Disentangling functional trait variation and covariation in epiphytic lichens along a continent-wide latitudinal gradient.

Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait-environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.

Changes in tree resistance, recovery and resilience across three successive extreme droughts in the northeast Iberian Peninsula.

Understanding which variables affect forest resilience to extreme drought is key to predict future dynamics under ongoing climate change. In this study, we analyzed how tree resistance, recovery and resilience to drought have changed along three consecutive droughts and how they were affected by species, tree size, plot basal area (as a proxy for competition) and climate. We focused on the three most abundant pine species in the northeast Iberian Peninsula: Pinus halepensis, P. nigra and P. sylvestris during the three most extreme droughts recorded in the period 1951-2010 (occurred in 1986, 1994, and 2005-2006). We cored trees from permanent sample plots and used dendrochronological techniques to estimate resistance (ability to maintain growth level during drought), recovery (growth increase after drought) and resilience (capacity to recover pre-drought growth levels) in terms of tree stem basal area increment. Mixed-effects models were used to determine which tree- and plot-level variables were the main determinants of resistance, recovery and resilience, and to test for differences among the studied droughts. Larger trees were significantly less resistant and resilient. Plot basal area effects were only observed for resilience, with a negative impact only during the last drought. Resistance, recovery and resilience differed across the studied drought events, so that the studied populations became less resistant, less resilient and recovered worse during the last two droughts. This pattern suggests an increased vulnerability to drought after successive drought episodes.

What is the frequency of anatomical variations and pathological findings in maxillary sinuses among patients subjected to maxillofacial cone beam computed tomography? A systematic review.

BACKGROUND: When considering dental implant rehabilitation in atrophic posterior sectors, the maxillary sinuses must be evaluated in detail. Knowledge of the anatomical variations and of the potential lesions found in these structures conditions the outcome of sinus lift procedures and therefore of the dental implants. A systematic review is made to determine the frequency of anatomical variations and pathological findings in maxillary sinuses among patients subjected to cone beam computed tomography (CBCT). MATERIAL AND METHODS: A PubMed (MEDLINE) literature search was made of articles published up until 20 December 2015. The systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The quality of the studies included in the review was assessed using the Methodological Index for Nonrandomized Studies (MINORS). RESULTS: The combinations of search terms resulted in a list of 3482 titles. Twenty-three studies finally met the inclusion criteria and were entered in the systematic review, comprising a total of 11,971 patients. The most common anatomical variations were pneumatization and sinus septa. The prevalence of maxillary sinus disease ranged from 7.5% to 66%. The most common pathological findings of the maxillary sinus were mucosal thickening, sinusitis and sinus opacification. CONCLUSIONS: Although the main indication of CBCT of the maxillary sinus in dentistry is sinus floor elevation/treatment planning and evaluation prior to dental implant placement, this imaging modality is increasingly also used for endodontic and periodontal purposes. There is no consensus regarding the cutoff point beyond which mucosal thickening of the maxillary sinus should be regarded as pathological, and the definition of maxillary sinusitis moreover varies greatly in the scientific literature. In this regard, international consensus is required in relation to these concepts, with a clear distinction between healthy and diseased maxillary sinuses.

Thrombotic Event Prevention in Patients Undergoing Posterior Lumbar Arthrodesis: our experiencie. A retrospective case series study. / Prevención de eventos trombóticos en pacientes sometidos a cirugía de artrodesis lumbar por vía posterior: experiencia en nuestro centro. Estudio retrospectivo de casos.

