TCR1+ large granular lymphocyte proliferation in rheumatoid arthritis

The T-lymphoproliferative syndrome is characterized by a proliferation of large granular lymphocytes (LGL). It is often associated with neutropenia, and in 30% of cases with rheumatoid arthritis (RA). Phenotypic analysis has demonstrated that in most cases of RA with T-proliferative disease, the LGL represent T cells with a clonal rearrangement of the / T cell receptor (TCR2). Here, three patients with / TCR1⁺ LGL proliferation suffering from long-standing arthritis and neutropenia are described. The first patient with RA showed an expansion of a heterogeneous CD2⁺ CD16⁺ CD56^- LGL population, of which 30% coexpressed TCR1 with V1 rearrangement. The second patient with ankylosing spondylitis and RA was suffering from proliferation of TCR1⁺ (V9^-, V1^-), CD2⁺ CD16^- CD56^- LGL with low coexpression of CD8. The third patient with RA was suffering from a proliferation of TCR1⁺ (V1⁺, V9^-) CD4^- CE8^- CD16^- CD56^- lymphocytes. On the basis of these unusual findings, the pathogenetic role of TCR1⁺ T cells in RA is discussed.     

Expression and prognostic roles of integrins and interleukin-1 receptor type I in patients with ductal adenocarcinoma of the pancreas

To Investigate the prognostic indicator, we examined the expression of ₆- and ₅- integrin and interleukin-1 receptor type I (IL-1RI) immunohistochemically, and analyzed the correlation between immunohistochemical findings and clinicopathological factors in pancreatic cancer. In patients with a strongly expressing ₆- integrin subunit or weakly expressing ₅₁-integrin in pancreatic cancer tissues there was a significant association with advanced TNM stage (P = 0.027 and 0.014, respectively), presence of liver metastases (P = 0.032 and 0.002, respectively), and poor prognosis (P = 0.0155 and 0.0056, respectively). In patients with a weakly expressing ₆ integrin subunit or weakly expressing ₅₁-integrin in noncancerous pancreatic tissues there was a significant association with poor prognosis (P = 0.0324 and 0.0396, respectively). Multivariate analysis demonstrated that strong expression of ₆- and weak expression of ₅₁-integrin were found to be independent prognosticators in pancreatic cancer patients. Our present results indicate that ₆₁- and ₅₁-integrin expression can be a significant prognostic indicator in pancreatic cancer.     

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.     

Inhibition of endogenous SHIP2 ameliorates insulin resistance caused by chronic insulin treatment in 3T3-L1 adipocytes

Aims/hypothesis SHIP2 is a physiologically important negative regulator of insulin signalling hydrolysing the PI3-kinase product, PI(3,4,5)P3, which also has an impact on insulin resistance. In the present study, we examined the effect of inhibiting the endogenous SHIP2 function on the insulin resistance caused by chronic insulin treatment.Methods The endogenous function of SHIP2 was inhibited by expressing a catalytically inactive SHIP2 (IP-SHIP), and compared with the effect of treatments designed to restore the levels of IRS-1 in insulin signalling systems of 3T3-L1 adipocytes.Results Chronic insulin treatment induced the large (86%) down-regulation of IRS-1 and the modest (36%) up-regulation of SHIP2. Subsequent stimulation by insulin of Akt phosphorylation, PKC activity, and 2-deoxyglucose (2-DOG) uptake was markedly decreased by the chronic insulin treatment. Coincubation with the mTOR inhibitor, rapamycin, effectively inhibited the proteosomal degradation of IRS-1 caused by the chronic insulin treatment. Although the coincubation with rapamycin and advanced overexpression of IRS-1 effectively ameliorated subsequent insulin-induced phosphorylation of Akt, insulin stimulation of PKC activity and 2-DOG uptake was partly restored by these treatments. Similarly, expression of IP-SHIP2 effectively ameliorated the insulin-induced phosphorylation of Akt without affecting the amount of IRS-1. Furthermore, the decreased insulin-induced PKC activity and 2-DOG uptake following chronic insulin treatment were ameliorated by the expression of IP-SHIP2 more effectively than by the treatment with rapamycin.Conclusions/interpretation Our results indicate that the inhibition of endogenous SHIP2 is effective in improving the state of insulin resistance caused by chronic insulin treatment.     

