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J Domenech

Publications and source records attributed to J Domenech.

At least 37 records · Page 2Linked to original sources

First Observation of the nu(17)-nu(4) Difference Bands of Diborane (10)B(2)H(6) and (11)B(2)H(6).

An analysis of the nu(17)-nu(4) difference bands near 800 cm(-1) of two isotopic species, (10)B(2)H(6) and (11)B(2)H(6), of diborane has been carried out using infrared spectra recorded with a resolution of ca. 0.003 cm(-1). In addition, the nu(17) band of (10)B(2)H(6) has been recorded and assigned. Since this band in (11)B(2)H(6) had already been studied (R. L. Sams, T. A. Blake, S. W. Sharpe, J.-M. Flaud, and W. J. Lafferty, J. Mol. Spectrosc. 191, 331-342 (1998)), it was possible to derive precise energy levels and Hamiltonian constants for the 4(1) vibrational states of both isotopic species. Copyright 2000 Academic Press.

Journal Article↗

Defined nuclear changes accompany the reprogramming of the microspore to embryogenesis.

The switch of the gametophytic developmental program toward pollen embryogenesis to form a haploid plant represents an important alternative for plant breeding. In the present study, the switch of the gametophytic developmental program toward a sporophytic pathway, "embryogenesis," has been studied in three different plant species, Brassica, tobacco, and pepper. The switch has been induced by stress (heat shock) at the very responsive stage of the microspore, which is the vacuolate period. As a result, the cell nucleus undergoes striking structural changes with regard to late gametophytic development, including alterations of biosynthetic activities and proliferative activity. An enrichment in HSP70 heat-shock protein and in the presence of Ntf6-MAP kinase was observed after inductive treatment in the nuclei during early embryogenesis. This apparently reflected the possible roles of these proteins, specifically the protective role of HSP70 for the nuclear machinery, and signal transduction of Ntf6-MAPK for the entry of cells into proliferation. Importantly, the observed nuclear changes were similar in the three species investigated and represented convenient markers for early monitoring of embryogenesis and selection purposes for obtaining double-haploid plants in plant breeding.

Brassica↗

Genes normally expressed in the endosperm are expressed at early stages of microspore embryogenesis in maize.

Reproduction in flowering plants is characterized by double fertilization and the resulting formation of both the zygotic embryo and the associated endosperm. In many species it is possible to experimentally deviate pollen development towards an embryogenic pathway. This developmental switch, referred to as microspore embryogenesis or androgenesis, leads to the formation of embryos similar to zygotic embryos. In a screen for genes specifically expressed during early androgenesis, two maize genes were isolated by mRNA differential display. Both genes represent new molecular markers expressed at a very young stage of androgenic embryogenesis. When their expression pattern was studied during normal reproductive development, both showed early endosperm-specific expression. Investigation of the cytological features of young androgenic embryos revealed that they present a partially coenocytic organization similar to that of early endosperm. These findings suggest that maize androgenesis may possibly involve both embryogenesis and the establishment of endosperm-like components.

Blotting, Southern↗

Absolute bioavailability and absorption profile of cyanamide in man.

A pharmacokinetic study of cyanamide, an inhibitor of aldehyde dehydrogenase (EC1.2.1.3) used as an adjuvant in the aversive therapy of chronic alcoholism, has been carried out in healthy male volunteers following intravenous and oral administration. Cyanamide plasma levels were determined by a sensitive HPLC assay, specific for cyanamide. After intravenous administration cyanamide displayed a disposition profile according to a two-compartmental open model. Elimination half-life and total plasma clearance values ranged from 42.2 to 61.3 min and from 0.0123 to 0.0190 L.kg-1.min-1, respectively. After oral administration of 0.3, 1.0, and 1.5 mg/kg x +/- SEM values of Cmax, tmax (median) and AUC were 0.18 +/- 0.03, 0.91 +/- 0.11, and 1.65 +/- 0.27 micrograms.ml-1; 13.5, 13.5, and 12 min; and 8.59 +/- 1.32, 45.39 +/- 1.62, and 77.86 +/- 17.49 micrograms.ml-1.min, respectively. Absorption was not complete and the oral bioavailability, 45.55 +/- 9.22, 70.12 +/- 4.73, and 80.78 +/- 8.19% for the 0.3, 1.0, and 1.5 mg/kg doses, respectively, increased with the dose administered. The models that consider a first-order absorption process alone (whether with a fixed or variable bioavailability value as a function of dose) or with loss of drug due to presystemic metabolism (with zero-order or Michaelis-Menten kinetics) were simultaneously fitted to plasma level data obtained following 1 mg/kg i.v. and 0.3, 1.0, and 1.5 mg/kg oral administrations. The model that best fit the data was that with a first-order absorption process plus a loss by presystemic metabolism with Michaelis-Menten kinetics, suggesting the presence of a saturable first-pass effect.

