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1.
The combination of living at altitude and training near sea level [live high-train low (LHTL)] may improve performance of endurance athletes. However, to date, no study can rule out a potential placebo effect as at least part of the explanation, especially for performance measures. With the use of a placebo-controlled, double-blinded design, we tested the hypothesis that LHTL-related improvements in endurance performance are mediated through physiological mechanisms and not through a placebo effect. Sixteen endurance cyclists trained for 8 wk at low altitude (<1,200 m). After a 2-wk lead-in period, athletes spent 16 h/day for the following 4 wk in rooms flushed with either normal air (placebo group, n = 6) or normobaric hypoxia, corresponding to an altitude of 3,000 m (LHTL group, n = 10). Physiological investigations were performed twice during the lead-in period, after 3 and 4 wk during the LHTL intervention, and again, 1 and 2 wk after the LHTL intervention. Questionnaires revealed that subjects were unaware of group classification. Weekly training effort was similar between groups. Hb mass, maximal oxygen uptake (VO(2)) in normoxia, and at a simulated altitude of 2,500 m and mean power output in a simulated, 26.15-km time trial remained unchanged in both groups throughout the study. Exercise economy (i.e., VO(2) measured at 200 W) did not change during the LHTL intervention and was never significantly different between groups. In conclusion, 4 wk of LHTL, using 16 h/day of normobaric hypoxia, did not improve endurance performance or any of the measured, associated physiological variables.  相似文献   

2.
ABSTRACT: BACKGROUND: The incidence of postoperative nausea and vomiting is 50% to 80% after neurosurgery. The common prophylactic treatment for postoperative nausea and vomiting is a triple therapy of droperidol (Inapsine), promethazine (Phenergan) and dexamethasone (Decadron). Newer, more effectives methods of prophylaxis are being investigated. We designed this prospective, double-blind, single center study to compare the efficacy of ondansetron (Zofran) to a neurokinin-1 antagonist, aprepitant (Emend), as a substitute for droperidol, in the prophylactic treatment of postoperative nausea and vomiting after neurosurgery. METHODS: After obtaining institutional review board approval, One hundred-seventy-six patients, 18-85 years of age with ASA I to III, who did not receive anti-emetics 24 hours before surgery and are expected to undergo general anesthesia for neurosurgery lasting longer than two hours were included in this study. After meeting the inclusion and exclusion criteria and providing written informed consent, patients will be randomly assigned in a 1:1 ratio to one of two treatment groups: aprepitant or ondansetron. Because ondansetron is given intravenously and aprepitant orally, patients will be given an oral or intravenous placebo to maintain the double blind. Patients will receive aprepitant 40 mg PO/placebo within 2 hours prior to induction. At induction, a combination of intravenous dexamethasone 10 mg, promethazine 25 mg and ondansetron 4 mg/placebo will be given. The primary outcome measures are the episodes and severity of nausea and vomiting; administration of rescue antiemetic; and opioid consumption for 120 hours postoperatively. Standard safety assessments will include adverse event reports, physical and laboratory data, awakening time and duration of recovery from anesthesia. Logistic regression will be used to test the efficacy of aprepitant compared to ondansetron with demographic characteristics as potential covariates in the model. For the number of rescue therapy treatments used during the postoperative period, a Wilcoxon rank sum test will be performed. DISCUSSION: The results of this comparative study will potentially identify an improved treatment regimen that will decrease the incidence and severity of postoperative nausea and vomiting in patients undergoing neurosurgery. This will serve to enhance patient recovery and overall satisfaction of neurosurgical patients in the immediate postoperative period. Registered at The Ohio State University Biomedical Sciences Institutional Review Board: Protocol Number: 2007H0053 KEYWORDS: aprepitant, postoperative nausea and vomiting, craniotomy, ondansetron. Word Count: 347.  相似文献   

