Comparative cytogenetics in three Melipona species (Hymenoptera: Apidae) with two divergent heterochromatic patterns.

The genus Melipona is subdivided into four subgenera based on morphological characteristics, and two groups based on cytogenetic patterns. The cytogenetic information on this genus is still scarce, therefore, the goal of this study was to characterize Melipona paraensis, Melipona puncticollis, and Melipona seminigra pernigra using the following techniques: C-banding, DAPI/CMA3 fluorochromes, and FISH with an 18S rDNA probe. Melipona paraensis (2n=18) and M. seminigra pernigra (2n=22) were classified as high heterochromatin content species (Group II). Their euchromatin is restricted to the ends of the chromosomes and is CMA3+; the 18S rDNA probe marked chromosome pair number 4. Melipona puncticollis (2n=18) is a low heterochromatin content species (Group I) with chromosome pair number 1 marked with CMA3 and 18S rDNA. Low heterochromatin content is a putative ancestral karyotype in this genus and high content is not a monophyletic trait (Melikerria presents species with both patterns). Differences concerning the karyotypic characteristics can be observed among Melipona species, revealing cytogenetic rearrangements that occurred during the evolution of this genus. Studies in other species will allow us to better understand the processes that shaped the chromatin evolution in Melipona.

HIV-1 diversity and pre-treatment drug resistance in the era of integrase inhibitor among newly diagnosed ART-naïve adult patients in Luanda, Angola.

The surveillance of drug resistance in the HIV-1 naïve population remains critical to optimizing the effectiveness of antiretroviral therapy (ART), mainly in the era of integrase strand transfer inhibitor (INSTI) regimens. Currently, there is no data regarding resistance to INSTI in Angola since Dolutegravir-DTG was included in the first-line ART regimen. Herein, we investigated the HIV-1 genetic diversity and pretreatment drug resistance (PDR) profile against nucleoside/tide reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and INSTIs, using a next-generation sequencing (NGS) approach with MinION, established to track and survey DRMs in Angola. This was a cross-sectional study comprising 48 newly HIV-diagnosed patients from Luanda, Angola, screened between March 2022 and May 2023. PR, RT, and IN fragments were sequenced for drug resistance and molecular transmission cluster analysis. A total of 45 out of the 48 plasma samples were successfully sequenced. Of these, 10/45 (22.2%) presented PDR to PIs/NRTIs/NNRTIs. Major mutations for NRTIs (2.2%), NNRTIs (20%), PIs (2.2%), and accessory mutations against INSTIs (13.3%) were detected. No major mutations against INSTIs were detected. M41L (2%) and I85V (2%) mutations were detected for NRTI and PI, respectively. K103N (7%), Y181C (7%), and K101E (7%) mutations were frequently observed in NNRTI. The L74M (9%) accessory mutation was frequently observed in the INSTI class. HIV-1 pure subtypes C (33%), F1 (17%), G (15%), A1 (10%), H (6%), and D (4%), CRF01_AG (4%) were observed, while about 10% were recombinant strains. About 31% of detected HIV-1C sequences were in clusters, suggesting small-scale local transmission chains. No major mutations against integrase inhibitors were detected, supporting the continued use of INSTI in the country. Further studies assessing the HIV-1 epidemiology in the era of INSTI-based ART regimens are needed in Angola.

Immune profile of healthcare professionals six months after vaccination or exposure to SARS-CoV-2 in Angola.

Background and Aims: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a public health concern. Until 2021, more than 2 million cumulative deaths were reported worldwide. Herein, we investigated the immune profile of healthcare professionals 6 months after vaccination or exposure to SARS-CoV-2 in Angola. Methods: This was a prospective study conducted with 1068 Angolan healthcare professionals between August and December 2021. Participants were screened for the presence of IgG and IgM against SARS-CoV-2. Results: About 9.6% and 98.2% of the participants had prior exposure to SARS-CoV-2 or vaccination against it, respectively. Participants aged between 20 and 40 years (11.2%), female (12.4%), with higher educational level (12.8%), from Luanda (60.3%), and nonhealthcare professionals (8.1%) were the most affected by the SARS-CoV-2. Gender, education, and local residence were related to SARS-CoV-2 exposure (p < 0.05). About 7.3% and 98% of the exposed population developed IgM and IgG after 3 months of exposure, respectively. The AstraZeneca vaccine was the most used, followed by the Jonhson & Johnson and Sputinik. Almost all (98%) participants vaccinated with AstraZeneca had immunity >3 months. Individuals who received only the first dose regardless of the type of vaccine had a higher immunity duration (>3 months) than those who received two doses. For individuals who received the Sputnik and Johnson, the average immunity was lower (<3 months), especially among those who were older (over 40 years old) and exposed to SARS-CoV-2. Conclusion: We observed a high adherence rate to vaccination and a long immunity duration. The immunity duration depended on the type of vaccine. Further studies on the immunity profile in the population exposed to SARS-CoV-2 must be carried out in the general population from Angola to assess antibody-waning periods.

