Biomedical subjects

J Smitz

Publications and source records attributed to J Smitz.

At least 55 records · Page 3Linked to original sources

PubMed1999

Oocyte in-vitro maturation and follicle culture: current clinical achievements and future directions.

This paper reviews two recent developments in the field of assisted reproduction: in-vitro culture (IVC) of follicles and in-vitro maturation (IVM) of oocytes. Both in-vitro procedures for oocytes and immature follicles were developed so as to enable storage of ovarian cortical tissue and oocyte-cumulus complexes (OCC) from small follicles. Until now, complete in-vitro development from a primordial follicle up to ovulation has been achieved only in mice. Culture of ovarian cortex from large mammals and humans has revealed that the proliferation and differentiation of pre-granulosa cells is easily switched on, but that within a few days oocyte growth is often compromised. Culture of OCC from preantral follicles from sheep yielded antral follicles after 1 month in a serum-free system and the enclosed oocytes had almost doubled their diameter. Similar work in humans is ongoing, but no consistent successes have been reported as yet. In-vitro maturation of OCC from antral follicles has already been used clinically for more than 10 years. Inspired by the work on bovines, several in-vitro fertilization (IVF) clinics have applied IVM on OCC from different sizes of follicles. The culture conditions needed to provide a reasonable yield of developmentally competent oocytes have not been clearly defined, although some IVF groups have reported live births. To enable the development of consistent techniques of IVC and IVM, a more systematic and scientific approach is needed: use of defined culture media in combination with follicle stage-dependent supplements might improve our understanding of the minimal requirements for oocyte growth and maturation.

Animals↗

PubMed1998

Follicle culture after ovarian cryostorage.

OBJECTIVES: Cryostorage of ovarian cortical tissue, before devastating chemo- and/or radiotherapy for cancer, permits survival of primordial and early preantral follicles. This work aims for a system allowing the long-term maturation in vitro (IVM) of small immature oocytes up to fertilisable metaphase II oocytes. METHODS: A culture system allowing follicle attachment permitted the growth and maturation of isolated follicles (follicle diameter between 100 and 130 microns) from 14-day-old (prepuberal) mice. Follicle and oocyte development were observed under the inverted microscope and conditioned medium was used for biochemical analysis. Effects of recombinant gonadotrophins and oxygen tensions were studied for their specific effects on follicle development. RESULTS: A 12-day culture period yielded full-grown oocytes which were able to complete meiosis (metaphase II). Live young were obtained after IVF and intra-uterine transfer of in vitro matured oocytes. Growth and maturation were only successful when recombinant gonadotropins were added and when the incubator had a 20% oxygen tension. This system enabled the growth of early preantral follicles after cryopreservation: 80% of frozen and thawed follicles survived up to culture-day 12 and yielded a comparable blastocyst formation rate as in controls. CONCLUSIONS: The mouse model suggests that IVM is a valuable option after oocyte storage. The development of a comparable system for long-term culture of human follicles will imply the acquisition of non-invasive techniques to appreciate oocyte's maturity and developmental capacity.

Animals↗

PubMed1998

Effects of recombinant activin A on in vitro culture of mouse preantral follicles.

