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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 649 records · Page 36Linked to original sources
PubMed1989

Absent effect of plasma vasopressin on rat brain blood flow during hemorrhage.

We investigated whether a reflex increase in plasma vasopressin level due to hemorrhagic hypotension affects brain blood flow. In 60 lightly anesthetized, artificially ventilated rats, the flow was determined with radiolabeled microspheres. We found excellent maintenance of blood flow throughout all brain regions during the hypotensive state (71 mmHg on average), and such maintenance of flow was not modulated at all by a supramaximal intravenous dose of the selective vasopressin V1-receptor antagonist [d(CH2)5 Tyr-(Me)]AVP. The latter finding also implies that the V1 antagonist failed to unmask the vasodilator type actions of V2 receptors on the maintenance of flow during hemorrhagic hypotension. These were true also when the cervical sympathetic bundles were severed bilaterally. The plasma level of endogenous vasopressin was increased during hypotension, ranging from 118 to 973 pg/ml. Despite this increase, the brain blood flow was entirely independent of the plasma vasopressin level in all the brain regions studied. We conclude that the brain circulation of rats can maintain its blood flow during hemorrhagic hypotension without any apparent contribution from a concomitant reflex increase in plasma vasopressin. Despite our negative results for the brain blood flow, the possible segmental effects of circulating vasopressin on the brain arterial caliber remain to be clarified under conditions of hemorrhagic hypotension.

Animals↗
PubMed1989

Modulation of plasma exudation by PGE2 and that of leukocyte migration by LTB4 in inflammatory models.

Des-Phe8-Arg9-BK could be detected in the entire course of rat carrageenin pleurisy up to 24 h, together with a reduction of the residual levels of high molecular weight kininogen and prekallikrein. On the basis of this continuous release of bradikinin, prostaglandin E2 was released up to 5 h in the pleural exudate and enhanced the plasma leakage. In rat cardiac infarction, the initial increase in the number of polymorphonuclear leukocytes in the cardiac tissue was accompanied by leukotriene B4 in the tissue and this was followed by the second increase and activation of the complement system.

Animals↗
PubMed1989

Aspirin lowers blood pressure in patients with renovascular hypertension.

To clarify the role of renal prostanoid in hyperreninemia and high blood pressure in human renovascular hypertension, we measured prostaglandin E2 and renin activity in renal venous and abdominal aortic plasma before and after the intravenous administration of the cyclooxygenase inhibitor, aspirin DL-lysine. Subjects were six patients with unilateral renovascular hypertension and six with essential hypertension. In patients with renovascular hypertension, prostaglandin E2 concentration in renal venous plasma from the stenotic kidney was 9.25 +/- 1.48 pg/ml, which was significantly higher (p less than 0.01) than the concentration in the renal venous plasma from the normal kidney (4.97 +/- 1.02 pg/ml) or in the aortic plasma (2.59 +/- 0.15 pg/ml). Plasma renin activity was also higher in the renal vein of the stenotic kidney than in the other two sites. The stenotic side/normal side ratio of the renal venous prostaglandin E2 correlated significantly with a renin ratio greater than 1.5 (r = 0.8211, p less than 0.05). Intravenous injection of aspirin DL-lysine (18 mg/kg) 30 minutes later markedly suppressed prostaglandin E2 and renin levels at all sites and clearly lowered arterial blood pressure (mean: from 120 +/- 6 to 110 +/- 5 mm Hg, p less than 0.01). The reduction in blood pressure correlated significantly with the suppression of plasma renin activity in the aorta (p less than 0.05) and in the renal vein of the stenotic kidney (p less than 0.01). Conversely, in patients with essential hypertension, aspirin had little effect on renin levels and increased mean blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Forskolin activates voltage-dependent Ca2+ channels in bovine but not in rat fasciculata cells.

