Anaesthesia praCtice for Caesarean dElivery Snapshot Study (ACCESS): Protocol and baseline characteristics of registered centres.

BACKGROUND: Specific guidelines to manage caesarean delivery anaesthesia are lacking. A European multicentre study, ACCESS investigates caesarean delivery anaesthesia management in European centres. In order to identify ACCESS participating centres, a registration survey was created. OBJECTIVE: The aim of the current report is to describe the characteristics of ACCESS study participating centres, the rationale for the ACCESS study and the study methodology. DESIGN AND SETTING: The ACCESS study is a European multicentre cross-sectional study to describe anaesthesia management for caesarean delivery (CD) using a snapshot (2-week) design. The ACCESS registration survey gathered: contact details for National Coordinators (NC); Lead Investigators (LI) per centre; centre annual CD volume; expected no. of CD during 2-week snapshot window; centre practice information; data collection language. The ACCESS registration survey was launched July 2022 (Google Forms, Google Inc., Mountain View, CA, USA) and distributed through personal connections, national and international societies, social media networks, during Euroanaesthesia 2023, through the European Society of Anaesthesiology and Intensive Care newsletter. RESULTS: The ACCESS registration survey identified Lead Investigators for 418 centres, in 32 countries, representing an anticipated number of 15,073 CD cases over the planned 12-month study period. A median (range) of 20 (2 to 400) CD cases are anticipated per centre during the 2-week snapshot window. Most 366/418 (87.6%) centres are small, ≤2000 annual CD cases, 42 are medium 2000-5000 cases and 10 are large, ≥5000 annual CD cases. Registered centres reported in 134 (32.0%) centres that anaesthesia for caesarean delivery is performed mostly by a specialist obstetric anaesthesiologist. CONCLUSION: The ACCESS registration survey revealed variability in volume and CD practice as well as training-levels and staffing among European countries. The ACCESS study (https://www.access-study.org/) aims to generate practice data to guide CD anaesthetic management strategies.

Breathing variability during propofol/remifentanil procedural sedation with a single additional dose of midazolam or s-ketamine: a prospective observational study.

PURPOSE: Regulation of spontaneous breathing is highly complex and may be influenced by drugs administered during the perioperative period. Because of their different pharmacological properties we hypothesized that midazolam and s-ketamine exert different effects on the variability of minute ventilation (MV), tidal volume (TV) and respiratory rate (RR). METHODS: Patients undergoing procedural sedation (PSA) with propofol and remifentanil received a single dose of midazolam (1-3 mg, n = 10) or s-ketamine (10-25 mg, n = 10). We used non-invasive impedance-based respiratory volume monitoring to record RR as well as changes in TV and MV. Variability of these three parameters was calculated as coefficients of variation. RESULTS: TV and MV decreased during PSA to a comparable extent in both groups, whereas there was no significant change in RR. In line with our hypothesis we observed marked differences in breathing variability. The variability of MV (- 47.5% ± 24.8%, p = 0.011), TV (- 42.1% ± 30.2%, p = 0.003), and RR (- 28.5% ± 29.3%, p = 0.011) was significantly reduced in patients receiving midazolam. In contrast, variability remained unchanged in patients receiving s-ketamine (MV + 16% ± 45.2%, p = 0.182; TV +12% ± 47.7%, p = 0.390; RR +39% ± 65.2%, p = 0.129). After termination of PSA breathing variables returned to baseline values. CONCLUSIONS: While midazolam reduces respiratory variability in spontaneously breathing patients undergoing procedural sedation, s-ketamine preserves variability suggesting different effects on the regulation of spontaneous breathing.

Variations in respiratory rate do not reflect changes in tidal volume or minute ventilation after major abdominal surgery.

