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Biomedical subjects

G E Hofmann

Publications and source records attributed to G E Hofmann.

At least 19 recordsLinked to original sources
PubMed1992

Epidermal growth factor and its receptor in human implantation trophoblast: immunohistochemical evidence for autocrine/paracrine function.

Epidermal growth factor (EGF) and its receptor (EGF-R) were immunohistochemically localized in trophoblast during human implantation from intrauterine and ectopic pregnancies. EGF immunostaining was absent to light in the cytotrophoblast (CT), light to moderate in intermediate trophoblast (IT), and intense in the syncytiotrophoblast (ST). In ST, EGF immunostaining was found mostly in the cytoplasm; however, staining of the plasma membrane was also noted. Immunostaining for the EGF-R was absent to light in the CT and moderate to intense in the IT. Immunostaining for the EGF-R was intense in the ST, with moderate staining in the cytoplasm and intense staining in the plasma membrane. Staining was most intense on the microvilli of the ST. Additionally, EGF-R immunostaining could be demonstrated on nuclear membranes. The increase in the intensity of the immunostaining for both EGF and EGF-R noted in CT, IT, and ST suggests a differentiated expression of this receptor-ligand system in human trophoblast and provides evidence for an autocrine/paracrine role for EGF in trophoblast function. The presence of this receptor-ligand system during early human implantation strongly supports a role for EGF and the EGF-R in embryo-uterine signalling and the implantation process.

Embryo Implantation↗
PubMed1992

Comparison of messenger RNA pools in active and dormant Artemia franciscana embryos: evidence for translational control.

In response to environmental anoxia, embryos of the brine shrimp Artemia franciscana enter a dormant state during which energy metabolism and development are arrested. The intracellular acidification that correlates with this transition into anaerobic dormancy has been linked to the inhibition of protein synthesis in quiescent embryos. In this study, we have addressed the level of control at which a mechanism mediated by intracellular pH might operate to arrest protein synthesis. Two independent lines of evidence suggest that there is an element of translational control when protein synthesis is arrested in dormant embryos. First, as determined by in vitro translation techniques, there were no significant quantitative differences in mRNA pools in dormant as compared to actively developing embryos. In addition, fluorography of the translation products showed that there are no large qualitative changes in mRNA species when embryos become dormant. These data suggest that there was no net degradation of mRNA pools in dormant embryos and that protein synthesis may therefore be controlled more strongly at translation than at transcription. Second, polysome profile studies showed that dormant embryos possess reduced levels of polysomes relative to those found in cells or active embryos. The disaggregation of polysomes is an indication that the initiation step in protein synthesis is disrupted and is further evidence that the mechanism involved in protein synthesis arrest in dormant Artemia involves translational control.

Animals↗
PubMed1991

Immunohistochemical localization of gonadotropin-releasing hormone during implantation in the New Zealand white rabbit.

Gonadotropin-releasing hormone was localized immunohistochemically during implantation (gestational days 6 to 14) in the New Zealand White rabbit. During early implantation (days 7 to 9), intense gonadotropin-releasing hormone immunostaining was localized predominantly to the cytoplasm of the nonknob cytotrophoblast with light to moderate staining in the cytoplasm of the syncytiotrophoblast (knob). In later gestation, light to moderate staining of the cytoplasm of the trophoblast at the true placental site was detected. No appreciable change in staining was noted after day 10. Fetal membranes, identified after day 10, showed intense and unchanging immunostaining for gonadotropin-releasing hormone. Obplacental giant cells showed light to moderate nuclear and cytoplasmic gonadotropin-releasing hormone immunostaining. Light to moderate gonadotropin-releasing hormone immunostaining was also noted in the cytoplasm of uterine epithelium and glands. We conclude that immunoreactive gonadotropin-releasing hormone is present in the cytotrophoblast at the time of the earliest embryo-uterine interactions and may play a significant role in implantation and embryo survival.

