Occlusal Loading Effect on Stress Distribution of Endodontically Treated Teeth: Finite Element Analysis Study.

AIM: Evaluate the influence of occlusal loading on the stress distribution of endodontically treated teeth after root canal preparation with different file's sizes and tapers by means of finite element analysis. METHODOLOGY: Seven three-dimensional models of a single-rooted, single-canal lower second premolar were established, one healthy control and six endodontically treated and restored models. The shape of root canal preparations followed file configurations 30/.05, 30/.09, 35/.04, 35/.06, 40/.04, and 40/.06. Von- Mises equivalent stresses were calculated by applying 30 N, 90 N and 270 N loads to the buccal cusp tip, each one at 90º, 45º and 20º angles from the occlusal plane simulating occlusion, dental interference and laterality, respectively. RESULTS: 45º loading was more prone to formation of higher stress values. The simulation of occlusion and laterality resulted in maximum stress areas located at the inner side of the root curvature, while under occlusal interference they were on the lingual surface over the tooth's long axis. CONCLUSIONS: The angulation of occlusal loading and magnitude were determinants for stress distribution on dental structure. Both variations of size and taper were not determinants for the increase in the maximum stress areas.

Evaluation of altered environmental conditions as a decontamination approach for nonspore-forming biological agents.

AIMS: The purpose of this study was to evaluate the effects of altered environmental conditions on the persistence of Francisella tularensis bacteria and Venezuelan equine encephalitis virus (VEEV), on two material types. METHODS AND RESULTS: Francisella tularensis (F.t.) and VEEV were inoculated (c. 1 × 108 colony-forming units or PFU), dried onto porous and nonporous fomites (glass and paper), and exposed to combinations of altered environmental conditions ranging from 22 to 60°C and 30 to 75% relative humidity (RH). Viability of test organism was assessed after contact times ranging from 30 min to 10 days. Inactivation rates of F.t. and VEEV increased as both temperature and/or RH were increased. Greater efficacy was observed for paper as compared to glass for both test organisms. CONCLUSIONS: The use of elevated temperature and RH increased rate of inactivation for both organisms and greater than six log reduction was accomplished in as little as 6 h by elevating temperature to approximately 60°C. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide information for inactivation of nonspore-forming select agents using elevated temperature and humidity which may aid incident commanders following a biological contamination incident by providing alternative methods for remediation.

Correction to: Automated IMRT planning in Pinnacle-A study in head-and-neck cancer.

Correction to: Strahlenther Onkol 2017 https://doi.org/10.1007/s00066-017-1187-9 Unfortunately, parts of the 'Materials and Methods section' and a sentence in the 'Discussion section' had to be corrected.On page 3, left column, the complete first paragraph was corrected and now reads as follows:Auto-P.

Automated IMRT planning in Pinnacle : A study in head-and-neck cancer.

PURPOSE: This study evaluates the performance and planning efficacy of the Auto-Planning (AP) module in the clinical version of Pinnacle 9.10 (Philips Radiation Oncology Systems, Fitchburg, WI, USA). METHODS AND MATERIALS: Twenty automated intensity-modulated radiotherapy (IMRT) plans were compared with the original manually planned clinical IMRT plans from patients with oropharyngeal cancer. RESULTS: Auto-Planning with IMRT offers similar coverage of the planning target volume as the original manually planned clinical plans, as well as better sparing of the contralateral parotid gland, contralateral submandibular gland, larynx, mandible, and brainstem. The mean dose of the contralateral parotid gland and contralateral submandibular gland could be reduced by 2.5 Gy and 1.7 Gy on average. The number of monitor units was reduced with an average of 143.9 (18%). Hands-on planning time was reduced from 1.5-3 h to less than 1 h. CONCLUSIONS: The Auto-Planning module was able to produce clinically acceptable head and neck IMRT plans with consistent quality.

Inactivation of Burkholderia pseudomallei on environmental surfaces using spray-applied, common liquid disinfectants.

