PubMed Health⌕ Search

Biomedical subjects

C Pollitt

Publications and source records attributed to C Pollitt.

At least 19 recordsLinked to original sources
PubMed2000

Secondary reduction in calpain 3 expression in patients with limb girdle muscular dystrophy type 2B and Miyoshi myopathy (primary dysferlinopathies).

Dysferlin is the protein product of the gene (DYSF) that is defective in patients with limb girdle muscular dystrophy type 2B and Miyoshi myopathy. Calpain 3 is the muscle-specific member of the calcium activated neutral protease family and primary mutations in the CAPN3 gene cause limb girdle muscular dystrophy type 2A. The functions of both proteins remain speculative. Here we report a secondary reduction in calpain 3 expression in eight out of 16 patients with a primary dysferlinopathy and clinical features characteristic of limb girdle muscular dystrophy type 2B or Miyoshi myopathy. Previously CAPN3 analysis had been undertaken in three of these patients and two showed seemingly innocuous missense mutations, changing calpain 3 amino acids to those present in the sequences of calpains 1 and 2. These results suggest that there may be an association between dysferlin and calpain 3, and further analysis of both genes may elucidate a novel functional interaction. In addition, an association was found between prominent expression of smaller forms of the 80 kDa fragment of laminin alpha 2 chain (merosin) and dysferlin-deficiency.

Calpain↗
PubMed2000

Multicore myopathy: respiratory failure and paraspinal muscle contractures are important complications.

Three ambulant males with multicore myopathy, a rare congenital myopathy, are reported with nocturnal hypoventilation progressing to respiratory failure at the age of 9, 13, and 21 years. Deterioration in these individuals occurred over several months without any precipitating event. Patients had clinical evidence of nocturnal hypoventilation with hypoxaemia and hypercapnia. Forced vital capacity was significantly reduced (20 to 43% of predicted level). These parameters improved on institution of overnight ventilation using a BiPAP pressure support ventilator with face mask or nasal pillows with O2 saturation maintained above 90% overnight and an increase in forced vital capacity by as much as 100% (0.3 to 0.6 litres). This was matched by a symptomatic and functional improvement. Also present in these patients and not previously reported is the association of multicore myopathy with paraspinal contractures which produce a characteristic scoliosis described as a 'side-sliding' spine. This may be improved by spinal bracing or surgery.

Adolescent↗
PubMed2000

Dominant mutations in ROR2, encoding an orphan receptor tyrosine kinase, cause brachydactyly type B.

Inherited limb malformations provide a valuable resource for the identification of genes involved in limb development. Brachydactyly type B (BDB), an autosomal dominant disorder, is the most severe of the brachydactylies and characterized by terminal deficiency of the fingers and toes. In the typical form of BDB, the thumbs and big toes are spared, sometimes with broadening or partial duplication. The BDB1 locus was previously mapped to chromosome 9q22 within an interval of 7.5 cM (refs 9,10). Here we describe mutations in ROR2, which encodes the orphan receptor tyrosine kinase ROR2 (ref. 11), in three unrelated families with BDB1. We identified distinct heterozygous mutations (2 nonsense, 1 frameshift) within a 7-amino-acid segment of the 943-amino-acid protein, all of which predict truncation of the intracellular portion of the protein immediately after the tyrosine kinase domain. The localized nature of these mutations suggests that they confer a specific gain of function. We obtained further evidence for this by demonstrating that two patients heterozygous for 9q22 deletions including ROR2 do not exhibit BDB. Expression of the mouse mouse orthologue, Ror2, early in limb development indicates that BDB arises as a primary defect of skeletal patterning.

Amino Acid Sequence↗
PubMed2000

Clinical and molecular genetic spectrum of autosomal dominant Emery-Dreifuss muscular dystrophy due to mutations of the lamin A/C gene.

