Increased systemic low-grade inflammation in high altitude native rats mediated by adrenergic receptors

To compare the serum levels of inflammatory mediators in high altitude [HA] native rats, and to search for the possible underlying mechanism[s]. The study was carried out between January and April 2013. Fifty male rats from the same genetic pool were bred at either a HA or low altitude [LA] area. The study was carried out in 2 stages. In the first stage, serum levels of inflammatory markers, adhesive molecules, lipid profiles, catecholamines, magnesium [Mg[+2]], and lipid peroxidation were compared between theses 2 groups. In the second stages, inflammatory response and lipid peroxidation were analyzed in HA native rats after treatment with either alpha [Prazosin] or beta [propranolol] adrenergic blockage. The HA native rats showed significant increases in the serum levels of inflammatory cytokines, lipid profiles, as well as a significant increase in the urinary norepinephrine with a concomitant decrease in the serum levels of Mg[+2] and increased lipid peroxidation. Blockage of the beta and alpha adrenergic receptors of the HA rats caused partial or complete decreases in both inflammatory and oxidative stress mediators. Living under HA conditions results in an increased systemic inflammatory reaction; an effect that is mediated through the sympathetic nervous system mainly via alpha-adrenergic receptors and could be attributed to low Mg[+2] levels

Chronic exposure of rats to native high altitude increases in blood pressure via activation of the renin-angiotensinaldosterone system

To study the effect of chronic exposure to native high altitude [HA] on blood pressure, and to investigate the underlying mechanism of action. This study was carried out between February and April 2011. A total of 20 male rats were divided into 2 groups [n=10 rats]. The low altitude [LA] group were rats born and lived in an LA environment at King Saud University, College of Pharmacy, Riyadh, Kingdom of Saudi Arabia [KSA], and the HA group were rats born in the same LA area, then acclimatized to HA area in Physiology Department, King Khalid University, College of Medicine, Abha, KSA for 90 days. At the end of day 90, hematocrit, plasma renin activity, aldosterone, norepinephrine and vasopressin levels were determined in both groups. Invasive arterial blood pressure was also measured, and fractional excretion of sodium [FENa], and potassium [FE[K]] were calculated. The quantitative real time-polymerase chain reaction of renin was carried out in the kidneys of both rat groups. When compared to LA native rats, HA rats exhibited a significant increase in systolic and diastolic blood pressure with a significant increase in renin plasma activity as well as an increase in the levels of aldosterone, norepinephrine, and vasopressin. Furthermore, HA rats showed a significant increase in renin expression in their kidneys, as well as decreased FENa. Data shows that prolonged exposure to HA results in elevated blood pressure precipitated by the activation of the renin-angiotensin-aldosterone system

Potential roles for vitamins E and C in combination in modulating exhaustive swimming and high altitude-associated lung injury in rats

To evaluate and compare the potential role of vitamins E and C in protecting against acute swimming induced lung damage at different altitudes. The study was carried out between January and March 2011. Eighteen male rats were bred and reared at either high altitude in Abha city or low altitude in Riyadh city, KSA. The rats were divided into 3 groups: 1] non-stress control, 2] forced swimming stressed, and 3] vitamin E and C pretreated stressed. At the end of the procedure, lung tissue levels of thiobarbituric acid reactive substances [TBARS], reduced glutathione [GSH], superoxide dismutase [SOD], and catalase [CAT] were determined. In control rats, the baseline levels of TBARS were significantly increased and the baseline levels of both GSH and SOD were significantly decreased in the lungs of animals at high altitude compared with those at low altitude. Acute forced swimming resulted a significant increase in TBARS levels and a significant decrease in activities of SOD and CAT in the lungs in both altitude areas, and resulted in a significant decrease in GSH levels at high altitude rats only as compared with the resting state. Supplementation of vitamins E and C in combination effectively ameliorated all the parameters measured at both altitudes. Our novel observations suggest that supplementation of vitamins E and C could be beneficial against exhaustive swimming- and high altitude-associated lung injury

Inhibited thyroid function, impaired lipid metabolism and increased tissue oxidative stress in rats native to high altitude

