The black seed Nigella sativa (N. sativa) is a type of plant that belongs to the Ranunculaceae family.1 It has been used as a herbal medicine for more than 2000 years. It is also used as a food additive and flavor in many countries. N. sativa volatile oil has recently been shown to possess 67 constituents, many of which are capable of inducing beneficial pharmacological effects in humans.2Studies on the effect of N. sativa on blood glucose levels in normal and diabetic animals seem to be conflicting. In 1985, Al-Awadi et al.3 reported a significant decrease in blood glucose produced by a plant mixture containing N. sativa in normal and streptozotocin-induced diabetic rats, however, when N. sativa was used alone it produced no effect on the blood glucose level of both normal and diabetic rats.4 Also, El-Naggar and El-Deib 5 reported that oral administration of powdered N. sativa seeds for three weeks produced minimal insignificant reduction in blood glucose in normal and alloxan-induced diabetic rats. On the other hand, the intraperitoneal administration of volatile oil of N. sativa to fasting normal and alloxon-diabetic rabbits produced significant hypoglycemic effects.6 A plant mixture containing N. sativa administered once daily at doses of 0.5-1.5 mL/kg body weight for one month to normal and diabetic rats produced significant reductions in serum glucose level only in diabetic rats.7 Another plant mixture containing N. sativa was also reported to produce a significant hypoglycemic effect in alloxan-induced diabetic rats. 8 The only study which has been done on humans reported a significant decrease in blood glucose level after one week of oral ingestion of N. sativa powder at a dose of 2 g/day.9 The glucose level went up but remained insignificantly below baseline by the end of two weeks. We conducted the current study in an attempt to shed some light on the effect of N. sativa on blood glucose. Materials and MethodsA total of 300 tested and 100 control white female albino rats were included in the study. The rats, which weighed 180-220 g, were fed on standard ad labitum and normal drinking water. The tested animals were divided into two main groups of 150 each. One group received N. sativa seeds and the other was given intraperitoneal injections of thymoquinone (Sigma Chemicals, USA). Each tested group was then subdivided into six groups of 25 rats each, with each group receiving different drug doses. N. sativa groups were fed different amounts of black seed of 50, 100, 200, 300, 400 and 500 mg/day, respectively. Each dose was mixed with flour, making a small amount of dough of around 2.5 g weight, before feeding. Thymoquinone groups were given intraperitoneal injections of different thymoquinone concentrations dissolved in ethanol and diluted with normal saline, and were 0.5, 1, 2, 4, 6 and 8 mg/kg body weight/day, respectively. All tested animals were subsequently allowed free access to normal food and water. Each dose group was further divided into five duration subgroups of five rats each, in which the f...

A cross-sectional study was conducted in a randomly selected factory producing Portland cement in eastern Saudi Arabia to determine the prevalence of respiratory symptoms and diseases and chest x-ray changes consistent with pneumoconiosis in the employees. A sample of 150 exposed and 355 unexposed employees was selected. A questionnaire about respiratory symptoms was completed during an interview. Chest x-rays were read according to the ILO criteria for pneumoconiosis. Dust level was determined by the gravimetric method. Concentrations of personal respirable dust ranged from 2.13 mg/m3 in the kilns to 59.52 mg/m3 in the quarry area. Cough and phlegm were found to be related to cigarette smoking, while wheezing, shortness of breath, and bronchial asthma were related to dust levels. It is recommended that engineering measures be adopted to reduce the dust level in this company, together with health monitoring of exposed employees.

To determine the effect of chronic exposure to ammonia on pulmonary function among ammonia workers, 77 workers were randomly selected from an ammonia factory in the Eastern Province of Saudi Arabia and 355 were selected as controls from the administrative staffs of four industrial groups in Eastern Province. Spirometry was carried out and FEV1, FVC, and FEV1/FVC% were calculated. The ammonia level in the working environment was determined spectrophotometrically. 30% of the air samples had ammonia concentrations that exceeded the threshold limit value. Significant reductions in FEV1 % predicted and FVC % predicted were observed in ammonia workers exposed to higher cumulative ammonia levels (above 50 mg/m3-years). FEV1% predicted and FEV1/FVC% were significantly lower in symptomatic than in asymptomatic workers in the exposed group. These findings may raise the possibility that exposure to a high cumulative ammonia level produces a combined restrictive/obstructive ventilatory defect.

This cross-sectional study was conducted in 1992 in the oldest of three Portland cement producing factories in Eastern Saudi Arabia. The respirable dust level was in excess of the recommended ACGIH level in all sections. Spirometry was done for 149 cement workers and 348 controls, using a Vitalograph spirometer. FEV1, FVC, FEV1/FVC% and FEF25-75% were calculated and corrected to BTPS. A significantly higher post-shift reduction FEV1, FEV1/FVC% and FEF25-75% was observed in the exposed subjects. Multiple regression analysis showed a significant relationship between post-shift changes and exposure to cement dust but failed to support any relationship with smoking. These findings may indicate an increase in the bronchial muscle tone leading to some degree of bronchoconstriction as a result of an irritant effect induced by the acute exposure to cement dust.

The Department of Physiology at the College of Medicine and Medical Sciences, King Faisal University (KFU) had serious concerns about the effectiveness of the practical classes in motivating student learning and in achieving the objectives of these practicals. A new form of evaluation, the objective structured practical examination (OSPE) was introduced in June 1987. At KFU, the introduction of OSPE has led to a marked improvement in the mean scores for the laboratory component of the final examinations in the physiology courses. Such an improvement was not consistently observed in the other components of the examinations. Performance in stations evaluating skills was in general better than in those testing analytical and interpretive abilities. Female students performed significantly better in OSPE than male students in 4/5 and 3/5 physiology I and II examinations. Such gender differences were not observed in the written examinations.