Management of late-onset fetal growth restriction: pragmatic approach.

OBJECTIVES: There is limited prospective evidence to guide the management of late-onset fetal growth restriction (FGR) and its differentiation from small-for-gestational age. The aim of this study was to assess prospectively a novel protocol in which ultrasound criteria were used to classify women with suspected late FGR into two groups: those at low risk, who were managed expectantly until the anticipated date of delivery, and those at high risk, who were delivered soon after 37 weeks of gestation. We also compared the outcome of this prospective cohort with that of a historical cohort of women presenting similarly with suspected late FGR, in order to evaluate the impact of the new protocol. METHODS: This was a prospective study of women with a non-anomalous singleton pregnancy at ≥ 32 weeks' gestation attending a tertiary hospital in London, UK, between February 2018 and September 2019, with estimated fetal weight (EFW) ≤ 10th centile, or EFW > 10th centile in addition to a decrease in fetal abdominal circumference of ≥ 50 centiles compared with a previous scan, umbilical artery Doppler pulsatility index > 95th centile or cerebroplacental ratio < 5th centile. Women were classified as low or high risk based on ultrasound and Doppler criteria. Women in the low-risk group were delivered by 41 weeks of gestation, unless they subsequently met high-risk criteria, whereas women in the high-risk group (EFW < 3rd centile, umbilical artery Doppler pulsatility index > 95th centile or EFW between 3rd and 10th centiles (inclusive) with abdominal circumference drop or abnormal Dopplers) were delivered at or soon after 37 weeks. The primary outcome was adverse neonatal outcome and included hypothermia, hypoglycemia, neonatal unit admission, jaundice requiring treatment, suspected infection, feeding difficulties, 1-min Apgar score < 7, hospital readmission and any severe adverse neonatal outcome (perinatal death, resuscitation using inotropes or mechanical ventilation, 5-min Apgar score < 7, metabolic acidosis, sepsis, and cerebral, cardiac or respiratory morbidity). Secondary outcomes were adverse maternal outcome (operative delivery for abnormal fetal heart rate) and severe adverse neonatal outcome. Women managed according to the new protocol were compared with a historical cohort of 323 women delivered prior to the implementation of the new protocol, for whom management was guided by individual clinician expertise. RESULTS: Over 18 months, 321 women were recruited to the prospective cohort, of whom 156 were classified as low risk and 165 were high risk. Adverse neonatal outcome was significantly less common in the low-risk compared with the high-risk group (45% vs 58%; adjusted odds ratio (aOR), 0.6 (95% CI, 0.4-0.9); P = 0.022). There was no significant difference in the rate of adverse maternal outcome (18% vs 24%; aOR, 0.7 (95% CI, 0.4-1.2); P = 0.142) or severe adverse neonatal outcome (3.8% vs 8.5%; aOR, 0.5 (95% CI, 0.2-1.3); P = 0.153) between the low- and high-risk groups. Compared with women in the historical cohort classified retrospectively as low risk, low-risk women managed under the new protocol had a lower rate of adverse neonatal outcome (45% vs 58%; aOR, 0.6 (95% CI, 0.4-0.9); P = 0.026). CONCLUSIONS: Appropriate risk stratification to guide management of late FGR was associated with a reduced rate of adverse neonatal outcome in low-risk pregnancies. In clinical practice, a policy of expectantly managing women with a low-risk late-onset FGR pregnancy at term could improve neonatal and long-term development. Randomized controlled trials are needed to assess the effect of an evidence-based conservative management protocol for late FGR on perinatal morbidity and mortality and long-term neurodevelopment. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Improving antenatal detection of small-for-gestational-age fetus: economic evaluation of Growth Assessment Protocol.

