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Biomedical subjects

K Kondo

Publications and source records attributed to K Kondo.

At least 613 records · Page 34Linked to original sources
PubMed1991

Possible involvement of endogenous opioid peptides in the inhibition of arginine vasopressin release by gamma-aminobutyric acid in conscious rats.

We examined the effects of gamma-aminobutyric acid (GABA) and naloxone, a potent opioid antagonist, on arginine vasopressin (AVP) secretion in conscious rats in order to study the relationship of GABA and endogenous opioid peptides in the regulation of AVP secretion. Intracerebroventricular administration of GABA caused a time- and dose-dependent decrease in the plasma concentration of AVP that was elevated by hypertonic saline injection, whereas it did not affect the basal AVP. Pretreatment with naloxone (10 mg/kg) significantly attenuated the inhibitory effect of GABA (100 micrograms) on AVP release. These results suggest that GABA produces an inhibition of AVP release stimulated by hypertonic saline, and that this inhibitory effect may be mediated at least in part by the endogenous opioid systems.

Animals↗
PubMed1991

Frequency of HLA-DQA1 alleles in the Japanese population.

One of the HLA class II genes, HLA-DQA1, was typed from 290 unrelated healthy Japanese using the oligonucleotide typing method. The HLA-DQA1 gene was enzymatically amplified and typed by dot-blot hybridizations with 10 sequence-specific oligonucleotide probes labeled nonradioactively. Using this method, the HLA-DQA1 genotype was theoretically classified into 36 genotypes: 8 homozygous and 28 heterozygous ones. Actually, 26 genotypes were observed in the present study, and the gene frequency of each allele was calculated. The observed numbers were in accordance with the numbers expected under the Hardy-Weinberg equilibrium. The HLA-DQA1 genotype was also determined in aged bloodstains. Since the genotype is polymorphic in the Japanese population and a very small amount of blood is required for determination, this typing is particularly useful for forensic analysis.

Alleles↗
PubMed1991

Autosomal recessive polycystic kidney in rats.

We evaluated the characteristics of renal lesions in rat autosomal recessive polycystic kidney (ARPK). In rat ARPK, small cysts appeared primarily in the medulla 2 months after birth and gradually extended to the cortex, forming large cysts involving the entire layer after 8 months. By immunofluorescence microscopy, type IV collagen was more strongly stained in the epithelial basement membrane of the rat ARPK than in the normal rat tubular basement membrane (TBM). Electron microscopy demonstrated a marked thickening, slight splitting and lamination of the TBM in the ARPK. As peroxidase-labeled lectins, dolichos biflorus very strongly stained the cyst epithelium whereas lens culinaris did not. These findings indicate that cysts in rat ARPK originate in the collecting duct.

Age Factors↗
PubMed1991

Experimental labyrinthitis in guinea pigs caused by a hantavirus.

Hantavirus-induced acute viral infection of the inner ear of guinea pigs is reported. Guinea pigs were inoculated directly into the inner ear through the round window, or intraperitoneally with hantavirus (B-1 strain), and the cochlea was examined using an immunohistochemical technique for the localization of viral antigens. Virus-specific antigens were detected prominently in the stria vascularis and to a lesser degree in other inner ear structures of the infected guinea pigs. The morphological changes in the inner ear structures of these guinea pigs were observed. Virus was isolated from the blood of some infected guinea pigs. These data suggest that hantavirus can infect the inner ear of the guinea pig via viremia. The effect of immunosuppression by ciclosporin A or cyclophosphamide is discussed.

Acute Disease↗
PubMed1991

Body surface distribution of abnormally low QRST areas in patients with left ventricular hypertrophy. An index of repolarization abnormalities.

