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Biomedical subjects

H Tagawa

Publications and source records attributed to H Tagawa.

At least 91 records · Page 5Linked to original sources
PubMed1989

Dosage regimen of ranitidine in patients with renal impairment.

The validity of the Giusti-Hayton method for dosage regimen adjustment in patients with renal impairment was investigated using ranitidine. Five normal healthy volunteers received a single ranitidine recommended dose of 150 mg, and 20 patients with renal disease received single administration in doses individually calculated by the Giusti-Hayton method from each patient's creatinine clearance level, and the various pharmacokinetic parameters were compared. As a result, the area under the time-concentration curve 0----infinity (AUC0----infinity) in the renal disease patients was almost comparable to that in the normal healthy volunteers. The Giusti-Hayton method was considered useful to keep both the AUC0----infinity constant and the mean blood level of the drug in a steady state, in any degree of renal impairment.

Administration, Oral↗
PubMed1988

Temperature dependence of the structure of aggregates of tobacco mosaic virus protein at pH 7.2. Static synchrotron small-angle X-ray scattering.

The small-angle X-ray scattering (SAXS) method using a synchrotron radiation source was applied to the study of the self-aggregation process of tobacco mosaic virus protein (TMVP) at a concentration of 5.0 or 12.0 mg ml-1 in 50 mM or 100 mM-phosphate buffer (ionic strengths approx. 0.1 and 0.2, respectively) at pH 7.2 in the temperature region of 4.8 to 25.0 degrees C. This paper presents the results of static measurements of SAXS. Sedimentation velocity experiments were performed simultaneously under the same conditions. These results are qualitatively parallel to those of the SAXS measurements, although the size of stacked disks derived from the SAXS measurements is larger than that derived from the sedimentation experiments, suggesting a change in the equilibrium conditions in the centrifugal field. Qualitative analysis of the SAXS data with model simulation calculations implies that the aggregation of TMVP consists of two steps: (1) the aggregation of A-protein comprising a few subunits to form double-layered disks; and (2) the random polymerization of double-layered disks by disk-stacking. Increase in temperature, ionic strength or protein concentration induced TMVP to polymerize to form a double-layered disk or a quadruple-layered short rod with consumption of A-proteins, accompanied by a small number of multi-layered short rods. The SAXS results indicate that the A-protein and the multilayered short rods are polydisperse with respect to size and shape, i.e. the mixture of A-protein, double-layered disks and multi-layered short rods coexists in the equilibrium state without pressure-induced partial dissociation of TMPV as observed during normal ultracentrifugation, and even under solution conditions in which the formation of double-layered disks or higher-order aggregates is favored.

Capsid Proteins↗
PubMed1988

Extrarenal role of aldosterone in the regulation of blood pressure.

To assess the hypothesis that aldosterone may have direct vasoconstrictive action, the acute effects of canrenoate potassium (Soldactone, S), an aldosterone antagonist, on hemodynamics and hormonal responses were determined before and after the intravenous administration of 2 mg/kg S in 11 patients with primary aldosteronism (PA), 9 patients with essential hypertension (EH), and 5 patients with renovascular hypertension (RVH). S caused a significant -12 +/- 2 mm Hg decrease in MBP in PA, -5 +/- 2 mm Hg in EH, and -4 +/- 1 mm Hg in RVH. Reduction in MBP was significantly higher in PA than in the others and there was a negative correlation between changes in MBP and basal PAC. The cardiac index did not change throughout the study in all groups, which led to a significant reduction in total peripheral resistance index (TPRI) in PA but not in the others. There was a significant correlation between changes in MBP and TPRI (r = 0.82, p less than 0.01). PRA did not change throughout the study, but PAC and cortisol were significantly elevated. There were no correlations between changes in MBP and hormonal responses. In conclusion, S resulted in a significant reduction of MBP mediated by a significant reduction of TPRI. These results suggest that aldosterone may have direct vasoconstrictive action and this extrarenal effect of aldosterone may be involved in the regulation of blood pressure.

Adult↗
PubMed1988

Hormonal and renal effects of atrial natriuretic peptide in patients with secondary hypertension.

