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Biomedical subjects

M Blumenthal

Publications and source records attributed to M Blumenthal.

At least 19 recordsLinked to original sources
PubMed1999

Digital assessment of the epicardial electrocardiogram: novel methodology for a core laboratory for clinical studies.

BACKGROUND: The epicardial electrocardiogram (ECG) is a sensitive marker for cardiac ischemia and has been used as a measure of ischemia in clinical trials. We sought to examine the utility of a central ECG laboratory for determining ischemic-type ST-segment shifts from epicardial ECG recordings obtained from multiple clinical sites. HYPOTHESIS: We speculated that an operator-assisted digital ECG core laboratory is feasible, reliable, and efficient, with the ability for rapid and accurate interpretation of the epicardial ECG. METHODS: The epicardial ECG was recorded via an angioplasty guidewire placed in a coronary artery of a patient undergoing angioplasty. Site investigators visually determined the time-to-onset of 0.1 and 0.3 mm ST-segment elevation, and the maximal ST-segment elevation during balloon inflation, and then compared the measurements with those made at an operator-assisted digital ECG core laboratory. RESULTS: Agreement between the two methods occurred in 78% of the time-to-onset measurements, but in only 39% of the maximal ST-segment measurements. Overall, the visual measurements of the clinical investigators of time-to-onset differed from the digital core laboratory by 11.8 +/- 11.6 s for 0.1 mV, and 15.8 +/- 20.6 s for 0.3 mV. Recorded maximal ST-segment shifts differed by a mean of 0.47 +/- 0.69 mV. CONCLUSION: The magnitude of inconsistency between the ECG core laboratory results using an operator-assisted digital method and the interpretations of clinical investigators using manual caliper-type analysis was surprisingly large. These results support the need for an ECG core laboratory in clinical trials where ECG ST-segment shifts are used as a response variable.

Adult↗
PubMed1999

Patterns of late corneal scarring after photorefractive keratectomy in high and severe myopia.

OBJECTIVE: To study the correlation between scarring 1 year after photorefractive keratectomy (PRK), final refraction, and degree of myopia. DESIGN: A retrospective, noncomparative case series. PARTICIPANTS: One hundred twenty eyes of 78 patients underwent PRK for high and severe myopia. Thirty-nine eyes had a pre-PRK spherical equivalent (SE) between -9.5 and -18.25 diopters (D) (severe myopia). Eighty-one eyes had a pre-PRK SE between -6.25 and -9.25 D (high myopia). Follow-up time ranged between 12 and 37 months with a mean of 18.2 months. INTERVENTION: Multizone PRK with the VISX 20/20 excimer laser. MAIN OUTCOME MEASURES: Corneal scarring, final best-corrected visual acuity (BCVA), and refraction. RESULTS: There were 71.7% of eyes with severe myopia and 60.5% of eyes with high myopia found to have any pattern of stromal scarring, which was classified as focal, semiannular, annular, and discoid. Discoid scars were rare (6.6%) and found in 12.8% of severe myopic eyes compared to 3.7% of high myopic eyes. Only 50% of the eyes with a discoid scar achieved final BCVA between 6/6 and 6/9 compared to 81.6% of the eyes with a clear cornea. The severe myopic eyes with a discoid scar had the highest level of final undercorrection (-5.0 D) compared to a maximum of -1.5 D in the high myopia group. The severe myopic eyes with a discoid scar had a higher number of retreatments (4 of 5) compared to the high myopia group (1 of 3). Other types of scars were less clinically significant. CONCLUSIONS: Photorefractive keratectomy was efficient in the correction of high myopia but less so in severe myopia, in which discoid scarring was more frequent and more clinically significant, being associated with significant regression. Other types of scarring were less clinically significant.

Adolescent↗
PubMed1999

Effect of expandable full-size intraocular lenses on lens centration and capsule opacification in rabbits.

