Differences in the regional distribution and response to ischaemia of adenosine-regulating enzymes in the heart

Summary The activities of the adenosine-generating enzyme 5-nucleotidase and the adenosine-degrading enzyme adenosine deaminase were determined for four regions of rat hearts prior to and following 10–60 min of ischaemia. Whereas adenosine deaminase was uniformly active throughout the heart, 5-nucleotidase was twice as active in atrial than in ventricular myocardium, and more active in the right than in the left ventricles in normoxic tissues. In isolated heart preparations normoxic perfusion decreased adenosine deaminase and increased 5-nucleotidase activity compared to levelsin vivo. Global ischaemia for 10 min elevated adenosine deaminase activity but had no effect on 5-nucleotidase activity. However, 30 min of ischaemia decreased 5-nucleotidase activity by 50% in all regions of the heart. These changed levels were not altered by 10 min of reperfusion. The fall in 5-nucleotidase activity with ischaemia occurred only in the 90% of this enzyme which is membrane-bound. The reasons for the marked differences in distribution and responses to ischaemia of these two enzymes have yet to be elucidated but metabolic inhibitors seem unlikely to be involved.     

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)     

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.     

Autonomic responses and neurohumoral control in the human early antenatal heart

Summary Previous sporadic findings and the results of recent, more systematic studies now permit us to make an attempt to outline the contribution of the sympathetic and parasympathetic system to the control of the human early antenatal cardiac function. In the developing heart of man, only acetylcholine and catecholamines have so far been proven to act as true autonomic transmitters. Muscariniccholinergic responses to acetylcholine and related agents can be detected from the 4th postconception week onwards, i.e. soon after the initiation of the first heartbeats. The same applies to the -adrenergic responsiveness to noradrenaline, adrenaline and other adrenergic stimulants in a somewhat later period, commencing at week 5 after conception. The maximum cardiac response to all these agonists becomes stronger as development continues. — Evidence is accumulating to suggest that prostaglandins and triiodothyronine might modulate the regulatory function of autonomic transmitters in the human early antenatal heart.Morphological and functional establishment of the autonomic innervation occurs in the human heart well after the appearance of the reactivity to autonomic transmitters. Under in vitro conditions, muscarinic-cholinergic neuro-effector transmission can be demonstrated in 10–12-week-old hearts, and cardiac -adrenergic transmission can first be detected in weeks 13–14. From these observations and from the appearance of the in utero fetal tachycardiac response to atropine in weeks 15–17 and the bradycardiac response to -blockers in weeks 23–28, it seems that the parasympathetic-cholinergic control of the developing human heart becomes functional and can play a role in the overall regulation of the antenatal cardiac function carlier than the sympathetic-adrenergic neural control. In the period before the onset of sympathetic neural control, the adrenergic regulation of the antenatal heart is achieved predominantly through the extra-adrenal (mainly the para-aortic) chromaffin tissues, whereas the co-operative function of the adrenal medulla becomes effective later in fetal life.     

Effect of chronic exercise on glucose uptake and activities of glycolytic enzymes measured regionally in rat heart

Summary Regional glucose uptake in perfused hearts, and the activities of several glycolytic enzymes contributing to the glucose metabolism in perfused and nonperfused hearts were studied in male and female rats after 8–9 weeks of swimming training. The left ventricular glucose uptake showed a transmural gradient in the sedentary animals, the subendocardial uptake being 30% and 12% higher than that of the subepicardial layer in the males and females, respectively. Swimming exercise abolished the left ventricular glucose uptake gradient in male rats, and in female rats an opposite gradient was found, the subepicardial uptake being 23% higher than the subendocardial uptake. The activities of phosphofructokinase and 3-phosphoglyceraldehyde dehydrogenase also showed transmural gradients in the left ventricles. Training did not abolish these gradients. Training-induced changes in the activities of phosphofructokinase, 3-phosphoglyceraldehyde dehydrogenase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, citrate synthase, and malate dehydrogenase were found in certain sites of the myocardium. Perfusion of isolated hearts for 50 min with insulin-containing Krebs-Ringer buffer especially affected the activities of phosphofructokinase, lactate dehydrogenase, and citrate synthase, increasing these activities in the left ventricles and decreasing them in the atria. These results indicate that there are regional differences between male and female rats in the cardiac glucose uptake rate after swimming training.Supported by a grant from the Research Council for Physical Education and Sport, Ministry of Education, Finland.     

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     

Lack of correlation between two markers of lymphocyte differentiation: 5′ nucleotidase activity and T lymphocyte colony formation

Summary Ecto 5 nucleotidase (5 NT) activity and T lymphocyte colony formation (TLCF) are both reputed to be markers for lymphocyte maturation. In order to determine whether these two expressions of lymphocyte activity are related, we compared 5 NT activity with the TLC forming capacity of mononuclear cells from three study groups: normal adults, cord blood, and patients with immunodeficiencies. Despite individual examples of correlation between these two measurements, there was poor overall correlation in any of the groups studied. Although both measurements may reflect maturation of certain cellular activities, these are unlikely to be related.     

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.     

