Temporal Series Analysis of Population Cycle Threshold Counts as a Predictor of Surge in Cases and Hospitalizations during the SARS-CoV-2 Pandemic.

Tools to predict surges in cases and hospitalizations during the COVID-19 pandemic may help guide public health decisions. Low cycle threshold (CT) counts may indicate greater SARS-CoV-2 concentrations in the respiratory tract, and thereby may be used as a surrogate marker of enhanced viral transmission. Several population studies have found an association between the oscillations in the mean CT over time and the evolution of the pandemic. For the first time, we applied temporal series analysis (Granger-type causality) to validate the CT counts as an epidemiological marker of forthcoming pandemic waves using samples and analyzing cases and hospital admissions during the third pandemic wave (October 2020 to May 2021) in Madrid. A total of 22,906 SARS-CoV-2 RT-PCR-positive nasopharyngeal swabs were evaluated; the mean CT value was 27.4 (SD: 2.1) (22.2% below 20 cycles). During this period, 422,110 cases and 36,727 hospital admissions were also recorded. A temporal association was found between the CT counts and the cases of COVID-19 with a lag of 9-10 days (p ≤ 0.01) and hospital admissions by COVID-19 (p < 0.04) with a lag of 2-6 days. According to a validated method to prove associations between variables that change over time, the short-term evolution of average CT counts in the population may forecast the evolution of the COVID-19 pandemic.

Characteristics of Heart Rate Tracings in Preterm Fetus.

Background and Objectives: Prematurity is currently a serious public health issue worldwide, because of its high associated morbidity and mortality. Optimizing the management of these pregnancies is of high priority to improve perinatal outcomes. One tool frequently used to determine the degree of fetal wellbeing is cardiotocography (CTG). A review of the available literature on fetal heart rate (FHR) monitoring in preterm fetuses shows that studies are scarce, and the evidence thus far is unclear. The lack of reference standards for CTG patterns in preterm fetuses can lead to misinterpretation of the changes observed in electronic fetal monitoring (EFM). The aims of this narrative review were to summarize the most relevant concepts in the field of CTG interpretation in preterm fetuses, and to provide a practical approach that can be useful in clinical practice. Materials and Methods: A MEDLINE search was carried out, and the published articles thus identified were reviewed. Results: Compared to term fetuses, preterm fetuses have a slightly higher baseline FHR. Heart rate is faster in more immature fetuses, and variability is lower and increases in more mature fetuses. Transitory, low-amplitude decelerations are more frequent during the second trimester. Transitory increases in FHR are less frequent and become more frequent and increase in amplitude as gestational age increases. Conclusions: The main characteristics of FHR tracings changes as gestation proceeds, and it is of fundamental importance to be aware of these changes in order to correctly interpret CTG patterns in preterm fetuses.

Identification of mercury species in minerals with different matrices and impurities by thermal desorption technique.

Because of its low concentration, its unique physico-chemical properties and the analytical difficulties associated with its measurement, the determination of mercury species in solids is not an easy task. Thermal desorption (HgTPD) is an attractive option for the identification of mercury species in solids due to its simplicity and accessibility. However, there are still issues that need to be solved for it to reach its full potential. One such issue is the availability of reference materials that will reproduce real mercury associations. The novelty of this study is the use of six uncommon mercury minerals, taken from around the world, and a sphalerite sample to expand the data base of reference materials for mercury speciation by thermal desorption at programmed temperature. In addition, by using such materials, a number of matrix effects can be ascertained. Different mercury associations were identified depending on the temperature of desorption, thereby validating the thermal desorption as a reliable technique for mercury speciation in solid samples and as a consequence improving the knowledge of the geochemistry of mercury in the environment.

Natal foraging philopatry in eastern Pacific hawksbill turtles.

