Assessment of operator performance during oocyte retrievals: residents' learning curve and continuous monitoring of senior physicians

BACKGROUND

The learning curve cumulative summation test (LC CUSUM test) allows to define an individualized learning curve and determine the moment when clinical proficiency is attained. After acquisition of the skills, the cumulative summation test (CUSUM test) allows to monitor the maintenance of the required level over time. The LC CUSUM test has been frequently used in the field of Obstetrics and Gynecology (Ob/Gyn) for several procedures, but only once for OR.

METHODS

We performed a retrospective study at Angers university hospital between May 2017 and September 2018. Seven Ob/Gyn residents and 5 senior physicians were included, and all OR performed during that time (n = 690) were analyzed. The performance index assessed was the oocyte retrieval rate (ORR), defined as the ratio of oocytes retrieved to follicles aspirated. We used the LC CUSUM test to analyze the learning curves of residents, and the CUSUM test to monitor the performance of senior physicians. An ORR ≥50% in 60% of retrievals was defined as the threshold for clinical proficiency.

RESULTS

Six hundred seventy-four oocyte retrieval (OR) were included: 315 were performed by residents, 220 by senior physicians, and 139 by both residents and physicians (mixed retrievals). Four residents (57%) reached the threshold after aspirating 82, 67, 53 and 46 ovaries, respectively. The mean number of ovaries aspirated in order to reach clinical proficiency was 62, and the mean number of weeks needed was 21. The duration of the learning period varied between 26 and 80 days. Two senior physicians (40%) remained proficient across the duration of the study, while two physicians (40%) had one statistically "suboptimal" OR, and one physician (20%) had two suboptimal retrievals.

CONCLUSION

There is a large variability in the duration of the learning period and the number of procedures needed for a resident to master OR. Senior physicians maintain an adequate performance.

FRI0154 SHOULD BE OLDER PATIENTS TESTED FOR ANTIPHOSPHOLIPID ANTIBODIES? 695 CASES FROM THE RETROSPECTIVE SERIES HIBISCUS

Background:

Although guidelines do not recommend antiphospholipid antibodies testing after 60 yo, recent data reported late onset antiphospholipid syndrome (APS).

Objectives:

To comparatively analyse the clinical, laboratory features and outcomes in 695 cases with primary APS between patients older and younger than 70 yo.

Methods:

we have performed an international study within the framework of the International Registry of primary APS patients treated with Hydroxychloroquine, HIBISCUS (an ongoing retrospective and prospective register launched in 2016). 28 centres from 17 countries participate. Data about late onset APS were analysed in 695 patients and were obtained from a standardized form registered in the database containing 66 items with respect to demographics, clinical and biological features.

Results:

Arterial events and especially stroke represented the main initial and recurrent clinical manifestation in 40 primary APS patients older than 70 yo. There were not statistically significant differences with respect to cardiovascular risk factors between the two groups of patients. A significant male predominance, a familial APS history, a higher prevalence of triple positivity, lower complement levels, and anticardiolipin antibodies (aCL) IgA isotype were found in older patients. Low anticoagulation regimens were safe and efficient, with a low relapse rate in older patients.

Conclusion:

we suggest that the detection of aPL antibodies should be included into the initial screening panel tests in elderly with thrombotic events, especially arterial, in particular those with recurrent stroke and familial APS.

Our study further suggests that lower intensity anticoagulation regimens could be a therapeutic option in older APS patients, as no differences in outcomes and relapse rate were found between patients with high and low intensity anticoagulation regimens.

References:

[1]Grimaud F et al. Rheumatology. 2019;58:1006-10.

[2]Goldman-Mazur S et al. Thromb Res. 2019;176:67-73.

[3]Hirmerova J et al. 2017;36:167-73.

Disclosure of Interests:

Cristina Belizna: None declared, Omar Latino: None declared, Ljudmila Stojanovich: None declared, Patrick Saulnier: None declared, Katrien Devreese: None declared, Sebastien Udry: None declared, Natasa Stanisavljevic: None declared, Aleksandra Djokovic Speakers bureau: KRKA, Astra Zeneca, Actavis, Jaume Alijotas-Reig: None declared, Enrique Esteve-Valverde: None declared, Raquel Ferrer-Oliveras: None declared, Angela Tincani: None declared, Laura Andreoli: None declared, Francesca Regola: None declared, Maarten Limper: None declared, Alexander Makatsariya: None declared, Jamilya Khizroeva: None declared, Viktoria Bitsadze: None declared, Cecilia Chighizola: None declared, Francesca Pregnolato: None declared, Maria Orietta Borghi: None declared, Pier Luigi Meroni: None declared

[Can positron emission tomography assessment of response to treatment help to individualize use of erlotinib in non-small cell lung cancer?]

