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Biomedical subjects

S M Cox

Publications and source records attributed to S M Cox.

At least 55 records · Page 3Linked to original sources
PubMed1992

Maternal and perinatal effects of hypertension at term.

This study sought to determine if selected maternal and fetal outcomes in term singleton pregnancies complicated by hypertension during labor differed from those without this complication. All pregnancies delivered at Parkland Memorial Hospital, Dallas, Texas, during 1986 were ascertained using a computerized database. A total of 11,812 term singleton pregnancies ended in delivery during the study period; 1,392 (12%) were complicated by hypertension. Women with a total of 1,383 of these hypertensive pregnancies presented to the hospital with a live fetus. Hypertension was diagnosed in 984 (19%) of the 5,060 primiparous and 399 (6%) of the 6,752 parous women. Hypertension during labor in term singleton pregnancies is associated with increased maternal risks because of the potential complications associated with interventions necessary for successful management. Moreover, hypertension in such pregnancies also increases the perinatal mortality rate. However, this increased rate results from a higher likelihood that fetal death will occur prior to the patient's presentation to the hospital. The risk of fetal morbidity and mortality appears to be low in the hypertensive woman with a term pregnancy admitted to the hospital with a live fetus.

Cesarean Section↗
PubMed1991

A randomized trial of ofloxacin versus cefoxitin and doxycycline in the outpatient treatment of acute salpingitis.

The object of this randomized study was to compare the safety and efficacy of oral ofloxacin, 400 mg twice daily for 10 days, versus intramuscular cefoxitin, 2 gm, plus oral probenecid, 1 gm, followed by oral doxycycline, 100 mg twice daily for 10 days, in the outpatient treatment of uncomplicated acute salpingitis. Thirty-eight women (53%) had Neisseria gonorrhoeae from their pretreatment endocervical or endometrial cultures, and 18 had Chlamydia trachomatis (25%). Thirty-five of 37 women (95%) treated with the ofloxacin regimen were clinically cured, and 34 of 35 (97%) were cured with the cefoxitin-doxycycline regimen (p = 0.52). One clinical failure occurred in each group with N. gonorrhoeae infection, and one failure occurred in the ofloxacin group because of side effects. The bacteriologic response for N. gonorrhoeae in both groups was 100%. The eradication of C. trachomatis was 100% (10/10) for the cefoxitin/doxycycline group and 86% (6/7) for ofloxacin. The side effects were similar in both groups of subjects. In this study both regimens were effective for the outpatient treatment of uncomplicated acute salpingitis.

Acute Disease↗
PubMed1991

Mechanisms of hemolysis and anemia associated with acute antepartum pyelonephritis.

Anemia develops in about a fourth of women whose pregnancy is complicated by pyelonephritis, although its exact mechanism has not been defined clearly. In this study of 18 women with antepartum pyelonephritis, although only a third had anemia (hematocrit less than 30 vol/dl), there was evidence for hemolysis in all 18. Specifically there was a mean decrease in hematocrit of 5 vol/dl from admission to discharge. With scanning electron microscopy, we compared erythrocyte morphologic aberrations that were found in women with renal infection with those of normally pregnant women, and the former had significantly increased proportions of echinocytes in particular, but schistocytes and spherocytes were increased also (total 10.3% vs 1.4%, p less than 0.0001). These changes, especially echinocytosis, have been induced in vitro by lipopolysaccharide, and they are known to lead to premature red blood cell destruction in vivo. We conclude that hemolysis with subsequent anemia in pregnant women with pyelonephritis is caused by lipopolysaccharide-induced red blood cell membrane damage.

Acute Disease↗
PubMed1991

Role of Neisseria gonorrhoeae and Chlamydia trachomatis in intraabdominal abscess formation in the rat.

