Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FLASH”

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 217 records · Page 12Linked to original sources
PubMed1985

Visual evoked potential correlates of laser flashblindness in rhesus monkeys. II. Doubled-neodymium laser flashes.

The effects of Q-switched (20-ns) doubled-neodymium (Nd-2) laser flashes upon the visual evoked potential (VEP) of two rhesus monkeys were studied and compared with the effects of 100-ms argon laser flashes described previously. VEP's were recorded under barbiturate anesthesia using bipolar electrodes chronically implanted in foveal striate cortex, and were elicited by 6-Hz phase-reversing gratings. The parameters which were investigated included the retinal area and energy level of the flash, and the wavelength, spatial frequency, and contrast of the test grating. The effects produced by the Q-switched pulses at 50% of the maximum permissible exposure (MPE) were smaller in magnitude than those produced by the longer duration argon flashes. The reduced effects of the Nd-2 pulses were attributed to the lower energy contained in these flashes, as dictated by the MPE standards. In other respects, the Nd-2 flash effects closely paralleled the argon effects. The results of the various experiments suggest that VEP decrements produced by long and short flashes are similar at equal energy levels, despite the fact that the shorter flashes are believed to produce considerably less pigment bleaching.

Animals↗
PubMed1995

Calcium current reactivation after flash photolysis of nifedipine in skeletal muscle fibres of the frog.

1. L-type calcium currents were activated by depolarization of cut muscle fibres of the frog. The current was blocked by the dihydropyridine compound nifedipine (5-10 microM) and reactivated by flash photolysis of the drug. 2. In the presence of nifedipine, increasing the time interval between the onset of depolarization and the flash resulted in progressively faster kinetics of the flash-induced current. This change developed with a slow time course similar to that of normal current activation. 3. A fast gating mode of the normally slow L-type channel was induced by conditioning activation (500 ms prepulses) applied 80 ms before a test step to the same potential. After block by nifedipine, flash-photolysis was carried out 40 ms before the end of the long conditioning pulse. The flash-induced current had the same rapid time course as the current activated by the subsequent test voltage step. 4. Similarly, the time course of current activation was comparable for the voltage-induced fast mode activation (flash applied 5 ms before the test step) and the flash-induced activation 40 ms after the onset of the test depolarization. 5. Our data suggest that in frog skeletal muscle nifedipine inhibits calcium current activation by blocking a rapid channel gating step while the slow conformational change that normally limits the rate of activation of the L-type calcium channel remains unaffected. UV flash illumination results in a fast reactivation indicating that the channels need not be inactivated to be blocked by nifedipine.

Animals↗
PubMed1995

Light adaptation and the rising phase of the flash photocurrent of salamander retinal rods.

1. Both theory and analysis of photocurrents in retinal rods show that phosphodiesterase activity after a flash rises initially as a delayed ramp. 2. The effect of light adaptation on the flash-induced rise in phosphodiesterase activity deduced from photocurrent responses was investigated. 3. Background adaptation reduces the deduced rate of rise of phosphodiesterase activity. The effect is most prominent for bright backgrounds and moderate flashes. There is little reduction for bright flashes, even in bright backgrounds. There is no effect for weak backgrounds. 4. Light adaptation after bleaching visual pigment produces a reduction in the deduced rise of phosphodiesterase activity for all flashes. For bright flashes, the reduction is explained by the reduction in quantum catch. For moderate flashes, there is an extra reduction, similar to the reduction produced by the equivalent background. 5. The results provide support for the idea that a reduction in the amplification step of phototransduction functions as part of the mechanism of light adaptation in rods. The dependence on flash intensity of the background-induced reduction in phosphodiesterase activation could imply a feedback mechanism on the activation steps of phototransduction.

Adaptation, Ocular↗
PubMed1975

Body temperatures during menopausal hot flashes.

Body temperatures during hot flashes were measured in a menopausal woman. Internal temperatures fell after each flash; lowest: rectal, 35.6 degrees C; vaginal, 35.6 degrees C; tympanic, 35.2 degrees C. Where sweating occurred, the skin temperature fell during the flash and rose after it. Finger and toe temperatures always showed a sharp rise at the onset of a flash with a slower fall after the flash. Only the cheeks showed additional temperature rises; maximum, 0.7 degrees C. The heart accelerated 13% at the onset of the flash but slowed immediately thereafter. The flash interval was sharply demarcated by undulations in the ECG baseline. There was never any premonitory sign of the imminence of a flash. A central excitatory state seemed to build up, perhaps by the accumulation of a chemical compound, but not of heat, which was explosively dischargedmthe thermal distress was probably evoked by vascular warming in the cheeks. Dabbing the malar prominences with cold water brought prompt relief.

