Abstract  Subchronic administration of semicarbazide in the experiment with the rats was used to reduce the formaldehyde level in the organism in order to reveal the interaction between formaldehyde metabolism and biochemical parameters, which define the oxidant-antioxidant system condition and NO metabolism. It has been found that under semicarbazide impact the generation of free radicals, ROS, nitrite and nitrate were enhanced while aldehydes level was reduced that resulted from not only semicarbazide effect like the aldehydes acceptor, but the formaldehyde synthesis slowdown and acceleration of its transformation into format as well. We suppose that formaldehyde plays certain role in the development of connective tissue pathology.

Abstract  Formaldehyde is an unintentional byproduct of natural processes in homes and industry, particularly the manufacture of many consumer products. Accordingly, exposure is widespread, essentially indoors. At high doses, formaldehyde is a weak genotoxic agent and a human carcinogen that causes nasopharyngeal cancer (NPC). In this paper, we assess the risk of NPC associated with formaldehyde exposure in France. Exposure assessment is based on recent data published by the French Indoor Air Quality Observatory (Observatoire de la aualite de Pair interieur, OQAI). Characterization of risk using the US EPA unit risk estimates is incompatible with the incidence of NPC observed in France for the past 15 years. These results cast doubt on the appropriateness of using the linear non-threshold dose-response model recommended by the EPA and other institutions to assess the risk of formaldehyde-related NPC.

Abstract  BACKGROUND: Exposure to formaldehyde (FA) causes irritative effects and induces nasopharyngeal cancer; the International Agency for Research on Cancer (IARC, Lyon) classified FA as carcinogenic to humans, Group 1. Many studies have been published so far concerning the occupational exposure of industrial workers, embalmers, pathologists and anatomists to FA but very few data regarding medical examiners are available.

METHODS: To assess the extent to which subjects were exposed to FA, airborne concentrations of this chemical were measured by High Performance Liquid Chromatography (HPLC). In September-October 2006 we examined the personnel, which worked in an autopsy room (medical examiners) and in three laboratories of pathologic anatomy of the University Medical School of Bari, Policlinico Hospital, Southern Italy. Irritative effects were also investigated.

RESULTS: All the personal exposure data obtained exceeded the National Institute for Occupational Safety and Health Threshold Limit Value-Time Weighted Average (NIOSH TLV-TWA: 0.02 mg/m(3)) and, in a few cases, even the American Conference of Industrial Hygienists Threshold Limit Value-Ceiling level (ACGIH TLV-C: 0.37 mg/m(3)).

CONCLUSION: Irritative effects in more than 50% of the workers enrolled, increasing the risk of injuries.

Abstract  An experimental investigation has been made into the possibilities of retarding the progress of carious attack by infiltrating cariostatic material into enamel lesions. The problems associated with this kind of procedure are discussed against the background of experimental observations made using a formulation based on a resorcinol-formaldehyde resin.

Abstract  Some concern has been expressed in recent years about the use of formocresol for vital pulpotomy treatment of primary molars. This paper reviews the literature concerning the toxicity of formocresol and considers the evidence for the use of calcium hydroxide and glutaraldehyde. It is concluded that more work is required in this field before an alternative to formocresol can be recommended and that, in the meantime, a 1:5 dilution of the standard formocresol solution should be used but not included in the zinc oxide-eugenol sublining.

Abstract  This report, the first of a two-part study, was undertaken to quantitate the systemic distribution of formaldehyde from a pulpotomy site, and to compare this level to doses that elicit overt systemic pathology. Maxillary first molars of rats were pulpotomized and treated with 14C-labeled formaldehyde, for 5 minutes. Additionally, four groups of rats were infused with 10, 20, 30, or 50 percent of the first quantity applied to the site. The data show that approximately 30 percent of the 14C-formaldehyde placed in the pulp chamber was distributed systemically; 50 percent to 59 percent was expired as CO2; and 2 percent was excreted.