Our concept of the pathogenesis of acute salpingitis and advanced pelvic infection, such as tuboovarian abscess, is evolving. Although Neisseria gonorrhoeae and Chlamydia trachomatis are thought to play a significant role in acute pelvic inflammatory disease, other microorganisms, such as aerobes and anaerobes, have repeatedly been reported to play a significant role, also, particularly in the patient with advanced disease. A study was designed to evaluate the pathogenesis, and particularly any synergistic role, of some aerobes and anaerobes with N gonorrhoeae and C trachomatis abscess formation. Using the rat model developed by Weinstein and Onderdonk, the study demonstrated that N gonorrhoeae and C trachomatis alone do not produce abscesses. However, when combined with facultative or anaerobic bacteria, synergism with abscess formation is noted frequently. The data support the hypothesis that N gonorrhoeae and C trachomatis initiate infection and that aerobic and anaerobic bacteria act synergistically to produce abscesses. In addition, microorganisms not inoculated were found to be recruited into the infectious process. The organisms may gain access to the peritoneal cavity via the lower genital tract or from transmucosal migration from the intestinal flora.

Abscess↗
PubMed1991

Cerebrovascular accidents complicating pregnancy and the puerperium.

The decreasing incidence of direct causes of maternal death over the past half century has led to a heightened awareness of nonobstetric factors responsible for maternal mortality. For example, cerebrovascular accidents are an important nonobstetric cause of maternal morbidity and mortality. During the 6.5-year period from 1984 to mid-1990, we encountered 15 women in whom pregnancy or the puerperium was complicated by an acute cerebrovascular accident. Six of these women had hemorrhagic strokes and nine had ischemic strokes. During this same time, approximately 90,000 women were delivered at Parkland Memorial Hospital, and thus the incidence of stroke was about one in 6000 pregnancies. Chronic hypertension or preeclampsia was causative in three cases of hemorrhagic stroke. It is important that 20% of the women died as a result of stroke, and of the 12 survivors, 40% have residual neurologic deficits. An aggressive work-up to define the etiology of stroke is necessary in order to implement cause-specific management, with subsequent reduction in morbidity and mortality.

Cerebrovascular Disorders↗
PubMed1990

Randomized investigation of magnesium sulfate for prevention of preterm birth.

One hundred fifty-six women with preterm labor between 24 and 34 weeks' gestation were randomized to receive either intravenous magnesium sulfate or no tocolytic therapy. Magnesuim sulfate infusions of up to 3 gm/hr were used in 76 pregnancies and resulted in a mean serum magnesium concentration of 5.5 +/- 1.4 mEq/L (mean +/- SEM). Compared with 80 control pregnancies, magnesium sulfate tocolysis had no significant effect on duration of gestation, birth weight, neonatal morbidity, and perinatal mortality. We conclude that clinically safe infusions of magnesium sulfate are ineffective when used to prevent preterm birth.

Adult↗
PubMed1990

Chronic renal disease and pregnancy outcome.

During the 18-year period from 1971 through 1988, 37 women whose pregnancies were complicated by moderate or severe renal insufficiency were managed at Parkland Memorial Hospital. Common maternal complications included anemia, chronic hypertension, and preeclampsia. Perinatal complications included midpregnancy losses and low birth weight from preterm delivery, fetal growth retardation, or both. Despite the high incidence of maternal morbidity, 85% of pregnancies in the 26 women with moderate renal insufficiency resulted in a live-born infant; there was one stillbirth and no neonatal deaths. Of the 11 women with severe disease, seven were delivered of live-born infants after greater than or equal to 26 weeks' gestation. Although six of these 37 women had worsening renal function during pregnancy, it seems unlikely that pregnancy per se caused this. More importantly, in four of these six women and in four others who had stable function throughout pregnancy, end-stage renal disease developed within a mean of 4 years after delivery. In 14 women blood volume was determined during pregnancy, and whereas those with moderate disease had normal volume expansion, women with severe disease had significantly attenuated expansion. Finally, serial creatinine clearances did not increase during pregnancy in half the women with moderate insufficiency and none with severe dysfunction.

Anemia↗
PubMed1990

Ticarcillin/clavulanate in the treatment of pelvic infections.

