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Biomedical subjects

M Lazar

Publications and source records attributed to M Lazar.

At least 73 records · Page 4Linked to original sources
PubMed1995

Influence of the time interval between instillation of two drops of cyclopentolate 1% on refraction and dilation of the pupil in children.

PURPOSE: Because the usual length of time to instill two drops of cyclopentolate 1% (five to ten minutes) is time-consuming and inconvenient to clinical staff as well as to the child and the child's parents, we investigated the influence of the time interval between the instillation of the two drops on refraction and mydriasis in children. METHODS: We conducted a crossover study on 48 children at the Tel-Aviv Medical Center. Gender, iris color, ethnic origin, and age were recorded. Two cyclopentolate 1% eyedrops were instilled at a one- or five-minute time interval. Retinoscopy was performed and the mydriatic effect was recorded. One week later, the procedure was repeated, this time with a different time interval. RESULTS: The time interval between the instillation of the two drops had no significant influence on retinoscopy results (P = .65 and P = .50 for right and left eyes, respectively) or on pupil dilation (P = .377 and P = .113 for right and left eyes, respectively). CONCLUSIONS: Instilling two drops of cyclopentolate 1% one minute apart is as effective as instilling them five minutes apart.

Child↗
PubMed1995

Differential expression of alpha- and beta-enolase genes during rat heart development and hypertrophy.

We have analyzed the transition between isoforms of the glycolytic enzyme enolase (2-phospho-D-glycerate hydrolyase; EC 4.2.1.11) in rat heart during normal and pathological growth. A striking fall in embryonic alpha-enolase gene expression occurs during cardiac development, mostly controlled at pretranslational steps. In fetal and neonatal hearts, muscle-specific beta-enolase gene expression is a minor contributor to total enolase. Control mechanisms of beta-enolase gene expression must include posttranscriptional steps. Aortic stenosis induces a rapid and drastic decrease in beta-enolase transcript level in cardiomyocytes, followed by the fall in beta-subunit level. In contrast, alpha-enolase transcript level is not significantly altered, although the corresponding subunit level increases in nonmuscle cells. We conclude that, like fetal heart, hypertrophic heart is characterized by a high ratio of alpha- to beta-enolase subunit concentrations. This study indicates that the decrease in beta-enolase gene expression may be linked to beneficial energetic changes in contractile properties occurring during cardiac hypertrophy.

Aging↗
PubMed1995

Congenital fibrosis of the extraocular muscles (autosomal dominant congenital external ophthalmoplegia): genetic homogeneity, linkage refinement, and physical mapping on chromosome 12.

Congenital fibrosis of the extraocular muscles (CFEOM) is an autosomal dominant syndrome of congenital external ophthalmoplegia and bilateral ptosis. We previously reported linkage of this disorder in two unrelated families to an 8-cM region near the centromere of human chromosome 12. We now present refinement of linkage in the original two families, linkage analysis of five additional families, and a physical map of the critical region for the CFEOM gene. In each of the seven families the disease gene is linked to the pericentromeric region of chromosome 12. D12S345, D12S59, D12S331, and D12S1048 do not recombine with the disease gene and have combined lod scores of 35.7, 35.6, 16.0, and 31.4, respectively. AFM136xf6 and AFMb320wd9 flank the CFEOM locus, defining a critical region of 3 cM spanning the centromere of chromosome 12. These data support the concept that this may be a genetically homogeneous disorder. We also describe the generation of a YAC contig encompassing the critical region of the CFEOM locus. This interval has been assigned cytogenetically to 12p11.2-q12 and spans the centromere of chromosome 12. These results provide the basis for further molecular analyses of the structure and organization of the CFEOM locus and will help in the identification of candidate genes.

Chromosome Mapping↗
PubMed1995

Ocular pigmentation protects the rabbit retina from gentamicin-induced toxicity.

PURPOSE: This study was designed to investigate the possibility that gentamicin-induced retinal toxicity is dependent on ocular pigmentation by comparing the effects of the drug on the functional and morphologic integrity of the retina in albino and pigmented rabbits. METHODS: In each rabbit, a solution of gentamicin sulfate was injected into the vitreous of one eye, and saline was injected into the other eye. Retinal function was assessed by electroretinogram (ERG) at different time intervals after injection. Retinal structure was examined at the light microscopic level. RESULTS: In albino and pigmented rabbits, functional retinal damage developed to a maximal level within the first week after gentamicin injection. Thereafter, gradual recovery could be seen in eyes that suffered less than 80% maximal reduction in the ERG b-wave. For each dose >0.1 mg studied, retinal damage was more severe in the albino rabbits than in the pigmented ones. The degree of damage was not affected by the level of ambient illumination, nor was it reduced by the administration of N-acetylcystein, a free radical scavenger, together with gentamicin. CONCLUSIONS: Ocular pigmentation partially protects the rabbit retina from the toxic action of gentamicin. This protection probably reflects binding of the drug by the melanin, which thereby reduces the concentration of the free gentamicin. When the initial gentamicin-induced retinal damage is expressed in < 80% reduction in the ERG, substantial recovery may occur in both strains of rabbits.

