Search PubMed⌕ Search

Biomedical subjects

M Mizuno

Publications and source records attributed to M Mizuno.

At least 451 records · Page 25Linked to original sources
PubMed1990

Hyperdynamic therapy for cerebral vasospasm.

The effects of hyperdynamic therapy on patients with cerebral vasospasm following subarachnoid hemorrhage (SAH), under normal blood pressure (BP) and normal blood volume conditions, are reported. Forty-four patients, who underwent surgery for aneurysms in acute stage, received hydroxyethyl starch (500 ml/day) postoperatively to prevent dehydration. Twenty-four of the 44 patients with prominent SAH on the computed tomographic (CT) scan, anticipating to develop cerebral ischemia due to vasospasm, were given dobutamine (DOB). The BP was maintained within the normal range, and the heart rate was kept below 130/min. In the 24 patients treated with DOB, cerebral blood flow (CBF) was measured repeatedly by the 133Xe intravenous injection method. In 8 of these 24 patients, the cardiovascular function was monitored with Swan-Ganz (S-G) catheters. Twelve of the 44 patients (27%) developed delayed neurological deficits associated with cerebral vasospasm. The neurological deficits were reversed by the administration of DOB, at a dose of 8-25 (average 12.4) micrograms/kg/min. In 43 patients, the ischemic lesions associated with vasospasm did not appear on CT scan and the patients were of normal condition at discharge. However, one patient showed multiple low-density lesions on CT scan. This was because of the failure of hyperdynamic therapy due to pulmonary complications. No case of pulmonary edema or heart failure due to volume overload was noted. In the 24 patients with prominent SAH, CBF increased significantly by up to 20% following DOB administration, although the BP stayed in the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Early surgery in elderly patients with ruptured intracranial aneurysms--preoperative clinical evaluation and prognosis.

Numerous clinical classification systems have been developed for patients with ruptured intracranial aneurysms. However, most systems do not take age into account and are less reliable in elderly than in younger patients in terms of indications for early surgery and predicting the clinical outcome. The authors have studied this problem using our clinical classification system and, present here the results of 38 elderly patients (greater than or equal to 65 years of age) who underwent neck clipping and implementation of continuous ventricular drainage within 3 days of aneurysm rupture. The clinical outcome at 1 year after onset was considered "good" if the patient was able to function independently and "poor" if he or she was partially or fully dependent or had died. The preoperative level of consciousness was not significantly correlated with the outcome according to Spearman's nonparametric statistical analysis. Age, however, was a significant factor: the incidence of poor outcome was significantly higher in patients over age of 70 years than in those between 65 and 70 (p less than 0.05). Postoperative complications, which were previously found to be significantly related to the outcome in elderly patients, were significantly more common in patients who had a history of cardiac, pulmonary, hepatic, and/or renal disease than in those without such a history (p less than 0.005). The authors found that the prognostic accuracy of clinical classification systems, based on preoperative level of consciousness, is improved in geriatric cases if one point is added for patients over age of 70 years or those with a history of systemic diseases. Additional relevant factors included computed tomographic findings and pre-existing cerebral dysfunction.

Aged↗
PubMed1990

[Significance of the PGI2 producing enzyme system in the pathogenesis of pregnancy-induced hypertension].

Characterization of the PGI2 producing enzyme system (P.E.S.) in pregnancy induced hypertension (PIH) was carried out by comparing its conversion from arachidonic acid (A.A.) or PGH2 to PGI2 using enzyme preparations from endothelial cells of the umbilical vein in normal pregnancy (N) and mild (M) and severe (S) types of PIH. 1) The conversion rate from A.A. to PGI2 in N was significantly (p less than 0.05) higher than in M and S. 2) The conversion rate from PGH2 to PGI2 in N was higher than in M and that in M was higher than in S. 3) The apparent Vmax values (nM/mg protein) (mean +/- S.E.M.) for P.E.S. in N (0.88 +/- 0.21) were significantly (p less than 0.05) lower than in M (2.76 +/- 0.71) and S (1.63 +/- 0.18). The apparent Km values (microM) (mean +/- S.E.M.) for P.E.S. in N (0.76 +/- 0.25) were significantly (p less than 0.05) higher than in M (0.29 +/- 0.07) and significantly (p less than 0.05) lower than in S (3.26 +/- 0.78). 4) The apparent Vmax values for PGI2 synthetase (P.S.) in N (0.44 +/- 0.09) and M (0.61 +/- 0.10) were significantly (p less than 0.05) higher than in S (0.11 +/- 0.06). The apparent Km values for P.S. in N, M and S were 0.12 +/- 0.07, 0.13 +/- 0.06 and 0.16 +/- 0.04, respectively. The present study showed that the symptoms in M may be kept from becoming aggravated by the production of large amounts of PGI2, due mainly to activation of cyclooxygenase, whereas progressive disorder of the regulation of blood pressure in S may be caused by low production of PGI2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Inhibitory effect of arachidonic acid on the synthesis of prolactin in human decidual tissues].

