Biomedical subjects

M Sakaki

Publications and source records attributed to M Sakaki.

At least 19 recordsLinked to original sources

PubMed2004

Genotypic diversity of Salmonella Enteritidis isolates from sporadic patients in limited area during one year.

OBJECTIVES: Our aims were to investigate the genetic epidemiology of Salmonella enterica serovar Enteritidis (S. Enteritidis) isolates using computerized analysis of restriction enzyme cleavage patterns. METHODS: A total of 106 S. Enteritidis isolates which were collected in Hiroshima Prefecture, Japan in 2001 were tested by pulsed-field gel electrophoresis (PFGE) using BlnI and XbaI enzymes. PFGE profiles were analysed and compared by using Fingerprinting II software. RESULTS: BlnI PFGE analysis divided the isolates into 29 genotypes. At 90% similarity, BlnI cleavage grouped the isolates into 15 genotypes, while XbaI cleavage grouped them into only four. Two major clusters, each with a predominant genotype, were identified by BlnI cleavage at 42% similarity. In spite of the mixed circulation of the two predominant genotypes, one genotype for which a number of subtypes were detected was predominant during the first half of the year. In contrast, the other genotype, for which no variant subtypes were detected, followed during the latter half. The genotypes identified by computerized analysis matched well with those judged by visual inspection. CONCLUSIONS: The results confirmed the usefulness of PFGE performed with BlnI and of the Fingerprinting II software for the genotyping of S. Enteritidis. We think that the prevalent characteristics of the predominant genotypes detected here were related to the genetic variations of S. Enteritidis.

Bacterial Typing Techniques↗

PubMed2001

Interaction between emerin and nuclear lamins.

Emerin is an inner nuclear membrane protein that is involved in X-linked recessive Emery-Dreifuss muscular dystrophy (X-EDMD). Although the function of this protein is still unknown, we revealed that C-terminus transmembrane domain-truncated emerin (amino acid 1-225) binds to lamin A with higher affinity than lamin C. Screening for the emerin binding protein and immunoprecipitation analysis showed that lamin A binds to emerin specifically. We also used the yeast two-hybrid system to clarify that this interaction requires the top half of the tail domain (amino acid 384-566) of lamin A. Lamin A and lamin C are alternative splicing products of the lamin A/C gene that is responsible for autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD). These results indicate that the emerin-lamin interaction requires the tail domains of lamin A and lamin C. The data also suggest that the lamin A-specific region (amino acids 567-664) plays some indirect role in the difference in emerin-binding capacity between lamin A and lamin C. This is the first report that refers the difference between lamin A and lamin C in the interaction with emerin. These data also suggest that lamin A is important for nuclear membrane integrity.

Animals↗

PubMed2000

Vasitis nodosa: immunohistochemical findings--case report.

We report the immunohistochemical features of vasitis nodosa and discuss the differential diagnosis. The patient was a 42-year-old Japanese man with bilateral small indurations of the vas deferens at the site of a previous vasectomy. Microscopically, small-sized ducts proliferated within the muscular wall of the vas deferens, and focally in the surrounding connective tissue. Immunohistochemically, most proliferating glandular cells were strongly positive for cytokeratins 7, 19, and 34betaE12, and vimentin. Epithelial membrane antigen and Leu-M1 reacted against the luminal surface of the cells. Focally, glandular cells were also positive for CA125. Cytokeratin 20, carcinoembryonic antigen, and prostate-specific antigen were negative. We discuss the immunohistochemical differentiation of vasitis nodosa from prostatic adenocarcinoma, adenocarcinoma of the rete testis, and adenomatoid tumor.

Adult↗

PubMed2000

Ovarian fibrothecoma with massive edema.

We report a rare case of ovarian fibrothecoma with massive edema. The patient was a 59-year-old woman with a left ovarian mass measuring 11 x 10 x 7 cm. Magnetic resonance images revealed a solid mass showing unhomogeneous content with predominantly high signal intensity on T2-weighted image. Microscopically, the ovarian mass was composed of a cellular area and an edematous hypocellular area. The latter accounted for more than 75% of the tumor. In the cellular area, spindle-shaped or plump tumor cells were randomly distributed or arranged in a fascicular fashion. These cells contained abundant intracytoplasmic lipid. There was dense collagenous connective tissue in the stroma of the cellular areas. In contrast, in the edematous areas spindle or stellate cells were scattered. Alcian blue stain revealed only a small amount of stromal mucin even in the edematous areas. The microscopic findings were consistent with that of fibrothecoma with massive edema. The present case must be differentiated from massive edema of the ovary and sclerosing stromal tumor of the ovary. Immunohistochemistry was not helpful in distinguishing them. The age of the patient and careful histologic observation are important.

