Adrenergic stimulation of isolated rat gastric mucosal cells

Summary Adrenergic stimulation of the adenylate cyclase (AC)-cAMP-system and ¹⁴C-aminopyrine accumulation, an indirect measure of parietal cell H⁺-production, was studied in different preparations of gastric mucosal cells.The ₂-adrenoceptor agonist hexoprenaline activated AC of crude homogenates from the gastric corpus of mouse, rat, guinea-pig, hog, dog and man. In isolated rat gastric cells (20% parietal cells), treated by low power sonication, 10^–8 to 10^–3 mol/l adrenaline and hexoprenaline activated AC equally potently and efficaciously by maximally 170%. Isoprenaline proved to be less effective activating up to 80%. 5·10^–5 mol/l GMP-PNP augmented basal activity 8.5 times and reduced the maximal efficacy. Adrenaline and hexoprenaline activated AC by maximally 120%, isoprenaline by 40%. The potency of adrenaline was 4 times lower, that of hexoprenaline 2 and that of isoprenaline 4 times higher in the presence of GMP-PNP. Adrenergic stimulation was inhibited by the -adrenoceptor antagonist propranolol, the effect of -adrenoceptor-blockade by phenoxybenzamine was less pronounced. In fractions with 7–80% of parietal cells, prepared by isopycnic centrifugation with Percoll, adrenaline and hexoprenaline activated AC or hexoprenaline enhanced the cellular level of cAMP in parietal cell poor and rich fractions. The degree of activation in response to histamine correlated with the number of parietal cells. ¹⁴C-Aminopyrine uptake was increasingly stimulated through 10^–8 to 10^–5 mol/l hexoprenaline, maximally by doubling the basal accumulation. 10^–4 mol/l histamine was 8 times more effective. 3·10^–7 mol/l propranolol inhibited the effect of 10^–5 mol/l hexoprenaline by 80%.The data suggest the localization of -adrenoceptors (likely -adrenoceptor) on parietal and other nonidentified gastric cells. At the parietal cell, adrenaline and hexoprenaline initiate activation of AC and hexoprenaline leads to H⁺-production. The responses are small compared to the effect of histamine. Thus, -adrenoceptor agonists exert intrinsic activity in relation to H⁺-production. Their influence on stimulated secretion of isolated cells remains to be elucidated.     

Clonidine-induced locomotor hyperactivity in rats

Summary The -adrenergic agonist, clonidine, causes sedation in normal rats. The present study demonstrates that clonidine evokes strong locomotor stimulation in rats pretreated with 6-hydroxydopamine plus reserpine. Similar, but less intensive hyperactivity is observed in rats given clonidine after combined pretreatment with 6-hydroxydopamine plus p-chlorophenylalanine plus -methyl-p-tyrosine, or with reserpine plus low doses of yohimbine. The -adrenolytic drugs, phenoxybenzamine, phentolamine and aceperone, as well as high doses of yohimbine, antagonise the clonidine-induced locomotor stimulation; in contrast, the dopamine receptor blocking agents, pimozide and spiroperidol, exert no antagonistic effect. The results indicate that in the brain of normal animals, clonidine predominantly activates presynaptic -adrenoceptors on noradrenergic neurones and thereby induces sedation. After destruction of the noradrenergic fibres by 6-hydroxydopamine plus reserpine, activation of postsynaptic -adrenoceptors prevails so that hyperactivity results.This study was supported by Polish Academy of Sciences (10.4). Preliminary accounts were presented at the Pharmacology Meeting, Hannover, September 14–17, 1976 and at the 1 st Joint Symposium of Hungarian and Polish Pharmacological Societies, Zakopane, October, 13–15, 1976     

Effect of therapeutic drug monitoring of amitriptyline and genotyping on efficacy and safety of depression therapy

Modern pharmacotherapy is based on precise adjustment of a dosage schedule to individual requirements of patient. Therapeutic drug monitoring is a method that allows for a more effective treatment approach, especially in the case of a narrow therapeutic index of a drug. Tricyclic antidepressant drugs are characterised by narrow therapeutic index as well as relationship between serum drug concentration and side effects. It was demonstrated that interindividual variability of blood concentrations of tricyclic antidepressant drugs is related to genetic polymorphism of oxidating enzymes participating in metabolism of these drugs. The aim of the study was to estimate the impact of therapeutic drug monitoring of tricyclic antidepressant drugs as well as genotyping on efficacy and safety of endogenous depression therapy. The study included 9 patients with established diagnosis of endogenous depression. Blood serum concentrations of amitryptyline was measured by fluorescence polarisation immune assay (FPIA, Abbott system). Genotype of cytochrome P450 isoenzyme CYP2D6 was determined using PCR-RFLP method. It was demonstrated that monitoring therapy of tricyclic antidepressant drugs in combination with determination of the genotype seems to be more safe and effective. Monitoring therapy and genotyping may be less expensive than the costs of prolonged hospitalisation and risk of side effects.     

