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Biomedical subjects

K Murakami

Publications and source records attributed to K Murakami.

At least 1,153 records · Page 64Linked to original sources
PubMed1983

Cloning and sequence analysis of cDNA for human renin precursor.

The primary structure of human renin precursor has been deduced from its cDNA sequence. A library of cDNA clones was constructed from human kidney poly(A)+ RNA by applying the vector/primer method of Okayama and Berg. The library was screened for human renin sequences by hybridization with the previously cloned mouse renin cDNA. Of the 240,000 colonies screened, 35 colonies that were positive for hybridization were isolated. Two recombinant plasmids containing long inserts of about 1,300 and 1,600 base pairs were selected for sequence analysis. The amino acid sequence predicted from the cDNA sequence shows that the human renin precursor consists of 406 amino acids with a pre and a pro segment carrying 20 and 46 amino acids, respectively. A high degree of sequence homology was found upon comparison of the mouse and human renins. Close similarities were also observed in the primary structures of renin and aspartyl proteinases that have known three-dimensional structures, suggesting a similar tertiary structure for renin.

Amino Acid Sequence↗
PubMed1983

The inhibitory effects of N2-dansyl-L-arginine-4-t-butylpiperidine amide (TI233) on contraction of vascular and intestinal smooth muscle.

Effects of N2-dansyl-L-arginine-4-t-butylpiperidine amide (TI233) on the contractions in vascular and intestinal smooth muscles were examined. High K-induced sustained contractions in the smooth muscles were inhibited by TI233 with an IC50 of 2.1 X 10(-5) M for rabbit aorta and 3.6 X 10(-6) M for guinea-pig taenia coli in a solution containing 1.5 mM Ca. Initial transient contraction induced by K in taenia coli was less sensitive to the inhibitory effect of TI233. When the Ca concentration in the medium was decreased to 0.3 mM, the concentration-inhibition curves for TI233 shifted to the left in both aorta and taenia coli. Increasing the Ca concentration to 7.5 mM shifted the curve to the right in the aorta. TI233 also inhibited the noradrenaline-induced contraction in the aorta (IC50 = 2.1 X 10(-5 M). In a hypoxic solution without added glucose, the inhibitory effect of TI233 on the K-induced contraction in aorta was augmented. In the presence of high concentrations (40 mM) of glucose in hypoxia, TI233 did not inhibit the noradrenaline-induced contraction of the aorta. Hypoxia and a high concentration of glucose also decreased the inhibitory effect of TI233 on the K-induced contraction in taenia coli. TI233 inhibited the K-induced increase in cellular Ca content measured by a modified lanthanum method. TI233 decreased oxygen consumption and ATP content of resting and K-stimulated aorta and taenia coli. It was concluded that TI233 inhibits the vascular and intestinal smooth muscle contraction by a Ca antagonistic action and also by inhibition of aerobic metabolism.

Adenosine Triphosphate↗
PubMed1983

Characterization of rat hypothalamic corticotropin-releasing factor by reversed-phase, high-performance liquid chromatography with synthetic ovine corticotropin-releasing factor as a marker.

Reversed-phase, high-performance liquid chromatography (HPLC) was carried out to characterize rat hypothalamic corticotropin-releasing factor (CRF) using synthetic ovine CRF as a marker. Samples were injected onto a stainless steel column (4 X 250 mm) packed with Hitachi gel 3053. The column was eluted using a gradient elution of increasing acetonitrile concentration, in a mixture of NaCl-HCl at a flow rate of 1.0 ml/min, monitoring the column effluent at 220 nm with an UV detector. Fractions eluted every 1-2 min were collected and lyophilized for subsequent CRF bioassay and radioimmunoassay. When various neuropeptide mixtures including synthetic ovine CRF were injected onto the column, synthetic ovine CRF was separated from the other neuropeptides with a gradient of 0-60% acetonitrile in 0.1 M NaCl-0.01 N HCl or 0-08% acetonitrile in 0.05 M NaCl-0.01 N HCl. The median eminence extracts showed two main peaks of CRF bioactivity on HPLC. One (small CRF) coeluted with arginine vasopressin and oxytocin markers, and the other (big CRF) appeared near the position of synthetic CRF and was divided into two peaks. One coeluted with synthetic ovine CRF and the second eluted after synthetic CRF, showing high CRF activity. Three or four peaks of CRF immunoreactivity appeared on HPLC and the main peak appeared after synthetic ovine CRF marker. Our results suggest that rat CRF is different from ovine CRF, and the total lipophilicity of amino acid residues of rat CRF may be higher than that of ovine CRF.

Animals↗
PubMed1983

Plasma inactive renin in patients with hyperthyroidism.

Active and inactive PRA were measured after 1 h at rest in 16 normal controls and 20 patients with hyperthyroidism. In some of the patients these measurements were repeated after they had become euthyroid or received 90 mg propranolol for 1 week. Inactive PRA was determined as the difference between total PRA after trypsin activation and active PRA. Active PRA was significantly higher (P less than 0.01) in untreated patients than in normal subjects; however, the inactive PRA of patients was not different compared with that of normal subjects. Active PRA was normalized, and inactive PRA did not change after achievement of euthyroidism. The proportion of active of total PRA was significantly correlated with the levels of serum thyroid hormones (T3 and T4) in hyperthyroid patients (r = 0.46; P less than 0.05 and r = 0.55; P less than 0.01, respectively). The administration of propranolol reduced active PRA (P less than 0.05) and increased inactive PRA slightly but not significantly. These results indicate that in hyperthyroidism, the in vivo conversion of inactive renin to active renin is probably facilitated by increased sympathetic activity.

