Biomedical subjects

A G Byskov

Publications and source records attributed to A G Byskov.

At least 55 records · Page 3Linked to original sources

PubMed1997

Reduced in vitro fertilization of human oocytes correlates with raised circulating FSH levels during ovarian stimulation in normogonadotropic women downregulated with GnRH-analogues.

PURPOSE: The possible effects of circulating FSH levels as used during IVF treatment on oocyte maturation and subsequent preembryo development were evaluated. METHODS: Serum levels of FSH and LH on days 1 and 8 of ovarian stimulation and on the day of oocyte retrieval (OR) were correlated with subsequent preembryo development in vitro. After pituitary downregulation, 244 normogonadotropic women followed a fixed protocol for the first 7 days of stimulation. RESULTS: The average FSH concentration on day 8 of stimulation was 11.5 IU/L and exceeded the expected midcycle surge of FSH by more than 25%. In contrast, levels of LH were below an average of 2 IU/L throughout the stimulation period. The concentration of FSH on day 8 and on the day of OR showed a significant inverse correlation with cleavage rate, whereas levels of LH, age, and body mass index showed no such correlation. CONCLUSIONS: Supraphysiologic levels of FSH seems to affect oocyte maturation negatively. Premature resumption of meiosis, leading to retrieval of postmature oocytes with a reduced developmental potential, is suggested as the underlying mechanism.

Adult↗

PubMed1997

Does corpus luteum locally affect follicular growth negatively?

In this study bilateral ovarian follicular growth during the luteal phase was investigated in relation to the ovary where ovulation occurred. The diameter of the largest follicle in the contralateral ovary without corpus luteum and in the ipsilateral ovary with corpus luteum was measured using vaginosonography in a total of 66 natural cycles of 27 normally cycling women undergoing treatment with intrauterine insemination (IUI). None of the women received ovarian stimulation or luteal support. Follicles from 2 to 11 mm in diameter were measured in early luteal phase (day +1 to +4), mid-luteal phase (day +5 to +9) and late luteal phase (day +10 onwards). The mean diameters of the largest follicle in the contralateral ovary without corpus luteum during the early, mid- and late luteal phases were 6.81 +/- 1.33 (mean +/- SD), 6.14 +/- 1.29 and 5.71 +/- 1.17 mm respectively, while those of the ipsilateral ovary with corpus luteum were 6.48 +/- 1.40, 5.65 +/- 1.47 and 4.98 +/- 1.19 mm respectively. While there was no significant difference during the early luteal phase, the mean diameter of the largest follicle in the ipsilateral ovary with corpus luteum was significantly smaller than that of the contralateral ovary without corpus luteum during the mid-luteal phase (P < 0.004) and the late luteal phase (P < 0.0005). These results indicate that the corpus luteum locally affects neighbouring follicular growth negatively during the luteal phase of the menstrual cycle, with the most pronounced effect expressed in the mid- and late luteal phases.

Adult↗

PubMed1997

The cortex-medulla oocyte growth pattern is organized during fetal life: an in-vitro study of the mouse ovary.

The cortex-medulla growth pattern of oocytes in the developing ovary is formed by a rim of small non-growing oocytes at the periphery and growing oocytes at the inner part of the cortex and in the medulla. In this study we aimed to: (i) develop an in-vitro model using fetal mouse ovaries to evaluate when the cortex-medulla growth pattern is organized during ovarian differentiation; and (ii) study the interaction between small, non-growing and growing oocytes. Fetal mouse ovaries of days 11, 13 and 16 post coitus (E11, E13 and E16) were cultured for 14, 12 and 9 days respectively, corresponding to post-partum day 7 (P7). A cortex-medulla growth pattern had developed by P7 in most ovaries from E16 and in half of those from E13. No ovaries from E11 developed a cortex-medulla pattern. The organization of this pattern within the ovary is concurrent with the initiation of meiosis. Ovaries with a cortex-medulla growth pattern had the same number of growing follicles (approximately 87), regardless of the number of small, non-growing oocytes present. In contrast, in most ovaries without a cortex-medulla pattern, almost all oocytes began to grow. Hence, the geographically determined growth pattern of oocytes in the developing mouse ovary may be organized at the onset of meiosis and is sustained by a balanced interaction between small and growing follicles.

