HIV prevalence in transgender populations and cisgender men who have sex with men in sub-Saharan Africa 2010-2022: a meta-analysis

Introduction

The Global AIDS Strategy 2021-2026 calls for equitable and equal access to HIV prevention and treatment programmes for all populations to reduce HIV incidence and end HIV/AIDS as a public health threat by 2030. Transgender populations (TGP), including transmen (TGM) and transwomen (TGW) are populations that have been marginalised and are at high risk of HIV infection in sub-Saharan Africa (SSA). Limited surveillance data on HIV among TGP are available in the region to guide programmatic responses and policymaking. Surveillance data on cisgender men who have sex with men (cis-MSM) are comparatively abundant and may be used to infer TGP HIV prevalence.

Methods

Data from key population surveys conducted in SSA between 2010-2022 were identified from existing databases and survey reports. Studies that collected HIV prevalence on both TGP and cis-MSM populations were analysed in a random effect meta-analysis to estimate the ratio of cis-MSM:TGW HIV prevalence.

Results

Eighteen studies were identified encompassing 8,052 TGW and 19,492 cis-MSM. TGW HIV prevalence ranged from 0-71.6% and cis-MSM HIV prevalence from 0.14-55.7%. HIV prevalence in TGW was 50% higher than in cis-MSM (prevalence ratio (PR) 1.50 95% CI 1.26-1.79). TGW HIV prevalence was highly correlated with year/province-matched cis-MSM HIV prevalence (R2 = 0.62), but poorly correlated with year/province-matched total population HIV prevalence (R2 = 0.1). Five TGM HIV prevalence estimates were identified ranging from 1-24%. Insufficient TGM data were available to estimate cis-MSM:TGM HIV prevalence ratios.

Conclusion

Transgender women experience a significantly greater HIV burden than cis-MSM in SSA. Bio-behavioural surveys designed and powered to measure determinants of HIV infection, treatment coverage, and risk behaviours among transgender populations, distinct from cis-MSM, will improve understanding of HIV risk and vulnerabilities among TGP and support improved programmes.

Omicron B.1.1.529 variant infections associated with severe disease are uncommon in a COVID-19 under-vaccinated, high SARS-CoV-2 seroprevalence population in Malawi

Background

The B.1.1.529 (Omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the fourth COVID-19 pandemic wave across the southern African region, including Malawi. The seroprevalence of SARS-CoV-2 antibodies and their association with epidemiological trends of hospitalisations and deaths are needed to aid locally relevant public health policy decisions.

Methods

We conducted a population-based serosurvey from December 27, 2021 to January 17, 2022, in 7 districts across Malawi to determine the seroprevalence of SARS-CoV-2 antibodies. Serum samples were tested for antibodies against SARS-CoV-2 receptor binding domain using WANTAI SARS-CoV-2 Receptor Binding Domain total antibody commercial enzyme-linked immunosorbent assay (ELISA). We also evaluated COVID-19 epidemiologic trends in Malawi, including cases, hospitalisations and deaths from April 1, 2021 through April 30, 2022, collected using the routine national COVID-19 reporting system. A multivariable logistic regression model was developed to investigate the factors associated with SARS-CoV-2 seropositivity.

Findings

Serum samples were analysed from 4619 participants (57% female; 60% aged 18-50 years), of whom 878/3794 (23%) of vaccine eligible adults had received a single dose of any COVID-19 vaccine. The overall assay-adjusted seroprevalence was 83.7% (95% confidence interval (CI), 79.3%-93.4%). Seroprevalence was lowest among children <13 years of age (66%) and highest among adults 18-50 years of age (82%). Seroprevalence was higher among vaccinated compared to unvaccinated participants (1 dose, 94% vs. 77%, adjusted odds ratio 4.89 [95% CI, 3.43-7.22]; 2 doses, 97% vs. 77%, aOR 6.62 [95% CI, 4.14-11.3]). Urban residents were more likely to be seropositive than those from rural settings (91% vs. 78%, aOR 2.76 [95% CI, 2.16-3.55]). There was at least a two-fold reduction in the proportion of hospitalisations and deaths among the reported cases in the fourth wave compared to the third wave (hospitalisations, 10.7% (95% CI, 10.2-11.3) vs. 4.86% (95% CI, 4.52-5.23), p < 0.0001; deaths, 3.48% (95% CI, 3.18-3.81) vs. 1.15% (95% CI, 1.00-1.34), p < 0.0001).

Interpretation

We report reduction in proportion of hospitalisations and deaths from SARS-CoV-2 infections during the Omicron variant dominated wave in Malawi, in the context of high SARS-CoV-2 seroprevalence and low COVID-19 vaccination coverage. These findings suggest that COVID-19 vaccination policy in high seroprevalence settings may need to be amended from mass campaigns to targeted vaccination of reported at-risk populations.

Funding

Supported by the Bill and Melinda Gates Foundation (INV-039481).

