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At least 217 records · Page 12Linked to original sources

PubMed1991

Platelet activating factor (PAF) effects on ciliary activity of human paranasal sinus mucosa in vitro.

The effect of PAF on ciliary activity was investigated in vitro. Normal human paranasal sinus mucosa was obtained from the ethmoid sinuses by surgical procedure and incubated in the form of tissue culture. Mucosal surface profile was viewed under an inverted microscope and ciliary activity was photoelectrically measured. Ciliary inhibition was significantly induced after a 60 min period of incubation with 10(-8) M PAF in vitro followed by irrigation. However, when the mucosa was irrigated after a 15 min incubation period the ciliary activity showed no remarkable change. The effect of 10(-8) M PAF on ciliary activity was completely blocked when pre-incubated and then incubated with 10(-6) M CV-3988 (a specific PAF receptor antagonist); however, it was moderately inhibited when only preincubated with CV-3988. These data indicate that PAF specifically affects ciliated cells in the first 60 min after the challenge.

Cells, Cultured↗

PubMed1992

Influence of sympathetic and parasympathetic substances in clinical concentrations on human nasal ciliary beat.

The effect of autonomic substances on ciliary beat in mucosal biopsies from the normal human nose was studied. The influence on ciliary beat frequency (CBF) as well as on ciliary beat harmony was measured photoelectrically. The sympathetic beta-agonist isoprenaline was found to have a stimulatory effect on CBF, whereas the alpha-agonist xylometazoline reduced CBF and ciliary beat harmony. The parasympathetic agonist carbachol had a positive effect on CBF. The sympathetic antagonists timolol (beta) and phentolamine (alpha) as well as the parasympathetic antagonist atropine had no effect. The effect of the agonists on ciliary beat was absent when they were administered in combination with their specific antagonists. These experiments indicate that, in clinical concentrations, the autonomic substances modify ciliary beat by a direct effect on the ciliated cells.

Adrenergic alpha-Agonists↗

PubMed1990

Angiotensin II stimulates airway ciliary motility in rabbit cultured tracheal epithelium.

We studied the effect of angiotensin II on ciliary activity in cultured rabbit tracheal epithelium in vitro. Administration of angiotensin II (10(-6) M) elicited an increase in ciliary beat frequency (CBF), as assessed by a photoelectric method, from the baseline value of 906 +/- 21 to 1260 +/- 33 beats min-1 (mean +/- SE, P less than 0.001). This ciliostimulatory effect was dose-dependent, with the maximal increase and EC50 value being 35.6 +/- 5.2% (P less than 0.001) and 5 x 10(-12) M respectively. Nifedipine, Ca2(+)-free medium, indomethacin and the phospholipase A2 inhibitor mepacrine, but not nordihydroguaiaretic acid, reduced the change in CBF. The ciliostimulation induced by angiotensin II was abolished by pretreatment of tissues with [Sar1-Ile8]angiotensin II, an angiotensin II receptor antagonist. Angiotensin II did not increase cyclic AMP levels in epithelial cells. These results suggest that angiotensin II interacts with its specific receptors and stimulates airway ciliary activity through a Ca2(+)-dependent prostaglandin release, without affecting intracellular cyclic AMP levels. Thus, angiotensin II may modulate mucociliary transport function in the respiratory tract.

Angiotensin II↗

PubMed2007

Microstructure design of nanoporous TiO2 photoelectrodes for dye-sensitized solar cell modules.

The optimization of dye-sensitized solar cells, especially the design of nanoporous TiO2 film microstructure, is an urgent problem for high efficiency and future commercial applications. However, up to now, little attention has been focused on the design of nanoporous TiO2 microstructure for a high efficiency of dye-sensitized solar cell modules. The optimization and design of TiO2 photoelectrode microstructure are discussed in this paper. TiO2 photoelectrodes with three different layers, including layers of small pore size films, larger pore size films, and light-scattering particles on the conducting glass with the desirable thickness, were designed and investigated. Moreover, the photovoltaic properties showed that the different porosities, pore size distribution, and BET surface area of each layer have a dramatic influence on short-circuit current, open-circuit voltage, and fill factor of the modules. The optimization and design of TiO2 photoelectrode microstructure contribute a high efficiency of DSC modules. The photoelectric conversion efficiency around 6% with 15 x 20 cm2 modules under illumination of simulated AM1.5 sunlight (100 mW/cm2) and 40 x 60 cm2 panels with the same performance tested outdoor have been achieved by our group.

