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R Schalnus

Publications and source records attributed to R Schalnus.

At least 19 recordsLinked to original sources

Aqueous flare in retinitis pigmentosa.

BACKGROUND: The purpose of this study was to quantify blood-ocular barrier impairment by measuring aqueous flare in retinitis pigmentosa (RP) and to search for clinical correlations. METHODS: Forty-nine patients (94 eyes) with RP and 85 normal controls were examined. Aqueous flare was quantified with the noninvasive laser flare-cell meter (FC-1000, Kowa, Japan). Degrees of cystoid macular edema (CME), vitreous pigment dusting (VPD), intraretinal migration of retinal pigment epithelium, and waxy pallor of the optic nerve head were determined semiquantitatively by biomicroscopy. Data were analyzed using the t-test the Mann-Whitney U-test, the chi-squared test and regression analysis by taking into account the dependency of data from two eyes of the same patients. RESULTS: Aqueous flare (photon counts/ms) was significantly higher in RP (mean 10.11 +/- 3.53) than in normals (3.89 +/- 0.94; P < 0.001). Clinically significant CME was present in 26% of eyes with RP, being significantly more frequent in autosomal dominant RP (11 of 16 eyes, 69%) than in other variants (17%; P < 0.005). Multivariate analysis revealed that CME was most strongly associated with flare values (r = 0.84), P < 0.01), whereas--after adjusting for CME--correlations between aqueous flare and other clinical findings did not reach significance. CONCLUSION: RP eyes show increased aqueous flare values, indicating impairment of blood-occur barriers. This appears to be associated with CME and with autosomal dominant RP.

Adolescent↗

Permeability of the blood-retinal barrier in healthy humans. European Concerted Action on Ocular Fluorometry.

BACKGROUND: The aim of this study was to compare the inward permeability of the blood-retinal barrier in healthy subjects from six European cities. METHODS: Seventy-two healthy subjects (age 20-70 years) were selected. At 30 min and 60 min after fluorescein injection, fluorescein mass in vitreous was calculated from the concentrations measured along the optical axis of the eye. Non-protein-bound fluorescein (NPBF) concentrations were measured in plasma prepared from blood samples taken 7, 15 and 55 min after injection. Blood-retinal barrier permeability (PBRB) was calculated from the vitreous fluorescein mass and the time integral of NPBF and was corrected for the autofluorescence of ocular tissue and for lenticular light transmittance. RESULTS: Mean PBRB values +/- SD (nm.s-1) were 2.07 +/- 0.54 (Coimbra), 2.01 +/- 0.43 (Frankfurt), 2.24 +/- 0.50 (Ghent), 2.37 +/- 0.56 (Herlev), 1.89 +/- 0.44 (Leiden) and 1.74 +/- 0.38 (Porto). Differences between centers were not significant (P > 0.35). Measurements were reproducible and independent of the time after fluorescein injection (P > 0.50). A PBRB higher than 3.16 nm.s-1 or a value which had increased by 32% was considered abnormal (P < 0.05). CONCLUSION: PBRB values were similar in all centers. The results demonstrate that this is a highly sensitive and reliable method for measuring the permeability of the blood-retinal barrier.

Adult↗

[Corneal topography after cataract surgery with tunnel incision on a steeper meridian in inverse and oblique astigmatism].

Scleral tunnel incision at the 12 o'clock-position for no-stitch cataract surgery can increase preexisting against-the-rule astigmatism by flattening the vertical corneal meridian. An oblique axis can change by operative induction. We investigated, in a prospective study, whether reduction of such a preoperative astigmatism could be induced by locating the tunnel incision on the steeper meridian. Eighteen eyes with senile cataract and against-the-rule or oblique astigmatism of at least 0.7 diopters were operated with a standardized 5 x 6 mm scleral tunnel incision and a 6 mm PMMA posterior chamber lens. We evaluated the astigmatism with a videokeratoscopy TMS-I preoperatively and about 6 months after the surgery. The mean corneal astigmatism was 1.8 diopters pre- and 1.5 diopters postoperatively. A reduction of keratometric astigmatism was reached in 72% of cases; 17% remained unchanged. The surgically induced astigmatism calculated by Jaffer's and Clayman's vector analysis was 0.68 diopters. The technique of scleral tunnel incision with lateral or oblique approach can reduce a preexisting against-the-rule or oblique astigmatism.

Astigmatism↗

[Intraocular rt-PA injection in fibrin formation after combined glaucoma and cataract operation].

