Self-Diagnosis of SARS-CoV-2 from Saliva Samples at Home: Isothermal Amplification Enabled by Do-It-Yourself Portable Incubators and Laminated Poly-ethyl Sulfonate Membranes

COVID-19 made explicit the need for rethinking the way in which we conduct testing for epidemic emergencies. During the COVID-19 pandemic, the dependence on centralized lab facilities and resource-intensive methodologies (e.g., RT-qPCR methods) greatly limited the deployment of widespread testing efforts in many developed and underdeveloped countries. Here, we illustrate the development of a simple and portable diagnostic kit that enables self-diagnosis of COVID-19 at home from saliva samples. We describe the development of a do-it-yourself (DIY) incubator for Eppendorf tubes that can be used to conduct SARS-CoV-2 detection with competitive sensitivity and selectivity from saliva at home. In a proof-of-concept experiment, we assembled Eppendorf-tube incubators at our home shop, prepared a single-tube mix of reagents and LAMP primers in our lab, and deployed these COVID-19 detection kits using urban delivery systems (i.e., Rappifavor or Uber) to more than 15 different locations in Monterrey, México. This straightforward strategy enabled rapid and cost-effective at-home molecular diagnostics of SARS-CoV-2 from real saliva samples with a high sensitivity (100%) and high selectivity (87%).

Mosquito metallomics reveal copper and iron as critical factors for Plasmodium infection

Iron and copper chelation restricts Plasmodium growth in vitro and in mammalian hosts. The parasite alters metal homeostasis in red blood cells to its favor, for example metabolizing hemoglobin to hemozoin. Metal interactions with the mosquito have not, however, been studied. Here, we describe the metallomes of Anopheles albimanus and Aedes aegypti throughout their life cycle and following a blood meal. Consistent with previous reports, we found evidence of maternal iron deposition in embryos of Ae. aegypti, but less so in An. albimanus. Sodium, potassium, iron, and copper are present at higher concentrations during larval developmental stages. Two An. albimanus phenotypes that differ in their susceptibility to Plasmodium berghei infection were studied. The susceptible white stripe (ws) phenotype was named after a dorsal white stripe apparent during larval stages 3, 4, and pupae. During larval stage 3, ws larvae accumulate more iron and copper than the resistant brown stripe (bs) phenotype counterparts. A similar increase in copper and iron accumulation was also observed in the susceptible ws, but not in the resistant bs phenotype following P. berghei infection. Feeding ws mosquitoes with extracellular iron and copper chelators before and after receiving Plasmodium-infected blood protected from infection and simultaneously affected follicular development in the case of iron chelation. Unexpectedly, the application of the iron chelator to the bs strain reverted resistance to infection. Besides a drop in iron, iron-chelated bs mosquitoes experienced a concomitant loss of copper. Thus, the effect of metal chelation on P. berghei infectivity was strain-specific.

To establish a life cycle between insect and mammalian hosts, the malaria parasite has evolved mechanisms to manage metal ions from the distinct microenvironments it encounters. Previous work has addressed how interference using metal chelation affects parasite development in human, primate, and rodent hosts. Similar studies in mosquito species that harbor Plasmodium have not been performed. Here, we address such micronutrient relationships in three steps. First, we characterized how the metallome fluctuates during development in two species of mosquito. Second, we asked whether susceptibility to Plasmodium infection correlated with a differential response in mosquito metal homeostasis. Third, we tested the effects of iron and copper chelation treatment of adult mosquitoes concerning propensity of infection and mosquito reproduction. Metal ions offer a promising target in the ongoing efforts to control the mosquito-borne disease.

Serological Test to Determine Exposure to SARS-CoV-2: ELISA Based on the Receptor-Binding Domain of the Spike Protein (S-RBDN318-V510) Expressed in Escherichia coli

Massive worldwide serological testing for SARS-CoV-2 is needed to determine the extent of virus exposure in a particular region, the ratio of symptomatic to asymptomatic infected persons, and the duration and extent of immunity after infection. To achieve this, the development and production of reliable and cost-effective SARS-CoV-2 antigens is critical. We report the bacterial production of the peptide S-RBDN318-V510, which contains the receptor-binding domain of the SARS-CoV-2 spike protein (region of 193 amino acid residues from asparagine-318 to valine-510) of the SARS-CoV-2 spike protein. We purified this peptide using a straightforward approach involving bacterial lysis, his-tag-mediated affinity chromatography, and imidazole-assisted refolding. The antigen performances of S-RBDN318-V510 and a commercial full-length spike protein were compared in ELISAs. In direct ELISAs, where the antigen was directly bound to the ELISA surface, both antigens discriminated sera from non-exposed and exposed individuals. However, the discriminating resolution was better in ELISAs that used the full-spike antigen than the S-RBDN318-V510. Attachment of the antigens to the ELISA surface using a layer of anti-histidine antibodies gave equivalent resolution for both S-RBDN318-V510 and the full-length spike protein. Results demonstrate that ELISA-functional SARS-CoV-2 antigens can be produced in bacterial cultures, and that S-RBDN318-V510 may represent a cost-effective alternative to the use of structurally more complex antigens in serological COVID-19 testing.