Much evidence indicates that human tissues produce prolactin. However, little is known as to which agents regulate its production in decidual tissues. Therefore, it is of interest to examine the effect of arachidonic acid on the production of prolactin, since it is present in considerably large amounts in decidual tissues. The addition of arachidonic acid to culture media resulted in a significant reduction in the amount of prolactin secreted from incubated decidual tissues in a dose-related fashion. Other poly-unsaturated fatty acids, i.e. linoleic and gamma-linolenic acid also inhibited its secretion, whereas saturated fatty acid and mono-unsaturated fatty acids, such as oleic acid, were without effect. The addition of phospholipase A2 and phospholipase C, enzymes to liberate arachidonic acid from phospholipids, also suppressed the secretion of prolactin. Indomethacin and BW-755C, inhibitors of cyclooxygenase and lipoxygenase, respectively, had essentially no effect on the secretion of prolactin. Translatable mRNA for prolactin was detected in decidual tissues. Arachidonic did not alter either the amount of mRNA in prolactin of the amount of its mRNA as a percentage of total mRNA. Thus, it appears that arachidonic acid possibly plays a role as a physiological regulator of prolactin secretion in human decidual tissues. The action of arachidonic acid is not mediated by cyclooxygenase or lipoxygenase products, suggesting that arachidonic acid itself, or its metabolites other than prostaglandin and leukotriene, may be involved in the regulation of prolactin secretion.

Arachidonic Acid↗
PubMed1990

[Effects of epidermal growth factor (EGF) on prostaglandin E2 synthesis by cultured human endometrial cells].

Prostaglandins are considered to participate in the nidation of the embryo. However, so far little is known about the regulation of prostaglandin synthesis in endometrial tissue. In this study, we examined the effect of epidermal growth factor (EGF) on the release of PGE2 with primary cell culture of human endometrium. EGF stimulated PGE2 release dose-dependently in the range between 0.1 ng/ml and 100 ng/ml. PGE2 release was augmented significantly as early as 30 minutes after the addition of EGF, reaching a plateau at 3 hours. The stimulatory effect of EGF was eliminated by the concomitant addition of lipocortin, an inhibitor of phospholipase A2. However, the effect of EGF was not influenced by cycloheximide. Estradiol alone had a weak effect on PGE2 release. However, the stimulatory effect of EGF was more pronounced in cells pretreated with estradiol. In conclusion, this report offers evidence that EGF stimulates the release of PGE2 from human endometrial cells, thus implying the involvement of EGF in implantation.

Adult↗
PubMed1990

The enhancement of liver injury by lipopolysaccharide in an experimental drug-induced allergic hepatitis model.

When guinea pigs sensitized with trinitrophenylated (TNPed) liver protein 1 (LP1) were intravenously injected with TNPed isolated hepatocytes, remarkable hepatic cell injury was induced 24 hours later. In this experimental model, drug-induced allergic liver injury was induced by using trinitrobenzen sulfonic acid (TNBS) as the hapten and LP1 as the carrier. When these sensitized guinea pigs were intravenously injected with 10 micrograms of lipopolysaccharide (LPS) along with TNPed isolated hepatocytes, serum AST and ALT levels were remarkably higher than those of the guinea pigs not injected with LPS. Hepatic cell necrosis was also more extensive, and some bleeding was observed. Although none of the guinea pigs died even after 24 hours, when 50 micrograms of LPS was injected, many of the guinea pigs started to die and the survival rate was 5% at 24 hours. These results suggested that LPS enhanced liver injury in this experimental drug-induced allergic liver injury model.

