Granulocyte colony-stimulating factor (G-CSF) as an adjunct to induction chemotherapy of adult acute lymphoblastic leukemia (ALL)

Summary Our purpose was to evaluate the ability of re-combinant human granulocyte colony-stimulating factor (r-metHuG-CSF) as an adjunct to induction chemo-therapy of acute lymphoblastic leukemia (ALL) to ameliorate chemotherapy-induced neutropenia and thus allow patients to receive full doses of chemotherapy on time. Sixteen consecutive patients with adult ALL (13 de novo, three relapsed) were treated with induction chemo-therapy according to the BMFT protocol and received in addition r-metHuG-CSF (200g/m²/day). Patients who were treated with the same induction chemotherapy but without G-CSF between 1982 and 1990 served as controls. Fifteen of the 16 patients achieved complete hematological remission. One patient died because of fungal septicemia. Compared with historical controls, G-CSF-treated patients had a significantly faster neutrophil recovery in phase I, resulting in neutrophil counts > 1000/l at day 17 vs day 26 (in median) in controls. In phase II, the onset of severe leukocytopenia (< 1500/l) was significantly (p = 0.01) delayed and the degree of leukocytopenia less pronounced (mean nadir 3300/l) in G-CSF-treated patients compared with controls (1880/l). The number of days of febrile neutropenia was not different in phase I. In phase II it was lower in study patients (0 vs 1.1 days), but the difference did not reach statistical significance (p = 0.09). Full doses of chemo-therapy could be given on time to 11/13 (85%) G-CSF pa-tients but to only 7/30 (23%) controls. These data indicate that (a) G-CSF can be given along with chemotherapy in induction treatment of ALL without compromising efficacy; (b) the duration of neutropenia in phase I is markedly shortened and the degree of leukocytopenia in phase II ameliorated; (c) these beneficial effects allow patients to receive full doses of chemotherapy on time.     

Efficacy and Tolerability of the Long-Acting Somatostatin Analog Lanreotide in Acromegaly. A 12-Month Multicenter Study of 58 Acromegalic Patients

Objective: To determine the effects of the new somatostatin analogue, lanreotide, in its prolonged released form (PR), in patients with acromegaly.Design: Prospective open multicenter non comparative study.Setting: Thirty-three university-affiliated medical centers.Patients: One hundred sixteen acromegalic patients with active disease, of whom 58 patients complied with the protocol and completed the 12-month period treatment.Intervention: Lanreotide PR treatment was started at a dose of 30 mg intramuscularly every 14 days. If integrated mean plasma GH levels were not below 5 g/L and/or IGF-I levels were not normalized after one month of treatment, injections were given every 10 days. The duration of the study was 12 months.Results: After one month of treatment mean plasma GH and IGF-I levels had fallen from 10.7 ± 11.1 g/L (mean ± SD; range, 2.6 – 74.8 g/L; median, 7 g/L) and 718 ± 270 g/L (range 338 – 1440 g/L; median, 645 g/L), respectively, to 7.8 ± 10.1 g/L and 575 ± 252 g/L, respectively. Thirty patients (22%) had plasma GH levels below 2.5 g/L, and 8 patients (16%) had age-adjusted normal plasma IGF-I levels. At the sixth month of treatment mean plasma GH levels of 2.5 g/L or less, and normal plasma IGF-I levels were observed in 33%, and 33% of patients, respectively. At the twelvth month of treatment, these percentages were 41%, and 41%, respectively. The interval between two injections was shortened (one injection every 10 days) in 8 of the 58 patients (13%) at the second month of treatment, and at the end of the study, 70% of patients required 3 injections per month. The most frequent adverse event elicited by enquiry was transient diarrhea (76% of patients), followed by abdominal pain (62%) and pain at the injection site (59%). Based on the analysis of a subgroup of 46 patients who had at least a measurement of fecal fat content after day 0 of the study, a non significant increase (from 4.2 ± 3.4 to 5.1 ± 4.3 g/24h, p = 0.3) in mean steatorrhea was observed during treatment. Before treatment, steatorrhea was present in 9 (19%) patients. During the study, 15 additional patients (32%) developed persistent steatorrhea, and there was a transient increase in fecal fat content above 6 g/24 h in another 11 patients. After exclusion of the 7 patients (12%) with gallstones at enrolment, new gallstones were diagnosed in 6 out of 50 patients (12%) during the study.Conclusion: Two or three monthly injections of lanreotide PR decreased GH concentration to less than 2.5 g/L and normalized IGF-I levels in 41% of patients treated during 12 months. The good tolerability of this treatment, and the reduction in the frequency of injections, plus the sustained drug serum concentrations, confirm the usefulness of this new somatostatin analog formulation.     

