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Biomedical subjects

L Kaufman

Publications and source records attributed to L Kaufman.

At least 397 records · Page 22Linked to original sources
PubMed1981

Attribution of psychological characteristics from masked and unmasked conversations.

A specific contribution of this study was the development of a procedure for separating the semantic and physical parameters of conversation. This procedure permits testing of the hypothesis that coverbal dimensions of conversation, that is, patterns of sounds and silence, convey information to independent listeners about the psychological states of speakers engaged in conversation. The masking procedure destroyed intelligibility of the conversation, but not the sequences of sounds and silences. Listeners rated speakers on three dimensions--warmth, anxiety, and dominance--under two conditions--masked and unmasked. Significant correlations were found between the ratings under both masked and unmasked conditions and between the ratings and a number of physical parameters of speech.

Affect↗
PubMed1981

Methods for evaluation of diagnostic imaging instrumentation.

The Rose model of signal-to-noise ratios in images has been applied to diagnostic imaging instrumentation, extending it by taking into account effects due to finite spatial resolution, background effects and texture. The model leads to an understanding of the impact of the physics of the total system (object and instrument) on output contrast and signal-to-noise ratios. Principally, it leads to an understanding of the fact that nuclear images are not (by and large) statistics limited. The model can also be used to compare different imaging techniques. To the extent that the signal-to-noise ratio is a necessary but not sufficient estimator of the detectability of a lesion, the model does not provide a complete description of the imaging characteristics of an instrument.

Evaluation Studies as Topic↗
PubMed1981

Detection of antibodies and antigenemia in leukemic patients with candidiasis by enzyme-linked immunosorbent assay.

Standard tests and two enzyme-linked immunosorbent assays (ELISAs) were compared for detecting systemic candidiasis in 92 leukemic patients. Antibodies to Candida were detected by immunodiffusion (ID), latex agglutination (LA), and indirect ELISA; antigenemia was evaluated by indirect ELISA inhibition. In 48 patients without candidiasis (group 1), sera from 27% reacted in ID and 13% in LA tests; titers of antibody by ELISA occurred in all patients. In 34 patients without disseminated candidiasis (groups 2 and 3), Candida species were isolated; sera from 35% and 32% were positive in the ID and the LA test, respectively. In nine of 10 patients with disseminated candidiasis (group 4), LA and ID tests were negative. Seven patients in groups 1-3 without disseminated candidiasis were antigenemic (false-positive rate, 9%). Antigenemia was detected in seven of 10 patients with disseminated candidiasis; in the remaining three patients sera were drawn too early to be of diagnostic value. Thus, monitoring of immunosuppressed patients for mannan antigenemia is useful for the detection of disseminated candidiasis.

Adult↗
PubMed1981

Comparative evaluation of the Iatron serological Candida check kit and the API 20C kit for identification of medically important Candida species.

A newly developed commercial serological test (Iatron Laboratories, Inc., Tokyo, Japan) for the rapid identification of medically important species of Candida was evaluated against the API 20C (Analytab Products, Plainview, N.Y.) and the standard Wickerham assimilation and fermentation procedures. Our results indicated that the Iatron and the API 20C methods are 95% accurate since both permitted identification of 78 of 82 Candida isolates, representing eight medically important species. None of the tests on nine Cryptococcus, six Trichosporon, three Geotrichum, three Saccharomyces, and one Rhodotorula species yielded false-positive reactions. False-positive serological tests occurred with a species of Pichia and Candida rugosa. The API 20C procedure correctly identified C. rugosa but not the Pichia sp. The Iatron method permitted reliable identification of the Candida species in 10 min to 5 h, whereas the API 20C procedure required 48 to 72 h. Neither method could properly identify sucrose-negative Candida tropicalis or Candida lusitaniae isolates. In addition, Candida albicans isolates could be serotyped by the Iatron method.

Agglutination Tests↗
PubMed1981

Nuclear magnetic resonance imaging of the abnormal live rat and correlations with tissue characteristics.