Abstract  Formocresol was checked with respect to its in vivo fixative effect after pulpotomy, through observation of tissue resistance to necrosis. The root pulps were freed from their hard-tissue wrapping and processed for 48 hours, followed or not by capping (15 days) with zinc oxide-eugenol or with zinc oxide-eugenol-formocresol. The effect of only capping with zinc oxide-eugenol, with or without formocresol, was also recorded.

Abstract  The purpose of this study was to compare pulpal and periapical tissue reactions to electrosurgery versus formocresol pulpotomy techniques in the primary teeth of dogs. The study was conducted on 33 primary teeth of three mongrel dogs between the ages of one to three months. Each dog had three teeth treated by Formocresol Pulpotomy with Mechanical Coronal Pulp Removal (FC), three teeth treated by Electrosurgery Pulpotomy with Mechanical Coronal Pulp Removal (ES/MCPR), three teeth treated by Electrosurgery Pulpotomy with Electrosurgical Coronal Pulp Removal (ES/ECPR), and two teeth serving as untreated Controls. Dogs one, two and three were sacrificed performing the pulpotomies at two, four and six weeks, respectively. The pulp, periapical tissue and after surrounding bone were submitted to histological examination and the histological reaction was recorded. The results were fourteen out of 18 unfavorable and zero out of three favorable histological reactions occurred in the FC treated teeth. Six out of 18 unfavorable and one out of three favorable histological reactions occurred in the ES/MCPR treated teeth. Nine out of 18 unfavorable and two out of three favorable histological reactions occurred in the ES/ECPR treated teeth. One out of 18 unfavorable and zero out of three favorable histological reactions occurred in the untreated Control teeth. The conclusion of this study is that of the three experimental groups, the teeth treated by Electrosurgery Pulpotomy with either Mechanical or Electrosurgical Coronal Pulp Removal exhibited less histopathological reaction than the teeth treated by Formocresol Pulpotomy.

Abstract  BACKGROUND: Mesenchymal stem cells (MSCs), a subpopulation of adult somatic stem cells, are an attractive stem cell source in regenerative medicine because of their multipotentiality. In this study, the effects of MSCs transplantation on oral ulcer healing were examined.

METHODS: Mesenchymal stem cells were isolated from bone marrow aspirates of dogs by dish adherence and expanded in culture. Oral ulcers were induced by topical application of formocresol in the oral cavity of dogs. Either autologous MSCs or vehicle (saline) was injected around the ulcer. The healing process of the ulcer was monitored clinically and histopathologically. Gene expression of vascular endothelial growth factor (VEGF) was detected in MSCs by reverse transcription-polymerase chain reaction. Expression of VEGF and collagen genes was detected in biopsies from all ulcers.

RESULTS: Mesenchymal stem cells expressed mRNA for VEGF MSCs transplantation significantly accelerated oral ulcer healing compared with controls. There was increased expression of both collagen and VEGF genes in MSCs-treated ulcers compared with controls.

CONCLUSION: Mesenchymal stem cells transplantation may help accelerate oral ulcer healing, possibly through the induction of angiogenesis by VEGF together with increased intracellular matrix formation as detected by increased collagen gene expression.

Abstract  The effects of humidity and sub-parts-per-million by volume contaminant levels on the photooxidation of formaldehyde and toluene are presented. UV radiation from a black-light lamp and a titania-coated glass-plate reactor were used to develop kinetic oxidation rates. The data indicated that competitive adsorption between water and the two contaminants has a significant effect on the oxidation rate. A simple differential design model is developed and validated using data from two ceramic foam photocatalytic reactors. The utility of rate data developed from the glass-plate reactor as the basis for reactor design models is demonstrated.

Abstract  OBJECTIVE: This study evaluated the response of periapical tissues to the endodontic sealer Endométhasone in root canal fillings short of or beyond the apical foramen.

