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Biomedical subjects

S Iwata

Publications and source records attributed to S Iwata.

At least 325 records · Page 18Linked to original sources
PubMed1988

In vitro study on corneal permeability to bunazosin.

Corneal permeability of bunazosin, one of the alpha-adrenergic receptor antagonists, was investigated in vitro using excised rabbit cornea mounted on a corneal permeability apparatus, and the enhancing effects of various acids on the permeability of bunazosin were evaluated. Caprylic and capric acid elevated octanol/water partition coefficient of bunazosin, and corneal permeability was increased, probably as a result of ion-pair formation between them. Neither bunazosin, these acids, or the ion-pair caused corneal swelling. These acids, in contrast, had little effect on the partition of pilocarpine, or on corneal permeability.

Adrenergic alpha-Antagonists↗
PubMed1988

Corneal permeability to bunazosin in rabbits.

Topical and systemic absorption of bunazosin after topical instillation was investigated in rabbits. Corneal permeability of bunazosin in vivo was increased by the addition of caprylic acid in amounts equimolar to bunazosin. Aqueous humor levels of bunazosin were significantly elevated. These results correlated well with those obtained in vitro experiments. Contrarily, the levels of plasma were not significantly affected and only slightly lowered by caprylic acid.

Adrenergic alpha-Antagonists↗
PubMed1988

Studies on improved corneal permeability to bunazosin.

Various factors influencing corneal permeability to bunazosin were investigated. The permeability of the cornea to bunazosin increased with increasing pH, either in the presence or absence of caprylic acid; the permeability to bunazosin and the partition of bunazosin were both enhanced by caprylic acid and both enhancements became maximal when the molar ratio of bunazosin: caprylic acid became unity; the permeability to methylparaben, a non-ionic permeant, was not increased by caprylic acid or capric acid and the permeability was not increased by the pretreatment of the cornea with caprylic acid. Furthermore, protein-bunazosin interaction was not affected by caprylic acid. The present results suggest that the enhancement of permeability caused by caprylic acid is attributable only to the increased partition of bunazosin to the corneal membrane.

Adrenergic alpha-Antagonists↗
PubMed1988

[The pathological study of enterosiderosis in guinea pigs].

Enterosiderosis in both SPF Hartley guinea pigs and vitamin C-deficient animals of the same strain were studied by light and electron microscopy. Enterosiderosis was detected in all animals in the present study. Macrophages, inclosing yellowish-brown pigments and erythrocytes, appeared in the lamina propria of the intestinal mucosa, mainly in the cecum. These pigments in the macrophages were positive for Prussian blue, PAS and the Nile blue reaction. Residual bodies containing highly electron-dense ferritin-like particles, lipofuscin granules and debris of phagocytized erythrocytes were found by electron microscopy in the macrophages. In vitamin C-deficient guinea pigs, the number of macrophages, including the same above pigments, appeared in the lamina propria of the intestinal mucosa, and there was severe enterosiderosis. In the absorptive cells of the intestinal mucous membrane, granules positive for the Prussian blue reaction appeared only in the duodenum. These findings strongly suggest that the pigments in the macrophages in enterosiderosis of the guinea pigs were mixtures of iron and lipofuscin granules and that the iron is derived from erythrocytes phagocytized by macrophages in the lamina propria, but not from iron absorbed by epithelial cells.

Animals↗
PubMed1988

[Bacteriological and clinical evaluations of imipenem/cilastatin sodium in neonates and premature infants].

The antimicrobial activity of imipenem against group B streptococci was investigated. The clinical efficacy of imipenem/cilastatin sodium (IPM/CS) was determined in neonates and premature infants. The results are summarized below. 1. The distribution of MIC values of IPM against 55 clinical isolates of group B streptococci isolated from the vagina of pregnant women peaked at 0.024 micrograms/ml. MIC values of IPM against all clinical isolates tested were 0.05 microgram/ml or less. 2. IPM/CS was used for treatment of bacterial infections in 9 neonates and premature infants. Among these patients, clinical responses were excellent in 5 patients and good in 4 patients. No adverse reaction was observed. Abnormal laboratory test values were observed in 4 patients, eosinophilia in 2 patients and increased platelets in 2. 3. In 7 neonates and premature infants, quantitative cultures for aerobic and anaerobic fecal flora were performed. Fecal flora change was not significantly different than those observed during treatment with latamoxef or cefmenoxime. 4. Ten neonates and premature infants were investigated for effects of IPM/CS on the blood coagulation system. Prolongations of prothrombin time (PT) and activated partial thromboplastin time (APTT) were observed in 1 patient. Abnormal prothrombin (PIVKA II) was detected in the same patient. There was no tendency for inhibition of platelet function.

