Publications by authors named "Lettow M"

Article Synopsis
  • An analysis of mpox cases in Burundi from July to September 2024 revealed 154 PCR-positive samples out of 607 suspected cases, primarily affecting children under 15.
  • Among the positive cases, a notable proportion were female children, highlighting a gender disparity in infections.
  • The majority of cases were concentrated in Bujumbura Mairie, underlining the need for age- and sex-specific public health interventions and community engagement for effective outbreak containment.
View Article and Find Full Text PDF

Direct RNA nanopore sequencing reveals changes in gene expression, polyadenylation, splicing, m6A methylation, and pseudouridylation in response to influenza virus exposure in primary human bronchial epithelial cells. This study focuses on the epitranscriptomic profile of genes in the host immune response. In addition to polyadenylated noncoding RNA, we purified and sequenced nonpolyadenylated noncoding RNA and observed changes in expression, N6-methyl-adenosine (m6A), and pseudouridylation (Ψ) in these novel RNA.

View Article and Find Full Text PDF

Objectives: The objective of this study is to assess the outcomes of children, adolescents and young adults with HIV reported as lost to follow-up, correct mortality estimates for children, adolescents and young adults with HIV for unascertained outcomes in those loss to follow-up (LTFU) based on tracing and linkage data separately using data from the International epidemiology Databases to Evaluate AIDS in Southern Africa.

Methods: We included data from two different populations of children, adolescents and young adults with HIV; (1) clinical data from children, adolescents and young adults with HIV aged ≤24 years from Lesotho, Malawi, Mozambique, Zambia and Zimbabwe; (2) clinical data from children, adolescents and young adults with HIV aged ≤14 years from the Western Cape (WC) in South Africa. Outcomes of patients lost to follow-up were available from (1) a tracing study and (2) linkage to a health information exchange.

View Article and Find Full Text PDF
Article Synopsis
  • Protonated fucose-containing oligosaccharides often rearrange during mass spectrometry, creating complex fragments that complicate analysis.
  • This study utilizes density functional theory to analyze IR spectra of specific trisaccharides, concluding that they do not undergo rearrangement in the gas phase.
  • Key factors for rearrangement include the presence of a mobile proton and the stability differences between the parent ions and their rearranged forms.
View Article and Find Full Text PDF

Objective: To assess the uptake of services provided by community health workers who were trained as community health entrepreneurs (CHEs) for febrile illness and diarrhoea.

Design: A cross-sectional survey among households combined with mapping of all providers of basic medicine and primary health services in the study area.

Participants: 1265 randomly selected households in 15 rural villages with active CHEs.

View Article and Find Full Text PDF

In recent years, glycosaminoglycans (GAGs) have emerged into the focus of biochemical and biomedical research due to their importance in a variety of physiological processes. These molecules show great diversity, which makes their analysis highly challenging. A promising tool for identifying the structural motifs and conformation of shorter GAG chains is cryogenic gas-phase infrared (IR) spectroscopy.

View Article and Find Full Text PDF

Fucose is a signaling carbohydrate that is attached at the end of glycan processing. It is involved in a range of processes, such as the selectin-dependent leukocyte adhesion or pathogen-receptor interactions. Mass-spectrometric techniques, which are commonly used to determine the structure of glycans, frequently show fucose-containing chimeric fragments that obfuscate the analysis.

View Article and Find Full Text PDF

Evidence suggests children HIV-exposed and uninfected (CHEU) experience poor growth. We analysed child anthropometrics and explored factors associated with stunting among Malawian CHEU. Mothers with HIV and their infants HIV-exposed were enroled in a nationally representative prospective cohort within the National Evaluation of Malawi's Prevention of Mother-to-Child HIV Transmission Programme after Option B+ implementation (2014-2018).

