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Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 667 records · Page 37Linked to original sources
PubMed1995

[Hemodynamics of the transverse sinus using cine angiography].

Numerous anatomical observations of the transverse sinus (TS) have been reported and features of this sinus, as assessed by cerebral angiography, are referred to in many monographs. However, there are no studies on the hemodynamics in the TS. We recently investigated the TS, using cerebral angiography with cinematographic films. The subjects were 35 patients who underwent angiography of 3 or 4 vessels at our institute, using Seldinger's method. The contrast material was infused manually. Cinematography permitted observation of the size of the bilateral TS and the direction of blood flow. Depending on the features of the bilateral TS, the patients could be divided into three groups. Type I (cases where the right TS was dominant) accounted for the highest percentage (54.3%, 19/35). In 11 of these 19 cases, the left TS also showed antegrade blood flow. In 6 of the Type I group, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus). In the other two cases rated as Type I, the blood flow through the left TS was in the direction from the Torcular Herophili to the right TS. Fourteen cases (40.0%) were rated as Type II (in which both sinuses were similar in size). In 13 of these 14 cases, blood flow through the bilateral TS was almost symmetrical (Type II-A). In one of the 14 cases, the blood flow through the left TS was in two directions (towards the Torcular Herophili and towards the left sigmoid sinus).

Aneurysm, Ruptured↗
PubMed1995

[Lifestyles and renal damage--association of smoking, drinking and physical activity with subsequent proteinuria].

To examine the role of lifestyles in the subsequent development of renal damage, the association of smoking, drinking and physical activity with subsequent proteinuria was investigated utilizing a longitudinal study. The subjects were 7,701 males aged 20-84 years, who participated in health examinations at Aichi Prefectural Center of Health Care, Nagoya, Japan, both in 1989-1990 and 1992-1993, and who showed no proteinuria at the first examination. Lifestyles at the first examination were compared between 140 men with, and 7,561 men without, newly developed proteinuria at the second examination. Age-adjusted odds ratios (ORs) of lifestyle factors for proteinuria were computed, and further the ORs were adjusted for age, systolic blood pressure, fasting plasma glucose level and other covariates obtained using multiple logistic regression analysis. Major significant findings which emerged from the present study were as follows. (a) The greater the consumption of alcohol per day, the higher the risk of subsequent proteinuria (trend p = 0.003). Heavy drinkers who consumed more than 58 g of alcohol per day experienced an increased risk (OR relative to non-drinker: 2.52). (b) Those who exercised less than once a week, and those who avoided walking even a short distance were at an increased risk (OR: 1.46, 1.55, respectively). Heavy drinking and low physical activity were found to be significantly associated with an increased risk of subsequent proteinuria even after adjusting for the covariates. An increasing risk of subsequent proteinuria with number of cigarette smoked per day was observed by univariate and multivariate analysis but without statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical evaluation of FemoStop in arrest of hemorrhage of the femoral artery].

A new device, FemoStop, in which the compression bag is replaced with a translucent one made of polyethylene for easy inspection, was used in 74 patients (76 examinations) who underwent angiography, including the setting of indwelling catheters in 10 patients, to obtain an easy and reliable maneuver for arresting hemorrhage at the puncture site. No failure in arrest of hemorrhage was recognized, and complications such as hematoma and re-bleeding were nonexistent. The doctor's time required for the arrest of hemorrhage was less than 5 minutes. On the other hand, in a beginner using the conventional manual compression method in 74 patients (74 examinations), the rate of failing to arrest hemorrhage was 5/74 cases, small hematoma was seen in three cases, re-bleeding occurred in one, and the time required for arrest was about 20 minutes. In conclusion, FemoStop was clinically useful for beginners.

Adolescent↗
PubMed1995

[Effect of body weight reduction on blood pressure and biochemical data].

The purpose of this study was to investigate the relation between body weight reduction and some complications associated with obesity. The subjects were 248 middle-aged obese persons (male 37, female 209) who participated in a weight reduction program at the Aichi Prefectural Center of Health Care from 1983 to 1990. The subjects had no severe complication, and the obesity indexes of all of them were over 120%. The program was held monthly for five months and consisted of diet (1500 kcal/day) and exercise (10000 walk steps/day). After the program, mean obesity index decreased by about 9%, and mean body weight reduction was about 5kg. Blood pressure, total cholesterol, triglyceride and GPT were significantly decreased, and HDL cholesterol was slightly increased. For each item the percentage of persons with abnormal values reduced by about 5 to 20%. From the relationship between degree of decrease of obesity and changes of the values of each item, it was estimated that some complications of obesity require greater than 5 to 10% decrease in obesity index to be affected. The value of each examination item before the program and the degree of decrease of obesity index had an effect on changes of the values, but obesity index before the program and age had little effect.

