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Biomedical subjects

S Oguchi

Publications and source records attributed to S Oguchi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Improved hatching for in vitro quail embryo culture using surrogate eggshell and artificial vessel.

The establishment of avian embryonic culture is important both for the analysis of the developmental process and the establishment of transgenic chickens that produce useful biological materials in eggs. However, the hatchability of cultured embryos has been approximately 50%. We identified that the low rate of hatchability of cultured embryos was caused by limited oxygen and calcium availability. In quail embryo culture using chicken eggshell as a culture vessel, viability in the middle stage of culture was improved and 30% of embryos were hatched by oxygen enrichment. Furthermore, hatchability increased to 80% by supplementation with calcium lactate in addition to oxygen aeration. In the present study, a fully artificial vessel for quail embryo culture was designed using a gas-permeable Teflon membrane. By the addition of fine eggshell powder and calcium lactate, quail embryos grew and developed normally, and 43% of embryos hatched. Although the hatchability was lower than that of cultures using a surrogate eggshell, we achieved in hatching an avian embryo using a fully artificial vessel.

Animals↗
PubMed1998

Short-chain fatty acids regulate IGF-binding protein secretion by intestinal epithelial cells.

Gastrointestinal epithelial cells secrete insulin-like growth factor (IGF)-binding proteins (IGFBPs), which modulate the actions of IGFs on cell proliferation and differentiation. Short-chain fatty acids are bacterial metabolites from unabsorbed carbohydrate (including fiber). We hypothesized that they may alter the pattern of IGFBPs secreted by epithelial cells as part of a wider phenomenon by which luminal molecules regulate gastrointestinal epithelial cell signaling. The intestinal epithelial cell line, Caco-2, predominantly secretes IGFBP-3; however, butyrate increased the secretion of IGFBP-2 in a dose-dependent and reversible manner. Butyrate decreased the secretion of IGFBP-3. Butyrate altered only the synthesis and not the cell sorting of IGFBPs because 1) the secretion of IGFBPs remained polarized despite changes in their rates of production, and 2) IGFBP secretion corresponded to mRNA accumulation. The ability of short-chain fatty acids or the fungicide trichostatin A to stimulate IGFBP-2 correlated with their actions on histone acetylation. In conclusion, intestinal epithelial cells respond to short-chain fatty acids by altering secretion of IGFBPs.

Adenocarcinoma↗
PubMed1998

Chronic oral antigen exposure induces lymphocyte migration in anaphylactic mouse intestine.

Persistent diarrhea, vomiting, and dehydration are symptoms often seen in patients suffering from food allergy after chronic antigen exposure; however, the precise mechanisms involved have not been well defined. In an effort to clarify the mechanisms of the chronic intestinal changes attributable to genuine IgE-mediated anaphylactic reactions induced by orally administered antigen, a mouse model was established by s.c. implantation of a murine hybridoma capable of producing monoclonal anti-trinitrophenyl IgE antibody, and the morphologic and immunologic changes occurring in the intestine upon chronic antigen exposure were investigated. In the early stage after ingestion of the antigen, diarrhea and noticeable infiltration of mast cells as well as eosinophils into the lamina propria were observed. A substantial increase in serum histamine levels as well as an increase in leukotriene C4 synthesis in the jejunal mucosa were observed 1 h after antigen challenge. Also, the synthesis of leukotriene B4 was significantly elevated for up to 9 h after antigen challenge. The expression of both intercellular adhesion molecule-1 (ICAM-1) on mucosal vascular endothelial cells and IAd on epithelial cells was markedly enhanced, and noticeable infiltration of eosinophils and lymphocytes was also confirmed in the mouse model after chronic antigen exposure. These findings suggest that oral antigen exposure induces anaphylactic reactions in the intestine mediated by mast cells and eosinophils in response to the IgE-antigen complex in the early phase, and also induces lymphocyte migration after chronic antigen exposure.

Administration, Oral↗
PubMed1997

A case of infantile Dubin-Johnson syndrome with high CT attenuation in the liver.

We report a case of Dubin-Johnson syndrome (DJS) with severe infantile cholestasis and elevated computed tomography (CT) attenuation of the liver. Increased levels of urinary coproporphyrin I were found as well as pigment granules in the hepatocytes and hepatosteatosis. The CT attenuation was markedly higher in the liver of this patient at the ages of 3 and 7 months than in the spleen or kidneys. This high attenuation may be a finding specific to infantile DJS and, therefore, abdominal CT may be helpful in the diagnosis.

