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Biomedical subjects

N M Burdash

Publications and source records attributed to N M Burdash.

At least 19 recordsLinked to original sources
PubMed1990

White cell subpopulations in autoimmune infertile men and their wives with cytotoxic sperm antibodies.

Sixty six infertile men with cytotoxic sperm antibodies had fewer and lower percentages of OKT4-positive helper/inducer T lymphocytes p = 0.004 and 0.003, respectively), than the fertile (n = 14) and infertile (n = 12) antibody-negative controls. Ratio of OKT4/OKT8 was decreased (p less than 0.01), while numbers of OKDR and BD-Leu12 positive predominantly B lymphocytes were increased (p less than 0.0001) in infertile men with sperm antibodies. T lymphocytes positive for OKT3, OKT11 and OKT4 and the OKT4/OKT8 ratio were decreased in infertile women with sperm antibodies, while B lymphocytes positive for OKDR and BD-Leu12 were increased in infertile women with or without sperm antibodies (p less than 0.0001, versus fertile controls). Lymphocyte responses to phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogen (PWM), however, were similar in 20 fertile and 136 infertile couples. Lymphocytes from infertile men with sperm antibodies had an enhanced stimulatory response to autologous sperm and seminal plasma. It is concluded that sperm antigens from autoimmune infertile men stimulate heightened immune responses to sperm antigens and altered distribution of white cell populations in both partners.

Adult↗
PubMed1987

Evaluation of the syphilis Bio-EnzaBead assay for detection of treponemal antibody.

An enzyme-linked immunosorbent assay for Treponema pallidum antibody (Syphilis Bio-EnzaBead Kit; Organon Teknika Corp., formerly Litton Bionetics, Kensington, Md.) was compared with the standard fluorescent treponemal antibody absorption test for syphilis (indirect fluorescent-antibody confirmatory test; Zeus Scientific Inc., Raritan, N.J.). Six hundred specimens tested in the rapid plasma Reagin card test (Hynson, Westcott and Dunning, Inc., Baltimore, Md.) and microhemagglutination assay for antibodies to T. pallidum (Ames Division, Miles Laboratories, Inc., Elkhart, Ind.) were used for comparison testing. One hundred and sixty-two specimens were from either persons with syphilis or persons whose history was unknown but who showed reactive serology, whereas 438 were from persons without syphilis. The reactivity of each serum by the Bio-EnzaBead test was determined visually and from optical density readings. Excellent reproducibility of visual readings was obtained; all results were within +/- 1 gradation of the expected readings in all 60 coded sera tested. Overall agreement between the Bio-EnzaBead and fluorescent treponemal antibody absorption test results was 96.3% when read visually and greater than or equal to 95.7% when using optical density readings. Our data indicate that Bio-EnzaBead results read at 405 nm and determined by using the mean antigen optical density reading of the nonreactive control plus 0.025 as the cutoff value provide an overall sensitivity and specificity of 93.0 and 98.6%, respectively, along with the best agreement with the fluorescent treponemal antibody absorption assay. Ease of performance and objectivity also contribute toward the acceptability of this assay as an alternative confirmatory test for syphilis.

Antibodies, Bacterial↗
PubMed1986

A comparison of three anti-double stranded DNA antibody assays on sera from SLE and other diseases.

Systemic lupus erythematosus (SLE) is a multisystem disorder accompanied by a diverse spectrum of serum autoantibodies. Antibodies to double stranded DNA (dsDNA) are considered to be the most specific marker for this disease. In this study the results obtained from three different assays for dsDNA are compared: an indirect fluorescence antibody assay (IFA), a radioimmunoassay (RIA) and, an enzyme-linked immunosorbent assay (ELISA), on 57 SLE sera and 28 Sera from other disorders. Correlation of these anti-DNA results are made with C3, C4, and antinuclear antibody (ANA) titers. Our results show the IFA assay is the most sensitive and the least specific of the three tests. The RIA was found to be the most specific and was approximately as sensitive as the ELISA. We also found significant inverse correlations between anti-dsDNA levels and circulating complement levels among SLE sera for all three assays. ANA titers were significantly correlated with all anti-dsDNA assays as well. However, these anti-dsDNA assays show only modest differences explainable by numerous mechanisms. Hence, a clearly superior anti-dsDNA method does not emerge from our study.

Antibodies, Antinuclear↗
PubMed1985

Enzyme-linked immunosorbent assay for detection of immunoglobulin G and M antibodies to teichoic acid in intravascular staphylococcal disease.

