Galectin-3 as a novel biomarker in cats with hypertrophic cardiomyopathy

INTRODUCTION/OBJECTIVES

Galectin-3 (Gal-3) is a circulating biomarker of fibrosis. In humans, increased Gal-3 is predictive of myocardial fibrosis and adverse cardiac events. The aim of this study was to evaluate the potential for Gal-3 as a cardiac biomarker in cats with hypertrophic cardiomyopathy (HCM).

MATERIALS AND METHODS

Eighty cats were enrolled (25 healthy cats with normal hearts, 35 with HCM American College of Veterinary Internal Medicine (ACVIM) stage B, and 21 with HCM ACVIM stage C). Each cat received a full echocardiogram, health panel, and total thyroxin level. Galectin-3 levels were measured for each enrolled patient. Troponin I and N-terminal pro-brain natriuretic peptide (NT-proBNP) were obtained for the majority of cats. Additionally, 17 ACVIM stage B cats underwent cardiac-gated magnetic resonance (CMR) imaging to assess myocardial extracellular volume (ECV), a noninvasive measure of myocardial fibrosis.

RESULTS

Galectin-3 levels are increased in cats with HCM ACVIM stage B and C compared to healthy cats; however, no significant differences were detected between ACVIM stage B and ACVIM stage C cats. In HCM-affected cats, Galectin-3 showed statistically significant correlations with left atrial dimensions, left atrial:aorta ratio, and CMR-derived ECV. Quantitative NT-proBNP showed excellent discrimination between all groups and troponin I was able to discriminate between ACVIM stage C and normal cats, but not between other groups.

CONCLUSIONS

Circulating Gal-3 levels are increased in cats with HCM and is positively correlated with left atrial dimensions and ECV in affected cats. Further studies evaluating the relationship between Gal-3, myocardial fibrosis, and clinical outcomes are warranted.

Rehabilitation post-COVID-19: cross-sectional observations using the Stanford Hall remote assessment tool

INTRODUCTION

The multisystem COVID-19 can cause prolonged symptoms requiring rehabilitation. This study describes the creation of a remote COVID-19 rehabilitation assessment tool to allow timely triage, assessment and management. It hypotheses those with post-COVID-19 syndrome, potentially without laboratory confirmation and irrespective of initial disease severity, will have significant rehabilitation needs.

METHODS

Cross-sectional study of consecutive patients referred by general practitioners (April-November 2020). Primary outcomes were presence/absence of anticipated sequelae. Binary logistic regression was used to test association between acute presentation and post-COVID-19 symptomatology.

RESULTS

155 patients (n=127 men, n=28 women, median age 39 years, median 13 weeks post-illness) were assessed using the tool. Acute symptoms were most commonly shortness of breath (SOB) (74.2%), fever (73.5%), fatigue (70.3%) and cough (64.5%); and post-acutely, SOB (76.7%), fatigue (70.3%), cough (57.4%) and anxiety/mood disturbance (39.4%). Individuals with a confirmed diagnosis of COVID-19 were 69% and 63% less likely to have anxiety/mood disturbance and pain, respectively, at 3 months.

CONCLUSIONS

Rehabilitation assessment should be offered to all patients suffering post-COVID-19 symptoms, not only those with laboratory confirmation and considered independently from acute illness severity. This tool offers a structure for a remote assessment. Post-COVID-19 programmes should include SOB, fatigue and mood disturbance management.

Enabling uptake and sustainability of supervision roles by women GPs in Australia: a narrative analysis of interviews

BACKGROUND

Worldwide, the proportion of women entering careers in medicine is increasing. To ensure diversity and capacity in the general practice ("GP") supervision workforce, a greater understanding from the perspective of women GPs engaged in or considering the clinical supervision of trainee doctors is important. This narrative inquiry aims to explore the uptake and sustainability of supervision roles for women GPs in the Australian context.

METHODS

Qualitative interviews with Australian women GPs were conducted between July and September 2021. Women GPs were selected to represent a range of demographics, practice contexts, and supervision experience to promote broad perspectives. Narrative analysis drew on participant perspectives, allowing emergent stories to be explored using story arcs based on the characters, settings, problems, actions, and resolutions. These stories were evaluated by a broad research team and a high level of agreement of the final narratives and counter-narratives was achieved.

