Evaluation of travoprost as adjunctive therapy in patients with uncontrolled intraocular pressure while using timolol 0.5%.

PURPOSE: To evaluate the intraocular pressure-lowering efficacy and safety of travoprost 0.0015% and 0.004%, dosed daily in the evening compared with vehicle, in patients with open-angle glaucoma or ocular hypertension, whose intraocular pressure was not adequately controlled on timolol 0.5% twice daily (twice daily). METHODS: Subjects who qualified at screening began a run-in period dosing timolol twice daily for 3 weeks. If the subjects had an intraocular pressure of 24 to 36 mm Hg at 8 AM and 21 to 36 mm Hg at 10 AM and 4 pm in at least one eye on timolol, they were randomized to one of two concentrations of travoprost (0.0015% or 0.004%) or vehicle solution every day and were followed for 6 months. Four hundred twenty-six subjects were randomized. The mean intraocular pressure at 8 AM, 10 AM, and 4 PM in the patient's eye with the higher intraocular pressure was used for the analysis. RESULTS: Mean baseline values (25 mm Hg) for subjects at eligibility (while maintained on timolol) were not significantly different (P <.0001) among the treatment groups. The intraocular pressure was lowered an additional -5.7 to -7.2 mm Hg and -5.1 to -6.7 mm Hg in the travoprost 0.004% and 0.0015% concentrations, respectively. These changes were significantly (P < or =.0001) different from the vehicle group (-1.3 to -2.8 mm Hg). The intraocular pressure range on treatment at all visit times over the 6-month treatment period ranged from 17.9 to 19.2 mm Hg for travoprost 0.004% and 18.3 to 20.1 mm Hg for travoprost 0.0015% compared with 22.4 to 24.1 mm Hg for vehicle. Average hyperemia scores ranged from trace to mild (mean 0.5 on a scale of 0 = none/trace; 1= mild; 2 = moderate; 3 = severe) for all treatment groups. No iris pigmentation changes were observed in any patient during this study. There were no clinically or statistically significant changes from baseline in visual acuity, ocular cells and flare, fundus parameter, cup-to-disk ratio and visual field between the treatment groups. There were no serious adverse events reported for any treatment group. CONCLUSIONS: Travoprost produced clinically relevant and statistically significant additional intraocular pressure reductions from baseline when used adjunctively with timolol in subjects with open-angle glaucoma or ocular hypertension.

Long-term intraocular pressure-lowering efficacy and safety of timolol maleate gel-forming solution 0.5% compared with Timoptic XE 0.5% in a 12-month study.

PURPOSE: To evaluate the long-term intraocular pressure-lowering efficacy and safety of timolol maleate gel-forming solution 0.5% (Timolol GFS 0.5%, Alcon Research Ltd, Fort Worth, Texas) compared with Timoptic XE 0.5% (Merck, Inc, West Point, Pennsylvania) in patients with open-angle glaucoma or ocular hypertension. METHODS: Two hundred forty-one patients with open-angle glaucoma or ocular hypertension, who had intraocular pressure between 22 and 36 mm Hg in at least one eye, were randomly assigned in a 2:1 ratio to receive either Timolol GFS 0.5% once daily or Timoptic XE 0.5% once daily, in a 12-month randomized, multicenter, double-masked, prospective study. The primary efficacy variable was mean trough intraocular pressure measured at 8:00 AM, approximately 24 hours after dosing. RESULTS: The Timolol GFS 0.5% group produced significant trough intraocular pressure reductions from a baseline of 4.5 to 5.2 mm Hg (P =.0001), compared with reductions of 4.1 to 5. 3 mm Hg (P =.0001) in the Timoptic XE 0.5% group. The difference in mean intraocular pressure between the two treatments was 0.9 mm Hg or less, and the upper 95% confidence limit between groups was 0.92 mm Hg or less at all time points, demonstrating both clinical and statistical equivalence. A similar percentage of patients in the Timolol GFS 0.5% group (71%) and Timoptic XE group (72%) had clinically relevant reductions in intraocular pressure. There was no significant difference in the safety profiles of the two treatments. CONCLUSION: Both treatments were clinically effective in lowering intraocular pressure and maintaining the reductions over long-term use. Timolol GFS 0.5% is a safe and effective therapy for open-angle glaucoma or ocular hypertension and is both clinically and statistically equivalent to Timoptic XE 0.5% in reducing intraocular pressure.

Ocular comfort of brinzolamide 1.0% ophthalmic suspension compared with dorzolamide 2.0% ophthalmic solution: results from two multicenter comfort studies. Brinzolamide Comfort Study Group.

