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Biomedical subjects

K Shinohara

Publications and source records attributed to K Shinohara.

At least 253 records · Page 14Linked to original sources
PubMed1992

Circadian rhythms of vasopressin content in the suprachiasmatic nucleus of the rat.

The suprachiasmatic nucleus (SCN) of the anterior hypothalamus contains a circadian pacemaker in mammals. We determined the circadian profiles of arginine-vasopressin (AVP), a major peptide in the dorsomedial SCN, in rats under light-dark (LD), constant dark (DD) and constant light (LL) conditions. Under LD conditions, AVP levels in the SCN showed circadian rhythmicity with a peak at early light phase and a broad trough during the dark phase. This rhythm in the AVP contents was maintained even after 14 days of free-running under DD conditions and 3 days under LL conditions. These circadian patterns of AVP are similar to those of somatostatin, another peptide in the dorsomedial SCN. This indicates a common mode of regulation for peptides in this subfield of the SCN.

Animals↗
PubMed1992

Environmental dose assessment for low-level radioactive effluents discharged from Tokai reprocessing plant.

In the normal operation of the Tokai reprocessing plant, low-level radioactive effluents are discharged to the atmosphere and the ocean under rigid control. Radiation exposures to the population around the plant have been estimated for potential pathways with site-specific parameters such as food consumption, concentration factors of marine organisms, and meteorological conditions. External exposures to a radioactive cloud and internal exposures from inhalation and oral intake of radionuclides are evaluated for airborne effluents. External exposures to a contaminated fishing net and fishing boat are considered pathways for fishermen. External exposure to a contaminated beach and internal exposure via oral intake of marine products are evaluated for liquid effluents. Since the plant began operation in 1977, estimated effective dose equivalents for the public have been less than the annual effective dose equivalent limit of 0.1% recommended by the International Commission on Radiological Protection (1977).

Air Pollution, Radioactive↗
PubMed1992

Biochemical characteristics of thylakoid membranes in chloroplasts of dark-grown pine cotyledons.

Japanese black pine (Pinus thunbergii) cotyledons were found to synthesize chlorophylls in complete darkness during germination, although the synthesis was not as great as that in the light. The compositions of thylakoid components in plastids of cotyledons grown in the dark and light were compared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of polypeptides and spectroscopic determination of membrane redox components. All thylakoid membrane proteins found in preparations from light-grown cotyledons were also present in preparations from dark-grown cotyledons. However, levels of photosystem I, photosystem II, cytochrome b([ill])/f, and light-harvesting chlorophyll-protein complexes in dark-grown cotyledons were only one-fourth of those in light-grown cotyledons, on a fresh weight basis. These results suggest that the low abundance of thylakoid components in dark-grown cotyledons is associated with the limited supply of chlorophyll needed to assemble the two photosystem complexes and the light-harvesting chlorophyll-protein complex.

Journal Article↗
PubMed1992

Image blurring by thermal diffusion in the observation of hydrated biomolecules with soft X-ray microscopy.

A simple model is presented for the estimation of image blurring in X-ray microscopy of biological specimens in a hydrated environment. The model is essentially based on thermal diffusion of an object to be imaged. The degree of image blurring by diffusion depends on the following situations of the object. The object is free from, is tightly fixed to, or is partially connected to the surrounding structures. The proper imaging time required to achieve a given resolution in X-ray microscopy of biological structures was estimated with the present method. The results suggest that imaging time shorter than 3 msec (free) to 1.4 sec (tightly fixed) is required for the observation of a cell (30 microns in diameter) at the resolution of 100 nm. The model is also applicable to a fragmented object caused by imaging X-rays.

Cell Nucleus↗
PubMed1992

Staging of prostate cancer. Accuracy of transrectal ultrasound enhanced by prostate-specific antigen.