MATERIAL AND METHODS: Twenty root canals of premolars and incisors of 2 mongrel dogs were used. After coronal access and pulp extirpation, the canals were instrumented up to a size 55 K-file and the apical cemental barrier was penetrated with a size 15 K-file to obtain a main apical foramen, which was widened to a size 25 K-file. The canals were irrigated with saline at each change of file. The root canals were obturated either short of or beyond the apical foramen by the lateral condensation of gutta-percha and Endométhasone, originating 2 experimental groups: G1: Endométhasone/short of the apical foramen; G2: Endométhasone/beyond the apical foramen. The animals were killed by anesthetic overdose 90 days after endodontic treatment. The individual roots were obtained and serial histological sections were prepared for histomorphological analysis (H&E and Brown & Brenn techniques) under light microscopy. The following parameters were examined: closure of the apical foramen of the main root canal and apical opening of accessory canals, apical cementum resorption, intensity of the inflammatory infiltrate, presence of giant cells and thickness and organization of the apical periodontal ligament. Each parameter was scored 1 to 4, 1 being the best result and 4 the worst. Data were analyzed statistically by the Wilcoxon nonparametric tests (p=0.05).

RESULTS: Comparing the 2 groups, the best result (p<0.05) was obtained with root canal filling with Endométhasone short of the apical foramen but a chronic inflammatory infiltrate was present in all specimens.

CONCLUSIONS: Limiting the filling material to the root canal space apically is important to determine the best treatment outcome when Endométhasone is used as sealer.

Abstract  We describe a cluster of four septicemias with pseudomonas, that occurred in a unit performing formaldehyde reuse of capillary dialyzers. Samples of blood, heparin solutions, dialysate and effluent of reused dialyzers, were evaluated bacteriologically and upon the adequacy of the reuse procedure. Pseudomonas aeruginosa, vesicularis and/or xanthomonas maltophilia were found on the blood cultures obtained during the septicemic reactions, and in the effluent of two reprocessed dialyzers not yet used (greater than 10(4) CFU/ml). These two dialyzers had also extremely low formaldehyde concentrations (0.0014 and 0.005% versus the expected 4%). Membrane and antibiogram characteristics of a Pseudomonas aeruginosa strain, recovered from the blood cultures in one patient, and of a strain found in the effluent of one of the two contaminated reprocessed dialyzers, were the same. The problem was attributed to the inadequate mixing of the disinfectant with the tap water used in the automated reprocessing device, in the absence of an alarm disclosing this failure.

Abstract  Formaldehyde released during hydrolysis of calcium-chelator esters incorporated into cells blocks glycolysis in the human erythrocyte (Tiffert, T., García-Sancho, J. and Lew, V.L. (1984) Biochim. Biophys. Acta 773, 143-156). This blockade is due to the inhibition of glyceraldehyde-3-phosphate dehydrogenase by NAD+ depletion caused by enzymatic oxidation of formaldehyde coupled to NADH production. The addition of pyruvate to the incubation medium prevents or reverts ATP depletion.

Abstract  Three cryoprotectant solvents, dimethylsulphoxide, 1,2-propanediol and glycerol, were investigated for a non-enzymatic reaction product, formaldehyde. All three cryoprotectants demonstrated a direct relationship between increasing solvent molarity and increasing formaldehyde concentration which was independent of temperature and protein (bovine serum albumin). Medium composition significantly influenced the formaldehyde concentration with HTF > T6 > M16 = M2. The formaldehyde could be effectively removed by reduced glutathione, cysteine and dithiothreitol with cysteine being the most effective scavenging agent. A reaction mechanism for this scavenging is proposed. The combination of cysteine and cryoprotectant reduced the zona pellucida 'hardening' effect in mouse oocytes.

Abstract  Formocresol, paramonochlorophenol, and calcium hydroxide are widely used in dentistry because of their antibacterial activities in root canal disinfection. However, the results of genotoxicity studies using these materials are inconsistent in literature. The goal of this study was to examine the genotoxic potential of formocresol, paramonochlorophenol, and calcium hydroxide using mouse lymphoma cells and human fibroblasts cells in vitro by the comet assay. Data were assessed by Kruskal-Wallis nonparametric test. The results showed that all compounds tested did not cause DNA damage for the tail moment or tail intensity parameters. These findings suggest that formocresol, paramonochlorophenol, and calcium hydroxide do not promote DNA damage in mammalian cells and that the comet assay is a suitable tool to investigate genotoxicity.

