Fungal Infection of the Radicular Dentin Siqueira, José F.; Rôças, Isabela N.; Lopes, Hélio P. ...
Journal of endodontics,
11/2002, Letnik:
28, Številka:
11
Journal Article
Recenzirano
Although fungi have been detected in infected root canals, their precise role as endodontic pathogens has not yet been elucidated. The purpose of this study was to investigate the pattern of ...radicular dentin colonization by five fungal species. Bovine root sections were infected with each of the following fungal species:
Candida albicans, Candida glabrata, Candida guilliermondii, Candida parapsilosis, and
Saccharomyces cerevisiae. After 14 days, the sections were fixed in glutaraldehyde, split into two halves, critical point-dried in CO
2, sputter-coated with gold, and examined under scanning electron microscopy. Regardless of the species, single or budding yeast cells were the only fungal forms observed.
C. albicans colonized most of the specimens. On the other hand, the other four fungal species presented discrete or no colonization of the radicular dentin.
C. albicans showed different patterns of dentin infection. In some specimens, colonization of the dentinal surface was slight and no penetration within dentinal tubules was observed. In the other specimens, some areas of the root canal walls were covered with large colonies of yeast cells and some dentinal tubules were heavily infected. The results suggested that whereas
C. albicans showed the ability to colonize dentin, the other four fungal species did not. This can help to explain why
C. albicans is the fungal species most often found in endodontic infections.
Tecoma stans (yellow elder) has shown medicinal properties and antimicrobial activity. Previous reports on antifungal activity of T. stans preparations and presence of trypsin inhibitor activity from ...T. stans leaves stimulated the investigation reported here. In this work, we proceeded to the purification and characterization of a trypsin inhibitor (TesTI), which was investigated for anti-Candida activity. Finally, in order to determine the potential of TesTI as a new natural chemotherapeutic product, its cytotoxicity to human peripheral blood mononuclear cells (PBMCs) was evaluated. TesTI was isolated from saline extract by ammonium sulfate fractionation followed by ion exchange and gel filtration chromatographies. Antifungal activity was evaluated by determining the minimal inhibitory (MIC) and fungicide (MFC) concentrations using fungal cultures containing only yeast form or both yeast and hyphal forms. Candida cells treated with TesTI were evaluated for intracellular ATP levels and lipid peroxidation. Cytotoxicity of TesTI to PBMCs was evaluated by MTT assay. TesTI (39.8 kDa, pI 3.41, K i 43 nM) inhibited similarly the growth of both C. albicans and C. krusei culture types at MIC of 100 μg/mL. The MFCs were 200 μg/mL for C. albicans and C. krusei. Time-response curves revealed that TesTI (at MIC) was more effective at inhibiting the replication of C. albicans cells. At MIC, TesTI promoted reduction of ATP levels and lipid peroxidation in the Candida cells, being not cytotoxic to PBMCs. In conclusion, TesTI is an antifungal agent against C. albicans and C. krusei, without toxicity to human cells.
Objective: The purpose of the present investigation was to examine the microbiota of acute periradicular abscesses of endodontic origin by using a molecular genetic method. Study Design: Pus was ...collected by aspiration from 27 cases diagnosed as acute abscesses of endodontic origin, and DNA was extracted to evaluate the occurrence of 49 bacterial species by using whole genomic DNA probes and checkerboard DNA-DNA hybridization. The presence of bacterial DNA in clinical samples was confirmed by polymerase chain reaction with ubiquitous bacterial 16S rRNA gene primers. Results: The results of the checkerboard DNA-DNA hybridization analysis revealed that 37 of the 49 DNA probes tested were reactive with one or more samples. The number of bacterial species in the pus samples ranged from 1 to 33 (mean, 5.9). Eighteen of the 27 pus samples were positive for at least one DNA probe. The most prevalent species found were: Bacteroides forsythus (29.6% of the cases); Porphyromonas gingivalis (29.6%); Streptococcus constellatus (25.9%), Prevotella intermedia (22.2%), Prevotella nigrescens (22.2%), Fusobacterium periodonticum (18.5%), Fusobacterium nucleatum subspecies nucleatum (18.5%), and Eikenella corrodens (18.5%). Conclusions: The microbiologic data of the present investigation indicated that molecular genetic methods could provide additional knowledge regarding the microbiota of acute periradicular abscesses by detecting bacterial species that are difficult—or even impossible—to grow. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:451-7)
Hydrogen sulphide (H2S) represents one of the main odorant gases emitted from wastewater treatment plants (WWTP) and a mathematical model can be a fast and low cost tool to estimate its emission. In ...this work H2S emission rates in a WWTP, composed of an up-flow anaerobic sludge blanket (UASB) reactor and an aerobic biofilter (BF), are estimated using four mathematical models available in the literature (AP-42, GPC, TOXCHEM + and WATER8). The results show that the GPC model leads to the best agreement with the experimental data, except for the biofilter due to its lack of capability to include biodegradation as a H2S removal process. On the other hand, the AP-42 and WATER8 models showed a slightly better ability to predict H2S removal in the biofilter than the TOXCHEM + model, as all models underestimate the H2S concentration decay.
Aim
A 16S rDNA‐based polymerase chain reaction (PCR) method was used to detect the occurrence of Treponema denticola in root canals.
Methodology
Samples were collected from 54 single‐rooted teeth ...having carious lesions and necrotic pulps. DNA extracted from the samples was amplified using the PCR assay, which yielded a specific fragment of T. denticola 16S rDNA.
Results
T. denticola was detected in 10 of 29 asymptomatic cases (34.5%), eight of 15 root canals that were tender to percussion (53.3%), and five of 10 teeth with acute periradicular abscess (50%). In general, T. denticola was found in 23 of 54 cases (42.6%).
