Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 883 records · Page 49Linked to original sources

PubMed1989

Serum-free, chemically defined medium to evaluate the direct effects of growth factors and inhibitors on proliferation and function of neonatal rat cardiac muscle cells in culture.

Neonatal rat cardiac myocytes were isolated and cultured to evaluate the effects of growth factors and inhibitors on proliferation, survival, and functions in a serum-free medium. Insulin and transferrin in MCDB 107 nutrient medium elicited DNA and protein synthesis in cells on a fibronectin-coated culture surface in serum-free medium. Insulin was most effective on both DNA and protein synthesis in serum-free culture conditions. The serum-free, hormone-supplemented medium eliminated the contamination of noncardiac myocytes and supported the long-term survival (over 18 d) of cardiac myocytes. Dexamethasone was required to induce optimal contractility with or without insulin and transferrin. Serum contained both negative and positive effectors of DNA and protein synthesis of the cardiac myocytes. Concentrations of serum (above 5%) inhibited DNA and protein synthesis. Low density lipoprotein (LDL) accounted in part for the inhibitory activity. The serum-free culture system provides a useful model to elucidate the role of hormones, growth factors, and drugs in heart cell regeneration and function.

Animals↗

PubMed1989

Immunoelectron microscopic localization of actin in normal and cholestatic rat hepatocytes.

The immunoelectron microscopic localization of actin in hepatocytes was studied in normal, common bile duct-ligated, and phalloidin treated rats. We used the low temperature embedding procedure with Lowicryl K4M and protein A-gold technique was applied to demonstrate the localization of actin. The tissues embedded in Lowicryl K4M at low temperature provided good preservation of ultrastructure and antigenicity of actin. In control rats bile canaliculi were clearly visualized and most of the gold particles were observed on the bile canalicular microvilli, at the pericanalicular ectoplasm, at the cell border, and on the sinusoidal microvilli. In common bile duct-ligated rats and phalloidin treated rats, pericanalicular ectoplasm was thickened and many gold particles were seen there.

Actins↗

PubMed1989

Differences in the influence of diet on hepatic glutathione S-transferase activity and glutathione content between young and old C57 black female mice.

The effect of a protein-free diet (PFD) on hepatic activity of glutathione S-transferase (GST) and hepatic content of total glutathione (GSH) was examined in young (9-month-old), middle-aged (17-month-old) and old (27-month-old) C57BL/6CrS1c female mice. There were no significant differences in the control values of GSH or of enzyme activity for four of five substrates among young, middle-aged, and old animals fed normal diet (ND) only. Both GSH and GST activity were significantly decreased by the 7-day PFD in both young and old groups but the decrement was generally greater in old mice. After a 2-3-day refeeding of ND, young mouse enzyme activities were significantly higher than control (basal) values for all five substrates, whereas old mouse values were still significantly lower than corresponding control values. There was no overshooting of GSH levels after refeeding of ND in either young or old animals. This study indicates that an age difference in this detoxification system can be clearly demonstrated in the hepatic response to PFD feeding and especially to ND refeeding, despite the enzymes' stable basal activities with aging.

Aging↗

PubMed1989

Three-year prospect of patients with common epithelial carcinoma of the ovary.

In order to forecast the survival of patients, we collected 417 cases of common epithelial carcinoma of the ovary as a population for this study, then selected 141 cases who had survived more than 3 years and 131 cases who had died within 3 years as a sample of statistical inference. The sample was computerized inputting 25 factors which were obtained mainly on the first surgery. We selected 8 factors with 46 items considering their weight to forecast the prognosis on convenience. The selection of factors was carried out by following three basic principles. First, we selected factors that retained high partial correlation coefficients. Second, we selected factors which did not overlap each other in their contents. Third, we selected factors which were not decided intentionally. Accordingly, the score for forecasting the 3-year survival of patients with ovarian carcinoma was framed. The correct discrimination rate of the score when it was judged at the 0 point was 86.8% in the sample group. However, in the sample group outside the population, it was 83.1%.

Adult↗

PubMed1989

Age-related differences in the coordination disturbance and anticonvulsant effect of oxazepam in mice.

The effects of oxazepam on coordination and maximal seizure were compared between young (6-month-old) and old (24-month-old) BDF1 mice by using a rotorod test and a pentylenetetrazole (PTZ)-induced seizure test, respectively. The apparent sensitivity to oxazepam's anticonvulsant effect, as examined by its effect on PTZ-induced maximal seizure, was increased in old animals of both sexes in comparison to young ones. The effect of oxazepam on coordination was also significantly greater in old male mice as compared with the young. The results of the present study, together with our past observations on other anticonvulsants such as phenytoin and phenobarbital, strongly suggest that the anticonvulsant effect, as well as the effect on coordination, in mice generally increases with age.

