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Biomedical subjects

S A Larsen

Publications and source records attributed to S A Larsen.

At least 55 records · Page 3Linked to original sources
PubMed1983

Comparison of a new rapid plasma reagin card test with the standard rapid plasma reagin 18-mm circle card test and the venereal disease research laboratory slide test for serodiagnosis of syphilis.

The rapid plasma reagin (RPR) card test manufactured by Beckman Instruments, Inc., was compared, qualitatively and quantitatively, with the Venereal Disease Research Laboratory (VDRL) slide test and the standard RPR 18-mm circle card tests for the serodiagnosis of syphilis. Sera from 638 individuals were used in this study. Two pilot lots and two production lots of antigen were submitted by Beckman Instruments, Inc., for evaluation. Qualitative agreement among the three RPR card tests was 98.1%; between the Beckman RPR card and the VDRL slide tests, 95.0%; and between the reference RPR card and the VDRL slide tests, 95.5%. The Beckman RPR card test was 95.3% specific, whereas the specificities of the reference RPR card and the VDRL slide tests were 98.8% and 96.1%, respectively. Sensitivities of the three nontreponemal tests were: Beckman RPR card test production lots, 94.7%; reference RPR card test, 96.8%; and VDRL slide test, 90.6%. Quantitative agreement +/- 1 dilution among the three RPR card tests was 93.0%, whereas quantitative agreement was approximately 40% when both RPR card tests were compared with the VDRL slide test. We found the Beckman RPR card test comparable to the standard RPR card tests. Therefore, the decision of which test to use for the serodiagnosis of syphilis is at the discretion of the user.

Antibodies↗
PubMed1983

EDTA-treated plasma in the rapid plasma reagin card test and the toluidine red unheated serum test for serodiagnosis of syphilis.

Both the rapid plasma reagin (RPR) 18-mm circle card test and the toluidine red unheated serum test (TRUST) were designed to be more rapid than the Venereal Disease Research Laboratory slide test for the serodiagnosis of syphilis. The RPR card test, although originally designed as the teardrop card test for use with plasma, has received recognition from the Centers for Disease Control as a standard test for syphilis for use with serum samples only. In this study, 132 EDTA plasma-serum pairs were tested in both the RPR card test and TRUST immediately after the blood was drawn and the serum or plasma was separated from the cellular constituents of the blood. The plasma samples were further tested at 24-h intervals of storage at 25 and 4 degrees C for 72 h. Special attention was paid to any increase in roughness in nonreactive specimens. The greatest increase in roughness (16.7%) was seen with the TRUST after 72 h at 25 degrees C. An additional 174 plasma-serum pairs were tested after 18 h of storage at 25 degrees C. Comparisons of the results of the 306 serum specimens with their corresponding plasma pairs gave 99.0% qualitative agreement for both tests. Quantitative agreement +/- 1 dilution between serum-plasma pairs tested within 18 h was 92.1% (35 of 38) for the RPR card test and 94.1% (32 of 34) for the TRUST. Our results with plasma from blood drawn with EDTA as the anticoagulant were comparable with results with serum specimens for both tests when plasma specimens were tested within 18 to 24 h.

Antibodies↗
PubMed1983

Toluidine red unheated serum test, a nontreponemal test for syphilis.

We have shown that a modification of the color-coded antigen developed by Kasatiya and Lambert (Appl. Microbiol. 28:317-318, 1974) can be used as a substitute for other nontreponemal antigens used in screening tests for syphilis. The antigen is based on the Venereal Disease Research Laboratory antigen, with EDTA, choline chloride, and toluidine red toner added. Performance of the toluidine red unheated serum test (TRUST) is identical to that of the rapid plasma reagin 18-mm circle card test (U.S. Department of Health, Education, and Welfare, Public Health Service Publication no. 411). In a series of preliminary evaluations, the TRUST antigen was found to be stable over a period of 6 months at 4 degrees C. In a comparison of TRUST with the rapid plasma reagin card test, the qualitative agreement was 100%, whereas agreement between these two tests and the Venereal Disease Research Laboratory slide test was 99.7%. The quantitative agreement +/- 1 twofold dilution between TRUST and the rapid plasma reagin card test was 100%; between TRUST and the Venereal Disease Research Laboratory slide test it was 75.0%; and between the rapid plasma reagin card and Venereal Disease Research Laboratory slide tests it was 60.0%.

Edetic Acid↗
PubMed1983

National case-control study of Kaposi's sarcoma and Pneumocystis carinii pneumonia in homosexual men: Part 2. Laboratory results.

