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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 235 records · Page 13Linked to original sources
PubMed1988

Echo-planar pediatric imager.

Practical constraints make it difficult to build large-aperture echo-planar magnetic resonance (MR) imagers. The implementation of a pediatric imager and its performance are described. Spatial resolution and signal-to-noise levels comparable to those of 1982 state-of-the-art MR imagers have been achieved in imaging times of 0.05-0.15 seconds. T1 and T2 information are obtainable in the echo-planar mode. A major issue is that of chemical-shift displacements.

Child↗
PubMed1988

Signal-to-noise ratio and section thickness in two-dimensional versus three-dimensional Fourier transform MR imaging.

The efficiency and quality of three-dimensional Fourier transform (3DFT) magnetic resonance imaging were evaluated and compared with those of 2DFT imaging. For a fixed imaging time and number of sections, 3DFT imaging with conventional spin echoes always had a worse signal-to-noise ratio (S/N) than did 2DFT imaging, when both were optimized with respect to choice of repetition time (TR). With partial-flip magnetic resonance (MR) imaging, S/N was nearly equal for 2DFT and 3DFT imaging when both were optimized with respect to TR and flip angle. 3DFT imaging can have cross-section artifacts that exceed those of 2DFT imaging. For very thin sections these artifacts may be lessened, and 3DFT imaging can achieve this with smaller gradient pulses. Over-all, 3DFT imaging was found to be advantageous only for the very-thin-section imaging and in combination with partial-flip MR imaging.

Fourier Analysis↗
PubMed1988

Characterization of MR spectroscopic imaging of the human head and limb at 2.0 T.

Using section-select and phase-encoding gradients, the authors obtained phosphorus chemical shift images of the human head and limb. Phosphorus spectra were acquired from planar sections divided into voxels as small as 7 cm3 in calf muscle and 27 cm3 in brain, with total examination times, including setup and proton locator imaging, of roughly 1 hour. Both spin-echo and free induction decay (FID) methods were employed; the FID gave superior results. Signal-to-noise ratios for the beta-adenosine triphosphate and phosphocreatine resonances were as high as 10:1 and 13:1 from volumes of 27 cm3 in brain.

Brain↗
PubMed1988

Rhinocerebral zygomycosis caused by Saksenaea vasiformis.

A fatal rhinocerebral zygomycotic infection caused by Saksenaea vasiformis in a 71-year-old man was diagnosed based on the presence of broad, infrequently septate, branched, hyaline hyphae in tissue obtained from the right and left base of the skull, soft tissue, both maxillary sinuses and the sphenoid sinus; isolation of S. vasiformis from the tissue; and demonstration of mucoraceous antibodies by enzyme-linked immunosorbent assay. Fluorescent antibody studies carried out with a Rhizopus arrhizus conjugate, stained hyphal fragments in tissue with a 2+ intensity.

Aged↗
PubMed1988

An immunological procedure for the rapid identification of Phaeoannellomyces werneckii.

Phaeoannellomyces werneckii is identified on the basis of its annellidic conidiogenous cells and the production of two-celled conidia. Without the proper recognition of its annellidic mode of conidiogenesis, isolates of P. werneckii can be confused with other species of Phaeococcomyces, Exophiala, and Scolecobasidium constrictum. To overcome this problem, we developed exoantigen reagents capable of specifically identifying P. werneckii. Rabbit P. werneckii antiserum was rendered specific by adsorptions with antigens of Exophiala jeanselmei serotype 1, Exophiala moniliae, and Wangiella dermatitidis. Eighty-two dematiaceous yeast-like fungi, including 18 P. werneckii cultures, were tested in the immunodiffusion test against P. werneckii antisera. Exoantigen tests permitted the rapid and specific identification of the 18 P. werneckii isolates. Negative results were obtained with the 64 heterologous antigen extracts.

Antigens, Fungal↗
PubMed1988

Epidemiology of inflammatory bowel disease in a defined northern California population.

The epidemiology of inflammatory bowel disease is described among the more than 1.5 million members of the Kaiser Permanente Medical Care Program (KPMCP) in northern California. We reviewed a 20% random sample of the medical records of 2,067 persons first admitted to hospital in the period 1971 through 1982 with codes indicating inflammatory bowel disease. We also examined all new outpatient cases for a 1-year period from records at the Oakland KPMCP facility. Criteria used to establish valid cases adhered to standards used in previous studies but were revised to reflect current diagnostic methods. The disadvantages of using hospital discharge data have been identified and quantified. In this population, only 21% of ambulatory patients with inflammatory bowel disease were admitted to hospital in a 3 1/2-year period. There was no difference in the incidence of the disorder by sex or between whites and blacks, but it was rare in Asians. A bimodal age distribution was suggested for Crohn's disease but not for ulcerative colitis. During the 12 years of this study, rates of hospital admissions for ulcerative colitis decreased and for Crohn's disease were slightly increased.

Adolescent↗
PubMed1987

Serologic studies in the diagnosis and management of meningitis due to Sporothrix schenckii.

Eight patients have previously been reported to have central nervous system infections caused by Sporothrix schenckii. In those patients the fungus proved quite difficult to culture, delaying correct diagnosis and treatment. We describe seven additional patients with sporotrichosis meningitis, all of whom had antibody to this fungus in cerebrospinal fluid and serum. The antibody in the cerebrospinal fluid was most likely produced locally, as evidenced by its oligoclonality and the relatively high ratio of immunoglobulin to albumin in the cerebrospinal fluid as compared with the serum. Only one of these seven patients, who had active sporotrichosis of the knee joint, had obvious extrameningeal infection. None of 130 patients with meningitis known to be caused by other agents and none of 170 patients with other neurologic disorders had antibody to S. schenckii in their cerebrospinal fluid. We suggest that cerebrospinal fluid should be tested for S. schenckii antibody (in addition to other fungal agents) in any patient with chronic meningitis for which no cause is discovered by the usual diagnostic tests.

