Pressure dependence of pyrene excimer fluorescence in human erythrocyte membranes

The intensity of pyrene excimer fluorescence in human erythrocyte membranes and in sonicated dispersions of the membrane lipid (liposomes) was examined as a function of pressure (1-2080 bar) and temperature (5-40 degrees C). Higher pressure or lower temperature decreased the excimer/monomer intensity ratios. A thermotropic transition was detected in both membranes and liposomes by plots of the logarithm of the excimer/monomer intensity ratio versus 1/K. The transition temperature of the membranes was 19-21 degrees C at 1 bar and 28-31 degrees C at 450 bar, a shift with pressure of approx. 20-22 K per kbar. Corresponding transition temperatures of the liposomes were 21 degrees C at 1 bar and 33 degrees C at 450 bar, a shift of approx. 27 K per kbar. The observed pressure dependence of the thermotropic transition temperature is similar to that reported for phospholipid bilayers and greatly exceeds that of protein conformation changes. In concert with the liposome studies the results provide direct evidence for a lipid transition in the erythrocyte membrane.

A continuous and quantitative analysis of the uneven distribution of myocardial blood flow in dogs using a distribution function of the clearance time constant

A continuous and quantitative analysis of the uneven distribution of coronary blood flow was accomplished in anesthetized open-chest dogs using the distribution function of the hydrogen (H2) clearance time constant. The distribution function was derived by analysing the H2 washout curves in the coronary sinus which were obtained by the H2 clearance method, using platinum electrodes placed in the coronary sinus. Twelve to seventeen platinum electrodes were employed to obtain simultaneous measurements of the regional myocardial flow before and after stenosis of the left anterior descending coronary artery. Theoretically, the H2 washout curves in the coronary sinus could be interpreted as a function with multi-exponential characteristics, represented by an equation similar to the Laplace transform of the distribution function of the H2 clearance time constant. Therefore, we assumed that such an equation would represent the uneven distribution of coronary blood. We obtained the distribution function by using an approximation method to solve the integral equation and we employed digital computation to increase the resolution. Before stenosis of the left anterior descending coronary artery, the log distribution function curves with respect to the H2 clearance time constant were roughly symmetrical in terms of the maximum peak in the time constant. After stenosis of the left anterior descending coronary artery, the log distribution function had two peaks and the range of distribution was much larger than that before coronary stenosis. Our findings may prove to be valuable as a technique to estimate continuously and quantitatively the heterogeneous distribution of myocardial blood flow.

Periodic urine cytology surveillance of bladder tumor incidence in dyestuff workers

The validity of urine cytology surveillance of occupational bladder tumor incidence was evaluated by reviewing the clinical history of nine bladder tumor cases found in dyestuff plant workers. A bladder tumor surveillance system has been organized for workers (179) active and 65 retired) who had been exposed to benzidine or beta-naphthylamine in the plant. The system consists of two-stage tests: periodic urine cytology as the first-stage screening test, followed by, in suspicious cases, urological examinations as second-stage tests. The urine cytology surveillance was found to be useful for two reasons: first, it detected tumors in five out of six cases surveyed by athe system, and second, four cases screened by cytology had tumors curable by transurethral operation, while other cases underwent cystectomy. Calculated average latent periods from the first and last exposure was 26.4 years (SD = 6.0) and 14.0 years (SD = 6.2), respectively. This time period indicates that the surveillance system should continue to be used for the exposed group even after workers have ceased being exposed.

Abnormal electrocardiograms resembling myocardial infarction in a case of reticulum cell sarcoma

A rare and instructive case of cardiac involvement by reticulum cell sarcoma in a 72-year-old woman was presented. In this case acute myocardial infarction was suspected on an electrocardiogram but was proved absent, and only scattered tumor infiltration was demonstrated at autopsy.

Bronchial length behavior with respect to lung volume histories in different bronchial sizes in excised dog lungs

The bronchial length behavior of three different-sized segments in seven excised dog lobes was examined in terms of the transpulmonary pressure (PL)-bronchial length relationship and the absolute lung volume (VL)-bronchial length relationship during lung inflation and deflation. The straight bronchi of the right lower lobes were used and the bronchial lengths were measured directly and continuously with a linear displacement transducer which was connected by a thin rod to a wedged bead in the bronchi. From PL 30 to 0 cmH2O, the lengths of proximal, intermediate and distal bronchi from the airway opening decreased by 25.2 +/- 4.0%; 36.5 +/- 10.4%; and 37.0 +/- 11.5% (mean +/- S.D.), respectively. Hysteresis of bronchial length existed in the lung volume histories at the same PL, but not at the same VL. With deflation of lung from PL 30 to 0 cmH2O, the more proximal bronchi less changed their length disproportionately with lung volume. It is suggested that nonhomogeneous expansion between lung parenchyma and the bronchi would be more intense in the proximal bronchi than the distal bronchi in terms of bronchial length.

Isolation and characterization of lysozyme-sensitive mutants of Staphylococcus aureus

Four lysozyme-sensitive mutants were isolated after nitrosoguanidine mutagenesis of a lysozyme-insensitive strain of Staphylococcus aureus. One mutant was sufficiently effective for the isolation of macromolecules, such as plasmid deoxyribonucleic acids, from a cell after lysozyme-induced cell lysis.

