Search PubMed⌕ Search

Biomedical subjects

R N Taylor

Publications and source records attributed to R N Taylor.

At least 109 records · Page 6Linked to original sources
PubMed1988

Mitogenic activity is increased in the sera of preeclamptic women before delivery.

There is increasing evidence that endothelial cell injury and altered endothelial cell function play an important role in the pathogenesis of preeclampsia. Endothelial cell injury can lead to the secretion of potent mitogens by activating platelets and directly through the increased production of peptide growth factors by endothelial cells themselves. This study was undertaken to test the hypotheses that increased secretion of mitogenic factors is a feature of preeclampsia and that this activity could be detected in the serum of preeclamptic women. Paired serum samples were collected in early labor and again at 24 to 48 hours post partum from term patients with preeclampsia (n = 15) and normal pregnant controls (n = 14). A bioassay was used to quantify mitogenic activity in these paired samples by assessing their ability to stimulate the incorporation of tritiated thymidine into deoxyribonucleic acid of confluent, quiescent (GO stage) human fibroblasts in monolayer culture. Mitogenic activity was significantly increased in prepartum, preeclamptic sera compared with normal controls and diminished rapidly postpartum to levels equivalent to normal pre- and postpartum serum. These findings are consistent with endothelial cell injury, a process that we believe plays a central role in the pathophysiology of the preeclamptic syndrome.

Female↗
PubMed1988

Preeclampsia is associated with a serum factor cytotoxic to human endothelial cells.

Preeclampsia occurs in 7% to 10% of pregnancies and is a leading cause of morbidity for mothers and their infants. Intensive investigation has failed to reveal the cause of the multiple organ dysfunction characteristic of this disorder, which abates completely with delivery. However, several observations suggest that endothelial cell dysfunction is a central pathophysiologic event. We report that serum from preeclamptic women is cytotoxic to endothelial cells in vitro. Consistent with the reversal of the clinical condition after delivery, cytotoxic activity in serum of preeclamptic women is reduced after 24 to 48 hours post partum. In contrast, cytotoxic activity of serum from normal pregnant women increases after delivery.

Antibodies↗
PubMed1988

Summary of the Centers for Disease Control human immunodeficiency virus (HIV) performance evaluation surveys for 1985 and 1986.

During 1985 and 1986, the Centers for Disease Control conducted eight surveys to evaluate laboratory performance in testing for antibody to human immunodeficiency virus (HIV). (Other names for this virus include "human T-lymphotropic virus type III" and "lymphadenopathy associated virus.") The first survey was conducted with ten samples and 50 laboratories; the remaining surveys used six samples, but enrollment increased to as many as 475 laboratories. The purpose of these surveys was to measure test performance by the laboratories under the actual conditions of use. The surveys contained duplicate samples to permit measurement of within- and between-survey reproducibility. One survey included positive and negative reference materials as evaluation samples. Results of the Western blot (WB) test were not always positive on samples that were positive by enzyme immunoassay (EIA), and sometimes they were positive on samples that had negative results by EIA. The percentage of positive results reported by laboratories using Electronucleonics tests was lower than that reported by users of Abbott and of Litton tests. positive results on the negative reference material were reported by 13.7% of the Abbott EIA test users. The tests do not seem to be calibrated against an equivalent standard. Within-survey reproducibility was usually above 95% for EIA and WB methods and for the major manufacturers of EIA tests. Between-survey reproducibility was usually above 90%. Reproducibility was below 75% for some combinations of samples, method, and manufacturer. The test performance observed in these surveys may be lower than is actually achieved on patient samples because the samples were selected to measure technical competence and contain a higher frequency of samples with low reactivity than would be encountered with clinical samples. Stratification and weighting of the results in these surveys to estimate performance parameters for a blood bank population indicate that the tests are performing well in this application. If single EIA tests at the performance levels achieved in these surveys were used (no repeat and no confirmation), about 1 sample with positive results in every 50,000 samples tested would be missed and about 2.5% would be false positive results. Because tests are duplicated and confirmed in blood banks, better performance would be expected. Testing for antibody to HIV virus continues to undergo rapid change because of the introduction of new tests, changes in technical aspects of existing tests, and application of testing to changing populations. Such dynamic factors necessitate an ongoing, comprehensive monitoring of test performance.

