A randomised controlled feasibility trial of a clinical protocol to manage hypotension during major non-cardiac surgery.

Intra-operative hypotension is a risk factor for postoperative morbidity and mortality. Minimally invasive monitors that derive other haemodynamic parameters, such as stroke volume, may better inform the management of hypotension. As a prelude to a multicentre randomised controlled trial, we conducted a single-centre feasibility trial of a protocol to treat hypotension as informed by minimally invasive haemodynamic monitoring during non-cardiac surgery. We recruited adults aged ≥40 years with cardiovascular risk factors who underwent non-cardiac surgery requiring invasive arterial pressure monitoring. Participants were randomly allocated to usual care, or a clinical protocol informed by an arterial waveform contour analysis monitor. Participants, outcome assessors, clinicians outside operating theatres and analysts were blinded to treatment allocation. Feasibility was evaluated based on: consent rate; recruitment rate; structured feedback from anaesthesia providers; and between-group differences in blood pressure, processes-of-care and outcomes. The consent rate among eligible patients was 33%, with 30 participants randomly allocated to the protocol and 30 to usual care. Anaesthesia providers rated the protocol to be feasible and acceptable. The protocol was associated with reduced fluid balance and hypotension exposure in the peri-operative setting. Postoperative complications included: acute myocardial injury in 18 (30%); acute kidney injury in 17 (28%); and surgical site infection in 7 (12%). The severity of complications was rated as moderate or severe in 25 (42%) participants. In summary, this single-centre study confirmed the feasibility of a multicentre trial to assess the efficacy and safety of a physiologically guided treatment protocol for intra-operative hypotension based on minimally invasive haemodynamic monitors.

Comparative analyses of published cost effectiveness models highlight critical considerations which are useful to inform development of new models.

Background: Comparative analyses of published cost effectiveness models provide useful insights into critical issues to inform the development of new cost effectiveness models in the same disease area.Objective: The purpose of this study was to describe a comparative analysis of cost-effectiveness models and highlight the importance of such work in informing development of new models. This research uses genotypic antiretroviral resistance testing after first line treatment failure for Human Immunodeficiency Virus (HIV) as an example.Method: A literature search was performed, and published cost effectiveness models were selected according to predetermined eligibility criteria. A comprehensive comparative analysis was undertaken for all aspects of the models.Results: Five published models were compared, and several critical issues were identified for consideration when developing a new model. These include the comparator, time horizon and scope of the model. In addition, the composite effect of drug resistance prevalence, antiretroviral therapy efficacy, test performance and the proportion of patients switching to second-line ART potentially have a measurable effect on model results. When considering CD4 count and viral load, dichotomizing patients according to higher cost and lower quality of life (AIDS) versus lower cost and higher quality of life (non-AIDS) status will potentially capture differences between resistance testing and other strategies, which could be confirmed by cross-validation/convergent validation. A quality adjusted life year is an essential outcome which should be explicitly explored in probabilistic sensitivity analysis, where possible.Conclusions: Using an example of GART for HIV, this study demonstrates comparative analysis of previously published cost effectiveness models yields critical information which can be used to inform the structure and specifications of new models.

Predictors of Post-operative Pain and Opioid Consumption in Patients Undergoing Liver Surgery.

BACKGROUND: Post-operative pain management is a critical component of perioperative care. Patients at risk of poorly controlled post-operative pain may benefit from early measures to optimize pain management. We sought to identify risk factors for post-operative pain and opioid consumption in patients undergoing liver resection. METHODS: This is a multi-institutional prospective nested cohort study of patients undergoing open liver resection. Opioid consumption and pain scores were collected following surgery. To estimate the effects of patient factors on opioid consumption (oral morphine equivalents-OME) and on pain scores (NRS-11), we used generalized linear models and multivariable linear regression model, respectively. RESULTS: One hundred and fifty-three patients who underwent open liver resection between 2013 and 2016 were included in the study. The mean patient age was 62.2 years, and 43.3% were female. Younger patients were significantly more likely to use more opioids in the early post-operative period (16.7 OME/10 years, p < 0.001). Patient factors that were significantly associated with increased NRS-11 pain scores also included younger patient age (difference in pain score of 0.3/10 years with cough and 0.2/10 years at rest, p < 0.01 for both) as well as a history of analgesic use (difference in pain score of 0.9 with cough and 0.6 at rest, p < 0.01 and p = 0.07, respectively). CONCLUSION: Younger patients and those with a history of analgesic use are more likely to report higher post-operative pain and require higher doses of opioids. Early identification of these patients, and measures to better manage their pain, may contribute to optimal perioperative care.

