Role of fibroblast growth factor-23 as an early marker of metabolic bone disease of prematurity.

PURPOSE: Metabolic bone disease of prematurity (MBDP) remains a significant cause of morbidity in extremely premature newborns. In high-risk patients, suspected diagnosis and subsequent treatment modifications, with limitations in terms of sensitivity and specificity, rely on low phosphorus levels and/or high levels of alkaline phosphatase (ALP). We investigated the potential of fibroblast growth factor-23 (FGF23) as an early marker for MBDP when measured at 3-4 weeks of life in at-risk patients. METHODS: A single-center prospective observational non-interventional study including preterm newborns of both sexes, with a gestational age of less than 32 weeks and/or a birth weight of less than 1500 g. In the standard biochemical screening for MBDP performed between 3 and 4 weeks of life within a nutritional profile, the determination of FGF23 was included along with other clinical and metabolic studies. The study was conducted at Marqués de Valdecilla University Hospital in Santander, Spain, from April 2020 to March 2021. Participants provided informed consent. Biochemical analyses were conducted using various platforms, and follow-up evaluations were performed at the discretion of neonatologists. Patients at high risk for MBDP received modifications in treatment accordingly. The sample was descriptively analyzed, presenting measures of central tendency and dispersion for continuous variables, and absolute numbers/percentages for categorical ones. Tests used included t-tests, Mann‒Whitney U tests, chi-square tests, logistic regressions, Pearson correlation, and ROC curve analysis (IBM SPSS Statistics version 19). Significance level: P < 0.05. RESULTS: In the study involving 25 at-risk premature newborns, it was found that 20% (n = 5) were diagnosed with MBDP. Three of these patients (60%) were identified as high-risk based on standard biochemical evaluation at 3-4 weeks of age, while the other two patients (40%) were diagnosed in subsequent weeks. However, in all 5 patients, measurement of FGF23 levels would allow for early identification and optimization of treatment before other markers become altered. Low levels of FGF23 at 3-4 weeks, even with normal phosphorus and ALP levels, indicate the need for modifications in nutritional supplementation. CONCLUSIONS: MBDP remains a significant concern in extremely premature newborns. Current diagnostic methods rely on limited biochemical markers. Early detection of low FGF23 levels enables timely interventions, potentially averting demineralization.

Maintaining the permanence principle of death during normothermic regional perfusion in controlled donation after the circulatory determination of death: Results of a prospective clinical study.

One concern about the use of normothermic regional perfusion (NRP) in controlled donation after the circulatory determination of death (cDCD) is that the brain may be perfused. We aimed to demonstrate that certain technical maneuvers preclude such brain perfusion. A nonrandomized trial was performed on cDCD donors. In abdominal normothermic regional perfusion (A-NRP), the thoracic aorta was blocked with an intra-aortic occlusion balloon. In thoracoabdominal normothermic regional perfusion (TA-NRP), the arch vessels were clamped and the cephalad ends vented to the atmosphere. The mean intracranial arterial blood pressure (ICBP) was invasively measured at the circle of Willis. Ten cDCD donors subject to A-NRP or TA-NRP were included. Mean ICBP and mean blood pressure at the thoracic and the abdominal aorta during the circulatory arrest were 17 (standard deviation [SD], 3), 17 (SD, 3), and 18 (SD, 4) mmHg, respectively. When A-NRP started, pressure at the abdominal aorta increased to 50 (SD, 13) mmHg, while the ICBP remained unchanged. When TA-NRP was initiated, thoracic aorta pressure increased to 71 (SD, 18) mmHg, but the ICBP remained unmodified. Recorded values of ICBP during NRP were 10 mmHg. In conclusion, appropriate technical measures applied during NRP preclude perfusion of the brain in cDCD. This study might help to expand NRP and increase the number of organs available for transplantation.

Bronchial Stenosis After Lung Transplantation From cDCD Donors Using Simultaneous Abdominal Normothermic Regional Perfusion: A Single-center Experience.

