The diagnosis of knee motion limits, subluxations, and ligament injury

The clinical diagnosis of knee ligament injuries requires the clinician to: 1) estimate the abnormal motion limits that occur in one or more of the six degrees of freedom that comprise three-dimensional motion; 2) determine the abnormal position (subluxation) of the medial and lateral tibiofemoral compartments; and 3) precisely define the anatomical structures injured and degree of that injury. To determine the clinician's ability to perform these tasks, we evaluated 11 knee surgeons' clinical examination for knee instability. The positions and motions included were measured in right-left cadaveric knees by a three-dimensional instrumented spacial linkage. We compared the clinicians' estimate of knee motion limits and subluxations with the actual measured values. Before and after the clinicians' examination, the three-dimensional limits of knee motion were measured in the knees in the laboratory under defined loading conditions. Also, in one knee, the ACL and superficial medial collateral ligament were cut and the examiners, none of whom were informed of the sectioning, were asked to arrive at a diagnosis. The results for all of the clinical instability tests were similar. There was wide variability between examiners in the starting position of knee flexion and tibial rotation and in the amount of tibial translation and rotation induced. Although some examiners displaced the knee to the maximal displacement limits obtained in the laboratory, others did not, by a substantial margin. This suggests a wide variation in the loads applied by examiners to the knee joint during the tests.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skeletal muscle blood flow in vivo: detection with rubidium-82 and effects of glucose, insulin, and exercise

In order to assess the effects of glucose, insulin, and exercise on skeletal muscle blood flow in vivo, we measured positron emission from the thigh muscle of anesthetized rabbits after simultaneous aortic bolus injection of 82Rb and radiolabeled microspheres (15 micron diameter). Estimates of flow with 82Rb were based on first-pass regional extraction of 82Rb by skeletal muscle. Flow estimates were made serially as a function of variations in plasma glucose and insulin and changing the muscle contractile state by electrical stimulation. Flow ranged from 3.1 ml/min/100 g at rest to 71 ml/min/100 g during stimulation. There was good agreement between the two methods of flow measurement over the entire range of flows (r = 0.96 at a slope of 0.90). Flow measured by either method did not vary significantly from baseline over a range of plasma glucose from 5 to 30 mM and plasma insulin from 0 to 20 microU/ml. When flow was increased up to 20-fold by electrical stimulation there was a decrease in extraction of 82Rb proportional to the increase in flow. However, at pharmacologic levels of insulin (greater than 150 microU/ml) flow was increased twofold as measured by radiolabeled microspheres, but not as measured by rubidium. There was no apparent decrease in extraction of 82Rb with high insulin. The discrepancy between the microsphere measured flow and rubidium measured flow with high plasma insulin levels can be explained by the assumption that the expected decrease in the extraction fraction was counteracted by an increase in Na+/K+-ATPase activity. It is concluded that the first-pass flow model gives valid estimates of skeletal muscle blood flow in vivo with 82Rb, provided that plasma insulin levels are normal.     

The effects of walking,running, and shoe size on foot volumetrics

Objectives. The objective of this study was to investigate the effects of walking and running on foot volumetrics, and its relationship between measured foot size and preferred shoe size.Design. This study was a single-group, repeated measures design. Twenty-eight physical therapy students participated in the testing.Methods. Following 10 min of supine rest, a pre-exercise volumetric measurement of the right leg was obtained. Shoe size and foot length measurements were taken. Subjects were randomly assigned to a treatment condition (walking or running). The treadmill speed was set at a comfortable pace for each participant during exercise. Foot volume measurements were taken after the exercise. Subjects returned the next week to participate in the second condition.Results. Paired t-tests were used to compare differences in outcome variables. Significant increases in fluid volumes were noted within groups after walking (2%) and running (3%) and between groups in the post-walk and post-run values (1.7%). A weak positive correlation was noted between changes in volume during running and the measured difference between foot size and shoe size (r=0.39; p=0.038).Conclusions. Treadmill running for 10 min may lead to significantly greater foot volume compared to treadmill walking for the same period. Results also demonstrate that the greater the measured difference between shoe size and foot size, the greater the foot volume after running.     

Habitual physical activity, strenuous exercise, and salivary immunoglobulin A levels in young adults: the Amsterdam Growth and Health Study

Secretory IgA (S-IgA) levels in stimulated salvia were measured before and after a maximal treadmill test in a population of 175 young adults (84 men, 91 women). Habitual physical activity levels of this population were measured by a standardized interview, and scores were obtained for the amount of time and intensity of sports activities and total activity. Before the maximal treadmill test, men and women showed no statistically significant differences in the salivary concentrations of S-IgA, but the concentration of S-IgA in women decreased and in men increased statistically significantly (P less than 0.05) after the treadmill test. Only women showed a significant correlation between absolute values of S-IgA and the weekly amount of time spent on sports activity measured by a standardized interview expressed in minutes per week.     

