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Spot Test (spot + test)
Selected AbstractsA spot test for detection of cobalt release , early experience and findingsCONTACT DERMATITIS, Issue 2 2010Jacob P. Thyssen Background: It is often difficult to establish clinical relevance of metal exposure in cobalt-allergic patients. Dermatologists and patients may incorrectly assume that many metallic items release cobalt at levels that may cause cobalt dermatitis. Cobalt-allergic patients may be unaware that they are exposed to cobalt from handling work items, causing hand dermatitis. Objectives: To present early findings with a newly developed cobalt spot test. Methods and Results: A cobalt spot test based on disodium-1-nitroso-2-naphthol-3,6-disulfonate was able to identify cobalt release at 8.3 ppm. The test may also be used as a gel test if combined with an agar preparation. We found no false-positive reactions when testing metals and alloys known not to contain cobalt. However, one cobalt-containing alloy, which elicited cobalt dermatitis in cobalt-allergic patients, was negative upon cobalt gel testing. Conclusions: The cobalt test detects amounts of cobalt release that approximate the elicitation concentration seen in cobalt-allergic patients. It may serve as a useful tool in dermatology offices and workplaces. [source] Cobalt release from inexpensive jewellery: has the use of cobalt replaced nickel following regulatory intervention?CONTACT DERMATITIS, Issue 2 2010Jacob Pontoppidan Thyssen Background: Before the introduction of the EU Nickel Directive, concern was raised that manufacturers of jewellery might turn from the use of nickel to cobalt following the regulatory intervention on nickel exposure. Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items. Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). Results: Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin,cobalt plating on these. Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future. Industries may not be fully aware of the potential cobalt allergy problem. [source] Assessing the impact of pollution on the Japaratuba river in Brazil using the Drosophila wing spot testENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2007Silmara de Moraes Pantalećo Abstract The Drosophila melanogaster somatic mutation and recombination test (SMART) was used to assess the genotoxicity of surface (S) and bottom (B) water and sediment samples collected from Sites 1 and 2 on the Japaratuba River (Sergipe, Brazil), an area impacted by a petrochemical industrial complex that indirectly discharges treated effluent (produced water) into the river. The genotoxicity tests were performed in standard (ST) cross and high bioactivation (HB) cross flies and were conducted on samples taken in March (dry season) and in July (rainy season) of 2003. Mutant spot frequencies found in treatments with unprocessed water and sediment samples from the test sites were compared with the frequencies observed for similar samples taken from a clean reference site (the Jacarecica River in Sergipe, Brazil) and those of negative (ultrapure water) controls. While samples from the Japaratuba River generally produced greater responses than those from the Jacarecica River, positive responses were detected for both the test and reference site samples. All the water samples collected in March 2003 were genotoxic. In July 2003, the positive responses were restricted to water samples collected from Sites 1 B and 2 S in the ST cross. The genotoxicity of the water samples was due to mitotic recombination, and the samples produced similar genotoxic responses in ST and HB flies. The spot frequencies found in the July water samples were considerably lower than those for the March water samples, suggesting a seasonal effect. The only sediment samples that were genotoxic were from Site 1 (March and July) and from the Jacarecica River (March). The genotoxins in these samples produced both somatic mutation (limited to the Site 1 sample in HB flies) and recombination. The results of this study indicate that samples from both the Japaratuba and Jacarecica Rivers were genotoxic, with the most consistently positive responses detected with Site 1 samples, the site closest to the putative pollution source. Environ. Mol. Mutagen. 48:, 2007. © 2007 Wiley-Liss, Inc. [source] Removal of amateur blue-black tattoos in Arabic women of skin type (III,IV) with Q-switched alexandrite laserJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2005Iqbal A Bukhari Summary Background and Objectives, Tattoos in Arabic society used to have a cosmetic importance on the face of females. These were usually amateur tattoos done by non-professional women in the tribe. Because Islam as a religion prohibited its practice and its application, people became concerned about removing the old tattoos by any means. Nowadays, laser is considered an effective method of tattoo removal. Here, we report our experience in the removal of tattoos in Arabic women of skin type III,IV using the Q-switched alexandrite laser. Study Design/Materials and Methods, Twenty female subjects aged 35,50 years from similar racial and ethnic background with amateur tattoos were treated using the Q-switched alexandrite laser. Fluence threshold was determined and a spot test was made. Q-switched alexandrite laser with a fluence range 4.0,7.5 J/cm2 (mean 6.05) was used at 6,12-week intervals. Total treatment numbers ranged from three to six sessions (mean 4.15) with single-pulse