Preliminary insights on the mutational spectrum of BRCA1 and BRCA2 genes in Pakhtun ethnicity breast cancer patients from Khyber Pakhtunkhwa (KP), Pakistan.

Gene mutations are a source of genetic instability which fuels the progression of cancer. Mutations in BRCA1 and BRCA2 are considered as major drivers in the progression of breast cancer and their detection indispensable for devising therapeutic and management approaches. The current study aims to identify novel pathogenic and recurrent mutations in BRCA1 and BRCA2 in Pakhtun population from the Khyber Pakhtunkhwa. To determine the BRCA1 and BRCA2 pathogenic mutation prevalence in Pakhtun population from KP, whole exome sequencing of 19 patients along with 6 normal FFPE embedded blocks were performed. The pathogenicity of the mutations were determined and they were further correlated with different hormonal, sociogenetic and clinicopathological features. We obtained a total of 10 mutations (5 somatic and 5 germline) in BRCA1 while 27 mutations (24 somatic and 3 germline) for BRCA2. Five and seventeen pathogenic or deleterious mutations were identified in BRCA1 and BRCA2 respectively by examining the mutational spectrum through SIFT, PolyPhen-2 and Mutation Taster. Among the SNVs, BRCA1 p.P824L, BRCA2 p. P153Q, p.I180F, p.D559Y, p.G1529R, p.L1576F, p.E2229K were identified as mutations of the interaction sites as predicted by the deep algorithm based ISPRED-SEQ prediction tool. SAAFEQ-SEQ web-based algorithm was used to calculate the changes in free energy and effect of SNVs on protein stability. All SNVs were found to have a destabilizing effect on the protein. ConSurf database was used to determine the evolutionary conservation scores and nature of the mutated residues. Gromacs 4.5 was used for the molecular simulations. Ramachandran plots were generated using procheck server. STRING and GeneMania was used for prediction of the gene interactions. The highest number of mutations (BRCA1 7/10, 70 %) were on exon 9 and (BRCA2, 11/27; 40 %) were on exon 11. 40 % and 60 % of the BRCA2 mutations were associated Grade 2 and Grade 3 tumors respectively. The present study reveals unique BRCA1 and BRCA2 mutations in Pakhtun population. We further suggest sequencing of the large cohorts for further characterizing the pathogenic mutations.

Mutational Landscape and In-Silico Analysis of TP53, PIK3CA, and PTEN in Patients with Breast Cancer from Khyber Pakhtunkhwa.

Herein, we report the mutational spectrum of three breast cancer candidate genes (TP53, PIK3CA, and PTEN) using WES for identifying potential biomarkers. The WES data were thoroughly analyzed using SAMtools for variant calling and identification of the mutations. Various bioinformatic tools (SIFT, PolyPhen-2, Mutation Taster, ISPRED-SEQ, SAAFEQ-SEQ, ConSurf, PROCHECK etc.) were used to determine the pathogenicity and nature of the SNVs. Selected interaction site (IS) mutations were visualized in PyMOL after building 3D structures in Swiss-Model. Ramachandran plots were generated by using the PROCHECK server. The selected IS mutations were subjected to molecular dynamic simulation (MDS) studies using Gromacs 4.5. STRING and GeneMANIA were used for the prediction of gene-gene interactions and pathways. Our results revealed that the luminal A molecular subtype of the breast cancer was most common, whereas a high percentage of was Her2 negatives. Moreover, the somatic mutations were more common as compared to the germline mutations in TP53, PIK3CA, and PTEN. 20% of the identified mutations are reported for the first time from Khyber Pakhtunkhwa. In the enrolled cohort, 23 mutations were nonsynonymous SNVs. The frequency of mutations was the highest in PIK3CA, followed by TP53 and PTEN. A total of 13 mutations were found to be highly pathogenic. Four novel mutations were identified on PIK3CA and one each on PTEN and TP53. SAAFEQ-SEQ predicted the destabilizing effect for all mutations. ISPRED-SEQ predicted 9 IS mutations (6 on TP53 and 3 on PIK3CA), whereas no IS mutation was predicted on PTEN. The TP53 IS mutations were TP53R43H, TP53Y73X, TP53K93Q, TP53K93R, TP53D149E, and TP53Q199X; whereas for PIK3CA, the IS mutations were PIK3CAL156V, PIK3CAM610K, and PIK3CAH1047R. Analysis from the ConSurf Web server revealed five SNVs with a highly conserved status (conservation score 9) across TP53 and PTEN. TP53P33R was found predominant in the grade 3 tumors, whereas PTENp.C65S was distributed on ER+, ER-, PR+, PR-, Her2+, and Her2- patients. TP53p.P33R mutation was found to be recurring in the 14/19 (73.6%) patients and, therefore, can be considered as a potential biomarker. Finally, these mutations were studied in the context of their potential association with different hormonal and social factors.

