The 14q+ chromosome in pre-B-ALL

A child who had acute lymphoblastic leukemia (ALL) associated with an 8;14 chromosome translocation and with a pre-B phenotype is described. The leukemic cells were determined to be pre-B-cells on the basis of intracytoplasmic mu-chain immunoglobulin (cIgM+) and the common-ALL antigen, lack of receptors for sheep erythrocytes, and lack of surface immunoglobulin. The 8;14 translocation is frequently found in patients with Burkitt's lymphoma and in most patients with B-cell ALL and is known to carry a poor prognosis. Thus far, no karyotypes have been reported for patients with pre-B-ALL. The present case indicates that a 14q+ chromosome may provide a proliferative advantage not only to cells with a B-cell phenotype, but also to pre-B-cells. The short survival of our patient also suggests that the 14q+ abnormality and the pre-B phenotype may signal a poor prognosis.     

Acute injury of the ligaments of the knee: magnetic resonance evaluation

Eleven acutely injured knees and 13 normal knees were examined by magnetic resonance imaging (MRI) to assess the value of this modality in detecting acute ligamentous injury of the knee. The presence of torn ligaments in the injured knees was determined by arthroscopy and/or arthrotomy in ten cases and clinical follow-up in one case. The anterior and posterior cruciate ligaments (ACL and PCL) were demonstrated by sagittal spin echo (SE) images through the intercondylar notch (TE = 30 ms; TR = 2,000 ms). The tibial and fibular collateral ligaments (TCL and FCL) were evaluated on coronal SE images (TE = 30 ms, TR = 200 or 530 ms; TE = 120 ms, TR = 2,000 or 2,120 ms). The ACL and PCL were considered torn on MR if they appeared disrupted or were not seen in their normal anatomical positions. The collateral ligaments were considered torn if abnormal high-intensity signal was noted in adjacent soft tissues on TE = 120 ms images or if disruption of a ligament was apparent. Eleven of 15 torn ligaments and 80 of 81 normal ligaments were correctly identified by these criteria. It is concluded that MR imaging may be useful in detecting acute injury of ligaments of the knee.     

Impaired inhibitory G-protein function contributes to increased calcium currents in rats with diabetic neuropathy

There is a growing body of evidence that sensory neuropathy in diabetes is associated with abnormal calcium signaling in dorsal root ganglion (DRG) neurons. Enhanced influx of calcium via multiple high‐threshold calcium currents is present in sensory neurons of several models of diabetes mellitus, including the spontaneously diabetic BioBred/Worchester (BB/W) rat and the chemical streptozotocin (STZ)‐induced rat. We believe that abnormal calcium signaling in diabetes has pathologic significance as elevation of calcium influx and cytosolic calcium release has been implicated in other neurodegenerative conditions characterized by neuronal dysfunction and death. Using electrophysiologic and pharmacologic techniques, the present study provides evidence that significant impairment of G‐protein‐coupled modulation of calcium channel function may underlie the enhanced calcium entry in diabetes. N‐ and P‐type voltage‐activated, high‐threshold calcium channels in DRGs are coupled to mu opiate receptors via inhibitory G(o)‐type G proteins. The responsiveness of this receptor coupled model was tested in dorsal root ganglion (DRG) neurons from spontaneously‐diabetic BB/W rats, and streptozotocin‐induced (STZ) diabetic rats. Intracellular dialysis with GTPgammaS decreased calcium current amplitude in diabetic BB/W DRG neurons compared with those of age‐matched, nondiabetic controls, suggesting that inhibitory G‐protein activity was diminished in diabetes, resulting in larger calcium currents. Facilitation of calcium current density (I(DCa)) by large‐amplitude depolarizing prepulses (proposed to transiently inactivate G proteins), was significantly less effective in neurons from BB/W and STZ‐induced diabetic DRGs. Facilitation was enhanced by intracellular dialysis with GTPgammaS, decreased by pertussis toxin, and abolished by GDPbetaS within 5 min. Direct measurement of GTPase activity using opiate‐mediated GTPgamma[(35)S] binding, confirmed that G‐protein activity was significantly diminished in STZ‐induced diabetic neurons compared with age‐matched nondiabetic controls. Diabetes did not alter the level of expression of mu opiate receptors and G‐protein alpha subunits. These studies indicate that impaired regulation of calcium channels by G proteins is an important mechanism contributing to enhanced calcium influx in diabetes.     

营养药理学--谷氨酰胺、n-3脂肪酸和精氨酸等简介

引言营养不良总是影响外科患者的预后,20世纪初就有人注意到伴有营养不良(以体重降低20%为依据)的消化性溃疡患者术后恢复较慢。后来几十年的研究证明,特殊营养素(如某些维生素和矿物质)缺乏能导致疾病,给予补充则可恢复健康。近年来研究发现,低蛋白血症等营养不良指标与并发症的发生率和死亡率相关。20世纪60年代至70年代的研究表明,对于严重烧伤儿童,只增加营养素(蛋白)的相对浓度而不增加总热卡摄入,可纠正免疫功能低下,提高生存率,改善患儿预后。谷氨酰胺、n-3脂肪酸和精氨酸对疾病的影响引起人们的特别关注,许多学者致力于研究这些营养…     

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.     

Studies on the immunochemistry of human low density lipoproteins utilizing an hemagglutination technique

Hemagglutination is a specific and sensitive technique for investigating the purity of lipoproteins and the immunologic relationships between low density lipoprotein fractions. The S_f 10–400 and S_f 3–9 lipoprotein fractions, isolated from human serum by dextran sulfate-density gradient centrifugation procedure and repurified by centrifugation appeared to contain only lipoprotein antigens since these fractions did not stimulate the production of antibodies against other serum proteins. Cross-absorption experiments with lipoproteins carried on "tanned" cells demonstrated that the S_f 3–9 lipoprotein fraction contains all the antigenic components of the S_f 10–400 lipoprotein fraction together with additional antigenic components not found in the S_f 10–400 lipoprotein fraction. Thus S_f 3–9 and S_f 10–400 lipoprotein fractions are immunologically similar but not identical. Low density lipoproteins contain no antigens in common with the high density lipoproteins. An S_f 3–9 antiserum can be used to detect both S_f 3–9 and S_f 10–400 antigens. The S_f 3–9 lipoprotein fraction used as an antigen will detect antibodies against both S_f 3–9 and S_f 10–400 lipoprotein fractions. The S_f 3–9 and S_f 10–400 antisera did not contain immune antibodies against erythrocytes of the different blood groups or against sheep, guinea pig, dog, calf, pig, horse, and chicken erythrocytes. Normal subjects and subjects with recent myocardial infarctions had no circulating autoantibodies against the S_f 3–9 and S_f 10–400 lipoprotein fractions.