Biomedical subjects

L Krey

Publications and source records attributed to L Krey.

At least 19 recordsLinked to original sources

PubMed2001

Preimplantation genetic diagnosis (PGD), a collaborative activity of clinical genetic departments and IVF centres.

Preimplantation genetic diagnosis (PGD) requires the combined efforts of geneticists and workers in the field of reproductive medicine. This was studied on the basis of a questionnaire, sent to 35 members of the PGD Consortium of the European Society of Human Reproduction and Embryology (ESHRE). A reply was obtained from 20 centres. They represent the majority of activities in the field of PGD in the world. It is obvious that many of the activities (in vitro fertilisation, embryo culture and biopsy) take place in IVF units while others (counselling and diagnosis) are the responsibility of genetic diagnostic centres. The distances between both units vary considerably. In all but one centre sex determination is offered. Aneuploidy screening is offered in 13 out of 20 centres. PGD of translocations and other structural chromosome abnormalities is offered in all but one centre. The number of monogenic diseases offered varies considerably. In comparison to prenatal diagnosis PGD is more expensive. The majority of these costs are due to the IVF or ICSI procedure. The charges for PGD vary between about 600 euro and 4000 euro. In 16 out of 20 centres the parents to be must sign an informed consent form.

Aneuploidy↗

PubMed2001

A two- versus three-embryo transfer: the oocyte donation model.

OBJECTIVE: To compare implantation and pregnancy rates in oocyte recipients undergoing a two-embryo versus three-embryo transfer, 3 days after retrieval. DESIGN: Retrospective comparative analysis. SETTING: University-based in vitro fertilization center. PATIENT(S): All oocyte recipients undergoing embryo transfer from January 1, 1997 through August 31, 1999. INTERVENTION(S): Recipients received two or three embryos. MAIN OUTCOME MEASURE(S): Implantation, and clinical and multiple pregnancy rates. RESULT(S): Seventy-three recipients underwent a two-embryo transfer, and 376 had three embryos replaced. The numbers of oocytes retrieved (12.7 +/- 0.89 vs. 13.1 +/- 0.36) and embryos obtained (8.05 +/- 0.65 vs. 8.77 +/- 0.27) did not differ between the two-embryo and three-embryo transfer groups, nor did the proportion of patients with embryo cryopreservation (54.3% vs. 42.6%, respectively). There was no significant difference in pregnancy or implantation rates when comparing those patients with a two-embryo transfer to those with a three-embryo transfer. Significantly, 13.8% of the pregnancies in the three-embryo transfer group were triplet. CONCLUSION(S): Reducing the number of embryos transferred in an oocyte donation cycle can lower the incidence of triplet pregnancies without significantly lowering the overall pregnancy rate.

Cryopreservation↗

PubMed2001

Factors useful in predicting the success of oocyte donation: a 3-year retrospective analysis.

OBJECTIVE: To establish prognostic relevance of parameters assessed in oocyte donation cycles. DESIGN: Retrospective analysis. SETTING: Large university-based donor oocyte program. PATIENT(S): All oocyte recipient cycles achieving embryo transfer from September 1995 to October 1998. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Pregnancy. RESULT(S): Recipient age and reproductive status, day 9 and 12 serum estradiol (E(2)) levels and a progesterone (P) level obtained 2 days after initiation of hormonal therapy did not correlate with pregnancy. Endometrial thickness, but not endometrial pattern, was useful in predicting pregnancy outcome. The clinical pregnancy and live-birth rate in cycles where the endometrial thickness was less than 8 mm was significantly lower when compared to cycles with an endometrial thickness > or =9 mm. Cycles where optimal quality embryos were transferred had the highest implantation (36%), clinical pregnancy (63%) and live birth (54%) rates and these rates were significantly higher than those of cycles where only poor quality embryos were available for transfer (10% implantation, 17% clinical pregnancy, and 8% live birth rates, respectively; P<.05). CONCLUSION(S): The most reliable predictive factors for pregnancy in oocyte donation cycles are the quality of the embryos transferred and the recipient's mid-cycle endometrial thickness. Recipient monitoring should minimally include ultrasound assessment of endometrial thickness.

