Endogenous lipolytic activities during autolysis of highly enriched hepatic lysosomes

Highly enriched (50- to 70-fold) fractions of “native” lysosomes were isolated using continuous flow electrophoresis from livers of rats which had not been pretreated with Triton WR-1339. Incubation of lysosomes for 30 min at pH 5.0 in the presence of 5 mM EDTA resulted in a dramatic loss in the content of fatty acids bound to triacylglycerols (137 down to 10 μmol/mg protein) and to phospholipids and an elevation in the level of unesterified fatty acid. Phosphatidylcholine, phosphatidylethanolamine and sphingomyelin concentrations decreased whereas those of lysophosphatidylethanolamine (0.8 up to 8.5% of total lipid-P) and lysophosphatidylcholine (1.9 up to 16.7%) rose in a manner parallel to their respective, fully acylated lipids. Other phospholipids, including phosphatidylinositol, did not change in concentration during incubation. These results indicate that lysosomal phospholipase A, sphingomyelin and triacylglycerol lipase are activated by incubation at acid pH, enabling them to hydrolyze endogenous lysosomal lipids. However, lysosomal phosphatidylinositol-directed phospholipase C is apparently unable to interact with phosphatidylinositol of the lysosomal membrane.     

The assignment of job-attitude items to subscales.

An attitude questionnaire, for use with the personnel of a Great Lakes shipping concern, was constructed using rational judgments to assign items to areas of the questionnaire. The areas were nominally those suggested as invariant by Wherry. The degree of agreement between the rational sort and the areas named from the invariant factor characteristics was determined. Attitude characteristics of the surveyed group as well as mechanical and response artifacts are suggested as providing partial explanations of the differences found. Items identified as critical through use of several item indices are compared to evaluate index utility. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An architecture for a VLSI FFT processor

We propose a new VLSI architecture for an FFT processor. Our architecture uses few processing elements and can be laid out in a mesh-interconnected pattern. We show how to compute the discrete Fourier transform at n points with an optimal speed-up as long as the memory is large enough. The control is shown to be simple and easily implementable in VLSI.     

Geometric conditions for generic structure of multivariable root-loci

Properties of the inverse (A − pBC)⁻¹ are used to characterise the parameters of the infinite zeros of the root-locus of an invertible, multivariable feedback system S(A, B, C) as the solutions of constrained eigenvalue problems and to generate generic subspace conditions that guarantee only integer order infinite zeros in terms of the subspaces in the {A, B}-invariant subspace algorithm.     

Further studies on the effect of aldosterone on electrical resistance of toad bladder

The fall in transepithelial electrical resistance which accompanies aldosterone stimulation of short-circuit current (Isc) in toad urinary bladder has been studied further to evaluate the possible causal role of this response in hormonal stimulation of Na+ transport. A steady-state change in tissue conductance was found to depend upon both the simultaneous stimulation of transport by the steroid and the metabolic state of the tissue. Changes in metabolic state alone did not alter resistance. A sustained increase in Na+ transport, dependent on pretreatment with aldosterone and elicited by addition of glucose, could be obtained without a sustained decrease in resistance. Amiloride, an inhibitor of Na+ uptake, produced changes in Isc that were linearly correlated with its effects on tissue conductance. On the basis of the conductance-Isc relationship with amiloride, the Isc response to aldosterone was about two-fold higher than would be predicted from its effects on conductance alone. Despite the apparent lack of a simple quantitative dependence of the change in Isc on the change in conductance when the response is fully developed, the results suggest that conductance changes may mediate the initial or early stage of the response.     

Hormone changes in relation to the time of fetal death after prostaglandin-induced abortion

The changes in unconjugated estradiol-17beta and estriol, progesterone and chorionic somatomammotropin (HCS) in peripheral plasma have been studied in 18 women at 30-minute intervals following intra-uterine prostaglandin E2 administration for therapeutic termination of second trimester pregnancy. The hormonal changes were related to the time of fetal death detected by the disappearance of fetal heart pulsations. Prostaglandin E2 was given by the intra-amniotic route with urea (5 patients) or with intravenous oxytocin (5 patients), or by the extra-amniotic route with intravenous oxytocin (8 patients). Fetal death occurred rapidly with intra-amniotic PGE2, but usually at a late stage with extra-amniotic PGE2. Three fetuses in the extra-amniotic group died at or just before abortion. A variety of fetal heart changes were noted and the time of fetal death did not appear to influence the time of abortion within each treatment subgroup. Estradiol and estriol showed a sligh but persistent fall over 24 hours prior to induction of abortion. A more rapid fall usually occurred after induction, with a consistent fall around the time of fetal death. Progesterone and HCS usually fell much less before and immediately after fetal death. A marked rise in estradiol sometimes occurred before fetal death, particularly in the intraamniotic PGE2 and urea subgroup. Estriol levels declined more rapidly before than after fetal death, whereas fetal death had less consistent effects on the other hormones. All hormones had usually fallen considerably at the time of abortion, and in some individuals marked fluctuations in hormone levels were seen.     

Curvature effect in microstrip ring resonators

A planar waveguide model for microstrip is used to obtain an improved method of correcting for curvature effects in ring resonators. The extent of the improvement is illustrated by a comparison of experimental measurements and theoretical predictions of microstrip dispersion.     

Production and performance of the inFOCmicroS 20-40-keV graded multilayer mirror

The International Focusing Optics Collaboration for microCrab Sensitivity (InFOCmicroS) balloonborne hard x-ray telescope incorporates graded Pt/C multilayers replicated onto segmented Al foils to obtain the significant effective area at energies previously inaccessible to x-ray optics. Reflectivity measurements of individual foils demonstrate our capability to produce a mass quantity of multilayered foils with a rms roughness of 0.5 nm. The effective area of the completed mirror is 78 and 22 cm2 at 20 and 40 keV, respectively. The measured half-power diameter is 2.0 +/- 0.6 are min (90% confidence). The successful completion of this mirror demonstrates its applicability to future x-ray telescopes such as Constellation-X.