Trajectory of adjustment difficulties following disaster: 10-year longitudinal cohort study

BACKGROUND

Although much is known about psychopathology such as post-traumatic stress disorder (PTSD) and depression following bushfire (also known as wildfire), little is known about prevalence, trajectory and impacts for those experiencing general adjustment difficulties following exposure to these now-common events.

AIMS

This was an exploratory analysis of a large cohort study that examined the prevalence, trajectory and risk factors of probable adjustment disorder over a 10-year period following bushfire exposure.

METHOD

The Beyond Bushfires study assessed individuals exposed to a large and deadly bushfire across three time points spanning 10 years. Self-report survey data from participants from areas with moderate and high levels of fire-affectedness were analysed: n = 802 participants at Wave 1 (3-4 years post-fires), n = 596 at Wave 2 (5 years post-fires) and n = 436 at Wave 3 (10 years post-fires). Surveys indexed fire-related experiences and post-fire stressors, and comprised the six-item Kessler Psychological Distress Scale (probable adjustment disorder index), four-item Posttraumatic Stress Disorder Checklist (probable fire-related PTSD) and nine-item Patient Health Questionnaire (probable major depressive episode).

RESULTS

Prevalence of probable adjustment disorder was 16% (Wave 1), 15% (Wave 2) and 19% (Wave 3). Probable adjustment disorder at 3-4 years post-fires predicted a five-fold increase in risk for escalating to severe psychiatric disorder (i.e. probable fire-related PTSD/major depressive episode) at 10 years post-fires, and was associated with post-fire income and relationship stressors.

CONCLUSIONS

Adjustment difficulties are prevalent post-disaster, many of which are maintained and exacerbated over time, resulting in increased risk for later disorder and adaptation difficulties. Psychosocial interventions supporting survivors with adjustment difficulties may prevent progression to more severe disorder.

Transcriptome analysis of blastoderms exposed to prolonged egg storage and short periods of incubation during egg storage

BACKGROUND

Cool temperature egg storage prior to incubation is a common practice in the broiler industry; however, prolonged egg storage causes increased embryonic mortality and decreased hatchability and growth in surviving chicks. Exposing eggs to short periods of incubation during egg storage (SPIDES) reduces the adverse consequences of prolonged storage. SPIDES increases blastodermal cell viability by reducing apoptosis, though the counteracting mechanisms are unclear. To define the impact of prolonged storage and SPIDES, transcriptome analysis compared gene expression from blastoderms isolated from eggs exposed to the following treatments: control (CR, stored at 17 °C for 4 days), prolonged storage (NSR, stored at 17 °C for 21 days), SPIDES (SR, stored at 17 °C for 21 days with SPIDES), and incubated control (C2, stored at 17 °C for 4 days followed by incubation to HH (Hamburger-Hamilton) stage 2, used as the ideal standard development) (n = 3/group). Data analysis was performed using the CLC Genomics Workbench platform. Functional annotation was performed using DAVID and QIAGEN Ingenuity Pathway Analysis.

RESULTS

In total, 4726 DEGs (differentially expressed genes) were identified across all experimental group comparisons (q < 0.05, FPKM> 20, |fold change| > 1.5). DEGs common across experimental comparisons were involved in cellular homeostasis and cytoskeletal protein binding. The NSR group exhibited activation of ubiquitination, apoptotic, and cell senescence processes. The SR group showed activation of cell viability, division, and metabolic processes. Through comparison analysis, cellular respiration, tRNA charging, cell cycle control, and HMBG1 signaling pathways were significantly impacted by treatment and potential regulatory roles for ribosomal protein L23a (RPL23A) and MYC proto-oncogene, BHLH transcription factor (MYC) were identified.

CONCLUSIONS

Prolonged egg storage (NSR) resulted in enriched cell stress and death pathways; while SPIDES (SR) resulted in enriched basic cell and anti-apoptotic pathways. New insights into DNA repair mechanisms, RNA processing, shifts in metabolism, and chromatin dynamics in relation to egg storage treatment were obtained through this study. Although egg storage protocols have been examined through targeted gene expression approaches, this study provided a global view of the extensive molecular networks affected by prolonged storage and SPIDES and helped to identify potential upstream regulators for future experiments to optimize egg storage parameters.

Transcriptome analysis of inseminated sperm storage tubules throughout the duration of fertility in the domestic turkey, Meleagris gallopavo

Sperm storage tubules (SST) are specialized invaginations of the oviductal epithelium that permit avian species to store spermatozoa for extended periods of time, without compromising sperm fertilization capacity. The molecular and physiological mechanisms behind sperm storage tubule differentiation, sperm protection, and regression remain largely unknown, but most likely have potential implications for substantially improving hen fertility, sperm storage, and semen cryopreservation in commercial poultry species. RNA sequencing was performed on sperm storage tubules isolated from the epithelium of the uterovaginal junction (UVJ) from hens at d 1, 7, 30, 60, and 90 postinsemination (n = 4 per timepoint). Read mapping and differential expression analysis were performed using CLC Genomics Workbench. A total of 2,340 differentially expressed genes were subjected to pathway analysis through Ingenuity Pathway Analysis (IPA). Through functional annotation of differentially expressed genes during early, peak, and late egg production, novel insights regarding the role of innate and acquired immune response to sperm, lipid synthesis and transfer, steroid hormone signalling, cytoskeletal reorganization, and regulation of ion homeostasis in SST were obtained. Additionally, potential pathways were identified that could be involved with suppressing sperm motility while sperm reside within the SST. Upstream analysis identified potential regulatory roles for 18 upstream regulators that could modulate sperm storage tubule function, including suppression of sperm motility. Understanding sperm storage tubule function throughout the laying cycle, especially with regards to sperm preservation may allow for the development of industry-based protocols for semen storage and cryopreservation that mimic the sperm preservation capabilities of SST and improve fertility.

Parental subjective assessment of gait limitations: Comparison with objective gait variables

BACKGROUND

Subjective assessment is an important part of clinical examination providing quality insights into impairments of body structure and functions. Research into the associations between parental perceptions of gait in children with cerebral palsy (CP) and objective clinical gait measures is limited.

RESEARCH QUESTION

What are the parental perceived gait limitations in children with CP and are these perceptions associated with objective clinical gait analysis?

METHODS

Parent questionnaires were retrospectively analysed for children with CP who attended our gait analysis laboratory over a 24-month period. Perceived walking limitations caused by pain, weakness, lack of endurance, mental ability, safety concerns, and balance were recorded on a 5-point Likert scale. Normalised gait speed, normalised step length and the Gait Deviation Index (GDI) were calculated. Differences between responses were assessed using Chi-squared tests with Dunn's post hoc test with Bonferroni adjustment. Spearman's rank correlations were performed to determine the relationship between responses and gait parameters.