An enzyme-linked immunosorbent assay (ELISA) for detection of IgG and IgM antibodies to cell-wall teichoic acids of Staphylococcus aureus and three defined coagulase-negative staphylococci was tested using serum samples from 11 cases of intravascular coagulase-negative staphylococcal infections, 13 cases of Staphylococcus aureus endocarditis, and 24 patients with no evidence of infection. IgG antibody titers to all four teichoic acids in the 13 patients with Staphylococcus aureus endocarditis were significantly different from those in noninfected control patients (p less than 0.0001). In contrast, IgG antibody titers in serum from 11 cases of intravascular coagulase-negative staphylococcal infection were not significantly different from those in control sera. There were no differences in IgM antibody titers of the three groups. Although the ELISA was sensitive in detecting Staphylococcus aureus endocarditis, it was not reliable in the detection of intravascular coagulase-negative staphylococcal infections, even when tested with specific teichoic acid.

Animals↗
PubMed1985

Identification of gram-negative bacilli using the Autobac IDX.

The Autobac IDX is a new system for the rapid identification of clinically significant members of the Enterobacteriaceae and Aeromonas, Acinetobacter, Alcaligenes, Flavobacterium, Moraxella, and Pseudomonas species. The use of 18 differentially inhibitory compounds such as dyes and antibiotics along with a computerized algorithm based on a multivariate analysis provides the basis for the identification of 30 different groups of gram-negative bacilli. Required preliminary tests include observations on the presence or absence of swarming on a sheep blood agar plate and noting the following: growth, lactose fermentation, and bile precipitation from a MacConkey plate. Spot indole and spot oxidase tests must be performed as well. Identification by the Autobac IDX System takes 3-6 hr after completion of the preliminary tests. From a total of 403 isolates tested, the Autobac system agreed with the MicroID AND N/F systems on 382 identifications (94.8%). Four isolates, two Acinetobacter anitratus, one Serratia marcescens and one Moraxella osloensis could not be identified by IDX. Additional testing was required on 35 (8.7%) of the isolates.

Bacteria↗
PubMed1985

Lymphocyte phenotype changes in congenital and acquired perinatal cytomegalovirus infections.

The recognition that the multiple functions of T-lymphocytes are accomplished by separate subpopulations of cells that can be delineated both functionally and by antisera directed against specific cell surface markers is one major advance in immunology. Our study was directed at enumerating lymphocyte subsets in cytomegalovirus (CMV) perinatal infections with monoclonal antibodies and cell flow cytometry. Eight patients ranging in age from 1 week to 2 1/2 months were studied. Except for one term neonate, all of the infants were less than 36 weeks of gestational age, with a mean of 31.5 weeks (range 27-36 weeks) at birth. The mean birth weight of the premature infants was 1,211 gm (range 870-2420 gm). Five patients were 3 weeks old when studied and were classified as congenital CMV by viral isolation. Three were older than 2 months and were classified as acquired CMV. One of the acquired CMV infants was followed from birth to 6 months of age and had normal lymphocyte numbers at 2 weeks with alterations appearing at 8 weeks. The results of these studies indicated that in congenital CMV there is a normal to high helper/suppressor ratio. On the contrary, in acquired CMV this ratio is profoundly depressed because of significant increase in suppressor T-lymphocytes with borderline normal helper T-lymphocytes. In the latter group, the ratio increased with time after the acute infection episode. Our results agree with reported data indicating that in adults with CMV there is a depression of the helper/suppressor ratio during the acute stage with a return toward normal values during convalescence.

Antibodies, Monoclonal↗
PubMed1985

T-lymphocyte subset phenotypes: a multisite evaluation of normal subjects and patients with AIDS.

The present study was undertaken to determine normal ranges for blood lymphocytes labeled with the monoclonal antibodies OKT3, OKT11, OKT4, and OKT8 and for the OKT4/OKT8 ratio. In addition, 26 patients with AIDS, 51 AIDS suspects, and 44 patients with infections were studied. The results of these determinations from six different study sites indicate that there is excellent intersite agreement in normal values obtained. These normal ranges may be used in clinical laboratory reporting. Data from patients indicate that a simultaneous review and comparison of OKT4+ values, OKT8+ values, and depression of the OKT4+/OKT8+ ratio is a useful indicator in clinically diagnosed AIDS patients and in AIDS suspects. These changes, moreover, cannot be attributed only to infection present in these patients, since in infection, the OKT4+/OKT8+ ratio does not exhibit the severe depression seen in AIDS. These results should provide a useful reference for further studies in diseased subjects.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Evaluation of a rapid method to exclude the presence of certain enteric pathogens in stool specimens.

