Burden of disease and barriers to comprehensive care for rheumatic heart disease in South Africa: an updated systematic review protocol.

INTRODUCTION: Rheumatic heart disease (RHD) is responsible for a significant burden of cardiovascular morbidity and mortality, and remains the most common cause of acquired heart disease among children and young adults in low-income and middle-income countries. Additionally, the global COVID-19 pandemic has forced the emergency restructuring of many health systems, which has had a broad impact on health in general, including cardiovascular disease. Despite significant cost to the health system and estimates from 2015 indicating both high incidence and prevalence of RHD in South Africa, no cohesive national strategy exists. An updated review of national burden of disease estimates, as well as literature on barriers to care for patients with RHD, will provide crucial information to assist in the development of a national RHD programme. METHODS AND ANALYSIS: Using predefined search terms that capture relevant disease processes from Group A Streptococcal (GAS) infection through to the sequelae of RHD, a search of PubMed, Scopus, ISI Web of Science, Sabinet African Journals, SA Heart and Current and Completed Research databases will be performed. All eligible studies on RHD, acute rheumatic fever and GAS infection published from April 2014 to December 2022 will be included. Vital registration data for the same period from Statistics South Africa will also be collected. A standardised data extraction form will be used to capture results for both quantitative and qualitative analyses. All studies included in burden of disease estimates will undergo quality assessment using standardised tools. Updated estimates on mortality and morbidity as well as a synthesis of work on primary, secondary and tertiary prevention of RHD will be reported. ETHICS AND DISSEMINATION: No ethics clearance is required for this study. Findings will be disseminated in a peer-reviewed journal and submitted to national stakeholders in RHD. PROSPERO REGISTRATION NUMBER: CRD42023392782.

Methionine synthase deficiency: Variable clinical presentation and benefit of early diagnosis and treatment.

Methionine synthase deficiency (cblG complementation group) is a rare inborn error of metabolism affecting the homocysteine re-methylation pathway. It leads to a biochemical phenotype of hyperhomocysteinemia and hypomethioninemia. The clinical presentation of cblG is variable, ranging from seizures, encephalopathy, macrocytic anemia, hypotonia, and feeding difficulties in the neonatal period to onset of psychiatric symptoms or acute neurologic changes in adolescence or adulthood. Given the variable and nonspecific symptoms seen in cblG, the diagnosis of affected patients is often delayed. Medical management of cblG includes the use of hydroxocobalamin, betaine, folinic acid, and in some cases methionine supplementation. Treatment has been shown to lead to improvement in the biochemical profile of affected patients, with lowering of total homocysteine levels and increasing methionine levels. However, the published literature contains differing conclusions on whether treatment is effective in changing the natural history of the disease. Herein, we present five patients with cblG who have shown substantial clinical benefit from treatment with objective improvement in their neurologic outcomes. We demonstrate more favorable outcomes in our patients who were treated early in life, especially those who were treated before neurologic symptoms manifested. Given improved outcomes from treatment of presymptomatic patients, cblG warrants inclusion in newborn screening.

Methionine dependence in tumor cells: The potential role of cobalamin and MMACHC.

Methionine dependence of tumor cell lines, the inability to grow in tissue culture media lacking methionine but supplemented with homocysteine, has been known for decades, but an understanding of the mechanism underlying this phenomenon remains incomplete. Methionine dependence of certain glioma and melanoma cell lines has been linked to alterations in the metabolism of cobalamin (vitamin B12). In the MeWo LC1 melanoma line, complementation analysis demonstrated that the genetic defect affected the same locus mutated in the cblC inborn error of cobalamin metabolism; hypermethylation of the MMACHC promoter was subsequently demonstrated. Analysis of data in the Cancer Cell Line Encyclopedia showed increased MMACHC methylation levels in melanoma lines compared to other types of cancer. RNA sequencing data from isolated tumors, tabulated at the cBioPortal for Cancer Genomics website, showed decreased MMACHC expression compared to other tumors; and methylation data tabulated at the TGGA Wanderer website demonstrated increased MMACHC methylation. These data suggest that disruptions in cobalamin metabolism might play a more general role in methionine dependence, and potentially in the pathogenesis of melanoma cell lines and primary tumors.

