that the hepatocytes of young sexually mature guinea pigs commence the phase of DNA synthesis 25 h after partial hepatectomy. Peaks of the number of labeled nuclei were found 30, 45, and 60 h after the operation. Two waves of mitoses were found by counting mitotic figures in squash preparations: 40 and 55 h after hepatectomy. A cytophotometric study of the DNA content showed that practically all the mononuclear and binuclear hepatocytes contained diploid nuclei 3 and 5 days after the operation. By the end of the 7th day of regeneration there were 6% of mononuclear tetraploid cells. The number of binuclear cells fell during the period of regeneration studied from 16 to 8%. It is concluded that the principal cytological mechanism of liver regeneration in guinea pigs is normal mitosis terminating in separation of the cells.Department of Histology and Embryology, Second Moscow Medical Institute. Laboratory of Functional Morphology of the Chromosomes, Institute of Molecular Biology, Academy of Sciences of the USSR. Laboratory of Cytology, Institute of Developmental Biology, Academy of Sciences of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. M. Lopukhin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 221–224, August, 1977.     

Synthesis and localization of α-fetoprotein during regeneration of the liver in mice

The main site of localization of -fetoprotein (FP) in mouse liver regenerating after CCl₄ poisoning or partial hepatectomy was in the typical mature hepatocytes that account for not more than a few per cent of the total number of residual hepatocytes. Morphologically they were indistinguishable from the main mass of hepatocytes and they retained on their surface bile capillary antigen. The change in their number and in the brightness of their fluorescence in liver sections corresponded to the dynamics of the FP level in the animals' serum. During regeneration of the liver in mice FP is evidently produced mainly by mature hepatocytes.Laboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR. Laboratory of Clinical Immunology, Institute of Experimental and Clinical Oncology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR O. V. Baroyan.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1251–1254, October, 1976.     

Synthesis of α-fetoprotein and albumin by human embryonic hepatocytes

Population aspects of the production of specific secreted proteins (serum albumin and -fetoprotein) were studied in cultures of hepatocytes from human embryos at 6–12 weeks of development. A method based on local hemolysis in gel using sheep's erythrocytes conjugated with antibodies against the proteins for testing, was used. The overwhelming majority of hepatocytes were shownto synthesize both proteins.Laboratory of Human Cytogenetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR. Laboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of, Medical Sciences of the USSR, Moscow. (Presented, by Academician of the Academy of Medical Sciences of the USSR L.M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 711–713, June, 1977.     

Synthesis of α-fetoproteinin vitro by human hepatocytes,singly and in microcolonies

By a combination of microelectrophoresis and precipitation in polyacrylamide gel, -fetoprotein (-FP) produced by single hepatocytes and by microcolonies of hepatocytes was determined. Liver cells from 6–13-week-old human fetuses were cultivatedin vitro for 2–5 days. -FP was found to be produced in amounts of between 70 and 800 pg per cell by 23 of 28 single hepatocytes and by 89 of 91 microcolonies consisting of 2 to 35 cellsLaboratory of Immunochemistry and Diagnosis of Tumors, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR. Laboratory of Human Cytogenetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 481–484, April, 1977.     

Esterase spectrum in hepatocytes and Kupffer cells of the regenerating liver

The esterase spectrum in hepatocytes and Kuppfer cells of the regenerating rat liver was determined by electrophoresis in starch gel. The relative number of Kupffer cells, the percentage of phagocytic Kupffer cells, and the frequency of mitosis in the hepatocytes were determined. The esterase spectrum of hepatocytes isolated from the intact liver consisted of six zones, and that of the Kupffer cells of five zones of enzyme activity. The spectrum of the hepatocytes was simplified 2.5 h after partial hepatectomy, additional bands of activity appeared toward 9 h, and these persisted until 24 h after the operation. The original esterase spectrum was restored 48 h after the operation. A similar reorganization of the esterase spectrum was observed in the Kupffer cells but this was not fully restored 72 h after partial hepatectomy.Laboratory of Pathophysiology, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 44–46, July, 1977.     

Kinetics of cell proliferation in the regenerating rat liver after subtotal resection

Between 78 and 82% of the weight of the liver was resected in noninbred male rats. Maximal mitotic activity of the hepatocytes was observed 38–48 h after the operation. Pulse labeling with [³H]-thymidine showed that the G₂ period is 6 h and the minimal duration of the S period is also 6 h. During regeneration of the liver after subtotal resection asynchronization of the entry of the hepatocytes into the S period and mitosis and delay of the cells in the G₁ and G₂ periods were observed. The above-mentioned changes in proliferation of the hepatocytes are the result of a disturbance of intracellular metabolism in response to an extremal functional demand.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 12, pp. 723–726, December, 1978.     