Ticarcillin/clavulanate was used to treat 130 women with pelvic infections. The 129 who completed an initial course of treatment with ticarcillin/clavulanate were analyzed according to type and clinical severity of infection, and pretreatment and posttreatment endometrial bacteriology. There were 26 cases of pelvic inflammatory disease and 103 puerperal infections, 61 of which occurred in women who had delivered by cesarean section (46 elective with no antibiotic prophylaxis at the time of surgery). Of the 129 patients treated, 124 were clinically cured, and one improved (97%). There were four treatment failures, all of which were among a total of 20 cases classified as clinically severe. All the patients designated as treatment failures required prolonged treatment with other antibacterials to achieve a clinical cure, but a longer duration of treatment with ticarcillin/clavulanate might have effected a clinical resolution even in these cases. In vitro examination of endometrial isolates revealed a significant reduction of the minimum inhibitory concentrations (MICs) of beta-lactamase-producing bacteria with the addition of clavulanate to ticarcillin. The relationship of non-beta-lactamase-producing enterococci having relatively high MICs to clinical failure was examined.

Bacteria↗
PubMed1990

The Jarisch-Herxheimer reaction complicating syphilotherapy in pregnancy.

Thirty-three gravidas with syphilis were monitored with hourly vital signs and examinations for 24 hours after treatment with benzathine penicillin G. Fifteen (45%) of the subjects had a Jarisch-Herxheimer reaction, including all three, 12 of 20 (60%), and none of ten of those with primary, secondary, and latent syphilis, respectively. The most common symptoms were fever (73%), uterine contractions (67%), and decreased fetal movement (67%). The signs or symptoms began 2-8 hours after treatment; fevers peaked at 6-12 hours post-therapy and the events usually abated by 16-24 hours after treatment. Uterine contractions and decreased fetal activity began concurrent with maternal fever in eight of ten women reporting contractions. Transient late decelerations were detected in three of 11 monitored patients. Three of the women with Jarisch-Herxheimer reactions delivered infants with congenital syphilis, including one stillbirth, but none of those without a detectable reaction had fetal treatment failures. Prostaglandin F2 alpha and prostacyclin metabolites were elevated transiently in the one subject studied, suggesting their role in mediating the cardiovascular and uterine events in the post-treatment period. The Jarisch-Herxheimer reaction in pregnancy is similar in frequency, character, and intensity to that in nonpregnant adults, but gravidas may have increase uterine activity and transient alterations in fetal well-being. The pregnant patient with a severely affected fetus with congenital syphilis may experience preterm labor, preterm delivery, or fetal death in association with the Jarisch-Herxheimer reaction.

Adult↗
PubMed1989

The importance of the orientation of the C9 substituent to cannabinoid activity.

We have found a correlation between cannabinoid psychopharmacological activity and the orientation of the C9 substituent in one class of cannabinoid derivatives. We report here a study of the active cannabinoids delta 9-tetra-hydrocannabinol (delta 9-THC), delta 8-tetrahydrocannabinol (delta 8-THC), and 11 beta-hexahydrocannabinol (11 beta-HHC); the minimally active cannabinoid 11 alpha-hexahydrocannabinol (11 alpha-HHC); and the inactive cannabinoids delta 7-tetrahydrocannabinol (delta 7-THC) and delta 9,11-tetrahydrocannabinol (delta 9,11-THC). Our working hypothesis is that there are two components of cannabinoid structure which confer upon these compounds reactivity characteristics crucial to activity: the directionality of the lone pairs of electrons of the phenyl group hydroxyl oxygen and the orientation of the carbocyclic ring relative to this oxygen. The structures of these six molecules were optimized by using the method of molecular mechanics as encoded in the MMP2(85) program. Other possible minimum-energy conformations of the carbocyclic ring were calculated by driving one torsion angle in this ring by use of the dihedral driver option in MMP2(85). The rotational energy behavior of the phenyl group hydroxyl in each molecule was studied also by using the dihedral driver option in MMP2(85). We found that the carbocyclic ring in 11 alpha-HHC can exist in either a chair or a twist conformation. The carbocyclic ring in delta 9-THC, in delta 8-THC, and in delta 7-THC was found to exist only in a half-chair conformation, while the carbocyclic ring in 11 beta-HHC and in delta 9,11-THC was found to exist only in a chair form. The results of the rotational energy profiles indicated that the minimum-energy positions of the phenyl group hydroxyls are nearly identical in all molecules. These molecules, then, were found to differ only in the conformation of the carbocyclic ring in each. This conformation, in turn, determines the orientation of this ring and its C9 substituent relative to the oxygen of the phenyl group hydroxyl. In order to assess the orientation of the carbocyclic ring with respect to the phenyl group hydroxyl oxygen in each optimized structure, the following nonbonded torsion angles were measured: C10-C10a-C1-O, C8-C7-C1-O, C11-C9-C1-O, and C9-Q-C1-O (where Q is a dummy atom placed midway between C8 and C10).(ABSTRACT TRUNCATED AT 400 WORDS)

