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C Jamin

Publications and source records attributed to C Jamin.

At least 19 recordsLinked to original sources
PubMed2003

[Antigonadotropic effects of a 19-nor-progesterone derivative: the example of nomegestrol acetate].

The antigonadotropic activity of progestins, progesterone and 19-norprogesterone derivatives, is generally used in clinical practice to treat hyperestrogenic symptoms and to provide a contraceptive effect in women with intolerance to exogenous estrogens. Our purpose was to review data from clinical pharmacological trials and from efficacy and/or safety clinical studies on progestin antigonadotropic properties with the example of nomegestrol acetate administered at the dose of 5 mg daily during 20 or 21 days per cycle. The antigonadotropic effect was shown by the effect on gonadotropins: in normally cycling premenopausal women, gonadotropin ovulatory peak was constantly inhibited, LH secretion was decreased and FSH increase at the end of the control cycle was inhibited by nomegestrol acetate (n = 5). Moreover, LH basal levels, LH response to exogenous GnRH and aeras under the curves (AUC) of LH pulsatile profile were decreased in the treated cycle (n = 11) compared to the control cycle. For both LH and FSH, the basal levels, the response to GnRH and the AUC of pulsatile profile were decreased by nomegestrol acetate compared to placebo in postmenopausal women; moreover, the frequency but not the amplitude of LH pulses was decreased. Depending on the woman's ovarian functional status, the effects of nomegestrol acetate on FSH were divergent (FSH increased before menopause and decreased at postmenopause), perhaps due to experimental conditions or a direct effect on the ovary. In postmenopausal women, the action of nomegestrol acetate on gonadotropin secretion was not modified by flutamide, a pure antiandrogen; this suggests that the antigonagotropic activity of the progestin is not mediated through the androgen receptor and it acts probably through the progesterone receptor. This antigonadotropic effect had an impact on ovarian function: in premenopausal women on nomegestrol acetate (n = 21), progesterone secretion was inhibited attesting to the absence of corpus luteum, the pre-ovulatory peak of estradiol was inhibited and plasma estradiol concentrations were decreased. The antigonadotropic activity of nomegestrol acetate results in reinforcement of its antiestrogenic activity, particurlarly on the endometrium and enables to treat the frequent clinical hyperestrogenic symptoms of the perimenopause without negative metabolic or hemostatic effects. In the efficacy and/or safety studies, no pregnancy was observed with nomegestrol acetate administered in antigonadotropic sequence, during 1355 treated cycles and the hormonal data (n = 205) were in agreement with the antigonadotropic effects of the progestin demonstrated in the clinical pharmacological studies.Furthermore, at the same dose and sequence, nomegestrol acetate, in addition to its inhibitory effect on ovulation, induces changes in the endometrium rendering it unable to implantation and in the cervical mucus to rendering it hostile to spermatozoa migration. However, it must be emphasized that data from experimental conditions required for the calculation of the Pearl Index are not available and therefore there is no legal claim for "contraception".

Adult↗
PubMed2003

[Effects of a 19-norprogesterone derivative, the fourth decade nomegestrol acetate, on lipids].

Dyslipidemia is a cardiovascular risk factor which commonly develops during forty. In Europe, progestins are frequently prescribed for treatment of perimenopausal symptoms in women in this age group, as well as in combination with estrogen replacement therapy in non hysterectomised postmenopausal women. Their complete metabolic tolerance is an important, even if non exclusive, factor to take in consideration for cardiovascular protection. Our aim was to review available data on the effects of a 19-norprogesterone derivative, nomegestrol acetate, on lipid tolerability. In healthy or at risk premenopausal women, clinical studies found no significant changes in lipid parameters (total, HDL and LDL cholesterol, triglycerides, apoprotein B, Lp(a) and LpA-I) with nomegestrol acetate administered in antigonadotropic sequence, alone or combined with estrogen in inverse sequence, during 6 to 9 cycles; there was only a small statistically significant decrease in apoprotein A1, probably due to the induced hypoestrogeny. In clinical studies carried out in postmenopausal women, nomegestrol acetate combined with estrogen replacement therapy in a sequential or continuous combined regimen, did not alter the beneficial estrogen-induced lipid profile: reductions in total and LDL cholesterol, apoprotein B and Lp(a); HDL cholesterol was unchanged and an increase in triglycerides occurred only with oral estrogens. A decrease in apoprotein A1 was found after six months of a cyclic sequential hormone replacement therapy but was associated with a beneficial increase in LpA-I. Nomegestrol acetate has proven its neutral effects on lipid metabolism and does not alter the beneficial estrogen-induced lipid effects.

