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Biomedical subjects

G Trope

Publications and source records attributed to G Trope.

13 recordsLinked to original sources

Surgical repair of skull fractures in four horses using cuttable bone plates.

Three horses with severely comminuted, open facial bone fractures and one horse with a comminuted, open orbital rim fracture were referred for treatment. Severe facial bone asymmetry and epistaxis were apparent in all cases and subcutaneous emphysema was present in two, however physical and neurological examinations were otherwise normal. Radiography and endoscopy were of some use in assessing the degree of damage, although the true extent of the damage was more apparent at surgery. Surgical reduction of the fractures was recommended to maximise cosmetic and functional outcome. After surgical debridement and reduction of the fractures the bone fragments remained unstable and were not amenable to stabilisation with interfragmentary wires alone, so 2 mm cuttable bone plates were used to maintain fracture alignment. Screw migration occurred in three horses and in one of these horses the plate had to be removed. Other complications were minor and in all horses the fractures healed with good cosmetic and functional outcome. The use of cuttable bone plates should be considered as a reasonable alternative to inter-fragmentary wiring for unstable, comminuted fractures of the facial bones, even where fractures are open.

Animals↗

Analysis of myocilin mutations in 1703 glaucoma patients from five different populations.

A glaucoma locus, GLC1A, was identified previously on chromosome 1q. A gene within this locus (encoding the protein myocilin) subsequently was shown to harbor mutations in 2-4% of primary open angle glaucoma patients. A total of 1703 patients was screened from five different populations representing three racial groups. There were 1284 patients from primarily Caucasian populations in Iowa (727), Australia (390) and Canada (167). A group of 312 African American patients was from New York City and 107 Asian patients from Japan. Overall, 61 different myocilin sequence variations were identified. Of the 61 variations, 21 were judged to be probable disease-causing mutations. The number of probands found to harbor such mutations in each population was: Iowa 31/727 (4.3%), African Americans from New York City 8/312 (2.6%), Japan 3/107 (2.8%), Canada 5/167 (3.0%), Australia 11/390 (2.8%) and overall 58/1703 (3. 4%). Overall, 16 (76%) of 21 mutations were found in only one population. The most common mutation observed, Gln368Stop, was found in 27/1703 (1.6%) glaucoma probands and was found at least once in all groups except the Japanese. Studies of genetic markers flanking the myocilin gene suggest that most cases of the Gln368Stop mutations are descended from a common founder. Although the specific mutations found in each of the five populations were different, the overall frequency of myocilin mutations was similar ( approximately 2-4%) in all populations, suggesting that the increased rate of glaucoma in African Americans is not due to a higher prevalence of myocilin mutations.

Asian People↗

Determining Ontario's supply and requirements for ophthalmologists in 2000 and 2005: 1. Methods.

BACKGROUND: We performed a study to determine the supply of and requirements for ophthalmologists in Ontario in 2000 and 2005. In this paper we describe our methods. METHODS: The future supply of ophthalmologists was estimated by means of iterative multiple regression analysis using the baseline number of ophthalmologists, the number of ophthalmology residents and the numbers of ophthalmologists entering and exiting the workforce between 1989 and 2004. Data were obtained from the Ontario Physician Human Resource Data Centre, Statistics Canada, the Ontario Ministry of Finance and residency program directors of Ontario universities. We calculated requirements using four models. The physician:population ratio method used an ophthalmologist:population ratio (1:29,650) proposed by the Royal College of Physicians and Surgeons of Canada and Statistics Canada population projections for 2000 and 2005. The utilization-based, substitution and needs-based models used Ontario Health Insurance Plan data for 1995. The supply and requirements are expressed as full-time equivalents, defined as the average number of minutes worked by ophthalmologists in 1995. The 401 ophthalmologists practising in Ontario in 1995 accounted for 452 full-time equivalents. INTERPRETATION: Incorporating the results of several requirement models increases the reliability and acceptability of estimates of physician workforce requirements.

Female↗

Determining Ontario's supply and requirements for ophthalmologists in 2000 and 2005: 2. A comparison of projected supply and requirements.

BACKGROUND: To determine whether the projected supply of ophthalmologists in 2000 and 2005 in Ontario will be matched by the predicted requirements. METHODS: Described in the accompanying paper (page 74). RESULTS: Multiple regression analysis predicted a supply of 485 +/- 15 full-time-equivalent (FTE) ophthalmologists in 2000 and 476 +/- 14 FTEs in 2005. Except for the needs-based method of determining requirements, which generated a figure of 524 +/- 16 to 533 +/- 16 FTEs, the requirement methods yielded estimates that were within the range of the projected supply for 2000 (physician:population ratio method 458, utilization-based method 500 +/- 15 and substitution method 470 +/- 14 to 490 +/- 15). For 2005, only the physician:population ratio method gave an FTE requirement estimate (489) that was in keeping with the projected supply. The other models gave FTE estimates that were higher than the projected supply (utilization-based model 559 +/- 17, substitution model 526 +/- 16 to 548 +/- 16, and needs-based model 585 +/- 18 to 596 +/- 18). INTERPRETATION: The reduction in the number of ophthalmology residents in Ontario that began in 1994 will not affect the short-term requirements for ophthalmologists but may result in fewer ophthalmologists than will be necessary to fulfil Ontario's requirements in 2005 and beyond. Possible solutions include doubling the number of residency positions beginning in 1999.

