Functioning of families with primary school-age children conceived using anonymous donor sperm.

STUDY QUESTION: How do families with children conceived using donor sperm operate as the children grow up? SUMMARY ANSWER: Families with children aged 5-13 years conceived through anonymous donor sperm function well, when compared with other family types with children of the same developmental stage. WHAT IS KNOWN ALREADY: Previous studies on family relationships after donor sperm conception have been reassuring. However, these studies have suffered from methodological limitations due to small sample sizes, respondent biases and absence of appropriate controls. STUDY DESIGN, SIZE, DURATION: This study was an observational study comparing 79 'donor insemination' (DI) families with 987 'couple' families, 364 'single mother' and 112 'step-father' families as part of the Australian Institute of Family Studies Children and Family Life (CFL) study. CFL involved the collection of data on family functioning and child wellbeing from all resident parents through a Family and Child Questionnaire for the 'primary' parent (FACQ-P1) and a Family Relationship Questionnaire (FRQ-P2) for the 'other' parent. PARTICIPANTS/MATERIALS, SETTING, METHODS: All questionnaires were coded with the identity known only to the researchers. The outcomes studied included parent psychological adjustment, family functioning, couple relationship, parenting and parent-child relationship. Family types were compared, separately for mothers' and fathers' reports. The results presented are the estimated means for each family type based on the final model for each outcome: post hoc comparisons between family types are reported with 95% confidence limits. MAIN RESULTS AND THE ROLE OF CHANCE: With all of the outcomes considered, there was not one result where the DI families showed poorer functioning on average than the comparison groups. LIMITATIONS, REASON FOR CAUTION: The final sample size of DI families is 79 with an excellent response rate of nearly 80%. However, there remains some scope for response bias. WIDER IMPLICATIONS OF THE FINDINGS: This study further reassures us that families conceived with anonymous donor sperm do not function any differently from other family types.

Non-invasive cardiac output trending during exercise recovery on a bathroom-scale-based ballistocardiograph.

Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R(2) = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland-Altman methods for assessing agreement, the mean bias was found to be -0.5% (+/-24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional.

Robust ballistocardiogram acquisition for home monitoring.

The ballistocardiogram (BCG) measures the reaction of the body to cardiac ejection forces, and is an effective, non-invasive means of evaluating cardiovascular function. A simple, robust method is presented for acquiring high-quality, repeatable BCG signals from a modified, commercially available scale. The measured BCG waveforms for all subjects qualitatively matched values in the existing literature and physiologic expectations in terms of timing and IJ amplitude. Additionally, the BCG IJ amplitude was shown to be correlated with diastolic filling time for a subject with premature atrial contractions, demonstrating the sensitivity of the apparatus to beat-by-beat hemodynamic changes. The signal-to-noise ratio (SNR) of the BCG was estimated using two methods, and the average SNR over all subjects was greater than 12 for both estimates. The BCG measurement was shown to be repeatable over 50 recordings taken from the same subject over a three week period. This approach could allow patients at home to monitor trends in cardiovascular health.

Synergistic interaction of ABCB1 and ABCG2 polymorphisms predicts the prevalence of toxic encephalopathy during anticancer chemotherapy.

Polymorphisms of the ABCB1 (MDR1) and ABCG2 (BCRP) genes were reported to alter the expression and function of these drug transporters. Both proteins are present at the main pharmacokinetic barriers including the blood-brain barrier. Data from 291 children with acute lymphoblastic leukaemia were analysed in this retrospective study. ABCB1 3435T>C, 2677G>T/A, 1236C>T and ABCG2 421C>A, 34G>A genotypes were determined. Encephalopathy episodes were more frequent among those with ABCB1 3435TT genotype than in the 3435CC/CT group (odds ratio (OR) 3.5; P=0.03). Patients with the ABCG2 421A allele tended to have more complications than wild type homozygotes (OR=2.0; P=0.25). The rate of the adverse effect was similar in those harbouring no or only one of the predisposing genotypes, that is, either ABCB1 3435TT or ABCG2 421AA/AC. However, significantly more children suffered encephalopathy in the group with both predisposing genotypes (OR=12.3; P=0.005). In conclusion, these variations exert synergistic effect in predisposing patients to toxic neurological complications of chemotherapy.

Multi-unit recording from regenerated bullfrog eighth nerve using implantable silicon-substrate microelectrodes.

