The effect of obesity on inflammatory cytokine and leptin production following acute mental stress.

Obesity may contribute to cardiovascular disease (CVD) risk by eliciting chronic systemic inflammation and impairing the immune response to additional stressors. There has been little assessment of the effect of obesity on psychological stress, an independent risk factor for CVD. Therefore, it was of interest to examine interleukin-6, tumor necrosis factor-α, interleukin-1ß (IL-1ß), interleukin-1 receptor antagonist (IL-1Ra), and leptin following an acute mental stress task in nonobese and obese males. Twenty college-aged males (21.3 ± 0.56 years) volunteered to participate in a 20-min Stroop color-word and mirror-tracing task. Subjects were recruited for obese (body mass index: BMI > 30) and nonobese (BMI < 25) groups, and blood samples were collected for enzyme-linked immunosorbent assay analysis. The acute mental stress task elicited an increase in heart rate, catecholamines, and IL-1ß in all subjects. Additionally, acute mental stress increased cortisol concentrations in the nonobese group. There was a significant reduction in leptin in obese subjects 30 min posttask compared with a decrease in nonobese subjects 120 min posttask. Interestingly, the relationship between the percent change in leptin and IL-1Ra at 120 min posttask in response to an acute mental stress task was only observed in nonobese individuals. This is the first study to suggest that adiposity in males may impact leptin and inflammatory signaling mechanisms following acute mental stress.

Stiffness, viscosity, and upper-limb inertia about the glenohumeral abduction axis.

To evaluate the dynamic properties of the shoulder and understand how they are controlled by the central nervous system, glenohumeral-joint stiffness and viscosity and upper-limb inertia were quantified under various levels of muscle contraction in seven healthy human subjects. Through a cast attachment, the upper limb was perturbed in a precise pattern by a computer-controlled servomotor to manifest the dynamic properties of the joint. The recorded joint position and torque were used to estimate joint stiffness and viscosity and upper-limb inertia. With moderate muscle contraction, the stiffness and viscosity increased several fold. A stiffer shoulder joint associated with stronger muscle contraction made the shoulder more stable and protected it from potential injuries during strenuous tasks. Joint viscosity, especially the stronger viscous damping associated with more strenuous contraction, smoothed shoulder movement and stabilized the joint. From the control viewpoint, the glenohumeral joint responded to the central nervous system more quickly with increasing muscle contraction, which was useful during strenuous tasks. On the other hand, the central nervous system controlled stiffness and viscosity synchronously so that it dealt with only a nearly constant damping ratio of the joint over various levels of contraction, which simplified its task substantially. This approach quantified the dynamic and static properties of the shoulder under various levels of contraction more accurately and completely than a manual test, and it can potentially be used to evaluate changes in these properties caused by musculoskeletal injuries and their surgical treatments.

Long-term results of total hip arthroplasty in congenital dislocation and dysplasia of the hip. A follow-up note.

Twenty-three of twenty-nine hips that were previously reported on were studied at an average of fourteen years (range, eight to 16.5 years) after total hip arthroplasty with cement. The original arthroplasties had been performed between November 1971 and January 1976. In all hips, there was dislocation or severe dysplasia. In six hips, superolateral bone grafts were used to increase acetabular coverage. At the latest follow-up examination, seven hips were rated excellent; nine, good; and one, fair. There were six failures (26 per cent) that were revised: four hips (17 per cent) had a fractured Trapezoidal-28 stem, one had loose femoral and acetabular components, and one had loosening of only the acetabular component. Radiographic analysis of the remaining hips revealed that one had progressive acetabular radiolucencies. This patient had an excellent clinical result. Two-thirds of the failures were due to a fractured stem.

Macrocerebellum: neuroimaging and clinical features of a newly recognized condition.

Other than hamartomatous enlargement of the cerebellum as in Lhermitte-Duclos syndrome, diffuse enlargement of the cerebellum is not clearly described. We report four patients (ages 9 months to 2 years) with diffusely enlarged cerebelli as identified by measurement of the cerebellum and comparison to age appropriate normal values. The cerebellar measurements were determined in absolute numbers and expressed as ratios of cerebellum to whole brain and supratentorial brain. The clinical features of these four children (3 boys, 1 girl) consistently include global developmental delay, tone abnormalities, preserved reflexes, delayed or abnormal maturation of the visual system (oculomotor apraxia), and deficient or delayed myelination of cerebral white matter. The etiology of the macrocerebellum is unknown but we propose that the cerebellum is responding to the elaboration of growth factors intended to augment the slow development of cerebral structures. Regardless of the etiology, the finding of a macrocerebellum appears to allow the clinician to predict the clinical features of the patient and probably represents a marker for disturbed cerebral development.

