Local and Systemic Liberation of Proinflammatory Cytokines in Ulcerative Colitis

Determination of plasma and tissue cytokinelevels in inflammatory bowel disease have frequentlyresulted in conflicting data. In the present study wedetermined in patients with ulcerative colitis (UC), the levels of the proinflammatory cytokinesinterleukin (IL)-1, IL-6, interferon(IFN)-, and tumor-necrosis factor (TNF)-liberated by peripheral blood mononuclear cells (PBMC)and lamina propria mononuclear cells (LPMC) after 48-hrculture with pokeweed mitogen (PWM). IL-1, IL-6,IFN- and TNF- in the supernatant weredetected by ELISA. Results show low basal levels ofIL-1 secretion by PBMC and LPMC, and a considerableincrease after mitogen stimulation. Basal IL-6production by PBMC was higher in UC patients than incontrols [2029 pg/ml, CI₉ (–165 to4223) vs 572 pg/ml (–383 to 1527) respectively, P = 0.05] and also afterPWM activation [14,995 pg/ml (7759 -22230) vs 6598 pg/ml(3240-9956), respectively, P = 0.05]. In LPMC, nodifferences in IL-6 secretion were observed. TNF- in activated PBMC of patients with UC was notsignificantly increased in relation to control (P =0.09). No constitutive secretion of IFN- wasobserved in mononuclear cells. IFN- levelssecreted by activated LPMC were lower in patients withUC than in controls [1571 pg/ml (–108 to 3251) vs7953 pg/ml (3851-12,055), respectively, P = 0.03]. Theseresults suggest that IL-6, IL-1, and TNF- participate as mediators in the inflammatoryphenomena observed in UC. Further studies are necessaryto evaluate the role of IFN- in thiscondition.     

Type I diabetes mellitus

Summary The major genetic susceptibility to insulin dependent (Type 1) diabetes is determined by genes in the HLA chromosomal region. An increased relative risk for developing the disease is observed in subjects who are HLA A1, A2, B8, B18, B15, B40, CW3, Bf^s, DW3, DW4, DRW3, DRW4 positive. There is an additive relative risk in subjects who possess two high risk HLA B alleles which has an important influence on the prevalence of the disease in sibships and possibly on the concordance rate in diabetic identical twins. There is also suggestive evidence that particular combinations of high risk HLA B alleles are associated with increased or persistent antibody production which may reflect enhanced or differential susceptibility. Certain factors (e. g. HLA B7, DW2 and DRW2) are associated with a significantly reduced risk and may exert a protective mechanism in Type I diabetes, by linkage disequilibrium with genes which reduce immune responsiveness. The significant increases and decreases in respect of the HLA B antigens are probably secondary to the corresponding HLA D and DRW associations which reflect a stronger linkage disequilibrium between the genes which determine these specificities and the putative genes which control susceptibility. Initial damage to the beta cells probably occurs a considerable time before the onset of symptoms and theoretically modification of the immune response early in the disease process may reduce the rate of beta cell destruction.     

The effects of parabiosis on serum and kidney glycosidase activities in spontaneously diabetic mice

Summary Spontaneously diabetic non-obese mice of the ICR strain were newly inbred in Shionogi laboratory, Japan. Animals became diabetic suddenly, more frequently and severely in females. Blood glucose levels were 452±73 mg/100 ml with serum insulin levels of < 1.0 U/ml in the fed state. Parabiosis with normal control ICR mice for 2 weeks decreased the blood glucose level to 260±51 mg/ 100ml (P<0.01) and resulted in serum insulin levels of 46.0±18.0 U/ml (P<0.01). Kidney homogenate -N-acetylglucosaminidase and -galactosidase activities were reduced in diabetic mice (42% and 44% decrease respectively) (P<0.025 and P<0.001), and restored almost to normal after 2 weeks of parabiosis. Renal -mannosidase activity was decreased 43% (P<0.001) in the diabetic mice but unaffected by parabiosis. Serum -N-acetylglucosaminidase, -galactosidase and -glucosidase activities were significantly increased in diabetic mice (179%; 233% and 58% increase respectively) (P<0.005, P<0.001 and P<0.001), and returned to normal with parabiosis.     