Adult↗

PubMed2001

Fertility and maternal age strategies to improve pregnancy outcome.

In humans, the live birth rate drops precipitously with increasing maternal age, and this decline is associated with increases in the incidence of oocyte and embryo aneuploidy. Preimplantation aneuploidy screening has improved pregnancy outcome by significantly lowering the miscarriage rate. Nevertheless, aneuploidy screening only identifies the affected embryos; it does not attempt to correct the underlying biologic problem. Anomalies in chromosome segregation can result from a dysfunctional first or second meiotic division in the egg or develop after fertilization during the first few mitoses of early embryonic development. In both instances, ooplasmic anomalies may account for the nuclear problem. Low cell levels of cytoplasmic proteins (e.g., cytoskeletal elements, enzymes, energy stores, cell cycle regulatory proteins) may lead to a dysfunctional division of chromosomes during egg maturation or following fertilization. Ooplasmic injection is a micromanipulation technique that has produced pregnancies in patients with a history of poor-quality, fragmented embryos. Germinal vesicle transfer is a research procedure used to investigate the ooplasmic-nuclear interplay regulating cell cycle, maturation, and fertilization. Both these techniques may prove to be effective in improving the quality of eggs from patients of advanced maternal age.

Adult↗

PubMed2000

Preimplantation genetic diagnosis in two families at risk for recurrence of Herlitz junctional epidermolysis bullosa.

The Herlitz type of junctional epidermolysis bullosa (H-JEB) is a severe inherited bullous disease which leads to the early demise of the affected newborn. Mutations in the genes encoding the 3 polypeptides of the anchoring filament protein laminin 5 underlie this condition. We studied 2 families with affected children who previously died from H-JEB. Mutation screening using heteroduplex analysis and direct sequencing of the PCR products revealed a previously described hotspot mutation in LAMB3 (R635X), and a novel delayed termination codon in LAMB3 in the first proband. In the second proband, we found a novel initiation codon mutation in LAMB3, and a novel 2 bp deletion in LAMB3. For preimplantation genetic diagnosis (PGD) in these families, we developed nested multiplex PCR assays, amplifying the mutations and informative intragenic polymorphisms in the probands. Single embryonic cells were biopsied from 8-cell embryos using standard techniques, and subjected to the multiplex PCR assay followed by restriction enzyme digestion. Embryos found not to carry either mutation were transferred to the mothers, and a pregnancy was established in the second family as evidenced by the elevated level of HCG, although the pregnancy did not persist. This study illustrates the feasibility of PGD for an inherited skin disorder for the first time.

Base Sequence↗

PubMed1999

Enhancement or initiation of testicular sperm motility by in vitro culture of testicular tissue.

OBJECTIVE: To describe different techniques of testicular tissue culture and their effect on sperm motility, mainly in cases of totally immotile spermatozoa, and to compare the effect of in vitro culture with that of motility stimulants. DESIGN: Prospective study. SETTING: University teaching hospital. PATIENT(S): Ten patients undergoing testicular biopsy for diagnostic purposes or for intracytoplasmic sperm injection. INTERVENTION(S): Dissected testicular biopsy samples and tissue blocks were cultured at 37 degrees C for up to 96 hours. Immediately after dissection, immotile testicular spermatozoa were incubated for 30 minutes in pentoxifylline and 2-deoxyadenosine. MAIN OUTCOME MEASURE(S): Sperm motility and vitality. RESULT(S): Overall, dissected samples showed improved sperm motility, which peaked within 48 hours of culture. Unlike motility, vitality declined linearly, from 56.3%+/-19% at initial assessment to 18.8%+/-11% at 96 hours. Five samples had initially immotile spermatozoa, of which four acquired motility at 48 hours. In vitro culture showed results comparable with those of incubation with pentoxifylline and 2-deoxyadenosine. Culture of tissue blocks did not improve motility or vitality compared with dissected tissue. CONCLUSION(S): The motility of testicular spermatozoa was enhanced or initiated after in vitro culture. Testicular biopsy culture may be an alternative to the use of motility stimulants to obtain motile spermatozoa for intracytoplasmic sperm injection, particularly when oocytes are not immediately available.

