Treatment of chronic hepatitis C with high-dose interferon α-2b

A comparative study of three different high-dose regimens of interferon--2b (IFN) was conducted in patients with chronic hepatitis C to determine which was better at obtaining a sustained remission. A total of 126 patients were assigned randomly to one of three groups: group A was given 10 million international units (MIU) of IFN six times a week for eight weeks; group B was given 10 MIU IFN six times a week for four weeks followed by three times a week for an additional eight weeks; group C was given 10 MIU IFN six times a week for two weeks followed by three times a week for 12 weeks. The total dose administered to each group was 480 MIU/patient. Only the dosing schedule varied among the three groups. Among 98 efficacy-evaluable patients, a sustained alanine aminotransferase (ALT) response, defined as persistent normalization of the ALT for greater than six months after the termination of treatment, was achieved in 21.2% (7/33) of group A, 42.3% (11/26) of group B, and 54.5% (18/33) of group C patients. Similarly, a sustained loss of measurable serum hepatitis C virus RNA was observed in 28.6% (8/28) of group A, 40.9% (9/22) of group B, and 48.3% (14/29) of group C patients. Based upon these data, it can be concluded that 10 MIU of IFN administered six days a week for two weeks followed by three times a week for an additional 12 weeks produces the highest rate of both biochemical and virological responses to IFN therapy in patients with chronic HCV.     

Biochemical mechanisms on species differences in gastric carcinogenesis

Summary The biochemical denitrosation of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) in tissues from four strains of rat, inbred Buffalo, Lewis, B-N, and the random-bred Sprague-Dawley, with different sensitivities to MNNG-induced gastric carcinomas was investigated as a possible explanation for the species/strain differences in MNNG-induced carcinogenesis. An analytical HPLC method was developed to assay denitrosation of MNNG to N-methyl-N-nitroguanidine (MNG) by cytosolic, microsomal, mitochondrial, and nuclear cell fractions. All the activity was contained in the microsomal and cytosolic fractions, with the major portion occurring in the cytosol. The activity in both fractions was NADPH-dependent, but denitrosation was not reduced by inhibitors of the cytochrome P-450 system. Denitrosation of MNNG post-mitochondrial supernatant (S9) fractions from liver, glandular stomach mucosa, and duodenal mucosa of the four rat strains was determined. In all strains, denitrosation activities were highest in liver. Comparisons between the three strains most sensitive to MNNG-induced gastric carcinogenesis indicated no large differences for any tissue. However, Buffalo, the most resistant strain, did have a higher level of denitrosating activity in all three tissues, which is consistent with the hypothesis that higher levels of detoxifying enzymes may lead to a decreased incidence of tumors. On the other hand, denitrosation accounts for less than 3% of the MNNG that disappears during the incubation perod so that the relevance of denitrosation as a mechanism in strain-specific sensitivity to MNNG-induced gastric carcinoma requires additional studies.Postdoctorate Fellow, American Health FoundationDedicated to Professor Hermann Druckrey, on the occasion of his 80th birthdaySupported by Public Health Service grant CA-30658 from the National Cancer InstitutePostdoctorate Fellow, American Health Foundation     

Decreased cyclic AMP and Insulin responses to glucose in pancreatic islets of diabetic chinese hamsters

Summary The dose as well as the time kinetics of insulin and adenosine-3,5-monophosphate (cyclic AMP) responses to glucose were compared in pancreatic islets isolated from normal and diabetic Chinese hamsters. The insulin content in diabetic islets was about one-half that in normal islets. Insulin release in diabetic islets incubated for 10 min with glucose 60–1000 mg/l00 ml was from one-third to one-half that in normal islets. Glucose 1000 mg/l00 ml stimulated three-fold increases in insulin release without increasing the accumulation of [³H] cyclic AMP in either normal or diabetic islets prelabelled with [³H] adenine. However, in the presence of 1.0 mM of the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX), glucose 150 mg/l00 ml elicited significant increases of insulin release (+ 134%) and [³H] cyclic AMP accumulation in islets (+ 44%) and incubation medium (+ 48%) of islets of normal but not diabetic hamsters. Also, in perifusion experiments with 0.1 mM IBMX, glucose 500 mg/l00 ml produced threefold greater increases in insulin release and two-fold greater increases in efflux of cyclic AMP in normal than diabetic islets. By contrast with the lesser effects of glucose in diabetic islets, 1.0 mM IBMX increased islet and medium cyclic AMP, as well as insulin release, similarly in normal and diabetic islets. It is suggested that the impairment of glucose induced insulin release in islets of the diabetic Chinese hamster may be due to a defective interaction of glucose with the adenylate cyclase-cyclic AMP system in the pancreatic B cell.This work was presented in part at a meeting of the European Association for the Study of Diabetes, Sept. 1975, Munich, Germanyon leave from the Department of Endocrinology, Karolinska Hospital, Stockholm     

