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.

Molecular Characterization of Associated Pathogens in Febrile Patients during Inter-Epidemic Periods of Urban Arboviral Diseases in Tapachula Southern Mexico.

Emerging and re-emerging vector-borne infections are a global public health threat. In endemic regions, fever is the main reason for medical attention, and the etiological agent of such fever is not usually identified. In this study, non-specific febrile pathogens were molecularly characterized in serum samples from 253 patients suspected of arbovirus infection. The samples were collected in the southern border region of Mexico from April to June 2015, and February to March 2016. ZIKV, CHIKV, DENV, leptospirosis, and rickettsiosis were detected by qPCR and nested PCR to identify flavivirus and alphavirus genera. The results indicated that 71.93% of the samples were positive for CHIKV, 0.79% for ZIKV, and 0.39% for DENV, with the number positive for CHIKV increasing to 76.67% and those positive for ZIKV increasing to 15.41% under the nested PCR technique. Leptospira Kmetyi was identified for the first time in Mexico, with a prevalence of 3.16%. This is the first report of ZIKV in Mexico, as well the first detection of the virus in early 2015. In conclusion, the etiological agent of fever was determined in 94% of the analyzed samples.

Comparison of clinical characteristics of Zika and dengue symptomatic infections and other acute illnesses of unidentified origin in Mexico.

BACKGROUND: Our purpose was to provide a detailed clinical description, of symptoms and laboratory abnormalities, and temporality in patients with confirmed Zika and dengue infections, and other acute illnesses of unidentified origin (AIUO). METHODS/ PRINCIPAL FINDINGS: This was a two-year, multicenter, observational, prospective, cohort study. We collected data from patients meeting the Pan American Health Organization's modified case-definition criteria for probable Zika infection. We identified Zika, dengue chikungunya by RT-PCR in serum and urine. We compared characteristics between patients with confirmed Zika and dengue infections, Zika and AIUO, and Dengue and AIUO at baseline, Days 3,7,28 and 180 of follow-up. Most episodes (67%) consistent with the PAHO definition of probable Zika could not be confirmed as due to any flavivirus and classified as Acute Illnesses of Unidentified Origin (AIUO). Infections by Zika and dengue accounted for 8.4% and 16% of episodes. Dengue patients presented with fever, generalized non-macular rash, arthralgia, and petechiae more frequently than patients with Zika during the first 10 days of symptoms. Dengue patients presented with more laboratory abnormalities (lower neutrophils, lymphocytosis, thrombocytopenia and abnormal liver function tests), with thrombocytopenia lasting for 28 days. Zika patients had conjunctivitis, photophobia and localized macular rash more frequently than others. Few differences persisted longer than 10 days after symptoms initiation: conjunctivitis in Zika infections, and self-reported rash and petechia in dengue infections. CONCLUSIONS: Our study helps characterize the variety and duration of clinical features in patients with Zika, dengue and AIUO. The lack of diagnosis in most patients points to need for better diagnostics to assist clinicians in making specific etiologic diagnoses.

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.

Serial real-time RT-PCR and serology measurements substantially improve Zika and Dengue virus infection classification in a co-circulation area.

BACKGROUND: Real-time RT-PCR (Reverse Transcriptase Polymerase Chain Reaction) is considered the gold standard for Zika virus (ZIKV) infection diagnosis, despite its low sensitivity. Diagnosis using recommended serologic cutoffs in co-circulating Flaviviruses areas maybe inadequate due to in-vitro cross-reactivities of Flaviviruses-specific antibodies. We evaluated Zika diagnosis in symptomatic patients using serial RT-PCR and develop a classification model using serial Dengue virus (DENV) and ZIKV serologies. METHODS: A prospective longitudinal multicentric study in Southern Mexico (NCT02831699) enrolled symptomatic and non-symptomatic participants. In the classification model, true positives were symptomatic (using a modified World Health Organization/Pan American Health Organization definition) with RT-PCR positive for ZIKV or DENV. True negatives were non-symptomatic with negative RT-PCR. Serial serology measurements were used to predict disease status. RESULTS: Analyzing ZIKV and DENV RT-PCR at 3 timepoints between days 3 and 13 of symptom onset detected 25% more cases than a single RT-PCR analysis between day 0 and 6. When considering sensitivity and specificity together, the serial serology model predicted all categories of disease and negatives better than manufactures cutoffs. Their cutoffs optimized sensitivity or specificity but not both. CONCLUSIONS: We demonstrated the importance of serial RT-PCR and antibody measurements to diagnose arbovirus infection in symptomatic patients living in regions with co-circulating flaviviruses.

