Brief Exposure (brief + exposure)

Distribution by Scientific Domains


Selected Abstracts


BRIEF EXPOSURE TO ETHANOL AUGMENTS VASCULAR CONTRACTILITY IN HUMAN CHORIONIC PLATE ARTERIES

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2004
Eun Hui Hong
Summary 1.,Heavy alcohol consumption has been known as a risk factor for hypertension, although the mechanism by which alcohol intake causes hypertension remains elusive. 2.,We tested the hypothesis that brief exposure to ethanol augments vascular contractility through the stress response in human chorionic plate arteries. 3.,Human chorionic plate arteries were mounted in organ baths and exposed to 5% ethanol for 15, 30 or 45 min. 4.,Brief exposure for 45 min, but not 15 min, not only augmented contractility to KCl and 5-hydroxytryptamine 5 h after the end of exposure, but also increased the expression of heat shock protein (HSP) 70 in the tissues. 5.,Reverse transcription,polymerase chain reaction showed gradual increases of hsp70 mRNA expression, but not heat shock cognate 70 (hsc70), hsp90, or glucose regulatory protein 78 (grp78) mRNA expression, in an exposure time-dependent manner 3 h after the end of exposure. 6.,These results indicate that ethanol augments vascular contractility through the stress response. [source]


Brief exposure to the biological mother "potentiates" the isolation behavior of precocial Guinea pig pups

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 8 2006
Michael B. Hennessy
Abstract When isolated rat pups are briefly reunited with a lactating female, her subsequent removal leads to a dramatic increase in the emission of ultrasonic vocalizations, but not other behaviors. Whether this socially induced augmentation of isolation behavior (i.e., "potentiation") is characteristic only of altricial rodents is not known. Therefore, we examined precocial guinea pig pups in a potentiation paradigm. Ten-day-old guinea pigs were isolated in a test cage for 10 min, at which time they were then placed into a second cage for 5 min that either contained a companion or, for controls, was empty. Pups were then isolated again in the test cage for a second 10-min period. Control pups showed a significant reduction in vocalizing and locomotor activity from the first to second isolation period. Exposure to the biological mother prevented the decline in both behaviors (Experiment 1), whereas exposure to a familiar littermate (Experiment 2) had no effect, and exposure to an unfamiliar lactating female (Experiment 3) had only a minimal effect on locomotor activity. The results show that potentiation of isolation behaviors is not limited to altricial rodents, and suggest that specific characteristics of the effect (i.e., its magnitude, the specific behaviors affected, and the selectivity of the response to particular social partners) varies with the abilities and requirements of the young, as well as the behavioral ecology of the species in question. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 48: 653,659, 2006. [source]


MDMA, methamphetamine and their combination: possible lessons for party drug users from recent preclinical research

DRUG AND ALCOHOL REVIEW, Issue 1 2007
KELLY J. CLEMENS
Abstract The substituted amphetamines 3,4-methylenedioxymethamphetamine (MDMA, ,Ecstasy') and methamphetamine (METH, ,ice', ,speed') are increasingly popular drugs amongst party-drug users. Studies with humans have investigated the acute and possible long-term adverse effects of these drugs, yet outcomes of such studies are often ambiguous due to a variety of confounding factors. Studies employing animal models have value in determining the acute and long-term effects of MDMA and METH on brain and behaviour. Self-administration studies show that intravenous METH is a particularly potent reinforcer in rats and other species. In contrast, MDMA appears to have powerful effects in enhancing social behaviour in laboratory animals. Brief exposure to MDMA or METH may produce long-term reductions in dopamine, serotonin and noradrenaline in the brain and alterations in the density of various receptor and transporter proteins. However it is still unclear, particularly in the case of MDMA, whether this reflects a ,neurotoxic' effect of the drug. Lasting alterations in social behaviour, anxiety, depressive symptoms and memory have been demonstrated in laboratory rats given MDMA or METH and this matches long-term changes reported in some human studies. Recent laboratory studies suggest that MDMA/METH combinations may produce greater adverse neurochemical and behavioural effects than either drug alone. This is of some concern given recent evidence that party drug users may be frequently exposed to this combination of drugs. [source]


Longer-term implications of responsiveness to ,thin-ideal' television: support for a cumulative hypothesis of body image disturbance?