Animals↗

PubMed1997

Enhanced separation of X and Y bearing sperm cells by a combined density gradient centrifugation evaluated by fluorescence in situ hybridization of the Y-chromosome.

OBJECTIVES: Fluorescent in situ hybridization of decondensed sperm cells was used to evaluate the effectiveness of separating X- and Y chromosome bearing sperm cells using a combination of Percoll and NycoPrep media. MATERIAL AND METHODS: Semen samples from seven healthy men were divided into three equal aliquots. One aliquot served as an untreated control, the other two were either applied to a seven-step Percoll gradient (100%-40%), or to a seven-step Percoll gradient (100%-40%) underlayered with 100% NycoPrep for sperm purification. After centrifugation Y-bearing sperm cells in the pellet and in the control sample was determined by fluorescent in situ hybridization. RESULTS: A significantly reduction of Y-bearing sperm cells were observed in the pellet of the Percoll + NycoPrep centrifugation (39.3% Y-bearing sperm cells) compared to the control sample and to Percoll centrifugation without NycoPrep. The Percoll centrifugation without NycoPrep did not show a significant reduction of Y-bearing sperm cells in the pellet compared to the control sample. CONCLUSION: By the addition of a medium with a density higher than 100% Percoll a significantly increased separation of X and Y-bearing sperm cells can be achieved. This study opens new perspectives for improving separation of X- and Y-bearing spermatozoa by simple centrifugations. The described centrifugation technique can be applied in connection with preimplantation diagnosis in order to create more pre-embryos of the desired gender.

Cell Separation↗

PubMed1996

Contralateral selection of dominant follicle favours pre-embryo development.

Ovulation was studied using vaginosonography in a total of 410 natural cycles of 123 women undergoing infertility treatment [267 intrauterine insemination (IUI) cycles of 103 women and 143 in-vitro fertilization (IVF) cycles of 50 women]. None of the women received ovarian stimulation. Each follicle was measured daily from 14 mm in diameter until formation of corpus luteum or oocyte retrieval. Contralateral ovulation as compared with the preceding cycle occurred in 57% of the 410 cycles. Contralateral ovulations occurred in 72% of cycles with a follicular phase < 13 days. In cycles with a follicular phase of > 14 days, ovulations occurred at random. The length of follicular phase in contralateral ovulation cycles (15.2 +/- 3.2 days) was significantly (P < 0.05) shorter than that of ipsilateral ovulation cycles (15.8 +/- 2.8). During the 57% contralateral ovulations in 143 IVF cycles, the rates of oocyte retrieval (89%), fertilization (69%), cleavage (90%) and embryo transfer (56%) were significantly higher than those of ipsilateral ovulations (69, 51, 64 and 23% respectively). The pregnancy rate of contralateral ovulations (9%) was also higher, though not significantly, than that of ipsilateral ovulations (3%), although the pregnancy rates per transfer were similar (16 and 14% respectively). The total pregnancy rate of both IUI and IVF was higher in contralateral than in ipsilateral ovulation cycles (8.1 and 4.0% respectively). The dominant follicles in contralateral ovulation cycles showed significantly higher oestradiol/androstenedione ratio (P < 0.025) and oestradiol/testosterone + androstenedione ratio (P < 0.025) and lower androstenedione (P < 0.05) than those of ipsilateral ovulation cycles. There was no significant difference in oestradiol, progesterone and testosterone. These results indicate that the dominant follicles in contralateral ovulation cycles are healthier than those of ipsilateral ones. Local intra-ovarian factors, e.g. from the corpus luteum, may negatively affect the health of the dominant follicle and the enclosed oocyte. Therefore contralateral selection of the dominant follicle in the succeeding cycle may favour pre-embryo development. The chance of conceiving during a natural cycle may be affected by the site of ovulation in the preceding cycle.

Embryonic and Fetal Development↗

PubMed1995

Chemical structure of sterols that activate oocyte meiosis.

Gonadotrophins and various growth factors, but not sex steroids, can induce resumption of meiosis in vitro, but only in oocytes enclosed by cumulus-granulosa cells. Follicular purines prevent resumption of meiosis. This process can be overcome, in vitro, by a transient elevation of cyclic AMP resulting in the production of a diffusible meiosis-inducing substance secreted by the cumulus cells. A meiosis-inducing activity has been detected in gonads of different species, for example, in preovulatory follicular fluid of women and in mouse testes. We report here the isolation and characterization of meiosis-activating sterols from human follicular fluid and bull testes and the synthesis of two closely related C29 sterols. All these sterols induce a resumption of meiosis in cultured cumulus-enclosed and naked mouse oocytes indicating their nonspecificity across species and sex. This family of sterols is for the first time considered crucial to meiosis.

