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S Mizobuchi

Publications and source records attributed to S Mizobuchi.

33 records · Page 2Linked to original sources
PubMed1994

Comparison of the virulence of methicillin-resistant and methicillin-sensitive Staphylococcus aureus.

The virulence of methicillin-resistant Staphylococcus aureus (MRSA) was compared with that of methicillin-sensitive S. aureus (MSSA), using 13 MRSA and 7 MSSA strains isolated from clinical specimens. The infectivity and lethality of the two groups were examined as to the inoculum required to infect 50% of guinea pigs (ID50) and to kill 50% of mice (LD50), respectively. The mean ID50 [log10 colony forming units (CFU)] for MRSA strains was 7.1 +/- 0.60 standard deviation, which was 1.5 higher than that for MSSA strains (P < 0.001). The mean LD50 (log10 CFU) for MRSA strains was 9.0 +/- 0.42, being 1.1 higher than that for MSSA strains (P = 0.001). Pretreatment of mice with cyclophosphamide decreased the mean LD50 for MRSA strains more than that for MSSA strains, resulting in the difference in the mean LD50 being insignificant (P = 0.502). These results indicate that MRSA is less virulent than MSSA in normal hosts, but that they are equally virulent in immunocompromised hosts. The growth of MRSA strains was much slower than that of MSSA strains in the lag phase, although their growth rates were almost the same in the exponential growth phase, suggesting that the difference in virulence between them may be at least partly due to such a difference in growth.

Animals↗
PubMed1994

Growth requirements of hyperthermophilic sulfur-dependent heterotrophic archaea isolated from a shallow submarine geothermal system with reference to their essential amino acids.

Three hyperthermophilic sulfur-dependent heterotrophs were isolated from a shallow submarine hydrothermal system at an inlet of Kodakara-jima island, Kagoshima, Japan. The isolates grew at 60 to 97 degrees C, with the optimum temperatures at 85 to 90 degrees C. Sensitivity to rifampin and the existence of ether lipids indicated that the isolates are hyperthermophilic archaea. Partial sequencing of the genes coding for 16S rRNA showed that the three isolates are closely related to the genus Thermococcus. They grew on proteinaceous mixtures, such as yeast extract, Casamino Acids, and purified proteins (e.g., casein and gelatin), but not on carbohydrates or organic acids as sole carbon and energy sources. Nine amino acids were essential for growth of isolate KS-1 (Thr, Leu, Ile, Val, Met, Phe, His, Tyr, and Arg). Isolate KS-2 required Lys in addition to the nine amino acids, and KS-8 required Lys instead of Tyr. In comparative studies, it was shown that Thermococcus celer DSM 2476 required 10 amino acids (Thr, Leu, Ile, Val, Met, Phe, Tyr, Trp, Lys, and Arg) while Pyrococcus furiosus DSM 3638 required only Ile and Val. The hyperthermophilic fermentative eubacterium Thermotoga neapolitana DSM 4359 did not require any amino acids for growth.

Amino Acids, Essential↗
PubMed1993

Cervical, mediastinal, and abdominal lymph node dissection (three-field dissection) for superficial carcinoma of the thoracic esophagus.

BACKGROUND: The recent increase in the number of esophageal carcinomas detected at an early stage has prompted debate about the most suitable treatment for them. METHODS: Forty-three patients with superficial esophageal carcinoma (SEC) underwent esophagectomy with cervical, mediastinal, and abdominal lymph node dissection (three-field dissection). On the basis of the pathologic data and results of surgery, the adequacy of treatment was discussed. RESULTS: Three patients with pTis tumor had no positive lymph nodes. Twenty patients (46.5%) had positive nodes in the resected specimen. Nineteen lesions (57.6% of submucosal cancers) with lymph node metastasis had invasion to the submucosa. Five patients with submucosal cancer (15.2% of submucosal cancers) had positive nodes in the neck. The lymph nodes along the right recurrent nerve and the right paracardiac nodes were the most frequent site of metastasis (16.3%), whereas the right paratracheal, infracarinal, infra-aortic arch, common hepatic, and celiac nodes had no metastasis. The operative mortality rate was 2.3%. Recurrent disease occurred in three patients with submucosal cancer. The 5-year survival rate after surgery was 73.2% for all 43 patients and 68.6% for patients with positive nodes. CONCLUSIONS: Esophagectomy with three-field lymph node dissection is recommended for patients with lesions diagnosed as submucosal cancer. Endoscopic mucosectomy is applicable as a first-choice treatment for patients with esophageal carcinoma at Tis.