Two independent, prospective, multicenter, double-masked, parallel group trials were conducted to compare the ocular comfort of brinzolamide 1.0% administered three times daily (t.i.d.) with t.i.d.-dosed dorzolamide 2.0% in patients with primary open-angle glaucoma or ocular hypertension. Patients were randomized to one of two treatment groups, receiving either brinzolamide 1.0% t.i.d. or dorzolamide 2.0% t.i.d. for 1 week. On the last day of dosing, patients received one drop of masked medication in both eyes, and ocular discomfort (burning or stinging) was evaluated by means of a 4-unit ocular discomfort scale. The incidence and extent of ocular discomfort across both treatment groups were analyzed. The results from both studies were confirmatory and demonstrated that the ocular discomfort score for brinzolamide 1.0% was 1.3 units lower than the score for dorzolamide 2.0%, which was both statistically significant and clinically relevant. In addition, a statistically significantly greater percentage of patients reported no ocular discomfort with brinzolamide 1.0% compared with dorzolamide. A greater percentage of patients receiving dorzolamide 2.0% also reported mild, moderate, severe, and very severe ocular discomfort compared with those treated with brinzolamide 1.0%. The most frequent ocular adverse event reported in the brinzolamide group was transient blurred vision, which ranged from 20% to 25%. Overall, adverse events associated with brinzolamide 1.0% and dorzolamide 2.0% were nonserious, were usually mild, and resolved without treatment. The findings of each study independently demonstrated that brinzolamide 1.0% was significantly more comfortable than dorzolamide 2.0% when instilled in the eye.

Dose-response evaluation of the ocular hypotensive effect of brinzolamide ophthalmic suspension (Azopt). Brinzolamide Dose-Response Study Group.

Brinzolamide is a novel carbonic anhydrase inhibitor that elicits an ocular hypotensive effect when instilled topically. A multicenter, double-masked, placebo-controlled, parallel trial was conducted to evaluate the optimal intraocular pressure (IOP)-lowering concentration and ocular tolerability of topically administered brinzolamide (0.3%, 1%, 2%, and 3%) in patients with primary, open-angle glaucoma or ocular hypertension. After a washout phase, patients were administered brinzolamide or placebo twice daily for 2 weeks. The IOP was measured on days 8 and 15 at 8:00 A.M., and then 2, 4, 8, and 12 hours after dosing, and these measurements were compared with IOP values obtained at the corresponding times during an off-therapy diurnal baseline. All concentrations of brinzolamide produced significantly greater (P<0.005) mean percent IOP reductions and mean IOP reductions compared with placebo. Mean percent IOP changes (mean IOP changes) from baseline for brinzolamide 0.3%, 1%, 2%, and 3% were -11.3% (-3.0 mm Hg), -16.1% (-4.3 mm Hg), -16.1% (-4.4 mm Hg), and -15.4% (-4.2 mm Hg), respectively, when pooled over visit and visit time. Comparisons between concentrations demonstrated that the mean percent IOP reduction for brinzolamide 1.0% was significantly greater than that for the 0.3% concentration (P<0.03), with no difference in efficacy between the 1%, 2%, and 3% concentrations. The incidence of adverse events was dose-dependent, and those related to therapy were usually mild and resolved without treatment. Blurred vision, ocular discomfort, and abnormal taste were the most frequently reported adverse events. Based on these findings, the optimal IOP-lowering concentration of brinzolamide was 1%. When administered twice daily, brinzolamide 1% was well tolerated by patients with primary open-angle glaucoma or ocular hypertension.

Clinical efficacy and safety of brinzolamide (Azopt), a new topical carbonic anhydrase inhibitor for primary open-angle glaucoma and ocular hypertension. Brinzolamide Primary Therapy Study Group.

PURPOSE: To determine the intraocular pressure-lowering efficacy and safety of brinzolamide 1.0%, compared with dorzolamide 2.0% and timolol 0.5%. METHODS: A multicenter, double-masked, prospective, parallel-group study was conducted to compare brinzolamide 1.0%, administered two and three times a day, dorzolamide 2.0% three times a day, and timolol 0.5% twice a day in 572 patients with primary open-angle glaucoma or ocular hypertension. The primary end point was diurnally corrected intraocular pressure reduction from baseline, evaluated at both peak and trough times during a 3-month period. RESULTS: Mean intraocular pressure changes after twice daily (-3.8 to -5.7 mm Hg) and three times daily (-4.2 to -5.6 mm Hg) dosing with brinzolamide 1.0% were statistically equivalent (confidence limit < or = 1.5 mm Hg) to each other and also to dorzolamide 2.0% three times a day (-4.3 to -5.9 mm Hg). The range of intraocular pressure change with timolol 0.5% twice daily was -5.2 to -6.3 mm Hg. Clinically relevant intraocular pressure changes (reduction > or = 5 mm Hg or intraocular pressure < or = 21 mm Hg) were observed in up to 75.7% of patients taking brinzolamide twice daily and in up to 80.1% taking brinzolamide three times daily. Treatment with brinzolamide 1.0% was safe, comfortable, and well tolerated. The incidence of ocular discomfort (burning and stinging) on instillation of brinzolamide (twice daily, 1.8%; three times daily, 3.0%) was significantly less (P = .000) compared with treatment with dorzolamide (16.4%). CONCLUSIONS: Brinzolamide 1.0% produced clinically relevant intraocular pressure reductions in substantial numbers of patients. Brinzolamide's effectiveness equaled that of dorzolamide 2.0% and it produced less ocular discomfort (burning and stinging) on instillation.

