Predicting prognosis for adults with depression using individual symptom data: a comparison of modelling approaches

BACKGROUND

This study aimed to develop, validate and compare the performance of models predicting post-treatment outcomes for depressed adults based on pre-treatment data.

METHODS

Individual patient data from all six eligible randomised controlled trials were used to develop (k = 3, n = 1722) and test (k = 3, n = 918) nine models. Predictors included depressive and anxiety symptoms, social support, life events and alcohol use. Weighted sum scores were developed using coefficient weights derived from network centrality statistics (models 1-3) and factor loadings from a confirmatory factor analysis (model 4). Unweighted sum score models were tested using elastic net regularised (ENR) and ordinary least squares (OLS) regression (models 5 and 6). Individual items were then included in ENR and OLS (models 7 and 8). All models were compared to one another and to a null model (mean post-baseline Beck Depression Inventory Second Edition (BDI-II) score in the training data: model 9). Primary outcome: BDI-II scores at 3-4 months.

RESULTS

Models 1-7 all outperformed the null model and model 8. Model performance was very similar across models 1-6, meaning that differential weights applied to the baseline sum scores had little impact.

CONCLUSIONS

Any of the modelling techniques (models 1-7) could be used to inform prognostic predictions for depressed adults with differences in the proportions of patients reaching remission based on the predicted severity of depressive symptoms post-treatment. However, the majority of variance in prognosis remained unexplained. It may be necessary to include a broader range of biopsychosocial variables to better adjudicate between competing models, and to derive models with greater clinical utility for treatment-seeking adults with depression.

POS1127 USE OF ARTIFICIAL INTELLIGENCE AND CLOUD-BASED INFRASTRUCTURE TO IMPROVE THE SPEED AND ACCURACY OF ELIGIBILITY READS IN OSTEOARTHRITIS TRIALS

Background

The Kellgren-Lawrence grading (KLG) system is used in clinical trials of osteoarthritis (OA) to define the structural severity of the disease as part of patient eligibility assessment. However, the use of KLG system has proven to be challenging due to considerable inter-reader variability[1], [2], which may result in recruitment of sub-optimal patient cohort or delays in patient recruitment.

Objectives

The objective of this study was to determine the impact of an AI-assisted, cloud-based data management system on the rate of adjudication and the speed of OA patient recruitment.

Methods

A total of 3855 bilateral fixed-flexion posteroanterior radiographs of the tibiofemoral joints from global multi-centre trials were included in this study. Two experienced readers performed an initial KLG assessment of both knees; the adjudication was performed by a third experienced reader. A cloud-based imaging data management system was deployed, the readers could access the data simultaneously and adjudication was automatically triggered.

We quantified the adjudication rate and the distribution of disagreements in KLG scores provided by the initial readers. Furthermore, the delay in delivery time of the KLG reports to the recruiting site was recorded.

Results

48% (1836) of the initial reads required adjudication. Approximately 70% of the disagreements affected the conventional KLG 2-3 inclusion range of OA clinical trials. Use of the cloud-based data management allowed 41% of the reports to be delivered within 24 hours, if no adjudication was required vs an average of 5 days as estimated based on the readers’ prior experience.

Table 1 provides details on the distribution of disagreements resulting in adjudication reads. Figure 1 shows the delivery time for KLG with and without adjudication.

Table 1.

Distribution of disagreements of initial reads resulting in an adjudication read being triggered.

Disagreement triggering AdjudicationNumber of CasesPercentageKLG 0 – 171327.8%KLG 1 – 282031.9%KLG 2 – 348218.7%KLG 3 – 444617.4%Other1104.3%Total2569100%Figure 1.

Time to deliver eligibility report

Nehrer et al. showed that assisting the readers with AI generated KLG scoring reports, the agreement rate between readers for KLG assessment increased by 21% [2]. Adding to this, 30% of the adjudications (stemming from KLG 0 –1 disagreements between readers) could be avoided when using AI generated reports.

Conclusion

We assess the rate of adjudication and speed of reporting of KLG of data from multi-centre OA clinical trials. Future work is planned to assess the effect of AI-assisted OA grading systems within our cloud-based data management system on reader agreement and recruitment speed in global clinical trials.

References

[1]D. J. Hunter et al., “OARSI Clinical Trials Recommendations: Knee imaging in clinical trials inosteoarthritis,” Osteoarthritis and Cartilage, vol. 23, no. 5. W.B. Saunders Ltd, pp. 698–715, 2015. doi: 10.1016/j.joca.2015.03.012.

[2]S. Nehrer et al., “Automated Knee Osteoarthritis Assessment Increases Physicians’ Agreement Rate and Accuracy: Data from the Osteoarthritis Initiative,” Cartilage, vol. 13, no. 1_suppl, pp. 957S-965S, Dec. 2021, doi: 10.1177/1947603519888793.

Disclosure of Interests

Olga Kubassova Grant/research support from: Takeda, Lilly, Abbvie, Pfizer, Mikael Boesen Speakers bureau: Lilly, Novartis, Abbvie, Pfizer, Cristiano Pereira da Costa: None declared, Julia O’Lynn: None declared, Andrew Patterson: None declared, Dimitri Kessler: None declared

Role of age, gender and marital status in prognosis for adults with depression: An individual patient data meta-analysis

AIMS

To determine whether age, gender and marital status are associated with prognosis for adults with depression who sought treatment in primary care.