INTRODUCTION: There is no generalized consensus regarding perioperative prophylaxis of venous thromboembolism (VTE), either on using or timing it in patients undergoing spine surgery. VTE is a current concern because, even though being an uncommon event, it can cause serious complications. The aim of the present study is to propose guidelines for the prevention of thrombotic events in posterior spinal surgery, either as deep vein thrombosis or pulmonary thromboembolism. If the number of patients getting prophylaxis drugs is reduced a subsequent reduction of the incidence of epidural hematoma can be expected. MATERIALS AND METHODS: A number of 235 patients who had undergone posterior spinal arthrodesis in the previous five years were studied. Mechanical thromboprophylaxis measures consisting of compression stockings were applied in all of them. Anticoagulant drugs were also applied whenever risk factors for thrombosis were observed. Early weight-bearing was resumed immediately after surgery. Demographic, clinical, and surgical variables were collected, as well as complications appearing during the follow-up period, that was scheduled at one, two, four, six and twelve months after the surgery. Thrombotic events, if present, were diagnosed by clinical and imaging tests such as ultrasound and CT angiography. RESULTS: From the total 235 patients of this series, one hundred and fifty-three cases met the study inclusion criteria. A total of four thrombotic events appeared, one in the form of deep vein thrombosis and other three in the form of pulmonary thromboembolism. These last patients suffering an embolism died because of it. None of the variables studied had statistical significance for the occurrence of a thrombotic event. All four patients who suffered thrombotic events were receiving anticoagulant drugs, in addition to mechanical compression stockings, because of the presence of risk factors for thrombosis. CONCLUSIONS: By applying the fore mentioned protocol, adequate prevention of thromboembolic events was achieved in this study population of patients undergoing posterior spinal surgery.

Carbon reserves and canopy defoliation determine the recovery of Scots pine 4 yr after a drought episode.

• Severe drought may increase physiological stress on long-lived woody vegetation, occasionally leading to mortality of overstory trees. Little is known about the factors determining tree survival and subsequent recovery after drought. • We used structural equation modeling to analyse the recovery of Scots pine (Pinus sylvestris) trees 4 yr after an extreme drought episode occurred in 2004-2005 in north-east Spain. Measured variables included the amount of green foliage, carbon reserves in the stem, mistletoe (Viscum album) infection, needle physiological performance and stem radial growth before, during and after the drought event. • The amount of green leaves and the levels of carbon reserves were related to the impact of drought on radial growth, and mutually correlated. However, our most likely path model indicated that current depletion of carbon reserves was a result of reduced photosynthetic tissue. This relationship potentially constitutes a feedback limiting tree recovery. In addition, mistletoe infection reduced leaf nitrogen content, negatively affecting growth. Finally, successive surveys in 2009-2010 showed a direct association between carbon reserves depletion and drought-induced mortality. • Severe drought events may induce long-term physiological disorders associated with canopy defoliation and depletion of carbon reserves, leading to prolonged recovery of surviving individuals and, eventually, to delayed tree death.

Diagnosis of CADASIL disease in normotensive and non-diabetics with lacunar infarct.

BACKGROUND: CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy) is characterized by recurrent cerebral ischemic episodes of the lacunar subtype usually without traditional vascular risk factors. We investigated the frequency of CADASIL among selected patients with cerebral ischemia of the lacunar subtype. METHODS: we studied patients under 65 years old who presented cerebral ischemia of the lacunar subtype without hypertension, diabetes mellitus or other causes that explained the cerebral ischemia. On the skin biopsies, we performed immunostaining analysis on 5µm frozen sections with monoclonal antibody anti-Notch 3 (1E4). We also performed a genetic analysis of the Notch 3 gene (exons 3,4,5,6,11 and 19). RESULTS: of 1.519 patients analyzed, only 57 (3.7%) fulfilled the selection criteria, and 30 of them accepted to participated in the study. We studied 30 patients, mean age was 53 years (range 34 to 65), 50% were men and all patients suffered a lacunar stroke. Immunostaining analysis was positive in two patients (6.6%) and the genetic analysis confirmed a mutation characteristic of CADASIL in exon 4 nt 622C/T (Arg 182 Cys) and 694 T/C (Cys206Arg) respectively. CONCLUSIONS: CADASIL disease was present in 6.6% of patients younger than 65 years with a lacunar stroke and without hypertension or diabetes mellitus. Screening for CADASIL should be considered in these patients.

