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Purpose: Due to the high expense of obtaining and accessing scientific research, readers with diverse financial abilities are not offered equal opportunities. This study investigates the preferences for journal access types among Arab university academics and explores the implications of publishing research articles in open access vs closed access journals in low- and lower-middle income countries. Design/methodology/approach: An online survey and an in-person focus group consisting of 74 scholars from Arab institutions throughout the Arab World were conducted. Findings: Findings show that most professors at Arab universities favour open access publication without author fees. The results also show that this method of publishing research will help these nations advance by giving all citizens equal access to information and providing researchers with a good opportunity to be read and cited, which contributes to the overall progress of science. Originality/value: This topic has not been investigated yet, and it is of great importance to university professors and stakeholders in higher education institutions in the Arab world.

This study investigated the effects of classwide peer tutoring (CWPT) on word attack skills among students with learning disabilities (LD). The participants included 5 students with LD in the control group and 4 students with LD in the CWPT experimental group; all of the students were in the third grade in Najran, Kingdom of Saudi Arabia (KSA). The word attack test (WAT) was developed and administered to the two groups as the pretest and posttest. The students in the experimental group received instruction through CWPT, whereas the students in the control group received individual instruction. In the WAT posttest, the mean rank of the students in the experimental group was significantly higher than that of the control group. [This research project was funded by the Deanship of Scientific Research in Najran University, KSA, under the grant number (NU/SHED15/124).]

This study reviews three university ranking methodologies: Quacquarelli Sysmonds University Rankings, The Times Higher Education World University Rankings, and the Shanghai Jiao Tong University's Academic Ranking of World Universities. It also aims to suggest two new methodologies, one for World University Ranking and one for Arab University Ranking, and to propose data collecting tools for the new indicators if any. An online survey which elicited quantitative data and two focus-group discussions which produced qualitative data were used. The results of the survey show that the importance of some indicators as ranked by the respondents was similar to those found in the three international ranking systems, while others were not. The focus-groups suggested new weights for the indicators, since ranking systems overlook the differences between the institutions, resulting in unfair assessment of universities in the Arab region. Thus, new sub-indicators were proposed for both ranking systems.

For the first time, we quantify cost, footprint, and reliability implications of deploying hydrogen-based generation in off-grid electric vehicle charging stations (CS) using an optimization model coupled with a geographic information system (GIS) analysis for the city of Riyadh, Saudi Arabia. We also account for the challenges associated with wind energy deployment as a candidate generation technology within city centers. The analysis was restricted to carbon-free technologies: photovoltaics (PV), wind, battery, and hydrogen fuel-cells. At current prevailing technology costs, hydrogen can reduce the required footprint of off-grid CSs by 25% at a small incremental cost increase without impacting the charging reliability. By 2030, however, hydrogen will simultaneously provide the footprint and cost advantages. If we allow as little as 5% of the annual load to be unmet, the required footprint of the CS decreases by 60%. The levelized cost of energy values for the CS by 2030 can range between 0.13 and 0.20 $/kWh depending on learning-curve assumptions. The footprints calculated are then mapped to five land parcel categories in Riyadh: gas station, hospital, mall, school, and university. Incorporating hydrogen in CS design increases the number of parcels that could accommodate CSs by 15–45% via reducing the required PV array (i.e., footprint). • We assess the benefits that hydrogen can bestow upon off-grid charging stations. • Analysis conducted using a power optimization model and GIS analysis. • By 2030, hydrogen can reduce the cost and required footprint of charging stations. • Hydrogen can reduce the footprint requirement of charging stations by 25%. • Hydrogen enables 15–45% more land parcels to host charging stations in Riyadh. [ABSTRACT FROM AUTHOR]

