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Biomedical subjects

B D Cowan

Publications and source records attributed to B D Cowan.

At least 55 records · Page 3Linked to original sources
PubMed1994

Determination of fetal acidemia at birth from a remote umbilical arterial blood gas analysis.

OBJECTIVE: Sampling of the umbilical artery for determination of acid-base status is performed within 60 minutes of birth, but is not feasible in all hospitals on a 24-hour basis. A desirable alternative would be to perform the arterial cord blood gas analysis hours after the sample was obtained at delivery with reliable identification of whether the newborn was acidotic. STUDY DESIGN: After 19 deliveries multiple umbilical arterial blood samples were withdrawn into five preheparinized syringes, and these were analyzed at 0.5, 15, 30, 45, and 60 hours after delivery. On the basis of observed changes in pH and base deficit over 60 hours, two separate regression equations were generated. These two equations permit calculation of the original pH and base deficit if the following are known: (1) the time interval from delivery to blood gas analysis and (2) the values of the remote pH and remote base deficit. The regression models were validated among 23 subsequent deliveries to assess how accurately they identified newborn acid-base status at birth. RESULTS: The original pH and base deficit can be calculated with two separate equations from linear regression models if two variables are known: the results of the remote umbilical arterial blood gas analysis and time intervals from delivery to analysis. Of 23 newborns during the validation phase of the study, 16 were not acidotic, one had respiratory acidosis, and six had metabolic acidosis. The second umbilical arterial blood gas analysis was performed at a mean (+/- SD) interval of 53.8 +/- 41.5 hours (range 7.5 to 138 hours). The remote gas analysis inaccurately identified 68.7% (11/16) of nonacidotic newborns as being acidotic at birth. However, insertion of these data into these equations produced results with none of the newborns predicted to have normal acid-base when they were acidotic at birth or predicted to be acidotic when the cord pH was normal. CONCLUSIONS: Use of these mathematic models allows the clinician to perform an umbilical arterial blood pH analysis < or = 60 hours after delivery yet with accurate estimation of true acid-base status at birth.

Acidosis↗
PubMed1994

First-trimester rapid semiquantitative assay for urine pregnanediol glucuronide predicts gestational outcome with the same diagnostic accuracy as serial human chorionic gonadotropin measurements.

OBJECTIVE: The purpose of this study was to compare a single urine pregnanediol glucuronide measurement with serial human chorionic gonadotropin titers for the prediction of abnormal early gestations. STUDY DESIGN: We analyzed multiple urine pregnanediol glucuronide levels in 19 spontaneously conceived pregnancies during the first 49 days of gestation. A semiquantitative measurement was made by rapid enzyme immunoassay (Phase Check) at different urinary dilutions. To establish the reliability of semiquantitative urine pregnanediol glucuronide assay to detect abnormal gestation, this test was compared with human chorionic gonadotropin doubling times derived from a previously described normal population. A receiver-operator characteristic curve was constructed for each test, and areas under the curve with corresponding SEs were calculated. The critical-ratio z test was used to compare the two assays. RESULTS: The receiver-operator characteristic curves indicate that both urine pregnanediol glucuronide and human chorionic gonadotropin doubling can predict early gestational complications (p < 0.05). The area under the curve for human chorionic gonadotropin doubling time was 0.809 +/- 0.048, and urine pregnanediol glucuronide had an area of 0.702 +/- 0.072. Comparison of the area under the curve revealed that the ability of urine pregnanediol glucuronide to predict early gestational failure was indistinguishable from that of human chorionic gonadotropin doubling times (p > 0.05). A 1:2 dilution of urine gave the best results in the semiquantitative urine pregnanediol glucuronide test (Phase Check). CONCLUSIONS: On the basis of receiver-operator analysis, semiquantitative urine pregnanediol glucuronide measurements predict abnormal early gestations as well as serial human chorionic gonadotropin measurements do. The ability of a single urine semiquantitative assay (Phase Check) to predict early gestational complications offers a convenient screening tool that may identify women with abortive or ectopic pregnancies before the onset of symptoms.

Abortion, Spontaneous↗
PubMed1993

Parturitional factors associated with membrane stripping.

