HPLC法测定血浆中六亚甲基二乙酰胺浓度

ＨＰＬＣ法测定血浆中六亚甲基二乙酰胺浓度赵玉喜，何晓英，蒋淼，谢景文，谢廷泉，任礼勤（兰州军区总医院药材科，兰州７３００５０）六亚甲基二乙酰胺（ｈｅｘａｍｅｔｈｙｌｅｎｅｂｉｓａｃｅｔａｍｉｄｅ，ＨＭＢＡ）是结构上与二甲基亚砜（ＤＭｓＯ）和Ｎ－甲基甲...     

The long-term effect of a protein-deficient-diet enriched with vitamin B6 on the blood parameters in unexercised and exercised rats

Protein undernutrition affects inter alia blood parameters and immune system. These negative effects may be improved by the addition of vitamin B6 to the diet. Here, we evaluated the effect of vitamin B6 supplementation and physical exercise in rats fed a protein-deficient diet. Rats were divided into six groups: exercised or unexercised – control, protein deficient, protein deficient with vitamin B6 supplementation. Sixty days of protein malnutrition caused significant changes in the rat body weight, haematological parameters (mainly red blood cells parameters), immunological parameters (NK and NKT cells) and biochemical parameters (total protein and albumin concentration and activity of AST). The rat exercise did not intensify the negative effects of protein malnutrition. The vitamin B6 supplementation in protein-deficient groups significantly improved body weight and red blood cell parameters. These results indicate that vitamin B6 should be considered as a valuable supplement for individuals suffering from protein malnutrition.     

Systematic Review of Vocational Preferences on Behavioral Outcomes of Individuals with Disabilities

Assessing performance of individuals with disabilities in relation to their preferences is a method of determining the social validity of practices. The benefits of using vocational preferences on related behavioral outcomes of individuals with disabilities such as task completion, challenging behavior, and indices of happiness, have been explored through several studies. The purpose of this systematic review was to assess the effects of preference for certain vocational activities on performance outcomes for individuals with disabilities. A comprehensive search resulted in a total of 16 included studies. Studies were analyzed according to (a) participant characteristics (e.g., diagnosis, age), (b) setting, (c) work tasks, (d) service provider, (e) experimental design or observational method, (f) preference assessment method, (g) independent variable, and (h) outcomes. Studies were appraised with quality indicators for single-case research. While outcomes were primarily positive in support of incorporating preferred vocational conditions, quality indicators were generally lacking and there are numerous areas calling for future research.     

An empirical evaluation of the performance of antibody identification tasks

Four empirical studies were conducted for better understanding of the nature of problem-solving activities by medical technologists and medical technology students when performing antibody identification tasks. The results indicated the importance of strategies that ensure the collection of converging evidence, as these strategies protect against the fallibility of commonly used heuristics and against errors due to simple slips. The results also indicate that not only do students make significant numbers of errors, but so do practicing technologists. In one of the studies covering a 1-year period, for instance, a group of 16 technologists made a total of 41 errors in 1057 cases. On the basis of these findings, several alternatives are proposed to reduce errors.     

Vitamin C improves endothelium-dependent vasodilation in patients with non-insulin-dependent diabetes mellitus.

Endothelium-dependent vasodilation is impaired in humans with diabetes mellitus. Inactivation of endothelium-derived nitric oxide by oxygen-derived free radicals contributes to abnormal vascular reactivity in experimental models of diabetes. To determine whether this observation is relevant to humans, we tested the hypothesis that the antioxidant, vitamin C, could improve endothelium-dependent vasodilation in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus. We studied 10 diabetic subjects and 10 age-matched, nondiabetic control subjects. Forearm blood flow was determined by venous occlusion plethysmography. Endothelium-dependent vasodilation was assessed by intraarterial infusion of methacholine (0.3-10 micrograms/min). Endothelium-independent vasodilation was measured by intraarterial infusion of nitroprusside (0.3-10 micrograms/min) and verapamil (10-300 micrograms/min). Forearm blood flow dose-response curves were determined for each drug before and during concomitant intraarterial administration of vitamin C (24 mg/min). In diabetic subjects, endothelium-dependent vasodilation to methacholine was augmented by simultaneous infusion of vitamin C (P = 0.002); in contrast, endothelium-independent vasodilation to nitroprusside and to verapamil were not affected by concomitant infusion of vitamin C (P = 0.9 and P = 0.4, respectively). In nondiabetic subjects, vitamin C administration did not alter endothelium-dependent vasodilation (P = 0.8). We conclude that endothelial dysfunction in forearm resistance vessels of patients with non-insulin-dependent diabetes mellitus can be improved by administration of the antioxidant, vitamin C. These findings support the hypothesis that nitric oxide inactivation by oxygen-derived free radicals contributes to abnormal vascular reactivity in diabetes.     

