Is electrogastrography a substitute for manometric studies in children with functional gastrointestinal disorders?

We performed simultaneous fasting and fed antroduodenal manometry and EGG in 25 children with functional bowel disorders. Three patients (12%) had an uninterpretable EGG. The manometric studies showed severe neuropathy in six patients; milder neuropathic changes in five patients; postprandial hypomotility in one patient; myopathy in four patients, and normal motility in the remaining six patients. The percentage of tachygastria time (frequency > 3.5 cycles/min) was higher in the patiens with mild (44.1 +/- 15.8%) and severe (48 +/- 19.1%) neuropathy than in the patients with myopathy (20 +/- 16.2%, P < 0.05) or with normal motility (23 +/- 13.3%, P < 0.05). There was a considerable overlap in the percentage of tachygastria and total arrhythmia time among the different study groups. The ratio of post- to preprandial power was significantly higher (2.5 +/- 0.07) in children with normal motility than in the other patients groups. Every child with total arrhythmia time < 35% and a ratio of post- to preprandial power > 2.4 had normal manometry. In summary, EGG differentiated groups of children with normal manometry from others with neuropathic or myopathic changes, but in a minority of patients the study was not interpretable and there was overlap in EGG results between children with normal and abnormal manometry.     

A 76-amino acid disulfide loop in the Yersinia pseudotuberculosis invasin protein is required for integrin receptor recognition

The Yersinia pseudotuberculosis invasin protein is a 986-amino acid protein that promotes bacterial penetration into mammalian cells by avidly binding multiple beta 1-chain integrins. A 192-amino acid carboxyl-terminal domain of invasin was previously shown to be sufficient for binding. Evidence is presented here that a 76-amino acid disulfide loop in the integrin binding domain of invasin is required for invasin-mediated cell binding and entry. Bacterial mutants that were altered at either of 2 cysteine residues in the binding domain of invasin were completely defective for entry. Purified invasin protein derivatives altered at either of these cysteines, in contrast to the wild-type invasin, did not promote either cell binding or penetration. Analysis of proteolytic products of invasin in the presence or absence of reducing agent provided evidence of an intra-chain disulfide bond near the carboxyl terminus of the protein. Alkylation of invasin derivatives with [3H]iodoacetate indicated that these 2 cysteines were normally disulfide-bonded. A treatment that resulted in the maximal reduction of the disulfide bond also resulted in maximal loss of cell attachment activity. These results indicate that the 76-amino acid disulfide loop at the carboxyl terminus of invasin is required for recognition by integrins.     

Fibronectin fragments modulate human retinal capillary cell proliferation and migration

Capillary morphogenesis involves cell-cell and cell-matrix interactions. Proteases elaborated by capillary cells modify the extracellular matrix (ECM) to facilitate capillary tube formation. Previously, we detected the presence of fibronectin fragments (Fn-f) associated with the proform of matrix metalloprotease-2 (MMP-2) in conditioned medium of human retinal endothelial cells (HRECs). Association of this fragment to latent MMP-2 prevented autocatalytic activation of MMP-2, suggesting a modulatory role of Fn-f in MMP-2 activation. In this report, we examined the potential role of Fn-f on two processes involved in angiogenesis, proliferation and migration of vascular cells. The effects of Fn-f on proliferation were determined by DNA synthesis and cell counts. Their effects on migration were assessed using modified Boyden chambers. Seven Fn-f were tested on vascular cell migration and/or proliferation. Three Fn-f induced migration. Fn-f of 30-kDa and 120-kDa size positively affected proliferation of microvascular cells but not macrovascular cells. A 45-kDa gelatin binding fragment of Fn inhibited HREC proliferation but stimulated pericyte and smooth muscle cell proliferation. The potency of these fragments exceeded that of the known angiogenic growth factor, basic fibroblast growth factor (bFGF), on HREC migration. ECM components such as fibronectin may influence capillary morphogenesis by the generation of fragments that can modulate proliferation, migration, and protease activation. In the setting of diabetes, excess Fn is generated and is available for degradation. Thus, the production of Fn-f may be specifically relevant to the angiogenesis observed in proliferative diabetic retinopathy.     

