Pharmacokinetics of tildipirosin in estuarine (Crocodylus porosus) and freshwater (Crocodylus siamensis) crocodiles

Tildipirosin is a macrolide antimicrobial. It is authorised for the treatment and prevention of respiratory disease in cattle and pigs. There are no data on its administration in crocodiles. Therefore, this study evaluated the disposition kinetics of tildipirosin after intravenous (dose: 2 mg/kg) and intramuscular (doses: 2 and 4 mg/kg) administration in two crocodilian species (estuarine and freshwater; n = 5). Tildipirosin plasma concentrations were quantified by a validated HPLC method. Plasma concentrations obtained at each extraction time were analysed by non-compartmental methods. In the estuarine and freshwater crocodiles, the apparent volumes of distribution of tildipirosin after intravenous administration were 0.36 ± 0.10 and 1.48 ± 0.26 L/kg, respectively. These values, suggesting poorer tissue distribution, were much lower than those obtained in mammals. There was complete bioavailability of tildipirosin after intramuscular route at a dose of 2 mg/kg; however, at a dose of 4 mg/kg the bioavailability decreased by about 20-25 %. Furthermore, the pharmacokinetics of tildipirosin were markedly different in the two crocodilian species. Considering a MIC of 0.5 µg/mL, the surrogate marker AUC0-24/MIC indicates that tildipirosin would greatly exceed the value of 65 h for both crocodile species and dose levels tested. This suggests that both doses (2 and 4 mg/kg) may provide a bactericidal effect. Therefore, based on the absence of adverse reactions following the administration of tildipirosin in both crocodilian species, and considering its favourable pharmacokinetic properties, tildipirosin may be useful in treating infections in these reptiles.

Cephalosporin susceptibility of Staphylococcus aureus strains isolated from commercial rabbit and goats farms in Spain

Antimicrobial drug resistance is an important problem that challenges veterinary clinicians to provide effective treatments without further spreading resistance to other animals and people. The most commonly used pharmacodynamic parameter to define potency of antimicrobial drugs is minimum inhibitory concentration (MIC). The aim of this study was to evaluate the antibiotic susceptibility of thirty-six strains of Staphylococcus aureus isolated from dairy goats with mastitis and rabbits with chronic staphylococcosis. Four cephalosporins were tested: cephalexin, cephalotin, cefonicid and ceftiofur. MIC tests were performed according to the microdilution broth method. The calculated values of sensitivity in goats and rabbits were 66.67% and 72.22% for cephalexin, 72.22 % and 94.44% for cefonicid, 77.78% and 94.44% for cephalotin and 77.78% and 100% for ceftiofur, respectively. For all antibiotics, MIC90 of S. aureus from rabbits were lower than MIC90 from goats. These data suggest that more antibiotics are used in goat milk production than in rabbit farming. According to MIC values obtained in this study, ceftiofur and cephalotin may be the best option for treating S. aureus infections in lactating goats. For rabbits, ceftiofur showed lowest MIC values, therefore, it could be an alternative to treatment the infections caused by S. aureus in this species.

Susceptibility of caprine mastitis pathogens to tildipirosin, gamithromycin, oxytetracycline, and danofloxacin: effect of serum on the in vitro potency of current macrolides

Mastitis is a significant disease in dairy ruminants, causing economic losses to the livestock industry and severe risks to public health. Antibiotic therapy is one of the most crucial practices to treat mastitis, although the susceptibility of caprine mastitis pathogens to current antibiotics has not been tested under standard or modified incubation conditions. This work evaluated the in vitro activity of tildipirosin, gamithromycin, oxytetracycline, and danofloxacin against caprine mastitis pathogens incubated following standard conditions of Clinical and Laboratory Standards Institute (CLSI) and deviation method by 25% supplementation with goat serum. Mycoplasma agalactiae, Escherichia coli, Staphylococcus aureus, Streptococcus spp., and coagulase-negative Staphylococci (CNS) were isolated from dairy goats with mastitis in Spain. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution technique. The lowest MIC₉₀ under standard conditions was obtained with danofloxacin for mastitis-causing pathogens. An exception was M. agalactiae, where danofloxacin and oxytetracycline obtained low values. However, after adding serum, gamithromycin showed the lowest MIC₅₀ for S. aureus, Streptococcus spp., and CNS. The lowest MIC₅₀ was obtained with all the antibiotics tested (< 0.125 µg/ml) against M. agalactiae. Supplementing with serum resulted in a significant variation in tildipirosin and gamithromycin MIC values for CNS, S. aureus, M. agalagtiae, and E. coli. In brief, the MIC for antibiotics used against mastitis should be determined under conditions closely resembling intramammary infections to obtain representative susceptibility patterns against mastitis pathogens. Caprine mastitis pathogens were broadly susceptible to danofloxacin under standard conditions. The potency of macrolides against caprine mastitis pathogens increases when serum is present in culture media.

Efficacy and safety of intramuscular administration of allogeneic adipose tissue derived and expanded mesenchymal stromal cells in diabetic patients with critical limb ischemia with no possibility of revascularization: study protocol for a randomized controlled double-blind phase II clinical trial (The NOMA Trial)

Background

Chronic lower limb ischemia develops earlier and more frequently in patients with type 2 diabetes mellitus. Diabetes remains the main cause of lower-extremity non-traumatic amputations. Current medical treatment, based on antiplatelet therapy and statins, has demonstrated deficient improvement of the disease. In recent years, research has shown that it is possible to improve tissue perfusion through therapeutic angiogenesis. Both in animal models and humans, it has been shown that cell therapy can induce therapeutic angiogenesis, making mesenchymal stromal cell-based therapy one of the most promising therapeutic alternatives. The aim of this study is to evaluate the feasibility, safety, and efficacy of cell therapy based on mesenchymal stromal cells derived from adipose tissue intramuscular administration to patients with type 2 diabetes mellitus with critical limb ischemia and without possibility of revascularization.

