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1.
J Bioeth Inq ; 19(4): 571-585, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36331714

RESUMO

In vitro fertilization (IVF) involves making embryos outside of the human body, which has spurred debate about the status of the embryo, embryo research and donation. We explore couples' perceptions about embryos and their thoughts and acceptability about various disposition decisions in Norway. Based on an ethnographic study including interviews and observations in an IVF clinic, we show that couples do not perceive their pre-implantation IVF embryos to be human lives; rather, they consider successful implantation the start of life. We suggest that this response indicates a change in the perception of the human embryo or the fertilised egg from incipient life-a viewpoint that was dominant in the discussions of embryo research in the 1980s and 1990s. We also show how this view of the pre-implantation embryo elucidates why donating embryos to research appears acceptable but donating to other infertile couples seems rather difficult. Before transfer to a woman's uterus, the embryo exists in a liminality; it is not yet human life but a living cell with potential for both research and pregnancy. When an embryo is implanted and pregnancy is confirmed, human life activates; the embryo becomes potential kin, influencing couples' struggles with donating embryos to other couples.


Assuntos
Destinação do Embrião , Pesquisas com Embriões , Gravidez , Feminino , Humanos , Fertilização in vitro , Embrião de Mamíferos , Noruega
2.
Placenta ; 35(4): 249-53, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24560494

RESUMO

INTRODUCTION: Human chorionic gonadotropin (hCG) is suggested to regulate placental angiogenesis, however, its role is incompletely understood. hCG may directly stimulate angiogenesis or influence the effect of other angiogenic factors. We examined the effect of hCG and the interplay of hCG with basic fibroblast growth factor (bFGF) and with various adipokines on proliferation of vascular endothelial cells in vitro. METHODS: Human umbilical vein endothelial cells (HUVEC) were incubated for 2 days with combinations of hCG, bFGF, leptin, resistin, adiponectin, IL6 and TNFα. Incorporation of radiolabelled thymidine was used to assess cell proliferation. Immunofluorescence and flow cytometry were used to examine activation of p44/42 mitogen-activated kinase (MAPK). RESULTS: hCG induced proliferation of HUVEC alone and in combination with bFGF. Cells exposed to both hCG and bFGF displayed increased activation of p44/42 MAPK as compared to hCG or bFGF alone. Increased HUVEC proliferation was observed in the presence of increasing concentrations of leptin, resistin, adiponectin, and IL6, whereas HUVEC proliferation decreased in the presence of TNFα. hCG in combination with leptin, resistin, adiponectin or IL6 stimulated HUVEC proliferation beyond the effect of hCG alone. DISCUSSION: An interplay of hCG with adipose tissue-derived factors with angiogenic properties is plausible. Thus, maternal obesity may affect placental angiogenesis in pregnancy. CONCLUSIONS: hCG may directly stimulate angiogenesis. Also, hCG may indirectly stimulate angiogenesis through interplay with bFGF and adipokines.


Assuntos
Adipocinas/metabolismo , Gonadotropina Coriônica/metabolismo , Fator 2 de Crescimento de Fibroblastos/metabolismo , Neovascularização Fisiológica , Proliferação de Células , Células Endoteliais da Veia Umbilical Humana , Humanos , Sistema de Sinalização das MAP Quinases
3.
Reprod Biomed Online ; 23(3): 389-95, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21764382

