Modulation of immunological responses by aqueous extract of Datura stramonium L. seeds on cyclophosphamide-induced immunosuppression in Wistar rats.

BACKGROUND: Datura stramonium L. (Solanaceae) is used traditionally in west Africa to treat asthma, epilepsy, rheumatoid arthritis, filariasis microbial infections and conjunctivitis. This study investigated the immunomodulatory effects of aqueous seed extract of D. stramonium L. (ASEDS) on Wistar rats. METHODS: Thirty Wistar albino rats (180-200 g) were randomized into 6 groups (n = 5). Group 1 received distilled water only. Rats in groups 2-6 were pretreated with 10 mg/kg body weight (b.w.) Cyclophosphamide orally for 27-days to induce immunosuppression. Thereafter, they received treatment orally for 28 days as follows: Group 2 (distilled water), group 3 (5 mg/kg b.w. Levamisole), groups 4-6 (60, 90 and 120 mg/kg b.w. ASEDS, respectively). HPLC was used to determine major compounds in ASEDS. The effects of ASEDS on immune cells, immunoglobulins A, G and M levels, lipoproteins, and antioxidant status of rats were evaluated. RESULTS: ASEDS indicated high content of Acutumine, Quinine, Catechin, Chlorogenic acid, Gallic acid, Quercetin, Vanillic acid, Luteolin, Formosanin C, Saponin, Cyanidin, Tannic acid, 3-Carene, Limonene and α-terpineol. Cyclophosphamide triggered significant (p < 0.05) reduction in total leucocyte count and differentials, IgA, IgG, high-density lipoproteins (HDL), catalase, superoxide dismutase, glutathione peroxidase, vitamins A, C and E levels of untreated rats. Administration of ASEDS led to significant (p < 0.05) improvement in immune cell counts, immunoglobulin synthesis, high-density lipoprotein concentration, and antioxidant status of rats in the treated groups. CONCLUSIONS: The results obtained from the study showed the immunomodulatory activity of ASEDS, thereby indicating its potential in immunostimulatory drug discovery.

Effects of quinine on gastric ulcer healing in Wistar rats.

Background Quinine (QT) is an important anti-malarial drug; however, there is little information about its effects on the gut. Therefore, this study aimed to investigate the effects of a therapeutic dose of QT on the healing of gastric ulcer in rats. Methods Male Wistar rats weighing 150-200 g were divided into three groups: control rats without ulcer (group 1), ulcerated rats treated with 1 mL/kg (p.o.) normal saline (NS) (group 2), and ulcerated rats treated with 10 mg/kg (p.o.) QT (group 3). Ulcers were induced by serosal application of 80 % acetic acid to the stomach of rats anaesthetized with 50 mg/kg thiopentone sodium and treatment was given three times daily. Healing was assessed on days 3, 7 and 10 after ulcer induction by macroscopic measurement of: ulcer area, histology, lipid peroxidation, superoxide dismutase activity and gastric mucus secretion. Results At day 3, there was no significant difference (p>0.05) in ulcer areas between NS- and QT-treated rats. By day 10, however, the percentage area healed in NS treated (59.6±2.35 %) was significantly higher (p<0.05) than in QT rats (49.0±2.20 %) and clearing of inflammatory cells and re-epithelization was greater in NS-treated group. By days 7 and 10, lipid peroxidation was significantly higher in QT animals, when compared with NS-treated rats and controls (p<0.05). Superoxide dismutase activity and mucus secretion were significantly (p<0.05) higher in NS-treated than QT-treated rats. Conclusions QT delayed ulcer healing by prolonging the inflammatory phase of healing, increasing oxidative stress, reducing antioxidant activity and gastric mucus secretion.

Antidiarrheal activity of hexane extract of Citrus limon peel in an experimental animal model.

OBJECTIVE: Acute diarrhea is one of the major illnesses that cause death in children, despite clinical interventions and the use of oral rehydration therapy. Thus, there is need to discover other effective, affordable and accessible treatments for this disease. Therefore, this study was carried out to investigate the effects of hexane extract of Citrus limon peel (HECLP) on castor oil-induced diarrhea in rats. METHODS: Diarrhea was induced in male albino Wistar rats weighing 100-150 g. The antidiarrheal activity of HECLP at different oral dosages (5, 10 and 20 mg/kg) was investigated by counting the number of wet fecal pellets. Animals were further treated with propranolol, prazosin, nifedipine and atropine to assess the effects of receptor blockers on the activities of the extract. The effects of HECLP on castor oil-induced enteropooling and the intestinal transit time of activated charcoal were also evaluated. RESULTS: Each of the 3 doses of C. limon significantly reduced (P < 0.05) the number of wet fecal pellets produced by animals, with 20 mg/kg HECLP producing the highest percentage inhibition (34.2%). Wet fecal pellet inhibition by the standard drug loperamide (3 mg/kg p.o.) was 68.4% relative to the negative control. Blockage of ß adrenergic receptors by propanolol abolished the antidiarrheal effects of HECLP. Intestinal fluid accumulation was inhibited by 68.7% and 78.5% by 20 mg/kg HECLP and loperamide respectively. Furthermore, 20 mg/kg HECLP significantly (P < 0.05) reduced the percentage intestinal transit time (21.4% ± 1.42%), relative to the control (34.2% ± 4.29%); atropine (5 mg/kg, intraperitoneal injection) significantly (P < 0.001) reduced the percentage intestinal transit time to 11.2% ± 0.85%. CONCLUSION: These results suggest that C. limon peel possesses antidiarrheal effects through antisecretory and antimotility mechanisms that act through the ß adrenergic system.

The impact of various assessment parameters on medical students' performance in first professional examination in physiology.

BACKGROUND: This study was carried out to assess the relationship between thevarious assessment parameters, viz. continuous assessment (CA), multiple choice questions (MCQ), essay, practical, oral with the overall performance in the first professional examination in Physiology. MATERIALS AND METHODS: The results of all 244 students that sat for the examination over 4 years were used. The CA, MCQ, essay, practical, oral and overall performance scores were obtained. All the scores were rounded up to 100% to give each parameter equal weighting. RESULTS: Analysis showed that the average overall performance was 50.8 ± 5.3. The best average performance was in practical (55.5 ± 9.1), while the least was in MCQ (44.1 ± 7.8). In the study, 81.1% of students passed orals, 80.3% passed practical, 72.5% passed CA, 58.6% passed essay, 22.5% passed MCQ and 71.7% of students passed on the overall performance. All assessment parameters significantly correlated with overall performance. Continuous assessment had the best correlation (r = 0.801, P = 0.000), while oral had the least correlation (r = 0.277, P = 0.000) with overall performance. Essay was the best predictor of overall performance (ß = 0.421, P = 000), followed by MCQ (ß = 0.356, P = 000), while practical was the least predictor of performance (ß = 0.162, P = 000). CONCLUSION: We suggest that the department should uphold the principle of continuous assessment and more effort be made in the design of MCQ so that performance can improve.