The Centers for Disease Control conducted a case-control study to investigate an outbreak of Kaposi's sarcoma and Pneumocystis carinii pneumonia in homosexual men. The occurrence of these diseases was found to be associated with certain aspects of lifestyle, including a greater number of male sex partners per year, exposure to feces during sex, history of syphilis and non-B hepatitis, treatment for enteric parasites, and use of various illicit substances. Laboratory studies reflected both this lifestyle and the probable underlying cause of the Kaposi's sarcoma and P. carinii pneumonia--cellular immune deficiency. Patients were found to have lymphopenia, specifically a deficiency of the T-helper subpopulation, resulting in a reversal of the T-helper to T-suppressor ratio. Levels of IgG and IgA were increased. When compared with controls, patients were also found to have significantly higher titers of antibody to Epstein-Barr virus and cytomegalovirus, a higher prevalence of antibody to hepatitis A virus and Treponema pallidum, a lower prevalence of antibody to varicella zoster virus, and a higher frequency of isolation of cytomegalovirus.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Providing information more efficiently in pediatric practice.

Information delivery in a pediatric practice must be efficient in order to provide the vast amount of health care information available. The individual practitioner often has difficulty finding enough time to provide the information, in an optimal fashion, on a one-to-one basis. Three techniques are recommended to more efficiently transmit information: taping recorded messages on pediatric health topics; referring parents to sources of information specific to their children's ages; and establishing classes or group meetings. These educational approaches can greatly facilitate the delivery of health care to children.

Child↗
PubMed1982

Unheated serum reagin test as a quantitative test for syphilis.

The unheated serum reagin (USR) test, a standard qualitative test for syphilis, was evaluated for use as a quantitative test for the serodiagnosis of syphilis and as a means of determining the effectiveness of treatment. Tests were performed on 664 syphilitic sera from treated and untreated patients in the primary, secondary, and latent stages of the disease. Also included were 95 false-positive sera and 36 sera from presumably normal donors. The Venereal Disease Research Laboratory slide and rapid plasma reagin 18-mm circle card tests were used as a basis for comparison with the USR test. Results of the USR quantitative test paralleled the Venereal Disease Research Laboratory and rapid plasma reagin card quantitative tests with approximately 84% agreement. The advantages of the USR test make the findings of this study significant in that: (i) less technical manipulation is required to perform the USR test than the Venereal Disease Research Laboratory slide test; (ii) no labor cost is incurred for daily Venereal Disease Research Laboratory antigen preparation; and (iii) the USR antigen is less expensive than the rapid plasma reagin card tests antigen.

Antibodies↗
PubMed1982

Heated versus unheated sera in the hemagglutination treponemal test for syphilis.

Sera (920) were tested to evaluate the use of heated versus unheated sera in the hemagglutination treponemal test for syphilis. The heated and unheated samples were tested on the same day with the hemagglutination treponemal test for syphilis kit according to the manufacturer's protocol. Agreement of results between the heated and unheated sera was 99.2%. The reading pattern of agglutination was clearer and more distinct with heated sera; therefore, based solely on our preference for the reading patterns, we suggest that heated sera be used in the hemagglutination treponemal test for syphilis.

Hemagglutination Tests↗
PubMed1982

Evaluation of a new rapid plasma reagin card test as a screening test for syphilis.

This study evaluates the American Dade (Biokit Laboratories) rapid plasma reagin (Dade RPR) card test, currently used in Spain for the diagnosis of syphilis, which has been recently released to the U.S. market. Used as a basis for comparison with the Dade card test were the 18-mm standard rapid plasma reagin (standard RPR) card test and the Venereal Disease Research Laboratory (VDRL) slide test, using both fresh sera obtained from 505 individuals and paired serum-plasma specimens from 174 individuals. Results obtained proved the Dade RPR card test with serum to be very similar to the standard RPR card test; sensitivity was 92.3% and specificity was approximately 99% for both RPR card tests. Although the sensitivity of the VDRL slide test was lower at 88.5%, its specificity was also approximately 99%. Quantitatively, the agreement +/- 1 dilution between the two card tests was 93.6%. Agreement +/- 1 dilution between the Dade RPR card test and the VDRL slide test was 46.5% for sera, comparable to the standard RPR-VDRL agreement of 50%. In the limited evaluation of the RPR card tests with plasma, the specificity was 99.4% and the sensitivity was 100% for both tests. Quantitative agreement +/- 1 dilution between plasma and serum pairs was 100% for the Dade RPR card test. Our results showed that the Dade RPR card test is as sensitive and as specific as the standard RPR card test. Therefore, it was concluded that one card test has no particular advantage over the other.