RESULTS

Of the 25 women who enrolled, 17 completed interviews. Six narratives emerged, including: power and control, pay, time, other life commitments, quality of supervision, and supervisor identity. These represented significant intersecting issues with the potential to impact the uptake and sustainability of supervision by women GPs. Some women GPs reported a lack of agency to make decisions about their role in supervision and were not remunerated for teaching. Uptake and sustainability of supervision was constrained by other life commitments, which could be buffered by team-sharing arrangements and a supportive practice. Although adding a burden of time atop their complex and sensitive consultations, women GPs were committed to being available to registrars and supervising at a high standard. To foster high quality supervision, women GPs were interested in up-skilling resources, building experience and harnessing support networks. Women sensed imposter syndrome when negotiating a supervisor identity, which could be managed by explicitly valuing their contribution.

CONCLUSION

The findings can inform the development of more specific resources, supports and structures to enable women GPs in Australia to uptake and sustain the supervision of trainee doctors at a level they find both acceptable and rewarding.

Cannabidiol and refractory epilepsy: parental and caregiver perspectives of participation in a compassionate access scheme

Background

The Compassionate Access Scheme (CAS) being delivered through the Queensland Children’s Hospital is designed to allow access to an investigational purified Cannabidiol oral solution to paediatric patients with severe refractory epilepsy. The objectives of this study were to conduct semi-structured interviews to:

1. Understand families’ expectations and attitudes about the use of an investigational cannabinoid product for their child’s seizures;

2. Understand families’ perceptions of Cannabidiol’s efficacy for their child’s seizures; and other aspects of their child’s behaviour, quality of life and/or cognition.

Methods

Children aged 2-18 years had been enrolled in, or were enrolled in a compassionate access scheme for Cannabidiol at the time of the study. Semi-structured interviews (n = 19) with parents or caregivers (n = 23) of children diagnosed with refractory epilepsy were voice-recorded, transcribed and analysed to generate common themes.

Results

Key themes emerged relating to seizure activity, family and school engagement, drug safety and legal access, efficacy, clinical support, social acceptance of the medication and program delivery. The use of Cannabidiol was perceived to have benefits in relation to reducing the severity and frequency of seizure activity for almost a third of patients experiencing refractory epilepsy. Participants described other benefits including improved social engagement, wakefulness and a reduction of side effects related to a reduction of conventional medication dosage.

Conclusion

This study provided unique perspectives of families’ experiences managing untreatable epilepsy, their experiences with conventional and experimental pharmacological treatments and health services. Whilst families’ perceptions showed the use of Cannabidiol did not provide a therapeutic reduction in the seizure activity for all patients diagnosed with refractory epilepsy, it’s use as an additional pharmacological agent was perceived to provide other benefits by some patient families.

Paraneoplastic Limbic Encephalitis Secondary To Mixed Non-Seminomatous Germ Cell Tumours

Casestudy: Testicular tumors account for 1–2% of all tumors in men, with 95% of these being germ cell tumors. The main risk factor for the development of testicular cancer is cryptorchidism. Paraneoplastic limbic encephalitis is a rare sequela of testicular tumor associated with anti-Ma2 and KLH11 antibodies. The most effective treatment for paraneoplastic limbic encephalitis is treatment of the primary malignancy.

We present a 41-year-old male that presented to the emergency department with two weeks of episodic alteration of consciousness and memory disturbances. Negative neurologic evaluation and imaging led to concern for a paraneoplastic process from a distant malignancy. CT imaging revealed an enlarged, necrotic para-aortic lymph node and subsequent ultrasound demonstrated a right sided testicular mass. Right radical orchiectomy was performed.

Microscopically, the mass consisted of mixed respiratory epithelium, gastrointestinal glands and squamous epithelium with keratinization consistent with a post-pubertal testicular teratoma with associated in-situ germ cell neoplasia.