To investigate the involvement of atrial natriuretic peptide (ANP) in secondary hypertension, we examined hormonal and renal responses to ANP infusion (0.025 microgram/kg/min) in 27 patients with renal parenchymal hypertension, 10 with primary aldosteronism, 8 with renovascular hypertension, and 15 normotensive subjects. The preinfusion plasma concentration of ANP was significantly higher in patients with renal parenchymal hypertension (120 pg/ml, p less than 0.01) and in patients with primary aldosteronism (98 pg/ml, p less than 0.05) than in the normotensive subjects (40 pg/ml), but it was not greater than in the patients with renovascular hypertension (73 pg/ml, NS). In the patients with renal parenchymal hypertension, plasma ANP correlated negatively with creatinine clearance (r = -0.76, p less than 0.001). Mean blood pressure (-5%, p less than 0.01) and plasma aldosterone (-40%, p less than 0.001) decreased to a similar degree in the four groups during ANP infusion. However, an increase in urinary sodium excretion caused by ANP was higher in the hypertensive than in the normotensive patients (+250% vs. +70%, p less than 0.01) and correlated positively with mean blood pressure during ANP infusion (r = 0.47, p less than 0.001). The removal of adenomas in the patients with primary aldosteronism significantly lowered both plasma levels of ANP and cyclic guanosine 2',3'-monophosphate and reduced an increase in sodium excretion during ANP infusion, whereas the responses of blood pressure and plasma aldosterone to ANP infusion were not altered by the operation. Thus, these results suggest that elevated ANP secretion and increased natriuretic responses to ANP may modify the blood pressure and body fluid volume status in some types of secondary hypertension.

Adrenal Gland Neoplasms↗
PubMed1988

Semisynthetic beta-lactam antibiotics. IV. Synthesis and antibacterial activity of 7 beta-[2-(hetero aromatic methoxyimino)-2-(2-aminothiazol-4-yl)acetamido]cephalosporins.

A series of 7 beta-[2-(hetero aromatic methoxyimino)-2-(2-aminothiazol-4-yl)acetamido]- cephalosporins have been synthesized and bacteriologically evaluated. Several substances in this series showed exceptional in vitro activity, especially those with a five-membered hetero aromatic substituent moiety at the 7-position and a quaternary ammonium group as the 3-function of the cephem nucleus. The most active derivative, 7 beta-[2-(imidazol-4-ylmethoxyimino)-2-(2-aminothiazol-4-yl)a cetamido]-3-(pyridiniomethyl)ceph-3-em-4-carboxylate (13a) was the most evenly balanced with respect to activity against Gram-positive and Gram-negative bacteria. Furthermore, 13 was stable to various types of beta-lactamases and had high affinities for penicillin binding protein-3 and -1Bs of both Escherichia coli and Pseudomonas aeruginosa.

Bacteria↗
PubMed1987

Fetal ascites. A report of 3 autopsy cases.

Three rare autopsy cases of fetal ascites were presented and the etiology of each case was described. Case 1 was a male neonate, delivered by cesarean section at 32 weeks' gestation, and died of respiratory failure. The abdomen was remarkably distended with 1020 ml of ascites. The etiology of Case 1 remained unknown even after macroscopic and microscopic examinations. We considered this as "idiopathic" fetal ascites. Case 2 was a female neonate, delivered at 31 weeks' gestation, with marked abdominal distension and cyanosis. Autopsy revealed 435 ml of ascites, and she was considered to have had "polysplenia syndrome" with cardiovascular malformations. Intrauterine heart failure due to cardiac anomalies was thought to be the cause of this ascites. In case 3 embryotomy was carried out under the diagnosis of fetal ascites by ultrasound examination at 22 weeks' gestation. An urachal cyst connected to the dilated urinary bladder and deficiency of musculature of the abdominal wall composed of loose connective tissue with calcification were observed. The abdominal wall was ruptured and 1,960 ml of ascites was measured. Polycystic kidney with renal dysplasia was also found. Case 3 showed "Prune-Berry syndrome" and fetal ascites may have arisen from these anomalies.

Abortion, Induced↗
PubMed1987

Synthesis and antimicrobial activity of cephalosporins with a 1-pyridinium substituent carrying a 5-membered heterocycle at the C-3 position.

A series of potent antimicrobial agents have been prepared. These derivatives are cephalosporins carrying a pyridine ring substituted with a heterocycle in the C-3 position. Some of them showed excellent activity not only against Gram-negative organisms including Pseudomonas aeruginosa but also against Gram-positive ones. In view of their biological and physico-chemical properties, 7 beta-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-[4-(2 or 5-oxazolyl)-1-pyridinium]methyl-3-cephem-4-carboxylate 8f (DQ-2522) and 8g (DQ-2556) were chosen as candidates for further evaluation.

Cephalosporins↗
PubMed1987

Asteroid hyalosis: posterior vitreous detachment and diabetic retinopathy.

