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Biomedical subjects

R W Ryan

Publications and source records attributed to R W Ryan.

At least 19 recordsLinked to original sources
PubMed1996

Evaluations of enzyme-linked immunosorbent assay procedure for determining specific Epstein-Barr virus serology and of rapid test kits for diagnosis for infectious mononucleosis.

Using the results of Epstein-Barr virus-specific immunofluorescence serology as the "gold standard," we found that the sensitivities of the five rapid test kits varied from 78 to 84% and specificities varied from 89 to 100%. Enzyme-linked immunosorbent assay-determined specific Epstein-Barr virus antibody profiles had a sensitivity and specificity of 98.6 and 95.5%, respectively.

Antibodies, Viral↗
PubMed1994

The risk of acquiring Lyme disease or babesiosis from a blood transfusion.

To determine the risk of acquiring Lyme disease or babesiosis from blood transfusion, serum was collected before and 6 weeks after patients received multiple transfusions during cardiothoracic surgery and antibodies to Borrelia burgdorferi and Babesia microti were measured. Of 155 subjects, 149 received 601 total units of packed red blood cells (PRBC) and 48 received 371 total units of platelets. No patient developed clinical or serologic evidence of Lyme disease; 1 (who received 5 units of PRBC) developed clinical and serologic evidence of babesiosis. The risk of acquiring Lyme disease from a transfused unit of PRBC was 0 (95% confidence interval [CI], 0-0.5%) and from a transfused unit of platelets was 0 (95% CI, 0-0.8%); the same risks for babesiosis were 0.17% (95% CI, 0.004%-0.9%) and 0 (95% CI, 0-0.8%), respectively. The risk of acquiring either Lyme disease or babesiosis from a blood transfusion in Connecticut is very low.

Aged↗
PubMed1994

Use of recombinant OspC from Borrelia burgdorferi for serodiagnosis of early Lyme disease.

Infection with Borrelia burgdorferi, the etiologic agent of Lyme disease, is associated with an early and dominant humoral response to the spirochete's 23-kDa outer surface protein C (OspC). We have cloned and expressed OspC as a fusion protein in Escherichia coli and have shown that patient serum samples react with it in an enzyme-linked immunosorbent assay (ELISA) (S. J. Padula, A. Sampieri, F. Dias, A. Szczepanski, and R. W. Ryan, Infect. Immun. 61:5097-5105, 1993). Now we have compared the detection of B. burgdorferi-specific immunoglobulin M antibodies in 74 individuals with culture-positive erythema migrans by a whole-cell ELISA, immunoblot, and the recombinant OspC (rOspC) ELISA. Seventy-six negative controls were also studied. With all of the tests, there was a statistically significant association between the duration of disease and the frequency of a positive result. With the rOspC ELISA, the predictive value of a positive test was 100% and the predictive value of a negative test was 74%. Similar results were obtained with the whole-cell ELISA and with the immunoblot using as the source of test antigen a strain of B. burgdorferi which expresses abundant levels of OspC. We conclude that the use of rOspC in an ELISA is a convenient, readily automated, and easily standardized test for the serodiagnosis of early Lyme disease.

Antibodies, Bacterial↗
PubMed1993

Molecular characterization and expression of p23 (OspC) from a North American strain of Borrelia burgdorferi.

