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PubMedDate not supplied

Choroidal osteoma. Treatment of associated subretinal neovascular membranes.

Treatment of subretinal neovascular membranes associated with choroidal osteomas is described. Early recognition of the membranes, aided by Amsler grid self-assessment, allowed initiation of photocoagulation treatment while the lesions were still extrafoveal. In one patient, initial treatment was performed with the argon green laser and subsequent treatments were applied with the krypton red laser. In two other patients, argon-laser photocoagulation alone was used to destroy subretinal neovascular membranes. Post-treatment evaluations in one patient demonstrated persistence of recurrence of neovascular tissue and allowed for prompt retreatment. Follow-up evaluations have shown that treatment resulted in persistent destruction of the subretinal neovascular membrane in two patients, with stabilization of vision at 20/25- and 20/100, respectively. In one patient, vision has been stable at 20/50 for 6 months; however, a recurrent subretinal neovascular membrane developed, encroaching through the fovea with resultant visual loss of 20/60.

Adult↗

PubMed1983

[Lung cancer].

Lung cancer is characterized by a varied histologic background and as a result has a wide range of histologic types compared to cancer of other organs. There is remarkable difference in malignancy according to histologic type, therefore a definitive diagnosis before treatment is essential to determine therapeutic strategy. Recently definitive diagnostic rates of 99% have been obtained by various diagnostic procedures. The value of surveys especially those including sputum cytology is discussed. Also laser therapy with Nd-YAG laser and/or administration of hematoporphyrin derivative plus photoradiation by an argon dye laser and tumor localization with fluorescence photoradiation by a krypton ion laser are discussed.

Adenocarcinoma↗

PubMedDate not supplied

The medical laser: an indispensable tool of the physician and surgeon.

The enormous proliferation of developments in the field of lasers has brought many changes and improvements to medicine. Lasers generate electromagnetic radiation unique in nature: Their light is coherent, collimated, and monochromatic. Because of these qualities, laser rays can be focused to very small spots of enormous power density. The wavelengths produced by a particular type of laser are determined by the characteristic energy levels of the emitting elements in the laser medium. The wavelengths of lasers currently used in therapy and surgery range from about 400 nm to 10,600 nm; at surgical power densities and at these wavelengths, because photonic ionization of atoms does not take place, laser rays are not oncogenic. Lasers can be used for converting radiant energy into heat in living tissues, for stimulating or moderating chemical reactions, or for mechanically disrupting histologic structure. Argon-ion, carbon dioxide, helium-neon, neodymium-doped yttrium-aluminum-garnet, ruby, organic-dye, and krypton-ion lasers are frequently used in medicine for therapeutic, analytical, or surgical applications. Laser use in medicine will increase as new developments bring forth new applications.

Biophysical Phenomena↗

PubMed1983

[Treatment of zoster, post-zoster pain and herpes simplex recidivans in loco with laser light].

Red light of a krypton laser (lambda = 647 nm) was used for treatment of patients suffering from herpes zoster (n = 4), postherpetic neuralgias (n = 8) and herpes simplex recidivans in loco (n = 13). The afflicted skin was irradiated daily for ten days (laserpower 50 mw, exposure time 90 sec). Improvement was observed in 7 out of the 12 patients suffering from herpes zoster and postherpetic neuralgias respectively, and in 8 out of 13 patients afflicted with recurrent herpes simplex.

Aged↗

PubMed1981

Presumed ocular histoplasmosis.

Six patients showing typical manifestations and some rare features of the presumed ocular histoplasmosis syndrome are presented and discussed in the light of present knowledge. Krypton laser photocoagulation was used in one patient with encouraging results. Histoplasmin skin testing was negative in all cases. HLA typing supported the previous findings of an association with HLA B7 but not DRw2. Although the presumed ocular histoplasmosis syndrome is not uncommon outside America the true aetiology of this condition remains obscure.

Adult↗

PubMed1978

Effects of nifedipine on creatine kinase release during myocardial ischemia in dogs.

