Levels of Arsenic, Cadmium, Lead, Manganese and Zinc in Biological Samples of Paralysed Steel Mill Workers with Related to Controls

The determination of essential trace and toxic elements in the biological samples of human beings is an important clinical screening procedure. This study aimed to assess the possible effects of environmental exposure on paralysed male workers (n?=?75) belonging to the production and quality control departments of a steel mill. In this investigation, the concentrations of arsenic, cadmium, lead, manganese and zinc were determined in biological samples (blood, urine and scalp hair samples) of exposed paralysis and non-paralysed steel mill workers. For comparative purposes, unexposed healthy subjects of same age group were selected as referents. The elements in the biological samples were measured by atomic absorption spectrophotometry prior to microwave-assisted acid digestion. The validity of the methodology was checked by the biological certified reference materials. The results indicate that the level understudy elements in all three biological samples were significantly higher in paralysed workers of both groups (quality control and production) as compared to referents (p?相似文献   

Increase in diarrheal disease associated with arsenic mitigation in Bangladesh

Background

Millions of households throughout Bangladesh have been exposed to high levels of arsenic (As) causing various deadly diseases by drinking groundwater from shallow tubewells for the past 30 years. Well testing has been the most effective form of mitigation because it has induced massive switching from tubewells that are high (>50 µg/L) in As to neighboring wells that are low in As. A recent study has shown, however, that shallow low-As wells are more likely to be contaminated with the fecal indicator E. coli than shallow high-As wells, suggesting that well switching might lead to an increase in diarrheal disease.

Methods

Approximately 60,000 episodes of childhood diarrhea were collected monthly by community health workers between 2000 and 2006 in 142 villages of Matlab, Bangladesh. In this cross-sectional study, associations between childhood diarrhea and As levels in tubewell water were evaluated using logistic regression models.

Results

Adjusting for wealth, population density, and flood control by multivariate logistic regression, the model indicates an 11% (95% confidence intervals (CIs) of 4–19%) increase in the likelihood of diarrhea in children drinking from shallow wells with 10–50 µg/L As compared to shallow wells with >50 µg/L As. The same model indicates a 26% (95%CI: 9–42%) increase in diarrhea for children drinking from shallow wells with ≤10 µg/L As compared to shallow wells with >50 µg/L As.

Conclusion

Children drinking water from shallow low As wells had a higher prevalence of diarrhea than children drinking water from high As wells. This suggests that the health benefits of reducing As exposure may to some extent be countered by an increase in childhood diarrhea.     

Accumulation,distribution and toxicological effects induced by cadmium on the development of mangrove plant <Emphasis Type="Italic">Kandelia candel</Emphasis> (L.)

Accumulation and distribution pattern of cadmium (Cd) and its toxic effect on growth of the mangrove plant of young Kandelia candel seedlings have been examined. This study demonstrated that under high concentration of Cd stress, the total biomass of K. candel decreased 41.57% compare to control (CK). At the end of 90 days exposure to 25 mg/l Cd, the average seedlings stem height and leaf number of the K. candel decreased by 30.54 and 42.68%, respectively. The results showed that K. candel seedlings, under the experimental condition, accumulated higher concentration of Cd in their roots (411.29 ± 3.60 mg/kg) when compared to hypocotyls, stems and leaves. More than 95% of Cd was accumulated mainly in roots. The distribution pattern of Cd concentration in K. candel seedlings was found in the following order: roots > hypocotyls > stems > leaves. Based on the leaf symptoms and morphological change of K. candel seedlings under heavy metal stress, this study showed that Cd is phytotoxic to K. candel.     

Prevalence of NDM‐1 carbapenemase in patients with diarrhoea in Pakistan and evaluation of two chromogenic culture media

Aims

To evaluate two chromogenic media, Brilliance CRE and chromID CARBA, with stool samples referred to the Public Health Laboratories Division of the National Institute of Health in Islamabad, and assess the prevalence of carbapenemase‐producing Enterobacteriaceae (CPE) in this population.

Methods and Results

One hundred and fifty‐two stool samples from patients with diarrhoea were referred to the Microbiology Department and were investigated for the presence of CPE using two chromogenic culture media, Brilliance CRE and chromID CARBA. Thirteen patients (8·6%) were found to be colonized with CPE and all produced NDM‐1 carbapenemase. Twelve of these patients (92%) were found to be colonized by culture on chromID CARBA compared with seven (54%) using Brilliance CRE.

Conclusions

If only coloured colonies were considered as presumptive CPE, the sensitivity, specificity and positive predictive value were 54, 23 and 6% for Brilliance CRE and 85, 85 and 36% for chromID CARBA, respectively.

Significance and Impact of the Study

We conclude that Enterobacteriaceae that produce NDM‐1 carbapenemase can be found in patients from all major provinces of Pakistan and that chromID CARBA was the most effective of the two chromogenic media in this setting.     

An efficient and rapid regeneration via multiple shoot induction from mature seed derived embryogenic and organogenic callus of Indian maize (Zea mays L.)

