Measurement of low frequency magnetic fields from digital cellular telephones

Digital cellular telephones using the GSM (Global System for Mobile Communication) transmit information in bursts of microwaves. This pulsed transmitting mode causes the battery current and currents in the electronics of the apparatus to be pulsed. These pulsed currents produce corresponding pulsed magnetic fields near the phones. A study to determine the magnitude of these fields involved two models of digital telephones. The highest value of the magnetic flux density was 1.8 μT (rms). Bioelectromagnetics 18:184–186, 1997. © 1997 Wiley-Liss, Inc.     

Effect of beta-adrenoceptor blockade on thermoregulation during prolonged exercise

The effect of clinically used equipotent doses of nonselective (beta 1/beta 2; propranolol) and selective (beta 1; atenolol) beta-adrenoceptor blockers on thermoregulation was studied during prolonged exercise in the heat. Oral propranolol (160 mg/day), atenolol (100 mg/day) or matching placebo were taken for 6 days each by 11 healthy young adult caucasian males. Subjects participated in 2 h of block-stepping at a work rate of 54 W in an environmental chamber with a temperature of 33.2 +/- 0.3 degree C dry bulb and 31.7 /+- 0.3 degree C wet bulb, 2 h after ingestion of the final dose of each drug. Both active agents produced similar marked (P less than 0.001) increases in subjective perception of effort, the mechanism of which was not immediately evident from changes in serum electrolytes, blood glucose, blood lactate, or ventilatory parameters. Propranolol did, however, cause a greater rise in serum K+ than placebo (P less than 0.02) and atenolol (P = NS) after exercise. Although rectal and mean skin temperatures were insignificantly altered by beta-adrenoceptor blockade, an increased total sweat production was noted with propranolol (P less than 0.01 vs. placebo) and to a lesser degree atenolol (P = NS vs. placebo) therapy. Analysis of the time course of sweat production showed the propranolol-mediated enhancement of sweating to ensue largely during the initial hour of block-stepping and to be transient in nature. The scientific and clinical implications of this observation will be dependent upon the precise underlying mechanism, a factor not identified by the present study.     

Elevated Fmr1 mRNA levels and reduced protein expression in a mouse model with an unmethylated Fragile X full mutation

The human FMR1 gene contains a CGG repeat in its 5' untranslated region. The repeat length in the normal population is polymorphic (5-55 CGG repeats). Lengths beyond 200 CGGs (full mutation) result in the absence of the FMR1 gene product, FMRP, through abnormal methylation and gene silencing. This causes Fragile X syndrome, the most common inherited form of mental retardation. Elderly carriers of the premutation, defined as a repeat length between 55 and 200 CGGs, can develop a progressive neurodegenerative syndrome: Fragile X-associated tremor/ataxia syndrome (FXTAS). In FXTAS, FMR1 mRNA levels are elevated and it has been hypothesised that FXTAS is caused by a pathogenic RNA gain-of-function mechanism. We have developed a knock in mouse model carrying an expanded CGG repeat (98 repeats), which shows repeat instability and displays biochemical, phenotypic and neuropathological characteristics of FXTAS. Here, we report further repeat instability, up to 230 CGGs. An expansion bias was observed, with the largest expansion being 43 CGG units and the largest contraction 80 CGG repeats. In humans, this length would be considered a full mutation and would be expected to result in gene silencing. Mice carrying long repeats ( approximately 230 CGGs) display elevated mRNA levels and decreased FMRP levels, but absence of abnormal methylation, suggesting that modelling the Fragile X full mutation in mice requires additional repeats or other genetic manipulation.     

Antimicrobial and antiviral activity-guided fractionation from Scutia buxifolia Reissek extracts

Antimicrobial and antiviral activities of the fractions from Scutia buxifolia stem bark and leaves were evaluated. Best antimicrobial results occurred with the ethyl acetate (EA) and n-butanolic (NB) fractions from the leaves against Micrococcus sp. (minimal inhibitory concentration—MIC = 62.5 μg/ml), and NB fraction from stem bark and leaves against Klebsiella pneumoniae and Enterococcus faecalis (MIC = 62.5 μg/ml). The most active fractions were selected and fractioned into silica column to perform an in vitro antibiofilm assay, which evidenced subfractions EA2 and EA3 as the more active against Candida albicans (biofilm inhibitory concentration—BIC = 582 ± 0.01 μg/ml) and Staphylococcus aureus (BIC = 360 ± 0.007 μg/ml), respectively. The NB (selectivity index—SI = 25.78) and the EA (SI = 15.97) fractions from the stem bark, and the EA (SI = 14.13) fraction from the leaves exhibited a potential antiviral activity towards Herpes Simplex Virus type 1 whereas EA2 and EA3 subfractions from leaves (SI = 12.59 and 10.06, respectively), and NB2 subfraction from stem bark (SI = 12.34) maintained this good activity. Phenolic acids and flavonoids (gallic acid, chlorogenic acid, caffeic acid, rutin, isoquercitrin, quercitrin and quercetin) were identified by HPLC and may be partially responsible for the antimicrobial and antiherpes activities observed. The results obtained in this study showed that Scutia buxifolia has antibiofilm and anti-herpetic activities and that these properties are reported for the first time for this species.     

