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Biomedical subjects

M Otsuka

Publications and source records attributed to M Otsuka.

At least 397 records · Page 22Linked to original sources
PubMed1988

Characterization of abnormal nuclei in renal proximal tubules after irradiation.

The distribution and kinetics of proximal tubular cells with abnormally large nuclei, which were observed in irradiated mouse kidneys before any other obvious histological effects, were investigated. Six months after the administration of 13 or 15 Gy, little histopathological change was noted, in the kidneys of C3H mice; however, proliferation of proximal tubular cells was stimulated, and some of these cells had abnormally large nuclei. The relative DNA content of these large nuclei was measured with a quantitative image analysis system. Most of the large nuclear cells had more than diploid DNA content. The labeling index of the large nuclei was higher than that of unselected proximal tubular nuclei. These cells might be hyperploid cells that are dying after having gone through an abortive mitotic division. Examination and quantitation of these abnormal nuclei should be useful in elucidating the steps involved in cell loss in the proximal tubules after irradiation and as an assay for radiation damage to the kidney.

Animals↗
PubMed1987

Degradation of human secretory immunoglobulin A by protease isolated from the anaerobic periodontopathogenic bacterium, Bacteroides gingivalis.

This bacterium is implicated in periodontal diseases of human adult type. Secretory immunoglobulin A (IgA) purified from human colostrum (HC-IgA) was incubated with Bacteroides gingivalis cells or protease isolated from the culture supernatant of B. gingivalis; the digestion of IgA was determined by immunoelectrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. B. gingivalis cells almost completely degraded HC-IgA; protease isolated from the culture supernatant cleaved both HC-IgA and secretory IgA in human parotid saliva. Thus by degradation of IgA, the protease may mediate in part the periodontopathogenic role of B. gingivalis by decreasing the oral defence mechanism.

Bacteroides↗
PubMed1987

[Basic and clinical evaluation of a new assay procedure "SCC RIABEAD" for estimation of squamous cell carcinoma related antigen].

We examined the efficacy of a new commercial assay procedure (SCC RIABEAD) for estimation of squamous cell carcinoma related antigen (SCC). Intraassay and interassay variance were 4.0-14.6% and 4.6-17.0% respectively. Recovery and dilution tests gave satisfactory results. The normal range was under the level of 1.63 ng/ml. The patients with uterine cervical cancer or squamous cell carcinoma of the lung showed high positive rates. The values of SCC measured by SCC RIABEAD were well-correlated to those by SCC RIAKIT. However, SCC RIABEAD showed lower values in low SCC level and higher values in high SCC level than SCC RIAKIT.

Adult↗
PubMed1987

Analysis of kinetic rate constants in [18F]fluorodeoxyglucose model using a least square fitting package SALS (statistical analysis with least squares).

The analysis of kinetic rate constants in the compartment model for [18F]fluorodeoxyglucose (FDG) was undertaken. Four kinetic rate constants were determined with a least square fitting package SALS (Statistical Analysis with Least Squares), using the measured data of 18F activity as a function of time. SALS calculations were found to be easy and quick with high precision. The rate constants and the curves fitted by the k3 and the k4 models were compared in situations with various degree of cerebral glucose metabolism during positron emission tomography (PET) studies. The k4 model in the determination of cerebral metabolic rate for glucose (CMRglu) was much superior than the k3 model in any given situation as it always underestimates the metabolic rate. However, the k3 model produces less variation when the cerebral radioactivity curve shows steady rising pattern.

Brain↗
PubMed1987

Effect of a substance P antagonist on capsaicin-induced nociceptive reflex in the isolated spinal cord-tail preparation of the rat.

An isolated spinal cord-tail preparation of the newborn rat was developed and used for studying the effects of various drugs. The cord and the tail were separately perfused with oxygenated artificial cerebrospinal fluid. Application of capsaicin in a small amount to the tail induced a depolarizing response of the lumbar ventral root (L3-L5) lasting for about 30 sec. The stimulating action of capsaicin was potentiated by previous perfusion of the tail with a medium containing prostaglandin E1 or E2. The capsaicin-induced nociceptive reflex was depressed by application to the spinal cord of morphine, Met-enkephalin, dynorphin (1-13), somatostatin, adenosine, GABA and a substance P (SP) antagonist [D-Arg1, D-Pro2, D-Trp7,9, Leu11]SP, and potentiated by bicuculline. The present preparation will be useful for the future studies on pain and analgesic drugs.

Animals↗
PubMed1987

[Malignant lymphoma from left renal capsule: report of case].

A 59-year-old woman was admitted to our clinic with the complaint of left flank pain. Excretory urogram showed left hydronephrosis. Computed tomographic (CT) scan and renal angiography showed a left renal capsular tumor. Histological specimen obtained by a sure cut needle suggested malignant lymphoma. She was treated with a combined treatment of 8 MHz radiofrequency hyperthermia in a total of 10 sessions and 5,440 rads irradiation for 5 weeks. After the treatment, CT scan showed 92% tumor regression. After that, a recurrent tumor in left shoulder muscle became manifest. She received combination chemotherapy with 3 courses of ABEP regimen (aclacinomycin, cytosine arabinoside, etoposide, prednisolone) and 7 courses of ACOPE regimen (adriamycin, cyclophosphamide, vincristine, prednisolone, etoposide) and complete remission was obtained.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Inhibitory effects of galanin on the isolated spinal cord of the newborn rat.

