Nutrition delivery across hospitalisation in critically ill patients with COVID-19: An observational study of the Australian experience

BACKGROUND

Data on nutrition delivery over the whole hospital admission in critically ill patients with COVID-19 are scarce, particularly in the Australian setting.

OBJECTIVES

The objective of this study was to describe nutrition delivery in critically ill patients admitted to Australian intensive care units (ICUs) with coronavirus disease 2019 (COVID-19), with a focus on post-ICU nutrition practices.

METHODS

A multicentre observational study conducted at nine sites included adult patients with a positive COVID-19 diagnosis admitted to the ICU for >24 h and discharged to an acute ward over a 12-month recruitment period from 1 March 2020. Data were extracted on baseline characteristics and clinical outcomes. Nutrition practice data from the ICU and weekly in the post-ICU ward (up to week four) included route of feeding, presence of nutrition-impacting symptoms, and nutrition support received.

RESULTS

A total of 103 patients were included (71% male, age: 58 ± 14 years, body mass index: 30±7 kg/m2), of whom 41.7% (n = 43) received mechanical ventilation within 14 days of ICU admission. While oral nutrition was received by more patients at any time point in the ICU (n = 93, 91.2% of patients) than enteral nutrition (EN) (n = 43, 42.2%) or parenteral nutrition (PN) (n = 2, 2.0%), EN was delivered for a greater duration of time (69.6% feeding days) than oral and PN (29.7% and 0.7%, respectively). More patients received oral intake than the other modes in the post-ICU ward (n = 95, 95.0%), and 40.0% (n = 38/95) of patients were receiving oral nutrition supplements. In the week after ICU discharge, 51.0% of patients (n = 51) had at least one nutrition-impacting symptom, most commonly a reduced appetite (n = 25; 24.5%) or dysphagia (n = 16; 15.7%).

CONCLUSION

Critically ill patients during the COVID-19 pandemic in Australia were more likely to receive oral nutrition than artificial nutrition support at any time point both in the ICU and in the post-ICU ward, whereas EN was provided for a greater duration when it was prescribed. Nutrition-impacting symptoms were common.

Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI) Scores over Time After Anterior Cruciate Ligament Reconstruction: A Systematic Review with Meta-analysis

BACKGROUND

Psychological readiness is an important consideration for athletes and clinicians when making return to sport decisions following anterior cruciate ligament reconstruction (ACLR). To improve our understanding of the extent of deficits in psychological readiness, a systematic review is necessary.

OBJECTIVE

To investigate psychological readiness (measured via the Anterior Cruciate Ligament-Return to Sport after Injury scale (ACL-RSI)) over time after ACL tear and understand if time between injury and surgery, age, and sex are associated with ACL-RSI scores.

METHODS

Seven databases were searched from the earliest date available to March 22, 2022. Articles reporting ACL-RSI scores after ACL tear were included. Risk of bias was assessed using the ROBINS-I, RoB-2, and RoBANS tools based on the study design. Evidence certainty was assessed for each analysis. Random-effects meta-analyses pooled ACL-RSI scores, stratified by time post-injury and based on treatment approach (i.e., early ACLR, delayed ACLR, and unclear approach).

RESULTS

A total of 83 studies were included in this review (78% high risk of bias). Evidence certainty was 'weak' or 'limited' for all analyses. Overall, ACL-RSI scores were higher at 3 to 6 months post-ACLR (mean = 61.5 [95% confidence interval (CI) 58.6, 64.4], I2 = 94%) compared to pre-ACLR (mean = 44.4 [95% CI 38.2, 50.7], I2 = 98%), remained relatively stable, until they reached the highest point 2 to 5 years after ACLR (mean = 70.7 [95% CI 63.0, 78.5], I2 = 98%). Meta-regression suggests shorter time from injury to surgery, male sex, and older age were associated with higher ACL-RSI scores only 3 to 6 months post-ACLR (heterogeneity explained R2 = 47.6%), and this reduced 1-2 years after ACLR (heterogeneity explained R2 = 27.0%).

CONCLUSION

Psychological readiness to return to sport appears to improve early after ACL injury, with little subsequent improvement until ≥ 2-years after ACLR. Longer time from injury to surgery, female sex and older age might be negatively related to ACL-RSI scores 12-24 months after ACLR. Due to the weak evidence quality rating and the considerable importance of psychological readiness for long-term outcomes after ACL injury, there is an urgent need for well-designed studies that maximize internal validity and identify additional prognostic factors for psychological readiness at times critical for return to sport decisions.

REGISTRATION

Open Science Framework (OSF), https://osf.io/2tezs/ .

Nutrition care processes across hospitalisation in critically ill patients with COVID-19 in Australia: A multicentre prospective observational study

BACKGROUND

The COVID-19 pandemic highlighted major challenges with usual nutrition care processes, leading to reports of malnutrition and nutrition-related issues in these patients.

OBJECTIVE

The objective of this study was to describe nutrition-related service delivery practices across hospitalisation in critically ill patients with COVID-19 admitted to Australian intensive care units (ICUs) in the initial pandemic phase.

METHODS

This was a multicentre (nine site) observational study in Australia, linked with a national registry of critically ill patients with COVID-19. Adult patients with COVID-19 who were discharged to an acute ward following ICU admission were included over a 12-month period. Data are presented as n (%), median (interquartile range [IQR]), and odds ratio (OR [95% confidence interval {CI}]).

RESULTS

A total of 103 patients were included. Oral nutrition was the most common mode of nutrition (93 [93%]). In the ICU, there were 53 (52%) patients seen by a dietitian (median 4 [2-8] occasions) and malnutrition screening occurred in 51 (50%) patients most commonly with the malnutrition screening tool (50 [98%]). The odds of receiving a higher malnutrition screening tool score increased by 36% for every screening in the ICU (1st to 4th, OR: 1.39 [95% CI: 1.05-1.77] p = 0.018) (indicating increasing risk of malnutrition). On the ward, 51 (50.5%) patients were seen by a dietitian (median time to consult: 44 [22.5-75] hours post ICU discharge). The odds of dietetic consult increased by 39% every week while on the ward (OR: 1.39 [1.03-1.89], p = 0.034). Patients who received mechanical ventilation (MV) were more likely to receive dietetic input than those who never received MV.

CONCLUSIONS

During the initial phases of the COVID-19 pandemic in Australia, approximately half of the patients included were seen by a dietitian. An increased number of malnutrition screens were associated with a higher risk score in the ICU and likelihood of dietetic consult increased if patients received MV and as length of ward stay increased.

The influence of initial spinal cord haematoma and cord compression on neurological grade improvement in acute traumatic spinal cord injury: A prospective observational study

STUDY DESIGN

Prospective observational cohort study linked with administrative data.

