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Biomedical subjects

J Owen

Publications and source records attributed to J Owen.

At least 145 records · Page 8Linked to original sources
PubMed1991

In vivo insulin action in hepatocellular and cholestatic liver cirrhosis.

The in vivo dose response curve to insulin were studied, using an euglycemic insulin clamp technique, in 13 cirrhotic patients [8 with "hepatocellular" (HC) (nonalcoholics) and 5 with "cholestatic" (CHOL) cirrhosis] and 12 healthy controls (N). Subjects were studied in the basal state and during infusion of insulin at 3 different rates - 1, 3, 10 mU kg-1 min-1. Insulin responsiveness was similar in N and in HC, but it was 23% greater in CHOL (p less than 0.001). Insulin sensitivity was decreased in cirrhotics as compared with N but this difference was only significant (p less than 0.001) in HC. (ED50:62 + 5, 88 + 13 and 136 + 16 muu ml-1 in N, CHOL and HC respectively). Insulin clearance rate (ICR) was significantly (p less than 0.005) decreased in HC (1060 +/- 80, 996 +/- 95 and 776 +/- 128 ml sq m-1 ml-1 in N, CHOL and HC respectively. Basal hepatic glucose production (BHGP) was 39% lower in HC (p less than 0.005) and 24% lower in CHOL (p less than 0.05) than in N. Erythrocyte cholesterol phospholipid ratio was significantly elevated (p less than 0.001) in both groups of cirrhotic patients but was not correlated to specific metabolic changes described. In summary: i) intervariations in insulin dependent glucose metabolism were described in different cirrhotic groups; ii) basal hepatic glucose production and insulin clearance rate impaired in the different groups of cirrhotics; iii) the role of decreased cholesterol/phospholipid ratio on tissues glucose metabolism in cirrhotic patients should be further studied.

Adult↗
PubMed1991

A randomized, double-blind trial of prostaglandin E2 gel for cervical ripening and meta-analysis.

The ability of prostaglandin E2 to prepare the unripe cervix before an indicated labor induction is controversial. We therefore tested 100 pregnant women in a randomized, double-blind trial with intracervical prostaglandin E2 gel, 0.5 mg. The 53 women who received the placebo gel had an outcome similar to that of the 47 women who received the prostaglandin E2 gel. The mean change in cervical score, mean application-to-delivery interval, incidence of uncomplicated spontaneous labor, incidence of cesarean delivery for a failed induction, and the overall cesarean section rate were not significantly different for the two groups. A meta-analysis, incorporating 18 studies of 1811 patients who received a single application of at least 5 mg prostaglandin E2 gel intravaginally or 0.5 mg intracervically, demonstrated no significant decrease in the overall cesarean delivery rate (p = 0.85). We conclude that the use of single-dose intracervical prostaglandin E2 gel for cervical ripening has little effect on labor induction. Moreover, the use of single-dose intracervical or intravaginal prostaglandin E2 gel does not alter the incidence of cesarean delivery, even when large numbers of patients are analyzed by combining the results of similar reports.

Adult↗
PubMed1991

Oligohydramnios: antepartum fetal urine production and intrapartum fetal distress.

Animal and human studies suggest that fetal oliguria is a normal physiologic response to hypoxemia. To assess the clinical significance of this observation, we studied (before their admission) 51 fetuses of women whose pregnancies were complicated by oligohydramnios at greater than or equal to 38 weeks' gestation. We found that the mean hourly fetal urine production decreased significantly in relation to the severity of subsequent intrapartum fetal compromise. The mean antepartum rate was 95 ml/hr in the 21 fetuses with a normal intrapartum heart rate pattern; this fell to 59 ml/hr in the 18 fetuses who had an abnormal intrapartum heart rate pattern but who responded to intrauterine resuscitation. The rate was 33 ml/hr in the 12 fetuses who were delivered by cesarean section as a result of fetal distress. These findings suggest that oligohydramnios associated with fetal oliguria may be used to identify those fetuses who have less intrinsic or uteroplacental reserve than do those of women with oligohydramnios who have a higher rate of fetal urine production.

Adult↗
PubMed1991

Effects of compression and devascularisation on ulnar nerve function. A quantitative study of regional blood flow and nerve conduction in monkeys.