Regulatory role of eicosanoids in extracellular matrix overproduction induced by long-term exposure to high glucose in cultured rat mesangial cells

Summary Accumulation of extracellular matrix in the mesangium and altered renal eicosanoid synthesis are two prominent features of diabetic glomerular disease. We investigated the relationship between eicosanoid and extracellular matrix production in rat mesangial cells cultured under high glucose vs normal glucose conditions. Long-term exposure of rat mesangial cells to high glucose, but not to iso-osmolar mannitol, significantly increased extracellular matrix accumulation and gene expression and transforming growth factor- (TGF-) mRNA levels, and decreased prostaglandin (PG) E₂ synthesis without affecting production of either thromboxane (TX) B₂ or PGF₂, with respect to cells incubated in normal glucose. Addition of exogenous PGE₂ resulted in a dose-dependent reduction of matrix protein and mRNA levels and TGF- gene expression in cells cultured in either normal or high glucose conditions, whereas exposure to exogenous PGF₂ produced a significant increment in matrix production and matrix and TGF- gene expression in cells grown in normal glucose, but only a slight increase in those cultured in high glucose. Stimulation of endogenous endoperoxide metabolism towards PGE₂ and PGF₂ synthesis with FCE-22,178, a drug originally developed as TXA₂ synthase inhibitor, resulted in a dose-dependent decrease in matrix accumulation and matrix and TGF- gene expression which was suppressed by co-incubation with the cyclo-oxygenase inhibitor feno-profen blocking the FCE-22,178-enhanced PG production. In both cell lines, the rate of synthesis of TXA₂ was very low and the selective blockade of its synthesis (by two other TXA₂ synthase inhibitors, OKY-046 and Ridogrel) or action (by the TXA₂ receptor antagonist BM-13,177) did not alter matrix production or TGF- mRNA levels. These results suggest that the cyclo-oxygenase pathway is involved in the regulation of matrix changes induced by high glucose in rat mesangial cells; the reduced production of PGE₂ may enhance the synthesis or potentiate the effect of stimulators of ECM formation such as TGF-, whereas TXA₂ does not appear to be involved. These data also indicate that glucose-enhanced mesangial matrix accumulation may be prevented by exogenous PGE₂ or by drugs capable of increasing endogenous PGE₂ synthesis.Abbreviations AGE Advanced glycosylation end-products - ECM extracellular matrix - PG prostaglandin - RMC rat mesangial cells - TGF- transforming growth factor- - TX thromboxane - Cox cyclo-oxygenase     

Ectoenzymes on the surface of cells from human lymphoblastoid lines: 5′-Nucleotidase and phosphatase

Summary Activities of the ecto-enzymes 5-nucleotidase (5-N) and phosphatase were determined on the surface of intact cells from 15 different established lines of human B- and T-lymphoblasts. Whereas all the lines express phosphatase, 10 of the lines were negative for 5-N. 5-N-negative cell lines are found among B as well as T cells, and they do not carry cryptic enzyme activity. In a 5-N-positive line activity of this enzyme is correlated with growth showing a peak during the logarithmic phase. On the other hand, inhibition of 5-N does not change the growth curve of this line. Neuraminidase treatment of the cell surface brings about an increase in phosphatase but not in 5-N activity. 5-N of two B-cell lines and of human peripheral blood lymphocytes shows complete crossreactivity with an antiserum obtained against human placental 5-N. However, the enzyme of one lymphoma line with B-cell properties (EHR-A-Ramos) does not cross-react with this serum. The results are discussed with respect to suitability of these lymphoblast lines as model systems for the study of immunodeficiencies.With a financial support of the Deutsche Forschungsgemeinschaft (grants SFB 37, Gu 123 and Gu 153)     

