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At least 505 records · Page 28Linked to original sources
PubMed1999

Use of microdissection and molecular genetics in the pathologic diagnosis of retinoblastoma.

BACKGROUND/PURPOSE: Retinoblastoma results from mutations or loss of both alleles of the retinoblastoma gene. Although retinoblastoma is usually recognized clinically, some forms of the disease can elude diagnosis. The purpose of this study was to determine whether the use of molecular genetics to detect a loss of heterozygosity (LOH) in the retinoblastoma gene could assist the ocular pathologist in the diagnosis of this malignancy. METHODS: Deoxyribonucleic acid (DNA) was obtained from tumor cells microdissected from three ocular specimens from two patients with diffuse retinoblastoma. Polymerase chain reaction was used to detect two microsatellite markers (D13S153 and D13S118) of the retinoblastoma gene. Loss of heterozygosity was identified when one of the two polymorphic alleles was present in the DNA from normal tissue but absent or reduced in the DNA obtained from tumor cells. RESULTS: Loss of heterozygosity was identified in all three specimens from the two patients with diffuse retinoblastoma. In one patient, the diagnosis of retinoblastoma was based on identification of LOH from tumor cells obtained from vitrectomy. CONCLUSIONS: This study demonstrates that identification of LOH in retinoblastoma cells not only can contribute to our understanding of the molecular genetics of this tumor, but also can help the ocular pathologist in the diagnosis of atypical forms of the disease.

Adolescent↗
PubMed2001

The measurement of three dimensional dose distribution of a ruthenium-106 ophthalmological applicator using magnetic resonance imaging of BANG polymer gels.

The BANG (MGS Research Inc., Guilford, CT) polymer gel has been used as a dosimeter to determine the three-dimensional (3D) dose distribution of a ruthenium-106 (Ru-106) ophthalmologic applicator. An eye phantom made of the BANG gel was irradiated with the Ru-106 source for up to 1 h. The phantom and a set of calibration vials were scanned simultaneously in a GE 1.5 T MR imager using the Hahn spin-echo pulse sequence with a TR of 2000 ms and two TEs of 20 ms and 100 ms. The T(2) values were evaluated on a pixel-by-pixel basis using custom-built software on a DEC alpha workstation and converted to dose using calibration data. Depth doses and isodose lines of the Ru-106 eye-plaque were generated. It is concluded that the BANG gel dosimetry offers the potential for measuring the 3D dose distributions of an ophthalmologic applicator, with high spatial resolution and relatively good accuracy.

Brachytherapy↗
PubMed2004

Identification of three novel RB1 mutations in Brazilian patients with retinoblastoma by "exon by exon" PCR mediated SSCP analysis.

AIMS: To carry out a retrospective study, screening for mutations of the entire coding region of RB1 and adjacent intronic regions in patients with retinoblastoma. METHODS: Mutation screening in DNA extracts of formalin fixed, paraffin wax embedded tissues of 28 patients using combined "exon by exon" polymerase chain reaction mediated single strand conformational polymorphism analysis, followed by DNA sequencing. RESULTS: Eleven mutations were found in 10 patients. Ten mutations consisted of single base substitutions; 10 were localised in exonic regions (eight nonsense, one missense, and one frameshift) and another one in the intron-exon splicing region. Three novel mutations were identified: a 2 bp insertion in exon 2 (g.5506-5507insAG, R73fsX77), a G to A transition affecting the last invariant nucleotide of intron 13 (g.76429G>A), and a T to C transition in exon 20 (g.156795T>C, L688P). In addition, eight C to T transitions, resulting in stop codons, were found in five different CGA codons (g.64348C>T, g.76430C>T, g.78238C>T, g.78250C>T, and g.150037C>T). Although specific mutation hotspots have not been identified in the literature, eight of the 11 mutations occurred in CGA codons and seven fell within the E1A binding domains (codons 393-572 and 646-772), whereas five were of both types-in CGA codons within E1A binding domains. CONCLUSIONS: CGA codons and E1A binding domains are apparently more frequent mutational targets and should be initially screened in patients with retinoblastoma. Paraffin wax embedded samples proved to be valuable sources of DNA for retrospective studies, providing useful information for genetic counselling.

Brazil↗
PubMed1998

Involvement of interleukin-1beta-converting enzyme in apoptosis of irradiated retinoblastomas.

