Blood phenylalanine estimation for the patient with phenylketonuria using a portable device

A simple and reliable method is described which is suitable for estimation of a whole blood phenylalanine concentration for the patient with PKU in various settings including the physician's office and the home. Excellent correlations were obtained between this method and weighed phenylalanine standards, as well as with measurement of phenylalanine in serum, plasma, and whole blood, using the McCaman-Robins fluorometric assay. Increasing the frequency and rapidity of feedback to the patient should improve metabolic control, just as home glucose monitoring has for the patient with diabetes mellitus. This method is immediately adaptable to monitoring patients with tyrosinemia, and with substitution of the appropriate amino acid ammonia lyase could be used for other amino acidemias.     

A portable device for measuring donor corneal transparency in eye banks

To develop a portable device for measuring the donor corneal transparency and validate its efficacy for corneal evaluation in the eye-banks and for research. The transparency device (TD) has a light source, a detachable system for corneal insertion and a base for light transmission. The probe detects the transmitted light which is measured by a lux-meter. A contact lens was set as ‘control’ to reduce the light scattering concern, an empty petri-plate as ‘blank’ and the cornea as ‘sample’. Two experts and non-experts (masked) observed the corneas for subjective analysis which was then compared using the TD. The parameters observed were scars, foreign-body, stromal-deformities, folds, thickness and opacity which were then converted to a relative overall percentage by the observer. Twenty corneas were evaluated for correlation, five tissues to obtain standard-deviation and twenty-four pairs for a comparative study. Experts mimicked the eye-banks with long-term experience while non-experts mimicked the emerging eye-banks. Subjective values by the experts closely resembled the measurements by TD. The average correlation between the experts and the non-experts to TD was 0.985 and 0.960 respectively. TD showed higher reproducibility than experts followed by the non-experts. The comparative study showed that increase in thickness reduces the transparency. TD is portable, easy, efficient, maintains sterility and less expensive hence the emerging eye-banks and researchers can use to raise their standards and evaluate the transparency for in vitro tests and comparative studies. The suitable transparency for the cornea deemed for clinical applications was found to be >75 %.     

Sexual dimorphism and growth hormone regulation of a hybrid gene in transgenic mice.

The sexually dimorphic expression of the urinary protein genes of mice (Mup genes) in the liver is mediated by the different male and female temporal patterns of circulating GH. Normal females were induced to male levels when GH was administered by injection to mimic the male GH pattern, showing that expression at the male level does not require a male sex steroid status in addition to intermittent GH. Two Mup-alpha 2u-globulin hybrid transgenes with different Mup gene promoters showed sexually dimorphic expression, and their expression in females increased to male levels upon testosterone treatment. GH-deficient (lit/lit) mice did not express these transgenes, and GH-deficient females did not respond to testosterone treatment, showing that GH was required for induction. Both normal and GH-deficient females were induced to male levels when GH was administered by injection. This is the first report of a transgene responsive to GH. A transgene consisting of a Mup promoter fused to a Herpes simplex virus thymidine kinase reporter sequence also showed sexual dimorphism, although to a lesser degree. It was expressed at the same level in normal females and GH-deficient mice of both sexes and was induced when GH-deficient mice were treated with GH. We propose that this transgene has a basal constitutive expression, possibly due to the absence of any rodent DNA downstream of the promoter. Since expression of the transgene was significantly induced by GH, the GH response is due at least in part to sequences in the promoter region.     

Evaluation of a portable light device for phase advancing the circadian rhythm in the home environment

This study evaluated the effectiveness of a head-mounted portable light device, Re-Timer, for phase advancing the circadian rhythm of healthy sleepers in the home environment. The Re-Timer was designed to address the limitations of traditional bright light boxes, making it more practical and efficient for administering light therapy. Eighteen healthy participants underwent a crossover design treatment protocol, consisting of seven consecutive mornings of using Re-Timer compared with the same procedure but not using Re-Timer. Circadian phase was measured using salivary dim light melatonin onset (DLMO) and subjective sleepiness was also assessed for other phase-change effects. After using the Re-Timer for seven mornings, a significant phase advance in DLMO of 41 min compared to a 10-min delay in the no-light control condition was observed. However, subjective sleepiness did not differ significantly between the two conditions. A few minor and transient side effects were experienced by participants, but no treatment was required. The Re-Timer is an effective and safe device for advancing the circadian rhythm of healthy sleepers at home. Future research on its clinical utility could make Re-Timer a practical and affordable way to self-administer bright light therapy for sleep disorders.