Effect of starvation upon insulin secretion in the rabbit

Summary Plasma insulin and blood glucose levels of normal and fasting rabbits have been studied. The mean plasma insulin of pre-starvation controls was 24 µU/ml; blood glucose was 107 mg/100 ml. After starvation, the insulin levels in the blood decreased to 8 µU/ml and glucose concentration to a mean level of 76 mg/100 ml. The fine structure of - and -cells was studied in fasted animals. Most of the -cells were filled with granules of the pale type and some of these secretory granules were adjacent to the plasmatic membrane, which frequently showed projecting microvilli. Immunoassay figures for pancreatic insulin were obtained. There was a good correlation between the insulin assay results in pancreas on one hand, and light and electron microscopic -cells on the other, provided the assumption is true that pale granules contain immunologically active insulin. Most of the -cells were well granulated, but a few of these cells showed a marked increase in the lamellar ergastoplasm.This work has been supported by a grant from the Seguridad Social del Estado, Madrid.     

Obstructive jaundice alters LFA-1alpha expression in rat small intestine

Translocation of bacteria and endotoxtin has long been documented in obstructive jaundice, and altered intestinal barrier function is considered to be one of the important mechanisms for this phenomenon. The regulation of gastrointestinal mucosal response to injury is thus of important clinical as well as biological relevance. Integrins play a critical role in enterocyte migration, which is essential to mucosal healing. This study is designed to evaluate the integrins status in obstructive jaundice. Male Sprague-Dawley rats (N = 37) were randomized to three groups. Group 1 (N = 12) underwent common bile duct ligation (CBDL), group 2 (N = 12) underwent common bile duct ligation with oral glutamine administration (CBDL + G), and group 3 (N = 13) underwent a sham operation (sham control). After seven days, segments of proximal jejunum and distal ileum were harvested, and cell surface immunohistochemical expression of LFA-1 and VLA-6 were evaluated and recorded. The staining intensities were graded on a scale of 0–4. Comparisons among the three groups were performed. There was no significant difference in VLA-6 staining on small intestine among the three groups (P < 0.05). There was also no significant difference in LFA-1 staining the on jejunum between grouP1 (CBDL) and grouP3 (sham control) (P < 0.05). However, the LFA-1 staining on the ileum in grouP1 (CBDL) significantly decreased when compared with grouP3 (sham control) (P = 0.008). With oral glutamine administration (0.2 g/kg body weight, once daily), LFA-1 staining on the ileum was significantly restored in grouP2 (CBDL + G). In conclusion, obstructive jaundice for one week down-regulates LFA-1 expression on rat ileum. With oral glutamine administration, such down-regulation of LFA-1 expression on rat ileum can be restored. Such a phenomenon is intriguing and deserves further evaluation and elucidation.     