Animals↗

PubMed1995

Healthy and atretic follicles: vaginosonographic detection and follicular fluid hormone profiles.

The health status of human preovulatory follicles was prospectively studied by non-invasive transvaginal ultrasound. Daily ultrasound scans were performed from the time when the follicle measured 15 mm in diameter until formation of corpus luteum or oocyte retrieval. Based on the ultrasound scans two types of follicles were defined: type A follicles showed a cloud visualized as a cone projecting into the follicular fluid with the base of the cone positioned on the follicle wall. A light spot seen at the tip of the cloud in the majority of scans was presumed to be the oocyte-cumulus complex. Type B follicles showed an echo free space without a cloud. Two groups of infertility patients were studied: Group I received intrauterine insemination; 106 patients undergoing a total of 263 cycles (188 spontaneous cycles and 75 clomiphene citrate cycles). Group II received in-vitro fertilization (IVF); 22 patients undergoing a total of 52 cycles (31 spontaneous cycles and 21 clomiphene cycles). In the first group, the ovulatory potential of the follicle is associated with the ultrasound characteristics. From the IVF patients the follicular fluid was harvested and assessed for the free concentration of the following steroids: oestradiol, progesterone, testosterone and androstenedione. The endocrine health status of the follicle was associated with the ultrasound characteristics of the follicle. In patients of group I, 288 type A follicles ovulated out of a total of 298 follicles (97%). None of the type B follicles ovulated (0/14). In patients of group II, oocytes were obtained in 79% of the type A follicles (50/63), whereas 7% of the type B follicles yielded an oocyte (1/14).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Cumulus cells secrete a meiosis-inducing substance by stimulation with forskolin and dibutyric cyclic adenosine monophosphate.

The role of the cumulus cells in initiating the resumption of meiosis after exposure to forskolin and dbcAMP was studied in the mouse. The resumption of meiosis was monitored by the percentage of germinal vesicle breakdown (GVBD) and polar body formation (PB). The cumulus-enclosed oocytes (CEO) and denuded oocytes (DO) were cultured with and without hypoxanthine (HX) in the culture medium. Three types of experiments were performed: (1) Effect of forskolin on spontaneous resumption of meiosis, i.e. cultures without HX, and two experiments in which HX is present throughout the culture: (2) Effect of transient exposure to forskolin or dibutyric-cyclic adenosinemonophosphate (dbcAMP) on GVBD prior to continued culture without forskolin or dbcAMP (oocyte priming). (3) Priming of CEO with forskolin for 2 hr, separation of cumulus cells and oocytes, followed by coculture of rejoined cumulus cells and oocytes, or coculture of the cumulus cells and new, unprimed DO. (1) Forskolin inhibited a spontaneous resumption of meiosis in a dose-dependent manner during the first 5 hr of culturing. After 22 hr all controls and CEO resumed meiosis, whereas only half of the DO did. (2) At least 1 hr of priming the CEO with forskolin is needed to induce GVBD and PB formation, but forskolin inhibited the resumption of meiosis when present for 24 hr. Similar results were obtained with a high concentration of dbcAMP. (3) A separation and rejoining of oocytes and cumulus cells after priming induced the resumption of meiosis in a significantly greater number of oocytes than in the control oocytes which were not primed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Forskolin and the meiosis inducing substance synergistically initiate meiosis in fetal male germ cells.

We have shown that Meiosis Inducing Substance (MIS) and forskolin synergistically and dose dependently induce meiosis in germ cells of cultured fetal mouse testes. We used a bioassay which consists of fetal mouse testes and ovaries cultured for 6 days. In this study MIS media are spent culture media from 24 hour cultures of minced adult mouse testes. In the bioassay one gonad of each fetus is cultured either in MIS medium, in control medium with forskolin, or in MIS medium with forskolin. The other gonad serves as the control and is cultured in control medium. After culture the gonads are fixed, squashed, and DNA-stained. In these preparations germ cells and somatic cells can be distinguished, and the number of germ cells in the different stages of meiosis is counted as is the number of somatic cells in mitosis. MIS activity is defined to be present in a medium when meiosis is induced in male germ cells during culture. We found that MIS media as well as forskolin induced meiosis in fetal male germ cells in a dose-dependent manner. In addition, MIS media and forskolin acted synergistically by inducing meiosis. Female germ cells seem to be unaffected by the various culture media. These findings indicate that receptors for stimuli of meiotic initiation may exist in germ cells or neighbouring somatic cells. In addition to induction of meiosis, MIS media and forskolin also dose dependently increase the number of male germ cells compared to controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Impact of gonadotrophin dose on pre-embryo recovery and development in superovulated mice.

