Diffusible, nonfibrillar ligands derived from Abeta1-42 are potent central nervous system neurotoxins

Abeta1-42 is a self-associating peptide whose neurotoxic derivatives are thought to play a role in Alzheimer's pathogenesis. Neurotoxicity of amyloid beta protein (Abeta) has been attributed to its fibrillar forms, but experiments presented here characterize neurotoxins that assemble when fibril formation is inhibited. These neurotoxins comprise small diffusible Abeta oligomers (referred to as ADDLs, for Abeta-derived diffusible ligands), which were found to kill mature neurons in organotypic central nervous system cultures at nanomolar concentrations. At cell surfaces, ADDLs bound to trypsin-sensitive sites and surface-derived tryptic peptides blocked binding and afforded neuroprotection. Germ-line knockout of Fyn, a protein tyrosine kinase linked to apoptosis and elevated in Alzheimer's disease, also was neuroprotective. Remarkably, neurological dysfunction evoked by ADDLs occurred well in advance of cellular degeneration. Without lag, and despite retention of evoked action potentials, ADDLs inhibited hippocampal long-term potentiation, indicating an immediate impact on signal transduction. We hypothesize that impaired synaptic plasticity and associated memory dysfunction during early stage Alzheimer's disease and severe cellular degeneration and dementia during end stage could be caused by the biphasic impact of Abeta-derived diffusible ligands acting upon particular neural signal transduction pathways.

Isolation and identification of methanogen-specific DNA from blanket bog peat by PCR amplification and sequence analysis

The presence of methanogenic bacteria was assessed in peat and soil cores taken from upland moors. The sampling area was largely covered by blanket bog peat together with small areas of red-brown limestone and peaty gley. A 30-cm-deep core of each soil type was taken, and DNA was extracted from 5-cm transverse sections. Purified DNA was subjected to PCR amplification with primers IAf and 1100Ar, which specifically amplify 1.1 kb of the archaeal 16S rRNA gene, and ME1 and ME2, which were designed to amplify a 0.75-kb region of the alpha-subunit gene for methyl coenzyme M reductase (MCR). Amplification with both primer pairs was obtained only with DNA extracted from the two deepest sections of the blanket bog peat core. This is consistent with the notion that anaerobiosis is required for activity and survival of the methanogen population. PCR products from both amplifications were cloned, and the resulting transformants were screened with specific oligonucleotide probes internal to the MCR or archaeal 16S rRNA PCR product. Plasmid DNA was extracted from probe-positive clones of both types and the insert was sequenced. The DNA sequences of 8 MCR clones were identical, as were those of 16 of the 17 16S rRNA clones. One clone showed marked variation from the remainder in specific regions of the sequence. From a comparison of these two different 16S rRNA sequences, an oligonucleotide was synthesized that was 100% homologous to a sequence region of the first 16 clones but had six mismatches with the variant. This probe was used to screen primary populations of PCR clones, and all of those that were probe negative were checked for the presence of inserts, which were then sequenced. By using this strategy, further novel methanogen 16S rRNA variants were identified and analyzed. The sequences recovered from the peat formed two clusters on the end of long branches within the methanogen radiation that are distinct from each other. These cannot be placed directly with sequences from any cultured taxa for which sequence information is available.

Extraction and high-performance liquid chromatographic method for the determination of microcystins in raw and treated waters

Increasing concern over the presence of microcystins (cyanobacterial/blue-green algal hepatotoxins) in water supplies has emphasized the need for a suitable analytical method. As many microcystins are known to exist, a method was developed that permits the determination of numerous variants by a single procedure. The method involves filtration to separate cyanobacterial cells from water, allowing intracellular and extracellular toxin levels to be assessed. The cellular components of the samples are extracted repeatedly in methanol, which was found to be the most versatile solvent tested for the extraction of microcystins. The efficiency of this extraction procedure was found to be independent of cell biomass. The filtered water was subjected to trace enrichment using a C18 solid-phase extraction cartridge, followed by identification and determination by photodiode-array high-performance liquid chromatography. The procedure was assessed using four water samples (two raw and two treated) spiked with a mixture of five microcystins and the cyanobacterial hepatotoxin nodularin. Recoveries of all but one microcystin were found to be good when spiked with concentrations as low as 250 ng l-1. The linearity and precision of the experimental procedure were assessed for five microcystins and nodularin. The proposed method permits rapid sample processing and determination of several microcystins.

Human reserve pluripotent mesenchymal stem cells are present in the connective tissues of skeletal muscle and dermis derived from fetal, adult, and geriatric donors

This study details the profile of 13 cell surface cluster differentiation markers on human reserve stem cells derived from connective tissues. Stem cells were isolated from the connective tissues of dermis and skeletal muscle derived from fetal, mature, and geriatric humans. An insulin/dexamethasone phenotypic bioassay was used to determine the identity of the stem cells from each population. All populations contained lineage-committed myogenic, adipogenic, chondrogenic, and osteogenic progenitor stem cells as well as lineage-uncommitted pluripotent stem cells capable of forming muscle, adipocytes, cartilage, bone, fibroblasts, and endothelial cells. Flow cytometric analysis of adult stem cell populations revealed positive staining for CD34 and CD90 and negative staining for CD3, CD4, CD8, CD11c, CD33, CD36, CD38, CD45, CD117, Glycophorin-A, and HLA DR-II.

The Maudsley Addiction Profile (MAP): a brief instrument for assessing treatment outcome

AIM

To develop a brief, multi-dimensional instrument for assessing treatment outcome for people with drug and/or alcohol problems. The Maudsley Addiction Profile (MAP) is the first instrument to be developed in the United Kingdom for this purpose.

DESIGN

Field testing with quota-recruitment of problem drug users and problem alcohol users in treatment with researcher and clinician-administered test-retest interviews.

SETTING

Two community and two inpatient services at the Bethlem Royal and Maudsley Hospital, London.

PARTICIPANTS

Subjects (160 drug users and 80 alcohol users) interviewed by eight interviews (four researchers and four clinicians), each of whom interviewed 30 subjects on two occasions.

MEASURES

Sixty items across substance use, health risk, physical/psychological health and personal/social functioning domains.

FINDINGS

Average completion time of the MAP was 12 minutes. The questionnaire was acceptable to a majority of subjects and performed well with both researcher and clinician interviewers. Internal reliability and feasible concurrent validity assessments of the scales and items were highly satisfactory. Test-retest reliability was good, average intraclass correlation coefficients across eight substances were 0.94 and 0.81 across health risk, health problems, relationship conflict, employment and crime measures.

CONCLUSIONS

The MAP can serve as a core research instrument with additional outcome measures added as required. The collection of a set of reliable quantitative measures of problems among drug and alcohol users by research or treatment personnel for outcome evaluation purposes need not be time-consuming.

Diagnosing and managing unstable angina. Agency for Health Care Policy and Research

This Quick Reference Guide for Clinicians contains recommendations on the care of patients with unstable angina based on a combination of evidence obtained through extensive literature reviews and consensus among members of an expert panel. Principal conclusions include the following. (1) Many patients suspected of having unstable angina can be discharged home after adequate initial evaluation. (2) Further outpatient evaluation may be scheduled for up to 72 hours after initial presentation for patients with clinical symptoms of unstable angina judged at initial evaluation to be at low risk for complications. (3) Patients with acute ischemic heart disease judged to be at intermediate or high risk of complications should be hospitalized for careful monitoring of their clinical course. (4) Intravenous thrombolytic therapy should not be administered to patients without evidence of ST segment elevation and acute myocardial infarction. (5) Assessment of prognosis by noninvasive testing often aids selection of appropriate therapy. (6) Coronary angiography is appropriate for patients judged to be at high risk for cardiac complications or death based on their clinical course or results of noninvasive testing. (7) Coronary artery bypass surgery should be recommended for almost all patients with left main disease and many patients with three-vessel disease, especially those with left ventricular dysfunction. (8) The discharge care plan should include continued monitoring of symptoms; appropriate drug therapy, including aspirin; risk-factor modification; and counseling.

Three-dimensional cellular development is essential for ex vivo formation of human bone

Tissue engineering of human bone is a complex process, as the functional development of bone cells requires that regulatory signals be temporally and spatially ordered. The role of three-dimensional cellular interactions is well understood in embryonic osteogenesis, but in vitro correlates are lacking. Here we report that in vitro serum-free transforming growth factor (TGF)-beta1 stimulation of osteogenic cells immediately after passage results in the formation of three-dimensional cellular condensations (bone cell spheroids) within 24 to 48 hours. In turn, bone cell spheroid formation results in the up-regulation of several bone-related proteins (e.g., alkaline phosphatase, type I collagen, osteonectin) during days 3-7, and the concomitant formation of micro-crystalline bone. This system of ex vivo bone formation should provide important information on the physiological, biological and molecular basis of osteogenesis.

