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Biomedical subjects

A Erez

Publications and source records attributed to A Erez.

14 recordsLinked to original sources
PubMed2001

Relationship of core self-evaluations to goal setting, motivation, and performance.

A newly developed personality taxonomy suggests that self-esteem, locus of control, generalized self-efficacy, and neuroticism form a broad personality trait termed core self-evaluations. The authors hypothesized that this broad trait is related to motivation and performance. To test this hypothesis, 3 studies were conducted. Study 1 showed that the 4 dispositions loaded on 1 higher order factor. Study 2 demonstrated that the higher order trait was related to task motivation and performance in a laboratory setting. Study 3 showed that the core trait was related to task activity, productivity as measured by sales volume, and the rated performance of insurance agents. Results also revealed that the core self-evaluations trait was related to goal-setting behavior. In addition, when the 4 core traits were investigated as 1 nomological network, they proved to be more consistent predictors of job behaviors than when used in isolation.

Adolescent↗
PubMed1999

Upper posterior mediastinal tumor supplied by an atrial branch of the left circumflex artery.

We report a case of a 39-year-old woman with an upper posterior mediastinal tumor. The tumor was demonstrated by echocardiography and further defined by computerized tomography and magnetic resonance imaging. The tumor was fed by a large atrial branch of the left circumflex artery. Because of its location (adjacent to large vessels), it could not be resected by surgery.

Adult↗
PubMed1997

[Acute fungal endocarditis due to Trichosporon beigelli].

We report a 59-year-old woman with acute fungal endocarditis of a prosthetic valve caused by the endogenic organism, Trichosporon beigelli. This slowly developing disease mainly effects drug addicts who use intravenous narcotics. In nonaddicts it is rare, with mortality as high as 50%. There are only sporadic reports of T. beigelli as a complication long after open heart surgery. The ongoing infection is undetected for even years after the primary infection, due to its prolonged latent phase. We present the difficulties of diagnosis, and of treating the disease with a combination of surgery and of long-term chemotherapy.

Acute Disease↗
PubMed1997

Effects of auditory/visual and lexical/non-lexical comparisons on event-related potentials in a memory-scanning task.

A late parietal positivity (P3) and behavioural measures were studied during performance of a two-item memory-scanning task. Stimuli were digits presented as memorized items in one modality (auditory or visual) while the following probe, also a digit, was presented in the same or the other modality. In a separate set of experiments, P3 and behaviour were similarly studied using only visual stimuli that were either lexical (digits) or non-lexical (novel fonts with the same contours as the digits) to which subjects assigned numerical values. Reaction times (RTs) and P3 latencies were prolonged to non-lexical compared to lexical stimuli. Although RTs were longer to auditory than to visual stimuli, P3 latencies to memorized items were prolonged in response to visually compared to auditorily presented memorized items, and were further prolonged when preceding visual probes. P3 amplitudes were smaller to auditory than to visual stimuli, and were smaller for the second memorized item when lexical/non-lexical comparisons were involved. The most striking finding was scalp distribution variations indicating changes in relative contributions of brain structures involved in processing memorized items, according to the probes that followed. These findings are compatible, in general, with a phonological memorization, but they suggest that the process is modified by memorizing the item in the same terms as the expected probe that follows.

Adult↗
PubMed1995

The effect of lead exposure on target detection and memory scanning differs.

Visual event-related potentials were measured in lead-exposed and control subjects, while they were performing a target detection as well as a memory scanning task. Blood lead and urinary delta-aminolevulinic acid (delta-ALA) were determined in samples taken on the same day. Lead exposure did not affect the memory scanning P300 latency, but it did delay the target detection P300 latency in a dose-dependent fashion. The P300 amplitude of lead-exposed subjects was significantly reduced for both tasks, but not in a dose-dependent fashion. The target detection, but not the memory scanning, P300 latency correlated with urinary delta-ALA. No correlation of P300 with age was found, even though the subjects ranged from 20 to 60 years of age. The difference in the effect of lead exposure on the target detection and memory scanning P300 adds to the evidence that the P300 for the two tasks arises from different generators. The absence of a correlation of the measured P300 latency for each task with age in the present study raises the possibility that this extensively reported observation might, in part, be due to inappropriately matched younger and older subjects. This study indicates that evaluation of subjects exposed to toxic substances can increase our basic understanding of evoked potentials, as well as providing evidence of their toxic manifestations.

Analysis of Variance↗
PubMed1994

Lexicality and modality effects on evoked potentials in a memory-scanning task.

