Measuring persistent somatic symptom related stigmatisation: Development of the Persistent Somatic Symptom Stigma scale for Healthcare Professionals (PSSS-HCP)

OBJECTIVE

Persistent somatic symptoms (PSS) describe recurrent or continuously occurring symptoms such as fatigue, dizziness, or pain that have persisted for at least several months. These include single symptoms such as chronic pain, combinations of symptoms, or functional disorders such as fibromyalgia or irritable bowel syndrome. While stigmatisation by healthcare professionals is regularly reported, there are limited measurement instruments demonstrating content validity. This study develops a new instrument to measure stigmatisation by healthcare professionals, the Persistent Somatic Symptom Stigma scale for Healthcare Professionals (PSSS-HCP).

METHODS

Development was an iterative process consisting of research team review, item generation and cognitive interviewing. We generated a longlist of 60 items from previous reviews and qualitative research. We conducted 18 cognitive interviews with healthcare professionals in the United Kingdom (UK). We analysed the relevance, comprehensibility and comprehensiveness of items, including the potential for social desirability bias.

RESULTS

After research team consensus and initial feedback, we retained 40 items for cognitive interviewing. After our first round of interviews (n = 11), we removed 20 items, added three items and amended five items. After our second round of interviews (n = 7), we removed four items and amended three items. No major problems with relevance, comprehensibility, comprehensiveness or social desirability were found in remaining items.

CONCLUSIONS

The provisional version of the PSSS-HCP contains 19 items across three domains (stereotypes, prejudice, discrimination), demonstrating sufficient content validity. Our next step will be to perform a validation study to finalise item selection and explore the structure of the PSSS-HCP.

Workplace Mental Health Disclosure, Sustainable Employability and Well-Being at Work: A Cross-Sectional Study Among Military Personnel with Mental Illness

Purpose Disclosure of mental illness to a supervisor can have positive (e.g. supervisor support) and negative consequences (e.g. stigma). However, research on the association between disclosure and sustainable employability and well-being at work is scarce. The aim of this study was to investigate the association between the disclosure decision (yes/no), experiences with the decision (positive/negative) and sustainable employment and well-being at work among military personnel with mental illness (N = 323). Methods A cross-sectional questionnaire study was conducted. Descriptive and regression (linear and ordinal) analyses were performed. Comparisons were made between those with positive and negative disclosure experiences. Results Disclosure decision (yes/no) was not significantly associated with any of the measures of sustainable employability and well-being at work. However, positive disclosure experiences were significantly associated with higher scores on almost all measures of sustainable employability and well-being at work. Those with negative disclosure experiences reported significantly more shame (M_pos = 2.42, M_neg = 2.78, p < .05) and discrimination (M_pos = 1.70, M_neg = 2.84, p < .001). Those with a positive disclosure experience, reported significantly more supervisor support (M_pos = 3.20, M_neg = 1.94, p < .001). Conclusion We did not find evidence that the disclosure decision itself is related to measures of sustainable employment and well-being at work. In contrast, how participants had experienced their (non-)disclosure decision was significantly related to almost all measures. This emphasizes the importance of the work environments reactions to disclosure and mental illness in the workplace. Future research and interventions should focus on increasing the likelihood of positive disclosure experiences through creating a more inclusive work environment, with more supervisor support and less stigma.

Mental health issues and illness and substance use disorder (non-)disclosure to a supervisor: a cross-sectional study on beliefs, attitudes and needs of military personnel

OBJECTIVES

Research suggests that military personnel frequently delay disclosing mental health issues and illness (MHI), including substance use disorder, to supervisors. This delay causes missed opportunities for support and workplace accommodations which may help to avoid adverse occupational outcomes. The current study aims to examine disclosure-related beliefs, attitudes and needs, to create a better understanding of personnel's disclosure decision making.

DESIGN

A cross-sectional questionnaire study among military personnel with and without MHI. Beliefs, attitudes and needs regarding the (non-)disclosure decision to a supervisor were examined, including factors associated with (non-)disclosure intentions and decisions. Descriptive and regression (logistic and ordinal) analyses were performed.

SETTING

The study took place within the Dutch military.

PARTICIPANTS

Military personnel with MHI (n=324) and without MHI (n=554) were participated in this study.

OUTCOME MEASURE

(Non-)disclosure intentions and decisions.

RESULTS

Common beliefs and attitudes pro non-disclosure were the preference to solve one's own problems (68.3%), the preference for privacy (58.9%) and a variety of stigma-related concerns. Common beliefs and attitudes pro disclosure were that personnel wanted to be their true authentic selves (93.3%) and the desire to act responsibly towards work colleagues (84.5%). The most reported need for future disclosure (96.8%) was having a supervisor who shows an understanding for MHI. The following factors were associated both with non-disclosure intentions and decisions: higher preference for privacy (OR (95% CI))=(1.99 (1.50 to 2.65)_intention, 2.05 (1.12 to 3.76)_decision) and self-management (OR (95% CI))=(1.64 (1.20 to 2.23)_intention, 1.79 (1.00 to 3.20)_decision), higher stigma-related concerns (OR (95% CI))=(1.76 (1.12 to 2.77)_intention, 2.21 (1.02 to 4.79)_decision) and lower quality of supervisor-employee relationship (OR (95% CI))=(0.25 (0.15 to 0.42)_intention, 0.47 (0.25 to 0.87)_decision).

