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Biomedical subjects

H Maezawa

Publications and source records attributed to H Maezawa.

At least 109 records · Page 6Linked to original sources
PubMed1984

The hemodynamics and hemodynamic effects of indenolol in mild hypertension.

For clarifying the onset mechanism of essential hypertension, the hemodynamics in 9 mildly hypertensive men, mean age of 39.8 +/- 10.7 (mean +/- SD), was compared with 7 normotensive men, mean age of 39.8 +/- 10.7, by means of exercise echocardiography, and the effects of indenolol (administered 30 mg/day for 7 days orally to both groups) were studied. The interventricular septum and the left ventricular posterior wall were thickened in the mild hypertensives. No significant differences between the both groups were shown in the cardiac performance at rest and the cardiac index during exercise. The total peripheral vascular resistance was higher in the mild hypertensives than the normotensives during exercise. However, during exercise, the normotensives showed significant increases in the left ventricular end-diastolic dimension (LVDd) and the stroke index (SI); these changes were not significant in the mild hypertensives. After administration of indenolol, the significant increases in LVDd and SI during exercise were observed in the mild hypertensives. This study suggests that mild hypertensives with cardiac hypertrophy display a diminished Frank-Starling effect during exercise which may be attributed to the decreased left ventricular compliance due to cardiac hypertrophy and elevated afterload. Indenolol improved the Frank-Starling effect, which decreased in the mild hypertensives.

Adult↗
PubMed1984

Total body irradiation as a method of preparation for bone marrow transplantation: a new technique and review.

Recently total body irradiation has been used as a method of preparation for the bone marrow transplantation. However, it has become apparent that total body irradiation is one of the causes of interstitial pneumonia. There are several factors in total body irradiation that may induce interstitial pneumonia. 1) Total dose. Usually 10 Gy which is used in America, reduces the survival of the leukemic cells to about 0.001% while the normal tissue cells are reduced to about 1%. However there is no evidence that 10 Gy is enough for bone marrow transplantation. 2) Dose rate. A dose of 10 Gy given at a high dose rate is about 10 times more effective than at a low dose rate. However, the dose-rate effects become less pronounced when the single dose is under 2 Gy. 3) Dose fractionation. The effect on cell survival of dose fractionation is discussed. Since the recovery from the radiation damage is usually greater in normal cells than in the malignant cells, fractionated radiation will have great advantages. 4) Dose distribution and new irradiation technique. It is difficult to obtain homogeneous distribution if a single large radiation field is used. In our hospital the patients receive total body irradiation by a moving treatment couch method under X-rays exposure. Homogeneous dose distribution is achieved with this method. Total body irradiation will become an almost routine treatment method for bone marrow transplantation with multifractionated irradiation.

Bone Marrow Transplantation↗
PubMed1984

High density lipoprotein and diabetes mellitus.

The serum HDL2-C, HDL3-C, apo AI and apo AII levels were measured in the non-insulin-dependent diabetic subjects (NIDD) and normal subjects to study the metabolism of HDL in the diabetics. The serum HDL2-C levels in the insulin-treated group were significantly higher than those in the normal group in which the total cholesterol (TC), triglyceride (TG), obesity index and age were matched whereas there was no difference between the serum HDL2-C levels in the oral agent-treated group or group treated by diet only and those in the normal group. These suggest that insulin increases the HDL2-C levels and the increase of the HDL2-C levels is not directly related to changes in the serum TC and TG levels, obesity index and age. No significant differences in the serum apo AI and apo AII levels were found between the insulin group and normal group. From these results it is suggested that in the insulin group the cholesterol/apoprotein ratio in the HDL2 is higher than that in the normal group. The serum apo AI and apo AII levels were significantly lower in the diabetics with an ischemic heart disease (IHD) than those in the diabetics without the IHD. The results show that in the diabetics the apo AI and apo AII play an important role in preventing the development of IHD.

Adult↗
PubMed1984

The effect of hypoxic radiosensitizer after mild hyperthermia in C3H mammary carcinoma.

The radiosensitizing effect of misonidazole after hyperthermia was investigated in C3H mammary carcinoma. The tumors transplanted into the flanks of the mice were heated in a 42.3 degrees C water bath for 30 min. When misonidazole was administrated before heating, the subsequent radiation effect was prominently enhanced, whereas post-heating administration of misonidazole did not enhance the radiation effect significantly. The effect of varying the time between heating and radiation with or without misonidazole was as follows. Without misonidazole, the radiation effect was decreased at 6 hours after heating but increased at 12 hours, then it returned to the initial level at 24 hours and remained until 96 hours after heating. With misonidazole administered 30 min before irradiation, the radiosensitizing effect was observed at 24, 48 and 96 hours after heating. However, the total effects of this procedure were almost the same as the results in the combination without heating. Changes in the hypoxic fraction after hyperthermia are also discussed.

Anaerobiosis↗
PubMed1984

Polarographic measurement of misonidazole in mouse mammary tumors.

The sensitizing effect of misonidazole, a hypoxic cell radiosensitizer, is presumed to be due to its strong electron affinity. The concentration of misonidazole in mouse mammary tumors was measured polarographically in vivo. When 1 mg of misonidazole per gram body weight was administered intraperitoneally to C3H/He mice, 0.5-0.75 mM of misonidazole was observed in the tumors 25-60 min later. The distribution of misonidazole in the tumors varied, but the mean concentrations were not significantly different except in the necrotic area and the central-superficial region, where the concentration of misonidazole tended to be lower than in the other regions. No differences in the concentration of misonidazole were observed in tumors with diameters ranging from 4 to 11 mm. The polarographic measurement of misonidazole in vivo is technically simple and can be applied to the study of hypoxic cells in tumor tissue.