UNLABELLED: Five commercially available liquid antimicrobials were evaluated for their ability to decontaminate common environmental surface materials, contaminated with Burkholderia pseudomallei, using a spray-based disinfectant delivery procedure. Tests were conducted at both an ambient temperature (c. 20°C) and a lower temperature (c. 12°C) condition. Nonporous materials (glass and aluminium) were more easily decontaminated than porous materials (wood, concrete and carpet). Citric acid (1%) demonstrated poor efficacy in all test conditions. Bleach (pH-adjusted), ethanol (70%), quaternary ammonium and PineSol®, demonstrated high (>6 log10 reduction) efficacies on glass and aluminium at both temperatures, but achieved varying results for wood, carpet and concrete. Temperature had minimal effect on decontamination efficacy during these tests. SIGNIFICANCE AND IMPACT OF THE STUDY: Much of the antimicrobial efficacy data for pathogenic micro-organisms are generated with testing that utilizes hard nonporous surface materials. These data are not directly translatable for decontaminant selection following an incident whereby complex and porous environmental surfaces are contaminated. This study presents efficacy data for spray-applied antimicrobial liquids, when used to decontaminate common environmental surfaces contaminated with Burkholderia pseudomallei. These data can help responders develop effective remediation strategies following an environmental contamination incident involving B. pseudomallei.

Environmental persistence of vaccinia virus on materials.

Smallpox is caused by the variola virus, and ranks as one of the most serious diseases that could originate from a biological weapon. However, limited data exist on the persistence of variola and related viruses on materials (that may act as fomites), under controlled environmental conditions. To fill these data gaps, we determined the persistence of the vaccinia virus (an established surrogate for the variola virus) as a function of temperature, relative humidity and material. Experiments were conducted with vaccinia virus in a freeze-dried form, using four materials under four sets of environmental conditions. After elapsed times ranging from 1 to 56 days, the virus was extracted from small coupons and quantified via plaque-forming units (PFU). The vaccinia virus was most persistent at low temperature and low relative humidity, with greater than 10(4) PFU recovered from glass, galvanized steel and painted cinder block at 56 days (equivalent to only a c. 2 log reduction). Thus, vaccinia virus may persist from weeks to months, depending on the material and environmental conditions. This study may aid those responsible for infection control to make informed decisions regarding the need for environmental decontamination following the release of an agent such as variola.

The effects of environmental conditions on persistence and inactivation of Brucella suis on building material surfaces.

AIMS: The purpose of this study was to evaluate the effects of environmental conditions and material type on persistence and inactivation of Brucella suis. METHODS AND RESULTS: Brucella suis (approx. 1 × 10(8) CFU) was spiked onto surfaces (glass, aluminium and wood) by liquid inoculation. Persistence was evaluated over 56 days at 22 ± 2°C, 40 ± 15% r.h. and 5 ± 3°C, 30 ± 15% r.h. In addition, three readily available decontaminants (pH-adjusted bleach, 70% ethanol and 1% citric acid) were evaluated for their effectiveness at inactivating Br. suis on these materials. Decontaminations were conducted following 0 and 28 days exposure to the two conditions. Results indicated that Br. suis can persist on environmental surfaces for at least 56 days. Persistence was highest at low temperature. Decontamination was most challenging on wood with all three decontaminants. CONCLUSIONS: Following a Br. suis contamination incident, passive decontamination (through attenuation) may not be feasible, as this organism can persist for months. In addition, the results suggest that some sporicidal decontaminants may be ineffective on materials such as wood, even for vegetative biological agents such as Br. suis. SIGNIFICANCE AND IMPACT OF STUDY: This study aids incident commanders and remediation experts to make informed decisions regarding decontamination after a biological contamination incident.

Catching errors with in vivo EPID dosimetry.