Event-related potentials, as well as reaction times and performance accuracies, were recorded from normal young adults during the performance of a memory-scanning task, in response to the first and second items of the memorized set and to the probe. Stimuli included computer-generated digits, presented by earphones as speech (lexical auditory) or on a screen (lexical visual), meaningless voices (nonlexical auditory) with precisely the same frequency contents as the digits, or meaningless shapes with the very same colors and contours as the digits (nonlexical visual). The evoked potentials' late positivity (P3) to memorized items was earlier to auditory than to visual stimuli. P3 to memorized items and to probes was earlier to lexical than to nonlexical stimuli. P3 amplitudes to both memorized items and probes were smaller with auditory stimuli. Assuming P3 latency to reflect processing time and amplitude to reflect attentional allocation (effort) to the task-relevant stimuli, the results support phonological representations during processing in short-term memory, with nonauditory and nonlexical stimuli requiring more processing time and effort. A significant electrode x modality x lexicality interaction may suggest that stimuli of different modalities and lexicality involve variations in the relative contributions of the brain structures involved in their processing.

Adult↗
PubMed1992

Auditory event-related potentials among dyslexic and normal-reading children: 3CLT and midline comparisons.

Event-related potentials (ERP's) to verbal and non-verbal auditory stimuli were recorded from normal-reading and from dyslexic children while performing a target-detection task ("oddball" paradigm). Two methods of analysis were used: (1) Peak latency and amplitude measures of P3 recorded from 3 midline electrodes; (2) P3 apex latency, amplitude and orientation in the three-channel Lissajous' trajectory (3CLT) derived from 3 orthogonal pairs of electrodes. P3 peak amplitude was significantly attenuated in dyslexic children compared to normal-reading children and in response to verbal stimuli compared to non-verbal stimuli. P3 apex latencies were longer and apex amplitudes larger in response to non-verbal compared to verbal stimuli. The most striking finding involved P3 apex orientation, which pointed in an upward-posterior direction with a slight tilt to the left among normal readers, but with a tilt to the right in dyslexics.

Acoustic Stimulation↗
PubMed1987

Erythema nodosum in the Negev area--a survey of 50 patients.

Fifty patients in the Negev area with erythema nodosum (EN) were studied retrospectively. The clinical picture and demographic characteristics did not differ markedly from those in the literature. In contrast to most European studies but like those from Egypt, we found streptococcal pharyngitis to be the major cause of EN. Conspicuously, sarcoidosis is a rare cause of EN in the Negev. The low incidence of EN in the Negev--2 cases/100,000 people per year--as opposed to Europe--14 cases/100,000 people per year--is hardly explained by the low occurrence of sarcoidosis in Israel. Other factors, unknown at present, may account for this low incidence.

Adolescent↗
PubMed1980

Controlled destruction and temperature distributions in biological tissues subjected to monoactive electrocoagulation.

An analysis of the temperature fields developed in a biological tissue undergoing a monoactive electrical coagulating process is presented, including thermal recovery following prolonged heating. The analysis is performed for the passage of alternating current and assumes a homogeneous and isotropic tissue model which is uniformly perfused by blood at arterial temperature. Solution for the one-dimensional spherical geometry is obtained by a Laplace transform and numerical integrations. Results obtained indicate the major role which blood perfusion plays in determining the effects of the coagulating process; tissue temperatures and depth of destruction are drastically reduced as blood perfusion increases. Metabolic heat generation rate is found to have negligible effects on tissue temperatures whereas electrode thermal inertia affects temperature levels appreciably. However, electrodes employed in practice would have a low thermal inertia which might be regarded as zero for all practical purposes. It is also found that the depth of tissue destruction is almost directly proportional to the electrical power and duration of application. To avoid excessively high temperatures and charring, it would be advantageous to reduce power and increase the time of application. Results of this study should be regarded as a first approximation to the rather complex phenomena associated with electrocoagulation. They may, nevertheless, serve as preliminary guidelines to practicing surgeons applying this technique.

Blood Circulation↗
PubMed1973

Possible errors in quantitative determination of phenylalanine ammonia-lyase activity by spectrophotometric methods.

A possible error in spectrophotometric determination of cinnamate, the product of phenylalanine ammonia-lyase activity, using nonpurified protein extracts has been shown.Under optimal conditions for phenylalanine ammonia-lyase activity, with borate buffer and in the presence of alpha-keto acids, phenylpyruvate is produced and its enol tautomer-borate complex formed, strongly absorbs at 290 nanometers.

Journal Article↗
PubMed1969

Prunin identification, biological activity and quantitative change in comparison to naringenin in dormant peach buds.

Prunin (naringenin 7-glucoside), which was identified in dormant peach buds, was found to act as a growth inhibitor of wheat coleoptile elongation.Quantitative estimation on a fresh weight basis of the flavonoid in peach buds revealed a high level in late summer, a steep decrease in autumn that became more moderate during the winter, with lowest values near bud swell in spring. Two periods of reaccumulation of prunin during October and January fitted 2 periods of arrested growth of the resting bud. A negative correlation was demonstrated between prunin and naringenin levels during August through October. It is proposed that prunin might act as a precursor for naringenin that accumulates in resting buds in autumn. It is suggested that the system glucoside-aglucone-beta glucosidase might have regulatory properties in the dormant bud.

Journal Article↗