RESUMO

Surgical eradication of minimal and mild endometriosis has been shown to increase the birth rate both spontaneously and after intrauterine insemination. This study from a reproductive medicine unit at a referral university hospital examined whether surgical eradication of minimal and mild endometriosis prior to IVF improved the treatment outcome. Records of infertile patients with minimal and mild endometriosis (American Society for Reproductive Medicine stages I and II) with no prior IVF/intracytoplasmic sperm injection (ICSI) treatments were analysed. During the first treatment cycle, women who had undergone complete removal (n=399) of endometriotic lesions experienced, compared with women with diagnostic laparoscopy only (n=262), a significantly improved implantation rate (30.9% versus 23.9%, P=0.02), pregnancy rate (40.1% versus 29.4%, P=0.004) and live-birth rate per ovum retrieval (27.7% versus 20.6%, P=0.04). Surgical removal of minimal and mild endometriotic lesions also gave shorter time to first pregnancy and a higher cumulative pregnancy rate. The study shows that women with stages I and II endometriosis undergoing IVF/ICSI have significantly shorter time to pregnancy and higher live-birth rate if all visible endometriosis is completely eliminated at the time of diagnostic surgery. Surgical elimination of minimal and mild endometriosis has been shown to increase the birth rate both spontaneously and after intrauterine insemination. In this study from a reproductive medicine unit at a referral university hospital, we examined whether surgical elimination of minimal and mild endometriosis prior to IVF improved the outcome of this treatment as well. During the first IVF treatment cycle, women who had undergone complete surgical removal of endometriosis experienced, compared with women who still had their endometriosis, an improved rate of embryo implantation, pregnancy rate and live birth rate per ovum retrieval. Surgical removal of minimal and mild endometriotic lesions also gave shorter time to first pregnancy and a higher cumulative pregnancy rate. In summary, our study shows that women with minimal and mild endometriosis undergoing IVF have shorter time to pregnancy and higher live-birth rate if all visible endometriosis is completely eliminated before the start of treatment.


Assuntos
Endometriose/cirurgia , Fertilização in vitro , Taxa de Gravidez , Injeções de Esperma Intracitoplásmicas , Adulto , Implantação do Embrião , Endometriose/complicações , Endometriose/patologia , Feminino , Humanos , Gravidez , Resultado da Gravidez , Estudos Retrospectivos , Resultado do Tratamento
4.
Hum Reprod ; 20(9): 2441-7, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15919773

RESUMO

BACKGROUND: Down-regulation with GnRH agonist has been suggested to result in a profound suppression of LH bioactivity, reduced estradiol synthesis, and thus impaired IVF and pregnancy outcome. The aims of this study were: (i) to assess the usefulness of serum LH measurement on stimulation day 1 as a predictor of ovarian response, conception and pregnancy outcome in patients treated with long-term down-regulation with GnRH agonist and recombinant FSH, and (ii) to define the best threshold LH value, if any, to discriminate between women with different outcomes of IVF. METHODS: Records of 2625 cycles in 1652 infertile women undergoing IVF (n = 1856) and/or ICSI (n = 769) treatment were reviewed. RESULTS: The range of LH concentrations on stimulation day 1 overlapped among non-conception cycles, conception cycles, ongoing pregnancies and early pregnancy losses. Receiver operating characteristic (ROC) analysis showed that serum LH concentrations on stimulation day 1 were unable to discriminate between conception and non-conception cycles (AUC(ROC) = 0.51; 95% CI: 0.49-0.54) or ongoing pregnancies versus early pregnancy loss groups (AUC(ROC) = 0.52; 95% CI: 0.47-0.57). Stratification for various low serum levels of LH did not reveal significant differences with respect to conception or pregnancy outcome among different LH levels on stimulation day 1. CONCLUSIONS: Serum LH concentration on stimulation day 1 cannot predict ovarian response, conception and pregnancy outcome in women receiving long-term down-regulation during assisted reproduction treatment.


Assuntos
Fertilização in vitro , Hormônio Foliculoestimulante/uso terapêutico , Infertilidade Feminina/sangue , Infertilidade Feminina/tratamento farmacológico , Hormônio Luteinizante/sangue , Resultado da Gravidez , Adulto , Biomarcadores/sangue , Feminino , Hormônio Liberador de Gonadotropina/agonistas , Humanos , Indução da Ovulação , Hipófise/efeitos dos fármacos , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/tratamento farmacológico , Valor Preditivo dos Testes , Gravidez , Proteínas Recombinantes/uso terapêutico , Estudos Retrospectivos , Injeções de Esperma Intracitoplásmicas
5.
Gynecol Endocrinol ; 19(4): 182-9, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15724800