[Aneurysmal subarachnoid hemorrhage: group of study of cerebrovascular pathology of the Spanish society of neurosurgery management guideline]. / Hemorragia subaracnoidea aneurismática: guía de tratamiento del grupo de patología vascular de la sociedad Española de neurocirugía.

An actualized revision of the most important aspects of aneurismal subarachnoid hemorrhage is presented from the guidelines previously published by the group of study of cerebrovascular pathology of the Spanish Society of Neurosurgery. The proposed recommendations should be considered as a general guide for the management of this pathological condition. However, they can be modified, even in a significant manner according to the circumstances relating each clinical case and the variations in the therapeutic and diagnostic procedures available in the center attending each patient.

[Primary decompressive craniectomy in patients with aneurysmatic subarachnoid hemorrhage. Results of a pilot study in 11 cases]. / Craniectomía descompresiva primaria en la hemorragia subaracnoidea aneurismática. Resultados deun estudio piloto en 11 casos.

INTRODUCTION: Despite the scientific and technical advances of recent years, aneurysmal subarachnoid hemorrhage (aSAH) continues to present a high morbidity and mortality. This fact, together with the impressive results of the primary decompressive craniotomy (PDC) in the malignant infarction of the middle cerebral artery suggests a possible beneficial effect of decompressive technique in aSAH. We present our experience of a pilot study that PDC was used in patients with poorgrade aSAH with associated intracerebral hematoma. PATIENTS AND METHODS: Between March 1st, 2002 and 31st April, 2008, 342 patients with aneurysmatic subarachnoid hemorrhage (aSAH) were treated at our hospital. Of these, 64 had a poor neurological grade (scores of 4 or 5 of the World Federation of Neurosurgical Societies) at the time of admission. The present study examines 11 of those patients who underwent PDC, which is performed in the same clipping and / or evacuation of an associated hematoma. RESULTS: In three patients PDC was performed after endovascular aneurysm treatment because of the need to evacuate an associated hematoma. In the eight remaining patients, PDC was performed in the same clipping and evacuation of the associated hematoma. Outcome evaluation of these eleven patients was conducted 1 year after the operation assessed by the Glasgow Outcome Scale. Six patients survived, and four of them with good results. The PDC was effective in controlling intracranial pressure in all six surviving patients. However, two of these six patients had unfavorable outcomes. Of the five who didn't survive, one patient died from a delayed epidural-subgaleal hematoma as a complication of the decompressive technique, and the other four patients died because of refractory intracranial hypertension. CONCLUSIONS: Primary DC may be beneficial in selected subgroups of patients with poor-grade aSAH. However, there is a lack of definitive evidence to support a clear recommendation for its use.

Idiopathic subarachnoid hemorrhage: a multicentre series of 220 patients.

BACKGROUND. The Spanish neurosurgical society created a multicentre data base on spontaneous SAH to analyze the real problematic of this disease in our country. This paper focuses on the group of patients with idiopathic SAH (ISAH). METHODS. 16 participant hospitals collect their spontaneous SAH cases in a common data base shared in the internet through a secured web page, considering clinical, radiological, evolution and outcome variables. The 220 ISAH cases collected from November 2004 to November 2007 were statistically analyzed as a whole and divided into 3 subgroups depending on the CT blood pattern (aneurysmal, perimesencephalic, or normal). RESULTS. The 220 ISAH patients constitute 19% of all 1149 spontaneous SAH collected in the study period. In 46,8% of ISAH the blood CT pattern was aneurysmal, which was related to older age, worse clinical condition, higher Fisher grade, more hydrocephalus and worse outcome, compared to perimesencephalic (42.7%) or normal CT (10.4%) pattern. Once surpassed the acute phase, outcome of ISAH patients is similarly good in all 3 ISAH subgroups, significantly better as a whole compared to aneurysmal SAH patients. The only variable related to outcome in ISAH after a logistic regression analysis was the admission clinical grade. CONCLUSIONS. ISAH percentage of spontaneous SAH is diminishing in Spain. Classification of ISAH cases depending on the blood CT pattern is important to differentiate higher risk groups although complications are not negligible in any of the ISAH subgroups. Neurological status on admission is the single most valuable prognostic factor for outcome in ISAH patients.

