Oral Pathobionts Promote MS-like Symptoms in Mice.

Dysbiotic oral microbiota has been associated with multiple sclerosis. However, the role and mechanism of oral microbiota in the development of multiple sclerosis are still elusive. Here, we demonstrated that ligature-induced periodontitis (LIP) aggravated experimental autoimmune encephalomyelitis (EAE) in mice, and this was likely dependent on the expansion of T helper 17 (Th17) cells. LIP increased the splenic richness of Enterobacter sp., which was able to induce the expansion of splenic Th17 cells and aggravate EAE in mice. LIP also led to enrichment of Erysipelotrichaceae sp. in the gut and increased Th17 cells in the large intestinal lamina propria of EAE mice. Fecal microbiota transplantation from EAE mice with LIP also promoted EAE symptoms. In conclusion, periodontitis exacerbates EAE, likely through ectopic colonization of oral pathobionts and expansion of Th17 cells.

[Research progress in association of neurological disorders and periodontal diseases].

Periodontal diseases are inflammatory diseases caused by oral pathogens around the periodontal supporting tissues, leading to systemic and chronic inflammatory conditions. The continuous chronic systemic inflammation may be a trigger of neuroinflammation, which is the prominent feature of a variety of neurological disorders. It implies that there may be a causal link between periodontal diseases and neurological disorders. This article presents epidemiological and biological evidences that periodontal diseases can induce or exacerbate neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis and major depressive disorder, and analyzes the possible mechanisms. The importance of maintaining oral health as well as preventing and treating periodontal diseases are emphasized. At the same time, this may provide novel approaches to study the relationship between periodontal diseases and neurological disorders in the prevention and treatment strategies of neurological disorders.

A novel HLA-C allele, Cw*0119, isolated from the Han Chinese.

A novel HLA-C allele, Cw*0119, which was identified from an individual of the Han Chinese, differs from Cw*010201 at codon 76 (AGC-->TGC) and codon 178 (CTG-->CCG).

Scavenging effects of natural phenols on oxidizing intermediates of peroxynitrite.

Most of peroxynitrite (ONOO-/ONOOH) is formed via the diffusion-limited reaction between nitric oxide and superoxide. In biological systems, the decomposition of ONOO- yields 30-35% of carbonate radical (CO3*-) and nitrogen dioxide (NO2*), which are strongly oxidizing intermediates and are suggested to take a part of the responsibility for the toxicity of nitric oxide (NO*) or ONOO-. Therefore, the current study focuses on the scavenging activities of phenols toward CO3*- and NO2* to protect biomolecules from damage caused by NO* or ONOO- using the technique of pulse radiolysis. From the build-up kinetic of the phenoxyl radicals and the decay kinetic of CO3*- radical, the rate constants of scavenging reactions were determined to be 1.9-3.4 x 10(8) M(-1) x s(-1) and 0.11-1.9 x 10(8) M(-1) x s(-1) for CO3*- and NO2* respectively. The results indicated that the tested phenols are the efficient scavengers of CO3*- and NO2*.

Triplet state mechanism for electron transfer oxidation of DNA.

The interaction of anthraquinone-2-sulfonate with nucleotides and DNA in acetonitrile and acetonitrile water solvent mixture have been studied using KrF laser photolysis aimed at elucidation of the reaction mechanism. Laser spectroscopy directly demonstrates that the initial species from interaction of anthraquinone-2-sulfonate with nucleotides are radical cations of nucleotides and radical anion of anthraquinone-2-sulfonate. In addition, formation of ion pair from interaction of any of nucleotides with anthraquinone-2-sulfonate is synchronous with decay of triplet anthraquinone-2-sulfonate, which has provided dynamic evidence for initiation of electron transfer from DNA bases to triplet anthraquinone-2-sulfonate. Moreover, direct observation of stabilized DNA guanyl radical cation from interaction of anthraquinone-2-sulfonate with DNA has provided initial evidence for selective cleavage of DNA at guanine moiety. The solvent-separated ion pairs in acetonitrile have evidently dissociated into free ions, thereby enabling independent study of the behavior of guanyl radical cations and radical anion of anthraquinone-2-sulfonate.

