Does gabapentin provide benefit for patients with knee OA? A benefit-harm and cost-effectiveness analysis

OBJECTIVE

Gabapentin can treat neuropathic pain syndromes and has increasingly been prescribed to treat nociplastic pain. Some patients with knee osteoarthritis (OA) suffer from both nociceptive and nociplastic pain. We examined the cost-effectiveness of adding gabapentin to knee OA care.

METHOD

We used the Osteoarthritis Policy Model, a validated Monte Carlo simulation of knee OA, to examine the value of gabapentin in treating knee OA by comparing three strategies: 1) usual care, gabapentin sparing (UC-GS); 2) targeted gabapentin (TG), which provides gabapentin plus usual care for those who screen positive for nociplastic pain on the modified PainDETECT questionnaire (mPD-Q) and usual care only for those who screen negative; and 3) universal gabapentin plus usual care (UG). Outcomes included cumulative quality-adjusted life years (QALYs), lifetime direct medical costs, and incremental cost-effectiveness ratios (ICERs), discounted at 3% annually. We derived model inputs from published literature and national databases and varied key input parameters in sensitivity analyses.

RESULTS

UC-GS dominated both gabapentin-containing strategies, as it led to lower costs and more QALYs. TG resulted in a cost increase of $689 and a cumulative QALY reduction of 0.012 QALYs. UG resulted in a further $1,868 cost increase and 0.036 QALY decrease. The results were robust to plausible changes in input parameters. The lowest TG strategy ICER of $53,000/QALY was reported when mPD-Q specificity was increased to 100% and AE rate was reduced to 0%.

CONCLUSION

Incorporating gabapentin into care for patients with knee OA does not appear to offer good value.

Biodegradable ring-shaped implantable device for intravesical therapy of bladder disorders

Intravesical instillation is an efficient drug delivery route for the local treatment of various urological conditions. Nevertheless, intravesical instillation is associated with several challenges, including pain, urological infection, and frequent clinic visits for catheterization; these difficulties support the need for a simple and easy intravesical drug delivery platform. Here, we propose a novel biodegradable intravesical device capable of long-term, local drug delivery without a retrieval procedure. The intravesical device is composed of drug encapsulating biodegradable polycaprolactone (PCL) microcapsules and connected by a bioabsorbable Polydioxanone (PDS) suture with NdFeB magnets in the end. The device is easily inserted into the bladder and forms a 'ring' shape optimized for maximal mechanical stability as informed by finite element analysis. In this study, inserted devices were retained in a swine model for 4 weeks. Using this device, we evaluated the system's capacity for delivery of lidocaine and resiquimod and demonstrated prolonged drug release. Moreover, a cost-effectiveness analysis supports device implementation compared to the standard of care. Our data support that this device can be a versatile drug delivery platform for urologic medications.

Respirators in Healthcare: Material, Design, Regulatory, Environmental, and Economic Considerations for Clinical Efficacy

Maintaining an ample supply of personal protective equipment continues to be a challenge for the healthcare industry, especially during emergency situations and times of strain on the supply chain. Most critically, healthcare workers exposed to potential airborne hazards require sufficient respiratory protection. Respirators are the only type of personal protective equipment able to provide adequate respiratory protection. However, their ability to shield hazards depends on design, material, proper fit, and environmental conditions. As a result, not all respirators may be adequate for all scenarios. Additionally, factors including user comfort, ease of use, and cost contribute to respirator effectiveness. Therefore, a careful consideration of these parameters is essential for ensuring respiratory protection for those working in the healthcare industry. Here respirator design and material characteristics are reviewed, as well as properties of airborne hazards and potential filtration mechanisms, regulatory standards of governmental agencies, respirator efficacy in the clinical setting, attitude of healthcare personnel toward respiratory protection, and environmental and economic considerations of respirator manufacturing and distribution.

Dynamic omnidirectional adhesive microneedle system for oral macromolecular drug delivery

Oral drug administration remains the preferred route for patients and health care providers. Delivery of macromolecules through this route remains challenging because of limitations imposed by the transport across the gastrointestinal epithelium and the dynamic and degradative environment. Here, we present the development of a delivery system that combines physical (microneedle) and nonphysical (enhancer) modes of drug delivery enhancement for a macromolecule in a large animal model. Inspired by the thorny-headed intestinal worm, we report a dynamic omnidirectional mucoadhesive microneedle system capable of prolonged gastric mucosa fixation. Moreover, we incorporate sodium N-[8-(2-hydroxybenzoyl) amino] caprylate along with semaglutide and demonstrate enhanced absorption in swine resistant to physical displacement in the gastric cavity. Meanwhile, we developed a targeted capsule system capable of deploying intact microneedle-containing systems. These systems stand to enable the delivery of a range of drugs through the generation and maintenance of a privileged region in the gastrointestinal tract.

Implantable system for chronotherapy

Diurnal variation in enzymes, hormones, and other biological mediators has long been recognized in mammalian physiology. Developments in pharmacobiology over the past few decades have shown that timing drug delivery can enhance drug efficacy. Here, we report the development of a battery-free, refillable, subcutaneous, and trocar-compatible implantable system that facilitates chronotherapy by enabling tight control over the timing of drug administration in response to external mechanical actuation. The external wearable system is coupled to a mobile app to facilitate control over dosing time. Using this system, we show the efficacy of bromocriptine on glycemic control in a diabetic rat model. We also demonstrate that antihypertensives can be delivered through this device, which could have clinical applications given the recognized diurnal variation of hypertension-related complications. We anticipate that implants capable of chronotherapy will have a substantial impact on our capacity to enhance treatment effectiveness for a broad range of chronic conditions.

Patient and Health Care Worker Perceptions of Communication and Ability to Identify Emotion When Wearing Standard and Transparent Masks

IMPORTANCE

Adoption of mask wearing in response to the COVID-19 pandemic alters daily communication.

OBJECTIVE

To assess communication barriers associated with mask wearing in patient-clinician interactions and individuals who are deaf and hard of hearing.

DESIGN, SETTING, AND PARTICIPANTS

This pilot cross-sectional survey study included the general population, health care workers, and health care workers who are deaf or hard of hearing in the United States. Volunteers were sampled via an opt-in survey panel and nonrandomized convenience sampling. The general population survey was conducted between January 5 and January 8, 2021. The health care worker surveys were conducted between December 3, 2020, and January 3, 2021. Respondents viewed 2 short videos of a study author wearing both a standard and transparent N95 mask and answered questions regarding mask use, communication, preference, and fit. Surveys took 15 to 20 minutes to complete.

