Diurnal blood pressure variation and dietary salt in spontaneously hypertensive rats

We have previously reported that high dietary salt exposure significantly increases daytime mean arterial pressure in spontaneously hypertensive rats (SHR) but not in normotensive Wistar-Kyoto (WKY) controls. In the present study, we used a telemetry monitoring system to evaluate the effects of high dietary salt exposure on diurnal variation of mean arterial pressure and heart rate in SHR and WKY rats. After implantation of a radio frequency transducer, SHR and WKY rats were maintained on either high (8%) or basal (1%) salt diets. Hemodynamic values were then analyzed for diurnal variation with the use of a nonlinear data-fitting program. After 2 weeks of dietary exposure, high salt-fed SHR had significantly greater 24-hour mean arterial pressure (156 +/- 3 mmHg) than SHR receiving basal (135 +/- 2 mmHg) and WKY rats receiving high (100 +/- 2 mmHg) or basal (100 +/- 1 mmHg) salt diets. Rhythm analysis indicated significant increases in both daytime and nighttime mean arterial pressure during high salt exposure in SHR. In WKY rats, high salt exposure increased nighttime but not daytime mean arterial pressure, with no net effect on 24-hour mean arterial pressure. High dietary salt exposure significantly decreased heart rate in both SHR and WKY rats, and it did not significantly alter the pattern of diurnal blood pressure or heart rate variation. These results indicate that WKY rats manifest an acute sensitivity to salt ingestion but have compensatory mechanisms sufficient to prevent sustained increases in mean arterial pressure; such mechanisms are lacking in SHR.

Enrichment of DNA fragments for deleted sequences in human genome with nuclease S1 digestion and PCR amplification

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Toxicity and toxicokinetics of MeISP in isolated rat hepatocytes

Toxicity and toxicokinetics of a new organophosphorus insecticide, MeISP, in isolated rat hepatocytes were studied. It was found that at the final concentration of 1.5 mmol/L, MeISP can (1) result in an increase of leakage of intracellular enzymes, alanine amino-transferase (ALT), lactate dehydrogenase (LDH), beta-glucuronidase (beta-GDase) and acid phosphatase (AcP) to the medium in a dose-dependent fashion; (2) give rise to obvious plasma membrane blebbing; (3) rapidly deplete the intracellular GSH and (4) almost completely inhibit the protein synthesis and gluconeogenesis from sodium pyruvate. The kinetics study showed that at the final concentration of 15 mumol/L, MeISP is rapidly metabolized and this process fits the one-compartment model. The metabolism of MeISP in the hepatocytes with phenobarbital-induced microsomal enzymes is accelerated. These results indicate that (1) MeISP has obvious toxicity to isolated rat hepatocytes and isolated hepatocytes provide a suitable system to examine the toxic effects of xenobiotics at the cellular level and (2) MeISP is metabolized mainly by microsomal enzymes.

[An experimental study on cultivation of human trigeminal ganglionic cell in vitro and its sensitivity to infection of herpes simplex virus type 1]

We firstly report an experimental study on the sensitivity of primary cultural human trigeminal ganglionic cells infected by herpes simplex virus type 1 (HSV-1) in different time-points. The results indicate that the neuron of human trigeminal ganglia is the most sensitive cell type, the antigen of HSV-1 replicates rapidly within the cytoplasm and cell nucleus, the fibroblasts and glia cells are infected partly by the virus. Therefore, perhaps the neuron is the main harboring cell type.

Postnatal anti-interferon-gamma treatment prevents pancreatic inflammation in transgenic mice with beta-cell expression of interferon-gamma

beta-Cell-targeted expression of interferon-gamma (IFN-gamma) leads to pancreatitis and immune sensitization to beta-cells. This transgenic model is used to explore the possible role of locally produced IFN-gamma in loss of tolerance to beta-cell-specific antigens in insulin-dependent diabetes mellitus (IDDM). The aim of the present study was to test if postnatal treatment with antibodies against IFN-gamma could inhibit morphological changes in the IFN-gamma transgenic pancreas, even though the transgene is expressed during embryogenesis. Treatment with a monoclonal rat anti-mouse IFN-gamma antibody for 6 weeks, starting from 5 to 7 days of age, completely inhibited IFN-gamma-induced morphological changes in the pancreas, and only a modest inflammatory reaction emerged after prolonged treatment for 12 weeks. The lack of morphological changes may reflect the ability of nonterminally differentiated neonatal pancreatic cells to compensate for transgene-induced pathological alterations occurring in utero prior to the antibody treatment. We conclude that inflammation and altered pancreas morphology in the transgenic mice is the result of the biological actions of IFN-gamma and not by disrupted islet development due to transgene overexpression in the pancreatic beta-cells. Furthermore, our treatment schedule can serve as a model for future intervention studies in the transgenic mice, elaborating the role of IFN-gamma in localized inflammatory reactions, IDDM in particular.

