Nonlinear Ultrafast Spin Scattering in the Skyrmion Phase of Cu_{2}OSeO_{3}

Ultrafast x-ray scattering studies of the topological Skyrmion phase in Cu_{2}OSeO_{3} show the dynamics to be strongly dependent on the excitation energy and fluence. At high photon energies, where the electron-spin scattering cross section is relatively high, the excitation of the topological Skyrmion phase shows a nonlinear dependence on the excitation fluence, in contrast to the excitation of the conical phase which is linearly dependent on the excitation fluence. The excitation of the Skyrmion order parameter is nonlinear in the magnetic excitation resulting from scattering during electron-hole recombination, indicating different dominant scattering processes in the conical and Skyrmion phases.

The effect of antenatal lifestyle advice for women who are overweight or obese on secondary measures of neonatal body composition: the LIMIT randomised trial

OBJECTIVE

To evaluate the effect of providing antenatal dietary and lifestyle advice on neonatal anthropometry, and to determine the inter-observer variability in obtaining anthropometric measurements.

DESIGN

Randomised controlled trial.

SETTING

Public maternity hospitals across metropolitan Adelaide, South Australia.

POPULATION

Pregnant women with a singleton gestation between 10(+0) and 20(+0) weeks, and body mass index (BMI) ≥25 kg/m(2).

METHODS

Women were randomised to either Lifestyle Advice (comprehensive dietary and lifestyle intervention over the course of pregnancy including dietary, exercise and behavioural strategies, delivered by a research dietician and research assistants) or continued Standard Care. Analyses were conducted using intention-to-treat principles.

MAIN OUTCOME MEASURES

Secondary outcome measures for the trial included assessment of infant body composition using body circumference and skinfold thickness measurements (SFTM), percentage body fat, and bio-impedance analysis of fat-free mass.

RESULTS

Anthropometric measurements were obtained from 970 neonates (488 Lifestyle Advice Group, and 482 Standard Care Group). In 394 of these neonates (215 Lifestyle Advice Group, and 179 Standard Care Group) bio-impedance analysis was also obtained. There were no statistically significant differences identified between those neonates born to women receiving Lifestyle Advice and those receiving Standard Care, in terms of body circumference measures, SFTM, percentage body fat, fat mass, or fat-free mass. The intra-class correlation coefficient for SFTM was moderate to excellent (0.55-0.88).

CONCLUSIONS

Among neonates born to women who are overweight or obese, anthropometric measures of body composition were not modified by an antenatal dietary and lifestyle intervention.

The effect of anaemia on hospital length of stay in lumbar decompression and fusion procedures

Ways of reducing the length of hospital stay have received increased attention in recent years. Both preoperative and postoperative anaemia have been implicated as causative agents in increasing postoperative length of stay (LOS). In a retrospective study, 317 patients that underwent lumbar decompression and fusion surgery were assessed. Two separate block multivariate linear regression analyses were performed to evaluate the impact of preoperative anaemia, postoperative anaemia, and the degree of perioperative haemoglobin drop on LOS. Other anaemia related factors were also assessed. Preoperative anaemia, postoperative anaemia, and the amount of perioperative haemoglobin drop were all shown to prolong the length of hospitalisation and therefore to increase overall healthcare costs. Following strict anaemia corrective maneuvers could reasonably be expected to reduce expenditure.

Imaging Molecular Motion: Femtosecond X-Ray Scattering of an Electrocyclic Chemical Reaction

Structural rearrangements within single molecules occur on ultrafast time scales. Many aspects of molecular dynamics, such as the energy flow through excited states, have been studied using spectroscopic techniques, yet the goal to watch molecules evolve their geometrical structure in real time remains challenging. By mapping nuclear motions using femtosecond x-ray pulses, we have created real-space representations of the evolving dynamics during a well-known chemical reaction and show a series of time-sorted structural snapshots produced by ultrafast time-resolved hard x-ray scattering. A computational analysis optimally matches the series of scattering patterns produced by the x rays to a multitude of potential reaction paths. In so doing, we have made a critical step toward the goal of viewing chemical reactions on femtosecond time scales, opening a new direction in studies of ultrafast chemical reactions in the gas phase.

Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5

Terahertz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structures. In complex oxides, this method has been used to melt electronic order, drive insulator-to-metal transitions and induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature (300 kelvin) in YBa2Cu3O6+x (refs 9, 10). Here we report the crystal structure of this exotic non-equilibrium state, determined by femtosecond X-ray diffraction and ab initio density functional theory calculations. We find that nonlinear lattice excitation in normal-state YBa2Cu3O6+x at above the transition temperature of 52 kelvin causes a simultaneous increase and decrease in the Cu-O2 intra-bilayer and, respectively, inter-bilayer distances, accompanied by anisotropic changes in the in-plane O-Cu-O bond buckling. Density functional theory calculations indicate that these motions cause drastic changes in the electronic structure. Among these, the enhancement in the character of the in-plane electronic structure is likely to favour superconductivity.

Hypnosis antenatal training for childbirth: a randomised controlled trial

OBJECTIVE

To determine the use of pharmacologic analgesia during childbirth when antenatal hypnosis is added to standard care.

DESIGN

Randomised controlled clinical trial, conducted from December 2005 to December 2010.

SETTING

The largest tertiary referral centre for maternity care in South Australia.

POPULATION

A cohort of 448 women at >34 weeks of gestation, with a singleton pregnancy and cephalic presentation, planning a vaginal birth. Exclusions were: the need for an interpreter; pre-existing pain; psychiatric illness; younger than 18 years; and previous experience of hypnosis for childbirth.

METHODS

All participants received usual care. The group of women termed Hypnosis + CD (hypnotherapist guided) were offered three antenatal live hypnosis sessions plus each session's corresponding audio CD for further practise, as well as a final fourth CD to listen to during labour. The group of women termed CD only (nurse administered) were played the same antenatal hypnosis CDs as group 1, but did not receive live hypnosis training. The control group participants were given no additional intervention or CDs.

MAIN OUTCOME MEASURE

Use of pharmacological analgesia during labour and childbirth.

RESULTS

No difference in the use of pharmacological analgesia during labour and childbirth was found comparing hypnosis + CD with control (81.2 versus 76.2%; relative risk, RR 1.07; 95% confidence interval, 95% CI 0.95-1.20), or comparing CD only with control (76.9 versus 76.2%, RR 1.01, 95% CI 0.89-1.15).

CONCLUSIONS

Antenatal group hypnosis using the Hypnosis Antenatal Training for Childbirth (HATCh) intervention in late pregnancy does not reduce the use of pharmacological analgesia during labour and childbirth.

Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La(1.75)Sr(0.25)NiO(4) nickelate crystals using time-resolved resonant x-ray diffraction

We investigate the order parameter dynamics of the stripe-ordered nickelate, La(1.75)Sr(0.25)NiO(4), using time-resolved resonant x-ray diffraction. In spite of distinct spin and charge energy scales, the two order parameters' amplitude dynamics are found to be linked together due to strong coupling. Additionally, the vector nature of the spin sector introduces a longer reorientation time scale which is absent in the charge sector. These findings demonstrate that the correlation linking the symmetry-broken states does not unbind during the nonequilibrium process, and the time scales are not necessarily associated with the characteristic energy scales of individual degrees of freedom.

Phosphorus flux from wetland ditch sediments

The accumulation of phosphorus (P) in the bottom sediment of field drainage ditches poses a threat to the ecology both of the ditch water and downstream water courses. We investigated the amounts, forms and internal loading of sediment-bound P along two drainage ditches that regulate water levels in a basin fen (~200 ha) supporting a mixture of restored wetland and drained agricultural fields. Water levels in the Lady's Drove Rhyne are currently managed to enhance the biodiversity of the wetland (Catcott Lows Reserve - an area formerly cultivated for arable crop production); whereas, the East Ditch is managed to drain adjoining land that remains under arable and livestock production. Laboratory-based chemical fractionation schemes were used to characterise the forms and potential mobility of the sediment-bound P, whilst pore-water equilibrators were employed in situ to evaluate the diffusive flux of P through the sediment-water column, and to characterise the corresponding redox conditions. Along both ditches, sediment pore-water profiles indicated conditions ranging from weakly to very reducing conditions with increasing depth, and net fluxes of P from the sediment to overlying water. P flux values ranged from 0.33 to 1.30 mg m(-2) day(-1). Both the degree of P saturation (DPS) of the sediment and NaOH extractable (Fe/Al-bound) P correlated significantly (P<0.05) with P flux. Both in the wetland and agricultural ditches, by far the highest values for P flux were recorded at sites closest to points of drainage water entry from the corresponding, adjoining land. Although the P flux data were obtained from only a single sampling event, this study highlights the contribution of historical as well as ongoing agricultural land use on the sustained elevated P status of ditch sediments in lowland catchments.

Invited review article: technology for attosecond science

We describe a complete technological system at Imperial College London for Attosecond Science studies. The system comprises a few-cycle, carrier envelope phase stabilized laser source which delivers sub 4 fs pulses to a vibration-isolated attosecond vacuum beamline. The beamline is used for the generation of isolated attosecond pulses in the extreme ultraviolet (XUV) at kilohertz repetition rates through laser-driven high harmonic generation in gas targets. The beamline incorporates: interferometers for producing pulse sequences for pump-probe studies; the facility to spectrally and spatially filter the harmonic radiation; an in-line spatially resolving XUV spectrometer; and a photoelectron spectroscopy chamber in which attosecond streaking is used to characterize the attosecond pulses. We discuss the technology and techniques behind the development of our complete system and summarize its performance. This versatile apparatus has enabled a number of new experimental investigations which we briefly describe.

Elective birth at 37 weeks of gestation versus standard care for women with an uncomplicated twin pregnancy at term: the Twins Timing of Birth Randomised Trial

OBJECTIVE

To evaluate whether for women with an uncomplicated twin pregnancy, elective birth at 37 weeks of gestation was associated with reduced risk of death or serious outcomes for babies, without increasing harm.

DESIGN

Randomised controlled trial.

SETTING

Maternity hospitals across Australia, New Zealand and Italy.

POPULATION

A total of 235 women with an uncomplicated twin pregnancy at 36(+6) weeks of gestation, with no contraindication to continuing their pregnancy.

METHODS

Using a computer-generated, central telephone randomisation service, 235 women were randomised to Elective Birth (birth at 37 weeks; n=116) or Standard Care (continued expectant management, with birth planned from 38 weeks; n=119). Outcome assessors were masked to treatment allocation.

MAIN OUTCOME MEASURE

A composite of serious adverse outcome for the infant.

RESULTS

For women with an uncomplicated twin pregnancy, elective birth at 37 weeks of gestation was associated with a significant reduction in risk of serious adverse outcome for the infant (Elective Birth 11/232 [4.7%] versus Standard Care 29/238 [12.2%]; risk ratio [RR] 0.39; 95% CI 0.20-0.75; P=0.005), reflecting a reduction in birthweight less than the third centile using singleton gestational age-specific charts (Elective Birth 7/232 [3.0%] versus Standard Care 24/238 [10.1%]; RR 0.30; 95% CI 0.13-0.67; P=0.004). In a post hoc analysis using twin gestational age-specific charts, there was evidence of a trend towards a reduction in the primary composite of serious adverse infant outcome (Elective Birth Group 4/232 [1.7%] versus Standard Care Group 12/238 [5.0%]; RR 0.34; 95% CI 0.11 to 1.05; P=0.06).

CONCLUSION

The findings of our study support recommendations for women with an uncomplicated twin pregnancy to birth at 37 weeks of gestation.

Review: Placental programming of postnatal diabetes and impaired insulin action after IUGR

Being born small due to poor growth before birth increases the risk of developing metabolic disease, including type 2 diabetes, in later life. Inadequate insulin secretion and decreasing insulin sensitivity contribute to this increased diabetes risk. Impaired placental growth, development and function are major causes of impaired fetal growth and development and therefore of IUGR. Restricted placental growth (PR) and function in non-human animals induces similar changes in insulin secretion and sensitivity as in human IUGR, making these valuable tools to investigate the underlying mechanisms and to test interventions to prevent or ameliorate the risk of disease after IUGR. Epigenetic changes induced by an adverse fetal environment are strongly implicated as causes of later impaired insulin action. These have been well-characterised in the PR rat, where impaired insulin secretion is linked to epigenetic changes at the Pdx-1 promotor and reduced expression of this transcription factor. Present research is particularly focussed on developing intervention strategies to prevent or reverse epigenetic changes, and normalise gene expression and insulin action after PR, in order to translate this to treatments to improve outcomes in human IUGR.

Ideal waveform to generate the maximum possible electron recollision energy for any given oscillation period

We present the perfect waveform which, during a strong field interaction, generates the maximum possible electron recollision energy for any given oscillation period, over 3 times as high as that for a pure sinusoidal wave. This ideal waveform has the form of a linear ramp with a dc offset. A genetic algorithm was employed to find an optimized practically achievable waveform composed of a longer wavelength field, to provide the offset, in addition to higher frequency components. This second waveform is found to be capable of generating electron recollision energies as high as those for the perfect waveform while retaining the high recollision amplitudes of a pure sinusoidal wave. Calculations of high harmonic generation demonstrate this enhancement, by increasing the cutoff energy by a factor of 2.5 while maintaining the harmonic yield, providing an enhanced tool for attosecond science.

