Evaluation of Status of Cadmium, Lead, and Nickel Levels in Biological Samples of Normal and Night Blindness Children of Age Groups 3–7 and 8–12 Years

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood trace metals toxicity, which is the most common problem found in underdeveloped countries. This study was designed to compare the levels of cadmium (Cd), lead (Pb), and nickel (Ni) in scalp hair, blood, and urine of night blindness children age ranged 3–7 and 8–12 years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of Cd, Pb, and Ni in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The digests of all biological samples were analyzed for Cd, Pb, and Ni by electrothermal atomic absorption spectrometry. The results indicated significantly higher levels of Cd, Pb, and Ni in the biological samples (blood, scalp hair, and urine) of male and female night blindness children, compared with control subjects of both genders. These data present guidance to clinicians and other professional investigating toxicity of trace metals in biological samples of night blindness children.     

Evaluation of Status of Zinc, Copper, and Iron Levels in Biological Samples of Normal Children and Children with Night Blindness with Age Groups of 3–7 and 8–12 Years

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence hair composition. This study was designed to compare the levels of zinc (Zn), copper (Cu), and iron (Fe) in scalp hair, blood, and urine of both genders of children with night blindness with age range of 3–7 and 8–12 years, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of zinc, copper, and iron in biological samples of children with night blindness. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The digests of all biological samples were analyzed for Cu, Fe, and Zn by flame atomic absorption spectrometry using an air/acetylene flame. The results indicated significantly lower levels of Fe, Cu, and Zn in the biological samples (blood and scalp hair) of male and female children with night blindness, compared with control subjects of both genders. These data present guidance to clinicians and other professionals investigating the deficiency of essential trace metals in biological samples (scalp hair and blood) of children with night blindness.     

Correlation Between Arsenic Concentration in Fish and Human Scalp Hair of People Living in Arsenic-Contaminated and Noncontaminated Areas of Pakistan

The effects of arsenic (As) toxicity due to frequent consumption of arsenic-contaminated fish was estimated by the analysis of scalp hair of adult males, living near arsenic-contaminated area of Pakistan. For comparison purposes, scalp hair samples were also collected from the inhabitants of Hyderabad city consuming fish species with low levels of As, collected from Indus River. Concentration of As in scalp hair samples was analyzed by using hydride generation atomic absorption spectrometry (HG AAS), after microwave-assisted acid digestion. The accuracy of the As measurement was tested simultaneously analyzing certified reference material. The concentration of As in muscle tissues of fish species were found in the range of 2.11 to 14.1?μg/g and 1.92 to 12.2?μg/g, collected from arsenic-contaminated and noncontaminated areas, respectively. Exposed subjects had significantly elevated levels of As in scalp hair samples (0.72-4.94?μg/g) as compared with referent subjects (0.21-1.484?μg/g; p?相似文献   

Molecular docking analysis of new generation cephalosporins interactions with recently known SHV-variants

Extended-spectrum-β-lactamases (ESBLs), constitutes the growing class of betalactamses, these are enzymes produced by bacteria which impart resistance against advanced-generation-cephalosporins. SHV enzymes are among the most prevalent ESBLs. The mode of molecular interactions of recent SHV-variants to advanced generation cephalosporins has not been reported yet. This is the first time we are reporting the insilico study of these recent variants with new generation cephaosporins. Homology models for SHV-105, SHV-95, SHV-89, SHV-61 and SHV-48 were generated using MODELLER9v3. New generation Cephalosporins were selected to target the active site amino acid residues of these modeled SHV enzymes for predicting comparative efficacies of these inhibitors against the said enzymes on the basis of interaction energies of docking. The docked complexes were analyzed by using DISCOVERY STUDIO 2.5. In this study A237, S70, K234, R275, N132, R244 and S130 were found crucial to the correct positioning of drugs within the binding site of SHV enzymes in 11, 6, 6, 6, 5, 5 and 5 instances, respectively. On the basis of interaction energy and Ki calculations cefatoxime emerged as the most efficient among the other advanced cephalosporins against all the studied SHV variants, excluding SHV-48 where ceftazidime was found to be most effective drug. Furthermore, this study identified amino acid residues crucial to 'SHV-Cephalosporins' interactions and this information will be useful in designing effective and versatile drug candidates.     

