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Biomedical subjects

H L Kain

Publications and source records attributed to H L Kain.

15 recordsLinked to original sources
PubMed1992

[Pars plana lensectomy in pediatric cataract].

The pars plana approach to cataract extraction in the pediatric age has several advantages. We report of 9 eyes with congenital cataract and discuss the advantages of the pars plana technic. In all cases a single surgical approach was sufficient. There were no complications postoperatively which made either surgical or medical treatment necessary. Postoperatively aphakia was corrected with contact lenses. During pars plana-lensectomie the central part of the anterior and posterior capsule is removed and an anterior vitrectomie is performed. With this procedure secondary cataract formation could always be prevented.

Cataract↗
PubMed1992

[Model experiments of the outer blood-retinal barrier in vitro].

Because of the difficulty in conducting experiments on the outer blood-retinal barrier in vivo, we developed an in vitro model. Bovine retinal pigment epithelial cells were grown on semipermeable membranes, enabling separate manipulation of the apical and basal medium. As a parameter of barrier function, we measured the transepithelial resistance (TER). Barrier function was also tested with fluorescein. The transepithelial resistance increased under optimal culture conditions, in confluent cultures, by 200 omega and there was no fluorescein leakage. After exposure to trypsin in Ca/Mg-less medium or EDTA or after application of argon laser, we were able to induce a breakdown of the TER and fluorescein leakage. This happened immediately after laser exposure, 1 min after EDTA, and 4 min after trypsin application. We observed no morphological differences after breakdown of the barrier function on the intercellular connections compared to normal confluent cultures following EDTA or trypsin exposure. In all experiments there was a recovery of barrier function after returning the cells to control conditions. These first results demonstrate that our in vitro model is a sensitive method for investigating barrier function in retinal pigment epithelium in cell culture.

Animals↗
PubMed1991

[Simultaneous corneal transplantation in mucopolysaccharidosis].

We report the case of a 14 year old girl who obtained simultaneous penetrating keratoplasty for corneal opacity with functional loss as a consequence of a mucopolysaccharidosis typ Hurler/Scheie. Postoperatively, the host cornea displayed partial clearing. We discuss mechanisms possibly involved.

Adolescent↗
PubMed1991

[Uveitis after Yersinia enterocolitica infection].

Yersiniosis is a food-born infection. It may cause an acute enterocolitis and trigger an anterior uveitis. We report a case of bilateral panuveitis with chorioretinitis - thus with the involvement of anterior and posterior uvea. Because the agglutination titer against the Yersinia enterocolitica type 3 was increased, we consider it as the most probable etiology of the panuveitis. A serological test for Yersinia should be done in patients with uveitis, who consume food from various sources e.g. tourists or with diarrhea in anamnesis.

Adult↗
PubMed1991

[Bilateral chorioretinitis after infection with Yersinia enterocolitica].

We report a case of severe, bilateral panuveitis with disseminated chorioretinis. With systemic steroid therapy the inflammation resolved within 4 weeks, resulting in chorioretinal scarring. Because the agglutination titer against Yersinia enterocolitica type 3 was increased to 6 times over normal, we consider Yersinia to be the most probable cause of the panuveitis. Concomitantly, serology revealed evidence for recent infection with mumps and shigella. Both can cause anterior uveitis. Therefore, we cannot exclude interactions, which may influence the clinical picture. After reviewing the literature we describe for the first time a case of chorioretinits and panuveitis associated with infection by Yersinia.

Adult↗
PubMed1991

[Experimental studies of proliferative vitreoretinopathy].

A new experimental rabbit model was developed to investigate vitreoretinal proliferation (PVR). PVR was initiated by injection of zymosan A from Saccharomyces cerevisiae into the vitreous. The experiments were performed in two groups. In group A zymosan was injected into the normal vitreous; in group B zymosan was injected after the vitreous body had been degraded by the previous injection of hyaluronidase. In group A only moderate phagozytotic activity was found up to the 5 h day. However, in group B excessive invasion of macrophages was observed within 20 h and phagozytotic activity increased markedly. This was confirmed by an increase of enzymatic activity of beta-n-acetyl-glucoseaminidase in the anterior chamber and in the vitreous space. Transmission electron microscopy revealed characteristic morphology in zymosan A, which can apparently only be digested very slowly in the phagocytes. Therefore, macrophages could be traced during their transformation into fibroblastlike cells forming the vitreoretinal membranes.

Acetylglucosaminidase↗
PubMed1990

[A new concept for keratoprosthesis].

