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Biomedical subjects

R J Fox

Publications and source records attributed to R J Fox.

At least 19 recordsLinked to original sources
PubMed2003

MRI findings in Susac's syndrome.

BACKGROUND: Susac syndrome (SS) is a self-limited syndrome, presumably autoimmune, consisting of a clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. All three elements of the triad may not be present or recognized, and MR imaging is often necessary to establish the diagnosis. OBJECTIVE: To determine the spectrum of abnormalities on MRI in SS. METHODS: The authors reviewed the MR images of 27 previously unreported patients with the clinical SS triad, and 51 patients from published articles in which the MR images were depicted or reported. RESULTS: All 27 patients had multifocal supratentorial white matter lesions including the corpus callosum. The deep gray nuclei (basal ganglia and thalamus) were involved in 19 (70%). Nineteen (70%) also had parenchymal enhancement and 9 (33%) had leptomeningeal enhancement. Of the 51 cases from the literature, at least 32 had callosal lesions. The authors could not determine the presence of callosal lesions in 18 of these patients, and only one was reported to have a normal MRI at the onset of encephalopathy. CONCLUSIONS: The MR scans in SS show a rather distinctive pattern of supratentorial white matter lesions that always involve the corpus callosum. There is often deep gray matter, posterior fossa involvement, and frequent parenchymal with occasional leptomeningeal enhancement. The central callosal lesions differ from those in demyelinating disease, and should support the diagnosis of SS in patients with at least two of the three features of the clinical triad.

Adult↗
PubMed2002

High-dose methylprednisolone for acute closed spinal cord injury--only a treatment option.

BACKGROUND: A systematic review of the evidence pertaining to methylprednisolone infusion following acute spinal cord injury was conducted in order to address the persistent confusion about the utility of this treatment. METHODS: A committee of neurosurgical and orthopedic spine specialists, emergency physicians and physiatrists engaged in active clinical practice conducted an electronic database search for articles about acute spinal cord injuries and steroids, from January 1, 1966 to April 2001, that was supplemented by a manual search of reference lists, requests for unpublished additional information, translations of foreign language references and study protocols from the author of a Cochrane systematic review and Pharmacia Inc. The evidence was graded and recommendations were developed by consensus. RESULTS: One hundred and fifty-seven citations that specifically addressed spinal cord injuries and methylprednisolone were retrieved and 64 reviewed. Recommendations were based on one Cochrane systematic review, six Level I clinical studies and seven Level II clinical studies that addressed changes in neurological function and complications following methylprednisolone therapy. CONCLUSIONS: There is insufficient evidence to support the use of high-dose methylprednisolone within eight hours following an acute closed spinal cord injury as a treatment standard or as a guideline for treatment. Methylprednisolone, prescribed as a bolus intravenous infusion of 30 mg per kilogram of body weight over fifteen minutes within eight hours of closed spinal cord injury, followed 45 minutes later by an infusion of 5.4 mg per kilogram of body weight per hour for 23 hours, is only a treatment option for which there is weak clinical evidence (Level I- to II-1). There is insufficient evidence to support extending methylprednisolone infusion beyond 23 hours if chosen as a treatment option.

Acute Disease↗
PubMed2001

Acute, chronic, and recurrent varicella zoster virus neuropathy without zoster rash.

The authors report three patients with acute, chronic, and recurrent neuropathy associated with varicella zoster virus (VZV) infection but without zoster rash. CSF of all three patients contained VZV immunoglobulin G antibody, but not herpes simplex virus. In two patients, serum/CSF ratios of VZV immunoglobulin G were reduced compared to normal ratios for immunoglobulin G and albumin, and one patient also had VZV immunoglobulin M in CSF. All three patients received antiviral therapy and improved. The diagnosis of nervous system infection by VZV may be confirmed by the presence of antibody to VZV in CSF even without detectable VZV DNA.

Acute Disease↗
PubMed2001

Aphemia: an isolated disorder of articulation.

Aphemia is a disorder with prominent speech abnormality. Since its description by Broca, there has been debate regarding the neuropsychological disorganization underlying aphemia: is aphemia an articulatory disorder or a language disorder? We describe a patient with markedly impaired articulation, but preserved receptive and written language function and buccal-facial coordination. The location of his stroke was in the left precentral gyrus, undercutting a small area of motor and premotor cortex. This case suggests that aphemia can occur as an isolated articulation deficit without language involvement or more widespread bulbar apraxia, and may be a severe form of apraxia of speech.

