[Recommendations for genetic testing and management of individuals genetically at-risk of cutaneous melanoma]. / Recommandations pour le diagnostic de prédisposition génétique au mélanome cutané et pour la prise en charge des personnes à risque.

Cutaneous melanoma is a multifactorial disease resulting from both environmental and genetic factors. Five susceptibility genes have been identified over the past years, comprising high-risk susceptibility genes (CDKN2A, CDK4, and BAP1 genes) and intermediate-risk susceptibility genes (MITF, and MC1R genes). The aim of this expert consensus was to define clinical contexts justifying genetic analyses, to describe the conduct of these analyses, and to propose surveillance recommendations. Given the regulatory constraints, it is recommended that dermatologists work in tandem with a geneticist. Genetic analysis may be prescribed when at least two episodes of histologically proven invasive cutaneous melanoma have been diagnosed before the age of 75 years in two 1st or 2nd degree relatives or in the same individual. The occurrence in the same individual or in a relative of invasive cutaneous melanoma with ocular melanoma, pancreatic cancer, renal cancer, mesothelioma or a central nervous system tumour are also indications for genetic testing. Management is based upon properly managed photoprotection and dermatological monitoring according to genetic status. Finally, depending on the mutated gene and the familial history, associated tumour risks require specific management (e.g. ocular melanoma, pancreatic cancer). Due to the rapid progress in genetics, these recommendations will need to be updated regularly.

FGF23 is independently associated with vascular calcification but not bone mineral density in patients at various CKD stages.

SUMMARY: The hormone fibroblast growth factor 23 (FGF23) is involved in mineral homeostasis but may also have a role in vascular calcification and bone mineralization. In a cohort of 142 patients with CKD stages 2-5D, plasma FGF23 was independently associated with aortic calcification but not with pulse wave velocity or bone mineral density. INTRODUCTION: FGF23 is involved in mineral homeostasis but may also have a role in vascular calcification and bone mineralization. Previous studies related to FGF23 and vascular and bone outcomes have been restricted to dialysis patients. The aim of the present study was to establish whether or not plasma FGF23 is associated with aortic and coronary calcification, arterial stiffness, and bone mineral density in patients with early as well as late stages of CKD. METHODS: In a cohort of 142 patients with CKD stages 2-5D, we made routine biochemistry and intact FGF23 determinations, and assessed aortic and coronary calcification, bone mineral density (BMD), and arterial stiffness by multislice spiral computed tomography and automated pulse wave velocity (PWV). RESULTS: Plasma intact FGF23 levels were elevated in CKD patients; the elevation preceded that of serum phosphate in early-stage CKD. Patients with elevated FGF23 levels had higher aortic and coronary calcification scores than patients with lower FGF23 levels. Multivariate linear regression analysis indicated that only age (p < 0.001) and FGF23 (p = 0.008) were independently associated with aortic calcification score. Plasma FGF23 was neither associated with PWV nor with BMD. CONCLUSION: Our data suggest that plasma FGF23 is an independent biomarker of vascular calcification in patients with various CKD stages including early stages. The association between vascular calcification and FGF23 levels appears to be independent of BMD. It remains to be seen whether this association is independent of bone turnover and bone mass.

Secondary orbital exenteration for conjunctival melanoma: A study of 25 cases.

INTRODUCTION: The treatment of conjunctival melanoma is most often conservative, but exenteration is sometimes necessary in order to achieve local control of the disease. It can be performed as a primary procedure in cases of locally advanced disease or as a secondary procedure after one or more recurrences. No benefit to secondary exenteration on patient survival has been demonstrated to date for conjunctival melanoma, and it is generally considered a palliative procedure. PATIENTS AND METHODS: Single-center retrospective study performed in the ocular oncology department of the Institut Curie (Paris, France). We included all patients who underwent secondary orbital exenteration for conjunctival melanoma between January 2008 and January 2016. RESULTS: Twenty-five patients underwent secondary exenteration for conjunctival melanoma. The maximum number of local recurrences prior to exenteration was six. Metastases occurred in 11 patients after exenteration and were more common when there was a greater tumor thickness on histology, if the tumor had not been treated initially in an ocular oncology center, or if there had been a greater number of local recurrences before the secondary exenteration was performed. Seventy-five percent of patients developed metastases when the exenteration was performed after 5 or 6 local recurrences. CONCLUSION: This study suggests that early secondary exenteration (i.e. after a number of local recurrences less than or equal to 4) may reduce the occurrence of metastases (and therefore improve patient survival) in conjunctival melanoma. Thus, secondary exenteration might be a curative surgery in some patients with recurrent disease.

