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Biomedical subjects

J Owen

Publications and source records attributed to J Owen.

At least 163 records · Page 9Linked to original sources
PubMed1990

Is indicated or spontaneous preterm delivery more advantageous for the fetus?

We performed a case-control study to determine whether fetuses delivered prematurely because of pregnancy complications (primarily pregnancy-associated hypertensive disease) had a different neonatal course than that of those born after either spontaneous preterm labor or after premature rupture of the membranes. Two case-control populations were matched by gestational age at delivery, fetal sex, and race. There was no perinatal survival advantage in babies delivered from "stressed" pregnancies. Selected neonatal morbidities were generally similar, but there was an increased incidence of necrotizing enterocolitis in babies born after preterm labor and a higher incidence of both necrotizing enterocolitis and neonatal sepsis after premature rupture of the membranes. We conclude that a "stressed" pregnancy confers a negligible survival advantage to the fetus.

Adult↗
PubMed1990

Evaluation of a risk scoring system as a predictor of preterm birth in an indigent population.

A risk scoring system designed to predict spontaneous preterm birth was implemented in a large, indigent population as part of a multicenter trial of preterm birth prevention. A total of 7478 women with singleton gestations were screened and followed up prospectively at the Birmingham project center. Patients who had an indicated preterm delivery or a fetal anomaly were excluded from the study population. Analysis by assigned risk score and parity showed that, whereas the sensitivity and positive predictive value were better in multiparous women than in nulliparous women, overall the values were low. Logistic regression analyses of the multiparous and nulliparous populations showed independent sets of significant (p less than or equal to 0.05) risk variables. A history of preterm delivery and a low prepregnancy weight were the most predictive risk factors in the multiparous and nulliparous models, respectively. We conclude that the clinical usefulness of a risk scoring system to predict spontaneous preterm birth in an indigent population is limited.

Age Factors↗
PubMed1990

Topical glyceryltrinitrate causes measurable penile arterial dilation in impotent men.

The current understanding of the intracavernous changes that cause or accompany penile erections has encouraged the use of vasodilators as therapy for erectile dysfunction. An established vasodilator, glyceryltrinitrate, was selected for in vivo study because of its rapid transdermal absorption. Color coded duplex ultrasound was used to assess penile vascular response. In a large group of men with erectile dysfunction significant dilation was noted in response to a small amount of nitroglycerine paste applied to the penis. There is a measurable vasodilatory response that can be induced by synthetic nitrates in penile tissue in impotent men.

Blood Flow Velocity↗
PubMed1990

Magnetic resonance imaging and computed tomography scan for the diagnosis of acute fatty liver of pregnancy.

Magnetic resonance imaging (MRI) and computed tomography were used to diagnose fatty liver of pregnancy in a patient with preeclampsia and thrombotic thrombocytopenia purpura. The clinical course included multiple system failure that necessitated mechanical ventilation, dialysis, and plasmapheresis. The MRI picture is described in this entity for the first time. Both imaging techniques are discussed and compared.

Adult↗
PubMed1990

Thrombin activity induced by balloon angioplasty of the coronary artery in Macaca fascicularis (cynomolgus monkey).

In this paper we address the question of whether balloon angioplasty induces thrombin action. In the studies reported here we measured fibrinopeptide A levels in a group of atherosclerotic monkeys undergoing coronary angioplasty. A blood collection catheter was introduced into the inferior vena cava through a femoral vein, and the angioplasty catheter introduced via the femoral artery. Heparin was administered immediately after insertion of the arterial catheter. Serial blood samples were collected for 20 min before angioplasty and for 10 min after angioplasty. Baseline levels of FpA were high, presumably in response to the trauma of introducing the catheters. After heparin administration the FpA concentration declined with a half-time of 1.1 min. In response to balloon inflation there was a clear increase in the concentration of FpA, despite the presence of a therapeutic concentration of heparin. The magnitude of the FpA rise was markedly different between animals, but was evident in the aggregate data after subtraction of background levels of FpA. By integration of the plasma FpA concentration curve, the amount of fibrinogen converted to fibrin in response to angioplasty was calculated to be approximately 0.4 mg/animal. We conclude that angioplasty induces significant activation of the coagulation system.