MRI Tumor Regression Grade and Circulating Tumor DNA as Complementary Tools to Assess Response and Guide Therapy Adaptation in Rectal Cancer.

PURPOSE: Response to preoperative chemo-radiotherapy (CRT) varies. We assessed whether circulating tumor DNA (ctDNA) might be an early indicator of tumor response or progression to guide therapy adaptation in rectal cancer. EXPERIMENTAL DESIGN: A total of 243 serial plasma samples were analyzed from 47 patients with localized rectal cancer undergoing CRT. Up to three somatic variants were tracked in plasma using droplet digital PCR. RECIST and MRI tumor regression grade (mrTRG) evaluated response. Survival analyses applied Kaplan-Meier method and Cox regression. RESULTS: ctDNA detection rates were: 74% (n = 35/47) pretreatment, 21% (n = 10/47) mid CRT, 21% (n = 10/47) after completing CRT, and 13% (n = 3/23) after surgery. ctDNA status after CRT was associated with primary tumor response by mrTRG (P = 0.03). With a median follow-up of 26.4 months, metastases-free survival was shorter in patients with detectable ctDNA after completing CRT [HR 7.1; 95% confidence interval (CI), 2.4-21.5; P < 0.001], persistently detectable ctDNA pre and mid CRT (HR 3.8; 95% CI, 1.2-11.7; P = 0.02), and pre, mid, and after CRT (HR 11.5; 95% CI, 3.3-40.4; P < 0.001) compared with patients with undetectable or nonpersistent ctDNA. In patients with detectable ctDNA, a fractional abundance threshold of ≥0.07% mid CRT or ≥0.13% after completing CRT predicted for metastases with 100% sensitivity and 83.3% specificity for mid CRT and 66.7% for CRT completion. All 3 patients with detectable ctDNA post-surgery relapsed compared with none of the 20 patients with undetectable ctDNA (P = 0.001). CONCLUSIONS: ctDNA identified patients at risk of developing metastases during the neoadjuvant period and post-surgery, and could be used to tailor treatment.

Genome and RNA sequencing in patients with methylmalonic aciduria of unknown cause.

PURPOSE: Our laboratory has classified patients with methylmalonic aciduria using somatic cell studies for over four decades. We have accumulated 127 fibroblast lines from patients with persistent elevated methylmalonic acid (MMA) levels in which no genetic cause could be identified. Cultured fibroblasts from 26 of these patients had low [14C]propionate incorporation into macromolecules, possibly reflecting decreased methylmalonyl-CoA mutase function. METHODS: Genome sequencing (GS), copy-number variation (CNV) analysis, and RNA sequencing were performed on genomic DNA and complementary DNA (cDNA) from these 26 patients. RESULTS: No patient had two pathogenic variants in any gene associated with cobalamin metabolism. Nine patients had heterozygous variants of unknown significance previously identified by a next-generation sequencing (NGS) panel targeting cobalamin metabolic genes. Three patients had pathogenic changes in genes not associated with cobalamin metabolism (PCCA, EPCAM, and a 17q12 duplication) that explain parts of their phenotypes other than elevated MMA. CONCLUSION: Genome and RNA sequencing did not detect any additional putative causal genetic defects in known cobalamin genes following somatic cell studies and the use of a targeted NGS panel. They did detect pathogenic variants in other genes in three patients that explained some aspects of their clinical presentation.

Integrating the prevention and control of rheumatic heart disease into country health systems: a systematic review protocol.