Episodic Src activation in uveal melanoma revealed by kinase activity profiling.

BACKGROUND: The RAS/RAF/MEK/ERK pathway is involved in the balance between melanocyte proliferation and differentiation. The same pathway is constitutively activated in cutaneous and uveal melanoma (UM) and related to tumour growth and survival. Whereas mutant BRAF and NRAS are responsible for the activation of the RAS/RAF/MEK/ERK pathway in most cutaneous melanoma, mutations in these genes are usually absent in UM. METHODS: We set out to explore the RAS/RAF/MEK/ERK pathway and used mitogen-activated protein kinase profiling and tyrosine kinase arrays. RESULTS: We identified Src as a kinase that is associated with ERK1/2 activation in UM. However, low Src levels and reduced ERK1/2 activation in metastatic cell lines suggest that proliferation in metastases can become independent of Src and RAS/RAF/MEK/ERK signalling. Inhibition of Src led to the growth reduction of primary UM cultures and cell lines, whereas metastatic cell line growth was only slightly reduced. CONCLUSION: We identified Src as an important kinase and a potential target for treatment in primary UM. Metastasis cell lines seemed largely resistant to Src inhibition and indicate that in metastases treatment, a different approach may be required.

Basal cell carcinomas of the eyelid: Results of an initial surgical management.

PURPOSE: Our objective was to assess the results of surgical management of palpebral basal cell carcinomas (BCC) followed by a second line treatment discussed during a Multidisciplinary Team Meeting (MTM). MATERIALS AND METHODS: This retrospective single-centred study includes all surgically-treated basal cell carcinomas of the eyelids between January 2005 and January 2015. After initial surgery, the cases were systematically discussed during a multidisciplinary team meeting in order to assess the need for additional treatment. Data relative to the patient, tumor and management were pulled from the medical record. RESULTS: A total of 171 patients were included, with a mean age of 74 years. Among the patients, 151 underwent pentagonal resection of the tumor, and 20 patients had a superficial excision. After surgical management, 120 patients (70.2%) were considered to have sufficient free margins. The other 51 patients (29.8%) had insufficient margins due to remaining tumor cells (38 patients) or free margins less than 1mm. Among these 51 patients with insufficient margins, 19 received a second surgical treatment, 17 patients received adjuvant radiotherapy, and 15 were followed closely with an intensive biannual follow-up program. No patients were lost to follow-up. With a mean follow-up of 42 months (min. 6 months-max. 128 months), 7 out of 171 patients (4.1%) developed a local recurrence. The mean time between surgical management and recurrence was 24 months. The recurrence rate was higher for the group of patients with a recurrent tumor (11.6%) than for the group of patients referred for initial management (2.8%). Incomplete resection was also associated with a higher recurrence rate (3 recurrences out of 51 patients). DISCUSSION: The management of basal cell carcinomas of the eyelid is first and foremost surgical with the goal of complete resection confirmed by histopathological analysis. The histological analyses (Mohs micrographic surgery, frozen section technic, paraffin fixation) and recommended sizes of the margins can vary in the literature, with recurrence rates from 1.8% to 9.5%. CONCLUSION: In our experience, multidisciplinary management of BCC of the eyelid, including initial macroscopic surgery, histopathological analysis stating the histological type and size of the margins, along with additional treatment discussed in a MTM, allows for a recurrence rate of 4.1%.

Outcomes after surgical resection of lower eyelid tumors and reconstruction using a nasal chondromucosal graft and an upper eyelid myocutaneous flap.