     

Validation of a portable EMG device to assess muscle activity during free-living situations

Portable amplifiers that record electromyograms (EMGs) for longer than four hours are commonly priced over $20,000 USD. This cost, and the technical challenges associated with recording EMGs during free-living situations, typically restrict EMG use to laboratory settings. A low-cost system (μEMG; OT Bioelecttronica, 100€), using specialized concentric bipolar electrodes, has been developed specifically for free-living situations. The purpose of this study was to validate the μEMG system by comparing EMGs from μEMG with a laboratory-based alternative (Telemyo 900; Noraxon USA, Inc.). Surface EMGs from biceps brachii (BB) and tibialis anterior (TA) of ten subjects were recorded simultaneously with both systems as subjects performed maximal voluntary contractions (MVCs), submaximal contractions at 25%, 50%, and 75% MVC, seven simulated activities of daily living (ADLs), and >60 min of simulated free-living inside the laboratory. In general, EMG parameters (e.g., average full-wave rectified EMG amplitude) derived from both systems were not significantly different for all outcome variables, except there were small differences across systems in baseline noise and absolute EMG amplitudes during MVCs. These results suggest that μEMG is a valid approach to the long-term recording of EMG.     

Growth hormone gene regulation: a paradigm for cell-type-specific gene activation

The growth hormone (GH) gene is specifically expressed within specialized cells of the anterior pituitary. The central role in GH gene activation is played by GHF-1, a homeodomain protein that is itself specifically expressed in the anterior pituitary.     

HaploSearch: a tool for haplotype-sequence two-way transformation

Comparison of available mitochondrial DNA data is some times hindered by the data presentation format. HaploSearch is a simple tool for transforming DNA sequences into haplotype data and vice versa, speeding up the manipulation of large datasets. Although designed for mitochondrial DNA, HaploSearch could be used with any kind of DNA type. HaploSearch program, detailed software instructions and example files are freely available on the web http://www.haplosite.com/haplosearch/.     

Parallel gene synthesis in a microfluidic device

The ability to synthesize custom de novo DNA constructs rapidly, accurately and inexpensively is highly desired by researchers, as synthetic genes and longer DNA constructs are enabling to numerous powerful applications in both traditional molecular biology and the emerging field of synthetic biology. However, the current cost of de novo synthesis—driven largely by reagent and handling costs—is a significant barrier to the widespread availability of such technology. In this work, we demonstrate, to our knowledge, the first gene synthesis in a microfluidic environment. The use of microfluidic technology greatly reduces reaction volumes and the corresponding reagent and handling costs. Additionally, microfluidic technology enables large numbers of complex reactions to be performed in parallel. Here, we report the fabrication of a multi-chamber microfluidic device and its use in carrying out the syntheses of several DNA constructs. Genes up to 1kb in length were synthesized in parallel at minute starting oligonucleotide concentrations (10–25nM) in four 500nl reactors. Such volumes are one to two orders of magnitude lower than those utilized in conventional gene synthesis. The identity of all target genes was verified by sequencing, and the resultant error rate was determined to be 1 per 560 bases.     

Discovering gene networks with a neural-genetic hybrid

Recent advances in biology (namely, DNA arrays) allow an unprecedented view of the biochemical mechanisms contained within a cell. However, this technology raises new challenges for computer scientists and biologists alike, as the data created by these arrays is often highly complex. One of the challenges is the elucidation of the regulatory connections and interactions between genes, proteins and other gene products. In this paper, a novel method is described for determining gene interactions in temporal gene expression data using genetic algorithms combined with a neural network component. Experiments conducted on real-world temporal gene expression data sets confirm that the approach is capable of finding gene networks that fit the data. A further repeated approach shows that those genes significantly involved in interaction with other genes can be highlighted and hypothetical gene networks and circuits proposed for further laboratory testing.     