Direct Evidence of Gonadotropin-Releasing Hormone (GnRH)-Stimulated Nitric Oxide Production in the LβT-2 Clonal Gonadotropes

An immortal cell line (LT-2) with characteristics of gonadotropes, such as LH-containing secretory granules, and LH release responsiveness to GnRH, was used to investigate the effect of GnRH stimulation on nitric oxide (NO) production. RT-PCR analysis showed that mouse nNOS mRNA was expressed in cultured LT-2 cells. LT-2 cells were treated with the calcium ionophore, A23187, and NO levels were measured as nitrite using the Griess assay. The data clearly showed that NO production was increased dose-dependently by A23187 treatment (0–10^-5 M). Next, changes in the intracellular concentration of ionized calcium ([Ca²⁺]_i) in LT-2 cells induced by GnRH were analyzed by quantitative fluorescence microscopy, and [Ca²⁺]_i was found to be increased markedly by GnRH treatment. In fact, exposure of LT-2 cells to increasing concentrations of GnRH from 0 to 10^-6 M was found to enhance NO production in a dose dependent manner, with maximal augmentation at 10^-6 M. However, the stimulation of NO production by GnRH at this concentration was significantly attenuated by pretreatment with N^G-nitro-L-arginine methyl ester hydrochloride (L-NAME), a NO synthase inhibitor.Taken together, the present results suggest that GnRH treatment results in increased NO production in LT-2 clonal gonadotropes, and intracellular calcium augmentation produced by GnRH may be participate in this process. Our findings also indicate that the LT-2 cell line is a useful tool for in vitro studies of the autocrine and paracrine roles of NO in the anterior pituitary gland.     

Bone marrow and peripheral blood globin chain biosynthesis in iron deficiency

Summary Globin chain synthesis was studied in 13 iron-deficient patients. The mean whole-cell globin / ratio in the peripheral blood of 11 patients was 1.05±0.06 which is similar to the value 0.99±0.08 obtained for 10 controls. The ratios odtained for stroma-free globin were not significantly different from those of whole cell preparations. In contrast, the / ratio of bone marrow was 0.73±0.14 in 10 iron deficient patients, which is significantly lower than that of controls. Two other patients had decreased / ratios in the peripheral blood, probably because of the presence of an -thalassemia gene. These results demonstrate a reduced rate of synthesis of chains relative to that of chains in the bone marrow of iron-deficient patients that is not demonstrable in the peripheral blood.This work was partly supported by Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil     

Influence of insulin on cyclic 3′,5′-AMP phosphodiesterase activity in liver,skeletal muscle,adipose tissue,and kidney

Summary Influence of insulin on liver glycogen metabolism and on lipolysis appears to be mediated by a decreased intracellular 3,5-AMP concentration. Reduced formation of 3,5-AMP had been shown in adipose tissue incubated with insulin. The influence of insulin on 3,5-AMP degradation has been investigated. — 3,5-AMP phosphodiesterase (PDE) activity was reduced in liver, adipose tissue and, insignificantly, in skeletal muscle of insulin deficient, i.e. alloxan diabetic or starved rats. I.V. injection of a low dose of insulin (0.5 U/kg) or stimulation of endogenous insulin secretion by injection of glucose led to a rapid increase of PDE activity in these tissues. 15 min after insulin injection liver PDE activity was increased. The maximal effect occurred after 30–45 min. Renal PDE activity was not decreased in alloxan diabetes, insulin injection has been found ineffective. —In vitro, there was an activating effect of crystalline insulin on PDE purified from beef heart. Insulin concentration required for duplication of enzyme activity was of the order of 2 · 10^–5 M. Treatment with actinomycin D nearly prevented stimulation of liver PDE by insulin. This may indicate that the action of insulin on PDE activity is essentially based on an increased enzyme synthesis. — Owing to the influence of insulin secretion on liver and adipose tissue 3,5-AMP concentration, glycogen metabolism and lipolysis can be quickly adapted to food intake.

