An overview of the literature on emerging pollutants: Chlorinated derivatives of Bisphenol A (ClxBPA)

CONTEXT

Bisphenol A (BPA) is a ubiquitous contaminant with endocrine-disrupting effects in mammals. During chlorination treatment of drinking water, aqueous BPA can react with chlorine to form chlorinated derivatives of BPA (mono, di, tri and tetra-chlorinated derivatives) or Cl_xBPA.

OBJECTIVE

The aim of this study is to summarize and present the state of knowledge on human toxicological risk assessment of Cl_xBPA.

MATERIALS AND METHODS

A search on Cl_xBPA in the PubMed database was performed based on studies published between 2002 and 2021. Forty-nine studies on chlorinated derivatives of BPA were found. Available information on their sources and levels of exposure, their effects, their possible mechanisms of action and their toxicokinetics data was extracted and presented.

RESULTS

Cl_xBPA have been essentially detected in environmental aqueous media. There is evidence in toxicological and epidemiological studies that Cl_xBPA also have endocrine-disrupting capabilities. These emerging pollutants have been found in human urine, serum, breast milk, adipose and placental tissue and can constitute a risk to human health. However, in vitro and in vivo toxicokinetic data on Cl_xBPA are scarce and do not allow characterization of the disposition kinetics of these compounds.

CONCLUSION

More research to assess their health risks, specifically in vulnerable populations, is needed. Some water chlorination processes are particularly hazardous, and it is important to evaluate their chlorination by-products from a public health perspective.

A trend of dropping anti-SARS-CoV-2 plaque reduction neutralization test titers over time in Canadian convalescent plasma donors

BACKGROUND

Convalescent plasma products are a potential passive immunotherapy for Coronavirus disease 2019 (COVID-19) disease. Various approaches have been utilized to determine the concentration of Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-neutralizing antibodies in plasma products. The Canadian Blood Services used Plaque Reduction Neutralization Test 50 (PRNT₅₀₎ -generated values to qualify convalescent plasma donations supporting clinical trials in Canada. This manuscript describes changes in PRNT₅₀ titers of repeat male plasma donations collected approximately 1-4 months after onset of COVID-19 signs and symptoms in donors.

STUDY DESIGN AND METHODS

Men were eligible to donate if they: met standard criteria, were < 67 years of age, reported a previous SARS-CoV-2-positive nucleic acid test, and recovered and were symptom free for at least 28 days prior to donation. Repeat donation analysis required at least one original and one repeat donation where a PRNT₅₀ was performed.

RESULTS

From April 29, 2020 to July 25, 2020, 156 donors donated once, with 78 (50%) of the donated plasma having PRNT₅₀ titers of ≥1:160. Thirty-seven (23.7%) of the donated plasma had a titer of 1:40 or 1:80 (individuals donating this plasma were asked to donate a second time only). A total of 30 donors (19.2%) had repeat donations. Of the repeat donors, 15 (50%) had at least an eightfold change from peak to trough PRNT₅₀ titers within greater than 90 days after onset of COVID-19 symptoms.

CONCLUSIONS

Blood operators cannot infer that SARS-CoV-2 PRNT₅₀ will remain high in repeat plasma donors 3-4 months after onset of COVID-19 symptoms.

[Neonates exposure to parabens through medicines administered to inpatients]

OBJECTIVES

The objective of this study was to quantify parabens intake due to drug administration in neonates during hospitalization following their birth.

METHOD

A monocentric prospective study was performed into a neonatalogy unit to collect all drug prescriptions. An exhaustive list of parabens containing medicines commercialized in France was completed from Theriaque® database. This list was combined with drug prescription to establish an exposure profile to parabens. For each paraben containing medicines, a HPLC-UV assay was performed to determine the average daily intake of paraben received by hospitalized neonates.