Determination of purity and identification of animal sources of insulin in various insulin preparations

Prolonged administration of insulin leads to the formation of insulin-binding antibodies due to contaminant peptides and the animal source of the insulin. It follows that quantitation and identification of these factors are of significant importance in pharmaceutical insulin preparations. The assay and test procedures stipulated in the current pharmacopoeia of various countries, nevertheless, cannot determine either of these effects. In the present study, the content of impurities in insulin preparations was measured by polyacrylamide gel disc electrophoresis and the animal source of insulin identified by amino acid analysis. Assays of 17 commercial insulin preparations by these techniques revealed diversity in purity and animal sources of insulin. The present results suggest potential usefulness of these assay methods and advisability of their adoption not only by the manufacturers but also by the official pharmacopoeia as well.

A conductance stopped-flow study of polyelectrolyte systems. Dynamic conformational change of synthetic macroions and their complexation with neutral polymers

Two dynamic phenomena of polyelectrolyte systems, namely the rapid conformational changes of weak polyelectiolytes (polyacrylic acid (HPAA) and polyethylenimine, induced by pH-jump) and the complexation of HPAA with polyvinylpyrrolidone are first investigated by means of the conductance stopped-flow (kappa-SF) technique. The pH-induced relaxations observed by mixing an aqueous solution of HPAA or polyethylenimine with water containing a tiny amount of alkali or acid, are safely ascribed to the conformational transition of the macroions between the compact "coil" and the stretched "rod" forms. The relaxation times are large at high degrees of neutralization and for "rod" conformation. Tentative values for the thermodynamic parameters of the dynamic conformational changes are obtained and discussed. The reaction rates of the polymer complex formation and dissociation of HPAA with polyvinylpyrrolidone are also determined using the kappa-SF method. The association constant and the rates of formation and dissociation are 1.84 x 10(3) M(-1), 9.4 x 10(4) M(-1) s(-1) and 51 s(-1) at 10 degrees C, respectively. We then derive the thermodynamic parameters from the above results.

Epidemiological study of chromium platers in Japan

A cohort study on platers in Tokyo was carried out using the records of the Tokyo Health Insurance Society of Plating Industry. The type of work and chromium-exposure history of each member of this society was investigated by a questionnaire sent to the manager of each factory. The recovery rate of the questionnaire was 70.5%. Survival information on retired subjects was obtained from the offices of Japanese family registration system ("koseki").As the result, among 889 male chromium platers who were followed up from April 1, 1970 to September 30, 1976, 19 deaths were observed, but there were no cases of lung cancer. The observed number of deaths was only 50% of the expected number, which had been calculated using the annual male mortality by age of Tokyo. In contrast, a slightly higher number of deaths than expected (107%) was observed in the control group consisting of workers selected from the same factories as the chromium platers. Two types of possible error were considered in this study: the first is that deaths from the chromium-exposed group had been incorrectly assigned to the control group, and the second is that the 30% of nonresponders included a significant number of factories where chromium-related deaths had occurred.However, the response for surviving cases on the history of chromium handling is considered to be reliable. Thus it was decided to conduct a further study focusing on those workers alive on October 1, 1976.

Successful Jatene operation for transposition of the great arteries with intact ventricular septum. A case report

A description of a successful Jatene operation in an infant with transposition of the great arteries and intact ventricular septum (Group I of TGA) is presented. It is presently believed that the Jatene operation should not be applied in the patient with TGA and intact ventricular septum. However, this report shows the feasibility of this procedure even for the patient in Group I of TGA.

The apparent buffer value of cerebrospinal fluid in acute hypercapnia

Buffer mechanism of cerebrospinal fluid (CSF) against acute hypercapnia was studied in eighteen dogs. The dynamic response of CSF to a stepwise change of CO2 concentration in inspired gas (room air -- 6% CO2 -- 12% CO2) was observed in eleven dogs, maintaining each condition for two hours. The changes in CSF acidity were less than that in arterial blood, while increases of bicarbonate ion concentration [HCO3-] in CSF were more prominent. Apparent buffer values, delta[HCO3-]/deltapH, were calculated from the results in different levels of CO2 breathing : they were 22.7 slykes from room air to 6% CO2 (step 1), and 39.7 slykes from 6% to 12% CO2 (step 2). Similar experiments were performed in seven dogs, suppressing carbonic anhydrase activity by systemic administration of acetazolamide. Apparent buffer values of CSF were 14.4 slykes in step 1 and 16.0 slykes in step 2. From the result we conclude : 1) that the activity of buffer mechanism of CSF in respiratory acidosis is PCO2 dependent and becomes stronger when PCO2 of CSF increases ; 2) for the explanation of this characteristic buffer mechanism of CSF, participation of carbonic anhydrase is suggested for transport mechanism of bicarbonate ion into CSF.

Radiographic and endoscopic features of colonic ulcers in systemic lupus erythematosus

The radiographic and endoscopic features of the colonic ulcers during the course of a case of systemic lupus erythematosus are illustrated. Barium enema revealed the "collar button" type of penetrating ulcers in the left half of the colon and endoscopy demonstrated multiple round- or oval-shaped discrete ulcers, so-called "punched-out" ulcers with pale mucosa. These findings are compared with those of the reported cases of systemic lupus erythematosus and ulcerative colitis. Steroid and 6-mercaptopurine therapy was effective in this case.

Antibacterial activity of combinations of cefazolin and semisynthetic penicillins

The antibacterial activity of cephalosporin (CS) and semisynthetic penicillins was studied using CS-resistant strains of Escherichia freundii and Proteus morganii. A synergistic growth inhibitory action toward these microorganisms was demonstrated by a qualitative method and confirmed by a quantitative determination.