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Der Einfluß von Insulin auf die 3,5-AMP-Phosphodiesterase-Aktivität in Leber, Skeletmuskulatur, Fettgewebe und Niere

Zusammenfassung An der Steigerung der Glykogensynthese der Leber und der Verminderung der Lipolyse durch Insulin ist eine Abnahme der 3,5-AMP-Konzentration wesentlich beteiligt. Die 3,5-AMP-Bildung ist in Fettgewebe, das mit Insulin inkubiert wird, vermindert. Insulin beeinflußt jedoch auch den 3,5-AMP-Abbau. -Die 3,5-AMP-Phosphodiesterase (PDE)-Aktivität des Fettgewebes, der Leber und, in geringerem Grade, der Skeletmuskulatur ist im Insulinmangel vermindert, d.h. bei alloxandiabetischen oder hungernden Ratten. I.v. Injektion von 0,5 E/kg Insulin oder eine erhöhte Abgabe von Insulin aus dem Pankreas nach Glucoseinjektion führen in diesen Geweben zu einem raschen Anstieg der PDE-Aktivität. Dieser ist in der Leber schon 15 min nach Insulingabe nachweisbar und erreicht nach 30–45 min sein Maximum. In der Niere ist kein Einfluß von Insulin auf die PDE-Aktivität nachweisbar. — Aus Rinderherz isolierte PDE wirdin vitro durch Insulin aktiviert, jedoch werden2 · 10^–5 M zur Verdopplung der Aktivität benötigt. Actinomycin D verhindert die Steigerung der Leber-PDE-Aktivität nach Insulininjektion. So kann die Wirkung des Hormons im wesentlichen auf eine gesteigerte PDE-Synthese zurückgeführt werden. — Durch diesen Einfluß der Insulininkretion auf die 3,5-AMP-Konzentration in Leber und Fettgewebe können Glykogenstoffwechsel und Lipolyse rasch an die Nahrungsaufnahme angepaßt werden.

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Influence de l'insuline sur l'activité de la 3,5-AMP-phosphodiestérase dans le foie, le muscle strié, le tissu adipeux et le rein

Résumé L'influence de l'insuline sur le métabolisme du glycogène hépatique et sur la lipolyse semble s'exercer par l'intermédiaire d'une diminution de la concentration de 3,5-AMP intracellulaire. Onamontré une diminution de la formation de 35-AMP dans le tissu adipeux incubé avec de l'insuline. L'influence de l'insuline sur la dégradation du 3,5-AMP est étudiée. — L'activité de la 3,5-AMP-phos-phodiestérase (PDE) est diminuée dans le foie, le tissu adipeux et, de façon non-significative, dans le muscle strié des rats qui manquent d'insuline, c-à-d les rats rendus diabétiques par l'alloxane ou les rats privés de nourriture. L'injection intraveineuse d'une faible dose d'insuline (0.5 U/kg) ou la stimulation de la sécrétion d'insuline endogène par une injection de glucose provoquent une augmentation rapide de l'activité de la phosphodiestérase dans ces tissus. 15 min après l'injection d'insuline, l'activité de la phosphodiesterase du foie est augmentée. L'effet maximum est atteint après 30–45 min. L'activité de la phosphodiestérase rénale n'est pas diminuée dans le diabète alloxanique, l'injection d'insuline s'est avérée inefficace.In vitro, l'insuline cristalline a un effet activant sur la phosphodiestérase purifiée du coeur de boeuf. La concentration d'insuline requise pour doubler l'activité de l'enzyme est de l'ordre de 2 · 10^–5 M. Le traitement avec actinomycin D empêche la stimulation par l'insuline de la PDE dans le foie. Ceci peut indiquer que l'action de l'insuline sur l'activité de la phosphodiestérase est essentiellement basée sur une synthèse accrue de l'enzyme. A cause de l'influence de la sécrétion d'insuline sur la concentration en 3,5-AMP du foie et du tissu adipeux, le métabolisme du glycogène et la lipolyse peuvent s'adapter rapidement à la prise de nourriture.