The action of forskolin on bovine and rat fasciculata cells was examined in freshly prepared cells. Bovine cells show a close parallelism between production of steroids and production of cAMP as a function of the concentration of ACTH up to 10(-8) M. By contrast, forskolin (10(-7)-10(-5) M) causes a similar increase in steroid synthesis but relatively little effect on the production of cAMP. cAMP-dependent protein kinase shows a similar response to ACTH but no response to forskolin in the same range of concentrations. ACTH and forskolin, at submaximal concentrations, cause greater steroid production when added together than when added separately, but the two agents at high concentrations produce the same response whether added together or separately. The inhibitors of voltage-dependent Ca2+ channels inhibit the steroidogenic response to forskolin (IC50 for nifedipine is 0.1 microM and for Py108-068 is 0.4 microM). A Ca2+ channel agonist (BAY K8644) increases the steroidogenic response of bovine adrenal cells to forskolin, but not that of ACTH. Finally, forskolin causes a concentration-dependent uptake of Ca2+ by these cells; in the concentration range of 0.1-10 microM, forskolin caused an increase in [Ca2+] from 185 nM to 345 nM. By contrast, forskolin caused some stimulation of the production of cAMP, but not that of steroids in rat fasciculata cells. It is concluded that in bovine fasciculata cells forskolin activates voltage-dependent Ca2+ channels with a consequent increase in steroid synthesis. This effect is independent of the well known action of forskolin on adenylate cyclase. Rat fasciculata cells, on the other hand, do not possess such Ca2+ channels and do not show a steroidogenic response to forskolin.

Adenylyl Cyclase Inhibitors↗
PubMed1989

Diazepam potentiates the corticoidogenic response of bovine adrenal fasciculata cells to dibutyryl cyclic AMP.

To provide a possible role of peripheral type benzodiazepine receptors in the regulation of glucocorticoid biosynthesis. We have examined the effect of diazepam on the corticoidogenic response to dibutyryl cyclic AMP in isolated bovine adrenal fasciculata cells. Diazepam alone (up to 100 microM) had no effect on the corticoidogenesis. Diazepam caused a dose-dependent potentiation of dibutyryl cyclic AMP-induced corticoidogenesis. However, diazepam had no effect on the corticoidogenic response to ACTH and a high concentration of KCl. The potentiating effect by diazepam was clearly detected after 90 min-incubation, and it was blocked by YM-684 (diazepam antagonist) and ML-236B (cholesterol de novo synthesis inhibitor). Diazepam caused no significant decrease of intracellular content of cholesteryl esters during the corticoidogenic response to dibutyryl cyclic AMP. When the cells were incubated in the presence of (+)-PN200-110, a potent voltage-dependent Ca channel inhibitor, the potentiating effect by diazepam was not affected in spite of a significant inhibition of dibutyryl cyclic AMP-induced corticoidogenesis. These results indicate that the potentiating effect of diazepam on dibutyryl cyclic AMP-induced corticoidogenesis is due in part to the activation of the intracellular cholesterol supply system (cholesterol de novo synthesis) without any change of voltage-dependent Ca channels.

Adrenal Cortex↗
PubMed1989

[Treatment with a new preparation using peplomycin emulsion in hydroxypropylcellulosum. Analysis of immediate response in sixty-two patients with bladder cancer].

To 62 vesical tumor patients, 30 ml of a HPC-PEP mixed solution was infused into the urinary bladder. The HPC-PEP solution was prepared by adding 15 ml of 2% hydroxypropylcellulosum (HPC) to 15 ml of peplomycin (PEP)/physiological saline solution in which 90 mg PEP had been dissolved. Accordingly, a total of 30 ml of the mixed solution was used. On day 7 after treatment, a clinical evaluation was made through endoscopic observation and urine cytodiagnosis. The results of the evaluation were expressed by assigning appropriate grades for the improvements made. As for the overall clinical effects, 10 patients demonstrated excellent improvement (CR) but 26 patients exhibited no improvement (NC). The overall clinical efficacy for all cases was 58%. When the evaluation was made according to severity (T1, T2, or T3), the results were as follows: of 43 T1 patients, 9 patients were judged CR, and 23 patients were PR; and of 15 T2 patients, 1 patient was CR and 3 patients were PR. However, all T3 patients were NC. The clinical efficacy for the T1 and T2 groups was 74.4% and 26.4%, respectively. A significant difference was observed between the T1 group and the T2 and T3 groups (p less than 0.05). Evaluation made according to the degree of histopathological differentiation (G1, G2 and G3) demonstrated the following results: of 23 G1 cases, 6 cases were CR, 9 cases were PR; of 32 G2 cases, 4 cases were CR and 16 cases were PR; and of 7 G3 cases, only 1 patient was found to be PR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Effects of the intracerebroventricular atrial natriuretic factor on angiotensin II or sodium-induced blood pressure elevation and natriuresis.

