Postmortem fetal imaging: prospective blinded comparison of two-dimensional ultrasound with magnetic resonance imaging

OBJECTIVE

To compare the diagnostic rate and accuracy of 3-Tesla (T) postmortem magnetic resonance imaging (PM-MRI) and postmortem ultrasound (PM-US) in an unselected fetal population.

METHODS

We performed prospectively, in a blinded manner, 3-T PM-MRI and PM-US on 160 unselected fetuses at 13-41 weeks of gestation. All imaging was reported according to a prespecified template, for five anatomical regions: brain, thorax, heart, abdomen and spine. The rates of non-diagnostic results for PM-US and PM-MRI were compared and, for results that were diagnostic, we calculated sensitivity, specificity and concordance rates for each anatomical region, using conventional autopsy as the reference standard.

RESULTS

3-T PM-MRI performed significantly better than did PM-US overall and in particular for fetuses ≥ 20 weeks' gestation. Specifically, the non-diagnostic rates for PM-MRI vs PM-US were 4.4% vs 26.9% (7/160 vs 43/160; P < 0.001) for the brain, 5.2% vs 17.4% (8/155 vs 27/155; P < 0.001) for the thorax, 3.8% vs 30.6% (6/157 vs 48/157; P < 0.001) for the heart and 3.2% vs 23.6% (5/157 vs 37/157; P < 0.001) for the abdomen. For the spine, both techniques showed an equally low non-diagnostic rate. When both postmortem imaging techniques were diagnostic, they had similar accuracy, with no difference in sensitivity or specificity, and similar concordance with autopsy (PM-US, 79.5-96.5%; PM-MRI, 81.6-99.1%).

CONCLUSIONS

PM-MRI performed significantly better than PM-US in this unselected population, due mainly to a lower non-diagnostic rate. PM-MRI should remain the first-line imaging investigation for perinatal autopsy, but PM-US could be considered if MRI is not available, albeit with a higher non-diagnostic rate. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

High speed atomic force microscopy to investigate the interactions between toxic Aβ1-42 peptides and model membranes in real time: impact of the membrane composition

Due to an aging population, neurodegenerative diseases have become a major health issue, the most common being Alzheimer's disease. The mechanisms leading to neuronal loss still remain unclear but recent studies suggest that soluble Aβ oligomers have deleterious effects on neuronal membranes. Here, high-speed atomic force microscopy was used to assess the effect of oligomeric species of a variant of Aβ1-42 amyloid peptide on model membranes with various lipid compositions. Results showed that the peptide does not interact with membranes composed of phosphatidylcholine and sphingomyelin. Ganglioside GM1, but not cholesterol, is required for the peptide to interact with the membrane. Interestingly, when they are both present, a fast disruption of the membrane was observed. It suggests that the presence of ganglioside GM1 and cholesterol in membranes promotes the interaction of the oligomeric Aβ1-42 peptide with the membrane. This interaction leads to the membrane's destruction in a few seconds. This study highlights the power of high-speed atomic force microscopy to explore lipid-protein interactions with high spatio-temporal resolution.

Broadband near-infrared astronomical spectrometer calibration and on-sky validation with an electro-optic laser frequency comb

The quest for extrasolar planets and their characterization as well as studies of fundamental physics on cosmological scales rely on capabilities of high-resolution astronomical spectroscopy. A central requirement is a precise wavelength calibration of astronomical spectrographs allowing for extraction of subtle wavelength shifts from the spectra of stars and quasars. Here, we present an all-fiber, 400 nm wide near-infrared frequency comb based on electro-optic modulation with 14.5 GHz comb line spacing. Tests on the high-resolution, near-infrared spectrometer GIANO-B show a photon-noise limited calibration precision of < 10 cms as required for Earth-like planet detection. Moreover, the presented comb provides detailed insight into particularities of the spectrograph such as detector inhomogeneities and differential spectrograph drifts. The system is validated in on-sky observations of a radial velocity standard star (HD221354) and telluric atmospheric absorption features. The advantages of the system include simplicity, robustness and turn-key operation, features that are valuable at the observation sites.