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.

     

Sensitivity of CFU-GM from normal human bone marrow and leukaemic clonogenic cells (CFU-L) from blood of patients with myelogenous leukaemia to 3′-deoxy-3′-fluorothymidine in comparison to 3′-azido-3′-deoxythymidine

Summary 3-Deoxy-3-fluorothymidine (FT), a thymidine analogue highly effective against HIV 1 in vitro was investigated as to its in vitro effect on normal human bone marrow CFU-GM (agar colony assay) and on human peripheral myeloid leukaemic clonogenic cells (CFU-L, colony assay in methylcellulose). For comparison, 3-azido-3-deoxythymidine (AZT), structurally related and used in AIDS treatment, was included in the study. Both compounds inhibit the formation of clusters and colonies from bone marrow stem cells with an [IC]₅₀ between 10^–6 and 10^–5M. In concentrations only 5–10 times lower than the [IC]₅₀, FT begins to stimulate cluster and colony formation. AZT and FT also inhibit the formation of clusters and colonies from CFU-L. Compared to CFU-GM, CFU-L were more sensitive to FT, and a stimulation was not seen. It is concluded that similar side effects on bone marrow could be expected for possible use of FT against AIDS as have been found for AZT and that both compounds are potential candidates for antileukaemic drugs.     

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.     

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.     

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 Obesity on Pharmacokinetics and Biologic Effect of Interferon-alpha in Hepatitis C

To examine potential adverse effects of obesityin reducing the response to interferon-alpha (IFN-alpha)in chronic hepatitis C (HCV), IFN-alpha and HCV RNAlevels in serum and the 2,5-oligoadenylatesynthetase (2-5 OAS) levels in peripheral bloodmononuclear cells (PBMC) were compared between six obeseand five nonobese patients before and after a single, 10mIU dose of IFN-alpha_2b. There were nodifferences in the mean histologic activity index between thetwo groups. The maximal IFN concentration and the areaunder the serum IFN concentration-time curve were higherin nonobese patients. These two parameters were inversely correlated with body weight andbody surface area. No differences were found in the meanreduction in HCV RNA levels between the two groupsfollowing IFN-alpha. The maximal 2-5 OAS level after treatment divided by the pretreatment 2-5OAS level (2-5 OAS response ratio) was greater in thenonobese patients, suggesting stronger biologic responseupon exposure to exogenous IFN-alpha in nonobese patients.     

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)     

Autoradiographic observations on the distribution and metabolism of N′-/14C/nitrosonornicotine in mice

Summary The fate of the weak base N-nitrosonornicotine (2-¹⁴C-labeled) has been studied in mice. Whole-body autoradiography showed that the radioactivity was rapidly distributed throughout the body, which probably reflects an ability of the non-protonated compound to freely pass biological membranes and distribute evenly in the intra- and extracellular tissue water. Metabolites which were firmly bound to tissue macromolecules — retained throughout the observational period (24 h) — were present in the tracheobronchial and nasal mucosa, the liver, the submaxillary and sublingual salivary glands and the esophagus. Radioactivity in the lacrimal gland, the gastrointestinal contents, the urinary bladder, and the gallbladder seems to be related to excretion of the substance and/or its metabolites. A binding to the melanin in the eye and hair was observed in vivo and in vitro. Experiments with mice pretreated with diethyldithiocarbamate and nialamide showed that these substances partially inhibited the metabolism of N-/¹⁴C/nitrosonornicotine. CO₂ was not recovered in the breath during the 4 h following the administration of N-/¹⁴C/nitrosonornicotine.Sponsored by the Swedish Tobacco Company (Grant No. 7820)     