RESUMO

In this study we assessed how insulin resistance affects pregnancy rates in infertile women with the polycystic ovary syndrome (PCOS) treated with laparoscopic ovarian electrocautery. Sixty-four PCOS women were included in the study in a consecutive fashion. Following the CIGMA (continuous infusion of glucose with model assessment) test, 28 women were classified as insulin resistant and 36 women as non-insulin resistant. After the ovarian electrocautery patients were observed for 12-18 months. If pregnancy did not ensue, they were referred for one or more cycles of in vitro fertilization (IVF). Following ovarian electrocautery the non-insulin-resistant women more frequently achieved a regular menstrual cycle and ovulation than the insulin-resistant PCOS women. Consequently 18 (50%) of the non-insulin-resistant PCOS women achieved a pregnancy versus only five (18%) of women in the insulin-resistant PCOS group. Following treatment with both ovarian electrocautery and IVF, 27 (75%) of the non-insulin resistant PCOS women achieved a successful pregnancy, while 13 (46%) of the insulin-resistant PCOS group achieved this. In conclusion, insulin resistance may be an important marker of a poor outcome of treatment in PCOS infertility. Further studies are needed to evaluate the possible effect of treatment alternatives to alleviate the unfavorable influences of insulin resistance and hyperinsulinemia on ovulation induction in PCOS women.


Assuntos
Eletrocoagulação , Infertilidade Feminina/cirurgia , Resistência à Insulina/fisiologia , Laparoscopia , Síndrome do Ovário Policístico/cirurgia , Adulto , Índice de Massa Corporal , Feminino , Fertilização in vitro , Hormônio Foliculoestimulante/sangue , Humanos , Infertilidade Feminina/etiologia , Insulina/sangue , Hormônio Luteinizante/sangue , Síndrome do Ovário Policístico/complicações , Gravidez , Globulina de Ligação a Hormônio Sexual/análise , Testosterona/sangue , Resultado do Tratamento
6.
Gynecol Endocrinol ; 17(3): 207-14, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12857428

RESUMO

Metformin effectively restores insulin sensitivity in insulin-resistant women with polycystic ovary syndrome (PCOS). We examined whether metformin, given prior to and during ovarian stimulation for in vitro fertilization (IVF), altered follicle stimulating hormone (FSH) requirement and increased the number of collected oocytes in these women. Seventeen insulin-resistant women with PCOS were recruited to our IVF unit to receive two consecutive cycles of ovarian stimulation with or without metformin co-treatment, the order of treatments being randomized using a table of random numbers. Metformin treatment (1500 mg/day) started 3 weeks before downregulation with buserelin acetate and was continued throughout ovarian stimulation with human recombinant FSH. Nine women completed both cycles, the results of eight women being excluded because of pregnancy after the first cycle (n = 4) or because the protocol of the study was not followed (n = 4). Mean total FSH dose was 2301 IU (range 1500-6563 IU) in metformin cycles and 2174 IU (range 1200-3900 IU) in parallel control cycles, while the mean number of collected oocytes was 8.6 (range 2-28) and 4.6 (range 1-16), respectively. Bayesian analysis showed probabilities of 0.05 that metformin reduces FSH requirement by at least 10%, and of 0.61 that at least 10% more oocytes are collected after metformin co-treatment. Co-administration of metformin is therefore likely to increase the number of oocytes collected after ovarian stimulation in insulin-resistant women with PCOS but is unlikely to reduce the requirement for FSH.


Assuntos
Fertilização in vitro , Resistência à Insulina , Metformina/uso terapêutico , Indução da Ovulação , Síndrome do Ovário Policístico/complicações , Adulto , Busserrelina/administração & dosagem , Estudos Cross-Over , Feminino , Hormônio Foliculoestimulante/administração & dosagem , Humanos , Infertilidade Feminina/etiologia , Infertilidade Feminina/terapia , Síndrome de Hiperestimulação Ovariana/epidemiologia , Proteínas Recombinantes/administração & dosagem
7.
Gynecol Endocrinol ; 16(4): 285-92, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12396557

