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PubMed1998

[Contact allergy to eyedrops containing beta-blockers].

In six patients (4 women aged 80, 62, 43 and 52 years and 2 men aged 58 and 51 years), who used eyedrops containing beta-blockers for the treatment of glaucoma, allergic contact dermatitis of the eyelids was diagnosed. Three were allergic to metipranolol, 2 to levobunolol and 1 to timolol. In literature, less than 50 cases of hypersensitivity to beta-blockers in eye medication have been reported. There are, however, reasons to assume that sensitization is more frequent: (a) not all patients are referred by the ophthalmologist to the dermatologist; (b) false-negative reactions to patch tests with the commercial preparations and with beta-blockers are not infrequent; (c) they are not routinely tested because beta-blockers are difficult to obtain in pure form; (d) cross-reactions with other beta-blockers are infrequent, and changing to another preparation therefore usually solves the clinical problem. Nevertheless it is advisable to test a battery of beta-blockers (befunolol, levobunolol, metipranolol, timolol) in allergic patients. A test preparation of 2% in water or 3%-10% in petrolatum may be suitable. Control testing in non-exposed individuals is necessary to exclude irritation reactions.

Adrenergic beta-Antagonists↗
PubMed1988

Comparison of pepsin-digestion and enzyme-linked immunosorbent assay for the diagnosis of trichinosis in swine.

Comparison of parasitological and serological diagnosis of trichinosis in swine was carried out on 36 pigs given 15,400 infective larvae each by gavage. Circulating eosinophil levels were determined and sera were examined by enzyme-linked immunosorbent assay for anti-Trichinella antibodies. Two pigs were killed per day from days 15 to 29 postinfection. Muscle was examined by pepsin-digestion and comparable tissue was fed to a rat. Eosinophil counts increased at about day 6 and reached peak levels about day 25 postinfection and returned to approximate preinfection levels about two months postinfection in those pigs still in the study. Infective larvae were recovered from all pigs killed at greater than or equal to 18 days postinfection. Using the criterion of 5 x mean optical density readings of negative sera as positive, seroconversion occurred between days 19 and 26 postinfection. Use of a lower criterion of 3 x mean optical density readings of negative sera resulted in only three of 30 pigs killed greater than or equal to 18 days postinfection seroconverting less than or equal to 18 days postinfection, when infective larvae were first recovered in the musculature. In pigs, even in those heavily infected, there is a lag between the period that trichinae in musculature become infective and development of antibodies as detected by enzyme-linked immunosorbent assay which results in false negative reactions in many animals. This study demonstrated that the enzyme-linked immunosorbent assay using an excretory-secretory antigen should not be used to certify pork or pork products free of infective Trichinella larvae or safe for human consumption.

Animals↗
PubMed2005

Sestamibi technetium-99m brain single-photon emission computed tomography to identify recurrent glioma in adults: 201 studies.

OBJECT: In the follow-up of treated gliomas, CT and MRI can often not differentiate radionecrosis from recurrent tumor. The aim of this study was to assess the interest of functional imaging with (99m)Tc-MIBI SPECT in a large series of 201 examinations. METHOD: MIBI SPECT were performed in 81 patients treated for brain gliomas. A MIBI uptake index was computed as the ratio of counts in the lesion to counts in the controlateral region. SPECT was compared to stereotactic biopsy in 14 cases, or in the others cases to imaging evolution or clinical course at 6 months after the last tomoscintigraphy Two hundred and one tomoscintigraphies were performed. One hundred and two scans were true positive, 82 scans were true negative. Six scans were false positive (corresponding to 3 patients): 2 patients with an inflammatory reaction after radiosurgery, 1 with no explanation up to now. Eleven scans were false negative (5 patients): 1 patient with a deep peri-ventricular lesion, 2 patients with no contrast enhancement on MRI, 2 patients with a temporal tumor. The sensitivity for tumor recurrence was 90%, specificity 91.5% and accuracy 90.5%. We studied separately low and high grade glioma: sensitivity for tumor recurrence was respectively 91% and 89%, specificity 100% and 83% and accuracy 95% and 87%. MIBI SPECT allowed the diagnose of anaplasic degenerence of low grade sometimes earlier than clinical (5 cases) or MRI signs (7 cases). CONCLUSIONS: Our results confirm the usefullness of MIBI SPECT in the follow-up of treated gliomas for the differential diagnosis between radiation necrosis and tumor recurrence.

Adult↗
PubMed1987

Failure to detect hydrogen-sulphide production in lactose/sucrose-fermenting Enterobacteriaceae, using triple sugar iron agar.