RESULTS

More than 300 medicines commercialized in France contain at least one paraben. A combination of methylparaben and propylparaben was found in most cases. All hospitalized neonates (n=22) were exposed at least once to methylparaben and propylparaben through medicines while 50 % were exposed to ethylparaben. The average daily intake was higher in term newborns (572,0±249,0 versus 414,6±294,1μg/kg/j for methylparaben) but frequency was higher in prematures (65,0 versus 78,6% for methylparaben) as well as cumutives doses (1421,5±758,8 versus 8618,7±7922,3). These doses are lower than toxicological reference values but these latter do not take into account endocrine disrupting effects of these compounds.

CONCLUSIONS

These results highlight medicines as a high source of exposure to parabens in hospitalized neonates. It should encourage pharmaceutical companies and health professionnal to prioritize therapeutic cares without parabens.

Epidemiological Characteristics and Laboratory Findings of Zika Virus Cases in New York City, January 1, 2016-June 30, 2017

BACKGROUND

An outbreak of Zika virus (ZIKV) began in May 2015 in Brazil and rapidly spread throughout the Americas; New York City (NYC) has a diverse population with ∼1.8 million residents who were born in ZIKV-affected areas. Before July 24, 2017, the Centers for Disease Control and Prevention (CDC) ZIKV testing recommendations included nucleic acid amplification-based tests for serum and urine specimens collected ≤14 days of illness onset or last potential exposure, and ZIKV immunoglobulin M (IgM) assay when ZIKV RNA is not detected or for specimens collected within 2-12 weeks of illness onset or last potential exposure, followed by a plaque reduction neutralization test (PRNT). However, the New York public health laboratories and commercial laboratories tested specimens collected beyond these time frames.

METHODS

We analyzed 1080 noncongenital ZIKV cases in NYC residents who met the Council for State and Territorial Epidemiologist's ZIKV case definitions.

RESULTS

Among cases, 98% were travel associated, 1% were sexually transmitted, and 1% had unknown exposures; 412 (38%) cases were pregnant women. Of 672 patients with ZIKV RNA detected in serum or urine specimens, 48 (7%) tested positive >14 days after either symptom onset or last potential exposure date (range 15-99 days). Of 390 patients diagnosed based on serology alone (i.e., not tested or not detectable for ZIKV RNA), 60 (15%) had a positive ZIKV IgM and PRNT >12 weeks after symptom onset or last potential exposure date (range 85-273 days).

CONCLUSION

Our findings correspond with CDC's updated guidance to test symptomatic pregnant women up to 12 weeks past onset of symptoms. ZIKV IgM antibody testing may also be warranted for pregnant women regardless of symptoms if their exposure occurred during their pregnancy or periconception period. Providers should understand the scope of diagnostic testing and its limitations to appropriately counsel patients, especially pregnant women.

Does area deprivation modify the association between exposure to a nitrate and low-dose atrazine metabolite mixture in drinking water and small for gestational age? A historic cohort study

Birth weight may be influenced by environmental and socio-economic factors that could interact. The main objective of our research was to investigate whether area deprivation may modify the association between drinking water exposure to a mixture of atrazine metabolites and nitrates during the second trimester of pregnancy and prevalence of small for gestational age (SGA) neonates. We conducted a historic cohort study in Deux-Sèvres, France between 2005 and 2010, using birth records, population census and regularly performed drinking water withdrawals at community water systems. Exposure to an atrazine metabolite/nitrate mixture in drinking water was divided into six classes according to the presence or absence of atrazine metabolites and to the terciles of nitrate concentrations in each trimester of pregnancy. We used a logistic regression to model the association between SGA and mixture exposure at the second trimester while taking into account the area deprivation measured by the Townsend index as an effect modifier and controlling for the usual confounders. We included 10,784 woman-neonate couples. The risk of SGA when exposed to second tercile of nitrate without atrazine metabolites was significantly greater in women living in less deprived areas (OR = 2.99; 95 % CI (1.14, 7.89)), whereas it was not significant in moderately and more deprived areas. One of the arguments used to explain this result is the presence of competing risk factors in poorer districts.