Diagnosis, Differential↗

PubMed1999

Double pituitary adenomas: six surgical cases.

While double pituitary adenomas have been found in approximately 1% of autopsy pituitaries, those in surgically resected material have been only rarely reported. We report herein 6 cases of double pituitary adenomas, which consisted of two histologically and/or immunohistochemically different areas among approximately 450 surgical specimens. Five out of 6 patients were men and the age was ranged between 18 and 61 years old. All these 6 patients presented acromegaly or acrogigantism and hyperprolactinemia was noted in 3 patients. In 2 patients (cases 1 and 2) the two adenomas belonged to different adenoma groups (GH-PRL-TSH group and FSH/LH group), while in the remaining 4 patients (cases 3-6) the two adenomas belonged to the same group (GH-PRL-TSH group). Thus, in all patients at least one of the two adenomas was GH-producing adenoma. Reasons for a high incidence of GH-producing adenomas in surgically resected double pituitary adenomas may include the presence of a variety of histologic subtypes among GH-producing adenomas and the advantage of cytokeratin immunostaining to distinguish these subtypes. In regard to pathogenesis of double pituitary adenomas, adenomas in cases 1 and 2 may be of multicentric occurrence, while those in cases 3-6 may occur through different clonal proliferation within originally one adenoma, resulting in diverse phenotypic expressions. Since there were patients with familial MEN 1 (case 2) and familial pituitary adenoma unrelated MEN 1 (case 3), genetic background should be also considered. Double pituitary adenomas in surgically resected material may not be so infrequent. Further molecular analysis will provide new insights into understanding the pathogenesis of pituitary adenomas and their mechanisms of multidirectional phenotypic diffrentiation.

Acromegaly↗

PubMed1998

Prognostic factors in cirrhotic patients receiving long-term sclerotherapy for the first bleeding from oesophageal varices.

OBJECTIVE AND DESIGN: The aim of this study was to identify prognostic factors in cirrhotic patients receiving long-term sclerotherapy for their first bleeding from oesophageal varices. METHODS: Ninety-eight patients with acute bleeding from oesophageal varices receiving long-term endoscopic injection sclerotherapy were retrospectively investigated. Thirteen variables (five qualitative and eight quantitative) related to clinical, biological, and radiographic features were collected at admission. The qualitative variables were: gender, hepatocellular carcinoma, cause of cirrhosis, ascites and degree of encephalopathy. The quantitative variables were age, bilirubin, albumin, prothrombin index, number of sessions of sclerotherapy, volume of ethanolamine oleate, time taken to reach the hospital and shock index. These variables were examined with a multivariate analysis using stepwise logistic regression procedures and a prognostic index was calculated from the Cox equation. The predictive power of the final Cox model was prospectively tested in 43 patients with cirrhosis receiving long-term sclerotherapy for their first variceal bleeding. RESULTS: Of the 13 variables studied in a multivariate analysis using a logistic regression model, four had an independent prognostic value: the presence of hepatocellular carcinoma, bilirubin, albumin and time taken to reach the hospital. When the Cox model was examined in an independent set of 43 patients, there were no statistically significant differences between the observed and expected survival. CONCLUSION: Prognosis of patients with bleeding from oesophageal varices is related to residual liver function and time taken to reach the hospital. Furthermore, the presence of hepatocellular carcinoma is an additional risk factor.

Esophageal and Gastric Varices↗

PubMed1996

HLA-DR8 subtyping by polymerase chain reaction (PCR)-DNA conformation polymorphism (DCP) analysis: a simple and practical genotyping method.