Demographic characteristics and risk factors related to high blood pressure among healthy blood donors from Luanda, Angola: A retrospective study.

Background and Aims: Hypertension is a public health concern, mainly in resource-limited countries. We investigated the characteristics and risk factors related to high blood pressure in healthy blood donors from, Luanda, the capital city of Angola. Methods: This was a retrospective study that included 343 healthy donors from December 2019 to September 2020. Results: The mean age was 32 ± 9 years. Men represented 93% of the population. Mean systolic blood pressure (SBP) was 131 ± 12.3 mmHg (ranging from 100 to 160 mmHg) and diastolic blood pressure (DBP) was 80.1 ± 9.72 mmHg (from 56.0 to 100 mmHg). DBP was related to age and gender (p < 0.05). About 7.3% of the donors had high-pressure (>140/90 mmHg). Age between 20 and 40 years (odds ratio [OR]: 2.52, p = 0.043), women (OR: 1.87, p = 0.548), nonurbanized areas (OR: 0.39, p = 0.067), high educational level (OR: 0.76, p = 0.637), employed (OR: 0.49, p = 0.491), voluntary donors (OR: 0.87, p = 0.799), blood group B (OR: 2.06, p = 0.346), and Rh- (OR: 0.26, p = 0.104), were potentially related with high-pressure. The high-pressure cases increased from December 2019 (4%) to September 2020 (28%) (p = 0.019). Conclusion: We showed high pressure among the healthy blood donors population. Demographic characteristics, ABO/Rh blood group, and year period are features that should be considered in cardiovascular disease control strategies. Biological and nonbiological features related to blood pressure changes should be considered for further studies in the Angolan population.

Blood pressure pattern among blood donors exposed to SARS-CoV-2 in Luanda, Angola: A retrospective study.

Background and Aims: SARS-CoV-2 infection is a public health concern. Several aspects related to the pattern of infection remain unclear. This study aimed to investigate the blood pressure pattern among blood donors exposed to SARS-CoV-2 in Luanda, Angola, a sub-Saharan African country. Methods: We performed a retrospective analysis containing 343 blood donors from December 2019 to September 2020. Parametric tests compared means while χ 2 and logistic regression checked features associated with high blood pressure and were considered significant when p < 0.05. Results: The mean age of blood donors was 32.2 ± 8.81 years (ranging from 18 to 61 years) and 93% of the men's gender. Overall, 4.7% of the studied population had been exposed to SARS-CoV-2. High blood pressure prevalence increased from unexposed to exposed SARS-CoV-2 (6.7%-18.8%, p = 0.071). SARS-CoV-2 exposure increase systole (131 ± 12.2 mmHg to 136 ± 14.2 mmHg, p = 0.098), diastole (79.9 ± 9.53 mmHg to 84.2 ± 12.7 mmHg, p = 0.086), pulse in beats per minute (72.0 ± 11.1 to 73.7 ± 8.50, p = 0.553), and decrease donating time (6.31 ± 3.72 min to 5.48 ± 1.61 min, p = 0.371). Chances of having high blood pressure were high [OR: 3.20 (95% confidence interval [CI]: 0.85-12.1), p = 0.086] in exposed SARS-CoV-2. Donors exposed to SARS-CoV-2 with abnormal donation time increased from the donor up to 40 years to over 40 years (from 35.7% to 50%, p = 0.696). The mean systolic, diastolic, and pulse pressure were higher for non-O donors (p > 0.05). A significant link was observed, between the Rhesus factor and blood pressure status (p = 0.032). Conclusion: We showed important variations in blood pressure indices of the Angolan population exposed to SARS-CoV-2. Older age and non-O blood groups appear to be important biological factors for SARS-CoV-2 infection, as well as the risk of developing cardiovascular disease after or during SARS-CoV-2 exposure. Further studies assessing the impact on cardiovascular functions with ongoing or long-term SARS-CoV-2 exposure in individuals from resource-limited countries should be considered.