Antibodies, Bacterial↗
PubMed1981

Fluorescent treponemal antibody-absorption double-staining procedure.

The fluorescent treponemal antibody-absorption double-staining step-by-step procedure and proposed reference reagents for the test are described. The test and reagents were evaluated in two separate laboratories on 265 fresh sera, and test results were compared with the reference fluorescent treponemal antibody-absorption test results performed in a third laboratory. The data indicate that the tests are comparable in the areas where the test is recommended for use. Problems with inadequate light filtration occurred, but these could be resolved. This test is recommended for use with microscopes equipped with incident illumination.

Antibodies, Anti-Idiotypic↗
PubMed1981

Specificity, sensitivity, and reproducibility among the fluorescent treponemal antibody-absorption test, the microhemagglutination assay for Treponema pallidum antibodies, and the hemagglutination treponemal test for syphilis.

Using 920 sera, we compared the specificity and reproducibility of the hemagglutination treponemal test for syphilis with those of the fluorescent treponemal antibody-absorption test and the microhemagglutination assay for Treponema pallidum antibodies; we found all three tests to be comparable. However, the hemagglutination treponemal test for syphilis, like the microhemagglutination assay for T. pallidum antibodies, lacked sensitivity in sera from patients with primary syphilis.

Antibodies, Bacterial↗
PubMed1980

Development of the epithelium of the middle ear. Electron microscopic study of fine structure, including junctional complexes and basal lamina.

A detailed light and electron microscopic study of the development of the middle ear lining epithelium of the rat was undertaken in order to determine whether a portion of the middle ear lining is normally derived from a condensation of mesenchymal connective tissue. We learned that pharyngeal epithelium outpouches early in development and persists during the formation and growth of the ossicles and inner ear structures in a relatively constant anatomic relationship. We found no evidence of a contribution of mesodermal tissue to the lining epithelium itself. Certain features of the junctional complexes between adjacent cells were used as a means of identifying pharyngeal and middle ear epithelial cells. It is concluded that at no time is connective tissue found within the middle ear space (as defined by its epithelial limits); pneumatization occurs by absorption of mesenchymal tissue that occupied the space between the outer part of the epithelium and bone structures.

Age Factors↗
PubMed1979

Problems affecting performance of the fluorescent treponemal antibody-absorption test for syphilis.

Immunofluorescent staining of Treponema pallidum was studied to clarify the effect of three factors on the results of the fluorescent treponemal antibody-absorption test: (i) heat inactivation of sera at 56 degrees C for 30 min before testing, (ii) use of multicircle slides, and (iii) tungsten illumination to visualize and assess unstained treponemes on reactive as well as nonreactive smears. It was found that serum inactivation before testing was not necessary for detection of immunoglobin G antibody, but an immunoglobulin M prozone was detected in unheated serum. On multicircle slides, it was demonstrated that a false-positive reaction could be obtained in 30 s at 37 and 25 degrees C if a smear where a nonreactive serum had been placed was crossed by a strongly reactive serum from another circle. Tungsten illumination proved necessary for correct assessment of unstained treponemes on all fluorescent treponemal antibody-aborption test smears, reactive or nonreactive. The possible role of these factors in incorrect fluorescent treponemal antibody-absorption test results is discussed.

Antibodies, Bacterial↗
PubMed1978

Hemagglutination tests for syphilis antibody.

In a study of serodiagnosis of syphilis, the authors compared the specificities and sensitivities of two hemagglutination tests, a sheep-erythrocyte test (MHA-TP) and a trukey-erythrocyte test (TPHA), with those of the Fluorescent Treponemal Antibody-Absorption (FTA-ABS) test. In tests of sera from 935 patients without syphilis, the MHA-TP, TPHA, and FTA-ABS tests were reactive for 0.96, 0, and 1.3% respectively. The false-positive results were usually transient and not associated with underlying illness. For the 68 patients with syphilis, the MHA-TP test was as sensitive as the FTA-ABS test in all stages except untreated primary disease. The TPHA test appeared to be undersensitive, and testing of follow-up sera from persons with latent syphilis showed unexplained conversion of false-negative TPHA results to reactive results. Reproducibilities of the two hemagglutination tests were comparable. The MHA-TP test is a valuable confirmatory test for syphilis. Further study is needed before the use of the TPHA test can be recommended.

Animals↗