We have found that sera from patients with early stages of Lyme disease contain predominant immunoglobulin M reactivity to a major 23-kDa protein (p23) from Borrelia burgdorferi 2591 isolated in Connecticut. To characterize this immunodominant antigen, we cloned and sequenced p23 and found it to be 83% identical by nucleotide sequence and 75% identical by amino acid sequenced to pC (recently renamed OspC), an abundantly expressed protein on the outer surface of PKo, a European strain of B. burgdorferi (B. Wilske, V. Preac-Mursic, S. Jauris, A. Hofmann, I. Pradel, E. Soutschek, E.Schwab, G. Will, and G. Wanner, Infect. Immun. 61:2182-2191, 1993). In addition, immunoelectron microscopy localized p23 to the outer membrane, confirming that p23 is the strain 2591 homolog of OspC. The North American strain B31, commonly used in serologic assays for Lyme disease, does not express OspC. Northern (RNA) blot analysis detected low levels of ospC mRNA in B31, and DNA sequencing of the ospC gene from B31 revealed a 54-bp deletion in the upstream regulatory region, possibly accounting for the low transcriptional activity of ospC. The ospC coding region from B31 was cloned and antibody-reactive OspC was expressed in Escherichia coli. An immunoglobulin M enzyme-linked immunosorbent assay using recombinant OspC as the target antigen shows promise for the serodiagnosis of early stages of Lyme disease.

Amino Acid Sequence↗
PubMed1992

Persistence of serum antibodies to Borrelia burgdorferi in patients treated for Lyme disease.

To determine if antibodies to Borrelia burgdorferi persist after antibiotic treatment, we recalled 32 patients with Lyme disease from a primary care practice a mean of 16 months after treatment and analyzed initial and follow-up serum samples by ELISA and immunoblot assays. Of the eight patients whose initial serum specimens were positive for IgM antibody by ELISA, three had positive titers of IgM antibody at follow-up; of the 23 patients whose initial serum specimens were positive for IgG antibody by ELISA, 19 had positive titers of IgG at follow-up. Of the five patients whose initial serum specimens were positive for IgM antibody by immunoblot, two had positive titers of IgM antibody at follow-up; of the 30 patients whose initial serum specimens were positive for IgG antibody by immunoblot, 29 had positive titers of IgG antibody at follow-up. The bands on the IgG immunoblot remained remarkably constant during the period from analysis of the initial specimen to that of the follow-up specimen. Nine of the 32 patients had persistent or recurrent symptoms, and ELISA and immunoblot were not helpful for identifying these nine patients.

Adult↗
PubMed1990

Azithromycin in the treatment of sexually transmitted disease.

One hundred and eighty-two patients were enrolled in a randomized third-party blinded study to assess the efficacy and safety of azithromycin in the treatment of sexually transmitted diseases. Three regimens of azithromycin, including a single oral dose, were compared with a standard treatment with doxycycline. The patients were followed for four weeks. Efficacy was evaluated in 168 patients (113 azithromycin, 55 doxycycline). Fourteen patients had negative cultures or did not come for all follow-up visits. Of the 168, 138 were infected with Chlamydia trachomatis, 43 with Neisseria gonorrhoeae, and 45 with Ureaplasma urealyticum. Ninety-six per cent of patients with chlamydial infections and 92% of those with gonorrhoea were cured with azithromycin. Two patients infected with N. gonorrhoeae, four with C. trachomatis and six with U. urealyticum had positive cultures on follow-up visits after receiving azithromycin. Of these 11 patients with positive cultures on follow-up visits, seven (five with U. urealyticum and two with C. trachomatis) violated the protocol by having intercourse with infected individuals during the study. Azithromycin was very well tolerated; one patient complained of mild abdominal pain shortly after receiving the drug, seven patients complained of mild nausea and two patients had mild diarrhoea.

Adolescent↗
PubMed1989

Comparative evaluation of three products for the detection of Borrelia burgdorferi antibody in human serum.

Eighty human serum specimens tested concomitantly by immunoblot and an enzyme-linked immunosorbent assay developed jointly at the University of Connecticut School of Medicine and the Connecticut Agricultural Experiment Station were used to evaluate three commercially available diagnostic products for Lyme borreliosis. The sources of the kits were Hillcrest Biologicals, Cypress, Calif.; Whittaker Bioproducts, Walkersville, Md.; and Cambridge Bioscience, Worcester, Mass. When compared with Western blot analysis, the sensitivities and specificities, respectively, for the diagnostic assays were as follows: Hillcrest Biologicals, 93 and 75%; Whittaker Bioproducts, 73 and 100%; Cambridge Bioscience, 89 and 100%; and University of Connecticut School of Medicine, 96 and 92%.

