Video-tracked Anopheles arabiensis entry and exit behaviour at washed and damaged pyrethroid-treated bednets.

Insecticide-treated nets (ITNs) are the most effective method for malaria prevention in Africa. Using near-infrared video tracking in a laboratory environment, we recorded and assessed bednet entry and exit by a northern Tanzanian population of Anopheles arabiensis at a human-occupied untreated net and a PermaNet® 2.0 ITN. Both had 12 holes, each 10 cm in diameter, punctured at specific locations, and the ITN was washed 20 times to further simulate the wear and tear of ageing. Washing reduced the insecticide content of ITNs by 61%, which then showed similar rates to the untreated nets for net entry (39% entered untreated net and 41% entered ITN; p = 0.84) and exit (37% and 43%, respectively; p = 0.67). Regardless of treatment, approximately 40% of mosquitoes entered nets within 20 s of first appearing in the field of view and reached the volunteer's skin within 5 s of entering the net. Mortality rates post-exposure were significantly higher (p = 0.048) at ITNs (26.6%; 95% CI 13.4%-39.7%) than at untreated controls (6.4%; 95% CI 1.8%-14.6%). The washed and aged ITN provided little additional personal protection for the sleeper over an untreated net. Simple adjustments to materials and design that could extend the effective lifespan of ITNs are discussed.

The miR-106b-25 cluster mediates breast tumor initiation through activation of NOTCH1 via direct repression of NEDD4L.

Tumor-initiating cells (TIC) represent a subset of tumor cells with increased self-renewal capability. TICs display resistance to frontline cancer treatment and retain the ability to repopulate a tumor after therapy, leading to cancer relapse. NOTCH signaling has been identified as an important driver of the TIC population, yet mechanisms governing regulation of this pathway in cancer remain to be fully elucidated. Here we identify a novel mechanism of NOTCH regulation and TIC induction in breast cancer via the miR-106b-25 miRNA cluster. We show that the miR-106b-25 cluster upregulates NOTCH1 in multiple breast cancer cell lines, representing both estrogen receptor (ER+) and triple negative breast cancer (TNBC) through direct repression of the E3 ubiquitin ligase, NEDD4L. We further show that upregulation of NOTCH1 is necessary for TIC induction downstream of miR-106b-25 in both ER + and TNBC breast cancer cells, and that re-expression of NEDD4L is sufficient to reverse miR106b-25-mediated NOTCH1 upregulation and TIC induction. Importantly, we demonstrate a significant positive correlation between miR-106b-25 and NOTCH1 protein, yet a significant inverse correlation between miR-106b-25 and NEDD4L mRNA in human breast cancer, suggesting a critical role for the miR106b-25/NEDD4L/NOTCH1 axis in the disease. Further, we show for the first time that NEDD4L expression alone is significantly associated with a better relapse-free prognosis for breast cancer patients. These data expand our knowledge of the mechanisms underlying NOTCH activation and TIC induction in breast cancer, and may provide new avenues for the development of therapies targeting this resistant subset of tumor cells.

Transplacental passage of clindamycin from mother to neonate.

OBJECTIVE: To evaluate maternal and neonatal cord blood levels at delivery in patients receiving 900 mg of clindamycin intravenous (IV) every 8 h. STUDY DESIGN: Prospective study consented every mother that entered labor with a positive group B streptococcal culture, a high-risk penicillin allergy, and sensitivity to clindamycin and erythromycin. Maternal and cord blood clindamycin levels were obtained at delivery. Time from last dose completion to delivery, number of doses administered and body mass index (BMI) were assessed. RESULTS: Twenty-three patients were consented. All maternal clindamycin values were therapeutic and 22 (96%) of the 23 cord blood samples were therapeutic. The mean maternal level was of 4.46 µg ml-1 (range of 0.7 to 8.4 µg ml-1). The mean cord blood level was 3.35 µg ml-1 (range of <0.5 to 6.4 µg ml-1). CONCLUSION: These data show that the current dosing recommendation of 900 mg of clindamycin IV every 8 h produces therapeutic maternal and cord blood levels.