Body Temperature↗
PubMed2001

The flash-lag effect as a spatiotemporal correlation structure.

The flash-lag effect refers to the phenomenon in which a flash adjacent to a continuously moving object is perceived to lag behind it. Phenomenally, the flash appears to be spatially shifted relative to the moving stimulus, and the amount of lag has often been quantified as the flash's nulling position, which is the physical spatial offset needed to establish perceptual alignment. The present study offers a better way to summarize flash-lag data. Instead of plotting data in terms of space, the psychometric function of the observer's relative-position judgment is drawn on spatiotemporal plot. The psychological process underlying illusory lag is formulated as spatiotemporal bias and uncertainty and their estimate as a spatiotemporal convolution kernel that best explains the spatiotemporal psychometric function. Two empirical procedures of kernel estimation are described. One procedure is to fit the free parameters of the kernel to experimental data for continuous motion trajectory. The second is to give an analytical solution to the kernel using experimental data for random motion trajectory. The two procedures yield similar kernels, with negligible spatial bias and uncertainty and substantial temporal bias and uncertainty. In addition, it is demonstrated that an experimental manipulation of temporal predictability of the flash can change the temporal bias in the estimated kernel. The results of this novel analysis reveal that the flash-lag effect is viewed as a spatiotemporal correlation structure, which is largely characterized by the tendency to compare the position of the flash in the past with the position of the moving item in the present.

Humans↗
PubMed1985

Changes in neurotensin-like immunoreactivity during menopausal hot flashes.

An elevation of plasma immunoreactive neurotensin (iNT) was found during menopausal hot flashes. The flash-associated increases in iNT were concomitant with several physiological changes, including increased heart rate, finger blood flow, and finger temperature. Plasma iNT during hot flashes increased 245 +/- 65% (+/- SEM; n = 41), peaking 3.6 +/- 0.4 min after the onset of the hot flash. Immunochemical and chromatographic analyses indicated that the components of iNT elevated during a hot flash consisted primarily of C-terminal-related variants of NT, but not NT itself or any of its known metabolites. The three major substances identified using high pressure liquid chromatography and a C-terminal-directed RIA that appeared in women with hot flashes were also present in plasma of women without hot flashes and men. Since NT is a vasoactive and cardioactive peptide that can also affect temperature regulation, our results suggest the active involvement of these variants of NT in hot flashes.

Adult↗
PubMed2000

Sunset science. III. Visual adaptation and green flashes.

Photographs of green flashes do not preclude a role for physiological effects in these phenomena. While green flashes are certainly not after-images, there is compelling evidence that adaptation in the visual system strongly affects the perceived color of most sunset green flashes. Furthermore, the retinal image of the setting Sun is usually bright enough to bleach most of the red-sensitive photopigment in a few seconds, making the yellow stage of a sunset flash appear green. Even in air so hazy that no green light reaches the eye, a yellow flash may occur and appear green. Many, but not all, visual observations of sunset green flashes are of this yellow flash. The yellow portion of sunset green flashes helps explain their reported durations, which exceed those expected for the appearance of green light alone.

Adaptation, Physiological↗
PubMed1978

Detection of red and green flashes: evidence for cancellation and facilitation.

Green and red flashes of light will differentially stimulate the middle- and long-wavelength sensitive cones. Interaction of cone signals was studied by measuring increment thresholds for combinations of green and red flashes on a yellow adapting field. When the yellow adapting field was at 10.000 trolands (td), green and red incremental flashes (1 degree, 200-msec duration) produced cancellation when presented simultaneously and facilitation when presented sequentially. A green incremental flash (1.15 degrees, 200 msec, 5000-td adaptation field) and red decremental flash, or vice versa, produced facilitation when presented simultaneously. The results can be explained by color-differencing, opponent-mechanisms. The cancellation effect for the simultaneous incremental flashes largely disappeared when the flashes were exposed briefly (10 msec) or reduced in size (0.04 degrees). It is unlikely that the stimuli were exclusively detected by achromatic, luminance channels, as suggested by previous work, since observers could partially distinguish the hue of threshold flashes of 570- and 590-nm light (0.04 degrees, 10 msec) on a bright yellow field.

Color Perception↗
PubMed1993

Hyperparathyroidism--comparison of flash imaging with spin echo MR imaging.

