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Biomedical subjects

H Kurihara

Publications and source records attributed to H Kurihara.

At least 325 records · Page 18Linked to original sources
PubMed1989

Cell surface protein antigen from Wolinella recta ATCC 33238T.

A high-molecular-weight (approximately 150,000) protein was selectively isolated by acid extraction from the cell surface of Wolinella recta and purified by negative adsorption on DEAE-cellulose and gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that this protein was found in W. recta but not in other Wolinella species, such as W. curva and W. succinogenes. Sera from patients with periodontitis reacted strongly with this protein antigen, whereas sera from healthy donors showed little or no reactivity, as determined by immunoblotting analysis. In serum, titers of immunoglobulin G antibodies to the protein antigen were significantly higher in patients with periodontitis than in periodontally healthy donors, as detected by an enzyme-linked immunosorbent assay.

Antigens, Bacterial↗
PubMed1989

Central effect of endothelin on blood pressure in conscious rats.

This study was conducted to investigate the effect of intracerebroventricular administration of endothelin (EDT), a novel potent vasoconstricting peptide, on blood pressure in conscious rats. The lateral cerebral ventricle of male Wistar rats was cannulated, and the femoral artery was also cannulated to measure the mean arterial blood pressure (MABP) and heart rate (HR). EDT dissolved in 10 microliters of artificial cerebrospinal fluid (ACSF) (8.25-66 pmol icv) provoked a dose-dependent increase in MABP. EDT also increased HR, although the effect of 66 pmol was variable. Intracerebroventricular ACSF did not provoke any effects on MABP and HR. Intracerebroventricular EDT also provoked contralateral rotational behavior. Pretreatment with 2 mg/kg iv phenoxybenzamine significantly suppressed the 16.5 pmol icv EDT-induced increase in MABP. Moreover, 16.5 pmol icv EDT markedly increased plasma epinephrine and norepinephrine concentration. These results indicate that EDT has a central pressor action, and the action might be mediated, at least in part, by catecholamine release to the periphery. EDT might play a role in the central control of blood pressure, although the physiological implications have not yet been determined.

Animals↗
PubMed1989

Studies on orally active cephalosporin esters. III. Effect of the 3-substituent on the chemical stability of pivaloyloxymethyl esters in phosphate buffer solution.

The effect of substituents at the C-3 position on the degradation kinetics of the pivaloyloxymethyl (POM) ester of delta 3 cephalosporin in phosphate buffer solution (pH 6-8) was investigated. In the degradation, the isomerization process to the delta 2 ester was the rate-determining step. In this study, the logarithm of the isomerization rate to the delta 2 ester (log k12) correlated with the carbon-13 nuclear magnetic resonance chemical shift difference value at C-3 and C-4 of the delta 3 ester (delta delta (4-3)). The energy level of the lowest unoccupied molecular orbital (LUMO) of the delta 3 esters also correlated with log k12. The electronic properties at the C-2 position had no effect on the isomerization reaction. On the other hand, the logarithm of the isomerization rate back to the delta 3 ester (log k21) correlated with the van der Waals volume (MV) of the 3-substituent. These results show that the substituent at the C-3 position influences mainly the electronic structure of the conjugated pi-bond system (C3 = C4 - C4 = O) and consequently affects the feasibility of isomerization to the delta 2 ester, i.e., the stability to degradation.

Administration, Oral↗
PubMed1989

[Multiple myeloma manifesting as a solitary cranial tumor. Case report].

A 76-year-old female struck her head in the parietal region and noticed a soft scalp mass. Approximately 3 months later, the mass was enlarged and she was evaluated at a local hospital. Although the tentative diagnosis was old subcutaneous hematoma, incision of the scalp revealed not hematoma but rather a tissue and bony defect. On admission to the authors' institution, she was found to have a round, smooth, subcutaneous mass in the upper left parietal region. The tumor was about 5 cm in diameter and 4 cm in height, and was soft, nonpainful, and pulsatile. Plain X-rays revealed an osteolytic lesion in the left parietal bone. Computed tomography demonstrated a high-density lesion corresponding to the bony defect, which was homogeneously enhanced by contrast material. Left external carotid angiography showed the mass to be vascular, its main feeder being the middle meningeal artery. It was concluded that the tumor originated from the diploë. The tumor was subtotally removed, and histopathological examination showed it to be a plasmacytoma. Laboratory tests, including protein electrophoresis, disclosed hypergammaglobulinemia with M-spikes. Immunoelectrophoresis demonstrated a serum paraprotein of immunoglobulin G kappa specificity. Multiple myeloma diffusely involving bone is well known, but a soft mass alone with a bony defect in the cranial vault is very rare. The clinical features and treatment of silent, solitary masses associated with multiple myeloma are discussed.

