Humoral immune response to equine chorionic gonadotropin in ewes: association with major histocompatibility complex and interference with subsequent fertility. (65/3303)

In dairy ewes, the use of eCG as a convenient hormone for the induction of ovulation is necessary for out-of-season breeding and artificial insemination (AI). In this report we show the presence of anti-eCG antibodies in plasma of treated ewes. The major histocompatibility complex (MHC) was involved in the individual variability of the humoral immune responses to eCG. We found significant associations between the anti-eCG response phenotype and some MHC class II alleles. The low immune response phenotype was associated with one MHC class II allele only in Lacaune ewes, and the high immune response phenotype was associated with one MHC class II allele both in Manech and in Lacaune ewes. In herds, the impact of residual anti-eCG antibodies on subsequent fertility after AI seems minimal because of an indirect elimination of high-responder ewes from AI breeding. Therefore, the true magnitude of the association between residual anti-eCG antibody concentration and fertility has been underestimated. An additional experiment without any high-responder female elimination showed a significant correlation between high residual antibody concentrations and lower lambing rate after AI at a fixed time, possibly because of a delayed preovulatory LH surge. The results suggest that anti-eCG antibody concentration is one risk factor for infertility after AI.  (+info)

The influence of epitope availability on atomic-force microscope studies of antigen-antibody interactions. (66/3303)

The ability of the atomic-force microscope (AFM) to detect interaction forces between individual biological molecules has recently been demonstrated. In this study, force measurements have been obtained between AFM probes functionalized with the beta-subunit of human chorionic gonadotrophin (betahCG) and surfaces functionalized with anti-betahCG antibody. A comparison of the obtained results with previous anti-ferritin antibody-binding data identifies differences when the antigen molecule expresses only a single epitope (betahCG), rather than multiple epitopes (ferritin), for the monoclonal antibodies employed. Specifically, the probability of observing probe-sample adhesion is found to be higher when the antigen expresses multiple epitopes. However, the periodic force observed in the adhesive-force distribution, due to the rupture of single antigen-antibody interactions, is found to be larger and more clearly observed for the mono-epitopic system. Hence, these findings indicate the potential of the AFM to distinguish between multivalent and monovalent antibody-antigen interactions, and demonstrate the influence of the number of expressed epitopes upon such binding studies.  (+info)

Adjuvant L-arginine treatment for in-vitro fertilization in poor responder patients. (67/3303)

The objective of the present study was prospectively and randomly to evaluate the role of L-arginine in improving uterine and follicular Doppler flow and in improving ovarian response to gonadotrophin in poor responder women. A total of 34 patients undergoing assisted reproduction was divided in two groups according to different ovarian stimulation protocols: (i) flare-up gonadotrophin-releasing hormone analogue (GnRHa) plus elevated pure follicle stimulating hormone (pFSH) (n = 17); and (ii) flare-up GnRHa plus elevated pFSH plus oral L-arginine (n = 17). During the ovarian stimulation regimen, the patients were submitted to hormonal (oestradiol and growth hormone), ultrasonographic (follicular number and diameter, endometrial thickness) and Doppler (uterine and perifollicular arteries) evaluations. Furthermore, the plasma and follicular fluid concentrations of arginine, citrulline, nitrite/nitrate (NO2-/NO3-), and insulin-like growth factor-1 (IGF-1) were assayed. All 34 patients completed the study. In the L-arginine treated group a lower cancellation rate, an increased number of oocytes collected, and embryos transferred were observed. In the same group, increased plasma and follicular fluid concentrations of arginine, citrulline, NO2-/NO3-, and IGF-1 was observed. Significant Doppler flow improvement was obtained in the L-arginine supplemented group. Three pregnancies were registered in these patients. No pregnancies were observed in the other group. It was concluded that oral L-arginine supplementation in poor responder patients may improve ovarian response, endometrial receptivity and pregnancy rate.  (+info)

Recurrent empty follicle syndrome successfully treated with recombinant human chorionic gonadotrophin. (68/3303)

We report a case of a patient with polycystic ovary syndrome and primary infertility who was admitted to our in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programme because of her partner's severe oligozoospermia and asthenozoospermia. Ovarian stimulation was accomplished in the three treatment cycles using gonadotrophin therapy after a dual approach with ovarian suppression using oral contraceptive pills followed by gonadotrophin-releasing hormone agonist therapy. Oocyte retrieval was unsuccessful in the first two treated cycles despite the fact that human chorionic gonadotrophin (HCG) from three different batches was used. In the third treatment cycle, recombinant HCG was used and five oocytes were retrieved. This is the first report of recurrent empty follicle syndrome despite the use of different batches of commercially available urinary HCG, and of its successful treatment using recombinant HCG.  (+info)

Severe ovarian hyperstimulation syndrome following salvage of empty follicle syndrome. (69/3303)

