Biomedical subjects
Publications and source records attributed to T Nishimoto.
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Cultures of ts BN75, a temperature-sensitive mutant of BHK 21 cells, show a gradual biphasic drop in [3H]thymidine incorporation together with an accumulation of cells having a G2 DNA content when incubated at 39.5 degrees. However, when higher (41 degrees - 42 degrees) nonpermissive temperatures were used, the major block was in S-phase DNA synthesis. The cultures of ts BN75 shifted to 42 degrees at the start of the S phase, cell-cycle progress was arrested in the middle of S, while under these conditions wild-type BHK cells underwent at least one cycle of DNA synthesis. When ts BN75 cells growth-arrested at high temperature with a G2 DNA content were shifted to the permissive temperature (33.5 degrees C), the restart of DNA synthesis preceded the appearance of mitotic cells. These data suggest that the ts defect of ts BN75 cells might affect primarily the S phase of the cycle rather than the G2 phase.
The nutritional value of N-acetyl-L-tryptophan (NALT) given intravenously was examined in unrestrained adult rats. They were given solutions of 4% Vuj pattern amino acids, 24.5% glucose, vitamins and electrolytes intravenously for 10 days. They were divided into three groups; one group was then injected intravenously with complete amino acid solution (T group), one with tryptophan-free amino acid solution (TF group) and one group with complete amino acid solution but with NALT instead of tryptophan (NALT). The biological value of the NALT group was 49.6; this value corresponded to 90% of that of the T group. Excretion of injected amino acids totalled about 2.0 to 3.0% in this experiment. The effects of NALT on carcass composition, certain blood constituents and tryptophan pyrrolase activity in the liver were also examined.
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A total of 735 human serum samples were tested against isolated porcine ova for detection of autoantibodies to zonae pellucidae by the specific method reported previously using indirect immunofluorescence. Positive fluorescence was found in 13 of 175 samples (7.4%) from patients with unexplained infertility, in 2 of 122 samples (1.6%) from patients with proven etiology of infertility, but in none of 141 samples from age-matched control subjects (fertile women and men). There was an age difference in the incidence of positive reactions: 4 of 156 samples (2.6%) from women over 40 years old were positive in contrast to only 1 of 159 samples (0.6%) from women under 40 years old. Although autoantibodies to zonae pellucidae may be produced during the aging process, the observed high incidence in unexplained infertility suggests an etiologic association of the antibody with the disease when produced in younger women.
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In vitro sensitivity of an established cell line from human urinary bladder cancer to various chemotherapeutic agents was determined by 14C-leucine incorporation into the target cells. Of 12 drugs tested, Carboquone, Neocarzinostatin, Actinomycin D, Adriamycin, Mitomycin C and Chromomycin A3 produced intensive cytotoxic effects, while Thio-Tepa, Bleomycin, 5-Fluorouracil and Vincirstine were less cytotoxic, Intravesical instillation of Carboquone, one of the most toxic agents in vitro, resulted in complete or partial tumor remission in 6 of 9 patients with bladder cancer. Prophylactic effects of periodic intravesical Carboquone were also indicated in 7 of 8 patients who had experienced recurring superficial bladder tumors.
Human antibodies to porcine erythrocytes were found to bind to porcine but not to human zonae pellucidae, whereas human isohemagglutinins bound to human but not to porcine zonae. On the basis of the binding behavior of agglutinins, it was found that the immunofluorescence of porcine zonae produced by selected sera from infertile women was due to an antibody of different specifity from that which agglutinated pig red blood cells. However, no serum component other than heteroagglutinin was contained in selected sera from control subjects which fluoresced porcine zonae. Since the component was present in the immunoglobulin G fraction, bound to human zonae, and was reactive with zona-specific antigen(s), it was judged an autoantibody to zonae. Thus a method for specific detection of autoantibodies to zonae has been developed by indirect membrane immunofluorescence using porcine ova as targets.
Microencapsulated Mitomycin C with ethylcellulose was infused into isolated dog kidneys through the renal artery. The capsules were lodged mainly at cortico-medullary junction, where the drug was released from the capsules. Vascularity of kidney was reduced moderately.
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Of 52 serum samples from infertile women tested against isolated porcine oocytes by immunofluorescence, 8 produced intense reactions in zonae pellucidae, while only one of 52 sera from control subjects showed the reaction. Autoantibodies to the zona may be present in these women.
A procedure for the isolation of temperature sensitive mutants of BHK cells is described. Mutagenized cells were synchronized in G1 by serum starvation at 33 degrees, and, following release, shifted to 37.5 degrees in the presence of FUdR, to kill cells entering the DNA synthetic phase. Eight independently mutagenized series of cells were carried through four cycles of this selection, and surviving cells were tested for ability to grow at 33 degrees and 39.5 degrees after each cycle. The results suggest that such procedure is effective in enriching for non-leaky ts mutants and favors the isolation of mutants which at 39.5 degrees are inhibited in the processes necessary for DNA synthesis and lose viability rapidly. The effectiveness of repeated selection cycles and the general characteristics of the ts mutants isolated by this method were also evaluated.
A particular technique designed to select for temperature-sensitive DNA-synthesis mutants of BHK cells has yielded primarily a class of mutants which do not show complementation in cell hybrids.
A temperature-sensitive mutant of BHK, designated ts BN-2, shows a rapid drop in 3H-thymidine incorporation along with accumulation of the cells in the G1 phase of the cycle when asynchronous cultures are shifted from 33.5 degrees C to the nonpermissive temperature of 39.5 degrees C. Synchronized cultures of ts BN-2 cells did not enter DNA synthesis when shifted up in G1. Shift-up of cultures at the beginning of the S phase resulted in an approximately normal rate of DNA synthesis for about 2 hr. The rate of DNA synthesis then quickly declined, and the cells became arrested in mid-S after completion of approximately 0.5 rounds of DNA replication. At the same time, the majority of the cells were observed to lose the nuclear membrane and displayed premature chromosome condensation. These events were followed by the appearance of cells containing several micronuclei and eventual cell disruption and death. The nonpermissive temperature appeared to have no effect on either the elongation of short fragments of DNA or the execution of mitosis after the completion of the S phase under permissive conditions. The ts defect in this mutant may directly limit the initiation of DNA synthesis or alter the regulation of chromatin condensation.