Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STRESS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2004

Self-reported stress reactivity and psoriasis-related stress of Nordic psoriasis sufferers.

OBJECTIVES: The purpose of the study was to investigate the perceived influence of stress on psoriasis onset and disease severity in a large sample of psoriatics and to compare stress reactors and non-reactors with respect to psoriasis-related stress, disease severity, family history of psoriasis and sociodemographic factors. PATIENTS/METHODS: A total of 5795 members of the Nordic psoriasis associations and 702 patients recruited from Nordic dermatologists or university clinics were asked whether their first outbreak of psoriasis occurred during times of worry and stress. They were also asked to rate the degree to which their psoriasis was influenced by stress and to complete the Psoriasis Life Stress Index, the Psoriasis Disability Index and a number of additional questions concerning sociodemographic factors. RESULTS: Seventy-one per cent of the members and 66% of the patients reported that their psoriasis was exacerbated by stress, and 35% in both groups reported that the onset of their psoriasis occurred during a time of worry and stress. Stress reactors, scoring above the median on stress reactivity, reported greater disease severity, psoriasis-related stress and impairment of disease-related quality of life. They also reported more frequent use of tobacco, tranquillizers and antidepressants. More women than men were stress reactors, and stress reactors were more likely to have a family history of psoriasis. CONCLUSION: Our findings confirm and extend the results of previous studies and indicate that a subgroup of psoriatics may be more psychologically reactive to their disease and its influence on everyday life. Whether this group is also physiologically more reactive to psychosocial stress remains to be investigated.

Analysis of Variance↗
PubMed1988

[The method for stress assessment of workers (Part 1). Stress score by self-rating method].

In order to evaluate the grade of reaction to stressors, especially those on occupational life of workers, the following stress survey was conducted. Eighteen new items of occupational life stressors were proposed in addition to the social readjustment rating scale (S.R.R.S.) prepared by Holmes. Furthermore, two items, "own stress tolerance" and "own stress at present," were designed in addition to the foregoing 65 stressors. Marriage is given a score of 50 in reference-standard of stress strength. These 67 items of 1,630 workers were evaluated by the self-rating method ranging in score from 0 to 100. The results can be summarized as follows: 1. As for each item, we examined the average value of the total sample and analyzed them by sex, age, kind of occupation, position, and length of service. We named these stress scores and analyzed the ranking of 65 stress scores. The item with the highest score was "death of spouse (score 82.7)" and the item with the lowest one was "income increase (score 24.7)." The scores of 27 out of 65 items were higher than 50. Next, 65 items were classified into 4 groups, that is, individual life, family life, occupational life, and social life. 2. Scores of the newly designed items to examine the ability to adjust oneself to place of work were "own stress tolerance (score: 73.7)" and "own stress at present (48.8)," respectively. 3. We examined the difference by sex, age, kind of occupation, position, and length of service based on the average value of stress score by t-test and the following results were obtained. 1) Scores of those in the thirties were higher than those in the twenties. 2) Section heads and leaders were under greater stress than division heads. In the same way, the differences among the four groups were analyzed and the following results were observed. 1) The only significant difference was seen in the occupational life stress group. 2) In the occupational life stress group, the scores of those in the thirties, forties, and fifties were higher than those in the twenties. Section heads and leaders were under greater stress than the staff. Workers in service for more than 21 years had higher scores than workers in service for less than 10 years. 4. The practical uses of our stress survey are also discussed in this report.

Adult↗
PubMed1999

Carbohydrate intake improves cognitive performance of stress-prone individuals under controllable laboratory stress.

