The significance of spinal cord compression as the initial manifestation of lymphoma

Sex hormones have profound effects on immune responses and may influence the outcome of autoimmune diseases such as rheumatoid arthritis (RA). We investigated the effect of gonadal steroids on the production of interleukin-1 (IL-1) and IL-6, cytokines believed to be important in the pathogenesis of RA. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy male donors and male patients with RA, and were stimulated with lipopolysaccharide (LPS) in the presence of different concentrations of 17-beta-estradiol, progesterone or testosterone. In studies of cells from normal male donors, 17-beta-estradiol at pharmacological concentrations (> or = 10(-6) M) enhanced IL-1 and IL-6 secretion as well as the production of cell-associated IL-1. Progesterone and testosterone at similar concentrations inhibited IL-1 secretion but had no significant effect on IL-6 secretion or on the production of cell-associated IL-1. In studies of male RA donors, 17-beta-estradiol failed to enhance IL-1 or IL-6 secretion and progesterone failed to inhibit IL-1 secretion. The inhibitory effects of testosterone, however, appeared to be similar to that in normal donors. It is suggested that 17-beta-estradiol may promote IL-1 and IL-6 production and release, while gestation hormone, progesterone, and testosterone may inhibit IL-1 release in vivo. These data may partly explain the gender and age differences in the incidence of RA and the development of the disease in men with low and androgen levels.     

Monolithically integrated laser/rear-facet monitor arrays withV-groove for passive optical fiber alignment

An InGaAsP/InP laser monolithically integrated with a rear facet monitor and a fiber V-groove has been demonstrated for the first time. The integrated device incorporates an etched-facet laser fabricated using an in situ, multistep, reactive ion etch process. The integrated V-groove, which is etched directly into the InP substrate, is designed to enable passive alignment of an optical fiber to the active region of the laser. Passive coupling efficiencies of 18% and 8% have been obtained using cleaved multimode and single mode fibers, respectively. Responsivities of the rear facet monitor were as high as 0.49 A/W     

Induction of hyperhydration in rats by IP loading with graded concentrations of NaCl solution

In April 1991, 91 hospitalized patients in Cairo were reported to the Egyptian Ministry of Health with botulism intoxication. To define the spectrum of illness and identify a food vehicle, 45 patients were interviewed and a case-control investigation was conducted among families of 5 hospitalized patients. Clinical specimens and specimens of implicated food were tested for toxin and cultured for Clostridium botulinum. Hospitalized patients had symptoms consistent with botulism; 18 (20%) of 91 reported patients died. Illness was associated with eating faseikh (uneviscerated, salted mullet fish; lower 95% confidence limit of odds ratio = 6.6, P < .001). All 5 case-families purchased faseikh from one shop. Very high levels of type E botulinal toxin were detected in faseikh reported to be purchased from the implicated shop; C. botulinum type E was isolated from cultures of clinical specimens and from the faseikh. This is the first documented outbreak of botulism in Egypt and the largest type E outbreak ever reported.     

Cora valveless pulsatile rotary pump: new design and control

For decades, research for developing a totally implantable artificial ventricle has been carried on. For 4 to 5 years, two devices have been investigated clinically. For many years, we have studied a rotary (but not centrifugal) pump that furnishes pulsatile flow without a valve and does not need external venting or a compliance chamber. It is a hypocycloidal pump based on the principle of the Maillard-Wankel rotary compressor. Currently made of titanium, it is activated by an electrical brushless direct-current motor. The motor-pump unit is totally sealed and implantable, without noise or vibration. This pump was implanted as a left ventricular assist device in calves. The midterm experiments showed good hemodynamic function. The hemolysis was low, but serious problems were encountered: blood components collecting on the gear mechanism inside the rotor jammed the pump. We therefore redesigned the pump to seal the gear mechanism. We used a double system to seal the open end of the rotor cavity with components polished to superfine optical quality. In addition, we developed a control system based on the study of the predicted shape of the motor current. The new design is now underway. We hope to start chronic experiments again in a few months. If the problem of sealing the bearing could be solved, the Cora ventricle could be used as permanent totally implantable left ventricular assist device.     

