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Biomedical subjects

W M Jay

Publications and source records attributed to W M Jay.

At least 37 records · Page 2Linked to original sources
PubMed1986

Effect of honan intraocular pressure reducer on ocular and optic nerve blood flow in phakic rabbit eyes.

The Honan Intraocular Pressure Reducer (HIPR) was applied to rabbit eyes for 30 min at pressure settings of 0, 30, 50, or 100 mmHg. Ocular blood flow was measured using (85Sr) radioactively labelled 15 micron microspheres either with the HIPR applied to the eye or 15 min after removal. Intraocular pressure was measured before applying the HIPR, immediately after removal, or 15 min after removal. At all pressure settings, the HIPR significantly lowered the IOP (P less than or equal to 0.05) both immediately and 15 min after removal. At all pressure settings, except 0 mmHg, blood flow was significantly (P less than or equal to 0.05) both immediately and 15 min after removal. At all pressure settings, except 0 mmHg, blood flow was significantly (P less than or equal to 0.05) lower with the HIPR applied compared to 15 min after removal.

Animals↗
PubMed1986

Effect of digital massage on intraocular pressure and ocular and optic nerve blood flow.

The effect of digital massage on intraocular pressure and ocular and optic nerve blood flow was studied in anaesthetized rabbits. Digital massage was performed for 15 min, with pressure release for 15 seconds after each 45 seconds of massage. Blood flow was measured in the iris, ciliary processes, choroid, retina, and optic nerve using (85Sr)-labelled microspheres. Blood flow was determined during massage, 2 min after, or 15 min after massage. Intraocular pressure was measured before, immediately after, and in one group, 15 min after massage. Immediately after digital massage, intraocular pressure was significantly lower, but 15 min after it was not significantly reduced. At both 2 min and 15 min after digital massage, compared to during massage, blood flow was significantly higher in all tissues studied.

Animals↗
PubMed1986

Further studies on the effect of retrobulbar epinephrine injection on ocular and optic nerve blood flow.

The effect of retrobulbar epinephrine administration on ocular and optic nerve blood flow was studied in phakic rabbit eyes using a radioactive microsphere (85Sr) technique. Blood flow measurements were performed either 5 minutes or 30 minutes after retrobulbar injection of 10 microliter of a 2% (base) epinephrine bitartrate solution to the right eye of each rabbit. Blood flow was determined for the iris, scraped ciliary processes, choroid, retina, and optic nerve. Five minutes after retrobulbar injection, there was no statistically significant (P greater than 0.05) difference in epinephrine-treated eyes compared to contralateral control eyes that received 10 microliters of retrobulbar saline. Thirty minutes after injection, eyes receiving retrobulbar epinephrine had a statistically significant (P less than 0.05) fall in blood flow to the iris and scraped ciliary processes, but not to the choroid, retina, or optic nerve.

Animals↗
PubMed1986

The effect of retrobulbar lidocaine injection on ocular and optic nerve blood flow.

The effect of retrobulbar lidocaine administration on ocular and optic nerve blood flow was studied in phakic rabbit eyes using a radioactive microsphere (85Sr) technique. Blood flow measurements were performed 15 minutes after retrobulbar injection of 40 mg of lidocaine in ethanol to the right eye of each rabbit. Blood flow measurements were determined for the iris, scraped ciliary processes, choroid, retina, and optic nerve. There was no statistically significant (P less than 0.05) difference in lidocaine treated eyes compared to contralateral control eyes. An identical volume of retrobulbar ethanol alone had no effect on regional blood flow.

Animals↗
PubMed1986

Bilateral sixth nerve pareses with temporal arteritis and diabetes.

A 78-year-old white woman presented with a 1-month history of neck and right shoulder pain and a 12-day history of acute horizontal diplopia. On examination, bilateral sixth nerve pareses were present, right greater than left. On evaluation, the patient was noted to have normal fasting blood sugars, but moderately elevated blood sugars after a glucose load. A temporal artery biopsy was performed which was positive. Whether diabetic or arteritic, bilateral sixth nerve pareses resulted in our patient seeking medical attention. By considering temporal arteritis, it is possible that blindness was avoided.

Abducens Nerve↗
PubMed1985

Effect of applying the Honan intraocular pressure reducer before cataract surgery.

We studied 48 patients undergoing cataract extraction with local anesthesia. In 41 patients, after administering the retrobulbar injection, we applied the Honan intraocular pressure reducer for seven to ten minutes at a pressure setting of 30 mm Hg. Of these 41 patients, 13 received 3-ml injections, 14 received 4-ml injections, and 14 received 5-ml injections. No differences in intraocular pressure related to the quantity of retrobulbar injection were noted. After retrobulbar injection, the mean intraocular pressure for the study population as a whole increased 4.4 mm Hg; after application of the Honan device, it decreased 6.2 mm Hg. In a control group of seven patients, who received 4-ml retrobulbar injections but no applications of the Honan device, mean intraocular pressure increased 6.1 mm Hg immediately after retrobulbar injection and decreased only 0.7 mm Hg after seven to ten minutes.