Modulation of pacemaker activity in sheep cardiac Purkinje fibers by stimulation of β-adrenoceptor subtypes

The electrophysiological effects mediated by ₁- and ₂- in spontaneously active sheep cardiac Purkinje fibers were investigated using the non-selective agonist (–)-isoproterenol (IPN) and the selective agonists (–)-noradrenaline (₁) and procaterol (₂) in the absence and presence of the selective antagonists bisoprolol (₁) and ICI 118,551 (₂).IPN (0.01 mol/l) increased the spontaneous rate by 54% and the slope of diastolic depolarization by 68% of the respective control values. Further, IPN increased the action potential duration at –20 mV (APD –20 mV) from 96 to 154 ms, reduced the APD –70 mV by 17% and the duration of the diastole by 39% and slightly hyperpolarized the maximum diastolic potential. These effects were partially inhibited by ICI 118,551 (0.03 mol/l), diminished by bisoprolol (0.1 mol/l) and almost completely blocked by the combination of both antagonists. Concentration response curves of IPN were influenced by the selective antagonists as follows: ICI 118,551 (0.03 mol/l) shifted the curves to the right by 0.2–0.4 log units and increased the slope factor. Bisoprolol (0.1 mol/l) induced a greater shift to the right by 1.1–1.5 log units. Combination of bisoprolol with ICI 118,551 shifted the curves to the right by 1.5–1.7 log units.Noradrenaline (0.3 mol/l) elicited similar actions as IPN. Bisoprolol (0.1 mol/l) shifted the concentration response curves of noradrenaline to the right by 1.1–1.9 log units. Actions of procaterol (0.1 mol/l) were weak, attained only 15–35% of the maximal effects of IPN and could be blocked by ICI 118,551 (0.03 mol/l).These results show that the increase of pacemaker activity induced by catecholamines in sheep cardiac Purkinje fibers is predominantly mediated by stimulation of ₁. However, contribution of ₂ mediated effects could be demonstrated.Supported by Ministerium für Wissenschaft und Forschung, Nordrhein-Westfalen, Projekt-Nr, 40008786.     

Inhibition of biliary phospholipid and cholesterol secretion by cefoperazone

The effect of cefoperazone, a third-generation cephalosporin, on biliary lipid secretion in rats was examined. Rats were anesthetized with ether and the mid-lumbar vein and common bile duct cannulated. Bile acid secretion was maintained by intravenous taurocholic acid infusion (28 mol/hr). A 1-hr control period was followed by intravenous cefoperazone infusion at either submaximal (20 mol/hr), or supramaximal (60 mol/hr) concentrations. At the cefoperazone infusion rate of 20 mol/hr (biliary secretion of 7.1±1.6 mol/hr) phospholipid secretion fell 19% and cholesterol secretion fell 31%; at a cefoperazone infusion rate of 60 mol/hr (biliary secretion rate of 27.1±5.1 mol/hr) phospholipid and cholesterol secretion were further reduced 40% and 56%, respectively, of controls. All changes were significant (P<0.01). Inhibition of both cholesterol and phospholipid secretion paralleled each other, was dose-dependent, and reversible. Cefoperazone's inhibitory action was abolished at a bile acid infusion rate of 108 mol/hr. Cefoperazone was not found to be associated with bile acid micelles or mixed micelles as determined by ultracentrifugation and gel filtration. Thus, the effect of cefoperazone on biliary lipid secretion is not due to the impairment of mixed micelle formation in the canalicular lumen but rather its inhibitory effect appears to be due to a presecretory event.     

Granulocyte colony-stimulating factor (rh G-CSF) as an adjunct to interferon alpha therapy of neutropenic patients with hairy cell leukemia

Summary Six patients with hairy cell leukemia (HCL) and neutropenia (median neutrophil count 563/l, range 30–1200) were treated with recombinant human granulocyte colony-stimulating factor (G-CSF) at a dose of 5g/kg by daily subcutaneous injection as an adjunct to interferon-alpha (IFN-a) therapy, in order to ameliorate neutropenia. Five of six patients responded to G-CSF with normalization of neutrophil counts (>1800/l) within 2–11 days and a median neutrophil count of 5211/l (range 4312–10160) at the end of G-CSF therapy. In three of these patients, infections resolved when neutropoiesis recovered. In one patient with very severe neutropenia (30/l), in whom myeloid progenitors were not detectable, G-CSF therapy failed to restore granulopoiesis. Cessation or interruption of G-CSF after 2–5 weeks of therapy resulted in a rapid decline of neutrophil counts to lower or subnormal levels (median value 1478/l, range 770–2739) within 1 week, suggesting that the improvement of granulopoiesis was dependent on G-CSF and not due to IFN-a therapy. G-CSF may be a useful adjunct to IFN-a therapy in patients with HCL in order to manage or prevent neutropenic complications in the early phase of treatment.     

