Prevalence and types of aggressive behaviour among adults with intellectual disabilities

BACKGROUND

Aggressive behaviours represent major obstacles to the integration into society of individuals with intellectual disability (ID) and pose significant management issues for carers.

METHODS

The present study assessed the prevalence and severity of five types of aggressive behaviours in 3165 adult men and women with ID receiving services from three rehabilitation agencies in Québec by surveying their carers using the Modified Overt Aggressive Scale.

RESULTS

The 12-month prevalence of aggressive behaviour was 51.8%: 24% property damage, 37.6% verbal, 24.4% self-oriented and 24.4% physical aggression, and 9.8% sexually aggressive behaviour, most of which being mild in severity. Only 4.9% of individuals displayed aggressive behaviour leading to injury of the victim. Few gender differences were observed.

CONCLUSIONS

The capacity to document and assess the types as well as the severity of aggressive behaviour is thus critical, not only to better understand the correlates of various types of behaviours but also to orient intervention programmes whether they be prevention, assessment, monitoring or management of aggressive behaviour.

Phase II trial of temozolomide and cisplatin followed by whole brain radiotherapy in non-small-cell lung cancer patients with brain metastases: a GLOT-GFPC study

BACKGROUND

Brain metastases (BM) considerably worsen the prognosis of non-small-cell lung cancer (NSCLC) patients. The usefulness and choice of chemotherapy remain uncertain in this indication since these patients are excluded from most clinical trials. We conducted a phase II study to determine the efficacy and tolerability of up-front chemotherapy with association of temozolomide and cisplatin in NSCLC patients with BM.

PATIENTS AND METHODS

Fifty NSCLC patients with BM received temozolomide (200 mg/m(2)/day for 5 days every 28 days) and cisplatin (75 mg/m(2) at day 1 of each cycle), up to six cycles, followed by whole brain radiotherapy (WBRT). An evaluation was carried out every two cycles and after WBRT. WBRT was performed earlier in case of progressive disease at any time or stable disease after cycle 4.

RESULTS

Eight objective responses were achieved (16%). Overall median survival was 5 months. Median time to progression was 2.3 months. Ten patients (20%) presented a grade 3/4 neutropenia and 11 patients (22%) presented a grade 3/4 thrombopenia.

CONCLUSION

This study demonstrates a lack of efficacy of up-front chemotherapy with association of temozolomide and cisplatin in these patients. Nevertheless, it supports the feasibility of chemotherapy before brain radiotherapy in NSCLC patients with BM.

Implication of clinical and paraclinical covariates in the pharmacokinetics of high dose MTX (HD-MTX) in patients with osteosarcoma

12022

Background: Methotrexate (MTX) is a mainstay in the treatment of ostosarcoma. MTX is characterized by a narrow therapeutic window, combined with high intra- and inter-patient variabilities. In our institute, safe administration of high dose MTX is ensured by using bayesian, adaptive dosing with feedback strategy. In patients with osteosarcoma, up to 20g/patient MTX is administred following an 8h infusion. From the 6th hour, the dose is tailored according to individual pharmacokinetics parameters, determined in real-time from two early sampling times (T3.5, T4.5) and a reference population. This method enables accurate adjustment of most patients around a target Cend of 10−3 M/L. Still, 15–20% of the patients show reduced MTX elimination rate, thus leading to an overlasting hospitalization time with folate rescue required to prevent severe toxicities. In this work, we studied the relevance of clinical or pareaclinical covariates likely to be associated with the MTX clearance so as to identify patients at risk of impaired elimination with subsequent increase in iatrogeny. Methods: This retrospective study was performed on 49 patients treated with HD-MTX. Population PK parameters were computed using Apis and NonMem routines. The second objective was to predict for how long MTX plasma concentration would remain above 0.2 μM/L, the threshold associated with toxicity, upper which folinic acid is required. Finally, simplified sampling strategy for folate rescue protocol was developed. Results: two covariates (creatinemia and ALAT) have been identified as being correlated with MTX clearance. Besides, simulation of the 0.2μM/L threshold reaching showed that it was possible to predict accurately the time most patients can leave the hospital safely. This, would have led to reduce the hospitalization stay by at least one day in 25% of the patients, thus optimizing their life quality while being cost-effective. Conclusions: in this study, we showed that high dose MTX can be administred safely using an adaptive dosing with drug monitoring strategy. Besides, modelling of MTX PK parameters leads to an accurate estimation of the elimination pattern of this drug, thus enabling a planification of the time patients leave the hospital.