RESULTS

Data from 251 participants were included, mean age 9 ± 3.4 years, Gross Motor Function Classification System (GMFCS) level I = 158, II = 64 and III = 29. Balance was perceived to limit walking to the greatest extent, followed by weakness, lack of endurance, safety concerns, pain and mental ability. This rank was consistent across GMFCS levels I, II and III. Perceived balance limitations showed the strongest correlations with objective gait variables, GDI (r = -0.31 p = 0.000), normalised step length (r = -0.30 p = 0.0000) and normalised gait speed (r = -0.24 p = 0.0001).

SIGNIFICANCE

Subjective gait perceptions provide a valuable indication of gait function but are weakly associated with objective clinical gait analysis. Outcome measures that are sensitive to changes in balance may be more responsive to parental concerns and help to satisfy their goals and expectations.

Hierarchies of affectedness after disasters

Disasters result in a range of impacts that significantly disrupt the health and wellbeing of those affected. After disasters, a hierarchy of affectedness may be explicitly or implicitly developed, where those affected are compared to each other, and to people affected by disasters in other locations. When an individual's sense of place is so significantly disrupted, these hierarchies are critical to improving the understanding of recovery trajectories, including mental health and well-being outcomes. These hierarchies have practical implications that influence the health outcomes of those affected, including eligibility for disaster aid, support services, and the way that people affected by disasters relate to others in their community. This paper expands the 'hierarchy of affectedness' concept coined by Andersen (2013) using findings from a qualitative study in Australia and New Zealand. Using a letter writing research method, twenty people who had been impacted by a range of disasters in different locations described what they considered helpful and unhelpful in the recovery. One emergent finding in this study was that hierarchies of affectedness are negotiated between impacted individuals, others affected in the same community, and outsiders. These hierarchies served as a helpful sense-making tool for some people impacted by disasters, while causing considerable secondary stress for others. Based on these findings, we offer an expansion to Andersen's existing model of hierarchies of affectedness in post-disaster settings.

Standardized Assessment of Global activities in the Elderly scale in adult cardiac surgery patients

BACKGROUND

Different instruments have been used to assess ability to perform everyday functional activities, such as activities of daily living (ADL) and instrumental activities of daily living (IADL). No measures of functional activity have been validated in cardiac surgery. We assessed the reliability and validity of the Standardized Assessment of Global activities in the Elderly (SAGE) scale.

METHODS

We undertook an observational sub-study of VISION Cardiac Surgery. Patients were assessed post-discharge after cardiac surgery using SAGE and comparator measures to determine convergent validity. A blinded independent assessor administered SAGE by phone within 7 days to determine test-retest reliability. We sought to demonstrate a correlation of ≥0.5 between SAGE and each corresponding measure. We also sought to define the SAGE score corresponding to severe functional disability, defined using the World Health Organisation Disability Assessment Schedule (WHODAS).

RESULTS

There were 152 patients included. Inter-rater reliability was excellent (intra-class correlation coefficient=0.99; 95% confidence interval [CI], 0.98-0.99). Convergent validity was evident, ranging from adequate for the overall SAGE score (0.54; 95% CI, 0.42-0.65) to very good for the SAGE mobility sub-score (0.80; 95% CI, 0.73-0.85). SAGE was initially poorly correlated with the IADL index (-0.24) but increased to -0.60 after post-hoc adjustment of SAGE scoring. A SAGE score ≥7 was associated with severe functional disability and occurred in 42/152 (27.6%) of patients.

CONCLUSION

These results demonstrate the reliability and validity of the SAGE scale as a measure of global function in patients discharged home after cardiac surgery.

CLINICAL TRIAL REGISTRATION

NCT01842568.

Vitamin K antagonists versus direct oral anticoagulants after cardiac surgery: a 31-country cohort study

Background

About 10% of patients undergoing cardiac surgery have a history of atrial fibrillation (AF). Among these patients, uncertainty exists regarding the safest and most effective oral anticoagulant (OAC) during the postoperative period.

Purpose

To evaluate practice patterns regarding OAC early after cardiac surgery in patients with a preoperative history of AF and to compare the safety and effectiveness of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs).

Methods

We conducted a nested cohort study within the Left Atrial Appendage Occlusion Study (LAAOS) III (NCT01561651). LAAOS III included patients with AF undergoing cardiac surgery with a CHA2DS2-VASC ≥2. In this substudy, we examined patients without end-stage renal dysfunction (eGFR &gt;30 mL/min/1.73m2) who were discharged on OAC. We evaluated bleeding and thromboembolism within 90 days postoperatively using logistic regression adjusting for CHA2DS2-VASC score.

Results

Recruitment started in 2012 and completed in 2018 in 113 centres in 31 countries. Of the 4811 patients enrolled in LAAOS III, 3725 (77%) were included in this substudy. Preoperatively, 58% of patients received OAC: 56% DOACs and 44% VKAs. At hospital discharge 23% received DOACs and 77% VKAs; 55% of patients on a DOAC at baseline were switched to a VKA while 5% of patients on a VKA were switched to a DOAC. Patients discharged on a DOAC were older, had a higher CHA2DS2-VASC, and were more likely to be male. Patients having undergone an isolated coronary bypass procedure were more likely prescribed DOACs than VKAs (41% vs 23%, p&lt;0.001) whereas isolated non-mechanical valve patients were more likely to be prescribed VKAs (43% vs 28%, p&lt;0.001). Switching from a DOAC to a VKA postoperatively occurred in 42% of patients In Australia/New Zealand, 49% in Europe, and 63% in North America. Major bleeding between 48 hours postoperatively and 30 days occurred in 1.5% in the DOAC group and 1.3% in the VKA group (aOR 1.14, 95% CI 0.60–2.15, p=0.69) while between 48 hours and 90 days, it occurred in 1.8% of patients in both groups (aOR 0.97, 95% CI, 0.54–1.17, p=0.91). Cardiac tamponade, the composite of stroke and systemic arterial embolism, and the composite of stroke, systemic arterial embolism and death did not differ significantly at 30 and 90 days between the DOAC and VKA groups.

Conclusions

VKAs was the dominant OAC used early after cardiac surgery, but postoperative OAC practices varied by region. After adjustment for CHA2DS2-VASC score, the early postoperative incidence of major bleeding and of the composite of stroke and systemic arterial embolism did not differ significantly when DOACs were compared with VKAs.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): CIHR, Heart and Stroke Foundation

Rethinking the interplay between affluence and vulnerability to aid climate change adaptive capacity

Affluence and vulnerability are often seen as opposite sides of a coin-with affluence generally understood as reducing forms of vulnerability through increased resilience and adaptive capacity. However, in the context of climate change and an increase in associated hazards and disasters, we suggest the need to re-examine this dynamic relationship-a complex association we define here as the Affluence-Vulnerability Interface (AVI). We review research in different national contexts to show how a more nuanced understanding of the AVI can (a) problematize the notion that increasing material affluence necessarily has a mitigating influence on social vulnerability, (b) extend our analysis of social vulnerability beyond low-income regions to include affluent contexts and (c) improve our understanding of how psychosocial characteristics influence people's vulnerability. Finally, we briefly outline three methodological approaches that we believe will assist future engagement with the AVI.