Methods

A multicenter, randomized double-blind, placebo-controlled trial has been designed. Ninety eligible patients will be randomly assigned at a ratio 1:1:1 to one of the following: control group (n = 30), low-cell dose treatment group (n = 30), and high-cell dose treatment group (n = 30). Treatment will be administered in a single-dose way and patients will be followed for 12 months. Primary outcome (safety) will be evaluated by measuring the rate of adverse events within the study period. Secondary outcomes (efficacy) will be measured by assessing clinical, analytical, and imaging-test parameters. Tertiary outcome (quality of life) will be evaluated with SF-12 and VascuQol-6 scales.

Discussion

Chronic lower limb ischemia has limited therapeutic options and constitutes a public health problem in both developed and underdeveloped countries. Given that the current treatment is not established in daily clinical practice, it is essential to provide evidence-based data that allow taking a step forward in its clinical development. Also, the multidisciplinary coordination exercise needed to develop this clinical trial protocol will undoubtfully be useful to conduct academic clinical trials in the field of cell therapy in the near future.

Trial registration

ClinicalTrials.govNCT04466007. Registered on January 07, 2020. All items from the World Health Organization Trial Registration Data Set are included within the body of the protocol.

Enrofloxacin and its major metabolite ciprofloxacin in green sea turtles (Chelonia mydas): An explorative pharmacokinetic study

The present study aimed to assess the pharmacokinetic features of enrofloxacin (ENR) and its major metabolite, ciprofloxacin (CIP) in green sea turtles (Chelonia mydas) after single intravenous (i.v.) and intramuscular (i.m.) administration at two dosages of 5 and 7.5 mg/kg body weight (b.w.). The study used 10 animals randomly divided into equal groups. Blood samples were collected at assigned times up to 168 hr. The concentrations of ENR and CIP in turtle plasma were quantified by a validated high-performance liquid chromatography equipped with fluorescence detector (HPLC-FLD). The concentration of ENR in the experimental turtles with respect to time was pharmacokinetically analyzed using a noncompartment model. The concentrations of ENR in the plasma were quantified up to 144 hr after i.v. and i.m. administrations at dosages of 5 and 7.5 mg/kg b.w., whereas CIP was quantified up to 96 and 144 hr, respectively. The elimination half-life values of ENR were 38.7 and 50.4 hr at dose rates of 5 and 7.5 mg/kg b.w. after i.v. administration, whereas CIP was 33.6 and 22.6 hr, respectively. The maximum concentration (C_max ) values of ENR were 2.07 and 2.59 μg/ml at dose rates of 5 and 7.5 mg/kg b.w., respectively. The value of area under the curve from 0 to 24 hr (AUC_0-24 )/minimum inhibitory concentration (MIC) ratio of ENR was >125 for bacteria with MIC of 0.12 and 0.13 μg/ml after the administration of 5 mg/kg by i.m. and i.v. administration, respectively. Based on the pharmacokinetic data, susceptibility break-point and pharmacokinetic (PK)/pharmacodynamic (PD) indices, i.m. single administration of ENR at a dosage of 5 mg/kg b.w. might be clinically appropriate for treatment of susceptible bacteria in green sea turtles (Chelonia mydas).

41BB-based and CD28-based CD123-redirected T-cells ablate human normal hematopoiesis in vivo

BACKGROUND

Acute myeloid leukemia (AML) is a hematopoietic malignancy which is biologically, phenotypically and genetically very heterogeneous. Outcome of patients with AML remains dismal, highlighting the need for improved, less toxic therapies. Chimeric antigen receptor T-cell (CART) immunotherapies for patients with refractory or relapse (R/R) AML are challenging because of the absence of a universal pan-AML target antigen and the shared expression of target antigens with normal hematopoietic stem/progenitor cells (HSPCs), which may lead to life-threating on-target/off-tumor cytotoxicity. CD33-redirected and CD123-redirected CARTs for AML are in advanced preclinical and clinical development, and they exhibit robust antileukemic activity. However, preclinical and clinical controversy exists on whether such CARTs are myeloablative.

METHODS

We set out to comparatively characterize in vitro and in vivo the efficacy and safety of 41BB-based and CD28-based CARCD123. We analyzed 97 diagnostic and relapse AML primary samples to investigate whether CD123 is a suitable immunotherapeutic target, and we used several xenograft models and in vitro assays to assess the myeloablative potential of our second-generation CD123 CARTs.

RESULTS

Here, we show that CD123 represents a bona fide target for AML and show that both 41BB-based and CD28-based CD123 CARTs are very efficient in eliminating both AML cell lines and primary cells in vitro and in vivo. However, both 41BB-based and CD28-based CD123 CARTs ablate normal human hematopoiesis and prevent the establishment of de novo hematopoietic reconstitution by targeting both immature and myeloid HSPCs.

CONCLUSIONS

This study calls for caution when clinically implementing CD123 CARTs, encouraging its preferential use as a bridge to allo-HSCT in patients with R/R AML.

Measurement of the magnetic permeability of amorphous magnetic microwires by using their antenna resonance

We present here a new free space method to measure the magnetic permeability of a single amorphous magnetic microwire (AMM) at microwave frequencies. The technique consists in inducing a high frequency electric current along the AMM axis by illumination with an electromagnetic wave at antenna resonance conditions. Fitting the induced electric current to the Hallen-Pocklington equation allows computing the relative magnetic permeability of the microwire as a function of the wave frequency. The method results particularly useful for the study of the giant magnetoimpedance effect of AMM by measuring the magnetic permeability upon the application of DC magnetic fields.

Tuning Metamaterials by using Amorphous Magnetic Microwires

In this work, we demonstrate theoretically and experimentally the possibility of tuning the electromagnetic properties of metamaterials with magnetic fields by incorporating amorphous magnetic microwires. The large permeability of these wires at microwave frequencies allows tuning the resonance of the metamaterial by using magnetic fields of the order of tens of Oe. We describe here the physical basis of the interaction between a prototypical magnetic metamaterial with magnetic microwires and electromagnetic waves plus providing detailed calculations and experimental results for the case of an array of Split Ring Resonators with Co-based microwires.