Bandgap Engineering of Melon using Highly Reduced Graphene Oxide for Enhanced Photoelectrochemical Hydrogen Evolution.

The uncondensed form of polymeric carbon nitrides (PCN), generally known as melon, is a stacked 2D structure of poly(aminoimino)heptazine. Melon is used as a photocatalyst in solar energy conversion applications, but suffers from poor photoconversion efficiency due to weak optical absorption in the visible spectrum, high activation energy, and inefficient separation of photoexcited charge carriers. Experimental and theoretical studies are reported to engineer the bandgap of melon with highly reduced graphene oxide (HRG). Three HRG@melon nanocomposites with different HRG:melon ratios (0.5%, 1%, and 2%) are prepared. The 1% HRG@melon nanocomposite shows higher photocurrent density (71 µA cm-2 ) than melon (24 µA cm-2 ) in alkaline conditions. The addition of a hole scavenger further increases the photocurrent density to 630 µA cm-2 relative to the reversible hydrogen electrode (RHE). These experimental results are validated by calculations using density functional theory (DFT), which revealed that HRG results in a significant charge redistribution and an improved photocatalytic hydrogen evolution reaction (HER).

Controlling basal plane sulfur vacancy in water splitting MoSx/NiF electrocatalysts through electric-field-assisted pulsed laser ablation.

Eco-friendly, efficient, and durable electrocatalysts from earth-abundant materials are crucial for water splitting through hydrogen and oxygen generation. However, available methods to fabricate electrocatalysts are either hazardous and time-consuming or require expensive equipment, hindering the large-scale, eco-friendly production of artificial fuels. Here, we present a rapid, single-step method for producing MoSx/NiF electrocatalysts with controlled sulfur-vacancies via electric-field-assisted pulsed laser ablation (EF-PLA) in liquid and in-situ deposition on nickel foam, enabling efficient water splitting. Electric-field parameters efficiently control S-vacancy active sites in electrocatalysts. Higher electric fields yield a MoSx/NiF electrocatalyst with a larger density of S-vacancy sites, suited for HER due to lower Gibbs free energy for H∗ adsorption, while lower electric fields produce an electrocatalyst with lower S-vacancy sites, better suited for OER, as shown by both experimental and theoretical results. The present work opens a horizon in designing high-efficiency catalysts, for a wide range of chemical reactions.

Structure-based virtual screening and molecular docking of drugs against the SARS-CoV-2 spike protein-ACE2 receptor complex.

