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At least 595 records · Page 33Linked to original sources

PubMed1998

[Effect of various salt solutions on ultraviolet B-induced erythema and pigmentation].

The combination of saltwater baths and subsequent ultraviolet irradiation is an effective treatment for psoriasis and atopic dermatitis. The aim of the present study was to determine the photosensitizing properties of two commercially available bath salts, original salt from the Dead Sea and sodium chloride. To address this issue, test areas on the volar aspects of the forearms were soaked with salt solutions for 15 minutes prior to ultraviolet-B (UVB) irradiation. The salt concentrations tested were 1%, 3% 5% and 15%. Tap water followed by UVB and UVB alone served as controls. Erythema was determined by visual and photometric measurement, and delayed tanning was assessed by colorimetry. Erythema obtained by wetting the skin prior to UVB irradiation was more pronounced than erythema induced by UVB alone. The most prominent erythema was yielded by tap water + UVB. The salts had a differing photosensitizing capacity and the strongest erythema was produced by the 5% solutions. There was only a moderate influence on delayed tanning by bathing the skin prior to irradiation. The results from the present study indicate that soaking the skin with salt solutions or tap water increases skin sensitivity to subsequent UVB irradiation. This may contribute to the effectiveness of salt water baths followed by UV irradiation and may account for an increased sunburn risk after bathing.

Adult↗

PubMed1999

[Patch testing with sodium lauryl sulfate: benefits and drawbacks in research and practice].

Patch testing with sodium lauryl sulfate (SLS) has been frequently used in the last decade. The evaluation of the SLS test can be performed visually, or with bioengineering methods. Among these, the transepidermal water loss is the most appropriate method, but measurements by laser Doppler flowmetry, colorimetry or corneometry may yield additional relevant data. Various factors such as age, area of testing or climatic conditions may also influence the SLS test, so such factors should be considered when different studies are compared. If correctly used, the SLS test can provide valuable information regarding the skin susceptibility to irritation. An overestimation of the test, just based on objective measurements with bioengineering methods, should be avoided, as the bioengineering data are capable of great precision and reproducibility, but can only define phenomena and not the causal event.

Dermatitis, Irritant↗

PubMed1996

Seasonal atrazine contamination of drinking water in pig-breeding farm surroundings in agricultural and industrial areas of Croatia.

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) a s-triazine herbicide, has been widely used in Croatian agriculture. Due to atrazine extensive use and its biodegradation in nature within at least one year (Klassen and Kodoum 1979), atrazine residues are found in ground, surface, drain and drinking water (Vidacek et al. 1994; Gojmerac et al. 1994). Groundwater downgradient from atrazine treated fields may show seasonal concentration peaks which could exceed the safe level (Wehtje et al. 1983). Therefore, the use of atrazine includes permanent control of its residues in water, particularly in relation to its use as a herbicidal chemical and groundwater contamination (Graham 1991). Furthermore, the presence of atrazine in the environment and its possible ingestion via the water, food and feed chain, may present a risk for the animal and human health. The analysis of atrazine residues in soil can be performed by either colorimetry or high performance liquid chromatography (HPLC) (Vickrey et al. 1980), and in water, soil and food by immunoassay in comparison with HPLC or gas chromatography/mass spectrometry (GS-MS) (Bushway et al. 1988; Bushway et al. 1989; Bushway et al. 1992; Thurman et al. 1990). We describe the use of enzyme-linked immunosorbent assay (ELISA) for one-year seasonal monitoring of atrazine residues in drinking water from two differently situated pig-breeding farms (agricultural and industrial areas) in Croatia. Results obtained by ELISA were compared to those produced by HPLC.

Agriculture↗

PubMed2003

Speciation of dissolved silicates in natural waters containing alkaline and alkaline-earth ions. A case study--waters from arid lands (North West China).

