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Biomedical subjects

R Nakayama

Publications and source records attributed to R Nakayama.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Correlations between blood pressure, left ventricular hypertrophy, and left ventricular diastolic function in hypertensive patients].

We examined the relationship of hypertension to left ventricular hypertrophy (LVH) and left ventricular diastolic function by ambulatory blood pressure monitoring device and echocardiography. We studied 36 untreated hypertensive non-diabetic patients (16 males and 20 females) whose casual systolic blood pressure (CSBP) and/or diastolic blood pressure (CDBP) were higher than 140 mmHg and 90 mmHg, respectively. All patients were less than 65 years of age without organic heart disease. Resting systolic and diastolic blood pressures (RSBP, RDBP) were measured after lying in a supine position for 30 min by the auscultatory method. Ambulatory blood pressure was measured every 30 or 60 min for 24 hours by Colin ABPM 630, and the mean 24-hour ambulatory systolic and diastolic blood pressures (ASBP, ADBP) and the systolic and diastolic hyperbaric indices (SHI, DHI) were obtained. The left ventricular mass index (LVMI) was obtained as an indicator of LVH by M-mode echocardiography. The ratio of peak velocity of mitral inflow caused by atrial contraction to that of rapid inflow (A/R) was obtained as an indicator of the LV diastolic function by Doppler echocardiography. The coefficients of correlation between BP and the LVMI, and the A/R were determined. There were significant positive correlations between the LVMI and ASBP (r = 0.51, p < 0.005), the SHI (r = 0.49, p < 0.005), CSBP (r = 0.47, p < 0.01) and RSBP (r = 0.41, p < 0.05), however, there were no significant correlations between the LVMI and ADBP, the DHI, CDBP, RDBP and age. There were significant positive correlations between the A/R and ADBP (r = 0.44, p < 0.01), age (r = 0.40, p < 0.02), CSBP (r = 0.38, p < 0.05) and RDBP (r = 0.38, p < 0.05), however, no significant correlations between the A/R and ASBP, the SHI, DHI, RSBP and CDBP. Only a weak correlation was observed in all subjects between the LVMI and A/R, which was slightly improved by use of > 90 mmHg CSBP readings (r = 0.32). It was concluded that LVH is related mainly to continuous systolic hypertension, and that LV diastolic dysfunction is related mainly to continuous diastolic hypertension. Therefore, it was suggested that LVH and LV diastolic dysfunction in hypertensive patients are caused by different mechanisms.

Adult↗
PubMed1990

Solution hybridization quantitation of G6PD mRNA in rat epididymal fat pads.

A solution hybridization assay is systematically characterized and used to quantitate glucose-6-phosphate dehydrogenase (G6PD) mRNA from epididymal fat pads in fasted and glucose-induced rats. G6PD mRNA and specific activity increase 9-fold and 2-fold, respectively. The 9-fold increase in G6PD synthesis reported previously (Wolfe et al. (1979) Biochem. Biophys. Res. Commun. 89, 108-115) can, therefore, be accounted for by the increase in G6PD mRNA. This solution hybridization assay is sensitive enough to quantitative levels of G6PD mRNA in total liver RNA from a fasted rat, one of the least abundant sources of this mRNA. It can, therefore, be used to answer several questions about the regulation of G6PD synthesis in rat tissues. Preliminary results suggest that the dietary regulation of G6PD mRNA in rat liver is much larger than previously reported.

Adipose Tissue↗
PubMed1990

Quantitation of glucose-6-phosphate dehydrogenase mRNA by solution hybridization: correlation with rates of synthesis.

Rat liver glucose-6-phosphate dehydrogenase (G6PD) is one of several proteins involved in lipid metabolism whose synthesis is regulated by diet. In experiments reported here, rats were fasted or fed diets until a new steady state level of G6PD was produced. Livers were used to measure G6PD activity, synthesis and mRNA simultaneously. Since accurate quantitation of G6PD mRNA by Northern blots was found to be difficult in noninduced animals a new solution hybridization assay was also used. Noninduced rats have approx. One molecule of G6PD mRNA per liver cell. Changes in G6PD mRNA are larger than previously reported and, at the steady state, can completely account for the 33-fold change in G6PD activity and synthesis when fasted rats are refed a high carbohydrate diet. In contrast, a high fat carbohydrate-free diet does not increase G6PD mRNA and dibutyryl cAMP lowers G6PD mRNA. Since changes in G6PD synthesis and activity are closely correlated, degradation of G6PD is not significantly regulated.

Animals↗
PubMed1990

Isolation and characterization of three distinct 34 kDa EDTA-extractable proteins from bovine lens.

