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Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 865 records · Page 48Linked to original sources
PubMed1988

[The suction signal detected by color Doppler echocardiography in patients with mitral regurgitation: its clinical significance].

The present study clarified the clinical significance of the suction signal--regurgitant signal near the mitral valve in the left ventricle--as obtained by two-dimensional color Doppler echocardiography in patients with mitral regurgitation. The study population consisted of 39 patients with various heart diseases having mitral regurgitation. The presence of a mitral regurgitant signal was determined not only in the left atrium but in the left ventricle using the long-axis view, four-chamber view, and short-axis view. 1. The suction signal was observed in 17 cases; on the posteromedial commissure side in four; the central portion in seven; the anterolateral commissure side in five and the mitral aneurysm portion in one. The site of the suction signal indicated the mitral regurgitant orifice and was useful for identifying the regurgitant orifice particularly in cases with prolapse of the commissural scallop. 2. Left ventriculography was performed in 18 cases and the severity of mitral regurgitation was grade III/IV or IV/IV in seven of eight cases with suction signals and was grade II/IV in the remaining one, while it was grade II/IV or I/IV in all ten cases without the signal. Sensitivity was then 100% and specificity was 91% in diagnosing III/IV or greater regurgitation according to the presence of the suction signal. The left atrial jet distance, width and area in the 17 cases with suction signals were significantly greater than those of 22 cases without the signal (3.3 +/- 1.0 vs 1.9 +/- 0.7 cm, 1.4 +/- 0.7 vs 0.8 +/- 0.4 cm, and 4.2 +/- 2.8 vs 1.3 +/- 1.3 cm2, respectively). Thus, the suction signal in the left ventricle in mitral regurgitation provided useful information concerning not only the identification of a regurgitant orifice, but the grade of mitral regurgitation, as well.

Adult↗
PubMed1988

[Left ventricular diastolic reserve during acute pressure loading in hypertrophic cardiomyopathy and dilated cardiomyopathy].

To evaluate left ventricular diastolic reserve during acute pressure loading, changes in mitral flow velocity patterns before and after the elevation of blood pressure were analyzed by pulsed Doppler echocardiography in 11 cases of hypertrophic cardiomyopathy (HCM), nine cases of dilated cardiomyopathy (DCM), and 11 control subjects. Systolic blood pressure was elevated 25% above basal values by methoxamine infusion (0.01 mg/kg/min). Before and after methoxamine, left ventricular dimension and mitral flow velocity pattern were obtained by M-mode and pulsed Doppler echocardiography, respectively. The peak velocity in the rapid filling and atrial contraction phases and time-velocity integrals were measured from the flow pattern. After methoxamine, left ventricular diastolic dimension was significantly increased in all groups, from 43.8 +/- 4.7 mm to 47.4 +/- 4.9 mm in the control subjects, from 43.7 +/- 6.3 mm to 47.2 +/- 6.0 mm in HCM, and from 57.9 +/- 6.4 mm to 60.6 +/- 5.9 mm in DCM. Left ventricular systolic dimension was significantly increased from 48.6 +/- 8.4 mm to 52.8 +/- 8.3 mm in DCM, but not in the control subjects or HCM. The peak velocity in the rapid filling phase was significantly increased from 60 +/- 16 cm/sec to 69 +/- 14 cm/sec in the control subjects and tended to be increased from 44 +/- 13 cm/sec to 52 +/- 12 cm/sec in HCM. The extent of this increase tended to be less in HCM. However, the peak velocity in the rapid filling phase tended to decrease in DCM. There were no consistent trends of changes in the peak velocity in the atrial contraction phase in any groups. The mitral velocity integral increased from 502 Hz-sec to 621 Hz-sec in the controls and from 525 Hz-sec to 613 Hz-sec in HCM, but it did not increase in DCM. These findings suggest that there is impaired diastolic reserve during acute pressure loading in HCM and DCM and that the diastolic disturbance might be reflected in the early diastolic phase, rather than in the late diastolic phase.

Adult↗
PubMed1987

Induction of ocular tumor by nickel subsulfide in the Japanese common newt, Cynops pyrrhogaster.

Chemically induced ocular tumors in amphibians have not been reported previously. In the present study, nickel subsulfide (Ni3S2) was administered to lentectomized Japanese common newts, Cynops pyrrhogaster, by a single injection into the posterior chamber of the right eye (40-100 micrograms Ni3S2/newt). Control newts received a similar injection of vehicle. Malignant melanoma-like tumors developed in the injected eyes of seven of eight Ni3S2-treated newts at 9 months (versus none of six controls). Tumor cells occupied the entire globe and invaded the surrounding tissues. At 11 months melanoma-like cells in treated eyes exhibited by electron microscopy deeply invaginated nuclei and various degrees of pigmentation. Some cells even contained crystalline Ni3S2 in the cytoplasm at 11 months. Mitotic figures were rare in treated eyes at 9 months but were often found in them at 3 months. In one of the seven tumor-bearing eyes at 9 months, a prominent metaplastic cartilage was observed within the globe. A regenerated lens was noted at 9 months in a Ni3S2-treated eye which escaped tumor induction. The site of tumor origin was assumed to be the iris, because the aberrantly proliferating cell population was predominantly found in the root of the iris in treated eyes at 3 months.