INTRODUCTION: Surgical excision of large malignant lower eyelid tumors may cause important full-thickness eyelid defects. The reconstruction of such defects must restore the physiologic function of the eyelid and also re-establish an acceptable aesthetic result. MATERIALS AND METHODS: We report the outcomes of full-thickness excision of tumors extending over half of the horizontal lid length, followed by reconstruction using a nasal chondromucosal graft (coming from the ipsilateral ala of the nose) and an upper eyelid myocutaneous flap. Histological analysis of the specimen identified the tumor type and surgical margins for each patient. RESULTS: A total of 25 patients were operated using this reconstruction technique between March 2009 and June 2015: 17 basal cell carcinomas, 3 spindle cell carcinomas and 5 conjunctival melanomas (out of which 2 were associated with lentigo maligna). Mean duration of follow-up after surgery was respectively 36, 41 and 17 months for each of these 3 tumor types. We found a single local tumor recurrence and this was a basal cell carcinoma in a xeroderma pigmentosum patient. After surgery, none of the patients had lagophthalmos or ocular surface complications. Only 4 patients had a 1mm scleral show postoperatively; 3 other patients developed a small retraction of the eyelid after adjuvant radiotherapy and a 1mm scleral show occurred. CONCLUSION: In malignant tumors, complete surgical excision with histological margins adapted to tumor type prevents local recurrence in most cases. Our repair strategy of nasal chondromucosal graft and skin-muscle flap for large inferior eyelid defects provides good functional and aesthetic results.

In vitro phototoxicity of glycoconjugated porphyrins and chlorins in colorectal adenocarcinoma (HT29) and retinoblastoma (Y79) cell lines.

BACKGROUND: Retinoblastoma is the most common malignant intraocular tumor in children. The current treatment gives a good vital prognostic but there are several drawbacks to the arsenal of "classical antitumoral" therapies. Photodynamic therapy (PDT) could be an exciting non-toxic and non-mutagenic alternative protocol. METHOD: In this paper, we report about the screening of the in vitro photocytotoxicity of hydrophenylporphyrins and chlorins and their glycoconjugated derivatives in a human retinoblastoma cell line (Y79) and for comparison in a colorectal adenocarcinoma cell line (HT29). RESULTS: Despite lower photodynamic activity than that observed for hydroxylated photosensitizers, in particular Foscan(®) glycoconjugated derivatives display phototoxicity (IC50 2.4-0.05µM ±10%) against Y79 cells with examples of significant intrinsic cytotoxicity. Amongst them the triglucosyl porphyrin 10 is highly photocytotoxic (IC50 0.9µM ±10%) but is fully devoid of cytotoxicity (IC50>15µM). The photoactivity is highly modulated by the presence of a diethyleneglycol spacer between the chromophore and the glycoside (compounds 14-17, IC50 0.5, 0.6, 0.05 and 0.35µM ±10%) and by the anomeric configuration of the sugar (compound 15 and 17, IC50 0.6 and 0.05µM ±10% respectively). One of the main problems for the use of Foscan(®) is its poor solubility which might be improved by glycoconjugation. Moreover Foscan has been shown to induce necrosis after PDT leading to a possible ulceration of surrounding tissues unsuitable for a conservative treatment. A preferential mitochondrial subcellular localization which has been previously reported for some glycoconjugated photosensitizers could enhance the contribution of apoptosis process. CONCLUSION: Tri-α-O-galactosyl porphyrin 16 is a better candidate than Foscan(®) for a clinical application of PDT for a conservative therapy of retinoblastoma.

Evisceration and ocular tumors: What are the consequences?

