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Biomedical subjects

M Kato

Publications and source records attributed to M Kato.

At least 721 records · Page 40Linked to original sources
PubMed1998

Detection of coccoid Helicobacter pylori: light microscopical immunogold silver enhancing stain.

BACKGROUND: Helicobacter pylori (H. pylori) can be morphologically divided into spiral and coccoid forms. Although many different staining procedures for light microscopy have been developed to detect H. pylori, there are no reports that the coccoid forms can be specially identified by a staining method. The ability to identify the coccoid form of H. pylori by light microscopy would be important for studies evaluating its possible role in gastric disease. We examined whether both the coccoid and the spiral forms could be stained using anti-H. pylori antibody. METHODS: Specimens from the stomachs of dyspeptic patients with proven H. pylori infection and H. pylori from culture (1st and 4th day) were stained with the light microscopic immunogold silver enhancing stain using the rabbit IgG specific for H. pylori. Cultured H. pylori was also stained with electron microscopic immunogold staining method using the same antibody. The number of coccoid forms was counted by scanning electron microscopy. RESULTS: Biopsies and H. pylori from 6 patients were studied. H. pylori from both biopsy material and culture appeared as black organisms by light microscopic immunogold silver enhancing stain. The coccoid forms constituted 0.4% and 98.3% on days 1 and 4 of culture, respectively (by scanning electron microscopy). The antigen recognized by the anti-H. pylori antibody was located on the surface of the flagella, the cell wall, or in the cytoplasm by immunoelectron microscopy. CONCLUSION: This study shows that both spiral and coccoid forms of H. pylori can be detected by light microscopic immunogold silver enhancing stain using anti-H. pylori antibody. This simple stain is to be proven useful for studies aimed at understanding whether the coccoid form plays a role in disease.

Animals↗
PubMed1998

[Reevaluation and potential therapeutic effects of estrogen therapy to prostate cancer patients].

Survival time of 65 patients with stage D2 prostate cancer who were treated by estrogen with or without antiplatelet drugs was examined. Survival time of 37 patients with antiplatelet drugs was significantly longer than that of 28 histological control ones. The frequency of death of cardiovascular disease in the former group decreased to 5.3%. Next, progression free time of the 37 patients was compared to the time of 37 patients treated by antiandrogen therapy. The former one was better than the latter. However, survival time after relapse of the estrogen group was shorter than the control. These results suggest that estrogen therapy improved by a combination of antiplatelet drugs has to be reevaluated and contains specific therapeutic effects differing from antiandrogen therapy.

Antineoplastic Agents, Hormonal↗
PubMed1998

Effects of rebamipide in combination with lansoprazole and amoxicillin on Helicobacter pylori-infected gastric ulcer patients.

The aim of this study was to compare the additive effect of rebamipide with that of teprenone in combination with dual therapy on H. pylori eradication. A total of 102 H. pylori-positive gastric ulcer patients were assigned at random to two groups; in addition to dual therapy (amoxicillin 500 mg thrice daily and lansoprazole 30 mg every morning for two weeks), one group received rebamipide 100 mg thrice daily for eight weeks, while the other group received teprenone 50 mg thrice daily for eight weeks. H. pylori diagnosis after treatment was made by [13C]UBT. The ulcer healing rate was 85.7% in the rebamipide group and 79.5% in the teprenone group (P = NS). The eradication rate was 68.4% (95% CI = 54-83%) in the rebamipide group and 47.7% (95% CI = 32-61%) in the teprenone group (P = 0.043) by per-protocol analysis. These findings suggest that the efficacy of dual therapy may be increased by the administration of rebamipide.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

Clinical studies of 13C-urea breath test in Japan.

The urea breath test (UBT) using isotope carbon is a non-invasive method for diagnosing H. pylori infection. In Japan, only 13C-UBT using a stable isotope is available, since the clinical use of radioactive isotope 14C-compounds is prohibited. Since there is no worldwide standard protocol for the 13C-UBT, it is therefore important to standardize this test to obtain a cheap, easy, reproducible method. Factors affecting the outcome of 13C-UBT values include sampling times and frequency, the amount of 13C-urea, the cut-off value, the avoidance of oral urease activity, and changes in gastric emptying times and 13C-urea distribution. Mouth rinsing reduces false-positive results due to oral urease activity, particularly within 20 min after ingestion of 13C-urea. A Japanese multicenter trial has shown that the diagnostic utility of 13C-UBT is superb, with the cut-off value 2.5/1000 in 20-min samples after ingestion of 100 mg 13C-urea. The 13C-UBT is a very useful method for diagnosing H. pylori infection.

Breath Tests↗
PubMed1998

Ten minute 13C-urea breath test for the diagnosis of Helicobacter pylori infection.

