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Biomedical subjects

M Kawaguchi

Publications and source records attributed to M Kawaguchi.

At least 235 records · Page 13Linked to original sources
PubMed1993

Effect of ascorbic acid on pituitary prolactin secretion in the non-ascorbate synthesizing Osteogenic Disorder Shionogi (ODS) rat.

We examined the secretion of prolactin (PRL) in the hereditary scurvy-prone Osteogenic Disorder Shionogi (ODS) rat to investigate the role of ascorbic acid (AsA) in pituitary lactotroph and hypothalamic function. Plasma PRL concentrations of conscious AsA-deficient or control ODS rats were measured before and after the administration of metoclopramide (MCP), 5-hydroxy-L-tryptophan (5-HTP) or saline. The basal plasma PRL levels did not differ between the two groups. However, the AsA-deficient rats exhibited significantly larger changes in plasma prolactin concentration in response to MCP or 5-HTP than the control ODS rats. Thus, AsA deficiency enhanced the stimulated, but not the basal, secretion of PRL in ODS rats. Our findings suggest that AsA may have an inhibitory effect on PRL secretion.

5-Hydroxytryptophan↗
PubMed1993

Effect of thiopentone on motor evoked potentials induced by transcranial magnetic stimulation in humans.

We have studied the effect of repeated doses of thiopentone on motor evoked potentials (MEP) after transcranial magnetic stimulation in 13 patients. Thiopentone was administered i.v. in an initial dose of 2 mg kg-1, followed by repeated doses (1 mg kg-1 every 3 min) until the appearance of burst suppression on the EEG. The total dose administered was mean 10.7 (SD 2.6) mg kg-1. The magnetic coil was placed over the MEP scalp stimulation region and evoked electromyographic responses were recorded from the contralateral abductor pollicis brevis. After an initial dose of thiopentone, reproducible MEP responses were recorded in all patients, but amplitudes were reduced to 42.8% of baseline values. Further administration of repeated doses of thiopentone produced a dose-dependent decrease in success rate of MEP recordings and a significant reduction in MEP amplitude (P < 0.01). Latency did not change significantly, although there was a tendency to increase. During burst suppression on the EEG, MEP was not recorded successfully in all patients. We conclude that MEP recording during the administration of thiopentone is feasible only at a minimum dose, with a marked reduction in MEP amplitude.

Adult↗
PubMed1993

Intra-operative monitoring of cerebral haemodynamics in a patient with Takayasu's arteritis.

Transcranial Doppler and continuous measurements of jugular venous oxygen saturation were used to monitor intra-operative cerebral haemodynamics in a patient with Takayasu's arteritis who underwent carotid revascularisation. These techniques were found to be of clinical value for detection of cerebral hypoperfusion and assessment of the effects of therapeutic intervention.

Adult↗
PubMed1993

Protein-losing enteropathy due to secondary amyloidosis of the gastrointestinal tract.

A case of a 71 year old woman who experienced weight loss, diarrhea and edema due to protein-losing enteropathy caused by amyloidosis secondary to rheumatoid arthritis is described. Amyloid deposits were found in the systemic organs, specifically in the bowel. The arterioles were massively involved within the laminae propriae and many were narrowed considerably due to amyloid deposits. Ulcerative lesions, which were accompanied with the ruptured arterioles, were also found. Lymphangiectasia was present in the submucosa, subserosa and mesenterium. The mesenteric lymphatic vessels were deposited markedly with amyloid. The principal cause of the protein loss might be related to the increased capillary permeability to plasma proteins and the exudation through an inflamed mucosa. Functional disruption of the lymphatic flow in the bowel and mesenterium might also participate in the mechanisms of the protein loss. Evidence in this study supports the theory that lymphatic disorders in some patients with gastrointestinal amyloidosis are one of the important factors in the pathogenesis of protein-losing enteropathy.

Aged↗
PubMed1993

Expanded primary T nodules in the palatine tonsils from patients with IgA nephropathy.