MR images of the neck were prospectively studied in 19 patients with hyperparathyroidism. Fast low angle shot (FLASH) sequence was performed in addition to T1- and T2-weighted spin echo (SE) sequences. FLASH images were obtained with 320/12/20 degrees (TR/TE/flip angle) using presaturation technique. TE of 12 ms was chosen to eliminate high signal of fat tissue. In the evaluation of detectability, a combination of T1-weighted SE and FLASH images (T1WI + FLASH) was compared with a combination of T1- and T2-weighted SE images (T1WI + T2WI). MR imaging correctly depicted 20 of 30 abnormal glands on both T1WI + FLASH and T1WI + T2WI. FLASH imaging effectively eliminated high signal of fat tissue. Nineteen abnormal glands demonstrated higher signal than surrounding tissues on FLASH images, whereas 12 glands were high-intense on T2-weighted SE images. We conclude that FLASH imaging provides improved tissue contrast and anatomic delineation and, thus, may replace T2-weighted SE imaging in the neck.

Adenoma↗
PubMed2003

Paroxetine controlled release in the treatment of menopausal hot flashes: a randomized controlled trial.

CONTEXT: Standard therapy for hot flashes has been hormone replacement with estradiol or progestational agents, but recent data suggest that antidepressants inhibiting serotonin reuptake may also be effective. OBJECTIVE: To evaluate a selective serotonin reuptake inhibitor (paroxetine controlled release [CR]) in treating the vasomotor symptoms displayed by a general cross-section of menopausal women. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled, parallel group study conducted across 17 US sites, including urban, suburban, and rural clinics. PATIENTS: A total of 165 menopausal women aged 18 years or older experiencing at least 2 to 3 daily hot flashes and must have discontinued any hormone replacement therapy for at least 6 weeks. Women were excluded if they had any signs of active cancer or were undergoing chemotherapy or radiation therapy. INTERVENTION: After a 1-week placebo run-in phase, study participants were randomized to receive placebo or receive 12.5 mg/d or 25.0 mg/d of paroxetine CR (in a 1:1:1 ratio) for 6 weeks. MAIN OUTCOME MEASURES: Mean change from baseline to week 6 in the daily hot flash composite score (frequency x severity). RESULTS: Fifty-six participants were randomly assigned to receive placebo and 51 to receive 12.5 mg/d and 58 to receive 25.0 mg/d of paroxetine CR. The mean reductions in the hot flash frequency composite score from baseline to week 6 were statistically significantly greater for those receiving paroxetine CR than for those receiving placebo. By week 6, the mean daily hot flash frequency went from 7.1 to 3.8 (mean reduction, 3.3) for those in the 12.5-mg/d and from 6.4 to 3.2 (mean reduction, 3.2) for those in the 25-mg/d paroxetine CR groups and from 6.6 to 4.8 (mean reduction, 1.8) for those in the placebo group. Mean placebo-adjusted reduction in hot flash composite scores were -4.7 (95% confidence interval, - 8.1 to -1.3; P =.007) comparing 12.5-mg/d paroxetine CR with placebo; and -3.6 (95% confidence interval, -6.8 to -0.4; P =.03) comparing 25.0-mg/d paroxetine CR with placebo. This corresponded to median reductions of 62.2% for those in the 12.5-mg/d and 64.6% for those in the 25.0-mg/d paroxetine CR groups compared with 37.8% for those in the placebo group. CONCLUSION: Paroxetine CR may be an effective and acceptable alternative to hormone replacement and other therapies in treating menopausal hot flash symptoms.

Adult↗
PubMed2003

Phytoestrogen supplements for the treatment of hot flashes: the Isoflavone Clover Extract (ICE) Study: a randomized controlled trial.

CONTEXT: Clinical trials demonstrating increased risk of cardiovascular disease and breast cancer among women randomized to hormone replacement therapy have increased interest in other therapies for menopausal symptoms. Dietary supplements containing isoflavones are widely used as alternatives to hormonal therapies for hot flashes, but there is a paucity of data supporting their efficacy. OBJECTIVE: To compare the efficacy and safety of 2 dietary supplements derived from red clover with placebo in symptomatic menopausal women. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind, placebo-controlled trial of menopausal women, aged 45 to 60 years, who were experiencing at least 35 hot flashes per week. The study was conducted between November 1999 and March 2001 at 3 US medical centers and included women who were recently postmenopausal (mean [SD], 3.3 [4.5] years since menopause) experiencing 8.1 hot flashes per day. Women were excluded if they were vegetarians, consumed soy products more than once per week, or took medications affecting isoflavone absorption. INTERVENTION: After a 2-week placebo run-in, 252 participants were randomly assigned to Promensil (82 mg of total isoflavones per day), Rimostil (57 mg of total isoflavones per day), or an identical placebo, and followed-up for 12 weeks. MAIN OUTCOME MEASURE: The primary outcome measure was the change in frequency of hot flashes measured by participant daily diaries. Secondary outcome measures included changes in quality of life and adverse events. RESULTS: Of 252 participants, 246 (98%) completed the 12-week protocol. The reductions in mean daily hot flash count at 12 weeks were similar for the Promensil (5.1), Rimostil (5.4), and placebo (5.0) groups. In comparison with the placebo group, participants in the Promensil group (41%; 95% confidence interval [CI], 29%-51%; P =.03), but not in the Rimostil group (34%; 95% CI, 22%-46%; P =.74) reduced hot flashes more rapidly. Quality-of-life improvements and adverse events were comparable in the 3 groups. CONCLUSION: Although the study provides some evidence for a biological effect of Promensil, neither supplement had a clinically important effect on hot flashes or other symptoms of menopause.