Hydraulic adjustment of Scots pine across Europe.

* The variability of branch-level hydraulic properties was assessed across 12 Scots pine populations covering a wide range of environmental conditions, including some of the southernmost populations of the species. The aims were to relate this variability to differences in climate, and to study the potential tradeoffs between traits. * Traits measured included wood density, radial growth, xylem anatomy, sapwood- and leaf-specific hydraulic conductivity (K(S) and K(L)), vulnerability to embolism, leaf-to-sapwood area ratio (A(L) : A(S)), needle carbon isotope discrimination (Delta13C) and nitrogen content, and specific leaf area. * Between-population variability was high for most of the hydraulic traits studied, but it was directly associated with climate dryness (defined as a combination of atmospheric moisture demand and availability) only for A(L) : A(S), K(L) and Delta13C. Shoot radial growth and A(L) : A(S) declined with stand development, which is consistent with a strategy to avoid exceedingly low water potentials as tree size increases. In addition, we did not find evidence at the intraspecific level of some associations between hydraulic traits that have been commonly reported across species. * The adjustment of Scots pine's hydraulic system to local climatic conditions occurred primarily through modifications of A(L) : A(S) and direct stomatal control, whereas intraspecific variation in vulnerability to embolism and leaf physiology appears to be limited.

Blood pressure is not associated with haematoma enlargement in acute intracerebral haemorrhage.

BACKGROUND AND PURPOSE: We performed an observational study that compared baseline and subsequent blood pressure (BP) measurements and its association with haematoma enlargement (HE) in patients with intracerebral haemorrhage (ICH). METHODS: We prospectively studied consecutive patients with supratentorial spontaneous ICH within the first 6 h after the onset of symptoms. HE was defined as an increase >or=33% in the volume of haematoma on the CT obtained 24-48 h after the onset of symptoms as compared with the CT at admission. We recorded systolic BP (SBP), diastolic BP (DBP) and mean BP (MBP) at admission and at 6, 12, 18 and 24 h after onset; the maximum SBP, DBP and MBP during the study period; the maximum SBP and DBP within intervals; the mean of all BP readings; administration of antihypertensive agents. RESULTS: We studied 60 patients whose mean age was 72.1 +/- 11.3 years. HE was observed in 27 (45%) patients. No statistically significant differences were observed in any of the analyses that compared BP parameters between the HE and non-HE groups (two-way anova). CONCLUSIONS: In an exploratory analysis, we did not find an association between BP and HE within the first 24 h after an acute ICH.

[Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. / Detección de episodios de hipoxia tisular isquémica mediante la monitorizaciónneurofisiológica intraoperatoria combinada con la monitorización de la oxigenacióntisular en la cirugía aneurismática.

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somatosensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. CLINICAL CASE: We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. CONCLUSIONS: The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form of early detection of ischemic phenomena caused by bad positioning of the surgical clip.

Variation in xylem vulnerability to embolism in European beech from geographically marginal populations.

Climate change is expected to increase the frequency and intensity of droughts and heatwaves in Europe, leading to effects on forest growth and major forest dieback events due to hydraulic failure caused by xylem embolism. Inter-specific variability in embolism resistance has been studied in detail, but little is known about intra-specific variability, particularly in marginal populations. We evaluated 15 European beech populations, mostly from geographically marginal sites of the species distribution range, focusing particularly on populations from the dry southern margin. We found small, but significant differences in resistance to embolism between populations, with xylem pressures causing 50% loss of hydraulic conductivity ranging from -2.84 to -3.55 MPa. Significant phenotypic clines of increasing embolism resistance with increasing temperature and aridity were observed: the southernmost beech populations growing in a warmer drier climate and with lower habitat suitability have higher resistance to embolism than those from Northern Europe growing more favourable conditions. Previous studies have shown that there is little or no difference in embolism resistance between core populations, but our findings show that marginal populations have developed ways of protecting their xylem based on either evolution or plasticity.

