The chronic venous compartment syndrome

BACKGROUND

A chronic exertional compartment syndrome has only been observed in athletes and soldiers. In the vast majority, the disease affects the anterior compartment and the fibular muscle group, and only rarely the lateral and dorsal muscle compartments. Muscle tissue necrosis does not occur. In the course of venous diseases with a severe chronic venous stasis syndrome, a chronic venous compartment syndrome develops that differs considerably from the familiar functional syndrome. The predominant symptom is an uncurable cuff ulceration on the lower leg.

PATIENTS AND METHODS

From 1993 to 1996 a total of 16 patients with a chronic fascial compression syndrome underwent surgery on 18 extremities. The crural fascia was resected and a mesh graft was applied.

RESULTS

In the group of ten controls with healthy veins the average pressure in the deep compartment was 13.6 mmHg (range 9-17 mmHg) lying down and 29.9 mmHg (range 15-42 mmHg) standing up. In 14 patients with chronic fascial compression syndrome, the average pressure was higher, measuring 21.1 mmHg (range 8-47 mmHg) lying down and 62.5 mmHg (range 33-87) standing up. After surgery, the pressure dropped to 15.5 mmHg (range 5-24 mmHg) lying down and 34.5 mmHg (range 10-58 mmHg) standing up, but did not fall as low as the average values recorded in the control group or in the patient's healthy leg. The results from the standing up position were statistically significant (p = 0.003). Computed tomography showed major changes in the muscles indicating muscle atrophy and fatty degeneration. The crural fascia seemed to be incorporated in the scars of the subcutaneous tissue in large areas. After crural fasciectomy and healing of the ulceration, the tissue structure of the muscles recovered.

CONCLUSIONS

In chronic fascial compression syndrome, the trellis arrangement of the collagen fibres becomes disordered. This results in a loss of flexibility during muscle contraction. Every step causes an increase of intracompartmental pressure and microstructural injury. The consequence is resection of the crural fascia.

The effects of a prolonged running exercise on strength characteristics

The aim of this study was to examine concentric, isometric, and eccentric strength reductions in the quadriceps muscle following a prolonged running exercise. Before and after a 2 h run (28.4+/-1.4 km) peak torque (PT) of the knee extensors at angular velocities of -120, -90, -60, 0, 60, 120, 180, 240 degrees x s(-1) using an isokinetic dynamometer, electromyographic (EMG) activity of the vastus lateralis (VL) and vastus medialis (VM) muscles and height of a counter movement jump were recorded in twelve well-trained triathletes. Counter movement jump performances decreased by 10% and PT values were all significantly lower (p < 0.01) at each angular velocity following the run. The torque loss was significantly (p < 0.01) greater under eccentric contractions (from 18 to 21%) than under concentric ones (from 11 to 14%). EMG activity (RMS) was lower in both VL and VM muscles after the 2 h run but no difference existed in RMS losses between concentric and eccentric contractions. The present results demonstrate that 1) a prolonged running exercise more greatly affects eccentric force production in the quadriceps muscle, and 2) this specificity seems to be due to an impairment of the muscular contractile mechanism rather than a modification to the neural input.

Re-examination of training effects by electrostimulation in the human elbow musculoskeletal system

This study examines the effects of a 7 weeks sub-maximal training period of electrostimulation on the maximal isometric, concentric, eccentric voluntary torque and muscle contractile properties of the elbow flexor muscles of nine subjects. The daily program consisted of five series of six 6-s isometric actions (60 to 70% of maximal isometric voluntary action) at an elbow angle of 90 . After training the maximal voluntary isometric flexion torque increased significantly whereas the maximal voluntary isometric extension torque decreased significantly. Increases in isometric flexion torque were linked to an increase of the myoelectrical activity of the biceps brachii muscle. Under dynamic conditions flexion torque was significantly increased throughout the whole spectrum of angular velocities. These changes were accompanied by an increase in the myoelectrical activity of the agonist muscle under eccentric conditions and at two fast concentric angular velocities, without modifications of the myoelectrical activity of the antagonist muscle. The analysis of the electrical and mechanical twitches indicated that modifications of the muscle membrane electrical activity were also present at the muscle level. These results indicate that torque gains were attributed to neural adaptations and/or to a modification of the relative part of agonist and antagonist muscles in elbow flexion torque production.

