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Biomedical subjects

J G Worst

Publications and source records attributed to J G Worst.

At least 19 recordsLinked to original sources
PubMed1992

(An)aerobic bacteria found in secondary-cataract material. A SEM/TEM study.

Twenty four patients, who had marked reduction of vision due to secondary-cataract developed after an ECCE, were treated by surgical cleaning of the posterior lens capsule. During this procedure globular secondary-cataract material was removed and collected for morphological examination by SEM and TEM. Fragments of various sizes and shapes, including some with a 'golf ball' structure, were seen; these closely resembled particles frequently found in cataractous lenses. In addition, in 18 patients micro-organisms were found: rod-shaped bacteria, cocci, and in 2 cases yeasts. These findings were the more remarkable because these were clinically quiet eyes with no signs of intra-ocular inflammation and cultures have been persistently negative. We imagine that these bacteria must have entered the eye during the cataract extraction and have settled there without causing an infection.

Bacteria, Aerobic↗
PubMed1992

Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique. Part 1: Morgagni cataract.

Lens tissue from a Morgagni cataract was examined by SEM and TEM. For SEM, after prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO4 non-coating (TAO) technique, and for TEM, after prefixation with glutaraldehyde, postfixation with OsO4/K4Fe(CN)6 and poststaining with uranyl acetate/lead citrate. The TAO technique seems to be a particularly suitable postfixation method for the SEM investigation of cataract tissue because of the presence of the protein structures present. The cortical region showed areas of radially, instead of concentrically, arranged lens fibres, degenerated lens fibres with holes (vacuoles), broken ball and socket connections between the lens fibres, and oval or spherical structures varying in size from 0.5-20 microns, the largest resembling a golfball, arising from the cytoplasm of degenerating lens fibres. The smallest, 0.2-0.5 microns, appear to have been expelled from the furrowed lens epithelium.

Cataract↗
PubMed1992

Study of the substructure of the Morgagni and Brunescens cataract with the TAO non-coating technique. Part 2: Brunescens cataract.

Lens tissue from a Brunescens cataract was prepared for SEM study by prefixation with glutaraldehyde and postfixation with the tannic acid/arginine/OsO4 combination; for TEM study the material was prefixed with glutaraldehyde, postfixed with OsO4/K4Fe(CN)6 and poststained with uranyl acetate/lead citrate. At low magnification, in contrast to the Morgagni cataract, no difference could be seen between the lens fibres in the cortical and nuclear areas. Morphologically, the destruction of the ball and socket system and the development of holes and spherical structures was striking. The latter appeared to have a thin coating and, after fracture, were either empty or showed remnants of material resembling membranes. In sections of the cataractous material, larger vacuoles containing smaller spheres were indistinctly visible.

Cataract↗
PubMed1992

Comparative anatomy of the vitreous body in rhesus monkeys and man.

In the isolated unfixed vitreous body a structural organization can be visualized by slitlamp microscopy or by an ink-injection technique. We discuss the observations on human and rhesus monkey (Macaca mulatta) vitreous bodies using the ink-injection technique. Advantages and disadvantages of this method compared with slitlamp microscopy are described. Eventual functional implications of vitreal organization are mentioned briefly.

Animals↗
PubMed1991

Cell-ingrowth in a silicone plombe. Interactions between biomaterial and scleral tissue after 8 years in situ: a SEM and TEM investigation.

A male patients (42 years) who had been treated for retinal detachment by the implantation of a silicone plombe into the sclera, returned to the clinic 8 years after implantation because of inflammation of the tissue and partial protrusion from the sclera. After removal of the plombe this was processed for TEM and SEM and examination of the plombe material after 8 years in situ could be carried out in order to get information about the cell-biomaterial interface. A large proportion of the silicone pores was filled with cellular material, including macrophages, giant cells and erythrocytes thus indicating a foreign body granuloma. The external surface of the pores showed a granular osmiophilic dense amorphous layer including extracellular debris. Engulfing of silicone particles by macrophages and the evidence of long-term tissue response suggest partial biodegradation of the silicone and certainly not complete inertness as was formerly claimed.