We designed a study to investigate the morphological expression of immune responses in the palatine tonsils from patients with IgA nephropathy. To distinguish between the histological characteristics of the tonsils in habitual tonsillitis (47 patients) and IgA nephropathy (11 patients), we studied the T nodules, B-lymphoid follicles, germinal centers, areas of mixed T and B lymphocytes, lacunar epithelium and connective tissues; then we compared patients with habitual tonsillitis and IgA nephropathy. The T nodules in patients with IgA nephropathy were enlarged, and this change was not accompanied by atrophy of B-lymphoid follicles. Morphologically, primary T nodules were predominant. In reactive lymph nodes, T nodules generally play an important role in the extra-follicular maturation of stimulated B lymphocytes into Ig-secreting plasma cells. Therefore the enlarged primary T nodules remind us that this maturation may occur more frequently in the tonsils of patients with IgA nephropathy than in those with habitual tonsillitis. This suggests that some immunoregulatory dysfunction exists in the secretory immune system of mucosa-associated lymphoid tissues in patients with IgA nephropathy.

Adult↗
PubMed1993

Rapid and severe proteinuria induced in rats by antibody against cultured rat glomerular epithelial cells.

The aim of this study was to investigate the role of glomerular visceral epithelial cell (GEC) antigens in the induction of proteinuria. An antibody (anti-GECIg) was produced by rabbit immunization with membrane extracts prepared from a clonal GEC line, SGE1, from the isolated rat renal glomeruli. A one-shot intraperitoneal injection of anti-GECIg (day 0) induced rapid and severe proteinuria in rats, reaching a peak on day 2 (mean value, 425 mg/24h), then gradually decreased to normal levels by day 10. By direct immunofluorescence, fine granular binding of anti-GECIg along the glomerular capillary walls was observed within 24 h. Electron microscopy and immunoelectron microscopy revealed GEC alterations consisting of extensive retraction of the foot processes, vacuolar changes in the cytoplasm, microvillous transformation of the cell surface, and binding of anti-GECIg to the surface of the foot process, mainly to its soles. Two major components with Mr of 108,000 and 39,000 were identified by immunoblotting assay using SGE1 cell membrane extracts and anti-GECIg. This model of rat nephropathy induced by anti-GECIg hopefully will lead to a greater understanding of the mechanism by which proteinuria is induced and developed.

Animals↗
PubMed1993

Effects of seed saponins of Thea sinensis L. (Ryokucha saponin) on alcohol absorption and metabolism.

We evaluated the effects of the seed saponins of Thea sinensis L. on alcohol absorption and metabolism in rats and mice. An ethanolic extract from the seeds of T. sinensis was orally administered to the rats 1 hr before or 0.5 hr after administration of ethanol (2 g/kg), and the blood ethanol assayed 0.5, 1, 2, 3, and 4 hr after ethanol administration. The ethanol level decreased after both pre- and post-administration of the extract. The extract was further purified to obtain a saponin fraction which was orally administered to mice 1 hr before ethanol administration. Blood, liver, and stomach were obtained 0, 1, 3, and 6 hr after ethanol administration, and the ethanol, acetaldehyde, acetate, and acetone concentrations in each specimen were measured by head space gas chromatography. The saponin fraction decreased the ethanol levels in the blood and liver but increased that in the stomach five-fold over the control level, suggesting inhibition of alcohol absorption. The ethanol disappearance time from the blood was shortened, suggesting the promotion of alcohol disappearance. The acetate and acetone levels were unaffected. However, the acetaldehyde level decreased in the blood, liver, and stomach. The decreases in the ethanol and acetaldehyde levels in the liver suggested the protective effects of the seed saponins on the liver. The saponins did not directly inhibit hepatic alcohol dehydrogenase activity. The seed saponins of T. sinensis seem to suppress alcohol absorption by slowing gastric emptying and by inhibiting absorption across the cell membranes of the digestive tract.

Acetaldehyde↗
PubMed1993

Activating effects of phenolic compounds on the osteogenic cell line.

We examined four kinds of drugs for dental use for their ability to enhance DNA synthesis and the proliferation activity of cells by means of measuring 3H-thymidine uptake into cells. Three phenolic compounds; guaiacol, eugenol and phenol, and trioxane, the trimer of the paraformaldehyde complex, were examined. The effects of variations in concentration of lower doses of the dental drugs on subsequent uptake of 3H-thymidine were examined in osteogenic cells and fibroblastic cells. Osteogenic cells from human spongy bone, fibroblastic cells from human periodontal ligament, and mouse osteogenic MC3T3-E1 cells were used. 3H-thymidine uptake of osteogenic cells or fibroblastic cells was depressed in a concentration dependent manner by doses over 10(-6) M of the phenolic compounds. Over 10(-6) M, eugenol and guaiacol depressed the uptake of osteogenic cells or fibroblastic cells significantly and depressed it almost completely at doses over 10(-4) M. Phenol depressed the cells significantly over 10(-4) M. Trioxane depressed at all doses from 10(-4) M to 10(-16) M. The phenolic compounds enhanced the uptake of 3H-thymidine in a concentration dependent manner at doses below 10(-8) M of the phenolic compounds. The cells were enhanced in 3H-thymidine uptake maximally at 10(-12) M or 10(-14) M concentrations of the phenolic compounds.