A comparison of teaching strategies for integrating information technology into clinical nursing education

As health care becomes more information-intensive and diverse, there is a need to integrate information technology (IT) into clinical education. Little is known, however, about how to design instructional strategies for integrating information technology into clinical nursing education. This article outlines the instructional strategies used by faculty in five nursing programs who taught students to use a point-of-care information technology system. The article also reports students' computer acceptance and summarizes IT clinical teaching recommendations.

Assessment in multisite randomized clinical trials of patients with autistic disorder: the Autism RUPP Network. Research Units on Pediatric Psychopharmacology

Assessment of autistic disorder (autism) symptoms, primary and secondary, poses more challenging problems than ordinarily found in multisite randomized clinical trial (RCT) assessments. For example, subjects may be uncommunicative and extremely heterogeneous in problem presentation, and current pharmacological treatments are not likely to alter most core features of autism. The Autism Research Units on Pediatric Psychopharmacology (RUPP Autism Network) resolved some of these problems during the design of a risperidone RCT in children/adolescents. The inappropriateness of the usual anchors for a Clinical Global Impression of Severity (CGI-S) was resolved by defining uncomplicated autism without secondary symptoms as a CGI-S of 3, mildly ill. The communication problems, compromising use of the patient as an informant, were addressed by several strategies, including careful questioning of care providers, rating scales, laboratory tests, and physical exams. The broad subject heterogeneity requires outcome measures sensitive to individual change over a wide spectrum of treatment response and side effects. The problems of neuropsychologically testing nonverbal, lower functioning, sometimes noncompliant subjects requires careful instrument selection/adaptation and flexible administration techniques. The problems of assessing low-end IQs, neglected by most standardized test developers, was resolved by an algorithm of test hierarchy. Scarcity of other autism-adapted cognitive and neuropsychological tests and lack of standardization required development of a new, specially adapted battery. Reliability on the Autism Diagnostic Interview (currently the most valid diagnostic instrument) and other clinician instruments required extensive cross-site training (in-person, videotape, and teleconference sessions). Definition of a treatment responder required focus on individually relevant target symptoms, synthesis of possible modest improvements in many domains, and acceptance of attainable though imperfect goals. The assessment strategy developed is implemented in a RCT of risperidone (McDougle et al., 2000) for which the design and other methodological challenges are described elsewhere (Scahill et al., 2000). Some of these problems and solutions are partially shared with RCTs of other treatments and other disorders.

Effect of fruits, vegetables, or vitamin E--rich diet on vitamins E and C distribution in peripheral and brain tissues: implications for brain function

Age-related neurodegenerative conditions are the principal cause of declining cognitive and motor function during aging. Evidence support that fruits and vegetables containing generous amounts of antioxidant nutrients are important for neurological function. We investigated the effect of diets enriched with fruits or vegetables but low in vitamin E and a diet high in vitamin E on the distribution of vitamins C and E in the brain and dopamine release of Fischer 344 rat model, over an 8-month period. The low-vitamin E diet resulted in lowered alpha-tocopherol levels in brain and peripheral tissues, whereas the animals that received a diet enriched in vitamin E showed a significant increase, between 500-900%. Vitamin C concentration in plasma, heart, and liver was reduced in the vitamin E-supplemented group. It is concluded that supplementation or depletion of alpha-tocopherol for 8 months results in marked changes in vitamin E levels in brain tissue and peripheral tissues, and varied distribution of alpha-tocopherol throughout the different brain regions examined. In addition, compared to control group, rats supplemented with strawberry, spinach, or vitamin E showed a significant enhancement in striatal dopamine release. These findings suggest that other nutrients present in fruits and vegetables, in addition to the well-known antioxidants, may be important for brain function.

