A comparison of low back pain patients in the United States and New Zealand: Psychosocial and economic factors affecting severity of disability

One hundred and ninety-eight patients suffering from chronic low back pain seen at the University of Virginia (U.S.) Pain Center and 117 similar patients seen at the Auckland Hospital, Auckland, New Zealand (N.Z.) Pain Clinic completed a self-report questionnaire prior to beginning comparable outpatient treatment programs. Approximately 55% of the sample from each country returned a follow-up questionnaire 1 year later. Analyses of the results indicated that despite nearly similar between-country reports of pain frequency and intensity, the U.S. patients, both at pre- and post-testing, reported greater emotional and behavioral disruption as a correlate of their pain. U.S. patients consistently used more medication, experienced more disphoric mood states, and were more hampered in social-sexual, recreational, and vocational functioning. Patients from both countries demonstrated a nearly equal degree of pre- to post-improvement; however, the relative initial differences favoring the New Zealanders remained constant across both questionnaire administrations. At the onset of treatment, 49% of the U.S. sample and only 17% of the N.Z. patients were receiving pain-related financial compensation. At follow-up, patients from both countries receiving pretreatment compensation were less likely to report a return to full activity, although the relationship appeared more pronounced in U.S. patients. Seemingly, compared to the U.S., the N.Z. compensation-disability system is used less, or for shorter durations of time, resulting in less severe life-style disruption than appears to be the case in the U.S. patients. Seemingly, compared to the U.S., the N.Z. compensation-disability system is used less, or for shorter durations of time. resulting in less severe life-style disruption than appears to be the case in the U.S.     

Isolated xanthomatosis of the small bowel

A case of xanthomatosis of the small bowel is described. Beginning with the proximal jejunum, an 85-cm segment of small bowel was distorted by regularly spaced nodular accumulations of lipid-laden macrophages that expanded the submucosa and muscularis and extended to the serosal surface. The conditions often associated with xanthomatosis were not found in this patient.     

Simulating Dual-Energy X-Ray Absorptiometry in CT Using Deep-Learning Segmentation Cascade

PurposeOsteoporosis is an underdiagnosed condition despite effective screening modalities. Dual-energy x-ray absorptiometry (DEXA) screening, although recommended in clinical guidelines, remains markedly underutilized. In contrast to DEXA, CT utilization is high and presents a valuable data source for opportunistic osteoporosis screening. The purpose of this study was to describe a method to simulate lumbar DEXA scores from routinely acquired CT studies using a machine-learning algorithm.MethodsBetween January 2010 and September 2014, 610 CT studies of the abdomen and pelvis were used to develop spinal column and L1 to L4 multiclass segmentation. DEXA simulation training and validation used 1,843 pairs of CT studies accompanied by DEXA results obtained within a 6-month interval from the same individual. Machine learning–based regression was used to determine correlation between calculated grade (on the basis of vertebrae L1-L4) and DEXA t score.ResultsAnalysis of the t score equivalent, generated by the algorithm, revealed true positives in 1,144 patients, false positives in 92 patients, true negatives in 245 patients, and false negatives in 212 patients, resulting in an accuracy of 82%. Sensitivity for the detection of osteoporosis or osteopenia was 84.4% (95% confidence interval, 82.3%-86.2%), and specificity was 72.7% (95% confidence interval, 67.7%-77.2%).ConclusionsThe presented algorithm can identify osteoporosis and osteopenia with a high degree of accuracy (82%) and a small proportion of false positives. Efforts to cull greater information using machine-learning algorithms from pre-existing data have the potential to have a marked impact on population health efforts such as bone mineral density screening for osteoporosis, in which gaps in screening currently exist.     

A metabolic control mechanism for calcium ion influx that may protect the ventricular myocardial cell

Calcium ion influx into the myocardial cell during the action potential initiates and controls the degree of contraction. The Ca⁺⁺ influx leads to an increase of the myoplasmic free Ca⁺⁺ concentration to about 10⁻⁵ molar for activation of the myofibrils; Ca⁺⁺ may also be released from the sarcoplasmic reticulum by the entering Ca⁺⁺ or by voltage change across its membrane. The inward Ca⁺⁺ current during the action potential plateau traverses the sarcolemma through a separate set of slow cation channels that have some peculiar properties compared to fast sodium ion channels: Slow channels are not sensitive to tetrodotoxin, have lower activation and inactivation potentials and are kinetically slow (slow activation, inactivation and recovery processes). Slow Ca⁺⁺ channels require metabolic energy and are blocked by verapamil, manganese ion, lanthanum ion and acidosis. When the fast Na⁺⁺ channels are blocked by tetrodotoxin or voltage inactivated by 27 millimolar potassium ion, excitability is lost but can be restored by catecholamines and methylxanthines: Propagating slowly rising electrical responses (accompanied by contractions) occur that resemble the plateau of the normal action potential.

Positive inotropic agents such as norepinephrine, theophylline and histamine appear to act by elevating cyclic adenosine monophosphate (AMP) levels and increasing the number of Ca⁺⁺ channels available for voltage activation. Increased cyclic AMP could lead to phosphorylation of a membrane protein constituent of the slow channels by means of a cyclic AMP-dependent protein kinase and adenosine triphosphate (ATP). Thus, the myocardial cell exercises control over the number of available slow channels and, hence, the Ca⁺⁺ influx per impulse. This control mechanism could serve to protect the myocardial cell during periods of regional ischemia by acting to conserve ATP through reduced Ca⁺⁺ influx and contraction, and thus preventing the affected cells from working themselves to death. The Ca⁺⁺ channels in ischemic cells could be made inoperative by decreased ATP, decreased pH or accumulation of some other metabolite.     

The association between the ultrasonography TIRADS classification system and surgical pathology among indeterminate thyroid nodules

Background

A high proportion of cytologically indeterminate, Afirma-suspicious thyroid nodules are benign. The Thyroid Imaging Reporting and Data System was proposed by the American College of Radiology in 2015 to determine appropriate management of thyroid nodules in a standardized fashion. Our aim was to determine the diagnostic value of the Thyroid Imaging Reporting and Data System in cytologically indeterminate and Afirma-suspicious nodules.

Properties of an iodinating enzyme in the ascidian endostyle

An iodinating enzyme was extracted from the endostyles of Molgula manhattensis and Styela clava by a combination of surfactant treatment and trypsin digestion. The solubilized enzyme was partially purified by column chromatography. The enzyme behaves as a large molecular complex (MW ～ 340.000) and is partially hydrophobic in nature. It catalyzes the iodination of tyrosine or protein optimally at a pH of about 7.5. Iodinating activity is inhibited at concentrations of iodide above 0.5 mM. The enzyme is capable of catalyzing the coupling of iodotyrosyl residues in thyroglobulin in vitro, forming T₄ and T₃. It is suggested that the lack of significant iodothyronine formation in the endostyle in vivo is due to the absence of a suitable protein substrate rather than to an enzymatic deficiency.