25 anesthetized mongrel dogs underwent a left thoracotomy. Creatine kinase (CK) activity was measured in serial blood samples drawn simultaneously from the aorta and a coronary vein. The distribution of myocardial perfusion was determined by a continuous infusion of krypton-81m (half-life 13 sec) into the aortic sinuses. Heart rate and arterial blood pressure were also measured throughout the procedure. In 20 dogs regional myocardial ischemia was produced by ligation of a major branch of the left anterior descending coronary artery. Five of these dogs received 1 microgram.kg-1 nifedipine i.v. and a further 5 received 13 microgram.kg-1. Thoracotomy alone produced a slight rise in plasma CK activity but the arteriovenous difference (AV) across the segment of the heart remained positive over 5 h. Myocardial ischemia in the untreated dogs caused a considerable increase in CK activity and the AV difference became negative at 90 min. Treatment with the lower dose of nifedipine considerably reduced the plasma CK activity and the AV difference did not become negative until 3 h. Regional myocardial perfusion showed a significant improvement. Conversely, the higher dose of nifedipine produced a marked increase in the area of ischemia and an acceleration of CK release from the heart. This was associated with a decrease in arterial pressure and an increase in heart rate. These results show that nifedipine can be beneficial in experimental myocardial infarction but care must be taken to avoid hypotension and increases in heart rate.

Animals↗

PubMed1980

[Pulmonary embolism in leg and pelvic vein thrombosis. Results of a prospective study - diagnosis, frequency, nuclearmedical and clinical appearance (author's transl)].

In a prospective study 169 patients with clinically suspected leg/pelvic-vein thrombosis were tested by 131 I fibrinogen uptake-test and radionuclide venography for confirmation of this diagnosis and also by a nuclearmedical lung investigation. In all cases of an abnormal perfusion scan a supplementary ventilation scan was performed. The perfusion scan has a sensitivity for pulmonary embolism of near 1.0 but its specificity is only 0.57. An additional ventilation study (133 Xenon, 81m Krypton) improves the specificity to 0.95. A mismatch of regional ventilation and perfusion is the nuclearmedical substrate of pulmonary embolism. The diagnosis of thrombosis was confirmed in 105 of 169 cases (62%). Thrombosis was located in the lower legs in 56%, in the thigh veins in 23% and in the external iliac veins in 21%. From 105 patients with leg/pelvic-vein thrombosis 60 (57.1%) had pulmonary emboli, from 64 patients with negative tests concerning thrombosis only 3 (4.7%) (p < 0.001). Pulmonary emboli were present in 46% when thrombosis was located in the lower legs, in 67% when thigh veins and in 77% when pelvic veins were involved. The average frequency of 57% emboli found in patients with leg and pelvic vein thrombosis agrees with data from pathologic-anatomical studies. An analysis of these patients with embolism showed that 70% of them were over 70 years old, that 52% of the emboli originated from thigh and pelvis and 43% from the lower leg and that 59% had no clinical signs of embolism. 80.4% of the patients had multiple perfusion defects (up to 9) which correlated in size with the severity of the clinical symptoms and which were about equally distributed in both lungs. Larger perfusion defects occure more frequently with thromboses of the thigh and pelvis than in thromboses of the lower leg. According to the chest x-ray pulmonary emboli were suspected to only 6 of 26 patients with clinical evidence of embolism (23%).

Adult↗

PubMed1996

Detection of early bladder cancer by 5-aminolevulinic acid induced porphyrin fluorescence.

PURPOSE: We determined whether the sensitivity of detecting dysplasia or early bladder cancer can be improved by 5-aminolevulinic acid induced porphyrin fluorescence. MATERIALS AND METHODS: A 3% 5-aminolevulinic acid solution was instilled intravesically before cystoscopy in 104 patients. The 5-aminolevulinic acid induced porphyrin fluorescence was excited by violet light from a krypton ion laser (wavelength 406.7 nm.). RESULTS: The sensitivity of the fluorescence cystoscopy (96.9%) was significantly (p < 0.0001) greater than that of white light cystoscopy (72.7%). There was no impact on specificity. CONCLUSIONS: Due to the high sensitivity of the procedure fluorescence guided biopsies are recommended instead of random biopsies.