Insulino-sécrétion étudiée sur le pancréas isolé et perfusé du rat II. Action des catécholamines et des substances bloquant les récepteurs adrénergiques

Résumé Nos expériences réalisées sur le pancréas isolé et perfusé du rat, dont la sécrétion est légèrement stimulée par le glucose à la concentration de 1.5 g/l, nous ont permis de constater les faits suivants: — 1. La L-adrénaline et la L-noradrénaline à faibles concentrations (0.0055 M/l et 0.011 M/l) provoquent une diminution importante de la sécrétion d'insuline. La L-adrénaline a une action plus fortement inhibitrice que la L-noradrénaline. La L-isoprénaline, à la concentration de 0.05 M/l stimule d'abord 'insulino-sécrétion puis provoque une diminution progressive. — 2. L'inhibition provoquée par la L-adrénaline est supprimée partiellement ou totalement par la phénoxybenzamine suivant la concentration de bloquant alpha adrénergique utilisée (0.6 M/l ou 6 M/l); elle n'est pas modifiée par le propranolol (1 M/l). — Le propranolol (1 M/l) s'oppose à la première phase stimulante de I'isoprénaline; la phénoxybenzamine (6 M/l) paraÎt s'opposer à la deuxième phase inhibitrice. — 3. Les substances bloquant les récepteurs alpha ou bêta adrénergiques (phénoxybenzamine, propranolol) dont l'étude sur l'insulino-sécrétion a été réalisée à l'aide de concentrations croissantes peuvent manifester des effets très différents suivant la concentration utilisée et suivant la phase au cours de laquelle leur action est étudiée.

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Insulin secretion studied on isolated perfused rat pancreas. II. Effects of catécholamines and adrenergic blocking drugs

Summary Our experiments carried out on isolated perfused rat pancreas, the insulin secretion of which is slightly stimulated by glucose at a concentration of 1.5 g/l, led to the following findings: — 1. L-adrenaline and L-noradrenaline at low concentrations (0.0055 M/l and 0.011 M/l) provoke a marked decrease of insulin secretion. L-adrenaline has a stronger inhibitory effect than L-noradrenalin. At a concentration of 0.05 M/l, L-isoprenaline, first stimulates insulin secretion, then provokes a progressive decrease. — 2. The inhibition provoked by L-adrenaline is partially or totally suppressed by phenoxybenzamine depending on the concentration of the alpha adrenergic blocking drug used (0.6 M/l or 6 M/l); this inhibition is not modified by propranolol (1 M/l). — Propranolol (1 M/l) counteracts the first stimulation phase induced by isoprenaline; phenoxybenzamine (6 M/l) seems to counteract the second inhibitory phase. — 3. The effects of alpha and beta adrenergic blocking drugs (phenoxybenzamine and propranolol) have been studied on insulin secretion using increasing concentrations; these substances exert different effects depending on their concentration and the phase in which their action is studied.

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Untersuchungen der Insulinsekretion am isolierten perfundierten Rattenpankreas. II. Wirkung von Katecholaminen und adrenergen Receptorenblockern

Zusammenfassung Unsere Untersuchungen am isolierten, perfundierten Rattenpankreas, dessen Sekretion durch eine Glucoselösung von 150 mg% leicht stimuliert wurde, erlaubten uns, folgende Tatsachen festzustellen: — 1. Geringe Konzentrationen (0.0055 M/l und 0.011 M/l) von L-Adrenalin und L-Noradrenalin rufen eine erhebliche Verringerung der Insulinsekretion hervor. Diese Hemmwirkung ist bei L-Adrenalin stärker ausgeprägt als bei L-Noradrenalin. Bei einer Konzentration von 0.05 M/l stimuliert L-Isoprenalin zunächst die Insulinsekretion, bewirkt aber später eine fortschreitende Verringerung. — 2. Die durch 1-Adrenalin ausgelöste Hemmung läß sich teilweise oder vollständig durch Phenoxybenzamin aufheben und zwar je nach der verwandten Konzentration dieses Alpha-Receptorenblockers (0.6 M/l oder 6 M/l), sie wird durch 1 M/l Propanolol nicht modifiziert. — Das Propanolol (1 M/l) hemmt aber die erste Stimulationsphase des Isoprenalins; das Phenoxybenzamin (6 M/l) scheint der zweiten Hemmphase entgegen zu wirken. — 3. Die Hemmer der adrenergen - und -Receptoren (Phenoxybenzamin, Propanolol), deren Wirkung auf die Insulinsekretion wir bei steigenden Konzentrationen untersucht haben, können je nach angewandter Konzentration und je nachdem, während welcher Phase man ihren Effekt prüft, ganz verschiedene Wirkungen entfalten.

