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Biomedical subjects

R Lazar

Publications and source records attributed to R Lazar.

At least 19 recordsLinked to original sources
PubMed2005

Spectral integration in primary auditory cortex: laminar processing of afferent input, in vivo and in vitro.

Auditory cortex neurons integrate information over a broad range of sound frequencies, yet it is not known how such integration is accomplished at the cellular or systems levels. Whereas information about frequencies near a neuron's characteristic frequency is likely to be relayed to the neuron by lemniscal thalamocortical inputs from the ventral division of the medial geniculate nucleus, we recently proposed that information about frequencies spectrally distant from characteristic frequency is mainly relayed to the neuron via "horizontal" intracortical projections from neurons with spectrally-distant characteristic frequencies [J Neurophysiol 91 (2004) 2551]. Here we test this hypothesis by using current source density analysis to determine if characteristic frequency and spectrally-distant non-characteristic frequency stimuli preferentially activate thalamocortical and horizontal pathways, respectively, in rat auditory cortex. Characteristic frequency stimuli produced current source density profiles with prominent initial current sinks in layers 3 and 4--the termination zone of lemniscal inputs from medial geniculate nucleus. In contrast, stimuli three octaves below characteristic frequency produced initial current sinks mainly in the infragranular layers. Differences between current source density profiles were only apparent for initial current sinks; profiles for longer-latency current sinks evoked by characteristic frequency and non-characteristic frequency stimuli overlapped to a greater degree, likely due to shared mechanisms of intracortical processing or to longer-latency thalamocortical contributions (lemniscal and nonlemniscal). To identify current source density profiles produced by activation of lemniscal thalamocortical inputs alone, we utilized the mouse auditory thalamocortical slice preparation. Electrical stimulation of the medial geniculate nucleus in vitro produced major current sinks in cortical layers 3/4, and excitation spread horizontally from this point throughout primary auditory cortex to produce current sinks in multiple cortical layers. These data support the hypothesis that relay of thalamocortical information throughout auditory cortex via horizontal intracortical projections may be the basis of broad spectral integration in vivo.

Acoustic Stimulation↗
PubMed2004

Up for grabs--authors are a dime a dozen: the problem of multiple authors.

AIM: To outline some of the major ethical problems related to multiple authorship. METHODS: A survey of the literature, data collected over the years, regarding multiple authors, e.g., definition, contribution, ethical behavior and guidelines, and personal experience were the primary inputs. RESULTS: Despite the efforts of a number of editors' organizations, there still is a major problem in the attribution of authors' credits to those who had nothing to do with the writing. CONCLUSIONS: The solution to this problem may be found in one of two ways: strict enforcement of standards of authorship by journal editors, i.e., rejection of articles, no matter how good they may appear to be, because they violate these standards, and/or adoption of authorship standards as understood by commercial publishers.

Authorship↗
PubMed2002

Quantitative biomonitoring of PAHs using the Barnes mussel (Elliptio complanata).

The elimination rate constants (k(2)) of nine polycyclic aromatic hydrocarbons (PAHs) were examined for the freshwater mussel Elliptio complanata. The concentrations of fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[ a]anthracene, chrysene, benzo[ b]fluoranthene, and indeno[1,2,3-c,d]pyrene revealed a significant inverse relationship with time and their k(2) values ranged from 0.10 to 0.22 day(-1). The k(2) values of these significantly cleared PAHs were similar to k(2) values observed for nonmetabolized organochlorines in mussels previously reported in the literature. The inverse relationship between k(2) and K(ow) provides evidence that the nine PAHs were being passively eliminated from the mussels and that they can be used to calibrate the mussel as a quantitative biomonitor. A general expression relating elimination rate constants and chemical K(ow) is derived for hydrophobic contaminants in E. complanata. The k(2) versus log K(ow) regression equation for mussels developed herein was similar to other studies documenting the elimination of PCBs and PAHs in a number of bivalve species.

Animals↗
PubMed2001

Subject in first person--subject in third person: subject, subjectivity, and intersubjectivity.

In this article, the author traces the history of the concepts of subject, subjectivity, and intersubjectivity in different psychoanalytic theories in the last decades. She argues that the uniqueness of these concepts and their different implications were not emphasized enough. The author discusses the various implications and contexts of the concept of subject in psychoanalytic theory proper and to relate as to: (1). The need to distinguish between the concepts of subject and subjectivity; (2). The mutual interdependence of the subject and his subjectivity and the intersubjective domain (both in the development of the individual and in theoretical thought pertaining to it). Her point of departure is from the position of the subject as a free creature, the centrality of the experiencing individual, from his/her perspective--the subject in the first person. She tries to explain the paradox implicit in the experiential dimension, the place of the other as participant, as both negating and recognizing--the subject in the third person. She suggests the interdependency of the first-person experience of subjectivity on the intersubjective dimension.

