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Biomedical subjects

M Burch

Publications and source records attributed to M Burch.

At least 19 recordsLinked to original sources
PubMed2006

Heart and heart-lung transplantation for idiopathic restrictive cardiomyopathy in children.

OBJECTIVE: To review the outcome of cardiac transplantation for restrictive cardiomyopathy (RCM) in children and to assess the ability of new strategies to modulate the effects of high pulmonary vascular resistance. DESIGN: Retrospective case note analysis of all patients receiving a transplant for RCM. PATIENTS: 18 children with RCM referred for transplantation assessment to Great Ormond Street Hospital, London. RESULTS: Eight boys and 10 girls were referred for assessment. Median age at presentation was 5.0 (mean (SD) 6.1 (4.0)) years. Fourteen orthotopic and two heterotopic transplantations were performed and two patients were referred for heart-lung transplantation. Mean duration from diagnosis to transplantation was 3.3 (3.0) years. Three patients with haemodynamic decompensation before transplantation had increased morbidity in the postoperative period. No patients died while awaiting a transplant. Three patients died in the first year after transplantation, one within 30 days. Five patients received pre-transplantation prostacyclin for a mean duration of 57 (18) days. Transpulmonary gradient was reduced in four of the patients. Mean transpulmonary gradient was 27 (9.8) mm Hg before and 17 (6.7) mm Hg after treatment with prostacyclin (p < 0.05). CONCLUSION: Most children with RCM require transplantation within four years of diagnosis. Referral for transplantation assessment should precede haemodynamic decompensation. Increase of pulmonary vascular resistance is a variable problem but can be modulated with pre-transplantation prostacyclin. With these strategies, orthotopic transplantation is possible in the majority of cases.

Adolescent↗
PubMed2004

Enterovirus myocarditis as a cause of neonatal collapse.

Seven neonates required intensive care at our institution with enterovirus myocarditis, 2001-2003. Presentation was at a median age of 9 days. All had ischaemic electrocardiograms, poor ventricular function, raised creatine kinase, and enterovirus RNA detected by reverse transcriptase polymerase chain reaction. Four survived. Enterovirus myocarditis may be an under recognised cause of neonatal collapse.

Electrocardiography↗
PubMed2004

Persistent pulmonary hypertension late after neonatal aortic valvotomy: a consequence of an expanded surgical cohort.

BACKGROUND: Survival of neonates with critical aortic stenosis has improved over the past decade. Models based on morphological characteristics have been designed to help determine whether early survival is more likely after biventricular repair (surgical or balloon aortic valvotomy) or after a single ventricle staged palliative surgical strategy. However, late follow up data are lacking. OBJECTIVE: To report follow up data on survivors of neonatal aortic valvotomy who had persistent pulmonary hypertension caused by restriction to left ventricular filling. RESULTS: Of four medium term survivors of neonatal valvotomy for critical aortic stenosis who had persistent pulmonary hypertension, one died aged 4 years and the other three have severe limitation of effort tolerance. CONCLUSIONS: This previously unreported late complication of "successful" biventricular repair for neonatal critical aortic stenosis is an important consideration in determining the initial management.

Aortic Valve Stenosis↗
PubMed2002

Effects of meteorological conditions on spore plumes.

Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard spore traps at several sampling stations. This study involved the examination of the hourly spore concentrations on days that had average daily concentrations near 50,000 spores/m(3) or greater. Hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined on 4 days at three sites and then correlated with hourly meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. On each of these days there was a spore plume, a phenomenon in which spore concentrations increased dramatically over a very short period of time. Spore plumes generally occurred near midday, and concentrations were seen to increase from lows around 20,000 total spores/m(3) to highs over 170,000 total spores/m(3) in 2 h. Multiple regression analysis of the data indicated that increases in temperature, dew point, and air pressure correlated with the increase in spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as on 3 of the 4 days when spore plumes occurred there were thunderstorms later that evening. The occurrence of spore plumes may have clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.

