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Biomedical subjects

T Eguchi

Publications and source records attributed to T Eguchi.

At least 181 records · Page 10Linked to original sources
PubMed1986

Covalent linking of poly(ethyleneglycol)-bound NAD with Thermus thermophilus malate dehydrogenase. NAD(H)-regeneration unit for a coupled second-enzyme reaction.

Poly(ethyleneglycol)-bound NAD (PEG-NAD) was covalently linked to Thermus thermophilus malate dehydrogenase with a bifunctional reagent, 3,3'-(1,6-dioxo-1,6-hexanediyl)bis-2-thiazolidinethione. The covalently linked malate-dehydrogenase--PEG--NAD complex (MDH-PEG-NAD) was purified by DEAE-Sephadex column chromatography to remove unbound PEG-NAD, and fractionated by blue-Sepharose column chromatography into four preparations: MDH-PEG-NAD I, MDH-PEG-NAD II, MDH-PEG-NAD III and MDH-PEG-NAD IV. The average numbers of NAD moieties covalently bound per subunit of MDH-PEG-NAD I, MDH-PEG-NAD II, MDH-PEG-NAD III and MDH-PEG-NAD IV were 1.2, 1.2, 0.8 and 0.5, respectively, and the values were confirmed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. 60-80% bound NAD moiety of these preparations of MDH-PEG-NAD was reduced by the enzyme moiety in the presence of L-malate, and the specific activity of the enzyme moiety of the preparations was more than 80% that of the native enzyme. MDH-PEG-NAD I has the following properties. The Km value for exogenous NAD is three times that of the native enzyme. The coenzyme activity of its NAD moiety is 20-40% that of native NAD for alcohol and lactate dehydrogenases. The complex catalyzes the oxidation of L-malate in the presence of the redox system of 5-ethylphenazinium ethyl sulfate and a tetrazolium salt with a rate constant of 0.11 s-1. The coenzyme moiety of the complex can also be recycled by coupled reactions of the active site of the same complex and alcohol dehydrogenase. These results indicate that MDH-PEG-NAD works as an NAD(H)-regeneration unit for coupled reactions.

Coenzymes↗
PubMed1985

Evaluation of a new assay kit for intrinsic factor blocking antibody (type I) as an aid in the diagnosis of pernicious anemia.

Sera from 39 patients with pernicious anemia and 251 patients with various other diseases and 42 healthy normal subjects were tested for intrinsic factor blocking antibody by a Corning commercial kit. Twenty-five (64%) out of 39 pernicious anemia patients showed a positive reaction to the intrinsic factor blocking antibody. The positive incidence of intrinsic factor blocking antibody by this method agreed well with the results obtained in this laboratory over the past 10 years using the charcoal method. No sera from normal subjects tested were positive for the intrinsic factor blocking antibody. All 226 sera with vitamin B12 levels less than 3,500 pg/ml which came from patients without pernicious anemia, were negative for the intrinsic factor blocking antibody. In 15 sera with B12 levels greater than 3,500 pg/ml from patients who received recent B12 medications, 11 sera showed false positive results. On the other hand, no false positive results were obtained by this method in 10 sera with endogenous serum B12 levels greater than 3,500 pg/ml collected from patients with chronic myelogenous leukemia. It is reasonable to presume that this assay is clinically useful for detection of intrinsic factor blocking antibody in the diagnosis of pernicious anemia, if false positive results due to B12 medication are excluded.

Adolescent↗
PubMed1984

Humoral responses to intracerebroventricularly administered angiotensin II in dogs.

The mechanism(s) by which intracerebroventricularly administered angiotensin II (ANG II) regulates aldosterone production was investigated in dogs with chronically implanted cannula into a lateral cerebroventricle. In salt-replete and salt-depleted dogs, artificial cerebrospinal fluid (CSF) with or without ANG II (1, 10, 100 ng X kg-1 X min-1) was infused intracerebroventricularly for 2 h under pentobarbital anesthesia. Artificial CSF produced no significant humoral changes. Intracerebroventricular ANG II decreased plasma renin activity and increased both ACTH and plasma cortisol in both groups but decreased plasma aldosterone (PA) only in salt-depleted dogs. Dexamethasone pretreatment during intracerebroventricular ANG II decreased PA further in salt-replete but not in salt-depleted dogs. Moreover, the fall in PA during intracerebroventricular ANG II in salt-depleted dogs was prevented when intravenous infusion of ANG II (10 ng X kg-1 X min-1) was given simultaneously to maintain circulating ANG II levels. We conclude that PA response to intracerebroventricular ANG II is mediated primarily through the renin-angiotensin system in the salt-depleted state; however, in the salt-replete state, ACTH assumes a more important role.

Adrenocorticotropic Hormone↗
PubMed1984

[Some considerations on surgical approaches to the anterior communicating artery aneurysms--radiological study of 122 cases].

