RESPIRATORY PARAMETERS OF COVID-19 PATIENTS AFTER THE PRONE POSITION

<p>Hypoxemia is a condition when there is a lack of oxygen levels in the blood, especially from the arteries. In the early stages of COVID-19, several mechanisms such as intrapulmonary shunting, loss of pulmonary perfusion regulation, intravascular micro thrombus, and impaired diffusion capacity can contribute to the development of arterial hypoxemia, although there is no increase in respiratory work. The prone position is one of the most widely used therapies for patients with hypoxemia because the dorsal area has a large number of alveolar units that are not compressed by the weight of the abdominal cavity and mediastinum, thus creating a more efficient area for gas exchange. This study aimed to determine the effect of the prone position on changes in respiratory parameters of COVID-19 patients. This study used the descriptive correlation method on 27 respondents with purposive sampling. Each respondent was given a prone position for three hours and being observed before, during the three-hour, and after one hour of the prone position administration”. The results of the descriptive analysis of this study showed that the majority of respondents were middle adulthood (63%) with 70% of the respondents being male, 59% having a history of hypertension, and 85% experiencing coagulation disorders. The change in the mean respiratory rate during one hour of supination after three hours of prone position in males was greater than that in females although the mean decrease in oxygen saturation was the same. This shows that the prone position for three hours accompanied by oxygen therapy made an improvement in respiratory status in COVID-19 patients, although it needs further investigation with more respondents and different research methods.</p>

Nicotine Neurotoxicity Involves Low Wnt1 Signaling in Spinal Locomotor Networks of the Postnatal Rodent Spinal Cord

The postnatal rodent spinal cord in-vitro is a useful model to investigate early pathophysiological changes after injury. While low dose nicotine (1 µM) induces neuroprotection, how higher doses affect spinal networks is unknown. Using spinal preparations of postnatal wild-type Wistar rat and Wnt1Cre2:Rosa26Tom double-transgenic mouse, we studied the effect of nicotine (0.5–10 µM) on locomotor networks in-vitro. Nicotine 10 µM induced motoneuron depolarization, suppressed monosynaptic reflexes, and decreased fictive locomotion in rat spinal cord. Delayed fall in neuronal numbers (including motoneurons) of central and ventral regions emerged without loss of dorsal neurons. Conversely, nicotine (0.5–1 µM) preserved neurons throughout the spinal cord and strongly activated the Wnt1 signaling pathway. High-dose nicotine enhanced expression of S100 and GFAP in astrocytes indicating a stress response. Excitotoxicity induced by kainate was contrasted by nicotine (10 µM) in the dorsal area and persisted in central and ventral regions with no change in basal Wnt signaling. When combining nicotine with kainate, the activation of Wnt1 was reduced compared to kainate/sham. The present results suggest that high dose nicotine was neurotoxic to central and ventral spinal neurons as the neuroprotective role of Wnt signaling became attenuated. This also corroborates the risk of cigarette smoking for the foetus/newborn since tobacco contains nicotine.

Nicotine Neurotoxicity Involves Low Wnt1 Signaling in Spinal Locomotor Networks of the Postnatal Rodent Spinal Cord

The postnatal rodent spinal cord in-vitro is a useful model to investigate early pathophysiological changes after injury. While low dose nicotine (1&micro;M) induces neuroprotection, how higher doses affect spinal networks is unknown. Using spinal preparations of postnatal wild-type Wistar rat and Wnt1Cre2:Rosa26Tom double-transgenic mouse, we studied the effect of nicotine (0.5-10&micro;M) on locomotor networks in-vitro. Nicotine 10&micro;M induced motoneuron depolarization, suppressed monosynaptic reflexes, and decreased fictive locomotion in rat spinal cord. Delayed fall in neuronal numbers (including motoneurons) of central and ventral regions emerged without loss of dorsal neurons. Conversely, nicotine (0.5-1&micro;M) preserved neurons throughout the spinal cord and strongly activated the Wnt1 signaling pathway. High-dose nicotine enhanced expression of S100 and GFAP in astrocytes suggesting their response to stress. Excitotoxicity induced by kainate was contrasted by nicotine (10&micro;M) in the dorsal area and persisted in central and ventral regions with no change basal Wnt signaling. When combining nicotine with kainate, the activation of Wnt1 was reduced compared to kainate/sham. The present results suggest that high dose nicotine was neurotoxic to central and ventral spinal neurons as the neuroprotective role of Wnt signaling became attenuated. This also corroborates the risk of cigarette smoking for the foetus/newborn since tobacco contains nicotine.

