An experiment in medical education. A critical analysis using traditional criteria

In 1984, in addition to its standard traditional curriculum, Rush Medical College (Chicago, Ill) developed a Socratic problem-based method of teaching basic science material called the alternative curriculum. As part of an evaluation of this new curriculum, students in the two curricula were compared using three traditional measurements: (1) test scores from the National Board of Medical Examiners, Part I; (2) test scores from the National Board of Medical Examiners, Part II; and (3) performance on an oral examination. Alternative curriculum students did not differ significantly from their traditional curriculum classmates on National Board of Medical Examiners, Part I and Part II total scores, although their subset scores on Part I did tend to be lower, reaching significance in one subset area. Differences in performance favoring the traditional curriculum were primarily seen in the early years of the program. Alternative curriculum students in the class matriculated in 1987 scored significantly higher in three of five categories on the oral examination.     

Ultrasensitive analysis of the intestinal absorption and compartmentalization of aluminium in uraemic rats: a 26Al tracer study employing accelerator mass spectrometry

BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit the determination of femtogram amounts of 26Al in blood and in various tissues with good precision and free of external contamination. METHODS: In the present study we used trace quantities of 26Al to investigate the intestinal absorption and compartmentalization of aluminium in rats with renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single oral doses of 20 ng 26Al were administered to six animals in each group and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone, liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al were significantly lower in uraemic rats compared to controls, whereas urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/- 6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in uraemia. The target tissues of cellular transferrin-mediated 26Al uptake, liver and spleen, tended to show a larger degree of aluminium accumulation in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27 pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site of extracellular aluminium deposition, 26Al concentrations were more elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g). Estimated total 26Al accumulation in all measured target tissues was significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/- 7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/- 6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our data suggest that fractional absorption from a dietary level dose of 26Al is about 0.13%. Compartmentalization occurs in transferrin-dependent target tissues such as liver and spleen; however, in quantitative terms extracellular deposition in bone is more important. Uraemia has a significant effect on the intestinal absorption and compartmentalization of aluminium. It enhances fractional absorption and increases subsequent extracellular deposition of aluminium in bone. However, at the same time uraemia does not increase transferrin-dependent cellular accumulation of aluminium in liver and spleen.      

Prevention of bacterial infection and sepsis in acute severe pancreatitis.

Between 1984 and 1986 six patients with acute respiratory failure (requiring ventilation for at least 3 days) complicating acute pancreatitis were managed on the intensive care unit (median ventilation period 6 days; range 3-41 days). Between 1987 and 1989 nine similar patients were managed (median ventilation period 35 days, range 4-69 days), and a regimen of enteral tobramycin, polymyxin and amphotericin to selectively decontaminate the digestive tract (SDD) was introduced. Five of six patients treated before 1987 had serious infections (three Gram-negative, one fungal), compared with only one of nine patients treated with SDD (P < 0.05). Clinical signs of sepsis were evident for 62% of the pre-SDD period, compared with 39% of the period during SDD therapy (P < 0.001). Systemic antibiotic prescribing was reduced in the SDD group; however, mortality remained unaffected with only two patients surviving pre-SDD and three during SDD treatment. SDD reduces infection rates and sepsis in patients with acute pancreatitis and may help to improve the prognosis of this life-threatening condition.     

骨形态计量学评价低钙对大鼠皮质骨的作用研究

目的 评价低钙饮食对大鼠皮质骨的影响。方法 3月龄SD普通级雄性大鼠40只，随机分为5组。第1、2组饲养1个月，分为正常对照组(1mol，ca1．0％)和极低钙组VLCD(1mol，Ca0．1％)，余下3组饲养3个月，分为正常对照组(3mol，Ca1．0％)、极低钙组VLCD(3mol，Ca0．1％)和低钙组LCD(3mol，Ca0．3％)。各组动物喂养包含对应钙含量的精制饲料，处死前进行双荧光标记。实验结束时，取左侧胫骨中段行骨形态计量学检测。结果 无论是低钙饮食1个月，还是3个月，无论是极度缺钙，还是仅有轻微的钙不足，胫骨中段横截面皮质骨始终未出现显著意义的变化，但骨内膜骨吸收有增加的趋势。结论 低钙对皮质骨作用不明显，这可能与机体在低钙状态下动用骨骼的次序或快慢有关。     