Transrectal ultrasound (TRUS) has shown some promise in the staging of prostate cancer, while prostate-specific antigen (PSA) alone is insufficient. By combining prospective TRUS evaluation with retrospective PSA analysis, we demonstrated an increased accuracy of this combined staging method over TRUS alone. In 48 men undergoing radical prostatectomy, TRUS was performed and PSA measured pre-operatively. On the basis of TRUS, tumours were classified as contained or uncontained. An "expected" PSA value was then calculated for each patient as follows: K x volume of hypoechoic area +0.07 x prostate volume where K = 2.1 if the combined Gleason score of the initial biopsy was > or = 7, or 4.2 if the score was < or = 6. If a patient's pre-operative PSA value was less than or equal to the expected PSA, his tumour was judged to be contained. Staging by both TRUS and PSA was combined, so that if the tumour was judged uncontained by either parameter, the combined prediction was uncontained. Results of the combined staging were: sensitivity 84%, specificity 82%, positive predictive value 94%, negative predictive value 60%, accuracy 83%. This PSA formula, which takes into account the size and grade of the lesion rather than an arbitrary cut-off value, enhances the local staging of prostate cancer by TRUS.

Aged↗
PubMed1992

[A case of complete response of locally advanced breast cancer to arterial infusion chemotherapy: cannulation through the right femoral artery and combined use of G-CSF].

We reported a case of locally advanced breast cancer who was cannulated into the right internal thoracic artery through the right femoral artery by Seldinger's method for intra-arterial chemotherapy and obtained good results. In general, aggressive chemotherapy is often accompanied by bone marrow suppression necessitating discontinuation of chemotherapy. However, this patient recovered from this complication by G-CSF. It was suggested that Seldinger's method is suitable for locally advanced breast cancer and that G-CSF has an immediate effect of bone marrow suppression caused by aggressive chemotherapy.

Administration, Oral↗
PubMed1992

[Simple method for measurement of erythrocyte osmotic fragility].

We developed a simple and quantitative method for determination of erythrocyte osmotic fragility, which is based on a logarithmic linearization of osmotic fragility curve and a calculation of three parameters, that is, C50 (the osmolarity causing 50% hemolysis), beta (the slope of the curve) and H (% hemolysis before treatment). By making use of personal computer program, calculation of the parameters and print-out of reports are automated. As the results, it takes only 30 min to finish all procedure. This method is very useful particularly for the laboratory screening of hereditary spherocytosis.

Humans↗
PubMed1992

[Clinical application of data measured by automated blood cell counter].

Rapid progress has been made in automated blood cell counting techniques using several kinds of apparatuses based on different mechanisms of measurement. We report a method of clinical application of the measurements made by an automated blood cell counter in the diagnosis and treatment of diseases, and discuss its usefulness, and its weaknesses that require improvement.

Blood Cell Count↗
PubMed1992

[Intra-arterial infusion chemotherapy with side-hole catheter for primary and metastatic liver, bile duct, and pancreas cancers].

Dislodgement and obstruction of catheter inserted into the artery are great hazards for the hepatic artery infusion chemotherapy. To prevent dislodgement, a new Anthron-coated catheter with a side hole was applied for the treatment of 32 patients with primary and metastatic liver cancer, bile duct cancer and pancreas cancer. The tip of the catheter was advanced deep into the gastroduodenal artery, proper or right hepatic artery, or splenic artery. Anti-cancer drugs were administered through the proximal side hole for targeting cancer. If necessary, the gastroduodenal artery was occluded with a metal coil. No dislodgement or obstruction of the catheter was noticed in the 32 patients thus treated. The new Anthron-coated catheter with a side hole proved to be useful for prevention of catheter dislodgement and accomplishment of long-term intra-arterial infusion chemotherapy.

Aged↗
PubMed1991

Circadian rhythms of somatostatin-immunoreactivity in the suprachiasmatic nucleus of the rat.

Twenty-four hour patterns in somatostatin (SS)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) were determined by enzyme immunoassay in rats blinded by bilateral orbital enucleation or kept sighted under light-dark conditions. A remarkable circadian rhythm was found in the concentration of SS-LI in the SCN under blinded conditions. The peak time appeared at about circadian time (CT) 4 in the early subjective day and the trough at around CT 16 or 20 in the subjective night. Light-dark cycles did not alter the circadian patterns of SS-LI observed in the blinded rat SCN. These results indicate the presence of an endogenous circadian rhythm in SS-LI in the rat SCN, independent of environmental lightning cycles.

Animals↗
PubMed1991

Increased production of tumor necrosis factor-alpha by peripheral blood mononuclear cells in the patients with aplastic anemia.

The activity of tumor necrosis factor-alpha (TNF-alpha) in the supernatant of cultured peripheral blood mononuclear cells (PBMC) was measured in patients with aplastic anemia. It was significantly higher in patients with aplastic anemia than in normal controls, both when PBMC were unstimulated or when they were stimulated with PHA. Results from aplastic anemia patients were also significantly higher than patients who had received allogeneic bone marrow transplants. In aplastic anemia patients, the TNF-alpha value produced by PBMC upon stimulation and the platelet count were inversely correlated, as well those patients who had high TNF-alpha values tended to have lower hemoglobin and leukocyte values although this was not significant statistically. These results suggest that the increased production of TNF-alpha by PBMC plays a role in the severe suppression of hematopoiesis in aplastic anemia.

Anemia, Aplastic↗
PubMed1991

Radiation damage in soft X-ray microscopy of live mammalian cells.

When specimens are observed by soft X-ray microscopy, they always absorb many photons, causing radiation damage at the imaged site. The problems of radiation damage were studied in view of the principle of image formation; absorption contrast, scattering (holography), or phase contrast. In all cases, photons with a wavelength of 1-10 nm interact with the specimen mainly through the photoelectric effect followed by the transfer of energy to the imaging site either directly (absorption imaging) or indirectly (holography or phase contrast). This absorbed energy will cause structural changes to the imaging site. From a review of the literature the absorbed dose is estimated to be as high as 10(7) Gy when the expected resolution of the specimen (1-10 microns thick) is 10 nm. This dose is far in excess of the amount required for cells to be able to survive when live mammalian cells are exposed. The levels of radiation effects were extrapolated to the estimated absorbed dose from the reported values for cell survival, chromosome aberrations, and DNA strand breaks with respect to observations on mammalian chromosomes. The extrapolated results show that some damage will occur in every 10 x 10-nm (expected resolution) size unit. Although these studies focused only on the effects on mammalian chromosomes, the present results are more or less common phenomena in the observation of biological specimens. Hence, the results suggest that dynamic observations will be difficult. On the other hand, a time-scale study of the effects of radiation on structural integrity suggests that single-shot imaging with short-pulsed (probably shorter than a few milliseconds) X-rays may be appropriate for the observation of intact live biological specimens in the hydrated condition, before they have deteriorated.

Cell Survival↗
PubMed1991

Macrophages produce nitrite, nitrate and nitrosamines after addition of catalase.

Mouse macrophages produced nitrite and N-nitrosomorpholine after incubation with catalase. A macrophage cell line, J774.1 (1 x 10(6) cells/ml), was incubated with catalase (500 U/ml) and morpholine (5 mM); after 48 h incubation at 37 degrees C, macrophages produced nitrite (100 microM) and N-nitrosomorpholine (1 microM). Stimulation of J774.1 cells with catalase enhanced interleukin-1 production and tumour-killing activity against mastocytoma P815 cells. Flow cytometric analysis showed that catalase was bound to the surface of the macrophages.

Animals↗
PubMed1990

Soybean trypsin inhibitor and beta-amylase stimulate macrophages.

Mature soybean seeds were found to contain macrophage stimulation activity. The activity existed in a water-soluble fraction of soybean whey. Gel filtration, DEAE-cellulose column chromatography and high-performance liquid chromatography of the water-soluble fraction gave two active proteins. By N-terminal and total amino acid analyses, these were effectively stimulated by each of the two proteins to produce nitrite.

Amino Acids↗
PubMed1990

Establishment of a macrophagelike cell line derived from U-937, human histiocytic lymphoma, grown serum-free.

A human macrophagelike cell line which grows in serum-free medium was established from a histiocytic lymphoma cell line, U-937. U-937 cells failed to differentiate into macrophagelike cells in serum-free medium plus 12-O-tetradecanoyl phorbol 13-acetate (TPA). Fibronectin and albumin in serum were necessary for differentiation of U-937 cells into macrophagelike cells in enriched RDF medium supplemented with insulin, transferrin, ethanolamine, selenite, egg yolk lipoprotein (eRDF-ITESL medium). The established cell line exhibited several characteristic properties of macrophage such as nitroblue tetrazolium reduction, phagocytic and alpha-naphthylbutyrate-esterase activities, and tumor necrosis factor and interleukin 1 production. At present the cells have been continuously maintained in eRDF-ITESL medium through over 150 passages.

Blood↗