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Biomedical subjects

M Burch

Publications and source records attributed to M Burch.

52 records · Page 3Linked to original sources
PubMed1990

Plasma atrial natriuretic peptide after the Fontan procedure and total cavopulmonary connexion.

Plasma atrial natriuretic peptide was measured in 10 children undergoing the Fontan procedure and 3 children undergoing total cavopulmonary connexion. There was no significant difference in pre-operative plasma levels, but post-operative levels were significantly higher 48 hours after cardiopulmonary bypass in the Fontan group. There was no significant difference in plasma arginine vasopressin levels either pre- or post-operatively. Post-operative pleural effusions occurred in only 2 of the 10 patients undergoing the Fontan procedure, but were present in all 3 of those undergoing total cavopulmonary connexion. The release of atrial natriuretic peptide is an appropriate homeostatic response to volume loading and the impairment of this response in the early post-operative period may be of clinical importance.

Arginine Vasopressin↗
PubMed1990

Open valvotomy for critical aortic stenosis in infancy.

Over a 5 year period open valvotomy was performed on 13 patients under the age of one year with critical aortic stenosis. All 13 survived operation. There were two late deaths--one 38 days after operation, associated with an unrelated neurosurgical procedure and the other 2 years 6 months after when aortic root enlargement and replacement of the aortic valve were performed. During this period two other infants presented with aortic stenosis. One, who was very ill before transfer, died before operation could be performed. The second patient had a hypoplastic left ventricle with a small mitral valve ring and was, therefore, considered to be part of a different subgroup. All the surviving children have been followed up (median length of follow up 2 years and 11 months, range 7 months-5 years). Left ventricular function, in terms of percentage systolic wall thickening, was shown to be significantly impaired in all age groups. Peak diastolic thinning was abnormal in those children aged from 3 to 5. The aortic valve gradient, as assessed by peak instantaneous continuous wave Doppler, was less than 40 mm Hg in five patients and between 40 and 70 mm Hg in seven patients. One patient, with appreciable restenosis, has undergone successful percutaneous balloon dilatation of the aortic valve.

Aortic Valve↗
PubMed1990

Plasma concentration of atrial natriuretic peptide in spontaneous atrioventricular re-entrant tachycardias of childhood.

Plasma atrial natriuretic peptide was measured in 13 children between the ages of 1 week and 2 years 9 months during atrioventricular re-entrant tachycardia and 15 minutes after the restoration of sinus rhythm. There was a significant decline in atrial natriuretic peptide during sinus rhythm. Plasma concentrations of the peptide were significantly higher during tachycardia in seven infants under 1 year than in the six older children. The heart rates and the duration of tachycardia were not significantly different in the two age groups. Cardiac failure was present in five of seven children under 18 weeks of age during tachycardia but in none of the older children. The plasma concentration of atrial natriuretic peptide did not significantly correlate with duration of tachycardia or heart rate. If tachycardia occurs in young infants the low functional reserve capacity of the developing heart leads to cardiac failure more frequently and it is likely that this was the cause of the significantly higher plasma concentration of atrial natriuretic peptide in the younger children.

Adenosine↗
PubMed1986

Multiple sulphatase deficiency presenting at birth.

A new case of multiple sulphatase deficiency with onset at birth is described. The patient had many dysmorphic features and hydrocephalus, similar to one other case with early onset described in the literature. The new patient differed from the other case in having chondrocalcificans congenita, heart abnormalities and an abnormal fold of tissue present between the laryngeal inlet and the oesophagus. Excessive mucopolysacchariduria was present and there was profound deficiency of all sulphatases examined in plasma, leucocytes and cultured skin fibroblasts.

Abnormalities, Multiple↗
PubMed1985

Structure-activity relationships for the irreversible blockade of nicotinic receptor agonist sites by lophotoxin and congeneric diterpene lactones.