Nowadays, endophytic fungi represent a rich source of biological active compounds. In the current study, twelve endophytic fungal species were isolated from Avicennia marina leaves. From the isolates, Aspergillus niger, Penicillium rubens and Alternaria alternata recorded the highest isolation frequency (80%), relative density (12.5%) and antimicrobial activity. The antimicrobial and anticancer activities of P. rubens were more effective than those of A. niger and A. alternata; therefore, its identification was confirmed via the ITS rRNA gene. Filtrate extracts of P. rubens, A. alternata and A. niger were analyzed using GC-MS and showed different detected constituents, such as acetic acid ethyl ester, N-(4,6-Dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide, 1,2-benzenedicarboxylic acid, hexadecanoic acid and octadecanoic acid. Filtrate extract of P. rubens exhibited the presence of more compounds than A. alternata and A. niger. Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigatus were more inhibited by P. rubens extract than A. alternata or A. niger, with inhibition zones of 27.2 mm, 22.21 mm, 26.26 mm, 27.33 mm, 28.25 mm and 8.5 mm, respectively. We observed negligible cytotoxicity of P. rubens extract against normal cells of human lung fibroblasts (WI-38 cell line), unlike A. alternata and A. niger extracts. Proliferation of prostate cancer (PC-3) was inhibited using P. rubens extract, exhibiting mortality levels of 75.91% and 76.2% at 200 µg/mL and 400 µg/mL of the extract. Molecular docking studies against the crystal structures of C. albicans (6TZ6) and the cryo-EM structure of B. subtilis (7CKQ) showed significant interactions with benzenedicarboxylic acid and N-(4,6-dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide as a constituent of P. rubens extract. N-(4,6-dimethyl-2-pyrimidinyl)-4-(4-nitrobenzylideneamino) benzenesulfonamide had the highest scores of −6.04905 kcal/mol and −6.590 kcal/mol towards (6tz6) and (7CKQ), respectively. [ABSTRACT FROM AUTHOR]

Strategies based on halo- and thermostable enzymes are promising and attractive for biotechnological applications. Three fungal isolates, namely Aspergillus flavus, Cladosporium cladosporioides, and Alternaria alternata, and were subjected to chitinase production using a medium with different concentrations of NaCl up to 10%. C. cladosporioides was found to be the main chitinase producer at high concentration of NaCl; therefore, its identification was confirmed using 18S rDNA. The highest chitinase production (88.67 U/mL) was obtained by C. cladosporioides, followed by A. flavus (76.17 U/mL), and A. alternata (70.67 U/mL) at 5% NaCl, while their production without NaCl was 35.07 U/mL, 22.83 U/mL, and 21.33 U/mL, respectively. Thermal stability of chitinase was recorded at 50 °C at 20 min. Chitinase halostability at 20 min indicated that 10% NaCl was the optimum level, with activity 88.3 U/mL. Safranin dye decolorization by C. cladosporioides was enhanced to 88.25% via the addition of 5% NaCl to growth medium containing chitin. The inhibitory activity of chitinase was detected against C. lunata and F. oxysporium with or without NaCl. Culex pipiens larvae were more affected by C. cladosporioides chitinase produced at 5% than 10% NaCl. Energy scores of the molecular docking investigations confirmed the insecticidal activity of chitinase against C. pipiens larvae. [ABSTRACT FROM AUTHOR]

The activity levels of 226Ra, 232Th, and 40K in 38 soil samples collected from four areas (Al Assyah, Buraidah, Al Shamassea, and Al Badayyia) in Qassim (Saudi Arabia) were determined by γ-ray spectrometry with a NaI(Tl) detector. The activity concentrations of 226Ra, 232Th, and 40K varied from 9.6 ± 0.2 to 158.6 ± 0.1, from 9.6 ± 0.1 to 110.0 ± 0.4, and from 70.1 ± 0.5 to 390.3 ± 1.5 Bq/kg, respectively. Also, the annual effective dose rate was estimated to assess the health hazards caused by the external exposure to people living in these regions. The concentrations of 40K and 232Th are lower than the world average, whereas the 226Ra concentration is higher than the recommended level detailed by UNSCEAR. [ABSTRACT FROM AUTHOR]