Activins are part of the intragonadal factors that can modulate the actions of gonadotropins and regulate cellular functions during preantral or early antral stages of folliculogenesis in vivo. In a mouse early preantral follicle culture system, activin A production was measured and recombinant bovine activin A (r-ACT A) was added (10 or 50 ng/ml) to recombinant follicle-stimulating hormone (r-FSH)-supplemented (10 or 100 mIU/ml) medium for a 12-day culture period. Specificity of activin A action was ascertained by addition of recombinant human follistatin (r-FA; 20 or 100 ng/ml). Immunoreactive activin A concentrations in mouse follicle-conditioned medium increased by a factor of 20-50, reaching concentrations from 2 to 5 ng/ml at end of culture. In the initial days of culture, additions of r-ACT A to r-FSH-supplemented medium provoked a dramatic volumetric increase and earlier attachment of the follicle. A dose of 100 ng/ml r-FS was able to block the actions of 10 ng/ml but not those caused by 50 ng/ml r-ACT A. In follicle cultures supplemented with 10 mIU/ml r-FSH, additions of r-ACT induced a dose-dependent inhibin (INH) and estradiol (E2) increase. Basal and human chorionic gonadotropin (HCG)-induced progesterone (P) production were not influenced by r-ACT A or r-FS additions. Addition of r-ACT A decreased (P = 0.017) the intact follicle survival rate and had no influence on final oocyte diameter. In cultures supplemented by 10 mIU/ml r-FSH, additions of r-ACT A did not influence progression and resumption of meiosis I. Use of a higher r-FSH supplementation dose (100 mIU/ml) tended to affect meiosis I adversely (P = 0.052), and r-ACT A addition amplified this effect significantly (P = 0.007). These in vitro experiments demonstrate pronounced effects from r-ACT on r-FSH-mediated follicle survival, growth, and estrogen biosynthesis.

Activins↗

PubMed1998

The luteal phase of nonsupplemented cycles after ovarian superovulation with human menopausal gonadotropin and the gonadotropin-releasing hormone antagonist Cetrorelix.

OBJECTIVE: To analyze the luteal phase of six patients undergoing controlled ovarian hyperstimulation (COH) with hMG and a new GnRH antagonist, Cetrorelix, without receiving luteal phase supplementation. DESIGN: Phase II study involving the first six patients who did not receive luteal phase support. SETTING: Tertiary referral center. PATIENT(S): Six healthy women undergoing COH for assisted reproductive techniques. INTERVENTION(S): Oocyte retrieval was performed 36 hours after hCG administration, followed by embryo transfer 2 days later. No luteal phase supplementation was given. MAIN OUTCOME MEASURE(S): Serum E2, progesterone, LH, and FSH concentrations were measured. RESULT(S): The length of the luteal phase was < or =12 days in three of the six patients. One of the patients in whom the luteal phase was >12 days had a low serum progesterone concentration (2.9 ng/mL) on day 10. Serum LH concentrations decreased after the preovulatory hCG injection in all patients. However, a progressive increase in LH was observed after day 7, reaching normal values. CONCLUSION(S): Corpus luteum function seems to be impaired in cycles that are stimulated with hMG and the GnRH antagonist Cetrorelix.

Adult↗

PubMed1998

Early preantral mouse follicle in vitro maturation: oocyte growth, meiotic maturation and granulosa-cell proliferation.

Mechanically isolated early preantral mouse follicles were cultured singly for 16 d and fully grown oocytes were obtained from these follicles. We then compared in vitro and in vivo follicle growth by trypsinising the follicles and counting their cell numbers in a Neubauer-counting chamber and recording the diameter and meiotic status of oocytes under an inverted microscope. As long as the granulosa cells were within the basal membrane, proliferation was slow. From Day 6, when granulosa cells had broken through the basal membrane, the proliferation rate progressed up to Day 10 and decreased thereafter to approximately 12,000 cells per culture droplet. Incorporation of BrdU revealed that proliferating cells were evenly distributed throughout the follicle until antrum formation. As granulosa cell differentiation progressed, proliferation of mural-granulosa cells ceased, while cells around the oocytes continued dividing. Oocyte diameter increased discontinuously in relation to follicle remodelling. During the first growth phase, diameters increased from 56.5 (+/- 4.4 microns) to 67 (+/- 4.1 microns) until the onset of antral-like cavity formation. The last growth phase started after Day 10, and by Day 14 oocyte diameters were not significantly different from those of 26-d-old in vivo control oocytes. The potential to resume meiosis after mechanical removal of granulosa cells was first reached on Day 8; thereafter, removal of the corona showed that all oocytes cultured with FSH remained arrested at the GV stage up to Day 16. After Day 8, approximately 70% of all oocytes underwent GVBD as a result of granulosa-cell removal, but only 23% of these reached MII after 24 h. The in vivo controls reached a comparable GVBD rate (66%) when the granulosa was removed, but most of the oocytes (82%) underwent first polar body extrusion 24 h later. These results suggest that although oocyte diameters after IVM are not different from those of the controls, culture conditions are not yet adequate to support complete meiotic maturation.

