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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 433 records · Page 24Linked to original sources
PubMed1978

An epidemic of histoplasmosis on the Isthmus of Panama.

Forty-seven men on the Isthmus of Panama were exposed to histoplasmosis in an old bunker inhabited by bats. The resulting epidemic was studied with serial clinical, serological, and radiological examinations. Thirty-seven (78.7%) of the men showed serological evidence of infection and 26 (70.3%) had symptoms. Incubation periods ranged from 4 to 30 days. A general relationship between severity of illness and degree of exposure was noted. The agar gel diffusion test for precipitin antibodies was more sensitive than the complement-fixation test or slide test in detecting infection with Histoplasma capsulatum. Decontamination procedures and environmental studies are described.

Amphotericin B↗
PubMed1978

An outbreak of histoplasmosis at an Arkansas courthouse with five cases of probable reinfection.

An outbreak of histoplasmosis occurred at a county courthouse in Arkansas in July, 1975. Fifty cases were identified by symptoms and positive complement fixation (CF) tests and 18 others by the clinical findings alone. Only three positive CF tests (greater than or equal to 1:8) were found in a control group of 55 unexposed persons of the same age. The attack rate for 84 courthouse employees was 52%. Histoplasma capsulatum was isolated from the sputum of two cases, and from bird droppings which had been dumped from the roof of the courthouse two weeks before the epidemic's peak. Window air conditioners apparently helped to distribute infectious particles throughout the building. Nine exposed people had pulmonary calcifications and a negative tuberculin test that were taken as presumptive evidence of previous histoplasmosis. Five (55%) of these became ill. Exposed persons without pulmonary calcifications had an attack rate of 85%. The reinfected cases during convalescence had higher serum CF titers but not larger histoplasmin skin test diameters than the rest of the cases. A microdroplet aerosol of cooking oil was used to simulate air flow patterns during the exposure, and the results agreed with the hypothesized means of infection.

Adult↗
PubMed1977

Characterization of immunoglobulin classes of human antibodies to cryptococcus neoformans.

Immunoglobulin G (IgG), immunoglobulin M (IgM) and immunoglobulin A (IgA) levels were determined by radial immunodiffusion techniques in sera from 11 patients with cryptococcosis. Most specimens showed increased levels of IgM. Studies with fluorescein-labeled monospecific antihuman IgG and IgM, however, indicated that IgG was the immunoglobulin reactive in the indirect fluorescent antibody (IFA) test. In addition, cross-reacting sera from mycotic infections other than cryptococcosis were also shown to contain IFA antibodies of the IgG class. Sera treated with 2-mercaptoethanol continued to react in both the IFA test and the tube agglutination test. No correlation could be established between IgG AND IgM concentrations and serological reactivity in the sera evaluated in this study.

Antibodies, Fungal↗
PubMed1977

Antigenic, chemical, and structural properties of cell walls of Histoplasma capsulatum yeast-form chemotypes 1 and 2 after serial enzymatic hydrolysis.

Cell walls of Histoplasma capsulatum yeast-form chemotypes 1 (chem 1) and 2 (chem 2) treated sequentially with several polysaccharolytic enzymes and Pronase yielded soluble, nondialyzable polysaccharides at each step, which were analyzed for monosaccharides, protein composition, and serological activity. Polysaccharide recovered after digestion of chem 1 walls with beta(1-->3)-glucanase contained glucose > mannose > glucosamine > galactose. This fraction (chem 1 betaG(1)) was analyzed by polyacrylamide gel electrophoresis and contained a component having an apparent molecular weight of 120,000. The chem 1 betaG(1) fraction was reactive in immunodiffusion (ID), producing an immune precipitate not identical to the H and M factors of histoplasmin. In a side-by-side ID comparison with extracts of chem 2, the chem 1 betaG(1) antigen contained an additional determinant not found in chem 2 extracts when tested with goat antiserum to H. capsulatum. Therefore, the chem 1 antigen gave preliminary ID evidence of antigenic group specificity. A chemical difference observed was the absence of glucosamine from chem 2 polysaccharide. In complement fixation (CF) tests, 9 of 17 sera from human histoplasmosis patients reacted with chem 1 betaG(1), but some cross-reactivity with sera of patients with other systemic mycoses occurred. The immunoelectrophoretic patterns of chem 1 wall-derived polysaccharides showed a marked shift in mobility after Pronase digestion, implying the presence of covalent peptides. The ultrastructural appearance and serological activity of intact walls and enzyme-resistant mural cores were also studied. The surface of the mural cores of both chemotypes was perforated and frayed. In shadow-cast preparations both fibrillar and globular areas persisted in the mural cores. The CF end point serum dilutions showed an increase after alpha- and beta-glucanase extractions of chem 2 walls and fourfold reduction after Pronase digestion. The mural cores of both chemotypes were still reactive in CF tests and retained some ability to bind fluorescent antibody. The chem 1 mural core reacted with specific fluorescein-labeled H. capsulatum antiglobulins produced by adsorption with Blastomyces dermatitidis, thus indicating at least partial retention of H. capsulatum-specific factors. The presence of galactose, mannose, and glucose was detected in the mural cores as well as enriched levels of amino sugar, despite exposure to chitinase.

