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Biomedical subjects

R B Bell

Publications and source records attributed to R B Bell.

At least 19 recordsLinked to original sources
PubMed2004

The effect of immunomodulatory treatment on multiple sclerosis fatigue.

OBJECTIVE: To assess the effects of glatiramer acetate and beta interferon on fatigue in multiple sclerosis. METHODS: Fatigue was measured at baseline and six months using the fatigue impact scale (FIS). Groups (glatiramer acetate and beta interferon) were evaluated for the proportion improved, using Fisher's exact test. Logistic regression analysis assessed the relation between treatment group and improvement and controlled for confounding variables. RESULTS: Six month paired FIS assessments were available for 218 patients (76% female). Ages ranged between 19 and 61 years, with 86% having relapsing-remitting disease. Glatiramer acetate was used by 61% and beta interferon by 39%. At baseline, total FIS and subscale scores were comparable in the two groups. More patients improved on glatiramer acetate than on beta interferon on total FIS (24.8% v 12.9%, p = 0.033; adjusted odds ratio = 2.36, 95% confidence interval 1.03 to 5.42), and on physical (28.6% v 14.1%, p = 0.013) and cognitive subscales (21.1% v 10.6%, p = 0.045). Logistic regression analysis confirmed the association between glatiramer acetate use and improved fatigue, after accounting for baseline group differences. CONCLUSIONS: The odds of reduced multiple sclerosis fatigue were around twice as great with glatiramer acetate treatment as with beta interferon. Confirmation of this result is required.

Adjuvants, Immunologic↗
PubMed2001

Skeletal advancement for the treatment of obstructive sleep apnea in children.

OBJECTIVE: Maxillomandibular advancement is curative for some adult patients with obstructive sleep apnea (OSA). Little is known, however, about the efficacy of this treatment in children. The purpose of this retrospective analysis is to assess the clinical outcomes of children with medically refractory OSA who were treated with a variety of procedures to advance the maxillofacial skeleton. METHODS: The records of eight children with OSA (five boys and three girls; mean age, 8.6 years; range, 2 to 17 years) were reviewed. Six children had identifiable syndromes associated with micrognathia, one child had mandibular ankylosis, and one child was nonsyndromic. In five of the children, conventional medical and surgical treatment of OSA had failed; therefore, these children were considered tracheostomy candidates. The remaining three children had had tracheostomies placed in infancy. Specific signs and symptoms with regard to each patient's OSA were identified and recorded. Bronchoscopy was performed preoperatively to evaluate the airway and localize the site of obstruction and again postoperatively if the patient's signs and symptoms recurred. Oxygen saturation and sleep patterns were monitored overnight in the five patients without tracheostomies, revealing a mean apnea index of 25.3 (range, 2.0 to 60.0) and mean lowest desaturation of 73% (range, 62% to 77%). All patients underwent a variety of skeletal procedures to advance the mandible, maxilla, and/or chin. OUTCOME MEASURES: Criteria for success after treatment were twofold: (1) decannulation and (2) cessation or improvement in symptoms facilitating avoidance of tracheostomy. Criteria for failure, likewise, were (1) inability to decannulate and (2) recurrence or nonimprovement in symptoms necessitating tracheostomy. RESULTS: To date, with a mean follow-up time of 7.2 years (range, 19 months to 19 years), the treatment of four of the eight children in our population can be considered a success. Two of the three children with previously placed tracheostomies were able to be decannulated within days of surgery and experienced no further signs or symptoms of OSA. Two other children experienced complete cessation of clinical signs and symptoms and elimination of previous oxygen requirements. Of the four patients in whom treatment failed, three had transient improvement (mean, 6 months) and, despite skeletal stability, eventually experienced relapse of symptoms: one patient with Down syndrome and tracheobronchomalacia required subsequent tracheostomy; the second had a central obstructive component and underwent a ventriculoperitoneal shunt for treatment of a Chiara I malformation; and the third experienced relapse of symptoms due to lack of mandibular growth. The fourth child could not be decannulated because of accompanying tracheal and laryngeal malacia. CONCLUSIONS: Skeletal advancement can be an effective treatment for medically refractory OSA in children. Success, however, is dependent not only on skeletal position but also on neuromuscular adaptation. Bronchoscopy is the most valuable diagnostic and predictive tool.