Air Microbiology↗
PubMed2002

Prenatal diagnosis of coarctation of the aorta improves survival and reduces morbidity.

OBJECTIVE: To investigate whether antenatal diagnosis of coarctation of the aorta results in reduced mortality and improved preoperative haemodynamic stability compared with postnatal diagnosis. DESIGN: Retrospective review of all cases of coarctation of the aorta presenting to a tertiary fetal and neonatal cardiology service from January 1994 to December 1998. METHODS: Prenatal, postnatal, and necropsy records were reviewed to determine survival in the two groups. Markers of preoperative illness severity were recorded, including presence of femoral pulse, collapse, left ventricular function, ductal patency on echocardiography, coagulation status, duration of intensive care unit and total hospital stay, heart rate, respiratory rate, plasma creatinine, plasma potassium, and right upper limb blood pressure. A univarate and multivariate analysis was conducted on all variables and a cumulative score was created and subjected to logistic regression analysis. RESULTS: Both collapse and death were more common in the postnatally diagnosed group (p < 0.05). Femoral pulses were more likely to be palpable and there was echocardiographic evidence of duct patency in the antenatally diagnosed infants (p < 0.001 and p < 0.05, respectively). An increased respiratory rate was associated with postnatal presentation (p < 0.05). Infants with haemodynamic instability preoperatively were more likely to have been diagnosed postnatally (p < 0.01). CONCLUSIONS: Antenatal diagnosis of coarctation of the aorta is associated with improved survival and preoperative clinical condition.

Adolescent↗
PubMed2001

Cardiac abnormalities and skeletal muscle weakness in carriers of Duchenne and Becker muscular dystrophies and controls.

Cardiac abnormalities, cardiomyopathy and skeletal muscle weakness have been described in female carriers of the Xp21 (Duchenne and Becker) muscular dystrophies (J Neurol 1975;209(4):279-285; Br Med J 1969;2:418-420; J AmMed Assoc 1996;275(17):1335-1338; Neurology 1980;30(5):497-501; Neuromusc Disord 1999;9:347-351; Arch Neurol 1989;46:673-675). We have screened volunteers from our Xp21 genetics register and found the prevalence of previously unrecognized, clinically relevant, abnormalities in this group to be less than previously reported. We studied 91 women (56 carriers and 35 controls), aged between 18 and 69 years, from our local population known to the Oxford Regional Genetics Register. Our study included controls, with the investigators being blind to the subject's genetic status. The prevalence of previously unrecognised cardiac abnormalities on echocardiogram and ECG was 18% (10/56). Seven percent (4/56) of carriers had cardiomyopathy, defined by significant LV dilatation and decreased shortening fraction. In most cases, subjects with abnormal cardiac findings were asymptomatic. Echocardiography was more frequently abnormal than electrocardiography, but in many subjects the measurements of left ventricular dimensions were only just outside the normal ranges. The prevalence of skeletal muscle weakness was 12% (7/56). It was usually recognized by the individual, although not previously volunteered, but was mild and did not substantially affect activities of daily living.

Adult↗
PubMed2001

Nodularin uptake by seafood during a cyanobacterial bloom.

The problem of blue-green algal toxin contamination of recreational waters and drinking water catchments is well described, as is the potential contamination of associated seafood. Algal contamination of Victorian waterways is now a widespread annual occurrence and, in some regions, the intersection of blooms and commercial fishing threatens the food safety of large numbers of people. Toxin levels which produce no observed adverse effect in animal studies were used to derive safe tolerable daily intake levels. These 'acceptable levels' were then modified to protect against potential acute health risks associated with short-term exposures. National food surveys were used to derive likely seafood intakes and thus, in combination with 'safe toxin levels', health alert levels for seafood were formulated. During the summer of 2001 a bloom of Nodularia spumigena occurred in the Gippsland Lakes area of Southern Victoria. During the bloom, seafood samples were collected and nodularin concentrations were estimated. Nodularin concentrations reached levels of concern in mussels and in prawn viscera at cell counts as low as 30,000 cells/ml. Nodularin concentrations in the flesh of finfish remained low. Boiling the seafood redistributed toxin between viscera and flesh. The results were used to restrict some seafood harvesting.