Resection of the para-aortic mass revealed large anaplastic cells with epithelioid features, nuclear pleomorphism and frequent mitoses. Immunostaining was positive for Pan-Keratin and OCT4, consistent with poorly differentiated embryonal carcinoma. Resection of the primary and metastatic disease, as well as treatment with corticosteroids resulted in resolution of the encephalitis.

This presentation of severe neurological disturbances in the setting of a metastatic mixed nonseminomatous germ cell tumor represents a rare presentation of paraneoplastic limbic encephalitis.

Physical activity and the prevention, reduction, and treatment of alcohol and other drug use across the lifespan (The PHASE review): A systematic review

The aim of this review is to systematically describe and quantify the effects of PA interventions on alcohol and other drug use outcomes, and to identify any apparent effect of PA dose and type, possible mechanisms of effect, and any other aspect of intervention delivery (e.g. key behaviour change processes), within a framework to inform the design and evaluation of future interventions. Systematic searches were designed to identify published and grey literature on the role of PA for reducing the risk of progression to alcohol and other drug use (PREVENTION), supporting individuals to reduce alcohol and other drug use for harm reduction (REDUCTION), and promote abstinence and relapse prevention during and after treatment of alcohol and other drug use (TREATMENT). Searches identified 49,518 records, with 49,342 excluded on title and abstract. We screened 176 full text articles from which we included 32 studies in 32 papers with quantitative results of relevance to this review. Meta-analysis of two studies showed a significant effect of PA on prevention of alcohol initiation (risk ratio [RR]: 0.72, 95%CI: 0.61 to 0.85). Meta-analysis of four studies showed no clear evidence for an effect of PA on alcohol consumption (Standardised Mean Difference [SMD]: 0.19, 95%, Confidence Interval -0.57 to 0.18). We were unable to quantitatively examine the effects of PA interventions on other drug use alone, or in combination with alcohol use, for prevention, reduction or treatment. Among the 19 treatment studies with an alcohol and other drug use outcome, there was a trend for promising short-term effect but with limited information about intervention fidelity and exercise dose, there was a moderate to high risk of bias. We identified no studies reporting the cost-effectiveness of interventions. More rigorous and well-designed research is needed. Our novel approach to the review provides a clearer guide to achieve this in future research questions addressed to inform policy and practice for different populations and settings.

Accounting for the impact of conservation on human well-being

Conservationists are increasingly engaging with the concept of human well-being to improve the design and evaluation of their interventions. Since the convening of the influential Sarkozy Commission in 2009, development researchers have been refining conceptualizations and frameworks to understand and measure human well-being and are starting to converge on a common understanding of how best to do this. In conservation, the term human well-being is in widespread use, but there is a need for guidance on operationalizing it to measure the impacts of conservation interventions on people. We present a framework for understanding human well-being, which could be particularly useful in conservation. The framework includes 3 conditions; meeting needs, pursuing goals, and experiencing a satisfactory quality of life. We outline some of the complexities involved in evaluating the well-being effects of conservation interventions, with the understanding that well-being varies between people and over time and with the priorities of the evaluator. Key challenges for research into the well-being impacts of conservation interventions include the need to build up a collection of case studies so as to draw out generalizable lessons; harness the potential of modern technology to support well-being research; and contextualize evaluations of conservation impacts on well-being spatially and temporally within the wider landscape of social change. Pathways through the smog of confusion around the term well-being exist, and existing frameworks such as the Well-being in Developing Countries approach can help conservationists negotiate the challenges of operationalizing the concept. Conservationists have the opportunity to benefit from the recent flurry of research in the development field so as to carry out more nuanced and locally relevant evaluations of the effects of their interventions on human well-being.

First results of the SOL reflectometer on Alcator C-Mod

A swept-frequency X-mode reflectometer has been built on Alcator C-Mod to measure the scrape-off layer (SOL) density profiles adjacent to the lower hybrid launcher. The reflectometer system operates between 100 and 146 GHz at sweep rates from 10 μs to 1 ms and covers a density range of ∼10(16)-10(20) m(-3) at B(0) = 5-5.4 T. This paper discusses the analysis of reflectometer density profiles and presents first experimental results of SOL density profile modifications due to the application of lower hybrid range-of-frequencies power to L-mode discharges. Comparison between density profiles measured by the X-mode reflectometer and scanning Langmuir probes is also shown.