     

Comparison of 5 vs 10 μg/kg per day of GM-CSF following dose-intensified chemotherapy with cisplatin,etoposide, and ifosfamide in patients with advanced testicular cancer

Summary Despite the increasing use of granulocyte-macrophage colony-stimulating factor (GM-CSF) for the treatment of chemotherapy-induced neutropenia, few studies have focused on the activity and toxicity of the different clinically used dosages of GM-CSF. Forty-four patients with poor-risk (advanced disease, according to the Indiana University classification) testicular cancer were treated with a dose-intensified chemotherapy regimen of cisplatin (30 mg/m²), etoposide (200 mg/m²), and ifosfamide (1.6 g/m²), given on days 1–5 for a total of four cycles at planned intervals of 21 days. Patients (pts) received GM-CSF, either 10 (22 pts; 70 cycles evaluable) or 5 g/kg body wt. daily s.c. (22 pts; 72 cycles evaluable), starting the first day after chemotherapy for 10 consecutive days. Overall, 34 patients (78%) achieved a favorable response (CR or PR with negative tumor markers), six patients (14%) failed this chemotherapy regimen, and four patients (9%) died of therapy-related complications. The durations of both neutropenia and thrombocytopenia increased with the number of treatment cycles given. The duration of granulocytopenia after the fourth PEI cycle was significantly shorter for patients receiving 10 g/kg than for those with 5 g/kg per day of GM-CSF (9 vs 13 days;p<0.05). The median duration of thrombocytopenia <20000/l after the fourth cycle of PEI was also significantly reduced in favor of patients receiving 10 g/kg of GM-CSF (4 vs 9 days;p< 0.02). However, there were no differences in the frequency of severe infections or in the achieved dose intensity. Five patients (11%) discontinued GM-CSF due to side effects (three anaphylactoid-type reactions, one myalgia and fever, one cutaneous toxicity). No difference in the frequency of side effects was seen between patients receiving 5 and those receiving 10 g/kg per day of GM-CSF. The dose of 5 g/kg per day of GM-CSF may be sufficient to ameliorate neutropenia following standard-dose chemotherapy, while higher dosages of GM-CSF may be advantageous in patients receiving repetitive cycles of dose-intensified chemotherapy.     

Serum bile salts as an aid to oral cholecystogram interpretation

A radioimmunoassay for glycocholate was used as an estimate of serum bile salts in patients with serum bilirubin levels less than 5 mg/dl undergoing oral cholecystography. Most subjects also had a percutaneous liver biopsy. Intravenous cholangiography was performed in most subjects who had a nonvisualized gallbladder after receiving single doses of iopanoic acid on two consecutive days. The pathologic status of nonvisualized gallbladders was ascertained by surgery, prospective follow-up, necropsy and/or ultrasound. In 20 subjects with well-visualized gallbladders, the serum cholate conjugates (CC) were lower than 3.5 M in all but two subjects, both of whom had inflammatory liver disease (chronic active hepatitis, alcoholic hepatitis). Those with faintly or poorly visualized gallbladders, but with no evidence of gallbladder or gallstone disease by other criteria, also had levels less than 3.5 M, except for one subject with inflammatory liver disease. By contrast, 11 subjects with nonvisualized, although normal gallbladders by the above clinical criteria, exhibited serum CC greater than 3.5 M. Six subjects had diminished gallbladder visualization, but normal gallbladders on clinicopathological grounds; all but one with chronic active hepatitis had serum CC greater than 3.5 M. In conclusion, when the serum cholate conjugates are less than 3.5 M, nonvisualization of the gallbladder with oral cholecystography supports a diagnosis of a diseased gallbladder. In addition, a serum CC level greater than 3.5 M may predict insufficient hepatic capacity to secrete iopanoic acid adequate for gallbladder visualization in noninflammatory liver disease. The serum cholate conjugates appear to provide greater information on this hepatic function than the serum bilirubin or bromsulfophthalein retention.     

Stimulation of GTP hydrolysis in guinea pig bronchial membranes by mastoparan

Guanine nucleotide-binding proteins, or G proteins, play an important role in transmitting information from membrane receptors to intracellular effector systems. Activation of G proteins results in the hydrolysis of GTP, and the measurement of GTPase activity represents a means by which the role of G proteins in signal transduction can be investigated. GTPase activity of guinea pig bronchial membranes was measured as the liberation of ³²P_i from [-³²P]GTP. GTPase activity was divided into two components, one possessing a high affinity and the other a low affinity for GTP. The contribution of high- and low-affinity GTPase to total hydrolysis was dependent on Mg²⁺. In the presence of submicromolar Mg²⁺, high-affinity GTPase represented 65–80% of all activity, whereas in the presence of 26 µM Mg²⁺, all detectable hydrolysis was due to the low-affinity GTPase. High-affinity GTPase was stimulated by Mg²⁺ in the 0.15–1.1 M range (2.5-fold maximal stimulation, apparent Km for Mg²⁺ 0.31 M). Mastoparan (1–100 M) caused a concentration-dependent stimulation of high-affinity (but not low-affinity) GTPase (71 ± 13% maximal stimulation, EC₅₀ 0.38 M), suggesting that high-affinity GTPase may be due to a G protein. Carbachol (10 M) and fenoterol (10 M) had no effect on high-affinity GTP hydrolysis, suggesting that under the conditions described, GTPase activity of bronchial membranes is not activated by muscarinic or -adrenergic receptors, respectively. Offprint requests to: K. J. Rhoden     

