Cluster analysis demonstrates co-existing sites of fragility fracture and associated comorbidities

We undertook cluster analysis in 11,003 patients who had sustained ≥ 1 fragility fracture, to find associations between fracture sites and comorbidities. We identified three distinct groups of fracture sites and four clusters of fractures and comorbidities. Knowledge of factors associated with fracture sites will aid prophylaxis in at-risk patients.

INTRODUCTION

Fragility fracture (FF) prevalence is increasing. Subsequent fractures lead to greater morbidity and mortality. Few data are available on the association between FF sites and comorbidities.

OBJECTIVES

1. Establish the most common sites of FF and clusters within patients. 2. Identify patterns of co-existing FF and associated comorbidities.

METHODS

We retrospectively reviewed clinical records of patients undergoing bone mineral density estimation at a district hospital in North-West England, 2004-2016, identifying those who had sustained ≥ 1 FF. Demographics, FF site(s), comorbidities, and medications were recorded. Cluster analysis was performed on fracture sites alone, and sites and comorbidities, using Jaccard similarity coefficient. Results were plotted on a dendrogram and divided into clusters.

RESULTS

Of 28,868 patients, 11,003 had sustained ≥ 1 FF, 84.6% female, with overall mean age 67.5 years and median T-score - 1.12 SD. FF of the forearm was more frequent (n = 5045), most commonly co-existing with tibia/fibula fractures. Three FF site clusters were identified: ankle and elbow; forearm, tibia/fibula, ribs and spine; and pelvis, femur and humerus. When including comorbidities, four clusters were identified: forearm, tibia/fibula, spine, associated with family history of FF, smoking, corticosteroids and bisphosphonates; pelvis associated with hyperparathyroidism, PMR, coeliac disease and HRT; femur and humerus associated with IBD and RA; and ribs associated with alcohol and hyperthyroidism.

CONCLUSION

Cluster analysis demonstrated three fracture site clusters, and four subgroups of FF sites and comorbidities. Cluster analysis is a novel method to evaluate comorbidities associated with FF sites. Knowledge of factors associated with FF sites will aid prophylaxis in at-risk patients.

POS1179 SYSTEMATIC LITERATURE REVIEW ON THE SCREENING AND PROPHYLAXIS OF CHRONIC AND OPPORTUNISTIC INFECTIONS

Background

Opportunistic and chronic infections can arise in the context of treatment used for Autoimmune Rheumatic Diseases (ARDs). Although it is recognized that screening procedures and prophylactic measures must be followed, clinical practice is largely heterogeneous, with relevant recommendations not currently developed or disparately located across the literature.

Objectives

To conduct a systematic literature review (SLR) focusing on the screening and prophylaxis of opportunistic and chronic infections in ARDs. This is preparatory work done by members of the respective EULAR task force (TF).

Methods

Following the EULAR standardised operating procedures, we conducted an SLR with the following 5 search domains; 1) Infection: infectious agents identifed by a scoping review and expert opinion (TF members), 2) Rheumatic Diseases: all ARDs, 3) Immunosuppression: all immunosuppressives/immunomodulators used in rheumatology, 4) Screening: general and specific (e.g mantoux test) terms, 5) Prophylaxis: general and specific (e.g trimethoprim) terms. Articles were retrieved having the terms from domains 1 AND 2 AND 3, plus terms from domains 4 OR 5. Databases searched: Pubmed, Embase, Cochrane. Exclusion criteria: post-operative infections, pediatric ARDs, not ARDs (e.g septic arthritis), not concerning screening or prophylaxis, Covid-19 studies, articles concerning vaccinations and non-Εnglish literature. Quality of studies included was assessed as follows: Newcastle Ottawa scale for non-randomized controlled trials (RCTs), RoB-Cochrane tool for RCTs, AMSTAR2 for SLRs.

Results

5641 studies were initially retrieved (Figure 1). After title and abstract screening and removal of duplicates, 568 full-text articles were assessed for eligibility. Finally, 293 articles were included in the SLR. Most studies were of medium quality. Reasons for exclusion are shown in Figure 1. Results categorized as per type of microbe, are as follows: For Tuberculosis; evidence suggests that tuberculin skin test (TST) is affected by treatment with glucocorticoids and conventional synthetic DMARDs (csDMARDs) and its performance is inferior to interferon gamma release assay (IGRA). Agreement between TST and IGRA is moderate to low. Conversion of TST/IGRA occurs in about 10-15% of patients treated with biologic DMARDs (bDMARDs). Various prophylactic schemes have been used for latent TB, including isoniazide for 9 months, rifampicin for 4 months, isoniazide/rifampicin for 3-4 months. For hepatitis B (HBV): there is evidence that risk of reactivation is increased in patients positive for hepatitis B surface antigen. These patients should be referred for HBV treatment. Patients who are positive for anti-HBcore antibodies, are at low risk for reactivation when treated with glucocorticoids, cDMARDs and bDMARDs but should be monitored periodically with liver function tests and HBV-viral load. Patients treated with rituximab display higher risk for HBV reactivation especially when anti-HBs titers are low. Risk for reactivation in hepatitis C RNA positive patients, treated with bDMARDs is low. However, all patients should be referred for antiviral treatment and monitored periodically. For pneumocystis jirovecii: prophylaxis with trimethoprim/sulfamethoxazole (alternatively with atovaquone or pentamidine) should be considered in patients treated with prednisolone: 15-30mg/day for more than 4 weeks. Few data exist for screening and prophylaxis from viruses like EBV, CMV and Varicella Zoster Virus. Expert opinion supports the screening of rare bugs like histoplasma and trypanosoma in patients considered to be at high risk (e.g living in endemic areas).

Figure 1.

SLR flowchart

Conclusion

The risk of chronic and opportunistic infections should be considered in all patients prior to treatment with immunosuppressives/immunomodulators. Different screening and prophylaxis approaches are described in the literature, partly determined by individual patient and disease characteristics. Collaboration between different disciplines is important.

Acknowledgements

We would like to thank all members of the EULAR Task Force for the screening and prophylaxis of chronic and opportunistic infections in Autoimmune Rheumatic Diseases.

Disclosure of Interests

None declared

POS1461 GIANT CELL ARTERITIS-RELATED STROKE IN A MAN WITH ELDERLY-ONSET RHEUMATOID ARTHRITIS

Background

Giant cell arteritis-related stroke is rare, with high early mortality and major morbidity in survivors.