Age Factors↗

PubMed1989

Elevation of a novel pituitary protein (7B2) in the plasma in small cell carcinoma of the lung.

7B2 is a new protein isolated from human pituitary glands and distributed widely, particularly with high concentrations in the neuroendocrine tissues in the rat. We measured plasma 7B2 concentrations in 333 normal subjects, 20 patients with benign pulmonary disease and 111 patients with primary lung cancer (21 small cell carcinoma, 90 non-small cell carcinoma). A normal range for plasma 7B2 concentrations was defined as less than the mean + 3 S.D. value (110 pg/ml) based on plasma 7B2 concentrations in 333 normal subjects. Elevation of the plasma 7B2 concentration over the normal range was observed in 15 of 21 patients (71.4%) with small cell carcinoma, eight of 90 (8.9%) with non-small cell carcinoma and four of 20 (20%) with benign pulmonary disease. Plasma 7B2 concentrations correlated with the clinical course on chemotherapy in some patients with small cell carcinoma. Immunocytochemical studies revealed numerous 7B2-positive cells in the small cell carcinoma specimen, while 7B2 staining was not observed in the non-small cell carcinoma and the normal lung specimens. These findings suggest that 7B2 is secreted by the small cell carcinoma of the lung, which caused elevation of plasma 7B2 in these patients. 7B2 might be a possible plasma tumor marker for the small cell carcinoma of the lung.

Adult↗

PubMed1989

Corticotrigeminal motor pathway in the rat--II. Anterio- and retrograde HRP labeling.

1. Horseradish peroxidase (HRP) injection into the rat cortical jaw motor area (JMA) disclosed direct projection fibers in and around the motor trigeminal nucleus (MTN), primarily contralaterally. 2. Descending axons were found in the ventromedial half of the cerebral peduncle and MTN-projecting axons were concentrated near the descending facial nerve root. 3. HRP injection into the peduncle could label 1257 cells in the JMA, 128 cells in the taste area and 1409 cells in the neck-forelimb motor area ipsilaterally. 4. Some MTN-terminated axons could be traced from the peduncle in serial sections.

Animals↗

PubMed1989

Insulin-like growth factor-I, GH, insulin and glucagon concentrations in bovine colostrum and in plasma of dairy cows and neonatal calves around parturition.

1. The IGF-I concentrations in colostrum on days 1 and 2 after parturition were higher than those in cow and neonate plasma. 2. The modest increase in GH concentrations in cow plasma around parturition would not be enough to stimulate IGF-I release by tissues. 3. The concentrations of insulin, GH and glucagon in colostrum were substantially lower than those in plasma.

Animals↗

PubMed1989

Corticotrigeminal motor pathway in the rat--I. Antidromic activation.

1. The rat corticotrigeminal motor pathway was electrophysiologically investigated. 2. Fifty-one cortical neurons were antidromically activated by stimulation of the contralateral motor trigeminal nucleus (MTN). 3. Twenty-eight of the neurons were examined to see whether they were pyramidal tract (PT) neurons and seven were the PT neurons. 4. Forty peduncular axons were antidromically activated by stimulation of the contralateral MTN and eight of them were the PT axons. 5. Most MTN projecting axons showed slower conduction velocities than their stem anons.

Animals↗

PubMed1989

Effect of centrophenoxine and BCE-001 treatment on lateral diffusion of proteins in the hepatocyte plasma membrane as revealed by fluorescence recovery after photobleaching in rat liver smears.

The average lateral diffusion coefficient of proteins (D) in the cell membrane of hepatocytes has been measured in liver smears by fluorescence recovery after photobleaching (FRAP), based on the so-called peroxide-induced autofluorescence (PIAF) deriving from the oxidation of riboflavin bound to membrane proteins. It has been previously shown that D displays a significant negative linear age correlation. The in vivo effects of two drugs were tested on this parameter. Young (2.7 months) and old (24-26 months) male rats received centrophenoxine (CPH) or a new drug (BCE-001) by either intraperitoneal (i.p.) injection or per os through a gastric tube for 26 to 42 days. D was measured on a double-blind basis in the hepatocyte plasma membrane of treated and control groups. The CPH and BCE-001 treatments did not affect the value of D in the young rats. However, the latter drug increased their growth rate. An increase of D in old animals was induced by treatment with either drug. When the drug effects in old rats were compared, BCE-001 proved to be more efficient than CPH, and at the same time was able to significantly retard the age-dependent loss of body weight characteristic of these animals at the age of approximately 2 years. Our results are in good accord with the predictions of the membrane hypothesis of aging as regards the role of properly placed OH. free radical scavengers in the improvement of membrane and overall cell function.