Observation of self-generated flows in tokamak plasmas with lower-hybrid-driven current

In Alcator C-Mod discharges lower hybrid waves have been shown to induce a countercurrent change in toroidal rotation of up to 60 km/s in the central region of the plasma (r/a approximately <0.4). This modification of the toroidal rotation profile develops on a time scale comparable to the current redistribution time (approximately 100 ms) but longer than the energy and momentum confinement times (approximately 20 ms). A comparison of the co- and countercurrent injected waves indicates that current drive (as opposed to heating) is responsible for the rotation profile modifications. Furthermore, the changes in central rotation velocity induced by lower hybrid current drive (LHCD) are well correlated with changes in normalized internal inductance. The application of LHCD has been shown to generate sheared rotation profiles and a negative increment in the radial electric field profile consistent with a fast electron pinch.

10. Designing an online curriculum supporting risk management and patient safety

The Canadian Medical Protective Association (CMPA) is a not for profit mutual defence organization with a mandate to provide medico-legal assistance to physician members and to educate health professionals on managing risk and enhancing patient safety. To expand the outreach to its 72,000 member physicians, the CMPA built an online learning curriculum of risk management and patient safety materials in 2006. These activities are mapped to the real needs of members ensuring the activities are relevant. Eight major categories were developed containing both online courses and articles. Each course and article is mapped to the RCPSC's CanMEDS roles and the CFPC's Four Principles. This poster shares the CMPA’s experience in designing an online patient safety curriculum within the context of medico-legal risk management and provides an inventory of materials linked to the CanMEDS roles. Our formula for creation of an online curriculum included basing the educational content on real needs of member physicians; using case studies to teach concepts; and, monitoring and evaluating process and outcomes. The objectives are to explain the benefits of curricular approach for course planning across the continuum in medical education; outline the utility of the CanMEDS roles in organizing the risk management and patient safety medical education curriculum; describe the progress of CMPA's online learning system; and, outline the potential for moving the curriculum of online learning materials and resources into medical schools.

CARD15 polymorphisms in Behçet's disease

BACKGROUND

Behçet's disease (BD) is a chronic multi-system inflammatory disorder of unknown aetiology, which shares many features of the inflammatory bowel diseases (IBDs). CARD15 has recently been identified as the first susceptibility gene in Crohn's disease (CD).

OBJECTIVE

Given certain clinical and pathological similarities between CD and BD, and recent evidence of linkage of BD to the CARD15 genomic region, the aim of this study was to investigate the role of CARD15 variants in determining susceptibility to BD.

METHODS

We studied 374 BD patients from three ethnically homogeneous cohorts (white English, Turkish, and Middle Eastern Arabs of Palestinian and Jordanian descent). Mutation detection of CARD15 was performed by direct sequencing in a subset of patients from each group and the identified variants were genotyped in the complete cohorts. Case-control analyses were carried out with additional stratification by the BD-associated allele, HLA-B*51.

RESULTS

Mutation detection identified six previously described CARD15 polymorphisms at a frequency of > 3%. Additionally, two of the three CD-associated polymorphisms were present, but at low frequency. The frequency of haplotypes, constructed from nine genotyped polymorphisms, demonstrated significant variation between different ethnic groups. However, case-control analyses demonstrated no association between the CARD15 polymorphisms and susceptibility to BD, irrespective of HLA-B*51 status.

CONCLUSION

CARD15 variant alleles are not associated with susceptibility to BD. Other shared loci, currently under investigation, may determine susceptibility to both CD and BD.

Tolerability of topiramate in children and adolescents

OBJECTIVE

To examine the tolerability of topiramate (TPM) in paediatric practice.

METHODOLOGY

A retrospective cohort study of patients aged less than 18 years commenced on TPM by paediatric neurologists. Patients were identified from the dispensing databases of two paediatric tertiary referral hospitals and from the authority prescription records of four paediatric neurologists. The clinical data were obtained from the patients' medical records.