Objectives

To increase the awareness of coexistence of giant cell arteritis-related stroke and rheumatoid arthritis.

Methods

A case report and discussion.

Results

A 73 year-old man with seronegative elderly-onset rheumatoid arthritis (EORA) presented to the emergency department (ED) with a one week history of frontal headache, vomiting and dizziness. He had multiple cardiovascular comorbidities and took multiple medications, including methotrexate and sulfasalazine. He also had long-standing history of thrombocytopenia without requiring any treatment. Neurological examination performed in the ED was unremarkable. His C-reactive protein (CRP) was 69mg/L and erythrocyte sedimentation rate (ESR) 82mm/hour. Computed tomography (CT) of the brain was normal. The headache settled with analgesia. A diagnosis of probable tension-type headache, with underlying active EORA, was made.

One month later, he presented to an ophthalmologist with recurrence of headache associated with visual disturbance and was diagnosed with giant cell arteritis (GCA). Both CRP (77mg/L) and ESR (85mm/hour) remained raised. Neither temporal artery biopsy nor temporal artery ultrasound were possible due to the coronavirus disease 2019 (COVID-19) pandemic. The headache and visual symptoms resolved completely a week after prednisolone 60mg daily was prescribed. In parallel, the CRP dropped to 2mg/L and ESR 16mm/hour. The patient’s glucocorticoid dose was then tapered. While on prednisolone 20mg daily, about 3 weeks later, he developed slurred speech and generalized weakness. Examination showed cerebellar signs and MRI brain showed acute cerebellar infarct. He was treated pragmatically as an atherosclerotic stroke with clopidogrel, and the steroid was rapidly tapered in view of absence of headache and normalization of inflammatory markers.

Four weeks later, he was noted to have persistent confusion and unsteadiness of gait. CRP was elevated at 92mg/L. An urgent positron emission tomography-CT (PET-CT) scan showed inflammation in the vertebral arteries [Figure 1] and cerebellar stroke. Prednisolone 40mg daily was restarted which led to a rapid improvement in his symptoms and normalization of inflammatory markers. The glucocorticoids were tapered in a slower manner this time.

Figure 1.

Fused axial image of a PET-CT scan demonstrating increased uptake in the region of the left vertebral artery within the vertebral foramen.

A diagnosis of GCA-related cerebellar stroke with vertebral vasculitis was made and, with glucocorticoids, the patient made a good clinical recovery. His inflammatory joints pain also improved in parallel.

Conclusion

Stroke or transient ischemic stroke are rare complications, reported in 2.8-16% of patients with active GCA. Most studies report strokes as occurring between the onset of GCA symptoms and 4 weeks after commencement of glucocorticoids1-3.

Vertebrobasilar territory is involved in 60–88% of cases of GCA-related stroke1-3. In contrast, the vertebrobasilar territory is affected only in 15-20% of atherosclerotic strokes1,2. One study reported fatal outcomes in 11 out of 40 patients (28%) with GCA-related stroke, 7 within 2-13 days of stroke2.

To conclude, this case demonstrates that high-dose glucocorticoids with slower tapering were able to control GCA-related stroke due to vertebral vasculitis in patient with EORA on background methotrexate and sulfasalazine.

References

[1]Gonzalez-Gay MA, Vazquez-Rodriguez TR, Gomez-Acebo I, et al. Strokes at time of disease diagnosis in a series of 287 patients with biopsy-proven giant cell arteritis. Medicine. 2009;88(4):227-35.

[2]de Boysson H, Liozon E, Larivière D, et al. Giant cell arteritis–related stroke: a retrospective multicenter case-control study. 2017;44(3):297-303.

[3]Pariente A, Guédon A, Alamowitch S, et al. Ischemic stroke in giant-cell arteritis: French retrospective study. 2019;99:48.

Acknowledgements

We would like to thank Dr Lenetta Boyce for providing the PET-CT images.

Disclosure of Interests

None declared

Brain metastases: An update on the multi-disciplinary approach of clinical management

IMPORTANCE

Brain metastasis (BM) is the most common malignant intracranial neoplasm in adults with over 100,000 new cases annually in the United States and outnumbering primary brain tumors 10:1.

OBSERVATIONS

The incidence of BM in adult cancer patients ranges from 10-40%, and is increasing with improved surveillance, effective systemic therapy, and an aging population. The overall prognosis of cancer patients is largely dependent on the presence or absence of brain metastasis, and therefore, a timely and accurate diagnosis is crucial for improving long-term outcomes, especially in the current era of significantly improved systemic therapy for many common cancers. BM should be suspected in any cancer patient who develops new neurological deficits or behavioral abnormalities. Gadolinium enhanced MRI is the preferred imaging technique and BM must be distinguished from other pathologies. Large, symptomatic lesion(s) in patients with good functional status are best treated with surgery and stereotactic radiosurgery (SRS). Due to neurocognitive side effects and improved overall survival of cancer patients, whole brain radiotherapy (WBRT) is reserved as salvage therapy for patients with multiple lesions or as palliation. Newer approaches including multi-lesion stereotactic surgery, targeted therapy, and immunotherapy are also being investigated to improve outcomes while preserving quality of life.

CONCLUSION

With the significant advancements in the systemic treatment for cancer patients, addressing BM effectively is critical for overall survival. In addition to patient's performance status, therapeutic approach should be based on the type of primary tumor and associated molecular profile as well as the size, number, and location of metastatic lesion(s).

AB0649 INFECTION PROFILE OF IMMUNE-MODULATORY DRUGS USED IN AUTOIMMUNE DISEASES: ANALYSIS OF SUMMARY OF PRODUCT CHARACTERISTIC DATA

Background:

The number of immune-modulatory drugs used to treat immune-mediated inflammatory diseases (IMIDs) has exponentially increased in recent decades. While effective in controlling disease, serious infection remains a concern.

Accurate information on immune-modulatory drugs, including infections, is required to guide prescribing decisions. The “summary of product characteristics” (SmPC) by the European Medicines Agency (EMA) provides a useful repository of information on adverse events e.g. infections, from clinical trials and post-marketing pharmacovigilance (1).

To date, no comparison has been undertaken on reported infection frequencies across SmPCs for immune-modulators.

Objectives:

To compare infection frequency, site and type across the most commonly-prescribed immune-modulatory drugs used to treat IMIDs, using information provided by SmPCs.