We investigated the utility of a 10-min 13C-urea breath test (13C-UBT) using 100mg of 13C-urea; this is a simple and rapid method for the detection of Helicobacter pylori infection. One hundred and fifty-one patients in whom the identification of H. pylori was established by rapid urease test, culture, and histology of six biopsy specimens underwent 254 13C-UBT examinations before and/or after eradication treatment. In the 133 patients who did not receive eradication treatment, the calculated sensitivity of the 10-min 13C-UBT was 99.4% and specificity 100% when the cut-off point was set at 3.5/1000, using a mass spectrometer. In the 121 patients who received eradication treatment, this cut-off point gave a sensitivity of 86.7%, a specificity of 99.1%, and a positive predictive value of 92.9%, with a negative predictive value of 98.1%. There were no significant differences between the diagnosis of H. pylori infection at 1 month and more than 3 months after the endpoint of eradication treatment. The 10-min 13C-UBT is suitable for the diagnosis of H. pylori infection before and after eradication treatment.

Breath Tests↗
PubMed1998

[Tuberculous lymphadenitis].

Tuberculous lymphadenitis is a common extrapulmonary tuberculosis. Its incidence is about 28%. Pulmonary hilar lymphadenitis and mediastinal lymphadenitis are often visible in the routine chest X-ray films during pulmonary tuberculosis. But abdominal lymphadenitis are difficult to detect on this method. Computed tomography is a useful tool to detect the tuberculous lymphadenitis both mediastinal and abdominal. The active tuberculous lymphadenitis shows characteristic findings with contrast enhanced CT, central low attenuation and peripheral rim enhancement were seen. On the contrary homogeneous without low attenuation area and with calcification were inactive tuberculosis. Bacterial diagnosis is difficult and PCR method is effective for detect the tuberculosis. Usual anti-tuberculous chemotherapy were performed for the tuberculous lymphadenitis and effective but on the fistula formation surgical procedure are also performed.

Humans↗
PubMed1998

[Outpatient chemotherapy with weekly high-dose infusional 5-fluorouracil (weekly HD-FU) in advanced gastrointestinal cancer].

This study was designed to evaluate the efficacy, toxicity, and quality of life (QOL) of outpatient chemotherapy with weekly HD-FU in advanced gastrointestinal cancer. Treatment consisted of weekly 24-h infusion of 5-FU 2,600 mg/m2, 5-FU was administered using the Groshong catheter and the Baxter infusor LV 5 (5 ml/hr). Eight patients (pts) with advanced gastrointestinal cancer were treated 64 times (mean 8.0 times), and 21 pts were treated 168 times (mean 8.0 times) with adjuvant chemotherapy. Grade 3 or 4 toxicities were not observed. Catheter occlusions and balloon rupture were observed in 1 case each. Responses were PR 2 and NC 6. Mean times to progression were 2.0 and 3.5 months, respectively. Mean scores of QOL were: 70.5 +/- 8.2 before treatment, 78.0 +/- 13.0 after 3 weeks, 79.8 +/- 7.9 after 5 weeks, and 75.8 +/- 11.3 after treatment completion. In adjuvant cases, these scores were 80.6 +/- 11.4, 83.1 +/- 10.7, 85.1 +/- 11.5, and 91.8 +/- 6.9, respectively. In conclusion, a schedule of 5-FU is feasible for outpatient chemotherapy in advanced gastrointestinal cancer.

Adult↗
PubMed1998

[A case of early-onset cortical cerebellar atrophy with rhythmic skeletal myoclonus in the left upper limb].

A 19-year-old man developed progressive unsteady gait and speech disturbance two years ago. He recently noticed muscle twitches in the left limb. Neurological examination revealed scanning speech, saccadic ocular movement, ataxia of trunk and limbs predominant on the left side. Rhythmic myoclonus was present at rest around the left shoulder and arm, and amplified by raising the left arm. There was no myoclonus in the soft palate. MRI revealed only a cerebellar atrophy. This patient was diagnosed as having cortical cerebellar atrophy with rhythmic skeletal myoclonus (RSM). Tc-99m ECD SPECT showed a decrease in the blood flow of the right thalamus when the myoclonus was enhanced by raising the left upper limb, which suggests that the cerebello-thalamo-cortical system as well as Guillain-McIlaret triangle is involved in the development of RSM.

Adult↗
PubMed1997

An assessment of antigenic potential of beta-lactam antibiotics, low molecular weight drugs, using guinea pig models.