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Non-Standard Abbreviations G 6 P Glucose-6-phosphate - UDPG UDP-glucose - FFA non-esterifled, free fatty acids - 3,5-AMP cyclic adenosine-3,5-monophosphate - PDE 3,5-AMP phosphodiesterase This study was supported by the Deutsche Forschungsgemeinschaft.Deceased October 31, 1967.     

γ/δ Receptor-expressing T-cell clones from a cutaneous T-cell lymphoma suppress hematopoiesis

Summary Recently we described a cutaneous T-cell lymphoma expressing the / T-cell receptor [5]. The patient suffering from this lymphoma showed low numbers of myeloid and T cells in peripheral blood, while B and NK cells were relatively increased. In vitro culture of the patient's bone marrow (BM) cells revealed a significant suppression of myeloid/monocyte colony formation (GM-CFU) compared with normal controls. This was not due to infiltration of the BM with lymphoma cells. We speculated that a soluble factor either secreted or induced by the lymphoma cells might be responsible for the marked suppression of hematopoiesis in this patient. From a skin biopsy with infiltrating / T-lymphoma cells we established T-cell clones bearing the / T-cell receptor and resembling the phenotype of the lymphoma cells. The supernatant (SN) of these / T-cell clones reduced the number of colonies in a CFU-GM assay (using normal control BM) in comparison to SN of / T-cell clones established from the same biopsy. This suppression was seen mainly on day 7 of culture and was not neutralized by the addition of placenta-CM. The main mediator of this suppression seems to be IFN-,since it was detectable in high amounts in the SN of these / T-cell tumor clones as well as in the serum of the patient. In addition, anti-IFN- antibodies can reverse the T-cell SN-mediated suppression of CFU-GM. We conclude that high serum levels of interferon-, which is secreted in high amounts from / T-cells grown from a biopsy of a cutaneous lymphoma, can suppress hematopoiesis.Abbreviations TCR T-cell receptor - IFN- interferon- - SN supernatant - placenta CM placenta conditioned medium - BM bone marrow - CFU-GM myeloid/monocyte colony formation - NK cells natural killer cells - Ab antibody M. Wilhelm was supported by theDeutsche Forschungsgemeinschaft (DFG Wi 728-2)     

Changes in the hydroxyproline,hexosamine and sialic acid of the diabetic human and β, β′-iminodipropionitrile-treated rat retinal vascular systems

Summary The retinal vasculature has been isolated from nondiabetic and diabetic post mortem human eyes by controlled trypsin digestion. Chemical analysis demonstrated increases in the hydroxyproline and hexosamine contents in diabetes. There was no general increase in the sialic acid content. These results have been related to histological preparations of sectors of the same retinas. Administration of, -iminodipropionitrile to rats caused a retinopathy characterised by endothelial cell proliferation, increased PAS-positivity and microaneurysms. Chemical analysis of retinal vascular systems from, -iminodipropionitrile-treated rats revealed increases in hydroxyproline, hexosamine and sialic acid contents.