Use of prothrombin complex concentrate for management of coagulopathy after cardiac surgery: a propensity score matched comparison to plasma.

BACKGROUND: An important cause of coagulopathy in cardiac surgery is impaired thrombin generation. While plasma is often used to correct this element of the coagulopathy, studies in vitro suggest that prothrombin complex concentrates (PCCs) might be more effective. Comparative data, however, are scant. METHODS: We compared the outcomes of those who received only plasma with those who received PCCs (with or without plasma) for management of coagulopathy in patients who underwent cardiac surgery with cardiopulmonary bypass at a single institution from 2012 to 2016. Propensity score matching was used to obtain between-group balance. Primary outcome was avoidance of perioperative red cell transfusions. Other outcomes were incidence of massive transfusion (more than nine red cell units), refractory bleeding (requiring factor VIIa), and adverse events. RESULTS: Of 6362 patients, 1151 (18.2%) received plasma without any PCCs, and 204 (3.2%) received PCCs, either with (n=125) or without plasma (n=79). Overall, patient risk-profile was higher in the PCCs group. In a well-balanced propensity score match that included 117 patients per group, the odds ratio (OR) for red cell avoidance was 2.4-fold [95% confidence interval (CI) 1.2-4.8] higher in the PCCs group. Massive transfusion (OR 0.58; 95% CI 0.33-1.0) and refractory bleeding (OR 0.49; 95% CI 0.24-1.03) incidences were almost significantly lower in the PCCs group. The adverse event profiles were similar. CONCLUSIONS: Our exploratory study suggests that the use of PCCs as part of a multifaceted coagulation management strategy may have blood-sparing effects. Their incorporation into clinical practice, however, must await determination of their risk-benefit profile via multicentre randomised trials.

Alum Activates the Bovine NLRP3 Inflammasome.

There has been a move away from vaccines composed of whole or inactivated antigens toward subunit-based vaccines, which although safe, provide less immunological protection. As a result, the use of adjuvants to enhance and direct adaptive immune responses has become the focus of much targeted bovine vaccine research. However, the mechanisms by which adjuvants work to enhance immunological protection in many cases remains unclear, although this knowledge is critical to the rational design of effective next generation vaccines. This study aimed to investigate the mechanisms by which alum, a commonly used adjuvant in bovine vaccines, enhances IL-1ß secretion in bovine peripheral blood mononuclear cells (PBMCs). Unlike the case with human PBMCs, alum promoted IL-1ß secretion in a subset of bovine PBMCs without priming with a toll-like receptor agonist. This suggests that PBMCs from some cattle are primed to produce this potent inflammatory cytokine and western blotting confirmed the presence of preexisting pro-IL-1ß in PBMCs from a subset of 8-month-old cattle. To address the mechanism underlying alum-induced IL-1ß secretion, specific inhibitors identified that alum mediates lysosomal disruption which subsequently activates the assembly of an NLRP3, ASC, caspase-1, and potentially caspase-8 containing complex. These components form an inflammasome, which mediates alum-induced IL-1ß secretion in bovine PBMCs. Given the demonstrated role of the NLRP3 inflammasome in regulating adaptive immunity in murine systems, these results will inform further targeted research into the potential of inflammasome activation for rational vaccine design in cattle.