Antigens, Fungal↗
PubMed1977

Immunological procedure for the rapid and specific identification of Coccidioides immitis cultures.

An immunological procedure for the rapid and specific identification of Coccidioides immitis isolates has been developed. The specificity of the procedure is based on the fact that C. immitis produces antigens that are not produced by morphologically similar fungi. The procedure involved the transfer of heavy mold-form inocula to flasks that contained small volumes of brain heart infusion broth. Shake cultures were grown at 25 degrees C on a gyratory shaker at 150 rpm. The concentrated supernatant antigens so obtained from broth cultures were tested in parallel with coccidioidin by a microimmunodiffusion technique against C. immitis antiserum. The ability of the immunological procedure to identify C. immitis cultures was evaluated by testing the supernatant antigens of 166 unknown isolates, many of which, by gross or microscopic examination or both, resembled C. immitis or belonged to the family Gymnoascaceae. Each culture was also identified by conventional laboratory procedures. Comparative evaluation showed that the immunological test for C. immitis was 100% sensitive and specific. The diagnostic precipitin bands that were produced by the interaction of the C. immitis supernatants and antisera were shown to consist of (i) a heat-stable antigen comparable to that active in the tube precipitin test and (ii) two heat-labile antigens, one of which was associated with complement fixation reactivity. With pure cultures, this immunological procedure permitted the identification of C. immitis isolates within 5 days.

Antigens, Fungal↗
PubMed1977

Laboratory evaluation of serological tests for systemic candidiasis: a cooperative study.

Three serological tests for candidiasis, agar gel diffusion (AGD-1), whole cell agglutination (AGGL-1), and latex agglutination (LAT), were evaluated by six laboratories with 100 coded sera. In addition, each of six laboratories performed a test of its choice, either the AGD-2, the AGD-3, the AGGL-2, or one of three counterimmunoelectrophoresis (CEP) methods (CEP-1, CEP-2, and CEP-3). Results are presented by laboratory for a group of 53 "candida-involved" cases (33 proven, 14 presumptive, and 6 probable) and 47 negative controls (41 normal and 6 other disease states). The AGD-1 test produced an overall average of 85.1% positive results in the candida-involved group and 5.0% positives in the control group. The LAT produced an overall average of 89.0% positives in the candida-involved group and 17.4% positives in the controls. The AGGL-1 test produced an overall average of 63.8% positives in the candida-involved group, with 12.3% positives in the controls. In the individual tests, the best performance was shown by the CEP-3 test (92.5% positives in the candida-involved group and 2.1% positives in controls) and the CEP-1 test (88.7% positive in the candida-involved group and no positives in the controls). The tests with the highest sensitivity were the AGGL-2 and CEP-2 (94.3 and 96.2%, respectively). These tests were also the least specific (80.9 and 76.6%, respectively). In the three common tests, the AGD-1 was the most reproducible, whereas the AGGL-1 produced considerable laboratory-to-laboratory variation. Since cell-free extracts of mechanically disrupted C. albicans were used for the LAT and all the AGD and CEP tests, the difference in performance was considered to be mainly due to antigenic composition and the conditions of the test. The results of this study confirm the value of serological tests for the diagnosis of systemic candidiasis, but point out the need for standardized reagents.

Agglutination Tests↗
PubMed1977

Solid-phase competitive-binding radioimmunoassay for detecting antibody to the M antigen of histoplasmin.

A radioimmunoassay (RIA) was designed and compared with complement fixation and immunodiffusion tests for their relative ability to detect antibodies in sera of histoplasmosis patients. M antigen, purified from histoplasmin, was fixed to microtiter wells as the solid phase, and specific rabbit 125I-labeled anti-M globulin was the source of indicator antibodies. The optimal concentrations for the competitive-binding assay were 1.6 ng per well for M antigen and 650 ng per well for the 125I-labeled anti-M globulin. A panel of sera from 29 histoplasmosis patients and from patients with other mycoses was screened for RIA activity and in complement fixation and immunodiffusion tests that used histoplasmin and Histoplasma capsulatum yeast-form antigens. The sera of 22 histoplasmosis patients reacted in the RIA, 21 in the complement fixation, and 16 in the immunodiffusion tests. Sera of patients with other mycotic infections did not react in the RIA, with the exception of those of one blastomycosis patient and one candidiasis patient. The RIA could be modified to quantitate M antigen; as little as 125 pg could be detected. The evaluation of this panel of histoplasmosis patients' sera showed that the RIA was about equivalent in sensitivity to the complement fixation test. Some advantages of the RIA over the complement fixation test were that RIA was less prone to cross-reactions and gave better quantitation of low-titered sera. The RIA was a 1-day test, was not hindered by the anti-complementary activity of some sera, and could be modified to quantitate minute amounts of M antigen.