Response inhibition and ADHD traits: correlates and heritability in a community sample

Endophenotypes or intermediate phenotypes are of great interest in neuropsychiatric genetics because of their potential for facilitating gene discovery. We evaluated response inhibition, latency and variability measures derived from the stop task as endophenotypes of ADHD by testing whether they were related to ADHD traits in the general population, heritable and shared genetic risk with ADHD traits. Participants were 16,099 children and adolescents, ages 6 to 18 years who visited a local science center. We measured ADHD traits using the Strengths and Weaknesses of ADHD-symptoms and Normal-Behavior (SWAN) rating scale and performance on the stop signal task (SST)-response inhibition (SSRT), response latency (GoRT), and response variability (GoRTSD). Regression analysis was used to assess the relationship of cognitive measures and ADHD traits while controlling for family, age, sex, ethnicity, socioeconomic status and treatment status. Heritability of ADHD and cognitive traits was estimated using SOLAR in 7,483 siblings from 3,507 families that included multiple siblings. Bivariate relationships between pairs of variables were examined. Individuals with greater ADHD trait scores had worse response inhibition, slower response latency, and greater variability. Younger participants and girls had inferior performance although the gender effects were minimal and evident in youngest participants. Inhibition, latency, variability, total ADHD traits, inattention and hyperactivity-impulsivity scores were significantly heritable. ADHD traits and inhibition, but not latency or variability were coheritable. In the largest study in the general population, we found support for the validity of response inhibition as an endophenotype of ADHD.

Drinking-water exposure to a mixture of nitrate and low-dose atrazine metabolites and small-for-gestational age (SGA) babies: a historic cohort study

BACKGROUND

Groundwater, surface water and drinking water are contaminated by nitrates and atrazine, an herbicide. They are present as a mixture in drinking water and with their endocrine-disrupting activity, they may alter fetal growth.

OBJECTIVES

To study an association between drinking-water atrazine metabolites/nitrate mixture exposure and small-for-gestational-age(SGA).

METHODS

A historic cohort study based on birth records and drinking-water nitrate and pesticide measurements in Deux-Sèvres (France) between 2005 and 2009 was carried out. Exposure to drinking-water atrazine metabolites/nitrate mixture was divided into 6 classes according to the presence or absence of atrazine metabolites and to terciles of nitrate concentrations in each trimester of pregnancy. Regression analysis of SGA by mixture exposure at second trimester was subsequently conducted.

RESULTS

We included 11,446 woman-neonate couples of whom 37.0% were exposed to pesticides, while 99.9% of the women were exposed to nitrates. Average nitrate concentration was from 0 to 63.30 mg/L. In the second trimester of pregnancy, the risk of SGA was different with mixture exposure when drinking-water atrazine metabolites, mainly 2 hydroxyatrazine and desethylatrazine, were present and nitrate dose exposure increased: compared to single first tercile of nitrate concentration exposure, single second tercile exposure OR was 1.74 CI 95% [1.10; 2.75] and atrazine metabolites presence in the third tercile of nitrate concentration exposure OR was 0.87 CI 95% [0.45;1.67].

CONCLUSIONS

It is possible that the association found at the second trimester of exposure with regard to birth weight may likewise be observed before birth, with regard to the estimated fetal weight, and that it might change in the event that the atrazine metabolites dose were higher or the nitrate dose lower. It would appear necessary to further explore the variability of effects.

Acute gut GVHD in children: does skin involvement matter?

