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PubMedDate not supplied

Ketamine anaesthesia for young children undergoing radiotherapy.

Young children with radiosensitive malignant tumours often require sedation or anaesthesia to provide immobility for radiotherapy sessions lasting several days. This paper describes the use of repeated intramuscular ketamine anaesthesia for radiotherapy in children age 1.5 to 5 years. Intramuscular ketamine 5-13mg/kg body weight was administered on 280 occasions to 15 children, the highest number of sessions per child being 30 and the least 9. The airway and cardiovascular parameters were well maintained. The time to complete recovery varied from 15 to 90 minutes (mean 52.5+/-31.7 S.D.). Involuntary movements of the tongue, mouth and limbs were observed in 8 patients (52.3%) during 63 sessions (22.5%) but only necessitated interruption of radiotherapy on 6 occasions (2.1%). Ketamine was found to be safe and effective for sedation of young children in the radiotherapy suite and minimal aneasthetic facilities were required.

Age Factors↗
PubMed1999

[The status of p53 gene in the primary retinoblastoma].

OBJECTIVE: This study was designed to investigate whether development or progression of retinoblastoma is related with p53 gene mutation. METHODS: A total of 52 cases with primary retinoblastoma were investigated for p53 gene point mutations. To do this, entire coding sequence, including exon 2 - 11, and their vicinity intron sequence were examined by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis followed by direct genomic DNA sequencing. RESULTS: Only did the polymorphisms, silent mutations and variants in intron have been shown in p53 gene, no real p53 gene mutation was found in retinoblastoma no matter the tumor carried Rb gene mutation or not. CONCLUSION: The evidence provided here indicates that the development or progression of retinoblastoma is not associated with p53 gene mutation.

Genes, Retinoblastoma↗
PubMed1999

[A study of expression of p53, c-myc and PCNA in retinoblastoma].

OBJECTIVE: To investigate the expressions of p53, c-myc (oncogene) and proliferating cell nuclear antigen (PCNA) in retinoblastoma (Rb) and the relationships of the expression to the degree of differentiation and optic nerve infiltration. METHOD: The expressions of p53, c-myc and PCNA in Rb tissues of 31 cases were analyzed by using LSAB immunohistochemical method. RESULTS: The positive rates of p53, c-myc and PCNA in Rb were respectively 51.6%, 45.2% and 67.7% and all the expressions were significantly related to the differentiation degree of Rb (all P < 0.05). The expression of PCNA was significantly related to the optic nerve infiltration of Rb (P < 0.05). Both the expressions of p53 and c-myc in Rb were markedly correlated with the expression of PCNA (all P < 0.05). CONCLUSIONS: The occurrence of Rb is the result of multiple gene mutations. The determinations of p53, c-myc and PCNA are of significance for evaluating the histologic characteristics and biological behavior of Rb.

Child, Preschool↗
PubMed2002

Structure and function of the N-cadherin/catenin complex in retinoblastoma.

PURPOSE: To identify in human retinoblastoma and normal retinal tissue the type of cadherin, its relationship with cytoplasmic catenins, and its participation in invasion. METHODS: The cadherin/catenin complex was characterized in surgical retinoblastoma specimens from five patients and human retinas from four donor eyes by immunocytochemistry, flow cytometry, and coimmunoprecipitation with antibodies against N-cadherin, alpha-catenin, and beta-catenin, followed by Western blot analysis or autoradiography. Y79 and WERI-Rb-1 retinoblastoma cell lines serve the evaluation of the cadherin/catenin complex in aggregation and collagen type I invasion in vitro. The association of the cadherin/catenin complex with the cytoskeleton was examined by an antibody-capping assay. RESULTS: In retinoblastoma and normal retina N-cadherin associated with alpha-catenin and beta-catenin but not E- or P-cadherin. The N-cadherin/catenin complex formed a regular, linear, and continuous honeycomb pattern in normal retina that was irregular, clustered, and interrupted in retinoblastoma. The N-cadherin/catenin complex was found also in the retinoblastoma cell lines WERI-Rb and Y79, in which it also showed an irregular pattern. Both cell lines were invasive in collagen type I, and invasion was inhibited by the GC-4 antibody, which functionally neutralizes N-cadherin. Less GC-4 antibody was needed to inhibit invasion of Y79 cells, which expressed N-cadherin at a lower level, than to inhibit invasion of WERI-Rb-1 cells. In both cell lines, antibody capping of the N-cadherin/catenin complex indicated that its linkage with the cytoskeleton were weak or absent. CONCLUSIONS: Retinoblastoma cells, in contrast with normal retina, express an N-cadherin/catenin complex that is irregularly distributed and weakly linked to the cytoskeleton. In retinoblastoma, this complex acts as an invasion promoter.

