Amplitude- and frequency-dependent activation of layer II/III neurons by intracortical microstimulation

Intracortical microstimulation (ICMS) has been used for the development of brain machine interfaces. However, further understanding about the spatiotemporal responses of neurons to different electrical stimulation parameters is necessary to inform the design of optimal therapies. In this study, we employed in vivo electrophysiological recording, two-photon calcium imaging, and electric field simulation to evaluate the acute effect of ICMS on layer II/III neurons. Our results show that stimulation frequency non-linearly modulates neuronal responses, whereas the magnitude of responses is linearly correlated to the electric field strength and stimulation amplitude before reaching a steady state. Temporal dynamics of neurons' responses depends more on stimulation frequency and their distance to the stimulation electrode. In addition, amplitude-dependent post-stimulation suppression was observed within ∼500 μm of the stimulation electrode, as evidenced by both calcium imaging and local field potentials. These findings provide insights for selecting stimulation parameters to achieve desirable spatiotemporal specificity of ICMS.

Restoration of benthic macrofauna promotes biogeochemical remediation of hostile sediments; An in situ transplantation experiment in a eutrophic estuarine-hypersaline lagoon system

Estuarine ecosystems have very high ecological and economic value, and also act as a buffer for coastal oceans by processing nutrient inputs from terrestrial sources. However, ongoing pressures from increased urbanisation and agriculture, overlaid by climate change, has reduced inflows and increased nutrient loads that challenge the health and buffering capacity of these ecosystems. This study aimed to investigate whether restoring the bioturbating activity of Simplisetia aequisetis (Polychaeta: Nereididae) and other macrofauna could improve biogeochemical conditions in 'hostile' (i.e. hypersaline, sulfide-rich) sediments. To achieve this aim, we conducted an in situ experiment in the Coorong estuarine-lagoon ecosystem, translocating hostile hypersaline sediments, devoid of bioturbating macrofauna, to a 'healthy' (lower salinity) location where macrobenthic fauna naturally occur, and manipulating the S. aequisetis density in the sediments. Porewater, solid-phase, and diffusive equilibrium and diffusive gradient in thin-films (DET/DGT) measurements showed that bioturbation by macrobenthic fauna significantly influenced sediment biogeochemistry and remediated hostile conditions in sediment within a short time (four weeks) irrespective of S. aequisetis density. Bioturbation promoted sediment oxygenation, while salinity and the concentrations of total organic carbon and porewater sulfide, ammonium, and phosphate all decreased over time at all sediment depths. This research highlights the importance of macrobenthic communities and their functional traits for improving sediment conditions, promoting resilience to eutrophication, providing a nature-based remediation option, and in general ensuring healthy functioning of estuarine ecosystems.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

THU0408 EFFECT OF NEW-ONSET GOUT ON KIDNEY TRANSPLANT OUTCOMES: A RETROSPECTIVE COHORT ANALYSIS OF THE UNITED STATES RENAL DATA SYSTEM

Background:

Gout is a frequent comorbidity in kidney transplant (KT) recipients. However, assessing the independent effect of gout on KT outcomes is difficult because of multiple confounders (e.g., temporal changes in estimated glomerular filtration rate [eGFR], cyclosporine or tacrolimus dose, urate-lowering medication use) that obscure a clear picture of gout’s potential impact.

Objectives:

This investigation assessed if the development of new-onset gout after KT was an independent risk factor for loss of graft function, as assessed by the need for maintenance hemodialysis following KT.

Methods:

This retrospective cohort study analyzed data on patients in the United States Renal Data System (USRDS) who received a primary KT between 1/1/2008 and 12/31/2015. The date of transplantation was the ‘index’ date. Eligible patients were required to have ≥24 months of Medicare coverage and no prior history of gout, defined as ≥1 claim with a gout diagnosis code in the 24 months prior to the index date. All patients were also required to have ≥12 months of coverage post index. Patients who died, experienced graft failure, or returned to dialysis <12 months post index were excluded. Because the first year following transplant is associated with the highest frequency of rejections, we evaluated subjects beginning 1 year after transplant. The exposure of interest was new-onset gout, defined as the presence of ≥2 claims for gout post index, and the primary endpoint was return to dialysis >12 months post index. Baseline time-invariant confounders included recipient and donor demographics and clinical characteristics at index. Time-varying confounders included body mass index (BMI) adjusted tacrolimus and cyclosporine dose, eGFR, and urate-lowering medication use post index. Patients who died or lost Medicare coverage >12 months post index were censored; all patients remaining at the end of the study period (12/31/2016) were also censored. A marginal structural model (MSM) was fitted to determine the relative risk of new-onset gout on return to dialysis, while controlling for both time-invariant and time-varying confounders.

Results:

18,525 of 466,589 KT recipients in the USRDS met study eligibility. Within the observation period, 1,399 (7.6%) developed new-onset gout and 1,420 (7.7%) returned to dialysis >12 months post index. Median time from index to new-onset gout and from index to return to dialysis was 16.2 months (IQR: 33.4) and 32.8 months (IQR: 28.4), respectively. Adjusting for baseline time-invariant and time-varying confounders via the MSM showed new-onset gout was associated with a 51% increased risk of return to dialysis >12 months post index (RR: 1.51, 95% CI: 1.03, 2.20).

Conclusion:

New-onset gout was independently associated with a 51% increased risk of return to dialysis >12 months after primary KT compared to a control cohort without gout. To our knowledge, this is the first observation of this outcome in an appropriately controlled cohort study of KT recipients with gout. Results from this analysis may have important implications for the monitoring and management of new-onset gout in the kidney transplant population.