Biopsy, Needle↗
PubMed1997

The estimated incidence of cystic fibrosis in Japan.

BACKGROUND: It is believed that the incidence of cystic fibrosis (CF) among Asiatic races, including the Japanese, is very rare. This epidemiological study was carried out to investigate the incidence of CF in Japan. METHODS: We collected literature describing CF cases among pure Japanese and found 124 cases reported as CF during the 43 years from 1951, when the first case was reported, to 1993. Only 104 cases (57 male and 47 female patients) of 124 cases met our diagnostic criteria. RESULTS: A simple calculation based on the number of reported CF cases and of live births after 1980 suggested that the incidence of CF is about 1 in 350,000 in the Japanese population. Twenty-nine (27.9% of the total) of 30 patients diagnosed in the neonatal period presented symptoms of meconium ileus, an incidence higher than that reported for the white population. CONCLUSIONS: Our study results suggest that the incidence of CF in the Japanese population is even rarer than had been estimated before and that there is a genetic difference between northern European and Japanese populations.

Adolescent↗
PubMed1997

Reducing cell membrane n-6 fatty acids attenuate mucosal damage in food-sensitive enteropathy in mice.

Mucosal damage is commonly observed in food-sensitive enteropathy in infants, and the generation of leukotrienes is involved in the pathogenesis of this enteropathy. Because supplementing n-3 fatty acids is known to modify the production of leukotrienes, we investigated whether a change of dietary fatty acid composition affects leukotriene synthesis and food hypersensitivity reactions in the intestine by using a mouse model of food-sensitive enteropathy. The model was prepared by feeding ovalbumin to BALB/c mice after intraperitoneal injection of cyclophosphamide. Diets were prepared from soybean oil (control), perilla oil, lard, corn oil, and 0.125 volume of corn oil (low fat diet) and given to mice for 4 wk. Villous heights, crypt depths, leukotriene B4 and C4 production in the intestine were measured. Crypt hyperplasia and villous atrophy were severer in the corn oil-fed group than those of control group, whereas mucosal damage in the perilla oil and low fat diet groups was minimal. In the corn oil-fed group, red blood cell membrane levels of n-3 fatty acids were lower than the control, and the synthesis of leukotrienes was highest among all groups. In the perilla oil and low fat diet groups, n-6 fatty acids were lower than those of control group and leukotriene production was significantly suppressed. These results indicate that reducing cell membrane levels of n-6 fatty acids by feeding less n-6 fatty acids or supplementing n-3 fatty acids, is important to suppress leukotriene biosynthesis for prevention from mucosal damage in food-sensitive enteropathy.

Animals↗
PubMed1996

Selective increase of V beta 2+ T cells in the small intestinal mucosa in Kawasaki disease.

The current study tested the hypothesis that the gastrointestinal tract could be one of the primary sites of entry for etiologic agents in Kawasaki disease (KD). In an attempt to elucidate the pathogenic role of certain superantigenic agents in KD, T cell receptor V beta expression by T cells in the small intestinal mucosa of KD patients was investigated using MAb on frozen tissue sections. Twelve Japanese patients with KD and eight controls were enrolled in the study. The numbers of cells stained by an immunofluorescence from each study group were counted and analyzed statistically by the t test. The occurrence of V beta 2+ T cells was found to be selectively increased in the small intestinal mucosa of patients in the acute phase of KD compared with controls (p < 0.01). In our previous study, five kinds of streptococci and two kinds of staphylococci, not detected in control patients, were isolated from the lumen of the jejunum of KD patients. These data suggest that the increased occurrence of V beta 2+ T cells in the jejunal mucosa of KD patients may be caused by exotoxins acting as superantigens produced by bacteria colonizing the small intestinal mucosa of these patients.

Child, Preschool↗
PubMed1996

Microbiologic studies on the small intestine in Kawasaki disease.