MAIN OUTCOMES AND MEASURES

Participants' perceptions were assessed surrounding the use of both mask types related to communication and the ability to express emotions.

RESULTS

The national survey consisted of 1000 participants (mean [SD] age, 48.7 [18.5] years; 496 [49.6%] women) with a response rate of 92.25%. The survey of general health care workers consisted of 123 participants (mean [SD] age, 49.5 [9.0] years; 84 [68.3%] women), with a response rate of 11.14%. The survey of health care workers who are deaf or hard of hearing consisted of 45 participants (mean [SD] age, 54.5 [9.0] years; 30 [66.7%] women) with a response rate of 23.95%. After viewing a video demonstrating a study author wearing a transparent N95 mask, 781 (78.1%) in the general population, 109 general health care workers (88.6%), and 38 health care workers who are deaf or hard of hearing (84.4%) were able to identify the emotion being expressed, in contrast with 201 (20.1%), 25 (20.5%), and 11 (24.4%) for the standard opaque N95 mask. In the general population, 450 (45.0%) felt positively about interacting with a health care worker wearing a transparent mask; 76 general health care workers (61.8%) and 37 health care workers who are deaf or hard of hearing (82.2%) felt positively about wearing a transparent mask to communicate with patients.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that transparent masks could help improve communication during the COVID-19 pandemic, particularly for individuals who are deaf and hard of hearing.

Kirigami-inspired stents for sustained local delivery of therapeutics

Implantable drug depots have the capacity to locally meet therapeutic requirements by maximizing local drug efficacy and minimizing potential systemic side effects. Tubular organs including the gastrointestinal tract, respiratory tract and vasculature all manifest with endoluminal disease. The anatomic distribution of localized drug delivery for these organs using existing therapeutic modalities is limited. Application of local depots in a circumferential and extended longitudinal fashion could transform our capacity to offer effective treatment across a range of conditions. Here we report the development and application of a kirigami-based stent platform to achieve this. The stents comprise a stretchable snake-skin-inspired kirigami shell integrated with a fluidically driven linear soft actuator. They have the capacity to deposit drug depots circumferentially and longitudinally in the tubular mucosa of the gastrointestinal tract across millimetre to multi-centimetre length scales, as well as in the vasculature and large airways. We characterize the mechanics of kirigami stents for injection, and their capacity to engage tissue in a controlled manner and deposit degradable microparticles loaded with therapeutics by evaluating these systems ex vivo and in vivo in swine. We anticipate such systems could be applied for a range of endoluminal diseases by simplifying dosing regimens while maximizing drug on-target effects through the sustained release of therapeutics and minimizing systemic side effects.

Personalized Radiation Attenuating Materials for Gastrointestinal Mucosal Protection

Cancer patients undergoing therapeutic radiation routinely develop injury of the adjacent gastrointestinal (GI) tract mucosa due to treatment. To reduce radiation dose to critical GI structures including the rectum and oral mucosa, 3D-printed GI radioprotective devices composed of high-Z materials are generated from patient CT scans. In a radiation proctitis rat model, a significant reduction in crypt injury is demonstrated with the device compared to without (p < 0.0087). Optimal device placement for radiation attenuation is further confirmed in a swine model. Dosimetric modeling in oral cavity cancer patients demonstrates a 30% radiation dose reduction to the normal buccal mucosa and a 15.2% dose reduction in the rectum for prostate cancer patients with the radioprotectant material in place compared to without. Finally, it is found that the rectal radioprotectant device is more cost-effective compared to a hydrogel rectal spacer. Taken together, these data suggest that personalized radioprotectant devices may be used to reduce GI tissue injury in cancer patients undergoing therapeutic radiation.

Association of knee OA structural phenotypes to risk for progression: a secondary analysis from the Foundation for National Institutes of Health Osteoarthritis Biomarkers study (FNIH)

PURPOSE

Aim was to stratify the knee MRIs of the Foundation for National Institutes of Health Osteoarthritis Biomarkers Consortium (FNIH) cohort into distinct structural phenotypes based on semiquantitative assessment and to determine risk for pain and structural progression over 48 months.

METHODS

The study sample from the FNIH project was selected as a nested case-control study with knees showing either 1) radiographic and pain progression (i.e., "composite" cases), 2) radiographic progression only ("JSL"), 3) pain progression only, and 4) neither radiographic nor pain progression. MRI was performed on 3T systems. MRIs were read according to the MOAKS scoring system. Knees were stratified into subchondral bone, cartilage/meniscus and inflammatory phenotypes using the baseline visits. The relation of each phenotype to risk of being in the combined JSL plus composite outcome or composite case only group compared to those not having that phenotype was determined using logistic regression. Only KL2 and 3 and those without root tears were included.

RESULTS

485 knees were included. 362 (75%) did not have any phenotype, while 95 (20%) had the bone phenotype, 22 (5%) the cartilage/meniscus phenotype and 19 (4%) the inflammatory phenotype. The bone phenotype was associated with a higher odds of the combined JSL plus composite outcome and composite outcome only (OR 1.81; [95%CI 1.14,2.85] and 1.65; 95%CI [1.04,2.61]) while the inflammatory (OR 0.96 [95%CI 0.38,2.42] and 1.25; 95%CI [0.48,3.25]) and the cartilage/meniscus phenotypes were not significantly associated with outcome (OR 1.30 95%CI [0.55,3.07] and 0.99; 95%CI [0.40,2,49]).

CONCLUSIONS

The bone phenotype was associated with increased risk of having both radiographic and pain progression. Phenotypic stratification may be useful to consider when selecting patients for inclusion in clinical trials.

Association of baseline and change in tibial and femoral cartilage thickness and development of widespread full-thickness cartilage loss in knee osteoarthritis - data from the Osteoarthritis Initiative

OBJECTIVE

To investigate whether baseline cartilage thickness and its longitudinal change are associated with incident widespread full-thickness cartilage loss (wsFTCL) in knee osteoarthritis, and whether there are optimal cut-off values for predicting wsFTCL.

METHODS

Central medial tibial (cMT) and femoral (cMF) cartilage were assessed using quantitative magnetic resonance imaging data from the Osteoarthritis Initiative cohort (N = 600 knees). Cartilage thickness was measured at baseline and 12 months. wsFTCL was defined semi-quantitatively (scores 2 and 3 from the MRI Osteoarthritis Knee Score) and its incidence at 24 months recorded. Logistic regression was used to determine the odds of developing wsFTCL for baseline and for each 0.1 mm decrease in cartilage thickness. Cut-off values were investigated using the minimal-p method and area under the Receiver Operating Characteristic curves (AUC).