Colorimetric loop-mediated isothermal amplification (LAMP) for cost-effective and quantitative detection of SARS-CoV-2: the change in color in LAMP-based assays quantitatively correlates with viral copy number

We demonstrate a loop-mediated isothermal amplification (LAMP) method to detect and amplify SARS-CoV-2 genetic sequences using a set of in-house designed initiators that target regions encoding the N protein. We were able to detect and amplify SARS-CoV-2 nucleic acids in the range of 62 to 2 × 105 DNA copies by this straightforward method. Using synthetic SARS-CoV-2 samples and RNA extracts from patients, we demonstrate that colorimetric LAMP is a quantitative method comparable in diagnostic performance to RT-qPCR (i.e., sensitivity of 92.85% and specificity of 81.25% in a set of 44 RNA extracts from patients analyzed in a hospital setting).

ADIPOQ single nucleotide polymorphisms and breast cancer in northeastern Mexican women

BACKGROUND

Adiponectin gene (ADIPOQ) polymorphisms have been shown to affect adiponectin serum concentration and some have been associated with breast cancer (BC) risk. The aims of this study were to describe the frequency of single nucleotide polymorphisms (SNPs) of ADIPOQ in Mexican women with BC and to determine if they show an association with it.

METHODS

DNA samples from 397 patients and 355 controls were tested for the ADIPOQ gene SNPs: rs2241766 (GT) and rs1501299 (GT) by TaqMan allelic discrimination assay. Hardy-Weinberg equilibrium (HWE) was tested. Multiple SNP inheritance models adjusted by age and body mass index (BMI) were examined for the SNP rs1501299.

RESULTS

We found that in the frequency analysis of rs1501299 without adjusting the BMI and age, the genotype distribution had a statistically significant difference (P = 0.003). The T allele was associated with a BC risk (OR, 1.99; 95% CI 1.13-3.51, TT vs. GG; OR, 1.53; 95% CI 1.12-2.09, GT vs. GG). The SNP rs2241766 was in HW disequilibrium in controls. In conclusion, the rs1501299 polymorphism is associated with a BC risk.

CONCLUSIONS

Identification of the genotype of these polymorphisms in patients with BC can contribute to integrate the risk profile in both patients and their relatives as part of a comprehensive approach and increasingly more personalized medicine.

Genetic Variants in the 3'UTR of BRCA1 and BRCA2 Genes and their Putative Effects on the microRNA Mechanism in Hereditary Breast and Ovarian Cancer

Hereditary breast and ovarian cancer (HBOC) syndrome is mainly caused by mutations in the BRCA1 and BRCA2 genes. The 3’UTR region allows for the binding of microRNAs, which are involved in genetic tune regulation. We aimed to identify allelic variants on 3’UTR miRNA-binding sites in the BRCA1 and BRCA2 genes in HBOC patients. Blood samples were obtained from 50 patients with HBOC and from 50 controls. The 3’UTR regions of BRCA1 and BRCA2 were amplified by PCR and sequenced to identify genetic variants using bioinformatics tools. We detected nine polymorphisms in 3’UTR, namely: four in BRCA1 (rs3092995 (C/G), rs8176318 (C/T), rs111791349 (G/A), and rs12516 (C/T)) and five in BRCA2 (rs15869 (A/C), rs7334543 (A/G), rs1157836 (A/G), and rs75353978 (TT/del TT)). A new variant in position c.*457 (A/C) on 3’UTR of BRCA2 was also identified. The following three variants increased the risk of HBOC in the study population: rs111791349-A, rs15869-C, and c.*457-C (odds ratio (OR) range 3.7–15.4; p < 0.05). Genetic variants into the 3’UTR of BRCA1 and BRCA2 increased the risk of HBOC between 3.7–15.4 times in the study population. The presence/absence of these polymorphisms may influence the loss/creation of miRNA binding sites, such as hsa-miR-1248 in BRCA1 3′UTR or the hsa-miR-548 family binding site in BRCA2. Our results add new evidence of miRNA participation in the pathogenesis of HBOC.