Electron transfer in an acidophilic bacterium: interaction between a diheme cytochrome and a cupredoxin

Acidithiobacillus ferrooxidans, a chemolithoautotrophic Gram-negative bacterium, has a remarkable ability to obtain energy from ferrous iron oxidation at pH 2. Several metalloproteins have been described as being involved in this respiratory chain coupling iron oxidation with oxygen reduction. However, their properties and physiological functions remain largely unknown, preventing a clear understanding of the global mechanism. In this work, we focus on two metalloproteins of this respiratory pathway, a diheme cytochrome c4 (Cyt c4) and a green copper protein (AcoP) of unknown function. We first demonstrate the formation of a complex between these two purified proteins, which allows homogeneous intermolecular electron-transfer in solution. We then mimic the physiological interaction between the two partners by replacing one at a time with electrodes displaying different chemical functionalities. From the electrochemical behavior of individual proteins, we show that, while electron transfer on AcoP requires weak electrostatic interaction, electron transfer on Cyt c4 tolerates different charge and hydrophobicity conditions, suggesting a pivotal role of this protein in the metabolic chain. The electrochemical study of the proteins incubated together demonstrates an intermolecular electron transfer involving the protein complex, in which AcoP is reduced through the high potential heme of Cyt c4. Modelling of the electrochemical signals at different scan rates allows us to estimate the rate constant of this intermolecular electron transfer in the range of a few s-1. Possible routes for electron transfer in the acidophilic bacterium are deduced.

Interaction of Aβ1-42 peptide or their variant with model membrane of different composition probed by infrared nanospectroscopy

Toxicity of Aβ peptides involved in Alzheimer's disease is linked to the interaction of intermediate species with membranes. Nanoscale Infrared Spectroscopy enhances the study of the morphology and the secondary structure of the peptides as fibers or oligomers interacting with membranes of different compositions, with nanometer scale resolution. Membrane models are used to investigate the role of different lipids in their interactions with Aβ peptides. This work clearly brings to light that the presence of cholesterol in membranes is favorable to the interaction with Aβ peptides in oligomers or aggregates.

A tensegrity driven DNA nanopore

Control of transport across membranes, whether natural or synthetic, is fundamental in many biotechnology applications, including sensing and drug release. Mutations of naturally existing protein channels, such as hemolysin, have been explored in the past. More recently, DNA channels with conductivities in the nanosiemens range have been designed. Regulating transport across DNA channels in response to external stimuli remains an important challenge. Previous designs relied on steric hindrance to control the inner diameter of the channel, which resulted in unstable electric signatures. In this paper we introduce a new design to control electric channel conductance of a DNA nanopore. The tensegrity driven mechanism inhibits the flux of small analytes while keeping a tightly controlled ionic transport modulated by the addition of specific DNA sequences. Current signals are clearly defined, with no sign of gating, opening new perspectives in single molecule DNA sensing.

[Tamoxifen induced thromboembolic events in breast cancer. Some possible mechanisms]

Tamoxifen is an antagonist of the oestrogen receptor, used in the treatment of breast cancer. It is known to reduce osteoporotic bone fractures, but it increases the risk of endometrial tumors and venous thromboembolic events (VTEs). VTEs increased significantly during tamoxifen therapy within 3 months of major surgery, immobilization or fracture. Their incidence is associated with patients' risk factors, tumor and tissue induced procoagulation. The mechanisms are still not well known. There is a need for a better understanding in order to develope a prophylactic and therapeutic strategy.

Influence of isomerism on recrystallization and cocrystallization induced by CO2 as an antisolvent

The position of the amine group in aminosalicylic acid has a significant impact not only on polymorph or cocrystal formation but also on the crystal shape during crystallization using CO₂ as an antisolvent.

Probing the kinetics of lipid membrane formation and the interaction of a nontoxic and a toxic amyloid with plasmon waveguide resonance

The kinetics of formation of solid-supported lipid model membranes were investigated using a home-made plasmon waveguide resonance (PWR) sensor possessing enhanced properties relative to classic surface plasmon resonance sensors.