No significant financial relationships to disclose.

Population pharmacokinetic of total cisplatinum: Application to adaptative dosing with feed back in testicular cancer patient

2043

Background: Cisplatinum (CDDP) is major drug used in germ cell testicular cancer. Pharmacokinetics (PK)/pharmacodynamics relationships have been described after measurement of free CDDP in plasma, and subsequently, CDDP administration is standardized using body surface area (BSA) for only dose tailoring. Methods: Based on a rapid assay of total CDDP in plasma we have developed an alternative 120-hours continuous infusion schedule, coupled to a Bayesian adaptive dosing strategy. We present a retrospective evaluation of this schedule in 19 patients (66 courses) treated for testicular germ cell tumors. A NONMEM analysis was then performed to identify the covariates associated with total CDDP clearance. We compared doses effectively given to our patients with the ones calculated with BSA. Results: Plasma samples were analyzed to allow real-time Bayesian estimation of individual PK parameters with subsequent daily dose adjustment in order to reach a target Cend of 1.95 mg/l of total platinum. No statistical difference was observed between experimental and target values, and Cend adjustment was achieved with an overall 6.6% precision, a performance to be compared with the 54% inter-patient variability observed in drug clearance. Course number (CNB) was the only covariate to be correlated with total CDDP clearance. A weaker correlation was found with BSA, and only when considering first courses. Moreover, doses of CDDP administered were significantly higher than the ones classically normalized with BSA, thus leading to an overall greater exposure in our patients. Only few severe toxicities were reported, and all of the patients presented in this study were still alive and disease-free after a follow up of up to 15 years. Conclusions: Our alternative schedule is a convenient and safe strategy to ensure administration of optimal dose-intensity of CDDP, with limited side-effects in patients with testicular cancer. We demonstrate a linear correlation between course number and decrease of CDDP clearance (25%). This, highlights the critical importance of total drug accumulation on CDDP PK when several infusions are to be administered in a row, and therefore the need for developing dynamic dose individualization strategies that includes CNB.

No significant financial relationships to disclose.

Determination of uracil/UH2 ratio as a potential surrogate for DPD status in cancer patients presenting with severe toxicities during fluoropyrimidine treatment

2020

Background: DPD deficiency is a rare pharmacogenetic syndrome leading to overexposure to fluoropyrimidine drugs, with subsequent exacerbation of toxicity and, possibly, fatal outcome in the most severe cases. Methods: We developed a simple and rapid surrogate method for evaluating the DPD status of cancer patients. This method was retrospectively validated by following 860 patients treated with fluoropyrimidines over a 3-year period at our institute. We applied the Uracil to UH2 ratio measurement as an indirect insight into DPD functionality in a subset of 120 patients (14%), who had presented with severe toxicity (grade 3–5, WHO) after fluoropyrimidine administration. We also searched for the canonical IVS14+1G>A single nucelotide permutation (SNP), which is associated with severe DPD deficiency. Results: More than 70% of the patients with severe toxicity and 80% of those with fatal outcome displayed U/UH2 ratios out of the range previously defined with a separate reference, non-toxic population thus strongly suggesting a correlation. In contrast, IVS14+1G>A SNP was not found to be a reliable marker for predicting toxicities. Conclusions: Taken together, our data indicate U/UH2 ratio appears to be frequently implicated in the occurrence of iatrogenic events with fluoropyrimidine therapy. In addition, our simple and rapid HPLC method may meet the requirements of routine screening, allowing identification of patients who might be at risk of severe toxicity during fluoropyrimidine administration, at relatively low cost. The predictive value of our test is being investigated in a prospective study with pharmacokinetic support.

