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Biomedical subjects

Y Kano

Publications and source records attributed to Y Kano.

At least 271 records · Page 15Linked to original sources
PubMed1985

Histological development of bovine abomasum.

The histological development of the bovine abomasum during fetal and neonatal periods was studied. The abomasum in a fetus of 2.3 cm in length (estimated to be 1 month old) was a separated compartment situated to be caudo-ventral to the primordium on the median plane. On the later stages, the primitive stomach became distinctly separated into rumen, reticulum, omasum and abomasum. The epithelium of abomasum was pseudostratified histologically, consisting of cells low differentiation. The stomach in a fetus of 13-14 cm in length (estimated to be 3 months old) displayed the morphological feature with nearly same proportion as an adult stomach. In this stage, abomasal epithelium had a shape of simple column and also formed gastric pits. Pyloric gland cells could be recognized earliest of all the gastric exocrine cells in fetuses of 16-18 cm in length (estimated to be 3-4 months old). Mucous neck cells could be found in fetuses 43-45 cm in length (estimated to be 5-6 months old). Pyloric gland cell and mucous neck cell contained neutral and sialo- or sulfo mucosubstances in neonates. Chief cells, could be noticed in fetuses 58-65 cm in length (estimated to be 6-7 months old), and were devoid of demonstrable mucosubstance as well as parietal cells. Main abomasal gland cells began to develop to increase rapidly in number in the latter half period of gestation. All the types of gastric cells became to be present and mature in form at birth.

Abomasum↗
PubMed1985

Effects of nifedipine on insulin secretion and glucose metabolism in rats and in hypertensive type 2 (non-insulin dependent) diabetics.

The effects of nifedipine (Adalat) on glucose metabolism and insulin release were studied in rats and in patients with type 2 diabetes mellitus complicated with hypertension. 1. In rats, 2.5-50 micrograms/kg of intravenous nifedipine reduced glucose tolerance and insulin release after intravenous glucose in a dose related fashion, although fasting blood sugar and insulin were not affected at 50 micrograms/kg of nifedipine. 2. Daily 20 to 60 mg of oral nifedipine for 12-75 weeks to 14 type 2 diabetics with hypertension did not affect their fasting blood glucose or hemoglobin A1. Mean glucose tolerance curve after the treatment was significantly ameliorated, although insulin response during the oral glucose loading did not show any significant change. Those results suggest firstly that there may be a difference in insulinopenic effect of nifedipine between the species, and secondly that long-term administration of nifedipine produced no adverse influence on glucose metabolism in type 2 diabetics.

Aged↗
PubMed1985

Mechanisms of human cell neoplastic transformation: X-ray-induced abnormal clone formation in long-term cultures of human diploid fibroblasts.

Early passage cultures of a strain of normal human diploid fibroblasts were exposed to various doses of X-rays. The cells were serially passaged and followed throughout their life span in vitro. G-banded metaphase chromosome preparations were examined at each subculture to determine the presence of abnormal clones, i.e., groups of cells bearing identical chromosomal rearrangements. It was found that X-irradiation induced random chromosomal rearrangements which persisted throughout the life span of the cells. No abnormal clones were observed among the progeny of four nonirradiated cultures, nor in seven of nine cultures exposed to single radiation doses. On the other hand, multiple abnormal clones emerged among the progeny of cells in all five cultures exposed to multiple sequential radiation doses (three doses of 400 or 600 rads each). Evidence of clonal expansion and attenuation and of clonal succession during serial passaging occurred in these populations. In several cases, these clones expanded to include most of the cell population before the cultures became senescent. These findings are discussed in terms of their possible role in the transformation of human diploid cells by radiation.

Cell Transformation, Neoplastic↗
PubMed1984

DNA interstrand cross-linking, repair, and SCE mechanism in human cells in special reference to Fanconi anemia.

The relation of DNA cross-linking and repair to sister chromatid exchange (SCE) formation was studied in normal human, Fanconi anemia (FA), and xeroderma pigmentosum (XP) cells. Despite a hypersensitive lethality response in FA cells, the SCE induction rates by mitomycin C (MMC), trimethylpsoralen (TMP)-light, cisplatin, and diepoxybutane were twice as high as in normal cells. For MMC, the induced SCE frequency in normal cells was reduced in a biphasic fashion with a repair incubation time (the first decline t1/2 = 2 hr; the second t1/2 = 14-18 hr) which corresponds exactly to the molecular kinetics of cross-link and monoadduct removal. However, FA cells lack the first half-excision process and exhibit a lack of the first rapid decline SCE component. The slow decline component is present, and a higher SCE frequency is observed 24 to 48 hr after treatment. By contrast, XP cells capable of the half-excision process reveal the first rapid decline component, followed by an extremely slow second-reduction component (t1/2 = 48 hr) due to defective monoadduct repair. The endoreduplication-SCE method revealed that rates of both twin (first cycle) and single (second cycle) SCE formations by MMC and TMP-light were higher in FA cells than in normal cells. These results indicate that cross-links remaining unrepaired induce SCEs as do monoadducts. The probabilistic SCE induction occurs at a rate of 1 SCE per 35 MMC cross-links in FA cells. Further, a non-SCE-forming tolerance mechanism also operates in hypersensitive FA cells. These molecular and cytogenetic results allow us to construct a new probabilistic model for cross-link-induced SCE into which the replication-fork model, random cross-link transfer to both chromatids, and chromatid breakage-reunion are incorporated.