Towards a control model for the highly cybernetic farming ecosystems.

A dynamic model based on the linear systems theory is developed in designing a highly cybernetic farming strategy to efficiently manage residuals generated in farm ecosystems. A linear cybemetic model would be used to describe the dynamic behavior of resource flow in the farm ecosystem in which the state variables are resource quantities, and the control variables are residual quantities. The controlled process is defined as the controlled management strategy change. Cybemetic mechanism shows the application of residuals as control measures have determinate effects on the controlled process as along as the farming system is observable and controllable in the control sense. To illustrate the model algorithm the idea is applied to simulate the dynamic response of residual phosphorus concentrations in an integrated pig/corn farming system located in the south Taiwan region. General results show that the residual phosphorous concentration is influenced by farming activities which are controlled by a system of gross input and net output parameters. This paper demonstrates using input-output analysis technique that residuals generated in the farming system is the most important cybemetic variable,

Dynamic mathematical model for biotransformation and mass transfer of livestock generated VOC-odor in a bioactive dust practice system.

A multi-step mass transfer-biodegradation model is developed to describe the bioactive adsorber dynamics for the biotreatment of livestock generated odor causing VOCs (VOC-odor) based on a biologically active dust particle (BADP) process. The BADP process employs dust particles with adsorbat-acclimated microbial culture to form the bioactivated dust particles (BDP) for the simultaneously adsorption, mass transfer, and biodegradation of VOC-odor. The model incorporating age and size distributions of BDP considers the equilibrium partitioning of VOC-odor at BDP and bulk gas interface that followed by two kinetic processes occurring in the bulk and solid phases: bulk gas mass transfer-biodegradation and BDP biofilm diffusion-biodegradation. Analytical equations indicate that the overall biotransformation rate of VOC-odor in a BADP process is controlled by BDP-bulk gas equilibrium processes represented by the slowest of two kinetic processes determined by a dimensionless group: the Thiele modulus (phi 2), the Damkohler number (Da) and the Biot number (Bi). Computer simulations demonstrate that the most favorable performance of a BADP system in reducing VOC-odor concentrations is operated under Bi < 1, Da < 1, or Bi > 1 phi 2 < 1; indicating diffusion-biodegradation controlled. The dimensionless group can be used to identify the dominant rate-limiting processes and to evaluate the overall biomineralization rate in a BADP process. Simulation results allow the determination of preliminary design for prototype development.

Interaction of hydroxycinnamic acid derivatives with the Cl3COO radical: a pulse radiolysis study.

The electron transfer reactions between the trichloromethylperoxyl radical (Cl3COO*) and hydroxycinnamic acid derivatives, including chlorogenic acid, sinapic acid, caffeic acid, ferulic acid and 3,4-(methylenedioxy)cinnamic acid, have been studied by pulse radiolysis. The hydroxycinnamic acid derivatives, especially sinapic acid, are identified as good antioxidants for reduction of Cl3COO* via electron transfer reactions. From buildup kinetic analysis of phenoxyl radical, the rate constant for reaction of Cl3COO* with sinapic acid has been determined to be 8.2x10(7) dm3 mol(-1) s(-1), while the rate constants of electron transfer from other hydroxycinnamic acid derivatives to Cl3COO* were obtained to be about 2x10(7) dm3 mol(-1) s(-1). The reaction of 3,4-(methylenedioxy) cinnamic acid with Cl3COO* was investigated as an evidence for the electron transfer mechanism.

Resonators for self-mode-locking Ti:sapphire lasers without apertures.

It is advantageous to achieve stable self-mode locking without hard apertures by designing resonators to minimize cavity-dispersion noncoaxiality in Brewster-cut gain media. The cavity-loss modulation introduced by Kerr effects is then optimized.