RESUMO

We examined the impact of high leptin levels on the secretion of estradiol, inhibin A and inhibin B in obese and lean women during ovarian stimulation. Patients undergoing long-term pituitary suppression, ovarian stimulation and in vitro fertilization for non-endocrine reasons were included in this case-control study. Obese women (body mass index (BMI) > 28 kg/m(2); n = 17) were individually matched with lean women (BMI 20-25 kg/m(2); n = 17) for age and baseline follicle stimulating hormone and luteinizing hormone concentrations. Blood samples were collected in a previous menstrual cycle and 1-3 days apart throughout ovarian stimulation. Serum levels of estradiol, leptin, inhibin A and inhibin B were measured. Obese and lean women had similar serum concentrations of estradiol, inhibin A and inhibin B in the follicular and luteal phases of the spontaneous menstrual cycle, and throughout ovarian stimulation. Serum levels of leptin were higher in obese than in lean women, and increased during stimulation in both groups. In the obese group, area-under-the-curve (AUC) leptin levels correlated with AUC inhibin A levels. In the lean group, there was no correlation between AUC leptin levels and AUC levels of ovarian hormones. The results suggest that high leptin concentrations in vivo are not associated with impaired secretion of estradiol and dimeric inhibins during ovarian stimulation.


Assuntos
Estradiol/sangue , Gonadotropinas/administração & dosagem , Inibinas/sangue , Leptina/sangue , Obesidade/fisiopatologia , Indução da Ovulação , Índice de Massa Corporal , Estudos de Casos e Controles , Gonadotropina Coriônica/administração & dosagem , Feminino , Fertilização in vitro , Humanos , Menotropinas/administração & dosagem , Ciclo Menstrual
8.
Hum Reprod ; 16(12): 2587-92, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11726579

RESUMO

BACKGROUND: To elucidate possible differences between unexplained and minimal peritoneal endometriosis-associated infertility, we studied their outcome in natural cycle IVF (NIVF). METHODS: A prospective cohort study was carried out on unexplained (33 couples), minimal peritoneal endometriosis-associated (30 couples) and tubal factor (24 couples) infertility in 223 NIVF cycles, using human chorionic gonadotrophin (HCG) for ovulation induction. RESULTS: During the first NIVF attempt, follicular and luteal phase oestradiol, FSH, LH and progesterone concentrations, as well as endometrial thickness and follicular diameter were similar among the three groups. Periovulatory follicular growth monitored from day of HCG administration to oocyte aspiration was significantly lowered in unexplained infertility compared with minimal endometriosis-associated and tubal factor infertility. The fertilization rate, clinical pregnancy rate per initiated cycle, per successful oocyte retrieval and per embryo transfer, in minimal endometriosis (80.0, 10.4, 16.0 and 23.5% respectively) were similar to that in tubal factor infertility patients (68.6, 5.8, 11.4 and 16.0%) but significantly higher (P < 0.05) than that of the unexplained infertility group (62.2, 2.6, 5.4 and 8.7%). CONCLUSIONS: The significant reduction in follicular periovulatory growth, fertilization and pregnancy rates in unexplained infertility compared with minimal peritoneal endometriosis patients may be explained by sub-optimal follicular development with possibly reduced oocyte quality, intrinsic embryo quality factors or by impaired implantation. From a clinical point of view, NIVF is less suited to unexplained infertility treatment, but might represent an interesting treatment option for minimal peritoneal endometriosis-associated infertility.


Assuntos
Endometriose/complicações , Doenças das Tubas Uterinas/complicações , Fertilização in vitro/métodos , Infertilidade Feminina/etiologia , Infertilidade Feminina/terapia , Infertilidade/terapia , Adulto , Estudos de Coortes , Endometriose/patologia , Endométrio/patologia , Estradiol/sangue , Doenças das Tubas Uterinas/patologia , Feminino , Hormônio Foliculoestimulante/sangue , Fase Folicular , Humanos , Infertilidade Feminina/patologia , Fase Luteal , Hormônio Luteinizante/sangue , Masculino , Folículo Ovariano/patologia , Gravidez , Progesterona/sangue , Estudos Prospectivos , Resultado do Tratamento
10.
Gynecol Endocrinol ; 15(3): 192-7, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11447730

