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Biomedical subjects

B M Mayosi

Publications and source records attributed to B M Mayosi.

18 recordsLinked to original sources
PubMed2006

Poikiloderma, tendon contracture and pulmonary fibrosis: a new autosomal dominant syndrome?

Members of two generations of a South African family have a unique syndrome comprising poikiloderma, tendon contractures and progressive pulmonary fibrosis. The condition is clinically important as the skin changes, which involve the face, have considerable cosmetic impact, while lung involvement is potentially lethal in adulthood. Skin manifestations which facilitate diagnosis include facial telangiectasia, mottled hypo- and hyperpigmentation, papules and epidermal atrophy. The scalp, facial and body hair are fine and scanty. The tendon contractures lead to progressive digital flexion deformities and abnormalities of the ankles and feet, with disturbance of gait. Pulmonary involvement manifests as progressive dyspnoea. Pedigree data are compatible with an autosomal dominant mode of transmission. Poikiloderma of Weary is characterized by linear sclerotic and fibrous bands and not tendon contractures and is not associated with potentially lethal pulmonary fibrosis. Rather than name this disorder a variant of Weary syndrome, it might be prudent to use as an umbrella title one composed by Weary himself: 'hereditary sclerosing poikiloderma' (HSP), under which variants such as HSP Weary type, HSP with cardiac involvement (aortic stenosis described as inconsistently associated with Weary syndrome) and HSP with tendon/pulmonary involvement (current family) may be classified. The manifestations in this family differ from other poikilodermata and, to the best of our knowledge, have not been previously documented.

Adult↗
PubMed2006

Notification of rheumatic fever in South Africa -- evidence for underreporting by health care professionals and administrators.

OBJECTIVE: To determine whether under-reporting of rheumatic fever occurs at hospital, municipal, provincial and national levels of the South African health system. BACKGROUND: Information on the incidence of rheumatic fever (RF) and the prevalence of rheumatic heart disease (RHD) is required for the prevention of valvular heart disease in developing countries. In South Africa, RF was made a notifiable condition in 1989. It has recently been suggested that the reporting of RF cases may be incomplete, possibly because of underreporting by health care professionals and deficient administration of the disease notification system in South Africa. METHOD AND RESULTS: We assessed whether underreporting of RF cases occurs by comparing the numbers of RF cases reported per year at hospital, municipal, provincial and national levels from 1990 to 2004. There was a fall in the number of RF cases reported per year at national and provincial level over the 15 years of observation. A detailed analysis of the number of RF cases reported at hospital, municipal and provincial level for a 5-year period showed that more cases were diagnosed in one hospital (serving a smaller population) than were captured at municipal and provincial level (serving a larger population), suggesting underreporting by health care professionals. There were discrepancies in the number of cases reported at municipal, provincial and national level, suggesting poor administration of the notification system. CONCLUSION: There appears to be underreporting of RF cases by health care professionals, and poor administration of the RF notification system. Health care professionals need to be educated about the statutory requirement to notify all RF cases in South Africa. An effective national disease notification system is required.

Data Collection↗
PubMed2005

Heterozygous disruption of SERCA2a is not associated with impairment of cardiac performance in humans: implications for SERCA2a as a therapeutic target in heart failure.

OBJECTIVE: To verify whether a deficiency in the cardiac sarcoplasmic reticulum pump SERCA2a causes cardiac dysfunction in humans. DESIGN: Cardiac performance was measured in a serendipitous human model of primary SERCA2a deficiency, Darier's disease, an autosomal dominant skin disorder caused by mutations inactivating one copy of the ATP2A2 gene, which encodes SERCA2a. METHODS: Systolic and diastolic function and contractility were assessed by echocardiography at rest and during exercise in patients with Darier's disease with known mutations. Fourteen patients with Darier's disease were compared with 14 normal controls and six patients with dilated cardiomyopathy with stable heart failure. RESULTS: Resting systolic and diastolic function was normal in patients with Darier's disease and in controls. The increase in systolic function during exercise was not different between patients with Darier's disease and normal controls; neither was there a difference in contractility. As expected, patients with dilated cardiomyopathy had impaired diastolic and systolic function with depressed contractility at rest and during exercise. CONCLUSION: Contrary to expectations, heterozygous disruption of SERCA2a is not associated with the impairment of cardiac performance in humans. Attempts to increase SERCA2a levels in heart failure, although showing promise in rodent studies, may not be addressing a critical causal pathway in humans.