Animals↗

PubMed1998

Epidermal growth factor combined with recombinant human chorionic gonadotrophin improves meiotic progression in mouse follicle-enclosed oocyte culture.

Using a mouse early preantral follicle culture system, mature full grown oocytes, arrested in prophase I of meiosis, were produced after 12 days using a recombinant gonadotrophin-supplemented medium. This culture medium does not mimic the normal extracellular environment of the oocyte and might therefore modify meiotic regulation and more particularly progression to metaphase II (MII). The aim of this study was to optimize the treatment using recombinant stimulatory ligands which were known to induce germinal vesicle breakdown (GVBD) and completion of meiosis I, metaphase II (MII), namely recombinant follicle stimulating hormone (r-FSH), chorionic gonadotrophin (r-HCG) and epidermal growth factor (EGF). Full-grown intrafollicular oocytes could not resume meiosis when the 'ovulatory' stimulus was r-FSH, used at a 100 times higher dose than during culture. r-FSH did not increase progesterone production. When 1.5 IU/ml r-HCG was used as meiotic trigger, germinal vesicle breakdown was obtained in 95% of the oocytes 64% of which extruded a first polar body. r-HCG induced a dramatic increase in progesterone production. When EGF was administered as sole stimulus on day 12 to the attached follicle-enclosed oocytes, only doses > or =5 ng/ml could cause GVBD, although less effectively than r-HCG (45 versus 95%; P < 0.0001). Oocytes undergoing GVBD by the EGF pulse reached metaphase II at a rate of 54% (not significant versus r-HCG). EGF did not stimulate progesterone production. Addition of increasing doses of EGF (0.5; 5; 10; 50 ng/ml) to r-HCG did not increase the GVBD-rate, but EGF doses >5 ng/ml improved MI to MII transition (P=0.027), thereby improving the final yield of MII oocytes by 12.5%. These data show that up to a dose of 50 ng/ml, EGF on its own could only override the somatic inhibitory stimuli in less than half of the cultured follicles. However, in addition to HCG, EGF (25 ng/ml) had a stimulatory effect on completing the first meiotic division. It was concluded that, under the present culture conditions, EGF in combination with HCG provided optimal nuclear maturation.

Animals↗

PubMed1998

Inhibin A and B secretion in mouse preantral follicle culture.

Conditioned media from single mouse ovarian follicles cultured from the early preantral stage up to complete maturity were analysed for different immunoreactive inhibin forms. The inhibin assays measured (i) alpha-specific inhibin, as represented by a mix of 32 and and 57 kDa inhibins, inhibin precursors, alpha-subunit and its precursors; (ii) dimeric inhibin A; and (iii) dimeric inhibin B. The validity of these assays for the measurement of mouse inhibin was established. All forms of inhibin were secreted in culture media from the preantral follicle stage onwards. Inhibin B was the most sensitive marker for proliferation of early stage follicles, while inhibin A secretion became predominant at later stages, when antral-like cavities were formed in granulosa cell masses. Supplementation of standard culture medium with recombinant follicle stimulating hormone appeared to be the predominant regulator of inhibin secretion; addition of recombinant luteinizing hormone throughout the culture period did not cause any major shifts in the expression of dimeric inhibin or alpha-specific inhibin forms. In the absence of theca cells during isolation and culture (as reflected by absence of oestrogen secretion), follicles grew at a reduced rate, and produced lower inhibin concentration in conditioned medium. These data suggest (i) that monitoring of dimeric inhibins can provide useful markers of the growth and differentiation of cultured follicles and (ii) that dimeric inhibins A and B are secreted at an earlier stage in vitro than in vivo.

Animals↗

PubMed1998

Recombinant luteinizing hormone as a survival and differentiation factor increases oocyte maturation in recombinant follicle stimulating hormone-supplemented mouse preantral follicle culture.

