Delayed hypersensitivity in the chronic cholera vibrio carrier state in animals with an absence of normal microflora

The development of allergy in germ-free rats in chronic vibriocarriership was studied. The formation of specific delayed type hypersensitivity was found to occur to a limited extent in the animals devoid of normal microflora. The picture of hyperergic inflammation was revealed in the lymph nodes of vibriocarrier rats, the test for specific allergen being positive.     

Supercoiled DNA repair in thymocyte fractions differing in radiosensitivity

Mouse thymocyte fractions were isolated on the basis of buoyant density in a step-gradient of human serum albumin. These fractions were characterized by cell size, radiosensitivity and hydrocortisone sensitivity, and by labelled precursor incorporation into DNA, RNA and proteins. The relative sedimentation of nucleoids in sucrose gradient was also determined. Large and more radioresistant thymocytes were characterized by an increased rate of DNA repair compared with the fraction of radiosensitive small lymphocytes. Nucleoids prepared from the small thymocyte fraction had greater relative sedimentation rates than those derived from large cells. The response of relative sedimentation of nucleoids from large and small thymocyte fractions to ethidium bromide concentration does not permit a conclusion on different superhelix density for DNA in cells of these fractions. At the same time the estimate of the supercoiled domain size for nucleoids of large and small thymocyte fractions showed that in the more radiosensitive small cells domains of greater size were predominant.     

Measles virus infection of cells in perivascular infiltrates in the brain in subacute sclerosing panencephalitis: confirmation by non-radioactive in situ hybridization, immunocytochemistry and electron microscopy

As part of continuing multidisciplinary studies on the neuropathogenesis of subacute sclerosing panencephalitis (SSPE), in situ hybridisation, immunocytochemistry and electron microscopy were used to detect measles virus nucleic acid, protein and nucleocapsids in brain perivascular infiltrates of three cases. Perivascular cuffing cells which contained measles virus nucleic acid and antigens were found in all cases. Infected cuffs occurred predominantly in areas of general parenchymal cell infection and in many of these a high proportion of the infiltrating cells were infected. Other cuffs in these areas were either uninfected or contained only a few infected cells. Occasional infected cells were also seen in cuffs in non-infected areas. In contrast, no specific immunocytochemical reactions or in situ hybridisation for measles virus was observed in brain tissue from a patient with herpes encephalitis. By electron microscopy viral nucleocapsid, consistent with measles virus, was found within the cytoplasm of plasma cells in the inflammatory cuffs in SSPE brain tissue. Possible explanations for our results are that infiltrates become infected on arrival in the CNS or alternatively, that the infected infiltrates reflect a generalised infection of the reticuloendothelial system. The frequent presence of uninfected cuffs favours the former explanation.     

Lithium ion modulation of the neuronal responses evoked by monoaminergic receptor agonists

The authors studied the action of lithium ions on the responses of rat dorsal root ganglion neurons and frog spinal motoneurons evoked by monoamine agonists using the microelectrode technique. Lithium ions reversibly inhibit the depolarizing responses of spinal sensory neurons and motoneurons evoked by activation of muscarinic choline-, alpha 1-adreno-, and 5-hydroxytryptamine2 receptors, but enhance the hyperpolarizing neuronal responses evoked by activation of 5-hidroxytryptamine1A receptors.     

ENHANCED MULTIOBJECTIVE OPTIMIZATION TECHNIQUE FOR MULTIDISCIPLINARY DESIGN

An enhanced multiobjective formulation technique, capable of emphasizing specific objective functions during the optimization process, has been demonstrated on a complex multidisciplinary design application. The Kreisselmeier - Steinhauser (K-S) function approach, which has been used successfully in a variety of multiobjective optimization problems, has been modified using weight factors which enables the designer to emphasize specific design objectives during the optimization process. The technique has been implemented in two distinctively different problems. The first is a classical three bar truss problem and the second is a high-speed aircraft (a doubly swept wing-body configuration) application in which the multiobjective optimization procedure simultaneously minimizes the sonic boom and the drag-to-lift ratio (C_D/C_L) of the aircraft while maintaining the lift coefficient within prescribed limits. The results are compared with those of an equally weighted K-S multiobjective optimization. Results demonstrate the effectiveness of the enhanced multiobjective optimization procedure.     

Prototype e-cigarette and the capillary aerosol generator (CAG) comparison and qualification for use in subchronic inhalation exposure testing

Our objective was to evaluate the suitability of using a capillary aerosol generator (CAG) instead of using e-cigarette devices in 90-day or longer inhalation studies. Aerosol characteristics for both the CAG (which uses heat to produce a condensation aerosol) and e-cigarette generators have been previously reported, but a side-by-side comparison with the identical formulation has not been reported. Aerosols from both devices were analyzed immediately after generation for chemicals in the formulation (propylene glycol [PG], glycerin, water, and nicotine), selected carbonyls (acetaldehyde, acrolein, and formaldehyde) by ultra-performance liquid chromatography with ultraviolet detection (UPLC-UV), and a chemical fingerprint analysis using gas chromatography-mass spectroscopy (GC-MS). Aerosol capture methods for chemical analysis included Cambridge filter pads or two impingers in series each containing solution to trap and stabilize selected carbonyl compounds. Particle size distribution (cascade impactor) and exposure port uniformity (gravimetric) was measured in four rodent inhalation exposure chambers under inhalation study conditions. The aerosol of both generators contained the same known and unknown chemicals. Similar levels of compounds in the formula except for PG were detected in the aerosol of both generators. CAG produced more consistent particulate aerosol than e-cigarette generator and had lower levels of carbonyls primarily due to lower levels of formaldehyde. Exposure port concentrations were consistent and closer to target values with the CAG compared to the e-cigarette aerosol generator. CAG was easier to operate on a daily basis although more difficult to maintain because it required daily cleaning compared to single-use e-cigarettes. CAG was determined to be suitable for use in 90-day or longer inhalation studies.

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