163. MATERNAL FOLIC ACID SUPPLEMENTATION INDUCED ALTERATIONS IN METABOLIC HEALTH OF PROGENY: ROLE OF microRNA REGULATORY NETWORKS

Background: Nutrition in early life can influence metabolic functionality in later life, in part via heritable epigenetic changes, which modify gene expression without altering DNA sequence. Folate supplies methyl groups for the methylation of DNA and histones, both major epigenetic marks that change dynamically in utero. We have recently shown that maternal folic acid supplementation (MFAS) in the pregnant rat increases insulin sensitivity in adult male progeny, while decreasing that of females. The molecular basis of this is unknown but microRNAs may play a role. MicroRNAs are epigenetically regulated non-coding RNAs that downregulate post-transcriptional expression of their targets. MFAS may modulate epigenetics and expression of microRNAs and their targets in adult progeny to alter insulin sensitivity. Aims/Hypotheses: The effect of MFAS before and throughout pregnancy on microRNA expression in liver and skeletal muscle of adult progeny was determined. Methods: Female Wistar rats were fed Control (n=11) or Folic Acid Supplemented (n=9) diets containing either 2 or 6 mg folic acid/kg respectively, from two weeks before mating and throughout pregnancy. One male and female progeny per litter were sacrificed on postnatal day 90 and microRNA expression was determined by Exiqon microRNA microarray v.8.1. Results: MFAS altered hepatic microRNA expression in adult male progeny, but did not alter that in females. Sixteen hepatic microRNAs were differentially expressed, with five predicted in silico (rno-miR: 23a, 23b, 212, 298 and 325-5p) to target several key insulin signalling molecules (p85α, p110β, Akt2, and Prkcz). miR-122a, which promotes cholesterol and lipid synthesis in vivo, was also downregulated. MFAS did not alter microRNA expression in skeletal muscle of adult male or female progeny. Conclusions: MFAS alters hepatic microRNA expression in adult male progeny. Changes in their expression together with their targets in insulin signalling pathway may initiate increased insulin sensitivity in adult male progeny.

162. THE EFFECT OF MATERNAL FOLIC ACID SUPPLEMENTATION THROUGHOUT PREGNANCY ON NEURODEVELOPMENT, MOTOR FUNCTION AND BEHAVIOUR OF PROGENY IN THE RAT

Background: Maternal folic acid supplementation (mFAS) during early pregnancy is recommended to reduce the incidence of neural tube defects and has recently been associated with improved neurodevelopment in children. However, the effect on neurodevelopment of mFAS from before conception and throughout pregnancy is unknown. We examined the effect of mFAS throughout the gestational period on postnatal growth, neurodevelopment and early adult motor function and behaviour in rat offspring. Methods: Female Wistar Rats were fed either a control (folic acid 2mg/kg, n=6) or moderate mFAS diet (folic acid 6mg/kg, n=6) from two weeks before mating with Lewis males, until birth of progeny. Male and female progeny (Control=36, mFAS=36) were weighed on postnatal day (PD) 3, 7, 14, 21, 40 and 90, and underwent various tests between PD4 and 14: righting reflex, palm-grasp reflex, negative geotaxis, forelimb hanging, ascent test and eye opening. Locomotor/ exploratory behaviour, motor coordination and anxiety were assessed using an open field test (PD52), rotarod (PD55) and elevated plus maze (PD58) (Control=24, mFAS=24). Results: mFAS did not alter maternal weight gain, litter-size at birth or progeny growth between PD3-90. mFAS tended to increase righting reflex time (p=0.057) and impair ascent ability (p=0.085). Negative geotaxis time was reduced at PD7 but not later (Diet x Age p=0.051). mFAS increased the proportion of progeny with eyes open at PD14 (p=0.008) and tended to increase forelimb hanging time(p=0.097). mFAS did not alter motor learning/function (rotarod), but increased ambulatory and exploratory behaviour (open field test; p=0.027). Conclusions: mFAS delays some early aspects of neurodevelopment including neonatal postural reflex maturation and proprioceptive/vestibular function, but accelerates others such as eye opening. However, the open field test indicated that mFAS improved the offspring's locomotion and exploratory behaviours in adulthood. Further studies will differentiate the neurodevelopmental effects of mFAS around conception from gestation-long mFAS.

Dynamic two-center interference in high-order harmonic generation from molecules with attosecond nuclear motion

We report a new dynamic two-center interference effect in high-harmonic generation from H2, in which the attosecond nuclear motion of H2+ initiated at ionization causes interference to be observed at lower harmonic orders than would be the case for static nuclei. To enable this measurement we utilize a recently developed technique for probing the attosecond nuclear dynamics of small molecules. The experimental results are reproduced by a theoretical analysis based upon the strong-field approximation which incorporates the temporally dependent two-center interference term.

The pars intermedia and the fetal pituitary-adrenal axis

The increased production of cortisol by the fetal adrenal gland at term acts as the trigger for parturition in some species. The fetal pituitary controls fetal adrenal function. However, ACTH is only one of a family of closely related peptides which derive from a common precursor and we have shown that although ACTH is the dominant form in the adult pituitary, the expression of the "family trees' is altered in the fetus. In the sheep, it is large-molecular-weight precursors and, in the primate, the smaller peptides such as alpha-MSH, CLIP, beta-MSH and beta-endorphin that predominate in fetal life and which may be responsible for fetal adrenal function. It is still unclear what causes the developmental change in the ACTH "family tree'. Since it may result from a change in pituitary function - from the peptides of the pars intermedia, in the fetus, to those of pars anterior, in the adult - we have studied these two lobes separately in pituitaries taken from adult and fetal sheep and monkeys. Our preliminary results suggest that the change may occur in the neurointermediate lobe in the primate, but that in the sheep the developmental changes occur in the anterior lobe.

Effects of short-term pH fluctuations on cadmium, nickel, lead, and zinc availability to ryegrass in a sewage sludge-amended field

In this field experiment, sewage sludge was applied at 0, 5, 10, and 50tha(-1), and the availability of Cd, Ni, Pb, and Zn was assessed both by ryegrass uptake and by DTPA extractions. The aim was to investigate the role of important soil parameters, particularly pH, on heavy metal availability. It was found that metal uptake and extractability increased significantly in the 50tha(-1) treatment. In the 16th week of the experiment there was a significant, although temporary, increase in DTPA-extractable Cd, Ni, and Zn concentrations. Metal concentrations in ryegrass were also significantly elevated in week 20 compared to the subsequent cuttings. These fluctuations in both DTPA and ryegrass uptake occurred only at 50tha(-1) and were probably induced by a sudden pH decrease measured in the same treatment in week 16. This suggests that soils which have received high applications of sewage sludge may be prone to fluctuations in metal availability.