Methods:

A drug was included if licensed in Europe for treatment of one of the following: rheumatoid arthritis, axial spondyloarthritis, connective tissue disease, autoimmune vasculitis, autoinflammatory syndromes, inflammatory bowel disease (Crohn’s and ulcerative colitis), psoriasis, multiple sclerosis and other rarer conditions.

The Electronic Medicines Compendium (EMC) was searched for commonly prescribed immune-modulatory drugs used for the above indications. SmPC documents were manually searched for information on infection frequency, extracted from sections 4.4 and 4.8. Infection frequency was recorded as per convention in the SmPC: very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000) (1), for each drug. Information was further extracted on infection site (e.g. respiratory, skin etc), type (e.g. bacterial, viral etc) and individual pathogenic organisms.

25% of included SmPCs were screened and extracted by a second reviewer. Disagreements were resolved with input from a third reviewer.

Results:

In total, 39 drugs were included, used across 20 indications: nine conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), six targeted synthetic DMARDs (tsDMARDs; four Janus kinase [JAK] inhibitors, two sphingosine 1-phosphate receptor modulators) and 24 biologic DMARDs (17 cytokine-targeted; seven cell-targeted).

Twelve sites of infection were recorded. Minimal or no site information was available for most csDMARDs and siponimod, certolizumab pegol and rituximab. The most common sites of infection are listed by drug group in Figure 1. Upper respiratory tract was the most common site, especially with bDMARDs. Lower respiratory, ear/nose/throat (including sinusitis) and urinary tract infections were moderately common, with clustering within drug groups. No drugs reported risk of cardiac infections; the eye, musculoskeletal, neurological, oral and reproductive sites were the least commonly-reported sites of infection.

Infection data for 27 distinct pathogens were recorded, the majority viruses, especially with bDMARD use. Herpes simplex and zoster were the most frequently listed (mainly with bDMARDs and tsDMARDs), followed by influenza. Common non-viral causes of infection were candida and tinea species.

Variable or absent reporting was noted for opportunistic infections (e.g. tuberculosis and fungi) and certain high-prevalence viruses e.g. Epstein-Barr.

Conclusion:

The SmPC literature reports differences in infection risk, by site and pathogen, between immune-modulatory drugs. The findings can be used to visualise differences and aid treatment decisions. However, some of the patterns we have shown lack face-validity to clinicians familiar with real-world safety data. The data fail to capture risk of rare infections, are likely skewed by trial selection criteria, varying number of trials per drug and quirks of individual study-reporting methodologies.

The findings highlight the need for robust post-marketing pharmacovigilance studies.

References:

[1]A Guideline on Summary of Product Characteristics Module 1.3. 2008.

Disclosure of Interests:

None declared.

OP0294 DIFFERENTIAL INFLUENCE OF CO-MORBIDITIES ON SITE OF FRAGILITY FRACTURES

Background:

Fragility fractures (FF) can occur at various sites of the skeleton, and are associated with multiple risk factors [1]. The prevalence of FF markedly increases with age. As the longevity of the population increases, so will the incidence of FF, and that of associated co-morbidities and risk factors. There are few data on co-morbidities associated with fractures at each site.

Objectives:

Identify associations of co-morbidities with sites of FF, by applying cluster analysis.

Methods:

We reviewed 28868 patients presenting for BMD estimation at a district general hospital in North West England, 2004-2016. We identified patients who had sustained one or more FF at time of presentation. Site(s) of FF were recorded for each patient, including femur, forearm, humerus, pelvis, ribs, spine, tibia or fibula. The following co-morbidities or treatments were recorded: excess alcohol consumption (previous or current); bisphosphonates; coeliac disease; family history of FF; hormone replacement therapy; hyperparathyroidism; hyperthyroidism; inflammatory bowel disease; polymyalgia rheumatica; rheumatoid arthritis; smoking (previous or current); corticosteroids (previous or current). Cluster analysis was performed on fracture sites and co-morbidities, using Jaccard similarity coefficient, and plotted on a dendrogram. Results were divided into an optimal number of clusters, derived using the elbow and silhouette methods.

Results:

11003 of 28868 patients had sustained one or more FF at time of BMD estimation. Overall, 84.6% patients were female, mean age 67.5years, and median T-score -1.12 SD. Cluster analysis was performed for FF sites and co-morbidities, with Jaccard similarity coefficients calculated. 4 clusters were identified (Figure 1): FF of forearm (n=5054), tibia/fibula (n=2617), spine (n=2352), associated with family history of FF, smoking, corticosteroids, and bisphosphonate treatment; FF of pelvis (n=300) associated with hyperparathyroidism, PMR, coeliac disease, and HRT; FF of femur (n=1181) and humerus (n=1131) associated with IBD and RA; FF of ribs (n=1022) associated with alcohol and hyperthyroidism.

Conclusion:

Cluster analysis demonstrated 4 distinct subgroups of FF sites and associated co-morbidities. To our knowledge, this is the first study applying cluster analysis to evaluate co-morbidities associated with FF sites. Risk factors may influence trabecular more than cortical bone, accounting for the difference in clusters. Knowledge of risk factors associated with FF site subgroups will aid prophylaxis and management in at-risk patients.

References:

[1]Kanis JA. Diagnosis of osteoporosis and assessment of fracture risk. Lancet (London, England). 2002 Jun 1;359(9321):1929–36

Disclosure of Interests:

Mrinalini Dey: None declared, Marwan Bukhari Speakers bureau: Bristol-Myers Squib, UCB celltech, Roche/Chugai, Pfizer, Abbvie, Merck, Mennarini, Sanofi-aventis, Eli-Lilly, Janssen, Amgen and Novartis.

OP0324 CLUSTERING OF FRAGILITY FRACTURES BY SITE IN PATIENTS REFERRED FOR BONE MINERAL DENSITY ESTIMATION: AN OBSERVATIONAL STUDY

Background:

Fragility fractures (FF) are those resulting from mechanical forces equivalent to a fall from standing height or less [1]. They most commonly occur in the spine (vertebrae), forearm, and femur, but also occur at other sites. Prevalence markedly increases with age, due to age-related and menopause-related bone loss. FF cause substantial pain and disability, and are associated with decreased life expectancy. While many studies have investigated risk factors associated with FF, there are few data on the association between FF sites in at-risk patients.

