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Biomedical subjects

W K Waller

Publications and source records attributed to W K Waller.

13 recordsLinked to original sources
PubMed1978

[The influence of cryoprotective solutions on the ultrastructure of rabbit corneal endothelium (author's transl)].

A series of rabbit corneae was preserved at -196 degrees C in liquid nitrogen using five different cryoprotective solutions: (1) 5% dextran T 40, (2) 10% polyvinylpyrrolidone, (3) 5% dextran T 40 + 10% polyvinylpyrrolidone + dimethyl sulfoxide, (4) 25% rabbit albumin + 10% polyvinylpyrrolidone, (5) 25% rabbit albumin + dimethyl sulfoxide. After thawing the corneae, the influence of the different cryoprotective solutions on the ultrastructure of corneal endothelium was evaluated and compared with fresh corneae. The results were as follows: (1) Using 5% dextran T 40 or 10% polyvinylpyrrolidone or 25% rabbit albumin as cryoprotective solutions marked intracellular damage. (2) Adding dimethyl sulfoxide to the solutions cryopreservation appeared to be more successful at the cellular basis, despite the freezing and thawing procedure mediated moderate intracellular changes. Cryopreservation including dimethyl sulfoxide renders better conditions for successful corneal grafting in the light of ultrastructural aspects.

Albumins↗
PubMed1978

The vascular basis of the positional influence of the intraocular pressure.

By measuring intraocular pressure in different body positions from 60 degrees semiupright to 30 degrees head down, a nonlinear relationship between IOP increase and body position was confirmed. IOP postural response in individual subjects was roughly correlated to ophthalmic arterial pressure and to the episcleral venous pressure postural response. In one series of subjects, the episcleral venous pressure increments due to posture wa; parallel to the applanation-indentation disparity in the same individual eyes. Differential tonometry with applanation or indentation procedures under blind conditions gave significantly low indentation readings. It is concluded that IOP postural response depends on arterial and venous vascular changes when subjects move from an erect to a horizontal body position. Blood expulsion from the choroid by indentation tonometry might be the reason that this tonometric procedure does not measure IOP changes based on vascular changes.

Adult↗
PubMed1978

[Vital staining of the endothelium of preserved corneae with Trypan Blue (author's transl)].

As a development of Capella's and Kaufman's procedure we examined on four series each with 20 pig corneae the four antifreezing solutions described by the authors singly with regard to their protective effect against freezing. After thawing at +60 degrees within 50 seconds and rehydration with 25% Serum albumin (in the fourth series 10 corneae were rehydrated with polyvinylpyrrolidone) the endothelium was stained with Trypan blue. Microphotographs were made of the endothelial surface, stained nuclei counted and the results were analysed statistically and compared one with other. Hence we could show that with increasing concentration of the antifreeze solution the vitality of the cornea increases.

Animals↗
PubMed1977

Cytochemical localiztion of nucleoside diphosphatase and thiamine pyrophosphatase activities in the rabbit corneal endothelium.

Localization of NDPase and TPPase activities in the rabbit corneal endothelium was investigated by cytochemical methods. After incubation at both pH 7.0 and 8.0, the NDPase activity was detected in cisternae of ER, nuclear envelope, and Golgi saccules, while the TPPase activity was demonstrated only in Golgi saccules. The reaction products of both enzymes were decreased when incubated at pH 8.0. The NDPase activity was inhibited by uranyl nitrate but not by sodium fluoride, while the TPPase was inhibited by fluoride but not by uranium.

Animals↗
PubMed1976

Histochemical evaluation of enzymes in the rabbit corneal endothelium after short-term storage.

Isolated rabbit corneae were stored at a temperature of 4 degrees C in McCoy's 5a medium (modified) containing 5% dextran T 40 and gentamycin sulphate (250 mug/ml) for a varied number of days. The endothelium of the corneae was examined by light- and electron-microscopic histochemical methods for ATPase, TPPase, and SDH. The activity of each enzyme in the endothelia, stored for 6 days, was found to resemble the enzyme activities in the fresh corneal endothelium. By 8 days, the SDH activity was lowered and specific staining for ATPase and TPPase was decreased. In the 12 day-stored endothelium, the SDH and TPPase activities could not be detected. From these results, it was gathered that the isolated cornea stored in the medium for 6 days may be used in keratoplasty.

