Abstract Chronic arsenic toxicity (arsenicosis) as a result of drinking arsenic-contaminated groundwater is a major environmental health hazard throughout the world, including India. A lot of ...research on health effects, including genotoxic effect of chronic arsenic toxicity in humans, have been carried out in West Bengal during the last 2 decades. A review of literature including information available from West Bengal has been made to characterize the problem. Scientific journals, monographs, and proceedings of conferences with regard to human health effects, including genotoxicity, of chronic arsenic toxicity have been reviewed. Pigmentation and keratosis are the specific skin diseases characteristic of chronic arsenic toxicity. However, in West Bengal, it was found to produce various systemic manifestations, such as chronic lung disease, characterized by chronic bronchitis, chronic obstructive and/or restrictive pulmonary disease, and bronchiectasis; liver diseases, such as non cirrhotic portal fibrosis; polyneuropathy; peripheral vascular disease; hypertension; nonpitting edema of feet/hands; conjunctival congestion; weakness; and anemia. High concentrations of arsenic, greater than or equal to 200 μg/L, during pregnancy were found to be associated with a sixfold increased risk for stillbirth. Cancers of skin, lung, and urinary bladder are the important cancers associated with this toxicity. Of the various genotoxic effects of arsenic in humans, chromosomal aberration and increased frequency of micronuclei in different cell types have been found to be significant. Various probable mechanisms have been incriminated to cause DNA damage because of chronic arsenic toxicity. The results of the study in West Bengal suggest that deficiency in DNA repair capacity, perturbation of methylation of promoter region of p53 and p16 genes, and genomic methylation alteration may be involved in arsenic-induced disease manifestation in humans. P53 polymorphism has been found to be associated with increased occurrence of arsenic-induced keratosis. Of the various genes involved in the regulation of arsenic metabolism, single-nucleotide polymorphisms of purine nucleoside phosphorylase, in one study, showed increased occurrence of arsenicosis.
Oral tumor specimens (
n=50) from eastern Indian population were studied for the presence of mutations in the H-, K- and N-
ras genes using selective oligodeoxynucleotide hybridization and ...restriction fragment length polymorphism analysis of polymerase chain reaction-amplified products. Mutations in H- and K-
ras genes were observed at a frequency of 28 and 33%, respectively, whereas no N-
ras mutation was noticed.
The FRAXA locus is flanked by three polymorphic STR markers DXS548, FRAXAC1, and FRAXAC2. Allele frequencies of these markers were determined on a population representing the eastern part of India ...comprising of 69 normal controls and 69 unrelated subjects with mental retardation, among whom 21 were fragile X patients. These frequencies were compared with published data on other Indian population and the major populations of the world. The allele and haplotype distribution of the studied population were significantly different in some respects from the major populations of the world. The increase of heterozygosities in fragile X samples (DXS548 67.5%, FRAXAC1 63.5%, FRAXAC2 68.5%) relative to the controls (DXS548 63.3%, FRAXAC1 51.0%, FRAXAC2 67.2%) suggests a multimodal distribution of fragile X associated alleles. Haplotype analyses with DXS548 and FRAXAC1 markers revealed that haplotype distribution in the normal controls and fragile X groups were significantly different, suggesting a weak founder effect.
Polymorphisms associated with genes coding for glutathione S-transferase enzymes are known to influence metabolism of different carcinogens and have been associated with incidence of various types of ...cancer. We have determined the GST M1 and GST T1 'null' genotype frequency in 81 patients with chronic myeloid leukaemia (CML) and 123 racially and geographically matched control individuals by multiplex polymerase chain reaction (PCR). GST M1 null genotype frequencies in CML and controls were 28.4% and 27.7%, respectively. GST T1 null genotype frequencies in CML and controls were 19.8% and 7.3%, respectively. The GST T1 null genotype frequency in CML patients is significantly different from that in controls (odds ratio (OR) 3.12, 95% confidence interval (CI) 1.3-7.45, P=0.008).
This report describes two patients with chronic myeloid leukaemia (CML): one of them developed accelerated phase CML and died 8 years after diagnosis and the other is at the chronic phase. Sequence ...analysis of reverse transcription-polymerase chain reaction products showed the presence of BCR–ABL fusion transcript e19a2. This finding suggests that CML carrying μ-BCR breakpoint may exhibit a clinical course similar to typical CML.
Turbo decoding of quantized data Dasgupta, U.; Georghiades, C.N.
