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Biomedical subjects

M Pop

Publications and source records attributed to M Pop.

At least 19 recordsLinked to original sources
PubMed2006

hHR23B is required for genotoxic-specific activation of p53 and apoptosis.

Rad23 proteins function in both DNA repair and protein stability regulation. As ubiquitinated forms of p53 are stabilized after DNA damage in concert with p53 functional activation, and human Rad23 proteins (hHR23A and B) regulate p53 stability in unstressed cells, the role of hHR23B in post-genotoxin regulation of p53 was investigated. Depletion of hHR23B by specific short interfering RNA before genotoxic exposure attenuated p53, p21 and bax induction, abrogated the accumulation of ubiquitinated p53 and suppressed apoptosis. Expression of ubiquitin derivatives with all lysines mutated except K48 or K63 demonstrated that K48-linked p53-ubiquitin conjugates were specifically induced after DNA damage. hHR23B, along with native and ubiquitinated p53, accumulated in chromatin after genotoxic exposure, and the accumulation of ubiquitinated p53 in chromatin was prevented by hHR23B depletion. Chromatin immunoprecipitation analysis demonstrated that hHR23B and p53 both localized to the p21 promoter shortly after DNA damage. hHR23B thus plays a critical role in the activation and function of p53 after specific genotoxic exposures.

Apoptosis↗
PubMed2002

Complete genome sequence and comparative analysis of the metabolically versatile Pseudomonas putida KT2440.

Pseudomonas putida is a metabolically versatile saprophytic soil bacterium that has been certified as a biosafety host for the cloning of foreign genes. The bacterium also has considerable potential for biotechnological applications. Sequence analysis of the 6.18 Mb genome of strain KT2440 reveals diverse transport and metabolic systems. Although there is a high level of genome conservation with the pathogenic Pseudomonad Pseudomonas aeruginosa (85% of the predicted coding regions are shared), key virulence factors including exotoxin A and type III secretion systems are absent. Analysis of the genome gives insight into the non-pathogenic nature of P. putida and points to potential new applications in agriculture, biocatalysis, bioremediation and bioplastic production.

Bacterial Proteins↗
PubMed2001

Clear lens extraction with intraocular lens followed by photorefractive keratectomy or laser in situ keratomileusis.

OBJECTIVE: To study photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) after clear lens extraction (CLE) with intraocular lens (IOL) implantation for hyperopia or astigmatism. DESIGN: Retrospective, noncomparative interventional case series. PARTICIPANTS: Sixty-five eyes (55 subjects) had CLE with posterior chamber IOL implants for hyperopia up to 12.25 diopters (D); 31 eyes were retreated with PRK, and 34 eyes were retreated with LASIK for residual ametropias. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, Nidek Co., Tokyo, Japan. MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, and halos were evaluated before surgery and at 1, 3, 6, and 12 months postoperative. RESULTS: Forty-seven eyes were evaluated at the 12-month postoperative examination: 96% of these eyes had spherical equivalents (SE) within +/-2 D of emmetropia, 79% of eyes had SE within +/-1 D of emmetropia and 51% of eyes had SE within +/-0.50 D of emmetropia. Eighty-five percent of the eyes at 12 months postoperative had uncorrected visual acuity of 20/40 or better, and 46% of eyes had uncorrected visual acuity of 20/20 or better. Eighty-seven percent of the eyes at 12 months postoperative had uncorrected visual acuity within 1 Snellen line of their initial best spectacle-corrected visual acuity (BSCVA) before all treatment. No eye lost 2 Snellen lines of BSCVA at 3, 6, or 12 months after PRK or after LASIK. CONCLUSIONS: IOL implantation for CLE, although an invasive technique, resulted in better refractive outcomes without laser-related clinical complications after PRK or LASIK adjustment.

Adult↗
PubMed2001

Predicting sulcus size using ocular measurements.

