Evaluation of elevated alanine aminotransferase and hepatitis B virus DNA in healthy seronegative blood donors

Background: Serum alanine transaminase (ALT) has been used as a surrogate marker for detection of hepatitis B and C in blood donors in Pakistan since 1985. Since the introduction of more sensitive assays the value of ALT became questionable but it was still used with subsequent wastage of blood units with raised ALT. Finding: We conducted a study for a period of one year to evaluate the usefulness of ALT. During the study period, 25117 subjects donated blood. Eight hundred and seventy two donors (3.4%) were positive for one or more serological tests. ALT of all donors ranged from 0-1501 U/L (Mean±SD; 33.4±25.45U/L). The donors seronegative for all disease markers were 24245 (96.6%). Of these, 21164 (84.2%) donors had their ALT within reference range while 2874 (11.4%) and 207 (0.8%) of donors had minimal and markedly elevated results respectively. Six hundred and twenty one blood units (including red cells, platelets and plasma) were discarded based on elevated ALT results alone at a cost of $39,123. Two hundred seronegative blood donors with normal ALT, minimally and markedly elevated ALT levels, were selected randomly and evaluated for hepatitis B deoxynucleic acid by individual PCR. None of the donors was found to be reactive. Conclusion: This work did not support a positive association between hepatitis B virus nucleic acid and elevated ALT in healthy serologically negative blood donors

Improved shear strength prediction model of steel fiber reinforced concrete beams by adopting gene expression programming

In this study, an artificial intelligence tool called gene expression programming (GEP) has been successfully applied to develop an empirical model that can predict the shear strength of steel fiber reinforced concrete beams. The proposed genetic model incorporates all the influencing parameters such as the geometric properties of the beam, the concrete compressive strength, the shear span-to-depth ratio, and the mechanical and material properties of steel fiber. Existing empirical models ignore the tensile strength of steel fibers, which exercise a strong influence on the crack propagation of concrete matrix, thereby affecting the beam shear strength. To overcome this limitation, an improved and robust empirical model is proposed herein that incorporates the fiber tensile strength along with the other influencing factors. For this purpose, an extensive experimental database subjected to four-point loading is constructed comprising results of 488 tests drawn from the literature. The data are divided based on different shapes (hooked or straight fiber) and the tensile strength of steel fiber. The empirical model is developed using this experimental database and statistically compared with previously established empirical equations. This comparison indicates that the proposed model shows significant improvement in predicting the shear strength of steel fiber reinforced concrete beams, thus substantiating the important role of fiber tensile strength.National University of Science and Technolog

Posttransplant nephrocalcinosis is associated with poor renal allograft function: A single-center experience

Background: Nephrocalcinosis, characterized by intratubular and/ or parenchymal deposition of calcium phosphate and calcium oxalate crystals, is frequently seen in renal allograft biopsies; however, the clinical consequence of this histologic finding remains unknown. Kidney transplant recipients with good allograft function usually demonstrate improvement in biochemical parameters; however, persistent hyperparathyroidism remains prevalent in this population of patients. We identified renal allografts with nephrocalcinosis and evaluated the effects on renal allograft function and survival.Methods: We conducted a single-center, retrospective review of kidney allograft biopsies performed at our center from December 1, 2006 to November 30, 2012. Biopsies with nephrocalcinosis as the primary diagnosis were included in the final analysis. Biochemical parameters at the time of biopsy included serum creatinine, phosphate, calcium, intact parathyroid hormone (iPTH), 25-hydroxy vitamin D, and albumin. Serum creatinine was measured at 1, 3, 6, and 12 months after nephrocalcinosis was diagnosed. The use of calcimimetics, vitamin D analogs, active vitamin D, and bisphosphonates was also reviewed.Results: We identified 12 patients with nephrocalcinosis as the primary diagnosis on renal biopsy. The average age of these patients was 52.2 +/- 11.9 years, and the average time since transplantation was 2.3 +/- 2.7 years. The baseline serum creatinine was 1.37 +/- 0.4 mg/dL before the onset of acute kidney injury (AKI). Mean iPTH and 25-hydroxy vitamin D at the time of AKI were 495.66 -358.9 pg/mL and 19.9 +/- 13.3 ng/mL, respectively. Renal function deteriorated in all patients, and mean serum creatinine at 12-month follow up was 2.37 +/- 1.3 mg/dL (P = 0.028). One patient progressed to end-stage renal disease at the end of the study period.Conclusion: The histologic finding of nephrocalcinosis is associated with poor renal allograft function. Metabolic abnormalities including hyperparathyroidism persist in renal allograft recipients despite normal allograft function and may be associated with the development of nephrocalcinosis in renal transplant recipients

Population study of 1311 C/T polymorphism of Glucose 6 Phosphate Dehydrogenase gene in Pakistan – an analysis of 715 X-chromosomes

<p>Abstract</p> <p>Background</p> <p>Nucleotide 1311 polymorphism at exon 11 of G6PD gene is widely prevalent in various populations of the world. The aim of the study was to evaluate 1311 polymorphism in subjects carrying G6PD Mediterranean gene and in general population living in Pakistan.</p> <p>Results</p> <p>Patients already known to be G6PD deficient were tested for 563C-T (G6PD Mediterranean) and 1311 C-T mutation through RFLP based PCR and gene sequencing. A control group not known to be G6PD deficient was tested for 1311C/T only.</p> <p>C-T transition at nt 1311 was detected in 60/234 X-chromosomes with 563 C-T mutation (gene frequency of 0.26) while in 130 of normal 402 X-chromosomes (gene frequency of 0.32).</p> <p>Conclusion</p> <p>We conclude that 1311 T is a frequent polymorphism both in general populations and in subjects with G6PD Mediterranean gene in Pakistan. The prevalence is higher compared to most of the populations of the world. The present study will help in understanding genetic basis of G6PD deficiency in Pakistani population and in developing ancestral links of its various ethnic groups.</p