RESULTS

There were 159 patients who were identified as having been commenced on TPM and follow-up data were available for 127 (80%) patients. The median (range) age at commencement of TPM was 8.1 (0.5-17.9) years, with 12 patients aged less than 2 years. After 4 years, 60% of patients had ceased the medication. Treatment limiting adverse effects included aggression/psychosis (n = 10), cognitive impairment/sedation (n = 6), anorexia/weight loss (n = 4) and desquamation (n = 1). Prior aggression (hazard ratio 5.91 (2.12-16.44)) and female gender (hazard ratio 2.94 (1.02-8.41)) were risk factors for ceasing TPM because of an adverse event. Thirty percent of children commenced on TPM experienced a treatment limiting adverse effect within 2 years of commencement.

CONCLUSIONS

The frequency of treatment limiting adverse events in children receiving topiramate is higher than previously reported.

The application of thin layer activation for on-line erosion monitoring

The washout of volcanic ash into the feedwater of a hydroelectric power station resulted in enhanced erosion of generator components. The damage prompted two novel applications of the thin layer activation (TLA) technique. TLA was used to select more resistant materials, and also as the basis of an automated, on-line alarm system to warn station operators on the likelihood of further damage. The latter application demonstrated that plant protection against irregular events is practical using TLA.

Monosaccharide/proton symporter AtSTP1 plays a major role in uptake and response of Arabidopsis seeds and seedlings to sugars

The aim of this study was to investigate the in vivo properties and function of the high-affinity monosaccharide/proton symporter AtSTP1 of Arabidopsis. We isolated an Atstp1 knock-out mutant and found that this plant grows and develops normally. The AtSTP1 gene is expressed in germinating seeds and seedlings, with AtSTP1 activity found mainly in the seedling root. The rate of uptake of [(14)C]-3-O-methylglucose and [(14)C]-D-glucose is 60% less in Atstp1 seedlings than in the wild type, showing that AtSTP1 is the major monosaccharide transporter in Arabidopsis seedlings. Transport of D-galactose and D-mannose is also up to 60% less in Atstp1 seedlings compared to wild type, but transport of D-fructose, L-arabinose and sucrose is not reduced. Germination of Atstp1 seed shows reduced sensitivity to D-mannose, demonstrating that AtSTP1 is active before germination. Atstp1 seedlings grow effectively on concentrations of D-galactose that inhibit wild-type growth, even at up to 100 mM D-galactose, indicating that active transport by AtSTP1 plays a major role at very high concentrations of exogenous sugar. These findings provide insight into the physiological function of AtSTP1 and clearly establish its importance in the uptake of extracellular sugars by the embryo and in seedlings.

Properties of herbage in relation to equine dysautonomia: biochemical composition and antioxidant and prooxidant actions

To investigate the etiology of equine dysautonomia (ED), a degenerative polyneuropathy affecting grazing horses, the biochemical composition and antioxidant/prooxidant activities of aqueous extracts of plants collected from ED pastures were determined. Plants collected immediately after an outbreak of ED had reduced antioxidant and weak prooxidant activities when compared with control plants (plants collected from ED pastures out of ED season and control plants from ED pastures that were grown under favorable conditions). ED plants also had significantly increased concentrations of fructose and low molecular weight phenolic compounds, significantly more of one amino acid zone (probably valine), significantly less tartaric acid, and a nonsignificant decrease in ascorbic acid content when compared with control plants from ED pastures that were grown under favorable conditions. These findings suggest that ED plants may be under oxidative stress, possibly due to chilling, drought, or fungal colonization. However, experimental drought and chilling of plants did not reproduce the biochemical alterations identified in ED plants. It is possible that the altered biochemical content of ingested plants may contribute, directly or indirectly, to the development of ED in grazing horses.

GPs' recognition of, and response to, influences on patients' medicine taking: the implications for communication

BACKGROUND

Research evidence suggests that patients' beliefs about medicines influence medicine taking. Therefore, it is important that GPs are able to both identify and take account of such beliefs in the consultation.