Dietary Supplements↗
PubMed2004

Differential association of modifiable health behaviors with hot flashes in perimenopausal and postmenopausal women.

OBJECTIVE: To determine the association of modifiable factors, such as smoking, body mass index, and alcohol use, with hot flashes, and to ascertain whether the association with hot flashes varies by menopausal stage. DESIGN: A written survey completed by perimenopausal and postmenopausal women enrolling in a randomized, controlled trial of a menopause risk management program in 1999. Survey items included questions on demographics, health status, and health behaviors. SETTING: A Massachusetts-based health maintenance organization. PATIENTS/PARTICIPANTS: Female members, age 40 to 65, excluding women with chronic conditions precluding study participation, were randomly selected from an automated medical record system. MEASUREMENTS AND MAIN RESULTS: The majority of the 287 postmenopausal and 468 perimenopausal women participating in the study were white, college educated, and nonsmoking. Approximately 30% of both groups reported experiencing hot flashes. Separate multivariable logistic regression models were developed for perimenopausal and postmenopausal women to identify correlates of reporting any versus no hot flashes. After controlling for age, race, oral contraceptive use, hormone replacement therapy use, and depression, correlates of hot flashes in perimenopausal women were body mass index >/=25 kg/m(2) (odds ration [OR], 2.00; 95% confidence interval [CI], 1.28 to 3.12) and alcohol use of 1 to 5 drinks per week (OR, 0.52; 95% CI, 0.31 to 0.86). The only significant correlate of hot flashes in the postmenopausal population was high dietary fat intake (OR, 0.35; 95% CI, 0.15 to 0.81). CONCLUSION: Although study respondents were from similiar sociodemographic groups and received their health care in the same health maintenance organization, modifiable factors associated with hot flashes were different for perimenopausal and postmenopausal women.

Adult↗
PubMed2005

Body mass, estrogen levels, and hot flashes in midlife women.

OBJECTIVE: This study was undertaken to determine whether body mass index (BMI) is associated with hot flashes and whether the mechanism by which BMI increases the risk of hot flashes is by lowering estrogen levels. STUDY DESIGN: A case-control study was conducted among midlife women to examine risk factors for hot flashes. Cases were women who reported experiencing hot flashes (n = 353). Controls were women who reported never experiencing hot flashes (n = 258). Each participant completed a questionnaire and provided a blood sample for estrogen measurement. RESULTS: Compared with normal weight women, very obese women had significantly higher odds of hot flashes. The odds ratios remained elevated although attenuated when the hormone variables were added to the model. CONCLUSION: These results indicate that very obese women are at increased risk for hot flashes compared with normal weight women. Estrogen levels may partly explain this relationship; however, other mechanisms appear to be involved as well.

Age Factors↗
PubMed2004

The association between nocturnal hot flashes and sleep in breast cancer survivors.

This study examined the relationship between objectively measured nocturnal hot flashes and objectively measured sleep in breast cancer survivors with insomnia. Twenty-four women who had completed treatment for non-metastatic breast cancer participated. All were enrolled in a study of cognitive-behavioral treatment for chronic insomnia. Nocturnal hot flashes and sleep were measured by skin conductance and polysomnography, respectively. The 10-minute periods around hot flashes were found to have significantly more wake time, and more stage changes to lighter sleep, than other 10-minute periods during the night. Nights with hot flashes had a significantly higher percentage of wake time, a lower percentage of Stage 2 sleep, and a longer REM latency compared to nights without hot flashes. Overall, hot flashes were found to be associated with less efficient, more disrupted sleep. Nocturnal hot flashes, or their underlying mechanisms, should be considered as potential contributors to sleep disruption in women with breast cancer who report poor sleep.

Adult↗
PubMed2003

Gabapentin's effects on hot flashes in postmenopausal women: a randomized controlled trial.