The agent responsible for the COVID-19 pandemic was the newly discovered coronavirus SARS-CoV-2. A trimeric spike protein on the SARS-CoV-2 virion binds to the ACE2 receptor on host cells. In this study we performed a structure-based virtual screening and molecular docking of existing drugs against a high-resolution structure of the SARS-CoV-2 spike protein-ACE2 receptor complex. The 2.5-Å crystal structure of the C-terminal domain of the SARS-CoV-2 spike protein (residues 319-541) in complex with human ACE2 (SARS-CoV-2-S-CTD/hACE2) (PDB ID: 6LZG) was used as the target for screening 4,374 FDA-approved drugs from the ZINC15 database using PyRx software. Molecular docking was performed using BIOVIA Discovery Studio Visualizer. The top twenty highest affinity drugs had binding energies of -7.0 to -8.8 kcal/mol. The highest affinity drug was the selective vasopressin V2-receptor antagonist Tolvaptan, for which molecular docking identified drug-amino acid residue interactions with ACE2. Other drugs displaying binding energies better than -8.0 kcal/mol were Nizoral, Amaryl, Accolate, Sorafenib, Glipizide and Azelastine. The predicted interactions of these highest affinity drugs with residues in ACE2 were at positions that could disrupt the spike protein-ACE2 complex, so these drugs have the potential to be repurposed as inhibitors of the SARS-CoV-2 virus.

Identification of Potential HCV Inhibitors Based on the Interaction of Epigallocatechin-3-Gallate with Viral Envelope Proteins.

Hepatitis C is affecting millions of people around the globe annually, which leads to death in very high numbers. After many years of research, hepatitis C virus (HCV) remains a serious threat to the human population and needs proper management. The in silico approach in the drug discovery process is an efficient method in identifying inhibitors for various diseases. In our study, the interaction between Epigallocatechin-3-gallate, a component of green tea, and envelope glycoprotein E2 of HCV is evaluated. Epigallocatechin-3-gallate is the most promising polyphenol approved through cell culture analysis that can inhibit the entry of HCV. Therefore, various in silico techniques have been employed to find out other potential inhibitors that can behave as EGCG. Thus, the homology modelling of E2 protein was performed. The potential lead molecules were predicted using ligand-based as well as structure-based virtual screening methods. The compounds obtained were then screened through PyRx. The drugs obtained were ranked based on their binding affinities. Furthermore, the docking of the topmost drugs was performed by AutoDock Vina, while its 2D interactions were plotted in LigPlot+. The lead compound mms02387687 (2-[[5-[(4-ethylphenoxy) methyl]-4-prop-2-enyl-1,2,4-triazol-3-yl] sulfanyl]-N-[3(trifluoromethyl) phenyl] acetamide) was ranked on top, and we believe it can serve as a drug against HCV in the future, owing to experimental validation.

A structure-based virtual screening and molecular docking by using potent inhibitors against nucleoprotein of Crimean-Congo hemorrhagic fever virus.

BACKGROUND & OBJECTIVES: Crimean-Congo Hemorrhagic Fever Virus (CCHFV) is a vector borne pathogen, well-known for causing endemic hemorrhagic fever in Asia, Europe and Africa. There is no specific drug or vaccine available against CCHFV. The recent upsurge of Crimean-Congo Hemorrhagic Fever around the globe has made it a major health issue and this demands investigation for specific inhibitors to viral proteins. The objective of this study was to assess inhibitors that may have the potential to dock CCHFV nucleoprotein which plays an important role in viral assembly. METHODS: We performed structure-based virtual screening and molecular docking by using potent inhibitors against nucleoprotein of CCHFV. Screening was performed by a webserver, MtiOpenScreen which gave 1000 drug-like molecules from PubChem. PyRx Autodock vina was utilized to dock the protein. The docking poses were observed for interaction analysis by LigPlot+. This study provided ten potential candidates capable of binding to the active site of NP of CCHFV. The selected hits were then subjected to toxicity prediction by ProTox-II. RESULTS: Four hits were identified that specifically dock nucleoprotein at the presumed binding site. Furthermore, these compounds have less binding energy i.e., 9.7 kcal/mol, 9.8 kcal/mol and 10.4 kcal/mol and with equal toxicity measures when compared to an FDA approved drug. INTERPRETATION & CONCLUSION: This study illustrates that virtual screening is an efficient in silico approach to identify target-specific inhibitors. Researchers in this area who investigate drugs or synthesize agents against CCHFV with better efficacy could utilize reported inhibitors rather than trying random compounds ambivalently.

Compositional Engineering Study of Lead-Free Hybrid Perovskites for Solar Cell Applications.