Significance of acid amyloglucosidase in sulphonylurea-induced insulin release

Summary The effect of exogenous acid amyloglucosidase on sulphonylurea-induced insulin release was investigated in mice and rats. 1. Pretreatment of mice with acid amyloglucosidase enhanced insulin release induced by the different sulphonylurea derivatives, carbutamide, tolbutamide, glibenclamide, and glibornuride. 2. A dose-response relationship between glibenclamide-induced insulin response and amyloglucosidase dosage covering a 64-fold concentration range was established in mice. 3. Pretreatment of the animals with other macromolecules of similar physiological or chemical properties to acid amyloglucosidase such as-amylase,-glucuronidase and albumin did not influence glibenlamide-induced insulin release. 4. The effect of acid amyloglucosidase pretreatment on insulin release induced by different agents known to affect the islet-cell adenylate cyclase-cyclic AMP system such as secretin, L-isopropylnoradrenaline (L-IPNA), arginine, glibenclamide and 3-isobutyl-1-methylxanthine (IBMX) was tested. It was observed that in animals pretreated with acid amyloglucosidase, insulin release was enhanced when stimulated by glibenclamide, a phosphodiesterase inhibitor, but it was similarly enhanced by arginine, a phosphodiesterase activator. Insulin release induced by secretin, L-IPNA, and IBMX was unaffected. 5. Acid amyloglucosidase pretreatment in rats enhanced plasma immunoreactive insulin levels following glibenclamide injection not only in the peripheral veins but also in the portal vein. 6. Mice fasted for 24 hrs displayed a markedly depressed insulin response to tolbutamide injection. Pretreatment of the fasted animals with acid amyloglucosidase could restore the tolbutamide-induced insulin release to the same level as that recorded in a group of freely fed mice. It is suggested that acid amyloglucosidase plays an important role in insulin secretion induced by sulphonylureas. Most evidence suggests that this effect is exerted within the B-cell although an additional effect on the liver cannot be ruled out.     

Effects of glucocorticoids and insulin on 3′,5′-AMP phosphodiesterase activity in adrenalectomized rats

Summary Glucocorticoids stimulate the rate of lipolysis which is reduced in adrenalectomized animals. This hormonal action is antagonized by insulin. The antilipolytic action of insulin appears to be mediated by a reduced intracellular concentration of 3,5-AMP. This reduction can partly be attributed to an insulin-induced acceleration of 3,5-AMP degradation. — It is shown that the stimulatory influence of glucocorticoids on lipolysis is due to a reduction of 3,5-AMP phosphodiesterase (PDE) activity, which is increased by adrenalectomy. PDE activity was also increased in liver, skeletal muscle and kidney of adrenalectomized rats; treatment with a glucoeorticoid prevented this increase.In vitro, PDE purified from beef heart was inhibited by glucocorticoids in high concentrations (K_i=1.1 · 10^–3 M for 6 -methylprednisolone hemisuccinate,K _i=1.6 · 10^–3 M for prednisolone succinate).In vivo, the glucocorticoid-induced decrease of PDE activity (with retarded onset as shown in liver), may essentially be attributed to a decreased enzyme synthesis. — Studies on the interaction of insulin and glucocorticoids on PDE activity were performed in the liver. In adrenalectomized, alloxan diabetic rats insulin stimulated PDE activity suppressed by treatment with a glucoeorticoid, unsuppressed PDE activity was not increased by insulin. In contrast, the action of glucocorticoids on PDE activity was independent of the presence or the effectiveness of insulin.

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Wirkungen von Olucocorticoiden und Insulin auf die 3,5-AMP-Phosphodiesterase-Aktivität bei adrenalektomierten Tieren

Zusammenfassung Die Lipolyse, die bei adrenalektomierten Tieren vermindert ist, wird durch Glucocorticoide verstärkt. Die gegenüber Glucocorticoiden antagonistische Wirkung von Insulin, das die Lipolyse vermindert, kann durch eine Abnahme der intracellulären 3,5-AMP-Konzentration erklärt werden. Diese ist teilweise auf einen beschleunigten Abbau des Nucleotids zurückzuführen. — Die Lipolysesteigerung durch Glucocorticoide ist durch eine Verminderung der 3,5-AMP-Phosphodiesterase (PDE)-Aktivität bedingt, die bei adrenalektomierten Ratten erhöht ist. Die PDE-Aktivität adrenalektomierter Tiere ist auch in Leber, Skeletmuskulatur und Niere erhöht, die Gabe eines Glucocorticoids verhindert diesen Anstieg. Glucocorticoide hemmen aus Rinderherz isolierte PDEin vitro, jedoch sind hohe Steroidkonzentrationen erforderlich (K _i=1.1 · 10^–3 M für 6 -Methylprednisolon-Hemisuceinat, (K _i=1,6 · 10^–3 M für Prednisolon-Succinat). Die einige Stunden nach Gabe eines Glucocorticoids einsetzende Abnahme der PDE-Aktivität kann im wesentlichen auf eine verminderte Enzymsynthese zurückgeführt werden. — Insulin steigert bei adrenalektomierten, alloxandiabetischen Ratten die PDE-Aktivität in der Leber nur, wenn die Tiere mit einem Glucocorticoid behandelt sind, nicht jedoch die erhöhte PDE-Aktivität bei Fehlen von Glucocorticoiden. Der Einfluß von Glucocorticoiden auf die PDE-Aktivität ist dagegen nicht an die Wirkung von Insulin gebunden.

