Differential frontal alpha oscillations and mechanisms underlying loss of consciousness: a comparison between slow and fast propofol infusion rates.

Mechanisms underlying loss of consciousness following propofol administration remain incompletely understood. The objective of this study was to compare frontal lobe electroencephalography activity and brainstem reflexes during intravenous induction of general anaesthesia, in patients receiving a typical bolus dose (fast infusion) of propofol compared with a slower infusion rate. We sought to determine whether brainstem suppression ('bottom-up') predominates over loss of cortical function ('top-down'). Sixteen ASA physical status-1 patients were randomly assigned to either a fast or slow propofol infusion group. Loss of consciousness and brainstem reflexes were assessed every 30 s by a neurologist blinded to treatment allocation. We performed a multitaper spectral analysis of all electroencephalography data obtained from each participant. Brainstem reflexes were present in all eight patients in the slow infusion group, while being absent in all patients in the fast infusion group, at the moment of loss of consciousness (p = 0.010). An increase in alpha band power was observed before loss of consciousness only in participants allocated to the slow infusion group. Alpha band power emerged several minutes after the loss of consciousness in participants allocated to the fast infusion group. Our results show a predominance of 'bottom-up' mechanisms during fast infusion rates and 'top-down' mechanisms during slow infusion rates. The underlying mechanisms by which propofol induces loss of consciousness are potentially influenced by the speed of infusion.

Recomendación Clínica: "Recomendaciones para el manejo de pacientes con COVID-19 con indicación terapéutica de ventilación mecánica que eventualmente son conectados a máquinas de anestesia" / Recommendations for patient management with COVID-19 with therapeutic indication mechanical ventilation that eventually are connected to anesthesia machines

La pandemia de COVID-19 producida por SARS-CoV-2 actualmente en curso anticipa una gran demanda por ventiladores mecánicos (VM), ya que un porcentaje relevante de los contagiados cae rápidamente en insuficiencia respiratoria y requiere de cuidados intensivos. Anticipándose a ese exceso de demanda y considerando que es muy probable que el número actual de ventiladores mecánicos en las unidades de cuidados intensivos (UCI) sean insuficientes, se ha solicitado a la SACH un informe técnico en relación al uso de las máquinas de anestesia como VM.

Recomendaciones para el manejo de pacientes con COVID19 en el perioperatorio / Recommendations for the management of patients with COVID19 in the perioperative period

En diciembre de 2019, una serie de casos de neumonía de causa desconocida surgieron en Wuhan, Hubei, China, con presentaciones clínicas muy parecidas a la neumonía viral. El análisis de secuenciación profunda de muestras del tracto respiratorio inferior indicó un nuevo coronavirus, que se denominó nuevo coronavirus 2019 (2019-nCoV o SARS-CoV2) [15]. La propagación del virus ha sido extremadamente rápida, tanto así que el 11 de marzo de 2020 y luego de más de 118.000 infectados en 114 países con 4.300 fallecidos a esa fecha, la organización mundial de la salud declaró a la enfermedad COVID-19, causada por 2019-nCoV, como una pandemia.

Odor response properties of neighboring mitral/tufted cells in the rat olfactory bulb.

Olfactory perception initiates in the nasal epithelium wherefrom olfactory receptor neurons--expressing the same receptor protein--project and converge in two different glomeruli within each olfactory bulb. Recent evidence suggests that glomeruli are isolated functional units, arranged in a chemotopic manner in the olfactory bulb. Exposure to odorants leads to the activation of specific populations of glomeruli. In rodents, about 25-50 mitral/tufted cells project their primary dendrites to a single glomerulus receiving similar sensory input. Yet, little is known about the properties of neighboring mitral/tufted cells connected to one or a few neighboring glomeruli. We used tetrodes to simultaneously record multiple single-unit activity in the mitral cell layer of anesthetized, freely breathing rats while exposed to mixtures of chemically related compounds. First, we characterized the odorant-induced modifications in firing rate of neighboring mitral/tufted cells and found that they do not share odorant response profiles. Individual units showed a long silent (11.01 ms) period with no oscillatory activity. Cross-correlation analysis between neighboring mitral/tufted cells revealed negligible synchronous activity among them. Finally, we show that respiratory-related temporal patterns are dissimilar among neighboring mitral/tufted cells and also that odorant stimulation results in an individual modification that is not necessarily shared by neighboring mitral/tufted cells. These results show that neighboring mitral/tufted cells frequently exhibit dissimilar response properties, which are not consistent with a precise chemotopic map at the mitral/tufted cell layer in the olfactory bulb.

Sweet lupin protein quality in young men.

The protein quality of Lupinus albus cv Multolupa was evaluated in young adult males using the nitrogen balance technique at graded levels of N intake, and compared with egg protein. Lupin protein was consumed at levels of 0.4, 0.6 and 0.8 g/(kg.d) and egg protein at 0.3, 0.45 and 0.6 g/(kg.d). Each period started with 1 d of consuming a protein-free diet; the next 6 d were used as adaptation and the last 4 d for balance. The levels of protein intake were randomly assigned by a modified Latin square. Energy intake was individually adjusted. Mean apparent N digestibility values of lupin protein were 78.8, 76.1 and 70.2% for the levels of 0.8, 0.6 and 0.4 g protein(kg.d), respectively, and 83.8, 78.3 and 67.1% for egg protein consumed at levels of 0.6, 0.45 and 0.3 g protein/(kg.d), respectively. The N balance results obtained when subjects consumed lupin were 16.4, 0.2 and -15.1 mg N/(kg.d) for protein intakes of 0.8, 0.6 and 0.4 g/(kg.d), respectively. Those obtained for egg consumption were 12.6, -3.6 and -17.1 mg N/(kg.d) for protein intakes of 0.6, 0.45 and 0.3 g/(kg.d), respectively. The linear regressions of intake and absorbed N to retained N for lupin were: N retained = -43.41 + 0.50 N intake and N retained = -36.30 + 0.53 N absorbed. The corresponding regressions for egg were: N retained = -45.0 + 0.65 N intake and N retained = -30.65 + 0.58 N absorbed. The net protein utilization of lupin was 77% that of egg protein.

