Plaster cast burns: the reality.

An in vivo experimental study was performed of the temperatures produced by a setting plaster cast using hot and cold water. The results confirmed a statistical difference in the temperatures reached using hot and cold water. Forearm and below knee plasters did not represent a burn risk. Lower limb cylinder casts reached sufficient temperatures to cause burns with hot water but did not remain at these temperatures long enough to pose a clinical risk.

Effector sites in the three-dimensional structure of mammalian sperm beta-acrosin.

BACKGROUND: Proacrosin is a serine protease found specifically within the acrosomal vesicle of all mammalian spermatozoa. During fertilization proacrosin autoactivates to form beta-acrosin, in which there is a "light" chain cross-linked to a "heavy" chain by two disulphide bonds. beta-acrosin is thought to be multifunctional with roles in acrosomal exocytosis, as a receptor for zona pellucida proteins, and as a protease to facilitate penetration of spermatozoa into the egg. RESULTS: The crystal structures of both ram and boar beta-acrosins have been solved in complex with p-aminobenzamidine to 2.1 A and 2.9 A resolution, respectively. Both enzymes comprise a heavy chain with structural homology to trypsin, and a light chain covalently associated in a similar manner to blood coagulation enzymes. In crystals of boar beta-acrosin, the carboxyl terminus of the heavy chain is inserted into the active site of the neighboring molecule. In both enzyme structures, there are distinctive positively charged surface "patches" close to the active site, which associate with carbohydrate from adjacent molecules and also bind sulfate ions. CONCLUSIONS: From the three-dimensional structure of beta-acrosin, two separate effector sites are evident. First, proteolytic activity, believed to be important at various stages during fertilization, arises from the trypsin-like active site. Activity of this site may be autoregulated through intermolecular associations. Second, positively charged regions on the surface adjacent to the active site may act as receptors for binding zona pellucida glycoproteins. The spatial proximity of these two effector sites suggests there may be synergy between them.

Recognition of structurally diverse substrates by type II 3-hydroxyacyl-CoA dehydrogenase (HADH II)/amyloid-beta binding alcohol dehydrogenase (ABAD).

Human type II hydroxyacyl-CoA dehydrogenase/amyloid-beta binding alcohol dehydrogenase (HADH II/ABAD) is an oxidoreductase whose salient features include broad substrate specificity, encompassing 3-hydroxyacyl-CoA derivatives, hydroxysteroids, alcohols and beta-hydroxybutyrate, and the capacity to bind amyloid-beta peptide, leading to propagation of amyloid-induced cell stress. In this study, we examine the structure and enzymatic activity of the homologous rat HADH II/ABAD enzyme. We report the crystal structure of rat HADH II/ABAD as a binary complex with its NADH cofactor to 2.0 A resolution, as a ternary complex with NAD(+) and 3-ketobutyrate (acetoacetate) to 1.4 A resolution, and as a ternary complex with NADH and 17 beta-estradiol to 1.7 A resolution. This first crystal structure of an HADH II confirms these enzymes are closely related to the short-chain hydroxysteroid dehydrogenases and differ substantially from the classic, type I 3-hydroxyacyl-CoA dehydrogenases. Binding of the ketobutyrate substrate is accompanied by closure of the active site specificity loop, whereas the steroid substrate does not appear to require closure for binding. Despite the different chemical nature of the two bound substrates, the presentation of chemical groups within the active site of each complex is remarkably similar, allowing a general mechanism for catalytic activity to be proposed. There is a characteristic extension to the active site that is likely to accommodate the CoA moiety of 3-hydroxyacyl-CoA substrates. Rat HADH II/ABAD also binds amyloid-beta (1-40) peptide with a K(D) of 21 nM, which is similar to the interaction exhibited between this peptide and human HADH II/ABAD. These studies provide the first structural insights into HADH II/ABAD interaction with its substrates, and indicate the relevance of the rodent enzyme and associated rodent models for analysis of HADH II/ABAD's physiologic and pathophysiologic properties.

Practical use and efficiency of amniotic fluid OD 650 as a predictor of fetal pulmonary maturity.