Using melanopsin to study G protein signaling in cortical neurons

Our understanding of G protein-coupled receptors (GPCRs) in the central nervous system (CNS) has been hampered by the limited availability of tools allowing for the study of their signaling with precise temporal control. To overcome this, we tested the utility of the bistable mammalian opsin melanopsin to examine G protein signaling in CNS neurons. Specifically, we used biolistic (gene gun) approaches to transfect melanopsin into cortical pyramidal cells maintained in organotypic slice culture. Whole cell recordings from transfected neurons indicated that application of blue light effectively activated the transfected melanopsin to elicit the canonical biphasic modulation of membrane excitability previously associated with the activation of GPCRs coupling to Gαq-11 Remarkably, full mimicry of exogenous agonist concentration could be obtained with pulses as short as a few milliseconds, suggesting that their triggering required a single melanopsin activation-deactivation cycle. The resulting temporal control over melanopsin activation allowed us to compare the activation kinetics of different components of the electrophysiological response. We also replaced the intracellular loops of melanopsin with those of the 5-HT2A receptor to create a light-activated GPCR capable of interacting with the 5-HT2A receptor interacting proteins. The resulting chimera expressed weak activity but validated the potential usefulness of melanopsin as a tool for the study of G protein signaling in CNS neurons.

Chitinase 3-like proteins as diagnostic and prognostic biomarkers of multiple sclerosis

Background:

Despite sensitivity of MRI to diagnose multiple sclerosis (MS), prognostic biomarkers are still needed for optimized treatment.

Objective:

The objective of this paper is to identify cerebrospinal fluid (CSF) diagnostic biomarkers of MS using quantitative proteomics and to analyze their expression at different disease stages.

Methods:

We conducted differential analysis of the CSF proteome from control and relapsing–remitting MS (RRMS) patients followed by verification by ELISA of candidate biomarkers in CSF and serum in control, clinically isolated syndrome (CIS), RRMS and progressive MS (PMS) patients.

Results:

Twenty-two of the 527 quantified proteins exhibited different abundances in control and RRMS CSF. These include chitinase 3-like protein 1 (CHI3L1) and 2 (CHI3L2), which showed a strong expression in brain of MS patients, especially in astrocytes and microglial cells from white matter plaques. CSF and serum CHI3L1 levels increased with the disease stage and CIS patients with high CSF (>189 ng/ml) and serum (>33 ng/ml) CHI3L1 converted more rapidly to RRMS (log rank test, p < 0.05 and p < 0.001, respectively). In contrast, CSF CHI3L2 levels were lower in PMS than in RRMS patients. Accordingly, CSF CHI3L1/CHI3L2 ratio accurately discriminated PMS from RRMS.

Conclusions:

CSF CHI3L1 and CHI3L2 and serum CHI3L1 might help to define MS disease stage and have a prognostic value in CIS.

Performance of an in-situ rotating biological contactor in a recirculating aquaculture system

The start-up and activation of a nitrifying rotating biological contactor (RBC) and its performance inside a culture tank of rainbow trout were studied. First, in a lab-scale operation, the system was fed with a synthetic medium containing a high ammonia concentration (567 mg NH(4)(+)-N L(-1)) and operated at a high hydraulic retention time (HRT) (6.5 days) to minimize the wash-out of the biomass and promote the biofilm formation. Then, both inlet ammonia concentration and HRT were decreased in order to obtain operational conditions similar to those of the culture tank. During this period, the RBC was able to treat an ammonia loading rate (ALR) of 0.64 g N-NH(4)(+) L(-1) d(-1) with a removal efficiency within 70-100%. Pilot-scale experiments were carried out in culture tanks of rainbow trout. The operation of a recirculating system with the RBC unit was compared with a recirculating system without biological treatment and with a flow-through system. The use of this in-situ nitrifying unit allowed working at a recirculation ratio of 90% without negative effects on either growth or the condition factor of fishes. Up to 70% of ammonia generated was removed and a removal rate of 1.41 g NH(4)(+)-N m(-2) d(-1) was reached.

PPP in urban water: lessons from Yerevan, Armenia

Recent literature on public–private partnerships (PPPs) in urban water supply and sanitation (WSS) services tends to concentrate on distressed projects, especially when high-profile concessions are cancelled. Successful projects get comparatively little attention, contributing to the impression that water PPPs do not work. The management contract in Yerevan, Armenia is one example in which private sector participation in WSS service provision has brought benefits to the population, and has been endorsed satisfactorily by the government and national stakeholders. This paper discusses the process and outcomes of Yerevan’s management contract (2000–2005), and highlights important lessons for policy-makers and reformers. Based on available data, the authors find evidence of improvements in the quality of services, collections, and energy efficiency, but only modest improvements in technical efficiency. The case study holds valuable lessons for other developing countries, as some challenges had to be faced during implementation. It shows ultimately that, to realise benefits from a management contract, both parties must be willing to make it work, and build over time a true partnership.

Oxidative burst assessment and neutrophil-platelet complexes in unlysed whole blood

BACKGROUND

Methods currently employed for measuring reactive oxygen species production can lead to both cellular depletion and in artifactual activation. The objective of this study was to design a methodology allowing the measurement of oxidative burst (OB) with minimal sample manipulation.

METHODS

To that purpose a flow cytometry technique developed in our laboratory, based on nucleic acid staining to discriminate erythrocytes and debris, was employed. DRAQ5 dye and PECy5-CD45 monoclonal antibody (MoAb) were simultaneously used in FL3 to identify the leukocyte population and the PE-CD14 MoAb emission was detected in FL2 for monocytes. OB was measured by using the fluorogenic probe dihydrorhodamine 123, a marker of hydrogen peroxide production. Phorbol myristate acetate (PMA), Opsonized Zymosan (OZ), fMLP and calcium ionophore A23187 activators were also used in this study. For OB assays, dose-response curves were performed for each activator. In addition, the effect of activator concentration on annexin V binding, as a measure of phosphatidylserine translocation, was evaluated.

RESULTS

With this method no-lysis and no-wash steps are required, thus avoiding an unwanted damage to leukocytes. PMA and Zymosan produced an increase in annexin V binding, while fMLP and calcium ionophore did not.