EUROPEAN EATING DISORDERS REVIEW, Issue 6 2003
Duane Hargreaves
Brief exposure to thin-ideal media images has been shown to have a small but consistent negative impact on women and girls' body dissatisfaction. The present study aimed to examine the consequence of these small changes in body dissatisfaction for the development of body image over time. A sample of 80 adolescents (mean age,=,17.2 years) completed measures of body dissatisfaction, drive for thinness, and drive for muscularity. Two years earlier they had viewed either 20 appearance-related television commercials (containing female thin ideals) or 20 non-appearance commercials as part of an experimental study. For girls, initial body dissatisfaction change in response to viewing appearance commercials at time 1 predicted subsequent body dissatisfaction and drive for thinness 2 years later, above and beyond the variance predicted by initial body dissatisfaction. Similar results were observed for boys' drive for thinness but not for body dissatisfaction. Overall, these results are consistent with a cumulative hypothesis of media exposure and body image development. Copyright © 2003 John Wiley & Sons, Ltd and Eating Disorders Association. [source]


Brief exposure to NMDA produces long-term protection of cerebellar granule cells from apoptosis

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2005
Xavier Xifro
Abstract Cerebellar granule cells (CGCs) require excitatory inputs to survive during their postnatal migration from the external to the internal granule cell layers. The lack of innervation of mossy fibres induces CGC death by apoptosis. In vitro, CGCs die by apoptosis in the presence of physiological concentrations of KCl (5 mm or K5) but they survive in the presence of depolarizing concentrations of KCl (25 mm or K25) or N -methyl- d -aspartate (NMDA) by a mechanism dependent on calcium influx. The addition of NMDA or K25, for only 24 h, to immature CGCs cultures [2 days in vitro (DIV)] was able to produce a remarkable and long-term protection until 8 DIV. Moreover, our data show that NMDA and K25-mediated long-lasting protection was related to an inhibition of caspase-3 activity. By using different protein kinase inhibitors, we have shown that the inhibition of caspase-3 activation by NMDA was dependent on the activation of tyrosine kinases and phosphatidylinositol 3-kinase (PI3-kinase). Moreover, an impairment in NMDA-mediated neuroprotection and caspase-3 inhibition was observed when the action of brain-derived neurotrophic factor (BDNF) was blocked. By contrast, K25-mediated neuroprotection was BDNF-independent and was mediated by a mitogen-activated protein kinase- and PI3-kinase-dependent inhibition of caspase-3. [source]


Insensitivity to glutamate neurotoxicity mediated by NMDA receptors in association with delayed mitochondrial membrane potential disruption in cultured rat cortical neurons

JOURNAL OF NEUROCHEMISTRY, Issue 5 2008
Yuki Kambe
Abstract We have attempted to elucidate mechanisms underlying differential vulnerability to glutamate (Glu) using cultured neurons prepared from discrete structures of embryonic rat brains. Brief exposure to Glu led to a significant decrease in the mitochondrial activity in hippocampal neurons cultured for 9 or 12 days at 10 ,M to 1 mM with an apoptosis-like profile, without markedly affecting that in cortical neurons. Brief exposure to Glu also increased lactate dehydrogenase release along with a marked decrease in the number of cells immunoreactive for a neuronal marker protein in hippocampal, but not cortical, neurons. Similar insensitivity was seen to the cytotoxicity by NMDA, but not to that by tunicamycin, 2,4-dinitrophenol, hydrogen peroxide or A23187, in cortical neurons. However, NMDA was more efficient in increasing intracellular free Ca2+ levels in cortical neurons than in hippocampal neurons. Antagonists for neuroprotective metabotropic Glu receptors failed to significantly affect the insensitivity to Glu, while NMDA was more effective in disrupting mitochondrial membrane potentials in hippocampal than cortical neurons. These results suggest that cortical neurons would be insensitive to the apoptotic neurotoxicity mediated by NMDA receptors through a mechanism related to mitochondrial membrane potentials, rather than intracellular free Ca2+ levels, in the rat brain. [source]