Aged↗
PubMed1989

Pharmacological effect of endothelin, an endothelium-derived vasoconstrictive peptide, on canine basilar arteries.

The purpose of this study was to evaluate the constrictive effect of endothelin, a peptide vasoconstrictor derived from endothelium, on canine basilar artery. Constriction was measured by an isometric tension recording method. Endothelin induced prolonged contraction of canine basilar artery in a dose-dependent fashion, the estimated concentration at 50% contraction being (2.1 +/- 0.5) X 10(-9) M (mean +/- SEM). Removal of endothelium significantly augmented the arterial response to endothelin. In Ca(++)-free medium no contractile response was elicited at 10(-8) M endothelin. Papaverine (10(-4) M) and nicardipine (10(-8) M), a calcium channel blocker, almost completely inhibited the contraction induced by 10(-8) M endothelin. Pretreatment with nicardipine (10(-8) - 10(-6) M) also significantly suppressed the response to endothelin. Acetylcholine (10(-7) - 10(-4) M), adenosine triphosphate (10(-7) - 10(-5) M), and thrombin (0.1 and 1.0 U/ml) dose-dependently inhibited contraction of canine basilar artery in response to 3 X 10(-9) M endothelin. These results show that endothelin has a potent constrictive effect on canine basilar artery and suggest that this substance may play an important role in the pathogenesis of vasospasm following subarachnoid hemorrhage.

Adenosine Triphosphate↗
PubMed1989

[The relationship between mitral regurgitation and asynergy of the left ventricle in old myocardial infarction].

To elucidate the mechanism of mitral regurgitation (MR) in patients with old myocardial infarction, two-dimensional (2D) and 2D Doppler echocardiographic examinations were performed in 92 patients. According to the sites of asynergy in the short-axis view of the left ventricle at the papillary muscle level, the patients were classified in three groups; i.e., anteroseptal (AS) group (49 cases), inferoposterior (IP) group (29 cases), and the AS + IP group (14 cases). The existence and severity of MR were evaluated by 2D Doppler echocardiography and the presence of mitral valve prolapse (MPV), by 2D echocardiography. The mitral valve ring diameter was also measured. The incidence of MR was significantly higher in the IP group (41%) and AS + IP group (43%) than in the AS group (20%) (p less than 0.05, respectively). In the IP group, 21 patients had left ventricular asynergy at the base of the posterior papillary muscle; eight did not. In the former 21 patients with asynergy, MR was detected in 12 (57%) and MVP in nine (43%), whereas neither MR nor MVP was detected in the eight patients without asynergy. The grade of MR assessed by 2-D Doppler echocardiography was significantly more severe in patients with MVP than in those without MVP (MR distance: 23 +/- 6 mm with MVP vs 11 +/- 1 mm without MVP; p less than 0.05, MR area; 312 +/- 217 mm2 with MVP vs 64 +/- 29 mm2 without MVP; p less than 0.05). MR appeared at the mitral orifice between its middle portion and the posteromedial commissure, which coincided with the site of MVP in the majority of cases. In the AS and AS + IP groups, however, such close relationships between MR and MVP were absent. In these groups, mitral valve ring diameters were significantly larger in patients with MR than in those without MR (AS group: 32 +/- 3 mm with MR vs 24 +/- 2 mm without MR; p less than 0.01, IP group: 26 +/- 2 mm with MR vs 25 +/- 2 mm without MR; NS, AS + IP group: 30 +/- 3 mm with MR vs 24 +/- 1 mm without MR; p less than 0.05). Mitral valve ring diameters in the IP group with MR (26 +/- 2 mm) were smaller than in those in the AS and AS + IP groups with MR, and did not differ from those in the IP group without MR (25 +/- 2 mm). In conclusion, posterior papillary muscle dysfunction was mainly responsible for MR in the inferoposterior infarction and the dilatation of the mitral valve ring in the infarction involving the anteroseptal wall.

Aged↗
PubMed1989

[Brain abscess following intracerebral hematoma].

A 53-year-old man fully conscious was admitted with lt. hemiparesis due to a rt. putaminal hemorrhage. A phlebitis of superficial vein at lt. leg was noted on the 7th hospital day. Following administration of antibiotics, he was afebrile three days after. But local inflammation of phlebitis and leukocytosis continued for over one week. He had no sign of infection thereafter. Four months later, the hemiparesis exacerbated. CT scan revealed a cystic lesion with ring-like enhancement at the site of the hematoma. He was afebrile and had no sign of meningeal irritation. The patient underwent a stereotaxic aspiration of brown turbid pus. The culture from the aspirate was positive for staphylococcus, and histopathological examination of the excised specimen demonstrated a brain abscess with hemosiderin deposits. Follow-up CT scan revealed a progressive diminution in the size of the abs cess. We felt the hematoma represented an area of locus minoris resistentiae and that bacterial seeding of the hematoma from phlebitis resulted in brain abscess formation. Brain abscess formation should be considered as having possibly developed in patients with clinical deterioration after cerebral vascular disease.

