Psychophysical Investigations into the Role of Low-Threshold C Fibres in Non-Painful Affective Processing and Pain Modulation

We recently showed that C low-threshold mechanoreceptors (CLTMRs) contribute to touch-evoked pain (allodynia) during experimental muscle pain. Conversely, in absence of ongoing pain, the activation of CLTMRs has been shown to correlate with a diffuse sensation of pleasant touch. In this study, we evaluated (1) the primary afferent fibre types contributing to positive (pleasant) and negative (unpleasant) affective touch and (2) the effects of tactile stimuli on tonic muscle pain by varying affective attributes and frequency parameters. Psychophysical observations were made in 10 healthy participants. Two types of test stimuli were applied: stroking stimulus using velvet or sandpaper at speeds of 0.1, 1.0 and 10.0 cm/s; focal vibrotactile stimulus at low (20 Hz) or high (200 Hz) frequency. These stimuli were applied in the normal condition (i.e. no experimental pain) and following the induction of muscle pain by infusing hypertonic saline (5%) into the tibialis anterior muscle. These observations were repeated following the conduction block of myelinated fibres by compression of sciatic nerve. In absence of muscle pain, all participants reliably linked velvet-stroking to pleasantness and sandpaper-stroking to unpleasantness (no pain). Likewise, low-frequency vibration was linked to pleasantness and high-frequency vibration to unpleasantness. During muscle pain, the application of previously pleasant stimuli resulted in overall pain relief, whereas the application of previously unpleasant stimuli resulted in overall pain intensification. These effects were significant, reproducible and persisted following the blockade of myelinated fibres. Taken together, these findings suggest the role of low-threshold C fibres in affective and pain processing. Furthermore, these observations suggest that temporal coding need not be limited to discriminative aspects of tactile processing, but may contribute to affective attributes, which in turn predispose individual responses towards excitatory or inhibitory modulation of pain.     

Synthesis of Novel Quinoline–Benzoxazolinone Ester Hybrids: In Vitro Anti-Inflammatory Activity and Antibacterial Activity

Russian Journal of Bioorganic Chemistry - A series of novel quinoline-benzoxazolinone ester hybrids were synthesized characterized and assessed for their in vitro anti-inflammatory and...     

PKC-beta1 isoform activation is required for EGF-induced NF-kappaB inactivation and IkappaBalpha stabilization and protection of F-actin assembly and barrier function in enterocyte monolayers

Using monolayers of intestinal Caco-2 cells, we reported that activation of NF-kappaB is required for oxidative disruption and that EGF protects against this injury but the mechanism remains unclear. Activation of the PKC-beta1 isoform is key to monolayer barrier integrity. We hypothesized that EGF-induced activation of PKC-beta1 prevents oxidant-induced activation of NF-kappaB and the consequences of NF-kappaB activation, F-actin, and barrier dysfunction. We used wild-type (WT) and transfected cells. The latter were transfected with varying levels of cDNA to overexpress or underexpress PKC-beta1. Cells were pretreated with EGF or PKC modulators +/- oxidant. Pretreatment with EGF protected monolayers by increasing native PKC-beta1 activity, decreasing IkappaBalpha phosphorylation/degradation, suppressing NF-kappaB activation (p50/p65 subunit nuclear translocation/activity), enhancing stable actin (increased F-actin-to-G-actin ratio), increasing stability of actin cytoskeleton, and reducing barrier hyperpermeability. Cells stably overexpressing PKC-beta1 were protected by low, previously nonprotective doses of EGF or modulators. In these clones, we found enhanced IkappaBalpha stabilization, NF-kappaB inactivation, actin stability, and barrier function. Low doses of the modulators led to increases in PKC-beta1 in the particulate fractions, indicating activation. Stably inhibiting endogenous PKC-beta1 substantially prevented all measures of EGF's protection against NF-kappaB activation. We conclude that EGF-mediated protection against oxidant disruption of the intestinal barrier function requires PKC-beta1 activation and NF-kappaB suppression. The molecular event underlying this unique effect of PKC-beta1 involves inhibition of phosphorylation and increases in stabilization of IkappaBalpha. The ability to inhibit the dynamics of NF-kappaB/IkappaBalpha and F-actin disassembly is a novel mechanism not previously attributed to the classic subfamily of PKC isoforms.     

Tuning dual emission behavior of p-dialkylaminobenzonitriles by supramolecular interactions with cyclodextrin hosts

Ground state absorption and steady-state and time-resolved fluorescence measurements have been carried out to understand the host-guest interactions of p-diethylaminobenzonitrile (DEABN) and p-dimethylaminobenzonitrile (DMABN) dyes with alpha-cyclodextrin (alpha-CD) and beta-cyclodextrin (beta-CD) hosts. DEABN and DMABN dyes show both locally excited (LE) state and intramolecular charge transfer (ICT) state emissions in solution. The LE and ICT emissions of the dyes are seen to get modulated in the presence of alpha-CD and beta-CD hosts. The results indicate that the dyes form 1 : 1 inclusion complexes with both the hosts. Comparing the binding constants and the fluorescence characteristics of different dye x CD systems it is inferred that DEABN adopts a completely different orientation on complexation with alpha-CD than in the other cases of dye.CD systems. It is indicated that while in all other cases of dye x CD systems the N,N-dialkyl group of the dyes enters the host cavity leaving the C[triple bond, length as m-dash]N group projected out into the water phase, the DEABN dye enters the alpha-CD cavity (smallest CD) with its C[triple bond, length as m-dash]N group entering the host cavity. The differences in the orientation of the dye in the host cavities is understood to be determined by the requirement of maximum van der Waals contact of the encapsulated dye with the host cavity for maximum stability of the complex and the relative sizes of the substituents of the dye compared to the host cavities. From the observation that the binding constants for the present dye x CD systems are not that significantly high, it is inferred that the hydrophobic interaction mainly govern the inclusion complex formation in the present systems.     