BACKGROUND: Controlled donation after circulatory death (cDCD) has increased the number of lung donors significantly. The use of abdominal normothermic regional perfusion (A-NRP) during organ procurement is a common practice in some centers due to its benefits on abdominal grafts. This study aimed to assess whether the use of A-NRP in cDCD increases the frequency of bronchial stenosis in lung transplant (LT) recipients. METHODS: A single-center, retrospective study including all LTs was performed between January 1, 2015, and August 30, 2022. Airway stenosis was defined as a stricture that leads to clinical/functional worsening requiring the use of invasive monitoring and therapeutic procedures. RESULTS: A total of 308 LT recipients were included in the study. Seventy-six LT recipients (24.7%) received lungs from cDCD donors using A-NRP during organ procurement. Forty-seven LT recipients (15.3%) developed airway stenosis, with no differences between lung recipients with grafts from cDCD (17.2%) and donation after brain death donors (13.3%; P = 0.278). A total of 48.9% of recipients showed signs of acute airway ischemia on control bronchoscopy at 2 to 3 wk posttransplant. Acute ischemia was an independent risk factor for airway stenosis development (odds ratio = 2.523 [1.311-4.855], P = 0.006). The median number of bronchoscopies per patient was 5 (2-9), and 25% of patients needed >8 dilatations. Twenty-three patients underwent endobronchial stenting (50.0%) and each patient needed a median of 1 (1-2) stent. CONCLUSIONS: Incidence of airway stenosis is not increased in LT recipients with grafts obtained from cDCD donors using A-NRP.

Normothermic Regional Perfusion in Pediatric Controlled Donation After Circulatory Death Can Lead to Optimal Organ Utilization and Posttransplant Outcomes.

BACKGROUND: The benefits of normothermic regional perfusion (NRP) in posttransplant outcomes after controlled donation after the determination of death by circulatory criteria (cDCD) has been shown in different international adult experiences. However, there is no information on the use of NRP in pediatric cDCD donors. METHODS: This is a multicenter, retrospective, observational cohort study describing the pediatric (<18 y) cDCD procedures performed in Spain, using either abdominal NRP or thoracoabdominal NRP and the outcomes of recipients of the obtained organs. RESULTS: Thirteen pediatric cDCD donors (age range, 2-17 y) subject to abdominal NRP or thoracoabdominal NRP were included. A total of 46 grafts (24 kidneys, 11 livers, 8 lungs, 2 hearts, and 1 pancreas) were finally transplanted (3.5 grafts per donor). The mean functional warm ischemic time was 15 min (SD 6 min)' and the median duration of NRP was 87 min (interquartile range, 69-101 min). One-year noncensored for death kidney graft survival was 91.3%. The incidence of delayed graft function was 13%. One-year' noncensored-for-death liver graft survival was 90.9%. All lung and pancreas recipients had an excellent evolution. One heart recipient died due to a septic shock. CONCLUSIONS: This is the largest experience of pediatric cDCD using NRP as graft preservation method. Although our study has several limitations, such as its retrospective nature and the small sample size, its reveals that NRP may increase the utilization of cDCD pediatric organs and offer optimal recipients' outcomes.

Lung transplantation from controlled donation after circulatory death using simultaneous abdominal normothermic regional perfusion: A single center experience.

Despite the benefits of abdominal normothermic regional perfusion (A-NRP) for abdominal grafts in controlled donation after circulatory death (cDCD), there is limited information on the effect of A-NRP on the quality of the cDCD lungs. We aimed to study the effect of A-NRP in lungs obtained from cDCD and its impact on recipients´ outcomes. This is a study comparing outcomes of lung transplants (LT) from cDCD donors (September 2014 to December 2021) obtained using A-NRP as the abdominal preservation method. As controls, all lung recipients transplanted from donors after brain death (DBD) were considered. The primary outcomes were lung recipient 3-month, 1-year, and 5-year survival. A total of 269 LT were performed (60 cDCD and 209 DBD). There was no difference in survival at 3 months (98.3% cDCD vs. 93.7% DBD), 1 year (90.9% vs. 87.2%), and 5 years (68.7% vs. 69%). LT from the cDCD group had a higher rate of primary graft dysfunction grade 3 at 72 h (10% vs. 3.4%; p <  .001). This is the largest experience ever reported with the use of A-NRP combined with lung retrieval in cDCD donors. This combined method is safe for lung grafts presenting short-term survival outcomes equivalent to those transplanted through DBD.