Basal Ganglia Diseases↗
PubMed1988

Endothelin stimulates c-fos and c-myc expression and proliferation of vascular smooth muscle cells.

Recently, a potent vasoconstrictor peptide, endothelin (EDT), was isolated from vascular endothelial cells. We examined its effect on rat vascular smooth muscle cells (VSMCs). EDT induced the elevation of intracellular calcium, which was dependent on extracellular calcium and inhibited by a calcium-channel antagonist in a competitive manner. EDT caused a rapid and transient increase in the c-fos and c-myc mRNA levels and stimulated the DNA synthesis of VSMCs in a dose-dependent manner. This effect of EDT on the proliferation of VSMCs might be related to the development of atherosclerosis.

Animals↗
PubMed1988

A novel potent vasoconstrictor peptide produced by vascular endothelial cells.

An endothelium-derived 21-residue vasoconstrictor peptide, endothelin, has been isolated, and shown to be one of the most potent vasoconstrictors known. Cloning and sequencing of preproendothelin complementary DNA shows that mature endothelin is generated through an unusual proteolytic processing, and regional homologies to a group of neurotoxins suggest that endothelin is an endogenous modulator of voltage-dependent ion channels. Expression of the endothelin gene is regulated by several vasoactive agents, indicating the existence of a novel cardiovascular control system.

Amino Acid Sequence↗
PubMed1988

Identification of thromboxane A2 receptor in cultured vascular endothelial cells of rat aorta.

The binding site for [3H]SQ29,548, a potent and selective thromboxane A2 (TXA2) receptor antagonist, was studied in cultured vascular endothelial cells (VEC) of the rat aorta. Specific binding of [3H]SQ29,548 to rat VEC at 24 degrees C was saturable, displaceable and of high affinity. Scatchard analysis of equilibrium binding studies indicated that rat VEC contain a single class of binding sites with a Kd of 2.7 nM. The number of maximum binding sites (25.8 fmol/10(6) cells) for [3H]SQ29,548 on rat VEC was respectively 23 and 3.2 times more than that on rat platelets and rat vascular smooth muscle cells. Four TXA2 receptor antagonists and U46619 completely suppressed [3H]SQ29,548 binding to rat VEC, whereas other prostanoids, such as PGD2, PGF2 alpha, PGE1 and Iloprost, displaced the ligand binding only at considerably higher concentrations. These results suggest that the specific receptor for TXA2 is present in rat vascular endothelial cells.

Animals↗
PubMed1988

A novel peptide vasoconstrictor, endothelin, is produced by vascular endothelium and modulates smooth muscle Ca2+ channels.

Since the discovery of endothelium-dependent vasodilation, vascular endothelium has been recognized as an important functional unit contributing to the regulation of vascular tonus. Recent purification, structure determination and molecular cloning of a novel peptidergic vasoconstrictor, endothelin, from the culture supernatant of porcine aortic endothelial cells has further substantiated this concept. Starting from a large quantity of serum-fee endothelial cell-conditioned medium, endothelin was purified to homogeneity after three steps of high performance liquid chromatography by collecting active fractions and constricting porcine coronary artery strips. A peptide sequence analysis showed that endothelin was a previously unknown 21-residue peptide with two intrachain disulphide bonds. The EC50 of endothelin for contraction of porcine coronary artery was 4.0 x 10(-10) mol/l, indicating that endothelin is one of the most potent vasoconstrictors known. The pharmacological and structural properties of endothelin suggest that the peptide acts by activating voltage-dependent Ca2+ channels in vascular smooth muscle cells. Cloning and sequence analysis of complementary (c)DNA encoding porcine and human endothelin precursors showed that endothelin was produced de novo in endothelial cells from an approximately 200-residue prepropeptide through an unusual proteolytic processing by a putative 'endothelin-converting enzyme'. Northern blot analysis showed that preproendothelin messenger (m)RNA was expressed not only in cultured endothelial cells but also in fresh intimal tissue from porcine aorta, and that mRNA can be induced markedly in response to several vasoactive agents in cultured endothelial cells, suggesting the existence of a novel endothelium-mediated cardiovascular control system.

Animals↗
PubMed1988

[Surgical treatment and result of high aortic occlusion].

