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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 253 records · Page 14Linked to original sources
PubMed1987

Construction activity: an independent risk factor for invasive aspergillosis and zygomycosis in patients with hematologic malignancy.

Between November 1982 and July 1984, five patients at a 110-bed pediatric hospital were diagnosed with invasive filamentous fungal infection; three had invasive aspergillosis (IA) and two had invasive zygomycosis (IZ). All five had underlying hematologic malignancy (HM). In a case-control study, these five HM patients (cases) were compared to 10 autopsied HM patients without evidence of aspergillosis or zygomycosis (controls). Cases and controls did not differ in underlying disease or in the degree of immunosuppression, as measured by duration of granulocytopenia and number of platelet transfusions. However, case-patients were more likely than controls to have been hospitalized during the construction of a hospital addition (p less than 0.02, Fisher's exact test [FET]). Four (80%) of five HM patients autopsied during the period of construction had IA or IZ compared with one (5%) of 21 autopsied before construction began (p = 0.001, FET). These findings suggest that, in a population of comparably immunosuppressed patients, construction activity may represent an independent risk factor for IA or IZ. Hospitals caring for such patients should take precautions which minimize exposure of these patients to construction or renovation activity.

Adolescent↗
PubMed1987

High resolution MR imaging of peripheral joints using a quadrature coil at 0.35 T.

The utility of a specially dedicated quadrature detection (QD) mode limb coil for the MR evaluation of peripheral joints has been evaluated. High resolution images of the knee, elbow, wrist and ankle provided excellent anatomical delineation of the cortical and medullary bone, cartilage, ligaments and menisci over a homogeneous field of view. Pathological conditions including meniscal injury, fracture and osteonecrosis were accurately detected. The QD limb coil can be advantageously used for the MR evaluation of peripheral joints at an intermediate field strength.

Evaluation Studies as Topic↗
PubMed1987

Serological tests for blastomycosis: assessments during a large point-source outbreak in Wisconsin.

Enzyme immunoassay (EIA), immunodiffusion (ID), and complement fixation (CF) tests for antibody to the A antigen of Blastomyces dermatitidis were assessed in 47 patients in an epidemic of blastomycosis and in 89 control subjects with lower respiratory tract illness. Antibody was detected by EIA, ID, and CF in 77%, 28%, and 9% of the patients, respectively. EIA titers ranged from 1:8-1:512 (median titer, 1:128). Antibody detected by ID or CF was always detectable by EIA. Antibody was detected by EIA 13 days after illness onset, and the peak seroprevalence rate and geometric mean titer occurred 50-70 days after onset. Antifungal therapy produced a significant decline in antibody titer by approximately six months after onset. Seven (8%) control subjects had detectable antibody, six had EIA titers of 1:8, and one had a titer of 1:16. The specificities for EIA, ID, and CF were 92%, 100%, and 100%, respectively. The EIA provides a significant advance in serodiagnostic testing for blastomycosis and can be used in an outbreak setting as an epidemiological tool to identify acute B. dermatitidis infection; titers greater than or equal to 1:32 strongly support the diagnosis, whereas titers of 1:8 or 1:16 are suggestive.

Adult↗
PubMed1987

The value of relaxation times and density measurements in clinical MRI.

The hope that MRI relaxation time signatures would identify tissues, specifically, malignancies, has not been realized. This is due much less to measurement inaccuracies than to a large intrinsic variability and overlaps between malignancies and many benign pathologies. Neither has there been success in predicting relaxation times from basic tissue compositions. Nevertheless, MRI provides a qualitative measure of tissue hydration, and of flow, on the basis of relaxation times. Furthermore, pixel-by-pixel maps of relaxation times have proven useful in understanding the MRI process, in predicting the efficacy of untried techniques, and replace, in many circumstances, the need for acquisition of images with diverse sequencing parameters.

Body Water↗
PubMed1987

Antigenic relationship between the animal and human pathogen Pythium insidiosum and nonpathogenic Pythium species.

Identification of the newly named pathogenic oomycete Pythium insidiosum and its differentiation from other Pythium species by morphologic criteria alone can be difficult and time-consuming. Antigenic analysis by fluorescent-antibody and immunodiffusion precipitin techniques demonstrated that the P. insidiosum isolates that cause pythiosis in dogs, horses, and humans are identical and that they were distinguishable from other Pythium species by these means. The immunologic data agreed with the morphologic data. This indicated that the animal and human isolates belonged to a single species, P. insidiosum. Fluorescent-antibody and immunodiffusion reagents were developed for the specific identification of P. insidiosum.

Animals↗
PubMed1987

Evaluation of Leathers-Awasthi medium for identifying Coccidioides immitis isolates.

Leathers-Awasthi medium (LAM) has been recommended for the definitive identification of Coccidioides immitis isolates recovered from clinical specimens. Studies were undertaken to determine the diagnostic reliability of this medium for identifying fungal cultures. A total of 62 fungi, representing 13 C. immitis isolates and 49 similar pathogenic and saprophytic fungi, were tested in parallel by the LAM and exoantigen tests. All of the 13 C. immitis isolates were positive by the exoantigen test, whereas only 11 were positive on LAM. Of the 49 other fungal isolates, 29 were positive on LAM whereas none was positive by the exoantigen test. LAM does not permit the unequivocal identification of C. immitis isolates.

