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Biomedical subjects

S Michalas

Publications and source records attributed to S Michalas.

At least 109 records · Page 6Linked to original sources
PubMed1996

The in vitro development of mouse embryos beyond the blastocyst stage into the hatching and outgrowth stage using different energy sources.

PURPOSE: The purpose of this study was to investigate the effect of male and female serum supplementation on the in vitro development of mouse embryos beyond the blastocyst stage until the outgrowth stage since the latter may be related to the nidation of the embryo. We also studied the effect of EGF addition on embryo culture and blastocyst outgrowth. METHODS AND RESULTS: The blastocyst and hatching rates of two-cell mouse embryos cultured in Ham's F-10 + BSA, Ham's F-10 + male serum, or Ham's F-10 + female serum were found to be comparable (P > 0.05). The outgrowth rate of hatched blastocysts was significantly increased, though, when they were transferred to 50% male serum compared to either 50% BSA or 50% female serum (P < 0.01 and P < 0.05, respectively). In the last experiment, either 100 or 150 ng/ml EGF was added to the culture medium from the two-cell stage till blastocyst development and the latter were cultured till outgrowth in 50% BSA, male serum, or female serum. For both concentrations of EGF, the outgrowth rate was significantly higher in male serum compared to the other conditions (P < 0.01 and P < 0.05, respectively). The outgrowth rate was also higher when EGF was used compared to plain medium before transferring the blastocysts to either male or female serum (P < 0.01 for both). CONCLUSIONS: We conclude that the development of embryos to the outgrowth stage is significantly enhanced by male serum. The addition of EGF from the two-cell stage also significantly improves the outgrowth success rate for both male and female serum conditions.

Animals↗
PubMed1996

Oocyte donation to women over 40 years of age: pregnancy complications.

Recently, oocyte donation to women of advanced age has led to a considerable number of conceptions, thus increasing the age limit for becoming pregnant. A main consideration encountered by physicians, though, is the potential medical and obstetric complications of a pregnancy at an advanced age. In this study, the obstetric complications, as well as the perinatal outcome, of pregnancies of aged recipients (above 40) are presented and compared to those of younger recipients. A significantly higher incidence of gestational diabetes (P < 0.001), an increased incidence of pre-eclampsia (at the 10% level of significance) and an increased risk for thrombophlebitis (again at the 10% level) was observed in the older patients, but a careful follow-up during their pregnancy led to a highly satisfactory obstetric and perinatal outcome. A rigorous precycle medical screening (especially for cardiovascular diseases and diabetes) and a careful follow-up during pregnancy is, therefore, imperative so that oocyte donation to older women is not withheld and continues to provide fertility possibilities to otherwise sterile patients.

Adult↗
PubMed1996

A flexible protocol for the induction of recipient endometrial cycles in an oocyte donation programme.

Synchronization of the availability of good quality oocytes from donors and adequate endometrial maturation of recipients are very important for the success of an oocyte donation programme. A flexible protocol for the endometrial preparation of recipients is important in timing embryo transfer between days 17 and 19 of the cycle ('window of receptivity'). The purpose of this study was to evaluate the effect of the length of oestradiol administration to recipients on pregnancy outcome. Oestrogen administration was 8 mg/day, but its length varied prospectively from 6 to 27 days, followed by the addition of progesterone (100 mg daily i.m.) for 2-4 days according to the availability of good quality oocytes. Pregnancy outcome was evaluated regardless of age, indication for oocyte donation or number of embryos transferred per patient. The pregnancy rate per cycle was comparable when oestradiol was administered from 6 to 11 days before progesterone addition, while it dropped significantly thereafter. The variation in progesterone administration did not affect pregnancy outcome. These findings provide us with a greater flexibility by allowing us to vary oestradiol administration to recipients from 6 to 11 days prior to progesterone, reducing considerably, therefore, the need to cancel embryo transfer because of oocyte unavailability. Thus we can arrange to transfer embryos between days 17 and 19 of the recipient's cycle so as to obtain the best possible clinical outcome.

Adult↗
PubMed1995

Uterine pinopodes as markers of the 'nidation window' in cycling women receiving exogenous oestradiol and progesterone.