Full-trajectory diagnosis of laser-driven radiative blast waves in search of thermal plasma instabilities

Experimental investigations into the dynamics of cylindrical, laser-driven, high-Mach-number shocks are used to study the thermal cooling instability predicted to occur in astrophysical radiative blast waves. A streaked Schlieren technique measures the full blast-wave trajectory on a single-shot basis, which is key for observing shock velocity oscillations. Electron density profiles and deceleration parameters associated with radiative blast waves were recorded, enabling the calculation of important blast-wave parameters including the fraction of radiated energy, epsilon, as a function of time for comparison with radiation-hydrodynamics simulations.

The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery

We present the results of a retrospective study employing intraoperative micro-Doppler ultrasonography (MDU) in verifying proper clip placement during cerebral aneurysmal surgery. One hundred and thirty-four patients surgically treated for 147 intracranial aneurysms were studied. Thirteen patients harboring 17 aneurysms were surgically treated on an elective basis, while 121 patients with 130 aneurysms, presented with subarachnoid hemorrhage (SAH). Blood flow velocities of the parent and adjacent vessels as well as the aneurysmal sac were measured using a Conforma Micro-Doppler (Cook Vascular Inc., Leechburg, PA, USA). Pre- and post-operative cerebral angiography was obtained in all our patients. In 23 aneurysms (15.6%) there was decreased or absent flow in the parent vessel or in one of the adjacent vessels after clipping. In another 19 aneurysms (12.9%), MDU demonstrated flow through the aneurysmal dome even though the aneurysmal neck appeared to be totally obliterated. Presence of SAH, anatomic location and size of the aneurysm were associated with improper clip placement in a statistically significant fashion. The false positive rate for MDU was 2% while there were no false negative findings in our study. MDU appears to be a non-invasive, reliable alternative methodology to intra-operative angiography. This inexpensive method may lend itself to routine usage in aneurysm surgery.

Sex-specific effects of placental restriction on components of the metabolic syndrome in young adult sheep

Prenatal and early postnatal life experiences, reflected by size at birth and postnatal catch-up growth, contribute to the risk of developing the metabolic syndrome in adulthood, but their relative importance is unclear. Therefore, we determined the effects of restricted placental and fetal growth on components of the metabolic syndrome in young adult sheep and the relationships of the latter to size at birth and early postnatal growth. Fasting plasma metabolites, glucose tolerance (by intravenous glucose tolerance test, IVGTT), insulin secretion and sensitivity, and resting blood pressure were measured in 22 control and 20 placentally restricted (PR) 1-yr-old sheep. In male sheep, PR increased the initial rise in glucose during an IVGTT and reduced diastolic blood pressure, and small size at birth independently predicted reduced adult size, glucose tolerance, and fasting plasma insulin and insulin disposition of glucose metabolism but increased insulin disposition of circulating FFAs. Also in males, high fractional growth rates in early postnatal life independently predicted impaired early glucose clearance during an IVGTT. In female animals, PR increased insulin sensitivity of glucose metabolism and reduced fasting plasma FFAs, and thinness at birth predicted increased adult size, fasting blood glucose, and pulse pressure. In conclusion, PR and small size at birth are associated with more components of the metabolic syndrome in adult male than in adult female sheep, with few independent effects of early postnatal growth. These sex differences in the onset and extent of adverse metabolic consequences after prenatal restraint in the sheep are consistent with observations in humans.

Probing orbital structure of polyatomic molecules by high-order harmonic generation

The effects of electronic structure and symmetry are observed in laser driven high-order harmonic generation for laser aligned conjugated polyatomic molecular systems. The dependence of the harmonic yield on the angle between the molecular axis and the polarization of the driving laser field is seen to contain the fingerprint of the highest occupied molecular orbitals in acetylene and allene, a good quantitative agreement with calculations employing the strong field approximation was found. These measurements support the extension of the recently proposed molecular orbital imaging techniques beyond simple diatomic molecules to larger molecular systems.

Supratentorial epidural hematoma of traumatic etiology in infants

INTRODUCTION AND BACKGROUND

Traumatic epidural hematoma (EDH) represents a rare head injury complication in infants. Its diagnosis can be quite challenging because its clinical presentation is usually subtle and nonspecific. In our current communication, we present our data regarding the presentation of infants with EDH, their management, and their long-term outcome.

MATERIALS AND METHODS

In a retrospective study, the hospital and outpatient clinic charts and imaging studies (head CT and skull X-rays) of 31 infants with pure, supratentorial EDH of traumatic origin were meticulously reviewed. Children Coma Scale score and Trauma Infant Neurologic Score (TINS) were also reviewed. The most common presenting symptom was irritability, which occurred in 18/31 (58.1%) of our patients. Pallor (in 30/31 patients) and cephalhematoma (in 21/31 patients) were the most commonly occurring clinical signs upon admission; both signs represent signs of significant clinical importance. Surgical evacuation via a craniotomy was required in 24/31 of our patients, while 7/31 patients were managed conservatively. The mortality rate in our series was 6.5% (2/31 patients), and our long-term morbidity rate was 3.2% (1/31 patients).

CONCLUSIONS

EDH in infants represents a life-threatening complication of head injury, which requires early identification and prompt surgical or conservative management depending on the patient's clinical condition, size of EDH, and presence of midline structure shift on head CT scan. Mortality and long-term morbidity are low with early diagnosis and prompt treatment.

Spontaneous resolution of acute cranial subdural hematomas

Acute cranial subdural hematoma (SDH) represents a common consequence of traumatic brain injury. The vast majority of acute SDHs larger than 10mm in thickness require immediate surgical evacuation. In rare occasions, however, spontaneous resolution may occur. In our current communication, we present four cases of spontaneous resolution of acute cranial SDH. Further more, the proposed theories explaining spontaneous resolution of acute SDH, as well as, clinical parameters and imaging characteristics that might predict such phenomenon, are also reviewed. The possibility of spontaneous resolution of an acute SDH, although remote, may impact the decision making process regarding the management of these patients under certain conditions.

Anatomical hemispherectomy

INTRODUCTION

Anatomical hemispherectomy is frequently employed in the surgical management of pediatric patients with medically refractory epilepsy.

MATERIALS AND METHODS

In this chapter, we review the historical evolution of this surgical procedure, outline the indications and the criteria for selecting surgical candidates and describe the important pre-operative evaluation of the surgical candidates.

DISCUSSION

We provide a detailed description of our surgical technique, anesthesiological considerations, and post-operative care plan. Ultimately we analyze the most common complications associated with this procedure.

CONCLUSION

Anatomical hemispherectomy performed in carefully selected pediatric patients with medically intractable epilepsy can be a safe and efficacious surgical procedure.

Gender differences in the insulin-like growth factor axis response to a glucose load

AIMS

The insulin-like growth factors (IGFs) are thought to contribute to glucose homeostasis. The aim of our study was to examine the response of the IGFs and their binding proteins to an intravenous load of glucose in a cohort of young men and women with normal glucose tolerance.