Objectives:

1. Establish the most common sites of FF in patients presenting for bone mineral density (BMD) estimation.

2. Identify patterns of co-existing FF in the above cohort by applying cluster analysis.

Methods:

We retrospectively reviewed the clinical records of 28868 patients presenting for BMD estimation at a district general hospital in North West England, 2004-2016, identifying those who had sustained one or more FF. Site(s) of FF were recorded for each patient, categorised as: ankle, elbow, femur, forearm, humerus, pelvis, ribs, spine, tibia or fibula (recorded as “tibfib”). Cluster analysis was performed on fracture sites, using Jaccard similarity coefficient. Results were plotted on a dendrogram and divided into clusters, as per results derived from elbow and silhouette cluster methods.

Results:

Out of 28868 patients presenting for BMD estimation, 11003 were identified as having sustained one or more FF. 84.6% patients were female, with overall mean age 67.5years and median T-score -1.12 SD. The most common site of FF was the forearm (n=5045), most commonly co-existing with fractures of the tibia or fibula. Frequencies of the most common and co-existing FF sites are shown in Figure 1 (top). Cluster analysis identified 3 clusters: ankle and elbow; forearm, tibia/fibula, ribs, and spine; pelvis, femur, and humerus. The second half of Figure 1 displays the dendrogram of cluster analysis results, with Jaccard similarity measure.

Conclusion:

We applied cluster analysis to a large cohort of patients presenting for BMD estimation. Our results are in keeping with previous studies demonstrating the FF to most commonly occur in the forearm, and in those with osteopenia (T-score -2.5 < -1 SD) [2]. To our knowledge, this is the first study to apply cluster analysis to sites of FF. Results may be due to differences in cortical and trabecular bone structure, and have potential to aid prevention, monitoring, and management in at-risk patients.

References:

[1]National Institute for Health and Care Excellence (NICE). Osteoporosis: assessing the risk of fragility fracture - Clinical Guideline (CG146). 2012;(August):1–14.

[2]Siris ES et al. Bone mineral density thresholds for pharmacological intervention to prevent fractures. Arch Intern Med. 2004 May 24;164(10):1108–12.

Disclosure of Interests:

Mrinalini Dey: None declared, Marwan Bukhari Speakers bureau: Bristol-Myers Squib, UCB celltech, Roche/Chugai, Pfizer, Abbvie, Merck, Mennarini, Sanofi-aventis, Eli-Lilly, Janssen, Amgen and Novartis.

AB0940 BIOMARKERS IN THE DIAGNOSIS OF ACUTE HOT JOINTS: AN EVALUATION OF RESEARCH INTEREST 1960-2018

Background:

The acute hot joint presentation is a common clinical emergency, often the result of crystal arthritis or trauma. However, all diagnoses can mimic septic arthritis, which should be excluded promptly due to the potential for rapid joint destruction and significant morbidity. The gold-standard test for septic arthritis is synovial fluid culture, which can take several days to perform. Meanwhile, patients are often admitted and given antimicrobials. Other specialties have made use of rapid biomarkers to exclude infection, for example, exclusion of empyema using pleural fluid pH and glucose [1]. Such biomarkers could reduce the need for lengthy hospital admissions and inappropriate antibiotic use in the acute hot joint presentation.

Objectives:

1.Evaluate research interest over time, on the use of diagnostic biomarkers in the acute hot joint presentation.

2.Compare research interest in the use of diagnostic biomarkers in acute hot native versus acute hot prosthetic joints.

Methods:

We performed a review of the number of publications reporting the use and diagnostic accuracy of biomarkers to exclude infection in the acute hot joint presentations. The database,Scopus, was searched for English-language studies (1946-2018) using search terms relating to septic arthritis, crystal arthritis, and diagnostic markers derived from synovial fluid/aspirate. The number of papers published per year on prosthetic joints only was also calculated. Therefore, the following were recorded for each year 1946-2018: total number of studies; prosthetic joints only; native joints only. Values were plotted, with polynomial trend-lines and R2calculated.

Results:

Our search yielded 2279 relevant studies in total (561 on prosthetic joints), published 1946-2018. Only 1 study was identified for the year 1946; the next recorded publication was in 1960. Therefore, this single study was excluded as an outlier. Results are presented in Figure 1. The number of studies on diagnostic biomarkers for acute hot joints continued to increase after 1960. From 2016, the number of studies conducted in prosthetic joints outnumbered those done in native joints. Polynomial trend-lines applied to the results showed studies on native acute hot joints are predicted to decline, while those in prosthetic joints will continue to increase.

Conclusion:

Reasons for an increasing number of studies on prosthetic compared to native acute hot joints include a narrower differential diagnosis in prosthetic joints, i.e. septic vs aseptic. In contrast, native acute hot joints may be the result of various causes including crystal arthritis, inflammatory arthritis, and trauma. Having a narrower differential diagnosis may facilitate diagnostic research in prosthetic joint presentations. Furthermore, incidence of prosthetic joint infection is also greater than that of native joint infection [2]. Nonetheless, the incidence of native joint infection is increasing [3]. This, and the lack of methods by which to rapidly distinguish native joint septic arthritis from non-infective causes, indicates that more research is required in this area.

References:

[1]Heffner JE et al. Pleural fluid chemical analysis in parapneumonic effusions. A meta-analysis. Am J Respir Crit Care Med. 1995 Jun;151(6):1700–8.

[2]Roerdink RL et al. The difference between native septic arthritis and prosthetic joint infections: A review of literature. J Orthop Surg (Hong Kong).

[3]Rutherford AI et al. A population study of the reported incidence of native joint septic arthritis in the United Kingdom between 1998 and 2013. Rheumatol (United Kingdom). 2016;55(12):2176–80.