Administration, Intravesical↗

PubMed1994

Laser photocoagulation for juxtafoveal choroidal neovascularization. Five-year results from randomized clinical trials. Macular Photocoagulation Study Group.

OBJECTIVE: To summarize findings from three randomized clinical trials of krypton laser treatment of juxtafoveal neovascular lesions regarding changes in visual acuity during 5 years of follow-up, rates of persistent and recurrent choroidal neovascularization, and status of macular lesions 5 years after enrollment. DESIGN, PATIENTS, AND PRIMARY OUTCOME MEASURES: Follow-up of patients enrolled in three randomized trials of choroidal neovascularization secondary to age-related macular degeneration (AMD), ocular histoplasmosis, or idiopathic causes ended in March 1991. All patients were eligible to complete at least 3 years of follow-up examinations. Data on visual acuity, reading vision, and anatomic outcomes during 5 years of follow-up were available for 276 (92%) of 300 patients with AMD, 236 (92%) of 256 patients with ocular histoplasmosis, and 38 (97%) of 39 patients with idiopathic choroidal neovascularization enrolled 5 or more years earlier who were still living. RESULTS: Among eyes with AMD, the estimated relative risk (RR) of a loss of 6 or more lines of visual acuity from baseline to any examination from 6 months through 5 years after enrollment for untreated eyes in comparison with treated eyes was 1.20 (P = .04). Normotensive patients with AMD realized the greatest benefit from laser treatment (RR, 1.82) and hypertensive patients experienced little or no benefit (RR, 0.93). Untreated eyes with ocular histoplasmosis were at much greater risk of a 6-line decrease in visual acuity from the 1-year through the 5-year examination than were treated eyes (unadjusted RR, 2.60; RR, 4.26 after adjustment for visual acuity and hypertension at baseline; P < .001 for both). The treatment effect for eyes with idiopathic choroidal neovascularization was between the effects for eyes with AMD and eyes with ocular histoplasmosis. CONCLUSIONS: The early beneficial effects of laser treatment on visual acuity persisted for at least 5 years in eyes with all three underlying conditions. Laser treatment of similar eyes with choroidal neovascularization in a juxtafoveal location is recommended for patients with these conditions, with the caveat that hypertensive patients with AMD may fare no better with laser treatment than without treatment.

Aged↗

PubMed1994

Growth factor localization in choroidal neovascular membranes of age-related macular degeneration.

PURPOSE: Because several polypeptide growth factors are known to influence capillary endothelial cell mitogenesis, the authors investigated the presence of some of these molecules in choroidal neovascular membranes (CNVMs) removed surgically from human subjects with age-related macular degeneration (ARMD). METHODS: The authors performed immunoelectron microscopic studies on surgically removed submacular CNVMs from nine subjects with ARMD and from one subject with ARMD whose eye was studied after death. These were compared with retinal pigment epithelial (RPE) and choroidal tissue from eight normal subjects whose eyes were received after death and one received after massive trauma. RESULTS: RPE cells from the CNVMs were strongly immunoreactive for acidic and basic fibroblast growth factor (aFGF and bFGF) and for transforming growth factor beta (TGF beta). Some of the immunoreactivity was intracytoplasmic, but most was intralysosomal. In addition, some choriocapillary endothelial cells located close to the RPE layer in these CNVMs were immunopositive for bFGF and for FGF receptor. Reaction product for these two substances was located at regular intervals along the endothelial plasma membrane on both the anteluminal and the luminal side of the cells, suggesting a physiological reaction between the growth factor and its receptor. Choriocapillary endothelial cells deeper within the stroma were unreactive to bFGF and FGF receptor antibodies. There was little immunoreactivity for the growth factors in RPE or choriocapillary endothelial cells from normal eyes. The aFGF and bFGF immunoreactivity was highly specific because aFGF positivity was abolished when the antibody was incubated with 10(-6) M aFGF but not a with the same concentration of bFGF, whereas bFGF immunoreactivity was abolished by incubation of the antibody with bFGF but not with aFGF. RPE cells from normal eyes and from eyes affected by ARMD showed strong cytoplasmic immunoreactivity to antibodies for cytoplasmic retinaldehyde-binding protein and superoxide dismutase and weak reactivity to antibodies for vimentin. CONCLUSIONS: These results are consistent with the hypothesis that one or both FGFs are causally related to the development of choroidal neovascularization. The authors have reported similar observations in experimental choroidal neovascularization in pigmented rats after red krypton laser photocoagulation. TGF beta may serve to modulate the effects of these mitogens. The authors suggest that growth factor production is induced in RPE cells after physical or chemical damage. Because of the damage to these cells, FGF molecules can be released from the cells despite the absence of a "signal sequence" in the DNA coding for FGF production.