The potential for detrimental incidents and the ever increasing complexity of patient treatments emphasize the need for accurate dosimetric verification in radiotherapy. For this reason, all curative treatments are verified, either pretreatment or in vivo, by electronic portal imaging device (EPID) dosimetry in the Radiation Oncology Department of The Netherlands Cancer Institute-Antoni van Leeuwenhoek hospital, Amsterdam, The Netherlands. Since the clinical introduction of the method in January 2005 until August 2009, treatment plans of 4337 patients have been verified. Among these plans, 17 serious errors were detected that led to intervention. Due to their origin, nine of these errors would not have been detected with pretreatment verification. The method is illustrated in detail by the case of a plan transfer error detected in a 5 x 5 Gy intensity-modulated radiotherapy (IMRT) rectum treatment. The EPID reconstructed dose at the isocenter was 6.3% below the planned value. Investigation of the plan transfer chain revealed that due to a network transfer error, the plan was corrupted. 3D analysis of the acquired EPID data revealed serious underdosage of the planning target volume: On average 11.6%, locally up to 20%. This report shows the importance of in vivo (EPID) dosimetry for all treatment plans as well as the ability of the method to assess the dosimetric impact of deviations found.

Three-dimensional heart dose reconstruction to estimate normal tissue complication probability after breast irradiation using portal dosimetry.

Irradiation of the heart is one of the major concerns during radiotherapy of breast cancer. Three-dimensional (3D) treatment planning would therefore be useful but cannot always be performed for left-sided breast treatments, because CT data may not be available. However, even if 3D dose calculations are available and an estimate of the normal tissue damage can be made, uncertainties in patient positioning may significantly influence the heart dose during treatment. Therefore, 3D reconstruction of the actual heart dose during breast cancer treatment using electronic imaging portal device (EPID) dosimetry has been investigated. A previously described method to reconstruct the dose in the patient from treatment portal images at the radiological midsurface was used in combination with a simple geometrical model of the irradiated heart volume to enable calculation of dose-volume histograms (DVHs), to independently verify this aspect of the treatment without using 3D data from a planning CT scan. To investigate the accuracy of our method, the DVHs obtained with full 3D treatment planning system (TPS) calculations and those obtained after resampling the TPS dose in the radiological midsurface were compared for fifteen breast cancer patients for whom CT data were available. In addition, EPID dosimetry as well as 3D dose calculations using our TPS, film dosimetry, and ionization chamber measurements were performed in an anthropomorphic phantom. It was found that the dose reconstructed using EPID dosimetry and the dose calculated with the TPS agreed within 1.5% in the lung/heart region. The dose-volume histograms obtained with EPID dosimetry were used to estimate the normal tissue complication probability (NTCP) for late excess cardiac mortality. Although the accuracy of these NTCP calculations might be limited due to the uncertainty in the NTCP model, in combination with our portal dosimetry approach it allows incorporation of the actual heart dose. For the anthropomorphic phantom, and for fifteen patients for whom CT data were available to test our method, the average difference between the NTCP values obtained with our method and those resulting from the dose distributions calculated with the TPS was 0.1% +/- 0.3% (1 SD). Most NTCP values were 1%-2% lower than those obtained using the method described by Hurkmans et al. [Radiother. Oncol. 62, 163-171 (2002)], using the maximum heart distance determined from a simulator image as a single pre-treatment parameter. A similar difference between the two methods was found for twelve patients using in vivo EPID dosimetry; the average NTCP value obtained with EPID dosimetry was 0.9%, whereas an average NTCP value of 2.2% was derived using the method of Hurkmans et al. The results obtained in this study show that EPID dosimetry is well suited for in vivo verification of the heart dose during breast cancer treatment, and can be used to estimate the NTCP for late excess cardiac mortality. To the best of our knowledge, this is the first study using portal dosimetry to calculate a DVH and NTCP of an organ at risk.

Clinical experience with EPID dosimetry for prostate IMRT pre-treatment dose verification.