RESULTS

Incident wsFTCL was observed in 66 (12%) and 73 (14%) knees in cMT and cMF, respectively. Lower baseline cMT and cMF cartilage thickness values were associated with wsFTCL (OR = 1.20; 95% CI: 1.11, 1.28 and OR = 1.15; 95% CI: 1.06 to 1.24, respectively). Optimal cut-off AUCs for the tibia and femur were 0.64 (0.57-0.70) and 0.63 (0.57-0.69), respectively. Longitudinal decrease in femoral, but not tibial, cartilage thickness was associated with incident wsFTCL (OR = 1.77; 95% CI: 1.30 to 2.40); optimal cut-off AUC 0.65 (95% CI: 0.58-0.72).

CONCLUSION

Lower baseline cMT and baseline/change (decrease) over 12 months in cMF cartilage thickness were associated with incident, location-specific, wsFTCL at 24 months. Optimal cut-off values were relatively low and of uncertain utility for predicting incident wsFTCL.

Temperature-responsive biometamaterials for gastrointestinal applications

We hypothesized that ingested warm fluids could act as triggers for biomedical devices. We investigated heat dissipation throughout the upper gastrointestinal (GI) tract by administering warm (55°C) water to pigs and identified two zones in which thermal actuation could be applied: esophageal (actuation through warm water ingestion) and extra-esophageal (protected from ingestion of warm liquids and actuatable by endoscopically administered warm fluids). Inspired by a blooming flower, we developed a capsule-sized esophageal system that deploys using elastomeric elements and then recovers its original shape in response to thermal triggering of shape-memory nitinol springs by ingestion of warm water. Degradable millineedles incorporated into the system could deliver model molecules to the esophagus. For the extra-esophageal compartment, we developed a highly flexible macrostructure (mechanical metamaterial) that deforms into a cylindrical shape to safely pass through the esophagus and deploys into a fenestrated spherical shape in the stomach, capable of residing safely in the gastric cavity for weeks. The macrostructure uses thermoresponsive elements that dissociate when triggered with the endoscopic application of warm (55°C) water, allowing safe passage of the components through the GI tract. Our gastric-resident platform acts as a gram-level long-lasting drug delivery dosage form, releasing small-molecule drugs for 2 weeks. We anticipate that temperature-triggered systems could usher the development of the next generation of stents, drug delivery, and sensing systems housed in the GI tract.

Endoscopically Injectable Shear-Thinning Hydrogels Facilitating Polyp Removal

Submucosal elevation, the process of instilling material in the submucosal space for separation of the surface mucosa and deeper muscularis layer, is a significant aspect of the endoscopic mucosal resection of large lesions performed to facilitate lesion removal and maximize safety. Submucosal injection, when applied, has historically been performed with normal saline, though this is limited by its rapid dissipation; solutions ideally need to be easily injectable, biocompatible, and provide a long-lasting submucosal cushion with a desirable height. Here, reported is a new set of materials, endoscopically injectable shear-thinning hydrogels, meeting these requirements because of their biocompatible components and ability to form a solid hydrogel upon injection. These findings are supported by evaluation in a large animal model and ultimately demonstrate the potential of these shear-thinning hydrogels to serve as efficient submucosal injection fluids for cushion development. Given these unique characteristics, their broad application in mucosal resection techniques is anticipated.

3D-Printed Gastric Resident Electronics

Long-term implantation of biomedical electronics into the human body enables advanced diagnostic and therapeutic functionalities. However, most long-term resident electronics devices require invasive procedures for implantation as well as a specialized receiver for communication. Here, a gastric resident electronic (GRE) system that leverages the anatomical space offered by the gastric environment to enable residence of an orally delivered platform of such devices within the human body is presented. The GRE is capable of directly interfacing with portable consumer personal electronics through Bluetooth, a widely adopted wireless protocol. In contrast to the passive day-long gastric residence achieved with prior ingestible electronics, advancement in multimaterial prototyping enables the GRE to reside in the hostile gastric environment for a maximum of 36 d and maintain ≈15 d of wireless electronics communications as evidenced by the studies in a porcine model. Indeed, the synergistic integration of reconfigurable gastric-residence structure, drug release modules, and wireless electronics could ultimately enable the next-generation remote diagnostic and automated therapeutic strategies.

Cost-effectiveness of health coaching and financial incentives to promote physical activity after total knee replacement

OBJECTIVE

We evaluated the cost-effectiveness of Telephonic Health Coaching and Financial Incentives (THC + FI) to promote physical activity in total knee replacement recipients.

DESIGN

We used the Osteoarthritis Policy Model, a computer simulation of knee osteoarthritis, to evaluate the cost-effectiveness of THC + FI compared to usual care. We derived transition probabilities, utilities, and costs from trial data. We conducted lifetime analyses from the healthcare perspective and discounted all cost-effectiveness outcomes by 3% annually. The primary outcome was the Incremental Cost-Effectiveness Ratio (ICER), defined as the ratio of the differences in costs and Quality-Adjusted Life Years (QALYs) between strategies. We considered ICERs <$100,000/QALY to be cost-effective. We conducted one-way sensitivity analyses that varied parameters across their 95% confidence intervals (CI) and limited the efficacy of THC + FI to 1 year or to 9 months. We also conducted a probabilistic sensitivity analysis (PSA), simultaneously varying cost, utilities, and transition probabilities.

RESULTS

THC + FI had an ICER of $57,200/QALY in the base case and an ICER below $100,000/QALY in most deterministic sensitivity analyses. THC + FI cost-effectiveness depended on assumptions about long-term efficacy; when efficacy was limited to 1 year or to 9 months, the ICER was $93,300/QALY or $121,800/QALY, respectively. In the PSA, THC + FI had an ICER below $100,000/QALY in 70% of iterations.

CONCLUSIONS

Based on currently available information, THC + FI might be a cost-effective alternative to usual care. However, the uncertainty surrounding this choice is considerable, and further research to reduce this uncertainty may be economically justified.

Is synovitis detected on non-contrast-enhanced magnetic resonance imaging associated with serum biomarkers and clinical signs of effusion? Data from the Osteoarthritis Initiative

OBJECTIVES

To determine the relationship between synovitis detected on non-contrast-enhanced (non-CE) magnetic resonance imaging (MRI), biochemical markers of inflammation, and clinical assessment of effusion in people with knee osteoarthritis (OA).

