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Biomedical subjects

T Kurimoto

Publications and source records attributed to T Kurimoto.

At least 37 records · Page 2Linked to original sources

Quantification of infarct size by thallium-201 single-photon emission computed tomography using the unfolded map method. Comparison with QRS score and angiographic infarct size at 4 weeks after infarction.

A new technique of data processing, the unfolded map method, was used with thallium-201 single-photon emission computed tomography to quantify infarct size in 35 patients with single-vessel disease at 4 weeks after their first myocardial infarction (24 anterior and 11 inferior infarcts), and the results were compared with those obtained by electrocardiography and contrast left ventriculography. The myocardial borders and the infarcted region were defined using the threshold technique and a cutoff value of 55%. Count profile data for each short-axis slice were unfolded zonally into single planes with the same ratio, and their areas were calculated from the slice thickness and radius. Thus, the size of the unfolded map represented the actual left ventricular myocardial area Infarct size was quantitated from the ratio of pixels in the infarcted region to those in the whole map, and the ratio itself was used as the percent infarct size. Although a defect 1 cm in diameter (0.8 cm2) could not be detected in a phantom study, defects > or = 2 cm in diameter (> or = 3.1 cm2) could be measured satisfactorily. The infarct size and percent infarct size determined by the unfolded map method correlated well with the QRS score (r = 0.841 and r = 0.838), the percentage of abnormally contracting segments on left ventriculography (r = 0.835 and r = 0.877), and the ejection fraction (r = -0.835 and r = 0.856). These data indicate that the unfolded map method provides adequate quantification of infarct size, even in the chronic phase, without complicated data processing.

Adult↗

The anticonvulsant effect of citalopram on El mice, and the levels of tryptophan and tyrosine and their metabolites in the brain.

Serotonin(5-HT) plays an important role in the seizures of El mice since the seizure threshold of El mice correlates with the 5-HT concentration in the central nervous system. In this study, the anticonvulsant effect of a 5-HT reuptake blocker, citalopram, was evaluated behaviorally and biochemically. El mouse convulsions were inhibited by oral administration of citalopram for 2 weeks. Citalopram increased tryptophan and tyrosine amounts, and decreased the 5-HT, 5-hydroxyindoleacetic acid, kynurenine, and dopamine amounts in the brain. These findings show that citalopram depresses monoaminergic metabolism. Given the known convulsant effect of kynurenine, it is suggested that its decrease by citalopram may involve attenuation of El mice seizures.

Animals↗

Chronic administration of citalopram inhibited El mouse convulsions and decreased monoamine oxidase-A activity.

Serotonin (5-HT) is thought to play an important role in the seizures of El mice because the seizure threshold of El mice correlates with the 5-HT concentration in the central nervous system. In this study, the anticonvulsant effect of a 5-HT reuptake blocker, citalopram, was evaluated behaviorally and biochemically. El mouse convulsions were inhibited by chronic administration of citalopram (80 mg/kg/day, p.o. for 2 weeks), but were not inhibited by acute administration of citalopram (80 mg/kg, i.p., 2 h after single injection). Both chronic and acute administration of citalopram decreased the concentration of 5-hydroxyindolacetic acid in the brain, whereas the concentration of 5-HT was not changed by treatment with citalopram. Tryptophan hydroxylase activity was not different between the citalopram and control groups, although the monoamine oxydase-A activity was lowered by chronic administration of citalopram. These findings suggest that both acute and chronic administration of citalopram depresses the 5-HT turnover rate, however chronic administration is necessary to inhibit El mouse convulsions.

Administration, Oral↗

[Effects of NC-1100, a calcium channel blocker, on experimental cerebral ischemia/anoxia in rodents].

The anti-ischemic and anoxic effects of NC-1100, a piperazine type calcium channel blocker, were investigated in various cerebral ischemia and anoxia models in mice, gerbils and guinea pigs. Minimal effective doses of NC-1100 were 8 mg/kg, i.p. and 30 mg/kg, p.o. for KCN-induced anoxia; 16 mg/kg, i.p. for decapitation-induced gasping; 30 mg/kg, i.p. for cerebral ischemia induced by occlusion of bilateral carotid arteries in gerbils; and 10 microM for the in vitro ischemic model in hippocampal slices. Moreover, NC-1100 attenuated the disturbance of cerebral energy metabolism induced by decapitation in mice. These results suggest that NC-1100 has a cerebral protective effect, and that attributable to its ability to improve the cerebral energy metabolism disturbance.