Crouch gait or flexed-knee gait in cerebral palsy: Is there a difference? A systematic review

BACKGROUND

Crouch or flexed-knee gait is one of the most common pathological gait patterns in cerebral palsy (CP). Differences exist in definitions used; the degree of knee flexion, inclusion of hip or ankle position, and timing in the gait cycle. This ambiguity may be responsible for variations in prevalence rates and difficulty comparing data across studies.

RESEARCH QUESTION

What are the kinematic parameters used to define crouch or flexed-knee gait in CP gait? A secondary aim was to examine the quality of data reporting, focusing on the sample characteristics, inclusion/exclusion criteria and the choice of limb included for analysis.

METHODS

Articles included in this review reported on a specified cohort of adults or children with crouch or flexed-knee gait assessed with 3-dimensional gait analysis. A customised data extraction and quality assessment table was designed specific to the research question.

RESULTS

The majority (75 %) of included studies used the term crouch gait. Where the pattern was defined, 80 % of crouch papers and 94 % of flexed-knee gait papers based this solely on knee position. Kinematic parameters were clearly defined when they provided objective values of knee flexion, supported this with rationale and provided a reference point in the gait cycle. Only 22 % of crouch papers and 19 % of flexed-knee gait papers provided this information. The majority of studies (67 % crouch; 90 % flexed-knee) specified which limb(s) were included for analysis with the majority including both limbs. Objective values of knee flexion ranged from 8 o to 30 o.

SIGNIFICANCE

This review highlights that crouch and flexed knee are synonymous and ambiguity exists in the kinematic definition making it difficult to make compare data amongst study cohorts. Future research should provide detailed definitions including the threshold value of knee flexion, how it was derived, the timing in the gait cycle and the limb(s) included in analysis.

Impacts of dietary calcium, phytate, and phytase on inositol hexakisphosphate degradation and inositol phosphate release in different segments of digestive tract of broilers

A total of 720 straight-run Heritage 56 M × fast feathering Cobb 500F broiler chickens was fed from 11 to 13 d of age to determine the impacts of dietary calcium (Ca), phytate phosphorus (PP), and phytase concentrations on inositol phosphate (IP3-6) profile in different digestive tract (GI) segments. The experiment was a 2 × 2 × 3 randomized block design with 2 Ca (0.7 and 1.0%) and 2 PP (0.23 and 0.34%) concentrations and 3 doses of Buttiauxella sp. phytase (0, 500, and 1,000 FTU/kg). The experiment was replicated in time (block) with 3 replicates per treatment (Trt) of 10 birds per block. Concentrations of IP3-6 in the crop, proventriculus (Prov) plus (+) gizzard (Giz), and distal ileum, as well as the ileal IP6 and P disappearance were determined at 13 d of age. The detrimental impact of Ca on IP6 and P disappearance was observed only in the ileum, where 11% reduction in both IP6 and P disappearance was seen when Ca increased from 0.7 to 1.0% (P < 0.05). Higher IP5 and IP6 concentrations were seen in both the crop and Prov+Giz at 0.34% PP as compared to birds fed to 0.23% PP diets, regardless of Ca or phytase (P < 0.05), whereas IP3 and IP4 concentrations were not affected by PP (P > 0.05). Inclusion of phytase, at both 500 and 1,000 FTU/kg, resulted in lower IP6 and the accumulation of lower IP ester (IP3-5) concentrations in all GI segments (P < 0.05). Improved IP6 and P disappearance was seen as a result of phytase inclusion, despite the degree of improvement affected by PP (P < 0.05). On average, 5.5 and 6.7 times improvement in IP6 was observed with 500 and 1,000 FTU phytase/kg inclusion, respectively, resulting in 41 and 64% greater P digestibility, respectively. In conclusion, phytase can effectively degrade IP6 to lower esters and increase P utilization. However, the efficacy of phytase can be affected by diet Ca and PP concentrations.

Impacts of dietary calcium, phytate, and nonphytate phosphorus concentrations in the presence or absence of phytase on inositol hexakisphosphate (IP6) degradation in different segments of broilers digestive tract

A total of 1,440 straight-run Heritage 56M × fast-feathering Cobb 500F broiler birds were fed from 11 to 13 d of age to determine the impacts of calcium (Ca), phytate phosphorus (PP), nonphytate P (NPP) and phytase concentrations on the myo-inositol hexakisphosphate (IP6) flow through the different parts of gastrointestinal tract (GIT). The experiment was a 2×2×2×3 randomized block design with 2 Ca (0.7 and 1.0%), 2 PP (0.23 and 0.34%), 2 nPP (0.28 and 0.45%) and 3 phytase (0-, 500-, and 1,000-phytase unit (FTU)/kg) concentrations. The experiment was replicated twice (block) with 3 replicates per treatment (TRT) of 10 birds per block. Concentration of IP6 in crop, proventriculus (PROV) plus (+) gizzard (GIZ) and distal ileum digesta as well as the ileal IP6 disappearance was determined at 13 d of age. In crop, higher IP6 concentration was seen with increased Ca (P < 0.05). Despite the interaction between PP and phytase, higher dietary PP led to greater IP6 concentration (P < 0.05). Similar main effects of PP and phytase were also seen in Prov+Giz and ileum (P < 0.05) without interactions. Interaction between Ca and nPP on IP6 concentration was seen in Prov+Giz (P < 0.05). Decreased ileal IP6 disappearance was found at higher Ca (62.3% at 0.7% Ca vs. 57.5% at 1.0% Ca; P < 0.05). In general, adding phytase improved IP6 degradation but the degree of impact was dependent on nPP and PP (P < 0.05). In conclusion, phytase inclusion significantly reduced IP6 concentration and IP6 disappearance in distal ileum regardless of GIT segments or diet composition, but impacts of dietary Ca, nPP, and PP differed depending on GIT segment examined.

Heart rate passivity of cerebral tissue oxygenation is associated with predictors of poor outcome in preterm infants

AIM

Near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD) allow non-invasive assessment of cerebral haemodynamics. We assessed cerebrovascular reactivity in preterm infants by investigating the relationship between NIRS- and TCD-derived indices and correlating them with severity of clinical illness.