Role of erythropoietin in cortisol-induced hypertension

The mechanism of cortisol-induced hypertension remains unknown. We investigated a possible role of erythropoietin (EPO) as a mediator of hypertension in healthy male subjects treated with cortisol. In Study 1, blood pressure (BP) and serum EPO concentrations were measured on alternate days in nine subjects treated with 80 mg of cortisol per day for 5 days. In Study 2 the same parameters were measured in eight subjects randomised to cortisol (80 mg/day) or placebo and 10 subjects randomised to cortisol (200 mg/day) or placebo for 5 days. In Study 1, cortisol caused a significant increase in systolic BP (SBP) (115 +/- 2 vs 126 +/- 2 mm Hg, control vs day 5, P < 0.001) and serum EPO concentrations (14.5 +/- 2.7 vs 24.3 +/- 2.7 mU/mL, P < 0.001). In Study 2 both doses of cortisol increased SBP (118 +/- 2 vs 113 +/- 2 mm Hg, 80 mg cortisol vs placebo, P < 0.05 and 129 +/- 3 vs 113 +/- 2 mm Hg, 200 mg cortisol vs placebo, P < 0.001). Serum EPO concentrations were significantly increased at 200 mg cortisol (25.2 +/- 11.9 vs 15.9 +/- 3.5 mU/mL, P < 0.01) but not 80 mg cortisol (21.3 +/- 2.9 vs 14.9 +/- 3.1 mU/mL). In the 200 mg group there was a positive correlation between the change in SBP and the change in serum EPO concentration (r2 = 0.43, P < 0.05). These results point to a possible role for EPO as the mediator of cortisol-induced hypertension. Journal of Human Hypertension (2000) 14, 195-198.

Changes in baroreceptor sensitivity for heart rate during normotensive pregnancy and the puerperium

Normal pregnancy is associated with marked changes in cardiovascular haemodynamics, which in part may be due to changes in autonomic control mechanisms. Baroreflex sensitivity for heart rate (BRS) was calculated in the supine and standing positions using power spectral analysis of pulse interval (PI) and systolic blood pressure (SBP) in 16 normotensive pregnant women and 10 normotensive non-pregnant controls. The pregnant women were studied on three occasions during their pregnancy (early, mid- and late gestation) and once during the puerperium. Supine total SBP variability increased between early and late pregnancy by 79% [95% confidence intervals (CI) 30%, 145%; P<0. 001], and supine high-frequency PI variability decreased by 75% (CI 51%, 88%; P<0.001). Supine BRS fell by 50% (P<0.001), with values returning to early-pregnancy levels in the puerperium, which were similar to those recorded in the control group. Standing SBP variability and BRS values were unchanged during pregnancy and post partum. The low/high frequency ratio of PI variability, taken as a surrogate measure of sympathovagal balance, increased by 137% (CI 42%, 296%; P<0.01) in the supine but not the standing position from early to late pregnancy. This was due to a decrease in high-frequency variability rather than to an increase in low-frequency variability, suggesting that these changes may have been due to vagal withdrawal rather than increased sympathetic activity. Normotensive pregnancy is associated with a marked decrease in supine BRS, although the exact mechanisms for these changes remain unclear. Further studies are required to define whether changes in BRS and sympathovagal tone in early pregnancy can be used to predict the onset of pregnancy-induced hypertension.

Successful treatment of invasive nasal cryptococcosis in a ferret

Invasive cryptococcal rhinitis due to Cryptococcus neoformans var gattii was diagnosed in a castrated, 5-year-old, albino ferret with subcutaneous swelling of the nasal bridge. The diagnosis was based on histology, needle aspirate cytology and positive culture on Sabouraud's dextrose agar and birdseed agar. The ferret was successfully treated using a long course of itraconazole (25 to 33 mg orally once daily with food) subsequent to surgical debulking of the lesion, using sequential cryptococcal antigen titre determinations to guide therapy.

A minimized human integrin alpha(5)beta(1) that retains ligand recognition

Two isolated recombinant fragments from human integrin alpha(5)beta(1) encompassing the FG-GAP repeats III to VII of alpha(5) and the insertion-type domain from beta(1), respectively, are structurally well defined in solution, based on CD evidence. Divalent cation binding induces a conformational adaptation that is achieved by Ca(2+) or Mg(2+) (or Mn(2+)) with alpha(5) and only by Mg(2+) (or Mn(2+)) with beta(1). Mn(2+) bound to beta(1) is highly hydrated ( approximately 3 water molecules), based on water NMR relaxation, in agreement with a metal ion-dependent adhesion site-type metal coordination. Each fragment saturated with Mg(2+) (or Mn(2+)) binds a recombinant fibronectin ligand in an RGD-dependent manner. A conformational rearrangement is induced on the fibronectin ligand upon binding to the alpha(5), but not to the beta(1) fragment, based on CD. Ligand binding results in metal ion displacement from beta(1). Both alpha(5) and beta(1) fragments form a stable heterodimer (alpha(5)beta(1) mini-integrin) that retains ligand recognition to form a 1:1:1 ternary complex, in the presence of Mg(2+), and induces a specific conformational adaptation of the fibronectin ligand. A two-site model for RGD binding to both alpha and beta integrin components is inferred from our data using low molecular weight RGD mimetics.