CONCLUSIONS

This study reports a feasible and reproducible new flow cytometry assay for assessing OB of neutrophils and monocytes with minimal sample manipulation. In addition, under PMA and OZ conditions, the number of neutrophils showing annexin V binding was strikingly increased. This effect is not related with a phagocytic overstimulation, but with an increased neutrophil-platelet complexes formation.

Differential expression of CD150 (SLAM) family receptors by human hematopoietic stem and progenitor cells

OBJECTIVES

Human hematopoietic stem cell (HSC)-containing grafts are most commonly used to treat various blood diseases, including leukemias and autoimmune disorders. CD150 (SLAM) family receptors have recently been shown to be differentially expressed by mouse HSC and progenitor cells. Members of the CD150 family are key regulators of leukocyte activation and differentiation. The goal of the present study is to analyze the expression patterns of the CD150 receptors CD48, CD84, CD150 (SLAM), CD229 (Ly9), and CD244 (2B4) on the different sources of human hematopoietic stem and progenitor cells.

MATERIALS AND METHODS

Expression of CD150 receptors was analyzed on human mobilized peripheral blood CD133(+)-isolated cells and CD34(+) bone marrow (BM) and umbilical cord blood (CB) cells using multicolor flow cytometry.

RESULTS

CD244 was present on most CD133(+)Lin(-)-mobilized cells and CD34(+)Lin(-) BM and CB cells, including virtually all CD38(-)Lin(-) primitive progenitor cells. CD48 had a restricted expression pattern on CD133(+)Lin(-)CD38(-) cells, while its levels were significantly higher in CD34(+)Lin(-) BM and CB cells. In addition, CD84 was present on a significant number of CD133(+)Lin(-) cells, but only on a small fraction of CD133(+)Lin(-)CD38(-) peripheral blood mobilized cells. In contrast, CD84 was expressed on practically all CD34(+)Lin(-) BM cells. No CD150 expression was observed in mobilized peripheral blood CD133(+)Lin(-) or CD34(+)Lin(-) BM and CB cells. Furthermore, only a small fraction of CD34(+)Lin(-) BM and CB cells expressed CD229.

CONCLUSIONS

Our results show that CD150 family molecules are present on human hematopoietic stem and progenitor cells and that their expression patterns differ between humans and mice.

Physical interaction between the serotonin transporter and neuronal nitric oxide synthase underlies reciprocal modulation of their activity

The spatiotemporal regulation of neurotransmitter transporters involves proteins that interact with their intracellular domains. Using a proteomic approach, we identified several proteins that interact with the C terminus of the serotonin transporter (SERT). These included neuronal nitric oxide synthase (nNOS), a PSD-95/Disc large/ZO-1 (PDZ) domain-containing protein recruited by the atypical PDZ binding motif of SERT. Coexpression of nNOS with SERT in HEK293 cells decreased SERT cell surface localization and 5-hydroxytryptamine (5-HT) uptake. These effects were absent in cells transfected with SERT mutated in its PDZ motif to prevent physical association with nNOS, and 5-HT uptake was unaffected by activation or inhibition of nNOS enzymatic activity. 5-HT uptake into brain synaptosomes was increased in both nNOS-deficient and wild-type mice i.v. injected with a membrane-permeant peptidyl mimetic of SERT C terminus, which disrupted interaction between SERT and nNOS, suggesting that nNOS reduces SERT activity in vivo. Furthermore, treating cultured mesencephalic neurons with the mimetic peptide similarly increased 5-HT uptake. Reciprocally, indicating that 5-HT uptake stimulates nNOS activity, NO production was enhanced on exposure of cells cotransfected with nNOS and SERT to 5-HT. This effect was abolished by 5-HT uptake inhibitors and absent in cells expressing SERT mutated in its PDZ motif. In conclusion, physical association between nNOS and SERT provides a molecular substrate for their reciprocal functional modulation. In addition to showing that nNOS controls cell surface localization of SERT, these findings provide evidence for regulation of cellular signaling (NO production) by a substrate-carrying transporter.

Pharmacokinetic-pharmacodynamic integration of danofloxacin after intravenous, intramuscular and subcutaneous administration to rabbits

The pharmacokinetics of danofloxacin was studied following intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) administration of 6 mg/kg to healthy rabbits. Danofloxacin concentration were determined by high-performance liquid chromatography assay with fluorescence detection. Minimal inhibitory concentrations (MICs) assay of danofloxacin against 30 strains of Staphylococcus aureus from several European countries was performed in order to compute pharmacodynamic surrogate markers. The danofloxacin plasma concentration versus time data after i.v. administration could best be described by a two-compartment open model. The disposition of i.m. and subcutaneously administered danofloxacin was best described by a one-compartment model. The terminal half-life for i.v., i.m. and s.c. routes was 4.88, 6.70 and 8.20 h, respectively. Clearance value after i.v. dosing was 0.76 L/kg.h. After i.m. administration, the absolute bioavailability was mean (+/-SD) 102.34 +/- 5.17% and the Cmax was 1.87 mg/L. After s.c. administration, the absolute bioavailability was mean (+/-SD) 96.44 +/- 5.95% and the Cmax was 1.79 mg/L. Danofloxacin shows a favourable pharmacokinetics profile in rabbits reflected by parameters such as a long half-life and a high bioavailability. However, in consideration of the low AUC/MIC indices obtained, its use by i.m. and s.c. route against the S. aureus strains assayed in this study cannot be recommended given the risk for selection of first mutant subpopulations.

