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PubMed2006

Evaluating use of flash sterilization in the OR with regard to postoperative infections.

This article describes a quality improvement project that examined postoperative infection rates for 100 surgical procedures in which a total of 121 flash sterilizations were performed and determined the costs of treating the postoperative infections compared to the cost of purchasing additional instruments. The post operative infection rate on physical examination was 3%, and the overall cost of diagnosing and treating the postoperative infections was found to be lower than the cost of purchasing additional instruments. To minimize use of flash sterilization, the hospital has added additional surgical instrument inventory and expanded flash sterilization education requirements for staff members.

Cost-Benefit Analysis↗
PubMed2003

Unilateral leukocoria in off axis flash photographs of normal eyes.

PURPOSE: To describe an optical phenomenon producing leukocoria in off axis flash photographs of children who have a normal ophthalmic examination. DESIGN: Observational case series. METHODS: Description of three otherwise well children who presented to a pediatric ophthalmologist with unilateral leukocoria seen in flash photographs. The children underwent a full ophthalmic examination, including dilated fundus examination. RESULTS: All ophthalmic examinations were normal. The photographs were all found to be approximately 15 degrees off axis with the leukocoria seen in the eyes where the flash illuminated the nasal retina. CONCLUSIONS: Leukocoria can be seen in normal eyes when the child is not fixing directly on the camera. That is due to reflection off the optic nerve head.

Artifacts↗
PubMed1994

Relationship between floaters, light flashes, or both, and complications of posterior vitreous detachment.

We examined biomicroscopically the vitreous and retinal conditions of 902 consecutive symptomatic eyes (785 patients) to ascertain the relationship between floaters, light flashes, or both, and complications of posterior vitreous detachment. Of 785 patients, 785 symptomatic eyes were divided as follows: group 1, 342 eyes with floaters alone; group 2, 240 eyes with floaters and light flashes; and group 3, 203 eyes with light flashes alone. We also studied 636 asymptomatic fellow eyes. The prevalence of posterior vitreous detachment was significantly higher in groups 1 (138 of 342, 40%), 2 (214 of 240, 89%), and 3 (137 of 203, 67%) than in the asymptomatic eyes (127 of 636, 20%), in group 2 than in groups 1 and 3, and in group 3 than in group 1 (P = .01). The prevalence of retinal breaks in eyes with posterior vitreous detachment was 5% (seven of 138), 13% (27 of 214), 12% (16 of 137), and 4% (five of 127) in groups 1, 2, 3, and the asymptomatic eyes, respectively; the prevalence was significantly higher in groups 2 and 3 than in asymptomatic eyes (P = .02 and P = .04) and group 1 (P = .04 and P = .05). The prevalence of vitreous hemorrhage in eyes with retinal breaks was 71% (five of seven), 70% (19 of 27), and 6% (one of 16) in groups 1, 2, and 3, respectively. Of 117 patients with bilateral symptoms, 105 (90%) had the same symptoms and 104 (89%) had the same vitreoretinal relationship bilaterally.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2000

Binding kinetics of calbindin-D(28k) determined by flash photolysis of caged Ca(2+)

We have used UV flash photolysis of DM-nitrophen in combination with model-based analysis of Oregon Green 488 BAPTA-5N fluorescence transients to study the kinetics of Ca(2+) binding to calbindin-D(28K). The experiments used saturated DM-nitrophen at a [Ca(2+)] of 1.5 microM. Under these conditions, UV laser flashes produced rapid steplike increases in [Ca(2+)] in the absence of calbindin-D(28K), and in its presence the decay of the flash-induced fluorescence was due solely to the Ca(2+) buffering by the protein. We developed a novel method for kinetic parameter derivation and used the synthetic Ca(2+) buffer EGTA to confirm its validity. We provide evidence that calbindin-D(28K) binds Ca(2+) in at least two distinct kinetic patterns, one arising from high-affinity sites that bind Ca(2+) with a k(on) comparable to that of EGTA (i.e., approximately 1 x 10(7) M(-1) s(-1)) and another with lower affinity and an approximately eightfold faster k(on). In view of the inability of conventional approaches to adequately resolve rapid Ca(2+) binding kinetics of Ca(2+) buffers, this method promises to be highly valuable for studying the Ca(2+) binding properties of other biologically important Ca(2+) binding proteins.

Acetates↗
PubMed2002

Tuning FlaSh: redesign of the dynamics, voltage range, and color of the genetically encoded optical sensor of membrane potential.

