Genotoxicity of Glyphosate on Cultured Human Lymphocytes.

Glyphosate-based herbicides are the most used herbicides in the world. Despite being widely used, a dispute exists whether glyphosate-based herbicides have a negative effect on human health, particularly genotoxic effects. Therefore, the aim of this study was to investigate glyphosate genotoxicity on cultured human lymphocytes. Cultured human lymphocytes were treated with different concentrations of glyphosate (20, 40, and 200 µmol/L). Four toxicity measures were examined: frequency of chromosomal aberrations (CAs), frequency of sister-chromatid exchange (SCE), production of 8-OHdG, and cell kinetics analysis. The results show that glyphosate induced significant (P < 0.05) increases in the levels of SCE at the highest used concentration (200 µmol/L). However, no significant elevation in SCE levels was observed at the lower examined concentrations (20 and 40 µmol/L). No significant changes in CA were detected at all examined concentrations (P = 0.86). Also, glyphosate did not induce changes to the normal level of 8-OHdG at all examined concentrations (P = 0.98). Last, no significant changes in either mitotic index or proliferative index were observed at any examined concentrations (P > 0.05). The results collectively indicate a lack of genotoxicity and cytotoxicity of glyphosate in cultured human lymphocytes when dealing with environmentally relevant concentrations (20 and 40 µmol/L). However, being exposed to higher concentrations (200 µmol/L) led to slightly higher level of SCE. Therefore, we recommend cautionary measures when dealing with glyphosate-based herbicides for individuals, such as farmers, who may be extensively exposed to high concentrations of these herbicides.

Association of Irisin Circulating Level with Diabetic Retinopathy: A Case-Control Study.

Obesity and obesity induced type 2 diabetes development and progression have been associated with sedentary lifestyle. Irisin, a newly discovered myokine, has been demonstrated at lower levels in obese and type 2 diabetes patients compared to controls. The main aim of this study is to explore association of Irisin with diabetic retinopathy (DR). A total of 233 healthy and adults participated in this study. Participants were divided into four categories: a healthy control group and an age-match subset of patients with type 2 diabetes; a positive control group of patients with type 2 diabetes not affected by DR (No DR); and patients with type 2 diabetes affected by DR (non-proliferative DR (NPDR) and proliferative DR (PDR)). Plasma samples were quantified for Irisin measurement, lipid profile and HbA1c. Comparison of the age-matched groups of healthy controls and patients with type 2 diabetes revealed lower Irisin plasma level in type 2 diabetes group. Analyses revealed negative correlations of Irisin to HbA1c and LDL levels and positive correlation to HDL level. Comparing Irisin level in No DR and DR groups revealed a higher level in No DR group and analysis per DR classification indicated higher Irisin level in NPDR group. Our results demonstrate not only correlation of plasma Irisin level with DR stages, but also significantly different Irisin level among them. This is promising in terms of researching Irisin as a potential associating marker for type 2 diabetes and DR development and progression.

A cross-sectional study of basic education influence on the clinical training: Attitudes and perception among Jordanian medical students.

BACKGROUND: Over the past century, the medical educational model has been static with no significant improvement. Studies show that students are leaning towards a more active, dynamic, learner-centered education model that fits their needs and encourages them to be more responsible for their learning. Thus, we conducted this study to investigate Jordanian medical students' perceptions and attitudes towards the value of basic sciences in their clinical training. METHODOLOGY: This was a cross-sectional study that utilized an online, self-administered questionnaire targeting medical students in their clinical years. The questionnaire comprises 5 domains targeting students' perceptions, attitudes, and suggestions of the medical educational system in general and basic sciences in specific. RESULTS: Overall, 578 medical students completed the survey with a male to female ratio of 0.7, and 56% of participants studied were studying at Mutah University, while 42% were at the University of Jordan. Approximately three-fourth (73.9%) of the students reported that basic medical sciences are critical to their development as physicians. Approximately, 82% believe that it is vital to integrate the clinical practice into basic science teaching. Besides, 82.4% of students agreed that faculty members' teaching style influences the educational content's delivery at the basic level. Moreover, 73% of students lean towards the inclusion of problem-based learning into their curriculums. On the other hand, 41.7% of students reject basic science questions in their written clinical exams. CONCLUSION: Our study highlights the positive attitudes of Jordanian medical students towards basic medical sciences. It also demonstrates that students are more comfortable with an active and dynamic educational model that fits their needs and qualifications. Thus, we recommend a student-centered medical educational model trail to maximize learning and teaching efficiency and develop competent medical practitioners.