METHODS

Medline, Embase, PsycINFO and Cochrane Central were searched from inception to 1st December 2020 for randomised controlled trials (RCTs) of adults seeking treatment for depression from their general practitioners, that used the Revised Clinical Interview Schedule so that there was uniformity in the measurement of clinical prognostic factors, and that reported on age, gender and marital status. Individual participant data were gathered from all nine eligible RCTs (N = 4864). Two-stage random-effects meta-analyses were conducted to ascertain the independent association between: (i) age, (ii) gender and (iii) marital status, and depressive symptoms at 3-4, 6-8, and 9-12 months post-baseline and remission at 3-4 months. Risk of bias was evaluated using QUIPS and quality was assessed using GRADE. PROSPERO registration: CRD42019129512. Pre-registered protocol https://osf.io/e5zup/.

RESULTS

There was no evidence of an association between age and prognosis before or after adjusting for depressive 'disorder characteristics' that are associated with prognosis (symptom severity, durations of depression and anxiety, comorbid panic disorderand a history of antidepressant treatment). Difference in mean depressive symptom score at 3-4 months post-baseline per-5-year increase in age = 0(95% CI: -0.02 to 0.02). There was no evidence for a difference in prognoses for men and women at 3-4 months or 9-12 months post-baseline, but men had worse prognoses at 6-8 months (percentage difference in depressive symptoms for men compared to women: 15.08% (95% CI: 4.82 to 26.35)). However, this was largely driven by a single study that contributed data at 6-8 months and not the other time points. Further, there was little evidence for an association after adjusting for depressive 'disorder characteristics' and employment status (12.23% (-1.69 to 28.12)). Participants that were either single (percentage difference in depressive symptoms for single participants: 9.25% (95% CI: 2.78 to 16.13) or no longer married (8.02% (95% CI: 1.31 to 15.18)) had worse prognoses than those that were married, even after adjusting for depressive 'disorder characteristics' and all available confounders.

CONCLUSION

Clinicians and researchers will continue to routinely record age and gender, but despite their importance for incidence and prevalence of depression, they appear to offer little information regarding prognosis. Patients that are single or no longer married may be expected to have slightly worse prognoses than those that are married. Ensuring this is recorded routinely alongside depressive 'disorder characteristics' in clinic may be important.

The importance of transdiagnostic symptom level assessment to understanding prognosis for depressed adults: analysis of data from six randomised control trials

BACKGROUND

Depression is commonly perceived as a single underlying disease with a number of potential treatment options. However, patients with major depression differ dramatically in their symptom presentation and comorbidities, e.g. with anxiety disorders. There are also large variations in treatment outcomes and associations of some anxiety comorbidities with poorer prognoses, but limited understanding as to why, and little information to inform the clinical management of depression. There is a need to improve our understanding of depression, incorporating anxiety comorbidity, and consider the association of a wide range of symptoms with treatment outcomes.

METHOD

Individual patient data from six RCTs of depressed patients (total n = 2858) were used to estimate the differential impact symptoms have on outcomes at three post intervention time points using individual items and sum scores. Symptom networks (graphical Gaussian model) were estimated to explore the functional relations among symptoms of depression and anxiety and compare networks for treatment remitters and those with persistent symptoms to identify potential prognostic indicators.

RESULTS

Item-level prediction performed similarly to sum scores when predicting outcomes at 3 to 4 months and 6 to 8 months, but outperformed sum scores for 9 to 12 months. Pessimism emerged as the most important predictive symptom (relative to all other symptoms), across these time points. In the network structure at study entry, symptoms clustered into physical symptoms, cognitive symptoms, and anxiety symptoms. Sadness, pessimism, and indecision acted as bridges between communities, with sadness and failure/worthlessness being the most central (i.e. interconnected) symptoms. Connectivity of networks at study entry did not differ for future remitters vs. those with persistent symptoms.

CONCLUSION

The relative importance of specific symptoms in association with outcomes and the interactions within the network highlight the value of transdiagnostic assessment and formulation of symptoms to both treatment and prognosis. We discuss the potential for complementary statistical approaches to improve our understanding of psychopathology.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm

We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.

The Mars 2020 Engineering Cameras and Microphone on the Perseverance Rover: A Next-Generation Imaging System for Mars Exploration

