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Biomedical subjects

H Kanazawa

Publications and source records attributed to H Kanazawa.

At least 109 records · Page 6Linked to original sources
PubMed1997

[Ascending aortic aneurysms operated through redo median sternotomy under selective cerebral perfusion].

Case 1: A 34-year-old man who had received ventricular septal closure at 4 years old was found to suffer from annuloaortic ectasia with severe aortic regurgitation and giant ascending aortic aneurysm accompanying with dissection. Median sternotomy was performed under selective cerebral perfusion to control bleeding when the aorta was injured. He was successfully replaced the ascending aorta and the aortic valve with the composite graft including an aortic prosthetic valve by modified Piehler's procedure. Case 2: A 44-year-old man received mitral valve replacement and tricuspid annuloplasty due to mitral regurgitation with tricuspid regurgitation. After surgery, he suffered from mediastinitis. Three months later, he was found to have pseudoaneurysm of the ascending aorta. During the sternotomy done under selective cerebral perfusion, the pseudoaneurysm was injured but bleeding was controlled easily. The defect of the aorta was closed successfully using a Dacron patch and covered with the right sternocleidomastoid muscle flap. Sternotomy under selective cerebral perfusion is very useful and safe for such patients as to have risks to injure the aorta or the heart during the sternotomy.

Adult↗
PubMed1997

[Diagnosis of shunt dysfunction after transjugular intrahepatic portosystemic shunt by color Doppler ultrasonography: usefulness change of maximum flow velocity in portal vein].

To clarify whether color doppler ultra sonography (CDUS) is useful for the diagnosis of shunt dysfunction after transjugular intrahepatic portosystemic shunt (TIPS), we investigated CDUS in 20 patients who were diagnosed as shunt dysfunction and 12 patients with patent shunt by follow-up portal pressure measurements. In patients with shunt dysfunction, maximum flow velocity in the portal vein (PV-Vmax) and maximum flow velocity in the shunt were significantly decreased in comparison to just after TIPS placement, but not in patients with patent shunt. Grade of color image of the shunt flow and flow direction in the portal vein branches were not significantly different between the shunt dysfunction group and the patent shunt group. Comparing the just after TIPS to the follow-up phase, the decreasing rate of PV-Vmax was negatively correlated with the increasing rate of portal vein pressure caused by shunt dysfunction. CDUS could detect shunt dysfunction in 95% sensitivity, 83% specificity and 91% overall accuracy on the basis of a diagnostic criterion for shunt stenosis : more than 40% decrease of PV-Vmax from just after TIPS insertion. These results suggest that follow-up observation using CDUS is useful for the diagnosis of shunt dysfunction after TIPS procedure, and PV-Vmax is an especially important indicator to detect shunt dysfunction.

Adult↗
PubMed1997

[Aortic arch replacement performed in emergency in a short-term after grafting for abdominal aortic aneurysm].

Two cases of successful staged replacement of multiple aortic aneurysms are reported. Case 1: A 65-year-old man was found to have abdominal aortic and aortic arch aneurysms. He underwent abdominal aneurysmectomy and Y-grafting in the first stage. A month after his discharge, he was transferred to our hospital because of abrupt chest pain. Two days later, he fell into shock and emergent aortic arch replacement was performed successfully. Case 2: A 46-year-old man was transferred to our hospital because of abrupt abdominal pain and shock. CT scan revealed the rupture of the abdominal aneurysm. He received emergent abdominal aneurysmectomy and Y-grafting successfully. Three months later, he was readmitted because of back pain. CT scan revealed DeBakey Type I dissecting aneurysm. After three days, PaO2 of blood gas analysis fell to 46 mmHg, and absent femoral pulsation and oliguria were also observed. Therefore, aortic arch replacement was performed in emergency. The intimal tear was found in the distal aortic arch. The both of cases are doing well 24 months and 10 months after surgery respectively. It is important to scrutinize the order of surgery for multiple aortic aneurysms and to control blood pressure properly after aneurysmectomy.

Aged↗
PubMed1997

[Relationship between exercise-induced hypoxemia and long-term survival in patients with chronic obstructive pulmonary disease].

