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Biomedical subjects

C A Harper

Publications and source records attributed to C A Harper.

30 records · Page 2Linked to original sources
PubMed1991

Tissue plasminogen activating factor assisted removal of subretinal hemorrhage.

We used tissue plasminogen activator (tPA) to aid in the surgical evacuation of subretinal hemorrhages. Subretinal hemorrhage secondary to a ruptured retinal macroaneurysm was treated in two patients. The surgical technique involved using a micropipette to fashion a small retinotomy through which tPA was injected into the subretinal space and through which the dissolved clot was removed. Visual acuity improved from counts fingers to 20/50 in one patient and from counts fingers to 20/70 in the other. Three additional patients, with massive subretinal hemorrhages secondary to age-related macular degeneration, were similarly treated. In one, visual acuity improved from counts fingers to 20/400; in two others, visual acuity was stabilized; in the first patient, at 20/300, and in the second patient at 20/400. The use of tPA minimizes surgical manipulation of the sensory retina and greatly reduces the size of the retinotomy required for evacuation of subretinal blood.

Aged↗
PubMed1990

Aging changes in Bruch's membrane. A histochemical and morphologic study.

Using histochemical staining techniques and electron microscopy, the authors have examined the histochemical properties and ultrastructure of Bruch's membrane in 30 human eyes with an age range of 1 to 95 years. The results analyzed in three age groups (0-30 years, 31-60 years, and older than 60 years) show that there is a progressive accumulation of lipids in Bruch's membrane with relation to age. Differences were found in the specific types of lipids in individual eyes. Five eyes stained for neutral lipids alone, four stained predominantly for phospholipids, and nine stained intensely for both neutral lipids and phospholipids. The deposits were associated with the progressive destruction of the native architecture of Bruch's membrane but no correlation was identified between specific inclusions in Bruch's membrane with a particular lipid. These results are significant to age-related macular disease (ARMD), and the lipid rich barrier in Bruch's membrane is implicated as a cause of photoreceptor dysfunction and pigment epithelial detachment.

Adolescent↗
PubMed1989

A comparison of the efficacy of betaxolol and timolol in ocular hypertension with or without adrenaline.

Betaxolol hydrochloride, a selective beta 1-adrenergic blocker, is claimed to be less likely to aggravate chronic obstructive airways disease than timolol maleate, a nonselective beta-blocker. It is not clear which drug is more effective in lowering intraocular pressure (IOP) and how each acts in combination with topical adrenaline. To assess this we conducted a randomised clinical trial on ocular hypertensive patients. Both betaxolol and timolol produced a significant fall in IOP though not in all patients. No significant difference was found between betaxolol and timolol. The addition of dipivefrin gave an additional fall in some eyes only. No significant difference was found between the addition of dipivefrin and adrenaline. Some fellow eyes had a fall in IOP when dipivefrin was added to timolol. It is important to assess the response carefully in each individual eye when using betaxolol or timolol or when adding additional medication.

Adrenergic beta-Antagonists↗
PubMed1989

Occurrence of malignant glaucoma after laser iridotomy.

A case is described of malignant glaucoma with extreme shallowing of the anterior chamber (AC) and an abnormally high intraocular pressure (IOP) following laser iridotomy for acute angle closure glaucoma. The episode followed the use of strong miotic (pilocarpine hydrochloride 4%) and was reversed by mydriatics including phenylephrine hydrochloride. Serial estimation of anterior chamber depth is important in the management of angle closure glaucoma.

Aged↗
PubMed1988

Subclavian steal syndrome. A report of two cases.

Two cases of subclavian steal syndrome are reported. Symptoms included light-headedness or syncope, reflecting vertebrobasilar insufficiency, and in one case, numbness and tingling in the left upper extremity, reflecting ischemia. Many persons with this syndrome are asymptomatic. Key findings include unilaterally decreased pulses and a significant difference in blood pressure between the upper extremities. Arch aortography, the "gold standard" of diagnosis, must be performed before surgical intervention.

Aged↗
PubMed1987

Gout presenting as a popliteal cyst. A case of pseudothrombophlebitis.