Absorption↗

A rapid single-laser flow cytometric method for discrimination of early apoptotic cells in a heterogenous cell population.

A recently reported cytometric method described the possibility of discriminating apoptotic from necrotic cells using FITC-labelled annexin V and propidium iodide (PI). Nevertheless, the brightness of PI-staining and its extensive spectral emission overlap with phycoerythrin (PE) does not permit the study of a subset of a heterogenous cell population with single laser instrumentation. The surface staining of a subset with PE in a heterogenous cell population therefore requires another exclusion dye to detect necrotic cells. We used 7-amino-actinomycin D (7-AAD) that can be excited by the 488 nm argon laser line. 7-AAD emits in the far red range of the spectrum and 7-AAD spectral emission can be separated from the emissions of FITC and PE. The fluorescence parameters allow characterization of necrotic (7-AAD+ annexin V-FITC+ cells), apoptotic (7-AAD-annexin V-FITC+ cells) and viable cells (7-AAD- annexin V-FITC- cells) in a subset of PE+ cells. The value of this method was demonstrated by measuring apoptosis and necrosis in a model of HL-60 cells exposed to different inducers of cell death. The method was validated by fluorescent cell sorting in combination with morphologic examination of the sorted cells. The technique we present is particularly valuable in a clinical setting because it enables rapid multiparameter analysis of necrosis and early apoptosis in combination with cell surface phenotyping with a single laser. We present the effects of haemopoietic growth factor deprivation on myeloid progenitor CD34+ cells as an example of its application.

Annexin A5↗

Reproducible scoring of CFU-GM and BFU-E grown in collagen-based semisolid medium after a short (3 h) training.

Colony counting remains an important source of variation in colony-forming unit-granulocyte-macrophage (CFU-GM) assays performed in methylcellulose or agar. We studied the reliability of colony scoring of CFU-GM assays carried out with collagen, a matrix that allows gel collection on glass slides and in situ cellular morphology. Fourteen slides were exchanged among laboratories, and two rounds of colony (CFU-GM and burst-forming units-erythrocyte [BFU-E]) counting were performed by 11 (first counting), then 8 (second counting) different laboratories, the majority of which had no previous experience of collagen gel cultures and reading. Two-way analysis of variance (ANOVA) of the first round of colony counting showed significant differences among centers in CFU-GM counts (p = 0.023) but not in BFU-E counts (p = 0.163). Coefficients of variation for the 14 slides ranged from 22% to 50% (median 28%) for CFU-GM counts and from 12% to 74% (median 23%) for BFU-E counts. After a 3 h session of collective colony reading attended by members of 8 laboratories, a second round of colony counting was performed. This time, ANOVA showed no significant difference among centers for CFU-GM (p = 0.533) and BFU-E (p = 0.328) counts, and coefficients of variation were significantly improved, with medians of 17% for CFU-GM counts and 20% for BFU-E counts. In addition, when data from the second round of readings were analyzed without the 2 centers counting consistently low (center 8) or consistently high (center 5), variance among centers was further improved for both CFU-GM (p = 0.798) and BFU-E (p = 0.619). In summary, this study shows for the first time that reproducible BFU-E and CFU-GM scoring can be achieved using collagen-based semisolid medium (now commercially available) as long as adequate training in colony identification is provided.

Analysis of Variance↗

Galactomannans from the cell walls of species of Paecilomyces sect. Paecilomyces and their teleomorphs as immunotaxonomic markers.

