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Epidemiology and Detection of BK and JC Polyomaviruses in Healthy and Clinical Populations

BK polyomavirus (BKV) and JC polyomavirus (JCV) are ubiquitous human polyomaviruses that usually cause asymptomatic primary infection followed by latent persistence. Reported prevalence differs according to population, age, geographic region, specimen type, detection method, and whether infection is assessed by serology or viral DNA. BKV seroprevalence is generally high, ranging from approximately 65% to 99% across the supplied studies, whereas JCV seroprevalence is more variable and generally lower, with a meta-analytic estimate of 61%. Viral DNA detection is less frequent and varies substantially by specimen and population. Available data do not establish reliable prevalence estimates for BKV genotypes I–IV, although genotype III was identified among urinary BKV-positive samples in one study. Reactivation is clinically important in immunocompromised populations, particularly because BKV is associated with BK polyomavirus–associated nephropathy and JCV with progressive multifocal leukoencephalopathy (PMID: 40509546; PMID: 31911182).

Question: Prevalence of BKV I-IV, JCV

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Reverse-Genetics Contributions to Approved Viral Vaccines

Reverse-genetics technology has contributed to the development and manufacture of several viral vaccines, but the supplied evidence varies in its ability to link specific products directly to the method. The clearest evidence concerns influenza vaccines, particularly live attenuated influenza vaccines (LAIVs) and other reassortant or recombinant preparations. These products can be generated by combining hemagglutinin and neuraminidase genes from relevant circulating strains with the six internal gene segments of an attenuated master donor virus. Reverse genetics also supported the construction of Dengvaxia, a tetravalent live-attenuated chimeric dengue vaccine based on yellow fever 17D backbones expressing dengue structural proteins. Evidence concerning rotavirus and other viral vaccines indicates contributions from reverse-genetics or recombinant systems, but does not consistently establish direct derivation of each licensed product. Several experimental influenza and arenavirus candidates should not be classified as approved vaccines. Overall, reverse genetics is best understood as an enabling technology for defined vaccine-virus construction, strain updating, and vaccine development rather than as evidence that a particular product was approved exclusively through this method.

Question: approved viral vaccines developed through reverse genetics technology

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Long COVID A Heterogeneous Multisystem Post-Infectious Condition

Long COVID, also termed post-COVID-19 condition or post-acute sequelae of SARS-CoV-2 infection (PASC), comprises symptoms and health complications that persist, recur, or newly develop after acute COVID-19. It can follow severe or mild infection, including infection managed without hospitalization, and affects adults and children. Manifestations span respiratory, cardiovascular, neurological, musculoskeletal, gastrointestinal, psychological, and autonomic domains, with fatigue, post-exertional worsening, dyspnea, cognitive difficulties, pain, palpitations, sleep disturbance, and altered smell or taste among commonly reported symptoms (PMID: 34024217; PMID: 34163217; PMID: 34265229). Long COVID is biologically heterogeneous and may reflect overlapping tissue injury, viral persistence or remnants, persistent inflammation, immune dysregulation, autoimmunity, endothelial or microvascular abnormalities, and autonomic dysfunction (PMID: 35874958; PMID: 35272932; PMID: 37351054). Its symptoms may last beyond a year and impair daily functioning, education, employment, and quality of life. Diagnosis and care therefore require individualized, multidisciplinary assessment, while disease-specific treatments and reliable biomarkers remain insufficiently established.

