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Biomedical subjects

J F Worst

Publications and source records attributed to J F Worst.

9 recordsLinked to original sources
PubMed1986

A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

Animals↗
PubMed1986

A SEM-study of a keratoconus and an artificially aged human cornea.

The substructure of both the epithelial and endothelial surfaces of a keratoconus and an artificially aged cornea was compared with that of a healthy cornea by investigating them with a scanning electron microscope. From the depressions around the protruding centre of the epithelial surface of the keratoconus cornea, and from the whole epithelial surface of the artificially aged cornea, cells detached themselves, assuming a more or less rounded shape. The endothelial surface of both the keratoconus and the aged cornea showed areas of cells with an almost completely disintegrated cell membrane, exposing the cell contents. On the endothelial surface of the keratoconus cells were found with a missing cell-nucleus and a perforated cell membrane, due to a 'Kammerwasser Einbruch' effect.

Aging↗
PubMed1986

Degradation of polypropylene in the human eye: a SEM-study.

A polypropylene surgical suture, which had served as fixation suture for an IOL for a period of 6.5 years, was removed from the eye of a Dutch patient because it had broken at one end and thus formed a potential risk for a corneal touch syndrome. After careful rinsing in 50% ethanol, to remove adhering debris, it was prepared for SEM. A virgin piece of polypropylene material from a surgical package underwent the same preparative procedure. The fixation suture showed cracks perpendicular to the longitudinal axis of the suture; part of the surface layer was nearly detached or completely missing; while the diameter of the suture was decreased towards both ends by over 50% in comparison with the original diameter. The exposed subsurface layer showed a fibrillar structure. The degradation phenomena are considered to be caused by the enzymatic action of tissue-fluids. Virgin material did not show any of the phenomena observed on the fixation suture under consideration.

Eye↗
PubMedDate not supplied

Fungal growth on soft contact lenses: a SEM-study.

Three soft contact lenses of the HEMA type, discarded because of irritation of the cornea, were processed for and subsequently examined with the SEM, A large portion of the convex surface was covered with globular deposits of fungal spores. Cross-fractures of lenses showed penetration of the fungi into the matrix material of the lenses. The concave surface of the contact lenses showed at two points imprints of the epithelial cells of the cornea in the deposited material on that side of the lenses.

Contact Lenses, Hydrophilic↗
PubMedDate not supplied

The keratoconus epithelium studied by SEM.

A keratoconus removed from an 18-year-old male was processed for SEM and examined with special attention for the epithelial surface. A broad degenerative band was found running in the vertical meridian, showing areas devoid of, or with only partially attached, epithelial cells, and also areas with abnormal cells either, with a defective cell membrane and without cell contents or with an intact cell membrane but without a cell nucleus. Stereoscopic images of these defective cells show that cell degeneration is sometimes found several cell layers deep into the epithelium.

Adolescent↗
PubMedDate not supplied

The cisternal anatomy of the vitreous body.

The vitreous body of a fresh human eye removed post-mortem was suspended in water after stripping off the corneo-scleral coat, the choroid and the retina. Coloured ink was injected into the vitreous specimen from different points. Individual spaces (cisterns), transitions between cisterns and specialized structures like the bursa premacularis and the canal of Cloquet became visible when partial filling had taken place. SEM-examination of the individual cisternal walls of the bursa premacularis area showed networks of different density and texture and a considerable variation in the length of the individual fibres, some of which extended from the ciliary body (Retzius bundles) to the rim of the Bursa premacularis.

Humans↗
PubMedDate not supplied

A morphological description of human cataractous lenses by SEM.

Human cataractous lenses from patients of advanced age (101 & 85 year) were investigated by SEM. Various aspects of the cataract morphology could be observed. Even when the overall shape of the lens fibres had remained unchanged (although the typical ball and socket interconnections were barely visible) the homogeneous fibre content had changed into fibrillar and/or granular material, or the lens fibres had been (partly) hollowed out. Where there was shrinkage of the originally hexagonally-shaped lens fibres to a more or less rounded form with a wrinkled surface, the contents had changed into granular material with low density. Both granular and fibrillar material could account for a substantial increase in light scattering, resulting in a considerable decrease in vision through the lens.

Aged↗
PubMedDate not supplied

Descriptive anatomy of the ageing process of the human cornea as visualized by SEM.

Two corneas from elderly patients (87 & 95 years) were studied by SEM and the results compared with in-vitro aged corneas and a keratoconus. The detachment of epithelial cells as part of a cell renewal process leads to loss of epithelium and exposure of Bowman's membrane. The degenerative process in the endothelium leads to porosity and loss of the endothelial cell membrane and finally to (partial) loss of the endothelial cell layer. The start of such a degenerative process is marked by the formation of liquid-filled blebs. The balance of degeneration versus regeneration is clearly biased in favour of the degenerative process, because the cells are not able to produce sufficient collagenous material to cover the denuded areas.

Aged↗