Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

We tested whether the physiological effects of smoking a cigarette under standard conditions in a laboratory are similar to those seen in a room at home. On two separate test days ten healthy smokers were prepared with a small physiological recorder and were then requested to carry out a protocol requiring them to smoke one of their cigarettes in their usual way either (1) in the laboratory where they had never smoked previously, or (2) at home, alone in a quiet room where they regularly smoke. The experiment which counterbalanced the order of testing showed that in both test situations smoking produced a clear increase in heart rate (HR) and in skin conductance (SC); however, when testing was carried out in the home environment the increase in the HR was significantly less than in the laboratory. No significant differences were found for the baseline HR values in the two environments and there were no significant situational effects in the SC data. It was concluded that under conditions of normal smoking, data on the physiological effects of a cigarette in the laboratory may not be fully generalizable to those seen in the natural smoking situation. Several possible mechanisms of this situationally-specific effect of smoking were discussed.     

Repetitive exposure does not attenuate the sensory impact of the habituated stimulus.

Examined the hypothesis that habituation may reduce the perceived intensity of the repeated stimulus, using 12 naive male albino Holtzman rats. A brief electric shock that elicited a reflexive jump and inhibited a noise-induced startle reaction was tested for its eliciting and inhibiting potentials following a series of shock presentations in a habituation session. Repeated presentations of the shock stimulus diminished the elicited reaction but did not reduce its inhibitory effect on the acoustic startle reaction. This finding reveals that habituation does not affect functional stimulus intensity. It was also found that habituation training with the shock enhanced the reaction to a control acoustic stimulus, an indication of the nonspecific nature of sensitization. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Somatostatin does not attenuate intestinal injury in dextran sodium sulphate-induced subacute colitis

Forty-two patients with high-grade intramedullary osteosarcoma treated at Walter Reed Army Medical Center between 1985 and 1995 were reviewed to determine what effects military "managed health care" had on diagnosis, treatment, and outcome. Five-year survival was 61% overall (SE +/- 9.9%), despite local disease control obtained in 95% of patients. There was a statistically significant difference between active duty members and dependents in time to diagnosis (p = 0.008), yet there was no significant difference in survival between the two groups. Five-year survival in our patient population was slightly lower than 5-year survival reported in some large civilian medical centers despite good local disease control and intensive multiagent chemotherapy. Delays in diagnosis and military status had no apparent effect on survival, although limb salvage was not possible in nearly 40% of patients because of tumor size, disease extent, and involvement of neurovascular structures.     

Metoprolol does not attenuate atherosclerosis in lipid-fed rabbits exposed to environmental tobacco smoke

BACKGROUND: We previously demonstrated that exposure to environmental tobacco smoke (ETS) increases the development of atherosclerosis in lipid-fed rabbits. Clinical studies have suggested a protective effect of beta-blockers in smokers. Accordingly, we evaluated the effects of metoprolol in this animal model to see whether this beta-blocker would block the atherogenic effects of ETS. METHODS AND RESULTS: Thirty-two New Zealand White male rabbits on a 0.3% cholesterol diet were randomly divided into four groups: ETS-metoprolol (ETS-M), ETS-control (ETS-C), and non-ETS with metoprolol (NETS-M) and without metoprolol (NETS-C). The two metoprolol-treated groups received metoprolol at a dose of 0.4 mg.kg-1.h-1 administered subcutaneously by an osmotic pump. Rabbits in the ETS groups were exposed to sidestream smoke from four Marlboro cigarettes per 15 minutes, 6 hours a day, for 10 weeks. Average air carbon monoxide (CO), nicotine, and total particulates (TP) in the exposure chambers were 67.2 +/- 3.1 (SEM) ppm, 1133.7 +/- 78.4 micrograms/m3, and 37.7 +/- 3.0 mg/m3, respectively. Plasma nicotine was significantly higher in ETS-exposed rabbits than in nonexposed rabbits (7.1 +/- 1.9 versus 0.5 +/- 0.1 ng/mL, P < .01). Blood carbon monoxide hemoglobin (COHb) in the ETS-M group was significantly higher than that in the NETS-M group (4.0 +/- 0.2% versus 1.3 +/- 0.1%, P < .0001). The lipid lesions in the aorta and pulmonary artery were 57.2 +/- 7.6% and 33.1 +/- 6.4% (ETS-M), 62.8 +/- 8.4% and 58.4 +/- 6.1% (ETS-C), 38.7 +/- 9.4% and 24.8 +/- 7.7% (NETS-M), and 49.8 +/- 8.7% and 32.7 +/- 7.1% (NETS-C). There were significant differences in lipid deposits of the arteries between the controls and the ETS-exposed rabbits (37 +/- 1% versus 53 +/- 1%, P = .004) and between the controls and metoprolol-treated rabbits (51 +/- 1% versus 38 +/- 1%, P = .027). The benefit of metoprolol was independent of ETS exposure (ETS x metoprolol interaction, P = .595). CONCLUSIONS: Exposure to ETS significantly accelerated and metoprolol decreased the development of atherosclerosis in lipid-fed rabbits, but there was no interaction between the effects of ETS exposure and metoprolol. Metoprolol did not protect against the effects of ETS on atherosclerosis, suggesting that the beta-adrenergic system is not the mechanism of ETS-induced atherosclerosis.     

