bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel visual immunoassay for coeliac disease screening
Authors: Garrote  , Sorell  , Alfonso  , Acevedo  , Ortigosa  , Ribes‐Koninckx  , Gavilondo  , Méndez  
Published: March 2003

BackgroundTo date, the most commonly accepted techniques for the screening of coeliac disease are indirect immunofluorescence and enzyme‐linked immunosorbent assay (ELISA), which reveal antiendomysium and antigliadin antibodies respectively. We report the use of a simple visual system for coeliac disease screening based on the use of Staphylococcus aureus protein A, which binds to both IgG and IgA, thus avoiding the need for two parallel immunoassays.Materials and methodsOpaque polystyrene microwell strips coated with a wheat gliadin extract were incubated with sera followed by incubation with protein A–colloidal gold conjugate. The resulting colour was compared with that of positive and negative control sera. The procedure took less than an hour.ResultsOne hundred and forty‐five biopsy‐proven sera, 94 from active coeliac patients and 51 from non‐coeliac patients with diverse gastrointestinal pathologies or diabetes mellitus, were assayed. Ninety of the 94 sera from the active coeliac patients were positive, whereas only 3 of the 51 non‐coeliac control subjects were positive. The technique has a sensitivity of 95.7% and a specificity of 94.1%.ConclusionsThe sensitivity and specificity of the visual system are greater than those of most ELISA systems and are similar to those observed with IgA antiendomysium antibodies when tested in the same population. Moreover, it is inexpensive, quick, simple to perform and easy to interpret, i.e. it requires no qualified personnel. It is for these features, together with the outstanding sensitivity and specificity, that we propose this immunoassay as a new test for reliable coeliac disease screening.
Amino acid concentration in the interstitium of human skeletal muscle: a microdialysis study
Authors: Gutierrez  , Anderstam  , Alvestrand  
Published: March 2003

BackgroundThe microdialysis technique has been widely used for in vivo monitoring of the interstitial composition of several tissues. Remarkably high concentrations of taurine and glycerol were reported in a recent human study. As taurine and glycerol are predominantly present in the intracellular space, cellular trauma after probe insertion may have resulted in elevated interstitial concentrations. With the present study we wanted to investigate the impact of the initial trauma on the interstitial concentrations of amino acids and glycerol.MethodsMicrodialysis probes were inserted into the vastus lateralis muscle in eight subjects. Using a slow perfusion rate of 0.3 μL min−1, dialysate samples were collected in five 75‐min periods. Simultaneously, plasma samples were taken from a peripheral vein for amino acid determination.ResultsDuring the first collection period, the dialysate concentration for 21 measured amino acids was on average 180% ± 51% higher than the concentration in plasma water. This difference decreased to 52% ± 15%, 32% ± 8%, 37% ± 8% and 31% ± 7% during periods 2, 3, 4 and 5 respectively. Carnosine, which is not present in plasma, was detected in high concentrations in the interstitium during the first collection period and decreased subsequently.ConclusionIn the post‐absorptive phase, the concentrations of most amino acids in muscle interstitium are slightly higher than in venous plasma water. The leakage of intracellular amino acids, because of probe insertion, will initially lead to an overestimation of the actual interstitial concentration of amino acids. Therefore, reliable baseline values of amino acids cannot be obtained until 120–150 min after probe insertion. The dialysate concentration of carnosine may be used as a marker of cellular leakage.
Hydroxyurea interferes with antigen‐dependent T‐cell activation in vitro
Authors: Orendi  , Nottet  , De Vos  , Visser  , Snippe  , Boucher  , Verhoef  
Published: March 2003

BackgroundHydroxyurea is believed to inhibit human immunodeficiency virus type 1 (HIV‐1) in HIV disease by decreasing the amount of intracellular deoxynucleotides needed for viral replication. A plasma concentration of 400 μmol L−1 is tolerated in oncological diseases. The present study focused on the possible interference of hydroxyurea with antigen‐dependent T‐cell activation as an alternative explanation for inhibiting HIV replication in vivo.MethodsThe effect of hydroxyurea on common antigen‐induced cell proliferation was studied in peripheral blood mononuclear cells (PBMC) in vitro.ResultsHydroxyurea inhibited Candida albicans‐induced cell proliferation at a low concentration (1 μmol L−1), while at least 10 μmol L−1 was required to block HIV‐1 replication in phytohaemagglutinin (PHA)‐stimulated PBMC.ConclusionHydroxyurea inhibits antigen‐induced lymphoproliferation in vitro at a concentration at which it does not inhibit PHA‐induced HIV replication. Hydroxyurea may inhibit HIV‐1 in CD4+ T cells in vivo not only by decreasing the amount of intracellular deoxynucleotides, but more specifically by interfering with antigen‐dependent T‐cell activation, thereby causing a reduction in the number of HIV target cells.
Distal procto‐colitis and n‐3 polyunsaturated fatty acids: the mechanism(s) of natural cytotoxicity inhibition
Authors: Almallah  , El‐Tahir  , Heys  , Richardson  , Eremin  
Published: March 2003

