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51.
Patrick M. Rao M.D. James T. Rhea M.D. Robert A. Novelline M.D. 《Emergency radiology》1997,4(5):268-275
This article reviews a focused helical appendiceal computed tomographic technique and discusses an approach to appendiceal computed tomographic interpretation. 相似文献
52.
Trenimon belongs to a class of aziridinylbenzoquinone anticancer drugs that cross the blood-brain barrier. In this study we have investigated the molecular mechanisms for trenimon-induced toxicity in aerobic versus hypoxic conditions with the use of freshly isolated rat hepatocytes. The following evidence suggests the mechanisms for trenimon detoxification involves reduction by DT-diaphorase, while the cytotoxic mechanism involves macromolecular alkylation under hypoxic conditions as well as oxidative stress under aerobic conditions. (a) Hepatocyte cytotoxicity induced by trenimon (250 microM) under aerobic conditions ensued following an initial induction of cyanide-resistant respiration and partial oxidation of glutathione to oxidized glutathione. Trenimon reduction to the hydroquinone by the hepatocytes was rapid. Inhibition of hepatocyte DT-diaphorase by dicumarol increased trenimon-induced cytotoxicity by approximately 10-fold, and markedly inhibited hydroquinone formation. Furthermore, both cyanide-resistant respiration and oxidized glutathione formation were markedly increased, resulting in depletion of oxygen in the media. Trenimon reduction to the hydroquinone then occurred. This suggests that DT-diaphorase in normal hepatocytes prevents the formation of the semiquinone that causes cytotoxic protein alkylation and oxidative stress. (b) Hepatocyte cytotoxicity induced by trenimon (350 microM) under hypoxic conditions ensued following glutathione depletion without oxidized glutathione formation. Inactivation of hepatocyte DT-diaphorase by dicumarol under hypoxic conditions increased trenimon-induced cytotoxicity by approximately 3.5-fold and increased semiquinone radical levels 2-fold without affecting its reduction rate. This suggests that the cytotoxic mechanism involves protein alkylation by semiquinone radicals formed by reductases catalyzing a one-electron reduction of trenimon. 相似文献
53.
54.
Which patient, which pump? 总被引:1,自引:0,他引:1
55.
This study reviews five cases of women with hyperthyroidism, three black women and two Hispanic women. Initially, two patients presented with voice changes, weight loss, and increased appetite. Only two patients presented with classical symptoms of hyperthyroidism. Examination showed all patients had diffusely enlarged thyroids and exaggerated reflexes. Two patients showed Graves'' opthalmopathy. 相似文献
56.
57.
A direct solution is proposed to an optimal control problem of linear econometric systems with a quadratic welfare loss function when there are linear equality constraints on the control variables. The direct solution proposed here eliminates the problem of non-uniqueness of the optimal solution, which is present when this optimal control problem is solved using the recursive algorithm proposed by Chow,1 Pindyck2 and Tan.3 If a unique solution to the optimal control problem exists, then the direct solution and the recursive solution coincide. 相似文献
58.
On the Acylation of Hydroxy- and Mercaptocarboxylic Acid Esters Using the Carbodiimide/Acylation Catalyst Method Acylation of esters of hydroxycarboxylic acids can be carried out easily and in good yields by using the carbodiimide/acylation catalyst method. The reaction has also been applied to dihydroxy- and mercaptocarboxylic acid esters. The compounds formed from certain esters of hydroxycarboxylic acids are unstable to heat and decompose easily to the free carboxylic acid. No racemization is observed when using enantiomeric hydroxycarboxylic acids. Use of racemic carboxylic acids leads to diastereomers, whose 1H-NMR shifts for characteristic protons are different as expected. Five drugs are among the carboxylic acids investigated in this context. 相似文献
59.
Cytotoxic effects of various quinone compounds are thought to be due to the formation of semiquinone free radicals. Hydroquinone and 1,2,4-benzenetriol in the presence of copper ions release from glutamate or DNA aldehydic products capable of reacting with 2-thiobarbituric acid (TBA). The formation of TBA reactive products (TBAR) was greater in the presence of 1,2,4-benzenetriol in comparison with hydroquinone. Complete inhibition of formation of TBAR from glutamate by 1,2,4-benzenetriol and copper was observed in the presence of catalase, thiourea and mannitol. Albumin and superoxide dismutase offered substantial protection. Complete protection of formation of TBAR from DNA was observed in the presence of catalase and thiourea. Presence of albumin, mannitol and superoxide dismutase caused only partial inhibition. The formation of TBAR from glutamate or DNA is dependent on copper ion concentration. The present data indicate that hydroquinone and 1,2,4-benzenetriol in the presence of copper ions can lead to the formation of reactive hydroxyl radicals which can release TBAR from glutamate or DNA. 相似文献
60.
Total joint arthroplasty is among the most remarkable advances in orthopaedic surgery for the elderly, enabling themto regain physical function and be free of pain. Although uncommon, infection of the prosthetic joint causes serious morbidity leading to poor functional outcome with a mortality approaching 8% in the elderly. Most infections occur through inoculation of the prosthesis at the time of implantation and are due to Gram-positive cocci, although a third of the episodes are due to Gram-negative bacilli from a secondary focus. The management presents a major clinical and therapeutic challenge due to systemic and local comorbid conditions in the elderly. Medical and surgical treatment decisions for infected joint prosthesis are complex and should be individualized in each case. Optimal nutrition is essential for a successful outcome. Adverse reactions to medications are more common in the elderly due to end organ dysfunction and drug-drug interactions. 相似文献