Female↗

Fifty:fifty poly (DL glycolic acid-lactic acid) copolymer as a drug delivery system for 5-fluorouracil: a histopathological evaluation.

Fifty:fifty poly (DL glycolic acid-lactic acid) copolymer (PGLA) is a potentially useful depot drug delivery system for 5-fluorouracil (5-FU). The purpose of this study was to evaluate the fibroinflammatory reaction induced by this polymer. Polymer discs without 5-FU were inserted subconjunctivally in one eye of each of two guinea pigs and four pigmented rabbits (control group), and discs containing 20% 5-FU were inserted subconjunctivally in both eyes of nine pigmented rabbits (study group). The tissue reaction to the copolymer did not differ between rabbits and guinea pigs, with a mild mixed inflammatory reaction 1 week after implantation. At 2 weeks a thin fibrous capsule surrounded the discs, with no change in the amount of inflammation. At 4 weeks the disc had disintegrated, but residual polymer was seen within multinucleated giant cells in the episcleral tissue. Granulation tissue and inflammatory responses were mild. Less inflammation and fibrosis occurred in the study eyes, although the pattern of response was similar in the two groups. The inflammatory response to PGLA was markedly less than that to implanted collagen shields, and our findings suggest that PGLA implant is a promising ocular drug delivery system for 5-FU after filtration surgery.

Animals↗

Ultrasound biomicroscopic features of pigmentary glaucoma.

We have developed a device capable of producing subsurface images in eyes at microscopic resolution. We call this method "ultrasound biomicroscopy." We examined 19 patients with pigmentary glaucoma or pigmentary dispersion syndrome using ultrasound biomicroscopy. Ten patients were found to have concave irides with small distances between the back of the iris and the zonule. In these patients iris-lens contact was greater than in patients without iris concavity and healthy patients. Nine patients did not show iris concavity or increased iris-lens contact. The finding of iris concavity and increased iris-lens contact is compatible with a theory of reverse pupil block producing intermittent iris-zonule touch, with a valve effect preventing posterior flow of aqueous. This theory was supported by the loss of concavity following iridotomy in three patients. The force that produces a reversal of the normal pressure gradient remains unclear, but recent evidence suggests that accommodation plays a major role. The patients who did not show iris concavity and increased iris-lens contact may have been examined at a time when these forces were not acting or had ceased to act.

Adult↗

Primary angle closure glaucoma and retinitis pigmentosa.

The prevalence of primary open angle glaucoma in patients with retinitis pigmentosa ranges from 2-12%. To the best of our knowledge the prevalence of primary angle closure glaucoma in retinitis pigmentosa patients has not been reported. This study was conducted to determine the prevalence of primary angle closure glaucoma in patients with retinitis pigmentosa and the relationship between the two. We reviewed 538 retinitis pigmentosa patients' charts seen between 1974-1987, in the Ocular Genetic Clinic in the Hospital of Sick Children, Toronto, Canada. The prevalence of primary angle closure glaucoma in our retinitis pigmentosa patients over 40 was 1.03%. We also reviewed three patients with primary angle closure glaucoma and retinitis pigmentosa. One patient had typical bilateral retinitis pigmentosa, one patient had bilateral sector retinitis pigmentosa, and one patient had unilateral retinitis pigmentosa and primary angle closure glaucoma in the same eye. Our data indicate that there is a strong association between retinitis pigmentosa and primary angle closure glaucoma.

Adolescent↗

Value of Humphrey perimetry in the detection of early chloroquine retinopathy.

Various forms of perimetry are used to confirm Chloroquine retinopathy diagnosed by Amsler grid testing. Little is known about the value of using a red target generated statically. The purpose of this study was to determine the sensitivity and specificity of both red and white perimetry using program 10-2 on the Humphrey automated perimeter. Sixty-nine eyes were tested in total. Fifty eyes were from patients with known early Chloroquine retinopathy with abnormal Amslers. Red perimetry was 91.3% sensitive and 57.8% specific for Chloroquine retinopathy. White perimetry was 78% sensitive and 84% specific for this condition. In conclusion, red Humphrey perimetry was highly sensitive but not highly specific for Chloroquine retinopathy.

Aged↗