Antibodies, Viral↗
PubMed1988

Developmental expression of platelet-derived growth factor and its receptor in the human placenta.

To investigate the role of platelet-derived growth factor (PDGF) during human placental development, expression of the genes encoding PDGF, the PDGF-receptor (PDGF-R) and the c-fos protooncogene was measured. Messenger RNAs for these genes were detected throughout pregnancy and peaked coordinately during the second trimester. An identical pattern of PDGF-R protein expression was confirmed by immunoblotting using a specific PDGF-R antiserum, measurement of PDGF-R kinase activity, and [125I]PDGF binding. These findings show that the components of the PDGF pathway are expressed in a concerted fashion throughout human pregnancy and are present at especially high levels during the midtrimester. Our observations suggest that through autocrine and/or paracrine mechanisms, PDGF is likely to play an important role in placental homeostasis.

Female↗
PubMed1988

Pitfall in the diagnosis of ectopic pregnancy: immunocytochemical evaluation in a patient with false-negative serum beta-hCG levels.

Tubal pregnancy specimens from a patient with undetectable serum beta-hCG levels and a control case with a low beta-hCG titer by radioimmunoassay were analyzed using peroxidase-antiperoxidase immunocytochemical localization of placental proteins. The results indicated that deficient production of beta-hCG by ectopic trophoblast was responsible for false-negative pregnancy tests in one patient.

Adult↗
PubMed1987

Abruptio placentae following nipple stimulation.

A case of severe abruptio placentae evolved during the course of prepartum electronic fetal heart rate (FHR) monitoring which was associated with nipple stimulation. The fetal monitor tracing and clinical course are discussed. The unpredictability of abruptio placentae is underscored by the normal appearance of the FHR tracing immediately preceding the event. The association of nipple stimulation with abruptio placentae in this case raises concerns about the potential dangers of this surveillance technique.

Abruptio Placentae↗
PubMed1986

Separation of the pubic symphysis. An underrecognized peripartum complication.

A retrospective review of symphysial separations during pregnancy revealed an incidence of 1:600 deliveries over the previous five years. This figure reflects an occurrence 40-fold or more frequent than the current literature suggests. All the cases in our 11 patients suffering peripartum pubic rupture occurred after spontaneous vaginal deliveries. Maternal age, parity, clinical pelvimetry and fetal weight did not play a clear role in the development of symphysiolysis. Rapid descent of the presenting part in the second stage, however, was a common feature. Nonoperative treatment of pubic diastasis and expectant management of subsequent deliveries seem advisable.

Adult↗
PubMed1985

Correlation in isolated nuclei of template-engaged RNA polymerase II, ovalbumin mRNA synthesis, and estrogen receptor concentrations.

Template-engaged and total RNA polymerase II molecules were quantitated in isolated nuclei at various stages of estrogen withdrawal and secondary stimulation by using [3H]amanitin titration assays. Estrogen receptors, RNA transcriptional activity, and ovalbumin mRNA were also measured, and comparisons were made between these parameters to determine whether any significant correlations exist. In isolated nuclei, the highest positive correlations existed between template-engaged RNA polymerase II, ovalbumin mRNA synthesis in vitro, and estrogen receptor concentration. Interestingly, restimulation of estrogen-withdrawn chicks results in replenishment of RNA polymerase II activity to prewithdrawal levels within 4 h; however, the recovery of the numbers of template-engaged polymerase II molecules, ovalbumin gene transcription, and nuclear receptor binding lags behind. These findings suggest that the estrogen effect on RNA polymerase activity is more rapid than the increase in template-engaged RNA polymerase II and ovalbumin-specific gene transcription. The excellent correlation that exists between nuclear estrogen receptor concentrations, template-engaged RNA polymerase II, and ovalbumin gene transcription strongly supports the hypothesis that estrogen receptors mediate RNA polymerase II binding to sequences associated with preferential transcription of the ovalbumin gene.

