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Biomedical subjects

J Shimizu

Publications and source records attributed to J Shimizu.

At least 19 recordsLinked to original sources
PubMed2003

[Anomalous systemic arterial supply to the basal segment of the left lung; report of a case].

A 35-year-old female was admitted to our hospital for hysteromyoma. Chest X-ray showed a mass shadow in the left lung field. A thorough examination revealed anomalous systemic arterial supply to the basal segment of the left lung with 2 abnormal arteries. Because the patient had no symptoms, no operation was performed. After 9 months however, the patient had bloody phlegm and chest pain and received an operation. Thus, we propose that the operation for the pulmonary sequestration is to be performed when such a diagnosis is made.

Adult↗
PubMed2002

Distal myopathy with rimmed vacuoles: novel mutations in the GNE gene.

The authors present three novel missense mutations in the UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) gene, the causative gene for hereditary inclusion body myopathy, in Japanese patients with distal myopathy with rimmed vacuoles. Seven out of nine patients had homozygous V572L mutation, one was a compound heterozygote with C303V and V572L mutations, and the remaining patient bore homozygous A631V mutation.

Adolescent↗
PubMed2001

Upregulation of the pro-apoptotic BH3-only peptide harakiri in spinal neurons of amyotrophic lateral sclerosis patients.

DNA fragmentation and activation of caspase-1, implicating involvement of apoptosis, have been reported in the spinal cord of amyotrophic lateral sclerosis (ALS) patients and transgenic mouse models of ALS. Because BH3-only members of the Bcl-2 family have pro-apoptotic activity, we examined the expression of the BH3-only peptide harakiri (Hrk) in the spinal cord of ALS patients. In situ expression of Hrk mRNA and immunoreactivity against the Hrk peptide were verified in the spinal neurons. In the immunoblot analysis, upregulated Hrk protein migrated at 16 kDa. Heterodimerization of Hrk with Bcl-2 was detected by immunoprecipitation, which suggests the competition of Hrk and anti-apoptotic Bcl-2. These findings suggest that Hrk plays a role in apoptotic events in ALS pathogenesis.

Adult↗
PubMed2001

Microwave coagulation therapy with interruption of hepatic blood in- or outflow: an experimental study.

PURPOSE: To determine how interruption of hepatic blood in- or outflow affects the coagulation diameter of microwave coagulation therapy (MCT) in the liver. MATERIALS AND METHODS: Laparotomic MCT at 60 W for 1 minute was performed in 11 Landrace pigs. MCT was performed under six different conditions: without occlusion (Group N; in seven lobes of seven pigs); with occlusion of the hepatic artery (Group A; in five lobes of five pigs); with occlusion of the portal vein (Group P; in five lobes of five pigs); with occlusion of the hepatic artery and portal vein (Group AP; in six lobes of six pigs); with occlusion of the hepatic vein (Group V; in five lobes of four pigs); and with occlusion of the hepatic artery and vein (Group AV; in seven lobes of seven pigs). The maximum diameters for each group were compared. RESULTS: The coagulation diameters (mean +/- SD) were 8.5 mm +/- 2.0, 10.0 mm +/- 1.6, 14.3 mm +/- 2.5, 14.4 mm +/- 2.4, 13.0 mm +/- 0.8, and 14.4 mm +/- 1.5 for Groups N, A, P, AP, V, and AV, respectively. The coagulation diameters for groups P, AP, V, and AV were statistically larger than those for groups N and A (P < .05). There was no significant difference between the coagulation diameters of Groups P, AP, V, and AV. CONCLUSION: The coagulation diameter depends mainly on the portal venous flow. In addition of direct interruption of the portal vein, interruption of the hepatic vein can also result in a substantial increase in the coagulation diameter.

Animals↗
PubMed2001

Immunologic self tolerance maintained by T-cell-mediated control of self-reactive T cells: implications for autoimmunity and tumor immunity.

T-cell-mediated dominant control of self-reactive T cells is one mechanism for maintaining immunologic self tolerance. It also hampers the generation of immunity to autologous tumor cells. Abrogation of the control can evoke potent tumor immunity as well as autoimmunity in normal animals. This common regulatory mechanism for autoimmunity and tumor immunity can be exploited to devise a novel immunotherapy against cancer.

Animals↗
PubMed2001

Evaluation of regional liver damage by magnetic resonance imaging with superparamagnetic iron oxide in rat liver.