Smokeless tobacco (SLT) has been reported to have deleterious effects on the health of its users. This study aims to analyze the constituents of locally collected SLT sample extracts (S1–S11) from Tabuk region of Saudi Arabia using GC-MS and investigate their cytotoxic effect on human gingival fibroblasts (hGFs), normal human fibroblasts (MRC5), and two cancer cell lines (HT29 and HepG2) using MTT assay. GC-MS results showed that pyridine, 3-(1-methyl-1H-pyrrol-2-yl)-, tetracyclo[4.4.1.1(7,10).0(2,5)]dodec-3-en-11-ol, and cotinine were found in S1, while ethyl iso-allocholate was traced in S2. Compounds 9,12-octadecadienoic acid, ethyl ester, 7-methyl-Z-tetradecen-1-ol acetate, cis-10-heptadecenoic acid and octadecanoic acid, ethyl ester, and nicotine traces were found in S4, while compound 3,7,11,15-tetramethyl-2-hexadecen-1-ol, tetradecamethyl-hexasiloxane, and phytol in S5. Additionally, octadecamethyl cyclononasiloxane, oleic acid, and trimethylsilyl ester were found in S6 and S9, respectively. Interestingly, extracts S4, S10, and S6 were the most cytotoxic to the normal fibroblasts (hGF and MRC5, with low selectivity index: <1), compared with doxorubicin and with their effect on the cancerous cells (HT29 and HepG2). Various components detected in SLT samples were carcinogenic, including nicotine and its derivatives, hexadecanoic acid, 1,2-benzenedicarboxylic acid, and octadecanoic acid. The present study showed that the cytotoxic and possibly carcinogenic effects of the SLT samples on gingiva and lung cells are attributed to many compounds and not only nicotine derivatives, all of which could create health threats for SLT users and lead to various types of cancers, including oral, lung, colon, and liver cancers. [ABSTRACT FROM AUTHOR]

Introduction: Vitamin D Deficiency (VDD) and several other metabolic factors are known to be involved in the aggravation of Osteoarthritis (OA). A better understanding of the role of these metabolic factors and diseases is required to alleviate the OA progression. Aim: To analyse the prevalence of VDD in OA patients and its correlation with co-morbidities such as diabetes, hypertension (HT), cardiovascular disease and acidity and also to assess the effect of Body Mass Index (BMI) and increasing age on the developmental process of OA. Materials and Methods: A cross-sectional survey was undertaken during September 2018 to March 2019 in King Khaled, King Salman and Hail General Hospitals located in Ha'il province of Kingdom of Saudi Arabia (KSA). The study included 501 participants of OA patients that visited these hospitals. Data pertaining to the variables in this study such as diabetes, HT, cardiovascular problems, vitamin D and calcium deficiency, acidity and anthropometric details was obtained using a structured questionnaire. Data analysis was done using descriptive statistics and Pearson's correlation with the statistical program SPSS Version 21. Results: VDD, calcium deficiency and acidity were the most prevalent factors observed in the patients. Vitamin D and calcium deficiency was observed to be higher in females than males. VDD significantly correlated to diabetes, HT, acidity and age, both in females and males. Cardiovascular disease and BMI correlated with VDD only in males but not in females. BMI showed positive correlation with HT in males (p<0.01) but not females, and also correlated with age (p<0.01) irrespective of gender. Conclusion: The study found that VDD is more prevalent in females than males in Ha'il region. It is correlated to variables such as diabetes, HT, acidity, BMI and increasing age, which are identified as risk factors contributing to the progression of OA. [ABSTRACT FROM AUTHOR]

Background and Aim of the Work: Portal vein thrombosis (PVT) is a serious condition; however, the outcome may be improved by early recognition and prompt management. The aim of this multicenter retrospective study is to evaluate the underlying risk factors, pattern of presentation, methods of diagnosis, and results of treatment of cases of acute/recent PVT in Taif tertiary hospitals.Methods: In this chart review and database study, 103 patients met the inclusion criteria. Data extracted from the medical records were analyzed for underlying risk factors, pattern of presentation, diagnostic tools, and results of treatment.Results: The underlying causes of PVT were cirrhosis (46.6%) and noncirrhotic causes (43.7%), and no obvious cause was recorded in 9.7% of cases. In 9.7% of the patients, PVT progressed to mesenteric venous occlusion. The diagnosis was established by initial duplex ultrasound scan or/and contrast-enhanced computed tomography scan in 97.1% of patients. Anticoagulation was started for all patients after established diagnosis except in patients with gastrointestinal bleeding. In all patients with mesenteric venous occlusion, infarcted segments were found and resected during abdominal exploration. The recorded overall mortality during follow-up was 51.5%, and it was significantly higher in cirrhotic than in noncirrhotic patients (P < 0.05).Conclusions: Cirrhosis is the main underlying cause of PVT in Taif, Saudi Arabia. Most of the findings in this study about epidemiological and risk factors were quite different from that of other global findings. More studies are required to assess the actual magnitude of PVT in Taif and other Saudi Arabia provinces. [ABSTRACT FROM AUTHOR]