The aim of this study was to demonstrate how dosimetry with an amorphous silicon electronic portal imaging device (a-Si EPID) replaced film and ionization chamber measurements for routine pre-treatment dosimetry in our clinic. Furthermore, we described how EPID dosimetry was used to solve a clinical problem. IMRT prostate plans were delivered to a homogeneous slab phantom. EPID transit images were acquired for each segment. A previously developed in-house back-projection algorithm was used to reconstruct the dose distribution in the phantom mid-plane (intersecting the isocenter). Segment dose images were summed to obtain an EPID mid-plane dose image for each field. Fields were compared using profiles and in two dimensions with the y evaluation (criteria: 3%/3 mm). To quantify results, the average gamma (gamma avg), maximum gamma (gamma max), and the percentage of points with gamma < 1(P gamma < 1) were calculated within the 20% isodose line of each field. For 10 patient plans, all fields were measured with EPID and film at gantry set to 0 degrees. The film was located in the phantom coronal mid-plane (10 cm depth), and compared with the back-projected EPID mid-plane absolute dose. EPID and film measurements agreed well for all 50 fields, with (gamma avg) =0.16, (gamma max)=1.00, and (P gamma < 1)= 100%. Based on these results, film measurements were discontinued for verification of prostate IMRT plans. For 20 patient plans, the dose distribution was re-calculated with the phantom CT scan and delivered to the phantom with the original gantry angles. The planned isocenter dose (plan(iso)) was verified with the EPID (EPID(iso)) and an ionization chamber (IC(iso)). The average ratio, (EPID(iso)/IC(iso)), was 1.00 (0.01 SD). Both measurements were systematically lower than planned, with (EPID(iso)/plan(iso)) and (IC(iso)/plan(iso))=0.99 (0.01 SD). EPID mid-plane dose images for each field were also compared with the corresponding plane derived from the three dimensional (3D) dose grid calculated with the phantom CT scan. Comparisons of 100 fields yielded (gamma avg)=0.39, gamma max=2.52, and (P gamma < 1)=98.7%. Seven plans revealed under-dosage in individual fields ranging from 5% to 16%, occurring at small regions of overlapping segments or along the junction of abutting segments (tongue-and-groove side). Test fields were designed to simulate errors and gave similar results. The agreement was improved after adjusting an incorrectly set tongue-and-groove width parameter in the treatment planning system (TPS), reducing (gamma max) from 2.19 to 0.80 for the test field. Mid-plane dose distributions determined with the EPID were consistent with film measurements in a slab phantom for all IMRT fields. Isocenter doses of the total plan measured with an EPID and an ionization chamber also agreed. The EPID can therefore replace these dosimetry devices for field-by-field and isocenter IMRT pre-treatment verification. Systematic errors were detected using EPID dosimetry, resulting in the adjustment of a TPS parameter and alteration of two clinical patient plans. One set of EPID measurements (i.e., one open and transit image acquired for each segment of the plan) is sufficient to check each IMRT plan field-by-field and at the isocenter, making it a useful, efficient, and accurate dosimetric tool.

[Hepatitis A seroprevalence in HIV-infected patients]. / Séroprévalence de l'hépatite A chez des patients infectés par le VIH.

OBJECTIVE: The authors had for aim to prospectively study the hepatitis A seroprevalence of an HIV-infected population, followed-up in an outpatient clinic (CISIH Strasbourg). DESIGN: Blood tests were performed on all patients from September 2003 to March 2004 to screen for hepatitis A (total antibodies with Elisa). RESULTS: The overall seroprevalence was 219/514 (56.6%), similar in male and female patients. It increased with age, especially in European patients (P = 0.003). The seroprevalence was lower in European subjects: 46.3% (while it reached 100% in sub-Saharan Africans), the prevalence was similar whatever the HIV risk group (46% in homosexual as well as in heterosexual patients, 44% in intravenous drug users). Hepatitis B or C co-infection did not increase the seroprevalence of hepatitis A. The hepatitis A seroprevalence was similar in various CD4 T cell count categories. CONCLUSIONS: Our results stress the utility of hepatitis A serology in HIV-infected patients (more than 50% of European patients are non immune), and the importance of assessing hepatitis A vaccination.

The long-term stability of amorphous silicon flat panel imaging devices for dosimetry purposes.

This study was carried out to determine the stability of the response of amorphous silicon (a-Si)-flat panel imagers for dosimetry applications. Measurements of the imager's response under reference conditions were performed on a regular basis for four detectors of the same manufacturer. We found that the ambient temperature influenced the dark-field, while the gain of the imager signal was unaffected. Therefore, temperature fluctuations were corrected for by applying a "dynamic" darkfield correction. This correction method also removed the influence of a small, irreversible increase of the dark-field current, which was equal to 0.5% of the dynamic range of the imager per year and was probably caused by mild radiation damage to the a-Si array. By applying a dynamic dark-field correction, excellent stability of the response over the entire panel of all imagers of 0.5% (1 SD) was obtained over an observation period up to 23 months. However, two imagers had to be replaced after several months. For one imager, an image segment stopped functioning, while the image quality of the other imager degraded significantly. We conclude that the tested a-Si EPIDs have a very stable response and are therefore well suited for dosimetry. We recommend, however, applying quality assurance tests dedicated to both imaging and dosimetry.