INTRODUCTION: Rheumatic heart disease (RHD) is a preventable chronic condition affecting the valves of the heart. RHD prevention and care programmes have historically originated in more developed countries, implemented in a targeted (or vertical) manner and evaluated using non-controlled approaches. Taking a broad view of the integration of RHD activities within the whole system is critical for health planning in low-income regions with a high burden of RHD and less robust health systems. Therefore, we propose to conduct a systematic review to assess RHD programme models in order to gain a better understanding of the extent of integration within relevant health systems. METHODS AND ANALYSIS: A predefined search strategy will be used to search for relevant articles published in English from January 1990 to December 2017. Electronic databases PubMed, Scopus, Web of Science, Africa Wide, CINAHL, Cochrane Central Register of Controlled Trials, Google Scholar and Global Index Medicus will be searched, as well as reference lists of relevant articles published. A standardised data extraction form will be used to obtain information for analysis from the included studies. The quality, reliability and risk of bias of included studies will be assessed using design-specific criteria. Programme integration will be analysed according to stewardship and governance, financing, planning, service delivery, monitoring and evaluation, and demand generation. Programme inputs, outputs and impact will also be described. ETHICS AND DISSEMINATION: No ethical approval is required. Findings will be disseminated in a peer-review journal in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. PROSPERO REGISTRATION NUMBER: CRD42017076307.

Sacrificial Cobalt-Carbon Bond Homolysis in Coenzyme B12 as a Cofactor Conservation Strategy.

A sophisticated intracellular trafficking pathway in humans is used to tailor vitamin B12 into its active cofactor forms, and to deliver it to two known B12-dependent enzymes. Herein, we report an unexpected strategy for cellular retention of B12, an essential and reactive cofactor. If methylmalonyl-CoA mutase is unavailable to accept the coenzyme B12 product of adenosyltransferase, the latter catalyzes homolytic scission of the cobalt-carbon bond in an unconventional reversal of the nucleophilic displacement reaction that was used to make it. The resulting homolysis product binds more tightly to adenosyltransferase than does coenzyme B12, facilitating cofactor retention. We have trapped, and characterized spectroscopically, an intermediate in which the cobalt-carbon bond is weakened prior to being broken. The physiological relevance of this sacrificial catalytic activity for cofactor retention is supported by the significantly lower coenzyme B12 concentration in patients with dysfunctional methylmalonyl-CoA mutase but normal adenosyltransferase activity.

Costs and cost-effectiveness of HIV/noncommunicable disease integration in Africa: from theory to practice.

: The current article reviews economic aspects of selected HIV/noncommunicable disease (NCD) service delivery integration programs to assess the efficiency of integration in limited capacity settings. We define economies of scope and scale and their relevance to HIV/NCD integration. We summarize the results of a systematic review of cost and cost-effectiveness studies of integrated care, which identified 12 datasets (nine studies) with a wide range of findings driven by differences in research questions, study methods, and health conditions measured. All studies were done in Africa and examined screening interventions only. No studies assessed the cost of integrated, long-term disease management. Few studies estimated the cost-effectiveness of integrated screening programs. The additional cost of integrating NCD screening with HIV care platforms represented a 6-30% increase in the total costs of the programs for noncancer NCDs, with cervical cancer screening costs dependent on screening strategy. We conducted 11 key informant interviews to uncover perceptions of the economics of HIV/NCD integration. None of the informants had hard information about the economic efficiency of integration. Most expected integrated care to be more cost-effective than current practice, though a minority thought that greater specialization could be more cost-effective. In the final section of this article, we summarize research needs and propose a 'minimum economic dataset' for future studies. We conclude that, although integrated HIV/NCD care has many benefits, the economic justification is unproven. Better information on the cost, cost-effectiveness, and fiscal sustainability of integrated programs is needed to justify this approach in limited-resource countries.

What Is the Predictive Value of Animal Models for Vaccine Efficacy in Humans? Rigorous Simian Immunodeficiency Virus Vaccine Trials Can Be Instructive.