OBJECTIVE: Our purpose was to determine what factors occurring after digital separation of the chorionic membranes from the lower uterine segment (membrane stripping) are involved in observed clinical changes compared with patients not so treated. STUDY DESIGN: Thirty patients were randomly divided among a study population and two control groups to assess uterine contractions and microbiologic, histologic, and biochemical markers associated with parturitional events over a 7-hour time frame. RESULTS: Clinically, an increased frequency of uterine contractile activity was observed among patients in the membrane-stripped group (p < 0.03). There was a significant increase in plasma 13,14-dihydro-15-keto-prostaglandin F2 alpha (p < 0.001) and endocervical phospholipase A2 activity (p < 0.04) among those who underwent membrane stripping. Blood leukocyte counts, sedimentation rates, prostaglandin E2 metabolite concentrations, and fibronectin levels revealed no significant change during the 7-hour study session. CONCLUSION: Membrane stripping was associated with increases in phospholipase A2 activity and prostaglandin F2 alpha concentrations, indicating a possible correlation with initiation of the cascade of parturitional events.

Amnion↗
PubMed1993

Ectopic pregnancy.

The incidence of ectopic pregnancy in the United States is increasing annually and is approaching epidemic proportions. Serum progesterone measurements show promise for the early detection of abnormal gestational development. Unfortunately, examination of serum progesterone levels does not allow discrimination between an ectopic pregnancy and an intrauterine abortion. Additionally, discriminatory levels of progesterone fail to include all abnormal gestations in the abnormal group (false-negative result) and classify some normal pregnancies to the abnormal group (false-positive result). As such, no discriminatory level of progesterone has been identified that can diagnose abnormal gestations. Instead, the value of progesterone appears to be its ability to predict a gestational complication, in much the same fashion as human chorionic gonadotropin doubling times. The advantage of progesterone appears to be that a single test of serum progesterone during the first 8 weeks of pregnancy is as predictive as serial human chorionic gonadotropin measurements. Clearly, future investigations into early gestational complications will focus on testing procedures that can discriminate between an intrauterine first-trimester demise and an ectopic pregnancy. Medical treatment for ectopic pregnancy is dependent on early diagnosis and is not yet widespread. Prostaglandin F2 alpha and methotrexate continue to be effective agents and demonstrate approximately 95% efficacy. Reproductive performance after medical therapy is comparable to reproductive performance after surgical therapy, but the duration of time until cure is longer in patients treated medically than in those treated surgically. Nomograms for human chorionic gonadotropin surveillance after surgical treatment have now been described, but not such data exists for surveillance after medical therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Chorionic Gonadotropin↗
PubMed1992

Receiver-operator characteristic, efficiency analysis, and predictive value of serum progesterone concentration as a test for abnormal gestations.

OBJECTIVE: Our objective was to determine if a discriminatory progesterone concentration could be established that confidently predicted abnormal early gestations. STUDY DESIGN: We analyzed differences in progesterone concentrations between normal (n = 40) and abnormal (n = 34) pregnancies during the first 49 days of gestation. The receiver-operator characteristic curve, test efficiency, and predictive value of serum progesterone to discriminate between an abnormal and normal first-trimester gestation were calculated for progesterone concentrations between 5 and 25 ng/ml. RESULTS: Receiver-operator characteristic curve analysis indicated that the best discriminatory progesterone concentration was 10 ng/ml. Test efficiency was maximum between serum progesterone concentration of 9 to 14 ng/ml (80%). When progesterone was less than 10 ng/ml, the predictive value of the abnormal test result was greater than 90%. CONCLUSION: Receiver-operator characteristic analysis, test efficiency, and the predictive value of an abnormal test result suggest that the best progesterone cut off point that predicts abnormal early pregnancies is 10 ng/ml.

Abortion, Spontaneous↗
PubMed1992

Treatment of unruptured ectopic pregnancy with methotrexate.

Medical treatment is appropriate for patients with an unruptured tubal pregnancy who wish to preserve fertility or have medical problems associated with increased risk of anesthesia. Patients with persistent trophoblast after conservative surgery should be treated with methotrexate rather than undergo a repeat surgery. All nine of our patients with ectopic pregnancies who were treated with MTX were cured with one course of therapy. Little toxicity was observed and subsequent reproductive performance after medical treatment was comparable to that reported in the literature. Direct injection of MTX into an ectopic pregnancy under sonographic control provided an option for treatment which required little anesthesia, reduced the amount of drug and allowed the treatment of a gestation which would otherwise not be considered a candidate for the 3 dose intramuscular injection protocol (see Table 3).