Fetal pulmonary maturity evaluation was performed on 237 amniotic fluid specimens from 202 gravidas using: 1) optical density (OD) 650, 2) shake or foam stabilization test, and 3) lecithin: sphingomyelin ratio. One hundred thirty-one gravidas delivered within 48 hours of specimen collection, including nine of 11 women delivering respiratory distress syndrome-affected infants and 40 delivering premature infants. The efficiency of each test in predicting fetal pulmonary maturity status was calculated and showed that statistically, OD 650 was significantly better at predicting fetal pulmonary maturity in preterm infants and all infants. Twenty-six of 27 infants of diabetic mothers (classes A through R) had mature OD 650 values; none developed respiratory distress syndrome. The authors confirm that the OD 650 is reliable in most clinical settings and superior to the shake test. The authors recommended its primary use when sophisticated phospholipid studies are not immediately available.

Effect of maternal weight gain on fetal, infant, and childhood death and on cognitive development.

The effect of maternal weight gain during pregnancy on fetal, infant, and childhood death and on cognitive development was analyzed by examining the conception products of 2590 women who participated in the Child Health and Development Studies of the School of Public Health, University of California, Berkeley. Although there was a strong inverse association between maternal weight gain and fetal and neonatal death, the implications of this are uncertain and are herein discussed. When the analysis was confined to pregnancies with gestational periods greater than 35 weeks, there was no effect of maternal weight gain on fetal, neonatal, infant, or childhood death. Children whose mothers gained between 5 and 29 lb during their pregnancy scored higher on the Raven Coloured Progressive Matrices test at age 5 than did those whose mothers gained less than 5 or more than 29 lb. Within the 5- to 29-lb group there were no significant differences in test scores among the different categories of maternal weight gain.

Plasma unconjugated estriol as an indicator of fetal dysmaturity in postterm pregnancy.

The role of twice-weekly plasma unconjugated estriol determinations in the prediction of fetal dysmaturity was studied in 663 patients seen at the Postdates Clinic of the Los Angeles County/University of Southern California Medical Center. The correlation between estriol and gestational age was - 0.055. According to the criteria of the Postdates Clinic protocol, sensitivity, specificity, predictive values of positive results, and those of negative results of estriol determinations in predicting fetal dysmaturity were 44.4, 80.6, 32.9, and 87.1%, respectively. The major deficiency of this test for the detection of fetal dysmaturity was in the less-than-ideal predictive value of a negative result: 13% of patients who had normal estriol values had dysmature infants. When estriol was less than 12 ng/ml and the value fell more than 20% from the previous level, the predictive value of fetal dysmaturity was 56%. In these circumstances, the termination of pregnancy is a reasonable consideration. Until a more sensitive test for fetal dysmaturity is developed, plasma unconjugated estriol determination will retain its role as a screening test in managing postterm pregnancies in a large obstetric population.

The bupivacaine paracervical block in labor and its effect on quantitative uterine activity.

This study utilized internal fetal monitoring and an on-line voltage control oscillator for measurement of uterine activity unit (UAU) determination in patients who received a paracervical block (PCB) with the use of bupivacaine hydrochloride (Marcaine). The total dose of 25 mg (5 cc/side) of 0.25% bupivacaine used for PCB in 32 patients produced no ill effects to the fetus, as reflected by baseline fetal heart rate (FHR), beat-to-beat variablity, or Apgar scores. No adverse maternal effects were noted, and anesthesia was rated good or excellent in 81% of patients. Rate of cervical dilation remained the same or increased in 29 of 32 patients. Quantitative UAUs showed a significant decrease in the third 10-minute interval after block in primiparas, but no significant change in multiparas or in the group taken as a whole. Total UAUs before versus after PCB for either group or taken together were not statistically different. A decreasing trend in UAUs after PCB versus a positive regression line from activity prior to the block was noted.

Management of post-term pregnancy in a large obstetric population.