Antibodies, Bacterial↗
PubMed1988

DNA probe versus culture for detection of Mycoplasma pneumoniae in clinical specimens.

The laboratory diagnosis of Mycoplasma pneumoniae is often difficult because of lengthy and complicated cultural methods and serological tests that may be both insensitive and nonspecific. In this study, 82 patients suspected of Mycoplasma pneumonia were cultured for M. pneumoniae, and their respiratory secretions were tested by a DNA probe for M. pneumoniae. The probe test was 100% sensitive and 98% specific compared to culture. This DNA probe, then, is an effective alternative method for the detection of M. pneumoniae in respiratory specimens.

Bacteriological Techniques↗
PubMed1988

Multicenter comparative evaluation of two rapid microscopic methods and culture for detection of Chlamydia trachomatis in patient specimens.

Four hundred and seventy-three men and women at high risk for sexually transmitted disease were tested for the presence of Chlamydia trachomatis in the urethra or the endocervix. Four groups were involved in this multicenter study of two direct fluorescent-antibody microscopy tests, Kallestad Pathfinder and Syva Microtrak, compared with culture techniques. Results from the test sites indicated that there was no significant difference overall in the sensitivity and specificity of the two test kits. However, there was some interlaboratory variation seen in the sensitivity of the microscopy, but little difference in the specificity. Either kit could be an effective screening method for C. trachomatis in high-risk populations.

Cervix Uteri↗
PubMed1988

Comparative evaluation of three commercial tests for detection of heterophile antibody in patients with infectious mononucleosis.

Infectious mononucleosis (IM) is caused by the Epstein-Barr virus. Commonly used laboratory tests used for diagnosis of IM include a screening test based on the observation that horse erythrocytes are agglutinated by the Paul-Bunnell antibody found in the serum of patients with IM. This study evaluated two latex agglutination (LA) kits for IM, Monolatex (Wampole Laboratories) and Immunoscan-IM (American MicroScan) (formerly Monogen; Biokit, S.A.), and compared them with Monospot (Ortho Diagnostic Systems) results on 220 patient sera. Discrepancies in the three test results were resolved with complete Epstein-Barr virus antibody profiles. They indicated that any of the three kits tested can be successfully used as a screening test for IM. The advantage of the LA kits is that no differential absorption step is necessary. When discrepancies were resolved, sensitivity and specificity of both LA kits were greater than 93%.

Adolescent↗
PubMed1987

Clinical and ecological characteristics of Vibrio vulnificus in the northeastern United States.

Multiple seawater sites in the northeastern United States, particularly Long Island Sound, and shellfish from Long Island Sound were sampled from April to November for 3 successive yr, 1983-1985. Hospitals in coastal and metropolitan areas of Connecticut were surveyed for the same 3-yr period, Vibrio vulnificus can be found in these waters during the summer months. The appearance of these virulent bacteria in both seawater and shellfish are a function of the water temperature; no V. vulnificus could be isolated until the temperature was approximately 17 degrees C. Although the risk of infection is small, as shown by isolation of this organism from patients, certain high-risk groups exist. Consumption of raw shell fish during the summer months should be discouraged in people with liver disease or patients on immunosuppressive therapy.

Animals↗
PubMed1986

Rapid detection of Chlamydia trachomatis by an enzyme immunoassay method.