Sub-100 attosecond timing jitter from low-noise passively mode-locked solid-state laser at telecom wavelength

We report on the ultralow timing jitter of the 100 MHz pulse trains generated by two identical passively mode-locked diode-pumped solid-state lasers (DPSSLs) emitting at 1556 nm. Ultralow timing jitter of 83 as (integrated from 10 kHz to 50 MHz) for one laser has been measured with a balanced optical cross-correlator as timing discriminator. Extremely low intensity noise has been measured as well. Several measurement techniques have been used and show similar jitter results. Different possible noise sources have been theoretically investigated and compared to the measured jitter power spectral density. It is found that although the measured integrated jitter is quite low, it is still significantly above the quantum limit in the considered frequency span. Therefore, there is a substantial potential for technical improvements that could make passively mode-locked DPSSL outperform fiber lasers as source of microwaves with low phase noise.

Roles of heat shock factor 1 and 2 in response to proteasome inhibition: consequence on p53 stability

A single heat shock factor (HSF), mediating the heat shock response, exists from yeast to Drosophila, whereas several related HSFs have been found in mammals. This raises the question of the specific or redundant functions of the different members of the HSF family and in particular of HSF1 and HSF2, which are both ubiquitously expressed. Using immortalized mouse embryonic fibroblasts (iMEFs) derived from wild-type, Hsf1(-/-), Hsf2(-/-) or double-mutant mice, we observed the distinctive behaviors of these mutants with respect to proteasome inhibition. This proteotoxic stress reduces to the same extent the viability of Hsf1(-/-)- and Hsf2(-/-)-deficient cells, but through different underlying mechanisms. Contrary to Hsf2(-/-) cells, Hsf1(-/-) cells are unable to induce pro-survival heat shock protein expression. Conversely, proteasome activity is lower in Hsf2(-/-) cells and the expression of some proteasome subunits, such as Psmb5 and gankyrin, is decreased. As gankyrin is an oncoprotein involved in p53 degradation, we analyzed the status of p53 in HSF-deficient iMEFs and observed that it was strongly stabilized in Hsf2(-/-) cells. This study points a new role for HSF2 in the regulation of protein degradation and suggests that pan-HSF inhibitors could be valuable tools to reduce chemoresistance to proteasome inhibition observed in cancer therapy.

Sequential interplay between BAG6 and HSP70 upon heat shock

BAG6/Scythe/Bat3 is a cochaperone of the heat shock protein HSP70 and is involved in various developmental processes, cellular stress and viability. BAG6 interferes with the protein-refolding activity of HSP70 but its precise involvement in proteotoxic stresses remains unknown. We show that BAG6 is required for the accumulation of HSP70 upon heat shock and that conversely, once accumulated, HSP70 leads to the massive and CHIP-independent degradation of BAG6 through the ubiquitin-proteasome system. These reciprocal influences between BAG6 and HSP70 upon heat shock suggest that BAG6 is a central regulator of the cellular content of HSP70. The HSP70-driven degradation of BAG6, following the BAG6-dependent accumulation of HSP70, could allow the protein-refolding activity of HSP70 and limit the extent of its induction.

DNA compaction into new DNA vectors based on cyclodextrin polymer: Surface enhanced Raman spectroscopy characterization

The ability of DNA to bind polycation yielding polyplexes is widely used in nonviral gene delivery. The aim of the present study was to evaluate the DNA compaction with a new DNA vector using Raman spectroscopy. The polyplexes result from an association of a beta-cyclodextrin polymer (polybeta-CD), an amphiphilic cationic connector (DC-Chol or adamantane derivative Ada2), and DNA. The charge of the polymeric vector is effectively controlled by simple addition of cationic connector in the medium. We used surface enhanced Raman spectroscopy (SERS) to characterize this ternary complex, monitoring the accessibility of adenyl residues to silver colloids. The first experiments were performed using model systems based on polyA (polyadenosine monophosphate) well characterized by SERS. This model was then extended to plasmid DNA to study polybeta-CD/Ada2/DNA and polybeta-CD/DC-Chol/DNA polyplexes. The SERS spectra show a decrease of signal intensity when the vector/DNA charge ratio (Z+/-) increases. At the highest ratio (Z+/- = 10) the signal is 6-fold and 3-fold less intense than the DNA reference signal for Ada2 and DC-Chol polyplexes, respectively. Thus adenyl residues have a reduced accessibility as DNA is bound to the vector. Moreover, the SERS intensity variations are in agreement with gel electrophoresis and zeta potential experiments on the same systems. The overall study clearly demonstrates that the cationic charges neutralizing the negative charges of DNA result in the formation of stable polyplexes. In vitro transfection efficiency of those DNA vectors are also presented and compared to the classical DC-Chol lipoplexes (DC-Chol/DNA). The results show an increase of the transfection efficiency 2-fold higher with our vector based on polybeta-CD.