Adolescent↗
PubMed2000

Osteogenesis imperfecta and orthognathic surgery: case report with long-term follow-up.

Osteogenesis imperfecta (OI) is the product of the abnormal synthesis and/or production of Type I collagen. Successful surgical management of extremity and spinal skeletal problems secondary to OI is documented in the orthopedic literature. Reports of successful facial skeletal surgery in all types of OI are encouraging. The purpose of this paper is to report on the long-term results of an orthognathic surgery patient successfully treated to correct a severe dentofacial deformity. The patient underwent an uncomplicated Le Fort I osteotomy with homologous interpositional bone grafts to advance and inferiorly reposition the maxilla. Clinically, the patient appeared to heal without difficulty, and a stable Class I skeletal and dental relationship was achieved. Nine years after surgery, the patient has a Class I occlusion, with maintenance of his facial height and skeletal relationship. Craniomaxillofacial surgery can be predictably performed in patients with OI as long as the surgeon maintains strict adherence to proper surgical technique and bears in mind the deficiencies of bone density and other possible medical complications.

Adult↗
PubMed1996

A full genome search in multiple sclerosis.

The aetiology of multiple sclerosis (MS) is uncertain. There is strong circumstantial evidence to indicate it is an autoimmune complex trait. Risks for first degree relatives are increased some 20 fold over the general population. Twin studies have shown monozygotic concordance rates of 25-30% compared to 4% for dizygotic twins and siblings. Studies of adoptees and half sibs show that familial risk is determined by genes, but environmental factors strongly influence observed geographic differences. Studies of candidate genes have been largely unrewarding. We report a genome search using 257 microsatellite markers with average spacing of 15.2 cM in 100 sibling pairs (Table 1, data set 1 - DS1). A locus of lambda>3 was excluded from 88% of the genome. Five loci with maximum lod scores (MLS) of >1 were identified on chromosomes 2, 3, 5, 11 and X. Two additional data sets containing 44 (Table 1, DS2) and 78 sib pairs (Table 1, DS3) respectively, were used to further evaluate the HLA region on 6p21 and a locus on chromosome 5 with an MLS of 4.24. Markers within 6p21 gave MLS of 0.65 (non-significant, NS). However, D6S461, just outside the HLA region, showed significant evidence for linkage disequilibrium by the transmission disequilibrium test (TDT), in all three data sets (for DS1 chi2 = 10.8, adjusted P < 0.01)(DS2 and DS3 chi2 = 10.9, P < 0.0005), suggesting a modest susceptibility locus in this region. On chromosome 5p results from all three data sets (222 sib pairs) yielded a multipoint MLS of 1.6. The results support genetic epidemiological evidence that several genes interact epistatically to determine heritable susceptibility.

Chromosome Mapping↗
PubMed1995

The relationship of TAP1 and TAP2 dimorphisms to multiple sclerosis susceptibility.

Transporters associated with antigen processing and presentation (TAP1 and TAP2) have been considered candidate genes in MS susceptibility based on evidence from experimental animal models confirming antigenic peptide selection by transporter polymorphisms and by the proximity of these transporter genes to the DR- and DQ-associated alleles known to confer disease risk in man. We report here an association study examining the influence of TAP gene polymorphisms on MS susceptibility in a Canadian patient population. Our results do not support a role for the five polymorphisms examined in the etiology of this disease.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Spinal cord injury in youth.

To identify special characteristics of the pediatric spinal cord-injured (SCI) population, we analyzed a database of 1,770 traumatic SCI patients; 88 (5%) fell into the two pediatric subgroups: 0-12 years (n = 26) and 13-15 years (n = 62) at time of injury. Differences between age groups were identified with regard to demographics, neurologic characteristics, associated injuries and complications, and management. Mode level of bony injury was C2 in preteens, C4 in teens, and C4-C5 in adults. Scoliosis developed far more frequently in children, particularly preteens (23%), than in adults (5%). Violent etiologies, predominantly gunshots, accounted for a disproportionate share of injuries to preteens (19%) and African-Americans (28%), as compared with adults (12%) and Caucasians (7%). This last finding underscores the urgent need to mount a response to the nationwide proliferation of gunshot-related SCI in children and minorities.

Adolescent↗
PubMed1993

Diverse T cell receptor V beta gene usage in the central nervous system in experimental allergic encephalomyelitis.