Role of cholesterol in regulating apolipoprotein B secretion by the liver

The review examines the evidence that the supply of cholesterol available for incorporation into nascent lipoprotein particles exerts a regulatory influence on apolipoprotein (apo) B secretion by the liver. Support for this hypothesis comes both from in vitro experiments and from recent observations in normal subjects and patients with dyslipidemia associated with familial hypercholesterolemia, obesity, noninsulin dependent diabetes mellitus, growth hormone deficiency and cholesteryl ester storage disease. The findings do not negate a role for triglyceride synthesis in determining apoB secretion in very low density lipoprotein, but the inhibitory effects on the latter process of pharmacological blockade of cholesterol synthesis or esterification suggest that it is conditional upon an adequate supply of cholesteryl ester.     

Silicon carbide-toughened zirconia ceramics

Tetragonal zirconia polycrystalline (TZP) ceramics containing SiC reinforcement in the form of fine particles (nano-scale), particles (micro-scale), whiskers and platelets were synthesized by hot-pressing. The effects of morphology and grain size of SiC reinforcement on the strength and fracture toughness at room temperature were investigated. The addition of SiC (in whatever form) caused decreases in strength and toughness at room temperature with the exception of whisker-reinforced materials. Toughness fell off with increasing temperature, but nevertheless retained about one-half of the room-temperature value for that particular SiC reinforcement. However, the whisker- and particle-reinforced materials had higher K _lc values at high temperature than fine particle- or platelet-reinforced materials, with values in excess of 7 MPa m^1/2 at 1000 °C. The microstructure was examined for SiC whisker-reinforced/TZP materials by TEM and HREM, to examine the nature of the whisker/zirconia interface.     

Performance evaluation of the Golay code pulse compression technique

The Center for NDE, Iowa State University, has developed a laboratory prototype Golay code pulse compression system and tested it on a variety of materials. The performance of the system was evaluated in terms of signal-to-noise ratio enhancement (SNRE), resolution, and computation speed. The system's error sources also were discussed. The Golay code pulse compression was simulated on a computer and demonstrated the effective noise suppression. In addition, an equivalent pulse of the Golay code (delta-like pulse) was derived theoretically using a simple ultrasonic inspection model, which demonstrated its equivalence on the output correlated signal. Overall, the pulse compression technique extended the detection range for a given peak power and considerably reduced the system'swhite noise, hence providing enhanced signal-to-noise ratios (SNRs). An average of 30 dB improvement in SNR was obtained from highly energy-absorbent materials such as rubber, plastics, corks (insulation materials), and thick composites using the Golay codes of up to 512 bits. However, the technique did not effectively reduce coherent scattering noises from the coarse grain boundaries in cast stainless steels, Inconel weld metal, and material lay-ups in thin composites. Furthermore, it was found that, depending upon the system's hardware capabilities, the overall performance could be degraded considerably.     

Compatibility and activity of aldesleukin (recombinant interleukin-2) in presence of selected drugs during simulated Y-site administration: evaluation of three methods

The compatibility and biological activity of aldesleukin (a form of recombinant interleukin-2) in the presence of selected i.v. drugs during simulated Y-site administration was studied. Five milliliters of aldesleukin 33,800 IU/mL in 5% dextrose injection was mixed in glass test tubes with 5 mL of each of 19 i.v. drugs prepared at concentrations used in routine clinical practice. The compatibility of the combinations was assessed by visual examination and spectrophotometry at 0, 0.5, 1, and 2 hours after preparation, and bioassays were conducted to determine the activity of aldesleukin in the combinations. Lorazepam was the only drug visually incompatible with aldesleukin. All the secondary drugs were spectrophotometrically compatible with aldesleukin. However, the bioassays showed that the following drugs reduced the activity of aldesleukin: ganciclovir sodium, lorazepam, pentamidine isethionate, prochlorperazine edisylate, and promethazine hydrochloride. Thus, aldesleukin became less biologically active when combined with four drugs for which visual examination suggested compatibility and when combined with five drugs for which spectrophotometry indicated compatibility. Aldesleukin 33,800 IU/mL in 5% dextrose injection lost significant biological activity in the presence of prochlorperazine edisylate, promethazine hydrochloride, lorazepam, ganciclovir sodium, and pentamidine isethionate during simulated Y-site administration. Visual assessment and spectrophotometry may not be valid methods for assessing possible changes in the biological activity of aldesleukin when combined with other agents.