No significant financial relationships to disclose.

Évaluation de l'information donnée aux parents en consultation préanesthésique programmée dans un hôpital pédiatrique

INTRODUCTION

Information given to the parents of paediatric patients during the preanaesthetic consultation (CS) must be understandable.

OBJECTIVE

We have studied the impact of this information given during CS.

METHODS

Prospective study over four months with a questionnaire completed by parents after CS and before the hospitalization. The Sfar information booklet was given to the parents before CS. The study evaluated whether the information had been given ("have you received the information on...?"), understood ("Did you understand...?"), and if CS had influenced anxiety of parents/child; on four items of information, anesthetic risk, transfusion, postoperative pain, and anesthetic technique. The questionnaire noted also the parents sociocultural level (NSC), and if they had read the Sfar booklet. Statistical analysis (descriptive, uni-, multivariate), p<0.05.

RESULTS

Four hundred questionnaires were distributed, 334 were analyzed. The information on the four items was considered to have been given in 75%, understood 72%, and to have diminished anxiety 68%. These results were not influenced by whether or not (88%) parents had read the Sfar booklet. How much information was given was a function of the physician giving the information. Elevated NSC and amount if information given improved comprehension optimized. Diminution of anxiety was when all four items were understood, CS was performed by a senior physician and the parent's NSC was high.

DISCUSSION

Information better adapted to NSC may improve the quality of CS. The Sfar booklet does not contribute to parents understanding in this context.

Impact du grade de Cormack et Lehane sur l'utilisation du masque laryngé Fastrach™ : étude en chirurgie gynécologique

OBJECTIVE

To evaluate the impact of Cormack and Lehane grade on the Intubating Laryngeal Mask Airway (LMA-Fastrach) using in women.

STUDY DESIGN

Open prospective study.

PATIENTS

The study included 115 scheduled gynaecologic surgery women.

METHODS

An LMA-Fastrach was systematically performed in patients with a Cormack's grade > or =3 or when Arne's score was > or =7 whatever the Cormack. After induction of anaesthesia and neuromuscular blockade, Cormack's grade was assessed and LMA-Fastrach was inserted. Proper insertion was confirmed by the easiness of assisted ventilation and the normal aspect of the capnographic curve. Intubation through the LMA-Fastrach was carried out with the specific kit's endotracheal tube. More than two attempts were considered as a failure of the technique and an alternative method was performed. The following parameters were noted: age, weight, height, clinical predictors for difficult intubation (Arne et al.'s score), number of LMA-Fastrach insertion, ventilation efficiency through LMA-Fastrach, successful intubation with LMA-Fastrach and oesophageal intubation.

RESULTS

Ventilation through the LMA-Fastrach was efficient in 97%. The success rate of intubation was 94.8% (86% on the first attempt). The success rate of ventilation and intubation were not statistically different according to the different Cormack's grades. The obesity (BMI>30) did not change the success rate of ventilation and intubation through the LMA-Fastrach.

CONCLUSION

In women with either predicted or unpredicted difficult intubation, the success rates of ventilation and intubation through the LMA-Fastrach don't seem to be influenced by Cormack grade and obesity.

A simple and rapid high-performance liquid chromatographic (HPLC) method for 5-fluorouracil (5-FU) assay in plasma and possible detection of patients with impaired dihydropyrimidine dehydrogenase (DPD) activity

BACKGROUND

Dihydropyrimidine dehydrogenase (DPD) gene polymorphism may lead to severe toxicity with 5-fluorouracil (5-FU), a major anticancer drug extensively used in clinical oncology. Drug monitoring combined with early detection of patients at risk would enable timely dose adaptation so as to maintain drug concentrations within a therapeutic window. However, the best method to identify such patients remains to be determined.

