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S A Larsen

Publications and source records attributed to S A Larsen.

At least 37 records · Page 2Linked to original sources
PubMed1990

Sensitivity of treponemal tests for detecting prior treated syphilis during human immunodeficiency virus infection.

To evaluate the sensitivity of treponemal tests as a marker of prior syphilis in individuals with human immunodeficiency virus (HIV) infection, the syphilis serology of 109 homosexual men with a documented history of treated syphilis was compared with records of prior results and confirmed on stored serum samples. None of the HIV-seronegative individuals lost reactivity to a treponemal test, whereas 7% of the seropositive asymptomatic individuals and 38% of those with symptomatic HIV infection had loss of reactivity. Symptomatic HIV infection was associated with loss of reactivity, as a T4 lymphocyte count less than 200 X 10(6)/1, a T4-to-T8 ratio less than 0.6, a single prior episode of syphilis, and a low VDRL titer at the time of the last documented episode of syphilis. Although no conclusions can be drawn about the sensitivity of treponemal tests in patients with active syphilis and HIV infection, these data suggest that treponemal tests may not identify those previously infected with Treponema pallidum.

Adult↗
PubMed1989

Race and the prevalence of syphilis seroreactivity in the United States population: a national sero-epidemiologic study.

We used the 1978 National Health and Nutrition Examination Survey to examine the prevalence of positive syphilis serologies in the US population. Analysis of risk markers--gender, age, marital status, education, income, and residence--indicates that all except gender are associated with syphilis seroreactivity, independent of race. Controlling for associated risk markers, the Black-White odds ratio of syphilis seroreactivity is 4.7 (95% CI = 2.7, 8.2). Current knowledge of racial differences in sexual and health care behavior does not explain the Black-White difference in the prevalence of syphilis seroreactivity.

Adolescent↗
PubMed1989

Syphilis.

The clinical manifestations of syphilis can resemble many diseases. The diagnosis can be confirmed through serologic tests and by direct microscopic observation of Treponema pallidum, subspecies pallidum in lesion, biopsy, or autopsy specimens. Direct microscopic examination may be carried out by darkfield methods or by immunofluorescent staining. The serologic testing sequence is usually a screening nontreponemal test followed by confirmation with a specific treponemal test. Serologic tests for syphilis have been highly standardized in the past, but today quality control lies in the hands of the laboratorian.

Humans↗
PubMed1986

Detection of immunoglobulin M in cerebrospinal fluid from syphilis patients by enzyme-linked immunosorbent assay.

Cerebrospinal fluid (CSF) samples were evaluated in an immunoglobulin M enzyme-linked immunosorbent assay (IgM ELISA) for syphilis with sonic extracts of Treponema pallidum coated on polystyrene plates. The ELISA procedure was reproducible, and T. pallidum antigens were stable., A total of 15 CSF samples from patients with neurosyphilis, 18 CSF samples from patients with syphilis, 12 CSF samples from patients treated for syphilis, and 494 CSF samples from patients with neurologic or other systemic diseases were tested. The IgM ELISA gave reactive results in all of six symptomatic and congenital neurosyphilitic patients and none of nine asymptomatic neurosyphilitic patients. Of 524 CSF samples from nonneurosyphilitic individuals, 513 were nonreactive, resulting in 98% test specificity. The IgM ELISA in CSF should prove to be useful for confirmation of symptomatic neurosyphilis.

Albumins↗
PubMed1985

Serological response to syphilis treatment. A new analysis of old data.

One important aspect of the posttreatment evaluation of patients with early syphilis is assessment of serological test results. Using information previously collected from 818 patients in the Early Syphilis Study, we evaluated the seroresponse of people treated for primary or secondary syphilis. We generated curves describing the VDRL titer declines with time. The VDRL titer declined approximately fourfold at three months and eightfold at six months. These observations will allow clinicians to identify treatment failures or reinfections at the earliest possible time during their follow-up.

Antibodies, Bacterial↗
PubMed1985

Adenovirus ELISA for the evaluation of cerebrospinal fluid in patients with suspected neurosyphilis.

An enzyme-linked immunosorbent assay (ELISA) detecting antibodies against the adenovirus group antigen was used to examine cerebrospinal fluid (CSF) of suspected neurosyphilis patients for serum contamination or blood-brain barrier (BBB) leakage. Adenovirus antibodies are ubiquitous, produce high antibody titers, and rarely cause central nervous system (CNS) infections. Of 52 normal adult sera tested with this ELISA, only one lacked antibodies. CSF from 48 healthy individuals did not present a detectable amount of anti-adenovirus antibodies. CSF from 33 suspected neurosyphilis patients with positive results in the fluorescent treponemal antibody-absorption (FTA-ABS)-CSF test were examined. Eighteen showed anti-adenovirus antibodies indicating contamination of the CSF with peripheral blood or damaged BBB by syphilis or other disease, resulting in questionable CSF treponemal results. The remaining 15 of these patients appeared to be producing their anti-treponemal antibodies in the CNS. This procedure may prove to be of considerable help in excluding false positive FTA-ABS results in CSF samples.

