Mark Sonderup - Academia.edu (original) (raw)

Papers by Mark Sonderup

BMC Global and Public Health, Nov 1, 2023

There are 82 million people living with hepatitis B (PLWHB) in the World Health Organization Afri... more There are 82 million people living with hepatitis B (PLWHB) in the World Health Organization Africa region, where it is the main cause of liver disease. Effective vaccines have been available for over 40 years, yet there are 990,000 new infections annually, due to limited implementation of hepatitis B birth dose vaccination and antenatal tenofovir prophylaxis for highly viraemic women, which could eliminate mother-to-child transmission. Despite effective and cheap antiviral treatment which can suppress hepatitis B virus replication and reduce the risk of hepatocellular carcinoma (HCC), < 2% of PLWHB are diagnosed, and only 0.1% are treated. As a result, PLWHB are frequently diagnosed only when they have already developed decompensated cirrhosis and late-stage HCC, and consequently 80,000 hepatitis B-associated deaths occur each year. Major barriers include complex treatment guidelines which were derived from high-income settings, lack of affordable diagnostics, lack or insufficient domestic funding for hepatitis care, and limited healthcare infrastructure. Current treatment criteria may overlook patients at risk of cirrhosis and HCC. Therefore, expanded and simplified treatment criteria are needed. We advocate for decentralized community treatment programmes, adapted for low-resource and rural settings with limited laboratory infrastructure. We propose a strategy of treat-all except patients fulfilling criteria that suggest low risk of disease progression. Expanded treatment represents a financial challenge requiring concerted action from policy makers, industry, and international donor agencies. It is crucial to accelerate hepatitis B elimination plans, integrate hepatitis B care into existing healthcare programmes, and prioritize longitudinal and implementation research to improve care for PLWHB.

The Lancet Gastroenterology & Hepatology, Oct 31, 2023

Springer eBooks, Dec 31, 2022

South African Gastroenterology Review, 2019

Continuing Medical Education, Nov 1, 2011

BACKGROUND-Mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes (MELAS) is ... more BACKGROUND-Mitochondrial encephalomyopathy, lactic acidosis with stroke-like episodes (MELAS) is a mitochondrial disorder and an important diagnostic consideration in the young patient with nonhemorrhagic stroke. Its presentation is varied and diagnosis is based on early recognition of the clinical features and correct interpretation of laboratory and radiologic studies. SUMMARY-In this article, we report a patient with MELAS and review the clinical, laboratory, and neuroradiologic features of the condition. In the young patient with multiple stroke-like episodes in different vascular territories and neuroradiologic features of transient abnormalities in varying regions, laboratory testing for MELAS must be performed. The presence of ragged red fibers in skeletal muscle and biochemical demonstration of defects in mitochondrial respiratory enzymes strongly support the diagnosis. Molecular genetic testing for abnormalities in mitochondrial DNA will confirm the diagnosis. The importance of a thorough assessment of family history is also emphasized. The basic principles of mitochondrial genetics and the common point mutations and rearrangements of mitochondrial DNA associated with MELAS are reviewed. Although treatment options are limited, several therapeutic agents have been studied. CONCLUSIONS-The diagnosis of MELAS should be considered in the young patient with stroke, especially when accompanied by other clinical features such as seizures, encephalopathy, and muscle weakness. Laboratory evaluation can provide an accurate diagnosis, especially when the appropriate mitochondrial DNA studies are performed. Genetic counseling should be provided to patients with MELAS associated with mitochondrial DNA point mutations. Better understanding of the molecular basis of the condition may result in the development of effective treatment strategies.