Hypotension does not alter the antinociceptive effect of nifedipine

We explored the relationship between antinociceptive and hypotensive effects of nifedipine (NIF) injected intraperitoneally ( ip, 15 mg/kg) and epidurally (epi, 20 microM), as compared to verapamil (VER, 10 mg/kg ip) and nitroglycerin (NTG, 0.1 and 0.15 mg/kg ip). The systolic blood pressure (BP) and tail-flick (TF) latencies were measured simultaneously every 10 min for 2 hours and individual values of both measurements were correlated. The highest antinociceptive as well as hypotensive effects were both measured in the group receiving NIF epi., with the correlation coefficient r2=0.2878. Injected ip., NIF revealed similar antinociceptive effect, whereas the other studied drugs were not effective. As to the degree of hypotensive activity, NIF epi was followed by VER, NTG 0.1, NIF ip. and NTG 0.15. No significant correlation was found between BP and TF latencies in any group receiving the drugs. We concluded that the antinociceptive response, measured by the tail-flick technique, is independent of the hypotensive activity of the studied drugs, including NIF.     

Attentional momentum does not underlie the inhibition of return effect.

J. Pratt, T. M. Spalek, and F. Bradshaw (1999) recently proposed that attentional momentum is the mechanism underlying the inhibition of return (IOR) effect. They suggested that momentum associated with an attentional movement away from a peripherally cued location and toward an uncued opposite location is essential and fundamental to the finding of an IOR effect. Although it is clear from the present study and from a reanalysis of data from Pratt et al. that response time can be facilitated at an uncued opposite location, this putative effect of attentional momentum is neither robust nor reliable. First, it occurs for only a minority of participants. Second, it occurs in only a subset of the cued display positions. And finally, it is uncorrelated with the occurrence of IOR. Together the data indicate that the attentional momentum hypothesis is an overgeneralization and that it does not underlie the robust and reliable IOR effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The 5-HT3 antagonist, BRL 46470 does not attenuate m-chlorophenylpiperazine (mCPP)-induced changes in human volunteers

Results from animal studies have suggested that serotonin (5-HT) antagonists acting on the 5-HT3 receptor may have anxiolytic properties. We have assessed whether pretreatment with the 5-HT3 receptor antagonist BRL 46470 (1 mg orally) attenuates the increase in anxiety induced in healthy volunteers by intravenous infusion of m-chlorophenylpiperazine (mCPP: 0.08 mg/kg over 2 min). In this double-blind placebo-controlled crossover study in 12 healthy men who were volunteers, infusion of mCPP caused significant increases in self-ratings for the psychological and physical symptoms of anxiety, for the symptoms of panic attack, and in the plasma levels of cortisol and prolactin, with four subjects (33%) experiencing an mCPP-induced "panic attack." Pretreatment with BRL 46470 did not attenuate any of these mCPP-induced changes. These results do not support suggestions from animal studies that 5-HT3 receptor antagonists can attenuate mCPP-induced anxiety, although it is conceivable that a different dose of BRL 46470 may have been effective.     

Revelation effect: Effort or priming does not create the sense of familiarity.

The revelation effect is the tendency to give higher proportions of positive responses to recognition test items that are distorted. Two plausible explanations of this response bias were tested. The 1st 3 experiments showed that the sense of familiarity leading to the revelation effect is not created because of the extra time or effort spent on the distorted items. The magnitude of the effect was neither correlated with the time taken to reveal the distorted items nor influenced by the Ss' efforts in revealing such items. The next 4 experiments showed that the sense of familiarity is not created because of priming of target words during the act of revealing. High-frequency words (presumed to be more highly associated to other words) and categorically or orthographically similar words did not elicit greater revelation effects than those elicited with low-frequency words and categorically or orthographically dissimilar words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The hypotensive effect of cisapride in rat

1. Cisapride is a prokinetic agent believed to facilitate acetylcholine release from the myenteric plexus of the gut. The aim of the present study was to investigate the effect of cisapride on blood pressure and the effects of muscarinic receptor antagonists on the cisapride-induced blood pressure changes. 2. Cisapride was given i.v. alone or 10 min after muscarinic receptor antagonists. Cisapride given i.v. produced a significant decrease in blood pressure in a dose-related manner. Atropine, AF-DX 116 and 4-DAMP given 10 min before cisapride injection, partially inhibited the hypotensive response to cisapride. In pithed rat, the effect of cisapride on blood pressure remained unaltered. 3. This study indicates that the action of cisapride is not through central mechanisms and part of cisapride's effect is through the cholinergic system.     

