Low dose aspirin: selective inhibition of rectal dialysis thromboxane B2 in healthy volunteers

Aim: To investigate the degree and selectivity of rectal thromboxane inhibition by low dose aspirin and there by investigate the contribution of platelet thromboxane to rectal thromboxane. Methods: The study was a randomized double-blind placebo controlled crossover study. Twelve healthy volunteers were studied, each over four separate study periods with two weeks wash-out between each period. Changes in levels of thromboxane (TX) B₂, prostaglandin (PG) E₂ and leukotriene (LT) B₂ in rectal dialysates were measured in response to 5 days oral low dose aspirin therapy in one of three once-daily formulations (plain 75 mg, plain 300 mg or enteric coated 300 mg), and compared to placebo. For each study period, rectal dialysates (4 h duration) were obtained at baseline and twice more after 5 days of aspirin or placebo therapy. Dialysate levels of thromboxane B₂, leukotriene B₄, prostaglandin E₂, and serum thromboxane B₂ were measured by radioimmunoassay. Results: Dialysate thromboxane B, levels were consistently inhibited by low dose aspirin (overall results of all formulations, 75 to 300 mg daily) from 1.06 ng/ml (geometric mean, 95 % CI:0.79–1.43 ng/ml) on placebo, by 29% (95% CI: 11–40%) to 0.75 ng/ml(0.56–1.01 ng/ml) (P= 0.046) on aspirin. In the absence of aspirin the level of prostaglandin E, was 1.47 ng/ml (0.97–2.23 ng/ml) and in the presence of aspirin was not significantly changed. The dialysate level of leultotriene B, was 0.45 ng/ml(0.34–0.61 ng/ml) in the absence of aspirin and there was no significant change on low dose aspirin. Serum thromboxane was inhibited by 80% to 20% of placebo values by plain aspirin 75 mg, by 95 % by plain aspirin 300 mg, and by 82 % by enteric coated aspirin 300 mg, respectively (P < 0.01). These results show that 29 % of the rectal thromboxane, but none of the rectal prostaglandin E₂ or leukotriene B₄, is inhibited by low dose aspirin. We infer that 34% of the rectal thromboxane B₂ is platelet-derived in our volunteers. Conclusion: Low dose aspirin will selectively inhibit a proportion of rectal thromboxane and may have prophylactic therapeutic potential in inflammatory bowel disease.     

Education in family and community health: the challenge faced by a new medical school

This paper describes the efforts of the Department of Family and Community Health at Sultan Qaboos University in providing opportunities for the development of 'hands-on' problem-solving skills appropriate for Oman. The curriculum of the Department is discussed, highlighting the unusual emphasis of this discipline in both the preclinical and clinical curriculum of the College of Medicine. The importance of continuous assessment and supervision of students is discussed. Course-work in the preclinical curriculum of the Department is kept to a minimum. Field-work forms an important part of preclinical training, where application and problem-based learning are emphasized. During the clinical years the students are exposed to an integrated series of lectures and practicals covering core knowledge in clinical medicine. Practical clinical training, over a total period of 15 weeks, takes place at a variety of sites where common problems in primary health care in Oman are handled by students under supervision.     

Coralline hydroxyapatite bone graft substitutes: preliminary report of radiographic evaluation

A new bone graft substitute made by conversion of the calcium carbonate exoskeleton of reef-building sea coral into hydroxyapatite has recently become clinically available. The normal radiographic appearance of two forms of this material is described. In the immediate postoperative period, the exoskeletal architecture of these implants is readily appreciated. With graft incorporation over the ensuing months, their intrinsic structure is gradually lost in association with poor marginal definition. Evolving radiographic findings reflect the biocompatible nature of these implants, which provides the potential for ingrowth of native bone with preservation of the coralline scaffold, resulting in enhanced biomechanical properties.     

Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

The superior laryngeal nerve loop and its surgical implications

Summary Based upon findings from 60 cadavers (120 sides), the incidence of superior laryngeal nerve loop, connecting the cervical sympathetic chain and the superior laryngeal nerve and its branches, the external and internal laryngeal nerve, was 98.3% (118 out of 120 sides). In most cases the loop connected the sympathetic chain and the external laryngeal nerve. The external laryngeal nerve was looped, and not linear as traditionally thought. The loop could be divided into three categories, V-shaped, U-shaped and mixed, and subdivided into 5 types and 17 subtypes according to morphological variation. The loop without exception innervated not only the cricothyroid muscle, but also the thyroid gland. The loop is one of the origins of the thyroid nerve. It seems that for thyroid surgery the loop, when lower in position, should be carefully separated from the superior thyroid vessels before the latter are ligated, in order to preserve a normal nerve supply to the muscle as well as to the part of the gland that remains after surgery.

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L'anse du nerf larynge supérieur, étude anatomique et applications chirurgicales

Résumé La fréquence d'une anse du nerf laryngé supérieur réalisant une anastomose entre la chaine sympathique cervicale et le nerf laryngé supérieur et/ou ses branches (rameau laryngé externe et ingerne), est de 98,3 % (118/120). Ce résultat s'appuie sur l'étude de 60 cadavres. Dans la plupart des cas, l'anastomose se fait entre la chaine sympathique cervicale et le rameau laryngé externe. Ce rameau laryngé externe a un trajet curviligne et non linéaire conformément aux données classiques. Il existe trois catégories d'anses : en "V", en "U" et mixte ; on peut également les subdiviser en 5 types et 17 sous-types en fonction des variations morphologiques. Cette anse innerve constamment non seulement le muscle cricothyroïdien mais aussi la glande thyroïde dont elle fournit une partie de l'innervation. Lors de la chirurgie thyroïdienne, si l'anse est en position basse, les nerfs doivent être soigneusement disséqués et séparés des vaisseaux thyroïdiens supérieurs avant ligature de ces derniers de façon à conserver l'innervation normale du muscle et de la partie restante de la glande.

     

消痔灵和强的松龙混合液治疗鼻息肉

0　引言　我科 1996 / 1998分别应用消痔灵与强的松龙混合液、消痔灵液、强的松龙液行鼻息肉内 ,鼻息肉蒂部注射治疗鼻息肉各 5 0例 ,并设对照组为鼻腔滴入及口服类固醇激素 5 0例 ,合计 2 0 0例 ,观察并对比其疗效 .1　对象和方法1.1　对象　男 12 8例 ,女 72例 ,年龄 8～ 78(平均 38)岁 ,病程 32 a～ 45 (平均 4.5 ) a.其中在本次治疗前做过一次鼻息肉摘除术后复发的 2 7例 ,做过 2次或 2次以上手术的 12例 .主要症状为鼻塞、流脓涕、头痛及嗅觉减退 .全部病例治疗前均行鼻窦 X线拍片 ,其中上颌窦炎 12 5例、筛窦炎 5 8例、蝶窦炎 2例、…