RESUMO

Ninety-seven women with polycystic ovary syndrome (PCOS) were tested for insulin resistance and glucose tolerance by means of the continuous infusion of glucose with model assessment (CIGMA) test. The mean concentrations of glucose and insulin at 50, 55 and 60 min of glucose infusion were interpreted using a mathematical model of glucose and insulin homeostasis, and an insulin resistance index (IR1) was obtained. Using insulin and glucose values at 60 min only, a new insulin resistance index (IR2) was obtained using the same mathematical method. In addition, fasting insulin, fasting C-peptide, fasting glucose, fasting insulin:glucose ratio and fasting C-peptide:glucose ratio were also used to assess insulin resistance. There were significant correlations between IR1 and IR2, fasting glucose, fasting insulin, fasting insulin:glucose ratio, fasting C-peptide:glucose ratio. IR2 had the highest correlation with IR1 (r = 0.97, p < 0.001) and provided the best combination of sensitivity (82.9%), specificity (93.9%), positive predictive value (91.9%) and negative predictive value (86.8%). In conclusion, the simplified CIGMA test, using insulin and glucose concentration at 60 min of glucose infusion only, is a highly sensitive and specific measure of insulin sensitivity in women with PCOS.


Assuntos
Teste de Tolerância a Glucose , Resistência à Insulina , Síndrome do Ovário Policístico/fisiopatologia , Adulto , Glicemia/análise , Peptídeo C/sangue , Jejum , Feminino , Homeostase , Humanos , Insulina/sangue , Cinética , Matemática , Modelos Biológicos , Síndrome do Ovário Policístico/complicações , Curva ROC , Sensibilidade e Especificidade
11.
Hum Reprod ; 16(6): 1086-91, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11387273

RESUMO

The impact of insulin resistance on the outcome of IVF or intracytoplasmic sperm injection (ICSI) in women with polycystic ovarian syndrome (PCOS) was examined. Insulin sensitivity was measured by the continuous infusion of glucose with model assessment (CIGMA) test. Insulin-resistant (n = 26) and non-insulin-resistant women (n = 30) with PCOS underwent a total of 100 cycles of long-term down-regulation with buserelin acetate, stimulation with human recombinant FSH, and IVF or ICSI. Blood samples were taken throughout ovarian stimulation for hormone assays. Insulin-resistant and non-insulin-resistant women had similar concentrations of FSH, LH, testosterone and androstenedione throughout stimulation, but insulin-resistant women had hyperinsulinaemia and lower sex hormone binding globulin concentrations. Insulin-resistant women also had lower oestradiol concentrations during stimulation and required higher FSH doses, but these differences disappeared after controlling for the higher body weight in the group of insulin-resistant women. Groups had similar number of oocytes collected, similar implantation and pregnancy rates, and the incidence of ovarian hyperstimulation syndrome was also similar. Obesity, independent of hyperinsulinaemia, was related to a lower oocyte count and increased FSH requirement. It is concluded that in PCOS women receiving long-term down-regulation and stimulation with recombinant FSH, insulin resistance is neither related to hormone levels nor to IVF outcome. Obesity, independent of insulin resistance, is associated with relative gonadotrophin resistance.


Assuntos
Fertilização in vitro , Resistência à Insulina , Obesidade/complicações , Síndrome do Ovário Policístico/complicações , Injeções de Esperma Intracitoplásmicas , Resultado do Tratamento , Androstenodiona/sangue , Busserrelina/administração & dosagem , Resistência a Medicamentos , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/administração & dosagem , Hormônio Foliculoestimulante/sangue , Humanos , Insulina/sangue , Hormônio Luteinizante/sangue , Obesidade/sangue , Indução da Ovulação , Síndrome do Ovário Policístico/sangue , Gravidez , Proteínas Recombinantes/administração & dosagem , Globulina de Ligação a Hormônio Sexual/análise , Testosterona/sangue
12.
Gynecol Endocrinol ; 14(5): 327-36, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11109972

