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Biomedical subjects

J Burn

Publications and source records attributed to J Burn.

At least 19 recordsLinked to original sources
PubMed1992

Atrial fibrillation and stroke: prevalence in different types of stroke and influence on early and long term prognosis (Oxfordshire community stroke project)

OBJECTIVE: To determine in patients with first ever stroke whether atrial fibrillation influences clinical features, the need to perform computed tomography, and prognosis. DESIGN: Observational cohort study with maximum follow up of 6.5 years. SETTING: Primary care, based on 10 general practices in urban and rural Oxfordshire. SUBJECTS: Consecutive series of 675 patients with first ever stroke registered in the Oxfordshire community stroke project. MAIN OUTCOME MEASURES: Prevalence of atrial fibrillation by type of stroke; effect of atrial fibrillation on case fatality rate and risk of recurrent stroke, vascular death, and death from all causes. RESULTS: Prevalence of atrial fibrillation was 17% (95% confidence interval 14% to 20%) for all stroke types (115/675), 18% (15% to 21%) for cerebral infarction (97/545), 11% (4% to 11%) for primary intercerebral haemorrhage (7/66), and 0% (0 to 11%) for subarachnoid haemorrhage (0/33). For patients with cerebral infarction the 30 day case fatality rate was significantly higher with atrial fibrillation (23%) than with sinus rhythm (8%); the risk of early recurrent stroke (within 30 days) was 1% with atrial fibrillation and 4% with sinus rhythm. In patients who survived at least 30 days the average annual risk of recurrent stroke was 8.2% (5.9% to 10.9%) with sinus rhythm and 11% (6.0% to 17.3%) with atrial fibrillation. CONCLUSIONS: After a first stroke atrial fibrillation was not associated with a definite excess risk of recurrent stroke, either within 30 days or within the first few years. Survivors with and without atrial fibrillation had a clinically important absolute risk of further serious vascular events.

Aged↗
PubMed1992

Deletions within chromosome 22q11 in familial congenital heart disease.

Because a locus on chromosome 22q11 is deleted in most individuals with DiGeorge and Shprintzen syndromes--conditions in which heart abnormalities are an important feature--we have looked for deletions in nine families with recurrent outflow-tract heart defects. In five families, chromosome 22 deletions were detected in all the living affected individuals studied and also in the clinically normal father of three affected children. The deletion was transmitted from parents to offspring and was associated with an increase in the severity of cardiac defects. No deletions were found in four families in which the parents were normal and affected siblings had anatomically identical defects. We propose that deletions within band q11 of chromosome 22 are an important cause of familial heart defects.

Autoradiography↗
PubMed1992

Velo-cardio-facial syndrome associated with chromosome 22 deletions encompassing the DiGeorge locus.

The large clinical overlap between DiGeorge syndrome and velo-cardio-facial syndrome suggests an aetiological connection. DiGeorge syndrome is associated with microdeletions of chromosome 22q11 and is therefore likely to be caused by reduced dosage of genes within this region. We present preliminary data that velocardiofacial syndrome patients have similar chromosome deletions, a finding consistent with the hypothesis that these disorders represent part of a spectrum of abnormalities seen with monosomy for 22q11.

Abnormalities, Multiple↗
PubMed1992

Interstitial deletions in DiGeorge syndrome detected with microclones from 22q11.

DiGeorge syndrome in humans is characterized by immunodeficiency, heart defects, mental retardation and facial dysmorphism; cytogenetic analysis has shown that deletions at 22q11 occur in approximately 25% of cases. To generate DNA markers from this region, we have microdissected and microcloned band q11 of human Chromosome (Chr) 22. Nineteen thousand clones were obtained from material dissected from 20 chromosome fragments. Seventeen of 61 clones analyzed (28%) were repetitive, 27 (44%) gave no signal, and 17 (28%) detected single copy sequences of which ten mapped to Chr 22. Two of these were found to be deleted in patients with DiGeorge syndrome and either monosomy for 22q11-pter or visible interstitial deletions of 22q11. These two markers are also hemizygous in patients with no visible chromosomal abnormality, demonstrating that submicroscopic deletions are common in DiGeorge syndrome patients.

Blotting, Southern↗
PubMed1992

Hereditary haemorrhagic telangiectasia: a clinical analysis.

Data from 98 patients with hereditary haemorrhagic telangiectasia (HHT) are presented. All were symptomatic by 40 years of age and 62% by 16 years. Nose bleeding was the first symptom of disease in 90% of cases with mucocutaneous telangiectases appearing 5 to 20 years later. Complications of HHT are discussed and an age of onset curve given.