OBJECTIVES

Magnetic Resonance Imaging (MRI) is routinely performed after traumatic spinal cord injury (TSCI), facilitating early, accurate diagnosis to optimize clinical management. Prognosis from early MRI post-injury remains unclear, yet if available could guide early intervention. The aim of this study was to determine the association of spinal cord intramedullary haematoma and/or extent of cord compression evident on initial spine MRI with neurological grade change after TSCI.

METHODS

Individuals with acute TSCI ≥16 years of age; MRI review. Neurological gradings (American Spinal Injury Association Impairment Scale (AIS)) were compared with initial MRI findings. Various MRI parameters were evaluated for prediction of neurological improvement pre-discharge.

RESULTS

120 subjects; 79% male, mean (SD) age 51.0 (17.7) years. Motor vehicle crashes (42.5%) and falls (40.0%) were the most common injury mechanisms. Intramedullary spinal cord haematoma was identified by MRI in 40.0% of patients and was associated with more severe neurologic injury (58.3% initially AIS A). Generalised linear regression showed higher maximum spinal cord compression (MSCC) was associated with lower likelihood of neurological improvement from initial assessment to follow up prior to rehabilitation discharge. Combined thoracic level injury, intramedullary haematoma, and MSCC > 25% resulted in almost 90% probability of pre-discharge AIS (grade A) remaining unchanged from admission assessment.

CONCLUSIONS

MRI is a vital tool for evaluating the severity and extent of TSCI, assisting in appropriate management decision-making early in TSCI patient care. This study adds to the body of knowledge assisting clinicians in prognostication.

Kinesiophobia, Knee Self-Efficacy, and Fear Avoidance Beliefs in People with ACL Injury: A Systematic Review and Meta-Analysis

BACKGROUND

To improve the understanding of the psychological impacts of anterior cruciate ligament (ACL) injury, a systematic review synthesizing the evidence on knee self-efficacy, fear avoidance beliefs and kinesiophobia following ACL injury is needed.

OBJECTIVE

The aim of this systematic review was to investigate knee self-efficacy, fear avoidance beliefs and kinesiophobia following ACL injury, and compare these outcomes following management with rehabilitation alone, early and delayed ACL reconstruction (ACLR).

METHODS

Seven databases were searched from inception to April 14, 2022. Articles were included if they assessed Tampa Scale of Kinesiophobia (TSK), Knee Self-Efficacy Scale (KSES), or Fear Avoidance Beliefs Questionnaire (FABQ). Risk of bias (RoB) was assessed using domain-based RoB tools (ROBINS-1, RoB 2, RoBANS), and GRADE-assessed certainty of evidence. Random-effects meta-analyses pooled outcomes, stratified by time post-injury (pre-operative, 3-6 months, 7-12 months, > 1-2 years, > 2-5 years, > 5 years).

RESULTS

Seventy-three studies (70% high RoB) were included (study outcomes: TSK: 55; KSES: 22; FABQ: 5). Meta-analysis demonstrated worse kinesiophobia and self-efficacy pre-operatively (pooled mean [95% CI], TSK-11: 23.8 [22.2-25.3]; KSES: 5.0 [4.4-5.5]) compared with 3-6 months following ACLR (TSK-11: 19.6 [18.7-20.6]; KSES: 19.6 [18.6-20.6]). Meta-analysis suggests similar kinesiophobia > 3-6 months following early ACLR (19.8 [4.9]) versus delayed ACLR (17.2 [5.0]). Only one study assessed outcomes comparing ACLR with rehabilitation only.

CONCLUSIONS

Knee self-efficacy and kinesiophobia improved from pre-ACLR to 3-6 months following ACLR, with similar outcomes after 6 months. Since the overall evidence was weak, there is a need for high-quality observational and intervention studies focusing on psychological outcomes following ACL injury.

Conservative or liberal oxygen therapy for mechanically ventilated adults with acute brain pathologies: A post-hoc subgroup analysis

PURPOSE

To compare the effect of conservative vs. liberal oxygen therapy in mechanically ventilated adults in the intensive care unit (ICU) with non-hypoxic ischemic encephalopathy (HIE) acute brain pathologies.

MATERIALS AND METHODS

Post-hoc analysis of data from 217 patients with non-HIE acute brain pathologies included in the ICU Randomized Trial Comparing Two Approaches to OXygen therapy (ICU-ROX).

RESULTS

Patients allocated to conservative oxygen spent less time with oxygen saturation ≥ 97% (50.5 [interquartile range (IQR), 18.5-119] vs. 82 h [IQR, 38-164], absolute difference, -31.5 h; 95%CI, -59.6 to -3.4). At 180 days, 38 of 110 conservative oxygen patients (34.5%) and 28 of 104 liberal oxygen patients (26.9%) had died (absolute difference, 7.6 percentage points; 95%CI, -4.7 to 19.9 percentage points; P = 0.23; interaction P = 0.02 for non-HIE acute brain pathologies vs. HIE; interaction P = 0.53 for non-HIE acute brain pathologies vs. non-neurological conditions).

CONCLUSIONS

In this post-hoc analysis, patients admitted to the ICU with non-HIE acute brain pathologies treated with conservative oxygen therapy did not have significantly lower mortality than those treated with liberal oxygen. A trial with adequate statistical power is needed to determine whether our day 180 mortality point estimate of treatment effect favoring liberal oxygen therapy indicates a true effect.

Oral vaccination of dogs with a monovalent live-avirulent vaccine confers 1 year of immunity against Bordetella bronchiseptica challenge

This experimental challenge study assessed immune protection 1 year after a single dose of live-attenuated oral Bordetella bronchiseptica (Bb) vaccine in dogs. Forty Bb-seronegative 7-9-week-old puppies were randomly assigned at Day 0 to receive a single oral dose of either Bb vaccine (n = 20; vaccinated group) or sterile water (n = 20; control group). Groups were housed separately until comingling 1 day pre-challenge (Day 365). Challenge with virulent aerosolized Bb occurred at Day 366. Clinical scores were obtained at Days 1-7, and 366-380. Bb microagglutination test (MAT) titers were obtained at Days -7, 0, monthly post-vaccination, and Days 358, 365, and 380. Nasal swabs were collected for microbiological assessment at Days -7, 0, 365, and 367-380. Oral Bb vaccination was not associated with side effects. Pre-challenge, vaccinated dogs developed persistent Bb MAT titers and control dogs remained seronegative. Post-challenge, duration of cough was longer in control dogs (least square means [LSM], 8.6 days) than vaccinated dogs (LSM, 1.5 days; P < 0.0001), with more control dogs having cough on 2 or more consecutive days (control group, n = 17/19, 89.5%; vaccinated group, n = 3/19, 15.8%; P = 0.0011). Post-challenge, Bb shedding occurred in all control dogs and 5/19 (26%) vaccinated dogs. Average duration of Bb shedding was longer in the control group (11.9 days vs. 0.6 days; P < 0.0001) and nasal Bb loads were higher in the control group (P < 0.00001). Orally administered Bb vaccine stimulated immunity that was still protective against virulent Bb challenge after 1 year.

