Influences of breed, sex, and susceptibility to malignant hyperthermia on lipid composition of skeletal muscle and adipose tissue in swine.

OBJECTIVE: To determine influences of breed, sex, and susceptibility to malignant hyperthermia on composition of skeletal muscle and adipose tissue in swine. ANIMALS: 35 male and female swine of German Landrace and Pietrain breeds and of 2 genotypes, normal (MHN) and susceptible to malignant hyperthermia (MHS). PROCEDURE: Pigs were fed a standard diet ad libitum. After attaining body weight of approximately 100 kg, pigs were slaughtered and skeletal (longissimus thoracis and supraspinatus) muscle and adipose tissue (3 sites) specimens were removed. For each specimen, lipids were extracted by chloroform/methanol and fatty acid (FA) pattern, and cholesterol concentration was determined by gas chromatography. RESULTS: The overall lipid contents differed significantly between breeds and genotypes; the MHS Pietrain pigs had the lowest lipid quantities. The relative amounts of saturated FA in all tissues were highest in Landrace pigs (P < 0.05), whereas the relative contents of monoenic FA were lower. In addition, for both breeds, the MHN pigs had significantly higher saturated and lower polyunsaturated FA values in all tissues, compared with MHS pigs. More specifically, MHS females of both breeds had the highest relative amounts of polyunsaturated FA. In general, relative cholesterol contents were found to vary little between identified groups. CONCLUSIONS: These data may indicate that, not only does mutation of the calcium release channel of the sarcoplasmatic reticulum, which occurs in MHS swine, influence secondary changes in lipid composition, but so do hormone concentrations and other genotypic factors. Observed differences in lipid content and FA composition could consequently influence specific membrane properties, such as fluidity and cell signaling.

Method and apparatus for pressure-controlled distension of the lower gastrointestinal tract.

Despite the relevance of visceral perception in the lower gastrointestinal tract to clinical research, especially for diagnosis of functional diseases or neurological derangements of the bowel, precise techniques to evaluate these perceptual processes and mechanical properties of the bowel wall were lacking until recently. Such techniques must include the application of well-defined stimuli and the recording of physiological reactions. A probe was developed which causes minimal discomfort to the subject and is therefore suitable for psychophysical examinations. It can be easily modified for different applications. Stimuli are applied by inflating a balloon, which distends the colon or rectum wall. Prestretching of the balloon material before mounting it on the probe results in monotonic and flat pressure characteristics. Balloon volume is nearly independent from external pressure, within 5% under physiological conditions. Dynamic performance of the balloon is sufficient for studies on the influence of stimulus shape. A microcomputer-controlled pump-system presents precise stimuli within a wide range of volume and inflation rate. A stepping motor is the heart of this system and allows to define exact values for volume and pumping rate without the use of complicated controlling elements. Menu-driven programs allow complex stimulus shapes and sequences. The method and apparatus described above have been successfully used in clinical and basic psychophysiological studies.