Although keratoprosthesis (after Strampelli and Cardona) is successful in selected cases, it remains doubtful whether the apparent problems of these procedures can be solved. The Cardona-Strampelli concept was therefore abandoned; a new design was evolved and new alloplastic materials were used--silicone for the optical zone and carbon fibers for the haptic part of the prosthesis. The interaction of living tissue with these alloplastic materials was investigated in tissue-culture experiments and in vivo, and indicated that the materials had excellent properties for prosthetic purposes. Stable anchorage of the implants was assured by the strong adhesion of the fibroplasts to the carbon fibers. In more than a year of observation no granulomatous reaction was observed. In animal experiments, the special design of the prosthesis-tissue interface prevented epithelial downgrowth, one of the major problems in keratoprosthesis. Moreover, a fluid-tight interaction of the alloplastic material and the tissue was achieved.

Animals↗
PubMed1990

[Vitreous body surgery].

A variety of pathological changes of the vitreous endanger the function of the retina and are therefore reason for removement of the vitreous body. The most important technique is the pars plana vitrectomy, which allows to perform the surgical manoeuvre on the stabilized eye. Different indications for vitreoretinal surgery are discussed, as well as materials, which are used for replacement of the vitreous. When long standing replacement of the vitreous is necessary in complicated cases, silicon oil is the most important material.

Emergencies↗
PubMed1986

Early vitreous changes in experimental proliferative vitreoretinopathy.

Proton magnetic resonance imaging (MRI) was employed to obtain information on early vitreal changes preceding ophthalmoscopically visible proliferative vitreoretinopathy. Rabbits were injected close to the posterior pole with a suspension of 250 000 cultured homologous fibroblasts. The MRI was carried out using a 1.4-tesla (T) superconducting imager (at a proton frequency of 61.4 MHz). The images were obtained over a span of six days, prior to any detection of proliferative vitreoretinopathy with ophthalmoscopy. As early as two days after injection, an area of increased spin-spin relaxation time (T2) corresponding to the vitreal injection site became visible. The MRI observations paralleled in vitro changes in proton relaxation times (T1 [spin-lattice relaxation time] and T2) after addition of beta-N-acetylglucosaminidase to the vitreous. Our data suggest that hyaluronate disruption due to the activity of fibroblastic enzymes may result in fibroblast dispersion and movement in the vitreous and that MRI can provide early signs of vitreal changes that lead to retinal detachment.

Animals↗
PubMed1984

A new model for examining chorioretinal adhesion experimentally.

A method for examining retinal adhesion in vitro is described. Retinal detachment is produced experimentally by injecting Ringer's solution from a micropipette into the retinal pigment epithelial interface. The resulting detachment is a round blister, demonstrating equal retinal adhesion and elasticity in all directions under physiologic conditions. Measurement of hydrostatic pressure in the experimental detachment allowed postmortem changes to be followed up. Normal adhesion was found up to ten minutes after enucleation. Reduced adhesion was evident more than 15 minutes following enucleation; after 25 minutes, adhesion was so poor that blisters could no longer be formed. The loss of retinal adhesion seems to result from the exhaustion of metabolic substrates in the isolated tissue. Local alterations in adhesion, as after photocoagulation, can be detected as characteristic changes in the shape of experimental detachment and indicates enhanced, diminished, or unchanged adhesion. The present method, thus, defines normal conditions, identifies degenerative and artifactual changes, and permits localized changes in adhesion to be differentiated.

Animals↗
PubMed1984

Chorioretinal adhesion after argon laser photocoagulation.

A technique for examining chorioretinal adhesion in vitro investigated the strength of the adhesion resulting from photocoagulation. The adhesion was reduced only within the first days following photocoagulation, returned to normal by the third day and became enhanced at the fourth day, much earlier than previously supposed. Optimal adhesion and enhanced adhesion resulted only when the coagulation intensities used were sufficient to produce clearly visible lesions that became pigmented subsequently; second, best adhesion was produced with spot-diameters of 200 microns and greater; third, even under optimal coagulation conditions, single barriers were not able to resist extensive forcing, even when the exposures were confluent; fourth, only double barriers, consisting of two rows of exposures, were consistently able to withstand prolonged forcing. The best treatment for retinal tears is a double barrier of large, high-intensity coagulation spots, which affords enhanced adhesion after four days.

Animals↗
PubMed1983

Retinal adhesion.

The development of retinal adhesion after coagulation has been investigated by the use of an experimental model of detachment in which fluid is injected into the retinal pigment interface. This adhesion, which varied from day to day in a predictable manner was low on the third day. The possible reasons for this are discussed.

Adhesiveness↗