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Biomedical subjects

Y Shimizu

Publications and source records attributed to Y Shimizu.

At least 289 records · Page 16Linked to original sources
PubMed1999

Severe pulmonary hemorrhage in patients with serious group A streptococcal infections: report of two cases.

Severe pulmonary hemorrhage was observed in two patients who died of serious group A streptococcal infections. These two patients initially presented with fever and sore throat. This was followed by sudden onset of septicemia caused by the bacteria and by the subsequent development of severe pulmonary hemorrhage. Hemoptysis, cyanosis, and dyspnea were observed prior to death in both cases. This pulmonary lesion resulted in asphyxia and sudden death in one patient. Pathological examinations of the lung revealed severe intraalveolar hemorrhage, with no evidence of inflammation or necrosis of the pulmonary tissue. There was no evidence of aspiration of blood due to hemorrhage in the upper respiratory or alimentary tract. This visceral lesion appears to be an hitherto undescribed, novel clinicopathologic feature of patients with serious group A streptococcal infections.

Adult↗
PubMed1999

Stimulation of beta1-integrin function by epidermal growth factor and heregulin-beta has distinct requirements for erbB2 but a similar dependence on phosphoinositide 3-OH kinase.

Integrins and growth factor receptors are important participants in cellular adhesion and migration. The EGF receptor (EGFR) family of tyrosine kinases and the beta1-integrin adhesion receptors are of particular interest, given the implication for their involvement in the initiation and progression of tumorigenesis. We used adhesion and chemotaxis assays to further elucidate the relationship between these two families of transmembrane signaling molecules. Specifically, we examined integrin-mediated adhesive and migratory characteristics of the metastatic breast carcinoma cell line MDA-MB-435 in response to stimulation with growth factors that bind to and activate the EGFR or erbB3 in these cells. Although ligand engagement of the EGFR stimulated modest beta1-dependent increases in cell adhesion and motility, heregulin-beta (HRGbeta) binding to the erbB3 receptor initiated rapid and potent induction of breast carcinoma cell adhesion and migration and required dimerization of erbB3 with erbB2. Pharmacologic inhibitors of phosphoinositide 3-OH kinase (PI 3-K) or transient expression of dominant negative forms of PI 3-K inhibited both EGF- and HRGbeta-mediated adhesion and potently blocked HRGbeta- and EGF-induced cell motility. Our results illustrate the critical role of PI 3-K activity in signaling pathways initiated by the EGFR or erbB3 to up-regulate beta1-integrin function.

Breast Neoplasms↗
PubMed1999

Propofol anaesthesia in mice is potentiated by muscimol and reversed by bicuculline.

We have examined the role of gamma-aminobutyric acid (GABA) neurones in propofol anaesthesia in mice using the righting reflex. Propofol i.p. increased the percentage of loss of the righting reflex in a dose-dependent manner with an ED50 value of 140 (95% confidence limits 123-160) mg kg-1 (n = 40; eight animals per dose, five doses per dose-response curve). The ED50 for propofol decreased significantly to 66 (58-75) mg kg-1 in the presence of the GABAA receptor agonist muscimol 1 mg kg-1 i.p. (n = 40) (P < 0.05). In contrast, the ED50 increased significantly to 240 (211-274) mg kg-1 in the presence of the antagonist bicuculline 5 mg kg-1 i.p. (n = 40) (P < 0.05). Our results suggest that propofol anaesthesia may be mediated, at least in part by GABA neurons.

Anesthetics, Local↗
PubMed1999

Role of radical oxygen species in rat testicular germ cell apoptosis induced by heat stress.

The present study was designed to clarify the role of radical oxygen species in testicular germ cell apoptosis induced by heat stress. Testicular cells isolated from immature rats were cultured with or without elevated temperature, and occurrence of apoptosis in these cells was defined by the appearance of DNA fragmentation following agarose gel electrophoresis and by flow cytometric quantification of apoptotic cells. At 32.5 degrees C, < 1% of cells showed signs of apoptosis throughout the culture period, whereas under heat stress, the proportion of apoptotic cells increased to 5% at 37 degrees C after 24 h of culture, or to 14% after 1-h exposure at 43 degrees C followed by 23-h culture at 32.5 degrees C. Similar to the effect of heat stress, exogenously supplied oxygen free radicals also induced apoptosis. In contrast, treatment with catalase significantly attenuated heat stress-induced apoptosis. Furthermore, heat stress of testicular cells was associated with an increased intracellular peroxide level as measured by a fluorescent probe, 2', 7'-dichlorofluorescin diacetate. In conclusion, our data indicate the involvement of radical oxygen species during testicular germ cell apoptosis induced by heat stress. This study provides a useful in vitro model for the study of testicular germ cell apoptosis.