[Comparative study of single strand conformation polymorphism of 4.5S RNA gene in enterobacteria]

A recently developed technique, non-isotopic single strand conformation polymorphism analysis (PCR-SSCP), was applied to study the conserved feature of 4.5S RNA gene in enterobacteria. The 4.5S RNA gene was amplified by the polymerase chain reaction, using the template DNA extracted respectively from five strains of Escherichia coli and three strains of different genera in Enterobacteriaceae, i.e. Proteus vulgaris, Serratia marcescens and Enterobacter aerogenes. The PCR products were then carried out SSCP analysis. The experimental results showed that there seemed to be no detectable differences in the size and single strand conformation of 4.5S RNA genes from above strains, except the negative strand conformation of Enterobacter aerogenes. Thus it can be seen that the secondary structures of 4.5S RNA gene in enterobacteria are quite conservative.

Relative estimates of combination weights, decision criteria, and internal noise based on correlation coefficients

A means by which relative combination weights may be determined is described for a signal detection model in which the decision variable is a weighted linear combination of several independent, normally distributed random variables, Xi's. The first theorem presents the correlation between the binary response variables--signal versus no signal--and the component Xi. The second theorem presents a parallel result for the case that additive internal noise is present. Thus in psychophysical experiments, the relative combination weights may be obtained by correlating the observers' responses and the input random variables. Third, three numerical methods which allow the evaluation of the relative magnitude of the decision criterion and the variance of a hypothetical additive internal noise are considered.

[Restriction endonuclease analysis of Pomona serogroup of Leptospira interrogans]

Restriction Endonuclease Analysis (REA) was performed on DNAs from the type strains of the Pomona serogroup of Leptospira interrogans by using EcoRI and HhaI restriction enzyme, and the electrophoretic patterns obtained were compared with patterns obtained from 27 isolates from pig kidneys collected at abattoirs in Victoria, which belong to Pomona serogroup previous identified by MAT. All of the isolates were identified as serovar Pomona.

An experimental study on acupuncture anti-hemorrhagic shock

The effect of acupuncture at Neiguan (P 6) on regulating hemorrhagic shock in 90 rabbits was observed. All the results suggested that acupuncture at Neiguan could raise blood pressure, protect cardiac pump function, correct the disturbance of secretion and metabolism of humoral factors, reduce blood adhesion to normal level and thus achieve anti-hemorrhagic shock. This study has provided scientific basis for expounding the mechanism of acupuncture in anti-shock.

[The comparative analysis of the complications of extracapsular cataract extraction with and without posterior chamber intraocular lens implantation]

Three-hundred and fourteen eyes that underwent extracapsular cataract extraction (ECCE) were analyzed. ECCE with posterior chamber intraocular lens implantation (PC IOL) was performed in 168 eyes and ECCE alone was performed in 146 eyes. The complications and visual acuity were compared in the two groups. The PC IOL group showed a low incidence of complications. In addition, vitreous loss occurred in 2.38%, cystoid macular edema occurred in 0.6%, and visual acuity recovered to 0.5 or better in 97.62% of the eyes. The incidence of complications in the ECCE group was slightly higher. The postoperative visual acuity in the ECCE group was lower than that in PC IOL group.

[Survey and analysis on correlative factors with CHD in 12,468 pupils in Yimeng mountain area]

The risk factors correlated with congenital heart diseases (CHD) in 12,468 pupils in Yimeng mountain area were surveyed and analysed. The morbidity rate of CHD was 3.05%, which was higher than those of other heart diseases; ventricular septal defect (VSD) was more frequent than other types of CHD. The frequency in pupils in city is higher than in rural areas. In 38 cases with CHD, through analysis (1:1) on the risk of single factor and the progressive regression analysis on compound factors, the results showed that the age of pregnant women (> or = 35 years), the job of mother (chemical worker), the history of coryza in pregnancy (within 3 months), the season of birth (August, September), and the family history of malformation are notably correlated with CHD.

Mutagenicity of the human carcinogen treosulphan, and its hydrolysis product, dl-1,2:3,4-diepoxybutane in mammalian cells

The cytotoxicity and mutagenicity of the human carcinogen, treosulphan, and its hydrolysis product, dl-1,2:3,4-diepoxybutane (DEB), were studied in Chinese hamster ovary, AS52, cells. Treosulphan (0.1-1.0 mM) is toxic and mutagenic at the gpt locus. A strong pH dependence was noted. DEB is cytotoxic and mutagenic at a much lower dose (0.025 mM), but these effects were not affected by pH. The results suggest that the toxic and mutagenic effects of treosulphan are mediated by its hydrolysis product DEB, and that the conversion of treosulphan to DEB is highly pH-dependent.

Thermophilic aerobic process for the treatment of slaughterhouse effluents with protein recovery

A pig slaughterhouse effluent was submitted to laboratory runs in order to assess the potential of the thermophilic aerobic process for the treatment of slaughterhouse and meat processing industry effluents with protein recovery. Experiments were conducted at 45 degrees C, 52 degrees C and 58 degrees C with solids retention times of 6, 12, 18, 24 and 30 h in a semi-continuously fed bioreactor. At 45 degrees C and 52 degrees C, over 90% of the Chemical Oxygen Demand (COD) was removed at all retention times investigated. At 58 degrees C, COD decreased by 86%, with the exception of the 6-h retention time. A biomass containing 70% Gross Protein (GP) was recovered. The optimal specific productivity of GP (0.434 mgGP mgCOD(-1) h(-1)) occurred at 52 degrees C with a 6-h retention time. Biokinetic parameters were evaluated by fitting to appropriate mathematical models. Analysis of the GP composition confirmed that the amino acid levels in the recovered biomass meet most animal requirements.