Early gamma-oscillations as correlate of localized nociceptive processing in primary sensorimotor cortex.

Recent studies put forward the idea that stimulus-evoked gamma-band oscillations (GBOs; 30-100 Hz) play a specific role in nociception. So far, evidence for the specificity of GBOs for nociception, their possible involvement in nociceptive sensory discriminatory abilities, and knowledge regarding their cortical sources is just starting to grow. To address these questions, we used electroencephalography (EEG) to record brain activity evoked by phasic nociceptive laser stimuli and tactile stimuli applied at different intensities to the right hand and foot of 12 healthy volunteers. The EEG was analyzed in the time domain to extract phase-locked event-related brain potentials (ERPs) and in three regions of interest in the time-frequency domain (delta/theta, 40-Hz gamma, 70-Hz gamma) to extract stimulus-evoked changes in the magnitude of non-phase-locked brain oscillations. Both nociceptive and tactile stimuli, matched with respect to subjective intensity, elicited phase locked ERPs of increasing amplitude with increasing stimulus intensity. In contrast, only nociceptive stimuli elicited a significant enhancement of GBOs (65-85 Hz, 150-230 ms after stimulus onset), whose magnitude encoded stimulus intensity, whereas tactile stimuli led to a GBO decrease. Following nociceptive hand stimulation, the topographical distribution of GBOs was maximal at contralateral electrode C3, whereas maximum activity following foot stimulation was recorded at the midline electrode Cz, compatible with generation of GBOs in the representations of the hand and foot of the primary sensorimotor cortex, respectively. The differential behavior of high-frequency GBOs and low-frequency 40-Hz GBOs is indicating different functional roles and regions in sensory processing.NEW & NOTEWORTHY Gamma-band oscillations show hand-foot somatotopy compatible with generation in primary sensorimotor cortex and are present following nociceptive but not tactile stimulation of the hand and foot in humans.

Integral steric asymmetry in the inelastic scattering of NO(X2Π).

The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O2 system is also presented. Close-coupled quantum mechanical scattering calculations employing well-tested ab initio potential energy surfaces were able to reproduce the steric asymmetry observed for the NO-rare gas systems. Quantum mechanical scattering and quasi-classical trajectory calculations were further used to help interpret the integral steric asymmetry for NO + O2. Whilst the main features of the integral steric asymmetry of NO with the rare gases are also observed for the O2 collision partner, some subtle differences provide insight into the form of the underlying potentials for the more complex system.

Biophysical parameters modification could overcome essential hearing gaps.

A majority of hearing defects are due to malfunction of the outer hair cells (OHCs), those cells within the mammalian hearing sensor (the cochlea) that provide an active amplification of the incoming signal. Malformation of the hearing sensor, ototoxic drugs, acoustical trauma, infections, or the effect of aging affect often a whole frequency interval, which leads to a substantial loss of speech intelligibility. Using an energy-based biophysical model of the passive cochlea, we obtain an explicit description of the dependence of the tonotopic map on the biophysical parameters of the cochlea. Our findings indicate the possibility that by suitable local modifications of the biophysical parameters by microsurgery, even very salient gaps of the tonotopic map could be bridged.

Three-dimensional color holographic display.

Three-dimensional (3D) color holograms are recorded in a cerium-doped, strontium barium niobate (SBN:60) photorefractive crystal. These holograms are shown to reconstruct true color reproductions of the original object with an observable field of view of 37 degrees. Angle multiplexing of two or more 3D color holograms is also demonstrated with angle tuning of the reference beam corresponding to a separation angle between stored images of 0.082 degrees. Each of these results is compared with corresponding theoretical predictions.

Thrombopoietin levels in patients with cirrhosis before and after orthotopic liver transplantation.

BACKGROUND: Thrombocytopenia is a common manifestation of cirrhosis. OBJECTIVES: To determine plasma thrombopoietin levels in cirrhotic patients with thrombocytopenia, monitor those levels before and after orthotopic liver transplantation, and compare thrombopoietin messenger RNA (mRNA) levels in liver samples from cirrhotic patients and controls. DESIGN: A cross-sectional study of patients with cirrhosis, including a small subset of patients who had orthotopic liver transplantation. SETTING: University-affiliated hospital. PATIENTS: 44 patients with cirrhosis, including 17 patients who had orthotopic liver transplantation. INTERVENTION: Orthotopic liver transplantation. MEASUREMENTS: Plasma thrombopoietin levels in all patients, platelet counts in all patients, and thrombopoietin mRNA levels in liver samples from nine patients with cirrhosis and eight controls. RESULTS: Thrombopoietin levels were undetectable in 39 of 44 patients with cirrhosis. In 16 of 17 patients, the levels became detectable after liver transplantation. Thrombopoietin mRNA levels were decreased in liver samples from patients with cirrhosis compared with controls (P = 0.0103). CONCLUSIONS: The low thrombopoietin levels in cirrhotic patients with thrombocytopenia and the increased levels after orthotopic liver transplantation suggest that impaired production of thrombopoietin may contribute to thrombocytopenia associated with cirrhosis.