Animals↗
PubMed1990

[Influence of peritoneal fluid with endometriosis on the development of mouse embryos].

To clarify the mechanism of infertility associated with endometriosis (EM), the effect of peritoneal fluid (PF) on early embryogenesis was examined. The addition of PF (5%) had no effect on the development of mouse 2-cell embryos. Since the PF is supposed to enter the oviductal cavity, PF may influence reproductive processes by modulating the intraoviductal microenvironment. As expected, PF with EM inhibited the development of 2-cell embryos co-cultured with oviducts whereas PF without EM had no effect. An increase in interleukin 1 (IL-1) has been identified in PF with EM. As with PF with EM, IL-1 inhibited the development of 2-cell embryos inasmuch as the oviducts were co-cultured. Indomethacin, an inhibitor of prostaglandin (PG) synthesis, effectively abolished the inhibitory action of both PF with EM and IL-1 on embryonic development. Moreover, PGE2 directly inhibited embryonic development. PGE2 was shown to inhibit the synthesis of protein by early embryos. These results demonstrate that PF with EM inhibits the development of early mouse embryos by acting on the oviducts. From these results it seems that an increase in IL-1 may be a causative factor in the embryo-toxic properties of PF with EM. We further suggest that PGE2 secreted from the oviducts by stimulation with PF with EM, may be an ultimate contributing factor in embryo-toxicity by inhibiting protein synthesis by early embryos.

Animals↗
PubMed1990

[Combination of serial transcranial Doppler examinations and cerebral blood flow studies in the management of cerebral vasospasm after subarachnoid hemorrhage].

In 13 patients who had ruptured intracranial aneurysms, serial transcranial Doppler (TCD) and cerebral blood flow (CBF) examinations were performed in order to evaluate the degree of cerebral vasospasm. All patients showed some extent of vasospasm on angiography, which was performed between Day 7 and 10. The flow velocities of either the middle cerebral arteries or the anterior cerebral arteries, measured by TCD, began to increase on post hemorrhage Day 5, and maximum flow velocities were recorded between Day 9 and 13, with normalization occurring within the following 2 weeks. In 5 cases of symptomatic vasospasm, a rapid increase of flow velocities preceded clinical manifestation of the vasospasm. Maximum flow velocities of the 5 cases were at a higher level in the range of 119-184cm/sec (mean 149cm/sec) that the cases where there were no symptoms. Consequently, serial TCD examinations were very useful for the early detection of vasospasm after subarachnoid hemorrhage. And it was confirmed that the change of flow velocities was more important than the value itself, and that the rapid increase of flow velocities indicated severe ischemia. However, for judging when vessel narrowing was resolving, the usefulness of the TCD examinations were doubtful. This is because flow velocities measured by TCD are thought to be fairly much influenced by multiple factors such as the change of blood pressure, blood volume, which were caused by the active treatment for the vasospasm. Serial measurements of CBF were also made 2-7 times (mean 3.1 times) during the first two weeks following subarachnoid hemorrhage using the 133Xe intravenous injection method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Regional effects of craniotomy on cerebral circulation and metabolism: PET study on the un-ruptured aneurysmal surgery].

Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used.

Adult↗
PubMed1990

[The influence of liver and renal functions on the changes in serum methotrexate (MTX) level in high-dose MTX therapy].

Sixty times of high dose methotrexate (MTX) with citrovorum factor rescue (HDMTX-CF) therapy were applied for 15 patients with osteosarcoma. The serum level of MTX was measured at every 24 hr. by FPIA (Fluorescence Polarization Immuno Assay) method and blood analysis was performed at the same time. Fourtysix parameters were measured in each HDMTX-CF therapy and examined by multiple parameter statistical analyses by a personal computer. In the results, the number of performed chemotherapy, rescue time, serum GOT and creatinine level at 24 hr. were the most relative factors for the change of serum MTX level.