Psychological Resources, Constructive Conflict Management Behaviors, and Depressive Symptoms: A Dyadic Analysis

This study investigated the longitudinal associations between mastery, conflict management behaviors, and depressive symptoms using an actor-partner interdependence model with 371 middle-aged couples over a span of 24 years. Results indicated that for both husbands and wives, individuals who possessed higher levels of mastery generally displayed more constructive conflict management behaviors during marital conflicts in middle years. In turn, individuals with more constructive behaviors averaged fewer depressive symptoms in their later adulthood. A partner effect was also noted, as individuals' constructive behaviors were linked to their spouse's depressive symptoms. This finding emphasizes the importance of utilizing a dyadic context to understand intra-individual and inter-individual (or crossover) influences between husbands and wives in enduring marriages. A better understanding of how couples affect each other's mental health can inform the development and implementation of health promotion interventions and prevention efforts targeting middle-aged couples.

Conservative oxygen therapy for mechanically ventilated adults with suspected hypoxic ischaemic encephalopathy

PURPOSE

Liberal use of oxygen may contribute to secondary brain injury in patients with hypoxic-ischaemic encephalopathy (HIE). However, there are limited data on the effect of different oxygen regimens on survival and neurological disability in HIE patients.

METHODS

We undertook a post-hoc analysis of the 166 patients with suspected HIE enrolled in a trial comparing conservative oxygen therapy with usual oxygen therapy in 1000 mechanically ventilated ICU patients. The primary endpoint for the current analysis was death or unfavourable neurological outcome at day 180. Key secondary outcomes were day 180 mortality, and cause-specific mortality.

RESULTS

Patients with HIE allocated to conservative oxygen spent less time in the ICU with an SpO₂ ≥ 97% (26 h [interquartile range (IQR) 13-45 vs. 35 h [IQR 19-70], absolute difference, 9 h; 95% CI - 21.4 to 3.4). A total of 43 of 78 patients (55.1%) assigned to conservative oxygen and 49 of 72 patients (68.1%) assigned to usual oxygen died or had an unfavourable neurological outcome at day 180; odds ratio 0.58; 95% CI 0.3-1.12; P = 0.1 adjusted odds ratio 0.54; 95% CI 0.23-1.26; P = 0.15. A total of 37 of 86 patients (43%) assigned to conservative oxygen and 46 of 78 (59%) assigned to usual oxygen had died by day 180; odds ratio 0.53; 95% CI 0.28-0.98; P = 0.04; adjusted odds ratio 0.56; 95% CI 0.25-1.23; P = 0.15. Cause-specific mortality was similar by treatment group.

CONCLUSIONS

Conservative oxygen therapy was not associated with a statistically significant reduction in death or unfavourable neurological outcomes at day 180. The potential for important benefit or harm from conservative oxygen therapy in HIE patients is not excluded by these data.

Maximal Recruitment Open Lung Ventilation in Acute Respiratory Distress Syndrome (PHARLAP). A Phase II, Multicenter Randomized Controlled Clinical Trial

Rationale: Open lung ventilation strategies have been recommended in patients with acute respiratory distress syndrome (ARDS).Objectives: To determine whether a maximal lung recruitment strategy reduces ventilator-free days in patients with ARDS.Methods: A phase II, multicenter randomized controlled trial in adults with moderate to severe ARDS. Patients received maximal lung recruitment, titrated positive end expiratory pressure and further Vt limitation, or control "protective" ventilation.Measurements and Main Results: The primary outcome was ventilator-free days at Day 28. Secondary outcomes included mortality, barotrauma, new use of hypoxemic adjuvant therapies, and ICU and hospital stay. Enrollment halted October 2, 2017, after publication of ART (Alveolar Recruitment for Acute Respiratory Distress Syndrome Trial), when 115 of a planned 340 patients had been randomized (57% male; mean age, 53.6 yr). At 28 days after randomization, there was no difference between the maximal lung recruitment and control ventilation strategies in ventilator-free days (median, 16 d [interquartile range (IQR), 0-21 d], n = 57, vs. 14.5 d [IQR, 0-21.5 d], n = 56; P = 0.95), mortality (24.6% [n = 14/56] vs. 26.8% [n = 15/56]; P = 0.79), or the rate of barotrauma (5.2% [n = 3/57] vs. 10.7% [n = 6/56]; P = 0.32). However, the intervention group showed reduced use of new hypoxemic adjuvant therapies (i.e., inhaled nitric oxide, extracorporeal membrane oxygenation, prone; median change from baseline 0 [IQR, 0-1] vs. 1 [IQR, 0-1]; P = 0.004) and increased rates of new cardiac arrhythmia (n = 17 [29%] vs. n = 7 [13%]; P = 0.03).Conclusions: Compared with control ventilation, maximal lung recruitment did not reduce the duration of ventilation-free days or mortality and was associated with increased cardiovascular adverse events but lower use of hypoxemic adjuvant therapies.Clinical trial registered with www.clinicaltrials.gov (NCT01667146).

Conservative Oxygen Therapy during Mechanical Ventilation in the ICU

BACKGROUND

Patients who are undergoing mechanical ventilation in the intensive care unit (ICU) often receive a high fraction of inspired oxygen (Fio₂) and have a high arterial oxygen tension. The conservative use of oxygen may reduce oxygen exposure, diminish lung and systemic oxidative injury, and thereby increase the number of ventilator-free days (days alive and free from mechanical ventilation).

METHODS

We randomly assigned 1000 adult patients who were anticipated to require mechanical ventilation beyond the day after recruitment in the ICU to receive conservative or usual oxygen therapy. In the two groups, the default lower limit for oxygen saturation as measured by pulse oximetry (Spo₂) was 90%. In the conservative-oxygen group, the upper limit of the Spo₂ alarm was set to sound when the level reached 97%, and the Fio₂ was decreased to 0.21 if the Spo₂ was above the acceptable lower limit. In the usual-oxygen group, there were no specific measures limiting the Fio₂ or the Spo₂. The primary outcome was the number of ventilator-free days from randomization until day 28.

RESULTS

The number of ventilator-free days did not differ significantly between the conservative-oxygen group and the usual-oxygen group, with a median duration of 21.3 days (interquartile range, 0 to 26.3) and 22.1 days (interquartile range, 0 to 26.2), respectively, for an absolute difference of -0.3 days (95% confidence interval [CI], -2.1 to 1.6; P = 0.80). The conservative-oxygen group spent more time in the ICU with an Fio₂ of 0.21 than the usual-oxygen group, with a median duration of 29 hours (interquartile range, 5 to 78) and 1 hour (interquartile range, 0 to 17), respectively (absolute difference, 28 hours; 95% CI, 22 to 34); the conservative-oxygen group spent less time with an Spo₂ exceeding 96%, with a duration of 27 hours (interquartile range, 11 to 63.5) and 49 hours (interquartile range, 22 to 112), respectively (absolute difference, 22 hours; 95% CI, 14 to 30). At 180 days, mortality was 35.7% in the conservative-oxygen group and 34.5% in the usual-oxygen group, for an unadjusted odds ratio of 1.05 (95% CI, 0.81 to 1.37).

