Protocolized Brain Oxygen Optimization in Subarachnoid Hemorrhage.

Brain tissue hypoxia (P <sub>bt</sub> O <sub>2</sub> < 20 mmHg) is common after subarachnoid hemorrhage (SAH) and associated with poor outcome. Recent data suggest that brain oxygen optimization is feasible and reduces the time spent with P <sub>bt</sub> O <sub>2</sub> < 20 mmHg from 45 to 16% in patients with severe traumatic brain injury. Here, we intended to quantify the brain tissue hypoxia burden despite implementation of a protocolized treatment approach in poor-grade SAH patients and to identify the simultaneous occurrence of pathologic values potentially amenable to treatment. We present a bi-centric observational cohort study including 100 poor-grade SAH patients admitted to two tertiary care centers who underwent multimodal brain monitoring and were managed with a P <sub>bt</sub> O <sub>2</sub> -targeted protocolized approach. P <sub>bt</sub> O <sub>2</sub> optimization (≥ 20 mmHg) included a stepwise neuro-intensive care approach, aiming to prevent low cerebral perfusion pressure (CPP), and blood hemoglobin, and to keep normocapnia, normoxemia, and normothermia. Based on routine blood gas analysis, hemoglobin, PaCO <sub>2,</sub> and PaO <sub>2</sub> data were matched to 2-h averaged data of continuous CPP, P <sub>bt</sub> O <sub>2</sub> , core temperature, and to hourly cerebral microdialysis (CMD) samples over the first 11 days. Patients had a Glasgow Coma Scale of 3 (IQR 3-4) and were 58 years old (IQR 48-66). Overall incidence of brain tissue hypoxia was 25%, which was not different between both sites despite differences in the treatment approach. During brain tissue hypoxia, episodes of CPP < 70 mmHg (27%), PaCO <sub>2</sub> < 35 mmHg (19%), PaO <sub>2</sub> < 80 mmHg (14%), Hb < 9 g/dL (11%), metabolic crisis (CMD-lactate/pyruvate ratio > 40, and CMD-glucose < 0.7 mmol/L; 7%), and temperature > 38.3 °C (4%) were common. Our results demonstrate that brain tissue hypoxia remains common despite implementation of a P <sub>bt</sub> O <sub>2</sub> -targeted therapy in poor-grade SAH patients, suggesting room for further optimization

Revised karyotype of Alouatta caraya (Primates: Platyrrhini) based on synaptonemal complex and banding analyses

Most primates studied have the usual XX/XY sex-chromosome system. However, exceptions to this rule among howler monkeys have been suggested by several authors. Recently a quadrivalent was discovered in male meiosis of Alouatta caraya and it was established that this species has an X1X2Y1Y2 sex chromosome system. On that basis, a cytogenetic analysis of 25 males of this species is described. showing the corrected karyotype of this species. Each chromosome involved in the particular sex-chromosome system of this species is identified on the basis of mitotic chromosome measurements. G and C-banding patterns as well as on the relative measurements of synaptonemal complexes. It is now established that A. caraya has a karyotype with 2n = 52 in both sexes, and that the male one shows a single autosome 7 (X2) besides the X (X1) and the two products of the reciprocal translocation between the second autosome #7 and the Y chromosome (Y1 and Y2), while females show a homomorphic pair #7 (X2) and a pair of X1. The evolutionary implications of the exceptional primate species having composite sex-chromosome systems are discussed.Fil:Mudry, M.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Gorostiaga, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina