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Biomedical subjects

R Emerson

Publications and source records attributed to R Emerson.

At least 19 recordsLinked to original sources
PubMed2007

Cortical abnormalities in epilepsy revealed by local EEG synchrony.

Abnormally strong functional linkage between cortical areas has been postulated to play a role in the pathogenesis of partial epilepsy. We explore the possibility that such linkages may be manifest in the interictal EEG apart from epileptiform disturbances or visually evident focal abnormalities. We analyzed samples of interictal intracranial EEG (ICEEG) recorded from subdural grids in nine patients with medically intractable partial epilepsy, measuring interelectrode synchrony using the mean phase coherence algorithm. This analysis revealed areas of elevated local synchrony, or "hypersynchrony" which had persistent spatiotemporal characteristics that were unique to each patient. Measuring local synchrony in a subdural grid results in a map of the cortical surface that provides information not visually apparent on either EEG or structural imaging. We explore the relationship of hypersynchronous areas to the clinical evidence of seizure localization in each case, and speculate that local hypersynchrony may be a marker of epileptogenic cortex, and may prove to be a valuable aid to clinical ICEEG interpretation.

Adolescent↗
PubMed2005

Type IV hypersensitivity reactions to upper lid gold weight implants-is patch testing necessary?

AIMS: To report two cases of allergic reaction to upper lid gold weight implants in patients with facial nerve palsy and to identify the use of pre-implantation patch testing in predicting gold hypersensitivity. METHODS: One patient who had a positive family history of gold allergy and had undergone previous gold dental restoration underwent patch testing with gold sodium thiosulphate. The gold weight from the same patient was analysed using scanning electron microscopy and energy dispersive X-ray analysis, which can detect surface impurities. Tissue obtained during surgery to remove the gold weight from the second patient was examined histologically. RESULTS: Patch testing in the first patient gave a positive result. Analysis of the gold weight removed from the same patient confirmed 99.99% purity, and hence sensitivity to the gold itself was considered to be the cause of the inflammatory reaction. Histology of tissue taken from the eyelid of the second patient was consistent with type IV hypersensitivity. CONCLUSION: A personal and family history of gold allergy should be looked for before upper eyelid gold weight implantation. Patch testing should be performed for patients where there is doubt about whether gold has been the specific cause of previous allergic reactions, for patients who have undergone previous dental restoration involving gold, or if there is a positive family history of gold allergy.

Aged↗
PubMed2001

Reduced oxidative-stress response in red blood cells from p45NFE2-deficient mice.

p45NF-E2 is a member of the cap 'n' collar (CNC)-basic leucine zipper family of transcriptional activators that is expressed at high levels in various types of blood cells. Mice deficient in p45NF-E2 that were generated by gene targeting have high mortality from bleeding resulting from severe thrombocytopenia. Surviving p45nf-e2(-/-) adults have mild anemia characterized by hypochromic red blood cells (RBCs), reticulocytosis, and splenomegaly. Erythroid abnormalities in p45nf-e2(-/-) animals were previously attributed to stress erythropoiesis caused by chronic bleeding and, possibly, ineffective erythropoiesis. Previous studies suggested that CNC factors might play essential roles in regulating expression of genes that protect cells against oxidative stress. In this study, we found that p45NF-E2-deficient RBCs have increased levels of reactive oxygen species and an increased susceptibility to oxidative-stress-induced damage. Deformability of p45NF-E2-deficient RBCs was markedly reduced with oxidative stress, and mutant cells had a reduced life span. One possible reason for increased sensitivity to oxidative stress is that catalase levels were reduced in mutant RBCs. These findings suggest a role for p45NF-E2 in the oxidative-stress response in RBCs and indicate that p45NF-E2 deficiency contributes to the anemia in p45nf-e2(-/-) mice. (Blood. 2001;97:2151-2158)

Anemia, Hypochromic↗
PubMed2001

Targeting interleukin-2 as a treatment for psoriasis.