Clinical characterization of acute and convalescent illness of confirmed chikungunya cases from Chiapas, S. Mexico: A cross sectional study.

BACKGROUND: The emerging chikungunya virus (CHIKV), is an arbovirus causing intense outbreaks in North America. The situation in Mexico is alarming, and CHIKV threatens to spread further throughout North America. Clinical and biological features of CHIKF outbreaks in Mexico have not been well described; thus, we conducted a cross sectional study of a CHIKV outbreak in Chiapas, Southern Mexico to further characterize these features. METHODOLOGY/PRINCIPAL FINDINGS: We collected blood samples from patients suspected of having chikungunya fever (CHIKF) who presented to Clinical Hospital ISSSTE Dr. Roberto Nettel in Tapachula, Chiapas, Mexico. In addition to the clinical examination, real-time polymerase chain reaction (PCR) standardized for the Asian Chikungunya lineage and/or enzyme-linked immunosorbent assay for immunoglobulin M (IgM) were used to confirm CHIKV diagnosis. Of a total of 850 patients who presented with probably CHIKV at Hospital "Dr. Roberto Nettel", 112 probable CHIKF cases were enrolled in this study from November 2014- June 2015, of which 95 patients (84.8%) were CHIKV positive and 17 were negative (15.2%). Of these 95 CHIKV positive patients, 62 were positive by real-time reverse transcriptase PCR (+qRT-PCR); and 33 were seropositive to +IgM with a negative qRT-PCR. The most frequent symptoms reported were fever (100%), headache (82.3%), polyarthralgia (72.1%), and exanthem (82.3%). Biological abnormalities observed during CHIKV infection were lymphopenia (41.1%), leukopenia (51.6%), elevated transaminases (30.5%-46.3%) and high LDH (46.3%) and CRP (60.0%). CONCLUSION: Clinical and biological data obtained from this study is providing more useful information for benchmarking purposes with outbreaks from different parts of the world and would be helpful for better patient care and treatment.

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.

Cu/Zn superoxide dismutase (SOD1) induction is implicated in the antioxidative and antiviral activity of acetylsalicylic acid in HCV-expressing cells.

We evaluated the participation of oxidative stress in the negative regulation of hepatitis C virus (HCV)-RNA induced by acetylsalicylic acid (ASA). We used the HCV subgenomic replicon cell system that stably expresses HCV-nonstructural proteins (Huh7 HCV replicon cells) and the parental cell line. Cells were exposed to 4 mM ASA at different times (12-72 h), and pyrrolidine dithiocarbamate (PDTC) was used as an antioxidant control. Reactive oxygen species (ROS) production, oxidized protein levels, cytosolic superoxide dismutase (Cu/Zn-SOD), and glutathione peroxidase (GPx) activity were measured to evaluate oxidative stress. In addition, viral RNA and prostaglandin (PGE(2)) levels were determined. We observed that ASA treatment decreased ROS production and oxidized protein levels in a time-dependent fashion in both parental and HCV replicon cells with a greater extent in the latter. Similar results were found with PDTC exposure. Average GPx activity was decreased, whereas a striking increase was observed in average cytosolic SOD activity at 48 and 72 h in both cells exposed to ASA, compared with untreated cells. HCV replicon cells showed higher levels of Cu/Zn-SOD expression (mRNA and protein) with ASA treatment (48 and 72 h), whereas NS5A protein levels showed decreased expression. In addition, we found that inhibition of SOD1 expression reversed the effect of ASA. Interestingly, PDTC downregulated HCV-RNA expression (55%) and PGE(2) (60%) levels, imitating ASA exposure. These results suggest that ASA treatment could reduce cellular oxidative stress markers and modify Cu/Zn-SOD expression, a phenomenon that may contribute to the mechanisms involved in HCV downregulation.