In patients with chronic obstructive pulmonary disease (COPD), exercise-induced hypoxemia (EIH) is an important limiting factor of exercise performance, but there are very few reports of the prognostic value of EIH. We therefore examined whether EIH is related to long-term outcome in patients with COPD. We gathered data on survival of 77 patients with COPD who had undergone three-minute incremental treadmill exercise tests between 1979 and 1988. A plastic catheter was placed percutaneously into a brachial artery to measure arterial blood gases at each stage of exercise. Expired gas was analyzed continuously during exercise with a Respiromonitor RM-300 (Minato Medical Science). As an index of the severity of EIH we used the delta PaO2/delta VO2 (mmHg/L/min), PaO2-slope. Patients were assigned to two groups according to PaO2-slope, and actuarial survival curves were plotted for the two groups. The survival data were analyzed by generalized Wilcoxon analysis. Survival was significantly better in the group with low PaO2-slopes (< 20 mmHg/L/min) than in the group with high PaO2-slopes (> or = 20 mmHg/ L/min) (p = 0.0031). Also, among the patients in whom PaO2 during exercise was less than 60 mmHg, there was a significant difference in survival between those who received home oxygen therapy and those who did not. We conclude that the degree of EIH can be used to predict survival in patients with COPD, and that the degree of EIH should be considered when prescribing continuous home oxygen therapy for these patients.

Aged↗
PubMed1996

Interactions of the F1-ATPase subunits from Escherichia coli detected by the yeast two-hybrid system.

Subunit interactions among the F1-ATPase subunits were studied by the yeast two-hybrid system. Various pairwise combinations of genes encoding alpha, beta, gamma, delta and epsilon subunits of Escherichia coli H+-ATPase fused to the DNA-binding or activation domain of the yeast GAL4 gene were introduced into yeast and expression of a reporter gene encoding beta-galactosidase was detected. Combinations of the alpha and beta subunit genes, and of the epsilon and gamma subunit genes showed high levels of reporter gene expression, while those of alpha and delta, beta and delta, gamma and delta, and delta and epsilon demonstrated weak but significant reporter gene expression. However, combinations of alpha and gamma, beta and gamma, alpha and epsilon, and beta and epsilon did not induce reporter expression. None of the fused genes alone induced reporter gene expression. These results suggested that specific and strong interactions between the alpha and beta, gamma and epsilon, and weak interactions between the alpha and delta, beta and delta, and gamma and delta subunits occurred in yeast cells in the two-hybrid system. Effects of previously identified mutant beta subunits with Leu-40 to Pro. Glu-41 to Lys or Pro-332 to Gln substitutions which caused defects in molecular assembly of F1-ATPase were analyzed with regard to alpha-beta interactions. No interaction of the alpha and beta subunits was observed in this system using the beta subunit with mutation of Pro-332 to Gln. However, for the other two mutations, alpha-beta interactions were observed. This system may be useful for isolating mutants which have defects in interaction of F1-ATPase subunits.

Escherichia coli↗
PubMed1996

Reconstitution of the F1-ATPase activity from purified alpha, beta, gamma and delta or epsilon subunits with glutathione S-transferase fused at their amino termini.

Systems for overexpression and purification of active alpha, beta and gamma subunits of Escherichia coli H(+)-ATPase were established. The alpha and beta subunits recovered as soluble form were purified by hydroxyapatite column chromatography. Since the gamma subunit was overexpressed as the insoluble form, this subunit was purified by polyacrylamide gel-electrophoresis containing sodium dodecyl sulfate. By subsequent denaturation of this subunit with guanidine hydrochloride and renaturation, the active gamma subunit for reconstitution of the F1-ATPase activity with the purified alpha and beta subunit was obtained. The delta and epsilon subunits which were fused to the carboxy terminus of glutathione S-transferase (GST) were overproduced and purified by affinity chromatography. These fused proteins (delta-GST and epsilon-GST) were incubated with the purified alpha, beta and gamma subunits and applied to affinity chromatography. The alpha beta gamma delta-GST and alpha beta gamma epsilon-GST complex were eluted specifically by addition of glutathione and exhibited high and low ATPase activity, respectively, with a subunit stoichiometry similar to that in the native F1-ATPase, indicating that active complexes could be reconstituted with the fused proteins. These results suggested that the amino-terminal ends of the delta and epsilon subunits are not involved in formation of the active complex. The fused epsilon-GST bound the gamma subunit strongly, and the alpha subunit weakly. The delta-GST bound the gamma subunit significantly, and the alpha and beta subunits very weakly.

Base Sequence↗
PubMed1996

Spontaneous hemopneumothorax.