Adult↗
PubMed2002

CD5-induced apoptosis of B cells in some patients with chronic lymphocytic leukemia.

Although B chronic lymphocytic leukemia (B-CLL) is characterized by prolonged survival of CD5(+) B cells in vivo, these cells apoptose spontaneously in vitro. The effect of CD5 ligation on apoptosis was studied in 27 newly diagnosed patients with B-CLL, in relation to the expression of surface IgM (sIgM), CD79b, CD38, CD72 and CD19. B cells from 15 patients (group I) were resistant to anti-CD5-induced apoptosis, whereas apoptosis above spontaneous levels was seen in the remaining 12 studied (group II). Group II was then subdivided on the basis of differences in the time required to reach maximum apoptosis: whilst B cells from seven patients underwent apoptosis by 18 h, those from the remaining five needed 36 h to apoptose. The expression of sIgM, CD5, CD79b and CD38 was higher in group II than group I, suggesting that signaling for apoptosis might operate via CD79, and that CD38 expression was required. As shown by flow cytometry and confirmed by Western blotting, apoptosis was associated with a decrease in the ratios of Bcl-2/Bax and Bcl(XL)/Bax, due to an increase in the level of Bax, but no change in that of Bcl-2. This heterogeneous apoptotic response to CD5 ligation offers an explanation for the incomplete success of anti-CD5 monoclonal therapy, and might help identify patients who would respond to such treatment.

Adolescent↗
PubMed2002

[Androgenetic alopecia].

Androgenetic alopecia (AGA) is the combined result of an androgen-dependent process and genetic transmission. These characteristics have mainly, if not exclusively, been demonstrated in men and perhaps improperly extended to women. When considering the androgen-dependent process, AGA must only be limited to the androgen receptor areas. In the scalp, these receptors have only been detected in the frontal and vertex areas but never in the temporal or the occipital areas. Male AGA exhibits these clinical features, whereas in women hair loss is rarely limited to this localization, even when large areas of hair loss often appear with age. It is now commonly accepted that male AGA is associated with an increase in 5 alpha reductase activity leading to an increase in local production of dihydrotestosterone. The mechanism by which the local dihydrotestosterone increase leads to hair follicle loss is not clearly demonstrated. Inhibition of cell proliferation in the dermal papilla and a vascular process based on the inhibition in local production of vascular endothelial growth factor (VEGF) have been proposed. The increase in 5 alpha reductase activity is genetic and depends on androgen receptor polymorphism, characterized by a decrease in the number of CAG sequences on the exon 1. Male AGA is associated with an insulin-resistant process and to a higher risk of polycystic ovary in the lineage. Therapeutically, this hormone-dependent process explains the well demonstrated efficacy of 5 alpha reductase inhibitors. In women, except in some rare cases, alopecia is diffuse and the mechanisms are different. Their origin is unknown, and probably ambiguous. Based on an association with Hashimoto's thyroiditis, an auto-immune origin could be suggested in some cases. Alopecia is unaffected by thyroid substitution. Pharmacological doses of oestrogens (pregnancy, contraception) have a beneficial effect on such alopecia, probably through different mechanisms: anti-androgen effect, increased VEGF, proliferative effect of dermal papilla cells. However, it is important to mention that the dermal papilla has an aromatase, particularly in the occipital area, the activity of which has not been assessed in female alopecia. In practice 5 alpha reductase inhibitors are ineffective in women. It is likely that the predominance observed in the frontal and vertex areas, occasionally in elderly women, is a result of the two combined disorders, the almost physiological androgen-dependent hair loss combined with diffuse loss. Pharmacological doses of oestrogens associated with anti-androgen progesterone-like agents are widely used with positive results, but not demonstrated by clinical trials.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2001

Cross-linking of human FcgammaRIIIb induces the production of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor by polymorphonuclear neutrophils.

We have reported that human autoantibodies reacting with the polymorphonuclear neutrophil (PMN)-anchored FcgammaRIIIb (CD16) protect these cells from spontaneous apoptosis. In this study, we used anti-CD16 F(ab')(2) to delineate the mechanism(s) whereby the PMN life span is extended. As documented using four methods, CD16 cross-linking impeded spontaneous apoptosis, whereas anti-CD18 F(ab')(2) exerted no effect. Incubation of PMNs with anti-CD16 prevented the up-regulation of beta(2) integrins, particularly CD11b, which is the alpha-chain of complement receptor type 3, but also CD18, which is its beta-chain, as well as CD11a and CD11c. Anti-CD16-conditioned supernatant of PMNs diminished the percentage of annexin V-binding fresh PMNs after another 18 h in culture, whereas the negative control anti-CD18 had no effect. The expression of mRNA for G-CSF and GM-CSF was induced by anti-CD16, followed by the release of G-CSF and GM-CSF in a dose-dependent manner. Anti-G-CSF and anti-GM-CSF mAbs abrogated the antiapoptotic effect of the related growth factors. The delay in apoptosis was accompanied by a down-regulated expression of Bax, and a partial reduction of caspase-3 activity. These data suggest an autocrine involvement of anti-CD16-induced survival factors in the rescue of PMNs from spontaneous apoptosis. Thus, apoptosis of aged PMNs can be modulated by signaling through FcgammaRIIIb, which may occur in patients with PMN-binding anti-FcgammaRIIIb autoantibodies.