Chronic critical illness in polytrauma. Results of the Spanish trauma in ICU registry.

PURPOSE: Chronic critical illness after trauma injury has not been fully evaluated, and there is little evidence in this regard. We aim to describe the prevalence and risk factors of chronic critical illness (CCI) in trauma patients admitted to the intensive care unit. MATERIAL AND METHODS: Retrospective observational multicenter study (Spanish Registry of Trauma in ICU (RETRAUCI)). Period March 2015 to December 2019. Trauma patients admitted to the ICU, who survived the first 48 h, were included. Chronic critical illness (CCI) was considered as the need for mechanical ventilation for a period greater than 14 days and/or placement of a tracheostomy. The main outcomes measures were prevalence and risk factors of CCI after trauma. RESULTS: 1290/9213 (14%) patients developed CCI. These patients were older (51.2 ± 19.4 vs 49 ± 18.9); p < .01) and predominantly male (79.9%). They presented a higher proportion of infectious complications (81.3% vs 12.7%; p < .01) and multiple organ dysfunction syndrome (MODS) (27.02% vs 5.19%; p < .01). CCI patients required longer stays in the ICU and had higher ICU and overall in-hospital mortality. Age, injury severity score, head injury, infectious complications, and development of MODS were independent predictors of CCI. CONCLUSION: CCI in trauma is a prevalent entity in our series. Early identification could facilitate specific interventions to change the trajectory of this process.

Controlled Donation After Circulatory Death Using Normothermic Regional Perfusion Does Not Increase Graft Fibrosis in the First Year Posttransplant Surveillance Biopsy.

OBJECTIVES: The number of kidney transplants obtained from controlled donations after circulatory death is increasing, with long-term outcomes similar to those obtained with donations after brain death. Extraction using normothermic regional perfusion can improve results with controlled donors after circulatory death; however, information on the histological impact and extraction procedure is scarce. MATERIALS AND METHODS: We retrospectively investigated all kidney transplants performed from October 2014 to December 2019, in which a follow-up kidney biopsy had been performed at 1-year follow-up, comparing controlled procedures with donors after circulatory death and normothermic regional perfusion versus donors after brain death. Interstitial fibrosis/tubular atrophy was assessed by adding the values of interstitial fibrosis and tubular atrophy, according to the Banff classification of renal allograft pathology. RESULTS: When we compared histological data from 66 transplants with donations after brain death versus 24 transplants with donations after circulatory death and normothermic regional perfusion, no differences were found in the degree of fibrosis in the 1-year follow-up biopsy (1.7 ± 1.3 vs 1.7 ± 1.1; P = .971) or in the ratio of patients with increased fibrosis calculated as interstitial fibrosis/tubular atrophy >2 (18% vs 13%; P = .522). In our multivariate analysis, which included acute rejection, expanded criteria donation, and the type of donation, no variable was independently related to an increased risk of interstitial fibrosis/tubular atrophy >2. CONCLUSIONS: The outcomes of kidney grafts procured in our center using controlled procedures with donors after circulatory death and normothermic regional perfusion were indistinguishable from those obtained from donors after brain death, showing the same degree of fibrosis in the 1-year posttransplant surveillance biopsy. Our data support the conclusion that normothermic regional perfusion should be the method of choice for extraction in donors after circulatory death.

PlA2 Polymorphism of Platelet Glycoprotein IIb/IIIa and C677T Polymorphism of Methylenetetrahydrofolate Reductase (MTHFR), but Not Factor V Leiden and Prothrombin G20210A Polymorphisms, Are Associated with More Severe Forms of Legg-Calvé-Perthes Disease.

