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At least 541 records · Page 30Linked to original sources
PubMed1988

Pathological hyperprolactinemia suppresses hot flashes in menopausal women.

Hyperprolactinemia impairs pituitary-gonadal function in young women, but its effect in menopausal women is not known. The purpose of this report is to describe the effect of hyperprolactinemia on gonadotropin secretion and hot flashes in menopausal women before and after treatment with a dopamine agonist. We studied two such women with prolactinomas. Both had plasma LH and FSH levels in the range found in premenopausal women and no hot flashes. Treatment with bromocriptine was associated with normalization of plasma PRL levels, elevation of plasma gonadotropin levels, and the onset of menopausal hot flashes in both patients. We conclude that hyperprolactinemia can inhibit the augmented gonadotropin secretion that occurs in postmenopausal women and prevent hot flashes.

Adenoma↗
PubMed2006

Age-associated changes of flash visual evoked potentials in dogs.

Age-associated changes of visual evoked potentials by flash stimulation (flash VEP) were evaluated in 53 beagle dogs aged from 1- to 15-year-old. Among the components of flash VEP consisted of 3 positive (P1, P2 and P3) and 2 negative (N1 and N2) peaks by 150 msec, the latency of P2 and the later peaks (N2 and P3) were significantly delayed with aging. Both amplitudes of the P2-N2 and N2-P3 also showed a significant correlation with aging. The flash VEP is considered to be an available and useful technique to evaluate not only for visual pathway, but also some disturbance of neurological functions, like as those reported in demented human.

Age Factors↗
PubMed1987

Some properties of the double-flash illusion.

When a field of light (an inducing field) is extinguished, and a subsequent probe pulse is presented (5-msec duration, interstimulus interval of 80-320 msec), the single probe pulse appears to be a double flash. We measured the frequency of seeing this double-flash illusion when it was induced by high-contrast flickering fields. The illusion is dependent on inducer-field frequency, showing a major peak and, for some interstimulus intervals, subpeaks. There are notable interobserver differences in the frequency location of the peaks. We evaluated whether the results represented the transient response of a mechanism analogous to a single-harmonic oscillator. A second experiment compares the threshold illuminance for detecting the probe pulse with the illuminance above threshold required to see the double-flash illusion. The illuminance required for a double-flash threshold is high, being 7-20 times the illuminance required for pulse detection.

Adult↗
PubMedDate not supplied

Responses of barnacle photoreceptors to high energy flashes of short duration.

In chromatic adapted barnacle median and lateral photoreceptors the two stable states of the photopigment (rhodopsin R and metarhodopsin M) were interconverted with intense, colored light flashes of 1 ms duration. Only after conversion of the red adapted photoreceptor in K+-Ringer solution with an intense flash the negative early receptor potential, ERP (of R) gradually appeared detected with an indicator flash. For the opposite conversion (blue adapted, R leads M) the gradual appearance of the positive ERP (M) was not measurable in the same time span. In artificial seawater all flash stimuli yielded--irrespective of color--the transient component of the late receptor potential (LRP). ERP results for the lateral photoreceptor are discussed in view of an existing kinetic model and an attempt is made to give an explanation which covers the new LRP transient and ERP results for both types of photoreceptor (appendix).

Animals↗
PubMed1975

A further study on fast and slow principal cells of rat lateral geniculate body: an analysis of flash-evoked responses.

In the lateral geniculate body (LGB) of urethane-anesthetized and Flaxedil-immobilized rats, unit responses of principal cells (P-cells) were recorded by using flash stimulation of the eyes. By measuring response latencies to electrical stimulation of the optic tract, all P-cells were classified into the fastor slow group according to the criterion established by Fukuda. Flash-evoked unit responses consisted of the two kinds of discharges, i.e. the early discharge (ED) with latencies less than 100 msec and the late discharges of spike burst (LDs) often recurring twice or more (LD1, LD2 and so on). Cells' firings were suppressed during the interval between ED and LD1 and those between successive LDs. The ED- and LD1-latencies, measured in dark with strong flashes, were shorter in the fast cells than in the slow one. The interval between ED and LD1 was shorter in the fast cells than in the slow ones. It was common to the both types of P-cells that as flash intensity was reduced, the ED-latency increased and the LD1-latency decreased. However, the ED-LD1 interval remained shorter in the fast cells than in the slow ones. Upon shifting from dark to light, the LD1-latency markedly increased or decreased in the slow cells, whereas such was not seen in the fast cells. These findings seem to provide a further support for the classification of P-cells into the fast and slow types.