BACKGROUND: Spontaneous hemopneumothorax is a rare disorder, occurring in 1% to 12% of patients with spontaneous pneumothorax. We studied our previously treated patients to determine the nature of optimal operative management. METHODS: This was a retrospective case study. From 1987 to 1994, of 428 cases of spontaneous pneumothorax that occurred in 234 patients treated at our institution, hemopneumothorax developed in 10 patients (2.3%). The clinical features of these patients were studied. RESULTS: The amount of bleeding ranged from 600 to 1,600 mL, and 3 patients exhibited symptoms of shock, such as sweating, nausea, and syncope. Six patients underwent operation within 7 days from the onset, and this involved resection of the bullae or pneumorrhaphy, or both. The source of bleeding was identified in 5 patients. Pathologic examination showed marked fibrosis with alcian blue-positive deposits of aberrant vessels. All 6 patients continue to be well postoperatively without recurrence or complications. Four patients did not undergo early thoracotomy. However, decortication was required in 3 of these patients because of a reactive fluid collection in the pleural space, which led to impaired lung expansion. CONCLUSIONS: Early surgical repair should be considered once diagnosis of a spontaneous hemopneumothorax is confirmed, because this provides better long-term results. Video-assisted thoracoscopic surgery as well as minithoracotomy should be considered as surgical options because of the improved quality of life they confer.

Adolescent↗
PubMed1996

Choroideremia with leukoencephalopathy and arylsulfatase A pseudodeficiency.

A 33-year-old male patient was admitted to our hospital because of progressive gait disturbance and involuntary movement of the neck. He showed choroideremia, distal motor neuropathy, and leukoencephalopathy on T2-weighted brain magnetic resonance imaging (MRI). Choroideremia is a rare X-linked, progressive, degenerative disease of retina and choroid. There have been some reports of choroideremia patients with neurological complications. Recent studies have assigned its genetic locus to a small segment of Xq21.3 and it encodes a protein that resembles component A of rat Rab geranyl-geranyl transferase, a protein essential for cell function. This patient did not have the reported genetic abnormalities for choroideremia. Known disorders causing leukoencephalopathy were not detected except for a partial deficiency of arylsulfatase A (17.3% of normal controls in lymphocytes and 13.7% in fibroblasts). Deficiency of arylsulfatase A activity occurs in the late infantile, juvenile, and adult forms of metachromatic leukodystrophy (MLD) which is also an inherited disorder of myelin metabolism, but because of its unstability, it occurs in normal individuals and in patients with other neurological diseases. Consequently, we suspect that this patient had partial deficiency of arylsulfatase A and choroideremia as predisposing factors for white matter degeneration.

Adult↗
PubMed1996

An accelerated increase of plasma adrenomedullin in acute asthma.

A novel vasorelaxant peptide, adrenomedullin (AM), has been isolated from the acid extract of human pheochromocytoma. We have recently shown that AM inhibits histamine- and acetylcholine-induced bronchoconstriction in anesthetized guinea pigs in vivo, and this bronchodilatory effect is long-lasting. Here, we measured plasma AM concentrations in nine patients with an acute attack of bronchial asthma. The results were compared with values in 30 age-matched normal control subjects and seven age-matched stable asthmatic patients. The mean AM concentrations of patients with an acute asthma attack (98 +/- 22 pg/mL) were clearly higher than those of normal control subjects (18 +/- 2 pg/mL) and stable asthmatic patients (21 +/- 3 pg/mL). Reverse-phase high-performance liquid chromatography (HPLC) showed that the major component of plasma immunoreactive AM in patients with an asthma attack and in normal subjects equally corresponded to authentic human AM(1-52). Our results suggest that plasma AM is markedly increased in many of the patients during an acute attack of bronchial asthma, but it is not observed in stable asthmatic patients. Although this report is preliminary, the observed increase of circulating AM during an acute asthma attack may represent a compensatory mechanism against the bronchoconstriction, probably through its bronchodilatory action.

Acute Disease↗
PubMed1996

Defective B-1 cell development and impaired immunity against Angiostrongylus cantonensis in IL-5R alpha-deficient mice.

We generated interleukin-5 receptor alpha chain (IL-5R alpha)-deficient (IL-5R alpha-/-) mice by gene targeting. The IL-5R alpha-/- mice showed decreased numbers of B-1 cells concomitant with low serum concentrations of IgM and IgG3. They showed no IL-5-induced enhancement of B cell responses to T-independent antigens. The number of alpha beta T cell receptor-positive thymocytes tended to decrease in 3-week-old IL-5R alpha-/- mice, returning to normal by 6 weeks of age. The IL-5R alpha-/- mice produced basal levels of eosinophils, while their bone marrow cells failed to form eosinophilic colonies in response to IL-5. Impaired eosinophilopoiesis in IL-5R alpha-/-mice enhanced the survival of Angiostrongylus cantonensis. These results indicate that IL-5-induced eosinophils serve as potent effector cells in the killing of Angiostrongylus cantonensis in mice.