Monitoring of postoperative pulmonary function usually includes respiratory rate and oxygen saturation measurements. We hypothesized that changes in postoperative respiratory rate do not correlate with changes in tidal volume or minute ventilation. In addition, we hypothesized that variability of minute ventilation and tidal volume is larger than variability of respiratory rate. Respiratory rate and changes in tidal volume and in minute ventilation were continuously measured in 27 patients during 24 h following elective abdominal surgery, using an impedance-based non-invasive respiratory volume monitor (ExSpiron, Respiratory Motion, Waltham, MA, US). Coefficients of variation were used as a measure for variability of respiratory rate, tidal volume and minute ventilation. Data of 38,149 measurements were analyzed. We found no correlation between respiratory rate and tidal volume or minute ventilation (r2 = 0.02 and 0.01). Mean respiratory rate increased within the first 24 h after abdominal surgery from 13.9 ± 2.5 to 16.2 ± 2.4 breaths/min (p = 0.008), while tidal volume and minute ventilation remained unchanged (p = 0.90 and p = 0.18). Of interest, variability of respiratory rate (0.21 ± 0.06) was significantly smaller than variability of tidal volume (0.37 ± 0.12, p < 0.001) and minute ventilation (0.41 ± 0.12, p < 0.001). Changes in postoperative respiratory rate do not allow conclusions about changes in tidal volume or minute ventilation. We suggest that postoperative alveolar hypoventilation may not be recognized by monitoring respiratory rate alone. Variability of respiratory rate is smaller than variability in tidal volume and minute ventilation, suggesting that adaptations of alveolar ventilation to metabolic needs may be predominately achieved by variations in tidal volume.

Nocturnal Gamma-Hydroxybutyrate Reduces Cortisol-Awakening Response and Morning Kynurenine Pathway Metabolites in Healthy Volunteers.

BACKGROUND: Gamma-hydroxybutyrate (GHB; or sodium oxybate) is an endogenous GHB-/gamma-aminobutyric acid B receptor agonist. It is approved for application in narcolepsy and has been proposed for the potential treatment of Alzheimer's disease, Parkinson's disease, fibromyalgia, and depression, all of which involve neuro-immunological processes. Tryptophan catabolites (TRYCATs), the cortisol-awakening response (CAR), and brain-derived neurotrophic factor (BDNF) have been suggested as peripheral biomarkers of neuropsychiatric disorders. GHB has been shown to induce a delayed reduction of T helper and natural killer cell counts and alter basal cortisol levels, but GHB's effects on TRYCATs, CAR, and BDNF are unknown. METHODS: Therefore, TRYCAT and BDNF serum levels, as well as CAR and the affective state (Positive and Negative Affect Schedule [PANAS]) were measured in the morning after a single nocturnal dose of GHB (50 mg/kg body weight) in 20 healthy male volunteers in a placebo-controlled, balanced, randomized, double-blind, cross-over design. RESULTS: In the morning after nocturnal GHB administration, the TRYCATs indolelactic acid, kynurenine, kynurenic acid, 3-hydroxykynurenine, and quinolinic acid; the 3-hydroxykynurenine to kynurenic acid ratio; and the CAR were significantly reduced (P < 0.05-0.001, Benjamini-Hochberg corrected). The quinolinic acid to kynurenic acid ratio was reduced by trend. Serotonin, tryptophan, and BDNF levels, as well as PANAS scores in the morning, remained unchanged after a nocturnal GHB challenge. CONCLUSIONS: GHB has post-acute effects on peripheral biomarkers of neuropsychiatric disorders, which might be a model to explain some of its therapeutic effects in disorders involving neuro-immunological pathologies. This study was registered at ClinicalTrials.gov as NCT02342366.