To evaluate the effect of high altitude on markers of thyroid function, serum lipid profile and tissues oxidative stress in male Wistar rats native to high altitude [HA] with male rats native to low altitude [LA]. Randomized experimental animal study. Physiology laboratory, Medical School of King Khalid University. Male rats aged six months, weighing 250 gm were bred and maintained at low altitude [LA, 600 m above sea level, n=6] or high altitude [HA, 2800 m, n=6], under the same laboratory conditions and fed the same diet. Blood samples were obtained for thyroid hormones and lipid profile analysis. Livers, kidneys, lungs and testes were collected and used for determination levels of thiobarbituric acid reactive substances [TBARS], reduced glutathione [GSH], Superoxide Dismutase [SOD] and Catalase Activity [CAT]. HA rats had significantly [P<0.05] lower serum T3 [17.14%], T4 [13.75%], TSH [39.29%] and total cholesterol [15.84%] and LDL [60.90%].There were no significant differences in TAG or HDL. All tissues from HA rats showed significant decreases in SOD and CAT activities compared to LA rats. These rats showed significantly higher oxidative stress in the lungs and the liver, but lower oxidative stress in the kidney and no difference in the testes. Living at high altitude environment results in impaired thyroid function and lipid metabolism and causes increased tissue oxidative stress

Acute oral administration of Khat [Catha edulis] aqueous extract elevates blood pressure and prolongs QT and QTC intervals in Wistar albino rats

To investigate the effect of Khat [Catha edulis] acute administration on blood pressure [BP] and electrocardiogram [ECG] in vivo. This study was performed between January and February 2009 at the Physiology Laboratory, Medical College of King Khalid University, Abha, Kingdom of Saudi Arabia. Two groups of Wistar rats [n=10], weighing 190-200 g were divided into control group and Khat treated group. Throughout the study, arterial BP and ECG were recorded for 60 consecutive minutes. The data were collected and analyzed by Power Lab Data Acquisition System every 10 minutes, and were compared within and between the groups. Oral administration of Khat resulted in significant time dependent increases in both systolic and diastolic BP with a maximum increase at minute 60 after extract administration [systolic BP - 34.1%; and diastolic BP - 46.2%]. Heart rate was significantly increased at all minutes of the study with a maximum increase occurring at minute 40 [12.8%]. There was a significant decrease in PR interval through the experiment, and the maximum decrease was observed at minute 40 [-15.2%]. However, QT and QTc started to widen 20 minutes after extract administration with a maximum prolongation in both intervals to occur at minute 40 [QT - 11.6%; QTc - 9.1%]. These newly reported changes in the ECG of rats after Khat administration should be a warning regarding the cardiac hazards of Khat chewing

Khat [Catha edulis]extract increases oxidative stress parameters and impairs renal and hepatic functions in rats

The habit of khat chewing represents a major socio-economic problem in many countries but research into its hepato-renal toxic effects has produced contradictory results. To evaluate the subacute effects of Khat [Catha edulis] extract on hepatic and renal functions in white albino rats. Randomized experimental animal study. Physiology laboratory, medical school of King Khalid University. Twenty white albino rats aged between 14 and 16 weeks were included in the study. The rats were assigned randomly into two groups, ten each. Treated rats received orally administered hydro-ethanol extract of Catha edulis for four weeks. Control rats received corresponding amounts of normal saline. There was statistically significant increase in the activities of hepatic enzymes in treated rats compared to the control group. In addition, serum urea, bilirubin and phosphorus concentrations were significantly increased compared to a decreased serum total protein and albumin concentrations. Oral administration of the extract induced lipid peroxidation and oxidative stress in hepatic and renal tissues as shown by significant increases in lipid peroxidation biomarkers thiobarbituric acid reactive substances [TBARS] and significant decreases in levels of superoxide dismutase [SOD], catalase [CAT] and glutathione [GSH]. Histological examination of Catha edulis treated rats revealed marked hepato-renal pathological changes compared to the control group. These results indicate that orally administered Catha edulis extract exerts severe hepato-nephro toxicity and the mechanism of this damage may be related to oxidation, increased lipid peroxidation, and generation of free radicals inside these tissues

Gastroprotective effects of aqueous extract of Chamomilla recutita against ethanol-induced gastric ulcers