The possible association of common polymorphic variants related to thrombophilia (the rs6025(A) allele encoding the Leiden mutation, rs1799963(A), i.e., the G20210A mutation of the prothrombin F2 gene, the rs1801133(T) variant of the methylenetetrahydrofolate reductase (MTHFR) gene that encodes an enzyme involved in folate metabolism, and rs5918(C), i.e., the 'A2' allele of the platelet-specific alloantigen system that increases platelet aggregation induced by agonists), with the risk of Legg-Calvé-Perthes disease (LCPD) and the degree of hip involvement (Catterall stages I to IV) was analyzed in a cohort study, including 41 children of ages 2 to 10.9 (mean 5.4, SD 2.2), on the basis of clinical and radiological criteria of LCPD. In 10 of the cases, hip involvement was bilateral; thus, a total of 51 hips were followed-up for a mean of 75.5 months. The distribution of genotypes among patients and 118 controls showed no significant differences, with a slightly increased risk for LCPD in rs6025(A) carriers (OR: 2.9, CI: 0.2-47.8). Regarding the severity of LCPD based on Catterall classification, the rs1801133(T) variant of the MTHFR gene and the rs5918(C) variant of the platelet glycoprotein IIb/IIIa were associated with more severe forms of Perthes disease (Catterall III-IV) (p < 0.05). The four children homozygous for mutated MTHFR had a severe form of the disease (Stage IV of Catterall) and a higher risk of non-favorable outcome (Stulberg IV-V).

Combined lung and liver procurement in controlled donation after circulatory death using normothermic abdominal perfusion. Initial experience in two Spanish centers.

Combining simultaneously lung and liver procurement in controlled donation after circulatory death (cDCD) using normothermic abdominal perfusion (NRP) for abdominal grafts and cooling and rapid recovery technique (RR) for the lungs increases the complexity of the procurement procedure and might injure the grafts. A total of 19 cDCDs from two centers using this combined procedure were evaluated, and 16 liver and 21 lung transplantations were performed. As controls, 34 donors after brain death (DBDs) were included (29 liver and 41 lung transplantations were performed). Two cDCD liver recipients developed primary nonfunction (12.5%). No cases of ischemic cholangiopathy were observed among cDCD recipients. The 1-year and 2-year liver recipients survival was 87.5% and 87.5% for the cDCD group, and 96% and 84.5% for the DBD group, respectively (P = .496). The 1-year and 2-year lung recipients survival was 84% and 84% for the cDCD group and 90% and 90% for the DBD group, respectively (P = .577). This is the largest experience ever reported in cDCD with the use of NRP combined with RR of the lungs. This combined method offers an outstanding recovery rate and liver and lung recipients survival comparable with those transplanted with DBDs. Further studies are needed to confirm our findings.

Excellent long-term outcome with lungs obtained from uncontrolled donation after circulatory death.

We aimed to propose a simple and effective preservation method in lungs procured for transplantation from uncontrolled donation after circulatory death (uDCD) associated with excellent long-term results. Outcome measures for lung recipients were survival and primary graft dysfunction (PGD) grade 3. Survival was estimated using the Kaplan-Meier method. A total of 9 lung uDCDs were evaluated and 8 lung transplants were performed. Mean no-flow time was 9.8 minutes (standard deviation [SD] 8.6). Mean time from cardiac arrest to topical cooling was 96.8 minutes (SD 16.8). Preservation time was 159 minutes (SD 31). Ex vivo lung perfusion was used to assess lung function prior to transplantation in 2 cases. Mean recipient age was 60.8 years (SD 3.1), and mean total ischemic time was 678 minutes (SD 132). PGD grade 3 was observed in 2 cases (25%). The 1-month, 1-year, and 5-year survival rates were 100%, 87.5%, and 87.5%, respectively. Mean follow-up was 52 months. The logistic complexity of procuring lungs from uDCDs for transplantation requires the development of new strategies designed to facilitate this type of donation. A program based on strict selection criteria, using a simple and effective preservation technique, may recover lung grafts with excellent long-term posttransplant outcomes.

