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PubMed2005

[Flash full-field electroretinography in diseases with night blindness].

PURPOSE: The aim of this study is to present similarities and differences of electroretinograms in early stages of retinal diseases with nyctalopia. MATERIAL AND METHODS: Flash full-field electroretinography was done according to ISCEV standards and also with chromatic stimulations in patients with nyctalopia, who were diagnosed as various forms of congenital stationary night blindness and various types of retinitis pigmentosa, choroideremia, gyrate atrophy and also in patients with nyctalopia, because of unknown reason. ERG results were compared with normal values and with each other. RESULTS: In diseases with nyctalopia the function of peripheral retina is markedly abnormal and scotopic ERG is significantly reduced or even absent. In retinitis pigmentosa a-wave is small or absent especially scotopic but photopic ERG is also abnormal. Well preserved a-wave distinguished ERG of patients with stationary night blindness from the other progressive diseases of retina or choroid. CONCLUSIONS: In patients with nyctalopia using ERG is possible to obtain which retinal elements do not work but it is only start point to following diagnostic examinations, to make proper final diagnosis.

Adolescent↗
PubMed2005

[The study of the effect of the administration of mannitol on flash visual evoked potentials].

OBJECTIVE: To study the relationship between the change of N2 wave in flash visual evoked potentials (fVEP) and the intracranial pressure after the administration of mannitol. METHODS: Fifty-two patients with elevated intracranial pressure were chosen and are divided into two groups: the former (n = 32) were treated with mannitol, the latter (n = 20) were treated with mannitol and glycerol and sodium chloride injection. The latency and amplitude of N2 wave of fVEP was measured by NIP-200 noninvasive intracranial pressure apparatus before and after the 1st, 4th, 10th administration of mannitol. RESULTS: The latency of N2 wave began to reduce at 30 min after the injection of mannitol and was lowest at 2 h. At 4 h after the injection of mannitol, the latency of N2 wave increased but was still shorter than that before the injection of mannitol. The amplitude of N2 wave did not change significantly. The reduction of the latency of N2 wave after the administration of mannitol decreased with the multiple mannitol injection. The latency of N2 wave did not change significantly after the administration of mannitol when combined with glycerol and sodium chloride injection. CONCLUSION: The latency of N2 wave of fVEP changes after the administration of mannitol, which suggests that the change of the latency of N2 wave of fVEP can reflect the change of intracranial pressure.

Adult↗
PubMed2006

[The influence of dopamine injected into the lateral geniculate body on flash visual evoked response in rats].

PURPOSE: Numerous neurotransmitters and neuromodulators operating on all levels of the visual system, influence the parameters of cortical evoked response. The aim of this study was to find the influence of dopamine (DA) injected into the lateral geniculate body (nucleus) on flash visual evoked response (FVEP). MATERIAL AND METHODS: The experiments were performed on adult Wistar rats. They were implanted with 1 caniula conducted into the lateral geniculate body and 2 electrodes: active under the skull on dura mater in occipital region of brain and reference one on the skull in the interorbital region. FVEPs curve before and after injection into the lateral geniculate body 0.9% NaCl and DA were analyzed. RESULTS: DA in the lateral geniculate body causes increasing latency and amplitude of FVEP peaks. CONCLUSIONS: Dopamine in the lateral geniculate body can improve visual perception in the occipital cortex.

Animals↗
PubMed2006

[The influence of stimulation dopaminergic D, i D2 receptors in lateral geniculate body on flash visual evoked potentials (FVEP) in rats].

PURPOSE: The topic of this paper is to define the influence of stimulation dopaminergic D1 i D2 receptors in lateral geniculate body by flash visual evoked potentials (FVEP). MATERIAL AND METHODS: Wistar rats were examined. There were stereotaxically implanted with guide caniula into the lateral geniculate body to inject substances and with VEPs electrodes on the skull and on the surface of visual cortex. VEPs curve before and after injection into the lateral geniculate body: 0.9% NaCl, agonists of dopamine receptors D1 - SKF 38393, and D2 Quinpirole and also the same agonist after antagonists D1 - SCH 23390, i D2 Sulpiride were analyzed. RESULTS: Stimulating receptors D1 in the lateral geniculate body cause amplitude increase and shortness of latency. Quinpirole, agonist of D2 receptor do not significant change FVEPs curve. CONCLUSIONS: Stimulation of D1 receptors in the lateral geniculate body can improve visual transmission throught it and response in the occipital cortex.