Identification of anatoxin-A in benthic cyanobacteria (blue-green algae) and in associated dog poisonings at Loch Insh, Scotland

Dog deaths occurred in 1990 and 1991 after the animals drank water containing blooms of benthic cyanobacteria along the shoreline of Loch Insh, Scotland. Signs of poisoning in the affected animals and the high neurotoxicity of bloom extracts in laboratory bioassays indicated acute poisoning due to cyanobacterial neurotoxin(s). The neurotoxic blooms consisted largely of benthic Oscillatoria species which were also observed in the stomach contents of the poisoned dogs. Stomach contents were also neurotoxic in bioassays with the same signs of poisoning as the Oscillatoria blooms. The cyanobacterial alkaloid neurotoxin anatoxin-a was identified in bloom extracts and poisoned dog stomach contents by high-performance liquid chromatography and gas chromatography-mass spectrometry. A species of benthic Oscillatoria has been isolated from the neurotoxic bloom material and shown to produce anatoxin-a in laboratory culture. These findings are the first to associate anatoxin-a toxicoses with benthic, rather than planktonic, cyanobacteria. Procedures for anatoxin-a extraction and identification from the blooms and animal material are also detailed.

Congenital absence of the vagina. The Mayer-Rokitansky-Kuster-Hauser syndrome

We describe 14 patients with congenital absence of the vagina associated with a variable abnormality of the uterus and review the literature. Associated developmental anomalies of the urinary tract and skeleton are common. As a result of the analysis of two affected families, we believe that the disorder may represent the variable manifestation of a single underlying genetic defect that can be expressed alone or in any combination of vertebral, renal, and genital abnormalities. Some affected persons may have lethal manifestations such as absence of both kidneys, and some cases may result from multifactoral causes rather than a single gene defect. Whatever the cause, the defect involves mesodermal development and the mesonephric kidney, the latter resulting in abnormalities in the paramesonephros (uterus and vagina) and in the metanephric kidney. Both nonoperative and surgical treatments are generally successful in repairing the vaginal abnormality.

Patients with t(8;21)(q22;q22) and acute myeloid leukemia have superior failure-free and overall survival when repetitive cycles of high-dose cytarabine are administered

PURPOSE

To examine the effect of single compared with repetitive (at least three) cycles of high-dose cytarabine after induction therapy for patients with acute myeloid leukemia (AML) who have the t(8;21)(q22;q22) karyotype.

PATIENTS AND METHODS

Patients entered onto the study had AML and t(8;21) and attained a complete remission on four successive Cancer and Leukemia Group B studies. In these studies, either > or = three cycles of high-dose cytarabine or one cycle of high-dose cytarabine was administered, followed by sequential cyclophosphamide/etoposide and mitoxantrone/diaziquone with or without filgrastim support. Outcomes of these two groups of t(8;21) patients were compared.

RESULTS

A total of 50 patients with centrally reviewed AML and t(8;21) were assigned to receive one (n = 29) or > or = three cycles (n = 21) of high-dose cytarabine as postinduction therapy. The clinical features of these two groups of patients were similar. Initial remission duration for t(8;21) patients assigned to one cycle of high-dose cytarabine was significantly inferior (P =.03), with 62% of patients experiencing relapse with a median failure-free survival of 10.5 months, compared with the group of patients who received > or = three cycles, in which only 19% experienced relapse and failure-free survival is estimated to be greater than 35 months. Furthermore, overall survival was also significantly compromised (P =.04) in patients assigned to one cycle of high-dose cytarabine, with 59% having died as a consequence of AML, compared with 24% of those who received > or = three cycles of high-dose cytarabine.

CONCLUSION

These data demonstrate that failure-free survival and overall survival of patients with t(8;21)(q22;q22) may be compromised by treatment approaches that do not include sequential high-dose cytarabine therapy.