CONCLUSIONS

In adults undergoing mechanical ventilation in the ICU, the use of conservative oxygen therapy, as compared with usual oxygen therapy, did not significantly affect the number of ventilator-free days. (Funded by the Health Research Council of New Zealand; ICU-ROX Australian and New Zealand Clinical Trials Registry number, ACTRN12615000957594.).

Conservative oxygen therapy for mechanically ventilated adults with sepsis: a post hoc analysis of data from the intensive care unit randomized trial comparing two approaches to oxygen therapy (ICU-ROX)

PURPOSE

Sepsis is a common reason for intensive care unit (ICU) admission and mortality in ICU patients. Despite increasing interest in treatment strategies limiting oxygen exposure in ICU patients, no trials have compared conservative vs. usual oxygen in patients with sepsis.

METHODS

We undertook a post hoc analysis of the 251 patients with sepsis enrolled in a trial that compared conservative oxygen therapy with usual oxygen therapy in 1000 mechanically ventilated ICU patients. The primary end point for the current analysis was 90-day mortality. Key secondary outcomes were cause-specific mortality, ICU and hospital length of stay, ventilator-free days, vasopressor-free days, and the proportion of patients receiving renal replacement therapy in the ICU.

RESULTS

Patients with sepsis allocated to conservative oxygen therapy spent less time in the ICU with an SpO₂ ≥ 97% (23.5 h [interquartile range (IQR) 8-70] vs. 47 h [IQR 11-93], absolute difference, 23 h; 95% CI 8-38), and more time receiving an FiO₂ of 0.21 than patients allocated to usual oxygen therapy (20.5 h [IQR 1-79] vs. 0 h [IQR 0-10], absolute difference, 20 h; 95% CI 14-26). At 90-days, 47 of 130 patients (36.2%) assigned to conservative oxygen and 35 of 120 patients (29.2%) assigned to usual oxygen had died (absolute difference, 7 percentage points; 95% CI - 4.6 to 18.6% points; P = 0.24; interaction P = 0.35 for sepsis vs. non-sepsis). There were no statistically significant differences between groups for secondary outcomes but point estimates of treatment effects consistently favored usual oxygen therapy.

CONCLUSIONS

Point estimates for the treatment effect of conservative oxygen therapy on 90-day mortality raise the possibility of clinically important harm with this intervention in patients with sepsis; however, our post hoc analysis was not powered to detect the effects suggested and our data do not exclude clinically important benefit or harm from conservative oxygen therapy in this patient group.

CLINICAL TRIALS REGISTRY

ICU-ROX Australian and New Zealand Clinical Trials Registry number ACTRN12615000957594.

SUN-174 Severe Insulin Resistance and Diabetic Ketoacidosis after Brentuximab Vendotin and Cyclosporin Treatment

Introduction: Brentuximab Vendotin(BV) is antibody-drug conjugate that selectively delivers cytotoxic agent, monomethyl auristatin E, targeting cells expressing surface CD30, treatment approved for refractory Hodgkin’s lymphoma. Previous research suggested MDR1 inhibition (cyclosporine) can overcome BV resistance. Case: 23 year old male with relapsed and refractory classical Hodgkin lymphoma underwent clinical trial with BV and Cyclosporin( CyA). He was given one dose of BV( 1.8mg/kg) and CyA ( 725mg 2 times a day for 5 days). A week after BV and 3 days after the last dose of CyA, patient had acute onset of hyperglycemia and ketoacidosis; glucose 435 mg/dL, bicarbonate 14 mmol/L, anion gap 14( 8-14), beta hydroxybutyrate 40.3 mg/dL (0.0-3.0 mg/dL), urine ketone +3, C-peptide 9.0 ng/ml (0.8-3.5 ng/ml). Serum cyclosporine level was high as 453 ng/ml (150-300ng/ml) at the time of presentation, which was reduced to 116 ng/ml within a week. He had no previous diabetes history. His severe hyperglycemia and metabolic acidosis persisted after aggressive hydration and multiple daily insulin injections. He was started on modified intravenous insulin infusion protocol. Within 24 hours, his glycemic control was improved at goal requiring average 34 units/h of regular insulin with NPO status. This was transitioned to U500 regular insulin divided dose injection every 8 hours with holding criteria. 10 days after initial clinical presentation, patient's insulin requirement was abruptly reduced and eventually discontinued. Patient was discharged and glucose level remained within reference range (80-128 mg/dl) without additional medical management from follow-up. Patient had completed given clinical trial with reduced dose of BV and CyA, and there was no further similar episode. During the hospital course, underlying endocrine disease related to insulin resistance was ruled out including thyroid, glucagon, cortisol, catecholamine, or growth hormone excess. Autoimmune workup was negative except elevated ESR. Insulin autoantibody panels were negative. Pancreatitis and infections were also ruled out. Lymphocytes were reduced and monocytes were increased in CBC during the episode. Peripheral blood mononuclear cell (PBMC) analysis by flow cytometry showed that absolute B and T cell counts were low but in the residual CD4+ and CD8+ T cells, expression of CD25 and PD-1 was increased. Major portion of the PBMC did not stain with our standard immune phenotype panel, which may include plasma cells, NKT, or dendritic cells. Discussion: Adverse events ≥ Grade 3 hyperglycemia (12%) has been reported with BV treatment. On the other hand, CyA is known to be related to insulin resistance as well. This is the first case report of a patient who developed rare condition of severe insulin resistance and diabetic ketoacidosis in the context of hyperinsulinemia likely due to impaired insulin signaling induced by BV and CyA.

Production of Antigen-Specific Human CD4+ T Cell Lines and Clones

Methodologies to generate single antigen-specific T cells are based on the T cell specificity, activation, or other subsequent functional measures. One of the most powerful tools to isolate human CD4⁺ T cell clones is utilization of MHC Class II tetramers. Flow cytometer-based tetramer technology mimics the recognition of the specific antigenic peptide in the context of HLA class II (tetramer) by the T cell receptor. MHC class II tetramers, which can be exogenously loaded to contain any peptide of interest that binds to them (T cell epitopes), provide a valuable tool for detection of T cells in the peripheral blood or the tissue that are specific for antigens from different viruses, tumors, or self-proteins (autoimmunity). Generation of T cell clones with a defined antigen specificity allows for a deeper characterization and functional assessment at single cell level. This is important for determination of the epitope specificity and functional phenotype of the disease associated T cells. Single cell cloning can be utilized in the direct sequencing of the T cell receptor alpha/beta pairs that are prevalent in the disease and therefore provides a platform for T cell receptor engineering, which has applications in the immunotherapy.