METHOD

We examined data from the OA Biomarkers Consortium within the Osteoarthritis Initiative (n = 600). Non-CE MRIs were semi-quantitatively scored (grades 0-3) for severity of Hoffa synovitis and effusion synovitis. Serum (s) matrix metalloproteinase-3 (sMMP-3), hyaluronic acid (sHA), and nitrated epitope of the α-helical region of type II collagen (sColl2-1NO2) were quantified. The bulge and patellar tap clinical tests were performed at baseline and performance characteristics were assessed for the detection of effusion synovitis on MRI. Multinomial logistic regression adjusted for covariates was used to assess the association between biochemical and imaging markers at baseline and over 12 and 24 months.

RESULTS

At baseline, sHA and sMMP-3 were associated with moderate to large (score ≥ 2, n = 117) effusion synovitis, with odds ratio = 1.35 and 1.30 per 1 standard deviation in biochemical markers (95% confidence intervals 1.07, 1.71 and 1.00, 1.69), c-statistics 0.640 and 0.626, respectively. The c-statistics for the presence of Hoffa synovitis (score ≥ 2) were 0.693, 0.694, and 0.694 for sHA, sMMP-3, and sColl2-1NO2, respectively. There was no significant association between biochemical markers (baseline and 12 and 24 month time-integrated concentrations) and changes in MRI markers. The bulge and patellar tap signs were 22.0% and 4.3% sensitive and 88.8% and 94.8% specific, respectively, for detecting effusion synovitis (score ≥ 1) on MRI.

CONCLUSIONS

sHA and sMMP-3 were modestly associated with effusion synovitis at baseline. Clinical signs of effusion are insensitive but highly specific for the presence of any effusion synovitis on non-CE MRI.

Elevated triglycerides are associated with decreased executive function among adolescents with bipolar disorder

OBJECTIVE

Cardiovascular risk factors that comprise metabolic syndrome (MetS) have been linked with cognition in adults with bipolar disorder (BD). This study examines the association between MetS components and executive function in adolescents with BD.

METHODS

A total of 34 adolescents with BD and 35 healthy control (HC) adolescents were enrolled. MetS components included triglycerides, high-density lipoprotein, glucose, waist circumference, and systolic and diastolic blood pressure. Executive functioning was measured using the intra-extra-dimensional (IED) set-shifting task from the Cambridge Neuropsychological Tests Automated Battery.

RESULTS

Adolescents with BD were more likely to have ≥1 MetS components (64.7%) as compared to HC participants (22.9%, χ(2) = 12.29, P = <0.001). Adolescents with BD also had poorer IED task performance compared to HC adolescents (composite Z-score: 0.21 ± 0.52 vs. 0.49 ± 0.51, P = 0.011). Within the BD group, IED composite Z-scores were correlated with diastolic blood pressure and triglyceride levels (ρ = -0.358, P = 0.041 and ρ = -0.396, P = 0.020 respectively). The association of triglycerides with executive function remained significant after controlling for age, IQ, and current use of second-generation antipsychotics.

CONCLUSION

Elevated triglycerides are associated with poorer executive function among adolescents with BD. Studies of behavioural and pharmacological interventions targeting MetS components for the purpose of improving executive function among adolescents with BD are warranted.

Model-based evaluation of cost-effectiveness of nerve growth factor inhibitors in knee osteoarthritis: impact of drug cost, toxicity, and means of administration

OBJECTIVE

Studies suggest nerve growth factor inhibitors (NGFi) relieve pain but may accelerate disease progression in some patients with osteoarthritis (OA). We sought cost and toxicity thresholds that would make NGFi a cost-effective treatment for moderate-to-severe knee OA.

DESIGN

We used the Osteoarthritis Policy (OAPol) model to estimate the cost-effectiveness of NGFi compared to standard of care (SOC) in OA, using Tanezumab as an example. Efficacy and rates of accelerated OA progression were based on published studies. We varied the price/dose from $200 to $1000. We considered self-administered subcutaneous (SC) injections (no administration cost) vs provider-administered intravenous (IV) infusion ($69-$433/dose). Strategies were defined as cost-effective if their incremental cost-effectiveness ratio (ICER) was less than $100,000/quality-adjusted life year (QALY). In sensitivity analyses we varied efficacy, toxicity, and costs.

RESULTS

SOC in patients with high levels of pain led to an average discounted quality-adjusted life expectancy of 11.15 QALYs, a lifetime risk of total knee replacement surgery (TKR) of 74%, and cumulative discounted direct medical costs of $148,700. Adding Tanezumab increased QALYs to 11.42, reduced primary TKR utilization to 63%, and increased costs to between $155,400 and $199,500. In the base-case analysis, Tanezumab at $600/dose was cost-effective when delivered outside of a hospital. At $1000/dose, Tanezumab was not cost-effective in all but the most optimistic scenario. Only at rates of accelerated OA progression of 10% or more (10-fold higher than reported values) did Tanezumab decrease QALYs and fail to represent a viable option.

CONCLUSIONS

At $100,000/QALY, Tanezumab would be cost effective if priced ≤$400/dose in all settings except IV hospital delivery.

Brief Report: Cartilage Thickness Change as an Imaging Biomarker of Knee Osteoarthritis Progression: Data From the Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium

OBJECTIVE

To investigate the association of cartilage thickness change over 24 months, as determined by magnetic resonance imaging (MRI), with knee osteoarthritis (OA) progression at 24-48 months.

METHODS

This nested case-control study included 600 knees with a baseline Kellgren/Lawrence (K/L) grade of 1-3 from 600 Osteoarthritis Initiative (OAI) participants. Case knees (n = 194) had both medial tibiofemoral radiographic joint space loss (≥0.7 mm) and a persistent increase in the Western Ontario and McMaster Universities Osteoarthritis Index pain score (≥9 on a 0-100 scale) 24-48 months from baseline. Control knees (n = 406) included 200 with neither radiographic nor pain progression, 103 with radiographic progression only, and 103 with pain progression only. Medial and lateral femorotibial cartilage was segmented from sagittal 3T MRIs at baseline, 12 months, and 24 months. Logistic regression was used to assess the association of change in cartilage thickness, with a focus on the central medial femorotibial compartment, and OA progression.

RESULTS

Central medial femorotibial compartment thickness loss was significantly associated with case status, with an odds ratio (OR) of 1.9 (95% confidence interval [95% CI] 1.6-2.3) (P < 0.0001). Association with case status reached P < 0.05 for both the central femur (OR 1.8 [95% CI 1.5-2.2]) and the central tibia (OR 1.6 [95% CI 1.3-1.9]). Lateral femorotibial compartment cartilage thickness loss, in contrast, was not significantly associated with case status. A reduction in central medial femorotibial compartment cartilage thickness was strongly associated with radiographic progression (OR 4.0 [95% CI 2.9-5.3]; P < 0.0001) and only weakly associated with pain progression (OR 1.3 [95% CI 1.1-1.6]; P < 0.01).

