Abnormal surfactant composition and activity in severe bronchiolitis

A prospective study of infants under 1 y of age, ventilated for severe viral bronchiolitis, was carried out in four paediatric intensive care units in order to study surfactant activity and composition in this condition. Lung lavage fluid from 24 infants with bronchiolitis, 19 with bronchiolitis and sepsis or cardiac failure and 12 controls were analysed by the “click test” for surfactant activity and for phospholipids. Surfactant activity was present in all controls, but in only 2 of the 24 infants with bronchiolitis alone. The presence of phosphatidylglycerol correlated perfectly with the click test, suggesting that reduced activity is due to changes in surfactant lipid composition. In those with bronchiolitis plus coexisting disease, surfactant activity and phosphatidylglycerol were absent in only half. Surfactant activity and phosphatidylglycerol re-appeared by extubation. Severe viral bronchiolitis is associated with an absence of surfactant activity and PG, which resolves by clinical recovery. Infants with coexisting conditions are not always surfactant deficient. Surfactant administration is likely to be beneficial, but requires a selective approach.     

Meniscal injuries: detection using MR imaging

Both retrospective and blinded analyses of thin-section, high-resolution magnetic resonance (MR) images of the knee joint, produced using a solenoid surface coil, indicate that MR imaging is an effective technique for evaluating meniscal injuries. Images of 49 patients were evaluated, and the results were correlated with those of subsequent arthroscopy. A grading scale was developed to rate the index of suspicion of a meniscal tear based on the MR images. Overall, approximately 80% of menisci rated grade 4 (definite tear) or 3 (probable tear) were found to have corresponding tears at arthroscopy. In many other patients with a grade 4 or 3 meniscus in whom a corresponding tear was not found arthroscopically, meniscal tears at other sites or other abnormalities were correctly diagnosed using MR. A majority of the false-positive MR images involved the posterior horns of the menisci, the sites of most false-negative arthroscopic diagnoses. The predictive value of a negative MR image was almost 100%. Even in patients with moderate-to-large effusions, the menisci were accurately evaluated. The results imply that MR imaging is useful in the preoperative evaluation of suspected meniscal tears.     

Changing mortality and causes of death in infants 23–27 weeks'' gestational age

OBJECTIVE: To contrast the mortality rates and changes in the causes of death of very preterm infants (23-27 weeks), before and after the introduction of exogenous surfactant in 1991, and to identify any preventable causes of death remaining in the 1990s. METHODOLOGY: This was a cohort study on consecutive preterm infants of 23-27 weeks' gestational age born in the Royal Women's Hospital, Melbourne, a level III perinatal centre. The infants were livebirths free of lethal anomalies from two distinct eras, 1983-90, and 1992-96, inclusive. The main outcome measures were mortality during the primary hospitalization and the causes of death before and after the introduction of exogenous surfactant in 1991. RESULTS: In 1983-90, 261 of 508 livebirths (51.4%) of 23-27 weeks' gestational age died, a significantly higher proportion than the 109 of 384 (28.4%) livebirths who died in the period 1992-96. The mortality rate fell significantly with increasing gestational age and was lower at each week of gestational age in 1992-96. More infants who died in 1992-96 were treated intensively in the neonatal intensive care unit (NICU). Of the group of infants who died or who were treated intensively in NICU, respiratory causes of death predominated. However, the causes of death changed over time. In 1992-96 proportionally fewer infants died from respiratory causes (1983-90, 82.5%; 1992-96, 60.0%; odds ratio (OR) 0.31, 95%; confidence interval (CI) 0.16-0.57), but more from septic causes (1983-90, 14.3%; 1992-96, 43.8%; OR 4.9, 95%; CI 2.6-9.2). CONCLUSIONS: As the mortality rate has fallen over time, respiratory causes of death have diminished, but septic causes of death have increased. Further advances in the use of exogenous surfactant and respiratory support may reduce respiratory deaths. Effective strategies to reduce nosocomial infections are urgently required.     

Creutzfeldt--Jakob Disease in Recipients of Human Growth Hormone in the United Kingdom: A Clinical and Radiographic Study

In the past 3 years there have been five further cases, in additionto one case reported in 1985, of Creutzfeldt-Jakob disease inrecipients of human growth hormone in the United Kingdom. Theclinical findings of two of these cases are described, demonstratinga typical presentation with a predominantly cerebellar syndromeat onset which is not commonly a presenting feature of sporadicCreutzfeldt-Jakob disease. In one case a ^99mTc hexamethylpropylenaminesingle photon emission tomographic scan showed marked impairmentof tracer uptake in the basal ganglia and cerebral cortex ata time when the clinical picture was predominantly cerebellar.This technique may be useful in early diagnosis. In the othercase post mortem examination of the brain showed prominent amyloiddeposition in the cerebellum, which has not been described previouslyin pituitary-hormone related Creutzfeldt-Jakob disease. Thepreviously published cases of growth hormone-related Creutzfeldt-Jakobdisease are reviewed and reasons for the particular clinicalpattern seen are discussed.     