Aging↗

PubMed1989

Interaction of intermediate filaments with nuclear lamina and cell periphery.

Ultrastructural observations of the cytoskeleton suggest that the connection of the intermediate filaments (IFs) to actin microfilaments (MFs) at the plasma membrane and the nuclear lamina inside the nuclear membrane link signals received at the cell periphery to the nucleus. When these connections are viewed in three dimensions using detergent extracted cytoskeletal preparations from tissue cultures or slices made from tissue, the IFs are seen to run without interruption from the cell periphery to the nucleus and back. The IFs form side to side connections with the nuclear lamina and pore complexes. The nucleus and the centrioles are supported and held suspended in these extracted cells where all organelles and cytosol have been removed. The IFs are particularly dense in the ectoplasm where they form a sheet and provide the scaffolding which maintains the shape of the extracted cells. The IFs in the ectoplasm are attached to desmoplakin at cell-cell desmosome adhesions and to MFs where the cells are attached to the fibronectin substratum possibly through integrin linkages at adhesion plaques. This was graphically shown by immunogold labelling of IF cells treated with nickel. In this way, it was possible to visualize the loss of the cell-cell connections at desmosomes and the disruption of the IF-MF connections in the ectoplasm. The MFs after losing their connections with the IFs, redistribute to cover the entire cell periphery. The nickel treatment of primary liver cell cultures lead to the loss of several functions including formation of the bile canaliculus, the ability to secrete fluorescein diacetate and the ability to take up horseradish peroxidase (HRP) by endocytosis. These observations support the conclusion that the IF-MF connections at the cell periphery provide both structural and functional polarity of the liver cells including uptake and secretion and the formation of bile canaliculi.

Animals↗

PubMed1989

Age-dependence of the lateral mobility of proteins in the plasma membrane of hepatocytes of C57BL/6 mice: FRAP studies on liver smears.

Protein lateral diffusion in hepatocyte membranes was measured in 23 male and 16 female C57BL/6 mice in four groups of age 5 to 32 months by means of fluorescence recovery after photobleaching (FRAP). The peroxide-induced autofluorescence (PIAF) in H2O2 treated liver smears is due to the oxidation of flavins bound uniformly to all proteins of the cell membrane, i.e., an average lateral diffusion constant (D) of those proteins can be measured. D showed a negative linear age-correlation in both sexes: D male = (2.81 - 0.016X)10(-10), and D female = (2.67 - 0.020X)10(-10) cm2/sec, (r greater than 0.94), where X is the age in months. Sex differences are significant (p less than .001) in the intercept. Fractional recovery did not prove to be age-dependent; it was, on average, 91% in males and 100% in females. The findings agree well with the previously obtained data on Fischer 344 and Wistar rats, and strengthen the gerontological relevance of D.

Aging↗

PubMed1989

Lymphocyte infiltration into cerebellum in transgenic mice carrying human IL-2 gene.

We created transgenic mice with an intact human genomic interleukin-2 gene (gIL-2) or a mouse metallothionein-I promoter-human IL-2 chimeric gene (MTgIL-2). Nine (2 gIL-2 and 7 MTgIL-2 transgenics) out of 12 transgenic mice which were obtained independently had motor ataxic symptoms. All transgenic offspring of the symptomatic founders showed the same symptoms as their transgenic parents. Morphological examination demonstrated perivascular lymphocyte accumulation in the cerebellar meninx which was followed by increased cell infiltration of neutrophils and monocytes in the destructive cerebellum of all transgenic mice. These findings suggest that the lymphocyte infiltration in the cerebellum is caused by the specific effect of the exogenously introduced human IL-2 gene.

Animals↗

PubMed1989

N-acetylgalactosaminyl disaccharide terminals contained in presumed carbohydrate epitopes specific to sea-squirt allergy.

Using the methods of methylation/GLC, MS, and 1H-NMR analyses, a disaccharide structure of GalNAc alpha 1----2Fuc1---- was identified as one of the major structural units at non-reducing terminals of a highly branched and N-glycosidically linked carbohydrate on an allergenically active glycopeptide, Gp-2 (Mr ca. 8,000). Gp-2 was one of the major fractions in the Pronase digest of a sea-squirt antigen, Gi-rep, and is capable of eliciting the skin reaction specific to patients with sea-squirt allergy similarly to Gi-rep. An additional disaccharide structure of GalNAc1----(3/4)HexNAc1---- was also expected as the other major non-reducing terminal unit, though the anomeric configuration of the terminal GalNAc could not be identified. As Gp-2 carbohydrate was found to contain 3 mol each of the two types of terminal GalNAc-containing units, both were nominated as possible components of the IO4- oxidation-sensitive epitopes which are responsible for the allergenic activity in Gp-2 and its mother antigen, Gi-rep. A few moles of Fuc and Gal were also detected as minor non-reducing terminals in addition to the 6 mol of the GalNAc-containing units.