Antigens, Fungal↗
PubMed1987

Specific and rapid identification of medically important fungi by exoantigen detection.

Within a decade of its introduction, the exoantigen technique has won general acceptance for accurate and rapid identification of fungal pathogens. This acceptance is emphasized by the fact that positive exoantigen results obtained with the dimorphic pathogenic fungi B. dermatitidis, C. immitis, H. capsulatum varieties capsulatum, duboisii, and farciminosum, and P. brasiliensis are no longer considered presumptive evidence but are considered definitive data for species identification. Technical problems associated with poor sensitivity and false-positives in some of the early tests have been resolved. The test expands the diagnostic capabilities of the laboratory. We encourage the establishment of libraries of antisera for species identification and, where appropriate, for serotyping. Since the test is simple and reagents for many of the pathogens are commercially available, the test can be performed in most laboratories. As highly defined antigens are produced, more standardized and specific tests will be developed. Hybridoma technology may provide the means for producing specific antibodies without the need for highly purified antigens, which have been difficult to produce. The identification of numerous fungi could be facilitated by application of exoantigen techniques. Specific antisera should be developed to achieve this goal and to obtain antigenic data useful for elucidating taxonomic relationships. Some fungi cannot be classified on the basis of morphologic and biochemical qualities alone. Supplementary data obtained with exoantigen analyses could undoubtedly aid in resolving such problems.

Antigens, Fungal↗
PubMed1987

Partial flip angle MR imaging.

Theoretical analysis predicts that performing magnetic resonance (MR) imaging with partial (less than 90 degrees) flip angles can reduce imaging times two- to fourfold when lesions with elevated T1 values are being examined. This time savings occurs because repetition time (TR) is reduced when imaging is performed with partial flips. Partial flip MR imaging can also improve signal-to-noise ratio (S/N) in fast body imaging. For this study, analytical tools were used to predict image contrast and S/N for short TR, partial flip sequences. Experimental implementation of the short TR, partial flip sequences that analytical work had predicted would be optimal supported the analytical predictions and demonstrated their validity. Partial flip MR imaging is applicable to reducing imaging time only when the ratio of signal differences to noise exceeds threshold values in conventional MR images. Partial flip sequences can be used to advantage in MR imaging of both the head and the body, and the observed effects are predictable through theoretical analysis.

Brain↗
PubMed1987

Surface coil assembly with switchable field of view.

The authors designed and built an overlapping surface coil assembly for magnetic resonance imaging of the spine. A small and a large coil are included, and use of one can be switched to the other without need for patient repositioning. The images are not degraded, and screening studies can immediately be followed by detailed studies.

Humans↗
PubMed1987

Hemorrhagic and nonhemorrhagic brain lesions: evaluation with 0.35-T fast MR imaging.

Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.

Adolescent↗
PubMed1987

Depth-focused radio frequency coils for MR imaging.

Surface coils improve signal-to-noise ratios by the simple expedient of reducing field of view. The uniformity of response of these coils is poor, since signal reception is weighted toward the surface of the object, which generally is of least interest. Furthermore, whole-section transmitter coils excite the subject uniformly, so that weak signals are detected from far regions. A dual-coil arrangement permits avoidance of these problems by combining the nonuniform excitation and reception characteristics of two surface coils.

Equipment Design↗
PubMed1987

Two outbreaks of blastomycosis along rivers in Wisconsin. Isolation of Blastomyces dermatitidis from riverbank soil and evidence of its transmission along waterways.

Blastomycosis cannot yet be prevented or controlled, in part because the natural habitat of the causative fungus, Blastomyces dermatitidis, remains ill defined. In investigating 2 outbreaks of blastomycosis that occurred in the summer of 1985 among persons engaged in activities along rivers in contiguous central Wisconsin counties, we isolated B. dermatitidis from soil at one of the riverbanks. Blastomycosis developed in 7 (58%) of 12 residents and guests who had gathered at a pheasant farm on the Tomorrow River in early May, and in 7 (88%) of 8 boys and 1 adult who had visited a site on the Crystal River in early June. Of the 14 patients, 13 (93%) were symptomatic. Two patients visiting the sites only once became ill 23 and 78 days after exposure, respectively. We traced one outbreak to fishing from the bank of the Tomorrow River, and the other to climbing into an underground timber fort along the Crystal River. A culture of soil and organic debris from the fishing site yielded B. dermatitidis. From these and other outbreaks, and studies of endemic disease, we conclude that riverbanks can be a natural habitat of B. dermatitidis, and that the environment around waterways represents the most important site yet identified for transmission of B. dermatitidis.

Adult↗
PubMed1987

Blastomycosis in wild wolves.

Blastomycosis was fatal to a wild wolf in Minnesota, and serologic evidence of blastomycosis was found in a Wisconsin wolf. No unusual movements were detected in the Minnesota animal from October 1983 through October 1985. However, by early December 1985, this wolf was weak and debilitated, and it perished on 14 December after approaching a human residence.

Animals↗