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Biomedical subjects

R A Moyer

Publications and source records attributed to R A Moyer.

At least 19 recordsLinked to original sources
PubMed2001

Increased nonlinear coupling between turbulence and low-frequency fluctuations at the L-H transition.

The nonlinear coupling between small scale high-frequency turbulence and larger scale lower-frequency fluctuations increases transiently in transitions to improved confinement in the DIII-D tokamak. This increase starts before the rapid turbulence suppression and E x B shear-flow development in the region that becomes the H-mode transport barrier/shear flow region. After the transition, the coupling returns to L-mode levels. These results are consistent with expectations for spontaneous transitions to improved confinement triggered by a turbulence-driven sheared flow.

Journal Article↗
PubMed2001

Quiescent double barrier regime in the DIII-D tokamak.

A new sustained high-performance regime, combining discrete edge and core transport barriers, has been discovered in the DIII-D tokamak. Edge localized modes (ELMs) are replaced by a steady oscillation that increases edge particle transport, thereby allowing particle control with no ELM-induced pulsed divertor heat load. The core barrier resembles those usually seen with a low (L) mode edge, without the degradation often associated with ELMs. The barriers are separated by a narrow region of high transport associated with a zero crossing in the E x B shearing rate.

Journal Article↗
PubMed1995

Peroneal nerve entrapment in athletes.

Peroneal nerve entrapment is one of the less common causes of exercise-induced leg pain in competitive athletes. This type of lower extremity peripheral nerve dysfunction is usually associated with activities that subject the nerve to constant compression or repetitive trauma. Herein, we present our experience with 12 competitive athletes treated for peroneal nerve entrapment. Diagnostic electromyography results, intraoperative findings, and the results of cadaveric dissections are discussed.

Athletic Injuries↗
PubMed1995

Arthroscopic treatment of an avulsion fracture of the intercondylar eminence of the tibia. Case report.

Multiple methods exist for reduction and fixation of an intercondylar eminence fracture of the tibia. Modes of treatment are based on the amount of displacement of the fracture. This article describes an arthroscopic technique as an alternative treatment method in a younger patient population. The arthroscopic reduction of the tibial eminence and cast fixations provides no trauma to the physeal plate, and no further operative procedures for hardware removal are required. Associated injuries may be diagnosed and treated at the time of arthroscopy without the need for arthrotomy.

Arthroscopy↗
PubMed1994

Analgesic effect of intraarticular morphine, bupivacaine, and morphine/bupivacaine after arthroscopic knee surgery.

In a double-blind randomized fashion, 38 patients were divided into four groups according to the intraarticular injection received after arthroscopic surgery. Patients in group I (n = 7) received saline, group II (n = 10) morphine, group III bupivacaine, and group IV (n = 11) morphine and bupivacaine. Before surgery and at 0.5, 1, 1.5, 2, 6, and 24 h postoperatively, pain levels were recorded. In addition, postoperative supplemental i.v. morphine requested by the patient was tabulated. Results showed that the mean consumption of supplemental analgesia was lowest in the morphine/bupivacaine group. Although there was a statistically significant difference in pain scores between the saline group and the other three groups during the early postoperative period, there was no significant difference in pain scores between the morphine, bupivacaine, and morphine/bupivacaine groups. We conclude that postoperative, intraarticular injection of analgesics is beneficial in reducing pain levels. The combination of morphine/bupivacaine appears to be the most beneficial analgesic due to its low supplemental analgesic requirements postoperatively.

Adult↗
PubMed1993

Injuries of the posterior cruciate ligament.

A review of the anatomy and biomechanics of the posterior cruciate ligament, and the systematic approach for the diagnosis and treatment of isolated posterior cruciate ligament injuries and posterior cruciate ligament insufficiency in combination with other ligamentous instabilities is discussed.

Basketball↗
PubMed1990

Arthroscopically-assisted anterior cruciate ligament reconstruction: a follow-up study.

In order to determine the early results of arthroscopically-assisted reconstruction of the anterior cruciate ligament (ACL), a comprehensive follow-up evaluation of 20 athletes with an average postoperative time of 26 months was performed. Clinical knee examination and measurements of thigh circumference, range of motion, and maximum quadriceps/hamstring strength were obtained. A detailed personal interview regarding activity level, subjective ratings, and functional status was conducted. At follow-up, anterior knee laxity was dramatically reduced, with no patients demonstrating a pivot-shift. Thigh circumference, range of motion, and maximum muscle strength were not significantly different than in the normal, uninvolved leg. Sixteen patients (80%) had returned to their preinjury activity level. Only one of the remaining four cited knee problems as part of the reason for not returning to preinjury athletic activities. Patients' subjective ratings were highly favorable. The findings in this study led to the conclusion that modifying traditional open methods of ACL reconstruction to an arthroscopically-assisted technique is an attractive surgical option.

Adolescent↗
PubMed1990

Pyogenic sacroiliitis in a rural population.

