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T C Hsu

Publications and source records attributed to T C Hsu.

At least 145 records · Page 8Linked to original sources
PubMed1986

Chromosome aberrations in mouse bone marrow cells following treatment in vivo with vinblastine and Colcemid.

The present study was undertaken to determine if chemicals that are capable of inducing mitotic arrest and aneuploidy can also induce chromosomal breakage. Two chemicals, vinblastine and Colcemid, were selected to be studied. Their potentially clastogenic effects were investigated in mouse bone marrow cells in vivo. Two doses of vinblastine, 10(-5) M (9 mg/kg) and 10(-6) M (0.9 mg/kg), and one dose of Colcemid 10(-4) M (37 mg/kg), were administered to mice as single intraperitoneal injections. Bone marrow preparations were made at multiple time periods after injections, ie, 17, 24, 48, 72, and 96 hr. Both these agents, at the concentrations tested, induced mitotic arrest of bone marrow cells within 5 hr after injection. In recovering bone marrow cell populations, 2-3 days after drug administration, significantly elevated levels of chromosomal breakage (mainly the chromatid type) were observed. Vinblastine was found to be much more potent than Colcemid. Since both of these agents affect mainly microtubules, their actions to cause chromosomal breakage are likely to be indirect. Several possible clastogenic mechanisms such as interference with DNA synthesis, active metabolites, and cytoplasmic endonucleases are discussed.

Animals↗
PubMed1986

Mitotic inhibition and aneuploidy induction by naturally occurring and synthetic estrogens in Chinese hamster cells in vitro.

We used a predominantly diploid Chinese hamster cell line to test a number of naturally occurring and synthetic estrogens for their ability to arrest cells at metaphase, their potential for allowing anaphase recovery, and their capability of inducing aneuploid progeny. The chemicals employed included diethylstilbestrol, dienestrol, hexestrol, beta-estradiol, ethynylestradiol and estriol. We also tested progesterone, estrone and testosterone in this regard. Only estrogens and their synthetic analogs caused mitotic arrest and aneuploidy, while progesterone, estrone and testosterone did not cause mitotic disturbances. Among the estrogens, DES was the most effective arrestant on a comparative molar basis, whereas dienestrol was most potent over a wide range of concentrations. Estriol was the least potent as an arrestant but was an effective inducer of aneuploidy. The addition of a metabolic activator (S9) did not alter the ability of DES to arrest mitosis. Following the removal of the drugs, cells were able to quickly reorganize a spindle apparatus and enter anaphase. Diethylstilbestrol, dienestrol, hexestrol, beta-estradiol, ethynylestradiol and estriol caused significant increase in aneuploidy within a narrow range of high concentrations in recovering cell populations. Aneuploidy was induced in a non-random manner. Immunofluorescence studies with anti-tubulin antibody indicate that estrogens may have a mechanism of mitotic arrest similar to that of colchicine and colcemid, viz inhibiting the polymerization of tubulin to form microtubules. These data suggest that the interaction between estrogens and microtubules may mediate the induction of aneuploidy in somatic cells. Aneuploidy induction by DES and similar compounds may be related to their carcinogenic potential.

Anaphase↗
PubMed1986

Biochemical characteristics of Edwardsiella ictaluri.

A total of 119 isolates of Edwardsiella ictaluri collected over the last 7 years from several states were biochemically characterized. Although not very reactive biochemically, this bacterium shows a high degree of homogeneity. Differences were found only in the production of gas from formate or from glucose at 37 degrees C and in the production of hydrogen sulfide as detected by lead acetate paper. Analysis of E. ictaluri by year of geographic area indicated that some differences existed, but no clear-cut biotypic variations were found. All isolates studied were capable of degrading chondroitin sulfate, a major component of cartilage, which may be an important virulence factor in the formation of the hole-in-the-head lesion characteristic of infected fish.

Enterobacteriaceae↗
PubMed1985

Response of murine spermatocytes to the metaphase-arresting effect of several mitotic arrestants.

Three mitotic arrestants, colchicine, Colcemid and vinblastine, were evaluated for their effects on producing meiotic arrest in the laboratory mouse. Colchicine is the most effective and its effect is both dose- and time-dependent. Treatment of mice with 40 mg/kg of colchicine for 3 h resulted in drastic improvement of the yield and quality of M-II figures. This treatment did not appear to increase the aneuploidy frequency in M-II's.