Animals↗
PubMed1999

Clinicopathologic study of esophageal squamous cell carcinoma confined to the mucosa.

The authors studied patients with esophageal squamous cell carcinoma confined to the mucosa (ESCM) with respect to various clinicopathologic factors to investigate the course of invasion of very early-stage esophageal cancers. A total of 74 patients with ESCM were studied. Fifty of these patients had tumor invasion of the basement membrane confined to the lamina propria mucosae (m2 cancer), and 24 patients had tumor invasion of the muscularis mucosa (m3 cancer). All lesions were investigated with regard to clinicopathologic factors such as tumor differentiation, pattern of invasion, endoscopic morphology, and inflammatory response. The patients were divided into groups of 8 patients with positive lymphatic invasion, lymph node involvement, or both (Inv[+] group), and a group of 66 patients with no lymphatic invasion or lymph node involvement (Inv[-] group). The inflammatory response was evaluated on the basis of lymphocyte infiltration at the tumor invasion front and lymphocytic follicles beneath the tumor invasion front. Mean lesion size was significantly greater in the Inv(+) group than in the Inv(-) group (p < 0.05). However, there was no significant difference in the mean area of invasion of the lamina propria mucosae or deeper between the Inv(+) group and Inv(-) group. Patients with m2 cancer had a significantly higher rate of high-degree lymphocytic follicles than those with m3 cancer (p < 0.01). In patients with m2 cancer, the mean area of invasion of the lamina propria mucosae in patients with high-degree lymphocytic follicles was significantly greater than that in patients with low-degree lymphocytic follicles (p < 0.05), whereas there was no significant difference in mean lesion size between patients with high-degree and low-degree lymphocytic follicles. In patients with ESCM, lesion size was an important risk factor for lymphatic invasion and nodal involvement, lymphocytic follicles were prominent beneath the front of relatively broad cancer invasion, and lymphocytic follicles were less common with deeper cancer invasion.

Carcinoma, Squamous Cell↗
PubMed1999

Langer-Giedion syndrome associated with submucous cleft palate.

We report a 4-year-old girl with characteristic features of the Langer-Giedion syndrome (trichorhinophalangeal syndrome type II) who also had submucous cleft palate. When she underwent a palatoplasty, a diagnosis of Langer-Giedion syndrome was made because of the characteristic facial features, multiple exostoses, and partial deletion of the long arm of chromosome 8. This is the first case of trichorhinophalangeal syndrome associated with cleft palate. We review the clinical alterations of trichorhinophalangeal syndromes and differential diagnosis of Langer-Giedion syndrome from trichorhinophalangeal syndrome type I and hereditary multiple exostoses. We also describe the importance of trichorhinophalangeal syndrome in plastic surgery.

Cephalometry↗
PubMed1999

Combined system of biomicroscopic vitreous videography and photography.

PURPOSE: To combine the techniques of biomicroscopic vitreous videography and vitreous photography when examining patients with age- or disease-related vitreous changes. METHODS: We performed biomicroscopic vitreous videography and photography using the newly developed digital photo camera (one-half-inch three-charged coupled device camera with high resolution of 800 x 800 television lines) connected to a slit-lamp biomicroscope and compared it with conventional 35-mm slit-lamp photography in 24 consecutive eyes of 19 patients with idiopathic macular breaks. RESULTS: Stage 1 macular breaks were found in three eyes, stage 2 in four eyes, stage 3 in 11 eyes, and stage 4 in six eyes. Both vitreous videographs and still photographs were recorded and reviewed rapidly in one system. Using this system, dynamic vitreous changes and still vitreous images were documented clearly with real-time television monitoring without using flash illumination. The still images obtained from this system were better than those obtained using conventional 35-mm slit-lamp photography in cases with stage 1, 2, and 3 macular breaks (P = 0.0000000001 by Fisher's exact test). CONCLUSION: This combined system of biomicroscopic vitreous videography and photography may become the standard system of biomicroscopic vitreous examination.

Aged↗
PubMed1999

Enhanced polymorphonuclear neutrophil-mediated endothelial cell injury and its relation to high surgical mortality rate in cirrhotic patients.