EDTA-extractable protein (EEP) is known to be a major lens membrane protein with a molecular mass in the range 32 kDa to 38 kDa, and is also known to bind to the lens membrane and phospholipid-containing liposomes in a calcium-dependent manner. Recent results (Russell, P., Zelenka, P., Martensen, J., and Reid, T.W. (1977) Curr. Eye Res. 6, 533-538) on antibody cross-reactivity have demonstrated that a 34-35 kDa component of EEP is identical to calpactin I (lipocortin II). In this study, we have identified and purified three distinct 34 kDa components of EEP (designated as EEP-34A1, EEP-34A2 and EEP-34B) from bovine lens that inhibit phospholipase A2 activity. These proteins bind to phospholipid-containing liposome and F-actin in a calcium-dependent fashion. Two-dimensional electrophoresis demonstrates that the three proteins were distinct from one another. However, immunochemical studies and one-dimensional peptide mapping indicate that EEP-34A1 and EEP-34B are very similar. Our results also indicate that EEP-34A1 is very similar to calpactin II and that EEP-34A2 corresponds to calpactin I. The bovine lens 34-35 kDa component of EEP is a mixture of proteins rather than a single protein.

Actins↗
PubMed1990

Identification of the 32 kDa components of bovine lens EDTA-extractable protein as endonexins I and II.

EDTA-extractable protein (EEP) is a mixture of major lens membrane proteins with molecular masses ranging from 32 kDa to 40 kDa. These bind to the lens membrane in a Ca2(+)-dependent manner. In the present study we have identified and purified two distinct 32 kDa components of EEP (designated as EEP 32-1 and EEP 32-2) from bovine lens that inhibit phospholipase A2 activity. Both EEP 32-1 and EEP 32-2 bind to phospholipid-containing liposomes and actin filaments in a Ca2(+)-dependent fashion. Immunochemical studies and two-dimensional electrophoreses demonstrate that the two proteins are distinct from one another. Both EEP 32-1 and EEP 32-2 are clearly different from calpactin (lipocortin) or its proteolytic fragments because they did not react with anti-[human placenta calpactin (lipocortin)] antibody. Our results also indicate that EEP 32-1 is very similar to endonexin I and that EEP 32-2 corresponds to endonexin II.

Actins↗
PubMed1990

Exercise thallium scintigraphy in aortitis syndrome (Takayasu's arteritis).

It is important for patient management to evaluate coronary arterial involvement in aortitis syndrome. Twenty one cases of aortitis syndrome who experienced chest pain were examined using exercise thallium scintigraphy. The patients were divided into four groups according to the angiographic findings. There were: five patients with left main coronary arterial involvement (group A), four with left or right coronary arterial involvement (group B), nine with aortic regurgitation (group C), and three with pulmonary arterial involvement (group D). In group A and B, all patients had positive ECGs and thallium perfusion defects. Group A patients showed extensive anterolateral perfusion defects, which were compatible with left main coronary arterial involvement. Group C and D patients, who had normal coronary arteries, showed no remarkable perfusion defects although five had positive ECG findings. Thus, the sensitivity and specificity of exercise scintigraphy for detection of myocardial ischemia were 9/9 and 12/12, while those of stress ECG were 9/9 and 7/12 (58%), respectively. It is recommended that exercise thallium scintigraphy be used for detecting clinically occult but significant coronary arterial involvement in aortitis syndrome with chest pain.

Adult↗
PubMed1990

When should antibody screening tests be done for recently transfused patients?

The American Association of Blood Banks (AABB) requires that blood samples used for pretransfusion testing of recently transfused (or pregnant) patients must be obtained within 3 days of scheduled transfusions. This requirement, which became effective in July 1988, amended Standard G2.000 of the AABB, which previously required that pretransfusion testing must be done on blood samples obtained within 2 days of scheduled transfusions. The present study was designed to estimate the risk associated with adopting the amended version of Standard G2.000. Sixty patients who developed significant unexpected alloantibodies after transfusion were studied retrospectively. Thirteen of the 60 patients were found to have newly detectable antibodies within 83 hours of a sample reported to be negative for the new antibody. Had the amended version of Standard G2.000 been in effect, the detection of some of these antibodies might have been delayed up to 24 hours. It was estimated that the implementation of the new AABB requirement at the authors' institution could potentially place about 1 in 3000 transfused patients at risk for an acute or delayed hemolytic transfusion reaction.

Blood Group Incompatibility↗
PubMed1990

Prevalence and risk factors of varicose veins in Japanese women.