BACKGROUND: QRST isointegral maps (I-maps) have been useful in detecting repolarization abnormalities. We investigated the body surface distribution of abnormally low QRST areas in patients with left ventricular hypertrophy (LVH) and the relation of the abnormalities in I-map to the severity of LVH as assessed by echocardiography. METHODS AND RESULTS: QRST area departure maps were constructed from electrocardiographic (ECG) data recorded in patients with LVH and precordial negative T waves resulting from aortic stenosis (AS) (10 patients), aortic regurgitation (AR) (12 patients), or hypertrophic cardiomyopathy (HCM) with asymmetric septal hypertrophy (22 patients). Fifty normal subjects served as controls. The I-map was constructed from 87 body surface electrocardiograms recorded simultaneously at a sampling interval of 1 msec. The area where the QRST area was smaller than normal limits (mean -2 SD) was designated the "-2 SD area." The echocardiographic left ventricular (LV) mass was calculated by Devereux's method. Patients with large LV masses due to AS or AR had 2 SD areas located over the left anterior chest or the midanterior chest, respectively. The 2 SD area was located over the left shoulder and left anterior chest and had a lingual shape in patients with HCM. The sum of QRST area values less than the normal range (sigma QRST) was significantly correlated with LV mass in patients with AS or AR (r = 0.83 and r = 0.69, p less than 0.01 and p less than 0.05). However, there was no significant correlation between sigma QRST and the severity of LVH in patients with HCM. sigma QRST divided by the number of electrodes in the 2 SD area was significantly greater in patients with HCM than in those with AS or AR. CONCLUSIONS: These findings suggest that abnormalities in patients with HCM are manifest even in mild LVH and that there is a greater disparity of repolarization in hypertrophied left ventricles due to HCM than in LVH due to aortic valve disease. QRST isointegral departure maps may provide ECG evidence of LV mass of patients with AS or AR and of susceptibility to malignant arrhythmias in patients with HCM.

Aortic Valve Insufficiency↗
PubMed1991

Nematocidal principles in "oakmoss absolute" and nematocidal activity of 2,4-dihydroxybenzoates.

Nematocidal principles obtained from oakmoss absolute were identified as methyl 2,4-dihydroxy-3,6-di-methylbenzoate (2), ethyl 3-formyl-2,4-dihydroxy-6-methylbenzoate (4), and ethyl 5-chloro-3-formyl-2,4-dihydroxy-6-methylbenzoate (7). In relation to their structures, the nematocidal activity of 2,4-dihydroxybenzoates of methyl to tetradecyl was tested and the strongest activity was found in the octyl ester (minimal lethal concentration = 13 microM).

Animals↗
PubMed1991

Prolactin secretion in patients with idiopathic diabetes insipidus.

It has been demonstrated that hyperprolactinemia is sometimes present even in patients with idiopathic diabetes insipidus (DI). In this study, we examined the responses of serum prolactin (PRL) to hypertonic saline infusion and TRH injection in 11 patients with idiopathic DI diagnosed by clinical examinations. Serum sodium in these patients (147.5 +/- 3.2 mEq/L) was significantly higher at baseline than in normal subjects (139.7 +/- 2.4 mEq/L). The plasma arginine vasopressin (AVP) level was significantly lower in DI (0.42 +/- 0.24 pg/ml) at baseline than in normal subjects (2.53 +/- 1.03 pg/ml). However, the serum PRL level in both groups did not differ significantly except in one patient with idiopathic DI (35.6 ng/ml). There was no significant correlation between the basal serum sodium and basal serum PRL in either group. After an infusion of hypertonic saline, the serum sodium level gradually increased to 155.6 +/- 3.4 mEq/L in DI and to 146.5 +/- 4.3 mEq/L in the normal subjects. However, this increase did not affect PRL secretion in either group. PRL response to TRH was essentially normal in all patients with idiopathic DI. These results indicate that the secretion of PRL is not generally affected by chronic mild hypernatremic hypovolemia in the patients with idiopathic DI.

Adolescent↗
PubMed1991

Inhibition of platelet aggregation by low concentrations of sodium fluoride. Significance of the intracellular calcium ion concentration.