Adult↗

PubMed1999

Elevated day 3 serum follicle stimulating hormone and/or estradiol may predict fetal aneuploidy.

OBJECTIVE: To determine whether baseline serum FSH and/or E2 concentrations can predict the risk for fetal chromosomal abnormalities. DESIGN: Case control study. SETTING: Reproductive technology program at a university hospital. PATIENT(S): Patients who underwent dilation and curettage (D + C), and whose products of conception were karyotyped. INTERVENTION(S): Patients underwent natural conception or controlled ovarian hyperstimulation followed by intrauterine insemination, in vitro fertilization and embryo transfer, gamete intrafallopian transfer, or zygote intrafallopian transfer. MAIN OUTCOME MEASURE(S): Baseline serum FSH and E2 concentrations and fetal karyotype. RESULT(S): Genetic evaluation of 78 D + C specimens revealed 34 normal and 44 abnormal fetal karyotypes. A significantly greater proportion of women with abnormal fetal karyotype had elevated baseline serum FSH (> or =15 mIU/mL [RIA] or 10 mIU/mL [Immulite]) and/or E2 > or = 50 pg/mL [Immulite]) compared with women of normal fetal karyotype. Among karyotypically abnormal abortuses, autosomal trisomy was the most common abnormality noted (79.5%), followed by mosaicism (6.8%), triploidy (6.8%), monosomy XO (4.5%), and balanced translocation (2.3%). CONCLUSION(S): Baseline serum FSH and/or E2 concentrations may be valuable as predictors of fetal aneuploidy.

Abortion, Missed↗

PubMed1999

In vitro maturation of human preovulatory oocytes reconstructed by germinal vesicle transfer.

OBJECTIVE: To describe a micromanipulation-electrofusion procedure for transferring germinal vesicles (GVs) between immature human oocytes. DESIGN: Pilot study to assess oocyte maturation after an invasive micromanipulation procedure. SETTING: Research laboratory at a university medical center. PATIENT(S): Immature oocytes were discarded from intracytoplasmic sperm injection (ICSI)-IVF cycles of patients 23-48 years of age. INTERVENTION(S): Initially, GV removal and transfer were performed on the same oocyte; these "self-reconstructed" oocytes were then cultured in vitro for up to 50 hours and examined periodically for maturation as judged by the extrusion of the first polar body. In a second study, GVs from oocytes of "old" patients (>38 years old) were successfully transferred into enucleated immature oocytes of "young" patients (<31 years old). MAIN OUTCOME MEASURE(S): Extrusion of the first polar body was monitored in "reconstructed" and control oocytes; karyotypes also were analyzed at meiosis II. RESULT(S): From 48 oocytes from old patients, 12 GVs were successfully removed, transferred, and fused into previously enucleated oocytes from young patients. After in vitro culture, 7 of these "reconstructed" oocytes matured to meiosis II, a maturation rate not significantly different from that observed in nonmanipulated controls. A normal, second meiotic metaphase chromosome complement was observed in 4 of 5 reconstructed oocytes. CONCLUSION(S): Normal meiosis can occur after the transfer of a GV into an enucleated host oocyte. Germinal vesicle transfer may be a valuable research procedure that generates cell models to characterize the cytoplasmic-nuclear interplay for cell cycle regulation, maturation, and fertilization in the human oocyte; it also may be a potentially attractive alternative to oocyte donation.

Adult↗

PubMed1999

In vitro fertilization outcome relative to embryo transfer difficulty: a novel approach to the forbidding cervix.

OBJECTIVE: To assess the impact of ET difficulty on IVF outcome and to optimize the ET procedure. DESIGN: Retrospective analysis of IVF outcome by ET catheter type and ET difficulty. Prospective treatment and follow-up of patients with a history of extremely difficult cervical passage. SETTING: Large university-based IVF program. PATIENT(S): All patients < 40 years of age undergoing IVF-ET from September 1995 to May 1998. INTERVENTION(S): Surgical correction of cervical stenosis. MAIN OUTCOME MEASURE(S): Pregnancy and embryo implantation rates. RESULT(S): Only 0.6% of ETs were "extremely difficult." Pregnancy rates were not statistically significantly different among ETs graded easy, moderate, and difficult. In contrast, no pregnancies occurred in the rare "extremely difficult" ET group. Eight patients with a history of extremely difficult cervical passage underwent surgical correction of their cervical stenosis. Twelve postoperative IVF-ET in these women resulted in eight clinical pregnancies, six of which were multiple gestations. The embryo implantation rate of these cycles was 42.2%. CONCLUSION(S): Patients with a history of extremely difficult ET may benefit from hysteroscopic evaluation and possible modification of their cervical canal before a future IVF attempt.