3T3 Cells↗
PubMed1993

Cerebral vascular reactivity to carbon dioxide before and after cardiopulmonary bypass in children with congenital heart disease.

We examined cerebral vascular reactivity to carbon dioxide before and after cardiopulmonary bypass in 15 pediatric patients aged 2 to 9 years undergoing cardiac operations. Cerebral vascular reactivity was noninvasively assessed by transcranial Doppler ultrasonography. The cerebral blood flow velocity was plotted as a function of arterial carbon dioxide partial pressure. An exponential function was fitted for these plots and an exponent of curve was defined as the cerebral vascular reactivity to carbon dioxide. There was no significant change in this reactivity after cardiopulmonary bypass as compared with before bypass (before 0.028 +/- 0.003; after 0.030 +/- 0.016). For the entire series, we obtained best-fit curves of y = 2.8e0.046x (r = 0.91) and y = 3.4e0.031x (r = 0.89) (x; arterial carbon dioxide partial pressure, y; percent changes of cerebral blood flow velocity) before and after cardiopulmonary bypass. We conclude that the cerebral vascular reactivity to carbon dioxide was preserved before and after cardiopulmonary bypass in children undergoing cardiac operations. These results suggest that cerebral perfusion before and after cardiopulmonary bypass is not critically compromised.

Blood Flow Velocity↗
PubMed1993

Novel intercalators of pyrylium dye into double-stranded DNA.

Discovery is reported of novel intercalators without fused ring systems, pyrylium and thiopyrylium salt. 2-Methyl-4,6-bis-(N,N-dimethylaminophenyl) pyrylium salt 1 (Fig. 1) is, in particular, virtually non-fluorescent in aqueous solution, but form highly fluorescent complexes with double-stranded DNA (dsDNA), which yield more than 400 fold fluorescence enhancement at the peak emission. We report the synthesis, absorption and fluorescence properties of 1 and its thiopyrylium derivative 2 in comparison with other pyrylium 3, thiopyrylium 4 dyes and typical intercalator, ethidium bromide(EB). Compound 1 shows the absorption maximum at 540 nm and the red shift (about 40 nm) in the presence of dsDNA in similar to EB. The enhancement of fluorescence emission excited by visible light is extremely sensitive to the concentration of dsDNA comparing to that of EB. The thiopyrylium salt 2 with absorption maximum at 575 nm shows the similar profile in the absorption spectral shift and fluorescence enhancement to that of 1, when the dye binds to dsDNA.

Aniline Compounds↗
PubMed1993

[Clinico-pathological study of Helicobacter pylori in early gastric cancer].

The role of Helicobacter pylori (Hp) infection in the pathogenesis of various gastric diseases is an important but unresolved issue. To investigate the association between Hp and the histological findings of the stomach in patients of early gastric cancer, the prevalence of Hp in gastric mucosa and the mucosal alterations were examined histo-pathologically in the surgically resected stomach of 30 cases with early gastric cancer. Serum IgG antibodies for Hp were determined in these cases. All 30 cases had evidence of Hp infection in resected stomach and 90% had Hp antibodies in their serum. There was no evidence of direct association between Hp and gastric cancer histopathologically, although it is considered that chronic gastritis (atrophy and intestinal metaplasia) are implicated in Hp infection.

Adenocarcinoma↗
PubMed1993

Thrombopoietic effects of interleukin-6 in long-term administration in mice.