Risk Factors for Mortality in 272 Patients With Lung Transplant: A Multicenter Analysis of 7 Intensive Care Units.

BACKGROUND: One-year survival in lung transplant is around 85%, but this figure has not increased in recent years, in spite of technical improvements. METHODS: Retrospective, multicenter cohort study. Data from 272 eligible adults with lung transplant were recorded at 7 intensive care units (ICU) in Spain in 2013. The objective was to identify variables that might help to guide future clinical interventions in order to reducethe risk of death in the postoperative period. RESULTS: One patient (0.3%) died in the operating room and 27 (10%) within 90 days. Twenty (7.4%) died within 28 days, after a median of 14 ICU days. Grade 3 pulmonary graft dysfunction was documented in 108 patients, of whom 21 died, compared with 6 out of 163 without pulmonary graft dysfunction (P<.001). At ICU admission, non-survivors had significantly lower (P=.03) median PaO2/FiO2 (200mmHg vs 280mmHg), and the difference increased after 24hours (178 vs 297mmHg, P<.001). Thirteen required extracorporeal membrane oxygenation, and 7(53.8%) died. A logistic regression model identified pulmonary graft dysfunction (OR: 6.77), donor age>60yr (OR: 2.91) and SOFA>8 (OR: 2.53) as independent predictors of 90-day mortality. At ICU admission, higher median procalcitonin (1.6 vs 0.6) and lower median PaO2/FiO2 (200 vs 280mmHg) were significantly associated with mortality. CONCLUSION: Graft dysfunction remains a significant problem in lung transplant. Early ICU interventions in patients with severe hypoxemia or high procalcitonin are crucial in order to lower mortality.

An intensive lung donor treatment protocol does not have negative influence on other grafts: a multicentre study.

OBJECTIVES: Competing requirements for organ perfusion may call for antagonistic strategies such as fluid replacement or high positive end-expiratory pressure. We recently proposed an intensive lung donor treatment protocol that nearly tripled lung procurement rates and validated it in a multicentre study. The next step was to evaluate the impact of our proposal on the other organ grafts recovered from lung donors and on the recipients' outcome after transplantation of those grafts. METHODS: A quasi-experimental study was conducted in six Spanish hospitals during 2013 (2010-12 was historical control). Organ donor management was led by a trained and experienced intensive care staff. RESULTS: A total of 618 actual donors after brain death (DBDs) were included, 453 DBDs in the control period (annual average 151) and 165 in the protocol period. No baseline differences were found between the periods. Heart, liver, kidney and pancreas retrieval rates were similar in both periods, and heart, liver, kidney and pancreas recipients' survival at 3 months showed no differences between both periods. CONCLUSIONS: Our lung donor treatment protocol is safe for other grafts obtained from donors undergoing these procedures with the aim of increasing lungs available for transplantation. It has no negative impact on the recovery rates of other grafts or on early survival of heart, liver, pancreas or kidney recipients.

Effect of an intensive lung donor-management protocol on lung transplantation outcomes.

BACKGROUND: An intensive lung donor-management protocol based on a strict protocol would increase the lung procurement rate. The aim of this study was to determine the effect of such a protocol on the rate of lung grafts available for transplant. METHODS: A lung-management protocol for donors after brain death (DBD) was implemented in 2009. Lung donors from 2009 to 2011 were the prospective cohort, and those from 2003 to 2008 formed the historical control. We analyzed the synergic effect of several measures, such as protective ventilation, ventilator recruitment maneuvers, high positive end-expiratory pressure, fluid restriction with reduced extravascular lung water values, and hormonal resuscitation therapy in multiorgan DBD. The number of lungs available for transplantation was the main outcome measure. For recipients, early survival and the rate of primary graft dysfunction (PGD) grade 3 were the main outcome measures. RESULTS: The DBD rate was more than 40 donors per 1 million population in both periods. The rate of lung donors increased from 20.1% to 50% (p < 0.001), quadrupling the number of lung donors (p < 0.001), grafts retrieved (p = 0.02), and patients who received a lung transplant (p < 0.01). No differences were observed in the survival of early recipients (p = 0.203) or in the rate of PGD grade 3 (p = 0.835). CONCLUSION: The management of multiorgan DBDs should be approached as a global treatment requiring attentive bedside management. Implementing an intensive lung donor-management protocol based on synergic measures increases lung procurement rates, negative effect on early survival of lung recipients or PGD grade 3.