Amanitins↗
PubMed1985

Adenocarcinoma of Skene's duct associated with a systemic coagulopathy.

Adenocarcinoma of the urethra is a rare neoplasm which is believed to arise from the periurethral ducts. Four such cases have been diagnosed at our institution during the past 25 years and their clinical courses are summarized in this report. In one patient, a disseminated coagulopathy with a predominantly fibrinolytic component developed. The pathologic mechanism of fibrinolysis is addressed and a successful approach to the medical management of this confusing coagulopathy is outlined.

Adenocarcinoma↗
PubMed1985

Education, training, professional certification, and work patterns of directors in interstate laboratories.

Education, professional training, certification, and work patterns of 988 laboratory directors employed in 440 clinical laboratories licensed under the Clinical Laboratories Improvement Act of 1967 are examined. Directors of hospital laboratories as opposed to independent laboratories were more likely to be physicians (82.8% vs. 68.0%), to have completed a formal residency program (75.5% vs. 62.0%), and to be certified in both anatomic and clinical pathology (65.3% vs. 57.1%). Only 51.9% of pathologists confined their work to a single laboratory, while 64.8% of directors with Ph.D.s or other doctorates directed only one laboratory. Most laboratories (81.5%) have at least one associate director. Hospital directors are more often full time (30 or more hours per week) than their independent laboratory counterparts, 74.4% vs. 42.4%, respectively. When the education and experience of individuals entering the field between the 1950s and 1970s are examined, it is evident that fewer individuals with bachelor's or master's degrees now are able to qualify as laboratory directors.

Certification↗
PubMed1985

Malignant fibrous histiocytoma of the vulva.

Primary sarcomas of the vulva are rare neoplasms; malignant fibrous histiocytoma is a sarcoma that usually occurs in the extremities of elderly patients, but it also has been seen in a number of other sites. Presented is the second case report of malignant fibrous histiocytoma arising in the vulva. The diagnosis and management of vulvar sarcomas are reviewed.

Adult↗
PubMed1985

Diagnosis of breast masses in pregnant and lactating women by aspiration cytology.

Five pregnant women with dominant breast masses underwent fine-needle aspiration cytology. Fine-needle aspiration cytology findings of the three patients with benign pregnancy adenomas and the two patients with ductal carcinoma are described. More extensive use of fine-needle aspiration cytology in the evaluation of breast masses in pregnant patients may decrease delays in diagnosis of breast cancer in pregnant women.

Adenoma↗
PubMed1984

Heterotopic skin in the uterus. A report of an unusual case.

A case occurred of heterotopic skin in the uterus, with hair protruding from the cervix. The patient was on immunosuppressive therapy and 30 months earlier had undergone pregnancy termination at 14 weeks. Microscopic examination revealed a single endometrial polyp composed of mature squamous epithelium, adnexal structures and terminal hairs. Previous reports have been published on heterotopic tissue of all types in the uterus, and three hypotheses about their origin have been offered.

Adult↗
PubMed1983

Results of the Centers for Disease Control experimental proficiency testing survey for serum alpha-fetoprotein.

An experimental proficiency testing survey for serum alpha-fetoprotein was conducted among 16 cooperating laboratories. Samples of placental cord serum serially diluted in normal adult serum (simulated maternal serum) were assayed. Results were analyzed for qualitative and quantitative relative accuracy, precision on duplicate and nonduplicate (dilution-related) samples, parallelism, and comparability of units. Although some results had wide distribution, relative accuracy improved when results were normalized against a standard. This procedure improved the overall geometric standard deviation among laboratories on quantitative results from 1.300 to 1.088 and compressed the limits for consensus ranges of results to 40% of that of the unnormalized data. No significant differences in actual mean values were noted between international units per milliliter and nanograms per milliliter in measuring alpha-fetoprotein concentrations at the precision obtained in this study. In interpreting whether a sample was "low or normal" or "abnormally high" for alpha-fetoprotein, we observed that an 80% or greater consensus was achieved on only 6 of the 10 survey samples because borderline samples were included in the survey.

Centers for Disease Control and Prevention, U.S.↗