This study investigated the effects of compression, devascularisation and ischaemia with compression on blood flow and function of the ulnar nerve in monkeys. The hydrogen washout technique assessed blood flow; nerve conduction tests determined nerve function. 100 g of external compression produced a significant but incomplete reduction of intraneural blood flow, when conduction velocity decreased significantly and response amplitude deteriorated to zero 28 minutes after the onset of compression. Short-segment devascularisation stopped blood flow but did not influence response latency or velocity. Amplitude was diminished significantly 44 minutes after devascularisation. Tourniquet ischaemia followed by compression produced temporary variability in latency and velocity, while amplitude was diminished only during the compression phase following ischaemia. The overall results suggested that compression and ischaemia influence the nerve conduction response differently and that the effects of compression are potentiated by previous ischaemia, even if this was of short duration.

Animals↗
PubMed1991

Neonatal complications at term as related to the degree of umbilical artery acidemia.

The degree of umbilical arterial acidemia associated with immediate newborn morbidity has not been determined. Therefore we compared 358 term infants with umbilical artery acidemia (pH less than 7.20) with 358 term, nonacidotic matched control infants, to evaluate immediate neonatal complications in both groups. Nonacidotic was defined as an umbilical artery pH greater than or equal to 7.20. Complications included seizures, persistent hypotonia, and/or signs of end-organ damage such as renal or cardiac dysfunction. None of the 693 newborns with an umbilical artery pH greater than or equal to 7.00 had such complications. Two of 23 infants with an umbilical artery pH less than 7.00 had sequelae related to intrapartum asphyxia. In these two infants the umbilical artery pH was less than 7.00, the 1-minute and 5-minute Apgar scores were less than or equal to 3 and the acidemia was metabolic in nature.

Acidosis↗
PubMed1991

Protein S deficiency and bilateral branch retinal artery occlusion.

A macular branch retinal artery occlusion developed in the right eye of a 25-year-old woman when she was 38 weeks pregnant. She subsequently presented 5 days postpartum with a branch retinal artery occlusion in her left eye. Although her initial work-up did not reveal a source for her occlusions, subsequent studies have documented a deficiency of protein S.

Adult↗
PubMed1991

Mid-second-trimester labor induction: concentrated oxytocin compared with prostaglandin E2 vaginal suppositories.

A concentrated oxytocin infusion and prostaglandin E2 (PGE2) vaginal suppositories were compared in a retrospective analysis for indicated abortion in the mid-second trimester (17-24 weeks' gestation). Eighty-one women underwent second-trimester pregnancy termination, 59 by PGE2 suppositories and 22 by concentrated oxytocin infusion. Success was achieved by PGE2 in 93% (55 of 59) and oxytocin in 91% (20 of 22). The mean duration of labor was 13.1 hours with PGE2 and 8.2 hours with oxytocin. The mean dose of PGE2 was 65.2 mg; of oxytocin, 200 units. Women who received PGE2 experienced nausea (46%), vomiting (37%), fever (64%), and diarrhea (20%) despite appropriate premedication. Few side effects occurred in the women who were treated with oxytocin. We conclude that concentrated oxytocin infusion seems to be a reasonable alternative to PGE2 vaginal suppositories for induction of labor in the mid-second trimester.

Abortion, Induced↗
PubMed1991

Rapid localization of indium-111-labeled inhibited recombinant tissue plasminogen activator in a rabbit thrombosis model.

The thrombus localizing properties of indium-111-recombinant tissue plasminogen activator (111In-rt-PA) have been investigated in an effort to achieve prompt and accurate detection of thrombi. Unlike previous studies with rt-PA, the active plasminogen catalytic site was permanently inhibited with peptides of chloromethyl ketone so that the radiotracer binds to fibrin without causing fibrinolysis. Thrombi were created in the external jugular vein of 14 male New Zealand white rabbits followed by injection of 111In-rt-PA. The agent cleared rapidly in vivo with a half-time of 4.6 min. The thrombus: blood ratio in nonheparinized rabbits (n = 7) was 6.39 +/- 0.86. The ratio in heparinized rabbits (n = 4) was 3.11 +/- 0.23. Thrombi were clearly visible in the planar images of both groups 1 hr postinjection. The combination of rapid thrombus localization and positive images, especially in the presence of anticoagulation, suggests that further work is warranted with rt-PA thrombus imaging.

Amino Acid Chloromethyl Ketones↗
PubMed1990

The virB operon of Agrobacterium tumefaciens pTiC58 encodes 11 open reading frames.