Ontogeny of orientation flight in the honeybee revealed by harmonic radar

Cognitive ethology focuses on the study of animals under natural conditions to reveal ecologically adapted modes of learning. But biologists can more easily study what an animal learns than how it learns. For example, honeybees take repeated 'orientation' flights before becoming foragers at about three weeks of age. These flights are a prerequisite for successful homing. Little is known about these flights because orienting bees rapidly fly out of the range of human observation. Using harmonic radar, we show for the first time a striking ontogeny to honeybee orientation flights. With increased experience, bees hold trip duration constant but fly faster, so later trips cover a larger area than earlier trips. In addition, each flight is typically restricted to a narrow sector around the hive. Orientation flights provide honeybees with repeated opportunities to view the hive and landscape features from different viewpoints, suggesting that bees learn the local landscape in a progressive fashion. We also show that these changes in orientation flight are related to the number of previous flights taken instead of chronological age, suggesting a learning process adapted to changes in weather conditions, flower availability and the needs of bee colonies.

Head and neck tumors: fractionated frameless stereotactic interstitial brachytherapy-initial experience

The authors used a frameless stereotactic navigation system, the Vogele-Bale-Hohner head holder, and a targeting device to reproducibly position brachytherapy needles for fractionated interstitial brachytherapy in 12 patients with inoperable cancers of the head and neck. In all cases, deviations of the needle relative to the planned position were within 1-15 mm depending on the location of the tumor.

Overexpression of BCL-2, BCL-X, and BAX in primary central nervous system lymphomas that occur in immunosuppressed patients

In contrast to primary central nervous system lymphomas (PCNSLs) that occur in immunocompetent patients, most of those that occur in immunosuppressed patients are associated with Epstein-Barr virus (EBV). BCL-2-related proteins either block or promote cell death, forming homo- or heterodimers with each other. LMP-1, EBV latent protein, has been shown to upregulate BCL-2 and BCL-XL. This observation suggests that these proteins may be involved in the transformation process of EBV-infected cells. Twenty-three cases of PCNSLs were studied: 12 of the patients were immunosuppressed, and 11 were immunocompetent. For all cases, we collected clinical information, histologic data, and immunophenotype and tested for the presence of EBV (EBER-1, LMP-1). Apoptosis was assessed by the TdT-mediated dUTP-biotin nick-end labeling method and quantified by image analysis. In three cases, electron microscopy was performed. The BCL-2 family proteins (BCL-2, BCL-X, MCL1, and BAX) and p53 expression were studied by immunohistochemistry on paraffin slides. All cases were classified as diffuse large B-cell lymphomas. PCNSLs in immunosuppressed patients were characterized by EBV association, necrosis, important gliosis, and numerous macrophages. There was no significant difference between the two groups regarding the TdT-mediated dUTP-biotin nick-end labeling staining (P = .08). In contrast, PCNSLs in immunosuppressed patients were shown to express high levels of BCL-2, BCL-X, and BAX in more than 80% of tumor cells in 7, 10, and 11 cases, respectively. In immunocompetent patients, only one case showed a high level of BCL-2 expression in more than 80% of the cells, whereas BCL-X and BAX were overexpressed in two cases. These differences are significant (P < .05). In contrast, there was no significant difference between the two groups in MCL-1 expression. Besides EBV association and necrosis, PCNSLs related to immunosuppression are characterized by an overexpression of BCL-2-related proteins, without dramatically modifying their susceptibility for apoptosis.

Complementary neural mechanisms for tracking items in human working memory

Recognition of a specific visual target among equally familiar distracters requires neural mechanisms for tracking items in working memory. Event-related functional magnetic resonance imaging revealed evidence for two such mechanisms: (i) Enhanced neural responses, primarily in the frontal cortex, were associated with the target and were maintained across repetitions of the target. (ii) Reduced responses, primarily in the extrastriate visual cortex, were associated with stimulus repetition, regardless of whether the stimulus was a target or a distracter. These complementary neural mechanisms track the status of familiar items in working memory, allowing for the efficient recognition of a currently relevant object and rejection of irrelevant distracters.