To investigate the gastroprotective effects of an orally administered aqueous extract of Chamomilla recutitia [ACE] against ethanol-induced gastric ulcers in male Wistar rats. This study was performed during January and February 2009, in the Research Labs in the Department of Physiology at the Medical School, King Khalid University, Abha, Kingdom of Saudi Arabia. Sixty white albino rats were divided into 5 groups. Group 1 [control group] was treated with deionized water for 28 days; animals in group 2 to group 5 received zero, 0.5, 1, or 2 gm/kg ACE fro 27 days. Stomach ulcerations were induced by orally administering a single dose of 70% ethanol on day 28. Lesions in the gastric mucosa were examined macroscopically to calculate the ulcer index [UI] and estimated glutathione [GSH] for each animal. Compared to non-ACE treated rats, the UI decreased significantly in a dose-dependent manner in treated animals. Furthermore, GSH levels fell significantly after ethanol treatment; this decrease was prevented by ACE treatment. However, daily treatment of rats with the maximum ACE dose actually led to an increase in GSH levels. Histological examination revealed that ACE treatment alleviated, or completely resolved ethanol-induced degenerative alterations, including disorganization of cell nuclei and gland morphology with erosion in the gastric mucosa and interrupted muscularis mucosa. This study provides evidence for the regulation of ACE-mediated gastroprotection against ethanol-induced ulceration by GSH

In vivo acute effects of orally administered hydro-ethanol extract of catha edulis on blood glucose levels in normal, glucose-fed hyperglycemic, and alloxan-induced diabetic rats

To investigate the blood glucose lowering effect of khat [Catha edulis] extract in normal, glucose-loaded, and alloxan diabetic rats. Three experimental protocols were used in this study. In each of the first 2 protocols, 3 groups of rats [6 rats per group] were used as control group [NS], Catha edulis [CE] treated, and glibenclamide treated groups. This study was carried out at the Physiological Laboratory of the Medical School of King Khalid University, Abha, Saudi Arabia between October and November, 2009. Normal rats were used in the first protocol while alloxan diabetic rats were used in the second protocol. Blood glucose levels were measured in all 3 groups after single dose injections of saline, CE or glibenclamide. In the third protocol, another 6 groups of rats [6 rats per group] were prepared as in the first 2 protocols and oral glucose tolerance test [OGTT] was performed on each rat after oral administration of glucose [1.5g/kg]. Oral administration of a hydro-ethanol extract of CE caused no statistically significant change in blood glucose levels in normal rats with or without glucose loading. There were slight, non significant increases in blood glucose levels of extract-treated diabetic rats, with and without glucose loading, as compared to the corresponding untreated rats. Oral administration of CE extract does not exert a hypoglycemic effect in normal, glucose-loaded, and diabetic rats

prevalence of malnutrition among high and low altitude preschool children of southwestern Saudi Arabia

To assess the current status of protein energy malnutrition [PEM] in the high and low altitude preschool children aged 12-71 months. A cross-sectional study conducted during the year of 2003 and involved 572 and 469 preschool children of Southwestern Saudi Arabia born and living permanently at high and low altitude areas. Anthropometric measurements were carried out to assess the prevalence of PEM using 3 indicators such as underweight, wasting and stunting following World Health Organization standards. Prevalence differences were examined by age, gender, altitude, and parental socioeconomic status. The prevalence of the 3 types of PEM was significantly higher at low altitude than at high altitude and significantly higher among children born to illiterate than to educated parents. Older children were more underweight and stunted than younger children and underweight and wasting were significantly more common in boys than girls. Annual family income per person was negatively and significantly associated with underweight and stunting, but not with wasting. Multivariate analysis showed that after controlling for all sociobiological factors, low altitude remained a strong risk factor. The difference in PEM between high and low altitude preschool children could be related to the milder environmental conditions at high altitude and the higher incidence of tropical infections in lowland children. Future studies are required to verify these speculations, and to establish programs to control and prevent PEM in preschool children at low altitude

effect of long-term use of computer mouse devices on median nerve entrapment

To assess the effect of long-term use of computer mouse devices on the median nerves. A cross-section prospective study conducted during the year 2004 involved 41 male secretaries employed in the Health Colleges of King Khalid University in Abha, Kingdom of Saudi Arabia. A questionnaire describing sociodemographic and computer use was completed. The electrophysiological study included measurements of motor latencies, motor conduction velocities, and amplitudes of compound muscle action potential of the right median nerve and compared these with those of the left median nerve [control]. All of our subjects were right handed. Terminal latency index [TLI] was calculated for each nerve tested. Entrapment neuropathy of the median nerve at the wrist was defined as TLI <0.30. The mean TLI of the median nerve in the right hand was significantly lower than that in the left hand. Eight of the 23 asymptomatic participants [34.8%], 6 of the 12 who reported hand discomfort [50%], and all the 6 participants who met clinical criteria for carpal tunnel syndrome showed electrophysiological evidence suggestive of right median nerve entrapment neuropathy at the wrist. Test of association showed a negative and significant correlation between TLI of the right median nerve and weekly hours mouse device use while no significant correlation was found between TLI in the same hand and weekly hours keyboard use. Frequent computer mouse device users are at high risk of developing median nerve entrapment neuropathy at the wrist

Is it necessary to consider obesity when constructing norms for hemoglobin or when screening for anemia using hemoglobin levels?