Acetylglucosamine↗

PubMed1989

A role of melatonin in the initial stage of photoperiodism in the Japanese quail.

To estimate whether melatonin is involved in gonadal activity in the male quail, the dynamics of plasma melatonin at an early stage of the photoperiodic response were investigated. Nocturnal levels of melatonin were manipulated by treatment with anti-melatonin (anti-M). By means of 4 additional hours of photic stimulation of the brain (provided by a red light-emitting diode inserted through the back of the head) after the environmental lights (8L:16D, lights-on, 1000 h) were turned off, the elevation of levels of melatonin after lights-off was significantly suppressed on Days 1 and 2 (p less than 0.01); after 5 days of brain-lighting, gonadal growth first became noticeable. However, 4 h of brain-lighting before lights-on elicited no change in levels of melatonin or in gonadal growth. The injections of anti-M just before lights-off (at 1800 h) for the first 3 days caused significant gonadal growth (p less than 0.01), whereas injections at 2200, 0200, or 0600 h were without effect. In addition, 4 h of brain-lighting before lights-on became gonadostimulatory (p less than 0.01) when it was accompanied by the injection of anti-M at 1800 h, but remained without effect when anti-M was injected at 0600 h. These results suggest that melatonin is involved in the initial stage of photoperiodism in birds, and the timing of suppression of the elevation of melatonin levels is critical in gonadal development.

Animals↗

PubMed1989

Congenital absence of the portal vein.

A 14-year-old girl presented at the hospital after discovering an abdominal tumor. CT scan and ultrasonography indicated a hepatic tumor and also revealed the absence of the portal vein. The patient was admitted to excise the hepatic tumor. It was found that the venous blood from the small intestines flowed into the left renal vein and then emptied directly into the inferior vena cava. A tumor extending from the right lobe through the middle portion of the liver was excised. The postoperative course was satisfactory and marked regeneration of the residual hepatic tissue was observed. Also the blood level of ammonia in the superior mesenteric vein was low, approximately 120 micrograms/dl, compared to the normal value of 350 micrograms/dl in the portal vein. This low blood level may indicate the presence of some homeostatic control mechanism.

Adolescent↗

PubMed1989

Erythroderma with generalized lymphadenopathy induced by phenytoin.

A 40-year-old man developed a generalized erythematous rash, fever, and systemic lymphadenopathy after treatment for two months with anticonvulsants including phenytoin. Laboratory examinations revealed increased white blood cell counts with eosinophilia, abnormal liver function, and increased gammaglobulin levels. A lymphocyte stimulation test showed a significant stimulation index for phenytoin. Skin biopsy findings were nonspecific cellular infiltrates in the upper dermis whereas in lymph nodes the normal architecture was replaced by massive cellular infiltrates consisting largely of lymphocytes, immunoblasts, and eosinophils suggesting a pattern of phenytoin lymphadenopathy. No malignant changes were noted. Phenytoin was discontinued and after a two-month treatment with oral corticosteroids, all manifestations had nearly subsided. However, the patient should be carefully followed up since phenytoin occasionally induces lymphoproliferative states including malignant lymphoma even after cessation of the medication.

Adult↗

PubMed1989

Identification of species and capsular types of Klebsiella clinical isolates, with special reference to Klebsiella planticola.

In the 77 reference strains for Klebsiella K types, there are 17 strains (22.1%) of Klebsiella planticola, 6 strains (7.8%) of Klebsiella oxytoca, 1 strain (1.3%) of Klebsiella terrigena, and 53 strains (68.8%) of Klebsiella pneumoniae. The species K. planticola, which was originally isolated from botanical and aquatic environments and hence thus named, was also identified at high incidence (81 strains, 18.5%) among the 439 recent clinical isolates of Klebsiella species. Among these K. planticola strains of hospital origin, 52 (64%) were isolated from sputum, 17 (21%) from urine, and the remaining 12 (15%) from other sources. The capsular types of these isolates were determined by the gel precipitation reaction. Seventy of 81 K. planticola isolates (86.4%) were typable by antisera to Klebsiella reference strains for K types and the K types of the clinical isolates distributed to 35 kinds of K types. The proportion of typable strains among clinical isolates of K. planticola was very similar to those in K. pneumoniae (87.5%) and K. oxytoca (86.0%).

Antigens, Bacterial↗