Is there any effect of volcanic eruptions of Mount Sakurajima on human lungs?--histopathological investigation and measurement of intrapulmonary particulate deposits amounts.

In order to investigate effects of volcanic eruptions of Mt. Sakurajima on human lungs, an amount of intrapulmonary particulate deposits (IPD) and histopathological changes were evaluated, using autopsied lungs of deceased residents of Kagoshima (the area affected most by the volcanic eruptions of Mt. Sakurajima, n = 66) in comparison with those of Saitama (n = 73). The amount of IPD was measured by macroscopic image analysis and by alkaline extraction. Correlation was seen in the IPD values obtained by these two methods (Spearman's correlation coefficient: 0.525). The IPD value measured through chemical digestion, which increased with age, was lower in the residents of Kagoshima (17.0 +/- 6.3 mg/g) than in those of Saitama (26.8 +/- 10.6 mg/g). This difference of IPD value between Kagoshima and Saitama residents was also observed in male, female, smoker and nonsmoker subgroups. The incidence of pulmonary emphysema was not different between Kagoshima and Saitama cases. No silicotic nodules were observed in any cases. But, the incidence of bronchial goblet cell hyperplasia and squamous metaplasia in Kagoshima was higher than that in Saitama in male cases and smoker cases. In Kagoshima cases, the incidence of squamous metaplasia was significantly higher in smokers than in nonsmokers. The synergistic influence of volcanic eruptions and cigarette smoking on human airways was suggested.     

Computer simulations of nuclear reactions by protons with incident energies of 250, 300 and 500 MeV in a human body

Computer simulations of nuclear reactions by protons in a human body were carried out at the incident energies of 250, 300 and 500 MeV. About 20% of the incident protons are absorbed by the body with nuclear interactions and the rest of the protons pass through the body at these energies. Radiation of gamma rays from the body and radioactivity of the body were estimated as a function of the time after irradiation with the proton beam.     

Falls among community-dwelling psychogeriatric patients

Although increasing interest has been focused on falling in the elderly, little is known about the incidence and consequence of falls in psychogeriatric outpatients. We conducted a 1-year prospective study of falling in 102 community-dwelling elderly patients with psychiatric morbidity (mean age: 70 years) and 100 mentally intact elderly patients (controls, mean age: 74 years). The subject group comprised 79 patients with depression, 14 with dementia and nine with combined disease based on DSM-III-R criteria. Overall, 216 falls in the subject group and 54 in the controls were reported. At the end of the study, recurrent fallers aged 75 years and older showed significant physical deterioration. Multiple logistic regression analysis of selected medical and demographic variables indicated that the most influential variable regarding falling of the subjects was severity of depression rated using the Hamilton scale. Unexpectedly, the analysis revealed that the use of antidepressants was associated with a lower likelihood of falling. On the basis of the two variables, 75% of all respondents were correctly classified as fallers or non-fallers.     

Relationship between central actions of bradykinin and prostaglandins in the conscious rat

Intraventricular injection of bradykinin produced a dose-dependent increase in the mean arterial blood pressure of conscious rats. With 5 nmol of bradykinin, a dual pressor response was observed, which was associated with a biphasic behavioral change. With repeated hourly injections of bradykinin, tachyphylaxis developed to the pressor and central nervous system (CNS) stimulating effect. Indomethacin, given intraventricularly, reduced the hypertension and the behavioral excitation caused by bradykinin in a dose-dependent manner. When prostaglandin E₂ was injected into the cerebral ventricles, it induced hypertension and behavioral sedation similar to the secondary response to bradykinin. These results suggest that bradykinin has a dual action on the CNS, and this is mediated by prostaglandin-related systems in the brain.     