Gut GVHD (G-GVHD) is frequently the most severe and difficult to treat compared with skin GVHD. It is unknown if skin involvement with G-GVHD has prognostic significance. To compare the prognosis of acute isolated G-GVHD vs acute gut and skin GVHD (GS-GVHD) in children following allo-SCT. Allo-SCT recipients from Jan 2000-Dec 2009 were included and patients who underwent endoscopy and gut biopsy for G-GVHD were identified. Four hundred and fifty children (0-18 years) underwent allo-SCT during the study period. Seventy-nine (17.5%) patients underwent endoscopy and biopsy. At least stage II was required for skin involvement. Forty nine patients had G-GVHD and 30 had combined, GS-GVHD. The majority of patients received CsA and MTX for GVHD prophylaxis. Sixty-seven percent of patients with GS-GVHD had grade III-IV while only 31% had grade III-IV in the G-GVHD group. Median follow-up was 6.3 years (range 3.6-11.9 years). Relapse rate was similar in both the groups. However, children with G-GVHD had a significantly higher risk of dying from GVHD related complications (37% vs 16%) resulting in superior survival for those with skin involvement (79% vs 49% P=0.02). Extension of G-GVHD to the skin may suggest a better outcome.

West Nile virus infection of birds, Mexico

Birds of 2 of 3 passerine species died after experimental infection with 2 strains from Mexico.

West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006–2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths.

A comparison of the outcomes of children with acute myelogenous leukemia in either first or second complete remission (CR1 vs CR2) following allogeneic hematopoietic stem cell transplantation at a single transplant center

We reviewed 70 consecutive children with AML who received hematopoietic stem cell transplantation (HSCT) in our institution between 1994 and 2005. Forty-seven children were transplanted in CR1 and 23 were transplanted in CR2. BU/CY was the most common pretransplant conditioning regimen for CR1 patients and a TBI-based conditioning regimen was the most common regimen for CR2 patients. Most patients transplanted in CR1 (81%) received related donor HSCT, whereas most of the CR2 patients (74%) received unrelated donor HSCT. Expectedly, there was a significant increase in acute GVHD incidence in CR2 patients (40 vs 25% for grades I-II and 30 vs 10% for grades III-IV; P=0.02) and a significant increase in transplant-related mortality (38 vs 11%; P=0.01). Although the difference between 3-year EFS for CR1 and CR2 was not statistically significant, there was a significantly superior 3-year overall survival for CR1 patients (74 vs 51%; P=0.05). Children with relapsed AML who achieve and maintain remission until HSCT, have a reasonable survival, but the outcome of children receiving HSCT in CR1 remains superior.

Coupling lattice Boltzmann and molecular dynamics models for dense fluids

We propose a hybrid model, coupling lattice Boltzmann (LB) and molecular dynamics (MD) models, for the simulation of dense fluids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The MD and LB formulations communicate via the exchange of velocities and velocity gradients at the interface. We validate the present LB-MD model in simulations of two- and three-dimensional flows of liquid argon past and through a carbon nanotube. Comparisons with existing hybrid algorithms and with reference MD solutions demonstrate the validity of the present approach.

[Imogam rage prescription assessment in the rabies prophylaxis center of Poitiers]

OBJECTIVES

Imogam rage (IgR) prescriptions were assessed in the rabies prophylaxis centre of Poitiers (France).

MATERIAL AND METHODS

All medical records closed between January 1 and June 1, 2005 were retrospectively analyzed. An infectious disease specialist examined the pertinence of IgR prescription according to WHO references adapted to the epidemiological situation by the Pasteur Institute French rabies center. The indicator used was the proportion of patients treated by IgR among all patients treated by vaccination or vaccination with IgR.

RESULTS

During the study period, 69 medical records have bewereen analyzed: 48 (70%) patients were treated including 22 (46%) with IgR. Imogam rage indication was not appropriate for 21 (95%) patients (one contact with a rodent, 8 low gravity contact, 12 contacts with a French animal) that is to say 86 IgR vials. The direct cost was 8,032 euros.

CONCLUSION

This assessment permitted to underline an overprescription of IgR, to adapt guidelines to the local situation, and to improve care quality by adaptating medical record files, improving the prescription decisional tree and the local guidelines, and improving the training of interns.

