Reliability of the acetabular teardrop as a landmark

Summary This study investigated the effect of tilt and observer reliability on radiographic measurements of the position of a prosthetic acetabular cup in seven dry bone pelves using the teardrop as a landmark. Coronal or sagittal tilt of more than five degrees was easily recognisable and there was effectively no observer variation in the measurements up to this limit. In addition, 90 out of 100 randomly selected antero-posterior pelvic radiographs from an outpatient department were not significantly rotated and 93 demonstrated a clearly defined teardrop. Measurements about the teardrop on routine radiographs are therefore sufficiently accurate to allow assessment of prosthetic position.

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La valeur du sourcil cotyloidien comme repère d'analyse radiologique

Résumé Cette étude, conduite sur 7 bassins secs, apprécie l'effet de l'inclinaison du bassin sur la qualité de l'analyse radiographique de la position d'une cupule prothétique de hanche en utilisant le sourcil cotyloïdien comme repère. Une inclinaison du bassin dans les plans coronal et sagittal est aisément détectable et il n'existe pas de variation d'analyse entre les différents observateurs en dessous de 5° d'inclinaison. De plus, sur 100 radiographies antéro-postérieures de bassin choisies au hasard dans les dossiers de consultation, 90 avaient été réalisées sans incidence particulièrement adaptée et l'on pouvait repérer facilement le sourcil sur 93% d'entre elles. Les mesures faites sur des radios de routine sont donc suffisamment précises pour permettre l'évaluation de la position d'une prothèse à partir du sourcil cotyloïdien.

     

Hypoxic pulmonary vasoconstriction is heterogeneously distributed in the prone dog

Hypoxic pulmonary vasoconstriction (HPV) is thought to protect gas exchange by decreasing perfusion to hypoxic regions. However, with global hypoxia, non-uniformity in HPV may cause over-perfusion to some regions, leading to high-altitude pulmonary edema. To quantify the spatial distribution of HPV and regional PO2 (PRO2) among small lung regions (approximately 2.0 cm3), five prone beagles (approximately 8.3 kg) were anesthetized and ventilated (PEEP approximately 2 cm H2O) with an F1O2 of 0.21, then 0.50, 0.18, 0.15, and 0.12 in random order. Regional blood perfusion (Q), ventilation (VA) and calculated PRO2 were obtained using iv infusion of 15 microm and inhalation of 1 microm fluorescent microspheres. Lung pieces were clustered by their relative blood flow response to each F1O2. Clusters were shown to be spatially grouped within animals and across animals. Lung piece resistance increased as PRO2 decreased to 60-70 mmHg but dropped at PRO2's < 60mmHg. Regional ventilation changed little with hypoxia. HPV varied more in strength of response, rather than PRO2 response threshold. In initially homogeneous VA/Q lungs, we conclude that HPV response is heterogeneous and spatially clustered.     

Tetraspanins: molecular organisers of the leukocyte surface

Tetraspanins are a large superfamily of cell surface membrane proteins characterised by their four transmembrane domains. They are expressed in a wide variety of cell types and have functional roles in processes, such as cellular adhesion, motility, activation and tumour invasion. Leukocytes express 相似文献   

Hepatocellular carcinomas show abnormal expression of fibronectin protein.

Fibronectin plays an important role in cell-to-cell adhesion, cell migration, and cell signaling. In the liver, fibronectin expression has been studied primarily as a component of the extracellular matrix, but little information is available on the expression of fibronectin protein in the neoplastic cells of hepatocellular carcinomas (HCCs). Twenty-four surgically resected HCCs were immunostained with fibronectin. Tumor and normal liver tissues were concurrently analyzed in all cases, and expression in the tumor was evaluated in comparison to the nonneoplastic liver. The average age at resection was 54 +/- 18 years for the 18 men and 6 women. Twenty-one of the cases were classic HCCs including 6 cases that were well differentiated, 12 cases moderately differentiated, and 3 cases poorly differentiated. The remaining 3 cases were moderately differentiated fibrolamellar carcinomas. In the normal liver, fibronectin labeled the sinusoids and weakly to moderately stained the cytoplasm of hepatocytes. In HCCs, 15/24 showed overexpression of fibronectin in the cytoplasm, 8/24 showed no change from the nonneoplastic liver, and one case showed decreased cytoplasmic staining. In addition, an abnormal membranous staining pattern was noted in 16/24 HCCs. In contrast to the HCCs, none of the three fibrolamellar carcinomas showed increased cytoplasmic or membranous staining. Excluding fibrolamellar carcinoma, increased cytoplasmic staining and/or an abnormal membranous staining was noted in 19/21 (90%) of HCCs. Fibronectin shows abnormal cytoplasmic and/or membranous staining in the majority of HCCs. The implications of fibronectin overexpression are uncertain but may reflect a critical step in tumor genesis.     

Localization of the disulfide bridges of human histocompatibility antigens.

Both papain-solubilized and detergent-solubilized human histocompatibility antigens have been treated with NTCB (2-nitro-5-thiocyanatobenzoic acid) which cleaves these molecules at cysteine residues. A study of the fragment produced has made it possible to deduce the size and location of the two disulfide loops in these molecules. The sizes of the two loops in HLA-B7 and in the mixture HLA-B7 + 12 are about 5100 and 6600 daltons, a size similar to that of the disulfide loops found in immunoglobulins. The disulfide loops in HLA-A2 may be smaller in size. The two loops are located in middle regions of these molecules; neither the N-terminal nor the C-terminal regions contain disulfide loops.     

Variation in peripheral blood T cell subsets in serial assays

No significant differences were found in the T cell subsets of fresh and frozen peripheral blood mononuclear cells (PBM) from six healthy donors analysed with the Ortho series of monoclonal antibodies and a fluorescence-activated cell sorter. Analysis of replicates of cryopreserved PBM showed that considerably higher variation in T cell subsets occurred when samples were assayed in serial assays than when the samples were analysed together under the same conditions. These results indicate that errors introduced into a longitudinal study by serial analysis of samples may be reduced if samples are cryopreserved and subsequently thawed and analysed together at the end of the study.