The effects of galanin, a 29-amino-acid peptide, on spinal reflexes were studied. In the isolated hemisected spinal cord of the newborn rat, galanin (0.1-5 microM) depressed the monosynaptic reflex that was induced by dorsal root stimulation and recorded from the corresponding ventral root. In the isolated spinal cord-tail preparation of the newborn rat, galanin (0.3-0.6 microM) depressed the nociceptive reflex that was induced by application of capsaicin to the tail and recorded from a lumbar ventral root. In both preparations the inhibitory effects of galanin were reversible and the full recovery of the reflexes was observed within 3-20 min after removal of the peptide. The mechanisms of action of galanin on the spinal reflexes and the physiological role of the peptide in the spinal cord are discussed.

Animals↗
PubMed1986

E-type prostaglandins depolarize primary afferent neurons of the neonatal rat.

The mechanism of action of prostaglandins (PGs) to sensitize sensory terminals to noxious stimuli was studied in the isolated spinal cord-tail preparation of the newborn rat. Application of a small amount of capsaicin to the tail induced a nociceptive reflex that was recorded extracellularly from the lumbar ventral root. Pretreatment of the tail with PGE1 or E2 (0.8-4 microM) markedly potentiated the capsaicin-induced nociceptive reflex. In the isolated spinal cord preparation of the newborn rat, application of PGE1 or E2 (10 nM-1 microM) induced a depolarization of the dorsal root. Based on these results we propose a hypothesis that PGs regulate the resting potential of the peripheral terminals of nociceptive primary afferent fibers and that the depolarization is associated with lowering of threshold for various noxious stimuli.

Animals↗
PubMed1986

Descending inhibition of slow spinal reflex in an in vitro preparation of the newborn rat and its possible involvement in pain control.

An isolated brainstem-spinal cord preparation of the newborn rat is described in which brainstem stimulation inhibits a spinal reflex of slow time course possibly associated with nociception. The inhibition-producing area is localized in the rostral medulla and caudal pons. Perfusion of the preparation with phentolamine or strychnine antagonizes the inhibition, suggesting the involvement of alpha-adrenergic and glycine-mediated inhibitory mechanisms. Results are discussed in relation to descending inhibition of nociception.

Animals↗
PubMed1986

Effect of seed crystals on solid-state transformation of polymorphs of chloramphenicol palmitate during grinding.

The polymorphic transformations of chloramphenicol palmitate, (2R, 3R)-2-(2,2-dichloroacetamido)-3-hydroxy-3-(4-nitrophenyl) propyl palmitate (1), during grinding in an agate centrifugal ball mill at 200 rpm, and the effect of seed crystals on the transformation were studied by means of X-ray diffraction analysis, differential scanning calorimetry, and scanning electron microscopy. The transformation was analyzed using the kinetic method based on nine kinetic model equations. Form B of 1 was transformed to form A (the therapeutically least active form) during grinding for more than 150 min, but in the presence of 1% of form A as seed crystals, form B was transformed to form A during grinding for 40 min. The transformations of form B during grinding in the absence and in the presence of seed crystals were fitted to the two-dimensional nuclear growth equation (Avrami equation). Form C was transformed to form B during grinding for 16 min (and then to form A when grinding was continued for a total of 160 min). The transformation of form C to form B during grinding was accelerated by the presence of 1% of form B, while the subsequent transformation to form A was unaffected, as expected. On the other hand, in the presence of 1% of form A, both the transformation of form C to form B and the subsequent transformation to form A were completed within a grinding time of only 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Calorimetry, Differential Scanning↗
PubMed1986

Hypotensive response of spontaneously hypertensive rats to centrally administered diltiazem and its metabolites: in relevance to the hypotensive action by oral administration.

In order to study whether a part of the antihypertensive action of orally administered diltiazem is mediated by the central nervous system and whether metabolites of diltiazem contribute to the actions of diltiazem, we compared the effects of diltiazem and its main metabolites on blood pressure by intravenous administration with those by intracerebroventricular administration to spontaneously hypertensive rats (SHR). Contents of diltiazem and its metabolites in the brain of SHR after oral administration were also studied. Hypotensive action of intravenously administered diltiazem was stronger than that of its main metabolites in terms of potency and durability. Diltiazem (30 micrograms or more) and its main metabolites (100 micrograms) showed weak hypotensive action by intracerebroventricular administration. Oral administration of diltiazem (30 mg/kg) decreased mean blood pressure by about 40 mmHg 30 min after the administration. At this time, contents of unchanged form and metabolites of diltiazem in the brain were 0.78 +/- 0.10 and 7.58 +/- 0.89 micrograms/whole brain, respectively. It was suggested that hypotensive action of diltiazem was mainly attributable to the unchanged form and that the contribution of central action to the acute hypotensive action of diltiazem was unlikely, although centrally administered diltiazem can cause systemic hypotension.

Administration, Oral↗