OBJECTIVE

The aim of this study was to develop a rapid and simple high-performance liquid chromatographic (HPLC) method for estimating uracil/dihydrouracil (U/UH2) ratio in plasma, as an index of DPD status, and for assaying 5-FU as part of drug level monitoring.

METHOD

Assay of 5-FU, and U/UH2 detection were performed on a HPLC system equipped with UV detector. Analytes were separated at room temperature using a 5 microm particles, 25 cm RP-18 X-Terra column. The mobile-phase consisted of a KH(2)PO(4) salt solution (0.05 m) + 0.1% triethylamine (TEA) pumped at 0.4 mL/min. Detection of 5-FU and 5-bromouracil were performed at 254 nm; U and UH2 elution was monitored at 210 nm.

RESULTS

The method was sensitive and specific for assaying 5-FU within the 5-500 ng/mL concentration range, which covers exposure levels currently met in clinical practice. The method was simple, and relatively cheap, and rapid, with an analytical run time of about 30 min. Data from a patient with 5-FU toxicity suggest that the method was capable of identifying DPD metabolic phenotype in cancer patients, based on measurement of plasma U/UH2 ratio.

CONCLUSION

The method described should be suitable both for detecting patients at high risk of 5-FU toxicity, and for drug level monitoring during chemotherapy.

Détection de métastases hépatiques du cancer colorectal sous chimiothérapie

OBJECTIVE

To compare MRI of the liver with mangafodipir trisodium (MnDPDP) and computed tomography with intravenous contrast media in the follow-up of liver metastases in patient on chemotherapy for colorectal carcinoma.

MATERIALS AND METHODS

This was a prospective study with patients on chemotherapy for liver metastases from colorectal cancer. Patients underwent both contrast-enhanced helical CT using 2 cc/kg contrast at 3 cc/sec and mangafodipir trisodium-enhanced MR imaging at 1.5 T using 2-3 cc/min contrast at 5 micro mol/kg within a two week interval. Two experienced radiologists independently reviewed all scans in a blinded fashion and recorded image quality as well as presence and number of liver lesions. Statistical analysis was performed using the wilcoxon signed rank test.

RESULTS

All examinations were of good quality. A total of 71 lesions were detected at CT, with 69 lesions consistent with metastases and 2 lesions consistent with cysts. A total of 98 lesions were detected at MRI, with 97 consistent with metastases and 1 lesion consistent with a cyst. T1 weighted images with MnDPDP significantly detected two additional lesions compared to CT (p<0.05). No significant difference was demonstrated between T1 weighted images without MnDPDP and CT or between T2 weighted images and CT.

CONCLUSION

Magnetic resonance imaging with MnDPDP is significantly more sensitive than unenhanced MRI and helical CT for the follow-up of liver lesions.

Puromycin selectively increases mdr1a expression in immortalized rat brain endothelial cell lines

The blood-brain barrier (BBB) plays an important role in controlling the passage of molecules from blood to brain extracellular fluid. The multidrug efflux pump P-glycoprotein (P-gp) is highly expressed in the luminal membrane of brain endothelium and contributes to the formation of a functional barrier to lipid-soluble drugs such as anticancer agents. The mdr1a P-gp-encoding gene is exclusively expressed in the rodent BBB. Primary cultures of rat brain endothelial cells and GP8.3 cells showed a dramatic decrease in mdr1a mRNA level and some expression of mdr1b mRNA. GPNT cells, derived from GP8.3 cells after transfection with a puromycin resistance gene, were chronically treated with 5 microg/mL puromycin, a P-gp substrate. Compared with rat brain endothelial cells and GP8.3 cells, GPNT cells exhibited a very high level of expression of mdr1a mRNA together with a moderate level of mdr1b mRNA expression. Accordingly, P-gp expression and activity were strongly increased. When GP8.3 and puromycin-starved GPNT cells were treated with puromycin, mdr1a expression was selectively increased. High expression of mdr1a mRNA in GPNT cells may thus be related to the chronic treatment with puromycin. We conclude that GPNT cells may be used as a valuable rat in vitro model for studying the regulation of mdr1a expression at the BBB level.

