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Biomedical subjects

S Yamazaki

Publications and source records attributed to S Yamazaki.

At least 289 records · Page 16Linked to original sources
PubMed1994

Extracorporeal shock wave lithotripsy (ESWL) for biliary stones: a nationwide survey in Japan.

To assess the current status of extracorporeal shock wave lithotripsy (ESWL) for the treatment of gall-stones in Japan, we conducted a nationwide survey by sending a questionnaire to 251 institutions using this therapy. Replies were obtained from 50 institutions. The use of ESWL was investigated over the period from its introduction up to October 1992. ESWL was performed on 2,760 of 10,058 patients with gallstones (27.4%). The stones were completely pulverized in 1,021 of these 2,760 patients (37.0%). Complete disappearance was limited to single gallstones less than 20 mm in maximum diameter. A comparison in the number of ESWL sessions revealed no significant difference between the patients with and without a good response. Choledocholithiasis was resolved completely in 44.0% of 157 patients who underwent ESWL for this condition and intrahepatic stones were cured in 18.7% of 32 patients. Therefore, ESWL may be a useful form of conservative therapy for biliary calculi.

Cholelithiasis↗
PubMed1994

Tolerance to the vascular effect of a novel nitric oxide-donating vasodilator, FK409.

We investigated whether tolerance develops to the vasorelaxant effects of a new vasodilator, (+-)-(E)-4-ethyl-2-[(E)-hydroxy-imino]-5-nitro-3-hexenamide (FK409), in isolated canine coronary artery strips and to its hypotensive effect in rats, and whether FK409 activates soluble guanylate cyclase isolated from vascular tissues in the absence of L-cysteine. No tolerance to FK409 (0.46 nM to 0.46 microM or 1-1000 micrograms/kg, i.v.) or cross-tolerance between FK409 and glyceryl trinitrate was demonstrated in in vitro and in vivo experiments, whereas the tolerance to glyceryl trinitrate (0.44 nM to 4.4 microM or 1-1000 micrograms/kg, i.v.) was marked in both conditions. In addition, FK409 (0.1-10 microM) activated soluble guanylate cyclase without L-cysteine, but glyceryl trinitrate (1-100 microM) required the addition of L-cysteine (5 mM) for the activation of the enzyme. The results suggest that FK409 may be advantageous compared to tolerance-producing nitrates currently in clinical use, and that this property of FK409 is probably due to its independence of a sulfhydryl group donor.

Animals↗
PubMed1994

Circadian fluctuations of cAMP content in the suprachiasmatic nucleus and the anterior hypothalamus of the rat.

Signal transduction by second messengers has long been hypothesized to be involved in the circadian system in the suprachiasmatic nucleus (SCN) of the mammalian brain. The present study reports that the concentration of adenosine-3',5'-monophosphate (cyclic AMP or cAMP) in the SCN region exhibited a circadian fluctuation with two peaks during a day under constant conditions. While a sharp peak at around the end of the subjective night was observed only in the SCN region, the other peak in the late subjective day was also found in the anterior hypothalamic area. The distinct cAMP peak at the late subjective night contrasts with the daytime peaks in electrical and metabolic activity rhythms of the SCN.

Animals↗
PubMed1994

Reversed-phase high-performance liquid chromatography assay for recombinant acidic fibroblast growth factor in E. coli cell suspensions and lysate samples.

A reversed-phase HPLC assay for acidic Fibroblast Growth Factor (aFGF) expressed in E. coli is described. The assay was developed on a Polymer Labs. PLRP-S macroporous poly(styrene-benzene) column. A sample preparation procedure was developed to permit quantitation of aFGF in crude samples, such as cell suspensions and cell lysates. The assay was linear over the range of 25-140 micrograms/ml with an accuracy of 5%. By using a POROS column containing a stationary phase with "through-pores" and a superficial mobile phase velocity of 1440 cm/h, the analysis could be performed in 3 min. The polymeric supports used for this assay were durable; periodic washing with sodium hydroxide maintained column performance for extended periods.

Chromatography, High Pressure Liquid↗
PubMed1994

Hepatic resection for metastatic tumours from gastric cancer: analysis of prognostic factors.

Determinants of prognosis after hepatic resection for metastasis from gastric cancer were studied in a retrospective series of 21 patients, including four who survived more than 5 years after surgery. All patients underwent apparently curative resection. Synchronous or metachronous resection, age, sex, histological type, depth of invasion, lymphatic and venous invasion, lymph node involvement and number of hepatic metastases were analysed as prognostic factors for survival. Serosal invasion was the only significant determinant at synchronous resection. Both lymphatic and venous invasion were significant prognostic factors available after histological examination. Combined analysis of these two histological variables revealed that patients positive for both were at a significantly higher risk for both overall and disease-free survival. It is suggested that hepatic resection should be attempted in patients with synchronous or metachronous metastases if there is no serosal invasion by the primary gastric tumour, and if the primary tumour has neither venous nor lymphatic invasion in the case of metachronous metastases.

Adult↗
PubMed1994

3'-terminal sequence of a small round structured virus (SRSV) in Japan.