Simian immunodeficiency virus (SIV) challenge of rhesus macaques provides an invaluable tool to evaluate the clinical prospects of HIV-1 vaccine concepts. However, as with any animal model of human disease, it is crucial to understand the advantages and limitations of this system to maximize the translational value of SIV vaccine studies. Here, we discuss the importance of assessing the efficacy of vaccine prototypes using stringent SIV challenge regimens that mimic HIV-1 transmission and pathogenesis. We also review some of the cautionary tales of HIV-1 vaccine research because they provide general lessons for the preclinical assessment of vaccine candidates.

Seven key actions to eradicate rheumatic heart disease in Africa: the Addis Ababa communiqué.

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) remain major causes of heart failure, stroke and death among African women and children, despite being preventable and imminently treatable. From 21 to 22 February 2015, the Social Cluster of the Africa Union Commission (AUC) hosted a consultation with RHD experts convened by the Pan-African Society of Cardiology (PASCAR) in Addis Ababa, Ethiopia, to develop a 'roadmap' of key actions that need to be taken by governments to eliminate ARF and eradicate RHD in Africa. Seven priority areas for action were adopted: (1) create prospective disease registers at sentinel sites in affected countries to measure disease burden and track progress towards the reduction of mortality by 25% by the year 2025, (2) ensure an adequate supply of high-quality benzathine penicillin for the primary and secondary prevention of ARF/RHD, (3) improve access to reproductive health services for women with RHD and other non-communicable diseases (NCD), (4) decentralise technical expertise and technology for diagnosing and managing ARF and RHD (including ultrasound of the heart), (5) establish national and regional centres of excellence for essential cardiac surgery for the treatment of affected patients and training of cardiovascular practitioners of the future, (6) initiate national multi-sectoral RHD programmes within NCD control programmes of affected countries, and (7) foster international partnerships with multinational organisations for resource mobilisation, monitoring and evaluation of the programme to end RHD in Africa. This Addis Ababa communiqué has since been endorsed by African Union heads of state, and plans are underway to implement the roadmap in order to end ARF and RHD in Africa in our lifetime.

Severe combined immunodeficiency resulting from mutations in MTHFD1.

Folate and vitamin B(12) metabolism are essential for de novo purine synthesis, and several defects in these pathways have been associated with immunodeficiency. Here we describe the occurrence of severe combined immunodeficiency (SCID) with megaloblastic anemia, leukopenia, atypical hemolytic uremic syndrome, and neurologic abnormalities in which hydroxocobalamin and folate therapy provided partial immune reconstitution. Whole exome sequencing identified compound heterozygous mutations in the MTHFD1 gene, which encodes a trifunctional protein essential for processing of single-carbon folate derivatives. We now report the immunologic details of this novel genetic cause of SCID and the response to targeted metabolic supplementation therapies. This finding expands the known metabolic causes of SCID and presents an important diagnostic consideration given the positive impact of therapy.

A comparative environmental life-cycle analysis for removing phosphorus from wastewater: biological versus physical/ chemical processes.

Phosphorus can be removed from wastewater biologically, chemically, or through a combination of the two. In this study, we applied environmental life-cycle assessment to develop a metric with which decision-makers can compare processes. Two phosphorus-removal scenarios were contrasted-one based on a desktop-level design and one based on full-scale operational data. To achieve 0.5 mg/L effluent phosphorus (desktop design), a biological-only process would incur 5.2% less effect on global warming potential, as contrasted with a chemical-only process. At an effluent quality of 0.1 mg/L (full-scale facilities), where a biological process augmented with chemicals was contrasted with a chemical-only process, the relative gap increases to 13.2%. As chemical usage increased, the adverse environmental effect of chemical treatment only increased. The results of this study suggest that best practices would center phosphorus removal first on the biological process, with chemical processes added only as necessary.