A novel video-tracking system to quantify the behaviour of nocturnal mosquitoes attacking human hosts in the field.

Many vectors of malaria and other infections spend most of their adult life within human homes, the environment where they bloodfeed and rest, and where control has been most successful. Yet, knowledge of peri-domestic mosquito behaviour is limited, particularly how mosquitoes find and attack human hosts or how insecticides impact on behaviour. This is partly because technology for tracking mosquitoes in their natural habitats, traditional dwellings in disease-endemic countries, has never been available. We describe a sensing device that enables observation and recording of nocturnal mosquitoes attacking humans with or without a bed net, in the laboratory and in rural Africa. The device addresses requirements for sub-millimetre resolution over a 2.0 × 1.2 × 2.0 m volume while using minimum irradiance. Data processing strategies to extract individual mosquito trajectories and algorithms to describe behaviour during host/net interactions are introduced. Results from UK laboratory and Tanzanian field tests showed that Culex quinquefasciatus activity was higher and focused on the bed net roof when a human host was present, in colonized and wild populations. Both C. quinquefasciatus and Anopheles gambiae exhibited similar behavioural modes, with average flight velocities varying by less than 10%. The system offers considerable potential for investigations in vector biology and many other fields.

Algorithms for the automated analysis of cellular dynamics within living fungal colonies.

We present robust and efficient algorithms to automate the measurement of nuclear movement and germ tube extension rates in living fungal networks. The aim is to facilitate the understanding of the dynamics and regulation of nuclear migration in growing fungal colonies. The proposed methodology combines a cascade correlation filter to identify nuclear centers from which 2D nuclear velocities are determined and a level set algorithm for centerline extraction to monitor spore (conidial) germling growth. We show how the proposed cascaded filter improves spatial resolution in the presence of noise and is robust when fluorescently labeled nuclei with different intensities are in close proximity to each other. The performance of the filter is evaluated by simulation in comparison to the well known Rayleigh and Sparrow criteria, and experimental evidence is given from clusters of nuclei and nuclei undergoing mitotic division. The capabilities developed have enabled the robust and objective analysis of 10's of Gigabytes of image data that is being exploited by biological scientists.

The fetal heart monitor tracing in pregnancies complicated by a spontaneous umbilical cord hematoma.

The objective of this study is to present and describe the fetal heart rate appearance in pregnancies complicated by an antenatal spontaneous umbilical cord hematoma that resulted in a live birth. Three cases of antenatal spontaneous umbilical cord hematoma are described. All three patients presented with a complaint of decreased fetal movement. The fetal heart monitor tracings on admission are depicted and discussed. In all three cases, the fetal heart rate pattern showed decreased variability with an absence of accelerations. Decelerations were noted but were identified in 25% or less of the contractions and primarily with contractions that exceeded 90 s. Absent accelerations with minimal to absent variability, if caused by uteroplacental insufficiency, usually develop in the presence of recurrent decelerations. Absent accelerations with minimal to absent variability in the absence of recurrent decelerations may suggest other causes including aneuploidy or congenital cardiac or neurologic anomalies. Though rare, spontaneous umbilical cord hematoma can be added to the differential.

Person-centred planning: factors associated with successful outcomes for people with intellectual disabilities.

BACKGROUND: Recent research in the USA and UK indicates that person-centred planning (PCP) can lead to improvements in lifestyle-related outcomes for people with intellectual disabilities (ID). It is clear, however, that the introduction of PCP does not have an equal impact for all participants. The aim of the present paper was to identify factors associated with the probability of delivering a plan and with improvements in outcomes for those who did receive a plan. METHODS: Information on the life experiences of participants was collected over a period of approximately 2 years for a cohort of 93 adults with ID. RESULTS: There were powerful inequalities in both access to and the efficacy of PCP in relation to participant characteristics, contextual factors and elements of the PCP process. CONCLUSIONS: Results are discussed in relation to implications for policy and practice for increasing the effectiveness of PCP and reducing inequalities in the life experiences of people with ID.

