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Biomedical subjects

S Shimizu

Publications and source records attributed to S Shimizu.

At least 721 records · Page 40Linked to original sources
PubMed1990

Inhibition of ubiquinone synthesis in isolated rat heart under an ischemic condition.

1. The biosynthesis of ubiquinone (UQ) in isolated rat heart under ischemic and hypoxic conditions was investigated. 2. Under ischemic perfusion, a greater amount of biosynthetic intermediates, 3-nonaprenyl and 3-decaprenyl-4-hydroxybenzoate (PPHBs) was accumulated and a smaller amount of UQ-9 and -10 was synthesized when compared with normal conditions. 3. The accumulation of PPHBs was observed without forming UQs during anaerobic perfusion. 4. Hydroxylation which is the following reaction of PPHBs for the biosynthesis of UQ in rat heart, was proceeded by the monooxygenase(s) depending upon the oxygen concentrations.

Animals↗
PubMed1990

The range of albumin concentrations in the single-void first morning urine of 1090 healthy young children.

To predict microalbuminuria easily in the diabetic outpatient clinic, we determined the range of albumin concentrations in the single-void first morning urine in 1090 healthy subjects of age 6-11 by the modified turbidimetry immunoassay (TIA) method, which uses 96-well microplates and a microplate reader to perform the assay quickly and conveniently. As the correlation coefficient of albumin concentration by the TIA uncorrected for creatinine versus corrected for creatinine was r = 0.79 (P less than 0.005), the values uncorrected for creatinine were used. When the distribution of values from 1090 healthy young children was simulated by using the chi-square test (k = 1), the 95% confidence interval was 0-18 micrograms/ml.

Albuminuria↗
PubMed1990

Use of endoscopic ultrasonography for the diagnosis of colorectal tumors.

Ultrasonographic evaluation of colorectal diseases has been realized by the development of echocolonoscopes. Endoscopic ultrasonography was performed in 90 cases of colorectal tumor, and the diagnostic yields were assessed; the cases included 72 with cancer, 13 with polyp, and 5 with submucosal tumor. With respect to cancer extent, EUS correctly estimated the depth of cancer invasion in 84.9% of 53 cases in which the lesion was appropriately visualized. Paraintestinal lymph node metastasis was detected in 38.1%. EUS was not so successful in the evaluation of polyps, since the histological types could not be differentiated, nor could the focus of cancer in adenoma be demonstrated. EUS was effective in the differential diagnosis of submucosal tumors, since the ultrasonographic features varied by histological types.

Carcinoid Tumor↗
PubMed1990

Deduced primary structure of rat hepatocyte growth factor and expression of the mRNA in rat tissues.

The primary structure of rat hepatocyte growth factor (HGF) was elucidated by determining the base sequence of the complementary DNA (cDNA) of HGF. The cDNA for rat HGF was isolated by screening a liver cDNA library with oligonucleotides based on the partial N-terminal amino acid sequence of the beta subunit of purified rat HGF. HGF is encoded in an mRNA of about 6 kilobases. Both alpha and beta subunits of HGF are specified in a single open reading frame for a 728-amino acid protein with a calculated molecular weight of 82,904. The N-terminal part of HGF has a signal sequence and a prosequence with 30 and 25 amino acid residues, respectively. The mature heterodimer structure is derived proteolytically from this single pre-pro precursor polypeptide. The calculated molecular weights of the alpha and beta subunits are 50,664 and 25,883, respectively, and each subunit has two potential N-linked glycosylation sites. The amino acid sequence of HGF is 38% identical with that of plasminogen. The alpha subunit of HGF contains four "kringle" structures, and the beta subunit has 37% amino acid identity with the serine protease domain of plasmin. Northern blot analysis revealed that HGF mRNA was expressed in rat various tissues, including the liver, kidney, lung, and brain.

Amino Acid Sequence↗
PubMed1990

Interferon-alpha and interferon-beta induce Ia expression in limited protein synthesis condition.