We examined the effects of intracerebroventricular (i.c.v.) administration of atrial natriuretic factor (ANF) on pressor and natriuretic responses induced by i.c.v. angiotensin II (Ang II) or hypertonic NaCl in conscious male Wistar rats. The i.c.v. artificial cerebrospinal fluid (CSF) or ANF alone did not cause recognizable changes in mean blood pressure (MBP), urinary volume (UV), or sodium excretion (UNaV). The i.c.v. Ang II or 0.6 M NaCl raised MBP, decreased UV, and increased UNaV. When ANF was administered with Ang II, the Ang II-induced changes in MBP, UV, and UNaV were diminished significantly. ANF also opposed the effects of 0.6 m NaCl, though the effect was significant only in the case of blood pressure. Our results indicate that brain ANF may have antipressor and anti-natriuretic roles.

Angiotensin II↗
PubMed1989

Changes in rat submandibular gland N-acetyl-beta-glucosaminidase activity in streptozotocin-induced diabetes.

Changes were determined in the activity of submandibular gland N-acetyl-beta-glucosaminidase from streptozotocin-induced diabetic and insulin-treated rats. Most of the activity of this enzyme was localized histochemically in the ductal cells. The activities of this enzyme from both the subcellular supernatant and lysosomal fractions were increased in the diabetic group, and recovered to the level of the controls in the insulin-treated group. Although sex differences were observed in the activity of this enzyme, with the activity in the male rats of the control group being lower than that in the females, these differences disappeared in the diabetic group, suggesting that insulin may be related to the expression of androgen function. Both enzymes in the supernatant and lysosomal fractions were separated by isoelectric focusing into two enzymatic proteins with isoelectric points in the vicinities of pI 3 and pI 8. The effects of diabetes were reflected in an increase primarily in the activity in the vicinity of the pI 8 isoenzyme in the supernatant fraction, and in an increase in both isoenzymes in the lysosomal fraction. It is clear from these findings that the diabetic condition brings about an insulin-dependent increase in the activity of N-acetyl-beta-glucosaminidase in the rat submandibular gland, and imparts certain changes in the properties of the enzymatic proteins themselves.

Animals↗
PubMed1989

[Tracheobronchial reconstruction of malignant tumors].

To August, 1988, we performed tracheobronchial reconstruction for 159 patients with malignant tumors. Operative methods in these patients and the operative results studied in the end of March, 1989, was reported. As for adenoid cystic carcinoma, we stressed, by illustrating cases, that postoperative radiation therapy was useful and that it should be given for all patients with this disease. About one half of patients with thyroid carcinoma infiltrating the trachea died of symptoms related with tracheal stenosis. However, tracheobronchial reconstruction improved 10 year survival rate in patients with advanced thyroid carcinoma remarkably, which became close to that in patients with non-infiltrating thyroid carcinoma. As for lung cancer, tracheobronchial reconstruction had good indication for squamous cell carcinoma.

Adult↗
PubMed1989

[New classification and analysis of lung sounds].

Recently, classification and nomenclature of lung sounds has been changed from assessment based on subjective interpretation to assessment based on objective, measureable criteria related to mechanisms of sound generation. The adventitious sounds was classified to four kinds of principal terms, continuous adventitious sounds (wheezes, rhonchi) and discontinuous adventitious sounds (coarse crackles, fine crackle) at the 1985 International Symposium on Lung Auscultation. Lung sounds in the surgical patients were digitized for the analysis of both the time domain and the frequency domain which had been recorded by tape recorder. Rhonchi, fine crackle and tracheal stenotic sounds were characterized by the analysis of the frequency domain. Lung sound analysis is promising because it is safe, non invasive and may be used for clinical studies in the surgical patients.