CONCLUSION

To facilitate (early-)disclosure to a supervisor, creating opportunities for workplace support, interventions should focus on decreasing stigma and discrimination and align with personnels' preference for self-management. Furthermore, training is needed for supervisors on how to recognise, and effectively communicate with, personnel with MHI. Focus should also be on improving supervisor-employee relationships.

Persistent somatic symptom related stigmatisation by healthcare professionals: A systematic review of questionnaire measurement instruments

OBJECTIVE

Patients with persistent somatic symptoms (PSS) experience stigmatising attitudes and behaviours by healthcare professionals. While previous research has focussed on individual manifestations of PSS related stigma, less is known about sound ways to measure stigmatisation by healthcare professionals towards patients with PSS. This review aims to assess the quality of questionnaire measurement instruments and make recommendations about their use.

METHODS

A systematic review using six databases (PubMed, Embase, CINAHL, PsycINFO, Open Grey and EThOS). The search strategy combined three search strings related to healthcare professionals, PSS and stigma. Additional publications were identified by searching bibliographies. Three authors independently extracted the data. Data analysis and synthesis followed COSMIN methodology for reviews of outcome measurement instruments.

RESULTS

We identified 90 publications that met the inclusion criteria using 62 questionnaire measurement instruments. Stereotypes were explored in 92% of instruments, prejudices in 52% of instruments, and discrimination in 19% of instruments. The development process of the instruments was not rated higher than doubtful. Construct validity, structural validity, internal consistency and reliability were the most commonly investigated measurement properties. Evidence around content validity was inconsistent or indeterminate.

CONCLUSION

No instrument provided acceptable evidence on all measurement properties. Many instruments were developed for use within a single publication, with little evidence of their development or establishment of content validity. This is problematic because stigma instruments should reflect the challenges that healthcare professionals face when working with patients with PSS. They should also reflect the experiences that patients with PSS have widely reported during clinical encounters.

Decision (not) to disclose mental health conditions or substance abuse in the work environment: a multiperspective focus group study within the military

OBJECTIVES

Many workers in high-risk occupations, such as soldiers, are exposed to stressors at work, increasing their risk of developing mental health conditions and substance abuse (MHC/SA). Disclosure can lead to both positive (eg, support) and negative (eg, discrimination) work outcomes, and therefore, both disclosure and non-disclosure can affect health, well-being and sustainable employment, making it a complex dilemma. The objective is to study barriers to and facilitators for disclosure in the military from multiple perspectives.

DESIGN

Qualitative focus groups with soldiers with and without MHC/SA and military mental health professionals. Sessions were audiotaped and transcribed verbatim. Content analysis was done using a general inductive approach.

SETTING

The study took place within the Dutch military.

PARTICIPANTS

In total, 46 people participated in 8 homogeneous focus groups, including 3 perspectives: soldiers with MHC/SA (N=20), soldiers without MHC/SA (N=10) and military mental health professionals (N=16).

RESULTS

Five barriers for disclosure were identified (fear of career consequences, fear of social rejection, lack of leadership support, lack of skills to talk about MHC/SA, masculine workplace culture) and three facilitators (anticipated positive consequences of disclosure, leadership support, work-related MHC/SA). Views of the stakeholder groups were highly congruent.

CONCLUSIONS

Almost all barriers (and facilitators) were related to fear for stigma and discrimination. This was acknowledged by all three perspectives, suggesting that stigma and discrimination are considerable barriers to sustainable employment and well-being. Supervisor knowledge, attitudes and behaviour were critical for disclosure, and supervisors thus have a key role in improving health, well-being and sustainable employment for soldiers with MHC/SA. Furthermore, adjustments could be made by the military on a policy level, to take away some of the fears that soldiers have when disclosing MHC/SA.

Barriers and facilitators for treatment-seeking for mental health conditions and substance misuse: multi-perspective focus group study within the military

BACKGROUND

Globally, millions are exposed to stressors at work that increase their vulnerability to develop mental health conditions and substance misuse (such as soldiers, policemen, doctors). However, these types of professionals especially are expected to be strong and healthy, and this contrast may worsen their treatment gap. Although the treatment gap in the military has been studied before, perspectives of different stakeholders involved have largely been ignored, even though they play an important role.

AIMS

To study the barriers and facilitators for treatment-seeking in the military, from three different perspectives.

METHOD

In total, 46 people participated, divided into eight homogeneous focus groups, including three perspectives: soldiers with mental health conditions and substance misuse (n = 20), soldiers without mental health conditions and substance misuse (n = 10) and mental health professionals (n = 16). Sessions were audio-taped and transcribed verbatim. Content analysis was done by applying a general inductive approach using ATLAS.ti-8.4.4 software.