Calcium-Transporting ATPases↗
PubMed2005

A rare variant of the leptin gene has large effects on blood pressure and carotid intima-medial thickness: a study of 1428 individuals in 248 families.

BACKGROUND: Rare mutations in the leptin (LEP) gene cause severe obesity. Common polymorphisms of LEP have been associated with obesity, but their association with cardiovascular disease has been little studied. We have examined the impact of both common and rare polymorphisms of the LEP gene on blood pressure (BP), subclinical atherosclerosis as measured by carotid intima-medial thickness (CIMT), and body mass index (BMI) in a large family study. METHODS: Five polymorphisms spanning LEP were typed in 1428 individuals from 248 nuclear families. BP, CIMT, BMI, and plasma leptin were measured. RESULTS: The polymorphisms typed captured all common haplotypes present at LEP. There was strong association between a rare polymorphism in the 3' untranslated region of LEP (C538T) and both pulse pressure (p = 0.0001) and CIMT (p = 0.008). C/T heterozygotes had a 22% lower pulse pressure and a 17% lower CIMT than C/C homozygotes. The polymorphism accounted for 3-5% of the population variation in pulse pressure and CIMT. There was no association between any LEP polymorphism and either BMI or plasma leptin level. CONCLUSIONS: This large family study shows that the rare T allele at the C538T polymorphism of LEP substantially influences pulse pressure and CIMT, but does not appear to exert this effect through actions on plasma leptin level or BMI. This suggests that autocrine or paracrine effects in vascular tissue may be important physiological functions of leptin. This study also provides evidence that rare polymorphisms of particular genes may have substantial effects within the normal range of certain quantitative traits.

Atherosclerosis↗
PubMed2003

Utilization of implantable defibrillators in Africa.

Sub-Saharan Africa is dominated by diseases of poverty. HIV/AIDS affects 28.5 out of a total of 600 million in the region. South Africa is the only country in sub-Saharan Africa in which implantable cardiovertor defibrillators (ICDs) are implanted (0.8/million in 2001). Only 3 of the 35 new ICDs were implanted in state-funded public hospitals. The pacemaker implantation rate for South Africa was 41/million in 2001. Approximately 20% of the population consume 56% of the health care expenditure, mainly funded by Medical Insurance. A tax-funded state health care system serves the rest of the population, but is concentrated on improving sanitation and primary health care. Diversion of funds from academic tertiary hospitals has reduced specialised services, particularly cardiology and cardiac surgery, and has resulted in an exodus of skilled personnel to the private sector. In the rest of sub-Saharan Africa, tertiary health care is mainly privately funded. Cardiology and cardiac surgery is not widely available. Many countries are crippled by debt and chronic local conflicts. Only one state hospital (Groote Schuur, Cape Town) provides an electrophysiology (EP) service including catheter ablation and ICD implantation, and training in EP, by two electrophysiologists. EP services are available privately in 3 centres. No EP service exists in the rest of sub-Saharan Africa.

Africa↗
PubMed2003

Adjuvant corticosteroids for tuberculous pericarditis: promising, but not proven.

BACKGROUND: There is controversy regarding the effectiveness of corticosteroids in tuberculous pericarditis, particularly in patients who are immunocompromised by HIV. AIM: To determine the effectiveness of adjuvant corticosteroids in tuberculous pericarditis. DESIGN: Systematic review of randomized controlled trials. METHODS: We searched the Cochrane Infectious Diseases Group trials register (June 2002), the Cochrane Controlled Trials Register (Issue 2, 2002), MEDLINE (January 1966 to March 2003), EMBASE (1980 to May 2002), and the reference lists of existing reviews, for randomized and quasi-randomized controlled trials of adjuvant corticosteroids in the treatment of suspected tuberculous pericarditis. We also contacted organizations and individuals working in the field. Two reviewers independently assessed trial quality and extracted data. We used meta-analysis with a fixed effects model to calculate the summary statistics, provided there was no statistically significant heterogeneity, and expressed results as relative risk. RESULTS: Four trials with a total of 469 participants met our criteria. Three (total n = 411) tested adjuvant steroids in participants with suspected tuberculous pericarditis in the pre-HIV era. Fewer participants died in the intervention group, but the potentially large reduction in mortality was not statistically significant (relative risk RR 0.65, 95%CI 0.36-1.16, n = 350; p = 0.14). One trial with 58 patients that enrolled HIV-positive individuals also showed a promising but non-significant trend on mortality (RR 0.50, 95%CI 0.19-1.28; p = 0.15). There was no significant beneficial effect of steroids on re-accumulation of pericardial effusion or progression to constrictive pericarditis. Patients with pericardial effusion were significantly more likely to be alive with no functional impairment at 2 years following treatment. However, the effect was not sustained in a sensitivity analysis that included patients who were lost to follow-up. DISCUSSION: Steroids could have large beneficial effects on mortality and morbidity in tuberculous pericarditis, but published trials are too small to be conclusive. Large placebo-controlled trials are required, and should include sufficient numbers of HIV-positive and HIV-negative participants, and an adequate adjuvant steroid dose.