A new commercial method intended to exclude the presence of Salmonella spp., Shigella spp., and Yersinia enterocolitica and to presumptively identify Salmonella isolates within 2 h after primary isolation from stool specimens was evaluated. This system is marketed in Europe as API Z and in the United States as Rapid SST. The strip consists of five pairs of cupules for the screening of five lactose-negative colonies. The first cupule of each pair detects the presence of five enzymatic activities, whereas the second serves to maintain the strain for additional testing if necessary. A total of 197 fresh isolates from stool specimens and 217 stock cultures of Salmonella spp., Shigella spp., and Yersinia enterocolitica were tested, with the API 20E system as a reference method. In the stool specimens, 77.3% of the bacteria could be excluded from further workup for the presence of these organisms within 2 h. Over 97% of the stock strains and each of three fresh Salmonella isolates tested produced a reaction pattern corresponding to a correct presumptive identification. This reaction pattern was not produced by any isolate other than the Salmonella isolates. The API Z system can be used as a screen for the presence of Salmonella and Shigella spp. and can provide an accurate presumptive identification of Salmonella isolates within 2 h after primary isolation.

Bacteria↗
PubMed1984

Detection of platelet antibodies by flow cytometric analysis.

A rapid, sensitive indirect immunofluorescence assay utilizing flow cytometry to detect immune-mediated thrombocytopenia is described. Fluorescein-conjugated F(ab')2 antihuman IgG or IgGAM is reacted with donor platelets after their incubation with test sera and the resulting immune complex is measured using flow cytometric analysis. With this technique excess of Ig on the platelet, expressed as a ratio of fluorescence of test sera/autologous control sera, was noted in 24 of 30 patients (80%) with immune thrombocytopenias caused by auto- or allo-antiplatelet antibodies. Twenty-four sera from nonimmune thrombocytopenic patients were consistently negative. This technique has the advantage of being highly reproducible and avoids the subjective interpretation inherent with manual immunofluorescence assays.

Antibodies↗
PubMed1984

Are lymphocyte subset determinations affected by storage conditions?

The effect of overnight storage, either at room temperature or at 4 degrees C, on total T cells, helper cells, suppressor cells, and HLA-DR-positive cells was determined by flow cytometry and fluoresceinated monoclonal antibodies on peripheral whole blood samples. No differences were noted in any of the subsets regardless of storage conditions when samples were analyzed within 24 hr.

Adult↗
PubMed1983

Detection of anti-teichoic acid immunoglobulin G antibodies in experimental Staphylococcus epidermidis endocarditis.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of rabbit immunoglobulin G (IgG) antibodies to purified cell wall teichoic acids from the Staphylococcus aureus Lafferty strain and three strains of coagulase-negative staphylococci. Significant immunological cross-reactivity occurred only between the teichoic acid of S. aureus and one coagulase-negative preparation. The ELISA was used to determine the serum IgG response to Staphylococcus epidermidis in a rabbit model of aortic valve endocarditis. Blood samples were drawn before inoculation and then every 5 days until death or sacrifice at 32 to 35 days postinoculation. Valve vegetations were culture positive at autopsy in 16 (59%) of the 27 catheterized rabbits. Antibody titers in this culture-positive group and the culture-negative group began to rise as early as day 6. Although both groups demonstrated an antibody response, the culture-positive group attained a significantly higher titer on days 26 and 31. Antibodies also rose in a control group of rabbits without a heart catheter but which were inoculated with bacteria. Again, the antibody titer was significantly less than that for the culture-positive group. This ELISA may be useful for the diagnosis of coagulase-negative staphylococcal infections in humans.

Animals↗
PubMed1983

Acridine orange staining and radiometric detection of microorganisms in blood cultures.

To determine whether acridine orange (AO) staining of blood cultures could be used as a substitute for blind subculture when used in conjunction with the BACTEC system (Johnston Laboratories, Inc., Towson, Md.), the two methods were compared on all BACTEC-negative specimens. Since blind subcultures were routinely performed in our laboratory on days 2 and 6 of incubation, AO staining was also performed on these days. Cultures which were BACTEC positive on day 1 of incubation were not included in the study. Of the 2,395 bottles tested after 2 days of incubation, 106 were subculture positive. Of these, 96 (90.6%) were also AO positive and BACTEC positive, 3 (2.8%) were AO positive and BACTEC negative, and 7 (6.6%) were AO negative and BACTEC positive. Of the 3,487 bottles tested on day 6 of incubation, 14 were subculture positive; 7 (50%) of these were AO positive and BACTEC positive, and seven were AO positive and BACTEC negative. Of the total of 10 culture-positive bottles missed by BACTEC, all were positive, and all 10 companion aerobic bottles were BACTEC positive. In both phases of the experiment, there was a total of only four false-positive AO stains. As a result of this investigation, we have substituted AO staining for blind subculturing of BACTEC-negative bottles.

