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PubMed1989

Biophysical and endocrine-metabolic changes during menopausal hot flashes: increase in plasma free fatty acid and norepinephrine levels.

Thermocutaneous, vascular, metabolic and hormonal changes were investigated during 11 hot flashes from 6 postmenopausal women. The first detectable change was an increase in finger blood flow with a concomitant enhancement of skin conductance. The increase in skin conductance was followed rapidly by a sharp rise in finger temperature. The main endocrine-metabolic changes associated with the above phenomena were a sharp increase in plasma free fatty acids (approximately 65%), norepinephrine (approximately 100%) and LH (approximately 20%) levels. Plasma glucose and cortisol tended to be increased but did not reach statistical significance; on the other hand, plasma insulin, glucagon, growth hormone, epinephrine and dopamine remained unchanged.

Adult↗

PubMed1995

Cardiac sarcoplasmic reticulum phosphorylation increases Ca2+ release induced by flash photolysis of nitr-5.

Effects on Ca(2+)-induced Ca2+ release due to phosphorylation of sarcoplasmic reticulum (SR) proteins were investigated in isoproterenol-treated saponin-permeabilized trabeculae from rat ventricles. In these experiments, Ca2+ release from the SR was induced by a rapid change in concentration of free Ca2+ (ie, trigger Ca2+) achieved by flash photolysis of nitr-5, and the amount of Ca2+ released was assessed by measuring isometric tension. Ca2+ uptake by the SR was more rapid, and the amount of Ca2+ released by a given concentration of trigger Ca2+ was greater in isoproterenol-treated trabeculae compared with control trabeculae. However, under the same conditions of Ca2+ loading, the amplitudes of caffeine-elicited tension transients in control trabeculae were similar to those in isoproterenol-treated trabeculae, suggesting that the Ca2+ available for release was similar in the two cases. Control experiments showed that there were no significant differences in Ca2+ sensitivity of tension between isoproterenol-treated and control trabeculae. Also, application of alkaline phosphatase to trabeculae that had previously been treated with isoproterenol returned SR Ca2+ release to control levels. We conclude that the greater release of Ca2+ in isoproterenol-treated trabeculae in response to a given concentration of trigger Ca2+ is due to phosphorylation of SR proteins, most likely the Ca2+ release channel.

Alkaline Phosphatase↗

PubMed2004

Paired-flash identification of rod and cone dysfunction in the diabetic rat.

PURPOSE: To investigate the onset of retinal neural dysfunction in the streptozotocin (STZ)-induced diatebic rat. METHODS: A cohort of 20 Sprague-Dawley rats were randomly assigned to treatment (STZ 50 mg/kg, n = 10) and control (citrate buffer, n = 10) groups and observed for 12 weeks. Diabetes was confirmed by blood glucose (>15 mmol/L) and HBA(1c) (>7.0%). Treated animals received 2 to 3 U insulin daily. Retinal function was monitored using paired-flash electroretinograms (ERGs) at baseline and various time points between 2 days and 12 weeks after treatment, to allow isolation of rod and cone components. Protocols compared photoreceptor and inner retinal responses (rod and cone) at each time point. RESULTS: Losses in the function of rod photoreceptors and the inner retina were seen 2 days after STZ injection, with recovery in some components by 4 weeks and a secondary loss of function at 12 weeks. Some inner retinal responses (cone response and rod oscillatory potentials (OPs) remained consistently depressed over the entire 12 weeks. CONCLUSIONS: Retinal neural dysfunction was observed as early as 2 days after STZ injection. These acute changes reflect either STZ toxicity or hyperglycemia as a result of pancreatic compromise. Consistent loss over the 12 weeks of the cone response and OPs suggests a vulnerability of the inner retina to STZ-related effects. The 12-week losses in function of retinal neurons are consistent with a generalized diabetic neuropathy, since impaired function developed simultaneously in both inner and outer retinal neurons.

Animals↗

PubMed1991

Visual evoked potentials in dementia: selective delay of flash P2 in probable Alzheimer's disease.

The flash visual evoked potential P2 component is delayed in etiologically mixed groups of demented patients compared to healthy controls or nondemented patients. This study compared patients meeting both DSM-III-R criteria for dementia and NINCDS-ADRDA criteria for probable Alzheimer's disease (AD) with healthy elderly controls and found the P2 delay in the probable AD group. Additional comparisons found no evidence of a P2 delay in demented unlikely AD patients. These results suggest that earlier findings of a delayed P2 in etiologically mixed demented groups may have been due to inclusion of AD patients.

Aged↗

PubMed1997

Prevention of flash fires during facial surgery performed under local anesthesia.