Humans↗
PubMed1989

[Clinical reevaluation of aztreonam (AZT) on urinary tract infections].

The clinical effectiveness and safety of Aztreonam (AZT) were studied in 55 patients with complicated urinary tract infections. AZT was administered at a dose of 4 g/day for 5 days. The results as evaluated by the UTI criteria were excellent in 8 cases, moderate in 26 and poor in 21. The overall effectiveness rate was 61.8%. Out of 64 strains of bacteria isolated before treatment, 50 strains (78.0%) were eradicated by the treatment. Bacteriological eradication rates for gram negative rods and gram positive cocci were 79.6% and 66.7%, respectively. There were no obvious side effects, except for a temporary elevation of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase alkalinephosphatase, and total bilirubin in some patients. The results indicate that AZT tablets are useful and safe for the treatment of complicated urinary tract infections.

Adolescent↗
PubMed1989

[Non-verbal facial and topographic visual object agnosia--a problem of familiarity in prosopagnosia and topographic disorientation].

In recent years, prosopagnosia is defined as the "loss of ability to recognize the well-acquainted persons like the family members by their physiognomy." There are many reports based on this definition. However, from the viewpoint of symptomatology, there are many problems not entirely solved yet. And the mechanism of its manifestation is not clearly explained. Topographic disorientation, which often accompanies prosopagnosia, is studied even less. From the results of the postmortem examination in the literature, bilateral occipito-temporal lesions have been known to cause prosopagnosia. However, the recent radiographical examination by the computed tomography revealed that the prosopagnosia is also caused by the right occipito-temporal lesions only. We experienced a case with prosopagnosia and topographic disorientation which were considered to be caused by infarction in the territory of the right posterior cerebral artery. Detailed symptomatological, morphological and functional examinations were carried out by means of various psychological testing, X-ray computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET). The patient was a 70-year-old right-handed man who suffered from sudden visual loss on both eyes, and was admitted to our hospital after four weeks. On examination, a decrease of visual acuity and right homonymous hemianopsia were recognized. When visual acuity was recovered, he was unable to recognize the faces of his relatives and friends, with whom he has been well acquainted for many years. He also found his own house, the buildings and streets around it as entirely unfamiliar. Seven months after the onset of the disease, examination showed he had definite prosopagnosia and topographic disorientation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

[Antemortem diagnosis of Marchiafava-Bignami disease].

Marchiafava-Bignami disease (M-B disease) is a peculiar disease, observed in hardened drinkers and resulting in demyelinization and necrosis of the corpus callosum. The clinical symptoms are diverse, and it is difficult to diagnose accurately while the patient is alive. Almost all reports in the past have been based on necropsy. Only three cases of M-B disease have been reported in Japan so far, none of which was based on a diagnosis while the patient was alive. We have been able to perform diagnosis of M-B disease while the patients were still alive by means of X-ray computed tomography (CT) and magnetic resonance imaging (MRI), and to study the clinical symptoms from the acute stage. In addition to the study on our own patients, we also conducted a neurosymptomatic study on the clinical symptoms of 6 cases, for which details of the symptomatology have been described-out of about 150 cases reported in the past. In the acute stage of M-B disease, we observed psychic symptoms, such as clouding of consciousness, mnemonic disorders and disorders and disorientation, or various frontal lobe symptoms, such as change in personality, raptus nervorum, dysphemia, pyramidal signs and astasia-abasia. These are non-specific symptoms and it is necessary to differentiate from encephalitis and other encephalopathy. In the chronic stage, dysphemia becomes sustained and, in addition, symptoms of transection of the corpus callosum are noted among the disorders of higher cerebral functions. If M-B disease is suggested from clinical symptoms, it is advisable to confirm the lesions in the corpus callosum by X-ray CT and MRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