Anemia, Aplastic↗
PubMed1984

Isolation and characterization of nucleoid proteins from Escherichia coli.

Of the molecular species of proteins associated with the nucleoids of Escherichia coli cells, those with relatively high affinity to bind to DNA were isolated and characterized. Seven classes of nucleoid proteins with molecular weights of 9,000, 17,000 (two molecular species), 22,000, 24,000, 27,000 and 28,000 were isolated at more than 90% purity or were partially purified. On the basis of its amino acid composition and other chemical properties, the 9,000 dalton protein was identified as HLP II (or HU protein or BH2) (Pettijohn 1982; Rouvière-Yaniv and Gros 1975; Varshavsky et al. 1978). The 17 K protein consisted of two molecular species and one of these, 17 K (a) protein, seemed to be identical with HLPI (or protein 1 or BH1) reported previously (Pettijohn 1982; Varshavsky et al. 1977; Varshavsky et al. 1978). The 26 K protein was identical to the 22 K protein (Kishi et al. 1982). The 27 K protein showed immunological cross-reactivity with the antibody for histone H2A and was thus identified as the H protein reported previously (Hübscher et al. 1980). Two basic proteins, 9 K and 17 K(a), showed relatively high binding affinities to DNA, while the 28 K protein showed moderate binding affinity. The biological significance of these nucleoid proteins, which constitute a family of proteins participating in formation of the nucleoid structure, is discussed.

Bacterial Proteins↗
PubMed1984

Transcription of the trpR gene of Escherichia coli: an autogeneously regulated system studied by direct measurements of mRNA levels in vivo.

The expression of the trpR gene of Escherichia coli was investigated by measuring trpR messenger RNA levels in vivo under various physiological conditions. Trp repressor, when present, led to significant decreases in the amount of trpR message produced; this effect was enhanced by providing excess L-tryptophan to the system. In the absence of Trp repressor, no changes in trpR message levels were observed under any of the conditions employed. Sedimentation profiles of trpR mRNA revealed a single species under all circumstances. These results suggest that autogenous repression alone acts to regulate transcription of the trpR gene. The activity of the trpR promoter in vivo was evaluated using a trpR-lacZ operon fusion. Very good agreement was found between relative promoter activity and trpR message levels under all experimental conditions.

Bacterial Proteins↗
PubMed1984

Sarcophagine (beta-alanyl-L-tyrosine) synthesis in the fat body of Sarcophaga peregrina larvae.

The fat body of Sarcophaga peregrina larvae was found to have activity for synthesis of sarcophagine (beta-alanyl-L-tyrosine). This activity was due to a soluble enzyme (sarcophagine synthetase) that requires Mg2+ and ATP as cofactors. The enzyme activity decreased significantly after puparium formation and no sarcophagine synthesis was detected when fat body from white pupae was incubated in vitro with 3H-beta-alanine. This apparent loss of sarcophagine synthesis was found to be partly due to peptidase, which was induced in the fat body after puparium formation. The activity of sarcophagine synthetase itself in the lysate of pupal fat body, however, was found to be significantly lower than that in the lysate of larval fat body, suggesting the presence of a developmentally regulated mechanism of sarcophagine production.

Adenosine Triphosphate↗
PubMed1984

Production of monozygotic mouse twins from microsurgically bisected morulae.

Mouse monozygotic twins were produced by bisection of the compacted morulae and transfer of the pairs of half-embryos after culture in vitro. The compacted morulae (about 16 cells) were microsurgically bisected, using a fine glass needle attached to a micromanipulator, without any supporting micro-instruments, after pretreatment for zona-softening and decompaction. About 80% of the morulae were bisected without visible cell damage. After 20 h in culture, the half-embryos were classified morphologically as eu-blastocysts, pseudo-blastocysts, or trophectodermal vesicles or non-integrated forms. After culture of 131 pairs of bisected morulae, 75 (57.3%) pairs of eu-blastocysts, 20 (15.3%) pairs comprising a eu-blastocyst and pseudo-blastocyst, and 9 (6.9%) pairs of pseudo-blastocysts, were obtained. The pseudo-blastocysts were considered to be derived from half-morulae in which some blastomeres were destroyed or dissociated as a result of micromanipulation. From 30 pairs of eu-blastocysts transferred to 21 recipients, 5 twin fetuses on Day 17 (18 pairs/9 recipients) and 3 twin male young (12 pairs/12 recipients) were obtained. Survival rate of the twin-embryo pairs was 27.8% at autopsy and 25.0% at term. None of the 20 pairs of pseudo-blastocysts transferred to 10 recipients gave rise to normal conceptuses.