Sodium fluoride activates platelets but its mechanism of action has not yet been completely identified. We examined the effect of a low concentration of sodium fluoride (which could not cause aggregation) on thrombin-induced changes in the intracellular calcium ion concentration ([Ca2+]i). In the presence of 1 mM extracellular Ca2+, preincubation with a low concentration of sodium fluoride decreased the peak of the thrombin-induced elevation of [Ca2+]i, when measured with aequorin. When [Ca2+] was measured using fura-2, preincubation caused no marked changes in its peak, but the later changes that were thought to mainly reflect extracellular Ca2+ influx were inhibited. The inhibitory mechanism of sodium fluoride appears to depend on reducing extracellular Ca2+ influx. Aequorin appears to reflect [Ca2+]i near the cell membrane and is thus easily affected by the extracellular Ca2+ influx.

Blood Platelets↗
PubMed1991

Amino acid sequence of the 8-kDa protein in photosystem I reaction center complex from a thermophilic cyanobacterium, Synechococcus elongatus.

The 8-kDa protein in Photosystem I (PS I) reaction center complex was isolated from a thermophilic cyanobacterium, Synechococcus elongatus, by SDS-polyacrylamide gel electrophoresis using TRIS-Tricine buffer system. The complete amino acid sequence of the protein was determined. The 8-kDa protein consisted of 73 amino acid residues giving a calculated molecular weight of 7,472. No significant sequence homology were observed with the known other small subunits in PS I reaction center complex, except for the 6.5-kDa protein in PS I from another thermophilic cyanobacterium, S. vulcanus. The 8-kDa protein was characteristically rich in hydrophobic amino acid residues, especially the content of leucine. These suggest that the 8-kDa subunit is an intrinsic structure component in PS I core complex for stabilization of the reaction center.

Amino Acid Sequence↗
PubMed1991

[Experimental study on the characteristic features of sympathetic nervous system reactions in dogs with obstructive jaundice].

Possible abnormalities in the sympathetic nervous system responsible for circulatory disturbances with obstructive jaundice were investigated by determining the reactions of the heart and peripheral blood vessels using alpha.beta receptor stimulants or blockers. Mongrel dogs were randomly assigned to three groups: untreated (UT) and sham-operated (SO) controls and 3-week-old bile duct ligated (BDL). Under anesthesia with Nembutal, circulatory parameters and blood catecholamine concentration were measured. In term of alpha- and beta-adrenergic reactions, reactions in the sympathetic nervous system to alpha- and beta-receptor stimulants were examined. Mean arterial pressure (MAP) and heart rate were used as an alpha-adrenergic parameter and a beta-adrenergic parameter, respectively. The hemodynamic study in BDL group was characterized by a reduction in MAP (p less than 0.05), total peripheral resistance (p less than 0.005) and left ventricular stroke work (LVSW) (p less than 0.05) and by an increase in cardiac index (p less than 0.05). The blood norepinephrine concentration was significantly increased in jaundice (p less than 0.01). Reaction to the beta-receptor stimulant was significantly decreased in BDL group. In response to the alpha-receptor stimulant, lower reactivity was found in some animals in BDL group in comparison to SO group. Taking this into consideration with the increase in blood norepinephrine and the decrease in LVSW, the presence of abnormalities particularly in the beta-adrenergic system (receptor, cardiac muscle etc.) in jaundice is suggested to be a characteristic feature of reactions in the sympathetic nervous system. Such abnormalities are speculated to be responsible for postoperative shock.

Animals↗
PubMed1991

[Similarity between internal thoracic artery and gastroepiploic artery graft: pharmacological point of view].

The pharmacological responses of internal thoracic artery (ITA), gastroepiploic artery (GEA) and saphenous vein (SV) obtained from patients receiving coronary artery bypass grafting (CABG) were assessed by isometric contraction records. The concentration-response curves for ergonovine and serotonin showed the leftward shift in SV compared with ITA and GEA. The 50% effective dose values of SV for ergonovine and serotonin were significantly less than those of ITA and GEA. The concentration-response curves for phenylephrine were similar among three kinds of grafts. There were no significant differences in the 50% effective dose values for phenylephrine among them. The effect of 0.4% papaverine chloride on the free graft flow was assessed in 15 patients receiving CABG with mean body surface area of 1.62 +/- 0.12 M2. The free flow of ITA graft was 71 +/- 32 ml/min before intraluminal papaverine injection, and that increased to 112 +/- 41 ml/min after injection. The free flow of GEA graft was 82 +/- 39 ml/min before injection, and that also increased to 128 +/- 40 ml/min after injection. The patency rates at the mean 2.2 months after grafting were 98% in ITA, 93% in GEA, and 88% in SV. In conclusion, both GEA graft and ITA graft can be expected as an excellent conduit in myocardial revascularization.