Tierexperimentelle Untersuchungen zur Morphogenese Nitrosamin-induzierter colo-rectaler Tumoren

Zusammenfassung In den vorliegenden Untersuchungen an insgesamt 154 männlichen Wistarratten, einschließlich der Kontrolltiere, wurden teilweise doppelläufige Colostomien zur Ausschaltung der Kotpassage angelegt. Diesen Ap-Tieren wurden ebenso wie kontinenten Tieren 2mal wöchentlich 2 mg N-Methyl-N-nitroso-N-nitroguanidin (MNNG) rectal instilliert. Die Applikation erfolgte über einen Zeitraum von 210 Tagen. Dabei entwickelten sich bei den Ap-Tieren im ausgeschalteten Colorectum Carcinome in 6,5% und Polypen in 19,4%, während bei den kontinenten Tieren Carcinome in immerhin 26,3% und Polypen in 57,9% entstanden. Die Ausschaltung der Kotpassage führt mithin zu einer signifikanten Minderung der MNNG induzierbaren Tumorzahl.MNNG induzierte Carcinome entwickeln sich mehrheitlich in vorbestehenden adenomatösen Polypen; sog. de novo-Carcinome sind extrem selten.

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Nitrosamin induced neoplasms of the colon and rectum. Investigations on the morphogenesis in rats

Summary The morphogenesis of neoplasms (carcinomas and praecancerous polypoid lesions) induced by N-methyl-N-nitroso-N-nitroguanidine (MNNG) was studied on 154 male Wistar rats (including controls), from which a group received a colostomy, Operated and non-operated rats were treated by intrarectal instillations of 2 mg per kg body weight MNNG twice a week during a period of 210 days.The group of non-operated rats developed carcinomas and praecancerous polypoid lesions in a rate of 26.3% respectively of 57.9%. Whereas in the group with colostomy the rate of carcinomas was only 6.5% and of praecancerous polypoid lesions only 19.4%.Conclusions Eliminating the exposure to faeces through colostomy reduces significantly the rate of MNNG induced neoplasms. The vast majority of MNNG induced colo-rectal carcinomas arose from adenomatous polypoid lesions; so called de novo carcinomas were extremely rare.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft     

Short-term inhibition of peroxisome proliferator-activated receptor-γ coactivator-1α expression reverses diet-induced diabetes mellitus and hepatic steatosis in mice

Aims/hypothesis The coactivator of nuclear receptors, peroxisome proliferator-activated receptor- coactivator-1 (PGC-1) has been implicated in a series of events that contribute to the control of glucose metabolism. We have recently reported the use of a PGC-1 antisense oligonucleotide (PGC-1AS) that inhibits up to 60% of PGC-1 expression in pancreatic islets, leading to increased insulin secretion. This oligonucleotide was used in this study to try to ameliorate diet-induced type 2 diabetes in a genetically predisposed mouse strain (Swiss mice).Materials and methods Glucose and insulin tolerance tests, euglycaemic–hyperinsulinaemic clamp, immunoprecipitation assays, immunoblotting assays and immunohistochemistry were used in this investigation.Results Swiss mice became obese and overtly diabetic after 8 weeks of feeding with chow containing 24% saturated fat. One daily dose (1.0 nmol) of PGC-1AS significantly reduced glucose and increased insulin blood levels without affecting food intake and body weight. These effects were accompanied by a reduced area under the glucose curve during an intraperitoneal glucose tolerance test, an increased constant of glucose decay (K_itt) during an insulin tolerance test, and an increased glucose consumption rate during a euglycaemic–hyperinsulinaemic clamp. Moreover, mice treated with PGC-1AS presented an outstanding reduction of macroscopic and microscopic features of hepatic steatosis. These effects were accompanied by reduced expression or function of a series of proteins involved in lipogenesis.Conclusions/interpretation PGC-1 is an attractive target for pharmacological therapeutics in type 2 diabetes mellitus and diet-induced hepatic steatosis.     

