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Showing 75 results for Specificity

B Goliaei, A Deizadji, A Rabbani,
Volume 5, Issue 1 (9-1991)

Two groups of antibodies against mouse resident alveolar and peritoneal macrophages have been raised individually in rabbits by immunization with whole cell suspensions of lavaged alveolar and peritoneal macrophages. The whole antisera reacted positively with neutrophils and lymphocytes. However, upon extensive absorptions with these cells the activity became restricted to macrophages. The immunoglobulins were purified up to 8 fold by repeated precipitations with saturated ammonium sulphate. The antibodies were labeled with fluorescein isothiocyanate and further used. The specificity of antibodies was confirmed by direct and indirect immunofluorescence and complement-dependent cytotoxicity. In the cytolysis of target cells in the presence of complement, the antibodies could lyse more than 80% of cells at dilutions as low as 1:512.
Mohammad Hossein Alimohammadian, Hasan Hakimi, Moradali Nikseresht,
Volume 7, Issue 1 (5-1993)

Cell-mediated immunity (CMI) plays an important role in resistance against leishmaniasis. Delayed-type hypersensitivity (DTH) reaction measured by skin testing is a practical method of evaluation of CMI and is used as an aid to diagnosis and for epidemiological assessment of exposure to leishmanial infection. Skin testing in leishmaniasis, generally known as Montenegro or leishmanin test, requires a standard antigen. At present no uniform and standard leishmanin is available for skin testing in leishmaniasis. The present work describes the preparation and testing of an antigen from Leishmania major using standard conditions. Three dilutions of this antigen were tested in recovered individuals in an endemic area in Iran. The results obtained showed that leishmanin preparation exhibited high specificity and sensitivity, and strong potency.
Gh R Asadikaram, Mj Rasaee, S Ale Agha, Gl Kumari, Pn Rao,
Volume 7, Issue 2 (8-1993)

Testosterone was measured using antibodies raised against testosterone II B-carboxymethyl ether bovine serum albmin (T-IIB-CME-BSA) and testosterone 3- O-carboxymethyl oxime-BSA as immunogen. The antibody produced in this study exhibits minimal cross reactivity with the structurally related steroids specially 5 dihydrotestosterone (5 DHD. This allows to ommit the clean up step and measure testosterone in female serum samples accurately with a high sensitivity, precision, and specificity. The coefficent of variation (CY), standard deviation (SD) and standard error of mean (SE) were all in acceptable ranges. Antibody-bound and free steroids were separated by addition of dextran coated charcoal. The method was applied to a set of clinical samples, the results of which are discussed in this communication. The assay was compared with the available imported kits using 125 I as tracer. The correlation coefficient obtained is calcualted to be r= 0.96, showing that the results obtained by these two methods are fully comparable and the assay may be replaced with the similar preparations imported from abroad.
M Rezaeian, Y Hamzavi,
Volume 7, Issue 3 (11-1993)

As there was not any previous comprehensive study on the serological tests for hepatic amebiasis in Iran, the indirect hemagglutination (IHA), indirect fluorescent antibody (IF A), and biocolored latex agglutination (BLA) tests were evaluated in the serodiagnosis of amebic liver abscess(ALA). For this purpose a total of 165 serum samples 18 of which were obtained from patients known to have ALA, were examined for Entamoeba histolytica antibodies. E. histolytica antigen used for IFA technique was prepared in the Intestinal Protozoa Laboratory, Protozoology Unit, School of Public Health, Tehran University of Medical Sciences. The results of the survey showed that the IHA and BLA were somewhat more sensitive than IFA in the serodiagnosis of ALA. The sensitivity, specificity, and positive and negative predictive value of these tests were compared
Ghr Omrani, Py Kumar, S Tabei, M Khoddami,
Volume 8, Issue 1 (5-1994)

377 patients with single thyroid nodule who clinically were candidates for surgery, were selected from the patients that referred to the clinics of endocrinology at Namazee Hospital, Shiraz Medical School. Fine needle aspiration (FNA) was carried out without performing thyroid scan and the results were compared with histology obtained by surgery to establish its accuracy in our center. which is an area of endemic goiter. 72% were benign confirmed by surgery, 17% malignant(of which two cases were colloid goiter) and II % (42 cases) were suspicious: of these 42 suspicious cases, 28.5% were follicular carcinoma and the rest were benign. In this study sensitivity and specificity of FNA were 91 % and 97%, respectively. In conclusion, although our area is an endemic goiter area, the accuracy of FNA is comparable to iodine sufficient areas.
M. Mehdi Aslani, Reza Gharagozloo,
Volume 9, Issue 3 (10-1995)

