Glucose metabolism in uremia

Formation of CO2 from uniformly labeled 14C-glucose was measured in liver slices from uremic and normal rats. Both CO2 formation and lactate concentration were decreased in the uremic liver slices suggesting an inhibition of glucose oxidation. In addition, a net loss of glucose from the medium in the uremic preparation and a net gain in the normal controls suggested that there was increased nonoxidative utilization in the uremic liver. Such changes could not be explained by differences in glucose availability consequent to alterations in glycogen degradation. The most likely explanation is diversion of glucose into other biosynthetic pathways such as the synthesis of amino acids. In this regard, synthesis of glutamine appeared to be enhanced in uremia. Thus, products of carbohydrate metabolism may provide a potential mechanism for disposition of ammonia and synthesis of amino acids in uremia.

Sequestration and turnover of guinea-pig milk proteins and chicken ovalbumin in Xenopus oocytes

The stability and distribution of proteins within the living cell can be studied using Xenopus laevis oocytes. Microinjection of messenger RNAs and secretory proteins, followed by cell fractionation, shows that transfer of ovalbumin and milk proteins across intracellular membranes of the oocyte only occurs during their synthesis. Thus milk protein primary translation products, made in the wheat germ cell-free system, when injected into oocytes remain in the cytosol and are not recovered within membrane vesicles. Such miscompartmentalized primary milk proteins are rapidly degraded (t 1/2 0.6 +/- 0.1 h). In contrast, processed milk proteins, extracted from oocytes injected with mammary gland RNA, are relatively stable when introduced into the cytosolic compartment (t 1/2 alpha-lactalbumin 20 +/- 8 h, casein A 6 h, casein B 4 h, casein C 8.3 h). The primary ovalbumin product is also stable (t 1/2 22 +/- 9 h). Indirect evidence that rapid degradation of miscompartmentalized milk protein primary translation products may occur in vivo was obtained by the injection of massive amounts of ovalbumin and milk protein mRNA. Under these conditions there is no accumulation of primary milk protein translation products, but a polypeptide resembling the unglycosylated ovalbium wheat germ primary product can be detected in the cytosol. Only the glyclosylated forms of ovalbumin are found in the oocyte membrane vesicle fraction. We discuss the roles played by the presence of detachable signal sequences and the absence of secondary modifications in determining the rate of degradation of primary translation products within the cytosol.

Assembly of smooth muscle myosin into side-polar filaments

The in vitro assembly of myosin purified from calf aorta muscle has been studied by electron microscopy. Two types of filament are formed: short bipolar filament similar to those formed from skeletal muscle myosin, and longer "side-polar" filaments having cross bridges with a single polarity along the entire length of one side and the opposite polarity along the other side. Unlike the case with skeletal myosin filaments, antiparallel interactions between myosin molecules occur along the whole length of side-polar filaments. The side-polar structure may be related to the in vivo form of myosin in vertebrate smooth muscle.

Results of BCG adjuvant immunotherapy in 100 patients with epidermoid carcinoma of the head and neck

One hundred patients with advanced, recurrent, or metastatic squamous cell carcinoma of the head and neck were treated with chemotherapy and BCG as adjuvant immunotherapy. The overall response rate was 35 per cent, and the median duration of response was seventeen weeks. BCG does not prolong duration of remission or survival time.

The location of C-protein in rabbit skeletal muscle

Antibodies to C-protein have been used to label fibres of glycerinated rabbit psoas muscle. The labelling patterns observed in the electron microscope show that C-protein is located on 7 stripes, spaced about 43 nm apart in each half of the A-band. Between two and four C-protein molecules per filament are present at each stripe. The labelling patterns also reveal the existence of two previously unrecognized components of the thick filament present in two further stripes in each half of the A-band. The location of C-protein and these other components accounts for many of the stripes seen in sections of the A-band and in negatively stained A-segments and provides new information on the packing of myosin molecules in the thick filament.

The development, route of migration, and pathogenesis of Crenosoma mephitidis in the skunk (Mephitis mephitis)

Crenosoma mephitidis migrates to the lungs of skunks from the stomach via the liver. Development from the third-stage larva to adult occurs in the lungs. The pathogenesis of the disease and the lesions produced are described.