Femtosecond optical ranging of corneal incision depth.

Excimer laser ablation has been proposed as a technique for keratorefractive surgery. Clinical acceptance of linear-incision laser keratectomy may depend on the availability of a method for accurately and noninvasively monitoring incision depth during the ablation process. We have developed a femto-second optical ranging technique for measurement of corneal incision depth. This technique uses nonlinear optical cross-correlation to determine the time-of-flight of an ultrashort laser pulse between the anterior corneal surface and the bottom of the keratectomy incision. Longitudinal and transverse resolution are estimated to be 5 micron and 10 micron, respectively.

Interferometric technique for investigation of laser thermal retinal damage.

We describe a new technique for investigating laser-tissue interactions based on the use of an interferometric laser exposure pattern. A Michelson interferometer is used to generate a sinusoidal fringe exposure pattern. The periodicity of the fringe pattern may be adjusted from macroscopic dimensions to a scale of microns without the need for an imaging plane. Since fringe pattern periodicity is more adjustable and directly measureable than laser spot size, this technique offers significant advantages for studying the effects of thermal damage and diffusion in the irradiated tissue. In addition, the comparison of tissue response with theoretical models is simplified since the sinusoidal fringe pattern is itself an eigenfunction of the thermal diffusion equation. This technique is demonstrated for argon laser photocoagulation in the rabbit retina. Exposures at durations comparable to the thermal relaxation time produced spatially confined lesions, while those at much longer durations resulted in significant diffusion of the thermal damage beyond the primary targeted regions. The role of thermal diffusion can thus be assessed directly from the ophthalmoscopic and histologic appearances of the lesions. This technique can be employed to study thermal diffusion and other transport phenomena occurring in laser-tissue interactions for a variety of laser sources and tissue targets.

Time-resolved studies of Nd:YAG laser-induced breakdown. Plasma formation, acoustic wave generation, and cavitation.

The use of high intensity ultrashort pulsed laser radiation to produce optical breakdown is an important approach for the surgical treatment of intraocular structures. We have investigated the transient properties of Nd:YAG laser induced breakdown in a saline model using time-resolved spectroscopic techniques. Spatially resolved pump and probe techniques are applied to study the dynamic behavior of the plasma formation, acoustic wave generation, and cavitation processes which accompany the optical breakdown. Measurements of plasma shielding and luminescence indicate that the laser induced plasma forms on a subnanosecond time scale and has a lifetime of several nanoseconds. An acoustic transient is generated at the breakdown site and propagates spherically outward with an initial hypersonic velocity, then loses energy and propagates at sound velocity. Transient heating following the plasma formation produces a liquid-gas phase change and gives rise to cavitation or gas bubble formation. This gas bubble expands rapidly for several microseconds, then slows to reach its maximum size and finally collapses.

Optical activity and conformation of beta-bungarotoxin in solution.

beta-Bungarotoxin, which consists of two polypeptide chains (A- and B-chain), in the venom of Formosan banded krait is stable in 7.5 M urea but can be denatured in 6.0 M guanidine hydrochloride. Its conformation remains virtually the same in solvents of lower polarity than water such as a mixture of 1,2-ethanediol-water (4:1 by volume). The circular dichroism spectrum in water shows a double minima at 222 and 209 nm, which is characteristic of the helical structure. The ellipticities at these two wavelengths indicate that the helical content of this toxin is not high. Comparing how guanidine hydrochloride effects the helix-coil transition of the toxin with that of phospholipase A2's which are structurally homologous to A-chain implicates that the two polypeptide chains should be coexisted and interacted with each other in order to maintain the active conformation of beta-bungarotoxin. Removal of eight amino acid residues from the N-terminus of the A-chain by action of CNBr on beta-bungarotoxin does not disrupt the polypeptide folding but abolishes the neurotoxicity.