Digital chest radiography: effect on diagnostic accuracy of hard copy, conventional video, and reversed gray scale video display formats

Observer performance tests were conducted to compare the effects on diagnostic accuracy of hard copy (film) versus video display and to determine the diagnostic merits of conventional negative ("white bone") versus positive ("black bone") video displays. Subjective preferences were elicited from each observer for each display modality, and diagnostic accuracy was determined with receiver operating characteristic analysis. Digitized chest radiographs were used, including normal and abnormal cases with a variety of subtle abnormalities. The hard copy was printed with a 1,024 X 1,024-matrix by a high-quality drum scanner in conventional white bone format only. The video images were displayed on a 1,023-line monitor (30 Hz, interlaced) in both white bone and black bone formats with fixed window and brightness settings. Most observers preferred hard copy to video, but preferences were sharply divided between white bone and black bone video. Diagnostic accuracy was significantly greater with hard copy than with video display, and the conventional white bone format was significantly superior in accuracy to the black bone display.     

Anterior knee pain: the use of computerized tomography to assess the results of tibial tubercle transfer

Anterior knee pain is a common clinical problem. Patient assessment is difficult. Recently, it has been suggested that the so-called ‘skyline’ views of the patellofemoral joint have no role to play in screening for maltracking and some would suggest that computerized tomography (CT) offers a more accurate method of investigation. The aim of this study was to evaluate the performance of CT in the assessment of three populations: patients suffering form anterior knee pain, patients treated for this condition by tibial tubercle transfer and a control group. The patellofemoral joint was assessed by measuring the trochlear angle, the congruence angle and the patella tilt from the CT images. In summary, the preoperative group had significantly different values of each parameter when compared with other groups but the group that had undergone surgical correction did not demonstrate a significant alteration toward the values of the control group. This study suggests that CT was not useful as either a diagnostic tool or as a indicator of successful surgical outcome.     

Detection of a homozygous four base pair deletion in the protein X gene in a case of pyruvate dehydrogenase complex deficiency

While the presence of a lipoyl-containing protein (protein X) separate from lipoyl transacetylase in the pyruvate dehydrogenase complex (PDC) has been known for some time, until recently only the cDNA for the yeast enzyme has been cloned. We have cloned, sequenced and characterized the cDNA encoding the human protein X and localized the protein X gene to chromosome 11p13. We also report here a new case of protein X deficiency identified immunologically, with decreased activity of PDC and without mutations in the E1alpha subunit or E1beta subunit. We report that the cDNA and gene of this patient for protein X has a homozygous 4 bp deletion, specifically in the putative mitochondrial targeting signal sequence which results in a premature stop codon. This is the first documented case of a molecular defect in pyruvate dehydrogenase protein X.      

Characterisation of renal chloride channel, CLCN5, mutations in hypercalciuric nephrolithiasis (kidney stones) disorders

Mutations of the renal-specific chloride channel (CLCN5) gene, which is located on chromosome Xp11.22, are associated with hypercalciuric nephrolithiasis (kidney stones) in the Northern European and Japanese populations. CLCN5 encodes a 746 amino acid channel (CLC-5) that has approximately 12 transmembrane domains, and heterologous expression of wild-type CLC-5 in Xenopus oocytes has yielded outwardly rectifying chloride currents that were markedly reduced or abolished by these mutations. In order to assess further the structural and functional relationships of this recently cloned chloride channel, additional CLCN5 mutations have been identified in five unrelated families with this disorder. Three of these mutations were missense (G57V, G512R and E527D), one was a nonsense (R648Stop) and one was an insertion (30:H insertion). In addition, two of the mutations (30:H insertion and E527D) were demonstrated to be de novo, and the G57V and E527D mutations were identified in families of Afro-American and Indian origin, respectively. The G57V and 30:H insertion mutations represent the first CLCN5 mutations to be identified in the N-terminus region, and the R648Stop mutation, which has been observed previously in an unrelated family, suggests that this codon may be particularly prone to mutations. Heterologous expression of the mutations resulted in a marked reduction or abolition of the chloride currents, thereby establishing their functional importance. These results help to elucidate further the structure-function relationships of this renal chloride channel.      

IGF-I和hCG对大鼠Leydig细胞葡萄糖转运蛋白基因表达调控研究

背景与目的:研究胰岛素样生长因子-I(Insulin-likegrowthfactor-I,IGF-I)和人绒毛膜促性腺激素(humanChorionicGonadotropin,hCG)对成年大鼠Leydig细胞中葡萄糖转运蛋白(Glucosetransporters,GLUTs)基因表达的影响,为进一步探讨Leydig细胞中睾酮的合成与葡萄糖代谢关系提供依据。材料与方法:采用改良的Klinefelter方法从成年大鼠睾丸中分离获得Leydig细胞,并用反转录-聚合酶链技术检测IGF-I和hCG对Leydig细胞中GLUTs基因表达的调控作用。结果:分离得到纯度为98%的Leydig细胞,与空白对照组相比,hCG可显著增加Leydig细胞中GLUT8基因mRNA的表达,并且此作用具有剂量依赖性与时效性。100ng/mlIGF-I可显著增加Leydig细胞中GLUT8基因mRNA表达,并且IGF-I可和hCG协同作用,显著提高GLUT8基因mRNA表达,该结果与100ng/mlIGF-I和10ng/mlhCG协同作用显著增加睾酮合成的结果相吻合。然而,在大鼠Leydig细胞中,无论是10ng/mlhCG或100ng/mlIGF-I单独作用或同时作用于细胞,都不影响GLUT1和GLUT3基因mRNA水平。结论:在成年大鼠Leydig细胞中,IGF-I和hCG对细胞中GLUT8基因表达的调节作用具有特异性,IGF-I和hCG能协同作用显著提高细胞GLUT8基因mRNA水平,从而增强细胞摄取葡萄糖的能力,可为细胞提供更多的代谢能源,最终增加了Leydig细胞睾酮合成与分泌。     

β-榄香烯抑制大鼠血栓形成及其机理研究

目的;探讨β－榄香烯的抗血栓作用及其机理。方法：采用血栓法观察了大鼠口服β－Ｅｌｅ４０￣１６０ｍｇ／ｋｇ／ｄ１０ｄ后对血栓形成的影响,采用比浊法和放免法分别测定其抗血小板聚集性和ＴＸＡ２及ＰＧＩ２的含量。