Chloramphenicol antibody causing interference in antibody detection and identification tests

Investigation of the serum of three patients with positive antibody detection tests demonstrated the cause in each to be an antibody against chloramphenicol, a bacteriostatic agent used in commercial red blood cell reagents. Washing of these red cells prior to use prevented agglutination. All three examples of anti-chloramphenicol antibody were IgM and were in low titer when tested at room temperature and 37 C in saline. Two of the antibodies bound complement. The possibility of an antibody to an ingredient of the commercial preservative solution should be considered if problems are encountered in tests with unwashed commercial red blood cell reagents.     

Effect of titanium,copper and iron on silicon solar cells

The effect of Ti, Cu and Fe on silicon solar cells has been investigated. Ti severely degrades cell performance above a concentration of 10¹¹ cm^?3. The presence of 2 × 10¹⁴ cm^?3 Ti results in a 63% loss in cell performance and more than an order of magnitude reduction in carrier lifetime. Ti gives rise to two deep levels in Si at Ev + 0.30 eV and Ec ? 0.27 eV. Copper, at concentrations below 10¹⁶ cm^?3, has negligible effect on cell performance and carrier lifetime. Above 10¹⁶ cm^?3 copper occasionally produces a 10–15% loss in cell performance with a noticeable increase in junction excess current. No recombination centers were found due to Cu, instead considerable precipitation in the starting material was observed. Fe begins to hurt the cell performance above a concentration of 2 × 10¹⁴ cm^?3. Iron at 1.7 × 10¹⁵ cm^?3 results in 46% loss in cell efficiency and about an order of magnitude reduction in lifetime. Fe induces a deep level in silicon at Ev + 0.4 eV. The active center density, for both Ti and Fe, is only a very small fraction of the total impurity content in the starting silicon wafer.     

The treatment of pain trigger areas in migraine

In many patients with migraine, several localised areas usually on the scalp or neck can be identified. The local injection of lignocaine one per cent and adrenaline 1/200,000 often leads to considerable relief of the symptoms of migraine including visual phenomena. The common sites of the trigger areas are shown and several uncontrolled case reports of the effect of the treatment are described.     

Genital sex pheromones of ixodid ticks: 1. Evidence of occurrence in anterior reproductive tract of American dog tick,Dermacentor variabilis (Say) (Acari: Ixodidae)

The occurrence of a genital sex pheromone in the anterior reproductive tract of partially fed femaleDermacentor variabilis was demonstrated by extraction and bioassay. A new type of bioassay, the neutered female assay, was developed to test the potency of extracts or chemically defined fractions to stimulate males to copulate. Electrophysiological tests confirmed the ability of males to detect the pheromone with sensilla on their cheliceral digits. Males of bothD. variabilis andD. andersoni exhibited neuronal excitation when stimulated with extracts of theD. variabilis reproductive tissues. The pheromone, which is soluble in methanol, was fractionated and found to contain at least two fractions that stimulated copulation by sexually excited males. Evidently, the pheromone is a mixture of two or more compounds. Histologic, ultrastructural, and histochemical studies suggest the vestibular vagina as the site of genital sex pheromone occurrence, presumably from secretions of the surrounding lobular accessory gland. The identity of the compounds that comprise the pheromone remains unknown.Supported by grants AI10986 and AI10987 from the National Institute of Allergy and Infectious Diseases, National Institute of Health, U.S. Public Health Service, Bethesda, Maryland 20205.     

Sensitivities of ocular tissues to acute pressure-induced ischemia

Intraocular pressure was artificially elevated for eight hours in eight owl monkeys. The first permanent effect (produced at a perfusion pressure of plus 15 mm Hg) was partial necrosis of iris stroma and ciliary processes, associated with microscopic lesions in the photoreceptors and retina pigment epithelium around the disc and in the retinal periphery. At a slightly higher pressure, visual nerve fibers in the retina and optic nerve and their ganglion cells were affected. Simultaneously, the outer retinal layers showed damage to the pigment epithelium, photoreceptors, and other nuclear layers. At even higher pressures, nearly all the other intraocular tissues were affected except for Müller cells, astroglia in the optic nerve head, epithelium of the pars plana, and the pigment cells of the choroid. The possibility is raised of a nonischemic pressure-induced mechanism for destruction of disc astrocytes in human chronic glaucoma.     

Reduction operations for constraint satisfaction

The problem of labeling a set of units in such a way as to satisfy an order-N compatibility relation is discussed and shown to be NP-complete. Some general procedures for reducing size of the compatibility relation are defined, properties of these procedures are derived, and their incorporation into a backtracking process is discussed. Their computational cost and storage requirements are also considered.     

Effectiveness of catalytic archipelagos—II: Random arrays of random islands

Voronoi polygons are used to simulate a random distribution of irregularly shaped catalytic islands. Finite element mathematics is used to determine the catalytic effectiveness of the islands when adsorbed reactants diffuse and disappear by a first order reaction at their boundaries. It is found that the catalytic effectiveness of the islands at any fractional coverage can be estimated reasonably accurately either from asymptotic formulae, valid for certain values of diffusion, adsorption, and reaction constants, or from the equivalent annulus approximation found earlier to be accurate for certain regular arrays of regular islands. The equivalent annulus approximation allows analytic prediction of the catalytic effectiveness for any set of parameter conditions given only the fraction area ratio Γ/Ω. Both of these quantities of which can be determined directly from a photomicrog of a representative sample.     

Kinetics of populations of enterocytes of experimental tumors of the large intestine in rats

To determine whether somatostatin, an inhibitor of glucagon and growth hormone secretion, might be useful as an adjunct to insulin the management of diabetic hyperglycaemia, seven insulin-requiring diabetic men were given somatostatin (100 microgram/h, IV) continuously for 3 days after their diabetes had been treated intensively by diet and insulin on a metabolic ward. During infusion of somatostatin and despite reduction in average insulin dose exceeding 50%, there was improvement in diabetic control as assessed by postprandial hyperglycaemia, 24-h glycosuria and the average daily serum glucose level and its fluctuation; when somatostatin was discontinued, but insulin doses held constant, diabetic control rapidly worsened. No adverse effects were observed. These results indicate that somatostatin plus insulin can be a more effective regimen than insulin alone in controlling diabetic hyperglycaemia. A longer acting and more selective somatostatin preparation may prove useful as an adjunct to insulin in the management of diabetes.