Adult↗
PubMed1995

[A study of infarction in the region of the anterior inferior cerebellar artery].

Sixteen patients with infarction in the region supplied by the anterior inferior cerebellar artery (AICA) were studied to assess the mechanism and its clinical features. Risk factors involved hypertension, diabetes mellitus, a history of cerebrovascular disease and hyperlipidemia in seven patients (44%), while smoking was found in six (38%). The pathogenesis of these patients was thought to be thrombotic in all 16 patients, and lesions of the vertebrobasilar system were noted in 7 out of 13 patients (54%) who underwent cerebral angiography. Gasperini syndrome (AICA syndrome+abducens paralysis) occurred in two patients (13%), and five patients (31%) showed only cerebellar ataxia (3 had infarction confined to the middle cerebellar penduncle and 2 had infarction confined to the cerebellar hemisphere). As a result of analysis of clinical symptoms in nine patients with the incomplete AICA syndrome, loss of hearing in six patients (67%) and cerebellar ataxia in all nine patients were noted. We postulated that large-artery occlusive disease or branch atheromatous disease resulted in an infarction in the region of the AICA. It is necessary to consider infarction of the AICA region in patients who present a unilateral hearing loss and cerebellar ataxia.

Aged↗
PubMed1995

[A case of Guillain-Barré syndrome associated with anti-GM2 antibody due to cytomegalovirus infection--special reference to the effect of ganciclovir].

We report a case of Guillain-Barré syndrome (GBS) associated with anti-GM2 antibody caused by cytomegalovirus (CMV) infection. A 27-year-old man was admitted to our hospital because of muscle weakness in all his extremities. He had no background of immunological abnormalities. Within 5 days, generalized muscular weakness had progressed so rapidly that he suffered respiratory dysfunction and dysphagia. Throughout the entire clinical course, enzyme immunoassay (serum) and enzyme-linked immunosorbent assay (CSF) for CMV were carried out serially. Only antibodies against CMV were elevated during the clinical course in the serum and CSF. These findings supported the idea that he had developed GBS due to isolated CMV infection. We examined the reactivity of GBS sera with crude ganglioside fraction, and only anti-GM2 antibody was recognized on a high-performance thin-layer chromatogram plate in this case. Although the anti-GM2 antibody was decreased transiently by plasmapheresis, the clinical symptoms progressed. The symptoms advanced very rapidly during high-dose gammaglobulin therapy associated with reelevation of the anti-GM2 antibody. Following ganciclovir administration, however, the symptoms became diminished within 7 days and the anti-GM2 antibody fell dramatically. We speculate that the reason for the observed effectiveness of ganciclovir was direct suppression of activation of CMV, followed by the inhibition of the production of demyelinating antibodies including the anti-GM2 antibody.

Adult↗
PubMed1995

[Histological evaluation of lung cancer with T2-weighted magnetic resonance images].

We investigated the differences in signal intensity of lung cancer tissue and non-cancerous lung tissues on T2-weighted magnetic resonance (MR) images. MR images were obtained from patients with squamous cell carcinoma (n = 6), adenocarcinoma (n = 5), small cell carcinoma (n = 5), and large cell carcinoma (n = 1). To compare the MR signal intensity between tissues, we calculated the signal intensity ratios for tumor/skeletal muscle and lung/skeletal muscle. The MR signal intensity for each tissue was measured with a densitometer and T2-weighted MR images with a similar window and a center. The value of the signal intensity ratio for squamous cell carcinoma (3.26 +/- 0.76) was greater than those for adenocarcinoma (1.99 +/- 0.50, p < 0.05), small cell carcinoma (2.35 +/- 0.60), large cell carcinoma (2.46), and non-cancerous lung tissues (1.70 +/- 0.68, p < 0.02). The values of the MR signal intensity ratio for non-cancerous lung tissues were 2.00 for a collapsed lung, 0.93 for a firotic lung, and 2.18 for a fibrotic lung with obstructive pneumonia. The results suggest that the MR signal intensity ratio for pathologic tissues/normal skeletal muscle can be a useful indicator for qualitative and quantitative MR imaging diagnosis.