South African Medical Journal, Apr 30, 2021

an 80th birthday tribute to him, Tom Bothwell described him as a friendly, warm man with an ebull... more an 80th birthday tribute to him, Tom Bothwell described him as a friendly, warm man with an ebullient, outgoing but relaxed nature who was a highly successful head of a department that he led to new heights with many subspecialty departments, each with their own research programmes. Stuart was also an astute clinician and a mentor to aspiring physicians and researchers. His solid dependability, wise advice, loyalty, integrity, critical thinking and sense of humour set high standards that influenced many. Underlying all his work was his openminded pursuit of clinical and scientific excellence, coupled with interests in the

PubMed, Aug 8, 2018

Globally, 71 million people are thought to be viraemic for hepatitis C. The advent of short cours... more Globally, 71 million people are thought to be viraemic for hepatitis C. The advent of short course all oral direct acting antiviral curative therapy for the virus has put the ideal of the global elimination of this virus within reach. Multiple efforts will be required to achieve this through identifying patients currently infected and preventing further transmission through rapid linkage to treatment while a vaccine remains tenaciously elusive.

CME: Your SA Journal of CPD, Sep 1, 2010

An 18-year-old man with a background of mental retardation and epilepsy presented with a history ... more An 18-year-old man with a background of mental retardation and epilepsy presented with a history of poor seizure control complicated by repeated head trauma and aspiration pneumonia. Notably, he had been on phenytoin since the age of 3.

South African Medical Journal, Nov 27, 2017

Globally, the hepatitis C virus (HCV) is an infection of increasing significance. [1] First clini... more Globally, the hepatitis C virus (HCV) is an infection of increasing significance. [1] First clinically described as a cause of 'non-A, non-B' post-transfusion hepatitis, it was cloned, named, and characterised in 1989. [2] An estimated 170 million people are chronically infected with HCV, predominantly in Africa, Asia, Eastern Europe and South America. [3] HCV is a positive-sense RNA virus of the Flaviviridae family, residing in cell cytoplasm. [2] It infects mostly hepatocytes and can be cleared spontaneously by effective host immune responses in 18-34% of cases. [2] The remainder progress to chronic infection, as the virus evades clearance owing to a variety of immune escape mechanisms. Re-infection can occur spontaneously or after treatment-associated viral clearance. [1,2] Clinical presentation and diagnosis Clinically, HCV is initially asymptomatic. [2] In 20-40% of cases, chronic infection leads to fibrosis, cirrhosis and end-stage liver failure over 20-30 years. [2] Established cirrhosis has a 1-5% annual risk of hepatocellular carcinoma (HCC) and a 3-6% risk of hepatic decompensation. [2] Following hepatic decompensation, the risk of death over the ensuing year is 15-20%. [2] Accelerated progression is associated with co-infection with hepatitis B virus (HBV) and/or HIV, alcohol use, obesity and iron-overload state. [2,4,5] Serological tests confirm HCV exposure and are useful for screening. First-generation HCV IgG ELISA tests were nonspecific, and most current peer-reviewed publications exclude these studies. Second-, third-and fourth-generation serological tests are acceptable, although there are notable accuracy issues in HIV co-infection and among black Africans. [6-8] Region-specific HCV screening algorithms have been developed to try to reliably exclude false positives (≤25%) and to identify resolved, possible acute or possible chronic infection to guide subsequent management. [7-9] The reverse transcriptase polymerase chain reaction (RT-PCR) is the gold standard test for HCV, signifying active infection, and allows for qualitative or quantitative testing. [2] Further nucleic acid tests confirm genotype. Acute HCV infection in HIV-positive patients leads to a long, possibly irregular latency period before seroconversion. Therefore, Kaplan-Lewis and Fierer [10] argue for regular liver function test This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.

Journal of Liver, May 20, 2016

Oxford University Press eBooks, May 1, 2010

Case History—A 35 yr old woman from Southern Africa presenting with abnormal liver blood tests. G... more Case History—A 35 yr old woman from Southern Africa presenting with abnormal liver blood tests. Granuloma formation occurs when persistent antigenaemia or poorly degradable antigens, such as chemicals or toxins, provide an ongoing stimulus that results in the focal accumulation of activated lymphocytes and macrophages, with the macrophages undergoing epithelioid transformation....