Standard preoxygenation technique versus two rapid techniques in pregnant patients

The aim of this study was to compare three different preoxygenation techniques in pregnant women by measuring end-tidal fractional oxygen concentration (FETO2): the traditional technique of 3min tidal volume breathing (VT x 3 min), 8 deep breaths (8 DB) and 4 deep breaths (4 DB). Twenty pregnant volunteers without pulmonary diseases were studied during the third trimester (36-38 weeks' gestation). Women were preoxygentated using a non-rebreathing respiratory circuit with a 3-L reservoir bag and a Capnomac Ultima calibrated before each patient to monitor FETO2 continuously. The three preoxygenation techniques were investigated in random order: VT x 3 min using an oxygen flow of 9 L min-1, 4 DB within 30s using an oxygen flow of 9 L min-1, and 8 DB within one minute using an oxygen flow of 15 L min-1. Between each technique, 5-min room air breathing was allowed to return to baseline FETO2 assessed by the Capnomac Ultima. An FETO2 >/= 90% was achieved more frequently with the VT x 3 min and the 8 DB techniques (76%) than with the 4 DB technique (18%) (P < 0.05). The average time required for obtaining an FETO2 >/= 90% was 107+/-37s. Both the VT x 3 min and the 8 DB techniques are therefore more effective for preoxygenation in pregnant patients than the 4 DB technique. In an acute obstetric emergency before rapid-sequence induction of general anaesthesia, 8 DB preoxygenation technique could be recommended.

Recurrences following primary osteosarcoma in adolescents and adults previously treated with chemotherapy

In this retrospective analysis, we report on the detailed management of 33 recurrent osteosarcoma patients from a population of 81 adolescents and adults previously treated (between November 1979 and November 1998) at the La Timone Adults Hospital, for an extremity-localised osteosarcoma. The site of the first recurrence was limited to the lung in 24 patients (73%), was local in 4 patients (12%), at multiple sites in 4 patients (12%), and limited to the bone for 1 patient (3%). The median interval between the diagnosis of the primary osteosarcoma and the first recurrence was 16 months (range 4-108 months). For all patients, the treatment combined aggressive chemotherapy and surgical resection of the recurrences whenever possible. 19 patients (58%) achieved a second complete remission. The median follow-up time from the first recurrence was 18 months (range 4-150 months). For all patients, the median overall survival from first recurrence was 17 months (95% confidence interval (CI), 11-22 months) and the projected 3- and 5-year survival rates were 31.6 and 23.7%, respectively. Patients with a second complete remission had a better 5-year survival than patients without (44.6% versus 0%, P=0.001). The achievement of a second complete remission has an independent significant prognostic value for an improved survival. Aggressive surgery with the removal of recurrence sites combined with multi-agent chemotherapy can either cure patients with recurrent osteosarcoma or significantly prolong their survival.

The pathological basis of temporal lobe epilepsy in childhood

OBJECTIVE

To characterize the pathologic findings of temporal lobe epilepsy (TLE) in children undergoing temporal lobectomy for refractory seizures and to correlate these findings with clinical presentation.

METHODS

The authors reviewed the charts of all children who underwent anterior temporal lobectomy for refractory TLE from 1979 through 1999. A new neuropathologic analysis was performed blinded to clinical features and outcome.

RESULTS

Twenty-two children met inclusion criteria. Mean age at onset of epilepsy was 3 years, 7 months (range 1 month to 10 years). Mean age at surgery was 10 years, 11 months (range 1 to 18 years). All patients had complex partial seizures, 48% with secondary generalization. Most had daily seizures. Auras were reported in 45% of patients. Post-resection follow-up averaged 5 years, 2 months (range 2 to 19 years). Seizure-free status was achieved in 41% of patients, and 14% had residual auras only. The most frequent neuropathologic abnormalities were cortical dysplasia (CD) of the temporal neocortex (14 of 22) and mesial temporal sclerosis (MTS) (12 of the 15 children with available hippocampal tissue). These two findings coexisted in seven children. MTS was associated with extra-hippocampal pathology in 8 of 12 (67%) of the cases.