RESULTS

Five barriers for treatment-seeking were identified: fear of negative career consequences, fear of social rejection, confidentiality concerns, the 'strong worker' workplace culture and practical barriers. Three facilitators were identified: social support, accessibility and knowledge, and healthcare within the military. The views of the different stakeholder groups were highly congruent.

CONCLUSIONS

Barriers for treatment-seeking were mostly stigma related (fear of career consequences, fear of social rejection and the 'strong worker' workplace culture) and this was widely recognised by all groups. Social support from family, peers, supervisors and professionals were identified as important facilitators. A decrease in the treatment gap for mental health conditions and substance misuse is needed and these findings provide direction for future research and destigmatising interventions.

Employment specialist competencies for supported employment programs

PURPOSE

Supported employment (SE) programs are evidence-based programs offered to people with severe mental illness to facilitate obtaining and keeping competitive work. However, significant variations in individuals' vocational success may be partly explained by differences in their employment specialists' competencies. Aim The main objectives of this study were to develop a questionnaire measuring the behaviors, attitudes and knowledge of employment specialists working in SE programs and to link specific competencies to vocational outcomes.

METHODS

A total of 153 employment specialists working in Canadian and Dutch supported employment programs completed the Behaviors, Attitudes, and Knowledge in Employment Specialists (BAKES) questionnaire and provided information about their clients' vocational outcomes.

RESULTS

Exploratory Factor Analyses results found 90 items over 12 subscales (e.g., Relationships with employers and supervisors). Regression analyses indicated that the two most useful subscales for predicting vocational success were: (1) Relationships with employers and supervisors, and (2) support and client-centered approach.

CONCLUSION

Employment specialists require specific competencies to help people with severe mental illness obtain and maintain competitive employment. Validating the BAKES will better define the broad range of competencies expected for this position, and this tool may facilitate training of employment specialists.

Psychometric evaluation of the Dutch version of the mental health recovery measure (MHRM)

BACKGROUND

During the past decade, the mental health consumer movement has drawn the attention of mental health providers, researchers and policy makers to the concept of recovery. Traditionally, recovery primarily refers to the remission of symptoms. Nowadays, recovery is also regarded in a sense that all individuals, even those with severe psychiatric disabilities, can improve. Accordingly, recovery for people with severe mental illness refers to hope and optimism, empowerment, regained control and increased self-esteem, illness self-management and engagement in meaningful daily activities (Corrigan, Giffort, Rashid, Leary & Okeke, 1999; Jacobson & Greenley, 2001; Leamy, Bird, le Boutillier, Williams & Slade, 2011; van Gestel-Timmermans, Brouwers, van Assen, Bongers & van Nieuwenhuizen, 2012). Little empirical research, however, has been done and instruments to measure recovery are scarce.

AIMS

In the current study, the psychometric properties of the Dutch version of the Mental Health Recovery Measure (MHRM) are explored. Convergent and divergent validity of the MHRM was assessed using standardized measures of hope (Hope Herth Index (HHI)), recovery-promoting professional competence (Recovery Promoting Relationships Scale (RPRS)) and general physical health and well-being (RAND Measure of Health-Related Quality of Life (RAND-36)).

METHODS

A factor analysis was conducted and Cronbach's α of the MHRM scales was assessed. The construct validity was assessed by computing the intercorrelations of the MHRM, HHI, RPRS and RAND-36.

RESULTS

Data were available for 212 patients: 70 patients completed the MHRM, HHI and RAND 36 and 142 filled out the MHRM and RPRS. Exploratory factor analysis resulted in an interpretable three-factor solution. Cronbach's α ranged from 0.86 to 0.94. The convergent validity of the instrument was satisfactory; the divergent validity was less clear.

CONCLUSIONS

This study offers evidence to suggest that the Dutch version of the MHRM is a reliable measure (in terms of internal consistency) with a generally acceptable convergent and divergent validity. Further research is needed to clarify the extent to which the MHRM is sensitive enough to capture the individual recovery process of patients.

Hope as a determinant of mental health recovery: a psychometric evaluation of the Herth Hope Index-Dutch version

Hope is an important aspect of mental health recovery and a major concern in patients with mental illness. Therefore, an instrument to measure hope could be useful for clinical settings and research. The aim of this study was to develop a Dutch version of the Herth Hope Index (HHI-Dutch) and to evaluate its validity and reliability in a sample of people with severe mental illness. The HHI-Dutch was used in a sample of people with severe mental illness (n=341). A Principal Component Analysis with varimax rotation was performed and identified two factors. The results also showed a Cronbach's alpha of 0.84 for the HHI total score and a test-retest reliability of r=0.79. As for convergent validity, highest correlations were found between hope and health-related self-efficacy beliefs (r=0.72), perceived quality of life (r=0.56) and mental health (r=0.59) and medium correlations between hope and loneliness (r= -0.47), task-oriented coping (r=0.45) and the habit to seek company (r=0.4). As for divergent validity, according to expectations, there was no significant correlation between hope and physical functioning, but there was a positive correlation between hope and general health perception (r=0.34). In conclusion, the HHI-Dutch has shown to be an instrument with adequate psychometrical properties. It is advisable to use the scale as a whole rather than using the subscales. The HHI-Dutch is appropriate for research in the recovery process of people with severe mental illness. Moreover, the study of hope is important for understanding the concept of hope in relation to mental health recovery. The results of this study may be a step forward and a new impulse to stimulate research on the important 'hope' aspect in mental health recovery.