Acridine Orange↗
PubMed1983

Evaluation of a commercial counterimmunoelectrophoresis kit for detection of Staphylococcus aureus teichoic acid antibodies.

A commercial kit from Diagnostica, Inc., Miami Fla., was studied for its ability to detect antibodies to the teichoic acids of Staphylococcus aureus. A comparative study of the Diagnostica counterimmunoelectrophoresis (CIE) system and our gel double-diffusion method was undertaken with 156 serum samples from 142 patients. Included were 25 cases of staphylococcal and non-staphylococcal endocarditis, 30 cases of S. aureus bacteremia, 19 cases of nonbacteremic S. aureus infection, 39 cases of hospitalized patients without a staphylococcal infection, and 29 normal controls. Agreement between methodologies was attained in 138 (88.5%) of the 156 samples tested and in 127 (89.4%) of the 142 patients. Of 13 patients with culture-proven S. aureus endocarditis, significant antibody titers were found in all patients (100%) by CIE and in 12 patients (92.3%) by double diffusion. No significant titers were found in normal sera by CIE, but four sera were positive by double diffusion. Of 80 sera from patients with no evidence of S. aureus infection, 4 (5.0%) were positive by CIE and 7 (8.8%) were positive by double diffusion. The Diagnostica CIE kit appears to provide a suitable means for the detection of deep-seated S. aureus infections.

Antibodies, Bacterial↗
PubMed1983

Immunological diagnosis of systemic candidiasis by counterimmunoelectrophoresis and quantitative immunofluorescence using purified antigens.

The advantages of two different immunological approaches to the diagnosis of systemic candidiasis have been studied. Counterimmunoelectrophoresis (CIE) using purified cytoplasmic protein antigens and quantitative immunofluorescence (QIF) using purified polysaccharide antigens have proven to be approaches giving better discrimination between systemic and nonsystemic candidiasis. Using CIE and yeast cytoplasmic proteins we obtained nine positive reactions in 12 patients with systemic candidiasis, and none in 23 patients with other types of C albicans infection or in 30 normal healthy controls. Using quantitative immunofluorescence and mycelial polysaccharide antigen we obtained positive reactions in all tested sera from systemic candidiasis patients (14), but we also obtained positive reactions (although generally of lower magnitude) in 4 of 14 patients with localized or mucocutaneous candidiasis. It appears that although neither of the tests has 100% specificity and sensitivity, their use individually or in combination may result in valuable data to assist in establishing a diagnosis of systemic candidiasis.

Antibodies, Fungal↗
PubMed1982

Rapid detection of Haemophilus influenzae type b in cerebrospinal fluid by commercial coagglutination and latex agglutination kits.

The ability of two commercial kits to detect Haemophilus influenzae type b antigen in cerebrospinal fluid was evaluated. Results obtained by Bactogen, a latex agglutination test, and Phadebact, a coagglutination test, were compared to counterimmunoelectrophoresis, Gram stain and culture results. One hundred and seven specimens of cerebrospinal fluid were tested. Thirty were found to contain bacteria, 20 of which were Haemophilus influenzae type b. All 20 were positive by Bactogen and Phadebact testing, 19 were culture positive, 18 were positive by counterimmunoelectrophoresis and 15 had gram-negative bacilli seen on Gram stain. The culture negative specimen contained microscopically visible gram-negative bacilli and was from a patient on antimicrobial therapy who was previously Haemophilus influenzae type b culture positive. No false positives from other genera or the 77 culture negative specimens occurred with Phadebact, Bactogen or counterimmunoelectrophoresis.

Agglutination Tests↗
PubMed1982

Identification of Streptococcus pneumoniae by the Phadebact coagglutination test.

The Phadebact Pneumococcus Test is a coagglutination slide test for the serological identification of Streptococcus pneumoniae. Of 200 alpha-hemolytic streptococcal isolates, coagglutination test results agreed with those of optochin susceptibility and bile solubility in 189 cases, 105 of which were identified as S. pneumoniae by all three methods. The Phadebact test was 100% (113 of 113) sensitive and 98% (85 of 87) specific and was more sensitive than counterimmunoelectrophoresis in detecting the presence of pneumococcal antigen in cerebrospinal fluid. In fluids seeded with known amounts of pneumococcal antigen, it consistently detected lower levels than did counterimmunoelectrophoresis. The test provides a rapid and simple method for the definitive identification of S. pneumoniae.

Agglutination Tests↗