Adenocarcinoma↗
PubMed1995

[Overexpressed p53 protein and cell-proliferative activity disappear or remarkably decrease in neoplastic CGA-positive endocrine and Paneth cells in cancer or dysplasia of ulcerative colitis].

We examined over-expression of p53 protein and proliferative activity of neoplastic endocrine and Paneth cells in cancer or dysplasia of ulcerative colitis (UC). The labeling index of p53 or Ki-67 of endocrine cells was counted with double immunostaining of p53 or Ki-67 and chromogranin A (CGA). 540 CGA-positive cells and 65 Paneth cells were all negative for p53. 5.1% of CGA-positive cells and none of 56 Paneth cells were positive for Ki-67 reaction. These observation suggest that even in cancer or dysplasia of UC cell-differentiation to neoplastic endocrine and Paneth cells decrease proliferative activity, and that these types of cell-differentiation suppress over-expression of p53 protein.

Cell Division↗
PubMed1995

Circadian rhythm sleep disorders: a brief review with special reference to long-term follow-up.

This article reviews the hygiene of new sleep disorders such as delayed sleep phase syndrome (DSPS) and non-24-hour sleep-wake syndrome which are classified as the circadian rhythm sleep disorders in the International Classification of Sleep Disorders (ICSD) published in 1990. It was clear in this study that these sleep schedule disturbances developed by preference in adolescence and youth, and the prevalence of DSPS in this generation was presumed to be 0.25-0.4%. Patients with certain disorders, such as entrainment to external time cues, were treated with non-pharmacological interventions and/or pharmacological agents. These therapies were effective in some cases when each was administered alone, but their effectiveness in other cases was not evident until two or more of therapies were used in combination. The prognosis of these two syndromes was significantly positive, particularly in the adolescent cases, suggesting the benefits of early discovery and treatment.

Chronic Disease↗
PubMed1995

[A study of eight patients with non-paralytic pontine exotropia].

We reported 8 patients with non-paralytic pontine exotropia (NPPE): 7 men and 1 woman aged from 56 to 79 years (mean: 67.8 years). From 1991 to 1994, 402 patients with acute infratentrial cerebrovascular diseases other than subarachnoid hemorrhage were admitted to our hospital within 7 days after the ouset of their stroke. NPPE was observed in 2% of these patients. NPPE was noted on admission in 6 of them, while it developed during the hospital stay in 2 others with paralytic pontine exotropia and bilateral median longitudinal fasciculus (MLF) syndrome, respectively. Abnormal convergence and alternating exotropia were noted in 6 and 2 patients respectively. The duration of NPPE was 0.5 to 4 days (mean; 2 days), and the ocular movement disorder was transient in all patients. When MRI was performed to detect the causative lesion, a small infarct was found in the upper, middle, and lower pons in 1, 3, and 4 patients, respectively. NPPE is generally considered to develop when the MLF and the paramedian pontine reticular formation (PPRF) are completely and incompletely destroyed respectively. In the present study, however, the pathophysiological features of the NPPE patients with alternating exotropia could not be explained by this mechanism, and severe MLF damage was considered to be a contributory factor.

Aged↗
PubMed1994

Isolation of Dictyostelium discoideum cytokinesis mutants by restriction enzyme-mediated integration of the blasticidin S resistance marker.

We have developed an improved REMI (restriction enzyme-mediated integration) system for generating mutant Dictyostelium cells quickly and efficiently for systematic screening of cytokinesis mutants. By means of this system, three cytokinesis mutants that grow as giant and multinucleate cells were isolated from 2,000 Dictyostelium transformants. Southern blot analysis of these mutants revealed that a single copy of the tag DNA was integrated into each genome. The tag with flanking genomic DNA at both ends was rescued from one of the mutants and reintroduced into the parental Ax2 strain. Homologous recombination of the rescued gene and the Dictyostelium genome led to the phenotypical changes expected for cytokinesis mutants.

Animals↗
PubMed1994

Nodularin, a potent inhibitor of protein phosphatases 1 and 2A, is a new environmental carcinogen in male F344 rat liver.

