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Biomedical subjects

A B Shewchuk

Publications and source records attributed to A B Shewchuk.

9 recordsLinked to original sources
PubMed2000

Spontaneous blastomere fusion after freezing and thawing of early human embryos leads to polyploidy and chromosomal mosaicism.

The incidence of blastomere fusion after cryopreservation of early human embryos (day 2 and day 3) was investigated using the standard propanediol technique. The process of fusion was observed in all developmental stages (from 2 to 10 cells) and the frequency of this event was 4.6% in day 2 (41/889) and 1.5% in day 3 (10/646) embryos that survived the thawing (embryos with 50-100% intact cells). Fusion of two, and occasionally of several, blastomeres resulted in the formation of multinucleated hybrid cells, which clearly indicated that the ploidy of these newly created cells had been altered. This event, depending on the number of fused cells per embryo, transformed the embryos into either entirely polyploid embryos (complete fusion at 2- or 3-cell stage) or into mosaics being a mixture of polyploid and normal cells. Chromosomal preparations of embryos affected by blastomere fusion indicated the presence of tetraploid mitotic plates. Also, fluorescence in-situ hybridization (FISH) analysis using DNA probes targeting unique sequences on chromosomes 9, 15, 17 and 22 indicated the existence of tetraploid and diploid fluorescence signals in the interphase nuclei within mosaics. Therefore, observations on live and fixed embryos suggested that tetraploid (4n) or hexaploid (6n) and tetraploid-diploid or more complex aberrations of ploidy might be formed as a consequence of blastomere fusion. Furthermore, this demonstrates that freezing and thawing may induce numerical chromosomal changes in human embryos.

Blastomeres↗
PubMed1984

The effect of multiparity on intrasellar prolactinomas.

A complete reassessment of ovulation, pituitary reserve and function, and sella turcica anatomy was carried out in nine multiparous patients with intrasellar prolactinomas to determine whether long-term bromocriptine therapy was required and to document the natural history of the disease after two or more pregnancies. After the last pregnancy, bromocriptine was discontinued and pituitary function and anatomy and prolactinoma activity were reassessed with documentation of ovulation (basal body temperature graphs and menstrual history), search for fat droplet-positive galactorrhea, pituitary fossa tomography, computerized tomographic scan, triple-bolus testing, and visual fields. These data were compared with a similar workup carried out prior to the first pregnancy. Three groups of eventual outcomes were identified radiologically. Anterior pituitary gland function and reserve remained normal in all, and no neurological sequelae were noted. Four patients did not require long-term treatment. A hypothesis of autoinfarction of the adenoma is raised, since three patients were shown to have empty sellae.

Adult↗
PubMed1984

Pregnancy outcome in 242 conceptions after artificial insemination with donor sperm and effects of maternal age on the prognosis for successful pregnancy.

Four hundred four treatment courses of artificial insemination with donor sperm were initiated in 330 couples. A treatment course was defined as completed if the patient conceived, failed to conceive after 12 cycles of artificial insemination with donor sperm, or dropped out of the program after at least one inseminated cycle. We have documented a 92.4% conception rate in patients who completed six treatment courses and 83.7% in those completing at least three treatment courses. Including all the patients who dropped out, 72.7% of all patients conceived. Spontaneous abortion occurred in 17.4%; three infants with major congenital defects were delivered and three indicated midtrimester abortions were performed. Our data demonstrate that the prognosis for successful artificial insemination with donor sperm is inversely related to advancing maternal age. Patients over age 35 had significantly lower conception rates; more insemination cycles were required per conception and the incidence of spontaneous abortion was related to the number of cycles required per conception.

Abortion, Spontaneous↗
PubMed1983

Efficacy of antibiotic therapy in preventing spontaneous pregnancy loss among couples colonized with genital mycoplasmas.

Evidence suggests that genital mycoplasmas play a role in spontaneous abortion, prematurity, and perinatal morbidity and mortality rate. Since these organisms are sensitive to antibiotics, three treatment regimens were assessed for efficacy in preventing spontaneous pregnancy loss. The pregnancy loss rate was significantly reduced from 96% to 47.4% among those treated with doxycycline prior to conception and to less than 20% among those treated with erythromycin stearate only during pregnancy or with both regimens. The reduction in pregnancy loss rate was independent of maternal age, the number of previous abortions, gestational age at abortion, or other minor abnormalities. Diagnosis and treatment of mycoplasma infection following a first or later pregnancy loss equally prevented spontaneous loss in the next pregnancy. These observations suggest that appropriate treatment of mycoplasma infection could also prevent recurrent spontaneous abortion syndrome in couples with positive cultures.

