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At least 811 records · Page 45Linked to original sources
PubMed2006

[Combined hamartoma of the retina and retinal pigment epithelium. Four case studies].

INTRODUCTION: Combined hamartoma of the retina and retinal pigment epithelium is a rare condition, characterized by a proliferation of the retinal pigmentary epithelium and retinal gliosis leading to a disorganization of the retina and papilla. This study aimed to demonstrate the advantages of early diagnosis and regular monitoring. OBSERVATIONS: We report a series of four children followed between 2001 and 2004 with combined hamartoma of the retina and retinal pigment epithelium, with age of diagnosis ranging from 3 months to 8 years. The main reason for consultation was reduction of vision. The clinical examination objectified the existence of a slightly grayish peripapillary formation with tortuous retinal vessels. This condition was confirmed by angiography with fluorescein in three cases and by optical coherence tomography (OCT) in one case. Progression showed the persistence of low vision in all four cases and the appearance of a neovascular membrane in one case. DISCUSSION: Combined hamartoma of the retina and retinal pigment epithelium is probably a congenital tumor whose pathogenesis has not yet been elucidated. The diagnosis is clinical and the patient can be thoroughly examined by retinal angiography and optical coherence tomography (OCT). In this disorder, it is important to eliminate retinoblastoma and malignant melanoma of the choroid, showing the advantage of radiological exploration. Progression is stationary; nevertheless a reduction in visual acuity can be related to an epiretinal membrane or a neovascular membrane. CONCLUSION: Knowledge of the clinical aspect is essential to differentiate this condition from the malignant retinal processes. This tumor can progress in spite of its benign character. Regular follow-up is essential and can improve the visual prognosis.

Child↗
PubMed2000

[Radioimmunometric assay of neuron specific enolase in aqueous humor and serum in patients with retinoblastoma].

INTRODUCTION: Retinoblastomas (RB) are the most common malignant intraocular tumors in childhood. The neuron specific enolase (NSE) is used as a tumor marker in different malignant diseases (mainly in neuroblastomas and lung carcinoma of small cells). In this work we report our experience using NSE and the role we consider that it plays in the determination of this enzyme in RB cases. MATERIALS AND METHODS: NSE determinations in aqueous humor (AH) and serum were carried out in 17 RB by means of a radioimmunometric assay and were compared with those values obtained in a control group composed of 8 subjects in whom the RB diagnosis as well as other diseases that could alter its determination had been ruled out. The possible correlation between NSE levels and different tumor stages (Reese-Elsworth and histological-clinical), as well as the tumor type (exophytic and mixed) were also studied. RESULTS: NSE levels were increased in AH and serum in 88% of RB patients and were normal in all the subjects in the control group (when a sample which was considered to be non-valid due to the presence of red cells in AH was excluded). No correlation between NSE levels in AH and serum and the different tumor stages was found. Nevertheless, the RB group of mixed tumor type showed a significantly higher mean in AH (p<0.01) than the RB exophytic group. CONCLUSION: NSE determination in AH is of value in the differential diagnosis in patients in whom RB is suspected but difficult to diagnose as well as in the diagnosis of relapses. Serum determinations are mainly useful in the follow-up and in the early diagnosis of possible metastases.

Child, Preschool↗
PubMed1999

Establishment and characterization of a second primary osteosarcoma cell line (OSrb/N-M) from a patient cured of bilateral retinoblastoma.

A cell line, designated OSrb/N-M, was established from the second primary osteosarcoma that developed in a 17-year-old Japanese female patient who had suffered from bilateral retinoblastoma at infancy. The OSrb/N-M cells grew as an adherent monolayer and retained some osteogenic biochemical phenotypes. In cytogenetic analyses, this cell line revealed many structural and numerical abnormalities, however, the bands q14 of both chromosomes 13 appeared to be normal, whereas the constitutional cells displayed normal female karyotypes. Immunoblot studies using monoclonal antibodies specific to RB protein demonstrated that the tumor cells did not express RB protein, suggesting that the OSrb/N-M cells might suffer from a loss-of-function mutation at this gene locus. Thus, this cell line is useful to study the molecular mechanism for the tumorigenesis of osteosarcoma with regard to an association with retinoblastoma.

Adolescent↗
PubMed1997

Optimized lens-sparing treatment of retinoblastoma with electron beams.