A dose-response analysis was performed by stimulating mice with Humegon, which contains approximately equal amounts of follicle stimulating hormone (FSH) and luteinizing hormone (LH). The effect of increasing stimulation was assessed by monitoring the number and developmental stages of pre-embryos flushed from the tubes, and the developmental potency of these pre-embryos after culturing for 72 h. Increasing the stimulation doses resulted in an increased recovery of 2-cell pre-embryos. A maximal plateau of 40-50 2-cell pre-embryos was reached after stimulation with 15-30 IU FSH/LH. Higher stimulation doses up to 50 IU FSH/LH showed no further increase in pre-embryo recovery. Increased stimulation doses did not affect the number of 1-cell pre-embryos or the number of pre-embryos which developed further than the 2-cell stage. An average of 88 +/- 1.7% of the flushed pre-embryos were 2-cell pre-embryos. The fraction of flushed pre-embryos which developed into blastocysts after 72 h of culturing was constant at all stimulation doses, with an average of 81 +/- 1.9%. A maximal plateau of 35-40 blastocysts was reached after stimulating with 15-30 IU FSH/LH. The group of pre-embryos at less advanced developmental stages and the group of degenerated pre-embryos showed a small but dose dependent increase in number. In conclusion, we found that increasing doses of Humegon resulted in an increased recovery of pre-embryos capable of preimplantation development. This increased recovery occurred despite the high level of LH contained in this FSH/LH stimulation.

Animals↗

PubMed1993

Lithium stimulates the first meiotic division in mouse oocytes.

Cumulus enclosed oocytes, cumulus enclosed oocytes denuded of their cumulus and cumulus free oocytes from 21 day old unstimulated mice were cultured for 18 hours in control medium supplemented with lithium chloride, dbcAMP and forskolin at various concentrations. In control medium 66% of the cumulus enclosed oocytes, 93% of the denuded oocytes, and 94% of the cumulus free oocytes resumed meiosis (germinal vesicle breakdown), whereas the levels of polar body formation were 27%, 12% and 39%, respectively. In the presence of lithium significantly more cumulus enclosed oocytes and cumulus free oocytes resumed meiosis and formed a polar body, whereas lithium had no effect on the denuded oocytes. Forskolin and dbcAMP stimulated resumption of meiosis and cumulus expansion in the cumulus enclosed oocytes and inhibited resumption of meiosis in the cumulus free oocytes. Lithium more or less eliminated this inhibitory effect of both forskolin and dbcAMP in the cumulus free oocytes. The results indicate (i) that activation of the cAMP second messenger path in the cumulus cells induces them to synthesize a meiosis inducing substance(s) which stimulates the oocyte to resume meiosis, and (ii) that other second messenger systems than the cAMP pathway, e.g. the phosphatidylinositol cycle, are involved in resumption of meiosis and polar body formation. We conclude that lithium enhances the capability of mouse oocytes for resumption of meiosis and polar body formation.

Animals↗

PubMed1992

Changes induced in serum protein profiles by ovarian stimulation during in-vitro fertilization--embryo transfer treatment: a comparison between conception and non-conception cycles.