In 14 cycling women participating in an in-vitro fertilization (IVF) donation programme, we examined the timing of the 'nidation window' using as a stage-specific 'marker' the presence of fully developed pinopodes on the apical surface of the luminal uterine epithelium. Each woman received exogenous oestradiol from the second day of their cycle and progesterone starting on day 8 or day 15 of the oestrogenic treatment. The women underwent two biopsies during the same artificial cycle, on either days 6 and 9 or days 8 and 10 of the progesterone treatment. All patients to whom oestradiol was administered for 7 days prior to progesterone administration (n = 9), and two of the five treated with oestradiol for 14 days prior to the addition of progesterone, showed uterine pinopodes in either one or both biopsies. When present on a given day, pinopodes were at the same stage, developing, fully developed or regressing, showing that their total lifespan did not exceed 48 h. Fully developed pinopodes existed for 1 day only which may correspond to the short period of optimal endometrial receptivity observed in animal models. The timing of the presence of fully developed pinopodes varied from patient to patient, but these individual differences were not correlated with progesterone and oestradiol plasma concentrations. The brief duration of the nidation window and the observed individual variations in its timing suggest that the detection of uterine pinopodes could be a valuable tool for the prediction, on an individual basis, of the optimal date for successful egg replacement in IVF patients.

Adult↗
PubMed1995

A preliminary study of the effect of growth hormone on mouse preimplantation embryo development in vitro.

The role of growth hormone (GH) in follicular development, ovulation and embryo development is currently under reconsideration. In this study, we have tried to investigate the effect of GH on preimplantation development of mouse embryos in vitro. Zygotes and two-cell mouse embryos were cultured without (control) or with GH. For zygotes, the addition of 0.2 micrograms/ml of GH resulted in 77 +/- 1% of blastocysts formed and 66 +/- 3% rate of hatching (control 64 +/- 4 and 31 +/- 3%, p < 0.05 and p < 0.01, respectively). For two-cell embryos, the addition of 0.2 micrograms/ml of GH resulted in 87 +/- 2% of blastocysts formed and 60 +/- 4% hatching rate (control 76 +/- 4 and 47 +/- 5%, p < 0.05 for both). This positive effect of GH addition implies that the latter can support mouse preimplantation development in vitro and it suggests, along with its local action on the ovary and its possible effects, via the insulin-like growth factor system, on the tubal and uterine epithelium, a continuous role of this hormone in reproductive physiology from follicular maturation to embryonic development and, possibly, implantation.

Animals↗
PubMed1994

High-grade endometrial stromal sarcoma in a 16-year-old girl.

Endometrial stromal sarcoma (ESS) is a rare uterine malignancy with a variety of morphologic characteristics and clinical courses. We describe a case of high-grade malignant ESS in an adolescent girl, arising in a rudimentary uterine horn and presenting symptoms of an acute abdomen. The patient underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy and omentectomy due to a stage IVA high-grade ESS. An adjuvant chemotherapy and radiotherapy treatment was recommended, but 10 days after her discharge the condition of the patient deteriorated, with diffused metastases into the lungs and the abdomen, and finally she succumbed to the disease 1 month after her first admission to the hospital.

Abdomen, Acute↗
PubMed1994

The effect of compounds altering the cAMP level on reversing the 2-cell block induced by hypoxanthine in mouse embryos in vitro.

The possibility of reversing the hypoxanthine induced 2-cell block in mouse embryos when cultured in conditions supplemented with compounds that increase (FSH, hMG, IBMX, hCG) or inhibit (GnRH-analogue) cAMP was assessed. When embryos were cultured in Ham's F-10 without hypoxanthine supplemented with each of the above compounds, no inhibition of blastocyst development was observed. Embryos were then cultured in Ham's F-10 with hypoxanthine supplemented again with each compound. For the addition of GnRH-analogue or FSH, the rate of blastocyst formation was comparable with that of the control medium with hypoxanthine alone. Instead, the addition of IBMX or hMG reversed the induced block. There was no reversible effect for the addition of 2 micrograms/ml hCG while the latter was observed with higher doses. The results from GnRH-analogue and IBMX addition show that, contrary to what was found for oocytes, stimulation of cAMP reverses the hypoxanthine-induced block in mouse embryos. FSH and hCG also had effects opposite to those observed for oocytes. It is unknown why hMG (FSH + LH) reverses the block. A lower cAMP degradation rate resulting in a higher cAMP level is a possible explanation. Our results provide further evidence that cleavage arrest by hypoxanthine has a different mechanism than the hypoxanthine-induced arrest of meiosis.

1-Methyl-3-isobutylxanthine↗
PubMed1994

Preterm delivery and low birthweight among refugees in Greece.

Recently Greece received a large number of refugees mainly from Eastern European countries, Middle East, Africa and the Pontus region. Refugee status, implying psychosocial adversities and financial problems, has traditionally been associated with unfavourable pregnancy outcome. This study aimed to compare the incidence of preterm delivery and low birthweight among 638 refugees and 1231 indigenous women giving birth at the same hospital in Athens. Conditional logistic regression was used in the analysis to account for parity and delivery date (matching variables) as well as controlling explicitly for maternal age and gender of the neonate. It was demonstrated that refugee status did not overall influence the occurrence of preterm delivery or low birthweight, thus implying that these two variables are not sensitive or early indicators of the adverse effects of psychosocial stress suffered by refugees.

