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PubMed2000

Beneficial effect of combination therapy with ozagrel and pranlukast in exercise-induced asthma demonstrated by krypton-81 m ventilation scintigraphy--a case report.

INTRODUCTION: We evaluated the effect of combination therapy with thromboxane A2 synthesis inhibitor and leukotriene receptor antagonist in a patient with exercise-induced asthma using krypton-81 m ventilation scintigraphy. CLINICAL PICTURE: In a patient with exercise-induced asthma, we found exercise-induced abnormalities of respiratory function test and ventilation scintigraphy, and increases in plasma concentrations of thromboxane B2 and leukotriene C4 with exercise. TREATMENT: A thromboxane A2 synthesis inhibitor (ozagrel) and a leukotriene receptor antagonist (pranlukast) were prescribed. OUTCOME: After treatment for 2 weeks, abnormalities of respiratory function test and ventilation scintigraphy improved. CONCLUSIONS: The combination therapy with ozagrel and pranlukast might be useful for the relief of symptoms in patients with exercise-induced asthma, and krypton-81 m ventilation scintigraphy could be a useful tool for visible evaluation of treatment.

Asthma, Exercise-Induced↗
PubMed1977

Response of cultured mammalian cells to accelerated krypton particles.

One of the more interesting observations made in early studies with heavy ions is that the cross-section of the radiosensitive area in mammalian cells increases with LET of HZE particles. It is not certain, however, whether this radiosensitive area is limited to the nuclear area of cells. The successful acceleration of krypton ions to 8.5 MeV/amu at the HILAC Lawrence Berkeley Laboratory, has provided an opportunity to gain more information on this question. Cultured human kidney cells (T-1), growing in exponential phase, were exposed to 3 MeV/amu krypton particles and their colony-forming ability studied. The survival curve was found to be exponential with a mean lethal dose D0=720 rad. A calculation of the cross-section of the radio-sensitive area from the data obtained gives a value of about 145 micrometers2. Present results suggest that the inactivation cross-section stays about the same for heavy ions that have LET greater than 20,000 MeV cm2 g-1, that the nucleus is the only sensitive site for high LET radiation and that a single hit of a heavy ion with very high LET in the nuclear region of the cell can lead to lethal effects. Such particles are therefore extremely dangerous to proliferating living cells.

Cell Line↗
PubMed2005

[Gene expression patterns of choroidal neovascularization induced by krypton laser photocoagulation].

OBJECTIVE: To explore the gene expression patterns of choroidal neovascularization with gene chip technology. METHODS: Total RNA was isolated from normal choroid and choroid tissues with neovascularization induced by krypton laser photocoagulation in Brown Norway rat. The mRNA was purified and was reversely transcribed to cDNA to prepare for hybridization probes. In choroidal neovascularization, the differentially expressed genes were assayed with gene chips which contained 5705 rat genes. RESULTS: There were 46 genes expressed differentially in choroidal neovascularization. Of these, the expression of 3 genes was upregulated and 43 genes downregulated. These genes were involved in the function of transport, signal, metabolism, development and differentiation of cell adhesion. CONCLUSION: Numerous genes are involved in the development of choroidal neovascularization induced by krypton laser photocoagulation.

Animals↗
PubMed1990

Static and kinetic perimetry results of krypton red laser treatment for macular edema complicating branch vein occlusion.

Twenty patients with clinical and angiographic evidence of recent branch vein occlusion complicated by macular edema were assigned to receive krypton red laser treatment if their macular edema lasted more than three months. Visual acuity, static and kinetic perimetry, fundus photography, and fluorescein angiography were evaluated before treatment and at two-month intervals thereafter. Visual acuity improved by two lines one year after treatment in 65% of patients. Each of these patients had a complete perifoveal capillary arcade. Static perimetry results correlated well with visual acuity, and a significant threshold improvement was detected in these patients. Visual-acuity results and static and kinetic perimetry findings are presented. The rationale for selection of the krypton red wavelength (647 nm) is discussed.

Aged↗
PubMed1988

Argon green and krypton red laser treatment of diabetic macular edema.

We treated 69 eyes of 44 patients who had clinically significant macular edema with argon or krypton laser photocoagulation or both. The mean initial visual acuity was 20/40. Patients were followed for 6 to 63 (mean 19.7 +/- 11.0) months. There was a mean loss of three letters in acuity, but the difference between initial and final acuity was not statistically significant. In 43 eyes the acuity remained within two lines of the initial acuity, in 17 there was a loss of two lines or more, and in 9 the acuity improved by two lines or more. The initial acuity correlated highly to the final acuity (p less than 0.0001). Multiple linear regression showed that pretreatment existence of macular ischemia or diffuse macular edema or both, when adjusted for initial acuity, age, insulin dependence and duration of diabetes mellitus, was predictive of poorer final acuity than in patients without ischemia or diffuse edema. The results support a consensus that macular edema should be treated early. In view of the conflicting experimental and clinical studies of grid techniques of photocoagulation and the role of the krypton laser, further clinical studies of the treatment of diabetic macular edema are warranted.

