Biomedical subjects

M Kuwahara

Publications and source records attributed to M Kuwahara.

At least 19 recordsLinked to original sources

PubMed1992

Purification and properties of Aspergillus niger beta-glucosidase.

Beta-glucosidase was purified from a crude cellulase preparation from Aspergillus niger by affinity chromatography on a methacrylamide-N-methylene-bis-methacrylamide copolymer bearing cellobiamine. The purified enzyme was a dimer with an isoelectric point of 4.0. The molecular mass of the enzyme was estimated to be 240 kDa by gel-permeation chromatography. The enzyme hydrolyzed specifically beta-glucosidic bonds and catalyzed transglucosylation of the beta-glucosyl group of cellobiose to yield 4-O-beta-gentiobiosylglucose in the presence of organic solvents or under neutral conditions.

Aspergillus niger↗

PubMed1992

Production of endothelin-1 and big-endothelin-1 by pleural mesothelial cells.

Immunoreactive endothelin-1 (ET-1) and big-endothelin-1 (big-ET-1) were detected in conditioned medium of cultured rat pleural mesothelial cells by using sensitive sandwich-type enzyme immunoassay. The amount of both ET-1 and big-ET-1 increased time-dependently. In both instances, maximal amount was detectable in conditioned medium obtained after 72 h in culture (ET-1: 117.1 +/- 30.1 pg/10(6) cells; big-ET-1: 2.4 +/- 2.1 pg/10(6) cells). Fetal calf serum markedly stimulated the production of both ET-1 and big-ET-1.

Animals↗

PubMed1992

Eosinophilic globule cells in mouse MFH-like sarcomas: lectin histochemistry.

Lectin binding patterns in ten mouse malignant fibrous histiocytoma (MFH)-like sarcomas containing eosinophilic globule (EG) cells and in granular metrial gland (GMG) cells of mouse placenta were stained with nine lectins (Con A, LCA, WGA, DBA, SBA, e-PHA, PNA, RCA-I and UEA-I) by an avidin-biotin-peroxidase-complex method. EG cells stained strongly with DBA, SBA and PNA which are specific for N-acetyl-D-galactosamine and/or D-galactose. DBA and SBA bound throughout the cytoplasm including the globules; PNA reacted preferentially at the cell surface. There was no evidence that these three lectins were reactive for immature EG cells. WGA, RCA-I and e-PHA also gave a slightly to moderately positive reaction to globules of EG cells. The results indicate that the globules contain abundant O-linked sequences of sugars, but also a few N-linked residues. MFH tumor cells showed a variable degree of binding with Con A, RCA-I, and WGA, but did not react with DBA, SBA and PNA. On the other hand, GMG cells exhibited specific affinities for DBA, SBA and PNA with staining patterns similar to those of EG cells. These findings suggest that EG and GMG cells may be of the same cellular lineage.

Animals↗

PubMed1992

ECG changes under hyperkalemia with nephrectomy in the rat.

Electrolyte abnormalities have become an increasingly important cause of arrhythmias. Although the electrocardiographic (ECG) changes under hyperkalemia in the rat are poorly understood, it is conceivable that excess plasma potassium may also alter the cardiac excitations in the rat. Further, effects of hyperkalemia on ECG in the rat may differ from other species that have ST-segment and longer QT intervals in ECG. The present study was designed to determine the diagnostic criteria for ECG manifestations to various levels of plasma potassium concentration. For this purpose, hyperkalemia was induced by nephrectomy with and without infusions. Because it was difficult to produce various levels of plasma potassium concentration by only nephrectomy, we used two kinds of infusions to obtain especially moderate levels of nephrectomy-induced hyperkalemia. ECGs were recorded 24, 36, and 48 hours after nephrectomy. Plasma potassium concentration and number of abnormal ECGs were increased time-dependently. Increased T wave amplitude was present with mild hyperkalemia. The typical T wave change observed with so-called sinoventricular conduction levels of potassium concentration in species with long QT intervals did not occur in the rat. PR interval and QRS duration became slightly shorter within moderate hyperkalemia. P wave disappeared in most rats at potassium levels above 8.0 mEq/l. In advanced hyperkalemia (plasma potassium concentration above 7.5 mEq/l), conduction in all parts of the heart was suppressed. Moreover, sinoventricular conduction appeared. Thus, the diagnostic criteria for ECG manifestations to various levels of plasma potassium concentration in the rat were demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Shock wave and THP-adriamycin for treatment of rabbit's bladder cancer.