Adult↗
PubMed1983

Prevalence of diabetes mellitus detected by 75 g GTT in Tokyo.

Oral glucose tolerance test (75 g GTT) was performed on 5,172 subjects who received physical checkups at Daiichi Survey Center from April 1981 to March 1982 and the Prevalence of diabetes in Tokyo was studied using the new diagnostic criteria of WHO (1980). The diabetic test was obtained in 3.6% of the subjects over 30 years old. Diabetic retinopathy was found in 4.3% of the diabetic cases. The prevalence of diabetes increased with fasting blood glucose (FBG) and it was considered to be adequate to set the screening point for diabetes mellitus by FBG at 100 mg/dl. 50 g GTT and 75 g were performed in 10,456 cases and 11,925 cases, respectively, and mean 1-hour and 2-hour values were compared by FBG levels. The results show that 2-hour values in 50 g GTT which correspond those of 120 mg/dl and 180 mg/dl in 75 g GTT may be 105 mg/dl and 150 mg/dl, respectively. However it is not reasonable to make the conversion by adding a certain value, because the differences varies markedly with each case.

Adult↗
PubMed1983

Cell-free translation of human renin mRNA.

The molecular weight of human renin precursor (preprorenin) was determined to be 43,000 by cell-free translation of its mRNA. Poly(A)+-containing RNA from human infarcted kidney was translated in a cell-free reticulocyte lysate system containing [35S] methionine. Immunoprecipitation with anti-renin antibody gave one major band with an apparent Mr = 43,000, as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and fluorography. The specific band, which represents the prepro-form of human renal renin, was very similar to mouse submandibular gland preprorenin in its electrophoretic mobility.

Animals↗
PubMed1983

Alveolar soft-part sarcoma. A review on its histogenesis and further studies based on electron microscopy, immunohistochemistry, and biochemistry.

To date, the histogenesis of alveolar soft part sarcoma has been considered to be of paraganglioma origin, striated muscle cell origin, or as a malignant granular cell myoblastoma, neural neoplasm, or renin-producing tumor. Further studies for these existing theories were performed based on various methods. The negative formaldehyde-induced fluorescence and the immunohistochemical absence of neuron-specific enolase were against the paraganglioma theory. The immunohistochemical absence of myelin proteins (P2 protein and PO protein) and S-100 protein were against the malignant granular cell myoblastoma and neural neoplasm theory. Furthermore, there was a totally negative immunohistochemical finding for renin in the tumor cells, and the biochemical relationship of the tumor and renin was completely negated. The contradiction in a well-known report that the components of crystals were considered to be Z-band materials such as tropomyosin was referred to based on recent myological data. Concurrently, the absence of tropomyosin was immunohistochemically demonstrated. Hence, the issues on the histogenesis of alveolar soft part sarcoma and the identity of the characteristic crystalloids remain open for discussion.

Adult↗
PubMed1983

Tractional detachment of the macula following branch retinal vein occlusion.

In two patients, a detachment of the macula occurred following a branch retinal vein occlusion. Vitreoretinal relationships were investigated and documented by biomicroscopic photography. Both eyes showed partial posterior vitreous detachment with dense adhesions to a preretinal membrane at the macula. Vitreous contraction and traction appeared to be responsible for the detachment.

Aged↗
PubMed1983

A new technique in echocardiology: B-mode to M-mode transformation.

In conventional two-dimensional Echocardiography with sector scanning, M-mode is simultaneously displayed on TV-monitor as the time based ultrasound signals. With conventional system, one end of the cursor-line in B-mode image which indicates the beam direction of M-mode, is always fixed at the point corresponding to the transducer tip. This system has the capability to transform B-mode to M-mode images in any desired direction. However, the time resolution in M-mode is limited to about 33 milli-seconds.

Biometry↗
PubMed1983

3-D envisioning by real time perpendicular bi-plane echocardiography (simultaneous multifrequency ultrasonography-III).

Simultaneous dual B-modes, the tomographic plane of which can be moved freely keeping the intersecting angle always perpendicular, was devised and based on simultaneous multifrequency ultrasonography (Miwa, et al, 1981). Dual probes, the ends of which are linked by two arms and three nodes with potentiometers are used to display the intersecting line on the both B-mode images by computation. Both images can be displayed together on one CRT, or separately on the different CRTs. This has proved to be a great help for understanding the 3-D structure of heart. Quantitative dimension and displacement speed measurement of 3-D structure of heart such as myocardium thickness, inner diameter of ventricle, and their changing speed, can be performed very exactly at the accurate three dimensional orientation to the heart. We have also recognized that measuring beam for M-mode must be guided to an exact orientation by this technology. Otherwise, unexpected error has been introduced very usually, if guided only by conventional single B-mode due to lack of information of three dimensional incident angle to the wall, valve,..

Biophysical Phenomena↗