We investigated the regulatory effect of interferons (IFNs) on macrophage (m phi) Ia antigen expression. Unlike type II IFN (IFN-gamma), type I IFNs (IFN-alpha and IFN-beta) were incapable of inducing the accumulation of Ia mRNA. However, when cultured with type I IFN plus cycloheximide (CHX), M phi accumulated significant amounts of Ia-specific mRNA, which was translated into Ia molecules expressed on the cell surface after the removal of CHX. Significant enhancement of Ia mRNA accumulation and the Ia expression were observed also in M phi stimulated with IFN-gamma plus CHX. Type I IFNs suppressed IFN-gamma-dependent Ia expression through the inhibition of Ia mRNA accumulation, but such suppression was not directed to the post-transcriptional step in M phi that had accumulated Ia mRNA in response to stimulation by type I or type II IFN plus CHX. These results seem to indicate that type I IFNs can induce Ia mRNA accumulation but that they also induce some inhibitory protein, the synthesis of which precedes it and is dominant, so that the Ia expression is masked.

Animals↗
PubMed1990

Immunoreactive circulating alpha-interferon is low in Sjögren's syndrome.

Circulating alpha-interferon in plasma of 26 patients with Sjögren's syndrome was 0.069 +/- 0.034 ng/ml, a significant decrease compared with 0.119 +/- 0.051 ng/ml for age- and sex-matched healthy subjects (P less than 0.01) and compared with values previously found for healthy donors at ages 1-89 years. The results indicate the inability of Sjögren's syndrome patients to maintain circulating alpha-interferon.

Adult↗
PubMed1990

Light and electron microscopic study of vacuolated cells in immunoblastic lymphadenopathy-like T-cell lymphoma.

Three cases of immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma were analyzed immunologically, and the ultrastructure of mononuclear cells in the lymph nodes and peripheral blood was examined. In the peripheral blood, light microscopic examination revealed vacuolated lymphocytes. These vacuolated lymphocytes formed rosettes with sheep erythrocytes, and they were CD3- and CD4-positive using the avidin-biotin method in cases 1 and 2. Electron microscopic examination revealed two kinds of abnormal lymphocytes. One kind was of B-cell nature with rich lamellated rough-surfaced endoplasmic reticulum and mitochondria. The other kind had a large cytoplasm, in which Golgi apparatus, some endoplasmic reticulum, some mitochondria and a few vacuoles were seen. Some of these vacuoles had remnants of mitochondrial cristae or were enlarged endoplasmic reticulum. The vacuolated T lymphocytes and activated lymphocytes of B-cell nature disappeared with chemotherapy but reappeared with relapse of the disease. These observations suggest that vacuolated cells are related to pale cells in lymph node sections. In other words when these vacuolated cells are found in the peripheral blood of patients with lymphoid malignancies, IBL-like T-cell lymphoma can be suspected.

Aged↗
PubMed1990

Biclonality of composite B- and T-cell lymphomas. A case report.

Most composite lymphomas which are composed morphologically of two different tumor cell types are considered to represent different morphological expressions of a single clone. However, in recent years, composite B- and T-cell lymphomas and biclonality of B-cell lymphoma have been reported. We experienced a case of composite lymphoma which initially developed as cutaneous lymphoma composed of lymphoplasmacytes associated with large clear cells. It was confirmed that the tumor cells of these two systems were biclonal on the basis of surface markers and DNA rearrangements, i.e. B cells of the IgG kappa type, showing IgH and kappa chain DNA rearrangement, and T-cells with CD4 surface marker, showing rearrangement of the T-cell receptor beta chain gene. This case showed a predominant B-cell pattern at the initial stage, and terminated in T-cell lymphoma, as revealed at autopsy. Therefore we considered this case to be a unique composite lymphoma showing biclonality of both B- and T-cell systems, providing a number of suggestions for future study of malignant lymphoma.

Aged↗
PubMed1990

Inhibition of noradrenaline release from cerebrocortical synaptosomes and stimulation of synaptosomal Na+,K(+)-ATPase activity by morphine in rats.

The effects of morphine on noradrenaline (NA) release from rat cerebrocortical synaptosomes and on the synaptosomal Na+,K(+)-ATPase activity were determined. Morphine (10(-3)-10(-5) M) caused a dose-related inhibition of enhanced prelabelled [3H]NA release evoked by a high concentration of K+ from synaptosomes and this inhibitory action of morphine was antagonized by the specific antagonist naloxone (10(-4), 10(-5) M). Morphine dose-dependently stimulated the synaptosomal Na+,K(+)-ATPase activity but not Ca2(+)-ATPase activity in the incubation medium containing 2.2 x 10(-6)-4.7 x 10(-7) M free Ca2+, and this stimulatory effect was antagonized by naloxone. These results suggest that morphine may have some role in the suppression of membrane depolarization and/or the release of NA through its stimulatory action on the Na+,K(+)-ATPase activity in rat cerebral cortex.

Animals↗
PubMed1990

Purification and properties of an endo-1,4-beta-glucanase translated from a Clostridium josui gene in Escherichia coli.

An endoglucanase encoded by a gene of Clostridium josui was expressed in Escherichia coli and purified. The homogeneous enzyme, with a molecular weight of 39,000, revealed maximum endoglucanase activity at pH 7.2 to 7.5 and a temperature of 65 to 70 degrees C. The enzyme was stable at a temperature lower than 45 degrees C (the growth temperature of the bacterium) in the range of pH 4.5 to 9.0. The amino acid sequence of the enzyme at the N terminus was Val-Glu-Glu-Asp-Ser-Ser-His-Leu-Ile-Thr-Asn-Gln-Ala-Lys-Lys----. The enzyme hydrolyzed cellotetraose to cellobiose and then transferred cellobiose to the residual cellotetraose. The resulting cellohexaose was cleaved to cellotriose.

Amino Acid Sequence↗
PubMed1990

Interaction of asterriquinone with deoxyribonucleic acid in vitro.

The interaction of asterriquinone (ARQ), a novel antitumor agent isolated from Aspergillus fungi, with deoxyribonucleic acid (DNA), has been studied. The binding of ARQ in vitro with DNA (calf thymus) was ascertained by its behavior in gel filtration using a Sephadex G-25 column at pH 5.4. Some ARQ analogs having no, or less, antitumor activity did not exhibit any evidence of interaction with DNA under the same condition. From the results obtained in this work, the pKa value of ARQs seemed to be critical between 6 and 7 for their binding to DNA and for exhibition of antitumor activity. Also, ARQ showed serious membrane deformations and an inhibitory effect on the membranous adenosine triphosphatase of Ehrlich carcinoma cells.

Animals↗
PubMed1990

[Effect of dilazep dihydrochloride on ischemia and reperfusion-induced cerebral injury in spontaneously hypertensive rats].

We examined the effect of dilazep dihydrochloride (dilazep) on ischemia and reperfusion-induced cerebral injury in spontaneously hypertensive rats (SHRs). Ataxia and loss of the righting reflex were noted in some SHR after 4 hr occlusion of the bilateral common carotid arteries; and 11 of 15 animals died within 72 hr after reperfusion. One hour after reperfusion, the cerebral water content increased significantly. The chemiluminescence value in the brain homogenate increased slightly during occlusion; and following reperfusion, there was a transient but marked further increase, indicating the acceleration of lipid peroxidation that resulted from free radical reactions. The i.v. infusion of dilazep (0.3-3 mg/kg/hr for 4 hr) during occlusion dose-dependently reduced the appearances of neurological symptoms and mortality during occlusion and after reperfusion. The increase in cerebral water content and chemiluminescence value were clearly prevented by dilazep (3 mg/kg/hr). It is concluded that dilazep possesses the ability to prevent the appearances of neurological symptoms and brain edema induced by ischemia and reperfusion. The suppression of lipid peroxidation may be involved in the mechanism of the preventive effect of dilazep on cerebral injury.

Animals↗
PubMed1990

[Clinical investigation of stercoral ulcer].

Analysis of 14 cases of stercoral ulcer showed that they tended to occur in patients over 70 years of age and associated diseases included heart failure under hemodialysis, cerebral hemorrhage, and postoperative states requiring bet rest for long duration. Constipation is always preceded the occurrence of the disease, and the initial symptoms was generally massive hematochezia of sudden onset. Massive blood transfusion was often required, however, heater probe hemostasis was effective. The most common site of involvement was the rectum, and the shape of ulcer was irregular or round. Measurement of the mucosal blood flow in the rectum revealed that blood perfusion was markedly reduced immediately after the occurrence, and that it recovered with healing of ulcer. Ischemia was considered to participate in the pathogenesis of the disease.

Aged↗