Hybrid organic-inorganic perovskite solar cells (HOIPs), especially CH3NH3PbI3 (MAPbI3), have received tremendous attention due to their excellent power conversion efficiency (25.2%). However, two fundamental hurdles, long-term stability and lead (Pb) toxicity, prevent HOIPs from practical applications in the solar industry. To overcome these issues, compositional engineering has been used to modify cations at A- and B-sites and anions at the X-site in the general form ABX3. In this work, we used the density functional theory (DFT) to incorporate Rb, Cs, and FA at the A-site to minimize the volatile nature of MA, while the highly stable Ca2+ and Sr2+ were mixed with the less stable Ge2+ and Sn2+ at the B-site to obtain a Pb-free perovskite. To further enhance the stability, we mixed the X-site anions (I/Br). Through this approach, we introduced 20 new perovskite species to the lead-free perovskite family and 7 to the lead-containing perovskite family. The molecular dynamic (MD) simulations, enthalpy formation, and tolerance and octahedral factor study confirm that all of the perovskite alloys we introduced here are as stable as pristine MAPbI3. All Pb-free perovskites have suitable and direct band gaps (1.42-1.77 eV) at the Γ-point, which are highly desirable for solar cell applications. Most of our Pb-free perovskites have smaller effective masses and exciton binding energies. Finally, we show that the introduced perovskites have high absorption coefficients (105 cm-1) and strong absorption efficiencies (above 90%) in a wide spectral range (300-1200 nm), reinforcing their significant potential applications. This study provides a new way of searching for stable lead-free perovskites for sustainable and green energy applications.

In silico identification and structure function analysis of a putative coclaurine N-methyltransferase from Aristolochia fimbriata.

In this study we isolated and performed in silico analysis of a putative coclaurine N-methyltransferase (CNMT) from the basal angiosperm Aristolochia fimbriata. The Aristolochiaceae plant family produces alkaloids similar to the Papavaraceae family, and CNMTs are central enzymes in biosynthesis pathways producing compounds of ethnopharmacological interest. We used bioinformatics and computational tools to predict a three-dimensional homology model and to investigate the putative function of the protein and its mechanism for methylation. The putative CNMT is a unique (S)-adenosyl-L-methionine (SAM)-dependent N-methyltransferase, catalyzing transfer of a methyl group from SAM to the amino group of coclaurine. The model revealed a mixed α/ß structure comprising seven twisted ß-strands surrounded by twelve α-helices. Sequence comparisons and the model indicate an N-terminal catalytic Core domain and a C-terminal domain, of which the latter forms a pocket for coclaurine. An additional binding pocket for SAM is connected to the coclaurine binding pocket by a small opening. CNMT activity is proposed to follow an SN2-type mechanism as observed for a similarly conformed enzyme. Residues predicted for the methyl transfer reaction are Tyr79 and Glu96, which are conserved in the sequence from A. fimbriata and in homologous N-methyltransferases. The isolated CNMT is the first to be investigated from any basal angiosperm.

Identification of potential inhibitors of Zika virus NS5 RNA-dependent RNA polymerase through virtual screening and molecular dynamic simulations.

Zika virus (ZIKV) is one of the mosquito borne flavivirus with several outbreaks in past few years in tropical and subtropical regions. The non-structural proteins of flaviviruses are suitable active targets for inhibitory drugs due to their role in pathogenicity. In ZIKV, the non-structural protein 5 (NS5) RNA-Dependent RNA polymerase replicates its genome. Here we have performed virtual screening to identify suitable ligands that can potentially halt the ZIKV NS5 RNA dependent RNA polymerase (RdRp). During this process, we searched and screened a library of ligands against ZIKV NS5 RdRp. The selected ligands with significant binding energy and ligand-receptor interactions were further processed. Among the selected docked conformations, top five was further optimized at atomic level using molecular dynamic simulations followed by binding free energy calculations. The interactions of ligands with the target structure of ZIKV RdRp revealed that they form strong bonds within the active sites of the receptor molecule. The efficacy of these drugs against ZIKV can be further analyzed through in-vitro and in-vivo studies.

