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Biomedical subjects

M Sears

Publications and source records attributed to M Sears.

70 records · Page 4Linked to original sources
PubMed1979

An interophthalmic communicating artery as explanation for the consensual irritative response of the rabbit eye.

An arterial connection between the two internal ophthalmic arteries in the rabbit was confirmed. The consensual response to ocular injury and its relationship to this interconnecting artery was examined by transecting the interconnecting vessel and creating a monocular injury by anterior chamber paracentesis. In the rabbits of two control groups (those undergoing sham operation without vessel ligation and those undergoing no operation) there was a rise in protein in the aqueous of the uninjured eye. In the rabbits with the communicating artery transected, no such rise in contralateral aqueous protein occurred. It is concluded that in the rabbit this vascular connection can explain the contralateral hyperemia and aqueous protein increase seen after monocular trauma.

Animals↗
PubMed1978

A phase II study of phenesterin (NSC-104469).

Phenesterin was evaluated in 222 patients with two different dosage regimens, one by daily treatment and the other with an intermittent schedule. Toxicity was moderate with both programs. The largest group of patients treated had breast cancer; they experienced a 10% response rate. Of interest was a higher percentage of responses in ovarian cancer (36%). An expanded study of patients with ovarian cancer would be of interest.

Adult↗
PubMed1978

Effects of epinephrine, indomethacin, acetylsalicyclic acid, dexamethasone, and cyclic AMP on the in vitro activity of lysosomal hyaluronidase from the rabbit iris.

The effects of epinephrine, indomethacin, acetylsalicylic acid, dexamethasone, and cyclic AMP on lysosomal hyaluronidase activity in in the rabbit iris were studied in vitro. Indomethacin and acetylsalicylic acid inhibited the lysosomal hyaluronidase activity. Dexamethasone and cyclic AMP (adenosine-3',5'-cyclic monophosphate) had little effect on the enzyme activity. Epinephrine activated the enzyme activity. These drugs had no effect on the activities of either bovine testicular hyaluronidase or rabbit iridial acid phosphatase. The possible role of lysosomal hyaluronidase in the rabbit eye and the drug effects were considered.

Acid Phosphatase↗
PubMed1977

Unilateral gonadectomy does not alter contralateral intraocular pressure in rabbit eyes.

The purpose of this study was to determine whether unilateral gonadectomy caused any change in intraocular pressure. Repeated measurements in 22 male and nine female rabbits after unilateral gonadectomy were made by three different methods of determining intraocular pressure. We were unable to find a decrease in intraocular pressure on the side opposite to the side of the removed gonad, as had been previously reported. Neither were any ipsilateral changes observed. A calibration curve (rabbit) for the applanation pneumatonograph is also presented.

Animals↗
PubMedDate not supplied

The adenylate cyclase receptor complex and aqueous humor formation.

The secretory tissue of the eye, the ciliary processes, contains an enzyme receptor complex, composed of membrane proteins, the catalytic moiety of the enzyme adenylate cyclase, a guanyl nucleotide regulatory protein (or N protein), and other features. The enzyme can be activated by well-known neurohumoral or humoral agents, catecholamines, glycoprotein hormones produced by the hypothalamic pituitary axis, and other related compounds, including placental gonadotropin, organic fluorides, and forskolin, a diterpene. These compounds cause the ciliary epithelia to produce cyclic AMP at an accelerated rate. Cyclic AMP, as a second messenger, causes, either directly or indirectly, a decrease in the net rate of aqueous humor inflow that may be modulated by cofactors. Clinical syndromes fit the experimental data so that an integrated explanation can be given for the reduced intraocular pressure witnessed under certain central nervous system and adrenergic influences. The molecular biology of this concept provides important leads for future investigations that bear directly both upon the regulation of intraocular pressure and upon glaucoma.

Adenylyl Cyclases↗