Chlamydia trachomatis has been shown to be a major cause of sexually transmitted diseases in the United States. An enzyme immunoassay (Abbot Laboratories) has been developed that detects chlamydial antigen directly in the urogenital specimens of patients. We have evaluated specimens from 1,074 patients belonging to one of three risk groups. Three swabs were collected from each patient--one each for Neisseria gonorrhoeae, chlamydia cell culture, and enzyme immunoassay. When compared with cell culture, the sensitivity and specificity of the enzyme immunoassay for symptomatic males and females attending a sexually transmitted disease clinic was 82% and 100%, and 91.3% and 95.0%, respectively. A moderate risk group, consisting of female patients seen at either urology or gynecology clinics for genitourinary symptoms was also evaluated. The sensitivity and specificity of the test on this group was 96% and 96.7%. A population of females at low risk were also screened for chlamydial infection. In this group, the sensitivity and specificity of the enzyme immunoassay was 89.3% and 93.2%, respectively. This rapid test is a highly specific and sensitive procedure for the detection of chlamydial antigen in genital specimens from high risk female patients as well as symptomatic males.

Antigens, Bacterial↗
PubMed1986

Considerations in the laboratory diagnosis of antibiotic-associated gastroenteritis.

Clostridium difficile has been shown to be the major cause of antibiotic-associated gastroenteritis in both humans and experimental animals. During the past few years an increasing number of laboratories have attempted to detect, isolate, and identify this organism and its toxin from clinical samples. Direct visualization of C. difficile in patient specimens using immunofluorescent microscopy has been proposed. The major disadvantage of this method was its lack of specificity due to crossreaction with other clostridial species. Attempts to absorb the antisera with crossreacting strains also failed. Laboratory diagnosis of C. difficile in clinical specimens has relied on either culture using one or more selective media or on the detection of specific cytotoxin in stool filtrates. Until recently the cytotoxicity assay was the only procedure available for the routine detection of cytotoxin and, as a result, has limited this test to laboratories with access to tissue culture facilities. As a result, there has been much interest in the development of immunochemical methods for the detection of C. difficile toxins. We originally reported on the detection of C. difficile toxin in stool filtrates using counterimmunoelectrophoresis. We examined 140 fecal specimens submitted for C. difficile toxin assay by counterimmunoelectrophoresis, using both unabsorbed and absorbed antitoxin, tissue culture, and bacterial culture. Using tissue culture assay as the reference method, the sensitivity of counterimmunoelectrophoresis and counterimmunoelectrophoresis-absorbed was 100% and the specificity 63.0% and 77.5%, respectively. Enzyme immunosorbent assays for the detection of toxin A from C. difficile have also been reported, however, at the present time they do not appear to be as sensitive as the cytotoxicity assay for toxin B (cytotoxin).(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1984

Comparative evaluation of three commercial products and counterimmunoelectrophoresis for the detection of antigens in cerebrospinal fluid.

Three commercial products and counterimmunoelectrophoresis were evaluated for their ability to detect microbial antigens of Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae in cerebrospinal fluid from 157 patients suspected of having meningitis. Thirty-four patients were diagnosed as having bacterial meningitis by culture, microscopy, or antigen detection. The overall results showed the following detection percentages; counterimmunoelectrophoresis, 76%; Phadebact CSF, 76%; Directigen, 82%, and Bactigen, 93%. The results with purified antigen revealed that latex agglutination was more sensitive than coagglutination, which in turn was more sensitive than counterimmunoelectrophoresis.

Agglutination Tests↗
PubMed1984

Role of Chlamydia trachomatis in acute pharyngitis in young adults.

It has recently been suggested that Chlamydia trachomatis may be a common cause of acute pharyngitis in adults. In a prospective investigation of 95 college students with acute pharyngitis, C. trachomatis was not isolated from any pharyngeal cultures. Further investigations are needed to better define the role of C. trachomatis in upper respiratory tract infections.

Acute Disease↗
PubMed1983

Improved immunologic detection of Clostridium difficile antigen by counterimmunoelectrophoresis.

An improved counterimmunoelectrophoresis (CIE) procedure for detection of Clostridium difficile antigen is described. Commercially available antiserum to C. difficile toxin was absorbed with whole cells of C. difficile. CIE (absorbed) was 100% sensitive and 77.5% specific when compared to the tissue culture toxin assay. Instances are noted in which the CIE (absorbed) and/or bacterial culture was positive and the tissue culture assay was negative.

Antigens, Bacterial↗