Ligamentous control of shoulder stability based on selective cutting and static translation experiments.

The glenohumeral joint is a complex articulation with little inherent stability, capable of significant rotations. The capsuloligamentous structures play a critical static role in maintaining joint stability. Various components have been identified both anatomically and functionally, with their contributions varying depending on joint position and the direction of applied forces.

Neurovascular problems in the forearm, wrist, and hand.

This article attempted to summarize the most common neurovascular injuries of the upper extremity, particularly the forearm, wrist, and hand. Although these injuries are rarely encountered in athletes, their pathology and treatment must be understood by the treating physician. Failure to recognize these injuries in a timely manner can lead to delay in diagnosis and weeks or months of lost participation by the athlete. The sports medicine physician must be aware of the potential risk for injury to the neurovascular structures, particularly in the athlete exposed to repetitive use or impact of the upper extremity. Timely recognition, diagnosis, and treatment will avoid the potential risk for permanent injury.

Recovery of intravenously infused chromium EDTA and lithium sulphate in the urine of cattle and their use as markers to measure urine volume.

A series of metabolism experiments investigated the recovery of continuous-, intravenously infused chromium complexed with ethylenediamine tetra-acetic acid (CrEDTA) and lithium sulphate in the urine of cattle with a view to using the markers to estimate urine and metabolite output in grazing cattle. The recovery of Cr in urine from these infusions was similar (90%) in metabolism trials when cattle consumed three very contrasting diets: high-grain formulated pellet, lucerne hay (Medicago sativa) or low-quality native grass hay (predominantly Heteropogon contortus). By contrast, Li recovery in urine averaged 46.3 ± 0.40% and 72.6 ± 0.43% for native pasture and lucerne hays, respectively, but was not constant across days. There was negligible transfer of Cr from CrEDTA in blood serum to the rumen or faeces, whereas appreciable quantities of infused Li were found in both. The ratio of urine volume estimated by spot samples and marker dilution of Cr, to urine volume measured gravimetrically, was 1.05. In grazing studies using rumen-fistulated (RF) steers grazing seven different tropical and temperate grass and legume pastures, the ratio of concentrations of purine derivatives (PD) to Cr in spot samples of urine was shown to vary diurnally in the range of 49% to 157% of the average 24 h value. This finding indicated the need for regular sampling of urine to achieve an accurate average value for the PD : Cr ratio in urine for use in estimating urinary PD excretion and hence microbial protein production in the rumen. It was concluded that continuous, intravenous infusion of CrEDTA resulted in a constant recovery of Cr in the urine of cattle across diets and, provided an intensive sampling regime was followed to account for diurnal variation, it would be suitable as a marker to estimate urine volume and urinary output of PD in grazing cattle.

Spur reformation after arthroscopic acromioplasty.

Rotator cuff pathology has been associated with a hooked acromial morphology. Impingement syndrome has traditionally been considered to be the result of bony encroachment into the subacromial space. This report of a spur recurrence after acromioplasty presents evidence that acromial morphology may be a reactive change attributable to primary rotator cuff insufficiency.

Effect of joint compression on inferior stability of the glenohumeral joint.

UNLABELLED: To determine the relative importance of negative intraarticular pressure, capsular tension, and joint compression on inferior stability of the glenohumeral joint we studied 17 fresh, normal adult cadaver shoulders using a "3 degrees of freedom" shoulder test apparatus. Translations were measured in intact and vented shoulders while a 50-N superior and inferior directed force was applied to the shoulder. Three different joint compressive loads (22 N, 111 N, 222 N) were applied externally. Tests were performed in 3 positions of humeral abduction in the scapular plane (0 degree, 45 degrees, 90 degrees) and in 3 positions of rotation (neutral, maximal internal, and maximal external). After tests of the intact and vented shoulder, the glenohumeral ligaments were sectioned and tests were repeated. With minimal joint compression of 22 N, negative intraarticular pressure and capsular tension limited translation of the humeral head on the glenoid. Increasing the joint compressive load to 111 N resulted in a reduction of mean inferior translation from 11.0 mm to 2.0 mm at 0 degree abduction, from 21.5 mm to 1.4 mm at 45 degrees abduction, and from 4.5 mm to 1.2 mm at 90 degrees abduction. With a compressive load of 111 N, venting the capsule or sectioning of glenohumeral ligaments had no effect on inferior stability. CLINICAL RELEVANCE: Glenohumeral joint compression through muscle contraction provides stability against inferior translation of the humeral head, and this effect is more important than negative intraarticular pressure or ligament tension.

