Healthy term and moderately preterm infants have similar cerebral oxygen saturation and cerebral blood flow volumes during early post-natal transition.

AIM: This pilot study evaluated changes in regional cerebral oxygen saturation and cerebral blood flow volume during the transitional period in healthy term and moderately preterm infants. METHODS: The cohort comprised 16 preterm infants and seven full-term infants with mean gestational ages of 34 and 39 weeks, respectively. Longitudinal measurements were conducted during the first three days after birth. Regional cerebral oxygen saturation was determined bilaterally by frequency domain near-infrared spectroscopy. Flow volumes were determined in internal carotid and vertebral arteries by multiplying the time-averaged velocity by the cross-sectional area: cerebral blood flow volume was calculated as the sum of flow volumes and adjusted for brain weight. RESULTS: Brain weight-adjusted cerebral blood flow volumes and regional cerebral oxygen saturation were similar in preterm and term infants. Regional cerebral oxygen saturation did not correlate with brain weight-adjusted cerebral blood flow volume. Right and left brain weight-adjusted internal carotid flow volumes did not correlate with right and left regional cerebral oxygen saturation. CONCLUSION: Our findings suggest that during the first three days after birth there was adequate cardiorespiratory adaptation, cerebral perfusion and adequate compensation through the arterial circle of Willis in both healthy term and moderately preterm infants.

Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices.

The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance-voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.

[2-year follow-up examinations (Bayley II) in infants born at <32 weeks in a German perinatal center]. / 2-Jahres-Nachuntersuchung (Bayley) sehr kleiner Frühgeborener der Jahrgänge 2004-2007: Ergebnisse und Vollständigkeitsanalyse eines Perinatalzentrums.

BACKGROUND: Since 2008, follow-up examinations at 2 years of age with the standardized Bayley II test have become obligatory in Germany for all very low birth weight infants. AIM: We already performed such examinations before 2006. Here, we compared our data and the completeness of our examinations before and after the introduction of the obligatory 2-year follow-up. PATIENTS: From 2004-2007, 372 infants <1500 g or <32 weeks were discharged alive from our center, 19 infants died during their initial hospital stay, 2 after discharge. RESULTS: 271 patients participated in the follow-up examination at age 2 years, with the proportion of participating infants increasing from 64% to 84% after the introduction of obligatory tests. 75% of infants showed a normal development, while 4% had a severe impairment (defined as being blind (1), deaf (1) or having cerebral palsy (6), the CP rate thus being 2%). 49% of infants completed the Bayley test; the mean MDI was 100.3 (SD 10.6). There were no significant qualtitative differences in test results with the introduction of the obligatory test. CONCLUSIONS: The completeness of our follow-up increased over the years. In comparison with international data we found a low rate of severely impaired, deaf or blind VLBW infants.

Label-free detection of single nucleotide polymorphisms utilizing the differential transfer function of field-effect transistors.

We present a label-free method for the detection of DNA hybridization, which is monitored by non-metallized silicon field-effect transistors (FET) in a microarray approach. The described method enables a fast and fully electronic readout of ex situ binding assays. The label-free detection utilizing the field-effect is based on the intrinsic charge of the DNA molecules and/or on changes of the solid-liquid interface impedance, when biomolecules bind to the sensor surface. With our sensor system, usually a time-resolved, dc readout is used. In general, this FET signal suffers from sensor drift, temperature drift, changes in electrolyte composition or pH value, influence of the reference electrode, etc. In this article, we present a differential ac readout concept for FET microarrays, which enables a stable operation of the sensor against many of these side-parameters, reliable readout and a possibility for a quick screening of large sensor arrays. We present the detection of point mutations in short DNA samples with this method in an ex situ binding assay.

Field-effect sensors with charged macromolecules: characterisation by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods.

Field-effect-based capacitive electrolyte-insulator-semiconductor (EIS) sensors have been utilised for the deoxyribonucleic acid (DNA) immobilisation and hybridisation detection as well as for monitoring the layer-by-layer adsorption of polyelectrolytes (anionic poly(sodium 4-styrene sulfonate) (PSS) and cationic poly(allylamine hydrochloride) (PAH)). The EIS sensors with charged macromolecules have been systematically characterised by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods. The effect of the number and polarity of the polyelectrolyte layers on the shift of the capacitance-voltage curves has been investigated. Alternating potential shifts of about 30-90 mV have been observed after the adsorption of each polyanion and polycation layer, respectively. The DNA immobilisation and hybridisation signals were 35-55 and 24-33 mV, respectively. The possible mechanisms for the sensor responses are discussed.