IEEE transactions on communications,
2002-Jan., 2002-01-00, 20020101, Letnik:
50, Številka:
1
Journal Article
Recenzirano
Much of the work on turbo decoding assumes that the decoder has access to infinitely soft (unquantized) channel data. In practice, however, a quantizer is used at the receiver and the turbo decoder ...must operate on finite precision, quantized data. Hence, the maximum a posteriori (MAP) component decoder which was designed assuming infinitely soft data is not necessarily optimum when operating on quantized data. We modify the well-known normalized MAP algorithm taking into account the presence of the quantizer. This algorithm is optimum given any quantizer and is no more complex than quantized implementations of the MAP algorithm derived based on unquantized data. Simulation results on an additive white Gaussian noise channel show that, even with four bits of quantization, the new algorithm based on quantized data achieves a performance practically equal to the MAP algorithm operating on infinite precision data.
An implementation of the IF section of WCDMA mobile transceivers with a set of two chips fabricated in an inexpensive 0.35- mu m two-poly three-metal CMOS process is presented. The transmit/receive ...chip set integrates quadrature modulators and demodulators, wide dynamic range automatic gain control (AGC) amplifiers, with linear-in-decibel gain control, and associated circuitry. This paper describes the problems encountered and the solutions envisaged to meet stringent specifications, with process and temperature variations, thus overcoming the limitations of CMOS devices, while operating at frequencies in the range of 100 MHz-1 GHz. Detailed measurement results corroborating successful application of the new techniques are reported. A receive AGC dynamic range of 73 dB with linearity error of less than +/-2 dB and spread of less than 5 dB for a temperature range of -30 degree C to +85 degree C in the gain control characteristic has been measured. The modulator measurement shows a carrier suppression of 35 dB and sideband/third harmonic suppression of over 46 dB. The core die area of each chip is 1.5 mm super(2).
Background: Diarrhoea is one of the leading causes of under-five childhood morbidity and mortality in India, despite the availability of easy interventions through oral rehydration at the community ...level. The level of knowledge varies from country to country and within the country, further variations exist in state, district and sub district level based on difference in socio-demographic characteristics of the population. And based on these variations, different community needs different health education efforts in its extent and approaches. It was therefore relevant to explore the level of awareness about diarrhoea and its management among the mothers who were the first level of caregivers.
Objective: To assess the level of knowledge about diarrhoea and oral rehydration therapy among the mothers having their children of 6 months to 5 yrs with diarrhea
Materials and methods: It was a facility based cross-sectional descriptive epidemiological study conducted among 62 mothers having their children of 6 months to five years with diarrhoea. Mothers attended a rural hospital under the geographical area of Madhyamgram in North 24 Parganas district of West Bengal, India. Data was collected by face to face interview of the mothers in the outpatient department of the hospital using a pre-designed and pre-tested questionnaire. The analysis was done in Statistical Package for Social Sciences (SPSS), version 20.0 using bivariate and multivariate (multiple logistic regression model) to examine the statistical significance at 95% confidence interval.
Results: Mean knowledge score was 7.8 (Range 0-17). Lower knowledge score group (0-8) accounted to 36 persons (37.1%) and higher knowledge group (9-19) accounted to 26 persons (62.9%). Knowledge about alarming symptoms of the dehydration was significantly poor. At the individual level, literacy of women and their caste were strongly associated with the knowledge about diarrhoea and its management. At the household level, the way of the disposal of household garbage was also strongly associated.
Conclusion: Considering the poor knowledge of the mothers, the study recommends for extensive health education measures widely in the community with a special focus for the illiterate and socio-economically lower groups, and also for the families having the practice of open garbage disposal.
Bangladesh Journal of Medical Science Vol.18(2) 2019 p.267-273
Chronic arsenic exposure is known to produce arsenicosis and cancer. To ascertain whether perturbation of methylation plays a role in such carcinogenesis, the degree of methylation of p53 and p16 ...gene in DNA obtained from blood samples of people chronically exposed to arsenic and skin cancer subjects was studied. Methylation-specific restriction endonuclease digestion followed by polymerase chain reaction (PCR) of gene p53 and bisulfite treatment followed by methylation-sensitive PCR of gene p16 have been carried out to analyze the methylation status of the samples studied. Significant DNA hypermethylation of promoter region of p53 gene was observed in DNA of arsenic-exposed people compared to control subjects. This hypermethylation showed a dose-response relationship. Further, hypermethylation of p53 gene was also observed in arsenic-induced skin cancer patients compared to subjects having skin cancer unrelated to arsenic, though not at significant level. However, a small subgroup of cases showed hypomethylation with high arsenic exposure. Significant hypermethylation of gene p16 was also observed in cases of arsenicosis exposed to high level of arsenic. In man, arsenic has the ability to alter DNA methylation patterns in gene p53 and p16, which are important in carcinogenesis.
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