CONCLUSION

Our findings indicate that loss of medial femorotibial cartilage thickness over 24 months is associated with the combination of radiographic and pain progression in the knee, with a stronger association for radiographic progression.

Characterisation of bacteria in ascites--reporting the potential of culture-independent, molecular analysis

Spontaneous bacterial peritonitis (SBP) is a severe complication of liver disease. A significant proportion of patients have culture-negative ascites, despite having similar signs, symptoms and mortality to those with SBP. Therefore, empirical antibiotic treatment for infection is often started without knowledge of the causative organisms. Here, we investigated the potential of molecular techniques to provide rapid and accurate characterisation of the bacteria present in ascitic fluid. Ascites samples were obtained from 29 cirrhotic patients undergoing clinically indicated therapeutic paracentesis. Bacterial content was determined by terminal restriction fragment length polymorphism (T-RFLP) analysis, quantitative polymerase chain reaction (PCR) and 16S ribosomal clone sequence analysis. Bacterial signal was detected in all samples, compared to three out of ten using standard methods. Bacterial loads ranged from 5.5 x 10(2) to 5.4 x 10(7) cfu/ml, with a mean value of 1.9 x 10(6) cfu/ml (standard deviation +/- 9.6 x 10(6) cfu/ml). In all but one instance, bacterial species identified by culture were also confirmed by molecular analyses. Preliminary data presented here suggests that culture-independent, molecular analyses could provide rapid characterisation of the bacterial content of ascites fluid, providing a basis for the investigation of SBP development and allowing early and targeted antibiotic intervention.

Common allelic variants of exons 10, 12, and 33 of the thyroglobulin gene are not associated with autoimmune thyroid disease in the United Kingdom

Thyroglobulin (Tg) is a major autoantigen for autoimmune thyroid disease (AITD). The Tg gene (Tg) has been mapped to chromosome 8q24, which has recently been linked in two independent studies to AITD. Association of specific alleles of microsatellite markers within Tg itself supports a role for Tg as a good candidate susceptibility locus for AITD. Resequencing of the Tg exons has led to the identification of a number of novel single nucleotide polymorphisms, four of which have been reported to be associated with AITD. Resequencing of Tg in Caucasian subjects in the United Kingdom (UK) has confirmed the presence of four single nucleotide polymorphisms in exons 10, 12, and 33. However, in the largest case-control association study to date with adequate power to detect the reported effect if present, we found no evidence for association of the Tg DNA variants with AITD in the UK. These data suggest that the recently identified single nucleotide polymorphisms do not have a causal role for AITD in the UK. At this stage, we cannot exclude the Tg region as harboring a susceptibility locus for AITD, and only large scale sequencing and fine mapping of the region, including neighboring genes, will allow us to identify any potential causal variants within this region.

Lack of association of the vitamin D receptor gene with Graves' disease in UK Caucasians

OBJECTIVE

Vitamin D modulates the immune system by suppressing the proliferation of activated T cells, with its actions being directed through the vitamin D receptor (VDR). A number of single nucleotide polymorphisms (SNPs) have been identified in the VDR gene, of which several have been associated with autoimmune diseases, including type 1 diabetes and Graves' disease (GD) in Japanese females. The aim of this study was to test for association of polymorphisms of the VDR gene in the genetic susceptibility to GD in UK Caucasians.

DESIGN

Target DNA for five previously published SNPs, four novel SNPs and one microsatellite marker was amplified by the polymerase chain reaction (PCR). Subsequent genotyping was performed using restriction fragment length polymorphism (RFLP) or microsatellite genotyping analysis, according to the type of VDR polymorphism.

PATIENTS

We obtained DNA from a case-control dataset consisting of 768 patients with GD and 864 control subjects. All patients and control subjects were Caucasians born in the UK, and all gave informed, written consent.

MEASUREMENTS

Frequencies of the alleles and genotypes of the ten VDR gene polymorphisms were compared between patients and control subjects using the chi2 test. Odds ratios were calculated using Woolf's method with Haldane's modification for small numbers and D prime (D') was calculated to assess the level of linkage disequilibrium (LD) between the ten polymorphisms.

RESULTS

No differences in allele or genotype frequencies were observed between GD cases and control subjects for any of the nine SNPs studied. The S allele of the PolyA microsatellite marker was slightly more frequent in GD cases when compared with control subjects (chi2= 4.364, P = 0.04). Strongest LD between markers was observed towards the 3' end of the VDR gene but there was no evidence of association with disease.

CONCLUSION

This is the largest and most comprehensive study of the VDR gene in GD to date and these data suggest that these polymorphisms of the VDR gene do not contribute to GD susceptibility in the UK.

The DNA sequence and analysis of human chromosome 13

Chromosome 13 is the largest acrocentric human chromosome. It carries genes involved in cancer including the breast cancer type 2 (BRCA2) and retinoblastoma (RB1) genes, is frequently rearranged in B-cell chronic lymphocytic leukaemia, and contains the DAOA locus associated with bipolar disorder and schizophrenia. We describe completion and analysis of 95.5 megabases (Mb) of sequence from chromosome 13, which contains 633 genes and 296 pseudogenes. We estimate that more than 95.4% of the protein-coding genes of this chromosome have been identified, on the basis of comparison with other vertebrate genome sequences. Additionally, 105 putative non-coding RNA genes were found. Chromosome 13 has one of the lowest gene densities (6.5 genes per Mb) among human chromosomes, and contains a central region of 38 Mb where the gene density drops to only 3.1 genes per Mb.

Evidence for a Type 1 diabetes-specific mechanism for the insulin gene-associated IDDM2 locus rather than a general influence on autoimmunity

AIMS

The Type 1 diabetes susceptibility locus, IDDM2, has been mapped to a variable number of tandem repeats (VNTR) region 5' upstream of the insulin (INS) and insulin-like growth factor (IGF2) genes on chromosome 11p15. The function of the VNTR is uncertain; however, it may influence the thymic expression of the insulin gene and affect the development of immune self-tolerance. The aim of this study was to investigate whether the INS VNTR region is a Type 1 diabetes-specific locus or acting as a general autoimmunity gene.

METHODS

We genotyped the INS-IGF2 VNTR [using the surrogate INS-23 HphI single nucleotide polymorphism (SNP)] in 823 Graves' disease (GD)/multiple sclerosis (MS) families, 1433 GD/MS patients and 837 healthy control subjects.