METHODS

We recorded the NIRS-derived cerebral tissue oxygenation index (TOI) and TCD-derived flow velocity (Fv), along with other physiological variables. Moving correlation coefficients between measurements of cerebral perfusion (TOI, Fv) and heart rate were calculated. We presumed that positivity of these correlation coefficients - tissue oxygenation heart rate reactivity index (TOHRx) and flow velocity heart rate reactivity index (FvHRx) - would indicate a direct relationship between cerebral perfusion and cardiac output representing impaired cerebrovascular autoregulation.

RESULTS

We studied 31 preterm infants at a median age of 2 days, born at a median gestational age of 26 + 1 weeks. TOHRx was significantly correlated with gestational age (R = -0.57, p = 0.007), birth weight (R = -0.58, p = 0.006) and the Clinical Risk Index for Babies II (R = 0.55, p = 0.0014). TOHRx and FvHRx were significantly correlated (R = 0.39, p = 0.028).

CONCLUSION

Heart rate has a key influence on cerebral haemodynamics in preterm infants, and TOHRx may be of diagnostic value in identifying impaired cerebrovascular reactivity leading to adverse clinical outcome.

Rationale and design of the Left Atrial Appendage Occlusion Study (LAAOS) III

BACKGROUND

Occlusion of the left atrial appendage (LAA) is a promising approach to stroke prevention in atrial fibrillation (AF). However, evidence of its efficacy and safety to date is lacking. We herein describe the rationale and design of a definitive LAA occlusion trial in cardiac surgical patients with AF.

METHODS

We plan to randomize 4,700 patients with AF in whom on-pump cardiac surgical procedure is planned to undergo LAA occlusion or no LAA occlusion. The primary outcome is the first occurrence of stroke or systemic arterial embolism over a mean follow-up of four years. Other outcomes include total mortality, operative safety outcomes (chest tube output in the first post-operative 24 hours, rate of post-operative re-exploration for bleeding in the first 48 hours post-surgery and 30-day mortality), re-hospitalization for heart failure, major bleed, and myocardial infarction.

RESULTS

Left Atrial Appendage Occlusion Study (LAAOS) III is funded in a vanguard phase by the Canadian Institutes for Health Research (CIHR), the Canadian Network and Centre for Trials Internationally, and the McMaster University Surgical Associates. As of September 9, 2013, 162 patients have been recruited into the study.

CONCLUSIONS

LAAOS III will be the largest trial to explore the efficacy of LAA occlusion for stroke prevention. Its results will lead to a better understanding of stroke in AF and the safety and efficacy of surgical LAA occlusion.

Risks for impaired cerebral autoregulation during cardiopulmonary bypass and postoperative stroke

BACKGROUND

Impaired cerebral autoregulation may predispose patients to cerebral hypoperfusion during cardiopulmonary bypass (CPB). The purpose of this study was to identify risk factors for impaired autoregulation during coronary artery bypass graft, valve surgery with CPB, or both and to evaluate whether near-infrared spectroscopy (NIRS) autoregulation monitoring could be used to identify this condition.

METHODS

Two hundred and thirty-four patients were monitored with transcranial Doppler and NIRS. A continuous, moving Pearson's correlation coefficient was calculated between mean arterial pressure (MAP) and cerebral blood flow (CBF) velocity, and between MAP and NIRS data, to generate the mean velocity index (Mx) and cerebral oximetry index (COx), respectively. Functional autoregulation is indicated by an Mx and COx that approach zero (no correlation between CBF and MAP); impaired autoregulation is indicated by an Mx and COx approaching 1. Impaired autoregulation was defined as an Mx ≥0.40 at all MAPs during CPB.

RESULTS

Twenty per cent of patients demonstrated impaired autoregulation during CPB. Based on multivariate logistic regression analysis, time-averaged COx during CPB, male gender, Pa(CO(2)), CBF velocity, and preoperative aspirin use were independently associated with impaired CBF autoregulation. Perioperative stroke occurred in six of 47 (12.8%) patients with impaired autoregulation compared with five of 187 (2.7%) patients with preserved autoregulation (P=0.011).

CONCLUSIONS

Impaired CBF autoregulation occurs in 20% of patients during CPB. Patients with impaired autoregulation are more likely than those with functional autoregulation to have perioperative stroke. Non-invasive monitoring autoregulation may provide an accurate means to predict impaired autoregulation. Clinical trials registration. www.clinicaltrials.gov (NCT00769691).

Clinical training and competency guidelines for using robotic devices

With the increasing popularity of robotic devices in rehabilitation centers worldwide (e.g. Lokomat(®), ZeroG(®), ReoGo, InMotion 2.0, and Biodex System 4), there is a need for guidelines to ensure proper training and evaluation of therapists on the safe and effective use of these devices. Here, we present training tools and guidelines that were based on the recommendations of several device manufacturers and a user-group made up of clinicians and therapists. The training tools consist of a detailed user manual, clinical manual, hand-on training, video training and web based training tools. We also present procedures for evaluating user competency after they have completed detailed training. We believe that the comprehensive training and competency evaluation guidelines presented here will help ensure that rehabilitation robotic devices are used properly. This in turn will lead to more effective interventions and reduce the likelihood of injury.

Phase I dose escalation trial (ARQ 197–111) evaluating combination of selective c-Met inhibitor ARQ 197 and erlotinib

3549

Background: ARQ197 (A) is a selective, non-ATP competitive inhibitor of c-Met, a receptor tyrosine kinase implicated in tumor cell migration, invasion, and proliferation. Phase I data for ARQ 197 monotherapy is previously reported. Recent evidence suggests c-Met promotes resistance to EGFR-inhibition by driving ERBB3 (HER3)-dependent PI3K activation. Dual EGFR-Met inhibition is now proposed as a strategy for overcoming resistance to EGFR-inhibition. Methods: Patients (pts) were enrolled in a sequential-cohort dose-escalation trial seeking to define safety, tolerability, pharmacokinetics (PK), and preliminary anti-tumor activity of A in combination with 150 mg daily oral erlotinib (E). Oral A was administered at escalating doses of 120, 240, and 360 mg bid. Intra-patient dose escalation was allowed in the absence of dose-limiting toxicity (DLT) through 1 cycle of therapy (21 days). Results: 25 pts (10 F/15 M; mean 60.5 yrs) received EA combination with starting A dose of 120 (8 pts), 240 (4 pts), and 360 (13 pts) mg bid. PK data reveal linear kinetics through 360 bid and no evidence of drug-drug interaction. Adverse events (AEs) considered related to combination therapy were reported in 13 (52%) of pts incl.sinus bradycardia (5 pts), fatigue (5 pts), rash (4 pts), itching (3 pts), and diarrhea (3 pts). 2 pts experienced related serious AEs incl. neutropenia (360 bid) and sinus bradycardia (240 bid). 1 death occurring on-study was considered unrelated to study drug. 9/10 evaluable pts demonstrated disease stabilization (SD) as their best RECIST response (5.9–27.1+ wks). Tumor regressions (2.3%-19.4%) were observed in 4/10 evaluable pts. Of note, 3/3 evaluable pts with NSCLC achieved SD for durations (14–32 wks) exceeding median PFS in BR.21 (9.7 wks). Conclusions: Continuous therapy with EA combination appears well tolerated and without drug-drug interaction. While no formal MTD was identified, a phase 2 combination dose (R2PD) of 360 mg bid A + 150 mg daily E is recommended. This RP2D is currently being investigated in an ongoing randomized trial comparing EA to E monotherapy in 2nd/3rd line NSCLC.