Greater diversity of Shiga toxin-encoding bacteriophage insertion sites among Escherichia coli O157:H7 isolates from cattle than in those from humans

Escherichia coli O157:H7, a zoonotic human pathogen for which domestic cattle are a reservoir host, produces a Shiga toxin(s) (Stx) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (clusters 1 to 3) among clinical isolates of E. coli O157:H7. Stx-encoding bacteriophage insertion site genotypes of 282 clinical and 80 bovine isolates were evaluated. A total of 268 (95.0%) of the clinical isolates, but only 41 (51.3%) of the bovine isolates, belonged to cluster 1, 2, or 3 (P < 0.001). Thirteen additional genotypes were identified in isolates from both cattle and humans (four genotypes), from only cattle (seven genotypes), or from only humans (two genotypes). Two other markers previously associated with isolates from cattle or with clinical isolates showed similar associations with genotype groups within bovine isolates; the tir allele sp-1 and the Q933W allele were under- and overrepresented, respectively, among cluster 1 to 3 genotypes. Stx-encoding bacteriophage insertion site typing demonstrated that there is broad genetic diversity of E. coli O157:H7 in the bovine reservoir and that numerous genotypes are significantly underrepresented among clinical isolates, consistent with the possibility that there is reduced virulence or transmissibility to humans of some bovine E. coli O157:H7 genotypes.     

Effect of Pre‐ and Post–Combined Multidoses of Epigallocatechin Gallate and Coenzyme Q10 on Cisplatin‐Induced Oxidative Stress in Rat Kidney

The nephroprotective effect of coenzyme Q10 and epigallocatechin gallate was investigated in rats with acute renal injury induced by a single nephrotoxic dose of cisplatin. Two days prior to cisplatin administration, epigallocatechin gallate and coenzyme Q10 alone and in four different combinations were given for 6 days. The treatment with antioxidants significantly protected the cisplatin‐induced increase in the levels of blood urea nitrogen and serum creatinine. Both the antioxidants alone or in different combinations significantly compensated the increased malondialdehyde and reduced glutathione levels. Moreover, the decrease in the activities of superoxide dismutase, catalase, and glutathione peroxidase and the concentration of selenium, zinc, and copper ions were significantly attenuated in renal tissue. In conclusion, epigallocatechin gallate and coenzyme Q10 are equally effective against cisplatin‐induced nephrotoxicity, whereas the intervention by combining these two antioxidants was found to be highly effective at low doses in attenuating oxidative stress in rat kidney.     

Evaluation of amino acid content and nutritional quality of transgenic soybean seeds with high-level tryptophan accumulation

Anthranilate synthase (AS) is a key regulatory enzyme in tryptophan (Trp) biosynthesis and is subject to feedback inhibition by Trp. The gene encoding a mutated feedback-resistant α subunit of rice AS (OASA1D) under the control of either a soybean glycinin gene promoter or the 35S promoter of cauliflower mosaic virus for seed-specific or constitutive expression, respectively, was introduced into soybean [Glycine max (L.) Merrill] by particle bombardment. A total of seven different transgenic lines that showed markedly increased accumulation of free Trp in their seeds were developed. The overproduction of free Trp was stably inherited in subsequent generations without any apparent detrimental effect on plant growth or reproduction. The total Trp content of transgenic seeds was also about twice that of nontransgenic seeds, whereas the amount of protein-bound Trp was not substantially affected by OASA1D expression. In spite of the marked increase in free Trp content, metabolic profiling by high-performance liquid chromatography coupled with mass spectrometry revealed little change in the amounts of other aromatic compounds in the transgenic seeds. We developed a rapid and feasible system based on farmed rainbow trout to evaluate the nutritional quality of a limited quantity of transgenic soybean seeds. Supplementation of fish food with OASA1D transgenic soybean seeds or with nontransgenic seeds plus crystalline Trp increased the growth rate of the farmed fish. These results indicate transformation with OASA1D is a reliable approach to improve the nutritional quality of soybean (or of other grain legumes) for human and animal food.     

Tightly clustered 11q23 and 22q11 breakpoints permit PCR-based detection of the recurrent constitutional t(11;22)

Palindromic AT-rich repeats (PATRRs) on chromosomes 11q23 and 22q11 at the constitutional t(11;22) breakpoint are predicted to induce genomic instability, which mediates the translocation. A PCR-based translocation-detection system for the t(11;22) has been developed with PCR primers flanking the PATRRs of both chromosomes, to examine the involvement of the PATRRs in the recurrent rearrangement. Forty unrelated carriers of the t(11;22) balanced translocation, plus two additional, independent cases with the supernumerary-der(22) syndrome, were analyzed to compare their translocation breakpoints. Similar translocation-specific junction fragments were obtained from both derivative chromosomes in all 40 carriers of the t(11;22) balanced translocation and from the der(22) in both of the offspring with unbalanced supernumerary-der(22) syndrome, suggesting that the breakpoints in all cases localize within these PATRRs and that the translocation is generated by a similar mechanism. This PCR strategy provides a convenient technique for rapid diagnosis of the translocation, indicating its utility for prenatal and preimplantation diagnosis in families including carriers of the balanced translocation.