Cognitive performance has been found to decline after exposure to stress, particularly in stress-prone subjects. The present study investigated whether a carbohydrate-rich, protein-poor (CR/PP) diet, which may enhance cerebral serotonin function in stress-prone subjects due to increases in the available tryptophan, improves the performance of stress-prone subjects after exposure to acute laboratory stress. Twenty-two high-stress-prone (HS) subjects and twenty-one low-stress-prone (LS) subjects aged between 19 and 26 years performed a memory scanning task after controllable and uncontrollable stress, following either a CR/PP diet or a protein-rich, carbohydrate-poor (PR/CP) isoenergetic diet. Uncontrollable stress reduced feelings of control (F(1,38) 9.30; P = 0.004), whereas pulse rate and skin conductance increased after both stress tasks (F(1,38) 78.34; P = 0.0005 and F(1,37) 83.16; P = 0.0004). Diet, stress-proneness and stress-controllability interacted (F(1,36) 9.46; P = 0.004) in such a way that performance in HS subjects was better with the CR/PP diet than with the PR/CP diet, but only after controllable stress. As the CR/PP diet has been found to increase the plasma tryptophan:large neutral amino acids ratio, indicating an increased availability of cerebral tryptophan and, thus, higher serotonin levels, it appears that there may be an increased availability of brain serotonin in HS subjects after controllable laboratory stress.

Adult↗
PubMed1998

Prenatal stress enhances stress- and corticotropin-releasing factor-induced stimulation of hippocampal acetylcholine release in adult rats.

There is growing evidence that stressors occurring during pregnancy can impair biological and behavioral responses to stress in the adult offspring. For instance, prenatal stress enhances emotional reactivity, anxiety, and depressive-like behaviors associated with a prolonged stress-induced corticosterone secretion and a reduction in hippocampal corticosteroid receptors. Among the neurotransmitters involved in these hormonal and behavioral responses, acetylcholine may play a critical role. However, it is unknown whether prenatal stressful events also may influence the development of cholinergic systems. In the present study, hippocampal acetylcholine was measured, by in vivo microdialysis, in both male and female adult prenatally stressed rats, under basal conditions, after a mild stress (saline injection) or after intracerebroventricular administration of corticotropin-releasing factor (CRF; 0.1 nM). No difference in basal release of acetylcholine was observed between control and prenatally stressed rats of both genders. Mild stress was found to increase hippocampal acetylcholine release to a greater extent in prenatally stressed rats than in controls. In males, the CRF-induced increase in hippocampal acetylcholine release was larger in prenatally stressed rats, as compared with controls, during the first hour after the injection and in females during the third hour after the injection. These data indicate that prenatal stress has long-term effects on the development of forebrain cholinergic systems. The augmented increase in hippocampal acetylcholine release after the mild stress and CRF injection in prenatally stressed rats may be involved in some of the hormonal and behavioral abnormalities found in prenatally stressed rats.

Acetylcholine↗
PubMed1988

Plasma corticosterone levels during repeated presentation of two intensities of restraint stress: chronic stress and habituation.

This study measured plasma corticosterone levels in male rats during repeated daily presentations of two intensities of restraint stress. The corticosterone response to a stress session was defined as the change from pre-stress levels to levels after 60 minutes of restraint. With the relatively intense stress imposed by four limb prone restraint, the corticosterone response partially habituated over seven days due to increasing basal corticosterone levels. However, even on day 7, there was still a large corticosterone response. With the milder stress of immobilization in a tube, the corticosterone response did not habituate at all over 21 days of repeated stress despite rising basal levels. Stress levels of corticosterone did not show significant change over days in either of the two restraint groups. Further, rising basal corticosterone levels suggest that repeated restraint produced a chronic stress state in these rats which may vary in some qualitative way with stressor intensity. Control rats placed in the same room as the stressed rats during the two stresses initially had increased corticosterone levels that matched the levels achieved in the stressed rats. The responses in control rats for the intense stress did not habituate completely in 7 days, whereas those in the control rats for the mild stress habituated completely within 3 days. These data suggest intraspecific communication of the intensity of stress.

Animals↗
PubMed2001

Modulating effects of prenatal stress on hyperthermia induced in adult rat offspring by restraint or LPS-induced stress.

