Frequent Transient Hepatitis C viremia without Seroconversion among Healthcare Workers in Cairo,Egypt

Backgrounds

With 10% of the general population aged 15–59 years chronically infected with hepatitis C virus (HCV), Egypt is the country with the highest HCV prevalence worldwide. Healthcare workers (HCWs) are therefore at particularly high risk of HCV infection. Our aim was to study HCV infection risk after occupational blood exposure among HCWs in Cairo.

Methodology/Principal Findings

The study was conducted in 2008–2010 at Ain Shams University Hospital, Cairo. HCWs reporting an occupational blood exposure at screening, having neither anti-HCV antibodies (anti-HCV) nor HCV RNA, and exposed to a HCV RNA positive patient, were enrolled in a 6-month prospective cohort with follow-up visits at weeks 2, 4, 8, 12 and 24. During follow-up, anti-HCV, HCV RNA and ALT were tested. Among 597 HCWs who reported a blood exposure, anti-HCV prevalence at screening was 7.2%, not different from that of the general population of Cairo after age-standardization (11.6% and 10.4% respectively, p = 0.62). The proportion of HCV viremia among index patients was 37%. Of 73 HCWs exposed to HCV RNA from index patients, nine (12.3%; 95%CI, 5.8–22.1%) presented transient viremia, the majority of which occurred within the first two weeks after exposure. None of the workers presented seroconversion or elevation of ALT.

Conclusions/Significance

HCWs of a general University hospital in Cairo were exposed to a highly viremic patient population. They experienced frequent occupational blood exposures, particularly in early stages of training. These exposures resulted in transient viremic episodes without established infection. These findings call for further investigation of potential immune protection against HCV persistence in this high risk group.     

Enhanced production of bioethanol from waste of beer fermentation broth at high temperature through consecutive batch strategy by simultaneous saccharification and fermentation

Malt hydrolyzing enzymes and yeast glycolytic and fermentation enzymes in the waste from beer fermentation broth (WBFB) were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). A new ‘one-pot consecutive batch strategy’ was developed for efficient bio-ethanol production by simultaneous saccharification and fermentation (SSF) using WBFB without additional enzymes, microbial cells, or carbohydrates. Bio-ethanol production was conducted in batches using WBFB supernatant in the first phase at 25–67 °C and 50 rpm, followed by the addition of 3% WBFB solid residue to the existing culture broth in the second phase at 67 °C. The ethanol production increased from 50 to 102.5 g/L when bare supernatant was used in the first phase, and then to 219 g ethanol/L in the second phase. The amount of ethanol obtained using this strategy was almost equal to that obtained using the original WBFB containing 25% solid residue at 33 °C, and more than double that obtained when bare supernatant was used. Microscopic and gel electrophoresis studies revealed yeast cell wall degradation and secretion of cellular material into the surrounding medium. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) supported the existence of enzymes in WBFB involved in bioethanol production at elevated temperatures. The results of this study will provide insight for the development of new strategies for biofuel production.     

Improved pretreatment of lignocellulosic biomass using enzymatically-generated peracetic acid

Release of sugars from lignocellulosic biomass is inefficient because lignin, an aromatic polymer, blocks access of enzymes to the sugar polymers. Pretreatments remove lignin and disrupt its structure, thereby enhancing sugar release. In previous work, enzymatically generated peracetic acid was used to pretreat aspen wood. This pretreatment removed 45% of the lignin and the subsequent saccharification released 97% of the sugars remaining after pretreatment. In this paper, the amount of enzyme needed is reduced tenfold using first, an improved enzyme variant that makes twice as much peracetic acid and second, a two-phase reaction to generate the peracetic acid, which allows enzyme reuse. In addition, the eight pretreatment cycles are reduced to only one by increasing the volume of peracetic acid solution and increasing the temperature to 60 °C and the reaction time to 6 h. For the pretreatment step, the weight ratio of peracetic acid to wood determines the amount of lignin removed.     

Transient K<Superscript>+</Superscript> Current is Blocked by Lanthanum in <Emphasis Type="Italic">Drosophila</Emphasis> Neurons

The potassium A-current (IK_A) is important in regulating the membrane potential between action potentials. The whole-cell patch-clamp technique was applied to cultured Drosophila neurons derived from embryonic neuroblasts. IK_A was measured from neurons before and after application of 0.1 mM lanthanum to the external saline. IK_A was smaller in the lanthanum-containing saline (7±1 pA) than in the control saline (34±6 pA). Activation and inactivation of IK_A were unchanged by lanthanum. These results suggest that lanthanum neurotoxicity may lead to increased neuronal excitability. Moreover, given this inhibition of IK_A, lanthanum should not be used to block calcium current in studies of K⁺ currents.     

Ensemble analysis of angiogenic growth in three-dimensional microfluidic cell cultures

We demonstrate ensemble three-dimensional cell cultures and quantitative analysis of angiogenic growth from uniform endothelial monolayers. Our approach combines two key elements: a micro-fluidic assay that enables parallelized angiogenic growth instances subject to common extracellular conditions, and an automated image acquisition and processing scheme enabling high-throughput, unbiased quantification of angiogenic growth. Because of the increased throughput of the assay in comparison to existing three-dimensional morphogenic assays, statistical properties of angiogenic growth can be reliably estimated. We used the assay to evaluate the combined effects of vascular endothelial growth factor (VEGF) and the signaling lipid sphingoshine-1-phosphate (S1P). Our results show the importance of S1P in amplifying the angiogenic response in the presence of VEGF gradients. Furthermore, the application of S1P with VEGF gradients resulted in angiogenic sprouts with higher aspect ratio than S1P with background levels of VEGF, despite reduced total migratory activity. This implies a synergistic effect between the growth factors in promoting angiogenic activity. Finally, the variance in the computed angiogenic metrics (as measured by ensemble standard deviation) was found to increase linearly with the ensemble mean. This finding is consistent with stochastic agent-based mathematical models of angiogenesis that represent angiogenic growth as a series of independent stochastic cell-level decisions.     