Erlotinib can be prescribed in the treatment of locally advanced or metastatic non-small lung cancer cell (NSCLC) after failure of at least one prior chemotherapy regimen on the basis of the BR-21 study. Several publications have recently questioned these results. The metabolic imaging of solid tumours by positron emission tomography is a research field that could help customize the treatment of NSCLC and so complement the treatment approaches allowed by genetic analyses. This strategy is part of an innovative "early metabolic look" approach. The primary objective of this study is to determine if metabolic progression observed between the 7th and 14th day after initiation of treatment with erlotinib by 3'-Deoxy-3'-[18F]-Fluorothymidine PET in patients with EGFR naive NSCLC is predictive for morphological progression after 6 to 8 weeks of treatment. A health economic analysis will be conducted. This study is particularly innovative because it begins the exploration of the era of metabolic evaluation of therapeutic response in NSCLC.

Perfluorocarbon-loaded lipid nanocapsules as oxygen sensors for tumor tissue pO₂ assessment

The assessment of tumor oxygenation is a crucial factor in cancer therapy and may be carried out using fluorine MRI once fluorine probes have been distributed within the tumor. However, the deposit of those highly fluorinated compounds often jeopardizes anatomical image quality and requires emulsification of the probes. Due to the high density and the high lipophilicity of perfluorocarbons, nanoemulsion of these molecules usually requires high-energy processes. In the present work, we discuss the synthesis and the physico-chemical characterization of perfluorocarbon nanocapsules using a low-energy phase-inversion process. The nanocapsules were tested on a mouse tumor brain model to assess oxygenation.

High frequency of beta-catenin heterozygous mutations in extra-abdominal fibromatosis: a potential molecular tool for disease management

Background:

Fibromatosis comprises distinct clinical entities, including sporadic extra-abdominal fibromatosis, which have a high tendency for recurrence, even after adequate resection. There are no known molecular biomarkers of local recurrence. We searched for β-catenin mutations in a European multicentre series of fibromatosis tumours to relate β-catenin mutational status to disease outcome.

Methods:

Direct sequencing of exon 3 β-catenin gene was performed for 155 frozen fibromatosis tissues from all topographies. Correlation of outcome with mutation rate and type was performed on the extra-abdominal fibromatosis group (101 patients).

Results:

Mutations of β-catenin were detected in 83% of all cases. Among 101 extra-abdominal fibromatosis, similar mutation rates (87%) were observed, namely T41A (39.5%), S45P (9%), S45F (36.5%), and deletion (2%). None of the clinico-pathological parameters were found to be significantly associated with β-catenin mutational status. With a median follow-up of 62 months, 51 patients relapsed. Five-year recurrence-free survival was significantly worse in β-catenin-mutated tumours regardless of a specific genotype, compared with wild-type tumours (49 vs 75%, respectively, P=0.02).

Conclusion:

A high frequency (87%) of β-catenin mutation hallmarks extra-abdominal fibromatosis from a large multicentric retrospective study. Moreover, wild-type β-catenin seems to be an interesting prognostic marker that might be useful in the therapeutic management of extra-abdominal fibromatosis.

Lipid nanocapsules: a new platform for nanomedicine

Nanomedicine, an emerging new field created by the fusion of nanotechnology and medicine, is one of the most promising pathways for the development of effective targeted therapies with oncology being the earlier and the most notable beneficiary to date. Indeed, drug-loaded nanoparticles provide an ideal solution to overcome the low selectivity of the anticancer drugs towards the cancer cells in regards to normal cells and the induced severe side-effects, thanks to their passive and/or active targeting to cancer tissues. Liposome-based systems encapsulating drugs are already used in some cancer therapies (e.g. Myocet, Daunoxome, Doxil). But liposomes have some important drawbacks: they have a low capacity to encapsulate lipophilic drugs (even though it exists), they are manufactured through processes involving organic solvents, and they are leaky, unstable in biological fluids and more generally in aqueous solutions for being commercialized as such. We have developed new nano-cargos, the lipid nanocapsules, with sizes below the endothelium fenestration (phi<100 nm), that solve these disadvantages. They are prepared according to a solvent-free process and they are stable for at least one year in suspension ready for injection, which should reduce considerably the cost and convenience for treatment. Moreover, these new nano-cargos have the ability to encapsulate efficiently lipophilic drugs, offering a pharmaceutical solution for their intravenous administration. The lipid nanocapsules (LNCs) have been prepared according to an original method based on a phase-inversion temperature process recently developed and patented. Their structure is a hybrid between polymeric nanocapsules and liposomes because of their oily core which is surrounded by a tensioactive rigid membrane. They have a lipoprotein-like structure. Their size can be adjusted below 100 nm with a narrow distribution. Importantly, these properties confer great stability to the structure (physical stability>18 months). Blank or drug-loaded LNCs can be prepared, with or without PEG (polyethyleneglycol)ylation that is a key parameter that affects the vascular residence time of the nano-cargos. Other hydrophilic tails can also be grafted. Different anticancer drugs (paclitaxel, docetaxel, etoposide, hydroxytamoxifen, doxorubicin, etc.) have been encapsulated. They all are released according to a sustained pattern. Preclinical studies on cell cultures and animal models of tumors have been performed, showing promising results.