Na+ channel-mediated Ca2+ entry leads to glutamate secretion in mouse neocortical preplate

Before synaptogenesis, early excitability implicating voltage-dependent and transmitter-activated channels is known to be crucial for neuronal development. We previously showed that preplate (PP) neurons of the mouse neocortex express functional Na(+) channels as early as embryonic day 12. In this study, we investigated the role of these Na(+) channels in signaling during early development. In the neocortex of embryonic-day-13 mice, activation of Na(+) channels with veratridine induced a large Ca(2+) response throughout the neocortex, even in cell populations that lack the Na(+) channel. This Na(+)-dependent Ca(2+) activity requires external Ca(2+) and is completely blocked by inhibitors of Na(+)/Ca(2+) exchangers. Moreover, veratridine-induced Ca(2+) increase coincides with a burst of exocytosis in the PP. In parallel, we show that Na(+) channel stimulation enhances glutamate secretion in the neocortical wall. Released glutamate triggers further Ca(2+) response in PP and ventricular zone, as indicated by the decreased response to veratridine in the presence of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor and NMDA-receptor inhibitors. Therefore, the combined activation of the Na(+) channel and the Na(+)/Ca(2+) exchanger triggers Ca(2+) signaling in the PP neurons, leading to glutamate secretion, which amplifies the signal and serves as an autocrine/paracrine transmitter before functional synapses are formed in the neocortex. Membrane depolarization induced by glycine receptors activation could be one physiological activator of this Na(+) channel-dependent pathway.

Rheology of cholesteric blue phases

Cholesteric blue phases are a spectacular example of disclination line networks. Here we numerically investigate their response to an imposed Poiseuille flow. We show that shear forces bend and twist and can unzip the disclination lines. Under gentle forcing the network opposes the flow and the apparent viscosity is large. With increased forcing we find strong shear thinning corresponding to the disruption of the network. As the viscosity starts to drop, the imposed flow sets the network into motion. Disclinations break up and re-form with their neighbors along the flow.

Modeling droplets on superhydrophobic surfaces: equilibrium states and transitions

We present a lattice Boltzmann solution of the equations of motion describing the spreading of droplets on topologically patterned substrates. We apply it to model superhydrophobic behavior on surfaces covered by an array of micrometer-scale posts. We find that the patterning results in a substantial increase in contact angle, from 110 degrees to 156 degrees. The dynamics of the transition from drops suspended on top of the posts to drops collapsed in the grooves is described.

Numerical calculations of the phase diagram of cubic blue phases in cholesteric liquid crystals

We study the static properties of cubic blue phases by numerically minimizing the three-dimensional, Landau-de Gennes free energy for a cholesteric liquid crystal close to the isotropic-cholesteric phase transition. Thus we are able to refine the powerful but approximate, semianalytic frameworks that have been used previously. We obtain the equilibrium phase diagram and discuss it in relation to previous results. We find that the value of the chirality above which blue phases appear is shifted by 20% (toward experimentally more accessible regions) with respect to previous estimates. We also find that the region of stability of the O5 structure-which has not been observed experimentally-shrinks, while that of blue phase I ( O-8 ) increases thus giving the correct order of appearance of blue phases at small chirality. We also study the approach to equilibrium starting from the infinite chirality solutions and we find that in some cases the disclination network has to assemble during the equilibration. In these situations disclinations are formed via the merging of isolated aligned defects.

Pharmacokinetic-pharmacodynamic modelling of the electroencephalogram effect of imipenem in rats with experimental hypovolaemia or endotoxaemia

OBJECTIVES

The epileptogenic activity of imipenem in rats with experimentally induced hypovolaemia or endotoxaemia was investigated by pharmacokinetic-pharmacodynamic modelling of the electroencephalogram effect.

METHODS

Hypovolaemia was induced by removal of 30% of the blood volume and endotoxaemia by intravenous lipopolysaccharide injection.

