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C Soler

Publications and source records attributed to C Soler.

At least 91 records · Page 5Linked to original sources
PubMed1995

Morphometric characterization of normal and abnormal human zygotes.

Human zygotes (n = 278) from 96 in-vitro fertilization gonadotrophin-stimulated cycles were photographed in their pronuclear stage (16-18 h post-insemination). Normal morphological fertilization (two pronuclei) was observed in 215 zygotes, 17 showed only one pronucleus, 40 showed three pronuclei and six showed four. Area, perimeter and maximum and minimum diameters of each zygote and pronucleus were measured using an IBAS 2000 (Kontron) image analyser. When the four groups were compared, whole zygotes did not show any morphometric difference. However, pronuclei from these groups showed that a high number of pronuclei was directly related to small pronuclei. Differences in pronuclear size and a linear increase in the nucleus/cytoplasm relationship were found which varied with the number of pronuclei.

Cell Nucleus↗
PubMed1995

[Bullous manifestations of Kaposi disease associated with AIDS].

INTRODUCTION: We report the apparently first description of bullous Kaposi's sarcoma in a patient with AIDS. CASE REPORT: Kaposi's sarcoma was observed in a HIV positive homosexual who had developed AIDS. The delay between the development of Kaposi's sarcoma and the appearance of bullae was 6 months. Bullae occurred after oedema and necrosis of the subepidermic derma. DISCUSSION: This unusual clinical presentation of Kaposi's syndrome in an AIDS patient led to rapid tumor extention and would thus suggest a rapidly unfavourable prognosis.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Study of variations of osteocalcin concentrations in function of collection, assay method and its nyctohemeral rhythm].

Osteocalcin or bone GLA protein (BGP) can be used as well as a peripheral marker of the action of hormones on osteoblast. In the present study, we report our clinical and biological results in three different conditions: the kits used for determination, the time and the hour of withdrawal. We used 4 different radioimmunoassay kits: two kits (Elsa-os-nat (cis), Osca-test (Henning)) detect intact osteocalcin molecules only and the two others (Elsa-osteo(cis), Ostk-PR(cis)) detect intact osteocalcin molecules and osteocalcin fragments. Time between collection and assay is important: we observed a diminution of osteocalcin level which can be due to the degradation of intact molecules, of 25% to 49% (depending on the kit used). The clinical profile was studied with circadian rhythm. We observed a variation of osteocalcin level in 30% of circadian rhythm according to the hour of collection sample. In conclusion, we have seen two differents situations at risk of wrong interpretation due to low level BGP: inadequate serum collection or single blood collection instead of circadian cycle.

Adult↗
PubMed1994

Improvement of attachment rate of bovine embryos after transfer with trophoblastic fragments.

Fragments of trophoblastic vesicles have been shown to improve embryo development when used in co-culture. We wished to investigate the effect of trophoblastic fragments on establishment of pregnancy after embryo transfer. Embryos (n=129) frozen by direct immersion in liquid nitrogen (Group 1), 82 embryos frozen by the slow freezing method (Group 2) and 55 fresh embryos stored at 20-22 degrees C for 21-22 h (Group 3) were transferred into recipient heifers. The embryos of each group were divided in 2 batches. Batch 1 embryos (control) were transferred without trophoblastic fragments, Batch 2 embryos of each group (experimental) were transferred in combination with frozen-thawed trophoblastic fragments at a rate of 5 to 7 fragments per embryo. The fragments were produced from 16-17 day bovine embryos frozen by vitrification. Two months following the embryo transfers it was established that the attachament rate for Batch 1 embryos in Groups 1, 2, 3 was 33%, 39% and 48%, respectively; for Batch 2 embryos in the same Groups the rate was 55%, 56% and 74%, respectively. We conclude that trophoblastic fragments promote embryo attachment, but their effect does not continue beyond the time of attachment.

Journal Article↗
PubMed1994

Effects of epidermal growth factor on gluconeogenesis and cellular redox state do not require Na+/H+ exchange or Na+/K(+)-ATPase activities.