人工、半自动及自动方法测量肺实性结节直径和体积的一致性研究

目的:评估人工测量方法、基于计算机辅助诊断（CAD）的半自动测量方法和基于人工智能的全自动测量方法在肺实性结节直径和体积测量中的一致性。方法:回顾性分析2018年7月至2020年4月四川省肿瘤医院接受肺癌筛查的165例受检者的临床和低剂量CT（LDCT）资料。选取每例受检者直径最大的结节作为研究对象,由1名初级和1名高...     

Comparative analysis of arterial oxygen saturations during exercise by pulse oximetry, photometric measurements, and calculation procedures

Pulse oximetry allows non-invasive monitoring of arterial oxygen saturation (SO2). To study the validity of pulse oximetry, comparative measurements were performed. During exhaustion limited exercise SO2-values measured by pulse oximetry (SO2puls), calculated SO2-values (algorithms of Kelman, Severinghaus, and Siggaard-Andersen--SO2calc), and as "golden standard" photometric measured SO2-values (SO2meas) were compared. Fourteen triathletes performed a stepwise cycling exercise test in the supine position. SO2calc was determined on the basis of capillary actual blood gas values. SO2puls was measured continuously with a finger probe attached to the second finger. The SO2puls- and SO2calc-values differed from the SO2meas-values (p less than 0.05); however, the differences were of no clinical relevance. Performing linear regression analysis, only SO2puls correlated significantly (r = 0.47, p less than 0.001) with SO2meas. Pulse oximetry is able to replace invasive measurements of arterial oxygen saturation in athletes. It is superior to SO2-calculations and permits reliable, valid and non-invasive continuous monitoring of SO2.     

Measurement of Coster-Kronig vacancy transfer factor for L3 subshell X-rays of Au, Hg, Pb, Tl, Bi, Th and U at 59.5 keV.

The Coster-Kronig vacancy transfer factors were measured for L3 subshell X-rays using the experimental L(alpha) X-ray production cross section, the fraction of L(alpha) X-rays, L3 subshell fluorescence yield and L3 shell photoionization cross section. The obtained experimental results were compared with the theoretical values. It showed that the agreement between the present experimental and theoretical results was very good.     

Evaluation of radiation dose, focal spot, and automatic exposure of newer film-screen mammography units

Fifteen recently introduced mammographic units representing eight different models and manufacturers were evaluated to see whether the equipment performance equaled claims made by the manufacturers. Focal-spot size was measured by pinhole and slit methods. Eight automatic exposure control systems on five models were tested by measuring the optical density produced by imaging at 28 and 30 kVp, with and without a grid and with test objects of varying thicknesses of BR12 epoxy material. Comparable mean glandular dose for a 4-cm-thick BR12 test object was measured for 13 of the units under manual or automatic exposures. Nominal focal-spot size was larger than stated for six of the 15 large focal spots and for seven of the 12 microfocal spots. Comparable doses under automatic exposure control varied more than 100% between units from different manufacturers, while the doses of units from the same manufacturer varied less than 20%. Automatic exposure control systems were operational in eight of the 15 units, but four of these eight were found to be out of calibration. There are considerable performance variations that need to be evaluated before acceptance and use of new mammographic equipment.     

Erythrocyte, plasma, and blood volume of healthy young men.

Insufficient data are readily available concerning the vascular fluid volumes of healthy young men. The primary purpose of this study was to develop a normative database for the erythrocyte volume, plasma volume, and blood volume of healthy young men. The secondary purposes were to relate these vascular fluid volumes to the person's body size and physical fitness level and to develop equations that enable their prediction. Fifty-one male soldiers with a mean age of 22 (range 18-35) yr and with a mean maximal aerobic power of 53 (range 42-65) ml O2.kg-1.min-1 had their lean body mass and vascular fluid volumes measured. Erythrocyte volume was measured by 51Cr, and plasma volume was measured by 125I. The findings concerning the erythrocyte volume, plasma volume, and blood volume of these young men are summarized as follows: 1) these vascular fluid volumes are accurately predicted from several indices of body size; 2) lean body mass is the anthropometric index that is most closely correlated to these vascular fluid volumes; 3) the erythrocyte volumes for a given body surface area are lower, particularly for large individuals, than values previously reported in surveys of undefined populations; 4) aerobic fitness is generally not related to vascular volumes; and 5) F-cell ratio is not related to aerobic fitness.     