Animals↗

Respiratory activities in relation to palatal muscle contraction.

This study investigated the activities of the tensor and levator veli palatini muscles related to respiration. During quiet breathing, no activity was observed in either muscle. With either hypercapnic or hypoxemic condition, the tensor veli palatini muscle exhibited phasic activity during inspiration. The levator veli palatini muscle showed phasic activity during expiration with hypoxemia (PaO2 less than 40 mm Hg). NaCN perfused bilaterally through the carotid sinus induced these respiratory activities. The tensor veli palatini muscle was more sensitive than the levator veli palatini muscle to NaCN.

Animals↗

[A study on work and daily life factors affecting the health of taxi drivers].

In order to elucidate factors affecting taxi drivers health, a questionnaire survey was performed on 5523 taxi drivers and health examinations were conducted on 311 taxi drivers from among them. Analysis by a method of multivariate analysis called Quantification II was performed with dependent variables being blood pressure, the number of subjective symptoms and fatigue on rising, and independent variables being work and daily life conditions. The major results of this survey were as follows: 1) A tendency for hypertension risk to increase with degree of obesity, and both employment as a taxi driver for 1-4 years and over twenty years of taxi driving were positively associated with increase in risk for hypertension. 2) Common factors to all types of work shifts which were related to an increase in the number of subjective symptoms were irregularity of meals, insufficient rest on off days, large number of years engagement at taxi driving, frequent frightening experiences while driving and comparatively short driving distance in one shift. 3) Common factors to all types of work shifts that were connected with fatigue at the time of rising were insufficient rest on off days and long years engagement in taxi driving.

Activities of Daily Living↗

Phase I study on human monoclonal antibody against cytomegalovirus: pharmacokinetics and immunogenicity.

MAb C23, a human immunoglobulin G1 (IgG1) monoclonal antibody (MAb) against cytomegalovirus, was administered to 20 healthy volunteers. Sixteen of them received a single infusion of a dose ranging from 5 to 80 mg. The plasma clearance curves fit a two-compartment model, with half-lives of 31.0 +/- 23.6 h in the diffusion phase and 24.2 +/- 5.8 days in the equilibration phase. The plasma after administration had the virus neutralization activities that were equivalent to the plasma MAb C23 levels. The remaining four subjects, who received three infusions of 60, 20, and 20 mg at 1-week intervals, showed pharmacokinetics that were very consistent with those of the single infusion. No antibody response against MAb C23 was observed in any of the subjects at any time, when monitored for approximately 60 days after the single infusion or the third infusion of the three repeated doses. None of the 20 subjects showed any treatment-related clinical signs or changes. These results suggest that a human IgG MAb has the same pharmacokinetic characteristics as those of natural human serum IgG, and that it is not immunogenetic and is safe in humans.

Antibodies, Anti-Idiotypic↗

[Basal studies on the model of circular excisional wounds made on the dorsal skin of rats treated with hydrocortisone].

This study was performed to establish a circular excisional wound model treated with hydrocortisone (HC-P) and to estimate the following parameters in this model: wound area, hydroxyproline (Hyp) content, histological characteristics and microscopical measurements of histological sections. HC-P inhibited the reduction of wound area, the increase in Hyp content and proliferation of granulation tissue in a dose-dependent manner. The application of ZnO ointment significantly accelerated the reduction of wound area and the increased Hyp content in rats treated with HC-P. From these results, we concluded that this experimental model is useful for the objective evaluation of the efficacy of drugs that promote wound healing.

Animals↗

Optimization of cell culture conditions for production of biologically active proteins.

We investigated the basic technology of cell culture conditions for production of useful substances such as cytokines, and related proteins produced by Namalwa cells. Namalwa cells (Klein, 1972), human B lymphoblastoid cells, were used for large scale production of alpha-interferon (Klein, 1979). Namalwa KJM-1, a subline of Namalwa cells, adapted to serum- and albumin-free medium, can grow at a high density above 1 x 10(7) cells/ml in suspension mode by the use of a perfusion culture system, Biofermenter, containing a cone-type cell-sedimentation column as cell separator (Sato, 1983). Several kinds of cytokine cDNA can be introduced and expressed in Namalwa KJM-1 cells (Miyaji, 1990a,b,c). Some of these were produced in large quantities by use of a gene amplification method with dhfr (Miyaji, 1990c), even though the Namalwa KJM-1 cells contained endogenous dhfr genes. For stable production of the target protein, Namalwa KJM-1 cells are very useful host cells, because they have no effective endogenous protease activity in the conditioned medium. Using Biofermenter with micro-silicone fibers and a dialysis system, the specific productivity of the target proteins was not depressed at a high cell density.