References:

[1]Mandell BF.Cleve Clin J Med2008;75(Suppl 5):S5-8.

[2]Forbess LJ, Fields TR.Sem Arthritis Rheum2012;42:146-54.

[3]Gibson T.Curr Opin Rheumatol2012;24:127-31.

[4]Zhang L, et al.Nephrol Dial Transplant2012;27:1836-9.

[5]Clive DM.J Am Soc Nephrol2000;11:974-9.

[6]Kalantar E, et al.Transplant Proc2011;43:584-5.

[7]Lin HY, et al.N Engl J Med1989;321:287-92.

[8]Ben Hmida M, et al.Transplant Proc1995;27:2722-4.

[9]Kanbay M, et al.Transplant Proc2005;37:3119-20.

[10]Baroletti S, Bencivenga GA.Prog Transplant2004;14:143-7.

[11]Kim ED, et al.Am J Transplant2015;15:482-8.

[12]Kim DG, et al.PloS One2018;13:e0209156.

Disclosure of Interests: :

Justin Li: None declared, David Yin: None declared, Zheng Wang: None declared, Mark Brigham: None declared, Brian LaMoreaux Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Jeffrey Kent Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Megan Francis-Sedlak Shareholder of: Horizon Therapeutics, Employee of: Horizon Therapeutics, Richard Johnson Shareholder of: Colorado Research Partners LLC, XORTX Therapeutics, Consultant of: Horizon Therapeutics, Eli Lilly, Speakers bureau: Horizon Therapeutics, Nandini Hadker: None declared, Kevin Francis: None declared, Herman Sanchez: None declared, Gavin Miyasato: None declared

65 Improving Medicines Safety for Care Homes Residents

Introduction

Care home residents often have multiple, chronic conditions and are receiving complex treatment regimes, yet 30–50% of prescribed medicines are not taken as recommended [1]. Polypharmacy and medication errors are common. Evidence suggests that there is a linear increase in medication errors with the number of medications a patient is prescribed.

This paper describes an approach to identity and address inappropriate polypharmacy and safety concerns in Buckinghamshire care homes. The workforce used was: primary care and care home pharmacists, technicians and geriatricians.

Methods

A successful business proposal enabled a new interdisciplinary model of care to be established. This was delivered in 2768 Buckinghamshire care home beds (63% of Bucks ICS bed capacity). The CCG pharmacists, GPs and pharmacy technicians reviewed medication for all residents followed by a medication and clinical review by a geriatrician for the most complex individuals. Other community specialist teams were included as part of a Multidisciplinary team as needed. Data on reviews, medicines stopped and safety were collected from 2013–2018.

Results

Overall 2134 medications were stopped for 1268 residents of 2102 reviewed, with 505 interventions to reduce falls risk. 942 safety issues were identified and resolved. Total savings on medicines optimisation, waste and non-elective admission prevented was £619,000. System wide safety included: community psychiatric nurse to support dementia diagnosis, specialist enteral feeding nurse reinstated and a new website to share and disseminate good practice standards.

Conclusions

Future direction of this work focuses on system wide improvements to promote multi-organisational interdisciplinary healthcare and social services professionals work in care homes. NHSE Pharmacy integrated funding has provided extra pharmacists and technicians to support the 37% of the care home beds not yet covered by March 2020.

Reference

1. Horne R, Weinman J, Elliot R, et al. 2005, NHS National Coordinating Centre for service delivery and organisation report.

Treatment of 17α‑ethinylestradiol, 4‑nonylphenol, and carbamazepine in wastewater using an aerobic granular sludge sequencing batch reactor

This study quantifies the removal of a mixture of commonly detected emerging contaminants, 17α‑ethinylestradiol (EE2), 4‑nonylphenol (NP), and carbamazepine (CBZ) from synthetic wastewater using aerobic granular sludge in a sequential batch reactor. The emerging contaminant concentration in the influent wastewater was maintained near 500 μg/L for the duration of the experiment. Removal of EE2, NP, and CBZ is comprised of both adsorption and degradation. In general, the main removal mechanism for the emerging contaminants was initially adsorption, however it transitions to degradation as the adsorption capacity is saturated. The stabilized degradation for EE2 and NP in the SBR, was 16.09 μg/g and 20.05 μg/g, respectively. There was limited degradation of CBZ during the anaerobic phase. Both the Langmuir and Freundlich adsorption isotherms fit the data well and constants for the equations are calculated. The constants for the Langmuir Isotherm are found to be (X/m)_max = 36.23, b = 0.0019 for EE2 and (X/m)_max = 44.25, b = 0.0004 for CBZ. None of the tested compounds were found to be detrimental to the performance of the aerobic granules, and high macronutrient removal efficiency was maintained. The granule sludge bed and particle size were not negatively affected by EE2 and NP, however, carbamazepine appeared to interfere with the mechanism of granule formation resulting in a decrease in particle size during the experiment.

Low levels of genetic structuring in King George whiting Sillaginodes punctatus across two geographic regions

Postlarvae of King George whiting Sillaginodes punctatus, a commercially important fish species in southern Australia, were collected from multiple locations across south and south-eastern Australia. Genetic analyses using seven microsatellite markers found little evidence of genetic structure suggesting high levels of connectivity between the regions. The results found no evidence of a distinct source spawning population within the south-eastern range sampled in this study.