Experiences in method development for the analysis of in vitro study solutions for content.

Effects of drugs on the cardiovascular system are required to be assessed as part of safety pharmacology, in particular using the in vitro Human Ether-a-go-go Related Gene Product (HERG) and Purkinje fibre studies and can be used to predict safety margins prior to administration to man. Recent International Conferences on Harmonization (ICH) regulations, draft ICHS7B guidelines, indicate that levels of drug in bath solutions used should be measured if quantitative data are to be obtained for the estimation of safety margins. To accurately measure drug concentrations in bath solutions, a validated analytical method is required. This method is required to be accurate, precise, specific, and robust, and due to the increased potency of new drugs, liquid chromatography with mass spectrometric detection (LC-MS) has become the method of choice. Recent experiences validating methods for the analysis of a wide range of drugs in bath solutions has presented a major issue regarding the solubility of some drugs in bath solutions. This has resulted in the requirement of a different approach to the analysis of, in particular, lipophilic drugs that has in turn highlighted the potential for the significant overestimation of the drug concentration in these bath solutions and therefore inaccurate calculation of safety margins.

Identifying poststreptococcal glomerulonephritis.

Expedient antimicrobial treatment of group A beta-hemolytic streptococcal tonsillopharyngitis prevents suppurative complications and rheumatic fever; however, timely therapy does not prevent acute poststreptococcal glomerulonephritis. Acute poststreptococcal glomerulonephritis is the most common form of postinfectious glomerulonephritis and a leading cause of acute and chronic renal failure in childhood. This article discusses clinical presentation, diagnostic workup, treatment, and prevention of poststreptococcal glomerulonephritis in adults and children in the primary care setting.

The presence of hepatitis B surface antigen and deoxyribonucleic acid in amniotic fluid and cord blood.

OBJECTIVE: It is uncertain whether neonatal infection with hepatitis B, despite treatment after delivery with immunoglobulin and vaccine, is the result of prior in utero transmission of the virus or treatment failure. Furthermore, the potential risk of hepatitis B transmission from the mother to the fetus at the time a genetic amniocentesis is performed is also a concern. In an attempt to better elucidate these controversies, amniotic fluid and cord blood specimens obtained from pregnant women positive for hepatitis B surface antigen were analyzed for the presence of hepatitis B surface antigen and hepatitis B deoxyribonucleic acid. STUDY DESIGN: This study was a prospective longitudinal analysis that identified hepatitis B surface antigen-positive patients who presented for amniocentesis. Cord blood was obtained from these patients at the time of delivery. Cord blood was also obtained from a group of hepatitis B surface antigen-positive patients for whom no amniocentesis was performed. All samples were analyzed for the presence of hepatitis B surface antigen and hepatitis B deoxyribonucleic acid. RESULTS: A total of 121 hepatitis B surface antigen-positive pregnant women were identified. In the 72 pregnancies in which amniocentesis was not performed, 18% of the cord blood samples were positive for hepatitis B surface antigen and 4% were positive for hepatitis B deoxyribonucleic acid. Of 47 amniocentesis fluid samples, 32% were positive for hepatitis B surface antigen but all were negative for hepatitis B virus deoxyribonucleic acid. Of 30 cord blood samples from patients who underwent an amniocentesis, 27% were positive for hepatitis B surface antigen, but all were negative for hepatitis B virus deoxyribonucleic acid. CONCLUSIONS: This study found that hepatitis B viral deoxyribonucleic acid is rarely present in cord blood and was not identified in amniotic fluid obtained by amniocentesis. This finding suggests that in utero transmission of the virus is rare prior to the onset of labor. These data further confirm the reports in the current literature that the risk of hepatitis B transmission to the fetus during amniocentesis is low. Because hepatitis B surface antigen can exist as an isolated entity devoid of nuclear material, in some cases this protein may be able to traverse the placental and amniotic membrane barrier in a manner similar to other proteins, such as alpha-fetoprotein. Recommendations for genetic amniocentesis in women positive for hepatitis B surface antigen are discussed.