South African Medical Journal, Aug 2, 2021

Globally, ~71 million people are viraemic for hepatitis C virus (HCV) infection, with 10.2 millio... more Globally, ~71 million people are viraemic for hepatitis C virus (HCV) infection, with 10.2 million (14%) residing in sub-Saharan Africa. [1] The prevalence of HCV in South Africa (SA) is <1%, with modelled data suggesting ~600 000 infected. [2] Despite typical HCV transmission risks being present in SA, such as people who inject drugs (PWID), pre-1992 blood or blood products (before universal HCV screening was introduced into blood services), parenteral injuries in healthcare workers and traditional practices such as scarification, HCV epidemiology is incompletely characterised. Historically, blood transfusion service HCV incidence, as a marker of the general population in SA, is low at 0.03-0.1%. [3,4] Unsurprisingly, recent data from key populations in SA demonstrate a high prevalence of HCV and HIV-HCV co-infection. [5] HCV prevalence studies in men who have sex with men (MSM) have demonstrated rates of 6%, with genotype (GT) 1a and 3a the predominant genotypes identified. [6] Interestingly, to date no GT5a, an HCV genotype unique to SA, has been identified in any of the key population studies in SA. Local key population data align with global epidemiology as the current major drivers of ongoing HCV infection. [7] Key population patients tend to be younger, the median age being 29 years in SA, whereas the other HCV prevalence peak comprised people invariably >50 years of age. [5,6,8] In recent data from Cape Town looking at a general HCV patient cohort accessing treatment, 26% of patients had no identifiable risk factor, possibly pointing towards other parenteral exposure, e.g. through traditional or unsafe medical practices, as a likely means of transmission. [9] Rwandan data also identified that, in This open-access article is distributed under Creative Commons licence CC-BY-NC 4.0.

South African Gastroenterology Review, Jan 18, 2008

Kupffer cells, hepatic endothelium and hepatocytes all expressCD4 receptors. Infection by HIV-1 c... more Kupffer cells, hepatic endothelium and hepatocytes all expressCD4 receptors. Infection by HIV-1 can be demonstratedalthough, to date, HIV infection of cholangiocytes has not beendocumented. In addition HIV associated mRNA and other HIVassociated proteins can readily be found within hepatocytes.

Liver International, Jul 11, 2021

In December 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐... more In December 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) was identified in Wuhan, China and has since resulted in a global pandemic in excess of 165 million reported infections and 3.4 million attributable deaths. COVID‐19 is primarily a respiratory illness, which may be complicated by pneumonia and acute respiratory distress syndrome. SARS‐CoV‐2 is also responsible for numerous extrapulmonary manifestations involving the haematologic, cardiovascular, renal, gastrointestinal and hepatobiliary, endocrinologic, neurologic, ophthalmologic and dermatologic systems. This review will discuss the pathophysiology of COVID‐19; focusing on the mechanisms and outcomes of liver injury associated with COVID‐19; its impact on chronic liver disease (CLD); management of CLD during the COVID‐19 pandemic and the long‐term impact of COVID‐19 on CLD.

South African Journal of Diabetes, Aug 1, 2011

To understand diseases of iron excess or deficiency, one needs to appreciate the physiology of ir... more To understand diseases of iron excess or deficiency, one needs to appreciate the physiology of iron metabolism. It is thus not surprising that research in the fields of iron metabolism and haemochromatosis have developed side by side for the last 150 years. Iron was first demonstrated to be present in blood in the early 1700's. However, it was almost a century and a half later that a French pathologist would note the first autopsy findings in patients with iron overload. In 1889, Von-Recklinghausen used the term "bronze diabetes". Another century would pass before hereditary haemochromatosis was understood to be an autosomal recessive HLA-linked disease. In a landmark Nature publication in 1996, the HFE gene mutation was described on chromosome 6.