The influence of mastery on mother's health in middle years: Moderating role of stressful life context

Using data from 416 middle-aged mothers gathered over the course of a decade, this study examined the influence of mastery trajectories (the initial level and change), on change in physical health. Mastery is defined as one's ability to control and influence his/her life and environment to reach a desired outcome or goal. Both the initial level and change in mastery from 1991 to 1994 were associated with decreased physical health problems over the middle years (1991-2001). Contextual moderation of this association by stressful life contexts including negative life events and work-family conflict was investigated. Moderation analysis showed that under conditions of low contextual life stressors, the level and increase in mastery significantly contributed to decreases in physical health problems in middle-aged mothers. Alternatively, conditions of high contextual life stressors inhibited the ability of mastery to influence physical health of mothers, suggesting that the positive health impact of mastery on physical health is mitigated by stressful life experiences. Implications for the need to maintain important personal resources, such as mastery, during times of stress are discussed.

Tantalum trabecular metal implants in anterior cervical corpectomy and fusion: 2-year prospective analysis

Anterior cervical decompression for two or more cervical spondylotic levels can be performed using either multiple anterior cervical discectomies and fusion or anterior cervical corpectomy and fusion (ACCF). A variety of options for ACCF implants exist but to our knowledge, there is no clinical data for the use of tantalum trabecular metal implants (TTMI) for ACCF. A retrospective review was performed of prospectively collected data for ten patients undergoing ACCF with TTMI between 2011 and 2012. Radiological outcome was assessed by measuring the change in cervical (C) lordosis (fusion Cobb and C2-C7 Cobb), graft subsidence (anterior/posterior, determined by the subsidence of anterior/posterior body height of fused segments; cranial/caudal, determined by the cranial/caudal plate-to-disc distances) and rate of fusion using lateral cervical X-rays of patients at 0, 6, 12 and 24months post-operatively. The Neck Disability Index (NDI) assessed clinical outcome pre-operatively and at 6, 12 and 24months post-operatively. Cervical lordosis (Cobb angle of fused segment) was 5.2° (± 4.2°) at 0months and 6.0° (± 5.7°) at 24months post-operatively. Graft subsidence was observed to occur at 6months post-operatively and continued throughout follow-up. Anterior, posterior and caudal subsidence occurred more in the first 12months post-operatively than in the following 12months (p<0.05). Average pre-operative NDI was 45%. Average NDIs were 18%, 13% and 10% at 6, 12 and 24months post-operatively, respectively. ACCF patients treated with TTMI demonstrated stable cervical lordosis over 2years of follow-up and 100% fusion rates after 2years. Measures of subsidence appeared to decrease with time. Patients experienced improved clinical outcomes over the 2-year period.

HYSTEROSALPINGOGRAPHY AND LAPAROSCOPY IN EVALUATING FALLOPIAN TUBES IN THE MANAGEMENT OF INFERTILITY IN COTONOU, BENIN REPUBLIC

INTRODUCTION

Hysterosalpingography, along with laparoscoy, are the most requested examinations for tubal factor exploration for infertility, in developing countries.

OBJECTIVE

To compare the results of hysperosalpingography and laparoscopy in patients assessed for infertility.

PATIENTS & METHODS

This was a 5 years retrospective, descriptive study done at the Obstetrics and Gynecology Clinic of the HKM Centre, National University Hospital. All the patients admitted for infertility of tubal origin were included. These included 96 patients who had undergone hysterosalpingography followed by laparoscopy. The analysis was done with the SPSS version 12.0.1.

RESULT

The mean age of the patients was 33.3 years. Infertility was primary in 66.3% of cases and secondary in 33.7% of cases and the average duration was 48.9 months. Hysterosalpingography diagnosed 9.37% of proximal tubal obstruction while laparoscopy diagnosed same in 17.71%. Besides pelvic adhesive bands seen in 33.33% of cases, laparoscopy was able to visualize patent tubes with some pathology in 11.46%, and pelvic endometriosis in 6.25% of cases.

CONCLUSION

The results of HSG and those of laparoscopy are complementary in tubal infertility evaluation. While HSG seems to be reliable when the tubes are patent, laparoscopy helps to reveal false tubal obstructions observed with HSG, and also helps in the diagnosis of pelvic adhesive bands and endometriosis.

The effects of an obesogenic diet during pregnancy on fetal growth and placental gene expression are gestation dependent

Exposure to overnutrition in utero may increase offspring cardiometabolic disease risk. A mouse model of maternal exposure to an obesogenic diet (DIO) was used to determine effects on fetal and placental weight and gene expression in mid- and late gestation. DIO altered placental gene expression in mid-gestation without differences in fetal or placental weights. Weight gain was attenuated in DIO dams in late gestation and male pup weight was reduced, however there were no persistent changes in placental gene expression. Differences in maternal weight gain and/or specific dietary components may impact on fetal and placental growth and later disease risk.

Vaccination of dogs with Duramune DAPPi+LC protects against pathogenic canine parvovirus type 2c challenge

In this study, we determined whether vaccination with Duramune DAPPi+LC containing canine parvovirus (CPV) type 2b protects against challenge with virulent CPV antigenic type 2c. Seven healthy dogs, seronegative for CPV2, were enrolled into two treatment groups; five were vaccinated twice, 21 days apart, with minimum titre vaccine, and two were given saline. Dogs were challenged with CPV 2c three weeks later. Clinical observations, body weight and rectal temperature measurements, blood samples for serology and white blood cell counts and faecal samples for virus excretion were collected. Control dogs remained seronegative until challenge; vaccinated dogs seroconverted and were positive for antibodies to CPV2 from day 21. Four days after challenge, clinical signs associated with parvovirus infection (vomiting, paroxysmal shivering, depression, loose stools) were observed in the control dogs. Both animals were withdrawn from the study for welfare reasons one day later. On day 47, leucopenia was observed in controls, with white blood cell counts less than 50 per cent prechallenge values. No specific clinical sign of parvovirus infection were observed in the vaccinated dogs, nor was (detectable) challenge virus shed in faeces suggesting that antibodies generated contributed sterilising immunity. We conclude that vaccination of dogs with Duramune DAPPi+LC protects against challenge with a virulent field strain of CPV 2c.