We studied the operative approaches to anterior communicating artery aneurysms by means of reviewing preoperative angiogram and operation records. During the past 5 years, 117 patients with anterior communicating artery aneurysms were operated on in our hospital. Among these, we examined 112 cases of which preoperative angiogram and operation records were satisfactory for this study. We checked the next points on the preoperative angiograms. Neck of aneurysm-planum sphenoidal distance. Direction of the anterior communicating artery. It means which A2 is anterior to the other A2 in the lateral view of angiogram. Size of aneurysm. We checked the next points on the operation records. Operative approach and the side of craniotomy. When the pterional approach was taken, the rectal gyrus was aspirated or not. This analysis derived these two conclusions as below. 1. In the literature, as the operative approach to anterior communicating artery aneurysm, the pterional approach has a lot of advantages. For example, the pterional approach was accomplished without extensive frontal lobe retraction, without mobilization of the temporal lobe, without sacrificing the olfactory tract, and so on. Moreover, in early stage after onset of SAH, it is possible to remove the subarachnoid blood extensively without obvious brain damage by the pterional approach. In this study, we paid attention to the correlation between the neck-planum sphenoidal distance and the fact of aspiration of the rectal gyrus in the pterional approach. The result is that the higher aneurysmal neck was, the more frequently the rectal gyrus was aspirated. So, if the neck-planum sphenoidal distance is under 12 mm, which includes the majority of the cases (94% of cases), we think the pterional approach is the best approach for anterior communicating artery aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Extracranial-intracranial bypass to the proximal posterior cerebral artery and to the proximal middle cerebral artery for multiple occlusive cerebrovascular disease.

A 48-year-old man with a multiple occlusive cerebrovascular disease involving both the carotid and the vertebrobasilar systems is reported. Faced with noneffective conservative treatment, a surgical approach was carried out. As the patient had poorly developed posterior communicating arteries, two extracranial-intracranial bypasses were performed for both the carotid and the vertebrobasilar circulations; extracranial-intracranial bypasses with interposed saphenous vein grafts between the left external carotid artery and the proximal segment of the left middle cerebral artery, and between the right external carotid artery and the proximal segment of the right posterior cerebral artery. Advantages, precautions, and techniques of this kind of bypass procedure are discussed.

Brain Ischemia↗
PubMed1983

Relationship between contrast enhancement on computed tomography and cerebral vasospasm in patients with subarachnoid hemorrhage.

To elucidate the relationship between abnormal enhancement of the cisterns on computed tomography and cerebral vasospasm, we performed a systematic and prospective study in 60 patients with ruptured cerebral aneurysms. There is a significant relationship between the findings of contrast-enhanced computed tomography (CECT) within Day 3 of rupture and cerebral vasospasm. Among 37 patients undergoing CECT between Day 0 and Day 3, 17 (46%) showed prominent increases in density in the region around the circle of Willis and its branches. In 13 of 17 cases (76%), severe vasospasm with motor paralysis occurred. In the remaining 4 cases (24%) with only slight or no cerebral vasospasm, the hematoma in the subarachnoid space was removed surgically by Day 3. In 19 of 20 cases without remarkable CECT, no severe cerebral vasospasm with motor paralysis occurred. There is no significant relationship between the CECT findings after Day 3 and cerebral vasospasm. The results indicate that the prominent increase in density in the region of the circle of Willis and its branches often observed on CECT within Day 3 of subarachnoid hemorrhage is useful for prediction of the occurrence of cerebral vasospasm and also provide information on the pathogenesis of cerebral vasospasm.

Aged↗
PubMed1983

[The migration of cefotiam to cerebrospinal fluid].

The concentration of cefotiam (CTM), a newly synthesized cephem derivative antibiotic in serum and cerebrospinal fluid after single intravenous treatment was determined and its utility in the field of cerebral neurosurgery was studied. 1. One gram or 2 g of CTM was intravenously administered for 1 time to 10 patients admitted to our department. Dose dependency was observed in the progress of the mean serum concentration. There was no difference in the specific rate of constant, and the ratio of AUC between the group treated with 1 g and the one with 2 g was 1:1.9. The biological half-lives of the elimination phase for both dose levels were about 1.1 hours. 2. Disparity was recognized in the cerebrospinal fluid concentration in spite of the dose dependency. Although a case with comparatively high value of 1.37 micrograms/ml at 60 minutes after administration were seen in the 1 g treatment group, generally the migration concentration was low. Good cerebrospinal fluid concentration was attained in all of the cases in the 2 g treatment group, and the peak values ranged from 0.59 to 10.16 micrograms/ml. 3. The concentration ratio of cerebrospinal fluid to serum in the 2 g treatment group elevated till 360 minutes after administration, and the maximum values ranged from 15.8 to 89.8%. 4. The migration to the cerebrospinal fluid was faster in cases with slight inflammation than those without inflammation in the 2 g treatment group. 5. It was assumed that the prophylactic effect of CTM 2 g administration against staphylococci, streptococci and Klebsiella pneumoniae which are the major causative organisms can be expected in postoperative infection in the field of cerebral neurosurgery.

Adult↗