Inkjet printing of UV-curable adhesive and dielectric inks for microfluidic devices.

Bonding of polymer-based microfluidics to polymer substrates still poses a challenge for Lab-On-a-Chip applications. Especially, when sensing elements are incorporated, patterned deposition of adhesives with curing at ambient conditions is required. Here, we demonstrate a fabrication method for fully printed microfluidic systems with sensing elements using inkjet and stereolithographic 3D-printing.

Enzyme logic AND-Reset and OR-Reset gates based on a field-effect electronic transducer modified with multi-enzyme membrane.

Capacitive field-effect sensors modified with a multi-enzyme membrane have been applied for an electronic transduction of biochemical signals processed by enzyme-based AND-Reset and OR-Reset logic gates. The local pH change at the sensor surface induced by the enzymatic reaction was used for the activation of the Reset function for the first time.

Partial tetrasomy 12pter-12p12.3 in a girl with Pallister-Killian syndrome: extraordinary finding of an analphoid, inverted duplicated marker.

Cytogenetic analysis in a girl with multiple congenital anomalies indicating Pallister-Killian syndrome (PKS) showed a supernumerary marker chromosome in 1/76 lymphocytes and 34/75 fibroblast metaphases. GTG-banding pattern was consistent with the chromosomal region 12pter-12q11. While fluorescence-in-situ hybridisation (FISH) with a whole chromosome 12 painting probe confirmed the origin of the marker, a chromosome 12 specific alpha-satellite probe did not hybridise to it. FISH analysis with a specific subtelomeric probe 12p showed hybridisation to both ends of the marker chromosome. High-resolution multicolour-banding (MCB) studies revealed the marker to be a der(12)(pter-->p12.3::p12.3-->pter). Summarising the FISH information, we defined the marker as an inverted duplication of 12pter-12p12.3 leading to partial tetrasomy of chromosome 12p. In skin fibroblasts, cultured at the patient's age of 1 year and 9 years, the marker chromosome was found in similar frequencies, even after several culture passages. Therefore, we consider the marker to have a functional centromere although it lacks detectable centromeric alpha-satellite sequences. To the best of our knowledge, this is the first proven analphoid marker of chromosome 12. Molecular genetic studies indicated that this marker is of paternal origin. The finding of partial tetrasomy 12pter-12p12.3 in our PKS patient allows to narrow down the critical region for PKS.

Color duplex measurement of cerebral blood flow volume: intra- and interobserver reproducibility and habituation to serial measurements in normal subjects.

Color duplex flowmetry of internal carotid and vertebral arteries permits estimation of intravascular flow volumes and global cerebral blood flow volume (CBFV) by summing the flow volumes measured in each of the four extracranial vessels. Intravascular flow volumes were calculated as the product of angle-corrected time-averaged flow velocity and the cross-sectional area of the vessel. The reliability of this new method was tested in a prospective, intra- and interdiane, intra- and interobserver reproducibility study of 32 healthy subjects aged 7-57 years. In each subject, CBFV was tested by each observer twice on day 1 and once on day 2 in consecutive recordings. In each artery, both examiners found closely similar mean intravascular flow volumes. Intradiane interobserver reproducibility of CBFV was high on both days (correlation coefficient, CC, 0.90 and 0.85, p < or = 0.0001; coefficient of variance, CV, 10.0 and 10.4%, respectively), as was the interdiane comparison (CC = 0.81, p < or = 0.0001; CV < or = 13.3%). Intraobserver reproducibility was even higher. On both days, there was a progressive decrease in CBFV from each subject's first to the last examination within a 1-h examination period (day 1: 717 +/- 150 ml/min to 690 +/- 120 ml/min; difference, p < or = 0.05; day 2: 700 +/- 120 ml/min to 665 +/- 126 ml/min; difference, p < or = 0.01). This habituation effect was more pronounced in subjects with high initial CBFV. Reproducibility of CBFV is comparable to that of mean CBF measurements with 133Xe inhalation and H2 15(O) positron emission tomography techniques reported by other groups. This method makes serial bedside-monitoring of CBFV feasible without posing the risks of radiation exposure.

Age dependence of total cerebral blood flow volume from childhood to adulthood.