Compact 10-GHz Nd:GdVO4 laser with 0.5-W average output power and low timing jitter

We demonstrate a compact, diode-pumped Nd:GdVO4 laser with a repetition rate of 9.66 GHz and 0.5-W average output power. The laser is passively mode locked with a semiconductor saturable absorber mirror (SESAM), yielding 12-ps-long sech2-shaped pulses. For synchronization of the pulse train to an external reference clock, the SESAM is mounted on a piezoelectric transducer. With an electronic feedback loop of only a few kilohertz loop bandwidth we achieved a rms timing jitter of 146 fs (integrated from 10 Hz to 10 MHz). This is an upper limit because it is mostly limited by the measurement system. The laser setup with a simple linear cavity has a footprint of only 130 mm x 30 mm.

Optical parametric oscillator with a 10-GHz repetition rate and 100-mW average output power in the spectral region near 1.5 mum

We demonstrate a synchronously pumped optical parametric oscillator that emits picosecond pulses at an ~1.55-mum wavelength with a repetition rate as a high as 10 GHz and as much as 100 mW of average power. It is pumped with a diode-pumped passively mode-locked 10-GHz Nd:YVO(4) laser. Because of its high repetition rate and its potential for ultrabroad tunability, this kind of system is useful for telecom applications. It should be scalable to 40 GHz and higher as required for future telecom networks.

Highly functionalized dimeric tetraethynylethenes and expanded radialenes: strong evidence for macrocyclic cross-conjugation

A selection of dimeric tetraethynylethenes (TEEs) and perethynylated expanded radialenes, containing different donor/acceptor substitution patterns, have been prepared and fully characterized. The first X-ray crystal structure of an expanded [6]radialene, with twelve peripheral 3,5-di(tert-butyl)phenyl substituents, is presented. This macrocycle, the all-carbon core of which is isomeric with fullerene C60, adopts a non-planar, "chair-like" conformation. Also a TEE dimer, carrying N,N-dimethylaniline donor substituents, has been subjected to an X-ray crystallographic analysis. The electronic properties were studied by UV/Vis spectroscopy and electrochemistry, providing fundamental insight into mechanisms of pi-electron delocalization in the acyclic and macrocyclic chromophores. Donor or donor-acceptor-substituted dimeric TEE derivatives show very strong absorptions extending over the entire UV/Vis region; their longest wavelength absorption bands have high charge-transfer character. Macrocyclic cross-conjugation in the expanded radialenes becomes increasingly efficient with increasing donor-acceptor polarization. A dual, strongly solvent-polarity-dependent fluorescence was observed for a tetrakis(N,N-dimethylaniline)-substituted dimeric TEE; this interesting emission behavior is explained by the twisted intramolecular charge-transfer (TICT) state model. Donor-substituted expanded radialenes display huge resonance-enhanced third-order nonlinear optical coefficients.

Cesium-133: a potential reporter of the hepatic uptake of contrast agents

NMR spectroscopy of intracellularly located (133)Cs has been used to monitor the uptake of Gd-EOB-DTPA by the isolated rat liver. As shown by (31)P spectroscopy, accumulation of (133)Cs ions in hepatocytes does not produce detectable effects on the metabolism. The hepatic internalization of Gd-EOB-DTPA was followed by the paramagnetic relaxation enhancement of the intracellular (133)Cs ions, and confirmed by parallel quantitations of Gd and Cs run by inductively coupled plasma (ICP) analysis of liver samples and aliquots of perfusate. The relaxation data significantly underestimate the Gd content, suggesting a potential compartmentation of Cs(+) and/or the contrast agent. Magn Reson Med 45:711-715, 2001.

