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Biomedical subjects

M Lazar

Publications and source records attributed to M Lazar.

At least 19 recordsLinked to original sources
PubMed1992

[Acute systemic side-effects of topical timolol for glaucoma].

Topically-administered ophthalmic medication may reach clinically significant serum concentrations, as evidenced by the variety of systemic side effects reported. These drugs may interact with other drugs administered orally and intravenously, increasing the frequency and severity of their side-effects. We report 4 patients examined in the emergency room because of various systemic manifestations, in whom the symptoms could be attributed either to antiglaucomatous eye drops, or to interaction between these eye drops and systemic medication. Considering the high incidence of glaucoma (0.5-2%), physicians should be aware of the systemic side-effects of antiglaucomatous eye drops and of possible interaction between such treatment and systemic medications.

Aged↗
PubMed1992

Dosing problems in the use of topical ophthalmic drops.

The effect of two drops of the same drug, one instilled immediately after the other, was compared to the effect of a single drop in 100 healthy volunteers. The drugs investigated were tropicamide, 0.125%, and phenylephrine, 2.5%. The mydriatic effect of two drops was 30%-35% stronger than the effect achieved by a single drop.

Adult↗
PubMed1992

Activation of the gene encoding the glycolytic enzyme beta-enolase during early myogenesis precedes an increased expression during fetal muscle development.

We define the spatial and temporal patterns of expression of the gene encoding the glycolytic enzyme, beta-enolase, during mouse ontogenesis. Transcripts were detected by in situ hybridization using 35S labelled cRNA probes. The beta-enolase gene is expressed only in striated muscles. It is first detected in the embryo, in the cardiac tube and in newly formed myotomes. In the muscle masses of the limb, beta gene expression occurs at a low level in primary fibers, and subsequently greatly increases at a time which corresponds to the onset of innervation and secondary fiber formation. Later in development, it becomes undetectable in slow-twitch fibers. Our results demonstrate the multistep regulation of the beta-enolase gene. The regulation of this muscle-specific gene in somites is discussed in terms of the myogenic sequences of the MyoD family shown to be present when it is activated.

Animals↗
PubMed1992

Modulation of embryonic and muscle-specific enolase gene products in the developing mouse hindlimb.

During striated muscle development, the glycolytic enzyme enolase (EC 4.2.1.11) undergoes an isozymic transition, from the embryonic alpha alpha form towards the muscle-specific forms alpha beta and beta beta. The regulation of this transition was analyzed in mouse hindlimb muscles from embryonic day 15 (E15) to the adult stage. The quantitative modulations of the levels of the transcripts and subunits of alpha and beta enolase genes were determined. The absolute amounts of alpha and beta enolase mRNAs were estimated using in vitro synthesized transcripts as calibration standards, thus allowing an evaluation of their relative contribution at each stage examined. The muscle-specific beta enolase mRNA is already present at E15. Its level then increases and, from E17, this transcript becomes predominant. This accumulation is biphasic: a steep prenatal rise, corresponding to a net increase per fiber, accompanies the formation of secondary myofibers and the development of innervation; a second rise, beginning at postnatal day 5, is temporally correlated with the definitive specialization of the myofibers. Most of the decrease in alpha mRNA level occurs postnatally. No temporal or quantitative correlation between the up-regulation of beta mRNA and the down-regulation of alpha mRNA levels is observed throughout hindlimb muscle development. Quantitative immunoblotting analyses carried out in parallel show that the enolase isozymic transition is mainly controlled at the mRNA level.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Spontaneous resolution of proliferative vitreoretinopathy.

A case of proliferative vitreoretinopathy that spontaneously regressed, leading to reattachment of the retina, is presented. The importance of such a spontaneous resolution in terms of understanding the pathogenesis, and planning a treatment, is discussed.

Adult↗
PubMed1992

Recurrent choroidal detachment following timolol therapy in previously filtered eye. Choroidal detachment post filtering surgery.

A 64-year-old patient with open-angle glaucoma was treated with timolol following two unsuccessful filtering procedures. While on timolol therapy, she developed three episodes of choroidal detachment, hypotony and shallow anterior chamber. These findings resolved upon cessation of timolol and reappeared on 3 occasions shortly after reinstitution of the beta blocker therapy.

Choroid Diseases↗
PubMed1992

Tono-Pen tonometry in normal and in post-keratoplasty eyes.

Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 82 eyes of 82 patients with normal corneas and in 54 eyes of 54 patients who had undergone penetrating keratoplasty and whose corneas did not preclude the use of Goldmann tonometer. We found that the intraocular pressure (IOP) in 48% of the eyes with normal corneas and in 57% after keratoplasty has different measurements with Goldmann and Tono-Pen pressures of 3 mm Hg or more. Despite the correlation between the Goldmann tonometer and the Tono-Pen in the group of eyes with normal corneas (r = 0.83) as well as in the group of eyes after keratoplasty (r = 0.79) the Tono-Pen tended to significantly overestimate the Goldmann tonometer reading (p < 0.0001). The mean difference between the two instruments was highest across the lower IOP range (< 9 mm Hg) in the group of eyes after keratoplasty. Because the mean absolute values of the paired differences between Goldmann and Tono-Pen measurements varied significantly across all IOP intervals it was not possible to establish a correction factor which could be used when comparing the two measurements. Based on this study the Tono-Pen consistently overestimated the actual IOP in an unpredictable manner. Where possible Goldmann measurements of the IOP are still to be preferred.

Humans↗
PubMed1992

Trilateral retinoblastoma.

Retinoblastoma is the most common intraocular malignancy of childhood. Trilateral retinoblastoma is a syndrome characterized by bilateral ocular retinoblastoma in conjunction with an intracranial neuroblastic neoplasm in the pineal body, or in supraseller or parasellar location. We report the case of a three year old girl with trilateral retinoblastoma and review the literature on this subject.

Brain Neoplasms↗
PubMed1991

The Viviparous-1 developmental gene of maize encodes a novel transcriptional activator.

The Viviparous-1 (Vp1) gene of maize is specifically required for expression of the maturation program in seed development. We show that Vp1 encodes a 73,335 dalton protein with no detectable homology to known proteins. An acidic transcriptional activation sequence was identified by fusion to the GAL4 DNA-binding domain. Expression of VP1 in maize protoplasts resulted in strong activation (greater than 130-fold) of a reporter gene fused to the promoter of a presumptive target gene. The acidic domain in VP1 was essential for transactivation and could be functionally replaced by the activator sequence of the herpes simplex virus VP16 protein. Our results indicate that VP1 is a novel transcription factor possibly involved in potentiation of a seed-specific hormone response.

Amino Acid Sequence↗
PubMed1991

[Procurement of corneas for transplantation].

We prospectively studied all deaths in this hospital from July 1, 1989 through December 31, 1989 for possible eye donations. During this period 539 patients died, of whom, 219 were suitable candidates for donation, and 61 donations were obtained (11.3%). In the course of the study the procurement rate increased progressively as a result of a higher level of effort and awareness by the medical staff.

Cornea↗
PubMed1991

Atropine in keratoplasty for keratoconus.

A prospective study of 83 eyes in 76 consecutive patients undergoing keratoplasty for keratoconus is presented in which 1% atropine was routinely given at the end of surgery. No case of permanent mydriasis was seen. The syndrome described in the literature of fixed, dilated pupil after the use of atropine in keratoplasty no longer seems to exist and the warning against strong mydriatics appears unwarranted.

Adolescent↗
PubMed1991

Intentional retention of Descemet's membrane during keratoplasty.

Detachment of the host's Descemet membrane inadvertently occurred while removing the decompensated graft in a patient undergoing rekeratoplasty. The membrane was purposefully left intact and the new graft sutured on top of it. In this way, opening of the anterior chamber was avoided and the operation completed as an 'extraocular' procedure. The graft and the membrane have remained clear during 3 years of follow-up.

Adult↗
PubMed1991

Prevention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topical clonidine.

We studied the ability of topical clonidine, an alpha-agonist, to suppress the acute rise in intraocular pressure (IOP) following neodymium-YAG posterior capsulotomy (YPC). In a randomized controlled trial 63 eyes were pretreated with one drop of either 0.25% clonidine or saline 1 h before performing YPC and immediately following the procedure. The greatest IOP rise in the saline treated eyes occurred in the second hour after YPC, when the mean (+/- SD) IOP rose from a baseline pressure of 12.7 +/- 3.2 to 18.7 +/- 10.7 mmHg. In clonidine treated eyes, the IOP fell from a mean of 11.9 +/- 3.4 to 9 +/- 3.3 mmHg 2 h postoperatively. In the saline treated group 9 eyes (27%) developed an IOP rise greater than 10 mmHg. Clonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