Alcohol-Induced Up-Regulation of Fibrinolytic Activity and Plasminogen Activators in Human Monocytes

ALCOHOLISM, Issue 8 2002
Edlue M. Tabengwa
Background Moderate alcohol consumption is associated with reduced risk for coronary heart disease. This may due, in part to increased fibrinolysis. Monocytes synthesize fibrinolytic proteins, tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA), and their receptors. These studies were carried out to determine the effect of low alcohol on monocyte fibrinolytic activity and PA messenger RNA (mRNA) synthesis. Methods Peripheral blood monocytes and U937 cells were incubated in absence/presence of low alcohol (0.1%, v/v) for various times (0,1 hr), followed by incubations in the absence of alcohol (0,24 hr) before measurement of fibrinolytic activity and PA mRNA levels (reverse transcriptase polymerase chain reaction). Results Brief exposure (15 min, 4°C) of U937 cells to low alcohol resulted in an approximately 2- to 3-fold increase (269.0 ± 5.6 fmol/1 × 106 cells versus 656.0 ± 94.0 fmol/1 × 106 cells) in fibrinolytic activity. Preincubation of U937 cells and peripheral blood monocytes in low alcohol (1 hr, 37°C) followed by incubation in the absence of alcohol (24 hr) resulted in a sustained approximately 4- to 5-fold increase (414.0 ± 174.7 vs. 965.33.0 ± 104.8 fmol/1 × 106 cells) and an approximately 3- to 4-fold (20.5 ± 2.14 vs. 74 ± 2.28 fmol/2 × 106 cells, respectively) increase in fibrinolytic activity. Preincubation of monocytes with low alcohol (1 hr, 37°C) followed by incubation in the absence of alcohol (6 hr) resulted in an approximately 5- to 6-fold (0.06 ± 0.02 vs. 0.42 ± 0.02) and an approximately 2- to 3-fold (0.89 ± 0.04 vs. 2.07 ± 0.29) increase in t-PA and u-PA mRNA (reverse transcriptase polymerase chain reaction; PA/glyceraldehyde-3-phosphate dehydrogenase ratio), respectively. Conclusions These data suggest that low alcohol exerts a rapid, direct, and sustained effect on monocyte fibrinolytic activity, which may be, due in part, to increased monocyte t-PA/u-PA expression. These data provide a feasible molecular mechanism by which alcohol effects on monocyte fibrinolysis may contribute to the cardioprotective benefit associated with moderate alcohol consumption. [source]


Brief exposure to a 50 Hz, 100 ,T magnetic field: Effects on reaction time, accuracy, and recognition memory

BIOELECTROMAGNETICS, Issue 3 2002
John Podd
Abstract The present study investigated both the direct and delayed effects of a 50 Hz, 100 ,T magnetic field on human performance. Eighty subjects completed a visual duration discrimination task, half being exposed to the field and the other half sham exposed. The delayed effects of this field were also examined in a recognition memory task that followed immediately upon completion of the discrimination task, Unlike our earlier studies, we were unable to find any effects of the field on reaction time and accuracy in the visual discrimination task. However, the field had a delayed effect on memory, producing a decrement in recognition accuracy. We conclude that after many years of experimentation, finding a set of magnetic field parameters and human performance measures that reliably yield magnetic field effects is proving elusive. Yet the large number of significant findings suggests that further research is warranted. Bioelectromagnetics 23:189,195, 2002. © 2002 Wiley-Liss, Inc. [source]