OBJECTIVE: To determine whether the Growth Assessment Protocol (GAP), as implemented in the DESiGN trial, is cost-effective in terms of antenatal detection of small-for-gestational-age (SGA) neonate, when compared with standard care. METHODS: This was an incremental cost-effectiveness analysis undertaken from the perspective of a UK National Health Service hospital provider. Thirteen maternity units from England, UK, were recruited to the DESiGN (DEtection of Small for GestatioNal age fetus) trial, a cluster randomized controlled trial. Singleton, non-anomalous pregnancies which delivered after 24 + 0 gestational weeks between November 2015 and February 2019 were analyzed. Probabilistic decision modeling using clinical trial data was undertaken. The main outcomes of the study were the expected incremental cost, the additional number of SGA neonates identified antenatally and the incremental cost-effectiveness ratio (ICER) (cost per additional SGA neonate identified) of implementing GAP. Secondary analysis focused on the ICER per infant quality-adjusted life year (QALY) gained. RESULTS: The expected incremental cost (including hospital care and implementation costs) of GAP over standard care was £34 559 per 1000 births, with a 68% probability that implementation of GAP would be associated with increased costs to sustain program delivery. GAP identified an additional 1.77 SGA neonates per 1000 births (55% probability of it being more clinically effective). The ICER for GAP was £19 525 per additional SGA neonate identified, with a 44% probability that GAP would both increase cost and identify more SGA neonates compared with standard care. The probability of GAP being the dominant clinical strategy was low (11%). The expected incremental cost per infant QALY gained ranged from £68 242 to £545 940, depending on assumptions regarding the QALY value of detection of SGA. CONCLUSION: The economic case for replacing standard care with GAP is weak based on the analysis reported in our study. However, this conclusion should be viewed taking into account that cost-effectiveness analyses are always limited by the assumptions made. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Achieving orphan designation for placental insufficiency: annual incidence estimations in Europe.

OBJECTIVE: To determine whether a novel therapy for placental insufficiency could achieve orphan drug status by estimating the annual incidence of placental insufficiency, defined as an estimated fetal weight below the 10th centile in the presence of abnormal umbilical artery Doppler velocimetry, per 10 000 European Union (EU) population as part of an application for European Medicines Agency (EMA) orphan designation. DESIGN: Incidence estimation based on literature review and published national and EU statistics. SETTING AND POPULATION: European Union. METHODS: Data were drawn from published literature, including national and international guidelines, international consensus statements, cohort studies and randomised controlled trials, and published national and EU statistics, including birth rates and stillbirth rates. Rare disease databases were also searched. RESULTS: The proportion of affected pregnancies was estimated as 3.17% (95% CI 2.93-3.43%), using a weighted average of the results from two cohort studies. Using birth rates from 2012 and adjusting for a pregnancy loss rate of 1/100 gave an estimated annual incidence of 3.33 per 10 000 EU population (95% CI 3.07-3.60 per 10 000 EU population). This fell below the EMA threshold of 5 per 10 000 EU population. CONCLUSIONS: Maternal vascular endothelial growth factor gene therapy for placental insufficiency was granted EMA orphan status in 2015 after we demonstrated that it is a rare, life-threatening or chronically debilitating and currently untreatable disease. Developers of other potential obstetric therapies should consider applying for orphan designation, which provides financial and regulatory benefits. TWEETABLE ABSTRACT: Placental insufficiency meets the European Medicines Agency requirements for orphan disease designation.

Perinatal and long-term effects of maternal uterine artery adenoviral VEGF-A165 gene therapy in the growth-restricted guinea pig fetus.

Uterine artery application of adenoviral vascular endothelial growth factor A165 (Ad.VEGF-A165) gene therapy increases uterine blood flow and fetal growth in experimental animals with fetal growth restriction (FGR). Whether Ad.VEGF-A165 reduces lifelong cardiovascular disease risk imposed by FGR remains unknown. Here, pregnant guinea pigs fed 70% normal food intake to induce FGR received Ad.VEGF-A165 (1×1010 viral particles, n = 15) or vehicle ( n = 10), delivered to the external surface of the uterine arteries, in midpregnancy. Ad libitum-fed controls received vehicle only ( n = 14). Litter size, gestation length, and perinatal mortality were similar in control, untreated FGR, and FGR+Ad.VEGF-A165 animals. When compared with controls, birth weight was lower in male but higher in female pups following maternal nutrient restriction, whereas both male and female FGR+Ad.VEGF-A165 pups were heavier than untreated FGR pups ( P < 0.05, ANOVA). Postnatal weight gain was 10-20% greater in female FGR+Ad.VEGF-A165 than in untreated FGR pups, depending on age, although neither group differed from controls. Maternal nutrient restriction reduced heart weight in adult female offspring irrespective of Ad.VEGF-A165 treatment but did not alter ventricular wall thickness. In males, postnatal weight gain and heart morphology were not affected by maternal treatment. Neither systolic, diastolic, mean arterial pressure, adrenal weight, nor basal or challenged plasma cortisol were affected by maternal undernutrition or Ad.VEGF-A165 in either sex. Therefore, increased fetal growth conferred by maternal uterine artery Ad.VEGF-A165 is sustained postnatally in FGR female guinea pigs. In this study, we did not find evidence for an effect of maternal nutrient restriction or Ad.VEGF-A165 therapy on adult offspring blood pressure.

