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Biomedical subjects

C E Jackson

Publications and source records attributed to C E Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1998

Vocal cord and pharyngeal weakness with autosomal dominant distal myopathy: clinical description and gene localization to 5q31.

Distal myopathy refers to a heterogeneous group of disorders in which the initial manifestations are weakness and atrophy of the hands and feet. We report a family segregating an autosomal dominant distal myopathy, with multiple affected individuals in whom vocal cord and pharyngeal weakness may accompany the distal myopathy, without involvement of the ocular muscles. To our knowledge, this pedigree displays a distinct distal myopathy with the added features of pharyngeal and vocal cord dysfunction (VCPDM) that has not been previously reported. We mapped the MPD2 gene for VCPDM to chromosome 5q within a 12-cM linkage interval between markers D5S458 and D5S1972 in a large pedigree (a maximum LOD score of 12.94 at a recombination fraction of 0 for D5S393) and combined genome screening and DNA pooling successfully adapted to fluorescent markers. This technique provides for the possibility of fully automated genome scans.

Adult↗
PubMed1998

Diabetic neuropathic cachexia: report of a recurrent case.

Diabetic neuropathic cachexia is an uncommon peripheral neuropathy associated with diabetes mellitus and characterised by profound weight loss and painful dysaesthesias over the limbs and trunk. The pathophysiological basis of this disorder remains unknown and there have been no published cases of recurrent episodes. A hispanic man who experienced two episodes of diabetic neuropathic cachexia over a seven year period is described.

Adult↗
PubMed1998

Primary hyperparathyroidism and ALS: is there a relation?

BACKGROUND: An association between primary hyperparathyroidism (PHP) and amyotrophic lateral sclerosis (ALS) has been noted; however, a causal relation between these disorders has not been confirmed. PATIENTS/METHODS: We report five patients (three men, two women) meeting El Escorial criteria for ALS who also had PHP. In three patients, the diagnosis of PHP was made during the laboratory evaluation for motor neuron disease, and in one patient, the diagnosis of PHP preceded the onset of weakness by 5 months and in another by 2 years. Serum calcium levels in all five patients were elevated, ranging from 11.2 to 12.8 mg/dL (normal, <10.4 mg/dL), as were levels of parathyroid hormone (PTH). RESULTS: All five patients underwent parathyroid adenoma resection with subsequent normalization of serum calcium and PTH levels. Each patient had progressive weakness resulting in death 1 to 3 years following parathyroidectomy. CONCLUSION: Resection of parathyroid adenomas in patients meeting El Escorial criteria for ALS did not alter the course of ALS. PHP and ALS appear to be coexisting but unrelated disorders.

Adenoma↗
PubMed1998

The wide spectrum of myofibrillar myopathy suggests a multifactorial etiology and pathogenesis.

BACKGROUND: Myofibrillar myopathy (MFM) is characterized by nonhyaline lesions (foci of myofibrillar destruction) and hyaline lesions (cytoplasmic inclusions composed of compacted myofibrillar residues) on light and electron microscopy. Immunocytochemistry demonstrates the abnormal expression of desmin and numerous other proteins. The clinical, laboratory, and histologic features of MFM are heterogeneous, making a diagnosis difficult. RESULTS: We diagnosed eight patients with MFM over the preceding 3 years. MFM was inherited in an autosomal dominant pattern in one patient, developed sporadically in five patients, and was induced by an experimental chemotherapy, Elinafide (Knoll, Parsippany, NJ), in two patients. Age at onset ranged from 14 to 64 years. The pattern of weakness was variable but involved proximal and distal muscles. Five patients had evidence of a cardiomyopathy. Electromyography demonstrated muscle membrane instability and small, polyphasic motor unit potentials. Serum creatine kinase levels were normal to moderately elevated (<10x normal). Light and electron microscopy demonstrated the characteristic pattern of nonhyaline and hyaline lesions and the associated abnormalities on immunocytochemistry. CONCLUSIONS: Patients demonstrate a wide spectrum of clinical, laboratory, and histologic abnormalities. Chemotherapy-induced MFM has abnormalities on immunocytochemistry similar to the those of hereditary and sporadic cases. The pathogenesis of MFM is likely heterogeneous. However, MFM is distinctive in that it can preferentially affect distal muscles and has a frequent association with cardiomyopathy. The cardiomyopathy may be amenable to treatment with pacemaker insertion or cardiac transplantation.

Adult↗
PubMed1997

Chronic relapsing brachial plexus neuropathy with persistent conduction block.