Plant size, not age, regulates growth and gas exchange in grafted Scots pine trees.

We studied the effect of scion donor-tree age on the physiology and growth of 6- to 7-year-old grafted Scots pine (Pinus sylvestris L.) trees (4 and 5 years after grafting). Physiological measurements included photosynthethetic rate, stomatal conductance, transpiration, whole plant hydraulic conductance, needle nitrogen concentration and carbon isotope composition. Growth measurements included total and component biomasses, relative growth rates and growth efficiency. Scion donor trees ranged in age from 36 to 269 years at the time of grafting. Hydraulic conductance was measured gravimetrically, applying the Ohm's law analogy, and directly, with a high-pressure flow meter. We found no effect of scion donor-tree age on any of the variables measured. There was, however, great variation within scion donor-tree age groups, which was related to the size of the grafted trees. Differences in size may have been caused by variable initial grafting success, but there was no indication that grafting success and age were related. At the stem level, hydraulic conductance scaled with total leaf area so that total conductance per unit leaf area did not vary with crown size. However, leaf specific hydraulic conductance (gravimetric), transpiration, photosynthesis and stomatal conductance declined with increasing total tree leaf area and needle width. We hypothesize that needle width is inversely related to mesophyll conductance. We conclude that canopy and needle size and not scion donor-tree age determined gas exchange in our grafted trees.

[Outcomes of surgical treatment in 100 patients with arteriovenous malformations of the brain]. / Resultados del tratamiento quirúrgico en 100 pacientes con malformaciones arteriovenosas cerebrales.

AIM: To conduct a descriptive analysis of a series of patients with arteriovenous malformations (AVM) that had been treated surgically. PATIENTS AND METHODS: Of a total of 189 adult patients with AVM evaluated consecutively in our hospital, 100 patients who had undergone surgical treatment were selected; a number of demographic, clinical and radiological aspects were then analysed, together with data concerning any associated vascular lesions, the type of surgical treatment, angiographic results and clinical outcomes. RESULTS: The mean age was 34 years (range: 15-71 years). The most common presenting symptom was intracranial haemorrhage, which occurred in 60 cases (60%). The AVM were located in the supratentorial convexity in 79% of cases, 8% were deep and 13% were situated in the cerebellum. The most frequent degree, according to the Spetzler and Martin scale, was grade III. Seventeen patients had other associated lesions and it should be noted that eight patients had aneurysms. Most of the patients (78%) underwent elective surgery and, in two cases, post-embolisation. Surgical treatment (salvage surgery) was performed in 13 patients (13%) when other therapeutic options failed and seven patients were submitted to emergency operations because of brain haemorrhages. The postoperative angiographic study showed complete removal of the AVM in 98% of cases. The clinical outcomes were as follows: 75%, good recovery; 20%, moderate incapacity; and 5%, an important degree of incapacity. CONCLUSION: Surgery is the best therapeutic option for patients with AVM, if they are selected in an appropriate manner.

[Causes of hospital mortality due to brain haemorrhage in patients with arteriovenous malformation]. / Causas de la mortalidad hospitalaria por hemorragia cerebral en pacientes con malformacion arteriovenosa.