OBJECTIVE: A high incidence of complications has been documented in patients with cirrhosis after operations. Recently, polymorphonuclear neutrophils (PMN) have been revealed to have the capacity to injure vascular endothelium and to cause organ damage. Furthermore, the altered function of PMN has been shown in patients with cirrhosis. However, there are few reports investigating the interaction between PMN and endothelial cells and its relation to a high incidence of postoperative complications in cirrhosis. The aim of this study was to evaluate PMN-mediated endothelial cell injury in patients with cirrhosis. METHODS: Patients were divided into two groups: those who had normal liver with metastatic liver carcinoma and those who had cirrhosis with hepatocellular carcinoma. All patients in both groups underwent hepatic resection. PMN were isolated from patients before operation. Human umbilical vein endothelial cells and PMN were cocultured after addition of phorbol myristate acetate. The release of lactate dehydrogenase (LDH) and thrombomodulin in the cocultured medium and the elastase activity in PMN suspension were measured. RESULTS: The release of both LDH and thrombomodulin in the group with cirrhosis was significantly higher than in the group with normal liver. The elastase activity was similarly higher in the group with cirrhosis than in the group with normal liver. The surgical morbidity rate was remarkably higher in the group with cirrhosis (50%) than in the group with normal liver (0%). CONCLUSIONS: This study shows that PMN have an enhanced potential to cause endothelial cell injury in patients with cirrhosis. This PMN "priming" may be responsible for the occurrence of postoperative complications in patients with cirrhosis after hepatectomy.

Adult↗
PubMed1999

Age-related changes in cellular activity in human submandibular glands as evaluated by argyrophilic nucleolar organizer regions.

OBJECTIVE: To examine the age-related changes in cellular activity of epithelial components of human submandibular glands, evaluated on the basis of argyrophilic nucleolar organizer regions (AgNORs). DESIGN: Epithelial components of human submandibular glands were divided into serous acinar cells, mucous acinar cells, intercalated duct cells, striated duct cells, and interlobular duct cells. The mean AgNOR number of each cell type was compared among six age groups. SETTING: The study was conducted at the Department of Oral Pathology, Tohoku University School of Dentistry, Japan. SUBJECTS: Necropsy specimens from 66 males and 57 females 1 to 97 years old. RESULTS: In all cell types except for intercalated duct cells, the mean AgNOR number was lowest in the 0-14 year-old group and highest in the 15-29 year-old group. The value then gradually decreased with advancing age and ultimately reached a similar level to that in the 0-14 year-old group. In intercalated duct cells, the mean AgNOR number did not differ significantly between any age group. There were no significant sex-related differences. CONCLUSIONS: The cellular activity of almost all components of human submandibular glands rises in adolescence and young adulthood and then decreases with aging. These results suggest that intercalated duct cells are capable of not only proliferation but also division into other components; these cells may thus compensate for the reduced activity of other components in elderly subjects.

Adolescent↗
PubMed1999

Acute cerebellar ataxia with human parvovirus B19 infection.

A 2 year old boy developed acute cerebellar ataxia in association with erythema infectiosum. During the disease, genomic DNA and antibodies against human parvovirus B19 were detected in serum but not in cerebrospinal fluid. Parvovirus B19 associated acute cerebellar ataxia might occur due to transient vascular reaction in the cerebellum during infection.

Acute Disease↗
PubMed1999

Low environmental temperature modulates gustatory nerve activity and behavioral responses to NaCl in rats.

We studied the effects of cold ambient temperature on chorda tympani nerve responses to taste stimuli such as sucrose, NaCl, quinine HCl (QHCl), and HCl in rats. The electrophysiological recordings of the whole chorda tympani nerves from control (22 degrees C) and cold-exposed (4 degrees C) rats revealed that the responses to sucrose, HCl, and QHCl were unaffected by cold exposure. In contrast, the nerve responses to NaCl were enhanced time dependently, reaching a maximum 7-14 days after cold exposure. Responses to sodium acetate were likewise elevated as they were to NaCl, whereas those to KCl were unchanged after cold exposure. In addition, the residual NaCl responses after lingual application of the sodium-channel blocker amiloride in cold-exposed rats were similar to those in control animals. It is thus most likely that cold exposure potentiates the chorda tympani nerve responses to Na(+), but not to Cl(-). Behavioral studies with the two-bottle preference test showed that the cold-exposed rats refused to drink NaCl solutions at 0.05 and 0.1 M, the concentrations being preferred by control animals. These results suggest that the ambient temperature influences taste cell function, and that the enhanced NaCl response of the chorda tympani nerve is related to the avoidance of NaCl intake under cold environment.

Amiloride↗
PubMed1999

Is the growth of brown adipocytes necessary for cold acclimation in mice?