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Effets des glucocorticoïdes et de l'insuline sur l'activité de la 35-AMP-phosphodiestérase chez des rats surrénalectomisés

Résumé Les glucocorticoïdes stimulent la lipolyse qui est réduite chez les animaux surrénalectomisés. Cette action hormonale est contrecarrée par l'insuline. L'action antilipolytique de l'insuline semble être due à une réduction de la concentration intracellulaire de 35-AMP. Cette réduction peut être attribuée en partie à une accélération due à l'insuline de la dégradation du 35-AMP. On a montré que l'influence stimulatrice des glucocorticoïdes sur la lipolyse est due à une réduction de l'activité de la 35-AMP-phosphodiesterase (PDE), qui est accrue par la surrénalectomie. L'activité de la phosphodiesterase est également augmentée dans le foie, le muscle strié et les reins des rats surrénalectomisés, le traitement par un glucocorticoïde prévient cette augmentation.In vitro, la phosphodiesterase purifiée du coeur de boeuf est inhibée par les glucocorticoïdes à fortes concentrations (K _i=1.1 · 10^–3 M pour l'hémisuccinate de 6 -méthylprednisolone, (K _i=1.6 · 10^–3 M pour le succinate de prednisolone).In vivo, la diminution provoquée par les glucocorticoïdes de l'activité de la phosphodiesterase qui se produit au bout de quelque temps, comme on l'a montré dans le foie, peut essentiellement être attribuée à une synthèse diminuée de l'enzyme. Des études sur l'interaction de l'insuline et des glucocorticoïdes sur l'activité de la phosphodiesterase ont été effectuées sur le foie. Chez les rats surrénalectomisés, rendus diabétiques par l'alloxane, l'insuline stimule l'activité de la phosphodiesterase qui a été supprimée par un traitement avec un glucocorticoïde, l'activité de la phosphodiesterase qui n'a pas été supprimée n'est pas augmentée par l'insuline. Par contre, l'action des glucocorticoïdes sur l'activité de la phosphodiesterase est indépendante de l'action de l'insuline.

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Non-Standard Abbreviations G 6 P Glucose-6-phosphate - FFA non-esterified, 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.     

The prognostic significance of cytological,histological and cytogenetic findings in refractory anaemia (RA) and RA with sideroblasts

Summary Two independent observers performed a double review of cytological and histological bone marrow material obtained at diagnosis and during follow up in 34 patients with the myelodysplastic syndrome (MDS), subtypes refractory anaemia (RA) and RA with ringed sideroblasts (RA-S) (26 and 8 patients, respectively). Average values were used for the analyses. Data obtained at diagnosis confirmed earlier observations that a worse prognosis was indicated by high blast cell counts (P<0.01), presence of blast foci and clonal cytogenetic abnormalities (P=0.08). Data obtained during follow up, in addition, showed that an increased probability of progression to FAB-subtype RA with an excess of blasts was related to both the occurrence of blast foci (P<0.05) and the occurrence of new or additional clonal abnormalities (karyotype shift) (P<0.01). The relationship between parameters investigated at diagnosis, during follow up, and in the pooled material, points to RA-S being a separate entity having a better prognosis than RA, and further substantiates an earlier observed relationship between blast cell accumulation and the frequency of cytogenetically abnormal metaphases.This work was supported by Grant no. 003/83 from The Danish Cancer Society     