The present study was carried out to investigate the effects of prenatal stress on stress-induced hyperthermia in adult rats. Prenatal stress was administered daily for 3 days (embryonic days 15-17) by restraining pregnant rats in a small cage either for 30 or 240 min. After birth, foster mothers raised the pups. Offspring were tested at 9-10-weeks-old. Changes in body temperature and in the plasma concentrations of corticosterone, norepinephrine (NE), and epinephrine (Epi) induced by restraint or lipopolysaccharide (LPS)-induced stress were examined. By comparison with the prenatally nonstressed control group, the 240-min stress group showed a significantly lower hyperthermia in response to restraint stress but a higher fever after injection of LPS. The 30-min stress group showed similar alterations in these hyperthermic responses but did not reach significance. Both the restraint stress and the injection of LPS evoked greater increases in the plasma level of corticosterone in the 240-min stress group than in the control group. Although restraint stress induced significant increases in NE and Epi in the control and 30-min stress groups, the plasma levels of these catecholamines did not increase in the 240-min stress group. These results demonstrate for the first time that prenatal stress has opposite effects on the hyperthermic responses to restraint and LPS injection, suggesting that different mechanisms underlie the modulating effects of prenatal stress on the responses to the two types of stressors.

Animals↗
PubMedDate not supplied

Stress regularity or consistency? Reading aloud Italian polysyllables with different stress patterns.

Stress assignment to three- and four-syllable Italian words is not predictable by rule, but needs lexical look-up. The present study investigated whether stress assignment to low-frequency Italian words is determined by stress regularity, or by the number of words sharing the final phonological segment and the stress pattern (stress neighborhood or consistency). Experiment 1 showed an effect of stress neighborhood: words were read aloud faster and more accurately when they had a prevalence of stress "friends," irrespective of stress regularity. Moreover, when irregularly stressed words have a higher number of stress friends compared to regularly stressed words, they are read even faster (Experiment 2). In Experiment 3, using visual lexical decision, no difference related to the numerosity of stress friends was found. It is concluded that reading aloud Italian low-frequency words with different stress patterns is mainly affected by the numerosity of lexical types that share a given final sequence and the stress pattern. The phonological nature of the numerosity of lexical representations affecting reading aloud finds support in the absence of such effect in visual lexical decision. These results have implications for models of reading aloud that go beyond monosyllables.

Decision Making↗
PubMed2006

Polyamine biosynthesis of apple callus under salt stress: importance of the arginine decarboxylase pathway in stress response.

To clarify the involvement of the arginine decarboxylase (ADC) pathway in the salt stress response, the polyamine titre, putrescine biosynthetic gene expression, and enzyme activities were investigated in apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.] in vitro callus under salt stress, during recovery after stress, and when ADC was inhibited by D-arginine, an inhibitor of ADC. Salt stress (200 mM NaCl) caused an increase in thiobarbituric acid-reactive substances (TBARS) and electrolyte leakage (EL) of the callus, which was accompanied by an increase in free putrescine content, during 7 d of treatment. Conjugated putrescine was also increased, but this increase was limited to the early stage of salt stress. Accumulation of putrescine was in accordance with induction of ADC activity and expression of the apple ADC gene (MdADC). When callus that had been treated with 200 mM NaCl was transferred to fresh medium with (successive stress) or without (recovery) NaCl, TBARS and EL were significantly reduced in the recovery treatment, indicating promotion of formation of new callus cells, compared with the successive stress treatment. Meanwhile, MdADC expression and ADC activity were also decreased in the callus undergoing recovery, whereas those of the callus under successive stress were increased. Ornithine decarboxylase (ODC) activity showed a pattern opposite to that of ADC in these conditions. D-Arginine treatment led to more serious growth impairment than no treatment under salt stress. In addition, accumulation of putrescine, induction of MdADC, and activation of ADC in D-arginine-treated callus were not comparable with those of the untreated callus. Exogenous addition of putrescine could alleviate salt stress in terms of fresh weight increase and EL. All of these findings indicated that the ADC pathway was tightly involved in the salt stress response. Accumulation of putrescine under salt stress, the possible physiological role of putrescine in alleviating stress damage, and involvement of MdADC and ADC in response to salt stress are discussed.

Arginine↗
PubMed2000

Morphological changes in osteoblastic cells (MC3T3-E1) due to fluid shear stress: cellular damage by prolonged application of fluid shear stress.