Disclosure of Interests:

None declared

Psychiatric disorders, suicidality, and personality among young men by sexual orientation

Personality and its potential role in mediating risk of psychiatric disorders and suicidality are assessed by sexual orientation, using data collected among young Swiss men (n = 5875) recruited while presenting for mandatory military conscription. Mental health outcomes were analyzed by sexual attraction using logistic regression, controlling for five-factor model personality traits and socio-demographics. Homo/bisexual men demonstrated the highest scores for neuroticism-anxiety but the lowest for sociability and sensation seeking, with no differences for aggression-hostility. Among homo/bisexual men, 10.2% fulfilled diagnostic criteria for major depression in the past 2 weeks, 10.8% for ADHD in the past 12 months, 13.8% for lifetime anti-social personality disorder (ASPD), and 6.0% attempted suicide in the past 12 months. Upon adjusting (AOR) for personality traits, their odds ratios (OR) for major depression (OR = 4.78, 95% CI 2.81–8.14; AOR = 1.46, 95% CI 0.80–2.65) and ADHD (OR = 2.17, 95% CI = 1.31–3.58; AOR = 1.00, 95% CI 0.58–1.75) lost statistical significance, and the odds ratio for suicide attempt was halved (OR = 5.10, 95% CI 2.57–10.1; AOR = 2.42, 95% CI 1.16–5.02). There are noteworthy differences in personality traits by sexual orientation, and much of the increased mental morbidity appears to be accounted for by such underlying differences, with important implications for etiology and treatment.

Quality of life of parents of mentally-ill children: a systematic review and meta-analysis

AIMS

To examine the quality of life (QOL) of parents of children with a specific mental disorder (any age).

METHODS

Relevant articles were searched using different databases. Articles were included that compared the QOL of parents with mentally-ill children to parents of healthy controls or norm values or provided the required data for this comparison. A meta-analysis was conducted to obtain an overall mean effect size estimate. Additional analyses were performed to assess publication bias and moderation.

RESULTS

Twenty-six out of 10 548 articles met the pre-defined inclusion criteria. Most of these studies focused on attention-deficit/hyperactivity disorder or autism spectrum disorder, used clinical samples that mainly included males and young children and studied the QOL of mothers. The meta-analysis revealed that parents of mentally-ill children are experiencing a clinically relevant reduction in their QOL relative to parents of healthy children and norm values (g = -0.66).

CONCLUSIONS

The compromised QOL of parents of mentally-ill children needs to be considered and addressed by health professionals who are in contact with them. The paper provides insights into existing research gaps and suggests improvements for subsequent work.

Predictors of fracture risk in patients with systemic lupus erythematosus

Objectives Bone loss in systemic lupus erythematosus is multifactorial. Recent studies demonstrate corticosteroids, previous fractures and increasing age decrease bone mineral density. The effect of body mass index and fat mass are less well characterized. We sought to determine fracture risk factors in patients undergoing dual-energy X-ray absorptiometry scanning at a district hospital in 2004-2015. Methods Standard dual-energy X-ray absorptiometry parameters were recorded, plus rheumatoid arthritis diagnosis, smoking status, alcohol consumption, family history of fractures, history of secondary operation and corticosteroid use. Data were analyzed using Fisher's exact test for categorical data and logistic regression for continuous data. Results One hundred and fifty patients (141 women, nine men) with SLE were included; 52 (34.6%) had sustained at least one fracture. Fracture risk increased with increased age, body mass index, fat mass and average tissue thickness, and decreased lean mass (adjusted for steroid use), as well as with smoking and rheumatoid arthritis. Increased femoral and vertebral bone mineral density conversely decreased fracture risk. Conclusion Our study suggests increased age, body mass index, fat mass, smoking and/or rheumatoid arthritis increase fracture risk in SLE patients. To our knowledge, this is the first demonstration of a correlation between increased fat mass, adjusted for steroid use and fracture risk, in adults, potentially indicating a differential effect of fat on bone metabolism and lessening of lean body mass.

Postrenal transplant metastatic colonic neoplasm: Posttransplant lymphoproliferative disorder or adenocarcinoma?

Transplant recipients are vulnerable to a horde of infections and neoplastic conditions due to immunosuppression. Posttransplant lymphoproliferative disorder (PTLD) is a condition unique to the transplant recipient occurring due to monoclonal lymphocytic proliferation. It may affect any organ system with reportedly highest incidence in the gastrointestinal tract. The incidence of adenocarcinoma of the colon, however, has not been shown to be uniformly higher in transplant recipients. We report here an unusual case of adenocarcinoma of the ascending colon presenting with liver, lymph node and skin metastasis in a transplant recipient, which simulated PTLD both clinically and radiologically. For any gastrointestinal lesion in transplant recipient, the possibility of carcinoma must be considered. However, a high index of suspicion for PTLD facilitates early diagnosis since the treatment of the two conditions is starkly different.

Conversion of differentiated cancer cells into cancer stem-like cells in a glioblastoma model after primary chemotherapy

Glioblastoma multiforme patients have a poor prognosis due to therapeutic resistance and tumor relapse. It has been suggested that gliomas are driven by a rare subset of tumor cells known as glioma stem cells (GSCs). This hypothesis states that only a few GSCs are able to divide, differentiate, and initiate a new tumor. It has also been shown that this subpopulation is more resistant to conventional therapies than its differentiated counterpart. In order to understand glioma recurrence post therapy, we investigated the behavior of GSCs after primary chemotherapy. We first show that exposure of patient-derived as well as established glioma cell lines to therapeutic doses of temozolomide (TMZ), the most commonly used antiglioma chemotherapy, consistently increases the GSC pool over time both in vitro and in vivo. Secondly, lineage-tracing analysis of the expanded GSC pool suggests that such amplification is a result of a phenotypic shift in the non-GSC population to a GSC-like state in the presence of TMZ. The newly converted GSC population expresses markers associated with pluripotency and stemness, such as CD133, SOX2, Oct4, and Nestin. Furthermore, we show that intracranial implantation of the newly converted GSCs in nude mice results in a more efficient grafting and invasive phenotype. Taken together, these findings provide the first evidence that glioma cells exposed to chemotherapeutic agents are able to interconvert between non-GSCs and GSCs, thereby replenishing the original tumor population, leading to a more infiltrative phenotype and enhanced chemoresistance. This may represent a potential mechanism for therapeutic relapse.

Accommodation: its relation to refractive errors, amblyopia and biometric parameters

AIM

To study accommodation in relation to different refractive errors, amblyopia and to measure the anatomical changes in the accommodating eye

MATERIALS AND METHODS

We studied the amplitude of accommodation (AA) in 150 patients in the age group 11 ± 30 years which included emmetropes, myopes, hypermetropes and hypermetropic amblyopes using the Royal Air Force (RAF) rule. The anterior chamber depth (ACD), axial length (AxL) and lens thickness (LT) changes during accommodation were measured using an A-scan. Myopes and hypermetropes were further divided based on the amount of refractive error : less than 2D, 2 -4D and greater than 4D.