The concentration of silica in water samples from the desert area of Xinjiang, N. W. China, has been measured by colorimetry with ammonium molybdate. The observed pattern of dependence of the concentration of silica on the concentration of sodium ion (Na(+)) in the water samples is consistent with the pattern obtained by experiments on in-vitro dissolution of silica gel in sodium chloride (NaCl) solution. This indicates that the dissolution of silica in the hydrologic system in this area depends on the concentration of Na(+). Calcium ion (Ca(2+)), which is known to play an important role on the dissolution of silica on the basis of in-vitro experiments, was observed to take little part in the dissolution of silica in actual natural water samples. This implies that the Ca(2+) is bound to the hydrogen carbonate anion or that the Ca(2+) content of natural water containing salts is very low, owing to precipitation. In these samples silicate-Na(+) was identified as the dissolution species of silica; it was also ascertained that Ca(2+) did not form complexes with silicate species. These observations resulted from direct identification of dissolved chemical species by use of FAB-MS (fast atom bombardment mass spectrometry). The research indicates that in water samples in this critically arid region the concentration of "dissolved" silica is basically determined by the concentration of Na(+), indicative of pure inorganic conditions in the desert area of Xinjiang, N.W. China.

Journal Article↗

PubMed1997

Calcification of the lumbar vertebrae during human fetal development.

The calcification rate of the human fetal vertebrae has not been previously documented. In bridging this gap in knowledge, this report will specifically provide reference values for mineral content in predominantly trabecular bone during its formation in the prenatal period. Such information would facilitate early detection of ossification defects which become apparent in the fetal spine as early as 20 weeks of gestation [1]. Lumbar vertebrae were obtained at autopsy from 33 human fetuses aged 17-41 weeks of gestation. Vertebral demineralization was effected using an acid-alcohol solution. The extracted concentrations of calcium and phosphorus were determined spectrometrically from the solutions. Atomic absorption spectroscopy was used to determine calcium concentration and phosphate concentration was assessed by ultraviolet colorimetry. Mineralization could be described by a linear relationship over the age range studied. Calcium was taken up by the fetal vertebrae at twice the rate of phosphorus (0.2% per week). When the fetuses were classed according to similar gestational ages, the Ca/P weight ratios increased from 1.7 in the youngest group to 2.2 in the oldest group. The time of onset of calcification, calculated by extrapolation of the calcium data, appeared to be earlier than ultrastructural studies by other investigators suggest, but was subject to many uncertainties.

Calcification, Physiologic↗

PubMed2003

Fetal cricotracheal manipulation: effects on airway healing, cricoid growth and lung development.

The last decade has seen significant advance in the surgical management of pediatric subglottic stenosis, which remains one of the most fascinating problems of the laryngotracheal complex (LTC). Refined techniques for operating on these fragile structures should reduce cricotracheal scarring to a minimum, thus avoiding a lot of severe postoperative complications in a tricky moment of laryngeal's growing up. Experimental works indicates that the LTC growth is variously affected by longitudinal anterior, posterior or lateral incisions and actually the indications for laringotracheoplasty or cricotracheal resection in children with subglottic stenosis are still unclear. Reports on fetal manipulation of cricotracheal tissues are lacking as well as early effects on airway healing, LTC growth and lung development. The aim of this study was to evaluate if the airway mucosal healing is regenerative and scarless after cricotracheal manipulation in fetuses of New Zealand White Rabbits (NZWRFs). The consequences of fetal incisions on the cricoid growth and lung development are also examined, in a group of 12 NZWRFs, manipulated at 25+/-1 days of gestational age. The does underwent halothane anesthesia and all received a bilateral longitudinal cricoidotracheotomy. Twenty sham-operated fetuses were submitted to a limited cervicotomy (control's group). At the time of retrieval (31+/-0.5 days), en bloc laryngotracheobronchial tree and lungs were collected and processed for histological and morphometric analysis. Parameters recorded included: 1) histological full-thickness examinations focusing on inflammation, foreign body reaction, fibrosis, neochondrogenesis; 2) morphometric analysis, including the fetal Subglottic Diameter (FSD), the fetal Subglottic Area (FSA), the Radial Alveolar Count (rAC) and Computer Assisted Morphometric Colorimetry (CAmc); 3)analysis of lung hypoplasia (LH) by means of lung weight/body weight (LW/BW) ratio, protein and DNA indexes; 4) finally, different fractions of lung tissue phospholipids for lung maturity assessment were studied. Student's t test, when indicated, was performed for statistical analysis (p <0.05 = significant). There was no maternal mortality in this study. Ten fetuses were available for a final evaluation (16.6% mortality). In one case only, an incomplete closure of the fetal cricoidotomy was seen and could be probably due to a technical mistake. Mean fetal subglottic diameter and area were respectively 0.13+/-0.05 mm and 3.15+/-0.45 mm2 in both groups. As well as in fetal dermal repair, regeneration of the airway cartilage and mucosa were complete and scarless. LW/BW ratio, DNA content and analysis of different fractions of phospholipids were similar in experimental vs. the control group. These findings suggest that the healing processes were fibrosis-free and without evidence of scars. A complete closure of the incisions was achieved without stenosis of the fetal subglottic region. In addition, it seems that the fetal cricoidotracheotomy doesn't interfere with the laryngeal function which coordinate the amount of liquid leaving the lungs via the trachea. In addition, only a small leakage of amniotic fluid is shown and this could be responsible for normal and mature lungs.