Aphasia, Broca↗
PubMed2001

Multiple sclerosis: the importance of early recognition and treatment.

Primary practitioners need to know how to expedite the diagnosis and treatment of multiple sclerosis (MS), because treatments that can slow its course appear to be most effective when started early. Several lines of evidence demonstrate that tissue damage occurs very early in the disease, and much of this damage is clinically silent.

Adjuvants, Immunologic↗
PubMed2000

Treatment of Bickerstaff's brainstem encephalitis with immune globulin.

Bickerstaff's brainstem encephalitis (BBE) is an immune disorder of unknown etiology. Previous reports of successful treatment of BBE involved steroids or plasma exchange. We describe a patient with BBE who demonstrated rapid clinical recovery after treatment with intravenous immune globulin. Our findings suggest that IVIg is an alternative treatment in BBE, especially when plasma exchange is difficult or contraindicated. Our patient also demonstrated pseudoretraction and pseudoptosis during clinical recovery, an observation which supports a differential immune attack on components of the third nerve or supranuclear regions, and expands our understanding of the pathophysiology of BBE.

Adult↗
PubMed2000

The Compass Elbow Hinge: indications and initial results.

The Compass Elbow Hinge uses Illizarov's methods of fixation to externally hold the elbow reduced and allow both passive and active motion. Eleven patients with degenerative disease, contracture or instability were treated with the Compass Elbow Hinge and were retrospectively evaluated at an average follow-up of 29 months (range: 18-62 months). One was lost to follow-up. Patients with degenerative changes underwent fascia lata interposition while those treated for contractures underwent anterior and posterior capsular release with or without fascia lata interposition. Those with elbow instability underwent ligament reconstruction. The device was removed after 6 weeks and seven of the 11 patients were satisfied with the outcome of the operation. Stability could not be achieved in two patients with coronoid fractures that were not reconstructed. One patient did not tolerate the device and requested its removal with subsequent subluxation. We conclude that patient selection and compliance are key elements in achieving a satisfactory outcome with the device.

Adult↗
PubMed2000

Trapeziometacarpal arthroplasty using the entire flexor carpi radialis tendon.

Fifty-eight patients (62 joints) with arthritis of the thumb carpometacarpal joint were treated with resection arthroplasty, ligament reconstruction, and tendon interposition with the entire flexor carpi radialis tendon. The mean age of the patients at the time of surgery was 58.4 years (range, 28-80 years), and the average followup was 42.5 months (range, 21-86 months). The entire flexor carpi radialis tendon was used for reconstruction and interposition. In 32 of the 62 joints, a partial trapezoidectomy was performed for scaphotrapezoidal arthritis. Finger-tip pinch improved by 88%, key pinch improved by 86%, and grip strength improved by 69%. Palmar and radial abduction also improved by 8% and 10%, respectively. Fifty-five (95%) patients reported excellent pain relief, whereas three patients reported only mild pain. No patients experienced an increase in pain. All thumbs were stable radiographically. This study indicated ligament reconstruction with tendon interposition, accompanied by partial trapezoidectomy when indicated, provides excellent pain relief and restoration of function. No morbidity was observed with use of the entire flexor carpi radialis tendon.

Adult↗
PubMed2000

New low-contrast vision charts: reliability and test characteristics in patients with multiple sclerosis.

The quantitative assessment of visual function in multiple sclerosis (MS) clinical trials has been limited to Snellen visual acuity. The purpose of this study was to examine the inter-rater reliability and test characteristics of a new visual outcome measure, the Low-Contrast Sloan Letter Charts, in patients with MS and visually-asymptomatic volunteers. Contrast letter acuity scores (letter scores) were measured at each of four contrast levels (100, 5, 1.25 and 0.6%) by two independent raters. Inter-rater agreement was described with the intraclass correlation coefficient (ICC) and comparison of mean scores. Excellent inter-rater agreement (ICC=0.86 - 0.95) was demonstrated at each contrast level among MS patients (n=100) and visually-asymptomatic volunteers (n=33). Average letter scores at the lowest contrast level (0.6%) were highly variable in the MS group, even among patients with visual acuities of 20/20 or better, and among those who required no assistance for ambulation. Low-Contrast Sloan Letter Chart testing is a highly reliable method of visual assessment, and provides information on an aspect of neurologic impairment in MS which is not captured by Snellen visual acuity or ambulation status. This new method demonstrates excellent potential as a visual function outcome measure for future MS clinical trials.