Coloring Agents↗

PubMed1987

[Cilium movement of human oviduct].

In the present study, the frequency of cilium movement was measured by a photoelectric method at various sites in the human oviduct. The studies were performed to examine a possible difference between right and left oviducts, age-related differences, changes due to the menstrual cycle and pregnancy, and the effects of various drugs such as antibiotics, urokinase and corticosteroid (prednisolone). The results are summarized as follows: The frequency of cilium movement was 435.4 +/- 102.8 at the isthmus, 599.6 +/- 97.2 at the ampulla tubae, and 626.8 +/- 106.7 at the fimbriae, showing significant differences (p less than 0.05). However, no difference between the frequency in the right and left oviducts was detected. Number of cilia and/or ciliary cells changed periodically. The frequency of cilium movement appeared to increase in the late follicular phase as compared to both the early follicular phase and the luteinizing phase. This tendency was marked in the fimbriae. However, statistical analysis revealed no clear significance. No age-related differences were observed in the ciliary movements. Even after menopause, the ciliary movements could be observed. It was found that the ciliary movements decreased in pregnancy. Both PcG and CET inhibited the ciliary movements. Prednisolone at a concentration of 4.62 mg/ml inhibited the movement and even at 25 mg/ml did so at 90 min after the treatment. Urokinase did not inhibit the movements but rather stimulated the ciliary movements.

Adult↗

PubMed1983

The frog palate for studying mucus transport velocity and mucociliary frequency.

The palate of the frog possess a pseudostratified epithelium with mucus secreting cells and numerous ciliated cells covered with a continuous mucus blanket of 4 to 8 micron thickness. This palate can be used as a simple model for studying mucus transport and giving rapid information on the transportability of pathological bronchial secretion by the ciliary mechanism. The analysis of the relationship between the rheological properties of sputum an their transport rates on the frog palate showed that the highest transport rates were obtained with sputum samples characterized by a high spinability (Sp greater than 70 mm) and an intermediate range of viscosity (25-180 P) and elasticity (SR = 4-12 units). The mucociliary frequency (Fm) of the frog palate was measured by a photoelectric method and analyzed as a distribution function of the ciliary frequencies by the Fast Fourier Transform method. Fm decreased significantly after mucus depletion and was restored when adding a drop of frog mucus collected on a freshly excised frog palate. On the other hand, it remained about 20% lower than the original predepleted value, when adding purulent sputum collected in patients with chronic bronchitis and cystic fibrosis. The frog palate appears as a valuable model for analyzing the mucociliary transport rate and also for studying the effect of pathological secretions on the ciliary beating frequency.

Animals↗

PubMed1984

The potential role of photoelectron microscopy in the analysis of biological surfaces.

The photoelectric effect provides the basis for an imaging technique useful for the study of biological surfaces. The photoelectron microscope (PEM) employs a UV lamp to photoeject electrons from the specimen surface. The electrons are then accelerated and imaged using electron optics. Photoelectron micrographs often resemble scanning electron micrographs, but the origin of contrast is different and these two techniques are complementary. Scanning Electron Microscopy (SEM) is unsurpassed in applications where specimens have pronounced relief or where elemental analysis is required. The advantages of PEM are a new origin of contrast, high sensitivity to fine topographical detail, short depth of information, and low specimen conductivity requirements. Photoelectron images of model systems, cell surfaces and cytoskeletal elements have been obtained.

Animals↗

PubMed1998

Nitrogen dioxide compromises defence functions of the airway epithelium.

