Incarceration histories of homeless veterans and progression through a national supported housing program

There is increasing concern that adults with a past history of incarceration are at particular disadvantage in exiting homelessness. Supported housing with case management has emerged as the leading service model for assisting homeless adults; however there has been limited examination of the success of adults with past history of incarceration in obtaining housing within this paradigm. Data were examined on 14,557 veterans who entered a national supported housing program for homeless veterans, the Housing and Urban Development-Veterans Affairs Supportive Housing program (HUD-VASH) during 2008 and 2009, to identify characteristics associated with a history of incarceration and to evaluate whether those with a history of incarceration are less likely to obtain housing and/or more likely to experience delays in the housing attainment process. Veterans who reported no past incarceration were compared with veterans with short incarceration histories (≤ 1 year) and those with long incarceration histories (>1 year). A majority of participants reported history of incarceration; 43 % reported short incarceration histories and 22 % reported long incarceration histories. After adjusting for baseline characteristics and site, history of incarceration did not appear to impede therapeutic alliance, progression through the housing process or obtaining housing. Within a national supported housing program, veterans with a history of incarceration were just as successful at obtaining housing in similar time frames when compared to veterans without any past incarceration. Supported housing programs, like HUD-VASH, appear to be able to overcome impediments faced by formerly incarcerated homeless veterans and therefore should be considered a a good model for housing assistance programs.

Pathophysiology and medical management of systemic hypertension and pre-eclampsia in pregnancy

Hypertension in pregnancy includes a group of distinct disorders that require special consideration in both prevention and pharmacological treatment. In recent years, there have been few advances regarding the pathophysiology and prevention of pre-eclampsia, however there have been some promising studies regarding possible modes of screening women for preeclampsia before clinical signs and symptoms are apparent. The recommendations for first-line drug therapy for the hypertensive complications of pre-eclampsia, and the recommendations for pharmacological treatment of women with chronic hypertension antedating pregnancy, have changed little primarily because first-line medications have the advantage of having had more extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for the hypertensive disorders of pregnancy; whether these therapies can eventually replace the standard recommended medications will require more extensive long-term investigation.

Reference values of amniotic fluid neuron-specific enolase

OBJECTIVE

Enolase is a dimeric cytoplasmic enzyme whose double gamma isoenzyme, neuron-specific enolase, is predominantly found in neuronal and neuroendocrine tissues. Cell injury causes its release into the blood and cerebrospinal fluid (CSF). Neuron-specific enolase has been measured in the serum and CSF of adults and full-term asphyxiated neonates as a marker of neurological injury. We recently observed an elevation of neuron-specific enolase in the amniotic fluid of women whose neonates subsequently developed intraventricular hemorrhage or periventricular leukomalacia. The purpose of our study was to establish reference values of neuron-specific enolase in the amniotic fluid as a function of gestational age.

METHODS

A total of 110 amniotic fluid samples, obtained primarily for genetic studies (16-20 weeks, n = 22), for evaluation of preterm labor (21-35 weeks, n = 66) and for fetal lung maturity studies (36-40 weeks, n = 22), were analyzed for neuron-specific enolase. Samples were from women who subsequently delivered term neonates with normal neurological examinations or who delivered preterm neonates with normal neurosonograms up to the 7th day of life. Descriptive statistics and non-parametric correlations were used for analysis.

RESULTS

There was no correlation between gestational age and concentration of neuron-specific enolase (Spearman's r = 0.059, p = 0.63). The overall mean neuron-specific enolase value was 2.5 +/- 1.39 microg/l. The highest value obtained was 6 microgl. Of the 110 women, 105 (95.5%) had neuron-specific enolase values of less than 5 microg/l, while five (4.5%) had values ranging from 5 to 6 microg/l.

CONCLUSIONS

The amniotic fluid level of neuron-specific enolase does not change as a function of gestational age. These stable levels may have utility in the evaluation of cases with fetal neurological injury.

Sonographically estimated fetal weight percentile as a predictor of preterm delivery

OBJECTIVE

To evaluate the association between relative growth restriction and preterm birth.

STUDY METHODS

Pregnant women referred for sonographic fetal weight assessments between 24 and 34 weeks of gestation were studied for gestational age at delivery. If a patient underwent more than one study, only the last one was considered. Patients with delivery induced iatrogenically or with abnormal growth patterns due to known pathology, such as maternal diabetes or fetal congenital anomaly, were excluded. A gestational age of 37 weeks or less was considered preterm and a gestational age of more than 37 weeks at delivery was considered term. Fetal weight estimation was obtained by Hadlock's formula based on biparietal diameter, femur length, and head and abdominal circumferences. The estimated fetal weight percentile was computed according to William's tables. Mean gestational age and incidence of preterm delivery for each fetal weight percentile between 1 and 100, at increments of 10, were calculated. The mean estimated fetal weight percentile, biparietal diameter, femur length, head circumferences and abdominal circumferences of preterm and term patients were compared.

RESULTS

Among the 419 patients who met the inclusion criteria, duration of gestation was significantly shorter in fetuses with low estimated fetal weight percentile. The risk of preterm birth was 49% in fetuses of less than the 40th birth-weight percentile compared with a risk of 20% in fetuses of more than the 40th birth-weight percentile, representing a relative risk of 2.3. Individual fetal measurements indicate a head-sparing effect in the preterm group.

CONCLUSION

Sonographically estimated fetal weight percentile measured between 24 and 34 weeks' gestation may be used as an additional and individually pertinent predictor of preterm birth.

Antenatal steroids and neonatal periventricular leukomalacia

OBJECTIVE

To evaluate the effect of antenatal steroid treatment on the development of neonatal periventricular leukomalacia.

METHODS

This retrospective cohort study included 1161 neonates with gestational ages of 24-34 weeks and birth weights of 500-1750 g, divided into two groups on the basis of antenatal steroid treatment. Neonatal neurosonograms were done on days 3 and 7 of life and labeled normal or abnormal. The abnormal outcomes evaluated were periventricular leukomalacia or intraventricular hemorrhage, periventricular leukomalacia with intraventricular hemorrhage, and isolated periventricular leukomalacia. The group treated with antenatal steroids was compared with the untreated group for these outcomes.

RESULTS

Antenatal steroids were associated with significantly less periventricular leukomalacia or intraventricular hemorrhage (23% versus 31%, P =.005), periventricular leukomalacia with intraventricular hemorrhage (5% versus 11%, P =.001), and isolated periventricular leukomalacia (3% versus 7%, P =.009). Logistic regression analysis of antenatal steroid treatment, controlling for confounding maternal and neonatal characteristics, indicated that neonates treated with antenatal steroids had a 56% lower likelihood of periventricular leukomalacia with intraventricular hemorrhage (adjusted odds ratio [OR] 0.44, 95% confidence interval [CI] 0.25, 0.77) and a 58% lower likelihood of isolated periventricular leukomalacia (adjusted OR 0.42, 95% CI 0.20, 0.88).