METHODS

The intravenous glucose tolerance test (IVGTT) was used to quantify insulin sensitivity and insulin secretion in 160 adults aged 20-21 years in Adelaide, Australia. Serum IGF-I, IGF-II, IGF-binding protein (IGFBP)-1 and IGFBP-3 were measured during the IVGTT.

RESULTS

Women were less insulin sensitive than men with higher fasting insulin (women 55.6 +/- 4.4, men 44.1 +/- 3.6 pmol L(-1), P = 0.001) and first phase insulin secretion (women 3490 +/- 286, men 3038 +/- 271 pmol L(-1) min, P = 0.042). Women showed lower fasting free IGF-I (women 0.29 +/- 0.02, men 0.36 +/- 0.02 mug L(-1), P = 0.004) but higher IGFBP-3 (women 46.3 +/- 0.53, men 43.3 +/- 0.58 mg dL(-1), P = 0.001) and higher IGFBP-1 concentrations (women 37.0 +/- 2.9, men 24.8 +/- 2.3 mug L(-1), P = 0.012). IGFBP-1 fell by 5 min and remained suppressed. IGFBP-3 and total IGF-I fell until 60 min rising again by 2 h. IGF and IGFBP values were all higher in women. IGFBP-1 showed a negative association with fasting and stimulated insulin concentrations in both genders. First phase insulin secretion however showed positive correlations with IGFBP-3 (r = 0.321, P = 0.004) and IGF-I (r = 0.339 P = 0.002) in men but not women.

CONCLUSION

Our data show that IGFBP-1, IGFBP-3 and IGF-I show acute changes following a glucose load and there are marked gender differences in these responses.

Long-term surgical outcome in patients with intracranial hydatid cyst

BACKGROUND

Cerebral hydatid cysts account for up to 3.6% of all intracranial space-occupying lesions, in endemic countries. The vast majority of patients affected are children. Computed tomography (CT) and magnetic resonance imaging (MRI) have greatly contributed to a more accurate diagnosis of hydatids. However, correct pre-operative diagnosis still remains quite puzzling. Extirpation of the intact cyst is the treatment of choice, resulting in most cases to a complete recovery.

METHOD

In our retrospective study, we have reviewed 76 cases of intra-cranial hydatid disease operated on in our hospital over a 22 year period. Presenting clinical symptoms and signs and the radiological findings on CT and MRI were documented. Albendazole was given preoperatively to patients with giant (>5 cm) or multiple cysts and postoperatively to all patients. The follow-up period ranged from 12 months to 22 years and the outcome was assessed using the Glasgow Outcome Scale (GOS).

FINDINGS

Sixty seven (95.7%) of our patients were children. Increased intracranial pressure and papilledema were the predominant findings in this group, whereas focal neurological deficits were most prevalent in adults. CT and MRI revealed round cystic lesions, isodense and iso-intense respectively to cerebrospinal fluid (CSF), with no rim enhancement or perifocal edema. Multiple cysts were identified in 3 cases. Extirpation of the cyst without rupture was accomplished in 56 patients (73.7%). Recurrences occurred in 19 patients (25%). 4 patients (5.3%) died within 6 months after surgery; 3 of these patients had multiple cysts and one died shortly after the operation due to anaphylactic shock following intra-operative rupture of the cyst.

CONCLUSION

Long-term follow-up confirms that intracranial hydatid cysts should always be surgically removed without rupture; the outcome remains excellent in these cases. Correct preoperative diagnosis is vital for the successful outcome of surgery. A high index of suspicion is therefore required in endemic areas despite the availability of advanced neuro-imaging. Medical treatment with albendazole seems to be beneficial both pre- and post-operatively. Newer diagnostic methodologies, such as MR spectroscopy and MR diffusion weighted imaging, might lend themselves to the diagnosis of intracranial hydatid cysts.

Probing Proton Dynamics in Molecules on an Attosecond Time Scale

We demonstrate a technique that uses high-order harmonic generation in molecules to probe nuclear dynamics and structural rearrangement on a subfemtosecond time scale. The chirped nature of the electron wavepacket produced by laser ionization in a strong field gives rise to a similar chirp in the photons emitted upon electron-ion recombination. Use of this chirp in the emitted light allows information about nuclear dynamics to be gained with 100-attosecond temporal resolution, from excitation by an 8-femtosecond pulse, in a single laser shot. Measurements on molecular hydrogen and deuterium agreed well with calculations of ultrafast nuclear dynamics in the H2+ molecule, confirming the validity of the method. We then measured harmonic spectra from CH4 and CD4 to demonstrate a few-femtosecond time scale for the onset of proton rearrangement in methane upon ionization.

Management of intracranial meningeal hemangiopericytomas: outcome and experience

Hemangiopericytomas represent rare intracranial tumors that have a tendency to recur locally and have the unique characteristic of giving extracranial metastases. Our current communication reviews a series of patients diagnosed with hemangiopericytoma who were treated in our facility. Eleven patients with a mean age of 51.2 years underwent follow-up for a mean time of 7.1 years. Their neuroimaging preoperative evaluation included plain skull X-rays, head CT scans, brain MRI, angiograms, and (1)HMRS. Preoperative embolization of the tumor was employed in 6/11 patients. All patients underwent craniotomy for tumor resection and postoperative radiation treatment was employed on all but one. Grade I resection was accomplished in 6/11 (54.5%), grade III in 4/11 (36.4%), and grade IV in 1/11 (9.1%). Local recurrence was detected in 3/11 (27.3%) at a mean period of 5 (range 2-7.5) years. Extracranial metastatic disease was documented in 4/11 (36.4%) patients at a mean of 4.9 (range 2.5-7) years after the initial diagnosis. The GOS score was: 7/11 (63.6%) scored 5, while 4/11 (36.4%) died at a mean time of 5.5 (range 3-8) years after the initial diagnosis. Intracranial hemangiopericytomas management requires aggressive surgical resection, postoperative radiation treatment, and extensive follow-up to rule out local recurrences and delayed extracranial metastases.

Review of the literature regarding the relationship of rebleeding and external ventricular drainage in patients with subarachnoid hemorrhage of aneurysmal origin

Acute hydrocephalus is a well-documented complication of subarachnoid hemorrhage. The insertion of external ventricular drainage (EVD) has been the standard of care in the management of this complication, aiming primarily at immediate improvement of the clinical condition of these patients, making them more suitable candidates for surgical or endovascular intervention. In our current communication, we review the pertinent literature regarding the relationship of rebleeding and EVD. Several studies have implicated a significantly increased risk of rebleeding in patients with EVD, compared with patients without it. Abrupt lowering of the intracranial pressure could lead to rebleeding due to decreased transmural pressure or removal of the clot sealing the previously ruptured aneurysm. However, a variety of parameters that could affect the rebleeding rate, such as the timing of surgery, the timing and duration of drainage, the size of the aneurysm, as well as the severity of the initial hemorrhage, do not seem to have been adequately explored in the majority of these studies. In addition, a number of clinical trials have failed to provide evidence for the negative role of EVD in the development of rebleeding. Conclusively, further long-term multi-center studies are required in order to establish the exact nature of the relationship between EVD and rebleeding after aneurysmal subarachnoid hemorrhage.