Quantitative methylation analyses of resection margins predict local recurrences and disease-specific deaths in patients with head and neck squamous cell carcinomas

This study sought to determine whether the presence of hypermethylated genes in the surgical margins can predict local recurrences in head and neck squamous cell carcinomas (HNSCCs). We prospectively collected tumour and surgical margin specimens from patients with HNSCCs who had undergone surgical resections. Quantitative methylation-specific PCR (QMSP) of CDKN2A, CCNA1 and DCC were performed in these specimens and correlated with clinical data. Of the 42 patients eligible for the study, 27 were hypermethylation informative for the above three genes. This latter group was associated with longer disease-free survivals (P=0.007) and longer time to disease-specific deaths (P=0.004). Multivariate analyses confirmed hypermethylation non-informative tumours as an independent prognosticating factor for disease-specific deaths (risk ratio 3.8, P=0.026). Quantitative MSP of the margins of 24 hypermethylation informative tumours revealed that 11 patients had molecularly positive margins, of which, five developed disease-specific events (DSEs, three local recurrences and two metastases), compared to none in patients with molecularly negative margins, after a median follow-up of 48 months. Log-rank analyses showed that molecularly positive margins were associated with shorter time to local recurrences and disease-specific deaths (P=0.03 and 0.01, respectively). This study demonstrated that QMSP of hypermethylated promoters in surgical margins predicted all the local recurrences in our series of HNSCC patients. We have also identified hypermethylation non-informative tumours as an independent predictor for the development of DSEs.

Formulation of sustained release nanoparticles loaded with a tripentone, a new anticancer agent

The purpose of the present work is to develop nanoparticles of a new antitubulin agent of the family of tripentones by means of a phase inversion process. Dynamic light scattering, transmission electron microscopy and zeta-potential measurements were used to characterize tripentone loaded nanoparticles. From interfacial tension measurements and from the study of the rheological interfacial properties of the tripentone at the Labrafac-Solutol interface, the fraction of tripentone initially present in Labrafac would stay in the oily core of nanocapsules. Moreover, the interpenetration of some tripentone molecules within the surfactant units helps to the stabilization of the formulated nanoparticles. The encapsulation efficiency was determined by high performance liquid chromatography (HPLC) and was found to be above 95%. In vitro release studies were carried out in blank nanoparticles containing phosphate buffer, pH 7.4, at 37 degrees C. The drug release kinetics was measured by HPLC. Antiproliferative activity studies on L1210 cells showed that the cytotoxic activity of tripentone was totally recovered after encapsulation of the antitubulin agent in lipid nanoparticles. This study shows that lipid nanocapsules could be a promising and effective carrier for tripentone delivery in the treatment of cancers.

Evaluation of pegylated lipid nanocapsules versus complement system activation and macrophage uptake

This work consisted in defining the in vitro behavior of pegylated lipid nanocapsules (LNC) toward the immune system. LNC were composed of an oily core surrounded by a shell of lecithin and polyethylene glycol (PEG) known to decrease the recognition of nanoparticles by the immune system. The "stealth" properties were evaluated by measuring complement activation (CH50 technique and crossed-immunoelectrophoresis (C3 cleavage)) and macrophage uptake. These experiments were performed on 20-, 50-, and 100-nm LNC before and after dialysis. A high density of PEG at the surface led to very low complement activation by LNC with a slight effect of size. This size effect, associated to a dialysis effect in macrophage uptake, was due to differences in density and flexibility of PEG chains related to LNC curvature radius. Thanks to a high density, 660-Da PEG provided LNC a steric stabilization and a protective effect versus complement protein opsonization, but this protection decreased with the increase of LNC size, especially versus macrophage uptake.

