Effect of microwave irradiated Methanosarcina barkeri DSM-804 on biomethanation

Methanosarcina barkeri DSM-804, a methanogenic bacterium, when exposed to microwave radiation of frequencies ranging from 13.5 to 36.5 GHz, showed faster growth in comparison to the unirradiated bacterial culture. Methane concentration in the biogas generated from the irradiated culture was higher than that from unirradiated one, which was to 76.3% on the 15th day of incubation at a microwave radiation frequency of 31.5 GHz, 10 dbm power when irradiated for 2 h. Microscopic study of pure culture revealed that the cells of M. barkeri were more in number and their cell diameter was enlarged by 20%. Inoculation of the culture in a biogas digester containing a combination of jute waste and vegetable market waste as substrate increased the efficacy of biomethanation and reduced its lag phase significantly.

HPV viral load determination during pregnancy as a possible cervical cancer risk

Pregnancy may be a risk factor for cervical human papillomavirus (HPV) infection due to associated increased hormonal level and immunosuppression. Although a majority of such infections are transient, persistent infection may lead to premalignant/malignant cervical lesion. The viral burden is thought to be an indicator for persistence of the infection and malignant transformation. To assess pregnancy as a risk factor for cervical HPV infection, we compared HPV prevalence and viral load among 25 pregnant women to those of 24 non-pregnant and 28 cervical cancer cases. HPV DNA was detected in the cervical cells by PCR using MY09/MY11 primers. HPV positive cases were retested with a low stringency PCR method to ascertain the viral load. HPV prevalences of 68%, 25% and 89% were observed among pregnant women, non-pregnant women and in the cervical cancer cases, respectively. High viral load was frequently (40%) observed in cervical cancer patients. Median viral copy number/cell did not vary much between the non-pregnant and pregnant women. However, pregnant women had a predominantly moderate viral load whereas the low viral load was more frequent in non-pregnant women. High viral load was found to be associated with the presence of HPV 16 in the cervical cancer cases as compared to pregnant/non-pregnant HPV infected women.

Survival of a patient with endopharyngeal common carotid blow out due to parapharyngeal abscess as an unusual complication of cholesteatoma

Parapharyngeal abscess as a complication of cholesteatoma is an uncommon entity. Endopharyngeal common carotid artery rupture due to parapharyngeal abscess is also uncommon, and these cases usually end fatally. We present a 17-year-old male with parapharyngeal abscess due to cholesteatoma who developed an endopharyngeal common carotid blow out and survived after common carotid ligation without any neurological sequalae.

Egr3 stimulation of GABRA4 promoter activity as a mechanism for seizure-induced up-regulation of GABA(A) receptor alpha4 subunit expression

GABA is the major inhibitory transmitter at CNS synapses. Changes in subunit composition of the pentameric GABA(A) receptor, including increased levels of alpha4 subunit in dentate granule cells and associated functional alterations such as increased zinc blockade of GABA currents, are hypothesized to be critical components of epileptogenesis. Here, we report that the minimal promoter of the human alpha4 subunit gene (GABRA4p), when used to drive reporter gene expression from adeno-associated viral vectors, controls condition-specific up-regulation in response to status epilepticus, defining a transcriptional mechanism for seizure-induced changes in levels of alpha4 subunit containing GABA(A) receptors. Transfection studies in primary hippocampal neurons show that inducible early growth response factor 3 (Egr3) up-regulates GABRA4p activity as well as the levels of endogenous alpha4 subunits. Given that Egr3 knockout mice display approximately 50% less GABRA4 mRNAs in the hippocampus and that increases in alpha4 and Egr3 mRNAs in response to pilocarpine-induced status epilepticus are accompanied by increased binding of Egr3 to GABRA4 in dentate granule cells, our findings support a role for Egr3 as a major regulator of GABRA4 in developing neurons and in epilepsy.

TEM/AFM investigation of size and surface properties of nanocrystalline ceria

A series of ceria nanoparticles were synthesized by using a microemulsion method. The effect of relative concentration of surfactant/water on the size and the surface roughness of ceria nanoparticles was examined using transmission electron microscopy (TEM) and atomic force microscopy (AFM) respectively. The investigation confirmed a relationship between the size and the roughness properties of the nanoceria as a function of the water to surfactant ratio. With increasing dilution of the surfactant, the size distribution became narrow such that average particle size decreased linearly as the ratio increased without affecting lower size threshold of particles (approximately 10 nm). The surface roughness, on the other hand was found to increase with increasing water to surfactant ratio implying diluted surfactant would provide rougher surface of ceria nanoparticles. The information can be used to tailor the adhesion properties of nanoceria by optimizing the size distribution as well as surface roughness as a function of water to surfactant ratio.