A practical management protocol to handle the large volume of post-term gestations at the Los Angeles County/University of Southern California Medical Center was introduced and evaluated in 880 patients seen between March 1, 1979, and February 29, 1980. The protocol divided patients into 2 groups based on substantiated "good" or unsubstantiated "poor" obstetric dates. After clinical examinations, the primary screening test used was twice weekly plasma unconjugated estriol (E3) determinations. Antepartum fetal heart rate testing, in the form of nonstress tests, was used initially in the good obstetric dates group, and then done twice weekly only if the E3 value was abnormal (less than 18 ng/ml with good obstetric dates and less than 12 ng/ml with poor obstetric dates). Patients with good obstetric dates were delivered electively at more than 42 weeks' gestation if the cervix was favorable (Bishop score 9 or greater); otherwise, intervention occurred only with abnormal tests and a positive or suspicious contraction stress test, or with other medical indications. Only 8 perinatal losses (3 neonatal deaths and 5 stillbirths) occurred in 880 patients. Each of these patients received a follow-up evaluation: 3 had severe congenital anomalies, and 5 deaths occurred in patients who did not comply with the protocol. The cesarean section rate was 15.8%.

Single-dose cefazolin versus cefonicid for antibiotic prophylaxis in cesarean delivery.

The purpose of this prospective investigation was to compare a single intravenous dose of cefazolin to a single dose of cefonicid as prophylaxis for women having unscheduled cesarean delivery. In a double-blind, randomized design, 96 patients were assigned to receive a 1-g dose of cefazolin and 103 patients were designated to receive a 1-g dose of cefonicid. The antibiotics were administered after delivery of the infant. The two groups were comparable with respect to recognized risk factors for postcesarean infection. There were no statistically significant differences between the groups in the incidence of standard febrile morbidity, endomyometritis, urinary tract infection, wound infection, and bacteremia. There were also no significant differences between the groups in the fever index or the duration of hospitalization. We conclude that cefazolin and cefonicid provide a similar degree of prophylaxis against infection in patients having unscheduled cesarean delivery.

Outcome of trial of labor in patients with a single previous low transverse cesarean section for dystocia.

The purpose of this prospective investigation was to evaluate the outcome of trial of labor in women with a history of a single low transverse cesarean section for dystocia in comparison with the outcome in women with a history of cesarean delivery for a reason other than dystocia. During the study period, 89 of 131 patients (68%) with a history of dystocia had a successful trial of labor, compared with 78 of 96 women (81%) who had cesarean delivery for a reason other than dystocia (P less than .025). Within the former group, 79% of women who originally had surgery while still in the latent phase of labor had a successful trial of labor, compared with 61% (.05 less than P less than .10) of patients who had an arrest of dilation in the active phase of labor and 65% (not significant) of those who had an arrest of descent. The only serious complication among study patients was a single instance of uterine scar dehiscence (0.5%). We conclude that approximately two-thirds of patients with a previous cesarean delivery for dystocia will have a successful trial of labor. Of these women, those individuals whose initial operation was performed in the latent phase of labor appear to have the best prognosis for subsequent vaginal delivery.

Screening for illicit drug use in a military obstetric population.

The purpose of our investigation was to determine the prevalence of illicit drug use within our socioeconomically heterogeneous obstetric population, in order to assess the need for institution of universal screening. Five hundred consecutive new obstetric registrants had urine collected for routine culture. Following removal of a small aliquot of urine for culture, the samples were sent to the Armed Forces Institute of Pathology, Division of Forensic Toxicology. Each specimen was screened for the presence of alcohol, cocaine metabolites, cannabinoids, opiates, and amphetamines using fluorescent polarization immunoassay techniques. All positive screening tests were confirmed by gas chromatography mass spectrometry. Thirty samples were either lost in processing or of insufficient quantity to test. Five of the 470 samples (1.06%) tested were positive. One subject was taking prescription narcotics, so the correlated prevalence was 0.85%. Three tested positive for tetrahydrocannabinol and two for opiates. Analysis of our data demonstrates that our obstetric population has a significantly lower prevalence of illicit drug use than other populations reported previously (P less than .01). We recommend that each institution providing obstetric services determine its specific prevalence of illicit drug use.

Randomized comparison of five irrigation solutions at cesarean section.

A randomized double-blind study was undertaken to determine which irrigation solution might be best at cesarean section. A saline placebo was compared with ampicillin sodium and one each of three generations of cephalosporins: cephapirin sodium, cefamandole nafate, and moxalactam disodium. A total of 360 cesarean sections were studied, and comparisons made between antibiotic and control groups relative to demographics, possible risk factors, and multiple measures of postoperative morbidity. The total group was further divided into high- and low-risk labor and repeat cesarean groups. Post-cesarean endometritis was diagnosed in the following frequencies for the group as a whole: placebo (24.6%), ampicillin sodium (8.5%), cephapirin sodium (11.4%), cefamandole nafate (4.6%), and moxalactam disodium (16.4%). Cefamandole nafate consistently demonstrated significant decreases in endometritis and other morbidity measures versus placebo both in laboring patients and the group as a whole.