The Mars 2020 Perseverance rover is equipped with a next-generation engineering camera imaging system that represents an upgrade over previous Mars rover missions. These upgrades will improve the operational capabilities of the rover with an emphasis on drive planning, robotic arm operation, instrument operations, sample caching activities, and documentation of key events during entry, descent, and landing (EDL). There are a total of 16 cameras in the Perseverance engineering imaging system, including 9 cameras for surface operations and 7 cameras for EDL documentation. There are 3 types of cameras designed for surface operations: Navigation cameras (Navcams, quantity 2), Hazard Avoidance Cameras (Hazcams, quantity 6), and Cachecam (quantity 1). The Navcams will acquire color stereo images of the surface with a 96 ∘ × 73 ∘ field of view at 0.33 mrad/pixel. The Hazcams will acquire color stereo images of the surface with a 136 ∘ × 102 ∘ at 0.46 mrad/pixel. The Cachecam, a new camera type, will acquire images of Martian material inside the sample tubes during caching operations at a spatial scale of 12.5 microns/pixel. There are 5 types of EDL documentation cameras: The Parachute Uplook Cameras (PUCs, quantity 3), the Descent stage Downlook Camera (DDC, quantity 1), the Rover Uplook Camera (RUC, quantity 1), the Rover Descent Camera (RDC, quantity 1), and the Lander Vision System (LVS) Camera (LCAM, quantity 1). The PUCs are mounted on the parachute support structure and will acquire video of the parachute deployment event as part of a system to characterize parachute performance. The DDC is attached to the descent stage and pointed downward, it will characterize vehicle dynamics by capturing video of the rover as it descends from the skycrane. The rover-mounted RUC, attached to the rover and looking upward, will capture similar video of the skycrane from the vantage point of the rover and will also acquire video of the descent stage flyaway event. The RDC, attached to the rover and looking downward, will document plume dynamics by imaging the Martian surface before, during, and after rover touchdown. The LCAM, mounted to the bottom of the rover chassis and pointed downward, will acquire 90 ∘ × 90 ∘ FOV images during the parachute descent phase of EDL as input to an onboard map localization by the Lander Vision System (LVS). The rover also carries a microphone, mounted externally on the rover chassis, to capture acoustic signatures during and after EDL. The Perseverance rover launched from Earth on July 30th, 2020, and touchdown on Mars is scheduled for February 18th, 2021.

A novel cardiac signal processing system for electrophysiology procedures: early insights from the pure ep 2.0 study

Background

Intracardiac electrogram data remain one of the primary diagnostic inputs guiding complex ablation procedures. However, the technology to collect, process, and display intracardiac signals has remained relatively unchanged for the past two decades.

Purpose

We test a new platform, the PURE EP™ 2.0 system (PEP; BioSig Technologies) for signal processing and display.

Methods

Identical electrocardiographic and intracardiac signal data were recorded during 15 AF ablation procedures from the PEP system, the signal recording system, and the 3D mapping system (Figure). The collected signals underwent blinded, controlled evaluation by three independent electrophysiologist reviewers to determine whether the PEP signals are a viable alternative to conventional sources and if it provides additional or clearer diagnostic information. Reviewers were asked to record the quality of each signal sample on a scale of 1–10 and select a rationale for their rating in a dropdown menu. Each paired signal rating was collected and unblinded for the analysis. If the reviewer rated the samples in the set within 1 point of each other, the PEP sample was deemed equivalent to the control. Using a 2+1 statistical method, the ratings from the three reviewers were then compared looking for at least two positive reviews for each PEP sample.

Results

Based on the ratings for each pair of signals, a cumulative total of 29 PEP signals out of 34 (85.3%) were rated as statistically equivalent or better for this dataset. In 35.5% of samples, the reviewers selected PEP because “more signal components were visible”.

Conclusion

The PURE EP 2.0 system is able to produce reliable and high-quality signals when compared to available standard of care systems. Further studies with larger dataset across multiple sites are needed to validate these results.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): BioSig Technologies

Prioritising physical and psychological symptoms: what are the barriers and facilitators to the discussion of anxiety in the primary care consultation?

Background

Anxiety is under-recorded and under-treated in the UK and is under-represented in research compared with depression. Detecting anxiety can be difficult because of co-existing conditions. GPs can be reluctant to medicalise anxiety symptoms and patients can be reluctant to disclose them, for a variety of reasons. This research addresses the gap in evidence of real-life consultations of patients with anxiety and explores how physical and psychological symptoms are discussed and prioritised by patients and GPs in primary care consultations.

Methods

A mixed methods study using a baseline questionnaire, video-recorded primary care consultations and interview data with patients and GPs.

Results

Seventeen patients with anxiety symptoms (GAD-7 score ≥ 10) completed a questionnaire, had their consultation video-recorded and took part in a semi-structured interview. Four GPs were interviewed. The main themes that emerged from GP and patients accounts as barriers and facilitators to discussing anxiety mostly mirrored each other. The GP/patient relationship and continuity of care was the main facilitator for the discussion of anxiety in the consultation. The main barriers were: attribution of or unacknowledged symptoms; co-morbidities; and time constraints. GPs overcame these barriers by making repeat appointments and employing prioritising techniques; patients by choosing an empathetic GP.

Conclusions

The findings add to the evidence base concerning the management of anxiety in primary care. The findings suggest that the discussion around anxiety is a process negotiated between the patient and the GP influenced by a range of barriers and facilitators. Co-existing depression and health anxieties can mask anxiety symptoms in patients. Good practice techniques such as bringing back patients for appointments to foster continuity of care and understanding can help disclosure and detection of anxiety symptoms. Future research could investigate this longitudinally and should include a wider range of GPs practices and GPs.

Electronic supplementary material

The online version of this article (10.1186/s12875-019-0996-6) contains supplementary material, which is available to authorized users.

Nuclear Magnetic Shielding and Quadrupole Coupling of 133Cs in Cesium Salt Powders

NMR signals of 133Cs have been measured in CsI, CsBr, CsCl, Cs2CO3, Cs2SO4, CsNO3 and Cs2CrO4 powders relative to a 0.5 molal aqueous solution of CsCl. Combining these results with the shielding constant of the solution, which has been determined in former measurements, the nuclear magnetic shielding of 133Cs in the crystalline powders can be given in an atomic reference scale. The theoretical values of the shielding constant of 133Cs in CsCl, CsBr and Csl agree only in the order of magnitude with the experimental ones. For 133Cs in Cs2SO4 a first-order quadrupole pattern has been observed.