RESULTS

Imipenem clearance and volume of distribution values of 16.4+/-1.1 mL/min per kg and 357+/-49 mL/kg (mean+/-S.E.M.) in healthy rats (n=5), were significantly reduced in hypovolaemic (n=6) and endotoxaemic (n=6) animals. A dose reduction from 250 mg/kg to 120 mg/kg was necessary in endotoxaemic rats. The pharmacokinetic-pharmacodynamic model with an effect compartment previously developed in healthy rats described the data adequately and pharmacodynamic parameters in hypovolaemic and endotoxaemic rats were not significantly different from corresponding values estimated in the control group.

CONCLUSION

Hypovolaemia and endotoxaemia only had an effect on imipenem pharmacokinetics.

Pharmacokinetic-pharmacodynamic modeling of electroencephalogram effect of imipenem in rats with acute renal failure

The epileptogenic activity of imipenem was investigated in rats with experimental renal failure induced by uranyl nitrate injection by using electroencephalogram (EEG) recording and a pharmacokinetic-pharmacodynamic model including an effect compartment. Results previously obtained with healthy rats were used to estimate the dose of imipenem required to induce an observable but nonlethal EEG effect on the assumption that only the pharmacokinetic parameters of the model would be affected by renal failure. Good agreement was observed between the predicted and observed effects.

Pharmacokinetic-pharmacodynamic modeling of the electroencephalogram effect of imipenem in healthy rats

A pharmacokinetic-pharmacodynamic (PK-PD) modeling approach was developed to investigate the epileptogenic activity of imipenem in rats. Initially, animals received an intravenous infusion of imipenem at a rate of 2.65 mg min(-1) for 30 min. Blood samples were collected for drug assay, and an electroencephalogram (EEG) was recorded during infusion and postinfusion. A dramatic delay was observed between concentrations of imipenem in serum and the EEG effect; this effect was accompanied by tremors and partial seizures. Indirect-effect models failed to describe these data, which were successfully fitted using an effect compartment model. The relationship between effect and concentration at the effect site was best described by a spline function. The elimination rate constant from the effect compartment was severalfold lower than that from the central compartment. The robustness of the model was then confirmed after administering the imipenem dose over 60 and 90 min. In conclusion, the successful PK-PD modeling of the imipenem EEG effect in rats constitutes a major improvement for better prediction of the epileptogenic risk associated with this antibiotic.

Toward a characterization of the connecting module of complex I

Complex I [NADH-ubiquinone oxidoreductase (complex I, EC 1.6.5.3)] couples electron transfer between NADH and ubiquinone to proton transport across the bacterial cytoplasmic membrane and the mitochondrial inner membrane. This sophisticated enzyme consists of three specialized modules: (1) a hydrophilic NADH-oxidizing module that constitutes the input machinery of the enzyme; (2) a hydrophobic module that anchors the enzyme in the membrane and must take part in proton transport; and (3) a connecting domain that links the two previous modules. Using the complex I of Rhodobacter capsulatus, we developed a genetic study of the structure and function of the connecting module. In the present review, we put together the salient results of these studies, with recent reports of the literature, to try and elucidate the structure of the connecting module and its potential role in the coupling process between electron and proton flux within complex I. From this overview, we conclude that the NUOB-NUOD dimer of the connecting module and a hydrophobic subunit such as NUOH must share a quinone-reduction site. The function of this site in the mechanism of complex I is discussed.

Evidence for a quinone binding site close to the interface between NUOD and NUOB subunits of Complex I

Piericidin, rotenone and pyridaben are specific inhibitors of the NADH-ubiquinone oxidoreductase (Complex I) that bind to its ubiquinone binding site(s). Using site directed mutagenesis, we demonstrate that residues G409, D412, R413 and V407 of the C-terminus of Complex I NUOD subunit are directly involved in the binding of these inhibitors. We propose that the corresponding inhibitor/quinone binding site would be located close to NUOD-NUOB interface.