The purpose of this study was to investigate whether regional liver damage could be detected by means of enhanced MR imaging with a superparamagnetic iron oxide (SH U 555A) in an ischemia-reperfusion model of rat liver. Ischemic liver damage was induced in the right lobe by vascular clamping for 0 (sham), 30 (I-30), 60 (I-60), and 90 minutes (I-90). There was no significant difference in relative enhancement (RE) between the ischemic and nonischemic lobes in the sham, I-30 and I-60 groups, while RE of the ischemic lobe was significantly lower than that of its nonischemic counterpart in the I-90 group as seen on SH U 555A enhanced proton density spin echo images (P < 0.05). Histological examination revealed that iron deposits were significantly smaller in the ischemic than the nonischemic lobe in the I-90 group (P < 0.05), although there was no significant difference in the number of Kupffer cells. Our results indicate that severe regional liver damage can be evaluated by MR imaging with SH U 555A.

Animals↗
PubMed2001

Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance.

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

Animals↗
PubMed2001

Intrathoracic free musculocutaneous flap after open-window thoracostomy for chronic empyema.

An 85-year-old man was suffering from right pyothorax caused by methicillin-resistant staphylococcus aureus (MRSA). The empyema cavity was closed by intrathoracic implantation of a free rectus abdominis musculocutaneous (MC) flap using microvascular surgery 2 months after open-window thoracostomy (OWT). Compared with a pedicled MC flap, a free flap has the advantage that it can close a larger empyema cavity since the whole flap can be inserted into the cavity. Although the use of a free MC flap requires a two-stage operation, this method is believed to be more successful for controlling chronic empyema than any other established procedure, including decortication, thoracoplasty or pleuropneumonectomy.

Aged↗
PubMed2001

Direct coronary artery perfusion from the left ventricle.

OBJECTIVES: Trends in coronary bypass surgery require less invasive techniques and more conduits. We investigated the ability of direct coronary perfusion from the left ventricle to support regional and global cardiac function. METHODS: A conduit was established between the left ventricle and left anterior descending coronary artery (n = 6) with an interposed Starling resistor that allowed for graded regulation of backward flow. Changes of coronary flow, regional function in the territory of the left anterior descending coronary artery, and reactive hyperemia were studied. In 3 separate dogs, functional tolerance to increased heart rate was tested. In another 3 dogs, left ventricle-left anterior descending and left ventricle-left circumflex coronary artery conduits were established simultaneously (double conduit), and global function was tested. RESULTS: Without flow regulation, flow through the left ventricle-left anterior descending conduit exhibited high peaking (102 +/- 35 mL/min), midsystolic forward flow, and large pandiastolic backward flow (peaking at -47 +/- 22 mL/min). Mean coronary flow and regional function were maintained at 46.0% +/- 7.1% (35.8%-54.2%) and 45.3% +/- 29.1% (-1.8%-74.2%) of their respective normal values. When the Starling resistor was used to regulate backward flow, these values increased to 70.8% +/- 12.5% (56.8%-90.4%) and 70.2% +/- 27.8% (23.6%-107.7%), respectively. Coronary and functional reserve with a left ventricle-left anterior descending conduit were not observed. With the double conduit, global ventricular contractility indexed by end-systolic pressure-volume relation averaged 46% +/- 35% of its normal value. CONCLUSIONS: A left ventricle-coronary artery conduit supplied approximately 45% of normal blood flow and regional function, and both were improved by regulation of backward flow. Therefore, a conduit from the left ventricle to an epicardial vessel could serve as a rapidly deployable means of revascularizing totally occluded coronary vessels for which suitable natural conduits are not available.

Anastomosis, Surgical↗
PubMed2001

Coupling interval from slow to tachycardiac pacing decides sustained alternans pattern.

We discovered that the coupling beat interval from a slow to a tachycardiac pacing period considerably affected the pattern of the beat-to-beat alternation of the tachycardia-induced sustained contractile alternans. We analyzed the relationship between the coupling interval and the pattern and amplitude of the alternans in the isovolumic left ventricle of canine blood-perfused hearts. The alternans pattern and amplitude varied transiently over the first 30-50 beats and became gradually stable over the first minute in all 12 hearts. We discovered that stable alternans, even under the same tachycardiac pacing, had three different strong-weak beat patterns depending on the coupling interval. A relatively short coupling interval produced a representative sustained alternans of the strong and weak beats. A relatively long coupling interval produced a similar sustained alternans but in a reversed order of even- and odd-numbered beats counted from the coupling interval. However, sustained alternans disappeared after 1-3 specific coupling intervals. We conclude that ventricular pacing rate does not solely determine the pattern and amplitude of sustained contractile alternans induced by tachycardia.

Action Potentials↗
PubMed2001

Assessment of segmental wall motion abnormalities using contrast two-dimensional echocardiography in awake mice.