The effects of recombinant luteinizing hormone (rLH) and recombinant follicle stimulating hormone (rFSH) both separately and together were analysed on the in-vitro maturation of a well-defined class of mouse early preantral follicles. Metaphase-II (MII) oocytes were only obtained when rLH or rFSH or a combination of both hormones was added to a standard rich culture medium at constant doses throughout the culture period. Without gonadotrophins only 8% of the follicles reached day 12 of culture. Follicle survival was optimal (between 90 and 100%) when rFSH was used; significantly fewer follicles were kept intact when rLH was added as the only supplement (54%; P < 0.001). Theca cells played a fundamental role in follicle survival when rLH was the only supplement. Presence of rLH significantly influenced the formation of antral-like cavities: on day 12, 59% of follicles cultured with rLH + rFSH had a large cavity, as compared with only 21% in cultures with rFSH only (P < 0.0001). The rHCG stimulated germinal vesicle breakdown rate from the different gonadotrophin-supplemented cultures on day 12 was not significantly different (FSH: 89%; LH: 70%; FSH/LH: 83%). However, addition of rLH to rFSH did significantly improve (P < 0.05) the completion of the first meiotic division up to the MII stage (FSH: 46%; LH: 39%; FSH/LH: 76%). Interfollicle differences in steroid production were very large and depended on the presence of theca cells and on the kind of gonadotrophin supplemented. Without theca cells, oestrogen concentrations in rFSH-supplemented cultures were 100 times lower than their theca-containing counterparts during the entire culture period. From culture day 9 onwards most conditioned media had increased basal progesterone concentrations. This study points up the in-vitro role of LH on the differentiation of follicle-like structures and the oocyte's meiotic maturation and suggests an important role for theca cells in providing modulators of in-vitro gonadotrophin action.

Animals↗

PubMed1998

Efficacy and onset of action of fluticasone propionate aqueous nasal spray on nasal symptoms, eosinophil count, and mediator release after nasal allergen challenge in patients with seasonal allergic rhinitis.

We studied the effect and onset of action of fluticasone propionate aqueous nasal spray (FPANS) on mediator release and eosinophil accumulation in nasal secretions and on nasal symptoms of patients with seasonal allergic rhinitis after nasal allergen challenge (NAC). At the end of the pollen season, 28 patients were randomized in a double-blind and crossover design to receive 7 days' treatment with FPANS (200 microg, once daily) and matching placebo. NACs were performed before and at 6 h and 1, 2, 3, and 7 days during treatment with FPANS or placebo. Nasal secretions were collected for a quantitative determination of mediators and eosinophil count before and 5 min after each challenge. Nasal symptoms were assessed by scales grading the severity of symptoms at the same time. Results showed that for mediator concentrations there was a significant decrease of leukotriene C4 (P<0.001) at 7 days after the first administration of FPANS as compared to placebo. Two days after FPANS, both eosinophil counts and eosinophil cationic protein (ECP) concentrations were lower than those of placebo (eosinophils: P=0.032; ECP: P=0.038). The onset became even more important at day 7 (eosinophils: P=0.001; ECP: P=0.009) during the FPANS treatment period. For the subjective nasal symptoms, a significant reduction of symptom scores for nasal obstruction occurred also at day 3 (P=0.017) and for sneezing at day 7 (P=0.003). There was not yet any significant improvement of the objective nasal airway resistance after the different NACs during the study period. In conclusion, this study demonstrated that topical fluticasone propionate is effective in the treatment of mucosal inflammation induced by NAC. For optimal control of nasal symptoms induced by repeated maximal allergen challenges, a treatment period of more than 1 week is required.

Administration, Intranasal↗

PubMed1998

Lumbar spine bone mineral density in diabetic children with recent onset.