PURPOSE: To predict sulcus size using ocular measurements. SETTING: Michel Pop Clinics, Montreal, Quebec, Canada. METHODS: Forty-three eyes were evaluated using several techniques. Ultrasound biomicroscopy (UBM) echograms were taken to measure the anterior chamber depth (ACD), sulcus size, and central corneal thickness. The limbus size was measured with a caliper. Axial length, ACD, and pachymetry were measured by contact ultrasonography. Refraction and corneal power were also evaluated. RESULTS: The coefficient of linear regression was 0.05 between the limbus and the sulcus size (P =.78), 0.76 between ultrasonography and UBM ACD measurements (P <.001), and 0.69 between ultrasonography and UBM pachymetry (P <.001). Paired t tests showed that ultrasound and UBM ACD measurements were not statistically different (P =.70) but that ultrasound and UBM pachymetry measurements were (P <.001). The sulcus versus limbus difference was 0.6 mm for myopia and 0.3 mm for hyperopia. A backward elimination multiple regression performed with all measures to predict sulcus size resulted in the following formula: Sulcus size = 18.9 - 0.023 x sphere + 0.15 x mean keratometry (R = 0.49; P =.005; statistical power = 0.89; standard error of estimate = 0.5 mm). CONCLUSION: Traditional estimation of sulcus size through limbal measurement is inadequate because limbus size alone cannot predict sulcus size. A general formula using the sphere and the mean corneal power can help predict sulcus size. Corneal power was significantly and negatively correlated with sulcus and limbus size as well as sphere. The standard error of sulcus measurement by UBM was 0.4 mm.

Adult↗
PubMed2001

[Ocular cysticercosis - case report].

This paper presents a particularly case regarding ophthalmic cysticercosis. It was necessary the association of clinical dates with the paraclinical investigations (echography, immunological tests) to degree the diagnosis.

Adult↗
PubMed2001

[Ocular myopathies - cause of exophthalmia].

It presents the "thickenings" of the extraocular muscles that can cause exophthalmos. It makes the difference between myositis limited to the orbit and the systemic myopathies and endocrine myopathies.

Adolescent↗
PubMed2000

Verotoxin targets lymphoma infiltrates of patients with post-transplant lymphoproliferative disease.

Post-transplant lymphoproliferative disease (PTLD) is an invasive, EBV expressing B lymphoma and a major cause of morbidity and mortality following organ transplantation. Presently there is limited therapy available; rather the patient often loses the allograft or succumbs to the malignancy. CD77 (or globotriaosyl ceramide -Gb(3)) is a germinal center B cell marker [Gregory et al. Int J Cancer 1998;42:213-20; Gregory et al., J Immunol 1987;139:313-8; Mangeney et al. Eur J Immunol 1991;21:1131-40], expressed on most EBV infected B cells and is the receptor for the E. coli derived verotoxin (VT) [Lingwood CA. Advances in Lipid Research 1993;25:189-212]. We present the basis of a possible novel approach to PTLD therapy utilizing the specific targeting of VT to the infiltrating lymphoma cells. Biopsies of adenoid, kidney or liver tissue of four PTLD patients were stained with verotoxin to determine expression of CD77. VT is a potent inducer of necrosis/apoptosis of receptor positive cells. In each PTLD case, the infiltrating EBV positive B lymphoma cells were strongly and selectively stained with VT, identifying CD77 as a new marker for these cells. For such individuals, VT might provide the basis of an approach to control their malignancy.

Adolescent↗
PubMed2000

Functional outcome and satisfaction after photorefractive keratectomy. Part 2: survey of 690 patients.

PURPOSE: To document patient satisfaction and self-perceived quality of vision after bilateral photorefractive keratectomy (PRK). DESIGN: Noncomparative, interventional case series. PARTICIPANTS: Consecutive patients who underwent bilateral PRK from May 1994 through May 1997 by the 12 surgeons of four collaborating centers with a minimum of 4 months since the last surgery and up to 30 months since the first surgery. METHODS: A questionnaire with known psychometric properties was self-administered by the patients. MAIN OUTCOME MEASURES: Responses to individual questions and scale scores. RESULTS: A total of 929 questionnaires were sent, of which 690 were answered and returned (74.3% response rate). The preoperative spherical equivalent ranged from -0.38 diopters [D] to -27.75 D (mean, -5.32 D; standard deviation, 2.85 D). Although 91.8% of the patients were satisfied or very satisfied with their surgery, 96.3% considered that their main goal had been reached, and 95.7% would still choose to have surgery if they had it to do over. The degree of satisfaction was proportional to the postoperative uncorrected visual acuity in the best eye expressed in LogMAR (r = -0.18, P: = 0. 0001) and was negatively correlated with the importance of the corneal haze (r = -0.23, P = 0.0001). Daytime glare was reported to be greater than before surgery by 55.1% of patients. A decrease in night vision was reported by 31.7% of patients, and 31.1% of patients reported increased difficulty driving at night because of their vision. CONCLUSIONS: Overall satisfaction after PRK for low to severe myopia appears to be very good. Glare and night vision disturbance, particularly bothersome for night driving, seem to constitute significant secondary effects that deserve further investigation and should be kept in mind for future improvements in the technique.

