Showing papers by "King Saud University published in 1991"

Pharmacological studies on aerial parts of Calotropis procera.

Abstract: The decoction of the aerial part of Calotropis procera is commonly used in Saudi Arabian traditional medicine for the treatment of variety of diseases including fever, joint pain, muscular spasm and constipation. The present investigation was undertaken to confirm its claimed activity in traditional medicine. The ethanol extract of the plant was tested on laboratory animals for its antipyretic, analgesic, anti-inflammatory, antibacterial, purgative and muscle relaxant activities. The results of this study showed a significant antipyretic, analgesic and neuromuscular blocking activity. On smooth muscle of guinea pig ileum, the extract produced contractions which was blocked by atropine supporting its use in constipation. The extract failed to produce significant anti-inflammatory and antibacterial activities. Our phytochemical studies on the aerial parts of C. procera showed the presence of alkaloids, cardiac glycosides, tannins, flavonoids, sterols and/or triterpenes. However, the chemical constituents responsible for the pharmacological activities remains to be investigated. The safety evaluation studies revealed that the use of extract in single high doses (up to 3g/kg) does not produce any visible toxic symptoms or mortality. However, prolong treatment (90 days) causes significantly higher mortality as compared to control group.

Recommended Health-based Limits in Occupational Exposure

Abstract: Assessment of air contamination in occupations resulted in the foundation by the World Health Organization of tables titles «Recommended health-based limits in occupational exposure». Special consideration in these tables is given to the mode of action of the injurious substances in the body, the system or organ prone to be affected, the degree of accumulation of the toxic substance in the body and the rate of excretion

Khat and oral cancer

Abstract: Oral cancers in the Asir region of Saudi Arabia have been observed to occur mostly among patients who have been long-term khat users. In a survey that reviewed cancers for the past two years there were 28 head and neck cancer patients, 10 of whom presented with a history of having chewed khat. One of these was a case of metastatic cervical lymph node and unknown primary, one was a parotid tumour, and the remaining eight presented with oral cancers. All were non-smoking khat chewers and all of them had used it over a period of 25 years or longer. We conclude that this strong correlation between khat chewing and oral cancer warrants attention.

Morphometric changes in the heights and anteroposterior diameters of the lumbar intervertebral discs with age.

Abstract: Changes in the heights and anteroposterior diameters of human lumbar intervertebral discs have been studied by means of measurements from radiographs. The results confirm previous reports that there is overall increase in the various dimensions of the disc with age. Growth of the discs apparently does not follow a linear pattern. There are alternating periods of overgrowth and thinning. After the 5th decade of life there is an appreciable decline of disc height. The significance of the findings is discussed.

Survey of quality of used frying oils from restaurants

Abstract: Commercial frying practices and frying conditions at 62 restaurants or fast-food outlets were investigated and the quality of their discarded frying oils was evaluated by several standard laboratory methods: total polar components (TPC), free fatty acids (%FFA), p-anisidine and peroxide values, color, viscosity, C18:2/C16:0, absorbance at 232 and 268 nm, and five quick test methods (Foodoil sensor, Oxifrit (RAU-Test), Fritest, Veri-Fry-TAM 150, and Veri-Fry-FFA 500). Frying techniques varied from primitive traditional practice at traditional shops to modern sophisticated frying procedures at some franchise restaurants. Discarded oils appeared to be heat-damaged to a varying extent according to the degree of quality control applied by the corresponding restaurants. Test methods were shown to possess different statistical correlations. Highly significant correlations were found between TPC and Foodoil sensor (c.f=0.93) and between Oxifrit and Fritest (c.f=0.94), each of which were also correlated relatively well to the TPC. Peroxide value followed by %FFA did not significantly (p<0.05) correlate with the TPC. Significant linear relationships (p⊕0.05) were found between the TPC and each of the other indicators but %FFA and peroxide value.

Inhibitory effect of natural honey on Helicobacter pylori.

Abstract: Honey is widely used in folk-medicine throughout the world. However, it has a limited use in modern medicine due to lack of scientific support. Based on some recent reports, an in vitro study was undertaken to evaluate its antibacterial activity on Helicobacter pylori and a few other pathogenic organisms. All isolates of H. pylori were inhibited by 20 per cent of honey. Most of the other bacteria examined (including both Gram-positive and Gram-negative) were also inhibited at concentrations of 20 per cent of honey; and half of them were inhibited by 10 per cent of honey. Furthermore, it was observed that some isolates were resistant to various antimicrobial agents but honey inhibited these organisms and the sensitive ones equally. Our study advocates carrying out clinical investigation of the effect of honey on gastroduodenal disorders colonised by H. pylori.

Parental smoking and the risk of childhood asthma.