Neonatal outcome when delivery follows a borderline immature lecithin to sphingomyelin ratio.

OBJECTIVE: Occasionally, clinicians are presented with a complicated preterm pregnancy where fetal pulmonary maturity testing might be used to help guide management decisions. However, should delivery be allowed if the lecithin to sphingomyelin ratio (L/S ratio) is not quite mature? The incidence of newborn complications after delivery with L/S ratio values of 1.8 and 1.9 is unknown. The purpose of this study was to evaluate the neonatal morbidity and mortality in patients that delivered with these borderline immature results. STUDY DESIGN: All patients who underwent fetal pulmonary maturity testing were prospectively recorded in log books. An L/S ratio of > or = 2.0 was considered mature. Patients with an L/S ratio of 1.8 or 1.9 were considered "borderline immature." These borderline immature cases were evaluated for the gestational age at amniocentesis, the gestational age at delivery, and neonatal outcome. RESULTS: During the 9-year study period, L/S ratio testing was performed on 2038 patients. Of these, 162 preterm patients (7.9%) had an L/S ratio of 1.8 or 1.9 A total of 63 of these 162 patients delivered < 72 hours after the amniocentesis and met study criteria. The pregnancies ranged from 27 to 36 weeks' gestation. There was a 13% incidence (95% confidence interval (CI) of 4% to 30%) of major neonatal morbidity and a 3% incidence (95% CI of 0% to 17%) of neonatal mortality in the 30 pregnancies with an L/S ratio of 1.8. The incidence of major neonatal morbidity was only 3% (95% CI of 0% to 15%) in the 33 patients with an L/S ratio of 1.9, with no cases of mortality (95% CI of 0% to 9%). CONCLUSION: Based on 95% CIs, the data of this study reveal that the maximum risk for major morbidity is < or = 15%, with a mortality risk of < 10% in a preterm newborn delivered with a 1.9 L/S ratio value. The maximum risk is 30% for major morbidity and 17% for mortality in preterm newborns delivered with a 1.8 L/S ratio. This information may help in the decision-making process of whether to deliver or to observe when faced with a borderline immature L/S ratio result in a complicated preterm pregnancy.

3D simulation of EIT for monitoring impedance variations within the human head.

A preliminary analysis is presented concerning the use of EIT for detecting impedance inhomogeneities within the human brain. The work to date is centred around the monitoring of two distinct impedance variations: those associated with the application of a carotid clamp during surgery and changes caused by the redistribution of blood flow during auditory stimuli. Using the commercially available Ansoft Maxwell package, a 3D finite element model of the human head has been developed to solve the forward problem. The model is hemispherical in shape and comprises regions of brain, cerebrospinal fluid, skull and skin and includes 16 scalp electrodes each of area 1 cm2. Results from simulations using the model suggest that an EIT system, incorporating diametric current excitation, would require a voltage measurement sensitivity of 100-120 dB in order to detect the impedance variations in the above cases.

The effect of transport on the rate of severe intraventricular hemorrhage in very low birth weight infants.

OBJECTIVE: To determine the incidence of grade III or IV intraventricular hemorrhage in very low birth weight (VLBW) infants born at level I hospitals and transported to one tertiary center compared with those delivered at the same level III facility. METHODS: We evaluated all newborns admitted to a large tertiary neonatal intensive care unit from June 1, 1992, through December 31, 1995. All live born infants with birth weights of 500-1200 g and at least 24 weeks' gestation were included. Neonatal transports within 24 hours of delivery from 11 level I facilities were compared with those delivered at the same level III center with respect to grade III and IV intraventricular hemorrhage. Various antenatal and neonatal data were collected. RESULTS: Thirty-seven newborns (11%) experienced grade III or IV intraventricular hemorrhages among 329 who met study criteria. There were 27 cases (9%) in the 285 inborn neonates compared with 10 of 44 outborn cases (23%) (P < .02, 95% confidence interval 0.15, 0.87). The mean gestational age of the neonates with grade III or IV intraventricular hemorrhages was significantly lower in the inborn group, which further emphasizes the finding. No other study factors explained the difference. CONCLUSION: We found a higher risk for grade III or IV intraventricular hemorrhage developing in VLBW infants born at level I hospitals and transported to the tertiary care center compared with those born at the level III facility. This data should be considered when analyzing the potential effects of perinatal deregionalization.