AIM: To determine the causes of mortality in cases of brain haemorrhage among patients with arteriovenous malformations (AVM) treated in a tertiary hospital. PATIENTS AND METHODS: The patients with AVM who died over the period 1990-2014 were selected from a prospective register of vascular malformations. Demographic aspects, localisation of the AVM, associated aneurysms and previous treatments were reviewed. Three main causes of death were established: initial bleeding/rebleeding, those related with the treatment of the AVM and other causes not related with AVM. RESULTS: A total of 400 patients were treated for AVM, 216 (54%) with a ruptured AVM, of whom 26 (12.1%) died as a result of a brain haemorrhage. The mean age of the group of patients who died was 48.8 years (range: 8-78 years). Twenty (76.9%) were admitted in coma (Glasgow Coma Scale < 9). In five cases (19.2%), bleeding was due to an associated aneurysm. A very high percentage (38.5%) had the AVM in the posterior fossa. Three patients had previously received non-curative treatments for the AVM in other medical centres. Of the total number, six (23.1%) received endovascular/surgical treatment in our hospital, and we have assumed that, due to the indication or owing to the time in which it was carried out, the cause of death was treatment-related, although two young patients underwent surgery with bilateral mydriasis. One patient died due to an associated glioblastoma, and the others, 19 (76%), due to rebleeding or to the initial brain damage. CONCLUSION: Knowing the causes of mortality can help improve the clinical outcome, above all in cases in which an early treatment could be indicated.

TITLE: Causas de la mortalidad hospitalaria por hemorragia cerebral en pacientes con malformacion arteriovenosa.Objetivo. Conocer las causas de la mortalidad en la hemorragia cerebral de los pacientes con malformaciones arteriovenosas (MAV) tratadas en un hospital terciario. Pacientes y metodos. De un registro prospectivo de malformaciones vasculares se han seleccionado los pacientes que fallecieron con MAV en el periodo 1990-2014. Se han revisado aspectos demograficos, localizacion de la MAV, aneurismas asociados y tratamientos previos. Se han establecido tres causas principales de muerte: sangrado inicial/resangrado, relacionadas con el tratamiento de la MAV y otras causas no relacionadas con la MAV. Resultados. Se trato a 400 pacientes de MAV, 216 (54%) con MAV rotas, de los que fallecieron 26 (12,1%) por hemorragia cerebral. La media de edad del grupo de pacientes fallecidos fue de 48,8 años (rango: 8-78 años). Veinte (76,9%) ingresaron en coma (escala de coma de Glasgow < 9). En cinco casos (19,2%), el sangrado se debio a un aneurisma asociado. Un porcentaje muy elevado (38,5%) tenia la MAV en la fosa posterior. Tres pacientes habian recibido previamente en otros centros tratamientos no curativos de la MAV. Del total, seis (23,1%) recibieron tratamiento endovascular/quirurgico en nuestro hospital, y hemos asumido que, por la indicacion o por el momento en que se realizo, la causa de la muerte se relacionaba con el tratamiento, aunque dos pacientes jovenes se operaron con midriasis bilateral. Un paciente fallecio por un glioblastoma asociado, y el resto, 19 (76%), por el resangrado o el daño cerebral inicial. Conclusion. El conocimiento de las causas de mortalidad puede contribuir a mejorar el resultado clinico, sobre todo en los casos en que podria estar indicado un tratamiento precoz.

Isohydric species are not necessarily more carbon limited than anisohydric species during drought.

Isohydry (i.e., strong regulation of leaf water potential, Ψl) is commonly associated with strict stomatal regulation of transpiration under drought, which in turn is believed to minimize hydraulic risk at the expense of reduced carbon assimilation. Hence, the iso/anisohydric classification has been widely used to assess drought resistance and mortality mechanisms across species, with isohydric species being hypothetically more prone to carbon starvation and anisohydric species more vulnerable to hydraulic failure. These hypotheses and their underlying assumptions, however, have rarely been tested under controlled, experimental conditions. Our objective is to assess the physiological mechanisms underlying drought resistance differences between two co-occurring Mediterranean forest species with contrasting drought responses: Phillyrea latifolia L. (anisohydric and more resistant to drought) and Quercus ilex L. (isohydric and less drought resistant). A total of 100 large saplings (50 per species) were subjected to repeated drought treatments for a period of 3 years, after which Q. ilex showed 18% mortality whereas no mortality was detected in P. latifolia. Relatively isohydric behavior was confirmed for Q. ilex, but higher vulnerability to cavitation in this species implied that estimated embolism levels were similar across species (12-52% in Q. ilex vs ~30% in P. latifolia). We also found similar seasonal patterns of stomatal conductance and assimilation between species. If anything, the anisohydric P. latifolia tended to show lower assimilation rates than Q. ilex under extreme drought. Similar growth rates and carbon reserves dynamics in both species also suggests that P. latifolia was as carbon-constrained as Q. ilex. Increasing carbon reserves under extreme drought stress in both species, concurrent with Q. ilex mortality, suggests that mortality in our study was not triggered by carbon starvation. Our results warn against making direct connections between Ψl regulation, stomatal behavior and the mechanisms of drought-induced mortality in plants.