Focused high-energy shock waves (6,000 to 10,000 shots) were targeted under ultrasound guidance onto implanted urinary bladder cancer in rabbits to elucidate its effect. Although only focal necrosis of the tumor was seen following 6,000 to 10,000 shots daily for 3 days or following chemotherapy (THP-adriamycin) alone, almost total tumor necrosis was observed following a combined shock-wave therapy for one day and THP-adriamycin administration, demonstrating an additive and/or synergetic effect on rabbit urinary bladder cancer.

Animals↗

PubMed1992

Increased calmodulin levels in fibroblasts from progressive systemic sclerosis.

Calmodulin levels in cultured skin fibroblasts from patients with progressive systemic sclerosis (PSS) and healthy controls were measured by their ability to activate cyclic AMP-phosphodiesterase. Calmodulin levels were significantly increased in PSS fibroblasts compared with normal control fibroblasts. The changes in calmodulin content of PSS fibroblasts were also assessed by a radioimmunoassay. These findings suggest that an elevated level of calmodulin may play a role in the pathogenesis of PSS.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1992

Brief ischemia-reperfusion induces stunning of endothelium in canine coronary artery.

BACKGROUND: Brief ischemic episodes that induce stunning of the myocardium may also induce stunning of the coronary endothelium. To test this hypothesis, we examined both in vivo and in vitro responses of canine coronary arteries exposed to brief ischemia. METHODS AND RESULTS: Functional recovery of the endothelium was examined in vivo during reperfusion after 15 minutes of ischemia. Vasodilatory responses to acetylcholine were severely impaired during the first hour of reperfusion but gradually improved over a 90-minute period after ischemia. The vasoconstrictive response to U46619 was enhanced for the first 30 minutes of reperfusion and returned to normal within 60 minutes. In vitro vasomotor responses to potassium chloride, acetylcholine, bradykinin, and sodium nitroprusside were examined in isolated segments of canine coronary arteries preexposed in vivo to brief ischemia (10-30 minutes) and 20 minutes of reperfusion. The results showed enhanced contractile responses and blunted endothelium-dependent but not endothelium-independent vasodilatory responses of arterial rings subjected to 10 minutes of ischemia. Twenty and 30 minutes of ischemia completely impaired endothelium-dependent vasodilation. When reperfusion was extended to 120 minutes after 15 minutes of ischemia, vasodilatory responses to acetylcholine had recovered by almost 90%. Examination of endothelial integrity by transmission electron microscopy after 10-15 minutes of ischemia revealed no evidence of structural damage. Twenty and 30 minutes of ischemia induced cytoplasmic vacuolation, partial detachment of endothelium, and swelling of cytoplasmic organelles. CONCLUSIONS: These data support the hypothesis that brief ischemia-reperfusion induces stunning of endothelium in which endothelium-dependent vasodilatory function is impaired temporarily without morphological damage.

Acetylcholine↗

PubMed1992

Mineralocorticoids and acidosis regulate H+/HCO3- transport of intercalated cells.

The effects of acidosis and mineralocorticoids on cellular H+/HCO3- transport mechanisms were examined in intercalated cells of the outer stripe of outer medullary collecting duct (OMCDo) from rabbit. Intracellular pH (pHi) of intercalated cells was monitored by fluorescence ratio imaging using 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). pHi recovered from an acid load at 2.8 +/- 0.5 x 10(-3) pHU/s in the absence of ambient Na+. This pHi recovery rate was similar in chronic acidosis induced by NH4Cl loading, but it was enhanced (+111%) by treatment with deoxycorticosterone acetate (DOCA). In a DOCA-treated group, luminal 10 microM SCH28080 and 0.1 mM omeprazole, H(+)-K(+)-ATPase inhibitors, did not change the pHi recovery rate, while luminal 0.5 mM N-ethylmaleimide blocked the rate by 68%. DOCA, but not acidosis, increased (approximately 40%) initial pHi response to bath HCO3- or Cl- reduction in Na(+)-free condition. After an acid load in the absence of Na+ and HCO3-, pHi response to basolateral Na+ addition was stimulated (+66%) by acidosis, but not by DOCA. Our results suggest that (a) mineralocorticoids stimulate H+/HCO3- transport mechanisms involved in transepithelial H+ secretion, i.e., a luminal NEM-sensitive H+ pump and basolateral Na(+)-independent Cl(-)-HCO3- exchange; and (b) acidosis enhances the activity of basolateral Na(+)-H+ exchange that may be responsible for pHi regulation.

