In vivo intrarater and interrater precision of measuring apparent bone mineral density in vertebral subregions using supine lateral dual-energy x-ray absorptiometry.

Analysis of apparent bone mineral density (BMD) in the lumbar spine is commonly based on anteroposterior (AP) scanning using dual-energy X-ray absorptiometry (DXA). Although not widely used, clinically important information can also be derived from lateral scanning. Vertebral bone density, and therefore strength, can may vary in different subregions of the vertebral body. Therefore, subregional BMD measurements might be informative about fracture risk. However, the intrarater and interrater precision of in vivo subregional BMD assessments from lateral DXA remains unknown. Ten normal, young (mean: 24 yr) and 10 older (mean: 63 yr) individuals with low BMD were scanned on one occasion using an AP/lateral sequence. Each lateral scan was reanalyzed six times at L2 by three raters to determine the intrarater and interrater precision in selecting seven regions of interest (subregions). Precision was expressed using percentage coefficients of variation (% CV) and intraclass correlation coefficients (ICC). Intrarater precision ranged from ICC(1,1) 0.971 to 0.996 (% CV: 0.50-3.68) for the young cohort and ICC(1,1) 0.934 to 0.993 (% CV: 1.46-5.30) for the older cohort. Interrater precision ranged from ICC(2,1) 0.804 to 0.915 (% CV: 1.11-2.35) for the young cohort and ICC(2,1) 0.912 to 0.984 (% CV: 1.85-4.32) for the older cohort. Scanning a subgroup of participants twice with repositioning was used to assess short-term in vivo precision. At L2, short-term in vivo precision ranged from ICC(1,1) 0.867 to 0.962 (% CV: 3.38-9.61), at L3 from ICC(1,1) 0.961 to 0.988 (% CV: 2.02-5.57) and using an L2/L3 combination from ICC(1,1) 0.942 to 0.980 (% CV: 2.04-4.61). This study demonstrated moderate to high precision for subregional analysis of apparent BMD in the lumbar spine using lateral DXA in vivo.     

Specific MR imaging of human lymphocytes by monoclonal antibody-guided dextran-magnetite particles.

Human lymphocytes were labeled with biotinylated anti-lymphocyte-directed monoclonal antibodies, to which streptavidin and subsequently biotinylated dextran-magnetite particles were coupled. This labeling resulted in a strong and selective negative contrast enhancement of lymphocyte suspensions at 2.0 T, caused predominantly by the specific increase of R2 with a small but significant specific increase of R1. The R1 was found to decrease with increasing field strength. The immunolabeling procedure described here may be used for the selective signal depletion of target cells in MR imaging.     

A Bayesian approach to aid in formulary decision making: incorporating institution-specific cost-effectiveness data with clinical trial results.

Pharmacy and therapeutics committees commonly cite a lack of generalizability as a reason for not incorporating cost-effectiveness information into decision making. To address this concern, many committees undertake site-specific economic evaluations, which are often limited by small sample sizes and nonrandomized designs. We show how 2 complementary approaches were used to minimize these limitations in an economic evaluation of abciximab at 1 institution. Using a propensity score methodology, we selected patients who did not receive abciximab for the comparison cohort. Then, we adopted a Bayesian, hierarchical, random-effects model to integrate site-specific and clinical trial data. We applied the posterior distributions of effectiveness with local cost data in a traditional decision-analytic model. In 74% of the simulations, abciximab was cost-effective at 1 institution at the $50,000 per life year saved threshold, assuming a 50:50 split of patients undergoing coronary stenting and angioplasty. Among patients undergoing coronary stenting, the cost-effectiveness ratio of the addition of abciximab was at or below the $50,000 per life year saved threshold in 66.0% of the simulations.     

Femoroacetabular impingement in 45 professional athletes: associated pathologies and return to sport following arthroscopic decompression

Femoroacetabular impingement (FAI) occurs when an osseous abnormality of the proximal femur (cam) or acetabulum (pincer) triggers damage to the acetabular labrum and articular cartilage in the hip. Although the precise etiology of FAI is not well understood, both types of FAI are common in athletes presenting with hip pain, loss of range-of-motion, and disability in athletics. An open surgical approach to decompressing FAI has shown good clinical outcomes; however, this highly invasive approach inherently may delay or preclude a high level athlete’s return to play. The purpose of this study was to define associated pathologies and determine if an arthroscopic approach to treating FAI can allow professional athletes to return to high-level sport. Hip arthroscopy for the treatment of FAI allows professional athletes to return to professional sport. Between October 2000 and September 2005, 45 professional athletes underwent hip arthroscopy for the decompression of FAI. Operative and return-to-play data were obtained from patient records. Average time to follow-up was 1.6 years (range: 6 months to 5.5 years). Forty two (93%) athletes returned to professional competition following arthroscopic decompression of FAI. Three athletes did not return to play; however, all had diffuse osteoarthritis at the time of arthroscopy. Thirty-five athletes (78%) remain active in professional sport at an average follow-up of 1.6 years. Arthroscopic treatment of FAI allows professional athletes to return to professional sport.     

Management of the facial nerve in skull base surgery.

The facial nerve presents a significant obstacle to adequate surgical exposure of lesions involving the skull base. The evolution of various surgical approaches to the jugular foramen, petrous apex, and lateral facial approaches to the skull base aimed at preserving the seventh cranial nerve are reviewed. Methods and techniques in management of the intratemporal and extratemporal facial nerve are discussed.     

Pharmacokinetics of the acetylcholinesterase oxime reactivator, HI-6, in rhesus monkeys (Macaca mulatta): effect of atropine, diazepam, and methoxyflurane anesthesia

The pharmacokinetics of the bispyridinium oxime HI-6 (CAS reg. no. 34433-31-3; 1-(((4-aminocarbonyl)pyridinio)methoxy)methyl)-2-[hydroxy i mino)methyl)- pyridinium dichloride) was investigated in rhesus monkeys (Macaca mulatta). The effects of methoxyflurane anesthesia, administration of atropine with and without diazepam were determined on the serum half-life (t1/2), clearance rate (CL), and the volume of distribution (Vd) following intramuscular (IM) administration of HI-6 (30 mg kg-1). The control t1/2, CL and Vd of HI-offere 27 min, 8.6 ml min-1 kg-1 and 0.34 l kg-1, respectively. These parameters were unaffected by the co-administration of either atropine (0.5 mg kg-1, IM) or atropine and diazepam (0.5 mg kg-1, IM + 0.2 mg kg-1 IV, respectively). Methoxyflurane anesthesia resulted in a significant increase in the HI-6 t1/2 to 61 min concomitant with a decrease in the CL to 4.1 ml min-1 kg-1 with no change in the Vd. The increase in the t1/2 of HI-6 in methoxyflurane anesthetized monkeys is probably the result of a decrease in the clearance rate and, thus, excretion of HI-6 by the kidneys.