Structural changes of cytochrome c(552) from Thermus thermophilus adsorbed on anionic and hydrophobic surfaces probed by FTIR and 2D-FTIR spectroscopy

The structural changes of cytochrome c(552) bound to anionic and hydrophobic clay surfaces have been investigated by Fourier transform infrared spectroscopy. Binding to the anionic surface of montmorillonite is controlled by electrostatic interactions since addition of electrolyte (0.5 mol L(-1) KCl) causes desorption of more than 2/3 of the protein molecules. Electrostatic binding occurs through the back side of the protein (i.e., remote from the heme site) and is associated only with subtle changes of the secondary structure. In contrast, adsorption to the hydrophobic surface of talc leads to a decrease in alpha-helical structure by ca. 5% and an increase in beta-sheet structure by ca. 6%. These structural changes are attributed to a hydrophobic region on the front surface of cytochrome c(552) close to the partially exposed heme edge. This part on the protein surface is identified as the interaction domain for talc and most likely also serves for binding to the natural reaction partner, a ba(3)-oxidase. Fourier transform infrared spectra of cytochrome c(552) and the clay-cytochrome c(552) complexes have been measured as a function of time following dissolution and suspension in deuterated buffer, respectively. A two-dimensional correlation analysis was applied to these spectra to investigate the dynamics of the structural changes in the protein. For both complexes, adsorption and subsequent unfolding processes in the binding domains are faster than the time resolution of the spectroscopic experiments. Thus, the processes that could be monitored are refolding of peptide segments and side chain rearrangements following the adsorption-induced perturbation of the protein structure and the solvation of the adsorbed protein. In each case, side chain alterations of solvent-exposed tyrosine, aspartate, and glutamate residues were observed. For the cytochrome c(552)-talc complex, these changes are followed by a slow refolding of the peptide chain in the binding domain and, subsequently, a further H/D exchange of amide group protons.

Self-aligned extended-cavity diode laser stabilized by the Zeeman effect on the cesium D2 line

An extended-cavity diode laser at 852 nm has been built especially for the purpose of cooling and probing cesium atoms. It is a compact, self-aligned, and continuously tunable laser source having a 100-kHz linewidth and 60-mW output power. The electronic control of the laser frequency by the piezodriven external reflector covers a 4.5-kHz bandwidth, allowing full compensation of acoustic frequency noise without any adverse effect on the laser intensity noise. We locked this laser to Doppler-free resonances on the cesium D(2) line by using the Zeeman modulation technique, resulting in the frequency and the intensity of the laser beam being unmodulated. We also tuned the locked laser frequency over a span of 120 MHz by using the dc Zeeman effect to shift the F = 4-F' = 5 reference transition.

The development of a French version of a questionnaire on the quality of life in cancerology (Functional Living Index-Cancer: FLIC)

The quality of life has become an indispensable element in the evaluation of treatments, especially as clinical trials are generally conducted in more than one country. In cancerology, numerous questionnaires have been developed and validated, but most of them are in English. This article presents the stages of translation and validation of the French version of the FLIC (Functional Living Index-Cancer). It applies to a sample of 200 patients, 47% of whom have breast cancer. The acceptability of this questionnaire is good (92.2%). The main psychometric criteria were verified. The Cronbach alpha coefficient, equal to 0.90, shows good reliability. A factor analysis was conducted to examine construct validity; it revealed a 5-factor solution accounting for 62% of the variance. These 5 factors are associated with specific domains; physical, psychological and social functioning, current well-being and disease symptoms. The global scores of the FLIC correlate significantly with those of the different scales of the EORTC QLQ-C30. Moreover, clinical relevance is ensured by its correlation with certain clinical variables (WHO index, location of tumour). The French version of the FLIC can be used to measure the quality of life of patients afflicted with cancer, but further studies are necessary to confirm its reliability.