View Article and Find Full Text PDF
Article Synopsis
  • This study focuses on the issue of underestimating mortality rates in antiretroviral therapy programs due to misclassification of deceased patients as lost to follow-up.
  • Researchers used a two-stage inverse probability weighting method to properly account for sample bias when tracing lost patients in Southern Africa from 2017 to 2019.
  • Findings revealed a significant mortality rate of 9.1% among those traced, highlighting the importance of tracer programs to accurately assess and report mortality rates in these vulnerable populations.
View Article and Find Full Text PDF

Background: With the implementation of lifelong antiretroviral therapy (ART) for HIV treatment and prevention, the proportion of children exposed to ART from conception is increasing. We estimated the effect of timing of ART exposure on growth of children HIV-exposed and uninfected (CHEU) up to Up to 24 months of age in Malawi.

Methods: Data were collected from a prospective cohort of infants HIV-exposed aged 1-6 months (enrollment) and their mothers with HIV enrolled in the National Evaluation of Malawi's Prevention of Mother-to-Child Transmission of HIV Programme (2014-2018).

View Article and Find Full Text PDF

Background: Non-communicable diseases (NCDs) such as diabetes and hypertension have become a prominent public health concern in Malawi, where health care services for NCDs are generally restricted to urban centres and district hospitals, while the vast majority of Malawians live in rural settings. Whether similar quality of diabetes care can be delivered at health centres compared to hospitals is not known.

Methods: We implemented a pilot project of decentralized diabetes care at eight health centres in four districts in Malawi.

View Article and Find Full Text PDF

Objectives: Data on long-term HIV-free survival in breastfeeding, HIV-exposed infants (HEIs) are limited. The National Evaluation of Malawi's Prevention of Mother-to-Child Transmission (PMTCT) Program (NEMAPP), conducted between 2014 and 2018, evaluated mother-to-child transmission (MTCT) and infant outcomes up to 24 months postpartum.

Methods: We enrolled a nationally representative cohort of HEIs at 54 health facilities across four regional strata in Malawi and used multivariable Cox regression analysis to investigate the risk of adverse outcomes (HIV transmission, infant death and loss to follow-up) to 24 months postpartum.

View Article and Find Full Text PDF

Cells encode information in the sequence of biopolymers, such as nucleic acids, proteins, and glycans. Although glycans are essential to all living organisms, surprisingly little is known about the "sugar code" and the biological roles of these molecules. The reason glycobiology lags behind its counterparts dealing with nucleic acids and proteins lies in the complexity of carbohydrate structures, which renders their analysis extremely challenging.

View Article and Find Full Text PDF

Objective: To assess implementation and to identify barriers and facilitators to implementation, sustainability and scalability of an implementation strategy to provide lay health workers (LHWs) with the knowledge, skills and tools needed to implement an intervention to support patient tuberculosis (TB) treatment adherence.

Design: Mixed-methods design including a cluster randomised controlled trial and process evaluation informed by the RE-AIM framework.

Setting: Forty-five health centres (HCs) in four districts in the south east zone of Malawi, who had an opportunity to receive cascade training.

View Article and Find Full Text PDF

Background: Attrition threatens the success of antiretroviral therapy (ART). In this cohort study, we examined outcomes of people living with human immunodeficiency virus (PLHIV) who were lost to follow-up (LTFU) during 2014-2017 at ART programs in Southern Africa.

Methods: We confirmed LTFU (missed appointment for ≥60 or ≥90 days, according to local guidelines) by checking medical records and used a standardized protocol to trace a weighted random sample of PLHIV who were LTFU in 8 ART programs in Lesotho, Malawi, Mozambique, South Africa, Zambia, and Zimbabwe, 2017-2019.

View Article and Find Full Text PDF

Glycosaminoglycans (GAGs) are a family of complex carbohydrates vital to all mammalian organisms and involved in numerous biological processes. Chondroitin and dermatan sulfate, an important class of GAGs, are linear macromolecules consisting of disaccharide building blocks of -acetylgalactosamine and two different uronic acids. The varying degree and the site of sulfation render their characterization challenging.