Two hundred Japanese panels were serologically typed for human leukocyte antigen (HLA) - DR to assign 65 HLA-DR8 haplotypes, which were then subdivided into two genotypes, i.e., DRB1*0802 and DRB1*0803, by a polymerase chain reaction (PCR)--based, simple, and practical method. The panels possessing DR8 specificity were firstly subjected to PCR with a couple of primers specifically to amplify their DR52 associated group--DRB1 genes. PCR products were then denatured in the presence of formamide, electrophoresed in a non-denaturing polyacrylamide gel, and visualized by silver staining. The same DRB1 products of these samples were also mixed with the DRB1*1302, and simultaneously analyzed by the same procedure. Electrophoretic mobilities of the samples were compared with those of the typing standards to genotype their DR8--DRB1 alleles by using the characteristic polymorphism in the single-stranded DNAs and the heteroduplexes. This method, designated PCR--DNA conformation polymorphism (DCP) analysis, allowed for genotyping of the DR8-DRB1 alleles without using sequence-specific oligonucleotide probes (SSOP) or restriction endonucleases. The entire process after PCR was completed within a few hours. The tested panels were also genotyped for DRB1 gene by the PCR-SSOP method for comparison with results obtained by the PCR-DCP method. Satisfactory coincidence was achieved and it represented how accurately the new system genotyped DRB1*0802 and DRB1*0803. PCR-DCP analysis was thus shown to be practical and useful for subtyping of serologically defined DR8 specificities.

Base Sequence↗

PubMed1995

Effects of exercise-induced sympathoadrenergic activation on portal blood flow.

We examined the relationship between portal venous blood flow and sympathoadrenergic activation after muscle exercise. For this purpose, we used echo Doppler and measured plasma noradrenaline concentration before and after mild (7 metabolic units, N = 8) and maximal exercise (14 metabolic units, N = 8) in 16 patients without significant disease. Portal venous flow did not change after mild exercise. In contrast, a significant reduction in portal venous flow was observed after maximal exercise (P < 0.01). This was due to reductions in both cross-sectional area of the portal vein (P < 0.01) and portal venous velocity (P < 0.01). Overall, there were significant inverse relationships between the change in plasma noradrenaline concentration and that in cross-sectional area of the portal vein [r = -0.44, P < 0.01 (absolute change); r = -0.47, P < 0.01 (relative change)], that in portal venous velocity (r = -0.63, P < 0.01; r = -0.61, P < 0.01), and that in portal venous flow (r = -0.54, P < 0.01; r = -0.59, P < 0.01). These results suggest that the reduction in portal venous flow after exercise is related to the degree of sympathoadrenergic activation. This reduction may be due mainly to splanchnic vasoconstriction.

Adult↗

PubMed1994

A field isolate of Sendai virus: its high virulence to mice and genetic divergence form prototype strains.

A field isolate of Sendai virus, the Hamamatsu strain, was far more virulent in mice than the prototype Z strain. The Hamamatsu strain replicated more efficiently in the mouse lung than the Z strain, causing deteriorating lung lesions. Nucleotide sequence analysis of the HN, F and M genes revealed that the Hamamatsu strain was divergent from the prototype Z, Harris and Fushimi strains.

Animals↗

PubMed1994

Wedged hepatic venous pressure reflects portal venous pressure during vasoactive drug administration in nonalcoholic cirrhosis.

Hepatic venous catheterization is widely used to assess portal pressure. However, it remains unclear whether wedged hepatic venous pressure is a close indicator of portal venous pressure during vasoactive drug administration in nonalcoholic cirrhosis. To address this issue, we analyzed the data from our previous published studies. Forty patients with nonalcoholic cirrhosis (HBV infection in five, HCV infection in 28, and cryptogenic in seven) were available in this analysis. A vasoconstrictor (N = 14), vasodilator (N = 10), or combination (N = 16) was administered. The agreement of the changes between portal and wedged hepatic venous pressures during pharmacological manipulation was assessed by an intraclass correlation coefficient. The intraclass correlation coefficient in each subgroup was more than 0.60 (0.62 in vasoconstrictor group, 0.87 in vasodilator group, and 0.73 in combination group). When the analysis was performed according to the cause of liver disease, the values were 0.67 in HBV infection, 0.73 in HCV infection, and 0.74 in cryptogenic cirrhosis. These results suggest that wedged hepatic venous pressure reflects portal venous pressure during vasoactive drug administration in patients with nonalcoholic cirrhosis.

Female↗

PubMed1994

Portal pressure after prophylactic sclerotherapy in patients with high-risk varices.