Animals↗
PubMed1987

Elution behaviour of peropyrene-type polycyclic aromatic hydrocarbons in liquid chromatography.

The elution behaviour of peropyrene-type polycyclic aromatic hydrocarbons (PAHs) on variously bonded stationary phases in non-aqueous reversed-phase liquid chromatography has been investigated. The results clearly indicate that the retention behaviour is effected by the degree of planarity of the PAHs and by the properties of the stationary phases used. Solute planarity might also be influenced by solvation. Therefore, these factors combine to determine the retention of large PAHs.

Chemical Phenomena↗
PubMed1987

Molecular cloning and sequence analysis of full-length cDNA for mRNA of adrenodoxin oxidoreductase from bovine adrenal cortex.

A full-length cDNA clone (pADR) for adrenodoxin reductase was isolated by means of immunological screening from a bovine adrenal poly(A)+ mRNA library. A cDNA insert of 1,973 base pairs in length encoded the entire amino acid sequence of the adrenodoxin reductase precursor protein, which consists of 492 amino acids including an extrapeptide of 32 amino acids at the NH2-terminus. The cloned cDNA contained the complete 3'-noncoding region of 443 nucleotides including 59 nucleotides of poly(A) and 51 nucleotides in the 5'-noncoding region. The amino acid sequences from the 33rd to 70th, the 117th to 123rd, the 207th to 225th, the 247th to 323rd, the 385th to 426th, the 444th to 461st, and the 487th to 492nd in the predicted structure were identical with those of the purified adrenodoxin reductase and its digested peptides, with only four exceptions.

Adrenal Cortex↗
PubMed1987

Liquid chromatographic retention behaviour in the separation of anti-epileptic drugs on phenyl-, diphenyl-, and triphenyl-bonded silicas and glasses.

The retention and selectivity behaviour of some anti-epileptic drugs were studied by high-performance liquid chromatography on 21 kinds of phenyl-modified porous glasses and silicas, prepared from solutions of phenyldimethylchlorosilane, diphenylmethylchlorosilane or triphenylchlorosilane in xylene, and from various kinds of glass or silica with various mean pore diameters and/or specific surface areas. From elemental analysis data for carbon, the maximum number of bonded phenyl surface groups per gram (mean pore diameter 15 nm, specific surface area 217 m2/g, pore volume 0.85 ml/g) in phenyl-, diphenyl-, and triphenyl-bonded gels was calculated to be 0.313, 0.159, and 0.112 X 10(21), respectively. Using various acetonitrile-0.01 M potassium dihydrogen phosphate mixtures as eluents, the anti-epileptic drugs were separated on all the gels studied, but with different degrees of resolution. With increase in specific surface area on the glasses or silicas, the k' values of three anti-epileptic drugs increased. The selectivity for the separation of carbamazepine and diphenylhydantoin is discussed and explained by the pi-pi interaction between solutes and stationary phases. It has been shown that diphenyl and triphenyl phases are more suitable stationary phases for the selective separation of anti-epileptic drugs than monophenyl phases.

Anticonvulsants↗
PubMed1987

Elution behaviour of planar and non-planar polycyclic aromatic hydrocarbons on various chemically bonded stationary phases in liquid chromatography.

The elution behaviour of planar and non-planar polycyclic aromatic hydrocarbons has been studied on various stationary phases in reversed-phase and normal-phase liquid chromatography. The results show that the elution behaviours of the isomer sets which have distinctly different planarities such as triphenylene, triphenylmethane or o-terphenyl reflect the characteristics of the chemically bonded stationary phases. The phases studied included polymeric C18, monomeric C18 (with end capping), monomeric C18 (without end capping), triphenyl, naphthylethyl and pyrenylethyl phases.

Chemical Phenomena↗
PubMed1987

Elution behaviour of peropyrene-type polycyclic aromatic hydrocarbons in various chemically bonded stationary phases in reversed-phase liquid chromatography.

The elution behaviour of polycyclic aromatic hydrocarbons (PAHs, 13 of the 16 U.S. Environmental Protection Agency priority pollutants and peropyrene types) was studied on several chemically bonded stationary phases (octadecylsilicas, di- and triphenylsilicas, naphthylethylsilica and pyrenylethylsilica) under reversed-phase conditions. The results showed that the elution order of peropyrene-type PAHs is highly dependent on the degree of planarity of the solute and on the orderlines of the bonded phases, whereas no definite differences were found in the retention behaviour of the 13 small PAHs on various stationary phases. The characteristics of all the stationary phases could be classified by statistical cluster analysis.

