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Biomedical subjects

Y Mikami

Publications and source records attributed to Y Mikami.

At least 253 records · Page 14Linked to original sources
PubMed1990

Endogenous Nocardia asteroides endophthalmitis in a patient with systemic lupus erythematosus.

We report a case of endogenous Nocardia endophthalmitis in a patient with systemic lupus erythematosus (SLE). He developed a parafoveal lesion in the right fundus while on systemic corticosteroid and antibiotic treatment. Initially we suspected a fungal origin and treated him with antifungal drugs. The intraocular disease progressed without improvement and advanced to the vitreous cavity. Nocardia asteroides was found in a specimen obtained at pars plana vitrectomy and was also cultured from the same specimen. The intraocular infection was controlled by antibacterial drugs, though the visual acuity of the right eye was reduced to only light perception owing to heavy vitreous opacity and secondary cataract. This case is the first report of endogenous Nocardia endophthalmitis in Japan and also the first case of this disease reported from outside the United States of America.

Adult↗
PubMed1990

Relationship between gastrin cell number, serum, antral mucosa and luminal gastrin concentration and gastric acidity in antral atrophic gastritis.

The aim of our study was to investigate the relationship between gastrin producing cell density with antral mucosa, luminal and serum gastrin concentration in antral atrophic gastritis. Our study group consisted of 17 patients: six with mild atrophic gastritis, seven with moderate atrophic gastritis and four with severe atrophic gastritis. None of the patients had type-A atrophic gastritis but the body mucosa was affected by superficial gastritis at various extent in some. A group of 15 healthy subjects served as control. All subjects underwent gastroscopic examination with multiple bioptic sampling. Radioimmunoassay was used for gastrin determination and photomicroscopy for gastrin producing cell density assessment. Electron microscopy was used to assess the gastrin producing granule density index. Patients with moderate and severe atrophic gastritis showed a lower gastric acidity and acid output as compared to control. Serum gastrin did not show significant differences among the groups. In moderate and severe atrophic gastritis, gastrin producing cell granule density index, gastrin producing cell density and antral mucosa gastrin concentration were significantly lower when compared with control and decreased with advancing of the severity of atrophic gastritis. In atrophic gastritis, however, the latter two measurements were not correlated. In moderate and severe atrophic gastritis luminal gastrin concentration significantly increased, compared with control, after the severity of atrophic gastritis. Gastrin producing cell granule density index and luminal gastrin concentration showed a significant correlation with gastric pH. These data suggest that in antral atrophic gastritis with reduced gastric acidity, the decrement of gastrin producing cells is followed by gastrin producing cell hyperfunction with increased luminal release of gastrin.

Adult↗
PubMed1990

Defect in tyrosine kinase activity of the insulin receptor from a patient with insulin resistance and acanthosis nigricans.

We report here a defect in tyrosine kinase activity of the insulin receptor from an insulin-resistant patient with acanthosis nigricans using cultured Ebstein-Barr virus (EBV)-transformed B-lymphocytes. As judged by affinity labeling and immunoblotting, the alpha- and beta-subunits of insulin receptors from the patient's lymphocytes exhibited the same mol wt as those from control subjects. Lectin-purified extracts from lymphocytes of the patient and the control subjects containing the same insulin-binding capacity were assayed for autophosphorylation and the ability to phosphorylate histone H2B. The degree of insulin-dependent autophosphorylation and the tyrosine kinase activity of the insulin receptor from the patient's lymphocytes were decreased to 15% and 13%, respectively, in a cell-free system. The insulin-dependent autophosphorylation of the insulin receptor was also impaired in intact EBV lymphocytes from the patient. Consistent with these results, we found that one of this patient's alleles had a mutation in which valine is substituted for Gly996, the third glycine in the conserved Gly-X-Gly-X-X-Gly motif in the kinase domain. Thus, it seems likely that the defect in tyrosine kinase activity of the insulin receptor cause the insulin resistance in this patient. The EBV lymphocyte can be a good system to detect genetically determined abnormalities in the insulin receptor.

Acanthosis Nigricans↗
PubMed1989

Human diabetes associated with a mutation in the tyrosine kinase domain of the insulin receptor.