technique application. Results, More than 95% lightening was achieved in five patients after three to six sessions at fluence range of 6,7.5 J/cm2 and > 75% lightening in 10 subjects after three to six sessions of treatment at fluence range of 4,7.5 J/cm2. Pinpoint bleeding was observed in one case but no pigmentary alteration or scarring was seen. Conclusion, Tattoo pigment removal by Q-switched alexandrite laser is an effective method in skin type (III,IV) with minimal side effects, which gives high patient satisfaction. [source] PROTECTIVE CULTURES USED FOR THE BIOPRESERVATION OF HORSE MEAT FERMENTED SAUSAGE: MICROBIAL AND PHYSICOCHEMICAL CHARACTERIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2008JAZILA EL MALTI ABSTRACT In this paper, 150 isolates, originating from horse meat, were subjected to step-by-step screening and characterization to search for potential protective cultures to be used in the meat industry. Isolates were first tested on their homofermentative and salt tolerance. Second, the antibacterial capacities toward Listeria monocytogenes were determined in an agar spot test. In total, 50% of the tested isolates were inhibitory toward Listeria monocytogenes. However, only 12 isolates produced a bacteriocin. Finally, three isolates with the strong bacteriocin activity were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 15C under anaerobic conditions in a liquid broth. All three isolates combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. Lactobacillus sakei was used as starter culture for producing sausage horse meat. In this study, fermentations were followed analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 4.56. No Listeria monocytogenes, Salmonella spp. or sulfite reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the microbial safety of this product. The final water activity of the product was 0.85. Starter cultures showed that Lactobacillus sakei was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. PRACTICAL APPLICATIONS A starter culture can be defined as a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB) occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages. They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides and several enzymes is of importance. The main reason for suitability of LAB is their natural origin, and they can contribute to food safety and/or offer one or more organoleptic, technological, nutritional or health advantages. [source] Subtractive Screening for Probiotic Properties of Lactobacillus Species from the Human Gastrointestinal Tract in the Search for New ProbioticsJOURNAL OF FOOD SCIENCE, Issue 8 2007S. Delgado ABSTRACT:, In the search for new probiotics, 61 Lactobacillus spp. isolates, belonging to 12 species and isolated as dominant lactic acid bacteria from the feces of healthy humans, were subjected to a subtractive system of in vitro analyses, which included desirable and undesirable traits. Twenty-four isolates were able to grow in 2% bovine bile, of which 13 grew in acidified broth at pH 3.5 in acidified cysteine-containing MRS broth. Intrinsic resistance to certain antimicrobial agents (cefoxitin, metronidazole, vancomycin) was observed in most isolates, but atypical resistances to erythromycin, clindamycin, or tetracycline were also found in 5 strains. Undesirable traits such as ,-chymotrypsin or N-acetyl-,-glucosaminidase activities were not detected, but low ,-glucuronidase and moderate ,-glucosidase activities were recorded in 2 strains. Two Lactobacillus gasseri and 2 Lactobacillus paracasei selected strains inhibited several intestinal pathogens in an agar spot test, including strains of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. They also adhered to human Caco-2 and HT-29 epithelial cells in a manner comparable to Lactobacillus rhamnosus strain GG, and were unable to degrade pig gastric mucin in a plate assay. Together, these results suggest these 4 strains to be good probiotic candidates, concluding that the subtractive screening devised in this work could be a valuable tool in large-scale surveys for probiotics. [source] Genetic Toxicology of Dental Composite Resin Extracts in Somatic Cells In VivoBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 1 2010Guilherme Anziliero Arossi Homologous mitotic recombination, point and chromosomal mutation effects were determined in somatic proliferative cells of Drosophila melanogaster exposed to aqueous extracts of the clinically used composites. Reproducible increases in clone mutant spot frequencies induced by diluted extract of Fill Magic Flow were observed. These increments were exclusively associated to the induction of homologous recombination , a genetic phenomenon involved in the loss of heterozygosis. The other eight composite resins and the random extract had no statistically significant effect on total spot frequencies , suggesting that they are non-genotoxic in the somatic mutation and recombination test assay, which agrees with the applications they have in dentistry. These findings , supported by numerous studies showing a positive correlation between carcinogenicity in man and genotoxicity in the Drosophila wing spot test , point to the potential risks some composite resins pose to the health of patients and dentistry personnel. [source] Screening Tablets for DOB Using Surface-Enhanced Raman Spectroscopy,JOURNAL OF FORENSIC SCIENCES, Issue 5 2007Steven E. J. Bell Ph.D. Abstract:, 2,5,-Dimethoxy-4-bromoamphetamine (DOB) is of particular interest among the