Total uterine artery blood volume flow rate in nulliparous women is associated with birth weight and gestational age at delivery.

OBJECTIVES: To investigate the relationship between total uterine artery blood volume flow rate (TVFR) and birth weight and gestational age at delivery, and to establish normal ranges of TVFR throughout pregnancy. METHODS: This was a prospective cohort study of 334 nulliparous women booking antenatal care at University College London Hospital between August 2008 and September 2009. Women underwent a transabdominal ultrasound examination of uterine arteries for measurement of TVFR at 12, 20 and 24 weeks' gestation. Pregnancy outcomes were recorded and linear regression was used to study the relationship between TVFR and gestational age at delivery and birth weight. RESULTS: A total of 551 ultrasound scans were performed. There was a significant, positive correlation between TVFR at 11-13 weeks (TVFR1) and at 22-26 weeks (TVFR3) and birth weight. For every 100-mL/min increase in TVFR1 and TVFR3, there was an increase in birth weight of 45 g and 27 g, respectively. There was also a positive association between TVFR1 and gestational age at delivery, with a 1.4-day increase in gestational age for every 100-mL/min increase of TVFR1. CONCLUSION: Ultrasound measurement of TVFR in the first trimester is significantly associated with both birth weight and gestational age at delivery. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Is the increased risk of preterm birth following excision for cervical intraepithelial neoplasia restricted to the first birth post treatment?

OBJECTIVE: To explore whether the increased risk of preterm birth following treatment for cervical disease is limited to the first birth following colposcopy. DESIGN: Nested case-control study. SETTING: Twelve NHS hospitals in England. POPULATION: All nonmultiple births from women selected as cases or controls from a cohort of women with both colposcopy and a hospital birth. Cases had a preterm (20-36 weeks of gestation) birth. Controls had a term birth (38-42 weeks) and no preterm. METHODS: Obstetric, colposcopy and pathology details were obtained. MAIN OUTCOME MEASURES: Adjusted odds ratio of preterm birth in first and second or subsequent births following treatment for cervical disease. RESULTS: A total of 2798 births (1021 preterm) from 2001 women were included in the analysis. The risk of preterm birth increased with increasing depth of treatment among first births post treatment [trend per category increase in depth, categories <10 mm, 10-14 mm, 15-19 mm, ≥20 mm: odds ratio (OR) 1.23, 95% confidence interval (95% CI) 1.12-1.36, P < 0.001] and among second and subsequent births post treatment (trend OR 1.34, 95% CI 1.15-1.56, P < 0.001). No trend was observed among births before colposcopy (OR 0.98, 95% CI 0.83-1.16, P = 0.855). The absolute risk of a preterm birth following deep treatments (≥15 mm) was 6.5% among births before colposcopy, 18.9% among first births and 17.2% among second and subsequent births post treatment. Risk of preterm birth (once depth was accounted for) did not differ when comparing first births post colposcopy with second and subsequent births post colposcopy (adjusted OR 1.15, 95% CI 0.89-1.49). CONCLUSIONS: The increased risk of preterm birth following treatment for cervical disease is not restricted to the first birth post colposcopy; it remains for second and subsequent births. These results suggest that once a woman has a deep treatment she remains at higher risk of a preterm birth throughout her reproductive life.

Maternal Uterine Artery Adenoviral Vascular Endothelial Growth Factor (Ad.VEGF-A165) Gene Therapy Normalises Fetal Brain Growth and Microglial Activation in Nutrient Restricted Pregnant Guinea Pigs.