OBJECTIVES

The purpose of this study was to explore GPs' awareness of asthma patients' beliefs about medicine, and of the ways in which friends and family, television programmes and the Campaign for Asthma may influence these beliefs. We also wanted to consider how GPs believe they would feel, and their likely behaviour, when a patient refers to these influences in the consultation.

METHOD

Four events, drawn from 17 semi-structured interviews previously conducted with patients recently prescribed oral steroids (prednisolone), were used to compose a narrative account of a hypothetical patient's behaviour. The narrative described a series of scenarios to which GPs were asked to respond. It was sent to all GPs in Derbyshire (n = 476).

RESULTS

The response rate was 69%. Half judged that the scenarios which presented the patients' beliefs about medicine, the influence of friends and family and the television were not 'realistic'. GPs also reported feeling more 'supportive' and 'sympathetic' towards the Campaign for Asthma as a source of patient information than they were towards opinions based on advice given by patients' family and friends.

CONCLUSION

Developing 'common ground' in the consultation will be problematic if GPs are not aware of, and sympathetic towards, the ways in which patients use information from a range of sources to formulate beliefs that then affect their medicine-taking behaviour. GPs should be encouraged to open up their discussions with patients so as to encourage the development of a partnership in which each party is aware of, and respects, the other's point of view.

Implicit and explicit memory in children with traumatic brain injury

This study aimed to investigate whether implicit memory is preserved in children with traumatic brain injury (TBI). A fragmented picture-completion procedure (Snodgrass, Smith, Feenan, & Corwin, 1987) was used to compare implicit and explicit memory of 12 children with severe long-term TBI and 12 controls, matched for age and gender. On the implicit memory task, both the TBI and control groups were found to show significant priming. In addition, the extent of priming for the two groups was not found to be different. On the explicit memory task, however, the TBI group was found to perform significantly more poorly than the control group. These results are consistent with those reported in the adult TBI literature and have implications for understanding and rehabilitating memory impairments in children with TBI.

[Evaluation of beta-cypermethrin for the control of Triatoma infestans]

This study assessed the insecticidal effect in the laboratory and in the field of the new pyrethroid beta-cypermethrin against Triatoma infestans, the vector of Chagaś disease, and compared it with that of deltamethrin. Comparison of the 50% lethal dosis (LD50) of both pyrethroids showed that beta-cypermethrin is more effective against the nymphs and that deltamethrin is more effective against the adults. Evaluation of the 50% lethal concentration (LC50) of the flowable formulations of both insecticides, placed on different surfaces, showed that their effectiveness on glass is similar, while on a ceramic surface deltamethrin is slightly more effective. The flowable formulations of the two insecticides were tested in 100 infested homes in the province of Santiago del Estero, Argentina. Deltamethrin was applied at a surface concentration of 25 mg/m2 and beta-cypermethrin at 50 mg/m2. The real surface concentrations of these products were analyzed from filter paper samples placed on walls and ceilings. Gas chromatography revealed good agreement with the target concentrations. In addition, entomological assessments were carried out 60, 90, 180, and 365 days after the treatments. Infestations were found only during the last assessment: in the peridomiciliary area of 10% of the houses treated with beta-cypermethrin and in 7% of the houses treated with deltamethrin (6% in the peridomiciliary area and 1% inside the house). The results indicate that beta-cypermethrin's effectiveness in controlling T. infestans when applied at a concentration of 50 mg/m2 is similar to that of deltamethrin applied at a concentration of 25 mg/m2.

Clinical features in 27 patients with Angelman syndrome resulting from DNA deletion