Deber ético del radiólogo: confidencialidad y secreto médico, respeto a la intimidad y dignidad del paciente / Radiologists' duties: confidentiality and professional secrecy, respect for patients' dignity and intimacy

La práctica médica debe estar siempre enmarcada en un ejercicio profesional moralmente aceptable, que procure la promoción y respeto de los principios éticos fundamentales de la medicina, manteniendo el beneficio del paciente como objetivo principal. Al igual que otras especialidades, en el ejercicio de la radiología, se debe cuidar el marco ético profesional que obliga a velar por el respeto de la dignidad e intimidad de las personas y todo lo relacionado con la confidencialidad del acto médico. En el ejercicio de la radiología, al igual en que otros actos médicos, se tiene acceso a información sensible y privada de los pacientes, lo que obliga a hacer un correcto uso de ella, resguardando las normas de privacidad y secreto profesional. Se debe enseñar y sensibilizar a los alumnos y al personal que asiste en el cuidado de los pacientes, para asegurar un comportamiento acorde a las normas éticas que rigen la práctica radiológica.

An ethical and professional medical behavior, which promotes and respects the ethical principles of medicine, is a goal that should always be pursued in medical practice. In radiology, as in other medical specialties, this includes respect for patients' dignity, intimacy and confidentiality. The possibility of accessing patients' private information compels radiologists to make a correct usage of this information, in order to respect professional secrecy and privacy codes that rule medical practice. Radiologists must teach and raise awareness among their students and co-workers in health care institutions of the importance of ethical behavior in their daily practice.

Comparison of Diagnostic Accuracy and Impact of Magnetic Resonance Imaging and Colonoscopy for the Management of Crohn's Disease.

AIMS: The objective of the current study was to compare two patient assessment strategies using colonoscopy and MRI alternatively as first- and second-line examinations. METHODS: Clinical data, endoscopy and magnetic resonance imaging (MRI) examinations of 100 patients diagnosed with ileocolonic Crohn's disease (CD) performed within 1 week were blindly reviewed by 4 clinical investigators. Two investigators evaluated MRI followed by colonoscopy for 50 cases and the same examinations in reverse order for another 50 cases; the other 2 investigators evaluated the same cases switching the order of examinations. The assessments included the likelihood of the presence of inflammation, stenosis, fistula and abscess, and therapeutic recommendations. RESULTS: Information from the first examination was considered sufficient for management in 80% of cases for MRI and only 34% of cases for colonoscopy (p < 0.001). Adding MRI to the information from colonoscopy changed the clinicians' confidence grade in a higher proportion of patients than adding colonoscopy to information from MRI for the diagnosis of disease activity (10 vs 4%, p = 0.03), stenosis (25 vs 9%, p < 0.001), fistula (31 vs 0%, p < 0.001) and internal abscess (27 vs 0%, p < 0.001). Indications for anti-tumour necrosis factor (TNF) therapy (51 vs 37%, F = 0.006), and surgery (12 vs 5%, F = 0.019) were more frequent after MRI than after colonoscopy as first examination. As a second examination, MRI led to change in therapy in a higher proportion of patients than colonoscopy (28 vs 8%, p < 0.001). CONCLUSIONS: In CD, information provided by MRI has a higher impact on patient management than colonoscopy and may be considered as a first-line examination for CD assessment.

Central V1b receptor antagonism in lactating rats: impairment of maternal care but not of maternal aggression.

Maternal behaviour in rodents is mediated by the central oxytocin and vasopressin systems, amongst others. The role of vasopressin, acting via the V1a receptor (V1aR), on maternal care and maternal aggression has recently been described. However, a potential involvement of the V1b receptor (V1bR) in maternal behaviour has only been demonstrated in knockout mice. The present study aimed to examine the effects of central pharmacological manipulation of the V1bR on maternal behaviour in lactating Wistar rats. On pregnancy day 18, female rats were implanted with a guide cannula targeting the lateral ventricle. After parturition, dams received an acute central infusion of a specific V1bR agonist (d[Leu4,Lys8]VP) or V1bR antagonist (SSR149415) once daily, followed by observations of maternal care [lactation day (LD) 1], maternal motivation in the pup retrieval test (LD 2), anxiety-related behaviour on the elevated plus-maze (LD 3) and maternal aggression in the maternal defence test followed by maternal care monitoring (LD 4). Our data demonstrate that, under nonstress conditions, the V1bR antagonist decreased the occurrence of both nursing and mother-pup interaction, whereas the V1bR agonist did not affect either parameter. Under stress conditions (i.e. after the maternal defence test), mother-pup interaction was decreased by infusion of the V1bR antagonist. During the maternal defence test, neither treatment affected aggressive or non-aggressive behaviour. Finally, neither treatment altered maternal motivation or anxiety. In conclusion, central V1bR antagonism modulates aspects of maternal care but not of maternal aggression or maternal motivation in lactating rats. These findings further extend our knowledge on the vasopressin system as a vital mediator of maternal behaviour.