Rab5C enhances resistance to ionizing radiation in rectal cancer.

Rectal cancer represents one third of the colorectal cancers that are diagnosed. Neoadjuvant chemoradiation is a well-established protocol for rectal cancer treatment reducing the risk of local recurrence. However, a pathologic complete response is only achieved in 10-40% of cases and the mechanisms associated with resistance are poorly understood. To identify potential targets for preventing therapy resistance, a proteomic analysis of biopsy specimens collected from stage II and III rectal adenocarcinoma patients before neoadjuvant treatment was performed and compared with residual tumor tissues removed by surgery after neoadjuvant therapy. Three proteins, Ku70, Ku80, and Rab5C, exhibited a significant increase in expression after chemoradiation. To better understand the role of these proteins in therapy resistance, a rectal adenocarcinoma cell line was irradiated to generate a radiotherapy-resistant lineage. These cells overexpressed the same three proteins identified in the tissue samples. Furthermore, radiotherapy resistance in this in vitro model was found to involve modulation of epidermal growth factor receptor (EGFR) internalization by Rab5C in response to irradiation, affecting expression of the DNA repair proteins, Ku70 and Ku80, and cell resistance. Taken together, these findings indicate that EGFR and Rab5C are potential targets for the sensitization of rectal cancer cells and they should be further investigated. KEY MESSAGES: • Rab5C orchestrates a mechanism of radioresistance in rectal adenocarcinoma cell. • Rab5C modulates EGFR internalization and its relocalization to the nucleus. • In the nucleus, EGFR can modulate the expression of the DNA repair proteins, Ku70 and Ku80. • Rab5C, Ku70, and Ku80 are overexpressed in tumor tissues that contain tumor cells that are resistant to chemoradiation treatment.

Fatores associados ao baixo apgar em recém-nascidos angolanos / Factors associated with low apgar in angolan newborn / Factores asociados con apgar bajo en recién nacidos angolanos

Objetivo:avaliar os fatores associados ao baixo Apgar em recém-nascidos de Angola. Método:estudo analíticoe transversal, quali-quantitativo, em umHospital Geral de Luanda, Angola, entre março e maio de 2021. Realizou-se entrevistas em sala de observação e consulta aos prontuários das parturientes. Os dados foram analisados pelo teste qui-quadrado (X2) e regressão logística. Resultados:prevaleceu parturientes entre 19-35 anos (70,0%), 7º-9º ano (57,5%), multíparas (75%), multigestas (75,0%), sem histórico de aborto (72,5%), idade gestacional de 40 semanas (60,0%), usuárias de bebidas alcoólicas (77,5%), baixa frequência de consultas pré-natais (52,5%), com parto natural (82,5%) e recém-nascidos com peso normal (52,5%). Mulheres de região periurbana [OR:6,85 (95% CI:0.65-71,2), p=0,108] e rural [OR:4,47 (95% CI:0.47-48,4), p=0,184] apresentaram maior chance de terem recém-nascidos com baixo Apgar, assim como as usuárias de álcool [OR:3,28 (95% CI:0,58-18,3), p=0,176] e recém-nascidos que nasceram com peso normal [OR:1,75 (95% CI:0,49­6,22), p=0,387]. Não houve associação estatística entre os dados sociodemográficos e maternos. Conclusão:a faixa etária, local de residência, consumo de álcool materno e peso do recém-nascido podem implicar em baixo Apgar.