Portal hemodynamics and transhepatic portal venographic findings were studied before and after prophylactic sclerotherapy (mean duration = 40 +/- 14 days) in 16 patients with high-risk esophageal varices. Portal pressure, evaluated by the portal venous pressure gradient, increased by a mean of 21% in eight patients (50%) and decreased by a mean of 20% in eight patients (50%) with no statistically significant change overall. The two groups were further analyzed separately to identify the mechanism of the change in portal pressure. Intrahepatic vascular resistance did not change significantly in either group. However, the prevalence of extravariceal portosystemic shunts was greater in patients with decreased portal pressure than in those with increased portal pressure (88% vs. 25%, p < 0.05). Further, the enlargement of extravariceal portosystemic shunts was more marked in patients with decreased portal pressure than in those with increased portal pressure (88% vs. 0%, p < 0.01). In addition, liver function, assessed by intrinsic clearance, was not modified in the two groups. We conclude that prophylactic sclerotherapy increases or decreases portal pressure without modifying liver function. Although the mechanism of these portal pressure changes is not clear, intrahepatic vascular resistance does not play an important role and the presence of extravariceal portosystemic shunts may prevent further increases in portal pressure.

Esophageal and Gastric Varices↗

PubMed1994

Portal vein hemodynamics in cirrhotic patients with portal hypertensive gastropathy: an echo-Doppler study.

Portal hypertensive gastropathy is a major complication of cirrhosis. The aims of this study were to characterize portal vein hemodynamics and sympathetic nervous activity in cirrhotic patients with gastropathy. Forty-seven cirrhotics (mild gastropathy in 7) and 25 controls were included in this study. Portal vein hemodynamics was assessed by echo-Doppler, and sympathetic nervous activity by plasma adrenaline and noradrenaline concentrations. Portal blood flow was similar in cirrhotics and controls. However, the congestion index of the portal vein (calculated as the ratio of cross-sectional area and blood velocity) was significantly higher in the former than in the latter. Furthermore, the congestion index of the portal vein paralleled the severity of the gastropathy (ANOVA, p < 0.05). Plasma adrenaline and noradrenaline concentrations were higher in cirrhotics than in controls. However, there was no linear relationship between plasma adrenaline (ANOVA, NS) and noradrenaline (ANOVA, NS) concentrations and the severity of gastropathy. These results suggest a relative contribution of "passive congestion" in the pathogenesis of gastropathy.

Aged↗

PubMed1994

Cardiovascular responsiveness after isotonic exercise in cirrhotic patients: study on sympathoadrenergic and renin-angiotensin systems.

OBJECTIVES: The aim of this study was to evaluate cardiovascular responsiveness after isotonic exercise in cirrhotic patients. METHODS: Included were 11 cirrhotic patients and 10 age-matched normal subjects, who served as controls. Hemodynamic data were obtained on each subject before and after muscle exercise on a treadmill (7 metabolic units). Plasma noradrenaline concentration and plasma renin activity also were determined. RESULTS: In both groups, isotonic exercise increased heart rate and systolic arterial pressure, whereas diastolic arterial pressure was not modified. The increase in heart rate and systolic arterial pressure did not differ significantly between the two groups. Plasma noradrenaline concentration and plasma renin activity also were increased. The changes in plasma noradrenaline concentration and plasma renin activity was higher in cirrhotic patients than in controls (p < 0.05, p < 0.05), although the differences were not significant when calculated as a percentage. CONCLUSIONS: Cardiovascular responsiveness to isotonic exercise is almost intact in cirrhotic patients. However, supernormal activation of the sympathoadrenergic and renin-angiotensin systems is required to maintain cardiovascular homeostasis in these patients.

Adult↗

PubMed1994

Influences of nonpulsatile pulmonary flow on pulmonary function. Evaluation in a chronic animal model.

To clarify the influences of nonpulsatile blood flow on the physiologic function of the lung, we established nonpulsatile pulmonary circulation with a centrifugal pump in a chronic animal model (adult goats, n = 6). As the initial phase, a pulsatile right ventricular assist device was implanted to bypass the whole blood supply from both the right atrium and right ventricle to the pulmonary artery. After 2 weeks of pumping, the pulsatile pump was replaced with a centrifugal pump without anesthesia, and nonpulsatile pulmonary circulation was instituted. In this experimental model, no significant change was observed in either mean pulmonary arterial pressure or pulmonary vascular resistance index during the pulsatile pumping compared with that on the fourteenth day of nonpulsatile pumping. Blood gas data, extravascular lung water content, and serum level of angiotensin-converting enzyme were maintained within normal ranges. There was also no significant change in the ventral to dorsal blood perfusion ratio of the lower lobe of the right lung. These results indicate that pulmonary functions are not affected by nonpulsatile pulmonary circulation for a period of 14 days in this animal model.

Animals↗

PubMed1993

Reduced portosystemic hemodynamic responsiveness after orthostasis in patients with cirrhosis.