Bacteria↗
PubMed1988

[Synchronously occurring transitional cell carcinoma of the ureter with adrenocortical carcinoma].

A sixty eight-year-old man was admitted to our hospital complaining of macroscopic hematuria. Ultrasonography, X-ray and laboratory examination revealed a right ureter tumor and left non-functioning adrenal tumor. Pathological diagnosis was transitional cell carcinoma of the ureter and left adrenocortical carcinoma. A review of persistent Japanese literature revealed this case to be the 97th case of non-functioning adrenocortical carcinoma and the first case synchronously occurring with transitional cell carcinoma of the ureter. Forty eight cases of synchronously occurring transitional cell carcinoma of the ureter with cancers in other organs, especially renal cell carcinoma and gastric cancer, have been reported. Recently, an increasing number of cases of non-functioning adrenal carcinoma are detected by CT scan, ultrasonography, adrenal radioisotopic scintigraphy and urinary 17-OHCS, 17-KS.

Adenocarcinoma↗
PubMed1988

Effect of tannin on oxidative damage of ocular lens.

The protective effect of geraniin (tannin from Geranium thunbergii) against oxidative damage was examined in the mouse ocular lens. Oxidative damage in the lens was induced by diamide, diazene dicarboxylic acid bis (N,N-dimethylamide); diamide oxidized the sulfhydryl groups in both the membrane and cytoplasm but did not increase lipid peroxide. Geraniin showed protective effects on the changes in the Na+/K+ ratio, GSH level, Na,K-ATPase activity, GSH reductase activity and the sulfhydryl level of the membranous protein in the diamide-treated lens, but such protective effects of geraniin were not observed in the cell-free system of the lens. In addition, geraniin itself was unable to reduce GSSG to GSH and also unable to inhibit the oxidative reaction of the sulfhydryl group to diamide. These results suggest that in the intact lens geraniin would act primarily on the lens cell membrane surface to inhibit an influx of diamide into the inner part of the plasma membrane and the cytoplasm, and consequently that geraniin may protect sulfhydryl groups in the cell membrane and cytoplasm from their oxidation by diamide and keep the redox system of the lens in a normal state.

Animals↗
PubMed1988

[An experimental endoscopic study on intestinal ischemic lesions in dogs with special reference to fluorescence endoscopy].

In order to clarify the pathophysiology of intestinal ischemic lesions and to make a useful method for the prediction of fate of the ischemic bowel, we devised an experimental model to produce the disorder. Microbarium of 0.5 micrometer in diameter was injected into a branch of the superior mesenteric artery of adult mongrel dogs. The severity of the ischemic lesions depended on the amount of microbarium injected, and lesions could be classified into three types; transient, stricturing and gangrenous, similar to clinical cases. Endoscopic examination was performed, accompanied with fluorescence endoscopy. Fluorescein could not be observed in all types soon after microbarium injection. In the transient type, fluorescein was observed after only a few days in an evenly distributed pattern. However in the stricturing type, the appearance of fluorescein was delayed, and an irregular pattern was observed in about 1 week. The submucosal blood flow was measured by hydrogen clearance method. The fluorescence endoscopic findings were nearly compatible with changes of submucosal blood flow. Fluorescence endoscopy is easily performed and appears to be highly useful in the differentiation of these three types of ischemia in the early stages.

Animals↗
PubMed1988

[Clinical studies in sultamicillin fine granule in the field of pediatrics].

Clinical studies were carried out on sultamicillin (SBTPC) fine granule in the field of pediatrics. The results obtained are summarized below. 1. Thirty children with bacterial infections were treated with SBTPC fine granule. The clinical results were excellent in 24 and good in 5, with an efficacy rate of 96.7%. 2. Bacteriological screening identified 26 pathogenic organisms of which 14 were Gram-positive cocci and 12 Gram-negative rods. Eradication rates were 91.7% in Gram-positive cocci and 66.7% in Gram-negative rods. 3. As side effects, diarrhea was observed in 12.9%, loose stool in 16.1% and eosinophilia in 3.2% of the patients. From the above results, it appeared that SBTPC fine granule was a useful drug for treating bacterial infections in the field of pediatrics.