Autoradiography↗
PubMed1998

[Assessment of six drug sensitivities in established cell lines of SO-Rb50 and SO-Rb70].

OBJECTIVE: With retinoblastoma (Rb) cell lines cultured in vitro to screen chemotherapeutic drugs that are effective on Rb. METHOD: Sensitivity experiments were performed with the 3, -4, 5 Dimethyliazol-2, 5 diphenyl tetrazolium bromide (MTT) assay for the drugs: dactinomycin (DACT), vincristine (VCR), VM-26, daunorubicin (DNR), DDP, bleomycin (BLMA5) against the tumor cell lines of SO-Rb50 and SO-Rb70. RESULTS: The IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb50 were respectively 0.0004, 0.0016, 0.0389, 0.047, 0.29, 0.44, and those at 72 hours were 0.00025, 0.00081, 0.0151, 0.0192, 0.097, 0.11. And the IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb70 were respectively 0.00065, 0.00149, 0.0282, 0.043, 0.37, 0.215, and those at 72 hours were 0.00042, 0.00082, 0.0146, 0.0176, 0.035, 0.084. CONCLUSION: The tumor cell lines of SO-Rb50 and SO-Rb70 were sensitive to the above six pharmaceuticals. By their IC(50) values, the sensitivity order to the drugs, from higher to lower, was DACT, VCR, VM-26, DNR, DDP, BLMA5.

Antineoplastic Agents↗
PubMed1998

[The determination of neuron-specific enolase of serum in the diagnosis and supervision of retinoblastoma].

OBJECTIVE: To investigate the value of determining quantity of neuron-specific enolase (NSE) in the diagnosis and supervision in patients with retinoblastoma (Rb). METHOD: We used rapid electrophoretic and the fluorometer method in the 35 serum specimens from 35 patients with Rb during surgery, after enucleation, respectively, at 3, 6, 12, >or= 18 months and 31 serum specimens from 31 control cases to determine the quantity of NSE and enolase isoenzymes. RESULTS: There were 207 +/- 65.9 u/L of all isoenzymes and 98.4 +/- 40.3 u/L of NSE from 35 patients with Rb. In comparison with the levels of control cases (respectively, 140.7 +/- 46.0 U//L of all isoenzymes, 41 +/- 10.9 u/L of NSE), both serum levels in patients with Rb increased obviously, the difference being significant. At 6, 12, and >or= 18 months after surgery, the determinations of all isoenzymes and NSE from 35 patients with Rb decreased step by step, the difference being significant in comparison with the values before the surgery. After surgery >or= 18 months, the levels of NSE and all enolase decreased to that of NSE and all enolase from control cases. CONCLUSION: The determination of enolase level, especially NSE of serum, is valuable for the diagnosis of patients with Rb.

Child↗
PubMed2002

[Changing perception of hereditary eye diseases].

The authors present the cases of two parents with Usher syndrome type I who appeared to have normal offspring, and two families, one with autosomal dominant retinoblastoma and a RB1-gene mutation and one with primary open angle glaucoma and a myocilin gene mutation, in whom DNA-analysis was used to see whether check-ups were needed. The field of ophthalmogenetics comprises many disorders, both congenital and those with a later onset. Mendelian, mitochondrial, as well as multifactorial heredity is seen. Recent progress in this field, especially in molecular genetics, has created new possibilities, but some situations appear to be more complex than previously assumed. Particularly if there is genetic heterogeneity or multifactorial inheritance, possibilities for counselling and DNA analysis remain limited.

Adult↗
PubMedDate not supplied

[Molecular diagnosis of retinoblastoma. First experience in Russia].

