Managing trainee doctors in difficulty.

When the conduct, performance or health of a doctor in training is called into question, there is often confusion about the roles and responsibilities of the parties involved. Where does training stop and employment begin? When should poor performance trigger intensified training, and when should it lead to dismissal? How much information should be transferred from employer to employer as a trainee moves around a training programme? This article describes one Deanery's approach.     

Cannabinoids, loratadine and allopurinol as novel additions to the antipsoriatic ammunition

As the current antipsoriatic medications are commonly associated with deleterious side-effects, a determined search for safer agents, which could be used alone or in combination with current antipsoriatic drugs, would be very imperative. Psoriasis is believed to be characterized by a type 1 cytokine pattern; interferon-gamma, interleukin (IL)-2 and tumour necrosis factor (TNF)-alpha are predominantly expressed in this disorder. Nitric oxide, reactive oxygen species, histamine, leukotriene B4, and decreased [corrected] keratinocyte cyclic adenosine monophosphate/cyclic guanosine monophosphate (cAMP/cGMP) ratio are supposed to play roles in the pathogenesis of this disorder. Based on the immunopathogenesis of psoriasis, this paper introduces three novel, potential treatments for this clinical conundrum: (i) cannabinoids, which exert inhibitory effects on antigen processing and macrophage/T-cell interaction and also on the release of IL-2, TNF-alpha and nitric oxide from immune cells; (ii) loratadine, which is an antihistamine capable of increasing [corrected] the cAMP/cGMP ratio and the production of leukotriene B4; and (iii) allopurinol, which scavenges free radicals, inhibits the production of TNF-alpha, and downregulates the expression of intercellular adhesion molecule-1 and P2X7 receptors on monocytes/macrophages, which are involved in antigen presentation and production of the inflammatory response, respectively. Importantly, allopurinol, especially in combination with cyclosporin, has been shown to be effective against experimental autoimmune uveitis, which, like psoriasis, is a cell-mediated autoimmune disorder.     

Evidence that Wra and Wrb are antithetical

Studies on 24 Wr(a+b+) and 23 Wr(a-b+) blood samples, using anti-Wrb in the enzyme-linked antiglobulin test (ELAT), have shown that Wr(a+b+) red cells bind, on average, a little over half the amount of anti-Wrb bound by Wr(a-b+) red cells. Similarly, ELAT studies using six different anti-Wra and 10 Wr(a+b+) samples, as well as red cells from the original Wr(a+b-) proposita, have shown that Wr(a+b+) red cells bind about half the amount of anti-Wra bound by Wr(a+b-) red cells. Various pitfalls that can arise when the ELAT is used to measure antigen ratios on red cells have been avoided but are described. This conclusive evidence that Wra and Wrb have an antithetical relationship is discussed in light of the knowledge that a ficin-resistant portion of MN sialoglycoprotein (SGP), when carried in liposomes, can inhibit anti-Wrb. It is possible that Wra, Wrb, or both may encode a post-translational change in MN SGP, or production of transferases that glycosylate membrane lipids that affect in situ orientation of MN SGP, or production of protein band 3 that then forms a complex with MN SGP at the red cell membrane surface.     

大鼠脂肪间充质干细胞的成骨分化

目的:观察大鼠脂肪间充质干细胞经成骨诱导向成骨细胞分化的生物学特性,探讨其作为骨组织工程种子细胞的可行性。方法:实验于2004-07/2006-03在中南大学湘雅医院中心实验室完成主要工作。①取健康SD大鼠双侧腹股沟区脂肪垫,消化法分离出脂肪间充质干细胞,接种入含有体积分数为0.1的新生牛血清的低糖DMEM培养基进行原代培养。②取第3代的脂肪间充质干细胞,用含有体积分数为0.1的新生牛血清、0.1μmol/L地塞米松、50μmol/L抗坏血酸、10mmol/Lβ-甘油磷酸钠的高糖DMEM培养基诱导其向成骨细胞分化。③于3,5,7,10,12,14,21d分别采用倒置显微镜观察细胞形态及增殖情况、Gomori改良钙钴法碱性磷酸酶染色、茜素红S钙结节染色和Ⅰ型胶原免疫细胞化学染色检测脂肪间充质干细胞成骨分化的情况。结果:①脂肪间充质干细胞原代细胞呈成纤维细胞样长梭形外观,传代稳定,细胞形态均一。②经成骨诱导,脂肪间充质干细胞体积增大,呈多角形;成骨诱导14d,Gomori改良钙钴法碱性磷酸酶染色,细胞胞浆内可见浅棕色至棕黑色的颗粒,平均染色阳性率为80%;碱性磷酸酶活性随时间的延长而逐渐增高[3,5,7,10,12,14d依次为(2.43±0.09),(3.60±0.08),(5.01±0.09),(7.75±0.07),(9.59±0.09),(10.94±0.10)μkat/L];成骨诱导21d,钙结节形成明显,茜素红S染色,呈红色结节;成骨诱导7d,Ⅰ型胶原免疫细胞化学染色,细胞胞浆呈棕黄色,胞核经苏木精复染为蓝色。结论:大鼠脂肪间充质干细胞经成骨诱导具有成骨细胞的生物学特性,可作为骨组织工程的种子细胞。     