Hydrodistilled essential oils (HD) of dried aerial parts of Achillea fragrantissima cultivated in Egypt and Madinah Monawara, Saudi Arabia, and their volatiles extracted by solid phase microextraction (SPME) were analyzed using Gas Chromatography – Mass Spectrometry. Thirty – four constituents of the essential oil of Egyptian A. fragrantissima were identified, representing 90.15% of the total oil constituents, while SPME revealed 15 components constituting 94.72% of the volatile material. Santolina alcohol, artemisia ketone, α-thujone, 4(10)-thujen-3-ol, β-thujone, yomogi alcohol and trans-sabinyl acetate were the predominant components in both extracts, with quantities varying with extraction method. Many terpenes e.g. β-pinene, sabinene, α-terpinene, p-cymene, linalool, p-menth-2-en-1-ol, 4(10)-thujen-3-ol, borneol, carvone, p-menth-1-en-3-one, bornyl acetate and germacrene D, were identified for the first time. α-Thujone, 4-terpineol, trans-pinocarveol, and spathulenol were the major components among 42 identified components accounting for 93.65% of the total identified volatiles of Madinah hydrodistillate. Monoterpenes concentration was higher in Madinah SPME volatile extract than in HD essential oil. A. fragrantissima essential oil of Madinah exhibited higher antioxidant activity (IC50 1.09 mg/ml) than did Egyptian oil (IC50 1.72 mg/ml), consistent with the differences in phenolic content and volatile constituents identified in both oils. [ABSTRACT FROM AUTHOR]

Japanese quails Coturnix coturnix japonica reared in economic farms were individually investigated for coccidian infections. The results indicated the absence of infections in birds younger than 1 month. An Eimeria infection rate of up to 80% was detected in birds 7–9 weeks old with a general infection rate of 29%. The infection rate decreased to 21.42% in birds older than 10 weeks. Morphometric characteristics of freshly shed, unsporulated oocysts were taken. These oocysts appeared pale yellow in color, were oval to subspherical in shape being limited by a bilayered oocyst wall of 1.2 µm. The unsporulated oocysts measured 17.73 ± 12.92 × 12.79 ± 1.69 µm (mean of 100) and possessed a polar granule, a micropyle and an oocyst residuum. The sporulation took 72 h and resulted in the formation of four elongated sporocysts containing two sporozoites, in addition to a stieda body and a sporocyst residuum. The life cycle of this Eimeria species was followed in experimentally infected quails. Three asexual generations (at 60, 78, and 96 h p.i.) were detected in the epithelium of the small intestine before the sexual cycle started at 84 h p.i. The prepatent period was 5 days, while the patent period covered 6–7 days. Besides this well-defined species, another Eimeria species occurred, the oocysts of which were excreted in low numbers and were characterized by the absence of a micropyle and an oocyst residuum. These oocysts measured 15.73 ± 2.22 × 14.18 ± 1.89 µm (mean of 100) and sporulated already within 60 h. [ABSTRACT FROM AUTHOR]

Abstract  In the present study, sarcocysts of a Sarcocystis species infecting the gecko Hemidactylus turcicus was investigated by light and transmission electron microscopy. Six out of 26 (23%) H. turcicus were found to be infected with cysts of Sarcocystis. Examined muscle samples of different sites showed high intensity of infection in the tail and hind limb skeletal muscles. Microscopically visible cysts reached a mean size of 80 × 720 μm. These cysts are characterized by a light microscopically thick cyst wall and inner prominent septa dividing their interior into a large number of compartments enclosing the different zoites. Ultrastructural characteristics of the primary cyst wall and its long, mostly not upright protrusions were investigated. Two widely differentiated zoites (metrocytes and cyst merozoites) were clearly identified; they all showed the characteristic architecture of the Apicomplexa and especially that of the genus Sarcocystis. The about 5–7 μm sized cyst merozoites seemed to be differentiated into those being either poorly or richly supplied with reserve materials (amylopectin, lipids). This finding may indicate the existence of different developmental stages. Events of endodyogeny represented the only mode of reproduction inside the cysts. While comparing the morphology of these cysts with other descriptions of cysts in reptiles, they were described as a new species (Sarcocystis turcicii). [ABSTRACT FROM AUTHOR]

The seasonal occurrence of spider community belonging to 10 families was determined in three different habitats: vegetable, date-palm and mixed weed habitats in Western Saudi Arabia. Different densities were observed in all habitats, however the vegetable habitat showed high number of spiders. This may be due to variability of food sources. The wolf spider family (Lycosidae) was predominant in all habitats. Moreover the analysis of variance showed that 3 families Lycosidae, Zodariidae and Pholcidae had significant differences when their densities were compared between the three habitats. The number of generations vary between 2 and 3 throughout the seasons. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the members of the dung beetles superfamily Scarabaeiodea in three agroecosystems in Western Saudi Arabia. Methodology of the study; Results and discussion on the study.