Abstract  A novel formaldehyde sensitive biosensor based on bacterial formaldehyde dehydrogenase (FDH) as a bio-recognition element has been developed. The bio-recognition membrane had bi-layer architecture and consisted of FDH, cross-linked with albumin, and of the cofactor NAD at a high concentration level (first layer). The second layer was a negatively charged Nafion membrane, which prevented a leakage of negatively charged NAD molecules from the bio-membrane. As transducers, gold electrodes SiO(2)/Si/SiO(2)/Ti/Au and electrolyte-insulator-semiconductor Si/SiO(2) (EIS) structures have been used. Changes in capacitance and impedance properties of the bio-recognition membrane have been used for monitoring formaldehyde concentration in a bulk solution. It has been shown that formaldehyde can be detected within a concentration range from 1 microM to 20mM depending on the type of transduction used, with a detection limit of 1 and 100 microM for gold-based and EIS-based transducers, respectively.

Abstract  A halotolerant Gram-negative eubacterium was isolated from soil collected at a storage site for formaldehyde near a chemical plant that uses formaldehyde in the production of glue. The strain, designated MA-C and identified as Halomonas sp. (DSM 7328), grew at salt concentrations from zero to above 20%. Halomonas sp. strain MA-C was found to be highly tolerant to formaldehyde and grew well in the presence of up to 75-100 mg/L formaldehyde. The isolate transformed formaldehyde at a high rate by means of a constitutive NAD- and glutathione-dependent formaldehyde dehydrogenase (EC 1.2.1.1). Previous exposure to formaldehyde resulted in an increase in formaldehyde dehydrogenase activity from 280-480 to 650-850 nmol . mg protein(-1) . min(-1). Formate did not accumulate in culture media enriched with formaldehyde, and formate added to cultures was rapidly metabolized. An inducible NAD-dependent formate dehydrogenase (EC 1.2.1.2) was detected (activity between 14 and 34 nmol NAD reduced mg protein(-1) . min(-1)). Radioactive labelling experiments showed that neither formaldehyde nor formate was incorporated into cell material to a significant extent.

Abstract  The reactivity of SiO2, MoO3/SiO2 and V2O5/SiO2 in the temperature range 400-800 degrees C and at atmospheric pressure has been thoroughly investigated by temperature-programmed reaction (TPR) measurements obtaining a continuous sequence of conversion, product distribution and reaction rate data, The effect of the contact time (0.083 less than or equal to tau less than or equal to 0.332 s) on the selectivity pattern and formaldehyde productivity (STYHCHO, g kg(cat)(-1) h(-1)) has been assessed. The onset temperature of formaldehyde formation (T-o,T-HCHO) accounts well for the reactivity of oxide catalysts in the methane partial oxidation (MPO), For all the systems studied the same sequence of onset temperature of product formation: T-o,T-HCHO < T-o,T-CO < T-o.CO2 < T-o,T-C2 proves that formaldehyde is the primary product of MPO on silica-based oxide catalysts. A suitable procedure for the calculation of conversion-selectivity data is pointed out. Full agreement between TPR data and continuous flow (CFR) and batch reactor (BR) isothermal measurements was found, The suitability of the TPR method as a fast and reliable tool for testing oxide catalysts in MPO is assessed.

Abstract  The effect of water vapor on the photooxidation of three gases was studied. The gases studied were formaldehyde (50000), toluene (108883), and 1,3-butadiene (106990). Variations in ultraviolet intensity and flow residence time were also considered. Titanium-dioxide (TiO2) was used as a photooxidative catalyst, and ultraviolet intensities in the milliwatt per square centimeter ranged were used. The data indicated that the reaction was first order for the three reactants at the sub part per million (ppm) level. The sub ppm level was chosen as the level found in actual buildings, transportation vehicles, and commercial aircraft. Competitive adsorption between water and trace contaminants had a significant effect on the oxidation rate. The dependencies of humidity and contaminant concentrations on the oxidation rates were considered to be the results of competitive adsorption on available hydroxyl adsorption sites and of changes in hydroxyl radical population levels. At the sub ppm level, the oxidation rate increased with decreasing humidity for humidity levels above 1,000ppm. The reaction rate was first order.