After-pulsing,cross-talk,dark-count,and gain of MPPC under 7-T static magnetic field

Multi-pixel photon counters (MPPCs) have been used instead of photomultiplier tubes for positron emission tomography combined with magnetic resonance (PET-MR). However, the effects of the magnetic field (MF) on the intrinsic properties—gain, cross-talk, after-pulsing, and dark-count—have not been sufficiently investigated. Therefore, we measured these properties for two types of MPPCs—S10931-50P and S12572-50P—in a static 7-T MF. These properties were measured with a pulse-shape analysis using pulse data acquired by a digital oscilloscope in the presence of the MF (w/MF) and the absence of the MF (w/o MF) by changing the supplied over-voltages (from 0.95 to 2.1 V for S10931 and from 2.1 to 3.3 V for S12572). No significant differences between the w/MF and w/o MF cases were observed for either MPPC, suggesting that the gain, cross-talk, after-pulsing, and dark-count are insensitive to a 7-T MF. The present work shows that constant MPPC performance is expected under a strong MF and demonstrates positive results for PET-MR.     

Correlations between in vivo 31P MRS measurements, tumor size, cell survival, and hypoxic fraction in the murine EMT6 tumor.

Phosphorus metabolite ratios were measured using 31P magnetic resonance spectroscopy shortly before measurement of cell survival and radiobiologic hypoxic fraction (HF) in EMT6/SF tumors, transplanted into a hindlimb of Balb/c mice. A total of 58 tumors with a volume range of 180 to 1250 mm3 were examined in experiments entailing no anesthesia. Postirradiation tumor cell viability was measured using an in vitro clonogenic assay. Correlations between tumor volume, surviving fraction (SF), HF, phosphorus metabolite ratios, and intracellular pH were computed. Both SF and HF increased significantly with tumor volume as did the metabolite ratios of inorganic phosphorus and phosphomonoesters to nucleoside triphosphates (Pi/NTP and PME/NTP, respectively), as well as Pi to phosphocreatine (Pi/PCr). In comparison to HF, the ratios of Pi/NTP, Pi/PCr, and PME/NTP each yielded significant positive correlations (Kendall correlation coefficients(tau) = 0.25 to 0.33). However, these were not significantly stronger than the correlation between HF and volume (tau = 0.21). Apparent values of tumor pH did not correlate with any other measured parameter. While these results indicate a statistical relationship between HF and the measured metabolite ratios, the widely scattered data, as reflected by magnitude of tau less than 0.35, made metabolite ratios poor predictors of HF in individual tumors.     

Lung cancer: differentiation of tumor, necrosis, and atelectasis by means of T1 and T2 values measured in vitro

In vitro measurements of T1 and T2 values were performed in surgical specimens from 15 patients with lung cancer. Correlation between histologic results and measured values revealed that different pathologic tissues can be characterized by means of T1 and T2 values. The transverse magnetization decay curve of the lung tissue was multiexponential, which can be explained by two different relaxation times, fast T2 and slow T2. The signal intensity of pathologic lung tissues at different pulse sequences was simulated on a signal intensity gradient graph based on measured values of T1, fast T2, slow T2, and water content. The results showed that T2-weighted sequences were more valuable in discriminating viable lung cancer from necrotic tumor and collapsed lung lesions.     

Comparative functional analysis of the Bristow, Magnuson-Stack, and Putti-Platt procedures for recurrent dislocation of the shoulder

Literature on anterior shoulder instability deals most often with elimination of recurrence following reconstruction. We analyzed the subjective function, loss of motion and shoulder strength of three operative procedures: Magnuson-Stack, Bristow, and Putti-Platt. A retrospective review of 27 patients, 9 in each surgical group, with no postoperative dislocations or on-going pain was performed. All patients were male, right hand dominant with the right shoulder affected. Average time of followup was 6.75 years (range, 4.2 to 10.3 years). All patients completed a questionnaire and had their range of motion measured by a hand-held goniometer and their shoulder strength tested on the Cybex II Dynomometer. Peak torque as a percent of body weight and side-to-side differences were calculated for six arm positions and compared to nine right hand dominant controls of similar age and recreational activity. Sixty percent returned to throwing sport. One Magnuson-Stack and Bristow patient felt full functional return to preinjury level. Three patients in each of these two groups returned to unmodified throwing sport whereas no Putti-Platt patient attained this level. Deficit of external rotation at shoulder neutral measured 4.7 degrees, Magnuson-Stack; 12.2 degrees, Bristow; and 21.8 degrees, Putti-Platt. At 90 degrees shoulder abduction, similar deficits in external rotation measured 6.4 degrees, 11.6 degrees, and 28.8 degrees respectively. These values were statistically significant employing analysis of variance. We compared the operative groups as a whole to the controls and compared the operative groups to each other.(ABSTRACT TRUNCATED AT 250 WORDS)     