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

Anidación y conservación de la tortuga lora (Lepidochelys olivacea) en playa Drake, península de Osa, Costa Rica (2006 a 2012) / Nesting and conservation of the Olive Ridley sea turtle (Lepidochelys olivacea) in playa Drake, Osa Peninsula, Costa Rica (2006-2012)

Resumen Desde 2006 a 2012, la anidación de la tortuga lora (Lepidochelys olivacea) fue monitoreada en bahía Drake, un enclave reconocido internacionalmente por su excelente oferta eco-turística que se localiza en la región noroeste de la península de Osa. Sorprendentemente, esta área dispone de playas de anidación solitaria de tortuga lora que han permanecido casi desadvertidas hasta fechas recientes. Durante este periodo de monitoreo, 958 nidos fueron registrados en playa Drake (promedio anual: 136.9; densidad: 3.80 nidos/100m de playa), de los cuales 363 (37.9%) fueron reubicados a un vivero. Antes de 2006, la pérdida anual de nidos fue superior al 85% debido al saqueo en playa; desde 2006, el porcentaje del saqueo de nidos se mantuvo en un promedio del 10.1%. Además, un total de 335 hembras fueron identificadas con placas metálicas; el promedio de la longitud curva del caparazón fue de 66.1cm; el promedio del ancho curvo del caparazón fue de 70.2cm, y el tamaño promedio por nidada fue de 96.3 huevos. El promedio del éxito de eclosión para los nidos reubicados en vivero fue de 79.2%, y más de 61 000 neonatos fueron liberados al mar durante este periodo. Este proyecto es un ejemplo de una iniciativa exitosa de conservación, eco-turismo y desarrollo comunitario.

Abstract The nesting of the Olive Ridley (Lepidochelys olivacea) sea turtle was studied from 2006 to 2012 in Drake Bay, Costa Rica, an important solitary nesting site and center of eco-tourism in the Osa Peninsula. During this period, 958 nests were recorded (mean: 136.9 nests per season; density: 3.8 nests/100m of beach per season), of which 38% were relocated to a hatchery. The incidence of poaching was reduced from 85% in 2005 to a mean of 10.1% from 2006-2012. A total of 335 nesting females were tagged; the mean curved length of carapace was 66.1cm, the mean curved width was 70.2cm, and the mean number of eggs per nest was 96.3. A mean rate of reproductive success of 79.2% was obtained and over 61 000 hatchlings were liberated from the hatchery. This project is an example of a successful community-based conservation and eco-tourism initiative. Rev. Biol. Trop. 63 (Suppl. 1): 117-129. Epub 2015 April 01.

A population of c-Kit(low)(CD45/TER119)- hepatic cell progenitors of 11-day postcoitus mouse embryo liver reconstitutes cell-depleted liver organoids.

Embryo liver morphogenesis takes place after gastrulation and starts with a ventral foregut evagination that reacts to factor signaling from both cardiac mesoderm and septum transversum mesenchyme. Current knowledge of the progenitor stem cell populations involved in this early embryo liver development is scarce. We describe here a population of 11-day postcoitus c-Kit(low)(CD45/TER119)- liver progenitors that selectively expressed hepatospecific genes and proteins in vivo, was self-maintained in vitro by long-term proliferation, and simultaneously differentiated into functional hepatocytes and bile duct cells. Purified c-Kit(low)(CD45/TER119)- liver cells cocultured with cell-depleted fetal liver fragments engrafted and repopulated the hepatic cell compartments of the latter organoids, suggesting that they may include the embryonic stem cells responsible for liver development.

Apoptotic rate: a new indicator for the quantification of the incidence of apoptosis in cell cultures.

BACKGROUND: Late apoptotic cells divide into apoptotic bodies and are missed by current detection methods. This results in an artificially low apoptotic index (AI). METHODS: This study proposes a flow cytometry-based ratiometric method that uses an internal reference standard of microbeads combined with fluorescein-annexin V binding and 7-aminoactinomycin D to enumerate viable, necrotic, and early and late apoptotic cells within specific subsets of a heterogeneous culture. RESULTS: In the absence of cell growth, the number of apoptotic cells that undergo fragmentation into apoptotic bodies in culture can also be determined accurately by this method. This information can then be used to obtain the apoptotic rate (AR), a new indicator of apoptosis that calculates the proportion of cells that have undergone apoptosis with respect to the total number of seeded cells. The main limitation of the method is that the AR is only suitable for the study of apoptosis in noncycling cells. CONCLUSIONS: This study reveals the superiority of the proposed method over the widely used Nicoletti method and current annexin-V binding methods. The AI did not reflect the true incidence of lymphocyte apoptosis, neither in response to lectins or phorbol esters, nor to serum deprivation. AR was more sensitive than AI, detecting apoptosis at lower concentrations of cell death inducers in all the subsets studied.