The cutoff value of serum ferritin for the diagnosis of iron deficiency in community-residing older persons

The serum ferritin assay is the best single blood test for the diagnosis of iron deficiency. Previous studies with elderly anemic patients have suggested that ferritin level less than 45 g/L is indicative of iron deficiency. The subjects of these studies were hospitalized patients with anemia, however. We thus conducted a prospective study to determine the normal minimum level of serum ferritin of community-dwelling older adults by assessing the ratio of serum transferrin receptor to the log ferritin level (sTfR-F index). We conducted the anemia survey between October and November 2002. A total of 1,254 apparently healthy older adults, aged between 60 and 95 years, from three urban community dwellings participated in the survey. Among these individuals, 156 subjects who were anemic or whose serum ferritin level was less than 100 g/L were selected. The soluble transferrin receptor assay was performed and the sTfR-F index was calculated. The receiver operating characteristic curve analysis was performed. Based on the data, serum ferritin level of 22 g/L was selected as the cutoff value for the diagnosis of iron deficiency in community-dwelling older adults. Applying the serum ferritin cutoff of 22 g/L and the sTfR-F index cutoff of 1.5, the sensitivity of the assay was 89.5% (34 of 38) and the specificity was 89.0% (105 of 118). In conclusion, for the diagnosis of iron deficiency of community-residing older adults, we suggest the serum ferritin cutoff value of 22 g/L obtained by use of the sTfR-F index. The value is lower than the previous value established for hospitalized and anemic older adults.     

Differential cell count and lymphocyte subsets in bronchoalveolar lavage during pneumonia with and without peripheral neutropenia

One hundred immunocompromised HIV negative patients with microbiologically positive pneumonia underwent bronchoalveolar lavage (BAL) studies. Thirty cases showed peripheral neutropenia (<1000 neutrophils/L), 70 did not. The total cell number in BAL, the differential cell counts, and the lymphocyte subsets (CD4, CD8, CD19, CD57) were measured. Patients with pneumonia and normal or elevated peripheral neutrophils had a significantly increased total number of cells in BAL compared to patients with peripheral neutropenia (3,2 ± 2 vs 1,3 ± 0,6 × 105 cells/ml lavage fluid, p < 0.01). Ninety percent of the BAL differential cell counts obtained in patients exceeding 1000 neutrophils/L showed a lymphocytic and/or neutrophilic alveolitis, whereas only 54% of patients with peripheral neutropenia displayed abnormal counts (p < 0.01). Yet the typical pattern of neutrophilic alveolitis was found more often for peripheral neutrophil counts over 1000/L with high significance (p < 0.0001). Abnormal BAL cell patterns for neutropenic patients uniformly showed a lymphocytic alveolitis, only 10% additionally conformed with the pattern of neutrophilic alveolitis. Patients with pneumonia with and without peripheral neutropenia had similar findings in BAL lymphocyte subsets and exhibited a reduced CD4/CD8 ratio compared to controls (p < 0.05). The high susceptibility of severe neutropenic patients to pulmonary, especially fungal infections may be explained by the local lack of neutrophils.

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Ergonovine-induced constrictions of epicardial coronary arteries in conscious dogs: α-adrenoceptors are not involved