PURPOSE: To investigate whether interleukin-1beta-converting enzyme (ICE), a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, is involved in gamma-irradiation-induced apoptosis (programmed cell death) of human retinoblastoma cells. METHODS: The induction of apoptotic cell death in human retinoblastoma cell lines WERI-Rb-1 and Y79 by gamma-irradiation was determined with a modified 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide colorimetric assay and the DNA-binding fluorochrome bis (benzimide) trihydro-chloride (Hoechst 33258) staining. The change of ICE protein level in tumor cells during apoptosis was determined by immunoblotting assay. Whether the specific tetrapeptide ICE inhibitor Ac-YVAD-CMK affected gamma-irradiation-induced apoptosis in tumor cells was also examined. The effect of ICE overexpression on tumor cells was evaluated by a transient transfection assay using ICE expression vector. RESULTS: Gamma-irradiation inhibited the cell viability of WERI-Rb-1 and Y79 cells in a dose-dependent manner and induced apoptosis. The protein level of ICE was remarkably enhanced after the treatment. The apoptotic cell death induced by gamma-irradiation was suppressed by the tetrapeptide ICE inhibitor Ac-YVAD-CMK. Moreover, overexpression of ICE induced apoptosis in tumor cells. CONCLUSIONS: These findings suggest that ICE may play an important role in gamma-irradiation-induced apoptosis in retinoblastoma cells. Transfer of the ICE gene induces apoptosis in these cells without gamma-irradiation.

Amino Acid Chloromethyl Ketones↗
PubMed2005

The role of nitric oxide synthases and nitrotyrosine in retinoblastoma.

BACKGROUND: To investigate the potential involvement of the nitric oxide (NO) pathway in retinoblastoma, the authors correlated immunoreactivity for endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and nitrotyrosine (NT) with the degree of tumor invasiveness in retinoblastoma. METHODS: eNOS, iNOS, and NT reactivity was evaluated by immunohistochemistry in 34 archival retinoblastoma specimens and in a human Y79 retinoblastoma cell line. The tumors were divided into 2 groups: Group A tumors (n = 17 tumors) with no invasion and Group B tumors (n = 17 tumors) with invasion of the choroid, optic nerve, and/or orbit. The expression levels of eNOS, iNOS, and NT were correlated with invasiveness of the tumors. RESULTS: In Group A tumors (n = 17 tumors) without invasion, eNOS was positive in 17 of 17 tumors (100%), iNOS was positive in 14 of 17 tumors (82%), and NT was positive in 17 of 17 tumors (100%). In Group B tumors (n = 17 tumors) with invasion, eNOS was positive in 17 of 17 tumors (100%), iNOS was positive in 16 of 17 tumors (94%), and NT was positive in 17 of 17 tumors (100%). The invasive cohort showed significantly higher expression of iNOS (P < 0.0001) and NT (P < 0.020) compared with the noninvasive cohort. Y79 cells also expressed eNOS, iNOS, and NT; and nonneoplastic retina was positive for eNOS, iNOS, and NT. CONCLUSIONS: Taken together, the results suggested that retinoblastomas can produce NO. The roles of NO in the biology of retinoblastoma and in the prognosis for patients with retinoblastoma remain to be established.

Child, Preschool↗
PubMedDate not supplied

Apoptosis after butyrate-induced differentiation in retinoblastoma cell line Y-79.

PURPOSE: To study the fate of Y-79 human retinoblastoma cells after induction of differentiation. METHODS: Y-79 cells were cultured in a synthetic medium and were induced to neuronal differentiation by butyrate treatment. Neurofilaments, p53, and DNA-synthesizing nuclei labeled with 5-bromodeoxyuridine were immunostained, and apoptotic cells were labeled by in situ DNA nick end labeling (TUNEL). We combined these immunostaining and labeling methods to determine whether the cells expressed these markers at the same time. DNA fragmentation and p53 levels were also determined by electrophoresis. RESULTS: Y-79 cells proliferated in the synthetic medium. After butyrate treatment, they extended protrusions and increased neurofilament immunoreactivity. The differentiated features were striking on day 7. Thereafter, differentiated cells decreased and apoptotic cells increased. DNA synthesis was detected in the cells expressing immunoreactivity for neurofilaments or p53. At day 7, most of the cells with p53-positive nuclei were alive and neurofilament-positive. However at day 10, the p53-positive cells were apoptotic and neurofilament-positive apoptotic cells accumulated. CONCLUSIONS: We conclude that the Y-79 cells express p53 and undergo apoptosis after neuronal differentiation. There could be a p53-dependent apoptotic pathway in butyrate-induced differentiated Y-79 cells due to the inability to regulate cell cycling.

Apoptosis↗
PubMedDate not supplied

[Computerized ultrasonic diagnosis of voluminous intraocular neoplasms].