RESULTS

We found no evidence of excess transmission of the allele associated with Type 1 diabetes to individuals affected by GD or MS within the families. Analysis of the case-control dataset showed no genotypic or allelic difference between the two populations.

CONCLUSIONS

These data suggest that the INS-IGF2 VNTR is acting as a Type 1 diabetes-specific susceptibility gene rather than as an influence on general autoimmunity.

Cadherins, catenins and APC in pleural malignant mesothelioma

Malignant mesothelioma is an aggressive disease of the pleura, and less commonly the peritoneum, with a very poor prognosis. The present study has examined the expression of cell adhesion molecules including cadherins, catenins, and APC in order to determine whether abnormal expression of components of the Wnt signalling pathway contribute to the variable phenotype of malignant mesothelioma. Sixty-three malignant mesotheliomas and nine cases of reactive mesothelial hyperplasia were analysed by immunohistochemistry for E-cadherin, N-cadherin, alpha-catenin, beta-catenin, and the C- and N-terminals of APC. In addition, DNA was extracted from formalin-fixed, paraffin wax blocks, and a 226 bp fragment of exon 3 of the beta-catenin gene was amplified, sequenced, and screened for activating mutations in the glycogen synthase kinase 3beta (GSK-3beta) phosphorylation targets. E-cadherin expression was detected in 48% of the epithelioid mesotheliomas but was observed in only 7% of sarcomatoid mesotheliomas. N-cadherin, alpha-catenin, beta-catenin, and the C- and N-terminals of APC did not show differential expression between the mesothelioma phenotypes. Abnormal nuclear localization of beta-catenin was demonstrated in 19% of mesotheliomas. Mutations of beta-catenin phosphorylation sites were not detected in any of the 62 mesotheliomas examined. Positive staining for the N-terminal of APC was seen in all of the cases of reactive mesothelial hyperplasia, as well as in all the mesotheliomas. Staining for the C-terminal of APC was negative in 23% mesotheliomas, despite being present in all the cases of reactive hyperplasia. The present study provides the first evidence that beta-catenin accumulates in the nucleus in malignant mesotheliomas. In addition, APC expression was altered in some mesotheliomas, suggesting that a truncated APC gene product may contribute to abnormal Wnt signalling and dysregulation of cell proliferation in malignant mesothelioma.

The DNA sequence and analysis of human chromosome 6

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Association of a rare thyroglobulin gene microsatellite variant with autoimmune thyroid disease

Genetic and environmental factors contribute to the development of Graves' disease and Hashimoto's thyroiditis. These diseases, although clinically distinct, share many immunological and histological features. Susceptibility genes for autoimmune thyroid disease (AITD) have been investigated, although only the human leukocyte antigen and cytotoxic T lymphocyte-associated antigen-4 gene regions have been consistently associated with disease. Recent data, however, have shown linkage and association of chromosome 8q24 (containing the thyroglobulin gene) to AITD. Therefore, we performed a case-control association study on patients with AITD and controls using previously associated markers (D8S284 and Tgms2). No differences in allele frequencies were observed between AITD cases and controls for D8S284. Compared with the three common alleles (frequencies >10%), the rare alleles of Tgms2 were increased (chi(2)= 10.6; P = 0.001) at Tgms2. This group included the 336-bp allele (increased in cases vs. controls: chi(2)= 24.97; P < 0.001), which has previously been reported to be associated with AITD. The rarity of this allele in the United Kingdom, however, precluded analysis in our family dataset. Although these findings may represent a random chance event, in view of previous reports of linkage and association of this gene region to AITD, this may be an example of a rare causal variant of a complex disease.

Transmission of porcine reproductive and respiratory syndrome virus from persistently infected sows to contact controls

The objective of this study was to determine if porcine reproductive and respiratory syndrome virus (PRRSV) could persist in non-pregnant sows and if persistently infected sows could transmit virus to naive contact controls. Twelve PRRSV-naive, non-pregnant sows (index sows) were infected with a field isolate of PRRSV and housed in individual isolation rooms for 42 to 56 days postinfection. Following this period, 1 naive contact sow was placed in each room divided by a gate allowing nose-to-nose contact with a single index sow. Index sows were not viremic at the time of contact sow entry. Virus nucleic acid was detected by polymerase chain reaction, and infectious virus was detected by virus isolation in sera from 3 of the 12 contact sows at 49, 56, and 86 days postinfection. All 3 infected contacts developed PRRSV antibodies. Virus nucleic acid was detected in tissues of all of the 12 index sows at 72 or 86 days postinfection. Nucleic acid sequencing indicated that representative samples from index and infected contacts were homologous (> 99%) to the PRRSV used to infect index sows at the onset of the study. This study demonstrates that PRRSV can persist in sows and that persistently infected sows can transmit virus to naive contact animals.

Diagnostic investigation of chronic porcine reproductive and respiratory syndrome virus in a breeding herd of pigs

Forty-five sows and 15 boars were selected at random from a breeding herd known to be chronically infected with porcine reproductive and respiratory syndrome virus (PRRSV) and lymphoid, immune-privileged, and non-lymphoid/non-immune-privileged tissues were tested for the presence of the virus by PCR, virus isolation, and immunohistochemistry. The virus was isolated from the lateral retropharyngeal lymph node of one sow; the isolate was nucleic acid sequenced and determined to be of field origin, and it was inoculated into two PRRSV-naive pregnant sows (A and B) at 95 days of gestation. They were necropsied 14 days later and samples of maternal and fetal tissue and blood samples were collected. Sow A had 10 fresh, six partially autolysed, and two mummified fetuses, and sow B had six fresh and viable fetuses. Viral nucleic acid was detected by PCR in tissue pools from each sow and also from pooled fetal tissues, and the virus was isolated from fetal pools from sow A.