Increased long-term remission after adequate medical cortisol suppression therapy as presurgical treatment in Cushing's disease.

OBJECTIVE: In the last decade, pre-operative medical cortisol suppression therapy has frequently been used in Cushing's disease to normalize cortisol concentrations pre-operatively. Our aim was to assess the efficacy of presurgical medical cortisol suppression therapy in Cushing's disease. DESIGN AND METHODS: We retrospectively assessed the medical files of all patients with Cushing's disease that received presurgical cortisol suppression therapy with ketoconazole or metyrapone and underwent subsequent transsphenoidal surgery between 1990 and 2010 at our centre. We retrieved the pretreatment regimen, adequacy of pretreatment, early postoperative serum cortisol levels, adverse effects and long-term remission status. RESULTS: Nineteen of 33 patients (58%) obtained long-term remission after pituitary surgery without additional postoperative therapy. Thirteen of 16 patients with adequate presurgical cortisol suppression therapy had postoperative cortisol concentrations <50 nmol/l. The 16 patients with adequate presurgical cortisol suppression had a higher long-term remission rate after primary surgery compared with the 13 patients with borderline or inadequate pretreatment (81% vs 38%; P < 0·05). CONCLUSIONS: Adequate presurgical cortisol suppression treatment with ketoconazole or metyrapone in Cushing's disease seems to be associated with suppressed postoperative cortisol concentrations and an increased long-term remission rate.

SU-E-T-271: Irradiating a Single Hippocampus in a Small Rodent Using VMAT- RapidArc SRS: Preliminary Data.

PURPOSE: To develop and optimize the procedures for the precise irradiation of the hippocampal region in a rodent with minimum radiation dose to the remainder of the brain. For this purpose, VMAT-RapidArc SRS was used to irradiate one hippocampus of athymic nude (ATN) rats. Prescribed dose was verified through TLD measurements and spared brain region(s) were confirmed through immunohistochemical analysis postmortem. METHODS: Seven ATN rats, 10-12 weeks old underwent human-like radiation treatment planning followed by SRS. MRI and CT axial images of 0.8 mm thickness of the rat's skull were acquired and transferred to ECLIPSE treatment planning software where brain, right and left hippocampi were contoured. A VMAT-RapidArc plan consisting of two 3600 axial arcs and two 1200 vertex arcs irradiated the left hippocampus only to a dose of 10 Gy. Treatment was delivered using a 6 MV photon beam from a Trilogy Linac equipped with OBI. TLD measurements were performed prior to treatment using a custom made phantom that simulated the rat's brain and body. Orthogonal x-ray images taken with the OBI and co-registered to DRR images were used to adjust the rat's treatment position. One month post- irradiation, rats were sacrificed and brain dissection was performed to verify the radiation effects in the targeted and non-targeted regions. RESULTS: Percent differences between calculated and measured dose were ∼12% which was expected due to the small field sizes (<2cm) used. Immunohistochemistry analysis revealed a significant reduction in cell population in the ipsilateral hippocampus while cell populations comparable to those in a non-irradiated subject were observed in the contralateral hippocampal region. CONCLUSIONS: Present results demonstrate that precise irradiation of small volumes within a rat's brain can be achieved with human-like image-guided VMAT-RapidArc treatment. Postmortem analysis of the rat brain provides evidence of high-precision targeted radiation damage and dose sparing.