Adolescent↗
PubMed2000

Photorefractive keratectomy versus laser in situ keratomileusis: a control-matched study.

OBJECTIVE: Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) outcomes were compared at 1, 3, 6, and 12 months after surgery. DESIGN: Retrospective, nonrandomized, comparative study. PARTICIPANTS: One hundred seven LASIK-treated eyes (58 patients) and 107 PRK-treated eyes (91 patients) having myopia between -1 and -9.50 diopters (D). All LASIK-treated eyes were analyzed retrospectively and matched with PRK-treated eyes having sphere within +/-0.25 D, +/-1 D of cylinder, and +/-7 years of age. INTERVENTION: For PRK and LASIK, the refractive surgery was performed with the slit-scanning excimer laser Nidek EC-5000, (Nidek Co. Tokyo, Japan) MAIN OUTCOME MEASURES: Manifest refraction, best-spectacle and uncorrected Snellen visual acuity, haze, halos, and keratometry were evaluated before surgery and up to 12 months after surgery. RESULTS: Seventy percent of eyes were evaluated at the 12-month postoperative exam. Of these eyes, 83% of LASIK cases and 86% of PRK cases had uncorrected visual acuities of 20/20 or better. Refractions within +/-0.5 D represented 78% of the LASIK eyes and 83% of the PRK eyes at that follow-up. Patients who underwent LASIK reported halos twice as often as patients who underwent PRK using a subjective scale. The odds ratio of high halos for LASIK versus PRK was 3.50 (95% confidence interval, 1.89-6.46; P<0.0001). At 1 month after surgery, 64% of the LASIK eyes were within +/-0.50 D compared with 77% of the PRK eyes. No eye lost 2 Snellen lines of best corrected visual acuity at 6 or 12 months after surgery. Ten PRK eyes (9.3%) and three LASIK eyes (2.8%) were retreated. CONCLUSIONS: PRK and LASIK achieved equal refractive outcomes at all postoperative follow-ups, but LASIK patients were twice as likely to experience halos.

Adult↗
PubMed2000

Results of bilateral photorefractive keratectomy.

OBJECTIVE: To study the refraction and potential risks of bilateral photorefractive keratectomy for myopia. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Four hundred eighteen consecutive patients (836 eyes) with myopia from -18 to -0.50 diopters (D) had bilateral simultaneous refractive surgery. INTERVENTION: Refractive surgery was performed with the Nidek EC-5000 slit-scanning excimer laser (Nidek Co., Tokyo, Japan). MAIN OUTCOME MEASURES: Manifest refraction, Snellen best spectacle-corrected visual acuity (BSCVA) and uncorrected visual acuity, haze, and halos were evaluated for 12 months after surgery. Both eyes of each patient were examined at the same follow-up after initial treatment. RESULTS: At 12 months after surgery, 95% of eyes were within +/- 1D of emmetropia, and 0.4% of patients had residual anisometropia more than 2 D. Thirty-three eyes (3.9%) were retreated, whereas 5 patients (1.2%) had retreatments in both eyes. Odds ratios between unilateral versus bilateral postoperative events were evaluated for the retreatments (1:0.22; P = 0.001), undercorrections more than 1 D (1:0.17; P < 0.0001), overcorrections more than 1 D (1:0.23; P < 0.0001), loss of 1 line of BSCVA (1:0.44; P < or = 0.002), and loss of 2 lines of BSCVA (1:0.18; P = 0.013). At 12 months after surgery, one eye with a loss of 2 lines of BSCVA was treated for haze more than 1; the fellow eye had haze 0.75. No patient had bilateral haze more than 1. At 12 months after surgery, no patient lost 2 lines of BSCVA in both eyes. There was a higher incidence of halos in both eyes rather than in one eye only (odds ratio: 4.17; P < 0.0001). No postoperative infections occurred. CONCLUSIONS: Bilateral events occurred approximately 2.5 to 4 times less often than unilateral events, except for the incidence of halos. The calculated odds ratio did not show an increased risk for the fellow eye while performing bilateral surgery, although not exempted from the risk of infection. It may be difficult to predict a complication in the fellow eye based on the results of the first operated eye.