Presents information on a study which determined the density of the phytophagous curculionid weevil complex belonging to one family and subfamilies in different ecotypes including date-palm vegetable and natural habitats in Western Saudi Arabia. Methodology of the study; Results and discussion on the study.

Solar radiation prediction is an important process in ensuring optimal exploitation of solar energy power. Numerous models have been applied to this problem, such as numerical weather prediction models and artificial intelligence models. However, well-designed hybridization approaches that combine numerical models with artificial intelligence models to yield a more powerful model can provide a significant improvement in prediction accuracy. In this paper, novel hybrid machine learning approaches that exploit auxiliary numerical data are proposed. The proposed hybrid methods invoke different machine learning paradigms, including feature selection, classification, and regression. Additionally, numerical weather prediction (NWP) models are used in the proposed hybrid models. Feature selection is used for feature space dimension reduction to reduce the large number of recorded parameters that affect estimation and prediction processes. The rough set theory is applied for attribute reduction and the dependency degree is used as a fitness function. The effect of the attribute reduction process is investigated using thirty different classification and prediction models in addition to the proposed hybrid model. Then, different machine learning models are constructed based on classification and regression techniques to predict solar radiation. Moreover, other hybrid prediction models are formulated to use the output of the numerical model of Weather Research and Forecasting (WRF) as learning elements in order to improve the prediction accuracy. The proposed methodologies are evaluated using a data set that is collected from different regions in Saudi Arabia. The feature-reduction has achieved higher classification rates up to 8.5% for the best classifiers and up to 15% for other classifiers, for the different data collection regions. Additionally, in the regression, it achieved improvements of average root mean square error up to 5.6 % and in mean absolute error values up to 8.3%. The hybrid models could reduce the root mean square errors by 70.2% and 4.3% than the numerical and machine learning models, respectively, when these models are applied to some dataset. For some reduced feature data, the hybrid models could reduce the root mean square errors by 47.3% and 14.4% than the numerical and machine learning models, respectively. [ABSTRACT FROM AUTHOR]

The incidence of Extended-spectrum β-lactamase (ESBL)-encoding genes (blaCTX-M and blaTEM) among Gram-negative multidrug-resistant pathogens collected from three different countries was investigated. Two hundred and ninety-two clinical isolates were collected from Egypt (n = 90), Saudi Arabia (n = 162), and Sudan (n = 40). Based on the antimicrobial sensitivity against 20 antimicrobial agents from 11 antibiotic classes, the most resistant strains were selected and identified using the Vitek2 system and 16S rRNA gene sequence analysis. A total of 85.6% of the isolates were found to be resistant to more than three antibiotic classes. The ratios of the multidrug-resistant strains for Egypt, Saudi Arabia, and Sudan were 74.4%, 90.1%, and 97.5%, respectively. Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa showed inconstant resistance levels to the different classes of antibiotics. Escherichia coli and Klebsiella pneumoniae had the highest levels of resistance against macrolides followed by penicillins and cephalosporin, while Pseudomonas aeruginosa was most resistant to penicillins followed by classes that varied among different countries. The isolates were positive for the presence of the blaCTX-M and blaTEM genes. The blaCTX-M gene was the predominant gene in all isolates (100%), while blaTEM was detected in 66.7% of the selected isolates. This work highlights the detection of multidrug-resistant bacteria and resistant genes among different countries. We suggest that the medical authorities urgently implement antimicrobial surveillance plans and infection control policies for early detection and effective prevention of the rapid spread of these pathogens. [ABSTRACT FROM AUTHOR]