Detection of immunoregulatory factors in retroplacental serum in human pregnancy

Retroplacental serum (RPS) obtained from pregnant women at term deliveries was studied for regulatory effects on T-lymphocyte proliferation and for pregnancy-associated substances and compared with peripheral serum (PS) of the same donor. Proliferative response to phytohemagglutinin and alloantigens in RPS was lower than that in PS. RPS contained higher levels of human placental lactogen, progesterone, estradiol, and prostaglandin E2 than of PS. However, there were no differences in concentrations of pregnancy-associated alpha 2-glycoprotein, pregnancy-specific beta 1-glycoprotein, prostaglandin F2 alpha, alpha-fetoprotein, human chorionic gonadotropin, cortisol, carcinoembryonic antigen, and immunoglobulins between RPS and PS. The amounts of human placental lactogen, progesterone, or prostaglandin E2 seen in RPS did not inhibit T-cell proliferation. Mixtures of various doses of these three substances were still not inhibitory. Thus, the suppressive activity of RPS could not be explained by these pregnancy-associated substances, but a possible involvement of unknown immunoregulatory factors at fetomaternal interface might be suggested.     

Oxidative metabolism of propylthiouracil by peroxidases from rat bone marrow

1. Propylthiouracil (PTU) was degraded by myeloperoxidase (MPO) or eosinophil peroxidase (EPO), purified from rat bone marrow, in the presence of H2O2 and Cl-. In the absence of either H2O2 or Cl-, MPO and EPO do not degrade PTU. Optimum concentrations of KCl for MPO and EPO were 50 and 250 mM, respectively. 2. The characteristics of PTU degradation by MPO-H2O2-Cl- were similar to those of the chlorinating activity of the peroxidase. 3. Hypochlorous acid as well as MPO-H2O2-Cl- also degraded PTU. Metabolites of PTU degradation by MPO-H2O2-Cl-, which were separated by C18 reversed phase h.p.l.c., were the same as those produced by hypochlorous acid. 4. Of the metabolites of PTU formed by MPO-H2O2-Cl-, one was identified as PTU sulphonic acid (6-propyl-4-hydroxypyrimidine-2-sulphonate) and another seemed to be propyluracil.     

Studies on the mechanism of the cardiotonic activity of MDL 19205: effects on several biochemical systems

MDL 19205, 4-ethyl-1,3-dihydro-5-(4-pyridinyl-carbonyl)-2H-imidazol-2-one, is a new drug with cardiotonic properties. Its effects on several biochemical systems considered to be important in myocardial contraction were investigated. Cyclic nucleotide phosphodiesterases (PDEs) from dog hearts were separated into three isoenzymes, F I, F II, and F III, and effect of the drug on these enzymes was tested. MDL 19205 inhibited F III PDE specifically and produced little or no inhibition of F I and F II PDEs. The IC50 for inhibition of F III PDE was 8.6 microM when 0.5 microM cyclic AMP (cAMP) was used, whereas no more than 10% inhibition of F I and 18% of F II PDEs occurred at drug concentrations up to 200 microM when 1 microM cAMP was used. Concentrations of MDL 19205 up to 100 microM had no effect on Ca2+-adenosine triphosphatase (ATPase) or Ca2+ uptake by dog cardiac sarcoplasmic reticulum. At 100 microM, the drug produced a weak (18%) inhibition of Na+,K+-ATPase. It is suggested that inhibition of F III PDE may be the primary mechanism by which MDL 19205 produces its cardiotonic effect. Inhibition of Na+,K+-ATPase may also be involved at very high concentrations of this drug.     

Anion channels contribute to the regulation of intracellular pH in human platelets

The presence of extracellular bicarbonate potentiated platelet intracellular pH rises induced by thrombin. The effect was most remarkable in sodium-depleted buffers. This effect of bicarbonate was dose-dependent and was inhibited by anion channel blockers. Bicarbonate also potentiated the pHi recovery after acid loading, but had no effect on alkali loading. It was suggested that anion exchange, most probably that of bicarbonate/chloride, contributes to the regulation of intracellular pH in human platelets.