As more surgical procedures are being performed under local anesthesia and intravenous sedation, complications associated with these techniques are more likely to be experienced. We report a case of an intraoperative flash fire that occurred while supplemental oxygen was being used in this scenario. A literature review and suggestions for prevention of this complication are discussed.

Accidents↗

PubMed1998

Flash pump dye laser treatment of laryngeal papillomas.

To evaluate the feasibility and safety of the flash pump dye (FPD) laser for the treatment of laryngeal papillomas, we performed a prospective nonrandomized trial comparing FPD and carbon dioxide (CO2) laser treatment of laryngeal papillomas in a tertiary care children's hospital. Nine patients from 2 to 20 years of age with severe recurrent laryngeal papillomas were enrolled in the study. All patients underwent CO2 laser debulking of papillomas on the left hemilarynx, with 8 W continuous or pulsed energy. The right hemilarynx was treated with the FPD laser with 12 to 77 pulses at 8 to 12 J, through a custom-designed 90 degrees firing fiber. An end point of blanching and purpura of the papillomas was used. The main outcome measures were the safety and ease of operation with the FPD laser, and decreased papilloma size based on visual inspection at 2 weeks postoperative and at the next laser procedure. Seven patients were irradiated I time with an FPD laser, and 2 patients 2 times. No intraoperative complications were noted. One patient developed early postoperative stridor. No patients described more discomfort, and 5 patients described their voice as being the same as or better than it was after prior CO2 laser procedures. Five patients had a 90% or more decrease in size of papillomas on the FPD-irradiated side 2 weeks postoperatively. Three patients had approximately a 50% reduction. A treatment effect was noted in all patients, and was similar to the results noted on the CO2 laser-treated side. Early results with FPD laser treatment of laryngeal papillomas suggest the protocol is relatively safe and feasible. Long-term results are pending. Because the FPD laser coagulates rather than vaporizing tissue, potential advantages may include decreased scarring relative to CO2 laser treatment, and improved patient and operator safety.

Adolescent↗

PubMedDate not supplied

A neurotoxicity assessment of high flash aromatic naphtha.

Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide-boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 Aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent also known as High Flash Aromatic Naphtha (HFAN). A program was initiated to assess the toxicological properties of HFAN since there may be human exposure, especially in the workplace. The current study was conducted to assess the potential for neurotoxicity in the rat. Adult male Sprague-Dawley rats of approximately 300 grams body weight, in groups of twenty, were exposed by inhalation to HFAN for 90 days at concentrations of 0, 100, 500, and 1500 ppm. During this period the animals were tested monthly for motor activity and in a functional observation battery. After three months of exposure, for 6 hours/day, 5 days/week, 10 animals/group/sex were sacrificed and selected nervous system tissue was examined histopathologically. No signs of neurotoxicity were seen in any of the evaluated parameters, nor was there evidence of pathologic changes in any of the examined tissues.

Administration, Inhalation↗

PubMed2002

Can police car colored flash light induce electroencephalographic discharges and seizures?

AIM: To explore the epileptogenic potential of a newly introduced police car flash light device (930 Heliobe Lightbar). METHODS: A 930 Heliobe Lightbar was installed in the EEG laboratory. Thirty patients with known epilepsy, 30 subjects with chronic headache who were otherwise healthy and 15 healthy volunteers were examined. RESULTS: All the subjects signed an informed consent and underwent an EEG during which photostimulation was performed with the standard stroboscope and later with the Police lightbar. In all 75 examined the lightbar did not induce clinical or electrographic seizures. In a single patient with epilepsy the lightbar enhanced epileptiform activity induced by standard photic stimulation. CONCLUSION: In this study the new Police lightbar was found to be non-epileptogenic.

Adolescent↗

PubMed2006

Human sensory-evoked responses differ coincident with either "fusion-memory" or "flash-memory", as shown by stimulus repetition-rate effects.