The understanding of research ethics at health sciences schools in Jordan: a cross-sectional study.

BACKGROUND: Research ethics is required for high-quality research that positively influences society. There is limited understanding of research ethics in Middle Eastern countries including Jordan. Here, we aim to investigate the level of understanding of research ethics principles among health sciences faculty members in Jordan. METHODS: This is a cross sectional study where faculty members from the University of Jordan were surveyed for their knowledge and, attitude of research ethics principles. The study was conducted in the period between July 2016 to July 2017 using a customized-design questionnaire involving demographic data and participants' contributions toward research, and assessment of participants' knowledge, belief and attitude towards research ethics. Different question-formats have been used including multiple-choice, yes or no, and a four point Likert-type questions. Obtained responses were tabulated according to gender, academic-rank, and knowledge about research ethics principles. RESULTS: The study had a response rate of 51%. Among the 137 participants of this study, most (96%) were involved in human and animal research, yet, only 2/3 had prior training in research ethics. Moreover, 91% believed that investigators should have training in research ethics and 87% believed that there should be a mandatory postgraduate course on that. The average correct scores for correct understanding of researchers towards research ethics was 62%. Yet, there were some misconceptions about the major ethical principles as only 43% identified them correctly. Additionally, the role of research ethics committees was not well understood by most of the respondents. CONCLUSIONS: Although there is acceptable knowledge about research ethics, discrepancies in understanding in research ethics principles seems to exist. There is a large support for further training in responsible conduct of research by faculty in health sciences in Jordan. Thus, such training should be required by universities to address this knowledge gap in order to improve research quality and its impact on society.

Antioxidant capacity and biomarkers of oxidative stress in saliva of khat-chewing patients: a case-control study.

OBJECTIVES: The aim of this study was to investigate the antioxidant levels and biomarkers of oxidative stress in saliva from khat-chewing patients compared with controls. STUDY DESIGN: Saliva samples were collected from 51 chronic khat chewers and 46 age- and sex-matched controls. Concentrations of oxidative stress biomarkers (malonyl-dialdehyde [MDA], protein carbonyl, and 8-hydroxy-2'-deoxyguanosine) and antioxidant defense (total antioxidant capacity [TAC], superoxide dismutase, glutathione peroxidase, and catalase [CAT) were analyzed. RESULTS: Salivary MDA level in the khat users group (45 ± 9.2 nmol/mL) was significantly increased in comparison with controls (13 ± 2.1 nmol/mL; P < .001), but there were no significant differences between the 2 groups regarding the levels of salivary protein carbonyl and oxidized guanine species. Salivary TAC was significantly reduced in khat users (0.25 ± 0.028 mmol/L) in comparison with controls (0.34 ± 0.037 mmol/L). Salivary CAT level was significantly reduced in khat users (6.0 ± 0.47 U/mL) in comparison with controls (7.7 ± 0.43 units/mL; P <.05), but no significant differences were observed between the 2 groups with regard to salivary superoxide dismutase or glutathione peroxidase levels. CONCLUSIONS: Chronic khat chewing is associated with increased levels of salivary MDA and reduced levels of TAC and CAT among a population of adult men in comparison with non-khat-chewing controls. These findings suggest that the pro-oxidative effect of khat chewing may be a contributing mechanism for various oral diseases associated with khat use, including cancer, periodontitis, and caries.

