Search PubMed⌕ Search

Biomedical subjects

N Kato

Publications and source records attributed to N Kato.

At least 613 records · Page 34Linked to original sources
PubMed1993

Event-related potentials in methamphetamine psychosis during an auditory discrimination task. A preliminary report.

Auditory event-related potentials (ERPs) during a syllable discrimination task were recorded from 15 patients suffering from methamphetamine (MAP) psychosis after the remission of acute psychotic symptoms, and from 15 normal age-matched controls. Subjects were instructed to press a button in response to the target syllables applied to one designated ear. In MAP psychotics, the attention-related negative components (Nd) area was reduced and P300 latency was delayed compared with normal controls. MAP psychotics and controls did not differ significantly in P300 amplitude. These findings suggest that MAP psychotics show some impairment in the auditory information processing.

Adult↗
PubMed1993

Long-term effects of alpha-interferon for treatment of chronic hepatitis C in terms of histological changes with aminotransferase normalization and hepatitis C virus RNA seroconversion.

To assess the effects of interferon treatment on chronic hepatitis C, histological changes long after treatment were compared with normalization of aminotransferases and seroconversion of hepatitis C virus RNA. Twenty one histologically proven chronic hepatitis C patients received alpha-interferon, 3 million units 3 times weekly for 12 months. Hepatitis C virus RNA was detected by reverse transcription/polymerase chain reaction method. Follow-up liver biopsies were performed 3 to 5 years after treatment. Fourteen of 21 (67%) patients showed normal aminotransferases for 3 to 5 years after treatment. HCV RNA seroconversion was observed in 12 of these patients. These responders showed improvement in histological activity indices and in histological findings. Two patients improved from chronic active hepatitis 2a to nonspecific changes, 1 from chronic active hepatitis 2a to portal fibrosis, 1 from chronic active hepatitis 2a to chronic persistent hepatitis and 1 from chronic active hepatitis 2b to chronic persistent hepatitis. Histological improvement of the liver correlated well with normalization of aminotransferases and seroconversion of hepatitis C virus RNA. These data indicate that complete histological resolution of chronic hepatitis C can be achieved by elimination of the virus with interferon treatment.

Alanine Transaminase↗
PubMed1993

Levels of somatostatin and cholecystokinin in the brain of ataxic mutant mice.

Changes in immunoreactive somatostatin (SOM) and cholecystokinin (CCK-8) levels in the cerebellum and cerebrum were investigated in three types of genetically-determined ataxic mutant mice: rolling mouse Nagoya (RMN), weaver, and Purkinje cell degeneration (PCD) mice. The cerebellar pathology in each of these types differs. The concentration of both SOM and CCK-8 (ng/mg weight) was significantly higher in the cerebellum and the cerebrum of the three types of ataxic mutant mice than in these regions in the respective controls. SOM and CCK-8 content (ng/organ) was significantly higher in PCD and RMN than in controls but this was not in the weaver mice. The possible involvement of both peptides in manifestations of ataxia is discussed.

Animals↗
PubMed1993

Structural analysis of HLA-B40 epitopes.

Two genes encoding HLA-B60 or HLA-B61 were cloned from Japanese and the exons of their genes were sequenced. One silent mutation was observed at the exon 1 between HLA-B60 (B*40012) and B*40011. Seven nucleotide substitutions were seen at the exon 3 between HLA-B61 (B*4006) and B*4002. Three substitutions at codon 95, CTC in B*4002 to TGG in B*4006, changed Leu in B*4002 to Trp in B*4006, while two substitutions at codon 97, AGC in B*4002 and ACG in B*4006, changed Ser in B*4002 to Thr in B*4006. Since B*4002 shares the epitope of alloantibodies specific for HLA-B61, two HLA-B61 subtypes are discriminated by two amino acid substitutions at residues 95 and 97. B*40012 and B*4006 differ by four amino acid substitutions on the beta sheet and five amino acid substitutions on the alpha 2 helix. Since the residues at the beta sheet seem hardly to affect the binding of alloantibody, it is suspected that the residues on the alpha 2 helix provide epitopes for alloantibodies that discriminate allospecificity between HLA-B60 and HLA-B61.

Amino Acid Sequence↗
PubMed1993

Genistein augments cyclic adenosine 3'5'-monophosphate(cAMP) accumulation and insulin release in MIN6 cells.

Effects of genistein on insulin release were studied using MIN6 cells, a glucose-sensitive insulinoma cell line. At the non-stimulatory concentrations of glucose, genistein did not affect insulin release, however, at the stimulatory concentrations of glucose, genistein significantly increased insulin release in a dose-dependent manner up to 20 micrograms/ml. The content of cAMP in MIN6 cells was also elevated significantly by genistein and the dose-response relationship between the genistein and cAMP accumulation was consistent with the relationship between the genistein and insulin release. These effects were inhibited by calcium antagonists or by the omission of extracellular calcium. Isobutylmethylxanthine (IBMX;0.1mM) increased both cAMP accumulation and insulin release in MIN6 cells and there were no additive effects by the addition of genistein. The accumulation of cAMP might have, at least in part, resulted from phosphodiesterase inhibition by genistein. These results suggest that genistein augments glucose-induced insulin release by the contribution of cAMP accumulation and calcium modulation which depends on extracellular calcium.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Susceptibility patterns and resistance to imipenem in the Bacteroides fragilis group species in Japan: a 4-year study.