Structure of the liver as a possible factor in the regulation of α-fetoprotein synthesis

During regeneration of the mouse liver after poisoning with CCl₄ and paracetamol, hepatocytes containing -fetoprotein (FP) lose their membrane antigen that served as marker for biliary capilaries. Both during regeneration and in early postnatal development, cessation of FP synthesis by the cells coincides with the appearance of an antigen marking the biliary capillaries on their surface. It is suggested that cessation of FP synthesis is the result of establishment of a system of contacts characteristic of the definitive hepatic column.Laboratory of Immunochemistry and Diagnosis of Tumors, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 6, pp. 576–579, June, 1979.     

Origin of the Kupffer macrophages in the regenerating liver

[³H]Thymidine was injected intraperitoneally into male Wistar rats in a dose of 5 Ci/g, and two thirds of the liver was resected 1 h later. Control animals underwent a mock operation. Indices of labeled nuclei (ILN) of the hepatocytes were moderately increased 3 h after partial hepatectomy, the increase still continued for 48 h, but was replaced by a decrease 48 h after the operation. ILN of the Kupffer cells was 10 times higher 3 h after the operation than in the control, it reached a maximum 9 h after the operation, and then fell, although still remaining higher than in the control. It is concluded that Kupffer cells enter the liver from the bone marrow.Laboratory of Pathophysiology, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 5, pp. 598–600, May, 1978.     

Effect of physical training on regeneration of the rat liver after partial hepatectomy

Training rats by swimming was shown to cause changes in the functional state of the hepatocytes, accompanied by changes in the distribution of nuclei relative to their DNA ploidy classes. The blood sugar and liver glycogen concentrations of the trained animals 20 and 48 h after partial hepatectomy were significantly higher than in untrained rats. Reparative regeneration after partial hepatectomy in trained rats is characterized by a unique distribution of nuclei among DNA ploidy classes and by the entry of only diploid nuclei into the phase of synthesis 20 h after the operation.Central Research Laboratory, Novosibirsk Medical Institute. Laboratory of Endocrinology and Laboratory of Biophysics, Institute of Clinical and Experimental Medicine, Siberian Division, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 10, pp. 483–486, October, 1978.     

Effect of stimulation of Kupffer cells by prodigiosan on regeneration of hepatocytes

The effect of the polysaccharide ofBacillus prodigiosus (prodigiosan) on DNA synthesis and mitotic activity of the hepatocytes was studied in the regenerating liver of male Wistar rats. After administration of the stimulator in a dose of 50 g per rat 24 h before partial hepatectomy the indices of labeled nuclei and mitotic indices were higher and reached their maximum sooner in the hepatocytes in the experimental animals than in the controls. It is suggested that the stimulating effect of prodigiosan is connected with activation of the Kupffer cells of the liver.Laboratory of Pathophysiology, Institute of Clinical and Experimental Medicine, Siberian Branch, Academy of Medical Sciences of the USSR, Novosibirsk. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 7, pp. 69–71, July, 1978.     

Characteristics of human embryonic hepatocytes cultivated in vitro

A simple and reproducible method of monolayer cultivation of hepatocytes from 7–12-week human fetuses is suggested. Such cultures are capable of limited growth, they can be maintained without subculaute for 4–6 weeks, and they preserve certain specific characteristics: synthesis of such characteristic serum proteins as albumin and -fetoprotein, the presence of a high glycogen content and high monoamine oxidase activity, and the characteristic reaction to high concentrations of glucocorticoid. These properties can be used in experimental genetics as markers or for selection purposes.Laboratory of Human Cytogenetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 79, No. 5, pp. 123–125, May, 1975.     