3.
One hundred and seventy four patients suffering from the restless legs syndrome were examined in a double blind, between patient, placebo controlled study in general practice for five weeks to investigate the effects of carbamazepine and placebo on the syndrome. The syndrome was more common among middle aged women with relatively low systolic blood pressure. The median haemoglobin concentration was about average for the population, but the severity of the symptoms seemed to increase with decreasing concentrations of haemoglobin. Both placebo and carbamazepine showed a significant therapeutic effect (p less than 0.01). Carbamazepine was significantly more effective than placebo (p less than or equal to 0.03). The significant therapeutic effect of placebo in restless legs showed that only double blind controlled trials can confirm the efficacy of suggested treatments.  相似文献   

4.
One-third of the Dutch population suffers from allergic rhinitis, including hay fever. In this study, a 5-day-ahead hay fever forecast was developed and validated for grass pollen allergic patients in the Netherlands. Using multiple regression analysis, a two-step pollen and hay fever symptom prediction model was developed using actual and forecasted weather parameters, grass pollen data and patient symptom diaries. Therefore, 80 patients with a grass pollen allergy rated the severity of their hay fever symptoms during the grass pollen season in 2007 and 2008. First, a grass pollen forecast model was developed using the following predictors: (1) daily means of grass pollen counts of the previous 10 years; (2) grass pollen counts of the previous 2-week period of the current year; and (3) maximum, minimum and mean temperature (R 2?=?0.76). The second modeling step concerned the forecasting of hay fever symptom severity and included the following predictors: (1) forecasted grass pollen counts; (2) day number of the year; (3) moving average of the grass pollen counts of the previous 2 week-periods; and (4) maximum and mean temperatures (R 2?=?0.81). Since the daily hay fever forecast is reported in three categories (low-, medium- and high symptom risk), we assessed the agreement between the observed and the 1- to 5-day-ahead predicted risk categories by kappa, which ranged from 65 % to 77 %. These results indicate that a model based on forecasted temperature and grass pollen counts performs well in predicting symptoms of hay fever up to 5 days ahead.  相似文献   

5.
One of the most important events in the natural history of BPH is acute urinary retention (AUR). Better estimates of AUR incidence are now available from both population-based studies and placebo control groups (patients diagnosed with BPH). Several strong risk factors for AUR have been identified by analytical epidemiology, the most important being serum PSA levels. When counseling patients with BPH who are considering watchful waiting, clinicians should also take into account prostate volume, maximum flow rate, and symptom severity.  相似文献   

6.
Eighteen patients with stable mild hypertension (mean blood pressure 144/93 mm Hg) restricted their sodium intake for eight weeks while taking part in a double blind randomised crossover trial of slow sodium and placebo tablets. Mean 24 hour urinary sodium excretion was 143 mmol(mEq) during the period on slow sodium and 87 mmol during the period on placebo. Five patients were unable to reduce their sodium intake below 120 mmol, but the others had a mean 24 hour urinary sodium excretion of 59 mmol during the period on placebo. There was no significant difference in blood pressure between the slow sodium and placebo treatment periods, although the study had a power of 99% to detect a difference of 5 mm Hg in mean arterial pressure between the two periods. Moderate dietary sodium restriction does not lower blood pressure in patients with this degree of hypertension.  相似文献   

7.
P. C?té  R. Lamontagne  L. Campeau  M.G. Bourassa 《CMAJ》1977,117(11):1281-1284
In 134 patients with coronary artery disease, long-term oral anticoagulant therapy (mean duration, 56 months) for acute myocardial infarction (98 patients), acute coronary insufficiency (25 patients) or severe chronic angina (11 patients) was terminated abruptly in 50 patients (group 1) and gradually in 84 (group 2). The 134 patients represented a homogeneous population of patients with coronary artery disease since most patients older than 75 years and those with conditions known to increase the risks of thromboembolic complications were excluded. The two groups were comparable in terms of sex, age, presence of risk factors, duration of anticoagulant therapy, and presence of angina and abnormal resting electrocardiograms during therapy. Patients were evaluated 6 months after cessation of anticoagulant therapy and, since abrupt withdrawal of therapy did not carry a higher risk than gradual discontinuation, data for groups 1 and 2 were tabulated together.Of the 84 patients with angina at the end of therapy 15 experienced an increase in its severity and this symptom appeared in another patient (relapse rate, 18%). Angina progressed to fatal acute myocardial infarction in four (mortality, 3%) and nonfatal infarction in two; however, all six had extensive coronary artery disease and poor left ventricular function. The results of this study suggest that neither abrupt nor gradual cessation of anticoagulant therapy is associated with an inordinate exacerbation of heart disease.  相似文献   