Acarbose. A preliminary review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential

Acarbose delays the production of monosaccharides (notably glucose) by inhibiting the alpha-glucosidases associated with the brush-border membrane of the small intestine which are responsible for the digestion of complex polysaccharides and sucrose. In healthy subjects acarbose 100 to 200 mg significantly inhibits postprandial glucose, insulin and triglyceride responses, with some evidence of carbohydrate malabsorption with the higher dose. Clinical trials in patients with non-insulin-dependent diabetes mellitus showed that acarbose improved diabetic control, especially postprandial blood glucose levels, independent of whether the patients were receiving concomitant oral antidiabetic drugs in addition to dietary management. In comparative studies acarbose was significantly superior to placebo, and comparable to biguanides, when used alone or as an adjuvant to sulphonylurea therapy. Trials in patients requiring insulin to control their diabetes demonstrated that acarbose significantly reduced postprandial blood glucose concentrations, resulting in a smoother diurnal blood glucose-time curve and improved symptoms associated with nocturnal hypoglycaemia. Daily insulin requirements were sometimes reduced. In large multicentre trials acarbose up to 600 mg/day for 3 to 12 months improved glycaemic control in approximately 55% of patients with non-insulin-dependent or insulin-dependent diabetes mellitus. Apart from its use in diabetes, encouraging preliminary results have been obtained with acarbose in other therapeutic areas such as dumping syndrome, reactive hypoglycaemia, and types IIb and IV hyperlipoproteinaemias--however, further clinical experience is needed in these settings before clear conclusions can be drawn. No serious side effects have been reported during treatment with acarbose, although it is associated with a high incidence of troublesome gastrointestinal symptoms such as flatulence, abdominal distension, borborygmus and diarrhoea. The incidence of these reactions usually decreases with time. Thus, acarbose represents the first of a new class of oral antidiabetic drugs--the alpha-glucosidase inhibitors. It has proven useful for improving glycaemic control when used as an adjunct to standard therapy involving dietary restriction, oral antidiabetic drugs and/or subcutaneous insulin. That being the case, acarbose should provide the clinician with an interesting treatment option which can be used in a broad range of patients with diabetes mellitus in whom 'traditional' management approaches produce suboptimal glycaemic control.

Parental perceptions of overweight in 3-5 y olds

OBJECTIVE

To assess the accuracy of parents' perceptions of their 3 to 5 y old children's weight status in a large UK sample.

METHOD

Parental perception and concern about child weight, demographic variables, and children's height and weight were obtained for 564 parent-child dyads.

RESULTS

Only 1.9% of parents of overweight children and 17.1% of parents of obese children described their child as overweight. The odds of parents perceiving the child as overweight were increased for overweight (2.7; 95% CI 0.4, 16.5) and obese (28.5; 7.1, 115.4) compared with normal weight children, but were not associated with parental weight or with any demographic factors. Although few parents perceived their overweight children as overweight, more (66.2%) expressed concern about their overweight child becoming overweight in the future. Odds of concern were progressively higher for overweight (2.5; 1.6, 3.9) and obese children (4.6; 2.2, 9.7), and were also higher for parents who were themselves overweight (1.9; 1.2, 2.9) or obese (2.5; 1.3, 4.8).

CONCLUSION

These findings suggest that parents of 3-5 y olds show poor awareness of their child's current weight status. Reframing discussions in terms of preventing future overweight may be an effective way to engage parents.

Early infection after hip fracture surgery: risk factors, costs and outcome

Prospective data on hip fracture from 3686 patients at a United Kingdom teaching hospital were analysed to investigate the risk factors, financial costs and outcomes associated with deep or superficial wound infections after hip fracture surgery. In 1.2% (41) of patients a deep wound infection developed, and 1.1% (39) had a superficial wound infection. A total of 57 of 80 infections (71.3%) were due to Staphylococcus aureus and 39 (48.8%) were due to MRSA. No statistically significant pre-operative risk factors were detected. Length of stay, cost of treatment and pre-discharge mortality all significantly increased with deep wound infection. The one-year mortality was 30%, and this increased to 50% in those who developed an infection (p < 0.001). A deep infection resulted in doubled operative costs, tripled investigation costs and quadrupled ward costs. MRSA infection increased costs, length of stay, and pre-discharge mortality compared with non-MRSA infection.