Adolescent↗
PubMed1988

[Influence of sultamicillin on intestinal bacterial flora].

Effects of sultamicillin (SBTPC) fine granules, a new oral beta-lactam antibiotic, on the intestinal bacterial flora were studied in tetra-contaminated mice and in pediatric patients. SBTPC was administered at a dose of 100 mg/kg once a day for 5 consecutive days to mice contaminated with 4 different species of organisms: Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifidobacterium breve. In all of the 4 species, bacterial populations in feces were markedly reduced on days 4 to 5 after the start of the treatment. Subjects in the pediatric study were 5 children with bacterial infections (4 boys and 1 girl) at ages from 1 year 3 months to 10 years 8 months and with their body weight ranging from 11.8 kg to 35.0 kg. SBTPC fine granule was administered at a dose of 10 mg/kg 3 to 4 times a day for 4 to 7 days. Although there were some variations in the fecal bacterial flora noticed among these subjects during the treatment, populations of main aerobes and anaerobes such as Enterobacteriaceae, Enterococcus, Bacteroides and Bifidobacterium decreased markedly in all cases. These decreases were more pronounced for anaerobes and total numbers of anaerobes were markedly reduced in all cases. Glucose non-fermenting Gram-negative rods and fungi tended to increase with administration of SBTPC fine granule. Although these changes tended to return to pre-dosing state after the cessation of the treatment with SBTPC fine granule, attention must be paid to possible occurrences of diarrhea, superinfection or bleeding tendency when treatment with the drug is continued for a long period of time. Fecal concentrations of both ampicillin and sulbactam during SBTPC fine granule treatment showed relatively high values except 1 sample with a high beta-lactamase activity in feces. These high concentrations suggest the possibility of biliary excretion of absorbed drugs and the possibility of hydrolysis of SBTPC in the intestine due to high pH. Fecal concentrations of the drug also appeared to be closely related to beta-lactamase activity in feces.

Ampicillin↗
PubMed1988

[Fundamental and clinical evaluations of ceftriaxone in neonates].

The antibacterial efficacy of ceftriaxone (CTRX) against group B Streptococcus and its clinical efficacy in newborns were examined, and the results obtained are summarized as follows. 1. MIC's of CTRX against 55 strains of B group Streptococcus from the pregnant vagina were 0.10 micrograms/ml or lower. 2. Efficacies of CTRX were good to excellent in 8 cases administered for treatment, 3 cases for prophylaxis and 1 for observation of adverse reactions. Observed adverse reactions included diarrhea in 4 cases and vomiting in 2 cases. As abnormal laboratory parameters, eosinophilia and thrombocytosis were observed in 1 case each. 3. An examination of intestinal bacteria in 9 cases revealed that CTRX gave as much influence to the flora as other third-generation cephems. 4. An examination for the vitamin K deficiency in 11 cases found a prolongation of prothrombin time (PT) in 3 cases and protein induced by vitamin K absence (PIVKA) II positive in 2 cases. 5. Testing of platelet aggregation with adenosine diphosphate (ADP) in 7 cases showed little influence of CTRX.

Ceftriaxone↗
PubMed1987

Vascularizing the ischemic jejunum by intra-seromuscular implantation of a gastroepiploic vascular pedicle--an application of experimental esophageal reconstruction.

Many experimental studies have been done in an attempt to feed various ischemic organs. Of these, both direct intraorganic vascular implantation, and vascular anastomosis, appear to show promise for vascularizing the ischemic gastrointestinal tracts. Preliminary experiments were done in 24 Mongrel dogs to establish the blood flow of the jejunum by direct epiploic vascular pedicle implantation. Morphological development of the communicating vascular system, newly formed between the implanted epiploic vessel and the indigenous vascular network of the jejunum, was clarified by microangiography and histology. In 20 dogs, esophageal reconstruction was successfully accomplished, using the jejunal loop vascularized as described above. The total length of the jejunal segment, and the esophagojejunal anastomotic portion, had neither signs of circulatory disturbance nor necrosis, one, three and twelve months post-operatively. Our experimental findings suggest that direct vascular implantation is the simplest way to vascularize the ischemic intestinal tract and may also be applicable widely in the field of abdominal surgery.

Animals↗