The prevalence and risk factors of varicose veins in Japan were investigated in 541 Japanese women. Varicose veins were defined as any dilated, tortuous, and elongated veins of the lower extremity and classified into four types. The total prevalence rate was 45%. Saphenous type was observed in 22%, segment type in 35%, reticular type in 28%, and web type in 16%. Varicose veins in Japan seem to be less common than in the United States and Europe but more prevalent than in Africa. Concerning risk factors for varices, age, sex, heredity, and childbirth were related to the incidence of varicosities, as reported by others. However, these risk factors were shown to differ according to type of varicose veins.

Adolescent↗
PubMed1990

[Constituents of Berchemia racemosa Sieb. et Zucc].

Mearnsitrin-3-O-alpha-L-rhamnoside, myricitrin, narcissin and other flavones were isolated together with phenolic carboxylic acids from the leaves of Berchemia racemosa Sieb, et Zucc. From the wood of this plant, flavanones, flavanonols, phenolic carboxylic acids, (-)-catechin and other were isolated, and identified.

Drugs, Chinese Herbal↗
PubMed1989

Presence of 1-O-alk-1'-enyl-2-O-acetyl glycerophosphocholine (vinyl form of PAF) in perfused rat and guinea pig hearts.

1-O-Alk-1'-enyl-2-O-acetyl-glycerophosphocholine (vinyl form of PAF) was found with PAF in perfused rat and guinea pig hearts. The main molecular species of the vinyl form of PAF, after separation by reverse phase HPLC, were identified as 1-O-hexadec-, -octadec-, and -octadecen-1'-enyl-2-O-acetyl-GPCs (16:0, 18:0, and 18:1 vinyl forms of PAF) by mass spectrometry. The amounts of the predominant 16:0 species in rat and guinea pig hearts, respectively, were 46.4 and 22.5 ng per mg lipid-phosphorus of the original heart phospholipids.

Animals↗
PubMed1989

[Research in similarities between EEP34 and lipocortin].

EDTA-extractable protein (EEP) is a major extrinsic protein of lens fiber membrane. The EEP of calf lens separated three major bands by SDS-PAGE, and the molecular weights of these major bands were 34 kilodalton (kd.), 33 kd. and 32 kd. Combination of EEP with F-actin and some kinds of phospholipid containing liposomes depends on Ca2+. In two-dimensional gel electrophoresis, some spots of the calf-EEP partially overlapped with spots of lipocortin, which is a substrate for epidermal growth factor receptor/kinase and an inhibitor of phospholipase A2. The 34 kd. protein of the EEP cross-reacted to the antibody prepared against lipocortin of pig's aorta: These results suggest the important function of EEP in lens.

Animals↗
PubMed1989

[Biochemical and immunological properties of EEP 32 kd protein].

EDTA-extractable protein (EEP) is a major extrinsic protein of lens membrane. EEP is composed of two major polypeptides on SDS-PAGE with apparent molecular weights of 32 kilodaltons (kd) and 34 kd. Recently it has been reported that the 34 kd protein of the EEP cross-reacted with the antibody prepared against lipocortin, an inhibitor of phospholipase A2. We have purified and characterized the 32 kd protein of the EEP (EEP 32). Crude EEP of bovine lens was applied to a Q-Sepharose column and eluted with a linear gradient system composed of 0-0.7 M NaCl. The EEP 32 was discreted at salt concentrations of approximately 0.1-0.25 M (EEP 32-A) and 0.35-0.4 M (EEP 32-B). Both EEP 32-A and EEP 32-B interact with phospholipid and F-actin in a Ca2+-dependent manner as lipocortin. Furthermore, the EEP 32-A, a major component of the EEP 32 purified by hydroxyapatite chromatography and gel filtration, inhibited phospholipase A2 activity more than lipocortin. On Western blot analysis, the 32 kd lipocortin-like protein of human placenta showed cross-reactivity to EEP 32-B, but not EEP 32-A. These results suggest that EEP 32 contains two lipocortin-like proteins differing in antigenicity and isoelectric points.

Animals↗
PubMed1989

[Biochemical and immunological properties of 34kDa EDTA-extractable protein (EEP34k)].

It has been reported that the 34kDa protein of EDTA-extractable protein (EEP34k) cross-reacted with lipocortin antisera. The lipocortins are a family of proteins that have been reported to inhibit phospholipase A2. Previously, we purified two proteins from EEP34k by anion-exchange chromatography, and referred to them as 34k (A) and 34k (B). On Western-blot analysis, two proteins showed cross-reactivity to both lipocortin I and lipocortin II. In this study, four proteins (34k (A)1, 34k (A)2, 34k (B)1, 34k (B)2) were isolated from 34k (A) and 34k (B), on a cation-exchanged chromatography. By peptide mapping, immunological analysis and SDS/PAGE, we confirmed that 34k (A)1 and 34k (B)2 were identified proteins and these were called lipocortin I, and that 34k (A)2 was lipocortin II. It is concluded that at least two lipocortins, I and II are present in EEP34k. We also observed the presence of phospholipase A2 inhibitory activity in both 34k (A) and 34k (B).