8.
Eighteen climbers actively ascended Mount Rainier (elevation 4,392 m) twice during a randomized, double-blind, concurrent, placebo-controlled, crossover trial comparing the use of acetazolamide, 250 mg, dexamethasone, 4 mg, and placebo every 8 hours as prophylaxis for acute mountain sickness. Each subject was randomly assigned to receive placebo during one ascent and one of the active medications during the other ascent. Assessment of acute mountain sickness was performed using the Environmental Symptoms Questionnaire and a clinical interview. At the summit or high point attained above base camp, the use of dexamethasone significantly reduced the incidence of acute mountain sickness and the severity of symptoms. Cerebral and respiratory symptom severity scores for subjects receiving dexamethasone (0.26 +/- 0.16 and 0.20 +/- 0.19, respectively) were significantly lower than similar scores for both acetazolamide (0.80 +/- 0.80 and 1.20 +/- 1.05; P = 0.25) and placebo (1.11 +/- 1.02 and 1.45 +/- 1.27; P = .025). Neither the use of dexamethasone nor that of acetazolamide measurably affected other physical or mental aspects. Compared with placebo, dexamethasone appears to be effective for prophylaxis of symptoms associated with acute mountain sickness accompanying rapid ascent. The precise role of dexamethasone for the prophylaxis of acute mountain sickness is not known, but it can be considered for persons without contraindications who are intolerant of acetazolamide, for whom acetazolamide is ineffective, or who must make forced, rapid ascent to high altitude for a short period of time with a guaranteed retreat route.  相似文献   

9.
Twenty-four hour patterns of body temperature (BT) were recorded during consecutive 3-10 day spans from 14 severely brain-damaged patients. Seven patients exhibited a normal circadian BT rhythm with an amplitude of more than 1°C and a normal phase position of the minimum BT being observed during the latter half of the nocturnal sleep. One patient with a dispersed type of sleep exhibited an extremely low amplitude of the BT rhythm with mean average 0.69°C. In this patient, an 24-hr observation span was insufficient to detect the existence of a BT rhythm. Two patients manifested disturbance of period. As acrophase of the BT rhythm varied from day to day, the standard deviation (S.D.) of mean acrophase wasextremely large. For these patients the light-dark cycle did not act as an entrainer because both had visual disturbance. A phase advance of the minimum BT was observed in four patients. The minimum BT appeared in the first half of nocturnal sleep. These three disturbances (amplitude, period and phase), were revealed only by longitudinal observation of the BT rhythm, indicating the importance of long-term observations over a sufficient period to make the nature of the rhythm disturbances clear. These disturbances were not related to that of the sleep-wake cycle, as two patients showed normal circadian BT rhythm in spite of their dispersed-type sleep.  相似文献   

10.

Background

It is unclear whether the benefits that some patients derive from complementary and integrative medicine (CIM) are related to the therapies recommended or to the consultation process as some CIM provider visits are more involved than conventional medical visits. Many patients with gastrointestinal conditions seek out CIM therapies, and prior work has demonstrated that the quality of the patient-provider interaction can improve health outcomes in irritable bowel syndrome, however, the impact of this interaction on gastroesophageal reflux disease (GERD) is unknown. We aimed to assess the safety and feasibility of conducting a 2x2 factorial design study preliminarily exploring the impact of the patient-provider interaction, and the effect of an over-the-counter homeopathic product, Acidil, on symptoms and health-related quality of life in subjects with GERD.