Adult↗
PubMed1998

Laser thermal keratoplasty for the treatment of photorefractive keratectomy overcorrections: a 1-year follow-up.

OBJECTIVE: To evaluate the results of holmium:YAG laser thermal keratoplasty (LTK) treatment for overcorrection of myopia after a photorefractive keratectomy (PRK) treatment. PARTICIPANTS: Thirty-six eyes (33 patients) were treated with a nontouch holmium:YAG laser (Sunrise Technologies, Model LTK, Freemont, CA) because of hyperopia (mean +/- standard deviation of +2.06 diopter [D] +/- 0.75, ranging from +1.0 to +3.5 D) following a PRK treatment. A control LTK group treated for primary hyperopia, who had preoperative refraction values not statistically different from the PRK + LTK group, was used for comparison. INTERVENTION: The number of spots applied varied from 8 to 24, and the energy used was 200 to 240 mJ. A maximum of three rings of four to eight spots were placed between 6 and 8 mm from the visual axis. RESULTS: Twelve months after the LTK retreatment for PRK patients, mean refraction was +1.14 D +/- 1.09. Regression from 1 to 12 months was 0.5 D +/- 1.1. At 12 months, 50% of eyes were within 1 D of emmetropia; 93% of eyes had uncorrected visual acuity (UCVA) of 20/40 or better; and 24% of eyes had UCVA of 20/20 or better. Refraction was not stable for 11 eyes (34%) that regained original sphere values or higher. Best-corrected visual acuity was not affected, and haze was not increased nor decreased by the procedure. CONCLUSIONS: Twelve months after an LTK retreatment for an initial PRK, two thirds of the retreated eyes did not need further retreatments. However, clinical data showed that LTK should be kept for +1 to +2 D of hyperopia for PRK overcorrection retreatments.

Adult↗
PubMed1998

Prompt re-treatment after photorefractive keratectomy.

PURPOSE: To study eyes that received a photorefractive keratectomy (PRK) retreatment 1 to 4 months after the first treatment and describe refractive stability and complications. SETTING: Michael Pop CLinics, Montreal, Canada. METHODS: Twenty-six eyes of 20 patients were re-treated for undercorrection and, regression with or without haze. Postoperative refractions were performed at 1, 2, 3, and 6 months. Haze was evaluated on a scale of 0 to 4. RESULTS: Ninety percent of the 21 eyes followed for 6 months after re-treatment achieved an uncorrected visual acuity of 20/40. At 6 months, 67 and 95% of eyes were within +/- 0.50 diopter (D) and +/- 1.00 D, respectively. Regression between 1 and 6 months after re-treatment was 0.71 D, which represented less than one half that observed after the initial treatment. Six months after re-treatment, haze decreased by half, and no eye had haze above 1. Best corrected visual acuity (BCVA) before treatment was well correlated with values 6 months after re-treatment (P < .001). At 6 months, 1 eye lost two lines of BCVA but had an acuity of 20/30 and 2 eyes lost one line of BCVA. CONCLUSION: Prompt re-treatment after PRK for myopia allowed management of undercorrections and regressions with low morbidity and high refractive stability. By re-treating promptly, no additional complications were created and patients avoided long periods of unsatisfactory vision.

Adolescent↗
PubMed1996

Photorefractive keratectomy retreatments for regression. One-year follow-up.