BACKGROUND: The fibrinolytic drug rt-PA, which has been successfully used systemically to treat arterial and venous occlusions, is now available for local, intraocular injection. rt-PA converts plasminogen to plasmin, which in turn is able to lyse fibrin and fibrin clots. Intraocular surgery, trauma and inflammation may lead to intraocular accumulation of fibrin. Treatment of this type of complication with high-dose corticosteroids is protracted and often unsuccessful. PATIENTS: Eight patients (age 59-75 years) with fibrin formation following phacoemulsification and IOL implantation combined with trabeculectomy were treated by intraocular injection of 10 micrograms rt-PA. The intraocular status following the local fibrinolytic therapy was documented by biomicroscopy, photography and laser-flare Tyndallometry on days 1, 2 and 8. RESULTS: In all patients the fibrin clots dissolved completely. Neither relapses nor adverse affects were noted. CONCLUSIONS: The intraocular application of rt-PA results in an efficient fibrinolytic effect, which prohibits potential complications of combined glaucoma and cataract surgery due to fibrin formation.

Aged↗

Diffusion coefficient through the blood-aqueous barrier using a standard protocol.

AIMS/BACKGROUND: Comparison of the diffusion coefficient through the blood-aqueous barrier of healthy volunteers measured in different cities with identical fluorophotometers using a standardised protocol. METHODS: Healthy volunteers aged between 20 and 70 years were studied in seven European cities. The fluorescein concentration in the anterior segment of each eye was measured with a commercial scanning fluorophotometer 30 and 40 minutes after intravenous fluorescein. The decay of non-protein bound fluorescein concentration in blood plasma was determined with the use of three blood samples taken at 7, 15, and 55 minutes after injection. The diffusion coefficient through the blood-aqueous barrier was calculated from the ratio between the fluorescein concentration in the anterior chamber and the time integral of non-protein bound fluorescein concentration in plasma using specially developed software. RESULTS: The mean values of the diffusion coefficient (SD) (X10(-4) min-1) were 4.76 (1.51) (n = 20, Brussels), 5.48 (2.33) (n = 17, Coimbra), 3.47 (2.09) (n = 12, Cologne), 6.09 (2.77) (n = 21, Frankfurt), 3.85 (1.59) (n = 11, Ghent), 4.99 (1.69) (n = 23, Leiden), and 4.87 (1.05) (n = 20, Madrid). The values between centres were similar (Kruskal-Wallis test p > 0.05) except for Cologne and Frankfurt (p = 0.013). No differences were found when repeating measurements (four centres, interval time 1-8 months, Wilcoxon paired test p > 0.39). CONCLUSION: The diffusion coefficients had similar values and standard deviations. The concerted action demonstrated the usefulness of a standardised protocol.

Adult↗

Corneal endothelial permeability and aqueous humor flow using a standard protocol.

BACKGROUND: The study was carried out to compare corneal endothelial permeability and aqueous flow values of healthy volunteers measured in different countries with identical fluorophotometers using a standardized protocol. METHOD: Healthy volunteers aged between 20 and 70 years were studied in five European cities. Fluorescence scans of the anterior segment of both eyes were made using a commercial fluorophotometer. Beginning 4 h after instillation of four drops of fluorescein 10%, 12 scans of the anterior segment of each eye were performed in 2 h. The values of corneal endothelial permeability and aqueous flow were calculated with standardized software from the decay of the fluorescein concentration in the cornea and anterior chamber. RESULTS: The mean permeability values (x 10(-4) cm.min-1) +/- SD were 3.7 +/- 1.6 (n = 19; Coimbra, Portugal), 4.3 +/- 1.1 (n = 19; Frankfurt, Germany), 3.9 +/- 0.9 (n = 19; Leiden, The Netherlands) and 5.4 +/- 1.2 (n = 10; Milan, Italy). The values were not significantly different (ANOVA, P > 0.3), except those in Milan. The mean flow values (microliters.min-1) +/- SD were 2.3 +/- 0.9 (n = 17; Coimbra), 1.9 +/- 0.7 (n = 10; Cologne, Germany), 2.6 +/- 1.2 (n = 19; Frankfurt), 2.0 +/- 0.6 (n = 19; Leiden) and 1.7 +/- 0.8 (n = 10; Milan). The values were not significantly different (Kruskal-Wallis test, P > 0.1). CONCLUSIONS: Permeability and flow values in the different cities had similar values and standard deviations. The Concerted Action demonstrated the usefulness of a standardized protocol.

Adult↗

The blood-ocular barrier in type I diabetes without diabetic retinopathy: permeability measurements using fluorophotometry.