Objective: to evaluate the factors associated with low Apgar in newborns in Angola. Method:analytical and cross-sectional, quali-quantitative study, in a General Hospital in Luanda, Angola, between March and May 2021. Interviews were carried out in an observation room and consultation of the parturients' medical records. Data were analyzed using the chi-square test (X2) and logistic regression.Results: pregnant women aged 19-35 years (70.0%), 7th-9th year(57.5%), multiparous (75%), multiparous (75.0%), without a history of abortion (72.5%), prevailed. gestational age of 40 weeks (60.0%), users of alcoholic beverages (77.5%), low frequency of prenatal consultations (52.5%), with natural childbirth (82.5%) and newborns with normal weight (52.5%). Women from peri-urban regions [OR:6.85 (95% CI:0.65-71.2), p=0.108] and rural [OR:4.47 (95% CI:0.47-48.4), p=0.184] were more likely to have low Apgar newborns, as well as alcohol users [OR:3.28 (95% CI:0.58-18.3), p=0.176] and newborns who were born with normal [OR:1.75 (95% CI:0.49­6.22), p=0.387]. There was no statistical association between sociodemographic and maternal data.Conclusion: age group, place of residence, maternal alcohol consumption and newborn weight may imply low Apgar.

Objetivo: evaluar los factores asociados al Apgar bajo en recién nacidos en Angola.Método: estudio analítico y transversal, cuali-cuantitativo, en un Hospital General de Luanda, Angola, entre marzo y mayo de 2021. Se realizaron entrevistas en sala de observación y consulta de las historias clínicas de las parturientas. Los datos se analizaron mediante la prueba de chi-cuadrado (X2) y regresión logística. Resultados: gestantes de 19 a 35 años (70,0%), de 7° a 9° año (57,5%), multíparas (75%), multíparas (75,0%), sin antecedente de aborto (72,5%), predominó la edad gestacional de 40 semanas (60,0%), usuarias de bebidas alcohólicas (77,5%), baja frecuencia de consultas prenatales (52,5%), con parto natural (82,5%) y recién nacidos con normopeso (52,5%). Las mujeres de regiones periurbanas [OR:6,85 (IC 95%:0,65-71,2), p=0,108] y rurales [OR:4,47 (IC 95%:0,47-48,4), p=0,184] tenían más probabilidades de tener bajo Recién nacidos Apgar, así como consumidores de alcohol [OR:3,28 (IC 95%:0,58-18,3), p=0,176] y recién nacidos que nacieron con normalidad [OR:1,75 (IC 95%:0,49-6,22), p=0,387]. No hubo asociación estadística entre datos sociodemográficos y maternos. Conclusión: el grupo de edad, el lugar de residencia, el consumo materno de alcohol y el peso del recién nacido pueden implicar un Apgar bajo.

Papel das vesículas extracelulares secretadas por adenocarcinomas gástricos na resposta ao tratamento quimioterápico / Role of extracellular vesicles secreted by gastric adenocarcinomas in response to chemotherapy