CONCLUSION

Antenatal steroid treatment was associated with over 50% reduction in the incidence of periventricular leukomalacia in preterm neonates. Increased use of antenatal steroid therapy might improve long-term neonatal neurologic outcomes.

Histologic chorioamnionitis, antenatal steroids, and perinatal outcomes

OBJECTIVE

To determine the perinatal effects of histologic chorioamnionitis on preterm neonates and the effectiveness of antenatal steroids in the presence of histologic chorioamnionitis.

METHODS

We studied neonates at our institution who weighed 1750 g or less at birth from January 1990 through December 1997. The population was stratified primarily by presence of histologic chorioamnionitis and secondarily by exposure to antenatal steroids. Subgroups were compared by various perinatal outcomes and confounding variables. Student t test, chi(2), Fisher exact test, and logistic regression were used for analysis.

RESULTS

Among 1260 neonates entered, the placentas of 527 had evidence of histologic chorioamnionitis and 733 did not. Those with histologic chorioamnionitis had a lower mean gestational age, lower birth weight, and higher rate of major neonatal morbidities than those without it. After adjusting for confounding variables, histologic chorioamnionitis independently associated with lower gestational age, lower birth weight, and neonatal death. Among neonates exposed to antenatal steroids who had histologic chorioamnionitis, there was a significantly lower incidence of low Apgar scores (18% compared with 33.5%, P <.001), respiratory distress syndrome (RDS) (39.6% compared with 55.9%, P <.001), intraventricular hemorrhage and periventricular leukomalacia (21.9% compared with 36.9%, P <.001), major brain lesions (7.7% compared with 18.4%, P <.001), patent ductus arteriosus (14.8% compared with 23.7%, P =.018), and neonatal death (8.3% compared with 16.2%, P =.02), with no increase in rate of proven neonatal sepsis (18.3% compared with 14%, P =.24).

CONCLUSION

Histologic chorioamnionitis increases major perinatal morbidity through its association with preterm birth and is independently associated with neonatal death. In the presence of histologic chorioamnionitis, antenatal steroids significantly decreased the incidence of RDS, intraventricular hemorrhage and periventricular leukomalacia, major brain lesions, and neonatal mortality, without increasing neonatal sepsis.

Placenta accreta and methotrexate therapy: three case reports

Placenta accreta is a complication that is rising in incidence. The reported experience of methotrexate treatment in the conservative management of placenta accreta is scant. Three cases of placenta accreta managed with methotrexate are presented. Case 1: A woman had an antenatal diagnosis of placenta percreta. A successful manual placental removal occurred on post-cesarean day 16. Case 2: A woman had retention of a placenta accreta after a term vaginal delivery. Successful dilation and curettage were performed on postpartum day 37. Case 3: A woman had an antenatal diagnosis of placenta previa-percreta with bladder invasion. A simple hysterectomy was performed on post-cesarean day 46. Conservative management and methotrexate treatment resulted in uterine preservation in two of our three patients; however, this treatment did not prevent significant delayed hemorrhage. In view of the rapid resolution of vascular invasion of the bladder, methotrexate may have an important role in the management of placenta percreta with bladder invasion. The utility of methotrexate treatment with the conservative management of placenta accreta requires further evaluation.

Amniocentesis for selection before rescue cerclage

OBJECTIVE

To determine whether diagnostic amniocentesis should be part of evaluations of women under consideration for rescue cerclage.

METHODS

We reviewed the obstetric records of 25 candidates for rescue cerclage seen between June 30, 1995, and July 1, 1997. Rescue cerclage was defined as a procedure on a cervix with an internal os dilated at least 2 cm and 50% effaced, with membranes visible at the external os. Transabdominal amniocentesis was offered as part of the preoperative evaluation, and amniotic fluid (AF) was sent for glucose and lactate dehydrogenase level determinations, Gram staining, and culture for aerobic and anaerobic bacteria. Placentas were examined for histopathologic evidence of inflammation. The women were divided into three groups. Eleven women had rescue cerclage after amniocentesis, seven had rescue cerclage after declining amniocentesis, and seven had amniocentesis but were treated conservatively because of AF markers of infection. Analysis of variance and chi(2) statistics were used.

RESULTS

The group that had rescue cerclage after amniocentesis had a significantly longer mean admission-to-delivery interval, higher mean gestational age at delivery, higher mean birth weight, and higher neonatal survival rate than did the group that had rescue cerclage without amniocentesis and the group that had no cerclage after amniocentesis (P <.001).

CONCLUSION

Amniocentesis before rescue cerclage placement identified women with subclinical chorioamnionitis who would not benefit from cerclage.

Alterations in relaxation to lactate and H(2)O(2) in human placental vessels from gestational diabetic pregnancies

We determined whether alterations in the mechanism of relaxation to H(2)O(2) potentially contribute to the enhanced prostaglandin-mediated contractile response to H(2)O(2) and posthypoxic reoxygenation seen in human placental vessels of pregnancies with gestational diabetes mellitus (GDM). Isolated placental arteries and veins from GDM and uncomplicated full-term pregnancies were precontracted with prostaglandin F(2alpha) (PO(2) 35-38 Torr) and then exposed to lactate (1-10 mM), arachidonic acid (0.01-10 microM), nitroglycerin (1 nM-1 microM), forskolin (0.01-10 microM), or H(2)O(2) (1 microM-1 mM + 10 microM indomethacin). The rates of tissue H(2)O(2) metabolism by catalase and nitrite production were measured. The relaxation to lactate was reduced in GDM placental arteries and veins by 54-85 and 66-80%, and the relaxation to H(2)O(2) was inhibited by 80-94% in GDM placental veins compared with vessels from uncomplicated full-term pregnancies. H(2)O(2) caused only minimal relaxation of placental arteries. Responses to other relaxing agents were not altered in the GDM placental vessels. Diabetic vessels showed rates of nitrite production that were increased by 113-195% and rates of H(2)O(2) metabolism by catalase that were decreased by 44-61%. The loss of relaxation to H(2)O(2) and lactate (mediated via H(2)O(2)), perhaps as a result of the inhibition of catalase by nitric oxide, may explain the previously reported enhancement of prostaglandin-mediated contractile responses to H(2)O(2) and posthypoxic reoxygenation seen in GDM placental vessels.