The first experience with molecular diagnosis of retinoblastoma (RB) in Russia is presented. A protocol based on the use of up-to-date molecular diagnostic methods helps detect structural and functional abnormalities in RB1 gene, diagnose RB in disputable cases and at early stages of the disease. Forty-five families with various forms of RB were examined. Twenty-three mutations in various sites of RB1 gene were characterized. Abnormal methylation in the promotor area of RB1 gene was detected in 20% cases and loss of heterozysity by intragene microsatellite markers was detected in 70% cases. Hence, the causes of RB were detected in 80% families, which led to early diagnosis in close relatives of patients and helped evaluate the repeated risk of the tumor in families of patients with RB.

DNA Methylation↗
PubMedDate not supplied

Association between telomerase activity and basic fibroblast growth factor up-regulation in retinoblastomas.

BACKGROUND: Telomerase is an enzyme associated with cellular immortality and malignancy in many cell types. On the other hand, growth factors such as basic fibroblast growth factor (bFGF) or platelet-derived growth factor (PDGF) promote tumor growth, whereas the association between telomerase and these growth factors remains unclear. MATERIALS AND METHODS: Telomerase activity and expression of bFGF and PDGF were assayed in 9 retinoblastoma tissues and 2 cell lines (WERI-Rb-1 and Y79). The association of telomerase activity with bFGF or PDGF was investigated. RESULTS: Telomerase activity was detected in three out of nine tissues and both cell lines. Two telomerase highly-positive tissues and WERI-Rb-1 and Y79 cells expressed bFGF. As for the expression of PDGF, only one retinoblastoma tissue with high telomerase was positive. To further determine whether telomerase activity and bFGF are closely associated, we inhibited each expression. Inhibition of telomerase in WERI-Rb-1 cells using the anti-sense treatment suppressed the expression of bFGF and subsequently induced apoptosis after 25 to 30 doublings. When bFGF expression was suppressed by the neutralizing antibody, telomerase activity was not affected nor was apoptosis detected. CONCLUSION: Telomerase may up-regulate the expression of bFGF and protect retinoblastoma cells from cell death, indicating, the possibility that inhibition of telomerase is a promising approach for the treatment of telomerase-positive tumors.

Antibodies↗
PubMed2001

[Prognosis of retinoblastoma. Report of 50 cases].

PURPOSE: The aim of this study was to analyze the factors influencing the prognosis of retinoblastoma. MATERIALS AND METHODS: In 50 children with retinoblastoma, 69 eyes were reviewed. All patients had a full ophthalmic examination, a B-scan ultrasound, a computerized tomography scan and a pediatric examination. We performed enucleation in 47 eyes (with a histopathological study), external beam irradiation in 16 eyes, curitherapy in 4 eyes, cryotherapy in 3 eyes, and adjuvant chemotherapy in 7 cases. RESULTS: The global survival rate was 87.5%. The main aggravating factors were: the size of the tumor and the extraretinal involvement with extension within the chroid, the sclera, and the optic nerve. CONCLUSION: The prognosis of retinoblastoma mainly depends on the extraretinal invasion.

Child↗
PubMed2002

[New strategies in the management of retinoblastoma].

It was rare that a child survived retinoblastoma at the beginning of the twentieth century. Today the survival rate is in the order of 95% in reference centers, with new strategies improving prognosis step by step. Systematic enucleation used to be the starting point of any true and structured management, until the advent of radiotherapy made it possible not only to save lives but also to retain some useful vision. Early diagnosis has enabled focal therapies such as photocoagulation, cryocoagulation, and radioactive applicators to open up a new era of targeted tumor treatment. However, the onset of nonocular tumors secondary to radiotherapy, the resistance of certain tumors to irradiation, and unsightly cosmetic consequences all justify research into alternative therapeutic strategies. New types of chemotherapy have shown spectacular results and are currently under study: chemoreduction to make large tumors more manageable and enable less aggressive treatment of tumors located in delicate sites, thermochemotherapy using the effect of heat on plasma membrane permeability to antimitotics, and chemotherapy associated with cyclosporine to reduce the multidrug resistance of certain tumors. The aim is to avoid primary enucleation and external beam radiation as far as possible. The future may lie in local chemotherapy, hyperthermia, and dynamic phototherapy, accelerated proton beam radiotherapy also has promising prospects.