RESUMO

We studied the in vitro response to insulin of granulosa-lutein cells derived from patients with polycystic ovary syndrome (PCOS) and clinically defined insulin resistance. Insulin sensitivity was assessed by continuous infusion of glucose with model assessment test (CIGMA). Insulin resistant (PCOS-IR; n = 8), noninsulin resistant (PCOS-NIR; n = 9) patients with PCOS, and women with tubal factor infertility (TF; n = 8) underwent controlled ovarian stimulation with long-term gonadotropin-releasing hormone (GnRH) agonist, recombinant follicle stimulating hormone (FSH), and in vitro fertilization. Primary cultures of granulosa-lutein cells were incubated with insulin (10, 100, 500 ng/ml) and/or luteinizing hormone (LH) (10, 100 ng/ml) in the presence of low density lipoprotein (100 micrograms/ml). The progesterone and lactate accumulation were measured in the culture medium. LH potently stimulated the progesterone secretion in all groups. Insulin alone had no effect on progesterone release in any of the groups, but stimulated lactate formation in the PCOS-NIR and TF groups. Insulin augmented the effect of LH on progesterone secretion selectively in the PCOS-NIR group. The expression of the insulin receptor was determined by Western blotting in separate cultures of granulosa-lutein cells, and showed receptor down-regulation in the PCOS-IR patients. We infer that the in vitro effect of insulin on progesterone and lactate release by granulosa-lutein cells is impaired in insulin resistant PCOS patients.


Assuntos
Corpo Lúteo/fisiologia , Células da Granulosa/fisiologia , Resistência à Insulina , Insulina/farmacologia , Hormônio Luteinizante/farmacologia , Síndrome do Ovário Policístico/fisiopatologia , Androstenodiona/sangue , Células Cultivadas , Corpo Lúteo/efeitos dos fármacos , Estradiol/sangue , Feminino , Fertilização in vitro , Hormônio Foliculoestimulante/sangue , Hormônio Foliculoestimulante/uso terapêutico , Células da Granulosa/efeitos dos fármacos , Humanos , Infertilidade Feminina/complicações , Infertilidade Feminina/fisiopatologia , Insulina/sangue , Hormônio Luteinizante/sangue , Indução da Ovulação , Progesterona/metabolismo , Receptor de Insulina/análise , Proteínas Recombinantes/uso terapêutico , Globulina de Ligação a Hormônio Sexual/análise , Testosterona/sangue
13.
Acta Obstet Gynecol Scand ; 79(1): 43-8, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10646815

RESUMO

BACKGROUND: Experience with polycystic ovary syndrome shows that insulin resistance is related to early pregnancy loss. This association was examined by comparing pregnancy outcome in obese and lean women. METHODS: A cohort of 383 patients conceiving after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) was studied. Ovarian stimulation was achieved by GnRHa and FSH or hMG (n=362), by FSH or hMG alone (n=16), or by clomiphene citrate and FSH or hMG (n=5). Luteal phase was supported with progesterone. Pregnancies were defined by >10 IU/l plasma beta-hCG on day 14. Ultrasound scan on week 6 and week 12 confirmed fetal viability. RESULTS: Lean group (body mass index [BMI]<25 kg/m2; n=304) and obese group (BMI > or =25 kg/m2; n=79) were established. Obese patients had fewer oocytes collected (median: 8 vs 10 p=0.03), they had higher abortion rate during the first 6 weeks (22% vs 12%; p=0.03) and lower live-birth rate (63% vs 75%; p=0.04). The relative risk of abortion before week 6 was 1.77 (95% CI: 1.05 to 2.97). Multivariate logistic regression analysis revealed that obesity and low oocyte count were independently associated with spontaneous abortion. In the obese group, low oocyte number was associated with a more profound increase in the risk of abortion than among lean patients. The effect of age, history of past pregnancies, or infertility diagnosis on the probability of miscarriage were not significant. CONCLUSIONS: Obesity is an independent risk factor for early pregnancy loss. This risk is, in part, related to the lower number of collected oocytes in obese women.


Assuntos
Aborto Espontâneo/etiologia , Fertilização in vitro , Obesidade/complicações , Complicações na Gravidez , Injeções de Esperma Intracitoplásmicas , Adulto , Análise de Variância , Feminino , Humanos , Modelos Logísticos , Gravidez , Fatores de Risco
14.
Scand J Clin Lab Invest ; 60(8): 649-55, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11218147