Conclusions
Findings suggest that T. denticola can be involved in the pathogenesis of periradicular lesions of endodontic origin.
This study aimed to estimate the methionine & cystine (M&C), and threonine (THR) requirements for maintenance of adult roosters differing in liveweight and body composition, and to estimate the ...concentrations of M&C and threonine in 'ideal' protein for maintenance. Five metabolism trials were conducted using 42 mature Bovans White (in trials 1 and 3) and 42 Cobb (in trials 2 and 4) roosters. In the first two trials, designed to measure the M&C requirements for maintenance, the M&C content in the diets ranged from 0 to 138 mg/kg d (687 mg/BPm 0.73/d) for the Bovans White, and from 0 to 64 mg/kg d (346 mg/BPm 0.73/d) for the Cobb strain, respectively (where BPm is mature body protein weight). In trials 3 and 4 in which the THR requirement for maintenance was measured, the THR levels ranged from 0 to 127 mg/kg d (624 mg/BPm 0.73.u/d) and from 0 to 106 mg/kg d (584 mg/BPmm 0.73.u/d) for the two strains, respectively. Excreta were collected in trays, weighed, homogenized, dried and ground and the nitrogen contents of excreta and diets were then determined. The M&C requirement for maintenance was estimated as 19 mg/kg empty body weight (EBW)/d, 26 mg/kg EBW0.75/d or 87 mg/BPm 0.73/d. The maintenance requirement for THR was estimated as17 mg/kg EBW/d, 22 mg/kg EBW0.75/d or 76 mg/BPm 0.73/d. The concentration of M&C in 'ideal' protein for maintenance was estimated as 11, and THR, 9.4 g/kg body protein.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the present work, a fast acid digestion method was applied to the determination of cadmium in urine samples by electrothermal atomic absorption spectrometry (ET AAS). The pyrolysis and atomization ...temperatures were 400 and 1200
°C with a characteristic mass of 1.3
pg. Quantification was made with matrix matching calibration curves. The method was validated by the analysis of certified urine samples. Differences were not observed among the levels of the metal in populations from metropolitan and rural areas. The limit of detection (LOD,
k=3,
n=10) was 0.08
μg
l
−1. Coefficients of variation for intra- and interassay studies were 5.5 and 12.7%, respectively. Recovery of spiked samples showed acceptable values. Significant correlation was observed among sex, with higher values for women. Age also showed an influence on urinary Cd levels, being higher for individuals over 46 years. No correlation was found between either tabagism or alcoholic beverage intake and of urinary cadmium levels.
The present study is pioneer in analyzing the chemical composition of the essential oil from aerial parts of Turnera subulata Sm. and evaluates their antibacterial activity against a panel of ...drug-resistant strains of Staphylococcus aureus. The aerial parts were kiln-dried and then powdered in mechanical mill, and was subjected to hydrodistillation in a Clevenger-type apparatus. The components were analyzed using a mass spectrometrycoupled gas chromatography (GC-MS), and the identification of substances was performed by comparison of the mass spectra obtained with the mass spectra of the database of the GC-MS and retention indices . The essential oil was evaluated using the method of broth dilution at concentrations ranging from 3.125µg/mL to 3200µg/mL. It was possible to identify 45 substances (92.1%) of the essential oils, and the major components were trans-caryophyllene (6.7%), citronellol (5.6%), sphatulenol (5.3%), α-cadinol (4.3%), n-tricosano (4.3%), geraniol (4.1%) and trans-geranilacetone (3.7%), n-pentacosano (3.5%), globulol (3.4%), caryophyllene oxide (3.2%). The essential oil of T. subulata Sm. showed effective antibacterial activity for the various strains of S. aureus tested, with the MIC values between 25 µg/mL and 1600 µg/mL. The study of the essential oil of Turnera subulata Sm. showed that it consists of a complex mixture of several classes of compounds having the sesquiterpenes as major constituents followed by monoterpenes, and showed an antibacterial activity significant front the strains tested.
O presente estudo é pioneiro em analisar a composição química dos óleos essenciais das partes aéreas de Turnera subulata Sm. e sua atividade antibacteriana frente à Staphylococcus aureus resistentes a antibióticos. As partes aéreas da planta foram secas em estufa, pulverizadas em moinho mecânico e submetidas à hidrodestilaçao em aparato tipo Clevenger. A composição dos óleos essenciais foi analisada por cromatografia gasosa acoplada a espectrometria de massas (CG-EM), e a identificação realizada por comparação dos espectros de massas com a biblioteca do CG-EM e índices de retenção. A atividade antimicrobiana do óleo essencial foi avaliada usando o método de diluição em caldo, em concentrações que variaram de 3.125µg/mL to 3200µg/mL. Foi possível identificar 45 substâncias (92,1%) do óleo essencial, sendo os componentes majoritários: trans-cariofileno (6,7%), citronelol (5,6%), espatulenol (5,3%), α-cadinol (4,3%), n-tricosano (4,3%), geraniol (4,1%) e trans-geranilacetona (3,7%), n-pentacosano (3,5%), globulol (3,4%) e óxido de cariofileno (3,2%). O óleo essencial de T. subulata Sm. mostrou atividade antibacteriana eficaz para as várias cepas de S. aureus testadas, com valores de CIM entre 25 µg/mL e 1600 µg/mL. O estudo do óleo essencial de Turnera subulata Sm. evidenciou sua complexa mistura, contendo várias classes de substâncias, tendo os sesquiterpenos como constituintes majoritários seguido dos monoterpenos, e mostrou significativa atividade antibacteriana frente as cepas testadas.
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