Female↗
PubMed1991

Benign symptomatic hyperandrogenism in a postmenopausal woman.

Hyperandrogenemia in postmenopausal women requires an evaluation to exclude pathologic ovarian or adrenal causes. Our patient exhibited no signs of hypercortisolism, congenital adrenal hyperplasia, or adrenal or ovarian neoplasia based on biochemical testing and pelvic sonography. We hypothesized that unexplained androgen excess in our patient was due to the development of gonadotropin-dependent excess ovarian stromal androgen production. This syndrome may be comparable to gestational hyperreactio luteinalis where elevated gonadotropins stimulate ovarian stromal androgen production. If tumor can confidently be excluded, such women may benefit from gonadotropin suppression with long-acting GnRH-a.

Aged↗
PubMed1990

Hydatidiform mole pregnancy trophoblast extracts differentially suppress interleukin-2-induced proliferation of human T-lymphocytes and PHA-blasts.

Immunoregulatory factors of trophoblast origin may partially abrogate maternal immune responses to the fetus during pregnancy. We have previously shown that soluble factors extracted from hydatidiform mole trophoblast suppress interleukin-2 (IL-2)-dependent proliferation of a cloned murine cytotoxic T cell line (CTLL-2). To characterize human T cell responses to this trophoblast extract, we measured the effects of molar tissue extracts (HME) on IL-2-stimulated proliferation of human T-lymphocytes and mitogen (PHA) transformed T-cell blasts (PHA-blasts). HME significantly (P less than 0.05) suppressed T-lymphocyte proliferation in response to 5 and 10 units/ml of IL-2 at 500 and 250 micrograms/ml, while no effect was observed at the 100 micrograms/ml concentration. Suppression by HME of IL-2-stimulated T-cell proliferation was partially overcome by the addition of excess IL-2. HME also suppressed (P less than 0.05) IL-2-stimulated proliferation of PHA-blasts at 500 and 250 micrograms/well at both 5 and 10 units/ml of IL-2. As observed with resting T-cell responses, no suppression of PHA-blast proliferation was observed using 100 micrograms/ml of HME. In contrast to the response of the resting T-cells to excess IL-2, HME suppression of IL-2-stimulated blast proliferation was not affected by increasing the concentration of IL-2. These results indicate that extracts from hydatidiform mole trophoblast contain immunosuppressive factors that block human T-cell clonal expansion by inhibiting the utilization and/or production of IL-2. Furthermore, the effects of HME are not reversed by excess IL-2 when PHA-blasts are reacted compared to resting T-cell responses, which are partially reversed in the presence of excess IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Survival↗
PubMed1990

Biochemical assessment and prediction of gestational well-being.

It is apparent from this brief review of serum markers that there is no ideal biochemical screen available to either assure fetal well-being or reliably predict fetal compromise. At present, MSAFP has become the dominant serum marker, but much work needs to be done to refine its usefulness as a screen and its utility in association with other measurements of fetoplacental well-being. The trend in modern obstetric management is toward an array of biophysical tests of fetal well-being, particularly in the last trimester of pregnancy. Biochemical screening in early gestation is used increasingly to assess future fetoplacental status and to predict risk for later pregnancy complications. Combinations of these biochemical and biophysical modalities will likely achieve the greatest predictive success in assessing fetal and placental well-being.

Atrial Natriuretic Factor↗
PubMed1990

Abnormal bleeding in the climacteric.

In the perimenopausal years, we encounter a situation where the normal diminution in reproductive capacity, with its resulting disruption of the normal menstrual hormonal pattern, coincides with a very real risk of pelvic pathology. Limitation in the ability to diagnose and to treat these patients conservatively has in the past resulted in a high rate of hysterectomy. With increased understanding of the normal physiology of this stage of transition and with improved diagnostic tools, we are now able to come to a definitive diagnosis in most patients. This ability to assure the diagnosis has made it much easier to counsel the patient confidently about the appropriate course of action. We will continue to encounter the problem of hysterectomy for bleeding with no histologic lesion being found. Although reviewers' letters may be considered an unnecessary thorn in the side, the improved practice that has resulted from these efforts gives strong support to their continued activities. We can have confidence that our treatment plan evolved in a logical manner and offers our patients a high probability of benefit at justifiable risk.