RESULTS

Corrected low myopes had the highest accommodation amplitude (p less than 0.05) followed by emmetropes. Corrected hypermetropes were found to have the lowest amplitude of accommodation (p less than 0.05). The amblyopic eye had a significantly low AA compared to the non-amblyopic eye (p less than 0.05). ACD decreased (p less than 0.05) and LT increased (p less than 0.05) during accommodation. The AxL increase was maximum in myopes (p less than 0.05) followed by hypermetropes but the change was not significant in hypermetropes (p greater than 0.05).

CONCLUSION

The amblyopic eye has low amplitudes of accommodation proving the benefit of near adds in amblyopic patients. Prolonged near work might induce myopia in susceptible eyes by increasing the axial length.

Presbyopia and its anatomical and physiological variants

AIM

To study the various ocular anatomical and physiological parameters in presbyopia.

MATERIALS AND METHODS

We studied the various ocular anatomical and physiological parameters like corneal curvature (keratometry readings: K1 and K2), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT) and axial length (AL) in 100 presbyopic patients between 35 - 55 years of age. The patients were divided into two age groups: I (35 ± 44 years) and II (45-55 yrs). ACD, AL and LT were measured using an Ascan. CCT was measured with ultrasonic pachymetry.

RESULTS

The CCT decreased (BE), LT increased and ACD decreased (RE) significantly with increasing age (p less than 0.05). There was no significant difference in males and females. Nearly 3/4th of the total increase in lens thickness was responsible for the decrease in the anterior chamber depth and the rest, 1/4th , goes posteriorly. Corneal curvature and AL showed no significant change with age.

CONCLUSIONS

The mean of CCT decreased significantly with advancing age. As age increased, the mean value of lens thickness increased and anterior chamber depth decreased. Nearly 3/4th of total increase in LT was anteriorly, decreasing the ACD. Corneal curvature and AL has no relation with age.

Bilateral exudative retinal detachment in a child with orbital pseudotumor

We describe a 15-year-old girl who presented with bilateral exudative retinal detachment, a previously unreported complication, due to orbital pseudotumor. She initially responded to steroids, but subsequently became steroid dependent. Azathioprine was effective in controlling further relapses during follow-up of 22 months.

Gametogenic responses of the testis in spotted munia (Lonchura punctulata; Aves) to oral administration of lithium chloride

In the present study, the effects of orally-administered lithium on testicular morphology were examined in the spotted munia (Lonchura punctulata), a seasonally breeding sub-tropical finch. Adult males were procured from natural populations during the month of August, a time when these birds begin to show seasonal reproductive maturity in an annual cycle. Both during the period of acclimation, and throughout the subsequent experimental period, the birds were maintained in an open aviary simulating natural environmental conditions. Lithium was dissolved in distilled water and was administered via the oral route by means of a commercially available stomach-tube. A total of five experimental groups were utilized. The first group (Group A) served as control and received lithium-free distilled water in a similar manner. In the remaining four groups, lithium was administered daily as follows: Group B (2.5 mEq/Kg body weight for 5 days); Group C (2.5 mEq/Kg for 10 days); Group D (5.0 mEq/Kg for 5 days) and Group E (5.0 mEq/Kg for 10 days). All lithium administrations were carried out between 14:00 and 15:00h. Twenty-four hours after the last oral lithium, final body weights were recorded, blood samples were obtained (by brachial vein puncture for the measurement of serum lithium) and the animals were sacrificed, and testes were collected for histological studies. Our results indicated that lithium treatment led to a significant reduction in testicular weight and seminiferous tubular diameter, and a marked degenerative changes in germ cells in that most of the spermatids and mature spermatozoa showed necrotic changes and were sloughed off from the seminiferous tubular epithelium. Complete desquamation and loss of germ cells, and their clump formation were also noted within many seminiferous tubular lumen. Notably these adverse effects were observed when serum lithium levels were within the therapeutic range for human. These results confirm our earlier report on lithium's adverse effects on testicular function, and extend further to show that lithium indeed has a significant adverse effect on the histomorphology, and, thus, the function of the testis in birds.

Isogenic strain of Escherichia coli O157:H7 that has lost both Shiga toxin 1 and 2 genes

An Escherichia coli O157:H7 strain isolated from a patient with hemorrhagic colitis was found to exhibit two slightly different colony morphology types on differential medium. Each morphological type, designated TT12A and TT12B, was isolated, and serological testing using various assays confirmed that both strains carried the O157 and the H7 antigens. Biochemical testing showed that the strains had identical profiles on AP120E analysis and, like typical O157:H7 strains, did not ferment sorbitol or exhibit beta-glucuronidase activity. Analysis with a multiplex PCR assay showed that TT12B did not carry the gene for either Shiga toxin 1 (Stx1) or Stx2, whereas these genes were present in TT12A and the toxins were produced. Apart from that, both strains carried the +93 gusA mutation, the cluster I ehxA gene for enterohemolysin, and the eae gene for gamma-intimin, which are all characteristics of the O157:H7 serotype. Phenotypic assays confirmed that both strains exhibited enterohemolysin activity and the attachment and effacing lesion on HeLa cells. Multilocus enzyme electrophoresis analysis showed that the strains are closely related genetically and belong in the same clonal group. Pulsed-field gel electrophoresis (PFGE) typing of XbaI-digested genomic DNA revealed that the two strains differed by two bands but shared 90% similarity and clustered in the same clade. All other non-Stx-producing O157:H7 strains examined clustered in a major clade that was distinct from that of Stx-producing O157:H7 strains. The findings that TT12B was identical to TT12A, except for Stx production, and its PFGE profile is also more closely related to that of Stx-producing O157:H7 strains suggest that TT12B was derived from TT12A by the loss of both stx genes.