Adult↗
PubMed1986

Regional comparison of technetium-99m DTPA aerosol and radioactive gas ventilation (xenon and krypton) studies in patients with suspected pulmonary embolism.

The regional distribution of [99mTc]DTPA aerosol was compared with that of 133Xe (n = 30) and krypton (n = 24) in a group of patients with suspected pulmonary embolism. All patients had an aerosol study using a recently available commercial generator system, a ventilation study with one of the gases, and perfusion imaging. Regional information was assessed visually on xenon, krypton, and aerosol studies independently by considering each lung as three equal-sized zones. In addition, gas ventilation findings peripheral to regions of aerosol turbulence ("hot spots") were evaluated. Only 64% of the zones were in complete agreement on xenon and aerosol. Most of the discordance between xenon and aerosol was accounted for by minor degrees of 133Xe washout retention in zones that appeared normal in the aerosol study. An agreement rate of 85% was noted between 81mKr and aerosol regionally. The regions of discordance between aerosol and gas studies, however, usually were associated with unimpressive perfusion defects that did not change the scintigraphic probability for pulmonary embolism in any patient. Regarding zones of aerosol hyperdeposition, 76% had associated washout abnormalities on xenon; however, there was no correlation between the presence of these abnormalities or perfusion abnormalities. The results confirm the high sensitivity of 133Xe washout imaging, but suggest that radioaerosol imaging will detect most parenchymal abnormalities associated with perfusion defects of significance.

Adult↗
PubMed1986

Gated right ventricular studies using krypton-81m: comparison with first-pass studies using gold-195m.

Krypton-81m, given by continuous i.v. infusion, has been successfully used for the equilibrium ECG-gated assessment of right ventricular function. We compared gated studies with 81mKr (half-life 13 sec) with first-pass studies using 195mAu (half-life 30.5 sec). Krypton studies analyzed using variable regions of interest (ROIs) led to a significantly higher calculated right ventricular ejection fraction (RVEF) than with a fixed ROI, both with and without background correction. The differences between first-pass studies and gated studies without background correction were significant (p less than 0.01), whereas they were not with background correction. These data suggest that large systematic errors exist in the calculation of RVEF depending on the analysis method and that background correction is important when different techniques are compared.

Adult↗
PubMed1986

Ultrastructure of Bruch's membrane after krypton laser photocoagulation. I. Breakdown of Bruch's membrane.

Previous observations on rats suggested that subretinal neovascularization does not require a prior break in Bruch's membrane (BM). We verified this observation by using scanning electron microscopy to examine large expanses of BM that became exposed following ophthalmoscopically white krypton laser burns. Bruch's membrane appeared intact in the acute phase after injury. Subsequently, slitlike defects in BM were associated with penetrating choroidal capillaries. These observations were consistent with transmission electron microscopic findings of cellular protrusions arising from the choriocapillary endothelial cells and from regenerating retinal pigment epithelial (RPE) cells invading BM. These cell-formed defects in BM differed from thermal defects in appearance, size, and onset of occurrence. Endothelial cells penetrated all layers of BM, including the RPE basement membrane. We conclude that endothelial cells can erode their own basement membrane and the RPE basement membrane, and krypton laser burns with or without immediate rupture of BM induce cellular activity that may result in defects in BM.

Animals↗
PubMed1988

Subretinal neovascularization in a pseudophakic eye treated with krypton laser photocoagulation. A clinicopathologic case report.

A 76-year-old myopic woman who had undergone bilateral extracapsular cataract extractions and received posterior intraocular lens implants underwent two sessions of krypton laser photocoagulation for subretinal neovascularization secondary to age-related macular degeneration in her right eye. The patient expired and histopathologic examination of her treated eye showed a posterior chamber intraocular lens with both haptics in the ciliary sulcus, areas of macular degeneration, evidence of krypton laser photocoagulation including a full-thickness retinal scar, and an area of clinically unsuspected subretinal neovascularization.

Aged↗
PubMed1989

Persistent and recurrent neovascularization after krypton laser photocoagulation for neovascular lesions of ocular histoplasmosis. Macular Photocoagulation Study Group.