Animals↗

PubMed2001

Molecular and cellular evidence for T-cell stimulation by allogeneic retinal pigment epithelium cells in vitro.

PURPOSE: The rejection of retinal pigment epithelium (RPE) allografts is a major barrier to long-term success after retinal transplantation. The aim of this study was to investigate the action of RPE cells on allogeneic T cells in coculture with or without macrophages. For the detection of T-cell activation the interleukins IL-1beta and IL-2, typical for this process, were investigated. METHODS: Human RPE cells (6 x 10(5) cells/flask) were used as stimulator cells. To investigate the influence of MHC class II molecules the RPE cells were pre-incubated with different concentrations of interferon-gamma (IFN-gamma; 0, 50, 100, or 250 U/ml) for 4 days. This was followed by coculture with either 6 x 10(6) T cells or, in a second trial, the T cells plus 6 x 10(5) macrophages. The mRNAs of the cytokines under study were detected using a reverse-transcriptase polymerase chain reaction and were quantified by colorimetry after 6 h. The cytokine protein content in the supernatants was measured after 20 h using specific enzyme-linked immunoabsorbent assays. RESULTS: Cytokine-specific mRNAs and proteins were found in all samples. After coculture the level of IL-1beta mRNA was higher and that of cytokine-specific protein was significantly increased. Furthermore, the addition of macrophages led to increased cytokine secretion but a general influence of the pre-activation with interferon could not be found. Similar results were detected for IL-2; at the highest dose, IFN-gamma preactivation and, in combination with macrophages, a significant increase in the protein level could be found. CONCLUSION: These results show that RPE cells are able to activate allogeneic T cells in vitro. Professional antigen-presenting cells may promote this process, as may pre-treatment with IFN-gamma. The circumstances modelled here are involved in the rejection process after RPE transplantation in humans and help to explain this immune response.

Adult↗

PubMed2004

Dietary cadmium intake in polluted and non-polluted areas in Japan in the past and in the present.

