Biomedical subjects

A Mandell

Publications and source records attributed to A Mandell.

9 recordsLinked to original sources

PubMed1980

Filtering valve implant surgery for eyes wtih neovascular glaucoma.

We performed filtration surgery with a unidirectional, pressure-sensitive valve implant in 40 eyes with neovascular glaucoma. The device consisted of an open Supramid tube (outside diameter 0.58 mm, inside diameter 0.38 mm) sealed to a Silastic tube with a slit valve. The Supramid tube was inserted at the corneoscleral limbus 1 to 4 mm into the anterior chamber and the Silastic portion was located under a lamellar scleral flap. Twenty-seven of 40 eyes (68%) had a postoperative IOP less than or equal to 24 mm Hg with a mean follow-up of 13.8 months. Ten of these 27 eyes required postoperative medical therapy to achieve this level of IOP control. The glaucoma valve implant failed to return IOP to normal in 13 of the 40 eyes (32%), 11 of these as a consequence of scarring of the external bleb.

Adult↗

PubMed1976

The effects of dipivalyl epinephrine on the eye.

We treated one eye each of ten patients with ocular hypertension with dipivalyl epinephrine (DPE), a congener of epinephrine. Pupil size and intraocular pressure were measured before and at intervals up to 240 minutes after instillation of a single drop of DPE in concentrations from 0.005 to 0.5%. Concentrations of 0.025% DPE and greater significantly reduced IOP, and mydriasis was induced by concentrations of 0.1% DPE or greater. Comcentrations of 0.1% DPE, instilled twice daily for one month, significantly reduced intraocular pressure during diurnal testing on days 2 and 31. No toxic side effects were noted. The DPE produced dose-related increases of cyclic adenosine monophosphate in the aqueous humor of rabbits.

Animals↗

PubMed1976

A rocking motion sensor for the blind.

Rocking motion is an unconscious and often unwanted phenomenon exhibited by the blind. It is usually manifested in oscillatory back and forth, side to side, or rotatory movements of the upper torso or head at about 1 Hz rate. Subjects desiring to function unobtrusively in the world of the sighted need to be alerted when rocking so they can control it. The rocking motion sensor incorporates biofeedback and records rock occurrences. A miniature body mounted accelerometer senses body accelerations exceeding 0.1g. These motions during a given period, compared with a presettable "rock threshold", discriminate rocking from normal activities. Sound biofeedback alerts the subject that he has exceeded threshold. Another counting and timing subsystem determines "end of rock" and resets the system. A recorder is provided that records signals only during rocking. Timing information is provided on a separate channel to permit later time line analysis. The rocking motion sensor system utilizes primarily solid state CMOS circuits with a combination of synchronous-asynchronous timing. The recorder is a modified commercial unit. The two units are separate, portable, and belt mounted. Tests have been made and results will be presented.

Biomedical Engineering↗

PubMed1975

The reproducibility of the intraocular pressure response to dexamethasone.

The reproducibility of the intraocular pressure response to topical dexamethasone was investigated in 162 persons previously classified as low (NN), intermediate (NG), or high (GG) responders. The concordance of first and second test results was 71% for NN, 74% for NG, and 79% for GG responders, exceeding chance significantly for the NG and GG categories. Quantitative assessment revealed significant correlation of final pressure achieved on first and second tests (r equals .747, P LESS THAN .001). In the course of the study applications of dexamethasone to one eye were noted to have no effect on the intraocular pressure in the contralateral untreated eye, nor did testing of one eye influence the response of the contralateral eye in simultaneous bilateral testing. Using our data to estimate the reproducibility of topical testing in a general population, a value of 73% was obtained. That value was similar to the 65% concordance reported in an identical twin study, suggesting that the limited precision of topical testing accounts for the relatively low concordance found in that study.

Administration, Topical↗

PubMed1974