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PubMedDate not supplied

Use of polarization-sensitive optical coherence tomography to determine the directional polarization sensitivity of articular cartilage and meniscus.

The directional polarization sensitivity of articular cartilage and meniscus is investigated by use of polarization-sensitive optical coherence tomography (PS-OCT) by varying the angle of incident illumination. Experimental results show that when the incident light is perpendicular to the tissue surface, normal articular cartilage demonstrates little polarization sensitivity, while meniscus demonstrates strong polarization sensitivity. Differences in optical phase retardation produced by articular cartilage and meniscus are observed when the incident angle of the scanning light beam is adjusted between 0 and 90 deg relative to the tissue surface. Directional polarization sensitivity of articular cartilage and meniscus as obtained by PS-OCT imaging using variations in the angle of incident illumination can be used to assess the orientation and organization of the collagen matrix of these tissues. The polarization sensitivity as evidenced by the Stokes vector and optical phase retardation images can be explained by the orientation of the angle of illumination relative to the unique structural organization of the collagen fibrils and fibers of articular cartilage and meniscus.

Animals↗
PubMed1994

A comparison of the sensitivity of immunoperoxidase staining methods with high-sensitivity fluorescence flow cytometry-antibody quantitation on the cell surface.

Surface molecules present in low copy numbers can be detected with high-sensitivity fluorescence flow cytometry. Many cells previously thought not to express certain molecules on their surface can now be shown to have these molecules in very low copy numbers by high-sensitivity fluorescent cytometric methods. Detection of molecules by immunoperoxidase staining methods has not previously been compared with high-sensitivity flow cytometry techniques. Computerized video image analysis (VIA) is a method that allows measurement of area and density of the immunostain chromogen reaction product in a standardized fashion analogous to flow cytometry. In this study, we compared immunoperoxidase reaction products measured by VIA methods with high-sensitivity flow cytometric measurements for cells with 10,000 down to 50 antibody molecules bound to their surfaces. Detection of 100-200 surface molecules was possible with heavy metal-enhanced immunoperoxidase methods, whereas standard immunoperoxidase methods were not as sensitive. The sensitivity of the nickel-enhanced immunoperoxidase staining method was confirmed for detection of an epitope (Tac-IL2 receptor alpha-chain) present in low numbers on the surface of peripheral blood lymphocytes.

Antibodies, Monoclonal↗
PubMed2003

Elevated nitric oxide/peroxynitrite theory of multiple chemical sensitivity: central role of N-methyl-D-aspartate receptors in the sensitivity mechanism.

The elevated nitric oxide/peroxynitrite and the neural sensitization theories of multiple chemical sensitivity (MCS) are extended here to propose a central mechanism for the exquisite sensitivity to organic solvents apparently induced by previous chemical exposure in MCS. This mechanism is centered on the activation of N-methyl-D-aspartate (NMDA) receptors by organic solvents producing elevated nitric oxide and peroxynitrite, leading in turn to increased stimulating of and hypersensitivity of NMDA receptors. In this way, organic solvent exposure may produce progressive sensitivity to organic solvents. Pesticides such as organophosphates and carbamates may act via muscarinic stimulation to produce a similar biochemical and sensitivity response. Accessory mechanisms of sensitivity may involve both increased blood-brain barrier permeability, induced by peroxynitrite, and cytochrome P450 inhibition by nitric oxide. The NMDA hyperactivity/hypersensitivity and excessive nitric oxide/peroxynitrite view of MCS provides answers to many of the most puzzling aspects of MCS while building on previous studies and views of this condition.

Free Radical Scavengers↗
PubMed1999

Multiple chemical sensitivity: potential role for neural sensitization.

An emerging issue in environmental health is the phenomenon of multiple chemical sensitivity (MCS). Multiple chemical sensitivity is a controversial disorder characterized by multiorgan symptoms in response to low-level chemical exposures that are considered safe for the general population. The onset of MCS is often attributed to prior repeated chemical exposures in the home and/or workplace, and, once initiated, symptoms are triggered by extremely low levels of many chemicals/foods. No single case definition exists for MCS due to several issues that call into question its validity as a distinct illness induced by prior chemical exposure. Hypotheses regarding the etiological basis for MCS range from direct toxicological effects of chemicals to the notion that MCS is purely a psychological "belief system". One leading hypothesis suggests that MCS represents a neural sensitization phenomenon, wherein susceptible individuals demonstrate extreme sensitivity to chemicals and odor intolerance due to central nervous system (CNS) sensitization processes. The recent development of an animal model for MCS provides some support for the sensitization hypothesis and may offer evidence for behavioral changes observed in at least a subset of those reporting MCS.