OBJECTIVE: The purpose of this data compilation is to overview past and current dietary exposure (primarily via rice) of general populations to cadmium (Cd) in environmentally polluted and non-polluted areas in Japan, and to compare the levels with counterpart levels in other areas in Asia. METHODS: A literature survey was conducted for publications on this subject, in either Japanese or international languages, since the early 1970s. Most of the studies identified employed the food-duplicate method in combination with atomic absorption spectrometry for Cd determination, although a few studies utilized other methods, such as the market basket method and dithizon-colorimetry. RESULTS: The highest estimate of dietary Cd intake (Cd-D), 600 microg Cd/day, was reported in the late 1960s for the local population in the Jinzu river basin, where Itai-itai disease had been endemic, and the Cd-D levels were 300 microg/day or higher in other polluted areas. Cd-D dropped to well below 100 microg/day when the polluted soil was replaced in the late 1970s and thereafter. In non-polluted areas, the Cd-D was reported to be approximately 100 microg/day in 1969, followed by a gradual decrease to approximately 40 microg/day in the late 1970s, to reach the current level of less than 30 microg/day. There is a trend of gradual reduction at the rate of 0.3 to 0.6 microg/day per year. Cd from rice accounted for 30 to 40% of the Cd-D in non-polluted areas, but a higher contribution was observed in some polluted areas. Nevertheless, the current Cd-D is still higher than the levels in other rice-dependent populations in east and south-east Asia. CONCLUSION: The Cd-D levels reported for polluted areas were in excess of 300 microg Cd/day. Substantial reduction in Cd-D to the level below 100 microg/day was observed after remediation, such as replacement of polluted paddy soil. In non-polluted areas, there has been a gradual decrease in Cd-D in the past 25 years. Nevertheless, the levels in the current intake of the general population in Japan (25 to 30 microg/day, or <1/10 of the levels in polluted areas in the past) is still higher than the levels in other rice-dependent areas in Asia.

Adult↗

PubMed2000

Monitoring of occupational exposure to tetrachloroethene by analysis for unmetabolized tetrachloroethene in blood and urine in comparison with urinalysis for trichloroacetic acid.

OBJECTIVE: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. METHODS: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. RESULTS: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. CONCLUSIONS: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA.

Adult↗

PubMed1999

Metal binding to the HIV nucleocapsid peptide.

Co(II) and Zn(II) binding constants have been measured for binding to the HIV-1 nucleocapsid N-terminal metal binding domain (residues 1-18), using competition titration methods and monitoring Co(II) binding by visible absorbance spectroscopy. Enthalpies for binding were directly measured by isothermal titration colorimetry. The results are compared with recent studies of related systems, including a study of Zn(II) binding by the full length protein.

Amino Acid Sequence↗

PubMed2003

Association of polymorphisms of paraoxonase 1 and 2 genes, alone or in combination, with bone mineral density in community-dwelling Japanese.

Oxidative stress may affect cellular functions in various pathological conditions, including osteoporosis. Paraoxonase 1 confers antioxidant properties on high-density lipoprotein, with which it is associated, by reducing the accumulation of lipid peroxidation products. We have now examined whether the 584A-->G (Gln192Arg) and 172T-->A (Leu55Met) polymorphisms of the paraoxonase 1 gene and the 959G-->C (Cys311Ser) polymorphism of the paraoxonase 2 gene are associated with bone mineral density (BMD) in community-dwelling Japanese (1,087-1,094 women and 1,112-1,125 men). The subjects were aged 40-79 years and were randomly recruited to a population-based prospective cohort study of aging and age-related diseases. BMD for the lumbar spine and right femoral neck was measured by dual-energy X-ray absorptiometry. Genotypes were determined with a fluorescence- or colorimetry-based allele-specific DNA primer-probe assay system. The 584A-->G and 172T-->A polymorphisms of the paraoxonase 1 gene and the 959G-->C polymorphism of the paraoxonase 2 gene were associated with BMD for the lumbar spine or femoral neck in postmenopausal women, with the 584 GG, 172 TT, and 959 CC genotypes representing risk factors for reduced bone mass. None of these three polymorphisms was associated with BMD in premenopausal women or in men. Our results suggest that the paraoxonase 1 and 2 genes are candidate loci for reduced bone mass in postmenopausal Japanese women.

Adult↗

PubMed2004

Evaluation of changes in the activity of proteolytic enzymes and their inhibitors in the processes that accompany the growth of gastric cancer.