[Table: see text]

Persistent nodules at injection sites (aluminium granuloma) -- clinicopathological study of 14 cases with a diverse range of histological reaction patterns

AIMS

To assess and document the spectrum of histological appearances of persistent swellings which occur at injection sites following vaccination or allergen desensitization.

METHODS AND RESULTS

Fourteen cases were studied. Four overlapping histological reaction patterns were evident. Ten cases showed at least focal fibrosis, fat necrosis and a mixed inflammatory cell infiltrate mainly in the subcutis, giving rise to the features of a non-specific septal and lobular panniculitis. The appearance of three cases, in addition to the non-specific panniculitis pattern, also included prominent lymphoid follicles with germinal centres and a prominent perifollicular infiltrate resembling a lymphoma (pseudolymphoma pattern). A single case mimicked lupus profundus, with a perivascular and periadnexal infiltrate in the dermis and hyaline fat necrosis. Three cases showed a predominantly palisaded histiocytic infiltrate surrounding eosinophilic necrobiosis, in a pattern closely resembling deep granuloma annulare or rheumatoid nodule. The remaining case partly showed this appearance, but in combination with panniculitis, thus demonstrating an overlap of patterns. A common feature in all 14 cases was the focal presence of histiocytes with abundant violaceous granular cytoplasm. These were shown to contain aluminium on energy dispersive X-ray microanalysis.

CONCLUSION

Persistent swellings at injections sites show a variety of overlapping patterns, which mimic other conditions. Identification of characteristic histiocytes with violaceous granular cytoplasm is the key distinctive feature allowing the correct diagnosis to be reached.

Long-term outcome after laparoscopic and open surgery for rectal prolapse: a case-control study

BACKGROUND

Laparoscopic repair (LR) of rectal prolapse is potentially associated with earlier recovery and lower perioperative morbidity, as compared with open transabdominal repair (OR). Data on the long-term recurrence rate and functional outcome are limited.

METHODS

Perioperative data on rectal prolapse in relation to all LRs performed between December 1991 and April 2004 were prospectively collected. The LR patients were matched by age, gender, and procedure type with OR patients who underwent surgery during the same period. Patients with previous complex abdominal surgery or a body mass index exceeding 40 were excluded from the study. Data on recurrence rate, bowel habits, continence, and satisfaction scores were collected using a telephone survey.

RESULTS

A total of 111 patients (age, 56.8 +/- 18.1 years; female, 87%) underwent attempted LR. An operative complication deferred repair in two cases. Among the 111 patients, 42 had posterior mesh fixation, and 67 had sutured rectopexy (32 patients with sigmoid colectomy for constipation). Eight patients (7.2%) had conversion to laparotomy. Matching was established for 86 patients. The LR patients had a shorter hospital stay (mean, 3.9 vs 6.0 days; p < 0.0001). The 30-day reoperation and readmission rates were similar for the two groups. The rates for recurrence requiring surgery were 9.3% for LR and 4.7% for OR (p = 0.39) during a mean follow-up period of 59 months. An additional seven patients in each group reported possible recurrence by telephone. Postoperatively, 35% of the LR patients and 53% of the OR patients experienced constipation (p = 0.09). Constipation was improved in 74% of the LR patients and 54% of the OR patients, and worsened, respectively, in 3% and 17% (p = 0.037). The postoperative incontinence rates were 30% for LR and 33% for OR (p = 0.83). Continence was improved in 48% of the LR patients and 35% of the OR patients, and worsened, respectively, in 9% and 18% (p = 0.22). The mean satisfaction rates for surgery (on a scale of 0 to 10) were 7.3 for the LR patients and 8.1 for the OR patients (p = 0.17).

CONCLUSIONS

The hospital stay is shorter for LR than for OR. Both functional results and recurrent full-thickness rectal prolapse were similar for LR and OR during a mean follow-up period of 5 years.

Severe generalized argyria secondary to ingestion of colloidal silver protein

Argyria is a rare cause of cutaneous discolouration caused by silver deposition. We report a case of dramatic and diffuse argyria secondary to ingestion of colloidal silver protein over a 1-year period. Stained electron microscopy with spectral analysis was used to confirm the clinical diagnosis. Silver-protein complexes are deposited in the skin and reduced to inert silver salts by sunlight in a process similar to that harnessed in photography. Our patient had obtained the silver for consumption via mail order. It had been advertised as a cure for a variety of diseases. Colloidal silver protein is commercially available as a 'food supplement', hence circumventing the strict controls placed on medicines.

CD40 employs p38 MAP kinase in IgE isotype switching

IgE switching requires the prior induction of C epsilon germline transcripts which is mediated by the concerted binding of STAT-6 and NF kappa B to the C epsilon promoter. These transcription factors are regulated by IL-4 and CD40, respectively. However the latter can effect other signaling pathways and the present study explores the role of p38 MAPK in induction of C epsilon germline transcripts. CD40 and IL-4, both alone and in synergy, were initially shown to activate the C epsilon promoter in a B cell lymphoma cell line. Under the same conditions CD40 caused activation of p38 MAPK, whereas IL-4 was ineffective. The p38 MAPK inhibitor, SB203580, and a dominant negative form of p38 MAPK decreased the CD40 activation of the C epsilon promoter by reducing the ability of CD40 to increase the transactivation potential of NF kappa B. This study suggests that p38 MAPK is crucially important in mediating CD40 activation of NF kappa B which acts to induce C epsilon germline transcripts, ultimately facilitating IgE switching.

Understanding birthing mode decision making using artificial neural networks

BACKGROUND

This study examined obstetricians' decisions to perform or not to perform cesarean sections. The aim was to determine whether an artificial neural network could be constructed to accurately and reliably predict the birthing mode decisions of expert clinicians and to elucidate which factors were most important in deciding the birth mode.

METHODS

Mothers with singleton, live births who were privately insured, nonclinic, non-Medicaid patients at a major tertiary care private hospital were included in the study (N = 1508). These mothers were patients of 2 physician groups: a 7-obstetrician multispecialtygroup practice and a physician group of 79 independently practicing obstetricians affiliated with the same hospital. A feedforward, multilayer artificial neural network (ANN) was developed and trained. It was then tested and optimized until the most parsimonious network was identified that retained a similar level of predictive power and classification accuracy. The performance of this network was further optimized using the methods of receiver operating characteristic (ROC) analysis and information theory to find the cutoff that maximized the information gain. The performance of the final ANN at this cutoff was measured using sensitivity, specificity, classification accuracy, area under the ROC curve, and maximum information gain.