Adolescent↗
PubMed1994

Ovarian tumors: prediction of the probability of malignancy by using patient's age and tumor morphologic features with a logistic model.

An attempt was made to predict the probability of malignancy of a given ovarian tumor in a certain patient by using the age and simple morphologic features of the tumor. A cohort of 959 patients with ovarian tumors was analysed retrospectively according to the patient's age and tumor characteristics such as greatest diameter, consistency, bilaterality and diagnosis as malignant (271 patients) or benign (688 patients). All variables were entered unconditionally in a logistic regression. The presence of solid/multilocular elements has a 9.6-fold increased risk of malignancy, where a bilateral tumor has a 2.8-fold increase. Significant increase in risk of malignancy was observed in ages under 20 and over 40 years, as well as in tumors with a diameter larger than 9 cm. All variables were highly significant associated with the discrimination between benign and malignant. A formula including all variables has been developed so that the probability of malignancy can be estimated by a scientific calculator. In conclusion, simple, easily determined by ultrasound and reproducible criteria such as patient's age, tumor size, consistency and bilaterality were assembled in a logistic model in order to predict the probability of malignancy for a given ovarian tumor, in an individual patient.

Adult↗
PubMed1993

A preliminary trial of human zygote culture in Ham's F-10 without hypoxanthine.

PURPOSE: This study deals with the suitability of Ham's F-10 without hypoxanthine for early cleavage-stage embryo culture. A high percentage of mouse two-cell embryos developed into morula and blastocysts in Ham's F-10 formulated without hypoxanthine (75.3 and 71.6%, respectively); in contrast, in agreement with previous reports, only 15.4% developed beyond the two-cell stage in Ham's F-10 with hypoxanthine. To begin to evaluate the effect of hypoxanthine on human embryos, a total of 318 human oocytes was fertilized and cultured in Ham's F-10 minus hypoxanthine. RESULTS: The fertilization, cleavage, and pregnancy percentages in two ovulation induction protocols [human menopausal gonadotropin (hMG)/human chorionic gonadotropin (hCG) and gonadotropin releasing hormone/hMG/hCG] were 82, 88, and 20 and 83, 91, and 30%, respectively. CONCLUSION: These results suggest that, in agreement with mouse embryo development, hypoxanthine does not appear to be necessary for human embryo cleavage and its omission from Ham's F-10 may enhance the conditions for culture of early-cleaving human embryos. These observations may lead to a better understanding of critical cell processes during early human embryonic development.

Adult↗
PubMed1993

Intracervical prostaglandin E2 gel for cervical ripening and labor induction: what is the appropriate dose?

In order to evaluate a dose-related response of cervical ripening and labor induction to a prostaglandin E2 (PGE2) gel, 110 women with uncomplicated postdate pregnancies and unripe cervices received intracervically 0.5 mg PGE2 (n = 40), 1.5 mg PGE2 (n = 35) or 2.5 mg PGE2 (n = 35). The failure rate in terms of cervical ripening was similar in all groups. Labor characteristics such as the duration of the latent phase as well as the total length of labor, the cesarean-section rate, instrumental deliveries and neonatal outcome were similar in all groups. The number of women who required oxytocin for labor augmentation was negatively correlated to the dose of PGE2 (p < 0.05). In addition, 3 out of 35 women in the 2.5-mg group presented hypertonic uterine activity. The increase in the dose of PGE2 gel did not increase the possibility for a vaginal delivery, but reduced the requirement for oxytocin while increasing hypertonic uterine action.

Administration, Intravaginal↗
PubMed1992

Pelvic surgery, reproductive factors and risk of ectopic pregnancy: a case controlled study.

A case controlled study among 361 women with surgically treated ectopic pregnancy and 420 women delivered at term was designed, aiming at characterization of the association among previous pelvic operations, selected reproductive factors and ectopic pregnancy. All types of previous pelvic operations increase the risk of ectopic pregnancy from a 2-fold increase for appendectomy to a 9-fold increase for ectopic pregnancy, if maternal age, parity, history of spontaneous and induced abortions and history of infertility is controlled. This study suggests that a previous pelvic operation may increase the risk of ectopic pregnancy.

Abortion, Induced↗
PubMed1992

Labor characteristics of uncomplicated prolonged pregnancies after induction with intracervical prostaglandin E2 gel versus intravenous oxytocin.