Aged↗

PubMed1995

[Expression of fibroblast growth factor receptor 1 in experimental choroidal neovascularization with in situ hybridization].

Fibroblast growth factor (FGF) is an important factor for neovascularization in vivo. In order to clarify the role of FGF in experimentally produced choroidal neovascularization, we demonstrated mRNA for FGF receptor 1 in situ hybridization. Krypton laser photocoagulation was applied to the posterior retina of colored rats to produce choroidal neovascularization experimentally. These eyes were removed at several different intervals after photocoagulation. Chorioretinal section were used for in situ hybridization. FGF receptor 1 cDNA fragment was used to make antisense and sense probes for in situ hybridization. In normal chorioretinal tissue, staining indicating the existence of FGF receptor 1 mRNA was seen in the ganglion cell layer and inner nuclear layer. After the photocoagulation, the staining was seen in the retinal pigment epithelial cells, melanocytes in the choroid, and choroidal blood vessel wall in the photocoagulated lesions. FGF receptor 1 mRNA was expressed through the development of choroidal neovascularization, and it appears that FGF is necessary for development of choroidal neovascularization. Previous workers showed that the capillary endothelial cells and retinal pigment epithelial cells produce basic FGF in vitro. It seems that FGF effects those cells in an autocrine or paracrine manner in vivo.

Animals↗

PubMed1995

[A long-term course of experimentally produced choroidal neovascularization in the rat].

We studied morphologically a long-term course of experimental choroidal neovascularization (ChNV) induced by krypton laser photocoagulation in the rat retina. Fifty-two weeks after photocoagulation, ChNV was enveloped completely by the retinal pigment epithelium. Vascular endothelial cells of ChNV were thin, with many fenestrations and wide lumen. The ChNV maintained the morphological characteristics of mature leaky capillaries similar to choriocapillaris. The lumen of the neovascularizations tended to be compressed by massive collagen fibers produced by the retinal pigmented epithelium. We found that experimental ChNV in the rat retina retains the characteristics of leaky capillaries for a long time unlike that in the monkey ChNV.

Animals↗

PubMedDate not supplied

[Vitreous hemorrhage: attitudes in therapy, vitrectomy].

Vitreous haemorrhage is a serious complication of proliferative diabetic retinopathy: it provides evidence of the severity of at proliferative retinopathy at stake and precludes laser photocoagulation. In some cases of moderate vitreous haemorrhage, panretinal photocoagulation remains possible especially using longer wavelengths such as krypton red; cryotherapy under ophthalmoscopic control may be an alternative to panretinal photocoagulation. Development of pars plana vitrectomy, however, has been the main break the rough in the management of severe vitreous haemorrhage. Pars plana vitrectomy was first reserved to massive, long-standing vitreous haemorrhage; improvements in instrumentation and techniques, as well as observations of the favourable effect of vitrectomy on the progression of proliferative retinopathy led to enlarged indications for pars plana vitrectomy. Beyond severity and duration of visual loss, main arguments for pars plana vitrectomy are bilaterality, lack of previous panretinal photocoagulation, iris neovascularization, Type 1 diabetes, and severity of fibrovascular proliferation.

Cryotherapy↗

PubMed1994

[Post-laser choroidal hematoma in a diabetic patient treated with an oral anticoagulant].