Adolescent↗
PubMed1999

Relative contribution of the ACL, MCL, and bony contact to the anterior stability of the knee.

Ligaments and other soft tissues, as well as bony contact, all contribute to anterior stability of the knee joint. This study was designed to measure the in situ force in the medial collateral ligament (MCL), anterior cruciate ligament (ACL), posterolateral structures (PLS), and posterior cruciate ligament (PCL) in response to 110 N anterior tibial loading. The changes in knee kinematics associated with ACL deficiency and combined MCL+ACL deficiency were also evaluated. Utilizing a robotic/universal force-moment sensor system, ten human cadaveric knee joints were tested between 0 degrees and 90 degrees of knee flexion. This unique testing system is designed to determine the in situ forces in structures of interest without making mechanical contact with the tissue. More importantly, data for individual structures can be obtained from the same knee specimen since the robotic manipulator can reproduce the motion of the intact knee. The in situ forces in the ACL under anterior tibial loading to 110 N were highest at 15 degrees flexion, 103 +/- 14 N (mean +/- SD), decreasing to 59.2 +/- 30 N at 90 degrees flexion. For the MCL, these forces were 8.0 +/- 3.5 N and 38.1 +/- 25 N, respectively. Forces due to bony contact were as high as 34.1 +/- 23 N at 30 degrees flexion, while those in the PLS were relatively small at all flexion angles. Combined MCL+ACL deficiency was found to significantly increase anterior tibial translation relative to the ACL-deficient knee only above 60 degrees of knee flexion. These findings confirm the hypothesis that there is significant load sharing between various ligaments and bony contact during anterior tibial loading of the knee. For this reason, the MCL and osteochondral surfaces may also be at significant risk during ACL injury.

Aged↗
PubMed1998

The relationship between daily stress and symptoms of irritable bowel: a time-series approach.

Irritable bowel syndrome (IBS), a chronic disorder that includes symptoms such as abdominal pain and altered bowel habits, affects up to 22% of people in Western populations. The causes of IBS are not well understood, but are believed to be multifactorial. Although stress is widely believed to be implicated, empirical evidence in support of this is lacking, perhaps because a typical between-participants analysis ignores individual differences and therefore may obscure any link. The present study used a within-person, lagged time-series approach to investigate the links between everyday stress and symptomatology in 31 IBS sufferers. Both everyday stress and symptomatology exhibited serial dependence for a statistically significant proportion of sufferers. Multiple regression analysis carried out on same-day and lagged relationships up to and including 4 days found that, for over half the participants, everyday stress and symptoms were related. The best regression model was one in which symptoms were a function of hassles and symptoms on the previous 2 days, and hassles on the same day, fitting the data for 67% of participants. This prospective study confirms other studies that have suggested stress is a significant factor in IBS, and concludes that stress management programs may be both useful and cost-effective in the treatment of IBS.

Adult↗
PubMed1997

In situ forces in the anterior cruciate ligament and its bundles in response to anterior tibial loads.

The anterior cruciate ligament has a complex fiber anatomy and is not considered to be a uniform structure. Current anterior cruciate ligament reconstructions succeed in stabilizing the knee, but they neither fully restore normal knee kinematics nor reproduce normal ligament function. To improve the outcome of the reconstruction, it may be necessary to reproduce the complex function of the intact anterior cruciate ligament in the replacement graft. We examined the in situ forces in nine human anterior cruciate ligaments as well as the force distribution between the anteromedial and posterolateral bundles of the ligament in response to applied anterior tibial loads ranging from 22 to 110 N at knee flexion angles of 0-90 degrees. The analysis was performed using a robotic manipulator in conjunction with a universal force-moment sensor. The in situ forces were determined with no device attached to the ligament, while the knee was permitted to move freely in response to the applied loads. We found that the in situ forces in the anterior cruciate ligament ranged from 12.8 +/- 7.3 N under 22 N of anterior tibial load applied at 90 degrees of knee flexion to 110.6 +/- 14.8 N under 110 N of applied load at 15 degrees of flexion. The magnitude of the in situ force in the posterolateral bundle was larger than that in the anteromedial bundle at knee flexion angles between 0 and 45 degrees, reaching a maximum of 75.2 +/- 18.3 N at 15 degrees of knee flexion under an anterior tibial load of 110 N. The magnitude of the in situ force in the posterolateral bundle was significantly affected by knee flexion angle and anterior tibial load in a fashion remarkably similar to that seen in the anterior cruciate ligament. The magnitude of the in situ force in the anteromedial bundle, in contrast, remained relatively constant, not changing with flexion angle. Significant differences in the direction of the in situ force between the anteromedial bundle and the posterolateral bundle were found only at flexion angles of 0 and 60 degrees and only under applied anterior tibial loads greater than 66 N. We have demonstrated the nonuniformity of the anterior cruciate ligament under unconstrained anterior tibial loads. Our data further suggest that in order for the anterior cruciate ligament replacement graft to reproduce the in situ forces of the normal anterior cruciate ligament, reconstruction techniques should take into account the role of the posterolateral bundle in addition to that of the anteromedial bundle.

