Motoneurons of M. semitendinosus in domestic and wild pigs. A horseradish peroxidase and cord-survey study.

In domestic and wild pigs motor nuclei of the M. semitendinosus were labelled by retrograde transport of horseradish peroxidase (HRP) from muscle to spinal cord. Further motoneurons in the lumbosacral cord were stained with Luxol-fast-blue and cresyl violet. Motoneurons innervating M. semitendinosus were present in the ventral horns of the last (6th) lumbal and the first sacral cord segments. They were localized within two motor columns lying parallel to each other in the medial and lateroventral position. Both parts of the semitendinosus motor nuclei showed a spindle-like shape with both cranial and caudal enlargements. Localization, extent, and shape of the semitendinosus motor nuclei were similar in domestic and wild pigs. The average motoneuron diameter was larger in domestic than in wild pigs. The lumbosacral cord of the wild pig was thicker than that of the domestic pig. It is suggested that the size of alpha-motoneurons has increased as a result of selective breeding after domestication. This process might correlate with a higher incidence of myopathies in domestic pigs.

Light microscopic lectin histochemistry on celloidin stabilized cryostat sections of rat colon.

Celloidin stabilized pre-epithelial mucus gel (PMG) is stained in cryostat sections of the rat colon for light microscopic lectin histochemistry. Specific sugar residues of the mucins are demonstrated both in the PMG and in the mucin-containing cells of the mucosa.

[In vitro caffeine test on skeletal muscle samples from swine]. / In-vitro-Koffeintest an Skelettmuskelproben von Schweinen.

Excitable porcine gracilis muscle samples were subjected to an in vitro caffeine test. Muscle samples were taken from pig carcasses or as biopsy from anaesthetized and halothane tested pigs. The caffeine threshold of the muscle was determined, which was the caffeine concentration of the bath that produced a contracture of the muscle sample. The in vitro caffeine test is used in human medicine to diagnose malignant hyperthermia susceptibility. In this study, the caffeine test was adapted to the particular demands of skeletal muscle samples taken from pig carcasses. The used method is described and the results from 62 pigs are reported. The in vitro caffeine test is a reliable and good reproducible method to diagnose malignant hyperthermia susceptibility in pigs. The caffeine threshold characterizes the resistance of Ca(2+)-ion-storages in the muscle fibers with a numerical value. The caffeine threshold allows a gradual evaluation of the muscle quality and represents a valuable addition to the halothane test.

Effects of oligosaccharides on functional parameters of the intestinal tract of growing pigs.

Feeding experiments were carried out in growing pigs using topinambur powder or inactivated yeasts as prebiotic additives with an application period of at least 3 weeks. At the end of the experimental periods the animals were killed and segments of the intestinal tract were used for measuring transport physiological parameters and for mucin histochemistry. Jejunal epithelia were mounted in Ussing chambers for measuring electrical tissue parameters, paracellular permeability and short circuit current response to mucosal glucose. Both prebiotics had no effects on basal or forskolin stimulated short circuit currents. Total tissue conductances tended to be higher in response to both prebiotics. Topinambur increased mucosal-to-serosal fluxes of mannitol in the proximal and distal jejunum, which could only be demonstrated for the distal jejunum when inactivated yeasts were fed. Mucosal application of glucose induced higher current responses in jejunal tissues. From histochemistry it could be demonstrated that both prebiotics increased the number of ileal goblet cells and the thickness of the colonic mucosa.

[Skeletal muscle samples from slaughtered bodies of swine in student laboratories for the study of muscle physiology]. / Skelettmuskelproben aus Schlachtkörpern von Schweinen im Praktikum zur Muskelphysiologie.

Viable, excitable and contractile samples from gracilis muscle of pig carcasses were used in our student laboratory of muscle physiology. Samples were taken about 20 minutes after stunning. Sampling, transport of the samples and equipment are described. Some examples of registered isometric contractions are shown.

The thickness of the mucus layer in different segments of the rat intestine.

The thickness of the pre-epithelial mucus layer has been measured in different gut segments of rats kept under normal (ad libitum) feeding conditions, and after 48 h of fasting, using cryostat sections and celloidin stabilization from samples containing luminal contents. The mucus layer of the stomach, duodenum, jejunum, ileum, caecum, proximal colon, colon transversum, distal colon and rectum was studied in five groups of male rats (10, 40, 70 and 150 days of age, and older). Under ad libitum feeding conditions, a distinct and continuous mucus layer, with a thickness of more than 3 microns, was only observed in the colon transversum, in the distal colon, in the rectum and in the stomach. No pre-epithelial mucus layer was observed in the duodenum and jejunum where the glycocalix from the apical membrane of the superficial cells appeared to be in a direct contact with the luminal ingesta. In the ileum, caecum and the proximal colon, the surface epithelium of the mucosa was only partly covered by a mucus layer of highly variable thickness. After 48 h of fasting, a mucus layer of 28.8 +/- 25.6 microns and 93.3 +/- 59.4 microns thickness, respectively, was found in the duodenum and jejunum of adult rats, but no increase in the thickness of the mucus layer was observed in the rat hind gut.

Fatigue of three skeletal muscles in domestic and wild pigs. A comparative study in situ.

