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Biomedical subjects

N Shibata

Publications and source records attributed to N Shibata.

At least 271 records · Page 15Linked to original sources
PubMed1991

Ultrastructure of matriceal changes in chronic phase of Masugi nephritis by quick-freezing and deep-etching method.

The three-dimensional ultrastructure of glomerular sclerosis in the chronic phase of Masugi nephritis was investigated using a quick-freezing and deep-etching method. Newly formed mesangial matrix, which was increased in the axial portions, was composed of fine fibrillar networks similar to those in the lamina densa of the basement membrane. These fibrils were 10-20 nm in diameter and directly attached to the cell membranes of mesangial cells, endothelial cells and podocytes by connecting fibrils. Moreover, thicker fibrils with diameters of 20-30 nm were present in the networks and were connected with cross-bridges. A newly formed matrix of fine fibrillar networks was also seen in the areas of mesangial interposition in the glomerular capillary wall. The border between the matrix and lamina densa was unclear. The fibrils organizing the networks of lamina densa of the glomerular loop were thickened, with some decoration. Connecting fibrils were disrupted in the areas of endothelial detachment. It is suggested that prolonged tissue injury with endothelial detachment might induce mesangial sclerosis composed of fine fibrillar networks. The increase in density of the networks seemingly interfere with the contractile function of mesangial cells, which is followed by alteration of mesangial flow.

Animals↗
PubMed1991

Candida mannan: chemistry, suppression of cell-mediated immunity, and possible mechanisms of action.

The ability of Candida albicans to establish an infection involves multiple components of this fungal pathogen, but its ability to persist in host tissue may involve primarily the immunosuppressive property of a major cell wall glycoprotein, mannan. Mannan and oligosaccharide fragments of mannan are potent inhibitors of cell-mediated immunity and appear to reproduce the immune deficit of patients with the mucocutaneous form of candidiasis. However, neither the exact structures of these inhibitory species nor their mechanisms of action have yet been clearly defined. Different investigators have proposed that mannan or mannan catabolites act upon monocytes or suppressor T lymphocytes, but research from unrelated areas has provided still other possibilities for consideration. These include interference with cytokine activities, lymphocyte-monocyte interactions, and leukocyte homing. To stimulate further research of the immunosuppressive property of C. albicans mannan, we have reviewed (i) the relationship of mannan to other antigens and virulence factors of the fungus; (ii) the chemistry of mannan, together with methods for preparation of mannan and mannan fragments; and (iii) the historical evidence for immunosuppression by Candida mannan and the mechanisms currently proposed for this property; and (iv) we have speculated upon still other mechanisms by which mannan might influence host defense functions. It is possible that understanding the immunosuppressive effects of mannan will provide clues to novel therapies for candidiasis that will enhance the efficacy of both available and future anti-Candida agents.

Animals↗
PubMed1991

A monoclonal antibody which recognizes the inner and outer segments of the photoreceptor cells in the vertebrate retina.

A monoclonal antibody (MAb-1E7), generated against bovine retinal homogenate, labeled the outer and inner segment layers of the vertebrate retina. Immuno-electron microscopic observation clearly demonstrated that antigen(s) bound by MAb-1E7 was localized in the cell membrane of the outer segment and the distal portion of the inner segment. Western blot analysis revealed that MAb-1E7 recognized 40 kD- and 27 kD-polypeptides. Mouse retina with hereditary photoreceptor degeneration (C3H/He and CBA strains) did not involve the MAb-1E7 immunoreactive structures. The present immunocytochemical observation demonstrated that MAb-1E7 was highly specific to the outer segment of the photoreceptor cells and, therefore, can be a useful marker for the cells.

Animals↗
PubMed1991

Synthesis of maltotriose by maltase purified from rabbit kidney.