Animals↗
PubMed1997

Comparison of the functional significance of left ventricular hypertrophy in hypertrophic cardiomyopathy and glycogenosis type III.

A comparison of blood pressure response with exercise stress, thallium scintigraphy, and 24-hour electrocardiographic monitoring between 5 patients with left ventricular hypertrophy associated with glycogen storage disease type III and 10 matched patients with hypertrophic cardiomyopathy revealed normal results in the former group. These data highlight the importance of the etiology of left ventricular hypertrophy before the application of risk stratification.

Adolescent↗
PubMed1997

Ruptured left ventricular diverticulum in infancy.

Congenital diverticulum of the left ventricle is rare, and rupture of such a diverticulum is even more rare. We describe successful surgical repair of a ruptured left ventricular diverticulum in an 11-month-old infant.

Cardiac Tamponade↗
PubMed1997

Elastin: genomic structure and point mutations in patients with supravalvular aortic stenosis.

We describe the complete exon-intron structure of the human elastin (ELN) gene located at chromosome 7q11.23. There are 34 exons occupying approximately 47 kb of genomic DNA. All exons are in-frame, allowing exon skipping without disrupting the reading frame. Microsatellites are located in introns 17 and 18. Deletions of all or large parts of the ELN gene have been previously reported in two patients with supravalvular aortic stenosis (SVAS), and SVAS is also a frequent feature of Williams syndrome, where patients are hemizygous for ELN. We list primer pairs for amplifying each exon, with flanking intron, from genomic DNA to allow detection of point mutations in the ELN gene. We show that some patients with isolated SVAS have point mutations that are predicted to lead to premature chain termination. Knowledge of the genomic structure will allow more extensive mutation screening in genomic DNA of patients with SVAS and other conditions.

Amino Acid Sequence↗
PubMed1996

Fatal cardiomyopathy in dystrophic epidermolysis bullosa.

Two unrelated children with autosomal recessive dystrophic epidermolysis bullosa (RDEB) developed fatal dilated cardiomyopathy. Both were malnourished and had severe growth problems. We believe that the most likely cause for the cardiomyopathy is a micronutrient deficiency, most probably selenium deficiency, since the serum selenium level was found to be reduced in the case in whom we measured this, and in 14 of 25 other children with dystrophic epidermolysis bullosa. Echocardiographic screening of 18 other patients revealed no evidence of cardiomyopathy. We recommend careful attention to nutrition, with prospective monitoring of vitamins and micronutrients including selenium and carnitine, and regular echocardiographic screening of patients with severe RDEB.

Adolescent↗
PubMed1995

Repair of anomalous pulmonary venous connection to the superior vena cava.

Complex forms of anomalous pulmonary venous connection to the superior vena cava (SVC) can be difficult to correct surgically. Since 1987, 11 patients have undergone repair of anomalous pulmonary venous connection to the SVC by diversion of the pulmonary venous drainage to the left atrium using a baffle with division of the SVC and reimplantation on the right atrial appendage to restore normal systemic venous drainage. Total anomalous pulmonary venous connection was present in 3 patients and partial anomalous pulmonary venous connection, in 8. All patients are alive and asymptomatic at a mean follow-up of 2.3 +/- 1.4 years. Postoperative echo-cardiograms (8 patients) revealed pulmonary venous obstruction requiring reoperation in 1 patient. No patient has clinical evidence of SVC obstruction, and all are in sinus rhythm. This is a safe and effective technique for repair of complex forms of anomalous pulmonary venous connection to the SVC, and the incidence of postoperative venous obstruction and rhythm disturbances is low.

Adolescent↗