Adenosine Triphosphatases↗
PubMed1976

[Intraocular pressure measurements on soft contact lenses (author's transl)].

The pneumotonograph was evaluated for its capability to record and measure intraocular pressure through soft contact lenses. In a series of patients with chronic corneal diseases treated with soft contact lenses, good pressure and intraocular pulsations were recorded both with and without the soft lenses. Areas of scarred cornea give incorrect values, whereas areas of corneal edema give values similar to those obtained in the presence of a soft lens and are believed to reflect accurate and reliable pressure readings. In normal eyes, it has been found that the presence of a plain soft lens does not modify the accuracy of pressure measurement. High values do occur, however, when the refraction of the lens exceeds eight diopters.

Contact Lenses, Hydrophilic↗
PubMed1976

Concomitant Subdural and Preretinal hemorrhage.

A case report is presented of a patient with a chronic subdural hematoma, who only once had a short episode of central nervous signs. The outstanding symptom was a seemingly spontaneous introcular hemorrhage, ipsilateral to the subdural hematoma. The mechanism of the ocular manifestation is discussed.

Adult↗
PubMed1976

[Light and electron microscopic studies on short-term preserved corneae (author's transl)].

Rabbit corneae were stored at a temperature of +4 degrees C in the following media: 1. 5% Dextran T40, 2. McCoy's Medium 5a (modified), 3. Dextran T 40+McCoy's 5a Medium + gentamicin sulphate (250 mug/ml). The endothelia of the corneae were examined by light and electron microscopy after preservation for a varied number of days. The structure of the endothelia, stored for 1, 6, 12, 18 days, was compared to fresh corneal endothelial cells. The results indicate that corneae preserved in Dextran 5% T40 + McCoy's 5a Medium + gentamicin sulphate might be equivalent to fresh corneal tissue in keratoplasties.

Animals↗
PubMed1976

Uptake of horseradish peroxidase (HRP) by the endothelium of the short-term stored rabbit cornea.

In vitro study of the uptake of horseradish peroxidase (HRP) by the corneal endothelium was carried out on rabbit corneae which were stored in a preserving medium for various periods. The stored corneae were incubated in HRP solution with or without adenosine triphosphate (ATP). The number of pinocytotic vesicles decreased as the storage time was prolonged. Addition of ATP to the HRP solution led to an increase in the pinocytotic vesicles in all storage periods. The pinocytosis in the 12-day stored corneal endothelium was only observed when the tissue was incubated in an HRP solution containing ATP. From these results, it was concluded that the viability of the stored corneae can be evaluated with uptake of HRP by the endothelial cell, and that the addition of ATP leads to an enhancement of pinocytotic activity in the endothelial cell.

Adenosine Triphosphate↗
PubMed1975

Electron microscopic localization of carbonic anhydrase (CA) activity in rabbit cornea.

The localization of CA activity in the rabbit cornea was investigated using a modified Hansson's method. The reaction products indicating CA activity was observed in the lateral membrane of endothelial cell, but not in the apical membrane. In cytoplasm, Golgi complex, and mitochondria of the endothelial cells no specific reaction product could be found. In epithelium, stroma, and Descemet's membrane, no reaction product was seen. The specific staining was inhibited in the control group which was treated with 10(-4)M sodium acetazolamide.

Animals↗
PubMed1975

Goldmann applanation versus hand-applanation and .schiötz indentation tonometry.

For evaluation of hand-applanation tonometry comparative measurements of intraocular pressure have been carried out using the Goldmann applanation tonometer, the Draeger and Perkins hand-applanation tonometers and the Schiötz indentation tonometer. A series of 52 eyes has been tested. The statistical analysis was based on the Goldmann tonometry as a reference system. The hand-applanation tonometers were found to be in satisfactory agreement with the Goldmann tonometer, whereas the Schiötz tonometer gave significantly low values in the pressure range considered.

Humans↗