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Biomedical subjects

M Ohashi

Publications and source records attributed to M Ohashi.

At least 505 records · Page 28Linked to original sources
PubMed1979

A comparison of the ganglioside distributions of fat tissues in various animals by two-dimensional thin layer chromatography.

The ganglioside distributions of various fat tissues from human, rabbit, rat, mouse, chicken and frog were compared with pig adipose gangliosides by two-dimensional thin layer chromatography. It was found that there is a remarkable species variation in ganglioside distribution, especially in the composition and relative concentration of complex gangliosides. Differing from pig adipose tissues, those of human, rabbit, rat, mouse, chicken, but not frog, contained GM3 as a most abundant ganglioside. The data for human, rabbit and chicken indicated a simple distribution of only NeuAc-type gangliosides, while those for rat and mouse indicated a rather complicated pattern containing both NeuAc- and NeuGc-type gangliosides. The ganglioside pattern of the frog fat body differed markedly from those of mammalian fat tissues because of the presence of three different, unusual monosialosylgangliosides as major components. In other respects, a substantial amount of disialosylgangliosides was commonly found in all animal fat tissues.

Adipose Tissue↗
PubMed1979

Fate of newly synthesized histones shortly after interruption of DNA replication.

The synthesis and association of histones with chromatin were studied using MH-134SC cells in suspension culture. Cultures containing approximately equal numbers of cells were pulse-labeled with [3H]lysine at various times after the interruption of DNA synthesis with hydroxyurea. Each culture was mixed with a fixed volume of a culture generally labeled with [14C]lysine at the time of harvesting. Acid-soluble proteins extracted from different subcellular fractions of cells labeled under various conditions were compared by electrophoresis on polyacrylamide gels containing acetic acid and urea. All types of chromatin histones were labeled nearly equally as [14C]marker histones by a 15 min pulse under normal conditions, except that a considerable portion of pulse-labeled H4 was in highly acetylated forms. Addition of hydroxyurea at the start of the pulse markedly reduced the labeling of H3 and H4, but affected the labeling of the other histones only slightly. When DNA synthesis was inhibited before the start of the pulse, labeling of all histones decreased significantly. The addition of hydroxyurea was found to cause transient accumulation of newly synthesized proteins in the cytoplasmic soluble fraction; these were characterized as H3 and H4 from their metabolic properties and their electrophoretic mobilities on sodium dodecyl sulfate-polyacrylamide gels. The results suggest that association of newly synthesized H3 and H4 histones is closely coupled with ongoing DNA replication. The implications of the results for the mechanism of formation of new nucleosomes are discussed.

Cell Line↗
PubMed1979

A human chorionic gonadotropin-specific antiserum against synthetic peptide analogs to the carboxyl-terminal peptide of its beta-subunit.

A chemically synthesized Na-acetyl-triacontapeptide analogous to the carboxyl-terminal region (residues 116--145) of hCG beta-subunit was conjugated to bovine thyroglobulin. This synthetic antigen was used to immunize five rabbits; one of these rabbits (H-114) generated a useable antiserum. The binding properties of this antiserum were compared extensively to a well characterized antiserum (H-93) against the natural tricosaglycopeptide (residues 123--145) of desialylated hCG beta-subunit conjugated to bovine serum albumin. The two antisera showed nearly identical immunological specificities and sensitivities when examined in a conventional RIA system. These similarities included: 1) antibody recognition sites residing at the carboxyl-terminal pentadecapeptide region; 2) binding neither [125I]iodo-hLH nor [125I]iodo-oLH; and 3) lack of neutralizing capability against the biological activity of hCG in vivo. However, synthetic pentadeca or longer peptides are twice as potent in inhibiting 125I]iodo-hCG binding to H-114 than to H-93. Synthetic peptides may provide a superior means of generating antisera capable of distinguishing hCG from human LH, since they can be obtained more easily in large quantities than analogous purified natural fragments and because peptides of synthetic origin avoid the risk of contamination from strongly antigenic regions of the native molecules. Such hCG-specific antisera may have extensive application in RIA systems and fertility control, where selective binding to hCG but not human LH is desired.

Binding, Competitive↗
PubMed1979

Induced ischemia: means of prediction of demarcation line of necrosis after electrical injury. An experimental study on rabbit ear.

Necrosis due to an electrical injury extends by progressive obstruction of blood vessels. Means of inhibiting expansion of necrosis and predicting early the demarcation line after an electric injury were studied in the local electric injury of a rabbit ear produced by application of an electric current of 50 Hz, 1800 V for 1 sec between the right ear and the right posterior leg. Although no effective method of inhibiting expansion of necrosis was obtained, a method of predicting a demarcation line of necrosis was obtained by inducing ischemia of the ear early after the application of an electric current. From three hours to three days after the application of the electric current, ischemia of the ear was induced by compressing it between a pair of blood pressure cuffs at a pressure of 300 mmHg. As a result, the area proximal to the expected demarcation line of necrosis became white by ischemia, while the peripheral part remained dark red because of thrombi, and the expected demarcation line was clearly observed. Two to three weeks after the application of the electric current, the ear almost invariably fell off at this expected line. Therefore, in the electric injury of the hand, it can be distinguished clinically whether or not the area will become necrotic by inducing ischemia from the tips of the fingers to the upper arm early after the electric injury.