Remote control of a robot in a map network

The automated control of manufacturing devices on a common communications network is a necessity for the factory of the future. The manufacturing automation protocol (MAP) represents a major effort by a group of companies towards meeting this need, and apparently is becoming a standard for factory-floor communications. In this project, an ASEA 2000 robot was used with a computer-controlled ply-cutting machine in a simulated factory sheet-metal cell to demonstrate coordinated inter- and intra-cell communications. Both machines used a MAP network to send and receive information from the cell-controller computer, and to coordinate cell operation. The methodology, hardware and software required to adapt the ASEA robot to the MAP network are described. This methodology will be useful in adapting other computer-controlled manufacturing devices to MAP networks.     

Specific recognition of HLA-E, but not classical, HLA class I molecules by soluble CD94/NKG2A and NK cells

The CD94/NKG2 receptors expressed by subpopulations of NK cells and T cells have been implicated as receptors for a broad range of both classical and nonclassical HLA class I molecules. To examine the ligand specificity of CD94/NKG2 proteins, a soluble heterodimeric form of the receptor was produced and used in direct binding studies with cells expressing defined HLA class I/peptide complexes. We confirm that CD94/NKG2A specifically interacts with HLA-E and demonstrate that this interaction is dependent on the association of HLA-E with peptide. Moreover, no interaction between CD94/NKG2A and classical HLA class I molecules was observed, as assayed by direct binding of the soluble receptor or by functional assays using CD94/NKG2A+ NK cells. The role of the peptide associated with HLA-E in the interaction between HLA-E and CD94/NKG2A was also assessed. All class I leader sequence peptides tested bound to HLA-E and were recognized by CD94/NKG2A. However, amino acid variations in class I leader sequences affected the stability of HLA-E. Additionally, not all HLA-E/peptide complexes examined were recognized by CD94/NKG2A. Thus CD94/NKG2A recognition of HLA-E is controlled by peptide at two levels; first, peptide must stabilize HLA-E and promote cell surface expression, and second, the HLA-E/peptide complex must form the ligand for CD94/NKG2A.     

Fluoxetine tenth anniversary update: the progress continues

This tenth anniversary review/update of fluoxetine concentrates on the past 5 years of its clinical application. The mechanism of action of fluoxetine; its metabolism; its efficacy in patients with various diagnostic subgroups of depression, patients with coincident medical disease, children and adolescents with depression, patients with eating disorders, and patients with obsessive-compulsive disorder (OCD); its long-term (maintenance) efficacy; its side effects and toxicity; and pharmacoeconomic considerations are reviewed. Pharmacotherapy is currently the only proven method for treating major depressive disorder that is applicable to all levels of severity of major depressive illness. Since its introduction 10 years ago, fluoxetine has been available to psychiatrists, primary care physicians, and other nonpsychiatric physicians as full-dose effective pharmacotherapy for patients with depression. Fluoxetine has been widely prescribed by physicians knowledgeable in pharmacology and in the treatment of depression because of its proven efficacy (ie, equal to that of tricyclic antidepressants [TCAs]), its ease of administration (with full therapeutic dosing usually starting from day 1), its generally benign side-effect profile, its remarkable safety in over-dose, and its proven effectiveness in the most common depressed patient population--anxious, agitated, depressed patients--as well as in patients with various subtypes and severities of depression. In more recent years it has also proved effective in the treatment of bulimia, an entity for which only limited or inadequate treatment options had been previously available. In OCD, fluoxetine, with its more acceptable side-effect profile and greater ease of dosing, presents a favorable alternative to previous drug therapy and is useful in treating both obsessions and compulsions. Fluoxetine is currently recognized among clinicians as efficacious in treating anxiety disorders and is being used successfully in special depressed populations such as patients with medical comorbidity, elderly patients, adolescents, and children. Rapid discontinuation or missed doses of short-half-life selective serotonin reuptake inhibitors, TCAs, and heterocyclic antidepressants are associated with withdrawal symptoms of a somatic and psychological nature, which cannot only be disruptive, but can also be suggestive of relapse or recurrence of depression. In striking contrast to these short-half-life antidepressants, fluoxetine is rarely associated with such sequelae on sudden discontinuation or missed doses. This preventive effect against withdrawal symptoms on discontinuation of fluoxetine is attributed to the unique extended half-life of this antidepressant. Current studies show that the overall increased effectiveness of fluoxetine in treating depression compensates for its higher cost, compared with older drugs, by reducing the need for physician contact because of increased compliance and less need of titration, and by reducing premature patient discontinuation, thereby yielding fewer relapses, less recurrence, and less reutilization of mental health services.