Increased numbers of circulating CD8 effector memory T cells before transplantation enhance the risk of acute rejection in lung transplant recipients.

The effector and regulatory T cell subpopulations involved in the development of acute rejection episodes in lung transplantation remain to be elucidated. Twenty-seven lung transplant candidates were prospectively monitored before transplantation and within the first year post-transplantation. Regulatory, Th17, memory and naïve T cells were measured in peripheral blood of lung transplant recipients by flow cytometry. No association of acute rejection with number of peripheral regulatory T cells and Th17 cells was found. However, effector memory subsets in acute rejection patients were increased during the first two months post-transplant. Interestingly, patients waiting for lung transplant with levels of CD8(+) effector memory T cells over 185 cells/mm(3) had a significant increased risk of rejection [OR: 5.62 (95% CI: 1.08-29.37), p=0.04]. In multivariate analysis adjusted for age and gender the odds ratio for rejection was: OR: 5.89 (95% CI: 1.08-32.24), p=0.04. These data suggest a correlation between acute rejection and effector memory T cells in lung transplant recipients. The measurement of peripheral blood CD8(+) effector memory T cells prior to lung transplant may define patients at high risk of acute lung rejection.

Impact of restrictive fluid balance focused to increase lung procurement on renal function after kidney transplantation.

BACKGROUND: Restrictive management of fluid status has been proposed to increase the rates of lung grafts available for transplant. However, no studies have supported the effect of this negative fluid balance in the kidney graft recipients. METHODS: We evaluated the effect of restrictive fluid balance in brain-dead donors and their impact in 404 kidney recipients using Kaplan-Meier curves and Cox regression for long-term effects, and logistic regression for short-term effects. Our primary interest was graft survival and the second was occurrence of delayed graft function (DGF). RESULTS: A negative or equalized fluid balance with a central venous pressure (CVP) <6 mm Hg affects neither graft survival in kidney recipients (P = 0.983) nor the development of DGF (P = 0.573). A positive fluid balance between brain death and organ retrieval does not reduce either the risk of graft survival or the risk of DGF. CONCLUSION: We concluded that restrictive management of fluid balance in a multiorgan donor supports adequate perfusion to vital organ systems even with a CVP <6 mm Hg. A strict fluid balance could avoid volume overload and lung neurogenic oedema, increasing the rate of lung grafts available for transplant without impacting either kidney graft survival or DGF development.

Tracheal rupture after endotracheal intubation: a literature systematic review.