Adenoviridae↗
PubMed1985

Four-step enzyme-linked immunosorbent assay for detection of Treponema pallidum antibody.

Further studies of a four-step enzyme-linked immunosorbent assay procedure to detect Treponema pallidum antibody are described. High-titered antibody, produced in rabbits by intravenous injection of T. pallidum, was used to coat polyvinyl chloride microtiter plates. To these plates a known concentration of T. pallidum was added, followed in successive steps by serial dilutions of human sera and appropriately diluted peroxidase-labeled anti-human immunoglobulin G antibody. O-Phenylenediamine was the substrate. A total of 340 sera were obtained from the DeKalb County Sexually Transmitted Diseases Clinic, Atlanta, Ga., and examined within 3 days of receipt. Ninety-six percent test agreement between the enzyme-linked immunosorbent assay and the fluorescent treponemal antibody absorption-double staining test was obtained. A total of 372 additional sera stored at -20 degrees C were examined. The overall sensitivity of the enzyme-linked immunosorbent assay with sera from patients with various stages of syphilis was 96%. With sera from uninfected individuals, the specificity of the enzyme-linked immunosorbent assay was 95%. No antigen instability was noted with the two antigen preparations used during this evaluation.

Antibodies, Bacterial↗
PubMed1985

Rheumatoid factor in syphilis.

Immunoglobulin M (IgM) antibodies directed against IgG antibodies (rheumatoid factor [RF]) are known to occur often in patients with syphilis and to interfere with serological tests measuring specific antibodies of the IgM class. In this study we examined the occurrence and specificity of the RF and demonstrated a simple method to detect and eliminate the RF for a specific Treponema pallidum IgM enzyme-linked immunosorbent assay. We measured the occurrence of the RF with a sensitive enzyme-linked immunosorbent assay and found that it increased with the duration of syphilitic disease: 1 of 13 primary syphilis serum specimens, 3 of 13 secondary syphilis serum specimens, and 10 of 27 latent syphilis serum specimens were reactive in this RF test. Those sera containing IgM RF were immunoprecipitated with anti-human gamma chain antibodies and 2% polyethylene glycol until the RF was removed. One serum specimen from a patient in the secondary stage of syphilis and eight serum specimens from patients with latent disease still presented the RF after immunoprecipitation. Removal of the IgG antibodies also improved the sensitivity of the treponemal IgM test, indicating competition of these antibodies for binding sites of the antigen. The enzyme-linked immunosorbent assays for detection of RF and antitreponemal IgM antibodies are performed on the same plate. Theoretically, only sera positive for both tests have to be immunoprecipitated. But our findings indicated an increase in sensitivity of the IgM enzyme-linked immunosorbent assay after removal of IgG antibodies responsible for competition at the binding sites.

Antibodies, Anti-Idiotypic↗
PubMed1985

Epidemiological characterization of Neisseria gonorrhoeae by lectins.

A total of 101 isolates of penicillinase-producing and non-penicillinase-producing Neisseria gonorrhoeae with known nutritional requirements, plasmid content, and serovars, were examined for lectin agglutination patterns. These isolates were from outbreaks in Georgia, California, Hawaii, and Pennsylvania. Cell suspensions made from 16- to 18-h cultures were mixed with 14 different lectins, and the resultant agglutination patterns were classified as agglutination groups. Among the 101 isolates tested, 24 different agglutination groups were demonstrated. Of the organisms tested, 55% were located in 3 of the 24 groups, and 86% of the isolates reacted with the lectins Trichosanthes kinlowii, Griffonia simplicifolia I, peanut agglutinin, soybean agglutinin, potato agglutinin, and wheat germ agglutinin. One isolate did not react with peanut or potato agglutinin, five isolates lacked reactivity with potato agglutinin, and six isolates did not react with wheat germ agglutinin. Of the wheat germ-negative isolates, four were from Pennsylvania and were identical with regard to auxotype, plasmid content, serovar, and lectin group. The other two wheat germ-negative isolates were from California and were unrelated by the same criteria to the four Pennsylvania isolates and to each other. Among the isolates tested, there were no differences in lectin groups with regard to the sex of the patient. In the Georgia collection, agglutination with one lectin group was confined to isolates of serogroup IA. This association was not observed for the other geographic areas. Some isolates showing identical auxotype, plasmid content, and serovars could be differentiated based on lectin agglutination patterns, whereas other isolates were identical by all testing criteria.