In a clinical trial a new pyrrolidonyl-β-naphthylamide (PYR) hydrolysis test was compared with the bacitracin disk susceptibility test for accuracy in the presumptive identification of group A streptococci (GAS). Among 128 isolates of beta-hemolytic streptococci 93 group A isolates were found. The sensitivity of the PYR and bacitracin tests were similar (98.9%), but the bacitracin test had a lower specificity (80%) than the PYR test (100%). The efficiency of the PYR and bacitracin test were 99.2% and 93.7%, respectively. All bacitracin tests were performed on subcultures of the isolates from the primary plate, whereas PYR testing was performed on colonies from the primary plate. This shortened the turnaround time for the PYR test compared to the bacitracin test by at least 24 hours.
M Vodjgani, F Nassiri Zadeh, J Hadjati, M Akbarlan,
Volume 11, Issue 1 (5-1997)

Antineutrophil cytoplasmic autoantibodies (ANCA) were first described in patients with necrotizing glomerulonephritis. The original observation passed unnoticed until an association was made between ANCA and active Wegener's granulomatosis. Since then, tremendous progress has been made in elucidating the association between ANCA subtypes and clinicopathologic syndromes, and the potential pathologic role of ANCA in vascular inflammation. The gold standard method for ANCA detection is indirect immunofluorescence (IIF) microscopy of ethanol-fixed cells. By this technique two general patterns of ANCA, acytoplasmic pattern (c-ANCA) and a perinuclear pattern (P-ANCA) can be identifed. Recently some reports have been published concerning the prevalence, subtypes, role and specificity of ANCA.ln this study we searched for ANCA prevalence, subtypes, and its relationship with disease activity in SLE patients by IIF technique. Our results showed that all normal subjects were ANCA negative, while at least 50% of patients were ANCA positive (majority c-ANCA type). Statistical analysis revealed that there is no correlation between the presence of ANCA and disease activity (p<0.01).
Seyed Abbas Bazargan, Bahman Tabaraie, Bahram Fatollahzadeh, Nasrin Moazzami,
Volume 11, Issue 2 (8-1997)

Mono-specific antisera against Vibrio cholera Ogawa NIH-43 and Vibrio cholera Inaba 35-A3 were prepared from rabbit hyperimmune sera by absorbing against a heterologous strain. Using ammonium sulphate precipitation procedure, gamma globulins were purified and concentrated. To visualize antigen-antibody reaction, gamma globulins were conjugated to Staphylococcus aureus cowan-l (NCTC: 8325) in the presence of 50% propanol- 1. Then equal suspensions of each conjugated serum were mixed to prepare V. cholera. Rectal swab samples from suspected choleric patients were inoculated in bile peptone broth for 5 hours at 37°C. One drop of each sample was mixed with one drop of VBCR and coagglutination was read at 2-3 minutes. The results were compared with corresponding results obtained from conventional culture methods. Specificity and sensitivity of coagglutination tests were found to be 98.03% and 95.1 %, respectively. Regarding the fact that rapid diagnosis of cholera is vital to save patients, our study reveals that coagglutination test, using bivalent mono-specific antisera, can be considered as a simple, rapid and reliable test to detect V. cholera-O 1 from stool samples of suspected patients.
Mehdi Keshmiri, Mojtaba Hashemzadeh,
Volume 11, Issue 3 (11-1997)

Light's criteria (protein and LDH) have been used to the present to differentiate exudative pleural effusion from transudative. This is both time consuming and relatively more expensive as compared to measuring cholesterol. During 1992-1993, a prospective study on 70 patients with effusion was carried out measuring fasting LDH, protein, cholesterol, alkaline phosphatase and glucose. All patients had their underlying disease diagnosed then Light's criteria was compared to cholesterol using Wilcoxon's test and Student's t-test. Our findings showed taking a value of pleural cholesterol>55 mg/dL and pleural/serum cholesterol > 0.3 to define exudative effusion resulted in less erroneous classification with a sensitivity of 93%, a specificity of 100%, a positive predictive value (PPV) of 100% and an accuracy of 95.2%. Using Light's criteria gave a sensitivity of 95%, a specificity of 95%, a PPV of 97.6% and an accuracy of 95.2%. Using cholesterol in differentiating exudate from transudate was especially useful in patients with CH.F. who received diuretics. Therefore, using cholesterol to differentiate exudative from transudative pleural effusion is more cost-effective and just as useful as Light's criteria
M Saberi-Firouzi, F Kaffashian, E Hayati, Aa Ghaderi, H Keshavarz, S Arshadi, C Arshadi, Mse Sotudehmaram, Ms Massarrat, Ma Ghalambor,
Volume 12, Issue 2 (8-1998)