Nuclear magnetic resonance (NMR) images of live rats with sterile and pyogenic abscesses, hematomas, and various implanted and spontaneous neoplasms demonstrated good contrast differentiation between pathologic and surrounding normal tissues. This differentiation was maximal when both the T1 and T2 tissue relaxation times were used as criteria. Neoplasms have a broad range of T1 and T2 values and may be confused with abscesses or hematomas. Tissue rate constants (1/T1 and 1/T2) are mainly dependent on total water content, the exception being fat, which has a 1/T2 value much shorter than that expected on the basis of water content alone.

Abscess↗
PubMed1981

Validation through self and other ratings on dimensions of six nonstressful multi-scaled personality instruments.

Six nonstressful personality instruments were concurrently validated using respondent and close friend ratings on specific scale dimensions. Tests were administered to 203 predominantly Caucasian college students. Prior to testing, the individual and a close friend through self-ratings and ratings of the respondents had estimated the strengths of the tested personality Variables on a seven-point scale. The definitions of the various personality dimensions were taken from publisher's manuals. An estimated whole test validity was obtained by an average of the individual scale validities using a conversion of Pearson's r to z'. Significant differences among and between subtest validities were found by ANOVA. All "self-rating" validities were significant (.001), with two of these self-rating validities significantly different (.01) than the other four tests. Only two "other-rating" validities were significant. All six tests appeared to be valid for college population use From preliminary analysis, counselees could rate themselves accurately on most test measures. In some cases self-ratings might be used in lieu of giving the test.

Journal Article↗
PubMed1981

Potential hazards in NMR imaging: heating effects of changing magnetic fields and RF fields on small metallic implants.

To test if changing magnetic fields and radiofrequency fields used in nuclear magnetic resonance imagers could induce electrical currents capable of causing localized tissue heating in metal surgical clips and prostheses, steel surgical clips, copper wire clips, and hip prostheses were exposed to fields greater than those used in the nuclear magnetic resonance imager. Observations indicated that no significant heating should be expected from implanted surgical clips during exposure. The heating of larger metallic implants should be further investigated.

Hot Temperature↗
PubMed1981

On the relation between somatic evoked potentials and fields.

Recently Okada et al. (1981) reported that stimulation of the median nerve with a brief electrical impulse at the wrist evoked a transient change in the brain's magnetic field. This somatic evoked field (SEF) is similar in its temporal waveform to the response to the same stimulus reported for the electrical potential recorded on the pial surface of the exposed brain. Moreover, both measures differ substantially from the somatic evoked potential (SEP) recorded at the scalp. The present paper describes a more detailed account of the SEF as well as an analysis of its relation to the SEP and to the somatic pial response (SPR). Its purpose of the use the three measures in clarifying our understanding of the nature and locations of sources of the SEF. This paper is divided into three sections. The first is a background section which reviews basic principles and models that are widely used in deducing the locations of sources of evoked potentials and fields. It indicates the types of currents which may give rise to the SEF, and distinguishes between them and the current which is associated with the SEP. It concludes with a rationale for the experiments described in the next section. The experiments described in the second section determined how the SEF varies with the position from which it is recorded at the scalp. These variations turn out to be essential to our understanding of the nature and location of the sources of the SEF. The third section summarizes the results of the experiments and makes clear how they affect theories of the origin of the SEF. The findings also have implications for our understanding of the SEP and SPR. The most salient findings are: (1) The SEF recorded normal to the head provides essentially the same information as that provided by reported potential recordings from the exposed surface of the brain (the SPR). (2) The SEF originates in the cortex of the cerebrum in the vicinity of the central sulcus. (3) The currents that account for identifiable components of the SEF are opposite in direction to those that account for corresponding components of the SPR. This result is consistent with models that ascribe the detected field normal to the scalp to intracellular currents, whereas the VEP is associated with extracellular currents flowing in the opposite direction.

Brain↗
PubMed1981

Quantitative characterization of signal-to-noise ratios in diagnostic imaging instrumentation.

Different imaging modalities can operate on basically different object (biologic) parameters. In addition to an understanding of the intrinsic differences among modalities, it is useful to also understand how these differences translate into information on the output image. Thus, given a defined diagnostic situation, it is important to estimate the confidence (or signal-to-noise level) with which a particular abnormality is observed. For this purpose, we have extended the Rose model for characterization of signal to noise in images by taking into account the sources of degradation of contrast found in diagnostic imaging instrumentation. The model is not only useful in comparing different instruments applied to the identical physiologic state, but can also be used to compare signal to noise in images resulting from different instruments imaging the same subject under different conditions (for instance, positron and planar imaging in the head). The model can also be formulated so as to compare the signal to noise in images obtained from the same object by totally different modalities. A particularly useful feature of this model is its ability to yield an understanding of the intrinsic limitations of any one modality.

Brain↗
PubMed1981

Nuclear magnetic resonance imaging.

NMR imaging is based on the ability to induce and monitor resonance of the magnetic moment of nuclei with an odd number of protons and/or neutrons in the presence of magnetic fields. By the use of magnetic fields whose strength varies with position, it is possible to define both the location and concentration of resonant nuclei, and, thereby, to create images that reflect their distribution in tissue. Hydrogen because it is the most sensitive of the stable nuclei to NMR and because it is also the most abundant nucleus in the body, is ideally suited for NMR imaging.

Animals↗
PubMed1981

Use of human mammary epithelial antigens (HME-Ags) in breast cancer diagnosis.

The use of human mammary epithelial antigens (HME-Ags) was explored in detection of human breast cancers. Specific antibodies were made against HME-Ags, which are normal differentiation antigens of human breast epithelium, and were used in a solid phase radioimmunoassay. Circulating HME-Ags were detected in sera of breast cancer patients with high-tumor load. These antibodies, after radioiodination, were also successfully used to localize human breast tumors grafted in athymic nude mice by whole body radioimaging devices. These results suggest that HME-Ags can be applied to breast cancer diagnosis with higher specificity than those already reported.

Animals↗
PubMed1980

Related effects of calcium and serum on the G1 phase of the human W138 fibroblast.

Deprivation of extracellular Ca or serum inhibits the proliferation of WI38 human diploid fibroblasts. Under these conditions, the cells become quiescent at a point in the cell cycle typical of early G1 or G0 phase-arrested cells. Exit of the cells from this point in the cycle appears to require both the presence of serum and Ca simultaneously. If quiescent cells are serum-stimulated in low Ca medium (0.01 mM), they do not progress through G1 to the S phase, which normally requires 14-18 hr. However, they remain competent to do so. Addition of Ca for up to 48 hr after serum stimulation results in an equal fraction of the cells progressing G1 phase as compared to the presence of Ca at the time of serum addition. In contrast, if quiescent cells are serum-stimulated in the presence of Ca, which is then removed, the cells can remain competent to enter S phase for only 10-12 hr. Re-addition of Ca beyond this time does not allow G1 progression on a normal schedule. These data suggest that Ca and serum are both required to trigger, in whole or in part, the pleiotypic response. Ca appears also to render the cells competent to enter S phase, but this competence is labile; an observation consistent with the PDGF-induced competence observed previously in the 3T3 cell. These observations are in contrast to previous data from other cell types which suggest that Ca is required only in late G1 phase for successful entrance to S phase.

Calcium↗
PubMed1980

Petriellidium boydii infection of the sphenoid sinus.

Petriellidium boydii infection of the sphenoid sinus in a previously healthy woman was initially diagnosed by immunofluorescent staining of biopsy tissue sections. The diagnosis was confirmed by demonstrating P. boydii precipitins in serum and by isolating the infecting fungus. Despite surgical drainage and intensive therapy with miconazole nitrate, the outcome, because of intracranial extension, was fatal.

Ascomycota↗
PubMed1980

Communicating hydrocephalus caused by Aspergillus flavus.

A patient with a past history of sporadic parenteral drug abuse had communicating hydrocephalus associated with arachnoiditis over the lumbar spinal cord. The diagnosis of aspergillosis was made by a newly described immunofluorescent staining procedure and was later confirmed by culture. The spectrum of central nervous system aspergillosis associated with drug abuse is reviewed.

Adult↗