[The effect of extrusion on the acceptability and digestibility of diets for growing dogs]. / Efecto de la extrusión sobre la aceptabilidad y digestibilidad de dietas para perros en crecimiento.

Eight German Shepherd pups, about 75 days old and a live weight of 11 kg at the beginning of the trial, were used to assay a diet formulated according to NRC, 1985 (Nutrient Requirements of Dogs). The diet was administered either pelletized (PD) or extruded (ED). Acceptability was evaluated through a cafeteria test, and diet utilization by a digestion trial, wherein dry matter (DM), crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen-free extract (NFE), energy (E), Ca and P were considered. At the beginning and at the end of the digestibility trial, venous blood samples were obtained to run biochemical profiles. Results of the cafeteria test showed that extrusion-cooking improved significantly (P greater than 0.01) diet consumption, which for the ED was 512 and for the PD, 253 g/animal/day. Extrusion also improved significantly (P less than 0.01), the digestibility of DM, CP, EE, NFE and E, reaching values of 82.6, 75.2, 83.9, 90.8 and 83.6% for ED, and 68.0, 64.6, 76.7, 73.5 and 69.7 for PD, respectively. For CF, Ca and P, there was no effect (P greater than 0.05) of extrusion over digestibility. The biochemical profiles, only exhibited minor changes, all figures being considered within the normal range for puppies. It is concluded that extrusion-cooking significantly improves acceptability and biological utilization of normal diets for dogs.

[Plasma zinc and copper in infants with protein-calorie malnutrition]. / Zinc y cobre plasmáticos en lactantes con desnutrición proteínico-energética.

Forty-five marasmic infants were studied for plasma zinc and copper levels. They were selected from those children admitted to a nutritional recovery center. The mean plasma zinc level was 92.4 +/- 24 micrograms/dl (mean +/- SD); 7% of the infants had low zinc values as defined by zinc less than 70 micrograms/dl. Median copper was 90 micrograms/dl (range 27-172) and 49% of the children had copper levels below 90 micrograms/dl (established as our normal limit). Birth weight, breast feeding and prior hospitalization for acute diarrhea with dehydration were studied as antecedents related to low Cu and Zn. Children with prior diagnosis of acute diarrhea and hospitalization had lower copper levels than those sent from primary care centers. Breast feeding was associated with higher Cu levels. No relationship was found between zinc levels and those antecedents, but differences were found in regard to the degree of malnutrition, season of the year and Zn status. In this investigation no Zn deficiency was found in marasmus cases. Hypocupremia, however, is a very significant problem in marasmic infants, especially when associated with early weaning and the presence of previous hospitalization for acute diarrhea.

Safety evaluation of sweet lupine (Lupinus albus cv. Multolupa). II. Nine-month feeding and multigeneration study in rats.

Sweet lupine Lupinus albus cv. Multolupa) flour containing 41.7% protein and 0.025% lupanine was fed for 9 months to two generations of rats (F1 and F2) at a level that provided 20% dietary protein. The diets were supplemented with 0.2% DL-methionine. The control diet provided the same dietary protein level from defatted soya-bean flour, fish meal and dried skimmed milk. The lupine diet had no effect on the general condition, mortality or behaviour of the animals. The growth rate of males fed sweet lupine was significantly higher than that of the controls. Haematological parameters and tests of liver function were normal in all treatment groups. At autopsy there were no significant changes in the weight of the heart, kidney, spleen, brain and gonads. However, the relative weight of the liver of lupine-fed rats was significantly lower than that in the controls. The histology of the liver, like that of the other organs examined, was normal. The reproduction study did not reveal any adverse effect on fertility or lactation that could be attributed to ingestion of sweet lupine. This investigation did not disclose any deleterious effects through two generations of rats that were fed sweet lupine at a level that provided 20% dietary protein for 9 months.

Controlled trial of copper supplementation during the recovery from marasmus.

To evaluate copper nutritional status and the effect of a Cu supplement during recuperation, 27 marasmic infants were selected on admission to the nutrition recovery center at the Instituto de Nutrición y Tecnología de los Alimentos. Thirteen infants received 80 micrograms/kg/day of copper supplement as sulphate and the remaining a placebo. They were paired by birth weight, age, and sex. Anthropometric indices, complete blood count, ceruloplasmin, and Cu were measured on admission and at monthly intervals. Superoxide dismutase activity was measured in hypocupremic infants and was found to be low. The mean +/- SE Cu levels on admission were 127 +/- 10 micrograms/dl for the supplemented group and 137 +/- 10 micrograms/dl for the control. We found an increase in plasma Cu to 159 and 162 micrograms/dl on days 30 and 60 in the supplement group, and a significant decrease after day 30 in the placebo group. The ceruloplasmin levels followed this trend. Hypocupremia was found in 30% of the placebo group and none in the supplement group. The placebo group had a significantly higher prevalence of severe lower respiratory infections. It is concluded that a significant proportion of marasmic infants fed a milk-based diet present, during recovery, biochemical evidence of Cu deficiency. Supplementation with Cu is suggested.