Biomedical subjects

Murray Robertson

Publications and source records attributed to Murray Robertson.

4 recordsLinked to original sources

PubMed2006

Cardiac hypertrophy in anion exchanger 1-null mutant mice with severe hemolytic anemia.

Anion exchanger 1 (AE1; SLC4A1), the plasma membrane Cl(-)/HCO(3)(-) exchanger of erythrocytes, is also expressed in heart. The aim of this study was to assess the role of AE1 in heart function through study of AE1-null (AE1(-/-)) mice, which manifest severe hemolytic anemia resulting from erythrocyte fragility. Heart weight-to-body weight ratios were significantly higher in the AE1(-/-) mice than in wild-type (AE1(+/+)) littermates at both 1-3 days postnatal (3.01 +/- 0.38 vs. 1.45 +/- 0.04) and at 7 days postnatal (9.45 +/- 0.53 vs. 4.13 +/- 0.41), indicating that loss of AE1 led to cardiac hypertrophy. Heterozygous (AE1(+/-)) mice had no signs of cardiac hypertrophy. Morphology of the adult AE1(-/-) mutant heart revealed an increased left ventricular mass, accompanied by increased collagen deposition and fibrosis. M-mode echocardiography revealed dysfunction of the AE1(-/-) hearts, including dilated left ventricle end diastole and systole and expanded left ventricular mass compared with AE1(+/+) hearts. Expression of intracellular pH-regulatory mechanisms in the hypertrophic myocardium of neonate AE1(-/-) mutant mice was indistinguishable from AE1(+/-) and AE1(+/+) mice, as assessed by quantitative real-time RT-PCR. Confocal immunofluorescence revealed that, in normal mouse myocardium, AE1 is sarcolemmal, whereas AE3 and slc26a6 are found both at the sarcolemma and in internal membranes (T tubules and sarcoplasmic reticulum). These results indicate that AE1(-/-) mice, which suffer from severe hemolytic anemia and spherocytosis, display cardiac hypertrophy and impaired cardiac function, reminiscent of findings in patients with hereditary abnormalities of red blood cells. No essential role for AE1 in heart function was found.

Anemia, Hemolytic↗

PubMed2006

Antenatal diagnosis and successful surgical removal of a large right ventricular fibroma.

Congenital cardiac tumors are very rare and fibromas are the second most common type. Fibromas are benign tumors, but they have potentially serious complications. Their antenatal diagnosis is infrequently reported in the literature, and the management of these tumors is a source of controversy. We report the case of a rare form of right ventricular free wall fibroma. Antenatal diagnosis was made at 36 weeks of gestation, with subsequent successful resection at 2 weeks of age. A brief review of the literature focuses on the diagnostic approach and the clinical and surgical management of congenital cardiac fibromas.

Cardiac Surgical Procedures↗

PubMed2005

Pediatric poststernotomy mediastinitis.

BACKGROUND: Mediastinitis results in significant morbidity in pediatric cardiac patients. It is not clear whether delayed sternal closure is a risk factor for these infections. Management of mediastinitis remains controversial. METHODS: Cases of mediastinitis at the Stollery Children's Hospital from January 1, 1991, to June 30, 2004, were reviewed. RESULTS: There were 29 cases of mediastinitis in 2,675 open cardiac procedures for an overall incidence of 1.1%. Infection was diagnosed 5 to 27 days after the original surgical procedure (median, 10 days). The odds ratio for infection with delayed sternal closure versus primary sternal closure was 1.88 (95% confidence interval, 0.63 to 5.60). Signs at the onset of infection included fever (86%), incisional erythema (69%), purulent drainage from the incision or pacer wire sites (83%), and wound dehiscence (23%). Debridement was followed by primary sternal closure in all but three cases in which the sternum had not been closed before debridement and rotational muscle flaps were not used. Continuous irrigation systems were used only in the first 7 patients. One patient died of mediastinitis complicated by infective endocarditis, and 2 patients died of multiorgan failure. CONCLUSIONS: Delayed sternal closure was not a major risk factor for mediastinitis, especially if primary skin closure was used with delayed sternal closure. Excellent results were attained with debridement and primary closure of these infections.

Adolescent↗

PubMed2004

Calreticulin in the heart.

Calreticulin is a Ca2+ binding/storage chaperone resident protein of the endoplasmic reticulum. This protein plays a key role in the calreticulin/calnexin cycle and the quality control pathways in the endoplasmic reticulum. Calreticulin deficiency is lethal due to impaired cardiac development. However, over-expression of the protein in developing and postnatal heart leads to bradycardia, complete heart block and sudden death. Ultrastructural evidence indicates that the deficiency associated with the absence of calreticulin in the heart may be due to a defect in the development of the contractile apparatus and/or a defect in development of the conductive system as well as a metabolic abnormality. Collectively, we postulate that calreticulin and endoplasmic reticulum plays an important role in cardiac development and postnatal pathologies.

Animals↗