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Biomedical subjects

T Ashida

Publications and source records attributed to T Ashida.

At least 163 records · Page 9Linked to original sources
PubMed1983

Circadian rhythm of blood pressure in primary aldosteronism and renovascular hypertension--analysis by the cosinor method.

The circadian rhythm of blood pressure in 11 patients with primary aldosteronism (ALD) and 15 patients with unilateral renovascular hypertension (RVH) was analyzed using the cosinor method which fits a cosine function to a series of data. In ALD, both systolic (SP) and diastolic blood pressures (DP) increased in the late evening; the amplitude and acrophase of the circadian rhythm for SP were 7.3 (5.3 to 9.3, mean and 95% confidence limits) mmHg and 20:47 (19:42 to 21:52) hours, respectively, and for DP 2.6 (1.3 to 3.9) mmHg and 21:34 (19:40 to 23:28) hours, respectively. After excision of an adrenal adenoma in 6 patients, the circadian rhythm of SP and DP was abolished. In RVH, the acrophase of the circadian rhythm of SP and DP differed by about 12 hours; the amplitude and acrophase for SP were 5.7 (3.9 to 7.5) mmHg and 17:49 (16:35 to 19:02) hours, respectively, and for DP 1.5 (0.2 to 2.7) mmHg and 6:08 (2:44 to 9:31) hours, respectively. After various surgical interventions in 8 patients, the circadian rhythm of SP persisted with little change in acrophase, while that of DP disappeared. The difference in circadian rhythm suggests a difference in mechanisms of blood pressure control in ALD and RVH.

Adenoma↗
PubMed1982

An extensive primary myocardial fibrosis in progressive systemic sclerosis--a case report with autopsy findings.

An extensive myocardial fibrosis due to progressive systemic sclerosis (PSS) was described in a 36-year-old normotensive woman without pulmonary hypertension. An electrocardiogram showed low voltage and a pseudo-infarctional pattern in leads V1 through V3. Right ventricular dilatation and generalized left ventricular hypokinesis were present, but her pulmonary artery pressure was normal. Serum creatine kinase (CK) was elevated to 2305 U/L and CK-MB isoenzyme was as high as 7.1%. Simultaneously performed isoenzyme analysis of CK from the homogenate of the skeletal muscle of the patient showed a similar pattern, thus confirming that serum CK originated mainly from the skeletal muscle lesions. Autopsy findings demonstrated diffuse myocardial fibrosis and relatively unremarkable changes in the lungs and the kidneys. Our case serves as a warning that primary myocardial fibrosis could be, in some cases, so extensive that it might lead to a rapidly aggravated myocardial dysfunction and eventual death.

Adult↗
PubMed1982

Effects of dietary sodium on brain angiotensin II receptors in spontaneously hypertensive rats.

The effects of dietary sodium on the characteristics of angiotensin II (A II) receptor sites in the hypothalamus-thalamus-septum-midbrain (HTSM) region were examined in spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Twenty-four SHR and 24 WKY were divided into two groups respectively, which were maintained on high sodium diets or low sodium diets for 4 weeks, respectively. The binding capacity and affinity of the A II receptors were measured by radioreceptor assay. In WKY, the binding capacity of the A II receptors in the high sodium group was significantly lower than that in the low sodium group. On the other hand, the binding capacity of A II receptors in the high sodium group was significantly lower than that in the low sodium group. On the other hand, the binding capacity of A II receptors was not significantly different between high and low sodium groups in SHR. The secretion of arginine vasopressin (AVP) increased significantly in SHR with high sodium intake. The present results suggest that in WKY the decrease of the binding capacity of the A II receptors in the HTSM region in response to a high sodium intake serves to attenuate an osmotical stimulus to AVP secretion. However, in SHR such a regulatory mechanism as adjusting the binding capacity of the A II receptors is lacking, and this seems to be responsible, at least in part, for the enhanced secretion of AVP on the sodium loading.

Angiotensin II↗
PubMed1981

Beta-pleated sheets in oligopeptide crystals.

Many oligopeptide crystals show the beta-pleated sheet structures. Both parallel and antiparallel chain pleated sheets are found, and also both ideal (flat) and heavily twisted sheets are found. The structural parameters, such as the T (NC alpha C') angles, the torsion angles (phi and psi), the fiber axis periods, the hydrogen bond lengths, and the interchain spacings, are studied. Some of them deviate significantly from those proposed by Pauling & Corey ()Proc. Natl. Acad. Sci. US (1953), 39, 253-256). In the heavily twisted sheets, the twists are large than those in the globular proteins, and each two neighboring chains are almost perpendicular with each other, preserving the beta-sheet type hydrogen bond system. The torsion angles in the twisted sheets are rather close to those of the poly (L-proline) II helix. It also is discussed that the T (NA alpha C') angles sometimes deviate by almost 5 degrees from the standard value depending on the structures of the main and side chains.

Crystallization↗
PubMed1981

The importance of vasopressin in the mechanism maintaining hypertension in the rat.

The further role of vasopressin in the pathogenesis of hypertension was studied in two different types of hypertensive rats in which the intravenous injection of a vasopressin antiserum reduced arterial blood pressure substantially. The increased secretion of vasopressin was demonstrated in deoxycorticosterone acetate (DOCA)-salt hypertensive and spontaneously hypertensive rats with high salt intake. Angiotensin II binding of the brain receptor which has been postulated to modify osmotically stimulated vasopressin release from neurohypophysis was not affected by sodium balance in these types of hypertensive rats, whereas the decrease in the brain receptor binding of angiotensin II was observed in the control rats. The lack of the adjusting control system in the brain angiotensin II receptors for sodium balance may be, at least in a part, responsible for the enhancement of vasopressin secretion in the hypertensive rats compared to that in the control rats with high salt intake. Since pressor responsiveness to vasopressin was increased in the rats with DOCA-salt hypertension, vasopressin may function as a direct pressor agent in the maintenance of high blood pressure in this type of hypertension.

Angiotensin II↗
PubMed1975

The crystal structure of bonito (katsuo) ferrocytochrome c at 2.3 A resolution. II. Structure and function.

The structure analysis of bonito heart ferrocytochrome c was carried out at 2.3 A resolution by X-ray diffraction, and a Kendrew-type skeletal model was built up. This molecule has an overall egg shape, 35 A in height, 30 A in width and 23 A in thickness; the 5th ligand of the heme iron atom is the N-epsilon atom of the His-18 imidazole ring and the 6th is the Met-80 sulfur atom. Distinct alpha-helix regions are found between the N-terminus and reside 11, between 60 and 69, and between 90 and the C-terminus. The most distinct difference between the conformation of the present molecule and that of the horse oxidized molecule is the location of the Phe-82 phenyl ring. In the present reduced molecule, the phyenyl ring is in closer contact with the iron atom and gives influences on the character of the iron atom. Inside the molecule, at the lower part of the heme pocket, there is an extended hydrogen bond network including the propionic acid residues of the heme group. Both Phe-82 and the hydrogen bond network may play a key role in the function of this molecule.

Amino Acid Sequence↗