ABSTRACT
The present study was designed to investigate the effect of gossypol on the reabsorption and excretion of ~(42)K in rats and guinea pigs by using autoradiographic technique, and selected the well known tubulo-toxic agent, gentamicin as a positive control for a comparative study to evaluate whether gossypol exerts nephrotoxic effect. Our results confirmed that gentamicin could induce significant decrease or inhibit ~(42)K reabsorption and cause structural damage of renal tubules. Gossypol could also affect the reabsorption function of proximal tubule, but did not appear to act as a tubulotoxic agent comparable with gentamicin to cause injury of the renal tubules.
ABSTRACT
Gossypol has been shown to cause a side effect hypokalemia. This study was designed to evalulated the possible role of gossypol in relation to renal potassium loss by using histochemical method for comparative analysis of gossypol and gentamicin, a well known tubulo-toxic agent, as positive control with respect to nephrotoxic demage in rats and guinea pigs. The results indicated that gossypol had obvious effect on reabsorption function by inducing transitional decrease of membrane enzymes activities of renal tubular cells but had no effect as comparable with gentamicin to cause structureal damage of tubular cells.
ABSTRACT
The present study reported the effect of two male antifertility agents gossypol acetic acid and GTW on DNA of C3H10T1/2 mouse fibroblasts. Our results showed that the cells treated with gossypol or GTW at high concentration (2-3 ?g/ml) for 4 hours, show silver grains in their nuclei as much as the positive control group, N-methyl N′-nitro-N-nitrosoguanidine (MNNG) a known carcinogen. However, if the agents were used at moderate concentrations (0.5-1?g/ml), the silver grains were much less, if the concentrations of gossypol or GTW were of 0.1-0.3 ?g/ml, the silver grains were as less as the control group. In a colony-forming test, we found that the cells lost their proliferate ability, since no colonies could be formed, if gossypol or GTW were of high concentration; while at moderate or low concentrations, the colony-forming rate was as high as 8.1-10.5％. Taking all of these results into consideration, we suggest that high concentrations of gossypol or GTW can damage cell DNA severely, moderate concentration of the agents break cell DNA to a certain extent, but the cells can repair, while low concentration of gossypol or GTW exert no obvious effect on cells. The significance of these observations was briefly discussed.
ABSTRACT
Our previous study showed that malignant phenotype of human promyelocytic leukemia cells could he suppressed by fusion of them with mouse reticulocytes. In order to investigate the morphological changes for malignancy reversion, the present experiment was designed to study the microscepic and submicroscopic structure of cybrid cells and compared with their parental tumor cells. The results indicated that during the short period of cybrid cell cultivation, nuclei of numerous cybrid cells became pyknotic and eccentric, and some cells showed the process of nuclear expulsion (denucleation). The cybrids which cultivated for long period in vitro developed into more mature cells along both myeloid and erythroid differentiation pathway. The effects of mouse reticulocyte cytoplasmic factor on differentiation pathway of human promyelocytic leukemia cells were discussed.
ABSTRACT
A method described by Harrison has been adopted and modified by us for the separation of intermediate and late erythroblast cells from 15 day embryonic liver of pregnant Wistar rat. The method consisted briefly of preparation of fetal liver cell suspension and the separation of cell types in a 40% and 70% nonlinear Percoll gradient system. Using this method, we can obtain about 96% of hemogenous population of intact and viable intermediate and late erythroblasts. Examination of tho separated cells by Giemsa and benzidine staining and by electron microscopic observation indicated that no granulocytes or other white blood cells could be detected, except for some contamination of about 1% of proerythroblasts and 3% of reticulocytes in the fraction. Trypan blue vital staining demonstrated that there were over 95％ of the cells maintained viable after separation, they could be used directly for the study of cell differentiation as well as biochemical analysis. SO, this is an economical, simple and easy technique to operate which proved to be a useful mean for obtaining enrich population of intermediate and late erythroblasts in research in the field of cell biology.