Umbilical cord leptin predicts neonatal bone mass

Evidence is accumulating that the risk of osteoporosis in later life may be determined in part by environmental influences on bone development during intrauterine and early postnatal life. A potential role for fetal leptin in mediating these effects is suggested by animal studies showing that leptin influences prenatal osteoblast growth and development, and that fetal leptin concentrations are altered by changes in maternal nutrition. In a group of term human infants we reported previously that maternal birthweight, smoking, fat mass, and exercise during late pregnancy independently predict neonatal bone mass. To investigate the potential role of leptin in mediating these effects, we now relate leptin concentrations in umbilical venous serum to neonatal bone mass and body composition in 117 infants. There were strong positive associations between umbilical venous leptin concentration and each of whole body bone mineral contents (BMC) (r = 0.42, P < or = 0.001) and estimated volumetric bone density (r = 0.21, P = 0.02); whole body lean mass (r = 0.21, P < or = 0.024); and whole body fat mass (r = 0.60, P < 0.001). The associations with neonatal BMC and fat mass, but not with lean mass, were independent of associations that we have reported previously between cord serum insulin-like growth factor 1 (IGF-1) concentrations and neonatal body composition. Among the maternal determinants of neonatal bone mass, cord leptin explained the relationship with maternal fat stores, but not those with the mother's own birthweight, smoking, or physical activity. We conclude that umbilical venous leptin predicts both the size of the neonatal skeleton and its estimated volumetric mineral density. In addition, among previously documented maternal determinants of neonatal bone mass in healthy pregnancies, maternal fat stores may mediate their effect on fetal bone accrual through variation in fetal leptin concentrations.

Metyrapone infusion stimulates adrenal growth without activating the cell cycle or the IGF system in the late gestation fetal sheep

Recently, we have demonstrated that administration of metyrapone, to suppress cortisol synthesis and decrease negative feedback at the pituitary, results in an increase in circulating ACTH and adrenal growth in the late gestation sheep fetus. In these studies, we demonstrated a 2-fold increase in adrenocortical growth using morphometric techniques. To elucidate the potential molecular mechanisms leading to the increase in adrenal growth, we examined adrenal expression of the cell cycle regulatory proteins (cyclin D1) and cyclin-kinase inhibitory proteins (p16ink, p21Cip), and insulin-like growth factor-II (IGF-II), IGF-binding protein 2 (IGFBP-2) and IGF-I type 1 Receptor (IGF1R) from fetuses infused with metyrapone or vehicle for 15 days. There was a significant decrease in adrenal expression of cyclin D1 in metyrapone-(472.0 +/- 29.7) compared with vehicle-infused (662.7 +/- 29.2) fetuses. There was no significant difference, however, in the adrenal expression of the cyclin-kinase inhibitory proteins (p16ink or p21Cip) or in the IGF system (IGF-II, IGFBP-2 or IGF1R) mRNA between metyrapone- and vehicle-infused. In summary, in this model of metyrapone-activated adrenal cortical hypertrophy, growth occurs with a suppression of the rate-limiting cell cycle protein and without activation of the IGF system.

C1-C2 Transarticular Screw Fixation for Atlantoaxial Instability

OBJECTIVES

The atlantoaxial segment of the cervical spine is commonly destabilized in a variety of disorders. Transarticular screw fixation of the C1-C2 joint has been proposed as a biomechanically superior therapeutic modality. The authors present their experience with this technique.

METHODS

A retrospective analysis of 23 patients treated with this technique was performed. The mean follow-up period was 39.5 +/- 0.1 months.

RESULTS

Mean duration of hospitalization was 3.4 +/- 0.1 days (range, 2 to 11 days). No intraoperative or early postoperative complications were detected. Four patients (17.4%) had postoperative complications unrelated to the primary procedure. The position of the screw was judged as satisfactory in 21 patients (91.3%). Two patients (8.7%) with suboptimal positioning of the screws were neurologically intact but needed no reoperation. Solid osseous fusion was detected in 19 patients (82.6%).

CONCLUSIONS

Transarticular C1-C2 screw fixation appears to be a safe and surgically reliable technique. Criteria for its application and refinements in its technical considerations continue to advance its clinically versatile therapeutic potential.

The effect of intrafetal infusion of metyrapone on arterial blood pressure and on the arterial blood pressure response to angiotensin II in the sheep fetus during late gestation

While the impact of exogenous glucocorticoids on the fetal cardiovascular system has been well defined, relatively few studies have characterised the role of endogenous fetal glucocorticoids in the regulation of arterial blood pressure (BP) during late gestation. We have therefore infused metyrapone, an inhibitor of cortisol biosynthesis, into fetal sheep from 125 days gestation (when fetal cortisol concentrations are low) and from 137 days gestation (when fetal cortisol concentrations are increasing) and measured fetal plasma cortisol, 11-desoxycortisol and ACTH, fetal systolic, diastolic and mean arterial BP, heart rate, and the fetal BP responses to increasing doses of angiotensin II (AII). At 125 days gestation, there was a significant increase in fetal plasma ACTH and 11-desoxycortisol by 24 h after (+24 h) the start of the metyrapone infusion, and plasma cortisol concentrations were not different at +24 h when compared with pre-infusion values. Whilst the initial fall in circulating cortisol concentrations may have been transient, systolic, diastolic and mean arterial BP were ~5-6 mmHg lower (P < 0.05) in metyrapone- than in vehicle-infused fetuses at 24-48 h after the start of the infusion. When metyrapone was infused from 137/138 days gestation, there was a significant decrease in plasma cortisol concentrations by +6 h, which was followed by an increase back to pre-infusion values. While cortisol concentrations decreased, there was no change in fetal mean arterial BP during the first 24 h after the start of metyrapone infusion. Mean fetal arterial BP values at 137-139 days gestation were not different in fetuses that had been infused with either vehicle or metyrapone from 125 days gestation or with metyrapone from 137/138 days gestation. At 137-139 days gestation, however, arterial BP responses to increasing doses of AII were significantly blunted in fetuses that had been infused with metyrapone from 125 days gestation, when compared with fetuses that had been infused with metyrapone from 137/138 days gestation or with vehicle from 125 days gestation. The dissociation of the gestational age increase in arterial BP and the effects of intrafetal AII on fetal arterial BP indicates that increase in fetal BP with gestational age is not entirely a result of an increased vascular responsiveness to endogenous AII. Furthermore there may be a critical window during late gestation when the actions of cortisol contribute to the development of vascular responsiveness to AII.