Role of special coagulation studies for preoperative screening of thrombotic complications in simultaneous pancreas-kidney transplantation

Background: Vascular thrombosis is a well-known complication after simultaneous pancreas-kidney (SPK) transplantation procedures. The role of preoperative special coagulation studies to screen patients at high risk for vascular thrombosis is unclear and not well studied

Gene Expression Programming for Estimating Shear Strength of RC Squat Wall

The flanged, barbell, and rectangular squat reinforced concrete (RC) walls are broadly used in low-rise commercial and highway under and overpasses. The shear strength of squat walls is the major design consideration because of their smaller aspect ratio. Most of the current design codes or available published literature provide separate sets of shear capacity equations for flanged, barbell, and rectangular walls. Also, a substantial scatter exists in the predicted shear capacity due to a large discrepancy in the test data. Thus, this study aims to develop a single gene expression programming (GEP) expression that can be used for predicting the shear strength of these three cross-sectional shapes based on a dataset of 646 experiments. A total of thirteen influencing parameters are identified to contrive this efficient empirical compared to several shear capacity equations. Owing to the larger database, the proposed model shows better performance based on the database analysis results and compared with 9 available empirical models

Hemoglobin E syndromes in Pakistani population

<p>Abstract</p> <p>Background</p> <p>Hemoglobin E is an important hemoglobin variant with a worldwide distribution. A number of hemoglobinopathies have been reported from Pakistan. However a comprehensive description of hemoglobin E syndromes for the country was never made. This study aimed to describe various hemoglobin E disorders based on hematological parameters and chromatography. The sub-aim was to characterize hemoglobin E at molecular level.</p> <p>Methods</p> <p>This was a hospital based study conducted prospectively for a period of one year extending from January 1 to December 31, 2008. EDTA blood samples were analyzed for completed blood counts and hemoglobin variants through automated hematology analyzer and Bio-Rad beta thalassaemia short program respectively. Six samples were randomly selected to characterize HbE at molecular level through RFLP-PCR utilizing <it>Mnl</it>I restriction enzyme.</p> <p>Results</p> <p>During the study period, 11403 chromatograms were analyzed and Hb E was detected in 41 (or 0.36%) samples. Different hemoglobin E syndromes identified were HbEA (n = 20 or 49%), HbE/β-thalassemia (n = 14 or 34%), HbEE (n = 6 or 15%) and HbE/HbS (n = 1 or 2%). Compound heterozygosity for HbE and beta thalassaemia was found to be the most severely affected phenotype. RFLP-PCR utilizing <it>Mnl</it>I successfully characterized HbE at molecular level in six randomly selected samples.</p> <p>Conclusions</p> <p>Various HbE phenotypes are prevalent in Pakistan with HbEA and HbE/β thalassaemia representing the most common syndromes. Chromatography cannot only successfully identify hemoglobin E but also assist in further characterization into its phenotype including compound heterozygosity. Definitive diagnosis of HbE can easily be achieved through RFLP-PCR.</p

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Experimental Study of Scour Hole Depth around Bridge Pile Using Efficient Cross-Section

Extensive numerical and analytical studies exist that focus on the scours around bridge piers with different cross-sections. However, studies addressing the scour around bridge piles are rather limited and not conclusive. Therefore, the most efficient cross-section reducing the local scour around a pile group is experimentally examined herein. Accordingly, comparative scouring of three different shapes, namely, circular, rectangular and lenticular, is investigated by installing a cohesion-less bedding material around scaled bridge piles immersed in clear water. It is also shown that the available pier scour predictive models grossly underestimate the depth of pile scour holes. For example, the pier predictive models underestimate the pile scours hole by more than 50% in the case of square and circular cross-sections. It also transpires from the experimental investigation that the scour hole depth around the square shape pile is significant, around the circular pile is moderate and around the lenticular pile is minimal

Evaluation of elevated alanine aminotransferase and hepatitis B virus DNA in healthy seronegative blood donors

Abstract Background Serum alanine transaminase (ALT) has been used as a surrogate marker for detection of hepatitis B and C in blood donors in Pakistan since 1985. Since the introduction of more sensitive assays the value of ALT became questionable but it was still used with subsequent wastage of blood units with raised ALT. Findings We conducted a study for a period of one year to evaluate the usefulness of ALT. During the study period, 25117 subjects donated blood. Eight hundred and seventy two donors (3.4%) were positive for one or more serological tests. ALT of all donors ranged from 0–1501 U/L (Mean ± SD; 33.4 ± 25.45U/L). The donors seronegative for all disease markers were 24245 (96.6%). Of these, 21164 (84.2%) donors had their ALT within reference range while 2874 (11.4%) and 207 (0.8%) of donors had minimal and markedly elevated results respectively. Six hundred and twenty one blood units (including red cells, platelets and plasma) were discarded based on elevated ALT results alone at a cost of $39,123. Two hundred seronegative blood donors with normal ALT, minimally and markedly elevated ALT levels, were selected randomly and evaluated for hepatitis B deoxynucleic acid by individual PCR. None of the donors was found to be reactive. Conclusion This work did not support a positive association between hepatitis B virus nucleic acid and elevated ALT in healthy serologically negative blood donors.</p