Agglutination Tests↗
PubMed1985

Lectin characterization of gonococci from an outbreak caused by penicillin-resistant Neisseria gonorrhoeae.

A total of 40 Neisseria gonorrhoeae isolates, representing 19 penicillin-resistant isolates (from 8 heterosexual patients and 11 homosexual patients) and 21 penicillin-susceptible isolates (from 15 heterosexual patients and 6 homosexual patients) and obtained from the same geographic area, were examined. Lectin agglutination patterns were based on the reactivity of the isolates with the following 14 lectins: concanavalin A, Lens culinaris, Trichosanthes kinlowii, Griffonia simplicifolia I, Arachis hypogeae (peanut agglutinin), Glycine max (soybean agglutinin), Dolichos bifloris, Griffonia simplicifolia II, Solanum tuberosum (potato starch agglutinin), Triticum vulgaris (wheat germ agglutinin), Limax flavus, Phaseolus vulgaris, Ulex europaeus I, and Lotus tetragonolobus. All isolates were serotyped with monoclonal antibodies specific for gonococcal outer membrane protein I and auxotyped, and the plasmid content was determined. Resistant patient isolates were selected for their decreased penicillin susceptibility, and control isolates were selected for their penicillin susceptibility. Even though the patient isolates demonstrated resistance to penicillin, no phenotypic differences in lectin-grouping patterns were demonstrated between the two study groups; i.e., two predominant lectin groups were observed. No resistance-associated plasmids were detected. All patient isolates were serogroup IB (serovars IB-1, IB-2, and IB-4), whereas 12 of 21 control isolates were serogroup IA (P less than 0.05). Isolates obtained from different anatomical sites in the same patient (cervical and rectal) agreed with regard to lectin patterns and serovars but not auxotypes.

Agglutination Tests↗
PubMed1984

Interlaboratory comparison of the toluidine red unheated serum test antigen preparation.

The toluidine red unheated serum test (TRUST) antigen, a macroscopic flocculation test antigen developed by Pettit et al. (J. Clin. Microbiol. 18:1141-1145, 1983) by modifying the color-coded antigen of Kasatiya and Lambert (Appl. Microbiol. 28:317-318, 1974), was compared with the Venereal Disease Research Laboratory (VDRL) slide and rapid plasma reagin (RPR) 18-mm circle card tests for sensitivity, specificity, and reproducibility. Two lots of TRUST antigen were prepared by two laboratories in the Centers for Disease Control. Both laboratories performed the TRUST and VDRL slide test on serum samples from 1,102 patients attending the DeKalb County, Georgia, Sexually Transmitted Disease Clinic. In addition, one laboratory performed the RPR card test. Reactive sera were quantitated in the three nontreponemal tests and confirmed with the fluorescent treponemal antibody absorption test. The sensitivity in untreated syphilis for all nontreponemal tests involved was 98.4%. The specificity for these tests was 98.6%. The qualitative reproducibility among the four lots of TRUST antigen, VDRL slide, and RPR card tests was 98.2%. Only 20 sera showed discrepant results. Intralaboratory reproducibility of the two TRUST antigens was 100% for one laboratory and 99.6% for the other. Interlaboratory reproducibility for the four lots of TRUST and the VDRL slide test was 99%. Quantitative agreement +/- 1 dilution between the TRUST and RPR card test was 92.3%, and quantitative agreement +/- 1 dilution for the TRUST and RPR card test versus the VDRL slide test averaged 50%. The TRUST appeared to be comparable to the RPR card test in all parameters compared.

Antigens, Bacterial↗
PubMed1984

Double-conjugate enzyme-linked immunosorbent assay for immunoglobulins G and M against Treponema pallidum.

An enzyme-linked immunosorbent assay (ELISA) for the simultaneous measurement of immunoglobulin G (IgG) and IgM was developed to detect antibodies to Treponema pallidum. Wells of polystyrene microtiter plates were coated with T. pallidum antigen, diluted patient serum was added, and IgG and IgM which bound to the T. pallidum antigen were measured by the simultaneous addition of alkaline phosphatase-labeled anti-human IgG and horseradish peroxidase-labeled anti-human IgM. Bound IgG was detected first, followed by bound IgM. After development of the procedure, 145 categorized sera were evaluated: 60 from individuals without syphilis; 62 from patients with syphilis, including 22 with primary, 20 with secondary, and 20 with latent phases of syphilis; and 23 from patients with rheumatoid arthritis. Of the 60 sera from individuals without syphilis, 100% were nonreactive for IgG antibody and 16% were reactive for IgM. Of the 23 sera from patients with rheumatoid arthritis, 3 were reactive for IgG and 3 were nonreactive for IgM. Of the 62 sera from patients with syphilis, 61 (98%) were reactive for IgG antibody with increased titers as the stage of syphilis increased, whereas IgM reactivity decreased. This enzyme-linked immunosorbent assay appears to be a simple method for the simultaneous measurement of antibodies under equal assay conditions.