Labor characteristics after intracervical application of 0.5 mg prostaglandin (PG) E2 gel (n = 83) versus intravenous administration of oxytocin (n = 82) for labor induction were investigated in uncomplicated prolonged pregnancies with unripe cervix. The induction to delivery time as well as the total oxytocin dose were significantly reduced in the PGE2 group (p < 0.001). Cesarean sections, instrumental deliveries and fetal distress had the same frequency, but the failures of trial were significantly higher in the oxytocin group than in the PGE2 group (20.7 vs. 6%, p < 0.01). Twenty-four percent of women needed a second PGE2 dose, and almost half of the women in the PGE2 group experienced 'spontaneous' labor. More neonates in the oxytocin group had 5-min Apgar scores < 7 (p < 0.05). Intracervical PGE2 gel application is superior to intravenous oxytocin in terms of shortening the induction-delivery interval and increasing the frequency of successful vaginal delivery. In addition, it is safe for mother and fetus.

Administration, Intravaginal↗
PubMed1991

Combined GnRH-agonist and HMG therapy in patients with stimulation failure.

This study deals with the combined therapy of GnRH-agonist (GnRH-a) and HMG for stimulation in 15 patients who failed two prior in vitro fertilization attempts. Fifty-three patients who received HMG without GnRH-agonist suppression served as controls. Comparing the HMG group with GnRH-a/HMG cycles, the cancellation rate dropped from 35.5% to 13.2%. Oocyte recovery was similar in both groups, as were the fertilization rates, 88.4% in GnRH-a and 82% in HMG cycles, respectively. The number of embryos available for transfer was virtually identical in both groups (3.7 vs. 3.6). Embryo cleavage speed was higher in GnRH-a than in HMG regimens. The E2 rise was smooth in the GnRH-a group compared to the sharp rise observed in the HMG group. The pregnancy rate per transfer was 30.5% in the GnRH-a group versus 20.5% in the HMG group. GnRH-a seems to offer a clear improvement to a number of stimulation failures.

Adult↗
PubMed1991

Late midtrimester medical pregnancy terminations: three different procedures with prostaglandin F2 alpha and laminaria tents.

One hundred twenty eight women underwent midtrimester induced abortion with: 1) combined regimen of intramniotic prostaglandin (PG) F2a injection and intracervical laminaria tents (group A, 50 women), 2) intramniotic PGF2a injection only (group B, 51 women) and 3) laminaria tents followed by intracervical PGF2a tablets insertion (group C, 27 women). The mean induction-abortion time (+/- SE) was 24.9 +/- 1.7 hours for group A, 28.2 +/- 2.2 hours for group B (p greater than 0.05) and 42.1 +/- 3.4 hours for group C, significantly longer than goup A and B (p less than 0.001 and p less than 0.01 respectively). In 48 hours 98% of the patients of group A, 90% of group B (p less than 0.05) and 59% of group C (p less than 0.001) completed the abortion procedure. Parous women of group A and B presented similar induction - abortion time, while in nulliparous the use of laminaria shortened the abortion procedure significantly (p less than 0.05). The complications rate was low. In conclusion, the intracervical PGF2a insertion is a simple but very slow abortion procedure with high failure rates. The intramniotic PGF2a injection is a successful method for late midtrimester medical pregnancy termination and the concurrent use of laminaria tents shortens the abortion procedure, particularly in nulliparous, reduces the number of prostaglandins' reinjections and increases the incidence of successful abortion within 48 hours.

Abortion, Induced↗
PubMed1991

Expression of carcinoembryonic antigen and ferritin in normal, hyperplastic, and neoplastic endometrium.

The distribution of carcinoembryonic antigen (CEA) and ferritin was demonstrated by immunohistochemical method in 95 patients with normal, hyperplastic, and neoplastic endometrium in order to distinguish among these conditions. Fifteen patients with normal endometrium (NE), 28 with hyperplasia (AH), 12 with atypical hyperplasia (AAH), and 40 with endometrial carcinoma (CA) were studied. Paraffin section tissues were subjected to immunostaining according to the avidin-biotin complex method. CEA was found in 33% of NE cases, 46% of AH, 75% of AAH, and 83% of CA (P less than 0.01). Ferritin was not detected in any case of NE; however, it was detected in one case (4%) of AH, in one case (8%) of AAH, and in 88% of CAs (P less than 0.001). Both tumor markers exhibited a heterogeneous staining pattern, and for a given histologic hyperplastic or malignant lesion, corresponded to several phenotypes. There was no significant correlation between clinical stage or tumor grade and CEA or ferritin expression. In conclusion, ferritin seems to be a better biological marker than CEA in distinguishing between hyperplastic and neoplastic endometrial lesions and it is also more reliable than CEA for endometrial malignancy since it was absent in normal and hyperplastic endometria.

Adult↗