Time-dependent behaviour of bone accentuates loosening in the fixation of fractures using bone-screw systems

Aims

Loosening is a well-known complication in the fixation of fractures using devices such as locking plates or unilateral fixators. It is believed that high strains in the bone at the bone-screw interface can initiate loosening, which can result in infection, and further loosening. Here, we present a new theory of loosening of implants. The time-dependent response of bone subjected to loads results in interfacial deformations in the bone which accumulate with cyclical loading and thus accentuates loosening.

Methods

We used an 'ideal' bone-screw system, in which the screw is subjected to cyclical lateral loads and trabecular bone is modelled as non-linear viscoelastic and non-linear viscoelastic-viscoplastic material, based on recent experiments, which we conducted.

Results

We found that the interfacial deformation in the bone increases with the number of cycles, and the use of a non-linear viscoelastic-viscoplastic model results in larger deformations, some of which are irrecoverable. There is an apparent trend in which interfacial deformations increase with increasing porosity of bone.

Conclusion

The developed time-dependent model of the mechanical behaviour of bone permits prediction of loosening due to cyclical loads, which has not been possible previously. Application of this model shows that implant loosening will be accentuated by cyclical loading due to physiological activities, and the risks of loosening are greater in osteoporotic patients.Cite this article: S. Xie, K. Manda, P. Pankaj. Time-dependent behaviour of bone accentuates loosening in the fixation of fractures using bone-screw systems. Bone Joint Res 2018;7:580-586. DOI: 10.1302/2046-3758.710.BJR-2018-0085.R1.

Radiosensitizing effect of epothilone B on human epithelial cancer cells

BACKGROUND

A combined modality treatment employing radiation and chemotherapy plays a central role in the management of solid tumors. In our study, we examined the cytotoxic and radiosensitive effect of the microtubule stabilizer epothilone B on two human epithelial tumor cell lines in vitro and its influence on the microtubule assembly.

METHODS

Cancer cells were treated with epothilone B in proliferation assays and in combination with radiation in colony-forming assays. For the analysis of ionizing radiation-induced DNA damage and the influence of the drug on its repair a γH2AX foci assay was used. To determine the effect of epothilone B on the microtubule assembly in cells and on purified tubulin, immunofluorescence staining and tubulin polymerization assay, respectively, were conducted.

RESULTS

Epothilone B induced a concentration- and application-dependent antiproliferative effect on the cells, with IC(50) values in the low nanomolar range. Colony forming assays showed a synergistic radiosensitive effect on both cell lines which was dependent on incubation time and applied concentration of epothilone B. The γH2AX assays demonstrated that ionizing radiation combined with the drug resulted in a concentration-dependent increase in the number of double-strand breaks and suggested a reduction in DNA repair capacity. Epothilone B produced enhanced microtubule bundling and abnormal spindle formation as revealed by immunofluorescence microscopy and caused microtubule formation from purified tubulin.

CONCLUSION

The results of this study showed that epothilone B displays cytotoxic antitumor activity at low nanomolar concentrations and also enhances the radiation response in the tumor cells tested; this may be induced by a reduced DNA repair capacity triggered by epothilone B. It was also demonstrated that epothilone B in fact targets microtubules in a more effective manner than paclitaxel.

Laccase-catalyzed carbon-nitrogen bond formation: coupling and derivatization of unprotected L-phenylalanine with different para-hydroquinones

Unprotected L-phenylalanine was derivatized by an innovative enzymatic method by means of laccases from Pycnoporus cinnabarinus and Myceliophthora thermophila. During the incubation of L-phenylalanine with para-hydroquinones using laccase as biocatalyst, one or two main products were formed. Dependent on the substitution grade of the hydroquinones mono- and diaminated products were detected. Differences of the used laccases are discussed. The described reactions are of interest for the derivatization of amino acids and a synthesis of pharmacological-active amino acid structures in the field of white biotechnology.

α-Lipoic acid attenuates x-irradiation-induced oxidative stress in mice

The development of nontoxic but effective radioprotectors is needed because of the increasing risk of human exposure to ionizing radiation. We have reported that alpha-lipoic acid confers considerable radio-protective effect in mouse tissues when given prior to x-irradiation. In the present study, alpha-lipoic acid supplementation prior to x-irradiation with 4 and 6 Gy significantly inhibited the radiation-induced decline in total antioxidant capacity (TAC) of plasma. Radiation-induced decline in non-protein sulfhydryl content (NPSH) of different tissues, namely, brain, liver, spleen, kidney, and testis, was also ameliorated significantly at both 4 and 6 Gy doses. Maximal augmentation of radiation-induced protein carbonyl content was observed in spleen followed by brain, kidney, testis, and liver. Maximal protection in terms of carbonyl content was observed in spleen (116%) at 6 Gy dose, and minimal protection was found in liver (22.94%) at 4 Gy dose. Maximal increase in MDA (malondialdehyde) content was observed in brain, followed by testis, spleen, kidney, and liver. Protection by alpha-lipoic acid pretreatment in terms of MDA content was maximal in brain (51.67%) and minimal in spleen. The findings support the idea that alpha-lipoic acid is a free-radical scavenger and a potent antioxidant.