[Display omitted] • The central Asir Shear Zone (CASZ) has experienced multiple stages of deformation. • The deformation history of CASZ included dextral shearing switching to sinistral. • Emplacement of granitoids was controlled by N- to NNE strike-slip faults. • The CASZ records three pre-Tertiary deformation events. The Central Asir Shear Zone (CASZ) is a N- to NNE-oriented inhomogeneous strain zone parallel to the Nabitah shear belt in southern Saudi Arabia. It is ~200 km long and 20 km wide, and traverses the Asir terrane. The deformed terrains in the vicinity of the CASZ have experienced a prolonged history involving three successive phases of deformation: arc-collision, dextral transpression and sinistral strike-slip faulting. Remote-sensing data analysis and field investigation provide insights into the geological and structural features along the CASZ. Image transformation and enhancement reveal faults and folds, and discriminate between granitoids, metavolcanics, gabbros and younger (Ablah Group) sediments. The obtained evidence points to polyphase deformation of the area, characterized by narrow zones of high strain, folding and shearing enclosing slices of less deformed rocks. Lineament analysis shows predominantly NNE, NNW, N and NE trends of folds and shear zones, and NW, NE and E fracture trends. The CASZ has a >100 m.y. long deformation history, including a change from dextral to sinistral shearing. Both shearing senses are found on the older N-S and younger NW-SE fault systems. N-S oriented shearing was accompanied by intrusion of granitoids and localized hydrothermal alteration along N to NNE trending shear zones. Strain analysis shows low strain in the Ablah basin sediments, consistent with Ablah deposition after the tectonic climax in the region. [ABSTRACT FROM AUTHOR]

Background: Sources of student stress can be academic pressures, social or personal issues and medical students have to face the challenge of rigorous curriculum and also have to learn how to deal with emotionally difficult experiences., Aim of Work: Determination of the prevalence of stress and to identify the risk factors of stress among Saudi medical students at Faculty of Medicine, King Faisal University, Saudi Arabia., Methods: A survey study design was conducted among medical students at Faculty of Medicine, King Faisal University, Al Ahsaa Governorate, Eastern Province from February-May, 2013. Both male and female students were invited to participate in our study. The total number of students was 650 Saudi medical students, out of them 244 medical students were participated in the current study. All participants were provided a self administered questionnaire. A likert scale with 3 points for responses was used. Questionnaires were given to participants 2 month before end-semester examinations, to minimize the extra stress symptoms A score of stress was calculated., Results: Prevalence of stress was 53% among Saudi students. Gender has no role in stress among medical students (p > 0.05). Logistic regression analysis revealed the most important risk factors of stress, having places for recreation at the University showed a relationship with stress among medical students with a p value = 0.000, there is a statistically significant relationship between stress and having optimal place for studying outside the university p = 0.001, while, comparing number of sleeping hours with stress, we could not find a statistically significant relationship among medical students, p = 0.744. Medical students who had close friends to share with them their stresses and concerns showed a highly statistically significant relationship between stressed and unstressed students p = 0.001., Conclusion: Medical students reported high levels of stress. The most frequently occurring stressors among the students were related to academic and psychosocial domains. The associations between stressed cases and gender, occurrence of academic and psychosocial stressors need to be further tested by prospective studies.

As by the end of 1992, 96 (47 females; 49 females) patients were on regular dialysis treatment for end stage renal failure (ESRF) in 5 haemodialysis HD units, the Gassim region of Saudi Arabia. Because of lack of facilities, paediatric patients were under-represented, age range being 11 to 80 years. Systemic hypertension (47%), followed by hereditary/congenital conditions (23%) and non-insulin dependent diabetes mellitus NIDDM (19%) were the most common causes of ESRF in the region. One patients developed ESRF 14 years after donor nephrectomy. Overall prevalence of HCAb was 50% with a range of 17.24% to 83%. Based, especially, on the findings in two of the units which between them handle 57% (55/96) of the patients, we believe that the practice of machine isolation policy (MIP) rather than blood transfusion is largely responsible for this wide variation in prevalence between the centres. Considering the very high overall prevalence of the Kingdom, we suggest the MIP should no longer be optional and should be part of the universal infection precautions for HD patients. Comparing Gassim with findings from Taif, there may be some variation in the pattern of ESRF between different parts of the Kingdom. More reports will be needed to document this. Donor nephrectomy as a cause of ESRF is being recorded for the first time in the Kingdom. Vigilance is important. Similarly, we believe that sexual intercourse as a probable route of hepatitis C virus HCV transmission is being recorded for the first time in the Kingdom.