Flow cytometry of the Side Population: tips & tricks

Background: The Side Population (SP) has become an important hallmark for the definition of the stem cell compartment, especially in the detection of these cells and in their physical isolation by fluorescence-activated cell sorting (FACS). SP cells are CD34^neg and were discovered using ultraviolet excitation based on the efflux of Hoechst 33342 (Ho342). Although the method works as originally described, we believe that this method is difficult for most investigators. First, because the ability to discriminate SP cells is based on the differential retention of Ho342 during a functional assay; second, because of the difficulties in setting the right experimental and acquisition conditions; and third, because the analysis of the acquired data requires an extensive expertise on flow cytometry to accurately detect the SP events. Methods: First of all and mainly for the SP application, the laser beam paths were exhaustively checked to ensure the lowest coefficients of variation. Blood suspensions were prepared by erythrocyte lysis with ammonium chloride and hematopoietic cells were labeled with Ho342. Results: The Ho342 concentration and the staining procedure are critical for the optimal resolution of the SP cells. Although UV laser alignment is very important to resolve the dim tail that outlines the SP, the problem with Ho342 excitation is not the Hoechst Blue emission, but rather the Hoechst Red's (because of the weak emission). Conclusions: Each laboratory must establish its own expected ranges based on its instrument and results may vary slightly due to instrument differences such as the narrowness of the band pass filters, laser power, laser emission wavelength, nozzle type, differential of pressure, light collection system (cuvette versus jet-in-air) and beam shaping optics.

GPCR-interacting proteins (GIPs): nature and functions

The simplistic idea that seven transmembrane receptors are single monomeric proteins that interact with heterotrimeric G-proteins after agonist binding is definitively out of date. Indeed, GPCRs (G-protein-coupled receptors) are part of multiprotein networks organized around scaffolding proteins. These GIPs (GPCR-interacting proteins) are either transmembrane or cytosolic proteins. Proteomic approaches can be used to get global pictures of these 'receptosomes'. This approach allowed us to identify direct but also indirect binding partners of serotonin receptors. GIPs are involved in a wide range of functions including control of the targeting, trafficking and signalling of GPCRs. One of them, Shank, which is a secondary and tertiary partner of metabotropic and ionotropic glutamate receptors, respectively, can induce the formation of a whole functional glutamate 'receptosome' and the structure to which it is associated, the dendritic spine.

A rare fraction of human hematopoietic stem cells with large telomeres

The lack of specific markers for stem cells makes the physical identification of this compartment difficult. Hematopoietic stem cells differ in their repopulating and self-renewal potential. Our study shows that multiple classes of human hematopoietic CD34+ greatly differ in telomere length. Flow-cytometry-based fluorescent in situ hybridization and confocal microscopy of CD34+ cells has revealed remarkable telomere length heterogeneity, with a hybridization pattern consistent with different classes of human hematopoietic progenitor cells. These results also point to the existence of a significant clonal heterogeneity among primitive hematopoietic cells and provide the first evidence of a rare fraction of CD34+ cells with large telomeres in humans.

Flow cytometry-based approach to ABCG2 function suggests that the transporter differentially handles the influx and efflux of drugs

BACKGROUND

To better characterize the function of the ABCG2 transporter in vitro, we generated three cell lines (MXRA, MXRG, and MXRT) stably expressing ABCG2 after transfection of wild-type ABCG2 and two mutants (R482G and R482T), respectively.

METHODS

ABCG2 expression and function were analyzed by flow cytometry using monoclonal antibodies, a variety of fluorescent substrates, and a series of potential inhibitors of the transporter.

RESULTS

ABCG2 expression was detected in all cell lines. The cell lines effluxed mitoxantrone (MXR), but only the mutants effluxed rhodamine 123 (Rho123), SYTO13, doxorubicin, and daunorubicin. After incubation with MXR, intracellular accumulations were 9- and 22-fold higher in MXRA than in MXRT and MXRG cells, respectively, suggesting that ABCG2 also modulates the influx rate of the drug. Flow cytometry kinetic studies of MXR efflux showed that MXRG cells effluxed 50% of the drug at a faster rate than MXRA and MXRT cells (t50: 15.3 min vs. 27.8 and 44.5 min, respectively). MXRG cells also extruded Rho123 and SYTO13 at a faster rate than MXRT cells. ABCG2-mediated transport was inhibited by fumitremorgin C, cyclosporine A, and PSC-833, but not by verapamil or probenecid. MXRG cells displayed the highest level of resistance to MXR, doxorubicin, and daunorubicin in the cytotoxicity assays.

CONCLUSIONS

Glycine mutations at position 482 have a significant impact on ABCG2 function by modifying its substrate specificity and its influx/efflux rates. This study also demonstrates that flow cytometry constitutes a powerful tool for the kinetic analysis of ABC transporters.

G-CSF increases the expression of VCAM-1 on stromal cells promoting the adhesion of CD34+ hematopoietic cells: studies under flow conditions

OBJECTIVE AND METHODS

The knowledge of the mechanisms underlying the adhesive processes that lead to homing and/or mobilization of hematopoietic progenitor cells, and the influence of blood rheology, is still limited. We analyzed the impact of flow conditions on the adhesion of CD34+ peripheral blood progenitor cell (PBPC) to the adhesive proteins fibronectin, laminin, and collagen, and to stromal cells.

RESULTS

Under static conditions, all the adhesive substrata assayed promoted adhesion of CD34+ PBPC, being higher on the stromal cells. Under flow conditions, adhesion of CD34+ PBPC was remarkable on stromal cells while insignificant onto the purified proteins. Exposure of stromal cell monolayers to granulocyte colony-stimulating factor (G-CSF) further enhanced PBPC adhesion. This effect correlated with the activation of p38 MAPK and with an increase in the expression of VCAM-1 on stromal cells exposed to G-CSF. In inhibitory assays, both an antibody to the G-CSFR and a specific inhibitor of the p38 MAPK blocked the effects induced by the cytokine.

CONCLUSION

Our results provide direct evidence that in stromal cells G-CSF activates the signaling protein p38 MAPK, inducing expression of the adhesion receptor VCAM-1. This mechanism seems to promote adhesion of CD34+ cells on stromal cells and could play a potential role in homing events.