Greater intravenous fluid volumes are associated with prolonged recovery after colorectal surgery: a retrospective cohort study.

BACKGROUND: We carried out a retrospective assessment of whether perioperative fluid volume was associated with length of hospital stay (LOS) after colorectal surgery. METHODS: A single-centre chart review was conducted on colorectal surgeries that took place between January 2008 and December 2013. The primary outcome was LOS, with prolonged LOS defined as greater than median LOS. Secondary outcomes included postoperative pulmonary oedema, acute renal failure, myocardial infarction, and mortality. Univariate analysis, multivariable logistic regression, and quantile regression analyses were conducted to examine the association between perioperative fluid volume and prolonged LOS. RESULTS: Of the 1242 procedures, 57% were elective, 62% oncological, and 31% laparoscopic. The median LOS was 8.2 days (interquartile range 5.2, 14.7). Patients received 3.2 (sd 1.5) litres of fluid in the perioperative period (operating and recovery rooms), predominantly crystalloid. The volume (in litres) of perioperative fluid was independently associated with prolonged LOS (odds ratio 1.23, 95% confidence interval 1.10-1.36, P<0.01). This association persisted across the spectrum of definitions for prolonged LOS (10th-90th percentile). Logistic regression analysis also revealed that prolonged LOS was associated with age >65 yr, Charlson Co-morbidity Index ≥3, use of colloids, emergent surgery, estimated blood loss >200 ml, preoperative anaemia, erythrocyte transfusion, open surgeries, and surgical duration >4 h (C-statistic=0.79, Hosmer-Lemeshow=0.36). CONCLUSIONS: Greater perioperative fluid volume was independently associated with prolonged duration of recovery across a spectrum of surgical risk profiles. Fluid restriction should be considered a part of the care package in enhanced recovery after surgery programmes for colorectal surgery.

Red cell transfusion and the immune system.

Understanding the complex immunological consequences of red cell transfusion is essential if we are to use this valuable resource wisely and safely. The decision to transfuse red cells should be made after serious considerations of the associated risks and benefits. Immunological risks of transfusion include major incompatibility reactions and transfusion-related acute lung injury, while other immunological insults such as transfusion-related immunomodulation are relatively underappreciated. Red cell transfusions should be acknowledged as immunological exposures, with consequences weighed against expected benefits. This article reviews immunological consequences and the emerging evidence that may inform risk-benefit considerations in clinical practice.

Pharmacokinetics of tranexamic acid in patients undergoing cardiac surgery with use of cardiopulmonary bypass.

We conducted a study to assess pharmacokinetics of high-dose tranexamic acid for 24 h after administration of the drug in patients undergoing cardiac surgery with cardiopulmonary bypass. High-dose tranexamic acid involved a bolus of 30 mg.kg(-1) infused over 15 min followed by a 16 mg.kg(-1) .h(-1) infusion until chest closure with a 2 mg.kg(-1) load within the pump prime. Tranexamic acid followed first-order kinetics best described using a two-compartment model, with a total body clearance that approximated the glomerular filtration rate. Mean plasma tranexamic acid concentrations during the intra-operative period and in the first 6 postoperative hours were consistently higher than the suggested threshold to achieve 100% inhibition and 80% inhibition of tissue plasminogen activator. With recent studies implicating high-dose tranexamic acid as a possible aetiology of postoperative seizures following cardiac surgery, the minimum effective yet safe dose of tranexamic acid in high-risk cardiac surgery needs to be refined.

Glasgow supported self-management trial (GSuST) for patients with moderate to severe COPD: randomised controlled trial.