Animals↗
PubMed1989

Regulation of apolipoprotein E synthesis and mRNA by diet and hormones.

Rats were fasted or fasted and refed simple purified diets so the effects of individual carbohydrates or fats could be studied. Freshly isolated hepatocytes from these animals were used to measure both apoE synthesis and mRNA levels so any changes in apoE synthesis that might occur without changes in its mRNA could be detected. Some of these experiments were done with both sexes. Both fasting and fasting and refeeding a 60% glucose fat-free diet significantly increased spoE synthesis. However, cyclic AMP is not likely to rapidly mediate the effect of fasting since dibutyryl cAMP slightly lowered (rather than increased) apoE synthesis and mRNA when injected into rats for 4.5 h. Dietary fat had no effect either in the absence of carbohydrate or when consumption of carbohydrate was constant in pair-fed rats. ApoE mRNA levels remained normal for 4 days in primary hepatocytes cultured in medium that had only amino acids as an energy source. Added hormones or fructose had no significant effect. Thus, only fasting and fasting and refeeding glucose were able to significantly change apoE synthesis or mRNA levels. Synthesis of apoE may be regulated to increase when apoE is secreted with very low density lipoprotein or when apoE in secreted high density lipoprotein is needed to acquire cholesteryl esters for the synthesis of bile salts and acids by liver.

Animals↗
PubMed1989

[A case of pulmonary neurilemmoma].

Intrapulmonary or bronchial neurilemmoma are rare neoplasms and there have been only 29 cases reported in the foreign and domestic literature. We experienced a case of neurilemmoma of the right upper lobe in a 41-year-old male. The patient had no complaint but, a small coin lesion (1.2 x 1.4 cm) was pointed out by chest X-ray examination. The tumor was diagnosed as neurilemmoma by transbronchial lung biopsy and a right upper lobectomy was performed. He has remained asymptomatic in the 18 months after operation.

Adult↗
PubMed1988

1-O-hexadec-1'-enyl-2-acetyl-sn-glycero-3-phosphocholine and its biological activity.

1-O-Alk-1'-enyl analog of platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, alkylacetyl-GPC) was prepared semi-synthetically from choline plasmalogens of beef heart muscle. The main compound was identified mass spectrometrically as 1-hexadec-1'-enyl-2-acetyl-sn-glycero-3-phosphocholine (16:O alk-1'-enylacetyl-GPC, 16:O vinyl form of PAF) and its platelet aggregation activity was about one-fifth of that of the corresponding 16:O alkylacetyl-GPC. The irreversible platelet aggregation activity induced by 5X10(-10) M 16:O alk-1'-enylacetyl-GPC was completely inhibited by 5X10(-7) M CV-3988 and 1X10(-7) M L-652, 731, specific PAF antagonists, and more than 99% of the activity was also lost by acid treatment. The hydrogenated product, alkylacetyl analog, showed quite same activity as that of authentic 16:O alkylacetyl-GPC. The platelets desensitized with 16:O alkylacetyl-GPC and with 16:O alk-1'-enylacetyl-GPC were not aggregated with 5X10(-10) M 16:O alk-1'-enylacetyl-GPC, suggesting that alk-1'-enylacetyl-GPC occupied the same receptor site of alkylacetyl-GPC.

Animals↗
PubMed1988

Acyl type platelet-activating factor in normal rat uterus determined by gas chromatography mass spectrometry.

1-Fatty acyl-2-acetyl-sn-glycero-3-phosphocholine (1-fatty acyl-2-acetyl GPC, acyl type platelet-activating factor (PAF) was found in normal rat uterus without addition of any exogenous stimuli and identified as 1-palmitoyl, 1-oleoyl and 1-stearoyl species by gas chromatography/mass spectrometry coupled with selected ion monitoring (SIM). The main species was the 1-palmitoyl species. The ions used for SIM were chosen on the basis of the acetyl and fatty acyl moieties and molecular weight. The amount of 1-fatty acyl-2-acetyl GPC was significantly more than that of PAF (1-fatty alkyl-2-acetyl GPC, AGEPC), and the ratio of 1-palmitoyl-2-acetyl GPC to 1-0-hexadecyl-2-acetyl GPC was about 4.5:1 in normal rat uterus.

Animals↗