Interleukin (IL)-2 is known to play a key role in the pathophysiology of psoriasis by activating T-cells. In recent years, therapies have been developed to specifically prevent T-cell activation by blocking the production of IL-2 or by inhibiting its action. These new therapies are discussed.

Animals↗
PubMed2000

A modified transorbital baboon model of reperfused stroke.

BACKGROUND AND PURPOSE: Although pathophysiological studies of focal cerebral ischemia in nonhuman primates can provide important information not obtainable in rodent models, primate experimentation is limited by considerations of cost, availability, effort, and ethics. A reproducible and quantitative model that minimizes the number of animals necessary to detect differences between treatment groups is therefore crucial. METHODS: Eight male baboons (weight, 22+/-2 kg) underwent left transorbital craniectomy followed by 1 hour of temporary ipsilateral internal carotid artery occlusion at the level of the anterior choroidal artery together with bilateral temporary occlusion of both anterior cerebral arteries (A1) proximal to the anterior communicating artery. A tightly controlled nitrous oxide-narcotic anesthetic allowed for intraoperative motor evoked potential confirmation of middle cerebral artery (MCA) territory ischemia. Animals survived to 72 hours or 10 days if successfully self-caring. Outcomes were assessed with a 100-point neurological grading system, and infarct volume was quantified by planimetric analysis of both MRI and triphenyltetrazolium chloride-stained sections. RESULTS: Infarction volumes (on T2-weighted images) were 32+/-7% (mean+/-SEM) of the ipsilateral hemisphere, and neurological scores averaged 29+/-9. All animals demonstrated evidence of hemispheric infarction, with damage evident in both cortical and subcortical regions in the MCA vascular territory. Histologically determined infarction volumes differed by <3% and correlated with absolute neurological scores (r=0.9, P:=0.003). CONCLUSIONS: Transorbital temporary occlusion of the entire anterior cerebral circulation with strict control of physiological parameters can reliably produce reperfused MCA territory infarction. The magnitude of the resultant infarct with little interanimal variability diminishes the potential number of animals required to distinguish between 2 treatment regimens. The anatomic distribution of the infarct and associated functional deficits offer comparability to human hemispheric strokes.

Animals↗
PubMed1999

Combination treatment with methotrexate and cyclosporin for severe recalcitrant psoriasis.

An increasingly important approach to the management of patients with severe psoriasis is the concurrent use of two systemic treatments. Previous guidelines have advised against the use of methotrexate and cyclosporin in combination. We report the successful use of a combination of methotrexate and cyclosporin in the treatment of 19 patients with severe, recalcitrant psoriasis, 15 of whom had psoriatic arthropathy. Most patients had previously received two or more systemic treatments. Before combination treatment was started nine of the patients were taking methotrexate and 10 were taking cyclosporin at the maximum tolerated doses. The duration of combination treatment was bimodally distributed, with seven patients having short-term treatment (mean +/- SD duration 18. 9 +/- 15.7 weeks) and 12 patients having long-term treatment (mean +/- SD duration 193.2 +/- 160.6 weeks). Those patients who received short-term treatment did not develop any evidence of toxicity from either agent. Of those patients on long-term treatment, three developed mild impairment of renal function that returned to normal following a reduction in dose of cyclosporin, and three had impairment of renal function (following long-term cyclosporin monotherapy) that improved, but did not normalize, following a reduction in dose of cyclosporin. In each case, combination treatment for psoriasis resulted in good control of both skin and joint problems using lower doses of each agent than would have been used for monotherapy. We conclude that the combination of methotrexate and cyclosporin is an effective treatment for this group of patients.

Adult↗
PubMed1997

Managing atopic eczema: the needs of children.

Atopic eczema is a common inflammatory condition of the skin. The disability and psychosocial impact of atopic eczema can be considerable. Existing dermatology clinics usually do not provide the time and the educational facilities essential for children with atopic eczema and their families.