NMR Spectra of Alkali and Halogen Nuclei in Alkali and Halogen Salts

NMR signals of 7Li, 23Na, 35Cl, 39K, 79Br, 87Rb and 127I have been measured in various alkali and halogen salt powders relative to well defined aqueous solutions. With the known shielding constants of some of these solutions the nuclear magnetic shielding constants of the alkali and chlorine nuclei in crystalline powders were evaluated in the atomic reference scale. The theoretical values of the shielding constants in alkali halides do not agree even in the order of magnitude with the experimental ones in some cases.

For 23Na first-order and second-order quadrupole patterns have been observed and the quadrupole coupling constants are given.

Investigation of thyroid dysfunction is more likely in patients with high psychological morbidity

BACKGROUND

Mild or subclinical hypothyroidism [raised thyroid-stimulating hormone (TSH) but normal free thyroxine (T4)] affects 5-10% of adults. Symptoms are non-specific and TSH levels are needed for diagnosis.

OBJECTIVES

We explore the relationship between thyroid function and psychological distress and investigate the usefulness of an expert-designed Thyroid Symptom Questionnaire (TSQ) in identifying hypothyroidism.

METHODS

DEPTH (DEPression and THyroid) is a cross-sectional study of 325 patients recruited from general practices in Bristol, for whom thyroid function tests were requested by the GP. Subjects completed the TSQ, General Health Questionnaire (GHQ-12) and Patient Health Questionnaire (PHQ) and had blood tests for TSH and free T4.

RESULTS

The mean age was 45.7 years; 252 subjects (78%) were female; median TSH was 1.6. Psychological morbidity in this population is high: 54.2% have a GHQ-12 score >3, indicating psychological distress. We found no relationship between TSH and psychological distress [adjusted odds ratio 1.02 (95% confidence interval 0.91-1.13), P = 0.78]. The prevalence of hypothyroidism was 6.2% (95% confidence interval 3.8-9.5%). We found no evidence of an unadjusted association between TSQ score and subclinical hypothyroidism [adjusted odds ratio of 1.09 (95% confidence interval 0.95-1.24), P = 0.23].

CONCLUSIONS

Those referred for thyroid function tests, although no more likely than others to have hypothyroidism, have high rates of psychological distress. When mild (subclinical) hypothyroidism is detected in patients with psychological distress, it is important that GPs are aware that this is likely to be coincidental rather than causal and offer appropriate treatment.

[Vocational interventions integrated in inpatient rehabilitation]

Orientation on work place associated problems is a typical assignment of medical rehabilitation in Germany. The implementation of special vocational programmes, however, may be associated with several challenges concerning staff and space required, which could be difficult to overcome.

No clear evidence of an association between plasma concentrations of n-3 long-chain polyunsaturated fatty acids and depressed mood in a non-clinical population

Previous research suggests that low n-3 long-chain polyunsaturated fatty acid (n-3PUFA) status is associated with higher levels of depression in clinical populations. This analysis aimed to investigate the relationship between depressed mood and n-3PUFA status in a non-clinical population. The analysis was conducted on data collected as part of a large randomized controlled trial investigating the impact of n-3PUFA supplementation on depressed mood in a community-based population. On entry into the trial, data on depressed mood were collected using the Depression, Anxiety and Stress Scales (DASS) and the Beck Depression Inventory (BDI). Plasma concentrations of various n-3PUFAs and n-6 long-chain polyunsaturated fatty acids (n-6PUFAs) were obtained from fasting venous blood samples, and various demographics were also measured. Using regression, there was no evidence of an association between either measure of depressed mood and any of the measures of n-3PUFA status or of n-6PUFA:n-3PUFA ratios. Clear associations were also not found when demographic factors were included in the analyses. These findings suggest that n-3PUFAs may not have a role in the aetiology of minor depression. This is also consistent with the results of other studies that have not demonstrated an association between depressed mood and n-3PUFA status in non-clinical populations and epidemiological studies that have not demonstrated an association between depressed mood and n-3PUFA intake in these populations.

Assessing mental health in primary care research using standardized scales: can it be carried out over the telephone?

BACKGROUND

Telephone interviewing has economic and logistical advantages but has not been widely used in the UK. Most studies comparing face-to-face and telephone psychiatric assessment have been carried out in the US, often restricted to a population with known psychiatric disorder and involving comparisons between two separate sample groups rather than repeat interviews with the same group. The aim of the present study was to compare face-to-face and telephone administration of the 12-item General Health Questionnaire and the Revised Clinical Interview Schedule in a UK general practice sample.

METHOD

Ninety-eight consecutive attenders at two general practices were assessed twice within 48 h. The order of face-to-face and telephone interviews was alternated.

RESULTS

There was no evidence that the mode of administration led to a bias in scores on the CIS-R. For the GHQ, those aged over 60 tended to score higher on the telephone. There was good agreement between face-to-face and telephone scores for both GHQ and CIS-R and good agreement for case definition. Participants had a strong preference for face-to-face interviews.