Abdomen↗
PubMed1993

Multiple primary carcinoma of the oesophagus.

A retrospective evaluation of 239 patients with primary oesophageal carcinoma who underwent oesophagectomy without preoperative treatment revealed 45 cases (18.8%) of multiple primary oesophageal carcinoma (MPEC). The average age of the patients with MPEC was significantly lower than that of patients with single primary oesophageal carcinoma (SPEC) (P = 0.005). The incidence of association with pharyngeal malignancy was higher in patients with MPEC than in those with SPEC (P = 0.080). The number of patients in the category representing a combination of heaviest alcohol and cigarette use was significantly higher in the MPEC patients (P = 0.035). The high incidence of MPEC points to a need for careful checking of the oesophagus at the time of surgical treatment for oesophageal carcinoma. Low age at onset, a combination of heavy smoking and drinking, and association with pharyngeal malignancy are considered to be high-risk factors for MPEC.

Aged↗
PubMed1993

Comparison of the alpha-toxin genes of Clostridium perfringens type A and C strains: evidence for extragenic regulation of transcription.

The Clostridium perfringens plc gene encoding phospholipase C (alpha-toxin) was cloned from type C NCIB 10662, a strain which produces low levels of phospholipase C activity. The nucleotide sequence of a cloned 3.1-kb HindIII fragment was determined. The same fragment was also cloned from type A NCTC 8237, a phospholipase C-overproducing strain. In this case, an open reading frame (ORF2) truncated in the previously cloned 2-kb fragment was also sequenced. Comparison of the nucleotide sequence between the 3.1-kb fragments of the two type strains shows some differences both in the plc gene and in ORF2. However, when the 3.1-kb fragment was cloned into plasmid pUC19 and expressed in Escherichia coli, the plc genes from both type strains were similarly expressed and the toxins produced showed similar levels of activity. Northern blot analysis revealed that the type A strain produced 16 to 23 times more plc mRNA than the type C strain. These results indicate that in C. perfringens the two plc genes are transcribed at different rates, probably because of a difference in a locus lying outside of the cloned fragments. Gel retardation analysis showed that the type A strain possessed two different proteins that bound different regions of the plc gene. However, one of these proteins, which binds within the plc coding region, was not found in the type C strain, suggesting that it plays a role in the regulation of the plc gene expression.

Amino Acid Sequence↗
PubMed1992

[Influence of nicardipine on the renin-angiotensin system ina hypertensive crisis during operation in elderly patients].

We studied the influence of nicardipine on renin-angiotensin (RA) system in twelve elderly patients, because the suppression of RA system, the decrease in reactivity of its feedback mechanism, and a high probability of arteriosclerosis and hypertension are well recognized in elderly patients. In hypertensive crisis during operation, intravenous bolus injection of nicardipine was done promptly by anesthesiologists in charge. Plasma renin activity (PRA), angiotensin I (A I), and angiotensin II (A II) were measured with RIA methods before administration of nicardipine and after hemodynamics were stabilized. Changes of systemic arterial pressure and heart rate were simultaneously recorded. Concentrations of PRA, A I, and A II were not significantly elevated, whereas systemic and diastolic blood pressures decreased significantly at 5 min, 15 min, 30 min and 60 min after administration of nicardipine. Heart rate was unchanged. But in a few cases there was an increase in PRA and A I. Average total dose of nicardipine was 26.8 micrograms.kg-1 and average fall of blood pressure was 23.9%. In conclusion, we can use intravenous nicardipine safely and stabilize hemodynamics easily without activation of RA system and rebounding of its feedback mechanism.

Aged↗
PubMed1992

[A case of bronchospasm during induction of isoflurane anesthesia].

Isoflurane is generally considered to prevent increase in bronchomotor tone. We report a case of bronchospasm associated with exposure to isoflurane. A 11-year-old girl was scheduled for tonsillectomy because of repeated fever. Anesthesia was induced with nitrous oxide, oxygen and sevoflurane. Sevoflurane was switched to isoflurane and increased gradually to 3%. Shortly after inhalation of isoflurane, eruption at chest appeared and auscultation of the chest revealed dry rale. Aminophylline and hydrocortisone were injected and isoflurane was discontinued. Ventilation with sevoflurane was started, but there was no improvement. Intramuscular epinephrine was given and sevoflurane was discontinued. After this, the wheezing improved. Four days later she underwent tonsillectomy under sevoflurane anesthesia uneventfully.