For the evaluation of a possible malfunction of the blood-retinal (BRB) and the blood-aqueous barrier (BAB) in type I diabetes without manifest angiopathy, after i.v. injection of sodium fluorescein, the permeability of BRB (P) and the diffusion coefficient of BAB [P(a)] were studied simultaneously by fluorophotometry in 34 eyes of 34 type I diabetics (HbA1c = 6.6 +/- 0.9%) without retinopathy whose ages ranged from 19 to 38 years (30.5 +/- 5); diabetes' duration was between 5 and 18 years. Fluorescein angiography was performed to exclude nonperfused areas. In all, 34 eyes of 34 healthy volunteers whose ages ranged between 23 and 34 years (28.5 +/- 3.3) served as controls; in this group, fluorophotometry was performed twice to evaluate reproducibility. The mean BAB diffusion coefficient in diabetics [P(a) = 5.3 +/- 1.8/min] was significantly increased (p = 0.00003) as compared to controls [P(a) = 3.7 +/- 0.7/min]; BRB permeability in diabetes (P = 3.2 +/- 1.4 x 10(-7) cm/s) was raised with this elevation being of lower significance (p = 0.019; controls: P = 2.6 +/- 0.7 x 10(-7) cm/s). We found a decrease in BRB permeability depending on diabetes' duration (r = -0.15; p = 0.007) that was not significant in BAB (r = -0.1; p = 0.24). No correlation was found to exist between permeability and HbA1c values either in BAB or in BRB. The reproducibility in controls was 9% in BRB determinations and 12% in BAB measurements. These results may suggest that early structural alterations without the manifestation of retinopathy possibly cause elevation in BRB permeability and are even more obvious in BAB permeability. Whereas the reliability of vitreous fluorophotometry in detecting early BRB malfunction has to be judged critically, anterior segment fluorophotometry is a reliable procedure for the monitoring of BAB affection in type I diabetes without retinopathy.

Adult↗

[Balloon dilatation of relative postsaccal lacrimal duct stenoses].

In ten patients with incomplete postsaccal stenosis radiology examined by digital subtraction dacryocystorhinography, an overpressure ballooning was done with a small foot vessel balloon with hydrophilic surface under image intensiver control. The balloon was inflated with a diluted suspension for visualization of the balloon and widening of the stenosis. In eight patients recovery was continuous without any treatment, in one with topical application of vasoconstrictor eye drops. In one patient there was a recurrence. Balloon of incomplete postsaccal lacrimal pathway dilatation stenosis is an adequate and minimally invasive therapy.

Angiography, Digital Subtraction↗

[Quantification of disorders of the blood-aqueous humor barrier in retinitis pigmentosa--initial results].

BACKGROUND: Clinical findings in patients with retinitis pigmentosa (RP) frequently include cystoid macular edema (CME) and vitreous pigment dusting (VPD) indicating alterations of the blood-ocular barriers. It was the aim of this study to determine whether alterations of the blood-aqueous barrier (BAB) are present in RP. PATIENTS AND METHODS: Aqueous flare was quantitatively determined in 56 eyes of 29 patients (mean age 36.4 +/- 11.2 years) with RP using the noninvasive laser flare-cell photometer (Kowa FC-1000, Tokyo, Japan). All RP patients had common forms of RP with markedly reduced or nondetectable ERG. The presence of CME and VPD was determined semiquantitatively by biomicroscopy. Fifty-eight eyes of 58 normal controls (mean age 38.2 +/- 8.5 y.) were also examined. RESULTS: Aqueous-flare values were significantly higher in RP eyes (mean 9.65 +/- 3.24 photon counts/ms, range 4.0-18.1) than in the normal control eyes (mean 3.89 +/- 1.05, range 1.9-6.0, p < 0.0001, Mann-Whytney test). Forty-eight of the 56 RP eyes (86%) showed increased flare values (> 6.0 photon counts/ms). RP eyes with moderate to marked CME (n = 11) had significantly higher flare values (mean 14.66 +/- 1.92) than RP eyes without or with only questionable CME (8.52 +/- 2.18, p < 0.0001), and RP eyes with moderate to marked VPD (n = 17) had significantly higher (12.05 +/- 2.84) flare values than RP eyes without or with only minimal VPD (8.74 +/- 2.22, p < 0.0005). CONCLUSIONS: Our findings show that the majority of patients with RP have alterations of the BAB with consecutively increased aqueous protein concentrations. The impairment of the BAB appears to be associated with CME and VPD. Measurement of aqueous flare in RP allows quantification of the impairment of the BAB and may be helpful in the future in choosing and monitoring patients with RP and CMP for possible antiinflammatory or antiedematous therapeutic measures.