CONCLUSIONS

Telephone assessment of mental health using the GHQ and CIS-R is a reasonable method to be used in primary care research in the UK with the limitation that telephone responses from older people might be different from face-to-face assessments for the GHQ. However, telephone interviewing appeared less acceptable and should probably be used in the context of established or ongoing personal contact between researcher and subject.

Fibroblasts in mechanically stressed collagen lattices assume a "synthetic" phenotype

Fibroblasts are subjected to changes of the mechanical force balance during physiological as well as pathological situations, such as wound healing, development of hypertrophic scars, and fibrogenesis. However, the molecular response and the changes in fibroblast gene expression upon mechanical stimulation remain poorly understood. As an in vitro model, human dermal fibroblasts were cultured within a three-dimensional network of fibrillar collagen either under high (stressed) or low tension (relaxed). cDNA microarray technology in combination with Northern blot analysis led to identification of mechano-responsive genes coding for extracellular matrix proteins, fibrogenic growth factors, protease inhibitors, components of focal adhesions, and the cytoskeleton. Application of biaxial strain to fibroblasts cultured on flexible silicone membranes revealed that the type of strain as well as the properties of the substrate induced different patterns of gene regulation. The transcriptional profile of mechanically induced genes in collagen lattices suggests that mechanical stimuli lead to a "synthetic" fibroblast phenotype characterized by induction of connective tissue synthesis while simultaneously inhibiting matrix degradation.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy

Arrhythmogenic right ventricular dysplasia (ARVD/C) is one cause of death in young adults in the United States, representing approximately 17% of all ARVD/C cases reported. This study presents 2 cases of ARVD/C diagnosed at a central Texas hospital and reviews the literature regarding this disease. The diagnosis, histology, presentation, prognosis, and therapy are addressed because the rare nature of this disease within the United States makes diagnosis and treatment difficult and creates problems of adaptation for the patient. Clinicians must become more familiar with this potentially fatal cardiac disorder that can create vulnerability within a young adult population.

Surveillance of HIV-1 genetic subtypesand diversity in the US blood supply

BACKGROUND

Recent reports of variant (non-subtype B) HIV infections in US populations have raised concerns about the sensitivity of subtype B virus-based donor screening and diagnostic assays. This study was designed to determine the prevalence and genetic diversity of HIV subtypes in US blood donors over the last two decades.

STUDY DESIGN AND METHODS

Three groups were studied: hemophiliacs infected by clotting factor concentrates in the early 1980s (n = 49), blood donors retrospectively identified as being seropositive in 1985 (n = 97), and blood donors identified as seropositive between 1993 and 1996 (n = 405). Subtype assignment was based primarily on heteroduplex mobility analysis (HMA) of HIV-1 env, with DNA sequence confirmation of selected specimens. HIV peptide-based EIA serotyping was used to rule out HIV-2 and group O infections and to serotype HMA-refractory specimens.

RESULTS

Of 551 specimens, 535 (97%) were assigned subtypes; 532 (99%) of these were subtype B. Three postscreening donations (1%) were assigned non-B subtypes (2 A, 1 C). Two of these three donors were born in Africa; the third was born in the United States and reported no risk factors other than heterosexual activity. HMA distribution plots showed an increase in env diversity among HIV-1 group B strains over time.

CONCLUSION

The results support the need for continued surveillance of HIV subtype diversity and ongoing validation of the sensitivity of HIV diagnostic assays to non-B subtype infections.

Fibroblast-matrix interactions in wound healing and fibrosis

The regulation of matrix deposition is a key event in many physiological and pathological situations. It involves the activity of mediators in autocrine and paracrine fashions and the contact of cells with the surrounding extracellular matrix as well. The tightly regulated balance of both mechanisms guarantees rapid and adaptive cellular responses to meet changes in the biological requirements of the environment. Disturbances lead to wound healing defects or the development of fibrosis. The molecular mechanisms for these regulatory events are only partially understood, but involve the activity of integrins and a structural continuum of extracellular matrix-receptor-cytoskeleton-nucleus for transfer of information and the regulation of activated genes.

Crystal structure of the cystine C-S lyase from Synechocystis: stabilization of cysteine persulfide for FeS cluster biosynthesis

FeS clusters are versatile cofactors of a variety of proteins, but the mechanisms of their biosynthesis are still unknown. The cystine C-S lyase from Synechocystis has been identified as a participant in ferredoxin FeS cluster formation. Herein, we report on the crystal structure of the lyase and of a complex with the reaction products of cystine cleavage at 1.8- and 1.55-A resolution, respectively. The sulfur-containing product was unequivocally identified as cysteine persulfide. The reactive persulfide group is fixed by a hydrogen bond to His-114 in the center of a hydrophobic pocket and is thereby shielded from the solvent. Binding and stabilization of the cysteine persulfide represent an alternative to the generation of a protein-bound persulfide by NifS-like proteins and point to the general importance of persulfidic compounds for FeS cluster assembly.