微量免疫比浊法测定血清免疫球蛋白、转铁蛋白和载脂蛋白含量

本研究建立了一种微量免疫比浊方法,可同时测定人体血清免疫球蛋白(IgG、IgA、IgM)、转铁蛋白(Tf)和载脂蛋白(Apo-AI,Apo-B).方法原理根据人体蛋白质分子的抗原特性,与抗体试剂发生特异性结合后形成微细颗粒复合物在PEG液中沉淀,经呈90度角的荧光照射后所产生的光散射强度求得相应的蛋白质含量.方法具有用血量微、灵敏度高和简单快速的特点.本文用此方法对我国优秀运动员的正常参考值进行了测定.     

Pulmonary vein diameter, cross-sectional area, and shape: CT analysis

PURPOSE: To retrospectively establish normal values for pulmonary vein diameter, cross-sectional area, and shape depicted at computed tomography (CT). MATERIALS AND METHODS: Institutional review board waived patient consent requirement and approved the study. Thin-section contrast material-enhanced spiral chest CT scans in 104 patients, 68 women and 36 men (age range, 19-86 years; mean, 49 years) referred to exclude pulmonary embolism, were retrospectively reviewed. Short-axis diameter and cross-sectional area of the four major pulmonary veins (right inferior and superior, left inferior and superior) were measured at a workstation by using oblique reconstructions. Each vein was measured at six locations, 5 mm apart, starting at atrial ostium. Each measurement was performed three times by an experienced thoracic radiologist, and the mean value was recorded. Roundness was estimated by comparing the ratio of the calculated cross-sectional area to that measured. Mixed effects model was used to compare men and women relative to the distribution of diameters and surface areas and to compare roundness of the right and left veins. RESULTS: Mean pulmonary vein diameters at the ostia were variable: right superior, 11.4-12.4 mm; left superior, 9.6-10.5 mm; right inferior, 12.3-13.1 mm; and left inferior, 9.0-9.9 mm. Diameter and cross-sectional area of the left superior pulmonary vein were significantly larger in men than in women (P < .005). As expected, the caliber of three of the four veins gradually increased as they approached the left atrium. Caliber of the left inferior pulmonary vein decreased as it entered the left atrium. None of the veins were round; all were ovoid. Left-sided veins and venous ostia were less round than right-sided veins (P < .001). CONCLUSION: Pulmonary vein diameter, cross-sectional area, and shape vary. Particular care must be taken when the left inferior pulmonary vein is evaluated for stenosis, as it normally narrows as it enters the left atrium.     

A randomized controlled trial for the effect of passive stretching on measures of hamstring extensibility, passive stiffness, strength, and stretch tolerance

To measure hamstring extensibility, stiffness, stretch tolerance, and strength following a 4-week passive stretching program. Randomized controlled trial. Twenty-two healthy participants were randomly assigned to either a 4-week stretching program consisting of 4 hamstring and hip stretches performed 5 times per week, or a non-stretching control group. Hamstring extensibility and stiffness were measured before and after training using the instrumented straight leg raise test (iSLR). Stretch tolerance was measured as the pain intensity (visual analog scale; VAS) elicited during the maximal stretch. Hamstring strength was measured using isokinetic dynamometry at 30 and 120° s⁻¹. Hamstring extensibility increased by 20.9% in the intervention group following 4 weeks of training (p < 0.001; d = 0.86). Passive stiffness was reduced by 31% in the intervention group (p < 0.05; d = −0.89). Stretch tolerance VAS scores were not different between groups at either time point, and no changes were observed following training. There were no changes in hamstring concentric strength measured at 30 and 120° s⁻¹. Passive stretching increases hamstring extensibility and decreases passive stiffness, with no change in stretch tolerance defined by pain intensity during the stretch. Compared to previous research, the volume of stretching was higher in this study. The volume of prescribed stretching is important for eliciting the strong clinical effect observed in this study.     

