The Lambda Variant in Argentina: Analyzing the Evolution and Spread of SARS-CoV-2 Lineage C.37.

The second wave of COVID-19 occurred in South America in early 2021 and was mainly driven by Gamma and Lambda variants. In this study, we aimed to describe the emergence and local genomic diversity of the SARS-CoV-2 Lambda variant in Argentina, from its initial entry into the country until its detection ceased. Molecular surveillance was conducted on 9356 samples from Argentina between October 2020 and April 2022, and sequencing, phylogenetic, and phylogeographic analyses were performed.

Omicron Waves in Argentina: Dynamics of SARS-CoV-2 Lineages BA.1, BA.2 and the Emerging BA.2.12.1 and BA.4/BA.5.

The COVID-19 pandemic has lately been driven by Omicron. This work aimed to study the dynamics of SARS-CoV-2 Omicron lineages during the third and fourth waves of COVID-19 in Argentina. Molecular surveillance was performed on 3431 samples from Argentina, between EW44/2021 and EW31/2022.

Assessing the hidden diversity underlying consensus sequences of SARS-CoV-2 using VICOS, a novel bioinformatic pipeline for identification of mixed viral populations.

Introduction: Coinfection with two SARS-CoV-2 viruses is still a very understudied phenomenon. Although next generation sequencing methods are very sensitive to detect heterogeneous viral populations in a sample, there is no standardized method for their characterization, so their clinical and epidemiological importance is unknown.

Material And Methods: We developed VICOS (Viral COinfection Surveillance), a new bioinformatic algorithm for variant calling, filtering and statistical analysis to identify samples suspected of being mixed SARS-CoV-2 populations from a large dataset in the framework of a community genomic surveillance.

Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina.

SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants.

Detection of toxigenic Clostridioides [Clostridium] difficile: Usefulness of two commercially available enzyme immunoassays and a PCR assay on stool samples and stool isolates.

The best laboratory diagnostic approach to detect Clostridioides [Clostridium] difficile infection (CDI) is a subject of ongoing debate. With the aim of evaluating four laboratory diagnostic methods, 250 unformed stools from patients with suspected CDI submitted to nine medical center laboratories from November 2010 to December 2011, were studied using: (1) an immunochromatographic rapid assay test that combines the qualitative determination of glutamate dehydrogenase (GDH) plus toxins A and B (QAB), the CDIFF QUIK CHEK COMPLETE assay; (2) an enzyme immunoassay for qualitative determination of toxins A and B, the RIDASCREEN™ C. difficile Toxin A/B assay (RAB); (3) a PCR for the toxin B gene assay (PCR); and (4) the toxigenic culture (TC).

Gene polymorphism profiles of drug-metabolising enzymes GSTM1, GSTT1 and GSTP1 in an Argentinian population.

Background: Glutathione S-transferases (GSTs) are drug-metabolising enzymes involved in biotransformation of carcinogens, drugs, xenobiotics and oxygen free radicals. Polymorphisms of GST genes contribute to inter-individual and population variability in the susceptibility to environmental risk factors, cancer predisposition and pharmacotherapy responses. However, data about GST variability in Argentina are lacking.

Multiloculated hydrocephalus.

Objective: The study aims to assess the treatment of progressive multiloculated hydrocephalus. In a retrospective study, the authors reviewed their experience with different treatment modalities.

Methods: We have retrospectively evaluated 93 patients with progressive multiloculated hydrocephalus operated between 1988 and 2010.

Pinealoblastomas in children.

Introduction: Series of pinealoblastomas (PB) usually comprise small number of cases as this tumor type is extremely rare and occurs mainly in childhood (especially under 9 years of age). Frequently, PB are reported together with others pineal parenchymal tumors (PPT) or pineal tumors, making characterization far from adequate.

Materials And Methods: Our series of CNS pediatric tumors comprises 1,350 cases of whom 16 are PPT, 12 PB, two pineocytomas (PC), and two mixed or transitional tumors (PC/PB).

Subependymal giant cell astrocytoma in children with tuberous sclerosis.

Methods: Out of 105 patients with tuberous sclerosis (TS) admitted to the Hospital Nacional de Pediatría "Juan P. Garrahan" (Buenos Aires, Argentina), we surgically treated 17 children between January 1988 and December 2000. Two patients were operated on because of epilepsy and 15 patients because of an intraventricular tumor (subependymal giant cell astrocytoma [SGCA]).

[Benign paroxysmal tonic upward gaze syndrome].

Introduction: The benign paroxysmal tonic upward gaze syndrome (BPTUG) is a rare condition. We present two new cases analyzing the clinical, genetic, evolution and therapeutic aspects.

Clinical Cases: Case 1.

Thalamic tumors in children.

Thalamic tumors (TT) merit individual analysis and must not be confused with tumors that, while involving the entire thalamus have a different origin. We analyzed 26 patients who fulfilled our criteria of having "strictly" TT. We examined incidence, clinical features, histology, response to treatment (mainly surgery), recurrence rate, mortality and prognosis.

[Chronic idiopathic intestinal pseudo-obstruction: visceral myopathy. Report of 4 cases].

Chronic intestinal pseudo-obstruction is the term applied to a heterogeneous group of functional motility disorders sharing a common clinical expression: signs and symptoms of bowel obstruction in absence of mechanical occlusion. It is caused by ineffective intestinal propulsion. The chronic form of intestinal pseudo-obstruction may be primary or secondary.