Phenotypic plasticity and effects of selection on cell division symmetry in Escherichia coli

Aging has been demonstrated in unicellular organisms and is presumably due to asymmetric distribution of damaged proteins and other components during cell division. Whether the asymmetry-induced aging is inevitable or an adaptive and adaptable response is debated. Although asymmetric division leads to aging and death of some cells, it increases the effective growth rate of the population as shown by theoretical and empirical studies. Mathematical models predict on the other hand, that if the cells divide symmetrically, cellular aging may be delayed or absent, growth rate will be reduced but growth yield will increase at optimum repair rates. Therefore in nutritionally dilute (oligotrophic) environments, where growth yield may be more critical for survival, symmetric division may get selected. These predictions have not been empirically tested so far. We report here that Escherichia coli grown in oligotrophic environments had greater morphological and functional symmetry in cell division. Both phenotypic plasticity and genetic selection appeared to shape cell division time asymmetry but plasticity was lost on prolonged selection. Lineages selected on high nutrient concentration showed greater frequency of presumably old or dead cells. Further, there was a negative correlation between cell division time asymmetry and growth yield but there was no significant correlation between asymmetry and growth rate. The results suggest that cellular aging driven by asymmetric division may not be hardwired but shows substantial plasticity as well as evolvability in response to the nutritional environment.     

The formation of a potential spring in the ribosome

Time-dependent chemical modification and cleavage results have provided intriguing insights into structural changes that occur in the distal loop of helix 11 in 16S ribosomal RNA (rRNA). Located distant from the decoding region, between proteins S17 and S20, the results of this study suggest that this region of rRNA may act as a buffer or a spring between these two proteins during protein biosynthesis. During the assembly process, protein S17 apparently produces the major structural deformations in this region, causing it to be folded in a spring-like structure. Base C264 in this region shows erratic behavior during assembly and also shows time-dependent enhancement when elongation factor G with GTP is added to 70S ribosomes. Evidence is presented to suggest that this region of rRNA may be used to allow relative motion to occur between proteins S17 and S20 during translocation.     

Determination of Copper and Iron in Biological Samples of Viral Hepatitis (A–E) Female Patients

There is accumulative evidence that the metabolism of iron and copper is altered in viral hepatic diseases, and these nutrients might have specific roles in their pathogenesis and progress. The aim of present study was to compare the level of copper (Cu) and iron (Fe) in biological samples (serum, urine, and scalp hair) of female patients suffering from different viral hepatitis (A, B, C, D, and E; n?=?253) of age range 31–45 years. For comparative study, 95 healthy females of the same age group residing in the same city were selected. The elements in the biological samples were analyzed by flame atomic absorption spectrophotometry, prior to microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with those values obtained by conventional wet acid digestion method on same CRMs. The results of this study showed that the mean values of Cu and Fe were higher in sera and scalp hair samples of hepatitis patients than age-matched control subjects, while the difference was significant (p?<?0.001), in the cases of viral hepatitis B and viral hepatitis C as compared to viral hepatitis A, D, and E. The urinary levels of these elements were found higher in the hepatitis patients than in the age-matched healthy controls (p?<?0.05). These results are consistent with literature-reported data, confirming that hepatic iron and copper overload can directly cause lipid peroxidation and eventually hepatic damage.     

Prevalence of autoantibodies against 3-DG-glycated H2A protein in type 2 diabetes

Advanced glycation end-products (AGEs) have been found to be critically involved in initiation or progression of diabetes secondary complications (nephropathy, retinopathy, neuropathy, and angiopathy). Various hyper-glycating carbonyl compounds such as 3-deoxyglucosone (3-DG) are produced in pathophysiological conditions that form AGEs in high quantity both in vivo and in vitro. In the first stage of this study, we glycated histone H2A protein by 3-DG, and the results showed the formation of various intermediates and AGEs as well as structural changes in the protein. In the second stage, we studied the immunogenicity of native and 3-DG-glycated H2A protein in female rabbits. The modified H2A was highly immunogenic, eliciting high titer immunogen-specific antibodies, while the unmodified form was almost nonimmunogenic. Antibodies against standard carboxymethyllysine (CML) and pentosidine were detected in the immunized female rabbits, which demonstrates the immunogenic nature of AGEs (CML and pentosidine) as well. The results show both structural perturbation and AGEs have the capacity of triggering the immune system due to the generation of neoepitopes that render the molecule immunogenic. This study shows the presence of autoantibodies against 3-DG-modified H2A, CML, and pentosidine in the sera of type 2 diabetes patients having secondary complications. Autoantibodies against damaged H2A and AGEs may be significant in the assessment of initiation/progression of secondary complications in type 2 diabetes mellitus patients or may be used as a marker for early detection of secondary complications in diabetes.     

Chlorine‐Enabled Electron Doping in Solution‐Synthesized SnSe Thermoelectric Nanomaterials

An aqueous solution method is developed for the facile synthesis of Cl‐containing SnSe nanoparticles in 10 g quantities per batch. The particle size and Cl concentration of the nanoparticles can be efficiently tuned as a function of reaction duration. Hot pressing produces n‐type Cl‐doped SnSe nanostructured compacts with thermoelectric power factors optimized via control of Cl dopant concentration. This approach, combining an energy‐efficient solution synthesis with hot pressing, provides a simple, rapid, and low‐cost route to high performance n‐type SnSe thermoelectric materials.