In a prospective study of the natural development of total cerebral blood flow volume (CBFV), the common, external and internal carotid and vertebral arteries were examined in 94 healthy children and adolescents between 3 and 18 years of age (sex and age evenly distributed) using a 7.0-MHz transducer of a computed sonography system. Intravascular flow volumes were calculated with the product of angle-corrected time-averaged flow velocity and the cross-sectional area of the vessel. CBFV was determined as the sum of flow volumes in the internal carotid and vertebral arteries of both sides. CBFV increased significantly between 3 and 6.5 years of age (from 687 +/- 85 to 896 +/- 110 ml/min; age correlation, p < or = 0.01) and declined thereafter (p < or = 0.001) to a constant level of approximately 700 ml/min at 15 years of age. There was no difference in CBFV between sexes. The proportion of bilateral vertebral artery flow volume in total CBFV decreased significantly between the ages of 3 and 18 years (p < or = 0.001). As the flow volumes of the external carotid arteries increased markedly from childhood to adulthood, flow volumes of the common carotid arteries were not representative of CBFV. Intrasession test-retest correlation of CBFV was high (r = 0.89, p < or = 0.0001). Reference data for the childhood years presented here and previously described results from healthy adults allow us to outline the natural evolution of CBFV in humans. The reliability of the method has already been demonstrated. Thus, it may now be introduced into clinical application.

IL-4 and TNF-alpha induce changes in integrin expression and adhesive properties and decrease the lung-colonizing potential of HT-29 colon carcinoma cells.

The colon carcinoma cell line HT-29 was used to explore the potential of interleukin-4 (IL-4) and tumor necrosis factor alpha (TNF-alpha) to modify integrin expression and adhesive functions of tumor cells in vitro and to examine corresponding metastatic effects in vivo. Preincubation of HT-29 cells with 100 U/ml of IL-4 for 48 h downregulated the surface expression of the integrin subunits alpha 2, alpha 3, beta 1 and beta 4 after 48 h, whereas the alpha 1 subunit was upregulated. In contrast, 100 U/ml to TNF-alpha selectively upmodulated the expression of alpha v. Attachment to fibronectin of cells treated with IL-4 increased twofold (63.5% vs 32.4%). Adhesion to fibronectin (54.0% vs 32.4%) and vitronectin (37.9% vs 16.4%) was elevated in the case of TNF-alpha stimulation. Using an experimental metastasis model, HT-29 cells showed a significant reduction of their lung-colonizing potential in nude mice when preincubated with IL-4 for 48 h before intravenous injection. The decrease also observed for TNF-alpha-treated cells was less pronounced. The data indicate that the cytokines IL-4 and TNF-alpha can act as direct regulators of adhesive mechanisms of tumor cells bearing adequate receptors, thus influencing lung-colony formation.

Integrin alpha5beta1: a potent inhibitor of experimental lung metastasis.

The integrin alpha5beta1 seems to be the most relevant receptor of tumor cells for binding to fibronectin. Although numerous studies suggest a role of tumor cell fibronectin interaction in tumor metastasis, differential integrin expression on tumor cells has, however, not been correlated with metastatic capabilities. We addressed this question by transfection of the integrin alpha5beta1 cDNA into HT-29 human colon carcinoma cells which led to de novo expression of functional integrin alpha5beta1. Similar to other reports, expression of the integrin alpha5beta1 in HT-29 tumor cells exerted an inhibitory action on cell proliferation as indicated in our study by formation of fewer colonies in soft agar. The tumor growth inhibitory property of the integrin alpha5beta1 was also shown by reduction of subcutaneous xenograft growth in nude mice to approximately 50% of that of control transfectants. For the first time, we found that several clones of integrin alpha5 subunit transfectants displayed dramatically reduced formation of lung colonies and cutaneous metastasis after intravenous injection into nude mice. While most animals inoculated with control transfectant cells formed macroscopically visible lung colonies ranging from 12.6 +/- 2.6 to 22.0 +/- 6.6 (mean colony number +/- SEM), mice inoculated with HT-29 cell clones expressing the integrin alpha5beta1 were almost completely free of lung colonies (ranging from 0.0 +/- 0 to 0.2 +/- 0.1). Our results imply that integrin alpha5beta1 expression inhibits circulating tumor cells in pursuing late steps of the metastatic process as represented by the artificial metastasis (lung colonisation) model.

A complex chromosomal rearrangement with a translocation 4;10;14 in a fertile male carrier: ascertainment through an offspring with partial trisomy 14q13-->q24.1 and partial monosomy 4q27-->q28 [corrected].