To detect early abnormalities in bone mineralization, the lumbar spine bone mineral density (BMD) of diabetic children with a diabetes onset of less than 5 years and treated with a similar insulin treatment scheme was measured at the level of the lumbar spine by dual-energy X-ray absorptiometry (DEXA), a most sensitive technique for detecting osteopenia in children. Fifteen male and 8 female children and adolescents (mean age +/- SD: 12.5+/-3.7 years), 1-5 years after the clinical onset of their diabetes, were studied. Measurements of the lumbar spine (L1-L4) BMD, expressed in gHA/cm2 and as a z-score for age, were performed with a commercial DEXA apparatus (Hologic QDR 1000 W, Hologic Inc., Waltham, USA). Calcium-phosphorus metabolism was studied by measuring the circulating levels of calcium, phosphorus, alkaline phosphatase, osteocalcin, 25-OH-vitamin D and parathyroid hormone and the urinary excretion of calcium and phosphorus. The mean BMD of the studied group was 0.75 (0.16) gHA/cm2 giving a mean z-score of -0.31+/-0.95. Only 1 of the patients had a BMD lower than -2 SD. No sex difference in BMD z-score existed. BMD SD was positively correlated with height SD (R = 0.56, p < 0.005), but not with the age of the patients, the duration of the disease, the degree of metabolic control or the studied parameters of the calcium-phosphorus metabolism. In conclusion, diabetic children have a normal lumbar spine BMD during the first years of the disease, when a good metabolic control and no abnormalities in the calcium-phosphorus metabolism are present. As in normal children, areal BMD by DEXA is highly dependent on the body height, necessitating corrections if abnormalities in skeletal growth or pubertal development exist.

Absorptiometry, Photon↗

PubMed1998

Study of serum leptin in cafeteria-diet-overfed rats. Influence of diet, insulin and corticosterone.

In a group of 15 male Wistar rats overfed with cafeteria foods (delivering a mean fat percentage of 60%) during 5 months from the age of 8 weeks and in a control group of 15 rats fed with a standard chow for the same period, serum leptin, insulin and corticosterone were measured by RIA and body composition was determined by dual-energy X-ray absorptiometry. Significantly higher fasting serum concentrations of leptin, insulin and corticosterone were found in the cafeteria-diet group. Fasting leptin concentrations were significantly higher in rats with a body fat percentage of more than 25% compared to the others, irrespective of the type of feeding. The log serum leptin correlated positively with body fat percentage and fasting insulin concentration but not with corticosterone concentration. Leptin concentration corrected for body fat mass was, however, comparable between the two diet groups, while the leptin/insulin ratio was lower in the cafeteria-diet group. In conclusion, chronic overfeeding resulting in an increased body fat percentage in rats is associated with hyperleptinemia, hyperinsulinemia and hypercorticism. Serum leptin levels appear to primarily track total body fat percentage and are unaffected by dietary fat manipulation in cafeteria-diet-induced obese rats.

Absorptiometry, Photon↗

PubMed1998

Pituitary growth hormone release and gene expression in cafeteria-diet-induced obese rats.

In human obesity as well as in rat obesity models a decrease in spontaneous and stimulated GH secretion has been a constant finding. The presence of a decreased pituitary GH synthesis in diet-induced obese male rats was investigated and its possible relationship with obesity-related changes in peripheral hormones was analyzed. Cafeteria-diet-overfed obese male Wistar rats with body fat percentage above 30% had a significantly decreased pituitary GH mRNA transcript level assessed by both Northern blot and in situ hybridization, and a lower pituitary GH protein level as demonstrated by immunocytochemistry. The GH transcript level correlated negatively with the serum leptin and positively with the IGF-I concentration. No differences in circulating tri-iodothyronine, non-fasting insulin and corticosterone levels were found between overfed and control rats. GH release by cultured pituitary cells from overfed rats was comparable to that by cells prepared from control rats. In contrast, incubation of normal pituitary cells with serum from overfed rats for 3 days gave a significantly lower GH release than after incubation with serum from non-obese rats. In conclusion, cafeteria-diet-induced obese male Wistar rats have a decreased pituitary GH gene expression and a modifiable GH release in in vitro experiments. A possible role for peripheral circulating factors, like leptin and IGF-I, in decreasing the pituitary GH synthesis and release in obese rats is discussed.