Reorganization of lipid nanocapsules at air–water interface

The size, the electrical properties and the behaviour at air-water interface of lipid nanocapsules (LNC) with various compositions were investigated. Two populations of LNC are presented in the suspension after the preparation: with (LNC II) and without (LNC I) phospholipid molecules. After the spreading at air-water interface, a rapid disaggregation of LNC I, located in the vicinity of interface, occurs leading to formation of surface film. The phospholipid molecules stabilize the structure of nanocapsules and LNC II are more stable at the interface in comparison with LNC I. The formation of a surface film was followed after by measuring the evolution of the surface pressure, relative surface area change and surface potential. A kinetic approach describing the various processes during the surface film formation was proposed. The corresponding kinetic constants were estimated.

Reorganization of lipid nanocapsules at air–water interface

The state, electrical and dilatational rheological properties of surface films formed at air-water interface from lipid nanocapsules (LNC) with various compositions as well as model monolayers formed by the LNC constituents-Labrafac, Solutol and Lipoid are investigated. These nanocapsules constitute potential drug delivery systems where lypophilic drug will be loaded in their core. The study of the model Labrafac/Solutol (Lab/Sol) mixed monolayers shows behavior close to the ideal. Small negative deviations in the mean molecular areas a and dipole moments mu are observed. All studied monolayers have elastic behavior during the small continuous compressions. The comparison between the properties of surface films formed from LNC with those of the model monolayers confirms the idea developed in the kinetic study that the surface films formed after a rapid disaggregation of the unstable nanocapsule fraction (LNC I) contains mainly Labrafac and Solutol. The Labrafac molar part (xLab) in the formed Lab/Sol mixed layer is established.

Pharmacologically active microcarriers: a tool for cell therapy

To overcome certain problems encountered in cell therapy, particularly cell survival, lack of cell differentiation and integration in the host tissue, we developed pharmacologically active microcarriers (PAM). These biodegradable particles made with poly(D,L-lactic-co-glycolic acid) (PLGA) and coated with adhesion molecules may serve as a support for cell culture and may be used as cell carriers presenting a controlled delivery of active protein. They can thus support the survival and differentiation of the transported cells as well as their microenvironment. To develop this tool, nerve growth factor (NGF)-releasing PAM, conveying PC12 cells, were produced and characterized. Indeed, these cells have the ability to differentiate into sympathetic-like neurons after adhering to a substrate, in the presence of NGF, and can then release large amounts of dopamine. Certain parameters such as the size of the microcarriers, the conditions enabling the coating of the microparticles and the subsequent adhesion of cells were thus studied to produce optimized PAM.

Bcl-2 and CCND1/CDK4 expression levels predict the cellular effects of mTOR inhibitors in human ovarian carcinoma

Molecular markers enabling the prediction of sensitivity/resistance to rapamycin may facilitate further clinical development of rapamycin and its derivatives as anticancer agents. In this study, several human ovarian cancer cell lines (IGROV1, OVCAR-3, A2780, SK-OV-3) were evaluated for susceptibility to rapamycin-mediated growth inhibition. The differential expression profiles of genes coding for proteins known to be involved in the mTOR signaling pathway, cell cycle control and apoptosis were studied before and after drug exposure by RT-PCR. In cells exposed to rapamycin, we observed a dose-dependent downregulation of CCND1 (cyclin D1) and CDK4 gene expression and late G1 cell cycle arrest. Among these cell lines, SK-OV-3 cells resistant to both rapamycin and RAD001 were the sole to show the expression of the anti-apoptotic gene Bcl-2. Bcl-2/bclxL-specific antisense oligonucleotides restored the sensitivity of SK-OV-3 cells to apoptosis induction by rapamycin and RAD001. These results indicate that baseline Bcl-2 expression and therapy-induced downexpression of CCND1 and CDK4 may be regarded as molecular markers enabling the prediction and follow-up of the cellular effects on cell cycle and apoptosis induction of rapamycin in ovarian cancer. Furthermore, strategies to down regulate Bcl-2 in ovarian cancer may prove useful in combination with rapamycin or RAD001 for ovarian cancer.

