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Biomedical subjects

K Katsu

Publications and source records attributed to K Katsu.

88 records · Page 5Linked to original sources

In vitro antibacterial activity of E-0702, a new semisynthetic cephalosporin.

E-0702 is an antipseudomonal cephalosporin derivative which has a broad spectrum of antibacterial activity against clinical isolates of gram-positive and gram-negative bacteria. Its in vitro antibacterial activities were less than those of cefoperazone and cefotaxime against Staphylococcus aureus and Staphylococcus epidermidis, but were significantly high against gram-negative bacteria including the Pseudomonas group. It was most characteristic that E-0702 showed high antibacterial activity against Pseudomonas aeruginosa. E-0702 was relatively stable to inactivation by plasmid-mediated penicillinases and cephalosporinases produced by gram-negative bacteria.

Anti-Bacterial Agents↗

Transposition of the carbenicillin-hydrolyzing beta-lactamase gene.

We isolated a new transposon Tn2101, from plasmid Rms433 in Enterobacter cloacae. Tn2101 encoded the formation of type IV (carbenicillin-hydrolyzing) beta-lactamase and multiple resistance to streptomycin, sulfanilamide, spectinomycin, and mercury in addition to ampicillin. Tn2101 was transposable between conjugative (or nonconjugative) plasmids and the host chromosome. Transposition occurred independently of the general recombination ability of the host cell. Tn2101 had a molecular size of 9.5 x 10(6) and contained short inverted repeat terminal sequences.

Anti-Bacterial Agents↗

Comparison of gastric mucosal surface pH response times after intravenous administration of histamine2-receptor antagonists.

Gastric mucosal surface pH was measured endoscopically in patients with peptic ulcer, erosive gastritis, or nonulcer dyspepsia following intravenous administration of either 200-mg cimetidine, 50-mg ranitidine, or 40-mg famotidine. The mean baseline pH in the three treatment groups before drug administration ranged from 0.85 to 0.99, with no significant difference between groups. Following treatment with cimetidine, ranitidine, and famotidine, the mean response times for the mucosal surface pH values to increase to 3.5 were 10.1 +/- 5.9 minutes, 11.2 +/- 6.8 minutes, and 17.3 +/- 6.7 minutes, respectively. The corresponding response times to reach pH levels of 6.0 were 16.0 +/- 9.4 minutes, 17.0 +/- 5.4 minutes, and 31.2 +/- 21.7 minutes, respectively. The response times to pH levels of 3.5 and 6.0 were significantly faster in patients who received cimetidine compared with patients who received famotidine (P = 0.0088 to pH 3.5 and P = 0.046 to pH 6.0). The differences between cimetidine and ranitidine were not significant. These findings suggest that at recommended clinical doses, intravenous cimetidine provides rapid elevation of the gastric mucosal surface pH compared with other histamine2-receptor antagonists. This finding may be particularly relevant in the emergency care of patients with severe peptic ulcer disease (eg, patients with gastrointestinal hemorrhage).

Adult↗

Effect of upper gastrointestinal endoscopy on circulation in the elderly.

BACKGROUND: Upper gastrointestinal endoscopy in the elderly is increasingly becoming more common, despite the possibility that a minimal load on the circulation can cause serious complications such as shock and cardiac arrest. OBJECTIVE: The effects of endoscopy on the heart and the possibility of predicting circulatory accidents were studied using natriuretic peptide levels. METHODS: The patients were randomly chosen according to their age and divided into an elderly group (over 60 years of age, 64 patients) and a young group (under 30 years of age, 20 patients). The patients in the elderly group were further subdivided into two groups based on the presence or absence of circulatory complications (46 patients with circulatory complications and 18 without complications). The load on the heart was evaluated by measuring human atrial natriuretic peptide (hANP) and human brain natriuretic peptide (hBNP) which are secreted by the myocardial cells in response to cardiac load. Specimens were obtained before and after endoscopy. RESULTS: The hANP level was significantly higher after endoscopy in the elderly group, regardless of the presence or absence of circulatory complications. No significant difference was observed in the hBNP level. No significant increase in hANP or hBNP levels was observed after endoscopy in the young group. CONCLUSIONS: These observations suggest an increased atrial load during endoscopy in the elderly. The increase in pulse rate during endoscopy is one possible cause of atrial load. Therefore, the risk of circulatory system damage must be recognized when endoscopy is performed in the elderly. The measurement of plasma hANP and hBNP levels may provide effective indices for evaluating cardiac load during endoscopy.

Adult↗

[The effects of upper gastrointestinal endoscopy on the circulatory system of elderly patients as evaluated by measuring hANP and hBNP].