The vitreoretinal relationship in 59 eyes with asteroid bodies was studied by biomicroscopy with the El Bayadi-Kajiura lens. Complete posterior vitreous detachment (PVD) occurred less often in eyes with asteroid bodies than in control eyes (P less than .05), and partial PVD occurred more often than in control eyes (P less than .01). In eyes with asteroid bodies after the age of 70 years, the prevalence of PVD, either complete or partial, was lower than in age-matched control eyes (P less than .01), and the prevalence of liquefaction (19%) was lower than has been reported in controls. Of eight eyes with proliferative diabetic retinopathy and asteroid bodies, only one showed partial PVD. Patients who were diabetic and who had asteroid bodies were significantly younger than patients without diabetes with asteroid hyalosis (P less than .01). Our data suggest that the presence of asteroid bodies may arrest the process of vitreous collapse or contraction and that diabetes might influence the development of asteroid hyalosis.

Adult↗
PubMed1987

[Influence of pregnancy on HB virus carriers].

Liver function tests (GOT, GPT) were performed on 269 female HB virus carriers during pregnancy and puerperium with the following results: Pregnancy in HB virus carriers did not result in any deterioration in liver function, but was rather associated with its gradual normalization particularly in symptomatic carriers. At 1 month of puerperium, in contrast, the occurrence or rebound flare-up of hepatitis was frequently observed among the virus carriers, notably with overt liver dysfunction being seen in 43% of those positive for e antigen. Of 28 e antigen-positive carriers in whom a follow-up study was extended to the next pregnancy, 12 whose liver function was normal during puerperium had normal liver function during the next pregnancy and was positive for e antigen. In the other 16 carriers showing deteriorated liver function during puerperium, liver function during the next pregnancy was abnormal in 6 and normal in 10, with seroconversion and negativity for e antigen being observed in 2 and 4, respectively, of these 16. It is inferred that fluctuations in liver function and e antigen during pregnancy and puerperium might be consequent on increased secretion of corticoids during pregnancy.

Carrier State↗
PubMed1986

Role of the vitreous in diabetic retinopathy. II. Active and inactive vitreous changes.

The course of the vitreoretinal relationship in 272 eyes with diabetic retinopathy was studied retrospectively in an attempt to identify the prognostic role of the vitreous. In eyes with initial nonproliferative diabetic retinopathy, the development of neovascularization had a positive correlation with eventual partial posterior vitreous detachment (PVD) and a negative correlation with complete PVD. In eyes with initial proliferative diabetic retinopathy, those with active vitreous changes had a poor prognosis and those with inactive vitreous changes, an apparently good prognosis. Photocoagulation for retinal neovascularization was successful in most eyes with stable no-PVD but less successful in eyes that progressed to partial PVD. Therefore, considering the diabetic vitreous changes from a prognostic standpoint, the data suggest that if early proliferative changes are observed, photocoagulation before partial PVD develops might be considered.

Age Factors↗
PubMed1986

Anterior optic nerve blood flow decreases in clinical neurogenic optic atrophy.

Anterior optic nerve blood flow was studied in nine patients with unilateral neurogenic optic atrophy using noninvasive techniques. Disk reflectometry measurements from temporal sites demonstrated a significant reduction in the index of blood volume in atrophic optic nerves as compared with the contralateral optic nerves (P less than 0.00001). Laser Doppler measurements from the same temporal sites detected a significant reduction in the speed of blood (P less than 0.002). On average, blood volume was decreased by 49% +/- 11% and blood speed by 30% +/- 17%. Combining the results of these two techniques yielded a relative index of blood flow that showed a significant reduction in the atrophic nerves (P less than 0.0001), averaging 64% +/- 14% temporally. Nasally there was less reduction in blood flow. The results correlated well with clinical assessment of the degree of optic nerve damage (rho = 0.92, P less than 0.002). This study demonstrates that clinical neurogenic optic atrophy induces significant reductions in overall anterior optic nerve blood flow that are detected by these noninvasive techniques.

Adolescent↗
PubMed1986

Role of the vitreous in diabetic retinopathy. I. Vitreous changes in diabetic retinopathy and in physiologic aging.

The vitreoretinal relationships in 1021 eyes of 570 patients with diabetic retinopathy and in 857 normal eyes were studied retrospectively in an attempt to identify the vitreous changes specifically related to diabetes. Complete posterior vitreous detachment (PVD) occurred in diabetic patients largely as part of the aging process, but proliferation interfered with its development. Complete PVD with nonproliferative diabetic retinopathy in the younger age groups was more prevalent in eyes treated by panretinal photocoagulation (PRP) than in untreated eyes and thus might have an association with PRP treatment. Partial PVD, seen mainly in proliferative diabetic retinopathy, had no correlation with aging. In the eyes of patients who were younger when diabetes was diagnosed, the development of partial PVD had a close correlation with the duration of diabetes. The data suggest the need for a clinical trial of early photocoagulation, before partial PVD develops, in younger-onset diabetic patients showing early proliferative changes.

Adolescent↗