To clarify the enzyme participates in maltotriose synthesis, we purified maltase from rabbit kidney using 2-amino-2-hydroxymethylpropane-1,3-diol (Tris) affinity column chromatography. The purified enzyme possessed specific activity of 33.7 mumol/mg/min and estimated molecular weight of 350,000 dalton, as judged by SDS-polyacrylamide gel electrophoresis, comparable with those reported from rat kidney. Moreover this enzyme possessed not only maltase (maltose----glucose) but also amylomaltase (maltose----maltotriose) activity, and both activities were inhibited by Tris in a dose-dependent manner with similar IC50 values. From these results, we concluded that maltotriose was synthesized by maltase in vitro and that kidney maltase may participate in sugar metabolism in vivo.

Animals↗
PubMed1991

[Pulmonary edema caused by cardiac ischemic attacks in cases with or without minimal myocardial infarction].

We report cases of angina pectoris or minimal acute myocardial infarction accompanied by pulmonary edema, which were retrospectively studied with regard to their clinical characteristics, prognosis and treatment. Sixteen patients, 5 males and 11 females with a mean age of 72.6 years, admitted to the Cardiovascular Center of Sendai between January 1986 and June 1989, were studied. Ten had previous myocardial infarction. Hypertension, chronic renal failure and diabetes mellitus were found in 10, 7 and 7 patients, respectively. Electrocardiograms during cardiac ischemic attacks showed ST elevation in 8 and ST depression in the other 8 patients. Coronary arteriography which was performed in 6 patients revealed three-vessel disease in 5, and two-vessel disease in one. Mechanical ventilation was indicative of 7, and intraaortic balloon counterpulsation in 2 patients. Coronary artery bypass graft surgery was performed for 3 patients. All patients recovered from pulmonary edema and were discharged. During the mean 15-month-follow-up period, 8 patients died. The causes of death were sudden cardiac death in 3, acute myocardial infarction in one, congestive heart failure in one, post-surgical death in one, and non-cardiac death in 2.

Aged↗
PubMed1990

Structure of the D-mannan of Candida stellatoidea IFO 1397 strain. Comparison with that of the phospho-D-mannan of Candida albicans NIH B-792 strain.

The structure of the D-mannan of Candida stellatoidea IFO 1397 strain, which has properties identical to those of the phospho-D-mannan of C. albicans serotype B strain, does not contain phosphate groups, and its 1H- and 13C-n.m.r. spectra are quite similar to those of the phospho-D-mannan of C. albicans NIH B-792 strain. However, the 1H-n.m.r. and 1H-13C-correlation n.m.r. spectra of the products obtained by digestion with alpha-D-mannosidase of C. stellatoidea D-mannan considerably differed from those of the corresponding digestion products of the C. albicans phospho-D-mannan. Additionally, the enzyme-linked immunosorbent assay, by means of a monoclonal antibody corresponding to (1----2)-linked beta-D-oligomannosyl residues, of the phospho-D-mannan of the same C. albicans strain indicated that the C. stellatoidea D-mannan does not contain any (1----2)-linked beta-D-oligomannosyl residues. The absence of these residues may be used as one of the criteria of chemotaxonomical identification of C. stellatoidea spp.

Candida↗
PubMed1990

Structural study of cell wall phosphomannan of Candida albicans NIH B-792 (serotype B) strain, with special reference to 1H and 13C NMR analyses of acid-labile oligomannosyl residues.

Chemical structures of manno-oligosaccharides, from biose to heptaose, released from the phosphomannan of Candida albicans NIH B-792 strain (serotype B) by mild acid hydrolysis were investigated. The results of 1H NMR, 13C NMR, and fast atom bombardment mass spectrometry analyses confirmed that these manno-oligosaccharides belong to a homologous beta-1,2-linked series. Although chemical shifts of 1H NMR patterns of these oligosaccharides were considerably too complicated to be assigned, their 13C NMR patterns were sufficiently simple to be interpreted, exhibiting a regular increase of downfield shift of ppm values of the C-1 atom from each mannopyranose residue in proportion to their molecular weights. In order to determine the whole chemical structure of the parent phosphomannan, the acid-stable domain was subjected to acetolysis and then enzymolysis with the Arthrobacter GJM-1 alpha-mannosidase and the resultant manno-oligosaccharides were investigated for their chemical structures by 1H NMR spectroscopy. The results of a precipitin-inhibition test using the beta-1,2-linked manno-oligosaccharides, from biose to hexaose, in comparison with the corresponding isomers containing alpha-1,2 linkage with small amounts of alpha-1,3 linkage, indicated that the haptens possessing the former linkage exhibited much higher inhibitory effects than the corresponding isomers containing the latter linkages did. Based on the present findings, a chemical structure of the phosphomannan of this C. albicans strain was proposed.