The effect of nitrogen dioxide (NO2) exposure on airway epithelial defence functions, such as ciliary activity, mucociliary transport velocity and junctional barrier function, remains to be elucidated. Our study investigates the effect of 24-h exposure to 3.0 ppm of NO2 on the airway epithelial defence functions in the healthy rabbit. Fifty-two healthy rabbits were exposed to 3.0 ppm of NO2 (NO2 group) or pure air (control group) for 24 successive hours in exposure chambers. After completion of the exposure sequence, the ciliary activity in the trachea was examined by a photoelectric method, the mucociliary transport velocity in the trachea by an endoscopic method and epithelial permeability of the trachea to fluorescein isothiocyanate-dextrans (FD-70s; molecular weight: 70,000 daltons) by an in vitro tracheal sac method. In the NO2 group, all epithelial defence functions, including ciliary activity, mucociliary transport velocity and epithelial permeability were significantly inferior to those in the control group. Although there was considerable overlap in the parameters examined between the two groups, approximately two-thirds of the animals were susceptible to 24-h exposure to 3 ppm of NO2. Dysfunction of both the junctional barrier and the mucociliary system could allow easier entry of allergen molecules to the airway parenchyma, where immunocomponent cells exist. NO2 might be involved to some extent in the clinical manifestation of airway allergic disorders through epithelial dysfunction.

Air Pollutants↗

PubMed1995

Reexamining the Mössbauer effect as a means to cleave DNA.

The ability of a DNA-bound Mössbauer isotope to absorb resonant gamma-radiation and subsequently, upon decay, induce DNA double-strand breaks by emission of low-energy Auger electrons was examined with a simple plasmid DNA cleavage assay. This mechanism was postulated by Mills et al. [Mills et al. (1988) Nature 336, 787] in the observed ablation of tumor cell growth with 57Fe(III)-bleomycin and Mössbauer radiation. The observed linearization of supercoiled pAA15 plasmid DNA upon treatment with five or more 57Fe(III)-bleomycin per plasmid precluded its use for testing Mössbauer effect induced cleavage. An alternative 57Fe-DNA-binding complex, [57Fe(phen)2(DPPZ)](PF6)2.H2O (57(1)), was synthesized and found to tightly bind DNA (K = 9.8 x 10(5) M-1) yet not induce DNA nicks or cuts at loadings of less than 500/pAA15 plasmid. Mössbauer irradiation of 57(1)/pAA15 samples under frozen and solution conditions does not result in observable linearization of the plasmid DNA over control samples. Some linearization is observed in all irradiated samples but is attributed only to the photoelectric effect.

Animals↗

PubMed1996

A new method for rapid determination of sperm concentration in turkey semen.

The routine determination of sperm concentration not only provides a measure of semen quality but also supplies a means of delivering precise sperm numbers in modern artificial insemination (AI) programs. Methods for estimating sperm numbers in laboratory settings (e.g., hemacytometer) are not practical for use in breeding facilities. A microprocessor-controlled semen analyzer (Densimeter, Model 534-B-Mod1, Animal Reproductive Systems) is commercially available for evaluating stallion semen. We calibrated and modified the semen analyzer to determine sperm concentration in turkey semen and to provide information on the required dilution for a constant AI dose. To calibrate the semen analyzer for turkeys, six samples of pooled semen (10 toms per sample) were collected by abdominal massage. A dilution curve of undiluted and 1:0.5, 1:1, 1:1.5, 1:2, 1:3, 1:5, and 1:10 diluted semen was established using Beltsville Poultry Semen Extender. Sperm concentration in diluted samples was determined by hemacytometer counts. The hemacytometer counts were used to develop an equation for estimating sperm concentration from the semen analyzer's absorbance readings and the equation programmed into the instrument. The newly developed program on the semen analyzer was subsequently validated by comparing instrument values for sperm concentrations with concurrent hemacytometer counts, which compared well to concentrations determined by a previously calibrated photoelectric colorimeter (Klett). Correlation coefficients between the semen analyzer and hemacytometer counts and the Klett and hemacytometer counts were r = 0.996 and r = 0.992, respectively (P < 0.001). The semen analyzer method was accurate and precise and could be beneficial to commercial turkey AI programs because it is easy to use, requires limited technological skills, and provides results for determining sperm concentration and AI dose in approximately 1 min.

Animals↗

PubMed1991

Clinical implications of I-125 dosimetry of bone and bone-soft tissue interfaces.

