University of Tennessee Health Science Center

About: University of Tennessee Health Science Center is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 15716 authors who have published 26884 publications receiving 1176697 citations.

Preliminary criteria for clinical remission in rheumatoid arthritis

Abstract: A study was conducted to develop criteria for clinical remission in rheumatoid arthritis (RA). Data were provided by 35 rheumatologists on 175 RA patients considered to be in complete remission (with or without antirheumatic therapy) and 169 RA patients in partial remission or with active disease. Six criteria yielded optimal discrimination: morning stiffness absent or not exceeding 15 minutes, no fatigue, no joint pain by history, no joint tenderness, no joint or tendon sheath swelling, and no elevation of erythrocyte sedimentation rate. In this study sample, the presence of five or more of these criteria in an individual patient yielded 72% sensitivity for clinical remission and 100% specificity in discriminating RA patients with active disease. In a population sample, it is estimated that the overall accuracy of these criteria would be more than 90% in RA patients.

Laparoscopic repair of ventral hernias: nine years' experience with 850 consecutive hernias.

Abstract: One result of the 2 million laparotomies performed in the United States each year is an incisional hernia rate of 3% to 20%,1 necessitating repair of approximately 90,000 ventral hernias annually. Factors associated with formation of an incisional hernia include wound infection, immunosuppression, morbid obesity, previous operations, prostatism, and surgery for aneurysmal disease. Abdominal wall defects are typically observed within the first 5 years after the surgical incision is made, but they may develop long afterward.2 These hernias contribute importantly to the long-term morbidity of conventional surgery. Until techniques for the prevention of hernias are established, repair of these defects will remain an important problem for all abdominal surgeons. Many hernia repair methods have been described. Traditional primary repair entails a laparotomy with suture approximation of strong fascial tissue on each side of the defect. However, recurrence rates after this procedure range from 41% to 52% during long-term follow-up.2-4 Herniorrhaphies in which large prosthetic meshes are implanted appear to have lower failure rates (12-24%), but the required dissection of wide areas of soft tissue contributes to an increased incidence of wound infections and wound-related complications (12% or higher).3,5,6 These problems have stimulated a continuing search for new techniques for repairing ventral hernias. The interest in less morbid herniorrhaphies and the appeal of minimally invasive surgery encouraged development of laparoscopic methods for repairing incisional hernias. These techniques are based on the same physical and surgical principles as the open underlay procedure described by Stoppa,3 Rives et al,7 and Wantz.8 Since the first report of laparoscopic ventral hernia repair (LVHR) in 1992,9 the operation has grown in popularity with the belief that it may offer shorter hospital stays, improved patient outcomes, and fewer complications than traditional open procedures. Several comparative studies are now available that support this assertion.10-14 Limiting factors in most of these and the noncomparative series that describe LVHR include limited sample size, varying techniques, and restricted follow-up.15-18 We here describe a study of outcomes achieved with LVHR performed by 4 attending surgeons using the same surgical technique and standardized perioperative regimens and follow-up protocols. The reported series includes every patient in whom the operation was performed or attempted. Data on most patients were collected prospectively, and the follow-up time extends to more than 8 years. The goal of the study was to assess the safety and efficacy of LVHR.

The origins of two-state spontaneous membrane potential fluctuations of neostriatal spiny neurons

Abstract: In vivo intracellular recordings of spontaneous activity of neostriatal spiny cells revealed two-state behavior, i.e., characteristic shifts of membrane potential between two preferred levels. The more polarized level, called the Down state, varied among neurons from -61 to -94 mV. The more depolarized level, called the Up state, varied among neurons form -71 to -40 mV. For any one neuron, the membrane potential in the Up and Down states was constant over the period of observation (from 15 min to 4 hr), and the cells spent little time in transition between states. The level of membrane potential noise was higher in the Up state than in the Down state. Spontaneous membrane potential fluctuations were not abolished by experimental alteration of the membrane potential, but the time spent in each state was altered when intracellular current was used to vary the baseline membrane potential. Neither the sodium nor the calcium action potential that could be evoked by depolarization of spiny neurons was required for the occurrence of spontaneous shifts of membrane potential. Blockade of these action potentials using intracellular injection of QX314 and D890, respectively, altered neither the incidence of the membrane potential shifts nor the preferred membrane potential in either state. In contrast, antagonism of voltage-dependent potassium channels with intracellular cesium altered membrane potential shifts. In the presence of QX314 and D890, intracellular injection of cesium caused little or no change in the Down state and a large depolarizing shift in the Up state (to about -20 mV). Under these circumstances, the neuron responded to current in a nearly linear manner, and membrane conductance was found to be increased in the Up state, attributable to a membrane conductance with the same reversal potential as that of the synaptic potential evoked by cortical stimulation. These results indicate that the event underlying the Up state is a maintained barrage of synaptic excitation, but that the membrane potential achieved during the Up state in neostriatal spiny neurons is determined by dendritic potassium channels that clamp the membrane potential at a level determined by their voltage sensitivity. Neostriatal spiny neurons ordinarily receive enormously powerful excitation, which would drive the cells to saturation, and probably destroy them, if it were not for these potassium currents.

Leg Muscle Mass and Composition in Relation to Lower Extremity Performance in Men and Women Aged 70 to 79: The Health, Aging and Body Composition Study

Abstract: OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP). DESIGN: A cross-sectional study, using baseline data of the Health, Aging and Body Composition study (1997/98). SETTING: Medicare beneficiaries residing in ZIP codes from the metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand seventy-five well-functioning black and white men and women aged 70 to 79. MEASUREMENTS: Two timed tests (6-meter walk and repeated chair stands) were used to measure LEP. Muscle cross-sectional area and muscle tissue attenuation (indicative of fat infiltration) were obtained from computed tomography scans at the midthigh. Body fat was assessed using dual-energy x-ray absorptiometry. RESULTS: Blacks had greater muscle mass and poorer LEP than whites. Black women had greater fat infiltration into the muscle than white women. After adjustment for clinic site, age, height, and total body fat, smaller muscle area was associated with poorer LEP in all four race-gender groups. (Regression coefficients, expressed per standard deviation (±55 cm2) of muscle area, were 0.658 and 0.519 in white and black men and 0.547 and 0.435 in white and black women, respectively, P .7) or between race and muscle attenuation (P> .2) were observed. CONCLUSION: Smaller midthigh muscle area and greater fat infiltration in the muscle are associated with poorer LEP in well-functioning older men and women.