Arthrobacter↗
PubMed1990

Adverse effects of obesity on lipid and lipoprotein levels in the patients with non-insulin dependent diabetes in the young.

We studied the association of obesity with serum lipid and lipoprotein concentrations in 117 patients (62 males and 55 females) with NIDDY and in 40 nondiabetic control subjects (21 males and 19 females). Obesity at a young age was related to increased lipid and lipoprotein levels both in the patients with NIDDM and the control group. Moreover, low HDL-c levels were aggravated by diabetic status only in males. The BMI and fasting insulin level had a statistically significant correlation with the TG and HDL-c level and various atherogenic factors. Therefore, it is suggested that the lipid abnormalities seen in obesity may be associated with hyperinsulinemia. We conclude that obesity in adolescence leads to aberrations of the serum lipid and lipoprotein levels, particularly in obese males with NIDDY.

Adolescent↗
PubMed1990

Enhanced expression of the tumour necrosis factor/cachectin gene in peripheral blood mononuclear cells from patients with systemic vasculitis.

The expression of tumour necrosis factor-alpha (TNF-alpha) gene in peripheral blood mononuclear cells from patients with systemic vasculitis, periarteritis nodosa and Wegener's granulomatosis, has been studied by RNA dot blot and Northern blot assays. We further examined the transcriptional level of TNF-alpha gene in peripheral blood mononuclear cells from these patients by performing nuclear run on transcription assay. We demonstrate enhanced TNF-alpha gene expression in mononuclear cells from these patients compared with healthy subjects and patients with bronchial asthma. These findings suggest that the enhanced transcription of TNF-alpha gene in peripheral blood mononuclear cells from patients with systemic vasculitis may be involved in the pathophysiology/pathogenesis of these diseases by cytokine dysregulation.

Adult↗
PubMed1990

Elevated transcription of heat shock protein gene in scleroderma fibroblasts.

Scleroderma is a systemic disorder characterized by fibrosis, which affects skin, lung, kidney and other organs. Heat shock protein (hsp) (70 kD) has been implicated as an essential element of cell function in cell growth and differentiation. To study the molecular basis of intracellular events in scleroderma fibroblasts, we compared the expression of hsp 70 gene in scleroderma and normal control fibroblasts by nuclear run on transcription assay and Northern blot assay. We show that scleroderma fibroblasts express more than eight times higher level of hsp 70 transcription in normal control fibroblasts at quiescent conditions in the absence of serum. After stimulation with serum, the transcription level of the hsp 70 gene is similar in scleroderma and normal control fibroblasts. Therefore, our results indicate an alteration/activation of intracellular events in scleroderma fibroblasts.

Adult↗
PubMed1990

A model to account for the blood-to-plasma distribution of cyclosporin A in human blood.

A mathematical model to account for the blood-to-plasma distribution of cyclosporin A (CyA) in human blood was derived, and alterations in the blood-to-plasma distribution of CyA under several influencing conditions were examined using this model. The model was derived on the assumption that there are two CyA binding sites in human blood, which exist in plasma and cellular fractions. In the plasma fraction, the CyA binding sites are mainly lipoproteins (LPs), in which CyA exhibits nonsaturable, low affinity binding with LPs independent of drug concentration. In the cellular fraction, the binding site of CyA is the CyA binding protein (CBP), in which CyA shows a specific binding in a temperature dependent, saturable process. The results obtained from simulative studies agreed with previous reports on the blood-to-plasma distribution of CyA, indicating the usefulness of this approach. And also, this model may be used to predetermine individual variations in the blood-to-plasma distribution of the drug in renal transplant patients.