OBJECTIVE: To determine whether supported self management in chronic obstructive pulmonary disease (COPD) can reduce hospital readmissions in the United Kingdom. DESIGN: Randomised controlled trial. SETTING: Community based intervention in the west of Scotland. PARTICIPANTS: Patients admitted to hospital with acute exacerbation of COPD. INTERVENTION: Participants in the intervention group were trained to detect and treat exacerbations promptly, with ongoing support for 12 months. MAIN OUTCOME MEASURES: The primary outcome was hospital readmissions and deaths due to COPD assessed by record linkage of Scottish Morbidity Records; health related quality of life measures were secondary outcomes. RESULTS: 464 patients were randomised, stratified by age, sex, per cent predicted forced expiratory volume in 1 second, recent pulmonary rehabilitation attendance, smoking status, deprivation category of area of residence, and previous COPD admissions. No difference was found in COPD admissions or death (111/232 (48%) v 108/232 (47%); hazard ratio 1.05, 95% confidence interval 0.80 to 1.38). Return of health related quality of life questionnaires was poor (n=265; 57%), so that no useful conclusions could be made from these data. Pre-planned subgroup analysis showed no differential benefit in the primary outcome relating to disease severity or demographic variables. In an exploratory analysis, 42% (75/150) of patients in the intervention group were classified as successful self managers at study exit, from review of appropriateness of use of self management therapy. Predictors of successful self management on stepwise regression were younger age (P=0.012) and living with others (P=0.010). COPD readmissions/deaths were reduced in successful self managers compared with unsuccessful self managers (20/75 (27%) v 51/105 (49%); hazard ratio 0.44, 0.25 to 0.76; P=0.003). CONCLUSION: Supported self management had no effect on time to first readmission or death with COPD. Exploratory subgroup analysis identified a minority of participants who learnt to self manage; this group had a significantly reduced risk of COPD readmission, were younger, and were more likely to be living with others. TRIAL REGISTRATION: Clinical trials NCT 00706303.

Increasing response rates to lifestyle surveys: a pragmatic evidence review.

AIMS: Lifestyle surveys are often a key component of a local Joint Strategic Needs Assessment (JSNA), undertaken to inform public health planning. They are usually administered to a large number of people in order to provide a comprehensive profile of population health. However, declining response rates coupled with the under-representation of certain population groups in lifestyle survey data has led to doubts concerning the reliability of findings. In order to inform the design of their own lifestyle survey, NHS Calderdale commissioned an evidence-based review of the methodological literature relating to the administration of lifestyle surveys, with the specific aim of identifying practical and resource-efficient strategies shown to be effective for maximizing whole-population response rates. METHODS: A pragmatic review of the published literature was undertaken, specifically to explore the most practical and resource-efficient ways to maximize lifestyle survey response rates to the most commonly used methods (postal surveys, face-to-face interviews, telephone interviews and electronic surveys). Electronic databases including MEDLINE, CINAHL, DARE, EMBASE and PsychINFO were searched. Empirical evidence published in the last 10 years was identified and citation tracking performed on all retrieved articles. An internet search for 'grey literature' was also conducted. RESULTS: The postal questionnaire remains an important lifestyle survey tool, but reported response rates have decreased rapidly in recent years. Interviews and telephone surveys are recommended in order to supplement data from postal questionnaires and increase response rates in some population groups, but costs may be prohibitive. Electronic surveys are a cheaper alternative, but the empirical evidence on effectiveness is inconclusive. Careful planning and tailoring of survey design to the characteristics of target populations can increase response rates and representativeness of lifestyle survey data. CONCLUSIONS: The results of this pragmatic review could provide a valuable resource for those involved in the design and administration of lifestyle surveys.

In situ hypothermic liver preservation during radical liver resection with major vascular reconstruction.

BACKGROUND: The in situ hypothermic liver preservation technique may allow a more aggressive approach to tumours of the caval confluence and/or all three hepatic veins, which would otherwise be deemed irresectable. METHODS: All descriptive data regarding patient demographics, operative characteristics, perioperative complications and outcomes of nine patients in whom this technique was used were collected prospectively. RESULTS: Seven patients underwent liver trisegmentectomy and two had primary retrohepatic venal caval resection. Total hepatic vascular occlusion with in situ hypothermic liver preservation was used for venous reconstruction in all patients. The vena cava was reconstructed with prosthetic graft in seven patients. All main hepatic veins were reconstructed in the seven liver resections. In situ hypothermic liver preservation was well tolerated as evidenced by preserved hepatic synthetic function early after operation. One patient died 66 days after surgery. There were two recurrences after a median follow-up of 14 (range 2-33) months; local recurrence was identified in one patient after 4 months and distant metastasis in another after 8 months. CONCLUSION: The in situ hypothermic liver preservation technique appears to be a useful adjunct to radical hepatobiliary tumour excision procedures that require total hepatic vascular exclusion and major vascular reconstruction.