Antibodies, Monoclonal↗
PubMed2001

Soluble Fcgamma receptor IIIb alters the function of polymorphonuclear neutrophils but extends their survival.

We have established that polymorphonuclear neutrophil (PMN)-binding anti-Fcgamma receptor IIIb (FcgammaRIIIb) autoantibodies (autoAb) inhibit the function of these cells but extend their survival. Here, we show that recombinant FcgammaRIIIb (rFcgammaRIIIb), as well as purified FcgammaRIIIb (pFcgammaRIIIb), deteriorated the PMN adherence and respiratory burst in a dose-dependent manner. Furthermore, rFcgammaRIIIb and pFcgammaRIIIb reduced the level of annexin V-binding PMN from 23.6 +/- 1.6 % to 6.3 +/- 1.0 and 11.0 +/- 1.0 %, respectively, while human serum albumin exerted no effects. Incubation of rFcgammaRIIIb with those autoAb binding to soluble FcgammaRIIIb resulted in the attachment of such immune complexes (IC) to the cells, thereby also delaying apoptosis (44.9 +/- 5.9 versus 18.0 +/- 2.0 % annexin V-binding PMN after 16 hours). Soluble FcgammaRIIIb, in concert with FcgammaRIIIb / anti-FcgammaRIIIb IC, produced similar effects in that the percentage of annexin V-binding PMN declined to 16.0 +/-1.9 %. It was thus suggested that FcgammaRIIIb / anti-FcgammaRIIIb IC inserted the Fc region of their IgG into the membrane FcgammaRIIIb. Such an interpretation is consistent with our finding that, whereas aggregated IgG and anti-FcgammaRIIIb monoclonal Ab prevented membrane FcgammaRIIIb / IC interaction, neither soluble FcgammaRIIIb, nor anti-cgammaRII did so. We conclude that the function and the life span of PMN are influenced synergistically by soluble FcgammaRIIIb and anti-FcgammaRIIIb autoAb.

Antigen-Antibody Complex↗
PubMed2001

[Evaluation of weight and morphotype of French women in gynecological consultation].

Weight and morphology change with age in proportions which depend on numerous environmental factors. This French study on 3,000 women age between 40 and 70, seeing their gynecologist, has shown that the average body mass index of this population is 23.97 kg/m2, and that the waist hip ratio is 0.81. Those two parameters increase with age and are reduced when women have a physical activity for more than 2 hours a week and are on oral contraception or hormone replacement therapy. Women on percutaneous hormone replacement therapy have a lower body mass index and a lower waist hip ratio. Cigarette smoking goes with a lower body mass index. When it dates back to more than 5 years, menopause is associated with a body mass index increase. In this population, the proportion of women under hormone replacement therapy is 69%, mostly percutaneous estrogenotherapy on a discontinuous sequential rhythm.

Administration, Cutaneous↗
PubMed2001

Functional heterogeneity of anti-endothelial cell antibodies.

While it has been claimed that some anti-endothelial cell antibodies (AECA) activate EC, there is also evidence that others trigger apoptosis. To address the issue of whether activation is a prerequisite for AECA-mediated apoptosis of EC, 23 AECA-positive sera were evaluated for their ability to induce activation and/or apoptosis. Activation was defined as an over-expression of E-selectin and intercellular adhesion molecule 1. Optical microscopy, annexin V binding, hypoploid cell enumeration, and determination of poly (ADP-ribose) polymerase cleavage-related products were used to assess apoptosis. Four functional profiles were defined: 10 sera promoted activation and apoptosis (act+/apo+), one was act+/apo-, six act-/apo+, and the remaining six act-/apo-. The reduced membrane expression of thrombomodulin was associated with apoptosis, rather than activation. Caspase-3 was implicated in the two models of apoptosis, the ratios of several survival proteins to Bax decreased, regardless of the ability of apo+ AECA to activate the cells, while radical oxygen species did not appear to be involved. Furthermore, it occurred that macrophages engulfed EC treated with apoptosis-promoting AECA, but not those incubated with AECA that did not induce apoptosis. Hence, AECA represent an extremely heterogeneous family of autoantibodies, not only because of the variety of their target antigens, but also the subsequent diversity of their effects.