Sexual motives, gender, and sexual behavior

The roles of gender and the sexual motives of Love, Pleasure, Conformity, Recognition, Dominance, and Submission in numerous usual and unusual sexual behaviors were investigated. In a survey of 191 college undergraduates it was found that Love, Pleasure, Conformity, and Recognition motives, often in interaction with gender, were all important predictors of sexual behavior. Gender was the best predictor of initiating usual sexual behavior, whereas the Love motive was the best predictor of actually engaging in usual sexual behavior. Pleasure and Recognition in interaction with gender were the best predictors of engaging in unusual sexual behavior. None of the sexual motives predicted initiating unusual sexual behavior. Findings suggest that a variety of sexual motives may underlie sexual behavior.

Formulation development and antitumor activity of a filter-sterilizable emulsion of paclitaxel

PURPOSE

Paclitaxel is currently administered i.v. as a slow infusion of a solution of the drug in an ethanol:surfactant:saline admixture. However, poor solubilization and toxicity are associated with this drug therapy. Alternative drug delivery systems, including parenteral emulsions, are under development in recent years to reduce drug toxicity, improve efficacy and eliminate premedication.

METHODS

Paclitaxel emulsions were prepared by high-shear homogenization. The particle size of the emulsions was measured by dynamic light scattering. Drug concentration was quantified by HPLC and in vitro drug release was monitored by membrane dialysis. The physical stability of emulsions was monitored by particle size changes in both the mean droplet diameter and 99% cumulative distribution. Paclitaxel potency and changes in the concentration of known degradants were used as chemical stability indicators. Single dose acute toxicity studies were conducted in healthy mice and efficacy studies in B 16 melanoma tumor-bearing mice.

RESULTS

QW8184, a physically and chemically stable sub-micron oil-in-water (o/w) emulsion of paclitaxel, can be prepared at high drug loading (8-10 mg/mL) having a mean droplet diameter of <100 nm and 99% cumulative particle size distribution of <200 nm. In vitro release studies demonstrated low and sustained drug release both in the presence and absence of human serum albumin. Based on single dose acute toxicity studies, QW8184 is well tolerated both in mice and rats with about a 3-fold increase in the maximum-tolerated-dose (MTD) over the current marketed drug formulation. Using the B16 mouse melanoma model, a significant improvement in drug efficacy was observed with QW8184 over Taxol.

CONCLUSIONS

QW8184, a stable sub-micron o/w emulsion of paclitaxel has been developed that can be filter-sterilized and administered i.v. as a bolus dose. When compared to Taxol, this emulsion exhibited reduced toxicity and improved efficacy most likely due to the composition and dependent physicochemical characteristics of the emulsion.

Multivessel coronary artery bypass surgery without cardiopulmonary bypass

BACKGROUND

There is limited experience with complete myocardial revascularization on a beating heart. Using a mechanical stabilization system, we sought to determine if complete coronary revascularization is feasible without cardiopulmonary bypass and what the short-term clinical outcome would be.

METHODS

From February through September 1998, 26 patients underwent complete myocardial revascularization with Medtronics Octopus Tissue Stabilization System. Mean age for the group was 62 +/- 7 years (range 48 to 78 years); 11% had prior interventions. Mean preoperative ejection fraction was 49% +/- 14% (range 20% to 66%); 38% of operations were performed urgently. The mean number of vessels grafted was 3.0 +/- 0.9 (range 1 to 5 grafts/patient). In 96% of patients, at least one arterial graft was used. Fifteen percent of patients had 2 or more arterial grafts. In 58% of patients, a branch of circumflex coronary artery was bypassed.

RESULTS

The median time to extubation was 2 hours (range 0 to 37 hours). None of the patients had perioperative myocardial infarction, cerebrovascular accident, or renal failure requiring dialysis. The 30-day survival rate was 100%. Angiographic follow-up was not available. At a mean follow-up period of 3.8 +/- 2.9 months, all patients remained free of angina and none has required cardiac reintervention.

CONCLUSIONS

Complete myocardial revascularization on a beating heart can be achieved with the currently available stabilization systems and is associated with low perioperative complications and satisfactory short-term clinical outcomes. The long-term outcomes and graft patency remain to be determined.

[Parallel use of medical services? Patterns of using complementary medicine and biomedicine]

In order to identify behavioural patterns within the pluralistic medical system, 38 patients have been observed over a period of two years. The most notable quality of behaviour is its flexibility. Single patients use complementary medicine and biomedicine in pragmatic and differentiated ways that change over time. Parallelism can be observed among the offered medical services, while their use is to be divided into parallel, alternate, alternative and complementary forms. Phases of exclusive use of complementary medicine occur, but during the two year period under investigation, all patients have made use of biomedicine.

Antiplatelet therapy: glycoprotein IIb/IIIa receptor antagonists

The glycoprotein IIb/IIIa antagonists are potent drugs that inhibit platelet aggregation. They are formulated as monoclonal antibodies and synthetic peptides for intravenous use in patients undergoing high-risk angioplasty procedures and in patients with unstable coronary syndromes. Orally active agents are now being evaluated in clinical trials.

Cross sectional study of symptom attribution and recognition of depression and anxiety in primary care

OBJECTIVES

To examine the effect of patients' causal attributions of common somatic symptoms on recognition by general practitioners of cases of depression and anxiety and to test the hypothesis that normalising attributions make recognition less likely.

DESIGN

Cross sectional survey.

SETTING

One general practice of eight doctors in Bristol.

SUBJECTS

305 general practice attenders.

MAIN OUTCOME MEASURE

The rate of detection by general practitioners of cases of depression and anxiety as defined by the general health questionnaire.