Efficacy of infliximab rescue therapy in patients with chronic refractory pouchitis: a multicenter study.

BACKGROUND: Despite medical therapy, 30% of patients with ulcerative colitis (UC) need to undergo surgery. Around 50% of patients with proctocolectomy with ileal pouch-anal anastomosis (IPAA) develop complications of the pouch. Clinical evidence for the use of infliximab (IFX) in refractory pouchitis is limited. The aim of this study was to report efficacy of IFX in these patients. METHODS: A retrospective, multicenter study was designed. Patients older than 18 years with chronic refractory pouchitis treated with IFX (5 mg/kg) were included. Short-term IFX efficacy was evaluated at week 8 and mid-term efficacy at weeks 26 and 52. Complete response was defined as cessation of diarrhea and urgency and partial response as marked clinical improvement but persisting symptoms. The modified Pouchitis Disease Activity Index (mPDAI) without endoscopy was calculated when available. RESULTS: Thirty-three consecutive UC patients with chronic refractory pouchitis were included (18 male, mean age 45 years, range 21-67). At week 8, 21% patients achieved complete response and 63% showed partial clinical response. At weeks 26 and 52, 33% and 27% achieved complete response and 33% and 18% showed partial clinical response, respectively. Thirteen patients (39%) withdrew treatment (four for lack of efficacy, four for loss of response and five for adverse events). None of the potential factors analyzed had an influence on response to IFX. CONCLUSIONS: IFX was effective in the short- and mid-term in patients with chronic refractory pouchitis. However, medication had to be discontinued in a high number of patients.

Changes in the intensity of maternal aggression and central oxytocin and vasopressin V1a receptors across the peripartum period in the rat.

Maternal aggressive behaviour, which protects the offspring from harm, is one component of maternal behaviour. Not only maternal aggression, but also maternal care and social behaviour in general, is regulated by the brain oxytocin (OXT) and vasopressin (AVP) systems. In the present study, we quantified the intensity of maternal aggression using the maternal defence test at key time points throughout pregnancy, parturition and lactation. Furthermore, we quantified changes in central OXT and arginine AVP V1a receptor (V1a-R) binding in brain regions known to be important in regulating maternal aggression, aiming to investigate whether central changes coincide with the intensity of this behaviour. The intensity of aggression was found to dramatically change over the peripartum period, with its first appearance on the day before parturition. Aggression intensity fell immediately after parturition, although it increased during days 4-7 of lactation, before almost disappearing at weaning. OXT receptor (OTR) and V1a-R binding also showed changes through the peripartum period. OTR binding was highest at parturition within the bed nucleus of the stria terminalis and medial preoptic area and on days 4-7 of lactation in the lateral septum (LS) compared to any other time point during the peripartum period. OTR binding positively correlated with the peak of maternal aggression, suggesting that OXT may act in the LS to facilitate the expression of aggressive behaviour. At parturition, V1a-R binding was at its highest levels in the paraventricular nucleus and central amygdala (CeA) and, in the LS, V1a-R binding positively correlated with aggressive behaviour. V1a-R mRNA expression was also increased within the CeA at parturition. Taken together, the observed fluctuations in OTR and V1a-R binding in the neural circuitry important for regulating maternal behaviour may ensure that maternal aggression is expressed at the correct time during the peripartum period.

Review article: stem cell therapies for inflammatory bowel disease - efficacy and safety.

BACKGROUND: Drugs available for the treatment of inflammatory bowel disease fail to induce and maintain remission in a significant number of patients. AIM: To assess the value of stem cell therapies for treatment of inflammatory bowel disease based on published studies. METHODS: Publications were identified through a MEDLINE search using the Medical Subject Heading terms: inflammatory bowel diseases, or Crohn's disease, or ulcerative colitis, and stem cell, or stromal cell or transplant. RESULTS: Haematopoietic stem cell therapy as a primary treatment for inflammatory bowel disease was originally supported by animal experiments, and by remissions in patients undergoing transplant for haematological disorders. Later, transplantation specifically performed for patients with refractory Crohn's disease showed long-lasting clinical remission and healing of inflammatory intestinal lesions. Use of autologous nonmyeloablative regimens and concentration of the procedures in centres with large experience are key in reducing treatment-related mortality. Initial trials of mesenchymal stem cell therapy with local injection in Crohn's perianal fistulas had positive results. CONCLUSIONS: Autologous haematopoietic stem cell transplant changes the natural course of Crohn's disease, and may be a therapeutic option in patients with refractory disease if surgery is not feasible due to disease location or extension.