The profiles of plasma protein concentrations during the follicular phase in unstimulated women and in women undergoing ovarian stimulation for in-vitro fertilization--embryo transfer (IVF-ET) treatment are described. Plasma protein concentrations are correlated with those of total oestradiol (protein-bound and free) and total progesterone. In addition, 10 conception cycles and 18 non-conception cycles are compared in an attempt to identify predictors of successful treatment. Ovarian stimulation caused a significant increase in follicular phase in serum concentrations of sex hormone binding globulin (SHBG), cortisol binding protein (CBP) and insulin-like growth factor binding protein 1 (IGFBP1). In contrast no increase was observed in unstimulated cycles. Serum levels of endometrial protein PP14 decreased significantly during the follicular phase in both stimulated and unstimulated cycles. Levels of pregnancy zone protein (PZP) were more than doubled at the time of oocyte aspiration compared to the unstimulated cycles. Albumin concentrations were unchanged by the stimulation. Throughout the follicular phase, levels of SHBG were significantly higher, and total oestradiol significantly lower in women who became pregnant, than in those who did not. Therefore, a low concentration of free, biologically active oestradiol seemed to favour pregnancy, as the concentration of albumin is similar in the two groups. The endometrial protein PP14 was significantly lower during the follicular phase in conception than in non-conceptional cycles. On day 2 of the treatment cycle, the PP14 concentration showed a 75% correct prediction of conception and non-conception cycles. These results suggest that levels of PP14 may predict successful IVF cycles even before hormonal treatment is commenced.

Adult↗

PubMed1992

Human preovulatory follicular fluid: inhibin and free steroids related to optimal follicular maturation in ovarian stimulation regimes and possible function in ovulation.

Concentrations of inhibin, total and free oestradiol and progesterone were determined in preovulatory follicular fluid from 15 women undergoing in-vitro fertilization and embryo transfer treatment. The women underwent ovarian stimulation using clomiphene citrate and human menopausal gonadotrophin (HMG) (69 follicular fluid samples) in one cycle, and gonadotrophin-releasing hormone agonist (GnRHa) and HMG stimulation in the next treatment cycle (64 follicular fluid samples). The women thereby served as their own control. Inhibin, total oestradiol and progesterone were measured by radioimmunoassay. Concentrations of free steroid were calculated after quantitation of the steroid binding proteins, i.e. sex-hormone binding globulin (SHBG), cortisol binding protein (CBP) and albumin. Levels of inhibin and free and total progesterone were significantly higher in follicular fluids collected after stimulation with the GnRHa compared to the clomiphene regime (P less than 0.05, P less than 0.001, P less than 0.001, respectively). In contrast, levels of total and free oestradiol in follicular fluid were significantly lower after stimulation with GnRHa than after clomiphene stimulation (P less than 0.001). These results indicate that the follicles have achieved a more optimal maturation during the GnRHa regimen than during the clomiphene regime. It is suggested that the concentration of free biologically active steroids in follicular fluid, released into the peritoneal cavity during ovulation, may be physiologically important in stimulating the oviduct and the uterus in connection with ovulation, pre-embryo development and implantation.

Albumins↗

PubMed1991

[Human serum albumin as the protein source in culture of human oocytes, spermatozoa and pre-embryos].

In the treatment of infertility employing in vitro fertilisation and embryo transfer (IVF-EF), oocytes, spermatozoa and pre-embryos are cultured for 48 hours outside the woman's body before they are introduced into the uterus. In addition to the necessary salts, the media in which this culture takes place, also consists of a source of protein. In order to eliminate the variability of patient sera, a prospective, randomized investigation was performed to elucidate whether a well-defined source of protein such as human serum albumin (hSA-hSA 200 mg/ml, Statens Seruminstitute) can replace patient serum as source of protein in the culture of oocytes, spermatozoa and pre-embryos in IVF-ET treatment. The pregnancy rate per transplantation was increased from 30% in the serum group (21 pregnant out of 69 transplantations) to 39% in the albumin group (26 pregnant out of 66 transplantations) but the difference is not significant. On the other hand, the quality of the pre-embryos as assessed by morphological criteria became significantly better and the implantation rate per transplanted pre-embryo was found to be significantly increased in the albumin group. On the basis of this investigation, hSA is recommended as the source of protein, rather than the patient's own serum in the culture of oocytes, spermatozoa and pre-embryos in IVF-ET treatment.

Blastocyst↗

PubMed1991

NCAM in developing mouse gonads and ducts.