We report a case of a 45 year old diabetic man treated with insulin who developed a right choroidal hematoma after krypton laser treatment for proliferative retinopathy. This patient had a history of myocardial infarction and had been treated with oral anticoagulants for 3 years. Choroidal hematoma was associated with vitreous hemorrhage and presumed herpetic uveitis. Since the retina could not be visualized the diagnosis was based on ultrasound findings. Irreversible blindness of the affected eye occurred. In this case report, oral anticoagulant treatment seems to be the major risk factor leading to the development of this unusual hemorrhagic complication of panretinal photocoagulation. To avoid this serious accident, patients submitted to long-term oral anticoagulant treatment should be managed with particular caution before and during photocoagulation.

Administration, Oral↗

PubMed1993

[The effect of corticosteroid on the repair of the retinal pigment epithelium].

The effect of corticosteroid on the repairing process of the retinal pigment epithelial cells (RPE) after laser photocoagulation was investigated. Mild-intensity krypton red laser photocoagulations were performed on the monkey retina. After laser photocoagulations, betamethasone (0.5 mg/kg) were administered intramuscularly every day for 1-14 days. Moreover, the same doses of betamethasone were also administered intramuscularly for one week from the 1st to 7th day after laser photocoagulation on other monkeys. The photocoagulated lesions were observed with light and transmission electron microscopy. In monkeys that received corticosteroids, the migration and the proliferation of RPE were markedly inhibited, and the metaplasia to fibroblast-like cells of RPE was not observed. These results showed that large doses of corticosteroid inhibited the repair process of the injured RPE.

Animals↗

PubMed1993

[Laser photocoagulation treatment of small malignant choroidal melanomas].

8 cases of malignant choroidal melanoma were treated with argon and krypton laser photocoagulation of average 11 sessions and followed up an average 56 months. Clinical complete regression was observed in 5 cases (62.5%), in whom the tumors measured from 1.0mm x 1.2mm x 1.5mm to 6.0mm x 4.5mm x 2.5mm. The other 3 cases (37.5%) recurred, in whom the tumors measured from 4.0mm x 2.0mm x 3.5mm to 11.5mm x 12.5mm x 3.5mm. The complications of treatment included branch retinal vein occlusion, retinal neovascularization, vitreous hemorrhage, macular edema and optic atrophy. These results suggested that laser photocoagulation was useful in the treatment of small malignant choroidal melanomas.

Adult↗

PubMed1993

[Use of diode laser in transcleral retinal photocoagulation].

Transscleral retinal photocoagulation using a diode laser emitting infrared radiation (810 nm) was performed on 8 rabbits. Examination was performed at 2 days, one month and three months after photocoagulation. The retinal burns were examined by light and electron microscopy and were found to be similar to those produced by argon and krypton photocoagulations. Histopathologic evaluation of the lesions demonstrated an intact sclera overlying the chorioretinal lesions. The results of the present experimental study support the hypothesis that transsccleral retinal photocoagulation using diode laser in selected indications may be a valuable alternative to cryotreatment and diathermy in the human eye. The absence of scleral damage and pigmented epithelium cell dispersion as well as the decreased break down of the blood ocular barrier after transscleral diode laser photocoagulation are the main advantages of the technique as compared to transscleral diathermy and cryotreatment.

Animals↗

PubMed1993

[Early diagnosis of gastric cancer].

Endoscopic diagnosis completed by biopsy achieved remarkable accuracy. New trends--endoscopy with the use of ultrasound orange red porphyrin fluorescence elicited by blue light e. g. krypton laser and strip biopsy not only greater accuracy of endoscopic methods but also open up new therapeutic possibilities. Histochemical and histoenzymatic methods allow to classify histological findings of the norm (presence of pepsinogen and neutral glycoprotein) of atrophic gastritis with intestinal metaplasia (acid glycoprotein, activity of sucrose, alkaline phosphatase-AP, leucin-aminopeptidase-LAP) and of dysplasia (presence of sulfomucin, decrease of AF, LAP, sucrose and trehalase activity) and to divide them into well defined groups. We are able to distinguish which mucosal changes are suspect, we know that malignant transformation can after a certain period of time be expected approximately 2-14% yet we still do not know whether the period from dysplastic change to malignant transformation is not longer than malignant change in resected stomach. Epidemiologic and experimental data gives us enough reasons for dietary and chemopreventive measures (apart of other treatment) especially in risk groups patients.

Humans↗