Bioavailability of α-tocopherol stereoisomers in lambs depends on dietary doses of all-rac- or RRR-α-tocopheryl acetate.

When supplementing lamb diets with vitamin E, an equivalence factor of 1.36 is used to discriminate between RRR-α-tocopheryl acetate and all-rac-α-tocopheryl acetate. However, more recent studies suggest a need for new equivalence factors for livestock animals. The current study aimed to determine the effect of RRR- and all-rac-α-tocopheryl acetate supplementation on α-tocopherol deposition in lamb tissues. A total of 108 Rasa Aragonesa breed lambs were fed increasing amounts of all-rac-α-tocopheryl acetate (0.25, 0.5, 1.0 and 2.0 g/kg compound feed) or RRR-α-tocopheryl acetate (0.125, 0.25, 0.5 and 1.0 g/kg compound feed) by adding them to a basal diet that contained 0.025 g/kg feed of all-rac-α-tocopheryl acetate as part of the standard vitamin and mineral mixture. The diets were fed for the last 14 days before slaughtering at 25.8±1.67 kg BW. Within 20 min after slaughter samples of muscle, heart, liver, brain and spleen were frozen at -20°C until α-tocopherol analysis. Increased supplementation of either vitamin E sources led to a significant increase (P < 0.001) in α-tocopherol concentration in all tissues studied. The tissue with the highest α-tocopherol concentration was the liver followed by spleen, heart and muscle. At similar supplementation levels (0.25, 0.50 and 1.0 g/kg compound feed), α-tocopherol content in the selected tissues was not affected by α-tocopherol source. However, the ratios between RRR- and all-rac-α-tocopheryl acetate increased with the increasing α-tocopherol supplementation (at 0.25 and 1.0 g/kg compound feed), from 1.06 to 1.16 in muscle, 1.07 to 1.15 in heart, 0.91 to 0.94 in liver and 0.98 to 1.10 in spleen. The highest relative proportion of Æ©2S (sum of SSS-, SSR-, SRS- and SRR-α-tocopherol)-configured stereoisomers was found in the liver of lambs supplemented with all-rac-α-tocopheryl acetate accounting for up to 35 to 39% of the total α-tocopherol retained, whereas the proportion of Æ©2S-configured stereoisomers in the other tissues accounted for <14%. Increasing all-rac-α-tocopheryl acetate supplementation was also found to affect the 2R-configured stereoisomer profile in muscle, heart and spleen with increasing proportions of RRS-, RSR- and RSS- at the cost of RRR-α-tocopherol. In all tissues, the relative proportion of all non-RRR-stereoisomers in lambs receiving RRR-α-tocopheryl acetate was lower than RRR-α-tocopherol. These results confirm that the relative bioavailability of RRR- and all-rac-α-tocopheryl acetate is dose- and tissue-dependent and that a single ratio to discriminate the two sources cannot be used.

Students' perceptions of their learning environment at the College of Medicine, University of Ilorin, Southwest, Nigeria.

BACKGROUND: Quality of medical school graduates is influenced by cumulative effect of their learning environment. Measurement of such environment at the University of Ilorin, Nigeria was done by evaluating Students' perception using the DREEM questionnaires, with a view to improving the quality of medical education. METHODS: DREEM questionnaire was applied to second, third, fourth and fifth year medical students, for assessment of the various aspects of effective educational environment. Responses were analyzed using SPSS software version 19. RESULTS: One hundred and eighty students (66.2%) were males and 92 (33.8%) females. The mean age was 21.2 years ± 2.5 with 83 (30.5%) students in second year of study, 68 (25.0%) in third year, 80 (29.4%) in fourth year and 41 (15.1%) in fifth year. Mean global perception score was 108.4 / 200 points (54.2%) and this was not affected by sex, age and year of study. Scores for "Students' Perception of Learning" (SPL) and "Students' Academic Self Perceptions" (SASP) were 28.0/48 (58.8%) and 21.8/32 (68.1%) respectively. Three key areas are in need of attention; "Students' Perception of Course Organizers" (SPCO) (22.0/44, 50.0%), "Students' Perception of Atmosphere" (SPA) (23.8/48, 49.6%) and "Students' Social Self Perceptions" (SSSP) (12.8/28, 45.7%). The SSSP score was significantly higher in males (13.18) than in females (12.06) (p=0.02; p < 0.05), and in second (13.38) and third year (13.55) students compared to fourth year (12.16) and fifth year (11.76) (p=0.003). CONCLUSION: Improvement in some aspect of teaching, atmosphere and social factors could be of further benefit to the students.

The clinical spectrum of lymphangiomas and lymphangiomatosis of the spleen.

Lymphangiomas of the spleen are infrequent neoplasms of the spleen with clinical manifestations ranging from insignificant incidental findings to large, symptomatic cystic masses requiring surgical intervention. An associated syndrome may be lymphangiomatosis, in which the lymphangiomatous process involves other sites or organs, such as the liver, spleen, axilla, and mediastinum. Vasoformative neoplasms (hemangioma, lymphangioma) are relatively uncommon tumors or hamartomas of the spleen. Although well reported in the literature, their surgical significance is not well recognized. These lesions present a broad spectrum of pathologic findings of varied surgical importance. As incidental findings, they may be mistakenly considered as a valid indication for splenectomy. On the contrary, more extensive involvement of the spleen may cause symptomatic splenomegaly, which is a valid indication for splenectomy. When the spleen is diffusely involved (lymphangiomatosis), it may be part of a syndrome of generalized lymphangiomatosis involving structures and organs other than the spleen. This syndrome should be considered in obscure cases of splenomegaly in which the usual hematologic causes have been ruled out.

Laparoscopic cholecystectomy in acute cholecystitis.

Between August 1989 and December 1990, twenty-five patients with a preoperative diagnosis of acute cholecystitis underwent laparoscopic cholecystectomy. Twenty-one patients (84%) had abdominal tenderness, 16 (64%) had leukocytosis, and 10 (40%) had fever. Eleven patients (44%) came to the hospital with only one of these previously mentioned clinical signs. Six patients (24%) had two clinical signs. Eight patients (32%) came to the physician with all three findings. The length of surgery correlated directly with the number of presenting clinical signs. The average operating time was 119 minutes. Intraoperative cholangiograms were routinely performed on all patients. Four patients (16%) had common bile duct stones. The average hospitalization was 3.8 days and patients returned to work or routine physical activity between 3 days and 2 weeks (average 8 days) after surgery. There were three wound infections and two cases of hyperamylasemia. One patient developed urinary retention and another had a CO2 embolus. There were no intra-abdominal abscesses and no mortality. Laparoscopic cholecystectomy in acute cholecystitis is technically difficult. The incidence of common bile duct stones is greater than in elective cases, and routine cholangiography is crucial. With sufficient experience and skill, laparoscopic cholecystectomy can be performed safely in patients with acute cholecystitis.