The optical voltage sensor FlaSh, made from a fusion of a GFP "reporter domain" and a voltage-gated Shaker K(+) channel "detector domain," has been mutagenically tuned in both the GFP reporter and channel detector domains. This has produced sensors with improved folding at 37 degrees C, enabling use in mammalian preparations, and yielded variants with distinct spectra, kinetics, and voltage dependence, thus expanding the types of electrical signals that can be detected. The optical readout of FlaSh has also been expanded from single wavelength fluorescence intensity changes to dual wavelength measurements based on both voltage-dependent spectral shifts and changes in FRET. Different versions of FlaSh can now be chosen to optimize the detection of either action potentials or synaptic potentials, to follow high versus low rates of activity, and to best reflect electrical activity in cell types with distinct voltages of operation.

Biosensing Techniques↗
PubMed1993

Structure-dynamics-function relationships in Asian elephant (Elephas maximus) myoglobin. An optical spectroscopy and flash photolysis study on functionally important motions.

In this work we report the thermal behavior (10-300 K) of the Soret band lineshape of deoxy and carbonmonoxy derivatives of Asian elephant (Elephas maximus) and horse myoglobins together with their carbon monoxide recombination kinetics after flash photolysis; the results are compared to analogous data relative to sperm whale myoglobin. The Soret band profile is modeled as a Voigt function that accounts for the coupling with high and low frequency vibrational modes, while inhomogeneous broadening is taken into account with suitable distributions of purely electronic transition frequencies. This analysis makes it possible to isolate the various contributions to the overall lineshape that; in turn, give information on structural and dynamic properties of the systems studied. The optical spectroscopy data point out sizable differences between elephant myoglobin on one hand and horse and sperm whale myoglobins on the other. These differences, more pronounced in deoxy derivatives, involve both the structure and dynamics of the heme pocket; in particular, elephant myoglobin appears to be characterized by larger anharmonic contributions to soft modes than the other two proteins. Flash photolysis data are analyzed as sums of kinetic processes with temperature-dependent fractional amplitudes, characterized by discrete pre-exponentials and either discrete or distributed activation enthalpies. In the whole temperature range investigated the behavior of elephant myoglobin appears to be more complex than that of horse and sperm whale myoglobins, which is in agreement with the increased anharmonic contributions to soft modes found in the former protein. Thus, to satisfactorily fit the time courses for CO recombination to elephant myoglobin five distinct processes are needed, only one of which is populated over the whole temperature range investigated. The remarkable convergence and complementarity between optical spectroscopy and flash photolysis data confirms the utility of combining these two experimental techniques in order to gain new and deeper insights into the functional relevance of protein fluctuations.

Animals↗
PubMed1995

Flash and pattern electroretinogram changes with optic atrophy and glaucoma.

We investigated recent reports that, contrary to common belief, glaucoma can affect flash as well as pattern electroretinograms. An extensive flash and pattern electroretinogram test protocol was used in a large sample of glaucoma patients and age-matched controls who were either visually normal or had other optic nerve diseases. All electroretinogram parameters were reduced and delayed in normal people > 55 years of age. The effect did not increase in later decades. In patients aged < or = 55 years, flash electroretinograms showed mild reductions and delays from optic atrophy alone. Glaucomatous ERG changes were larger and increased with disease severity. Pattern electroretinograms and oscillatory potentials were almost equally reduced in optic atrophy and all degrees of glaucoma. Mildly affected patients > 55 years of age had similar electroretinogram change to age-matched normals in most conditions. Advanced glaucoma patients showed similar differences from normal irrespective of age. This suggests that direct diagnostic application of these results to older patients will be difficult, that the ERG changes in glaucoma cannot be attributed simply to optic atrophy and that additional widespread outer retinal damage occurs in glaucoma.

Age Factors↗
PubMed1990

Treatment of post-orchiectomy hot flashes with transdermal administration of clonidine.

The occurrence of hot flashes in men after bilateral orchiectomy for prostatic carcinoma can be bothersome and difficult to treat. Transdermal clonidine was administered to 7 patients with such symptoms. In 3 patients the hot flashes were ablated and in the remaining 4 the number and frequency of attacks were considerably reduced. No significant side effects were encountered. We suggest that transdermal clonidine (0.1 mg.) administered weekly can safely control undesirable hot flashes in men after bilateral orchiectomy.

Administration, Cutaneous↗
PubMed2001

The application of magnetic resonance microimaging to the visible light curing of dental resins. Part 2. Dynamic imaging by the FLASH-MOVIE pulse sequence.

