Modified streptavidin-biotin based lateral flow test strip for rapid detection of SARS-CoV-2 S1 antigen in saliva samples.

Compared to other infectious diseases, for which LFT development can take years, SARS-CoV-2 antigen LFTS were developed and deployed within months. LFTS for antigen detection were adopted on an unprecedented scale during the COVID-19 pandemic, but many of them lack the sensitivity especially for samples with low viral load. In our previous work, we developed an enhanced signal strip for detection of SARS CoV-2 SI antigens in saliva. Here we introduce some modification to improve the sensitivity, and specificity, and to lower the cost of the strip, by using biotin streptavidin (BS) system. In the modified BS strip, gold-streptavidin and biotinylated Nanobodies (Nbs) against S1 antigen were externally mixed with the tested samples (saliva or nasopharyngeal swab) before their application on the sample pad of the test strip containing angiotensin converting enzyme (ACE-2), as the capturing probe. The study included 320 individuals, with 180 being positively confirmed by RT-PCR and 140 confirmed negative, as well as, 45 health care workers, who were responsible for screening and handling of surgical cases in General Surgery Department and COVID clinic of TBRI. Our results proved that modified BS strip improved the overall sensitivity and specificity of S1antigen detection in saliva samples (95.21% and 99.29% respectively) compared to our previously developed enhanced LFTS (91.66% and 98.57% respectively). Also, the sensitivity of cases with Ct ≤ 30, Ct ≤ 35, and Ct ≤ 40 using the modified BS strip showed higher values (98.54%, 95.38%, and 88.89% respectively), compared to the corresponding results of our previously developed enhanced LFTS (95.86%, 92.31%, and 82.22% respectively). There were no cross-reactions with either Middle East respiratory syndrome corona virus MERS-CoV or SARS-CoV antigens. Furthermore, we found that the lower viral detection limit (LVD) of BS strip was obviously lower than our previous LVD limit of the enhanced LFTS (0.2 × 104 copies/ml vs. 0.4 × 104 copies/ml, respectively). Our developed BS strip showed that saliva samples gave better results than nasopharyngeal swabs of the same patients. The fact of using smaller amounts of Nbs, and ACE2, as well as the dispensing off of conjugate pad when applying BS strip modifications, justified the expected reduction in the costs of the strip. The implementation of BS strips on saliva samples of 45 health co-workers, who were tested 4 and 6 days after exposure to infection, showed an increase in the sensitivity, starting from the 4th day and reaching its highest level on the 6th day in both high risk and paramedic groups (90.9%, and 80.0%, respectively). This study provides evidence that employment of the modified BS system could increase the sensitivity of the strips, lower their cost, and render them an effective screening tool for early detection of the virus in saliva of suspected Covid-19 patients.

Serum IgE and Allergy Related Genotypes of IL-4R α and IL-13 Genes: Association with Glioma Susceptibility and Glioblastoma Prognosis.

Gliomas are the commonest type of primary brain tumor in adult. Glioblastoma maltiforms (GBM) is the malignant form with poor prognosis. Certain genotypes of inflammatory gene which associated with asthma and allergic conditions (IL-4R α and IL- 13) are inversely associated with glioma risk. We studied the relation between allergic conditions and serum level of IgE and glioma risk. We also examined the role of SNP of inflammatory genes IL-4 R α (rs 1801275) and IL-13 (rs 1800925) in development of glioma and to find out factors which can modify the prognosis of glioblastoma. This study included 98 Egyptian glioma cases and 98 healthy controls. Full history and clinical data were taken; total serum IgE were assayed, genotyping of IL-4 R α (rs 1801275) and IL-13 (rs 1800925) genes was carried out by restriction digestion after genes amplification. In cases group histopathological examination and tumor grading were done. Past history of allergic condition and elevated serum levels of IgE were more frequent in controls than in cases group (P< 0.05). Genotypes AA and AG of IL- 4R α were significantly frequent in cases and A allele were considered risk factor for glioma OR 2.31(1.53- 3.48), P < 0.001. We also found that C allele of IL-13 is risk factor for glioma susceptibility with p value = 0.006. Longer median survival period in glioblastoma were associated with elevated serum IgE level and who were AA genotypes of IL-4 R α. We conclude an inverse relation between glioma risk, and allergy biomarker IgE and allergy related (IL-4R α; rs 1801275) gene polymorphisms. GBM patients with IL-4Rα AA genotype, have longest survival. Chemotherapy and gross total resection improve GBM prognosis.

Preliminary experience with laparoscopic common bile duct exploration.

BACKGROUND: Herein we present our experience with laparoscopic common bile duct exploration (LCBDE) in managing common bile duct stones. METHODS: Data of 129 consecutive patients who underwent laparoscopic cholecystectomy (LC) and LCBDE done at our institutes from April 2011 through June 2016 were prospectively recorded and retrospectively reviewed. RESULTS: Since 2011, 3012 laparoscopic cholecystectomy were performed at our institutes, intraoperative cholangiogram (IOC) was done in 295 (9.8%) patients which detected choledocholithiasis in 129 (4.3%) of them. LCBDE was successful to clear the common bile duct (CBD) in 123/129 (95.4%). Six patients underwent postoperative endoscopic retrograde cholangiopancreatography (ERCP) because of incomplete CBD clearance (4 cases), symptomatic stenosed papilla (2 cases). LCBDE was performed in 103 patients via trans-cystic approach and choledochotomy one in 26 patients. In the choledochotomy group, seven patients had primary closure of the CBD, CBD was closed over T-tube in nine patients whereas the remaining 10 patients the CBD was closed over antegrade inserted stent. The median time of hospital stay was 4 (range; 1-15) days. No patients showed retained CBD stones with mean follow up was 9 ± 3.4 months. CONCLUSION: LCBDE is a safe and cost effective option for CBD stones in short-term outcome and can be performed provided proper laparoscopic expertise and facilities are available.

Protective effect of resveratrol against doxorubicin-induced cardiac toxicity and fibrosis in male experimental rats.

The possible effectiveness of resveratrol, a polyphenol present in different plants comprising berries, grapes and peanuts, on the prevention of doxorubicin-induced cardiac toxicity and fibrosis was investigated. Forty adult male Wistar albino rats were divided into four groups. Group I received normal saline, group II gavaged with resveratrol (20 mg/kg, daily for 4 weeks), group III received doxorubicin (2.5 mg/kg i.p. in six injections for 2 weeks; accumulative dose of 15 mg/kg), and group IV received doxorubicin + resveratrol (starting resveratrol intake 2 weeks before doxorubicin administration). Resveratrol significantly alleviated the increase in left ventricular lipid peroxidation, hydroxyproline, and tumor necrosis factor alpha levels as well as serum creatine kinase-myocardial band (CK-MB) activity and prevented the decrease in body and heart weights in doxorubicin-treated group. However, a marked protection against reduced glutathione content depletion and superoxide dismutase activity reduction was observed in the left ventricles of rats pretreated with resveratrol in combination with doxorubicin. Resveratrol also ameliorated the up-regulation of left ventricular caspase-3 and transforming growth factor-beta1 gene expression as well as left ventricular histopathological changes including necrosis and fibrosis induced by doxorubicin. Collectively, our results suggest that resveratrol provides a significant protection against doxorubicin-induced cardiotoxicity and fibrosis in rats. Therefore, it may be used as a promising cardioprotective agent in patients treated with doxorubicin due to malignant diseases. So, further clinical trials are required to confirm these findings.