Animals↗
PubMed1984

Changes in plasma concentrations of LH, progesterone and oestradiol in relation to the occurrence of luteolysis, oestrus and time of ovulation in the Shiba goat (Capra hircus).

Luteolysis in Shiba goats was spontaneous (N = 5) or induced by prostaglandin F-2 alpha (N = 5). Blood sampling and the test for oestrous behaviour were carried out at 2-h intervals, and the time of follicular rupture (ovulation) was determined by culdoscopic observations performed every 2 h around the periovulatory period. In both groups plasma LH concentrations showed a temporary but significant increase during the abrupt fall in plasma progesterone concentrations at luteolysis. This LH rise may be responsible for the preovulatory development of antral follicles and the increase in oestradiol secretion from them. The total number of antral follicles (spontaneous luteolysis 3.6 +/- 0.6, induced luteolysis 4.2 +/- 0.7; mean +/- s.e.m.) and the number of ovulations (1.8 +/- 0.4, 2.4 +/- 0.2) did not differ significantly between the two groups. There was also no significant difference in the timing of oestrus, LH surge and ovulation following the two modes of luteolysis. The interval from luteolysis to the peak of the LH surge averaged 65 h (range 56-72 h). The period of oestrous behaviour coincided with the acrophase of the LH surge and lasted for 22 h (12-28 h). Ovulations occurred 21 (16-24) h after the LH peak and 7 (2-12) h after the end of oestrus.

Animals↗
PubMed1984

Effects of leucovorin and methylcobalamin with N2O anesthesia.

Results of the deoxyuridine suppression test, a good marker for defining biochemical megaloblastosis caused by deficiency of folate and vitamin B12, became abnormal (greater than 10%) after 6 hours of administration of nitrous oxide anesthesia. 5-Formyltetrahydrofolate and methylcobalamin administration during nitrous oxide anesthesia have no remarkable effect on the correction of deoxyuridine suppression test values. On the other hand, 5-formyltetrahydrofolate and methylcobalamin administrated at the end of nitrous oxide anesthesia corrected the abnormal deoxyuridine suppression test values nearly to normal range within 1 hour.

Bone Marrow↗
PubMed1984

Fine structure of developing gastric parietal cells in the bovine abomasum.

Developmental changes in the fine structure of gastric parietal cells were studied in bovine fetuses and neonates. Definitive parietal cells first appeared as non-granular light cells at five months of fetal age (in a 48 cm long fetus). At this age they had a microvillous apical surface and cytoplasmic vesicles which accumulated at the apex. Intracellular canaliculi appeared with an increase in mitochondria at six to seven months of fetal age. Fully differentiated parietal cells were present from the eighth month of gestation. At birth they were similar in appearance to those of the adult abomasum.

Abomasum↗
PubMed1984

Persistence of X-ray-induced chromosomal rearrangements in long-term cultures of human diploid fibroblasts.

As part of a long-term study of mechanisms of human cell neoplastic transformation, we have examined the change in the frequencies of X-ray-induced chromosome rearrangements in density-inhibited human foreskin fibroblasts as a function of subculture time. In nonproliferating cells, the frequency of chromosomal aberrations declined within 24 to 48 hr but still remained at a relatively high level up to 43 days after irradiation. Aberrations disappeared rapidly, however, when the cells were allowed to proliferate, indicating that these lesions are lethal to dividing cells. The frequency of induced translocations, as determined by analysis of G-banded karyotypes, was dose dependent and remained stable up to 20 mean population doublings after irradiation. When subculture of density-inhibited cultures was delayed for 4 hr after irradiation (confluent holding), the frequency of chromosomal aberrations in the first mitosis declined, whereas the translocation frequencies at later passage were elevated as compared with cells subcultured immediately. This correlates with the reported increase in the frequency of transformation under similar conditions. These findings support the hypothesis that chromosomal rearrangements induced by DNA damage may be involved in the initiation of cancer.

Cell Line↗
PubMed1983

5-methyltetrahydrofolate-related enzymes and DNA polymerase alpha in normal and malignant hematopoietic cells.

The activities of 5-methyltetrahydrofolate (5-CH3-THF)-related enzymes [5-CH3-THF homocysteine methyltransferase and 5,10-methylenetetrahydrofolate (5,10-CH2-THF) reductase] and DNA polymerase alpha were measured in normal and malignant hematopoietic cells. The 5-CH3-THF homocysteine methyltransferase activity was significantly correlated with 5,10-CH2-THF reductase activity, indicating that the hematopoietic cells with active biosynthesis of tetrahydrofolate from 5-CH3-THF also actively synthesize 5-CH3-THF from 5,10-CH2-THF. The activities of 5-CH3-THF-related enzymes had a tendency to be high in lymphoid cells and low in myeloid cells, and were not correlated with the percentage of blasts and immature cells in the samples examined. Fairly good correlations were observed among these three enzymes in non-malignant bone marrow cells. However, the activities of two of the enzymes correlated only weakly overall with DNA polymerase alpha activity in normal and malignant hematopoietic cells. Generally speaking, DNA polymerase alpha activity correlated well with the percentage of blasts and immature cells in the samples examined.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