Herpes simplex encephalitis: treatment with surgical decompression and cytosine arabinoside

Herpes simplex encephalitis in a 21-year-old man presented as a flu-like illness, followed by inappropriate behaviour, drowsiness and focal neurologic signs. Investigations indicated a lesion in the right temporal lobe. The diagnosis was confirmed by isolation of the virus from a cerebral biopsy. Pronounced clinical improvement was noted when cytosine arabinoside therapy was started in the postoperative period. This report supports the observation by some authors that cytosine arabinoside may be of value in the treatment of herpes simplex encephalitis.     

Age-dependent alterations of DNA synthesis. Terminal deoxynucleotidyl transferase and DNA polymerase activities in bone marrow subpopulations from mice

The decrease of functional capacity of cellular immunity during ageing seems to be due to cellular changes of stem cells, particularly in the growth properties and the cell density in T-cell subsets. We approached this problem at the molecular biological level by quantifying the key enzymes necessary for DNA synthesis in bone marrow cells from mice: deoxynucleotidyl transferase (TdT) and DNA polymerase alpha. The bone marrow cells were fractionated on a discontinuous bovine serum albumin density gradient and the extractable enzyme activities (expressed per 10(8) nucleated cells in the respective fraction) were determined. TdT activity was found to decrease markedly during ageing. Mature animals contain only 34% and senescent animals only 13% of the activity observed in immature mice. From the density distribution analysis it was found that a shift of TdT-containing cells to the lower density occurs. The specific DNA polymerase alpha activity also decreases in bone marrow cells with age. While the overall activity amounts in immature cells to 78 enzyme units/10(8) cells, it decreases in mature cells to 57 units/10(8) cells, and in cells from senescent animals to 36 units/10(8) cells. Density distribution analysis of the cells shows that the highest activity is observed in the low-density fraction. From these experimental data we conclude that in the fractions containing precursor T-cells, a reduced number of proliferating cells is present.     

Studies of androgen production and binding in 13 male pseudohermaphrodites and 13 males with micropenis

We studied androgen production by morphologic and biochemical criteria plus androgen binding by skin fibroblasts in 13 male pseudohermaphrodites and 13 males with micropenis, none of whom had evidence of androgen insensitivity. Seventeen of the 26 patients had evidence of deficient androgen production, suggesting this as the cause of their incomplete virilization in utero. Fibroblasts from all 26 patients demonstrated normal androgen binding and affinity of the steroid for the receptor. Although these results exclude a deficiency of androgen binding in these individuals, other end organ defects are possible. Guidelines for diagnosis and management of such patients are presented.     

Levels of genetic polymorphism: marker loci versus quantitative traits

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species.     

Hydrogen gas sensing of nano-confined Pt/g-C3N4 composite at room temperature

In this study, we report the hydrogen sensing properties of the Pt dispersed graphitic carbon nitride (g-C₃N₄) nanocomposite at room temperature and inert atmosphere. The nanocomposite was synthesized by a wet-chemical approach, where melamine and chloroplatinic acid hexahydrate were used as precursors. The fabrication of the sensor was done by jet nebulizer-based spray pyrolysis setup. Various characterizations were performed for the analysis of the synthesized nanocomposite. Electrical resistance in the presence and absence of the analyte gas was drastically different. The results at different concentrations and film thickness show Pt/g-C₃N₄ to possess good sensitivity towards the hydrogen gas, suggesting that it could be used for reliable hydrogen gas sensing.     

Synthesis, characterization and oxide ionic conductivity of β-type solid solution in bismuth oxide doped with ytterbium oxide binary system

In this study, after doping Yb₂O₃ substance to α -Bi₂O₃ substance in the range of 1% ≤ n ≤ 8% in a series of different mole ratios, heat treatment was performed by applying a cascade temperature rise in the range of 700–790 °C for 48 and 120 h and new phases were obtained in the (Bi₂O₃)_1???x (Yb₂O₃) _x system. After 48 h of heat treatment at 750 °C and 120 h of heat treatment at 790 °C, mixtures containing 1–8% mole Yb₂O₃ formed a tetragonal phase. With the help of XRD, crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. Thermal measurements were made by using a simultaneous DTA/TG system. The total conductivity (σ _T) in the β-Bi₂O₃ doped with Yb₂O₃ system was measured using four-probe d.c. method.     

Th2-mediated host protective immunity to intestinal nematode infections

Despite many years of study, relatively little is known about the effector mechanisms that operate against intestine-dwelling nematodes. Most of the current understanding comes from studies of laboratory model systems in rodents. It is clear that when an intestinal helminth infection takes place the immune system generates a strong Th2-mediated response, which regulates a variety of responses characteristic of helminth infections such as eosinophilia, intestinal mastocytosis and elevated IgE production. The ability to modulate the host's immune response in vivo with cytokine-specific monoclonal antibodies and recombinant cytokines, together with the use of animals with disruption of key genes involved in the immune response, have provided powerful tools with which to dissect the potential effector mechanisms operating. In the absence of a T-cell compartment the host is unable to expel the parasite. If a Th1-dominated response is generated, protective immunity is almost universally compromised. Thus, it it would appear that some aspect of a Th2-mediated response controls effector mechanisms. Although it is clear that for some infections the mast cell appears to be involved in protection, probably through the generation of a non-specific inflammatory response, how these cells become activated remains unclear. Data from infections in transgenic animals suggest that activation is not through the high-affinity receptor for IgE. Such studies also call into doubt the importance of conventional interactions between effector leucocytes and antibody. There is little evidence to support a protective role for eosinophilia in any system. New data also imply that, although interleukin 4 (IL-4) is generally important (and can exert effects independent of an adaptive immune response), it is not always sufficient to mediate protection; other Th2 cytokines (e.g. IL-13) may warrant closer investigation. It is apparent that a number of potential Th2-controlled effector mechanisms (some of which may be particularly important at mucosal surfaces) remain to be explored. Overall, it is likely that worm expulsion is the result of a combination of multiple mechanisms, some of which are more critical to some species of parasite than to others.