Selective anxiolysis produced by ocinaplon, a GABA(A) receptor modulator

Benzodiazepines remain widely used for the treatment of anxiety disorders despite prominent, often limiting side effects including sedation, muscle relaxation, and ataxia. A compound producing a robust anxiolytic action comparable to benzodiazepines, but lacking these limiting side effects at therapeutic doses (an anxioselective agent), would represent an important advance in the treatment of generalized anxiety disorder, and perhaps other anxiety disorders. Here we report that the pyrazolo[1,5-a]-pyrimidine, ocinaplon, exhibits an anxioselective profile in both preclinical procedures and in patients with generalized anxiety disorder, the most common of the anxiety disorders. In rats, ocinaplon produces significant muscle relaxation, ataxia, and sedation only at doses >25-fold higher than the minimum effective dose (3.1 mg/kg) in the Vogel "conflict" test. This anticonflict effect is blocked by flumazenil (Ro 15-1788), indicating that like benzodiazepines, ocinaplon produces an anxiolytic action through allosteric modulation of GABA(A) receptors. Nonetheless, in eight recombinant GABA(A) receptor isoforms expressed in Xenopus oocytes, the potency and efficacy of ocinaplon to potentiate GABA responses varied with subunit composition not only in an absolute sense, but also relative to the prototypical benzodiazepine, diazepam. In a double blind, placebo controlled clinical trial, a 2-week regimen of ocinaplon (total daily dose of 180-240 mg) produced statistically significant reductions in the Hamilton rating scale for anxiety scores. In this study, the incidence of benzodiazepine-like side effects (e.g., sedation, dizziness) in ocinaplon-treated patients did not differ from placebo. These findings indicate that ocinaplon represents a unique approach both for the treatment and understanding of anxiety disorders.

Switching time of nanowire memory

Cadmium sulfide nanowires of 10-nm diameter, electrodeposited in porous anodic alumina films, exhibit an electronic bistability that can be harnessed for non-volatile memory. The current-voltage characteristics of the wires show two stable conductance states that are well-separated (conductances differ by more than 4 orders of magnitude) and long lived (longevity > 1 year at room temperature). These two states can encode binary bits 0 and 1. Here we report measurements of the switching time to switch from the high- to the low-conductance state. These measurements also shed some light on the physical mechanisms underlying the bistability.

Fluorescence Analysis on the Roots of Rauvolfia Serpentina (L.) Benth. Ex Kurz Under UV Radiation

The present study deals with an analysis of the roots of Rauvolfia serpentine (L) Benth. Ex Kurz under ultraviolet radiation and also under daylight. The coarsely powdered roots were treated with various chemical reagents and the characteristic fluorescence patterns emitted were recorded and are reported in this paper. This study was undertaken as a pharmacognostic standardization to ascertain the authenticity of the roots of this plant in its crude form and also to check any adulteration that may be used in trade.

Galactose toxicity in the rat as a model for premature ovarian failure: an experimental approach readdressed

BACKGROUND

The pathophysiological mechanisms underlying premature ovarian failure (POF) are largely unknown. Our objective was to develop a working animal model to explore the pathogenesis of POF. Since galactosaemic women eventually develop POF, we evaluated the potential of experimental galactose toxicity as the proposed model.

METHODS

Pregnant rats were fed pellets supplemented with or without 35% galactose from day 3 of conception continuing through weaning of the litters. Female offspring were evaluated for serum levels of galactose and galactose-1-phosphate, growth rate, onset of puberty, reproductive cyclicity, ovarian complement of follicles, hypothalamo-pituitary-ovarian function and follicular response to gonadotrophins.

RESULTS

Galactose toxicity delayed the onset of puberty and developed a state of hypergonadotrophic hypoestrogenism. The characteristic low FSH levels at weaning followed by pubertal spurts of gonadotrophins and estradiol (E(2)) secretion of the controls was replaced by a sustained high level of FSH and a low level of E(2) under galactose toxicity. The ovary developed with apparently normal or deficient complement of follicles. Ovarian response to exogenous gonadotrophin stimulation was blunted, but the response improved significantly when the stimulation was preceded by pituitary desensitization.

CONCLUSION

Experimental galactose toxicity may serve as a model for exploring some of the basic tenets of POF.