Consent to the use of aborted fetuses in stem cell research and therapies

This paper identifies the legal and policy framework relating to the use of aborted fetuses in stem cell research and therapies and contrasts this with the collection of embryos for research. It suggests that more attention should be given to questions about the kind of consent sought by researchers from women and that there should be more transparency about how aborted fetuses are used. It reports on variability in current practices of research ethics committees and researchers and uncertainty about the guidance available to them. It argues that there is a need for wide public discussion about the policy issues relating to fetal tissue use in stem cell research and the need for clarification of the law in this area.

Morning stiffness response with delayed-release prednisone after ineffective course of immediate-release prednisone

Objective: To assess morning stiffness in rheumatoid arthritis (RA) patients switched from immediate-release (IR) to delayed-release (DR) prednisone.

Method: Circadian Administration of Prednisone in Rheumatoid Arthritis-1 (CAPRA-1) is a 12-week, randomized, multicentre, active-controlled study of morning stiffness that consisted of a double-blind phase and a 9-month open-label extension. Patients receiving IR prednisone with no significant improvement after the double-blind study were switched to DR prednisone. Morning stiffness duration and median absolute and relative changes in pain and global assessment were evaluated (3, 6, and 9 months).

Results: In patients switched from IR to DR prednisone (n = 110), statistically significant reductions in morning stiffness occurred over 3 months and were sustained for 9 months. Absolute reduction of morning stiffness was ~50 min with > 40% relative reduction at each visit. Interleukin (IL)-6 levels were reduced by the same amount. Statistically significant and clinically meaningful mean reductions in morning stiffness were maintained at > 67 min at each visit along with significant improvements in pain and patient global assessment. There was no evidence of tachyphylaxis seen over the 9-month study.

Conclusions: Patients receiving disease-modifying anti-rheumatic drugs (DMARDs) and IR prednisone who had not had significant reductions in morning stiffness demonstrated statistically significant and clinically meaningful improvements when switched to DR prednisone.

Temporal and spatial patterns in ichthyoplankton assemblages in bay and open coastal environments

The larval fish fauna occurring in temperate bay and shelf waters off Victoria, southern Australia, was found to be diverse, comprising taxa from 52 families. The most abundant groups collected were gobiids, tripterygiids, gobiesocids and clupeids. Fish egg concentrations were highest during spring and summer (September to February). Eggs of the Australian anchovy Engraulis australis occurred mainly during spring (September to November). Total larval fish concentrations were highest during summer (December to February), and were significantly higher at 1 km than 2 and 5 km from shore in offshore samples. Larval concentrations of a number of families, mainly reef-associated taxa that attach their eggs to hard substrata, were also higher nearer to shore. These larvae are more developed upon hatching than those of pelagic spawners and more capable of avoiding passive drift. Multivariate analyses found that larval taxonomic composition did not vary significantly with distance from shore, but that seasonal and monthly groupings were evident, with different taxa dominating at different times of the year. Larvae of the families Gobiidae and Tripterygiidae occurred in all months, but were less abundant during winter. Spatial differences in the larval fish assemblage between offshore samples and samples taken in the bay were only apparent during summer. This was primarily due to a higher abundance of seagrass-associated species, such as syngnathids and hemiramphids, utilizing specific habitats in the bay.

OS046. Genome-wide association scans identify novel maternalsusceptibility loci for preeclampsia

INTRODUCTION

We have successfully utilized a family-based study design to localize several positional candidate preeclampsia susceptibility genes to chromosomes 2q22(ACVR2A,LCT,LRP1B,RND3,GCA),5q (ERAP2) and 13q(TNFSF13B). We now report on our continued positional cloning efforts using an alternative genome-wide association (GWA) mapping strategy in large Caucasian case-control cohorts from Australia and Norway.

OBJECTIVES

To identify maternal genetic risk loci for preeclampsia.

METHODS

The unrelated Australian samples (545 cases,547 controls) were genotyped using Illumina BeadChip technology (700K loci) and have been analyzed using PLINK. All unrelated Norwegian samples were genotyped across several Illumina BeadChip substrates and consist of 847 cases (700K loci) and 638 controls. The Norwegian control samples originate from other HUNT studies pertaining to migraine (n=95,700K loci), lung cancer (n=89,370K loci) and normal brain pathology (n=454,2.5M loci). To analyze a concordant set of 2.5-3 million genotypes across all Norwegian samples we are currently using MaCH to impute those loci not directly genotyped. The Norwegian GWA data will be analyzed in SOLAR utilizing empirical kinship estimates to account for any distant relatedness.

RESULTS

1078 Australian samples (538 cases,540 controls) and 648, 175 SNPs passed our quality control metrics. Two SNP associations (rs7579169,p=3.6×10(-7); rs12711941,p=4.3×10(-7)) satisfied our genome-wide significant threshold (p<5.1×10(-7)). These SNPs reside less than 15kb downstream from the 3 terminus of the Inhibin, beta B (INHBB) gene on 2q14.2. Sequencing of the INHBB locus in our patient cohort identified a third intergenic SNP to significantly associate with preeclampsia (rs7576192,p=1.5×10(-7)). These three SNPs confer risk (OR>1.56) and are in strong linkage disequilibrium with each other (r(2)>0.9) but not with any other genotyped SNP ±200kb. The analysis of the Norwegian GWAS is underway.