Triple Sugar Iron agar failed to detect hydrogen sulphide in 44 out of 69 hydrogen-sulphide producing strains of Enterobacteriaceae, which at the same time fermented lactose and/or sucrose. The species involved were Salmonella typhi, Salmonella enteritidis, Citrobacter freundii, Escherichia coli, and Proteus vulgaris. By contrast, no false-negative reactions were observed in 74 strains, which fermented neither lactose nor sucrose. Failure to detect hydrogen sulphide was probably due to acidification of the medium following the fermentation of carbohydrates. A medium without carbohydrates is preferable in diagnostic situations where hydrogen-sulphide detection is of great importance.

Citrobacter↗
PubMed1986

Effect of substrate on indirect immunofluorescence tests for intercellular and basement membrane zone antibodies.

The effect of substrate on the result of indirect immunofluorescence tests for intercellular and basement membrane zone antibodies was examined by testing concurrently 288 human sera on the three substrates used most commonly for this test, that is, monkey and guinea pig esophagus and normal human skin. Seventy-five sera had intercellular antibodies and 56 had basement membrane zone antibodies. The substrate influenced the results of 41% of assays for intercellular and 56% of those for basement membrane zone antibodies. Thirty-one percent of intercellular and 38% of basement membrane zone antibodies failed to react to one or more than one substrate, leading to false-negative reactions. In an additional 10% to 12% of sera, the titer of the reaction was influenced by the substrate. These results indicate that the substrate used has a major impact on the result of indirect immunofluorescence tests for antibodies to skin. The best overall single substrate was monkey esophagus, but optimal results were obtained when both monkey and guinea pig esophagus were used.

Animals↗
PubMed1989

Eliminating unnecessary urine microscopy. Results and performance characteristics of an algorithm based on chemical reagent strip testing.

The ability of a urinalysis reagent strip to predict the presence of formed elements in the sediment was evaluated. The sensitivity of individual biochemical analytes varies from 0.51 to 0.85; however, the combined sensitivity of positive reactions for either protein, nitrite, leukocyte esterase, and/or hemoglobin is 0.95. Leukocyte esterase activity becomes detectable at a concentration of 15 white blood cells per high-power field (WBCs/HPF). Proteinuria is nonspecifically related to pyuria and detects a minimum concentration of 6 WBCs/HPF, and the hemoglobin reaction detects 6 red blood cells/HPF. Most false negative reactions are associated with bacteriuria. A positive chemical reagent strip test can be safely and effectively used as a prerequisite for routine urine microscopic examination.

Adolescent↗
PubMed1994

Rapid identification of Candida albicans by using Albicans ID and fluoroplate agar plates.

Two commercially available agar media, Albicans ID and Fluoroplate, that use a chromogenic or a fluorogenic substrate for the detection and identification of Candida albicans were evaluated. From 1,006 clinical samples containing 723 yeast strains, 352 C. albicans strains were detected with either of the two media. The sensitivity of each of the two media was 93.8% and the specificity was 98.6%, with five false-positive reactions for Candida tropicalis and no false-negative reactions.

Agar↗
PubMed2001

[Rapid urease test].

The rapid urease test is a simple, sensitive, and highly specific test that enables the endoscopist to diagnose Helicobacter pylori infection in the endoscopy room. Determination of the infection status of Helicobacter pylori by biopsies from the gastric body had a significantly higher sensitivity than antral biopsies. A false-negative reaction by rapid urease test occurred the use of antibiotics (correlates with clearance of the bacteria) and the use of proton pump inhibitor or a part of mucosal protective agents(correlates urease inhibitory effect) and in the case of non-urease producing Helicobacter pylori. The rapid urease test satisfactory overall sensitivity before eradication treatment. However, the sensitivity of these rapid urease tests was lower after eradication than before eradication.

Clinical Enzyme Tests↗
PubMed1991

Evaluation of a 'dipstick' immunoassay to detect cysticercosis in experimentally infected cattle.

A 'dipstick' immunoassay for bovine cysticercosis, using an antigen isolated from Taenia hydatigena cyst fluid, was evaluated in cattle experimentally infected with Taenia saginata. The assay correctly identified six out of seven infected cattle, including an animal in which only 12 living cysticerci were found. Cattle became seropositive as early as 3 weeks post-infection. A false-negative reaction was found for one very lightly infected animal, from which only four living cysticerci were recovered at necropsy. The assay was also used to detect circulating antibodies in experimentally infected cattle before and after therapeutic treatment with anthelminthics. The results suggest that praziquantel-treated animals gradually revert to being seronegative after the cysticerci are killed.