Question: longcovid

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Hipotiroidismo y tiroiditis tras la vacunación contra COVID-19 revisión de la evidencia disponible

La evidencia disponible indica que la tiroiditis subaguda y las alteraciones transitorias de la función tiroidea pueden aparecer después de la infección por SARS-CoV-2 y, con menor frecuencia, tras la vacunación contra COVID-19. Los datos sobre AstraZeneca (ChAdOx1/AZD1222/Vaxzevria) proceden principalmente de informes y series de casos, con escasos estudios observacionales y sin comparaciones directas adecuadas con la infección. La presentación posvacunal suele corresponder a una fase hipotiroidea transitoria de una tiroiditis subaguda, precedida por tirotoxicosis. Aunque se han descrito casos de hipotiroidismo manifiesto y exacerbación de enfermedad tiroidea previa, no se ha demostrado causalidad individual ni un riesgo específico superior al asociado con SARS-CoV-2. La mayoría de los casos evoluciona favorablemente, pero puede requerirse seguimiento de TSH y T4 libre.

Question: Hipotiroidismo post vacunación vs. COVID29 con vacuna Astra Zeneca

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Tirzepatida y riesgo cardiovascular revisión de la evidencia clínica disponible

La evidencia disponible indica que tirzepatida presenta un perfil cardiovascular favorable y no se asocia con un aumento del riesgo de eventos cardiovasculares. Sus efectos sobre el peso corporal, la glucemia, la presión arterial y algunos parámetros lipídicos sugieren una mejoría del perfil cardiometabólico. Los ensayos y metaanálisis muestran tendencias hacia menos eventos cardiovasculares, mientras que algunos estudios observacionales han descrito asociaciones con menor incidencia de eventos y mortalidad. Sin embargo, los análisis aleatorizados no han demostrado de forma concluyente una reducción superior de los eventos cardiovasculares mayores frente a comparadores activos. En SURPASS-CVOT, tirzepatida fue no inferior a dulaglutida para muerte cardiovascular, infarto de miocardio o accidente cerebrovascular, y los análisis cardiorrenales post hoc sugirieron beneficios adicionales, aunque estos deben interpretarse con cautela. En conjunto, tirzepatida parece cardiovascularmente segura y posiblemente beneficiosa, pero la magnitud, independencia y causalidad de su efecto sobre los desenlaces cardiovasculares requieren confirmación.

Question: Ha mejorado el riesgo cardiovascular tirzepatida?

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Market Potential and Introduction Strategies for Varicella Vaccine in Low- and Middle-Income Countries

Available evidence indicates moderate to substantial but highly country-dependent market potential for varicella vaccine in low- and middle-income countries (LMICs). The opportunity is shaped by disease burden, affordability, financing, immunization infrastructure, surveillance, and the choice between one- and two-dose schedules. Evidence from Colombia and Costa Rica demonstrates that universal vaccination can be cost-effective and can substantially reduce cases, hospitalizations, and complications in middle-income settings. Studies from India and other developing-country contexts suggest that private-sector demand already exists but is constrained by affordability, awareness, and competing vaccine priorities. Additional opportunities may arise through targeted vaccination of adolescents, refugees and migrants, women of childbearing age, and health-care workers. However, the available evidence does not provide reliable country-specific estimates of demand, procurement volume, willingness to pay, market size, or budget impact. The strongest near-term opportunity is therefore likely to involve selected middle- and lower-middle-income countries, urban private markets, and targeted or phased public-sector programs supported by affordable pricing and sustainable financing.

Question: Vaccine market potential of varicella vaccine in low middle income countries

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Chronic Active Gastritis With Reactive Change Morphology Etiologic Considerations and Diagnostic Integration

Chronic active gastritis with reactive change is a pattern of gastric mucosal injury combining predominantly lymphoplasmacytic inflammation with superimposed neutrophilic activity and epithelial injury or regeneration. Histologic features may include foveolar hyperplasia, elongated or corkscrew-shaped pits, regenerative epithelial atypia, mucin depletion, surface erosion or ulceration, edema, and extension of smooth-muscle fibers into the lamina propria. Although Helicobacter pylori is a major consideration, reactive change is nonspecific and may accompany chemical or reflux-related injury, medication-associated damage, and other forms of non-H. pylori gastritis. Accurate interpretation requires assessment of inflammatory distribution and severity, organisms, glandular atrophy, intestinal metaplasia, epithelial atypia, exposure history, and clinical and endoscopic findings. This review summarizes the overlapping morphology, principal etiologic considerations, and limitations of diagnosing chronic active gastritis with reactive change from biopsy findings alone.