Effect of gnotobiotic conditions on the histophysiology of liver and spleen tissues

The liver and spleen of gnotobiotic Wistar rats were studied by histochemical methods and the liver electron-microscopically. Under germfree conditions of existence of the animal the succinate dehydrogenase and nonspecific esterase activity in the liver decreased, fatty infiltration of the cytoplasm of the hepatocytes and Kupffer cells increased, and some of the cells developed fatty degeneration. Meanwhile acid phosphatase activity and the number of lysosomes increased in the biliary poles of the hepatocytes, whereas in the spleen destruction of erythrocytes and the liberation of free iron and pigments, which stimulate the excretion of bile in germfree animals, were increased.Laboratory of Embryonic Histogenesis, Research Institute of Human Morphology, Academy of Medical Sciences of the USSR. Research Laboratory of Experimental Biological Models, Academy of Medical Science of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 1, pp. 81–84, January, 1978.     

Role of growth hormone in regulation of polynucleotide-phosphorylase activity in rat liver

Hypophysectomy in rats is followed by a significant increase in polynucleotide-phosphorylase (PNPase) activity in ribosomal fractions of the liver. Injection of growth hormone into hypophysectomized animals leads to inhibition of PNPase activity. Within the dose range from 5 to 100 g the dose—effect curve is linear. The action of growth hormone is most marked 18h after a single injection.Laboratory of Enzymology, Academy of Medical Sciences of the USSR, and Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 2, pp. 162–163, February, 1980.     

Localization of albumin,transferrin, andα-fetoprotein in normal and regenerating mouse liver

A technique of tissue fixation with a mixture of acetone and formalin followed by embedding in paraffin wax, enabling good detection of antigens, including serum proteins, is described. By means of this method the distribution of albumin, transferrin, and-fetoprotein was described in normal and regenerating mouse liver. Both under normal conditions and during regeneration albumin and transferrin are contained by strictly the same hepatocytes.-Fetoprotein is found in the regenerating liver independently of the other two proteins, although it is found in the same zones. Albumin and transferrin are found only in the perinecrotic zone in each cell containing-fetoprotein.Laboratory of Immunochemistry and Diagnosis of Tumors, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 5, pp. 626–630, May, 1978.     

Activity of nonspecific esterases and α-glycerophosphate dehydrogenase and fat content in the regenerating chicken liver

The results of a histochemical study of changes in the activity of nonspecific esterases and -glycerophosphate dehydrogenase (-GPD) and the fat content in the regenerating liver of domestic chickens are given. Accumulation of fat in the hepatocytes in the early states of regeneration (1st–5th days of the experiment) is due partly to a decrease in nonspecific esterase activity. Maximal steatosis in the liver is also accompanied by an increase in -GPD activity, evidence of intensification of glycolysis and of primary synthesis of triacylglycerides — the reserve lipids of the liver — in the period of regeneration.Department of Zoology, Erevan University. (Presented by Academician of the Academy of Medical Sciences of the USSR, A. P. Avtsyn). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 6, pp. 547–550, June, 1979.     

Growth-stimulating action of some nitroso compounds on organ cultures of mouse and rat embryonic liver

The transplacental and direct action of nitrosomethylurea on organ cultures of the liver from 18–20-day CBA and C57BL mouse embryos and of diethylnitrosamine on liver cultures from noninbred rat embryos was studied. The nitroso compounds accelerated adaptation of the explants, increased the viability of the cultures compared with normal, and led to hyperplastic proliferation of the small basophilic cells whose survival rate under both normal and experimental conditions was higher than that of ordinary embryonic hepatocytes. The growth-stimulating effect depended on the object (species, line of animals) and the factor to which it was exposed (carcinogen, mode of administration).Department of Carcinogenic Agents, Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR L. M. Shabad.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 12, pp. 716–719, December, 1979.     

A micromethod of immunodiffusion

A method of counterimmunodiffusion using a technique of horizontal micromanipulation is described by which it is possible to detect 1–10 ng protein in 0.3–1.2 l of test fluid.Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. I. Ioffe.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 630–631, May, 1977.     

Response of cardiomyocytes of the right heart to trauma of the left

A myocardial infarct in the left ventricle was produced in adult rats weighing 120–160 g by ligation of the left coronary artery; the left atrium was injured; or a mock operation was performed and the pericardium was removed. On the fifth day after the operation dividing myocytes were found in the right atrium (mitotic index 0.7–8.8) and in the subepicardial zone of the right ventricle (mitotic index 0.8–2.9). In old rats weighing 300–430 g, on the third day after the various types of injury to the myocardium, mitotic activity was found in the myocytes of the left auricle (1–5.1), and in one of eight cases in the right auricle (4.2); single mitoses also were found in the subepicardial zone of the left ventricle.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 5, pp. 610–612, May, 1977.