Angiostrongylus cantonensis↗
PubMed1996

Critical proline residues of the cytoplasmic domain of the IL-5 receptor alpha chain and its function in IL-5-mediated activation of JAK kinase and STAT5.

The high-affinity receptor (R) for IL-5 consists of a unique alpha chain (IL-5R alpha) and a beta chain (beta c) that is shared with the receptors for IL-3 and granulocyte macrophage colony stimulating factor (GM-CSF). We defined two regions of IL-5R alpha for the IL-5-induced proliferative response, the expression of nuclear proto-oncogenes, and the tyrosine phosphorylation of cellular proteins including beta c, SH2/SH3-containing proteins and JAK2 kinase. In the studies described here, we demonstrate that IL-5, IL-3 or GM-CSF stimulation induces the tyrosine phosphorylation of JAK2, and to a lesser extent JAK1, and of STAT5. Mutational analysis revealed that one of the proline residues, particularly Pro352 and Pro355, in the membrane-proximal proline-rich sequence (Pro352-Pro353-X-Pro355) of the cytoplasmic domain of IL-5R alpha is required for cell proliferation, and for both JAK1 and JAK2 activation. In addition, transfectants expressing chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c responded to IL-5 for proliferation and tyrosine phosphorylation of JAK1. Intriguingly, electrophoretic mobility shift assay analysis revealed that STAT5 was activated in cells showing either JAK1 or JAK2 tyrosine phosphorylation. These results indicate that activation of JAK1, JAK2 and STAT5 is critical to coupling IL-5-induced tyrosine phosphorylation and ultimately mitogenesis, and that Pro352 and Pro355 in the proline-rich sequence appear to play more essential roles in cell growth and in both JAK1/STAT5 and JAK2/STAT5 activation than Pro353 does.

Animals↗
PubMed1996

Potentiation of the bronchoprotective effects of vasoactive intestinal peptide, isoprenaline, and theophylline against histamine challenge in anaesthetised guinea pigs by adrenomedullin.

BACKGROUND: Adrenomedullin is a hypotensive peptide recently discovered in human phaeochromocytoma which has been found to inhibit bronchoconstriction induced by histamine and acetylcholine. This study was designed to determine the manner in which adrenomedullin and other bronchodilators interact in modulating airway function. METHODS: A study was undertaken to determine whether adrenomedullin potentiated the bronchoprotective effects of isoprenaline, vasoactive intestinal peptide (VIP), and theophylline against histamine-induced bronchoconstriction in anaesthetised guinea pigs in vivo. RESULTS: Adrenomedullin in a concentration of 10(-9) M significantly inhibited histamine-induced bronchoconstriction but in a concentration of 10(-10) M it did not exhibit the bronchoprotective effect against histamine. VIP (10(-9) M) did not affect histamine-induced bronchoconstriction but it markedly inhibited the bronchoprotective effect against histamine in the presence of adrenomedullin (10(-10) M). VIP (10(-6) M) significantly inhibited histamine-induced bronchoconstriction but this effect was short lived. Adrenomedullin in a concentration of 10(-10) M potentiated bronchoprotection induced by VIP (10(-6) M) and prolonged it. Isoprenaline (10(-8) M) also significantly inhibited histamine-induced bronchoconstriction and this effect was enhanced in the presence of adrenomedullin (10(-10) M). Similarly, adrenomedullin (10(-10) M) significantly potentiated theophylline-induced bronchoprotection, and a sub-bronchoprotective dose of theophylline (20 mg/kg i.p.) was effective in preventing histamine-induced bronchoconstriction in the presence of adrenomedullin (10(-10) M). CONCLUSIONS: This study shows that adrenomedullin potentiates the bronchoprotective effects of different classes of bronchodilators against histamine challenge in anaesthetised guinea pigs.

Adrenomedullin↗
PubMed1996

Clinical significance of serum concentration of interleukin 8 in patients with bronchial asthma or chronic pulmonary emphysema.

Interleukin-8 (IL-8) belongs to the family of chemotactic cytokines and has been shown to activate neutrophils in vitro and in vivo. In this study, we measured IL-8 concentration in the serum of patients with pulmonary emphysema or bronchial asthma. IL-8 concentration in serum of emphysema patients was significantly higher than in asthmatics; in emphysema patients it was significantly correlated with the smoking index and the annual decrease of FEV1.0. In asthmatics IL-8 concentration was below the level of detection, but was markedly increased during exacerbation of asthma. Our findings suggest that IL-8 may be one of the causal factors in these diseases.