BACKGROUND: Many investigators have observed a correlation between the aggressiveness of malignant tumor growth and the levels of cysteine peptidases and their autogenous inhibitors. Cathepsins B and L are activated by pepsin in an acidic pH. This fact encouraged us to measure the activity of these enzymes in tissue samples of gastric cancer. METHODS: We measured the activities of cathepsins B and L, and their precursors and inhibitors, in homogenates of tissue samples obtained from operations for gastric cancer. We compared the results for the homogenates of tissues from three different sites: the tumor center, the zone of cancer invasion (border of the tumor), and healthy tissue. RESULTS: The highest activities of free cysteine peptidases and those in complexes with their inhibitors, as well as their precursors, were observed in the border of the tumor, while the activities in healthy tissue were significantly lower. CONCLUSION: The local activities of cysteine peptidases and their inhibitors reflect the topographical differences between the center of the tumor, the zone of invasion, and healthy tissues in gastric cancer patients. In addition, the results for the pattern of changes in the activity of cysteine peptidases according to the degree of tissue infiltration were not dependent on the method of measurement (colorimetry vs spectrofluorometry).

Adult↗

PubMed2006

A new miniaturised optical system for chemical species spectroscopic detection based on a scanning integrated Mach-Zehnder microinterferometer on LiNbO3.

Absorption or emission spectroscopy is a powerful tool for detecting chemical compounds, diluted in fluid media: the sensitivity of this technique depends on the optical path of the source radiation, on the spectral window used for analysis and on the spectrometer performances. In this view, we designed and produced the first prototypes of an integrated scanning Fourier Transform Microinterferometer with Mach-Zehnder geometry, by using MEOS (Micro Electro Optical Systems) technologies. The microdevice, obtained by fabricating integrated optical waveguides on LiNbO(3) (LN) crystals, is electrically driven, without moving parts, by exploiting the electrooptical properties of the material. The microdevice operates the Fourier Transform of the input radiation spectral distribution, which can be reconstructed starting from the output signal by means of Fast Fourier Transform (FFT) techniques. The microinterferometer weights few grams, the power consumption is of a few mW and, in principle, can operate in the LN transmittance range (0.36-4.5 microm). The microinterferometer performances were preliminary tested in the (0.4-1.7 microm) spectral window. In the Visible region (0.4-0.7 mum) this microsystem demonstrated a spectral resolution suitable for detecting the characteristic lines of the solar spectrum together with the absorption bands of common gases present in Earth's atmosphere. In a further experiment we tested its performances for gas trace detection by using a calibrated NO(2) optical gas cell, showing the possibility to reveal up to 10 ppb, when suitable optical paths are used. Finally, colorimetry tests for the titration of an organic dye (E131) in alcohol solution are presented.

Crystallization↗

PubMed2005

Molecular cloning and expression of IL2 cDNA from the Tibet pig.

Interleukin-2 is a vital cytokine secreted by activated T lymphocytes, and plays important role in the regulation of cellular and humoral immunity of animals. In our experiment, IL2 cDNA of the Tibet Pig was first cloned by RT-PCR from ConA-stimulated lymphocytes in the blood and subcloned into pMD-18 T vector, which then was identified with endonuclease restriction. The sequencing result showed that Tibet pig IL-2 (TPIL-2) cDNA was 503 bp long (ORF was 465 bp) (Genbank accession number: AY 294018). The recombinant prokaryotic and eukaryotic expression plasmids of the cDNA were then constructed to analyse the ability to stimulate the proliferation of porcine lymphocytes in vitro. The recombinant porcine IL-2 expressed in the prokaryotic cells was found to be of 43 kDa molecular mass, which was consistent with a 17.4 kDa protein deduced from the IL-2 cDNA sequence (glutathione S-transferase molecular mass is 26 kDa); the recombinant protein in eukaryotic cells was confirmed by use of specific rabbit anti-porcine IL-2 serum in an ELISA. The bioactivity of TPIL-2 was detected through MTT colorimetry by stimulating the proliferation of pig ConA-stimulated blasts in vitro. The results indicate that the TPIL-2 significantly promoted the proliferation of ConA-stimulated blasts of pig. This confirms that IL-2 cDNA of the Tibet pig was successfully cloned and expressed in prokaryotic and eukaryotic cells, which lays the foundation for the the preparation of specific recombinant IL-2 protein and development of novel immune adjuvants to raise the immunity of pigs against various infectious pathogens and increase the immunoprotective efficacy of vaccines.

Animals↗

PubMed2001

New developments in the detection of vulnerable plaque.