Adult↗
PubMed1997

Medial collateral knee ligament healing. Combined medial collateral and anterior cruciate ligament injuries studied in rabbits.

We examined the histological appearance and biochemical properties of the healing medial collateral ligament (MCL) of a rabbit knee after combined MCL and anterior cruciate ligament (ACL) injury treated with ACL reconstruction and with or without MCL repair. By so doing, we hoped to understand better our previous bomechanical observations (Ohno et al. 1995) and possibly learn where to focus future investigation into improving the quality of the healing MCL. Ligaments were examined at 6 and 12 weeks of healing. We found healing of all ligaments with hypercellularity and fibroblast elongation along the axis of loading, as expected. Unexpected, however, was the finding of multiple osteophytes in both the repaired and nonrepaired specimens at the medial borders of the joint and at the MCL insertions. These were felt to affect possibly the biomechanics of the MCL by causing stress risers at the point where they undermine the ligament. Biochemically, we demonstrated a correlation between collagen content and hydroxypyridinium crosslinks and modulus of elasticity. While this implies that the modulus is dependent on collagen content and hydroxypyridinium crosslink density, modulus is also probably dependent on other factors such as collagen organization, type and internal structure. Overall, the detailed characterization and correlation between the histological, biochemical, and biomechanical properties of the healing MCL in the severe knee injury model provide insight into the functional behavior of the healing MCL.

Animals↗
PubMed1996

Denuded bowel after recovery from graft-versus-host disease.

Graft-versus-host disease (GVHD) is a common complication of bone marrow transplantation and often involves the gastrointestinal system. It is unclear whether there can be severe enough damage by GVHD to permanently injure the bowel and thereby prevent mucosal regeneration. We describe a patient who had successful treatment of GVHD, but who had such severe scarring of the bowel mucosa that the colonic epithelium could not regenerate even 50 days after biopsy-demonstrated resolution of GVHD. Surveillance cultures and histological analysis indicate that this denudation was not caused by infection or continued GVHD. This is an important observation with implications for monitoring response to GVHD therapy and using rectal biopsy to evaluate GVHD.

Adult↗
PubMed1996

Refining the treatment of women with unstable angina--a randomized, double-blind, comparative safety and efficacy evaluation of Integrelin versus aspirin in the management of unstable angina.

BACKGROUND: Although women typically develop coronary artery disease several years after men, once they have symptomatic disease their thromboembolic complications are worse than in men. The mechanism mediating this gender difference in outcome after thromboembolic events is unknown. We previously studied platelet functions in siblings from patients with premature coronary artery disease. We observed that platelets from women are responsive than their male counterparts. In particular, platelets from women stimulated ex vivo with various agonists bind more fibrinogen molecules than platelets from men. HYPOTHESIS: We hypothesized that in patients with acute coronary events, the control of platelet activity might require stronger antagonists in women than in men. METHODS: To test this hypothesis, we investigated retrospectively the results of a trial on Integrelin in unstable angina. RESULTS: We report that platelet aggregation and Holter-detected ischemic episodes are significantly reduced in women with unstable angina treated with the specific GPIIb-IIIa inhibitor, Integrelin, compared with the standard platelet inhibitor aspirin. In contrast, both platelet aggregation and Holter-detected ischemic events are well controlled in men with unstable angina treated with standard therapy including aspirin. CONCLUSION: Integrelin does provide protection in men, but, in contrast with women, not beyond what can be achieved with aspirin. Our data are consistent with the concept that the platelets from women require stronger and more specific inhibitors to limit their activity, and that platelets may play a more important role in women with acute coronary syndromes than in men. Most important, specific GPIIb-IIIa inhibitors may represent a therapeutic option which provides as much suppression of ischemic events in women as they do in men with coronary artery disease.

Aged↗