Nodularin and microcystin-LR are cyanobacterial toxins and environmental hazards. Nodularin inhibits protein phosphatases 1 and 2A with the same potency as does microcystin-LR, which has recently been identified as a potent tumor promoter in rat liver. Our results suggested that nodularin is also a new tumor promoter in rat liver. A two-stage carcinogenesis experiment in rat liver initiated with diethylnitrosamine and without partial hepatectomy revealed that nodularin stimulated glutathione S-transferase placental form-positive foci in rat liver more effectively than did microcystin-LR, and that nodularin alone induced glutathione S-transferase placental form-positive foci as well as did diethylnitrosamine alone. Thus, nodularin itself is a new liver carcinogen, and microcystin-LR is a tumor promoter rather than a carcinogen. Nodularin induced hyperphosphorylation of cytokeratin peptides 8 and 18 in primary cultured rat hepatocytes 20% more effectively than did microcystin-LR, suggesting that nodularin penetrates more easily into the hepatocytes than does microcystin-LR. Nodularin up-regulated induction of c-jun, jun-B,jun-D,c-fos,fos-B, and fra-1 mRNA transcripts in rat liver after i.p. administration, and the accumulation of the mRNA transcripts was sustained for over 9 h after treatment. The environmental hazards of cyanobacterial toxins are discussed in relation to human primary liver cancer in Qidong county in the People's Republic of China. Our results support this hypothesis and indicate the need for prevention measures against cyanobacterial toxins.

Animals↗
PubMed1994

Interaction between apo A-I-containing lipoproteins and lecithin:cholesterol acyltransferase.

HDL2 and HDL3 subfractions of two species of apo A-I-containing lipoprotein, one containing only apo A-I (LpA-I) and the other containing both apo A-I and apo A-II (LpA-I/A-II), were tested for reactivity to lecithin:cholesterol acyltransferase (LCAT). These subfractions and their mixtures were incubated with lipoprotein-deficient plasma (LCAT source), and the rate of cholesterol esterification and kinetic parameters were determined. Apparent Vmax (appVmax) and apparent Km (appKm) for HDL2 subfractions of LpA-I and LpA-I/A-II were significantly lower than those of their HDL3 counterparts. Differences between subfractions were much more prominent in LpA-I than in LpA-I/A-II. appVmax of the HDL2 subfraction of LpA-I (LpA-IHDL2) was one-fifth, and appKm was one-third of those for the HDL3 subfraction (LpA-IHDL3). appVmax and appKm of LpA-IHDL2 were both lowest among the apo A-I-containing lipoprotein subfractions. When LpA-IHDL2 was added to other subfractions, the molar rate of cholesterol esterification was suppressed. Since LpA-IHDL2 consists of a particle 11.1 nm in diameter, our observations suggest that LpA-IHDL2 suppresses cholesterol esterification in apo A-I-containing lipoprotein, possibly by displacing LCAT from other subfractions with higher appKm and higher appVmax to 11.1 nm LpA-I particles with lower appKm and lower appVmax. All of these data suggest that the relative amount of 11.1 nm LpA-I particles in plasma regulates the reactivity of apo A-I-containing lipoprotein to LCAT and may play a key role on the production of cholesteryl esters in plasma.

Apolipoprotein A-I↗
PubMed1994

Differentiation-dependent expression of the Na+/glucose cotransporter (SGLT1) in LLC-PK1 cells: role of protein kinase C activation and ongoing transcription.

We examined changes in the mRNA level of SGLT1, a Na+/glucose cotransporter, by the differentiation status of LLC-PK1 renal epithelial cells. Proliferating (undifferentiated) cells revealed no detectable SGLT1 mRNA by Northern blot analysis. However, when cells became confluent and differentiated into polarized monolayers, there was an abrupt appearance of the SGLT1 mRNA. When confluent (differentiated) cells were dedifferentiated by reseeding at a subconfluent density, SGLT1 mRNA levels decreased quickly to nondetectable levels (t1/2 = 1.5 h), while the mRNA levels of gamma-glutamyltranspeptidase, another differentiation marker, decreased only slowly (t1/2 > 40 h). This decrease in SGLT1 mRNA was completely blocked by H-7, a protein kinase inhibitor. Since protein kinase C was highly activated in the undifferentiated cells and treatment of differentiated cells with a phorbol ester also induced quick and complete loss of SGLT1 mRNA (t1/2 = 1.5 h) but not of gamma-glutamyltranspeptidase mRNA, protein kinase C activation appears to be involved in the dedifferentiation-induced decrease in SGLT1 mRNA. Although the phorbol ester-induced decrease in the SGLT1 mRNA level was blocked completely by inhibition of transcription, inhibitors of translation blocked the decrease in mRNA levels only partially.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1994

Effects of DNA repair deficiency on the mutational specificity in the lacZ gene of Escherichia coli.

