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Background Anterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: 1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model, 2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. Hypothesis We hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. Methods A dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of center of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). Results Mean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94 mm ± 5.24 (SD) (95%Confidence Interval: 3.25–4.27) and 5.14 mm ± 3.07 (95%CI: 1.9-2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol, mean error was reduced to 3.0 mm ± 1.9 (95%CI: 1.16–1.53) and 4.3 mm ± 4.3 (95%CI: 2.67–351) on the first attempt, and to 1.7 mm ± 1.9 (95%CI: 1.15–1.52) and 2.1 mm ± 1.4 (95%CI: 0.87–1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19–0.68) and 0.59 (95% CI: 0.44–0.79) using the standard protocol, to 0.88 (95%CI: 0.61–0.91) and 0.9 (95%CI: 0.56 - 0.92) using the novel protocol. Conclusions There is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. Level of evidence III, in vitro study comparing diagnostic tools.

Objective: Familial hypobetalipoproteinemia (FHBL) is characterized by mutations in APOB, the majority of these causing protein truncations, and low plasma levels of apolipoprotein (apo) B. The hypobetalipoproteinemia may be due to enhanced clearance and possibly reduced production of apoB-containing lipoproteins;the mechanism may depend on the length of the apoB truncation. We studied fasting lipoprotein metabolism in an FHBL subject heterozygous for a mutation causing a truncated apoB, apoB-80. Design and Methods: Very low density lipoprotein (VLDL)-, intermediate density lipoprotein (IDL)-, and low density lipoprotein (LDL)-apoB kinetics were determined in the fasting state using stable isotope methods and compartmental modeling. Results: Compared with lean normolipidemic controls the apoB-80 FHBL subject had an elevated VLDL-apoB fractional catabolic rate and lower LDL production. ApoB production rates and IDL- and LDL-apoB fractional catabolic rates were not different. Conclusion: FHBL subjects heterozygous for a mutation truncating apoB to 80% of full-length are able to produce VLDL-apoB normally, but have rapid clearance of these particles, resulting in low levels of circulating apoB. (C) 2016 The Canadian Society of Clinical Chemists. Published by ELSEVIER. All rights reserved.

Objective. The aim of this study was to examine age, gender, and segmental trends in thoracic vertebral body shape, utilising thoracic spine magnetic resonance images involving an age range spanning the life span. Design. A quantitative, cross-sectional, retrospective study design involving a sample of convenience. Background. Thoracic vertebral shape data are commonly derived from radiographic resources. The non-ionising properties of magnetic resonance imaging and availability of digital data for image analysis suggest potential for MR-based morphometric studies. For the thoracic spine, there is limited vertebral shape data on males, while few studies have examined the pattern of age-related changes across the life span. Methods. Morphometry was performed on 220 mid sagittal T1-weighted MR images using image analysis software. Three indices of vertebral shape were utilised: the antero-posterior height ratio or anterior wedge index, mid-posterior height ratio or biconcavity index, and ratio of posterior vertebral height to mid antero-posterior diameter or compression index. Results. Different segmental patterns were noted for the vertebral shape indices. Significantly lower mean values were noted in males for the compression index. Age trends were significant, with a linear age-related decline demonstrated for the anterior wedge and biconcavity indices, and a quadratic trend noted for the compression index. Conclusions. Thoracic vertebral body shape may be uniquely described using specific shape indices, for examining various segmental, gender and age-associated changes. Relevance These results suggest the importance of defining specific reference criteria for thoracic vertebral body shape indices, particularly age-related data encompassing a wide age range. Magnetic resonance studies enable interpretation of vertebral shape data in relation to the wide spectrum of pathologies afflicting the thoracic spine, without the concerns of ionising radiation.

We aimed to examine the effect of genetic poly- morphisms of apolipoprotein B-100 (apoB) signal peptide and apolipoprotein E (apoE) on the hepatic secretion of very low density lipoprotein (VLDL) apoB in 29 men with visceral obesity. We studied apoB secretion using a primed (1 mg/kg), constant (1 mg/kg/h) intravenous infusion of (1- 13 C)leucine. The isotopic enrichment of VLDL apoB was determined using gas chromatography-mass spectrometry (GCMS). A multi-compartmental model was used to esti- mate the fractional turnover rate of VLDL apoB. Genotypes for the apoB signal peptide length polymorphism, 27 amino acid (SP27) and 24 amino acid (SP24), and apoE genotypes were determined using polymerase chain reaction. In sub- jects who were not apoE2 carriers and were homozygous for the SP27 of the apoB signal peptide, the hepatic secretion of VLDL apoB was significantly higher than in subjects who were not apoE2 carriers and were either heterozygous or homozygous for the SP24 allele (31.3 6 11.8 mg/kg fat-free mass/day, n 5 8 vs. 16.9 6 12.2 mg/kg fat-free mass/day, n 5 13, P 5 0.01). In subjects who were not apoE4 carriers and were either heterozygous or homozygous for the apoB SP24 allele, the hepatic secretion of VLDL apoB was significantly lower than in subjects who were not apoE4 carriers and were homozygous for the SP27 allele (15.8 6 12.9 mg/kg fat-free mass/day, n 5 13 vs. 27.4 6 11.5 mg/kg fat-free mass/day, n 5 7, P 5 0.03). The data suggest that in men with visceral obesity, the apoB signal peptide and apoE gen- otypes appear to be involved in the hepatic secretion of apoB.— Riches, F. M., G. F. Watts, F. M. van Bockxmeer, J. Hua, S. Song, S. E. Humphries, and P. J. Talmud. Apolipo- protein B signal peptide and apolipoprotein E genotypes as determinants of the hepatic secretion of VLDL apoB in obese men. J. Lipid Res. 1998. 39: 1752-1758.