Blood↗
PubMed1990

[Cyclosporin levels in semen of renal transplant patients].

Cyclosporin (CsA) has powerful immunosuppressive properties, and its recent application to organ transplantation has resulted in markedly improved graft survival. However, CsA has certain adverse side effects, the most notable being nephrotoxicity and hepatotoxicity. Among other untoward effects, little is known about the effects of CsA on the reproductive organs. Since good graft survival is now expected with CsA, the long term effect of the drug on the gonads should be monitored carefully, particularly for young recipients. Prior to investigation of the effect of CsA on the testis, the level of CsA in semen of the adult renal transplant patients were measured. Twelve samples of semen from eight recipients, mean age 35 (SD 9), were collected by masturbation in the morning just before taking CsA after more than 5 day abstinence, and it was frozen at -80 degrees C. They had been taking immunosuppressants that were a combination of either CsA and prednisolone, or CsA, azathioprine and prednisolone for 5 to 63 months. The dose of CsA was 3.7 mg/kg to 5.0 mg/kg. The range of the level of serum creatinine was 1.1 mg/dl to 2.9 mg/dl. CsA in whole blood was measured by high performance liquid chromatography (HPLC), and CsA in semen was also measured by HPLC after extracting CsA with diethylether. The level of CsA in semen was 27 ng/ml to 165 ng/ml and that in whole blood was 51 ng/ml to 133 ng/ml. The relation between both levels was linear (r = 0.68, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Myoclonus of the abdominal muscles originated in spinal vascular malformation].

We studied segmental spinal myoclonus of abdominal muscles observed in a 62-year-old man. The myoclonus consisted of continuous rhythmic contractions of the bilateral abdominal muscles at T8-T10 segments at a rate of 3 to 4 c/s. It was observed with the patient was in supine position and almost exclusively during the expiratory phase, and it disappeared during sleep. The myoclonus decreased in amplitude or disappeared during physical exercise, and intensified for a few minutes after physical exercise including breath-holding by Valsalva's maneuver. Myelography showed spinal vascular malformation at the level of T9-T11 vertebrae. Electromyography showed neurogenic change of the paravertebral muscles at T5-T11 segments on the right side and T7-T9 segments on the left side. Hypoalgesic zone contained those segments. The myoclonus disappeared for a short period after lumbar puncture and improved by administration of clonazepam.

Abdominal Muscles↗
PubMed1990

[Parkinsonism associated with cerebrotendinous xanthomatosis].

Two sibling cases of cerebrotendinous xanthomatosis with parkinsonism were reported. One was a woman of 39 years old, and another was her sister of 36 years old. In both cases, febrile convulsion appeared on 1.5 year old, and mental deterioration, ataxic -spastic gait, cataract and swelling of Achilles tendons developed in order since entrance into elementary school. Five years ago, while they were in hospital at the first time, they were diagnosed as cerebrotendinous xanthomatosis by mental disturbance, cerebellar ataxia, pyramidal tract sign, histologically xanthomatous granuloma of Achilles tendons and hypercholestanolemia and family history of autosomal recessive trait. After the second admission, parkinsonism was noticed in addition to those findings above. Parkinsonism consisted of the following: Resting tremor of parkinsonian type, mild muscle rigidity of forearm and intrinsic-plus hand were observed in the elder sister, and generalized severe rigidity and bradykinesia in the younger sister. In both cases, brain CT showed the pontocerebellar atrophy, and the bilateral low density area in corona radiata, posterior portion of internal capsule, cerebral peduncle, tegmentum of midbrain and deep matter of cerebellum. Brain MRI also showed abnormal intensity in the same regions as on the brain CT. Administration of anti-parkinsonian drugs was challenged for the parkinsonism. Oral L-dopa test (500 mg) moderately improved parkinsonism in both cases. Therapy of diphenylpyraline hydrochloride (10 mg/day) entirely inhibited parkinsonian tremor and mild rigidity in the elder sister but was less effective for severe rigidity in the younger sister than administration of L-dopa.(ABSTRACT TRUNCATED AT 250 WORDS)

Achilles Tendon↗
PubMed1989

Tropomyosin-caldesmon/actomyosin systems in platelets and arterial smooth muscle: results from exchange experiments.