Decreased sodium-potassium pump activity in isolated hypertrophied feline ventricular myocytes.

The activity of the Na-K pump was assessed in normal and hypertrophied isolated feline myocytes by measuring ouabain-sensitive 42-K uptake. Right ventricular hypertrophy was produced in feline myocardium by placing a constricting band around the pulmonary artery of adult cats. High yields of calcium tolerant myocytes were isolated from the right and left ventricle of banded and sham operated animals. Intracellular sodium (Na) and potassium (K) concentrations (mM) were not significantly different (P greater than 0.5) in normal (Na: 13.2; K: 133.4) and hypertrophied (Na: 12.3; K: 127.5) myocytes. Morphometric analysis demonstrated a 26% increase in width and a 42% increase in volume of hypertrophied myocytes, however, the sarcomere length (1.9 mu) was not different in both cell types. The rate constant (k, min-1) describing 42-K uptake and the calculated total K influx (I, pmol/cm2/sec) were not significantly different (P greater than 0.5) in normal (k = 0.059; I = 15.9) and hypertrophied (k = 0.062; I = 15.3) cells. Ouabain-sensitive (active) K influx, a measure of Na-K pump activity, was maximally inhibited at 10(-4)M ouabain in both cell types. At this concentration, ouabain-sensitive K uptake was decreased 23.5% in hypertrophied myocytes compared to control. The decrease in active K influx may be due to a decrease in the activity of the Na-K ATPase and/or to a reduction in the passive movement of sodium and potassium down their electrochemical gradients.

Transmembrane potassium fluxes in isolated feline ventricular myocytes.

Radioactive tracer (42K) flux techniques were used to determine transmembrane K+ influx and efflux in isolated cardiac myocytes. Ca2+-tolerant adult feline ventricular myocytes were isolated by retrograde perfusion of the coronary arteries with a collagenase-containing solution. The isolated cells had intracellular Na+ (17.2 +/- 0.2 mM) and K+ (135.0 +/- 3.9 mM) concentrations that were stable over time. 42K influx and efflux were both described by a single exponential function. The rate constant describing 42K influx was 5.86 +/- 0.40 X 10(-2) min-1, and the calculated total K+ influx was 18.4 +/- 1.6 pmol X cm-2 X s-1. Ouabain produced a dose-dependent decrease in K+ influx with maximal inhibition at 10(-4) M. In the presence of 10(-4) M ouabain, total K+ influx was resolved into both active (ouabain-sensitive 12.2 pmol X cm-2 X s-1) and passive (ouabain-insensitive 6.2) components. The rate constant describing 42K efflux was 6.46 +/- 0.50 X 10(-2) min-1, and the calculated total K+ efflux was 22.0 +/- 1.5 pmol X cm-2 X s-1. K+ efflux was not significantly altered (P greater than 0.5) in the presence of 10(-4) M ouabain. The absolute magnitudes of total K+ influx and efflux were not significantly different (P greater than 0.1), thus suggesting that the cells were in a steady state with respect to K+. These studies demonstrate that transmembrane tracer kinetics and K+ fluxes were readily described using isolated adult cardiac myocytes and that both the active and passive components of these unidirectional fluxes were identified in the presence of ouabain.

Passive membrane properties of isolated feline ventricular myocytes.

Membrane properties of adult mammalian cardiac muscle are difficult to define mainly because of experimental complications arising from complex packing of myocytes in the tissue matrix. Isolated feline myocytes were used in the present study to avoid these complications. The objectives of this study were to define the functional relationship between passive unidirectional transmembrane potassium (K+) fluxes, membrane permeability to K+ (PK), and membrane K+ (Ko) dependency of this relationship. Passive (ouabain-insensitive) components of unidirectional K+ fluxes were measured with 42K, and membrane potential (Em) and membrane (slope) conductance (gm) were measured with electrophysiological techniques. Myocytes studied in solutions with 5 mM K+o had normal resting potentials (-81 +/- 1 mV). The input resistance and membrane time constant were 2.72 +/- 0.47 X 10(-7) omega and 7.01 +/- 1.0 ms, respectively. When K+o was lowered Em hyperpolarized, input resistance (Ri) increased, and K+ fluxes decreased. When K+o was increased Em depolarized, Ri decreased, and K+ fluxes increased. These data were combined to determine whether K+ fluxes obey the independence principle and to calculate PK and gK. The results obtained support the idea that 1) unidirectional K+ fluxes do not obey the independence principle, 2) PK is much greater than the membrane permeability to other ions, and 3) the gK calculated from passive K+ fluxes was similar to the gm measured electrically (at all K+o's tested).