To further investigate the thrombopoietic and adverse effects of interleukin-6 (IL-6), 2 or 10 micrograms/day of recombinant human (rh) IL-6 was administered intraperitoneally (i.p.) to mice for up to 30 days. IL-6 increased platelet count, which plateaued at a level 30 to 40% higher than control after 5 days of treatment. This cytokine also maintained the high platelet count for the duration of treatment. The count exceeded normal levels 7 days after cessation of the 30-day treatment. IL-6 also induced a remarkable increase in the size but not the frequency of megakaryocytes in bone marrow sections. The number of bone marrow colony-forming units megakaryocyte (CFU-MK) and colony-forming units granulocyte-macrophage (CFU-GM) was not augmented by the administration of IL-6 in this protocol, while spleen progenitors were significantly stimulated. Small but significant increases did occur in the number of bone marrow megakaryocytes and CFU-MK, and in the proportion of CFU-MK in the DNA synthetic phase in mice treated with 10 micrograms/day of IL-6 for 30 days. Electron microscopic examination of bone marrow demonstrated that IL-6 remarkably developed the distribution of the demarcation membrane system (DMS) in mice treated for 30 days, with little change in mice treated for 5 days. The administration of 2 micrograms/day for 30 days induced a 2.2-fold increase in fibrinogen. No changes were observed in the hepatic or renal functions. Histologic and immunofluorescence studies on the kidneys revealed no significant changes compared with controls, indicating that proliferation of the glomerular mesangium did not occur. No neutralizing antibodies were detected in mice treated for 30 days. We conclude that the long-term administration of IL-6 in mice stimulates megakaryocyte maturation and platelet production with few adverse effects, and that this cytokine may be a candidate for the treatment of thrombocytopenia in humans.

Animals↗
PubMed1992

Roles of active oxygen species in glomerular epithelial cell injury in vitro caused by puromycin aminonucleoside.

The mechanism of puromycin aminonucleoside (PAN)-induced nephrosis has not yet been well defined. In the present study, we examined the protective effect of active oxygen scavengers on the PAN-induced injury of cultured rat glomerular epithelial cells (GECs) and the generation of active oxygen species in PAN-treated GECs. When exposed to PAN (greater than or equal to 25 micrograms/ml), cellular damage occurred in a time- and dose-dependent manner as evaluated by both the LDH release and MTT colorimetric assays. Concomitant addition of either the hydrogen peroxide (H2O2) scavenger, catalase, or the iron chelating agent, deferoxamine, to the culture medium caused a striking reduction of cellular injury. This suggested a role for H2O2 and for hydroxyl radicals (OH.) generated via the iron-catalyzed breakdown of H2O2 in PAN nephrosis. Using the scopoletin fluorescence assay, the release of H2O2 into the culture medium by GECs exposed to PAN (greater than or equal to 50 micrograms/ml) was shown to increase dose-dependently (greater than or equal to 57 +/- 11 pmol/4.4 x 10(6) cells per h, P less than 0.01) as compared with control cells (14 +/- 2 pmol/4.4 x 10(6) cells per h). These results strongly suggested that active oxygen species, especially H2O2 and OH., might play an important role in PAN-induced GEC injury in vitro as well as in vivo.

Animals↗
PubMed1992

Combination of epidermal growth factor and insulin is required for multicellular spheroid formation of rat hepatocytes in primary culture.

We showed that the combination of epidermal growth factor (EGF) and insulin is an essential supplement to Williams' #E medium for the formation of floating multicellular spheroids in primary culture of rat hepatocytes. Isolated hepatocytes assembled to form floating multicellular spheroids within 96 h through transient assembly of monolayer islands within the initial 24 h in dishes coated with liver-derived proteoglycans. However, the assembly of multicellular spheroids was severely suppressed in the absence of either EGF or insulin. The reduction of spheroid assembly was correlated with decreased attachment and subsequent decreased formation of monolayer islands within 24 h. The minimum amounts of EGF and insulin required for the formation of floating spheroids were 1 ng/ml and 0.4 microgram/ml, respectively. These results suggest that the enhancement of hepatocyte attachment provided by the combination of EGF and insulin during the early phase of culture is required for the formation of floating spheroids.

Animals↗
PubMed1992

Thyroid storm associated with probable subclinical hypoadrenocorticism in an elderly woman.

A 73-year-old woman was admitted to the hospital for severe persistent vomiting with fever, drowsiness, and weight loss. Elevated serum levels of thyroid hormones and the presence of a consciousness disorder with fever and vomiting led to the diagnosis of thyroid storm. A low normal concentration of serum cortisol, urinary 17-hydroxycorticosteroids and an elevated plasma level of corticotropin suggest that an inadequate adrenal reserve have been involved in the pathogenesis of the thyroid storm in this patient. She responded to the administration of intravenous methimazole and oral supersaturated potassium iodide solution.

17-Hydroxycorticosteroids↗