Methods

24 subjects with GERD-related symptoms were randomized in a 2x2 factorial design to receive 1) either a standard visit based on an empathic conventional primary care evaluation or an expanded visit with questions modeled after a CIM consultation and 2) either Acidil or placebo for two weeks. Subjects completed a daily GERD symptom diary and additional measures of symptom severity and health-related quality of life.

Results

There was no significant difference in GERD symptom severity between the Acidil and placebo groups from baseline to follow-up (p = 0.41), however, subjects who received the expanded visit were significantly more likely to report a 50% or greater improvement in symptom severity compared to subjects who received the standard visit (p = 0.01). Total consultation length, perceived empathy, and baseline beliefs in CIM were not associated with treatment outcomes.

Conclusion

An expanded patient-provider visit resulted in greater GERD symptom improvement than a standard empathic medical visit. CIM consultations may have enhanced placebo effects, and further studies to assess the active components of this visit-based intervention are warranted.

Trial Registration

ClinicalTrials.gov NCT01915173  相似文献   

11.
Studies show evidence of longitudinal brain volume decreases in schizophrenia. We studied brain volume changes and their relation to symptom severity, level of function, cognition, and antipsychotic medication in participants with schizophrenia and control participants from a general population based birth cohort sample in a relatively long follow-up period of almost a decade. All members of the Northern Finland Birth Cohort 1966 with any psychotic disorder and a random sample not having psychosis were invited for a MRI brain scan, and clinical and cognitive assessment during 1999–2001 at the age of 33–35 years. A follow-up was conducted 9 years later during 2008–2010. Brain scans at both time points were obtained from 33 participants with schizophrenia and 71 control participants. Regression models were used to examine whether brain volume changes predicted clinical and cognitive changes over time, and whether antipsychotic medication predicted brain volume changes. The mean annual whole brain volume reduction was 0.69% in schizophrenia, and 0.49% in controls (p = 0.003, adjusted for gender, educational level, alcohol use and weight gain). The brain volume reduction in schizophrenia patients was found especially in the temporal lobe and periventricular area. Symptom severity, functioning level, and decline in cognition were not associated with brain volume reduction in schizophrenia. The amount of antipsychotic medication (dose years of equivalent to 100 mg daily chlorpromazine) over the follow-up period predicted brain volume loss (p = 0.003 adjusted for symptom level, alcohol use and weight gain). In this population based sample, brain volume reduction continues in schizophrenia patients after the onset of illness, and antipsychotic medications may contribute to these reductions.  相似文献   

12.
Twenty-five patients with perennial rhinitis completed a double-blind cross-over trial of intranasal beclomethasone dipropionate 200 μg daily and placebo. Of these patients 19 preferred the active drug and two preferred placebo. There were significant reductions in symptom scores for nasal obstruction and rhinorrhoea and in the use of decongestant nasal drops when using the active drug. No changes in morning plasma cortisol levels occurred during the three-week treatment period.  相似文献   

13.
Metformin often promotes weight loss in patients with obesity with non-insulin-dependent diabetes mellitus (NIDDM). The mechanism may be attributed to decreased food intake. This study has tested the effect of metformin on satiety and its efficacy in inducing weight loss. Twelve diet-treated NIDDM women with obesity were randomly given two dose levels (850 mg or 1700 mg) of metformin or placebo at 0800 for three consecutive days followed by a meal test on the third day on three occasions using a 3times3 Latin square design. The number of sandwich canapes eaten in three consecutive 10-minute periods beginning at 1400 hours was used to quantitate food intake, and the level of subjective hunger was rated just before the sandwich meal with a linear analogue hunger rating scale at 1400 after a 6-hour fast. The prior administration of metformin produced a reduction in calorie intake after each of the two doses of metformin treatment. The 1700-mg metformin dose had the most marked appetite suppressant action. Similarly, hunger ratings were significantly lowered after metformin, and the effect was most pronounced after the administration of 1700 mg of metformin. To assess the efficacy of metformin in reducing bodyweight, 48 diet-treated NIDDM women with obesity who had failed to lose weight by diet therapy were first placed on a 1200-kcal ADA (American Diabetes Association) diet before being randomized to receive either metformin (850 mg) or placebo twice daily in a double-blind fashion for 24 weeks. A 4-week single-blind placebo lead-in period preceded and a 6-week single-blind placebo period followed the 24-week double-blind treatment period. Subjects treated with metformin continued to lose weight throughout 24 weeks of treatment; their mean maximum weight loss was 8 kg greater than that of the placebo group, with corresponding lower HbA1C and fasting blood glucose levels at the end of the active treatment period. These results indicate that metformin decreases calorie intake in a dose-dependent manner and leads to a reduction in bodyweight in NIDDM patients with obesity.  相似文献   