Abstract: In order to explore the correlation between parents' smoking habits and bronchial asthma in children, we undertook a cross-sectional study of 3300 (54% males, 46% females) school children aged 7-12 years old. A survey of smoking habits and attitudes conducted in Saudi Arabia showed a positive correlation between parental smoking and asthma. This study showed a significant link between parental smoking and chest wheeze or whistling, cough, and family history of rhinitis. Evidence is accumulating that there is a relationship between parental smoking and respiratory symptoms in Saudi children. The present study results are clear evidence of a definite association between smoking in the home and bronchial asthma in young children, which not only may present immediate problems, but may also be a cause of illness in the future.

Isolation and characterization of two antimicrobial agents from mace (Myristica fragrans).

Abstract: The two antimicrobial resorcinols malabaricone B [1] and malabaricone C [2] were isolated from mace, the dried seed covers of Myristica fragrans. Both compounds exhibited strong antifungal and antibacterial activities. Structure modifications by methylation or reduction resulted in diminished activity.

The Interval Eigenvalue Problem

Abstract: Characterization of the set of eigen values of a general interval matrix A I is introduced and criteria on the eigenpair (λ,x) of Ax=λx, A∈A I , are given. Upper and lower bounds of the eigenvalues are therefore found. In order to avoid cumbersome manipulations, the symmetric case is introduced first with the results generalized later on

Secular Sea-Level Change

Abstract: Sea-level change as recorded by tide gauges exhibits a complex spatial and temporal variability for a number of reasons, including tectonic movements of changes in ocean volume and the adjustment of the crust to major Late Pleistocene deglaciation, and to recent mountain glacier melting. Tide gaude records have been analysed by least squares regression for secular trends and mean regional trends have been estimated for 10° × 10° areas. These have been expanded into a surface spherical harmonic series, yielding the global long wavelength pattern of sea-level change. The low degree terms in this expansion represent a combination of tectonic change and local or regional changes in sea-level. The eustatic rise, reflecting a change in water volume and corresponding to the zero degree harmonic, is estimated as 1.15 ± 0.38 mm/year. The first degree terms in the expansion are negligibly small, indicating that there is no significant shift in the centre of mass of the ocean relative to the solid Earth. Of the second degree terms only the zonal coefficient is significant with an equatorial sea-level rise and a polar sea-level drop. The contributions from recent changes in mountain glacier volumes and postglacial rebound to the spatial variability are significant but not for the very low degree terms. The separation of these contributions from the observed change yields a globally averaged secular steric change of about 0.5 mm/year but the uncertainties are large. The mainly zonal geometry of the steric change implies greater thermal expansion effects in low latitudes than in high latitudes.

Analysis of possible factors influencing the occurrence of occlusal tooth wear in a young Saudi population.

Abstract: The purpose of this study was to attempt to correlate possible etiologic factors with the occurrence of occlusal tooth wear in a young Saudi population. The material comprised 90 individuals with a mean age of 22 years within a range of 19–25 years. A dentition wear index, in addition to anterior and posterior wear subindices were derived from tooth-by-tooth evaluations of casts. Factors found to correlate significantly with increased occlusal wear were bruxism, biting habits such as pen- and nail-biting, use of an indigenous chewing-stick called miswak, and high intake of fruit juices. There was no correlation between subjects from differing geographic and/or climatic habitats and the severity of tooth wear. The common element of a harsh desert terrain may constitute the dominant passive abrasive etiologic factor in the present sample.

Multimode and multiphoton processes in a non-linear Jaynes-Cummings model

Abstract: Exact operator solutions for the generalized Jaynes-Cummings model (JCM) of a two-level atom interacting with a non-linear bosonic field with multimodes has been given. Two different methods have been applied, the Heisenberg equations and the evolution operator. The photon numbers have been given through the characteristic function. Different statistical quantities have been computed. The phenomenon of collapses and revivals in the atomic inversion and the photon number as well as squeezing have been investigated.

Rethinking Communicative Language Teaching: Reflection and the EFL Classroom

Abstract: The contention of this paper is that many activities in the communicative language teaching (CLT) classroom discourage reflection or contemplation. The first part of this paper analyzes the prominence in CLT of phenomenalistic and intuitive activities which, with their emphases on conspicuous action and spontaneous response, suggest a proclivity to a nonreflective view of language acquisition. The second part, making use of what philosophers and psychologists have concluded about reflection, examines when, how, and why a person reflects. The last part of the paper discusses three types of CLT activities which could encourage reflection: task-oriented, process-oriented, and synthesis-oriented. The conclusion is that more activities centered around reflective thinking should be incorporated in ESL/EFL classrooms to supplement the valuable phenomenally and intuitively oriented activities.

Prognostic factors in the conservative treatment of ureteric stones.

Abstract: A prospective study was made of 125 ureteric stones in order to detect factors which would predict the successful outcome of conservative treatment. The factors studied were the duration of pain prior to presentation, pyuria, haematuria, surface regularity of the stone and the degree of obstruction as seen radiologically. In stones less than or equal to 10 mm in size, conservative treatment was successful when the duration of pain was less than 30 days (39/45), when there was no significant pyuria (53/82), when the stones had an irregular surface (44/65) and when obstruction was only partial (55/88). Since most of these factors were interactive, further statistical analysis showed that duration of pain was the only significant factor in predicting the outcome of conservative treatment. In stones greater than 10 mm in size these factors had no predictive value and only 2/23 were passed spontaneously on conservative treatment.