Fetal growth restriction (FGR) is associated with uteroplacental insufficiency, and neurodevelopmental and structural brain deficits in the infant. It is currently untreatable. We hypothesised that treating the maternal uterine artery with vascular endothelial growth factor adenoviral gene therapy (Ad.VEGF-A165) normalises offspring brain weight and prevents brain injury in a guinea pig model of FGR. Pregnant guinea pigs were fed a restricted diet before and after conception and received Ad.VEGF-A165 (1 × 1010 viral particles, n = 18) or vehicle (n = 18), delivered to the external surface of the uterine arteries, in mid-pregnancy. Pregnant, ad libitum-fed controls received vehicle only (n = 10). Offspring brain weight and histological indices of brain injury were assessed at term and 5-months postnatally. At term, maternal nutrient restriction reduced fetal brain weight and increased microglial ramification in all brain regions but did not alter indices of cell death, astrogliosis or myelination. Ad.VEGF-A165 increased brain weight and reduced microglial ramification in fetuses of nutrient restricted dams. In adult offspring, maternal nutrient restriction did not alter brain weight or markers of brain injury, whilst Ad.VEGF-A165 increased microglial ramification and astrogliosis in the hippocampus and thalamus, respectively. Ad.VEGF-A165 did not affect cell death or myelination in the fetal or offspring brain. Ad.VEGF-A165 normalises brain growth and markers of brain injury in guinea pig fetuses exposed to maternal nutrient restriction and may be a potential intervention to improve childhood neurodevelopmental outcomes in pregnancies complicated by FGR.

Long-term increase in uterine blood flow is achieved by local overexpression of VEGF-A(165) in the uterine arteries of pregnant sheep.

Increasing uterine artery blood flow (UABF) may benefit fetal growth restriction where impaired uteroplacental perfusion prevails. Based on previous short-term results, we examined the long-term effects of adenovirus vector-mediated overexpression of vascular endothelial growth factor-A(165) (VEGF-A(165)) in the uterine artery (UtA). Transit-time flow probes were implanted around both UtAs of mid-gestation pregnant sheep (n=11) to measure UABF. A carotid artery catheter was inserted to measure maternal or fetal hemodynamics. Baseline UABF was measured over 3 days, before injection of adenovirus vector (5 × 10(11) particles) encoding the VEGF-A(165) gene (Ad.VEGF-A(165)) into one UtA and a reporter ß-galactosidase gene (Ad.LacZ) contralaterally. UABF was then measured daily until term. At 4 weeks post injection, the increase in UABF was significantly higher in Ad.VEGF-A(165) compared with Ad.LacZ-transduced UtAs (36.53% vs 20.08%, P=0.02). There was no significant effect on maternal and fetal blood pressure. Organ bath studies showed significantly lesser vasoconstriction (E(max) 154.1 vs 184.7, P<0.001), whereas immunohistochemistry demonstrated a significantly increased number of adventitial blood vessels (140 vs 91, n=26, P<0.05) following Ad.VEGF-A(165) transduction. Local overexpression of VEGF-A(165) in the UtAs of pregnant mid-gestation sheep leads to a sustained long-term increase in UABF, which may be explained by neovascularization and altered vascular reactivity.

Uterine artery Doppler and adverse pregnancy outcome in women with extreme levels of fetoplacental proteins used for Down syndrome screening.

OBJECTIVE: To evaluate the use of second-trimester uterine artery (UtA) Doppler to predict adverse pregnancy outcome in women with extreme levels of fetoplacental proteins used for Down syndrome screening. METHODS: At a single institution, women screened for Down syndrome were offered second-trimester UtA Doppler examination if they had one of the following on analysis of maternal serum: pregnancy-associated plasma protein-A ≤ 0.28 multiples of the median (MoM) (1% of screened population), inhibin ≥ 3.0 MoM (2%), human chorionic gonadotropin ≥ 4.0 MoM (2%), alpha-fetoprotein (AFP) ≥ 2.5 MoM (2%), estriol ≤ 0.5 MoM (1%). Abnormal UtA Doppler was defined as bilateral or unilateral notching or mean pulsatility index ≥ 1.45. RESULTS: Of 240 women studied, 92 (38.3%) had an adverse pregnancy outcome: small for gestational age (either < 10(th) customized centile (SGA(10) ) or < 5(th) customized centile (SGA(5) )), low birth weight (LBW, < 2.5 kg), preterm delivery (< 37 + 0 weeks of gestation), fetal loss (late miscarriage or stillbirth), placental abruption and gestational hypertension. Of 167 women screened with all five hormones, those with two or more extreme levels (n = 18, 10.8%) were significantly at risk of adverse pregnancy outcome compared with those with only one marker (61.1% vs. 35.6%, P = 0.04). UtA Doppler was abnormal in 20% (32 of 159 women screened) and increased the risk of adverse pregnancy outcome (RR 2.5, 65.6% vs. 26.0%, P < 0.001). SGA(10) , SGA(5) and LBW were significantly more common in women with abnormal UtA Doppler (RR 2.98, 56.2% vs. 18.9%, P < 0.001, RR 4.6, 43.7% vs. 9.4%, P < 0.001 and RR 4.4, 31.2% vs. 7.1%, P < 0.001, respectively). Women with normal Doppler examination still had a 26% risk of adverse pregnancy outcome. CONCLUSIONS: In women with extreme levels of feto-placental proteins used for Down syndrome screening, an abnormal second-trimester UtA Doppler examination confers a high risk of adverse pregnancy outcome and SGA in particular, but a normal examination does not rule out an adverse pregnancy outcome.