CONCLUSION

The Australian GWAS has identified a novel preeclampsia risk locus on chromosome 2q. The INHBB gene closest to our SNP associations is a plausible positional candidate susceptibility gene. There is a substantive body of evidence implicating inhibins, activins and other members of the TGF-βsuperfamily to have a role in the development of preeclampsia. The biological connection between ACVR2A and INHBB leads us to speculate that our linkage-based and GWA-based study designs, respectively, have identified a key biological pathway involved in susceptibility to preeclampsia.

The importance of continued surveillance of high risk cancer families as illustrated in a family with Gardner’s syndrome

1551

Background: The scientific community continues to rapidly discover cancer predisposition genes allowing high risk families to identify underlying genetic abnormalities providing more individualized medical management. Therefore, continued follow-up becomes critical and is exemplified by Family A, a case that had been lost to follow-up for almost 40 years. Family A was first reported in the literature in 1955 by Weiner and Cooper presenting with a dominant inheritance pattern of osteomatosis, multiple soft tissue tumors and colorectal adenomatosis polyposis consistent with several families previously reported by Gardner et al. between 1950–1953. The clinical diagnosis of Gardner syndrome was established. In 1969 Coli et al. further described the phenotypic manifestations of Family A’s second and third generations after which the family was largely lost to follow-up until two second generation members presented to our high-risk clinic. Methods: An updated family history was collected and compared to that previously reported in the literature. Results: An updated pedigree revealed new cases of breast, ovarian and primary peritioneal cancers in the second and third generations. A 39 year old woman diagnosed with a glioblastoma was also discovered. No family members had undergone genetic testing, however, analyses of the APC and BRCA genes are underway. Conclusions: The presence of multiple newly reported cases of breast and ovarian cancers within Family A raises concern for two independent cancer predisposition syndromes, Hereditary Breast and Ovarian Cancer Susceptibility syndrome (HBOCS) as well as Familial Adenomatous Polyposis (FAP). Though rarely gynecological tumors have been reported in FAP, this case emphasizes the need for practitioners to be aware of the potential presence of multiple hereditary cancer syndromes in one family. The dynamic changes in the pedigree of Family A underscore the importance of continued follow up for cancer families in which the underlying etiology is unknown. Such families should be followed in cancer genetics clinics to update family histories, ensure that appropriate screening regimens are followed, and to offer genetic testing if the appropriate analysis becomes available.

No significant financial relationships to disclose.

A framework linkage map of perennial ryegrass based on SSR markers

A moderate-density linkage map for Lolium perenne L. has been constructed based on 376 simple sequence repeat (SSR) markers. Approximately one third (124) of the SSR markers were developed from GeneThresher libraries that preferentially select genomic DNA clones from the gene-rich unmethylated portion of the genome. The remaining SSR marker loci were generated from either SSR-enriched genomic libraries (247) or ESTs (5). Forty-five percent of the GeneThresher SSRs were associated with an expressed gene. Unlike EST-derived SSR markers, GeneThresher SSRs were often associated with genes expressed at a low level, such as transcription factors. The map constructed here fulfills 2 definitions of a "framework map". Firstly, it is composed of codominant markers to ensure map transferability either within or among species. Secondly, it was constructed to achieve a level of statistical confidence in the support-for-order of marker loci. The map consists of 81 framework SSR markers spread over 7 linkage groups, the same as the haploid chromosome number. Most of the remaining 295 SSR markers have been placed into their most likely interval on the framework map. Nine RFLP markers and 1 SSR marker from another map constructed using the same pedigree were also incorporated to extend genome coverage at the terminal ends of 5 linkage groups. The final map provides a robust framework with which to conduct investigations into the genetic architecture of trait variation in this commercially important grass species.

The PTPN22 R620W polymorphism associates with RF positive rheumatoid arthritis in a dose-dependent manner but not with HLA-SE status

We have recently described the association between rheumatoid arthritis and a coding single-nucleotide polymorphism in the intracellular protein tyrosine phosphatase, PTPN22. The disease-associated polymorphism, 1858 C/T (rs2476601), encodes an amino-acid change (R620W) in one of four SH3 domain binding sites in the PTPN22 molecule. We have now extended our initial studies to address three questions: (1) Is the association with rheumatoid arthritis limited to rheumatoid factor (RF) positive disease? (2) Does homozygosity for PTPN22 R620W substantially increase disease susceptibility? (3) Is there an interaction between PTPN22 and the rheumatoid arthritis (RA)-associated HLA-DRB1 shared epitope alleles? A total of 1413 Caucasian rheumatoid arthritis patients and 1401 Caucasian controls were genotyped. The results support the view that PTPN22 was strongly and preferentially associated with RF positive disease (OR=1.75, 95% CI 1.46-2.10, P=1.3 x 10(-9)). The PTPN22 risk allele was not significantly associated with RF negative disease (OR=1.19, 95% CI 0.92-1.53, P=0.18), although a very weak association cannot be completely excluded. There was a strong dose effect on disease risk; two copies of the PTPN22 R620W allele more than doubles the risk for RF positive RA (OR=4.57, 95% CI 2.35-8.89). There was no evidence of a genetic association between PTPN22 and HLA susceptibility alleles.