We report a case of severe ovarian hyperstimulation syndrome (OHSS) following a rescue of empty follicle syndrome (EFS). This suggests that the risk of developing OHSS remains unaltered even in the presence of EFS. The case supports the possibility of obtaining oocytes that fertilize and cleave normally after a second dose of human chorionic gonadotrophin (HCG) and a repeat oocyte retrieval. It supports the suggestion that the follicles are not necessarily empty in EFS. It demonstrates further that OHSS cannot be prevented by aspiration of follicular fluid and patients with large numbers of follicles and EFS must be warned of this potential complication.  (+info)

Is waiting for an endogenous luteinizing hormone surge and/or administration of human chorionic gonadotrophin of benefit in intrauterine insemination? (70/3303)

This retrospective study was undertaken to investigate the observation that the probability of pregnancy was higher with intrauterine insemination (IUI) when human chorionic gonadotrophin (HCG) was administered after the onset of the luteinizing hormone (LH) surge. A total of 219 patients who had 524 IUI cycles was included in this study. IUI cycles were divided into three groups: group 1, patients who had an endogenous LH surge but no HCG; group 2, patients given HCG after an endogenous LH surge was observed; and group 3, patients given HCG before an endogenous LH surge could be demonstrated. The overall clinical pregnancy rate was 16%. Forty-two (19.2%) patients had 91 cycles with their partner's semen, while 177 (80.8%) used donor semen in 433 cycles; clinical pregnancy rates were 12.1% and 16.9% respectively. There was no significant difference in pregnancy rate per cycle between patients in group 1 (12.7%) compared with those in groups 2 (15.6%) or 3 (20.5%). We could not establish any benefit in waiting for a spontaneous LH surge before administering HCG in the presence of a mature follicle(s) in this study. This strategy avoids further monitoring to detect the LH surge, allowing treatment to be planned for a time convenient to the patient.  (+info)

125I-labelled human chorionic gonadotrophin (hCG) as an elimination marker in the evaluation of hCG decline during chemotherapy in patients with testicular cancer. (71/3303)

The rate of reduction in the concentration of serum human chorionic gonadotrophin (hCG) following chemotherapy for germ cell tumours may follow a complex pattern, with longer apparent half-life during later stages of chemotherapy, even in patients treated successfully. The commonly used half-life of less than 3 days for hCG to monitor the effect of chemotherapy in patients with germ cell tumours of the testis may represent too simple a model. 125I-labelled hCG was injected intravenously in 27 patients with germ cell tumours and elevated hCG during chemotherapy. The plasma radioactivity and hCG concentrations were followed. During chemotherapy, the plasma disappearance of hCG showed a biphasic pattern, with an initial fast and a later slow component in all patients. Using the steep part of the hCG plasma disappearance curve, five patients who achieved long-term remission had half-lives longer than 3 days (3.6-6.8 days), whereas four out of five patients not achieving long-term remission had half-lives shorter than 3 days. After the third treatment cycle, eight patients who achieved long-term remission had hCG half-lives longer than 3 days (7.4-17.0 days). In these patients, the plasma disappearance of [125I]hCG was equivalent to that of hCG. Thus, the slow decline of hCG represented a slow plasma disappearance rather than a hCG production from vital tumour cells and could, consequently, not be used to select patients for additional or intensified chemotherapy. The concept of a fixed half-life for plasma hCG during treatment of hCG-producing germ cell tumours is inappropriate and should be revised. Difficulties in interpreting a slow decline of hCG may be overcome by comparing the plasma disappearance of total hCG with the plasma disappearance of [125I]hCG.  (+info)

Validation of 125I-hCG as a marker for elimination of hCG and stability of 125I-hCG after in vivo injection in humans. (72/3303)

We have recently introduced 125I-hCG as an elimination marker in patients with human chorionic gonadotrophin (hCG) producing testicular cancer. 125I-hCG is a well-known reagent in clinical biochemistry and is used extensively in hCG assays. Previous studies have shown that the iodination process leaves the hCG molecule mainly intact. The iodination, purification and stability of 125I-hCG tracer are described. The aim of the present study was to determine whether or not 125I is associated with hCG after the injection of 125I-hCG intravenously (i.v.) in humans. Three different methods were used. Following injection of 125I-hCG, the plasma disappearance of radioactivity and hCG were followed for a period of 28 days in 13 normal subjects. Serum from a normal healthy male following injection of 125I-hCG was analysed using a double antibody direct binding radioimmunoassay specific for holo-hCG and high performance liquid chromatography (HPLC). Following injection of 125I-hCG in eight normal healthy males and five normal healthy females, the disappearance of radioactivity and hCG showed identical paths in the 28 days follow-up period. The bindable radioactive fraction of immunologically active hCG in serum of a normal healthy male following injection of 125I-hCG was between 57.0% and 72.1%, and was constant over time. HPLC showed similar elution pattern of serum from a normal healthy male injected i.v. with 125I-hCG and 125I-hCG. Using three different methods, we were able concurrently to demonstrate the association of 125I with hCG in humans up to 28 days after injection of radiolabelled hCG i.v. Thus, information about the expected elimination of hCG can be obtained by following the elimination of activity in plasma after injection of 125I-hCG.  (+info)