View Article and Find Full Text PDF

The position and configuration of carbon-carbon double bonds in unsaturated fatty acids is crucial for their biological functions and influences health and disease. However, double bond isomers are not routinely distinguished by classical mass spectrometry workflows. Instead, they require sophisticated analytical approaches usually based on chemical derivatization and/or instrument modification.

View Article and Find Full Text PDF

In a previous work, we explored zone broadening and the achievable plate numbers in linear drift tube ion mobility-mass spectrometry through developing a plate-height model [1]. On the basis of these findings, the present theoretical study extends the model by exploring peak-to-peak resolution and peak capacity in ion mobility separations. The first part provides a critical overview of chromatography-influenced resolution equations, including refinement of existing formulae.

View Article and Find Full Text PDF

Background: Long-term viral load (VL) suppression among HIV-positive, reproductive-aged women on ART is key to eliminating mother-to-child transmission (MTCT) but few data exist from sub-Saharan Africa. We report trends in post-partum VL in Malawian women on ART and factors associated with detectable VL up to 24 months post-partum.

Methods: 1-6 months post-partum mothers, screened HIV-positive at outpatient clinics in Malawi, were enrolled (2014-2016) with their infants.

View Article and Find Full Text PDF

Background: With the global shortage of skilled health workers estimated at 7.2 million, outpatient tuberculosis (TB) care is commonly task-shifted to lay health workers (LHWs) in many low- and middle-income countries where the shortages are greatest. While shown to improve access to care and some health outcomes including TB treatment outcomes, lack of training and supervision limit the effectiveness of LHW programs.

View Article and Find Full Text PDF

Isolation of biomolecules in vacuum facilitates characterization of the intramolecular interactions that determine three-dimensional structure, but experimental quantification of conformer thermochemistry remains challenging. Infrared spectroscopy of molecules trapped in helium nanodroplets is a promising methodology for the measurement of thermochemical parameters. When molecules are captured in a helium nanodroplet, the rate of cooling to an equilibrium temperature of ca.

View Article and Find Full Text PDF

In the past decade, ion mobility spectrometry (IMS) in combination with mass spectrometry (IM-MS) became a widely employed technique for the separation and structural characterization of ionic species in the gas phase. Similarly to chromatography, where studies on the mechanism of band broadening and adequate plate-height equations have been aiding method development and promoting advancements in column technology, a suitable resolving power theory of drift tube ion mobility-mass spectrometry (DTIM-MS) is essential to stimulate further progress in this emerging field of separation science. In the present study, therefore, we explore dispersion processes in detail and present a plate-height model of ion mobility-mass spectrometry.

View Article and Find Full Text PDF

Heparan sulfate and heparin are highly acidic polysaccharides with a linear sequence, consisting of alternating glucosamine and hexuronic acid building blocks. The identity of hexuronic acid units shows a variability along their sequence, as d-glucuronic acid and its 5 epimer, l-iduronic acid, can both occur. The resulting backbone diversity represents a major challenge for an unambiguous structural assignment by mass spectrometry-based techniques.

View Article and Find Full Text PDF
Article Synopsis
  • * The study uses cryogenic vibrational spectroscopy and ion mobility-mass spectrometry to analyze B-type fragments from protected galactosides made from different glycosyl donors.
  • * Results show that the infrared signatures of these fragments indicate they have the same structure, implying that fully protected monosaccharides do not retain anomeric memory in B-type ions.
View Article and Find Full Text PDF

Background: Little is known about how to build leadership capacity to support implementation of evidence-based practices within health systems. We observed substantial variability across sites in uptake and sustainability of a peer-led educational outreach intervention for lay health workers (LHWs) providing tuberculosis care in Malawi. Feedback from peer-trainers (PTs) suggested that leadership may have contributed to the variation.

View Article and Find Full Text PDF