Congenital constriction band syndrome. Pathophysiology and treatment.

The clinical manifestations of 88 children with congenital constriction band syndrome involvement of the hand were reviewed. Seventy-five of these children had evidence of digital or limb amputations, with 235 upper limb amputations and 138 lower limb amputations. In the hand, digital amputations were most common in the index, middle, and ring fingers, whereas in the foot, amputations of the hallux were most often noted. Band indentation was often present at multiple levels. Proximal bands may be associated with neural compression. Syndactyly was invariably associated with a proximal interdigital sinus or cleft and was frequently associated with distal amputation. Examination of a 27-week gestation stillborn specimen having manifestations of congenital constriction band syndrome demonstrated the intrauterine biologic response to band constriction. The variable clinical manifestations of congenital constriction band syndrome can best be explained as the response of the growing, embryologically defined limb to intrauterine deformation or band-induced compression and ischemia.     

Measurements of the molecular size of the simian virus 40 large T antigen.

A measure of the molecular weight of the large simian virus 40 T antigen was sought by SDS-polyacrylamide gel electrophoresis, random-coil chromatography, and sedimentation-velocity analysis in a density gradient. Large T antigen obtained from a simian virus 40-transformed human cell line either by immunoprecipitation or by standard preparatory methods migrated like a 94,000-molecular-weight (approximately 94K) polypeptide in SDS-gels but was found to have an approximate was observed with T antigen obtained from lytically infected monkey cells. In view of the strong theoretical basis for the guanidine method and the agreement with the sedimentation data, these findings suggest that the molecular weight of this protein is approximately 75 to 80K as opposed to 94 to 100K and, therefore, that considerably less than the entire early region of simian virus 40 is required to encode it. This size estimate is in keeping with earlier results which revealed a normal-size T antigen in cells infected with viable deletion mutants lacking as much as 10% of the early region.     

Acetylation of 13-sophorosyloxydocosanoic acid by an acetyltransferase purified from Candida bogoriensis.

Acetyl-coenzyme A: 13-sophorosyloxydocosanoic acid (Glc2HDA) acetyltransferase was purified 14-fold in low yield from Candida bogoriensis cells. The enzyme catalyzes acetylation of the 6' and 6" positions of the sophorosyl group, producing the 13-[2'-O-beta-D-glucopyranosyl-beta-D-glucopyranosyloxy]-docosanoic acid 6',6"-diacetate (Ac2Glc2HDA) and monoacetate (AcGlc2HDA) in a product ratio of 5:1. Neither the purification steps nor heat denaturation studies indicated separation of the first and second acetylation steps. The acetyltransferase has a molecular weight of about 500,000 as determined by gel filtration on a Sepharose 4-B column. It shows a pH optimum range from 7 to 9, is strongly inhibited by 1 mM concentrations of the sulfhydryl reagents N-ethylmaleimide, p-hydroxymercuribenzoate, and 5,5'-dithiobis(2-nitrobenzoic acid), but only partly inhibited by 10 mM iodoacetamide. It has an apparent Km of 30 muM for acetyl-CoA, utilizes propionyl-CoA at 45% the rate of acetyl-CoA, and utilizes longer chain acyl-CoA derivatives much less efficiently. The critical micelle concentrations of the C. bogoriensis glycolipids in pH 7.7 phosphate buffer were estimated by pinacyanol chloride binding as follows: Glc2HDA, 50 mum; AcGlc2HDA, 30 muM; Ac2Glc2HDA, 12 muM. The Stokes radius of Ac2Glc2HDA micelles was 22 A as estimated by gel filtration on Bio-Gel P-150. Glc2HDA was a much better acceptor than its methyl ester in the acetyltransferase assay. A plateau in the Glc2HDA saturation curve at 50 muM and a corresponding break in the reciprocal plot at this concentration indicate the enzyme utilizes the monomeric form of this lipid as substrate.     