Bupivacaine↗
PubMed1985

Pharmacokinetic analysis of intravitreal ceftriaxone in monkeys.

Ocular toxic effects of intravitreally injected ceftriaxone sodium and its rate of clearance after a single dose were studied in rhesus and cynomolgus monkeys. Doses of 2, 2.5, and 3 mg/0.1 mL were injected into the vitreous cavity. Electroretinograms performed 15 minutes, 24 hours, one week, and two weeks after injection were not significantly different from preinjection electroretinograms. Lens opacification occurred in one eye receiving 2.5 mg of ceftriaxone. Histopathologic findings in the retina were normal in all eyes injected intravitreally. Levels of ceftriaxone after a 2-mg intravitreal dose were 609 mg/L at 0 hours, 434 mg/L at 24 hours, and 19 mg/L at 100 hours in the vitreous; and 1 mg/L at 0 hours, 116 mg/L at 24 hours, and 9 mg/L at 100 hours in the aqueous.

Animals↗
PubMed1985

Effect of inoculum size on the induction of endophthalmitis in aphakic rabbit eyes.

A reproducible animal model is necessary to examine the use of antimicrobial agents for prophylaxis and treatment of bacterial endophthalmitis. We determined the minimum inoculum size of S. aureus and P. aeruginosa that consistently produced endophthalmitis when injected into aphakic rabbit eyes immediately following surgery. Both anterior chamber and intravitreal injections were examined. For S. aureus, an intravitreal inoculum of 19.3 +/- 7.5 CFU and an anterior chamber inoculum of 50.5 +/- 4.0 CFU were required. For P. aeruginosa, an intravitreal inoculum of 5.5 +/- 2.6 CFU and an anterior chamber inoculum of 97.5 +/- 10.7 CFU consistently produced a fulminant infection. Lower inocula of both bacteria produced endophthalmitis in both locations, but the effect was inconsistent.

Animals↗
PubMed1985

The effect of naproxen on the ocular inflammatory response following extracapsular lens extraction in rabbits.

Naproxen effects on the ocular inflammatory response following extracapsular lens extraction were studied in rabbits. Twelve hours before surgery, rabbits were given 20 mg of a 5 mg/ml naproxen suspension by gavage. A maintenance dose of 10 mg naproxen 3 times per day was started on the day of lensectomy and continued throughout the entire observation period. Phakic and aphakic control rabbits received no drug suspension. Central corneal thickness and intraocular pressure measurements were determined pre-operatively, at 4 and 24 h post-operatively and every 24 h thereafter. Four groups of rabbits, sacrificed at 24, 48, 72, and 168 h after lensectomy, had anterior chamber paracentesis performed for PMN (polymorphonuclear leucocyte) counts and determination of protein content. A 5th group had both paracentesis and iris-ciliary body excision for PGE2 assay at 24 h. No parameter was significantly altered by the naproxen regimen compared to untreated rabbits.

Animals↗
PubMed1985

The effect of retrobulbar epinephrine injection on ocular and optic nerve blood flow.

The effect of retrobulbar epinephrine administration on ocular and optic nerve blood flow was studied in phakic and aphakic rabbit eyes using a radioactive microsphere (85Sr) technique. One hour before blood flow determination, 10 microliter of a 0.2% (base) epinephrine bitartrate solution was administered to the right eye of each experimental rabbit by the retrobulbar route. For control rabbits, 10 microliter of saline was injected retrobubarly. Blood flow measurements were determined for the iris, scrap[ed ciliary processes, choroid, retina, and optic nerve. Neither optic nerve nor ocular blood flow was altered by this dose which is approximately the dose used in retrobulbar injections in humans.

Animals↗
PubMed1985

Alterations in ocular and optic nerve blood flow during intraocular surgery in aspirin pretreated rabbits.

The effect of intraocular surgery on ocular and optic nerve blood flow was determined in rabbits either untreated or pretreated with aspirin. Surgery was either extracapsular lens extraction through a 100 degrees corneal incision or a sham-operation in which a 45 degrees corneal incision was performed and the lens left in place. In both cases, the incisions were not sutured and the intraocular pressure remained zero for one hour. A (85Sr) radioactive microsphere technique was used to measure blood flow in the iris, scraped ciliary processes, retina, choroid, and optic nerve. In rabbits not receiving aspirin pretreatment, blood flow was statistically increased in all portions of the eye, except the retina and optic nerve, studied for sham-operated eyes, and in the iris and optic nerve in the lens extraction group. In rabbits pretreated with aspirin, blood flow remained at normal levels. These results are consistent with the hypothesis that prostaglandins released during ocular surgery cause increased ocular tissue blood flow.

Animals↗
PubMed1985

Periodic alternating nystagmus clearing after cataract surgery.

A 60-year-old man developed periodic alternating nystagmus in association with decreased vision due to cataracts. Prior to surgery, vision was limited to hand motion only in both eyes. An extracapsular cataract extraction with insertion of a posterior chamber intraocular lens was performed in the patient's left eye. On the first postoperative day, vision was 20/60 in the left eye and the nystagmus was absent with both eyes open. Periodic alternating nystagmus that occurs with poor vision is related to a loss of fixation. Surgery aimed at improving the visual status may be effective in extinguishing the nystagmus.