BRIEF EXPOSURE TO ETHANOL AUGMENTS VASCULAR CONTRACTILITY IN HUMAN CHORIONIC PLATE ARTERIES

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2004
Eun Hui Hong
Summary 1.,Heavy alcohol consumption has been known as a risk factor for hypertension, although the mechanism by which alcohol intake causes hypertension remains elusive. 2.,We tested the hypothesis that brief exposure to ethanol augments vascular contractility through the stress response in human chorionic plate arteries. 3.,Human chorionic plate arteries were mounted in organ baths and exposed to 5% ethanol for 15, 30 or 45 min. 4.,Brief exposure for 45 min, but not 15 min, not only augmented contractility to KCl and 5-hydroxytryptamine 5 h after the end of exposure, but also increased the expression of heat shock protein (HSP) 70 in the tissues. 5.,Reverse transcription,polymerase chain reaction showed gradual increases of hsp70 mRNA expression, but not heat shock cognate 70 (hsc70), hsp90, or glucose regulatory protein 78 (grp78) mRNA expression, in an exposure time-dependent manner 3 h after the end of exposure. 6.,These results indicate that ethanol augments vascular contractility through the stress response. [source]


Human airway trypsin-like protease induces amphiregulin release through a mechanism involving protease-activated receptor-2-mediated ERK activation and TNF ,-converting enzyme activity in airway epithelial cells

FEBS JOURNAL, Issue 24 2005
Manabu Chokki
Human airway trypsin-like protease (HAT), a serine protease found in the sputum of patients with chronic airway diseases, is an agonist of protease-activated receptor-2 (PAR-2). Previous results have shown that HAT enhances the release of amphiregulin (AR); further, it causes MUC5AC gene expression through the AR-epidermal growth factor receptor pathway in the airway epithelial cell line NCI-H292. In this study, the mechanisms by which HAT-induced AR release can occur were investigated. HAT-induced AR gene expression was mediated by extracellular signal-regulated kinase (ERK) pathway, as pretreatment of cells with ERK pathway inhibitor eliminated the effect of HAT on AR mRNA. Both HAT and PAR-2 agonist peptide (PAR-2 AP) induced ERK phosphorylation; further, desensitization of PAR-2 with a brief exposure of cells to PAR-2 AP resulted in inhibition of HAT-induced ERK phosphorylation, suggesting that HAT activates ERK through PAR-2. Moreover, PAR-2 AP induced AR gene expression subsequent to protein production in the cellular fraction through the ERK pathway indicating that PAR-2-mediated activation of ERK is essential for HAT-induced AR production. However, in contrast to HAT, PAR-2 AP could not cause AR release into extracellular space; it appears that activation of PAR-2 is not sufficient for HAT-induced AR release. Finally, HAT-induced AR release was eliminated by blockade of tumour necrosis factor ,-converting enzyme (TACE) by the TAPI-1 and RNA interference, suggesting that TACE activity is necessary for HAT-induced AR release. These observations show that HAT induces AR production through the PAR-2 mediated ERK pathway, and then causes AR release by a TACE-dependent mechanism. [source]


Familial aquagenic acrokeratoderma: case reports and review of the literature

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2005
Yasemin Saray MD
In recent years, a number of authors have described the development of palmar or palmoplantar keratoderma after brief exposure to water. Herein, we report a father and son with this condition, which we prefer to call aquagenic acrokeratoderma. These cases are interesting because they mark the first documentation of this entity in males. Also, they provide further evidence of familial occurrence. [source]


