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Biomedical subjects

H Laqua

Publications and source records attributed to H Laqua.

At least 91 records · Page 5Linked to original sources

[Clinical heterogeneity of non-Hodgkin's lymphoma of the eye with extraocular manifestations].

Primary, ocular Non-Hodgkin lymphoma is a multicentric disease. The prognosis is mostly determined by involvement of the central nervous system and/or visceral organs. Since ocular symptoms often precede accompanying manifestations and since the eye is easily accessible to diagnostic measures, the ophthalmological diagnosis is essential for early detection and treatment of this complex disease, which has a poor prognosis. To illustrate the extraordinary heterogeneity of the clinical symptoms, four case reports have been selected which demonstrate various ocular symptoms and extraocular localizations. The ophthalmological variability ranges from typical uveitis to retinitis and vasculitis with varying symptoms during the progression of the disease. Completely different extraocular features were induced by long-standing, local infiltrates within basal ganglia, a diffuse infiltration of the brain leading to an acute increase in intracranial pressure, a peripheral tumour within the spinal channel or massive infiltrates of liver, lung and kidneys. Lack of pathognomonic features, high clinical variability and the limited value of imaging techniques and histopathological measures often lead to serious delays in diagnosis.

Aged↗

The photoreceptor cells and retinal pigment epithelium of normal and diseased human retinas express different glycoconjugates.

The photoreceptor cells and retinal pigment epithelium (RPE) represent a highly differentiated functional unit that may be disrupted in a variety of retinal diseases. We studied the localization and distribution of carbohydrate residues in normal and pathologically altered human retinas using lectin histochemical techniques. Paraffin-embedded tissue sections were investigated for binding sites with six lectins: concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA I), peanut agglutinin (PNA), soybean agglutinin (SBA), and Ulex europaeus agglutinin (UEA I). Lectin binding to both the photoreceptor segments and the RPE was observed in the normal retina with Con A, WGA, RCA I, and PNA, particularly to the distal outer segments and to the apical portion of RPE cells. Disturbance of the photoreceptor-RPE cell complex occurred in eyes with damaged outer retinal layers and those with retinal detachment. Photoreceptor cells with a varying degree of inner and outer segment degeneration revealed an overall decrease in lectin-binding sites as well as alterations in their cellular topography. Reactive and proliferating RPE, however, showed a markedly increased reaction intensity for Con A, WGA, RCA I, and PNA as well as additional binding sites for SBA in macrophage-like variants. The data are taken as evidence that in the normal retina, a characteristic location and distribution of lectin-binding sites as well as correspondences in certain cellular glycoproteins of both photoreceptor cells and the RPE are indicative of structural and functional integrity. Disturbance of the photoreceptor-RPE cell complex is accompanied by changes in the expression of lectin-binding sites on both cell types.

Aged↗

Retinal lesions experimentally produced by intravitreal ultrasound.

Currently, vitreous surgical techniques combined with phakoemulsification are an established procedure for the removal of luxated natural lenses or dislocated lenticular material. This has proven to be a safe procedure, but occasionally retinal lesions have been inadvertently created. We describe the ophthalmoscopic and morphologic features of ultrasonically induced retinal lesions in rabbit eyes using a similar technique. The retina was treated directly using a conventional ultrasound tip for pars plana lensectomy (Fragmatome). Ophthalmoscopically slight lesions corresponded to an area of retinal whitening. More severe lesions showed a destruction of the inner retina and created a retinal break. Extensive effects also involved the choroid and led to a retinal defect with rupture of choroidal vessels and heavy bleeding into the vitreous cavity. Histologic evaluation showed that the acoustic energy primarily led to damage of the outer retina, later involving the inner retina and the choroid as well.

Animals↗

Lectin binding pattern in human retinal pigment epithelium.

A comparative lectin histochemical study of human retinal pigment epithelium (RPE) was performed to investigate the lectin binding pattern of normal, reactive and proliferating RPE. Normal RPE with attached sensory retina was found to bind the lectins Con A, WGA, PNA and RCA I. Reactive and proliferating RPE in retinal detachment and in photocoagulation scars revealed the same lectin binding pattern although its cellular topography changed. RPE-macrophages showed an additional reaction with SBA. In periretinal membranes of human PVR the typical lectin binding pattern of Con A, WGA, PNA and RCA I was found in pigmented and in a subpopulation of non-pigmented cells, suggesting that these lectin-positive elements were of RPE-origin. Additionally, single pigmented cells positive for SBA were found indicating macrophage differentiation. Thus lectin histochemistry provides a tool for cytochemical identification of RPE and its morphologic variants by revealing a specific combination of sugar-binding sites.