Antineoplastic Agents↗
PubMedDate not supplied

Paramacular Von Hippel angioma with tractional macular detachment.

A rare case of paramacular angioma with tractional macular detachment that was managed successfully with laser, followed by surgical intervention with good visual outcome, is presented. A 23-year-old female patient with paramacular Von Hippel angioma was treated with argon laser photocoagulation. Three-months following photocoagulation, vitrectomy with epiretinal tractional membrane removal was attempted successfully. Visual acuity improved from a preoperative level of 20/200 to 20/50 at the 6 months postoperative period. No recurrence of epiretinal membrane or exudation was observed during the follow-up period. Photocoagulation, followed by surgical intervention for removal of epiretinal traction membranes, resulted in relieving the tractional macular detachment and recovering useful visual acuity in paramacular Von Hippel angioma.

Adult↗
PubMed2002

Effect of protein kinase Cgamma on gap junction disassembly in lens epithelial cells and retinal cells in culture.

PURPOSE: To determine the effects of protein kinase Cgamma (PKCgamma) on phosphorylation of Cx43, the gap junction protein of lens epithelial cells, and on cell surface assembly/disassembly of Cx43-gap junction complexes. METHODS: Association and phosphorylation of Cx43 by PKCgamma was determined using co-immunoprecipitation and reaction with phosphoserine antisera. Activation of PKCgamma was with 200 nM phorbol ester for 30 to 60 min. Effects of specific PKC isoforms was determined after overexpression of either PKCalpha or PKCgamma for 24 h in N/N 1003A rabbit lens epithelial cells or in two retinal cell lines, WERI and Y79. Gap junction plaques were counted on the cell surface by immunolabeling of Cx43 using confocal microscopy. RESULTS: Co-immunoprecipitation of Cx43 with PKCgamma was observed only in cells over expressing PKCgamma and in cells activated with phorbol ester. Both overexpression and phorbol ester produced a rapid phosphorylation of Cx43 on serine. Cx43 cell surface gap junction plaques decreased in cells over expressing PKCgamma and in cells treated with phorbol ester. Similar results were observed using the retinal cell lines, WERI and Y79. The effect of PKCgamma overexpression was persistent for 7 days but total cell Cx43 was not decreased. Overexpression of PKCa resulted in an increase in cell surface gap junction plaques. CONCLUSIONS: PKCgamma can be co-immunoprecipitated with Cx43 from lens epithelial cells using phorbol ester activation. PKCgamma phosphorylates Cx43 on serine and this causes disassembly and loss of gap junction Cx43 from the cell surface. Overexpression of PKCgamma confirmed that only this PKC isoform caused the loss of cell surface Cx43. Overexpression of PKCalpha, the other major lens PKC isoform, caused an increase in cell surface Cx43. The presence of PKCgamma and loss of surface Cx43 from two retinal cell lines, WERI and Y79, upon phorbol ester activation further suggests that activation of PKCgamma may be a common mechanism for control of cell surface Cx43.

Animals↗
PubMed2002

Induction of VEGF gene expression by retinoic acid through Sp1-binding sites in retinoblastoma Y79 cells.

PURPOSE: Vascular endothelial growth factor (VEGF) is an angiogenic peptide that has been implicated in many retinopathies. Although all trans-retinoic acid (atRA) has long been known as an essential factor in the visual cycle, the role of atRA in the pathogenesis of retinal disease remains elusive. In this study, we investigated the effects of atRA on expression of the VEGF gene in retinoblastoma Y79 cells. METHODS: Total RNA prepared from Y79 cells, with or without atRA, was subjected to Northern blot analyses. Reporter constructs consisting of the VEGF promoter-luciferase gene were transfected into Y79 cells. Nuclear factors binding to the VEGF promoter were analyzed by electrophoretic mobility shift assays (EMSAs). RESULTS: The levels of VEGF transcripts were increased by atRA in a time- and dose-dependent manner. Progressive deletion and site-specific mutation analyses indicated that atRA increased VEGF promoter activity through a G+C-rich sequence that was shown to be an Sp1-binding site by supershift assays. EMSAs showed that Sp1 binding was increased by atRA stimulation. Although no measurable change was observed in Sp1 mRNA levels, Western blot analysis showed an increase in Sp1 protein levels in the atRA-treated cells. These data suggest that atRA increases Sp1 protein levels by posttranscriptional mechanisms, and elevated levels of Sp1 protein induce the expression of VEGF at the transcriptional level. CONCLUSIONS: atRA induced transcription of the VEGF gene through Sp1-binding sites in Y79 cells. Pharmacologic intervention that inhibits the signals elicited by atRA may be effective in treating VEGF-mediated retinopathies.