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Änderungen des Gehaltes an Hydroxyprolin, Hexosamin und N- azetyl- Neuraminsäure in den Netzhautgefäen von menschlichen Diabetikern und mit , Iminodiproprionitril behandelten Ratten

Zusammenfassung Die Netzhautgefäße wurden post-mortal aus diabetischen und nichtdiabetischen Augen mit Hilfe einer kontrollierten Trypsin-Behandlung gewonnen. Bei der chemischen Analyse fand sich ein Anstieg des Hydroxyprolin- und Hexosamingehaltes in den diabetischen Augen. Der N-azetyl-Neuraminsäuregehalt war im allgemeinen nicht erhöht. Diese Resultate wurden in Beziehung gebracht zu den histologischen Befunden, die an den einzelnen Sektoren der gleichen Retina erhoben wurden. Verabreichung von, -Iminodiproprionitril an Ratten bewirkte eine Retinopathie unter den Zeichen einer Wucherung der Endothelzellen, verstärkter PAS-Anfärbbarkeit und Mikroaneurysmen. Die chemische Analyse der Netzhautgefäße von mit, -Iminodiproprionitril behandelten Ratten zeigte einen erhöhten Gehalt an Hydroxyprolin, Hexosamin und N-azetyl-Neuraminsäure.

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Variations de l'hydroxyproline, de l'hexosamine et de l'acide sialique dans les systèmes vasculaires rétiniens de l'homme diabétique et du rat traité par le , -iminodipropionitrile

Résumé Le système vasculaire rétinien a été isolé, par digestion trypsique contrôlée, après la mort, à partir d'yeux humains de non-diabétiques et de diabétiques. L'analyse chimique a révélé l'augmentation du contenu en hydroxyproline et en hexosamine, dans le diabète. Il n'y avait pas d'augmentation générale du contenu en acide sialique. Ces résultats ont été rapprochés des préparations histologiques de portions des mêmes rétines. L'administration de, -iminodipropionitrile à des rats provoquait une rétinopathie caractérisée par une prolifération des cellules endothéliales, une PAS-positivité augmentée et des microanévrismes. L'analyse chimique des systèmes vasculaires rétiniens des rats traités par le,-iminodipropionitrile, a révélé l'augmentation du contenu en hydroxyproline, en hexosamine et en acide sialique.

     

On the pathogenesis of preleukemic myelodysplastic syndromes

Summary After a single pulse dose of DMBA, rats develop bone-marrow hypoplasia, which is almost compensated for by regeneration after 16 weeks. Subsequently, dysplastic signs of hemopoiesis appear in all experimental animals as massive extrusion of normoblasts into the peripheral blood, red-cell anisoand poikilocytosis, nuclear deformities, atypical mitoses, and PAS-positivity, as well as megaloblastoid maturation dissociation of erythroblasts and nuclear and granulation anomalies of neutrophilic granulocytes and monocytes, comparable to human pseudo-Pelger cells and paraneutrophils. At the time of death (112-497 days after DMBA pulse) experimental animals showed hyperplastic bone marrow with increased granulopoietic/erythropoietic ratios and an augmented, mainly erythropoietic, hemopoiesis in the spleen, with splenomegaly in six rats. Splenic hemopoiesis is accompanied by white pulp atrophia. The cause of death was septicopyemia in three rats, anemia in three, and bleeding in one rat. None of the animals developed a leukemic blast phase. Myelodysplastic changes in this experiment are the same as have been shown to precede leukemia in rats treated with five DMBA pulses (Fohlmeister et al. 1981). Possible relations of myelodysplasia and leukemia are discussed.Supported by Deutsche Forschungsgemeinschaft (DFG)     

A Czechoslovakian teenager with Hb E-β∘-thalassemia [IVS-I-1 (G → A)] complicated by the presence of an α-globin gene triplication

Summary We have examined the molecular basis of three inherited hemoglobin (Hb) disorders present in a Czechoslovakian girl with a severe, transfusion-dependent, hemolytic anemia. She is heterozygous for Hb E (on a genetic background specific for Czechoslovakian families), heterozygous for the -thalassemia (thal) allele IVS-I-1 (G A), and heterozygous for an -globin gene triplication. The combination of these three undesirable traits results in a severe chain imbalance that is the basis of the serious hemolytic disorder observed in this teenager.This study was supported in part by USPHS Research Grant HLB-41544. This is contribution 1282 from the Department of Cell and Molecular Biology at the Medical College of Georgia in Augusta     

Direct mutation analysis of β-thalassemia genes in families of various ethnic origins residing in Germany

Summary DNA from Mediterranean and Asian -thalassemia patients, now residing in Germany, has been characterized by oligonucleotide hybridization and direct restriction analysis. Using five oligonucleotide pairs complementary to the most frequent -thalassemia mutations, and three different restriction enzymes, we were able to detect 33 of 36 mutations directly.     