Adrenal Cortex Hormones↗
PubMed2002

Penicillin for secondary prevention of rheumatic fever.

BACKGROUND: People with a history of rheumatic fever are at high risk of recurrent attacks of rheumatic fever and developing rheumatic heart disease following a streptococcal throat infection. Giving penicillin to these people can prevent recurrent attacks of rheumatic fever and subsequent rheumatic heart disease. However, there is no agreement on the most effective method of giving penicillin. OBJECTIVES: To assess the effects of penicillin compared to placebo and the effects of different penicillin regimens and formulations for preventing streptococcal infection and rheumatic fever recurrence. SEARCH STRATEGY: We searched the Controlled Trials Register (Cochrane Library Issue 2, 2001), MEDLINE (1997 to July 2000), EMBASE (1998 to July 2000), reference lists of articles and we contacted experts in the field. SELECTION CRITERIA: Randomised and quasi-randomised studies comparing (i) penicillin with control, (ii) oral with intramuscular penicillin (iii) 2- or 3-weekly with 4-weekly intramuscular penicillin in patients with previous rheumatic fever. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. MAIN RESULTS: Nine studies were included (n=3008). Data were not pooled because of heterogeneity. Overall, the methodological quality of included studies was poor. Three trials (n= 1301) compared penicillin with control. Only one of three studies showed that penicillin reduced rheumatic fever recurrence (RR 0.45, 95% CI 0.22 to 0.92) and streptococcal throat infection (RR 0.84, 95% CI 0.72 to 0.97). Four trials (n=1098) compared intramuscular with oral penicillin and all showed that intramuscular penicillin reduced rheumatic fever recurrence and streptococcal throat infections compared to oral penicillin. One trial (n= 360) compared 2-weekly with 4-weekly intramuscular penicillin. Penicillin given every two-weeks was better at reducing rheumatic fever recurrence (RR 0.52, 95% CI 0.33 to 0.83) and streptococcal throat infections (RR 0.60, 95% CI 0.42 to 0.85). One trial (n= 249) showed 3-weekly intramuscular penicillin injections reduced streptococcal throat infections (RR 0.67, 95% CI 0.48 to 0.92) compared to 4-weekly intramuscular penicillin. REVIEWER'S CONCLUSIONS: Intramuscular penicillin seemed to be more effective than oral penicillin in preventing rheumatic fever recurrence and streptococcal throat infections. Two-weekly or 3-weekly injections appeared to be more effective than 4-weekly injections. However, the evidence is based on poor quality of trials.

Administration, Oral↗
PubMed2002

Electrocardiographic measures of left ventricular hypertrophy show greater heritability than echocardiographic left ventricular mass.

AIMS: To assess the heritability (i.e. relative contribution of genetic factors to the variability) of continuous measures of left ventricular hypertrophy determined by electrocardiography and echocardiography. METHODS AND RESULTS: We studied 955 members of 229 Caucasian families, ascertained through a hypertensive proband. Electrocardiographic measurements were performed manually on resting 12-lead electrocardiograms, and echocardiographic measurements were made on M-mode images. Sex-specific residuals for the left ventricular phenotypes were calculated, adjusted for age, systolic blood pressure, weight, height, waist-hip ratio, and presence of diabetes. Heritability was estimated in two ways: firstly, from familial correlations with adjustment for spouse resemblance; and secondly by using variance components methods with ascertainment correction for proband status. The heritability estimates (given as a range derived from the two methods) were higher for Sokolow-Lyon voltage (39-41%) than for echocardiographic left ventricular mass (23-29%). Electrocardiographic left ventricular mass, Cornell voltage, and Cornell product had heritability estimates of 12-18%, 19-25%, and 28-32%, respectively. CONCLUSIONS: Genetic factors may explain a substantial proportion of variability in quantitative electrocardiographic and echocardiographic measures of left ventricular hypertrophy. The greater heritability of Sokolow-Lyon voltage suggests that electrocardiographic phenotypes may be particularly important for the molecular investigation of the genetic susceptibility to cardiac hypertrophy.