Plant protein-polysaccharide interactions in solutions: application of soft particle analysis and light scattering measurements

The soft particle analysis theory was applied to plant proteins and polysaccharides in solution, to determine the charge density of these polymers and the depth of the layer accessible by counterions according to pH conditions. In addition to the macromolecule shape characterized by light scattering measurements, these properties are also correlated with the optimum coacervation condition, so as to establish the prevalent plant protein-polysaccharide interactions governing the coacervate formation. Globulin was found to be highly charged and spherically shaped. The best coacervation condition was obtained at the pH value, which corresponds to the protein conformation with a dense and compact accessible layer. On the contrary, for the alpha gliadin, bearing a lower charge, a more extended conformation seems to be more favourable. For the plant proteins studied, the coacervation seems to be controlled by the structure of the counter polyanion used: from our model, it turns out that the rod-like structure of arabic gum observed at acidic pH allows the interaction with plant proteins to form coacervates, contrary to the highly charged and spherical structure of alginate.

Interfacial properties of adsorbed films made of a PEG2000 and PLA50 mixture or a copolymer at the dichloromethane–water interface

Adsorption kinetics of films of poly(ethylene glycol) (PEG2000) studied by the dynamic pendant drop method showed that PEG2000 was more tensioactive at the dichloromethane (DCM)-water interface than at the air-water interface. When initially solubilized into DCM, PEG2000 segments would form an adsorbed layer with hydrophobic segments buried into the polymer chains turned toward the organic phase. Compression of this layer, accompanied by viscoelastic effects, led to expulsion of some hydrophilic tails toward the water phase. When initially dissolved in water, adsorption of PEG2000 segments led to an elastic PEG2000 layer organized on both sides of the interface. Results showed that when the PEG2000-PLA50 (poly(D,L-lactide)) copolymer film was adsorbed at the DCM-water interface, it resulted in a mixed layer exclusively turned toward DCM and its rheological properties were governed by PLA50. When adsorption at the DCM-water interface resulted from a physical mixture of PEG2000 and PLA50, rheological properties of the film were influenced by the initial localization of PEG2000 in the bulk phases. In the case of a mixed film formed by the adsorption of PLA50 from DCM and PEG2000 from water, results showed that PEG2000 segments totally pushed those of PLA50 away from the interface and exclusively influenced the behavior of the mixed film.

Recombinant adenovirus shedding after intratumoral gene transfer in lung cancer patients

We conducted two phase 1 trials of direct intratumoral injection of a recombinant E1E3-deleted adenovirus (AdR) encoding either the bacterial enzyme beta-galactosidase (Ad.RSVbetagal) or interleukin 2 (IL2, AdTG5327) into primary nonsmall-cell lung cancers of 21 patients. We report here virus shedding and the duration of virus expression in the tumor after intrabronchial injection of 10(7), 10(8) or 10(9) PFU of adenovirus. The infectious AdR and the viral DNA were detected in PBL, plasma, stool and aerodigestive samples in a dose-dependent manner, since cell cultures and PCRs were found to be positive mainly for samples from patients who received the highest AdR dose (10(9) PFU). We detected beta-galactosidase activity in the tumor biopsy samples of 66% of the patients, seemingly dose related, and only low levels of IL2 mRNA could be detected in tumor biopsy samples. E1 sequences were not detected by PCR in any of the PBL and bronchial samples collected after virus delivery, except in one patient. In this patient, E1 sequences were detected in PBL as well as in tumor biopsy samples collected at days 8, 30 and 60 and were correlated with longer beta-galactosidase expression in tumor samples. PBL tested before and after virus delivery contained both E1 sequences indicating that they did not result from replication-competent adenovirus (RCA) E1 sequences present in the inoculum. In addition, only on the day of the injection was Ad.RSVbetagal also detected in E1-positive PBL, indicating that virus replication in blood was very unlikely.

Genetic manipulations of adenovirus type 5 fiber resulting in liver tropism attenuation