Reliability of fetal buttock blood sampling in assessing the acid-base balance of the breech fetus.

This prospective investigation was undertaken to compare fetal buttock capillary blood pH and umbilical artery and vein pH in fetuses presenting by the breech. The study group comprised ten term patients with singleton fetuses in the frank breech presentation who met established criteria for vaginal breech delivery. All patients had a normal labor pattern. Eight fetuses had a normal fetal heart rate tracing and two had severe variable decelerations during the second stage of labor. We obtained capillary blood for pH measurement from the fetal buttock within 15 minutes of delivery. Immediately after delivery, we collected arterial and venous blood samples from the umbilical cord for measurement of pH. In all fetuses, there was a highly significant correlation between fetal buttock capillary blood pH and umbilical artery pH (r = 0.96; P less than .001) and umbilical vein pH (r = 0.88; P less than .001). We conclude that measurement of pH in capillary blood obtained from the fetal buttock provides accurate assessment of the acid-base status of the breech fetus.

Risk of chromosomal abnormalities in patients with idiopathic polyhydramnios.

This prospective investigation was designed to assess the incidence of chromosomal abnormalities in patients with idiopathic polyhydramnios. Polyhydramnios was defined as 25 cm or greater in total vertical height in all four quadrants (amniotic fluid index) in any nonreferral patient (ie, primary care population) undergoing sonographic examination with a singleton pregnancy, normal fetal anatomical survey, normal glucose screening, and negative antibody screen. During the 2-year period from May 1, 1988 through April 30, 1990, 5038 gravidas delivered at Madigan Army Hospital Center. Unexplained polyhydramnios was detected sonographically in 125 patients, an incidence of 2.5%. After obtaining informed written consent, amniocentesis was performed in all patients. Within this group (N = 125), four chromosomal abnormalities (incidence of 3.2%) were detected. There were two trisomy 18 and two trisomy 21 fetuses. None of the four patients had maternal serum alpha-fetoprotein screening performed. The incidence of aneuploidy in patients with idiopathic polyhydramnios (3.2%) is much higher than the reported incidence of major karyotype abnormalities in live births (0.59%). We conclude that fetal chromosomal analysis should be considered in all obstetric patients with sonographic evidence of idiopathic polyhydramnios.

Placenta accreta: changing clinical aspects and outcome.

In an effort to determine if a changing clinical picture for placenta accreta exists in the late 1970s, 22 cases from January 1, 1975, to May 30, 1979, at Los Angeles County/University of Southern California (LAC/USC) Medical Center were reviewed. An incidence of clinically diagnosed placenta accreta of 1 per 2562 deliveries for all cases and 1 per 4027 for pathologically confirmed cases (ie, hysterectomy specimens) was found. Mean age of the patients was 29.5 years, and mean gravidity, parity, and abortion were 3.4, 2, and 0.27, respectively. Placenta previa was found in 14 patients (63.6%), 6 of whom had previously undergone cesarean section. No obvious etiology was found in 1 patient. Sixteen patients underwent cesarean section. Hysterectomy was performed on 14 patients, and conservative measures were employed in 8 patients. One maternal death (4.5%) occurred, but there was no perinatal mortality. The clinical picture of placenta accreta today is one of higher reported incidence, lower parity, greater incidence of associated placenta previa, individualized management, and decreasing maternal and perinatal mortality.

Urinary bladder distention: effect on labor and uterine activity.

To study quantitatively the effect of urinary bladder distention on labor and uterine activity, 68 patients requiring catheterization were studied. All patients were in the active phase of labor and had transcervical intrauterine pressure monitoring. Patients were studied in the same lateral position for 30 minutes before and after a catheterization interval, during which time uterine activity units were quantitated on line and changes were noted in cervical dilation and station and contraction frequency and tonus. Results were analyzed for the entire study group, for individual patients, and by urine volumes (10 to 550 ml) obtained at catheterization. Total uterine activity units increased in 43 patients and decreased in 25 after catheterization, but when compared with expected increases calculated from the slopes of the precatheterization interval in individual patients, there were 36 increases and 32 decreases. Individual slopes of uterine activity increased in 36 and decreased in 31 cases. There were no differences when the data were analyzed by urine volume, parity, or bith weight except possibly at large volumes. Changes in rates of cervical dilation and descent of the presenting part conform to the expected normal labor pattern. Within the limits of this study, emptying the urinary bladder has no effect on the course of labor or uterine activity based on the dynamic model of labor.