BackgroundAltered natural killer (NK) and lymphokine‐activated killer (LAK) cell activities have been reported with ulcerative colitis (UC). Previously, we have shown that in patients with UC, the n‐3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), specifically inhibit natural cytotoxicity with clinical improvement in disease activity. The aim of this study therefore was to evaluate the possible mechanism(s) involved in this inhibition, and in particular the alteration of production of interleukin 2 (IL2) and the arachidonic acid metabolite leukotriene B4 (LTB4), both known to modulate NK cell activity.Materials and methodsEach patient with procto‐colitis received either fish oil extract (EPA 3.2 g, DHA 2.4 g; n = 9) or placebo (n = 9) daily for 6 months. Monthly assessment included disease activity using clinical and sigmoidoscopic scores. Peripheral blood mononuclear (PBMN) cells were isolated and NK cell cytotoxic activity in vitro was measured. Monthly serum samples were analysed for LTB4, IL2 and soluble IL2 receptors (sIL2R).ResultsThe n‐3 PUFAs group had significantly reduced NK cell activity, compared with the placebo group (P < 0.05, Mann–Whitney U‐test). In the n‐3 PUFA group, incubation of PBMN cells for 72 h with recombinant interleukin 2 (rIL2) reversed the NK inhibition. In patients with active proctocolitis, serum levels of LTB4 correlated positively with NK cell cytotoxicity (r = 0.873, P < 0.05, Kendall's correlation coefficient). After six months of n‐3 PUFAs supplementation, serum levels of LTB4 were undetectable with concurrent significant reduction in NK cell cytotoxic activity. The latter was associated with significant reduction of serum IL2 and sIL2R levels (P < 0.05).ConclusionThis study has demonstrated both evidence of suppression of immune reactivity and concurrent reduction in disease activity in patients with proctocolitis receiving n‐3 PUFAs supplementation. This may have important implications for therapy in patients with UC.
Insulin resistance, lipid and fatty acid concentrations in 867 healthy Europeans
Authors: Baldeweg  , Golay  , Natali  , Balkau  , Del Prato  , Coppack  
Published: March 2003

BackgroundInsulin resistance, dyslipidaemia and abnormal nonesterified fatty acid (NEFA) metabolism are features of the ‘metabolic syndrome’, but the mechanisms of these relationships are uncertain.Materials and methodsWe studied associations between insulin resistance and lipoprotein concentrations by retrospective analysis of euglycaemic hyperinsulinaemic clamp data from 867 normoglycaemic subjects in 21 European centres. Data on NEFA concentrations were available in a subgroup of 541 subjects from 9 clinical centres. These subjects' characteristics do not vary significantly from those of the whole cohort.ResultsAfter adjustment for the effects of age, sex, obesity and intercentre variability, regression analysis showed relationships between triglycerides and markers of insulin sensitivity. There were significant correlations between triglycerides and fasting plasma glucose (P < 0.0001), fasting plasma insulin (P < 0.0001) and mean glucose infusion rate at steady state (M‐value, P < 0.0001). Indices of insulin resistance were related to NEFA concentrations. Fasting NEFA were negatively correlated with the M‐value (P < 0.0001). Non‐esterified fatty acids at steady state were positively correlated with fasting markers of insulin resistance: fasting plasma glucose (P < 0.05), fasting plasma insulin (P < 0.005) and negatively correlated with the M‐value (P < 0.0005). There were relationships between fasting concentrations of plasma lipids and of NEFAs. Non‐esterified fatty acids at steady state correlated with fasting triglycerides (P < 0.0001), but not with any of the other plasma lipoprotein concentrations. The associations of fasting triglycerides with the M‐value and with NEFAs at steady state were independent of each other. All these associations were independent of obesity and geographical locationConclusionThe results in this large cohort of healthy European subjects suggest that triglyceride concentrations depend upon both insulin's gluco‐regulation (estimated by glucose uptake) and antilipolytic insulin action (measured by NEFA levels) during an euglycaemic clamp.
Effects of percutaneous transluminal coronary angioplasty on coronary adenosine concentrations in humans
Authors: Paganelli  , Saadjian  , Sampol  , Maixent  , Levy  , Guieu  
Published: March 2003