The development of genetically modified adenoviral vectors capable of specifically transducing a given cell population requires the addition and functional presentation of particular tropism determinants within the virus capsid, together with the abrogation of the molecular determinants that dictate their natural tropism in vivo. The human adenovirus serotype 5 (Ad5) first attaches to the cell surface following high-affinity binding of the C-terminal knob of the fiber capsid protein to the coxsackie and adenovirus receptor (CAR). Here we have assessed whether genetic shortening of the fiber shaft (virus BS1), or replacing the Ad5 fiber shaft and knob with their Ad3 counterparts (virus DB6), could cripple this interaction in vitro and in vivo. A 10-fold decrease in the binding of the modified capsids to soluble CAR was evidenced, which correlated with a similar reduction of their ability to transduce CAR-positive cells in vitro. The ability of BS1 to interact with cellular integrins was also impaired, suggesting that the penton base and the short-shafted fiber when embedded in the capsid preclude each other from efficiently interacting with their cognate cell surface receptors (CAR and integrins respectively). BS1 and DB6 intravenous injections in mice further supported a profound impairment of the ability of the capsid-modified viruses to transduce the liver as demonstrated by a 10-fold reduction of intracellular viral DNA and transgene expression. Interestingly enough, the host humoral response was also specifically weakened in BS1- and DB6-inoculated animals. Taken together, these observations indicate that (i) fiber shortening and (ii) pseudo-typing of Ad5-based vectors with the shaft and knob from non-CAR-binding serotypes constitute two promising strategies to successfully attenuate their native tropism in vitro and most importantly in vivo.

Properties of polyethylene glycol 660 12-hydroxy stearate at a triglyceride/water interface

This study proposed a method to understand the surfactant role in the first step of the formulation of a novel generation of lipidic nanocapsules. A dynamic rheological protocol was applied using a pendant drop tensiometer in order to determine the interfacial properties of the initial mixture implied in the first formulation step. The response, in terms of interfacial elasticities, described how this mixture led to monodisperse nanometer size range structures after a physico-chemical constraint.

Development and characterization of solid lipid nanoparticles loaded with magnetite

This paper describes the preparation of colloidal lipid particles containing magnetite from warm emulsions. A two step method was used to obtain the nanoparticles: (i) formulation of a transparent phase by heating a O/W emulsion (aqueous surfactant solution melted with a lipid phase, containing the ethyl oleate and soybean lecithin) in which modified lipophilic magnetite is incorporated, and (ii) preparation of the nanoparticles by dispersing the warm transparent phase in cold water (7 degrees C) under mechanical stirring. The latter method gives spherical nanoparticles of a mean size of 62 nm measured by Photon Correlation Spectroscopy and Transmission Electronic Microscopy. The magnetite entrapment efficiency was determined by use of a magnetophoretic sedimentation method.

Prevalence of virulence genes and clonality in Escherichia coli strains that cause bacteremia in cancer patients

Phenotypic analysis of Escherichia coli strains causing bacteremia in cancer patients suggests that they possess specific virulence properties. To investigate this hypothesis, we compared the frequency of the virulence-related genes cnf1, cnf2, papC, hlyC, and iut in 155 E. coli strains isolated from hospitalized cancer patients with epidemiologically unrelated cases of bacteremia to their frequency in 70 E. coli strains isolated from the feces of healthy unrelated volunteers. Of the blood isolates, 24, 37, and 26% were positive for cnf1, papC, and hlyC, respectively, versus only 6, 17, and 6% of the fecal isolates (P < 0.05 in all instances). By contrast, 47% of both isolates carried the iut gene. The patients' clinical characteristics did not significantly influence these frequencies. The presence on various pathogenicity islands (PAIs) of a combination of the cnf1, papC, and hlyC genes on the chromosome was strongly suggested by Southern blotting of pulsed-field gel electrophoresis (PFGE) patterns with specific DNA probes. The phylogenetic relatedness among 60 strains carrying three, two, one, or no virulence genes and 6 ECOR strains included as references was determined by neighbor joining, the unweighted pair-group method with arithmetic mean, and Wagner analysis of the randomly amplified polymorphic DNA (RAPD) patterns generated by 11 primers. Identification of a major cluster including 96.4% of the strains carrying the cnf1, papC, and hlyC genes and ECOR subgroup B2 strains suggested that the virulent E. coli strains causing bacteremia in cancer patients are closely related to ECOR B2 strains. The presence in the E. coli population surveyed of a strong linkage disequilibrium, and especially of a highly significant correlation between PFGE and RAPD genetic distances, confirms that clonal propagation has a major impact on the E. coli population structure. Nevertheless, low bootstrap values in the phylogenetic tree suggested that frequent genetic exchange inhibits the individualization of discrete genetic lineages, which are stable on an evolutionary scale.