14.
Shlomo Cohen 《Bioethics》2014,28(3):147-154
The nocebo effect, the mirror‐phenomenon to the placebo effect, is when the expectation of a negative outcome precipitates the corresponding symptom or leads to its exacerbation. One of the basic ethical duties in health care is to obtain informed consent from patients before treatment; however, the disclosure of information regarding potential complications or side effects that this involves may precipitate a nocebo effect. While dilemmas between the principles of respect for patient autonomy and of nonmaleficence are recognized in medical ethics, there has not yet been an ethical discussion focused on the potential dilemma raised by the nocebo effect of informed consent (NEIC). This dilemma is especially pernicious, since it involves a direct causality of harm by the caregiver that is unparalleled by other potential harmful effects of information disclosure. This paper articulates the dilemma of the NEIC and offers a seminal ethical analysis.  相似文献   

15.
Pectinidae spat collecting was carried out during a period of 1.5 years in the southern lagoon of New Caledonia. The majority of spat collected were constituted by Mimachlamys gloriosa and Brachtechlamys vexillum larvae. Settlement showed quantitative variations during the year with a maximum in June-September and a minimum (close to zero) in summer (February). However, although adult stocks maintain a stable density and spawn all the year round, spawning intensity shows a maximum in austral summer, contrarily to the recruitment. Therefore, spawning and spat collecting present no correlation and high values of the gonadic index are not followed by numerous spat collecting. These two tropical species present an opportunistic reproductive model.  相似文献   

16.
Kover PX  Wolf JB  Kunkel BN  Cheverud JM 《Heredity》2005,94(5):507-517
Plant pathogens can severely reduce host yield and fitness. Thus, investigating the genetic basis of plant response to pathogens is important to further understand plant-pathogen coevolution and to improve crop production. The interaction between Arabidopsis thaliana and Pseudomonas syringae is an important model for studying the genetic basis of plant-pathogen interactions. Studies in this model have led to the discovery of many genes that differentiate a resistant from a susceptible plant. However, little is known about the genetic basis of quantitative variation in response to P. syringae. In this study, we investigate the genetic basis of three aspects of A. thaliana's response to P. syringae: symptom severity, bacterial population size and fruit production using a quantitative trait loci (QTL) analysis. We found two QTL for symptom severity and two for fruit production (possible candidate genes for observed QTL are discussed). We also found significant two-locus epistatic effect on symptom severity and fruit production. Although bacterial population size and symptom severity were strongly phenotypically correlated, we did not detect any QTL for bacterial population size. Despite the detected genetic variation observed for susceptibility, we found only a weak overall relationship between susceptibility traits and fitness, suggesting that these traits may not respond to selection.  相似文献   

17.
A capture-recapture design was applied between January 1989 and June 1991 in a 37 5 ha area located in the central valley of the Tiber River (Latium), aimed at estimating the demographic parameters of a coypu population in the Mediterranean climate and at preliminarily investigating the factors that regulate its numbers in this region The population fluctuated between 27 and 137 individuals and followed a seasonal pattern It decreased after the winter and increased between summer and winter Density remained almost stable during a particularly mild winter Survival rates remained relatively high over the entire study period, reproductive activity and additions to the population from in situ reproduction, however, showed minimum peaks following colder winters Evidence of immigration was detected during periods of increasing density Key factor and preliminary density dependence analyses showed that pregnancy failure and newborn losses are cumulatively the most important factor contributing to varation in total mortality, and are positively related to coypu numbers in previous periods The failure to realize maximum potential fecundity is inversely related to previous coypu abundance We show that post-recruitment losses play only a minor role in determining population decline  相似文献   