Animals↗
PubMed1984

Synchrotron system for monochromatic uv irradiation (greater than 140 nm) of biological material.

An irradiation system of monochromatic uv radiation down to the wavelength of 140 nm was constructed for biological irradiation experiments in the vacuum-uv range using synchrotron radiation (SR) from the electron storage ring. The system consists of premirror chamber, vacuum-uv monochromator, irradiation chamber, and vacuum systems. Along with the detailed description of all components of the system, the installation at the storage ring and the performance characteristics are presented.

Particle Accelerators↗
PubMed1984

Action spectra for inactivation of dry phage T1 after monochromatic (150-254 nm) synchrotron irradiation in the presence and absence of photoreactivation and dark repair.

Dry phage T1 was irradiated with monochromatic uv radiation (150-254 nm) in vacuo. The inactivation sensitivity was highest at 150 nm. On Escherichia coli Bs-1, the phage inactivation sensitivity was two and four times higher at 150 nm than at 254 and 230 nm, respectively. Action spectra for phage inactivation on both E. coli B and Bs-1 fit the absorption spectrum of phage DNA, except around 190 nm. The host-cell- reactivable fraction for vacuum-uv radiation (below 190 nm) was smaller than that with far-uv radiation. There was almost no photoreactivation at 150 nm, in contrast to a photoreactivation sector of about 0.3 at 254 nm.

DNA Repair↗
PubMed1983

Comparison of gliclazide and glibenclamide treatment in non-insulin-dependent diabetes.

Gliclazide has been reported to decrease platelet function and to inhibit the progression of diabetic retinopathy in addition to having a hypoglycemic effect. To confirm these effects we performed a double-blind randomized study using glibenclamide as a reference drug. Thirty-eight hospitals from eight university groups in Japan performed the study on type II diabetic subjects. Evaluation of blood glucose control, platelet adhesiveness, platelet aggregation and blood lipids over 24 weeks were assessed by the central committee. Two hundred and eighty-nine patients were enrolled in the study. Twelve were excluded and 277 were statistically analysed. Homogeneity between the two diabetic groups was demonstrated for background factors. Forty mg of gliclazide was comparable to 2.5 mg of glibenclamide in the potency of hypoglycemic efficacy. Funduscopic aggravations were observed in a statistically smaller number of cases in the gliclazide group than in the glibenclamide group and in evaluation of serum lipids, the gliclazide group was also superior to the glibenclamide group. No significant difference between the two groups was found in platelet adhesiveness and aggregation. Gliclazide is a useful drug in the therapy of diabetes mellitus.

Adult↗
PubMed1982

Hereditary factors in Takayasu's disease.

In an attempt to provide support for the genetic link theory as related to the etiology of Takayasu's disease, we analyzed simultaneously A, B, and D loci of HLA antigens in 75 Japanese patients with the disease. Serving as control were 128 healthy Japanese. A statistically significant high frequency of BW52 and DHO was confirmed with the levels being 25.6 and 10.4, respectively, in the chi 2 test. A haplotype of A9-BW52-DHO was frequently evident in these patients as compared to the controls, and here also the statistical difference was significant. There appears to be a closer relationship of the gene to BW52 than to DHO. A survey of the homozygote of BW52 revealed 6 of 75 patients with BW52; however, statistically speaking, this rate did not differ from the expected one. Thus, our analysis of HLA illustrates the genetic factors involved in Takayasu's disease. The genes are located between the B and D loci and are closer to BW52 than DHO and these genes have a dominant character.

Aortic Arch Syndromes↗
PubMed1982

Changes in the plasma levels of thromboxane B2 and cyclic nucleotides in patients with Takayasu disease.

Plasma thromboxane B2 (TXB2), cyclic AMP and cyclic GMP levels in 31 women with Takayasu disease were measured and findings were compared with data on 34 age-matched healthy Japanese. Platelet aggregation determined by the screen filtration pressure (SEP) method and pulmonary lesions assessed by scintillation were studied in 21 patients. Plasma TXB2 levels in patients with Takayasu disease were 265.8 +/- 20.4 pg/ml, which were statistically higher than the levels of 196.3 +/- 10.7 in healthy controls. On the contrary, cyclic AMP levels in the patients were 9.6 +/- 0.7 pmols/ml, statistically lower levels than 13.5 +/- 1.0 seen in the healthy controls. A positive correlation among cyclic AMP, cyclic GMP and TXB2 levels was confirmed only in the controls. SEP values in the patients with pulmonary lesions were significantly higher than in those without lesions and also in the controls. A positive correlation was obtained between SEP and TXB2 levels in healthy controls, but not in the patients. Thus, thromboxane A2 may play an important role in the pathology of Takayasu disease.

Adult↗
PubMed1982

Inhibitory effect of hydroquinone and related agents on multiplicity reactivation and genetic recombination of bacteriophage T4.

The multiplicity reactivation of T4D phage irradiated with UV was inhibited by treatment of infected cells with 0.5 mM hydroquinone (HQ). HQ also inhibited genetic recombination of T4B rII mutants. The recombination frequency was reduced by treatment of infected cells with HQ in a buffer when compared with an untreated control. In addition to HQ, the effects of quinone, an oxide form of HQ, mercaptoethanol and alpha-tocopherol, antioxidants, were also investigated. Quinone and mercaptoethanol inhibited recombinations but alpha-tocopherol did not.

Escherichia coli↗