BackgroundEven minimal amounts of adenosine is released during myocardial ischemia. Its role in coronary blood flow has been extensively studied, but little is known about its behaviour during percutaneous transluminal angioplasty (PTCA) in man.Material and methodsUsing in situ samples the aim of this study was to evaluate adenosine plasma concentration before and after PTCA. Ten patients (8 men and 2 women, mean age 65 ± 9 years) with a single stenosis of the left anterior descending coronary artery (LAD) of at least 70% and 10 healthy volunteers (4 men and 6 women, mean age 55 ± 9 years) were included in the study.Results and discussionWe found that there is a close relationship between the degree of the stenosis and the adenosine concentrations in the great cardiac vein and in the LAD, and that after PTCA there is a drop in adenosine concentration downstream from the stenosis. This study confirms the crucial role of adenosine in coronary blood flow control.
Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia
Authors: Fiorini  , Littarru  , Coppa  , Kantar  
Published: March 2003

BackgroundPolymorphonuclear leucocytes (PMN) from subjects with primary ciliary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN from children with PCD.DesignMembrane polarity was studied in 11 children with PCD and in healthy controls by measuring the steady‐state fluorescence excitation and emission spectra of 2‐dimethylamino[6‐lauroyl]naphthalene (Laurdan), which is known to be incorporated at the hydrophobic–hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surroundings. Laurdan shows a marked steady‐state emission red shift in polar solvents, with respect to nonpolar solvents. Moreover, the effect of the microtubule disassembling agent colchicine on PMN membrane polarity was evaluated.ResultOur results show a red shift of the fluorescence excitation and emission spectra of Laurdan in PMN from the PCD group with respect to the control group. These data indicate an increase in membrane polarity of PMN from the PCD group. Treatment of PMN with colchicine induced a red shift in the Laurdan excitation and emission spectra with the same trend observed in PMN from the PCD group.ConclusionPMN from children with PCD are characterized by an increased plasma membrane polarity. These changes could be the basis of the modifications in the locomotory activities of PMN. The observed alterations may be attributed to abnormalities in the cytoskeleton.
Molecular mechanisms of dissociative glucocorticoid activity
Authors: Bamberger C. M. , Schulte H. M. 
Published: March 2003

BackgroundGlucocorticoids mediate their effects on target cells via transactivation and transrepression of certain target genes. While conventional glucocorticoids do not distinguish between transactivation and transrepression, new glucocoticoids should be able to dissociate these effects, thus lowering the potential of unwanted side‐effects of glucocorticoids in clinical use. In this study, we developed a new experimental system to test potentially selective glucocorticoids in normal lymphocytes.Materials and methodsFollowing pretreatment with phytohaemagglutinin, normal lymphocytes were transfected, using electroporation, with pGL3 luciferase reporter vectors under the control: (1) of the human IL‐2 promoter; and (2) of a glucocorticoid response element (GRE). Luciferase activity was measured in response to various steroid compounds, including the potentially dissociative glucocorticoid medroxyprogesterone acetate (MPA).ResultsThe IL‐2 promoter was induced 267.2 ± 27.5‐fold (mean ± SD) by phorbol ester and ionomycin. In these cells, hydrocortisone and dexamethasone caused a 22.9 ± 3.6% and a 38.4 ± 10% reduction in luciferase activity, respectively. Under GRE control, hydrocortisone stimulated luciferase activity 6.4 ± 0.50‐fold and dexamethasone 8.2 ± 0.4‐fold. MPA‐induced transrepression was 73.3 ± 7.2% for the IL‐2 promoter, and transactivation was 2.4 ± 0.4‐fold with the GRE‐driven construct. The natural progestin progesterone did not have significant effects on either construct.ConclusionsThis is the first system that allows efficient analysis of glucocorticoid‐dependent transactivation and transrepression in normal human lymphocytes. Compared to conventional glucocorticoids, MPA can be reffered to as a dissociative glucocorticoid, its transrepression/transactivation ratio being 6.6 (transrepression 1.91/transactivation 0.29), with dexamethasone being the standard (transrepression 1/transactivation 1). We conclude that MPA is a highly promising substance for the treatment of autoimmune/inflammatory diseases.
Oral supplementation with whey proteins increases plasma glutathione levels of HIV‐infected patients
Authors: Micke P. , Beeh K. M. , Schlaak J. F. , Buhl R. 
Published: March 2003