Epidermal growth factor (EGF) triggers rapid and delayed effects on gluconeogenesis, cytosolic (lactate/pyruvate ratio) and mitochondrial (3-hydroxybutyrate/acetoacetate ratio) redox states (Soler, C. and Soley, M., Biochem. J., 294 (1993) 865-872). This study attempts to determine whether the mechanism by which EGF modulates any of these parameters is dependent on the regulation of Na+/H+ exchange and/or Na+/K(+)-ATPase activities. The Na+/H+ exchange was inhibited by either amiloride or the analogue 5-(N,N-hexamethylene)amiloride (HMA), and the Na+/K(+)-ATPase activity was inhibited by ouabain. The delayed EGF inhibition of gluconeogenesis, increase of the lactate/pyruvate ratio and decrease in the 3-hydroxybutyrate/acetoacetate ratio were unaltered in the presence of amiloride, HMA or ouabain. The rapid EGF stimulation of gluconeogenesis was also observed in the presence of HMA or ouabain. Although Na+/H+ exchange and/or Na+/K(+)-ATPase are regulated by EGF, our results indicate that these activities are not required for the effects of EGF on gluconeogenesis and/or cytosolic and mitochondrial redox state.

3-Hydroxybutyric Acid↗
PubMed1994

Individual epidermal growth factor receptor autophosphorylation sites do not stringently define association motifs for several SH2-containing proteins.

To determine whether individual autophosphorylation sites in the epidermal growth factor (EGF) receptor define specific interaction sites for the in vivo association of signal transduction proteins that contain src homology 2 (SH2) domains, the capacity of wild-type and mutant EGF receptors to associate with several SH2 domain-containing proteins has been assayed. Mutants included receptors with single autophosphorylation site mutations at each of five autophosphorylation sites and receptors in which multiple autophosphorylation sites were removed by point mutation or deletion of carboxyl-terminal residues. Receptor association, as measured by coimmunoprecipitation, has been determined for phospholipase C-gamma 1, the ras GTPase-activating protein, the p85 subunit of phosphatidylinositol 3-kinase, and the src homology and collagen protein. In contrast to data obtained with single autophosphorylation site mutants of other receptor tyrosine kinases, none of the EGF receptor single site mutants was dramatically impaired in its capacity to associate with any of these SH2-containing proteins. However, association was completely abrogated when all five autophosphorylation sites were mutated or removed by deletion. These results indicate that individual autophosphorylation sites in the EGF receptor are not stringently required for the recognition and association of different SH2-containing substrates. Thus, EGF receptor autophosphorylation sites seem to be flexible and/or compensatory in their capacity to mediate association with these four SH2-containing substrates.

3T3 Cells↗
PubMed1994

Morphometric analysis of human sperm morphology.

Fourteen morphological forms of human spermatozoa were analysed morphometrically using semi-automated image analysis techniques. Five basic (area, perimeter, length, width and mass) and five derived (ratio, length minus width, ellipticity, form and total mass) parameters were considered. Statistical analysis showed differences among all 14 types of human sperm heads. Basic parameters describing the size and shape were enough to distinguish most of the categories, whereas derived parameters as well as parameters dependent on stain intensity, were demonstrated to be useful for the discrimination of some morphological categories. The fact that statistical analysis showed differences among all 14 sperm types provides evidence for the reliability of our morphological classification. These results show that morphometry can be used for the fine study of sperm morphology and may serve as a database for future work dealing with sperm classification. As this is a pilot study to assess methodology, further studies will be required to validate the method in terms of its application and usefulness in assessing the fertilizing potential of human spermatozoa.

Humans↗
PubMed1994

Development of sperm motility patterns in the murine epididymis.

The maturation of sperm motility in the epididymis of the mouse was assessed using a computer-assisted sperm analysis system. Spermatozoa were immotile in the most proximal regions of the epididymis but developed motility rapidly in the proximal caput epididymis; the percentage motility remained high thereafter. In the caput, flagellar beat was erratic with little progression, but in the proximal corpus region circular movement patterns were reflected in reduced linearity (LIN) and straightness (STR) of the sperm tracks, although velocities were little changed and wobble (WOB) increased. In the mid-corpus region, however, all velocities, LIN, STR and WOB, increased markedly. In more distal regions there was little change in these parameters. Distribution curves of the kinematic parameters of spermatozoa obtained from each region indicated that the most heterogeneous population was that from the mid-corpus epididymis; the most homogeneous was that from the mid-cauda region. Individual sperm tracks revealed slowly progressing spermatozoa in the distal caput, transforming to motion in small circles, interrupted by more linear progression. More distally, linear progression was interrupted by looping movements and a generally progressive path was observed thereafter, with less deviation from the average path as the spermatozoa matured. Spermatozoa displaying motion compatible with passing the uterotubal junction were first found in the proximal corpus epididymis, in agreement with earlier in-vivo fertilization studies on where fertilizing capacity is achieved with epididymal spermatozoa.