Tropomyosin and caldesomon reciprocally control the actomyosin system in smooth muscle and some non-muscle cells. To compare this mechanism between arterial smooth muscle and platelets, we carried out extensive exchange experiments. Actin, myosin, tropomyosin from arterial smooth muscle cells and platelets were recombined and the effects of two species of caldesmon ('caldesmon77' and 'caldesmon140') on the ATPase activities of both systems were examined and analyzed by the method of analysis of variance. (a) The actomyosin system itself is different between artery and platelets, the difference being determined by myosin (P less than 0.05) and not by actin. (b) Platelet tropomyosin differentiates platelet actin from arterial actin (P less than 0.01), while arterial tropomyosin does not. Neither does tropomyosin differentiate myosin. (c) The effect of caldesmon77 differentiates the origins of myosin (P less than 0.01), actin (P less than 0.05) and tropomyosin (P less than 0.05). The effect of caldesmon140 differentiates the origin of myosin (P less than 0.05) and the actin-myosin 'interaction' (combination) (P less than 0.01), but not the origin of tropomyosin (P greater than 0.1). (1) It is concluded that actomyosin/tropomyosin-caldesmon system is distinguishable between platelets and artery. (2) It is suggested that caldesmon is an actomyosin inhibitor which may interact with myosin, in addition to actin and tropomyosin.

Actins↗
PubMed1989

Structural study of phosphomannan of yeast-form cells of Candida albicans J-1012 strain with special reference to application of mild acetolysis.

Structural analysis of the phosphomannan isolated from yeast-form cells of a pathogenic yeast, Candida albicans J-1012 strain, was conducted. Treatment of this phosphomannan (Fr. J) with 10 mM HCl at 100 degrees C for 60 min gave a mixture of beta-1,2-linked manno-oligosaccharides, from tetraose to biose plus mannose, and an acid-stable mannan moiety (Fr. J-a), which was then acetolyzed by means of an acetolysis medium, 100:100:1 (v/v) mixture of (CH3CO)2O, CH3COOH, and H2SO4, at 40 degrees C for 36 h in order to avoid cleavage of the beta-1,2 linkage. The resultant manno-oligosaccharide mixture was fractionated on a column of Bio-Gel P-2 to yield insufficiently resolved manno-oligosaccharide fractions higher than pentaose and lower manno-oligosaccharides ranging from tetraose to biose plus mannose. The higher manno-oligosaccharide fraction was then digested with the Arthrobacter GJM-1 alpha-mannosidase in order to cleave the enzyme-susceptible alpha-1,2 and alpha-1,3 linkages, leaving manno-oligosaccharides containing the beta-1,2 linkage at their nonreducing terminal sites, Manp beta 1----2Manp alpha 1----2Manp alpha 1----2Manp alpha 1----2Man, Manp beta 1----2Manp beta 1----2Manp alpha 1----2Manp alpha 1---- 2Manp alpha 1----2Man, and Manp beta 1----2Manp beta 1----2Manp beta 1----2Manp alpha 1---- 2Manp alpha 1----2Manp alpha 1----2Man. However, the result of acetolysis of Fr. J-a by means of a 10:10:1 (v/v) mixture of (CH3CO)2O, CH3COOH, and H2SO4 at 40 degrees C for 13 h was significantly different from that obtained by the mild acetolysis method; i.e., the amount of mannose was apparently larger than that formed by the mild acetolysis method. In summary, a chemical structure for Fr. J as a highly branched mannan containing 14 different branching moieties was proposed.

Acetic Anhydrides↗