Dural puncture and corticotherapy as risks factors for cerebral venous sinus thrombosis

Dural puncture with corticosteroid could be a predisposing factor for cerebral venous thrombosis (CVT). A 35-year-old woman using oral contraception was treated with corticosteroid epidural infiltration for L5 radiculalgia. The following day a postural headache developed and accidental dural puncture was suspected. Four days later, she presented with fever and consciousness impairment requiring mechanical ventilation. Magnetic resonance angiography (MRA) confirmed thrombosis of the superior sagittal sinus. Recanalization was observed three weeks later and the patient fully recovered. Blood tests for thrombophilia showed a moderate decrease in the C protein level (chronometric activity 44%, N = 65-130). CVT has been reported after spinal anaesthesia or peridural anaesthesia with accidental puncture. After dural puncture the decrease of cerebrospinal fluid pressure induces a rostrocaudal sagging effect with traumatic damage to the fragile venous endothelial wall, and may trigger a venous vasodilatation with resultant stasis. CVT has also been described in patients after lumbar puncture and oral corticoid treatment for multiple sclerosis and after corticosteroid intrathecal infiltration. Therefore, corticosteroids can be considered as a potential additional procoagulant stimuli.

Structural Properties of Asymmetric Mixed-Chain Phosphatidylethanolamine Films

By use of Langmuir isotherms and atomic force microscopy (AFM) experiments, we compare the structural properties of an asymmetric 1-palmitoyl-2-oleoyl-glycero-3-phosphoethanolamine (PE 181/160) film sampled at 21 degrees C on mica plates with those of a film composed of a mixture of the related saturated phospholipid (PE 160/160) and unsaturated phospholipid (PE 181/181). From PE 181/160, the Pi-A curve obtained presents a plateau (35 mN/m) where AFM images allowed us to determine a nucleation process, which governs the growth of condensed domains. This surface transition is interpreted as reflecting hydrophobic interactions mainly between the alkyl chains of the molecules. Moreover Pi-A curves of a mixture (v/v) of the two related saturated and unsaturated phospholipids (PE 160/160 and PE 181/181) show a "double plateau" (50 and 54 mN/m) and we have characterized a partial surface demixing at every surface pressure. Finally we show that only PE 181/160 is able to form bilayers above the collapse pressure. Copyright 1999 Academic Press.

Modulated release of IdUrd from poly (D,L-lactide-co-glycolide) microspheres by addition of poly (D,L-lactide) oligomers

This paper reports the release characteristics of a radiosensitizer, 5-iodo-2'-deoxyuridine (IdUrd), from poly (D,L-lactide-co-glycolide) 50: 50 (PLGA) microparticles obtained by a phase separation technique. Poly (D,L-lactide) oligomers (D,L-PLA) were incorporated into the PLGA matrix in order to accelerate the overall drug release rate and regulate the triphasic release profile exhibited by the standard PLGA microparticles. For D,L-PLA (800), the burst effect was large and the IdUrd release was complete between 28 and 35 days. These results were attributed to rapid pore formation on the periphery of the microsphere in the early stages of incubation, due to hydrosolubility of the smallest oligomers (D,L-PLA (800)). In the case of D,L-PLA (1,100), drug release occurred over a six week period, the standard time course of conventional radiation therapy. The period during which the radiosensitizer was incorporated in human brain tumor cell nuclei after its entrapment in biodegradable microspheres was determined by using an organotypical tissue culture. The presence of radiosensitizer in the DNA of tumor cell nuclei was detected by immunohistochemical labelling of tumor fragments. IdUrd release from standard microspheres (7+/-0.5 weeks) was longer than from oligomer-containing batches. For D,L-PLA (800)-containing microspheres, the radiosensitizer was entirely released within 4. 5+/-0.5 weeks. The microspheres containing D,L-PLA (1,100) allowed an IdUrd release over a 5 to 6 week period. The ex vivo data were consistent with the in vitro findings in terms of release duration.

Serum is more suitable than whole blood for diagnosis of systemic candidiasis by nested PCR

PCR assays for the diagnosis of systemic candidiasis can be performed either on serum or on whole blood, but results obtained with the two kinds of samples have never been formally compared. Thus we designed a nested PCR assay in which five specific inner pairs of primers were used to amplify specific targets on the rRNA genes of Candida albicans, C. tropicalis, C. parapsilosis, C. krusei, and C. glabrata. In vitro, the lower limit of detection of each nested PCR assay was 1 fg of purified DNA from the corresponding Candida species. In rabbits with candidemia of 120 minutes' duration following intravenous (i.v.) injection of 10(8) CFU of C. albicans, the sensitivities of the PCR in serum and whole blood were not significantly different (93 versus 86%). In other rabbits, injected with only 10(5) CFU of C. albicans, detection of candidemia by culture was possible for only 1 min, whereas DNA could be detected by PCR in whole blood and in serum for 15 and 150 min, respectively. PCR was more often positive in serum than in whole blood in 40 culture-negative samples (27 versus 7%; P < 0.05%). Lastly, experiments with rabbits injected i.v. with 20 or 200 microgram of purified C. albicans DNA showed that PCRs were positive in serum from 30 to at least 120 min after injection, suggesting that the clearance of free DNA is slow. These results suggest that serum is the sample of choice, which should be used preferentially over whole blood for the diagnosis of systemic candidiasis by PCR.