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by early contractures of the elbows and Achilles tendons, slowly progressive muscle wasting and weakness, and life-threatening cardiomyopathy with conduction blocks. We recently identified LMNA encoding two nuclear envelope proteins, lamins A and C, to be implicated in the autosomal dominant form of EDMD. Here, we report on the variability of the phenotype and spectrum of LMNA mutations in 53 autosomal dominant EDMD patients (36 members of 6 families and 17 sporadic cases). Twelve of the 53 patients showed cardiac involvement exclusively, although the remaining 41 all showed muscle weakness and contractures. We were able to identify a common phenotype among the patients with skeletal muscle involvement, consisting of humeroperoneal wasting and weakness, scapular winging, rigidity of the spine, and elbow and Achilles tendon contractures. The disease course was generally slow, but we observed either a milder phenotype characterized by late onset and a mild degree of weakness and contractures or a more severe phenotype with early presentation and a rapidly progressive course in a few cases. Mutation analysis identified 18 mutations in LMNA (i.e., 1 nonsense mutation, 2 deletions of a codon, and 15 missense mutations). All the mutations were distributed between exons 1 and 9 in the region of LMNA that is common to lamins A and C. LMNA mutations arose de novo in 76% of the cases; 2 of these de novo mutations were typical hot spots, and 2 others were identified in 2 unrelated cases. There was no clear correlation between the phenotype and type or localization of the mutations within the gene. Moreover, a marked inter- and intra-familial variability in the clinical expression of LMNA mutations exists, ranging from patients expressing the full clinical picture of EDMD to those characterized only by cardiac involvement, which points toward a significant role of possible modifier genes in the course of this disease. In conclusion, the high proportion of de novo mutations together with the large spectrum of both LMNA mutations and the expression of the disease should now prompt screening for LMNA in familial and sporadic cases of both EDMD and dilated cardiomyopathy associated with conduction system disease.

Adolescent↗
PubMed1999

Calpainopathy-a survey of mutations and polymorphisms.

Limb-girdle muscular dystrophy type 2A (LGMD2A) is an autosomal recessive disorder characterized mainly by symmetrical and selective atrophy of the proximal limb muscles. It derives from defects in the human CAPN3 gene, which encodes the skeletal muscle-specific member of the calpain family. This report represents a compilation of the mutations and variants identified so far in this gene. To date, 97 distinct pathogenic calpain 3 mutations have been identified (4 nonsense mutations, 32 deletions/insertions, 8 splice-site mutations, and 53 missense mutations), 56 of which have not been described previously, together with 12 polymorphisms and 5 nonclassified variants. The mutations are distributed along the entire length of the CAPN3 gene. Thus far, most mutations identified represent private variants, although particular mutations have been found more frequently. Knowledge of the mutation spectrum occurring in the CAPN3 gene may contribute significantly to structure/function and pathogenesis studies. It may also help in the design of efficient mutation-screening strategies for calpainopathies.

Amino Acid Sequence↗
PubMed1998

Non-tuberculous mycobacterial infection in children with cancer.

Reported here is the clinical presentation and management of patients with rapidly growing non-tuberculous mycobacterial infection diagnosed in a paediatric oncology unit. A retrospective analysis that correlated patient isolates with the children's cancer registry revealed two cases of non-tuberculous mycobacterial infection; both had been observed within the last 6 years and were due to Mycobacterium chelonae. The first case was line-associated and the second was a disseminated infection. In both cases the patients were lymphopenic and had had indwelling vascular catheters. Neither patient was neutropenic. The literature on mycobacterial infection in children with cancer is also reviewed.

Child, Preschool↗
PubMed1998

Muscle pain as a prominent feature of facioscapulohumeral muscular dystrophy (FSHD): four illustrative case reports.