Animals↗
PubMed1991

An insight into early reproductive processes through the in vivo model of ovum donation.

To gain insight into early reproductive processes we have prospectively designed ovum donation protocols to elucidate several phenomena relating to embryo implantation and pregnancy sustenance. Artificial endometrial cycles with variable follicular phases were induced in 60 recipients by sequential estrogen and progesterone. A total of 964 oocytes were retrieved throughout 43 ovum donation attempts, for an average of 22.4 (range, 16-41) eggs/retrieval. The overall delivery rate per egg retrieval (donors and recipients combined) was 72.1% (31 of 43). The shortest estrogen stimulation (short follicular phase) resulting in ongoing pregnancies was 5 days in duration, while the longest (long follicular phase) was 35 days in duration before progesterone initiation. Utilization of variable length follicular phases, artificially extended the stage of endometrial receptivity to over 4 weeks. To assess the window of implantation, same age embryos were transferred onto endometrium of different maturational stages. Pregnancies were documented with embryo transfers between luteal day 1 (day 15) to luteal day 6 (day 20), extending the window of implantation in the human to at least 6 consecutive days. To evaluate the relative contribution of oocyte quality and endometrial receptivity to pregnancy outcome, common source ova were transferred onto endometrium with variable hormonal exposure. Despite the drastically different follicular phase estradiol levels and periods of exposure, similar delivery rates were attained in donor cycles (29.4%) and recipient cycles during short follicular phases (29.6%). Slightly higher delivery rates (39.4%) were observed with long follicular phases. The comparable pregnancy rates in donors and recipients are attributed to the common source oocytes regardless of endometrial stimulation.

Adult↗
PubMed1991

Immunohistochemical localization of epidermal growth factor in human endometrium, decidua, and placenta.

Epidermal growth factor (EGF) was localized immunohistochemically in human endometrium throughout the menstrual cycle, in gestational decidua, and in first, second, and third trimester placenta using two polyclonal antihuman EGF antisera. In proliferative phase endometrium, moderate EGF immunostaining was localized to the cytoplasm of stromal cells, with absent to light staining of glandular epithelium. In the secretory phase, EGF immunostaining was intense and localized predominantly to stromal cells, particularly those surrounding spiral arterioles. There was absent to light EGF immunostaining within epithelial cells; however, there was no staining of subnuclear vacuoles. In addition, the luminal surface of exhausted secretory glands demonstrated moderate EGF immunostaining. In gestational decidua, EGF immunostaining was light to moderate in the stromal cells, but was intense in the surface epithelium. Intense EGF immunostaining was noted in the syncytiotrophoblast layer of first trimester placenta, with light to moderate staining of the cytotrophoblast. Immunostaining decreased in both layers of trophoblast as pregnancy progressed. Immunoreactive EGF is found in endometrium and trophoblast and may have a physiological role in endometrial and placental function.

Decidua↗
PubMed1990

Immunohistochemical localization of epidermal growth factor receptor during implantation in the rabbit.

Epidermal growth factor receptor was localized immunohistochemically during implantation (gestational days 7 through 14) in the rabbit. During early implantation (days 7 through 9), immunostaining was observed in the cytoplasm and on the surface of the syncytiotrophoblastic knobs. By day 8, immunoreactivity was most pronounced in knobs interacting directly with uterine epithelium but was noted in nonknob cytotrophoblast as well. Fetal membranes, identified by day 10, were stained intensely on all days examined. In later gestation the trophoblast was stained intensely on the surface and in the cytoplasm, with some staining over nuclei. No appreciable changes in the staining pattern were observed after day 10. Uterine epithelium demonstrated epidermal growth factor receptor staining first on the antimesometrial (day 7) and then the paraplacental epidermal (day 9). After day 10, most staining was at the embryo-maternal interphase. These data suggest that the embryo and uterine epithelia can receive signals from their environment during and after implantation through the epidermal growth factor receptor.