THE ROLE OF CALCIUM IN FLOW-STIMULATED BIOLUMINESCENCE OF THE RED TIDE DINOFLAGELLATE LINGULODINIUM POLYEDRUM

JOURNAL OF PHYCOLOGY, Issue 2000
P. Von Dassow
Many marine planktonic dinoflagellates emit flashes of light in response to either laminar or turbulent flows as well as direct mechanical stimulation. The production of a flash of light is known to be mediated by a proton-mediated action potential across the vacuolar membrane; the mechanotransduction process initiating this action potential is unknown. Here we report on an investigation into the role of Ca+2 in the mechanotransduction process regulating bioluminescence in the red tide dinoflagellate Lingulodinium polyedrum. Calcium ionophores and low concentrations of the membrane-disrupting agent digitonin stimulated bioluminescence only when calcium was present in the media or added with the agent, indicating that the flash-triggering vacuolar action potential is specifically stimulated by a calcium influx. A variety of known calcium channel blockers or antagonists inhibited mechanically stimulated bioluminescence but did not affect cellular bioluminescent capacity. In many cases the inhibitory affect occurred after only a brief exposure. In addition, gadolinium (Gd+3), a blocker of many stretch-activated ion channels, caused potent inhibition of mechanically stimulated bioluminescence. The order of potency of the transition metals tested was La+3 > Gd+3 > Co+2 > Mn+2 > Ni+2, similar to their potency as blockers of known calcium channels. Experiments with a quantified shear flow demonstrated that flow-stimulated bioluminescence depended on the level of extracellular calcium. Future work will elucidate the signaling pathway involving calcium-mediated flow-stimulated mechanotransduction. Our goal is to use bioluminescence as a proxy for the initial cellular mechanotransduction events triggered by fluid flow. [source]


Effects of meiosis-inhibiting agents and equine chorionic gonadotropin on nuclear maturation of canine oocytes

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 4 2003
N. Songsasen
Abstract Experiments were conducted to determine the effects of meiosis-inhibiting-agents and gonadotropins on nuclear maturation of canine oocytes. The culture medium was TCM199,+,10 ng/ml epidermal growth factor supplemented with 25 ,M ,-mercaptoethanol, 0.25 mM pyruvate, and 1.0 mM L-glutamine (Basal TCM). Initially, oocytes were cultured in Basal TCM alone or in Basal TCM,+,dibutylryl cyclic adenosine monophosphate (0.5, 1, 5, or 10 mM dbcAMP) for 24 hr. Dibutylryl cAMP inhibited resumption of meiosis in a dose-dependent manner; 60% of oocytes remained at the germinal vesicle (GV) stage after being cultured for 24 hr in 5 mM dbcAMP. The meiosis-inhibitory effect of dbcAMP appeared to be reversible, as the oocytes resumed meiosis and completed nuclear maturation after being cultured for an additional 48 hr in its absence. Oocytes were then cultured in Basal TCM alone or in Basal TCM,+,roscovitine (12.5, 25, or 50 ,M) for 24 hr. Although ,60% of oocytes cultured in 25 ,M roscovitine remained at the GV stage, this percentage was not significantly different from the 48% that also remained at the GV stage when cultured in its absence. Oocytes were cultured in Basal TCM,+ 25 ,M roscovitine for 17 hr, exposed briefly to equine chorionic gonadotropin (eCG), and then cultured in Basal TCM for 48 hr. Short exposure of oocytes to eCG was beneficial, as it significantly increased the proportion of oocytes developing beyond germinal vesicle breakdown (P,<,0.05) with ,20,30% of these were metaphase I (MI) oocytes. Study of the kinetics of nuclear maturation demonstrated that large numbers of oocytes remained at MI even after being cultured for 52 hr following brief exposure to eCG. This study showed that in vitro maturation of canine oocytes can be somewhat improved by short exposure of oocytes to eCG. However, further studies are still required to derive effective methods to mature canine oocytes in vitro. Mol. Reprod. Dev. 65: 435,445, 2003. © 2003 Wiley-Liss, Inc. [source]


Persistent generalized anxiety after brief exposure to the dopamine antagonist metoclopramide

PSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 2 2007
MICHAEL KLUGE md
Abstract The authors describe a 31-year-old woman who developed persistent generalized anxiety after brief exposure to the dopamine antagonist metoclopramide. Independently of that, she had experienced a panic attack followed by dystonias, shortly after a single dose of that drug, 17 years before. Both temporal association and recurrence of anxiety symptoms after re-challenge with metoclopramide suggest a causal relationship. The case might provide an initial piece of evidence that dopaminergic neurotransmission can be involved in the pathogenesis of generalized anxiety disorder. [source]


The reverse-caricature effect revisited: Familiarization with frontal facial caricatures improves veridical face recognition

APPLIED COGNITIVE PSYCHOLOGY, Issue 5 2009
Jobany Rodríguez
Prior research suggests that recognition of a person's face can be facilitated by exaggerating the distinctive features of the face during training. We tested if this ,reverse-caricature effect' would be robust to procedural variations that created more difficult learning environments. Specifically, we examined whether the effect would emerge with frontal rather than three-quarter views, after very brief exposure to caricatures during the learning phase and after modest rotations of faces during the recognition phase. Results indicate that, even under these difficult training conditions, people are more accurate at recognizing unaltered faces if they are first familiarized with caricatures of the faces, rather than with the unaltered faces. These findings support the development of new training methods to improve face recognition. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Hemolymph ecdysteroids during the last three molt cycles of the blue crab, Callinectes sapidus: quantitative and qualitative analyses and regulation

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
J. Sook Chung
Abstract The profiles of circulating ecdysteroids during the three molt cycles prior to adulthood were monitored from the juvenile blue crab, Callinectes sapidus. Ecdysteroid patterns are remarkably similar in terms of peak concentrations ranging between 210,330,ng/ml hemolymph. Analysis of hemolymph at late premolt stage revealed six different types of ecdysteroids with ponasterone A (PoA) and 20-OH ecdysone (20-OH E) as the major forms. This ecdysteroid profile was consistent in all three molt cycles. Bilateral eyestalk ablation (EA) is a procedure that removes inhibitory neurohormones including crustacean hyperglycemic hormone (CHH) and molt-inhibiting hormone (MIH) and often results in precocious molting in crustaceans. However, the inhibitory roles of these neuropeptides in vivo have not yet been tested in C. sapidus. We determined the regulatory roles of CHH and MIH in the circulating ecdysteroid from ablated animals through daily injection. A daily administration of purified native CHH and MIH at physiological concentration maintained intermolt levels of ecdysteroids in the EA animals. This suggests that Y organs (YO) require a brief exposure to CHH and MIH in order to maintain the low level of ecdysteroids. Compared to intact animals, the EA crabs did not exhibit the level of peak ecdysteroids, and the major ecdysteroid turned out to be 20-OH E, not PoA. These results further underscore the important actions of MIH and CHH in ecdysteroidogenesis, as they not only inhibit, but also control the composition of output of the YO activity. © 2009 Wiley Periodicals, Inc. [source]


No effect of TETRA hand portable transmission signals on human cognitive function and symptoms

BIOELECTROMAGNETICS, Issue 5 2010
Ingunn S. Riddervold
Abstract Current radio frequency radiation exposure guidelines rest on well-established thermal effects. However, recent research into analogue and digital transmission fields at levels covered by the exposure guidelines has indicated possible detrimental effects on human cognitive performance. To investigate this, we conducted a controlled climate chamber study of possible changes in cognitive performance in healthy volunteers exposed to transmission signals from TETRA hand portables (TETRA handsets). The trial deployed a balanced, randomized, double-blinded cross-over design. Performance on different paper-and-pencil, auditory and computer-based cognitive tasks was monitored in 53 male volunteers (mean age 36.41 years, SD 8.35) during 45-min exposure to a TETRA handset and sham control signals remotely controlled from a laboratory more than 100,km away. The main cognitive outcome was the Trail Making B (TMB) test. In addition, the participants completed a computer-based questionnaire measuring self-reported psychological and physical symptoms. No statistically significant differences (P,<,0.05) between the TETRA and sham conditions were found for either TMB (estimated difference 3.8%, confidence interval (CI) ,1.6% to 9.2%) or any of the remaining cognitive tasks or symptoms. In conclusion, we found no evidence that brief exposure to hand-held TETRA transmitters' affects human cognitive function or subjective symptoms. Bioelectromagnetics 31:380,390, 2010. © 2010 Wiley-Liss, Inc. [source]