Antibodies, Fungal↗
PubMed1976

The fusion illusion.

Explore the source record for details and available documents.

Discrimination, Psychological↗
PubMed1976

Specific immunological test for the rapid identification of members of the genus Histoplasma.

A sensitive and specific immunological method was developed for rapid identification of the mycelial forms of Histoplasma capsulatum var. capsulatum, H. capsulatum var. duboisii, and H. farciminosum and for separation of these pathogenic fungi from morphologically similar hyphomycetes and other fungal pathogens. This method is based on the fact that all of the Histoplasma spp. produce H and M histoplasmin antigens, whereas the other fungi do not. Inocula consisting of heavy mycelial growth from a pure, full-grown culture were transferred into flasks containing small volumes of brain heart infusion broth. These cultures were placed on a shaker and grown at 25 C. Using the micro-immunodiffusion technique and antisera containing antibodies to H and M precipitinogens, we detected exoantigens in 3-day-old brain heart infusion culture supernatants concentrated 25 and 50 times. The ability of the procedure to identify Histoplasma spp. was evaluated by testing 96 unknown mycelial cultures that grossly or microscopically resembled Histoplasma spp. Three- and six-day-old concentrated culture supernatants prepared from each unknown were tested against rabbit anti-Arthroderma tuberculatum, Chrysosporium keratinophilum, H. capsulatum var. duboisii, and Corynascus (Thielavia) sepedonium sera and human histoplasmosis case serum. Each unknown was also identified by conventional laboratory procedures involving cultural and, where necessary, in vivo studies. In the comparative evaluation the immunological test was observed to be 100% sensitive. It permitted the accurate generic identification of the Histoplasma spp. within 5 days, in contrast to the average of 33 days required by the routine mycological procedure.

Antigens, Fungal↗
PubMed1976

Low cost intrathyroidal iodine quantification with a fluorescent scanner.

A thyroid fluorescent scanner has proven to be useful for imaging thyroids in cases where isotope scans are contraindicated. Minor modifications of a commercially available scanner make possible total intrathyroidal quantification, which aids in the differentiation between primary and secondary hypothyroidism and in the diagnosis of thyroiditis.

Costs and Cost Analysis↗
PubMed1976

The measurement of circulating red cell volume using nonradioactive cesium and fluorescent excitation analysis.

Nonradioactive cesium, as an analogue of potassium, has been used to label autologous red blood cells for determination of the red cell volume in man. The initial and the equilibration concentrations of cesium are assayed by fluorescent excitation analysis (FEA), using a 600 mCi 241Americium source and a Si(Li) detector with a 1024-channel analyzer. Comparative studies with 51Chromium in 13 rabbits showed good correlation, but the intracellular cesium concentration achieved by simple incubation with 2.6 per cent cesium chloride solution was too low to be of practical value in humans. Incubation of the human red blood cells with 50 mug per milliliter of Nystatin in 2.6 per cent cesium chloride opened reversible "pores" in the red cell membrane which permitted high intracellular cesium labeling without demonstrable red cell damage. The cesium red cell volumes in 11 random human subjects differed from the 51Chromium red cell volumes by only 0.2 +/- 4.5 per cent and 2.5 +/- 7.6 per cent at blood sampling times of 10 minutes and 40 minutes, respectively. Blood cesium levels fell with a clearance half-time of 31.5 hours in 4 rabbits, and 2.4 days in 1 normal human. Fluorescent excitation analysis of cesium-labeled autologous red blood cells permits accurate determination of the red cell volume in man without associated patient radiation, thus making the procedure much more acceptable for children, pregnant women, normal volunteers, and for repeated studies in the same individual.

Blood Volume Determination↗
PubMed1975

Visually evoked magnetic fields of the human brain.

Magnetic field variations from the human brain produced by visual stimulation have been observed in a normal laboratory setting with a superconducting quantum interference device and no magnetic shielding of the subject. Previously unknown temporal and spatial features of the field near the scalp are reported.

Brain↗