Angioplasty, Balloon, Coronary↗
PubMed1990

Nucleotide sequence and evolutionary relationships of cucumber mosaic virus (CMV) strains: CMV RNA 3.

The nucleotide sequence of RNA 3 of two subgroup I strains of cucumber mosaic virus (CMV), Fny-CMV and M-CMV, was determined and compared at both the nucleic acid and protein level with the previously determined, corresponding (partial) sequences of RNA 3 of five other subgroup I strains: C-CMV, D-CMV, I17F-CMV, O-CMV and Y-CMV. Fny-CMV RNA 3 is composed of 2216 nucleotides (nt) and M-CMV RNA 3 2214 nt. Both RNAs contain two open reading frames, the 3a gene and the coat protein gene. These RNAs showed very little nucleotide sequence divergence, either from each other or from the five other subgroup I strains. The nucleotide sequence variation observed was two to 13 differences in the 120 to 123 nt 5' non-translated regions, six to 17 differences in the 840 nt 3a genes, two to 15 differences in the 296 to 299 nt intergenic regions, three to 25 differences in the 657 nt coat protein genes and two to 10 differences in the 299 to 303 nt 3' non-translated regions. Protein sequence similarity was also high, with one to four differences in the 279 amino acids of the 3a proteins and two to 13 differences in the 218 amino acids of the coat proteins. Limited nucleotide sequence variation among nine strains of CMV was also shown using an RNA protection assay and a probe specific for Fny-CMV RNA 3. The limited variation shown by RNA 3 of strains of CMV with different passage histories, isolated in different countries over a 50 year period, suggests that the maintenance of the highly conserved nucleotide sequence may be important for other viral RNA functions or interactions.

Amino Acid Sequence↗
PubMed1989

A comparison of perinatal outcome in patients undergoing contraction stress testing performed by nipple stimulation versus spontaneously occurring contractions.

Perinatal outcomes were analyzed in 848 high-risk pregnancies managed with a prospective weekly contraction stress testing protocol. In 615 patients the last test was performed by a nipple stimulation protocol whereas 233 patients had sufficient spontaneous contractions for performance of the test. All patients were either delivered of their infants or admitted for delivery within 7 days of the last test. The results of the last test were compared to various perinatal outcome parameters. There was no significant difference in perinatal outcomes between the two groups.

Breast↗
PubMed1989

Comparison of predelivery versus postdelivery Kleihauer-Betke stains in cases of fetal death.

A prospective study was undertaken to determine whether the delivery process could introduce a significant amount of fetal cells into the maternal circulation in patients with a fetal death. Sixty-six cases of fetal death were studied over a 39-month period. All patients had both predelivery and postdelivery Kleihauer-Betke stains performed. Of these, three (4.6%) had a massive fetomaternal hemorrhage. None of the postdelivery stains showed evidence of a significant fetomaternal hemorrhage unless results of the antepartum stain had also been positive. We conclude that the delivery process itself does not simulate a massive fetomaternal hemorrhage in cases of fetal death.

Adolescent↗
PubMed1989

Polyarteritis nodosa in pregnancy: a case report and brief literature review.

Patients who develop polyarteritis nodosa in pregnancy generally have a grim prognosis. A young nulliparous woman developed the disease and attained remission before becoming pregnant. Although she developed a recurrence, both mother and infant did well. It appears that if a patient becomes pregnant while in remission the chance of a successful pregnancy outcome is reasonable.

Adult↗
PubMed1989

Free protein S deficiency: a possible association with cerebrovascular occlusion.

A deficiency of free protein S, known to increase the risk of peripheral venous thrombosis, has not been well described in patients with cerebrovascular disease. In a pilot study of 35 patients with symptomatic cerebrovascular disease, using a qualitative crossed immunoelectrophoresis assay we found eight patients with a free protein S deficiency. A Laurell immunoelectrophoresis assay was used to quantify the percentage of free protein S after removal of the inactive protein S C4b-binding protein complex by precipitation with polyethylene glycol 8000. In a quantitative study of 103 patients with cerebrovascular disease, 21 had a free protein S that was less than 20% of the average normal total protein S concentration (normal range 20-40%); 19 had suffered cerebral infarction and the other two had suffered intracranial hemorrhage. The frequency of free protein S deficiency in this group of stroke patients was far higher than the expected prevalence in the general population.