Idiopathic brachial plexus neuropathy (BPN) is an immune-mediated disorder characterized by an acute onset of painful weakness in one or both upper extremities. The course is usually monophasic with gradual improvement over months; however, occasionally BPN can recur. Electrophysiologic studies suggest the pathogenesis is primarily axonal in the majority of cases. We describe an unusual case of BPN in which the patient had a chronic and relapsing course of painless weakness associated with conduction blocks and other electrophysiologic features of demyelination across the brachial plexus. The patient improved following treatment with intravenous immunoglobulin. The neuropathy falls within the spectrum of chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy.

Action Potentials↗
PubMed1997

The activin receptor-like kinase 1 gene: genomic structure and mutations in hereditary hemorrhagic telangiectasia type 2.

The activin receptor-like kinase 1 gene (ALK-1) is the second locus for the autosomal dominant vascular disease hereditary hemorrhagic telangiectasia (HHT). In this paper we present the genomic structure of the ALK-1 gene, a type I serine-threonine kinase receptor expressed predominantly in endothelial cells. The coding region is contained within nine exons, spanning < 15 kb of genomic DNA. All introns follow the GT-AG rule, except for intron 6, which has a TAG/gcaag 5' splice junction. The positions of introns in the intracellular domain are almost identical to those of the mouse serine-threonine kinase receptor TSK-7L. By sequencing ALK-1 from genomic DNA, mutations were found in six of six families with HHT either shown to link to chromosome 12q13 or in which linkage of HHT to chromosome 9q33 had been excluded. Mutations were also found in three of six patients from families in which available linkage data were insufficient to allow certainty with regard to the locus involved. The high rate of detection of mutations by genomic sequencing of ALK-1 suggests that this will be a useful diagnostic test for HHT2, particularly where preliminary linkage to chromosome 12q13 can be established. In two cases in which premature termination codons were found in genomic DNA, the mutant mRNA was either not present or present at barely detectable levels. These data suggest that mutations in ALK-1 are functionally null alleles.

Activin Receptors↗
PubMed1997

Cognitive impairment in the Amish: a four county survey.

BACKGROUND: The prevalence of probable dementia was determined in a rural, homogeneous community of Amish individuals in the Midwestern USA. The Amish are a genetically isolated group with a low level of formal education (< or = 8 years) and few exposures to modern life, who live in intergenerational setting and have strong social support networks. METHODS: Using community directories, trained interviewers administered the Mini Mental State Examination (MMSE) and a medical history survey to all Amish over 64 years old in a four county area. Individuals with scores < 27 (out of a maximum of 30 points) were given additional neuropsychological tests. Results were reviewed by a neuropsychologist and subjects were classified with regard to probable cognitive impairment. RESULTS: The MMSE scores were inversely related with age and directly with education. The Amish have higher MMSE scores than reported for the general US population. The overall prevalence of probable cognitive impairment for those over 64 years was 6.4%. The prevalence increased with age and lower education and was lowest among married individuals. CONCLUSIONS: The MMSE scores among the Amish were higher than the general population despite their low level of formal education. The lower level of cognitive impairment among the Amish could reflect a lack of inherited susceptibility to dementing diseases, or environmental factors characteristic of their traditional lifestyle. Even among this population with < or = 8 years of formal education, education may protect against cognitive impairment.

Age Distribution↗
PubMed1997

Genomic sequencing of DPC4 in the analysis of familial pancreatic carcinoma.

A first-degree relative with pancreatic cancer is found in 5% to 10% of patients with pancreatic carcinomas, suggesting an inherited predisposition for this neoplasm. The recently identified DPC4 tumor suppressor gene is a strong candidate for the gene responsible for the familial form of pancreatic carcinoma. DPC4 was identified in a consensus area of homozygous deletion in pancreatic carcinomas, and it is biallelically inactivated in approximately 50% of sporadic pancreatic carcinomas. The coding sequence of this gene is 1660 nucleotides in length, covering 11 exons. We describe optimized primers and conditions used in polymerase chain reaction and cycle sequencing of the entire DPC4 coding sequence of 25 individuals (eight with pancreatic carcinoma) from 11 kindreds with a familial aggregation of pancreatic carcinoma. No mutations in the coding sequences of the DPC4 gene were found; hence, it appears that germline mutations in DPC4 cannot account for many of the familial aggregations of pancreatic carcinoma.

Carcinoma↗
PubMed1997

Evaluation of neuromuscular symptoms in veterans of the Persian Gulf War.