PURPOSE: To study the effects of expandable, hydrogel, full-size lenses (FSLs) on lens centration and posterior capsule opacification (PCO) in the rabbit model. SETTING: Center for intraocular Lens Research, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Small FSLs designed for human eyes were implanted unilaterally in 20 rabbit eyes. Lens centration and PCO in these eyes were compared with those in eyes with conventional poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) or aphakia in the fellow eyes. In a second experiment, medium-size or large FSLs designed for rabbit eyes were implanted in 20 rabbit eyes and the results compared with those in eyes with conventional PMMA IOLs. Slitlamp examination of all eyes was performed regularly, after enucleation, gross inspection and microscopic studies were performed. RESULTS: Decentration of FSLs occurred in the presence of an anterior capsule tear or very large capsulorhexis. Posterior capsule opacification developed only at sites where the implanted lens was not in contact with the capsule. Aphakic eyes and looped IOLs developed Soemmering's rings peripherally. In eyes with small FSLs, PCO developed between the lens and the center of the posterior capsule, whereas in eyes with large FSLs, only small amounts of central PCO developed. Retained high-viscosity viscoelastic material had no effect on PCO development. CONCLUSIONS: Complete refilling of the capsular bag by a full-size IOL was associated with excellent centration and only a small degree of PCO. Elastic lenses may thus serve as a starting point for the development of an artificial lens with accommodative function.

Animals↗
PubMed1998

An automated method for determination of antibody affinity distribution functions with nanogram quantities.

We have developed a method to determine the binding affinity distribution functions (the probability density function for affinity constants will be referred to as affinity distribution throughout the text) for human serum antigen specific IgE for their respective allergens. This fully automated method, based on the Access technology of Sanofi Diagnostics Pasteur, is a highly sensitive two-step sandwich immunoassay requiring only nanogram quantities of antibodies. Allergen-antibody binding isotherms can be determined covering a range of 5 magnitudes of ligand (allergen) concentration. An affinity distribution function, describing the polyclonal nature of the antibody response, can be calculated from the binding isotherm. The validity of the method is assessed using mAbs against the purified allergen Der p 1. The resolving power and sensitivity of the method are demonstrated using selected sera from donors with high and low levels of specific IgE for these allergens. We are able to show that heterogeneous IgE populations can be determined using 100 microl of sera containing 150 pg of specific IgE per ml. Overall, the range of affinities that can be determined by this method is 1 x 10(6)-1 x 10(11) M(-1).

Allergens↗
PubMed1998

Experimental studies on viscofluids for intraocular surgery.

PURPOSE: To investigate the feasibility and efficacy of using diluted viscofluids during intraocular surgery. SETTING: Laboratory for Intraocular Microsurgery and Implants, Goldschleger Eye Research Institute, and the Sackler School of Medicine, Tel-Hashomer, Israel. METHODS: Diluted hyaluronic acid (0.06 to 0.12%) in balanced salt solutions were irrigated through the phacoemulsification machine or a separate irrigation line (i.e., anterior chamber maintainer). Irrigation was facilitated by increasing the atmospheric pressure in the bottle using compressed air. Experimental surgery was done in rabbit eyes. RESULTS: A viscous fluid could be irrigated at any practical rate by increasing the height of the bottle, increasing the atmospheric pressure within the bottle, or both. Experimental surgeries showed that viscofluids maintained intraocular pressure and anterior chamber volume, allowed safe intraocular manipulations, reduced turbulence in the anterior chamber, and probably provided tissue protection. CONCLUSION: Viscofluids irrigated using a high-pressure system combined the advantages of continuous irrigation of fluids and the protective qualities of viscoelastics in this rabbit eye study.

Animals↗
PubMed1998

Three year results of photoastigmatic refractive keratectomy for mild and atypical keratoconus.

PURPOSE: To evaluate the long-term effect of photoastigmatic refractive keratectomy (PARK) on mild keratoconus. SETTING: Laser Unit, Ein Tal Eye Center, Tel Aviv, Israel. METHODS: Eight eyes of 6 patients with stable compound myopic astigmatism and topography features of keratoconus were treated with a VISX Twenty-Twenty excimer laser. The laser beam slit width ranged between 4.8 and 5.0 mm according to the degree of cylinder. Preoperative slitlamp examination did not reveal significant thinning, ectasia, or scarring. Astigmatism ranged between -2.00 and -7.50 diopters and follow-up, between 36 and 48 months. RESULTS: In 7 of 8 eyes, uncorrected visual acuity (UCVA) before PARK ranged between 6/30 and finger counting. After PARK, it ranged between 6/9(-) and 6/15, and patients could manage in most of their daily activities without using spectacles. In 2 eyes, the final UCVA was 6/15(-) and 6/15. In 1 eye, treatment failed to improve UCVA and corneal topography revealed progression of the keratoconus. CONCLUSIONS: Photoastigmatic keratectomy was partially effective in eyes with mild stable keratoconus. However, the long-term results may be altered by progression of corneal thinning and ecstatic disease. In addition to the mild nature of the keratoconus, this is a small series and further studies are needed to confirm these results.