Camptothecin induced mitochondrial dysfunction leading to programmed cell death in unicellular hemoflagellate Leishmania donovani

The parasites of the order kinetoplastidae including Leishmania spp. emerge from most ancient phylogenic branches of unicellular eukaryotic lineages. In their life cycle, topoisomerase I plays a significant role in carrying out vital cellular processes. Camptothecin (CPT), an inhibitor of DNA topoisomerase I, induces programmed cell death (PCD) both in the amastigotes and promastigotes form of L. donovani parasites. CPT-induced cellular dysfunction in L. donovani promastigotes is characterized by several cytoplasmic and nuclear features of apoptosis. CPT inhibits cellular respiration that results in mitochondrial hyperpolarization taking place by oligomycin-sensitive F0-F1 ATPase-like protein in leishmanial cells. During the early phase of activation, there is an increase in reactive oxygen species (ROS) inside cells, which causes subsequent elevation in the level of lipid peroxidation and decrease in reducing equivalents like GSH. Endogenous ROS formation and lipid peroxidation cause eventual loss of mitochondrial membrane potential. Furthermore, cytochrome c is released into the cytosol in a manner independent of involvement of CED3/CPP32 group of proteases and unlike mammalian cells it is insensitive to cyclosporin A. These events are followed by activation of both CED3/CPP32 and ICE group of proteases in PCD of Leishmania. Taken together, our study indicates that different biochemical events leading to apoptosis in leishmanial cells provide information that could be exploited to develop newer potential therapeutic targets.

Novel Thermoplastic Elastomers Based on Acrylonitrile-Butadiene-Styrene Terpolymer (ABS) from Waste Computer Equipment and Nitrile Rubber

Acrylonitrile-butadiene-styrene terpolymer (ABS) is one of the engineering plastics most frequently used as outer casings for computer equipment such as monitors, keyboards and other similar components. In an attempt to recycle, blends of scrap computer plastics (SCP) based on ABS with nitrile rubber (NBR) were prepared and mechanical properties and morphology were studied. Effect of dynamic vulcanization on the properties of 60/40, 70/30, and 80/20 NBR/SCP blends was assessed. These blends show the thermoplastic elastomeric behavior. Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) studies show that the dynamically vulcanized NBR particles are dispersed in the ABS matrix. The thermoplastic elastomeric blends show excellent swelling resistance in IRM # 93 oil.

Atomic Force Microscopy Studies on Morphology and Distribution of Surface Modified Silica and Clay Fillers in an Ethylene-Octene Copolymer Rubber

Topographic and phase imaging in tapping mode atomic force microscopy (TMAFM) has been performed to investigate the effect of surface modification of silica and clay fillers on the morphology and the microdispersion of the filler particles in the rubber matrix. The above fillers have been modified by using surface coating agents like an acrylate monomer (trimethylolpropane triacrylate, TMPTA) or a silane coupling agent (triethoxy vinylsilane, TEVS) followed by electron beam modification at room temperature. Both unmodified and surface modified fillers have been incorporated in an ethylene-octene copolymer rubber. The phase images of the above composites elucidate the reduction in aggregate size due to the filler surface modification, which is more pronounced in the case of silane modification. The results obtained from the section analysis and the histogram of the filler distribution further corroborate the above findings. The corresponding topographic images are characterized by various statistical quantities like roughness parameters and two-dimensional power spectral density (2-D PSD). As compared to the control silica and clay filled rubbers, a noticeable reduction in the surface roughness is observed in the case of modified filled composites. Thus, the whole study based on AFM suggests that the surface modification of the above fillers significantly reduces the filler-filler interaction, which in turn reduces the filler aggregate size and helps in improving the filler dispersion.

Bioeffects of microwave--a brief review

Since the 18th century scientists have been intrigued by the interaction of electromagnetic fields (EMFs) and various life processes. Attention has been focussed on EMFs in different frequency ranges, of which microwave frequency range forms an important part. Microwaves are part of the electromagnetic spectrum and are considered to be that radiation ranging in frequency from 300 million cycles per second (300 MHz) to 300 billion cycles per second (300 GHz), which correspond to a wavelength range of 1 m down to 1 mm. This nonionising electromagnetic radiation is absorbed at molecular level and manifests as changes in vibrational energy of the molecules or heat (Microwaves irradiating the community, Hidden hazards, Bantan Books publisher, Australia, 1991). Identifying and evaluating the biological effects of microwaves have been complex and controversial. Because of the paucity of information on the mechanism of interaction between microwave and biological systems, there has been a persistent view in physical and engineering sciences, that microwave fields are incapable of inducing bioeffects other than by heating (Health Physics 61 (1991) 3). Of late, the nonthermal effects of microwaves on tissue responses are being documented (Physiol. Rev. 61 (1981) 435; Annals of New York Acad. Sci. 247 (1975) 232; J. Microwave Power 14 (1979) 351; Bioelectromagnetics 7 (1986a) 45; Bioelectromagnetics 7 (1986b) 315; Biologic Effects and Health Hazards of Microwave Radiation, Warsaw, Polish Medical Publication (1974) 289; Biologic Effects and Health hazards of the microwave Radiation, Warsaw, Polish Medical Publication (1974) 22; Multidisciplinory perspectives in event-related brain potential research, Washington DC, US Environmental Protection Agency, (1978) 444). The present article is an attempt to familiarise the reader with pertinent information regarding the effects, mainly athermal, of microwave irradiation on biologic systems, especially microorganisms.