We aim to perform a systematic review and meta-analysis of the cases of postintubation tracheal rupture (PiTR) published in the literature, with the aim of determining the risk factors that contribute to tracheal rupture during endotracheal intubation. A further objective has been to determine the ideal treatment for this condition (surgical repair or conservative management). A MEDLINE review of cases of tracheal rupture after intubation published in the English language and a review of the references in the articles found. The articles included were those that reported at least the demographic data (age and sex), the treatment performed, and the outcome. Those papers that did not detail the above variables were excluded. The search found 50 studies that satisfied the inclusion criteria. These studies included 182 cases of postintubation tracheal rupture. The overall mortality was 22% (40 patients). A statistical analysis was performed determining the relative risk (RR), 95% confidence intervals (95% CI) and/or statistical significance. The analysis was performed on the overall group and after dividing into 2 subgroups: patients in whom the lesion was detected intraoperatively, and other patients. Patient age (p=0.015) and emergency intubation (RR=3.11; 95% CI, 1.81-5.33; p=0.001) were variables associated with an increased mortality. In those patients in whom the PiTR was detected outside the operating theatre (delayed diagnosis), emergency intubation (RR=3.05; 95% CI, 1.69-5.51; p<0.0001), the absence of subcutaneous emphysema (RR=2.17; 95% CI, 1.25-4; p=0.001), and surgical treatment (RR=2.09; 95% CI, 1.08-4.07; p=0.02) were associated with an increased mortality. In addition, age (p=0.1) and male gender (RR=1.89; 95% CI, 0.98-3.63; p=0.13) showed a clear trend towards an increased mortality. PiTR is an uncommon condition but carries a high morbidity and mortality. Emergency intubation is the principal risk factor, increasing the risk of death threefold compared to elective intubation. Conservative treatment is associated with a better outcome. However, the group of patients who would benefit from surgical treatment has not been fully defined. Further studies are required to evaluate the best treatment options.

Hippocampus, aging, and segregating memories.

Rats use time-of-day cues to modulate learned taste aversion memories. If adult rats are accustomed to drinking saline in the evening and they receive a lithium chloride injection after drinking saline in the morning, they form a stronger aversion to saline than rats that were conditioned after drinking saline at the familiar time. The difference indicated that the rats formed segregated representations of saline taste and the time of day the saline was consumed. This was inferred because the modulation of learning by time of day was observed when the aversions were tested at the familiar evening drinking time. If the rats had formed a compound representation of saline taste and the time of day it was consumed, the opposite pattern of differences would be expected. We used this modulation of learning by time of day to assay whether aged rats have an impaired ability to form segregated representations of experience. We find that aged rats had similar saline aversions if they were conditioned at either the familiar or the unfamiliar time of day. Furthermore, dorsal hippocampal lesions affecting also the overlying parietal cortex in the aged rats caused greater saline aversions if the rats were conditioned after drinking saline at the familiar time of day. This indicated that aged rats are aware of the time of day but after the lesion, they act as if they do not segregate saline taste from the time of day it was consumed. The results suggest that the ability to form segregated representations of a complex experience is impaired in aging and abolished by hippocampal lesions.

Cerebral apoptosis in severe traumatic brain injury patients: an in vitro, in vivo, and postmortem study.

One of the most important recent observations in traumatic brain injury (TBI) relates to the potential role of apoptosis in secondary brain injury. We aimed to analyze the presence of apoptosis and the expression of apoptosis-related proteins in brain samples from patients with TBI. We also tried to find any association between the in situ results and the in vitro observations in a neuronal model of induced-apoptosis. Brain tissue from the pericontusional zone (PCZ) of patients with traumatic contusions and from post-mortem samples was analyzed. Immunohistochemical analyses of apoptosis-related proteins and the terminal deoxynucleotide transferase-mediated nick end labeling (TUNEL) method to determine the presence of apoptotic cells were performed. Apoptotic rates on neuronal cells induced by jugular bulb vein sera was determined by flow cytometry. TUNEL-positive cells were detected in all PCZ of traumatic contusions and in most of PCZ in post-mortem specimens (none in control; p = 0.026). In vivo samples showed higher expression of antiapoptotic proteins Bcl-2 (p = 0.027) and Bcl-XL (p = 0.014) than post-mortem samples. In autopsies, the expression of Fas and Bim (p < 0.05) were higher in PCZ than in the zone distal from the contusion. In vitro studies showed that apoptotic rate was an independent factor associated with mortality at 6 months (p = 0.014). In the receiving operator curve (ROC) curve, a cut-off point of 66.5% showed a sensitivity of 89.5% and specificity of 66.7% in the prediction of patients' death. Cerebral apoptosis is a prominent form of cell death in the PCZ of human traumatic cerebral contusions, and high rates of in vitro apoptosis are associated with a poorer prognosis after TBI.