Multi-microelectrode silicon devices were developed for extracellular recording from multiple axons in regenerated eighth cranial nerves of American bullfrogs. Each includes a photolithographically defined array of holes and adjacent metal microelectrodes. A device is implanted within a transected eighth nerve; regenerating fibers grow through the holes en route to the brainstem. Multiple spike trains were recorded from two animals at up to 21 weeks after implantation. Single units were tracked for over 8 h. Some responded to sound with tuning typical of fibers innervating the amphibian and basilar papillae. Units of vestibular origin also were recorded. Action potentials were 30-140 microV P-P amid noise of 5 10 microV RMS, an adequate signal-to-noise ratio for spike detection and sorting. Histology confirmed that bundles of myelinated fibers grew through holes near electrodes that recorded activity. The implantation success rate was low, due to surgical morbidity, device extrusion, and lack of nerve regeneration through some devices. Future designs will address these issues and incorporate transistor amplifiers on devices to increase signal-to-noise ratios. The potential of implanted silicon devices to simultaneously record from many axons offers an opportunity for multicellular studies of auditor, vestibular and seismic signal processing in the vertebrate inner ear.

Microelectrode arrays for stimulation of neural slice preparations.

A planar 6 x 6 array of iridium electrodes with four reference electrodes has been developed for use with neural tissue preparations. Precise knowledge of the relative locations of the array elements allows for spatial neurophysiological analyses. The 10 microns diameter platinized iridium electrodes on a 100 microns pitch have been used to stimulate acutely prepared slices of spinal cord from free-ranging rodents. An intracellular recording from a single neuron in the substantia gelatinosa (SG) using the whole-cell, tight-seal technique allowed low noise, high resolution studies of excitatory or inhibitory electrical responses of a given neuron to inputs from the primary afferent fibers or from stimulation by individual electrodes of the array. The resulting maps of responses provide an indication of the interconnectivity of neural processes. The pattern emerging is that of limited interconnectivity in the SG from areas surrounding a recorded neuron but with strong excitatory or inhibitory effects from those oriented in a longitudinal (rostral-caudal) direction relative to the neuron. The observations to date suggest the neurons of the SG are arranged in sets of independent networks, possibly related to sensory modality and input from particular body regions.

A feedback controlled silicon microprobe for quantitative mechanical stimulation of nerve and tissue.

The ability to apply and control the force and force velocity of mechanical stimulation is essential for the study of mechanoelectric transduction and adaptation processes. Silicon micromachining technology was used to produce miniature (20-70 microns wide) mechanical microprobes. Passive polysilicon, piezoresistive, force sensing elements were deposited onto the boron-doped epitaxial silicon and the individual devices were chemically etched from the bulk wafer. These microprobes display a linear force versus output voltage relationship. Stimulation forces up to 2 mN can be generated with a measurement resolution of 1.5 microN. The probes were mounted onto circuit board holders and their output sent to a proportional-integral controller which drives an electromagnetic actuator. By using this force-feedback control circuit coupled to a PC it is possible to define any stimulus wave form pattern and independently control and measure the actual stimulus force and velocity. A computer controlled 3-axis stepper motor (0.025 micron step capability) manipulator is used to position the silicon microprobe-actuator assembly relative to the mechanoreceptive field. Sensor feedback control coupled to the 3-axis stepper motor manipulator allows automatic touchdown control and/or preloading of the probe prior to stimulation. Three-dimensional topographic manipulator feedback position control allows automated receptive field mapping.

Portable cell-based biosensor system using integrated CMOS cell-cartridges.

The use of cell-based biosensors outside of the laboratory has been limited due to many issues including preparation of the sample, maintenance of the biological environment, and integration of the electronics for data collection and analysis. This paper describes a system that addresses several of these issues with the development of an integrated silicon-polydimethylsiloxane cell-cartridge. The cell-cartridge contains a CMOS silicon chip that incorporates a digital interface, temperature control system, microelectrode electrophysiology sensors, and analog signal buffering. Additionally, the cell-cartridge supports two separate cell populations in two 10 microl sealed chambers that have independent fluidic channels for sample injection. A portable, microcontroller-based electronics system capable of monitoring the action potential (AP) activity within the cell-cartridges was also developed. The AP activities of cardiomyocyte syncytia in the two chambers differentially responded to the flow of a control medium versus the flow of a biochemical agent. The cell-cartridges and portable electronics system were used to successfully record AP activity from cardiomyocytes outside of the laboratory under realistic application conditions.

General purpose, field-portable cell-based biosensor platform.

There are several groups of researchers developing cell-based biosensors for chemical and biological warfare agents based on electrophysiologic monitoring of cells. In order to transition such sensors from the laboratory to the field, a general-purpose hardware and software platform is required. This paper describes the design, implementation, and field-testing of such a system, consisting of cell-transport and data acquisition instruments. The cell-transport module is a self-contained, battery-powered instrument that allows various types of cell-based modules to be maintained at a preset temperature and ambient CO(2) level while in transit or in the field. The data acquisition module provides 32 channels of action potential amplification, filtering, and real-time data streaming to a laptop computer. At present, detailed analysis of the data acquired is carried out off-line, but sufficient computing power is available in the data acquisition module to enable the most useful algorithms to eventually be run real-time in the field. Both modules have sufficient internal power to permit realistic field-testing, such as the example presented in this paper.