Adult↗

[The blood-retina barrier and blood-aqueous humor barrier in type I diabetic patients without retinopathy. Determination of permeability using fluorophotometry and laser flare measurements].

BACKGROUND: Possibly early functional disruption of the blood-ocular barrier in eyes of insulin dependent type I diabetics without manifestation of retinopathy can be detected using fluorophotometry and laser flare measurement. MATERIAL AND METHODS: In order to evaluate blood-retinal (BRB) and blood-aqueous-barrier (BAB) permeability fluorophotometry was performed in 34 eyes of 34 insulin-dependent type-I diabetics without retinopathy, additionally the aqueous laser flare was measured. 34 normal eyes of 34 age-matched subjects served as controls. RESULTS: BRB permeability (3.2 +/- 1.3 x 10(-7) cm/s) was increased with low significance (p = 0.019) in diabetic eyes (controls: 2.6 +/- 0.7). The permeability coefficient of BAB was found to be increased in diabetics (5.3 +/- 1.8 x 10(-4)/cm) with higher significance (controls: 3.7 +/- 0.7; p = 0.00003); laser flare values in diabetic eyes (5.0 +/- 1.2 photon counts/ms) were significantly higher than in controls (4.1 +/- 1.0; p = 0.003). In diabetics there was a significant correlation (r = 0.3; p = 0.014) between the laser flare values and the permeability coefficient of BAB. CONCLUSIONS: In type-I diabetics without retinopathy BRB permeability seems to be increased slightly as well as laser flare in the aqueous; the BAB permeability coefficient seems to be the most sensitive parameter in a beginning affection of the blood-ocular barrier.

Adult↗

Permeability of the blood-retinal barrier and the blood-aqueous barrier in type I diabetes without diabetic retinopathy: simultaneous evaluation with fluorophotometry.

For the evaluation of a possible malfunction of the blood-retinal barrier (BRB) and the blood-aqueous barrier (BAB) in type I diabetes without manifest angiopathy after i.v. injection of sodium fluorescein, the permeability of the BRB (P) and the permeability coefficient of the BAB [P(a)] were simultaneously determined by fluorophotometry in 34 eyes of 34 type-I diabetics [hemoglobin (Hb)A1c = 6.6% +/- 0.9%] without retinopathy whose age ranged from 19 to 38 years (mean, 30.5 +/- 5 years); the diabetes duration was between 5 and 18 years. Fluorescein angiography was performed to exclude nonperfused areas. In all, 34 eyes of 34 healthy volunteers whose age ranged between 23 and 34 years (mean, 28.5 +/- 3.3 years) served as controls; in this group, fluorophotometry was performed twice to evaluate reproducibility. The mean BAB permeability coefficient in diabetics [P(a) = 5.3 +/- 1.8 x 10(-4)/min] was significantly increased (P = 0.00003) as compared with control values [P(a) = 3.7 +/- 0.7 x 10(-4)/min]; BRB permeability in diabetics (P = 3.2 +/- 1.4 x 10(-7) cm/s) was raised, with this elevation being of lower significance (P = 0.019; controls, P = 2.6 +/- 0.7 x 10(-7) cm/s). We found a decrease in BRB permeability depending on diabetes duration (r = -0.15; P = 0.007) that was not significant in the BAB (r = -0.1; P = 0.24). No correlation was found to exist between permeability and hemoglobin (Hb)A1c values either in the BAB or in the BRB. The reproducibility in controls was 9% in BRB determinations and 12% in BAB measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Quantification of blood-aqueous barrier function using laser flare measurement and fluorophotometry--a comparative study.

Fluorophotometry allows calculation of the permeability coefficient k(a) of the blood-aqueous barrier to fluoresceine after i.v. dye application; aqueous flare can be graded objectively by laser flare measurement and permits in vivo estimation of over-all protein concentration in the aqueous humor. To evaluate a formal relationship between both procedures we performed laser flare measurements on 40 eyes (clinically ranged from healthy to mild uveitis) before and during fluorophotometry. Laser flare count [mec-1] raises exponentially (r = 0.8; p = 0.05) with an increasing permeability coefficient to fluoresceine k(a) [10(-4)min-1]. Laser flare count during the fluorophotometry procedure is not increased (p = 0.05) compared to the prescan. Reproducability was 14% +/- 7.5% for laser flare measurements and 13% +/- 5% for fluorophotometry. Malfunction of the blood aqueous barrier possibly increases the permeability to molecules of high molecular weight not proportional to that of hydrophilic particles of low molecular weight. The exponential regression between the data achieved with both procedures suggests that fluorophotometry is more sensitive in detecting early changes in blood aqueous barrier function whereas laser flare detection could be appropriate in more severe cases of barrier dysfunction.