Allergic reactions are among the common adverse effects in humans. However, it is widely assumed that there are practically no reliable animal models for preclinical tests of low-molecular weight drugs that are available to predict such reactions. This study was designed to compare the detecting ability of test methods for antigenic potential of eight beta-lactam antibiotics with which allergic outcome has been reported in humans. The tests included active systemic anaphylaxis (ASA), delayed type skin reaction (DSR), maximization test (GPMT) in guinea pigs sensitized with antibiotics emulsified with Freund's complete adjuvant, passive cutaneous anaphylaxis (PCA) and enzyme-linked immunosorbent assay (ELISA) as serological tests. PCA and ELISA though using protein-conjugates as detecting antigens, especially ELISA, showed positive reactions with relatively high incidence. On the other hand, GPMT was the most sensitive method to detect antigenic potential of antibiotics despite the use of antibiotics alone for sensitizing and challenging phases. It is suggested that GPMT can be considered the most reliable method in preclinical testing.

Anaphylaxis↗
PubMed1997

Coronary segmental responses to acetylcholine and bradykinin in patients with atherosclerotic risk factors.

This study was designed to elucidate the nature of coronary endothelial dysfunction in patients with hypertension and/or hypercholesterolemia and normal smooth coronary arteries by evaluating the coronary vascular responses to acetylcholine and bradykinin. The study included 19 patients (10 men; age [mean +/- SD] 61 +/- 9 years) with angiographically normal smooth coronary arteries and either hypertension (n = 7) and/or hypercholesterolemia (n = 13). Patients received acetylcholine (3 or 30 microg/min) infusions followed by bradykinin (0.5, 1.5, 2.5 microg/min) and nitroglycerin (200 microg/min) infusions into the left coronary ostium. Epicardial coronary artery diameters were measured by quantitative angiography. Angiography detected both vasoconstricted and dilated segments following acetylcholine infusion. Bradykinin significantly dilated both types of segments (p <0.001, respectively). However, bradykinin-induced dilation was significantly greater in segments exhibiting acetylcholine-induced vasodilation than in those exhibiting vasoconstriction (p <0.01 in the proximal portion and p <0.02 in the distal portion). Nitroglycerin-induced dilation was similar in all segments. These results suggest that coronary endothelial dysfunction may be a heterogeneous process in patients with coronary risk factors. Moreover, the mechanism underlying diminished endothelium-dependent dilation involves not only the muscarinic receptor, but also B2-kinin receptor.

Acetylcholine↗
PubMed1997

Protein kinase C alpha-mediated chronic signal transduction for immunosenescence.

In CD2/protein kinase C alpha (PKC alpha)-overexpressing human CD2/rabbit PKC alpha transgenic mice, an aging-dependent increase in PKC alpha expression and a decrease in proliferative responsiveness of splenic T cells were promoted. We found that an aging-associated accumulation of CD44(high) CD45RB(low) memory CD4+ T cells in exchange for CD44(low) CD45RB(high) naive CD4+ T cells was promoted in transgenic mice. A disequilibrium between Ag-dependent generation and subsequent elimination of memory T cells in these mice was shown to underlie this phenomenon. When stimulated with Ag, the PKC alpha transgenic mice responded poorly regarding Ab production and produced cytokines biased for high IFN-gamma/IL-12 and low IL-4/IL-10 levels. These results prove, for the first time, a causal role for chronic signal transduction through PKC alpha in aging-associated immunodysfunction and provide the first animal model for genetically promoted immunosenescence.

Aging↗
PubMed1997

Novel biological response modifiers: phthalimides with tumor necrosis factor-alpha production-regulating activity.

Novel N-substituted phthalimides (2-substituted 1H-isoindole-1,3-diones) were prepared, and their effects on tumor necrosis factor-alpha (TNF-alpha) production by human leukemia cell line HL-60 stimulated with 12-O-tetradecanoylphorbol 13-acetate (TPA) or okadaic acid (OA) were examined. A structure-activity relationship study of the N-phenylphthalimides and N-benzylphthalimides revealed that their enhancing effect on TPA-induced TNF-alpha production by HL-60 cells and their inhibiting effect on OA-induced TNF-alpha production by HL-60 cells are only partially correlated.

Cell Survival↗
PubMed1997

Growth/differentiation factor-5 induces angiogenesis in vivo.

Bone morphogenetic proteins (BMPs) are multifunctional cytokines, which induce bone and cartilage formation and exert various other effects on many tissues. Since angiogenesis is involved in the bone formation process, certain members in the BMP family may induce angiogenesis. We examined the in vivo angiogenic activity of BMP family members, i.e., growth/differentiation factor (GDF)-5 and BMP-2. GDF-5 induced angiogenesis in both chick chorioallantoic membrane and rabbit cornea assays. In contrast, BMP-2 did not induce angiogenesis. In order to elucidate the mechanism of angiogenesis, we examined the effects of GDF-5 on cultured bovine aortic endothelial cells (BECs). GDF-5 induced plasminogen activator activity and accelerated the migration of BECs in a chemotactic fashion, which may contribute to the process of angiogenesis in vivo. These results suggest that GDF-5 is one of the molecules which induce angiogenesis in the bone formation process.