Pharmacologic approaches for the management of systemic hypertension in pregnancy

Hypertension in pregnancy includes a group of distinct disorders that require special consideration in both prevention and pharmacologic treatment. In recent years, there have been few advances regarding the pathophysiology and prevention of preeclampsia, or in recommendations for first-line drug therapy of the hypertensive complications of preeclampsia. Similarly, the recommendations for pharmacologic treatment of women with chronic hypertension antedating pregnancy have changed little, primarily because first-line medications have the advantage of having been the subjects of extensive research experience. Recent clinical trials have demonstrated the efficacy and safety of various second-line drugs for treating hypertensive disorders of pregnancy; whether these therapies can eventually replace the standard recommended medications will require more extensive long-term investigation.

Reduced risk of low weight births among indigent women receiving care from nurse-midwives

STUDY OBJECTIVE

To examine the effect of a comprehensive prenatal and delivery programme administered by nurse-midwives on the risk of low weight births among indigent women.

STUDY DESIGN

Historical prospective study. Birth outcomes among the cohort were compared with all county births during the same period, adjusting for maternal age and race. Results are expressed as relative risks with 95% confidence intervals.

SETTING

An enhanced Medicaid funded pre-natal programme administered by nurse-midwives from 1992 to 1994 in Westchester County, New York.

PARTICIPANTS

Indigent mothers (n = 1443), between the ages of 15 and 44, who were residents of Westchester County and indicated having Medicaid or no health care coverage.

RESULTS

There were 1474 live births among cohort mothers. Mean (SD) gestational age was 39.4 (1.9) weeks. Less than 6% of births occurred before 37 weeks gestation. The mean birth weight of cohort infants was 3365.6 (518.6) g. Only 4.1% of the cohort births were less than 2500 g. Compared with all county births, the cohort showed a 41% reduction in the risk of low weight births (RRlbw = 0.59, 95% CI: 0.46 to 0.73, p < .001) and a 56% reduction when compared with county Medicaid births only (RR = 0.44, 95% CI: 0.34 to 0.57, p < .005) adjusting for maternal age and race. Larger reductions were found for very low weight births.

CONCLUSIONS

Mothers need not be considered at high risk for adverse pregnancy outcomes based on their socioeconomic status alone. Moreover, a comprehensive prenatal programme administered by nurse-midwives may promote a reduction in adverse pregnancy outcomes among indigent mothers.

Effectiveness of multidose antenatal steroids

OBJECTIVE

To compare effectiveness between single and multiple courses of antenatal steroids in preterm births and determine adverse effects attributable to multiple courses.

METHODS

We studied retrospectively the neonatal outcomes of infants who weighed 1750 g or less at birth between January 1990 and December 1997. Infants exposed to a single course were compared with those exposed to two or more courses of antenatal steroids, with respect to various perinatal outcome variables.

RESULTS

Ninety-three neonates were exposed to two or more courses of antenatal steroids and 261 neonates had been given single courses. The mean (+/- standard deviation) gestational age (29.6 +/- 2.8 weeks compared with 28.7 +/- 2.7 weeks; P = .007) and birth weight (1252 +/- 321 g compared with 1159 +/- 339 g; P = .013) were significantly higher among neonates exposed to multiple courses. There were no significant differences between groups in perinatal outcomes; however, those exposed to multiple courses had a significantly lower rate of respiratory distress syndrome (RDS) (17 [18%] compared with 107 [41%]; P < or = .001) and surfactant use (40 [43%] compared with 149 [57%]; P = .02). Adjusting for confounding variables, multiple courses of steroids were significantly associated with a 65% reduction in the incidence of RDS (odds ratio 0.35; 95% confidence interval = 0.18, 0.70; P = .003).

CONCLUSION

Compared with single courses, multiple courses of antenatal steroids reduced significantly the incidence of RDS with no apparent increase in neonatal sepsis or disturbances in fetal growth.

Effect of causing fetal cardiac asystole on second-trimester abortion

OBJECTIVE

To compare second-trimester abortions with prostaglandin (PG) E2, with and without pretreatment-induced fetal death.

METHODS

A retrospective chart review of all vaginal PG E2-induced abortions at Westchester Medical Center between January 1996 and April 1998 was done. Only women who sought terminations between 18 and 24 weeks' gestation by prostaglandin induction were included. These abortions were predominantly secondary to fetal structural and chromosomal anomalies. The study population was subdivided into groups based on the use of pretreatment cardiac puncture with potassium chloride. The groups were compared for maternal, fetal, and procedural characteristics. The chi2 test, Student t test, and Wilcoxon rank-sum test were used for analysis.

RESULTS

There were no differences between the cardiac puncture and control groups when compared for various maternal and procedural characteristics, fetal weight, and the need for curettage for retained products of conception. However, the required median doses of PG E2 and the initiation to expulsion interval were significantly lower in the cardiac puncture group compared with the control group (2.0 doses compared with 3.0 doses, P<.001; 570 minutes compared with 890 minutes, P = .006).

CONCLUSION

Pretreatment-induced fetal death significantly reduced the interval to expulsion and doses of PG E2 required for late second-trimester abortion.

Perinatal outcome of triplet gestation: does prophylactic cerclage make a difference?

OBJECTIVE

To compare the perinatal outcome of triplet gestations with and without prophylactic cerclage.

METHODS

A retrospective chart review of all triplet gestations delivered between January 1988 and June 1997 was performed. Only women initiating prenatal care before 15 weeks gestation were included. The cerclage group was compared to the no-cerclage group for maternal and perinatal outcome variables. Student t-test, Chi-square, and Fisher's exact test were used for analysis.

RESULTS

Twenty of the 59 (33.8%) sets of triplet gestations had prophylactic cerclage. There were no differences between groups when compared for maternal age, parity, preterm labor rate, gestational diabetes, anemia, antenatal steroid use, histologic chorioamnionitis, and postoperative endometritis. In addition, there were no differences in mean birth weight, Apgar scores, respiratory distress syndrome (RDS), intraventricular hemorrhage/periventricular leucomalacia (IVH/PVL), and neonatal mortality. Although the mean gestational age at delivery for the cerclage group (32.8+/-2.4 weeks) was not different from the no-cerclage group (31.5+/-3.6 weeks), the proportion of pregnancies delivered at 31 weeks or more, and at 32 weeks or more, was significantly higher in the cerclage group (90 vs. 62%, P = .02; 80 vs. 54%, P = .05), respectively. In addition, the incidence of extremely low birth weight (LBW) was significantly decreased in the cerclage compared with the no-cerclage group (1.7 vs. 15.4%, P = .005).