Mechanochemical coupling in spin-labeled, active, isometric muscle

Observed effects of inorganic phosphate (P(i)) on active isometric muscle may provide the answer to one of the fundamental questions in muscle biophysics: how are the free energies of the chemical species in the myosin-catalyzed ATP hydrolysis (ATPase) reaction coupled to muscle force?. Pflugers Arch. 414:73-81) showed that active, isometric muscle force varies logarithmically with [P(i)]. Here, by simultaneously measuring electron paramagnetic resonance and the force of spin-labeled muscle fibers, we show that, in active, isometric muscle, the fraction of myosin heads in any given biochemical state is independent of both [P(i)] and force. These direct observations of mechanochemical coupling in muscle are immediately described by a muscle equation of state containing muscle force as a state variable. These results challenge the conventional assumption mechanochemical coupling is localized to individual myosin heads in muscle.     

Real-time imaging of the dynamics of secretory granules in growth cones

Secretory granules containing a hybrid protein consisting of the regulated secretory protein tissue plasminogen activator and an enhanced form of green fluorescent protein were tracked at high spatial resolution in growth cones of differentiated PC12 cells. Tracking shows that granules, unlike synaptic vesicles, generally are mobile in growth cones. Quantitative analysis of trajectories generated by granules revealed two dominant modes of motion: diffusive and directed. Diffusive motion was observed primarily in central and peripheral parts of growth cones, where most granules diffused two to four orders of magnitude more slowly than comparably sized spheres in dilute solution. Directed motion was observed primarily in proximal parts of growth cones, where a subset of granules underwent rapid, directed motion at average speeds comparable to those observed for granules in neurites. This high-resolution view of the dynamics of secretory granules in growth cones provides insight into granule organization and release at nerve terminals. In particular, the mobility of granules suggests that granules, unlike synaptic vesicles, are not tethered stably to cytoskeletal structures in nerve terminals. Moreover, the slow diffusive nature of this mobility suggests that secretory responses involving centrally distributed granules in growth cones will occur slowly, on a time scale of minutes or longer.     

The discovery of fluoropyridine-based inhibitors of the Factor VIIa/TF complex

The activated Factor VII/tissue factor complex (FVIIa/TF) plays a key role in the formation of blood clots. Inhibition of this complex may lead to new antithrombotic drugs. An X-ray crystal structure of a fluoropyridine-based FVIIa/TF inhibitor bound in the active site of the enzyme complex suggested that incorporation of substitution at the 5-position of the hydroxybenzoic acid side chain could lead to the formation of more potent inhibitors through interactions with the S1'/S2' pocket.     

Solid-phase synthesis of naphthylamidines as factor VIIa/tissue factor inhibitors

Reductive amination followed by acylation of polymer-linked formyl aryl amidines generate combinatorial libraries of aryl amidines 8-13. Potent small molecule naphthylamidine inhibitors 12 (Ki<100 nM) of FVIIa/TF have been discovered and their activity against other serine proteases in the coagulation cascade is reported.     

Improving seedling vigour of indigenous medicinal plants with smoke

The application of smoke and aqueous smoke solutions stimulates seed germination in a number of plant species. This study highlights the effects of aerosol smoke and smoke solutions on the germination and seedling vigour of three South African indigenous medicinal plants Albuca pachychlamys, Merwilla natalensis and Tulbaghia violacea. The vigour index of one-week-old seedlings of all three species examined was increased with the application of dry smoke and smoke extract dilutions, as compared to control treatments. Seedlings of A. pachychlamys germinated with smoke solutions showed a significant (p0.05) gain in bulb and leaf mass (27.9 and 197.6 mg respectively) compared to untreated seedlings (9.9 and 124.7 mg respectively) when grown in vitro for 75 days. The leaf mass of smoke solution-treated seedlings of T. violacea was significantly (p0.05) higher (120.4 mg) than that of untreated seedlings (47.6 mg). Subsequently, the height of seedlings in both species was also significantly (p0.05) greater. Seedlings germinated in water and then transferred to smoke solutions (1:2000) showed enhancement of some of the growth parameters studied. Albuca pachychlamys and T. violacea seeds exposed to aerosol smoke exhibited higher seedling survival percentages than from non-smoked seeds, while no significant effect was observed for M. natalensis seedlings. This investigation shows that the application of smoke technology can be adopted to produce high vigour seedlings.