Nine-Month Trend of IgG Antibody Persistence and Associated Symptoms Post-SARS-CoV-2 Infection.

Between 2 and 8.5% of patients who recover from COVID-19 do not develop antibodies, and the durability of IgG antibodies is under scrutiny. Therefore, the presence and persistence of IgM and IgG antibodies were evaluated in a group of patients diagnosed with SARS-CoV-2 from May to August 2020. Out of 2199 suspected COVID-19 cases, 1264 were confirmed for SARS-CoV-2 by rRT-PCR; 328 consented to participate in the study, with 220 participants followed for 9 months, including 124 men (56%) and 96 women (44%). The primary symptoms were headache, dry cough, and fever. IgG antibodies developed in 95% of patients within 4 weeks post-diagnosis, and a second evaluation at 9 months showed that 72.7% still had detectable IgG antibodies. The presence of IgM in one individual (0.45%) suggested the possibility of reinfection.

Sex-Specific Association between Fasting Plasma Glucose and Serum Selenium Levels in Adults from Southern Mexico.

Selenium (Se) is an essential trace element that by its antioxidant properties has been studied to elucidate its participation in the development of obesity and type 2 diabetes. We evaluated the association between cardiometabolic traits and serum Se levels in a sample of adults from southern Mexico. In 96 nondiabetic individuals, anthropometric data and clinical biochemistry measurements were analyzed. Serum total Se levels were measured with inductively coupled plasma mass spectrometry (ICP-MS). Serum Se level in the whole sample was 10.309 ± 3.031 µg mL-1 and no difference between the women and men was observed (p = 0.09). Additionally, fasting plasma glucose (FPG) was significantly associated with serum Se level (ß = -0.07 ± 0.03, p = 0.02, analysis adjusted for age, sex and BMI). Furthermore, sex shows significant interaction with FPG on the serum Se levels (p = 0.01). A follow-up analysis revealed the particular association between FPG and Se levels in women (ß = -0.10 ± 0.04, p = 0.01). In conclusion, our data evidenced a women-specific association between FPG and serum Se levels in a sample of adults from southern Mexico.

Serum zinc levels are associated with obesity and low-density lipoprotein cholesterol in Mexican adults.

PURPOSE: Little is known about the association between serum zinc (Zn) levels and obesity in the Mexican population. Therefore, we tested the association between serum Zn levels, obesity status, and serum lipid levels in a sample of Mexican adults. METHODS: Anthropometric data and serum levels of total cholesterol, high- and low-density lipoprotein cholesterol (HDL-C and LDL-C, respectively), and triglycerides were analyzed in 96 Mexican adults. Serum Zn was measured with inductively coupled plasma mass spectrometry. An individual data meta-analysis of the association between serum Zn, overweight, and obesity status was performed in 172 adults from two different provinces in Mexico. RESULTS: Serum Zn was negatively associated with body mass index (BMI, ß = -0.034 ± 0.013, p = 2.0 ×10-6) and obesity (odds ratio [OR]= 0.990, 95% confidence interval [CI]= 0.980-0.999, p = 3.4 ×10-5). The association between Zn level and obesity in Mexican adults was confirmed with an individual data meta-analysis (OR= 0.977, 95% CI= 0.966-0.988, p = 3.4 ×10-5). In addition, a significant interaction effect between serum Zn level and sex was observed on LDL-C level (ß = 7.010 ± 3.295, p = 0.037). Serum Zn was negatively associated with LDL-C levels in women (ß = -0.188 ± 0.074, p = 0.016). CONCLUSION: Our results confirm the negative association of serum Zn level with obesity. For the first time, we show a sex-specific association between serum Zn and LDL-C levels in a Mexican population. However, further studies are needed in larger and more varied Mexican cohorts to replicate and confirm our findings.