Defective T suppressor-inducer cell function in human immune deficiency virus-seropositive hemophilia patients

In human immune deficiency virus (HIV)-seropositive hemophilia patients, a low number of CD4 + lymphocytes is found, as well as a low CD4+/CD8+ ratio. In previous studies, it has been shown that antigen- specific T-helper cell (CD4+) function was present and no excessive antigen-specific T-suppressor cell (CD8+) function could be demonstrated. In this report, we studied another activity of CD4+ cells, namely the capacity to induce T-suppressor cell activity. The results clearly show a selective dysfunction of CD4+ suppressor-inducer (Tsi) cell function. Since these HIV-seropositive hemophilia patients showed the presence of activated B cells in the peripheral circulation refractory to antigen-specific T-helper cell signals and secreting specific antibodies spontaneously, we raised the hypothesis that the activated B cells in the patients activate the Tsi cells in vivo. This constant activation leads to a functional exhaustion of the Tsi cell pool.     

Self-generated diversity produces "insurance effects" in biofilm communities

Diversity generally protects communities from unstable environmental conditions. This principle, known as the "insurance hypothesis," has been tested in many different ecosystems. Here we show that the opportunistic pathogen Pseudomonas aeruginosa undergoes extensive genetic diversification during short-term growth in biofilm communities. The induced genetic changes are produced by a recA-dependent mechanism and affect multiple traits, including the behavior of the bacteria in biofilms. Some biofilm-derived variants exhibit an increased ability to disseminate, whereas others manifest accelerated biofilm formation. Furthermore, the presence of these functionally diverse bacteria increases the ability of biofilms to resist an environmental stress. These findings suggest that self-generated diversity in biofilms provides a form of biological insurance that can safeguard the community in the face of adverse conditions.     

Withdrawing versus not offering cardiopulmonary resuscitation: Is there a difference?

Conflict between substitute decision makers (SDMs) and health care providers in the intensive care unit is commonly related to goals of treatment at the end of life. Based on recent court decisions, even medical consensus that ongoing treatment is not clinically indicated cannot justify withdrawal of mechanical ventilation without consent from the SDM. Cardiopulmonary resuscitation (CPR), similar to mechanical ventilation, is a life-sustaining therapy that can result in disagreement between SDMs and clinicians. In contrast to mechanical ventilation, in cases for which CPR is judged by the medical team to not be clinically indicated, there is no explicit or case law in Canada that dictates that withholding/not offering of CPR requires the consent of SDMs. In such cases, physicians can ethically and legally not offer CPR, even against SDM or patient wishes. To ensure that nonclinically indicated CPR is not inappropriately performed, hospitals should consider developing ‘scope of treatment’ forms that make it clear that even if CPR is desired, the individual components of resuscitation to be offered, if any, will be dictated by the medical team’s clinical assessment.     

Treatment of progressive Hodgkin's disease with intensive chemoradiotherapy and autologous bone marrow transplantation

Twenty-six patients with progressive Hodgkin's disease after conventional chemotherapy received intensive chemoradiotherapy and autologous bone marrow transplantation (ABMT); 19 also received additional involved-field radiotherapy. Twenty-one patients [81%, 95% confidence intervals (CI) 61% to 94%] attained complete (n = 18) or partial responses. Ten patients (38%, 95% CI 20% to 59%) are disease- free a median of 4.5 years later (range 3.5 to 7.0 years), including seven patients with continuous complete responses. The likelihood of overall response was not significantly influenced by any clinical or treatment variable examined. However, there was a trend favoring patients with higher Karnofsky scores, and higher scores were associated with attainment of complete responses (P = .06 and P = .02, respectively, Mann-Whitney U test). Both higher Karnofsky scores and shorter durations of disease before transplantation were associated with improved survival in a stepwise Cox multivariate analysis. The chief cause of failure was progression at sites previously involved with Hodgkin's disease. No patient relapsed in the marrow, and two of three patients with a history of marrow involvement with Hodgkin's disease achieved durable complete responses after transplantation. These data suggest that inadequate pretransplant conditioning, and not the reinoculation of occult tumor cells in the autologous marrow, caused most relapses. Fatal treatment-related toxicity occurred in six patients. Three patients died of idiopathic interstitial pneumonitis; each had previously received local mediastinal irradiation before intensive chemoradiotherapy. Intensive chemoradiotherapy and ABMT produces durable responses in some patients with Hodgkin's disease incurable with conventional therapy. Use of such therapies at the first sign of failure with conventional chemotherapy and development of more effective conditioning regimens should further improve results.