Maternal behaviour is associated with vasopressin release in the medial preoptic area and bed nucleus of the stria terminalis in the rat.

The neuropeptide arginine vasopressin was recently shown to be an important regulator of female social behaviour, including maternal care and aggression. A key brain site for vasopressin- as well as oxytocin-mediated maternal care is the medial preoptic area (MPOA). Together with the adjacent bed nucleus of the stria terminalis (BNST), these brain regions are considered to form a 'super-region' for maternal behaviour. In the present study, we investigated the vasopressin and oxytocin systems within the MPOA and the BNST during maternal care in lactating rats in more detail. Binding to V1a and oxytocin receptors in the BNST and to oxytocin receptors in the MPOA was increased in lactation. Furthermore, microdialysis revealed that vasopressin release significantly increased (MPOA) or tended to increase (BNST) during different phases of maternal care (i.e. with or without suckling stimulus). In support, manipulations of V1a receptors in the MPOA are known to alter maternal care. We now show that local injection of a selective V1a receptor antagonist bilaterally into the BNST did not affect maternal care, but reduced maternal aggression and tended to lower anxiety-related behaviour. The release of oxytocin did not change in any of the brain regions during maternal care. The results obtained indicate that locally-released vasopressin within the MPOA and the BNST is important for the maintenance of complex maternal behaviours, including maternal care and aggression, respectively.

Sinovitis villonodular pigmentada focal: reporte de un caso / Focal pigmented villonodular synovitis: a case report

Pigmented villonodular synovitis represents a benign synovial proliferation associated to hemosiderin deposits, which originates in bone joints, bursae or tendinous sheaths. The knee articulation is the most commonly involved joint (80 percent of the cases), followed by the hip joint. Normally, this pathology has a diffuse presentation, and a small percentage shows a localized form. PVNS displays very specific imaging features, which allows a good diagnostic approach when aided by different radiological techniques, particularly magnetic resonance imaging (MRI). In this report we describe an infrequent case of focal PVNS localized in the hip, which was treated at "Clínica Alemana", Santiago, Chile.

La sinovitis villonodular pigmentada (SVNP) es una proliferación sinovial benigna asociada a depósitos de hemosiderina, que se origina en articulaciones, bursas o vainas tendíneas. La articulación más comprometida es la rodilla (80 por ciento de los casos), seguida por la cadera. Normalmente, esta patología es de presentación difusa y en un menor porcentaje se da en forma focal. La SVNP posee características imaginológicas muy particulares, lo que permite una buena aproximación diagnóstica de la mano de los diferentes métodos radiológicos, en particular la resonancia magnética. En este reporte se describe un caso poco frecuente de SVNP focal en la cadera, que se presentó en la Clínica Alemana de Santiago.

Magnetic resonance for assessment of disease activity and severity in ileocolonic Crohn's disease.