ABSTRACT
Junctions of myocardial cell, specially the intraeellular junctions of transverse tubule system with sarcoplasmie reticulum membranes were observed and described in the present paper. The tubular invaginations of the sarcolemma constitutes the transverse tubule (T tubule) which surround the myofibril in rabbit. The transverse tubular system of cardiac muscle are well developed. The tubule has an elliptical shape in cross section and 15 nm in diameter and is constantly located at the level of Z line. The sarcoplasmic retieulum consists of a simple plexiform arrangement of tubular elements forming a loose network around the myofibrillae. Small terminal expansions of the reticulum are closely applied to the membrane of the T tubules to form Diad. The membranes of the small flattened expansions of the reticulum and T tubules are in contact with each other, but the lumina of the two elements do not communicate. There is a gap of about I0 nm between them and foot processes from the membrane of sarcoplasmic reticulum are regularly extended toward the Ttubules. In addition, intracellular membranous junctions are observed between T tubules and sarcoplasmic reticulum of Diad. Each junction with membrane area of about 375 nm long becomes thicker and divides into two layers. Between them there is a gap of 31 nm wide, in which it is filled up with electron, dense material, forming some discontinuous spots which consisted of dense and light areas arranged at regular intervals.
ABSTRACT
Mutagenesis of several male contraceptives in sperm bead anomalies was investigated. Results show that glycosides of tripterygium wilfordii hook (GTW) and its monomer T13, microwave induce sperm head anomalies. However, gossypol and monomer T4 and GTW do not induce sperm head anomalies. Adult male mice and rats were given orally GTW, monomer T4, T13 and gossypol. These chemical agents were delivered in 1% methylcellulose. Result indicated that frequency of abnormal sperm heads in GTW, T13 groups were significantly increased, while frequency of abnormal sperm heads in T4 and gossypol-treated animals were similar to that of normal controls. When male mice were exposed to microwaves of 0.5 kW for 1-2 min, for five weeks abnormal shape of spermatozoa could be found.
ABSTRACT
The experiment was designed to compare the changes of cytoskeleton (including tubulin and actin) and cell surface fibronectin (FN) between NIH 3T3 cell line and transformed NIH 3T3 cell line by genome DNA of human lung adenocarcinoma cell line AGZY. We stained and observed these cells using immunohistochemical methods with antibody against bovine brain tubulin, phalloidin and self-made affinity column purified antibody against porcine plasma FN.Our results showed that the bundles of actin and tubulin are damaged seriously, demonofrating an unclear cytoskeleton structure and diffused fluorescence over the cells when they were transformed. The amount of membrane FN on transformed cell surface decreases significantly which is only 1/9 of NIH 3T3. The FN distribution altered markedly from thin threadlike network to spots and speckles.These results suggested that cell transformation was a complex event including the changes of cytoskeleton system and cell surface glycoproteins. In addition, it might also indicate that cause and effect relationship existed between these changes and the alteration of cell phenotype and loss of growth control.
ABSTRACT
The present study is designed to establish a xenograft model of human promyelocytic leukemia cell mutant (HL-60-AR) deficient in hypoxanthine guanine phosphoribosyltransferase (HGPRT) in nude mice. A solid leukemia sarcoma developed after subcutaneous inoculation with HL-60-AR cells. Comparative studies of HL-60-AR/Nu tumor cells in nude mice and cultured HL-60-AR cells in vitro revealed virtual identity as shown by light microscopic morphology, ultrastructure of cell, cytochemistry, chromosome analysis, LDH isoenzyme pattern, genetic markers and differentiated characters assay. Up to now, twelve generations haw been transmitted in rive by inoculating with the solid tumor Cells developed in nude mice. This nude mice model in which human leukemia cells grew could be considered as a useful model for in rive studies of human leukemic cells proliferation, differentiation and the screening for anti-leukemia drugs.