Animals↗

PubMed1997

Endometrial evaluation by aspiration biopsy on the day of oocyte retrieval in the embryo transfer cycles in patients with serum progesterone rise during the follicular phase.

OBJECTIVE: To investigate the effect of subtle serum P rise before hCG administration on endometrial maturation in stimulated cycles. DESIGN: Case-control study. SETTING: Tertiary referral center. PATIENT(S): Twenty patients with serum P < or = 0.9 ng/mL (group I) (conversion to SI unit, 3.180), 20 patients with premature P rise (> or = 1.1 ng/mL, group II), and 20 patients with normal serum P (group III). INTERVENTION(S): Patients in groups I and II underwent endometrial aspiration biopsies on the day of oocyte retrieval in the ET cycles themselves. Patients in group III, without endometrial biopsies, were chosen as controls. MAIN OUTCOME MEASURE(S): Comparison of endometrial maturation, correlation between endometrial dating and cumulative P exposure, and/or number of days of P > or = 1.1 ng/mL and comparison of clinical outcome. RESULT(S): Groups I and II showed a secretory activity of the endometrium. In group II, the endometrial dating correlated neither with P exposure nor with the number of days of subtle P rise. Clinical pregnancies were observed in both groups but none in cases with endometrium advanced > 3 days. Similar pregnancy and implantation rates were observed between groups I and III. CONCLUSION(S): These data suggest that an endometrial aspiration biopsy performed on the day of oocyte retrieval may be used to assess endometrial receptivity in patients with serum P rise.

Abortion, Spontaneous↗

PubMed1997

Comparison of different doses of gonadotropin-releasing hormone antagonist Cetrorelix during controlled ovarian hyperstimulation.

OBJECTIVE: To assess the minimal effective dose of a GnRH antagonist (Cetrorelix; Asta Medical; Frankfurt, Germany) to prevent premature LH surge in patients undergoing controlled ovarian hyperstimulation (COH) for assisted reproductive technologies. DESIGN: In 69 patients COH was carried out with the association of hMG, starting on day 2 of the menstrual cycle, and a GnRH antagonist (Cetrorelix) was administered from day 6 of the hMG treatment (day 7 of the menstrual cycle) every day up to and including the last day of the hMG injection. In 32 and 30 patients, 0.5 mg and 0.25 mg of Cetrorelix were administered, respectively. Seven patients received 0.1 mg of Cetrorelix. SETTING: Tertiary referral center. RESULT(S): No premature endogenous LH surge occurred in patients treated with 0.5 and 0.25 mg of Cetrorelix, and serum LH concentrations were maintained constantly low during the entire follicular phase in both groups. Follicle-stimulating hormone, LH, E2, and P expressed as area under the curve were similar in both groups. A premature LH surge (18 mIU/mL; conversion factor to SI unit, 1.00) with a concomitant P rise (1.7 micrograms/L; conversion factor to SI unit, 3.180) occurred in one of the seven patients treated with 0.1 mg Cetrorelix; therefore, treatment with this dose was discontinued. CONCLUSION(S): The minimal effective dose of Cetrorelix able to prevent premature LH surge in COH cycles is 0.25 mg administered daily.

Adult↗

PubMed1997

Relationship between serum follicle stimulating hormone in the male and standard sperm parameters, and the results of intracytoplasmic sperm injection.

Serum follicle stimulating hormone (FSH) is routinely measured when evaluating the infertile male for intracytoplasmic sperm injection (ICSI). However, among the sperm parameters, only its relationship with sperm concentration is well documented. Few investigations concern the relationship between FSH and sperm motility and morphology, and the results of ICSI. A retrospective study of 316 couples who underwent ICSI was carried out to determine the relationships between serum FSH concentrations in the male and (i) standard sperm parameters_(concentration, motility and morphology) and (ii) fertilization, cleavage, pregnancy and implantation rates after ICSI. There was an inverse correlation with sperm concentration and total motility but no relationship was found with progressive motility and sperm morphology. Neither was any relationship found between serum FSH and fertilization, cleavage, pregnancy and implantation rates, and the results of ICSI. These findings suggest the need to review the routine measurement of serum FSH in the infertile male when ICSI is the planned treatment procedure.