Adolescent↗
PubMed1988

Hemostatic effects of hormonal stimulation in patients with metastatic prostate cancer.

Hemostatic abnormalities are common in patients with metastatic malignancy and are attributed, in part, to materials secreted by tumor cells. Tumor stimulation might therefore cause further perturbation of hemostasis. This article reports observations on the effects of androgen stimulation on multiple hemostatic parameters in patients with metastatic prostate cancer. Testosterone was given before chemotherapy in an experimental protocol designed to increase tumor sensitivity to cytotoxic agents. The following parameters were measured on day 0 (before) and days 2 and 4 of fluoxymesterone administration: PT, APTT, platelet count, plasma betathromboglobulin (BTG), platelet factor 4 (PF4), fibrinogen, fibrin(ogen) split products (FSP), factor VIII coagulant activity (VIII C), von Willebrand factor antigen (vWF Ag), fibrinopeptide A (FPA), antithrombin III (AT III), and protein C antigen (PC). Ten patients were studied during 17 cycles of hormonal stimulation. Baseline levels of BTG, PF4, fibrinogen, FSP, factor VIII C, vWF Ag, and FPA were significantly elevated compared with normal control. Although androgen stimulation resulted in elevation of BTG, FPA, and FSP levels by day 4 in many patients, the changes for the entire group were not statistically significant. Other parameters remained unchanged or were only slightly elevated. Two patients developed laboratory evidence of disseminated intravascular coagulation (DIC) but were clinically unaffected. Our data suggest that most patients with metastatic prostate cancer show evidence of ongoing activation of platelets, coagulation, and fibrinolysis. In a few individual patients, androgen stimulation of this hormonally dependent tumor may cause further activation of platelets, coagulation, and fibrinolysis.

Aged↗
PubMed1988

Complications of long-term anticoagulation.

We used life-table techniques to determine risks of morbidity and mortality associated with long-term warfarin treatment in an anticoagulation clinic. Cumulative risks for life-threatening complications and warfarin-related death among all patients were 1% at 6 months, 5% at 1 year, and 7% at 2 and 3 years. Cox regression analysis using age as a continuous variable failed to show an effect of age on cumulative risks of complication. The occurrence of a minor complication during the course of therapy did not place patients at higher risk for developing a major complication that would prompt discontinuation of therapy or cause death. There was no statistically significant difference between the cumulative risks of patients anticoagulated for cerebrovascular disease and the cumulative risks of patients anticoagulated for other indications.

Adult↗
PubMed1988

Characterization of cucumber mosaic virus. I. Molecular heterogeneity mapping of RNA 3 in eight CMV strains.

RNAs from 13 strains of cucumber mosaic virus (CMV) were divided into two groups on the basis of their ability to hybridize to cDNA of either Fny-CMV RNA or WL-CMV RNA. The extent of the cross-hybridization within one of these groups was analyzed by an RNA protection assay. A cDNA clone of RNA 3 of the Fny strain of CMV was placed in a transcription vector between bacterial promoters T3 and T7. Labeled, minus-sense RNA transcripts prepared from all or part of the cDNA to RNA 3 of Fny-CMV were annealed to the genomic RNA of each of a number of cucumoviruses and digested with RNases. The patterns of RNA fragments protected from digestion were specific for each CMV strain and revealed the extent and location of heterogeneity among the viruses as well as within the Fny-CMV natural population. This approach will allow the differences in host range and disease processes to be correlated with variations in genomic RNAs.

Capsid↗
PubMed1988

Hyperlipidemia and in vivo hemostatic system activation.

Coagulation system activity in vivo is a well-recognized consequence of advanced atherosclerotic disease, the association of coagulation system activity with atherogenesis is much less clear. The data reviewed here argue against ongoing increased coagulation system activity in persons with hyperlipidemia. The possibility remains that episodic activity could easily be missed with available tests, such bursts of activity might well require new agents and strategies for effective control. Failure to find evidence of increased coagulation activity in patients with hyperlipidemia does not refute models of atherogenesis based on thrombosis. Rather, the data reviewed here should cause us to focus attention on the time scale of such events. On the other hand, the findings do allow for a simpler interpretation of data showing evidence of activation of coagulation in patients with concurrent hyperlipidemia.

Arteriosclerosis↗