PURPOSE: The ideal lens-sparing radiotherapy technique for retinoblastoma calls for 100% dose to the entire retina including the ora serrata and zero dose to the lens. Published techniques, most of which use photons, have not accomplished this ideal treatment. We describe here a technique that approaches this ideal configuration using electron beam therapy. METHODS AND MATERIALS: Dose-modeling calculations were made using a computer program built around a proprietary algorithm. This program calculates 3D dose distribution for electrons and photons and uses the Cimmino feasibility method for the inverse problem of beam weighting to achieve the prescribed dose. The algorithm has been verified in the ocular region by measurements in a RANDO phantom. To search for an ideal lens-sparing beam setup, a stylized phantom of an 8-month-old infant was generated with built-in inhomogeneities, and a phantom of a 5-year-old child was generated from a patient CT series. RESULTS: Of more than 100 different beam setups tested, two 9 MeV electron beams at gantry angles plus and minus 26 degrees from the optic nerve axis achieved the best distribution. Both fields have a lens block and an isocenter between the globe and origin of the optic nerve. When equal doses are given to both fields, the entire extent of the retina (including ora serrata) received 100%, while the lens received 10% or less. CONCLUSION: The two-oblique-electron-beam technique here described appears to meet most of the stringent dosimetry needed to treat retinoblastoma. It is suitable for a range of ages, from infancy to early childhood years.

Algorithms↗
PubMed2002

Segmentation techniques for tissue differentiation in MRI of ophthalmology using fuzzy clustering algorithms.

This paper presents MRI segmentation techniques to differentiate abnormal and normal tissues in Ophthalmology using fuzzy clustering algorithms. Applying the best-known fuzzy c-means (FCM) clustering algorithm, a newly proposed algorithm, called an alternative fuzzy c-mean (AFCM), was used for MRI segmentation in Ophthalmology. These unsupervised segmentation algorithms can help Ophthalmologists to reduce the medical imaging noise effects originating from low resolution sensors and/or the structures that move during the data acquisition. They may be particularly helpful in the clinical oncological field as an aid to the diagnosis of Retinoblastoma, an inborn oncological disease in which symptoms usually show in early childhood. For the purpose of early treatment with radiotherapy and surgery, the newly proposed AFCM is preferred to provide more information for medical images used by Ophthalmologists. Comparisons between FCM and AFCM segmentations are made. Both fuzzy clustering segmentation techniques provide useful information and good results. However, the AFCM method has better detection of abnormal tissues than FCM according to a window selection. Overall, the newly proposed AFCM segmentation technique is recommended in MRI segmentation.

Algorithms↗
PubMed2001

Imaging of the optic nerve and visual pathways.

The visual pathway extends from the globes anteriorly to the occipital cortex posteriorly. A wide variety of disease processes may produce visual dysfunction. Because the optic nerve is a fiber tract of the brain covered by meninges, it can be affected by many of the same pathologic processes that occur in the brain and meninges. Physical examination and diagnostic tests of visual function performed by the clinician can frequently identify the anatomic location of the causative lesion in the patient with vision loss. This enables the radiologist to optimize the imaging evaluation of the patient. This article reviews the normal anatomy of the optic nerve and visual pathways, presents computed tomography (CT) and magnetic resonance (MR) imaging techniques for evaluation of these structures, and discusses the pathologic processes intrinsic to the optic nerve and visual pathways.

Craniopharyngioma↗
PubMed2003

Retinoblastoma and tumor-suppressor gene therapy.

Retinoblastoma as a genetic disease is a paradigm for tumor-suppressor gene theory. The RB gene is one of the best-studied tumor-suppressor genes with known key functions in controlling cell proliferation and differentiation. Reconstitution of RB function in RB-deficient tumor cells induces irreversible growth arrest (senescence) and inhibits telomerase activity, simultaneously correcting two of the four defined carcinogenic events in human cells. RB gene therapy has the advantage of selectively killing tumor cells without adverse side effects to normal somatic cells, and efficacy of the therapy has now been demonstrated in vitro and in immunocompetent mouse models. Most preclinical studies of RB gene therapy reported to date have used RB fragments with enhanced cell growth-suppressing function. The clinical success of RB gene therapy of retinoblastoma, however, requires more innovation in vector development.

Animals↗
PubMed2006

Retinoblastoma with spinal recurrence presenting as spinal cord compression.

Central nervous system (CNS) involvement is not rare in extraocular retinoblastoma, and it is not surprising to find it in view of its route of spread. However, although spinal recurrence presenting as spinal cord compression (SCC) is a form of CNS involvement, it is extremely rare. This report describes two patients with unilateral retinoblastoma with spinal recurrence presenting as SCC. The first patient developed erythematous swelling of the right foot and weakness of the bilateral lower limbs at 7 months after left enucleation. Examination revealed pitting edema of bilateral feet and muscle power of 2+ to 3+, with intact sensory function. The second patient developed weakness of the bilateral lower limbs, and defecative and urinary difficulty for 2 days at 8 months after left enucleation. Examination revealed pitting edema of bilateral feet and muscle power of 2+, with defective sensory function. Both patients received surgery and local irradiation after SCC. The first patient refused chemotherapy and survived only 4 months due to disease progression. The second patient received systemic and intrathecal chemotherapy, and survived 19.5 months without disease progression. Spinal recurrence with SCC should be suspected when leg weakness or bowel or bladder disturbance occurs in patients with retinoblastoma.

Child, Preschool↗
PubMed2000

Retinoblastoma protein in microphthalmic mice.