A Comparative Study of Biocompatibility in Rat Connective Tissue of a New Mineral Trioxide Compound (Theracal) versus MTA and a Bioactive G3 Glass

The aim of this paper was to assess the differences in tissue response to implantation during 15, 30 and 45 days in the subcutaneous connective tissue of Wistar rats from three biomaterials: Angelus MTA®, Theracal LC®, and Angelus MTA® to which 25% bioglass G3 was added. Twenty-four Wistar rats were used, the materials were inserted into the rat’s dorsal area in silicone tubes 5 mm long by 1.5 mm diameter. Histological reaction was assessed at 15, 30, and 45 days after implantation. They were then stained with hematoxylin eosin and evaluated by two observers. Data were analyzed using Fisher’s exact test and Mann–Whitney’s U test was used to determine the association between variables. Angelus MTA induced the formation of dystrophic calcifications twice as much as Theracal LC (p < 0.05). The addition of G3 did not affect the greater or lesser occurrence of calcifications (p > 0.05). Theracal LC and MTA plus G3 caused an inflammatory reaction, which was chronic at 15 days and decreased in intensity, almost disappearing after 45 days. Theracal LC, as well as Angelus MTA plus G3, were well tolerated when implanted in the subcutaneous connective tissue of rat. Histologically, no inconvenience was found for the use by direct contact of Theracal LC, and the mixture of MTA with 25% bioactive glass G3, in the tissue of Wistar rats.

Respuesta reproductiva, metabólica y cambios corporales en ovejas alimentadas con dos niveles de energía

Objetivo. Evaluar la respuesta reproductiva, estado metabólico y cambios corporales en ovejas Dorper y Katahdin suplementadas con dos niveles de energía previo al empadre. Materiales y métodos. Se utilizaron 14 hembras Katahdin y 13 Dorper distribuidas en 2 tratamientos a las cuales se les sincronizó el celo. Catorce días previo a la sincronización de estros, las ovejas se distribuyeron en 2 tratamientos de acuerdo con el nivel de energía en la dieta, T1:2.0 y T2:2.5 Mcal kg-1 de EM. La alimentación abarcó 14 días de adaptación y 14 de alimentación con dieta integral. Al inicio y al final del estudio se midió el espesor de grasa dorsal, área del ojo de la costilla, peso corporal y concentraciones de glucosa e insulina. Se midieron los principales parámetros reproductivos como respuesta a estro, porcentaje de gestación y prolificidad. Se realizaron análisis de varianza y pruebas de ji cuadrada para determinar el efecto del nivel de energía y el genotipo. Resultados. El genotipo y el nivel de energía no afectaron ninguna de las variables medidas, aunque se encontró que con ambos niveles de energía existió un incremento en las concentraciones de glucosa, así como una ganancia en peso, grasa corporal y área del ojo de la costilla. Conclusiones. Debido a que no existió diferencia en los parámetros reproductivos y cambios corporales en ovejas al alimentarlas con los dos niveles de energía, es mejor la alimentación con 2.0 Mcal kg-1 de EM, ya que reduce costos de alimentación.

Global Neurotoxicity: Quantitative Analysis of Rat Brain Toxicity Following Exposure to Trimethyltin

The organotin, trimethyltin (TMT), is a highly toxic compound. In this study, silver-stained rat brain sections were qualitatively and quantitatively evaluated for degeneration after systemic treatment with TMT. Degenerated neurons were counted using image analysis methods available in the HALO image analysis software. Specific brain areas including the cortex, inferior and superior colliculus, and thalamus were quantitatively analyzed. Our results indicate extensive and widespread damage to the rat brain after systemic administration of TMT. Qualitative results suggest severe TMT-induced toxicity 3 and 7 days after the administration of TMT. Trimethyltin toxicity was greatest in the hippocampus, olfactory area, cerebellum, pons, mammillary nucleus, inferior and superior colliculus, hypoglossal nucleus, thalamus, and cerebellar Purkinje cells. Quantification showed that the optic layer of the superior colliculus exhibited significantly more degeneration compared to layers above and below. The inferior colliculus showed greater degeneration in the dorsal area relative to the central area. Similarly, in cortical layers, there was greater neurodegeneration in deeper layers compared to superficial layers. Quantification of damage in various thalamic nuclei showed that the greatest degeneration occurred in midline and intralaminar nuclei. These results suggest selective neuronal network vulnerability to TMT-related toxicity in the rat brain.