Evaluation of biomechanical properties of human skin

Measurement of the physical properties of skin may seem "esoteric" and of little relevance to clinical science; however, the noninvasive nature of available techniques provides unique opportunities for monitoring the effects of disease, drugs, or cosmetics over time on exactly the same area of skin. In vitro testing gives repeatable standardized methods that can supply basic elastic and viscoelastic moduli for skin, which for low strain are comparable to results obtained from in vivo tests. Interpretation of in vivo tests can be difficult, as no analytical model has been developed that can relate measurements from these tests directly to basic skin properties. Each method and each implementation of that method has subtle differences from every other method so that results between studies are difficult to compare; however, the alternative to the bioengineering tests is the hand and eye, which provide subjective (and often biased), nonlinear, and notoriously variable data between individuals. Judging the severity of involvement, the changes due to treatment or progress of disease, and the efficacy of competing treatments is very difficult, even for an experienced clinician. Objective, numerical information on the effects of different active compounds and their formulations is essential if new preparations are to be optimized. Measurement of mechanical properties is one aspect of this important field of endeavor.

An update and guidance on narrowband ultraviolet B phototherapy: a British Photodermatology Group Workshop Report

Summary These guidelines for use of narrowband (TL-01) ultraviolet B have been prepared for dermatologists by the British Photodermatology Group on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment of patients with a variety of dermatoses and photodermatoses, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of background photobiology.

Tissue-specific and light-regulated expression of a pea nuclear gene encoding the small subunit of ribulose-1,5-bisphosphate carboxylase

We have examined the expression of a member of the multigene family encoding the small subunit (rbcS) of ribulose-1,5-bisphosphate carboxylase in various tissues of pea. The rbcS gene, pPS-2.4, was characterized by DNA sequence analysis and 5' and 3' end mapping of its mRNA transcript. rbcS polypeptides were shown to be differentially present in various tissues of light- and dark-grown plants. Northern analysis shows that compared with green leaves, the level of rbcS mRNA is reduced to approximately 50% in pericarps, 8% in petals and seeds, and 1-3% in etiolated leaves, stems, and roots. 5' S1 nuclease mapping of total rbcS mRNA was used to quantitate the relative amount of pPS-2.4 gene-specific transcripts in each tissue. pPS-2.4 mRNA accounts for approximately 30-35% of total rbcS transcripts in green leaves, but only 5-10% in pericarps, 15-20% in seeds, and is below detection in petals and etiolated leaves. We conclude that the pPS-2.4 gene is expressed in a tissue-specific, light-regulated fashion and that transcriptional controls of individual rbcS genes vary.

Ethnic differences in physiological cardiac adaptation to intense physical exercise in highly trained female athletes

BACKGROUND

Ethnicity is an important determinant of cardiovascular adaptation in athletes. Studies in black male athletes reveal a higher prevalence of electric repolarization and left ventricular hypertrophy than observed in white males; these frequently overlap with those observed in cardiomyopathy and have important implications in the preparticipation cardiac screening era. There are no reports on cardiac adaptation in highly trained black females, who comprise an increasing population of elite competitors.

METHODS AND RESULTS

Between 2004 and 2009, 240 nationally ranked black female athletes (mean age 21+/-4.6 years old) underwent 12-lead ECG and 2-dimensional echocardiography. The results were compared with 200 white female athletes of similar age and size participating in similar sports. Black athletes demonstrated greater left ventricular wall thickness (9.2+/-1.2 versus 8.6+/-1.2 mm, P<0.001) and left ventricular mass (187.2+/-42 versus 172.3+/-42 g, P=0.008) than white athletes. Eight black athletes (3%) exhibited a left ventricular wall thickness >11 mm (12 to 13 mm) compared with none of the white athletes. All athletes revealed normal indices of systolic and diastolic function. Black athletes exhibited a higher prevalence of T-wave inversions (14% versus 2%, P<0.001) and ST-segment elevation (11% versus 1%, P<0.001) than white athletes. Deep T-wave inversions (-0.2 mV) were observed only in black athletes and were confined to the anterior leads (V(1) through V(3)).

CONCLUSIONS

Systematic physical exercise in black female athletes is associated with greater left ventricular hypertrophy and higher prevalence of repolarization changes than in white female athletes of similar age and size participating in identical sporting disciplines. However, a maximal left ventricular wall thickness >13 mm or deep T-wave inversions in the inferior and lateral leads are rare and warrant further investigation.