Animals↗
PubMed1990

Gonadotropin stimulation for in vitro fertilization and embryo transfer in insulin-dependent diabetics: follicular response, oocyte quality, embryo development, and follicular environment.

Two IDD patients were stimulated with gonadotropins for IVF and ET. Both patients had high E2 response and greater than or equal to 5 preovulatory oocytes retrieved, normal fertilization and cleavage rates, and transfer; neither conceived. Follicular fluid showed levels of E2, P, A, hCG, and PRL similar to non-IDD. Epidermal growth factor could not be detected in FF. Insulin-dependent diabetes patients can undergo gonadotropin stimulation for IVF with customary responses. Their follicular milieu resembles that of non-IDD patients except for a lack of EGF.

Adult↗
PubMed1990

Intercycle variability of day 3 follicle-stimulating hormone levels and its effect on stimulation quality in in vitro fertilization.

Prior studies have demonstrated that gonadotropin stimulation quality and pregnancy rates are better in in vitro fertilization (IVF) patients with low basal cycle day 3 follicle-stimulating hormone (FSH) levels. The records of 81 patients who had undergone three or more IVF attempts during a 2-year period were studied to determine the degree and potential impact of intercycle variability in basal FSH concentrations. The mean of the individual standard deviations for all 81 patients was 4.2 +/- 0.4 mIU/mL. However, the patients with a mean basal FSH of less than 15 mIU/mL had a mean deviation of only 2.6 +/- 0.2 mIU/mL, whereas those with a mean basal FSH of greater than or equal to 15 mIU/mL had a mean deviation of 7.3 +/- 0.7 mIU/mL. Intercycle variability in basal FSH values did not predict changes in ovarian response to gonadotropin stimulation and thus may not be used to select an optimal cycle in which to stimulate an individual patient. Furthermore, patients with large intercycle variation responded poorly to gonadotropin stimulation independent of their basal FSH concentration. This information allows more precise counseling of patients regarding their appropriateness for assisted reproduction.

Animals↗
PubMed1990

Effects of leuprolide acetate on follicular fluid hormone composition at oocyte retrieval for in vitro fertilization.

The follicular fluid (FF) in 91 follicles from 17 women treated with leuprolide acetate (LA) before stimulation with gonadotropins for in vitro fertilization were analyzed for estradiol (E2), progesterone (P), androstenedione, prolactin, and human chorionic gonadotropin (hCG) and compared with the concentrations in 128 follicles from 31 women treated with gonadotropins alone. The FF E2 concentration in LA-treated patients was significantly lower than in non-LA patients for all oocyte maturational stages. Follicles containing metaphase II oocytes had significantly lower concentrations of P and hCG in LA-treated patients. These differences persisted when analysis was limited to follicles whose oocytes fertilized normally. These data indicate that in the presence of LA, normal oocyte maturation can occur despite lower intrafollicular concentrations of E2 and P.

Adult↗
PubMed1990

Arrest of cytochrome-c oxidase synthesis coordinated with catabolic arrest in dormant Artemia embryos.

We have examined cytochrome-c oxidase (COX) biosynthesis in brine shrimp (Artemia franciscana) embryos during preemergence development (PED), as well as its inhibition under anaerobic dormancy, to determine whether transitions in intracellular pH (pHi) have a regulatory influence on anabolic processes. Under control aerobic conditions (embryo pHi greater than or equal to 7.9), incorporation of radiolabeled amino acids shows that substantial biosynthesis of COX occurs during 12 h of PED (500% increase when corrected for enzyme turnover). This anabolic process is blocked under anoxia, a condition known to foster intracellular acidification (pHi less than or equal to 6.8). The arrest of COX synthesis is quantitatively identical when embryos are incubated aerobically during artifical acidification with CO2 (pHi = 6.8). The data suggest that pHi, directly or indirectly, is a regulator of protein synthesis in Artemia embryos during anaerobic dormancy. Previous work has established a fundamental role for pHi in the arrest of carbohydrate catabolism under anoxia. Thus there appears to be a coordinated suppression of energy-producing and energy-utilizing events as Artemia embryos enter quiescence that involves pHi as the common intracellular signal.

