Shoulder Position During Magnetic Resonance Arthrogram Significantly Affects Capsular Measurements

PurposeTo determine whether change in shoulder position between internal rotation (IR) and external rotation (ER) during magnetic resonance arthrography (MRA) affects previously defined capsular measurements and to determine the utility of rotation in the diagnosis of instability.MethodsA retrospective study was conducted of patients who received a shoulder MRA with humeral IR and ER views. Patients with an arthroscopically confirmed diagnosis of instability and those with clinically stable shoulders, no history of instability, and no MRA findings of instability were identified and compared. Humeral rotation, glenoid retroversion, humeral head subluxation, capsular length, and capsular area using axial sequences of IR and ER views were recorded. Analysis compared IR, ER, and Δ capsular measurements between groups using independent t tests and univariate and multivariate regression.ResultsThirty-one subjects who were diagnosed with instability were included, along with 28 control subjects. Capsular length, capsular area, and humeral subluxations were significantly greater with ER compared with IR views (P < .001, P < .001, P < .001). Patients with instability displayed greater ER capsular length (P = .0006) and ER capsular area (P = .005) relative to controls. Multivariate logistic regression identified age, weight, sex, ER capsular length, and retroversion to be significant predictors of instability. ER capsular length independently predicts instability with 86% sensitivity and 84% specificity. Interobserver reliability using the intraclass correlation coefficient was rated good or excellent on all measurements.ConclusionVariance in humeral rotation during shoulder MRA significantly affects capsular measurements. Rotational views increase the utility of capsular measurements when assessing for instability, particularly capsular length and capsular area. The implementation of ER positioning enhances the ability to examine capsular changes of the shoulder joint and can assist in the diagnosis of instability.Level of EvidenceIII, retrospective comparative study     

On the secondary stability of coated cementless hip replacement: parameters that affected interface strength

Unlike primary stability of coated cementless implants, their secondary stability has been poorly studied. This paper considers some theoretical aspects of the secondary stability of a coated cementless hip implant in a human femur. The bone is separated from the implant by a thin layer of microscopic peaks and troughs formed on the surface of the coating. The size of the peaks and troughs is very small compared with the macrosize of the implant stem and bone in contact. The study of the bone–stem contact by direct application of the finite element method is prohibitively costly. A two-scale asymptotic homogenisation procedure that takes into account the microgeometry of the interface layer and mechanical properties of bone and the implant material is applied to obtain effective, homogenised contact parameters. These parameters can be used in finite element analyses involving smooth interfaces, which require hundreds of times fewer finite elements. With the homogenisation technique and finite element analyses for a simplified design, two parameters were found to be most important—the normal contact stiffness and the friction coefficient. They both increase several times as bone grows into the rough surface of the implant and mineralises, thus providing a stronger interface and resulting in reduced micromotions.     

Glutamine oxidation and utilization by rat and human oesophagus and duodenum

The rates of utilization and oxidation of glutamine and glucose by oesophageal and duodenal tissues have been investigated in both rats and human subjects. In the rat, glutamine utilization by oesophageal tissue was 2-3-fold lower than that in the duodenum, and this substrate contributed less than 10% to the total oxidative metabolism of the tissue, even when glutamine was the only substrate provided. In contrast, rat duodenal tissue derived about 34% of the total CO2 production from glutamine-C, and this contribution was not suppressed by the addition of either glucose or a mixture of the other substrates. Rates of glucose utilization and oxidation by the duodenum were lower than those for glutamine, and were significantly (P < 0.001) suppressed by addition of glutamine. In both oesophageal and duodenal tissues, less than 10% of the glutamine-C utilized was fully oxidized, approximately 60-70% was converted to glutamate, and 30-40% to alanine. Results obtained using human biopsy tissue samples were similar to those observed in the rat. Glutamine oxidation contributed 34 (SD 4)% of the total CO2 production by the duodenal tissue, but only 8 (SD 4)% to oesophageal tissue oxidation. The findings suggest that glutamine is not an important or preferred fuel for oesophageal tissue, whereas it is for duodenal tissue. Thus, these tissues can be expected to respond differently to glutamine administration.     