OBJECTIVE: Assessment of disease extension and activity is crucial to guide treatment in Crohn's disease. The objective of the current cross-sectional study was to determine the accuracy of MR for this assessment. DESIGN: 50 patients with clinically active (n = 35) or inactive (n = 15) Crohn's disease underwent ileocolonoscopy (reference standard) and MR. T2-weighted and precontrast and postcontrast-enhanced T1-weighted sequences were acquired. Endoscopic activity was evaluated by CDEIS (Crohn's Disease Endoscopic Index of Severity); in addition endoscopic lesions were classified as absent, mild (inflammation without ulcers) or severe (presence of ulceration). RESULTS: The comparison of intestinal segments with absent, mild and severe inflammation demonstrated a progressive and significant (p<0.001) increase in the following MR parameters: wall thickness, postcontrast wall signal intensity, relative contrast enhancement, presence of oedema, ulcers, pseudopolyps and lymph node enlargement. Independent predictors for CDEIS in a segment were wall thickness (p = 0.007), relative contrast enhancement (p = 0.01), presence of oedema (p = 0.02) and presence of ulcers at MR (p = 0.003). There was a significant correlation (r = 0.82, p<0.001) between the CDEIS of the segment and the MR index calculated according to the logistic regression analysis coefficients. The MR index had a high accuracy for the detection of disease activity (area under the receiver operating characteristic (ROC) curve 0.891, sensitivity 0.81, specificity 0.89) and for the detection of ulcerative lesions (area under the ROC curve 0.978, sensitivity 0.95, specificity 0.91) in the colon and terminal ileum. CONCLUSION: The accuracy of MR for detecting disease activity and assessing severity brings about the possibility of using MR as an alternative to endoscopy in the evaluation of ileocolonic Crohn's disease.

Prenatal stress reduces postnatal neurogenesis in rats selectively bred for high, but not low, anxiety: possible key role of placental 11beta-hydroxysteroid dehydrogenase type 2.

Prenatal stress (PS) produces persistent abnormalities in anxiety-related behaviors, stress responsivity, susceptibility to psychopathology and hippocampal changes in adult offspring. The hippocampus shows a remarkable degree of structural plasticity, notably in response to stress and glucocorticoids. We hypothesized that PS would differentially affect hippocampal neurogenesis in rats selectively bred for genetic differences in anxiety-related behaviors and stress responsivity. Pregnant dams of high anxiety-related behavior (HAB) and low anxiety-related behavior (LAB) strains were stressed between days 5 and 20 of pregnancy. The survival of newly generated hippocampal cells was found to be significantly lower in 43-day-old HAB than in LAB male offspring of unstressed pregnancies. PS further reduced newly generated cell numbers only in HAB rats, and this was paralleled by a reduction in doublecortin-positive cell numbers, indicative of reduced neurogenesis. As maternal plasma corticosterone levels during PS were similar in both strains, we examined placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), which catalyses rapid inactivation of maternal corticosterone to inert 11-dehydrocorticosterone and thus serves as a physiological 'barrier' to maternal glucocorticoids. PS significantly increased placental 11beta-HSD2 activity in LAB, but not HAB, rats. We conclude that PS differentially affects the number of surviving newly generated cells and neurogenesis in HAB and LAB rats. The high sensitivity of hippocampal neurogenesis to PS in HAB rats is paralleled by a failure to increase placental 11beta-HSD2 activity after stress rather than by different maternal corticosterone responses. Hence, stress-induced placental 11beta-HSD2 expression may be critical in protecting the fetal brain from maternal stress-induced effects on adult neurogenesis.

Social stress induces hypothalamo-pituitary-adrenal axis responses in lactating rats bred for high trait anxiety.

Hypothalamo-pituitary-adrenal axis responses to various stressors are typically attenuated during lactation, including in rats selectively bred for high or low anxiety. As high-anxiety dams are more aggressive towards intruders than low-anxiety dams during maternal defence, we investigated their hypothalamo-pituitary-adrenal axis responses to this social stress. Maternal defence induced elevated stress responses in high-anxiety dams only; nerve-growth-factor-induced gene B mRNA expression in the parvocellular paraventricular nucleus and adrenocorticotropin hormone secretory responses were substantially enhanced after maternal defence. In contrast, secretory responses to a non-social stress (elevated platform) were not different between high- and low-anxiety dams. Thus, responsiveness of the stress axis in lactation is dependent upon the innate level of anxiety of the dam and, as a consequence, her reactiveness to social threat.