A 64-year-old man with progressive swelling and erythema of his right calf preceded by dull aching in the right popliteal fossa was presumed to have deep vein thrombophlebitis. A venogram revealed normal circulation in the right lower leg, and an ultrasound examination of the right popliteal fossa revealed a 2 X 5-cm popliteal cyst. Fluid aspirated from the cyst confirmed the diagnosis of gout. Popliteal cysts associated with gout are rare, and those that rupture, leak, dissect, or enlarge can mimic thrombophlebitis (a phenomenon known as pseudothrombophlebitis). Thus, the primary care physician should consider the diagnosis of popliteal cyst in patients who appear to have deep vein thrombophlebitis.

Diagnosis, Differential↗
PubMed1986

Combined hamartoma of the retina and RPE: an unusual cause of the dragged disc appearance.

Combined hamartoma of the retina and retinal pigment epithelium (RPE), is a rare, benign, congenital fundal lesion which contains a mixture of glial tissue, blood vessels and pigment epithelium. Such tumours are variably pigmented and may be wrongly diagnosed as malignant melanoma or retinoblastoma. We report two cases which were located in the periphery of the fundus and which produced a dragged disc appearance.

Child, Preschool↗
PubMed1977

Usefulness of new analytical reagents demonstrated with coumadin-modified plasma.

Prothrombin, factor X or factor IX were removed specifically from bovine plasma by immunological techniques. Each depleted plasma is responsive to the respective purified component, and was used to follow the blood changes produced in a steer's blood by Coumadin administration. A factor IX-VII reagent was also used to follow changes in factor IX and factor VII activity. It is suggested that the new reagents may have practical value for qualitative and quantitative work in blood coagulation studies.

Animals↗
PubMedDate not supplied

Bioavailability of microsphere-entrapped cyclosporine A in the cornea and aqueous of rabbits.

Extended release of immunosuppressive drugs and sustained drug levels are desirable for the treatment of corneal graft rejection and other ocular immune disorders. This experiment was conducted with biodegradable microspheres containing cyclosporine A to assess their suitability for achieving this goal. Microspheres containing cyclosporine A were prepared using a solvent evaporation process. A mixture of poly(lactic) and poly(glycolic) acid polymers (50:50) and cyclosporine A was dissolved in a mixture of chloroform and acetone. The solution was then emulsified in an aqueous solution of polyvinyl alcohol and stirred for 24 hours to evaporate the organic solvent. The final assayed concentration of cyclosporine A was 15.38 mg/mL. A 0.13 mL aliquot (2.0 mg) of the suspension of the microspheres was injected subconjunctivally in 24 eyes of white New Zealand rabbits. The concentration of cyclosporine A in the aqueous and cornea was measured at 6, 12, 24, 48, 72, and 144 hours after injection (n = 4 for each group). Corneal levels of cyclosporine A ranged from 2392 +/- 70 ng/mL at 6 hours to 1297 +/- 459 ng/mL at 144 hours. The aqueous levels ranged from 110 +/- 0 ng/mL at 6 hours to 62 +/- 11 ng/mL at 144 hours. These data indicate that a microsphere drug delivery system is an effective means of delivering cyclosporine A to the cornea and anterior chamber, and may provide an alternative for the treatment of ocular immune disorders.

Animals↗
PubMedDate not supplied

Compliance with recommendations from a screening programme for diabetic retinopathy.

METHODS: General practitioner compliance with recommendations for patient follow-up after participation in a screening programme for diabetic retinopathy was assessed. Six months after screening with non-mydriatic retinal photography in four areas of Victoria, the genera practitioner of each participant was surveyed if the participant reported no examination for diabetic retinopathy in the past 2 years and if the results of the screening indicated the need for further assessment. RESULTS: Overall, 208 of 253 (82%) completed questionnaires were analysed. A total of 123 (59%) patients were referred by their doctors for further assessment and 97 (79%) of those referred were reported to have complied with the referral. Of the 85 (41%) patients who were not referred for further assessment, 31 (36%) were reported by their doctors to be already under regular review by an ophthalmologist. CONCLUSIONS: Compliance with genera practitioner referrals suggests that this screening programme was effective and a useful means by which to remind general practitioners of the importance of regular eye examinations for people with diabetes.

Australia↗