Animals↗
PubMed1994

[Detection of human papillomavirus DNA by in situ hybridization and gene amplification].

In situ hybridization with non radioactive probes is attractive for human papillomaviruses (HPV) detection. Its sensitivity has been greatly improved by using different hybridization conditions, techniques for revealing the DNA-DNA hybrids and method of observation and various cell lines derived from human uterine carcinomas (CaSki, SiHa and HeLa cells) which contain 500-600 copies of HPV DNA, 1-2 copies of HPV 16 and 20-50 copies of HPV DNA 18, respectively. In situ gene amplification increased the detection of HPV DNA since hybridization spots were visible in SiHa cells on slides; a specific signal was observed in HeLa cells in suspensions examined by flow cytometry. Confocal microscopy is an alternative method to in situ gene amplification since viral DNA is detectable in SiHa cells with or without gene amplification. Thus, the techniques used in this study are potentially useful for research of single cellular genes.

Carcinoma↗
PubMed1994

Potent SHC tyrosine phosphorylation by epidermal growth factor at low receptor density or in the absence of receptor autophosphorylation sites.

The importance of epidermal growth factor (EGF) receptor expression level and autophosphorylation sites in src homology and collagen protein (SHC) tyrosine phosphorylation has been studied. In contrast to EGF-induced tyrosine phosphorylation of the GTPase-activating protein for ras (rasGAP) and phospholipase C-gamma 1 (PLC-gamma 1), SHC tyrosine phosphorylation occurs at a very low receptor density in parental NIH3T3 mouse fibroblasts expressing less than 1 x 10(4) EGF receptors per cell. In transfected NIH3T3 cells expressing human EGF receptors (approximately 4 x 10(5) receptors per cell), maximal levels of SHC and PLC-gamma 1 tyrosine phosphorylation occur when approximately 4 x 10(4) receptors or more are occupied by ligand. At lower levels of receptor occupancy only SHC phosphorylation was significant. Also, EGF treatment of mouse keratinocytes, which represent a physiological target of EGF, express a low number of EGF receptors (approximately 2 x 10(4) receptors per cell), and stringently require EGF to grow, results in intense SHC tyrosine phosphorylation, compared to rasGAP or PLC-gamma 1. SHC is also efficiently tyrosine phosphorylated by an EGF receptor deletion mutant (Dc214) that is devoid of autophosphorylation sites, but which remains mitogenically responsive to EGF. The EGF receptor mutant Dc214 is able to activate the ras guanine nucleotide exchanger and phosphorylate mitogen-activated protein kinase (MAPK), presumable as a result of complex formation between tyrosine phosphorylated SHC and GRB2. These results indicate that potent EGF-induced SHC tyrosine phosphorylation can be triggered in cells having relatively few receptors. Also, our data show that EGF receptors are able to phosphorylate SHC, activate the exchange of guanine nucleotide on ras and phosphorylate MAPK by a mechanism that does not require receptor autophosphorylation sites and, therefore, the src homology 2 (SH2):phosphotyrosine-dependent interaction of SHC or GRB2 with the EGF receptor.

3T3 Cells↗
PubMed1994

Epidermal growth factor increases protein and messenger RNA expression levels of Ras GTPase activating protein.

The Ras GTPase activating protein (RasGAP) is a key regulatory enzyme in the Ras signaling pathway, which is crucial for growth factor-induced mitogenesis. In this study, it is shown that epidermal growth factor (EGF) increases RasGAP protein expression by 100-150% in NIH 3T3 cells, which overexpress the human EGF receptor, and mouse keratinocytes but does not increase RasGAP protein expression in A431 cells, where EGF does not have a mitogenic effect. In contrast, EGF does not affect the expression of other signal transduction SH2-containing proteins, such as phospholipase C gamma 1 and the p85 subunit of phosphatidylinositide 3-kinase. The growth factor-induced increase of RasGAP protein parallels an increase in RasGAP activity. EGF stimulates RasGAP protein synthesis and does not affect its degradation rate. The mechanism for RasGAP protein induction by EGF involves an increase in rasGAP mRNA levels. The growth factor-stimulated up-regulation of rasGAP is a delayed response, since the increase in the mRNA levels and protein synthesis rate begin after 3 h and reach maximal values between 9 and 24 h of growth factor treatment. EGF fails to increase rasGAP mRNA levels in the presence of cycloheximide, suggesting that this effect is dependent on de novo protein synthesis. However, cycloheximide alone is able to increase by 6-fold rasGAP mRNA expression. Since EGF does not modify rasGAP mRNA stability, the increase in rasGAP mRNA expression is likely due to an increase in transcription of the rasGAP gene.