Hope as a determinant of mental health recovery: a psychometric evaluation of the Herth Hope Index-Dutch version

Hope is an important aspect of mental health recovery and a major concern in patients with mental illness. Therefore, an instrument to measure hope could be useful for clinical settings and research. The aim of this study was to develop a Dutch version of the Herth Hope Index (HHI-Dutch) and to evaluate its validity and reliability in a sample of people with severe mental illness. The HHI-Dutch was used in a sample of people with severe mental illness (n=341). A Principal Component Analysis with varimax rotation was performed and identified two factors. The results also showed a Cronbach's alpha of 0.84 for the HHI total score and a test-retest reliability of r=0.79. As for convergent validity, highest correlations were found between hope and health-related self-efficacy beliefs (r=0.72), perceived quality of life (r=0.56) and mental health (r=0.59) and medium correlations between hope and loneliness (r= -0.47), task-oriented coping (r=0.45) and the habit to seek company (r=0.4). As for divergent validity, according to expectations, there was no significant correlation between hope and physical functioning, but there was a positive correlation between hope and general health perception (r=0.34). In conclusion, the HHI-Dutch has shown to be an instrument with adequate psychometrical properties. It is advisable to use the scale as a whole rather than using the subscales. The HHI-Dutch is appropriate for research in the recovery process of people with severe mental illness. Moreover, the study of hope is important for understanding the concept of hope in relation to mental health recovery. The results of this study may be a step forward and a new impulse to stimulate research on the important 'hope' aspect in mental health recovery.

Development of sandwich-type ELISAs for the quantification of rat and murine thrombin activatable fibrinolysis inhibitor in plasma

BACKGROUND

Altered plasma levels of thrombin activatable fibrinolysis inhibitor (TAFI) are associated with a large number of pathologies. Rat and murine models are frequently used to study the pathophysiological role of TAFI in vivo but immunological tools to quantify rat and murine TAFI are lacking.

OBJECTIVE

The production of monoclonal antibodies (mAb) towards rat TAFI and the development of an ELISA for the quantification of rat and murine TAFI in plasma.

METHODS AND RESULTS

Monoclonal antibodies were raised in TAFI-deficient mice towards (activated) recombinant rat TAFI. Pair-wise testing of the mAb revealed three suitable ELISA combinations, namely RT36A3F5/RT30D8-HRP, RT36A3F5/RT82F12-HRP and RT82F12/RT36A3F5-HRP. All three ELISAs are highly specific for rat and murine TAFI. TAFI concentrations in the lower ng mL(-1) range can be determined in plasma samples with a high reproducibility. Comparing TAFI antigen levels measured by these ELISAs with TAFIa activity values determined by activity based assays revealed excellent correlations (R(2) > 0.98). The average antigen levels of 20 individual rat plasma samples were 16 +/- 2 microg mL(-1) using the RT36A3F5-RT30D8-HRP, 12 +/- 2 microg mL(-1) using the RT36A3F5-RT82F12-HRP and 21 +/- 2 microg mL(-1) using the RT82F12-RT36A3F5-HRP ELISA. The determined antigen levels in rat plasma are similar to the levels reported for human plasma.

CONCLUSIONS

We developed three highly specific and extremely sensitive sandwich-type ELISAs for the quantification of rat and murine TAFI in plasma. The described ELISAs will facilitate in vivo investigation on the pathophysiological role of TAFI.

Effect of improving flue gas cleaning on characteristics and immobilisation of APC residues from MSW incineration

The flue gas cleaning system of a MSW incinerator with a capacity of 350 kt/year was changed to improve the HCl elimination efficiency. Instead of the semi-wet operating spray reactor and subsequent baghouse, a two-step wet flue gas cleaning was added behind the baghouse. Elemental composition, X-ray powder diffraction patterns and TGA measurements showed that the resulting APC residue was totally different from the former residue. As a consequence, leaching characteristics of both residues also differed and another treatment was required prior to disposal. For the former residue, mainly leaching of Pb (>100 mg/l), necessitated treatment prior to landfilling. The lower alkalinity of the new residue resulted in a leachate pH of 9.7 and a Pb concentration of 0.8 mg/l. The leachate pH of the former residue was 12.4. The leaching of Pb and Zn increased above 100 mg/l when immobilising the new residue with cement. Better results were obtained when immobilising with micro silica. The high CaCl2 x 2H2O content of the new residue brought along clogging of the bag filter system. Adding 1.4% of CaO (or 1.9% of Ca(OH)2) to the residue already improved these inconveniences but again significantly changed the leaching behaviour of the residue.