Echocardiography↗
PubMed2001

A common mitochondrial DNA variant associated with susceptibility to dilated cardiomyopathy in two different populations.

Idiopathic dilated cardiomyopathy is a recognised manifestation of mitochondrial disease due to specific mitochondrial (mt) DNA mutations. However, whether mtDNA polymorphisms predispose to sporadic dilated cardiomyopathy is not known. We analysed two populations with this disorder for a general mtDNA variant (T16189C), previously implicated in susceptibility to type 2 diabetes. We noted an increased frequency of the polymorphism in both populations compared with controls (p=0.002). The polymorphism occurred on different mtDNA backgrounds, suggesting that it might be a functional variant. This association of an mtDNA variant with increased susceptibility to dilated cardiomyopathy provides evidence for a mitochondrial cause in sporadic disease.

Adolescent↗
PubMed2000

Interventions for treating tuberculous pericarditis.

BACKGROUND: Tuberculous (TB) pericarditis is becoming more common. The infection can result in fluid around the heart, which can be fatal. OBJECTIVES: To evaluate evidence from trials about the effects of medical and surgical treatments for TB pericarditis on death and life-threatening conditions. SEARCH STRATEGY: The Cochrane Infectious Diseases Group trials register, the Cochrane controlled trials register, Medline, Embase and reference lists of articles; contact with experts in the field. SELECTION CRITERIA: Randomised and quasi-randomised trials of treatments for TB pericarditis. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Meta-analysis using fixed effects models calculated summary statistics, provided there was no significant heterogeneity, and expressed results as relative risk. MAIN RESULTS: Three trials met the inclusion criteria, with a total of 411 participants. Treatments were adjuvant steroids and surgical drainage. Two small trials tested steroids. There were fewer deaths (all causes) in the intervention group, but the numbers were small and the result could have occurred by chance (relative risk [RR] 0.65, 95% confidence interval [CI] 0.36 to 1.16, n = 350). In one trial studying patients with effusion, "cure" was higher in the steroid group (alive and free of disability at 2 years (RR 0.69, 95% CI 0.29 to 0.80, n = 221). One trial examined open surgical drainage compared with conservative management, and showed no impact of surgery on death, but a protective effective against cadiac tamponade (RR 0.04, 95% CI 0.00 to 0.64). REVIEWER'S CONCLUSIONS: Steroids have potentially large impacts on survival, but trials are too small to test this. We believe further placebo controlled trials of steroids are warranted, exploring whether the presence of effusion or fibrosis modifies effects. Surgical options also require further evaluation.

Adrenal Cortex Hormones↗
PubMed1999

Long-term survival after permanent pacemaker implantation in young adults: 30 year experience.

The goal of the present study was to determine the etiology of conduction disease and long-term outcome for young adults who undergo permanent pacemaker implantation. Permanent pacing was performed in 232 patients aged 21-50 years, 135 males and 97 females, from 1965 through 1995. One hundred and twenty-six subjects (54%) had evidence of structural heart disease, while idiopathic conduction disease accounted for 46%. About half (54%) of 106 patients with structural heart disease had surgically induced heart block. Pacing mode at primary implantation was single chamber in 65% and dual chamber in 35%. Follow-up ranged from 12-387 months, with a mean of 104-months. At the last follow-up, 133 of 232 patients (57%) were alive, 40 (17%) had died, 30 (13%) were lost to follow-up, 26 (11%) were transferred elsewhere, and 3 (1%) explanted. Patients with sick sinus syndrome had similar outcomes to those with AV block. There was a sharp decline in survival during the first six months; 7.5% of the sample died within the first year following their first pacemaker operation. After the first year, the decline in survival slowed and 70% of the patients could be expected to survive beyond 20 years. The overall survival of young patients without structural heart disease who received a permanent pacemaker was comparable to an age- and sex-matched control population, while patients with structural heart disease performed significantly worse than the control population.

Adult↗
PubMed1996

Pulmonary edema following electrical cardioversion of atrial fibrillation.

A 61-year-old man with hypertrophic cardiomyopathy developed acute pulmonary edema 29 h following cardioversion of chronic atrial fibrillation to sinus rhythm. Doppler echocardiographic evaluation of atrial function showed return of right atrial contraction but absent left atrial systole. This has not been reported previously in a case of postcardioversion pulmonary edema.

Atrial Fibrillation↗