Assessment of blood flow velocity during cognitive stimulation in persons with suspected hydrocephalus

The aim of this work is to evaluate middle cerebral arteries (MCA) blood flow velocity changes during performance of linguistic and visuospatial cognitive tasks. Two groups were investigated: eight patients with suspected hydrocephalus without perceptible cognitive disturbances, and eight healthy persons. Blood flow velocity in left and right MCA was recorded with transcranial Doppler sonography while the examined patients were performing three different tasks. The analysis of the results showed differences between the groups concerning both increase of blood flow velocity values and performance patterns. Compared to healthy individuals less increase in blood flow velocity during performance of all tasks and no difference in haemodynamic changes between both hemispheres during task performance were observed in patients with hydrocephalus. The results obtained suggest, that the pattern of functional lateralization in brain in patients with suspected hydrocephalus is probably changed.     

The effects of acamprosate and neramexane on cue-induced reinstatement of ethanol-seeking behavior in rat.

This study examines, for the first time, the effects of acamprosate and the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist neramexane on ethanol-seeking induced by alcohol-related environmental stimuli in an animal model of relapse. Wistar rats were trained to operantly self-administer ethanol (10% w/v) or water on a fixed-ratio 1 schedule in a 30-min daily session. Ethanol availability was signaled by an olfactory discriminative stimulus of orange extract (S+). In addition, each lever press was accompanied by a 5-s illumination of the operant chamber's house light (CS+). Water availability was signaled by anise odor (S-) and 5-s white noise stimulus (CS-). After completion of the conditioning phase, indicated by stable levels of responding, operant behaviors were extinguished. Prior to reinstatement tests, animals were divided into groups according to either treatment with acamprosate (100, 200 mg/kg given twice), neramexane (1.0, 2.0, 4.0 mg/kg), or vehicle. In vehicle-treated rats, re-exposure to the S+/CS+ in the absence of further ethanol availability elicited strong recovery of responding. No effect was observed following presentation of water-paired cues (S-/CS-). Acamprosate dose-dependently attenuated recovery of responding elicited by ethanol-paired cues (S+/CS+), whereas responding under S-/CS- was not modified by drug administration. Treatment with 1.0 and 2.0 mg/kg of neramexane did not significantly modify responding under both S+/CS+ and S-/CS- conditions. However, a slight reduction of cue-induced reinstatement of alcohol seeking was observed. At the dose of 4.0 mg/kg, neramexane elicited a marked inhibition of responding following presentation of both ethanol- and water-paired cues. In conclusion, acamprosate significantly and selectively reduced alcohol-seeking elicited by environmental stimuli predictive of alcohol availability. Treatment with neramexane that shares part of the pharmacological effects of acamprosate on NMDA receptors, however, resulted in a nonselective reduction of lever responding.     

Neuroprotective and symptomatological action of memantine relevant for alzheimer’s disease — a unified glutamatergic hypothesis on the mechanism of action

The involvement of glutamate mediated neurotoxicity in the pathogenesis of Alzheimer's disease is finding increasingly more acceptance in the scientific community. Central to this hypothesis is the assumption that in particular glutamate receptors of the N-methyl-D-aspartate (NMDA) type are overactivated in a tonic rather than a phasic manner. Such continuous mild activation leads under chronic conditions to neuronal damage. Moreover, one should consider that impairment of plasticity (learning) may result not only from neuronal damage per se but also from continuous activation of NMDA receptors. To investigate this possibility we tested whether overactivation of NMDA receptors using either non-toxic doses/concentrations of a direct NMDA agonist or through an indirect approach--decrease in magnesium concentration--produces deficits in plasticity. In fact NMDA both in vivo (passive avoidance test) and in vitro (LTP in CA1 region) impaired learning and synaptic plasticity. Under these conditions memantine which is an uncompetitive NMDA receptor antagonist with features of "improved magnesium" (voltage dependence, affinity) attenuated the deficit. The more direct proof that memantine can act as a surrogate for magnesium was obtained in LTP experiments under low magnesium conditions. In this case as well, impaired LTP was restored in the presence of therapeutically relevant concentrations of memantine (1 microM). In vivo, doses leading to similar brain/serum levels produce neuroprotection in animal models relevant for neurodegeneration in Alzheimer's disease such as neurotoxicity produced by inflammation in the NBM or beta-amyloid injection to the hippocampus. Hence, we postulate that if in Alzheimer's disease overactivation of NMDA receptors occurs indeed, memantine would be expected to improve both symptoms (cognition) and slow down disease progression because it takes over the physiological function of magnesium.     

The effective dose (Deff) for electron beams.