The dose to bone from I-125 photon interactions is expected to be approximately five times greater than the dose to soft tissue for the same photon fluence because of the dominance of the photoelectric effect. However, adverse clinical effects are not observed for I-125 implants near bone. Both the strong absorption of I-125 photons in bone and the narrowness (about 10 mu) of the high dose transition zone at a bone-soft tissue interface act to limit the volume of radiation sensitive tissue in the high dose region. Examples of calculated implant dose distributions in bone and in soft tissue cavities in bone are presented. Radiobiological measurements are consistent with the theoretical interface calculations. Calculation of the macroscopic dose distribution uses a recently measured radial dose function, while at the bone-soft tissue interface an analytic theory of the transition zone that is applicable to regular shaped cavities is used. Radiobiological experiments comparing cell survival for cells irradiated with 70 kvP X rays at Al-water and polystyrene-water interfaces are consistent with the transition zone calculations.

Bone and Bones↗

PubMed1996

Microdosimetric evaluation of relative biological effectiveness for 103Pd, 125I, 241Am, and 192Ir brachytherapy sources.

PURPOSE: To determine the microdosimetric-derived relative biological effectiveness (RBE) of 103Pd, 125I, 241Am, and 192Ir brachytherapy sources at low doses and/or low dose rates. METHODS AND MATERIALS: The Theory of Dual Radiation Action can be used to predict expected RBE values based on the spatial distribution of energy deposition at microscopic levels from these sources. Single-event lineal energy spectra for these isotopes have been obtained both experimentally and theoretically. A grid-defined wall-less proportional counter was used to measure the lineal energy distributions. Unlike conventional Rossi proportional counters, the counter used in these measurements has a conducting nylon fiber as the central collecting anode and has no metal parts. Thus, the Z-dependence of the photoelectric effect is eliminated as a source of measurement error. Single-event spectra for these brachytherapy sources have been also calculated by: (a) the Monte Carlo code MCNP to generate the electron slowing down spectrum, (b) transport of monoenergetic electron tracks, event by event, with our Monte Carlo code DELTA, (c) using the concept of associated volume to obtain the lineal energy distribution f(y) for each monoenergetic electron, and (d) obtaining the composite lineal energy spectrum for a given brachytherapy source based on the electron spectrum calculated at step (a). RESULTS: Relative to 60Co, the RBE values obtained from this study are: 2.3 for 103Pd, 2.1 for 125I, 2.1 for 241Am, and 1.3 for 192Ir. CONCLUSIONS: These values are consistent with available data from in vitro cell survival experiments. We suggest that, at least for these brachytherapy sources, microdosimetry may be used as a credible alternative to time-consuming (and often uncertain) radiobiological experiments to obtain information on radiation quality and make reliable predictions of RBE in low dose rate brachytherapy.

Americium↗

PubMed1979

Clinical application of a new endoscopic technique for detection of in situ bronchial carcinoma.

Hematoporphyrin is preferentially concentrated by cancer tissue and therefore is a potentially useful chemical marker. This report demonstrates the effectiveness of a photoelectric hematoporphyrin fluorescence detector used simultaneously with flexible fiberoptic bronchoscopy as a means of detecting and localizing bronchogenic carcinoma. The detector generates an audio signal when fluorescence is within the visual field of the bronchoscope. Of interest is that an audio signal was generated which indicated hematoporphyrin fluorescence in areas where no mucosal abnormality had been seen. These areas proved to be carcinoma in situ.

Aged↗

PubMedDate not supplied

Effects of calcitonin gene-related peptide on airway epithelial functions in dogs.

We studied the effects of calcitonin gene-related peptide (CGRP) on ciliary beat frequency (CBF) and electrical properties of canine tracheal epithelium by a photoelectric method and Ussing's short-circuit technique, respectively. CGRP dose dependently increased CBF, an effect that was accompanied by elevation of intracellular cyclic AMP but not affected by blockade of either Ca2+-influx or arachidonic acid metabolism. In contrast, CGRP elicited only a small and transient increase in short-circuit current without significant alterations in transepithelial potential difference or tissue conductance. These results suggest that CGRP may play a role in regulating airway mucociliary transport function.

Animals↗

PubMed1975

[A comparison of xero-tomography of the lung hilum with conventional tomography (author's transl)].