Incidence of intrapartum maternal risk factors for identifying neonates at risk for early-onset group B streptococcal sepsis: A prospective study.

OBJECTIVE: In mid-1996 and early 1997, the Centers for Disease Control and Prevention, The American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics all published guidelines outlining 2 potential strategies for the purpose of preventing neonatal sepsis caused by group B Streptococcus. One of these approaches involves treating pregnant women intrapartum with antibiotics if any of the following risk factors develop: delivery at <37 weeks' gestation, membrane rupture for >/=18 hours' duration, or temperature during labor of >/=38 degrees C. However, to date there have been no population-based studies that have ascertained the percentage of pregnant women eligible to receive intrapartum antibiotic chemoprophylaxis if these risk factors were used. Our objective was to perform a large patient-based study at >1 institution evaluating all deliveries for the presence of maternal risk factors by using the definitions of the current guidelines. STUDY DESIGN: A prospective cohort study was initiated in 1995 at 3 private community hospitals and 1 private referral center. The study population was composed of 5410 consecutively delivered patients from the 4 different hospitals. Every pregnancy was analyzed for gestational age at delivery, duration of membrane rupture, temperature during labor, and use of intrapartum antibiotic chemoprophylaxis. RESULTS: Of the 5410 patients, a total of 455 (8. 4%) were delivered of their neonates before 37 weeks' gestation, 421 (7.8%) had rupture of membranes for at least 18 hours' duration, and 378 (7.0%) had an intrapartum temperature of >/=38 degrees C. Overall, 1071 pregnant women (19.8% of the population studied) had >/=1 of the defined risk factors. CONCLUSIONS: These data suggest that, if the current risk factor strategy is used, 19.8% of the delivering population would potentially be candidates for intrapartum antibiotic chemoprophylaxis.

The capture rate of at-risk term newborns for early-onset group B streptococcal sepsis determined by a risk factor approach.

OBJECTIVE: Currently, the Centers for Disease Control and Prevention, The American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics recommend that health care providers for pregnant women implement 1 of 2 strategies for the potential prevention of early-onset neonatal group B streptococcal sepsis. Both algorithms recommend intrapartum antibiotic chemoprophylaxis for patients delivered of their neonates at <37 weeks' gestation. The basic difference lies in the management of the term pregnancy. One protocol suggests treatment of all patients with term pregnancies with a positive culture for group B Streptococcus obtained at 35 to 37 weeks' gestation. The second approach recommends treatment on the basis of risk factors of membrane rupture of >/=18 hours' duration or intrapartum temperature of >/=38 degrees C. The capture rate of at-risk neonates determined by the risk factor strategy is quoted as being approximately 70%; however, the basis for this percentage was from studies that used slightly different definitions than the current guidelines and never separated the term from the preterm newborn. Our objective was to prospectively collect every case of blood culture-proven early-onset neonatal group B streptococcal sepsis and determine whether risk factors, as currently defined, were present that might have warranted maternal intrapartum antibiotic chemoprophylaxis. STUDY DESIGN: A prospective study was initiated on July 1, 1987, and completed on December 31, 1996. Every patient that was delivered of a neonate in whom early-onset group B streptococcal sepsis developed was analyzed in detail for possible intrapartum risk factors. RESULTS: A total of 49 cases of early-onset group B streptococcal sepsis occurred in 46,959 deliveries. Of these 49 newborns, 9 (18%) were delivered at <37 weeks' gestation. The remaining 40 newborns were delivered at term, and only 12 (30%) were delivered with an intrapartum risk factor of either membrane rupture of >/=18 hours' duration or temperature of >/=38 degrees C or both. CONCLUSIONS: On the basis of the data from this study and the current literature, the risk factor approach with the current guideline recommendations would capture <50% of the term newborns in whom sepsis develops.