Adult↗

[Therapeutic alternative or 2d choice drug. Trisodium phosphonoformate in cytomegalovirus retinitis].

From 01. 01. 1988 to June 1990, a total of 275 patients with AIDS had been examined in our ophthalmological out-patient clinic. The clinical diagnosis of a cytomegalovirus (CMV) retinitis was recorded in 56 of these patients (= 20.1%). The initial therapy, as usual, took the form of infusions of the virustatic drug ganciclovir at an induction dose of 10 mg/kg body weight per day (3 weeks), with a maintenance dose of 3.5-5 mg/kg body weight per day (5 days per week) thereafter. During maintenance therapy recurrences were observed in 15 cases and herpes simplex retinitis in 3, with progressive retinal destruction. Therefore we began treatment with trisodium phosphonoformate (Foscavir) at a dosage of 60 mg/kg body weight per day (3 weeks), continuing with maintenance therapy at 90 mg/kg body weight per day (7 days a week). After the induction dose 14 patients showed subjective improvement and satisfactory cicatrization of the retinal lesions. We monitored the retina by a standardized method and 50 wide-angle retinal photographs. One case of acute retinal necrosis (ARN) did not show any response to foscavir therapy. Typical side-effects of therapy with trisodium phosphonoformate were seldom seen: adverse events included renal dysfunction, neutropoenia, and asymptomatic hypocalcaemia. We conclude that trisodium phosphonoformate is an effective and well-tolerated agent for the treatment and prevention of relapse of CMW retinitis and can be used as an alternative ganciclovir.

Acquired Immunodeficiency Syndrome↗

Modulation of 5-hydroxytryptamine release by presynaptic inhibitory alpha 2-adrenoceptors in the human cerebral cortex.

Slices and synaptosomes from human cerebral cortex (which had to be removed to reach deeply located tumours) and, for comparison, synaptosomes from guinea-pig and rat cerebral cortex were preincubated with [3H]5-hydroxytryptamine and superfused with physiological salt solution containing an inhibitor of 5-hydroxytryptamine uptake. The effects of alpha-adrenoceptor agonists and antagonists on the electrically (slices) or potassium-evoked (synaptosomes) tritium overflow were studied. In human cerebral cortical slices, the electrically-evoked [3H] overflow was inhibited by noradrenaline (pIC25 value: 6.35); the non-selective alpha-adrenoceptor antagonist phentolamine, at a concentration of 0.32 mumol/l, strongly antagonized the inhibitory effect of noradrenaline (apparent pA2 value: 8.19) but did not affect the evoked overflow by itself. In synaptosomes from humans, guinea-pigs and rats, noradrenaline also inhibited the K(+)-evoked [3H] overflow in a concentration dependent manner; the alpha 2-adrenoceptor clonidine (1 mumol/l), but not the alpha 1-adrenoceptor agonist methoxamine (1 mumol/l), mimicked the effects of noradrenaline; the effect of noradrenaline (0.3 mumol/l) was abolished by the alpha 2-adrenoceptor antagonist idazoxan (0.5 mumol/l), but not by the alpha 1-adrenoceptor antagonist prazosin (1 mumol/l). It is concluded that release-inhibiting adrenoceptors of the alpha 2-subtype exist on 5-hydroxytryptamine terminals innervating the cerebral cortex in human and guinea-pig brain.

Adrenergic alpha-Agonists↗

Role of the posterior capsule in the aqueous-vitreous barrier in aphakic and pseudophakic eyes.

Clinical observations have shown that an intact posterior capsule between aqueous and vitreous may function as a barrier to low and high molecular weight substances, e.g., prostaglandins or the angiogenic factor. To determine if this protective barrier breaks down after posterior capsulotomy, we examined the distribution of fluorescein in human eyes after intracapsular cataract extraction (ICCE), extracapsular cataract extraction (ECCE) and intraocular lens (IOL) implantation with capsulotomy, and ECCE and IOL implantation without capsulotomy in 12 patients each. After ICCE and after ECCE and IOL implantation with capsulotomy, diffusion of fluorescein into the vitreous showed similar values. These values were significantly higher than those obtained in patients after ECCE or ECCE and IOL implantation without capsulotomy. This leads us to believe that an intact posterior capsule prevents the diffusion of soluble substances.

Aphakia↗