Pharmacotherapy of early-onset depression. Update and new directions

Although an increased recognition of depressive disorders in youth represents a positive conceptual change over the past decades, there still is a very limited amount of research on useful treatment interventions. The paucity of data is particularly keen for the use of psychotropic drugs. For example, by applying the criteria suggested by the International Psychopharmacology Algorithm Project, there barely are enough first-grade ("Level A," meaning at least two RCTs) data supporting the short-term efficacy of antidepressants (the SSRIs) in the treatment of juvenile depression. And yet, limited data have not translated into limited use in routine clinical practice. In fact, the use of antidepressant medications has increased exponentially over the last decade, a change that is especially conspicuous for individuals less than 18 years of age. The perceived safety of the SSRIs and other novel antidepressants is partly at the root of their increased popularity. Data regarding their safety are likewise quite limited, however, and essentially are nonexistent for longer-term use. Based on the reviewed data, a medication algorithm for the treatment of early-onset depression can be suggested (Fig. 1). The algorithm underscores the need for adequate evaluation and diagnostic assessment, with particular attention to comorbid conditions (such as a bipolar diathesis) that may dictate alternative treatment strategies. In general, psychotherapy is the initial approach to juvenile MDD, with medication use reserved for more severe cases or those not responding to psychotherapy alone. Given that only two types of psychotherapy and two SSRIs have adequate controlled short-term efficacy data, all but the initial steps must be undertaken guided by clinical judgment and an individualized risk-benefit analysis. An algorithm such as this one, based on the very limited efficacy and safety data available, may be viewed as setting priorities for a comprehensive research agenda, more than dictating rigid treatment guidelines. In closing, it can be suggested that future research on the pharmacotherapy of early-onset depressive disorder pay particular attention to the following three aspects: 1. Too many drugs, too few data: Rapid advances in drug development have led to a plethora of available antidepressant agents. It is clear that there are many more agents available than can be adequately studied at present. Because many such agents are mechanistically similar, if not identical, it may be wise to focus research efforts on truly novel agents, particularly those (such as the CRH receptor antagonists, or those affecting neurosteroidogenesis) whose action is based on preclinical and clinical pathophysiologic disease paradigms. 2. Longitudinal follow-up and maintenance studies: Essentially all reviewed treatment studies have been short-term trials. There is a marked paucity of longer-term follow-up data, or of naturalistic and "real-world" effectiveness studies. For example, one of the few studies addressing maintenance pharmacotherapy for early-onset depression has demonstrated surprisingly high recurrence rates, even for those subjects actively on maintenance medication. 3. Long-term safety: Clinicians and parents alike often face difficult decisions regarding the long-term exposure of antidepressant drugs on the developing brain. Although no definitive long-term safety data are likely to become available anytime soon, real risks, such as suicide, and potential sequelae of long-term exposure to the underlying illness itself need all to be part of any decision-making process. Preclinical studies have shown that brain-derived neurotrophic factor (BDNF) levels can be upregulated by antidepressants, and low BDNF factors have been associated with atrophic brain changes in recurrent forms of adult MDD. Although these observations require specific application to juvenile forms of the disorder, they raise the exciting prospect that the natural course of the illne

Antiproteinuric effect of calcium antagonists on puromycin-induced experimental nephrosis

Calcium antagonists have a potential for beneficial effects on kidney function unrelated to their antihypertensive action. In this study we have investigated the efficacy of calcium antagonists compounds (verapamil, nifedipine and diltiazem) on reversible acute renal insufficiency, proteinuria and interstitial nephritis induced by the puromycin ammonucleoside (PAN). An increase in blood pressure (BP) was detected on day 14, with no statistical differences in the response to calcium antagonists. Serum creatinine concentration increased to 1.2 mg/dL on day 7 after PAN and decreased to 0.7 mg/dL at 14 days, calcium antagonists shortened the time required to reach baseline or control levels. Calcium antagonists also reduced proteinuria in the PAN-treated animals, in both day 7 and day 14. Differential effects of the antagonists were observed. Verapamil caused a greater reduction (p < 0.01) in proteinuria than nifedipine or diltiazem in day 7. Moreover, verapamil (p < 0.01) and nifedipine (p < 0.01) reduced the total number of interstitial infiltrating leukocytes from 690 to 120 and 425 positive cells/20 high power fields (x63) respectively, by contrast, diltiazem had no effect. We conclude that in this model of PAN nephropathy verapamil is more effective in reducing both proteinuria and the severity of acute interstitial nephritis than either nifedipine or diltiazem. The possible clinical implications of these results remain to be elucidated.

