The evolution of morphologic and biomechanical changes in reversed and in-situ vein grafts.

A comparative study of experimental reversed (RV) and in-situ (INS) vein grafts with respect to the evolution of morphologic and compliance characteristics was done in a canine model. In addition, the compliance characteristics in a series of human INS vein grafts were recorded as a function of time after operation. At 6 months after implantation, all experimental grafts displayed well-developed intimal hyperplasia. There was no significant difference in either absolute intimal thickness (INS 0.133 +/- 0.09 mm vs. RV 0.085 +/- 0.06 mm; NS) nor in the percentage of the total wall thickness occupied by the intima when experimental INS grafts were compared with RV grafts after 6 months. Similarly, compliance values of INS and RV vein grafts were similar at all time intervals examined up to 6 months after operation. Thirty-three human INS vein grafts had a mean compliance value of 1.74 +/- 0.72 (percent radial changes per mmHg X 10(-2) at a median postoperative interval of 14 weeks. This value did not differ significantly from those measured in the INS vein grafts. Although all vein grafts examined retained their native viscoelastic properties, this study suggests that functioning human INS vein grafts are less compliant than previously suspected on the basis of prior ex-vivo and clinical studies of RV saphenous vein grafts. The purported clinical superiority of the INS vein graft cannot be explained on the basis of superior biomechanical performance or failure to develop intimal hyperplasia.     

抗胆碱药3-(2-苯基-2-环戊基-2-羟基-乙氧基)奎宁环烷的立体化学和构效关系

研究了强效抗胆碱药dl-3-(2-苯基-2-环戊基-2-羟基-乙氧基)-奎宁环烷的四个光学异构体的两种不对称合成方法,用HPLC检测了异构体含量,讨论了构效关系。     

Acute Renal Allograft Rejection Following Pegylated IFN-α Treatment for Chronic HCV in a Repeat Allograft Recipient on Hemodialysis: A Case Report

Interferon alpha (IFN-alpha) can be effective therapy for patients with chronic kidney disease who have chronic hepatitis C (HCV). However, acute allograft rejection has been reported in association with IFN-alpha following kidney transplantation, and therefore IFN therapy is recommended prior to, rather than after, kidney transplantation whenever feasible. The special case of repeat allograft recipients who contract HCV after the first transplantation presents special difficulties. This report features the case of a repeat allograft recipient who presented with neutropenic fevers after 5 months of pegylated IFN-alpha therapy, initiated 6 months following the functional loss of his third graft and the reinitiation of hemodialysis (HD). Physical exam, radiographic and laboratory findings led to allograft nephrectomy. The pathologic findings supported a diagnosis of acute-on-chronic rejection. This represents a rare case of IFN-alpha induced rejection following allograft failure and return to HD in a repeat allograft recipient. It also calls attention to the need for a high index of suspicion for the development of allograft rejection, which may require allograft nephrectomy even after allograft 'failure'.     

Self-evaluation and its relationship to clinical evaluation

An exploratory study was undertaken in a three-year nursing diploma program to determine instructor and student perceptions of self-evaluation (SE) and its relationship to clinical evaluation. A cross-section of instructors (n = 9) participated in three rounds of a Delphi survey. From this validated data base a questionnaire was developed and distributed to a stratified sample of 145 students. Combined results were then analyzed and compared. Results indicated that both students and instructors perceive self-evaluation more positively than negatively and they see the main purpose as providing direction for learning. Contrary to the literature and perceptions of surveyed instructors, students did not perceive self-evaluation as a factor in promotion of professional growth. Although students value a participatory role in clinical evaluation, the process of self-evaluation generates anxiety and underrating of performance. The authors conclude that self-evaluation is a developmental skill requiring guidelines and practice, and offer recommendations for its use.     