Amino Acid Sequence↗

Effects of the new anti-ulcer drug nizatidine on prostaglandins in the rat gastric mucosa.

The effects of nizatidine (N-[2-[[[2-[(dimethylamino)methyl]- 4-thiazolyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine , CAS 76963-41-2), a new histamine H2-receptor antagonist, on the content of prostaglandins (PGs) in the rat gastric mucosa at doses that inhibit basal gastric acid secretion were compared with those of two other histamine H2-receptor antagonists, cimetidine and ranitidine. Nizatidine did not inhibit basal gastric acid secretion at a dose of 0.4 mg/kg but showed dose-dependent inhibition at doses of 10, 30, and 100 mg/kg. This drug had no effects on the content of PG in the gastric mucosa when subcutaneously administered at doses of 0.4, 10, 30 and 100 mg/kg once daily for 5 days. Cimetidine and ranitidine administered at doses that markedly inhibit basal gastric acid secretion (250 and 100 mg/kg/d, respectively) had no effects on the content of PG in the gastric mucosa. On the other hand, nizatidine, cimetidine, or ranitidine at concentrations of 1-100 mumols/l did not inhibit in vitro PGE2 synthesis using sheep seminal vesicle microsomes. These results suggest that nizatidine did not affect in vitro PGE2 synthesis and even doses that markedly inhibit gastric acid secretion had no effects on the content of PGs in the gastric mucosa.

6-Ketoprostaglandin F1 alpha↗

Effects of successive doses of nizatidine, cimetidine and ranitidine on serum gastrin level and gastric acid secretion.

Nizatidine (N-[2-[[[2-[(dimethylamino)methyl]- 4-thiazolyl]methyl]thio]ethyl]-N'-methyl-2-nitro-1,1-ethenediamine , CAS 76963-41-2) is a new histamine H2-receptor antagonist which shows suppression of gastric acid secretion and antiulcer activity. In the present experiment, the effects of single s.c. administration of nizatidine, cimetidine and ranitidine on serum gastrin levels were studied in fasted rats. Nizatidine at 100 mg/kg increased serum gastrin level 3 h after administration, which however, returned to basal level 6 h after administration. Cimetidine and ranitidine at respective doses of 250 and 100 mg/kg markedly increased serum gastrin levels 3 and 6 h after administration. In a previous study, the suppressive effect of nizatidine on basal gastric acid secretion was 82.8% at a dose of 100 mg/kg s.c. in rat pylrus-ligated model. On the basis of these findings, changes in basal gastric acid secretion and serum gastrin level after withdrawal of nizatidine, cimetidine and ranitidine administered for 14 consecutive days were studied. One day after withdrawal, nizatidine at 100 mg/kg showed a tendency to increase the basal gastric acid secretion. However, 3 and 7 days after administration, almost no changes were obtained. Cimetidine at 250 mg/kg showed a tendency to increase the basal gastric acid secretion 7 days after withdrawal of the drug. Ranitidine at 100 mg/kg induced no changes in basal gastric acid secretion after withdrawal. No obvious influences of all drugs on serum gastrin level after withdrawals were obtained. These results indicate that consecutive administration of nizatidine may cause only a transient increase of gastric acid secretion but no hypergastrinaemia after its withdrawal.

Animals↗

[Chemical composition and biological activities of lipopolysaccharides extracted from Treponema denticola and Treponema vincentii].

