Kinetic studies on the reaction of formaldehyde with diphenyl sulfide. Formaldehyde resins. 99

Kinetic studies on the acid-catalyzed reaction of formaldehyde with diphenyl sulfide (DPS) were carried out in acetic acid in the presence of sulfuric acid. The rate of the initial stage of the reaction was found to be in agreement with the following equation. The relative rates of diphenyl sulfide and its homologous compounds in the reaction with formaldehyde gave a good correlation with BROWN -OKAMOTO 's σ^⊕ values and a large ρ value. The polar effects of substituents of the substituted diphenyl sulfides on the rates were found to be considerably large. From these results a plausible mechanism of the reaction has been deduced.     

Enhancing effects of oral adjuvants on anti-HBs responses induced by hepatitis B vaccine.

Hepatitis B (HB) vaccine is very promising for the prevention of HB infection. There exist, however, some non-responders to current vaccination trials. In this study, taurine, parotin and lithium were selected as adjuvants which can be administered orally. The mechanisms of these three materials as adjuvants and their effects on HB vaccine were investigated in mice. For instance, taurine induced polyclonal antibody production and exhibited adjuvant activity. Although taurine did not have any activity on the proliferation of thymocytes nor stimulate IL-2 production, taurine did induce IL-1 production by macrophages. It was considered that taurine-induced IL-1 would play an essential role in the proliferation and differentiation of B cells. Parotin also induced polyclonal antibody production and exhibited adjuvant activity. These effects of parotin were not affected even if macrophages or T cells were depleted, and parotin itself had an IL-1-like activity. Therefore, it was considered that parotin acted directly on B cells by its IL-1-like activity and mitogenic activity, resulting in the proliferation and differentiation of B cells. Lithium induced neither polyclonal antibody production, nor IL-1 or IL-2 production. However, when given with an antigen, lithium activated the humoral immune system, resulting in the augmentation of antibody production. Oral administration of taurine, parotin and lithium were capable of restoring antibody responses to HB surface antigen (HBsAg) in HBsAg-nonresponder mice. Furthermore, taurine, parotin and lithium enhanced the adjuvant effects of aluminium contained in the present HB vaccine. These observations indicate that use of these oral adjuvants may open new perspectives in the field of human HB vaccination.     

Vinyl polymerization. 120. Mutual copolymerization of p-substituted styrenes through radical mechanism

The radical mutual copolymerization of p-substituted styrenes, such as p-methoxy-, p-chloro-, p-bromo-, p-cyanostyrene, and styrene was carried out with one another at 30°C. in the dark. As initiator, azobisisobutyronitrile was used. The plots of the copolymerization rates against HAMMETT 's σ values showed no linear relationships and the concave curves were obtained therefrom. The relative reactivities of p-substituted styrenes with a definite p-substituted polystyryl radical, which were shown by the reciprocal of monomer reactivity ratio r₁, were plotted against σ values and concave curves were also obtained. The relative reactivities of p-substituted polystyryl radicals with p-substituted styrene were calculated from the ratios r₂ and the propagation rate constants in homopolymerization. the plots of them against σ values gave straight lines with different ρ values, according to the polarity of substituents. These results suggest that polar structures in transition state affected markedly the copolymerization rates. The effect of substituents on resonance stabilization was also quantitatively estimated.     

Active and inactive renin after exercise

Summary The effects of graded exercise on plasma concentrations of active and inactive renin were studied in seven healthy men. Exercise was performed on a cycle ergometer at four different exercise intensities (corresponding to 30%, 50%, 80% and 87% of ) for 10 min each. Concentrations of active renin and total renin after activation by trypsin were measured by direct immunoradiometric assay. Non-trypsin-activated renin concentration (inactive) was obtained by subtraction. Active renin concentrations at 30%, 50%, 80% and 87% of were 1.2, 1.9, 3.1 and 4.6 times higher than the control concentration, respectively. Similar increases in plasma renin concentration, determined by conventional enzymatic assay, were observed at every stage. In contrast, changes in inactive renin concentration were not significant at any stage. Significant increases in noradrenaline concentration were found at every exercise stage, but adrenaline, aldosterone and lactate concentrations were significantly elevated only after exercise at 50%, 80% and 87% of . The similarity between the changes in concentration of active renin and noradrenaline would suggest that sympathetic nerve activity may have been responsible either for the release of active renin or for the conversion of inactive renin to its active form in the kidney.     

No evidence of PEG1/MEST gene mutations in Silver‐Russell syndrome patients

Silver‐Russell syndrome (SRS) is characterized by prenatal and postnatal growth retardation with morphologic anomalies. Maternal uniparental disomy 7 has been reported in some SRS patients. PEG1/MEST is an imprinted gene on chromosome 7q32 that is expressed only from the paternal allele and is a candidate gene for SRS. To clarify its biological function and role in SRS, we screened PEG1/MEST abnormalities in 15 SRS patients from various standpoints. In the lymphocytes of SRS patients, no aberrant expression patterns of two splice variants (α and β) of PEG1/MEST were detected when they were compared with normal samples. Direct sequence analysis failed to detect any mutations in the PEG1/MEST α coding region, and there were no significant mutations in the 5′‐flanking upstream region containing the predicted promoter and the highly conserved human/mouse genomic region. Differential methylation patterns of the CpG island for PEG1/MEST α were normally maintained and resulted in the same pattern as in the normal control, suggesting that there was no loss of imprinting. These findings suggest that PEG1/MEST can be excluded as a major determinant of SRS. © 2001 Wiley‐Liss, Inc.     

Suitable image parameters and analytical method for quantitatively measuring cerebral blood flow volume with phase-contrast magnetic resonance imaging

The aim of this study was to determine suitable image parameters and an analytical method for phase-contrast magnetic resonance imaging (PC-MRI) as a means of measuring cerebral blood flow volume. This was done by constructing an experimental model and applying the results to a clinical application. The experimental model was constructed from the aorta of a bull and circulating isotonic saline. The image parameters of PC-MRI (repetition time, flip angle, matrix, velocity rate encoding, and the use of square pixels) were studied with percent flow volume (the ratio of actual flow volume to measured flow volume). The most suitable image parameters for accurate blood flow measurement were as follows: repetition time, 50 msec; flip angle, 20 degrees; and a 512 x 256 matrix without square pixels. Furthermore, velocity rate encoding should be set ranging from the maximum flow velocity in the vessel to five times this value. The correction in measuring blood flow was done with the intensity of the region of interest established in the background. With these parameters for PC-MRI, percent flow volume was greater than 90%. Using the image parameters for PC-MRI and the analytical method described above, we evaluated cerebral blood flow volume in 12 patients with occlusive disease of the major cervical arteries. The results were compared with conventional xenon computed tomography. The values found with both methods showed good correlation. Thus, we concluded that PC-MRI was a noninvasive method for evaluating cerebral blood flow in patients with occlusive disease of the major cervical arteries.     

Evaluation of "M-point" in hepatic artery to identify left medial segment of liver. Angiographic study

The hepatic arteries of 122 patients were analysed on angiography to identify the left medial segment of the liver. Left medial arterial branches were classified into three types: type I arising from the left hepatic artery on the umbilical portion of the portal vein; type II arising from proximal portion of left hepatic artery before reaching the umbilical portion of the portal vein; type III arising from right hepatic artery. Incidence of each type is 37.2%, 35.8% and 27.0%, respectively. The artery frequently kinks at the right side of the umbilical portion of the portal vein and a total of incidence is 68% and that of each type is 23.5%, 89.8% and 100%, respectively. We call this characteristic kinking point of the left medial arterial branches, the "M-point".