RESUMO

To investigate the clinical importance of leptin's intraovarian effects, we studied the concentration of leptin and leptin binding activity in the plasma and in the follicular fluid of PCOS patients (n=20; median BMI: 27.1 kg/m2, range 19.7-36.3) undergoing controlled ovarian stimulation with long-term GnRH agonist, recombinant FSH, and in vitro fertilization. Follicular fluid and blood samples were collected during follicle aspiration for IVF. Total leptin concentration was measured by radioimmunoassay, and specific leptin binding activity was accessed by a gel filtration column assay. Follicular fluid and plasma leptin levels were similar (median 1135 pmol/l vs. 1409 pmol/l; p=0.81). Follicular fluid to plasma leptin ratio was independently associated with cumulative FSH dose (r=0.63; p=0.006) and insulin resistance index (r=-0.45; p=0.04). Specific leptin binding activity was higher in the plasma than in the follicular fluid [median 7.94% vs. 3.49%; p<0.001]. When multivariate analysis was used to predict FSH consumption, only follicular fluid leptin levels were significantly associated with cumulative FSH dose (r=0.46; p=0.04). We infer that at least in part by increased intrafollicular leptin levels, obesity directly affects ovarian function in PCOS, and may induce a relative resistance to gonadotropin stimulation. This intraovarian effect of leptin can be even more profound because of low leptin binding activity in the preovulatory follicle of obese patients.


Assuntos
Leptina/metabolismo , Folículo Ovariano/metabolismo , Ovulação , Síndrome do Ovário Policístico/metabolismo , Adulto , Índice de Massa Corporal , Feminino , Fertilização in vitro , Hormônio Foliculoestimulante/administração & dosagem , Líquido Folicular/metabolismo , Humanos , Infertilidade Feminina/etiologia , Infertilidade Feminina/terapia , Resistência à Insulina , Leptina/análise , Síndrome do Ovário Policístico/complicações , Ligação Proteica , Proteínas Recombinantes/administração & dosagem
15.
Clin Chem Lab Med ; 37(4): 471-6, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10369120

RESUMO

The application of turbidimetric homogeneous immunoassays made the determination of several plasma components widely available. The sensitivity and accuracy of these assays are appropriate enough for routine laboratory use; however, in the case of many pathologically high concentration samples, prozone effect (high dose hook effect) can be observed, that leads to false-negative determination. Up to the present there are no cost-effective algorithms available for the safe detection of the prozone effect. Pathological serum ferritin values can be elevated up to 5000 ng/ml, while the measuring range covers only the 0-440 ng/ml range by a commercial assay. The determination of samples with ferritin concentration higher than 1500 ng/ml results in false-negative values because of the overlapping measuring range and prozone effect range. The prozone effect can be recognised by analysis of reaction kinetics after measurement. We have developed a neural network classifier system to analyse reaction kinetics of the measurements and check the prozone effect. One thousand five hundred determinations and 77 patient samples were used for neural network training and test. Using the trained neural networks, false-negative results can be filtered immediately after the determination, without re-run; thus, the sensitivity of plasma ferritin determination may become reliable enough, even in the case of high concentration samples. Applying this new technology, false-negative serum ferritin determinations can be avoided, thus even a relatively high hook effect rate (5-12% in different patient groups) can be handled safely.


Assuntos
Ferritinas/sangue , Imunoensaio/métodos , Redes Neurais de Computação , Análise Química do Sangue/métodos , Relação Dose-Resposta a Droga , Humanos , Cinética , Fatores de Tempo
16.
Orv Hetil ; 139(26): 1581-4, 1998 Jun 28.
Artigo em Húngaro | MEDLINE | ID: mdl-9676120

RESUMO

Introduction of turbidimetric homogeneous immunoassays made the determination of plasma ferritin concentration wide-ranging available. However, high-dose hook effect or prozone effect occurring at samples with high ferritin concentration can lead to false-negative results. According to the authors, this phenomenon has considerable clinical significance, in patients with iron-overload disorders false-negative laboratory values may result in inaccurate diagnosis. The prozone effect can be eliminated by reaction kinetic analysis of measurements. The authors developed a neural network classification procedure based on artificial intelligence technology for the recognition of the reactions with differing kinetic flow, and made a computer software for helping the application of the classification system. False-negative results can be filtered using this new technology following the laboratory determination, thus sensitivity of plasma ferritin determination may become safe enough even in case of high concentration samples.


Assuntos
Reações Falso-Negativas , Ferritinas/sangue , Doenças Hematológicas/sangue , Humanos , Imunoensaio , Hepatopatias/sangue , Nefelometria e Turbidimetria , Diálise Renal
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