Acid-Base Equilibrium↗

PubMed1992

Effects of nanomolar to submillimolar carteolol on noradrenaline release in the absence and presence of uptake1 and uptake2 blockers in guinea pig pulmonary arteries.

Effects of nanomolar to submillimolar carteolol, a non-selective beta-antagonist, on the evoked release at 1 Hz and the spontaneous release in the absence and presence of uptake1 and uptake2 blockers were studied in pulmonary arteries, isolated from guinea pigs, and then preloaded with [3H]noradrenaline. dl-Carteolol at 10(-8), 10(-7) and 10(-6) M applied at the increasing concentrations inhibited the evoked [3H]-release in untreated arteries and in desipramine and corticosterone-treated arteries. The spontaneous [3H]-release slightly but significantly increased or tended to increase in untreated arteries. dl-Carteolol at 10(-5) and 10(-4) M clearly and concentration-dependently increased the spontaneous [3H]-release in untreated and cocaine-treated arteries. This increase was markedly inhibited by further pretreatment with normetanephrine. The evoked [3H]-release was not altered by dl-carteolol at 10(-5) M, but increased at 10(-4) M. This increase was not modified by cocaine and by cocaine and normetanephrine. d-Carteolol at 10(-5) and 10(-4) M produced effects similar to those of dl-carteolol. Nanomolar to micromolar dl-carteolol inhibits the evoked [3H]-release, which supports our previous conclusion that this inhibition is due to blockade of tonically functioning presynaptic beta 2-adrenoceptors. Carteolol at the higher concentrations seems to become a substrate for an uptake2 mechanism and to produce an unknown sympathomimetic activity in guinea pig pulmonary arteries.

Animals↗

PubMed1992

Effect of hyperlipidemia on cardiovascular responses to adrenergic stimulation in piglets.

This study was designed to assess the effect of hyperlipidemia on cardiovascular responses to adrenergic stimulation in a porcine model. Four-week-old piglets (n = 10) were divided into two groups; one fed a control diet and the other was fed an atherogenic diet for 8 weeks. Cardiovascular responses were evaluated to both norepinephrine (NE; 0.5 and 2.5 micrograms/kg) and isoproterenol (ISO; 0.1 and 0.5 microgram/kg) from simultaneous recordings of femoral arterial pressure, heart rate, left intraventricular pressure and left intraventricular dP/dt. It was found that no significant difference in the baseline values of cardiovascular function was observed between the control and hyperlipidemic groups. However, in the hyperlipidemic group as compared with the control group: 1) arterial blood pressure responses to NE were significantly increased (P less than 0.05), 2) cardiac contractile responses to NE and ISO were significantly potentiated (P less than 0.05), and 3) reflex bradycardia in response to increasing arterial blood pressure did not occur. These findings indicate that hyperlipidemia can potentiate the cardiovascular responses to adrenergic stimulation, whereas reflex cardiovascular regulation is somewhat altered by hyperlipidemia. Conceivably, these observations may have relevance to the possible role of the mechanism of the interaction of hyperlipidemia and hypertension in atherogenesis.

Analysis of Variance↗

PubMed1992

Effects of atherogenic diet on young farm pigs.

This study was designed to assess the usefulness of young farm pigs as an experimental model for hypercholesterolemia. In order to test this, we investigated both serologic and electrocardiographic effects of atherogenic diet. Four-week-old pigs were fed an atherogenic diet for 8 weeks. No arrhythmia was observed on ECG in all animals. There were no significant difference between control and atherogenic diet group on the values of ECG parameters. However, plasma lipids values of atherogenic diet group were significantly (p less than 0.05) higher than those of control diet group. Thus, hypercholesterolemia was induced in young farm pigs by feeding atherogenic diet in a relatively short time. This fact suggests that young farm pigs may be an useful model for further studies of the effect of hypercholesterolemia on cardiovascular function and the early pathogenesis of atherosclerosis.

Animals↗

PubMed1992

[The pathogenesis of hypercalciuria from the aspect of the response to human parathyroid hormone in Ca containing stone formers].