High-dose therapy/autologous stem cell transplantation in patients with chemosensitive multiple myeloma: predictors of complete remission

High-dose therapy (HDT) followed by autologous stem cell support is widely used as intensification treatment in patients with multiple myeloma (MM) responsive to the initial chemotherapy. However, there is growing evidence that only the subset of patients who achieve complete remission (CR) actually benefit from this approach. The aim of this study was to identify pretransplant predictors of CR in responding myeloma patients intensified with HDT. A total of 59 patients with chemosensitive disease received myeloablative therapy. The intensification regimen consisted of MEL-200 (23), MEL-140/TBI 12 Gy (21) or busulfan-based regimens (15). Serum and urine negative immunofixation were required for CR. After HDT, the CR rate increased from 8 to 37%. For the overall series, the median event-free survival (EFS) and overall survival (OS) from the initiation of therapy were 41 and 68 months, respectively. Patients who achieved CR had an EFS (median 47 vs 36 months; P=0.023) as well as an OS (median not reached vs 60 months; P=0.006) significantly longer than those attaining a lower degree of response. Finally, the pretransplant features significantly associated to CR were a low M-protein size (serum </=10 g/l and urine <0.5 g/24 h) (P=0.0003) and a proportion of bone marrow plasma cells of </=5% (P=0.02).

Polymorphisms of the angiotensinogen gene and the outcome of microalbuminuria in essential hypertension: a 3-year follow-up study

BACKGROUND

The objective of this study was to analyse the relationship of polymorphisms of the angiotensinogen (AGT) gene with the changes in microalbuminuria during 3 years of antihypertensive treatment in a group of young adults with essential hypertension.

METHODS

Essential hypertensives, less than 50 years old, never previously treated with antihypertensive drugs and in the absence of diabetes mellitus were included. After the initial evaluation, patients were treated using only nonpharmacological measures (n=23), only beta-blockers (n=26), only angiotensin-converting enzyme inhibitors (ACEi) (n=57) or a combination of treatments (n=25). The office blood pressure, biochemical profile and urinary albumin excretion (UAE) were measured at the beginning and then yearly. The polymorphism A-6G of the AGT gene located in the promoter region was analysed.

RESULTS

In total, 131 patients, 35 (27%) microalbuminurics, were included. Although no significant differences in systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting glucose and UAE were observed among genotypes at the initial examination, during the 3 years of antihypertensive treatment the slope values for the DBP, fasting glucose and UAE differed significantly despite no differences in the distribution of treatments being present. The subjects carrying the AA-6 genotype had the largest DBP decrease, but the lowest UAE reduction and the highest slope of glucose. Out of 35 initially microalbuminuric patients, 24 became normoalbuminuric and the lowest reduction rates were observed in subjects who carried the allele A-6. No interaction between the type of treatment and genotype was observed on the changes in UAE, BP or glucose values. In the subset of 57 patients treated with ACEi, the changes in UAE, BP and glucose had the same trend as was observed in the total population.

CONCLUSIONS

Subjects carrying the AA genotype of the A-6G AGT gene polymorphism are resistant to a reduction of microalbuminuria. Whether this can be attributed to a predisposition to glucose metabolic disturbance or not needs to be confirmed in further studies.

Flow cytometric-based isolation of nucleated erythroid cells during maturation: an approach to cell surface antigen studies

Nucleated red blood cells (NRBCs) are involved in normal physiologic processes, as well as in several malignancies. They are usually counted manually under the microscope. However, blood sample manipulation may be a source of variability and manual counting is imprecise, time-consuming, and subjective. To improve identification of CD45-negative cells, we used a flow cytometry technique that avoids the addition of lysing reagents and stains viable cell nuclei. We applied this method for counting and isolating NRBC subpopulations in whole blood samples, using DNA/RNA viable staining to discriminate nonnucleated erythroid cells and debris. NRBC counts gave 197.95 cells per mm(3) in mobilized peripheral blood samples (1.00%, n = 20), 3897.59 cells per mm(3) in leukapheresis products (3.08%, n = 20), and 765.21 cells per mm(3) in cord blood samples (6.09%, n = 20). Normal bone marrow counts were 5449.42 cells per mm(3) (11.76%, n = 20). Scatter profiles showed three distinct populations, from early to late-stage erythroblasts, consisting of erythroblasts, orthochromatic erythroblasts, and ejected nuclei, as confirmed by Wright-Giemsa staining. In addition, flow cytometry immunophenotyping showed that glycophorin A was expressed dimly on NRBCs during maturation. These findings point to the feasibility of live NRBCs studies, which offer great potential for a wide range of disciplines.

A multicolor, no-lyse no-wash assay for the absolute counting of CD34+ cells by flow cytometry

BACKGROUND

We previously developed a method for counting CD34(+) cells in unlysed whole blood. This method was applied to normal human bone marrow, peripheral blood after mobilization of progenitor cells, leukapheresis products, and cord blood and was validated with two different lyse-no wash methods. However, the main advantage that we described, erythrocyte discrimination using nucleic acid staining, was also the main restriction because additional markers for the immunologic characterization of CD34(+) cells cannot be included.

METHODS

We used SYTO-13 and fluorescein isothiocyanate (FITC)-CD45 staining (FL1) instead of SYTO-13 and phycoerythrin (PE)Cy5-CD45 staining (FL3) to leave the third and fourth fluorescence parameters available for further characterization of CD34(+) cells. The new method was validated by applying it to cord blood samples (n = 20).

RESULTS

FITC-CD45 antibody gave a 1.7-fold increase in mean fluorescence intensity over SYTO-13 alone. From absolute counts (CD34(+) cells per microliter), we plotted the differences between the methods against their mean, showing that differences fell into acceptable ranges.

CONCLUSIONS

No-lyse procedures may represent an advance for cell immunophenotyping and it could be applied to the measurement of additional markers. Cytometry (Clin. Cytometry) 50:249-253, 2002.

Body weight changes and the A-6G polymorphism of the angiotensinogen gene

BACKGROUND

The objective of the study was to analyze the relationship of polymorphisms of the angiotensinogen gene with changes in body weight during 3 y of antihypertensive treatment, in a group of young adults with essential hypertension.

METHODS

Essential hypertensives, less than 50 y old, never previously treated with antihypertensive drugs and in the absence of diabetes mellitus were included. After the initial evaluation, patients were treated using only non-pharmacological measures (n=29), beta-blockers (n=40) or angiotensin-converting enzyme inhibitors (n=66). Resting blood pressure, biochemical profile and body weight at the beginning and yearly were measured. The polymorphism A-6G of the angiotensinogen gene located in the promoter region was analyzed.