Adolescent↗
PubMed1992

Adult-onset motor neuron disease and infantile Werdnig-Hoffmann disease (spinal muscular atrophy type 1) in the same family.

We describe a family in which infantile Werdnig-Hoffmann disease and adult-onset progressive muscular atrophy both occurred. The possibility of these two diseases developing within the same family by chance is unlikely, and several genetic hypotheses may be put forward to explain the association. We suggest that the molecular pathogenesis of these two subtypes of lower motor neuron degeneration may be linked. The genetic defect in the childhood spinal muscular atrophies has been mapped to chromosome 5q in close proximity to the microtubule-associated protein 1B locus. The association of diseases within this family suggests that chromosome 5q should also be studied in relation to adult-onset familial motor neuron disease.

Aged↗
PubMed1992

New dysmorphic syndrome with choanal atresia in siblings.

We report five children from three families who presented with bilateral choanal atresia associated with a spectrum of additional malformations including cardiac defects, deafness, defects of the external ear, eyes and eye lids and a characteristic dysmorphic appearance. The children were of normal intelligence. This syndrome is distinct from CHARGE association.

Abnormalities, Multiple↗
PubMed1992

A prospective cytogenetic study of 36 cases of DiGeorge syndrome.

Cytogenetic analysis was carried out in a prospective series of 36 children with DiGeorge syndrome. High-resolution banding (> 850 bands/haploid set) was achieved in 30 cases. Monosomy 22q11.21-->q11.23 was found in 9 of these 30 cases. In each of these cases monosomy 22q11.21-->q11.23 resulted from an interstitial deletion and not from a translocation. No other chromosome abnormalities were seen.

Child↗
PubMed1992

Molecular genetic study of the frequency of monosomy 22q11 in DiGeorge syndrome.

It is well established that DiGeorge syndrome (DGS) may be associated with monosomy of 22q11-pter. More recently, DNA probes have been used to detect hemizygosity for this region in patients with no visible karyotypic abnormality. However, DGS has also been described in cases where the cytogenetic abnormality does not involve 22q11; for instance, four cases of 10p- have been reported. In this study we have prospectively analyzed patients, by using DNA markers from 22q11, to assess the frequency of 22q11 rearrangements in DGS. Twenty-one of 22 cases had demonstrable hemizygosity for 22q11. Cytogenetic analysis had identified interstitial deletion in 6 of 16 cases tested; in 6 other cases no karyotype was available. When these results are combined with those from our previous studies, 33 of 35 DGS patients had chromosome 22q11 deletions detectable by DNA probes.

Chromosome Deletion↗
PubMed1992

Carrier testing for cystic fibrosis: knowledge and attitudes within a local community.

We report a questionnaire survey of 216 adults (aged 16-68) attending the dental hospital in Newcastle. This was undertaken to provide a representative assessment of the level of knowledge in the community of cystic fibrosis and attitudes towards testing for carrier status. Knowledge of inheritance and symptomatology of the condition was scored and found to be less than previously reported in selected population groups. In the majority the source of information reported was the mass media; only 27 respondents had any contact with an affected individual. The questionnaire provided information about the inheritance and effects of cystic fibrosis. Three-quarters of the respondents accepted the idea of carrier testing for themselves, which included most of those of reproductive age, and all considered that testing should be available to those planning a family. General practice surgeries were the most favoured venue for testing. The implications of these findings for those involved in the planning of population screening programmes are considered.

Adolescent↗
PubMed1992

A submicroscopic translocation, t(4;10), responsible for recurrent Wolf-Hirschhorn syndrome identified by allele loss and fluorescent in situ hybridisation.

A 2 year old girl presented with developmental delay and subtle dysmorphic features suggestive of Wolf-Hirschhorn syndrome (WHS). High resolution chromosome analysis was normal in the child and both parents. Molecular analysis indicated that the child had not inherited a maternal allele of probes from 4p16, confirming the clinical diagnosis. Prenatal diagnosis in the next pregnancy showed that again the fetus had no maternal allele for probes mapping to 4p16. Fluorescent in situ hybridisation in the mother showed a submicroscopic translocation, t(4;10). A normal karyotype in a child with clinical features of WHS is an indication for further investigation.

Abnormalities, Multiple↗
PubMed1992

Meiotic and sperm chromosome analysis in a male carrier of an inverted insertion (3;10)(q13.2;p14p13).

