TPEN, a Zn2+/Fe2+ chelator with low affinity for Ca2+, inhibits lamin assembly, destabilizes nuclear architecture and may independently protect nuclei from apoptosis in vitro

We used Xenopus egg extracts to examine the effects of TPEN, a chelator with strong affinities for Zn2+, Fe2+, and Mn2+, on nuclear assembly in vitro. At concentrations above 1 mM, TPEN blocked the assembly of the nuclear lamina and produced nuclei that were profoundly sensitive to stress-induced balloon-like 'shedding' of nuclear membranes away from chromatin-associated membranes. TPEN-arrested nuclei were also defective for DNA replication, which could be explained as secondary to the lack of a lamina. Imaging of TPEN-arrested nuclei by field emission in-lens scanning electron microscopy (FEISEM) revealed clustered, structurally-perturbed nuclear pore complexes. TPEN-arrested nuclei were defective in the accumulation of fluorescent karyophilic proteins. All detectable effects caused by TPEN were downstream of the effects of BAPTA, a Ca2+/Zn2+ chelator that blocks pore complex assembly at two distinct early stages. Surprisingly, TPEN-arrested nuclei, but not control nuclei, remained active for replication in apoptotic extracts, as assayed by [32P]-dCTP incorporation into high molecular weight DNA, suggesting that TPEN blocks a metal-binding protein(s) required for nuclear destruction during programmed cell death.     

Image processing with VLSI

The development and implementation of systems for the more complex realtime image processing and scene understanding tasks, such as robot vision and remote surveillance, calls for faster computation than that possible using the traditional serial computer. The advent of VLSI has made feasible the consideration of more specialized processing architectures, designed to support these datarates, while keeping systems compact and relatively cheap. Two approaches are discussed: the use of a programmable processor array, and the customizing of image processing algorithms in silicon. This paper examines designs based upon each approach in the light of the techniques and constraints of VLSI. In particular we describe in some detail an example of a VLSI parallel array processor, the Grid (GEC rectangular image and data processor), and a number of special-purpose CMOS/SOS chips based on systolic design techniques.     

Evidence that intravenously administered alpha-galactosyl carbohydrates reduce baboon serum cytotoxicity to pig kidney cells (PK15) and transplanted pig hearts

Methods of inhibiting the hyperacute antibody-mediated rejection that occurs when pig organs are transplanted into primates have been investigated using the baboon as a potential recipient. Baboons were treated with different regimens that included combinations of (1) splenectomy, (2) pharmacologic immunosuppression (CsA, cyclophosphamide, corticosteroids +/- methotrexate), and (3) intravenous infusion of oligosaccharides. The cytotoxicity of the serum was then assessed on cultures of pig kidney cells (PK15). Unmodified serum caused approximate 65-100% pig cell destruction. Splenectomy and/or pharmacologic immunosuppression, and infusions of dextran, dextrose or mannitol, did not result in any reduction of cytotoxicity. Infusions of melibiose and/or arabinogalactan, both of which have terminal non-reducing alpha-galactose, however, decreased relative PK15 cell damage significantly in a dose-dependent manner. At high concentrations (< or = 50 g/hr), complete inhibition of cytotoxicity was achieved in 4 of 15 baboons. The extracorporeal immunoadsorption of baboon serum utilizing immunoaffinity columns of melibiose also resulted in a significant reduction (of approximately 80%) in cytotoxic effect. In 1 baboon, melibiose and arabinogalactan infusion delayed vascular rejection of a pig cardiac xenograft from 10 min to about 12 hr, at which time the baboon died from the toxic effects of the carbohydrate infusion. These observations (1) add further support to the role that anti-alpha-galactosyl antibodies play in the hyperacute rejection of pig tissues transplanted into primates, and (2) demonstrate that serum cytotoxicity can be reduced by the intravenous infusion of alpha-galactosyl oligosaccharides or by extracorporeal immunoadsorption using these carbohydrates.     

Effects of wearing the Bausch & Lomb SoflensTM while skydiving

The use of Soflenses as a method of ametropic correction and ocular protection while skydiving is explored. The use of the Soflens with and without the addition of protective goggles is compared. Vision is seen to be relatively stable and clear while jumping with the Soflens, yet stability and clarity improve significantly when protective goggles are worn over the Soflenses. Stability and clarity improve significantly when protective turbulence in the facial area increases due to more involved skydiving maneuvers. A definite short-term corneal epithelial disturbance is observed when lenses are blown off the eyes due to wind turbulence.     

Right upper quadrant abdominal pain. Diagnosis in patients without evident gallstones

Right upper quadrant abdominal pain is often of biliary origin. Negative results on an ultrasound examination do not exclude biliary pathology. A logical diagnostic approach to the patient should be based on clues obtained from careful history taking, physical examination, and review of routine laboratory studies. Endoscopy, radiography, and nuclear medicine studies may identify specific causes for pain. The use of sophisticated tests, such as endoscopic retrograde cholangiopancreatography with sphincter manometry, may enable diagnosis in refractory cases. Therapy specific for a correctly diagnosed cause provides rewarding results and avoids unnecessary and unsuccessful procedures.