Rapid molecular characterization of mutations leading to unstable hemoglobin β-chain variants

Summary Characterization of unstable hemoglobins by protein analysis is often difficult. However, it is facilitated by DNA analysis, especially in the case of hyperunstable -chain variants, which produce a -thalassemia phenotype. We have applied an efficient strategy to the detection of such variants at the DNA level, based on computer-designed denaturing gradient gel electrophoresis (DGGE) of amplified DNA fragments. This approach makes it possible to detect any anomaly in the -globin gene. We describe the use of the DGGE method for rapid characterization of -chain variants and report a new missense mutation in the -globin gene third exon, 127 CAG-CGG/Gln-Arg, which is responsible for the synthesis of a highly unstable hemoglobin.     

Macrophages enhance binding of beta-VLDL and cholesterol ester accumulation in cultured aortic smooth muscle cells

Summary The effect of macrophages on the uptake of -very low-density lipoprotein (-VLDL) by smooth muscle cells (SMC) expressing different morphological phenotypes was examined in culture. The SMC were grown alone and in co-culture with macrophages for four days, then incubated with different concentrations of¹²⁵I--VLDL for 3 h at 4°C or with 75 ug/ml -VLDL for 24h at 37°C. The binding of -VLDL to SMC at 4°C was enhanced in the presence of macrophages irrespective of the phenotype expressed by SMC. This occurred through modification of the lipoprotein, since binding of re-isolated macrophage-conditioned -VLDL to SMC was 12.5 times that of fresh -VLDL. This modified form of -VLDL competed with fresh -VLDL for binding to SMC. Binding was inhibited in the presence of probucol, suggesting that an oxidative mechanism may be involved.The presence of macrophages also enhanced the accumulation of -VLDL-derived cholesterol in SMC. While most of this is a consequence of the enhanced binding, macrophages may also act directly on SMC to increase cholesterol accumulation, since the activity of acid cholesterol ester hydrolase and neutral cholesterol ester hydrolase in SMC was reduced in the presence of macrophages.     

Involvement of α2-Adrenoceptors in mechanism of intragastric nicotine protection against ethanol injury in rat stomach

To elucidate the role of - and -adrenoceptors in the mechanism of intragastric nicotine protection against ethanol-induced gastric mucosal injury, the following studies were performed. At 0.5-hr prior to the injury study, rats were pretreated with: subcutaneous control, prazosin (0.5 mg/kg) or yohimbine (5 mg/kg) to block ₁- or ₂-adrenoceptors; or intraperitoneal control, metoprolol (2 mg/kg) or butoxamine (4 mg/kg) to block ₁- or ₂-adrenoceptors, respectively. At 1-hr intervals, rats received intragastric vehicle or nicotine (4 mg/kg) and 40% ethanol (10 ml/kg). Total lengths of the linear gastric corpus mucosal lesions were measured by an unbiased observer using a caliper. In a separate study, 0.5-hr after subcutaneous control or yohimbine (5 mg/kg), rats were treated with intragastric vehicle or nicotine (4 mg/kg). One hour later, gastric mucus volume, gastric juice volume and pH, and titratable acid in the gastric juice were measured. In the rat stomach, the intragastric nicotine protection against 40% ethanol-induced mucosal injury was not blocked by selective ₁-(prazosin), ₁-(metoprolol), or ₂-(butoxamine) adrenoceptor antagonists. The protection was significantly reduced although not completely abolished by selective ₂-(yohimbine) adrenoceptor antagonist. Yohimbine also significantly reduced basal and nicotine-stimulated increase in gastric mucus volume. These data suggest that ₂-adrenoceptors are involved in the protective effect of intragastric nicotine against 40% ethanol-induced gastric mucosal injury possibly by a mucus-dependent mechanism.Supported by Veternas Administration Medical Research Funds, and in part by research grants (0162-01, 02, and 291-01) from the Smokeless Tobacco Research Council, Inc., and by funds (1RT 80) provided by the Cigarette and Tobacco Surtax Fund of the State of California through the Tobacco-Related Disease Research Program of the University of California to F.W.L. Dr. Endoh is a recipient of the University of California Tobacco-Related Disease Research Program Research Fellowship Award (FT 37).     