The distal hinge of the reactive site loop and its proximity: a target to modulate plasminogen activator inhibitor-1 activity

The serpin plasminogen activator inhibitor type 1 (PAI-1) plays a regulatory role in various physiological processes (e.g. fibrinolysis and pericellular proteolysis) and forms a potential target for therapeutic interventions. In this study we identified the epitopes of three PAI-1 inhibitory monoclonal antibodies (MA-44E4, MA-42A2F6, and MA-56A7C10). Differential cross-reactivities of these monoclonals with PAI-1 from different species and sequence alignments between these PAI-1s, combined with the three-dimensional structure, revealed several charged residues as possible candidates to contribute to the respective epitopes. The production, characterization, and subsequent evaluation of a variety of alanine mutants using surface plasmon resonance revealed that the residues His(185), Arg(186), and Arg(187) formed the major sites of interaction for MA-44E4. In contrast, the epitopes of MA-42A2F6 and MA-56A7C10 were found to be conformational. The epitope of MA-42A2F6 comprises residues Lys(243) and Glu(350), whereas the epitope of MA-56A7C10 comprises residues Glu(242), Lys(243), Glu(244), Glu(350), Asp(355), and Arg(356). The participation of Glu(350), Asp(355), and Arg(356) provides a molecular explanation for the differential exposure of this epitope in the different conformations of PAI-1 and for the effect of these antibodies on the kinetics of the formation of the initial PAI-1-proteinase complexes. The localization of the epitopes of MA-44E4, MA42A2F6, and MA-56A7C10 elucidates two previously unidentified molecular mechanisms to modulate PAI-1 activity and opens new perspectives for the rational development of PAI-1 neutralizing compounds.

Identification of a target site in plasminogen activator inhibitor-1 that allows neutralization of its inhibitor properties concomitant with an allosteric up-regulation of its antiadhesive properties

The serpin plasminogen activator inhibitor-1 (PAI-1) has a dual function: 1) it plays an important role as a direct inhibitor of the plasminogen activation system, and 2) its interaction with the adhesive glycoprotein vitronectin suggests a role in tissue remodeling and metastasis, independent from its proteinase inhibitory properties. Unique to this serpin is the close association between its conformational and functional properties. Indeed, PAI-1 can occur in an active and a latent conformation, but both functions are exclusively present in the active conformation. We report here the epitope localization and functional effects of a monoclonal antibody (MA-124K1) that inhibits rat PAI-1 activity and simultaneously increases the binding of inactive PAI-1 to vitronectin (the affinity constant of PAI-1 for vitronectin is 2 x 10(7) m(-1) in the absence of MA-124K1 and 160 x 10(7) m(-1) in the presence of MA-124K1). To the best of our knowledge, this is the first monoclonal antibody dissociating the proteinase inhibitory properties from the vitronectin binding properties in PAI-1. Mutation of Glu(212) and/or Glu(220) in rat PAI-1 to Ala results in a strongly reduced affinity or absence of binding to MA-124K1. The three-dimensional structure of PAI-1 reveals that these residues constitute a conformational epitope close to the reactive-site loop and compatible with the effect of MA-124K1 on the inhibitory properties of PAI-1. However, the vitronectin binding site is localized at the opposite site of the molecule, indicating that the effect of MA-124K1 involves an allosteric modulation of the vitronectin binding site. Cell culture experiments revealed a significant reduction of cell attachment and migration in the presence of MA-124K1, providing evidence for the functional relevance of this antibody-mediated up-regulation of the vitronectin binding properties of PAI-1. In conclusion, a novel mechanism for interference with PAI-1 functions has been identified and is of importance in the modulation of cell migration and related events (e.g. tumor metastasis).

Immunoassays for the quantitation of porcine PAI-1 antigen and activity in biological fluid samples

Two monoclonal antibody-based enzyme-linked immunosorbent assays (ELISAs) for the quantitation of porcine plasminogen activator inhibitor-1 (PAI-1) antigen and activity in plasma were constructed and validated. The intra-assay, interassay, and interdilution coefficients of variation were 4.3, 13, and 8%, respectively, for the antigen ELISA and 5, 16, and 11% for the activity assay. Assay recoveries, in the antigen ELISA. of either latent or active recombinant porcine PAI-1 (10 and 50 ng/ml) added to plasma were 86 +/- 9% and 92 +/- 22%, respectively, for the latent form and 89 +/- 99% and 87 +/- 7% for the active form (mean +/- SD, n = 3 to 4). In the immunofunctional assay, recoveries for the same concentrations of active PAI-1 were 108 +/- 16% and 92 +/- 21%, respectively. In male porcine plasma the level of PAI-1 antigen was 31 +/- 11 ng/ ml and the activity, 34 +/- 16 ng/ml (mean +/- SD, n = 10). In female plasma PAI-1 antigen levels were 20 +/- 5.2 ng/ml and the PAI-1 activity 42 +/- 17 ng/ml (n = 13). A linear correlation was found between PAI-1 antigen and activity levels in male (r = 0.60) and female (r = 0.70) plasma. Immunodepletion resulted in a decrease of >95% of the original PAI-1 antigen or activity levels. Incubation of plasma samples at 37 degrees C for 16 h resulted in a significant decrease (70 to 85%) of PAI-1 activity. Under these conditions (37 degrees C, 16 h) PAI-1 antigen levels remained unchanged in males whereas the response of the female samples in the PAI-1 antigen assay increased two-fold. In lysed platelet-rich plasma males had 990 +/- 470 ng/ml antigen and 160 +/- 80 ng/ml activity and females, 920 +/- 500 ng/ml antigen and 150 +/- 98 ng/ml activity corresponding to 2.1 +/- 0.77 fg PAI-1 antigen per platelet. Only 16% of PAI-1 released from platelets was found to be active. Linear correlations between PAI-1 antigen and activity were found for both males (r = 0.61) and females (r = 0.67). The assays are both sensitive and specific and may, therefore, aid the elucidation of the pathophysiological role of PAI-1 in swine experimental models of atherosclerosis and other thrombotic disorders.