Chemical Phenomena↗
PubMed1987

Induction of granuloma-dependent angiotensin-converting enzyme and eosinophil chemotactic factor in the skin of athymic nude mice.

Activities of angiotensin-converting enzyme (ACE), other proteinases, and eosinophil chemotactic factor (ECF-G) are known to be elevated in hepatic hypersensitivity granulomas of thymus intact (nu/+) mice after Schistosoma mansoni infection. The enzyme activities also increase, but to a lesser degree in hepatic granulomas of athymic nude (nu/nu) mice, and ECF-G is not detectable. In this study isolated hepatic granulomas from nu/+ mice were grafted into the skin of uninfected nu/nu mice, and changes in those cellular functions were determined to examine whether the newly formed granulomas by recipient nu/nu cells acquire the functional activities as well as the histological appearance of nu/+ granulomas. ACE and ECF-G rapidly disappeared from grafted sites during the first 5 days, corresponding to loss of nu/+ cells from the graft. Reduction in activities of arylsulfatases, lysozyme, and acid phosphatase also occurred, but to a lesser extent. Recovery of ACE and ECF-G activities to the levels seen in nu/+ hepatic granulomas was observed by 14 days after grafting when nu/nu cells had accumulated in the grafts and formed new granulomas. Other enzymes increased to approximately half the levels seen in grafted donor granulomas. Circulating eosinophilia also increased. The findings indicate that nu/nu cells that accumulated in the skin grafts not only morphologically mimicked nu/+ type granulomas but also demonstrated nu/+ levels of cellular function. Analysis of skin granulomas developing in nu/+ mice after grafting of nu/+ hepatic granulomas showed the similar histology and enzymatic changes, whereas the skin sites inoculated with purified schistosome eggs alone caused neither significant histological changes nor elevation of ACE activity.

Acid Phosphatase↗
PubMed1987

Transvenous mitral commissurotomy examined with transesophageal echocardiography.

Transvenous mitral commissurotomy (TMC) was conducted with transesophageal echocardiography (TEE) in two patients with mitral stenosis. It was possible to see clearly not only the intracardiac structures to be examined by TMC, such as the right and left atria, interatrial septum, and mitral valve, but also the instruments used in TMC, such as the catheter, guidewire, and balloon. It was possible to determine the positional relation between the intracardiac structures and instruments. We could observe all procedures other than Brockenbrough's procedure by both TEE and fluoroscopy at the same time. Although safety and reliability cannot be confirmed from just the two present cases, TEE appears to be applicable to TMC.

Aged↗
PubMed1987

The role of intracellular Ca2+ in the degranulation of skinned mast cells.

The intracellular pH of rat peritoneal mast cells was slightly acidic and compound 48/80 induced a decrease in the cytoplasmic pH of these cells. By means of chemical skinning, it was revealed that perfusion with Ca2+ or inositol 1,4,5-trisphosphate (IP3) induced degranulation dose-dependently in mast cells at concentrations higher than 10 microM and 0.1 microM, respectively. Na+ was essential for the release of histamine from mast cells. An assay based on the binding of 45Ca to mast cell fragments revealed that the intracellular Ca store of the mast cell is located in the endoplasmic reticulum. IP3 liberated Ca from the endoplasmic reticulum.

Animals↗
PubMed1987

Declining trends in blood pressure level and the prevalence of hypertension, and changes in related factors in Japan, 1956-1980.

Trends in age-specific and age-adjusted blood pressure and the prevalence of hypertension were obtained from the National Nutrition Survey of Japan, 1956-1980. The national trends in the age-adjusted blood pressure of people (30-69 years old) in Japan during the 1956-1980 period show an increasing pattern reaching a peak around 1964 followed by a decreasing pattern. To explore the possible factors which have contributed to the change in blood pressure levels, we analyzed the relationship between the blood pressure and several possible factors, including the rate of treatment for cardiovascular diseases (CVD) for men and women, annual salt and alcohol consumption per captia and body mass index (MBI) for men and women. Only alcohol consumption was considered in the analysis of men because women in Japan still tend to drink relatively little alcohol. In simple descriptive analyses, the increasing trend in the treatment rates of CVD seemed to be related to the decrease in the blood pressure level and in the prevalence rate of hypertension for both men and women. The impact of treatment rate seemed to overcome the adverse influence of the increasing trends in BMI. Recent decrease in salt consumption may account in part for the later period of the decreasing trends in blood pressure level and the prevalence of hypertension. In multiple regression analysis using these time series data, CVD, BMI and alcohol consumption were significantly related to blood pressure level and the prevalence of hypertension, although salt was not significant in these analyses.

Adult↗