Calcium plays an important role in the regulation of hepatic branched-chain 2-oxo acid dehydrogenase activity

A fetal haemoglobin variant was noted in a healthy Jamaican infant of mixed African/Chinese extraction. A two-dimensional chromatogram of the soluble tryptic peptides (Tp) showed 2 ‘new’ ones/ One was composed of the last 4 residues of the usually insoluble Tpγ41–59. To permit a tryptic split this required a change of residue γ55 Met to Lys or Arg. The other new Tp contained arginine and was in the position expected for a Tpγ41–55 (55 Arg). As the material was limited it could not be analysed. When after more than 6 years no example of Hb F Kingston had become available it was decided to describe the variant on the basis of the present evidence.     

Inflammatory bowel disease and serum beta-N-acetylhexosaminidase

Serum beta-N-acetylhexosaminidase levels in 49 patients with inflammatory bowel disease (IBD; 23 patients with ulcerative colitis, 10 with Crohn's disease, and 16 with ileostomy after total proctocolectomy) as well as in healthy normal controls were determined. They were found to be significantly elevated in 91% of all patients, disregarding the state of activity of the disease. It seems most likely that activated macrophages are the source of this lysosomal hydrolase in the serum of IBD patients since other theoretical possibilities, like damaged hepatocytes or elevated serum bile acid levels, are not relevant for these patients.     

Nerve growth factor-induced rapid reorganization of microfilaments in PC12 cells: Possible roles of different second messenger systems

Nerve growth factor (NGF) induces in 2 to 10 min the redistribution of F-actin in rat pheochromocytoma PC12 cells. The NGF specificity of this phenomenon was shown by blocking it with anti-NGF antibodies. We used the rapid F-actin redistribution as an assay to study NGF second messenger systems and their inhibition or activation by specific agents. The results show that the NGF-induced effect on the microfilament system of PC12 cells can be specifically inhibited by lithium chloride and neomycin, inhibitors of the phosphoinositol system, but cannot be mimicked by TPA and acetylcholine, the activators of the phosphoinositol system. An increase in the intracellular concentration of cyclic AMP by addition of dBcAMP (but not dBcGMP) caused rapid F-actin redistribution that nonetheless differed from the NGF-induced effect. Changes in the intracellular calcium level did not have any influence on the microfilament system of PC12 cells. The specificity of the inhibition of NGF-induced effects by methylase inhibitors was questionable, since MTA- or SAH-treated PC12 cells acquired an altered morphology even in the absence of NGF or dBcAMP. Using the microfilament- and microtubule-disrupting drugs cytochalasin B and colchicine, we showed that the microtubule system in PC12 cells is required for the initiation of neurite outgrowth and that microfilament-associated filopodial activity does not appear to be necessary.     

Quantitation of CaP2+ fluxes in chick calvaria

This report utilizes an Ussing-type apparatus to quantitative the unidirectional fluxes of Ca²⁺ across the periosteal and endosteal membranes of frontal bones derived from calvaria of 20-day chick embryos. The influx was found to be proportional to the concentration of Ca²⁺ and equal to 0.31 μmoles/cm² per h at a concentration of ultrafiltrable Ca²⁺ of 1.75 mM. There were observable differences in the influx measured from periosteal or endosteal sides. The influx was found to be inversely proportional to decreasing temperature and increasing viscosity. The influx increased to 150% of the control flux when the incubation medium contained iodoacetate at a concentration of 1 mM and increased to 200% of control flux when the endosteum or periosteum was removed. These characteristics support the view that the influx is a passive flow with the integrity of cellular layer a controlling factor. The endosteal efflux was greater by a factor of 2 when compared to the periosteal efflux at 37 °C. When the temperature was reduced to 6 °C the endosteal to periosteal efflux ratio decreased to 1.26 indicating a temperature-sensitive component in the endosteal efflux.     

The flavonoids of tetragonotheca (compositae)

Fifteen flavonols, five aglycones and ten glucosides were isolated from the four species of Tetragonotheca, T. repanda, T. helianthoides, T. texana and T. ludoviciana. Included among the isolated flavonols are four previously unreported 7-O-glucosides, 6-hydroxykaempferol 7-O-glucoside, 6-hydroxykaempferol 6-methyl ether 7-O-glucoside, quercetagetin 6,3′-dimethyl ether 7-O-glucoside and quercetagetin 3,6-dimethyl ether 7-O-glucoside.