OBJECTIVES: To investigate the application of a rapid NMR imaging pulse sequence, FLASH-MOVIE, to the visible light curing of dental restorative materials. METHODS: The light guide was applied at one end of a cylindrical specimen of visible light curing unfilled resin and the light directed along the cylinder. During polymerisation an NMR imaging pulse sequence, FLASH-MOVIE, was run at 15s intervals with a 50 ms repetition time. The image of a 1mm thick vertical slice was recorded with a (125 microm)2 pixel size. RESULTS: Images with good contrast were obtained from all resin monomers. The image intensity from the polymer was indistinguishable from the background intensity. Thus, the progress of light activated polymerisation in the material could be followed in real time through a series of up to 16 images. Initially the image intensity increased in the material closest to the light guide, then decreased over time to zero. Concomitant with this fall, a "cure-front" moved through the specimen. SIGNIFICANCE: The FLASH-MOVIE NMR pulse sequence applied to microimaging of dental diacrylate resins can be used to obtain a dynamic record of visible light curing. A more refined experimental protocol will be required to apply this unique data to models proposed for this polymerisation mechanism.

Algorithms↗
PubMed1984

Flash visual evoked potential as a prognostic factor for vitreous operations in diabetic eyes.

In 116 diabetic eyes scheduled for vitreous surgery, the visual evoked potential (VEP) after flash stimulation was recorded prior to surgery. Latencies of the flash evoked potentials show a distribution suggestive of a Gaussian curve with an abnormal extension. Dividing the material into two groups based on a latency shorter or longer than 100 milliseconds revealed a highly significant difference in the visual improvement following surgery between patients with a short and patients with a long latency (P less than 0.001). With a latency longer than 100 millisec. most patients showed no visual change after operation, and among the few who did the change, consisted more often in visual reduction than improvement. Additional investigations in the study reveal that it is likely that the prolonged latency of the flash VEP is due to pathology of the retina or visual pathways.

Diabetic Retinopathy↗
PubMed1983

Presentation of a flashing light following training produces amnesia.

Long-Evans rats given exposure to a flashing-light stimulus following one-trial fear conditioning showed amnesia relative to controls not given the flashing-light experience. Together with previous results obtained in this laboratory, it is apparent that the flashing light modulates memory processing.

Animals↗
PubMed1991

Effects of flashing-diffuse light on [2-14C]deoxyglucose uptake in the visual system of the black-hooded rat.

What components of the visual system process diffuse light information? A [2-14C]deoxyglucose (2-DG) autoradiographic analysis revealed that exposure of freely moving rats (wearing light-diffusing masks) to flashing-diffuse light consistently elevated 2-DG uptake in the lateral geniculate nucleus and superior colliculus to levels rivalling those occurring in rats exposed to flashing-gratings. Uptake in visual cortex (area 17) in response to flashing-diffuse light, however, varied as a function of early contour experience, i.e. lower than that produced by darkness in rats reared with high contrast patterns, higher than darkness in rats which had been lid-sutured from the time of eye opening, and falling between these two extremes in 'ordinary' cage-reared rats. The findings point to subcortical mediation of discriminations based on diffuse light information. Cortex might participate in the processing of diffuse light information in the special case of animals lacking contour experience during development.

Animals↗
PubMed1982

Coping with the menopausal hot flash.

No data are available regarding alternatives to estrogens to help women cope with the menopausal hot flash, a condition labeled vasomotor instability of unknown etiology. This article answers questions most frequently asked by women about the hot flash, places the menopause and associated body changes within a normal growth and developmental framework, and describes methods other than estrogens that women use to cope with the hot flash.

Adaptation, Psychological↗
PubMed1998

Rapid onset pulmonary edema (flash edema) in renal artery stenosis.

Abrupt onset pulmonary edema, that rapidly resolves (flash edema) may be due to renal artery stenosis. We describe two patients with renal artery stenosis who experienced a life-threatening episode of flash edema. Relief of the stenosis prevented recurrence of the flash edema.

Aged↗
PubMed2003

The "Flash-Lag" effect occurs in audition and cross-modally.