Beta-2-agonists are still of value. Tolerance does not affect the bronchodilating effect

Use of the potent bronchodilators, beta 2-adrenoceptor agonists, has been a cornerstone of the treatment of obstructive lung disease, especially asthma, for the past 30 years. However, the occurrence of side effects and the development of tolerance have been discussed as limitations to their use. beta 2-Adrenoceptors are located on the surface of most cell types throughout the human body, and treatment with beta 2-agonists may exert effects in a wide variety of tissues. As with other pharmacological receptors, beta 2-adrenoceptors in most tissues develop tolerance as a result of continuous beta 2-stimulation. However, the bronchodilatory effect appears to be unaffected by the development of tolerance. Interestingly, most studies have yielded evidence suggesting tolerance development regarding protection against bronchoconstrictor stimuli such as methacholine, adenosine and exercise. Although the protective effect of a beta 2-agonist becomes attenuated with continuous treatment, this tolerance is partial and adequate residual protective effect remains.     

Tibolone does not have a sustained measurable thermogenic effect in postmenopausal women

Evidence is presented suggesting hybridization in several species in the genus Ceratophyllus. Suspected interbreeding is reported as follows: C. idius x C. niger; C. celsus x C. scopulorum; C. celsus x C. petrochelidoni. The 1st of these was described as C. niger inflexus (Jordan, 1929). The 2nd was described as C. calderwoodi Holland, 1979, and the 3rd has been considered a dimorphic form of C. celsus (Holland 1985).     

Adventitial stripping does not strip the adventitia

This study investigates the process of stripping the adventitia off a blood vessel, which is a normal procedure prior to performing a microvascular anastomosis. In five rats, the common carotid and the superficial femoral arteries of one side were stripped sharply, whereas the arteries of the other side were left unstripped to serve as controls. In a further set of five rats, the arteries were stripped bluntly. Immediately following stripping, experimental and control arterial segments were removed. Histology of cross sections of the segments was studied. In no case was there complete removal of the adventitia. When stripped and control arterial sections were compared, no significant difference between cross-sectional adventitial areas could be demonstrated. Morphologic study revealed that stripping mainly removes large collagen fibers from the adventitia. The small collagen fibrils that are still in place fan out in such a way that although considerable tissue is removed, the volume that the adventitia occupies remains the same. Stripping the adventitia does not cause complete removal of the adventitia, and in this study no significant reduction in the adventitial volume could be found. Stripping does, however, allow a better view of the cut edge of the vessel wall under an operating microscope. Since blunt stripping could cause damage to other vessel wall layers, sharp stripping is to be preferred.     

Audiovisual bounce-inducing effect: Attention alone does not explain why the discs are bouncing.

Two discs moving from opposite points in space, overlapping and stopping at the other disc's starting point, can be seen as either bouncing or streaming through each other. With silent displays, observers report the discs as streaming, whereas if a sound is played when the discs touch each other, observers report the discs as bouncing. The origin of the switch from streaming to bouncing response is not known yet. The sound either shifts perception toward that of an impact-elastic event (i.e., a bounce) or subtracts the attention that is necessary to perceive the discs as streaming. We used either impact-similar (abrupt amplitude attack, gradual decay) or impact-dissimilar sounds (gradual amplitude attack, abrupt decay) and found that the first sounds induce the bouncing response, whereas the latter, although as distracting as the first, render streaming and bouncing responses equally frequent at most. We interpret the audiovisual bouncing effect as resulting from attention subtraction, which raises the number of bounce responses in comparison with silent displays, and from perception, which further increments the number of bounce responses and turns the response into a strong bounce response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eprosartan does not affect the pharmacodynamics of warfarin

