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Biomedical subjects

B T Philipson

Publications and source records attributed to B T Philipson.

At least 19 recordsLinked to original sources
PubMed1998

Endophthalmitis after cataract surgery: risk factors relating to technique and events of the operation and patient history: a retrospective case-control study.

OBJECTIVE: This study aimed to investigate the relationship between postoperative endophthalmitis and current changes in the cataract operative technique. DESIGN: A retrospective case-control study. PARTICIPANTS: The 22,091 cataract operations performed from 1990 through 1993 at St Eriks Hospital formed the basis for this investigation. In a random fashion, 220 control subjects were selected to be compared with the endophthalmitis cases. MAIN OUTCOME MEASURES: Numerous variables pertaining to the cataract extraction procedure and to the ocular and general health of patients with cataracts were analyzed regarding the development of postoperative intraocular infection. Patient age, presence of diabetes or immunosuppression, type of cataract extraction and intraocular lens (IOL), and intraoperative or postoperative complications were the principal variables assessed. RESULTS: Fifty-seven patients with endophthalmitis were diagnosed, resulting in an overall frequency of 0.26%. Immunosuppressive treatment (P = 0.019), wound abnormality (P = 0.03), and the use of IOLs without a heparinized surface (P = 0.0023) were the only significant risk factors found in a logistic regression model. CONCLUSIONS: The results suggest that cataract operating practice may alter the risk for endophthalmitis in that implanting a heparinized IOL and creating a tight section both seem to provide protection against this dreaded complication. Regarding patient history, an increased susceptibility was found among subjects treated with immunosuppressants. Designing a prophylactic protocol that protects against endophthalmitis more efficiently than did the study prophylaxis of 20 mg of subconjunctival gentamicin, is important not only for this patient subgroup but also for the cataract operated population at large.

Aged↗
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↗
PubMed1986

Nuclear vacuoles in nuclear cataract.

The human lens nucleus has always been described as a homogeneous part of the lens, and if any distinct opacities are found, these are considered to be congenital. However, in lenses with nuclear cataract, both of senile type and those induced by hyperbaric oxygen, we have found relatively transparent vacuoles in the nucleus of similar appearance as cortical vacuoles. In cataracts induced by hyperbaric oxygen the vacuoles were reversible to some extent. The vacuoles have been investigated with slit-lamp photography and quantitative microradiography. Nuclear vacuoles were found in 11 out of 25 patients treated with hyperbaric oxygen compared to 19 out of 100 pre-operatively examined senile nuclear cataracts. In the microradiographs the vacuoles appeared as dark rounded areas with a lower dry mass content (approximately 0.30 g X cm-3) than the surroundings (approximately 0.50 g X cm-3).

Adult↗
PubMed1986

Unscheduled DNA synthesis in lens epithelium after in vivo exposure to UV radiation in the 300 nm wavelength region.

A quantitative autoradiographic method was developed to study the pattern of DNA synthesis in the rat lens epithelium after in vivo exposure to UV radiation in the 300 nm wavelength region. It was found that UV radiation (peak transmission = 298 nm, half-width = +/- 10 nm) induces unscheduled DNA synthesis and that the proportion of nuclei in S-phase concurrently is reduced indicating an inhibition of the scheduled DNA synthesis. The registered unscheduled DNA synthesis is believed to be excision repair of DNA damage induced by the UV radiation. Excision repair in lens epithelial cells could be one mechanism involved in the correlation between exposure to sunlight and cataracts.

Animals↗
PubMed1986

Progressive microscopical changes in the closed system incubated rat lens.

A phase contrast microscopy investigation of 18 cultured rat lenses was undertaken. After an initial latent phase, the outline of the epithelial cells anteriorly became enhanced and posteriorly the lens fibers began to swell. This was followed by an anterior and posterior subcapsular accumulation of fluid, epithelial swelling and formation of posterior subcapsular vacuoles. At the end of the incubation period, no increase in the light dissemination from the lens was observed. It is concluded, that, when these changes are taken into account, the closed system cultured rat lens is an excellent and applicable model for studying the induced progressive changes in the microstructure of the living lens due to different agents.

Animals↗
PubMed1985

Cataract in retinitis pigmentosa. An analysis of cataract surgery results and pathological lens changes.

The result of cataract surgery and lens pathoanatomical examination were presented in patients with retinitis pigmentosa (RP). A retrospective study of 24 cataract extractions in 15 RP patients was carried out, with special regard to visual outcome and surgical complications. The results were compared to an age matched randomly selected control group. In the retinitis pigmentosa group the post-operative visual acuity was generally good, and the surgical complications except for one case of central venous thrombosis were not more frequent than in the control group. Seven lenses from 5 patients with RP were analysed using transmission electron microscopy and quantitative microradiography. In the lenses with a progressive subcapsular edema, extensive extracellular vacuolization was found in the lens epithelium. Focal degeneration of epithelial cells was seen both in the more stationary posterior subcapsular cataracts and the progressive subcapsular cataracts. Different degrees of mitochondrial swelling was found in the epithelial cells of the stationary cataracts. The subcapsular lens fiber changes consisted of an extensive swelling of hydrated cells together with a significant reduction in their dry mass content. Migrating elongated nuclei-containing cells were found on the posterior capsule in both stationary and progressive cataracts.

Adult↗
PubMed1984

Sodium hyaluronate in cataract surgery. II. Report on the use of Healon in extracapsular cataract surgery using phacoemulsification.

Healon has been used in a prospective study as a surgical device for extracapsular cataract extraction using Kelman's phacoemulsification technique. The study comprised 38 patients divided into two groups. Healon and balanced salt solution (BSS) were randomly applied and the patients were age-matched. The emulsification was done in the anterior chamber. Healon is shown to have a protective effect on the cornea as judged by corneal thickness measurements and by endothelial cell counts. Healon facilitated the procedure in several ways. In this study no attempt was made to remove Healon from anterior chamber at the end of surgery. It cannot be excluded that Healon may occasionally cause increased intraocular pressure. With regard to postoperative inflammatory reaction and wound healing, no side effects have been observed after use of Healon.

Adult↗
PubMed1984

Sodium hyaluronate in cataract surgery. I. Report on the use of Healon in two different types of intracapsular cataract surgery.

Healon has been used in a prospective study as a surgical device for two cataract surgical methods. The study comprised 80 patients divided into two groups. In each group Healon and balanced salt solution (BSS) was randomly applied in two age-matched patient subgroups. The surgical procedures were intracapsular cataract extraction (ICCE) with corneoscleral incision and ICCE with corneal incision. Healon is shown to have a protective effect on the cornea as judged by corneal thickness measurements and by endothelial cell counts. Healon facilitated the surgical procedure in several ways. No side effects, either with regard to intraocular pressure or to postoperative inflammatory reaction have been observed.

Aged↗
PubMed1981

Human lens epithelium in normal and cataractous lenses.

Epithelial cell appearance and cell size were studied in intact, unfixed, and unstained human lenses. Ten normal and 24 cryoextracted senile or presenile cataractous lenses, all with subcapsular cataract, were examined. The cell size of the transparent normal lenses showed little variation. However, in the cataractous lenses, a wide range was found in mean cell size of different lenses and variation in cell size within the individual lenses. No correlation was observed between cell size and degree of subcapsular cataract or combination of cataract type.

Aged↗
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↗