Adult↗

PubMed1997

Update in preimplantation genetic diagnosis. Age, genetics, and infertility.

PGD has been successfully used for several years. Over 40 babies have been born worldwide by use of these techniques. Unfortunately, a number of misdiagnoses have been made, a distressing consequence of a new frontier. Significant advances have been made to improve the efficiency and accuracy of PCR and FISH. The widespread use of this technology awaits further documentation of safety and accuracy. Other issues must also be addressed. First, the cost-effectiveness of the techniques relative to the traditional alternatives must be evaluated. A number of ethical issues regarding embryo screening must be addressed including what diseases are serious enough to warrant the procedure. Another concern is the use of this technology for nongenetic disorders such as gender selection. Finally, the experimental nature of these procedures must continually be discussed with patients, and long-term follow-up studies must be undertaken. Development of more accurate and less expensive assays coupled with improved IVF success rates may make PGD a more widely used clinical tool. The future awaits these developments.

Age Factors↗

PubMed1997

Alterations in steroid hormone receptors in the tamoxifen-treated endometrium.

OBJECTIVE: Our purpose was to evaluate whether tamoxifen has estrogenic endometrial effects as defined by histologic study or alterations in steroid hormone receptor expression. STUDY DESIGN: Nineteen postmenopausal tamoxifen-treated breast cancer patients who also had endometrial sampling were identified from files in the Department of Obstetrics and Gynecology. To examine the subgroup of 15 polyps, age-matched, non-hormonally treated patients with polyps (n = 8) or atrophic endometria (n = 5) served as comparison groups. Proliferative (n = 3) and secretory (n = 5) endometria served as procedural controls. Immunohistochemical studies for steroid receptors (estrogen, progesterone) were performed. RESULTS: Glandular cell progesterone receptor was significantly increased and stromal cell estrogen receptor was significantly decreased in tamoxifen-treated versus atrophic endometria. Progesterone receptor staining was not significantly different in tamoxifen-treated versus control polyps, although staining was high in both groups. Stromal cell estrogen receptor staining was significantly reduced in tamoxifen-treated versus control polyps, although there were no histologic differences. Reduced stromal cell estrogen receptor and increased glandular cell progesterone receptor staining was found in all tamoxifen-treated endometria regardless of the diagnosis. CONCLUSION: The tamoxifen-associated changes in endometrial steroid receptors support an estrogenic effect that is independent of histologic diagnosis and duration of use. This may contribute to the pathogenesis of tamoxifen-associated polyps and carcinomas.

Aged↗

PubMed1997

The embryo versus endometrium controversy revisited as it relates to predicting pregnancy outcome in in-vitro fertilization-embryo transfer cycles.

To evaluate embryonic and endometrial factors for their value in predicting pregnancy outcome in in-vitro fertilization (IVF) and embryo transfer, a retrospective data collection and prospective uterine artery colour Doppler imaging study was performed in a university-based IVF-embryo transfer programme setting. A total of 210 patients were included and grouped as follows: (I) IVF with controlled ovarian stimulation (214 cycles); (II) frozen-thaw cycle of autologous embryos (30 cycles); (III) oocyte donation, no cryopreservation (12 cycles); (IV) frozen-thaw cycle with embryos from donated oocytes (10 cycles). Embryo quality was significantly better in pregnant than non-pregnant cycles (group I, P = 0.0104; groups II-IV, P = 0.0418). The endometrial echo was significantly thicker in pregnant versus non-pregnant patients in group I (P = 0.0059), but not in groups II-IV (P = 0.741). Past uterine surgery or abnormalities had no effect on pregnancy outcome. There were no significant differences in mean uterine artery resistance index or peak systolic velocity in pregnant versus non-pregnant patients in groups II-IV. Thus, embryo quality is the most reliable predictor of pregnancy outcome. Endometrial measurements were significantly thicker in subsequently pregnant patients only in group I, where the endometrium reflects the hormonal environment. Doppler parameters were not useful in predicting pregnancy outcome.