Animals↗
PubMed2006

Using macromedia flash for electronic presentations: a new alternative.

OBJECTIVE: This article provides a step-by-step tutorial for creating electronic presentations using Macromedia Shockwave Flash, one of the recommended file formats for many radiologic society annual meetings, including the American Roentgen Ray Society (ARRS). CONCLUSION: Although Flash and PowerPoint can be used for creating presentation slide shows, Flash is more appropriate for integrating and delivering animations for Internet applications such as radiologic electronic presentations. For this reason, detailed step-by-step instructions for creating Flash slide shows with common features such as text, images, arrows, buttons, movie loops, and transitions are provided. The approach used in this article is particularly appropriate for academic radiologists who have basic PowerPoint skills but lack programming experience.

Computer Graphics↗
PubMed2004

Pathological proof of cellular death in radiofrequency ablation therapy and correlation with flash echo imaging--an experiment study.

The aims of this study were to clarify the geographic distribution of complete cell death in the radiofrequency ablated area in a porcine liver experiment, and to evaluate the efficacy of ultrasonography using contrast media in detecting the area of Radiofrequency-induced cell death. Radiofrequency ablation was performed at 3 sites in each liver in seven swine with a RF2000TM radiofrequency generator using an expandable type needle electrode. The ablation area was investigated histologically by Hematoxylin-Eosin staining and NADH staining. The area of radiofrequency-induced cell death was correlated to the ultrasonographic findings using contrast media, by means of contrast harmonic imaging, flash echo imaging-subtraction and flash echo imaging-power Doppler. The ablation area showed three distinct regions. Although the HE staining did not indicate necrosis, the NADH staining showed a complete loss of cellular activity in the inner and middle layers of the ablation area. However, in the outer layer cells displaying cellular integrity were intermingled with the necrotic cells, indicating that some of the cells in this layer had a chance to survive. Further, in some cases the outer layer of the ablated area had irregular margins. The flash-echo power-doppler images were accurately correlated in size and shape to the pathologically proved region of complete cell death in the radiofrequency-induced lesions. In the marginal part of the radiofrequency ablation area, cell death was incomplete. Flash echo imaging-power doppler was a useful and sensitive real time imaging technique for accurate evaluation of the region of complete cell death.

Animals↗
PubMed2000

Evaluation of flash echo imaging of the canine gastrointestinal tract.

Although it is important to assess gastrointestinal blood flow, no generally useful, noninvasive assessment method has been established. Harmonic flash echo imaging, which is an intermittent second harmonic imaging technique, has recently become available to evaluate blood flow. We investigated the usefulness of harmonic flash echo imaging in the assessment of the gastrointestinal tract, and we used this technique to study the effect of nicotine on small bowel blood flow. Harmonic flash echo imaging was performed at the beginning of intravenous injection of a contrast agent. It was also performed on the small bowel immediately before and 10 min after nicotine administration to evaluate blood flow. Gastric and small bowel walls were clearly enhanced on the primary images. Small bowel enhancement, which is regarded as transmural blood flow, significantly decreased after nicotine administration. Harmonic flash echo imaging appears to be useful in the assessment of the transmural blood flow in the gastrointestinal wall.

Animals↗
PubMed1985

Quality control in the "flash" process.

This article has briefly discussed the three basic types of sterilization monitoring systems--mechanical, chemical, and biological. Mechanical indicators help tell you that the sterilizer is working. Chemical indicators provide you with immediate information in each "flash" load that the conditions necessary for steam sterilization were present. Biological indicators tell you that microorganisms were killed. For maximum assurance that the conditions necessary for steam sterilization are present and that non-sterile instruments are not inadvertently used, each "flash" sterilizer should be monitored daily with biological indicators and each "flash" load with chemical indicators. This quality control monitoring program should give the O.R. staff confidence that their "flash" sterilization process is working.