Female↗

PubMed1997

Ovulation by repeated human chorionic gonadotrophin in 'empty follicle syndrome' yields a twin clinical pregnancy.

This case illustrates the possibility of obtaining oocytes that fertilize and cleave normally after the administration of a second ovulatory dose of human chorionic gonadotrophin (HCG) in a case of 'empty follicle syndrome'. The present patient underwent ovarian stimulation with gonadotrophin-releasing hormone analogue (GnRHa)/menotropin for intracytoplasmic sperm injection (ICSI). After the failure of the first oocyte retrieval, a second dose of HCG was administered to trigger ovulation. A total of 13 oocytes was retrieved during the second procedure and 11 good quality embryos were obtained (fertilization and cleavage rates of 92 and 91% respectively). No pregnancy was achieved after the replacement of three embryos. In a subsequent cycle stimulated with clomiphene citrate, three frozen-thawed embryos were replaced and a twin pregnancy was achieved. The patient delivered two healthy babies at term.

Adult↗

PubMed1997

Assessment of the need for follicle stimulating hormone in early preantral mouse follicle culture in vitro.

In two consecutive controlled experiments 160 early preantral follicles were cultured in order to evaluate effects of recombinant follicle stimulating hormone (r-FSH) on survival, differentiation, oestradiol and inhibin secretion, cumulus mucification and cumulus-corona-oocyte detachment by human chorionic gonadotrophin (HCG) stimulation. Nuclear maturation in oocytes was also assessed following addition of HCG. A histological analysis of cultured follicles was carried out on semi-thin sections at various culture stages. Addition of r-FSH was essential for follicle survival for 16 days: without r-FSH only 11% of the follicles survived for 12 days (with r-FSH: 79%) and none of these mucified after the HCG stimulus. r-FSH promoted granulosa cell proliferation and antral-like cavity formation. Without r-FSH, histology of the cultures demonstrated degeneration and reduced granulosa cell proliferation; oestradiol and inhibin production were reduced. This study illustrates the essential role of FSH in promoting the in-vitro growth of early preantral mouse ovarian follicles and in maintaining the oocyte under meiotic arrest.

Animals↗

PubMed1997

An approach to the understanding of the nasal early-phase reaction induced by nasal allergen challenge.

Quantitative determinations of the inflammatory mediators in nasal secretions were performed and correlated with the objective nasal symptoms within 1 h after nasal allergen challenge (NAC). Twenty-six patients with seasonal allergic rhinitis were enrolled outside the pollen season. All measurements were performed before (as a baseline control) and at 1, 5, 10, 30, and 60 min after NAC. This study aimed to clarify the pathogenic mechanism of the early-phase reaction (EPR) by monitoring the evolution of early-phase mediators in nasal secretions and the presence of nasal symptoms during this period. The results showed that, after NAC, the maximal mediator concentration was already reached after 1 min for histamine (124 ng/g), 5 min for tryptase (56 microU/g), and 5-10 min for leukotriene C4 (40 ng/g). Itching and sneezing started as early as 20-30 s, and they were predominant symptoms within 5 min. Rhinorrhea and nasal obstruction started a few minutes after NAC and lasted until more than 1 h after NAC. There was no significant correlation between any single mediator and nasal symptoms during the sampling period. In conclusion, this study demonstrated that during the EPR the presence of nasal symptoms involves a complex mechanism, reflecting the interaction between the mediators released by inflammatory cells, and the receptors on different target organs. When evaluating symptoms during the EPR, one must consider not only the severity of these symptoms but also the time period within which these symptoms occur. For the symptoms of nasal obstruction and rhinorrhea, the early-phase reaction often lasted more than 1 h.

Adult↗