Postnatal ontogeny of glucose homeostasis and insulin action in sheep

Glucose tolerance declines with maturation and aging in several species, but the time of onset and extent of changes in insulin sensitivity and insulin secretion and their contribution to changes in glucose tolerance are unclear. We therefore determined the effect of maturation on glucose tolerance, insulin secretion, and insulin sensitivity in a longitudinal study of male and female sheep from preweaning to adulthood, and whether these measures were related across age. Glucose tolerance was assessed by intravenous glucose tolerance test (IVGTT, 0.25 g glucose/kg), insulin secretion as the integrated insulin concentration during IVGTT, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (2 mU insulin.kg(-1).min(-1)). Glucose tolerance, relative insulin secretion, and insulin sensitivity each decreased with age (P < 0.001). The disposition index, the product of insulin sensitivity, and various measures of insulin secretion during fasting or IVGTT also decreased with age (P < 0.001). Glucose tolerance in young adult sheep was independently predicted by insulin sensitivity (P = 0.012) and by insulin secretion relative to integrated glucose during IVGTT (P = 0.005). Relative insulin secretion before weaning was correlated positively with that in the adult (P = 0.023), whereas glucose tolerance, insulin sensitivity, and disposition indexes in the adult did not correlate with those at earlier ages. We conclude that glucose tolerance declines between the first month of life and early adulthood in the sheep, reflecting decreasing insulin sensitivity and absence of compensatory insulin secretion. Nevertheless, the capacity for insulin secretion in the adult reflects that early in life, suggesting that it is determined genetically or by persistent influences of the perinatal environment.

Differential actions of metyrapone on the fetal pituitary-adrenal axis in the sheep fetus in late gestation

It is not clear if an increase in intra-adrenal cortisol is required to mediate the actions of adrenocorticotropic hormone (ACTH) on adrenal growth and steroidogenesis during the prepartum stimulation of the fetal pituitary-adrenal axis. We infused metyrapone, a competitive inhibitor of cortisol biosynthesis, into fetal sheep between 125 and 140 days of gestation (term = 147 +/- 3 days) and measured fetal plasma cortisol, 11-desoxycortisol, and ACTH; pituitary pro-opiomelanocortin mRNA and adrenal expression of ACTH receptor (melanocortin type 2 receptor), steroidogenic acute regulatory protein (StAR), 11beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2), cytochrome P450 cholesterol side-chain cleavage (CYP11A1), cytochrome P450 17-hydroxylase (CYP17), 3beta-hydroxysteroid dehydrogenase, and cytochrome P450 21-hydroxylase mRNA; and StAR protein in the fetal adrenal gland. Plasma ACTH and 11-desoxycortisol concentrations were higher (P < 0.05), whereas plasma cortisol concentrations were not significantly different in metyrapone- compared with vehicle-infused fetuses. The ratio of plasma cortisol to ACTH concentrations was higher (P < 0.0001) between 136 and 140 days than between 120 and 135 days of gestation in both metyrapone- and vehicle-infused fetuses. The combined adrenal weight and adrenocortical thickness were greater (P < 0.001), and cell density was lower (P < 0.01), in the zona fasciculata of adrenals from the metyrapone-infused group. Adrenal StAR mRNA expression was lower (P < 0.05), whereas the levels of mature StAR protein (30 kDa) were higher (P < 0.05), in the metyrapone-infused fetuses. In addition, adrenal mRNA expression of 11betaHSD2, CYP11A1, and CYP17 were higher (P < 0.05) in the metyrapone-infused fetuses. Thus, metyrapone administration may represent a unique model that allows the investigation of dissociation of the relative actions of ACTH and cortisol on fetal adrenal steroidogenesis and growth during late gestation.

285.Increased perinatal mortality following restriction of placental and fetal growth

Intrauterine growth restriction and subsequent low birth weight in humans are associated with increased perinatal mortality and morbidity. Impaired placental function is a major cause of IUGR in humans, but its impact on perinatal survival has not been clearly defined. We have therefore investigated the effect of restriction of placental and fetal growth on perinatal survival and behaviour in the neonatal lamb. Placental growth was surgically restricted (PR) by removal of the majority of endometrial implantation sites prior to pregnancy, leaving either 6 to 7 (moderate PR) or 3 to 4 (severe PR) visible caruncles in each uterine horn, and ewes were mated following at least 10 weeks recovery. Perinatal outcomes (stillbirths and neonatal death before 3 days of age) were recorded in a cohort of 48 control (30 singleton, 18 twin) and 28 moderate PR (14 singleton, 14 twin), and 21 severe PR (11 singleton, 10 twin) lambs, and effects of PR or twinning were evaluated by Chi-square analysis. Rates of stillbirth (P = 0.006) and total perinatal deaths (P < 0.001) were higher in severe PR pregnancies than in control or moderate PR lambs, overall (see Table in PDF file). Similarly, severe PR increased stillbirths and perinatal deaths in twins alone (P = 0.003 and P = 0.015 respectively), but the effects of PR were not significant in singletons (P = 0.10, P = 0.26 respectively). Twinning increased stillbirths and perinatal deaths overall (P = 0.002, P = 0.001) and in control lambs alone (P = 0.038, P = 0.017). Restricted fetal growth due to twinning or severe surgical restriction of placental growth thus decreases perinatal survival, due to increased stillbirths. We will further investigate the characteristics of neonatal morbidity following PR by recording neonatal behaviour, including time taken to stand and suckle, in a subsequent cohort of control and PR lambs.

273.Insulin-like growth factor treatment of pregnant guinea pigs during early pregnancy promotes fetal growth

Insulin-like growth factor (IGF)-II is an important regulator of growth in many tissues and is abundantly expressed in the placenta during pregnancy. Gene ablation studies performed in mice have shown that IGF-II deficiency results in both impaired fetal and placental growth, whereas deficiency in IGF-I reduces fetal growth only. Conversely, maternal IGF supplementation in early pregnancy in the guinea pig increases placental and fetal size by mid pregnancy. This study aimed to determine whether these anabolic effects persist into late pregnancy after cessation of treatment. On Day 20 of pregnancy, mothers were anaesthetised and a mini osmotic pump was implanted subcutaneously, to deliver 1mg/kg/day IGF-I (n = 7), IGF-II (n = 9) or vehicle (n = 7) for 17 days. Guinea pigs were killed on Day 62 of pregnancy (term ~67 days). Fetal and placental weights, and maternal and fetal body composition, were measured. Total litter size was unaffected by IGF treatment; however, IGF-II increased the number of viable fetuses by 26% (P = 0.01). After adjusting for the number of viable pups per litter, maternal IGF treatment increased fetal growth by increasing abdominal circumference, crown-rump length and fetal weight (fetal weight: IGF-I 79+/–2.5 g; IGF-II 78+/–2.6 g; vs vehicle 68+/–2.5 g, P = 0.02). IGF treatment did not alter absolute or relative fetal organ weights. IGF-I reduced placental weight by 9% and IGF-II increased it by 9%, but not significantly. IGF-I increased the fetal weight�:�placental weight ratio (19+/–0.9 vs 15+/–0.9, respectively P = 0.043). IGF treatment did not affect maternal weight gain during pregnancy nor net carcass weight; however, IGF-I reduced maternal lung and adipose tissue weights. In conclusion, maternal IGF-II treatment during early pregnancy improved fetal growth into late gestation, possibly by modulating placental efficiency. As poor placental development is implicated in fetal growth restriction, increasing maternal IGF abundance in early to mid pregnancy may be a potential therapeutic approach to placental insufficiency.