Aneuploidy↗
PubMed1985

Differential mutagen susceptibility in cultured lymphocytes of normal individuals and cancer patients.

When cultured human lymphocytes were treated with a radiomimetic chemical bleomycin, metaphase chromosomes from different individuals exhibited a wide spectrum of responses in terms of number of chromatid lesions. This variability is interpreted as the result of capability for DNA repair. Among 100 healthy, normal individuals tested, nearly 60% showed a mean breaks per cell rate in the range of 0.20-0.60, whereas, only 12% showed breaks per cell rates above 1.00. On the other hand, among 75 cancer patients, 60% showed breaks per cell rates above 1.00. It is believed that differential responses to a mutagen have genetic implications. Individuals with DNA repair deficiencies may be more susceptible to carcinogens and, therefore, are more susceptible to neoplastic induction.

Bleomycin↗
PubMed1985

Anti-kinetochore antibodies: use as probes for inactive centromeres.

Application of a modified immunofluorescence technique using an anti-kinetochore serum enables cytogeneticists to obtain quality metaphase spreads and to localize kinetochores. In a patient with a 45, XX, -9, -11, tdic (9p;11p) constitution, we found that the dicentric marker chromosome has an intensely fluorescent kinetochore (no. 11), the functional centromere, and a less intensely fluorescent kinetochore (no. 9), the inactive centromere. The data suggest that in the process of tandem fusion (telomere-telomere between 11p and 9p), the centromere of chromosome 9 was not deleted, but, rather, inactivated.

Antibodies↗
PubMed1984

Antitubulin immunofluorescence studies of spermatogenesis in the mouse.

Immunofluorescence staining techniques, using antibodies against tubulin molecules, have been successfully used with somatic tissue culture cells. Their application to gametogenesis, however, has been more difficult, largely due to the presence of many different cell types in such a preparation. We have circumvented this problem by counterstaining with dilute hematoxylin, a biological stain that shows excellent cellular morphology without affecting the fluorescence of the antibody. We can then photograph the same field, using either ultraviolet light or conventional bright-field microscopy. Using this approach, we have examined the entire progression of murine spermatogenesis, from spermatogonial cells through mature spermatozoa. This technique has been especially valuable in the visualization of the manchette, and has allowed a reassessment of the staging of spermatid development. In the future, the antibody/hematoxylin double-staining approach will allow a more informative examination of the effects of tubulin-active mitotic poisons on mammalian germline cells.

Animals↗
PubMed1984

Surgical treatment of chronic anal fissure. A retrospective study of 1753 cases.

This is a retrospective study of 1753 cases of chronic anal fissures treated by five varying methods over a five-year period from January 1976 to December 1980. Results showed that the incidence of recurrent fissures was higher in those treated by anal fissurectomy with sphincterotomy. There was also a significant difference in operative time, length of hospital stay, patient discomfort, and incidence of urinary retention among these operative methods. Generally, lateral anal sphincterotomy and multiple anal sphincterotomies showed a lesser incidence of these factors. A simpler procedure, such as lateral anal sphincterotomy or multiple anal sphincterotomies, is the treatment of choice for chronic anal fissure. However, a chronic anal fissure associated with symptomatic enlarged hemorrhoids may have a similar result when treated with hemorrhoidectomy and fissurectomy as a combined procedure.

Adult↗
PubMed1984

Subclavian cannulation. Valuable dialysis access alternative.

The subclavian vein was used for temporary dialysis access in 67 patients. There were 733 dialysis treatments performed using a total of 87 catheters during the study period. The catheters were left in place for an average of 24.5 days per patient and 18.9 days per catheter. A mean of 10.9 dialysis treatments per patient, and 8.4 dialysis treatments per catheter were performed. Seven patients expired with their catheters indwelling. None of these deaths were related to the catheter. There were 21 associated catheter complications. Twelve of these catheter complications were corrected by changing the catheter over a guide wire. The technique for catheter insertion, proper catheter care including home care, and complications due to the catheters are discussed. Subclavian catheter dialysis access appears to be a valuable adjunct for dialysis and has replaced the use of Scribner shunts and repeated femoral catheterizations for temporary access in our institution.