In order to clarify the pathogenesis of hypercalciuria, the response to extrinsic human parathyroid hormone (h-PTH) was studied the 21 patients with calcium containing urinary stone(s) and 5 normal controls (NO). The stone patients were classified into 3 groups from the result of the oral calcium loading test, i.e. Non-hypercalciura (NH, n = 8) and absorptive hypercalciuria (AH, n = 8) and renal hypercalciuria (RH, n = 5). Only in the AH group, urinary excretion of calcium (u-Ca) was strongly correlated to that of sodium (u-Na) in pre-load of h-PTH, and both increments were also correlated in post-load of h-PTH. As of this fact the increase in Na excretion seems to be responsible for a cause of hypercalciuria in the AH group. There was a significant correlation between the value of %TRP in pre-load of h-PTH and the rate of urinary phosphorus (P) increment between pre-load and post-load of h-PTH in the NO and NH groups. However, this relationship was not found in the AH and RH groups. These findings indicate that there is response disorder of P to h-PTH. In addition, serum P was low, plasma 1,25 (OH)2D was high, N-c-AMP was low in the AH group, whereas both serum P and %TRP were low in the RH group in pre-load of h-PTH. These findings are compatible with the primary renal P leak.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Ultrastructural renal damage after shock wave exposure].

This report clarified the direct damage to renal cell ultrastructure on shock wave exposure. The renal cortex of the rabbit was exposed to the shock waves (1200 bar) generated by the piezo-ceramics. The change was examined by electron microscopy immediately after 20 shots exposure and 500 shots exposure as well as one week after 500 shots exposure. In all groups, the most critical damage was observed in the proximal tubule. Immediately after 20 shots exposure, large vacuoles were found to be enclosed by infoldings in the proximal tubular cell. The damaged cell lost its brush border and jutted out into the lumen. The ruins of organelles (nuclei, mitochondria, etc.) were seen in the lumina of proximal and distal tubules. The damage progressed, in the 500 shots exposure group, to include the distal tubular cytoplasm. One week after the 500 shots exposure, a few of atrophic tubular cells were found in wide scars. The tubular cell which contained a deformed nucleus and destroyed organelles was desquamated from the basement membrane. The change in the tubular cell after shock wave exposure was apparently different from that after such intervention as one hour ischemia. It was concluded that the direct damage to renal cells by underwater shock wave exposure was really present.

Animals↗

PubMed1992

[Clinical significance of HANP (human atrial natriuretic peptide) in patients on maintenance hemodialysis--HANP as a parameter to determine the dry weight (D.W.)].

Human atrial natriuretic peptide (HANP) is a hormone with the physiological characteristics of a regulator of body fluid volume. We studied whether, or not, it is possible to use HANP as a parameter to determine the so-called dry weight (D.W.) in patients on maintenance dialysis. Subjects for experiments included 117 hemodialysis (HD) patients, 18 chronic renal failure (CRF) patients under conservative treatment and 20 normal controls. Plasma HANP level was much higher in HD patients than in controls. In CRF patients treated conservatively, there was no significant correlation between plasma HANP and the degree of renal dysfunction. In HD patients plasma HANP showed a significant positive correlation with CTR (r = 0.408, p less than 0.001), but no correlation with the age or duration of hemodialysis. During hemodialysis, the plasma HANP level fell with the lapse of time significantly (p less than 0.001). In HD patients without complications, plasma HANP level after HD were significantly higher (p less than 0.001) in ones with CTR of 50% or more than with CTR of less than 50%. Plasma HANP may play an important part in regulating the balance of body fluid volume. These findings suggest that plasma HANP is useful as a parameter to determine the D.W. in patients on hemodialysis.

Adolescent↗

PubMed1991

Molecular analysis of a Bjerkandera adusta lignin peroxidase gene.

A cDNA clone, lambda LPO-1, encoding a major lignin peroxidase from the basidiomycete Bjerkandera adusta was isolated and characterized. The nucleotide sequence of lambda LPO-1 predicts a mature protein consisting of 349 amino acids with a molecular weight of 37,225 preceded by a signal peptide of 23 amino acid residues. We have also cloned and sequenced the gene encoding lignin peroxidase from B. adusta. Comparison of these sequences reveals a lignin peroxidase gene structure consisting of 1,116 bp of protein-encoding DNA that is interrupted by four intervening sequences. The putative eukaryotic regulatory sequence, a TATA box, is present at position -75 relative to the translational initiation codon. Amino acid sequence homology between the coding regions of lambda LPO-1 and of the lignin peroxidase cDNA clone lambda ML-1 from Phanerochaete chrysosporium is 61%.

