Vasoconstrictor and vasodilator effects of guanine nucleotides in the rat aorta

Although GTP, like ATP and UTP, is stored in platelet dense granules, little is known about its vascular effects. The present study was carried out in order to characterize the effects of GTP and related compounds in the rat aorta. Contractions were examined in aortic rings at resting tension. In rings with intact endothelium, GTP, GDP, guanosine 5’-O-(3-thiotriphosphate) (GTPγS) and guanosine 5’-O-(2-thiodiphosphate) (GDPβS) caused small contractions. In endothelium-denuded rings, the contractions were unchanged or increased and persisted after desensitization of P2X-receptors by α,β-methylene ATP. Relaxations were examined in aortic rings precontracted with noradrenaline. In rings with intact endothelium, GTP (EC₅₀ 131μM), GDP (no maximal effect obtained), GTPγS (EC₅₀ 6.8μM) and guanosine (EC₅₀ 822μM) caused prominent relaxation, whereas GDPβS caused further contraction. In endothelium-denuded rings, the relaxant effect of GTP was greatly reduced, that of GDP and guanosine was unchanged, and that of GTPγS was abolished. Relaxations by GTP and GTPγS in endo-thelium-intact rings were studied in more detail. The relaxation by GTP was slightly and the relaxation by GTPγS greatly reduced after treatment with N^G-nitro-L-arginine methyl ester. Pre-exposure to a high concentration of the P2Y-receptor agonist 2-methylthio ATP (MeSATP) did not attenuate the effects of GTP and GTPγS. Four compounds previously identified as antagonists at the P2Y- and P2U-receptors of rat aortic endothelium – suramin, reactive blue 2, pyridoxalphosphate-6-azophenyl-2’,5’-disulphonate (iso-PPADS) and 5,5’-(1,1’-biphenyl-4,4’-diylbisazo)-bis-7-amino-6-hydroxy-naphthalene-1,4-disulphonate (NH05) – were tested against GTP and GTPγS. Suramin, reactive blue 2 and iso-PPADS were much less potent against GTP and GTPγS than previously found against (the P2Y effect of) MeSATP. Suramin, iso-PPADS and NH05 were about as potent against GTP and GTPγS as previously found against (the P2U effect of) UTP and in particular ATP. It is concluded that guanine nucleotides can cause both contraction and relaxation of the rat aorta. The high concentrations of GTP and GDP required, and in the case of contraction the small size of the response, make a physiological role of the vascular effects of these nucleotides unlikely. GTP and GTPγS elicit endothelium-dependent relaxation through P2U-receptors. GTP in addition relaxes the aorta through smooth muscle receptors, possibly by way of its degradation product guanosine. The stable analog GTPγS is a relatively potent and selective agonist for the endothelial P2U-receptor. Received: 21 March 1997 / Accepted: 31 July 1997     

The use of machine punch cards and their mode of processing in the framework of studies of large groups of patients]

The authors describe the use of machine punch cards in the framework of the examination of a great group of subjects and present a processing scheme. They advocate the use of this technique in case of abundance of informations and relatively simple questions.     

Distorted body image in bulimic women

Fifteen bulimic women (DSM III) and 15 women with no indication of an eating disorder, matched pairwise with respect to age, weight and height, were assessed via a distorting video image technique under four conditions. They were asked to: (1) estimate the width of a water bottle, (2) estimate the width of their own body, (3) repeat those estimates under a condition of reward for high accuracy, (4) focus attention on their bodily sensations and indicate how wide their body felt. While groups did not differ in their estimates under condition 1 (water bottle), significant differences were found between groups under conditions 2, 3 and 4 (own body), the percentage of overestimating being highest when subjects were to indicate how wide their body felt. Results suggest that modalities of perception other than visual are strongly involved in the body image distortion of bulimics.     

Frequency and prevalence of anomalies in shape, number and structure in locally limited disorders of the odontogenesis

Anomalies in shape, number and structure of deciduous and permanent teeth in patients with different kinds of clefts are a sign of a disturbed developmental process. Their localisation, typically in the immediate vicinity of the cleft formation, and their exclusive presence at the upper medium and lateral incisors led to the presumption of a direct correlation with the genesis of the cleft formation. An early preventive individual care and the consequent complex stomatological therapy are a prerequisite for the realization of the morphological, functional and aesthetic conditions that effectively assist in the social accommodation of patients with different kinds of clefts.     

Dysfunctional cognitions, attributional style, and depression bulimia

A group of 44 bulimic women (DSM-III) as well as 38 women with no indication of an eating disorder, comparable with respect to age, weight and height, were studied by mean sof the Beck Depression Inventory (BDI), the Dysfunctional Attitute Scale (DAS), the Attributional Style Questionnaire (ASQ), and an Eating Disorder Questionnaire (EDQ),. Bulimics showed significantly higher BDI, DAS and ASQ (bad events) score, respectively. In both BDI cores were significantly correlated with DAS and ASQ (events) results. BDI was highly predictive of severity of bulimia while no significant prediction was obtained from either DAS or ASQ (bad events) scores. The findings provide first evidence that dysfunctional attitudes and dpressive and depressive attributional style are predominant i bulimic women but at the same time are not necessarily predictive of the severity of the disorder.     

A statistical analysis of the release of acetylcholine at newly formed synapses in striated muscle

1. A statistical analysis has been made of the changes in the binomial parameters n and p during transmitter release from motor-nerve terminals when synapses are forming in either regenerating or reinnervated mammalian muscle.2. The amplitude-frequency distribution of e.p.p.s evoked by a single impulse was well predicted by binomial statistics at all junctions analysed allowing values of n and p to be determined. At most of these junctions, p > 0.5 and Poisson statistics did not predict the observed distributions at all.3. During the changes in quantal content which occur during short trains of impulses or during continual stimulation over minutes, no significant change in p was detected. Changes in quantal content of the e.p.p. were therefore determined by n.