[ effect of smear layer removal on permeability of dentinal tubules in human by dye penetration method]

The effect of smear layer on dentinal tubules is remarkable in endodontic treatments. The aim of this study was measuring the range of dye penetration in dentinal tubules with and without smear layer. Thirty extracted human teeth used in this study. At first, segments e prepared with 5 mm length from each tooth's root and then their canals widened by a 1/4 mm diameter bur, so that the smear layer appeared. The external, superior and inferior surfaces of the segments covered by 2 layers of nail varnish. The segments divided to 2 groups of 15 samples. The first group samples immersed in 17% EDTA for 2 minutes and then in 5.25% NaOCl for 20 minutes to remove the smear layer. After that the samples immersed in 2% basic fushin for 24 hours, the second group samples immersed in 2% basic fushin without removing the smear layer. After water rinse, all samples sectioned horizontally from middle of the root and photographs was taken of each samples surfaces. After transmitting the photographs to a computer, the percentage of the dye penetration into dentinal tubules of each sample calculated by Photoshop software. Due to results, the range of dye penetration in dentine tubules of the teeth with and without smear layer had no statistically significant difference [P-Value=0.120]. According to the result, smear layer removal have no effect on dentin permeability to dye penetration and dentin sclerosis is an important factor in this subject. Performing studies on the teeth with certain age and using other methods such as microbial permeability evaluation are needed

[Comparison of blood culture with acridine orange stained smear of buffy coat in diagnosis of septicemia]

Different methods, with varying degrees of specificity and/or sensitivity, are used for diagnosis of sepsis. The present study was designed to determine and compare the sensitivity and specificity of blood culture with Acridine Orange [A.O.] stained smear of buffy coat in patients with sepsis. This research was conducted on 101 hospitalized patients with clinical signs and symptoms compatible with sepsis. Blood cultures were taken and A.O. staining was done on blood samples of all patients. Blood cultures were positive in 20 [19.8%] patients. Sensitivity and specificity of blood cultures were 26% and 92% respectively. A.O. stained smears of buffy coats were positive in 54 [54.5%] patients. Sensitivity and specificity of A.O. Stained smears of buffy coats were 83% and 100% respectively. A.O. stained smear of buffy coat, as a diagnostic test of sepsis is more sensitive than blood culture. In addition, it takes less than one hour to be performed, as compared to blood cultures that give results in 2-3 days

[Colonization rate of intravascular catheters and catheter related bacteremia in neonatal intensive care unit of Qods hospital, Qazvin [2005]

Peripheral intravenous catheters are increasingly used in neonatal intensive care unit [NICU] to administer intravenous fluids, blood products, drugs and nutrition. Catheter infection is associated with increased morbidity, mortality, and duration of hospital stay. To determine colonization rate of intravascular [IV] catheters and catheter related bactermia in NICU of Qods hospital. This was a descriptive study carried out on 100 infants who catheters were removed for any reason. A length of 3 cm from the catheter tip was cut aseptically and placed in thioglycolate media. In case of any growth within the next 7 days, subcultures on blood agar and MC agar media were performed followed by bacterial identification. Drug susceptibility profiles of isolated bacteria were detected according to standard methods. Before catheter removal, blood sample from each infant, was taken for culture, microbiological identification and susceptibility assay. Of 100 catheter tips, 35 [35%] samples produced positive cultures among those 19 cases [52%] identified as coagulase negative staphylococci [CNS]. Positive blood cultures were found in samples of 7 patients [7%], all from catheters colonized with bacteria, and identified as CNS [4 samples] and coagulase positive staphylococcus [3 samples]. Among the CNS isolated from catheters, the highest resistance [100%] was related to ampicillin and Oxicillin and the lowest [18%] resistance associated with vancomycin. Application of intravascular catheters in neonates should be accompanied with great attention in making a balance between the need for vascular access and the risk of bacteremia and thus, adequate control and rigorous preventive measures must be established when a vascular access is a necessity

Comparison of urine culture and urine dipstick analysis in diagnosis of urinary tract infection

Urine dipstick is a useful and commonly used test because of its rapidity and low cost; however its diagnostic accuracy is debatable. This research was carried out to determine sensitivity, specificity and positive and negative predictive values of nitrite [NIT] and leukocyte esterase [LE] testing in relation to urine culture. This research was conducted on 100 hospitalized patients with clinical signs and symptoms compatible with urinary tract infections [UTI]]. Urine culture and dipstick tests were carried out on urine samples of all patients. Urinalysis LE and NIT studies were performed in fresh and uncentrifuged urine by using a manual urine analyzer [rapignost, Co. Marburg, Germany]. The urine culture was considered as gold standard. Urine cultures were positive in 75 [75%] patients. Dipstick tests of urine were positive in 79[79%] patients. Sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] of Dipstick test were 76%, 12%, 72% and 14% respectively. Although dipstick test of LE and NIT can avoid a large part of the cost incurred by urine culture, any method of urine screen [LE and NIT] shouldn't be substituted for a urine culture in the symptomatic patients in childhood

[Comparison of urine cultures and gram stained smears of urine in diagnosis of urinary tract infections]

Different methods are used for diagnosis of urinary tract infections [UTI], however, they have different specificity, sensitivity and time consuming procedures. To evaluate and comparing the urine culture results with gram stained smears of urine in diagnosis of urinary tract infections. This research was conducted on 100 hospitalized patients with clinical signs and symptoms compatible with UTI. Urine cultures and gram staining were performed on urine samples of all patients. Urine culture was positive in 75 [75%] of patients. Gram stained smears on urine sediments were positive in 68 [68%] of patients. Sensitivity, specificity and positive predictive value of gram staining were 85%, 84% and 94% respectively. Gram stained smears of urine, as a diagnostic assay for UTI, is not as sensitive as urine cultures, but it takes only a few minutes to be performed, comparing with urine culture which takes several days

Comparison of blood cultures and endotoxin measurements in diagnosis of gram negative bacterial infections

Background: Gram negative bacterial infections continue to cause mortality due to unavailability of new methods for rapid diagnosis and appropriate treatment

Objective: To evaluate and compare blood culture results with endotoxin measurements in diagnosis of gram negative bacterial infections

Methods: This research was conducted on 100 hospitalized patients with clinical signs and symptoms compatible with septicemia. Blood cultures and endotoxin measurements [limulus amebocyte lysate, LAL test] were carried out on blood samples of all patients

Findings: Blood cultures were positive in 16 [16%] patients. Sensitivity and specificity of blood cultures were 18% and 100%, respectively. LAL tests were positive in 20 [20%] patients. Sensitivity and specificity of LAL test were 100% and 96% respectively

Conclusion: LAL test as a diagnostic assay for gram negative bacterial infections is more sensitive than blood culture. In addition, it takes only a few minutes to be performed, comparing blood culture that takes days