We report the clinical features in 27 Australasian patients with Angelman syndrome (AS), all with a DNA deletion involving chromosome 15(q11-13), spanning markers from D15S9 to D15S12, about 3 center dot 5 Mb of DNA. There were nine males and 18 females. All cases were sporadic. The mean age at last review (end of 1994) was 11 center dot 2 years (range 3 to 34 years). All patients were ataxic, severely retarded, and lacking recognisable speech. In all patients, head circumference (HC) at birth was normal but skewed in distribution, with 62 center dot 5% at the 10th centile. At last review HC was around the 50th centile in three patients (12 center dot 5%) while 15 had poor postnatal head growth. Short stature was not invariable, 5/26 (19%) were on or above the 50th centile. Hypotonia at birth was recorded in 15/24 (63%) and neonatal feeding difficulties were recorded in 20/26 (77%). Epilepsy was present in 26/27 (96%) with onset by the third year of life in 20 patients (83%). Improvement in epilepsy was reported in 11/16 patients (69%) with age. An abnormal EEG was reported in 25/25 patients. Hypopigmentation was present in 19/26 (73%). One patient had oculocutaneous albinism. Five patients could not walk independently. Of the remaining 22 who could walk, age of onset of walking ranged from 2 to 8 years. Disrupted sleep patterns were present in 18/21 patients (86%), with improvement in 9/12 patients (75%) over 10 years of age. The clinical features in this group of deletional AS patients were similar to previous reports, but these have not separated patients into subgroups based on DNA studies. In our group of deletional cases, 100% showed severe mental retardation, ataxic movements, absent language, abnormal EEG, happy disposition (noted in infancy in 95%), normal birth weight and head circumference at birth, and a large, wide mouth. These features occurred with a higher frequency than in AS patients as a whole. Our study also provided information on the evolution of the phenotype. The data can act as a benchmark for comparisons of AS resulting from other genetic mechanisms.

Cross-reactive antigens in the pathogenesis of onchocerciasis

The ocular disease associated with infection with Onchocerca volvulus is unique in that there is a wealth of epidemiological evidence to support the casual nature of the association but there is little known about the pathogenic mechanisms involved. We have identified a 44,000 M(r) component of ocular tissues that shows immunological cross-reactivity with an O. volvulus antigen. This immunological cross-reactivity between parasite and a component of host tissues may underlie the development of ocular disease in onchocerciasis. Preliminary experiments indicate that it is possible to initiate ocular disease in susceptible rats using the recombinant parasite antigen. This should allow the development of a laboratory model of ocular onchocerciasis and further our understanding of the mechanisms by which an infective organism can produce an auto-immune-like disease in the host.

Analysis of native collagen monomers and oligomers by size-exclusion high-performance liquid chromatography and its application

Collagen extracted from tissues by pepsin digestion is a mixture of monomeric and oligomeric molecules. The oligomers are held together by covalent crosslinks between molecules. A simple size-exclusion high-performance liquid chromatography (HPLC) method for separation of collagen monomers and oligomers using a Bio-Gel TSK 60XL column has been developed for type I collagen from calf skin. Factors influencing the resolution include flow rate, the protein concentration of the sample, and the injection volume. To overcome electrostatic interactions between the protein and the column packing, addition of sodium chloride to the mobile phase was required to recover protein from the HPLC column when using 5 mM acetic acid as the mobile phase. Optimum recovery and oligomer content were obtained at 0.25 M NaCl. Component peaks eluting from the column were identified as monomers and oligomers by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Application of the method showed that increasing the oligomer content of collagen preparations accelerated fibrillogenesis in vitro and decreased the ultimate fibril size produced. Also during fibrillogenesis, collagen oligomers were preferentially incorporated into fibrils, leaving only monomeric collagen in the soluble supernatant fraction. The assay was also shown to be useful for measurement of conversion of monomers to oligomers during accelerated aging of collagen fibrils at 30 degrees C in vitro.

Synthesis and bioactivity of new phosphorodithioates derived from N-substituted maleamic esters

1. A new series of organophosphorus compounds derived from N-substituted maleamic esters by reaction with dimethyl and diethyl phosphorodithioic acid was synthesized. 2. Two isomers, with chemical structures analogous to malathion were obtained for each maleamic ester assayed. 3. They were characterized, and their toxicity against a resistant strain of Musca domestica (strain G), a susceptible one (strain RAC) and Triatoma infestans (vector of Chagas' disease) were measured. 4. The structural chemical modification introduced by replacing a carboxyester group for a N-substituted amido one, reverted the resistance obtained for malathion. 5. Replacement of methyl by ethyl dithiophosphoric acid did not introduce significative differences. 6. In the case of Triatoma infestans, the synthesized compounds were less active than malathion.