CONCLUSIONS

MTS occurs frequently in association with CD in this population of children. The high incidence of dual pathology could explain the early age of seizure onset and high seizure frequency rate observed. TLE in childhood may constitute a different entity than in adults, from both the clinical and neuropathologic perspectives.

[Postoperative comfort in pediatric outpatient tonsillectomy]

OBJECTIVE

Evaluate the comfort in children after ambulatory tonsillectomy, disregarding the surgical technique and with a systematic prescription of paracetamol and codeine. The study lasted 4 days including the day of surgery.

STUDY DESIGN

[corrected] Prospective study during 5 months.

PATIENTS AND METHODS

We performed a prospective study over a five-month period to evaluate the comfort in children after ambulatory tonsillectomy. Opioids were used for analgesia during surgery, morphine and propacetamol in the recovery room, and a systematic prescription of paracetamol-codeine between Day 0 to Day 3 at home. The assessment of pain was made by nurses and the family, considering 6 endpoints: spontaneous pain and when swallowing by verbal scale (0 to 4), occurrence of PONV (0 or 1), quality of sleep (0 or 1), quality of feeding (0 or 1) and play (0 or 1), combined in a global score of 0 to 12, with a score < or = 4 very satisfactory.

RESULTS

78 children were included, 49 tonsillectomy by dissection, 29 by Sluder. The score were < or = 4 at Day 0 and Day 1 in 53 children, but statistical analysis (univariate analysis) showed difference between the two surgical procedures with a global comfort score better and PONV lower with dissection procedure.

CONCLUSION

The use of paracetamol-codeine after tonsillectomy offers a reliable analgesia with very satisfactory scores of comfort. Such prescription is effective in ambulatory tonsillectomy if a rigorous selection of patients is made.

Incidence of postoperative nausea and vomiting in paediatric ambulatory surgery

BACKGROUND

We performed a prospective descriptive study over a 5-month period to determine the incidence of postoperative nausea and vomiting (PONV) during the first 24 h following elective ambulatory paediatric surgery, excluding head and neck procedures.

METHODS

Four hundred and seven patients, aged 15 days to 16 years, were analysed prospectively.

RESULTS

The incidence of PONV was 9.4%, occurring most frequently during the first 3 h after anaesthesia and in hospital but rarely during the journey home. It was associated with age, previous history of PONV, tracheal intubation or use of the laryngeal mask airway (LMA trade mark ), controlled or manual ventilation, opioids and absence of oral intake of liquids or solids. Conversely, type of surgery, premedication, induction mode, association of regional anaesthesia, inhaled nitrous oxide, duration of anaesthesia, stay in the postanaesthesia care unit and duration of journey after discharge were not significantly associated with PONV.

CONCLUSIONS

PONV never induced complications or delayed patient discharge and curative treatment was rapidly effective.

[Emergency unilateral mydriasis]

UNEQUAL PUPILS: Or anisocoria is frequent and can be physiological, benign or life threatening. VARIATIONS IN THE PUPIL: Constriction depends on the parasympathetic system and dilatation on the sympathetic system. IN PARASYMPATHETIC DISORDERS: Peripheral or central neurological causes can be distinguished, among which acute cerebral lesions with compression of the trunk are the most dramatic. Differential diagnosis can be made by studying the local causes, which may represent ophthalmologic emergencies (acute glaucoma or lesions of the retina). AMONG THE SYMPATHETIC DISORDERS: Claude-Bernard-Horner's syndrome is the most classical example. Other particular cases exist, such as Adie's pupil, affecting young women (1/20,000), associating mydriasis and occasionally tendinous areflexia. Diagnosis is generally confirmed by the ophthalmologist, following a normal or evocative of the disease neurological examination.

IN PRACTICE

Rapid but careful clinical examination permits orientation of the diagnosis and appropriate treatment.