Adult↗
PubMed1997

Excimer phototherapeutic keratectomy for corneal subepithelial cryoglobulin deposits.

A 64-year-old man with a history of cryoglobulinemia and repeated scraping of immunoglobulin deposits from both superficial corneas presented with gradual decrease in vision and progressive hyperopia caused by circumferential redeposition of the cryoglobulins in his corneas. He had debridment of the deposits combined with phototherapeutic keratectomy to smooth the corneal surface. Visual acuity and reading capacity markedly improved, and hyperopia regressed by 5.75 diopters (D) in the right eye and 5.25 D in the left. Follow-up was 3 years.

Corneal Diseases↗
PubMed1997

Preventing expulsive hemorrhage using an anterior chamber maintainer to eliminate hypotony.

We describe a method in which constant infusion inflow through an anterior chamber maintainer (ACM) is used to maintain positive intraocular pressure (IOP) during cataract extraction through a self-sealing tunnel incision. A retrospective review of patient records showed that the difference in the incidence of intraoperative suprachoroidal hemorrhage was significantly greater in eyes in which IOP was not constant throughout surgery than in eyes in which IOP was maintained using the ACM system.

Anterior Chamber↗
PubMed1997

Treatment of congestive heart failure: experience with fosinopril.

The prevalence of congestive heart failure (CHF), a debilitating condition associated with impaired quality of life and markedly shortened life expectancy, is increasing. The goals of therapy for CHF are reducing symptoms, improving functional capacity, and slowing the progression of the condition. In most cases, this is best achieved with a combination of diuretic and vasodilator therapy. Angiotensin-converting enzyme (ACE) inhibitors have several advantages over other vasodilatory agents and are becoming widely used for treating CHF. The most recently introduced ACE inhibitor, fosinopril, is at least as effective as enalapril, and its dual and compensatory route of excretion is particularly advantageous in patients with renal insufficiency. Fosinopril may also have particular benefits in the prevention of CHF, as it has beneficial effects on cardiac function that may help delay the onset of overt cardiac failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Combined PRK and PTK in myopic patients with recurrent corneal erosion.

AIM: To study the results of combined photorefractive keratectomy (PRK) and phototherapeutic keratectomy (PTK) in myopic patients with recalcitrant recurrent corneal erosion. METHODS: PRK was performed in 16 eyes with the Visx 20/20 excimer laser at a central 6.0 mm zone, following total epithelial scraping. Subsequently, confluent 3.0 mm zones of PTK were ablated at a depth of 6.0 microns, surrounding the zone of PRK. The follow up period ranged from 26 to 42 months. RESULTS: Complete alleviation of symptoms was demonstrated and there was no recurrence of corneal erosion. Visual acuity (VA) improved slowly following treatment, with a final uncorrected VA ranging between 6/9 and 6/12. A final myopic spherical equivalent < or = -1.0 D was found in 14 out of 16 eyes. CONCLUSIONS: A combination of PRK and PTK is effective in the alleviation of symptoms and prevention of recurrences of corneal erosion. It is suggested that recalcitrant recurrent corneal erosion is a diffuse disease, although it often manifests as a local problem, and therefore extensive excimer laser ablation is required to prevent recurrence and to alleviate symptoms completely.

Adult↗
PubMed1997

Performing peripheral iridectomy via a scleral tunnel incision: a new approach.

A peripheral iridectomy (PI) is sometimes difficult to perform through a sclero-corneal tunnel. This study evaluated the effectiveness and safety of a newly proposed technique for performing a PI. The results showed that a PI can be easily performed through a sclero-corneal tunnel, employing this technique.

Anterior Chamber↗
PubMed1996

Fluticasone propionate aqueous nasal spray compared with terfenadine tablets in the treatment of seasonal allergic rhinitis.