To Evaluate and Compare Changes in Baseline Strength of Hairs after Treating them with Deionized Water and Hard Water and its Role in Hair Breakage.

BACKGROUND AND AIM: Interaction of hair with water is common. This study was conducted to compare changes in baseline strength of hair after treating it with hard water and deionized water. MATERIAL AND METHODS: Hardness level of water samples collected from 10 districts of KP, Pakistan was determined, and that with maximum hardness was considered our sample hard water. Hair samples of 70 male individuals, from district with minimum hardness levels, were collected. Each hair sample was divided into three equal parts, and three groups of hair were established, each group containing 70 hairs. Group A was considered control. Group B was treated with deionized water and Group C was treated with hard water. Tensile strength of all three groups was measured using the universal testing machine and compared using paired t-test. RESULTS: The mean age of all 70 participants were 23.87 ± 3. The mean values of tensile strength for hairs of Groups A, B, and C were 255.49, 254.84, and 234.16 with a standard deviation of 57.55, 58.74, and 56.25, respectively. Results were significant in case of hard water (P = 0.001) as compared to deionized water (P = 0.609). CONCLUSION: Hard water decreases strength of hair and thus increases breakage.

Effect of percutaneous transvenous mitral commissurotomy on brain natriuretic peptide in mitral stenosis in tertiary care hospitals of Peshawar.

The current study was planned to determine the effect of percutaneous transvenous mitral commissurotomy (PTMC) on brain natriuretic peptide (BNP) levels in mitral stenosis patients. It was conducted at the Postgraduate Medical Institute, Lady Reading Hospital, Peshawar, and Rehman Medical Institute Laboratory, Peshawar, Pakistan, from December 2013 to June 2014. Of the 100 patients, 63(63%) were females. The patients' age ranged from 14 to 58 years. Patients diagnosed with isolated mitral valve stenosis or with grade 1 or with grade 2 mitral regurgitation were randomly selected. BNP values before and after 24 hours of PTMC were calculated. The statistical analysis of the echocardiographic variables and BNP levels showed an increase in mitral valve area, drop in pulmonary artery systolic pressure, left atrium diameter and reduction in BNP levels (p<0,05 each) after PTMC that provides a concrete evidence for a successful PTMC procedure.

Whole-exome sequencing analysis reveals co-segregation of a COL20A1 missense mutation in a Pakistani family with striate palmoplantar keratoderma.

Palmoplantar keratoderma (PPK) is a rare group of excessive skin disorder characterized by thickness over the palms and soles. The striate palmoplantar keratoderma (PPKS) is a form in which hyperkeratotic lesions are restricted to the pressure regions extending longitudinally in the length of each finger to the palm. Dominantly inherited mutations in genes including desmoglein 1, desmoplakin and keratin 1 have been suggested as genetic causes of PPKS. In this study, we investigated a three-generation Pakistani family segregating PPKS phenotype in autosomal dominant fashion to identify genetic cause in this family. We have performed whole-exome and Sanger sequencing followed by in silico bioinformatics analysis to pinpoint candidate mutation associated with PPK. Revealed a novel heterozygous mutation (NM_020882.2, COL20A1 c. 392C > G; p.Ser131Cys) in the loop region close to fibronectin type III-1 domain of the c ollagen 20 α1. This variant was not found in our in-house 219 ethnically matched Pakistani unaffected controls and showed minor allele frequency of 3.4 × 10-5 in Exome Aggregation Consortium database containing exome data of 59,464 worldwide individuals. It was assigned as "pathogenic" by in silico prediction tools. Previously, association of mutation in the COL14A1, one of the paralogous gene of COL20A1, with PPK was reported in the study with a Chinese family. Our study proposes COL20A1 gene as another potential candidate gene for PPKS which expand the spectrum of collagen proteins in the pathogenicity of PPK.

Laparoscopic versus open appendectomy in children: a randomized controlled trial from a developing country.