Central Supply, Hospital↗
PubMed2002

Pigeons presented with sequences of light flashes use behavior to count but not to time.

On randomly ordered trials, pigeons were presented with either a blue or a white key that flashed red for 200 ms at a fast (2 flashes/s), medium (1 flash/s), or slow (0.5 flashes/s) rate. The blue key signaled a fixed-interval (FI) schedule in which the first response after 20 s was reinforced, and the white key signaled a fixed-number (FN) schedule in which the first response after 20 flashes was reinforced. In Experiments 1 and 2, pigeons showed depressed responding to the flash on FI-cued trials and accelerated responding to the flash on FN-cued trials. When the response key was periodically blacked out in Experiments 3 and 4, counting but not timing was eliminated.

Animals↗
PubMed1977

Role of nuclear stars in the light flashes observed on Skylab 4.

The astronauts on Skylab 4 observed bursts of intense visual light-flash activity when their spacecraft passed through the portion of the earth's inner trapped radiation belt known as the South Atlantic Anomaly (SAA). Two experimental sessions were carried out on board Skylab 4 under the auspices of Pinsky et al. who compare the flash rates with the measured flux of Z > or = 1 particles that would pass through the astronaut's eyes. They concluded that the flash rates, which became as great as 20/min, were anomalously high. We explored a number of alternative explanations for the anomalous flash rates that would be consistent with the accepted SAA flux values and the laboratory data on particle induced visual sensations and found that when one includes the effect of nuclear interactions in and near the retina which result in star formation (the emission of slow protons, neutrons and alpha particles form the nucleus in an evaporation-like process) the apparent anomaly is removed.

Aerospace Medicine↗
PubMed1975

Effect of preconditioning visual stimulus duration on visual-evoked responses to a subsequent test flash in Down's syndrome and nonretarded individuals.

Visual-evoked responses to a visual test flash preceded by three different durations of a visual conditioning flash having the same intensity and form were recorded from 8 Down's syndrome subjects and 9 nonretarded CA-matched control subjects. Both groups showed a significant decrease in visual-evoked response perimeters to the test flash as the duration of the visual conditioning flash increased from 1 to 100 msec. For the 1000-msec condition, perimeters of Down's syndrome subjects showed a significant increase, and this was significantly greater than the nonretarded group. These results suggest that Down's syndrome individuals have deficits in their neural processing of sensory information.?23Author

Adolescent↗
PubMed1990

Effect of spectral flash on readaptation time.

The effects of an adapting flash of different colors on human vision were investigated with various flashes and target luminances. The readaptation time (RAT) was measured using optokinetic nystagmus elicited by a projected moving striped pattern in a hemisphere. The RATs were recorded from 26 subjects with a multichannel pen recorder. Two target luminances (1.1 X 10(-5) cd/m2 and 2.6 X 10(-5) cd/m2) and 12 flash wavelengths (449 nm, 456 nm, 468 nm, 477 nm, 498 nm, 502 nm, 520 nm, 565 nm, 580 nm, 591 nm, 622 nm, and 703 nm) were used. A spectral RAT curve was obtained, which showed that the chromatic response of RAT follows this order: green greater than blue greater than yellow greater than red. A larger influence of the variation of the target luminance on the RAT was demonstrated at shorter wavelengths. The results also showed that the energy density of the flash has a larger variation with the RAT in blue and green than in red.

Adaptation, Ocular↗
PubMed1988

Quantification and calibration of flash stimuli in clinical research.

Despite the relatively wide use of flash-type stimuli in VEP studies, no universally accepted standards or methods of measurement for these stimuli are in existence. Several methods have been described for the determination of flash-intensities, however, the majority of these methods are not sufficiently rigorous, or are based on overly optimistic assumptions on the ideal nature of flash-stimulators. We describe here a simple method for the determination of flash-stimulus energies and absolute peak intensities. Our method does not require specialized optometric instrumentation, and should be readily adaptable to any modern laboratory.

Calibration↗
PubMed1983

Three types of blink reflex evoked by supraorbital nerve, light flash and corneal stimulations.