BACKGROUND AND PURPOSE: Calculation of the effective dose and proposal of a dose specification method for the electron beams. PATIENTS AND METHODS: In a homogenous water phantom the 3D dose distributions for electron beams of energy 6, 9, 12, 15, 18 and 21 MeV and beam size 10x10 cm were calculated. For a volume encompassed with 80, 85 and 90% isodose, the mean dose and the SD were calculated for each energy. Using the Brahme's formulae, the effective dose was calculated. RESULTS: The larger the minimum dose (value of the encompassing isodose), the larger the mean dose and the smaller the SD. The mean doses and SD to the volume encompassed with 80, 85 and 90% are in the range of 91-94%, and 5.1-6.2%, 93-96% and 4.2-4.6%, 94-96% and 3.0-3.2%, respectively. Thus the effective dose for the volume encompassed with 80, 85 and 90% are about 90, 93 and 95%, respectively. CONCLUSION: Taking into account the requirements regarding dose uniformity within the PTV and the sparing effect for normal tissue situated under the PTV, we propose to keep the 85% isodose as a minimum one and to prescribe the dose to the 90% isodose. The present method may be applied for single electron beams and typical cases.     

Cardiovascular adverse events in patients with chronic lymphocytic leukemia receiving acalabrutinib monotherapy: pooled analysis of 762 patients

Cardiovascular (CV) toxicities of the Bruton tyrosine kinase (BTK) inhibitor ibrutinib may limit use of this effective therapy in patients with chronic lymphocytic leukemia (CLL). Acalabrutinib is a second-generation BTK inhibitor with greater BTK selectivity. This analysis characterizes pooled CV adverse events (AE) data in patients with CLL who received acalabrutinib monotherapy in clinical trials (clinicaltrials gov. Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02029443","term_id":"NCT02029443"}}NCT02029443, {"type":"clinical-trial","attrs":{"text":"NCT02475681","term_id":"NCT02475681"}}NCT02475681, {"type":"clinical-trial","attrs":{"text":"NCT02970318","term_id":"NCT02970318"}}NCT02970318 and {"type":"clinical-trial","attrs":{"text":"NCT02337829","term_id":"NCT02337829"}}NCT02337829). Acalabrutinib was given orally at total daily doses of 100–400 mg, later switched to 100 mg twice daily, and continued until disease progression or toxicity. Data from 762 patients (median age: 67 years [range, 32–89]; median follow-up: 25.9 months [range, 0–58.5]) were analyzed. Cardiac AE of any grade were reported in 129 patients (17%; grade ≥3, n=37 [5%]) and led to treatment discontinuation in seven patients (1%). The most common any-grade cardiac AE were atrial fibrillation/flutter (5%), palpitations (3%), and tachycardia (2%). Overall, 91% of patients with cardiac AE had CV risk factors before acalabrutinib treatment. Among 38 patients with atrial fibrillation/flutter events, seven (18%) had prior history of arrhythmia or atrial fibrillation/flutter. Hypertension AE were reported in 67 patients (9%), 43 (64%) of whom had a preexisting history of hypertension; no patients discontinued treatment due to hypertension. No sudden cardiac deaths were reported. Overall, these data demonstrate a low incidence of new-onset cardiac AE with acalabrutinib in patients with CLL. Findings from the head-to-head, randomized trial of ibrutinib and acalabrutinib in patients with high-risk CLL (clinicaltrials gov. Identifier: {"type":"clinical-trial","attrs":{"text":"NCT02477696","term_id":"NCT02477696"}}NCT02477696) prospectively assess differences in CV toxicity between the two agents.     

Sexual Functioning in Female Patients Undergoing Surgical Treatment for Colorectal Cancer—A Single-Center,Prospective Triple Timepoint Yearly Follow-Up

The study was aimed at assessing the quality of sexual functioning in female patients having undergone surgical treatment for cancer depending on the type of surgery. The prospective cohort consisted of 48 female patients (23 patients with stoma [A2] and 25 patients with maintained continuity of the GI tract [A1]). Study methods included a diagnostic survey and the analysis of medical records of patients. Research tools consisted of a standardized FSFI questionnaire and a proprietary form for evaluation of sociodemographic data. Measurements were performed at threetimepoints: On the day before the surgery (Measurement I) as well as six and 12 months after the surgery (Measurements II and III, respectively). Statistically significant differences in results were observed in Measurements II and III in the subscales of arousal (II:p = 0.0068, III:p = 0.0018), lubrication (II:p = 0.0221, III:p = 0.0134), orgasm (II:p = 0.0044, III:p = 0.0021), satisfaction (II:p = 0.0021, III:p = 0.0433), and pain/discomfort (II:p = 0.0343, III:p = 0.0473). In all cases, lower scores corresponding to lower quality of sexual functioning were observed in patients in whom stoma had been performed. Statistically significant differences in sexual functioning were observed at Measurements II and III in each group, with the results being significantly (p > 0.05) worse in patients having undergone Hartmann’s procedure or abdominoperineal resection). Variables significantly affecting self-assessed sexual satisfaction included marital status, age, and modality of neoadjuvant treatment. Restoration of the continuity of the gastrointestinal tract is a chance for better self-assessment of the patient’s quality of life as regards sexual functioning.