CD8+ T cells in human uterine endometrial lymphoid aggregates: evidence for accumulation of cells by trafficking

Lymphoid aggregates (LA) develop during the proliferative phase of the menstrual cycle in the human uterine endometrium (EM). They contain mostly CD8+ T cells and B cells. As these LA are absent immediately following menses, they may arise by division of cells resident in the EM, or by division of a limited number of precursor cells that traffic into the EM during the early proliferative phase of the menstrual cycle. Alternatively, they may arise by the continuous trafficking of cells into the EM throughout the proliferative phase of the menstrual cycle. In this study we investigated the distribution and frequency of CD8+ T cells in the aggregates using expression of Vbeta2 or Vbeta8 as markers of clonality and Ki-67 as a marker of dividing cells. Confocal microscopic analysis of endometrial tissues showed the random distribution of CD8+ T cells within aggregates within the same sample and in aggregates from different samples. Furthermore, comparisons of the distribution of Vbeta2 and Vb8 with expected values predicted from Poisson distribution values were not significantly different, suggesting that CD8+ T cells do not arise by division from single precursors. A low level of T-cell division within LAs was confirmed by positive staining for Ki-67. Dividing T cells were randomly dispersed throughout the LA and the frequency of dividing cells did not vary greatly between aggregates within the same tissue. Nearest-neighbour analysis of dividing cells showed no statistically significant deviations from a random distribution. Taken together, these results suggest that LA develop during the menstrual cycle largely by the trafficking of cells to nucleation sites within the EM, rather than by division of a limited number of precursor cells.

The physical maps for sequencing human chromosomes 1, 6, 9, 10, 13, 20 and X

We constructed maps for eight chromosomes (1, 6, 9, 10, 13, 20, X and (previously) 22), representing one-third of the genome, by building landmark maps, isolating bacterial clones and assembling contigs. By this approach, we could establish the long-range organization of the maps early in the project, and all contig extension, gap closure and problem-solving was simplified by containment within local regions. The maps currently represent more than 94% of the euchromatic (gene-containing) regions of these chromosomes in 176 contigs, and contain 96% of the chromosome-specific markers in the human gene map. By measuring the remaining gaps, we can assess chromosome length and coverage in sequenced clones.

Insertional events as well as translocations may arise during aberrant immunoglobulin switch recombination in a patient with multiple myeloma

The majority of patients with multiple myeloma have translocations involving the immunoglobulin heavy chain switch regions on chromosome 14q32 and a promiscuous range of partner chromosomes. We describe a patient with an insertion of 132 bp of chromosome 22q12 sequence into the 5' region flanking S(mu) on chromosome 14q32. The 132 bp region from chromosome 22q12 contains the whole of exon 3 from a novel gene of unknown function in man. The significance of such insertional events remains unclear. The description of insertional events occurring as a result of abnormal switch recombination suggests that, in myeloma, dysregulation of oncogenes may occur by a mechanism other than chromosomal translocation.

MHC class II expression and antigen presentation by human endometrial cells

It has been demonstrated previously that mixed cell suspensions from the female reproductive tract consisting of human epithelial and stromal cells were capable of presenting foreign antigen to autologous T cells. There have been, however, no reported studies examining antigen presentation by isolated epithelial cells from the human female reproductive tract. It is now shown that freshly isolated epithelial cells from the uterine endometrium constitutively express MHC class II antigen and that class II was upregulated on cultured epithelium by interferon gamma (IFNgamma). Using a highly purified preparation, it was demonstrated that these epithelial cells were able to process and present tetanus toxoid recall antigen driving autologous T cell proliferation. Cells isolated from the basolateral sub-epithelium stroma were also potent antigen presenting cells in this model system. Thus, isolated endometrial epithelial cells were able to directly process and present antigen to T cells and may be responsible for the transcytosis and delivery of antigen to professional antigen presenting cells found in the sub-epithelial stroma.

Correlation between the presence of enzootic pneumonia lesions and detection of Mycoplasma hyopneumoniae in bronchial swabs by PCR

In many diagnostic laboratories the diagnosis of mycoplasmal pneumonia in pigs is based on clinical signs and the presence of gross and histopathological lesions. The objective of this study was to evaluate the nested-PCR technique as an adjunct to the histopathological diagnosis of Mycoplasma hyopneumoniae infection. Respiratory disease of 184 swine cases submitted to the Minnesota Veterinary Diagnostic Laboratory between 1 January and 30 June 1998 were used. Bronchial swabs were collected and the nested-PCR performed. Lung samples were graded PCR positive or negative. Histopathological lesions were scored 0-4, depending on the mycoplasma-like characteristics of the lesions, with category 4 demonstrating strong evidence of mycoplasma infection.Nested-PCR correlated well with histopathological lesions characteristic of M. hyopneumoniae in categories 3 and 4 and approximately half of the histopathological categories 1 and 2 were nested-PCR positive. The results demonstrate that the nested-PCR is a valuable adjunct in the diagnosis of M. hyopneumoniae infection when non-diagnostic microscopic lesions of mycoplasmosis are found.

Muscle force and range of motion as predictors of function in older adults

BACKGROUND AND PURPOSE

Musculoskeletal impairments and functional limitations are linked to disability in older adults. The purposes of this study were to identify the extremity musculoskeletal impairments that best predict functional limitations in older adults and to assess the validity of measurements obtained for the Physical Performance Test (PPT) as a predictor of disability.

SUBJECTS AND METHODS

Eighty-one older adults residing in independent and dependent care facilities were tested for extremity muscle force, range of motion, and function. Data were analyzed using multiple regression analysis to identify extremity impairments that predicted function scores and logistic regression analysis to determine whether PPT scores predicted subjects' living situation as dependent versus independent.

RESULTS

Subject age, lower-extremity muscle force, and lower-extremity range of motion explained 77% of the variance in function as measured by the PPT. Results differed when analysis was done by subject living situation, with a higher percentage of the variance in function scores explained by musculoskeletal measures for the dependent living group as compared with the independent living group.

CONCLUSION AND DISCUSSION

Extremity musculoskeletal impairments have a strong relationship to function, especially in older adults living in dependent care settings. The results of this study can be used to design interventions to address the musculoskeletal disorders most related to function in the older population.

Cloning and expression throughout mouse development of mfat1, a homologue of the Drosophila tumour suppressor gene fat

We present the entire sequence of the mouse Fat orthologue (mFat1), a protein of 4,588 amino acids with 34 cadherin repeats, 27 potential N-glycosylation sites, five EGF repeats and a laminin A G-motif in its extracellular domain. A single transmembrane region is followed by a cytoplasmic domain containing putative catenin-binding sequences. mFat1 shows high homology to human FAT and lesser homology to Drosophila Fat. The sequence of this giant cadherin suggests that it is unlikely to have a homophilic adhesive function, but may mediate heterophilic adhesion or play a signalling role. Expression analysis shows that the mfat1 gene is expressed early in pre-implantation mouse development, at the compact eight cell stage. Whole-mount and section in situ analyses show that transcripts are widely expressed throughout post-implantation development, most notably in the limb buds, branchial arches, forming somites, and in particular in the proliferating ventricular zones in the brain, being down-regulated as cells cease dividing. RT-PCR detects widespread expression in the adult suggesting a role in proliferation and differentiation of many tissues and cell types.