In an attempt to elucidate the etiology of Kawasaki disease (KD), the microflora of the small intestine was investigated in 15 Japanese KD patients. The range of bacterial species adhering to the lumen of the jejunum of KD patients was quite different from that of controls. A wider variety of bacteria was isolated from jejunal biopsies in the acute phase of KD as compared with those from control children. Gram-positive cocci were isolated from KD patients predominantly. Notably, five kinds of streptococci and two kinds of staphylococci were isolated only from KD patients. Further investigation of the microflora of the small intestine of KD patients may provide clues to clarify the pathogenesis of this disease.

Child, Preschool↗
PubMed1996

Food antigen activates intraepithelial and lamina propria lymphocytes in food-sensitive enteropathy in mice.

Morphologic and immunologic changes in the gut mucosa of food-hypersensitive mice, from a study model generated by feeding ovalbumin (OVA) to female BALB/c mice after intraperitoneal injection of cyclophosphamide (CY), were investigated in an effort to clarify the mechanisms of food-sensitive enteropathy. Villous atrophy, crypt hyperplasia, and increased numbers of intraepithelial lymphocytes (IEL) were confirmed in the antigen-challenged OVA-sensitive mice as seen in food-sensitive enteropathy in humans, whereas no significant morphologic changes were observed in the nontreated control group or groups treated with OVA or CY alone. IEL and lamina propria lymphocytes (LPL) were isolated from the intestinal mucosa before and after the antigen challenge, and surface markers were analyzed by FACScan. After the antigen challenge, the numbers of CD8+ cells increased among the IEL, and the occurrence of both CD4+ and CD8+ cells increased among the LPL. The numbers of Thy-1+ cells and TCR- alpha/beta + cells increased among both the IEL and LPL, and LFA-1 expression was enhanced in both of these lymphocyte populations. The proliferative response of IEL and LPL to OVA increased in a dose-dependent manner after the antigen challenge in the OVA-sensitive mouse model. These results indicate that IEL and LPL, possibly those that have migrated from peripheral blood, are activated by orally administered antigens and cause mucosal damage in the food-sensitive enteropathy.

Animals↗
PubMed1995

Quantitative analysis and immunohistochemical studies on small intestinal mucosa of food-sensitive enteropathy.

Quantitative analysis and immunohistochemical studies of small intestinal mucosa were performed to investigate the mechanism of mucosal damage in 10 patients with food-sensitive enteropathy. Jejunal biopsy specimens were taken before and after treatment and after clinical relapse following a challenge test. The low villous height of untreated patients normalized after introduction of an elimination diet but declined again to subnormal level after a challenge test. Several other types of cells were significantly increased in the untreated patients in comparison to controls. These included HLA-DR+ (DR+) CD4+ cells in the lamina propria and intraepithelial CD8+ cells. Moreover, those cell patterns, such as increased DR+ CD4+ cells and CD8+ cells, normalized with treatment but regressed to pretreatment levels when the patients were challenged. These findings suggest that activated CD4+ cells in the lamina propria of the small intestinal mucosa, probably by releasing cytokines, may play an important role in contributing to mucosal damage in patients with food-sensitive enteropathy.

Animals↗
PubMed1995

Differentiation and polarity alter the binding of IGF-I to human intestinal epithelial (Caco-2) cells.

This study examined whether insulin-like growth factor-I (IGF-I) bound to specific functioning IGF receptors on the surface of Caco-2 cells and how this binding was affected by the differentiation and polarity of these cells. IGF-I, which increased cell proliferation in a dose-dependent manner, bound to a specific receptor on the surface of Caco-2 cells. Affinity cross-linking with labeled IGF-I followed by reducing sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed M(r)s at 135,000, 270,000 and 355,000 bands, which was inhibited by unlabeled IGF-I. A Scatchard analysis of radioligand-receptor binding showed the presence of a single class of receptors with high affinity for IGF-I. This class of receptors was specific for IGF-I, the affinity of IGF-I to the receptor being four and 150 times greater than IGF-II and insulin, respectively. There was no difference in the affinity of IGF-I to type 1 IGF receptors between less-differentiated [dissociation constant (Kd) = 3.81 nM] and well-differentiated cells (Kd = 3.78 nM); however, well-differentiated cells showed a 2.4-fold higher maximum number of binding sites (Bmax) than less-differentiated cells (3.45 vs. 1.44 x 10(4) sites/cell), indicating an increase in the density of IGF-I receptors with differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1995

Patterns of 24 h intragastric acidity in duodenal ulcers in children: the importance of monitoring and inhibiting nocturnal acidity.