The effect of dextrose and amino acids on respiratory function and energy expenditure in morbidly obese patients following gastric bypass surgery

Hypocaloric dextrose administration results in a diminished minute ventilation, metabolic rate, and ventilatory responsivity to hypercapnea and hypoxia which is rapidly reversed by provision of amino acids in individuals of normal weight. This study compared the effects of peripheral intravenous dextrose and amino acid infusion on respiratory parameters and energy expenditure in 25 morbidly obese patients undergoing gastric bypass surgery. On the first postoperative day, respiratory rate increased (P less than 0.01) and tidal volume decreased (P less than 0.001) maintaining minute ventilation at slightly less than preoperative levels but on subsequent days minute ventilation exceeded baseline values (P less than 0.005) primarily by a sustained increased respiratory rate. Oxygen consumption (P less than 0.005), carbon dioxide production (P less than 0.05), and resting energy expenditure (P less than 0.01) all declined 25% from baseline values on the first postoperative day and subsequently reverted to preoperative values. The type of intravenous fluid had no effect on any of these parameters. A significant difference in respiratory quotient (P less than 0.05) was noted between the two intravenous fluid regimens attributable to the oxidation of the dextrose calories. The failure to detect a difference in metabolic rate or to stimulate respiration despite elevation of serum branched chain amino acids (P less than 0.0001) and ketone bodies (P less than 0.0001) with protein infusion does not suggest a role for nutrient manipulation of respiration in the postoperative care of the morbidly obese patient.     

Risk of needlesticks and occupational exposures among residents and medical students.

PROBLEM--Occupational exposure to human immunodeficiency virus (HIV) disease is a problem of concern to all health care workers, especially those in large urban teaching hospitals with large numbers of HIV-positive patients. METHOD--The self-reported incidence of needlesticks and other exposures to patients' blood and body fluids in 550 medical students and residents at the Los Angeles County-University of Southern California Medical Center during the 1989 through 1990 training year was studied by means of an anonymous survey. RESULTS--Seventy-one percent of respondents reported one or more needlesticks or other exposures during the training year. Surgical residents had a sixfold greater rate of occupational exposure compared with medicine residents and were significantly more likely to experience suture needlesticks, cuts, open wound contamination, and mucous membrane exposure. Medical students generally were at somewhat lower risk compared with residents, but had greater rates of hollow-needle puncture accidents. No trend was found for accidental exposure by level of residency training. The known HIV-positive exposure rate for students and residents was 9.5% per person per year. Only 9% of exposures were actually reported to the health center. CONCLUSIONS--Based on the rate of exposures reported, numbers of known and estimated HIV-positive patients, and previously published HIV seroconversion rates, we would expect an annual rate of HIV seroconversion rates, we would expect an annual rate of HIV seroconversion as a result of occupational exposures of between 27 and 46 per 100,000. This rate is similar to the leading cause of death in this age group--motor vehicle accidents--and is equivalent to one student or resident in this medical center seroconverting every 2 to 3 years. Although only a portion of accidental exposures are regarded as preventable, these data emphasize the importance of increased efforts toward improved education, prevention, and accessibility of protective equipment.     

Examining Equivalence of Concepts and Measures in Diverse Samples

While there is growing awareness for the need to examine the etiology of problem behaviors across cultural, racial, socioeconomic, and gender groups, much research tends to assume that constructs are equivalent and that the measures developed within one group equally assess constructs across groups. The meaning of constructs, however, may differ across groups or, if similar in meaning, measures developed for a given construct in one particular group may not be assessing the same construct or may not be assessing the construct in the same manner in other groups. The aims of this paper were to demonstrate a process of testing several forms of equivalence including conceptual, functional, item, and scalar using different methods. Data were from the Cross-Cultural Families Project, a study examining factors that promote the healthy development and adjustment of children among immigrant Cambodian and Vietnamese families. The process described in this paper can be implemented in other prevention studies interested in diverse groups. Demonstrating equivalence of constructs and measures prior to group comparisons is necessary in order to lend support of our interpretation of issues such as ethnic group differences and similarities.