CONCLUSIONS

Prophylactic cerclage decreased significantly the incidence of extremely LBW neonates in triplet pregnancies. The proportion of neonates delivered at 31 weeks or more, and at 32 weeks or more was higher in the cerclage group.

Effectiveness of antenatal steroids in obstetric subgroups

OBJECTIVE

To determine the effectiveness of antenatal steroids in the reduction of neonatal morbidity and mortality in obstetric subgroups of preterm labor with intact membranes, preterm premature rupture of membranes (PROM), and pregnancy-associated hypertension. The secondary objective was to determine the effect of antenatal steroids in appropriate for gestational age (AGA) and growth-restricted neonates.

METHODS

We studied the neonatal outcomes for all women who delivered infants weighing 1750 g or less at birth between January 1990 and July 1997 at our institution. The study population was divided primarily into three clinical groups: preterm labor with intact membranes, PROM, and pregnancy-associated hypertension. Secondarily, the total population was divided based on birth weight and gestational age into AGA and growth-restricted neonates. Within each obstetric subgroup, neonates exposed to antenatal steroids were compared with unexposed neonates for respiratory distress syndrome (RDS), intraventricular hemorrhage and periventricular leukomalacia, the incidence of major brain lesions, necrotizing enterocolitis, proved neonatal sepsis, patent ductus arteriosus, and neonatal death. The subgroups were also compared for gestational age at delivery, birth weight, birth weight percentile, Apgar scores, postnatal surfactant exposure, and clinical and histologic chorioamnionitis. Descriptive statistics, Student t test, chi2, Fisher exact test, and logistic regression were used for analysis.

RESULTS

A total of 1148 neonates weighing 1750 g or less were delivered during the study period. There were 447 and 410 neonates delivered after preterm labor with intact membranes and PROM, respectively, and 245 neonates born to mothers with pregnancy-associated hypertension. Nine hundred twenty-eight neonates were AGA and the remaining 220 neonates were growth restricted. Antenatal steroids significantly decreased the incidence of RDS, the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia, necrotizing enterocolitis, and neonatal mortality in preterm labor with intact membranes. In the presence of PROM, it significantly decreased the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia and decreased neonatal mortality, with no apparent effect on the incidence of RDS. Antenatal steroids did not show any beneficial effect in pregnancy-associated hypertension and fetal growth restriction (FGR). Additionally, a significant increase was observed in the incidence of proved neonatal sepsis when antenatal steroids were used in pregnancy-associated hypertension.

CONCLUSION

The effectiveness of antenatal steroids varies with the obstetric population studied. Antenatal steroids significantly decreased the incidence of major neonatal morbidity and mortality in the AGA preterm neonate delivered after preterm labor with intact membranes. Antenatal steroids did not show any benefit in cases of pregnancy associated with maternal hypertension or FGR. Its effect in the presence of PROM is limited to a significant reduction in the incidence and severity of intraventricular hemorrhage and periventricular leukomalacia and in neonatal death.

Amniotic fluid neuron-specific enolase: a role in predicting neonatal neurologic injury?

OBJECTIVE

To determine the relationship between amniotic fluid (AF) neuron-specific enolase and the development of neonatal intraventricular hemorrhage and periventricular leucomalacia.

METHODS

Thirty-nine AF samples, obtained from women in preterm labor between 24 and 32 weeks' gestation, were analyzed for neuron-specific enolase. All women delivered preterm neonates who had neurosonograms on the 3rd and 7th days of life. The results of the neurosonograms were used to divide the study population first into normal and abnormal groups, then into normal, minor, and major brain lesion groups. The groups were compared for the median neuron-specific enolase, proportion with values of 6 microg/L or more, and other demographic characteristics.

RESULTS

There were no differences between the groups' maternal and neonatal characteristics. However, the abnormal group had significantly higher median value of neuron-specific enolase than the normal group (9.5 microg/L and 2.0 microg/L, respectively; P < .001). The median neuron-specific enolase levels for the major, minor, and normal groups were 9.75 microg/L, 6.5 microg/L and 2.0 microg/L, respectively (P < .001). The optimum cutoff point, with a sensitivity of 89% and specificity of 100%, was 6 microg/L; 89% of the abnormals had values of 6 microg/L or more, compared with none of the normals (P < .001). The risk of developing intraventricular hemorrhage or periventricular leucomalacia was 11.5 times greater when AF neuron-specific enolase levels were 6 microg/L or more.

CONCLUSION

Amniotic fluid neuron-specific enolase is a useful marker of neonatal neurologic injury.

Intra-amniotic pressure reduction in twin-twin transfusion syndrome

OBJECTIVE

Our purpose was to measure intra-amniotic pressure before and after decompression amniocentesis in twin-twin transfusion syndrome.

STUDY DESIGN

Intra-amniotic pressures were measured during decompression amniocentesis on 18 occasions in 5 pregnancies complicated by twin-twin transfusion syndrome. The intra-amniotic pressure was determined with a water manometer before and after removal of amniotic fluid. For comparison, intra-amniotic pressure was determined in 10 uncomplicated gestations.

RESULTS

Initial intra-amniotic pressures in twin-twin transfusion gestations (mean, 17.2 +/- 5.2 cm H2O; range, 5.5 to 33.0 cm H2O) were higher than those of the uncomplicated gestations (mean, 8.4 +/- 3.3 cm H2O; range, 3.5 to 13.5 cm H2O; p < 0.002). Intra-amniotic pressures following therapeutic amniocentesis (mean, 10.9 +/- 5.1 cm H2O; range, 3.5 to 23.0 cm H2O) were not different from those of the uncomplicated gestations (p = 0.16).

CONCLUSION

The intra-amniotic pressure in twin-twin transfusion gestations is higher than that of the uncomplicated gestation. Decompression amniocentesis reduces intra-amniotic pressure to that of the uncomplicated gestation.

Understanding and using confidence intervals in clinical research

Confidence intervals contain a wealth of clinically relevant information that is not available in the P value and usual significance testing. Numerous articles discuss the hazards of interpreting study results based solely on the P value, raising both practical and philosophical concerns. The general recommendation is that clinical research should not just test hypotheses, but also describe magnitudes of clinical effect. To this end, the confidence interval is a crucial tool in interpreting clinical studies. In this report, we show how one may use confidence intervals to gain further insight into clinical research. For example, by using confidence intervals, one can identify statistically significant results that are clinically imprecise, or conversely, statistically nonsignificant results that are quite precise. In addition, confidence intervals, like the P value, are influenced by sample size. We show how sample sizes that are sufficiently large to test hypotheses may be too small to generate precise estimates of the magnitude of effect. The application and interpretation of confidence intervals are demonstrated through the use of several examples.