Effectiveness of cold cap in the prevention of docetaxel-induced alopecia

Docetaxel is a new taxoid antineoplastic agent with clinical efficacy especially in breast cancer. One of the most distressing side-effects induced by docetaxel is alopecia. We studied the prevention of alopecia by using a cold cap in 98 patients receiving 100 mg/m2 docetaxel by 1 h i.v. infusion every 3 weeks. One patient was lost to follow-up. 83 patients (86%) were evaluated as a success to the cold cap, as they presented WHO grade alopecia < or = 2 and no need to wear a wig. 14 patients (14%) had to wear a wig; among them; 7 patients withdrew before the evaluation at three cycles. The cold cap is a very effective technique with minimal side-effects for docetaxel-treated patients.

Quality of life as an outcome in breast cancer. Clinical application

In clinical trials of anticancer agents, the assessment of objective effects has historically been the primary end-point. However, because of the limited impact of these agents on survival, the study of quality of life (QOL) has become increasingly important. QOL evaluation is difficult and the approaches of physicians and reimbursors of healthcare are quite different. In addition, QOL is not a simple concept and several different methods have been used to evaluate it. These methods can be divided into the following 2 groups: experimental methods [the best known is the quality-adjusted life-year (QALY), which utilise some kind of experimentation; and observational methods, which use questionnaires and are often multifactorial. Some of these questionnaires are used for patients with all types of pathologies, while others are cancer-specific; all questionnaires must be validated. We conducted 3 QOL studies in patients with breast cancer using the Functional Living Index-Cancer (FLIC) questionnaire. In the first, a French translation of the FLIC questionnaire was validated. The FLIC and Functional Living Index-Emesis (FLIE) questionnaires were used to assess QOL in a second study comparing 2 different antiemetics for the control of nausea and vomiting. Finally, QOL was evaluated in patients with breast cancer during adjuvant chemotherapy. Several other studies employing different questionnaires in patients with breast cancer have been published. Clinical applications for QOL evaluation in oncology may be the prognostic implications of QOL, evaluation of toxicity and duration of treatment, and evaluation of utility and QOL. However, although assessment of QOL is important for both physicians and funders, there is no gold standard method available, and the results of QOL studies have to be interpreted cautiously.

Pulmonary ventilation, mechanics, gas exchange and haemodynamics in calves following intratracheal inoculation of Pasteurella haemolytica

A Pasteurella haemolytica A1 broth was injected intratracheally in eight calves and measurements of pulmonary function values (PFV) were made once before and hourly post inoculation (p.i.). Changes in PFVs, included increased respiratory rate and minute ventilation (up to 158% of baseline 2 h p.i.) and decreased tidal volume and lung dynamic compliance (up to 33% of baseline 3 h p.i.). Total pulmonary resistance was not affected. At and after 3 h p.i. there was a progressive impairement of gas exchange, as judged from arterial O2 tension which decreased up to 65% of baseline. In contrast, arterial CO2 tension was not affected. Pulmonary hypertension was observed during the 3 last h of the study and was attributable to an increased pulmonary vascular resistance. Severe neutropenia was observed at 3 h p.i. and post-mortem histological findings were consistent with an acute fibrinohemorragic bronchopneumonia. In conclusion, P. haemolytica airway challenge unequiovocally resulted in acute pneumonia, providing a reproducible pathophysiological model for investigations regarding new therapeutic strategies.

[Immunotherapy of malignant melanoma. New prospects]

Malignant melanoma is an immunogenic tumor which can induce host humoral and cellular responses, and is a good model for development of anti-cancer immunotherapy. During the last decade systemically-administrated interferon and interleukin-2 have been used. Advances in immunology and molecular biology could allow a more specific and active immunotherapy. Perspectives include chemo-immunotherapy, monoclonal antibodies alone or in combination with cytotoxic agents, adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL), gene therapy designed to increase tumor immunogenicity, and active immunotherapy with vaccines.