RESULTS

Consecutive attenders completed the general health questionnaire and the symptom interpretation questionnaire, which scores style of symptom attribution along the dimensions of psychologising, somatising, and normalising. General practitioners detected depression or anxiety in 56 (36%; 95% confidence interval 28% to 44%) of the 157 patients who scored highly on the general health questionnaire. Subjects with a normalising attributional style were less likely to be detected as cases; doctors did not make any psychological diagnosis in 46 (85%; 73% to 93%) of 54 patients who had high questionnaire and high normalising scores. Those with a psychologising style were more likely to be detected; doctors did not detect 21 (38%; 25% to 52%) of 55 patients who had high questionnaire and high psychologising scores. The somatisation scale was not associated with low detection rates. This pattern of results persisted after adjustment for age, sex, general health questionnaire score, and general practitioner.

CONCLUSIONS

Normalising attributions minimise symptoms and are non-pathological in character. The normalising attributional style is predominant in general practice attenders and is an important cause of low rates of detection of depression and anxiety.

Evidence for cysteine persulfide as reaction product of L-Cyst(e)ine C-S-lyase (C-DES) from Synechocystis. Analyses using cystine analogues and recombinant C-DES

The pyridoxal phosphate-dependent monomeric L-cysteine/cystine C-S-lyase (C-DES), previously isolated from Synechocystis PCC 6714 by its capacity to direct [2Fe-2S] cluster assembly of ferredoxin in vitro (Leibrecht, I., and Kessler, D. (1997) J. Biol. Chem. 272, 10442-10447), has now been cloned, sequenced, and overexpressed in Escherichia coli. The amino acid sequence of C-DES was found to be nearly identical (92% identity) to the open reading frame slr2143 of Synechocystis PCC 6803 and showed a more distant relationship to the NifS family of proteins (about 27% identity). Recombinant C-DES displayed activities equal to the isolate from Synechocystis in terms of the cyst(e)ine lyase reaction and holoferredoxin formation which recommended its use for functional and mechanistic studies. Investigation of the substrate spectrum for beta-elimination found L-cysteine to be a poor substrate (kcat approximately 0.15 s-1) in contrast to L-cystine (kcat = 36 s-1) and several related compounds. Of these compounds, desaminocystine (S-(carboxyethylthio)-L-cysteine) was used for C-DES-mediated persulfide generation. Stabilization of the linear persulfide 3-(disulfanyl)-propionic acid was achieved by cyclization as a novel intramolecular trapping reaction; this yielded 1,2-dithiolan-3-one which was isolated and identified by chemical analyses.

Interactions of fibroblasts with the extracellular matrix: implications for the understanding of fibrosis

The cellular organization and the compartmentalization in multicellular organisms is mediated by the extracellular matrix (ECM). This structure is composed by a wide variety of different macromolecules which carry distinct domains with defined structural and/or biological activities. Cells are known to interact with these molecules via specific receptors. Following activation, these receptors transduce signals either directly to the intracellular cytoskeleton or via different signalling cascades. Cell-matrix interactions, therefore, not only control the shape and orientation of cells but can also directly regulate cellular functions, including migration, differentiation, proliferation, and the expression of different genes. These cell-matrix interactions have been elucidated in detail for several biological processes, especially morphogenesis and differentiation, but also play an important role during pathological situations, e.g. wound healing and tumor progression. Although much less investigated, similar mechanisms are thought to regulate the biological behavior of fibroblastic cells, the final target cells in fibrosis. The activity of these cells depends in various ways on the presence of ECM molecules. First, some of the molecules are known to bind to and modulate the activity of those growth factors and cytokines, which lead to the activation of fibroblasts during the early phases of fibrosis. Second, deposition of large amounts of ECM molecules alters the environment and the mechanical load on the cells which are embedded in this matrix. Third, ECM molecules directly modulate fibroblast metabolism via certain integrin receptors. This review summarizes recent developments in all three domains. It mainly focuses on the direct role of ECM molecules in the biosynthetic activity of fibroblasts.

Conventional and hypobaric activation of an ultrasound contrast agent

Hypobaric activation is a new injection technique for use with the contrast agent EchoGen and, in this study, the agent's ability to produce parenchymal enhancement in vivo, with and without prior hypobaric activation, was investigated. Injections, ranging in dose from 0.05 to 0.5 mL/kg, were administrated through a peripheral vein to eight woodchucks with multiple hepatomas. At the 0.10 mL/kg dose level, seven of eight injections following hypobaric activation (88%) resulted in definite parenchymal enhancement. Conversely, dosages of 0.10 mL/kg without prior hypobaric activation produced no grey-scale changes. Only at the 0.4 and 0.5 mL/kg dosage level did the conventional administration technique obtain similar results (4 of 5 injections increased the echogenicity for a 0.4 mL/kg dose). These differences were statistically significant (p = 0.031). In vitro experiments were conducted to establish the physical mechanisms behind hypobaric activation. Relative measurements of contrast microbubble sizes were performed with a phase Doppler particle analyzer after hypobaric and after conventional (bolus) activation. Hypobaric activation produced approximately 20 times more microbubbles per unit volume than the conventional method. In conclusion, this investigation has demonstrated the benefits of prior hypobaric activation when performing in vivo contrast studies with EchoGen and determined the physical mechanisms behind this new injection technique. Hypobaric activation of EchoGen increases contrast enhancement and reduces dose size.