中药天年饮对衰老大鼠脾淋巴细胞增殖转化能力的影响

目的:观察中药天年饮对衰老大鼠抗氧化能力、脾淋巴细胞增殖转化能力及免疫器官指数的影响。方法:实验于2006-04/07在承德医学院基础医学研究所完成。选择清洁级4月龄雄性SD大鼠40只,按随机数字表法分为4组:正常对照组、衰老模型组、天年饮用药组和阴性对照组,每组10只。正常对照组大鼠常规饲养,自由摄食、饮水。衰老模型组、天年饮用药组和阴性对照组大鼠均采用D-半乳糖连续腹腔注射制备亚急性衰老的大鼠模型。衰老模型组大鼠造模成功后不再做任何处理;天年饮用药组大鼠造模成功后每天用天年饮(由炙何首乌、怀牛膝、肉从蓉、淫羊藿、丹参、茯苓等6味中药组成,经熬制后含生药1.5g/mL,购自承德医学院附属肛肠医院)灌胃(8.1g/kg),共30d;阴性对照组大鼠在造模成功后每天用同等剂量的生理盐水灌胃,时间同天年饮用药组大鼠。造模后30d采用噻唑蓝法检测脾淋巴细胞的增殖转化能力,同时分别检测大鼠血清超氧化物歧化酶活性、丙二醛含量以及大鼠的胸腺指数和脾脏指数。结果:纳入动物40只,均进入结果分析。①衰老模型组大鼠血清超氧化物歧化酶活性低于正常对照组、丙二醛含量高于正常对照组,差异有显著性意义[分别为(1.77±0.16),(2.48±0.22)mkat/L,t=2.613,P<0.05;(447.70±31.20),(267.54±40.82)nmol/L,t=11.088,P<0.01];天年饮用药组大鼠血清超氧化物歧化酶活性高于衰老模型组、丙二醛含量低于衰老模型组,差异有显著性意义[分别为(2.33±0.26),(1.77±0.16)mkat/L,t=-2.258,P<0.05;(276.32±23.30),(447.70±31.20)nmol/L,t=13.917,P<0.01]。②衰老模型组大鼠胸腺指数、脾脏指数和脾淋巴细胞的增殖转化能力(A)低于正常对照组,差异有显著性意义(分别为0.0775±0.0309,0.1239±0.0436,t=2.745,P<0.05;0.347±0.099,0.466±0.108,t=2.568,P<0.05;0.388±0.054,0.470±0.063,t=3.125,P<0.01);天年饮用药组大鼠胸腺指数、脾脏指数和脾淋巴细胞的增殖转化能力(A)高于衰老模型组,差异有显著性意义(分别为0.1130±0.0456,0.0775±0.0309,t=2.238,P<0.05;0.451±0.111,0.347±0.099,t=2.211,P<0.05;0.447±0.061,0.388±0.054,t=2.2902,P<0.05)。结论:中药天年饮可提高机体的抗氧化能力及免疫功能,具有延缓衰老的作用。     

Expression and function of receptors for stem cell factor and erythropoietin during lineage commitment of human hematopoietic progenitor cells

The aim of the present study was to determine whether stem cell factor (SCF) and erythropoietin (EPO) act differently on defined subsets of progenitor cells, and if potential differences correlate with the receptor density on each subset. To investigate this possibility directly, we optimized conditions for the identification and purification of homogeneous progenitor cell subpopulations from human bone marrow. Populations containing 40% and 44% colony forming cells (CFCs) with 99% and 95% purity for the granulomonocytic and erythroid lineage, respectively, were sorted on the basis of differential expression of CD34, CD64, and CD71. In addition, a population containing 67% CFCs, of which 29-43% were CFU-MIX, was sorted from CD34hi CD38loCD50+ cells. Purified progenitor cell subsets were compared directly for responsiveness to SCF and EPO using a short-term proliferation assay. Expression of the receptors for SCF and EPO were then examined on each subset using a flow cytometer modified for high- sensitivity fluorescence measurements. The results show that EPO induces extensive proliferation of erythroid progenitor cells, but has no effect on the proliferation or survival of primitive or granulomonocytic progenitors, even when used in combination with other cytokines. The majority of erythroid progenitor cells furthermore stained positively with anti-EPO receptor (EPO-R) monoclonal antibodies, whereas other progenitor cells were negative. SCF alone induced extensive proliferation of erythroid progenitor cells, and had a stronger synergistic effect on primitive than on granulo-monocytic progenitors. In spite of these differences in SCF activity, there were no significant differences in SCF-R expression between the progenitor subsets. These results suggest that the selective action of EPO on erythropoiesis is determined by lineage-restricted receptor expression, whereas there are additional cell-type specific factors that influence progenitor cell responses to SCF.     

Studies on levamisole--induced agranulocytosis

Widespread clinical trials of leavo-tetramisole (levamisole) as an immunopotentiating agent in rheumatoid arthritis, metastatic carcinoma, and immunodeficiency states have been complicated by agranulocytosis (AGC) in 2.5%-13% of patients. Other than a relationship with prolonged high dosage, very little is known regarding the pathogenesis of levamisole-induced AGC. Whereas leukoagglutination was negative, fluorochromatic microgranulocytotoxicity (GCY) tests were positive with serum from 10 of 10 acutely neutropenic patients. The antibody was IgM, reacted with 100% of unrelated granulocytes, but not with T or B lymphocytes. Some sera also reacted with monocytes and the myeloid cell line, K-562. Tests for antigen-antibody complexes or cold autoantibodies were negative. Although clinical evidence strongly suggests a haptene (drug) mechanism, in vitro mixing experiments were also negative. An alternative choice parallels the model of aldomet- induced Coombs'-positive hemolytic anemia. Finally, GCY first became positive 2-3 mo prior to the onset of AGC on two patients, suggesting the possibility of identifying those at risk well before the onset of neutropenia.