A phenotypically normal male who fathered a son with the karyotype 46,XY,del(10)(p13) was found to be a balanced carrier of an inverted insertion (3;10) (q13.2;p14p13). Karyotyping five later pregnancies showed four to be unbalanced with respect to the insertion, one of which was also trisomic for chromosome 18. The latest pregnancy was balanced with respect to insertion but had the additional complexity of 47,XXY. In the light of six out of six chromosomally abnormal pregnancies, two of which potentially exhibit an interchromosomal effect, it was decided to investigate the gametic output of the father. Testicular biopsy and semen samples were obtained permitting both meiotic and sperm chromosome analysis. Information was thus obtained at three levels of gamete production, that is, prophase I pairing, chiasma frequency distribution at metaphase I, and sperm karyotypes. Electron microscope studies of synaptonemal complexes showed the rearranged chromosomes to pair fully in meiotic prophase I with no indication of the presence of an insertion. This non-homologous pairing of the inserted region was accompanied by an abnormal frequency distribution of pachytene substages. There was also a reduction in chiasma frequency throughout the genome. However, this did not lead to detectable autosomal univalence or abnormally high X/Y univalence. Thus, the trisomy 18 and XXY pregnancies are unlikely to reflect increased non-disjunctional rates either before or during the first meiotic division. Sperm karyotyping showed that the proportion of chromosomally balanced:unbalanced gametes did not differ from the theoretically expected 1:1. There was no evidence of any increase of unrelated abnormalities in the sperm, further indicating that the overall rate of meiotic non-disjunction was not increased above normal.

Adult↗
PubMed1991

Classification and natural history of clinically identifiable subtypes of cerebral infarction.

We describe the incidence and natural history of four clinically identifiable subgroups of cerebral infarction in a community-based study of 675 patients with first-ever stroke. Of 543 patients with a cerebral infarct, 92 (17%) had large anterior circulation infarcts with both cortical and subcortical involvement (total anterior circulation infarcts, TACI); 185 (34%) had more restricted and predominantly cortical infarcts (partial anterior circulation infarcts, PACI); 129 (24%) had infarcts clearly associated with the vertebrobasilar arterial territory (posterior circulation infarcts, POCI); and 137 (25%) had infarcts confined to the territory of the deep perforating arteries (lacunar infarcts, LACI). There were striking differences in natural history between the groups. The TACI group had a negligible chance of good functional outcome and mortality was high. More than twice as many deaths were due to the complications of immobility than to direct neurological sequelae of the infarct. Patients in the PACI group were much more likely to have an early recurrent stroke than were patients in other groups. Those in the POCI group were at greater risk of a recurrent stroke later in the first year after the index event but had the best chance of a good functional outcome. Despite the small anatomical size of the infarcts in the LACI group, many patients remained substantially handicapped. The findings have important implications for the planning of stroke treatment trials and suggest that various therapies could be directed specifically at the subgroups.

Age Factors↗
PubMed1991

Disturbance of morphological laterality in humans.

Complete situs inversus is well described in humans and may be associated with defective cilia in Kartagener's syndrome, an autosomal recessive trait. Only half of homozygotes display situs inversus, presumably due to 'chance'. Isomerism sequence or Ivemark syndrome involves major disturbances of organ formation, the patterns of which suggest such individuals have either two right sides or two left sides to the body. Defects in an autosomal and more rarely in an X-linked gene are involved, though again chance factors probably influence expression. Isomerism may occur in one of monozygotic twins, particularly in the right half of conjoined twins. It is likely that the twinning process disturbs laterality in one of the pair. This provides one mechanism to explain the marked excess of heart defects in monozygotic twins. Most of these defects are not, however, associated with overt disturbances of laterality. Since the heart is the organ most sensitive to disturbed situs, one explanation is that the excess reflects a lesser degree of disturbed laterality. This would require a model where there is a gradation from normal situs through isomerism to situs inversus.

Bronchi↗
PubMed1991

Role of a regional register for familial adenomatous polyposis: experience in the northern region.

Within 36 months of its formation the Northern Region Polyposis Registry had increased the number of identified gene carriers of familial adenomatous polyposis from 56 to 65 in a population of 3.1 million and had achieved a 15-fold increase in the number of at-risk relatives being regularly screened. Review of the surgical records at the outset of the registry revealed that the mean age at diagnosis of those patients detected by screening was 24.7 years, whereas it was 36.6 years for those detected by symptoms. Ten of the 31 in the latter group had colorectal carcinomas whilst only one of those detected by screening had a cancer and a significantly higher proportion had sphincter-saving surgery. A regional registry can provide an effective screening and counselling service to surgeons treating patients with familial adenomatous polyposis. At-risk relatives are best assessed by combining results of the different screening procedures now available but the prime requirement of a successful registry is dedicated domiciliary counselling.

Adenomatous Polyposis Coli↗