A preliminary trial using multi-target polymerase chain reaction (multiplex PCR) and restriction fragment length polymorphism (PCR-RFLP) on the same feedstuffs to detect tissues of animal origin.

A preliminary study using multi-target polymerase chain reaction (multiplex PCR) and restriction fragment length polymorphism (PCR-RFLP) was done on the same feedstuffs to detect animal tissues. The results of the two methods differ somewhat: PCR-RFLP did not detect any signal in any sample, but multiplex PCR detected a signal in one sample. These findings could be a basis for further investigations.

Natural history of chronic hepatitis C.

BACKGROUND AND AIMS: A comprehensive overview on the course of hepatitis C is not available despite the many studies published. The aim was to review the course and prognostic variables of untreated hepatitis C. METHODS: English-language articles published between January 1989 and December 1997 were identified and data extracted to answer predefined relevant questions. RESULTS: Median chronicization rate, mostly assessed in transfusion-associated hepatitis, was 67%. In retrospective studies, the interval between date of infection and diagnosis of cirrhosis or hepatocellular carcinoma was 20-40 years. Median progression rate from chronic hepatitis to cirrhosis was 27.9% after 8-12 years. Studies obtaining this figure included selected groups of patients and could reflect the worst prognostic segment of the disease. The course of hepatitis C virus infection may be more favourable: cirrhosis rarely or never occurred in young females infected by con-taminated anti-D-immunglobulins; hepatitis was histologically mild in most hepatitis C virus-RNA positive subjects with normal or near normal transminases, predicting non-progressive or very slowly progressive disease; in a population survey from Italy, among 170 infected subjects only 4% had raised transaminases, and none overt liver disease. Increasing age, histological severity, alcohol, possibly male sex and liver iron content were predictors of cirrhosis or increased fibrosis. CONCLUSIONS: Chronicization rate of hepatitis C virus infection is very high. Hepatitis C virus infection can result in a wide prognostic spectrum of liver disease, ranging from cirrhosis and hepatocellular carcinoma to subclinical, nonprogressive disease. Cofactors such as alcohol excess are important in determining the outcome of hepatitis C virus-related chronic liver disease.

Subcellular distribution of dystrophin in isolated adult and neonatal cardiac myocytes.

The subcellular localization of dystrophin was examined in adult rabbit and rat cardiac myocytes with immunofluorescence and at higher resolution with immunogold. The aim was to resolve the conflicting reports on the presence of dystrophin in the transverse tubules (T tubules) of cardiac muscle and to determine its distribution in neonatal myocytes before and during the development of the T tubules. Dystrophin was localized to the peripheral sarcolemma and the T-tubular membrane and was absent from the intercalated disk membranes. In addition, dystrophin localization was followed with immunofluorescence in developing rabbit myocytes at 4 days, 1 wk, and 1 mo after birth. At 4 days of age, T tubules are absent and dystrophin was localized only in the peripheral sarcolemma. Dystrophin was present in the developing T tubules at 1 wk and 1 mo. These results imply that dystrophin is expressed in the T tubules as soon as they develop and confirm the different distribution of dystrophin in the T tubules of cardiac and skeletal muscle.

Dystrophin predominantly localizes to the transverse tubule/Z-line regions of single ventricular myocytes and exhibits distinct associations with the membrane.

Dystrophin is a high molecular weight protein present at low abundance in skeletal, cardiac and smooth muscle and in trace amounts in brain. In skeletal muscle, dystrophin is uniformly distributed along the inner surface of the plasma membrane. Biochemical fractionation studies have shown that all detectable skeletal muscle dystrophin is tightly associated with a complex of wheat germ agglutinin (WGA)-binding and concanavalin A (Con A) binding sarcolemmal glycoproteins. Absence of dystrophin is the primary biochemical defect in patients with Duchenne muscular dystrophy and leads to segmental necrosis of their skeletal myofibers. Although present in similar amounts in normal cardiac and skeletal muscle, the absence of dystrophin from cardiac muscle has less severe effects on the survival of cardiac cells. We have therefore examined whether there are differences in the properties of cardiac and skeletal dystrophin. We report that in contrast to skeletal muscle, cardiac dystrophin is distributed between distinct pools: a soluble cytoplasmic pool, a membrane-bound pool not associated with WGA-binding glycoproteins and a membrane-bound pool associated with WGA-binding glycoproteins. Cardiac dystrophin was not associated with any Con A binding glycoproteins. Immunohistochemical localization studies in isolated ventricular myocytes reveal a distinct punctate staining pattern for dystrophin, approximating to the level of the transverse tubule/Z-line and contrasting with the uniform sarcolemmal staining reported for skeletal muscle fibers. The distinct properties of cardiac dystrophin suggest unique roles for this protein in cardiac versus skeletal muscle function.