Three types of blink reflex were evoked by 1) supraorbital nerve stimulation, 2) light flash stimulation and 3) corneal touch. The blink reflex response was recorded simultaneously for both eyes by electromyography of the orbicularis oculi muscles of the lower eyelid. After supraorbital nerve stimulation, ipsilateral early response (R1) and bilateral late responses (R2) were demonstrated. The light flash stimulation evoked the photic early and late responses. The latency times of the R1, R2 and the photic early responses were determined in 22 normal subjects. The corneal touch was exactly timed using a new device and the latency time of the corneal blink reflex was determined. The latency of the ipsilateral corneal blink reflex was significantly shorter than that of the contralateral reflex. The blink reflexes by supraorbital nerve stimulation and light flash were studied concurrently in 7 patients with neurological disorders of vascular origin. The photic reflex was disturbed by bilateral occipital lobe lesions and also by affection of the rostral midbrain. The reflexes were not affected by lesions in the medial longitudinal fasciculus but were disturbed by widespread brainstem lesions of Foville syndrome. Clinical significance of a combined use of the supraorbital nerve and light flash stimulation was emphasized.

Adult↗
PubMed1982

Estrogen levels in postmenopausal women with hot flashes.

Following menopause, some women are troubled by hot flashes (episodes of flushing and perspiration), whereas others do not experience the symptom. To determine whether the extent of estrogen deficiency influences the occurrence of the disturbance, the authors measured the levels of estradiol (E2), estrone (E1), and sex-hormone binding globulin (SHBG), and the percent and total non-SHBG-bound E2 in 24 women with frequent hot flashes and 24 women who had never experienced the symptom. Significantly lower levels of E2 (P less than .002), E1 (P less than .05), percent non-SHBG E2 (P less than .05), and total non-SHBG-bound E2 (P less than .01) were found in the symptomatic women. Similar differences were confirmed in 18 subject pairs matched for age, years since menopause, and presence or absence of ovaries. The finding of a significantly (P less than .05) lower percent ideal body weight in the women with hot flashes suggests that the known effects of body weight on the rate of extraglandular estrogen production and the level of SHBG in postmenopausal women may be important variables determining the occurrence of hot flashes.

Age Factors↗
PubMed1980

Carotenoid transformations underlying the blue absorbance change in flashed leaves during the induction of oxygen evolution.

The blue absorbance change occurring in flashed bean (Phaseolus vulgaris L.) leaves when exposed to continuous light (first observed by Strasser; Strasser, R.J. (1973) Arch. Int. Physiol. Biochem. 81, 935--955) is caused by the conversion of the following xanthophylls: violaxanthine leads to antheraxanthine leads to zeaxanthine. This conclusion is derived from the simultaneous occurrence of both reactions: (a) In flashed leaves, blue absorbance change and xanthophyll conversion take place under strong (2 mW . cm-2) but not under weak (0.02 mW . cm-2) white light. (b) In chloroplasts isolated from flashed leaves, the blue absorbance change occurs in the dark under conditions that also induce the xanthophyll conversion. (c) Blue absorbance change and xanthophyll conversion are both inhibited by dithiothreitol. In addition, the light-induced blue absorbance change is reversed in the dark if aerobic conditions are maintained, i.e. under conditions that in normal leaves favor the reversal of the above reaction sequence. The significance of the xanthophyll conversion is discussed in relation to other phenomena occurring in flashed leaves after exposure to continuous illumination.

Ascorbic Acid↗
PubMed1995

The hot flash: pathophysiology and treatment.

Hot flashes are the most frequent somatic complaint of women going through the menopause. Although the exact pathophysiology of the hot flash remains unknown, it appears to be related to an alteration in the set point of the hypothalamic thermoregulatory center. With the withdrawal of estrogen, some event parallel to the release of GnRH (and subsequent release of LH) causes a decrease in the set point of the thermoregulatory center. The hot flash, with its characteristic sweating and vasodilation, represents the attempt to decrease the body core temperature and restore equilibrium. Estrogen therapy reliably treats hot flashes in the majority of women in addition to its proven beneficial effect on heart disease and osteoporosis. It is rare that health care providers can so reliably and safely positively impact on a patient's symptoms and overall health.

Body Temperature Regulation↗