Is ferromagnetism an intrinsic property of the CuII/GdIII couple? 2. Structures and magnetic properties of novel trinuclear complexes with mu-phenolato-mu-oximato (Cu-Ln-Cu) cores (Ln = La, Ce, Gd)

The present paper is devoted to the study of original trinuclear (CuII, LnIII, CuII) complexes (Ln = La, Ce, Gd). They derive from the polydentate ligands H2Li (i = 1, 3, 4) represented in Figure 1. The crystal and molecular structures of two complexes have been determined at room temperature. The (Cu, Gd, Cu) complex of H2L1 1Gd and the (Cu, Ce, Cu) complex of H2L3 3Ce crystallize in the triclinic space group P1 (no. 2) with the following cell parameters: a = 14.005(2) A, b = 14.7581(13) A, c = 11.3549(13) A, alpha = 96.273(9) degrees, beta = 97.648(11) degrees, gamma = 72.946(9) degrees, V = 2217.7(4) A3, and Z = 2 for 1Gd and a = 11.226(2) A, b = 16.927(3) A, c = 11.010(2) A, alpha = 108.67(2) degrees, beta = 110.48(1) degrees, gamma = 92.35(2) degrees, V = 1828.7(5) A3, and Z = 2 for 3Ce. Regarding possible supports for magnetic interactions, it may be noted that, in both complexes, each of the main bridging pathways between the equatorial positions of a copper(II) ion and the related lanthanide ion is double and not symmetrical. It involves a phenolato oxygen atom and an oximato nitrogen-oxygen pair of atoms. The resulting Cu(O,N-O)Gd networks are not planar, but 3Ce displays much larger deviations than does 1Gd. Determination of the thermal dependence of chi M (molar susceptibility) and the field variations of M (magnetization) show that in 3Gd and 4Gd the Cu-Gd interactions are antiferromagnetic while more "usual" ferromagnetic interactions are observed for 1Gd. The possibility of a relationship between structural and magnetic parameters is considered.

A comparison of inhaled fluticasone and oral prednisone for children with severe acute asthma

BACKGROUND

Inhaled corticosteroids are effective in the treatment of children with asthma. It is uncertain how inhaled corticosteroids compare with oral corticosteroids in the management of severe acute disease.

METHODS

We performed a double-blind, randomized trial involving 100 children five years of age or older who had severe acute asthma (indicated by a forced expiratory volume in one second [FEV1] that was less than 60 percent of the predicted value) and in whom the results could be evaluated. All were treated with an aggressive bronchodilator regimen and received one dose of either 2 mg of inhaled fluticasone through a metered-dose inhaler with a spacer or 2 mg of oral prednisone per kilogram of body weight. They were assessed hourly for up to four hours.

RESULTS

The mean (+/-SD) base-line FEV1 as a percentage of the predicted value was 46.3+/-12.5 in the fluticasone group (51 subjects) and 43.9+/-9.9 in the prednisone group (49 subjects). The FEV1 increased by a mean of 9.4+/-12.5 percentage points in the fluticasone group and by 18.9+/-9.8 percentage points in the prednisone group four hours after therapy (P< 0.001). None of the children in the prednisone group had a reduction in FEV1 as a percentage of the predicted value from base line to four hours, as compared with 25 percent of those in the fluticasone group (P<0.001). Sixteen (31 percent) of the children treated with fluticasone were hospitalized, as compared with five (10 percent) of those treated with prednisone (P=0.01).

CONCLUSIONS

Children with severe acute asthma should be treated with oral prednisone and not with inhaled fluticasone or a similar inhaled corticosteroid.

Comparative cerebrospinal fluid diffusion of imipenem and meropenem in rats

The main objective of this study was to compare the cerebrospinal fluid (CSF) diffusion of imipenem and meropenem at steady state, following intravenous infusions at various rates in rats. A preliminary experiment was conducted to estimate the elimination half-lives of these two carbapenem antibiotics, and then to evaluate the infusion duration necessary to reach steady state. CSF diffusion of imipenem was essentially linear over the wide range of infusion rates (66-1,320microg min(-1)) and corresponding steady-state plasma concentrations (11.7-443.0 microg mL(-1)). Conversely the CSF diffusion of meropenem was saturable, with a predicted maximum CSF concentration equal to 1.3 microg mL(-1). Extrapolation of these data to the clinical situation may not be possible since the rats had normal blood-brain and blood-CSF barriers whereas patients with diseases such as meningitis may not. However, it is suggested that the observed differences in the diffusion characteristics of imipenem and meropenem may be partly responsible for their differences in toxicity and efficacy at the central level.