The expression of the Neural Cell Adhesion Molecule, NCAM, in mouse gonads and ducts was studied from fetal life to maturity. The methods used were immunocytochemical staining and Western blotting. The immunocytochemical studies showed that the only structures that remain NCAM-positive throughout life were the mesonephric-derived rete ovarii and rete testis. Also in the fetal gonads some somatic cell lining the groups of differentiating germ cells were stained. In the immature as well as in the mature ovary the granulosa cells and oocytes of growing and large follicles--but not of small follicles--were stained. A particularly strong staining of the cytoplasm of the oocyte, healthy as well as atretic, was seen. All cells of the testis remained negative except for weakly stained residual bodies and late spermatids. At all ages the male ducts showed only weak staining, whereas in the female Müllerian duct the epithelium became strongly positive at puberty. The stroma of the Müllerian duct was positive during a transitory period around day 16 of fetal life in both sexes. One-dimensional gel immunoblotting of total protein from gonads, rete and ducts from immature and mature mice showed that only the two largest isoforms of NCAM (NCAM-A and NCAM-B) were present. The gonads and the rete of both sexes and the adult uterus expressed only NCAM-B, whereas NCAM-A was also detected in the adult epididymis. The present findings suggest that NCAM may be involved in the normal development and formation of both the gonads and ducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Epidermal growth factor in small antral ovarian follicles of pregnant women.

Levels of epidermal growth factor (EGF) and steroids were measured by radioimmunoassay in follicular fluid (FF) aspirated from 114 small antral follicles with diameters from 1 to 6 mm and in serum from 19 women undergoing Caesarean section at term. Concentrations of EGF in FF were inversely and significantly correlated to follicular size, being 4.7 +/- 0.4 (mean +/- S.E.M.) nmol/l in follicles of 1-2 mm in diameter and declining to 2.2 +/- 0.2 and 1.4 +/- 0.2 nmol/l in follicles of 3-4 mm and 5-6 mm in diameter respectively. The mean +/- S.E.M. concentration of EGF in serum (0.7 +/- 0.03 nmol/l) was significantly lower than that in FF. Levels of EGF, progesterone and oestradiol in FF were not significantly correlated to one another. In contrast to EGF, levels of progesterone and oestradiol in FF did not vary significantly with follicular diameter in these small follicles. On the basis of these results we suggest that EGF is synthesized in small human antral follicles, and that EGF stimulates granulosa cell proliferation and follicle growth up to 6 mm in diameter. Furthermore, the high intrafollicular levels of EGF may protect the small follicles against untimely effects of high levels of FSH, for instance during the mid-cycle surge of gonadotrophins. It is concluded that EGF plays an important role as an autocrine and/or paracrine regulator of development of small antral follicles in women.

Adolescent↗

PubMed1989

[In vitro fertilization and embryo transfer. 1. The first 100 pregnancies].

The results of treatment of infertility by in vitro fertilization and embryo transfer (IVF-ET) in Rigshospitalet, Copenhagen, are reviewed for 143 patients in whom treatment was completed during the period 1.9.1985-21.2.1988 and for 100 pregnancies during the period 1.9.1985-15.11.1988. Among the 143 patients in whom treatment was completed, 48 became pregnant on one or more occasions as pregnancy occurred in 53 cycles. A total of 44 women delivered 55 infants. There were 35 singleton deliveries, seven twin deliveries and two triplet deliveries. One woman became biochemically pregnant, four aborted before the 12th week of pregnancy an one woman aborted on two occasions in the second trimester. Three women were treated operatively for extrauterine pregnancies. A total of 33.6% of the patients became pregnant, the baby-take-home rate per patient was 30.8%, the pregnancy rate per ET was 23.5% and the delivery rate per transplantation was 19.6%. Non-completed pregnancies per pregnant woman were 20.8%. Only preliminary account of the 100 pregnancies can be given as treatment has not been completed in all of these patients. Among the 100 pregnancies, there were 59 singleton pregnancies, ten twin pregnancies and three triplet pregnancies and 29 pregnancies which were not completed. The age distribution of the pregnant and non-pregnant women (23% over 34 years became pregnant and 53% under 29 years became pregnant) emphasizes the importance of commencing treatment as early as possible.

Denmark↗

PubMed1987

Fertility in two cats with X-chromosome mosaicism and unilateral ovarian dysgenesis.

Two pregnant cats showed unilateral ovarian dysgenesis at surgery. Cytogenetic examination revealed a 37,X/39,XXX karyotype in Cat 1, a 37,X/38,XX karyotype in Cat 2 and a marked difference in frequency of mosaicism between fibroblasts and lymphocytes in both cats. Histologically the ovarian morphology ranged from normal to complete dysgenesis in both cats. Three fetuses examined showed a normal feline karyotype.

Animals↗