Binding Sites↗

Acute onset of rubeosis iridis after diabetic vitrectomy can indicate peripheral traction retinal detachment.

Acute onset or exacerbation of rubeosis iridis associated with peripheral retinal detachment after vitrectomy represents a rare but serious complication of advanced diabetic retinopathy that indicates a poor prognosis. The clinical features, surgical procedures, and anatomical and functional results for a series of 13 eyes presenting with this complication are reported. In addition to rubeosis iridis and peripheral retinal detachment, anterior hyaloidal fibrovascular proliferation (APH) was also present in 10 eyes. All eyes had undergone one or more previous vitrectomies for diabetic complications such as nonclearing vitreous hemorrhage and traction retinal detachment. Treatment modalities for iris neovascularization and peripheral retinal detachment included reattachment procedures with an encircling band, peripheral membrane peeling, and, if necessary, peripheral retinectomy. Peripheral coagulation therapy was performed in all eyes. Eight eyes received an intraocular silicone-oil tamponade. Early results (4 weeks post-surgery) showed regression or stabilization of rubeosis iridis in all eyes. Later results (mean, 9 months post-surgery) revealed nine eyes with stabilized anterior ocular neovascularization and reattachment of the retina. Four eyes were anatomic failures due to recurrent rubeosis iridis/AHP or traction retinal detachment, and three of them also developed ocular hypotony. None of the eyes has thus far been lost as a result of neovascular glaucoma or painful phthisis. Ambulatory vision was retained in ten eyes, but function was limited to a low level as a result of the underlying ischemic disease. Immediate reattachment surgery in combination with anterior/peripheral coagulation therapy was shown to be an effective measure for controlling iris neovascular activity in eyes afflicted with acute anterior ocular neovascularization.

Acute Disease↗

The autosomal dominant familial exudative vitreoretinopathy locus maps on 11q and is closely linked to D11S533.

Autosomal dominant familial exudative vitreoretinopathy (adFEVR) is a hereditary disorder characterized by the incomplete vascularization of the peripheral retina. The primary biochemical defect in adFEVR is unknown. The adFEVR locus has tentatively been assigned to 11q by linkage studies. We report the results of an extended multipoint linkage analysis of two families with adFEVR by using five markers (INT2, D11S533, D11S527, D11S35, and CD3D) from 11q13-q23. Pairwise linkage data obtained in the two families were rather similar and hence have not provided evidence for genetic heterogeneity. The highest complied two-point lod score (3.67, at a recombination fraction of .07) was obtained for the disease locus versus D11S533. Multipoint analyses showed that the adFEVR locus maps most likely, with a maximum location score of over 20, between D11S533/D11S527 and D11S35, at recombination rates of .147 and .104, respectively. Close linkage without recombination (maximum lod score 11.26) has been found between D11S533 and D11S527.

Chromosome Mapping↗

Congenital grouped albinotic spots: a rare anomaly of the retinal pigment epithelium.

We describe the fundus findings of a 6-year-old girl with congenital grouped albinotic retinal pigment epithelial spots distributed over the fundus including the macular area. Apart from the fundus changes functional and electrophysiologic findings were normal, and the family history was uneventful. At follow-up 3 years later, no progression was noted.

Albinism, Ocular↗

[Removal of silicone oil in treatment of so-called emulsification glaucoma].

We investigated whether emulsification glaucoma after silicone oil implantation can be influenced positively by removal of the oil. In 16 of 264 patients successfully operated upon with purified silicone oil 5000 cps, we found a glaucoma refractory to medical therapy and probably caused by emulsification. We removed the silicone oil from these eyes and followed them up for a period of 6 months (12.5 +/- 7.3 months). In 12 of the 16 eyes, the intraocular pressures were normalized after silicone oil removal with or without antiglaucomatous therapy. Four eyes showed raised intraocular pressures in spite of silicone oil removal. These could, however, be largely explained by neovascularization or chronic inflammation with increasing anterior synechia formation. In eyes with possible emulsification glaucoma, early and thorough removal of the silicone oil is therefore recommended since this can result in normalization of intraocular pressures in a large percentage of cases.