Correlation of HOMA-IR with BMI-for-age percentile in children and adolescents from the Soconusco region of Chiapas, Mexico / Correlación del HOMA-IR con el índice de masa corporal percentil en niños y adolescentes de la región Soconusco de Chiapas, México

Abstract Introduction: Insulin resistance (IR) is a major risk factor for developing diabetes mellitus type 2 and cardiovascular diseases. In pediatrics, morbidity and mortality associated with these diseases highlights the diagnostic importance of IR for primary care. Objective: To determine Homeostatic Model Assessment Insulin Resistance (HOMA-IR) values and their correlation with BMI-for-age percentile in children and adolescents of the Soconusco region of Chiapas, Mexico. Materials and methods: Cross-sectional study. Overweight and obesity prevalence was determined based on the Body Mass Index (BMI) percentile of112 children (5-19 years old). Glucose and fasting insulin values were quantified and used for estimation of HOMA-IR. Results: The combined prevalence of obesity and overweight was 66%, with insulin (p=0.010) and HOMA-IR (p=0.015) values higher than those of the normal weight group. The HOMA-IR values correlated positively with age (r=0.636), weight (r=0.569), height (r=0.578) and BMI percentile (r=0.198). Conclusions: In the study population, HOMA-IR has a moderately significant correlation with an increase in BMI percentile.

Resumen Introducción. La resistencia a la insulina es un factor importante en el desarrollo de diabetes mellitus tipo 2 y de enfermedades cardiovasculares. En pediatría, su morbimortalidad resalta la importancia diagnóstica con fines de atención primaria. Objetivo. Determinar los valores del homeostatic model assessment insulin resistance (HOMA-IR) y su relación con el índice de masa corporal percentil (IMCp) en niños y adolescentes de la región Soconusco, Chiapas. Materiales y métodos. Estudio transversal. Se determinó sobrepeso y obesidad por IMCp en 112 pacientes pediátricos (5-19 años); se determinaron concentraciones de glucosa y de insulina sérica para estimar el HOMA-IR. Resultados. Se encontró una prevalencia combinada de obesidad y sobrepeso de 66% con valores de insulina (p=0.010) y de HOMA-IR (p=0.015) más elevados que los del grupo de peso normal. El HOMA-IR se correlacionó positivamente con la edad (r=0.636), el peso (r=0.569), la talla (r=0.578) y el IMCp (r=0.198). Conclusión. En la población de estudio, el HOMA-IR presenta una correlación moderadamente significativa con el aumento del IMCp.

The +1858 C/T Polymorphism in the PTPN22 Gene Is Associated with Cystic Fibrosis Patients in Northeast Mexico.

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population, but it has also been widely diagnosed in the Mexican population. Production of viscous secretions affects the secretory epithelia and the respiratory condition usually leads to death. The relationship between the CFTR genotype and the disease phenotype is not well understood. Other risk factors such as genetic and autoimmune influence the development of this disease. We analyzed the PTPN22 R620W polymorphism (+1858 C/T, rs2476601) in 78 DNA samples from CF patients and 232 healthy controls from northeast Mexico using the polymerase chain reaction-restriction fragment length (PCR-RFLP) method. The C allele and the CC genotype were the most frequently detected in controls (CC genotype 96.12%; C allele 98.06%) compared with CF patients (CC genotype 88.46%, C allele 93.59%). A statistically significant association for the CT + TT genotypes (p = 0.012, OR = 3.232) as well as for the mutant T allele (p = 0.005, OR = 3.463) was found when comparing CF patients with controls. A significant association was found between the rs2476601 polymorphism of the PTPN22 gene and CF in Mexican patients. Further studies are necessary to understand the influence of this variant on lung neutrophil function and disease development.

A PCR-RFLP method for typing human papillomavirus type 16 variants.

Infection with some types of human papillomavirus (HPV) is required for cervical cancer development, being HPV type 16 (HPV 16) the most common type in premalignant and malignant cervical lesions. DNA sequencing has revealed the existence of intratypic variants of HPV 16 whose genotyping is clinically useful for distinguishing between persistent and recurrent infections. From the epidemiological perspective, the frequency of diverse HPV 16 variants in several populations could correlate with the presence of precursor high-risk lesions in different anatomical locations. Currently, the "gold standard" method for identifying HPV 16 variants involves the sequencing of genomic regions to identify characteristic polymorphic sites. Although some other methods have been described, they require specialized or high-cost equipment. In this study, a robust and low cost procedure is described for HPV 16 variant typing, based on the long control region of the virus.