BACKGROUND: A new method has been used to obtain human sensory evoked-responses whose time-domain waveforms have been undetectable by previous methods. These newly discovered evoked-responses have durations that exceed the time between the stimuli in a continuous stream, thus causing an overlap which, up to now, has prevented their detection. We have named them "A-waves", and added a prefix to show the sensory system from which the responses were obtained (visA-waves, audA-waves, somA-waves). RESULTS: When A-waves were studied as a function of stimulus repetition-rate, it was found that there were systematic differences in waveshape at repetition-rates above and below the psychophysical region in which the sensation of individual stimuli fuse into a continuity. The fusion phenomena is sometimes measured by a "Critical Fusion Frequency", but for this research we can only identify a frequency-region [which we call the STZ (Sensation-Transition Zone)]. Thus, the A-waves above the STZ differed from those below the STZ, as did the sensations. Study of the psychophysical differences in auditory and visual stimuli, as shown in this paper, suggest that different stimulus features are detected, and remembered, at stimulation rates above and below STZ. CONCLUSION: The results motivate us to speculate that: 1) Stimulus repetition-rates above the STZ generate waveforms which underlie "fusion-memory" whereas rates below the STZ show neuronal processing in which "flash-memory" occurs. 2) These two memories differ in both duration and mechanism, though they may occur in the same cell groups. 3) The differences in neuronal processing may be related to "figure" and "ground" differentiation. We conclude that A-waves provide a novel measure of neural processes that can be detected on the human scalp, and speculate that they may extend clinical applications of evoked response recordings. If A-waves also occur in animals, it is likely that A-waves will provide new methods for comparison of activity of neuronal populations and single cells.

Acoustic Stimulation↗

PubMed1991

Postnatal development of flash visual evoked potentials in the jaundiced Gunn rat.

In this study, the postnatal development of flash visual evoked potential (VEP) has been monitored in the jaundiced (jj) Gunn rat model of neonatal hyperbilirubinemia to determine whether this evoked response is affected by bilirubin-induced neurotoxicity. VEP could first be recorded at 16 d of age. The jj rats exhibited prolonged wave latencies and lower wave amplitudes during the 3rd wk of postnatal life, when compared with their nonjaundiced littermates. There was no correlation at 21 d of age between VEP parameters and either bilirubin levels or body weight. About one third of the jj animals died between 21 and 28 d of age. The average VEP wave latencies at 21 d of age of the rats who were to die was prolonged compared with those of rats who survived till at least 28 d of age. Thus, the latency of VEP waves at the age of 21 d appears to be related to the further outcome of jj Gunn rats. Although wave amplitudes were lower in jj as compared with nonjaundiced 21-d-old animals, there were no amplitude differences between the jj rats who would die and those who would survive during the 4th wk of life. These findings may contribute to the understanding of the pathogenesis of bilirubin encephalopathy in the neonatal period.

Age Factors↗

PubMed1984

Further delineation of hypothalamic dysfunction responsible for menopausal hot flashes.

An association exists between pulsatile LH release and hot flashes (HFs). To further delineate the hypothalamic mechanism(s) responsible for HF, the basal levels and pulsatile release of LH, FSH, estradiol, and estrone and the rate of occurrence of HFs (measured objectively) were evaluated in patients with a defect of GnRH secretion [isolated gonadotropin deficiency (IGD)], patients with abnormalities of afferent input to GnRH neurons [hypothalamic amenorrhea (HA)], and postmenopausal women with severe HFs. Patients with IGD had received estrogens, which were discontinued before study. Patients with HA had experienced regular menses before disease onset, which followed emotional stress or weight loss. Studies were limited to HA patients with estrogen levels in the postmenopausal range. Pulsatile LH release was absent in patients with IGD and was absent or greatly reduced in women with HA. Objectively measured and subjectively experienced HFs occurred in IGD but not in HA patients. These results suggest that HFs are not an obligatory consequence of low endogenous estrogen levels and that the absence of episodic LH and GnRH release (IGD) does not influence the occurrence of HFs. It is possible that the dysfunction of afferent input to GnRH neurons in HA somehow prevents HFs in these women with low endogenous estrogen secretion.

Adult↗

PubMed1985

Treatment of hot flashes with transdermal estradiol administration.

A randomized prospective double blind study was performed to assess the ability of a transdermal therapeutic system (TTS) delivering estradiol (E2) to suppress hot flashes (HFs) in symptomatic postmenopausal women. Patients were given placebo or E2 in four doses for a 20-day period, and serum gonadotropin and estrogen levels and the occurrences of HFs were measured. Administration of placebo had no measurable effect on either estrogen or gonadotropin levels or the occurrence of HFs. A dose-response relationship was found between the rate of E2 administered and the circulating level of E2, with 25, 50, 100, and 200 micrograms/24 h dosages raising the mean E2 concentrations from mean baseline levels of 5-8 pg/ml to 18, 38, 73, and 100 pg/ml, respectively. Estrone levels also increased with TTS application, but to a lesser extent than did E2 levels. Dose-response reductions of FSH and LH with increasing amounts of E2 administration occurred, but gonadotropin levels were not lowered in any of the patients into the ranges found in premenopausal women. TTS application significantly suppressed the occurrence of HFs at the 50 micrograms/24 h dosage and higher. A significant negative correlation (r = 0.6045; P less than 0.001) between E2 levels and the rates of occurrence of HFs was found during hormone administration. Based on this regression, 50% and 100% reductions of HFs should occur at 61 and 122 pg/ml E2. These data indicate that the transdermal delivery of E2 with these systems significantly reduced the occurrence of HFs and allowed definition of the therapeutic range of hormone replacement in terms of lost ovarian function, as reflected by circulating E2 levels.

