[Diagnostic accuracy of digital phosphor plates using pseudo-color enhancement for detection of horizontal root fractures in single-rooted teeth]

If root fractures remain undetected, pulp necrosis will occur in 25% of cases leading to eventual tooth loss. The purpose of this study was to evaluate the diagnostic accuracy of digital phosphor plates using pseudo-color enhancement for detection of horizontal root fractures in single-rooted teeth. Eighty-two human single-rooted teeth were evaluated [41 with no horizontal fracture and 41 with horizontal fractures]. Digital intraoral imaging plate system. [Digora[registered sign] Optime PSP System, Soredex] was used to obtain 16-bit gray scale images. Five 16-bit images were obtained from each specimen and saved [one original and four with pseudo-color enhancement]. Four observers evaluated the images twice with a 2- week interval. Accuracy, positive predictive value [PPV], negative predictive value [NPV], specificity and sensitivity for each observer and each image group were calculated. The diagnostic sensitivities were not significantly different among the five images [P absolute=0.125, P complete=0.170]. But, statistically significant differences were found in the diagnostic specificity [P absolute=0.019, P complete=0.016] among the five views. Cool and Summer views had higher diagnostic specificity than Bone, Copper and Original views [P=0.025]. Kappa and Weighted Kappa values showed statistically significant differences for intra- and inter-observer reliability in the five views [P=0.032]. Both Cool and Summer views were suitable for detection of horizontal root fractures and had statistically significant differences with the original view

[Conventional and self-developing films in estimation of the working length]

Statement of Problem: Determining the appropriate Working Length [WL] is an important factor in the success of root canal therapy. Several methods are available for this purpose but radiography is the mostly used one

Purpose: The aim of this study was to compare the conventional and self -developing films with a Gold standard in estimation of the working length

Materials and Method: In this descriptive study, radiographs were obtained with conventional and self-developing films from 45 mesiobuccal maxillary molar root canals which were mounted on a phantom head. Conventional films were processed automatically and self-developing films manually in accordance with manufacturer's instructions. The radiographs were examined by three endodontologists and one oral and maxillofacial radiologist under doubleblind conditions. Actual working lengths were measured on each tooth [Gold standard] and then measurements from each film type were compared together and against the Gold Standard. The data were analyzed using t-test and paired t-test

Results: The average difference in WL between the conventional and self-developing films measured against the Gold standard was 0.33 mm and 0.14 mm, respectively. No significant difference was found between these two types of films and the Gold standard [p =0.06 and p =0.7, respectively]. Also, there was no significant difference between these two types of films for estimation of the working length [p =0.4]

Conclusion: Although there was no significant difference between these two types of films, the assessment shows that self-developing films produced more accurate results in estimation of the working length. It is concluded that in the absence of dark room and processing solutions, self-developing films can be suitably used instead of conventional films

Antibiotic resistance to third generation cephalosporins due to CTX-M-type extended-spectrum beta-lactamases in clinical isolates of Escherichia coli

Organisms producing CTX-M-beta-lactamase are emerging around the world as a source of resistance to oxyiminocephalosporins such as cefotaxime. However, the laboratory detection of these strains is not well defined. The aim of this study was to determine the presence and prevalence of known CTX-M-beta-lactamases genes in clinical isolates of Escherichia coli from hospitals of Tehran. During six months [September to February, 2006], 160 clinical isolates of Escherichia coli collected from three university hospitals of Tehran. Phenotypic screening and confirmation tests for ESBL detection was according to CLSI advised. All of the ESBL-producing isolates were examined by PCR for presence of bla CTX-M genes. Primary phenptypic tests revealed that 56.69% [n=89] of E. coli isolates produced ESBLs. In confirmatory tests by use of clavulanic acid, ESBL production were confirmed [P+C+] in 96.7% [n=86] of isolates with primary positive test. The presence of an ESBL was not confirmed [P+C-] in 3.3% [n=3] of the screen positive. Of all screen positive isolates, 34 [35.78%] were positive for bla CTX-M genes from the CTX-M-I group, indicating CTX-M-1-like beta-lactamases and Two [2.1%] were positive for bla CTX-M genes from the CTX-M-III group, indicating CTX-M-3-like beta-lactamases. The remainder 59 [62.2%] were negative for bla CTX-M genes. The levels of resistance to ceftazidim were remarkably varible among CTX-M producers. This study provides futher evidence of the global dissemination of CTX-M type ESBLs and emphasize the need for their epidemiological monitoring

Occult hepatitis B virus infection among blood donors with antibodies to hepatitis B core antigen

Diagnosis of hepatitis B is routinely based on of serological assay of hepatitis B surface antigen [HBsAg]. Occult hepatitis B virus [HBV] infection is generally defined as the detection of HBV -DNA in the serum or tissues of subjects who have negative test for HBsAg. Transmission of HBV infection has been documented from HBsAg negative, anti-HBc positive blood and organ donors. The aim of this study was to determine the rate of occult HBV infection among HBsAg negative and anti-HBc positive blood donors of Rafsanjan blood transfusion center. Sera from 270 healthy blood donors who were negative for both HBsAg and anti-HCV, were tested for anti-HBc antibodies by use of ELISA technique. The samples that were negative for HBsAg but positive for anti-HBc markers also examined for the presence of HBV-DNA by polymerase chain reaction [PCR]. Out of 270 HBsAg negative blood samples, 14 samples [5.18%] were positive for anti-HBc antibodies. HBV-DNA was detected in 4/14 [28.57%] of HBsAg negative and anti-HBc positive samples. Moreover, anti-HBs antibody was detected in 2/4 [50%] of HBV-DNA positive samples. These results indicated that HBV-DNA found in the majority of HBsAg negative and anti-HBc-positive donors. In addition, the present study recommend the incorporation of routine anti-HBc screening of blood as a surrogate marker of occult HBV infection to prevent some transfusion-transmitted HBV infections

[Lactobacillus as probiotic bacteria]

Introduction: Selected probiotic lactobacilli have inhibitory effect and therefore may be use as biological preservative, so, the aim of this study was to present some data on isolation, growth, antimicrobial activity, effect of pH, heat, and sensitivity to proteolytic enzymes of lactobacillus

Material and Methods: Isolation of lactic acid bacteria from sausage was done by using 1g of samples in MRS medium. Each isolate of lactobacillus species was identified by biochemical tests and comparison of their sugar fermentation pattern. Antibacterial activities was done by an agar spot, well diffusion and blank disk method. Stability of antibacterial activity was measured in boiling water and autoclaving for 15 min. Enzyme sensitivity of supernatant fluid and concentrated cell free culture after treatment with a-amylase, lysozyme and trypsin was determined

Results: The isolated bacteria were Lacto. plantarum, Lacto delbruekii, Lacto. acidophilus, Lacto. brevis. The isolated bacteria had strong activity against indicator strains. The antibacterial activity was stable at 100°C for 10 minutes and at 56°C for 30 minutes, but activity was lost after autoclaving. The maximum production of bacterocin was obtained at 25-30°C at pH 6.5

Discussion: If Lactobacilli that are used to induce sausage fermentation have antimicrobial activity with heat stable bacteriocin, these bacteria may be considered to be a healthy probiotic diet. Lactobacilli originally isolated from meat products are the best candidates as probiotic bacteria to improve the microbiological safety of these foods