RESULTS

One-hundred and thirty-five patients were included. Genotypes of the A-6G polymorphism of the AGT gene were in Hardy-Weinberg equilibrium (AA 34, AG 63, GG 38). No significant differences were observed among genotypes in terms of age, body mass index, body weight, systolic or diastolic blood pressure. No significant differences in the genotype distribution or in the allele frequencies were observed, although the A allele was most frequent among the obese subjects. During the 3 y of antihypertensive treatment, there was a trend to increase weight despite the dietary recommendations. The slopes of body weight over time, adjusted by age and baseline BMI, differed significantly among the homozygote genotypes (P=0.006). The highest were for those with the AA genotype and the lowest for the GG genotype (1.180+/-0.25 and -0.128+/-0.24 kg/y; P=0.0001). The influence of the genotype in the changes on body weight remained significant after considering its interaction with the kind of antihypertensive treatment, although among subjects carrying the AA genotype those treated with ACEi showed the least body weight change. Furthermore, A-6G genotypes had the largest influence on weight changes, accounting for 19% of the variance, when age, sex and initial body mass index were included in the model.

CONCLUSIONS

In a group of young adult hypertensive subjects, there was a trend to increase weight despite dietary recommendations. Subjects with the AA genotype were those with the largest weight gain, but this effect was modified by the antihypertensive treatment.

Outcome of pregnancy and disease course among women with aplastic anemia treated with immunosuppression

BACKGROUND

Aplastic anemia may develop during pregnancy and sometimes improves spontaneously after delivery. The effects of pregnancy on aplastic anemia after immunosuppressive treatment and of aplastic anemia on the outcome of pregnancy have not been described.

OBJECTIVE

To determine the outcome of pregnancy and the disease course among women with aplastic anemia who received immunosuppressive therapy.

DESIGN

Retrospective multicenter study.

SETTING

Twelve centers participating in the European Group for Blood and Marrow Transplantation.

PATIENTS

36 women who received immunosuppressive therapy to treat aplastic anemia.

MEASUREMENTS

Outcomes of pregnancy and aplastic anemia and blood counts before, during, and after delivery.

RESULTS

The 36 pregnancies resulted in 34 live births (one set of twins), 2 elective abortions, and 1 spontaneous abortion. Of the 36 pregnancies, 22 were uncomplicated and 14 involved medical complications. Seven pregnancies (19%) were complicated by relapse of aplastic anemia, and 5 patients without relapse (14%) needed transfusions during delivery. After delivery, 3 of the 7 patients who had relapse recovered spontaneously and 3 recovered after retreatment. One patient who did not respond to treatment died of aplastic anemia. A woman with aplastic anemia and paroxysmal nocturnal hemoglobinuria had a fatal cerebral thrombosis after delivery. Women with uneventful pregnancies had better prepregnancy remission status (8 complete and 11 partial remissions) and a higher median platelet count (146 x 10(9) cells/L) than did women with complicated pregnancies (2 complete remissions, 8 partial remissions, and 4 cases of paroxysmal nocturnal hemoglobinuria; median platelet count, 92 x 10(9) cells/L).

CONCLUSIONS

Successful pregnancy with normal outcome is possible in women with aplastic anemia previously treated with immunosuppression. Complications appear to be more likely in patients with low platelet counts and paroxysmal nocturnal hemoglobinuria-associated aplastic anemia.

Both Astrocytes and Neurons Contribute to the Potentiation Mediated by alpha1-Adrenoceptors of the beta-Adrenergic-Stimulated Cyclic AMP Production in Brain

Using primary neuronal or astrocyte cultures from the striatum of the embryonic mouse, we have observed that the beta-adrenergic agonist isoprenaline (10-5 M) induced a more pronounced accumulation of cAMP in astrocytes than in neurons. In both cell types, the alpha-adrenergic selective agonist methoxamine (10-4 M), which alone did not affect the production of cAMP, potentiated the isoprenaline-evoked response. In support of these observations, when associated alpha2-noradrenergic and D1-dopaminergic responses were prevented, the mixed alpha1- and beta-adrenergic agonist noradrenaline (10-5 M) induced a production of cAMP which was totally blocked by propranolol (10-6 M) and partially abolished by prazosin (10-6 M). Since experiments were made in the presence of 3-isobutyl-1-methylxanthine (1 mM), the observed effects of cAMP accumulation were not related to a modulation of phosphodiesterase activities. In addition, both in astrocytes and in neurons, the potentiation by alpha1-adrenergic agonists of the beta-adrenergic-evoked response required external calcium. Using INDo 1 as a fluorescent probe, methoxamine (25 microM) was shown to induce in astrocytes an increase in cytosolic calcium concentration which was prolonged by isoprenaline (10-5 M) only in the presence of external calcium. These results suggest that the prolonged increase in cytosolic calcium concentration linked to the activation of alpha1- and beta-adrenergic receptors is responsible for the potentiation of the beta-adrenergic-induced production of cAMP, which is partially dependent on external calcium.

A Nitric Oxide Synthase Activity Selectively Stimulated by NMDA Receptors Depends on Protein Kinase C Activation in Mouse Striatal Neurons

In mouse striatal neurons in primary culture, the maximal increase in intracellular cyclic guanosine monophosphate level evoked by N-methyl-d-aspartic acid (NMDA) receptor activation was twice that induced by kainate, KCl and ionomycin. Quisqualate was almost inactive. All responses were mediated by nitric oxide (NO) production since they were blocked by haemoglobin (a NO scavenger) and by l-NG-monomethylarginine and l-NG-nitroarginine, the effects of both arginine analogues being reversed by an excess of l-arginine. Several results indicate that NMDA receptors stimulate a specific NO synthase activity. This specifically NMDA-activated NO synthase was blocked by nanomolar concentrations of l-NG-nitroarginine, whereas the responses evoked by other agents, including kainate, KCl and ionomycin, were only blocked by micromolar concentrations of this NO synthase inhibitor. The NMDA response could not be totally reproduced by an increase in cytosolic calcium (Ca2+) alone. In contrast, in the presence of staurosporine, an inhibitor of protein kinases C (PKC), as well as after desensitization of PKC induced by long-term treatment with the phorbol ester, phorbol-12, 13-dibutyrate, NMDA-stimulated NO production was selectively reduced, reaching the level evoked by kainate or Ca2+ increase. In conclusion, our results suggest that in striatal neurons, NMDA selectively stimulates a NO synthase activity which is inhibited by low concentrations of l-NG-nitro-arginine, through a mechanism involving PKC.