DSM-III-R and ICD-10 personality disorder features among women experiencing two types of self-reported homesickness: an exploratory study

This study investigated the intensity of DSM-III-R and ICD-10 personality disorder features among females experiencing self-reported homesickness. Three groups were compared: (a) a group of women experiencing chronic feelings of homesickness (CHS); (b) a group of women experiencing episodic attacks of homesickness, each time they go on holidays (EHS); and (c) a group of healthy control females, recruited from the general population (HC). This study aimed to investigate whether the homesick participants showed stronger features of personality pathology than the controls and whether those who report experiencing chronic feelings of homesickness showed stronger features of personality pathology than those who at the moment of testing were not in an actual state of homesickness. Glass effect sizes revealed that the DSM-III-R avoidant and dependent and the ICD-10 anxious and dependent traits were most strongly associated with either type of homesickness. Finally, CHS was particularly associated with passive-aggressive traits and EHS with sadistic traits. Based on the stories of 21 homesick women, a link between adverse attachment experiences in childhood and certain personality features on the one hand and homesickness on the other is tentatively suggested.

Correlation between oxidized low density lipoproteins and von Willebrand factor in chronic renal failure

An ELISA specific for a wide spectrum of oxidized apo B-100 in OxLDL was developed and applied to blood samples from 27 control subjects, 20 mild chronic renal failure (MCRF) patients, 21 severe chronic renal failure patients on conservative treatment (SCRF) and 56 severe chronic renal failure patients on maintenance hemodialysis (HEMO). Mean levels of OxLDL were 0.59 mg/dl in controls (95% CI, 0.52-0.66 mg/dl), and were 2.7-fold (p < 0.01), 3.1-fold (p < 0.001) and 5.4-fold (p < 0.001) higher in MCRF, SCRF and HEMO patients, respectively. Levels of von Willebrand factor, a marker of endothelial injury, were 100 percent in controls (95% CI, 90-110 percent), and were 1.5-fold (p = NS), 1.6-fold (p < 0.01) and 2.1-fold (p < 0.001) higher in MCRF, SCRF and HEMO patients, respectively. Multiple regression analysis revealed that the extent of renal failure (F = 14; p = 0.0004) accounted for a significant fraction of the variation in OxLDL levels, also after exclusion of patients with evidence of ischemic atherosclerotic disease (F = 21; p = 0.0001). After adjustment for the extent of renal failure, hemodialysis (F = 5.6; p = 0.021) and LDL cholesterol levels (F = 7.1, p = 0.0095) contributed significantly to the variation in OxLDL levels. Whereas the extent of renal failure contributed only marginally to the individual variations in vWF levels (F = 4.1; p = 0.048), these levels correlated significantly with plasma levels of OxLDL (F = 26; p = 0.0001). In conclusion, OxLDL increase progressively during the development of renal failure suggesting that the oxidation of LDL may be associated with endothelial injury and atherogenesis in these patients.

Phospholipid binding and lecithin-cholesterol acyltransferase activation properties of apolipoprotein A-I mutants

Recombinant human apolipoprotein A-I (apo A-I) and three deletion mutants: apo A-I(delta Leu44-Leu126), apo A-I(delta Glu139-Leu170), and apo A-I(delta Ala190-Gln243), purified from the periplasmic space of Escherichia coli, were studied. The rate of turbidity decrease following mixing of apo A-I(delta Ala190-Gln243) with dimyristoylphosphatidylcholine (DMPC) vesicles at 23 degrees C was 10-fold lower than that of the other apo A-I proteins, confirming that the carboxy-terminal region of apo A-I plays a role in rapid lipid binding. The Stokes radii of reconstituted high-density lipoproteins (rHDL), containing dipalmitoylphosphatidylcholine and cholesterol, were larger for the three apo A-I mutants [6.3 nm for apo A-I(delta Leu44-Leu126), 6.1 nm for apo A-I(delta Glu139-Leu170), and 6.5 nm for apo A-I(delta Ala190-Gln243)] than for intact apo A-I (5.0 nm). The mutant rHDL all contained 4 apo A-I molecules per particle as compared to 2 for intact apo A-I. Circular dichroism measurements revealed 8 alpha-helices per apo A-I molecule, 5 per apo A-I(delta Leu44-Leu126), 6 per apo A-I(delta Glu139-Leu170), and 4 per apo A-I(delta Ala190-Gln243) molecule as compared to predicted values of 8, 5, 6, and 6 alpha-helices, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Malondialdehyde-modified low density lipoproteins in patients with atherosclerotic disease