Cognition↗
PubMed2000

Presentness: an intersubjective dimension of the therapeutic act.

In this article, the author discusses a mode of the therapist's presence as an important dimension within the intersubjective framework. She seeks to introduce the term presentness to denote dimensions of the therapist's explicit usage of her implicit knowledge and the role of her unformulated experiences within the therapeutic situation. The emphasis is on the power of these shared states of mutual reverie and moments of spontaneous responsiveness on the part of the therapist. The author wants to emphasize again that this term describes an important, though not exclusive, dimension of the therapeutic interaction. It does not replace such psychic functions as observation, distancing, empathy, or such modes of object-relating as transference, countertransference or projective identification. The term presentness illuminates the symmetrical dimension of the therapeutic interaction, and its contribution to the construction of "meaningfulness" for both patient and therapist.

Adult↗
PubMed1998

Repetition, repetition compulsion, motivation, interpretation.

This paper presents three different conceptualizations (interpretations) of the phenomenon of "repetition compulsion" in the various psychoanalytic schools that refers explicitly to this conception--as return to, return of (reproduction) or recreation (transcendental transformation), or as a linear, circular or spiral-like psychic movement accordingly. The paper analyzes the metapsychological assumptions of each mode of interpretation and tries to relate the psychic models underlying these conceptions to the questions of psychotherapeutic attitude and technique in the clinical situation.

Adult↗
PubMed1998

Dynamic perspectives of paradoxical intervention.

This paper describes the use of paradoxical intervention with a patient who, despite his persistent appeals for help, remained uncooperative. It endeavors to show an understanding of the patient's destructiveness as an expression of his neediness and envy, which he expresses via his repeated use of projective identification and suggests this intervention as a way out. From a dynamic perspective the paradoxical intervention encompasses two contrasting aspects: On the one hand, it rechannels the patient's destructiveness and envy in a beneficial direction. In that sense the intervention fulfills the patient's wish for an omnipotent therapist and for painless therapy, while appearing to prevent personality change. On the other hand, the intervention interferes with the continued use of projective identification, it facilitates the expression of non-destructive aggression, creates an ambiguity surrounding the question of who is in fact in control of the therapy and, finally, it possibly facilitates the creation of a potential space. In that sense the paradoxical intervention assists in achieving both the experience of separateness and the ability to use symbolization. Parallel processes are described in the therapist's countertransference.

Adult↗
PubMed1995

The familiar and the strange: the dynamics of change.

This article relates to curative factors in the therapeutic process, or, to be more precise, to the various modes of the therapist's presence as presumed factors of change. It points to factors of change that have been discussed at length in the various streams of the analytical literature, which emphasized passive attention, absorption, processing and interpretation on the analyst's part, in an atmosphere of restraint and understanding (factors such as "free floating attention," "empathy," etc.). It stresses the importance of another psychic function different in nature--"defamiliarization"--as a condition that facilitates and accompanies processes of understanding and changes in perspective in relation to a reality aesthetically mediated by every human work of art, in general, and in relation to the personal-inner reality as it is expressed in the therapeutic work of art, in particular. This term sheds light on an active, mobile, breaking away--distancing--and rebinding aspect in the psychic functioning of the therapist (and in parallel of the patient), which allows them to "see the new" in a (supposedly) very familiar emotional given. In my view, this term joins others such as "act of freedom" and "constructive listening" in deepening our understanding of the therapeutic factor. There is reference to the term "defamiliarization," or "making strange," in its natural context--its birthplace--in literary criticism, and in a different historical context--in two key articles of the thirties that related to the causes of change in therapy in a very different way.

Adult↗
PubMed1993

Oropharyngeal swallowing after stroke in the left basal ganglion/internal capsule.

One of the foci of Martin Donner's work was the neural control of swallowing. This present investigation continues that work by examining oropharyngeal swallowing in 8 patients identified with a single, small, left-basal ganglion/internal capsule infarction and 8 age-matched normal subjects. Stroke patients were assessed with a bedside clinical and radiographic swallowing assessment, and normal subjects received only the radiographic study. Results revealed disagreement between the bedside and radiographic assessments in one of the 8 stroke patients. Stroke and normal subjects differed significantly on some swallow measures on various bolus viscosities, but behaved the same as normal subjects on a number of measures. Differences in swallowing in the stroke subjects were not enough to prevent them from eating orally. The significant differences seen in the basal ganglia/internal capsule stroke subjects may result from damage to the sensorimotor pathways between the cortex and brainstem. These differences emphasize the importance of cortical input to the brainstem swallowing center in maintaining the systematic modulations characteristic of normal swallowing physiology.