Persistence and recurrence of choroidal neovascularization after initial treatment with laser photocoagulation have been shown to be major contributors to loss of visual acuity. The 144 eyes assigned to krypton red laser photocoagulation in the Ocular Histoplasmosis Study-Krypton Laser were examined to describe persistence and recurrence in these patients. Persistent neovascularization was observed among 23% of treated patients and recurrent neovascularization was observed among an additional 8%. Both persistence and recurrence were accompanied by an increased frequency of severe visual loss. Patients with high blood pressure were more than 2.5 times as likely to have persistent neovascularization as patients without high blood pressure (95% confidence interval = 1.5, 4.8). Eyes in which the neovascular component of the complex was within 200 microns of the center of the foveal avascular zone were twice as likely to have persistent neovascularization (95% confidence interval = 1.2, 4.6). Eyes in which the treatment did not cover the neovascularization completely or did not meet the required level of intensity on the foveal side had a persistence rate approximately three times that of eyes in which the neovascularization was covered completely by intense, confluent burns (95% confidence interval = 1.7, 6.5). This last finding is of particular importance for ophthalmologists who treat similar patients.

Adult↗
PubMed1990

Krypton laser photocoagulation for neovascular lesions of age-related macular degeneration. Results of a randomized clinical trial. Macular Photocoagulation Study Group.

The Age-Related Macular Degeneration Study-Krypton Laser (AMDS-K) is a multicenter controlled clinical trial designed to determine whether krypton red laser photocoagulation is of value in preventing visual acuity loss in eyes with macular degeneration that have either choroidal neovascularization 1 to 199 microns from the center of the foveal avascular zone or choroidal neovascularization 200 microns or farther from the foveal avascular zone center with blood and/or blocked fluorescence extending within 200 microns of the foveal avascular zone center. Recruitment ended in December 1987 after 247 patients had been assigned to photocoagulation and 249 patients had been assigned to no treatment. At 3 years after randomization, 49% (86/174) of treated eyes, in contrast to 58% (98/169) of untreated eyes, had lost six or more lines of visual acuity. The average visual acuity of treated and untreated eyes at that time was 20/200 and 20/250, respectively. The benefit of laser treatment was largest among patients without evidence of hypertension and diminished to no apparent benefit among patients who had highly elevated blood pressure and/or used antihypertensive medication. Treatment of lesions meeting the AMDS-K eligibility criteria in eyes of patients with no hypertension is recommended. However, treatment cannot be recommended uniformly for patients with definite hypertension having lesions similar to those of patients enrolled in the AMDS-K.

Age Factors↗
PubMed1990

Persistent and recurrent neovascularization after krypton laser photocoagulation for neovascular lesions of age-related macular degeneration. Macular Photocoagulation Study Group.

The persistence and recurrence of choroidal neovascularization after initial treatment with laser photocoagulation have been shown to be major contributors to loss of visual acuity. The 247 eyes assigned to krypton red laser photocoagulation in the Age-Related Macular Degeneration Study-Krypton Laser were examined to describe the incidence, timing, visual impact, and potential risk factors for persistence and recurrence. Persistent neovascularization detected within 6 weeks of initial treatment was observed in 32% of treated eyes, and recurrent neovascularization was estimated by life-table methods to develop in an additional 47% over a 5-year period. Both persistence and recurrence were accompanied by an increased frequency of severe visual loss. The persistence rate among eyes having 10% or more of the foveal side of the neovascular membrane not covered by treatment was twice as high as in eyes having more extensive coverage. Patients having a fellow eye with a neovascular membrane or scar, a fellow eye with 20 or more drusen in the central macula, or a fellow eye with nongeographic atrophy at initial visit had more recurrences than patients without these characteristics. Ophthalmologists treating similar lesions may be able to reduce persistent neovascularization and the associated visual loss by covering the entire lesion with treatment.

Age Factors↗
PubMed1983

Krypton laser treatment in disciform macular lesions.

Krypton laser treatment was performed in 30 eyes with subretinal neovascularization, in 27 eyes associated with senile exudative maculopathy. In 22 eyes treatment was initially successful but late recurrences occurred in 5 eyes; in only one of them was additional krypton treatment again successful. In 8 eyes the response to treatment was insufficient. The outcome in our series is promising but long-term results may be less favourable on account of more recurrences and progression of the underlying maculopathy.

Adult↗
PubMed1981

Treatment of macular subretinal neovascularization with the red-light krypton laser in presumed ocular histoplasmosis syndrome.