Effect of anaerobic HRT on biological phosphorus removal and the enrichment of phosphorus accumulating organisms.

The purpose of this research was to develop a better understanding of the dynamic effects of anaerobic hydraulic retention time (HRT) on both enhanced biological phosphorus removal (EBPR) performance and enrichment of phosphorus accumulating organisms (PAOs). The research was conducted using laboratory-scale sequencing batch reactors inoculated with mixed microbial consortia and fed real wastewater. Exposing microorganisms to extended anaerobic HRTs is not recommended for EBPR configured systems. In this research, however, longer anaerobic exposure did not negatively affect performance even if volatile fatty acids were depleted. Further, extended anaerobic HRTs may positively affect phosphorus removal through enhanced aerobic uptake. The EBPR consortia also appear to maintain reserve energetic capacity in the form of polyphosphate that can be used to survive and grow under variable operational and environmental conditions. Finally, the tested EBPR systems yield mixed microbial consortia enriched with PAOs (specifically Candidatus Accumulibacter phosphatis) at approximately 7.1 to 21.6% of the total population.

Longitudinal assessment of quality of life in rectal cancer patients with or without stomas following primary resection.

PURPOSE: The purpose of this study was to assess the longitudinal impact of stoma formation on the health-related quality of life of rectal cancer patients treated with adjuvant chemotherapy. METHODS: Health-related quality of life data was prospectively collected in a randomized trial designed to compare 24 weeks of bolus 5-fluorouracil/leucovorin with 12 weeks of continuous 5-fluorouracil in patients with resected Dukes B and C colorectal cancer. Health-related quality of life data was collected at baseline, during adjuvant treatment, and at one and three years after completion of chemotherapy. RESULTS: Between 1993 and 2003, 186 rectal cancer patients were enrolled. One hundred thirty-nine patients had anterior resection, of whom 46 had a temporary defunctioning colostomy. Forty-seven patients had abdominoperineal resection with formation of a permanent colostomy. There was no significant difference in global health-related quality of life between patients with and patients without a stoma at any time point. However, during adjuvant treatment, role (P = 0.04) and social (P = 0.005) functioning were significantly worse in stoma patients than in nonstoma patients. Moreover, the impairment in social functioning persisted at one (P = 0.03) and three years (P = 0.04) after adjuvant chemotherapy. CONCLUSION: Our results demonstrate important adverse effects of either temporary or permanent stoma formation on subsequent health-related quality of life in patients with rectal cancer.

Epigenetic modification of the gene for the vitamin B(12) chaperone MMACHC can result in increased tumorigenicity and methionine dependence.

Methionine dependence, the inability of cells to grow when the amino acid methionine is replaced in culture medium by its metabolic precursor homocysteine, is characteristic of many cancer cell lines and some tumors in situ. Most cell lines proliferate normally under these conditions. The methionine dependent tumorigenic human melanoma cell line MeWo-LC1 was derived from the methionine independent non-tumorigenic line, MeWo. MeWo-LC1 has a cellular phenotype identical to that of cells from patients with the cblC inborn error of cobalamin metabolism, with decreased synthesis of cobalamin coenzymes and decreased activity of the cobalamin-dependent enzymes methionine synthase and methylmalonylCoA mutase. Inability of cblC cells to complement the defect in MeWo-LC1 suggested that it was caused by decreased activity of the MMACHC gene. However, no potentially disease causing mutations were detected in the coding sequence of MMACHC in MeWo-LC1. No MMACHC expression was detected in MeWo-LC1 by quantitative or non-quantitative PCR. There was virtually complete methylation of a CpG island at the 5'-end of the MMACHC gene in MeWo-LC1, consistent with inactivation of the gene by methylation. The CpG island was partially methylated (30-45%) in MeWo and only lightly methylated (2-11%) in control fibroblasts. Infection of MeWo-LC1 with wild type MMACHC resulted in correction of the defect in cobalamin metabolism and restoration of the ability of cells to grow in medium containing homocysteine. We conclude that epigenetic inactivation of the MMACHC gene is responsible for methionine dependence in MeWo-LC1.