Laccase-induced derivatization of unprotected amino acid L-tryptophan by coupling with p-hydroquinone 2,5-dihydroxy-N-(2-hydroxyethyl)-benzamide

We have studied the enzymatic derivatization of amino acids by use of the polyphenol oxidase laccase. Derivatization of L-tryptophan was achieved by enzymatic crosslinking with the laccase substrate 2,5-dihydroxy-N-(2-hydroxyethyl)-benzamide. The main product (yield up to 70%) was identified as the quinoid compound 2-[2-(2-hydroxy-ethylcarbamoyl)-3,6-dioxo-cyclohexa-1,4-dienylamino]-3-(1H-indol-3-yl)- propionic acid and demonstrates that laccase-catalyzed C-N-coupling occurred on the amino group of the aliphatic side chain. These enzyme based reactions provide a simple and fast method for the derivatization of unprotected amino acids.

Epidemiology of humeral fractures in Malawi

We analysed and determined retrospectively the location, age, gender and side of the body of humeral fractures from 258 antero-posterior radiographs of all patients aged 3-81 years over a 5-year period. It was observed that 160 fractures occurred on the left side while 98 were on the right side with 156 occurring in males and 102 in females. Forty-eight percent of the fractures occurred at the lower end of the humerus while 41% occurred at the mid-shaft with only 10% occurring at the upper end. Furthermore, the age group of 3-12 years had the highest incidence of fractures (40.7%) with the age group of 30-39 years the lowest incidence (6.2%). Most supracondylar fractures (75.4%) occurred in children, with teenagers accounting for the majority of mid-shaft fractures (51.9%). However, middle-aged and elderly individuals had the highest incidence of upper humeral fractures (73.1%). There was significant relationship between the site of these fractures, age, gender and body side of the patients studied (p<0.001). These results are, however, not in agreement with some previously documented studies. The importance of epidemiological study of humeral fractures in planning, training and resource management in a given population is therefore stressed.

Melatonin-induced reduction in age-related accumulation of oxidative damage in mice

The ever-increasing understanding of oxygen radical-linked diseases, including the biological process of aging, has stimulated general interest in modulating these biological events. Melatonin has been reported to have antioxidant properties in addition to its known hormonal activities. However, reports on low-level chronic administration with its anti-aging influence are scanty. Hence, the present study was aimed to investigate the influence of low-dose chronic administration (0.10 mg/kg body weight/day for 3 months) of melatonin against age-induced oxidative stress in mice tissues, namely brain, liver, spleen and kidney. Sixteen-month-old mice were supplemented with melatonin (0.10 mg/kg body weight/day) for three months and then autopsied (at the age of 19 months) for the biochemical estimation of lipid peroxidation, reduced glutathione (GSH), glutathione disulphide (GSSG), glutathione peroxidase (GSH-Px) and serum phosphatase activity. Results indicate that age-induced augmentation (compared to 6-8-week-old mice) in the level of lipid peroxidation, GSSG and acid phosphatase is significantly (P < 0.001) ameliorated in melatonin-treated mice. Age-induced decline in the level of GSH, GSH-Px and alkaline phosphatase activity is inhibited significantly by the long-term administration of melatonin. The findings indicate that low-dose chronic administration of melatonin acts as a free radical scavenger and anti-aging agent.

Prophylactic action of melatonin against cyclophosphamide-induced oxidative stress in mice

The present study investigated the prophylactic influence of melatonin against cyclophosphamide-induced oxidative stress in mouse tissues. Lipid peroxidation, reduced glutathione (GSH), glutathione disulphide (GSSG), glutathione peroxidase (GSH-Px) and serum phosphatase levels were analyzed in brain, spleen liver, lungs, kidney and testes. Fifteen days oral administration with melatonin (0.1 mg/kg bw per day) before treatment checked the augmentation of the level of lipid peroxidation, blood GSSG and acid phosphatase caused by an acute treatment with a radiomimetic drug, cyclophosphamide (75 mg/kg bw). Cyclophosphamide-induced depletion in the level of GSH, GSH-Px and alkaline phosphatase was made up statistically significant by chronic melatonin administration given orally. The results indicate the antioxidative properties of melatonin resulting into its prophylactic property against the cyclophosphamide-induced biochemical alterations. The finding support the idea that melatonin is a potent free-radical scavenger and antioxidant.

Pre-administration of beta-carotene protects tissue glutathione and lipid peroxidation status following exposure to gamma radiation

The present study has been aimed to investigate the protective effect of beta-carotene against radiation-induced oxidative stress in mice tissues using lipid peroxidation and glutathione (GSH) as end points. Fourteen days oral priming administration of beta-carotene (35 mg/kg body weight) followed by an acute dose of gamma radiation (5 Gy) inhibited the augmented level of thiobarbituric acid reactive substance (TBARS) and a statistically significant protection against GSH depletion. Results evaluated from this study clearly indicate the antioxidative property of beta-carotene against gamma radiation, which is suggestive of free radical scavenging and singlet oxygen quenching.