Heritability of the symptoms of benign prostatic hyperplasia and the roles of age and zonal prostate volumes in twins

OBJECTIVES: Both benign prostatic hyperplasia and lower urinary tract symptoms (LUTS) have been shown to increase with age in men, but a causal relationship between prostate volume and symptoms has not been established. This study had two aims, to investigate the inter-relationships of age, symptoms, and various zonal measurements in the prostate and to assess the impact of heritable influences on symptom score. METHODS: Eighty-three monozygotic twin pairs and 83 dizygotic twin pairs were studied to determine age and LUTS as assessed by the American Urological Association symptom score. Their prostate volumes (total, transition zone, and peripheral zone) were measured by transrectal ultrasound. RESULTS: There was significant evidence of pairwise correlation between transition zone and symptom score (P = 0.04) and between age and symptom score (P = 0.03). Age also showed significant correlation with all volume measurements. Heritability appears to account for 82.6% of the variability in symptom score in men older than 50 years. CONCLUSIONS: This study provides evidence that age and transition zone volume play a role in LUTS, but also that their influence is not strong. Estimates of heritability suggest that hereditary factors contribute substantially to LUTS.     

Inhibition of allergen-induced pulmonary responses by the selective tryptase inhibitor 1,5-bis-[4-[(3-carbamimidoyl-benzenesulfonylamino)-methyl]-phenoxy]-pen tane (AMG-126737)

Emerging evidence suggests that mast cell tryptase is a therapeutic target for the treatment of asthma. The effects of this serine protease are associated with both pathophysiologic pulmonary responses and pathologic changes of the asthmatic airway. In this study, the tryptase inhibitor 1,5-bis-[4-[(3-carbamimidoyl-benzenesulfonylamino)-methyl]-p henoxy]-pentane (AMG-126737) was evaluated for its pharmacologic effects against allergen-induced airway responses. AMG-126737 is a potent inhibitor of human lung mast cell tryptase (Ki = 90 nM), with greater than 10- to 200-fold selectivity versus other serine proteases. Intratracheal administration of AMG-126737 inhibited the development of airway hyperresponsiveness in allergen-challenged guinea pigs with an ED50 of 0.015 mg/kg. In addition, the compound exhibited oral activity in the guinea pig model. The in vivo activity of AMG-126737 was confirmed in a sheep model of allergen-induced airway responses, where the compound inhibited early and late phase bronchoconstriction responses and the development of airway hyperresponsiveness. These results support the proposed role of tryptase in the pathology of asthma and suggest that AMG-126737 has potential therapeutic utility in this pulmonary disorder.     

Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency—diagnosis,plasma carnitine fractions and management in a further patient

Long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD), the third enzyme of the mitochondrial -oxidation pathway, carries out the dehydrogenation of 3-hydroxyacyl-CoA compounds of 12–18 carbon length. To date only nine cases of LCHAD deficiency have been documented. We report a further patient who as a neonate developed non-specific gastro-intestinal symptoms and at 5 months of age cardiomyopathy, recurrent hypoketotic hypoglycaemia and gross alterations of plasma carnitine fractions. Dietary management with medium chain triglycerides led rapidly to clinical improvement. There was a close correlation between the clinical condition, plasma carnitine fractions and cardiac function. At 2 years of age she is developing normally.     

Rights and respect. Legal and ethical issues challenge today's mental healthcare professionals

The special circumstances of patients in mental health facilities often make questions concerning patient autonomy, freedom of choice, and consent to treatment even more complex than they are in other contexts. Individual facilities need to identify the ethical issues they are likely to encounter and create policies that address them effectively. The advent of managed care has created unprecedented access problems for mental healthcare providers. In many cases patients must be proven dangerous to themselves or others before they can be admitted for emergency care; because it is difficult to prove this, many persons go without needed treatment. The high costs of care and prejudices against persons with mental illness also create ethical problems. The necessity of performing clinical evaluations raises important ethical issues as well. Care givers evaluating someone at the request of a school, employer, or court should be sensitive to the possible consequences of their evaluation. They should also restrict their diagnoses to their area of competency and inform clients of the purpose of the evaluation, its possible consequences, and the limits of its confidentiality. Mental health professionals must also respect patients' rights to informed consent and understand the issues of voluntary or involuntary admissions. In addition, care givers should be aware of the various issues created by the need to occasionally control patients' behavior. Finally, for mental healthcare facilities, it is essential to establish an ethics committee to address these issues.