Infantile muscle glycogen storage disease: phosphoglucomutase deficiency with decreased muscle and serum carnitine levels

We report a 5-month-old boy with recurrent vomiting, lethargy, and poor weight gain. He had profound metabolic acidosis and nonketotic dicarboxylic aciduria. The serum and muscle carnitine levels were significantly low (60% and 10% of the control means, respectively), suggesting that the patient had a systemic carnitine deficiency syndrome. The patient showed apparent clinical improvement on oral carnitine administration. A quadriceps muscle biopsy revealed a slight increase in intrafiber lipid droplets and mild accumulation of glycogen in the subsarcolemmal portion. An anaerobic glycolysis in vitro study showed a block after glucose-1-phosphate and before glucose-6-phosphate. Direct measurement of individual glycolytic enzymes in muscle of the patient demonstrated a marked decrease in phosphoglucomutase (PGM) activity (13% of the control mean). The specific defect of PGM activity in this patient suggests that the block in the anaerobic glycolytic pathway is the primary abnormality. PGM deficiency can be added as a newly recognized cause of secondary systemic carnitine deficiency syndromes.     

Contour enhancement of two-dimensional figures observed in the lateral geniculate cells of cats

Responses of lateral geniculate cells to several two-dimensional figures, a square, a triangle and the photograph of a cube, were recorded at various relative positions of the receptive field and the figure. to yield isoresponse contour maps. These all exhibited prominent contour enhancement for each figure.The results were simulated with a computer by modeling the spatial weighting function of the lateral geniculate cell, assuming concentric circular center-surround organization.     

Preventive effects of chrysin on the development of azoxymethane-induced colonic aberrant crypt foci in rats

The modifying effects of dietary feeding with chrysin (5,7-dihydroxyflavone) on the development of azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) were investigated in male F344 rats. We also assessed the effect of chrysin on mitosis and apoptosis in 'normal appearing' crypts. To induce ACF, rats were given two weekly subcutaneous injections of AOM (20 mg/kg body weight). They also received an experimental diet containing chrysin (0.001 or 0.01%) for 4 weeks, starting 1 week before the first dose of AOM. AOM exposure produced a substantial number of ACF (73+/-13/rat) at the end of the study (week 4). Dietary administration of chrysin caused significant reduction in the frequency of ACF: 0.001% chrysin, 37+/-17/rat (49% reduction, P<0.001); and 0.01% chrysin, 40+/-10/rat (45% reduction, P<0.001). In addition, chrysin administration significantly reduced the mitotic index and significantly increased the apoptotic index in 'normal appearing' crypts. These findings might suggest a possible chemopreventive activity of chrysin in the early step of colon tumorigenesis through modulation of cryptal cell proliferation activity and apoptosis.