Adult↗
PubMed1991

[Clinical assessment of posterior pituitary function by measurement of unextracted random urine].

To evaluate posterior pituitary function without any provocative examination, vasopressin (AVP) concentrations of random urine were measured by high-sensitive radioimmunoassay (AVP-RIA Kit, Mitsubishi Petrochemical Co., Ltd.). No apparent interference for the AVP measurement in unextracted urine was seen after appropriate dilution of urine sample. Urinary AVP did not degenerate at least for 24 hr at room temperature. AVP concentration of random urine was significantly correlated with AVP excretion in 24hr-urine in normal subjects. In 25 patients with neurogenic diabetes insipidus diagnosed by hypertonic saline infusion test, the AVP concentration in random urine was less than 13 pg/mg Cr. In approximately 1% of the normal subjects the urinary AVP level was below this range. Therefore, more intensive examinations should be planned to rule out the failure of AVP secretion in the case of such low AVP level in random urine. We also investigated the physiological changes in AVP secretion in 815 children and 352 pregnant women by measurement of urinary AVP. Even a large number of samples could be measured using this simple procedure.

Adolescent↗
PubMed1991

Amino acid sequence of 10-kDa protein in photosystem I reaction-center complex from a thermophilic cyanobacterium, Synechococcus elongatus Naegeli.

Four small subunits (14, 13, 10, and 8 kDa) of the photosystem I reaction-center complex were isolated from a thermophilic cyanobacterium Synechococcus elongatus. The complete amino acid sequence of the 10-kDa subunit was determined to consist of 80 amino acid residues giving a molecular mass of 8855.3, excluding iron and sulfur atoms, and containing two special sequences of cysteine residues, Cys-X-X-Cys-X-X-Cys-X-X-X-Cys-Pro, at residues 10-21 and 47-58, which indicates that the subunit is an apoprotein carrying two iron-sulfur centers, FA and FB, assigned as [4Fe-4S] clusters. The amino acid sequence indicated an 87.5% identity compared with those deduced from the nucleotide sequences of chloroplast gene psa C from several plants.

Amino Acid Sequence↗
PubMed1991

[The treatment of condyle neck fracture: statistics gathered by multi centric study and the related prognosis].

There are two different treatments for condyle neck fracture. One is non-surgical treatment involving intermaxillary fixation, and the other is radical surgical treatment through various techniques, but it is difficult to discuss the relative merits. The purpose of this report is to decide whether surgical treatment is necessary, by comparing the two types of treatment. In the period between April 1981 to December 1987, we treated 136 cases of condyle neck fracture at the Second Department of Oral and Maxillofacial Surgery School of Dentistry Aichigakuin University, and in 18 nearby hospitals. Of the 136 cases, 58 cases had fracture only at the condyle neck, while 78 cases had some concomittant fracture. As regards treatment, of the 136 cases, 49 (36%) were treated surgically, while 87 (64%) were treated non-surgically for condyle neck fracture. The surgically treated cases were divided into three groups: 24 cases were treated by pinning, 16 cases were treated by inter osseous wiring, and there were 9 other cases. In the treatment of concomittant fracture, 38 cases involved inter osseous wiring, 22 cases involved metal plate fixations, and there were 4 other cases. Non-surgical treatment accounted for 15 cases. The rate of surgical treatment for concomittant fracture was 82.1% of the cases treated. In surgically treated cases of condyle neck fracture, the mouth opening prognosis was generally poor. However, in these cases the deviation of mouth opening was generally better than in non-surgically treated cases. There were no differences in mastication, occlusion and pain in the TMJ region.

