Heart rate variability and baroreflex sensitivity in hypertensive subjects with and without metabolic features of insulin resistance syndrome

PURPOSE: The traditional approach to investigating suspected osteomyelitis in children includes conventional radiography and bone scintigraphy. The roles of US, CT and MR imaging are controversial. Our objective was to determine whether the additional use of these modalities would yield information likely to lead to treatment modification. MATERIAL AND METHODS: Sixty-five children with clinically suspected osteomyelitis took part in a prospective study. All patients underwent conventional radiography and bone scintigraphy. In addition to this, US, CT and MR imaging were all performed in 33 patients; the remaining 32 patients were examined with various combinations of these three modalities. The value of the additional information obtained was estimated retrospectively by a pediatric orthopedic surgeon in terms of possible modification of treatment. RESULTS: MR imaging was the modality with the highest sensitivity and specificity for detecting osteomyelitis. MR yielded information likely to influence treatment in the greatest proportion of patients (45%) followed by US (30%). CONCLUSION: The standard investigation protocol with the addition of US (because of its ability to detect subperiosteal abscesses early and simply) is adequate in uncomplicated cases. When additional imaging is required to outline a lesion, or in complicated cases, and when bone scintigraphy is inconclusive, MR imaging should also be performed. CT should be considered when MR investigation is not available or when anesthesia is required but cannot be provided.     

Cholinergic-induced production of reactive oxygen species in human neuroblastoma cells

Stimulation of human SH-SY5Y neuroblastoma cells by a muscarinic receptor agonist, carbachol (CCh; 1 mM), elevated levels of free intracellular calcium and subsequently increased the production of reactive oxygen species (ROS). Quinuclidinylbenzilate (QNB) binding increased at 1 h after CCh, but returned back to the control level at 3 h. Production of ROS increased, however, during the 3 h time period. CCh also increased the translocation of protein kinase C (PKC) to the membrane. ROS production was completely blocked by atropine and a PKC inhibitor, Ro 31-8220. These results show that increased ROS production was a result of muscarinic receptor stimulation, and that PKC had an active role in this cellular stimulation. ROS production upon cellular stimulation by CCh was completely inhibited also by superoxide dismutase, and partially by catalase, indicating that the formation of superoxide anion dominated in cholinergic-induced generation of ROS in human neuroblastoma cells. These results also show that muscarinic stimulation causes sustained ROS production in human neuroblastoma cells. The slow increase in ROS production by CCh suggest a stepwise cascade of events leading to oxidative stress with a triggering role of cholinergic muscarinic receptors in this process.     

Monolithic super-bright red resonant cavity light-emitting diodegrown by solid source molecular beam epitaxy

Monolithic super-bright resonant-cavity light-emitting diode operating at λ=663 nm has been developed. The diode consisted of a 1λ-thick AlGaInP active region sandwiched between AlAs-AlGaAs distributed Bragg reflectors. The device structure was grown by solid source molecular beam epitaxy. The current aperture of the emitter was created by lateral selective wet thermal oxidation. A record-high peak wall-plug efficiency of 2.2% and a continuous-wave output power of 1.4 mW were attained without heatsinking at room temperature from a diode having a diameter of 80 μm. The emission linewidth was as narrow as 4.5 nm     

Contextual clustering for analysis of functional MRI data

We present a contextual clustering procedure for statistical parametric maps (SPM) calculated from time varying three-dimensional images. The algorithm can be used for the detection of neural activations from functional magnetic resonance images (fMRI). An important characteristic of SPM is that the intensity distribution of background (nonactive area) is known whereas the distributions of activation areas are not. The developed contextual clustering algorithm divides an SPM into background and activation areas so that the probability of detecting false activations by chance is controlled, i.e., hypothesis testing is performed. Unlike the much used voxel-by-voxel testing, neighborhood information is utilized, an important difference. This is achieved by using a Markov random field prior and iterated conditional modes (ICM) algorithm. However, unlike in the conventional use of ICM algorithm, the classification is based only on the distribution of background. The results from our simulations and human fMRI experiments using visual stimulation demonstrate that a better sensitivity is achieved with a given specificity in comparison to the voxel-by-voxel thresholding technique. The algorithm is computationally efficient and can be used to detect and delineate objects from a noisy background in other applications.     

The stability properties of golden beet and red beet pigments: influence of pH, temperature, and some stabilizers.

Golden beet (Beta vulgaris var. lutea) color was found to contain 8 components, of which the most important seemed to be vulgaxanthin-I and -II. Purified vulgazanthin -I solutions are easily degraded at high temperatures. The stability is, however, strongly dependent on pH: the stability is best at pH values between 5 and 6, the poorest at low pH values, but at pH 7 the stability is better than that of betanin. Vulgaxanthin-I is more stable in the raw extract than in a purified solution. EDTA, even in ppm amounts, was found to improve the stability of betanin. The effect was dependent on pH value, being most efficient at pH 2.0 and 5.0. Stability of vulgaxanthin-I was not improved by EDTA. Tannin did not show stabilizing influence. Ascorbic acid was found to have an unfavorable influence on stability, especially in the case of betanin.