Cigarette smoking, field-dependence and contrast sensitivity

This study examined the separate and combined effects of cigarette smoking and field-dependence on contrast sensitivity. No previous research on these relationships exists; however, all three variables are known to be significantly related to many aspects of human performance. Under carefully controlled conditions, 12 smokers and 16 non-smokers were tested for field-dependence and measured for contrast sensitivity (Nicolet CS 2000 Testing System). No differences in contrast sensitivity of smokers were found when measured immediately after smoking 1 cigarette, as compared with having been deprived of smoking for at least 90 min. Habitual smoking and field-dependence were found to be separately and interactively related to contrast sensitivity. A field-independent non-smoker group performed significantly better than a field-dependent smoker group at all but the lowest spatial frequency. The results have important implications for many types of performance, particularly aircraft and motor vehicle operation, and may be valuable for use in selection and training.     

Physical activity,cardiorespiratory fitness,and metabolic outcomes in monozygotic twin pairs discordant for body mass index

This study aims to investigate (i) how monozygotic (MZ ) twin pairs who are discordant for body mass index (BMI ) differ for objectively and subjectively measured physical activity (PA ) and cardiorespiratory fitness (VO ₂max) and (ii) associations of PA and VO ₂max with adiposity and measures of metabolic health, in individual twins and independent of genetic and shared environmental effects within twin pairs. We examined 27 BMI ‐discordant and 14 BMI ‐concordant MZ twin pairs. Fat and fat‐free mass (ffm) were measured by dual‐energy X‐ray absorptiometry and VO ₂max by spiroergometry. PA was measured objectively by accelerometers using ActiGraph GT 1M for daytime activity and Actiwatch AW 7 for 24 h/d. Self‐reported PA was obtained through the Baecke and IPAQ long‐form questionnaires. Objectively measured moderate‐to‐vigorous PA (MVPA , min/d), steps/d, and VO ₂max/kg were significantly lower, by 30%, 21%, and 14%, respectively, in the heavier compared with the leaner co‐twins of the BMI ‐discordant twin pairs. There were no significant differences in self‐reported PA or VO ₂max/ffm. As expected, PA and VO ₂max/ffm were similar in the BMI ‐concordant co‐twins. Furthermore, the 24‐h recording of activity suggested that the heavier co‐twins had more restless sleep during the night, whereas the leaner co‐twins were more active during the day. Within all twin pairs, higher MVPA and steps per day were associated with lower fat percentage and improved metabolic health measures. Objectively, but not subjectively measured PA is associated with lower fat percentage and better metabolic health, independent of genetic and shared environmental factors.     

Experimental and theoretical excitation functions for Br(p,x) reactions

The excitation functions for protons incident on ^natBr were measured from threshold up to 100 MeV by means of the stacked-foil technique. Where applicable, the measured cross-section values are compared with previously published values. Theoretical cross-sections were also calculated by means of the computer code ALICE (IPPE) for comparison purposes.     

Creation of radiofrequency lesions in a porcine model: correlation with sonography, CT, and histopathology

OBJECTIVE: We studied the correlation between sonographic and CT appearances of radiofrequency thermal lesions created in porcine liver and histopathologic findings to evaluate the accuracy of these techniques in revealing the extent of tissue necrosis. MATERIALS AND METHODS: We used sonographic guidance and a 2.0-cm-diameter, eight-prong retractable radiofrequency electrode to view 12 hepatic lesions that were created in five pigs. Biphasic helical CT was performed 12-48 hr after ablation. The animals were sacrificed immediately after CT, and their livers were histopathologically examined. The maximum lesion size in the long and short axes as measured on CT and sonography was then correlated with the histopathologically determined lesion size. RESULTS: On sonography, lesions changed rapidly within 5 min after the termination of ablation. An early echogenic cloud became peripherally hypoechoic with a variable thin echogenic rim. Early (0-2 min after ablation) sonograms led to an underestimation of true lesion sizes on histopathology (r = 0.3-0.49; p < 0.05). Delayed (2-5 min after ablation) sonograms also led to an underestimation of true lesion size (r = 0.5-0.62; p < 0.05); however, lesions were larger and better demarcated. Biphasic contrast-enhanced helical CT revealed avascular lesions surrounded by hyperemic rims that closely correlated with true pathologic lesions size (r = 0.93-0.95; p < 0. 05). Lesions with hyperemic rims that were measured on CT led to overestimations of true lesion size. CONCLUSION: Sonography led to underestimations of the true size of ablated lesions within the first 5 min after creation; however, delayed images provided better results. The avascular lesion measured on contrast-enhanced helical CT closely correlated with the size of ablated tissue; therefore, contrast-enhanced CT is preferred for serially monitoring the effect of radiofrequency ablation.