Arteries↗

PubMed1997

A simple and objective approach to identifying human round spermatids.

Although round spermatids have been studied extensively using staining techniques and electron microscopy, little information is available about their appearance in living conditions. We describe a method of collecting and identifying round spermatids from ejaculates and testicular biopsies. The validity of the selection procedure was confirmed by fluorescence in-situ hybridization. Based on cell size, morphological characteristics of nucleus and cytoplasm, and on the nucleus/cytoplasm ratio, we harvested a population of cells that was 84% haploid. This procedure can be applied to select spermatids for clinical or research purposes.

Biopsy↗

PubMed1997

Alterations in endometrial stromal cell tissue factor protein and messenger ribonucleic acid expression in patients experiencing abnormal uterine bleeding while using Norplant-2 contraception.

A high incidence of irregular uterine bleeding is the primary patient complaint limiting the utility of long term, progestin-only contraceptive agents such as Norplant. The onset of hemorrhage requires both inadequate hemostasis and impaired vascular integrity. Thus, we first tested whether Norplant-associated endometrial bleeding was accompanied by altered expression of perivascular stromal cell tissue factor (TF), the primary initiator of hemostasis. Norplant effects on TF messenger ribonucleic acid (mRNA) and protein expression by endometrial stromal cells were assessed by in situ hybridization and immunohistochemical examination of endometrial biopsies obtained from normally cycling control women (n = 14) and from patients experiencing Norplant-induced abnormal uterine bleeding (n = 24). TF mRNA and protein expression was increased 150% in secretory vs. proliferative phase endometrial specimens. By contrast, endometrial TF mRNA and protein levels were reduced during 1-6 months of Norplant treatment by about 2-fold (P < 0.05 for protein) compared to the values for control secretory phase specimens. These changes were consistent with observations that patients on Norplant begin to bleed during this interval. Further reductions of TF mRNA and protein levels to 2- and 3-fold of those in secretory phase control specimens were observed in endometria obtained after 6-12 months of Norplant therapy (P < 0.05 and P < 0.01, respectively). A modest rebound in TF mRNA and protein expression was observed after 12 months of Norplant therapy, which occurred commensurate with reduced patient complaints of abnormal uterine bleeding. Pathologically enlarged venous sinusoids were ubiquitous in endometrial specimens obtained after Norplant therapy. The combination of fragile blood vessels and reduced TF expression may account for bleeding in patients receiving Norplant therapy.

Contraceptive Agents, Female↗

PubMed1996

Thyroid hormone and estrogen interact to regulate behavior.

Environmental perturbations that increase plasma thyroid hormone (T3) concentrations also profoundly affect female reproductive behavior and physiology. We explored whether these effects were mediated by interactions between T3 receptor (TR) and estrogen receptor (ER). This hypothesis was of interest because the half-site of a consensus T3 response element DNA sequence is identical to an ER response element (ERE), and TRs bind to a consensus ERE. Molecular data presented in the accompanying paper [Zhu, Y.-S., Yen, P.M., Chin, W.W.& Pfaff, D.W. (1996) Proc. Natl. Acad. Sci. USA 93, 12587-12592] demonstrate that TRs and ERs are both present in rat hypothalamic nuclear extracts and that both can bind to the promoter the hypothalamic gene preproenkephalin and that interations between liganded TRs and ERs affect preproenkephalin transcription. In this paper, we show that molecular interactions between TRs and ERs are sufficient to mediate environmental effects on estrogen-controlled reproductive behavior. Ovariectomized (OVX) rats treated with high doses of T3 showed significantly lower levels of lordosis behavior in response to estradiol benzoate (EB) compared with OVX females treated with EB alone. Conversely, thyroidectomized/OVX females treated with EB showed significantly greater levels of lordosis behavior compared with OVX females treated with EB, showing the effect of endogenous T3. Thyroid hormone interference with EB-induced behavior could not be explained by a reduction in plasma E2 concentrations or by a general reduction in responsiveness of EB-sensitive tissues. Moreover, numbers of hypothalamic ER-immunoreactive cells increased dramatically following T3 treatment. These data suggest that T3 may reduce EB-dependent sexual behavior through interactions between TR and ER in the nuclei of behaviorally relevant hypothalamic neurons, envisioning for the first time a functional consequence of interactions between two nuclear hormone receptors in brain. These results also open up the possibility of molecular interactions on DNA encoding environmental signals, a new field for the study of neuronal integration.