OBJECTIVE: To comprehensively evaluate complaints of muscle fatigue, weakness, and myalgias in Persian Gulf veterans (PGV). BACKGROUND: Approximately 700,000 American troops were deployed to the Persian Gulf during Desert Shield and Desert Storm. Upon return from the Gulf, some PGV developed unexplained illnesses, and special referral centers were established for the evaluation of these patients. Among the most common symptoms of these PGV are fatigue, weakness, and myalgias. An Institute of Medicine committee recommended further exploration into the possible etiologies of these complaints. METHODS: Twenty PGV with severe muscle fatigue, weakness, or myalgias that interfered with their daily activities were referred for an extensive prospective neuromuscular evaluation. Routine laboratory studies included serum creatine kinase (CK), erythrocyte sedimentation rate, thyroid function tests, and exercise forearm tests. All patients received nerve conduction studies (NCS), repetitive nerve stimulation, quantitative and single-fiber electromyography (EMG), and muscle biopsies. RESULTS: Manual muscle strength examinations were normal in all patients. Six patients had mildly elevated CKs (range 223 to 768 IU/l); otherwise, laboratory tests were unremarkable. NCS were normal except in 2 patients with carpal tunnel syndrome. Quantitative EMGs were normal. One patient had mildly increased jitter on single-fiber EMG. Muscle biopsies demonstrated minor nonspecific abnormalities in 5 patients (i.e., increased central nuclei, rare necrotic fibers, tubular aggregates). CONCLUSIONS: Despite severe subjective symptoms, most of our patients had no objective evidence of neuromuscular disease. Mildly increased CKs or nonspecific histologic abnormalities on muscle biopsy were evident in 8 patients but were not believed to be clinically significant in most. We found no evidence of a specific neuromuscular disorder in any patient. Exposures to toxins during the Persian Gulf War were not likely responsible for our patients' symptoms.

Action Potentials↗
PubMed1997

Electrophysiologic findings in multifocal motor neuropathy.

We performed detailed electrophysiologic studies on 16 patients with clinically defined multifocal motor neuropathy and found a wide spectrum of demyelinating features. Only five patients (31%) had conduction block in one or more nerves. However, in 15 patients (94%) at least one nerve showed other features of demyelination. We also noted a significant degree of superimposed axonal degeneration in 15 patients. Eight patients (50%) had individual nerves with pure axonal injury, despite the presence of demyelinating features in other nerves. Antiganglioside antibodies were elevated in four of five patients with conduction block and five of 11 patients without conduction block. We conclude that multifocal motor neuropathy is characterized electrophysiologically by a wide spectrum of axonal and demyelinating features. Diagnostic criteria requiring conduction block may lead to underdiagnosis of this potentially treatable neuropathy.

Adult↗
PubMed1997

Multiple independent molecular etiology for limb-girdle muscular dystrophy type 2A patients from various geographical origins.

Limb-girdle muscular dystrophies (LGMDs) are a group of neuromuscular diseases presenting great clinical heterogeneity. Mutations in CANP3, the gene encoding muscle-specific calpain, were used to identify this gene as the genetic site responsible for autosomal recessive LGMD type 2A (LGMD2A; MIM 253600). Analyses of the segregation of markers flanking the LGMD2A locus and a search for CANP3 mutations were performed for 21 LGMD2 pedigrees from various origins. In addition to the 16 mutations described previously, we report 19 novel mutations. These data indicate that muscular dystrophy caused by mutations in CANP3 are found in patients from all countries examined so far and further support the wide heterogeneity of molecular defects in this rare disease.

Adolescent↗
PubMed1996

Germline BRCA2 gene mutations in patients with apparently sporadic pancreatic carcinomas.

Germline mutations in BRCA2 predispose carriers to the development of breast, ovarian, and a variety of other cancers. The original localization of the BRCA2 gene was aided by its homozygous deletion in a pancreatic carcinoma; indeed, an excess of pancreatic carcinoma has been seen in some BRCA2 cancer families. To determine the involvement of BRCA2 in pancreatic carcinomas, we screened for BRCA2 alterations in an unselected panel of 41 adenocarcinomas of the pancreas (30 pancreatic adenocarcinoma xenografts and 11 pancreatic cancer cell lines). Of the 15 (27%) that had allelic loss at the BRCA2 locus, 4 (9.8%) had abnormalities in the second allele upon screening of the entire BRCA2 gene by in vitro synthesized protein assay. Three of the four mutations were considered germline in origin (7.3% overall; two were confirmed in normal tissue, and one was the 6174delT mutation from the pancreatic cancer cell line CAPAN-1, for which normal tissue was unavailable). The identification of two 6174delT mutations in this series prompted us to evaluate the prevalence of this mutation in an overlapping consecutive series of 245 patients who underwent pancreatoduodenectomy for adenocarcinoma of the pancreas. Sequence analysis of this limited region of the gene identified two additional mutations: (a) one additional germline 6174delT mutation (2 of 245, 0.8% overall); and (b) a second nearby germline 6158insT mutation. One of the patients with a germline mutation had a single relative with breast cancer, and another had a single relative with prostate cancer. None had a family history of pancreatic cancer. The incidence of germline BRCA2 mutations in apparently sporadic pancreatic cancer may be at least as high as in breast or ovarian cancer. Our results suggest that some familial risks for carcinoma will be evident only through a population-based application of gene screening techniques because a low disease penetrance of the germline mutations in some families often evades clinical suspicion.

