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Biomedical subjects

L Cantor

Publications and source records attributed to L Cantor.

9 recordsLinked to original sources
PubMed2000

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients.

OBJECTIVE: To determine whether dosages of a selective beta-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation. DESIGN: Counterbalanced crossover, with open-label use of medications. PARTICIPANTS: Nine persons with normal-tension glaucoma (NTG). INTERVENTION: After a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics. MAIN OUTCOME MEASURES: At baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging. RESULTS: Betaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks. CONCLUSIONS: Although both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

Adrenergic beta-Antagonists↗
PubMed1998

The effect of mitomycin C on Molteno implant surgery: a 1-year randomized, masked, prospective study.

PURPOSE: The authors assess whether adjunctive mitomycin C improves Molteno tube shunt surgery in terms of intraocular pressure (IOP), visual acuity, and complication rates. PATIENTS AND METHODS: Twenty-five eyes of twenty-five consecutive patients undergoing double-plate Molteno implant surgery were randomized to receive either mitomycin C (MMC) 0.4 mg/mL for 2 minutes or a control balanced salt solution in a masked, prospective study. Intraocular pressure, visual acuity, and complications were recorded 1 week and 1, 3, 6, and 12 months after surgery. A repeated measures analysis of variance (ANOVA) model was used to test the overall effect of the drug on IOP and percent change from preoperative IOP. RESULTS: Thirteen eyes received balanced salt solution and 12 eyes received MMC. There was no difference between the groups with respect to age, preoperative IOP, log mean angle of resolution (LogMar) visual acuity, or number of preoperative medications. Except for week 1, there were no differences between the groups at any of the clinic visits with respect to IOP and percent change from baseline IOP. Analysis of the visual acuity (LogMar) showed reduction in vision for both groups. Complications were similar in each group, as were number of postoperative hypotensive agents required. CONCLUSIONS: Adjunct MMC does not demonstrate a significant difference in outcomes compared with placebo in pressure-ridged Molteno implant surgery. Results of this study are limited by a small number of patients in each group and a fixed dose of MMC.

Adult↗
PubMed1992

Aqueous shunts. Molteno versus Schocket.

The authors conducted a multicenter, randomized, controlled trial to test whether the Schocket shunt with a larger shunt reservoir surface area would provide a lower final intraocular pressure than the double-plate Molteno implant. However, the Molteno implant produced a statistically lower intraocular pressure at 6 months compared with the Schocket shunt. Postoperative visual acuity, glaucoma medications, and complications were not statistically different.

Aqueous Humor↗
PubMed1982

The effectiveness of progressive relaxation in chronic hemodialysis patients.

An experimental group of 38 patients on chronic hemodialysis were presented a 30-min, self-instructional, color videotape on progressive relaxation (PR) exercises; and a control group of 23 patients viewed a neutral videotape. Both groups were given the State-Trait Anxiety Inventory while on the dialysis machine, before and after the actual viewing. The experimental group significantly reduced its state anxiety level while the control group remained the same. Patients who reported higher levels of state anxiety and experienced tension more frequently tended to achieve the greater benefit from the program. It is postulated that PR can be a useful resource to overcome the sometimes severe anxiety related to the stresses of chronic hemodialysis.

Adult↗
PubMed1972

Globin messenger RNA activity in erythroid precursor cells and the effect of erythropoietin.

Cell populations enriched for erythroid precursor cells were fractionated from 13-day fetal-mouse livers by a method of immune hemolysis. These preparations of precursors, contaminated by less than 7% hemoglobinized erythroblasts, synthesize globin at a rate less than 6% that of the unfractionated liver erythroid cell population. RNA was isolated from these precursor cells and assayed for globin mRNA activity in a cell-free system from Krebs ascites tumor. The 6-16S RNA fraction from precursor cells has less than 5% of the globin mRNA activity of RNA isolated from unfractionated populations. Precursor cells incubated with erythropoietin show an increment in the rate of synthesis of globin only after 5-10 hr of incubation. After 10 hr of culture with this hormone, precursor cells show a 6- to 10-fold increase in globin mRNA activity. These results suggest that the precursor cells of hepatic erythropoiesis, responsive to erythropoietin, do not contain globin mRNA in a biologically active form. Erythropoietin-induced differentiation of these cells to erythroblasts is associated with an increase in globin mRNA.

Animals↗
PubMedDate not supplied

Prospective comparison of the Heine retinometer with the Mentor Guyton-Minkowski potential acuity meter for the assessment of potential visual acuity before cataract surgery.

Various techniques and devices have been developed to aid in the assessment of potential visual acuity prior to cataract surgery. We report a prospective comparison of two such assessments, one made using a new instrument, the hand-held Heine retinometer (HR) (Heine Instruments, Germany), and the other using the Mentor Guyton-Minkowski potential acuity meter (PAM) (Mentor, Inc, Norwell, Mass). A total of 37 eyes were assessed using both instruments just before cataract surgery. Three eyes were excluded from analysis due to postoperative complications affecting visual acuity that could not have been predicted with either instrument. The false-negative rate was 44% for the PAM and 32% for the HR. There were no false-positive results with either instrument. Neither instrument was particularly accurate in predicting actual final visual acuity (r2 = 0.290 and 0.144 for the PAM and HR, respectively). The HR was deemed easier to use.

Cataract↗