Animals↗
PubMed1981

Detection of cryptococcal antigen. Comparison of two latex agglutination tests.

The detection of cryptococcal antigen by means of the agglutination of antibody-coated latex particles is an important aid in the diagnosis of cryptococcosis. A commercially available latex agglutination test (IBL kit) was compared with the latex agglutination test from the Center for Disease Control in regard to sensitivity, specificity, and height of antigen titer. Over a 13-month period, 335 specimens were tested with both kits. There was one false-positive reaction with both kits (0.4%) and one false-negative reaction only with the CDC kit, among 18 patients who had meningitis or disseminated infection due to Cryptococcus neoformans. Sera from patients who had localized pulmonary cryptococcosis showed negative results with both kits. The antigen titers measured by the two kits were the same or within two dilutions in 22 of 26 specimens of cerebrospinal fluid or serum from patients who had proved cryptococcosis. Overall, the IBL kit compared favorably with the CDC kit for the detection of cryptococcal antigen in cerebrospinal fluid or serum.

Antigens, Fungal↗
PubMed1981

Failure of the most-probable-number technique to detect coliforms in drinking water and raw water supplies.

A procedure was developed to detect false-negative reactions (interference) in the standard most-probable-number (S-MPN) technique for coliform enumeration of untreated surface water and potable water supplies. This modified MPN (M-MPN) procedure allowed a quantitative assessment of the interference with coliform detection in untreated surface water and potable water supplies. Coliform interference was found to occur in the presumptive, confirmed, and completed tests of the S-MPN technique. When coliforms were present, interference with their detection occurred in over 80% of the samples. The inferior nature of the S-MPN was revealed by the 100% increase in the incidence of completed coliform-positive drinking water samples obtained with the M-MPN technique. The M-MPN procedure was also superior to the standard membrane filter technique. Eight different species of coliforms were recovered from false-negative tests, including Citrobacter, Enterobacter, Klebsiella, and Escherichia coli (in decreasing order of occurrence). The use of standard MPN techniques for monitoring potable water supplies may lead to a false security that the drinking water supply is potable, i.e., free from indicator bacteria.

Bacteriological Techniques↗
PubMed1996

False-negative results in anti-HLA antibody detection by Sangstat ELISA: complement dependent cytotoxicity is not yet obsolete.

Although ELISA on purified HLA molecules for detecting anti-HLA antibody (P-S ELISA) does detect some antibodies previously missed by the conventional complement dependent cytotoxicity method (C Cytotox), HLA ELISA should not fail to detect antibodies already detected by the conventional reference method to be able to make C Cytotox obsolete and to replace it in routine testing. Among 40 selected sera, 8 false-negative reactions were observed in P-S ELISA. These sera were reanalyzed blind in two laboratories and found to contain non-IgM, warm anti- HLA antibodies. These antibodies were directed in 4 cases against an HLA molecule expressed on a kidney transplant previously rejected by the subject. These antibodies, if missed, would have been potentially harmful in kidney transplantation. Thus P-S ELISA can't yet replace C Cytotox in routine anti-HLA class I detection. The cost/benefit ratio of P-S ELISA as a second-line test remains to be investigated.

Antibodies↗
PubMedDate not supplied

Autoimmune hemolytic anemia associated exclusively with IgA of Rh specificity.

A nine-year-old boy had typical clinical, hematologic and blood group serologic findings of autoimmune hemolytic anemia except for one important exception; with most commercially available broad spectrum anti-human sera the direct antiglobulin tests were negative. With reagents prepared in the laboratory which were found to be relatively less potent in and anti-IgG and IgM activity but which utilize a short period of incubation after mixing with the washed cells, the tests were all clearly positive. If incubation were employed with the commercial reagents, the tests were positive. Further studies showed that the patient's cells were coated exclusively with IgA and that a commercial reagent, although potent in anti-IgG and anti-IgM, was relatively deficient in anti-IgA. It is proposed that incubation compensates for the latter and is cautioned that incubation, with reagents potent in anti-IgG, could lead to false negative reactions with weakly IgG sensitized cells due to antibody surplus prozones of inhibition. This case illustrates that the rare instances of "Coombs negative immune hemolytic anemias" may be based on mechanisms such as those reported here and, that to be ideal, a broad spectrum anti-human serum should have balanced anti-immunoglobulin activities in relation to its incubation time.

Anemia, Hemolytic, Autoimmune↗
PubMed1991

Performance of cryptococcus antigen latex agglutination kits on serum and cerebrospinal fluid specimens of AIDS patients before and after pronase treatment.