Amniotic fluid complement C3 as a marker of intra-amniotic infection

OBJECTIVE

To determine the value of amniotic fluid (AF) complement C3 as a marker of intra-amniotic infection and to compare complement C3 with other rapid markers of intra-amniotic infection.

METHODS

One hundred four women with singleton gestations, in preterm labor with intact membranes, at 23-35 weeks' gestation underwent transabdominal amniocentesis. Amniotic fluid was analyzed for white blood cell (WBC) count, lactate dehydrogenase (LDH), glucose, Gram stain, and complement C3. Cultures for aerobes, anaerobes, and mycoplasma species also were performed. The median values of complement C3, WBC, LDH, and glucose were compared between the culture-positive and -negative groups. Complement C3 was compared with WBC count, LDH, glucose, and Gram stain for sensitivity, specificity, positive and negative predictive values, and accuracy in the prediction of a positive AF culture. Descriptive statistics, receiver operating characteristic curve, Fisher exact test, and Wilcoxon rank-sum test were used for analysis.

RESULTS

The prevalence of positive cultures was 11.5% (12 of 104). The culture-positive group had a significantly higher median C3 (7.0 mg/dL) than the median C3 (3.0 mg/dL) of the culture-negative group (P < .001). Also, the median values of WBC (1120.5 cells/mm3) and LDH (2697 U/L) were significantly higher and the median glucose (6.5 mg/dL) was significantly lower among women with positive AF cultures than among women with negative AF cultures (WBC=1 cell/mm3; LDH=165 U/L; glucose=45 mg/dL; P < .001). Eleven of the 12 culture-positive cases had a C3 of 5 mg/dL or more, whereas four of the 92 culture-negative cases had a C3 of 5 mg/dL (P < .001). Nine of the 12 culture-positive cases but none of the 92 culture-negative cases had a C3 of 6 mg/dL or more (P < .001). The relative risks of a positive AF culture were 65.27 (95% confidence interval [CI] 9.08, 469.27) and 31.67 (95% CI 10.40, 96.43) times greater among women with AF complement C3 levels of 5 and 6 mg/dL or more, respectively. Depending on the cutoff point used, complement C3 had similar or higher sensitivity, specificity, positive predictive value, and negative predictive value for intra-amniotic infection when compared with WBC count, LDH, glucose and Gram stain.

CONCLUSION

Amniotic fluid complement C3 has value in the diagnosis of intra-amniotic infection in preterm labor with intact membranes. Complement C3 is available readily and compares favorably with other rapid markers of AF infection. This study supports the general concept of fetal inflammatory response to microbial invasion of AF.

Seronegativity to varicella-zoster virus in a tertiary care obstetric population

OBJECTIVE

To determine the seronegativity rate of varicella-zoster virus in a tertiary care obstetric population.

METHODS

At their initial prenatal visit, all obstetric patients at Westchester County Medical Center have a varicella-zoster virus IgG antibody titer (Varicella Stat; Biowhittaker, Inc., Walkersville, MD) performed. A value of 0.99 or greater units is positive. Patients were divided into three groups: seronegative, seropositive, and those with no test results. Mean maternal age was compared among groups using the unpaired two-tailed Student t test, with P < .05 considered significant.

RESULTS

From February 1, 1994, to May 30, 1996, 927 women had an initial prenatal visit. Ninety-nine patients were varicella-zoster virus antibody negative (seronegativity 11.6%, which is significantly higher than that reported in other studies); 755 were varicella-zoster virus antibody positive, and 73 had no results. The mean age of the seronegative patients was 27 years and of the seropositive patients 28 years, which was not significantly different.

CONCLUSION

Varicella-zoster virus seronegativity is higher in our obstetric population than generally is reported in adults. This may reflect the number of immigrants from tropical countries attending metropolitan hospitals. Mathematic models evaluating the impact of varicella-zoster virus vaccination and decisions regarding screening and postpartum vaccination must be based on accurate epidemiologic data, particularly in view of the effect of varicella-zoster virus on pregnant women, their fetuses, and their neonates.

Correlation of neonatal nucleated red blood cell counts in preterm infants with histologic chorioamnionitis

OBJECTIVE

The aim of this study was to compare the neonatal nucleated red blood cell counts in preterm infants in the presence and absence of clinical and histologic chorioamnionitis while controlling for gestational age and birth weight percentile.

STUDY DESIGN

Nucleated red blood cell counts were obtained from preterm infants delivered after preterm labor or preterm premature rupture of membranes. Patients were divided on the basis of clinical and histologic chorioamnionitis. Nucleated red blood cell counts between groups were compared, and regression analysis controlling for gestational age and birth weight percentile was performed.

RESULTS

Of 359 patients, both measures of infection status were significantly associated with increased nucleated red blood cell counts. In the regression analysis histologic chorioamnionitis retained significance, whereas clinical chorioamnionitis did not.

CONCLUSIONS

Histologic chorioamnionitis produces an erythropoietic response in the fetus. Whether fetal erythropoiesis is a direct response to mediators of inflammation or whether it is the result of a rise in erythropoietin is unknown.

Intrapartum assessment of fetal well-being: a comparison of scalp stimulation with scalp blood pH sampling

OBJECTIVE

To determine whether the need for fetal scalp pH sampling is decreased by the scalp stimulation test and whether redefinition of reactivity and presence of variability further decrease the need for scalp pH sampling.

METHODS

One hundred eight women with fetal heart rate (FHR) patterns suggestive of acidosis underwent fetal scalp blood pH evaluations. Digital scalp stimulation was performed for 15 seconds 1-2 minutes before pH sampling. The study group was subdivided based on reactivity to scalp stimulation and scalp puncture and was correlated with pH values. Reactivity was defined as an acceleration of 15 beats per minute or more lasting at least 15 seconds and redefined as an acceleration of 10 beats per minute or more lasting at least 10 seconds. Nonreactive responses were subdivided based on FHR variability preceding the scalp stimulation and were correlated with pH values. Fisher exact test was used for analysis.

RESULTS

All 51 instances of acceleration of 15 beats per minute or more lasting at least 15 seconds following scalp stimulation had a scalp pH of 7.20 or more. Using an acceleration of 10 beats per minute or more lasting at least 10 seconds, seven more reactive responses were obtained after scalp stimulation, all with pH of 7.20 or more. The 15 instances in which the pH was less than 7.20 were nonreactive irrespective of the definition of reactivity (P < .001). Twenty-one of the 50 instances of nonreactive responses (reactive response: acceleration of 10 beats per minute or more lasting at least 10 seconds) had positive variability. Only two of these 21 (9.5%) instances compared to 13 of the 29 (45%) instances with negative variability had pH less than 7.20 (P < .007).