RESULTS

The final neural network had excellent predictive accuracy for the birthing mode (classification accuracy = 83.5%; area under the ROC curve = 0.924; maximum information = 40.4% of a perfect diagnostic test).

CONCLUSION

This study demonstrated that a properly optimized ANN is able to accurately predict the birthing mode decisions of expert clinicians. In addition to previously identified clinical factors (cephalopelvic disproportion, maternal medical condition necessitating a cesarean section, arrest of labor, malpresentation of the baby, fetal distress, andfailed induction), nonclinical factors such as the mothers' views on birthing mode were also found to be important in determining the birthing mode.

Rape and physical violence: comparison of assault characteristics in older and younger adults in the National Women's Study

This study compared characteristics of recently occurring assaults against younger adults (age 18-34 years) with those of distant-past assaults against older adults (age 55-89 years) when they were younger. Responses of a subset of participants in the National Women's Study were the source of data for this study. With the exception of perceived life threat during assault (more prevalent in younger women), assault characteristics did not vary greatly by age in terms of proportions reporting that they had seen the perpetrator before; the event was one in a series; they or the perpetrator were under the influence of a substance; they actually experienced injury; and they reported the assault to authorities. Consistent with previous research, younger women reported greater prevalences of assault than older women.

Laparoscopic total colectomy for acute colitis: a case-control study

INTRODUCTION

There are no previous comparative studies of total abdominal colectomy by laparoscopic methods in ulcerative colitis and Crohn's disease patients requiring urgent colectomy. This study aimed to determine the safety and efficacy of laparoscopic colectomy in these patients compared with those undergoing conventional urgent colectomy.

METHODS

Patients undergoing laparoscopic total colectomy for acute colitis were identified in a prospective registry. All patients underwent a total colectomy with creation of an end ileostomy and buried mucous fistula. No patient had fulminant disease (tachycardia, fever, marked leukocytosis, peritonitis), but all were failing to respond to medical treatment. Patients undergoing conventional total colectomy were matched for age, gender, body mass index, diagnosis, disease severity, and operative period. Median values (range) are listed.

RESULTS

From 1997 to 1999, there were 19 laparoscopic and 29 matched conventional patients. There were no inadvertent colotomies or conversions in the laparoscopic group. Although there was no difference in operative blood loss in the laparoscopic group (100 (range, 50-700) ml) when compared with the conventional group (150 (range, 50-500) ml), the operative times were significantly longer in the laparoscopic group (210 (range, 150-270) vs. 120 (range, 60-180) minutes, P < 0.001). Bowel function returned more quickly in the laparoscopic group (1 (range, 1-3) vs. 2 (range, 1-4) days; P = 0.003) and the length of stay was shorter (4 (range, 3-13) vs. 6 (range, 4-24) days; P = 0.04). Complications occurred in three (16 percent) laparoscopic patients (2 wound infection and 1 ileus) and in seven (24 percent) conventional patients (3 wound infection, 3 deep venous thrombosis, 1 upper gastrointestinal bleed).

CONCLUSIONS

Laparoscopic total colectomy is feasible and safe in patients with acute nonfulminant colitis and may lead to a faster recovery than conventional resection.

Generation and refinement of peptide mimetic ligands for paratope-specific purification of monoclonal antibodies

Paratope-specific purification of antibodies has distinct advantages over conventional methods of antibody purification with respect to its capacity to isolate product of high purity and immunoreactivity. The present report addresses the problems of identifying peptide ligands for the purification of antibodies reactive with nonprotein antigens. Using an anti-steroid antibody as the model, a lead sequence that bound antibody was identified from a peptide phage display library. The minimum binding unit in this sequence was deduced using a series of truncated peptides synthesized on the heads of polyethylene pins. Replacement Net analysis of the minimum binding unit identified peptides with increased affinity for the antibody. The affinity-matured peptide mimotope bound antibody in solution. By molecular modeling the peptide was superimposable onto estrone-3-glucuronide localized in the crystal structure of the antibody binding pocket. In order to resolve problems of presentation posed by the reversal of orientation of the peptide on the affinity matrix compared with the pins, the mimotope peptide was synthesized in reverse sequence using d-amino acids. The resulting affinity matrix was effective for the purification of antibody. Eluted product demonstrated molecular homogeneity and high immunoreactivity. It is concluded that the combination of biological and chemical library techniques described provides a method for the generation and affinity maturation of mimotopes for antibodies against nonprotein antigens.

Self-reports of physical, sexual and emotional abuse in an alcoholism treatment sample

OBJECTIVE

There is a growing appreciation that emotional, physical and sexual abuse events are frequently part of the life histories of individuals in treatment for alcohol disorders. The present study examines reports of lifetime abuse in a clinical trial for treatment of alcohol dependency.

METHOD

Data were obtained from baseline assessments conducted with participants (N = 1,726; 1,307 men) entering Project MATCH, a multisite clinical trial conducted at nine geographically dispersed research sites. Differences on a broad range of participant characteristics were examined by gender and by reported abuse type.

RESULTS

More than half (59%) of the participants reported lifetime abuse. Women were more likely (77%) to report abuse than were men (54%). A lower proportion of men than women (6% vs 31%) reported experiencing both physical and sexual abuse. Gender differences were found on the majority of psychosocial measures. Comparisons of the psychosocial measures by abuse type generally indicated that participants without abuse histories had better functioning than did participants reporting abuse.

CONCLUSIONS

The high frequency of lifetime abuse in this geographically dispersed sample underscores the necessity for including assessment of emotional, physical and sexual abuse with alcoholism treatment seeking populations. Participants reporting such events may require other treatment in addition to that for alcohol dependency.