Exercise-induced proteinuria in children and adolescents with Type 1 (insulin dependent) diabetes

Summary The urinary excretion of albumin and -₂microglubulin was measured by radioimmunoassay in 64 children and adolescents with Type 1 (insulin dependent) diabetes and in 68 non-diabetic subjects aged from 9 to 19 years. At rest the albumin excretion of the diabetic subjects did not differ from that of the non-diabetic children and adolescents but during exercise the albumin excretion was significantly higher in children and adolescents with Type 1 diabetes (p<0.02). The excretion rate of ₂-microglobulin in diabetic subjects did not differ from that of the healthy subjects. Both at rest and during exercise the albumin excretion rate was highest in those diabetics with poorest metabolic control of their disease.     

Direct characterization ofΒ-adrenoceptors in membranes of immature red blood cells from rats

Summary By means of the radioactive antagonist ligand (³H) (–) dihydroalprenolol (DHAP) specific binding sites were identified in membrane preparations from red blood cells from rats. These specific sites were characterized as-adrenoceptors because of the following reasons: Specific binding of DHAP (in contrast to unspecific binding) was dependent on temparature and time of incubation. Furthermore, specific binding of DHAP showed saturability, temperature-dependent reversibility and high affinity (K_D-value of DHAP = 6.51 nM). Specific binding of DHAP was competitively inhibited by-adrenergic antagonists (pindolol > alprenolol propranolol > practolol) and agonists (isoprenaline > adrenaline). The (–) enantiomers of pindolol and isoprenaline showed pronounced higher affinities for the receptor sites than the respective (+) enantiomers. The receptor density in the membrane preparations (pmoles/mg protein) was strongly dependent on the degree of reticulocytosis: The B_max-values increased more than 4 to 5 fold without alteration of the respective K_D-values when reticulocyte counts were enhanced from 3 to 80 % treatment of the animals with increasing doses of acetyl phenylhydrazine.Preliminary accounts were presented at the meeting of the Deutsche Gesellschaft für HÄmatologie [19]     

Effects of natural free radical scavengers on peripheral nerve and neurovascular function in diabetic rats

Summary Increased generation of reactive oxygen species, coupled with impaired endogenous scavenging mechanisms, plays a prominent role in the aetiology of neurovascular abnormalities in experimental diabetes mellitus. We examined the efficacy of the natural anti-oxidants vitamins C, E and -carotene in preventing nerve conduction and nutritive blood flow deficits in streptozotocin-diabetic rats. One month of diabetes caused a 19.1% reduction in sciatic motor conduction velocity (p<0.001). This was approximately prevented 80–90% by high-dose (1000 mg · kg^–1 · day^–1) vitamin E and -carotene treatments (p<0.001). Vitamin C had lesser effects; the maximum protection found for motor conduction velocity was 36% using a dose of 150 mg · kg^–1 · day^–1 (p<0.001). High dose (500 mg · kg^–1 · day^–1) vitamin C had a lesser effect on conduction than intermediate doses. Joint vitamin C and lower dose (500 mg · kg^–1 · day^–1) vitamin E treatment had a predominantly additive preventive effect against nerve dysfunction. Resistance to hypoxic conduction failure for sciatic nerve in vitro was markedly increased by diabetes and this remained relatively unaffected by treatment. Sciatic nutritive endoneurial blood flow, measured using microelectrode polarography and hydrogen clearance, was reduced 46.1% by 1 month of diabetes (p<0.001). This was prevented to the extent of 87%, 36% and 98% by vitamins E, C and -carotene, respectively (p<0.01). These data emphasize the role of oxidative stress in the development of early neurovascular changes in experimental diabetes and show that naturally available scavengers have a neuroprotective action.Abbreviations NCV Nerve conduction velocity - NO nitric oxide - ROS reactive oxygen species     