Question: Chronic active gastritis reactive change

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Persistent and Reactivated Viral Infections as Contributors to Neurodegeneration

Persistent, reactivated, or infection-triggered immune responses may contribute to neurodegeneration, although available evidence does not establish a universal causal pathway or show that viral infection is sufficient to cause disease. Herpes simplex virus type 1 (HSV-1) provides the strongest example, with experimental studies linking recurrent infection to amyloid-β accumulation, tau hyperphosphorylation, neuroinflammation, synaptic impairment, cognitive decline, and altered neuronal aging-associated markers. Other models indicate that non-lytic persistent infection, early-life infection, and infection-triggered immune responses can promote neuronal injury through maladaptive microglial activation and cytotoxic T-cell responses, including after viral clearance. Human evidence includes a single case of progressive deterioration associated with recurrent or persistent HSV-1 infection and an epidemiological association between higher cytomegalovirus antibody levels and faster cognitive decline, but these findings remain limited and non-definitive. Overall, viral effects may operate through chronic neuroinflammation, direct or indirect neuronal injury, disrupted amyloid-β and tau biology, synaptic dysfunction, oxidative stress, and accelerated cellular aging. Viral infection is therefore best regarded as a possible disease-modifying contributor interacting with host susceptibility and other risk factors.

Question: Does persistent or reactivated viral infection contribute to neurodegeneration?

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Development Principles for Elemental Nutrition Formulations

Elemental nutrition formulations are designed to provide nutrients in forms requiring minimal gastrointestinal digestion while limiting exposure to intact proteins, potential allergens, poorly absorbed substrates, and other gastrointestinal burdens. Development must integrate clinical indication, age, disease state, route and duration of administration, nutritional completeness, digestibility, osmolality, gastrointestinal tolerance, palatability, physical stability, manufacturing quality, and clinical validation. Free-amino-acid formulas are truly elemental, whereas peptide-based and extensively hydrolyzed products are semi-elemental categories with different properties and clinical roles. Key formulation decisions concern the nitrogen, carbohydrate, lipid, electrolyte, micronutrient, and functional-ingredient systems, as well as energy density, water content, renal solute load, viscosity, tube compatibility, and storage stability. Because patient requirements and tolerance vary substantially, a universal formulation is unlikely to be appropriate. Evidence supports individualized, indication-specific development but remains limited by product heterogeneity and a relative scarcity of large prospective comparative trials (PMID: 39001958; PMID: 40290002).

Question: Elemental nutrition formulations development pl help

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Umbilical Cord Management in Twin Pregnancies Evidence Clinical Considerations and Remaining Uncertainties

Delayed cord clamping (DCC), generally for 30–60 seconds, appears feasible in many twin pregnancies when both infants and the mother are clinically stable. Observational studies associate DCC with higher neonatal hemoglobin or hematocrit and, in some cohorts, lower transfusion, respiratory morbidity, or neonatal intensive care admission. Evidence from preterm twins is mixed, and a small randomized study of preterm multiple births did not demonstrate significant neonatal benefits while reporting more postpartum hemorrhage in the DCC group. Maternal bleeding outcomes overall have not shown a consistent increase, but reporting is limited and operative deliveries may require particular caution. Chorionicity, birth order, delivery mode, placental anatomy, and discordant neonatal condition complicate management, especially in monochorionic twins. Cord milking cannot currently be considered equivalent to DCC or recommended routinely. Twin-specific evidence remains predominantly observational, heterogeneous, and insufficient to establish a universal duration, positioning strategy, or approach to monochorionic pregnancies.

Question: umbilical cord management in twin pregnancy

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