The murine monoclonal antibody mAb-1H11 raised against malondialdehyde (MDA)-modified LDL, was used to detect cross-reacting material in human atheromatous tissue and in plasma. MDA-modified LDL levels in plasma were 0.19 +/- 0.02 mg/dl (mean +/- SEM) in 44 control subjects, 0.24 +/- 0.02 mg/dl in 15 patients with chronic stable angina pectoris (P = NS vs LDL cholesterol matched controls), 1.4 +/- 0.1 mg/dl in 60 patients with acute myocardial infarction (P < 0.001 vs controls), and 0.86 +/- 0.11 mg/dl in 22 patients with carotid atherosclerosis (P < 0.001 vs controls). Modified LDL, isolated from pooled LDL of 10 patients, showed a higher electrophoretic mobility on agarose gels, a higher content of thiobarbituric acid reactive substances, and a higher cholesterol/protein ratio than native LDL and had a similar reactivity (antigen/protein ratio) in the assay as the in vitro MDA-modified LDL used for calibration. Its apo B-100 moiety was not fragmented. Uptake of this modified LDL by macrophages resulted in foam cell generation. In conclusion, elevated plasma levels of atherogenic MDA-modified LDL may be a marker for unstable atherosclerotic cardiovascular disease.

Stimulation with a monoclonal antibody (mAb4E4) of scavenger receptor-mediated uptake of chemically modified low density lipoproteins by THP-1-derived macrophages enhances foam cell generation

mAb4E4, a murine monoclonal antibody that is specific for acetylated LDL and malondialdehyde-treated LDL, binds specifically to modified LDL present in human atherosclerotic lesions. It is directed against an epitope that is poorly exposed in delipidated and solubilized apolipoprotein B-100 from modified LDL. mAb4E4, as well as its F(ab')2 and Fab fragments, enhanced the uptake of both acetylated LDL and malondialdehyde-treated LDL by THP-1-derived macrophages resulting in a sixfold increase of cytoplasmic cholesteryl ester levels. The increased uptake of modified LDL/mAb4E4 complexes did not occur via the Fc receptor and did not depend on aggregation of modified LDL particles. However, their uptake was inhibited by blocking the scavenger receptors with fucoidin or by downregulation of receptor expression with endotoxins or interferon-gamma, indicating that their uptake is mediated via these receptors. Thus, generation of autoimmune antibodies against modified LDL and subsequent endocytosis of soluble modified LDL/antibody complexes via scavenger receptors may enhance foam cell generation. This mechanism may contribute to the progression of atherosclerotic lesions.

Biochemical characterization of single-chain chimeric plasminogen activators consisting of a single-chain Fv fragment of a fibrin-specific antibody and single-chain urokinase

K12G0S32 is a 57-kDa recombinant single-chain chimeric plasminogen activator consisting of scFv-K12Go, a single-chain variable-region antigen-binding fragment (Fv) of the monoclonal antibody MA-15C5, which is specific for fragment D-dimer of human cross-linked fibrin, and a low-molecular-mass (33 kDa) urokinase-type plasminogen activator (u-PA-33k) containing amino acids Ala132-Leu411 (Holvoet, P., Laroche, Y., Lijnen, H. R., Van Cauwenberghe, R., Demarsin, E., Brouwers, E., Matthyssens, G. & Collen D. (1991) J. Biol. Chem. 266, 19717-19724). In addition, the Arg156-Phe157 thrombin-cleavage site in the u-PA moiety of K12G0S32 is removed by substitution of Phe157 with Asp. In the present study, the fibrinolytic potency of K12G0S32, determined in a system composed of a 125I-fibrin-labeled human plasma clot submerged in citrated plasma, was found to be only twofold higher than that of intact single-chain u-Pa (rscu-PA), but 17-fold higher than that of rscu-PA(M), a variant of rscu-PA in which the thrombin-cleavage site was removed by substitution of Phe157 with Asp. The fibrinolytic potency of K12G0S32T, with an intact thrombin-cleavage site, was 6-15-fold higher than that of rscu-PA. Conversion of 1 microM single-chain K12G0S32 or rscu-PA(M) into their two-chain derivatives with plasmin occurred at a rate of 1.0 +/- 0.15 nmol.min-1.nmol plasmin-1 and 0.85 +/- 0.074 nmol.min-1.nmol plasmin-1, compared to 14 +/- 2.3 nmol.min-1.nmol plasmin-1 and 18 +/- 2.6 nM.min-1.nmol plasmin-1 for K12G0S32T and rscu-PA, respectively. Purified fragment D-dimer of human cross-linked fibrin inhibited the fibrinolytic potency of single-chain K12G0S32T, but not of two-chain K12G0S32T, in a dose-dependent manner. Furthermore, the fibrinolytic potencies of two-chain K12G0S32 and K12G0S32T were not significantly higher than those of recombinant two-chain u-PA (rtcu-PA) or of rtcu-PA(M). These findings suggest that the 59-fold increase in fibrinolytic potency of K12G0S32T, relative to that of rscu-PA(M), is due both to targeting of the activator to the clot via the single-chain Fv fragment (sixfold increase) and to a more efficient conversion of single-chain K12G0S32T to its two-chain derivative (eightfold increase). Thus, targeting to clots by means of fibrin-specific antibodies results in a significant increase of the fibrinolytic potency of single-chain but not of two-chain u-PA.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of a chimeric plasminogen activator consisting of a single-chain Fv fragment derived from a fibrin fragment D-dimer-specific antibody and a truncated single-chain urokinase