Agrobacterium tumefaciens genetically transforms plant cells by transferring a copy of its T-DNA to the plant where it is integrated and stably maintained. In the presence of wounded plant cells this process is activated and mediated by the products of the vir genes which are grouped into six distinct loci. The largest is the virB locus spanning 9.5 kb. Transposon mutagenesis studies have shown that virB gene products are required for virulence but their functions remain largely unknown. To provide information relevant to understanding the function of VirB polypeptides, the nucleotide sequence of the virB operon from a nopaline plasmid, pTiC58, is presented here. Eleven open reading frames (ORFs) are predicted from this sequence. The predicted sizes of 10 of the 11 VirB polypeptides are verified by specific expression in Escherichia coli. Only the product of the smallest ORF potentially encoding a 5.8 kDa polypeptide has not been detected. The initiation of translation of five virB ORFs occurs at codons that overlap the termination codons of the ORF immediately upstream; thus, translational coupling may be an important mechanism for efficient translation of the large virB polycistronic mRNA. Based on hydropathy plot analysis nine of the virB ORFs encode proteins that may interact with membranes; these data support the earlier hypothesis that virB gene products may form a membrane pore or channel to mediate exit of the T-DNA copy (T-strands) from Agrobacterium into the plant cell. A comparison of the two published octopine virB sequences with the nopaline sequence presented here is made.

Amino Acid Sequence↗
PubMed1990

Fatal or severely disabling cerebral infarction during hospitalization for stroke or transient ischemic attack.

Six (1%) of 578 patients admitted for cerebral infarction or transient ischemic attack (TIA) suffered a fatal or severely disabling in-hospital cerebral infarction following a period of stabilization or improvement lasting more than 1 day. These infarctions were characterized by the sudden onset of stupor or coma and subsequent development of transtentorial herniation due to carotid or middle cerebral artery territory infarction, or widespread brain-stem infarction due to basilar occlusion. Only one patient survived. Four patients had large-vessel disease documented by Doppler, angiography, or at autopsy. Each of these six infarcts occurred during the morning hours, 4-9 days after the initial event, 3-8 days after initiation of intravenous heparin, and within 4-8 h after intravenous heparin had been discontinued. No coagulation abnormalities were documented. We believe that these cases indicate that among patients admitted for cerebral infarction or TIA, fatal or severely disabling in-hospital cerebral infarction after a period of stabilization or improvement may occur in patients having an initially mild to moderate clinical deficit, that those suffering large artery disease may be at greater risk, and that there may be a relationship between heparin withdrawal and cerebral infarction in some patients.

Cerebral Infarction↗
PubMed1990

A prospective randomized study of saline solution amnioinfusion.

We performed a prospective randomized study of saline solution amnioinfusion in four types of pregnancy complications: postterm pregnancy, variable decelerations in labor, preterm labor, and oligohydramnios-suspected growth retardation. A total of 100 patients were randomized, 43 to undergo amnioinfusion and 57 to be in a control group. Patients undergoing amnioinfusion had a significantly decreased incidence of postpartum endometritis (2.4% vs 19%, p = 0.01) and a lower incidence of cesarean delivery that was due to fetal distress in labor (4.7% vs 16%, p = 0.07). The use of amnioinfusion also made a significant contribution to the four-quadrant ultrasonographic estimate of amniotic fluid volume (14.7 vs 9.8 cm, p less than 0.001). All other maternal and neonatal outcome parameters were similar between the two groups. We conclude that saline solution amnioinfusion in labor may be a beneficial procedure but that further studies are needed.

Adolescent↗
PubMed1990

Magnesium tocolysis: serum levels versus success.

The relationship between maternal serum magnesium levels and tocolytic success is poorly established. We performed a retrospective analysis of 101 episodes of preterm labor treated with magnesium sulfate and compared the initial, average, and maximum serum magnesium levels with tocolytic success at 48 hours and 7 days. There was no difference in the proportions of tocolytic success when serum levels were less than 6 mg/dl compared with levels of greater than or equal to 6 mg/dl. Similar analyses on either side of 5 mg/dl also revealed no significant relationship. Mean serum magnesium levels in patients with successful tocolysis were statistically similar to those of patients in whom tocolysis failed. Multiple logistic regression analysis also failed to establish a positive relationship between serum magnesium levels and tocolytic success. We conclude that serum magnesium levels alone should not serve as an end point of therapy.

Adult↗