An alkali-extractable and water-soluble fraction (F1S) was obtained from cell walls of Paecilomyces variotii and species of the related genera Talaromyces, Byssochlamys and Thermoascus. The structure of the main polysaccharide of these fractions was studied and found to consist of a core of (1 --> 6)-alpha-mannopyranose partially substituted at 0.2 by chains of galactofuranose and shorter chains of mannopyranose. The differences in the regularity of the branching points and the length of the galactofuranose side chains are useful to distinguish between species. These differences were detected by immunological methods, since highly specific polyclonal antibodies were raised against these polysaccharides. Mycelium of P. variotii CBS 990.73A was stained by indirect immunofluorescence. The polysaccharides studied in this work differ from the one described for species from section Isarioidea, and this is another indication of the heterogeneity of the genus Paecilomyces.

Animals↗

Influence of the formulation on the in vitro transdermal penetration of sodium diclofenac. Evaluation of the topical and systemic anti-inflammatory activity in the rat.

A study on the transdermal permeation through human skin was performed with a series of 6 semisolid formulations (A-F) containing 1% sodium diclofenac (CAS 15307-79-6) (w/w). A commercially available drug preparation was tested as a reference. Based on permeation characteristics, a study on the topical and systemic anti-inflammatory activities of three formulations (A, F and the reference formulation) was conducted using the model of erythema induced by UV radiation in hairless rats. This is expected, together with the index of topical anti-inflammatory activity to allow the selection of the most suitable formulation for dermal application. The following representative parameters were measured in the permeation study: amount of diclofenac permeated at 24 h, flow, lag time and amount of drug retained in skin at 24 h. Of the formulations tested, diclofenac formulated in the reference formulation showed the highest values of amount of diclofenac permeated at 24 h, amount of drug retained in skin at 24 and flow. As regards the skin inflammation test, no significant differences (p < 0.05) are seen between the topical and systemic anti-inflammatory activities of the three formulations tested. However, in absolute value, formulation F shows a lower systemic activity, which would prevent potential side effects of diclofenac. Since the topical anti-inflammatory index obtained for this formulation was > 1, it is concluded that a good therapeutic performance could be obtained in the treatment of local inflammation with diclofenac by using formulation F.

Administration, Cutaneous↗

Vaccination against contagious bovine pleuropneumonia and the use of molecular tools in epidemiology.

Contagious bovine pleuropneumonia is a serious threat to cattle not only in Africa but also in southern Europe and possibly Asia. It is now present in countries that had been free of the disease for many years, giving rise to doubts about the efficiency of the control strategies. In Africa CBPP is controlled mainly by a vaccination policy that uses variant strains of Mycoplasma mycoides subsp mycoides biotype SC, called T1/44 or T1sr. Until recently, it was not possible to differentiate the various strains within the biotype and consequently to identify the vaccine strains. Restriction analysis of mycoplasma DNA with HindIII and Pst1 has been applied to 24 strains of African origin and one European strain. Each enzyme gave rise to different restriction profiles and the combination of the results permitted subdivision of these strains into 9 groups. Interestingly, some profiles of pathogenic strains seem to be restricted to certain geographical areas. The profile of the poorly immunogenic vaccinal strain KH3J is also very peculiar, and it is easily distinguished from that of the other vaccine strains originating from T1. This technique is simple once the strains are isolated. Efforts are now under way to use molecular tools based on PCR products to alleviate the difficulty of isolation.

Africa↗

All-trans-retinoic acid up-regulates CD38 but not c-Kit antigens on human marrow CD34+ cells without recruitment into cell cycle.