Summary The effect of i.v. ergonovine tartrate infusions (0.05–20 g/kg/min, 12 minutes duration) on coronary arteries was studied in 14 conscious dogs instrumented to continuously measure vascular diameter by an ultrasonic dimension gauge using 10-MHz piezoelectric crystals.Ergonovine induced a biphasic coronary response: small, transient dilation during the first minutes of infusion, followed by slowly developing constriction reaching its maximum 5 to 15 minutes after the end of the infusion and persisting at this level for at least 10 minutes. The threshold dosage for significant constriction was 0.05 g/kg/min. A dosage of 5 g/kg/min (cumulative 60 g/kg, corresponding to 35 g/kg ergonovine maleate) caused a decline in mean left circumflex artery diameter by 137±15 m (=4.6%) without significantly altering heart rate, plasma catecholamines or plasma renin activity. Coronary venous O₂ saturation did not decline, indicating the absence of coronary resistance vessel constriction. The epicardial artery constriction was not attenuated by a vasopressin antagonist. Under adrenergic blockade (2 mg/kg phentolamine and 2 mg/kg nadolol) or under ganglionic blockade (5 mg/kg pentolinium tartrate), ergonovine (5 g/kg/min) caused substantial elevation in mean arterial pressure, while the decline in coronary artery diameter was attenuated. When this increase in arterial pressure was prevented by appropriate bleeding, the ergonovine-induced coronary constriction was not diminished by adrenergic or ganglionic blockade. The serotonin antagonist methysergide (0.5 mg/kg) completely abolished the ergonovine-induced coronary artery vasomotion.It is concluded that ergonovine in dogs causes an epicardial coronary artery constriction comparable to the diffuse coronary artery narrowing in men not suffering from variant angina pectoris. These constrictions are not mediated by an adrenergic mechanism.Supported by Deutsche Forschungsgemeinschaft. Dedicated to Prof. Dr. A. Fleckenstein on the occasion of his 65th birthday.     

Modulation of multidrug resistance by BIBW22BS in blasts of de novo or relapsed or persistent acute myeloid leukemia ex vivo

The phenylpteridine derivative BIBW22BS (BIBW22) is a potent modulator of multidrug resistance (MDR). We investigated BIBW22 in comparison to dexniguldipine and verapamil as modifier of MDR in blasts of de novo, relapsed or persistent acute myeloid leukemia (AML) in vitro. All patients with relapsed or persistent AML had been pretreated with idarubicin and cytosine arabinoside. The degree of MDR was determined by efflux kinetics of rhodamine 123 (R123), daunorubicin, and idarubicin measured by flow cytometry (FACS). A total of 51 patients with AML, 25 de novo and 26 relapsed or persistent, were investigated. While only 6 out of 25 de novo AML blast populations showed moderate efflux of R123 and daunorubicin, 17 out of 26 blast populations of relapsed or persistent AML had an efflux between 20% and 44% within 15 min ex vivo. This efflux could be significantly inhibited by 1 M BIBW22, 1 M dexniguldipine, or 10 M verapamil. For idarubicin we found an effusion of 40±9% within 15 min in all blast populations that could not be inhibited by the modulators. Clinically achievable drug concentrations causing only moderate side-effects are in the range of 0.5 M dexniguldipine and 3 M verapamil. Up to now, BIBW22 has not been investigated clinically. Thus, the potential toxicity of concentrations of 0.5–1 M BIBW22, sufficient for an optimal efflux inhibition ex vivo, is not known yet. We conclude from our ex vivo investigations in blast populations of de novo, relapsed or persistent AML that BIBW22 is a potent modulator of MDR.Abbreviations AML acute myeloid leukemia - MDR multidrug resistance     

Antiproliferative activity of the non-myelotoxic antitumour agent of plant origin,Thaliblastine, on two human glioma cell lines

Summary The antiproliferative activity of the non-myelotoxic antitumour agent of plant origin, Thaliblastine, on two human glioma cell lines is described. Thaliblastine was added once one day following start of culture; proliferation was monitored over 7 days. The anti-proliferative activity of Thaliblastine was strongly dependent on concentration and time of incubation. The ID₅₀ of Thaliblastine in T406 and GW27 glioma lines was 5.1 g/ml and 8.2 g/ml (7.0 M and 11.2 M), respectively.Abbreviation TBL Thaliblastine     

Normal Ascorbic Acid in Cerebrospinal Fluid of Patients with Infantile Neuronal Ceroid-Lipofuscinosis

Neuronal ceroid-lipofuscinoses (NCL) are a group of neurodegenerative disorders. There is much evidence for a role of peroxidation processes in the pathogenesis of NCL, although this would certainly be indirect. Reduced total antioxidant activity of cerebrospinal fluid (CSF) has been reported in NCL. Since ascorbic acid represents a major antioxidant in CSF, we have now determined this parameter in CSF of two patients with the infantile form of NCL (Santavuori-Haltia disease). However, the ascorbic acid values obtained (103.6 and 181.3 M) are comparable with control values from the literature as well as with those measured in groups of children with neurologic/psychiatric diseases other than NCL (mean ± standard deviation: 137.1±41.3 M), with suspected (but excluded) meningitis (124.1±34.0 M) and acute lymphoblastic leukemia (131.7±17.0 M). Our results indicate that CSF ascorbic acid concentrations are not affected by peroxidation processes in infantile NCL, but reveal a sharply decreased ascorbic acid concentration in one of the non-NCL patients, possibly associated with his convulsions and/or his anticonvulsant therapy.     