HIV infection is characterized by an enhanced oxidant burden and a systemic deficiency of the tripeptide glutathione (GSH), a major antioxidant. The semi‐essential amino acid cysteine is the main source of the free sulfhydryl group of GSH and limits its synthesis. Therefore, different strategies to supplement cysteine supply have been suggested to increase glutathione levels in HIV‐infected individuals. The aim of this study was to evaluate the effect of oral supplementation with two different cysteine‐rich whey protein formulas on plasma GSH levels and parameters of oxidative stress and immune status in HIV‐infected patients.In a prospective double blind clinical trial, 30 patients (25 male, 5 female; mean age (± SD) 42 ± 9·8 years) with stable HIV infection (221 ± 102 CD4 + lymphocytes L−1) were randomized to a supplemental diet with a daily dose of 45 g whey proteins of either Protectamin (Fresenius Kabi, Bad Hamburg, Germany) or Immunocal (Immunotec, Vandreuil, Canada) for two weeks. Plasma concentrations of total, reduced and oxidized GSH, superoxide anion (O2–) release by blood mononuclear cells, plasma levels of TNF‐α and interleukins 2 and 12 were quantified with standard methods at baseline and after therapy.Pre‐therapy, plasma GSH levels (Protectamin: 1·92 ± 0·6 μM; Immunocal: 1·98 ± 0·9 μM) were less than normal (2·64 ± 0·7 μM, P = 0·03). Following two weeks of oral supplementation with whey proteins, plasma GSH levels increased in the Protectamin group by 44 ± 56% (2·79 ± 1·2 μM, P = 0·004) while the difference in the Immunocal group did not reach significance (+ 24·5 ± 59%, 2·51 ± 1·48 μM, P = 0·43). Spontaneous O2– release by blood mononuclear cells was stable (20·1 ± 14·2 vs. 22·6 ± 16·1 nmol h−1 10−6 cells, P = 0·52) whereas PMA‐induced O2– release decreased in the Protectamin group (53·7 ± 19 vs. 39·8 ± 18 nmol h−1 10−6 cells, P = 0·04). Plasma concentrations of TNF‐α and interleukins 2 and 12 (P > 0·08, all comparisons) as well as routine clinical parameters remained unchanged. Therapy was well tolerated.In glutathione‐deficient patients with advanced HIV‐infection, short‐term oral supplementation with whey proteins increases plasma glutathione levels. A long‐term clinical trial is clearly warranted to see if this ‘biochemical efficacy’ of whey proteins translates into a more favourable course of the disease.
Somatostatin receptor subtype 2 and 5 in human GH‐secreting pituitary adenomas: analysis of gene sequence and mRNA expression
Authors: Corbetta S. , Ballaré E. , Mantovani G. , Lania A. , Losa M. , Di Blasio A. M. , Spada A. 
Published: March 2003

The role of somatostatin receptor subtypes 2 and 5 (SSTR2 and SSTR5) in determining the secretory and proliferative phenotype as well as the sensitivity to somatostatin analogue treatment is not clearly established.We quantified the expression of SSTR2 and SSTR5 mRNA using a semiquantitative reverse transcription‐polymerase chain reaction (RT‐PCR) in 19 human growth hormone (GH) ‐secreting adenomas. Tumour characteristics and in vivo sensitivity to somatostatin analogues were assessed; tumours were screened for Gsα gene mutations. PCR products of SSTR2 and SSTR5 DNA from tumours resistant to somatostatin analogues were directly sequenced.All tumours expressed both SSTR2 and SSTR5 mRNA at variable levels. No significant correlation between SSTR2 and SSTR5 expression and the presence of Gsα mutation, GH levels, or tumour size and invasiveness was observed. A negative correlation between SSTR2 and SSTR5 mRNA levels was observed (r = 0·5; P < 0·05). No significant correlation between the levels of SSTR2 and SSTR5 expression and the in vivo responsiveness to somatostatin analogues was observed, although a tendency to a low SSTR2 expression in resistant tumours was found. No mutations in the coding or bordering regions of either SSTR2 or SSTR5 adenomatous DNA from patients totally or partially resistant to somatostatin analogues were found.The study shows that the different expression of SSTR2 and SSTR5 in GH‐secreting adenomas is not significantly correlated with the secretory and proliferative phenotype, although the large, hypersecretory tumours and those with a poor sensitivity to somatostatin analogues seem to express low levels of SSTR2 mRNA. Moreover, both SSTR2 and SSTR5 DNA from tumours resistant to somatostatin analogues were found to possess intact coding sequences.
Levels of vasodilators (SP, CGRP) and vasoconstrictor (NPY) peptides in early human burns
Authors: Onuoha G. N. , Alpar E. K. 
Published: March 2003

