The effect of secondhand smoke exposure on the association between active cigarette smoking and colorectal cancer

Background  

Studies published prior to 1980 failed to find an association between smoking and colorectal cancer, while subsequent studies reported an association after accounting for a three to four decade initiation period. The aims of this study were to determine the effect of accounting for secondhand smoke (SHS) exposure on the association between smoking and colorectal cancer and to determine the association between SHS and colorectal cancer.     

Mesoatrial shunts for Budd-Chiari syndrome and inferior vena cava thrombosis: angiographic and hemodynamic evaluations

When inferior vena caval obstruction complicates the Budd-Chiari syndrome, conventional portosystemic shunts are not possible. The mesoatrial shunt has been devised to enable portal and sinusoidal decompression in these patients. Findings in 12 patients with Budd-Chiari syndrome and inferior vena caval obstruction in whom a mesoatrial shunt was performed are reported. Preoperative inferior vena cavography with pressure measurements is essential to determine the appropriate shunt procedure. Postoperatively, shunt patency is assessed with superior mesenteric arterial portography. Where possible, transvenous catheterization of the shunt is performed to confirm patency and assess hemodynamic function.     

Expert system-controlled image display

Conventional computer-based medical expert systems deliver advice to physicians as written text. While such advice is useful, it has distinct limitations in a visually oriented discipline such as diagnostic radiology, in which decisions often depend on pattern recognition and appreciation of subtle morphologic features. The authors developed a prototype expert computer system, IMAGE/ICON, which displays groups of images sorted into a series of axes based on different ways in which they may be similar. They may share a common feature, group of features, causes, or clinical setting. IMAGE/ICON may display examples of morphologic variations of a dominant finding or a spectrum of abnormalities seen in an specific disease or group of diseases. The system also assembles a written analysis of key features of a case. Such a tool may be useful as a diagnostic aid or for continuing medical education. It is likely to have particular impact in the form of an intelligent radiologic workstation, as picture archiving and communication systems become available.     

Ulnar nerve injuries of the hand producing intrinsic muscle denervation on magnetic resonance imaging

Muscle and nerve injuries in the hand may be difficult to detect and diagnose clinically. Two cases are reported in which magnetic resonance imaging showed ulnar nerve injury and intrinsic hand muscle denervation. The clinical, anatomical and radiological features of injury to the deep motor branch of the ulnar nerve and associated muscle denervation are discussed and illustrated.     

Pellegrini-Stieda disease

Pellegrini-Stieda disease is a condition occasionally observed on routine radiographic examinations of the knee. A literature survey revealed little in the way of explanation or therapeutic management of this disorder. An overview of this condition with an emphasis on etiological theory and treatment is offered along with two classic radiographic examples.     

Mitochondrial DNA damage in lymphocytes: a role in immunosenescence?

An age-related increase of DNA damage/mutation has been previously reported in human lymphocytes. The high copy number and mutation rate make the mtDNA genome an ideal candidate for assessing damage and to act as a potential biomarker of ageing. In the present study, two assays were developed to evaluate the level of mtDNA(4977) and the accumulation of point mutations with age. A competitive polymerase chain reaction (PCR) methodology incorporating three primers was used to detect and quantify the levels of mtDNA(4977) and a novel heteroduplex reference strand conformational analysis (RSCA) technique was used to analyse the accumulation of point mutations. The assays were applied to an in vitro model of T cell ageing and ex vivo DNA samples from an elderly cohort of subjects and a younger control group. The mtDNA(4977) was detected in all the DNA samples examined but only a very low concentration was observed and no age-related increase or accumulation was observed. No accumulation of point mutations was identified using RSCA within the T cell clones as they were aged or the ex vivo lymphocytes from the elderly cohort. A higher level of variation was observed within the ex vivo DNA samples, verifying the high resolution of RSCA and its ability to identify different mtDNA species, although no correlation with age was observed. The low level of mtDNA damage observed with respect to the ex vivo lymphocyte DNA samples within this study may be due in part to the high turnover of blood cells/mtDNA, which may inhibit the accumulation of genetically abnormal mtDNA that may play a role in immunosenescence. A similar explanation may also apply to the in vitro model of T cell ageing if the vast majority of the cells are replicating rather than entering senescence.     

尿酶检测早期诊断庆大霉素肾脏损害的动物实验与临床研究

采用犬庆大霉素肾中毒模型,结合临床病例,检测尿丙氨酸氨基肽酶、N-乙酰—β—氨基葡萄糖苷酶、γ-谷氨酰转肽酶、乳酸脱氢酶的变化和犬肾超微结构改变。结果显示,治疗剂量庆大霉素对肾脏具有损害作用,中毒量的损害明显加重;处于亚临床期肾病变者,庆大霉素显著加重其毒性损害。检测尿酶的变化可以早期反映出这种肾毒性损害,是一种灵敏的早期监测指标。     

A comparison of polymerase chain reaction and an infectivity assay for human immunodeficiency virus type 1 titration during virus inactivation of blood components

Three examples of human plasma-derived concentrates, intermediate- purity factors VIII and IX, and fibrinogen were spiked with tissue culture-grown human immunodeficiency virus type 1 (HIV-1) strain RF. All examples were freeze-dried and heated at 80 degrees C for 72 hours by using validated production process models. HIV-1 infectivity was measured by a syncytial infectivity assay in C8166 cells and then compared with levels determined by nested HIV polymerase chain reaction (PCR). The infectivity assay demonstrated a reduction index of at least 4.5 log10, while PCR showed an average 1.7 log10. Large amounts of HIV- 1 RNA (10(5)) were still detectable by PCR in samples in which infectivity assays failed to detect any HIV-1. These data suggest that HIV-1 PCR levels do not parallel HIV-1 infectivity levels during virus- inactivation procedures involved in coagulation factor concentrate production. PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal.