Search PubMed⌕ Search

Biomedical subjects

J L Jay

Publications and source records attributed to J L Jay.

At least 19 recordsLinked to original sources
PubMed1992

Calcification of porcine valves: a successful new method of antimineralization.

Despite distinct advantages over mechanical cardiac valve prostheses, the use of bioprosthetic valves remains limited due to poor long-term durability, primarily as a result of tissue calcification. A novel anticalcification process, based on treatment of porcine bioprostheses with a derivative of oleic acid, has been developed by one of us (J.M.G.) (US Patent Number 4,976,733). This process employing 2-aminooleic acid (AOA) was tested in a juvenile sheep model. Terminal studies after a 20-week interval included hemodynamic, radiographic, morphologic, and quantitative tissue calcium analyses. All control valves (n = 4) had thickened, immobile, heavily calcified leaflets, whereas all AOA-treated valves (n = 8) were pliable and free of calcium deposits. Calculated valve orifice areas for controls (0.9 +/- 0.2 cm2) (mean +/- standard error of the mean) was less than for AOA-treated valves (2.0 +/- 0.3 cm2) (p less than 0.05). Radiographic calcification scores were greatly elevated in the control (25.5 +/- 5.6) versus AOA-treated valves (0.5 +/- 0.5) (p less than 0.002). In quantitative mineralization studies, the mean calcium content of the control leaflets was 129 +/- 21 milligrams per gram dry weight cusp tissue versus 7.7 +/- 5.8 mg/g for AOA-treated valves (p less than 0.001). Pathologic examination confirmed heavy calcification in the control leaflets, which was essentially absent in the AOA-treated leaflets. However, cuspal hematomas in areas of structural loosening and surface roughening were noted in AOA-treated valves. This anticalcification process dramatically reduced mineralization of porcine valve prostheses in this model.

Animals↗
PubMed1992

Dapsone therapy for the acute inflammatory phase of ocular pemphigoid.

Oral dapsone was used to treat five patients who presented in the acute inflammatory phase of ocular pemphigoid. The diagnosis was made clinically by identifying cicatricial changes which were in some cases difficult to find. In all cases it was the inflammatory rather than the cicatricial features which responded to treatment. An initial dose of 100 mg/day was effective without toxicity. When 150 mg/day was used patients experienced side effects. A clinical response was obtained after 1-4 weeks and could be maintained on a dose of between 50 mg on alternate days and 100 mg/day. Therapy was withdrawn during remissions which lasted up to 32 weeks but all cases required continuing therapy which has remained effective. Immunopathological examination was carried out on two occasions in all cases and although positive on at least one occasion the results did not correlate with disease activity or treatment. The inflammatory phase of ocular pemphigoid should be added to the list of diseases responsive to dapsone.

Adult↗
PubMed1992

Modification of trabeculectomy to avoid postoperative hyphaema. The 'guarded anterior fistula' operation.

The effect of varying the position of a trabeculectomy fistula on the rate of postoperative hyphaema was studied in a prospective randomised trial. One eye of each of 78 consecutive patients with primary open angle glaucoma and exfoliation glaucoma was allocated to one of two groups. In group A the fistula was fashioned anterior to the scleral spur, entirely in corneal tissue. In group B the fistula included cornea and sclera with trabecular meshwork and scleral spur. Seven out of 39 eyes (18%) in group A developed a postoperative hyphaema with detectable blood level, compared with 22 out of 39 eyes (56%) for group B (p less than 0.001). In addition, the severity of the bleeding was greater in group B, and the three cases of recurrent bleeding were all in this group. Group B patients remained in hospital for an average of 3.9 days, which was significantly longer (p = 0.004) than the average of 2.9 days for group A. This difference was related to the frequency and severity of the hyphaema. The type of dissection or the occurrence of hyphaema did not influence the intraocular pressure at 4 months after surgery.

Aged↗
PubMed1991

Cost analysis of early trabeculectomy versus conventional management in primary open angle glaucoma.

The financial cost of managing primary open angle glaucoma by trabeculectomy at diagnosis was compared with the cost of a more conventional sequence of medical therapy followed by trabeculectomy only in unsuccessful cases. Costs were estimated at 1989 prices for 104 patients studied in a prospective randomised multicentre trial which had been running for eight years. Separate estimates were made for operative costs, inpatient costs, and outpatient costs including visual field tests and medications. Values were adjusted to allow for the observed mortality rate within the group. Conventionally managed patients with bilateral glaucoma required an average total expenditure of 2,570 pounds for the eight year period, compared with 2,560 pounds for those treated by early surgery. In both groups expenditure was greatest in the first year of care, and declined over the eight years. Although early surgery incurred a higher cost within the first year, in subsequent years the conventionally managed group was consistently more expensive and so overall costs were similar. Inpatient care was the most expensive item in both groups (62% of total cost in conventional management, and 77% with early surgery). Our current practice is to admit patients for a shorter period than the average of 7.6 days at the time of this trial. We have therefore produced cost estimates based on a shorter inpatient stay of one and four days per operation, and in both cases early surgery becomes the less expensive strategy. The results have been presented in a form that allows substitution of regional and temporal variations in costs and medical practice.

Costs and Cost Analysis↗
PubMed1991

Quality of vision through diffractive bifocal intraocular lenses.

Two elderly women have each received a monofocal intraocular lens in one eye and a 3M diffractive bifocal intraocular lens in the other eye. Both eyes were shown to have equivalent retinal/neural function by measuring contrast sensitivity to laser interference fringes which bypassed refractive and other defects of the ocular media. The eyes with a bifocal intraocular lens displayed a much greater depth of focus, though at the expense of diminished contrast sensitivity compared with the normal values expected for that age. Simulation experiments suggested that the observed reduction in contrast sensitivity was not adequately explained by a simple reduction in retinal illumination of the in-focus image as might intuitively be expected from the bifocal separation of incident light to two simultaneous focal points. The simultaneous superimposition of the out-of-focus image on the in-focus image must also be considered, since this caused a significant reduction in contrast sensitivity when the retinal illumination was insufficiently above the photopic luminance threshold.

Aged↗
PubMed1990

The increasing frequency of surgery for cataract.

The increasing frequency of cataract operation was investigated by examining the age related cataract extraction rates for Glasgow. Detailed analysis of case records of sample patients over the past decade was carried out to characterise trends in frequency of intraocular lens implantation, age of the patient at operation, preoperative visual acuity and rate of operation on the second eye. Between 1980 and 1987 the rate of cataract operation per thousand increased from 7.1 to 10.5 for patients aged 75 years and over and from 3.6 to 4.2 for those aged 65 to 74 years. There was a marked rise in the number of cataract operations relative to other eye operations between 1977 and 1988, from 19.3% to 37% and this increase was greatest in patients of 70 years and over. The same decade has seen intraocular lens implantation rise from 0% to 94.6% of cataract extractions. Visual acuity data show a significant trend towards operation at a better level of acuity in patients aged 70 years and over (p = 0.028) but not in younger age groups. There was no change in the visual acuity of the fellow eyes and no change in the frequency of operation on the second eye. It appears that cataract surgery is increasing more than can be predicted from the age of the population and this must be recognised in planning the future level of ophthalmology services.

Adult↗
PubMed1990

A hand-held OKP chart for the screening of glaucoma: preliminary evaluation.

Oculo-kinetic perimetry (OKP) uses controlled movements of the patient's eye to position a static test stimulus in the visual field. The test chart consists of a white tangent screen with 23 numbered fixation points located eccentrically at strategic points in relation to a central black spot, which is the test stimulus. As the patient looks at each number in turn, the spot stimulates the retinal areas that are most likely to show early glaucomatous damage. The result is positive if one or more numbers make the spot disappear. Ninety-eight eyes of 54 patients attending a hospital glaucoma clinic were tested with a prototype OKP glaucoma screener and by conventional perimetry. Visual fields plotted conventionally were independently categorised as normal, equivocal and glaucomatous by the perimetrist and the ophthalmologist and these results were further categorised as normal, equivocal or glaucomatous according to whether they were considered abnormal by none, one or both of the observers respectively. The OKP test was positive in (i) 93% of 27 eyes with glaucomatous defects, (ii) 69% of 32 eyes with equivocal loss, (iii) 41% of 39 eyes without previously recognised field loss but having ocular hypertension, a suspicious disc, or contralateral glaucoma, (iv) 9% of 116 eyes from 60 age matched persons accompanying the patients to hospital. If the results were considered in terms of patients not eyes, the OKP test was positive in 85% individuals with glaucomatous field loss in their worse eye and in 12% of the controls. A hand-held OKP chart testing a small set of points and using a constantly exposed stimulus could be a useful tool for the detection of glaucoma in the community.

Evaluation Studies as Topic↗
PubMed1990

The association of Fuchs's corneal endothelial dystrophy with axial hypermetropia, shallow anterior chamber, and angle closure glaucoma.

A series of 24 patients with Fuchs's dystrophy are presented in whom detailed clinical measurement showed an association with axial hypermetropia and shallow anterior chamber. In 14 of these patients one cornea had developed oedema, of which 11 had required penetrating keratoplasty. Comparison of these eyes with the fellow eyes without corneal oedema revealed that the anomalies in measurement were not due to the process of decompensation. These 14 patients were then compared with the remaining 10 patients without corneal oedema in either eye, and a similar profile of anomalous measurements was observed. The whole group of 24 patients were then compared with three separate control groups, and in each case a significant trend towards hypermetropia, short axial length, and shallow anterior chamber was noted. The mean spherical equivalent refractive error in the patients with Fuchs's dystrophy was +2.48 D compared with -0.31 D for controls; corresponding means for axial length were 22.1 mm compared with 23.4 mm; and for anterior chamber depth were 2.2 mm compared with 2.7 mm. Each of these differences was statistically significant, but there was no significant difference for the keratometry measurements between patients and controls. Five of 24 (21%) of the patients had problems related to shallow anterior chambers of whom 3 (12%) had manifest angle closure glaucoma requiring surgical peripheral iridectomy. The aetiology of Fuchs's dystrophy and of ametropia is discussed and possible modes of association outlined. This previously unrecognised association gives a rational basis for the widely accepted practice of combining penetrating keratoplasty with lens extraction and has several other practical implications which are important in the differential diagnosis and treatment of Fuchs's dystrophy and angle closure glaucoma.

Adult↗
PubMed1989

Abnormality of the pattern electroretinogram and pattern visual evoked cortical response in esotropic cats.

In six 3-week-old kittens, the tendon of the lateral rectus muscle of one eye was sectioned under anaesthesia in order to induce an esotropic (nasally-directed) squint. At maturity, the pattern electroretinogram (PERG) and pattern visual evoked response (PVER) were recorded under anaesthesia to phase-reversal at 1.67 Hz of a 0.5c/deg square wave grating pattern of 75% contrast. Refraction was determined by retinoscopy and confirmed by recording the PERG for different trial lenses. The amplitude and time-to-peak of the PERG and PVER were compared between operated and unoperated eyes, and with the responses of one normal and two sham-operated cats. With stimulation of the operated eye, the amplitude of the PVER was consistently reduced by 50% compared with the non-operated eye, confirming that the cats had become amblyopic as a result of the squint. While the appreciable inter-eye variations in the amplitude of the PERG of the normal and sham-operated cats precluded identification of a change in the esotropic cats, there was a consistent prolongation of the time-to-peak of the PERG by 50% with stimulation of the operated eye. This result is consistent with a retinal component to strabismic amblyopia.

Amblyopia↗
PubMed1989

The detection of glaucomatous visual field defects by oculo-kinetic perimetry: which points are best for screening?

Oculo-kinetic perimetry (OKP) uses the patient's ocular movements to position a test stimulus in the visual field. By virtue of its simplicity and low cost, this test could be useful in the screening of glaucoma. The general purpose OKP chart, however, which tests 100 points in the central 25 degrees field, is too time-consuming for this purpose, taking approximately 4-7 minutes per eye. Accordingly, this study was performed to identify the points most likely to detect patients with glaucoma. Fifty-one eyes with glaucomatous visual field defects and 51 non-glaucomatous eyes of age matched individuals were tested by conventional and oculo-kinetic perimetry. At least one of only six points were missed by 82.4% of glaucomatous eyes and by 9.8% of nonglaucomatous eyes. These results, although falling short of the ideal efficiency, are comparable with data published by other research groups using computerised equipment and suggest that, with further development, a specialised OKP chart testing only a small number of points might be valuable in screening for glaucoma.

Adult↗
PubMed1989

The benefit of early trabeculectomy versus conventional management in primary open angle glaucoma relative to severity of disease.

One hundred and sixteen patients with newly diagnosed primary open angle glaucoma were selected for a randomised, prospective, multicentre trial if the untreated intraocular pressure was over 25 mmHg and there was field loss characteristic of glaucoma. Conventional management of medical therapy followed by trabeculectomy in unsuccessful cases was compared with trabeculectomy at diagnosis followed where necessary by supplementary medical therapy. At a mean follow-up of 4.6 years there was no significant difference in visual acuity between the groups but the conventional management group had significantly greater loss of visual field which occurred during the unsuccessful attempt at medical control. The eyes which lost most visual field were those with least field loss at diagnosis and this paradox was attributed to a prolonged attempt at medical control in these eyes because they were thought to have a lower risk of visual field deterioration.

Chi-Square Distribution↗
PubMed1988

Raised intraocular pressure with topical steroids after trabeculectomy.

A prospective study of 87 eyes of 52 patients with primary open-angle glaucoma showed a significant steroid-induced rise in intraocular pressure in the 4 weeks after trabeculectomy in 23% of eyes. The steroid response rate was lower (17%) in those eyes that had trabeculectomy without a prior trial of medical therapy than in those who had surgery only after failure of medical therapy (36%), but this difference just failed to reach statistical significance. The responders were not significantly different from the non-responders as regards level of intraocular pressure or severity of visual field loss at diagnosis. The frequency of response was lower than that expected in the normal and in the glaucoma population and fell further in the late post-operative period when only 3 of 8 previously responsive eyes submitted to re-challenge with topical steroids showed persisting responsiveness. Topical steroids may be the commonest cause of high intraocular pressure in the first weeks or even days after trabeculectomy. Decisions about long-term supplementary medical therapy should therefore only be taken several weeks after withdrawal of the post-operative steroid drops.

Betamethasone↗
PubMed1988

Tissue response to aqueous drainage in a functioning Molteno implant.

The tissue reaction to a functioning Molteno implant has been studied by light microscopy and by scanning and transmission electron microscopy. The material was obtained from an aphakic 83-year-old human eye which required enucleation because of intractable bullous keratopathy, despite well controlled intraocular pressure. The tissue response around the silicone rubber tube was that of simple fibroblastic activity. Around the implant, however, there was fibrous tissue in which necrotic cell debris was prominent. No significant inflammation was observed in this tissue, but the choroid beneath the implant showed a focal inflammatory cell infiltrate. The morphology suggests that the tissue around all surfaces of the implant (450 mm2) is exposed to aqueous, which seems to have a toxic effect on the encapsulating connective tissue. The changes seen in the tissue exposed to draining aqueous are similar to those described in experimental studies of the effect of aqueous on cell growth in tissue culture.

Aged↗
PubMed1988

Early trabeculectomy versus conventional management in primary open angle glaucoma.

The results of a randomised, prospective, multicentre trial of the management of primary open angle glaucoma are presented at up to five years' follow up. Previously undiagnosed cases were selected with intraocular pressure of 26 mmHg or more on two occasions together with field loss characteristic of glaucoma. Analysis was performed on one eye selected at random from each of 99 patients. Conventional medical treatment followed in unsuccessful cases by trabeculectomy (group A) was compared with trabeculectomy at diagnosis followed when necessary by supplementary medical therapy (group B). The life expectancy of these glaucoma patients was found to be similar to that for the local population matched for age and sex. In group A after four years trabeculectomy had been performed in 53% of eyes because medical management had failed to control the disease. The rate of operation was lower in those patients with intraocular pressure less than 31 mmHg and mild relative field loss (17% at three years) than in those with intraocular pressure greater than 30 mmHg and dense scotomas (75% at three years). Early surgery provided much more stable control with fewer changes in treatment than in group A. The group mean intraocular pressure after trabeculectomy was 15.0 mmHg irrespective of the time of operation, and this was significantly lower than the intraocular pressure in those cases thought to be controlled on medical therapy alone at the end of the first year (20.8 mmHg). Early operation provided significantly better protection of visual field, and the extra loss of visual field with delayed operation occurred in the preoperative period. Changes in visual fields were not related to the use of miotics. There was no significant difference in the final visual acuity in the two groups, but six cases in group A lost central fixation because of progressive loss of visual field, and there were no such cases in group B. Cataract occurred in approximately 10% of cases in both groups, but in group A this happened with only half the number of operations and at a shorter postoperative follow-up than in group B. It appears that in cases of primary open angle glaucoma of this severity the risk of delaying operation are significantly greater than those of performing trabeculectomy as the primary treatment.

Aged↗