PURPOSE: Evisceration can be performed for blind, painful eyes. This surgery can promote the dissemination of tumor cells within the orbit if an ocular tumor has been missed preoperatively. METHODS: We reviewed the medical records of patients who were eviscerated for blind, painful eyes between 2009 and 2014 and who were referred after the surgery to the Institut Curie or the Rothschild Foundation in Paris. We included the patients with a histological diagnosis of ocular tumor or orbital recurrence. Cytogenetic analysis was performed whenever possible. RESULTS: Four patients turned out to have an ocular tumor after evisceration (two choroidal melanomas, a rhabdoid tumor and an adenocarcinoma of the retinal pigment epithelium); two had a history of prior ocular trauma. The tumors were diagnosed either on histological analysis of the intraocular contents (2 patients) or biopsy of orbital recurrence (2 patients). Prior to evisceration, fundus examination was not performed in 3 patients. One had preoperative imaging but no intraocular tumor was suspected. At the time of this study, 3 patients had had an orbital recurrence and died. We also found 2 patients who had an evisceration despite a past history of choroidal melanoma treated with proton beam therapy. CONCLUSION: We showed that evisceration of eyes with unsuspected ocular malignancies was associated with a poor prognosis due to orbital recurrence and metastasis. The evisceration specimen should therefore always be sent for histological analysis in order to perform prompt adjuvant orbital radiotherapy if an ocular tumor is found.

Multiplex PCR/liquid chromatography assay for detection of gene rearrangements: application to RB1 gene.

Screening for large gene rearrangements is established as an important part of molecular medicine but is also challenging. A variety of robust methods can detect whole-gene deletions, but will fail to detect more subtle rearrangements that may involve a single exon. In this paper, we describe a new, versatile and robust method to assess exon copy number, called multiplex PCR/liquid chromatography assay (MP/LC). Multiple exons are amplified using unlabeled primers, then separated by ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC), and quantitated by fluorescent detection using a post-column intercalation dye. The relative peak intensities for each target directly reflect exon copy number. This novel technique was used to screen a panel of 121 unrelated retinoblastoma patients who were tested previously using a reference strategy. MP/LC correctly scored all deletions and demonstrated a previously undetected RB1 duplication, the first to be described. MP/LC appears to be an easy, versatile, and cost-effective method, which is particularly relevant to denaturing HPLC (DHPLC) users since it broadens the spectrum of available applications on a DHPLC system.

[Relationship between human immunodeficiency virus (HIV-AIDS) and conjunctival squamous cell carcinoma: A clinical epidemiological study of 26 cases in the ophthalmology department of the university hospital of Treichville-Abidjan (Abidjan-Côte d'Ivoire)]. / Relation entre le virus de l'immunodéficience acquis (VIH-sida) et Carcinome épidermoïde conjonctival (CEC) : étude épidémioclinique de 26 dossiers au service d'ophtalmologie du CHU de Treichville (Abidjan-Cote d'Ivoire).

PURPOSE: To describe the epidemiological and clinical parameters of conjunctival squamous cell carcinomas and their association with HIV-AIDS in the ophthalmology department of the university hospital of Treichville. PATIENTS ET METHODS: This is a prospective and descriptive cross sectional study carried out in the ophthalmology department of the university hospital of Treichville from July 2007 to June 2011. Twenty-six (26) patients who were selected presented with a tumor of the globe and/or adnexa. A CT scan was performed in advanced cases. Histopathological examination of the surgical specimen was performed in all cases. HIV serology was performed after informed consent. All patients were referred to the oncology department of the university hospital of Treichville where a unit of care for HIV-positive patients with malignant tumors is available. Statistical analysis was performed using the software program EPI info version 6.0. RESULTS: We note a slight predominance of female patients 15 (57.69%) vs. 11 (42.3%) male patients. The mean age was 42.32 years, and 13 patients (50%) were between 25 and 45 years of age. Intraorbital tumors were the most common reason for consultation, i.e. 38.46%. Seventeen patients (65.38%) had no particular history. Nine patients (34.61%) were already on antiretroviral treatment on admission. Three patients, i.e. 11.54%, had already had tumor biopsy and/or evisceration. The mean duration of the disease before consultation in ophthalmology was 14.28 months. Localized limbal conjunctival tumors were found in 11 cases (42.38%). Advanced tumors with regional or cerebral extension accounted for 34.61% of cases. Six patients (23.078%) were HIV negative vs. 20 (76.92%) HIV positive patients. CD4 lymphocyte typing was performed in 17 patients (85%), and 45% had a CD4 count below 200. Only five patients were able to receive neoadjuvant chemotherapy, but three of them died. The average length of follow-up was 29 months. COMMENT: This study allowed us to establish a statistically significant link between HIV positive status of patients and the occurrence of squamous cell carcinoma, (P=10(-4)), as well as the decline in CD4 count and disease progression (p=10(-3)). CONCLUSION: The poor prognosis of conjunctival carcinoma reflects the low socioeconomic status of patients, physician under-staffing in our health care facilities, the prohibitive cost of anticancer drugs and the link between this disease and HIV-AIDS.