Amino Acid Sequence↗

PubMed1991

Comprehensive treatment of bilateral cleft lip by multidisciplinary team approach.

Repair of bilateral cleft lip presents numerous problems, and in our opinion, it is better to begin treatment at the earliest age possible. At Fujita Health University Hospital, we utilise a multidisciplinary team approach to cleft lip. Nonsurgical correction of the nasal deformity using a nose retainer and preoperative orthodontics using a Kuwahara-modified Hotz's palatal plate begins soon after birth. Surgical repair of the lip is done within the first 2 months of life, by the time the nose, alveolus and projecting prolabium are adequately reformed. A one-stage surgical procedure, including restoration of muscle union, labial sulcus construction and nasal correction is performed. After lip repair, lip and tongue pressure are well balanced by the plate, and a good alignment of the alveolus can be achieved. A total of 27 cases of bilateral cleft lip were treated from August 1986 to October 1990. In all cases, the postoperative course was uneventful, and no complications due to early surgery were encountered.

Cleft Lip↗

PubMed1991

High energy underwater shock wave treatment on implanted urinary bladder cancer in rabbits.

The effects of focused high energy shock waves (SW) on the implanted urinary bladder cancer in rabbits were examined. The bladder cancer was exposed to 2000 to 8000 shots of focused SW under ultrasound guidance. Although only focal necrosis of the tumor was seen in the one day SW exposure, wider and deeper tumor necrosis was observed in the tumors following serial SW (2000 to 6000 shots, for two to three days). Eight to 10 day serial SW exposure (6000 to 8000 shots) decreased the tumor growth in comparison with that of the control. Lung metastases examined by periodic chest X-ray after SW treatment revealed that SW did not promote lung metastases. Pathological findings were also in accord with the X-ray examinations. Polyclonal antibody type 4 collagen was used for immunohistochemical staining of vascular wall in bladder cancer. Vascular wall destruction, not found in spontaneous necrotic tumor, were clearly visible in SW induced necrotic area. SW induces vascular damage in the tumor, which may be the primary cause promoting the tumor necrosis.

Animals↗

PubMed1991

Coronary artery ultrastructural changes in cardiac transplant atherosclerosis in the rabbit.

Accelerated coronary atherosclerosis is the limiting factor for long-term survival of cardiac transplant recipients, but its pathogenesis is poorly understood. Morphologic and ultrastructural changes in suitable models may help explain the underlying mechanisms. In this study, early (3, 7, 14, and 21 days) and late (42 days) ultrastructural changes of the coronary artery were characterized in rabbit cardiac allografts. Thirty-four New Zealand white male rabbits (3.0-4.0 kg) served as donors and recipients. All recipients received cyclosporine (10 mg/kg/day i.m.) as immunosuppressant. In order to increase the normally very low cholesterol levels in rabbits, both the donor and recipient animals were fed a 0.5% cholesterol diet. Recipient animals were sacrificed between 3 days and 6 weeks after transplantation. The specimens from both donor and recipient were examined by transmission electron microscopy, immunohistochemistry, and morphometry. Our data indicate that intimal thickening was initiated with smooth muscle cell migration within 1 week after transplantation, and occurrence of macrophage-derived foam cells and vacuolized smooth muscle cells 3 weeks after transplantation. These changes occurred in the presence of an ultrastructurally intact endothelium. Platelets were only seldom seen adhering to the endothelium. In contrast, lymphocytes and monocytes were frequently found adhering to the endothelium at 2 and 3 weeks posttransplantation. From 3 weeks posttransplantation, lymphocytes were seen only occasionally in the intima but not in the media. This study suggests that early events elicit a change in the smooth muscle cells in the media to the secretory phenotype that migrates to the intima and proliferate. Lymphocyte and monocyte adhesion to the endothelium may enhance smooth muscle migration and proliferation. The large macrophage involvement may relate to the high serum cholesterol levels induced by the cholesterol diet. All these changes occurred in the presence of a structurally normal endothelium and without apparent platelet involvement.

Animals↗