Wild bees as floral visitors to Salvia assurgens (Lamiaceae): a contribution to the pollination ecology of a white-flowered endemic Mexican sage

Background and Aims: Salvia assurgens (a white-flowered sage) is considered to be a melittophilous species due to its floral architecture. However, there are no current empirical data supporting its assignment to this pollination syndrome. The present study aimed to record the diurnal floral visitors of S. assurgens to confirm its characterization as melittophilous and to evaluate which species of bees are potential pollinators. Methods: We collected wild bee visitors to the flowers of one population of S. assurgens in northeastern Michoacán, Mexico, during the summers of 2018 and 2019. We analyzed the pollen loads of each bee species and body area. In addition, we recorded the behavior of some wild bees when visiting flowers of S. assurgens. Key results: Seventeen bee species from three families (Apidae, Halictidae, and Megachilidae) were recorded as floral visitors of S. assurgens. Ninety percent of pollen carried by the examined bees belonged to S. assurgens. Four species of wild bees were the most frequent visitors, with S. assurgens accounting for 94.2% of the pollen on their bodies. Notably, these species presented clear differences in the distribution of pollen on their body parts: two of them, Bombus pennsylvanicus sonorus and Megachile sp. 1 accumulated up to 90% of the pollen on the frons and dorsal area of their thorax. It is most likely that pollen is transferred from these body areas to the stigma of S. assurgens. Conclusions: The present study provides evidence of the melittophilous pollination syndrome of S. assurgens. The wild bee richness recorded in this study is as high as that previously reported in studies on floral visitors to Neotropical sages. Finally, our results highlight the usefulness of considering pollen loads to increase our knowledge of Salvia pollination ecology.

Two new species of the genus Erromenus Holmgren, 1857 (Hymenoptera: Ichneumonidae: Tryphoninae) from the Siberia and Russian Far East

Two new species, Erromenus atrator sp. n. (Primorskiy Territory) and E. tereshkini sp. n. (Zabaikalskiy Territory) are described in the tribe Trypho¬nini (Ichneumonidae). Both new species differ from other congeners by almost completely black body color and a very wide dorsal area at the base of the pro-podeum, formed by a fused basal area and areola, and by the distinctly raised upper edge of the antennal sockets. In the last character, in the structure of the clypeal foveae and of the ovipositor, the new species are evolutionarily close to the Holarctic species E. zonarius (Gravenhorst, 1820). A new subgroup of species zonarius in the marginatus species group is proposed. Key to black-colored species of zonarius species-subgroup of the Eastern Palaearctic and related species is given.

Individual identification patterns as a monitoring strategy for American crocodiles: Tayrona National Natural Park as a study case

Population numbers of the American crocodile in Colombia have shown an increasing trend during the last decades. However, the lack of monitoring programs has restricted our understanding about this species’ ecology, limiting the ability to develop sound conservation plans. We assessed the effectiveness and robustness of the Individual Identification Pattern Recognition (IIPR) method for remotely monitoring American crocodile populations based on photographs taken by researchers, tourists, locals, and employees at the Tayrona National Natural Park (TNNP). We catalogued a total of 97 events from 2008 to 2020; 34.02% of which were suitable to analyze using IIPR. We identified eight individuals across 33 events that required only 4.71 ± 1.70 transverse scute lines to obtain complete identification, with the lowest levels of variation in the post occipital and nuchal regions compared with the dorsal area. The probabilities of repeating both the most and least common patterns found in the TNNP were 1.88 × 10−6 and 1.81 × 10−12, respectively, and the probabilities of repeating the same pattern of each individual identified ranged between 48.73 × 10−11 and 15.24 × 10−8. Animals B and C were continuously identified between 2012 and 2020 along the Arrecife beach coastline, whereas animals A, H, E, and F were occasionally registered between 2008 and 2019 at the Cañaveral beach. Overall, the IIPR method looks as a promising tool for monitoring American crocodile populations in the TNNP albeit some improvements in data collection that must be done to increase the number of useful events and analysis quality.