Stimulation of cortisol production through angiotensin AT2 receptors in bovine fasciculata cells

Bovine fasciculata cells in culture (BAC) express both AT1 and AT2 angiotensin receptors. The role and signaling pathways of this latter receptor are still the subject of debate. We found that in BAC stimulation of cortisol (F) production by angiotensin II (A II) is accounted for by both receptor subtypes. We have investigated the potential AT2 signalling pathways involved in this response. As previously described in other cells, we found this receptor to mediate inhibition of ANP stimulated cGMP production through a phosphodiesterase independent pathway. This phenomenon does however not appear to be involved in cortisol production as this response was not affected by the addition of 8-Br-cGMP or ANP. It was however abolished after down-regulation of PKC by phorbol esters, but not by Gi inhibition with pertussis toxin. Moreover and as opposed to the AT1 mediated response, AT2 receptor stimulation potentiated K+ induced F production. In conclusion, these observations suggest that the AT2 pathway which mediates F production requires intact PKC and might involve a Gi independent stimulation of Ca++ or K+ channels.

[Insufficient efficacy of the use of a single 8 mg tablet of ondansetron in the prevention of nausea and vomiting induced by FEC chemotherapy]

This study was performed in a group of 89 patients treated for breast carcinoma with a FEC regimen (5-fluorouracil, epirubicin, cyclophosphamide). The aim was to evaluate the antiemetic efficacy of one 8 mg tablet ondansetron (OND), and in case of failure, to measure the recovering level by the administration of 8 mg i.v. OND. One tablet of OND was given before the first course. A complete or major control of emetic episodes (EE) (0-2 EE) over the 24 first hours was obtained in 55 patients (62%). A complete or major control of nausea (absent or mild) was obtained in 46 patients (52%). A success, defined as a complete or major control for EE and nausea during the first 5 days, was obtained in 36 patients (40%). These 36 patients were treated again with 8 mg oral OND at the second course, with a success level of 61% (22/36). Among the 53 patients unresponsive to the oral OND, 38 were treated by 8 mg i.v. OND at the second course. A complete or major control for EE and for nausea over the first 24 hours was obtained respectively in 11 patients (29%), and 11 patients (29%). No success was obtained. The 15 remaining patients, who had a very bad tolerance at the first course were excluded from the study and treated by OND-methylprednisolon, with only one success obtained. This study shows that the exclusive use of one 8 tablet OND is not sufficient in prevention of emesis induced by a FEC regimen, and that failures are only partially recovered by the i.v. route.

Effect of magnesium complexation by fluoroquinolones on their antibacterial properties

By using infrared and 19F nuclear magnetic resonance spectroscopies, we localized the binding site and measured the affinity of magnesium for six fluoroquinolones. It was proven that magnesium is situated between the ketone and the carboxylate groups. We determined the binding constants for the 1:1 Mg(2+)-drug complex in solution. Sparfloxacin and pefloxacin, with affinity constants (Ka) of (10.1 +/- 0.6) x 10(2) M-1 and (21 +/- 1) x 10(2) M-1, respectively, were the least and the most bound, respectively. The trend of the affinities of the assayed fluoroquinolones for magnesium was correlated with their antimicrobial activities against four bacteria and with their accumulation by these bacteria. The reference strain, Escherichia coli KL16, and two resistant mutants, NalA (gyrase mutation) and NalB (uptake defect), plus Staphylococcus aureus 209P were used. It appeared that, in every case, an impairment of accumulation is responsible for the increase in the MICs observed upon the addition of magnesium.

[Antiemetic treatment and chemotherapy: general review]

Chemotherapy-induced nausea and emesis are frequent and patients fearful. Emesis caused by cytotoxic agents can be related to their effects on central chemoreceptor or on the gut chemoreceptor by serotonin. 5HT3 receptor antagonists produce a major improvement in the control of cisplatin induced-emesis (70 to 80% of patients). The 5HT3-antagonist efficacy is significantly better than metoclopramide alone, or antimemetic combinations in highly emetogenic chemotherapy regimens but less good in moderately emetogenic chemotherapy. Studies with 5HT3 receptor antagonist plus corticosteroids show advantage over 5HT3 antagonist alone. Comparison studies between the different setrons didn't show any significant difference. Anticipary emesis are treated with anxiolytic drugs. The prevention of delayed emesis, not yet well controlled by 5HT3 antagonist, is a great therapeutic deal. Finally, some therapeutic problems are not resolved: minimal dose, use of oral route, efficacy in fractionated chemotherapy, treatment after loss of efficacy of 5HT3 antagonist.