[Evaluation of two commercial enzyme immunoassays for diagnosis of hepatitis C in the conditions of a virology laboratory]. / Evaluation de deux trousses commerciales EIA pour le diagnostic de l'hépatite C dans les conditions d'un laboratoire de virologie.

BACKGROUND: Most studies which evaluate antibody detection assays are conducted on blood donors specimens, i.e healthy individuals. Sera collected in patients, vs healthy individuals, can make serological tests difficult because of possible non specific reactions interfering with serological tests. The aim of this work was to compare the specificity and the sensitivity of two commercial automated assays for the detection of hepatitis C virus antibody, Monolisa anti-HCV Plus on the Evolis automate (Biorad) and Axsym anti-HCV 3.0 (Abbott). PATIENTS AND METHOD: The prospective study of specificity included 2020 routine serum samples sent to our virology laboratory. The sensitivity was established with eight commercially available HCV seroconversion panels. RESULTS: The Monolisa and the Axsym assays showed a specificity of 99.64 and 99.12%, respectively. Of 49 specimens from eight commercially available HCV seroconversion panels, the number of positive results was 21 and 24 for the two tests, respectively. CONCLUSION: A statistical analysis of specificity and sensitivity results proved no significant difference between the two tests. Nevertheless, the Monolisa kits could be preferred for its more homogeneous sensitivity than the Axsym test and for its apparent better specificity. The final choice of a kit should also take into account the easiness to perform and an optimal integration in the usual practice of the concerned laboratory.

[Immunoblot in the serological diagnosis of hepatitis C virus infection]. / Intérêt de l'immunoblot dans l'évaluation du statut sérologique vis-à-vis de l'hépatite C.

The objective of the study was to assess three immunoblot assays, the Deciscan HCV Plus, the Riba and the Inno-Lia, on 44 discordant samples with three EIA kits. These immunoblots were considered as confirmation reagents. A result was considered as a false positive by anti-HCV antibody assay if the three immunoblots were negative or if two immunoblots were negative with the third being indeterminate and a negative virological genomic diagnosis observed on all the samples. The result was positive if at least two immunoblots out of three were positive. Thus, 34 samples were considered as false positive and ten samples were excluded because it was impossible to conclude between true or false positive result. The 44 discordant results were never confirmed as positive by the use immunoblot or PCR. The three immunoblots were negative for half of the samples and two immunoblots and one indeterminate were observed for 77% of the samples. The false positive results by the Monolisa assay were more often found indeterminate with the Deciscan assay than with the other immunoblots. That was also checked for Vitros/Riba pair. One of the explanations could be the use of common antigens for the reagents from the same manufacturer. The Inno-Lia test is the most specific immunoblot according to the results obtained in our study.

Peridinin chlorophyll a protein: relating structure and steady-state spectroscopy.

Peridinin chlorophyll a protein (PCP) from Amphidinium carterae has been studied using absorbance (OD), linear dichroism (LD), circular dichroism (CD), fluorescence emission, fluorescence anisotropy, fluorescence line narrowing (FLN), and triplet-minus-singlet spectroscopy (T-S) at different temperatures (4-293 K). Monomeric PCP binds eight peridinins and two Chls a. The trimeric structure of PCP, resolved at 2 A [Hofmann et al. (1996) Science 27, 1788-1791], allows modeling of the Chl a-protein and Chl a-Chl a interactions. The FLN spectrum shows that Chl a is not or is very weakly hydrogen-bonded and that the central magnesium of the emitting Chl a is monoligated. Simulation of the temperature dependence of the absorption spectra indicates that the Huang-Rhys factor, characterizing the electron-phonon coupling strength, has a value of approximately 1. The width of the inhomogeneous distribution function is estimated to be 160 cm(-)(1). LD experiments show that the two Chls a in PCP are essentially isoenergetic at room temperature and that a substantial amount of PCP is in a trimeric form. From a comparison of the measured and simulated CD, it is concluded that the interaction energy between the two Chls a within one monomer is very weak, <10 cm(-)(1). In contrast, the Chls a appear to be strongly coupled to the peridinins. The 65 cm(-)(1) band that is visible in the low-frequency region of the FLN spectrum might indicate a Chl a-peridinin vibrational mode. The efficiency of Chl a to peridinin triplet excitation energy transfer is approximately 100%. On the basis of T-S, CD, LD, and OD spectra, a tentative assignment of the peridinin absorption bands has been made.

