RESUMEN
Microbialites accrete where environmental conditions and microbial metabolisms promote lithification, commonly through carbonate cementation. On Little Ambergris Cay, Turks and Caicos Islands, microbial mats occur widely in peritidal environments above ooid sand but do not become lithified or preserved. Sediment cores and porewater geochemistry indicated that aerobic respiration and sulfide oxidation inhibit lithification and dissolve calcium carbonate sand despite widespread aragonite precipitation from platform surface waters. Here, we report that in tidally pumped environments, microbial metabolisms can negate the effects of taphonomically-favorable seawater chemistry on carbonate mineral saturation and microbialite development.
Asunto(s)
Compuestos de Calcio/química , Ecosistema , Óxidos/química , Arena/química , Arena/microbiología , Carbonato de Calcio/metabolismo , Carbonatos , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiología , Microbiota , Minerales , Agua de Mar/química , Agua de Mar/microbiología , Indias OccidentalesRESUMEN
Genome-resolved metagenomic sequencing approaches have led to a substantial increase in the recognized diversity of microorganisms; this included the discovery of novel metabolic pathways in previously recognized clades, and has enabled a more accurate determination of the extant distribution of key metabolisms and how they evolved over Earth history. Here, we present metagenome-assembled genomes of members of the Chloroflexota (formerly Chloroflexi or Green Nonsulfur Bacteria) order Aggregatilineales (formerly SBR1031 or Thermofonsia) discovered from sequencing of thick and expansive microbial mats present in an intertidal lagoon on Little Ambergris Cay in the Turks and Caicos Islands. These taxa included multiple new lineages of Type 2 reaction center-containing phototrophs that were not closely related to previously described phototrophic Chloroflexota-revealing a rich and intricate history of horizontal gene transfer and the evolution of phototrophy and other core metabolic pathways within this widespread phylum.
RESUMEN
OBJECTIVES: To compare the safety and antiviral activity of once (QD) or twice (BID) daily lopinavir/ritonavir (LPV/r) in combination with investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) in treatment-experienced subjects. METHODS: Subjects failing treatment with HIV-1 RNA > 1000 copies per milliliter received LPV/r tablets 800/200 mg QD (n = 300) or 400/100 mg BID (n = 299) with investigator-chosen nucleoside/nucleotide reverse transcriptase inhibitors. Efficacy was determined by the intent-to-treat time to loss of virologic response (ITT-TLOVR) algorithm. Safety, tolerability, adherence, impact of baseline protease mutations on virologic response, and emergence of resistance on therapy were assessed. RESULTS: Demographics were comparable across groups. By intent-to-treat time to loss of virologic response, 166 QD subjects (55.3%) and 155 BID subjects (51.8%) were responders at week 48 (P = 0.413), with similar mean increases in CD4 T-cell count. QD subjects demonstrated better adherence than BID subjects. The occurrence of treatment-related moderate/severe adverse events was comparable for all events except nausea, which was reported more frequently among BID-treated subjects. Emergence of new protease resistance mutations on treatment was similarly infrequent in both groups. CONCLUSION: LPV/r dosed QD resulted in increased treatment adherence and was as efficacious as BID LPV/r while providing similar safety, tolerability, and limited resistance evolution.
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Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1/efectos de los fármacos , Pirimidinonas/uso terapéutico , Ritonavir/uso terapéutico , Adulto , Anciano , Fármacos Anti-VIH/administración & dosificación , Fármacos Anti-VIH/efectos adversos , Fármacos Anti-VIH/uso terapéutico , Terapia Antirretroviral Altamente Activa/efectos adversos , Terapia Antirretroviral Altamente Activa/métodos , Recuento de Linfocito CD4 , Farmacorresistencia Viral , Femenino , Inhibidores de la Proteasa del VIH/administración & dosificación , Inhibidores de la Proteasa del VIH/efectos adversos , Humanos , Lopinavir , Masculino , Cumplimiento de la Medicación , Persona de Mediana Edad , Náusea/inducido químicamente , Pirimidinonas/administración & dosificación , Pirimidinonas/efectos adversos , Ritonavir/administración & dosificación , Ritonavir/efectos adversos , Carga Viral/efectos de los fármacos , Adulto JovenRESUMEN
We prospectively evaluated excretion of Giardia lamblia in children in day care centers in Houston by conducting two prevalence studies of 600 children enrolled in 30 DCC, day care centers, and an 18-month longitudinal study in 82 children in one center. In the two prevalence surveys, Giardia cysts were identified in 72 (21%) and 67 (26%) children, respectively, who provided stool specimens. Trophozoites were found in 15 (4%) and 8 (3%), respectively. There was no correlation between the frequency of recent diarrheal episodes and the finding of Giardia. Stool specimens containing cysts were significantly (P less than 0.0001) more frequent in the 13- to 30-month-old children than in children younger than 12 months. Children attending day care centers for more than 3 months were more likely to be excreting Giardia than those attending for less than 3 months. In the longitudinal study, cysts were detected in stool specimens from 27 (33%) of the 82 children at least once during the survey. Twelve children had Giardia cysts in weekly stool specimens for a mean of 6.2 +/- 1.2 months and trophozoites for 3.3 +/- 1.2 months. The number of enteric symptoms observed in children and the classification of nutritional status based on monthly height and weekly weight measurements did not differ significantly when infected and noninfected children were compared. Asymptomatic Giardia excretion in children younger than 36 months is common and appears to be well tolerated.