Ambulatory Care Facilities↗
PubMed1997

Managing atopic eczema: running a specialist clinic.

Specialist management of children with atopic eczema is directed towards education, treatment and reassurance of the child and family. A specialist clinic can tailor care to the individual needs of those attending. Specialist clinics should be constantly evaluated and developed to cope with the changing demands and needs of patients with atopic eczema.

Child↗
PubMed1997

Intra-operative electrocochleography in stapedectomy and ossicular reconstruction.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of intraoperative electrocochleography (ECOG) in predicating the postoperative hearing improvement in surgery for conductive hearing loss. STUDY DESIGN: This study was a prospective study of 22 patients undergoing intraoperative electrocochleography during a stapedectomy. SETTING: The study was performed in a tertiary referral center. PATIENTS: Intraoperative electrocochleography was performed in 22 patients 27-73 years of age undergoing a stapedectomy for otosclerosis under general anesthesia. INTERVENTION: For each patient, the N1 threshold to click stimulation was measured intraoperatively, before and after the reconstruction. MAIN OUTCOME MEASURES: The intraoperative ECOG thresholds were compared with the pre and postoperative audiograms. RESULTS: Postreconstruction ECOG's demonstrated improvements in the N1 threshold in 19 cases, and were unchanged in 1 case. In each of these cases, improvement in the intraoperative N1 threshold corresponded with improvement in the postoperative audiogram compared with the preoperative studies. In two other cases the postreconstruction ECOG was nearly unobtainable, despite improved hearing postoperatively. CONCLUSION: Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstructions as in stapedectomies. We speculate that intraoperative ECOG may allow the surgeon to "fine tune" the reconstruction to optimize the hearing results.

Adult↗
PubMed1996

Low ceruloplasmin levels during recovery from major burn injury: influence of open wound size and copper supplementation.

Copper (Cu) status is often judged by the plasma level of its chief transport protein, ceruloplasmin (Cp). Only copper deficiency and heredity are known to decrease circulating Cp. Cp is an acute-phase responsive protein in trauma and it is also induced by Cu supplementation. Despite this, plasma concentrations of Cp remain low during the acute recovery from major burn injury. The high provision of vitamin C typically used in burn patients may influence these observations when an indirect oxidase activity assay is used. We employed a radial immunodiffusion (RID) assay specific for the Cp protein as well as an indirect oxidase assay for Cp in a series of 11 burned children who were supplemented with both Cu and vitamin C, either enterally or parenterally. Our findings confirm that low Cp is a characteristic of the acute recovery from major burns. The oxidase assay is shown to be valid for very low Cp levels even during high vitamin C provision. When these data are combined with our previously reported series, a strong relationship between the size of the open wound area and the amount of circulating Cp is demonstrated. Copper supplementation by either the enteral or parenteral routes is only marginally successful in restoring Cp toward normal levels.

Adolescent↗
PubMed1996

Treatment of severe atopic dermatitis in childhood with cyclosporin.

Cyclosporin has been shown to be effective in the treatment of adult atopic dermatitis, but there are no clinical trials evaluating its use in childhood. Atopic dermatitis is more common in children and the severe form can be associated with considerable morbidity. We report on 18 children with severe refractory atopic dermatitis who have been treated with cyclosporin on an open basis. The drug was given at an initial daily dose of 5 or 6 mg/kg and in some patients the dose was reduced according to response. Sixteen patients showed a good or excellent response to treatment, one a moderate response and one patient failed to improve. The treatment was well tolerated and there were no significant changes in serum creatinine or blood pressure. Long remission after withdrawal of treatment was seen in some patients, although most relapsed within a few weeks. We suggest that cyclosporin is an effective and safe short-term treatment for severe atopic dermatitis in childhood.

Adolescent↗
PubMed1992

Fetal alcohol syndrome and fatty acid ethyl esters.