Allantois↗
PubMed1997

Ki-67 labeling indices in non-small cell lung cancer: comparison between image cytometry and flow cytometry.

Expression of the proliferation-associated nuclear antigen Ki-67 was studied in 27 human non-small cell lung cancers (NSCLCs). We measured immunohistochemical Ki-67 labeling indices using image cytometry (ICM) and flow cytometry (FCM) and compared the indices determined with the two methods. Ki-67 labeling indices of tumor cells ranged from 2% to 59% with ICM, and from 3% to 56% with FCM, varying from case to case. There was a linear correlation of values between the two methods (r = 0.77, P < 0.05). To examine whether Ki-67 labeling indices represent tumor proliferative activity, we studied the relationship between the Ki-67 labeling index and the S-phase fraction determined by FCM. There was a positive correlation between the Ki-67 labeling index and the S-phase fraction (r = 0.91, P < 0.01). Comparison of Ki-67 labeling indices and clinicopathological parameters showed lower Ki-67 labeling indices in well-differentiated tumors than in moderate and poorly differentiated tumors (P < 0.05). No correlation was observed between Ki-67 labeling indices and p53 expression. It was concluded that the Ki-67 labeling index was in fact measured with both ICM and FCM, and that it represents tumor proliferative activity of NSCLCs.

Adenocarcinoma↗
PubMed1997

Cell density-dependent apoptosis in HL-60 cells, which is mediated by an unknown soluble factor, is inhibited by transforming growth factor beta1 and overexpression of Bcl-2.

We report a novel mode of apoptosis induction observed in human leukemic HL-60 cells. These cells spontaneously underwent apoptosis in the course of proliferation when the cell density became higher than 1 x 10(6)/ml. This occurred under ordinary in vitro culture conditions, with or without fetal calf serum. Even the low density cells were committed to undergo apoptosis if they were cultured under artificially concentrated conditions. Replacement of the culture supernatant of the low density cells by that of the high density ones resulted in apoptosis induction in the former cells. This apoptosis-inducing activity of the high density cell culture supernatant was completely eliminated by the action of trypsin but was fully restored following ultrafiltration by 3-kDa pore-sized membrane. A strong apoptosis-inducing activity was recovered from the culture supernatant of the high density HL-60 cells at a specific fraction in reverse-phase column chromatography. Neither an interleukin-beta converting enzyme inhibitor nor CPP-32 inhibitor blocked the induction of cell density-dependent apoptosis in HL-60 cells, although overexpression of Bcl-2 protein markedly attenuated the induction of this mode. Surprisingly, transforming growth factor-beta1 and activin A did not induce but, rather, inhibited the induction of cell density-dependent apoptosis. These data suggest that HL-60 cells release an unknown low molecular weight peptide-containing factor in response to an increase in cell density to induce apoptosis in an autocrine manner and that the interleukin-beta converting enzyme-independent intracellular machinery for this mode of apoptosis is strongly affected by signaling events through the transforming growth factor-beta1 receptor and by the action of Bcl-2 oncoprotein.

Activins↗
PubMed1997

Histidine-44 of the A subunit of Escherichia coli enterotoxin is involved in its enzymatic and biological activities.

We examined the role in toxicity of histidine-44 of the A subunit of Escherichia coli enterotoxin, which is located in the active site cavity close to glutamic acid-112. Although amino acid substitution of histidine-44 usually renders a mutant toxin unstable to trypsin, one mutant, alanine-44 (His44Ala) was found to be stable. His44Ala did not show any agmatine:ADP-ribosyltransferase activity in the presence or absence of recombinant ADP-ribosylation factor. It showed no diarrheal or rabbit skin permeability activity and was a competitor in enterotoxin-ADP-ribosyltransferase assays containing recombinant ADP-ribosylation factor. These results suggest that like glutamic acid-112, histidine-44 plays an essential role in toxicity. A tentative model, which explains NAD+ catalysis and the transfer of the ADP-ribosyl moiety to a target amino acid, is proposed for histidine-44 and glutamic acid-112.

ADP-Ribosylation Factors↗
PubMed1997

Human amylin mimics amyloid beta protein-induced reactive gliosis and inhibition of cellular redox activity in cultured astrocytes.

We have previously found that Alzheimer's disease amyloid beta protein (A beta) induces reactive gliosis and inhibits cellular redox activity of astrocytes. In the present study, human amylin, an amyloidogenic peptide with primary sequence dissimilar to A beta, mimicked the effects of A beta in cultured astrocytes. However, the non-amyloidogenic rat amylin showed no effect. These results suggest that amyloidogenic property is important for A beta to induce morphological and functional changes of astrocytes.

Amyloid↗