We investigated the effect of fluid shear stress on both changes in morphology and in resting level of cytosolic concentrations of Ca2+ ([Ca2+]i) in MC3T3-E1 cells, osteoblast-like cells derived from the neonatal mouse calvaria. The cells were subjected to fluid shear stress at about 1.0 Pa. Morphological characteristics were compared between stressed and control cells by scanning electron microscopic examination, actin filament evaluation using phalloidin fluorescence and [Ca2+]i measurement using fura-2/AM. The stressed cells changed from a polygonal to a spindle shape after 1-hour exposure to fluid shear stress, whereas control cells remained polygonal, and the stressed cells exhibited an increase in the number of microvilli. The diameter in the long axis of the stressed cells was significantly larger than that of controls, and about half of the stressed cells were oriented nearly along the direction of the fluid shear stress. The arrangement of the actin filaments of the stressed cells changed to parallel, and was positioned along the long axis of the cell process. The resting level of [Ca2+]i in the stressed cells showed a peak at 1 hour after the application of the stress. A more prolonged stress period over 1 hour caused cell shrinkage, an irregularity on the cell surface, and a gradual decrease in the resting level of [Ca2+]i, suggesting that prolonged stress time may cause cellular damage.

3T3 Cells↗
PubMed1998

Reactivity of blood pressure to mental arithmetic stress test, stress-test recovery time, and ambulatory blood pressure in hypertensive and normotensive subjects.

BACKGROUND: Laboratory mental stress testing and 24 h ambulatory blood pressure monitoring may analyse reactivity of blood pressure during provoked stress and stressful situations in daily-life, respectively. OBJECTIVE: To evaluate whether the responses to a mental stress test and during the stress-test recovery time were associated with ambulatory blood pressure parameters. METHODS: Fifty-two untreated male subjects (22 normotensives and 30 hypertensives) were subjected both to mental arithmetic stress testing and ambulatory blood pressure monitoring. RESULTS: We found a positive correlation between baseline and peak-test blood pressures during the stress test and 24 h blood pressures. Maximal values of systolic and diastolic blood pressures measured during the 24 h were also correlated to the maximal systolic and diastolic blood pressures reached during the stress test ( P < 0.001). We observed no relationship between reactivity during the stress test and 24 h parameters. On the contrary, changes in diastolic blood pressure during the time of recovery from the stress test (expressed as percentage-change scores) were correlated to the 24 h diastolic blood pressure parameters, the diastolic load being the most closely associated variable. CONCLUSION: The absence of relationships between variations in blood pressure during the provoked stress and ambulatory monitoring parameters indicates that reactivity of blood pressure to an acute stress does not predict the 24 h profile. However, the correlation between the maximal blood pressure measured by ambulatory monitoring and that observed during stress testing indicates that the maximal 24 h values may show the extreme blood pressure response (like the one provoked acutely by a laboratory stress test) of an individual subject. The correlation between the percentage-change score during the recovery time of diastolic blood pressure and the 24 h diastolic load could account forr a lower than normal capacity for recovery of subjects with persistently high blood pressures.

Journal Article↗
PubMed2003

Mild heat stress at a young age in Drosophila melanogaster leads to increased Hsp70 synthesis after stress exposure later in life.

In a number of animal species it has been shown that exposure to low levels of stress at a young age has a positive effect on stress resistance later in life, and on longevity. The positive effects have been attributed to the activation of defence/cleaning systems (heat shock proteins (Hsps), antioxidases, DNA repair) or to effects of a changed metabolic rate, or both. We investigated the effect of mild stress exposures early in life on Hsp70 synthesis after a harder stress exposure later in life in five isofemale lines of Drosophila melanogaster. Female flies were either exposed to repeated bouts of mild heat stress (3 h at 34 degrees C) at a young age (days 2, 4 and 6 post-eclosion) or held under standard laboratory conditions. At 16 and 32 days of adult age, respectively, flies were exposed to a high-temperature treatment known to induce Hsp70 in the investigated species (1 h at 37 degrees C). Thereafter, the inducible Hsp70 levels were measured. Our data show a tendency towards increased Hsp70 synthesis with increased age for both 'mild stress' and 'no stress' flies. Moreover, the results show that flies exposed to mild stress at a young age synthesized more Hsp70 upon induction, compared to control flies, and that this difference was accentuated at 32 days compared to 16 days of age. Thus, bouts of mild heat stress at a young age impact on the physiological stress response system later in life. This may be caused by an increased ability to react to future stresses. Alternatively, the mild stress exposure at a young age may actually have caused cellular damages increasing the need for Hsp70 levels after stress exposure later in life. The importance of an Hsp70 upregulation (throughout life) in explaining the phenomenon of hormesis is discussed, together with alternative hypotheses, and suggestions for further studies.

