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.     

Hyperplastic foci in chronic liver disease: Their proliferative activity assessed by nucleolar organizing region

In the cirrhotic and precirrhotic liver, there may be small foci with increased cellularity and amphophilic cytoplasm. These are microscopic lesions that do not form macroscopically detectable nodules, which differ from the macroscopically apparent nodules of dysplastic nodules. In the present study, we assessed the proliferating activity of 12 hyperplastic foci in 11 patients with cirrhosis or chronic hepatitis, by staining for agyrophilic nucleolar organizing regions (AgNOR). The mean AgNOR count per nucleus in the hyperplastic foci ranged from 0.96 to 1.36 (mean, 1.13; SD 0.12), and from 0.81 to 1.06 (mean, 0.94; SD 0.08) in the controls. The AgNOR count In the hyperplastic foci was significantly higher than that In the controls (P> 30.01). Small hyperplastic foci show Increased proliferative activity. Further study on these foci is required to clarify their relation to hepatocarcinogenesis.     

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.     

Effect of stimulated neutrophils from the synovial fluid of patients with rheumatoid arthritis on lymphocytes—A possible role of increased oxygen radicals generated by the neutrophils

Neutrophils from the synovial fluid (SFN) of 10 patients with active rheumatoid arthritis (RA) were investigated to determine the generation of oxygen intermediates (OI) (O2-, H2O2, OH .), chemiluminescence, and lysosomal enzymes (lysozyme and beta-glucuronidase). Lymphocytes from healthy individuals were cocultured at 37 degrees C for 17 hr with SFN from the patients and the number of OKT4+, OKT8+, and OKT3+ cells and the response to mitogens were determined. A markedly increased OI and slightly elevated lysosomal enzyme levels were observed in SFN from patients. Coculture of lymphocytes with SFN resulted in a decreased number of OKT4+ and OKT8+ cells and a greatly reduced response to Con A and mildly diminished response to PHA, while OKT3+ cells were not affected. The simultaneous addition of superoxide dismutase and catalase restored the impairment of monoclonal antibody reaction and lymphocyte responsiveness almost to control levels. It is suggested that the disturbed immunoreactivity of synovial fluid lymphocytes from RA patients may be due to increased OI generated by stimulated neutrophils.     

Photodegradation behavior of some vinyl ketone copolymers

Photodegradation behavior for copolymers of styrene (St), α-methyl styrene (α-MSt) and methyl methacrylate (MMA) with methyl vinyl ketone (MVK) and phenyl vinyl ketone (PVK) in the presence of air was investigated in the solid state and in solution. Photolysis of St/MVK and St/PVK copolymers proceeded smoothly and an increase of the ketone in the copolymer resulted in an increase of the rate of degradation. Generally, the rate of degradation is faster in St/PVK copolymers than in St/MVK copolymers. It is likely that the degradation of the copolymers takes place mainly through NORRISH type II reaction. It was found that the photolysis of α-MSt/PVK copolymers was retarded considerably as compared with St/PVK copolymers. An unexpected behavior was observed in the case of MMA/MVK or MMA/PVK copolymers. These copolymers were expected to degrade with slow rates; they degraded, however, rapidly. Some experiments were done to explain this phenomenon.     

Nuclear magnetic resonance studies on bacterial copolyesters of 3-hydroxybutyric acid and 3-hydroxyvaleric acid

Copolyesters of 3-hydroxybutyric acid (HB) and 3-hydroxyvaleric acid (HV), P(HB-co-HV), were isolated from Alcaligenes eutrophus and characterized by solution NMR, solid-state ¹³C CP/MAS NMR, and differential scanning calorimetry. The ¹³C CP/MAS NMR analysis was compatible with that of a random copolyester of oxy-(1-methyl-3-oxotrimethylene) ( B ) and oxy-(1-ethyl-3-oxotrimethylene) ( V ) units which adopts a regular conformation of a 2₁ -helix in the solid state throughout a wide range of compositions varying from 0 to 90 mol-% V units. The chain dynamics of P(HB-co-HV) in chloroform was studied by analysis of the ¹³C and ¹H NMR spectra. The carbon-13 spin-lattice relaxation times (T₁) and nuclear Overhauser enhancements (NOE) indicated that the copolyester molecules in chloroform are not rigid but rather flexible. The conformational preferences of the copolyester molecules were determined by analysis of the ¹H NMR spectra.     

PRIMARY MALIGNANT FIBROUS HISTIOCYTOMA OF THE ENDOMETRIUM

Malignant fibrous histiocytoma (MFH) has become one of the most common malignancies occurring in soft tissue. To our knowledge, the present case is the first of MFH occurring in the endometrium. The uterus removed from a 47-year-old woman demonstrated a large multinodular endometrial lesion with gross invasive foci in the myometrium and the left oviduct. Microscopically, the endometrial tumor and the invasive lesions were composed of dense sheets of markedly pleomorphic cells consisting of fibroblast-like cells, histiocyte-like cells, foamy histiocytes, benign appearing multinucleated giant cells resembling either osteoclasts or Touton giant cells, and bizarre tumor giant cells. Some of the tumor cells showed phagocytic activities. The tumor cells were oriented in a random or haphazard fashion and classical storiform and fascicular patterns were not observed. The tumor was diagnosed as MFH consisting exclusively of so-called pleomorphic pattern. The patient is alive without evidence of disease, months following total hysterectomy and bilateral salpingo-oophorectomy.     

Determination of the depth of 50% of maximum ionization, I50, for electron beams by the divided difference method

A new characterization of depth-ionization parameters for electron beams is empirically deduced from our data analysis based on the divided difference method (the DD method), which employs the numerical differential of an ionization curve. The important feature of the present method is that it does not necessarily require normalized percent depth-ionization (NPDI) data. The depth of 50% of maximum ionization, I50, which is an important parameter for electron beam dosimetry, can be deduced from the analysis of an unnormalized (or partial) depth-ionization (UDI) curve obtained over a short interval of depth. The values of I50 determined by the DD method are in agreement to within 0.1 mm for energies of 4, 6, and 9 MeV, compared with the ones determined by the TG-51 protocol method (or the conventional method), and the difference was 0.9 mm for 12 and 15 MeV. The dose at the reference depth, dref, calculated from I50 by the DD method, is found to be in agreement with TG-51 to within 0.1%. The field size dependence of the DD method using UDI data was studied for three field sizes: 6 x 6, 10 x 10, and 20 x 20 cm2. For all energies, the discrepancies of I50 as determined by both methods were 0.9 mm on average for the 6 x 6 cm2 fields and 0.6 mm for the other two field sizes. This dependence was remarkable for 6 x 6 cm2 fields for 12 and 15 MeV, and the discrepancies shown by the DD method were 1.2 mm for 12 MeV and 1.8 mm for 15 MeV, respectively. Since the reference field size in clinical dosimetry is usually 10 x 10 cm2, this dependence will not affect clinical dosimetry. The DD method could be an alternative option for checking beam quality in dose calibration.