Complex chromosomal rearrangements (CCRs) are usually associated with infertility or subfertility in male carriers. If fertility is maintained, there is a high risk of abnormal pregnancy outcome. Few male carriers have been identified by children presenting with mental retardation/congenital malformations (MR/CM) or by spontaneous abortions of the spouses. We report a de novo CCR with five breakpoints involving chromosomes 4, 10 and 14 in a male carrier who was ascertained through a son presenting with MR/CM due to an unbalanced karyotype with partial trisomy 14 and partial monosomy 4. The child has a healthy elder brother. In the family history no abortions were reported. No fertility treatment was necessary. Cytogenetic analysis from the affected son showed a reciprocal translocation t(4;10) with additional chromosomal material inserted between the translocation junctions in the derivative chromosome 10. The father showed the same derivative chromosome 10 but had additionally one aberrant chromosome 14. Further molecular cytogenetic analyses determined the inserted material in the aberrant chromosome 10 as derived from chromosome 14 and revealed a small translocation with material of chromosome 4 inserted into the derivative chromosome 14. Thus the phenotype of the son is supposed to be associated with a partial duplication 14q13-->q24.1 and a partial monosomy 4q27-->q28. Including our case we are aware of eleven CCR cases with fertile male carriers. In eight of these families normal offspring have been reported. We propose that exceptional CCRs in fertile male carriers might form comparatively simple pachytene configurations increasing the chance of healthy offspring.

Growth hormone (GH), insulin-like growth factors (IGFs), and IGF-binding protein-3 (IGFBP-3) in a child with Proteus syndrome.

Proteus syndrome is a congenital hamartomatous disorder characterized by partial overgrowth involving all germ layers. A somatic mutation model has been proposed since familial cases are extremely rare. We report on a 3-year-old girl with typical manifestations of Proteus syndrome, including local, asymmetric hypertrophy of various parts of the body. Total body length was reduced. Serum levels of IGF-I and especially IGF-II and their major growth hormone dependent binding protein (IGFBP-3) were significantly reduced, although growth hormone secretion after a pharmacological stimulus was normal. In vitro studies of fibroblasts derived from hypertrophied tissue showed normal IGF-I production and somewhat reduced IGF-II and IGFBP-3 production as compared to normal human skin fibroblasts. Affinity cross-linking experiments showed that fibroblasts of the affect tissue in Proteus syndrome produced an unusual pattern of IGF bindings proteins containing large amounts of an IGFBP with high affinity to IGF-II. The data suggest that IGF production is generally disturbed in Proteus syndrome with imbalanced levels of specific IGFBP in affected tissue.

Insect-based BioFETs with improved signal characteristics.

Insect-based BioFETs (biologically sensitive field-effect transistors) with improved signal characteristics have been developed. These BioFETs require a specifically adapted signal interfacing between a FET as signal transducer and an intact insect antenna as biocomponent. Therefore, different field-effect transistors have been fabricated in order to study the signal transfer at the bioelectronic interface. As relevant features of the BioFET, its current-voltage characteristics, the transconductance and the signal-to-noise ratio have been investigated as affected by the choice of gate insulator materials and gate dimensions (width-to-length ratio, thickness of the dielectric layers). The performance of the improved FET arrangement in the isolated-antenna BioFET was validated by employing dilution series of the plant odour component Z-3-hexen-1-ol.

Comparative study of transcranial color duplex sonography and transcranial Doppler sonography in adults.

To determine whether the frequency shift recorded in basal cerebral arteries corresponds to "true" flow velocities, a prospective comparative study of transcranial color duplex sonography (TCCD) and transcranial Doppler sonography (TCD) was performed. A 2.0-MHz transducer of a computerized TCCD system and a TCD device were used. The middle cerebral artery (MCA) and anterior cerebral artery (ACA) were examined by TCCD in 49 healthy volunteers (mean age 35 +/- 12 years). In 45 of the same volunteers a comparative TCD examination was possible. The studies were carried out blindly by different examiners at separate appointments. Peak systolic flow velocity, end-diastolic maximum flow velocity, time-averaged maximum flow velocity, and the pulsatility index were measured by both techniques. Additionally, for TCCD, time-averaged flow velocity was assessed, the resistance index and a spectral broadening index were calculated, and the energy output required for reliable measurement was analyzed. The TCCD signals were recorded in 98% of both MCA's and ACA's; with TCD, signals were recorded in 98% of MCA's and 87% of ACA's. Although in both vessels the angle-corrected peak systolic and time-averaged maximum velocities were approximately 10% to 15% higher in TCCD than in TCD measurements, correlation of flow velocities between both techniques was significant (p < 0.0001); differences between sides and age-dependency of flow velocities corresponded as well. In a reproducibility study, TCCD was repeated in 27 subjects by a third examiner with significant correlation (p < 0.0001) of both TCCD examinations. It is concluded that the advantage of TCCD is associated more with a qualitative aspect than a quantitative one. The additional visual dimension of TCCD can open new diagnostic possibilities in cerebrovascular disorders.