Twenty-one patients with high aortic occlusion treated at our institution from 1967 to 1986 were reviewed. There were seventeen men aged from 39 to 78 (mean age: 61.0) underwent surgical intervention. All patients presented clinical manifestations of vascular insufficiency of the lower limbs; rest pain in eleven patients, intermittent claudication in nine and the others. Sexual impotence was present in eight patients. Renal artery involvement was seen in one case, and renovascular hypertension was observed in this patient. Hypertension and ischemic heart disease were present in twelve cases, cerebrovascular insufficiency in one case, diabetes mellitus in three cases. The following surgical treatments were performed; end-to-end Y-shaped Dacron graft implantations from the infrarenal abdominal aorta to the common femoral arteries in six patients, onlay V-shaped Dacron graft implantations in three patients, axillofemoral extra-anatomic bypass in four patients, and amputation only in one. The hospital mortality was 18% (3/17). Twelve patients discharged from the hospital are followed up (average period was 118 months), but the follow up was lost in two patients. There were two late deaths, which course was not related to operations. The prognosis of high aortic occlusion after anatomic bypass is good, thus it was concluded that anatomic bypass with Y-shaped or V-shaped Dacron graft was recommended and extra-anatomic bypass might be performed only in a high risk patient.

Adult↗
PubMed1988

[A review of post-operative multiple organ failure in peripheral arterial diseases].

Two-hundred- and-fifty-one patients of peripheral arterial diseases underwent 281 operations for past 11 years in our institute, and multiple organ failure (MOF) occurred in 10 patients (4.0%). These patients were reviewed and were compared with in other diseases. Survival rate was 50% and all the patients with 4 or more organ disorders died. Incidence and survival rate were not significantly different from operative time, blood loss and blood transfusion. Significant difference was observed between elective operation (3.0%) and emergent operation (20.0%). Compared with other diseases, MOF occurred more rarely in peripheral arterial diseases than in aortic aneurysms, but occurred 1.4 times of digestive diseases. While the gastro-intestinal bleeding as the initial failure organ occurred more frequently in peripheral arterial diseases than in other diseases, heart and respiratory failures were rare. MOF occurred after peripheral arterial intervention as well as other abdominal and thoracic surgery. To avoid MOF it is important to avoid MOF that the emergent surgery should be kept out and that general status, especially the grade of diabetes mellitus should be evaluated sufficiently.

Adult↗
PubMed1988

[Clinical efficacy of mecobalamin in the treatment of oligozoospermia--results of double-blind comparative clinical study].

The clinical efficacy of mecobalamin in the treatment of male infertility was investigated by means of a multicenter collaborative study with 25 participating institutions. The study was carried out as a double-blind, comparative trial using three administration groups: 6,000 micrograms of mecobalamin per day, 1,500 micrograms of mecobalamin per day and a placebo group for 12 wk. The following results were obtained. 1. The total number of evaluated subjects was 375, consisting of 125 in the 6,000 micrograms/day mecobalamin group, 124 in the 1,500 micrograms/day mecobalamin group and 126 in the placebo group. There were no significant differences among the three administration groups in terms of the patient's background factors. 2. When all of the patients were analyzed, there were no statistically significant differences among the three administration groups in terms of the efficacy in relation to the sperm count or the motility rate. 3. However, it was decided to perform a more detailed analysis of the therapeutic efficacy in patients whose pretreatment sperm counts were 20 x 10(6)/ml or less. The reasons for this decision were two-fold: 1) There was a large degree of fluctuation in patients whose pretreatment sperm counts showed a mean value of more than 20 x 10(6)/ml for two or more determinations, and it was surmised that this fluctuation might have masked any therapeutic effect in those cases. 2) The WHO definition of oligozoospermia was recently decided as a sperm count of 20 x 10(6)/ml or less.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Sensitive method for determination of captopril in biological fluids by gas chromatography-mass spectrometry.

A sensitive method for the determination of captopril in blood and urine by gas chromatography-mass spectrometry is described. In order to prevent oxidative degradation of captopril, its sulph-hydryl group was immediately protected by treatment with N-ethylmaleimide (NEM), and the resulting NEM adduct was then converted into the bis(pentafluorobenzyl) derivative. Derivatized captopril was separated on a 2% OV-1 column, exhibiting a single peak of the correct theoretical shape. The detection limit was estimated to be 100 pg by using S-benzylcaptopril as an internal standard. The blood level and urinary excretion of unchanged captopril orally administered to dogs were determined by the proposed method. In addition, epimerization of the proline moiety and formation of the sulphoxide or sulphone through the esterification step are also described.

Captopril↗