[Predictive value of the Knosp classification in grading the surgical resection of invasive pituitary macroadenomas. A prospective study of 23 cases]. / Valor predictivo de la clasificación de Knosp en el grado de resección quirúrgica de los macroadenomas invasivos. Estudio prospectivo de una serie de 23 casos.

OBJECTIVE: To evaluate our experience regarding the treatment of pituitary macroadenomas with cavernous sinus invasion in a series of 23 cases of transphenoidal resection. MATERIALS, METHODS AND RESULTS: Twenty two patients, fifteen males and seven females, with ages ranging from 27 to 75 (mean of 48), were operated under protocol by a single surgeon between May of 2002 and December of 2004. Preoperatively all lesions were diagnosed by MRI and staged according to the Knosp classification. All tumors had extension to one or both cavernous sinuses. Four patients were considered to be grade 1, two grade 2, one grade 3 and sixteen grade 4. Twenty three operations were performed on twenty-two patients. Twenty cases were the standard transsphenoidal approach, and three were endoscopic. Postoperatively, the excision was classified as Complete or Total, Subtotal or Partial. Mean follow up was 15 months. The variables considered for analysis include invasion and resection grades. All six patients with graded 1 and 2 lesions and two patients with grade 4 lesions underwent a complete resection. Subtotal (greater than 80%) excision was achieved in one patient with a grade 3 tumor and six patients with grade 4 tumors. The remaining seven patients with grade 4 adenomas had a Partial (less than 80%) excision. We compare de resection grade versus invasion grade with exact Fisher test. And there is not estadistical difference (p=0.12). CONCLUSION: The Knosp classification alone cannot predict the behavior of these tumors. In our experience, despite tumor extension to the cavernous sinus, pituitary macroadenomas can be safely resected with low morbidity and mortality.

[Variability in the surgical indications for posttraumatic intradural lesions]. / Variabilidad en las indicaciones quirúrgicas de las lesiones intradurales postraumáticas.

INTRODUCTION: The surgical treatment of focal intradural lesions is still a matter of considerable debate. This is especially important in the decision to evacuate brain contusions. We present the results of a prospective observational study in which the main goal was to analyze intracenter variability in the indication for surgery in focal posttraumatic intradural lesions in a department of Neurosurgery of a University Hospital with a specialized neurotrauma unit. CLINICAL MATERIAL AND METHODS: Between May 1 and December 31, 2001, 32 patients with a closed traumatic brain injury and an intradural posttraumatic focal lesion were included. The patients studied were a subgroup included in the European multicenter observational study of the management of intradural lesions conducted under the aegis of the European Brain Injury Consortium (EBIC). RESULTS: Intradural lesions > 25 cc were immediately evacuated. Nine out of thirteen patients with lesions < 25 cc also underwent surgery due to intracranial hypertension or neuroworsening. In all patients in whom lesions were surgically evacuated, the postoperative CT-scan showed neuroradiological improvement of the signs of mass effect or midline shift. CONCLUSIONS: In our center, we found no evidence of significant variability in the indications for surgery in intradural lesions of more than 25 cc. However, significant differences were detected among neurosurgeons in the surgical indications for lesions below 25 cc. The small sample analyzed precludes generalization of these conclusions. The definitive results of the EBIC study will provide the neurosurgical community with a better understanding of variability in the management of these lesions.