Local delivery of VEGF adenovirus to the uterine artery increases vasorelaxation and uterine blood flow in the pregnant sheep.

Impaired materno-placental perfusion causes two important obstetric complications, fetal growth restriction and preeclampsia. This study investigated whether adenoviral vector-mediated overexpression of vascular endothelial growth factor (VEGF) in the uterine arteries (UtAs) increases uterine artery blood flow (UBF). First-generation adenovirus vectors (5 x 10(11) particles) containing the VEGF gene (Ad.VEGF-A or -D) or the beta-galactosidase reporter gene (Ad.lacZ) were injected into the UtAs of pregnant sheep (n=6) at 88-102 days of gestation (term=145 days). UBF was measured using Doppler sonography before, and 4-7 days after injection. Mean UBF increased significantly from 233+/-156 (s.d.) ml min(-1) to 753+/-415 ml min(-1) following Ad.VEGF-A injection (P=0.005, n=5); Ad.lacZ infection had no significant effect. Organ bath experiments on uterine arterial sections 4-7 days after injection showed that, compared with Ad.lacZ vessels, Ad.VEGF-A-transduced vessels had a reduced contractile response to phenylephrine (E max 148+/-10.9 vs E max 228.2+/-27.5, P<0.05) but increased relaxation with bradykinin (pD2 (-log EC50) values 9.11+/-0.01 vs 8.65+/-0.11, P<0.05). Injection of Ad.VEGF-A into the UtAs increases UBF by enhancing vasodilatation. This may provide the basis for therapy in pregnancies complicated by uteroplacental insufficiency.

Audit of the peri-delivery use of unfractionated heparin in women on therapeutic low-molecular weight heparin.

There is no evidence-based approach for the optimal management of peri-delivery anticoagulation in women receiving therapeutic dose of low-molecular weight heparin (LMWH) during pregnancy. Nevertheless, the maintenance of anticoagulation for the maximal period peri-delivery appears appropriate in women considered to be at high risk of venous or arterial thromboembolism. We developed a regimen based on fixed thromboprophylactic dose of unfractionated heparin (UFH) peri-delivery and undertook an audit to evaluate the use and feasibility of this approach and any adverse events. Fixed intravenous thromboprophylactic dose of UFH (15,000 units/24 h) was commenced on the evening prior to a planned delivery [induction of labour or elective caesarean section (CS)], stopped 4 h predelivery and restarted 2-6 h postdelivery. Compliance was good with 32/38 consecutive deliveries managed according to the regimen. There were no cases of postpartum haemorrhage and no thrombosis associated with these 32 deliveries. Twenty-one patients were delivered by CS (11 elective) and eight patients received epidural/spinal anaesthesia without complication. In conclusion, the fixed thromboprophylactic dose UFH regimen provided maintenance of anticoagulation except for a matter of hours without excessive bleeding risk (conducive to neuroaxial anaesthesia) and was simple, flexible and acceptable to staff and patients.

Association of isolated short femur in the mid-trimester fetus with perinatal outcome.