O adenocarcinoma gástrico (AdG) é a terceira causa mais comum de morte por câncer no mundo e um dos tumores com maior índice de mortalidade no Brasil. Estes tumores aparecem em terceiro lugar na incidência entre homens e em quinto nas mulheres. A quimioterapia neoadjuvante (QT) com 5-fluorouracil (5-FU) pode melhorar a ressecabilidade e a sobrevida dos pacientes com AdG, porém sua eficácia está limitada pela resistência à droga. Apenas pacientes que respondem a esta terapia com toxicidade tolerável são potencialmente beneficiados, entretanto não é possível identificar e separar clinicamente estes indivíduos. Assim, identificar marcadores preditivos de resposta para selecionar os pacientes que se beneficiariam deste tratamento é relevante. Vesículas extracelulares (VEs) são componentes secretados pelas células incluindo células tumorais, cujo conteúdo é regulado e composto por moléculas que podem ter uma miríade de funções locais e a distância. Muitas destas moléculas podem ser também usadas como biomarcadores séricos por conterem informações importantes sobre o tumor. Desta forma, este trabalho tem como objetivo identificar marcadores de resistência a 5-FU em VEs secretadas por linhagens celulares humanas de câncer gástrico e avaliar o papel das VEs na quimioresistência. Para tanto, foram geradas células de AdG derivadas da linhagem AGS, resistentes a 5-FU (rAGS_FU) de onde foram isoladas, quantificadas e caracterizadas VEs. Células rAGS-FU secretam cerca de 2 vezes mais VEs que as células parentais (AGS), entretanto a distribuição destas por tamanho é semelhante. As células rAGS_FU apresentaram maior proliferação, capacidade de formação de colônias e invasão que as células AGS. Interessantemente, as VEs provenientes de células resistentes a 5-FU, rAGS_FU, são capazes de transferir à células AGS os fenótipos de resistência ao quimioterápico bem como um aumento na capacidade de formação de colônias e invasão. As células AGS que se tornam resistentes ao tratamento não têm este fenótipo revertido pela remoção das VEs da células resistentes nem pelo tratamento com VEs de células AGS parental, indicando que o fenótipo de resistência adquirido após o tratamento é irreversível, pelo menos pelo período estudado. O conteúdo proteico das VEs das células AGS e rAGS_FU e suas respectivas VEs foi comparado por proteômica. Nessa abordagem foram identificadas 1.915 proteínas nas células e 1.638 proteínas em VEs das quais 309 proteínas eram diferencialmente expressas em células e 66 em VEs. Entre as proteínas com expressão diferencial entre as duas células e também nas suas respectivas VEs, selecionamos e validamos por western blotting a proteina fascina. Esta parece ser um potencial candidato a biomarcador de resistência a 5-FU uma vez que sua expressão é indetectável na célula AGC e suas VEs e altamente expressa nas células rAGS_FU e suas vesículas. A fascina é uma proteína do citoesqueleto com um papel chave nas interações célula-célula, adesão e motilidade celulares e é associada a agressividade tumoral. Estes dados apontam o papel das VEs nos mecanismos relacionados à resistência a 5-FU em células de AdG e sugerem que fascina possa estar associada ao mecanismo de resistência a este quimioterápico e que também seja um potencial biomarcador deste fenótipo

Gastric adenocarcinoma (GAd) is the third most common cause of cancer related death worldwide, and one of the tumors with the highest mortality rates in Brazil. In men, this cancer ranks the third most common cancer, while in women, it ranks fifth. 5-fluorouracil (5-FU) based neoadjuvant chemotherapy can improve tumor resectability and patient's survival rates. Its effectiveness however, is limited by drug resistance. Thus, an effort to identify predictive markers of response to neoadjuvant therapy and select patients who could benefit from this treatment is relevant. One such approach could be to use contents of extracellular vesicles (EVs). EVs are components secreted by cells including tumor cells, whose contents are composed of molecules that can have a myriad of local and distance functions and many of these molecules can also be used as serum biomarkers since they contain important information about the tumor. This work aims to identify 5-FU resistance markers in EVs secreted by human gastric cancer cell line and to evaluate the role of EVs in chemoresistance. GAd cells resistant to 5-FU (rAGS_FU) were generated from the AGS cell line and EVs secreted by rAGS_FU cells and parental AGS cells were isolated, quantified and characterized. Our results showed that AGS_FU cells secrete about 2 times more EVs than parental AGS cells, however their size distribution is similar. The resistant rAGS_FU cells showed higher proliferation rates, capacity of colony formation and invasion properties. Interestingly, EVs from 5-FU resistant cells, rAGS_FU, are able to transfer to the AGS cells the phenotypes of resistance to chemotherapy as well as an increase in the capacity of colony formation and invasion. AGS cells that become resistant to treatment do not have this phenotype reversed by removal of the EVs from the resistant cells or by treatment with EVs from parental AGS cells, indicating that the resistance phenotype acquired after treatment is irreversible, at least for the period studied. The protein content of the AGS and rAGS_FU cells and their respective EVs was compared by proteomics. In this approach, 1,915 proteins were identified in cells and 1,638 proteins in EVs of which 309 proteins were differentially expressed in cells and 66 in EVs. Among the proteins with differential expression between the two cells and also in their respective EVs, we selected and validated by western blotting the protein fascin. Fascin protein appears to be a potential candidate for biomarker of 5-FU resistance since its expression is undetectable in AGS cells and their EVs and highly expressed in rAGS_FU cells and their vesicles. Fascin is a cytoskeletal protein with a key role in cellcell interactions, cell adhesion and motility and is associated with tumor aggressiveness. These data point to the role of EVs in the mechanisms related to 5-FU resistance in GAd cells and suggest that fascin may be associated with the mechanism of resistance to this chemotherapeutic agent and that it is also a potential biomarker of this phenotype