Adult↗
PubMed1987

Treatment of cryptococcal meningitis with combination amphotericin B and flucytosine for four as compared with six weeks.

One hundred ninety-four patients with cryptococcal meningitis were enrolled in a multicenter, prospective, randomized clinical trial to compare the efficacy and toxicity of four as compared with six weeks of combination amphotericin B and flucytosine therapy. Among 91 patients who met preestablished criteria for randomization, cure or improvement was noted in 75 percent of those treated for four weeks and in 85 percent of those treated for six weeks. The estimated relapse rate for the four-week regimen was higher--27 as compared with 16 percent--whereas the incidence of toxic effects for the two regimens was similar--44 as compared with 43 percent. Among 23 transplant recipients, 4 of 5 treated for four weeks relapsed, leading to the decision to treat the rest of the group for six weeks. Only 3 of the 18 treated for six weeks relapsed. In a third group of 80 patients, the protocol was not followed during the initial four weeks, and these patients were not randomized. Thirty-eight died or relapsed. Multifactorial analysis of pretreatment factors for all 194 patients identified three significant predictors (P less than 0.05) of a favorable response: headache as a symptom, normal mental status, and a cerebrospinal fluid white-cell count above 20 per cubic millimeter. These and other findings in this study are consistent with the view that the four-week regimen should be reserved for patients who have meningitis without neurologic complications, underlying disease, or immunosuppressive therapy; a pretreatment cerebrospinal fluid white-cell count above 20 per cubic millimeter and a serum cryptococcal antigen titer below 1:32; and at four weeks of therapy, a negative cerebrospinal fluid India ink preparation and serum and cerebrospinal fluid cryptococcal-antigen titers below 1:8. Patients who do not meet these criteria should receive at least six weeks of therapy.

Adolescent↗
PubMed1987

Lack of response to suramin in patients with AIDS and AIDS-related complex.

Forty-one homosexual men with the acquired immune deficiency syndrome (AIDS) or AIDS-related complex were treated with 0.5, 1.0, or 1.5 g of suramin weekly for up to six months. In no patient was evidence of symptomatic improvement or regression of Kaposi's sarcoma shown. Opportunistic infections developed in 16 patients during therapy. Only six patients (15 percent) became human immunodeficiency virus (HIV) culture-negative during treatment, despite documentation of adequate serum suramin levels. All but one of these six have had disease progression. Decreases in the numbers of total T4 cells with time were observed in both AIDS and AIDS-related complex subgroups. Toxicity was significant and consisted of fatigue, fever, and hepatic and renal dysfunction, all of which were observed most frequently with the 1.0 or 1.5 g dosages. Fatal hepatic failure developed in two patients, and adrenal insufficiency was documented in eight patients. Suramin is a toxic agent that shows no virologic, immunologic, or clinical benefit in patients with HIV-related disease.

AIDS-Related Complex↗
PubMed1987

The utility of principal component analysis for the image display of brain lesions. A preliminary, comparative study.

Principal component analysis (PCA), a common tool from multivariate statistical analysis, has been implemented into the computer display system of a MR imaging device. PCA allows the calculation of images in which the information in a defined region of interest inherent in the basic acquired images is condensed. PCA image calculation has been applied to acquired MR studies of 13 patients with brain lesions. The appearance of the brain lesions on the resultant PCA images was scored in comparison to the acquired images before and after administration of Gd-DTPA as well as to other calculated images including T1, T2, hydrogen density, and contrast-optimized images. The conspicuity of a lesion and the number of distinguishable components within a lesion were slightly superior on PCA than on the acquired images. PCA is an analytical tool for MR imaging that should be helpful in revealing information that is inherent in, but not readily visible on, standard acquired MR images.

Brain Neoplasms↗
PubMed1987

Mixed mesodermal tumor of the uterus (RJ-984): case report and in vitro study.

This report describes the establishment of a cell line of a human uterine mixed mesodermal tumor. The tumor of origin derived from a hysterectomy specimen, has been maintained for 14 months in vitro and continues to grow as an established cell line. The original tumor as well as the cell line exhibited no estrogen receptors. alpha-Fetoprotein was not detected in the cultured cells or in the spent culture medium. Karyotyping revealed 46 XX chromosome complement with a balanced 11-16 translocation. This is the first documentation of such a chromosome abnormality in a genital tract carcinoma. Steroids inhibited cell growth at high (10.0 micrograms/ml) concentrations. This cell line continues to be studied and further characterized. The cell line is readily available for study of this aggressive human neoplasm.

Cell Division↗
PubMed1987

Evaluation of commercial serologic test reagents for immunoidentification of medically important aspergilli.

We evaluated commercial serodiagnostic test reagents from Greer Laboratories (GL), Lenoir, NC; Immuno-mycologics, Inc. (IMI), Norman, OK; and Scott Laboratories (SL), Fiskville, RI; for their ability to detect Aspergillus spp. exoantigens and group them in their proper series. We detected 87 culture extracts from coded cultures of Aspergillus groups and heterologous fungi against anti-A. fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus sera in the presence of their corresponding antigens. Parallel control studies were performed using serological reagents from both laboratories. The IMI reagents accurately grouped all the isolates. The A. nidulans and A. terreus reactions, however, were significantly weaker than those noted with the control reagents. GL and SL do not supply A. nidulans and A. terreus reagents. Their available reagents correctly grouped the A. fumigatus, A. flavus, and A. niger isolates. Our results indicate that the commercial serodiagnostic reagents for aspergillosis can be effectively used to accurately immunoidentify the medically important Aspergillus spp.

Aspergillus↗