A microphthalmic strain of mice was used to study immunoresponse of the retinoblastoma protein. Comparing wild-type, heterozygote and homozygote microphthalmic eyes, we found an increasing labelling of phosphorylated retinoblastoma protein (pRb) in the retinal pigment epithelium. Additionally, microphthalmic eyes expressed pRb in the neuroepithelium. Especially rosettes were strongly labelled.

Animals↗
PubMed1998

Loss of delta6-desaturase activity leads to impaired docosahexaenoic acid synthesis in Y-79 retinoblastoma cells.

We have studied the synthesis of docosahexaenoic acid (22:6 n-3) from linolenic acid (18:3 n-3) and eicosapentaenoic acid (20:5 n-3) in Y-79 human retinoblastoma cells and in a derived cell line, Y-79a, which has lost delta6-desaturase activity. Whereas Y-79 cells efficiently converted both radiolabeled 18:3 n-3 and 20:5 n-3 to 22:6 n-3, no synthesis of this fatty acid was observed in Y-79a cells from either 18:3 n-3 or 20:5 n-3. Y-79a cells elongated 18:3 n-3 to 20:3 n-3, which was further converted to 5,11,14,17-20:4 through a delta5-desaturation, elongated 20:5 n-3 to 22:5 n-3 and 24:5 n-3, and retained the ability for retroconversion. These results underscore the key role of delta6-desaturase in the synthesis of 22:6 n-3 and stress the importance of an adequate supply of this fatty acid in situations of reduced delta6-desaturase activity, such as in perinatal period, to prevent a 22:6 n-3 deficiency status.

Docosahexaenoic Acids↗
PubMed1998

Retinoblastoma.

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Chemotherapy, Adjuvant↗
PubMed1998

Age at diagnosis to discriminate those patients for whom constitutional DNA sequencing is appropriate in sporadic unilateral retinoblastoma.

RB1 gene constitutional mutations were studied using 'exon-by-exon' sequencing in a series of 17 patients with sporadic unilateral retinoblastomas. Constitutional de novo germline mutations were detected in 4 patients. The age at diagnosis of retinoblastoma in all these cases was lower (mean 10.8 months; range 5-18) than in cases in which constitutional mutations were not found (mean 31.7 months; range 19-42). These results strongly indicate that age at retinoblastoma diagnosis may be a major factor for discriminating patients for whom a search for RB1 gene constitutional mutations could be justifiable in sporadic unilateral retinoblastomas.

Adolescent↗
PubMed1999

Frequency and nature of germline Rb-1 gene mutations in a series of patients with sporadic unilateral retinoblastoma.

Constitutional Rb-1 gene mutations were studied in a series of 17 families with isolated unilateral retinoblastoma patients. Peripheral blood lymphocytes were analysed by karyotyping, Southern blot hybridisation, and 'exon by exon' sequencing. Mutations were detected in 4 (24%) of the investigated probands. All mutations were identified by sequencing. No alteration was detected by Southern blotting or karyotyping. In one of our cases with a R358 stop codon mutation, retinoblastoma was unilateral at the time of diagnosis, but a tumour of the second eye was diagnosed after 35 months of follow-up. After exclusion of this case, the frequency of constitutional mutations in our series was 19% (3 of 16 cases). Alterations in our cases without involvement of the second eye included G-->A substitution in the promoter region 198 bp upstream of the initiating methionine codon; G-->C transversion in the splice donor site at position +1 leading to exon 6 skipping and a 137 bp in-frame deletion, starting 3 bp from the 5' end of exon 15 to 27 bp from the 3' end of exon 16. All alterations were germline de novo abnormalities.

Blotting, Southern↗
PubMed1998

Eye socket reconstruction with free flaps in patients who have had postoperative radiotherapy.

It is difficult to fit an ocular prosthesis and correct periorbital depression deformity in a patient who has undergone radiotherapy after enucleation of the eye for retinoblastoma during infancy. Simultaneously, developmental disturbances of the eyelids and severe periorbital depression deformities develop. However, due to recent advances in microvascular surgery, free flap transplantation is increasingly used for eye socket reconstruction because of its good circulatory effects with enough volume to augment large periorbital tissue defects. In the present study, we report on our success in using a free groin flap, scapular flaps and parascapular flaps simultaneously for reconstruction of eye sockets and correction of depressed deformities.

Adult↗
PubMed1996

Coats' disease.

A 3-year-old boy had leukocoria in his right eye that could have been confused for retinoblastoma because leukocoria is the most common presenting sign of retinoblastoma. Educating parents, nurse practitioners, pediatricians, and fellow health care professionals about such presenting ocular signs will help expedite ophthalmic examinations and accurate diagnosis for these children.

Child, Preschool↗
PubMed1996

Genetic teaching for the retinoblastoma patient.

Retinoblastoma is the most common primary intraocular tumor in children. Retinoblastoma can be hereditary (familial) or nonhereditary (nonfamilial). Nurses who have an understanding of the genetic patterns for retinoblastoma can participate in the counseling of these patients. A chart is provided as a tool for teaching patients about family patterns of retinoblastoma.

Adult↗