A holistic approach to the management of a neuropathic plantar ulcer.

While pressure relief is a vital component of the treatment of neuropathic plantar foot ulcers, many patients are reluctant to wear offloading devices. Healing is more likely to occur if the patient is happy with its appearance and comfort.

Development of the vestibular apparatus and central vestibular connections in a wallaby (Macropus eugenii).

We have studied the early development of the vestibular apparatus and its central connections in the tammar wallaby (Macropus eugenii) in order to determine whether the vestibular system anatomy is sufficiently mature at birth to assist in climbing to the pouch. Structural development was studied with the aid of hematoxylin and eosin stained sections and immunoreactivity for GAP-43, whereas the development of vestibular system connections was examined by carbocyanine dye tracing. At the time of birth, the otocyst has distinct utricle, saccule and semicircular canals with immature sensory regions receiving innervation by GAP-43 immunoreactive fibers. Vestibular nerve fibers can be traced into the brainstem to the developing vestibular nuclei, which are not yet cytoarchitectonically distinct. The vestibular nuclei do not contribute direct projections to the lower cervical spinal cord at birth; most bulbospinal projections in the newborn appear to be derived bilaterally from the gigantocellular, lateral paragigantocellular reticular and ventral medullary nuclei. A substantial bilateral projection to the vestibular ganglion and apparatus from the region of the gigantocellular and lateral paragigantocellular nuclei was seen at birth, but not in subsequent ages. This is similar to a projection seen in newborn Ameridelphians. By postnatal day (P) 5, the vestibular apparatus had extensive projections to all vestibular nuclei and neurons projecting in the lateral vestibulospinal tract could be identified in the lateral vestibular nucleus. Cytoarchitectonic differentiation of the vestibular nuclei proceeded over the next 3 to 4 weeks with the emergence of discrete parvicellular and magnocellular components of the medial vestibular nucleus by P19. GAP-43 immunoreactivity stayed high in the lateral vestibulospinal tract for several months after birth, suggesting that the development of this tract followed a prolonged timecourse. Our findings indicate that central and peripheral connections of the vestibular ganglion are present at birth, but that there is no direct projection from the vestibular nuclei to the cervical spinal cord until P5. Nevertheless, the possibility remains that an indirect projection between the vestibular nuclei and the medial reticular formation is present at birth and mediates control of the climb.

Vascular targeted photodynamic therapy with palladium-bacteriopheophorbide photosensitizer for recurrent prostate cancer following definitive radiation therapy: assessment of safety and treatment response.

PURPOSE: Tookad is a novel intravascular photosensitizer. When activated by 763 nm light, it destroys tumors by damaging their blood supply. It then clears rapidly from the circulatory system. To our knowledge we report the first application of Tookad vascular targeted photodynamic therapy in humans. We assessed the safety, pharmacokinetics and preliminary treatment response as a salvage procedure after external beam radiation therapy. MATERIALS AND METHODS: Patients received escalating drug doses of 0.1 to 2 mg/kg at a fixed light dose of 100 J/cm or escalated light doses of 230 and 360 J/cm at the 2 mg/kg dose. Four optical fibers were placed transperineally in the prostate, including 2 for light delivery and 2 for light dosimetry. Treatment response was assessed primarily by hypovascular lesion formation on contrast enhanced magnetic resonance imaging and transrectal ultrasound guided biopsies targeting areas of lesion formation and secondarily by serum prostate specific antigen changes. RESULTS: Tookad vascular targeted photodynamic therapy was technically feasible. The plasma drug concentration was negligible by 2 hours after infusion. In the drug escalation arm 3 of 6 patients responded, as seen on magnetic resonance imaging, including 1 at 1 mg/kg and 2 at 2 mg/kg. The light dose escalation demonstrated an increasing volume of effect with 2 of 3 patients in the first light escalation cohort responding and all 6 responding at the highest light dose with lesions encompassing up to 70% of the peripheral zone. There were no serious adverse events, and continence and potency were maintained. CONCLUSIONS: Tookad vascular targeted photodynamic therapy salvage therapy is safe and well tolerated. Lesion formation is strongly drug and light dose dependent. Early histological and magnetic resonance imaging responses highlight the clinical potential of Tookad vascular targeted photodynamic therapy to manage post-external beam radiation therapy recurrence.