Bone Wires↗
PubMed1991

[Utility and limitation of sequential saphenous vein graft for complete revascularization in coronary artery surgery].

Multiple bypass grafting in complete myocardial revascularization requires frequently the use of sequential saphenous vein grafts as well as arterial grafts. To expect the favorable good clinical results of revascularization, therefore, refined surgical technique for saphenous vein grafting and proper selection of suitable coronary arteries for bypass are important. Between January 1989 and April 1990, 91 patients underwent CABG utilizing internal thoracic arteries (ITA) in 79% and SVG in 99% of the patients with an average of 3.3 anastomoses per patients. Postoperative angiography was performed 4 or 8 weeks after surgery. Early patency rates were 92% (204/221) in overall anastomotic sites, 96% (52/54) in ITA and 91% (152/167) in SVG respectively. There was no difference in patency rates between individual (90%) and sequential (92%) grafts. In sequential grafting, however, patency rate of side-to-side anastomosis was higher than that of end-to-side anastomosis. Patency rates of the grafts were also evaluated in terms of the sizes of coronary arteries and intraoperative graft flows. These studies lead to the following conclusions: In individual grafting, the acceptable patency rate can be expected when the graft flow exceeds 30 ml/min even if the internal diameter of coronary artery is less than 1.5 mm. In sequential grafting, on the other hand, a diameter more than 1.5 mm is desirable for the coronary artery at the site of end-to-side anastomosis.

Adult↗
PubMed1990

Endothelin-1 and platelet activating factor stimulate thromboxane A2 biosynthesis in rat vascular smooth muscle cells.

The effect of endothelin-1 (ET-1) on the release of thromboxane A2 (TXA2) was examined in cultured rat vascular smooth muscle cells (VSMC). ET-1 (10(-11) to 10(-6) M) significantly stimulated the release of thromboxane B2 (TXB2), a stable metabolite of TXA2. These effects of ET-1 were blocked by a cyclooxygenase inhibitor (indomethacin), a TXA2 synthetase inhibitor (CV-1451) and a specific platelet activating factor (PAF) antagonist (CV-6209). Additionally, PAF (10(-11) to 10(-6) M) stimulated the TXB2 release. Pretreatment with the phospholipase A2 inhibitor dexamethasone potently inhibited both ET-1 and PAF-induced elevation of cytosolic free Ca2+ concentrations [( Ca2+]i) in fura-2-loaded VSMC. These results clearly demonstrate that both ET-1 and PAF stimulate TXA2 biosynthesis in cultured rat VSMC, and TXA2 may contribute to the elevation of [Ca2+]i induced by ET-1 or PAF in VSMC. Furthermore, the stimulation of TXA2 biosynthesis may be a result of PLA2 activation by not only ET-1 but also PAF.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Effect of granulocyte colony-stimulating factor on neutropenia due to chemotherapy for non-Hodgkin's lymphoma.

The authors administered recombinant human granulocyte colony-stimulating factor (rhG-CSF) to 16 patients with advanced non-Hodgkin's lymphoma treated with combination chemotherapy. Groups of three to five patients were treated with 50, 100, 200, and 400 micrograms/m2 per day of rhG-CSF by intravenous infusion for 14 days, beginning 3 days after chemotherapy. There was a strong linear relationship between the dose and the area under the curve over this dose range. The rhG-CSF was rapidly cleared from serum, with a mean half-life of 5.97 hours for the second phase (t1/2). In patients treated with a dose of more than 100 micrograms/m2 per day, the duration of neutropenia (P less than 0.01) and the duration of fever (P less than 0.05) were significantly decreased. The rhG-CSF was well tolerated and the only clinical observation that appeared relating to rhG-CSF administration was slight bone pain. This study strongly suggests that an optimum dose of rhG-CSF in patients after chemotherapy is 100 to 200 micrograms/m2. Our study shows that rhG-CSF is a clinically useful drug for patients treated with myelosuppressive chemotherapy.

Adult↗