Arteriolar Endothelial Dysfunction Is Restored in Ischaemic Muscles by Chronic Electrical Stimulation

Chronic intermittent electrical stimulation (15 min on, 85 min off, seven times per day) eliminated endothelial dysfunction of pre-capillary arterioles in ischaemic rat ankle flexor muscles. Responses to acetylcholine were restored from constriction to dilation, and the reduced dilation to bradykinin was corrected by 1 week of stimulation. Administration of the NOS inhibitor N(omega)-nitro-L-arginine for 1 week impaired arteriolar reactivity in a similar way to ischaemia, and dilator function was likewise restored by chronic stimulation. This suggests that nitric oxide production in the microcirculation is depressed by chronic ischaemia and that chronic electrical stimulation can specifically reverse this deficit. Stimulation applied to ischaemic muscles for 2 weeks also increased the numbers of microvessels immunostained for alpha-smooth muscle actin and the numbers of eNOS-positive microvessels and capillaries. These findings help to elucidate the mechanism of the beneficial effect of exercise in the treatment of peripheral vascular diseases by showing that muscle activity can improve both function and structural capacity of the microvasculature.

Remodeling in the microcirculation of rat skeletal muscle during chronic ischemia

OBJECTIVE

To establish the time course and extent of remodeling of terminal microcirculation in ischemic rat skeletal muscle during prolonged low flow that does not lead to inflammation.

METHODS

One common iliac artery was ligated via laparotomy in adult Sprague-Dawley rats and extensor digitorum longus (EDL) muscles removed at intervals (1, 2, and 5 weeks) postsurgery. Serial frozen EDL sections were stained to show capillaries (alkaline phosphatase), cell proliferation (antibody to proliferating cell nuclear antigen [PCNA]), terminal microvessels (antibodies to alpha-smooth muscle actin (alpha-SMA) or endothelial nitric oxide synthase [eNOS]), and macrophages (antibodies to infiltrating and resident macrophages). Total muscle eNOS protein was quantified by standard Western blotting techniques.

RESULTS

Capillary proliferation was very limited in ischemic EDLs, with a modest 12% increase in the capillary/fiber ratio after 5 weeks, preceded at 2 weeks by increased numbers of PCNA-positive nuclei at capillary sites. There was no muscle necrosis or evidence of inflammation, based on macrophage staining. The number of terminal microvessels that were positive for alpha-SMA and <10 microm in diameter was fewer in ischemic EDLs at all time points, whereas the number of larger positive vessels was unchanged. eNOS-positive vessels <10 microm in diameter were stained similarly throughout ischemic muscles as the controls, and showed a similar increase in vessel/fiber ratio as the capillaries. The total eNOS protein level was similar to that in controls in ischemic EDLs after 1 and 2 weeks, but was 28% lower after 5 weeks.

CONCLUSIONS

Prolonged, moderate flow reduction to skeletal muscles does not necessarily lead to inflammation or extensive capillary growth. Based on eNOS staining, the terminal microcirculation remains intact, but the loss of alpha-SMA immunoreactivity may indicate remodeling involving the "deinvestment" of microvessels by smooth muscle.

Reconstruction of the temporomandibular joint autogenous compared with alloplastic

The aims of and indications for temporomandibular joint (TMJ) reconstruction are well-established but the method of reconstruction is controversial. We describe a retrospective, two-centre audit of 49 patients treated with costochondral grafting and 50 patients treated with alloplastic joints. The characteristics of the patients were similar in both centres and the minimum follow-up period was 2 years. For each patient a number of variables were recorded including both subjective scores (pain and interference with eating) and objective data (interincisal distance). Patients in both groups showed an improvement in symptoms but more patients required reoperation in the autogenous group.

Innovation and regulation in human implant technologies: developing comparative approaches

Human implant technologies are subject to continual innovation and proliferation, raising important issues for technology testing, healthcare sciences, clinical performance and risk assessment, and regulation. The regulatory environment of medical devices is being shaped by harmonisation of standards in the European Union. The aim of this paper is to compare the histories and current regulatory environment of two technologies, breast implants and artificial hips, and to consider the implications of this comparison for a sociological healthcare research agenda to investigate the issues raised. The main focus is upon developments in the United Kingdom. Major points of contrast between the two technologies include the institutional contexts in which clinical evidence has been marshalled for government attention; the relative importance of strategic alliances between clinicians and manufacturers in the innovation process; the degree of public controversy evident; the varying definitions of an 'adverse incident' within medical device vigilance systems; and in the UK the presence of a national register for breast implants but not for hip implants. Inter-national contrasts in these dimensions are noted. The analysis suggests that improved understanding is required of the institutional, organisational and professional processes involved in implant technology innovation and regulation. A comparative research agenda is proposed, focusing upon: innovativeness and proliferation; safety and technological standards; clinical and social outcomes; and consumer/user information and choice. It is concluded that research in these areas will enhance the 'evidence-base' for the evaluation of human implant technologies in the context of their innovatory and regulatory environments.

Marek's disease virus latency

MDV latency is defined as the persistence of the viral genome in the absence of production of infectious virus except during reactivation. A number of systems for studying MDV latency exist, and most involve the use of lymphoblastoid cells or tumors. It has been difficult to divorce latency and transformation. Understanding the relationship between these two states remains a major challenge for the MDV system. Based on their patterns of expression, the MDV LATs are apt to be important in the balance between latent and lytic infections. The LATs are a complex group of transcripts. The profile of gene expression that characterizes latency differs among all herpesviruses, and MDV is no exception. MDV LATs bear little resemblance to LATs of other alphaherpesviruses or to the LATs of other lymphotropic herpesviruses. LAT splicing patterns are complex and the relationships among various spliced species or between these species and the large 10-kb transcript are unknown. In addition, the existence of any protein gene products of significance is unknown at this time. More work is needed to further investigate the significance and function of these RNAs. Better technology to construct mutants in the MDV system is badly needed, since the analysis of mutants in the chicken is a powerful and unique advantage of the MDV system.

