Lipids and stroke: a paradox resolved

The usual methods like hypotension, isovolaemic haemodilution, autologous transfusion and peri-operative blood salvage may significantly reduce the need for homologous blood transfusion in haemorrhagic surgery and also the risk of transmitting infectious agents. Erythropoietin (EPO) is now available and is used to stimulate red cell regeneration in pre-operative autologous blood donation. In acute anaemia, many studies have shown that the stimulation of endogenous erythropoietin production could be very high and accelerate red blood cell production. Taking higher quantities of blood than usual induces a secretion of endogenous erythropoietin, and could be an alternative for the utilization of exogenous EPO in autologous blood donation.     

Investigation of neutrophil signal transduction using a specific inhibitor of phosphatidylinositol 3-kinase

Neutrophils contain a multicomponent NADPH oxidase system that is involved in the production of microbicidal oxidants. Stimulation of human neutrophils with the peptide FMLP activates this respiratory burst enzyme to produce superoxide and also has been shown to result in activation of phosphatidylinositol (Ptdlns) 3-kinase. Treatment of human neutrophils with 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), a potent and specific inhibitor of Ptdlns 3-kinase, resulted in complete inhibition of Ptdlns 3-kinase activity as well as in inhibition of superoxide production in FMLP-treated neutrophils in suspension; FMLP-stimulated oxidant production in adherent cells was also abolished. Treatment of human neutrophils with PMA resulted in production of superoxide without activation of Ptdlns 3-kinase; LY294002 did not block superoxide production in neutrophils exposed to PMA. In addition, LY294002 did not inhibit cellfree NADPH oxidase activation, CD11b-dependent adhesion, actin polymerization in response to FMLP, or FMLP-induced calcium flux. These results suggest that the signal transduction pathway of the FMLP-receptor involves activation of Ptdlns 3-kinase, which is required for subsequent superoxide production induced by the chemotactic peptide. Furthermore, Ptdlns 3-kinase may be located directly upstream of protein kinase C or other protein kinases, which in turn activate the NADPH oxidase system.     

Fabricating biomedical sensors with thin-film technology

Reviews some of the different chemical and physical sensor structures that have been fabricated using thin- and thick-film technology. Individual reports referenced in this article describe the details of the sensor designs and give calibration characteristics and applications. This article illustrates the wide variety of sensors that are possible using thin- and thick-film microelectronic technology. It by no means exhausts the possibilities of what can be done, since only a few materials and applications have been considered. It does, however, point out the great versatility of this type of processing, and sensors fabricated using these microelectronic processes require far less capital expenditure than when full silicon technology is employed     

Allelic loss of 8p sequences in prostatic intraepithelial neoplasia and carcinoma

PURPOSE: The purpose of the study is to report the outcome and postoperative topographic analysis of seven patients who underwent small-diameter, round, eccentric penetrating keratoplasty. METHODS: Seven patients underwent small-diameter, round, eccentric penetrating keratoplasty for a variety of corneal disorders (cataract wound necrosis and dehiscence or fistula, three patients; penetrating keratoplasty wound infection, two patients; corneal rheumatoid melt and perforation, one patient; localized fungal keratitis, one patient). Full-thickness corneal transplants ranged in size from 3.0 to 5.5 mm. The graft wound and sutures spared the visual axis in all cases. Patients were observed for 7 to 42 months (mean, 21 months). All patients had postoperative topographic analysis. One of these also had preoperative analysis. RESULTS: All grafts tectonically were effective in treating the intended condition. Best-corrected visual acuity was 20/30 or better in the four patients without pre-existing corneal transplants or dry eyes; 20/60 and 5/200 in the patients with previous central penetrating keratoplasties; and 20/40 in the patient with rheumatoid melt. There was no clinically significant regular or irregular astigmatism induced centrally by the eccentric graft in the four patients where visual acuity was 20/30 or better. Irregular astigmatism was noted in the other three patients. CONCLUSION: Small-diameter, eccentric penetrating keratoplasties may be used successfully to treat various peripheral corneal disorders. In some cases, this can be performed without inducing high or irregular astigmatism or both centrally.     

Prenatal sonographic diagnosis of Treacher Collins syndrome: a case and review of the literature

We report the prenatal ultrasonographic diagnosis of a fetus with mandibulofacial dysostosis (Treacher Collins syndrome). Sonographic findings included: polyhydramnios, microcephaly, abnormal fetal facial features (slanting forehead, microphthalmos, micrognathia), and abnormal fetal swallowing. A review of the current literature pertaining to prenatal diagnosis of this condition is presented.     

Low- and high-temperature superconducting microwave filters

Stripline and microstrip filters at X-band were designed and fabricated using low- and high-temperature superconductors in quarter-wave, parallel-coupled section configurations. Low-temperature superconducting niobium thin films, deposited on single-crystal sapphire, were used to build to six-pole stripline filters with adjacent passbands and approximately 3 dB crossovers and 1.2% bandwidth. Four- and six-pole microstrip filters were made with in situ epitaxial YBa₂Cu₃O₇ (YBCO) films on LaAlO₃ substrates. All the YBCO filters showed 77 K passbands with clean skirts and high out-of-band rejection. The six-pole filters had adjacent passbands with -28 dB crossovers and 1.5% bandwidth     

Nondestructive characterization of the mechanical strength of diffusion bonds. I. Experimental results

The application of ultrasonic reflectivity for the characterization of a variety of copper diffusion bonds is described. The quality of each diffusion bond has been described by its ultimate tensile strength. Furthermore, fractography of the failed bonds provided information on the relative fraction of bonded areas as well as the geometry of the bonds. This paper provides the experimental results obtained as well as empirical correlations between the quantities determined.     

Performance Effects of Variables in Dynamic Visual Inspection

Three task variables of dynamic visual inspection were examined in laboratory experiments: (V) conveyor-belt velocities, (T) target exposure time and (P) the viewing position of the inspector. Measurements were obtained on both error types in inspection of equally-spaced targets for 36 experimental condition. Task variables V and T provided significant main effects on inspection accuracy and variables T and P had an interacting effect. The probability of correctly identifying a target was found to be describable as l-2.58e^-a where a = 10.587T- 0.0.75/V-0.012/[T+ P²] and the coefficient of determination, R² = 0.88. Inspector's eye motions were recorded and gross eye-motion patterns were identified but none appeared to be directly associated with inspection accuracy. Shifts in the inspection error criterion were observed and described for changes in these task variables. Both inspection speed and accuracy are combined in a cost model. This study shows that different conveyor speeds have better economics with different error costs but that shorter exposure times were never economically better.