We studied portosystemic hemodynamic responsiveness after 1 min orthostasis in nine patients with cirrhosis and nine age-matched normal subjects. Orthostasis increased diastolic arterial pressure, which is a close indicator of arterial tone, in normal subjects (+17%, P < 0.01). In contrast, no significant change in diastolic arterial pressure was observed in patients with cirrhosis (-3%, NS). The increase in heart rate was less in patients with cirrhosis than in normal subjects (+15% vs +28%, P < 0.05). Orthostasis also decreased portal blood flow, which was assessed by an echo-Doppler flowmetry, in normal subjects (-27%, P < 0.01), but in patients with cirrhosis it was not modified (-3%, NS). Plasma noradrenaline concentration showed similar increase in both groups (normal vs cirrhosis; +61% vs +55%, NS). Although the change in plasma noradrenaline concentration was related with that in diastolic arterial pressure (r = 0.71, P < 0.05) and inversely with that in portal blood flow (r = -0.69, P < 0.05) in normal subjects, no such significant correlation was found in patients with cirrhosis. We conclude that (1) a reduced hemodynamic responsiveness to sympathetic stimulation exists on both systemic and portohepatic vascular beds and (2) such a blunted baroreflex function is probably located at the receptor or effector level in patients with cirrhosis.

Adult↗

PubMed1993

Effects of vasopressin and nicardipine on hemodynamics and liver function in patients with cirrhosis: comparison with vasopressin alone.

The effects of a combination of vasopressin and a calcium channel blocker (nicardipine) on portohepatic hemodynamics and liver function were compared with the effects of vasopressin alone in 18 patients with portal hypertension. Nine patients received 0.4 units/min of vasopressin and 9 patients received the same dose of vasopressin plus 0.3 mg/min of nicardipine for 40 min. Vasopressin plus nicardipine induced a significant reduction in both free portal venous pressure and the portal venous pressure gradient. These effects were similar to the changes with vasopressin alone (-14% vs. -16% in free portal venous pressure; -29% vs. -31% in portal venous pressure gradient). Vasopressin decreased both hepatic blood flow (-34%, P < 0.01) and intrinsic clearance of indocyanine green (-22%, P < 0.05). In contrast, these two parameters did not significantly change after vasopressin plus nicardipine (-8% and -3%, respectively). These results suggest that the addition of nicardipine improves hepatic impairment induced by vasopressin but causes no further reduction on portal pressure.

Aged↗

PubMed1993

Observer agreement and variability in measuring gastric mucosal blood flow by laser Doppler flowmetry in humans.

We evaluated the reliability (i.e. reproducibility and variability) in measuring regional gastric mucosal blood flow by laser Doppler flowmetry in a total of 32 subjects (12 normal subjects and 20 patients with cirrhosis). The measurements were performed in quadruplicate within 10 min by observer A (A1, A2) and B (B1, B2) using blind techniques. The intraclass correlation coefficient (Ri) was used to assess observer agreement. Overall, the level of intra- (Ri, 0.87 for A1 vs. A2 and 0.87 for B1 vs. B2) and interobserver agreement (0.86 for A vs. B) was excellent. In contrast, there was a higher observer variability assessed by coefficient of variation. Overall, the mean value of coefficient of variation was 12% (max. 35%) for A1 vs. A2, 12% (max. 35%) for B1 vs. B2, and 13% (max. 33%) for A vs. B. These results suggest that laser Doppler flowmetry, although the reproducibility may be clinically acceptable, seems to still be a subjective method for quantitation of gastric mucosal blood flow in humans. Therefore, studies using this method can only be acceptable when the changes that investigators intend to measure are significantly higher than the variability.

Adult↗

PubMed1993

A flow visualization study of centrifugal blood pumps developed for long-term usage.

We have developed centrifugal pumps for long-term circulatory assistance, with the final goal of a completely implantable ventricular assist device or total artificial heart. The previous model, NCVC-0, was characterized by a nonseal design and few flow-stagnating parts and acquired high durability and antithrombogenicity. To improve its pumping performance, NCVC-0 was modified. In the new model, NCVC-1, the profile shape of the impeller was changed from flat to conical, the number of vanes from 4 to 6, and the vane entrance angle from 30 degrees to 60 degrees. A flow visualization study performed by means of a combination of the polystyrene tracer method and the light-cutting method indicated decreased flow turbulence between vanes in NCVC-1, which corresponded well with the increased pumping performance. Flow visualization is a useful method to evaluate the design elements that are closely related to the pumping performance of a centrifugal blood pump.

Equipment Design↗