Anesthesia, Inhalation↗
PubMed1992

[Appropriate puncture site for CT monitored celiac plexus block determined from CT films].

We investigated appropriate puncture site, angle of needle entry, and the distance of the insertion for CT monitored celiac plexus block using CT photograms on prone position in sixteen patients with gastrointestinal diseases. In retrocrural approach during CT monitored celiac plexus block, the average distances of puncture sites to midline were 3.84 cm on the right and 4.06 cm on the left, and the average needle angles were 74.1 degrees on the right and 76.9 degrees on the left. The average depths from the puncture site to marked position in retrocrural space were 7.88 cm on the right and 7.85 cm on the left. The rates of predicted organ puncture when needle is inserted 7 cm lateral to the midline of the spinal process were 43.8 percent in the right lung, 12.5 percent in the left lung, 56.2 percent in the right kidney and 68.8 percent in the left kidney. From these results, we found high possibilities of organ injuries using the conventional technique for celiac plexus block. We conclude that we could perform celiac plexus block more safely and surely using the retrocrural approach by CT monitoring, as serious complications are avoidable by viewing ideal puncture course on CT photographs.

Aged↗
PubMed1988

Tetraethylammonium-induced contraction of rabbit coronary artery.

The vasoactive effect of tetraethylammonium (TEA), a well-known K channel blocker, was tested on helical strips excised from the large epicardial coronary arteries of rabbit hearts. TEA (10 mM) induced transient tetanic contraction of greater amplitude as a result of summation of twitch responses. Occasionally, spontaneous periodic contractions occurred during prolonged exposure to 10 mM TEA. This TEA-induced contraction was abolished in Ca-free solution and suppressed by Ca-entry blockers: nitroglycerin, nicorandil, and isoproterenol, but not by phentolamine or atropine. In strips in which TEA did not induce remarkable contraction, subsequent addition of a subthreshold concentration of ergonovine, serotonin, acetylcholine, ouabain, K-rich solution, or alkalinization of the solution provoked remarkable contraction. These results are consistent with previous reports that TEA induced tetanic contraction as a result of summation of twitch responses due to spontaneous discharge of Ca-spikes in some arterial and tracheal smooth muscle. The results also support the idea that TEA-induced contraction of the rabbit coronary artery is mediated by the same mechanism, i.e., spontaneous Ca-spike discharge.

Animals↗
PubMed1988

[Effects of a nucleoside and nucleotide mixture on metabolism in hepatectomized rats].

In the present experiment, the effect of a nucleoside-based mixture (OG-VI) on protein synthesis was evaluated. Twenty male Wistar rats weighing about 200g underwent 70% hepatectomy by the Higgins-Anderson's method. All animals were administered standard TPN solution just after operation. The control group received only standard TPN (S-TPN) and the experimental group was given TPN containing 13% v/v of OG-VI (OG-TPN). The rates of whole body protein turnover, synthesis and breakdown measured by the Picou & Taylor-Roberts method with 15N-glycine on the 3rd day after operation. Nitrogen balance on the 1st and 3rd postoperative day and the cumulative nitrogen balance in the OG-TPN group were significantly higher than in controls. Moreover, in the OG-TPN group, protein turnover and protein synthesis were significantly more increased than in the control group. It was thus concluded that the increased protein synthesis, rather than the alteration in protein breakdown, accounted for the good nitrogen balance in the OG-TPN group. The present results strongly suggest that the OG-VI nucleoside and nucleotide mixture improves protein metabolism in hepatectomized rats and helps promoting protein synthesis and turnover after surgical stress.

Animals↗
PubMed1987

Tetraethylammonium induced coronary spasm in isolated perfused rabbit heart: a hypothesis for the mechanism of coronary spasm.