Glaucoma↗

[The effect of cyclooxygenase inhibitors on the course of hereditary retinal dystrophy in RCS rats].

Daily administration of acetyl salicylic acid (ASA) and ibuprofen leads to an appreciable retardation in the process of retinal degeneration in the RCS rat which is dependent on the dosage given. The photoreceptor cell nuclei and inner segments are relatively well preserved in all regions of the retina. While the outer nuclear layer of 32 day old RCS rats is usually composed of only 3-4 rows, we found 8-9 nuclear rows exhibiting minimal pyknotic change in animals which had been treated with higher doses of ASA. These differences in layer thickness could be confirmed using morphometric analysis. The outer segments show evidence of degenerative change although they are in a clearly better condition than those found in untreated animals and in those animals treated at lower dose. Phagolysosomal structures which are not otherwise apparent in this strain of rat are detected only in the RPE cells of animals treated with higher dose. The animals treated with ibuprofen show essentially the same morphological changes although a corresponding effect in regard to the thickness of the outer nuclear layer was only achieved after a high dose. The determined dose for the optimal preservation (thickness) of the outer nuclear layer lies around 160 mg/kg body weight for acetyl salicylic acid and at 400 mg/kg body weight for ibuprofen.

Animals↗

[Peripheral retinal streaks. Linear depigmentation of the peripheral retinal pigment epithelium].

An unusual peripheral depigmented streak lesion of the retina is described in three patients. This depigmented line is located in the equatorial region running parallel to the ora serrata and seems to result from a focal reduction or loss of pigmentation in the retinal pigment epithelium. Similar lesions have been reported as a symptom of the presumed ocular histoplasmosis syndrome (POHS) called linear streaks of the equator. As we did not find any additional symptoms of POHS in our patients, the aetiology of this peripheral depigmented streaks remains unclear.

Aged↗

[Corneal Ascher ring. A ring-shaped stromal corneal opacity].

An unusual bilateral ring-shaped corneal opacity has been observed in two patients. Biomicroscopical characteristics are minute greyish dots which are distributed within the outer stromal layers forming an arcus lipoides-like circular band. Besides of a typical arcus senilis no other corneal anomalies can be found. Up to date only 4 patients with similar corneal opacities have been described. Etiology remains unclear and according to the author who has first described this symptom we propose to name this corneal anomaly "Ascher-Ringe".

Aged↗

[Fluorescein angiography findings after retinotomy and retinectomy].

Drainage-retinotomies and relaxing retinectomies are helpful techniques in extreme vitreoretinal surgery. They have become established as a surgical instrument, but their possible pathophysiologic effects on the retina, pigment epithelium and choroid have not been investigated as yet. 30 Patients with retinotomies or retinectomies after vitrectomy with silicone oil filling for advanced proliferative vitreoretinopathy were studied angiographically. Fluorescein angiographic findings revealed 1. a predominant effect of endophotocoagulation in the area of the retinotomy/retinectomy with occlusion of the choriocapillaris and hyperpigmentation and window effects of the retinal pigment epithelium, but sometimes there was a localized traction effect with retinal and choroidal folds, 2. that retinal perfusion is unaffected in untreated and coagulated areas without evidence for a breakdown of the blood-retina-barrier or retinal ischemia, 3. an intact blood-retinal-barrier in areas of uncovered retinal pigment epithelium, 4. no evidence for significant reproliferations in the areas of retinotomies and retinectomies, 5. choroidal neovascular membranes which may occur postoperatively at the retinotomy site probably as a complication for intraoperative injury of Bruch's membrane, 6. a cystoid macular edema, an optic atrophy, pigment-fallout, depigmented tracks and choroidal folds as unspecific findings post retinal detachment surgery. The angiographic data support the clinical impression, that retinotomies and retinectomies performed in otherwise untreatable cases cause no significant damage in the attached retina.

Drainage↗

[Retinal lesions after transvitreal use of ultrasound].

