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Biomedical subjects

J Moolchandani

Publications and source records attributed to J Moolchandani.

7 recordsLinked to original sources
PubMed1991

Effects of adrenergic agents on transepithelial electrical measurements across the isolated iris-ciliary body.

Transmembrane electrical measurements were performed on the isolated rabbit iris-ciliary body to study direct effects of adrenergic drugs on the ciliary epithelium. Alpha-adrenergic agonists (epinephrine, norepinephrine, or phenylephrine) lowered the short-circuit current (SCC) in a dose-dependent fashion relative to which chamber side the drug was added: simultaneous addition to both chambers greater than blood side only greater than aqueous side only. Pretreatment (5 x 10(-5) M) with the non-selective beta-adrenergic antagonist timolol had no effect while the non-selective alpha-adrenergic antagonist, phentolamine, completely prevented the alpha agonist-induced decrease in SCC. The alpha-adrenergic response was mediated by the alpha 1 subtype since prazosin, but not yohimbine, blocked the induced reduction in SCC. The beta-adrenergic agonist isoproterenol caused a dose-dependent decrease in the SCC. The decrease was similar when the drug was added to only the blood side or to both sides of the chamber. Addition to only the aqueous chamber had no effect. Pretreatment with beta-adrenergic antagonists blocked the isoproterenol response: non-selective = selective beta 2 greater than selective beta 1. The isoproterenol-induced decrease in SCC was also blocked by non-selective alpha-adrenergic antagonists. The response was mediated by the alpha 1 subtype since prazosin, but not yohimbine, blocked the isoproterenol response. This suggests that isoproterenol interacted with the alpha 1-adrenergic sensitive pathway in the rabbit ciliary process.

Animals↗
PubMed1990

Eyelid lipoid granuloma following topical ointment application.

Subcutaneous lipogranulomas have been known to occur after injection of lipids for cosmetic or therapeutic reasons. Fibrosis may occur around the granulomas, giving them a lobulated appearance that can clinically mimic a malignancy. Of the few reports of lipogranulomas after the use of topical ointment, none have occurred in the eyelid. We report a case of subconjunctival lipogranulomas after the use of topical ointment whose clinical appearance was suggestive of sebaceous gland carcinoma.

Aged↗
PubMed1989

The ocular hypotensive effects of demeclocycline, tetracycline and other tetracycline derivatives.

Demeclocycline, tetracycline and other tetracycline derivatives lowered intraocular pressure (IOP) in rabbits following intravitreal injection, but the onset of this effect was not evident until 1 or more days after drug administration. Of the drugs tested, demeclocycline was the most active ocular hypotensive agent. Demeclocycline caused a dose-dependent decrease in IOP. The maximum IOP decrease of approximately 12 mm Hg occurred 5 days after intravitreal administration of 0.5 mg, with the effect persisting for over a week. Demeclocycline did not alter tonographically measured aqueous humor outflow facility or episcleral venous pressure. Based on calculated aqueous humor flow rates following 0.2 mg demeclocycline, a 62% decrease in aqueous humor formation occurred 7 days after intravitreal injection. The flow-to-diffusion ratio for ascorbate was reduced 54% 6 days after the intravitreal administration of demeclocycline, a change also consistent with suppression of aqueous humor formation. Anterior chamber aqueous humor protein concentration was increased 6 days after demeclocycline administration. No histologic changes were present in the treated eyes by light microscopy. Intravitreal demeclocycline similarly lowered IOP in cats, with the duration of effect lasting up to 20 days.

Animals↗
PubMed1988

Effects of systemic desmopressin on aqueous humor dynamics in rabbits.

Intravenous desmopressin, a synthetic antidiuretic hormone, resulted in a dose-dependent increase in intraocular pressure (IOP) in rabbits. IOP was increased 3.6 +/- 0.8 mm Hg 6 hr following injection of desmopressin 200 mUnits/kg with the increase lasting over 10 hr. IOP returned to baseline 24 hr after the injection. Systemic blood pressure, plasma osmolarity and arterial blood gases were not altered by desmopressin. The increased IOP was not associated with alterations in measured outflow facility or episcleral venous pressure. Five hours after desmopressin injection, calculated aqueous humor flow was increased approximately 57%. Aqueous humor ascorbate measurements for calculation of flow to diffusion ratios and anterior chamber fluorophotometry also were consistent with an increased rate of aqueous humor formation as the mechanism for the IOP elevation. Desmopressin administration did not increase aqueous humor protein or aqueous humor cyclic AMP concentration. Systemic pretreatment with indomethacin only partially blocked the IOP increase. Systemic pretreatment with demeclocycline completely blocked the desmopressin-induced increase in IOP.

Animals↗
PubMed1987

Central effects of vasoactive intestinal polypeptide on intraocular pressure and body temperature in rabbits.

Administration of vasoactive intestinal polypeptide (VIP) into the rabbit third ventricle via a permanently placed cannula resulted in a dose-dependent increase in intraocular pressure (IOP). IOP was elevated 5.2 mmHg 30 minutes after VIP (10 micrograms/100 microliter) administration. Tonographic outflow facility was not altered by VIP. Thirty minutes after VIP injection into the third ventricle, aqueous humor flow estimated using the Goldmann equation was increased 36% over baseline levels. Intravenous administration of a 10 micrograms dose of VIP did not alter IOP. Systemic blood pressure was unaltered after third ventricle VIP. Systemic pretreatment with the cholinergic antagonist atropine blocked the VIP-induced elevation in IOP. Topical atropine pretreatment had no effect suggesting a central cholinergic mechanism for the VIP-induced increase in IOP. Physiological antagonism of the VIP response was observed after systemic pretreatment with propranolol, phentolamine, or acetazolamide. Body temperature (BT) was significantly elevated in a dose-dependent manner following central VIP administration. Indomethacin pretreatment which had no effect on the IOP response, blocked the VIP temperature response.

Animals↗
PubMed1986

Aqueous production.

The formation of aqueous humour by the ciliary body is a complex process. Active transport of solutes by the ciliary process epithelium is an energy-dependent mechanism that selectively transports substances against an electrochemical gradient across the cell membranes. Water passively follows the active solute transport. In addition to these active transport processes, ultrafiltration contributes to the formation of aqueous humour. The ciliary epithelium contains enzyme systems that function in the production of aqueous humour. The enzymes sodium-potassium-activated adenosine triphosphatase [(Na+:K+)ATPase] and carbonic anhydrase participate in the active transport across this epithelium. Inhibition of these enzymes lowers intraocular pressure (IOP) by decreasing aqueous humour production. the ciliary epithelium contains both alpha- and beta-adrenergic receptors. Electrophysiologic studies on the isolated iris-ciliary body (I-CB) preparation provide a means to study direct effects of the adrenergic agents on transepithelial properties of the ciliary epithelium. This paper will discuss the enzymatic and adrenergic properties of the ciliary epithelium as they relate to active transport and thereby aqueous humour production.

Animals↗