The effect of internal fetal monitoring on maternal infection following cesarean section.

A retrospective review of 300 cesarean sections was performed. Patients with internal fetal monitoring were at no greater risk for infection than were those patients with labor and rupture of membranes but without internal monitoring. However, the combination of rupture of membranes and labor was a major risk factor for both the frequency and severity of maternal infection after cesarean section. Once membranes are ruptured, we find no contraindication to the use of internal monitoring.

Antenatal hospitalization among enlisted servicewomen, 1987-1990.

OBJECTIVE: To describe the prevalence of, and indications for, antenatal hospitalization among women who delivered live and stillborn infants. METHODS: We reviewed the records of a cohort of 1825 black and white enlisted women who delivered from 1987-1990 at the four largest Army medical centers in the United States. Women with multiple gestations and those whose pregnancies ended before 20 weeks' gestation were excluded. Records of all women with preterm deliveries and a one-third sample of women with term deliveries were abstracted. RESULTS: Overall, 26.8 +/- 1.6% (mean +/- standard error) of the women were hospitalized antenatally. Of the estimated 702 antenatal hospitalizations, 44.0 +/- 3.4% were related to preterm labor, 10.3 +/- 1.9% to preeclampsia, 5.5 +/- 1.5% to hyperemesis, and 4.7 +/- 1.5% to urinary tract or kidney infection. The prevalence of hospitalization was lowest before 20 weeks (5.0 +/- 0.8%) and highest at 33-36 weeks (12.2 +/- 1.2%). Small and probably clinically insignificant differences between black and white women were noted in the overall prevalence of antenatal hospitalization and in the indications for hospitalization. CONCLUSION: As measured by hospitalization, severe antenatal morbidity is common in this population of healthy enlisted women.

The association of antiphospholipid antibodies with pregnancies complicated by fetal growth restriction.

The association of antiphospholipid antibodies with fetal growth restriction is often cited, but the published evidence for this is based on few patients and comes primarily from patient histories, not study groups. In this prospective study, we evaluated a subgroup of our population with fetuses whose estimated weights at ultrasound were at or below the tenth percentile for gestational age. Plasma and serum testing was performed to determine the presence of antiphospholipid antibodies, specifically lupus anticoagulant and anticardiolipin antibodies, respectively. From March 1990 through March 1991, 55 women were followed for suspected fetal growth restriction. Intensive monitoring of the fetal condition and modification of the mother's activity were recommended, resulting in 100% compliance. Despite this, 37 newborns were confirmed by birth weight to be at or below the tenth percentile, and all were below the 45th percentile. Fifteen of 55 women (27%) were positive for anticardiolipin antibodies, as were nine of 37 (24%) with correctly diagnosed fetal growth restriction. Five of 15 women whose newborns had ponderal indexes below the tenth percentile tested positive for anticardiolipin antibodies. None of the women had a positive lupus anticoagulant test. The prevalence of anticardiolipin antibodies in this study group was significantly higher than in our general population. We conclude that there is a statistically significant association between the presence of circulating maternal anticardiolipin antibodies and fetal growth restriction.

Computed tomographic pelvimetry in the evaluation of breech presentation.

The purpose of this investigation was to assess computed tomographic (CT) pelvimetry in the evaluation of breech presentation for trial of labor. Thirty-two patients with singleton term breech deliveries formed the study group. Seventeen of the 32 (53.1%) patients fulfilled the criteria for attempted vaginal delivery. Fourteen of the 17 (82.4%) delivered vaginally. All infants so delivered had five-minute Apgar scores greater than or equal to 7. Three of the 17 patients required abdominal delivery: one for fetal distress and two for arrest of dilation. These results compare favorably with studies using conventional x-ray pelvimetry. The advantages of CT over conventional pelvimetry include ease of performance, ease of interpretation, and decreased radiation dose to the fetus.