We determined the nucleotide sequence of about 1,000 bases from the 3'-terminus of a small round structured virus (SRSV), which caused a gastroenteritis outbreak in Chiba Prefecture, Japan, in 1987. The sequence was compared with the corresponding sequence region of Norwalk virus; it consisted of a part of the open reading frame 2 (ORF2), whole ORF3, and 3'-noncoding region (NCR). The 624-base-long ORF3 had sequence homology of 68% with the corresponding region of Norwalk virus. (The amino acid sequence homology was 74%.) The 94-base-long NCR had 65% homology with Norwalk virus. We then selected two consensus-sequence portions in the above sequence between Chiba and Norwalk viruses for primers in the reverse transcriptase-polymerase chain reaction (RT-PCR). Using this primer set, we detected 669-bp bands in agarose gel electrophoresis of RT-PCR products from feces containing Chiba or Norwalk viruses. Furthermore, in Southern hybridization with Chiba probes which were labeled with digoxigenin-dUTP in PCR, the bands of the two viruses were clearly stained under a low stringency condition. Since both Chiba and Norwalk viruses were detected by the above primer set although they are geographically and chronologically different viruses, our primer-pair may be useful for detection of a broad range of SRSVs which cause gastroenteritis in different areas.

Base Sequence↗
PubMed1994

Two cases of glutaric aciduria type 1: clinical and neuropathological findings.

We report clinical and neuropathological studies of 2 patients with glutaric aciduria type 1. A 10-month-old male with involuntary movements expired suddenly at home. The second, a 15-year-old female, died after three episodes of acute encephalopathy including a Reye syndrome-like episode and an episode of severe hypoglycemia. Hypocarnitinemia was also present. Selective involvement of type II muscle fibers was observed during the Reye syndrome-like episode. Magnetic resonance imaging of the 2 patients showed marked widening of the sylvian fissure, atrophy of the basal ganglia, and white matter lesions. Neuropathology of the 10-month-old patient showed: (1) temporal and frontal lobe hypoplasia, (2) degeneration of the putamen and the pallidum, (3) mild status spongiosus in the cerebral white matters, (4) heterotopic neurons in the cerebellum, and (5) hypoplasia of the cerebral white matter. This patient appeared to manifest a migration and/or maturation abnormality of the brain as well as previously observed basal ganglia and white matter degeneration.

Adolescent↗
PubMed1994

A large outbreak of acute gastroenteritis associated with astrovirus among students and teachers in Osaka, Japan.

In June 1991, a large outbreak of acute nonbacterial gastroenteritis occurred among students and teachers at 10 primary and 4 junior high schools in Katano City, Osaka, Japan. The outbreak affected > 4700 persons, lasted 5 days, and was believed to have been linked to contaminated food from a common supplier. Astrovirus, identified as the etiologic agent, was detected by direct electron microscopy in 10 of 38 fecal samples obtained from patients with diarrhea. Detection was confirmed by solid-phase immune electron microscopy (IEM), EIA, reverse transcription-polymerase chain reaction, and virus isolation in CaCo-2 cells. Several patients who had astrovirus in their stool also demonstrated a significant antibody response to a reference strain of astrovirus by IEM and EIA and to their own isolate by IEM. Astrovirus can be an important agent of epidemic acute nonbacterial gastroenteritis in school-aged children and adults in Japan.

Acute Disease↗
PubMed1994

Effects of pentobarbital on incorporation of plasma palmitate into rat brain.

BACKGROUND: Barbiturates are reported to reduce brain oxidative metabolism and brain free fatty acid release during ischemia by mechanisms that are as yet unclear. To elucidate their action on brain lipid metabolism, an in vivo method was used to quantify the effect of pentobarbital on the incorporation of radiolabeled palmitic acid from blood into lipids of the rat brain. METHODS: [9,10(-3)H]-Palmitate was infused intravenously in an awake rat or in a rat lightly anesthetized or made comatose by pentobarbital. Twenty minutes after infusion was begun, the rat was killed and non-3H2O radioactivity in individual brain lipid compartments was determined. Incorporation coefficients (k*) were calculated by dividing the lipid compartment radioactivities by the integrated plasma radioactivity to 20 min. RESULTS: Net brain k* for [9,10(-3)H]-palmitate was reduced by 36-40% in pentobarbital-anesthetized rats. This reduction was unrelated to depth of anesthesia or to the presence of hypercapnia and acidosis, because breathing 7.5% CO2 had no effect on k* in awake rats. Anesthesia reduced radiolabel incorporation into phospholipids by 46-53% and into neutral lipids by 20-26% but did not change the distribution of radiolabel among phospholipid or neutral lipid classes. CONCLUSIONS: Pentobarbital has a profound effect on brain lipid metabolism. It reduces incorporation of plasma palmitate into brain, more so into phospholipids than into neutral lipids, independently of changes in cerebral blood flow. Reduced incorporation likely reflects reduced turnover of palmitate within brain lipids (mainly phosphatidylcholine), consistent with evidence that barbiturates also reduce release of free fatty acids during brain ischemia.