various "ecstasy" variants because there is an unusually long delay between consumption and effect, which dramatically increases the danger of accidental overdose in users. Screening for DOB in tablets is problematic because it is pharmacologically active at 0.2,3 mg, which is c. 50 times less than 3,4-methylenedioxy-N-methylamphetamine (MDMA) and makes it more difficult to detect in seized tablets using conventional spot tests. The normal Raman spectra of seized DOB tablets are dominated by the bands of the excipient with no evidence of the drug component. Here we report the first use of on-tablet surface-enhanced Raman spectroscopy (SERS) to enhance the signal from a low concentration drug. Raman studies (785-nm excitation) were carried on series of model DOB/lactose tablets (total mass c. 400 mg) containing between 1 mg and 15 ,g of DOB and on seized DOB tablets. To generate surface-enhanced spectra, 5 ,L of centrifuged silver colloid was dispensed onto the upper surface of the tablets, followed by 5 ,L of 1.0 mol/dm3 NaCl. The probe laser was directed onto the treated area and spectra accumulated for c. 20 sec (10 sec × 2). It was found that the enhancement of the DOB component in the model tablets containing 1 mg DOB/tablet and in the seized tablets tested was so large that their spectra were completely dominated by the vibrational bands of DOB with little or no contribution from the unenhanced lactose excipient. Indeed, the most intense DOB band was visible even in tablets containing just 15 ,g of the drug. On-tablet surface-enhanced Raman spectroscopy is a simple method to distinguish between low dose DOB tablets and those with no active constituent. The fact that unique spectra are obtained allows identification of the drug while the lack of sample preparation and short signal accumulation times mean that the entire test can be carried out in <1 min. [source] Increasing the uptake of hepatitis C virus testing among injecting drug users in specialist drug treatment and prison settings by using dried blood spots for diagnostic testing: a cluster randomized controlled trialJOURNAL OF VIRAL HEPATITIS, Issue 4 2008M. Hickman Summary., The objective of this study was to assess whether introducing dried blood spot testing can increase hepatitis C virus (HCV) diagnostic testing. A cluster randomized controlled trial was conducted. Sites were matched into pairs, with one site in each pair randomly allocated to receive the intervention (training and use of dried blood spot). Data were collected from all sites for 6 months before and 6 months after the start of the intervention. The participants were 22 specialist drug clinics and six prisons in England and Wales. The main outcome measure of this study was percentage point difference in individuals tested for HCV (the difference between the percentage of patients tested 6 months after and 6 months before the introduction of dried blood spot tests). Before the trial, 8% of patients at control and intervention sites had been tested for HCV, with 16 sites testing less than 5% of their caseload. The average percentage point difference between intervention and control sites was 14.5% (95% CI 1.3,28%, paired t -test, P = 0.03); with 13 of the 14 pairs contributing to the positive effect of the intervention (Wilcoxon matched-pairs signed-rank-test, P = 0.002). The size of the difference between intervention and control sites varied considerably. The study provides preliminary supporting evidence that dried blood spot testing may increase the uptake of HCV diagnostic testing, by increasing the opportunity for patients to be offered testing. Additional trials with a larger number of sites are justified, ideally in the context of drug and treatment policies that gave clearer priority (and targets) to infection control and testing. [source] Variations in the Thickness and Composition of the Skin of the GiraffeTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 9 2010Farzana Sathar Abstract This study examined the skin of two 1- to 2-year-old male giraffes and one adult male, determining skin thickness and histological structure with reference to it functioning as a component of the features required for the maintenance of blood pressure, dermal armor, or thermoregulation. It has been argued that a tight skin surrounding the extremities of the giraffe aids in the movement of fluid against gravity, hence preventing pooling of blood and tissue fluid (edema), but the skin has also been implicated in the thermoregulatory capacities and defensive anatomy of many mammalian species. In one of the younger giraffes, one-half of the skin was analyzed from which close to 170 sites were measured. In the other young and adult giraffes, spot tests to confirm the pattern observed in the fully analyzed individual were undertaken. It was discovered that the skin varied in thickness across the entire body and within regions of the body. Histological evaluation revealed that the skin was mostly collagenous, although interesting patterns of elastic fiber densities were also apparent. The skin in the neck and legs exhibited a morphology that may assist in cardiovascular regulation of blood flow to and from the head and legs, and the skin of the trunk and anterior neck has the possibility of functioning in a protective role. The analyses performed could not add any new data regarding the thermoregulatory role already described for giraffe skin. Anat Rec 293:1615,1627, 2010. © 2010 Wiley-Liss, Inc. [source] | ||||||||||||||||