An intact nociceptor system of primary afferent sensory nerves is important for the initiation of the inflammatory process and successful tissue repair. Dysfunction of this system could be a contributing factor for delayed wound healing in humans. We examined the levels of vasodilators [substance P (SP), calcitonin gene‐related peptide (CGRP)] and a vasoconstrictor peptide [neuropeptide Y (NPY)] in the peripheral blood samples of patients with burns covering from 20 to 75% of body surface area.Thirteen patient samples were obtained immediately on admission (OA), which was within 12 h of the thermal injury, and 24 h post‐admission (PA). Enzyme immunoassay techniques were used for the measurement of the neuropeptides. In addition, an inflammatory marker, tumour necrosis factor‐α (TNF‐α), and a myofibrillar protein, creatine kinase (CK), were examined and compared with levels in 13 control subjects.CGRP was high OA and the levels were maintained PA (P < 0·05). SP was also significantly high at both sampling times (P < 0·05). Although TNF‐α and NPY were somewhat higher in the patients' samples than in the control samples, these levels were not statistically significant (P = NS). CK was higher OA (P < 0·01) than PA (P < 0·04), compared to controls.Plasma levels of SP and CGRP increased significantly in patients with thermal injuries. These peptides may yet be another group of neuromodulators playing a significant role in immune, pain, inflammatory and wound healing in burns.
Fecal elastase‐1 is decreased in villous atrophy regardless of the underlying disease
Authors: Walkowiak J. , Herzig K‐H. 
Published: March 2003

Background Fecal elastase‐1 (E1) is a sensitive and reliable test in the assessment of exocrine pancreatic function in cystic fibrosis (CF). In patients with celiac disease (CD), different E1 values have been reported. E1 levels in other malabsorption conditions are unknown. Therefore, the aim of the present study was to evaluate E1 concentrations in various malabsorption syndromes.Material and methods The study was carried out in 54 patients, selected from patients referred with suspicion of CF, who had been diagnosed as celiac disease (CD; n = 16), secondary malabsorption syndrome (SMS, giardiasis‐ or cow milk‐related enteropathy; n = 18) and food allergy (FA; n = 20). 70 age‐matched healthy children (HC) and 131 cystic fibrosis (CF) patients served as control groups. In CD and SMS patients, a gluten‐free diet was introduced. In addition, SMS patients were treated appropriately to underlying disease. In all subjects, E1 concentrations were measured. In CD and SMS patients, E1 concentrations were repeatedly measured after one year of the treatment.Results With a cut‐off level of 200 µg g−1, abnormal E1 concentrations were found in 87·2% of the CF group and in 56·2% and 50·0% of the CD and SMS subgroups, respectively. In none of FA patients, were E1 values below the normal range. After mucosal recovery, E1 concentrations in patients with CD and SMS increased, suggesting that villous atrophy can diminish exocrine pancreatic secretion. In 18 out of 19 CD and SMS patients with abnormal E1 concentrations, monitored for at least 12 months of a gluten‐free diet, abnormal E1 concentrations increased above the cut‐off value to normal range. Two out of the 54 referred patients were finally diagnosed as having CF, one with stable low E1 levels and the second with finally normal values.Conclusions The exocrine pancreatic function is decreased in villous atrophy regardless of underlying disease. The specificity of the fecal elastase‐1 test in the differentiation between ‘primary’ exocrine pancreatic insufficiency and intestinal malabsorption with mucosal atrophy is low. After mucosal regeneration, fecal elastase‐1 specificity is high.