Protective effect of four Mexican plants against CCl4-induced damage on the Huh7 human hepatoma cell line.

BACKGROUND: Centaurea americana, Krameria ramosissima, Juglans mollis and Turnera diffusa are used by traditional healers in the northeastern region of Mexico to protect against liver damage. However, the hepatoprotective properties of these plants have not been investigated scientifically. This study reports on the protective effects of these plants using an in vitro assay. MATERIAL AND METHODS: Extracts of plants were tested for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method. The effects of extracts from these plants on a human hepatoma cell line (Huh7) were evaluated according to cell viability and aspartate aminotransferase and malondialdehyde levels before and after exposure of the cells to carbon tetrachloride (CCl(4)). RESULTS: All extracts reduced DPPH levels by more than 50%. C. americana flower and stem/leaf extracts, the aerial part of T. diffusa, and the nut, leaf and bark of J. mollis extracts were used to assess hepatoprotective activity. The extract of the aerial part of K. ramosissima was toxic. Pretreatment of Huh7 cells with extracts from the flower of C. americana (FCA), the stem/leaf fraction of C. americana (S/LCA), the leaf of J. mollis (LJM) and the bark of J. mollis (BJM) prior to the CCl(4) challenge, protected against CCl(4)-induced liver damage, as evidenced by a significant decrease in the activity of the medium enzyme. The FCA, S/LCA, LJM and BJM extracts showed significant antilipid peroxidant effects in vitro. In conclusion, the hepatoprotective effects of the FCA, S/LCA, LJM and BJM extracts observed in this study may result from their antioxidative properties.

Genotyping of hepatitis C virus (HCV) in infected patients from Northeast Mexico.

UNLABELLED: Information about HCV genotypes in infected patients from different regions of Mexico is limited. OBJECTIVE: To determine the prevalence of HCV genotypes in a group of HCV infected patients who attended a third level Hospital in Northeast of Mexico. METHODS: Genotyping analysis was performed using the InnoLiPA-HCV genotype assay in 147 patients (65 males and 82 females, mean age 44 +/- 12 years) with positive anti-HCV antibodies and detectable HCV-RNA levels. RESULTS: Infected individuals were more likely to be female (56%). Histological data showed that 63% of the patients had chronic hepatitis, while the remainder presented cirrhosis (37%). The most frequent HCV genotype was 1 (73%). We found the following distribution: genotype 1 (2.7%), 1a (28.6%), 1b (37.4%), 1a/1b (4.1%), 2a (1.4%), 2b (8.8%), 2c (0.7%), 2a/2c (2.7%), 3 (2%), 3a (10.2%), 4 (0.7%) and 4c (0.7%). The most frequent associated risk factor was blood transfusion (72.5%). CONCLUSION: Prevalence of HCV genotypes in the Northeast of Mexico is similar to those reported previously in other Mexican regions and the most frequent risk factor continues being blood transfusion.

Acetylsalicylic acid inhibits hepatitis C virus RNA and protein expression through cyclooxygenase 2 signaling pathways.

UNLABELLED: It has been reported that salicylates (sodium salicylate and aspirin) inhibit the replication of flaviviruses, such as Japanese encephalitis virus and dengue virus. Therefore, we considered it important to test whether acetylsalicylic acid (ASA) had anti-hepatitis C virus (HCV) activity. To this end, we examined the effects of ASA on viral replication and protein expression, using an HCV subgenomic replicon cell culture system. We incubated Huh7 replicon cells with 2-8 mM ASA for different times and measured HCV-RNA and protein levels by northern blot, real-time polymerase chain reaction, and western analysis, respectively. We found that ASA had a suppressive effect on HCV-RNA and protein levels (nearly 58%). ASA-dependent inhibition of HCV expression was not mediated by the 5'-internal ribosome entry site or 3'-untranslated regions, as determined by transfection assays using bicistronic constructs containing these regulatory regions. However, we found that HCV-induced cyclooxygenase 2 (COX-2) messenger RNA and protein levels and activity and these effects were down-regulated by ASA, possibly by a nuclear factor kappa B-independent mechanism. We also observed that the ASA-dependent inhibition of viral replication was due in part to inhibition of COX-2 and activation of p38 and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2) mitogen-activated protein kinases (MAPKs). Inhibition of these kinases by SB203580 and U0126, respectively, and by short interfering RNA silencing of p38 and MEK1 MAPK prevented the antiviral effect of ASA. Taken together, our findings suggest that the anti-HCV effect of ASA in the Huh7 replicon cells is due to its inhibitory effect on COX-2 expression, which is mediated in part by the activation of MEK1/2/p38 MAPK. CONCLUSION: These findings suggest the possibility that ASA could be an excellent adjuvant in the treatment of chronic HCV infection.