Is tocolysis safe in the management of third-trimester bleeding?

OBJECTIVE: Expectant management is among the current treatment options for pregnancies complicated by third-trimester bleeding at <36 weeks' gestation. The use of tocolytic agents to stop associated contractions is still somewhat controversial, however, and the number of cases reported to date is small. The purpose of our study was to find a large number of cases of preterm third-trimester bleeding that was treated with tocolytic agents and evaluate them for any evidence of potential harm related to the use of these agents. STUDY DESIGN: Every case of third-trimester bleeding for a 6-year period was obtained from a perinatal database that was created as patients were hospitalized. Only cases of patients with onset of bleeding between 23 and 36 weeks' gestation were analyzed. Data collected included the gestational age at the time of first bleeding, the gestational age at delivery, whether tocolytic agents were used, the need for transfusion, maternal morbidity, and neonatal outcome. RESULTS: A total of 236 cases, consisting of 131 cases of abruptio placentae and 105 cases of placenta previa, met the study criteria. In the abruptio placentae group 95 women (73%) were treated with tocolytic agents. In this group the mean gestational age at the time of first bleeding was 28.9 weeks, the mean time from bleeding until delivery was 18.9 days, the median time from bleeding until delivery was 7 days, and the neonatal mortality rate was 51 deaths/1000 live births. In the placenta previa group 76 patients (72%) were treated with tocolytic agents. In this group the mean gestational age at first bleeding was 29.5 weeks, the mean time from bleeding until delivery was 29.3 days, the median time from bleeding until delivery was 22 days, and the neonatal mortality rate was 39 deaths/1000 live births. In both groups the need for transfusion and the incidence of fetal distress were not increased by the use of tocolytic agents. Among the 171 combined patients who underwent tocolysis, no maternal morbidity related to the tocolytic agents was found and no stillbirths occurred after admission. The neonatal deaths were all related to complications of prematurity. CONCLUSIONS: This is the largest series to date evaluating the use of tocolytic agents in preterm patients with third-trimester bleeding. From these data there does not appear to be any increased morbidity or mortality associated with tocolytic agent use in a controlled tertiary setting. A prospective randomized trial would be necessary to determine whether tocolytic use carries any benefits.

Meconium has no lecithin or sphingomyelin but affects the lecithin/sphingomyelin ratio.

OBJECTIVE: Although a few studies have evaluated the effect of meconium on the lecithin/sphingomyelin ratio for testing of fetal lung maturity, to date these studies have assessed only the lecithin-sphingomyelin ratio of amniotic fluid contaminated with meconium. The purpose of this study was (1) to determine whether meconium by itself has a lecithin/sphingomyelin ratio and, if so, (2) to determine whether the lecithin/sphingomyelin ratio is constant. STUDY DESIGN: A lecithin/sphingomyelin ratio was obtained by standard thin-layer chromatography on the first meconium stool of 20 neonates between 31 weeks and term. A quantitative assay was then performed on a sample from each gestational age (7 samples ranging from 31 weeks to term) to confirm the presence of lecithin and sphingomyelin. RESULTS: The 20 samples had atypical thin-layer chromatographic migratory patterns in the zones for lecithin and sphingomyelin. The presumed lecithin/sphingomyelin ratios ranged from 1.1 to 3.6, with no correlation with gestational age. However, the quantitative assay did not detect the presence of lecithin or sphingomyelin in any of the analyzed samples. CONCLUSIONS: Meconium does not appear to contain lecithin or sphingomyelin but has an unidentified moiety whose migratory pattern, as shown by qualitative standard thin-layer chromatography, is similar to that of lecithin with sphingomyelin. Therefore the presence of meconium in amniotic fluid may falsely raise or lower the lecithin/sphingomyelin ratio and confuse fetal lung maturity interpretations.