Differential occupancy of somatodendritic and postsynaptic 5HT(1A) receptors by pindolol: a dose-occupancy study with [11C]WAY 100635 and positron emission tomography in humans

Augmentation of selective serotonin reuptake inhibitors (SSRIs) therapy by the 5-HT(1A) receptor agent pindolol may reduce the delay between initiation of antidepressant treatment and clinical response. This hypothesis is based on the ability of pindolol to block 5-HT(1A) autoreceptors in the dorsal raphe nuclei (DRN) and to potentiate the increase in 5-HT transmission induced by SSRIs. However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT(1A) receptors during treatment with pindolol controlled release (CR) in nine healthy volunteers with Positron Emission Tomography and [11C]WAY 100635. Subjects were studied four times: at baseline, following one week of pindolol CR 7.5 mg/day (4 and 10 hrs post dose), and following one dose of pindolol CR 30 mg(4 hrs post dose). Occupancy of the DRN was 40 +/- 29% on scan 2, 38 +/- 26% on scan 3, and 64 +/- 15% on scan 4. The average occupancy in all other regions was significantly lower at each doses (18 +/- 5% on scan 2, 12 +/- 3% on scan 3, and 42 +/- 4% on scan 4). These results suggest that the blockade in the DRN reached in clinical studies (7.5 mg/day) might be too low and variable to consistently augment the therapeutic effect of SSRIs. However, these data indicate that pindolol exhibits in vivo selectivity for the DRN 5-HT(1A) autoreceptors. As DRN selectivity is desirable for potentiation of 5-HT function, this observation represents an important proof of concept for the development of 5-HT(1A) agents in this application.

Physiological changes during carbon dioxide inhalation in patients with panic disorder, major depression, and premenstrual dysphoric disorder: evidence for a central fear mechanism

BACKGROUND

Inhalation of carbon dioxide (CO(2)) has been shown to produce more anxiety in patients with panic disorder (PD) than in healthy comparison subjects or patients with most other psychiatric illnesses tested, although premenstrual dysphoric disorder (PMDD) may be an exception. Several reasons have been proposed to explain CO(2) breathing effects in PD. We examined differences in respiratory response to CO(2) breathing in 4 groups to address these issues.

METHODS

Patients with PD (n = 52), healthy controls (n = 32), patients with PMDD (n = 10), and patients with major depression without panic (n = 21) were asked to breathe 5% and 7% CO(2). Continuous measures of respiratory physiological indices were made.

RESULTS

Carbon dioxide breathing produced the expected increases in all 4 respiratory variables measured. More patients with PD and PMDD had panic attacks than did controls or patients with major depression. Subjects who experienced panic during 5% or 7% CO(2) inhalation had the most extreme increases regardless of diagnostic group. Among patients with PD, baseline end-tidal carbon dioxide levels were significantly lower in those who subsequently had a panic attack during 5% CO(2) breathing than those who did not.

CONCLUSIONS

Although CO(2) breathing causes a higher rate of panic attacks in patients with PD than other groups (except PMDD), the physiological features of a panic attack appear similar across groups. Once a panic attack is triggered, minute ventilation and respiratory rate increase regardless of whether the subject carries a PD diagnosis. These findings are compatible with preclinical fear conditioning models of anxiogenesis.

Positron emission tomography study of pindolol occupancy of 5-HT(1A) receptors in humans: preliminary analyses

Preclinical studies in rodents suggest that augmentation of serotonin reuptake inhibitors (SSRIs) therapy by the 5-hydroxytryptamine(1A) (5-HT(1A)) receptor agent pindolol might reduce the delay between initiation of treatment and antidepressant response. This hypothesis is based on the ability of pindolol to potentiate the increase in serotonin (5-HT) transmission induced by SSRIs, an effect achieved by blockade of the 5-HT(1A) autoreceptors in the dorsal raphe nuclei (DRN). However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT(1A) receptors following treatment with controlled release pindolol in nine healthy volunteers with positron-emission tomography (PET). Each subject was studied four times: at baseline (scan 1), following 1 week of oral administration of pindolol CR (7.5 mg/day) at peak level, 4 h after the dose (scan 2), and at 10 h following the dose (scan 3), and following one dose of pindolol CR (30 mg) (at peak level, 4 h) (scan 4). Pindolol occupancy of 5-HT(1A) receptors was evaluated in the DRN and cortical regions as the decrease in binding potential (BP) of the radiolabelled selective 5-HT(1A) antagonist [carbonyl-(11)C]WAY-100635 or [carbonyl-(11)C] N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridyl)cyclohexa necarboxamide abbreviated as [(11)C]WAY-100635. Pindolol dose-dependently decreased [(11)C]WAY-100635 BP. Combining all the regions, occupancy was 20 +/- 8% at scan 2, 14 +/- 8% at scan 3, and 44 +/- 8% at scan 4. The results of this study suggest that at doses used in clinical studies of augmentation of the SSRI effect by pindolol (2.5 mg t.i.d.), the occupancy of 5-HT(1A) receptors is moderate and highly variable between subjects. This factor might explain the variable results obtained in clinical studies. On the other hand, at each dose tested, pindolol occupancy of 5-HT(1A) receptors was higher in the DRN compared to cortical regions, demonstrating a significant in vivo selectivity for DRN 5-HT(1A) autoreceptors relative to cortico-limbic postsynaptic receptors. This selectivity is necessary for the potentiation of 5-HT transmission, and this finding represents an important proof of concept in the development of 5-HT(1A) agents for this application. Early evaluation of new drugs with PET imaging will enable rapid screening of compounds based on DRN selectivity and more appropriate determination of doses for clinical trials.