Insulin receptor complementary DNA has been cloned from an insulin-resistant individual whose receptors have impaired tyrosine protein kinase activity. One of this individual's alleles has a mutation in which valine is substituted for Gly996, the third glycine in the conserved Gly-X-Gly-X-X-Gly motif in the putative binding site fo adenosine triphosphate. Expression of the mutant receptor by transfection into Chinese hamster ovary cells confirmed that the mutation impairs tyrosine kinase activity.

Alleles↗
PubMed1989

Paecilotoxin production in clinical or terrestrial isolates of Paecilomyces lilacinus strains.

The production of paecilotoxin from various isolates of Paecilomyces lilacinus was studied using three different media and high performance liquid chromatography (HPLC). Alkaline medium was found to be suitable for the production of the toxins. Among 20 strains tested, 19 including four clinical isolates were found to produce the toxins. Production patterns of paecilotoxins were very similar in each strain and the main toxins were A and B.

Amino Acid Sequence↗
PubMed1989

In-vitro activity of flomoxef, a new oxacephem group antibiotic, against Nocardia in comparison with other cephalosporins.

The susceptibility of 113 strains of pathogenic Nocardia, N. asteroides, N. farcinica, N. nova, N. brasiliensis and N. otitidiscaviarum to a new oxacephem antibiotic flomoxef was determined by an agar dilution method in comparison with those of 13 other cephalosporins. Flomoxef was two to 50 times more active against these pathogenic Nocardia than other cephalopsorins tested. However, there were differences in susceptibility to this antibiotic among these Nocardia strains. N. asteroides was the most sensitive species, followed by N. farcinica and N. nova. N. brasiliensis was moderately sensitive and N. otitidiscaviarum was resistant.

Cephalosporins↗
PubMed1989

In vitro susceptibility of Nocardia spp. to a new fluoroquinolone, tosufloxacin (T-3262).

The in vitro activity of a new fluoroquinolone, tosufloxacin (T-3262), against 111 pathogenic Nocardia strains was studied by an agar dilution method and compared with the activities of other fluoroquinolones. All strains were susceptible to tosufloxacin, and the drug was 2 to 20 times more active than four other quinolones tested. Nocardia farcinica was the Nocardia species most susceptible to tosufloxacin.

4-Quinolones↗
PubMed1989

[Study of ultrasonography applied to dental diagnosis. Examination of gingival morphology including epulis in relation to root surface].

Examination of gingival morphology was conducted using ultrasonic imaging equipment in a 57-year-old female with epulis. The ultrasonogram showed external gingival morphology including epulis and root surface caries which was difficult to detect because of masking by gingival enlargement. It appears that ultrasonograms are useful not only in examining gingival morphology but also in detecting changes in root surfaces hidden by the gingiva.

Female↗
PubMed1989

[In vitro susceptibility of pathogenic Nocardia to beta-lactam antibiotics, especially imipenem, a carbapenem antibiotic].

In vitro antibacterial activity of 30 beta-lactam antibiotics including 2 beta-lactamase inhibitors (clavulanic acid and sulbactam) against 2 major pathogenic Nocardia, i.e. Nocardia asteroides group and Nocardia brasiliensis was studied. Among the antibiotics tested, a newly developed carbapenem antibiotic, imipenem (IPM), was found to be the most active, followed by oxacephem group antibiotic flomoxef (FMOX). IPM exhibited activity against only N. asteroides group (N. asteroides, Nocardia farcinica and Nocardia nova). On the other hand, FMOX showed activity against all pathogenic Nocardia tested. A 2- to 30-fold decreases in minimum inhibitory concentration (MIC) for N. asteroides, N. brasiliensis and N. farcinica was noted when antibiotics and beta-lactamase inhibitors were combined compared to antibiotics alone. Further combination and enzymatic studies indicated that all pathogenic Nocardia possess beta-lactamase except for a half of the strains of N. nova. These species' specific sensitivity patterns of pathogenic Nocardia are discussed in this paper with references to their taxonomic positions.

Anti-Bacterial Agents↗
PubMed1988

Microbial Conversion of alpha-Ionone, alpha-Methylionone, and alpha-Isomethylionone.

alpha-Ionone, alpha-methylionone, and alpha-isomethylionone were converted by Aspergillus niger JTS 191. The individual bioconversion products from alpha-ionone were isolated and identified by spectrometry and organic synthesis. The major products were cis-3-hydroxy-alpha-ionone, trans-3-hydroxy-alpha-ionone, and 3-oxo-alpha-ionone. 2,3-Dehydro-alpha-ionone, 3,4-dehydro-beta-ionone, and 1-(6,6-dimethyl-2-methylene-3-cyclohexenyl)-buten-3-one were also identified. Analogous bioconversion products from alpha-methylionone and alpha-isomethylionone were also identified. From results of gas-liquid chromatographic analysis during the fermentation, we propose a metabolic pathway for alpha-ionones and elucidation of stereochemical features of the bioconversion.