Adult↗
PubMed1993

Effects of bolus volume, viscosity, and repeated swallows in nonstroke subjects and stroke patients.

This study examined the effects of bolus volume and viscosity and the variability of repeated swallows in ten stroke patients and ten age-matched nonstroke subjects. The ten stroke patients demonstrated single unilateral cortical (three subjects), subcortical (six subjects), or brainstem (one subject) infarcts on computed tomography or magnetic resonance imaging scans at three weeks post-ictus. All subjects underwent videofluoroscopic swallow studies in which seven temporal pharyngeal swallow measures were examined. Despite the dissimilarity in lesion locations, the swallow physiology in the stroke patients was relatively homogeneous, ie, no swallowing disorders severe enough to prevent oral intake. As bolus volume increased, pharyngeal delay time diminished in stroke patients, but not in nonstroke subjects. Increasing bolus volume affected three other pharyngeal swallow measures similarly in nonstroke and stroke subjects: laryngeal closure durations and cricopharyngeal (CP) opening durations increased and duration of tongue base contact to posterior pharyngeal wall decreased. On viscosity comparisons (liquid vs paste), both subject groups displayed longer duration of base of tongue contact to posterior pharyngeal wall. On paste swallows, nonstroke subjects had longer CP opening and lower swallow efficiency, whereas stroke patients did not. This study found no statistically significant learning/repetition effect for repeated swallows in either subject group, or both groups combined.

Adolescent↗
PubMed1993

The cracked container, the containing crack: chronic illness--its effect on the therapist and the therapeutic process.

In this paper, we have tried to examine the complex dynamics of the therapist's physical chronic illness. Little attention has been paid to physical non-functioning, especially during chronic illness, and its psychotherapeutic corollaries. A crucial theme is the extent of damage to the capacity to contain. It is our claim that, when sufficiently worked through, the 'cracked therapeutic container' may serve as a facilitator of better understanding and enhance empathy. The impact of chronic illness on the therapeutic setting, contract, process and language is discussed as well as some salient features of chronicity.

Adult↗
PubMed1992

Hydrophobic carriers of vanadyl ions augment the insulinomimetic actions of vanadyl ions in rat adipocytes.

A novel family of vanadyl ion (VO2+, oxidation state +4) carriers is introduced. These carriers possess C2 symmetry, utilize two hydroxamate groups as ion binding sites, and optionally possess asymmetric carbons. Binding efficiencies and hydrophobicities are regulated by the use of a modular assembly. When applied to rat adipocytes, these carriers augment the potency of vanadyl ions to stimulate glucose metabolism. The complexes shift the dose-response curve to the left. Also, the maximal effect of vanadyl ions which is in the order of 20-30% of that of insulin is shifted toward maximal (100-115%) stimulation. Among several chelators studied, the order of synergistic potency was RL-252 greater than or equal to RL-262 greater than 1367. RL-239, RL-280, and RL-261 had smaller effects, whereas RL-282 had a negligible effect. The synergistic action of RL-252 (and other chelators as well) on VO2+ was already observed at a molar ratio of 1:0.01 of VO2+ to RL-252, respectively, and maximal augmentation occurred at a molar ratio of 1:0.1. The superiority of the hydrophobic chelators relative to the hydrophilic ones, together with the low molar ratio of chelator to VO2+ to achieve maximal effect, strongly suggests that these chelators act as vanadyl ionophores. This notion was confirmed by carrier-facilitated extraction of VO2+ from water into CHCl3 with the following order of decreasing efficacy: RL-262 greater than RL-252 greater than 1367 greater than RL-261. The chelators' potentiating effect may therefore be related to facilitated transport of VO2+ ions into the cells' interiors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1992

Distinct syndromes of hemineglect.

Hemineglect was assessed in 34 patients with right-hemisphere stroke using a letter-cancellation task and a line bisection task. No significant correlation (r = .39) was found between scores on the two tests. Ten patients who showed neglect on the cancellation task but performed normally on line bisection had frontal or deep lesions. Eleven patients with posterior lesions deviated rightward on line bisection; several of these had minimal or no cancellation deficit. A nonmotor task involving judgment of a bisected line was also performed abnormally by six patients with line bisection shift, suggesting that such shift does not result from a motor response asymmetry. We propose that separable components of the neglect syndrome may be associated with damage to discrete areas of the nondominant hemisphere.