Cataract↗
PubMed1984

Ocular pharmacokinetics of ceftriaxone following subconjunctival injection in rabbits.

Aqueous and vitreous kinetics were studied after anterior subconjunctival injection of 100 mg of ceftriaxone sodium in phakic and aphakic rabbit eyes. Mean peak ceftriaxone concentrations (microgram per milliliter +/- SE, n = 3 to 5 rabbits per determination) were as follows: phakic eyes, 159.5 +/- 42 at one hour in aqueous humor and 25.3 +/- 6.6 at two hours in vitreous fluid; aphakic eyes, 105.1 +/- 20.5 at one hour in aqueous humor and 43.1 +/- 15.4 at one hour in vitreous humor. The ability of ceftriaxone to eliminate an incipient bacterial infection was also evaluated. Ten aphakic rabbits were challenged intravitreally with 700 colony-forming units of Staphylococcus aureus. Six of the ten immediately received subconjunctival injections of ceftriaxone sodium (100 mg). At 48 hours following the challenge, all four control eyes yielded greater than 5.6 X 10(5) colonies per milliliter. In the six eyes receiving ceftriaxone, five were sterile and one yielded 1.4 X 10(2) colonies per milliliter.

Animals↗
PubMed1984

Intravitreal ceftriaxone in a rabbit model. Dose- and time-dependent toxic effects and pharmacokinetic analysis.

Ceftriaxone's toxic effects were assessed in albino rabbits after intravitreal injection. Doses up to 5 mg did not alter the B-wave amplitude. Following 7.5-and 20-mg doses, B-wave amplitude ratios were depressed at 24 hours and normal at seven and 14 days. A 50-mg dose caused a temporarily flat B-wave 24 hours after injection. At two weeks this ratio exhibited a moderate increase but remained 2 SDs below the mean preinjection ratio. Eyes receiving up to 20 mg were normal histologically at 14 days. A 50-mg dose induced generalized retinal edema and disruption of the retinal layers 24 hours after injection; at two weeks there were no histologic changes in the retina. Immediately after a 2-mg intravitreal injection, vitreous ceftriaxone levels were 1,345 +/- 4.9 mg/L; by 72 hours they had decreased to 17.6 +/- 1.4 mg/L. The mean peak aqueous level was 80.2 +/- 12.2 mg/L at 72 hours.

Animals↗
PubMed1984

Effect of topical epinephrine and timolol on ocular and optic nerve blood flow in phakic and aphakic rabbit eyes.

The effects of 4% epinephrine bitartrate and 0.5% timolol on ocular and optic nerve blood flow were studied in phakic and aphakic rabbit eyes using a radioactive microsphere (85Sr) technique. Either epinephrine or timolol was given topically as eight drops in the hour immediately preceding blood flow measurements (one drop every 7.5 minutes). Epinephrine decreased anterior uveal blood flow in both phakic and aphakic eyes, whereas timolol exhibited no effect. Retinal and choroidal blood flow were not affected by either timolol or epinephrine in phakic eyes. In aphakic eyes, epinephrine increased choroidal blood flow without altering retinal blood flow, whereas timolol increased both retinal and choroidal blood flow. Optic nerve blood flow was increased in epinephrine treated phakic and aphakic eyes and also in timolol treated aphakic eyes.

Animals↗
PubMed1984

A revised technique for extracapsular lens extraction in the rabbit.

The surgical procedure described here for extracapsular lens extraction utilizes a bent 25 gauge needle as an irrigating cystotome , a 100 degrees superior clear corneal incision, a single clean incision of the lens capsule, a muscle hook for expression of the nucleus, no cortical cleanup, and interrupted 9-0 nylon sutures to close the incision. We have found it a simple and effective technique which utilizes inexpensive instruments commonly available in an ophthalmology department or ophthalmic research laboratory.

Animals↗
PubMed1984

Iontophoresis of gentamicin into aphakic rabbit eyes. Sustained vitreal levels.

The authors evaluated the intraocular penetration of gentamicin (50 mg/ml) into aphakic rabbit eyes following anodal iontophoresis (0.75 mA for 10 min). Gentamicin levels were determined at 0.5, 4, 8, 16, and 24 hrs after iontophoresis (n = 6 eyes for each time) using an agar diffusion bioassay. Peak levels of 72.04 +/- 6.1 (means +/- SE) micrograms/ml for the corneas and 77.8 +/- 3.0 micrograms/ml for the aqueous humor were obtained at 30 min after iontophoresis. The peak vitreous level was 10.4 +/- 0.4 micrograms/ml, which was found at 16 hrs after iontophoresis. Therapeutic levels of 6.2 +/- 3.0 micrograms/ml were still present in the vitreous humor 24 hrs after iontophoresis. Iontophoresis appears to be an effective noninvasive method for delivering therapeutic levels of gentamicin into ocular tissues and fluids of the aphakic rabbit eye.

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