Cannabinoids↗
PubMed1989

Pregnancy complicated by bacterial endocarditis.

In conclusion, bacterial endocarditis is a rare but very serious pregnancy complication that may lead to maternal death. The predisposing factors for the development of endocarditis appeared to have changed during the past two decades. Intravenous drug abuse, rather than rheumatic and congenital heart defects, is emerging as a major cause of endocarditis. Importantly, diagnostic evaluation and therapy during pregnancy are essentially identical to those for nonpregnant patients.

Endocarditis, Bacterial↗
PubMed1989

Cachectin/tumor necrosis factor-alpha formation in human decidua. Potential role of cytokines in infection-induced preterm labor.

This study was conducted as part of an investigation to evaluate the hypothesis that bacterial toxins (LPS or lipoteichoic acid), acting on macrophage-like uterine decidua to cause increased formation of cytokines, may be involved in the pathogenesis of infection-associated preterm labor. We found that cachectin/tumor necrosis factor-alpha (TNF-alpha) was synthesized and secreted into the culture medium by human decidual cells and explants in response to treatment with LPS. LPS treatment also caused an increase in PGF2 alpha production by decidual cells and explants. In amnion cells in monolayer culture, TNF-alpha stimulated PGE2 formation, and TNF-alpha was cytostatic (inhibited [3H]thymidine incorporation into DNA) but not cytolytic in amnion cells. TNF-alpha was not detectable (less than 0.34 ng/ml) in the amniotic fluid of normal pregnancies at midtrimester or at term before or after the onset of labor (n = 44); but TNF-alpha was present at concentrations between 2.8 and 22.3 ng/ml in amniotic fluids of 4 of 20 pregnancies with intact membranes complicated by preterm labor (less than 34 wk gestational age). LPS was present in 10 of the 20 amniotic fluids of preterm labor pregnancies, including all four in which TNF-alpha was present. Bacteria were identified in only one of the four LPS-positive, TNF-alpha-positive fluids. Cytokine formation in macrophage-like decidua may serve a fundamental role in the pathogenesis of preterm labor, including increased prostaglandin formation and premature rupture of the membranes.

Amniotic Fluid↗
PubMed1989

Postpartum endometritis.

Despite the widespread use of prophylactic antibiotics, postpartum endometritis remains a common complication following cesarean section. Metritis is generally polymicrobial and responds to a wide variety of antibiotic regimens. During the past decade, single agents have been shown to be safe and efficacious. The pathogenesis, diagnosis, and treatment options for endometritis are reviewed.

Anti-Bacterial Agents↗
PubMed1989

Acute chorioamnionitis.

In summary, acute intra-amniotic infection or chorioamnionitis is a relatively common complication of pregnancy and may be associated with significant maternal and neonatal morbidity. Maternal mortality is rare, as is mortality in term infants. Mortality in premature infants is probably related to prematurity itself rather than infection per se. Diagnosis is based primarily on the presence of maternal fever. Treatment consists of antibiotics and delivery. Antibiotics should be begun as soon as the diagnosis is made unless delivery is imminent (less than 1 hour). Cesarean section offers no specific advantage to the fetus and may carry increased risk to the mother.