A sensitive double antibody radioimmunoassay for Human Growth hormone (HGH): levels of serum HGH following rapid tolbutamide infusion

Summary A double antibody radio-immunoassay for human growth hormone is described. — The assay can detect 0.0625 mg HGH/ml serum and has good reproducibility. It was found that: 1. a highly pure labelled hormone; 2. a specific and very potent guinea pig antihuman growth hormone antibody; and 3. at least five days of incubation for the first reaction were necessary to achieve this accuracy and sensitivity. -Porcine and rat growth hormone, sera from cow, guinea pig, rabbit, mouse, and toad fish did not react with the guinea pig anti-HGH serum used in the assay. — In four patients after hypophysectomy, HGH concentrations disappeared almost completely, and in another patient no rise of the hormone was seen during an IV insulin tolerance test.-Undiluted human serum appears to produce falsely high levels of HGH. — Normal males exhibited fasting HGH levels from 0 –2.2 mg/ml (mean 0.8 mg/ml). Females ranged from 0.6–15.0 mg/ml (mean 5.1 mg/ml) and 15 acromegalics from 8.0–103.0mg/ml (mean 31.2 mg/ml). — During a rapid tolbutamide tolerance test, serum HGH rose between 2.5- and 82-fold over the fasting levels within 10 to 70 minutes following the glucose nadir.Performed in part during a postdoctoral fellowship Stiftung Volkswagenwerk, Germany.     

Tannin inhibition of protein kinase C in airway epithelium

Tannin, a polydisperse polyphenol extracted from cotton bracts (CBE), has been implicated in the pathogenesis of byssinosis, a lung disease of mill workers. CBE tannin inhibits chloride secretion in airway epithelial cells by means of an unknown mechanism(s). Activation of protein kinase C (PKC) by PMA (phorbol 12-myristate 13-acetate) in airway cells increases chloride secretion. The effect of tannin on this PKC pathway was examined, using canine tracheal epithelium mounted in Ussing chambers. PMA addition (10 nM) to the mucosal bath resulted in a 0.36 ± 0.07 Eq/cm² · h (mean ± SEM, n = 20) increase in short-circuit current (I_sc) and a 0.38 ± 0.17 Eq/cm² · h increase in net chloride secretion (J_net). The inactive 4-phorbol had no effect. Tannin addition to the mucosal bath produced a dose-dependent decrease in I_sc and J_net. In tissues pretreated with 2–50 g/ml tannin, and subsequently stimulated with PMA, tannin inhibited PMA stimulation of chloride secretion beginning at a tannin concentration of 10 g/ml (0.09 ± 0.05 Eq/cm² · h [n = 10] increase in I_sc and 0.08 ± 0.03 Eq/cm² · h increase in J_net with PMA after tannin pretreatment). At 50 g/ml tannin, the stimulatory effect of PMA was completely abolished. The known PKC inhibitor, H-7 (20 M), inhibited PMA stimulation, while chelerythrine (2 M) had not effect on PMA-stimulated I_sc and J_net, and calphostin C was toxic to the airway epithelium. In membrane fragments, 2.5 g/ml tannin inhibited the rate of histone III phosphorylation by PMA from 32.1 ± 4.4 nmol/mg protein per min to 20.1 ± 2.7 nmol/mg protein per min (n = 7). In bovine airway cells, tannin pretreatment (2.5 g/ml) decreased the cytosolic activity of PKC but had no effect on PKC translocation to the membrane. We conclude that tannin inhibits chloride secretion in airway epithelial cells in part by inhibiting PKC.Offprint requests to: Michelle M. Cloutier     

Incipient nephropathy in Type 1 (insulin-dependent) diabetes

Summary Patients with Type 1 (insulin-dependent) diabetes without proteinuria were studied to define those patients who will later develop persistent proteinuria (more than 0.5 g protein/24 h). Two investigations were performed; 71 patients were studied longitudinally for 6 years and another 227 patients were studied cross-sectionally. All were less than 50 years of age and had developed diabetes before the age of 40 years. At entry into the study they had no proteinuria (Albustix method), had normal blood pressure and urinary albumin excretion rates < 200 g/min (normal 20 g/min). The best predictor of persistent proteinuria or an albumin excretion rate > 200 g/min was the initial urinary albumin excretion rate. During the longitudinal study, seven patients with an urinary albumin excretion rate of more than 70 g/min at the start of the study developed persistent proteinuria or an albumin excretion rate > 200 g/min. In contrast, only three out of the remaining 64 patients with urinary albumin excretion rate 70 g/min developed urinary albumin excretion rate > 200 g/min. Patients with an urinary albumin excretion rate > 70 g/min are thus at risk of developing diabetic nephropathy. We designate this stage of renal involvement incipient nephropathy. Patients with incipient nephropathy were further characterized in the cross-sectional study. Compared with normoalbuminuric patients, patients with incipient nephropathy had increased systolic and diastolic blood pressure, but normal serum creatinine. The glomerular filtration rate was higher than normal in patients with incipient nephropathy though not different from that of normoalbuminuric patients.     