Albinism↗
PubMed1995

CT appearance of a traumatic cataract.

We describe a case of a traumatic cataract that presented on CT as a hypodense lens with a hyderdense rim. The finding reflects the pathogenesis of this entity: a capsular tear and consequent entry of fluid into the lens.

Cataract↗
PubMed1995

Panuveal malignant mesenchymoma.

Intraocular malignant mesenchymal tumors are very rare, and only a few case reports of such primary and metastatic tumors have been reported. We report a case of a malignant mesenchymoma involving the entire uveal tract. A 21-year-old woman presented with a tumor on the whole iris of the right eye, which caused intractable glaucoma. Upon enucleation of the eye, a very anaplastic tumor was found to occupy the whole uveal tract; its features were compatible with a tumor of mesenchymal origin, including rhabdomyosarcomatous and liposarcomatous characteristics. Choroidal osteoma was a coincidental finding. The histologic findings of the tumor were of two types of malignant mesenchymal tumors, and therefore the diagnosis of malignant mesenchymoma was made. This is to our knowledge the first tumor of its kind to be reported intraocularly.

Adult↗
PubMed1994

Combined timolol and pilocarpine vs pilocarpine alone and timolol alone in the treatment of glaucoma.

We compared the effects of pilocarpine 4% alone, timolol 0.5% alone, and a combination of timolol 0.5% and pilocarpine 4% in the treatment of glaucoma. We treated 43 patients with glaucoma using each drug and then with the combination of drugs for four weeks each. Only patients with a morning intraocular pressure of at least 24 mm Hg without treatment were included. The patients were examined, after one and four weeks of treatment with pilocarpine, timolol, or combined timolol 0.5% and pilocarpine 4%, before the morning dose and at two and five hours after it. At the end of the study, the mean reduction in intraocular pressure from baseline was 9.2 +/- 5.1 mm Hg (28.5% +/- 12.7%) with combined timolol 0.5% and pilocarpine 4%, 5.6 +/- 3.6 mm Hg (17.6% +/- 9.7%) with pilocarpine, and 7.5 +/- 5.0 mm Hg (21.2% +/- 12.6%) with timolol. Intraocular pressure was consistently lower with the combination treatment than with timolol or pilocarpine alone. We believe that this combined solution of timolol-pilocarpine is a valuable contribution to the treatment of open-angle glaucoma.

Administration, Topical↗
PubMed1994

Application of eye drops to the medial canthus.

BACKGROUND: Our purpose was to investigate the efficacy of instillation of eye drops in the medial canthus with the lids closed at the time of application. METHODS: The pupils of 50 healthy volunteers were dilated with tropicamide 0.125%. The effect of the drug on pupillary dilatation when instilled in one eye with the lids closed was compared to its effect when instilled in the conventional mode in the other eye. RESULTS: Maximal mydriasis achieved was 2.75 +/- 0.76 mm in the eye with closed lids and 2.8 +/- 0.77 mm in the eye in which eye drops were instilled in the conventional mode. CONCLUSION: Eye drop instillation in the medial canthus with the lids closed at the time of application seems to be an effective means of ophthalmic drug delivery.

Adult↗
PubMed1994

Opening by the Nd:YAG laser of the anterior portion of the capsular bag in the treatment of delayed onset pseudophakic endophthalmitis.

We report on a pseudophakic patient with delayed onset endophthalmitis. The patient was treated twice topically and systemically with antibiotic and steroids with temporary response to treatment. The inflammation recurred twice upon withdrawal of treatment. Upon the third relapse of endophthalmitis the anterior portion of the capsular bag was opened by Nd:YAG laser. A third course of systemic and topical antibiotic and steroid treatment was followed by permanent resolution of inflammation. No relapse occurred during 18 months of follow-up.

Aged↗
PubMed1993

Catecholaminergic neurons result from intracerebral implantation of embryonal carcinoma cells.

A replication-defective retrovirus was used to introduce the marker gene nlsLacZ into the murine embryonal carcinoma (EC) cell line PCC7-S-aza-R-1009. Undifferentiated EC cells were implanted into the central nervous system of adult rats. One month later, the grafted cells continued to express the nlsLacZ gene. Immunohistochemical analysis demonstrated the presence of EC-derived neurons. These neurons were capable of expressing tyrosine hydroxylase and extended neurites into the host parenchyma. EC-derived glial cells could not be detected. There was no evidence of tumorigenicity. These results demonstrate the utility of EC cells for introduction of exogenous gene products into the central nervous system in experimental models of gene therapy.

Animals↗