Animals↗
PubMed1979

[Ossification of the posterior longitudinal spinal ligament--comparative studies with computerized tomography (author's transl)].

Ossification of the posterior longitudinal spinal ligament (OPLL) was characterized by calcified longitudinal band along the posterior margin of vertebrae, but it has not been possible to know how the cord is compressed within the narrowed spinal canal. Our neuroradiological studies based on CT-view of the 15 cases of OPLL suffering from various degree of myelopathy revealed: 1) Computed tomography precisely delineated shape of OPLL, which was quite polymorphic, like mushroom, irregular cubic and round. OPLL ranged more than two vertebrae was not uniform, but exhibited different configuration at each level. 2) OPLL at lower cervical and higher thoracic regions was difficult to diagnose by conventional lateral roentgenograms, but CT-scan demonstrated clearly whole extent of OPLL. 3) obliteration ratio of the affected spinal canal was calculated on CT-scan. Cases showing severe myelopathy, such as quadriparesis and neurogenic bladder, presented spinal canal stenosis of more than 30%. Spondylosis were concomittant roentgenographic findings on 13 cases of OPLL (87%). However, spondylotic changes responsible to the myelopathy were seen on only three cases. In these case, the obliteration ratio by ossificated ligament was lower than 26%. On conclusion, computed tomographic views of OPLL gave us more detailed information about the stenotic spinal canal and found to be essential examination when considering operative intervention.

Aged↗
PubMed1978

Fractionation of unfixed chromatin by buoyant-density centrifugation in gradients containing 3-iodo-1,2-propanediol and metrizamide.

Buoyant-density centrifugation of unfixed chromatin has been performed in a newly devised medium containing 3-iodo-1,2-propanediol and metrizamide. Chromatins were obtained from isotopically labeled mouse hepatoma cells in suspension culture, either grown normally or density labeled in a medium containing bromodeoxyuridine, by mild digestion of isolated nuclei with micrococcal nuclease. When a mixture of normal and density labeled chromatin, marked with [14C]thymidine and [3H]bromodeoxyuridine, respectively, was centrifuged in the medium, chromatin peaks represented by labeled DNA were resolved to the extent expected from their separate banding profiles. Centrifugation of an equivalent chromatin mixture labeled with [14C] and [3H]lysine, respectively, also yielded resolution of chromatin peaks represented by labeled proteins. Only small amounts of labeled proteins were dissociated from chromatin in the gradient medium. Labeled proteins recovered from the gradient fractions were analyzed by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. The results suggested that most of the histones remained associated with the original stretches of DNA during the centrifual fractionation period. Essentially all of the dissociated proteins were found to be non-histone proteins.

Bromodeoxyuridine↗
PubMed1978

Preferential association of newly synthesized H3 and H4 histones with newly replicated DNA.

The assembly of newly synthesized histones into chromatin during replication of MH-134SC cells was studied. Cells pulse-labeled with iododeoxyuridine and [3H]lysine were mixed with an equivalent number of normal cells labeled with [14C]lysine. Nuclease chromatin obtained from pooled cells was fractionated by buoyant-density centrifugation in a gradient containing Metrizamide and 3-iodo-1,2-propanediol. Histones extracted from heavy and normal chromatin regions of the gradient were fractionated by acid-urea gel electrophoresis, and 3H/14C ratios of individual histones were compared. The results showed highly preferential association of newly synthesized H3 and H4 with newly replicated DNA.

Cell Line↗
PubMed1978

[Enterotoxin].

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Animals↗
PubMed1978

Antibodies to herpesvirus type 1 and type 2 among Japanese cervical cancer patients.

Antibodies to herpesvirus type 1 and type 2 were examined in 69 Japanese females with cancer of uterine cervix, which included cases of cervical dysplasia (7 cases), carcinoma in situ (9 cases), and invasive carcinoma (53 cases), and 112 matched controls. The presence of antibodies to type 2 virus was 42% in cervical dysplasia, 11% in carcinoma in situ, and 28% in invasive carcinoma, while such was 15% in matched controls. Mean antibody titer in log10 was 2.12 to type 1 and 1.65 to type 2 in women with invasive carcinoma, and 2.14 to type 1 and 1.67 to type 2 in the matched controls. The findings presented here did not support an association of type 2 virus infection with the occurrence of cervical cancer.

Adult↗