Animals↗
PubMed1994

Astrovirus as a cause of gastroenteritis in Japan.

We used an enzyme immunoassay (EIA) to screen for astrovirus in stool specimens from outbreaks and sporadic cases of gastroenteritis collected between 1982 and 1992 in six prefectural public health institutes in Japan. Three outbreaks of gastroenteritis involving schoolchildren and adults were confirmed to be attributable to astrovirus. Astrovirus was detected in 6 to 10% of the specimens from patients with sporadic gastroenteritis from whom no other bacterial or viral agent had been identified. Among the sporadic cases, astrovirus was most frequently detected in infants less than 1 year of age, and the incidence peaked in March and April. Using specimens from recent outbreaks, we found that the EIA was more sensitive than electron microscopy (EM) for the detection of astrovirus, and many EM-negative specimens were positive by EIA. However, some stool specimens previously found to have astrovirus-like particles by EM were negative by EIA, perhaps because of inadequate storage conditions, such as long-term storage and repeated freezings and thawings. Our results indicate that astrovirus is more commonly associated with childhood gastroenteritis than has been previously appreciated and suggest that further studies to examine the epidemiology and disease burden of this virus are needed.

Adolescent↗
PubMed1994

Correlation of ultrasound-measured common carotid artery stiffness with pathological findings.

To quantitatively and noninvasively evaluate common carotid atherosclerosis in a series of patients, we measured the stiffness parameter beta, which represents the mechanical properties of the vessel. beta was calculated from the relationship between blood pressure and the diameter of the artery as measured by an ultrasonic, phase-locked, echotracking system. Increases in the severity grade of atherosclerosis as subsequently determined at autopsy were correlated with increased beta values in 60 common carotid arteries (r = .68). Patients with beta values greater than 13 had a pathological diagnosis of atherosclerosis in the common carotid artery. The sensitivity of this discrimination ratio was 80%, and the specificity was 80% as well. Thus, beta shows promise as a useful diagnostic indicator for detecting asymptomatic common carotid atherosclerosis.

Adult↗
PubMed1994

Existence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols in lipoproteins from diabetic patients and normal subjects.

We report evidence for the presence of 7 alpha- and 7 beta-hydroperoxycholest-5-en-3 beta-ols (cholesterol 7-hydroperoxides, Ch 7 alpha-OOH and Ch 7 beta-OOH, respectively) in human plasma lipoproteins in vivo, which had been reported to be markers of aging in rat skin. A comparative study was carried out focusing on the detection of Ch 7-OOHs in plasma lipoproteins from diabetic patients whose plasma has been suggested to be under high oxidative stress. Blood samples were collected from healthy volunteers (control) and diabetics with and without hypercholesterolemia. Ch 7-OOHs were isolated from low and high density lipoproteins (LDL and HDL, respectively) in the plasma of these subjects, identified, and determined by high-performance liquid chromatography with a chemiluminescence detector. The percent detection of Ch 7-OOHs in LDL from diabetics without hypercholesterolemia was similar to that in the control group. However, it was significantly higher in diabetics with hypercholesterolemia than in those without hypercholesterolemia. The percent detection of Ch 7-OOHs in HDL from diabetics without hypercholesterolemia was higher than both that in LDL from the same group and that in HDL from the control group.

Adult↗
PubMed1994

Epidemics of aseptic meningitis due to echovirus 30 in Japan. A report of the National Epidemiological Surveillance of Infectious Agents in Japan.

Two rages of epidemic of aseptic meningitis (AM) due to echovirus 30 (E30) in Japan were analyzed with respect to two sources of information, AM incidence and E30 isolation, both gathered through the National Epidemiological Surveillance of Infectious Diseases. The first E30 epidemic spread throughout Japan in 1983 and ceased within the year. The second epidemic, starting in 1989, continued for the three successive years, and in the last year, 1991, the total E30 reports numbered 4,061, the largest number of a single virus type ever reported. Although the epidemic showed temporal and geographical shift and lasted for one or two years in some areas, most laboratories reported the largest number of E30 isolation in 1991. Among E30-yielding cases with clinical information during 1982-1992, the associating frequency with AM was as high as 82.5%. Other central nervous system involvements such as encephalitis, myelitis, encephalomyelitis and/or paralysis were reported in 36 E30-yielding cases and their monthly and age distributions were different from those of AM cases. The proportion of such disease among E30-yielding cases (0.60%) was close to that of other enteroviruses (0.56%). During the epidemics, E30 was isolated more frequently from cerebrospinal fluid than was E4 or E9 which prevailed coincidentally. E30 was most frequently isolated from cases of 4-7 years of age, sharing the common characteristic pattern of age distribution with other enteroviral meningitis. E30-yielding cases, however, involved a large number of older age groups than those of other enterovirus infections, and this tendency was the most pronounced in the first epidemic year, 1983. The contribution of these E30 epidemics on the yearly trend of clinically reported AM incidence and on the shift of its age distribution was also analyzed.

Adolescent↗