PURPOSE: Ninety eyes were retreated to correct myopic regression, with or without corneal haze, after primary photorefractive keratectomy (PRK); astigmatism ranging from -0.50 to -3 diopters (D) was present in 43 eyes. RESULTS: The sphere (mean +/- standard deviation) was -2.82 +/- 1.74 D before repeat surgery. At 6 months, the mean was +0.30 D; at 1 year, it was -0.17 D. Patients were divided into two groups: group 1 included 56 eyes with little or no haze (< or = 1). The mean sphere value for this group was -2.13 D before retreatment; at 1 year, it was -0.20 +/- 0.76 D. At 6 months, 84% of sphere values were within +/- 1 D of the intended correction, with a mean haze value of less than 0.5, similar to that before repeat surgery; there was a mean gain of 0.25 Snellen line of best-corrected visual acuity. Astigmatism equal or greater than -0.5 D was present in 34 eyes (mean, -1.17 +/- 0.55 D). At 6 months, astigmatism was reduced to -0.45 +/- 0.48 D. The second group included 34 eyes with corneal haze greater than 1 (mean, 2.7). The mean sphere value was -3.95 D before photorefractive keratectomy and -0.12 +/- 1.48 D 1 year after treatment. Fifty percent of the mean sphere values were within +/- 1 D at 6 months, with a mean haze value of 1. The gain in mean best-corrected visual acuity was 1.3 Snellen lines. The mean astigmatism in nine eyes was -1.75 +/- 0.75 D before photorefractive keratectomy and -0.72 +/- 0.78 D 6 months after treatment. CONCLUSION: There is a significant difference in the outcome predictability between the two groups. A second photorefractive keratectomy can be done 6 months after the primary treatment in patients with regression with or without trace haze. This group has a High predictability in achieving a good correction, with a low complication rate. When haze is present, retreatments are less predictable with 40% of patients overcorrected. Generally, however, these eyes have a statistically significant decrease in haze (Student's t test; P < 0.01) and an improvement in best-corrected visual acuity.

Cornea↗
PubMed1995

Multizone/multipass photorefractive keratectomy: six month results.

A multizone/multipass photorefractive keratectomy (MP-PRK) technique was used to treat 315 eyes with the 193 nm VISX 20/20 excimer laser. Algorithms were developed to treat the full range of myopia, including 170 low myopic eyes (-1.0 to -6.0 diopters [D]), 105 moderately myopic eyes (-6.0 to -10.0 D), and 40 highly myopic eyes (-10.0 to -27.0 D). Preoperative mean myopia was -6.69 D; astigmatism equal to or greater than -0.5 D (mean -1.18 D) was present in 193 eyes. At one month postoperatively, most eyes were slightly hyperopic (mean +0.8 D); this regressed to a mean of -0.16 D. At six months, 95.5% of low myopes, 84.8% of moderate myopes, and 59.5% of high myopes were within 1.0 D of emmetropia; 78.4% of high myopes were within 2.0 D of the intended correction. There was no loss of 20/40 best corrected visual acuity (BCVA) at six months; a significant gain in 20/25 BCVA was seen in the moderate and high myopia groups (P < .05). At six months, uncorrected visual acuity was 20/25 in 89.4% of low myopes, 75.0% of moderate myopes, and 25.7% of high myopes. Mean haze value was 0.48 at one month and was not significantly different among the three groups (0.44, 0.52, 0.51, respectively). A control group treated with the one-pass multizone technique had a significantly higher amount of haze: 1.05 (P < .01). The data presented compare favorably with those obtained from other centers. Based on these results, we believe that MP-PRK is a safe, reliable technique to correct most low, moderate, and high myopia.

Adult↗
PubMed1994

Oral health status among schoolchildren in Romania, 1992.

In Romania, systematic information on the occurrence of oral diseases in children is scarce. The purpose of the present study was to describe the prevalence and the pattern of dental caries in schoolchildren, and to use the data to provide a baseline for planning and evaluation of oral health care. A national sample of children at grade 1 (n = 729) and grade 6 (n = 660) was chosen consistent with the WHO pathfinder principle. Clinical examinations were carried out according to the recording system for the Danish Municipal Dental Service and the following results were obtained. In children of grade 1 (7-yr-olds) the prevalence proportion of caries in primary teeth was 86% and in permanent teeth 39%. The mean caries indices were 11.4 defs and 1.3 DMFS. At grade 6 (12-yr-olds) the prevalence proportion of caries in primary teeth was 17% and in permanent teeth 90%. The mean caries experience was 0.8 defs and 6.5 DMFS, and a mean of 4.1 DMFT was observed. In both groups, the D-component of the caries index was dominant. The children were also classified by caries severity zone. At grade 1, 61% had a very severe pattern of caries in the primary teeth, i.e. caries in pits/fissures, proximal surfaces, smooth surfaces, and incisors. Forty-three percent of the children at grade 6 showed this pattern in permanent teeth. In Romanian schoolchildren the present level and pattern of dental caries are most severe and the implementation of oral health promotion and prevention at the community level is urgently needed.

Adolescent↗