Análisis preliminar de la actividad antimicrobiana de la planta medicinal Chik chawa (Tagetes nelsonii Greenm) / Preliminary analysis of antimicrobial activity of medicinal plant Chik chawa (Tagetes nelsonii Greenm)

INTRODUCCIÓN: Tagetes nelsonii Greenm., comúnmente llamada Chik chawa, es una planta utilizada en San Cristóbal de las Casas, Chiapas, México, porque los indígenas de esa región la han utilizado de manera tradicional para el tratamiento empírico de las diarreas, dolor de cabeza y fiebre; por lo cual los pobladores la han adoptado como una planta medicinal. OBJETIVO: determinar la actividad antimicrobiana in vitro de extractos de T. nelsonii. MÉTODOS: se prepararon 3 diferentes extractos, hexánico, metanólico y diclorometánico, de follaje de T. nelsonii, así como también infusión, los cuales fueron probados frente a 7 diferentes cepas microbianas por el método de dilución en placa de agar. A los extractos activos se les determinó la concentración mínima inhibitoria frente a las cepas microbianas que fueron susceptibles y las concentraciones mínimas bactericidas se determinaron mediante el método de dilución en caldo.RESULTADOS: 4 de las 7 cepas estudiadas fueron sensibles, estas fueron P. mirabilis al extracto metanólico, S. aureus y P. aeruginosa (ATCC 27863) a los extractos metanólico, hexánico y diclorometánico y C. albicans al extracto diclorometánico. La infusión de chik chawa no mostró actividad antimicrobiana. El extracto metanólico frente a P. mirabilis y S. aureus mostró efecto bactericida. CONCLUSIONES: los extractos orgánicos de Chik chawa mostraron actividad antimicrobiana sobre cepas bacterianas asociadas comúnmente con enfermedades humanas. Ninguno de los extractos causó efecto antifúngico. Se necesitan otros estudios para dilucidar los principios activos responsables de la actividad antibacteriana en los extractos probados.

INTRODUCTION: Tagetes nelsonii Greenm, usually called Chik chawa, is a plant used in San Cristobal de las Casas, Chiapas, México, because of natives from that region used it in a traditional way for empirical treatment of diarrheas, headache and fever, which has been adopted as a medicinal plant.OBJECTIVE: to determine the in vitro antimicrobial activity of T. nelsonii extracts. METHODS: three extracts were prepared: hexanic, methanolic and dichloromethanic from the T. nelsonii foliage, as well as a infusion, which were assayed versus 7 different microbial strains by agar plate diffusion method. In active extracts the inhibitory minimal concentration were determined versus susceptible microbial strains and the bactericidal minimal concentrations were determined by broth dilution method. RESULTS: four of the 7 study strains were sensible including P. mirabilis to methanolic extract, S. aureus and P. aeruginosa (ATCC 27863) to methanolic, hexanic and dichloromethanic extracts, and C. albicans to dichloromethanic extract. Chik chawa infussion has not antimicrobial activity. CONCLUSIONS: methanolic extract versus P. mirabilis y S. aureus showed this kind of activity on bacterial strains commonly associated with human diseases. Other studies are necessary to elucidate the active principles accounting for the antibacterial activity in the assayed extracts.

Expression of Nocardia brasiliensis superoxide dismutase during the early infection of murine peritoneal macrophages.

Nocardia brasiliensis is the main agent of actinomycetoma in Mexico, but little is known about its virulence and molecular pathogenic pathways. These facultative intracellular bacteria are able to survive and divide within the host phagocytic cells, in part by neutralizing the reactive oxygen intermediates. Superoxide dismutase (SOD) participates in the intracellular survival of several bacterial species and, in particular, constitutes one of Nocardia asteroides virulence factors. To clarify SOD participation in the N. brasiliensis early infective process, we report its isolation and the consequent comparison of its transcript level. A 630 bp polymerase chain reaction fragment that included most of the coding sequence of N. brasiliensis sodA was cloned. A competitive assay was developed, allowing comparison of bacterial sod expression in exponential culture and 1 h after infecting peritoneal macrophages from BALB/c mice. At that time, there were viable bacteria in the macrophages. The intracellular bacteria presented a clear decrease in their sod transcript amount, although their 16S rRNA (used as an internal control) and hsp levels were maintained or slightly increased, respectively. These results indicate that sodA transcription is not maintained within the SOS bacterial response induced by phagosomal conditions. Further kinetics will be necessary to precisely define sod transcriptional regulation during N. brasiliensis intra-macrophage growth.