Fast-track extubation in patients after intracranial hematoma surgery

Early extubation, also known as fast track, is desirable after intracranial hematoma surgery to avoid ventilator-associated complications associated with admission to an intensive care unit (ICU). The objective of the present study was to determine whether ICU stay and ventilator-associated complications are reduced in patients who received surgery for intracranial hematoma if they are extubated early. A total of 17 patients were randomly assigned to two groups: In Group 1, patients were extubated early or using the fast track method, while those in Group 2 were conventionally extubated at a later stage and were managed at the ICU. Patients from both groups were assessed on admission to the operating room per the established standards and after the selection criteria had been confirmed, general anesthesia was applied. Extubation time and hemodynamic stability (number of anesthetic adjustments required to maintain hemodynamic parameters within 20% of the predicted values) were assessed post-operatively. Patients in the conventional group (n=10) were transferred to the ICU and extubated at 8 h post-operatively; hemodynamic stability and the presence of complications were evaluated. The fast track group had no complications associated with ventilation or any other parameter. All patients extubated in a conventional manner and who were transferred to the ICU presented with complications, including seizures, aspiration, atelectasis or failed extubation. In the future, fast track should be regarded as a routine technique in patients who meet the required criteria, so that they may be discharged quickly and with fewer complications. The present study was authorized by the ethics committee of the hospital and the research sub-directorate with the number AN14-003; it was submitted to and approved by the ISRCTN registry for clinical trials (ID, ISRCTN16924441).

Cytological diagnosis of Rosai-Dorfman disease: A case report and revision of the literature

Rosai-Dorfman disease also known as sinus histiocytosis with massive lymphadenopathy (SHML) is characterized by distorted lymph node architecture with marked dilation of lymphatic sinuses occupied by numerous lymphocytes, as well as histiocytes with vesicular nucleus and abundant clear cytoplasm with phagocytized lymphocytes or plasma cells, also known as ‘emperipolesis’. This disease of unknown etiology progresses with a benign prognosis strictly and only when an early diagnosis and treatment is made. A late diagnosis and a generalized lymph node involvement contribute to a poor prognosis. In this study, we focussed on the cytological characteristics of the Rosai-Dorfman disease and differential diagnoses. We reported a case of a 61-year-old Mexican male with a 9-month history of painless bilateral cervical masses and low-grade fever with the final diagnosis of Rosai-Dorfman disease. The final diagnosis was made by fine needle aspiration (FNA) biopsy of parotid gland and cervical lymph node. In conclusion, FNA biopsy can be enough to make the diagnosis in most cases due to the distinct cytological features of SHML, thereby avoiding more invasive approaches that potentially are unnecessary.

Extrapituitary growth hormone synthesis in humans

The gene for pituitary growth hormone (GH-N) in man belongs to a multigene locus located at chromosome 17q24.2, which also harbors four additional genes: one for a placental variant of GH-N (named GH-V) and three of chorionic somatommamotropin (CSH) type. Their tandem arrangement from 5' to 3' is: GH-N, CSH-L, CSH-1, GH-V and CSH-2. GH-N is mainly expressed in the pituitary from birth throughout life, while the remaining genes are expressed in the placenta of pregnant women. Pituitary somatotrophs secrete GH into the bloodstream to act at receptor sites in most tissues. GH participates in the regulation of several complex physiological processes, including growth and metabolism. Recently, the presence of GH has been described in several extrapituitary sites, such as neural, ocular, reproductive, immune, cardiovascular, muscular, dermal and skeletal tissues. It has been proposed that GH has an autocrine action in these tissues. While the body of evidence for its presence is constantly growing, research of its possible function and implications lag behind. In this review we highlight the evidence of extrapituitary synthesis of GH in humans.

Olfactomedin-like 3 (OLFML3) gene expression in baboon and human ocular tissues: cornea, lens, uvea, and retina

BACKGROUND

Olfactomedin-like is a family of polyfunctional polymeric glycoproteins. This family has at least four members. One member of this family is OLFML3, which is preferentially expressed in placenta but is also detected in other adult tissues including the liver and heart. However, its orthologous rat gene is expressed in the iris, sclera, trabecular meshwork, retina, and optic nerve.

METHODS

OLFML3 messenger amplification was performed by RT-PCR from human and baboon ocular tissues. The products were cloned and sequenced.

RESULTS

We report OLFML3 expression in human and baboon eye. The full coding DNA sequence has 1221 bp, from which an open reading frame of 406 amino acid was obtained. The baboon OLFML3 gene nucleotidic sequence has 98% and amino acidic 99% similarity with humans.

CONCLUSIONS

OLFML3 gene expression in human and baboon ocular tissues and its high similarity make the baboon a powerful model to deduce the physiological and/or metabolic function of this protein in the eye.