Adult↗
PubMed1991

Morphological aspects of human lens capsules. A comparative LM, SEM and TEM examination.

Lens capsules of patients of advanced age, obtained after extracapsular cataract surgery, were carefully prepared for a combined LM, TEM and SEM investigation, after preliminary washing and mounting onto a holder in a buffer solution. After pre-fixation with GA, samples were postfixed for LM/TEM and OsO4/K4Fe)CN)6 and stained with toluidine-blue/basic fuchsin for LM and with uranyl acetate/lead citrate for TEM; for SEM the GA-pre-fixed samples were post-fixed by the Tannin Arginine-OsO4 non-coating technique. At LM-level discrimination between healthy and degenerating cells was possible after toluidine staining. At SEM-level protrusion of the cell nucleus and fibrillation and blebbing of the cell membrane as the result of capsular degeneration could be observed with the TAO-method. At TEM-level protrusion of the cell nucleus, degeneration of the cytoplasm, ballooning of the mitochondria, the presence of microfilaments and the occurrence of vacuoles were visible as the result of capsular degeneration on cataract formation.

Cataract Extraction↗
PubMed1991

A combined scanning and transmission electronmicroscopic investigation of human (secondary) cataract material.

Cataract lenses from patients of advanced age were processed for SEM by standard pre-fixation followed by treatment by the Tannin-Arginine-Osmium-tetroxide (TAO) method and critical point drying, and for TEM by standard pre-fixation followed by vibratomation, standard post-fixation, ultramicrotome sectioning and staining with uranyl acetate/lead citrate. Secondary cataract material was brought onto a Millipore filter, fixed by standard methods, dried in air and sputter-coated with Au. Both SEM and TEM images revealed degeneration processes in lensfibre material, such as swelling of the lensfibre, protrusion of the cytoplasm, fibrillation of the cell membrane, loss of the nucleus, spherical bodies of various sizes between 0.5-1.5 microns, sometimes surrounded by a (double) membrane with different contrast but without cellular evidence, and small and large vacuoles partly filled with granular material both in and at the periphery of the lensfibre-body. The secondary cataract material on the Millipore filter revealed erythrocytes and more or less spherical bodies with high contrast, measuring between 0.5-1.5 microns, often referred to as Elschnig's pearls, besides non-definable organic material. The SEM and TEM micrographs of the cataract lens material strongly suggest that the spherical bodies with sizes of approximately 0.5-1.5 micrometer and high contrast without cellular evidence, are similar to the more or less spherical bodies found in the secondary cataract material on the filter, referred to as Elschnig's pearls.

Cataract↗
PubMed1990

Refractive surgery for high myopia. The Worst-Fechner biconcave iris claw lens.

Surgical correction of high myopia is indicated in a limited number of cases. Techniques include (epi)keratophakia, keratomileusis and implantation of a negative-power IOL. The iris claw lens, fixed to the midperiphery of the iris, has proved its safety in aphakic eyes. The model has been adapted by giving it a vault in order to make it suitable for implantation in high myopic phakic eyes. The implantation technique and short-term results of patients operated by Worst are presented.

Adult↗
PubMed1990

Morphology of donor lens-capsule material studied by SEM.

The lens capsule of a 70-year-old male donor with a cataractous lens was carefully prepared for SEM by first washing the capsule with buffer solution to remove lens-fibres and subsequently attaching it to silicon rubber. During the fixation and drying stages of the preparation procedure the capsule stayed attached to the rubber substratum. In the equatorial zone germinating cells were found with knob-shaped microvilli, closely connected to lens-fibres. Large units of pathological capsule epithelial cells were found, only slightly inter connected by a few pseudopodia. In addition, single pathological epithelial cells with pseudopodia, arranged on top of the cell in a rosette-like configuration, were found at certain locations. Both types are probably related to the original lens-cataract.