Pregnancy in cystic fibrosis. Fetal and maternal outcome

OBJECTIVE

To assess the effect of pregnancy on pulmonary function and survival in women with cystic fibrosis (CF) and to assess the fetal outcome.

DESIGN

Cohort study. The data analyzed were collected from the Toronto CF database, chart review, and patient questionnaire.

SETTING

Tertiary-care center.

PATIENTS

All women with CF who, at the time of diagnosis or pregnancy, attended the Toronto Cystic Fibrosis Clinics between 1961 and 1998.

RESULTS

From 1963 to 1998, there were 92 pregnancies in 54 women. There were 11 miscarriages and 7 therapeutic abortions. Forty-nine women gave birth to 74 children. The mean follow-up time was 11 +/- 8 years. One patient was lost to follow-up shortly after delivery, and one was lost after 12 years. The overall mortality rate was 19% (9 of 48 patients). Absence of Burkholderia cepacia (p < 0.001), pancreatic sufficiency (p = 0.01), and prepregnancy FEV(1) > 50% predicted (p = 0.03) were associated with better survival rates. When adjusted for the same parameters, pregnancy did not affect survival compared to the entire adult female CF population. The decline in FEV(1) was comparable to that in the total CF population. Three women had diabetes mellitus, and seven developed gestational diabetes. There were six preterm infants and one neonatal death. CF was diagnosed in two children.

CONCLUSIONS

The maternal and fetal outcome is good for most women with CF. Risk factors for mortality are similar to those for the nonpregnant CF population. Pregnancies should be planned so that there is opportunity for counseling and optimization of the medical condition. Good communication between the CF team and the obstetrician is important.

Imipenem but not meropenem induces convulsions in DBA/2 mice, unrelated to cerebrospinal fluid concentrations

Imipenem and meropenem CSF diffusion was comparable in DBA/2 mice but only imipenem induced convulsions, not related to CSF concentration.

Magnetic resonance imaging to distinguish the type and severity of pediatric inflammatory bowel diseases

BACKGROUND

The distinction between ulcerative colitis and Crohn's disease is important, because treatment options and clinical course may vary. Magnetic resonance imaging (MRI) allows noninvasive transmural assessment of the intestine and may facilitate differentiation of ulcerative colitis from Crohn's disease. The objective of this prospective study was to determine whether MRI differentiates Crohn's disease from ulcerative colitis in children as effectively as colonoscopy with mucosal biopsies.

METHODS

Fifteen patients underwent colonoscopy with biopsies followed by abdominal MRI. The MRI diagnosis, determined by two radiologists independently completing a standardized form was compared with the gastroenterologic diagnosis.

RESULTS

After colonoscopy and review of histology, Crohn's disease was diagnosed in nine patients, ulcerative colitis in five, and indeterminate colitis in one, who was excluded from study. Agreement of the MRI diagnosis with the gastroenterologic diagnosis was 4 of 4 (100%) for ulcerative colitis, 4 of 10 (40%) for Crohn's disease considering both radiologists, and 5 of 10 (50%) for Crohn's disease for each radiologist individually. Percentage of enhancement by MRI did not correlate with the severity of inflammation determined at endoscopy among the patients with Crohn's disease (r = -0.3, P = 0.366). There was agreement on severity of inflammation in three of four patients with ulcerative colitis.

CONCLUSIONS

Current MRI interpretation of inflammatory bowel disease did not adequately recognize Crohn's disease in children. Therefore, colonoscopy with biopsy remains the most accurate tool for determining the type and severity of inflammatory bowel disease in children and adolescents.