Cemented total knee arthroplasty for gonarthrosis in patients 55 years old or younger.

The results of 68 cemented total knee arthroplasties (TKAs) in 50 patients with gonarthrosis who were 55 years old or younger at the time of surgery were reviewed. These patients were operated on between 1979 and 1987 and were followed for an average of 6.2 years. The average age of the patients was 50 years. Patients were evaluated by the Hospital for Special Surgery knee score. The average preoperative score was 53, and the average follow-up score was 90. Overall, 55 TKAs were rated as excellent and 13 as good. Using the knee rating score advocated by the Knee Society, the average postoperative score was 92 for pain and 84 for function. There were four successful reoperations for patellar component loosening, all in metal-backed patellae. The femoral and tibial components in these patients were intact, and at the follow-up period, two knees were rated as excellent and two as good. Detailed roentgenographic evaluation demonstrated that 20% of tibial components had radiolucencies in at least one zone on the anteroposterior roentgenogram and in 11% on the lateral roentgenogram. Femoral radiolucencies occurred in only 2% of knees. Patellar radiolucencies in one or more zones occurred in 20% of knees that had not had patellar revision. No complete or progressive radiolucencies at the bone-cement interface were noted for any component, and no components were considered to be roentgenographically loose. Cemented TKAs can achieve excellent long-term results in patients younger than 55 years old with gonarthrosis of the knee. These results compare with those obtained in published reports on older age groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraarticular fibrous nodule as a cause of loss of extension following anterior cruciate ligament reconstruction.

Loss of motion is a well-known complication following anterior cruciate ligament (ACL) reconstruction. We have found that loss of extension is more disabling than loss of flexion, and is a more common problem following arthroscopic assisted ACL reconstruction. We are reporting on a group of 21 patients who have developed restricted knee extension following ACL reconstruction utilizing either the central one-third of the patellar ligament or the hamstring tendons as an autogenous graft. The patients presented at an average of 4 months postoperatively with a clinical syndrome of loss of extension associated with pain at terminal extension, crepitus, and grinding with attempted extension beyond their limit. The consistent finding at arthroscopy was a fibrous nodule occupying the intercondylar notch, varying in size from 1 x 1 to 2 x 3 cm, and presenting a mechanical block to full extension. It appears that anterior placement of the graft, particularly on the tibia, results in injury to the graft and subsequent nodule formation. Removal of the nodule resulted in improvement of an average preoperative loss of extension of 11 degrees, to 3 degrees at surgery, and 0 degrees at 1 year follow-up. The average side-to-side difference in terminal extension at final examination, using the uninvolved limb for comparison, was 3 degrees. Histology was available for review on 19 of the 21 patients operated on. The consistent microscopic finding within the nodule was the presence of disorganized dense fibroconnective tissue that, with time, underwent modulation to fibrocartilage. It is postulated that this occurs in response to compressive loading of the nodule.

Articular contact patterns of the normal glenohumeral joint.

The purpose of this study was to determine the articular contact patterns of the normal glenohumeral joint, and to correlate these findings with cartilage and subchondral bone architecture. We studied 10 normal shoulders of cadavers. We removed all soft tissues except the joint capsule and rotator cuff and then placed the shoulders on a testing apparatus that allowed freedom of translation in three planes. After the humerus was placed in a neutral position of rotation, articular contact patterns were measured with specially prepared prescale Fuji film so that it could be inserted between the joint surfaces. Articular contact was analyzed with 222 and 444 N of joint compressive load, and the humerus was positioned in scapular plane abduction of 0 degree, 45 degrees, and 90 degrees. The contact patterns were then digitized to determine percentage contact of the humeral head on the glenoid. We studied 12 additional cadaver shoulders with fine microradiographs and histologic techniques after we sectioned the glenoids in the anterior-posterior and superior-inferior planes. We then analyzed articular and subchondral architecture. We found that when the shoulder was adducted the contact area of the humeral head on the glenoid was limited to the anatomic region of the central glenoid known as the "bare area." This was histologically and radiographically an area of cartilage thinning and increased subchondral bone density. As the shoulder was abducted the articular congruity and percentage contact area increased. We concluded that there was a slight articular mismatch with the shoulder adducted in the normal shoulder. Histologic and radiographic studies suggested that the central bare area region of the glenoid was a region of increased compressive loading. As the shoulder was abducted the joint became more congruent and thus the contact area of the humeral head on the glenoid increased.