Adolescent↗
PubMed1996

Acidic catecholamine metabolites and 5-hydroxyindoleacetic acid in urine: the influence of diet.

Concentrations of vanillylmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), vanillic acid (VA) and 5-hydroxyindoleacetic acid (5-HIAA) in urine from healthy subjects were determined by a high-performance liquid chromatography system with a mixed-mode (C18/anion-exchange) column and an 8-channel electrochemical detector, in order to study the influence of diet, diurnal variation and age. The urinary excretion of 5-HIAA increased significantly after eating banana, pineapple, tomato, kiwi fruit and walnut. An increase in the urinary excretion of DOPAC and HVA after eating banana and that of VA after taking vanilla was also noted. The urinary excretion of VMA was not significantly influenced by any of the foods examined. The urinary excretion of 5-HIAA in the first-morning urine increased beyond the upper limit of the reference value when banana was taken at 2000 h the previous day. The excretion of all metabolites in the second-morning urine in the fasting state was within respective reference ranges. Diurnal variation of the excretion of VMA, DOPAC, HVA and 5-HIAA in urine was relatively small, but that of VA was large. The concentrations (mmol/mol creatinine) of VMA, DOPAC, HVA, 5-HIAA and VA in the first-morning urine from healthy subjects increased from 7 days after birth to 1 year and then decreased to adult levels at 13 years of age.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Role of endogenous nitric oxide in airflow obstruction in smokers.

OBJECTIVE: The aim of this study was to examine the relationship between endogenous nitric oxide (NO) level and airflow obstruction in smokers using single-breath measurement of exhaled NO with the sequential breath-holding method. SETTING: A university hospital. PATIENTS: Nine nonsmoking and ten smoking healthy volunteers. MEASUREMENTS: NO in exhaled air was measured using a chemiluminescence analyzer. Pulmonary function tests were performed using an autospirometer. RESULTS: The level of exhaled NO was higher in nonsmokers than in smokers, and the difference became larger as the breath-holding time increased. To evaluate the correlation between endogenous NO level and the degree of airflow obstruction in smokers, we used a new parameter, the NO concentration difference (delta NO). Our findings indicate that reduced level of NO in exhaled air is an indicator of decreased NO synthesis within the respiratory system and is associated with the development of airflow obstruction in smokers (r = 0.678; p < 0.01). CONCLUSIONS: delta NO is a good indicator of the synthesis of endogenous NO within the respiratory system, and it appears likely that the reduced synthesis of NO may be a contributing factor to airflow obstruction in smokers.

Adult↗
PubMed1996

The taste bud and its innervation in the rat as studied by immunohistochemistry for PGP 9.5.

The taste bud in the rat vallate papillae was observed by immunohistochemistry for PGP 9.5 at the light and electron microscope levels; routine transmission electron microscopy was also performed. Immunoreactivity for PGP 9.5, a marker protein of paraneurons, was localized in the cytoplasm of the Type III or gustatory cells. More intensive immunoreactivity occurred in the nerve fibers, though a part of the nerve fibers remained unstained. The nerve fibers as detected by the immunostaining and by routine electron microscopy formed a coarse subepithelial plexus which issued branches upwards through the basal lamina. In the basal portion of the taste bud, these fibers formed a hitherto unknown intragemmal plexus of dense and delicate meshwork. This plexus, in turn, extended beaded fibers between the taste bud cells, forming synaptic contacts with Type III cells. Some of the immunoreactive nerve fibers were confirmed to reach the taste pore by light microscopy; electron-microscopic examination could not demonstrate their directly being exposed to the space of the taste pore. This study also deals with the fine structure of the rat taste bud with special reference to the Type III cells and their synapses with nerve fibers, as the rat has recently been rather seldom used in this field of study.

Animals↗
PubMed1996

A possibility of efferent innervation of the gustatory cell in the rat circumvallate taste bud.

A transmission-electron microscope study of the rat circumvallate taste bud revealed that occasionally one and the same gustatory or Type III cell received innervation associated with subsurface cisterns as the Type II cell did, in addition to the ordinary afferent synapse. The subsurface cistern a flattened, smooth-surfaced saccular membrane system, hugged the plasma membrane of the gustatory cell along the boundary against the nerve terminal. The nerve terminal attaching to the cell was occupied with mitochondria and synaptic type vesicles. As these structural features resemble those of efferent synapses in certain other sensory cells including the inner ear hair cells, the gustatory cells dually innervated as demonstrated in the present study are presumably involved not only in the afferent but also in the efferent projection of nerves.

Animals↗