Journal Article↗
PubMed1988

Structural studies on minor components of saframycin group antibiotics saframycins F, G and H.

Three minor components of saframycin group antibiotics, saframycins F, G and H were isolated and their structures were determined by comparison with the spectral data of UV, IR, and 1H and 13C NMR of already reported saframycins A and D. Saframycins F, G and H were 21-cyanosaframycin D, 14-hydroxysaframycin A and 25-dihydro-25-beta-ketopropyl-saframycin A, respectively.

Anti-Bacterial Agents↗
PubMed1987

Gastric submucosal tumours of neurogenic origin with neuroaxonal and Schwann cell elements.

Twelve cases of gastric submucosal tumours, originally diagnosed as leiomyoma and leiomyosarcoma, were investigated by staining with the neurogenic markers S-100 and neuron specific enolase (NSE). Three cases were, in addition, studied by electron microscopy. The tumours stained negatively for desmin, indicating that they were not of smooth muscle origin. All stained positively for S-100 and NSE. The ultrastructural features in the cases examined by electron microscopy were reminiscent of autonomic nerve structures normally present in the gastric wall. These included fine cytoplasmic processes of Schwann cells, wrapped with complete or incomplete basement membranes, and structures analogous to post-ganglionic neuroaxonal components. These tumours appear to represent a distinct type of gastric neoplasm originating from autonomic nerve elements in the stomach wall. They are different from previously described schwannomas or neurofibromas. In some of the tumours, identifiably neural elements are relatively a minor component, and the majority of the tumour cells are of undetermined origin. It is suggested that these cells may be poorly differentiated, lacking their antigenic determinants specific to neural differentiation.

Adult↗
PubMed1987

Regurgitant bile acids and mucosal injury of the gastric remnant after partial gastrectomy.

Three groups, each consisting of seven patients who had undergone either Billroth I, Billroth II, or pylorus-preserving gastrectomies, were evaluated more than 18 months postoperatively in terms of concentration and amount of bile acids in the gastric aspirate and histologic changes in the gastric remnant mucosa. Concentrations of bile acids were determined by gas chromatography and mucosal specimens were obtained by endoscopic biopsy. The total bile acid concentration and all of the individual fractional bile acid levels, whether free or conjugated, were significantly higher in the Billroth II group than in the other two groups. The amount of gastric aspirate was also highest in the Billroth II group. Endoscopic biopsy revealed glandular dysplasia to be predominantly in the Billroth II group. The presence of bile acids in the gastric remnant may contribute to mucosal injury, possibly leading to cancer in the gastric remnant, especially after the Billroth II operation.

Adult↗
PubMed1987

Comparison of selectivity of LDL removal by double filtration and dextran-sulfate cellulose column plasmapheresis, and changes of subfractionated plasma lipoproteins after plasmapheresis in heterozygous familial hypercholesterolemia.

The possibility of selective removal of low density lipoprotein (LDL) by double filtration (DF) and dextran-sulfate cellulose (DSC) column plasmapheresis in hypercholesterolemia and the acute recovery process of the subfractionated plasma lipoproteins after plasmapheresis in heterozygous familial hypercholesterolemia were investigated. Sixty-six percent of the LDL cholesterol and 42% of the HDL cholesterol were removed by 2.5 L DF plasmapheresis with the second filters having average pore diameters of 30 nm and 40 nm. Fifty-nine percent of the LDL cholesterol was removed by 2.5 L DSC column plasmapheresis, while HDL cholesterol did not change. Therefore, DSC column plasmapheresis could remove LDL much more specifically than DF plasmapheresis. VLDL increased rapidly and reached the preplasmapheresis level within four days after plasmapheresis. IDL returned to the preplasmapheresis level in 2 weeks. The LDL1 level was approximately 80% of the preplasmapheresis level on the 14th day. LDL2 reached the peak at the seventh day. HDL2 and HDL3 moved in the same manner and reached the peak on the seventh day after DF plasmapheresis.

Adult↗