Mitochondrial dysfunction in perinatal asphyxia: role in pathogenesis and potential therapeutic interventions

Molecular and Cellular Biochemistry - Perinatal asphyxia (PA)-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and long-term sequelae such as spastic...     

Preface

Molecular and Cellular Biochemistry -     

Effect of ganglionic stimulating and blocking agents on the fast components of colonic myoelectrical activity in the rat

The presence of two types of fast myoelectrical activities, medium fast activity and fast activity, has been demonstrated previously in the electromyogram of colon in normal children and in the rat by the authors. An absence of medium fast activity in Hirschsprung's disease and in experimental aganglionosis of colon in the rat has also been described. In the present study the fast components of colonic myoelectrical activity were analysed during the procedures affecting ganglionic transmission. It was observed that ganglionic stimulants, such as balloon inflation, and intra-arterial injections of acetylcholine and small amounts of nicotine, increased the spike activity and the frequency of medium fast activity without affecting fast activity. The intra-arterial injections of ganglionic blocking agents, such as nicotine in large amounts and pentolinium tartrate, completely abolished the medium fast activity. These observations suggest that the ganglionic activity is responsible for the genesis of medium fast activity and that the absence of cholinergic ganglionic transmission is the most important single factor for the reported altered electromyogram pattern in aganglionosis.     

Simultaneous saccharification and protein enrichment fermentation of sugar beet pulp

Summary A product with 40 % protein content was obtained from sugar beet pulp (1.25–2.0 mm) in 48 h one stage (simultaneous) saccharification/fermentation process under optimized conditions using a specific enzyme mixture andCandida tropicalis strain, also saving about 40 % enzymes in comparison to a 2-stage process.     

Experimental study of physiological pulsatile flow past valve prostheses in a model of human aorta--I. Caged ball valves

Pulsatile flow development past a caged ball valve in a model human aorta was studied using laser Doppler anemometry. Velocity profiles measured in the ascending aorta and in the mid-arch region were strongly influenced by the geometry of the valve at the root of the aorta. Velocity profiles distal to the valve were asymmetric with jet-like flow in the peripheral region having larger velocity magnitudes towards the left lateral wall. In early diastole, a streamwise vortex motion was observed throughout the model aorta with fluid moving towards the downstream direction along the left lateral wall and reversed flow along the right lateral wall. With the caged ball valve at the root of the aorta, no reversed flow was observed along the inner wall of curvature in the mid-arch region.     

Cross reactivity and enzyme sensitivity of immunoaffinity purified Sm/RNP antigens

Immunoaffinity purified Sm/RNP antigens from buffalo and goat liver were studied to determine the role of RNA and proteins towards the antigenicity of Sm and RNP antigens. A more direct approach using enzyme-linked immunosorbent assay on nylon beads has been utilized to look into the problem. The effect of enzyme treatment and the role of RNA and protein fractions in influencing antigenicity have been described. RNA seems to be involved in the maintenance of RNP specific polypeptides in suitable conformation so as to keep them in solution. Removal of RNA leads to insolubilization of RNP specific polypeptides. Antibodies to Sm and RNP antigens have been shown to cross react with poly A containing heterogeneous nuclear ribonucleoprotein with no cross reactivity with thymus RNA or DNA.     

Steady flow development past valve prostheses in a model human aorta—I. Centrally occluding valves

In this paper, laser-Doppler anemometry measurement of steady flow development in a model human aorta has been reported. Studies were made with uniform entry flow at the root of the aorta and our measurements showed the establishment of a pair of Dean vortices in the mid-arch region. Subsequently, the nature of flow development past centrally occluding caged ball valves in the model aorta was investigated. Our studies showed that in the ascending aorta, an asymmetric velocity profile is obtained with larger velocity gradients towards the inner wall of tertiary curvature (anatomically the left lateral wall) with centrally occluding valves. The peripheral flow past these valves prevented the development of Dean vortices in the mid-arch region. The caged ball valves at the root of the aorta had no discernible effect on the velocity profiles in the brachio-cephalic artery.     

Effect of systolic flow rate on the prediction of effective prosthetic valve orifice area

The Gorlin equation for the hemodynamic assessment of valve area is commonly used in cardiac catheterization laboratories. A study was performed to test the prediction capabilities of the Gorlin formula as well as the Aaslid and Gabbay formula for the effective orifice area of prosthetic heart valves. Pressure gradient, flow, and valve opening area measurements were performed on four 27 mm valve prostheses (two mechanical bileaflet designs, St. Jude and Edwards-Duromedics, an Edwards pericardial tissue valve, and a trileaflet polyurethane valve) each mounted in the aortic position of an in vitro pulse duplicator. With the known valve orifice area, a different discharge coefficient was computed for each of the four valves and three orifice area formulas. After some theoretical considerations, it was proposed that the discharge coefficient would be a function of the flow rate through the valve. All discharge coefficients were observed to increase with increasing systolic flow rate. An empirical relationship of discharge coefficient as a linear function of systolic flow rate was determined through a regression analysis, with a different relationship for each valve and each orifice area formula. Using this relationship in the orifice area formulas improved the accuracy of the prediction of the effective orifice area with all three formulas performing equally well.