Failure of coronary angiography (luminography) in prediction of future acute coronary syndromes has cast a shadow of doubt over the value of this old gold-standard technique. The fact that angiographically invisible or nonsignificant lesions cause the majority of acute coronary syndromes has driven scientists to develop new diagnostic methods. In this article, we review the ongoing worldwide research on both invasive techniques (such as intravascular angioscopy and colorimetry, ultrasound, thermography, optical coherence tomography, near infrared spectroscopy, Raman spectroscopy, fluorescence emission spectroscopy, elastography, magnetic resonance imaging and spectroscopy, nuclear immunoscintigraphy, electrical impedance imaging, vascular tissue doppler, and shear stress imaging) and noninvasive techniques (such as MRI, contrast-enhanced MRI with and without immunolabeled agents, electron beam computed tomography, multi-slice spiral / helical computed tomography, and nuclear imaging, including positron emission tomography). Each of these techniques and their potential combination holds promise for characterization of plaques responsible for acute coronary syndromes, namely vulnerable plaque.

Contrast Media↗

PubMed1983

Automated methods for detection of bacteriuria.

Urine specimens represent a large portion of cultures received by the clinical microbiology laboratory. Much time and effort are spent screening these specimens and approximately 80 percent show no growth. The methods employed for detection of bacteriuria include microscopic, chemical, culture, and automated. The most widely used procedure has been an agar plate culture method. However, this method requires overnight incubation and therefore results are delayed. Within the last decade many automated methods have been introduced for detecting bacteriuria, and results are available more rapidly than with the agar plate culture method. In addition to decreased detection time, these systems are accurate and cost-effective. The purpose of this report is to review these automated bacteriuria screening systems, which include bioluminescence, colorimetry, electrochemical screening, electrical impedance, microcalorimetry, photometry, and radiometry. Accuracy, detection time, and cost are also discussed in this review.

Adenosine Triphosphate↗

PubMed1983

Chromophoric peptide substrates for activity determination of animal aspartic proteinases in the presence of their zymogens: a novel assay.

Solid-phase synthesis was used for the preparation of pyroglutamyl-histidyl-p-nitrophenylalanyl-phenylalanyl-alanyl-leucine amide (I) and glycyl-glycyl-histidyl-p-nitrophenylalanyl-phenylalanyl-alanyl-leucine amide (II), two water-soluble and sensitive chromophoric substrates of chicken pepsin, hog pepsin A, and bovine spleen cathepsin D. The kinetic constants of hydrolysis of the p-nitrophenylalanyl-phenylalanyl bond of the substrates were measured by difference spectrophotometry at 308 nm (delta epsilon = 860 M-1 cm-1) and by ninhydrin colorimetry (substrate I, epsilon 570 = 2.31 X 10(4) M-1 cm-1). The pH optimum of cleavage is 5 for the pepsins and 3.7 for cathepsin D. Since all three proteinases still have a significant activity at pH 5.5-6 a new, simple assay was designed for submicrogram quantities of pepsins in the presence of pepsinogens without interference of the latter. The method is particularly suitable for the analyses of the zymogen activation mixtures.

Animals↗

PubMed1990

Differences in fluoride concentrations in the enamel surfaces of lower first premolars from young human males and females.

There are unconfirmed, reported differences in fluoride concentration in the tooth surfaces of male and female children whose average age was 13.5 yr (range 11.5-15.7 yr) and whose teeth might therefore have been exposed for 2-3 yr after eruption to the oral environment. Thirty-two unerupted and 24 erupted mandibular first premolars were now examined. These had been extracted for orthodontic reasons from children aged from 9 to 10 yr. Samples were removed by acid etching from small areas of the enamel surface, and the fluoride and phosphorus concentrations determined with an electrode and by colorimetry, respectively. Three sites on the buccal surface and one site in the centre of the lingual surface were investigated. Fluoride concentrations were higher in erupted than in unerupted enamel. The fluoride concentration of erupted enamel from the female teeth was significantly higher than that of the males (in contrast to the previous findings), although no analogous differences emerged in the fluoride concentrations of the unerupted enamel.

Bicuspid↗