Biomedical subjects

N Bechrakis

Publications and source records attributed to N Bechrakis.

4 recordsLinked to original sources

PubMed2003

[Clinical characteristics of choroidal metastasis].

BACKGROUND: Choroidal metastasis (CM) is the most common malignant intraocular tumor. The aim of this study was the characterization of the ophthalmoscopic aspect, the underlying tumor disease and differential diagnosis of this entity. STUDY DESIGN: Retrospective observational case series. PATIENTS AND METHODS: A total of 71 consecutive patients with CM were evaluated. Special attention was given to ocular symptoms, the ophthalmoscopic and sonographic aspects and the characteristics of the underlying tumor disease. All patients had undergone screening (CCT, CT of thorax and abdomen; bone scintigraphy) for the primary tumor and further organ metastases. RESULTS: Of the patients 95% had symptomatic CM, in 5% of the patients CM was detected by chance, 60% had a single CM, 40% showed multiple (2-14) lesions and 18% ( n=13) had no history of tumor disease. In 12 of these patients lung cancer could be diagnosed. In 53% of the patients the primary tumor was breast cancer, in 26% lung cancer, in 3% kidney cancer, bowel cancer, choroidal or cutaneous melanoma and in single patients cervical, ovarian, thymus or prostate cancer. In one patient who died from disseminated metastases, no definite primary tumor could be detected. Of the patients 96% had further metastases, CM occurred with a mean interval after diagnosis of the primary of 9 months in lung cancer and 68 months in breast cancer. CM was the first clinical sign of tumor disease in 58% of patients with lung cancer and the first clinical sign of metastatic disease in 28% of patients with breast cancer. CONCLUSIONS: Choroidal metastasis occurs almost exclusively in metastatic disease. In breast cancer it typically occurs years after diagnosis of the primary tumor and may be the first sign of metastatic disease. In lung cancer choroidal metastasis may be the first sign of the tumor disease.

Adult↗

PubMed1998

Expression patterns of cyclin D1 and related proteins regulating G1-S phase transition in uveal melanoma and retinoblastoma.

BACKGROUND/AIMS: A checkpoint mechanism in late G1, whose regulation via loss of retinoblastoma protein (pRB) or p16, or overexpression of cyclin D1 or cyclin dependent kinase 4 (CDK4), has been proposed to constitute a common pathway to malignancy. The aims of this study were (a) to compare markers of cell cycle G1-S phase transition in an intraocular tumour with known pRB deficiency (retinoblastoma) and compare it with one with an apparently functional pRB (uveal melanoma); (b) to determine if one of these markers may have a role in the pathogenesis of uveal melanoma; and (c) to determine if there is a difference in cell cycle marker expression following treatment of uveal melanoma and retinoblastoma. METHODS: 90 eyes were enucleated from 89 patients for retinoblastoma (n = 24) or for choroidal or ciliary body melanoma (n = 66). Conventional paraffin sections were assessed for cell type and degree of differentiation. Additional slides were investigated applying standard immunohistochemical methods with antibodies specific for cyclin D1 protein, pRB, p53, p21, p16, BCL-2, and MIB-1. RESULTS: Cyclin D1 protein and pRB were negative in retinoblastoma using the applied antibodies. In contrast, cyclin D1 protein expression was observed in 65% of uveal melanomas; a positive correlation between cyclin D1 cell positivity and tumour cell type, location, growth fraction, as well as with pRB positivity was observed. p53, p21, and p16 could be demonstrated in both tumours. An inverse relation between p53 and p21 expression was demonstrated in most choroidal melanomas and in some retinoblastomas. Apart from a decrease in the growth fractions of the tumours as determined by MIB-1, a significant difference in the expression of G1-S phase transition markers in vital areas of uveal melanoma and retinoblastoma following treatment with radiotherapy and/or chemotherapy was not observed. CONCLUSION: Retinoblastomas and uveal melanomas, two tumours of differing pRB status, differ also in their immunohistochemical pattern for markers of the G1-S phase transition of the cell cycle. The results of the present study support the concept of (a) an autoregulatory loop between pRB and cyclin D1 in tumours with a functional pRB and the disruption of this loop in the presence of pRB mutation, as well as (b) a checkpoint mechanism in late G1, whose regulation via loss of p16 or pRB, or overexpression of cyclin D1 constitutes a common pathway to malignancy. Further, the results raise the possibility of cyclin D1 overexpression having a role in the pathogenesis of uveal melanoma.

Adolescent↗

PubMed1994

Recurrent keratoconus.

Keratoconus is a progressive, noninflammatory, nonvascular axial corneal ectasia, with unclear etiology and pathogenesis. It has a prevalence of 50-230 per 100,000 and is a bilateral disorder in up to 90% of cases. The onset of keratoconus is usually at puberty and progresses over 10-20 years producing an irregular myopic astigmatism. The treatment depends on the severity of the irregular astigmatism. Advanced keratoconus, which cannot be treated with contact lenses, requires a surgical procedure--either penetrating keratoplasty, epikeratophakia, or thermokeratoplasty. The results of penetrating keratoplasty are good, with success rates of > 90% of the cases. Recurrence of keratoconus following penetrating keratoplasty has been previously reported, based on a clinical diagnosis, and confirmed by histopathological examination. We report the clinicopathologic features of two further cases of recurrent keratoconus.

Adult↗

PubMedDate not supplied

Preliminary results of primary chemotherapy in retinoblastoma.

BACKGROUND: Eye retention rates after external beam therapy for advanced retinoblastoma are close to 90% with very few ocular side effects like radiation retinopathy or radiation induced optic neuropathy. Late complications, however, comprise a sixfold increase of secondary non-ocular cancers like soft tissue sarcomas demanding alternative treatment options in the management of advanced retinoblastoma. PURPOSE: A phase I study on primary chemotherapy using vincristine, cyclophosphamide, etoposide and carboplatin in advanced bilateral retinoblastoma was undertaken to evaluate the potential of a treatment regimen not including external beam therapy. PATIENTS AND METHODS: 12 eyes with 17 tumors in 9 children were treated with primary chemotherapy as first treatment option with a mean follow-up of 16.7 months. Planned enucleation of a tumor containing eye was performed in 2 eyes. In one of these enucleated eyes no viable tumor cells were visible on histopathological examination while in the other eye marked tumor regression was detectable. Of the remaining 10 eyes clinical regression of the intraocular tumors was present in all eyes; on average the tumor size was reduced by 50% within 3-6 weeks. Most of the tumors showed a type I (cottage cheese) regression indistinguishable from regression patterns found after external beam radiotherapy. Ancillary treatments including laser photocoagulation, beta-ray brachytherapy, external beam radiotherapy and cryotherapy were performed in 15 out of the 17 tumors. CONCLUSION: Based on the results of this study and on the results published by others primary chemotherapy may result in the same eye retention rate as conventional external beam therapy avoiding the unacceptable high rate of secondary non-ocular cancers in the latter. A prospective study to be undertaken by the GPOH (Gesellschaft für Pädiatrische Onkologie und Hämatologie) and the RG (Retinologische Gesellschaft) is planned to further evaluate this new and promising approach.

Antineoplastic Combined Chemotherapy Protocols↗