An efficient method for in vitro micro propagation and genetic transformation of plants are crucial for both basic and applied research. Maize is one of the most important cereal crops around the world. Regeneration from immature embryo is hampered due to its unavailability round the year. On the contrary mature embryo especially tropical maize is recalcitrant toward tissue culture. Here we report a highly efficient regeneration (90%) system for maize by using 2 different approaches i.e., embryogenic and organogenic callus cultures. Seeds were germinated on MS medium supplemented with 5 mg/l 2,4-D and 3 mg/l BAP. Nodal regions of 2 wks old seedlings were longitudinally split upon isolation and subsequently placed on callus initiation medium. The maximum frequency of embryogenic callus formation (90%) was obtained on MS medium supplemented with 2 mg/l 2,4-D and 1 mg/l BAP in the dark conditions. The compact granular organogenic callus formation (85% frequency) was obtained on MS medium supplemented with 2.5 mg/l 2,4-D and 1.5 mg/l BAP at light conditions. MS medium supplemented with 2 mg/l BAP, 1 mg/l Kinetin and 0.5 mg/l NAA promoted the highest frequency of shoot induction. The highest frequency of root formation was observed when shoots were grown on MS medium. The regenerated plants were successfully hardened in earthen pots after adequate acclimatization. The important advantage of this improved method is shortening of regeneration time by providing an efficient and rapid regeneration tool for obtaining more stable transformants from mature seeds of Indian tropical maize cultivar (HQPM-1).     

The Conserved Intronic Cleavage and Polyadenylation Site of CstF-77 Gene Imparts Control of 3′ End Processing Activity through Feedback Autoregulation and by U1 snRNP

The human gene encoding the cleavage/polyadenylation (C/P) factor CstF-77 contains 21 exons. However, intron 3 (In3) accounts for nearly half of the gene region, and contains a C/P site (pA) with medium strength, leading to short mRNA isoforms with no apparent protein products. This intron contains a weak 5′ splice site (5′SS), opposite to the general trend for large introns in the human genome. Importantly, the intron size and strengths of 5′SS and pA are all highly conserved across vertebrates, and perturbation of these parameters drastically alters intronic C/P. We found that the usage of In3 pA is responsive to the expression level of CstF-77 as well as several other C/P factors, indicating it attenuates the expression of CstF-77 via a negative feedback mechanism. Significantly, intronic C/P of CstF-77 pre-mRNA correlates with global 3′UTR length across cells and tissues. In addition, inhibition of U1 snRNP also leads to regulation of the usage of In3 pA, suggesting that the C/P activity in the cell can be cross-regulated by splicing, leading to coordination between these two processes. Importantly, perturbation of CstF-77 expression leads to widespread alternative cleavage and polyadenylation (APA) and disturbance of cell proliferation and differentiation. Thus, the conserved intronic pA of the CstF-77 gene may function as a sensor for cellular C/P and splicing activities, controlling the homeostasis of CstF-77 and C/P activity and impacting cell proliferation and differentiation.     

Molecular typing of Bordetella parapertussis isolates circulating in Pakistan

Although a whole-cell pertussis vaccine was introduced in Pakistan in 1980, little is known about the pertussis prevalence and circulating strains in Pakistan. The aim of this study was to analyze Bordetella parapertussis isolates circulating between 2005 and 2009 in Pakistan and to compare them with those found in other countries during different periods. A total of 59 (7.35%) B.?parapertussis isolates from 802 subjects (median age, 3?years) from Pakistan, with pertussis-like symptoms were investigated. We carried out genotyping and DNA microarray analyses on these isolates and compared them with some international isolates of B.?parapertussis. We found that the allele for pertactin (prn) found in strains studied from Pakistan was identical to the predominant type found in Europe. We showed that B.?parapertussis isolates circulating in Pakistan are part of the same pulsed-field gel electrophoresis group to those circulating in Finland during the period of 1982-2007. Finally, microarray analysis confirmed that the isolates collected in Pakistan, were quite similar to international strains. Overall, these results confirm that B.?parapertussis is extremely monomorphic. The high isolation rate of B.?parapertussis (7.35%) compared to Bordetella pertussis (0.5%) may suggest that the whole-cell vaccine used in Pakistan is effective against B.?pertussis (0.5% infections detected), but much less so against B.?parapertussis.     

Maximum likelihood analysis of mammalian p53 indicates the presence of positively selected sites and higher tumorigenic mutations in purifying sites

The tumor suppressor gene TP53 (p53) maintains genome stability. Mutation or loss of p53 is found in most cancers. Analysis of evolutionary constrains and p53 mutations reveal important sites for concomitant functional studies. In this study, phylogenetic analyses of the coding sequences of p53 from 26 mammals were carried out by applying a maximum likelihood method. The results display two branches under adaptive evolution in mammals. Moreover, each codon of p53 was analyzed by the PAML method for presence of positively selected sites. PAML identified several statistically significant amino acids that undergo positive selection. The data indicates that amino acids responsible for the core functions of p53 are highly conserved, while positively selected sites are predominantly located in the N- and C-terminus of p53. Further analysis of evolutionary pressure and mutations showed the occurrence of more frequent tumorigenic mutations in purifying sites of p53.