Animals↗
PubMed1991

[Flash-evoked visual potentials in the early diagnosis of optic nerve injury due to craniofacial fractures].

Impairment or loss of vision due to optic nerve injury occurs in about 10% of patients with cranio-facial fractures. The assessment of optic nerve function is important for decisions regarding optic nerve decompression. But examination of vision and pupillary reflexes may be difficult, especially in uncooperative patients with reduced consciousness and primary disturbances of pupillary functions. In these cases, optic nerve function can be monitored by means of flash-evoked visual potentials elicited by use of a LED-goggle stimulator. VEPs were recorded in ten patients with head injuries comprising cranio-facial fractures and cerebral concussion with prolonged alteration of consciousness. Recordings were obtained in the acute phase upon admission. Visual acuity and visual fields were examined after regaining consciousness and the clinical findings correlated to the initial VEPs. Upon clinical examinations, four patients with initially normal VEPs had normal vision on both eyes. One patient initially revealed unilateral reduction of the VEP-amplitude of more than 50% and clinically showed a concentric visual field defect. Three patients with unilateral loss of potentials were amaurotic on this side. Perception of light was preserved in one patient in whom VEPs were absent. One patient with bilateral loss of potentials was blind when consciousness was regained. In general, pupillary light reflexes tested at admission corresponded to the VEP-findings. In two cases, however, pupillary reactivity was lost, but VEPs were still present. These patients had normal vision, but exhibited a lesion of the efferent pathways of pupillary reflexes. In two other patients, examination of pupillary reactivity could not be performed due to extreme edema of the eyelids.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Flash lamp pumped dye laser for rosacea-associated telangiectasia and erythema.

The persistence of facial telangiectasis and erythema in patients with rosacea frequently presents a major cosmetic problem. It may also contribute to relapses of papular and pustular lesions. This study of 27 patients treated for their telangiectasia and erythema with a flash lamp pumped dye laser tuned at 585 nm is described. The laser gave good or excellent reduction of telangiectasia and erythema and overall appearance in 24 of the patients with between one and three treatments. In addition, papule and pustule activity was decreased in 59.2% of the patients, with those with the most severe pre-treatment activity having the most significant improvement. It is suggested that this is a useful additional form of treatment that may improve the telangiectasia and erythematous component of rosacea.

Adult↗
PubMed1977

Direct generation of superoxide anions by flash photolysis of human oxyhemoglobin.

The results presented in this report suggest that human oxyhemoglobin can directly form methemoglobin and superoxide anion when flashed with low intensity (38 joules) white light. The effect only occurred in quartz but not glass (cut off lambda approximately equal to 300 nm) cuvettes. The formation of O2 was established by observing the reduction of oxidized cytochrome c concomitant with MetHb formation at pH 9, and by showing that superoxide dismultase and catalse inhibit cytochrome c reduction at that pH. The inhibition of cytochrome c reduction by catalase led us to explore the possibility that H2O2 might reduce oxidized cytochrome c at pH 9. We show that H2O2 does reduce oxidized cytochrome c at that pH but not at pH 7. Furthermore, catalase but not superoxide dismutase, almost completely inhibited this reduction process. These experiments serve to confirm our interpretation of the effect of catalase on the reduction of oxidized cytochrome c in the photolytic experiments, thus establishing that H2O2 was also formed. In addition, we were able to identify the production of O2 and H2O2 due to the photolysis of water in agreement with the results of McCord and Fridovich ((1973) Photochem. Photobiol. 17, 115-121). Production of O2 from this source was considerably less than that observed when HbO2 was present. Addition of MetHb to aerated solutions of oxidized cytochrome c did not cause additional reduction, unlike addition of HbO2. The production of MetHb was found to have at least two components. One component was the primary photolytic process, and the second was a strongly pH-dependent reattack of HbO2 by O2. Addition of superoxide dismutase inhibited this second component, but did not significantly effect the primary photolytic process.