Red cell antigens and renal transplantation

Donor-specific transfusion was performed with and without cyclosporine between haplomismatched relatives prior to living-donor renal transplantation. Red cell antigen mismatching was not taken as a contraindication to DST. Of 80 patients included in the trial; eleven were ABO-mismatched, 15 were Rh(D)-mismatched, and a further 11 were transfused in the presence of atypical red cell antibodies (anti-D, -C, -Fya, -Kell -N, -H/I -I, -P1, -Wra). Patients were randomized to receive cyclosporine (10 mg/kg) daily during DST or not (control group). The presence of atypical red cell antibodies, with the exception of Rh anti-D, did not appear to influence DST or renal transplantation. DST did not act as a primary stimulus to Rh anti-D production but stimulated preexisting anti D levels. ABO mismatching did not appear to influence DST or subsequent renal transplantation except in one group A [corrected] patient who received group O [corrected] blood and cyclosporine. This patient developed a severe, but self-limiting, autoimmune hemolytic anemia due to auto-anti A antibodies. A similar group A patient in the control group developed an auto-antibody with no clinical sequelae. The influence of cyclosporine on the development of this auto-antibody is uncertain. We conclude that, with the exception of preexisting anti-D antibodies, minor red cell antigen disparities should not preclude pretransplant conditioning with donor-specific transfusions.     

Gram-negative sepsis: a dilemma of modern medicine.

Gram-negative sepsis is an increasingly common problem, with up to 300,000 cases occurring each year in the United States alone. Despite the ongoing development of new antibiotics, mortality from gram-negative sepsis remains unacceptably high. To stimulate earlier therapeutic intervention by physicians, a new set of broad definitions has been proposed to define the systemic inflammatory response characteristic of sepsis. In this review, the signs and symptoms of this progressive, injurious process are reviewed and its management is discussed, as are the mechanisms by which bacterial endotoxin triggers the biochemical events that lead to such serious complications as shock, adult respiratory distress syndrome, and disseminated intravascular coagulation. These events often occur even when appropriate antimicrobial therapy has been instituted. An increased understanding of the structure of endotoxin and its role in the development of sepsis, together with advances in hybridoma technology, has led to the development of monoclonal antibodies that bind to endotoxin and significantly attenuate its adverse effects. These agents promise to substantially reduce the morbidity and mortality associated with gram-negative sepsis.     

Effect of acquisition and analysis routines on gated blood pool measurements

Results obtained from gated equilibrium blood pool (GBP) studies are not only dependent on intrinsic variations, but also on the way in which images are acquired and analysed. The aim of this study was to investigate factors which could affect left ventricular time-activity curves. Temporal resolution was studied by comparing studies of 20 and 40 frames beat-1. Forty frames per beat resulted in a mean left ventricular ejection fraction of 0.48 compared to 0.46 for 20 frames beat-1. The mean difference of 0.02 was significant (P less than 0.01) as was the mean difference in maximum emptying rate (MER = 0.28, P less than 0.01) and in maximum filling rate (MFR = 0.38, P less than 0.01). No significant differences in ejection fraction (EF) values were found between acquisitions made in list and frame mode, but the mean differences for MER = 0.03 (P less than 0.05) and MFR = 0.01 (P less than 0.02) were significant. For patient repositioning and intra-observer variations no significant differences were found. In patients with normal EF values (greater than 0.5) no significant differences were found in the inter-observer study. In patients with anterior myocardial infarction (AMI), significant differences were found in EF, MER and MFR (EF = 0.02, P less than 0.001; MER = 0.2, P less than 0.01; MFR = 0.24, P less than 0.01). Significant differences were found in all values when comparing a semi-automatic method of evaluation with two automatic methods. In conclusion the results from this study suggest that acceptable reproducibility can be achieved in GBP studies, provided the method of analysis is not changed between studies.     

Lack of Autoimmune Serological Reactions in Rodent Models of Insulin Dependent Diabetes Mellitus

Spontaneous insulitis with insulin-dependent diabetes mellitus (IDDM) in rodent models, the BB rat and NOD mouse, has clarified the pathogenesis of and guided decisions on interventional therapy for human IDDM. However, the occurrence in such models of a standard marker of human IDDM, autoantibodies to β islet cell constituents, has been controversial. Hence we assessed diabetes-prone rodents for the frequencies of raised levels of auto-antibodies to glutamic acid decarboxylase GAD (anti-GAD), insulin and heat shock protein 65 (HSP-65) in relation to levels in non-diabetes-prone animals and levels in human diabetic sera. Assays were performed sequentially at various ages of life. The immunoassays used for anti-GAD and anti-insulin were those validated for sensitivity and specificity for detection of the corresponding autoantibodies in human IDDM sera at international workshops. Positive controls included human IDDM sera with reactivity with GAD or insulin and, for mouse anti-GAD, the highly reactive monoclonal antibody, GAD-6. The results were that levels of autoantibodies in diabetes-prone BB rats or NOD mice to the ‘IDDM-relevant’ autoantigens in our panel did not exceed levels in control rats or mice, and were much lower than levels in humans with IDDM. We conclude that the BB rat and NOD mouse represent a model, but not a facsimile, of human IDDM and that therapeutic successes in such models should be interpreted with caution in relation to interventional therapy for human IDDM.