The objective of this study was to compare the gastric acidity patterns of patients with duodenal ulcers and normal children. Eight patients with duodenal ulcer had their intragastric pH monitored for two consecutive 24 h periods using intragastric glass electrodes. The first 24 h period elucidated pH patterns in the absence of treatment and the second period evaluated the acid suppressive effect of 15 mg/kg of cimetidine when given in three divided doses. Results showed that the ulcer patients were hyperacidic, particularly at midnight. This finding was in marked contrast to the results obtained in the study of normal controls. The mean pH of normal children was above 3 around midnight. This phenomenon is known as intragastric pH inversion. The mean pH 3 time (the cumulative duration of the time for which gastric pH is maintained at > or = pH 3) was significantly shorter in patients with ulcers. However, pH 3 time of these patients significantly increased throughout the 24 h recording period during the daytime and at night after the introduction of cimetidine. This resulted in an induction of apparent nocturnal intragastric pH inversion for the ulcer patients. This study demonstrates the usefulness of 24 h continuous intragastric pH monitoring in children. The data showed that there was a pattern of gastric hyperacidity in pediatric ulcer patients which is clearly distinct from that of normal children, particularly in the patterns occurring at midnight. Cimetidine at 15 mg/kg per day in three divided doses was effective in suppressing secretion even at night.

Adolescent↗
PubMed1995

Helicobacter pylori colonization in children with peptic ulcer disease. III. Diagnostic value of the 13C-urea breath test to detect gastric H. pylori colonization.

The efficiency of the 13C-Urea Breath Test (13C-UBT) for the detection of Helicobacter pylori colonization in gastric mucosa was evaluated. The 13C-UBT was performed in five pediatric and six adult subjects who had had upper gastrointestinal endoscopy within 2 weeks. H. pylori colonization was confirmed in two pediatric and three adult subjects with peptic ulcer combined with antral gastritis, by histological examination of antral biopsy specimens. When an individual with H. pylori colonization ingested a solution containing 13C-urea, a significant amount of 13CO2 appeared in the respiratory CO2 within 10 min. The mean cumulative percentage dose of 13C recovered in the breath over 30 min in the cases with H. pylori colonization was significantly higher than that in those who were not colonized (4.91 vs 0.41, P < 0.001). In addition, the effect of antibiotic on the eradication of H. pylori from gastric mucosa was monitored by 13C-UBT in two cases. The values of cumulative percentage dose of 13C over 30 min fell to the same levels as those observed in H. pylori negative subjects after just 2 weeks treatment with amoxicillin; however, positive results were obtained again 1 month after the withdrawal of amoxicillin. In summary, 13C-UBT is a simple, reliable, non-invasive method in the diagnosis of gastric H. pylori colonization especially for pediatric patients.

Adolescent↗
PubMed1995

Iron saturation alters the effect of lactoferrin on the proliferation and differentiation of human enterocytes (Caco-2 cells).

Recent studies have indicated that lactoferrin may act as a cell mitogen. The effect of human and bovine lactoferrins on the proliferation and differentiation of a human intestinal epithelial cell line (Caco-2) was investigated and compared with that of human transferrin. Caco-2 cells were cultured in serum-free media supplemented with both iron-unsaturated and -saturated forms of the iron-binding proteins. Cell proliferation and differentiation were evaluated by examining growth curves and measuring sucrase and alkaline phosphatase activities of brush border membrane fractions, respectively. The iron-binding status of lactoferrins and transferrin affected the proliferation of Caco-2 cells. The iron-saturated forms of human (S-hLf), bovine (S-bLf) lactoferrins and human transferrin (S-hTf) enhanced cell proliferation, while iron-unsaturated forms (U-hLf, U-bLf, and U-hTf) suppressed it. Iron-binding status also determined the effect of lactoferrin and transferrin on cellular differentiation, but this effect differed for different brush border enzymes. S-hTf enhanced sucrase activity more than S-hLF or S-bLf. Both U-hLf and U-bLf markedly suppressed sucrase activity. U-hTf suppressed alkaline phosphatase activity appreciably, while the other iron-binding proteins showed no significant effect on it. Lactoferrin and transferrin may modulate the proliferation and differentiation of intestinal epithelial cells, but their efficacy depends on their saturation with iron.