Differential patterns of serum concentration and adipose tissue expression of chemerin in obesity: Adipose depot specificity and gender dimorphism

Chemerin, a recognized chemoattractant, is expressed in adipose tissue and plays a role in adipocytes differentiation and metabolism. Gender- and adipose tissue-specific differences in human chemerin expression have not been well characterized. Therefore, these differences were assessed in the present study. The body mass index (BMI) and the circulating levels of chemerin and other inflammatory, adiposity and insulin resistance markers were assessed in female and male adults of varying degree of obesity. Chemerin mRNA expression was also measured in paired subcutaneous and visceral adipose tissue samples obtained from a subset of the study subjects. Serum chemerin concentrations correlated positively with BMI and serum leptin levels and negatively with high density lipoprotein (HDL)-cholesterol levels. No correlation was found between serum chemerin concentrations and fasting glucose, total cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides, insulin, C-reactive protein or adiponectin. Similarly, no relation was observed with the homeostasis model assessment for insulin resistance (HOMA-IR) values. Gender- and adipose tissue-specific differences were observed in chemerin mRNA expression levels, with expression significantly higher in women than men and in subcutaneous than visceral adipose tissue. Interestingly, we found a significant negative correlation between circulating chemerin levels and chemerin mRNA expression in subcutaneous fat. Among the subjects studied, circulating chemerin levels were associated with obesity markers but not with markers of insulin resistance. At the tissue level, fat depot-specific differential regulation of chemerin mRNA expression might contribute to the distinctive roles of subcutaneous vs. visceral adipose tissue in human obesity.     

Prostaglandin EP1 receptor down-regulates expression of cyclooxygenase-2 by facilitating its proteasomal degradation

The enzyme cyclooxygenase-2 (COX-2) is rapidly and transiently up-regulated by a large variety of signals and implicated in pathologies such as inflammation and tumorigenesis. Although many signals cause COX-2 up-regulation, much less is known about mechanisms that actively down-regulate its expression. Here we show that the G protein-coupled receptor prostaglandin E(1) (EP(1)) reduces the expression of COX-2 in a concentration-dependent manner through a mechanism that does not require receptor activation. The reduction in COX-2 protein is not due to decreased protein synthesis and occurs because of enhancement of substrate-independent COX-2 proteolysis. Although EP(1) does not interfere with the entry of COX-2 into the endoplasmic reticulum-associated degradation cascade, it facilitates COX-2 ubiquitination through complex formation. Blockade of proteasomal activity results in degradation of the receptor and concomitant recovery in the expression of COX-2, suggesting that EP(1) may scaffold an unknown E3 ligase that ubiquitinates COX-2. These findings propose a new role for the EP(1) receptor in resolving inflammation through down-regulation of COX-2.     

Cell-based chip for the detection of anticancer effect on HeLa cells using cyclic voltammetry

HeLa cells directly immobilized on gold-patterned silicon substrate were used to assess the biological toxicity of anticancer drugs (hydroxyurea and cyclophosphamide). Immobilization of HeLa cells was confirmed by optical microscopy, and cell growth, viability and drug-related toxicity were examined by cyclic voltammetry and potentiometric stripping analysis. The voltammetric behaviors of HeLa cells displayed a quasi-reversible pattern with the peak current exhibiting a linear relationship with cell number. The attached living cells were exposed to different concentrations of hydroxyurea and cyclophosphamide as anticancer drugs, which induced the change of cyclic voltammetry current peak. As the exposed concentration of anticancer drugs was increased, the change of current peak was increased, which indicates the decrease of cell viability. Trypan Blue dyeing was performed to confirm the results of the effect of anticancer drugs on the cell viability which was obtained from cyclic voltammetry assay. The proposed direct cell immobilization method technique can be applied to the fabrication of cell chip for diagnosis, drug detection, and on-site monitoring.     

Lipid biomarkers, pigments and cyanobacterial diversity of microbial mats across intertidal flats of the arid coast of the Arabian Gulf (Abu Dhabi, UAE)

Variations in morphology, fatty acids, pigments and cyanobacterial community composition were studied in microbial mats across intertidal flats of the arid Arabian Gulf coast. These mats experience combined extreme conditions of salinity, temperature, UV radiation and desiccation depending on their tidal position. Different mat forms were observed depending on the topology of the coast and location. The mats contained 63 fatty acids in different proportions. The increased amounts of unsaturated fatty acids (12–39%) and the trans/cis ratio (0.6–1.6%) of the cyanobacterial fatty acid n- 18:1ω9 in the higher tidal mats suggested an adaptation of the mat microorganisms to environmental stress. Chlorophyll a concentrations suggested lower cyanobacterial abundance in the higher than in the lower intertidal mats. Scytonemin concentrations were dependent on the increase in solar irradiation, salinity and desiccation. The mats showed richness in cyanobacterial species, with Microcoleus chthonoplastes and Lyngbya aestuarii morphotypes as the dominant cyanobacteria. Denaturing gradient gel electrophoresis patterns suggested shifts in the cyanobacterial community dependent on drainage efficiency and salinity from lower to higher tidal zones. We conclude that the topology of the coast and the variable extreme environmental conditions across the tidal flat determine the distribution of microbial mats as well as the presence or absence of different microorganisms.