Increasing the number of hepatitis B vaccine injections augments anti-HBs response rate in HIV-infected patients. Effects on HIV-1 viral load.

Preventing hepatitis B by vaccination is essential in HIV-infected patients (higher progression rate of HBV infection to chronicity, lower rate of serum HBe Ag loss). However, it has been shown a decreased anti-HBs response in these individuals after a standard vaccination (3 doses of 20 micrograms). Thus, we tested the hypothesis that doubling the number of hepatitis B vaccine injections might increase anti-HBs response rate. HIV-infected patients with CD4 > 200/microliter, who were on stable antiretroviral treatment, as well as seronegative for HBV markers, and who have never been vaccinated against HBV, were given 3 intramuscular injections of Genhevac B 20 micrograms at 1 month intervals. Initial non responders were given 3 additional monthly injections. Anti-HBs titer was followed. We also evaluated the effects on HIV-1 viral load. Twenty patients with a median CD4 cell count of 470/microliter were enrolled. The response rate after three 20 micrograms injections was 55% (11/20), lower in individuals with CD4 between 200 and 500/microliter (4/12 = 33.3%), compared to patients with CD4 above 500/microliter (7/8 = 87.5%, P = 0.02). Among 9 initial non-responders, only 2 did not respond to 3 additional doses; thus, the overall response rate was 90% (18/20). Geometric mean titers of anti-HBs were 133 IU/l and 77.5 IU/l, after 3 and 6 Genhevac doses, respectively (P = 0.38). One year later, only 10/17 (58.8%) patients had protective anti-HBs. Five patients experienced a significant viral load increase, transient in 3 cases. These preliminary results suggest that doubling the number of hepatitis B vaccinations in HIV-infected patients might significantly improve anti-HBs response rate; however, close monitoring of anti-HBs is necessary because of its short-lived persistence. The effects on HIV-1 viral load are limited.

[Retrospective study of the value of the RIBA-3 test in 68 patients with discordant serologies with regard to hepatitis C obtained with third generation ELISA tests. Is there still a value in RIBA-3?]. / Etude rétrospective de l'intérêt du test RIBA-3 pour 68 cas de sérologies discordantes vis-à-vis du virus de l'hépatite C obtenues avec des tests ELISA de 3e génération. Reste-t-il un intérêt au RIBA-3?

The aim of the present study is to evaluate the ability of RIBA-3 to resolve cases with controversial ELISA results, since modifications have been introduced by the manufacturer in July 1997 to analyse immunoblot patterns. Sera from 68 patients are studied: 49 controversial cases Ortho/Murex, 17 Ortho/Abbott and 2 cases tested by the three ELISA kits. Indeterminate patterns by ELISA assays remain unresolved in 65% of the samples. RIBA analysis performed in patients with controversial results Ortho/Murex seems to reveal a lack in sensitivity of the Murex kit, but does not show differences in the specificity between these two immunoassays. The RIBA patterns among the samples with Ortho/Abbott controversial results do not demonstrate any discrepancy in the sensitivity of these ELISA tests but it appears that Ortho could be less specific. Our data need to be further confirmed by the analysis of more samples. At last, when the ELISA result is included in the grayzone, the RIBA pattern is generally indeterminate and it is negative in other cases. Finally, the controversial ELISA results, that are mainly found in patients with severe immunosuppression, remain indeterminate depending on the RIBA test. Moreover, the immunoblot is less sensitive and more expensive than any other HCV ELISA test, so there is no convenience to use it for confirmation of a preliminary positive or indeterminate screening.