Because of its particular photoelectric properties, xero-tomography is particularly suited for the investigation of abnormalities in the hilar regions. It is superior to conventional tomography because of the improved edge contrast, which emphasises details of relatively non-opaque structures, and because of its high exposure latitude. This justifies its use despite the higher radiation dose that is necessary. The demonstration of relatively dense and of more transradient tissues on the same picture by xero-tomography, and the ability to read it by ordinary light, makes it less tiring to interpret than the translucencies of conventional radiographs.

Adult↗

PubMedDate not supplied

Submicrovolt full-field cone electroretinograms: artifacts and reproducibility.

The clinical utility of submicrovolt full-field 30-Hz (cone) electroretinograms was assessed by quantifying their contamination by electrical and photoelectric artifacts from xenon-flash stimulators and their test-retest variation in patients with retinitis pigmentosa. Artifacts obtained in saline with four commonly used electrodes varied with electrode type and consisted of an early, brief electrical component and a superimposed, extended photoelectric component. Techniques for minimizing these artifacts are described. Electroretinogram recordings from patients with advanced retinitis pigmentosa or congenital rod monochromatism indicate that these artifacts can be virtually eliminated with bipolar lenses. To assess test-retest variation, narrow-band-filtered responses were obtained twice during 6 weeks from patients with amplitudes less than 1 microV; threshold criteria for significant (p < 0.05) change in amplitude with this technique were approximately 0.25 log unit for each of two different systems.

Adolescent↗

PubMed1992

Digital blood flow in cooled and contralateral finger in patients with Raynaud's phenomenon. Comparative measurements between photoelectrical plethysmography and laser Doppler flowmetry.

The effects of cooling of a hand on lateral and contralateral digital skin blood flow were investigated in 18 patients with primary or secondary Raynaud's phenomenon. The aim of the study was to compare photoelectrical plethsmography (PhEP) and laser Doppler flowmetry (LDF). PhEP and LDF were used simultaneously for skin blood flow measurements of the third finger of both hands. One hand was cooled in water from 33 degrees to 3 degrees C in steps of 3 degrees C, each step lasting four minutes. It was followed by a recovery period of ten minutes in room air of 24 degrees C. During stepwise cooling from 33 degrees to 9 degrees C the relative PhEP and LDF values, measured on the cooled hand, decreased to 6.2% +/- 3.2% and 10% +/- 12% respectively. The correlation coefficients between LDF and PhEP varied between 0.79 and 0.99. In the contralateral hand the relative PhEP and LDF values decreased to 38% +/- 30.% and 64% +/- 7.9% respectively. The correlation coefficients between LDF and PhEP values were lower on the contralateral hand and ranged from 0.26 to 0.95. By calculating the LDF/PhEP ratios during cooling and recovery, more specific changes in red blood cell velocities during cooling were studied. Increasing LDF/PhEP ratios suggest increasing red blood cell velocities during cooling at 9 degrees C and a difference in the measuring methods. For testing the severity of Raynaud's phenomenon and the effect of treatment the results of both methods show consistent and quite comparable results when measured on the cooled hand. The effect of indirect cooling on the contralateral hand is, however, less consistent.

Adult↗

PubMed1986

Leukocyte migration inhibition in bacillus Calmette-Guérin vaccinated healthy adults and in tuberculosis assayed by a rapid photoelectric procedure.

A sensitive photoelectric method was used for reading migrations of human peripheral blood leukocytes from agarose microdroplets. Its rapidity enabled the use of a wide range (12 logs) of in vitro concentrations of antigen. Inhibition of migration of leukocytes (LMI) of healthy subjects having had BCG vaccination in childhood was found to occur in two zones of PPD concentrations, one high, from 10(-1) to 1000 micrograms/ml with a peak at 100 micrograms/ml, and one low, from 10(-8) to 10(-2) micrograms/ml. While three-fifths of subjects showed high zone LMI, in one-fifth it was bizonal and in another fifth observed only in the low zone. In patients with active pulmonary tuberculosis LMI, prior to all treatment, was reduced, absent, or replaced by enhanced migration, particularly in the low zone or in both zones. One and a half to four months after treatment LMI was found to be bizonal, enhanced migration having disappeared. These observations suggest the participation of two cell populations with widely different sensitivity to PPD in LMI in tuberculous and BCG vaccinated subjects and the presence of migration stimulatory lymphokine(s) during active tuberculosis.

Adult↗