Administration, Topical↗

PubMed1990

Incendiary potential of the flash-lamp pumped 585-nm tunable dye laser.

The recently introduced pulsed flash-lamp pumped tunable dye laser is used to treat cutaneous port-wine stains. In our practice, infants and children receive general anesthesia for these brief, yet painful, treatments. Because the flammability of this laser has not been reported and because we administer supplemental oxygen and nitrous oxide, we analyzed the incendiary potential of this laser by measuring the flammability of gauze and Telfa strips, hair, clear plastic face masks and tracheal tubes, and green nasal cannulae in 21%-100% oxygen and in nitrous oxide at laser energies between 6.0 and 10.0 J/cm2. (Our clinical range is 6.0-7.0 J/cm2.) In room air, gauze, Telfa, masks, and tubes did not ignite; only gauze ignited at high energy in 100% oxygen. Hair ignited in room air only when struck repeatedly at high energy, but easily ignited in 100% oxygen. Wetting hair with saline prevented ignition in room air and decreased flammability in supplemental oxygen. Green nasal cannulae prongs were extremely flammable in oxygen. Caution should be taken when using supplemental oxygen/nitrous oxide during treatment with the tunable dye laser.

Facial Neoplasms↗

PubMed1995

Technical note: dynamic analysis of the pharynx during swallowing using Turbo-FLASH magnetic resonance imaging combined with an oral positive contrast agent--a preliminary study.

Serial images of the swallowing motions of 10 healthy volunteers were taken using the Turbo-fast low angle shot (FLASH) magnetic resonance (MR) imaging sequence, while the subject swallowed an oral contrast agent containing ferric ammonium citrate. In all cases, the flow of the contrast agent and the motion of the organs in the oral cavity and the pharynx during swallowing could be observed. High-speed MR imaging combined with an oral positive contrast agent has the potential to evaluate accurately swallowing motion.

Adult↗

PubMed2002

The Sileye-3/Alteino experiment for the study of light flashes, radiation environment and astronaut brain activity on board the International Space Station.

In this work we describe the instrument Sileye-3/Alteino, placed on board the International Space Station in April 2002. The instrument is constituted by an Electroencephalograph and a cosmic ray silicon detector. The scientific aims include the investigation of the Light Flash phenomenon, the measurement of the radiation environment and the nuclear abundance inside the ISS and the study of astronaut brain activity in space when subject to cosmic rays.

Astronauts↗

PubMed2003

Laser action from two dipyrrinone dyes under flash-lamp pumping.

Two quasi-aromatic compounds, namely, two dipyrrinone dyes (Xanthoglow and Kryptoglow), exhibited strong fluorescence. Therefore they were tested for laser action under flash-lamp pumping. These two dyes outperformed Coumarin 540A and exhibited a high degree of photostability when dissolved in 1,4-dioxane. However, in all other solvents used, considerable photodecomposition was observed.

Journal Article↗

PubMed2006

Flash light detection and ranging range accuracy limits for returns from single opaque surfaces via Cramer-Rao bounds.

A Cramer-Rao lower bound on the range accuracy obtainable by a Flash light detection and ranging (LADAR) system receiving a return from a single surface in the instantaneous field of view of each detector is developed and verified with experimental data. The bound is compared to the performance of a new algorithm and that of a matched filter receiver by using both simulated and measured LADAR data. The simulated data are used to show that the estimator is nearly unbiased and efficient for systems that match the negative paraboloid model used in its derivation. It is found that the achievable range accuracy for the LADAR system and for the target geometry used to collect the measured data is of the order of 2.5 in. while the bound predicts a range accuracy limit of approximately 0.6 in.

Journal Article↗

PubMed1981

Concurrent birefringence and forward light-scattering measurements of flash-bleached rod outer segments.

A microretardometer--nephelometer was constructed to measure birefringence and forward-direction light scattering concurrently in single retinal rod outer segments (ROS). The relative contributions of light-induced birefringence and light-scattering changes to observed far-red transmission changes measured normal to the cell axis were evaluated in isolated, whole, flash-bleached ROS. No light-scattering transients were found corresponding to the previously reported rapid birefringence loss associated with the metarhodopsin I lead to metarhodopsin II reaction even under conditions in which such a light-scattering change has been reported for outer-segment fragments.

Birefringence↗