BACKGROUND: Acute appendicitis is a common surgical emergency. This study was conducted to compare the outcome in terms of duration of surgery, length of hospital stay, and wound infection rate following laparoscopic versus open appendectomy in children with acute appendicitis. METHODS: A prospective randomized controlled trial was conducted. Patients with the diagnosis of acute appendicitis were randomly assigned to Group A: Laparoscopic appendectomy (LA) and Group B: Open appendectomy (OA). Age and sex of patients, signs, and symptoms were noted. Duration of surgery, length of hospital stay (LOS), and postoperative wound infection were recorded. RESULTS: A total of 126 patients were operated, with 63 in each group. Mean age of the patients was 9.7±2.1years in LA group and 9.8±2.3years in OA group. In LA group, inflamed appendix was found in 68% patients, perforated in 17%, gangrenous in 9%, and suppurative in 5%. In OA group, inflamed appendix was found in 60% patients, perforated in 22%, gangrenous in 5%, and suppurative in 13%. The mean duration of operation was 56±24min in LA group and 39±8min in OA group (p<0.0001 in favor of OA group). The mean length of hospital stay was 34±13h in LA group and 40±11h in OA group (p=0.01 in favor of LA group). The results showed no significant association of wound infection between the two groups (p=0.31). CONCLUSION: There was no difference in terms of LOS and rate of wound infection among the groups. However, the laparoscopic procedure was technically demanding. LEVEL OF EVIDENCE: Level I Randomized Controlled Trial.

Effect of topical application of hard water in weakening of hair in men.

Background: Hard water is thought to play a key role in weakening of hair (not Hair Loss) and breakage especially when travelling is involved. In our community, commonly men do the travelling and complain more about hair problem which is why only young male individuals were included in this study. Materials and Methods: Water samples from different districts of KPK, Pakistan, were collected and their hardness values were estimated to find the water sample of maximum and minimum water hardness in order to know the maximum hardness hair would encounter in KPK, Pakistan. Samples from district Kohat had maximum hardness whereas minimum hardness was estimated in samples of district Peshawar. Water from district Kohat was considered as our sample water for the experimental group of hair. Hair samples were collected from 76 male individuals of district Peshawar, the area with least water hardness among the samples collected. Each hair sample was divided into two halves. One half was considered as experimental group and the other was considered as control group. The experimental group was treated with hard water of district Kohat for 10 minutes on alternate days, for 3 months. In a very similar way the control group was treated with de-ionized water. Tensile strength in term of "Stress" of both the experimental and control groups were measured using the universal testing machine and compared using paired t-test. Results and Conclusions: The standard deviations (SD) for hair treated with hard water and distilled water was 62.05 and 58.13 respectively and the mean values were 238.49 and 255.36 respectively. The results showed that the tensile strength of hair was significantly (p=0.001) reduced in hair treated with hard water as compared to hair treated with de-ionized water.

Adipokine Serum visfatin level in pregnancy induced hypertension and uncomplicated pregnancy.

BACKGROUND AND OBJECTIVES: Hypertensive disorder in pregnancy is the significant disease that badly affects the maternal and fetal prognosis and lead to higher mortality and morbidity in the prenatal period. Visfatin, potentially a new adipokine has emerged having high contribution in pathogenesis of pre-eclampsia. The objective of the study was to find the level of Visfatin in pregnancy induced hypertension and normal pregnant women. METHODS: This study was carried out in tertiary care hospitals, Peshawar from March-October 2014. A total of 234 pregnant women (gestational age >20 weeks) were included in the study with distribution as Preeclampsia (PE=86), Eclampsia (E=74) and control (N=74). Blood was taken for measuring Visfatin level by Enzyme Linked Immunosorbent Assay (ELISA) technique. SPSS version 19 was used for statistical analysis. Student's t test was performed to evaluate the mean differences in patients and control. RESULTS: Serum level of visfatin was significantly higher in pregnancy induced hypertension when compared with control (P value<0.001).: Comparisons of mean value of visfatin with age group of 21-40 years, body mass index (BMI), primary parous and parity 2-4, gestational age of >36 weeks and both systolic and diastolic blood pressure were highly significant in pregnancy induced hypertension when compared with control (p value<0.001). CONCLUSION: Pregnancy induced hypertensive women showed increased level of serum Visfatin than normal pregnant women.