Overproduction of inhibitory hematopoietic cytokines by lipopolysaccharide-activated peripheral blood mononuclear cells in patients with aplastic anemia

The aim of this study was to measure the level of cytokines produced by peripheral blood mononuclear cells (PBMNC) in patients with aplastic anemia (AA) and to determine their effect on the clonal growth of normal bone marrow (BM) cells. Twenty-one patients with AA and 11 normal controls were enrolled in this study. Medium conditioned by PBMNC of AA patients in the presence of lipopolysaccharide (LPS) was found to be suppressive to the colony growth of normal BM cells. Thus, we further determined the presence in the PBMNC-conditioned medium (CM) of both inhibitory cytokines: macrophage inflammatory protein-1 (MIP-1), tumor necrosis factor- (TNF-), transforming growth factor-2 (TGF-2), and interferon- (IFN-), and stimulatory cytokines: interleukin-3 (IL-3) and stem cell factor (SCF). Spontaneous production of MlP-1 was higher in the AA patients than the normal controls (1887±174 pg/ml vs 1643±93 pg/ml), but the difference was not significant. After LPS stimulation, the production of MIP-1 was markedly increased in the AA patients, and its level was significantly higher than that of the normal controls (2360±149 pg/ml vs 1517±92 pg/ml, p=0.0022). The level of TNF was also higher in the AA patients. However, IFN-, TGF-2, SCF, and IL-3 were not detectable in the PBMNC-CM of either AA patients or normals. The myelopoietic suppressing effect of AA-PBMNC-CM from each AA patient was significantly blocked by pretreatment with anti-TNF-, resulting in a colony-forming enhancement of 174%±12%. A similar effect was noted in six of 11 AA patients by pretreatment with anti-MIP-1. We conclude that TNF and MIP-1 can be overproduced by the PBMNC of some AA patients, which may play a role in the progression of AA.     

Esophagoprotective Potential of Cisapride (An Additional Benefit for Gastroesophageal Reflux Disease)

Cisapride is a novel prokinetic agent thatreleases acetylcholine at the level of the myentericplexus. Acetylcholine also plays a role in the secretoryfunction of salivary glands evoked by intraesophagal mechanical and chemical stimulation, mediatedthrough the esophagosalivary reflex. The impact,however, of cisapride on salivary protective componentsmediated by esophagosalivary reflex remains unknown. Therefore, we have studied salivary pH,bicarbonate, nonbicarbonate, glycoconjugate, protein,EGF, TGF-, and PGE₂ before and afterthe administration of cisapride. The study was conductedin 20 asymptomatic volunteers (9 women and 11 men, mean age 36,range 26-52). Salivary secretions were collected underbasal conditions and during masticatory, mechanical, andchemical stimulation before and after four days of cisapride administration (10 or 20 mg fourtimes a day). Cisapride administration resulted in a 45%increase in salivary volume during the basal condition(P < 0.01), a 32% increase during mastication (P < 0.05), a 53% increase during mechanical(P < 0.05), and a 51% increase during chemical (P< 0.01) stimulation. Cisapride administrationresulted also in a significant increase in salivaryprotein output (P < 0.05), salivary bicarbonate (P <0.05), and nonbicarbonate buffers (P < 0.05), andsalivary EGF (P < 0.05). Salivary glycoconjugatesignificantly increased only during mechanicalstimulation with the catheter and at the end of the esophageal perfusionprocedure (P < 0.05). Although a similar trend wasalso recorded during the analysis of salivaryPGE₂, this difference did not reachstatistical significance. Salivary pH and TGF- before and after cisaprideadministration remained unchanged. The stimulatoryimpact of cisapride on salivary volume and inorganic(bicarbonate and nonbicarbonate buffers) and organic(protein, glycoconjugate, and EGF) protective componentswould benefit patients with GERD and would also bepotential therapy for xerostomia.