BACKGROUND: Comparative studies with topical corticosteroids and antihistamines for treatment of allergic rhinitis have not always demonstrated clear distinctions between the two on the basis of therapeutic efficacy. OBJECTIVE: This study was designed to compare the efficacy and tolerability of fluticasone propionate aqueous nasal spray with those of terfenadine in the treatment of seasonal allergic rhinitis. METHODS: Three hundred forty-eight patients with allergic rhinitis were given fluticasone propionate aqueous nasal spray (200 micrograms once daily), terfenadine tablets (60 mg twice daily), or placebo for 4 weeks in a multicenter, randomized, double-blind, double-dummy, parallel-group study. RESULTS: Clinician-rated total nasal symptom scores after 1, 2, 3, and 4 weeks of therapy and patient-rated total nasal symptom scores throughout treatment were significantly (p <0.05) lower in the fluticasone propionate group compared with the terfenadine group or the placebo group. Terfenadine was not statistically different from placebo on the basis of clinician-related nasal symptom scores, except for sneezing. Total nasal airflow, measured by rhinomanometry, significantly (p <0.05) improved in the fluticasone propionate group compared with the terfenadine group or the placebo group. More fluticasone propionate-treated patients compared with placebo-treated patients had reduced nasal mucosal eosinophil counts after 4 weeks of therapy (p <0.05). No serious or unusual drug-related adverse events were reported. Morning plasma cortisol concentrations after 4 weeks of therapy did not differ among groups. CONCLUSION: Fluticasone propionate aqueous nasal spray is more effective than terfenadine tablets for treatment of seasonal allergic rhinitis.

Administration, Intranasal↗
PubMed1996

One-year follow-up results of photorefractive keratectomy for low, moderate, and high primary astigmatism.

OBJECTIVE: To study the efficacy of excimer laser photorefractive keratectomy (PRK) for high, moderate, and low degrees of primary myopic astigmatism. PATIENTS AND METHODS: Ninety-two eyes of 54 patients with different degrees of compound myopic astigmatism underwent PRK. The eyes were divided by degree of refractive astigmatism into three groups-high (-2.75 to -5.0 diopters [D]), moderate (-1.25 to -2.50 D), and low (< or = 1.0 D). Refraction, corneal topography, slit-lamp findings, and visual acuity with and without correction were assessed. RESULTS: At 12 months, the mean reduction from the preoperative refractive cylinder was 80.7% in the high astigmatism group, 68.4% in the moderate astigmatism group, and 47.6% in the low astigmatism group. The post-treatment residual cylinder axis remained stable in 23 (38.3%) of 60 eyes and deviated in 37 (61.7%) of 60 eyes. The maximal deviation of the residual cylinder axis was 15 degrees. Of the 89.2% of eyes with low cylinder, 81.8% had moderate cylinder, and 85% of the eyes with high cylinder achieved a final uncorrected visual acuity between 20/20 and 20/35 at 12 months. CONCLUSIONS: A statistically significant reduction in the refractive cylinder was found in the high, moderate, and low astigmatism groups. The difference between the mean reduction of the high and moderate cylinders compared with the mean reduction of the low cylinders also was found to be statistically significant. The laser used in this study is an efficient tool for correcting high and moderate astigmatism. However, regarding low astigmatism, it was found to be less effective.

Adult↗
PubMed1996

Effect of capsulorhexis diameter on glare disability.

PURPOSE: To determine whether the diameter of the anterior capsulorhexis has an effect on postoperative glare. SETTING: Sapir Medical Center, Meir Hospital, Kfar Saba, Israel. METHODS: Forty patients had extracapsular cataract extraction (manual or phacoemulsification) through an intact continuous curvilinear capsulorhexis (CCC) of various sizes. The CCC diameter was measured and the opacity of the anterior and posterior capsules was evaluated before and after dilation of the pupils. Glare test (Miller-Nadler glare tester) was performed with the eyelid in a normal position and after lid elevation. RESULTS: The diameter of the CCC ranged from 3.50 to 7.00 mm (mean 4.87 mm). The anterior capsule was always opaque in the area of contact with the IOL material. None was graded clear; 60% were graded as +3. Mean glare disability prior to pupil dilation was 12.1 +/- 8.8 (SD) and after dilation, 17.3 +/- 9.7. There was no correlation between glare disability and the diameter of the capsulorhexis, the width of the exposed opacified capsular ring, or the grading of capsule opacification (anterior and posterior). Dilation of the pupil significantly increased glare disability (P = .016), unrelated to CCC diameter. CONCLUSION: A CCC larger than 3.5 mm does not induce significant glare.

Aged↗