The development of hemodynamics in the extracranial carotid and vertebral arteries.

To investigate the development of hemodynamics in the extracranial carotid and vertebral artery system, a prospective color duplex sonography study was performed in 94 healthy children and adolescents between 3 and 18 y old. Angle-corrected flow velocities and luminal diameters were measured; waveform parameters and flow volumes were calculated. Side-to-side differences of volumetric data were analyzed. In 53 children, an intrasession test-retest flowmetry of the internal carotid and vertebral arteries was performed. From 3 to 18 y old, flow volumes decreased significantly in the vertebral arteries (p < or = 0.01) and increased in the external carotid artery (p < or = 0.0001); the luminal diameter increased in all the carotid arteries (p < or = 0.0001) and remained constant in the vertebral arteries; mean flow velocities declined in the common and internal carotid arteries and in the vertebral arteries (p < or = 0.0001), but increased in the external carotid arteries (p < or = 0.01). Flow volume rate was lower in the right than the left vertebral artery (p < or = 0.0001), and there was no side difference in any of the carotid arteries. The test-retest correlation of volumetric data was high (0.81 < or = r < or = 0.97; p < or = 0.0001). By comparing the reference data presented here with analogous adult data, we were able to delineate the physiologic development of extracranial and cerebral hemodynamics from childhood to adulthood. These data make possible the clinical application of quantitative flowmetry in extracranial cerebral arteries of children and adolescents.

Flow velocity and flow volume measurements in the extracranial carotid and vertebral arteries in healthy adults: reference data and the effects of age.

To establish reference data and to investigate the development of haemodynamics in the extracranial carotid and vertebral arteries, we performed a prospective study in 78 age- and gender-matched healthy adults from 20 to 85 y old. Angle-corrected flow velocities and luminal diameters were measured and waveform parameters and flow volumes calculated in all the arteries. Side-to-side differences and the influence of age on these parameters were also investigated. In the common carotid arteries, the internal carotid arteries and the vertebral arteries (CCA, ICA and VA, respectively) all flow velocities decreased significantly during ageing. The luminal diameter remained constant in all the carotid arteries, but increased slightly with age in the VA. An age-related decline of intravascular flow volume was observed in the ICA. Due to a pronounced decrease in end-diastolic flow velocity, the resistance index decreased in ICA and VA during ageing. There were no significant side-to-side differences in flow velocities and flow volumes in any of the extracranial arteries. The luminal diameters of the CCA, ICA and ECA were significantly smaller in women than in men. No relevant gender-related differences in flow velocities or waveform parameters were found in the extracranial arteries. There was no gender-linked difference in the flow volumes of the brain-feeding arteries and, in the ECA, flow volumes were significantly higher in men. Reference data on all flow velocities and waveform parameters, luminal diameters and flow volumes were established for different age groups between 20 and 85 y old. These data allow us to outline the development of cerebral haemodynamics during "benign ageing" and to utilise flow volume measurements in clinical practice, especially in patients with cerebrovascular diseases.

Chip-based amperometric enzyme sensor system for monitoring of bioprocesses by flow-injection analysis.

A microfluidic chip integrating amperometric enzyme sensors for the detection of glucose, glutamate and glutamine in cell-culture fermentation processes has been developed. The enzymes glucose oxidase, glutamate oxidase and glutaminase were immobilized by means of cross-linking with glutaraldehyde on platinum thin-film electrodes integrated within a microfluidic channel. The biosensor chip was coupled to a flow-injection analysis system for electrochemical characterization of the sensors. The sensors have been characterized in terms of sensitivity, linear working range and detection limit. The sensitivity evaluated from the respective peak areas was 1.47, 3.68 and 0.28 µAs/mM for the glucose, glutamate and glutamine sensor, respectively. The calibration curves were linear up to a concentration of 20 mM glucose and glutamine and up to 10 mM for glutamate. The lower detection limit amounted to be 0.05 mM for the glucose and glutamate sensor, respectively, and 0.1 mM for the glutamine sensor. Experiments in cell-culture medium have demonstrated a good correlation between the glutamate, glutamine and glucose concentrations measured with the chip-based biosensors in a differential-mode and the commercially available instrumentation. The obtained results demonstrate the feasibility of the realized microfluidic biosensor chip for monitoring of bioprocesses.