A study was undertaken in Japan to evaluate the susceptibility patterns of Bacteroides fragilis group species (849 strains) isolated from December 1986 through May 1991. All of the strains, which included B. fragilis (610 strains), Bacteroides thetaiotaomicron (201 strains), and Bacteroides distasonis (38 strains), were studied for susceptibility to imipenem and 16 other antimicrobial agents by an agar dilution method. Metronidazole was the most active agent; the minimal concentration for 90% inhibition (MIC90) was 0.78 micrograms/mL, and no isolate was noted to be resistant to it during the entire study period. Amongst the beta-lactam agents tested, imipenem was the most effective antimicrobial drug; the rate of resistance to this agent was only 3.3%. Cefoperazone/sulbactam (MIC90, 6.25 micrograms/mL) and cephamycins (MIC90, 25-50 micrograms/mL) were found to be more active against B. fragilis strains, whereas minocycline (MIC90, 6.25 micrograms/mL) showed better activity against B. thetaiotaomicron and B. distasonis strains. Increasing resistance to imipenem was observed in B. fragilis (2.0%-5.9%) and B. thetaiotaomicron (2.5%-6.1%) during the 4-year study period. Detailed investigation of beta-lactamases from imipenem-resistant strains demonstrated that, amongst them, six of the B. fragilis strains for which the MICs of imipenem were > or = 25 micrograms/mL were producing imipenem-hydrolyzing metallo-beta-lactamase.

Bacteroides↗
PubMed1993

Detection of toxigenic Clostridium difficile in stool specimens by the polymerase chain reaction.

Polymerase chain reaction (PCR) amplification of a segment of the toxin A gene was used to detect toxigenic Clostridium difficile directly from stool specimens of patients with antibiotic-associated diarrhea. Although PCR-inhibitory substances were recognized in DNA prepared from stool specimens, the inhibitory substances were eliminated by using an ion-exchange column after phenol-chloroform extraction. Eventually, 39 stool specimens were evaluated by PCR. PCR results for detection of toxigenic C. difficile were in complete agreement with cell culture assay results; all 12 PCR-positive stool specimens were positive by cytotoxin assay, and all 27 PCR-negative specimens were negative by cytotoxin assay. Toxigenic C. difficile was cultured from all PCR-positive specimens. These results suggest that PCR amplification may be an effective method for laboratory diagnosis of C. difficile-associated diarrhea and colitis.

Bacterial Toxins↗
PubMed1993

Infundibulocystic basal cell carcinoma.

A case of infundibulocystic basal cell carcinoma is reported. The patient was a 56-year-old Japanese woman. Clinically, the cutaneous lesion was a 2 x 4-mm, dark reddish, well-demarcated papule on the left nasal bridge. Histologically, it showed findings typical of the disease criteria described by Walsh and Ackerman, i.e., it was a well-circumscribed, superficially located, basaloid cell tumor with multiple cysts containing cornified cells lined by infundibular epithelium. It showed no follicular bulbs and papillae, and the stroma was not highly fibrocytic, although clefts within the connective tissues and abundant mucin were observed. The tumor was diagnosed as an infundibulocystic basal cell carcinoma.

Basal Cell Carcinoma↗
PubMed1993

Plasticity of an aberrant geniculocortical pathway in neonatally lesioned cats.

Geniculocortical afferents to the lateral suprasylvian (LS) visual area come only from the C layers in normal adult cats. After neonatal lesions of areas 17 and 18, inputs to the LS area also arise from the A layers. We studied the plasticity of this aberrant pathway. We made lesions in areas 17 and 18 of newborn kittens, some of which were then monocularly deprived. In lesioned undeprived cats, retrograde tracing confirmed projections to the LS area from both the A and A1 as well as the C geniculate layers. In lesioned deprived cats, geniculate afferents from the A layers to the LS area came mainly from the layer receiving a normal visual input. We conclude that the development of the abnormal pathway from the A layers to the LS area is influenced by patterned visual activity.

Animals↗
PubMed1993

Necrotizing fasciitis appearing with petechiae as the first clinical sign.

A 64-year-old Japanese man with necrotizing fasciitis is reported. He developed an Enterobacter agglomerans infection in his left leg without any known causative surgery or trauma, although he had acute myelocytic leukemia as a predisposing condition. Uncommonly, the first clinical sign was petechiae. Surgical debridement could not be performed because of pancytopenia due to his original disease and chemotherapy. The patient died, and an autopsy was performed. Severe intravascular coagulation was observed in the cutaneous infected tissues, while little or no disseminated intravascular coagulation was observed in the major internal organs. The local microorganism factors such as necrotoxins were suspected to cause the intravascular coagulation in the infected tissues.

