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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 487 records · Page 27Linked to original sources
PubMed1968

Value and interpretation of serological tests for the diagnosis of cryptococcosis.

MAXIMAL SEROLOGICAL DIAGNOSIS OF CRYPTOCOCCOSIS MAY BE ACCOMPLISHED THROUGH THE CONCURRENT USE OF THREE TESTS: the latex agglutination (LA) test for cryptococcal antigen, and the indirect fluorescent antibody (IFA) and tube agglutination (TA) tests for Cryptococcus neoformans antibodies. These tests were applied to 141 serum and cerebral spinal fluid specimens from 66 culturally proven cases of cryptococcosis and to 42 sera from normal subjects and from patients with other systemic mycotic diseases. The LA test was sensitive and completely specific; of the sera from proven cases, 55% were positive. With the TA test, 37% of the specimens were positive and the test was highly specific. With the IFA test, 38% of the specimens were positive and the test appears to be the least specific of the three. Cross-reactions were most evident with blastomycosis and histoplasmosis case sera. When the three tests were used concurrently, 87% of the cryptococcosis case specimens were positive and permitted a presumptive diagnosis of C. neoformans infections in 61 (92%) of the 66 patients whose specimens were examined.

Amphotericin B↗
PubMed1968

Fluorescent-antibody reagent for the identification of Cryptococcus neoformans.

A sensitive and diagnostically applicable conjugate for the rapid and accurate detection and identification of Cryptococcus neoformans has been developed. C. neoformans rabbit antisera were produced by 14 daily intravenous injections of 36 million cells for a total dosage of approximately 500 million cells. Cross-staining reactions with species of Cryptococcus other than C. neoformans, as well as with Candida species, were eliminated by adsorption of the C. neoformans conjugate with cells of C. diffluens and C. krusei.

Adsorption↗
PubMed1968

Development and use of a polyvalent conjugate to differentiate Histoplasma capsulatum and Histoplasma duboisii from other pathogens.

Previous investigations have demonstrated the existence of five Histoplasma capsulatum serotypes. Available specific fluorescent-antibody reagents stain only four of the five serotypes. Antibodies produced against the most complete H. capsulatum serotype were labeled with fluorescein isothiocyanate to develop a reagent specific for H. capsulatum that was reactive with all the known serotypes. The unadsorbed reagent not only stained all the H. capsulatum serotypes, but it also stained cultures of Blastomyces dermatitidis, H. duboisii, several Candida species, and a variety of other fungi. Adsorption of the conjugate with antigens of C. albicans produced a reagent that intensely stained only H. capsulatum, H. duboisii, and B. dermatitidis. Differentiation of B. dermatitidis from the Histoplasma species was accomplished by application of a B. dermatitidis specific fluorescent antibody to antigens positive with the H. capsulatum reagent. At present, differentiation of H. capsulatum from H. duboisii may be accomplished only by animal inoculation. Our data substantiate the antigenic relationships hypothesized earlier, and they indicate that H. capsulatum shares at least two antigens with the other fungi that were studied.

Antibodies↗
PubMed1967

Effects of a single histoplasmin skin test on the serological diagnosis of histoplasmosis.

Numerous reports have indicated that a single histoplasmin skin test may stimulate humoral antibodies to Histoplasma capsulatum antigens in histoplasmin-hypersensitive individuals. Although these investigations concur that antibody elevations are evoked, they vary in the reported degree of incidence and response induced, and they cast doubt on the interpretation of serological tests in the diagnosis of histoplasmosis. Histoplasmin-hypersensitive subjects (114) were bled prior to administration of the skin test, 2 days later, at the time this test was read, and 15 and 30 days after testing. No significant antibody titers were observed at 2 days. At 15- and 30-day intervals, only 17 (15%) of the subjects demonstrated circulating antibodies. All 17 showed agar gel bands; 5 demonstrated no complement-fixation (CF) titers, 10 produced CF antibodies ranging from 1:8 to 1:16, and 2 demonstrated titers of 1:32. The data suggest that skin testing does not interfere significantly with antibody levels in sera drawn approximately 2 days after administration of antigen. However, since titers as high as 1:32 were obtained at later intervals, such reactions should be evaluated cautiously and only after consideration of clinical findings.

Antibody Formation↗
PubMed1966

Occurrence of serotypes among Histoplasma capsulatum strains.

Kaufman, Leo (Communicable Disease Center, Atlanta, Ga.), and Sharon Blumer. Occurrence of serotypes among Histoplasma capsulatum strains. J. Bacteriol. 91:1434-1439. 1966.-Extensive studies with a fluorescent antibody specific for the yeast form of Histoplasma capsulatum indicated that, although most strains of H. capsulatum stained intensely, others stained weakly and some did not stain. These observations suggested that antigenic variants of the fungus existed. To test this hypothesis, reciprocal cross-staining and adsorption procedures were performed with fluorescein-labeled antiglobulins to four strains of H. capsulatum. Fifty-six strains of H. capsulatum and 11 strains of H. duboisii were studied. The data indicate that at least five serotypes of H. capsulatum occur. One is closely related antigenically to H. duboisii and Blastomyces dermatitidis.

Adsorption↗
PubMedDate not supplied

Advances in neuromagnetic instrumentation and studies of spontaneous brain activity.

Rapid progress in neuromagnetic technology has been achieved during the past two years with the introduction of a method for accurately indicating magnetic sensor locations with respect to a head-based coordinate system and the advent of refrigerator-cooled sensors and larger arrays of sensors. These make possible the real-time monitoring of evoked activity at several widely separated locations over the scalp, thus revealing sequential activity in, e.g., sensory-motor tasks. Arrays of magnetic sensors also provide sufficient information to locate the sources of spontaneous activity, such as alpha rhythm. The locations of discrete generators (alphons) of individual alpha spindles is now possible with an array of 14 sensors. Mapping techniques with a 5-sensor system have revealed preferential suppression of alpha activity within certain regions of the occipital lobe to tasks involving mental comparisons of abstract figures. These studies provide evidence that the machinery of visual cortex is involved in mental imagery.

Alpha Rhythm↗
PubMedDate not supplied

Pulmonary cryptococcosis due to a capsule-deficient strain confused with metastatic lung cancer.

A patient with hepatocellular cancer developed pulmonary cryptococcosis due to infection with a capsule-deficient Cryptococcus neoformans. Pulmonary lesions initially diagnosed as metastatic cancer by chest x-ray film and CT scan were subsequently found to be fungal granulomas by autopsy. Although morphologic studies of the fungi were insufficient to render a specific mycologic diagnosis because of the absence of encapsulated yeasts, fluorescent antibody studies confirmed the diagnosis of cryptococcosis. The use of various stains and electron microscopy for the pathological differential diagnosis of cryptococcosis caused by capsule-deficient yeasts is discussed.

Carcinoma, Hepatocellular↗