AMPA receptor activation induces association of G-beta protein with the alpha subunit of the sodium channel in neurons

Glutamatergic transmission is mediated by ionotropic receptors that directly gate cationic channels and metabotropic receptors that are coupled to second messenger generating systems and to ionic channels via heterotrimeric guanine-nucleotide binding- (G) proteins. This distinction cannot be made for the ionotropic receptor subclass activated by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), which has been shown to be physically associated with the alpha-subunit of Gi1 protein and activates this G-protein. Here, we report that, in addition to a Ca2+ influx, AMPA induces the mobilization of Ca2+ from the mitochondrial pool by reversing the mitochondrial Na+/Ca2+ exchanger in mouse neurons in primary culture. Both processes required the activation of tetrodotoxin-sensitive Na+ channels. AMPA receptor activation modified the gating properties of the Na+ channel, independently of the AMPA current, suggesting a G-protein-mediated process. Indeed, co-immunoprecipitation experiments indicated that AMPA receptor activation induced the association of Gbeta with the alpha-subunit of the Na+ channel. These results suggest that, in addition to its ionic channel function, the AMPA receptor is coupled to Na+ channels through G-proteins and that this novel metabotropic function is involved in the control of neuronal excitability.

[Microdeletion of chromosome Y in male infertility: role of the DAZ gene]

Microdeletions of the Y chromosome represent the most frequent cause of male infertility, being responsible for 10-15% of cases of azoospermia or severe oligozoospermia. Such mutations localize in one or more loci named azoospermia factor (AZF) a, b and c. Mutations more frequently involve the DAZ gene in AZFc, and could determine both azoospermia and severe oligozoospermia. It is therefore difficult to find a clear relationship between genotype and phenotype. DAZ is present in multiple copies in AZFc, and this causes the gene to be difficult to analyze. In fact, polymerase chain reaction, the principal technique utilized for detection of the deletions, cannot distinguish among the different copies of the gene. Furthermore, it is not clear if all the DAZ copies are expressed in the testis, and other genes, such as CDY1, map in AZFc; therefore their alteration may play a role in determining the phenotype. In this review we report the current knowledge on the function of the Y chromosome in human spermatogenesis. In particular we analyze some of our experimental studies on the role of the DAZ gene family. Expression studies allowed us to clarify that an altered expression of DAZ might cause infertility in patients with severe testiculopathies. Furthermore, we describe for the first time a deletion not involving all the DAZ copies in a patient with severe hypospermatogenesis and we clarify that CDY1 is not involved in the testicular damage observed in patients with deletions of DAZ. These studies elucidate the role of DAZ and have important clinical consequences in the diagnostic and therapeutic approach of the infertile patient, above all when he is a candidate for assisted reproduction techniques, due to the possibility of transmitting the genetic alteration to the offspring.

Different insulin-like 3 (INSL3) gene mutations not associated with human cryptorchidism

Cryptorchidism is the most frequent congenital anomaly of the urogenital tract in the male, but its etiology is for the most part unknown. Evidence suggests that a possible genetic cause may be involved. Animal models support this hypothesis, and in particular INSL3 (Leydig insulin-like 3 hormone) has been proposed as putative gene for cryptorchidism, since male mice mutant for Insl3 exhibit bilateral abdominal cryptorchidism due to alteration of gubernaculum development. In this study, we analyzed whether mutations in INSL3 could be associated with human cryptorchidism. Heteroduplex analysis and sequencing of both exons of INSL3 in 65 ex-cryptorchid patients and a group of control subjects allowed us to find four nucleotide changes in the sequence of exon I. These mutations are all single base substitutions from G to A at position 27, 96, 126 and 178. Only the 178G-->A substitution changes codon 60 from alanine to threonine (A60T). All mutations were found in comparable distribution in ex-cryptorchid patients and non-cryptorchid men. Therefore, all mutations represent neutral polymorphisms not associated with phenotype. This study confirms previous observations and demonstrates a novel polymorphism in the INSL3 gene. In contrast to that described for the mutant mouse, these data indicate that mutations of INSL3 do not seem to represent a frequent cause of cryptorchidism.

Inhibition of protein synthesis in cortical neurons during exposure to hydrogen peroxide

Transient cerebral ischemia, which is accompanied by a sustained release of glutamate and zinc, as well as H(2)O(2) formation during the reperfusion period, strongly depresses protein synthesis. We have previously demonstrated that the glutamate-induced increase in cytosolic Ca(2+) is likely responsible for blockade of the elongation step of protein synthesis, whereas Zn(2+) preferentially inhibits the initiation step. In this study, we provide evidence indicating that H(2)O(2) and thapsigargin mobilized a common intracellular Ca(2+) pool. H(2)O(2) treatment stimulated a slow increase in intracellular Ca(2+), and precluded the effect of thapsigargin on Ca(2+) mobilization. H(2)O(2) stimulated the phosphorylation of both eIF-2alpha and eEF-2, in a time- and dose-dependent manner, suggesting that both the blockade of the elongation and of the initiation step are responsible for the H(2)O(2)-induced inhibition of protein synthesis. However, kinetic data indicated that, at least during the first 15 min of H(2)O(2) treatment, the inhibition of protein synthesis resulted mainly from the phosphorylation of eEF-2. In conclusion, H(2)O(2) inhibits protein translation in cortical neurons by a process that involves the phosphorylation of both eIF-2alpha and eEF-2 and the relative contribution of these two events depends on the duration of H(2)O(2) treatment.