Investigation of diuretic drug plants. 1. Phytochemical screening and pharmacological evaluation of Anethum graveolens L., Apium graveolens L., Daucus carota L. and Eruca sativa Mill

Abstract: A preliminary phytochemical screening of fruits of Anethum graveolens L., Apium graveolens L., Daucus carota L., and seeds of Eruca sativa Mill., revealed the presence of volatile oil, sterols and/or triterpenes, carbohydrates and/or glycosides, tannins and flavonoids in the four entitled plants; Glucosinolates were detected only in Eruca seeds. Pharmacological evaluation of the aforementioned plants for diuretic activity has shown the ethanolic extracts of Eruca sativa seeds and fruits of Anethum graveolens, Daucus carota as well as the volatile oils in the former two plants to produce an increase in urine flow in dogs. Volatile oil of Eruca seeds, significantly, increased Na+, K+ and Cl− excretion in urine, whereas Anethum graveolens volatile oil significantly increased Na+ and Cl− excretion only.

Hepatitis C virus antibodies in high-risk Saudi groups.

Abstract: Non-A non-B hepatitis recently renamed as hepatitis C virus (HCV) accounts for over 90% of hepatitis cases worldwide associated with blood transfusions. Application of a recombinant-based enzyme immunoassay for the detection of antibodies to HCV to a sample of 500 male Saudi blood donors and 260 healthy Saudi pregnant women indicated that HVC is endemic in the Saudi population. Anti-HCV was detected in 28 (5.6%) of the blood donors and 12 (4.6%) of the pregnant women for an overall frequency of 5.3% in healthy Saudi adults who had never received blood transfusions. This rate is at least 5 times higher than that reported for the US and Western Europe. Also assessed was the HCV rate in subsamples of Saudis considered at risk of this infection. Here anti-HCV was detected in 22 (78.6%) hemophiliacs 26 (33.3%) patients with thalassemia and sickle cell disease 17 (26.1%) hemodialysis patients with renal failure and 35 (15.9%) individuals with a sexually transmitted disease. The prevalence of anti-HBc ranged from 28% in blood donors to 46% in hemophiliacs. The significantly higher prevalence of HCV in patients with sexually transmitted diseases than in blood donors suggests that this disease is transmitted through heterosexual contact as well as blood transfusions. Given the high baseline level of HCV infection in the Saudi population and the possibility of serious sequelae (e.g. chronic active hepatitis cirrhosis and hepatocellular carcinoma) routine anti-HCV screening of blood donations is urged.

Environmental impact of seawater desalination plants.

Abstract: Enormous amounts of seawater are desalted everyday worldwide. The total world production of fresh water from the sea is about 2621 mgd (9.92 million m(3) day(-1) 1985 figures). Desalting processes are normally associated with the rejection of high concentration waste brine from the plant itself or from the pretreatment units as well as during the cleaning period. In thermal processes, mainly multistage flash (MSF) thermal pollution occurs. These pollutants increase the seawater temperature, salinity, water current and turbidity. They also harm the marine environment, causing fish to migrate while enhancing the presence of algae, nematods and tiny molluscus. Sometimes micro-elements and toxic materials appear in the discharged brine.This paper will discuss the impact of the effluents from the desalination plants on the seawater environment with particular reference to the Saudi desalination plants, since they account for about 50% of the world desalination capacity.

Corneal dystrophies among patients undergoing keratoplasty in Saudi Arabia.

Abstract: Diseases leading to corneal opacities are inflammations, infections, metabolic causes, trauma, or genetically determined diseases. Corneal dystrophies may lead to corneal blindness. A clinical and pathological review of 2,108 corneal specimens received from December 1983 to January 1988 revealed 86 (4%) corneal specimens with corneal dystrophies. Fifty-three (62%) patients had macular dystrophy, 11 (13%) had congenital hereditary endothelial dystrophy (CHED), 12 (14%) had Fuchs' corneal dystrophy, 5 (6%) had lattice corneal dystrophy, and 3 (4%) had granular dystrophy. Macular dystrophy appears to be the most common cause of corneal dystrophy in Saudi Arabia. Twenty-two (42%) patients with macular dystrophy and 10 (91%) patients with CHED were the result of consanguineous marriages. Genetic counseling is advisable among families who carry the trait of CHED or macular corneal dystrophy.

Pattern of cancer at Asir Central Hospital, Abha, Saudi Arabia.

Abstract: Six hundred ninety-seven histologically confirmed cases of cancer were seen in the three-year period, 1987 to 1989, at Asir Central Hospital in Abha, Saudi Arabia. Percentage (crude relative) frequ...