Immunocastration of Bos indicus x Brown Swiss bulls in feedlot with gonadotropin-releasing hormone vaccine Bopriva provides improved performance and meat quality

The objective of this study was to determine the effects of a GnRH vaccine on feedlot performance and meat quality in Bos indicus Zebu × Brown Swiss bulls. The study was a 2 × 2 factorial arrangement of treatments with 1,600 bulls allocated by BW into 4 groups of ≈ 400 animals. The GnRH vaccine (Bopriva) was injected on d 0 and 42, and anabolic implants given on d 0 (Component E-S) and d 84 (Synovex Choice). Group designations were: Con = placebo control; Imp = implants alone; Vac = GnRH vaccine alone; and Vac+Imp = GnRH vaccine together with implants. The second GnRH vaccination at d 42 resulted in elevated titers of IgG antibody and suppressed concentrations of testosterone in vaccinated groups (Vac and Vac+Imp) at d 56 (P < 0.001), with titers and suppressed testosterone persisting to d 147 (P < 0.001). Groups Vac and Vac+Imp had reduced testes weights at slaughter on d 147 (P < 0.001). Bulls in group Vac were not different in final BW, HCW, or ADG (d 42 to 147) relative to bulls in group Con. Bulls in group Vac+Imp had greater final BW than bulls in group Imp (P = 0.008) and greater BW than bulls in group Vac and group Con (P < 0.001). The HCW of Vac+Imp bulls was greater than the Vac or Con bulls (P < 0.001) but was not different to the Imp bulls (P = 0.294). Improved ADG was obtained by vaccination with the GnRH vaccine, in the presence of implants (group Vac+Imp compared with group Imp, P < 0.001) or absence of implants (group Vac compared with group Con, P = 0.028). Meat quality of bulls receiving the GnRH vaccine was improved irrespective of implant status, with a 1.6- to 2.6-fold increase in the proportion of bulls in groups Vac and Vac+Imp, respectively, grading as USDA Choice (P < 0.002) and with greater fat depth at the 12th rib (P < 0.001). Meat tenderness was improved in the vaccine groups (Vac and Vac+Imp) compared with groups Con and Imp (P < 0.004). Use of the GnRH vaccine Bopriva in Bos indicus × Brown Swiss bulls finishing in a feedlot under Mexican husbandry conditions can provide improved performance in combination with implants (increased BW and ADG) and improved meat quality, with or without implants, and in particular, better USDA carcass grading and loin fat cover.

P2-08-01: Impact of Aromatase Inhibitors on Background Parenchymal Enhancement and Amount of Fibroglandular Tissue on Breast MRI

Background: On breast MRI, background parenchymal enhancement (BPE) and volume of fibroglandular tissue (FGT) have been shown to reflect a patient's hormonal status. Tamoxifen has been shown to reduce mammographic breast density and may serve as an early predictor of response in the prevention setting (Cuzick, JNCI 2011). We have shown that adjuvant tamoxifen can reduce BPE in the unaffected breast in women with breast cancer. We hypothesize that aromatase inhibitor (AI) induced endocrine changes in breast tissue should also be evident and therefore we performed a study to evaluate whether adjuvant AI therapy influences BPE or amount of FGT in the contralateral breast.

Methods: An electronic medical record review identified 856 postmenopausal women with stage I-III breast cancer who had at least two breast MRIs and took adjuvant AI treatment. A retrospective chart review was conducted to select those patients without a history of prior tamoxifen or raloxifene treatment who had a MRI of the contralateral breast both before and during 6 to 12 months of AI treatment. After exclusion of all irradiated breasts, 168 women were eligible. MRIs were performed between August 1999 and June 2010. Two radiologists who were blind to AI treatment status, independently rated level of BPE and amount of FGT using categorical scales: BPE — Minimal, Mild, Moderate, Marked; FGT — Fatty, Scattered, Heterogeneously Dense, Dense (based on proposed BIRADS criteria for BPE and on ACR criteria for FGT). Blinded side-by-side direct comparison evaluated whether there was a category change between the two MRIs. A consensus was reached in cases of disagreement. The Wilcoxon signed-rank test was used to assess changes in rating categories for BPE and FGT between before and during AI breast MRIs. A waiver of authorization was granted by the institutional review board for this study.

Results: In this study 127/168 (76%) women were treated with anastrozole, 33/168 (20%) with letrozole and 8/168 (5%) with exemestane. Based on the blinded side-by-side comparison, a category (or more) decrease in BPE occurred during treatment with AIs (p&lt;0.0001). There was an overall shift from higher to lower degree of BPE in 35% (45/127) of the women taking anastrozole while a category increase occurred in only one woman (1%; p &lt;0.0001). A similar result was seen in the women taking letrozole [45% (15/33) had a decrease versus 3% (1/33) an increase; p=0.0003] and exemestane [25% (2/8) had a decrease versus 12.5% (1/8) an increase; p=0.50]. For FGT a category decrease occurred in 5% (6/127) of anastrozole users while no increase occurred [0% (0/127), p=0.016]. The respective numbers for letrozole were 3% (1/33) and 0% (0/33), and nobody on exemestane had a change in FGT.

Conclusions: After 6 to 12 months of treatment with adjuvant AIs, there was a statistically significant category (or more) decrease in BPE. BPE is more sensitive than FGT to changes in normal breast stroma that occur during adjuvant treatment with AIs and BPE may be a marker of anti-hormonal activity in the breasts.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-01.

Polychlorinated biphenyl-77 induces adipocyte differentiation and proinflammatory adipokines and promotes obesity and atherosclerosis

BACKGROUND

Obesity, an inflammatory condition linked to cardiovascular disease, is associated with expansion of adipose tissue. Highly prevalent coplanar polychlorinated biphenyls (PCBs) such as 3,3',4,4'-tetrachlorobiphenyl (PCB-77) accumulate in adipose tissue because of their lipophilicity and increase with obesity. However, the effects of PCBs on adipocytes, obesity, and obesity-associated cardiovascular disease are unknown.

OBJECTIVES

In this study we examined in vitro and in vivo effects of PCB-77 on adipocyte differentiation, proinflammatory adipokines, adipocyte morphology, body weight, serum lipids, and atherosclerosis.

METHODS

PCB-77 or 2,2',4,4,5,5'-hexachlorobiphenyl (PCB-153) was incubated with 3T3-L1 adipocytes either during differentiation or in mature adipocytes. Concentration-dependent effects of PCB-77 were contrasted with those of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). For in vivo studies, we treated C57BL/6 wild-type (WT) or aryl hydrocarbon receptor (AhR)(-/-) mice with vehicle or PCB-77 (49 mg/kg, by intraperitoneal injection) and examined body weight gain. In separate studies, we injected ApoE(-/-) mice with vehicle or PCB-77 over a 6-week period and examined body weight, adipocyte size, serum lipids, and atherosclerosis.

RESULTS

Low concentrations of PCB-77 or TCDD increased adipocyte differentiation, glycerol-3-phosphate dehydrogenase activity, and expression of peroxisome proliferator-activated receptor gamma, whereas higher concentrations inhibited adipocyte differentiation. Effects of PCB-77 were abolished by the AhR antagonist alpha-naphthoflavone. PCB-77 promoted the expression and release of various proinflammatory cytokines from 3T3-L1 adipocytes. Administration of PCB-77 increased body weight gain in WT but not AhR(-/-) mice. ApoE(-/-) mice injected with PCB-77 exhibited greater body weight, adipocyte hypertrophy, serum dyslipidemia, and augmented atherosclerosis.

CONCLUSIONS

Our findings suggest that PCB-77 may contribute to the development of obesity and obesity-associated atherosclerosis.