Summary report on the ISOBM TD-4 Workshop: analysis of 56 monoclonal antibodies against the MUC1 mucin. San Diego, Calif., November 17-23, 1996

Sixteen research groups participated in the ISOBM TD-4 Workshop in which the reactivity and specificity of 56 monoclonal antibodies against the MUC1 mucin was investigated using a diverse panel of target antigens and MUC1 mucin-related synthetic peptides and glycopeptides. The majority of antibodies (34/56) defined epitopes located within the 20-amino acid tandem repeat sequence of the MUC1 mucin protein core. Of the remaining 22 antibodies, there was evidence for the involvement of carbohydrate residues in the epitopes for 16 antibodies. There was no obvious relationship between the type of immunogen and the specificity of each antibody. Synthetic peptides and glycopeptides were analyzed for their reactivity with each antibody either by assay of direct binding (e.g. by ELISA or BiaCore) or by determining the capacity of synthetic ligands to inhibit antibody binding interactions. There was good concordance between the research groups in identifying antibodies reactive with peptide epitopes within the MUC1 protein core. Epitope mapping tests were performed using the Pepscan analysis for antibody reactivity against overlapping synthetic peptides, and results were largely consistent between research groups. The dominant feature of epitopes within the MUC1 protein core was the presence, in full or part, of the hydrophilic sequence of PDTRAPAP. Carbohydrate epitopes were less easily characterized and the most useful reagents in this respect were defined oligosaccharides, rather than purified mucin preparations enriched in particular carbohydrate moieties. It was evident that carbohydrate residues were involved in many epitopes, by regulating epitope accessibility or masking determinants, or by stabilizing preferred conformations of peptide epitopes within the MUC1 protein core. Overall, the studies, highlight concordance between groups rather than exposing inconsistencies which gives added confidence to the results of analyses of the specificity of antimucin monoclonal antibodies.

Tumour-necrosis-factor-receptor-associated factor 6, NF-kappaB-inducing kinase and IkappaB kinases mediate IgE isotype switching in response to CD40

The process of IgE switching requires the prior transcription of the unrearranged Cepsilon gene, which leads to its recombination with the VDJ region. The activation of NF-kappaB by CD40 is a key process in facilitating this transcription by promoting the activation of the Cepsilon promoter. The present study explores the uncharacterized signalling pathways employed by CD40 in activating NF-kappaB by the overexpression of genes encoding wild-type and dominant-negative forms of the signalling components tumour-necrosis-factor-receptor-associated factor 6 (TRAF-6), NF-kappaB-inducing kinase (NIK), IkappaB kinase (IKK)-1 and IKK-2 in the BJAB B-cell line. The overexpression of TRAF-6 or NIK was sufficient to activate NF-kappaB and the Cepsilon promoter, whereas their dominant-negative counterparts decreased the ability of CD40 to activate NF-kappaB and the Cepsilon promoter. The overexpression of wild-type IKK-1 or IKK-2 seemed to cause toxic effects on the cells, whereas the dominant-negative forms were selective in their blockade of NF-kappaB and the Cepsilon promoter. These results suggest that CD40 employs TRAF-6, which presumably recruits NIK, which in turn employs IKK-1/IKK-2 to activate NF-kappaB and the Cepsilon promoter, the prologue to IgE switching. Thus the findings define a crucially important pathway in the generation of allergic states.

Rapid polarization of Th2 cells during induction of antigen-specific IgE antibodies in vitro

BACKGROUND

Type 2 T-helper cells (Th2) are involved in the regulation of the humoral immune response against antigens and allergens and directly affect which isotype will be produced. The mechanism that regulates antigen-specific IgE secretion and immune deviation is still not known.

OBJECTIVES

To delineate mechanisms behind antigen-specific IgE secretion we have used in vitro immunization and focused on T-cell phenotype and the activation status of the transcription factor NFkappaB.

METHODS

Peripheral blood lymphocytes (PBMC) from seronegative donors were immunized in vitro with a peptide consisting of both a T-cell and a B-cell epitope.

RESULTS

Antigen-specific IgE antibodies could be detected after a primary immunization, during which T-helper cells secreted type 2 cytokines. Specific IgE was also detected in the secondary immunization, but due to a rapid polarization from Th2 to Th1 phenotype, exogenous IL-4 was required for the specific IgE secretion. Analysis of NFkappaB activation in B and T cells during primary and secondary immunization showed that NFkappaB could be detected in both B and T cells during primary immunization, but was dependent on exogenous IL-4 in the secondary immunization.

CONCLUSION

This is the first evidence of antigen-specific IgE induction in vitro using naive B cells, demonstrating the involvement of T-helper cell phenotype and NFkappaB and demonstrates the usefulness of in vitro cultures to study the effect of antigens on human immunocytes.

Current issues in the identification and management of bipolar spectrum disorders in 'special populations'

Bipolar disorder is a common, lifelong condition that can present during childhood, adolescence, adulthood or later in life. It may occur alone but, more frequently, is complicated by comorbid psychiatric and medical disorders. As such, bipolar disorder presents in many different special populations, each of which warrants specific considerations of diagnosis, treatment and management. This review summarizes common issues concerning recognition of bipolar disorder, particularly in younger patients, discusses the prevalence and treatment of anxious disorder and addictive comorbidity, and considers bipolar disorder in the institutionalized and forensic populations. Treatment options and the supporting evidence are discussed.

Efficacy and safety of sertraline treatment of posttraumatic stress disorder: a randomized controlled trial

CONTEXT

Despite the high prevalence, chronicity, and associated comorbidity of posttraumatic stress disorder (PTSD) in the community, few placebo-controlled studies have evaluated the efficacy of pharmacotherapy for this disorder.

OBJECTIVE

To determine if treatment with sertraline hydrochloride effectively diminishes symptoms of PTSD of moderate to marked severity.

DESIGN

Twelve-week, double-blind, placebo-controlled trial preceded by a 2-week, single-blind placebo lead-in period, conducted between May 1996 and June 1997.

SETTING

Outpatient psychiatric clinics in 8 academic medical centers and 6 clinical research centers.

PATIENTS

A total of 187 outpatients with a Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition diagnosis of PTSD and a Clinician Administered PTSD Scale Part 2 (CAPS-2) minimum total severity score of at least 50 at baseline (mean age, 40 years; mean duration of illness, 12 years; 73% were women; and 61.5% experienced physical or sexual assault).

INTERVENTION

Patients were randomized to acute treatment with sertraline hydrochloride in flexible daily dosages of 50 to 200 mg/d, following 1 week at 25 mg/d (n=94); or placebo (n=93).

MAIN OUTCOME MEASURES

Baseline-to-end-point changes in CAPS-2 total severity score, Impact of Event Scale total score (IES), and Clinical Global Impression-Severity (CGI-S), and CGI-Improvement (CGI-I) ratings, compared by treatment vs placebo groups. Results Sertraline treatment yielded significantly greater improvement than placebo on 3 of the 4 primary outcome measures (mean change from baseline to end point for CAPS-2 total score, -33.0 vs -23.2 [P =.02], and for CGI-S, -1.2 vs -0.8 [P=.01]; mean CGI-I score at end point, 2.5 vs 3.0 [P=.02]), with the fourth measure, the IES total score, showing a trend toward significance (mean change from baseline to end point, -16.2 vs -12.1; P=.07). Using a conservative last-observation-carried-forward analysis, treatment with sertraline resulted in a responder rate of 53% at study end point compared with 32% for placebo (P=.008, with responder defined as >30% reduction from baseline in CAPS-2 total severity score and a CGI-I score of 1 [very much improved], or 2 [much improved]). Significant (P<.05) efficacy was evident for sertraline from week 2 on the CAPS-2 total severity score. Sertraline had significant efficacy vs placebo on the CAPS-2 PTSD symptom clusters of avoidance/numbing (P=.02) and increased arousal (P=.03) but not on reexperiencing/intrusion (P=.14). Sertraline was well tolerated, with insomnia the only adverse effect reported significantly more often than placebo (16.0% vs 4.3%; P=.01).