[Prenatal diagnosis of viral infections. A two year study in Strasbourg]. / Diagnostic prénatal des infections virales. Bilan de deux années d'activité à Strasbourg.

We report here the results of a 2-year study on the prenatal diagnosis of viral infections in Strasbourg. This screening was carried out by virus isolation, by PCR assay, or by detection of IgM fetal antibody for 98 pregnant women at risk of transmitting one of the viruses that causes fetal disease such as parvovirus B19 (B19), Herpesviruses [cytomegalovirus (CMV), varicella-zoster virus, herpes simplex virus] and rubella virus. A viral etiology was proven in 7 out 98 cases: PCR applied to B19 DNA detection was positive in 5 amniotic fluids (AF), 2 fetal serums and one ascitic liquid. The diagnosis of 2 cases of CMV infection was obtained by both PCR and virus isolation in AF from twins fetuses. The detection of specific IgM in maternal serum or fetal serum is useful to achieve the diagnosis but serological tests on other samples have no efficiency. No virus was found in any other specimen, but the genome of Toxoplasma gondii was detected by PCR in 1 of 17 AF samples analyzed at the Institut de Parasitologie. These findings show that PCR assay is a sensitive method for the positive diagnosis of intrauterine infection and promises to careful follow-up of the pregnancy.

[A case report of post-rubella myelitis in an adult]. / A propos d'un cas de myélite post-rubéolique chez l'adulte.

Neurological complications following rubella are only rarely encountered. We report a case of isolated myelitis. A 44-year-old healthy female suffered from an erythematous macular rash which rapidly cleared. However, the following days, dysuria initiated hospitalization. On admission, she was febrile but alert and in normal mental status. General physical examination was quite unremarkable. Four days later, she suffered from acute urinary retention, fecal retention and vaginal hypoesthesia. Routine laboratory data, chest skull and spinal column X-rays were unremarkable. The sterile cerebrospinal fluid contained 30 lymphocytes/mm3, 0.48 g/ml of protein but normal amount of glucose. Rubella antibody titers showed a significant elevation and specific IgM were detected by immunocapture. Improvement was rapid and recovery was uneventful except a mild vaginal hypoesthesia that persisted 5 weeks later. Diffuse myelitis occurring shortly after rubella vaccination have also been described. The immunopathological mechanisms by which involvement of the nervous system occurs is far from clear. Little is known about the pathogenesis of post-vaccination myelitis and although the mecanism of sensitization and the specific neural antigens are not known, post-infectious and post-vaccinal myelitis are thought to share a common pathogenic basis.

Surface areas and packing constraints in POPC C (12)EO (n) membranes. A time-resolved fluorescence study.

The surface area occupied by nonionic detergents of the type C(12)EO(n) (n = 1-8) in POPC C (12)EO (n) mixed membranes was studied by means of time-resolved resonance energy transfer (RET) between the fluorescent probe molecules NBD-PE and rhodamine-PE. The area data were interpreted within the frame of Israelachvili's concept of packing constraints yielding the critical packing parameter, f, as a measure of the asymmetry of the molecular shape of the membrane constituents. The asymmetry of the molecular shape of the detergent increases with the ethylene oxide chain length and correlates with the potency of the detergent to solubilize the bilayers and the reduction of the DPH order parameter. For n = 1-3, the membrane surface was found to expand by 0.25-0.30 nm(2) per incorporated C(12)EO(n) molecule. This value corresponds to the cross section of one hydrocarbon chain in liquid-crystalline phases. On increasing n from n = 4 to n = 8 the net area per detergent molecule increases from 0.43 nm(2) to 1.16 nm(2). These surface requirements are consistent with a disordered, coiled conformation of the EO-chains hydrated with up to two water molecules per ethylene oxide unit. For n > 5 the limiting mole fraction of the bilayer saturation was deduced from the f-data in the two-component bilayer. DPH and NBD-PE fluorescence lifetime data are discussed to give an indication of the accessibility of the probe environment to water molecules.