Quantification of Heavy Metals in Mining Affected Soil and Their Bioaccumulation in Native Plant Species.

Several anthropogenic and natural sources are considered as the primary sources of toxic metals in the environment. The current study investigates the level of heavy metals contamination in the flora associated with serpentine soil along the Mafic and Ultramafic rocks northern-Pakistan. Soil and wild native plant species were collected from chromites mining affected areas and analyzed for heavy metals (Cr, Ni, Fe, Mn, Co, Cu and Zn) using atomic absorption spectrometer (AAS-PEA-700). The heavy metal concentrations were significantly (p < 0.01) higher in mine affected soil as compared to reference soil, however Cr and Ni exceeded maximum allowable limit (250 and 60 mg kg(-1), respectively) set by SEPA for soil. Inter-metal correlations between soil, roots and shoots showed that the sources of contamination of heavy metals were mainly associated with chromites mining. All the plant species accumulated significantly higher concentrations of heavy metals as compared to reference plant. The open dumping of mine wastes can create serious problems (food crops and drinking water contamination with heavy metals) for local community of the study area. The native wild plant species (Nepeta cataria, Impatiens bicolor royle, Tegetis minuta) growing on mining affected sites may be used for soil reclamation contaminated with heavy metals.

Analysis of oxygen affinity in aquatic amphibian; homology modelling of the major haemoglobin component HbA1 from the African clawed frog (Xenopus laevis, Anura).

The homology model of major haemoglobin component HbA1 of the African Clawed Frog was predicted using the pigeon (Columba livia) haemoglobin as a template. The model was built with the help of MODELLER9v8. The models were evaluated with ProSA and PROCHECK. In X. laevis Gln38α is unable to form a hydrogen bond with ß97His or ß99Asp, which is responsible for the increase in oxygen affinity of the Xenopus HbA1. The hydrogen bond between α34Thr and ß124Pro, which stabilises the deoxy state of the haemoglobin, was absent in X. laevis. Hence it is predicted that the HbA1 component of X. laevis has higher oxygen affinity.

Structural and functional features of Streptolysin O.

Streptolysin O, a 63 kDa exotoxin coded by slo gene, is a well-characterised thiol-activated cytolysin, which damages cholesterol-containing membranes resulting in disruption and lysis of the target cell. On the basis of homology model and secondary structure analysis, the toxin has four domains of which domain 4 is of particular importance and is directly linked to domain 2 by a glycine linker and remained consistent in initial membrane recognition. Domain 4 reduces the hydrophobic ratio when compared with its template, which would affect the activity of the toxin at low pH.

Antioxidants. Do they have a place in the prevention or therapy of acute kidney injury?

Over the past several years, advances in our understanding of the pathogenesis of acute kidney injury (AKI) have demonstrated the role of oxidant stress and reactive oxygen metabolites (ROM) in the development of AKI in a variety of clinical settings. This review serves to define the pathways that lead to the generation of ROM following a variety of insults, as well as to review the current literature concerning the role of antioxidant therapy in the prevention and treatment of AKI in several clinical settings. Investigators have explored the potential therapeutic role of anti-oxidants in both experimental animal models and human studies of AKI in several clinical settings, including cardiac and aortic occlusive surgeries, sepsis, drug nephrotoxicity (cisplatin and gentamicin), as well as rhabdomyolysis. While the experimental animal studies have generally been more successful, taken together this literature supports the hypothesis that oxidant stress-induced production of ROM plays a major role in the pathogenesis of many forms of AKI, and continues to suggest the potential utility of antioxidant therapy in human AKI. Ongoing trials in concert with improved diagnostic techniques will hopefully lead to improved outcomes in the setting of AKI through the prophylactic or early therapeutic use of antioxidant therapy.