ABSTRACT
The heterospecies hybrid cells(HL-N)from the fusion of human promyelocy-tic leukemia mutant cells(HL-60-AR)and mouse bone marrow nucleated red cellswere established in HAT selective medium.Malignant phenotype comparative analy-sis between parental tumor cells and hybrid cells showed that growth ability ofhybrid cells was decreased.The hybrid cells reduced their DNA synthesis rate andlost the ability of colony-forming in 0.3% soft agar medium.The cells lost tumor-producing ability when they were transplanted into nude mice also.Inhibition orreduction of c-myc oncogene expression was demonstrated by Northern molecularhybridization techniques.The ultrastructure of hybrid cells were also different fromtheir parental cells.These results mentioned above showed that the mouse bone mar-row nucleated red cells might provide some peculiar factors(both nuclear factorsand cytoplasmic factors)to inhibit the expression of HL-60-AR cell malignant phe-notypes.
ABSTRACT
The present study reported that 5srRNA from reticulocytes of rabbit could pass into the nucleus of mouse myeloma cells SP2/0,and in the mean time DNA synthesis and cells division were markedly suppressed. In a separate experiment, the rRNA was extracted from embryonic liver and erythrocytes of rabbit or rat and analysed by agarose electrophoresis method. The result indicated that the amount of 5srRNA in various period of the development of erythrocyte is changed along with denucleation process. Thus it is likely that 5srRNA of mammalian erythrocyte plays a role in reversing malignant phenotype of tumor cells and promoting denucleation of mammalian erythrocyte through inhibiting DNA synthesis.
ABSTRACT
5srRNA was isolated and purified from the reticulocytes of rabbit. It labeled with ~(125)I, then incubated with mouse myeloma cells (SP2/0). By autoradiography it was observed that ~(125)I-SsrRNA could pass into the nuclei of the cells. In a separate experiment, it showed that the incorporation rate of ~3H-TdR into nuclei of SP2/0 after incubation with 5srRNA was decreased as compared with that f control group, hence the result indicates that 5srRNA inhibits DNA synthesis of the SP2/0 cells and it seems to play a role in the regulation of gene expression through its hybridization with DNA sequences of the SP2/0 cells. Thus it is likely that 5srRNA might act as "erythroid denucleation factor".
ABSTRACT
The present study was designed to investigate the effects of cytochalasin E(CE) on the integrity of Sertoli cell barrier. The results indicate that: (1) In the CE-treated testis(1000-2000 ?mol/L CE/testis, 6-14 hr), actin filaments of the ectoplasmic specialization (ES) in area of Sertoli cell barrier were disrupted, the accumulation of amorphous material and fragmented small vesicles of SER were observed in cytoplasm of Sertoli cell. The above changes appeared to be dosage and duration dependent; (2)In the seminiferous tubules of animals receiving CE (1000-2000 ?mol/L testis, 6-14 hr) plus fixation with 10% hypertonic dextrose solutions, usually the germ cells shrinkage and exaggeration of intercellular spaces withint he basal as well asthe adluminal compartments were observed. The tight junction between Sertoli cells were also appeared to be separated by hypertonic action of dextros; (3) The results of tracing experiments showed that lanthanums as tracer could be seen to pass through the Sertoli-Sertoli cell junction of the barrier and enter into the adluminal compartment, the tracer that surrounding the spermatocytes and round spermatids were discernible readily. The above results suggest that cytochalsin E disturbed actin filaments of Sertoli ectoplasmic specialization thus altered the functional integrity of the Sertoli cell barrier. The relationship between the actin filaments and Sertoli cell barrier was discussed.