Demographic analysis of tree colonization in a 20-year-old right-of-way

Past tree colonization dynamics of a powerline-right-of-way (ROW) corridor in the Haut-Saint-Laurent region of Quebec was studied based on the present age distribution of its tree populations. This colonization study spans 20 years, from 1977 (ROW clearance) to 1996. The sampled quadrats were classified into six vegetation types. Tree colonization dynamics were interpreted in each type, and three distinct patterns were identified. (1) Communities adapted to acidic conditions were heavily colonized by Acer rubrum, at least for the last 12 years. (2) Communities adapted to mesic or to hydric conditions were more intensely colonized in the period 1985-1987 than in the following 9 years; this past success in tree colonization may have been caused by herbicide treatments, which could have facilitated tree establishment by damaging the herbaceous and shrub vegetation. (3) Cattail, vine-raspberry, and reed-dominated communities contained few tree individuals, with almost all trees establishing between 1979 and 1990; those three vegetation types appear as the most resistant to tree invasion in the ROW studied. This study supports the need for an integrated approach in ROW vegetation management, in which the selection of vegetation treatment methods would depend on the tree colonization dynamics in each vegetation type. Minimizing disturbances inflicted on ROW herbaceous and shrub covers should be the central strategy because disturbances jeopardize natural resistance to future tree invasion, except in communities adapted to acidic conditions where the existing vegetation does not prevent invasion by A. rubrum. Many trees are surviving the successive cutting operations by producing new sprouts each time, particularly in communities adapted to mesic and hydric conditions. In these cases, mechanical cutting should be replaced by a one-time stump-killing operation, to avoid repeated and unsuccessful treatments of the same individuals over time.

Tumorigenicity of the mixed spindle-epithelioid SP6.5 and epithelioid TP17 uveal melanoma cell lines is differentially related to alpha5beta1 integrin expression

PURPOSE

It has been suggested that the epithelioid morphology and high aggressiveness that is typical of the uveal melanoma cell line TP17 is dependent on the loss of alpha5beta1 integrin expression at the cell surface. The purpose of the current study was to test this hypothesis in the TP17 cell line and investigate the role this integrin may play in the tumorigenicity of the SP6.5 cells, a mixed spindle-epithelioid culture-type human uveal melanoma that shows tumorigenic properties clearly distinct from that of TP17 cells.

METHODS

Expression of the alpha5 integrin subunit was restored in the alpha5-TP17 cell line by stably transfecting the cells with a recombinant plasmid encoding the integrin subunit. Flow cytometry and adhesion assays on fibronectin (FN)-coated culture plates were used to monitor alpha5 expression in the cells. The effect of alpha5 expression on both tumorigenicity and cell proliferation was evaluated in vivo in nude mice. In vitro growth properties of the alpha5(+) TP17 cells was evaluated by cell counting and compared with that of the alpha5 parental TP17 cell line. The influence exerted by the alpha5 integrin subunit on the tumorigenic and proliferative properties of the SP6.5 cells was evaluated in vivo in nude mice by exposing the cells to increasing doses of a blocking antibody directed against the alpha5-subunit before subcutaneous injection, and compared with the results obtained with untreated SP6.5 cells.

RESULTS

Expression of the alpha5 integrin subunit in the alpha5-TP17 cells was successfully achieved, as evidenced by both flow cytometry and adhesion assays on FN-coated culture plates. Restoring expression of alpha5 in TP17 cells enhanced epithelioid cell morphology and increased the growth properties of this cell line in vivo. The ability of the SP6.5 cells to yield subcutaneous tumors was found to be concentration dependent and was reduced in a dose-dependent manner when the cells were exposed to the anti-alpha5 blocking antibody.

CONCLUSIONS

Restoring expression of alpha5 in the alpha5-negative TP17 uveal melanoma cell line influenced the proliferative properties of these cells but did not alter its tumorigenic potential. In contrast, the ability of the SP6.5 cells to yield tumors in vivo in nude mice appeared to be related to expression of this integrin.