Evolution of the male-determining gene SRY within the cat family Felidae

In most placental mammals, SRY is a single-copy gene located on the Y chromosome and is the trigger for male sex determination during embryonic development. Here, we present comparative genomic analyses of SRY (705 bp) along with the adjacent noncoding 5' flank (997 bp) and 3' flank (948 bp) in 36 species of the cat family Felidae. Phylogenetic analyses indicate that the noncoding genomic flanks and SRY closely track species divergence. However, several inconsistencies are observed in SRY. Overall, the gene exhibits purifying selection to maintain function (omega = 0.815) yet SRY is under positive selection in two of the eight felid lineages. SRY has low numbers of nucleotide substitutions, yet most encode amino acid changes between species, and four different species have significantly altered SRY due to insertion/deletions. Moreover, fixation of nonsynonymous substitutions between sister taxa is not consistent and may occur rapidly, as in the case of domestic cat, or not at all over long periods of time, as observed within the Panthera lineage. The former resembles positive selection during speciation, and the latter purifying selection to maintain function. Thus, SRY evolution in cats likely reflects the different phylogeographic histories, selection pressures, and patterns of speciation in modern felids.

Expressed in the yeast Saccharomyces cerevisiae, human ERK5 is a client of the Hsp90 chaperone that complements loss of the Slt2p (Mpk1p) cell integrity stress-activated protein kinase

ERK5 is a mitogen-activated protein (MAP) kinase regulated in human cells by diverse mitogens and stresses but also suspected of mediating the effects of a number of oncogenes. Its expression in the slt2Delta Saccharomyces cerevisiae mutant rescued several of the phenotypes caused by the lack of Slt2p (Mpk1p) cell integrity MAP kinase. ERK5 is able to provide this cell integrity MAP kinase function in yeast, as it is activated by the cell integrity signaling cascade that normally activates Slt2p and, in its active form, able to stimulate at least one key Slt2p target (Rlm1p, the major transcriptional regulator of cell wall genes). In vitro ERK5 kinase activity was abolished by Hsp90 inhibition. ERK5 activity in vivo was also lost in a strain that expresses a mutant Hsp90 chaperone. Therefore, human ERK5 expressed in yeast is an Hsp90 client, despite the widely held belief that the protein kinases of the MAP kinase class are non-Hsp90-dependent activities. Two-hybrid and protein binding studies revealed that strong association of Hsp90 with ERK5 requires the dual phosphorylation of the TEY motif in the MAP kinase activation loop. These phosphorylations, at positions adjacent to the Hsp90-binding surface recently identified for a number of protein kinases, may cause a localized rearrangement of this MAP kinase region that leads to creation of the Hsp90-binding surface. Complementation of the slt2Delta yeast defect by ERK5 expression establishes a new tool with which to screen for novel agonists and antagonists of ERK5 signaling as well as for isolating mutant forms of ERK5.

A two-hybrid screen of the yeast proteome for Hsp90 interactors uncovers a novel Hsp90 chaperone requirement in the activity of a stress-activated mitogen-activated protein kinase, Slt2p (Mpk1p)

The Hsp90 chaperone cycle catalyzes the final activation step of several important eukaryotic proteins (Hsp90 "clients"). Although largely a functional form of Hsp90, an Hsp90-Gal4p DNA binding domain fusion (Hsp90-BD) displays no strong interactions in the yeast two-hybrid system, consistent with a general transience of most Hsp90-client associations. Strong in vivo interactions are though detected when the E33A mutation is introduced into this bait, a mutation that should arrest Hsp90-client complexes at a stage where the client is stabilized, yet prevented from attaining its active form. This E33A mutation stabilized the two-hybrid interactions of the Hsp90-BD fusion with approximately 3% of the Saccharomyces cerevisiae proteome in a screen of the 6,000 yeast proteins expressed as fusions to the Gal4p activation domain (AD). Among the detected interactors were the two stress-activated mitogen-activated protein (MAP) kinases of yeast, Hog1p and Slt2p (Mpk1p). Column retention experiments using wild-type and mutant forms of Hsp90 and Slt2p MAP kinase, as well as quantitative measurements of the effects of stress on the two-hybrid interaction of mutant Hsp90-BD and AD-Slt2p fusions, revealed that Hsp90 binds exclusively to the dually Thr/Tyr-phosphorylated, stress-activated form of Slt2p [(Y-P,T-P)Slt2p] and also to the MAP kinase domain within this (Y-P,T-P)Slt2p. Phenotypic analysis of a yeast mutant that expresses a mutant Hsp90 (T22Ihsp82) revealed that Hsp90 function is essential for this (Y-P,T-P)Slt2p to activate one of its downstream targets, the Rlm1p transcription factor. The interaction between Hsp90 and (Y-P,T-P)Slt2p, characterized in this study, is probably essential in this Hsp90 facilitation of the Rlm1p activation by Slt2p.

Investigating the protein-protein interactions of the yeast Hsp90 chaperone system by two-hybrid analysis: potential uses and limitations of this approach

The Hsp90 chaperone cycle involves sequential assembly of different Hsp90-containing multiprotein complexes, the accessory proteins ("cochaperones") that are associated with these complexes being exchanged as the cycle proceeds from its early to its late stages. To gain insight as to whether the 2-hybrid system could be used to probe the interactions of this Hsp90 system, yeast transformants were constructed that express the Gal4p deoxyribonucleic acid-binding domain (BD) fused to the 2 Hsp90 isoforms and the various Hsp90 system cochaperones of yeast. These "bait" fusions were then introduced by mating into other transformants expressing nearly all the 6000 proteins of yeast expressed as fusions to the Gal4p activation domain (AD). High throughput 2-hybrid screening revealed the ability of Hsp90 and Hsp90 system cochaperones to engage in stable interactions in vivo, both with each other and with the various other proteins of the yeast proteome. Consistent with the transience of most chaperone associations, interactions to Hsp90 itself were invariably weak and generally influenced by stress. Mutations within a Hsp90-BD bait fusion and an AD-Cdc37 "prey" fusion were used to provide in vivo confirmation of the in vitro data that shows that Cdc37p is interacting with the "relaxed" conformation of Hsp90 and also to provide indications that Cdc37p needs to be phosphorylated at its N-terminus for any appreciable interaction with Hsp90. A number of potentially novel cochaperone interactions were also identified, providing a framework for these to be analyzed further using other techniques.

Prevalence of polycystic ovaries in women with self-reported symptoms of oligomenorrhoea and/or hirsutism: Northern Finland Birth Cohort 1966 Study

BACKGROUND

The aim of this study was to investigate the prevalence of polycystic ovaries (PCO) among women with self-reported oligomenorrhoea and/or hirsutism and to see whether women with symptoms and PCO have less favourable levels of biochemical markers than controls or women with symptoms and normal ovaries.

METHODS

The ultrasonographic ovarian morphology and the hormonal and metabolic profile of female cases with self-reported symptoms typical of polycystic ovary syndrome (PCOS) (n = 196) and asymptomatic controls (n = 67) at the age of 31 years were examined in a general population-based Northern Finland Birth Cohort 1966.