CONCLUSIONS

The scalp stimulation test could decrease the need for fetal scalp blood sampling by 47%. Redefinition of reactivity could decrease the need for scalp sampling by 54%. In addition, assessment of FHR variability before scalp stimulation could decrease further the need for scalp blood sampling by 73%.

Obstetric antecedents of intraventricular hemorrhage and periventricular leukomalacia in the low-birth-weight neonate

OBJECTIVE

Neonatal intraventricular hemorrhage and periventricular leukomalacia have a strong correlation with eventual neurologic deficit. Our objective was to correlate obstetric factors with the development of these lesions.

STUDY DESIGN

Seven hundred forty-five consecutive inborn neonates with birth weights from 500 to 1750 gm were divided into three clinical groups: premature rupture of membranes, refractory preterm labor with intact membranes, and delivery initiated by the physician for maternal or fetal indications. Neonatal neurosonography was performed on days 3 and 7 of life and results were described as normal or abnormal. Abnormal scans included intraventricular hemorrhage seen within 3 days and echodense or echolucent periventricular leukomalacia seen within 7 days of life. Major abnormalities included intraventricular hemorrhage grades 3 and 4, intraventricular hemorrhage with periventricular leukomalacia, and echolucent periventricular leukomalacia. Abnormal scans were correlated with groups of origin and clinical and histologic chorioamnionitis.

RESULTS

Abnormal scans occurred in 33% of cases of premature rupture of membranes and in 38.9% of cases of preterm labor compared with 17.7% of physician-initiated cases (p < 0.000001). Major lesions occurred in 17.6% of cases of premature rupture of membranes, 21.4% of cases of preterm labor, and 1.1% of physician-initiated cases (p < 0.0000001). Clinical chorioamnionitis occurred in 19.7% of cases of premature rupture of membranes, 11.9% of cases of preterm labor, and 1.1% of physician-initiated cases (p < 0.001) and was associated with a significant increase in the incidence (p < or = 0.005) and severity (p < or = 0.007) of these lesions. Histologic chorioamnionitis occurred in 59.9% of cases of premature rupture of membranes, 43.2% of cases of preterm labor, and 8% of physician-initiated cases and did not correlate significantly with the incidence or severity of abnormal scans. These findings were independent of gestational age.

CONCLUSIONS

The incidence and severity of intraventricular hemorrhage and periventricular leukomalacia were significantly increased in premature rupture of membranes and preterm labor compared with the physician-initiated cases. Clinical chorioamnionitis increased the incidence and severity of these lesions.

A comparison of rapid amniotic fluid markers in the prediction of microbial invasion of the uterine cavity and preterm delivery

OBJECTIVE

The purpose of this study was to evaluate amniotic fluid lactate dehydrogenase level in comparison with other rapid markers in prediction of microbial invasion of the uterine cavity and preterm delivery < or = 36 hours after amniocentesis.

STUDY DESIGN

One hundred thirty-one women in preterm labor with intact membranes underwent transabdominal amniocentesis. Amniotic fluid was analyzed for leukocyte count, glucose level, lactate dehydrogenase level, and Gram stain. Cultures for aerobes, anaerobes, and Mycoplasma sp. were performed. Amniocentesis-to-delivery interval was calculated. The study group was divided and the findings compared according to amniotic fluid culture results and according to amniocentesis-to-delivery interval. Sensitivity, specificity, and positive and negative predictive value were calculated for lactate dehydrogenase, leukocyte count, glucose, and Gram stain in the prediction of positive amniotic fluid culture and preterm delivery < or = 36 hours after amniocentesis. Receiver-operator characteristic curve analysis, logistic regression analysis, t tests, and nonparametric tests were used.

RESULTS

The prevalence of positive amniotic fluid cultures was 12% (16 of 131). The median lactate dehydrogenase level (1084 U/L) was significantly greater for women with a positive amniotic fluid culture than for those with a negative culture (median lactate dehydrogenase level 194 U/L; p < 0.0002). The critical values calculated for optimal performance in prediction of a positive amniotic fluid culture were a lactate dehydrogenase level > or = 419 U/L, leukocyte count > or = 50 cells/mm3 (50 x 10(6)/L) and glucose < or = 17 mg/dl (0.94 mmol/L). Lactate dehydrogenase, leukocyte count, glucose, and Gram stain were equally sensitive and specific in prediction of a positive amniotic fluid culture. Thirty-nine women (29.8%) gave birth < or = 36 hours after amniocentesis. The median lactate dehydrogenase level (414 U/L) was significantly greater among women giving birth < or = 36 hours after amniocentesis than among women giving birth > 36 hours after amniocentesis (median lactate dehydrogenase, 173 U/L; p < 0.001). Critical values of lactate dehydrogenase > or = 225 U/L, leukocyte count > or = 10 cells/mm3 (10 x 10(6)/L) and glucose < or = 34 mg/dl (1.9 mmol/L) were selected for optimal performance in prediction of amniocentesis-to-delivery interval < or = 36 hours. Lactate dehydrogenase level had the best sensitivity (74%) in prediction of delivery < or = 36 hours after amniocentesis in contrast to leukocyte count (49%), glucose (62%), and positive Gram stain (26%). Amniotic fluid lactate dehydrogenase values > or = 225 U/L were associated with a fivefold greater risk for delivery < or = 36 hours after amniocentesis (odds ratio 5.46, 95% confidence interval 2.00 to 14.87; p = 0.0006).

CONCLUSION

Amniotic fluid lactate dehydrogenase level has diagnostic value in prediction of a positive amniotic fluid culture and delivery < or = 36 hours after amniocentesis. Lactate dehydrogenase is a readily available, inexpensive, rapid amniotic fluid marker that can be measured in any hospital laboratory.

Intrauterine transmission of hepatitis A virus

BACKGROUND

Hepatitis A is a common, self-limited disease transmitted by fecal-oral contamination.

CASE

A 23-year-old woman, para 2-0-0-2, developed hepatitis A at 20 weeks' gestation. At 27 weeks, ultrasound revealed polyhydramnios and fetal ascites. Hepatitis A immunoglobulin M antibody in fetal blood obtained by funipuncture confirmed acute hepatitis A infection in the fetus. Polyhydramnios and ascites persisted until 35 weeks, when the fetus developed ultrasound signs of meconium peritonitis, and delivery was accomplished uneventfully. Meconium peritonitis was diagnosed in the neonatal period and treated surgically.

CONCLUSION

To our knowledge, this is the first report of intrauterine transmission of hepatitis A. The disease presented with fetal ascites and was confirmed by positive fetal blood serology.