Expression of the CXCR6 on polymorphonuclear neutrophils in pancreatic carcinoma and in acute, localized bacterial infections

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 2 2008
M. M. Gaida
Summary The chemokine receptor CXCR6 has been described on lymphoid cells and is thought to participate in the homing of activated T-cells to non-lymphoid tissue. We now provide evidence that the chemokine receptor CXCR6 is also expressed by activated polymorphonuclear neutrophils (PMN) in vivo: Examination of biopsies derived from patients with pancreatic carcinoma by confocal laser scan microscopy revealed a massive infiltration of PMN that expressed CXCR6, while PMN of the peripheral blood of these patients did not. To answer the question whether CXCR6 expression is a property of infiltrated and activated PMN, leucocytes were collected from patients with localized soft tissue infections in the course of the wound debridement. By cytofluorometry, the majority of these cells were identified as PMN. Up to 50% of these PMN were also positive for CXCR6. Again, PMN from the peripheral blood of these patients were nearly negative for CXCR6, as were PMN of healthy donors. In a series of in vitro experiments, up-regulation of CXCR6 on PMN of healthy donors by a variety of cytokines was tested. So far, a minor, although reproducible, effect of tumour necrosis factor (TNF,) was seen: brief exposure with low-dose TNF, induced expression of CXCR6 on the surface of PMN. Furthermore, we could show an increased migration of PMN induced by the axis CXCL16 and CXCR6. In summary, our data provide evidence that CXCR6 is not constitutively expressed on PMN, but is up-regulated under inflammatory conditions and mediates migration of CXCR6-positive PMN. [source]


BRIEF EXPOSURE TO ETHANOL AUGMENTS VASCULAR CONTRACTILITY IN HUMAN CHORIONIC PLATE ARTERIES

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2004
Eun Hui Hong
Summary 1.,Heavy alcohol consumption has been known as a risk factor for hypertension, although the mechanism by which alcohol intake causes hypertension remains elusive. 2.,We tested the hypothesis that brief exposure to ethanol augments vascular contractility through the stress response in human chorionic plate arteries. 3.,Human chorionic plate arteries were mounted in organ baths and exposed to 5% ethanol for 15, 30 or 45 min. 4.,Brief exposure for 45 min, but not 15 min, not only augmented contractility to KCl and 5-hydroxytryptamine 5 h after the end of exposure, but also increased the expression of heat shock protein (HSP) 70 in the tissues. 5.,Reverse transcription,polymerase chain reaction showed gradual increases of hsp70 mRNA expression, but not heat shock cognate 70 (hsc70), hsp90, or glucose regulatory protein 78 (grp78) mRNA expression, in an exposure time-dependent manner 3 h after the end of exposure. 6.,These results indicate that ethanol augments vascular contractility through the stress response. [source]


Cardiac baroreflex control in humans during and immediately after brief exposure to simulated high altitude

CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2002
Frédéric Roche
Summary To examine the baroreflex response in humans during and immediately after acute hypoxia exposure, the cardiac baroreflex sensitivity (BRS) was studied using adaptation of RR intervals in response to spontaneous systolic blood pressure fluctuations (sequences methodology) in 11 unacclimatized subjects. All measurements were made under fixed breathing rate, and realized consecutively at baseline level (20 min), at an inspired oxygen concentration of 11% (15 min) and again under normoxic conditions (20 min; recovery period). The spontaneous baroreflex response decreases progressively during hypoxic exposure, causing a tachycardic response at this FiO2 without any significant alteration of the systolic or diastolic blood pressure. The magnitude of decrease for this variable at the end of exposure averaged 42·9 ± 15·6%. The simultaneous spectral analysis of heart rate (HR) variability in hypoxic condition confirmed an alteration in the parasympathetic activity (HFnu: ,17·8 ± 30·9% versus basal conditions, P<0·01) counterbalanced by an exaggerated sympathetic activity (LFnu: +33 ± 42·4%, P<0·05) at the sinus node. Interestingly, we could observe an enhanced cardiac baroreflex response during the period following the inhalation of the hypoxic mixture (+130·6 ± 15·6% of basal conditions, P<0·001). There is a relationship with a significant and abrupt increase in the parasympathetic control of HR (mean HR reached 111 ± 8·1% of the mean basal HR, P<0·01). These results suggest that brief exposure to hypoxia under rate-controlled ventilation is associated with a significant alteration in the spontaneous cardiac baroreflex. This important cardiac autonomic imbalance is followed by a significant increase in the cardiac parasympathetic drive even after the disappearance of the hypoxic stimulus. [source]


Survival of spores of Rhizopus stolonifer, Aspergillus niger, Botrytis cinerea and Alternaria alternata after exposure to ethanol solutions at various temperatures

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004
F. Mlikota Gabler
Abstract Aims:, To quantify and model the toxicity of brief exposures of spores of Rhizopus stolonifer, Aspergillus niger, Botrytis cinerea and Alternaria alternata to heated, aqueous ethanol solutions. These fungi are common postharvest decay pathogens of fresh grapes and other produce. Sanitation of produce reduces postharvest losses caused by these and other pathogens. Methods and Results:, Spores of the fungi were exposed to solutions containing up to 30% (v/v) ethanol at 25,50°C for 30 s, then their survival was determined by germination on semisolid media. Logistical, second-order surface-response models were prepared for each fungus. Subinhibitory ethanol concentrations at ambient temperatures became inhibitory when heated at temperatures much lower than those that cause thermal destruction of the spores by water alone. At 40°C, the estimated ethanol concentrations that inhibited the germination of 50% (LD50) of the spores of B. cinerea, A. alternata, A. niger and R. stolonifer were 9·7, 13·5, 19·6 and 20·6%, respectively. Conclusions:, Ethanol and heat combinations were synergistic. Control of spores of these fungi could be accomplished with much lower temperatures and ethanol concentrations when combined compared with either used alone. Botrytis cinerea and A. alternata were less resistant to the combination than A. niger or R. stolonifer. [source]


The effect of short-term low-temperature treatments on gene expression in Arabidopsis correlates with changes in intracellular Ca2+ levels

PLANT CELL & ENVIRONMENT, Issue 4 2003
K. NORDIN HENRIKSSON
ABSTRACT The role of changes in intracellular calcium ion concentration ([Ca2+]i) in low-temperature signal transduction in plants has lately been supported by several studies. An analysis to determine whether the low-temperature-induced increase in cytosolic Ca2+ concentration ([Ca2+]cyt) could be correlated with a downstream response such as gene expression was carried out. The induction of the low-temperature-regulated gene LTI78 was used as an end point marker of the signal transduction pathway. It was found that this gene is induced by very brief low-temperature exposures and that the induction does not depend on a continuous exposure to low temperature. By altering the cooling rate, different patterns of the Ca2+ response were obtained which could be correlated with different patterns of LTI78 induction. Furthermore, reducing the Ca2+ transients by pre-treatment with the Ca2+ channel blocker La3+ also led to a reduced level of gene induction. The results show that brief exposures to low temperature results in the onset of a signalling pathway that leads to the induction of gene expression. This indicates the involvement of changes in [Ca2+]cyt in low-temperature signalling leading to LTI78 expression but the presence of multiple signalling pathways is suggested. [source]