Fetal alcohol syndrome is the leading known cause of mental retardation. The syndrome, defined as growth retardation, midface hypoplasia, and neurologic dysfunction, represents only part of the spectrum of fetal alcohol effects. The biochemical mechanism of teratogenesis is unknown. In adults, metabolites of ethanol, FAEE, are known to accumulate in major organs. The formation of FAEE is catalyzed by a family of enzymes, FAEE synthases. Our hypothesis is that accumulation of FAEE in the embryo results in fetal alcohol syndrome. We have developed assays for FAEE and FAEE synthase activity using mg of tissue. Using these assays, we have shown the following: Human placenta, mouse placenta, heart, and liver are active in catalyzing the formation of FAEE. One h after maternal ethanol administration on gestational d 14, mouse placenta and fetuses accumulated significant quantities of FAEE. The fatty acid incorporated into FAEE was tissue dependent. Tissues from pregnant animals given ethanol on gestational d 7 showed persistence of FAEE on gestational d 14. We conclude that: 1) human and mouse placentas have significant FAEE synthase activity, 2) mouse heart, liver, placenta, and fetal tissues accumulate significant amounts of FAEE after maternal ethanol exposure, 3) there is tissue specificity for the fatty acid incorporated into FAEE, and 4) FAEE may persist for 7 d in placentas. These results provide a basis for further research into the role of FAEE in the development of fetal alcohol syndrome.

Acyltransferases↗
PubMed1991

Median nerve somatosensory evoked potentials in patients with lacunar and other small subcortical strokes.

We recorded median nerve somatosensory evoked potentials (SSEPs) in 42 patients with small subcortical strokes associated with lacunar syndromes. Seventeen patients had abnormal SSEPs. The P22 component was most often affected; changes in N20 and N18 were less common. Four patients with pure motor strokes (PMS) had abnormal SSEPs. Abnormalities of P22 correlated best with motor findings; those of N20 with sensory signs and symptoms. Similar SSEP abnormalities were produced by lesions in various locations. P22 and N20 abnormalities occurred independently and together. We conclude: (1) abnormal SSEPs are common in patients with small subcortical strokes associated with lacunar syndromes, including pure motor stroke; (2) P22 and N20 have separate cortical generators; and (3) P22 may be generated within sensory pathways which are adjacent to or influenced by motor pathways.

Adult↗
PubMed1991

Theoretical and practical performance of magnetic stimulators and coils.

The diagnostic use of magnetic brain stimulation has not been extensive because of several technical drawbacks. These include the relatively low field strength and low repetition rate of available stimulators, design problems which can be resolved with the construction of stronger and faster magnetic stimulators. The present study details the design of a magnetic stimulator in two phases: energy storage and switching current; and the head or 'probe' design. The theoretical and practical implications of these design factors are discussed, and design effects on safety limits and stimulation parameters are also considered.

Electric Conductivity↗
PubMed1988

Primary lateral sclerosis. A clinical diagnosis reemerges.

Adults with slowly progressive noninherited gait disorders may show no abnormalities on examination other than signs implicating the corticospinal tracts. That is the syndrome of "primary lateral sclerosis" (PLS), a clinical diagnosis that has been avoided because it is a diagnosis of exclusion, proven only at autopsy. Now, modern technology can exclude other disorders that can cause the syndrome with an accuracy of about 95%. That serves to eliminate the following: compressive lesions at the foramen magnum or cervical spinal cord, multiple sclerosis, amyotrophic lateral sclerosis, Chiari malformation, syringomyelia, biochemical abnormality, and persistent infection with human immunodeficiency virus or human T-lymphotrophic virus type I. We studied three autopsy-proved cases of PLS; six living patients in whom PLS was diagnosed clinically after comprehensive evaluations that excluded the alternative diagnoses; and two patients with this syndrome of PLS and antibodies to human immunodeficiency virus seropositivity that clinically resembled PLS. Primary lateral sclerosis is now a respectable and permissible diagnosis.

Adult↗