Reductions in cardiovascular risk in association with population screening: a 10-year longitudinal study.

BACKGROUND: This study was carried out in order to examine changes in cardiovascular risk associated with a population-based screening programme. METHOD: Cardiovascular disease (CVD) risk factor data from a representative sample of residents aged between 45 and 55 years who attended screening a total of three times over a 10-year period were chosen for analysis (n=4113). Cohorts were defined as either 'high risk' or 'normal risk' at baseline for risk factors including blood pressure, body mass index (BMI), cholesterol, smoking and alcohol intake. Mean changes were observed for both groups over three screening episodes, and results were stratified by gender. RESULTS: For the high-risk cohorts (after controlling for age and regression to the mean effects), there were significant decreases in all risk factors, except BMI. Conversely, the observed changes in the normal risk cohorts indicated significant increases in risk factors over the 10-year period. After adjusting for age, the pattern in the normal risk cohorts fluctuated and there were some decreases in risk, but they were not as large as the decreases in risk for the high-risk cohorts. CONCLUSIONS: Population screening for CVD is an effective strategy for identifying and reducing risk in high-risk individuals. These results have significant implications for the role of screening in preventing and controlling cardiovascular disease.

The effects of a treatment protocol for cardiac surgical patients with excessive blood loss on clinical outcomes.

BACKGROUND AND OBJECTIVES: Excessive blood loss (EBL) is a common complication of cardiac surgery that is associated with adverse events. The objective of this before/after study was to determine whether the implementation of a protocol for management of cardiac surgical patients with EBL was associated with improved clinical outcomes. MATERIALS AND METHODS: In November 2002, a protocol for prompt identification and aggressive management of cardiac surgical patients with EBL was implemented at our institution. The independent relationship between protocol implementation and adverse outcomes was measured by comparing the outcomes of patients who received > or = 4 RBC (red blood cell) units within 1 day of surgery and were operated on before protocol implementation (2000-02) with those operated on after protocol implementation (2003-05), using multivariable logistic regression analysis to control for the effects of confounders. The primary outcome was a composite of adverse events that included death, renal failure, stroke, and sepsis. Bootstrapping was used to confirm the validity of the results. RESULTS: Of the 11,314 patients who underwent surgery during the study period, 1875 (16.6%) received > or = 4 RBC units within 1 day of surgery, with 958 and 917 in the pre- and postprotocol periods, respectively. The composite adverse outcome occurred in 164 (17.1%) patients in the preprotocol period and 115 (12.5%) patients in the postprotocol period (P = 0.005). Protocol implementation was independently associated with reduced odds of the composite adverse outcome (odds ratio 0.67; 95% confidence interval 0.50, 0.91; P = 0.01). This estimate was stable in bootstrap sampling. CONCLUSION: Implementation of a protocol to manage EBL in cardiac surgery was independently associated with improved outcomes.

A multivariable model for predicting the need for blood transfusion in patients undergoing first-time elective coronary bypass graft surgery.