A "bloodless cesarean section" and perinatal transmission of the human immunodeficiency virus.

OBJECTIVE: Perinatal transmission of the human immunodeficiency virus is the main pathway for children to become infected with this virus; however, the relative contribution and timing of this transmission, whether transplacental or by exposure through the birth process, have not yet been elucidated. An obvious question is whether the mode of delivery has an impact on this transmission rate. However, a routine cesarean section will primarily diminish the duration of exposure of maternal bodily fluids to the neonate but does not prevent the baby from being exposed to maternal blood coming from the uterine incision. The purpose of this study was to determine whether the rate of perinatal transmission of human immunodeficiency virus could be significantly lowered by delivering the baby with minimal to no exposure to maternal blood or bodily fluids by the use of a surgical technique termed a "bloodless cesarean section." STUDY DESIGN: We performed a prospective cohort study in a group of pregnant women infected with human immunodeficiency virus and evaluated the rate of transmission of this virus to the neonate on the basis of the mode of delivery. One group of patients was delivered by means of a "bloodless cesarean section," in which the baby was delivered and not exposed to any maternal blood or bodily fluid. The control group gave birth either by vaginal delivery or by routine cesarean section. All of the newborns were followed up for a minimum of 15 months or until negative findings were confirmed. Multiple antenatal, intrapartum, and postdelivery variables were collected and analyzed. RESULTS: A total of 108 patients were included in this study and 14 neonates became infected with human immunodeficiency virus (13%). Three of 53 infants delivered by a bloodless cesarean section (5.7%) became infected compared with 11 of 55 control patients (20.0%). This was significant at P = .02 and represented an absolute difference in percentage between the 2 groups of 14.3%, which corresponds to a 71.5% relative reduction in transmission risk (z = 2.27, P = .012). Since the use of zidovudine greatly influences the perinatal transmission rate of human immunodeficiency virus, the study data were reanalyzed with the exclusion of patients who used antenatal or intrapartum zidovudine. Two of 32 infants in the bloodless cesarean section group (6.3%) were infected compared with 9 of 38 in the control group (23.7%). This was significant at P = .04 and revealed an absolute difference in percentage of 17.4%, which corresponds to a 73.4% relative reduction in transmission risk (z = 2.15, P = .016). There was no difference in the transmission rate between the bloodless cesarean section patients who did not use zidovudine (2/32, 6.3%) and the patients who did use zidovudine from the entire study population (3/38, 7.9%). CONCLUSION: In the absence of zidovudine usage, these data show that 70% to 75% of the perinatal transmission of human immunodeficiency virus to a newborn occurs from exposure to maternal blood and bodily fluids at the time of birth. This information is important for patients unable to take zidovudine or other antiretroviral agents, but more important, it introduces the concept of other treatment options for the future.

Potential consequences of widespread antepartal use of ampicillin.