Animals↗

PubMed1996

Update in preimplantation genetic diagnosis: successes, advances, and problems.

The field of preimplantation genetic diagnosis has undergone significant advances since the report of the first birth from this method in 1990. The first birth in the USA was reported in 1992, as was the first successful diagnosis and delivery of a baby free of a single gene defect disorder (cystic fibrosis and then Tay Sachs). Investigators have now reported approximately 40 births worldwide from preimplantation genetic diagnosis using the polymerase chain reaction and fluorescent in-situ hybridization methods to analyze single cells removed from early cleavage stage preimplantation embryos. The International Working Group on Preimplantation Genetics meets annually to discuss progress and pitfalls in this field. Although preimplantation genetic diagnosis offers hope to patients at risk of transmitting disease, there are many technical hazards of this experimental procedure. Technical difficulties must be overcome in order for preimplantation genetic diagnosis to become a standard clinical tool. This review will highlight some of the recent advances and problems in the field of preimplantation genetic diagnosis.

Age Factors↗

PubMed1995

Preliminary observations on the use of midodrine in treating orthostatic hypotension in familial dysautonomia.

Midodrine, a peripheral alpha-adrenergic agonist, was evaluated in 7 female and 2 male patients with familial dysautonomia (FD), a disorder characterized by decreased sympathetic innervation. Prior to and after three months of midodrine treatment, each patient's response to postural change was assessed by arteriosonde readings of blood pressure and heart rate, corrected QT-interval measurements, Doppler evaluation of renal blood flow and circulating atrial natriuretic peptide (ANP) levels. The initial midodrine dose (2.5 mg three times daily) was raised until subjective symptoms improved. Doses were reduced if patients felt jittery or developed erect hypertension (systolic > 180 mmHg or diastolic > 110 mmHg). Midodrine, at an average dose of 0.25 mg/kg per day, improved subjective symptoms in all patients. With treatment, magnitude of blood pressure responses was variable. Although mean erect blood pressure did not increase significantly for the aggregate, it did increase in six of nine patients. In addition, the QTc interval normalized and erect renal perfusion improved. Changes in supine mean blood pressure and supine circulating ANP correlated directly. We judge midodrine to be useful in management of orthostatic hypotension in patients with familial dysautonomia.

Adolescent↗

PubMed1994

Atrial natriuretic peptide response to postural change and medication in familial dysautonomia.

Circulating atrial natriuretic peptide (ANP) was assayed before and after postural change and exercise in 54 patients with familial dysautonomia (FD) and 20 controls. ANP levels were compared with blood pressure, heart rate, plasma catecholamines and parameters of renal function. Compared with controls supine FD subjects had elevated blood pressures, heart rates and ANP levels (39 +/- 4 pg/ml vs. 23 +/- 3 pg/ml, p < 0.01). With the erect posture and exercise in FD subjects, blood pressure fell below control values, with ANP lowered. In FD subjects, blood pressure was correlated with ANP levels when supine and when erect and with heart rate post exercise. In controls, ANP levels did not correlate with other parameters. In FD patients on metoclopramide, supine and erect blood pressure and ANP levels were higher. FD subjects treated with fludrocortisone, had elevated supine and erect noradrenaline (p < 0.05 and p = 0.06); and those on diazepam had lower erect and post exercise noradrenaline (p < 0.05), but ANP levels were similar. In conclusion, sympathetic denervation may increase FD patients' responsiveness to other regulators of cardiovascular integrity, such as ANP. In addition, circulating ANP and catecholamines in FD subjects appear to be influenced by commonly used medications, such as metoclopramide.

Adolescent↗