The DNA sequence of human chromosome 22

Knowledge of the complete genomic DNA sequence of an organism allows a systematic approach to defining its genetic components. The genomic sequence provides access to the complete structures of all genes, including those without known function, their control elements, and, by inference, the proteins they encode, as well as all other biologically important sequences. Furthermore, the sequence is a rich and permanent source of information for the design of further biological studies of the organism and for the study of evolution through cross-species sequence comparison. The power of this approach has been amply demonstrated by the determination of the sequences of a number of microbial and model organisms. The next step is to obtain the complete sequence of the entire human genome. Here we report the sequence of the euchromatic part of human chromosome 22. The sequence obtained consists of 12 contiguous segments spanning 33.4 megabases, contains at least 545 genes and 134 pseudogenes, and provides the first view of the complex chromosomal landscapes that will be found in the rest of the genome.

Psoriasis upregulated phorbolin-1 shares structural but not functional similarity to the mRNA-editing protein apobec-1

Earlier studies of psoriatic and normal primary keratinocytes treated with phorbol 12-myristate-1-acetate identified two low-molecular-weight proteins, termed phorbolin-1 (20 kDa; pI 6.6) and phorbolin-2 (17.6 kDa; pI 6.5). As a first step towards elucidating the role of these proteins in psoriasis, we report here the molecular cloning and chromosomal mapping of phorbolin-1 and a related cDNA that codes for a protein exhibiting a similar amino acid sequence. The phorbolins were mapped to position 22q13 immediately centromeric to the c-sis proto-oncogene. Transient expression of the phorbolin-1 cDNA in COS cells and by in vitro transcription/translation, yielded polypeptides that comigrated with phorbolins-1 and -2. Comparative sequence analysis revealed 22% overall identity and a similarity of 44% of the phorbolins to apobec-1, the catalytic subunit of the mammalian apolipoprotein B mRNA editing enzyme; however, recombinant-expressed phorbolin-1 exhibited no cytidine deaminase activity, using either a monomeric nucleoside or apolipoprotein B cRNA as substrate, and failed to bind an AU-rich RNA template. Whereas the precise function of the phorbolins remains to be elucidated, the current data suggest that it is unlikely to include a role in the post-transcriptional modification of RNA in a manner analogous to that described for apobec-1.

Outcome of medium chain acyl-CoA dehydrogenase deficiency after diagnosis

BACKGROUND

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common inborn error of fatty acid metabolism. Undiagnosed, it has a mortality rate of 20-25%. Neonatal screening for the disorder is now possible but it is not known whether this would alter the prognosis.

OBJECTIVE

To investigate the outcome of MCAD deficiency after the diagnosis has been established.

METHOD

All patients with a proved diagnosis of MCAD deficiency attending one centre in a four year period were reviewed.

RESULTS

Forty one patients were identified. Follow up was for a median of 6.7 years (range, 9 months to 14 years). Nearly half of the patients were admitted to hospital with symptoms characteristic of MCAD deficiency before the correct diagnosis was made. After diagnosis, two patients were admitted to hospital with severe encephalopathy but there were no additional deaths or appreciable morbidity. There was a high incidence (about one fifth) of previous sibling deaths among the cohort.

CONCLUSIONS

Undiagnosed, MCAD deficiency results in considerable mortality and morbidity. However, current management improves outcome, supporting the view that the disorder should be included in newborn screening programmes.

Porcine reproductive and respiratory syndrome virus infection in neonatal pigs characterised by marked neurovirulence

Neonatal pigs from three herds of pigs were somnolent and inappetent and had microscopic lesions characterised by severe meningoencephalitis, necrotic interstitial pneumonia and gastric muscular inflammation. Porcine reproductive and respiratory syndrome virus (PRRSV) infection was diagnosed and confirmed by virus isolation, fluorescent antibody examination of frozen lung sections, serology, immunohistochemistry and in situ hybridisation. Each herd had a history of PRRSV infection and was using or had used a modified-live vaccine. The isolates from the affected pigs were genetically distinct from the modified-live vaccine strain of the virus when compared by restriction enzyme analysis and nucleotide sequencing of PRRSV open reading frames 5 and 6. The virus was identified in macrophages or microglia of brain lesions by immunohistochemical staining of brain sections with an anti-PRRSV monoclonal antibody and an anti-macrophage antibody. The replication of the virus in the brain was verified by in situ hybridisation. The meningoencephalitis induced by the virus in pigs from each of the herds was unusually severe and the brain lesions were atypical when compared with other descriptions of encephalitis induced by the virus, which should therefore be considered as a possible diagnosis for neonatal pigs with severe meningoencephalitis. In addition, field isolates of the virus which are capable of causing disease can emerge and coexist with modified-live vaccine virus in some pig herds.

Characterization of the human synaptogyrin gene family

Genomic sequencing was combined with searches of databases for identification of active genes on human chromosome 22. A cosmid from 22q13, located in the telomeric vicinity of the PDGFB (platelet-derived growth factor B-chain) gene, was fully sequenced. Using an expressed sequence tag-based approach we characterized human (SYNGR1) and mouse (Syngr1) orthologs of the previously cloned rat synaptogyrin gene (RATSYNGR1). The human SYNGR1 gene reveals three (SYNGR1a, SYNGR1b, SYNGR1c) alternative transcript forms of 4.5, 1.3 and 0.9 kb, respectively. The transcription of SYNGR1 starts from two different promoters, and leads to predicted proteins with different N- and C-terminal ends. The most abundant SYNGR1 a transcript, the 4.5-kb form, which corresponds to RATSYNGR1, is highly expressed in neurons of the central nervous system and at much lower levels in other tissues, as determined by in situ hybridization histochemistry. The levels of SYNGR1b and SYNGR1c transcripts are low and limited to heart, skeletal muscle, ovary and fetal liver. We also characterized two additional members of this novel synaptogyrin gene family in human (SYNGR2 and SYNGR3), and one in mouse (Syngr2). The human SYNGR2 gene transcript of 1.6 kb is expressed at high levels in all tissues, except brain. The 2.2-kb SYNGR3 transcript was detected in brain and placenta only. The human SYNGR2 and SYNGR3 genes were mapped by fluorescence in situ hybridization to 17qtel and 16ptel, respectively. The human SYNGR2 gene has a processed pseudogene localized in 15q11. All predicted synaptogyrin proteins contain four strongly conserved transmembrane domains, which is consistent with the M-shaped topology. The C-terminal polypeptide ends are variable in length, display a low degree of sequence similarity between family members, and are therefore likely to convey the functional specificity of each protein.