A method of differential diagnostics of voluminous intraocular neoplasms is described; the method is based on the usage of serum-scale scanning, echodensitometry, and vector mode of narrow-strip amplitude filtration (a modification of A-scanning). The digital one-dimension scanning images were subjected to spectral analysis. The obtained results were used alongside with the echodensitometry parameters of echogenicity and homogeneicity as the input data for a subsequent discriminative analysis. A total of 100 scanning images, obtained from 50 patients (50 eyes), with voluminous intraocular neoplasms underwent such analysis: according to its results, the correct diagnosis was made in 97 of 100 cases.

Adolescent↗
PubMed2003

Retinoblastoma associated with chromosomal 13q14 deletion mosaicism.

PURPOSE: To assess the risk of retinoblastoma developing in children with microscopic chromosomal with mosaic deletions involving 13q14. DESIGN: Case report and systematic literature review. PARTICIPANTS: Data on 29 patients with a mosaic and 107 patients with a nonmosaic somatic deletion of chromosome 13q14 were compared. MAIN OUTCOME MEASURES: Age at diagnosis, frequency, and laterality of retinoblastoma. CASE REPORT: A dysmorphic baby, who carried a chromosomal deletion involving 13q14 in 34% of peripheral blood lymphocytes, had neuroradiologic evidence of retinoblastoma at the age of 2 weeks. She developed trilateral retinoblastoma, a pineal neuroblastic tumor, at the age of 10 months. The diagnosis of her tumor was delayed because of misjudgment of risk of retinoblastoma developing. RESULTS: Meta-analysis revealed no difference between children with mosaic and nonmosaic chromosomal deletion of 13q14 regarding the age at diagnosis, laterality of tumor, and presence of family history for retinoblastoma. A lower percentage of somatic cells with mosaic deletion did not predict a higher age at diagnosis or unilateral tumors. No statistically significant difference was noted regarding the presence of mental retardation, dysmorphic features, and anomalies of internal organs between mosaic and nonmosaic deletions. Only 7% (95% confidence interval, 1-23) of 29 patients who had a mosaic chromosomal deletion including 13q14 were not reported to develop retinoblastoma. CONCLUSIONS: Whenever a 13q14 deletion is diagnosed, immediate ophthalmologic evaluation is recommended to ensure prompt diagnosis of retinoblastoma. Mosaic and nonmosaic chromosomal deletions of 13q14 do not differ regarding the risk and type of retinoblastoma developing.

Brain Neoplasms↗
PubMed2004

[Primary intraocular lymphoma with unusual clinical presentation and poor outcome].

BACKGROUND: Primary intraocular lymphoma is a distinct subset of primary non-Hodgkin's lymphoma of the CNS. In general, the primary non-Hodgkin's lymphoma of the CNS is rare, accounting for 1 % of all non-Hodgkin's lymphomas and less than 1 % of all intraocular tumors. HISTORY AND SIGNS: A 70-year-old man was hospitalized in June 2002 because of acute loss of vision on his left eye. A severe vitreous hemorrhage was observed. Ultrasound showed solid subretinal lesions at the posterior fundus. Diagnostic vitreous surgery including a biopsy was performed. An intraocular malignant B-cell lymphoma was determined by immunohistochemistry. General screening revealed no further manifestations of the lymphoma. THERAPY AND OUTCOME: The patient initially refused any therapy until a painful secondary neovascular glaucoma with complete loss of visual function developed, thus prompting us to perform an enucleation. The following immunohistochemical examination confirmed the initial diagnosis. A chemotherapy with high-dose methotrexate and leucovorin rescue was initiated. CONCLUSIONS: Primary intraocular lymphoma can present as diffuse uveitis refractory to corticosteroids. Diagnosis can be difficult and is often delayed.

Aged↗
PubMed1980

Annual review of section on ocular disease: diseases of the optic nerve, tracts, and visual cortex.

The ophthalmic literature dealing with diseases of the optic nerve, tracts, and visual cortex was reviewed for the period November 1977 to December 1978. Fifty-nine papers of interest to optometrists have been abstracted. Main areas of interest include: role of axoplasmic transport in production of disc edema and cotton-wool spots; ocular effects of local and systemic vascular disturbances; congenital abnormalities of the eye alone and in association with other bodily malformation; field testing, including an ingenious ophthalmoscopic method which can lead to detection of very small scotomas; a new quantitative method for assessing integrity of the optic nerve in multiple sclerosis and related conditions; stimulating questions on the development of optic atrophy and on its relation to retinal vascularity; considerations of acquired and congenital abnormalities of the cavernous sinus and their ocular manifestations; swinging-flashlight test in hemianoptic patients; a case of subacute sclerosing panecephalitis; methods to enhance magnification during opthalmoscopy; methods enabling a closer investigation of the retinal nerve fiber layer.

Adolescent↗