Isolation and morphology of calcium-tolerant feline ventricular myocytes.

A technique has been developed for isolating a high yield of Ca2+-tolerant rod-shaped myocytes from the right and left ventricles of cat myocardial tissue. Myocytes were prepared by retrograde perfusion of the coronary arteries via the aorta with a nominally Ca2+-free (20-30 microM) modified Krebs-Henseleit buffer containing 0.12% collagenase. After exposure to physiological levels of Ca2+ (1-2.5 mM), the cells retained rod-shaped morphology, exhibited clear cross striations, and excluded the dye trypan blue (0.4%). Initial percents of viable Ca2+-tolerant rod-shaped cells were 58.6 +/- 3.4 (SE) and 51.8 +/- 3.5 for right and left ventricular cells, respectively. Viability studies demonstrated that these values decreased approximately 10% at the conclusion of a 2-h incubation in 1 mM Ca2+. The total numbers of rod-shaped myocytes obtained were 4.48 X 10(7) and 3.89 X 10(7) in nominal (8-10 microM) and 1 mM Ca2+-containing buffer, respectively. A total of 3.44 +/- 0.40 X 10(6) rod-shaped Ca2+-tolerant myocytes was initially isolated per gram of tissue wet weight. Measurements of cell length, width, and sarcomere length demonstrated no significant differences between right and left ventricular cells suspended in nominal (8-10 microM) and 1 mM Ca2+-containing buffer. No significant difference was found in the percent of binucleate cells when right and left ventricular myocytes were compared. These results demonstrate that a stable population of Ca2+-tolerant myocytes with similar morphological characteristics can be isolated from the right and left ventricles of cat myocardium.

Effects of alcohols upon pacemaker activity in neurons of Aplysia californica.

1. Alcohols have been used as pharmacological tools to probe the nature of action-potential gates and channels. In this study, we examine the effects of alcohols upon activity patterns in Aplysia neurons. 2. Ethanol at concentrations of 0.4-0.6 M induces bursting pacemaker activity (BPA) in previously silent cells. The same effect is produced with 40-60 mM concentrations of butanol, suggesting that this induction is not due to osmotic effects. 3. Voltage-clamp measurements indicate that the induction of BPA is accompanied by the appearance of a negative-slope resistance (NSR) region in the steady-state current-voltage relationship of the cell. The induction of BPA and a NSR region in silent cells is antagonized by lowered temperatures. 4. Ethanol concentrations which produce BPA and a NSR region in silent cells abolish both of these normally present characteristics in endogenous bursters. This suggests that whatever membrane components are moved into optimal configuration for the expression of BPA in silent cells are shifted out of optimal configuration in endogenous bursters, by similar ethanol concentrations.

Aggregation properties of the acetylcholinesterase from the central nervous system of Manduca sexta.

The CNS of the tobacco hornworm, Manduca sexta, provides a rich source of true acetylcholinesterase (AChE, acetylcholine, hydrolase, EC 3.1.1.7). Optimal extraction of the enzyme was obtained with a nonionic detergent at high ionic strength (1% Triton X-100, 0.5 M NaCl). Velocity sedimentation of the Triton + salt-extracted enzyme demonstrated a single peak whose sedimentation coefficient was dependent upon the enzyme concentration layered on top of the gradient. When more than 20 units were applied to the gradient, a sedimentation coefficient of 8.6 S (205,000) was obtained, and extrapolation to zero units yielded a 5.7 S (110,500) species. Sedimentation in the absence of detergents (1.0 M NaCl or 10 mM phosphate buffer, pH 7.4) yielded pelleted enzyme and species with mean values of 18.6 S (650,000) and 17.5 S (600,000), respectively. The detergent-extracted enzyme also demonstrated a concentration-dependent size in gel filtration experiments. When less than 300 units were applied to the column, a single species was recovered, with a molecular radius of 40.15 +/- 2.08 A (108,000) or 43.4 +/- 2.38 A (117,000) calculated by different methods. If the sample contained 300 to 1,300 units, two species were observed, with molecular radii of 40.15 +/- 2.08 A or 43.4 +/- 2.38 A and 78.4 +/- 3.94 A (319,000) or 80.25 +/- 3.01 A (326,000). Velocity sedimentation and gel filtration of AChE have demonstrated that the enzyme has a minimum molecular weight of approximately 110,000 and also exists as higher-molecular-weight aggregates of this value.