Controversies in preconditioning

Summary Preconditioning is an effective means of protecting the heart against prolonged ischemia by pretreating it with a minor insult, and the present paper reviews various controversies in this highly active field of research. In many models, adenosine plays a role by triggering the activation of protein kinase C. It may work in conjunction with other agents, such as bradykinin, but the putative role of noradrenaline is uncertain. Regulation of the enzyme producing adenosine (i.e., 5-nucleotidase) has been reported during preconditioning but, because its activity does not seem to be associated with infarct size, it is unlikely that the hydrolase plays a pivotal role. Controversial data have been published on the involvement of mitochondrial ATPase, which may be ascribed to the poor time resolution of the experiments described; however, we do not believe that either acidosis or tissue ATP are important factors in triggering preconditioning. The role of glycolysis in the preconditioning effect remains to be firmly established; opposite mechanisms are activated in low-flow and stop-flow protocols. Although species differences regarding preconditioning exist, they seem to be more of a quantitative than a qualitative nature. The phenomenon could be clinically relevant because evidence is accumulating that preconditioning may take place during bypass surgery and coronary angioplasty if longer balloonocclusion times are used.     

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.     

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.     

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     

Effects of long-term monotherapy with metoprolol CR/XL on the progression of left ventricular dysfunction and remodeling in dogs with chronic heart failure

We examined the effects of long-term monotherapy with the beta-blocker, metoprolol controlled release/extended release (CR/XL), on the progression of LV dysfunction as well as on global and cellular remodeling in dogs with heart failure (HF). Chronic HF was produced by intracoronary microembolizations that were discontinued when LV ejection fraction (EF) was between 30% and 40%. Dogs were randomized to 3 months oral monotherapy with metoprolol CR/XL (100 mg once daily, n = 7) or no therapy at all (control, n = 7). In control dogs, EF decreased from 38 ± 1% to 31 ± 2% (p = 0.002), and LV end-systolic volume (ESV) and LV end-diastolic volume (EDV) increased (37 ± 2 vs 45 ± 2 ml, p = 0.001; 59 ± 3 vs 65 ± 3 ml, p = 0.001; respectively) during the 3 month follow-up period. In dogs treated with metoprolol CR/XL, EF increased after 3 months from 36 ± 1% to 43 ± 1% (p = 0.001), and ESV decreased (42 ± 2 vs 38 ± 2 ml, p = 0.003), whereas EDV remained unchanged. Compared to controls, treatment with metoprolol CR/XL showed 46% reduction in replacement fibrosis, 54% reduction in interstitial fibrosis and 20% reduction in myocyte cross-sectional area, a measure of myocyte hypertrophy. These findings indicate that metoprolol CR/XL improves LV function and attenuates progressive global and cellular LV remodeling in dogs with HF. The benefits are fully attributable to -blockade alone as no other adjunctive therapy was used.     

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.     

Hyperkinetic contraction of a nonischemic segment of ischemic left ventricle in anesthetized dogs

Summary Regional myocardial function during acute coronary artery occlusion was studied with ultrasonic dimension gauges in 20 open-chest anesthetized dogs. Two pairs of ultrasonic crystals were implanted in the left ventricular free wall near the epicardium in an ischemic segment and in a control nonischemic segment, and the segment length (SL) and maximum velocity of systolic shortening (max dL/dt) were measured. In six dogs, the wall thickness (WT) was measured simultaneously in the same regions with sonomicrometry. Left ventricular pressure (LVP), aortic pressure (AoP), and plasma norepinephrine concentration in the coronary sinus (NE_CS) were also measured. The heart rate was kept constant (180 beats/min) with atrial pacing. The left anterior descending coronary artery was occluded at its distal portion without propranolol in 12 dogs (group 1) and 30 min after propranolol in eight dogs (group 2). In the ischemic region, coronary artery occlusion resulted in an increase in end-diastolic SL (50% at 3 min after occlusion in group 1,P<0.005), and a decrease in max dL/dt in systole (36% at 5 min after occlusion in group 1,P<0.02). In the nonischemic region, end-diastolic SL did not change significantly, but an increase in max dL/dt (29% at 10 min after occlusion in group 1,P<0.005) was observed in systole. Under propranolol (group 2), the results were similar to those of group 1. There were no significant changes in LVP, AoP, and NE_CS during occlusion. We conclude that: (1) SL and WT in the same region present a mirror image, suggesting that WT is a useful index for evaluating regional myocardial function; (2) after coronary artery occlusion, while the ischemic region showed hypokinesis, the nonischemic region presented significant hyperkinesis without an increase in preload (end-diastolic SL) or a decrease in ventricular afterload (AoP); and (3) since these results did not change significantly after propranolol and were not accompanied by an increase in NE_CS, the hyperkinesis in the nonischemic region does not seem to be related to-adrenergic receptors and is not due to the Frank-Starling mechanism.     