Animals↗
PubMed1995

In vivo observation of magnified features of pigmented lesions on volar skin using video macroscope. Usefulness of epiluminescence techniques in clinical diagnosis.

BACKGROUND AND DESIGN: In vivo epiluminescence microscopy is now used as a useful noninvasive method for determining clinical diagnosis of pigmented skin lesions. Until now, however, pigmented lesions on the volar skin have been hardly studied with this method. In the present epiluminescent study, various kinds of pigmented lesions on the volar skin were extensively investigated by means of video macroscope, a newly developed electronic device with a higher magnification power, and correlation between the magnified features and histopathologic findings was evaluated. RESULTS: Magnified features of most lesions of acquired or congenital melanocytic nevus on the volar skin were classified into the following three typical patterns: (1) a parallel pattern formed by pigmented parallel lines corresponding to the furrows of the skin markings, (2) a latticelike pattern composed of pigmented lines along and across the furrows of the skin markings, and (3) a fibrillar pattern formed by densely packed, fibrillar pigmented lines arranged in the direction crossing the furrows. In contrast, macular or plaque portions of acral lentiginous melanoma exhibited disorderly arranged, irregular pigment patterns, mainly affecting the ridges of the skin markings. In addition, brown globules of various shades and many black dots of variable sizes were often observed and, on the margin of the lesions, pseudopods and/or the "serrated" pattern were detected. Cutaneous hemorrhagic macule and so-called black heel showed highly specific features and thus could be easily diagnosed with video macroscopy. CONCLUSION: Video macroscope proved to be a very useful instrument for the diagnosis of pigmented lesions on the volar skin.

Equipment Design↗
PubMed1994

Dual mechanism for the control of inducible-type NO synthase gene expression in macrophages during activation by interferon-gamma and bacterial lipopolysaccharide. Transcriptional and post-transcriptional regulation.

Production of nitric oxide (NO) by macrophages is enhanced upon activation by bacterial endotoxins and cytokines mainly via an increase of the intracellular content of the inducible isoform of nitric oxide synthase (i-NOS). We have studied in detail the effect of several modulators of macrophage activity on steady state levels of i-NOS mRNA in the mouse macrophage-like cell line RAW 264.7. Bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) were found to be effective inducers of i-NOS mRNA, in accordance with their known ability to stimulate both i-NOS activity and NO production in macrophages from different sources, while TNF-alpha, IL-1, or IL-6 was ineffective in this regard. Accumulation of i-NOS mRNA in response to either LPS or IFN-gamma stimulation was accompanied by increased i-NOS gene transcription, as detected both by using a nuclear "run-on" transcription assay and by transient transfection of the cloned gene promoter in RAW 264.7 cells. Co-stimulation of the cells with both inducers resulted in higher steady state levels of i-NOS mRNA in the absence, however, of a corresponding potentiation of the rate of gene transcription. This was due primarily to a considerable effect of LPS on i-NOS mRNA stability, with prolongation of its half-life from 1-1.5 h, in the presence of IFN-gamma alone, to 4-6 h in the presence of both LPS and IFN-gamma.

Amino Acid Oxidoreductases↗
PubMed1994

Enhancement of inducible-type NO synthase gene transcription by protein synthesis inhibitors. Activation of an intracellular signal transduction pathway by low concentrations of cycloheximide.

Treatment of mouse macrophage-like RAW 264.7 cells with certain protein synthesis inhibitors is followed by accumulation of the mRNA for the inducible isoform of nitric oxide synthase (i-NOS). The activity of these compounds on the i-NOS gene in RAW 264.7 cells was analyzed here in detail. Results show that both cycloheximide and anisomycin can efficiently induce i-NOS mRNA, even when used at concentrations so low (0.25 microgram/ml) to have only negligible effects on protein synthesis; puromycin, on the other hand, shows only a limited effect on i-NOS mRNA expression, detectable only when cells are treated with higher concentrations of inhibitor (25 micrograms/ml). In RAW 264.7 cells, low concentrations of cycloheximide trigger an immediate-early gene response, as indicated by induction of c-fos and JE mRNAs, and can efficiently activate transcription of transiently transfected recombinant reporter genes including either the i-NOS or the c-fos gene promoters.

Amino Acid Oxidoreductases↗