Adenocarcinoma↗
PubMed1996

Evidence against chronic antigen-specific T lymphocyte activation in myasthenia gravis.

Myasthenia gravis (MG) is an antigen-specific autoimmune disease caused by antibodies against acetylcholine receptors (AChR) at the post-synaptic membrane of the neuromuscular junction. Clinical and immunological data imply the involvement of AChR-specific T lymphocytes as helper cells for autoantibody production. Direct data to support this hypothesis, however, remain sparse. In the present study, a large population of MG patients was studied for evidence of peripheral blood T cell activation by several assays. Assays based on non-specific measurements of T cell activation as well as assays of antigen-specific clonal expansion were utilized. Levels of soluble IL-2 receptor in serum were modestly elevated in some patients, suggesting T cell activation. However, peripheral blood cells did not show evidence of IL-2 receptor expression or enhanced reactivity to IL-2 in culture. Clonable T cells selected for hypoxanthine phosphoribosyl transferase (hprt) mutation, another non-antigen-specific marker for T cell activation, were not seen with increased frequency except in patients treated with purine analogs. Antigen-specific T cell activation was measured by proliferation assays using heterologous and autologous sources of AChR. Antigen-restimulated peripheral blood cell cultures were cloned by limiting dilution. The vast majority of patients failed to show convincing evidence of AChR specific T cell activation or clonal expansion; only 2 of 44 patients demonstrated clonable autologous AChR-specific T cells. An alternative hypothesis of T cell involvement in MG is proposed in which T cell activation is discontinuous and predominantly directed at antigens other than AChR.

Adult↗
PubMed1996

Characterization of the APC gene in sporadic gastric adenocarcinomas.

The prominent role of the APC gene in colorectal tumor development is well established. However, its role in tumorigenesis in other tissues is not clear. Hence, DNA from 30 primary sporadic gastric adenocarcinomas was obtained from patients living in a high risk area of the world (North-Central Italy) in order to further define APC's role in gastric tumorigenesis. We thoroughly examined that region of APC which is commonly mutated in colorectal tumors using proven sensitive methods. The IVS protein assay and DNA sequence analysis of APC codons 686 through 1693 revealed no intragenic mutations. However, allelic loss of loci near APC was detected in 7 (28%) of 25 informative gastric adenocarcinomas using two 5q dinucleotide repeat markers for LOH analysis. These results suggest that genetic alteration of a region of APC commonly mutated in colorectal cancer is not a common event during sporadic gastric tumor development, at least in patients from North-Central Italy. Further analysis of chromosome 5q might identify another gene to be significantly altered in these gastric cancers.

Adenocarcinoma↗
PubMed1996

Cervical myelopathy with false localizing sensory levels.

BACKGROUND: The diagnosis of cervical myelopathy is not always initially recognized. Only a few reports have described the discrepancy between sensory level and the site of cord compression, but none, to our knowledge, have used magnetic resonance imaging (MRI) for localization. OBJECTIVE: To identify a syndrome of compressive cervical myelopathy with false localizing thoracic sensory levels. DESIGN: Case series. SETTING: A university hospital referral center. RESULTS: Four men, aged 24 to 60 years, presented with progressive weakness and hyperreflexia involving the lower extremities and distinct thoracic sensory levels ranging from T-4 to T-10. None of these patients had cervical pain, history of trauma, or upper extremity symptoms. Results of MRI scans of the thoracic spinal cord were unremarkable. Initially, 1 patient was suspected of having transverse myelitis and was treated with high-dose steroids. All 4 patients were eventually found to have cervical spinal cord compression, diagnosed by MRI. Three patients underwent surgery for decompression of the cervical lesion. While all 3 improved in lower extremity strength, 2 had persistent discrete thoracic sensory levels postoperatively. CONCLUSIONS: Failure to diagnose cervical myelopathy because of the presence of a thoracic sensory level can delay appropriate treatment or lead to incorrect therapy. Persistence of a thoracic sensory level following surgery can occur.

Adult↗
PubMed1996

Isolated vitamin E deficiency.

A 22-year-old man presented with progressive gait instability, tremor, and dysarthria since childhood. Electrophysiologic studies revealed a sensorimotor polyneuropathy. Laboratory studies documented vitamin E deficiency; however, no gastrointestinal, hepatic, or lipoprotein disorder could be identified. Vitamin E therapy normalized the serum level, but there was no neurologic improvement. Isolated vitamin E deficiency, in the absence of lipid malabsorption, should be considered in the evaluation of children and adults with ataxia and peripheral neuropathy.

Adult↗