The semitendinosus, the gastrocnemius and the soleus muscle were stimulated in situ in young, female domestic pigs (Sus scrofa domestica, German Landrace) and in European wild pigs (Sus scrofa scrofa), by supramaximal impulses via the sciatic nerve. Fatigue indices of the whole muscles were registered during a continuous supramaximal stimulation with square wave impulses (0.3 ms) that were given for 10 s with a frequency of 100 Hz. In domestic pigs, fatigue indices of all three muscles were significantly (p less than 0.001) lower than in wild pigs. The extremely rapid fatigue of domestic pig muscles was remarkably different from that measured in wild pigs, comparing either pigs of nearly the same body weight (FI: 22.7/58.6 for the semitendinosus muscle; 28.5/63.7 for the gastrocnemius muscle; 37.7/81.2 for the soleus muscle), or pigs of nearly the same age (FI: 23.1/58.8 for the semitendinosus muscle; 25.9/65.1 for the gastrocnemius muscle; 33.6/81.4 for the soleus muscle). Doses of anaesthetics needed for appropriate general anaesthesia of young wild pigs were two to three times higher than doses used for domestic pigs. Differences in fiber type composition of the muscles, and alterations in signal transmission characteristics at neuromuscular junctions are discussed as to be associated with the extremely low fatigue resistance of the domestic pig muscles.

Neuromuscular transmission in the gastrocnemius muscle of young domestic and wild pigs.

The gastrocnemius muscle was stimulated in situ in young female domestic pigs (DP, Sus scrofa domestica, German Landrace; n = 24) and in European wild pigs (WP, Sus scrofa scrofa; n = 20), by short (0.1 ms) square-wave impulses via the sciatic nerve. Evoked compound action potentials were recorded from the sciatic nerve, from the Ramus muscularis distalis of the tibial nerve and from the end plate region of the muscle tissue. Maximum nerve conduction velocities (NCV) were 58.8 +/- 10.4 m/s in DP and 77.7 +/- 16.5 m/s in WP. Time of neuro-muscular transmission ("distal latency") for evoked compound action potentials from the Ramus gastrocnemius of the tibial nerve into the gastrocnemius muscle was 2.32 +/- 0.54 ms in DP and only 1.27 +/- 0.25 ms in WP. Electromechanical coupling time intervals in the gastrocnemius muscle were 11.95 +/- 2.26 ms in DP and 9.95 +/- 1.07 ms in WP. Motor end plates were visualized histochemically and classified as of the red, intermediate and white type according to their shape and arborization. High extrajunctional acetylcholinesterase activity was observed in the close vicinity of the junctions of muscles in young DP (3.5 month, 40 kg), which was absent in WP muscles and also in DP muscle at older age.

Comparative lectin-histochemistry on the pre-epithelial mucus layer in the distal colon of conventional and germ-free rats.

The mucin composition of the rat distal colonic pre-epithelial mucus layer (PML) was studied by lectin histochemistry in conventional (CV), and germ-free (GF) rats to define effects exerted by the gut flora. No peanut agglutinin (PNA) binding was observed in the PML of GF rats, while the PML of their CV counterparts showed a considerable PNA linkage, indicating terminal Gal-beta1,3-GalNAc residues. Soybean agglutinin (SBA) and Helix pomatia agglutinin (HPA) stained the PML mucins in CV and in GF rats, indicating terminal GalNAc moieties. A quantitative difference in the Limax flavus agglutinin (LFA) binding capacity was found between CV and GF rats, indicating terminal sialic acid moieties: the staining intensity of bound LFA/ FiTC was higher in CV rats than in GF rats. No linkage of Datura stramonium agglutinin (DSA) and of wheat germ agglutinin (WGA) was found in the PML of GF rats, indicating the absence of terminal GlcNAc, while in CV rats, a clearly marked border was visible next to the luminal content as a "nipple edge" when stained with DSA or WGA. Canavalia ensiformis agglutinin (ConA), indicative for branched mannose, stained PML mucins and goblet cell mucins of GF rat distal colon. In CV rats, both locations were free of ConA binding sites. These results suggest degrading effects, exerted by the gut flora on the rat colonic pre-epithelial mucus layer.

Pre-epithelial mucus layer in the colon of conventional and germ-free rats.

The pre-epithelial mucus layer (PML) and epithelial mucins were studied by mucin histochemistry in 10 microns-thick celloidinstabilized cryostat sections in the proximal and distal colon of conventional and germ-free rats aged 120 and 350 days. No continuous PML was found in the proximal colon. A continuous mucus blanket, of fairly homogenous thickness, was observed in the distal colon, where the PML-thickness was 40 +/- 24 microns at 120 days of age and 44 +/- 22 microns at 350 days of age in conventional rats, and 25 +/- 17 microns (120 days) and 22 +/- 10 microns (350 days) in germ-free rats. The stainability of the PML by periodic acid-Schiff and Alcian Blue at pH 2.5 and 1.0 was stronger in conventional rats than in germ-free rats, indicating higher concentrations of mucosubstances and of acid and sulphated mucins, respectively. The PML of the conventional rat distal colon showed a stratified structure of up to eight sublayers. In the distal colon of germ-free rats, the whole gut wall thickness was reduced 47% compared to the conventional rat (germ-free; 185 +/- 73 microns, conventional: 350 +/- 115 microns). No stratification of the PML was observed. The presence of intestinal microflora obviously had a strong influence on the thickness, compactness, mucin content, mucin composition and structure of the pre-epithelial mucus layer.