Clinical studies of facioscapulohumeral muscular dystrophy (FSHD) rarely report muscle pain as a significant feature of the condition. We report four adult patients with FSHD in whom muscle pain was a presenting complaint and remains their most disabling symptom. These four patients were investigated using a pain questionnaire and diary. Inflammatory and metabolic causes of muscle pain were sought by muscle biopsy and a range of biochemical investigations. All patients reported between three and seven different pains of varying site and nature. None of the group had more than one painfree day per month and all complained of disturbed sleep. While some pains could potentially be attributed to postural problems, others were clearly myalgic in nature, though most often not specifically exercise-related. These myalgic pains could be particularly difficult to control. Results of metabolic investigations and muscle biopsy revealed no clue to the pathogenesis of these pains and there was no evidence for any exceptional inflammatory response. We believe that pain in FSHD is an under-reported but significant symptom and that further work is necessary to determine its prevalence, understand its cause and provide effective treatment.

Adult↗
PubMed1998

Abnormal merosin in adults. A new form of late onset muscular dystrophy not linked to chromosome 6q2.

We have identified seven patients (including two sib pairs) with a predominantly late onset limb-girdle muscular dystrophy in whom an absence of merosin was noted on immunoblotting. Merosin immunocytochemistry was normal, and no abnormalities were detected on immunostaining for the various proteins known to be involved in the limb-girdle muscular dystrophies (alpha, beta, gamma, delta sarcoglycan and calpain 3). Apart from one patient, where muscle problems began in childhood, reported age at onset of muscle weakness involving initially the proximal muscles of the lower limbs ranged from 17 to 40 years. The pattern of muscle involvement was similar from patient to patient, with hypertrophy of at least the calf muscles, absence of scapular winging and predominant involvement of hip flexors and adductors and hamstrings more than quadriceps. Serum creatine kinase in all patients was at least 10 times normal, and muscle biopsies showed non-specific dystrophic features. We believe that the patients described here may represent a genetically distinct subset within the limb-girdle muscular dystrophy group.

Adolescent↗
PubMed1993

The politics of medical quality: auditing doctors in the UK and the USA.

Following the 1989 white paper Working for Patients, medical audit has emerged as the principal officially-approved means of assuring the quality of NHS medical care. Beneath the surface consensus, however, significant arguments continue concerning both the purposes and the character of such audit. A 'medical model' of medical audit is in competition with a more managerial approach, while consumer interests, however unsuccessfully, are also trying to claim a role. Comparison with the system of peer review in the USA indicates that medical audit in the NHS is likely to be particularly weak with respect to public accountability. Nevertheless, when taken together with other features of the white paper's proposals, the universalization of medical audit offers managers an opportunity to begin to constrain the behaviour of hospital doctors at the local level.

Interprofessional Relations↗
PubMed1990

No hiding place: on the discomforts of researching the contemporary policy process.

It has never been easy to conduct research into currently sensitive policy issues, but there is now accumulating evidence to indicate that various forms of resistance to scholarly investigation are on the increase. Such a climate handicaps all social policy research, but may have the greatest impact on ethnographic projects. Yet, it is argued, ethnography is increasingly widely recognised among academics as having a particularly valuable contribution to make to the study of the policy process. Unfortunately, many policy practitioners (and occasionally some academic colleagues) perceive ethnographic research as being of questionable validity and low helpfulness. This behaves policy-oriented ethnographers to demonstrate that they do indeed have procedures for assuring validity, even if their style of investigation is never likely to be popular with government.

Ethnology↗
PubMed1989

Consuming passions.

Explore the source record for details and available documents.

Community Participation↗
PubMed1989

General management and medical autonomy in the National Health Service.

Clinical freedom is an elastic concept and its practical meaning to clinicians varies with time and context. Management pressure on clinical freedom is also likely to be elastic. Resource constraints are increasing pressure on clinical freedom. The paper reviews the nature of such pressure and considers the extent to which general managers have successfully eroded medical autonomy. Drawing on emerging evidence from research in progress on the impact of general management, the paper concludes that there is little sign of change in doctor-manager relations. They continue to inhabit a shared culture of medical autonomy in which only rarely do managers challenge clinicians.

Decision Making↗