ABSTRACT
The gene expression of both the mouse plasmocytoma (SP2/0) and the hybrid cells crossed with rat nucleated erythroblasts were detected by in situ hybridization technique using the probes of mouse ?-globin gene and 7 oncogenes (v-Ki-ras, v-H-ras, v-sis, erb-B, v-abl, v-fos, c-myc). After plasmic amplification, DNA was isolated by alkali lysis, purified and recovered, the DNA containing gene fragments were labelled with ~(32)P to become high activity ~(32)P-cDNA probes through nick translation, and the labelled probes were used to detect the gene transcripts in cellular level. The results indicated that: (1) no mouse ?-globin gene transcripts could be detected in the cytoplasm of SP2/0 cells, as well as in hybrid cells within 72 hours after cell fusion, but transcript signals could be observed in hybrid cells from 4th to 26th passages. (2) Active expression of multioncogenes in SP2/0 cells was demonstrated, all the 7 oneogenes tested, except v-sis, were expressed more strongly. On the other hand, the expression of oncogenes in hybrid cells was found to be dramatically decreased, among them, the oncogenes of c-myc and Ki-ras been suppressed completely. After long term of passages (26th subcultures), the expression of c-myc and Ki-ras was still lower than that of SP2/o ceils although in some cases other oncogenes increased in their expression levels. These results confirmed that the multistep carcinogenesis involved multi-oncogenes expression and that the decancerization of tumor cells may be due to the suppression of multi-oncogenes activity as well as to activate the expression of differentiation genes.
ABSTRACT
The changes of the growth characteristics and surface ultrastructure during longterm passages of Wg3h cells that have been transfected with PSV_2-neo (Wg3h-neo) were studied. The results showed that the growth and DNA synthesis rate were evidently higher in the transfected cells than in the parental wg3h cells. The saturation of the transfected cell growth density was also increased, but neither the parental and transfected cells formed cell colony in soft agar medium nor tumor growth in nude mice. There was no significant differences in morphology between the two cell types under light microscopy, however much more microvilli were seen on the transfected cell surface under scanning electron microscopy. Southern blot hybridization analysis indicated that the PSV_2-neo plasmids were integrated into the genome of the target cells. Our results demonstrated that the transfected cells remained as nonmalignant cells although some changes of their growth characteristics and surface ultrastructure appeared.
ABSTRACT
The present study reported the observations with light and electronic micros copy on hybrid cells crossed between rat intermediate or late erythroblasts and mouse SP2/0 plasmocytoma cells. In a short period after fusion, the cell size and the ratio of nuclear heterochromatin in hybrid cells appeared to be increased, but the number of nucleoli, as well as the number of microvilli, finger-like processes, and nuclear cytoplasmic ratio were decreased. Swelling mitochondria, pycnotic nuclei and/or process of enucleation also could be seen in some hybrid cells. The subcul tured hybrid cells were characterized with less microvilli and cellular surface membrane processes, and showing marked changes in nuclear size, as well as the appearance of cytoplasmic vesicles and dense granules in some cells. The observations mentioned above provide morphological and ultrastructural evidences for the regulation of malignant phenotype of hybrid cell model we reported previously. The possible relationship between the deeancerization and the morphological changes of hybrid cell nucleus, cytoplasm and cell surface were briefly discussed.
ABSTRACT
The fine ultrastructure and localization of acid phosphatase in cell ultrastructuralevel of a HGPRT-human promyelocytic leukemia cell mutant(HL-60-AR)arestudied by scanning electron microscopy,transmission electron microscopy,freezeetching,and electron microscopic cytochemistry techniques.The results of theobservation show that the ultrastructural characteristics of HL-60-AR cells aresimilar to that of HL-60 cells.There are microvilli and ridges over cell surface.Thecells have large nucleus with prominent nucleoli,and numerous nuclear pores.Thereare less developed Golgi complex,expanded rough endoplasmic reticulum andabundant polyribosomes.After treatment with retinoic acid(RA)at 10~(-6) mol/L for 5days,HL-60-AR cells differentiate along myeloid pathway and have a decreasednucleocytoplasmic ratio accompanied with nuclear condensation and segmention.A (?)ignificant increase of specific granules is demonstrated.Microvilli of the cellsdisappear,surface features of the treated cells become more irregular and largeprotrusion and blunt pseudopodia appear.Increase of acid phosphatase content localizedon azurophilic granules(lysosomes)and Golgi complex is showed.The application offour kinds of electron microscopic techniques might provide the best way foridentifying cell ultrastructure.