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Biomedical subjects

N Nyman

Publications and source records attributed to N Nyman.

5 recordsLinked to original sources
PubMed1993

The effect of dapiprazole on accommodative amplitude in eyes dilated with 0.5 percent tropicamide.

BACKGROUND: Dapiprazole 0.5 percent (REV-EYES) eyedrops have recently become commercially available in the U.S. to reverse the diagnostic mydriasis produced by various concentrations and combinations of tropicamide and phenylephrine. Although a previous study has shown that dapiprazole increased accommodative amplitude after the administration of tropicamide, no attempt was made to control for differences in pupil size. METHODS: In the present single masked study, the accommodative amplitudes of forty-eight age-matched subjects previously dilated with 0.5% tropicamide were measured through a 3 millimeter artificial pupil following random instillation of dapiprazole in one eye and a placebo drop in the other eye. RESULTS: Area under the curve analysis determined that the magnitude of accommodative response to dapiprazole was significant at p < 0.001 (paired t-test). The McNemar test also showed that the accommodative amplitude was greater in eyes treated with dapiprazole at all observation points (p < 0.005), beginning at 15 mins after the instillation of the test drug. CONCLUSIONS: The results demonstrate that dapiprazole accelerates the return of accommodation independent of pupil size.

Accommodation, Ocular↗
PubMed1990

Effects of dapiprazole on the reversal of pharmacologically induced mydriasis.

The ability of a new alpha-adrenergic antagonist, dapiprazole, to reverse mydriasis produced by phenylephrine 2.5% or 10%, tropicamide 0.5%, and the combination of phenylephrine 2.5% and tropicamide 0.5% was investigated. A double masked crossover design was used to study both efficacy of mydriatic reversal and time course. The safety of administration was evaluated as well. Subjects were optometry students and their spouses. The results demonstrate that dapiprazole is safe and effective for reversing mydriasis produced by both concentrations of phenylephrine, and partially effective in reversing mydriasis in eyes treated with tropicamide 0.5%, alone, or in combination with 2.5% phenylephrine.

Accommodation, Ocular↗
PubMed1989

Retinal arterial macroaneurysms.

Retinal arterial macroaneurysm is a distinct, infrequently occurring fundus sign usually found in older patients with systemic vascular disease. The lesion arises on a main branch of the retinal artery within the first three orders of bifurcation. Visual disturbance is uncommon, although it may occur as a result of vitreous or retinal hemorrhage or macular edema. This paper presents two cases of retinal arterial macroaneurysm and discusses the diagnosis, etiology, and management of this condition.

Aged↗
PubMed1984

Small bowel and liver tissue pO2 and pCO2 during hypovolaemic shock and intravenous vasopressin infusion.

Ten piglets were bled to a mean BP of 60 mm Hg, after which vasopressin was infused for 30 minutes (2.75 mU/kg/min.). Twenty minutes after completion of the vasopressin infusion, the shed blood was retransfused. Small bowel and liver tissue pO2 and pCO2 were continuously monitored. Systemic arterial and portal blood gas analyses and plasma lactate were studied every 30 minutes. Tissue pO2 in both the small bowel and the liver decreased significantly during hypovolaemic shock; a further non-significant decline was noted during vasopressin infusion. Small bowel pCO2 increased, but liver pCO2 remained unchanged. Plasma lactate increased significantly during hypovolaemia, and vasopressin caused a further increase to a level three times the rest period level. These findings indicate that vasopressin infused during hypovolaemia may increase the risk of hypoxic intestinal lesions and impair liver function.

Animals↗