Acute myocardial infarction in pregnancy with subsequent medical and surgical management

BACKGROUND

Myocardial infarction is a rare event in pregnancy that requires medical stabilization with possible surgical interventions.

CASE

A 37-year-old woman developed an anterior wall myocardial infarction secondary to severe coronary artery disease during the early third trimester of pregnancy. The patient was managed with multiple modalities to stabilize her condition and prolong the gestation. The salient point in the management included: defibrillation and pharmacologic agents, intra-aortic balloon pump, coronary artery bypass graft surgery using a cardiopulmonary bypass pump while maintaining continuous fetal heart rate monitoring, and delivery of the neonate at term.

CONCLUSION

Aggressive management of this patient allowed continuation of pregnancy with good outcome for mother and neonate.

Relationship between neonatal nucleated red blood cell counts and hypoxic-ischemic injury

OBJECTIVE

To determine if nucleated red blood cell counts(RBC) are different in infants who develop intraventricular hemorrhage and periventricular leukomalacia in the first week of life and in those who do not.

METHODS

Nucleated RBCs were obtained from 441 infants weighing more than 499 g and less than 1751 g. Neonatal cranial fontanel sonography was performed on days 3 and 7 of life, and neonates were divided into those with normal and abnormal sonographic findings. The nucleated RBCs were compared between these groups and between normal and abnormal groups matched for birth weight and gestational age.

RESULTS

Mean gestational age, birth weight, birth weight percentile, Apgar score, respiratory distress syndrome and mortality were different between the infants with normal and abnormal ultrasound findings. The nucleated RBCs (per 100 white blood cells) were not different (40.5 +/- 126.8 versus 41.8 +/- 71.7, t = 0.09, P = .9). When we controlled for gestational age and birth weight, there was no significant difference between nucleated RBCs in those with normal and abnormal sonography (54.3 +/- 206.5 versus 41.4 +/- 72.0,t = 0.56, P = .6). In growth-restricted neonates, there was a significant increase in nucleated RBCs regardless of whether growth restriction was defined as tenth percentile or less, 25th percentile or less, or 50th percentile or less, even when we controlled for gestational age.

CONCLUSION

Nucleated RBCs are not different in preterm infants with or without intraventricular hemorrhage and periventricular leukomalacia, even when one controls for gestational age and birth weight. There are significant elevations in nucleated RBCs in growth-restricted fetuses. Birth weight percentile must be considered when using nucleated RBCs as a marker of intrauterine hypoxia.

Absence of relaxation to lactate in human placental vessels of pregnancies with severe preeclampsia

OBJECTIVE

Our objective was to determine whether the observed relaxation to lactate and other agents in placental vessels of normal pregnancies is altered in severe preeclampsia.

STUDY DESIGN

Isolated placental arteries and veins from women with severe preeclampsia and uncomplicated term pregnancies were precontracted with prostaglandin F2 alpha under 5% oxygen and 5% carbon dioxide with the balance nitrogen (Po2 35 to 38 torr) and then exposed to lactate (1 to 10 mmol/L, pH 7.4, n = 8 to 15), arachidonic acid (0.01 to 10 mumol/L, n = 6 to 13), nitroglycerin (1 nmol to 1 mumol/L, n = 4 to 12), or forskolin (0.01 to 10 mumol/L, n = 6 to 9). The response to lactate was also examined in placental vessels from appropriate-for-gestational-age preterm deliveries (n = 8) for comparison with a similar group with severe preeclampsia (n = 8). The t test and analysis of variance statistics were used.

RESULTS

Relaxation to lactate was markedly inhibited in both placental arteries and veins of women with severe preeclampsia compared with vessels from uncomplicated term or preterm pregnancies. Responses to the other relaxing agents were not altered in the severely preeclamptic vessels.

CONCLUSIONS

In severe preeclampsia absence of lactate-induced dilatation of placental vessels may contribute to the fetal complications associated with impaired blood flow and vasospasm.

Acute appendicitis in pregnancy and the occurrence of major intraventricular hemorrhage and periventricular leukomalacia

BACKGROUND

Infection and endotoxemia have been associated with neurologic injury in the newborn. In addition, recent reports have noted an increased incidence of fetal neurologic injury in the presence of intrauterine infection.

CASES

Three pregnancies complicated by acute appendicitis and refractory preterm labor resulting in the delivery of neonates who developed early major intraventricular hemorrhage and/or periventricular leukomalacia are described.

CONCLUSION

We hypothesize that extrauterine infections like acute appendicitis may play a role in the occurrence of neonatal neurologic injury.

Recurrent chorioamnionitis and second-trimester abortion because of an enterouterine fistula

BACKGROUND

Chorioamnionitis, a common cause of second-trimester abortion, is usually secondary to an ascending infection. Recurrent chorioamnionitis with second-trimester abortion secondary to an occult enterouterine fistula has not been reported previously.

CASE

A 26-year-old Indian woman, para 0-0-2-0, presented with two spontaneous second-trimester losses. Her third pregnancy carried to 24 weeks, but she delivered after the development of pneumonia, bacteremia, preterm labor, and chorioamnionitis. The patient passed melena containing blood clots after the delivery. After the last pregnancy, laparoscopy and laparotomy revealed an ileal-uterine fistula and a foreign body (necrotic cartilage). The blind loop of bowel was resected and the fistulous tract excised.

CONCLUSION

Our patient's recurrent pregnancy wastage was caused by chorioamnionitis secondary to an enterouterine fistula resulting from foreign body ingestion. A complete reversal of this problem is anticipated.

Epidemiologic predictors of hepatitis C virus infection in pregnant women

OBJECTIVE

To identify sensitive epidemiologic predictors of a positive hepatitis C virus antibody test in asymptomatic persons, and to compare the cost of testing only persons with an epidemiologic predictor to that of universal screening.

METHODS

Seventeen hundred consecutive pregnant women were tested by enzyme-linked immunosorbent assay for antibody to hepatitis C virus. Seventy-five subjects tested positive and were compared with 257 pregnant women who tested negative. Cohort and control patients were interviewed and their medical records were reviewed to identify those with chosen predictors of a positive hepatitis C virus antibody test.

RESULTS

Seventy-four of 75 cohort patients and 108 of 257 controls had one or more predictors of a positive antibody test. Cohort patients were significantly more likely (P < .001) to have the following: human immunodeficiency virus infection, a sex partner with a risk factor for hepatitis, age greater than 30 years, and a history of drug use, blood transfusion, sexually transmitted disease, hepatitis, or incarceration. The sensitivity and specificity of a single predictor in identifying a person with a positive test were 99 and 58%, respectively. The cost of finding a single individual with a positive antibody test by universal screening was $674, compared to $303 by selectively screening persons with one or more predictors of a positive antibody test.