In order to assess the prevalence of Echinococcus granulosus (EO) infection (hydatidosis) in nomadic tribes of southern Iran, 1000 individuals from a total population of 1 12,519 were selected by randomized single blind cluster sampling method and studied from 1994- 1995. The study included: ( l ) a physical examination by a gastroenterologist, (2) abdominal ultrasonography (US), and (3) detection of anti-EO-antibodies (EOA) by an enzyme-linked immunosorbent assay (ELISA) and counterimmunoelectrophoresis (CIE). The statistically significant prevalences were: US: 1.8%, eIE: 6.8%, and ELISA, 13.7%. The rate of infection varied with age, sex, education, occupation, life style, geographical location of tribal subgroups and the frequency of contact with dogs and cattle. The power of agreement between a combination of each two methods were significant as determined by kappa statistics method. The results obtained indicated that a combination of ELISA and CIE was the most reliable method with a high sensitivity and specificity.
Saeed Oraii, Majid Maleki, Mehrnoosh Minooil, Parivash Kafaii, Mahmood Eftekharzadeh,
Volume 12, Issue 4 (2-1999)

Sublingual nitroglycerin (TNG) has been introduced as a promising provocative agent for tilt table testing, but it has not been compared directly with the standard isoproterenol (ISO) infusion test previously. We tried to assess the diagnostic value and safety of TNG tilt testing as compared with ISO infusion in patients with unexplained syncope. TNG and ISO tilt tests were performed in two successive days on a random basis for both cases and controls. 65 consecutive patients with unexplained syncope after thorough work-up and 20 healthy volunteers were recruited into the study. Positive responses were observed in 20 patients (31 %) during the passive phase, 25 (55% of cases or 38% of total) during the TNG phase and 26 (58% or40% of total) during the ISO phase. In the control group, positive responses during the passive, TNG and ISO phases occurred in 1,1 and 2 cases, respectively. The sensitivity and specificity of the tests can be summarized as 69% and 90% respectively for the TNG test versus 71 % and 85% respectively for the ISO test. Owing to discordant responses in 75% of the cases, the sequential use of the tests (if one is negative) would increase the sensitivity to 89% while decreasing the specificity slightly (to 80%). Side effects were also less frequent with TNG. We conclude that sublingual TNG testing is an effective and safe alternative to the ISO infusion test and can be used as a complementary test.
Tahereh Shokohi, Julie C. Silver,
Volume 13, Issue 1 (5-1999)

Invasive aspergillosis (1 is a life-threatening condition in immunocompromised patients. An early diagnosis is of great importance because early treatment may resolve this potentially fatal infection. Recently, the polymerase chain reaction (PCR) has been used successfully in detecting specific DNA of several pathogen. In this study, nested PCR was used to detect DNA specific for A!.pergiflus species isolated from bronchoalveolar lavage (BAL) fluid from patients with TA. In single PCR using the outer primers a specific 384-bp fragment was amplified. Similarly, y nested PCR with inner primers, a 357-bp fragment was amplified with DNA from Aspergillus fumigatus but not from the other microorganisms. The Southern blot hybridizations confirm the specificity of the PCR procedure for A. fumigatus using the cloned 374-bp PCR product probe. In conclusion, the nested PCR method appears to be quite rapid and specific.
Behzad Einollahi, Mohammadreza Khatami, Mahboob Lesanpezeshki, Pejman Bakhtiari, Violet Amirjalali, Ahmad Firouzan,
Volume 13, Issue 3 (11-1999)