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Guarderías Infantiles , Giardiasis/epidemiología , Preescolar , Diarrea/epidemiología , Diarrea/parasitología , Heces/parasitología , Femenino , Giardiasis/parasitología , Humanos , Lactante , Recién Nacido , Estudios Longitudinales , Masculino , Estudios Prospectivos , TexasRESUMEN
PIP: A major criticism of the use of oral rehydration solution (ORS) in the treatment of diarrhea has been that the high sodium content of the solution might predispose the development of hypernatremia in infants not allowed access to additional free water and in whom glomerular filtration rate and urinary concentrating ability may be low. A study was undertaken in 1980 in Cairo, Egypt to assess the use of ORS. The study included 100 children under age 1, mean age 6.7 months, with dehydration secondary to diarrhea, and 17% were hypernatremic on admission, 27% hyponatremic and 56% isonatremic; the hypernatremic infants were found to be more dehydrated than the others. 24% of the hypernatremic infants had taken Rehydran whereas only 5% of the others had taken it and none had been given the medication in a proper fashion. Of the 17 with hypernatremia 16 completed the course of oral rehydration therapy and 63% had normal serum sodium values by 6 hours of therapy. It was found that the treatment of hypernatremic infants with ORS was successful while with the unsupervised use of Rehydran the risk of this condition was enhanced; errors made in the home included prolonged use of the solution and failure to use water. It is believed that because of widespread illiteracy sole reliance upon written instructions is potentially dangerous.^ieng
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Deshidratación/terapia , Diarrea Infantil/complicaciones , Fluidoterapia/efectos adversos , Deshidratación/etiología , Femenino , Humanos , Hipernatremia/inducido químicamente , Lactante , Recién Nacido , Masculino , Riesgo , Sodio/efectos adversos , Sodio/sangreAsunto(s)
Trasplante de Médula Ósea , Defensa del Niño/legislación & jurisprudencia , Consentimiento Paterno , Donantes de Tejidos , Obtención de Tejidos y Órganos , Adolescente , Adulto , Niño , Ética Médica , Humanos , Consentimiento Informado/legislación & jurisprudencia , Masculino , Medición de Riesgo , Hermanos , Estados UnidosRESUMEN
The usefulness of a single Widal test to diagnose typhoid fever in endemic areas was investigated. Reciprocal Salmonella typhi O and H titers greater than or equal to 40 and greater than or equal to 80, respectively, occurred in approximately 90% of 42 Mexican patients with bacteriologically-confirmed typhoid fever at the time of presentation to hospital and, by day 4 to 5 of clinical illness, in 70% of U.S. adult volunteers who developed typhoid fever in the course of vaccine efficacy trials but in only 0.7% (O) to 3% (H) of 275 healthy individuals from a non-endemic area. Healthy Peruvians from areas endemic for typhoid fever commonly had antibody which was age-related. Peak prevalence was found in 15- to 19-yr-olds in whom 29% had O titers greater than or equal to 40 and 76% had H titers greater than or equal to 80. A single Widal test in an unvaccinated individual showing elevated O and H titers is strongly suggestive of typhoid fever if the person comes from a non-endemic area or is a child less than 10 yr of age in an endemic area. Because of the high prevalence of antibody amongst healthy invididuals over 10 yr of age in endemic, areas, a single Widal test offers virtually no diagnostic assistance in adolescents and adults.
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Pruebas de Aglutinación , Fiebre Tifoidea/diagnóstico , Adolescente , Adulto , Anciano , Anticuerpos Antibacterianos/análisis , Antígenos Bacterianos/análisis , Niño , Preescolar , Humanos , Maryland , México , Persona de Mediana Edad , Perú , Salmonella typhi/inmunología , Fiebre Tifoidea/epidemiología , Fiebre Tifoidea/inmunologíaRESUMEN
PIP: This report describes the authors' experiences among Apache Indians who required rehydration therapy because of acute diarrhea. About 400 children, aged less than 2 years, who were strong enough to drink, were given oral glucose-electrolyte solutions. The solution contained, in millimoles per liter, sodium (81), potassium (18), chloride (71), bicarbonate (28), and glucost (139). The cost of the formula is 2.5 cents per liter. In children with a 2 degree volume depletion, more of the solution was required (statistically significant) than if the child suffered 1 degree volume depletion; however, 9 of 11 children with 2 degree depletion were adequately hydrated 3-6 hours after administration. Moderate electrolyte abnormalities, which included hypo- and hypernatremia and acidosis, were corrected or improved during the administration of the oral rehydration therapy. Plasma potassium concentrations showed little change. The oral therapy failed in 2 children due to malabsorbed glucose, but both were successfully treated with intravenous fluids, a carbohydrate-free formula, and broad-spectrum antibiotics. The ad libitum sue of oral therapy is effective and should help reduce infant mortality and morbidity due to diarrhea.^ieng