N-Acetyl Cysteine Therapy Does Not Prevent Renal Failure in High-Risk Patients Undergoing Open-Heart Surgery.

BACKGROUND: Renal dysfunction is a common complication after cardiovascular surgery. Controversial issues have been discussed regarding the role of N-acetyl cysteine in the prevention of postoperative renal dysfunction. The purpose of this meta-analysis is to assess whether N-acetyl cysteine offers any protection against the development of acute renal dysfunction after cardiac surgery. METHODS: Multiple databases were searched for randomized trials comparing the role of N-acetyl cysteine and placebo in human patients undergoing cardiac surgery. End-points studied were: the incidence of acute renal failure, hemodialysis, early mortality, duration of hospital stay, and maximal change in creatinine values. Dichotomous variables were compared using the risk difference (RD) calculated with inverse weighting; continuous data was pooled as (standardized) mean difference. Results are presented with 95% confidence interval (P < .05 is significant); results are presented within 95% confidence interval. RESULTS: Thirteen randomized trials (713 and 707 patients in the N-acetyl cysteine and control groups, respectively) were included in the present analysis; nine dealing with patients at high-risk for acute renal failure. The incidence of postoperative acute renal dysfunction was 23% and 36% in the N-acetyl cysteine and control cohorts, respectively. N-acetyl cysteine therapy did not reduce acute renal dysfunction in the high-risk cohort [RD -0.03 (-0.09 to 0.02); P = .22; I2 = 24%]. Maximal change in creatinine levels after surgery was also comparable [standardized mean difference 0.07 (-0.23, 0.09); P = .39]. Early mortality was 2.9% and 3.7% in the N-acetyl cysteine and control cohorts respectively; [RD 0 (-0.03 to 0.02); P = .63; I2 = 20%]. Hospital stay (mean length of stay 10.4 and 10.1 days in the N-acetyl cysteine and control cohorts, respectively) was also similar in both cohorts [WMD 0.17 (-0.02 to 0.37) days; P = .81]. CONCLUSION: Prophylactic N-acetyl cysteine therapy does not reduce the incidence of renal dysfunction in high-risk patients undergoing cardiac surgery.

Mutagenesis of tryptophan199 suggests that hopping is required for MauG-dependent tryptophan tryptophylquinone biosynthesis.

The diheme enzyme MauG catalyzes the posttranslational modification of the precursor protein of methylamine dehydrogenase (preMADH) to complete biosynthesis of its protein-derived tryptophan tryptophylquinone (TTQ) cofactor. Catalysis proceeds through a high valent bis-Fe(IV) redox state and requires long-range electron transfer (ET), as the distance between the modified residues of preMADH and the nearest heme iron of MauG is 19.4 Å. Trp199 of MauG resides at the MauG-preMADH interface, positioned midway between the residues that are modified and the nearest heme. W199F and W199K mutations did not affect the spectroscopic and redox properties of MauG, or its ability to stabilize the bis-Fe(IV) state. Crystal structures of complexes of W199F/K MauG with preMADH showed no significant perturbation of the MauG-preMADH structure or protein interface. However, neither MauG variant was able to synthesize TTQ from preMADH. In contrast, an ET reaction from diferrous MauG to quinone MADH, which does not require the bis-Fe(IV) intermediate, was minimally affected by the W199F/K mutations. W199F/K MauGs were able to oxidize quinol MADH to form TTQ, the putative final two-electron oxidation of the biosynthetic process, but with k(cat)/K(m) values approximately 10% that of wild-type MauG. The differential effects of the W199F/K mutations on these three different reactions are explained by a critical role for Trp199 in mediating multistep hopping from preMADH to bis-Fe(IV) MauG during the long-range ET that is required for TTQ biosynthesis.