Cryptococcal antigen titers in 97 serum and 42 cerebrospinal fluid (CSF) specimens from 37 AIDS patients with culture-proven cryptococcal infection were determined with the Meridian kit (Meridian Diagnostics Inc., Cincinnati, Ohio) before and after treatment with pronase. The geometric mean titers before and after pronase treatment were 1:45 and 1:588 in serum and 1:97 and 1:79 in CSF, respectively. Only on serum (but not CSF) specimens after pronase treatment were (i) titers increased by 2 to 13 dilutions on 57% of the specimens, all of which had titers of less than or equal to 1:128 before pronase treatment, (ii) false-negative reactions on 27% of specimens before pronase treatment eliminated, all of which had titers from 1:4 to 1:4,096, (iii) prozone-like reactions (titer, less than or equal to 1:256) on 9% of the specimens before pronase treatment eliminated, and (iv) agglutination reactions on all specimens stronger and easier to interpret. Antifungal agents added to serum as well as freeze-thaw cycles did not change antigen titers in serum. After two separate tests, the same titers were obtained on 94% of 35 serum specimens that were treated with pronase and on 96% of 53 CSF specimens that were not treated with pronase. A total of 26 serum specimens and 28 CSF specimens from patients with no cryptococcal disease were negative before and after pronase treatment. The IBL kit (International Biological Labs Inc., Cranbury, N.J.) was compared with the Meridian kit on 41 serum specimens and 14 CSF specimens. Results from the two kits agreed on 54 and 68% of serum specimens and 86 and 93% of CSF specimens before and after pronase treatment, respectively. The IBL kit generally produced higher titers on specimens in disagreement and produced no prozone-like reactions. Routine pronase treatment of serum is recommended with the Meridian kit in order to eliminate false-negative and unclear agglutination reactions by producing a consistent interpretation of agglutination reactions. CSF specimens do not require pronase treatment. Titer results produced by the kits from the two different manufacturers varied considerably: the kits should not be used interchangeably for determining antigen titers in serum specimens.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Comparative evaluation of five agglutination techniques and a new miniaturized system for rapid identification of methicillin-resistant strains of Staphylococcus aureus.

The speciation of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant diagnostic problem when rapid identification methods such as slide agglutination tests, are used, because of the high proportion of false-negative reactions. 150 perfectly identified MRSA strains were tested on 5 commonly used agglutination reagents ("Bacto staph latex test", "Monostaph", "Pastorex staph", "Staphaurex", and "Staphyslide test") in comparison with a new micromethod ("RAPIDEC staph") which detects a type of staphylocoagulase within 2 hours by a fluorescence test. The "RAPIDEC staph" reagent enabled identification of all the MRSA while the agglutination tests gave poorer results: "Monostaph" correctly identified 64.6% of strains, "Staphyslide", 59.3%, "Bacto staph latex test", 44.6%, "Pastorex staph", 38.6% and "Staphaurex", 28.6%. These results show that agglutination slide tests are not reliable enough for the identification of MRSA which are more and more encountered in hospital wards. The authors recommend not to use slide agglutination methods. They suggest the tube test for coagulase which is the reference technique, although it is time-consuming and not well standardized. The results of this evaluation encourage the use of the "RAPIDEC staph" reagent since it is an easy-to-use, reliable technique for the rapid identification of Staphylococcus aureus.

Agglutination Tests↗
PubMed2006

A new MSPQC system for rapid detection of pathogens in clinical samples.

A new multi-channel series piezoelectric quartz crystal (MSPQC) system for detection of pathogens in clinical sample was proposed. Some factors, which affect the detection of pathogens by using MSPQC, were all investigated. A total of 650 clinical samples were detected by MSPQC and compared with licensed BACTEC 9120 system (Becton Dickinson Diagnostic Instrument Systems, Sparks, MD, USA) simultaneously in the Third Xiangya Hospital of Central South University, China. When the incubation period was 5 days, two systems had similar detected results: the MSPQC system detected 123 growth of 650 (18.92%) bottles while the BACTEC 9120 detected 125 growth of 650 (19.23%) bottles. The MSPQC had 2 false-positive signals and 2 false-negative signals. However, BACTEC 9120 had 3 false-positive signals and 0 false-negative signals. Further identifications of bacteria were run by VITEK-2 (bioMérieux China Ltd.), 5% sheep blood trypticase soy agar (SBA) and chocolate agar (CA). Comparing with BACTEC 9120, MSPQC system possesses following advantages: shorter average detection time, less blood volume needed, less false-positive results and low cost. It can also provide information in real time. So MSPQC has a wonderful perspective in clinical application.

Bacteremia↗