Conservative treatment of retinoblastoma: a prospective phase II randomized trial of neoadjuvant chemotherapy followed by local treatments and chemothermotherapy.

PurposeIntraocular retinoblastoma treatments often combine chemotherapy and focal treatments. A first prospective protocol of conservative treatments in our institution showed the efficacy of the use of two courses of chemoreduction with etoposide and carboplatin, followed by chemothermotherapy using carboplatin as a single agent and diode laser. In order to decrease the possible long-term toxicity of chemotherapy due to etoposide, a randomized neoadjuvant phase II protocol was conducted using vincristine-carboplatin vs etoposide-carboplatin.Patients and methodsThe study was proposed when initial tumor characteristics did not allow front-line local treatments. Patients included in this phase II noncomparative randomized study of neoadjuvant chemotherapy received vincristin-carboplatin (new arm) vs etoposide-carboplatin (our reference arm). They were subsequently treated by local treatments and chemothermotherapy. Primary end point was the need for secondary enucleation or external beam radiotherapy (EBRT) not exceeding 40% at 2 years.ResultsA total of 65 eyes in 55 children were included in the study (May 2004 to August 2009). Of these, 32 eyes (27 children) were treated in the arm etoposide-carboplatin and 33 eyes (28 children) in the arm vincristin-carboplatin. At 2 years after treatment, 23/33 (69.7%) eyes were treated and salvaged without EBRT or enucleation in the arm vincristin-carboplatin and 26/32 (81.2%) in the arm etoposide-carboplatin.ConclusionEven if the two treatment arms could be considered as sufficiently active according to the study decision rules, neoadjuvant chemotherapy by two cycles of vincristine-carboplatin followed by chemothermotherapy appear to offer less optimal local control than the etoposide-carboplatin combination.

Genome instability in secondary solid tumors developing after radiotherapy of bilateral retinoblastoma.

Genome alterations of seven secondary tumors (five osteosarcomas, one malignant peripheral sheath nerve tumor, one leiomyosarcoma) occurring in the field of irradiation of patients treated for bilateral retinoblastoma have been studied. These patients were predisposed to develop radiation-induced tumors because of the presence of a germ line mutation in the retinoblastoma gene (RB1). Tumor cells were characterized by a high chromosome instability whereas microsatellites and minisatellites were found to be stable. In all tumors, the normal RB1 allele was lost with the corresponding chromosome 13, whereas the germ line mutated allele was retained. The two alleles of TP53 were inactivated, one by deletion of the short arm of chromosome 17, the other by mutation. As compared with non-radiation-induced tumors, the observed panel of TP53 mutations was uncommon with sites not recurrently found otherwise and a high rate of deletions (3/7). In these predisposed patients, the loss of the single normal allele of RB1 is rather due to the radiation-induced chromosome instability than a direct effect of ionizing radiation.

Single-arm study of bridging therapy with low-molecular-weight heparin for patients at risk of arterial embolism who require temporary interruption of warfarin.