OBJECTIVE: To evaluate whether treatment with the anticonvulsant gabapentin may be effective in reducing hot flash frequency and severity. METHODS: A randomized, double-blind, placebo-controlled trial was conducted in 59 postmenopausal women with seven or more hot flashes per day examining the effects of gabapentin 900 mg per day on hot flash frequency after 12 weeks of treatment. Subsequently, study patients were enrolled in a 5-week, open-label treatment phase, during which patients could increase the dose of gabapentin to 2,700 mg per day, if needed. RESULTS: After 12 weeks of double-blind treatment, intention-to-treat analysis showed that gabapentin 900 mg per day was associated with a 45% reduction in hot flash frequency and a 54% reduction in hot flash composite score (frequency and severity combined into one score) from baseline, compared with 29% (P =.02) and 31% (P =.01) reductions, respectively, for placebo. Four patients (13%) in the gabapentin group and one (3%) in the placebo group withdrew from the double-blind study because of adverse events. Fifteen patients (50.0%) in the gabapentin group reported at least one adverse event, compared with eight patients (27.6%) in the placebo group. Higher, open-label gabapentin dosing was associated with 54% and 67% reductions in hot flash frequency and composite score from baseline, respectively. CONCLUSION: Gabapentin is effective in reducing hot flash frequency and severity in postmenopausal women.

Acetates↗
PubMed2002

A pilot trial of paroxetine for the treatment of hot flashes and associated symptoms in women with breast cancer.

Abrupt onset of hot flashes poses a significant problem for women treated with chemotherapy for breast cancer. Alternatives to hormone replacement, such as the use of the selective serotonin re-uptake inhibitor (SSRI) paroxetine hydrochloride, are being explored as therapies for hot flashes in this patient population. The present study investigated the efficacy of paroxetine for the treatment of hot flashes and associated symptoms in women with breast cancer. This study included 13 patients who were seen in the Psychosocial Clinic at Moffitt Cancer Center. They were referred by their medical oncologist after reporting complaints of significant difficulty with hot flashes. Baseline questionnaires were completed and a structured diagnostic interview for clinical depression was conducted, all of which were repeated 5 weeks after the paroxetine 20 mg daily was started. Significant improvements were seen in the ratings of hot flash severity (P = 0.002). In addition, significant improvements were observed in general, emotional, and mental fatigue. Rates of clinically significant depressive symptomatology also decreased and sleep quality improved significantly as well. Finally, the incidence of clinical depression improved from 39% at baseline to 8% after treatment. These preliminary data suggest that the antidepressant paroxetine can be helpful in the treatment of hot flashes and associated fatigue, sleep disturbance, and depression in women with breast cancer treated with chemotherapy. Further controlled studies are needed to more fully evaluate the efficacy of the SSRIs for hot flashes in women with breast cancer.

Adult↗
PubMed2003

Risk factors for hot flashes in midlife women.

OBJECTIVE: To review the scientific literature pertaining to potential risk factors for hot flashes in midlife women. METHODS: Scientific publications reporting on risk factors for hot flashes were identified through a systematic Medline search and are summarized in this review paper. RESULTS: Although few studies have investigated risk factors for hot flashes in midlife women, consistent evidence suggests that smoking is associated with an increased risk for hot flashes. In addition, some studies suggest that other factors, such as hormone levels, body size, tubal ligation, surgical menopause, and race/ethnicity, may be associated with the occurrence of hot flashes. CONCLUSIONS: Future studies are needed to confirm previous findings and to identify additional risk factors for hot flashes. Such studies will increase our understanding of the etiology of hot flashes and may lead to better treatments and preventive measures for this condition.

Body Constitution↗
PubMed2002

A pilot study of magnetic therapy for hot flashes after breast cancer.

The purpose of this randomized placebo-controlled crossover pilot study was to evaluate the effectiveness and acceptability of magnetic therapy for hot flashes among breast cancer survivors. Participants completed a 24-hour baseline hot-flash monitoring session, wore the magnetic devices or placebo for 3 days, completed an after-treatment hot-flash monitoring session, experienced a 10-day washout period, and then crossed over to the opposite study arm. Magnetic devices and placebos were placed on 6 acupressure sites corresponding to hot-flash relief. Complete data were available from 11 survivors of breast cancer. Results indicated magnetic therapy was no more effective than placebo in decreasing hot-flash severity, and contrary to expectations, placebo was significantly more effective than magnets in decreasing hot-flash frequency, bother, interference with daily activities, and overall quality of life. Implications for clinical practice and future research include the need to explore alternative interventions aimed at alleviating hot flashes in this population.

Aged↗