Acids↗
PubMed1990

Epidermal growth factor (EGF) concentrations in amniotic fluid and maternal urine during pregnancy.

Epidermal growth factor (EGF) was measured in amniotic fluid and maternal urine from women undergoing amniocentesis for genetic studies (15-22 weeks' gestation, n = 36) and lung maturational studies (35-39 weeks' gestation, n = 20). Amniotic fluid EGF concentrations (mean +/- SD) were higher near term (87 +/- 71 pM) than mid-gestation (35 +/- 8 pM) (p less than 0.0001). Urinary EGF concentrations were higher near mid-gestation (53.9 +/- 30.8 micrograms EGF/g creatinine) than near term (33.4 +/- 14.1 micrograms EGF/g creatinine) (p less than 0.006). There was no correlation between individual amniotic fluid and urinary EGF concentrations. The amniotic fluid EGF concentrations correlated with gestational age. However, there was no relationship between EGF concentrations and pulmonary maturity studies or placental weight from the pregnancies studied near term. We conclude that the concentration of EGF in amniotic fluid increases towards term. The lack of correlation between amniotic fluid and maternal urinary EGF concentrations suggests that there probably is a different source of EGF in the two compartments and that EGF does not cross the placenta to any great extent.

Amniocentesis↗
PubMed1990

Immunoreactive epidermal growth factor concentrations in follicular fluid obtained from in vitro fertilization.

Immunoreactive epidermal growth factor (EGF) was measured in follicular fluid (FF) obtained at the time of oocyte retrieval for in vitro fertilization from cycles with (91 follicles) and without (128 follicles) the gonadotropin-releasing hormone agonist leuprolide acetate (LA). Follicular fluid immunoreactive EGF levels in the non-LA cycles correlated with androstenedione but not estradiol or progesterone levels from follicles with prophase I oocytes or from all follicles taken together, but not from metaphase I or metaphase II oocyte containing follicles alone. In non-LA cycles, FF immunoreactive EGF levels were lower in follicles that contained metaphase I or II oocytes than prophase I oocytes. Additionally, FF immunoreactive EGF levels were lower in follicles containing metaphase I or II oocytes from non-LA than LA cycles. We conclude that immunoreactive EGF is present in FF. Leuprolide acetate may affect FF immunoreactive EGF levels.

Androstenedione↗
PubMed1989

Correlation of follicular diameter with oocyte recovery and maturity at the time of transvaginal follicular aspiration.

Forty-four consecutive patients undergoing transvaginal follicular aspiration for in vitro fertilization underwent ultrasonic measurement of follicular diameter at the time of oocyte retrieval to determine the correlation of follicular size with recovery rates and oocyte maturity. Based on the results of 412 follicles aspirated, the data were grouped by size (less than or equal to 11, 12-14, 15-17, 18-20, and greater than or equal to 21 mm) and oocyte maturity. Recovery rates were significantly higher in 18- to 20-mm follicles (P less than 0.01) and lower in those less than or equal to 11 mm (P less than 0.001). The probability of retrieving a metaphase I or II oocyte was significantly lower in follicles less than or equal to 11 mm (P less than 0.001), somewhat higher in 12- to 14-mm follicles (P less than 0.01), and equally high among the other groups. There were no differences in the incidence of fractured zonas. We conclude that follicles greater than or equal to 15 mm provide the highest probability of retrieving mature oocytes and the low recovery rates of mature oocytes from follicles less than or equal to 11 mm suggest that, in selected circumstances, the operating surgeon may choose not to aspirate them.

Cell Cycle↗
PubMed1989

A prospective randomized comparison of single- and double-lumen needles for transvaginal follicular aspiration.