A patient with presumed ocular histoplasmosis and decreased visual acuity in one eye had subretinal neovascularization and retinal hemorrhage in the macular area. Argon-laser treatment to eradicate the subretinal neovascular membrane was contraindicated because of the proximity of the hemorrhagic lesion to the fovea. We used a red-light krypton laser (647 nm) because the light is not absorbed by the hemoglobin in the retinal hemorrhage or by the macular luteal pigment (xanthophyll), and because it is transmitted into the choroid, allowing treatment within the macular zone with less damage to the internal retinal elements. After treatment, the subretinal neovascular membrane completely disappeared and the macular hemorrhage cleared. To the best of our knowledge, this is the first time that a histoplasmic macular subretinal neovascular membrane has been treated with the red-light krypton laser.

Eye Diseases↗
PubMed1982

A comparative study of argon and krypton laser. Photocoagulation in the treatment of presumed ocular histoplasmosis syndrome.

Ninety eyes from 88 patients with active macular subretinal neovascular membranes of presumed ocular histoplasmosis were treated with photocoagulation: 45 eyes with blue-green argon laser and 45 with red krypton laser. Final visual results are compared between these two series and natural course of the disease. The krypton laser photocoagulated eyes obtained better final visual results when compared with both the argon laser treated series and natural course.

Adult↗
PubMed1982

Krypton red laser photocoagulation for subretinal neovascularization.

A series of 75 well-defined, consecutive patients with subretinal neovascularization secondary to a variety of macular diseases were treated with krypton red laser (KRL) photocoagulation and are reported on prospectively. Two thirds of the patients had subretinal neovascularization secondary to involutional (senile) macular degeneration. Most patients had clinical and/or fluorescein angiographic manifestations of neovascularization that posed a poor visual prognosis. The technique of treatment using the krypton red wavelength, as well as special considerations in the pre- and post-operative management, are reviewed. The results suggest that this wavelength is effective in the successful, anatomic elimination of subretinal neovascularization and improvement of the visual status with certain potential advantages compared to conventional argon blue-green laser (ABGL) radiation. Since this clinical study is void of randomization and controls, no absolute conclusions can be made with regard to the effectiveness of this form of treatment compared to other laser treatments or to the natural course of the macular diseases themselves. However, the results of this study are extremely encouraging, warranting further investigation.

Fluorescein Angiography↗
PubMed1982

Treatment of neovascular senile maculopathy at the foveal capillary free zone with red krypton laser.

Sixty-eight eyes with neovascular senile maculopathy involving the capillary free zone that were assigned randomly for red krypton laser photocoagulation were followed for two years and compared to 55 eyes with the same disease that were not treated. In the majority of the studied eyes there was a decline of visual acuity during the follow-up period. However, an increase in visual acuity was encountered in one third of treated eyes, but no increase in the untreated eyes. The extent of visual acuity deterioration was greater in the nontreated than in the treated eyes. Eyes that were treated when visual acuity was between 6/9-6/60 generally belonged to a better final visual acuity group than those eyes that were treated when visual acuity was less than 6/60. The technique of red krypton laser photocoagulation is described, the rationale for this treatment is discussed, and the results of the treatment are evaluated.

Aged↗
PubMed2006

Laser bleb reduction for bleb dissection with krypton green laser: technique and outcomes.

PURPOSE: Lasers have been used to treat dysfunctional blebs, but the laser remodeling of blebs that dissect into the palpebral fissure has not been reported. We describe the unique use of krypton green laser to treat dissected blebs and discuss treatment outcomes. PATIENTS AND METHODS: Retrospective review of consecutive patients undergoing laser bleb reductions (LBRs) over a 6-year period. Failure was defined as persistent dissection and/or symptoms or loss of intraocular pressure (IOP) control despite medications. RESULTS: Sixteen patients underwent a total of 23 LBRs and were followed-up for a mean of 12.4 months (median = 9.5 mo). Ten patients (63%) were treated successfully, and 6 patients (37%) failed treatment. Persistent dissection and/or symptoms were the most common reasons for failure (5/6), whereas 1 patient lost IOP control. Three (30%) of those treated successfully required the reintroduction of ocular hypotensive medications for pressure control. The mean IOP increased from 9.1 +/- 5.2 mm Hg before treatment to 11.7 +/- 8.1 mm Hg after treatment (P = 0.02). Common complications included intraoperative discomfort (26%), conjunctival injection (22%), postoperative discomfort (13%), and dissection into the untreated side (9%). In the failure group, more laser spots (P = 0.05) and higher power levels (P = 0.00001) were used. CONCLUSIONS: Krypton LBR may be a useful initial treatment modality for symptomatic bleb dissection. Success rates may be modest, but most adverse effects are mild and/or transient; however, significant loss of IOP control can occasionally occur.

Aged↗