Antibodies, Bacterial↗
PubMed1984

A case-control study of stillbirths at a teaching hospital in Zambia, 1979-80: serological investigations for selected infectious agents.

Sera were obtained from 266 mothers of singleton stillborn babies (cases) and 266 mothers of live-born babies (controls), matched for parity, who delivered at the University Teaching Hospital, Lusaka, Zambia, between October 1979 and April 1980. Tests were performed on 262 samples from cases and 261 from controls. The microhaemagglutination assay for Treponema pallidum (MHA-TP) was reactive in 54% of cases and 29% of controls; the rapid plasma reagin (RPR) 18-mm circle card test was reactive at a dilution of 1:16 or greater in 29% of cases and in 3.5% of controls. Both these differences are highly significant.Sera from cases and controls were further examined for evidence of cytomegalovirus, human (alpha) herpesvirus, hepatitis B virus, toxoplasma, and plasmodium infections. The only difference between sera from cases and controls was that cytomegalovirus antibody titres >/= 1:1024 occurred more often among cases. There was no relationship between antibody titre and birth weight.The results of this study emphasize the importance of screening pregnant women for syphilis. Treatment of those found to be infected should help prevent stillbirths due to syphilis.

Antibodies↗
PubMed1983

The relative efficacy of imaginal and in vivo desensitization in the treatment of agoraphobia.

Claims have often been made that in vivo procedures are generally superior to imaginal approaches in the clinical management of anxiety and avoidance behavior. Such claims seem unwarranted in that the relevant clinical research appears only to have involved either flooding or rapid exposure techniques. The aim of the present study was specifically to examine the relative efficacy of imaginal and in vivo desensitization in the clinical management of debilitating phobia. Six agoraphobic women participated in the study which employed a multiple-baseline single-subject methodology. Severity of phobia was repeatedly assessed on measures of avoidance behavior and subjective distress, and subjects self-monitored pulse rate. Significant reductions in phobic behavior were observed during both imaginal and in vivo desensitization, but neither treatment was found to be more effective than the other. Moreover, the same pattern of results was observed for both treatment and generalization settings. As such, the results do not support previous suggestions that in vivo exposure is necessarily superior to imaginal desensitization in the treatment of agoraphobia. Encouraging follow-up results provided some confirmation of previous findings indicating the effectiveness of self-management procedures in the long-term control of agoraphobia.

Adult↗
PubMed1983

Fluorescent treponemal antibody absorption double-staining test evaluation.

The fluorescent treponemal antibody absorption (FTA-ABS) double-staining (DS) test has been developed for microscopes equipped with incident illumination, and the procedure offers many advantages over the FTA-ABS test when tests are performed with this equipment. In this study, 346 fresh sera, including 35 from patients with syphilis, were evaluated by the FTA-ABS DS test. Parameters for investigation included two readers, each using a different microscope; a new FTA-ABS DS test reporting system; sera heated at 56 degrees C for 30 min versus unheated sera; and sera retested after at least 2 weeks of freezer storage. Agreement for FTA-ABS DS test readings between the two microscopes was 99%. Between-test agreement for the FTA-ABS test with the conventional reporting system and the FTA-ABS DS test with the new reporting system was 95%. Sensitivity calculations based on reactivity for the 35 syphilis sera were 94% for the FTA-ABS DS test and 91% for the FTA-ABS test. Specificity calculations based on non-reactivity of nonsyphilis sera were 98% for the FTA-ABS DS test and 93% for the FTA-ABS test. Differences in percentages appeared to be related to borderline readings in the FTA-ABS test. For example, if the same reporting system was used for the reference FTA-ABS test, the specificity was 97%. When sera were examined within 48 h, no difference was observed in results obtained with heated and unheated sera. Sera frozen for 2 weeks showed comparable results in the FTA-ABS DS test and the FTA-ABS test. These findings strongly support the recommendation that the FTA-ABS DS test be accepted as a confirmatory test for syphilis. The new reporting system for the FTA-ABS DS test would be advantageous for the reference FTA-ABS procedure.

Evaluation Studies as Topic↗