Adult↗
PubMed1992

Recent studies on retrovirus-like particles in Chinese hamster ovary cells.

Highly concentrated (4000-7000-fold) culture fluids from CHO cells were analysed for the presence of retrovirus-like activity. Concentrates containing reverse transcriptase activity were detected and further purified by sucrose density gradient centrifugation. Particles banding at 1.13-1.16 g/ml were found to contain nucleic acid sequences and structural proteins related to those found in murine and other retroviruses. Analysis of the endonuclease gene has shown no intact open reading frames. Approximately 100-300 copies of the C-type sequences were present in the genome of CHO cell lines as well as in the DNA extracted from Chinese hamster liver, indicating that these sequences are present in the germ line of the species. Concentrates were analysed for infectivity by direct inoculation and co-cultivation with a series of detector cells. No evidence of infectivity was detected by reverse transcriptase, mink cell S+L- focus assay or by electron microscopic analysis of the inoculated detector cells after at least four passages in culture.

Animals↗
PubMed1989

Dibutyryl cAMP, aminophylline, and beta-adrenergic agonists protect against pulmonary edema caused by phosgene.

Phosgene is a toxic oxidant gas that causes the adult respiratory distress syndrome in exposed workers. Phosgene exposure markedly increased lung weight gain in buffer-perfused isolated rabbit lungs (31 +/- 5 g over 60 min after phosgene vs. 7.7 +/- 1.2 in control lungs, P less than 0.01) and markedly increased the lung leak index for 125I-albumin (0.28 +/- 0.03 after phosgene vs. 0.02 +/- 0.01 in control lungs, P less than 0.01). Pretreatment with dibutyryl adenosine 3',5' -cyclic monophosphate (DBcAMP), aminophylline, or terbutaline plus isoproterenol prevented the increase in lung weight caused by phosgene (31 +/- 5 g phosgene, 11.7 +/- 2.8 DBcAMP, 7.5 +/- 2.5 aminophylline, 6.1 +/- 1 terbutaline and isoproterenol, 6.1 +/- 1.2 control + aminophylline, and 7.7 +/- 1.2 control; all treatments were P less than 0.01 vs. the untreated phosgene group and not significantly different from control lungs). Pretreatment with aminophylline prevented the increase in lung leak index for 125I-albumin (0.28 +/- 0.03 after phosgene vs. 0.06 +/- 0.02 in aminophylline-treated lungs, P less than 0.01). Posttreatment with aminophylline and terbutaline also prevented the increase in lung weight caused by phosgene. These results indicate that phosgene dramatically increases the movement of fluid and protein across the pulmonary vasculature and that treatment with DBcAMP, aminophylline, terbutaline, or isoproterenol markedly reduces the pulmonary edema caused by phosgene.

Aminophylline↗
PubMed1988

Synthetic ferrichrome analogues with growth promotion activity for Arthrobacter flavescens.

Two families of trihydroxamic acid analogues of ferrichrome were chemically synthesized and tested for biological activity with Arthrobacter flavescens. Compounds using a tertiary amine as anchor showed little activity. Several compounds using tetrahedral carbon as anchor showed activity approaching or equalling that of the natural siderophore, ferrichrome. The biological activity is discussed in relation to physical and chemical properties of the analogues.

Arthrobacter↗
PubMed1984

[Cancer mortality in smaller regions with different structures and conditions of air quality].

The study attempts a comparative evaluation of 5 Styrian regions as to their mortality rate of cancer in general as well as cancer of the respiratory system in particular. Regions were not established according to political or administrative districts; instead, communities from areas with homogeneous characteristics as to topography, climate, and air-quality were combined in regions. Among these 5 regions, 2 are industrial centers (region Voitsberg-Köflach with 31.000 inh. and Aichfeld-Murboden with 45.000 inh.), 2 have low to average air pollution (Ausseerland with 13.000 inh. and Deutschlandsberg with 13.000 inh.), 1 is a city with appr. 247.000 inh. (Graz). The disadvantage of the small number of samples was compensated for by observing each region over a period of 11 years. The results clearly demonstrate that the region Voitsberg-Köflach has a statistically significant high mortality rate both of cancer in general as well as of cancer of respiratory system in particular. The collected data provide ample ground for the assumption that environmental conditions are to a large degree responsible for the high mortality rate; this study will provide the basis for systematic investigations of its causes.

Adolescent↗