In 1958 MacKay showed that a rigidly moving object becomes visually fragmented when part of it is continuously visible but the rest is illuminated intermittently. For example, the glowing tip of a lit cigarette moving under stroboscopic illumination appeared to move ahead of the intermittently lit body. Latterly rediscovered as "the flash-lag effect" (FLE), this illusion now is typically demonstrated on a computer monitor showing two spots of light, one translating across the screen and another briefly flashed in vertical alignment with it. Despite being physically aligned, the brief flash is seen to lag behind the moving spot. This effect has recently motivated much fruitful research, prompting a variety of potential explanations, including those based on motion extrapolation, differential latency, attention, postdiction, and temporal integration (for review, see ). With no consensus on which theory is most plausible, we have broadened the scope of enquiry to include audition and have found that the FLE is not confined to vision. Whether the auditory motion stimulus is a frequency sweep or a translating sound source, briefly presented auditory stimuli lag behind auditory movement. In addition, when we used spatial motion, we found that the FLE can occur cross-modally. Together, these findings challenge several FLE theories and point to a discrepancy between internal brain timing and external stimulus timing.

Auditory Perception↗
PubMed2002

Neural delays, visual motion and the flash-lag effect.

In the primate visual system, there is a significant delay in the arrival of photoreceptor signals in visual cortical areas. Since Helmholtz, scientists have pondered over the implications of these delays for human perception. Do visual delays cause the ' position of a moving object to lag its 'real' position? This question has recently been re-evaluated in the context of the flash-lag phenomenon, in which a flashed object appears to lag behind a moving object, when physically the two objects are co-localized at the instant of the flash. This article critically examines recent accounts of this phenomenon, assesses its biological significance, and offers new hypotheses.

Journal Article↗
PubMed1982

Flash electroretinogram abnormalities in patients with clinically definite multiple sclerosis.

We studied the flash electroretinograms (ERGs) of 105 patients with multiple sclerosis who were divided into four groups. The first group had no history or clinical evidence of optic nerve dysfunction, the second and third groups had either left or right optic nerve disease respectively, and the fourth group had historical or clinical evidence of bilateral optic nerve disease. Statistical analysis of the data using analysis of variance (ANOVA) showed that the group of patients with no history or clinical evidence of optic nerve disease had no significant difference from the control group for their peak b-wave implicit times but the other three groups were significantly delayed on the affected side(s). Using the Mann-Whitney U-test we found all four patient groups had significantly greater absolute interocular latency differences from the control group. The electroretinal contribution to flash VEP delay was also investigated. In those patients with unilateral or bilateral optic nerve disease we found that in 14-31% of those patients with flash VEP delay there was also abnormal prolongation of the ERG b-wave. These results confirm a high incidence of retinal dysfunction in multiple sclerosis patients and may suggest that transynaptic degeneration of retinal structures occurs in optic nerve demyelination. The significant absolute interocular latency difference in particular may provide another electrophysiological parameter to establish a diagnosis of multiple sclerosis in suspect cases.

Diagnosis, Differential↗
PubMed1993

Structure-function relations in photosystem II. Effects of temperature and chaotropic agents on the period four oscillation of flash-induced oxygen evolution.

The characteristic period four oscillation patterns of oxygen evolution induced by a train of single-turnover flashes were measured in dark-adapted samples as a function of temperature and upon addition of chaotropic agents. The following results were obtained: (a) Within the range of 0 < theta < 35 degrees C, the ratio of the oxygen yield induced by the 4th and 3rd flashes of the train, Y4/Y3, and the oxygen yield induced by the 2nd flash, Y2, exhibit similar dependencies on the temperature in isolated thylakoids, PS II membrane fragments, and inside-out vesicles. (b) Below a characteristic temperature theta c of 20-25 degrees C, the values of Y4/Y3 and Y2, which reflect (at constant S0 dark population) the probabilities of misses and double hits, respectively, remain virtually independent of temperature, whereas above theta c these parameters increase. (c) The dark decays of S2 and S3 via fast and slow kinetics due to reduction of the water oxidase by YD and other endogenous electron donor(s), respectively, exhibit comparatively strong temperature dependencies in thylakoids with the following activation energies: EA(S2fast) = 55 kJ/mol, EA(S3fast) = 50 kJ/mol, EA(S2slow) = 85 kJ/mol, and EA(S3slow) = 75 kJ/mol. The activation energy of S0 oxidation to S1 by YDox was found to be markedly smaller with a value of EA(S0) = 30 kJ/mol. (d) Incubation with chaotropic agents at concentrations which do not significantly impair the oxygen evolution capacity leads to modifications of the oscillation pattern with remarkable differences for various types of agents: Tris and urea are practically without effect; guanidine hydrochloride affects Y4/Y3 in a similar way as elevated temperature but without significant changes of Y2 and the decay kinetics of S2 and S3; and anions of the Hofmeister series (SCN-, ClO4-, I-) cause a drastic destabilization of YDox. Possible structure-function relations of the PS II complex are discussed on the basis of these findings.

Guanidine↗