Lophotoxin, a diterpene lactone paralytic toxin from gorgonian corals of the genus Lophogorgia, inhibits [125I]-alpha-toxin binding to surface nicotinic receptors of BC3H-1 cells by irreversible occupation of the primary agonist sites. In contrast, receptor-bearing membrane fragments or detergent-solubilized receptors prepared from BC3H-1 cells are not susceptible to lophotoxin block. Thus, lophotoxin inhibition requires intact cells. However, when intact cells were incubated with lophotoxin, subsequent membrane-fragment preparation or detergent solubilization of the receptors did not diminish lophotoxin occupation of [125I]-alpha-toxin-binding sites, indicating that lophotoxin binds very tightly to nicotinic receptors. These studies further demonstrate that both surface and nonsurface nicotinic receptors of BC3H-1 cells are susceptible to irreversible occupation by lophotoxin, indicating that the lipophilic toxin freely permeates intact cells. We also examined several structural analogs of lophotoxin, one of which was equipotent with lophotoxin for inhibition of [125I]-alpha-toxin binding to intact cells and, notably, also blocked alpha-toxin binding to detergent-extracted receptor. Furthermore, this active analog inhibited [125I]-alpha-toxin binding to receptor-rich membrane fragments prepared from Torpedo electric organ, a preparation in which lophotoxin was inactive. Structure-activity relationships exhibited by the lophotoxin congeners suggest mechanisms for covalent bonding to the receptor by way of a Michael addition or by Schiff base formation.

Animals↗
PubMedDate not supplied

Unexpected oxygen desaturation after cardiopulmonary bypass: rapid confirmation of unroofing of the coronary sinus by intraoperative epicardial echocardiography.

Unexpected arterial oxygen desaturation occurred immediately after cardiopulmonary bypass in two children. Epicardial echocardiography demonstrated unroofing of the coronary sinus after a Fontan procedure in the first child and rapidly excluded this abnormality in the second, who had undergone closure of a sinus venosus defect and in whom there was also a left superior vena cava draining to the coronary sinus. Epicardial echocardiography determined management in both patients: Oversewing of the ostium of the coronary sinus was undertaken in the first case during an additional period of cardiopulmonary bypass. Oxygen saturation values improved with aggressive endotracheal lavage and aspiration of secretions in the second child. Epicardial echocardiography can identify unroofing of the coronary sinus (which may be difficult to diagnose by transesophageal echocardiography) and can identify or exclude this condition when unexpected arterial oxygen desaturation is present after cardiac surgery.

Cardiopulmonary Bypass↗
PubMedDate not supplied

The inheritance of hypertrophic cardiomyopathy.

The inheritance of hypertrophic cardiomyopathy is autosomal dominant, "sporadic" cases are now recognised to be uncommon. In the past 5 years molecular genetic advances have isolated >100 different mutations in genes encoding sarcomeric proteins. The cardiac morphology and prognosis are linked to the underlying genetic defect, but intra and interfamilial variation suggest polymorphism or mutation of other genes, or environmental factors. Penetrance is age related and negative echocardiographic screening cannot guarantee absence of disease. Currently mutation analysis is not routine in clinical practice.

Age Distribution↗
PubMedDate not supplied

Acute sternal opening after cardiac surgery in children: effect on plasma atrial natriuretic peptide.

Plasma atrial natriuretic peptide (ANP) was measured immediately before and 15 minutes after re-opening of the sternotomy and delayed sternal closure were performed to alleviate possible myocardial compression in 3 children. As acute re-opening of the sternotomy is a rare occurrence our sample size was necessarily small. ANP increased following the procedure in all 3 patients, and this was significant (p less than 0.02) when compared to plasma levels obtained from 9 children who underwent sternotomy prior to elective cardiac surgery. Following acute re-opening of the sternotomy there was an increase in median urine output and a decrease in median central venous pressure. Our results illustrate that it is atrial wall stress rather than intra-atrial pressure that determines release of ANP, and in addition suggest ANP may be a factor in the rapid clinical improvement following delayed sternal closure for atypical tamponade in children.

Atrial Natriuretic Factor↗