Abortion, Habitual↗
PubMed1983

Serologic evidence of ureaplasma urealyticum infection in women with spontaneous pregnancy loss.

Among 71 couples with histories of pregnancy wastage, 84.5% were colonized with Ureaplasma urealyticum and/or Mycoplasma hominis; whereas in couples with successful deliveries the incidence was 25.4%. The distribution of U. urealyticum and M. hominis was comparable in the fertile and infertile populations. Of women with positive cultures, 96% aborted, compared with an expected rate of 19% to 45%. Serologic studies revealed that, at delivery, 42.9% of infants of mothers with pregnancy losses had fourfold elevations in titers above the mothers' level compared with 15% of normal infants. Mothers with pregnancy wastage histories had elevated titers above their infants in 42.9% of cases compared with 10% of normal mothers. Thus, both mothers and fetuses had responded immunologically to the presence of U. urealyticum. When the mean antibody titers in the normal and pregnancy wastage groups were calculated for each ureaplasma serotype, the infants of mothers with pregnancy losses exhibited significantly elevated mean titers to serotypes 6 and 8, while the mothers had elevated mean titers to serotypes 4 and 8. These observations suggest that U. urealyticum causes infection in mothers and fetuses and that certain ureaplasma serotypes may be more pathogenic than others.

Abortion, Spontaneous↗
PubMed1980

Predicted ovulatory response to 2-brom-alpha-ergocryptine (CB-154) in amenorrhea-galactorrhea syndromes.

Adenohypophyseal function was evaluated in 20 consecutive patients with hyperprolactinemic amenorrhea-galactorrhea in an attempt to predict ovulatory response with 2-brom-alpha-ergocryptine (CB-154) therapy. Pituitary fossa tomography and response to insulin, thyrotropin-releasing hormone, and luteinizing hormone--releasing hormone were correlated with the return of ovulatory cycles. Fourteen of 15 patients demonstrating normal pretreatment sellar volume ovulated, compared with 0 of 5 showing increased volume. Thirteen of 14 with adequate adenophypophyseal reserve of growth hormone and luteinizing hormone ovulated, compared with 0 of 6 and 1 of 6, respectively, with inadequate reserve. Serum prolactin suppression to normal occurred in 19 of 20 patients but could not predict response. Only 2 of 10 patients receiving clomiphene citrate ovulated and neither conceived, while 8 of the 10 ovulated with CB-154 and 6 of 7 desiring pregnancy conceived. CB-154 is an effective "fertility drug" and response to therapy can usually be predicted.

Adult↗
PubMed1980

The effect of pregnancy on suspected pituitary adenomas after conservative management of ovulation defects associated with galactorrhea.

Thirty infertile patients with ovulation defects and galactorrhea conceived after medical therapy: four after clomiphene stimulation (with or without hCG) and 26 after receiving CB-154 (2-Br-alpha-ergocryptine or bromergocryptine). Pregnancies were followed closely; sellar tomography and perimetry were repeated at 36 weeks' and 8 weeks' post partum. One patient required transsphenoidal adenectomy because of acute pituitary enlargement. Two developed minimal asymptomatic fossa enlargement. Lactation was suppressed with Lactostat in the first eight patients delivered; hyperprolactinemia, amenorrhea, and galactorrhea recurred. Five of eight showed asymptomatic enlargement of the sella. Bromergocryptine was used to suppress lactation in the rest. Long-term bromergocryptine therapy resulted in the restoration of euprolactinemic ovulatory cycles in all patients. These data suggest that patients with ovulation defects associated with galactorrhea can conceive with medical therapy now available. However, there is a risk of significant pituitary enlargement during pregnancy and the puerperium. Lactation should be suppressed with bromergocryptine.

Adenoma↗
PubMed1976

Prolactin hypersecretion and short luteal phase defects.

The short luteal phase is commonly found in ovulating women presenting with infertility, or in amenorrheic women induced to ovulate with clomiphene. When the short luteal phase defect is accompanied by the discovery of galactorrhea, the two abnormalities may share a common underlying cause. Two cases are presented to demonstrate the short luteal phase defect as one early manifestation that may occur during the development of the amenorrhea-galactorrhea syndrome. Antiprolactin therapy may cause this menstrual disorder to revert to normal, allowing normal fertility and terminating the galactorrhea.

Adult↗