Biodiversity hotspots for conservation priorities

Conservationists are far from able to assist all species under threat, if only for lack of funding. This places a premium on priorities: how can we support the most species at the least cost? One way is to identify 'biodiversity hotspots' where exceptional concentrations of endemic species are undergoing exceptional loss of habitat. As many as 44% of all species of vascular plants and 35% of all species in four vertebrate groups are confined to 25 hotspots comprising only 1.4% of the land surface of the Earth. This opens the way for a 'silver bullet' strategy on the part of conservation planners, focusing on these hotspots in proportion to their share of the world's species at risk.

Biodiversity hotspots for conservation priorities

Conservationists are far from able to assist all species under threat, if only for lack of funding. This places a premium on priorities: how can we support the most species at the least cost? One way is to identify 'biodiversity hotspots' where exceptional concentrations of endemic species are undergoing exceptional loss of habitat. As many as 44% of all species of vascular plants and 35% of all species in four vertebrate groups are confined to 25 hotspots comprising only 1.4% of the land surface of the Earth. This opens the way for a 'silver bullet' strategy on the part of conservation planners, focusing on these hotspots in proportion to their share of the world's species at risk.

Spectral sensitivity of vision and bioluminescence in the midwater shrimp Sergestes similis

In the oceanic midwater environment, many fish, squid, and shrimp use luminescent countershading to remain cryptic to silhouette-scanning predators. The mid-water penaeid shrimp, Sergestes similis Hansen, responds to downward-directed light with a dim bioluminescence that dynamically matches the spectral radiance of oceanic down-welling light at depth. Although the sensory basis of luminescent countershading behavior is visual, the relationship between visual and behavioral sensitivity is poorly understood. In this study, visual spectral sensitivity, based on microspectrophotometry and electrophysiological measurements of photoreceptor response, is directly compared to the behavioral spectral efficiency of luminescent countershading. Microspectrophotometric measurements on single photoreceptors revealed only a single visual pigment with peak absorbance at 495 nm in the blue-green region of the spectrum. The peak electrophysiological spectral sensitivity of dark-adapted eyes was centered at about 500 nm. The spectral efficiency of luminescent countershading showed a broad peak from 480 to 520 nm. Both electrophysiological and behavioral data closely matched the normalized spectral absorptance curve of a rhodopsin with lambda(max) = 495 nm, when rhabdom length and photopigment specific absorbance were considered. The close coupling between visual spectral sensitivity and the spectral efficiency of luminescent countershading attests to the importance of bioluminescence as a camouflage strategy in this species.

Influenza A among community-dwelling elderly persons in Leicestershire during winter 1993-4; cigarette smoking as a risk factor and the efficacy of influenza vaccination

In a prospective study of community-dwelling people 60-90 years of age, we examined the coverage of influenza vaccine during 1992-3 and 1993-4, the efficacy of vaccination in reducing serologically-confirmed clinical episodes of influenza A during 1993, and the effect of cigarette smoking. During 1992 and 1993, influenza vaccine was given to 106/215 (49%) and 120/204 (59%) people with risk conditions, and 84/225 (37%) and 103/235 (44%) without risk conditions. Influenza vaccination and general practitioner consultations during 1992 were independent predictors of vaccination in 1993, but current smoking was a negative predictor. Of 209 unimmunized people, 8/35 (23%) smokers had clinical influenza as compared with 11/174 (6%) non-smokers (OR 4.4, 95% CI 1.6 to 11.9). Of 371 non-smokers, 1/197 (0.5%) vaccinees had influenza as compared with 11/174 (6%) non-vaccinees (OR 0.075, 95% CI 0.587 to 0.009). No cases of influenza occurred among 21 current smokers who were vaccinated.

Comparison of two serotype 1 MDV isolates

We compared the RB1B and T. King (TK) serotype 1 isolates of Marek's disease virus (MDV) in vivo. Body and organ weights, mortality, and lesions indicated that the TK inoculum established early infection more efficiently than RB1B and did greater damage to the bursa of Fabricius and thymus. Subsequent studies showed that the TK inoculum that we used contained chicken infectious anemia virus (CIAV). Therefore, pathogenicity profiles shown here should be interpreted with the presence of CIAV contamination in the TK stock in mind.

Persistently negative HIV-1 antibody enzyme immunoassay screening results for patients with HIV-1 infection and AIDS: serologic, clinical, and virologic results. Seronegative AIDS Clinical Study Group

OBJECTIVE

To describe persons with HIV infection and AIDS but with persistently negative HIV antibody enzyme immunoassay (EIA) results.

DESIGN

Surveillance for persons meeting a case definition for HIV-1-seronegative AIDS.

SETTING

United States and Canada.

PATIENTS

A total of eight patients with seronegative AIDS identified from July 1995 through September 1997.

MAIN OUTCOME MEASURES

Clinical history of HIV disease, history of HIV test results, and CD4 cell counts from medical record review; results of testing with a panel of EIA for antibodies to HIV-1, and HIV-1 p24 antigen; and viral subtype.