18.
Although it is thought that transverse rectus abdominis muscle (TRAM) flap breast reconstruction produces excellent cosmetic results that are maintained over the long term, there is little objective evidence in the literature to support this. One hundred seventy-one consecutive patients who underwent TRAM flap reconstruction were prospectively analyzed over an 8-year period to assess their morbidity and late cosmetic outcome.The early patient complication rate (< 2 months) was 37.4 percent, the late hernia and fat necrosis rates (> 2 months) were 8.8 and 13.5 percent, respectively, and the contralateral symmetrization rate was 33.9 percent. The cosmetic results were evaluated prospectively using an objective five-point global scale. Each patient was scored at each visit once surgery was completed. Follow-up continued until a flap was lost, a patient died, or the point of last patient contact was reached. Six patients died during the study. The actuarial percentage cosmetic outcome remained stable during the study period, with an acceptable result in 96.4 percent of patients at 2 years and in 94.2 percent of patients at 5 years. Only five patients in this series obtained poor cosmetic outcomes, with three due to substantial flap necrosis and two because of poor flap design. Two free TRAM flaps were also lost. Log-rank analysis revealed that neither patient age nor timing of surgery significantly affected the cosmetic outcome. Single pedicle and supercharged (single pedicle) TRAM flaps produced slightly better results than bipedicle and free TRAM flaps. In this prospective longitudinal study, TRAM flap reconstructions were shown to produce aesthetically pleasing results. Moreover, with long-term follow-up, it was demonstrated that these reconstructions maintained their stability.  相似文献   

19.
The role of Helicobacter pylori infection in nonulcer dyspepsia remains controversial. To date studies exploring the effect of H. pylori eradication on symptoms have reported conflicting results. Randomised control trials employing validated outcome measures have also been difficult to interpret because of several important issues such as the large placebo response seen in patients with nonulcer dyspepsia and both the natural variability in symptoms and symptom severity with time. The association of symptom improvement with resolution of gastritis has meant that the length of follow up employed in most studies has been insufficient. We report the findings of a randomised placebo controlled trial (n = 100), using a validated symptom questionnaire and 5 year follow up to determine the effect of H. pylori eradication on symptoms in nonulcer dyspepsia. In all 64 that were reviewed at 5 years there was a significant difference between patients who were H. pylori negative and those who remained positive with regard to complete symptom resolution, consumption of relevant medications and peptic ulcer disease development, in favour of active treatment. There was a trend for gradual symptom improvement over time irrespective of H. pylori status, which may reflect the natural history of this condition. For those who remained symptomatic at 5 years, there was no difference in symptom severity based on H. pylori status. The findings of this study support the use of H. pylori eradication in symptomatic patients with nonulcer dyspepsia both to induce symptom resolution and to prevent disease progression.  相似文献   

20.
A significantly high number of patients with anorexia nervosa are overweight immediately before the onset of the condition. This premorbid weight may be a feature of their constitution but is sometimes a more transitory phenomenon. Menstruation ceases early in the condition but usually within the context of significant weight loss. However, the subsequent amenorrhoea, related to factors that presumably may not begin to operate until several weeks later, may be a symptom which first draws attention to the condition.Treatment included the restitution of body weight to the matched population mean weight for each patient. This may be important, as the mean weight at which menstrual activity returned was not significantly different from the matched population mean weight. A further treatment aim, so far as nutrition was concerned. was restoration of regular and reasonable feeding behaviour, including adequate carbohydrate ingestion. It is suggested that these findings support the view that the nutritional disturbance in anorexia nervosa is an important factor affecting menstrual activity.  相似文献   

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