Comparison of video recording and a portable electronic device for measuring the feeding behaviour of individually housed dairy goats

A detailed knowledge of chewing behaviour is important in understanding the factors that can affect digestive function in high producing ruminants. The aim of this study was to compare chewing behaviour either measured with a portable automatic system (APEC) which records jaw movements or obtained by scan sampling video analysis in 12 individually housed dairy goats. One hour and daily time-intervals were used for the analysis. APEC and video showed better agreement for 1 h than for daily time-intervals but a very high individual variability was observed for all the parameters measured. Daily duration of rumination seemed to be assessed better by the APEC than by the video because it is sometimes difficult to determine if the goats are resting or ruminating on the video. Daily duration of intake was however assessed better by the video because the automatic recorder interpreted all oral behaviours as intake. However, total chewing time is directly related to the amount of saliva produced which an important factor in ruminant nutrition. The APEC allows continuous recording of activity independently of the animal's position in the pen or in a group or at pasture where animals cannot be filmed, however the device can be easily damaged by the animals. Video cannot be damaged by the animals but it can be difficult to determine the animal's activity if the animal is lying-down or not facing the camera, or in a dark part of its pen. Both systems were relevant to measure chewing behaviour of stall housed dairy goats, and to study the daily time-budget of feeding behaviour but results have to be interpreted carefully.     

A portable system for collecting anatomical joint angles during stair ascent: a comparison with an optical tracking device

Background

Assessments of stair climbing in real-life situations using an optical tracking system are lacking, as it is difficult to adapt the system for use in and around full flights of stairs. Alternatively, a portable system that consists of inertial measurement units (IMUs) can be used to collect anatomical joint angles during stair ascent. The purpose of this study was to compare the anatomical joint angles obtained by IMUs to those calculated from position data of an optical tracking device.

Methods

Anatomical joint angles of the thigh, knee and ankle, obtained using IMUs and an optical tracking device, were compared for fourteen healthy subjects. Joint kinematics obtained with the two measurement devices were evaluated by calculating the root mean square error (RMSE) and by calculating a two-tailed Pearson product-moment correlation coefficient (r) between the two signals.

Results

Strong mean correlations (range 0.93 to 0.99) were found for the angles between the two measurement devices, as well as an average root mean square error (RMSE) of 4 degrees over all the joint angles, showing that the IMUs are a satisfactory system for measuring anatomical joint angles.

Conclusion

These highly portable body-worn inertial sensors can be used by clinicians and researchers alike, to accurately collect data during stair climbing in complex real-life situations.

     

Validation of portable muscle tone measurement device for quantifying velocity-dependent properties in elbow spasticity.

The objective of this study is to develop a portable device for quantifying the velocity-dependent properties of spastic elbow muscles. Based on a motor-driven system, validation tests of the portable system such as accuracy and response of sensors were first examined. Furthermore, simulated modules (inertia, damper and spring) as well as elbow joints (15 control and 15 hemiplegic subjects) were manually stretched under four different frequencies (1/3, 1/2, 1 and 3/2 Hz) through 60 degrees range of motion. Joint resistance and displacement during sinusoidal stretch were collected for further analysis. Two quantitative parameters (i.e., viscous components under each frequency and averaged viscosity across four frequencies) were derived to estimate the velocity-dependent properties of elbow joint. Tests of simulated modules confirm the manual stretch protocol and data analysis are valid in estimating the velocity-dependent component during a sinusoidal stretch. Compared to normal control, viscous component in each stretch frequency and averaged viscosity were significantly higher in subjects with spasticity (P < 0.001). The viscous component and averaged viscosity were found highly correlated with the modified Ashworth scale. These findings suggest that measurements of viscous component and averaged viscosity during manual sinusoidal stretching using the portable device could be clinically useful in evaluating spasticity.     

Engineering monovalent quantum dot-antibody bioconjugates with a hybrid gel system

Monovalent nanoparticles are of strong current interest in biological imaging and detection due to their potential for stoichiometric binding with target molecules. We report the preparation of monovalent quantum dot-antibody bioconjugates using a high-resolution hybrid gel system specially designed for fractionation of nanoparticle bioconjugates. A key feature of this technology is that it is broadly applicable to many types of nanoparticle-antibody complexes without the need of genetically engineered proteins. This is particularly important because antibodies are still the dominant molecular targeting probes, despite new discoveries made with other targeting probes such as aptamers and peptides. Furthermore, we show experimental evidence of improved quantification capability using the monovalent probes, whose advantages over their multivalent counterparts had largely been a theoretic prediction previously. This new class of nanoprobe should find broad application in quantitative biological detection and imaging in vitro and in vivo.