The effect of body temperature on the hunting response of the middle finger skin temperature

The relationship between body temperature and the hunting response (intermittent supply of warm blood to cold exposed extremities) was quantified for nine subjects by immersing one hand in 8°C water while their body was either warm, cool or comfortable. Core and skin temperatures were manipulated by exposing the subjects to different ambient temperatures (30, 22, or 15°C), by adjusting their clothing insulation (moderate, light, or none), and by drinking beverages at different temperatures (43, 37 and 0°C). The middle finger temperature (T _fi) response was recorded, together with ear canal (T _ear), rectal (T _re), and mean skin temperature (Tˉ _sk). The induced mean T _ear changes were −0.34 (0.08) and +0.29 (0.03)°C following consumption of the cold and hot beverage, respectively. Tˉ _sk ranged from 26.7 to 34.5°C during the tests. In the warm environment after a hot drink, the initial finger temperature (T _fi,base) was 35.3 (0.4)°C, the minimum finger temperature during immersion (T _fi,min) was 11.3 (0.5)°C, and 2.6 (0.4) hunting waves occurred in the 30-min immersion period. In the neutral condition (thermoneutral room and beverage) T _fi,base was 32.1 (1.0)°C, T _fi,min was 9.6 (0.3)°C, and 1.6 (0.2) waves occurred. In the cold environment after a cold drink, these values were 19.3 (0.9)°C, 8.7 (0.2)°C, and 0.8 (0.2) waves, respectively. A colder body induced a decrease in the magnitude and frequency of the hunting response. The total heat transferred from the hand to the water, as estimated by the area under the middle finger temperature curve, was also dependent upon the induced increase or decrease in T _ear and Tˉ _sk. We conclude that the characteristics of the hunting temperature response curve of the finger are in part determined by core temperature and Tˉ _sk. Both T _fi,min and the maximal finger temperature during immersion were higher when the core temperature was elevated; Tˉ _sk seemed to be an important determinant of the onset time of the cold-induced vasodilation response. Accepted: 29 April 1997     

Physiology and morphology of the larval sexual pheromone-sensitive neurones in the olfactory lobe of the cockroach, Periplaneta americana

Deutocerebral neurones of larval and adult male cockroaches responding to the female pheromone and its components were recorded extracellularly. No responses to the female pheromone were found in larvae younger than about 10th instar. However, two groups of pheromone-sensitive neurones were recorded in males from 10th instar onwards as in adults. A correlation and factor analysis based on the cells' responses to the pheromone stimuli was used to test the correspondence of these larval and adult cell groups. The recorded larval pheromone-sensitive neurones were stained with cobalt and their morphology compared with that of the adult neurones.     

Postembryonic development of the antennal lobes in Periplaneta americana L.

Summary The postembryonic development of the antennal lobes of Periplaneta americana L. was examined with light- and electron-microscopical methods. There is no difference in the number of glomeruli and neurons in the antennal lobes of larval and adult animals. At hatching, the first larva already possesses the adult number of approximately 125 glomeruli and 500 to 560 deutocerebral neurons in the dorsolateral cell group of each antennal lobe. During postembryonic development the volume of the deutocerebral neurons increases three- to fourfold. The glomeruli of the first larva have about 7 % of the volume of the corresponding adult glomeruli. Since number, pattern, and size ratio of glomeruli (with the exception of the macroglomerulus) are constant in all larval stages and adult animals, it is possible to identify individual glomeruli. During the whole postembryonic development the ordinary glomeruli show a continuous volume increase, which parallels the increase in antennal sensory input. The macroglomerulus develops by way of special growth of two to four neuropil units, but not before the last three to four larval stages and only in males. Its growth precedes the formation of antennal pheromone receptors during the final molt; these receptors are known to project into the macroglomerulus. The development of the macroglomerulus in the last larval stages of the male may be caused by a genetically fixed growth program of specific deutocerebral neurons.Supported by the Deutsche Forschungsgemeinschaft (Scha 291/1)     

Close linkage between X-linked ectodermal dysplasia and a cloned DNA sequence detecting a two allele restriction fragment length polymorphism in the region Xp11-q12

Summary EDA (ectodermal dysplasia, anhidrotic) is an X-linked recessive disorder characterized by hypohidrosis, hypoor anodontia, and hypotrichosis. A possible linkage between the gene for EDA and a number of restriction fragment length polymorphisms (RFLPs) spread over the X chromosome was investigated in two Danish families segregating EDA. No recombination between the gene for EDA and our probe pTAK8, which detects a two allele polymorphism in the region Xp11-q12, was found in nine informative meiotic events (seven of which are phase known), giving a maximal lod score of 2.41 at a recombination fraction of 0.00. This juxtacentromeric location of the gene for EDA agrees well with the linkage data obtained with the other markers used in this study.     

Rational use of Jatropha curcas L. in food and medicine: from toxicity problems to safe applications

Jatropha curcas L. has become an important plant for biorefinery and production of biodiesel. From its ethnobotanical use, the plant is known for several activities which are associated with high toxicity. The latest development in engineering technology enables detoxification of native oil and other parts of the plant for new pharmaceutical purposes. Hence a revised look to the rich metabolic spectra of partly structurally rare secondary compound becomes an interesting field of research to be explored. In this review, we discuss recent developments in the technology of detoxification process and give insight about how this ethnomedicinal plant can be applied to new fields of experimental medicine. The review highlights recent data on biological activities and discusses concepts and strategies for turning a poison plant into a valuable crop with high pharmaceutical potential.     

Increased sequence diversity coverage improves detection of HIV-specific T cell responses

The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss responses to regions where test set and infecting virus differ. In this study, we report the design of a peptide test set with significantly increased coverage of HIV sequence diversity by including alternative amino acids at variable positions during the peptide synthesis step. In an IFN-gamma ELISpot assay, these "toggled" peptides detected HIV-specific CD4(+) and CD8(+) T cell responses of significantly higher breadth and magnitude than matched consensus peptides. The observed increases were explained by a closer match of the toggled peptides to the autologous viral sequence. Toggled peptides therefore afford a cost-effective and significantly more complete view of the host immune response to HIV and are directly applicable to other variable pathogens.