Animals↗
PubMed2005

Herd sensitivity in relation to test sensitivity in swine vesicular disease serological tests.

After the swine vesicular disease (SVD) outbreaks in 1992 in the Netherlands a national monitoring programme was initiated, testing 12 samples from every pig farm three times per year. In this monitoring a slightly higher cut-off was used than the cut-off agreed on within the European community. The author has analysed the effect of this higher cut-off on the percentage of false positive and false negative results, using information on SVD antibody titres in sera obtained from the monitoring programme and the outbreaks in 1992 and 1994. The number of false positive results was reduced by 63% when using the higher cut-off. On average the test sensitivity was reduced from 100% to 88%, resulting in a change of the average herd sensitivity from 91.7% to 91.5%, when testing 12 samples per farm. When three samples per farm were tested, the average herd sensitivity changed from 64.9% to 62.9%. The results further indicate that, in contrast to what is generally presumed, there is a relationship between test sensitivity and the prevalence of infection. The results clearly show that sample size is far more important in obtaining a high herd sensitivity than achieving a high test sensitivity.

Animals↗
PubMed1985

[Unimicon-s (universal microbiological control--sensitivity) standardized medium for determining the antibiotic sensitivity of microorganisms].

A nutrient medium Unimicon-s for determination of antibiotic sensitivity of microorganisms is described. The medium is based on the raw material not used as a food, i. e. a clarified enzyme lysate of microbial biomass obtained at the All-Union Research Institute for Protein Synthesis. Unimicon-s provided satisfactory growth of various cultures and the sensitivity determination results analogous to those obtained with medium 1 (MPA) or Muller-Hinton medium recommended by the WHO as a standard medium for determination of microbial antibiotic sensitivity. The study on estimation of the fitness of the present criteria for dividing cultures by the sensitivity levels, i. e. into sensitive, moderate sensitive and resistant showed that with the use of an inoculation dose of 2.5 X 10(7) microbial cells per 1 ml the growth inhibition zones of the standard strains on the Unimicon-s medium were within the ranges of the permissible limits for medium 1. The Unimicon-s medium was tested with positive results in the laboratories of the A. N. Bakulev Institute of Cardiovascular Surgery and the 1st N. I. Pirogov City Clinical Hospital.

Amino Acids↗
PubMed1969

Advances in techniques of testing mycobacterial drug sensitivity, and the use of sensitivity tests in tuberculosis control programmes.

In a paper arising out of an informal international consultation of specialists in the bacteriology of tuberculosis held in 1961, an attempt was made to formulate criteria, and specify technical procedures, for reliable tests of sensitivity (the absolute-concentration method, the resistance-ratio method and the proportion method) to the 3 main antituberculosis drugs (isoniazid, streptomycin and p-aminosalicylic acid). Seven years later, a further consultation was held to review the latest developments in the field and to suggest how sensitivity tests might be put to practical use in tuberculosis control programmes. The participants reached agreement on how to define drug sensitivity and resistance, and stressed the importance of using a discrimination approach to the calibration of sensitivity tests. Their views are contained in the present paper, which also includes descriptions of the sensitivity tests used by the Medical Research Council of Great Britain for first- and second-line drugs (minimal inhibitory concentration and resistance-ratio methods), the two main variants of the proportion method developed by the Institut Pasteur, Paris, and a method for calibrating sensitivity tests.

Antitubercular Agents↗
PubMed1997

[Sensitivity loss of short wavelength sensitive cones in myopic eyes by blue-on-yellow perimetry].

A decrease of the short wavelength sensitive cone (S-cone) sensitivity has been reported in myopic eyes in addition to glaucoma and retinal diseases such as retinal detachment and diabetic retinopathy. In order to investigate early changes of visual function in myopic eyes, blue-on-yellow perimetry (B on Y) which could detect S-cone sensitivity and white-on-white perimetry (W on W) were measured with a computed perimeter program. Young subjects with good visual acuity, normal color vision, and normal intraocular pressure were selected. They had no other ophthalmoscopic abnormalities except for tigroid fundus. Mean deviations of W on W were reduced in mild and high myopic groups. In both tests, the sensitivities decreased as the refractive errors increased in all the tested areas (p < 0.0001). The sensitivity in B on Y decreased more remarkably than in W on W with an increase of refractive error (p < 0.05). We concluded that B on Y perimetry was significantly sensitive to identify early changes of visual function in myopic eyes.

Contrast Sensitivity↗