Adolescent↗
PubMed1990

[Intraventricular hematomas associated with hypertensive intracerebral hemorrhages: with special reference to third ventricular hematoma].

Intraventricular hematoma (IVH) is often associated with many kinds of intracranial hemorrhage; for example, hypertensive intracerebral hemorrhage, subarachnoid hemorrhage, and so on. In this paper we discuss the clinical significance of IVH in the third ventricle, as well as the effects of surgical treatment. Forty-five patients were treated in our hospital because of massive IVH associated with small or mode-rate-size (hematoma volume less than or equal to 15 ml) thalamic or caudate-head hemorrhage between April, 1983 and April, 1988. All cases had an intraventricular cast in at least one ventricle. The patients were divided into two subgroups (depending on the site of the dominant IVH): the third-fourth ventricle dominant type-IVH group, and the lateral ventricle dominant type-IVH group. The former was further divided into two subgroups based on the thickness of the IVH in the third ventricle (its thickness being greater than or equal to 1 cm and less than 1 cm), and the area of IVH in the fourth ventricle (its area being greater than or equal to 1 cm2 and less than 1 cm2) as determined by CT scan monitoring. All cases were also divided according to continuous ventricular drainage (CVD), position of the catheter tip (in either the third ventricle or the lateral ventricle), and the intraventricular administration of urokinase (UK). For each group we checked the consciousness grade using the Glasgow Coma Scale (GCS) on day 0 and on day 7, as well as the interval between day 0 and the day on which the IVH in the third ventricle disappeared on the CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1990

[Adult moyamoya disease with a transcranial internal carotid-external carotid (EC-IC) anastomosis through burr holes].

A case of adult Moyamoya disease, with formation of a transcranial external carotid-internal carotid (EC-IC) anastomosis through burr holes which had been made previously. A 43-year-old male suffered sudden headache and vomiting. Neurological examination revealed mild consciousness disturbance and dysarthria. The computed tomography (CT) scans showed intraventricular hemorrhage, which was drained through burr holes bifrontally. The diagnosis of Moyamoya disease was subsequently made by cerebral angiography. A month later he was discharged with mild gait disturbance and mental retardation. Seven years later he suddenly complained of gait disturbance, dysarthria and sensory disturbance involving the right upper extremity. A CT scan revealed a small hemorrhage in the left putamen. Carotid angiograms disclosed transcranial EC-IC anastomosis through the burr holes which had been made previously. It is suggested that revascularization can be expected after opening burr holes and incising the dura matter for Moyamoya disease in adults as well as, possibly, in children.

Anastomosis, Surgical↗
PubMed1989

Phospholipid metabolism in rat submandibular gland. Positional distribution of fatty acids in phosphatidylcholine and microsomal lysophospholipid acyltransferase systems concerning proliferation.

Rat submandibular gland phosphatidylcholine mainly consisted of the 1-saturated acyl-2-unsaturated acyl type. The high occupancy of unsaturated fatty acid at the C-2 position is in part explained by the preference of microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphocholine (1-acyl-GPC) acyltransferase for unsaturated fatty acyl-CoAs. This enzyme activity was partially inhibited by divalent cations. Ca2+ may be important for regulation of a deacylation-reacylation cycle, suggested because Ca2+ is also known to activate the deacylation enzyme, phospholipase A2. Although the presence of 1-acyl-GPC acyltransferase activity is also observed in plasma membrane of the submandibular gland, the microsomal enzyme showed properties different from the enzyme in plasma membrane in terms of its susceptibility to neural salts and detergents. Cell proliferation caused by chronic administration of isoproterenol resulted in an increase of linoleic acid at the C-2 position of phosphatidylcholine. However, this alteration did not correlate with the changes of activity and substrate specificity of 1-acyl-GPC acyltransferase and the other C-2 acylation enzyme, 1-acyl-sn-glycero-3-phosphate acyltransferase, which suggests that the alteration of fatty acid by isoproterenol treatment is due to a change of supply of substrates or specific acyl breakdown of phosphatidylcholine.

1-Acylglycerophosphocholine O-Acyltransferase↗