Antiviral therapy: inhibition of Hepatitis C Virus expression by RNA interference directed against the NS5B region of the viral genome.

BACKGROUND: Hepatitis C virus (HCV) is a major public health problem with 170 million chronically infected people throughout the world. Currently, the only treatment available consists of a combination of pegylated interferon (INF-alpha) and ribavirin, but only half of the patients treated show a sufficient antiviral response. Thus there is a great need for the development of new treatments for HCV infections. RNA interference (RNAi) represents a new promising approach to develop effective antiviral drugs and has been extremely effective against HCV gene expression in short-term cell culture. Our aim was to determine the effect of RNAi directed against the NS5B-HCV region on HCV expression in a human hepatoma cell line that expresses HCV-subgenomic replicon (Huh7 HCV replicon cells). METHODS: We transfected Huh7 HCV replicon cells with different concentrations of RNAi (100-200 nM) targeting the NS5B region of the viral genome. 2-6 days post-transfection HCV-RNA was quantified by semiquantitative and real-time RT-PCR, and HCV NS5B protein levels were assayed by western blot. Cell viability was also quantified by MTT assay. RESULTS: Our results indicate that the NS5B-siRNAs used in this study can specifically inhibit HCV-RNA replication and protein expression (more than 90%) compared to control cells. CONCLUSIONS: Synthetic siRNA against NS5BHCV inhibited HCV replication and viral proteins levels and thereby becomes a powerful strategy to combat hepatitis C virus.

Hepatitis C virus infection among HIV-1 infected individuals from northern Mexico.

AIMS: The prevalence of hepatitis C virus (HCV) infection, risk factors and HCV genotypes in 140 HIV-1 infected individuals from northern Mexico was determined. METHODS: Hepatitis C infection was confirmed by the detection of anti-HCV antibodies and HCV-RNA in sera, and genotyping was performed by the InnoLiPA-HCV genotype assay. RESULTS: Seventeen (12.1%) out of 140 HIV-infected individuals were found to be HCV-positive. Coinfected individuals were more likely to be male (87%). The most frequent genotype was 1a (41%), followed by 1b (29.4%), 2a/c (17.6%), 2b (5.9%) and 3 (5.9%). Serum transaminase concentrations (AST and ALT) were higher in coinfected patients. Among the risk factors for coinfection: sexual transmission was the most frequently observed (men who have sex with men (MSM); 64.7% and bisexual behavior; 64.7%) followed by intravenous drug users (IVDU) (53%). There was no association of the HCV genotypes with the age and risk factors for HIV-1 and HCV infection observed in the studied patients. CONCLUSION: The results suggest that the prevalence of HIV-1/HCV coinfection in Mexico is lower than in other American countries.

Experimental models for hepatitis C virus (HCV): new opportunities for combating hepatitis C.

Infection with hepatitis C virus (HCV) is a global public health issue. More than 200 million people in the world are infected with HCV. Hepatitis C is considered one of the main causes of chronic hepatitis, cirrhosis, hepatocellular carcinoma and liver transplantation. The identification of the viral genome quickly allowed delineation of genomic organization, and the structure and biochemical characterization of the proteins of HCV. However, it has been difficult to study its life cycle, as well as the development of antiviral agents due to the lack of a system of permissible culture. Numerous attempts have been reported to establish an in vitro system for the study of HCV. Recently, a system of efficient culture was established that allows replication of subgenomic molecules of HCV in a cell line of human hepatoma. In this revision, after a brief description of the molecular biology, means of transmission and clinical characteristics of hepatitis C, some of the experimental models are described that have been developed to date, focusing mainly on the subgenomic replicon system and their use in the development of new antiviral treatments.