BACKGROUND: The incidence of blood transfusion in coronary artery bypass graft (CABG) surgery remains high. Preoperative identification of those at high risk for requiring blood will allow for the cost-effective use of some blood conservation modalities. Multivariable analysis techniques were used in this study to develop a prediction rule for such a purpose. STUDY DESIGN AND METHODS: Data were prospectively collected for all patients undergoing elective first-time CABG surgery from January 1997 to September 1998 at a tertiary-care teaching hospital (n = 1007). The prediction rule was developed on the first two-thirds of the sample by using logistic regression methods to examine the relationship of patient demographics, comorbidities, and preoperative Hb with perioperative blood transfusion. The remaining one-third of the sample was used to validate the rule. RESULTS: The transfusion rate was 29.4 percent. The prediction rule included preoperative Hb (g/dL, OR 0.928, p<0.0001), weight (kg, OR 0.938, p<0.0001), age (years, OR 1.037, p<0.01), and sex (male/female, OR 0.493, p<0.01); receiver operating characteristic = 0.86. When externally validated, the rule had a sensitivity of 82.1 percent and a specificity of 63.6 percent (at a selected probability cutoff). CONCLUSION: A simple and valid prediction rule is developed for predicting the risk of blood transfusion in patients undergoing first-time elective CABG surgery.

Basal activity of the hypothalamic-pituitary-adrenal axis and cognitive function in anorexia nervosa.

Anorexia nervosa is associated with abnormalities in neuroendocrine function including sustained hypercortisolism, which has been shown elsewhere to be associated with impairment of function in learning, memory and attention. Cognitive impairment has also been observed in anorexia nervosa. These effects may be mediated in part through cortisol effects on the hippocampus, which is dense with glucocorticoid receptors. We investigated the association between cortisol levels and cognitive function in anorexia nervosa by measuring both 24-hour urinary cortisol counts and performance on tasks of learning, memory and attention in patients suffering from the disorder. Cortisol secretion was shown to be significantly higher in the patient group than in a matched control group and patients were also shown to be impaired in memory and attention. However, no correlations were found between the cognitive deficits and cortisol measures. It is suggested that more sensitive profiling of cortisol levels throughout the circadian cycle may be useful in future studies of cognitive function in anorexia nervosa.

Alpha-tocopherol inhibits oxidative stress induced by cholestanetriol and 25-hydroxycholesterol in porcine ovarian granulosa cells.

The cytotoxicity of oxysterols including 7-ketocholesterol, alpha-epoxide, cholestanetriol and 25-hydroxycholesterol and the possible protecting effect of alpha-tocopherol on cholestanetriol and 25-hydroxycholesterol-induced cytotoxicity were investigated in primary cultures of porcine ovarian granulosa cells. Cell viability as determined by % trypan blue staining and mitochondrial function as determined using 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) reduction were decreased significantly after 24 h exposure to 2.5 microM alpha-epoxide, cholestanetriol and 25-hydroxycholesterol. 7-Ketocholesterol (2.5 microM) did not affect cell viability or mitochondrial function under the same culture conditions. The specific activities of catalase and superoxide dismutase, two antioxidant defense enzymes were increased significantly (p < 0.01) following 24 h exposure to 2.5 microM concentrations of cholestanetriol while only superoxide dismutase was increased in 25-hydroxycholesterol-treated cells (p < 0.001). Specific activity of glutathione peroxidase was unchanged relative to control cells. Levels of thiobarbituric acid reactive substances remained unchanged after exposure to 7-ketocholesterol, alpha-epoxide, cholestanetriol, 25-hydroxycholesterol and cholesterol. Administration of 1 microM alpha-tocopherol to the culture medium significantly improved cell viability and restored both superoxide dismutase and catalase activities to control levels in cholestanetriol -treated cells and only superoxide dismutase in 25-hydroxycholesterol-treated cells. These studies suggest that the cytotoxic nature of physiologically relevant concentrations of cholestanetriol and 25-hydroxycholesterol in granulosa cells is in part due to oxidative stress, but it may be reduced in the presence of alpha-tocopherol.