To assess the relationship of total adiposity and abdominal adiposity on hemoglobin levels in Saudi nonpregnant women. We carried out this cross-sectional study during winter of 2002 [from January to March] in and around Abha city, Kingdom of Saudi Arabia. Included in the study were 530 non-pregnant women between the age of 18-65 years. Body weight was measured using an Avery Beam weighing scale, while height was measured using a stadiometer and waist circumference using a fiberglass. Hemoglobin levels were estimated using cyanmethemoglobin method. Total obesity was defined as body mass index [BMI] >/= 30 and abdominal obesity as WC >88 cm. The mean and median hemoglobin levels were significantly higher in abdominally obese women compared with totally obese [p<0.04 versus <0.02] and non obese ones [p<0.04 versus <0.03]. No significant differences in the mean and median hemoglobin levels were observed when abdominally obese women were compared with both abdominally and totally obese ones [p<0.7 for both]. The mean and the median hemoglobin levels were virtually identical in non-obese and totally obese women. Statistical analysis showed that the mean hemoglobin level was positively and significantly associated with WC [p<0.005] and negatively and insignificantly associated with BMI [p<0.8]. In view of the positive and significant association between abdominal obesity and the mean hemoglobin level in this population, abdominal obesity should be considered when constructing norms for hemoglobin or when screening for anemia using hemoglobin levels

relationship of body weight to altitude in preschool children of southwestern Saudi Arabia

To determine the average weight and height and the prevalence of overweight or obesity and thinness in preschool children of the Southwestern highlands of the Kingdom of Saudi Arabia and compare them with their counterparts living at lower altitudes. A cross-sectional study of 559 preschool children aged 12-71 months born and living permanently at high altitude, and 463 preschool children of comparable age born and living permanently at low altitude. For each child at high and low altitude, age was recorded and weight and height were measured. Weight for height Z-score with WHO standards was used for an assessment of normal weight, overweight or obesity and thinness. The highland preschool children were found to be significantly heavier and taller than their counterparts living at low altitude, 92.1% of all highland preschool children and 67.6% of lowland preschool children were found to have normal weight [p < 0.0001], Overweight or obesity was insignificantly greater among preschool children of the highlands [2.3%] compared to the preschool children of the low lying areas [0.9%] [p<0.7]. Thinness was significantly more prevalent among preschool children of the lowlands [31.5%] than preschool children of the highlands [5.5%] [p< 0.0001]. At both high and low altitude, there were no significant differences in the prevalence of overweight or obesity and thinness between boys and girls. The findings of this study indicate that thinness is a major nutritional problem among lowland preschool children. This may be attributed to the prevailing tropical environmental conditions on the health of children at low altitude

Pattern of haemoglobin among high and low altitude children of southwestern Saudi Arabia

To determine the levels of haemoglobin and to study some of its correlates in high and low altitude children of the Southwestern region of the kingdom of Saudi Arabia. A cross-sectional study of 1331 Saudi children aged 1-15 years born and living permanently at high altitude [2800-3150 m above sea level] and 1185 Saudi children of comparable age born and living permanently at low altitude [500 m above sea level] was conducted. Their haemoglobin levels were estimated by using cyanmethaemoglobin method and correlated with age, weight and height. The mean haemoglobin levels were significantly greater in highland children compared with lowland children [p<0.0001 for both boys and girls]. There were no significant differences in the mean haemoglobin levels between boys and girls at each study site. In both high and lowland children haemoglobin levels rose with age although lowland girls showed a drop beyond the age of 11-13 years and highland girls did not show any increase beyond the age of 9-11 years. In both boys and girls haemoglobin was found to be positively and significantly correlated with weight and height. The difference in haemoglobin levels between high and lowland children was attributed to the combined effect of high altitude hypoxia and the higher incidence of tropical infections among lowland children