RESULTS

Negative HIV EIA results occurred at CD4 cell counts of 0-230 x 10(6)/l, and at HIV RNA concentrations of 105,000-7,943,000 copies/ml. Using a panel of HIV EIA on sera from three patients, none of the HIV EIA detected infection with HIV-1, and signal-to-cut-off ratios were < or = 0.8 or all test kits evaluated. Sera from five patients showed weak reactivity in some HIV EIA, but were non-reactive in other HIV EIA. All patients were infected with HIV-1 subtype B.

CONCLUSIONS

Rarely, results of EIA tests for antibodies to HIV-1 may be persistently negative in some HIV-1 subtype B-infected persons with AIDS. Physicians treating patients with illnesses or CD4 cell counts suggestive of HIV infection, but for whom results of HIV EIA are negative, should consider p24 antigen, nucleic acid amplification, or viral culture testing to document the presence of HIV.

Effects of the common cold on mood and performance

Previous research has shown that both experimentally-induced and naturally occurring upper respiratory tract illnesses (URTIs) influence mood and mental functioning. None of the previous studies of naturally occurring colds has conducted appropriate virological assays to determine the nature of the infecting agent. This is an essential methodological step in studies of malaise associated with URTIs. The aim of this research was to investigate the effects of naturally occurring colds on mood and objective measures of performance. This was done by first conducting a cross-sectional comparison of 37 healthy people and 158 volunteers with colds and then a longitudinal study in which 100 volunteers developed colds and 87 remained healthy. Virological techniques were used to identify infecting agents and comparisons made across the different groups. The results showed that having a cold was associated with reduced alertness and slowed reaction times. These effects were observed both for colds where the infecting virus was identified and those where it was not. Similar effects were obtained for both rhinovirus and coronavirus colds. One may conclude that upper respiratory tract illnesses lead to a reduction in subjective alertness and impaired psychomotor functioning. This was true for both illnesses where the infecting agent was identified and for those clinical illnesses where no virus was detected. It is now important to identify the mechanisms linking infection and illness with the behavioural changes. Similarly, the impact of these effects on real-life activities such as driving needs examining. Finally, methods of treatment need to be developed which not only treat the local symptoms of the illnesses but remove the negative mood and the performance impairments.

Effect of antipanic treatment on response to carbon dioxide

BACKGROUND

Disordered breathing among patients with panic disorder, including hyperventilation during attacks and increased anxiogenic response to carbon dioxide (CO2) inhalation, is well established. We wished to assess whether there is a change in the physiological response to CO2 after patients have undergone antipanic therapy with either tricyclic antidepressants or cognitive behavioral therapy (CBT).

METHODS

Twenty-nine patients with panic disorder underwent baseline CO2 sensitivity testing using the traditional Read rebreathing method and then received either antidepressant treatment (n = 21) or CBT (n = 8). After completing treatment, CO2 testing was repeated. A comparison sample of 14 normal volunteers also had two CO2 sensitivity tests, separated by an average of 21.6 (SD = 8.8) weeks.

RESULTS

Using a liberal standard, in which all CO2 sensitivity tests whose correlations between minute ventilation and end-tidal CO2 were at least .75 were used, patients, but not controls, demonstrated a significant reduction in CO2 sensitivity between the first and second test. Using a more conservative .90 correlation standard reduced the sample size available and resulted in trend reduction in patients but no significant change in controls. There was a suggestion that the change was most pronounced in treatment responders, although the number of patient nonresponders is extremely small in this sample.

CONCLUSIONS

These data indicate that treatment reduces CO2 sensitivity in patients with panic disorder. We speculate that manipulation of the serotonergic and noradrenergic neurotransmission systems, both known to play a role in the control of respiration, may have a specific effect in reducing respiratory hyperactivity in panic disorder.

Acute viral infections of upper respiratory tract in elderly people living in the community: comparative, prospective, population based study of disease burden

OBJECTIVE

To evaluate the disease burden of upper respiratory infections in elderly people living at home.

DESIGN

Prospective surveillance of elderly people.

INTERVENTION

None.

SETTING

Leicestershire, England

SUBJECTS

533 subjects 60 to 90 years of age.

MAIN OUTCOME MEASURES

Pathogens, symptoms, restriction of activity, duration of illness, medical consultations, interval between onset of illness and medical consultation, antibiotic use, admission to hospital, and death.

RESULTS

231 pathogens were identified for 211 (43%) of 497 episodes for which diagnostic specimens were available: 121 (52%) were rhinoviruses, 59 (26%) were coronaviruses, 22 (9.5%) were influenza A or B, 17 (7%) were respiratory syncytial virus, 7 (3%) were parainfluenza viruses, and 3 (1%) were Chlamydia species; an adenovirus and Mycoplasma pneumoniae caused one infection each. Infections occurred at a rate of 1.2 episodes per person per annum (95% confidence interval 1.0 to 1.7; range 0-10) and were clinically indistinguishable. Lower respiratory tract symptoms complicated 65% of upper respiratory infections and increased the medical consultation rate 2.4-fold (chi 2 test P < 0.001). The median interval between onset of illness and medical consultation was 3 days for influenza and 5 days for other infections. Rhinoviruses caused the greatest disease burden overall followed by episodes of unknown aetiology, coronaviruses, influenza A and B, and respiratory syncytial virus.

CONCLUSIONS

Respiratory viruses cause substantial morbidity in elderly people. Although respiratory syncytial virus and influenza cause considerable individual morbidity, the burden of disease from rhinovirus infections and infections of unknown aetiology seems greater overall. The interval between onset of illness and consultation together with diagnostic difficulties raises concern regarding the role of antiviral drugs in treating influenza.