Lipopolysaccharides (LPSs) were isolated from Treponema denticola (T. denticola) and Treponema vincentii (T. vincentii) by the phenol/water (PW) and the phenol/chloroform/petroleum-ether (PCP) procedures. 1) T. denticola PW-LPS (LPS isolated by the PW procedure), PCP-sup-LPS (LPS isolated by the PCP procedure in the supernates of ultracentrifugation), PCP-ppt-LPS (precipitated LPS isolated by the PCP procedure, obtained after ultracentrifugation), and T. vincentii PCP-ppt-LPS were composed of carbohydrate, hexosamine, protein, fatty acid, and phosphorus. T. vincentii PW-LPS was contained major amount of carbohydrates and small amount of fatty acids. 2-keto-3-deoxyoctonic acid (KDD) was not detected in these LPSs. 2) The major fatty acids of T. denticola PW-LPS and PCP-sup-LPS were palmitic, stearic, oleic, and linoleic acids. The major fatty acids of T. vincentii PCP-ppt-LPS were palmitic, stearic, myristic, oleic, and linoleic acids. Hydroxy fatty acids were not detected. 3) Glucose, galactose, and mannose were comprised in T. denticola PW-LPS. Glucose, galactose, and arabinose were comprised in T. denticola PCP-sup-LPS. Glucose and galactose were comprised in T. vincentii PCP-ppt-LPS. 4) The Limulus amoebocyte lysate (LAL) clotting activity of T. denticola PW-LPS was 1/10, as compared with that of Escherichia coli (E. coli) UKT-B LPS standard. The LAL clotting activities of T. denticola PCP-sup-LPS, T. vincentii PW-LPS, and T. vincentii PCP-ppt-LPS were 1/100, as compared with that of E. coli LPS standard. 5) Five hundred micrograms/kg of T. denticola PCP-sup-LPS was pyrogenic in rabbits. Two thousand micrograms/kg of T. vincentii PCP-ppt-LPS was pyrogenic in rabbits. 6) T. denticola PCP-sup-LPS and T. vincentii PCP-ppt-LPS were capable of increasing or decreasing the release of lysosomal enzymes from human polymorphonuclear leukocytes.

Endotoxins↗

[The role and clinical value of thallium-201 myocardial scintigraphy in ischemic heart disease].

To define the role and clinical value of thallium-201 myocardial scintigraphy in ischemic heart disease, 967 consecutive patients referred to our laboratory since 1985 were studied. The purpose of scintigraphy has changed from diagnosing myocardial ischemia to assessing myocardial viability with the progress of coronary angioplasty. At present, thallium-201 myocardial scintigraphy has become an indispensable noninvasive method for the management of patients with ischemic heart disease.

Adolescent↗

Relationship between the coronary diameter and occurrence of vasospastic angina in patients with normal coronary arteries.

Coronary artery diameters were measured after various interventions in 30 patients without angina pectoris (group 1) and in 15 with angina pectoris (group 2: rest, or rest and effort angina) who had normal coronary arteries. The coronary artery diameters were significantly smaller in many coronary segments in group 2 than in group 1 during a control state, after exercise and ergonovine, but became nearly identical after isosorbide dinitrate in both groups. Patients in group 1 had diffuse narrowing but no focal vasoconstriction after ergonovine and all the segments had a diameter of more than 50% of that after isosorbide dinitrate. The change of coronary artery diameter in group 2 patients who had no vasospasm by ergonovine was the same as that in group 1. Patients in whom vasospastic angina was induced had local vasoconstriction or severe diffuse narrowing (less than 45%). These results indicate that angina pectoris patients with normal coronary arteries had an acceleration of coronary arterial basal tone, but vasospastic angina pectoris was not induced just by the general response of the coronary artery to various interventions in addition to the accentuated basal tone. For vasospastic angina to occur, local abnormal response to various interventions must be present.

Adult↗

[Prognostic factors in acute subdural hematoma and the significance of serum FDP measurement].

Sixty-two cases of acute subdural hematoma were clinically analyzed with special reference to such prognostic factors as age, Glasgow Coma Scale (GCS) score on admission, pupillary signs, decerebration, and initial computed tomography (CT) findings. Intraparenchymal lesions demonstrated by CT were evaluated according to Yamaura's classification. In 19 cases, serum fibrin and fibrinogen degradation products (FDP) were measured at the time of admission. Emergency surgery was performed in 46 cases, and the remaining 16 patients were treated conservatively. The final outcome was judged according to the Glasgow Outcome Scale, and patients were divided into a "good outcome" group (good recovery or moderate disability) and a "poor outcome" group (severe disability, vegetative state, or death). In general, the outcomes proved to be unsatisfactory. Forty-four patients (71%) had a poor outcome, with 32/62 (52%) mortality, and only 18 (29%) had a good outcome. The clinical factors associated with a poor outcome were age over 64 years, a GCS score on admission of less than 7, decerebration, and absence of pupillary reaction to light. Initial CT scans showed brain damage in 46 patients (74%), 39 (85%) of whom had a poor outcome. This indicates that the outcome was significantly related to brain injury complicating the acute subdural hematoma. A high serum FDP level was similarly related to a poor outcome, which suggests that the serum FDP level reflects the degree of both primary and secondary brain injury. Thus, measurement of serum FDP may be valuable both in assessing clinical status and in evaluating the extent of brain injury in acute subdural hematoma.

Acute Disease↗