Endoscopic examinations of the elderly have been increasing annually due to increase in the size of the elderly population, and due to the development and increased use of upper gastrointestinal endoscopy. The reserve potential of the circulatory system is frequently diminished in the elderly. Thus, a minimal load on the circulatory system can induce a critical status. Therefore, the effects of endoscopic examination on the circulation, most notably on the heart itself, was examined in the elderly (over 60 years old) and in younger (under 30 years old) individuals. Atrial and ventricular load were evaluated by measuring the concentration of human atrial natriuretic peptide (hANP) and human brain natriuretic peptide (hBNP), both before and after endoscopic examination. These peptides are secreted by myocardial cells in reaction to sharp increases in cardiac load. No significant difference was observed between the blood pressure of the elderly group (21 cases) and that of the young group (10 cases), either before or after endoscopic examination. However, the pulse rate was raised significantly after the examination in both groups. Furthermore, the hANP concentration was significantly higher after the endoscopic examination in the elderly group, although no notable difference in hBNP concentration was observed after endoscopy. In the younger group, the hANP concentration did not change significantly, but the hBNP concentration was notably lower after the examination. Increased atrial load during endoscopic examination of the elderly was indicated by these observations. Therefore, overall patients status must be correctly evaluated, with particular recognition of potential circulatory system damage, when endoscopic examinations are performed on the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Immunohistochemical expression of vascular endothelial growth factor can predict response to 5-fluorouracil and cisplatin in patients with gastric adenocarcinoma.

The combination of 5-fluorouracil (5-FU) and cisplatin is used most commonly for gastric carcinoma. Recent studies have indicated that vascular endothelial growth factor (VEGF) is related to drug delivery through angiogenesis and vascular permeability. In this study, we evaluated the efficacy and toxicity of continuous infusion of 5-FU and low dose cisplatin infusion as first-line treatment in patients with unresectable gastric adenocarcinoma. We also examined the relationship between chemotherapy response and immunohistochemical expression of VEGF in the biopsy samples of gastric primary. All 30 patients enrolled in this study were assessable for response, adverse reactions, and VEGF expression. The regimen consisted of 5-FU (350 mg/m2/day every day by continuous venous infusion) and low dose cisplatin (7 mg/m2/day by drip infusion over 1 h on days 1-5 every week). This treatment was repeated weekly for 3 consecutive weeks. Four weeks after the second cycle, mesurable lesions were estimated for response. An overall response rate was 46.7% (14/30). Patients with intestinal histologic type (10/12) and good performance status ([PS], 13/18) showed good response rate (83.3%, and 72.2%, respectively) compared to patients with diffuse histologic type (4/18) and poor PS [(1/12) 22.2%, and 8. 3%, respectively]. The response rate of VEGF-positive cases and VEGF-negative cases was 75% (12/16), and 16.7% (2/14), respectively. Multivarite analysis revealed that VEGF-positive and good PS had a significant impact on chemotherapy response in this treatment. The most common garde 3 or higher toxicities were myelosuppression (30%) and diarrhea (13.3%). Continuous infusion of 5-FU and low dose cisplatin infusion is an effective treatment for patients with unresectable gastric carcinoma, and VEGF expression may be a useful predictor of chemotherapy response in this regimen.

Adenocarcinoma↗

Breath and blood ammonia in liver cirrhosis.

BACKGROUND/AIMS: Hyperammonemia causes dysfunction of multiple organs in patients with cirrhosis, including hepatic encephalopathy. Blood ammonia concentrations are monitored with respect to disease progression and efficacy of treatment. Fetor hepaticus, the characteristic breath odor in hepatic encephalopathy has called little quantitative attention to breath ammonia. We studied the dynamics of ammonia metabolism in cirrhosis in terms of the relationship between breath and blood ammonia. METHODOLOGY: Breath and blood ammonia levels were measured simultaneously in 20 cirrhotic patients and in 10 healthy volunteers. Breath ammonia was measured using ammonia electrodes in collected expired air. Helicobacter pylori serum antibody titers were also measured, since the organism produces ammonia. RESULTS: Blood ammonia correlated positively with breath ammonia in patients with cirrhosis. Breath ammonia levels were significantly higher in cirrhotic patients (0.745 ppm) than in controls (0.278 ppm), and higher in cirrhotic patients with hyperammonemia (0.997 ppm) than in those without (0.558 ppm). Breath and blood ammonia decreased together with treatment of hyperammonemia. H. pylori seropositivity was 20% in controls, 27.3% in cirrhotic patients with normal blood ammonia, and 66.7% in those with hyperammonemia. CONCLUSIONS: Breath ammonia measurement may be useful in diagnosis, treatment assessment, and follow-up in hepatic encephalopathy.

Adult↗