The purpose of this study was to conduct a retrospective analysis of the clinical spectrum, treatment and morbidity of the patients who have suffered high tension electrical injuries with current passage through their body (59 patients). Voltage, localization and surgical treatment seem to be the main factors influencing the lesion and the morbidity. The following points were considered: (1) Is there any relation between known factors such as voltage and the localization of the points of contact with the incidence and the type of complications and sequelae? (2) Do the observations show that wound management and the excision of dead tissues is the most adequate? From factors studied in our patients (voltage, point of entry and pathway of current, associated multiple trauma or flame burns, surgical treatment) we have found that the voltage does not have any influence on the severity of the wound nor on the percentage of sequelae (cataracts, limb amputation, neurologic complications). The current pathway, as well as its points of entry, does not show any relation with the presence of renal failure, cardiac arrhythmia and cataracts. A clear relationship between the point of entry of the current and the appearance of neurologic injury with presence of paralysis and permanent regional anaesthesia at the same level was observed. The presence of associated burns was not related to any other complications or sequelae. For those patients whose length of contact has been shorter we find a lower rate of amputations despite having associated limb fractures. Fasciotomy incisions appear to confer benefit as this series shows that this procedure decreases the rate of limb amputations.     

The subliminal mere exposure effect does not generalize to structurally related stimuli.

R. F. Bornstein (1994) questioned whether subliminal mere exposure effects might generalize to structurally related stimuli, thereby providing evidence for the existence of implicit learning. Two experiments examined this claim using letter string stimuli constructed according to the rules of an artificial grammar. Experiment 1 demonstrated that brief, masked exposure to grammatical strings impaired recognition but failed to produce a mere exposure effect on novel structurally related strings seen at test. Experiment 2 replicated this result but also demonstrated that a reliable mere exposure effect could be obtained, provided the same grammatical strings were presented at test. The results suggest that the structural relationship between training and test items prevents the mere exposure effect when participants are unaware of the exposure status of stimuli, and therefore provide no evidence for the existence of implicit learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sulfhydryl group donors potentiate the hypotensive effect of acetylcholine in rats

Nitric oxide mediates the vasodilator and hypotensive responses of acetylcholine infusion. It has been reported that nitric oxide could be protected from free radical destruction by forming an S-nitrosothiol compound. Furthermore, sulfhydryl donors such as N-acetylcysteine or thiosalicylic acid enhance nitric oxide production from nitroglycerin. Consequently, the hypotensive effect of intravenous acetylcholine infusion might be potentiated during the simultaneous administration of sulfhydryl donors. The objective of the present study was to test in Okamoto spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats (1) whether the hypotensive effect of acetylcholine (10 micrograms/kg per minute) was affected by the simultaneous administration of N-acetylcysteine (10 micrograms/kg per minute) or thiosalicylic acid (10 micrograms/kg per minute), and (2) whether NG-nitro-L-arginine-methyl ester (100 micrograms/kg per minute) administration was able to reverse the changes induced by acetylcholine plus N-acetylcysteine or acetylcholine plus thiosalicylic acid. The administration of acetylcholine reduced (P < .05) mean arterial pressure in WKY rats (13 +/- 2%) and SHR (14 +/- 2%) without affecting urine flow rate, urinary sodium excretion, and glomerular filtration rate. In the presence of N-acetylcysteine, the acetylcholine-induced reduction in mean arterial pressure was potentiated (P < .05) in WKY rats (24 +/- 4%) and SHR (20 +/- 2%). These changes in mean arterial pressure were accompanied by significant reductions in urine flow rate and urinary sodium excretion in WKY rats, as well as in glomerular filtration rate in SHR.2     

Blockade of digestion by famotidine pretreatment does not interfere with the opioid-enhancing effect of ingested amniotic fluid

Ingestion of placenta or amniotic fluid by rats has been shown to enhance ongoing opioid-mediated antinociception, but does not, by itself, produce antinociception. This enhancement is produced by an active substance(s) in placenta and amniotic fluid that we have termed POEF for placental opioid-enhancing factor. Previous research has shown that enhancement requires mediation by the gastrointestinal system: gastric vagotomy blocks enhancement produced by ingested placenta; amniotic fluid injected SC or IP does not produce enhancement. The present study was designed to distinguish between two possible explanations for the blockade of the POEF effect produced by gastric vagotomy: that afferent information arising in vagal gastric receptors conveys the critical information to the CNS, or that disruption of vagal efferent action on digestion blocks the manufacture or activation of the POEF molecule in the gut. Famotidine is an H2-histamine receptor antagonist that reduces gastric acid and pepsin secretion to an extent at least as great as gastric vagotomy. Rats treated with either famotidine or a vehicle were fed placenta or a control substance, then stimulated with vaginal/cervical probing to produce antinociception that is partly opioid mediated. Famotidine did not block POEF enhancement of vaginal/cervical stimulation-induced analgesia in a tail flick latency test. These results suggest that enhancement by POEF does not require normal digestive processes or other processes inhibited by famotidine.