Cyclic nucleotide phosphodiesterases in the human lung

Although theophylline has been used in the treatment of lung diseases, particularly bronchial asthma, since the nineteenth century, the mechanisms underlying its effectiveness remained poorly understood until quite recently. The identification of cyclic nucleotide phosphodiesterase (PDE)— the enzyme responsible for breaking down cyclic AMP and cyclic GMP within cells—as a target for methylxanthines such as theophylline led to a research effort that has resulted in the characterization of multiple forms of the PDE enzyme and the development of selective inhibitors for some of these forms. Using these drugs, it has been possible to identify the PDE isoenzymes in a number of tissues and cells and to demonstrate the functional effects of the inhibition of different PDEs upon these tissues. Studies on the smooth muscle of human airways and pulmonary arteries have identified isoenzyme-selective PDE inhibitors that are effective broncho- and vasorelaxants in vitro, and it is hoped that these agents may be effective in relieving airway obstruction and pulmonary hypertension in patients. In addition, selective inhibitors of certain PDE isoenzymes suppress the pro-inflammatory functions of a range of immune cells, including the lung mast cell and the alveolar macrophage. Selective inhibitors of PDE isoenzymes are beginning to undergo clinical trials for the treatment of asthma. The advancing understanding of the PDE distribution in the lung and the ever more precise characterization of distinct enzyme proteins should allow the development of site-selective drugs for the treatment of lung diseases, while minimizing the systemic side effects associated with nonselective PDE inhibitors such as theophylline. Offprint requests to: K. F. Rabe     

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.     

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.     

Phase I study of pirarubicin

Summary A Phase I trial of pirarubicin (4-O-tetrahydropyranyl-doxorubicin) was undertaken to study its toxicity and to gain preliminary knowledge of its efficacy. The dose was escalated by increments of 10 from 30 to 70 mg/m². Out of 20 patients, 19 were evaluable for toxicity and response to treatment. Hematologic toxicity was dose limiting and dose related. Other adverse effects included nausea and vomiting, hair loss, and stomatitis. No acute cardiotoxicity was encountered. In 2 patients with metastatic breast cancer who had not been pretreated with cytostatic agents, a partial remission was achieved lasting for 5 months. In 6 patients, tumor parameters did not change for a median of 3 months, and 11 patients suffered progressive disease.     

Entwicklung neuer Antiöstrogene vom Typ des 3,3′-Dihydroxy-α,β-diäthylstilbens und ihre Prüfung am DMBA-induzierten,hormonabhängigen Mammacarcinom der SD-Ratte

Zusammenfassung Die Verlagerung der phenolischen OH-Gruppen des Diäthylstilböstrols in die 3,3-position (trans-3,3-Dihydroxy-,-diäthylstilben, Verb. Nr. III) führt unter Erhaltung der Rezeptoraffinität zu einer starken Abnhme der östrogenen Wirkung. III hemmt in vitro die östradiol-Rezeptor-Wechselbeziehung kompetitiv und antagonisiert in vivo bei der Maus die uterotrope Wirkung des Östrons. In Versuchen am DMBA-induzierten, hormonabhängigen Mammacarcinom der Ratte kommt es, unter III-Einwirkung dosisabhägig zu einer starken Abnahme von Tumorgröße und-zahl, die durch die antiöstrogenen Eigenschaften von III bedingt, ist. Der Austausch der ,-ständigen Äthylreste in III durch andere Alkylketten führt zu keiner weiteren, Steigerung der antiöstrogenen und tumorhemmenden, Wirkung.

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Abkürzungen trans-4,4-DES trans-4,4-Dihydroxy-,-diäthylstilben (Diäthylstilböstrol DAB 7) - I trans-3,3-Dihydroxy-,-dimethylstilben - II cis-3,3-Dihydroxy-,-diäthylstilben - III trans-3,3-Dihydroxy-,-diäthylstilben - IV trans-3,3-Dihydroxy-,-di-n-propylstilben - V trans-3,3-Dihydroxy-,-di-n-butylstilben - VI trans-2,2-Dihydroxy-,-diäthylstilben - DCC Dextran Coated, Charcoal - DMBA 7,12-Dimethylbenz-[a]-anthracen - TRIS Tris-(hydroxymethyl)-aminomethan - EDTA Äthylendiamintetraessigsäure - E2 Östradiol - ³H-E2 Östradiol [2,4,6,7-³H]; 90–115 Ci/mmol (New England Nuclear, Dreieichenhain/Frankfurt) - PPO 2,5-Diphenyloxazol - Dimethyl-POPOP p-Bis-2-(4-methyl-5-phenyl-oxazoyl)-benzol - K _d Dissoziationskonstante des Östradiol-Rezeptor-Komplexes - K _i Dissoziationskonstante des Inhibitor-Rezeptor-Komplexes - SDS Natriumdodecylsulfat - TCA Trichloressigsäure Der Deutschen Forschungsgemeinschaft, und dem Verband der Chemischen Industrie-Fonds der Chemischen Industrie — danken wir für die Förderung dieser UntersuchungenFrau G. Braun und Frau J. Garamvölgy danken wir für ihre wertvolle MitarbeitEin Teil der Untersuchungen wurde im Institut für Pharmazie, und Lebensmittelchemie der Universität München durchgeführtHerrn Prof. Dr. Heinrich Thies zum 75. Geburtstag gewidmet