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)     

Tumor-promoting activity and cytotoxicity of 3,4,3′,4′-tetrachlorobiphenyl on N-nitrosomorpholine-induced murine liver foci

Summary Effects of 3,4,3,4-tetrachlorobiphenyl (TCB) on glucose-6-phosphatase (G6Pase)-altered hepatic foci of N-nitrosomorpholine (NNM)-treated B6C3F1 mice were investigated. TCB was chosen as a selective 3-methylcholanthrene-type inducer and tumor promoter. To initiate hepatocarcinogenesis, mice were treated with NNM (160 mg/l, in drinking water for 7 weeks), as in previous studies with the rat model. After a treatment-free interval of 22 weeks, TCB was administered (5×50 mg/kg, every 3 days), and liver foci were analysed 10 weeks after the start of TCB treatment. Unexpectedly, the number of G6Pase-negative and-positive foci per liver was markedly diminished following TCB treatment (to 32% and 57%, respectively). On the other hand, the mean volume of the remaining G6Pase-altered foci was enhanced, owing to an increase in the percentage of foci of large size (>0.5mm²). Throughout the experimental period of 39 weeks prolonged liver injury due to NNM and TCB treatment was demonstrated by histology and by elevated serum levels of glutamate-oxaloacetate transaminase. The results suggest that (in contrast to the rat system) TCB exhibited opposing effects on liver foci in the mouse model: (a) moderate tumor-promoting effects and (b) cytotoxic effects in NNM-injured liver, leading to decreased numbers of liver foci.Abbreviations used G6Pase glucose-6-phosphatase - NNM N-nitrosomorpholine - TCB 3,4,3,4-tetrachlorobiphenyl     

Inhibition by 16,16-Dimethyl Prostaglandin E2 of Tumor Necrosis Factor-α and Interleukin-1β Production and Messenger RNA Expression in Human Monocytes Stimulated by Helicobacter pylori

We investigated the effects of 16,16-dimethylprostaglandin E₂ on the production of tumornecrosis factor- and interleukin-1 in humanmonocytes stimulated with Helicobacter pylori. Monocytes isolated from human peripheral blood wereincubated for 24 hr with the extract of H. pyloridiluted 1:100 to 1:100,000 by volume, a combination ofthe extract and 16,16-dimethyl prostaglandinE₂, or a vehicle alone. The extract stimulated theproduction of tumor necrosis factor- andinterleukin-1 and the expression of theirmessenger RNA in a dose-dependent manner. 16,16-Dimethylprostaglandin E₂ inhibited the production of thesecytokines and their messenger RNA in the presence of H.pylori at doses higher than 10^-6 M,predominantly with tumor necrosis factor-. These data suggest that antiinflammatory effects ofprostaglandins on gastric mucosa are in part related totheir effects on inhibition of production ofproinflammatory cytokines by monocytes.     

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%).     

Acute hematologic effects of interferon alpha,interferon gamma,tumor necrosis factor alpha and Interleukin 2

Summary This study was designed to investigate acute effects of various doses of the cytokines IFN-alpha, IFN-gamma Interleukin 2 and tumor necrosis factor alpha on white blood cell differential counts. Before initiation of phase II trials, a dose-determination phase was performed, where three different dose levels of each cytokine were applied as a single dose. White blood cell differential counts were assessed immediately before and 2, 12, 24, 48 and 168 h after injection. Patients enrolled suffered from metastatic cancer or chronic active hepatitis. In addition, IFN-alpha was administered to five healthy volunteers. Results indicate that cytokines cause rapid and transient changes in the numbers of leukocyte subsets. Hematologic changes were cell-type- and cytokine-specific: transient lymphopenia was observed after administration of all four cytokines, reaching a nadir 12 to 24 h after subcutaneous injection. Administration of TNF-alpha and IFN-gamma also caused transient monocytopenia. Neutrophilia developed after administration of Interleukin 2, IFN-alpha and TNF-alpha. We conclude that cytokines play a key role in the regulation of peripheral blood cell traffic by their capacity to influence homing patterns of peripheral blood leukocytes.     

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.