BACKGROUND: When warfarin is interrupted for surgery, low-molecular-weight heparin is often used as bridging therapy. However, this practice has never been evaluated in a large prospective study. This study was designed to assess the efficacy and safety of bridging therapy with low-molecular-weight heparin initiated out of hospital. METHODS AND RESULTS: This was a prospective, multicenter, single-arm cohort study of patients at high risk of arterial embolism (prosthetic valves and atrial fibrillation with a major risk factor). Warfarin was held for 5 days preoperatively. Low-molecular-weight heparin was given 3 days preoperatively and at least 4 days postoperatively. Patients were followed up for 3 months for thromboembolism and bleeding. Eleven Canadian tertiary care academic centers participated; 224 patients were enrolled. Eight patients (3.6%; 95% CI, 1.8 to 6.9) had an episode of thromboembolism, of which 2 (0.9%; 95% CI, 0.2 to 3.2) were judged to be due to cardioembolism. Of these 8 episodes of thromboembolism, 6 occurred in patients who had warfarin deferred or withdrawn because of bleeding. There were 15 episodes of major bleeding (6.7%; 95% CI, 4.1 to 10.8): 8 occurred intraoperatively or early postoperatively before low-molecular-weight heparin was restarted, 5 occurred in the first postoperative week after low-molecular-weight heparin was restarted, and 2 occurred well after low-molecular-weight heparin was stopped. There were no deaths. CONCLUSIONS: Bridging therapy with subcutaneous low-molecular-weight heparin is feasible; however, the optimal approach for the management of patients who require temporary interruption of warfarin to have invasive procedures is uncertain.

Etoposide and carboplatin in extraocular retinoblastoma: a study by the Société Française d'Oncologie Pédiatrique.

PURPOSE: A phase II study of etoposide (VP-16) and carboplatin was performed in patients with extraocular retinoblastoma to evaluate the response rate with this drug combination. PATIENTS AND METHODS: Twenty patients with extraocular retinoblastoma, age 9 to 120 months, were included in a cooperative multicenter phase II study of the Société Francçaise d'Oncologie Pédiatrique (SFOP). The schedule consisted of consecutive 5-day treatment with VP-16 100 mg/m2/d and carboplatin 160 mg/m2/d. RESULTS: The response rate for the 20 patients was 85%; there were nine complete responses and eight partial responses. Hematologic toxicity was the only serious observed toxicity and was always manageable. CONCLUSION: This combination of VP-16 and carboplatin is highly effective in extraocular retinoblastoma. The high response rate is encouraging for further evaluation of this drug combination in adjuvant chemotherapy when necessary after enucleation or in neoadjuvant chemotherapy for intraocular tumors.

Prospective study of surveillance testing for metastasis in 100 high-risk uveal melanoma patients.

Despite advances in the local treatment of UM, half of patients develop metastases typically to the liver with poor survival. Microscopic complete surgical resection (R0) of liver metastases improves survival in high selected patients. Early identification of high-risk patients might allow detection of asymptomatic metastases, and increase R0 liver surgery rate. From October 2006 to December 2009, we conducted a prospective study to detect early minimal lesions with 6-monthly liver function tests (LFTs) and liver MRI in 100 high-risk patients. High risk was defined by primary tumor clinical or genomic criteria: thickness>8mm or diameter>15 mm, or extra-scleral extension, or monosomy 3 by FISH or aCGH. With a median follow-up of 49 months, the 5-year metastasis-free survival and overall survival were 47 and 33%, respectively. Of the 60 patients who became metastatic, 50 (83%) had exclusive liver metastasis. LFTs screening had no sufficient accurary, but biannual MRI showed high predictive value to detect metastasis and select patients eligible for curative surgery: 25/50 underwent laparotomy and among them, 8/25 (32%) had a R0 surgery. Median survival after metastasis was 14 months, mean survival reached 40 months in the R0 resected population. Six-monthly liver MRI screening is recommended in patients with large tumors or genomic high risk in order to detect early patient candidates to complete resection of liver metastases.

Treatment of retinoblastoma: The Institut Curie experience on a series of 730 patients (1995 to 2009).