Catheterization↗
PubMed1983

Toxicity of a male contraceptive, gossypol, in mammalian cell cultures.

Gossypol, a substance extracted from cotton plants, is a potential male contraceptive. Although human users reported only mild or no side effects, our study found gossypol to be cytotoxic to cultured mammalian cells. A dose dependent decrease in the number of viable cells and mitotic index was demonstrated with both Chinese hamster ovary (CHO) cells and human lymphocytes after the cultures received treatment of gossypol for various durations. Cellular DNA, RNA, and protein synthetic activities were reduced in the presence of gossypol. However, gossypol did not seem to induce chromosome breakage or polyploidy.

Animals↗
PubMed1983

Isolation and preliminary characterization of the synaptonemal complex from rat pachytene spermatocytes.

A method for preparation of the morphologically intact synaptonemal complex from rat pachytene spermatocytes is described. Pachytene spermatocytes were fractionated from rat testicular cells by centrifugal elutriation. Nuclei from fractionated pachytene cells were prepared and extensively digested with micrococcal nuclease. The digested nuclei were sedimented through 20% (w/v) sucrose containing 2 M NaCl by centrifugation. About 10% of total nuclear proteins and 1-2% of total genomic DNA was found to be associated with the residual structure. The residual structure, which contains mainly the synaptonemal complex, but may be still contaminated with other nuclear components including membrane and matrix, was stained with silver and examined under light microscopy. It was found that a silver-staining component of the synaptonemal complex is not grossly different from that in pachytene nuclei not subjected to digestion and extraction. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis revealed that virtually all the proteins in the residual structure are non-histones. The DNA isolated from the residual structure was about 135 base pairs (bp), long. The DNA was end-labeled and hybridized with a large excess of sonicated rat genomic DNA. The hybridization displayed a kinetics virtually identical to that of total nuclear DNA. We also prepared restricted DNA fragments associated with the residual structure. Southern blot analyses using a probe made from a recombinant DNA clone containing the albumin gene revealed that the DNA associated with the residual structure was not enriched (or depleted) in this gene sequence. Our results strongly suggest that (1) the synaptomenal complex may play a structural role to support the chromatin domains inside pachytene nucleus; and (2) a simple common DNA sequence in the chromatin domain is not required for association with the residual structure which contains morphologically intact synaptonemal complex in rat spermatocytes.

Albumins↗
PubMed1983

Cytogenetic assays for mitotic poisons. The grasshopper embryo system for volatile liquids.

The present study demonstrates the usefulness of grasshopper (Melanoplus sanguinipes) embryos for detecting mitotic arrest and anaphase abnormalities induced by volatile liquids. Eight compounds were tested with this system. Embryos in vivo (intact chorions) were suspended in sealed chambers and the agents, in various amounts, were placed on the bottom of the chambers. The agents, after evaporation, filled the ambient air in which the embryos respired. After a period of exposure, individual embryos were fixed for squash preparations to determine the mitotic index (MI) and the ratio of anaphases to metaphases (A/M). If an agent completely arrested mitosis at metaphase, the A/M ratio would be zero and the MI would be elevated if the agent does not prevent interphase cells from entering mitosis. Two common organic solvents, benzene and toluene, and two common anesthetics, halothane and chloroform, were found to be potent mitotic arrestants in the present system. Colchicine-like mitoses (c-mitoses) were observed in embryos after treatment of the above four agents; all of these agents except toluene were found to induce an accumulation of c-mitoses. Amyl acetate, 95% ethanol, deionized water, and camphor (in 10% ethanol) failed to show mitosis-arresting effects on the embryos. Abnormal anaphases with lagging chromosomes and multipolar spindles were observed in embryos which showed partial metaphase block after exposure to concentrations of benzene lower than that required for a complete block. Benzene, toluene, halothane, and chloroform have been implicated as teratogens and carcinogens, but are negative as mutagens, clastogens, and SCE inducers. Thus, the carcinogenic activity of these compounds appears to result from their action on cell division mechanisms.

Animals↗