Neuromuscular function of the latissimus dorsi muscle in goats after dynamic cardiomyoplasty

Skeletal muscle deterioration is emerging as a limitation to long-term cardiac assist by dynamic cardiomyoplasty. Chronic electrical stimulation of in situ skeletal muscle showed that ischemia, decreased muscle preload, muscle overuse, and chronic electrical stimulation are factors for muscle deterioration. Transposition around the heart has been associated with signs of muscle denervation after chronic electrical stimulation. To evaluate latissimus dorsi muscle neuromuscular function after longterm dynamic cardiomyoplasty, we performed neuromuscular functional analysis and histology on the latissimus dorsi muscle and thoracodorsal nerve of six normal goats and six goats after 6 months of dynamic cardiomyoplasty. Electromyographic analysis showed positive sharp waves and fibrillation potentials in the latissimus dorsi of three goats from the dynamic cardiomyoplasty group. Conduction velocity of the thoracodorsal nerve of goats from the dynamic cardiomyoplasty group (58.32+/-9.80 m/s) was reduced compared to the goats from the control group (71.48+/-5.71 m/s, P = 0.02). Histologic changes in skeletal muscle were compatible with denervation. Loss of myelin sheaths, collapse of endoneurial connective tissue, and solitary foci of axonophagia and myelinophagia further documented severe injury to the thoracodorsal nerve in goats from the dynamic cardiomyoplasty group. The latissimus dorsi muscle wrap was denervated after long-term dynamic cardiomyoplasty. Traction on the neurovascular pedicle at each contraction of the transposed muscle may induce afferent axonal injury of the thoracodorsal nerve resulting in diminished muscular function.     

Comparing vibrissal morphology and infraorbital foramen area in pinnipeds

Pinniped vibrissae are well-adapted to sensing in an aquatic environment, by being morphologically diverse and more sensitive than those of terrestrial species. However, it is both challenging and time-consuming to measure vibrissal sensitivity in many species. In terrestrial species, the infraorbital foramen (IOF) area is associated with vibrissal sensitivity and increases with vibrissal number. While pinnipeds are thought to have large IOF areas, this has not yet been systematically measured before. We investigated vibrissal morphology, IOF area, and skull size in 16 species of pinniped and 12 terrestrial Carnivora species. Pinnipeds had significantly larger skulls and IOF areas, longer vibrissae, and fewer vibrissae than the other Carnivora species. IOF area and vibrissal number were correlated in Pinnipeds, just as they are in terrestrial mammals. However, despite pinnipeds having significantly fewer vibrissae than other Carnivora species, their IOF area was not smaller, which might be due to pinnipeds having vibrissae that are innervated more. We propose that investigating normalized IOF area per vibrissa will offer an alternative way to approximate gross individual vibrissal sensitivity in pinnipeds and other mammalian species. Our data show that many species of pinniped, and some species of felids, are likely to have strongly innervated individual vibrissae, since they have high values of normalized IOF area per vibrissa. We suggest that species that hunt moving prey items in the dark will have more sensitive and specialized vibrissae, especially as they have to integrate between individual vibrissal signals to calculate the direction of moving prey during hunting.     

Trichinella infection and clinical disease

Trichinellosis is caused by ingestion of insufficiently cooked meat contaminated with infective larvae of <it>Trichinella</it> species. The clinical course is highly variable, ranging from no apparent infection to severe and even fatal disease. We report two illustrative cases of trichinellosis. Returning to Denmark a few days after having eaten roasted pork in the Republic of Serbia, a female patient suffered from severe vomiting, epigastric pain, diarrhoea, and later myalgia, generalized oedema, and prostration. A biopsy showed heavy infestation with <it>Trichinella spiralis</it>, 2000 larvae/g of muscle. Life-threatening cardiopulmonary, renal and central nervous system complications developed. The patient recovered after several months. Her husband, who also ate the pork, did not have clinical symptoms, but an increased eosinophil count and a single larva in a muscle biopsy confirmed infection. The epidemiology, clinical manifestations, diagnosis, treatment and prevention of trichinellosis are reviewed.