Fasciitis↗
PubMed1993

Isolated lichen planus of the nails treated with etretinate.

A 46-year-old Japanese man with isolated lichen planus of the nails is reported. The affected nails were all of the fingernails and the third and fourth toenails of both feet. Histologically, the ventral part of the proximal nail folds showed mild band-like cell infiltration below the epidermis, and the nail beds (ventral matrix) showed hypergranulosis and epidermal-dermal interphase activity with liquefaction degeneration of basal cells and a band-like cell infiltration consisting of lymphoid cells and histiocytes. Systemic use of etretinate in combination with application of steroid lotion was evaluated as very effective. Although the use of retinoids for lichen planus of the nails remains only a suggested method of treatment, a positive trial should be attempted, since this disorder sometimes results in severe nail damage.

Etretinate↗
PubMed1993

Human papillomavirus type 6 associated Buschke-Loewenstein tumor (giant condyloma acuminatum).

The term "Buschke-Loewenstein tumor" has been used for tumors with exophytic, wart-like excrescences in the anogenital region. This broadly includes giant condyloma acuminatum and verrucous carcinoma. We report a 44-year-old Japanese man with a giant condyloma acuminatum Buschke-Loewenstein tumor on the right femoinguinal area. The lesion was a huge grape-like nodule composed of multiple small nodules, reaching 135 x 65 x 40 mm in size. Histologically, it showed a regularly acanthotic papilloma with numerous koilocytes in the upper squamous and granular layers. Ultrastructural findings included gradual differentiation from basal cell layers to uppermost corneocytes without disorganized relationships in the epithelial-stromal junction or cellular atypia. Human papillomavirus type 6 DNA was detected in the tumor tissues by polymerase chain reaction and restriction enzyme analysis, although immunohistochemical staining for papillomavirus common antigen was negative.

Adult↗
PubMed1993

Eosinophilic panniculitis.

A 39-year-old obese female patient with borderline diabetes mellitus who developed multiple, tender, and hard nodules on the lower abdominal wall is described. The histological features were characterized by mixed panniculitis, showing massive eosinophilic infiltration and fibrosis in the septae and many foam cells in the parenchymal area of subcutaneous tissues. The eruption regressed gradually during the course of diet therapy for diabetes mellitus and obesity. Although the etiology is diverse and nonspecific, eosinophilic panniculitis seems to be a unique histopathological reaction pattern characterized by massive eosinophilic infiltration into subcutaneous tissues.

Abdominal Muscles↗
PubMed1993

Polymorphism of crystals of Salmonella minnesota Re and Ra lipopolysaccharides.

Salmonella minnesota Re and Ra lipopolysaccharides (LPSs) formed three-dimensional crystals when they were precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and incubated in 70% ethanol containing 250 mM MgCl2 at 4 C. Besides typical shapes of crystals, hexagonal plates and solid columns, which were already reported (J. Bacteriol. 172: 1516-1528 (1990)), the LPSs thus treated formed crystals possessing various shapes such as square or rectangular plate, lozenge plate, discoid, and truncated hexangular pyramid forms. Electron diffraction patterns from all these crystals except square or rectangular plate crystals obtained by electron irradiation from the direction perpendicular to the basal plane were essentially the same as those from hexagonal plate crystals, indicating that they consist of hexagonal lattices with the lattice constant of 4.62 A. From these results as well as the results of electron microscopic observations of these crystals, it was concluded that all these crystals except square or rectangular plate crystals are composed of hexagonal plate sheets as the basic structural units. Square or rectangular crystals were assumed to correspond to the (1011) planes of solid hexagonal column crystals.

Crystallography↗
PubMed1993

Isolation of rfb gene clusters directing the synthesis of O polysaccharides consisting of mannose homopolymers and serological analysis of lipopolysaccharides.

Four serotypes of two genera, Escherichia coli O8 and O9 and Klebsiella O3 and O5, produce the O polysaccharides consisting of mannose homopolymers. Previously, we reported the isolation and expression of E. coli O9 rfb in E. coli K-12 strains (Kido et al, J. Bacteriol., 171: 3629-3633, 1989). In this study, R' plasmids carrying his-rfb region of the other three strains were isolated and expressed in E. coli K-12 strain. Serological study of lipopolysaccharides (LPS) synthesized in E. coli K-12 strain was carried out. His-linked rfb genes from E. coli O9 and Klebsiella O3 directed the synthesis of O polysaccharides with the same antigenicity as those of the parental strains in E. coli K-12 strain. On the other hand, rfb genes from E. coli O8 and Klebsiella O5 directed the synthesis of O polysaccharides which were antigenically not identical but partially common to those of the parental strains. A rough strain derived from E. coli O8 synthesized LPS which showed the identical antigenicity as the wild strain when the his-rfb region of E. coli O8 was introduced. The results suggest that some genes located distantly from his are additionally required to complete the synthesis of O polysaccharides of E. coli O8 and Klebsiella O5.

Carbohydrate Conformation↗