Influences of graded dose of melatonin on the levels of blood glucose and adrenal catecholamines in male roseringed parakeets (Psittacula krameri ) under different photoperiods

Effects of daily evening (just before the onset of darkness in a 24 h light dark cycle) administration of graded doses (25, 50, or 100 microg/100 g body wt./day for 30 days) of melatonin on the concentrations of blood glucose and adrenal catecholamines were studied in sexually active male roseringed parakeets under natural (NP; approximately 12L: 12D) and artificial long (LP; 16L: 8D) and short (SP; 8L: 16D) photoperiods. Blood samples and adrenal glands were collected from each bird during the mid-day on the following day of the last treatment. The concentrations of glucose in blood and epinephrine (E) and norepinephrine (NE) in the adrenals were measured. The results of the study indicated that exogenous melatonin induces hypo- or hyperglycemia depending on the dose of hormone administered as well as to the length of photoperiod to which birds were exposed. The levels of E and NE in the adrenals were shown also to vary in relation to photoperiod and the dose of melatonin administered. But the nature of the influence of melatonin becomes different under altered photoperiodic conditions. It appears that short photoperiods are more effective than long photoperiods as a modulator of glycemic and adrenal catecholaminergic responses to exogenous melatonin. A statistically significant correlation between the levels of blood glucose and that of E and NE in the adrenals was found in the control birds, but not in the melatonin treated birds. The results suggested that the responses of blood glucose and adrenal catecholamines to the treatment with melatonin in the roseringed parakeets may not be dependent on each other.

Influence of photoperiods on glycemic and adrenal catecholaminergic responses to melatonin administrations in adult male roseringed parakeets, Psittacula krameri Neumann

Effects of daily (one hour prior to onset of darkness) injection of melatonin (25 micrograms/100 g body wt. for 30 days) on concentrations of blood glucose and adrenal catecholamines were studied in adult male roseringed parakeets, P. krameri under both natural (NP; about 12L:12D) and artificial long (LP; 16L:8D; lights were available in between 0600 and 2200 hrs) or short (SP; 8L:16D; lights were available between 0600 and 1400 hrs) photoperiodic conditions. The results indicate that neither LP, nor SP as such exerts any significant effect on blood glucose titre of control (vehicle of hormone administered) birds. Treatment with melatonin, however, induced hyperglycemia in both NP and LP bird groups, but hypoglycemia in SP birds. Unlike glycemic levels, amount of epinephrine (E) and norepinephrine (NE) in adrenals of control birds exhibited significant changes under altered photoperiods. A decrease in E and an increase in NE were noted in adrenals of both LP and SP birds. Exogenous melatonin in NP birds also caused a decrease in E and concomittant rise in NE levels. On the other hand, treatment of melatonin in both LP and SP bird groups resulted in an increase in the quantity of both E and NE compared to respective values in adrenals of melatonin injected NP birds. However, relative to the amount of E and NE in adrenals of placebo treated LP and SP birds, significant effect of melatonin treatment was observed only in SP birds. The results suggest that influences of exogenous melatonin on the levels of both blood glucose and adrenal catecholamines are largely modulated by short rather than long photoperiods.

Electrophoretic investigation on seven species of Indian frogs

Studies on the occurrence of protein polymorphism are of importance not only in determining interspecific relationships but also in revealing genetically controlled variants among the populations of the same species. This study deals with the analysis of the isozyme pattern of three dehydrogenases in seven species of Indian frogs. The results correlate with the respective habitats and it is suggested that protein polymorphism is adaptively important and is maintained by natural selection.

Recent insights into the varying activity of estrogens

Recent advances have added substantially to our understanding of the biology of estrogens. Estrogens are no longer considered to differ only in potency. Two estrogens can have similar effects in one tissue and very different effects in another. Additionally, an estrogen can have different effects in different tissues. It is now recognized that there are at least two estrogen receptors, ER-alpha and ER-beta, and that it is quite likely that estrogens also work through non-genomic mechanisms. The development of new methods of chromatographic separation has aided substantially in our ability to characterize the composition of Premarin, including the identification of estradiene, the fourth-most abundant estrogen in Premarin. Recent studies have contributed to our understanding of the unique profile of Delta(8,9) dehydroestrone sulfate, another of the Premarin estrogens. It was found that Delta(8,9) dehydroestrone sulfate is an active estrogen with a distinct pharmacological profile that results in significant clinical activity in vasomotor, neuroendocrine and bone preservation parameters. However, it displayed little or no efficacy, at the dose studied, on other peripheral parameters normally affected by classical estrogens. Increasing knowledge of the unique profiles of the Premarin components, as well as their complex interaction, will help to increase our understanding of the clinical profile of Premarin.

On the Nature of the Compact Star in 4U 1728-34

The discovery of kilohertz quasi-periodic oscillations (kHz QPOs) in low-mass X-ray binaries (LMXBs) with the Rossi X-Ray Timing Explorer has stimulated extensive studies of these sources. Recently, Osherovich & Titarchuk suggested a new model for kHz QPOs and the related correlations between kHz QPOs and low-frequency features in LMXBs. Here we use their results to study the mass-radius relation for the atoll source 4U 1728-34. We find that, if this model is correct, 4U 1728-34 is possibly a strange star rather than a neutron star.

Estrogen activity and novel tissue selectivity of delta8,9-dehydroestrone sulfate in postmenopausal women

Recent basic and clinical advances have consolidated the concept of tissue-selective estrogens, i.e. molecules that express different degrees of partial agonist, full agonist or antagonist activity in different tissues or cells. Delta8,9-Dehydroestrone sulfate (delta8,9-DHES) is a conjugated estrogen and a component of conjugated equine estrogens (CEE). It is metabolized in the human in at least a 1:1 ratio to its 17beta form, 17beta-delta8,9-DHES. To evaluate its activity in different clinical and biochemical parameters, a clinical research study was conducted with delta8,9-DHES and estrone sulfate as a comparator in postmenopausal women. Delta8,9-DHES was given orally at a daily dose of 0.125 mg for 12 weeks in a group of 10 women. Two additional groups of women received either estrone sulfate alone (1.25 mg/day) or the combination of delta8,9-DHES and estrone sulfate at the previously specified doses. A significant and consistent suppression of hot flushes (number, severity, and total score) was observed with delta8,9-DHES, reaching more than 95% suppression in all parameters of vasomotor symptoms. This level of activity was equal to that obtained with the much higher dose of estrone sulfate, and it was sustained for the duration of the treatment period (12 weeks). Measurements of a bone resorption marker, i.e. urinary excretion of N-telopeptide, demonstrated that delta8,9-DHES at 8 weeks produced a degree of suppression (40%) similar to that observed with the higher dose of estrone sulfate. Gonadotropin secretion (FSH and LH) was significantly suppressed in women receiving delta8,9-DHES, similar to that observed with estrone sulfate alone or with the combination of the two. Other parameters, such as total cholesterol, low density lipoprotein cholesterol and high density lipoprotein cholesterol were not modified significantly, whereas serum globulins (sex hormone-binding globulin and corticosteroid-binding globulin) showed only marginal increases after delta8,9-DHES administration. Taken together with preclinical data, it is found that delta8,9-DHES is an active estrogen with a distinct pharmacological profile that results in significant clinical activity in vasomotor, neuroendocrine (gonadotropin and PRL) and bone preservation parameters, whereas displaying little or no efficacy, at the dose tested, on other peripheral parameters normally affected by estrogens. Collectively, this information supports the concept that delta8,9-DHES is an integral component of CEE, with distinct tissue selectivity contributing to the CEE's overall clinical activity, and places this estrogen as a distinct member of a novel class of centrally active molecules with unique peripheral tissue selectivity.