Climacteric↗
PubMed1989

Suppression of lymphocyte proliferation in vitro by macromolecules in the vesicle fluid and tissue extracts of hydatidiform mole.

This study examines the effects of vesicle fluid and tissue extracts from hydatidiform mole trophoblast on lymphocyte proliferation in vitro. Samples were obtained by direct aspiration of vesicles (hydatidiform mole vesicle fluid (HMF] or homogenization of molar tissues (hydatidiform mole extract (HME] following therapeutic uterine evacuation of hydatidiform mole. Dialyzed and lyophylized HMF pooled from two patients exhibited a 30% suppression (P less than 0.05) of mitogen-induced lymphocyte proliferation at a concentration of 12.5 micrograms protein/ml. Similarly, lymphocyte transformation was significantly suppressed (P less than 0.05) by HME at concentrations of 500 and 250 micrograms/ml. Molecular weight chromatography of HME resolved 4 protein fractions. Fraction 3 (35--50 kDa) and fraction 4 (less than 35 kDa) significantly suppressed mitogen-induced lymphocyte transformation while fractions 1 and 2 demonstrated no immunosuppression. Heat treatment (56 degrees C, 30 min) abolished the immunosuppressive activity of HME as well as fractions 3 and 4. These results suggest that hydatidiform mole trophoblast contains heat-labile macromolecules which suppress mitogen-mediated lymphocyte transformation. Such trophoblast-derived factors may interfere with maternal rejection of the allograft.

Female↗
PubMed1989

Bromocriptine inhibition of anesthesia-induced hyperprolactinemia: effect on serum and follicular fluid hormones, oocyte fertilization, and embryo cleavage rates during in vitro fertilization.

Thirty-two patients undergoing in vitro fertilization (IVF) were given bromocriptine either 1 or 12 hours before anesthesia or received no drug to determine what effect suppression of transient, anesthesia-induced hyperprolactinemia would have on peripheral and follicular fluid hormones, fertilization and cleavage rates, and pregnancy. Thirty minutes after anesthesia, there was a 120-ng/mL rise in serum prolactin (PRL) in control patients versus an insignificant change in women given bromocriptine. Levels of PRL in follicular fluid were significantly less, and estradiol (E2) levels were higher (P less than 0.05) in all bromocriptine-treated patients compared with controls, whereas follicular fluid levels of progesterone (P), inhibin activity, and midluteal serum P were unaffected. Although fertilization and pregnancy rates were similar, a greater proportion of fertilized oocytes from bromocriptine-treated patients advanced to cleaving embryos compared with controls (95% versus 63%, respectively; P less than 0.001). We conclude that bromocriptine, given before anesthesia, can suppress transient, anesthesia-induced hyperprolactinemia and dramatically alter follicular fluid concentrations of PRL and E2. Although these changes in hormonal milieu affected neither oocyte fertilization nor pregnancy rate in our IVF patients, they seemed to have a positive influence on embryonic development after IVF.

Adult↗
PubMed1989

Conservative management of Cushing's syndrome in pregnancy. A case report.

A woman with clinical and laboratory findings of Cushing's syndrome was managed during pregnancy without the use of surgery or drugs to lower her serum cortisol. A good maternal and infant outcome was achieved with conservative measures, and surgical removal of an adrenal adenoma was delayed until the postpartum period.

Adenoma↗
PubMed1989

Transcervical resection of submucous uterine fibroids: an alternative approach to management.

Transcervical resection of submucous uterine fibroids can be an effective alternative to laparotomy and transuterine myomectomy in selected women. To date the authors have performed this procedure in three patients in an ambulatory environment. In two patients, transcervical resection was performed for giant intrauterine myomas which caused pathologic uterine bleeding and infertility. In a third patient the procedure was performed to resect multiple small submucous myomas causing infertility.

Adult↗