Anti-Bacterial Agents↗
PubMed1988

Low-dose aspirin. I. Effect on angiotensin II pressor responses and blood prostaglandin concentrations in pregnant women sensitive to angiotensin II.

Decreased incidence of proteinuric hypertension after low-dose aspirin therapy is hypothesized to be a consequence of selective thromboxane A2 inhibition and sparing of prostacyclin. This study was designed to ascertain if low-dose aspirin therapy (81 mg/day for 1 week) alters vascular refractoriness to angiotensin II and the prostacyclin/thromboxane A2 ratio in pregnant women sensitive to angiotensin II (n = 17). Low-dose aspirin increased the effective pressor dose of angiotensin II from 5.9 +/- 2.4 to 10.2 +/- 5.5 ng/kg/min (p less than 0.01, mean +/- SD). Platelet-derived serum thromboxane B2 (a metabolite of thromboxane A2), a measure of therapy compliance, decreased from 1804 +/- 1771 to 132 +/- 206 pg/ml (p less than 0.01). Plasma thromboxane B2 decreased from 130 +/- 107 to 19 +/- 12 pg/ml (p less than 0.01). Inhibition was not selective because 6-keto-prostaglandin F1 alpha (a metabolite of prostacyclin) also decreased from 243 +/- 90 to 163 +/- 90 pg/ml (p = 0.039) and prostaglandin E2 was reduced from 155 +/- 67 to 95 +/- 40 pg/ml (p = 0.014). Decreases in thromboxane B2, however, were significantly greater (75% +/- 19%) than decreases in 6-keto-prostaglandin F1 alpha (21% +/- 33%) or prostaglandin E2 (29% +/- 36%); thus the 6-keto-prostaglandin F1 alpha/thromboxane B2 ratio increased from 3.1 +/- 2.0 to 12.4 +/- 9.9 (p less than 0.01). Although low-dose aspirin increases the effective pressor dose of angiotensin II, it does not return to normal pregnancy values. This observation is consistent with the hypothesis that this represents only a partial selective prostaglandin inhibition.

Angiotensin II↗
PubMed1988

Assay of bacterial endotoxin (lipopolysaccharide) in human amniotic fluid: potential usefulness in diagnosis and management of preterm labor.

The long-range goal of our research is to determine whether the presence of bioactive agents of infection in amniotic fluid may serve as sensitive indexes of the existence of infection as the cause of preterm labor in a given pregnancy. The aim of this study was to explore the possibility that bacterial endotoxin (lipopolysaccharide) could be detected and quantified in amniotic fluid. In particular, we sought to ascertain (1) if amniotic fluid could be collected in a manner to prevent endotoxin contamination, (2) whether there were inhibitors of lipopolysaccharide in amniotic fluid, and (3) if Limulus amebocyte lysate-based assays could be used to identify and quantify lipopolysaccharide in this fluid. We found that the Limulus amebocyte lysate assays (gelation assay and chromophore generation assay) were useful in the qualitative and quantitative analysis of lipopolysaccharide in amniotic fluids. Lipopolysaccharide-mediated generation of chromophore in the presence of amniotic fluid was accelerated strikingly compared with that of lipopolysaccharide in endotoxin-free water. In three amniotic fluid samples obtained during preterm labor, lipopolysaccharide was detectable in aliquots of 1 to 10 microliters by use of the gelation assay and lipopolysaccharide was quantifiable by use of chromophore generation assays. Two of these amniotic fluid samples were sterile as determined by bacteriologic examination; in the third sample, Fusobacterium species was identified. We suggest that these assays may be extremely useful in the identification of lipopolysaccharide in amniotic fluid. Indeed, lipopolysaccharide may serve as one marker of infection useful in establishing the cause of preterm labor.

Amniotic Fluid↗