Cytochrome c Group↗
PubMed1991

[MRT of orofacial tumors--initial clinical experiences with turbo-flash intensity studies].

We examined 36 patients with carcinomas of the tongue and the floor of the mouth. In 11 cases, a clear definition of the tumor extent was not possible using T2 w. spin echo sequences and T1 w. spin echo and gradient echo sequences after injection of contrast material. This delineation was attained with Turbo-FLASH intensity-vs-time studies (Gad-DTPA). The time of acquisition of each measurement was about 1 sec. At the end of injection of Gad-DTPA, 30 measurements with a delay of 1 sec between two measurements were performed. Using this technique, a marginal zone at the boundary of the tumor of very high signal intensity was visible within first minute after Gadolinium injection. This method is not required in the case of clearly hypointense (majority of the tumors) or hyperintense (minority) lesions on T1 w. Gadolinium-enhanced SE or GE images.

Aged↗
PubMed1990

[Dynamic MRI of liver tumors--evaluation by inversion recovery snap shot FLASH MR imaging].

We have studied 20 patients with liver tumor (hepatoma 12, hemangioma 6, metastatic tumor 2) using inversion recovery snap shot FLASH dynamic MR imaging. After intravenous injection of Gd-DTPA, serial 17 images were obtained during 7 minutes. Hepatoma showed central enhancement on early phase (0-20 sec) in 11 patients and absent or less enhancement than surrounding liver parenchyma on late phase (1-3 min) in 12 patients. Hemangioma showed peripheral enhancement on early phase in 6 patients, and slight to moderate enhancement on late phase in 5 patients. Peripheral slight enhancement were seen on late and delayed (5-7 min) phase in two patients with metastatic liver tumor. These characteristic enhancement patterns should facilitate differential diagnosis of liver tumors.

Aged↗
PubMed1991

Capillary hemangiomas and treatment with the flash lamp-pumped pulsed dye laser.

Strawberry, or capillary, hemangiomas are common vascular neoplasms, with an incidence of approximately 2.6% in neonates. They usually develop in the first few weeks of life, so that between 1 month and 1 year the incidence rises to between 8.7% and 10.1%. These lesions may grow quite large in the first year of life, and they may ulcerate or obstruct a vital organ or function. The great majority will spontaneously regress after the first year of life. Parents are often alarmed at the sight of these hemangiomas and need reassurance that the great majority will regress spontaneously. Treatments such as cryosurgery, irradiation, radium instillation, corticosteroid therapy, or surgical excision are often ineffective or cause significant morbidity. We describe 10 children with capillary hemangiomas treated with the flash lamp-pumped pulsed dye laser. The patients ranged in age from 7 weeks to 5.5 years at the beginning of laser therapy. The patients underwent 3.1 +/- 1 (mean +/- SD) laser treatments, with a mean regression of the lesions of 69.9% +/- 4.5%. All patients demonstrated some diminution in the size and color of their hemangiomas after the treatments, and there were no ill effects, such as ulceration, hemorrhage, infection, or scarring. There was no evidence of hyperpigmentation or hypopigmentation. Pulsed dye laser therapy should be considered as an option in the treatment of capillary hemangiomas, preferably prior to their full evolution. It is also a useful therapeutic approach in those hemangiomas that are slow to regress in older children.

Child, Preschool↗
PubMedDate not supplied

Disinfection and flash sterilization in the operating room.

Items that enter sterile tissue or the vascular system are considered critical items and must be sterile. Semicritical items are those objects that come in contact with mucous membranes or with skin that is not intact; they require high-level disinfection. Noncritical items come in contact with intact skin and require low-level disinfection. Flash sterilization is overused in hospitals. Control measures should be used to minimize infections traced to sterilizer failure.

Disinfectants↗
PubMedDate not supplied

[Light-dependent reactions of Mn2+ and P700+ in chloroplasts during flash illumination].