Aged↗
PubMed1990

Reaction of the rabbit corneal endothelium to nylon sutures. A SEM study.

Nylon and stainless steel sutures separately placed deeply into rabbit corneas by splitting the stroma for a few millimeters, without closing sutures, remained in the cornea for two, four and six weeks respectively. In contrast to the stainless steel sutures an extensive tissue reaction could be observed clinically around the nylon sutures within a few days and was still present after 4-6 weeks. On the endothelial side, covering of the nylon with fibroblast cells took place very slowly, this in contrast with stainless steel. Irritation of the tissue and an oedematous appearance of the endothelium around the nylon suture was the result. At first a kind of collagen network, often mixed with inflammatory cells, was deposited on the nylon material before fibroblast cells could grow in. Covering of the stainless steel started quite soon after implantation, without preliminary deposition of collagen material. The reason for this phenomenon must be sought in the high free surface energy of the stainless steel, which attracts cells, in contrast to nylon which has a very low free surface energy.

Animals↗
PubMed1990

Secondary cataract material collected with a glass cannula. A SEM study.

Secondary cataract material from three patients, collected with a glass cannula approx. 18, 24 and 30 months respectively after operation, was prepared for SEM examination. For the soft samples this was done by filtration through a millipore filter followed by fixation and drying. The more solid material was suspended in a fixation solution, followed by centrifuging, suspension in 70% ethanol and drying on a specimen-holder. The short residence samples (18 months) showed mainly erythrocytes, some (inflammatory) cells and degenerated lens-fibre material. Most of the more solid material, which was collected more than 20 months after operation, showed fragments of (regenerated) capsule epithelium and pieces of solid lens-fibre material with fragments of capsule epithelium attached.

Cataract↗
PubMed1990

The Gonioseton, a surgical treatment for chronic glaucoma.

A new and simple technique for glaucoma filtering surgery is presented. It is based on the introduction of a stainless steel microspiral or gonioseton into a goniopuncture by way of an ab interno procedure, minimising surgical trauma to the filtration area. Preliminary results are presented.

Adult↗
PubMed1990

Implant surgery. Something old and something new.

A description of the author's (J.W.) technique for ICCE using a 'single-handed' freon cryo-extractor is given. Flieringa's ring is used for scleral support. Implantation is performed with an Iris Claw Lens. Stainless steel is used as suturing material.

Cataract Extraction↗
PubMed1990

The irrigating knife: an ultrasharp surgical blade with irrigating system.

We present an irrigating microsurgical knife for ocular surgery. Irrigation of balanced salt solution through the knife tip during sectioning removes hemorrhages continuously, allowing uninterrupted sectioning, without cauterization of bleeding vessels. The "zero degree" knife can be bent in any required position.

Acetates↗
PubMed1990

The van Andel transparent glass microsurgical cannula.

We present a disposable 21-gauge transparent glass cannula that provides optimal visual control of aspiration-irrigation procedures in cataract surgery. It is especially useful in iris coloboma repair.

Cataract Extraction↗
PubMed1989

Comparison of the reaction of the cornea to nylon and stainless steel sutures: an animal study.

In 11 rabbits a comparison was made between the reactions of the cornea to nylon and to stainless steel sutures, macroscopically and by means of scanning electron-microscopy (SEM). Macroscopically, the wounds sutured with steel thread showed much less reaction than the wounds sutured with nylon. Vascularization was never encountered in the wounds sutured with steel thread. SEM examination also showed clear differences, which became noticeable within a short time. Both on the suture and round the opening in the cornea extensive deposits of material are seen within a short time (1 week) in the case of nylon, in the case of stainless steel this reaction is much less marked. A few weeks later deposits also appear on the steel thread, but these have a different composition and contain no material suggestive of an inflammatory reaction.

Alloys↗