Chronic exposure to cold increases the growth of brown adipose tissue and the resistance to more severe cold, thus improving thermogenesis. The present study examined the possibility that dietary compounds can modify cold acclimation. Adenosine (ADO) or adenine (ADE) were administered in drinking water (0.05%, w/v) for 5 weeks to male ddY strain mice from 4 weeks of age. At 5 weeks of age, the mice were exposed to 4 degrees C for 4 weeks. After termination of this period, the interscapular brown adipose tissue (IBAT) and rectal temperature on acute exposure to severe cold (-20 degrees C) for 60 min were measured. Chronic exposure to cold increased the weight of IBAT and made mice resistant to a fall in rectal temperature on exposure to severe cold. The growth of IBAT and improvement in thermogenesis can be used as a cold acclimation profile in ddY mice. The growth of IBAT was selectively prevented by ingestion of ADO. The improvement in thermogenesis was reduced, but only a little, by the ingestion of either ADO or ADE. Thus, growth of brown adipocytes might not be necessary for cold acclimation in mice.

Acclimatization↗
PubMed1999

Conversion of dieldrin to aldrin by intestinal bacteria in rats.

The present study provides the evidence that dieldrin is reductively metabolized to aldrin by intestinal bacteria in rats. When dieldrin was incubated with the cecal contents of rats, aldrin, a reduced metabolite of the epoxide, was isolated from the incubation mixture. The metabolite was identified unequivocally by UV and mass spectral comparison with an authentic sample, and on the basis of its TLC and HPLC behavior. The cecal contents of rats exhibited epoxide reductase activity toward dieldrin under anaerobic conditions. However, only marginal activity was observed under aerobic conditions. Four pure strains of intestinal bacteria exhibited epoxide reductase activities to varying degrees under anaerobic conditions. The highest activity was observed in Clostridium sporogenes. Cell-free extracts of the intestinal bacteria in rat cecal contents showed reductase activity when supplemented with both NAD(P)H and FMN under anaerobic conditions.

Aldrin↗
PubMed1999

[Pharmacological studies of Reiousan, a drug containing bezoar and ginseng--effects on the blood rheology].

Effects of Reiousan, a crude drug preparation consisting of bezoar and ginseng, on blood rheology were studied. Reiousan improved the deformability of rat erythrocytes exposed to hyperosmorality and treated with phenylhydrazine. The ATP depletion in erythrocytes, the polybrene-induced erythrocyte aggregation and the oxidation of low density lipoprotein were suppressed by Reiousan. Oral administration of Reiousan also improved the erythrocyte deformability in phenylhydrazine-treated rats and delayed the thromboembolic death induced by arachidonic acid in mice. These results suggest that Reiousan has an ameliorative effect on blood rheology related to "Oketsu" syndrome in Kampo diagnostics.

Adenosine Triphosphate↗
PubMed1999

Detection of abnormal high-frequency components in the QRS complex by the wavelet transform in patients with idiopathic dilated cardiomyopathy.

In order to investigate whether increased fine, fractionated signals within the QRS complex can detect arrhythmogenic substrates and how these fine signals link with ventricular mechanical dysfunction, wavelet analysis was performed on averaged QRS complexes obtained from the left precordial lead in 26 patients with idiopatic dilated cardiomyopathy (IDCM) and in 12 normal subjects. The number of local maxima and the duration of the wavelet transform were significantly greater in patients with IDCM than in normal subjects; the number at 100 Hz was 8.8+/-3.1 vs 6.0+/-1.1 (p<0.01), and the duration at 100Hz was 93+/-15 vs 75+/-7ms (p<0.01). Both of these indices were greater in the patients with than in those without late potentials, repetitive ventricular premature beats or cardiac death. In addition, significant inverse curvilinear relationships were observed between the left ventricular ejection fraction and both the number of local maxima and the duration of the wavelet transform. In conclusion, fine fragmented signals in the QRS complex detected by wavelet analysis would be an important marker for potentially arrhythmogenic substrates and seemed to progress in parallel with left ventricular mechanical dysfunction in IDCM.

Adolescent↗
PubMed1999

IPD-1151T (suplatast tosilate) inhibits interleukin (IL)-13 release but not IL-4 release from basophils.

The effect of suplatast tosilate (IPD-1151T), which is known to suppress interleukin (IL)-4 release from T cells, on the release of IL-4 and IL-13 from human peripheral basophils was investigated. Basophils were obtained from 16 mite-sensitive atopic asthmatic patients. IPD-1151T clearly inhibited the antigen-induced release of IL-13 but not IL-4. These results suggest that IPD-1151T possesses different activity for the regulation of cytokine release in basophils and T cells.

Adult↗