Update on cobalamin, folate, and homocysteine.

Three topics affecting cobalamin, folate, and homocysteine that have generated interest, activity, and advances in recent years are discussed. These are: (I). the application of an expanded variety of tools to the diagnosis of cobalamin deficiency, and how these affect and are affected by our current understanding of deficiency; (II). the nature of the interaction between homocysteine and vascular disease, and how the relationship is affected by vitamins; and (III). the improved understanding of relevant genetic disorders and common genetic polymorphisms, and how these interact with environmental influences. The diagnostic approach to cobalamin deficiency now allows better diagnosis of difficult and atypical cases and more confident rejection of the diagnosis when deficiency does not exist. However, the process has also become a complex and sometimes vexing undertaking. Part of the difficulty derives from the lack of a diagnostic gold standard among the many available tests, part from the overwhelming numerical preponderance of patients with subclinical deficiency (in which isolated biochemical findings exist without clinical signs or symptoms) among the cobalamin deficiency states, and part from the decreased availability of reliable tests to identify the causes of a patient's cobalamin deficiency and thus a growing deemphasis of that important part of the diagnostic process. In Section I, Dr. Carmel discusses the tests, the diagnostic issues, and possible approaches to the clinical evaluation. It is suggested no single algorithm fits all cases, some of which require more biochemical proof than others, and that differentiating between subclinical and clinical deficiency, despite their overlap, may be a helpful and practical point of departure in the evaluation of patients encountered in clinical practice. The arguments for and against a suggested expansion of the cobalamin reference range are also weighed. The epidemiologic data suggest that homocysteine elevation is a risk factor for vascular and thrombotic disease. In Section II, Dr. Green notes that the interactions of metabolism and clinical risk are not well understood and a causative relationship remains unproven despite new reports that lowering homocysteine levels may reduce vascular complications. Genetic and acquired influences may interact in important ways that are still being sorted out. The use of vitamins, especially folate, often reduces homocysteine levels but also carries potential disadvantages and even risks. Folate fortification of the diet and supplement use have also markedly reduced the frequency of folate deficiency, and cobalamin deficiency is now the more common deficiency state, especially among the elderly. Although genetic disorders are rare, they illuminate important metabolic mechanisms and pose diagnostic challenges, especially when clinical presentation occurs later in life. In Section III, Drs. Rosenblatt and Watkins use selected disorders to illustrate the subject. Imerslund-Gräsbeck syndrome, a hereditary disorder of cobalamin absorption at the ileal level, demonstrates genetic heterogeneity. Finnish patients show mutation of the gene for cubilin, the multiligand receptor for intrinsic factor. Surprisingly, Norwegian and other patients have been found recently to have mutations of the AMN (amnionless) gene, mutations that are lethal in mice at the embryonic stage. Two disorders of cobalamin metabolism, cblG and cblE, are now known to arise from mutations of the methionine synthase and methionine synthase reductase genes, respectively. These disorders feature megaloblastic anemia and neurologic manifestations. The folate disorder selected for illustration, methylenetetrahydrofolate reductase (MTHFR) deficiency, paradoxically causes neurological problems but no megaloblastic anemia. This rare deficiency is the most common inborn error of folate metabolism. It is distinct from the very common MTHFR gene polymorphisms, mutations that cause mild to moderate reductions in MTHFR activity but no direct clinical manifestations. The MTHFR polymTHFR polymorphisms, especially the 677C-->T mutation, may contribute to vascular and birth defect risks, while reducing the risk of certain malignancies, such as colon cancer. These polymorphisms and those of genes for other enzymes and proteins related to cobalamin, folate, and homocysteine metabolism may be important role players in frequent interactions between genes and the environment.