The repertoire of TCR V beta genes transcribed and expressed within the central nervous system was determined in mice with experimental allergic encephalomyelitis. Disease was induced in (PL/J x SJL/)F1 mice by immunizing with myelin basic protein-acetylated peptide 1-11, and mice were sacrificed at intervals from day 3 postimmunization to 3 wk after recovery from disease. Transcription of V beta genes was determined by reverse transcriptase polymerase chain reaction on RNA extracted from spinal cord, and expression of the V beta gene products was detected by immunohistochemistry with mAb specific for various V beta proteins. Multiple V beta genes were found to be transcribed and expressed in the central nervous system starting 7 days after immunization, and continuing up to 3 wk after clinical recovery. Preferential utilization of a single TCR V beta gene was not detected in the central nervous system at any time in the course of disease.

Animals↗
PubMed1991

Trimolecular interactions in experimental autoimmune demyelinating disease and prospects for immunotherapy.

Experimental allergic encephalomyelitis (EAE) is a T cell mediated model of demyelinating disease that develops as a result of an autoimmune response to the myelin structural antigen, myelin basic protein (MBP). Much information has accumulated on the nature of trimolecular interactions which lead to the activation of self-reactive T lymphocytes in this disorder. Many parallels exist in the etiopathogenesis of EAE and multiple sclerosis (MS). Based upon these similarities selective immunotherapy that targets either class II molecules of the major histocompatibility complex or T cell receptor variable region genes will be described for EAE with consideration given to application of these principles in MS.

Amino Acid Sequence↗
PubMed1990

Limited heterogeneity of rearranged T-cell receptor V alpha transcripts in brains of multiple sclerosis patients.

The identification of activated T cells in the brain of individuals with multiple sclerosis (MS) indicates that these cells are critical in the pathogenesis of this disease. In an attempt to elucidate the nature of the lymphocytic infiltration, we used the polymerase chain reaction to amplify T-cell antigen receptor (TCR) V alpha sequences from transcripts derived from MS brain lesions. In each of three MS brains, only two to four rearranged TCR V alpha transcripts were detected. No V alpha transcripts could be found in control brains. Sequence analysis of transcripts encoded by the V alpha 12.1 region showed rearrangements to a limited number of J alpha region segments. These results imply that TCR V alpha gene expression in MS brain lesions is restricted.

Base Sequence↗
PubMed1990

Electron transfer flavoprotein: ubiquinone oxidoreductase (ETF:QO) deficiency in an adult.

A 19-year-old woman with mild myopathic symptoms from age 6 and fasting intolerance presented with a Reye-like syndrome and a myopathy. Investigations disclosed a lipid storage myopathy, type II glutaric acidemia, and carnitine deficiency in skeletal muscle. Riboflavin and carnitine treatment corrected the metabolic abnormalities and she improved clinically. She later died from pulmonary complications secondary to aspiration. Subsequent studies established electron transfer flavoprotein: ubiquinone oxidoreductase (ETF:QO) deficiency (fibroblast ETF:QO activity was 2.9 mU/mg, normal range is 14.1 +/- 3.8 mU/mg) as the cause of her illness. This is the first documented case of ETF:QO diagnosed in an adult.

Acidosis↗
PubMed1989

Neuropathy with onion bulb formations and pure motor manifestations.

A thirty-eight-year-old man presented with a six year history of symptoms resembling an anterior horn cell disorder. There was progressive upper extremity wasting and weakness in the absence of sensory complaints. Electrophysiologic abnormalities were confined to motor nerve conduction and indicated a demyelinating process involving the brachial plexus and major proximal upper extremity nerve trucks bilaterally. Biopsy of the proximal right ulnar nerve revealed changes suggesting a chronic demyelinating process, and onion-bulb formations were present. Immunohistochemical staining for S-100 protein was positive in the cells comprising the onion-bulbs, indicating a Schwann cell, not a perineurial origin of these cells. After 8 years, symptoms have failed to appear in the lower limbs. Recent reports in the literature have begun to delineate the syndrome, which appears to represent an unusual, localized or multifocal, sometimes inflammatory, clinically benign neuropathy that can mimic motor neuron disease in its earlier stages. We report the first such case with underlying pathology.

Adult↗