Retinoids, especially all-trans-retinoic acid (ATRA), are well known for their differentiating activity on HL-60 cells. Moreover ATRA induces CD38 antigen overexpression on these cells. In this study we examined the effects of ATRA on purified normal CD34+ cells from adult human marrows incubated with ATRA (1 microM) or stem cell factor (SCF) after 7 d liquid cultures in serum-deprived medium. Before and after the incubation, CD34+ cells were studied by flow cytometry to evaluate the cell-surface expression of CD38 and c-Kit antigens and the cycle status of these cells using high-resolution analysis (DNA content v Ki-67 antigen expression) to clarify the functional meaning of antigenic variations. When compared with control cultures, ATRA-treated cells displayed changes in their immunophenotypic profile. Particularly relevant was the up-regulation of CD38 antigen with a mean (+/-SEM) fold increase of 21 +/- 0.1 (P=0.028) for geometric mean fluorescence intensity (GMFI), without modulation of c-Kit expression. SCF only down-regulated expression of c-Kit with a fold decrease of 4.6 +/- 0.9 for GMFI (P=0.043). Unlike SCF, ATRA did not induce CD34+ cells to entry into cell cycle despite increased levels of surface CD38 antigen. Moreover morphological and functional assays did not argue for an ATRA-induced maturation process. Contrary to steady-state cells, CD34+ cells treated with pharmacological doses of ATRA alone displayed CD38 over-expression without change in c-Kit levels and cycle status, suggesting an absence of maturation pressure.

ADP-ribosyl Cyclase↗

Morgagni's hernia resolved by laparoscopic surgery.

Morgagni's hernias represent between 2 and 4% of the whole of nontraumatic diaphragmatic hernias in the adult, and the treatment (even with minimal symptoms) is always with surgery. We present the case of a 50-year-old woman with an oppressive, postprandial discomfort in the right side of her thorax and with increased pain when supine. The x-ray examination indicated a large portion of transverse colon inside the thoracic cavity. Once the diagnosis of Morgagni's hernia had been obtained, she was scheduled for laparoscopic surgery to reduce the hernia and to reconstruct the defect of the diaphragm using a polypropylene mesh.

Female↗

Cytokines released in vitro by stromal cells from autologous bone marrow transplant patients with lymphoid malignancy.

Marrow stromal cells of patients treated by autologous bone marrow transplantation (ABMT) for malignancies have been assessed for their ability to secrete granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor (SCF), leukemia inhibitory factor (LIF), interleukin-6 (IL-6), transforming growth factor beta1 (TGFbeta1) and macrophage inflammatory protein-1alpha. (MIP-1alpha). Long-term marrow cultures were established from 10 patients prior to and 3 months after ABMT, from 7 patients 1 yr after ABMT and from 11 controls. Cytokines in culture supernatants of stromal layers (SL) were evaluated by enzyme-linked immunosorbent assay (ELISA). Significant differences between patient groups and controls were apparent in baseline production of GM-CSF, SCF, MIP-1alpha and TGFbeta1. After IL-1beta addition in cultures, G-CSF production was reduced in pretransplant and post-transplant patients compared to controls. The production of TGFbeta1, LIF, IL-6 and more particularly SCF were reduced in post-transplant patients, while elevated levels of GM-CSF and MIP-1alpha were observed in these patients only when the values were corrected for the number of cells growing in the SL. These results indicate a prolonged stromal defect in growth factor production following ABMT for the early-stage acting cytokines IL-6, LIF and SCF as well as for G-CSF, but not for GM-CSF, while the production of the 2 inhibitors shows different pathways.

Adult↗

In vitro effect of stem cell factor on human clonogenic marrow progenitors after myeloablative treatments.

Abnormal hematopoiesis, including a deficiency of marrow progenitors and particularly of erythroid progenitors, has been described after autologous stem cell transplantation (ASCT), persisting for several years. In order to explain this deficiency, a resistance of marrow progenitors to stem cell factor (SCF) after ASCT was investigated. Marrow samples were harvested from pregraft patients at graft collection prior to ASCT, transplanted patients 6-24 months after high-dose therapy and control patients. CD34+ cells were cultured in a serum-free clonogenic assay with increasing doses of SCF. The clonogenic efficiency without SCF was lower for BFU-E in treated groups than in controls, whereas it was not different for CFU-GM. With increasing doses of SCF a dose-dependent effect was found on the numbers of both CFU-GM and BFU-E in all groups, although the maximal number of BFU-E remained lower in treated groups. However, the SCF dose that induced 50% of maximal BFU-E growth (D50) was similar in all groups. Furthermore, a dose-dependent effect on the size of BFU-E was found in all groups, with no difference in the proportion of large colonies. Thus, clonogenic erythroid progenitors from patients who have received myelotoxic treatments remain sensitive to SCF, with no evidence for a chemotherapy-related resistance.