The position of phosphorylcholine on the lipopolysaccharide of Haemophilus influenzae affects binding and sensitivity to C-reactive protein-mediated killing

The lic1 locus of Haemophilus influenzae controls the incorporation of environmental choline into lipopolysaccharide (LPS) as phosphorylcholine (ChoP) as well as the phase variation of this structure. ChoP is the target of an acute phase reactant in serum, C-reactive protein (CRP), which mediates killing through the activation of complement when bound to the organism. Structural analysis of the oligosaccharide region of the H. influenzae LPS showed that ChoP is linked to different hexose residues on different chain extensions in strains Rd and Eagan. Differences in the molecular environment of ChoP affect the epitope defined by monoclonal antibody 12D9 and were associated with polymorphisms within LicD, a putative diphosphonucleoside choline transferase. Exchanging the licD genes between the two strains with ChoP on different chain extensions was sufficient to switch its position. Allelic variants with ChoP on a hexose on heptose III rather than heptose I were sensitive to CRP-mediated serum bactericidal activity regardless of the genetic background. Differences in CRP-mediated killing correlated with differences in the binding of CRP from human serum to whole bacteria. This suggests that, in addition to the mechanism involving phase variation, the structural rearrangements within the oligosaccharide contribute to evasion of innate and acquired immunity.

A knowledge-based patient assessment system: conceptual and technical design

This paper describes the design of an inpatient patient assessment application that captures nursing assessment data using a wireless laptop computer. The primary aim of this system is to capture structured information for facilitating decision support and quality monitoring. The system also aims to improve efficiency of recording patient assessments, reduce costs, and improve discharge planning and early identification of patient learning needs. Object-oriented methods were used to elicit functional requirements and to model the proposed system. A tools-based development approach is being used to facilitate rapid development and easy modification of assessment items and rules for decision support. Criteria for evaluation include perceived utility by clinician users, validity of decision support rules, time spent recording assessments, and perceived utility of aggregate reports for quality monitoring.

Critical evaluation of ECV304 as a human endothelial cell model defined by genetic analysis and functional responses: a comparison with the human bladder cancer derived epithelial cell line T24/83

Early reports indicated that ECV304 was a spontaneously-transformed line derived from a Japanese human umbilical vein endothelial cells (HUVEC) culture. Many morphological, immunochemical, and genetic studies provided further evidence that ECV304 was a valuable biomedical research tool and could be used to study processes that include angiogenesis in vitro and signal transduction by a variety of G protein-coupled receptors. However, several distinct differences between ECV304 and HUVEC are now apparent and recent reports have indicated genetic similarity between ECV304 and T24/83, a human bladder cancer cell line. To further assess the utility of ECV304 as a human endothelial cell model, we compared the functional responses of ECV304 and T24/83 to a range of G protein-coupled receptor agonists. We also used DNA fingerprinting to karyotype both ECV304 and T24/83. Both ATP and uridine triphosphate (UTP) stimulated inositol phosphate metabolism in ECV304 without alteration of cAMP levels. Comparative data using selective P2Y receptor agonists indicated that this response, leading to calcium mobilization from intracellular stores, was predominantly mediated by the activation of P2Y2 receptors. Similar responses were recorded from both ECV304 and T24/83 cells. ECV304 expressed a relatively high basal activity of NOS that was reduced by L-NAME and stimulated by P2Y2 receptor agonists. In contrast, P2Y2 receptor activation did not induce prostaglandin synthesis in ECV304. Both ECV304 and T24/83 express receptors for adenosine, adrenaline, and calcitonin, which stimulate adenylate cyclase. Proliferation of ECV304 and T24/83 cells, measured by the incorporation of [3H]thymidine into DNA, was largely serum-independent. This was in contrast to parallel experiments with porcine and bovine aortic endothelial cells that indicated a marked serum-dependent increase in DNA synthesis. Genetic analysis confirmed that ECV304 and T24/83 are identical. ECV304 displays some endothelial characteristics and is useful for the study of receptor pharmacology. However, ECV304 is not of HUVEC origin and is therefore an inappropriate cell line to study endothelial cell biology.