OBJECTIVES: To evaluate the prevalence of fetal isolated short femur in a cohort of women screened for Down syndrome by the integrated test, and to compare the outcome of fetuses with isolated short femur in the mid-trimester with that of fetuses with normal femur length (controls). METHODS: This was a retrospective cohort study of 1262 women booked for antenatal care and delivery at University College London Hospital. All women had integrated testing in the late first and early second trimesters and a detailed anomaly scan in the mid-trimester. All scan reports, screening results and neonatal data were analyzed statistically. RESULTS: The fetal femur was short (< 5(th) percentile) in 5.1% of patients and 4.7% had isolated short femur. In pregnancies with isolated short femur, the birth weight was significantly lower and there were higher rates of small-for-gestational age (SGA) and low birth weight (LBW) infants, compared with controls (P < 0.01). The odds ratios for SGA and LBW in pregnancies with isolated short femur were 3.0 (95% CI, 1.5-5.9) and 2.60 (95% CI, 1.1-6.2), respectively. Isolated short femur was associated significantly with low levels of pregnancy-associated plasma protein-A (P = 0.001). CONCLUSIONS: Isolated short femur in the mid-trimester fetus is associated with fetal growth restriction and SGA. In the context of normal Down syndrome screening and a normal anomaly scan, this marker should be regarded as a predictor for SGA, and fetal growth should be monitored during these pregnancies.

An innovative virtual reality training tool for orthognathic surgery.

Virtual reality (VR) surgery using Oculus Rift and Leap Motion devices is a multi-sensory, holistic surgical training experience. A multimedia combination including 360° videos, three-dimensional interaction, and stereoscopic videos in VR has been developed to enable trainees to experience a realistic surgery environment. The innovation allows trainees to interact with the individual components of the maxillofacial anatomy and apply surgical instruments while watching close-up stereoscopic three-dimensional videos of the surgery. In this study, a novel training tool for Le Fort I osteotomy based on immersive virtual reality (iVR) was developed and validated. Seven consultant oral and maxillofacial surgeons evaluated the application for face and content validity. Using a structured assessment process, the surgeons commented on the content of the developed training tool, its realism and usability, and the applicability of VR surgery for orthognathic surgical training. The results confirmed the clinical applicability of VR for delivering training in orthognathic surgery. Modifications were suggested to improve the user experience and interactions with the surgical instruments. This training tool is ready for testing with surgical trainees.

Clinically applicable procedure for gene delivery to fetal gut by ultrasound-guided gastric injection: toward prenatal prevention of early-onset intestinal diseases.

Targeting gene therapy vectors to the fetal intestinal tract could provide a novel means toward prevention of the early postnatal intestinal pathology of cystic fibrosis and other conditions, such as congenital enteropathy, that cause intestinal failure. Among these conditions, cystic fibrosis is by far the most common lethal genetic disease. It is caused by a functional absence or deficiency of the cystic fibrosis transmembrane conductance regulator and manifests in the gut as meconium ileus. Prenatal treatment of genetic disease may avoid early-onset tissue damage and immune sensitization, and may target cells that are less accessible in the adult. We investigated gene transfer to the fetal gut, using a minimally invasive injection technique. First-generation replication-deficient adenoviral vectors encoding the beta-galactosidase gene and transduction-enhancing agents were injected into the stomach of early-gestation fetal sheep (n = 8, 60 days of gestation; term, 145 days) under ultrasound guidance. Reporter gene expression was observed 2 days after injection in the villi of the gastrointestinal epithelia after 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining and beta-galactosidase immunohistochemistry of fetal tissues. Expression of beta-galactosidase, as measured by enzyme-linked immunosorbent assay, was enhanced after pretreatment of the fetal gut with sodium caprate, which opens tight junctions, and after adenovirus complexation with DEAE-dextran, which confers a positive charge to the virus. Instillation of the fluorocarbon perflubron after virus delivery resulted in tissue transduction from the fetal stomach to the colon. Using a clinically relevant technique, we have demonstrated widespread gene transfer to the fetal gastrointestinal epithelia.

Acute fetal hypoxia: the modulating effect of infection.

The fetal brain is protected from the effects of acute hypoxia by a range of haemodynamic and metabolic compensations. Hypoxia alone is therefore an unusual cause of perinatal brain injury in either preterm or term infants. More recently, materno-fetal infection has been implicated as a causative factor in cases of cerebral palsy associated with preterm and term birth. This paper explores the concept that exposure to infection, and in particular pro-inflammatory cytokines, may reduce the threshold at which hypoxia becomes neurotoxic, so making the brain much more vulnerable to even mild hypoxic insults. The hypothesis is supported by an increasing body of evidence from animal studies that also demonstrate the importance of duration between exposure to infection and subsequent hypoxia. There are a number of clinical and research implications that centre around the role of antibiotics, mode and timing of delivery, maternal cooling during labour and the role of immune-modulating drugs.