Clinical and economic impact of contaminated blood cultures within the hospital setting

Blood cultures have an important role in the diagnosis of serious infections, although contamination of blood cultures (i.e. false-positive blood cultures) is a common problem within the hospital setting. The objective of the present investigation was to determine the impact of the false-positive blood culture results on the following outcomes: length of stay, hotel costs, antimicrobial costs, and costs of laboratory and radiological investigation. A retrospective case-control study design was used in which 142 false-positive blood culture cases were matched with suitable controls (patients for whom cultures were reported as true negatives). The matching criteria included age, comorbidity score and month of admission to the hospital. The research covered a 13-month period (July 2007 to July 2008). The findings indicated that differences in means, between cases and controls, for the length of hospital stay and the total costs were 5.4 days [95% CI (confidence interval): 2.8-8.1 days; P<0.001] and £5,001.5 [$7,502.2; 95% CI: £3,283.9 ($4,925.8) to £6,719.1 ($10,078.6); P<0.001], respectively. Consequently, and considering that 254 false-positive blood cultures had occurred in the study site hospital over a one-year period, patients with false-positive blood cultures added 1372 extra hospital days and incurred detrimental additional hospital costs of £1,270,381 ($1,905,572) per year. The findings therefore demonstrate that false-positive blood cultures have a significant impact on increasing hospital length of stay, laboratory and pharmacy costs. These findings highlight the need to intervene to raise the standard of blood-culture-taking technique, thus improving both the quality of patient care and resource use.

Purpura and dermal thinning associated with high dose inhaled corticosteroids

OBJECTIVE

To assess the effect of high dose inhaled corticosteroids on skin.

DESIGN

Cross sectional study of patients receiving treatment for chest diseases.

SETTING

Outpatient chest clinic in a teaching hospital.

PATIENTS

68 Patients divided into four groups of similar age--namely, 15 receiving long term oral prednisolone, 21 receiving high dose inhaled corticosteroids, 15 receiving low dose inhaled corticosteroids, and 17 controls.

MAIN OUTCOME MEASURES

Skin thickness at three sites measured by A scan ultrasound and clinical assessment of purpura.

RESULTS

Compared with controls patients in both the oral prednisolone treated group and the high dose inhaled corticosteroid treated group had significantly thinner skin at all three sites (group median thicknesses: prednisolone treated group 28-33% less than controls; high dose inhaled corticosteroid treated group 15-19% less than controls). Differences in skin thicknesses between the low dose inhaled corticosteroid treated group and the controls were trivial. The prevalence of purpura was significantly greater in patients receiving oral prednisolone (12/15 patients) and high dose inhaled corticosteroids (10/21) than in controls (2/17).

CONCLUSION

Skin thinning and purpura represent further evidence of systemic effects of high dose inhaled corticosteroids.

Patterns of expression of tumor necrosis factor alpha, tumor necrosis factor beta, and their receptors in synovia of patients with juvenile rheumatoid arthritis and juvenile spondylarthropathy

OBJECTIVE

To assess the expression of tumor necrosis factor alpha (TNF alpha), TNF beta, and their receptors in synovia of patients with juvenile rheumatoid arthritis (JRA) and juvenile spondylarthropathy (JSpA), and to determine similarities with and differences from adult RA.

METHODS

Twenty-eight synovial tissue samples from patients with JRA, 6 from patients with JSpA, and 6 from patients with RA, selected for the presence of inflammatory infiltrates, were analyzed for the expression of TNF alpha, TNF beta, and their receptors (p55 and p75 TNFR), utilizing the dual approach of reverse transcriptase-polymerase chain reaction and immunohistochemistry analysis.

RESULTS

The presence of both TNF alpha and TNF beta expression was demonstrated in most JRA and JSpA tissues, although samples from patients with pauciarticular JRA had somewhat lesser amounts of these cytokines. TNF beta expression correlated significantly with the occurrence of lymphocytic aggregates in tissues. Staining with monoclonal antibodies specific for the p55 and p75 receptors revealed that a diverse range of cell types expressed the receptors, with the most intense p55 staining on vascular endothelial cells. In the vast majority of synovial tissues, far greater numbers of cells expressed the p55 form of the receptor than the p75 form.

CONCLUSION

JRA and JSpA synovia are characterized by the presence of TNF alpha, TNF beta, and cells expressing TNFR. These findings provide further evidence that TNF, through autocrine/paracrine mechanisms, may amplify local inflammation, leading to joint destruction. The prominence of TNF beta in the synovium in particular subgroups of JRA patients and in JSpA patients may be a distinguishing feature of these diseases.