Antibody Diversity↗
PubMed2001

APC resistance and third-generation oral contraceptives: Acquired resistance to activated protein C, oral contraceptives and the risk of thromboembolic disease.

Using a newly-developed technique, a severe acquired plasma resistance to activated protein C has been described in women using third-generation (rather than second-generation) oral contraceptives. The following items are discussed: (i) the technical parameters used to appreciate the effect of activated protein C induce a bias of interpretation, the mean intrinsic effect of activated protein C, in plasmas from women on second or third-generation oral contraceptives being strictly identical; (ii) there are no data available to show that this assay can indicate a thromboembolic risk in asymptomatic women on oral contraceptives; and (iii) this assay is a global and non-specific test, basically sensitive to the plasma concentrations of many coagulation factors which are increased or decreased by oestrogens and progestogens. For instance protein S, in which oral contraceptive-induced modifications account for the differential effect of oral contraceptives on Rosing's assay, but which modifications are not related to the thromboembolic risk of oral contraceptives. The androgenic potential of the progestogen may counteract the effect of oestrogens in the test. More generally, in such a complex situation in which there is a 'modification of the modification', there is no haemostasis-related test which provides a risk indicator for thrombosis. Based on testing of the plasma response to activated protein C, it is impossible to state that third-generation oral contraceptives induce a more important thromboembolic risk than oral contraceptives containing a more androgenic progestogen.

Activated Protein C Resistance↗
PubMed2001

Differential effects of anti-Fc gamma RIIIb autoantibodies on polymorphonuclear neutrophil apoptosis and function.

Anti-Fc gamma receptor IIIb (Fc gammaRIIIb) human autoantibodies (Ab) have been classified previously into three groups, based on the results of an indirect immunofluorescence (IIF) test and an enzyme-linked immunosorbent assay (ELISA): IIF+/ELISA+ (group A), IIF+/ELISA- (group B), and IIF-/ELISA+ (group C) sera. In this study, differential effects between IIF+ autoAb, recognizing cell-bound Fc gammaR, and those ELISA+, recognizing only cell-free Fc gammaR, were studied on polymorphonuclear neutrophils (PMN). Neither group A nor B autoAb was cytotoxic, although both prolonged the survival of PMN by delaying spontaneous apoptosis. By the same extent, the PMN-binding antisera stimulated the appearance of a CD11b(dim) population, following a 12-h incubation. This event was associated with a lowered expression of beta2 integrin molecules, resulting in altered PMN function. Treatment with groups A and B autoAb reduced adhesiveness and respiratory burst. This impairment of the responses was more pronounced when the cells originated from donors NA1+ NA1+ rather than donors NA2+ NA2+. From our observations, the influences of anti-Fc gammaRIIIb autoAb on PMN survival, as well as function and subsequent dysregulation of the inflammatory response, have proven somewhat dependent on their target antigens, as determined by IIF coupled with ELISA and Fc gammaRIIIb polymorphism.

Antibody-Dependent Cell Cytotoxicity↗
PubMed2000

Increased N-linked glycosylation leading to oversialylation of monomeric immunoglobulin A1 from patients with Sjögren's syndrome.

Increased serum immunoglobulin A (IgA) level is a common finding in primary Sjögren's syndrome (pSS). IgA might not be properly eliminated because of an abnormal glycosylation. We reported previously that IgA1 from patients with pSS was oversialylated. We extend this finding by showing that monomeric IgA1 contains more sialic acid (SA) in patients than in controls, as determined by enzyme-linked immunosorbent assay (ELISA) and Western blot with Sambucus nigra agglutinin (SNA), a lectin specific for SA. To localize this excess of SA on the N- and/or O-linked oligosaccharides, we analysed them separately, using N- and O-linked oligosaccharide profiling kits based on fluorophore-assisted carbohydrate electrophoresis. N-linked, but not O-linked, oligosaccharides of patients' IgA1 were oversialylated, and this seemed to be linked to an excess of SA on the same number of polysaccharides as normal IgA1. To localize the abnormality to the Fab and/or Fc fragments, monomeric IgA1 was digested with protease, separated and transferred to nitrocellulose, where SA was identified by SNA. Both Fab and Fc fragments appeared to be oversialylated. Oversialylation of N-linked oligosaccharides of IgA1 from patients with pSS might prevent the recognition of IgA by receptors that are responsible for their clearance, resulting in an excess of serum IgA and related immune complexes.

Adult↗