Research Units on Pediatric Psychopharmacology (RUPP) Autism Network. Background and rationale for an initial controlled study of risperidone

This article has reviewed the background and rationale for the choice of risperidone as the first drug to be studied by the RUPP Autism Network. Risperidone has potent effects on 5-HT and DA neuronal systems, both of which have been implicated in the pathophysiology of autism. Unlike the typical antipsychotics, haloperidol and pimozide, which have been shown to be effective for reducing many of the maladaptive behaviors associated with autism, risperidone's 5-HT2A/DA D2 ratio of receptor blockade appears to produce a lower risk of acute and chronic extrapyramidal side effects, as well as enhanced efficacy for the "negative" symptoms of autism. Indirect clinical and preclinical evidence supports the use of risperidone to treat impaired social behavior, interfering repetitive phenomena, and aggression, targets of pharmacotherapy for many patients with autism. Numerous published open-label trials in children and adolescents with autism and related PDDs and one double-blind, placebo-controlled study in adults suggest that risperidone has promise for the treatment of children and adolescents with autism. Because most of these studies have been short-term, open-label trials in small samples, however, a large-scale controlled study of risperidone in children and adolescents with autism is needed to confirm these results. Finally, because it is likely that children who demonstrate short-term benefit from risperidone will remain on the medication indefinitely, the longer-term effectiveness and safety of risperidone in this population also needs to be determined. The design of this study and the assessments used are described separately.

T-cell receptors and autoimmune thyroid disease--signposts for T-cell-antigen driven diseases

The human autoimmune thyroid diseases (AITDs) are characterized by profuse infiltrates of both CD4+ and CD8+ T cells. The intrathyroidal T-cell-receptor repertoire in Graves' disease, more than in Hashimoto's disease, has been shown to be biased as evidenced by phenotypic analysis and by the use of a restricted T-cell-receptor variable (V) gene repertoire seen in both TCR alpha and beta chains. Evidence for a bias in the T-cell repertoire has also been observed in animal models of induced and spontaneous autoimmune thyroiditis. We found a similar phenomenon of autoimmune thyroid-related T-cell bias in thyroid-humanized scid mice. In these studies we transplanted lymphocyte-depleted thyrocytes and autologous peripheral lymphocytes from AITD patients with a basement membrane preparation which allowed the formation of an artificial thyroid which we have called an "organoid". T-cell clonal expansion was present in these artificial mixed-cell organoids which appeared to mimic the in vivo process. Such clonal expansion was suggestive of an antigen-driven immune response and could also be identified in thyroid tissue from patients with Graves' disease. Our data on scid mice grafted with human mixed-cell thyroid organoids, therefore, suggested that the major antigens driving T-cell selection in patients with AITD were most likely to be thyroid specific. These antigens include thyroglobulin, thyroid peroxidase, and the receptor for thyroid stimulating hormone (TSHR) on the surface of thyroid epithelial cells and we found significant T-cell proliferation to synthetic TSHR peptides in patients with AITD as compared with normals. Our search for a TCR recognition motif for the autoantigen TPO did not reveal any specific sequence motifs. Instead, analysis of the physico-chemical characteristics i.e. hydrophobicity of the amino acids in the CDR3 (N) region of the TCR alpha chain, revealed a strong negative linear correlation between strength of stimulation and the average hydrophobicity of N-region amino acids. This led us to hypothesize that lower affinity T-cell clones were commonly more hydrophobic in their CDR3 alpha region amino acids in keeping with potential crossreactivity of such T cells as a consequence of promiscuous, hydrophobic CDR3 regions. This phenomenon would be analogous to polyreactive, natural autoantibodies which tend to be crossreactive and 'sticky'. Thus, the physico-chemical characteristics of the TCR alpha CDR3 region supported the interaction with antigen/MHC by potentially cross-reactive T cells of low affinity. It would seem likely that such low-affinity autoreactive T-cell populations serve as a pool of potentially pathogenetic cells. These cells would be able to respond to an insult which, via a number of possible mechanisms such as molecular mimicry, would initiate a thyroid lymphocytic infiltration in an antigen-driven fashion with intrathyroidal T-cell expansion and a marked bias in the utilization of T-cell-receptor V genes.