The mutational specificities of various chemical mutagens were compared in isogenic E. coli strains with different DNA repair capabilities (wild-type, uvrA, umuC, and uvrA umuC) in a reversion assay employing a set of mutant lacZ genes that can detect two types of transitions, four types of transversions, and five kinds of specific frameshift events. A uvrA derivative was more sensitive than the wild-type strain to 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone for +1G, -1G, -2(C-G), +1A and -1A frameshifts, G.C-->A.T transitions, and G.C-->T.A transversions. In a uvrA background, G.C-->T.A transversions and +1G, +1A, and -1A frameshifts appeared to be umuC-dependent, while G.C-->A.T transitions were not. N-Ethyl-N'-nitro-N-nitrosoguanidine was more mutagenic in a uvrA background for five kinds of frameshifts and G.C-->A.T transitions, but not for G.C-->T.A, A.T-->C.G, and A.T-->G.C base substitutions. A.T-->C.G transversions were totally dependent on umuC gene function. For the investigation of mutational specificities induced by frameshift mutagens, an rfa mutation was additionally introduced. The rfa strain responded to 2-nitrofluorene, which induced primarily -2(C-G) frameshift mutations. In an rfa uvrA background, benzo[a]pyrene induced +1G, -1G, +1A, and -1A frameshifts. 2-Aminoanthracene induced +1G, -1G, and +1A, but not -1A, frameshifts, with -1G frameshifts predominating. Ethidium bromide induced only two types of frameshifts, -1G and +1A. Frameshifts induced by ICR-170 were independent of umuC gene function, while those by induced 1-nitropyrene were partly umuC-dependent.

Adenosine Triphosphatases↗
PubMed1994

Effects of supine and lateral recumbent positions on pulmonary venous flow in healthy subjects evaluated by transesophageal Doppler echocardiography.

OBJECTIVES: This study attempted to evaluate the effects of supine and lateral recumbent positions on pulmonary venous flow by transesophageal Doppler echocardiography in healthy subjects. BACKGROUND: Although transesophageal echocardiographic examination is usually performed with the patient lying in the left lateral decubitus or supine position, little attention has been paid to the effects of these positions on pulmonary venous flow. METHODS: We performed pulsed Doppler transesophageal echocardiography of the left and right pulmonary veins in 16 normal subjects as they lay in the left and right lateral decubitus and supine positions. RESULTS: Data are reported as mean value +/- SD. Adequate recordings were obtained in 12 subjects (75%). In the left pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow increased significantly in the left compared with the right lateral decubitus position (56 +/- 12 vs. 44 +/- 13 cm/s, p < 0.05, and 15 +/- 4 vs. 9 +/- 4 cm, p < 0.05, respectively). In the right pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow decreased significantly in the left compared with the right lateral decubitus position (38 +/- 10 vs. 48 +/- 9 cm/s, p < 0.05, and 9 +/- 2 vs. 12 +/- 2 cm, p < 0.05, respectively). There were no significant differences between positions in peak diastolic flow velocity, time-velocity integral of diastolic flow or peak velocity of flow reversal at atrial contraction. CONCLUSIONS: Pulmonary venous systolic peak velocities and time-velocity integrals of systolic flow increase when the pulmonary venous recording is from the recumbent subject's lower side. Therefore, the effects of position should be considered in evaluating left ventricular diastolic function by transesophageal Doppler echocardiography.

Adult↗
PubMed1994

Two significant aspects of microcystin-LR: specific binding and liver specificity.

Microcystin-LR is a unique and potent liver tumor promoter, belonging to the okadaic acid class compounds. Although microcystin-LR is a potent inhibitor of protein phosphatases 1 and 2A, as is okadaic acid, microcystin-LR has liver specificity dominance. Two significant aspects, specific binding and liver specificity of [3H]dihydromicrocystin-LR, a reduced form of microcystin-LR, were studied and compared with those of [3H]okadaic acid. [3H]-Dihydromicrocystin-LR had higher affinity for the receptors in both the particulate and cytosolic fractions of rat liver and various tissues than had [3H]okadaic acid. Intraperitoneal administration of [3H]dihydromicrocystin-LR into mice resulted in the highest uptake into the liver, 71.5 +/- 6.9% of the total administered radioactivity, whereas p.o. administration resulted in less than 1% uptake into the liver, suggesting that the mechanisms of the incorporation of microcystin-LR into the liver by i.p. and p.o. administrations are greatly different. The presence of associated forms of [3H]dihydromicrocystin-LR with macromolecules in the liver indicates a need for further investigation.

Animals↗