Adult↗

Changes in the functional capacity of marrow stromal cells after autologous bone marrow transplantation.

Marrow stromal cells were evaluated several months after autologous BMT for their capacity to support both normal hemopoiesis and secrete the main growth factors involved in its control, G-CSF, GM-CSF, IL-3 and SCF. Stromal layers (SL) were obtained by long-term marrow cultures (LTMC) established from 15 patients (9 with hematologic malignancies and 6 with solid tumors) 3 months after autologous BMT and were compared to pre-graft patients. After irradiation, both post-graft and pre-graft SL were recharged with the same inoculum of normal marrow cells. As compared to pre-graft values, CFU-GM production on post-graft SL was significantly increased during the first 2 weeks of culture whereas it was decreased from week 3 to week 8. These findings were only observed in patients with hematologic malignancies and not in patients with solid tumors. Growth factor secretion was evaluated by ELISA in the supernatants of unstimulated and IL-1-stimulated SL from 10 post-graft patients, 13 pre-graft patients and 5 normal controls. In any group of patients, IL-3 was undetectable either spontaneously or after IL-1-stimulation. As compared to controls, secretion by IL-1-stimulated SL was not different for GM-CSF in pre- and post-graft patients but tended to be decreased for G-CSF in post-graft patients. SCF secretion, which was not induced by IL-1, appeared dramatically decreased in both pre- and post-graft patients. The capacity of post-graft SL to support CFU-GM growth in LTMC was correlated at week 1 with G-CSF secretion and from week 3 to week 8 with SCF secretion. These results suggest that microenvironment remains qualitatively damaged several months after BMT involving a decreased capacity both to support early hemopoiesis and to secrete SCF, particularly in patients grafted for hemopoietic malignancies.

Adult↗

Structure of complex cell wall polysaccharides isolated from Trichoderma and Hypocrea species.

The structure of fungal polysaccharides isolated from the cell wall of Trichoderma reesei, T. koningii, and Hypocrea psychrophila, have been investigated by means of chemical analyses and 1D and 2D NMR spectroscopy. The polysaccharides have an irregular structure, idealized as follows: [formula: see text] The proportions of the different side chains vary from a species to another, being n above some three times larger in H. psychrophila than in T. reesei or T. koningii.

Carbohydrate Conformation↗

Structural elucidation of acidic fungal polysaccharides isolated from the cell-wall of genera Cylindrocladium and Calonectria.

The structure of acidic fungal polysaccharides, isolated from the cell wall of Cylindrocladium and Calonectria species, has been investigated by chemical analysis, methylation and reductive cleavage analyses, and 1D and 2D 1H and 13C NMR spectroscopy. The polysaccharides have an idealized repeating unit: [formula: see text] linked to a small mannan core (< 5%), with n = 3 for Cylindrocladium penicilloides and C. quinqueseptatum and n = 5 for Calonectria theae, C. crotalariae, and C. colhounii.

Carbohydrate Sequence↗

A comparative study of the transdermal penetration of a series of nonsteroidal antiinflammatory drugs.

The transdermal absorption of a series of nonsteroidal antiinflammatory drugs (NSAIDs): indomethacin, ketoprofen, diclofenac, piroxicam, tenoxicam, ketorolac, and aceclofenac) was studied in vitro with human skin. The purpose of the study was to determine the permeation parameters (permeability rate constant, Kp; lag time, TL, and flux, J) as measures of the intrinsic transdermal permeabilities of these drugs to predict their potential for formulation in a transdermal therapeutic system (TTS). A linear correlation was established between the intrinsic log Kp values and the intrinsic partition coefficients (r = 0.863, p = 0.012, n = 7). Diclofenac had the highest value of in vitro transdermal penetration at approximately 0% ionization (Kp = 3.5 cm/h) and ketoprofen had the highest flux (J = 16 micrograms/h.cm2) of the NSAIDs assayed. Ketorolac would provide the plasma concentrations at steady state that would be nearest to the therapeutic concentration (Cr/Css = 26). Also, considering the whole permeation profile in vitro, ketorolac would be the most suitable candidate of the series studied to be formulated as a TTS.

Administration, Cutaneous↗