RESULTS

The prevalence of PCO (37.3 versus 18.2%; P = 0.004) was significantly higher in the cases (oligomenorrhoea and/or hirsutism) than in the controls. PCO morphology was detected in 18.4% of those who reported only hirsutism, in 47.9% of those reporting only oligomenorrhoea, and in 70.4% of those reporting both symptoms. In the cases with PCO compared to (i) the controls and (ii) the cases without PCO, body mass index (P = 0.026 and P = 0.011), ovarian volume [right P = 0.001, left P = 0.208 (non-significant) and right P < 0.001, left P = 0.022], mean follicle number (P < 0.001 and P < 0.001), testosterone (P = 0.063 and P = 0.029), free androgen index (P = 0.007 and P = 0.013) and insulin (P = 0.033 and P = 0.040) were higher, and sex hormone-binding globulin (P = 0.039 and P = 0.068) and glucose:insulin ratio (P = 0.060 and P = 0.054) lower. Cases with PCO also had higher waist:hip ratio (P = 0.011), infertility rate (P = 0.005) and glucose (P = 0.045) and lower insulin-like growth factor-binding protein-1 (P = 0.012) than controls. The clinical, hormonal and metabolic characteristics did not differ significantly between cases without PCO and controls with the exception of infertility rate, which was significantly higher in the cases without PCO (26.4 vs. 10.0%; P = 0.009).

CONCLUSIONS

In a general population, women with symptoms of oligomenorrhoea and/or hirsutism more often have PCO than asymptomatic women. Levels of biochemical and clinical markers in symptomatic women with PCO differed from and were less favourable than those in symptomatic women without PCO or asymptomatic women, implying an increased risk for health.

Optimization of the anti-(human CD3) immunotoxin DT389-scFv(UCHT1) N-terminal sequence to yield a homogeneous protein

The production and regulatory approval processes for biopharmaceuticals require detailed characterization of potential products. Therapeutic proteins should preferably be homogeneous, although limited, reproducible, heterogeneity may be tolerated. A diphtheria toxin-based anti-(human CD3) immunotoxin, DT389-scFv(UCHT1), was expressed in Escherichia coli and purified following refolding [DT389 corresponds to amino acids 1-389 of diphtheria toxin, scFv is single-chain variable-region antibody fragment and UCHT1is an anti-(human CD3) monoclonal antibody]. Biochemical characterization of this molecule by MS and N-terminal sequencing by Edman degradation revealed that the protein was heterogeneous at the N-terminus, containing species both with (60%) and without (40%) the initiator methionine residue. In an attempt to generate an N-terminally homogeneous molecule, a panel of seven N-terminal variants was designed, based on the published specificity of bacterial methionine aminopeptidase. Following bacterial expression, partial purification and separation on SDS/PAGE, these proteins were subjected to N-terminal sequencing by Edman degradation. Three of the mutants yielded a 100% homogeneous amino acid sequence. By contrast, the original DT389-scFv(UCHT1) protein and four variant proteins yielded two sequences with varying ratios corresponding to species with and without methionine. The N-terminal sequences of the three homogeneous clones were MLADD and MLDD, where the methionine was completely retained, and SADD, where the methionine was completely removed. One of the homogeneous mutants (SADD) was expressed, refolded and purified and found to be equipotent with the parent immunotoxin. Thus, using a rational mutagenesis approach, three N-terminally homogeneous variants of DT389-scFv(UCHT1) have been identified, at least one of which is functionally indistinguishable from the parent immunotoxin. This approach is generally applicable to biopharmaceutical production and immunotoxin development in particular.

Nuclear magnetic resonance study of doxorubicin binding to cardiolipin containing magnetically oriented phospholipid bilayers

Doxorubicin (DOX) is a potent anthracycline cancer drug whose interaction with anionic membrane phospholipids, such as cardiolipin (CL), is thought to contribute to its cytotoxicity as well as induce cardiotoxic side effects. We have studied the interaction of DOX with a CL containing model membrane system using high resolution, oriented sample (31)P and (2)H NMR. The model membrane system is composed of a bilayer forming phospholipid and a detergent that breaks the extended bilayers into disc-shaped micelles (bicelles) that can orient in a magnetic field. The effects of DOX on the phospholipid bilayer were monitored using samples containing dimyristoylphosphatidylcholine (DMPC), selectively deuterated in either headgroup or acyl chain positions, and measuring the changes in (2)H quadrupolar splittings as DOX was added. Changes in quadrupolar splittings upon DOX addition provide evidence for interaction with both surface and buried sites within the membrane bilayer.

Influence of relative binding affinity on efficacy in a panel of anti-CD3 scFv immunotoxins

The in vitro cell killing potency of an immunotoxin reflects the aggregate of several independent biochemical properties. These include antigen binding affinity; internalization rate, intracellular processing and intrinsic toxin domain potency. This study examines the influence of antigen binding affinity on potency in various immunotoxin fusion proteins where target antigen binding is mediated by single chain antibody variable region fragments (scFv). Firstly, the relationship between affinity and potency was examined in a panel of four scFv immunotoxins generated from different anti-CD3 monoclonal antibodies fused to the 38 kDa fragment of Pseudomonas aeruginosa exotoxin A (PE38). Of these four scFv-PE38 immunotoxins, the one derived from the anti-CD3 monoclonal antibody UCHT1 has highest cell killing potency. Analysis of these four scFv-PE38 immunotoxins indicated a correlation between antigen binding affinity and immunotoxin potency in the cell killing assay with the exception of the scFvPE38 immunotoxin derived from the antibody BC3. However this scFv appeared to suffer a greater drop in affinity ( approximately 100x), relative to the parent Mab than did the other three scFvs used in this study (2-10x). Secondly, the scFv(UCHT1)-PE38 immunotoxin was then compared with a further panel of scFv(UCHT1)-derived immunotoxins including a divalent PE38 version and both monovalent and divalent Corynebacterium diphtheriae toxin (DT389) fusion proteins. When the scFv-UCHT1 domain was amino-terminally positioned relative to the toxin, as in the scFv(UCHT1)-PE38, an approximately 10-fold higher antigen-binding affinity was observed than with the C-terminal fusion, used in the DT389-scFv(UCHT1) molecule. Despite this lower antigen-binding activity, the DT389-scFv immunotoxin had a 60-fold higher potency in the T-cell-killing assay. Thirdly, a divalent form of the DT389-scFv construct, containing tandem scFv domains, had a 10-fold higher binding activity, which was exactly reflected in a 10-fold increase in potency. Therefore, when comparing immunotoxins in which scFvs from different antibodies are fused to the same toxin domain (DT or PE) a broad correlation appears to exist between binding affinity and immunotoxin potency. However, no correlation between affinity and potency appears to exist when different toxin domains are combined with the same scFv antibody domain.