Anti-cardiolipin and Anti-β2-glycoprotein I Antibodies in Patients with Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD)frequently suffer from thromboembolic events.Anti-cardiolipin (aCL) antibodies have been shown to beassociated with thrombosis. Recently, the antibodies against the anti-cardiolipin cofactor₂-glycoprotein I(a₂GPI) have been found with higherspecificity for thrombosis. The presence of theseantibodies was assessed in 128 patients with IBD [83 with ulcerative colitis (UC) and 45 withCrohn's disease (CD)] and 100 healthy controls (blooddonors). Patients with UC and CD had a significantlyhigher prevalence of aCL (18.1% and 15.6%, respectively) than healthy controls (HC) (3%). Eleven IBDpatients (8.6%) but no HC had a₂GPI.None of the IBD patients with a history of thrombosishad aCL and only one of them (a UC patient with deepvein thrombosis of the right leg) had a high titer of IgGa₂GPI. In conclusion, these data showthat both aCL and a₂GPI aresignificantly associated with IBD but further studiesare needed to determine the significance of our findings.     

Triplication (/ααα<Superscript>Anti3.7</Superscript>) or deletion (-α<Superscript>3.7</Superscript>/) association in Argentinian β-thalassemic carriers

Prevalence of alpha gene triplication or deletion in -thalassemia carriers was studied in 109 unrelated individuals in Rosario, Argentina. In different populations -^3.7 allele presents a higher prevalence than ^anti3.7; thus, -thalassemia associated with -thalassemia is more frequently observed. Nevertheless, this event was detected in only one case (0.9%), while the association with alpha triplication was present in two subjects (1.8%).     

B cell adrenoceptors and sulphonylurea-induced insulin release in mouse islets

Summary Interactions of tolbutamide and glibenclamide with B cell adrenoceptors have been reported. This study evaluated the possible role of such interactions in the stimulation of insulin release. Mouse islets were incubated in the presence of 10 mmol/l glucose alone or with tolbutamide (10 mol/l) or glibenclamide (0.02 mol/l). At 0.01–10 mol/l, blockers of ₂-adrenoceptors (yohimbine, idazoxan) or ₁-adrenoceptors (prazosin) had practically no effect on glucose-induced insulin release and did not affect its potentiation by sulphonylureas, except for a slight increase by 10 mol/l prazosin and idazoxan. Nonspecific -blockers (phentolamine, dihydroergotamine) increased control release at 10 mol/l, but only the latter amplified the response to tolbutamide. Blockers of -adrenoceptors were tested at 0.1–100 mol/l: propranolol (₁, ₂), metoprolol (₁) and compound ICI 118-551 (₂). They increased glucose-induced insulin release at 100 mol/l but variably altered the effect of sulphonylureas. Blockers of adrenoceptors have, thus, no effect on insulin release in vitro at therapeutic concentrations. At high concentrations, they non-specifically affect the action of sulphonylureas. We conclude that an interaction with B cell adrenoceptors is not involved in the insulinotropic action of sulphonylureas.     