OBJECTIVE: Recommendations for the use of antenatal antibiotics in obstetrics have increased in the past few years, especially for prophylaxis against group B streptococci, for prolongation of the latency time in patients with preterm premature rupture of the membranes, and as an adjuvant treatment in preterm labor. Our objective was to determine whether the use of antenatal ampicillin affects the incidence of and resistance of early-onset neonatal sepsis with organisms other than group B streptococci. STUDY DESIGN: A prospective cohort study was performed between January 1, 1991, and December 31, 1996. Every case of blood culture-proven neonatal sepsis was prospectively surveyed. The type of bacteria isolated, drug resistance, antenatal antibiotic use and treatment indication, gestational age at delivery, and other antenatal and outcome variables were gathered. Early-onset neonatal sepsis was defined as disease onset within 7 days after birth. RESULTS: A total of 42 cases of early-onset neonatal sepsis among 29,897 neonates delivered were found during the 6-year period. Of these, 15 cases were due to group B streptococci and 27 were the result of non-group B streptococcal organisms (21 gram-negative rods and 6 gram-positive cocci). Among the 27 non-group B streptococcal cases, 15 mothers had received antenatal ampicillin and 13 of the 15 bacterial isolates from these neonates (87%) were resistant to ampicillin, versus only 2 ampicillin-resistant isolates (17%) among the 12 cases in which no antenatal antibiotics were administered (P = .0004). Of the 15 mothers who were treated with ampicillin, 13 received more than 1 dose. In evaluating each year of the study, the overall administration of antibiotics to pregnant women in the antenatal period increased from <10% in 1991 to 16.9% in 1996. The incidence of early-onset neonatal sepsis with group B streptococci decreased during this time, whereas the incidence of early-onset sepsis with non-group B streptococcal organisms, especially Escherichia coli, increased. CONCLUSIONS: The increased administration of antenatal ampicillin to pregnant women may be responsible for the increased incidence of early-onset neonatal sepsis with non-group B streptococcal organisms that are resistant to ampicillin. At this time penicillin G, rather than ampicillin, is therefore recommended for prophylaxis against group B streptococci. In addition, future studies are needed to determine whether alternate approaches, such as immunotherapy or vaginal washing, could be of benefit.

Is fluorescence polarization reliable and cost efficient in a fetal lung maturity cascade?

OBJECTIVE: The objective of the study was to compare the accuracy of the TDxFLM test (Abbott Laboratories) with the fetal lung maturity cascade (shake, foam stability index, lecithin/sphingomyelin tests) and to determine whether the TDxFLM test could increase the efficiency and reduce the cost without decreasing the reliability of a cascade. STUDY DESIGN: A prospective, single-blinded study was conducted. Uncontaminated amniotic fluid obtained by transabdominal amniocentesis for fetal lung maturity assessment was evaluated with use of the fetal lung maturity cascade and the TDxFLM test. At study completion the results of the TDxFLM test were compared with those of the maturity cascade with regard to hyaline membrane disease, which was defined by strict clinical and radiographic parameters. A power analysis was performed requiring a sample size of 100 infants delivered within 72 hours of amniocentesis with use of the 95% confidence interval. RESULTS: A total of 115 cases had a full maturity cascade performed, of which 40 (35%) had a positive shake or foam stability index and 75 cases required progression to a lecithin/sphingomyelin ratio because of negative results. The TDxFLM test result was > or = 70 mg/gm in 42 (37%) of these 115. One hundred eight newborns were delivered within 72 hours of the amniocentesis; 65% (71) of these were between 30 and 37 weeks of estimated gestational age. There were 7 cases of hyaline membrane disease in the 108 newborns. Of these 108, 87 had a mature original cascade versus 85 mature tests with use of a proposed TDxFLM test-lecithin/sphingomyelin ratio cascade with one case of respiratory distress syndrome and hyaline membrane disease. The sensitivity, specificity, and positive and negative predictive values for the original cascade were 86%, 84%, 27%, and 99%, respectively; for the proposed TDxFLM test-lecithin/sphingomyelin ratio cascade the values were 86%, 83%, 26%, and 99%, respectively. The TDxFLM test-lecithin/sphingomyelin ratio cascade would have resulted in a cost reduction of 24% with no significant delay in turnaround time. CONCLUSION: The TDxFLM test appears to be a reliable and accurate assessment of fetal lung maturity. Furthermore, by replacing the shake and foam stability index portion of the cascade with the TDxFLM test, a cost savings of 24% would occur without a decrease in safety. These results also reveal that it could enhance patient care and be cost efficient for institutions not currently doing fetal pulmonary maturity testing to undertake use of the TDxFLM test and to only send out specimens for a lecithin/sphingomyelin ratio that have an initial immature TDxFLM test result (< 70 mg/gm). Likewise, institutions currently only performing a lecithin/sphingomyelin ratio may consider a TDxFLM test-lecithin sphingomyelin ratio cascade. Although direct costs would increase, they would be counterbalanced by a significant reduction in laboratory technician time.