An Mr 57,000 single-chain chimeric plasminogen activator, K12G0S32, consisting of a variable region fragment (Fv) derived from the fibrin fragment D-dimer-specific monoclonal antibody MA-15C5 and of a 33-kDa (amino acids Ala132 to Leu411) recombinant single-chain urokinase-type plasminogen activator (rscu-PA-33k) was studied. K12G0S32, secreted by infected Spodoptera frugiperda insect cells at a rate of 1.5 micrograms/10(6) cells/48 h, was purified to homogeneity by ion-exchange chromatography and gel filtration. It was obtained essentially as a single-chain molecule with a Ka = 5.5 x 10(9) M-1 for immobilized fragment D-dimer, similar to that of MA-15C5. The specific activity of both its single-chain and two-chain forms on fibrin plates was 100,000 IU/mg of urokinase-type plasminogen activator (u-PA) equivalent. Activation of plasminogen by two-chain K12G0S32 obeyed Michaelis-Menten kinetics with Km = 2.9 +/- 0.6 microM and a k2 = 3.7 +/- 0.6 s-1 (mean +/- S.D.; n = 3), as compared to Km = 12 microM and k2 = 4.8 s-1 for rtcu-PA-32k (recombinant low Mr two-chain u-PA consisting of amino acids Leu144 to Leu411). Single-chain K12G0S32 induced a dose- and time-dependent lysis of a 125I-fibrin-labeled human plasma clot immersed in citrated human plasma; 50% lysis in 2 h was obtained with 0.70 +/- 0.07 micrograms/ml (mean +/- S.D.; n = 5), as compared with 8.8 +/- 0.1 micrograms/ml for rscu-PA-32k (recombinant low Mr single-chain u-PA consisting of amino acids Leu144 to Leu411) (mean +/- S.D.; n = 3). With two-chain K12G0S32, 50% clot lysis in 2 h required 0.25 +/- 0.03 micrograms/ml (mean +/- S.D.; n = 3), as compared with only 0.62 +/- 0.04 micrograms/ml (mean +/- S.D.; n = 2) for rtcu-PA-32k. These results indicate that low Mr single-chain u-PA can be targeted to a fibrin clot with a single-chain Fv fragment of a fibrin-specific antibody, resulting in a 13-fold increase of the fibrinolytic potency of the single-chain form and a 2.5-fold increase of the potency of the two-chain form.

Dideoxycytidine alone and in an alternating schedule with zidovudine in children with symptomatic human immunodeficiency virus infection

OBJECTIVE

To determine whether a short course of 2',3'-dideoxycytidine (ddC) could provide safe antiretroviral activity in children with symptomatic human immunodeficiency virus infection and whether it could be used with azidothymidine (AZT, zidovudine). The goal was to maintain uninterrupted antiretroviral therapy while sparing AZT-related myelosuppression and ddC-related neuropathy.

METHODS

In a pilot study, we evaluated four dosage levels of ddC--0.015, 0.02, 0.03, and 0.04 mg/kg, given orally every 6 hours--in 15 children between 6 months and 13 years of age with Centers for Disease Control P2 (i.e., symptomatic) human immunodeficiency virus infection. Thirteen patients had not had any prior antiretroviral therapy; two patients had received and benefited from AZT, but dose-limiting neutropenia had developed. At each dosage level, ddC was given for 8 consecutive weeks and then stopped. After a 30-day rest, a schedule of ddC for 1 week was followed by 3 weeks of AZT therapy (180 mg/m2 every 6 hours); this alternating schedule was repeated for as long as tolerated. Age-appropriate psychometric testing was performed before the start of ddC therapy and after 8 weeks.

RESULTS

During the 8 weeks of therapy with ddC alone, no neutropenia or anemia was observed; 6 of 9 patients had decreases in p24 antigen levels, and 8 of 15 had an increased CD4 cell count. At the 0.04 mg/kg level, a rash developed in three patients; mild mouth sores developed in 9 of 15 patients. On the alternating ddC/AZT schedule, no neuropathy was observed.

CONCLUSIONS

2',3'-Dideoxycytidine has antiretroviral activity in some children and appears to be safe for short intervals. Longer courses of ddC at lower dosage levels, and schedules integrating ddC into combination regimens, deserve to be explored.