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Biomedical subjects

B T Philipson

Publications and source records attributed to B T Philipson.

9 recordsLinked to original sources
PubMed1990

Intraocular levels of cefuroxime in uninflamed rabbit eyes.

Intraocular levels of cefuroxime following subconjunctival, intravitreal and combined intravitreal and intravenous administration were determined in uninflamed rabbit eyes. Intraocular levels of the antibiotic were assayed by a biological method. Penetration of cefuroxime into the vitreous following subconjunctival administration was poor. Subconjunctival administration produced higher levels of cefuroxime in the aqueous when compared to parenteral administration alone. Higher levels of cefuroxime were achieved both in the aqueous and in the vitreous after an intravitreal injection. Intravitreal injection of 100 and 1000 micrograms cefuroxime produced intravitreal levels close to the minimum inhibitory concentration (MIC) for most ocular pathogens up to 24 h after drug administration. Intravenous supplementation did neither enhance the intraocular levels nor did it delay the clearance of the intravitreally injected antibiotic. Mild histopathological changes were seen with equal frequency both in the control and the test eyes and are attributed to the sampling techniques. Electroretinography (ERG) showed no definite changes suggestive of retinal toxicity up to 55 days after intravitreal administration.

Animals↗
PubMed1990

Subcapsular zones of discontinuity in the human lens.

Zones of discontinuity parallel to the lens surface can be seen in the normal lens on slitlamp examination. These zones have been suggested to be surfaces at which the refractive index changes from one value to another. Normal lenses from tumor eyes have been examined by quantitative microradiography. The protein concentrations has been determined in thin sections from the anterior cortex. These measurements revealed jumps in the protein concentration at the same location as the zones of discontinuity. The magnitude of these jumps corresponds to changes of the refractive index that can explain the increased scatter of light in the zones of discontinuity.

Crystallins↗
PubMed1989

Incidence of endophthalmitis in Sweden.

A retrospective review of all suspected and proven cases of endophthalmitis (EO) during a period of 18 months in Sweden is presented. This period covered the time of transition in the surgical technique at a large number of clinics. Sixty-two cases of EO were reported out of which 52 were post-operative. A total incidence of post-operative endopthalmitis (POE) was found to be 0.33%. The incidence of culture proven POE was however only 0.06%. No cultures or only conjunctival cultures had been taken in 32 (61.5%). S. epidermidis and S. aureus comprised the majority of isolates. No case of fungal EO was reported. The number of posttraumatic EO was low.

Adolescent↗
PubMed1989

Visual outcome of endophthalmitis in Sweden.

A retrospective study of 62 cases of clinically diagnosed endophthalmitis (EO) reported from 24 clinics in Sweden was carried out. Both culture negative and positive cases were included. The function of the eye was lost in 34% of all cases, while vision better than 0.1 was preserved in 41% cases. Staph. epidermidis positive and culture negative cases were associated with better visual results. The majority of eyes with cultures positive for Staph. aureus were lost or became blind. Intravitreal injection of antibiotics and vitrectomy was generally reserved for more severe cases often involving a delay in their institution. A combination of topical and systemic steroids gave better results than no steroids or only topical steroid administration.

Endophthalmitis↗
PubMed1979

Human traumatic cataract. A quantitative microradiographic and electron microscopic study.

Six cases representing different stages of cataract formation secondary to eye trauma were subjected to quantitative microradiographic or electron microscopic examination. Anterior and posterior subcapsular cataracts were found to contain extensively swollen lens fibers in the subcapsular cortex. Microradiographic measurements revealed a reduced concentration of dry mass in the subcapsular cortex around the whole circumference of the lens. The inner cortex and the nucleus appeared normal both microradiographically and electron-microscopically. Two of the examined cases had an opaque-cataract membrane and one had a Soemmerring's ring. The opaque membranes consisted of irregular masse of degenerated lens fiber material as well as regenerated lens epithelial cells. A wide range of dry mass concentration was found in the opaque membrane that was studied microradiographically. Alterations in morphology and dry mass concentration are more than sufficient to explain the development of opacification in traumatic cataract.

Adolescent↗
PubMed1979

Experimental traumatic cataract. I. A quantitative microradiographic study.

Traumatic cataract was induced in rat and rabbit. The progression of the posterior subcapsular cataract and the wound healing were followed by quantitative microradiography. This method makes it possible to determine the dry mass content and to calculate the refractive indices in the lens. In the injured rat lens a reduced dry mass concentration was determined in both the wound region and the posterior subcapsular region immediately after trauma. During the first week a subcapsular opacity was observed to enlarge. This opacification always corresponded to a reduction in the subcapsular concentration of dry mass. This reduced content of dry material, mainly consisting of protein, is interpreted as a hydration of the subcapsular cortex. In the rabbit lens a much larger injury had to be made in order to cause any posterior cataract. The same reduction in the content of dry material was determined in regions corresponding to opacitices but the reduction was less pronounced than in the rat lens. The border zones between different concentrations of dry mass are suggested to be the main sources of scattered light in the traumatic cataract.

Animals↗
PubMed1979

Experimental traumatic cataract. II. A transmission electron microscopy and extracellular tracer study.

Lens changes caused by injury to the anterior part of the lens were studied with Procion yellow as an extracellular tracer and by transmission electron microscopy at different time intervals after trauma. Both rats and rabbits were used. The findings were related to the slit-lamp appearance of the wounded lenses. In the rat lens a posterior subcapsular cataract developed within the first hour after trauma. Within 1 hr after injury the fluorescent tracer was seen at the wound but was also conspicuous at the posterior pole. Swelling of lens fiber cells and the formation of large syncytical aggregates were found as the posterior opacity enlarged. These changes reached the anterior subcapsular cortex via the equatorial cortex after about 1 month. In the rabbit lens a slight cellular swelling was seen in the subcapsular cortex. Only in one of 15 lenses a posterior subcapsular opacity developed after about 1 week in spite of a large wound. The uptake of Procion yellow was most prominent in the wound area and was never observed at the posterior pole. In both species, no further penetration of the dye occurred through the wound after the epithelium, by regeneration, had sealed the wound. The importance of epithelial wound sealing and that of a restored cellular barrier at the posterior pole are discussed as well as the significance of these factors in the cataract progression.

Animals↗
PubMed1977

Formation of after-cataract by regeneration of human and rabbit lens epithelium in tissue culture.

Regeneration of lens epithelium on the lens capsule was studied in tissue culture. The entire capsule with attached epithelium was taken from rabbit lenses and from human lenses with cataract. Generally, the epithelium grew in a monolayer but multilayered masses of cells were also seen. Most lens fibers degenerated during the first days and formed spherical membrane enclosed vesicles containing cytoplasm but no nuclei. The lens fiber remnants, together with regenerating epithelium, created structures that were similar in many ways to the clinical appearance of after-cataract.

Animals↗