INTRODUCTION: To describe the results of retinoblastoma treatment from 1995-2009 in a single institution. MATERIAL AND METHODS: Retrospective review of the charts of patients treated for retinoblastoma. Clinical characteristics at diagnosis, treatments and outcomes in terms of survival and ocular preservation are described. RESULTS: During the study period 826 children were referred for retinoblastoma and 730 were managed in our institution. Four hundred and eleven children presented with unilateral retinoblastoma and 319 with bilateral retinoblastoma. Median follow-up is of 93 months. Global survival is 98.5% of children, 10 children presented with second tumors, 11 children died (6 of tumor-related causes). Of the 411 children with unilateral retinoblastoma enucleation was needed at diagnosis for 324 (78.8%). Conservative treatments were attempted for 87 patients (21.2%) and ocular preservation obtained for 65 patients (74% of eyes). Three hundred and nineteen patients presented with bilateral retinoblastoma. Three hundred and ten could be treated conservatively for at least one eye. Initial intravenous chemotherapy was necessary for 75% of them. Ocular preservation without external beam radiation was possible for 221 patients (70%). The use of EBR decreased significantly after 2004 (9.1% of eyes vs 25.1%: P<0.001). DISCUSSION: Management and treatment of retinoblastoma are complex, adapted to the extent of the disease. Survival is good. Enucleation is still required for extensive ocular disease, especially for unilateral patients. Intravenous chemotherapy allows good tumor control and eye preservation and decrease the need of EBR. CONCLUSIONS: Retinoblastoma treatment with intravenous chemotherapy and ocular adjuvant therapies is very effective on the local tumor control and eye preservation.

Interleukin-1 beta is a potent inhibitor of bone formation in vitro.

The effect of interleukin-1 beta, the major component of osteoclast-activating factor (OAF), on bone formation by fetal rat osteoblast-rich cells was investigated. An in vitro culture system developed by Ecarot-Charrier et al. (1983) and Bellows et al. (1986) was utilized in which osteoblasts form mineralized nodules which closely resemble woven bone. Continuous exposure of cultures to homogenous IL-1 beta resulted in potent inhibition of mineralized nodule formation, which was half maximal at 0.1 U/ml (7.5 X 10(-13) M). Bone formation may thus be considerably more sensitive to IL-1 beta than is bone resorption (half maximal at 3.8 X 10(-11) M). Inhibition of bone formation occurred when cultures were exposed to IL-1 beta at both early and late time periods and was unaffected by the presence of indomethacin or by the osteoclast inhibitors calcitonin and gamma-interferon. Instead, IL-1 beta exerted multiple inhibitory effects on osteoblast functions, including inhibition of collagen and noncollagen protein synthesis, alkaline phosphatase expression, and cell replication. On a dose response basis, the inhibition of protein synthesis correlated most closely with inhibition of bone formation. IL-1 beta is clearly inhibitory rather than stimulatory for bone formation as assessed in this system and is therefore unlikely to function as a coupling factor linking the processes of bone resorption and bone formation.

Comprehensive screening for constitutional RB1 mutations by DHPLC and QMPSF.

Constitutional mutations of the RB1 gene are associated with a predisposition to retinoblastoma. It is essential to identify these mutations to provide appropriate genetic counseling in retinoblastoma patients, but this represents an extremely challenging task, as the vast majority of mutations are unique and spread over the entire coding sequence. Since 2001, we have implemented RB1 testing on a routine basis as part of the clinical management of retinoblastoma. As most screening techniques do not meet the requirements for efficient RB1 testing, we have devised a semi-automated denaturing high-performance liquid chromatography (DHPLC) method for point mutation detection combined with a quantitative multiplex PCR of short fluorescent fragments (QMPSF) approach to screen for gene rearrangements. We report the results of this comprehensive screening of all exons and promoter of RB1 in 192 unrelated patients, mostly of French origin. Among 102 bilateral and/or familial cases and 90 unilateral sporadic probands, mutations were identified in 83 (81.5%) and 5 (5.5%) cases, respectively. A total of 43 mutations have not been previously reported. The mutational spectrum was found to be significantly different from previous published series, displaying a surprising amount of splice mutations and large deletions. This study demonstrates the reliability of DHPLC for RB1 analysis, but also illustrates the need for a deletion scanning approach. Finally, considering the benefits to retinoblastoma patients, RB1 testing should be widely implemented in routine healthcare because our study clearly illustrates its feasibility.