Effect of 50 milliliters of 50% dextrose in water administration on the blood sugar of euglycemic volunteers

OBJECTIVE

To evaluate the effect of administration of 1 ampule of 50% dextrose in water solution (D50W) on serum glucose levels in healthy adult volunteers, the authors set out to determine whether a pre-D50W serum glucose level can be predicted from the ED sample.

METHODS

This was a prospective, interventional study conducted from the ED of an urban, university-affiliated hospital. All subjects were healthy employee volunteers between 25 and 40 years of age. Baseline serum glucose levels were determined and all subjects were given an i.v. bolus of 25 grams of 50% dextrose solution. The main outcome measures were post-D50W serum glucose levels (observed) at 5 predetermined time intervals (5 min, 15 min, 30 min, 1 hr, and 2 hr). An expected change in serum glucose was calculated using the volume of distribution formula for glucose.

RESULTS

Twenty-five volunteers (17 males and 8 females) participated in the study. The mean baseline serum glucose was 82.3 +/- 13.5 mg/dL. The mean post-infusion levels were: 244.4 +/- 44.6 mg/dL (5 min), 145.8 +/- 52.3 mg/dL (15 min), 88.1 +/- 28.8 mg/dL (30 min), 77.6 +/- 13.6 mg/dL (60 min), and 83.2 +/- 11.4 mg/dL (120 min). Using a mixed-effect regression model, statistically significant increases in serum glucose levels were found at 5 minutes (p < 0.001) and 15 minutes (p < 00001) following administration of D50W. There was a return to baseline serum glucose by 30 minutes. The expected change based on the volume of distribution formula (53.7 +/- 34.9) did not correlate with the observed changes at any measured time interval.

CONCLUSION

Without pre-intervention blood drawing by emergency medical services, it is not possible to accurately predict pre-D50W serum glucose levels based on post-D50W glucose levels. The diagnosis of hypoglycemia as the etiology of altered mental status must therefore remain a diagnosis of exclusion. In addition, the return of serum glucose to baseline after 30 minutes suggests the duration of the effect of 1 ampule of D50W. Frequent re-evaluation of the serum glucose levels of suspected or proven hypoglycemic patients after administration of D50W should be considered.

Convenience store robberies in selected metropolitan areas. Risk factors for employee injury

Circumstances of injury were abstracted from police reports for 1835 convenience store robberies that occurred during 1992 or 1993 in selected metropolitan areas of seven eastern states. Subset analyses were performed using the data (758 robberies) from four states with relatively complete risk factor information. The purpose of this study was to estimate the risk of injury in a robbery situation for various risk factors. The overall risk of employee robbery-related injury could not be estimated because the probability of robbery is unknown. Of the 1835 robberies, 59% of the total robberies occurred at nighttime (9 p.m. to 3 a.m.), 47% occurred in stores previously robbed in the study period, 63% involved the use of a firearm, and 12% were associated with an injury to at least one employee. In the subset analysis of 758 robberies in four states, the employee probability of injury in a robbery was lower with firearm use compared with no weapon or use of a blunt instrument, and the probability of severe injury (defined as death, or an injury necessitating a trip to a hospital) was lower with a firearm compared with the use of a blunt instrument. However, all five fatalities were firearm-related. Other factors that were associated with a lower probability of employee injury included robbery occurrence in stores that had been robbed multiple times, compared with stores robbed only once; having 1 to 999 dollars stolen, compared with having no money stolen; and the presence of a customer(s) in the store at the time of the robbery. The employee risk of injury was not significantly different between one- (0.106) and multiple-employee (0.111) stores. Similarly, the employee risk of severe injury was not significantly different between one- (0.029) and multiple-employee stores (0.022). We conclude that there are several potential risk factors for employee injury in convenience store robberies, some of which are amenable to interventions. Further research on these factors and their relationship to employee injury is indicated.

A novel L-cysteine/cystine C-S-lyase directing [2Fe-2S] cluster formation of Synechocystis ferredoxin

Iron-sulfur proteins acquire their clusters by posttranslational assembly. To identify components involved in this process an in vitro assay for holoprotein formation was established using the [2Fe-2S] ferredoxin of the cyanobacterium Synechocystis as a model. Conversion of apoferredoxin to the holo- form was observed in an anaerobic reaction medium containing Fe(NH4)2(SO4)2, L-cysteine, glutathione, and catalytic amounts of Synechocystis extract, specifically depleted of endogeneous ferredoxin. An approximate 2500-fold purification of the converter activity yielded a monomeric, 43-kDa, pyridoxal phosphate-containing enzyme, which catalyzed the breakdown of L-cysteine to yield sulfide (assembled in ferredoxin), pyruvate, and ammonia; 1 mol of [2Fe-2S] ferredoxin was formed per 2 mol of cysteine utilized. The purified enzyme also catalyzed the beta-elimination reaction with cysteine in the absence of apoferredoxin. An increased reactivity was found with cystine instead of cysteine, which should yield cysteine persulfide as the primary product. These results provide a function-based identification of a cysteine/cystine C-S-lyase as a participant in ferredoxin Fe-S cluster formation. A substrate-derived cysteine persulfide could be involved in this reaction.