A perplexing issue in diagnosing the cause of renal allograft dysfunction is differentiation between rejection----the most common cause--and many other possibilities that have detrimental effects on graft function. This study was designed to determine whether technetium - 99m sulfur colloid (TSC) accumulation could predict graft rejection. We prospectively studied 54 episodes of allograft dysfunction in 53 kidney transplant recipients who had undergone TSC scintiscanning and graft biopsy, within one week of evidence of allograft dysfunction. Visual analysis of TSC uptake was done by comparing allograft uptake with that of the fifth lumbar vertebra (L5) marrow. A 3+ result meant that allograft uptake was greater than L5 marrow uptake 2+, allograft uptake was the same as L5 marrow uptake 1+, less than and 0, no allograft uptake. Transplant accumulation of 􀁀2+ was considered consistent with rejection (p=0.01). Allotransplant biopsies were interpreted based on the Banff Working Classification and rejection was noted in 45 of 54 renal biopsies. 42 of 45 biopsy -proven rejection episodes had ≥2+ graft uptake. This nuclear medicine technique has a sensitivity of 93.3%, specificity of 44.4%, a positive predictive value of 89.3%, a negative value of 57.1 % and an efficiency of 83.3% in the diagnosis of renal allograft rejection.
H Tajerzadeh, S Sadray,
Volume 13, Issue 3 (11-1999)

A simple, rapid and sensitive HPLC method for the determination of theophylline (T) in human serum has been developed. An isocratic system consisting of a /-l Bondapak C18 column, mobile phase of methanol, phosphate buffer (22:78, pH=4.5), and a flow rate of 1.4 mL/min was used. The eluent was detected by UV at 275 nm at room temperature. 8-Chlorotheophylline (8-CT) was used as an internal standard. The serum samples deproteinated by methanol containing 8-CT and the supernatant was injected into the HPLC system. The retention times of 5.7 and 8.1 min were found for T and 8-CT, respectively. The linearity was checked in the range of 0.2- 30 µg/mL. Relative standard deviation for both inter-day and intra-day precision analysis was less than 5%. No interference was observed from endogenous serum components. Specificity was shown against some commonly co-administered drugs. Simple and fast sample preparation, small sample volume (250 µL), precision, reproducibility, specificity, sensitivity and high percentage recovery (98 %) make the method to be practically useful for T monitoring in asthmatic patients.
Bijan Khademi, Behrooz Gandomi,
Volume 14, Issue 3 (11-2000)

In an attempt to determine the diagnostic value of FNA biopsy of head and neck masses, we reviewed FNAs performed on target lesions of the head and neck in1 59 patients who subsequently underwent surgery in Khalili hospital dur-. ing a 55 month period. Results ofFNAs were compared with postsurgical histologic diagnoses. These 159 cases were broken down into four categories: thyroid masses 34 , lymph nodes 3 6, salivary gland masses 58 , and masses not classified in the first three categories 31 . Values of specificity, sensitivity, positive predictive vlaue (in diagnosing malignancy) and negative predictive value (in diagnosis of benign disease) were calculated for each category and for all masses. Overall, we obtained a sensitivity of 77%, specificity of 94%, positive predictive value of 84% and negative predictive value of90% that was comparable with several other studies performed elsewhere, except that our elevated numbers of false negative in the salivary gland category lowered the sensitivity of FNA in this category to 57% and the overall sensitivity to 77%. The other disparity between our results and those of other studies I is our slightly elevated false negative rate (6.9%), overall sensitivity.
F Fotohi, Mh Roustaee, H Soleimangahi, Ar Khabiri, M Malekane, F Sabahi,
Volume 15, Issue 1 (5-2001)

Measles is one of the most contagious human diseases. Although mass vaccination programs have reduced the incidence of this disease, measles is still an important cause of morbidity and mortality among children in developing countries. Therefore the use of sensitive techniques to evaluate vaccine efficacy and level of immunity among members of susceptible communities is crucial. Serum neutralization test (SNT) and Dot immunoassay (DIA) are among the best methods utilized for evaluating measles virus antibodies. In this study, DIA was applied for detection and titration of measles virus antibodies. This test was developed for the first time in Iran in the Virology Department of the School of Medical Sciences, Tarbiat Modarres University. Viral antigen was first prepared and titrated. Then human IgG was isolated by affinity chromatography. Anti-human immunoglobulin was prepared by immunizing rabbits with human IgG and was later conjugated with peroxidase. DIA was applied using these reagents. The results indicated that the specificity and sensitivity of DIA in comparison with SNT was 96% and 89%, respectively. This study demonstrated that DIA is a rapid and simple test which can be applied for the detection of mass immunity against the measles virus.
Z Zamani, M Assmar, N Pyazak, K Wafaie, M Assadian, A Amirkhani,
Volume 15, Issue 1 (5-2001)