Antineoplastic Agents↗
PubMed2002

Retinoic acid upregulates cone arrestin expression in retinoblastoma cells through a Cis element in the distal promoter region.

PURPOSE: This study was initiated to investigate the molecular mechanisms of activation of expression of the human cone arrestin (hCAR) gene by retinoic acid (RA), in an in vitro model of retinoblastoma cells. METHODS: Human retinoblastoma Weri-Rb-1 or Y79 cell lines were cultured in the absence or presence of RA analogues with transcription or translation inhibitors for various periods. The mRNAs encoding hCAR, retinoic acid receptor (RAR), and retinoid X receptor (RXR) subtypes were analyzed by Northern blot. Immunoblot analysis of hCAR protein was also performed. The hCAR promoter's activity and its responsiveness to RA treatment was evaluated by transient transfection of the hCAR promotor-luciferase reporter constructs, followed by promoter deletion analysis to map the specific regions responsible for the RA response. RESULTS: In our in vitro model, both all-trans RA and 9-cis RA induced hCAR mRNA in a time- and dose-dependent manner. RA's effect was blocked by either RNA or protein synthesis inhibitors; however, hCAR mRNA's stability was not affected by RA, as determined by RNA decay experiments. Although all RAR and RXR subtypes were detected, only RXRgamma and RARalpha increased dramatically after treatment with RA. An RXR-specific agonist, but not an RAR-specific agonist, also increased hCAR mRNA and protein expression in both Weri-Rb-1 and Y79 cells. RA stimulated hCAR promoter-luciferase activity in transient transfection studies. Subsequently, a region between -852 and -702 of the hCAR promoter, with RA-responsive elements (RAREs), was discovered to be responsible for the RA response. CONCLUSIONS: The hCAR gene is transcriptionally upregulated by RA acting through cis elements within -852 to -702 of the hCAR 5' flanking region. Based on the cumulative data, RXRgamma is most likely the RA receptor subtype involved in hCAR regulation by RA.

Arrestins↗
PubMedDate not supplied

[Results of combined chemotherapy and local ophtalmic therapy of children with intraocular retinoblastoma].

Until recently chemotherapy in retinoblastoma was used as adjuvant therapy after enucleation in cases with extraretinal spread of the disease (weal extension, orbital extension, neoplastic infiltrates of the optic nerve at resection line, intracranial metastasis and generalized disease). Recent experience has proved that use of chemotherapy for intraocular retinoblastoma before local treatment (so called "chemoreduction") has allowed not only to decrease the number of enucleations and indications for external beam irradiation or limit the extension of local therapy; but also to increase the chances for vision preservation and to decrease the risk of severe complications. Twenty children aged 0,5-96 months (with lesions in 29 eyes) in whom intraocular retinoblastoma was diagnosed between January 1996 and June 2000, were the subject of this study. Among 29 children, in 15 (52%) stage V according to Reese-Ellsworth was established. Enucleation before chemotherapy was necessary in 9 cases, and in two more children the eye had to be removed after 1-2 courses of chemotherapy. In 11 remaining children (with 18 involved eyes) VEC chemotherapy combined with delayed local therapy (cryotherapy, photocoagulation, brachytherapy) was employed. Out of 18 treated cases enucleation could be avoided in 13 (72%), including 12 qualified as Reese-Ellsworth stage II or I. No eye with stage V could be saved. First-line chemotherapy combined with local treatment should be standard treatment for intraocular retinoblastoma groups I and II. More effective therapy is required for advanced cases particularly for Reese-Ellsworth eye group V.

Antineoplastic Combined Chemotherapy Protocols↗