Animals↗
PubMed1993

Tyrosine phosphorylation of ras GTPase-activating protein does not require association with the epidermal growth factor receptor.

The importance of the carboxyl-terminal domain of the epidermal growth factor (EGF) receptor and its five autophosphorylation sites in the in vivo interaction and tyrosine phosphorylation of the ras GTPase-activating protein (rasGAP) has been investigated, using NIH 3T3 cells transfected with mutant EGF receptors. Phosphorylation of rasGAP by EGF receptor mutants, in which one to four autophosphorylation sites (Tyr-1173, -1148, -1086, and -1068) were mutated to phenylalanine, was reduced by 50-60% compared to the wild-type receptor. Elimination of these four autophosphorylation sites by truncation of 123 carboxyl-terminal residues of the EGF receptor paralleled results obtained with point mutants. Substantial inhibition (about 90%) of rasGAP tyrosine phosphorylation by the EGF receptor occurred only when the remaining autophosphorylation site (Tyr-992) was mutated, in the context of this truncated receptor or in the full-length receptor mutated at all four other autophosphorylation sites. However, a point mutation of only Tyr-992 in the full-length receptor suppressed tyrosine phosphorylation of rasGAP only by 50%. In contrast, an EGF receptor lacking the last 214 amino acid residues (Dc214), which encompasses all five autophosphorylation sites, phosphorylated rasGAP to the same extent as the wild-type receptor. However, this truncated receptor was significantly impaired in its capacity to phosphorylate phospholipase C-gamma 1. Interestingly, while EGF receptor autophosphorylation sites are required for EGF-induced rasGAP association with the receptor, maximal phosphorylation of rasGAP by the truncated receptor Dc214 occurred without detectable formation of receptor-rasGAP complexes. Furthermore, the capacity of mutated EGF receptors to bring about focal transformation was correlated with their capacity to phosphorylate rasGAP.

3T3 Cells↗
PubMed1993

Rapid and delayed effects of epidermal growth factor on gluconeogenesis.

Most reports on the effects of epidermal growth factor (EGF) on gluconeogenesis have indicated that such effects depend on the substrate used and are only observable after a lag time of 30-40 min. Recently, an immediate and transient effect of EGF on glucose synthesis was described in a perfused liver system. Here we extend the study of the effect of EGF on gluconeogenesis to isolated hepatocytes from fasted rats. The delayed effect of EGF on gluconeogenesis was studied by adding the substrate 40 min after the peptide. Under these conditions EGF increased glucose synthesis from pyruvate, decreased it when the substrate was lactate or glycerol and did not modify gluconeogensis from fructose or dihydroxyacetone. EGF did not affect the metabolic flux through glycolysis, determined as the production of lactate+pyruvate from 30 mM glucose. Furthermore, EGF did not modify the metabolic flux through pyruvate kinase, determined as the production of lactate+pyruvate from 1 mM dihydroxyacetone. The differing effects of EGF on gluconeogenesis depending on the substrate used can be explained by the effects of EGF on the cytosolic redox state (measured as the lactate/pyruvate ratio). About 20 min after the addition of EGF, the mitochondrial redox state (measured as the 3-hydroxybutyrate/acetoacetate ratio) decreased. This effect of EGF was blocked by ammonium, which also abolished the effect of the peptide on gluconeogenesis. Thus the effect of EGF at the mitochondrial level appears to be necessary for its effects on gluconeogenesis. Taken together, our results indicate that the delayed effects of EGF on gluconeogenesis are secondary to the effects of the peptide at both the mitochondrial and cytosolic levels. In addition to these delayed effects, we observed that EGF rapidly and transiently stimulated glucose synthesis from lactate, decreased the cytosolic redox state and increased oxygen consumption. All of these rapid effects required the presence of extracellular calcium and disappeared in the presence of rotenone, suggesting that this rapid effect of EGF on gluconeogenesis is secondary to the stimulation of mitochondrial respiration.

Ammonia↗
PubMed1993

Epidermal growth factor stimulates substrate-selective protein-tyrosine-phosphatase activity.