Removal of a dislocated natural lens into the vitreous cavity is now performed using vitreous surgery techniques combined with intravitreal phacoemulsification via the pars plana. In contrast to the earlier external surgical approach to luxated lenses, postoperative complications, particularly retinal detachment, are rare. However, retinal damage may occur when ultrasound is used at therapeutic intensities. We therefore examined ultrasound-induced retinal lesions produced in rabbit eyes by treating the retina directly with ultrasound using the type of tip conventionally used for pars plana lensectomy (Fragmatom). Histological evaluation showed that acoustic energy at low intensities led primarily to damage of photoreceptor cell outer and inner segments, which correlated with a discrete pigment reaction visible on ophthalmoscopy. More severe lesions were seen in destruction of the inner retina and resulted in retinal blanching or caused a small retinal break. High energy led to a full-thickness retinal defect with rupture of choroidal vessels and heavy bleeding into the vitreous cavity. Within these lesions the retinal pigment epithelium and Bruch's membrane were also disturbed. Our ophthalmoscopical and histological findings indicate that the mechanism of ultrasound-induced chorio-retinal lesions is not exclusively thermal in nature and differs from other coagulation modalities.

Animals↗

[Visual outcome after silicon oil surgery].

The question as to whether silicone oil is toxic to the retina has not been resolved to this day. We have attempted to find evidence of retinal toxicity by studying the development of visual acuity in eyes operated on with silicone oil. We selected these eyes from a cohort of about 500 that had attached retina, no glaucoma and no keratopathy. The average visual acuity increased continuously over 2 years if all extraretinal factors influencing visual acuity are excluded. Although in eyes from which silicone oil had been removed visual function developed better than in those in which it remained indefinitely, this could not be attributed to a toxic effect of silicone oil, since the difference was apparent even while eyes in both cohorts where still filled with oil. The difference is more probably a result of patient selection. In individual cases in which silicone oil was not removed for up to 8 years the visual acuity remained stable. An analysis of the patients with loss of vision despite attached retinas yielded causes that were essentially specific to the underlying disease. We found no clinical evidence suggestive of a toxic effect of silicone oil.

Follow-Up Studies↗

[Pars plana capsule resection for therapy of ocular hypotension syndrome caused by capsule shrinkage with ciliary body detachment].

A rare complication of extracapsular cataract extraction is hypotony due to capsular shrinkage, with consequent ciliary body detachment. A classic hypotony syndrome with progressive loss of visual acuity was observed in two patients, one with extracapsular aphakia and one with extracapsular pseudophakia. Each presented with a fibrotic, shrunken capsular bag and a secondary cataract. As the contraction forces appeared to derive predominantly from the periphery of a circumferentially fibrotic capsular bag, the lens capsule was operatively removed. A pars plana approach was used to access the equatorial capsular ring and visualize the ciliary body processes. The intraocular lens appeared to be stable and remained in situ. Postoperative elevation of intraocular pressure occurred, with improvement of hypotony symptoms, especially in the fundus. Visual acuity also improved, but was limited due to secondary cystoid edema.

Adult↗

[Secondary glaucoma after silicone oil surgery].

In spite of advances in surgical technique and the development of purified silicone oils, secondary glaucoma still develops in 10-20% of cases following silicone oil surgery. In the first part of this study it is shown by life-table analysis that factors such as early lens removal, inferior iridectomy, early silicone removal or the use of purified silicone oil have little or no influence on the development of glaucoma. In the second part an attempt is made to pinpoint possible causes of secondary glaucoma by re-examining all cases in which elevated intraocular pressure developed some time after silicone oil surgery. It was found that a multitude of factors (e.g., inflammation, angle-block, anterior peripheral synechiae and emulsification) were involved in the pathogenesis of temporary or persistent secondary glaucomas. In most cases pre-existing pathology was found to be responsible rather than the silicone oil itself. The majority of the cases in which the silicone oil caused secondary glaucoma by emulsification responded well to medication alone or removal of the silicone oil.

Aphakia↗

[Retinoschisis with a giant central outer layer retinal tear and concomitant detachment].

The authors report on 2 cases with a special form of senile retinoschisis with retinal detachment. In both cases, a typical retinoschisis was combined with a giant tear of the outer retinal layer and a sickle-shaped retinal detachment extending almost to the macula. In contrast to previously published cases, which were treated by a conventional scleral buckling procedure or vitrectomy with fluid air exchange, it was decided to demarcate the retinal detachment by argon laser photocoagulation. The authors consider this non-invasive procedure sufficiently safe and effective.

Female↗