Animals↗
PubMed2006

Stress triggered changes in gene expression in adrenal medulla: transcriptional responses to acute and chronic stress.

1. Stress elicits activation of several transcription factors involved in the regulation of catecholamine biosynthetic enzyme gene expression depending on its duration or repetition. However, the dynamic of the conversion of transient transcriptional activation with acute stress to sustained changes in transcription in response to repeated exposure to stress in adrenomedullary catecholaminergic systems is not clear. 2. Here, we analyzed changes in levels of phospho-CREB (P-CREB), phospho-ERK1/2 (P-ERK1/2) and Fra-2 by Western Blot analysis in adrenal medulla of Sprague Dawley male rats exposed to single or repeated immobilization stress (IMO). For single stress, rats were immobilized for 5 min, 30 min, or 2 h and sacrificed immediately afterwards. In the repeated stress conditions, animals were immobilized for 2 h daily on each consecutive day prior to the final day (day 2 for 2x IMO, day 6 for 6x IMO) in which the rats were immobilized for a session lasting 5 min, 30 min or 2 h. There were two control groups, an absolute control (AC) not exposed to stress, and a handled control (HC) gently handled daily for 6 days. 3. Phosphorylation of CREB was rapid and elevated at the earliest time examined, even with single stress. However, with a second daily episode of stress the increase in P-CREB was observed for at least the entire duration of the stress. In contrast, phosphorylation of ERK1/2 was only significant after brief exposure to a single IMO. The elevation of Fra-2 protein level was slower, but was significant after 2 h of a single IMO. With repeated IMO, there were marked elevations of Fra-2 throughout the 2 h IMO, which were especially pronounced at the end of the immobilization. 4. The transient nature of the phosphorylation of CREB may be responsible for the short-lived induction of transcription of catecholamine biosynthetic enzymes after brief exposure to a single immobilization stress. The sustained phosphorylation of CREB throughout the repeated stress coupled with induction of Fra-2 may mediate the longer lasting responses to repeated stress.

Adrenal Medulla↗
PubMed1987

T-lymphocyte polyclonal proliferation: effects of stress and stress response style on medical students taking national board examinations.

This study investigated the effects of stress and stress response style on T-lymphocyte polyclonal proliferation (TLPP). The TLPP levels of 15 medical students taking NBME Part I were compared to those of a matched (on age and sex) sample of students not taking exams and hospital employees. All subjects completed the Impact of Events Scale to measure recent stress levels and style of responding to stress. TLPP data for both experimental and control groups, pre- and post-boards, were analyzed via a 2 X 2 factorial analysis of variance. Results indicated a significant main effect for the NBME stress vs control conditions and a significant interaction between stress response style (avoidance vs intrusion) and NBME stress vs control conditions. TLPP levels were significantly depressed (relative to the controls) for the NBME stress group 1 week after examinations. Furthermore, those students whose stress response style was characterized by intrusion were significantly more immunosuppressed than those characterized by an avoidance stress response style. Four- and six-week follow-up measures of TLPP were taken on 10 and 11 NBME group students, respectively. Follow-up results, analyzed via t tests, indicated that TLPP levels were significantly suppressed for 4 weeks but returned to initial normal levels at 6 weeks. Results are discussed in terms of needed research examining the mechanism of stress intruders' susceptibility to stress-induced immunosuppression and the possible clinical significance of brief periods of stress-induced decrements in TLPP levels.

Adult↗
PubMed1995

Crude saponin extracted from Vietnamese ginseng and its major constituent majonoside-R2 attenuate the psychological stress- and foot-shock stress-induced antinociception in mice.