Murine models of cardiac disease are becoming an important tool for studying pathophysiological processes. Development of methods to accurately assess ventricular function are therefore important. The purpose of this study was to evaluate the feasibility of echocardiographic assessment of segmental wall motion abnormalities in a murine model of myocardial infarction. Two-dimensional contrast (C+) and noncontrast (C-) echocardiography were performed in 76 awake mice 2 days before and 2 days after left coronary ligation. The short-axis images obtained with two-dimensional echocardiography and corresponding postmortem cross-sectional histological samples stained with Evans blue dye were each divided into 16 segments, and all matched segments were examined for correlation between wall motion abnormalities and myocardial hypoperfusion. With the use of contrast enhancement, the number of visualized segments was significantly increased (base: C- 86%, C+ 98%; midpapillary: C- 57%, C+ 89%; apex: C- 30%, C+ 74%). Agreement between echocardiographically assessed regional wall motion abnormalities and pathologically determined hypoperfusion in basal, midpapillary, and apical levels were 90%, 93%, and 93%, respectively. Agreement between echocardiographically normal wall motion and pathologically normal findings in basal, midpapillary, and apical levels were 99%, 88%, and 71%, respectively. Thus echocardiographic assessment of segmental wall motion in awake mice was feasible and the accuracy was improved with the use of a contrast agent.

Animals↗
PubMed2001

Anesthetic inhibition in ischemic and nonischemic murine heart: comparison with conscious echocardiographic approach.

It is well known that the level of anesthesia obtained by intraperitoneal injection is variable and may alter cardiac function. In this study, we compared the effects of different anesthetics on cardiac function with the conscious state using high-resolution two-dimensional echocardiography in nonischemic and ischemic mice. Eighty-four mice were tested before and after surgery with ligation of the coronary artery. All 84 mice were studied in the conscious state and under high-dose intraperitoneal anesthesia. Twenty-two of 84 mice were studied under low-dose intraperitoneal anesthesia. Another 22 mice were also studied under gas anesthesia and spontaneous breathing. Experiments in the conscious state were performed by two investigators before the administration of anesthesia: one investigator held the animal and the transducer and the other operated the ultrasound equipment. Left ventricular systolic function was measured, and measurements obtained after surgery were compared with infarcted areas assessed by histological staining. Results showed that both high- and low-dose intraperitoneal anesthesia significantly reduced heart rates and left ventricular contractility in both pre- and postsurgical mice as opposed to conscious mice (P < 0.01). There were significantly higher correlation coefficients between mean fractional area change (FAC) and infarcted area in conscious state compared with high-dose intraperitoneal anesthesia (P < 0.05). The correlation coefficient between FAC and infarcted area during gas anesthesia was also significantly higher compared with high-dose intraperitoneal anesthesia (P < 0.05). In conclusion, conscious experiments or the use of gas anesthesia is preferred for echocardiographic assessment of cardiac function in mice because intraperitoneal injection significantly induces a significant reduction in heart rate and left ventricular systolic function.

Anesthetics, Inhalation↗
PubMed2001

Bronchial sleeve resection with complete preservation of the lung for carcinoma.

Conservative sleeve resection with complete preservation of the lung parenchyma is very rarely applicable for the treatment of bronchial carcinomas. We used this surgical procedure in four patients with bronchial carcinoma in various sites of the central airway, and we obtained successful results. The pathological types were two squamous cell carcinomas and two low-grade malignant tumors (mucoepidermoid carcinoma and adenoid cystic carcinoma). If patients are properly selected, this operative procedure appears to be a safe and radical therapeutic option for the treatment of bronchial neoplasms arising from major bronchi.

Adult↗
PubMed2001

Assessment of left ventricular systolic function using contrast two-dimensional echocardiography with a high-frequency transducer in the awake murine model of myocardial infarction.

The estimation of global left ventricular function using M-mode echocardiography has technical limitations in the murine model of myocardial infarction (MI), but the recent improvements in 2-dimensional (2-D) echocardiography using a high-frequency transducer provide more accessible images. Furthermore, intravenous injection of contrast agent has the additional benefit of enhancing the endocardial border in the murine heart. The present study was designed to evaluate the value of 2-D echocardiography with intravenous injection of contrast agent in the assessment of global systolic function of the murine heart with MI. Two-dimensional and M-mode echocardiography without and with intravenous injection of contrast agent (Optison, 0.1-0.15 ml) were performed in 76 awake mice 2 days before and 2 days after left coronary artery ligation. Fractional shortening (FS) was calculated from the end-diastolic and end-systolic diameters on M-mode echocardiography, and fractional area change (FAC) from the end-diastolic and end-systolic areas on 2-D echocardiography. Both FS and FAC were compared with the areas of hypoperfusion observed in the pathological samples. The use of contrast agent improved the number of hearts that could be evaluated by both the M-mode and 2-D method (M-mode: non-contrast 87% vs contrast 99%, p<0.01; 2-D: non-contrast 26% vs contrast 89%, p<0.001). FAC from the 2-D method correlated better with the region of hypoperfusion in the pathological samples than did FS from the M-mode method (FAC: r=0.84 vs FS: r=0.51). In conclusion, FAC obtained from 2-D contrast echocardiography is useful for noninvasive assessment of global systolic function in infarcted murine hearts and can be used to serially assess systolic function in various models of the murine heart.