The vasoactive effect of tetraethylammonium, which is known to reduce potassium conductance of the membrane of arterial smooth muscle cells, was tested on large epicardial coronary arteries in isolated perfused rabbit hearts. These hearts were perfused selectively through the right and left coronary arteries. Left coronary angiography was performed using Krebs-Henseleit solution containing phenolsulfonphthalein under constant pressure, and the epicardial electrogram was recorded. In 59 of 114 hearts 30 mmol.litre-1 tetraethylammonium induced severe constriction of the left epicardial coronary artery, which was associated with electrocardiographic ST segment elevation in some cases. The induced spasm was prevented by diltiazem (200 nmol.litre-1), glyceryl trinitrate (2 mumol.litre-1), or nicorandil (10 mumol.litre-1), but not by phentolamine (1 mumol.litre-1) or atropine (1 mumol.litre-1). In hearts in which tetraethylammonium did not induce spasm, subsequent addition of ergonovine (100 nmol.litre-1) or alkalinisation of the perfusate (pH 7.65-7.70) provoked spasm. The tetraethylammonium induced spasm resembled the coronary spasm seen in patients with variant angina and was a reproducible in vitro model of coronary spasm. These observations support the hypothesis that the primary defect in patients with coronary spasm is decreased potassium permeability of the membrane of coronary arterial smooth muscle cells.

Animals↗
PubMedDate not supplied

Effects of total parenteral nutrition with nucleoside and nucleotide mixture on D-galactosamine-induced liver injury in rats.

The effect of a nucleoside-nucleotide mixture on liver injury of rats induced by D-galactosamine was studied by examining changes in function and histopathology of the liver. Animals with liver damage received total parenteral nutrition with glucose and amino acids supplemented with a nucleoside-nucleotide mixture containing inosine, cytidine, GMP, uridine and thymidine, or with uridine which inhibits galactosamine injury, or with liver cell extract containing flavin adenine dinucleotide and nucleic acid derivatives. As control, animals with liver damage received total parenteral nutrition with glucose and amino acids only. The serum GOT and GPT concentrations were significantly lower in the group supplemented with nucleoside-nucleotide mixture than those in other groups. A large dose (1.2 g/kg) of uridine inhibited liver injury, but a lower dose (0.14 g/kg) did not have any effect, whereas nucleoside-nucleotide mixture containing the same amount of uridine inhibited the injury. Liver cell extract also did not improve liver function. Thus infusion of a physiological and balanced mixture of nucleosides or nucleotides may improve liver function in rats with liver injury.

Animals↗
PubMedDate not supplied

Increased cytotoxicity of carbon tetrachloride in a human hepatoma cell line overexpressing cytochrome P450 2E1.

Cytotoxic free radicals generated during the metabolism of carbon tetrachloride by cytochrome P450 2E1 (CYP2E1) are thought to cause hepatotoxicity. Here, the cytotoxic effects of carbon tetrachloride in a liver cell line expressing CYP2E1 (HLE/2E1) are compared with those in the mother cell line (HLE). The effects of carbon tetrachloride on the gene expression of HSP70, a potential marker of oxidative stress, were also examined. The viability of HLE/2E1 cells after exposure to carbon tetrachloride was significantly decreased compared with that of HLE cells. Northern blot analysis revealed that the HSP70 mRNA level was significantly increased after carbon tetrachloride treatment in both cell lines, while the magnitude of its increase was much greater in HLE/2E1 cells than in HLE cells. These results suggest that the oxidative stress induced by CYP2E1 plays an important role in the increase in cytotoxicity of carbon tetrachloride in CYP2E1-overexpressing cells.

Blotting, Northern↗
PubMedDate not supplied

Effect of a nucleoside-nucleotide mixture on protein metabolism in rats after seventy percent hepatectomy.

The effect of a nucleoside-based mixture (OG-VI) on protein synthesis in partially hepatectomized rats was evaluated. Twenty male Wistar rats weighing about 200 g underwent 70% hepatectomy by Higgins and Anderson's method, and then were subjected to total parenteral nutrition (TPN) for 3 days: the control group received only standard TPN (S-TPN group) and the experiment group received standard TPN supplemented with a nucleoside-nucleotide mixture (13% W/V, OG-VI) (OG-TPN group). The rates of whole body protein turnover and protein synthesis and breakdown were determined for 3 days after hepatectomy by the method of Picou and Taylor-Roberts with [15N] glycine. The nitrogen balances on days 1 and 3 and the cumulative nitrogen balance were significantly higher in the OG-TPN group than in the control group. Moreover, the rates of protein turnover and protein synthesis were significantly higher in the OG-TPN group than in the control group. Thus, increase in protein synthesis, rather than change in protein breakdown, was concluded to be responsible for the better nitrogen balance of the OG-TPN group. These findings suggest that the nucleoside-nucleotide mixture was used for the syntheses of RNA and DNA through the salvage pathway in regenerating liver and that this resulted in enhanced protein turnover with simultaneous increase in protein synthesis.

Animals↗