CONCLUSIONS

Most individuals with positive hepatitis C virus antibody tests can be identified on the basis of epidemiologic predictors, reducing the cost of testing by 55%. These patients may receive appropriate medical therapy, and their children may be evaluated for possible infection by vertical transmission of hepatitis C virus.

Properties of a lactate-induced relaxation in human placental arteries and veins

OBJECTIVE

Our purpose was to determine the vasoactive effects and mechanism of action of lactate in human placental vessels by means of isometric muscle bath studies.

STUDY DESIGN

Isolated 1 to 2 mm human placental arteries and veins from normal term pregnancies, precontracted with prostaglandin F2 alpha and incubated under a PO2 of approximately 35 torr were exposed to lactate, 1 to 10 mmol/L, (pH 7.4), pyruvate, hydrogen peroxide, nitroglycerin, or forskolin. The effects of endothelium removal or inhibitors of cyclooxygenase (indomethacin 10 mumol/L) and L-arginine metabolism (nitro-L-arginine 30 mumol/L) on the response to lactate and the effects of an antagonist of guanylate cyclase activation (methylene blue 10 mumol/L), cyanide (1 mmol/L), and hypoxia (PO2 8-10 torr) on responses to all agents were determined by analysis of variance and t test statistics.

RESULTS

Lactate-elicited dose-dependent relaxation was not inhibited by endothelium removal, indomethacin, or nitro-L-arginine but was attenuated by methylene blue, cyanide, and hypoxia. Relaxation to hydrogen peroxide was inhibited by methylene blue and cyanide but not hypoxia. Relaxation to nitroglycerin was inhibited only by methylene blue, and relaxation to forskolin was not inhibited by these probes. Pyruvate did not produce a significant relaxation.

CONCLUSIONS

These findings suggest that lactate causes relaxation in the human placental vessels by an oxygen and cyclic guanosine-3':5'-monophosphate-dependent mechanism, which may involve the generation of hydrogen peroxide but not the metabolism of arginine. Lactate-induced dilatation may be of importance during labor and in situations of acute and chronic fetal hypoxia.

Gestational diabetes alters human placental vascular responses to changes in oxygen tension

OBJECTIVE

Our objective was to study tone responses caused by hypoxia, reoxygenation, and hydrogen peroxide in human placental vessels from gestational diabetic and normal term pregnancies.

STUDY DESIGN

Isolated placental arteries and veins from women with well-controlled gestational diabetic and uncomplicated term pregnancies were precontracted with U46619 under 5% oxygen/5% carbon dioxide/balance nitrogen (PO2 35 to 38 torr) and then exposed to hypoxia (95% nitrogen/5% carbon dioxide) atmosphere (PO2 8 to 10 torr) for 5 to 7 minutes followed by rapid reoxygenation. Cumulative doses of hydrogen peroxide (1 to 100 mumol/L) were added at 2-minute intervals. The studies were conducted in both the presence and the absence of endothelium. Prostaglandin involvement was examined by treatment with indomethacin. Analysis of variance and t test statistics were used.

RESULTS

After incubation under 5% oxygen, hypoxia caused a larger prostaglandin-independent relaxation in arteries and veins of women with gestational diabetes than in normal vessels. Placental vessels of women with gestational diabetes were found to undergo a significantly larger contraction than normal vessels when exposed to posthypoxic reoxygenation or micromolar concentrations of hydrogen peroxide. Both responses were eliminated and reversed to a relaxation by pretreatment with 10 mumol/L indomethacin in both gestational diabetic and normal vessels, consistent with mediation through the formation of prostaglandins. Removal of the endothelium did not appear to alter any of the observed responses.

CONCLUSIONS

Gestational diabetes produces an enhancement of the observed relaxation caused by hypoxia and the contraction produced by reoxygenation or hydrogen peroxide.

Didanosine (ddI) and zidovudine (ZDV) susceptibilities of human immunodeficiency virus (HIV) isolates from long-term recipients of ddI

Thirty HIV isolates, obtained from 15 patients before and after receiving single drug therapy with didanosine (ddI), were examined for sensitivity to ddI and zidovudine (ZDV) using a peripheral blood mononuclear leukocyte (PBML)-based assay. Fourteen of the patients had ARC, one had AIDS and 12 had received previous therapy with ZDV. After a median of 1 year of ddI therapy, isolates were significantly less sensitive to ddI than were isolates obtained prior to therapy (P = 0.03). A decrease in ddI sensitivity was observed in ten of the 15 isolate pairs. In contrast to ddI susceptibilities, sensitivity to ZDV increased over the same period of time (P = 0.03). Additional isolates were obtained from four patients who received ddI monotherapy for 2 years. Three of these isolates demonstrated no change in ddI sensitivity compared to baseline. No correlation could be made in this study between development of decreased ddI sensitivity and serum p24 levels, CD4 counts, or clinical outcome. Decreased ddI sensitivity occurs frequently among HIV isolates obtained from long-term recipients of ddI. This decreased sensitivity is modest in degree and is of unknown clinical significance.

Hydrogen peroxide and reoxygenation cause prostaglandin-mediated contraction of human placental arteries and veins

OBJECTIVE

Because our previous studies in several vascular preparations suggest that posthypoxic reoxygenation elicits tone responses by generation of hydrogen peroxide we compared the actions of reoxygenation and hydrogen peroxide on isolated human placental arteries and veins.

STUDY DESIGN

Endothelium-intact and denuded arteries and veins (1 to 2 mm diameter, from normal term deliveries), incubated under 95% oxygen/5% carbon dioxide or 5% oxygen/5% carbon dioxide (balance nitrogen) and precontracted with 1 to 10 nmol/L U46619, were exposed to hypoxia (95% nitrogen/5% carbon dioxide, PO2 8 to 10 torr) followed by reoxygenation and to 1 to 100 mumol/L hydrogen peroxide in the presence and absence of the inhibitor of prostaglandin biosynthesis, 10 mumol/L indomethacin.

RESULTS

In both arteries and veins posthypoxic reoxygenation or exposure to hydrogen peroxide produced vascular contraction that was eliminated or reversed to a modest relaxation by indomethacin, consistent with mediation by prostaglandins. Hypoxia after incubation with 5% oxygen, but not 95% oxygen, caused a modest prostaglandin-independent relaxation. Removal of the endothelium did not alter any of these responses.

CONCLUSION

Placental arteries and veins show a similar prostaglandin-mediated contraction to hydrogen peroxide and posthypoxic reoxygenation, consistent with a possible involvement of hydrogen peroxide in the response to reoxygenation.