This study investigates the regulation of protein-tyrosine-phosphatase (PTPase; EC 3.1.3.48) activity by epidermal growth factor (EGF). Cytosol from EGF-treated A-431 human epidermoid carcinoma cells was used as a source of PTPase activity, and tyrosine-phosphorylated ErbB2, EGF receptor, phospholipase C-gamma 1, and the Ras GTPase-activating protein were used as substrates to monitor PTPase activity. EGF stimulated PTPase activity that was selective toward these substrates, as it dephosphorylated ErbB2 and the EGF receptor, but not phospholipase C-gamma 1 and the Ras GTPase-activating protein. EGF stimulated PTPase activity in several cell lines, regardless of EGF receptor number, and the activity was localized in the cytosol. The dephosphorylation activity in vitro was dependent on the presence of reducing agents and was inhibited by orthovanadate. Agonists such as phorbol 12-myristate 13-acetate, isoproterenol, or ATP were unable to stimulate PTPase activity. Physiological relevance is indicated by experiments showing that EGF treatment of a human mammary cancer cell line rapidly induced the dephosphorylation of ErbB2.

3T3 Cells↗
PubMed1993

Epidermal growth factor interferes with the effect of adrenaline on glucose production and on hepatic lipase secretion in rat hepatocytes.

We studied the interaction of epidermal growth factor (EGF) and adrenaline in the control of several metabolic functions in isolated hepatocytes from fed rats. EGF did not modulate glucose release, urea production or hepatic lipase secretion, but interfered with the stimulatory effect of adrenaline on both glucose and urea production and also with the inhibitory effect of this hormone on hepatic lipase secretion. EGF also interfered with the effect of both angiotensin II and vasopressin on glucose release and on hepatic lipase secretion. While the effect of EGF interfering with the action of adrenaline on glucose release was potentiated in the absence of extracellular calcium, the effect on the inhibition of hepatic lipase secretion was abolished. These results suggest that EGF interfered with catecholamine actions in the liver at a site distal from the generation of the calcium signal.

Animals↗
PubMed1993

Hyperosmolarity leads to an increase in derepressed system A activity in the renal epithelial cell line NBL-1.

Hyperosmolarity induced an increase in Na(+)-dependent L-alanine uptake in confluent monolayers of the established renal epithelial cell line NBL-1. This induction was attributable to system A and was only seen when the cells had been previously deprived of amino acids in the culture medium to derepress system A activity. It was additive to the adaptive regulation induction, and both were inhibited by cycloheximide. However, the hyperosmolarity effect was inhibited by colcemid (an inhibitor of microtubular function), but adaptive regulation was not. Otherwise, when cell monolayers were incubated in a control medium, basal Na(+)-dependent L-alanine uptake mediated by system B0 decreased. The results of this study show that: (i) system A activity was not induced by cell shrinkage and subsequent swelling due to extracellular hyperosmolarity when cells were incubated in control medium; (ii) previous expression of system A activity induced by amino acid starvation seems to be a prerequisite for further induction due to hyperosmolarity; and (iii) the effects of adaptive regulation and hyperosmotic stress are mediated by different mechanisms.

Alanine↗
PubMed1993

Expression of immune associated surface antigens of keratinocytes in human papillomavirus-derived lesions.

The expression of immune associated surface antigens of keratinocytes was studied in human papillomavirus (HPV) derived lesions in order to determine whether HPV types have a regulatory role in the pathogenesis of papillomas. A series of cutaneous and mucosal lesions were immunolabeled with monoclonal antibodies to the major histocompatibility complex class 1 (beta 2-microglobulin) and 2 (HLA-DR antigens), intercellular adhesion molecule (ICAM-1) and glycoprotein CD36 (OKM5) as well as CD1a (Langerhans cells), CD4, CD8 (T cells) and CD11a (LFA1 antigen). Testing for the presence of HPV was carried out by in situ hybridization with biotinylated probes for viral DNA detection and typing. We observed a drastic reduction or a loss of beta 2-microglobulin by keratinocytes from cutaneous lesions in correlation with the disappearance of Langerhans cells. Only mild alterations were observed in mucosal lesions. HLA-DR expressed by keratinocytes was only detected in condylomas and laryngeal papillomas and was usually associated with a dense inflammatory reaction. This HLA-DR expression may be correlated with an up-regulation of ICAM-1 and the presence of LFA1 positive leukocytes, mainly of CD8 phenotype, in the epithelium. CD36 was detected on differentiated keratinocytes of all lesions; its expression seems related to the proliferation state of the lesions and probably does not represent an immune marker. The different reactivity patterns observed in cutaneous and mucosal lesions may reflect: 1. different roles for mucosal and cutaneous HPV types in the induction of immunoregulatory surface antigens of keratinocytes, or 2. the changing nature of the cytokines released by mononuclear cells and infected keratinocytes in these lesions.

Adolescent↗