Effects of Vietnamese ginseng (VG) crude saponin and majonoside-R2, a major saponin constituent, on the psychological stress- and foot shock stress-induced antinociception in the tail pinch test were examined in mice. VG crude saponin (6.2, 12.5, and 25 mg/kg, P.O.) attenuated psychological stress- but not foot shock stress-induced antinociceptive response, whereas majonoside-R2 (3, 6.2, and 12.5 mg/kg, P.O. and i.p.), as well as naloxone (2 mg/kg, i.p.), suppressed both psychological stress- and foot shock stress-induced antinociception. Pretreatment with the crude saponin (12.5 mg/kg, P.O.) or majonoside-R2 (6.2 mg/kg, P.O.) for 5 days followed by the treatment in combination with stress for next 5 days did not affect the development of adaptation to foot shock stress, but they significantly suppressed the antinociceptive action of the stress measured on the first, second, and third day during the stress exposure period. Majonoside-R2 (6.2 mg/kg, P.O.) but not the crude saponin (12.5 mg/kg, P.O.) significantly blocked the development of adaptation to psychological stress. These results suggest that VG crude saponin has the suppressing effect on psychological stress- and foot shock stress-induced antinociception and that majonoside-R2 is important for the action of the saponin.

Adaptation, Psychological↗
PubMed1988

Neuroendocrine correlates of sustained stress: the activity-stress paradigm.

Rats sacrificed after 4 days in the activity-stress paradigm or after 4 days of food restriction had significantly elevated levels of plasma corticosterone as compared to control rats. The approximately 5 fold increase in corticosterone in the stressed treatment groups was consistently found in all experiments. ACTH levels were elevated in activity-stress and food-restricted groups in some experiments but these increases were not statistically significant. Prolactin levels were significantly elevated in food-restricted group rats as compared to controls or activity-stress group animals in one experiment but this finding was not repeated in further experiments. In a second series of experiments, rats from activity-stressed and food-restricted treatment groups and controls were exposed to an acute stressor for 15 min prior to sacrifice to assess the effects of prior sustained stress on hormonal responses to an acute stressor. Exposure to 15 min of immobilization or intermittent footshock immediately prior to sacrifice increased plasma levels of corticosterone, ACTH and prolactin in control, food-restricted and activity-stressed rats. Generally, hormonal responses to the acute stress were similar in all treatment groups. However, in two experiments where the resting levels of corticosterone were especially elevated in the activity-stress group, the acute stress-induced rise in corticosterone was less than that seen for the other two treatment groups. In another experiment, administration of dexamethasone suppressed acute stress-evoked levels of ACTH and corticosterone in control, activity-stressed and food-restricted rats. Thus, rats exposed to 4 days of sustained stress were found to have consistently elevated resting levels of corticosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed2005

Sex and ovarian steroids modulate brain-derived neurotrophic factor (BDNF) protein levels in rat hippocampus under stressful and non-stressful conditions.

Abnormal levels of brain-derived neurotrophic factor (BDNF) are associated with major depression, a disorder with a higher incidence in women than men. Stress affects BDNF levels in various brain regions and thus, a heightened stress response in females could contribute to the development of depression. As well, ovarian hormones directly affect brain levels of BDNF mRNA and protein. Two experiments were performed to investigate the effects of stress and sex and gonadal hormones on BDNF protein levels in CA1, CA3, and dentate gyrus (DG) subregions of the hippocampus. In the first experiment, male and female Sprague-Dawley rats were subjected to one hour of restraint stress or control handling prior to sacrifice. In the second experiment, fifty-one female rats were ovariectomized and separated into stress and control conditions, as described for the first experiment. Stressed and handled groups received a single injection of estrogen (E; 53h prior to stress), estrogen and progesterone (EP; E given at 53h and P given 5h prior to stress), or vehicle (OVX). In both experiments BDNF protein was quantified using an enzyme-linked immunosorbent enzyme assay (ELISA) in micropunches of hippocampus. Gonadally intact females had significantly higher levels of BDNF in CA3, but significantly lower levels in DG, relative to males. In CA3, stress significantly decreased BDNF in both males and females. In DG of ovariectomized female rats, the effects of stress were significantly different following EP vs. vehicle treatment. Thus, stress increased BDNF levels in EP-treated rats but decreased BDNF levels in vehicle-treated rats. Reduced trophic support in DG in the presence of estrogen and progesterone could jeopardize neurogenesis and under certain conditions could be a contributing factor to the hippocampal atrophy associated with stress-induced affective disorders. These results emphasize the need to consider sex, gonadal steroids, and hippocampal subregion when examining the effects of stress on the brain.