CONCLUSIONS

Our data suggest that sertraline is a safe, well-tolerated, and effective treatment for PTSD.

Neuroimaging variables related to development of Secondary Attention Deficit Hyperactivity Disorder after closed head injury in children and adolescents

OBJECTIVE

To characterize children who develop Secondary Attention Deficit Hyperactivity Disorder (S-ADHD) after severe and moderate closed head injury (CHI) according to neuroimaging variables.

METHOD

Ninety-nine children from 4-19 years who suffered severe and moderate CHI were prospectively followed for a year after injury. Premorbid psychiatric status was determined by administration to the parent of a structured psychiatric interview. This interview was readministered 1 year after injury to determine the presence of post-closed head injury S-ADHD. An MRI was performed 3 months after injury to define lesion locations and volumes.

RESULTS

A set of multiple logistic regression models determined that the odds of developing S-ADHD were 3.64 times higher among children with thalamus injury, and 3.15 times higher among children with basal ganglia injury. There was no significant difference in lesion volumes in any of the locations of interest between the group who developed S-ADHD and the group who did not develop S-ADHD.

CONCLUSION

The data support an association between S-ADHD and injury in either or both the thalamus and basal ganglia, but they do not definitively demonstrate whether injury in either structure has an effect on S-ADHD in the absence of injury in the other.

The effects of loop excision of the transformation zone on cervical length: implications for pregnancy

OBJECTIVE

This study was undertaken to determine whether previously described significant and quantitative cervical shortening caused by loop excision of the transformation zone persists after 3 months of healing.

STUDY DESIGN

A prospective study was designed in which 20 patients were enrolled. Each underwent transvaginal ultrasonography for determination of cervical length before the loop excision of the transformation zone and >/=3 months after the loop excision of the transformation zone. Simple regression analysis and the Student paired t test was performed to determine whether the length of the cervix had changed significantly between the measurements.

RESULTS

The mean cervical lengths as measured by transvaginal ultrasonography before and after loop excision of the transformation zone were 3.1 +/- 0.8 cm and 3.1 +/- 0.7 cm, respectively. The correlation between ultrasonographic measurements before and after loop excision of the transformation zone was r = 0.88 (P <.0001). A paired t test resulted in a P value of 1.0000, which indicates that the ultrasonographic measurement after loop excision of the transformation zone was not different from the ultrasonographic measurement before loop excision of the transformation zone. The mean difference between measurements was 0.0 +/- 0.4 cm.

CONCLUSION

After adequate healing time after loop excision of the transformation zone, the length of the cervix, as measured by transvaginal ultrasonography, does not appear to remain shortened.

Functionally different GPI proteins are organized in different domains on the neuronal surface

We have investigated the organization, on the plasma membrane and in detergent-insoluble membrane vesicles, of two neuronal glycosylphosphatidylinositol-anchored (GPI) proteins: Thy-1, a negative regulator of transmembrane signalling; and prion protein, whose rapid endocytosis and Cu(2+) binding suggest that it functions in metal ion uptake. Prion protein occurred on the neuronal surface at high density in domains, located primarily at the cell body, which were relatively soluble in detergent. Thy-1, although much more abundantly expressed on neurons, occurred at lower density over much of the surface of neurites (and in lower abundance at the cell body) in domains that were highly resistant to detergent solubilization. Detergent-insoluble membrane vesicles contained Thy-1 at a density similar to that on the neuronal surface. Vesicles containing each protein could be separated by immunoaffinity isolation; lectin binding showed that they were enriched in different glycoproteins. Our results demonstrate a structural diversity of the domains occupied by functionally different GPI proteins.

Structure/activity studies of the anti-MUC1 monoclonal antibody C595 and synthetic MUC1 mucin-core-related peptides and glycopeptides

MUC1 mucin is a large complex glycoprotein expressed on normal epithelial cells in humans and overexpressed and under or aberrantly glycosylated on many malignant cancer cells which consequently allows recognition of the protein core by antibodies. In order to understand how glycosylation may modulate or regulate antibody binding of mucin protein core epitopes, we have analyzed the antibody C595 (epitope RPAP) for its structure, stability, and its binding to a series of synthetic peptides and glycopeptides by a number of spectroscopic methods. Thermal and pH denaturation studies followed by changes in the CD spectrum of the antibody indicate critical involvement of specific residues to the stability of the antibody. Fluorescence binding studies indicate that alpha-N-acetylgalactosamine (GalNAc) glycosylation of a MUC1 mucin synthetic peptide TAPPAHGVT9SAPDTRPAPGS20T21APPA at threonine residues 9 and 21 and serine residue 20 enhanced the binding of antibody. The structural effects of GalNAc glycosylation on the conformation of the MUC1 peptide were studied. CD of the peptides and glycopeptides in a cryogenic mixture cooled to approximately -97 degrees C revealed that a left-handed polyproline II helix (PPII) is adopted by the peptides in solution, which appears to be further stabilized by addition of the GalNAc residues. Consistent with the PPII helical structure, which has no intra-amide hydrogen bonds, high-field NMR spectroscopy of the glycopeptide revealed no sequential dNN, medium-range, or long-range nuclear Overhauser effect (NOE) connectivities. These studies indicate that stabilization of the PPII helix by GalNAc glycosylation present the epitope of C595 antibody with a favorable conformation for binding. Furthermore, they illustrate that glycosylation of the MUC1 tumor marker protein with a simple O-linked saccharide expressed in many cancers, can enhance the binding of the clinically relevant C595 antibody.

Production and characterization of an anti-(MUC1 mucin) recombinant diabody

A recombinant diabody fragment based on the anti-MUC1 monoclonal antibody, C595 has been produced in a bacterial expression system. Substitution of a 7-amino-acid linker sequence (Gly6Ser) for the original single-chain (sc)Fv 15-amino-acid linker (Gly4-Ser)3, using polymerase-chain-reaction-based strategies, forces variable heavy (V(H)) and light (V(L)) domains to pair with complementary domains on neighbouring scFv molecules, forming a scFv dimer (diabody). This recombinant protein shows similar binding characteristics to the parental C595 monoclonal antibody. The ability to bind to MUC1 mucin on carcinoma cell surfaces will allow its potential as a diagnostic and therapeutic reagent of clinical utility to be investigated.