Effects of equine oestrogens on markers of vasoactive function in human coronary artery endothelial cells

A large proportion of the beneficial effects that oestrogens demonstrate on the vasculature are believed to be mediated via direct effects on the vascular wall. In this study we compared a number of oestrogenic compounds isolated from pregnant mare's urine including 17beta-oestradiol and oestrone, in terms of their abilities to inhibit stimulated endothelin-1 release from normal human coronary artery endothelial cells (CAEC). We also examined their ability to stimulate expression of constitutive endothelial nitric oxide synthase (eNOS) and explored their effects on cellular angiotensin converting enzyme (ACE). All the oestrogens tested were able to inhibit serum-stimulated ET-1 release. Oestrone and 17alpha-dihydroequilenin failed to significantly affect cellular eNOS levels. 17Beta-oestradiol and oestrone significantly increased cellular ACE levels while 17beta,delta(8,9)-dehydroestradiol decreased cellular ACE. We discuss these observations in terms of their potential clinical relevance and use as a means of screening novel oestrogen-like compounds.

The neuropeptides, VIP and NPY, that are present in the thyroid nerves are not released into the thyroid vein

In the present study, we tested the hypothesis that the neuropeptides, vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), which are present in the thyroid nerves, act as physiological neurotransmitters involved in the regulation of thyroid hormone secretion and thyroid blood flow. Specifically, we examined whether these neuropeptides can be released into thyroid blood vessels by electrical stimulation of the major thyroid nerves or whether their expression is altered by changes in iodine intake. Sprague-Dawley rats were used in this study. The cervical sympathetic trunk or the superior laryngeal nerve was stimulated by bipolar electrodes in anesthetized rats. During nerve stimulation, blood samples were withdrawn from the thyroid vein. Thyroid blood flow was monitored by laser Doppler blood flowmetry. Sympathetic stimulation caused a marked decrease in thyroid blood flow, which was associated with a significant increase in release of norepinephrine. However, these effects were not accompanied by any change in NPY release into the thyroid vein. Stimulation of the superior laryngeal nerve was not associated with changes in thyroid blood flow or VIP release into the thyroid vein. In a separate experiment, rats were fed a diet containing low-, high-, or normal iodine concentrations. Triiodothyronine (T3) and thyroxine (T4) levels in thyroid venous plasma were significantly reduced in rats fed a low-iodine diet but not in a separate group of rats fed a high iodine diet. However, these treatments had no effect on VIP or NPY concentrations in thyroid venous plasma or in thyroid ganglia. Thus, our results indicate that VIP and NPY, which are present in the thyroid nerves, may not be directly involved in the regulation of thyroid function.

Immunostimulation of murine spleen cells by materials associated with bovine milk protein fractions

Purified bovine milk proteins that were added to cultures of murine spleen cells significantly increased cell proliferation and production of immunoglobulin M. Casein and a whey mixture consisting of alpha-lactalbumin, bovine serum albumin, bovine gamma globulin, and beta-lactoglobulin (beta-LG) were stimulatory. Of the three beta-LG preparations that are commercially available (beta-LG containing variants A and B, purified variant A, and purified variant B), the unseparated mixture containing both the A and B variants showed the most immunomodulatory activity. Both alkaline treatment and trypsin digestion of the beta-LG preparation markedly reduced its effectiveness. Polymyxin B, while greatly diminishing the stimulatory effect of lipopolysaccharide, had no significant effect on either the enhancement of cell proliferation or the enhancement of immunoglobulin production by beta-LG. In the presence of S-(n-butyl)-homocysteine sulfoxamine, the stimulatory effect of beta-LG on cell proliferation and IgM production in vitro was markedly reduced.

Diurnal sensitivity of the testes to exogenous testosterone propionate in sexually regressed whitethroated munia Lonchura malabarica

The testes in different groups of whitethroated munia (Lonchura malabarica) were studied following exogenous treatment of testosterone propionate (1 mg/100 g body wt./day) at 06.00 h or 14.00 h or 22.00 h for 15 consecutive days during the quiescent phase of the annual testicular cycle. The testicular conditions in each group of testosterone treated and appropriate control (administered only with the vehicle of hormone at corresponding time-points) group of birds were analyzed by the studies of paired testicular weight, seminiferous tubular diameter, spermatogenetic index, and cytology of the testicular germ cells. The results of the study revealed that exogenous testosterone was stimulatory to the testicular functions irrespective of the time of treatment. The gametokinetic response of the testes to exogenous testosterone also did not show any statistical difference among the birds treated at different hours of the day. The present study demonstrates for the first time that the responses of the testes to exogenous testosterone during the post-breeding phase in an annual testicular cycle of a wild bird does not vary with the time of administration.

Analysis of high-mass biomolecules using electrostatic fields and matrix-assisted laser desorption/ionization in a Fourier transform mass spectrometer

A new decelerating technique that places dc potentials on the orthogonal excitation and receiver plates as well as the rear trapping plate (conductance limit) of the source cell of a dual cubic cell has been applied to the standard matrix-assisted laser desorption/ionization Fourier transform mass spectrometry technique. When this five-plate trapping method is applied, high-mass ions with large translational kinetic energies can be trapped efficiently and detected. Using this approach, low-resolution spectra of carbonic anhydrase (MW = 29,000), egg albumin (MW = 45,000), and bovine albumin (MW = 66,000) have been obtained. Because the new decelerating method requires no modification to the existing cell, it is also possible to obtain high-resolution spectra for compounds with masses of ca. 14,000 Da and lower. Utilizing the five-plate trapping method, a bovine insulin spectrum with a resolving power of 20,000 was obtained. It is not yet possible to obtain higher resolution for the higher mass proteins. The reasons for this difficulty are currently being investigated.