The role of different strain backgrounds in bacterial endotoxin-mediated sensitization to neonatal hypoxic-ischemic brain damage.

Genetic background is known to influence the outcome in mouse models of human disease, and previous experimental studies have shown strain variability in the neonatal mouse model of hypoxia-ischemia. To further map out this variability, we compared five commonly used mouse strains: C57BL/6, 129SVJ, BALB/c, CD1 and FVB in a pure hypoxic-ischemic setup and following pre-sensitization with lipopolysaccharide (LPS). Postnatal day 7 pups were subjected to unilateral carotid artery occlusion followed by continuous 30 min 8% oxygen exposure at 36 °C. Twelve hours prior, a third of the pups received a single intraperitoneal LPS (0.6 µg/g) or a saline (vehicle) administration, respectively; a further third underwent hypoxia-ischemia alone without preceding injection. Both C57BL/6 and 129SVJ strains showed minimal response to 30min hypoxia-ischemia alone, BALB/c demonstrated a moderate response, and both CD1 and FVB revealed the highest brain damage. LPS pre-sensitization led to substantial increase in overall brain infarction, microglial and astrocyte response and cell death in four of the five strains, with exception of BALB/c that only showed a significant effect with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Saline administration prior to hypoxia-ischemia resulted in an increase in inflammatory-associated markers, particularly in the astroglial activation of C57BL/6 mice, and in combined microglial activation and neuronal cell loss in FVB mice. Finally, two of the four strongly affected strains--C57BL/6 and CD1--revealed pronounced contralateral astrogliosis with a neuroanatomical localization similar to that observed on the occluded hemisphere. Overall, the current findings demonstrate strain differences in response to hypoxia-ischemia alone, to stress associated with vehicle injection, and to LPS-mediated pre-sensitization, which partially explains the high variability seen in the neonatal mouse models of hypoxia-ischemia. These results can be useful in future studies of fetal/neonatal response to inflammation and reduced oxygen-blood supply.

The hopes and fears of in utero gene therapy for genetic disease--a review.

Somatic gene delivery in utero is a novel approach to gene therapy for genetic disease. It is based on the concept that application of gene therapy vectors to the fetus in utero may prevent the development of early disease related tissue damage, may allow targeting of otherwise inaccessible organs, tissues and still expanding stem cell populations and may also provide postnatal tolerance against the therapeutic transgenic protein. This review outlines the hypothesis and scientific background of in utero gene therapy and addresses some of the frequently expressed concerns raised by this still experimental, potentially preventive gene therapy approach. We describe and discuss the choice of vectors, of animal models and routes of administration to the fetus. We address potential risk factors of prenatal gene therapy such as vector toxicity, inadvertent germ line modification, developmental aberration and oncogenesis as well as specific risks of this procedure for the fetus and mother and discuss their ethical implications.

Analysis of manual reticulocyte counting.

A statistical appraisal of manual reticulocyte enumeration was extensively investigated. Statistically, the counting variability among technologists was significantly worse than expected for a counting (Poisson) process. the proportional error associated with each technologist can exceed 39%. The technologist-to-technologist variation is the major source of inaccuracy at all reticulocyte levels and is attributed to the consistent application of individual criteria in reticulocyte identification. Although results may be clinically useful, it is extremely difficult to obtain manual results with sufficient accuracy to serve as a "reference" reticulocyte method.

Extended leukocyte parameters for hematology analyzers.

Newly introduced, extended leukocyte parameters on laser-based hematology analyzers permit normal samples to be readily identified allowing these samples to be excluded from manual analysis. This enables more hematology laboratory resources to be focused on abnormal specimens. A new reagent that lyses erythrocytes while leaving the optical properties of the leukocytes unaltered is used. A special optical bench measures both narrow-angle forward light scatter (an indicator of cell size) and wide-angle light scatter (an indicator of cell granularity). The two scatter measurements are combined to produce a histogram in which lymphocytes, monocytes, and granulocytes are clearly delineated. A microprocessor detects the separation between histogram peaks, sets the proper thresholds, produces the three-part count, and indicates abnormal samples on the basis of histogram peak position, shape, and resolution. In a clinical study correlations between instrument counts and manual leukocyte differentials were very good. The potential for reducing the number of manual differentials of normal samples is significant.