Albumins↗
PubMed2001

Dietary curdlan increases proliferation of bifidobacteria in the cecum of rats.

Significant increases in the amounts of short-chain fatty acids and lactate, and in numbers of bifidobacteria were observed in the cecum of curdlan (CD) -fed rats as compared with those of cellulose-fed ones. The in vitro proliferation of 5 species of bifidobacteria was markedly increased in the cultures containing the supernatant obtained from the cecal contents of CD-fed rats. These findings suggest that bifidus factors have been produced in the cecum of CD-fed rats.

Animals↗
PubMed2001

Activation of the adenosine triphosphate sensitive mitochondrial potassium channel is involved in the cardioprotective effect of isoflurane.

The adenosine triphosphate-dependent potassium (K(ATP)) channel has been proposed to play an important role in the cardioprotective effect of isoflurane (ISO). However, the question of whether the K(ATP) channel, sarcolemmal or mitochondrial is the main contributor to the effect has not been clarified. The major aim of the present study was to determine whether or not the mitochondrial potassium channel was a site of action for ISO. Whether there was an acute "memory phase", in which drugs were not detected in the tissues, but the protective effect still remained in the ischemic preconditioning (IP) -like effect of ISO was also investigated. Dangling participle isolated rat hearts, a 20-min normothermic nonperfused phase was maintained to produce a global ischemia. Under these ischemic conditions, the effects of ISO, sodium 5-hydroxydecanoate (5HD: a selective mitochondrial K(ATP) channel antagonist), and ISO combined with 5HD on cardiac performance were examined. To all these four groups, (non-treated group, ISO group, 5HD group and ISO plus 5HD group, n=6 each) drugs were given for 30 min. After 10 min of drug-free perfusion (pre-ischemia restabilization period), 20 min of ischemia followed. Then the cardiac performance and the creatine kinase (CK) release during the reperfusion period were tested. In the non treated group and 5HD group, cardiac performance was stable during the treated period and pre-ischemia the restabilization period. In the ISO group and ISO plus 5HD group, heart rate (HR), left ventricular (LV) systolic pressure, and LV maximum rate of development of tension (dP/dtMax) during the drug-treated period became gradually and linearly worse. However, these values were the same as in the non-treated group and 5HD group at the end of the pre-ischemia restabilization period. So 5HD itself had no hemodynamic effect; nor did it have any influence on the actions of ISO. At the end of the pre-ischemia restabilization period, the significant hemodynamic differences among the groups diminished and ISO was not detected in the solution. In the post-reperfusion period, except for the ISO group, (non treated group, 5HD group and ISO plus 5HD group) cardiac performances were drastically decreased. ISO significantly ameliorated the dysfunction of cardiac output, LV systolic pressure and LV+dP/dtMax. The CK level in the coronary effluent during reperfusion was also significantly reduced by ISO. 5HD completely inhibited these cardiac effects of ISO. Activation of the adenosine triphosphate sensitive mitochondrial potassium channel is involved in the cardioprotective effect of ISO, and the action of this agent has an acute"memory phase" like ischemic preconditioning.

Adenosine Triphosphate↗
PubMed2001

Nephrin is an important component of the barrier system in the testis.

Nephrin, a gene product of the congenital nephrotic syndrome of the Finnish type (NPHS1), is a 1242-residue putative transmembrane protein of the immunoglobulin family of cell adhesion molecules. The expression of this gene is localized in rat and human glomerular epithelial cells. Here we report the expression of nephrin in various tissues other than the kidneys in mice. The expression of nephrin mRNA in various tissues of mice, including the kidneys, testes, spleen, thymus and brain, were first investigated by the RT-PCR method, and it was shown that a high level of nephrin mRNA could be detected in the testes of mice 1-6 weeks old. In situ hybridization revealed the expression of the nephrin gene in the Sertoli cells. Additionally, immunofluorescent staining studies indicated that nephrin was colocalized with anchoring protein ZO-1 in the mouse testis. From these results, it is inferred that nephrin is an important component of the barrier system in testes.

Animals↗