Real time quantitative PCR.

We have developed a novel "real time" quantitative PCR method. The method measures PCR product accumulation through a dual-labeled fluorogenic probe (i.e., TaqMan Probe). This method provides very accurate and reproducible quantitation of gene copies. Unlike other quantitative PCR methods, real-time PCR does not require post-PCR sample handling, preventing potential PCR product carry-over contamination and resulting in much faster and higher throughput assays. The real-time PCR method has a very large dynamic range of starting target molecule determination (at least five orders of magnitude). Real-time quantitative PCR is extremely accurate and less labor-intensive than current quantitative PCR methods.

A novel method for real time quantitative RT-PCR.

A novel approach to quantitative reverse transcriptase polymerase chain reaction (QC RT-PCR) using real time detection and the 5' nuclease assay has been developed. Cystic fibrosis transmembrane transductance regulator (CFTR) target mRNA is reverse transcribed, amplified, detected, and quantitated in real time. A fluorogenic probe was designed to detect the CFTR amplicon. Relative increase in 6-carboxy-fluorescein reporter fluorescent emission is monitored during PCR amplification using an analytical thermal cycler. An internal control template containing the same primer sequences as the CFTR amplicon, but a different internal sequence, has been designed as a control. An internal control probe with a reporter fluorescent dye tetrachloro-6-carboxy-fluorescein was designed to hybridize to the internal control amplicon. The internal control template is placed in each reaction tube and is used for quantitative analysis of the CFTR mRNA. This method provides a convenient and high-throughput format for QC RT-PCR.

Quantitative competitive polymerase chain reaction: analysis of amplified products of the HIV-1 gag gene by capillary electrophoresis with laser-induced fluorescence detection.

A quantitative competitive polymerase chain reaction (PCR) assay for the detection and quantification of HIV-1 has been developed using capillary electrophoresis. Separation of the PCR products is carried out in coated capillaries filled with replaceable linear polyacrylamide, and detection is performed using laser-induced fluorescence. The quantitative capabilities of this assay are described. We show results from analysis of a noninfectious plasmid encoding the HIV genome and integrated proviral DNA. Potential applications of this assay are discussed.

Isolation and characterization of a cosmid contig for the GCPS gene region.

The zinc finger gene GLI3 has been shown to be involved in the embryonal development of the limbs and skull. Mutations in GLI3 lead to the development of the human Greig cephalopolysyndactyly syndrome (GCPS) and the mouse mutations extra toes (Xt) and anterior digit deformity (add). The GCPS locus on human chromosome 7p13 has recently been isolated in a yeast artificial chromosome (YAC) contig. Here, we describe the establishment of a cosmid contig that was derived from two of the YAC clones, that spans 550 kb of human DNA, and that includes the GLI3 gene. In this contig, three GCPS translocation breakpoints have been mapped to distinct EcoRI fragments in the 3' half of the gene. In addition, exon-carrying fragments have been identified and the size of the GLI3 gene could be determined as at least 280 kb. The gene is flanked by a CpG island that lies on the 5' side and that is in close proximity to the first exon detected by the cloned GLI3 cDNA. Further upstream, five segments were found that have been conserved between man and mouse. In the mouse, this region has been characterized as the transgene integration site resulting in the add phenotype. Both the CpG island and the conserved regions are probable candidates for a search for GLI3 promoter and control elements.

Effect of starch malabsorption on fecal bile acids and neutral sterols in humans: possible implications for colonic carcinogenesis.

Epidemiological and experimental studies indicate a strong association between an elevated colon cancer risk and increased fecal excretion of secondary bile acids, neutral sterols, and prolonged gastrointestinal transit time. Starch malabsorption, on the other hand, has been reported to be a possible protective factor in colon carcinogenesis. To study the impact of starch malabsorption on these parameters, 12 healthy volunteers consumed a diet rich in starch for two 4-week periods. During a double-blind crossover trial they received the alpha-glucosidase inhibitor acarbose (BAY g 5421) in one of the study periods and placebo in the other. During acarbose treatment stool wet weight increased by 68%, stool dry weight by 57%, and gastrointestinal mean transit time by 30%. Fecal concentrations (mg/g dry weight) of the neutral sterols coprostanol, coprostanone, campesterol, 4-cholesten-3-one, and beta-sitosterol decreased by 36.8, 48.7, 42.1, 34.6, and 39.4%, respectively, under acarbose. Concentrations of the major secondary bile acids, deoxycholic and lithocholic acid, decreased by 59.9 and 52.2%, respectively. In spite of an increased stool weight, also daily excretion (mg/day) of these two bile acids was lower under acarbose (47.9 and 36.6%, respectively) compared to placebo, whereas excretion of the main primary bile acid, cholic acid, rose from 22.58 mg/day to 379.80 mg/day during the acarbose period. The changes in fecal bile acid and neutral sterol excretion found during acarbose treatment may explain a protective effect of starch malabsorption on colon cancer development.