We describe 10 cases of pyogenic sacroiliitis occurring in a rural population. Seven were male and 3 were female with a mean age of 22.4 years. None was a recent intravenous drug abuser. Five patients had a history of recent pelvic trauma. 99mTechnetium scintiscans revealed increased sacroiliac (SI) joint uptake in 8 of 8 cases. Blood cultures were positive in 60% of patients. Staphylococcus aureus was isolated in 7 cases from blood and/or SI aspirates and Hemophilus influenzae type B in one case. Nine of 10 patients recovered completely. One underwent arthrodesis for recurrent SI pain without evidence of relapse of infection. Median followup was 18 months.

Adolescent↗
PubMed1990

Testing for isometry during reconstruction of the anterior cruciate ligament. Anatomical and biomechanical considerations.

Instrumented tibiofemoral (bone-to-bone) excursion wires were implanted in the mid-substance of the anteromedial, central, and posterior fiber-regions of the anterior cruciate ligament through limited anterior and posterior arthrotomies in eight fresh knees from cadavera. The change in the distance of linear separation between each pair of osseous fiber-insertion sites was measured and was plotted against the angle of flexion of the knee as the knee was cycled through a 120-degree range of motion. Testing conditions likely to be present during intraoperative testing for isometry were used (anterior cruciate fibers transected, quadriceps relaxed, femur stabilized with the patient in the supine position and the leg freely dependent, and motion of the knee induced in neutral rotation by force applied at the level of the foot). In no instance did the insertion-site centers of any fiber-region exhibit isometric behavior (change in the distance of linear separation of 1.0 millimeter or less). The least deviations from isometry (range, 1.4 to 3.1 millimeters) were observed for the anteromedial sites, under conditions when the gravitational dependency of the lower leg was constrained. When the leg hung in a dependent manner during passive motion, the deviation from isometry of the anteromedial sites of insertion increased significantly (range, 2.8 to 5.6 millimeters). The central sites of insertion were generally less isometric than the anteromedial sites, and the posterior sites were the least isometric, regardless of testing conditions.

Aged↗
PubMed1990

Prototheca wickerhamii tenosynovitis.

Prototheca wickerhamii is an algae-like organism rarely implicated in skin or soft tissue infections. We describe the first case (to our knowledge) of Prototheca tenosynovitis which followed median nerve release for carpal tunnel syndrome. Clinical presentation, operative findings, histopathology, microbiology and treatment of this unusual infection are discussed.

Amphotericin B↗
PubMed1989

Acute calcific tendinitis of the hand and wrist: a report of 12 cases and a review of the literature.

Acute calcific tendinitis is a frequently unrecognized cause of hand and wrist tenderness and swelling. We report 12 cases seen over an 8-year period. Roentgenograms showed deposits in various peritendinous sites especially near the pisiform. Special views may be required for visualization. A correct diagnosis was made in 5/12 cases; other etiologies considered included closed-space infections. In most cases, treatment consisted of immobilization plus nonsteroidal antiinflammatory drugs or local steroid injections. Results were uniformly good. Seven of 7 patients demonstrated resolution of calcium deposits on subsequent roentgenograms. Failure to recognize this entity may cause unnecessary investigation and therapy.

Adult↗
PubMed1987

Osteochondritis dissecans: analysis of mechanical stability with radiography, scintigraphy, and MR imaging.

Twenty-one joints with stable (n = 9) or loose (n = 12) osteochondritis dissecans (OCD) lesions were examined in 15 subjects with plain radiography, three-phase bone scintigraphy, and magnetic resonance (MR) imaging. The lesion size and the thickness of the sclerotic margin as measured on plain radiographs were good parameters for predicting loosening. However, bone scintigraphy was more sensitive and specific in determining the mechanical stability of OCD lesions. MR imaging permitted direct visualization of loosening and fragment displacement; the latter permits differentiation of in situ loosening from a grossly unstable lesion. The noninvasive nature of bone scintigraphy and MR imaging makes them potentially preferable diagnostic modalities to arthrography for evaluating the mechanical status of OCD lesions.

Adolescent↗
PubMed1984

Giant synovial cysts.

Giant synovial cysts (GSC) are large, well-defined cavities, containing synovial fluid and lined by a synovium-like membrane, which extend for a variable distance outside the joint cavity. We are reporting 15 cases of GSC of various joints. Rheumatoid arthritis is the most common disease process reported in association with GSC. We suggest that trauma may be a more important cause of GSC than has previously been described. Arthrography and ultrasonography are both helpful in diagnosing these large cysts, especially in the knee to aid in differentiating GSC from thrombophlebitis.

Adolescent↗
PubMed1975

Converging collimation and a large-field-of-view scintillation camera.

Three low-energy multihole converging collimators were evaluated in reference to accepted imaging parameters using a prototype large-field-of-view scintillation camera. A substantial improvement in resolution and/or sensitivity with depth was observed. Because of the large detector, the inherent reduction in field size due to convergence was not detrimental to satisfactory imaging of most target volumes. Such collimation should prove to be of significant clinical value.

Radionuclide Imaging↗