Localization of transforming growth factor-β 1 precursor and latent TGF-β 1 binding protein in colorectal adenomas

Transforming growth factor- ₁ (TGF- ₁) is a multifunctional cytokine and is thought to be involved in colorectal tumorigenesis as a regulator of cell growth and differentiation. This role is mainly supported byin vitro studies while its rolein vivo remains unclear. The aim of the present study was to investigate whether the TGF- ₁ precursor ( ₁-LAP) and the latent TGF- ₁ binding protein (LTBP) are expressed in colorectal adenomas, the presumed precursors of most of colorectal adenocarcinomas. TGF- ₁ precursor and LTBP were examined in 35 adenomas and 10 normal colonic mucosa specimens by immunohistochemistry, using specific polyclonal antibodies. In normal colonic mucosa, ₁-LAP was moderately expressed in epithelial crypt cells and in the stromal cells in the lamina propria. In adenomas, ₁-LAP was localized in epithelial cells with an heterogeneous pattern and was also present in stromal cells around the adenomatous glands. LTBP was not detected in epithelial cells but was observed in stromal cells and in the extracellular matrix (ECM). ₁-LAP expression in epithelial cells did not correlate with the grade of dysplasia, while LTBP localized in stromal cells and ECM appeared to be closely associated with areas of higher grade of dysplasia. This study is the first demonstration of both ₁-LAP and LTBP in colorectal adenomas with different dysplasia grades. Our results suggest that TGF- ₁ might be involved in the mechanisms controllingin vivo colorectal tumorigenesis and support a role for the stromal-associated TGF- ₁.J.-L. Van Laethem is supported by a grant of the Fondation Erasme (Brussels, Belgium).     

Gabexate mesilate, a synthetic protease inhibitor, attenuates carbon tetrachloride-induced liver injury in rats

Background Gabexate mesilate, a synthetic protease inhibitor, is used to treat acute pancreatitis and disseminated intravascular coagulation because it inhibits various serine proteases; however, whether gabexate mesilate prevents acute liver failure has not yet been studied. The aim of the present study was to investigate the effect of gabexate mesilate in carbon tetrachloride (CCl₄)-induced liver injury in rats.Methods Acute hepatic failure was induced by administration of CCl₄ intragastrically to male Sprague–Dawley rats. The effects of gabexate mesilate were examined in terms of serum transaminase levels, liver histology, and the prognosis of rats.Results Gabexate mesilate treatment significantly decreased the elevation of serum transaminase levels and improved liver histology 24h after the administration of CCl₄ (0.2ml/100g rat weight). Plasma tumor necrosis factor- (TNF-) and interleukin-1 (IL-1) decreased significantly in the gabexate mesilate-treated rats compared with saline-treated rats. Gabexate mesilate treatment also significantly improved survival rate after a lethal dose of CCl₄ (0.5ml/100g rat weight) from 0% to 20%.Conclusions Gabexate mesilate treatment attenuated CCl₄-induced liver injury via a suppression of proinflammatory cytokine production. In addition, these investigations suggest that gabexate mesilate treatment may provide therapeutic strategies for human acute liver failure.     

Serum β2-Microglobulin in Chronic Hepatitis C

₂-Microglobulin(₂-MG) plays a key role in influencingthe immune response to viral infections as it is anintegrating part of the main histocompatibility system(HLA). We attempted to evaluate the changes in class I HLA antigens bycomparing the serum ₂-MG behavior in agroup of patients affected by chronic hepatitis C withthat observed in a group of healthy controls. Our studyrevealed that the patients presented higher serumbeta-MG levels than healthy controls (P = 0.0003).beta-MG levels were correlated with duration and degreeof the disease. Furthermore, there was a statisticallysignificant correlation between ₂-MG andHCV RNA levels, while no correlations were observedbetween serum ₂-MG levels and HCVgenotypes. The increment in serum ₂-MGvalues accompanying the progression of liver disease may be an expression ofaugmented production rather than alteredexcretion.