Hydatid cyst fluid has been used as a source of antigen for the serodiagnosis of Echinococcus granulosus infection. Due to cross-reactions with antigens shared by other helminthes, the specific antigen from hydatid cyst fluid was purified by many workers. We used a relatively simple technique for purification of specific antigen from sheep hydatid cyst fluid. Isopycnic ultracentrifugation with 30% KEr was used followed by SDS-PAGE to check the purity of the antigen. The antigen was of 48 kDa and used in ELISA and IRA with high sensitivity and specificity.
T Bamdad, Mh Rodstai, H Solimandjahi, M Malekaneh,
Volume 15, Issue 3 (11-2001)

A dot immunobinding assay ( DIA) was used for a quantitative and qualitative assay of rubella antibody. Purified antigen and conjugated anti-human immunoglobulin (RAHlg) were prepared. Nitrocellulose paper dotted with the antigen was added to serially diluted sera or blood samples. The reacting antibodies were visualized by a peroxidase system. Development of a colored insoluble substrate was taken as a positive result. The adapted DIA was applied to test 105 serum samples. The sensitivity and specificity and immune titer of DIA were compared with hemagglutination inhibition (HI) test.
Z Amirghofran, Ak Sheikhi,
Volume 15, Issue 4 (2-2002)

Alpha-fetoprotein (AFP), a serum glycoprotein belonging to the onco-developmental proteins group, serves as a marker both in cancer research and in studies concerning fetal development and fetal pathophysiology. Monoclonal anti-AFP antibodies are essential reagents in developing appropriate techniques for measurement of this protein. In this study, in order to produce anti-AFP monoclonal antibody (mAb), AFP was partially purified from cord sera using two-step ion-exchange chromatography on DEAE-cellulose with a final recovery of about 570µg. MAbs against this preparation was raised by hybridoma technology using Ag8.653 mouse myeloma cells as the fusion partner. Hybridomas appeared in 10% (30/300) of culture wells and of these 2 clones were found to be positive for anti-AFP production. In western blot analysis a 70 kD band from dead fetus serum-but not adult serum-was stained by both mAbs. A sandwich ELISA technique using polyclonal antisera on one side and mAbs on the other side was employed to plot dose response curves. The positive dose dependent reactivity of the mAbs with standard AFP and other AFP containing samples and the negative reaction with normal adult sera lacking AFP showed the specificity of the mAbs for AFP.
H Vahhab Aghai, P Pasalar, I Najafi, M Kadkhodaee,
Volume 16, Issue 1 (5-2002)

Cystatin C is a 13 KD basic protein that is a member of the cystatin superfamily of cysteine protease inhibitors. The cystatin C gene seems to be a house keeping gene, which is compatible with a stable production rate of cystatin C by most cells. This protein is freely filtered through the glomerulus and almost completely reabsorbed and catabolized by proximal tubular cells. Because of these characteristics cystatin C is assumed to be a better marker of glomerular filtration rate than other markers. 115 new cases of renal disease aged between 14 and 88 years and 121 healthy subjects, aged between 11 and 78 years were studied. In all of the subjects serum cystatin C and creatinine were determined and creatinine clearance was determined only in patients. Cystatin C was determined by a particle-enhanced turbidimetric assay and creatinine was measured by Jaffe's method. In addition, to assess the diagnostic efficiency of serum cystatin C in comparison to that of serum creatinine and creatinine clearance in predicting changes in GFR, we performed Tc99m - DTPA clearance on 53 subjects including controls and patients. A linear relationship was found between Tc99m - DTPA clearance and 11 serum cystatin C (r= 0.712, p-value <0.001), l/serum creatinine (r= 0.709, pvalue< 0.001) and creatinine clearance (r= 0.777, p- value <0.001). Diagnostic accuracy in the identification of reduced GFR measured as area under the receiver-operating characteristic plot was 0.878±0.050 (Mean±SE) for cystatin C, 0.866±0.051 for creatinine and 0.866±0.051 for creatinine clearance. The serum cystatin C reference values (mean±1.96 SD) determined was 0.83 - 0.88 mg/L. A cutoff cystatin C concentration of 0.82 mg/L had 92% sensitivity and 79% specificity for detecting abnormal GFR. There was no significant correlation between cystatin C and age (p- value <0.219) and weight (p- value <0.193). This study demonstrates that serum cystatin C has an increased diagnostic accuracy for reduced GFR when compared with serum creatinine and creatinine clearance. Hence, cystatin C seems to be an alternative for the estimation of GFR.

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