The changes of the light-induced ESR signal I and exogeneous Mn2+ ions in chloroplasts of Vicia faba plants have been studied under short flash excitation and weak background far red illumination. It is shown that Mn2+ ions reactivate the noncyclic electron transport in chloroplast previously inactivated with high tris concentrations under pulse illumination. Simultaneously with P700+ reduction the ESR signal of free Mn2+ ions decays stoichometrically to P700+ reduction.

Binding Sites↗
PubMed1990

[Visual evoked potentials produced by monocular flash stimuli in the cerebral cortex of the rabbit. I. Typology].

Visually evoked potentials obtained from the cerebral cortex of pigmented rabbits in response to monocularly applied flashes were studied. In agreement with their morphology, the VEP of the cerebral cortex of the rabbit were classified in three fundamental types: the first one is characterized by the presence of a large positive wave, (P1), followed by a negative wave, (N1), and finally, another positive wave, (P2); these last two being of quite variable amplitudes. The second one is characterized by an initial large negative wave, (N1), followed by a usually large positive wave, (P2). Should a positive, (P1), appear previous to N1 there would be little amplitude. The third one is characterized by the presentation of an early negative wave, (N0), of variable amplitude. This is usually followed by a large wave, (P1). N1 and P2 are present but their amplitude is variable.

Animals↗
PubMed1990

[Visual evoked potentials to a light flash in patients with optic nerve atrophy].

Informativeness of different methods used for registration of optic generated potentials in response to light flash (FOP) has been studied in 27 healthy persons and 21 patients (32 eyes) with partial atrophy of the optic nerve. It is shown that the most informative one for diagnosing optic nerve atrophy and determining visual acuity in such patients is a method of investigation of the critical incidence of rythm reproduction of FOP light flickerings. Considering the complexity and difficulty of the mentioned method for its practical usage, a simplified method is proposed; a registration of FOP of a stable state with the incidence of stimulations of 33 Hz, that allows to detect cases of pathology with visual acuity not less than 0.2.

Evoked Potentials, Visual↗
PubMed1990

Quantitative evaluation of hyaline cartilage disorders using flash sequence. I. Method and animal experiments.

A method for quantitative evaluation of hyaline cartilage signal intensities has been developed in an experimental study of 6 swine knees with different types of arthritis. A FLASH sequence with TR 50 ms, TE 10 ms and flip angles of 5, 10, 20, 25, 30, 35, 50 and 90 degrees was employed. Two parameters of the signal intensity flip angle curves proved to be useful for tissue characterisation: The initial increase (A) and the maximum (M).

Animals↗
PubMed1990

Flash electroretinograms and pattern visually evoked cortical potentials in Behçet's disease.

Behçet's disease with posterior uveitis was studied in 12 cases by flash electroretinography (FERG) and pattern visually evoked cortical potential (PVECP). Disappearance of oscillatory potentials was the initial change noted in FERG. Subnormal FERG and a delay in peak latency of the P100 component of PVECP were observed in patients with poor visual acuity and long-standing Behçet's disease. Amplitudes of PVECP were significantly decreased in these patients. It was suggested that FERG together with PVECP were good indicators for monitoring posterior segment changes and visual prognosis in Behçet's disease.

Adult↗
PubMed1990

[Diagnosis of oropharyngeal function with FLASH-MR tomography].

Magnetic resonance imaging (MRI) has several advantages over conventional X-ray methods: the patient is not exposed to radiation; images of any chosen level can be taken without changing the position of the patient; soft tissues are well differentiated; and artefacts due to dental materials are avoided. Thus, in certain fields of ENT diagnosis MRI is superior to computed tomography, for example, in the imaging of acoustic neuromas, glomus tumours and tumours of the parotids, oropharynx and orbit. The measuring time per slice image, which was previously measured in minutes, has been reduced by a factor up to 1000 by the FLASH (fast low angle shot) technique. Thus, it is now possible to follow human physiological processes on an MRI film with a frame speed of 5 pictures using a whole-body magnet. Films of speech, tongue movements and the act of swallowing reveal the value of this technique for the functional diagnosis of disease of the oropharynx. Precise imaging of the anatomical and functional situation, especially of soft tissues, is superior to that of previous methods such as ultrasound, X-ray, and endoscopy.

Deglutition↗