A Convenient Apparatus to Determine the Zeta Potential of Grains by Electro-Osmosis

A simple experimental setup for the measurement of electro-osmotic flow through porous media by direct weighing is described. Potential instead of current measurement allows the determination of zeta potential, even in the presence of significant surface conduction. Flow equations valid for porous media composed of monodisperse spheres are used successfully for isotropic packed beds made with randomly shaped and sized Nylon grains. The measured zeta potentials are in agreement with those deduced from electrophoresis. Copyright 1999 Academic Press.

Adenovirus-mediated gene transfer in dog prostate: a preclinical study of a relevant model system for gene therapy of human prostatic cancer

This present study evaluates the potential of adenovirus-mediated gene transfer (AMGT) to the prostate of normal laboratory beagles. Many morphological and histological similarities can be noted between dog and human prostate. Moreover, dogs can spontaneously develop prostate cancer with a clinical and biological outcome identical to that in man. Firstly we showed the capacity of human adenovirus to infect canine prostatic cells in vitro. Secondly, we injected transrectally in the dogs' prostates 2x10(9) plaque forming units of a first generation recombinant adenovirus vector harboring the reporter gene beta-galactosidase (AdRSVbetagal). Seven days after the adenoviral delivery, we observed expression of the transgene in both prostates, and exclusively in epithelial cells. Despite a cellular and a humoral immune response, the infusion appeared safe, since the dogs had no fever and presented no urinary symptoms. This study constitutes the first evaluation of AMGT in dog prostate and provides a basis for gene therapy treatment of prostate carcinoma-bearing patients.

Squamous cell carcinomas after allogeneic bone marrow transplantation for aplastic anemia: further evidence of a multistep process

BACKGROUND

Secondary solid tumors are rare events occurring in patients who underwent allogeneic marrow transplantation for aplastic anemia and Fanconi's anemia. Human herpes virus 8 (HHV8), Epstein-Barr virus (EBV), and human papillomaviruses (HPV) sequences have been found in squamous cell carcinoma (SCC) occurring in organ transplant recipients. The tumor suppressor gene p53 has been strongly linked to the occurrence of SCC in the nonimmunocompromised population.

PATIENTS AND METHODS

In eight patients with SCC, we searched for HHV8, EBV, varicella zoster virus, adenovirus, and HPV sequences from DNA extracted from selected areas of SCC. We also looked for p53 expression in those specimens as well as the presence of anti-p53 antibodies in the serum of these patients at the onset of SCC.

RESULTS

In one patient, we found the presence of both HHV8 and EBV sequences, and in another patient we found HPV16 sequences. All five tumors that could be studied disclosed evidence of p53 accumulation, but none of the eight patients had anti-p53 antibodies in the sera.

CONCLUSION

SCC developing in marrow transplant recipients seems to occur via a multistep process. Genetic predisposition may be present, as in patients with Fanconi's anemia. Transplantation-related factors, such as irradiation and chronic graft-versus-host disease, also have a role. In this article, we add two more potent risk factors: p53 alteration(s) and in some cases the presence of oncogenic viruses.

[Validation of a model of psychosocial determinants of occupational health of geriatric nurses]

The purpose of this study was to verify a model of relationships between psychosocial factors and health for 8066 francophone nurses working in geriatric care in Québec. A random sample of 1990 subjects was drawn and a participation rate of 77.9% and 55% was obtained for the two-time study taken twelve months apart. Based on the theory of Maddi and Kobasa (1984), the model was reproduced for the two-time periods with the aid of structural equations. The analyses showed that three variables exert a direct influence on psychological distress: professional burnout, occupational stressors and hardiness. Also, variables have a direct effect on burnout: listed in order of importance, these are hardiness, occupational stressors, work support, active strategies of coping and employment status. In dealing with the work stressors, the nurses who are hardy make use of active strategies of coping and look for support form their colleagues. The results of the study help to better understand the psychological and social resources that best favor adaptation of working women in highly demanding work environments. The fallout of the study converges towards the quality of life of helping professionals and towards the cost and quality of health and social services.