Disassociation between intracranial and systemic temperatures as an early sign of brain death

Intracranial temperature and its normal variation, as well as its response to various pathologic conditions, has become a critical component of monitoring in neurosurgical intensive care. In a prospective clinical study of 54 neurosurgical patients, intracranial pressure, cerebral perfusion pressure, and intraventricular and systemic temperatures were monitored in a neurosurgical intensive care unit. All of our patients' intraventricular temperatures were initially higher than their systemic temperatures. In 11 patients, the intraventricular temperature became lower than the systemic temperature, in a median time of 4.43 hours (range, 4.21-5.18 hours), prior to any changes in intracranial and cerebral perfusion pressures. Reversal of the disassociation between intraventricular and systemic temperatures may be an early marker of patients with a poor prognosis.

Circulating insulin-like growth factor (IGF)-I and IGF binding proteins -1 and -3 and placental development in the guinea-pig

Restricting maternal nutrition before and throughout pregnancy in the guinea-pig restricts foetal growth in part by altering placental structural determinants of substrate transfer function. The insulin-like growth factors have been implicated in mediating these changes. To assess the role of IGF-I in placental adaptation to maternal undernutrition, we examined the associations of circulating IGF-I and IGF binding proteins -1, -3 and -4 in the mother with placental structural development. In both mid- and late pregnancy, maternal food restriction reduced maternal plasma IGF-I by 56 per cent (P<0.0005) and 50 per cent (P<0.0005) respectively, and plasma IGFBP-3 by 47 per cent (P=0.03) and 55 per cent (P=0.002), respectively. Maternal plasma IGFBP-4 was reduced by 45 per cent (P=0.041) in food restricted guinea-pigs in mid-pregnancy but not late in pregnancy, while IGFBP-1 was unaltered at both stages. Late in pregnancy, food restriction reduced the ratio of maternal circulating IGF-I to IGFBP-1 by 52 per cent (P=0.011) and increased the ratio of IGF-I to IGFBP-3 in maternal plasma by 10 per cent (P=0.011). The relationships between the maternal IGF axis and structural correlates of placental function were assessed using pooled data from both ad libitum fed and food restricted animals. In mid-pregnancy, the volume density of the maternal blood space in the placental labyrinth correlated positively with both maternal plasma IGF-I and IGFBP-3, while maternal blood space volume correlated negatively with maternal plasma IGFBP-1. In late pregnancy, placental weight correlated positively with both maternal plasma IGF-I and IGFBP-4, while the surface area of syncytiotrophoblast and weight of trophoblast correlated positively, and mean syncytiotrophoblast thickness negatively, with maternal plasma IGF-I. Late in pregnancy, the volume density and weight of syncytiotrophoblast, the surface density and total surface area of trophoblast and the volume of the maternal blood space each correlated positively, and syncytiotrophoblast thickness correlated negatively with maternal plasma IGFBP-3. Concomitantly, placental weight, placental diameter, placental volume, volume density and weight of syncytiotrophoblast, weight of foetal capillaries, syncytiotrophoblast surface density and total syncytiotrophoblast surface area in the placental labyrinth, each correlated positively with the ratio of IGF-I to IGFBP-1 in maternal plasma, while syncytiotrophoblast thickness correlated negatively with this ratio. In late pregnancy therefore, increased trophoblast abundance and placental vascularity, and a reduced barrier to diffusion between maternal and foetal blood, occurs in association with increased abundance of IGF-I and its major carrier, IGFBP-3, and a reduction in that of IGFBP-1 in maternal blood in the guinea-pig. This suggests that systemic IGF-I and modulation of its bioavailability by IGFBPs -1 and -3 within the mother may influence placental growth and differentiation in an endocrine fashion, particularly when nutrition is limited.

Medical applications of Raman spectroscopy: from proof of principle to clinical implementation

Raman spectroscopy has recently been applied ex vivo and in vivo to address various biomedical issues such as the early detection of cancers, monitoring of the effect of various agents on the skin, determination of atherosclerotic plaque composition, and rapid identification of pathogenic microorganisms. This leap in the number of applications and the number of groups active in this field has been facilitated by several technological advancements in lasers, CCD detectors, and fiber-optic probes. However, most of the studies are still at the proof of concept stage. We present a discussion on the status of the field today, as well as the problems and issues that still need to be resolved to bring this technology to hospital settings (i.e., the medical laboratory, surgical suites, or clinics). Taken from the viewpoint of clinicians and medical analysts, the potential of Raman spectroscopic techniques as new tools for biomedical applications is discussed and a path is proposed for the clinical implementation of these techniques.

Fetal growth and the fetal origins hypothesis in twins--problems and perspectives

Although there is substantial evidence from studies of singletons that small size at birth is linked with long-term adverse health effects, until recently little was known as to whether these associations extend to twins. A review of published studies suggests that at present there is little consistent evidence that birthsize in twins is associated with increased morbidity or morality. While, these findings may reflect methodological limitations, it is also argued that they arise as a consequence of the substantially different biology of fetal growth in twins.

Determination of water concentration in brain tissue by Raman spectroscopy

Brain edema is one of the most common morbidity factors in patients with intracranial neoplasms and cerebrovascular pathology. Monitoring of intracranial pressure gives only an indirect and global measure of brain swelling. We have made an assessment of the applicability of Raman spectroscopy as an alternative method for assessing brain edema, which measures the water concentration in the tissue directly. Partial least-squares models were developed on the basis of Raman spectra measured in the 2600-3800-cm(-1) region, which predict the water fraction of brain tissue in the 0.75-0.95 range, with an accuracy better than 0.01.

Fetal growth restriction: adaptations and consequences

A range of pathophysiological factors can result in a perturbation or restriction of fetal growth, and the cardiovascular, neuroendocrine and metabolic adaptations of the fetus to these stimuli will depend on their nature, timing and intensity. The critical importance of these physiological adaptations for both immediate survival and long-term health outcomes has provided an impetus for experimental studies of the nature and consequences of specific fetal adaptations to a poor intrauterine environment. This review summarizes data from recent studies that have focused on the responses of the fetal cardiovascular, sympathoadrenal, hypothalamo-pituitary-adrenal and renin-angiotensin systems to experimental restriction of placental function in the sheep and discusses the consequences of these adaptations for fetal, neonatal and adult health.