Age-related Variations in the Neuroendocrine Control,More Than Impaired Receptor Sensitivity,Cause The Reduction in the GH-releasing Activity of GHRPs in Human Aging

The mechanisms underlying the reduction in the GH-releasing activity of GHRPs in aging are still unclear. Aim of our study was to verify in man whether age-related impairment of the neurohormonal control of GH secretion and/or receptor alterations are involved in the reduced GH response to GHRPs in aging. To this goal, in 16 normal elderly subjects (E, 66–81 yr) and 12 young controls (Y, 24–28 yr) we studied the effects of 1.0, 2.0 and 3.0 g/kg iv Hexarelin (HEX), a synthetic hexapeptide, or GHRH, as well as the interaction among HEX (2.0 g/kg), GHRH (2.0 g/kg) and arginine (ARG, 0.5 gr/kg) on GH secretion. In Y the GH response to increasing doses of HEX (1.0 vs. 2.0 vs. 3.0 g/kg; AUC0;v–120 ± SEM: 1728.4 ± 406.4 vs. 2265.9 ± 298.4 vs. 2934.3 ± 482.2 g//L/h, p < 0.05 for 1.0 vs. 2.0 g/kg) and GHRH (649.6 ± 111.4 vs. 792.2 ± 117.6 vs. 1402.6 ± 363.0 g/L/h) showed a progressive increase. Two g/kg HEX and 1 g/kg GHRH were the maximal effective doses. Similarly, in E the GH response to increasing doses of HEX (336.7 ± 50.0 vs. 742.8 ± 157.9 vs. 1205.1 ± 178.1 g/L/h, p < 0.05 for 1.0 vs. 2 g/kg, p < 0.001 for 1.0 vs. 3.0 g/kg and p < 0.03 for 2.0 vs. 3.0 g/kg) and GHRH (183.8 ± 27.3 vs. 260.9 ± 17.3 vs. 356.1 ± 46.3 g/L/h, p < 0.005 for 1.0 vs. 3.0 g/kg and p < 0.05 for 2.0 vs. 3.0 g/kg) showed a progressive increase. In E the GH response to 3 g/kg HEX or GHRH were clearly higher than those to 2 g/kg. However, at each dose the GH responses to HEX or GHRH in E were lower (p < 0.05) than those in Y. In Y the GH response to HEX + GHRH was synergistical (4259.2 ± 308.0 g/L/h, p < 0.05). ARG strikingly potentiated the GHRH-induced GH rise (2640.8 ± 273.6 g/L/h, p < 0.01) but not the HEX-induced one (2371.7 ± 387.2 g/L/h) as well as the synergistical effect of HEX and GHRH (4009.1 ± 360.8 g/L/h). In E the GH response to HEX and GHRH was still synergistical (1947.7 ± 306.0 g/L/h, p < 0.05) but these responses were lower than those in young (p < 0.01). On the other hand, in E ARG restored the GH response to GHRH (1858.9 ± 172.8 g/L/h, p < 0.01) and even those to HEX (2069.5 ± 528.7 g/L/h, p < 0.01) and HEX + GHRH (4406.0 ± 1079.2 g/L/h, p < 0.05). Our present results indicate that the impairment of GHRP and GHRH receptor activity may have a role in the reduction of the somatotrope responsiveness in aging. However, the age-related reduction in the GH-releasing activity of GHRPs seems mainly dependent on age-related variations in the neural control, i.e. concomitant GHRH hypoactivity and somatostatinergic hyperactivity.     

Induction and activation of procollagenase in rabbit synovial fibroblasts after treatment with active oxygen released by xanthine/xanthine oxidase

Treatment of rabbit synovial fibroblasts with active oxygen (AO) released by xanthine/xanthine oxidase resulted in an induction of procollagenase in these cells in concentrations ranging from 12.5 g/ml xanthine plus 0.0025 U/ml xanthine oxidase to 50 g/ml xanthine plus 0.01 U/ml xanthine oxidase. Preceding this there was an accumulation of poly(ADP-ribose) for the same concentration range of xanthine/xanthine oxidase. Furthermore, it was found that AO caused activation of the latent procollagenase to the active enzyme in concentrations ranging from 0.1 g/ml xanthine plus 0.00002 U/ml xanthine oxidase to 1 g/ml xanthine plus 0.0002 U/ml xanthine oxidase. It is suggested that poly(ADP-ribosyl)ation participates in the induction of procollagenase by relaxing chromatin. Furthermore, it is proposed that AO activates latent procollagenase under physiological conditions.