Animals↗
PubMed1995

Shear stress-conditioned, endothelial cell-seeded vascular grafts: improved cell adherence in response to in vitro shear stress.

BACKGROUND: Prosthetic vascular grafts with adherent endothelial cell monolayers may prove useful for small-caliber vessel bypass. However, endothelial cells adhere poorly to prosthetic graft material, and they are stripped when exposed to in vivo shear stress. This study sought to determine whether in vitro shear stress conditioning improves endothelial cell adhesion and decreases thrombogenicity of endothelial cell-seeded grafts. METHODS: The lumens of 1.5 mm (inside diameter) spun polyurethane polymer vascular grafts were seeded with bovine aortic endothelial cells and cultured in vitro for 6 days with or without continuous laminar shear stress, first at 1 to 2 dynes/cm2 for 3 days, then at approximately 25 dynes/cm2 for 3 days. Grafts preconditioned by shear stress and the static control grafts were then exposed to arterial shear stress at 25 dynes/cm2 for 25 seconds. The number of dislodged cells was counted, and the grafts were examined by light and scanning electron microscopy. Whole blood clotting time in the grafts was also determined. RESULTS: Exposure of grafts to acute shear stress dislodged 1.35 x 10(6) +/- 0.44 x 10(6) cells from static grafts compared with 1.05 x 10(4) +/- 0.16 x 10(4) cells from grafts preconditioned by shear stress. By light and electron microscopy an intact endothelial monolayer was observed to cover the lumen of shear stress-conditioned grafts, whereas few cells remained on the luminal surface of grafts not previously exposed to shear stress. The clotting time in shear stress-conditioned grafts was significantly prolonged in relation to grafts not exposed to shear stress. CONCLUSIONS: These findings show that endothelial cell adhesion and retention on vascular grafts in vitro is markedly enhanced by preconditioning the seeded endothelial cell monolayer with long-term shear stress. Consequently, vascular grafts containing shear stress-conditioned endothelial monolayers are less thrombogenic in vitro than small-caliber vascular grafts without intact endothelial cell monolayers.

Animals↗
PubMed2001

Stress and symptoms in patients with interstitial cystitis: a life stress model.

Objectives. Stress-related exacerbation of interstitial cystitis (IC) symptoms has frequently been reported. Previous research has found stress-related IC symptom exacerbation in an experimental model. However, this relationship has not been objectively examined with daily life stressors. We used a prospective daily symptom diary method to investigate the relationships among stress and bladder symptoms in patients with IC and age-matched healthy controls.Methods. Forty-five previously diagnosed female patients with IC completed a bladder symptom and stress diary nightly for 1 month; 31 female age-matched healthy controls completed a similar diary for 7 days. The symptom questions were modified from the Interstitial Cystitis Data Base study.Results. Patients reported greater mean daily stress, bladder pain, urgency, and daytime and nocturnal frequency than controls (all P values less than 0.001). Among all patients, a significant relationship between stress and urgency was observed. In addition, a significant relationship between stress and pain was observed among patients with moderate and severe disease. As the disease severity increased, more pronounced relationships between stress and the symptoms of urgency and pain were evidenced. Greater stress was associated with greater nocturnal frequency among patients with more severe disease. These stress-symptom relationships were not observed among the controls.Conclusions. Higher levels of stress were related to greater pain and urgency in patients with IC but not in the controls. In addition, the relationship of stress and these IC symptoms was stronger among patients with more severe disease. The results indicate that life stress is associated with greater IC symptoms, particularly among patients whose disease is not well controlled.

Activities of Daily Living↗