Patients undergoing ultrasound-directed transvaginal follicular aspiration in a large in vitro fertilization (IVF) program were randomized for retrieval with either a single-lumen needle (SLN; N = 22) or a double-lumen needle (DLN; N = 22) to compare recovery rates and the technical aspects of their use. Two hundred ten and two hundred two follicles were aspirated with each needle, respectively. Follicular diameters were measured ultrasonically at the time of aspiration and recorded. One or more washes were performed when using the DLN and the SLN was withdrawn each time to recover the fluid in the dead space of the needle. The distribution of follicular sizes was the same for both needles. Oocyte recovery rates (SLN = 65.7%; DLN = 63.9%) and the incidence of fractured zonae (SLN = 9.1%; DLN = 6.4%) were the same for both needles (alpha greater than 0.50; beta less than 0.01). Although there were no differences between the two needles in the number of oocytes provided for IVF, there were technical differences. The DLN needle was more flexible and frequently deviated from the projected path as observed by ultrasound. The SLN may be preferable because it is technically easier to use; however, there may remain specific indications for the use of the DLN.

Evaluation Studies as Topic↗
PubMed1989

High-dose follicle-stimulating hormone (FSH) ovarian stimulation in low-responder patients for in vitro fertilization.

Follicle-stimulating hormone (FSH) was used in high doses (6 ampoules/day:6FSH) for ovarian hyperstimulation for in vitro fertilization in women with a previous poor response to stimulation with the equivalent of "4FSH." Luteinizing hormone levels did not differ between stimulations, but both FSH and estradiol levels were higher in the 6FSH compared to the 4FSH cycle. There were fewer cancellations in the 6FSH cycle, but similar numbers of preovulatory oocytes were retrieved, fertilized, and transferred. The pregnancy rates per attempt and retrieval were higher in the 6FSH cycle. We conclude that raising and maintaining FSH levels during stimulation in low responders reduced cancellations and may improve in vitro fertilization outcome.

Adult↗
PubMed1989

The incidence of transient hyperprolactinemia in gonadotropin-stimulated cycles for in vitro fertilization and its effect on pregnancy outcome.

The incidence of transient hyperprolactinemia and its impact on in vitro fertilization (IVF) were determined in 151 euprolactinemic women with tubal infertility undergoing an identical gonadotropin stimulation for IVF. Prolactin (PRL) levels were measured on the morning of cycle day 3, days of human chorionic gonadotropin (hCG) administration, and peak estradiol (E2), and in the midluteal phase. Women were divided into high (H: peak E2 greater than 1,000 pg/mL, n = 51), intermediate (I:peak E2: 500 to 800 pg/mL, n = 50), or low (L:peak E2 less than 400 pg/mL, n = 50) E2 response groups. There was no difference in the incidence of hyperprolactinemia on cycle day 3 between the response groups (H:16%, I: 12%, and L:8%). However, high responders had a higher incidence of hyperprolactinemia than intermediate or low responders on all other study days. The incidence of hyperprolactinemia was greater than baseline (cycle day 3) only in the high responders on the day of peak E2. Serum prolactin was strongly correlated with peak E2 (r = 0.41). There were no differences in the number of preovulatory oocytes retrieved or fertilized or the pregnancy rates between hyperprolactinemic and euprolactinemic patients in each response group or when all hyperprolactinemic and euprolactinemic patients, regardless of E2 response, were compared. Transient hyperprolactinemia during gonadotropin stimulation for IVF occurs and correlates with E2 response but has no impact on IVF outcome.

Adult↗
PubMed1989

Hysterosalpingographic diagnosis of uterine adenomyoma.

True adenomyomas (encapsulated) are uncommon tumors of the uterus. At hysterosalpingography, detection of a network of fine channels in a very well-circumscribed area of the myometrium, connected with the uterine cavity, allows a preoperative diagnosis.

Adult↗