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Z Segal

Publications and source records attributed to Z Segal.

13 recordsLinked to original sources
PubMed2004

Limbic-frontal circuitry in major depression: a path modeling metanalysis.

This paper reports the results of an across lab metanalysis of effective connectivity in major depression (MDD). Using FDG PET data and Structural Equation Modeling, a formal depression model was created to explicitly test current theories of limbic-cortical dysfunction in MDD and to characterize at the path level potential sources of baseline variability reported in this patient population. A 7-region model consisting of lateral prefrontal cortex (latF9), anterior thalamus (aTh), anterior cingulate (Cg24), subgenual cingulate (Cg25), orbital frontal cortex (OF11), hippocampus (Hc), and medial frontal cortex (mF10) was tested in scans of 119 depressed patients and 42 healthy control subjects acquired during three separate studies at two different institutions. A single model, based on previous theory and supported by anatomical connectivity literature, was stable for the three groups of depressed patients. Within the context of this model, path differences among groups as a function of treatment response characteristics were also identified. First, limbic-cortical connections (latF9-Cg25-OF11-Hc) differentiated drug treatment responders from nonresponders. Second, nonresponders showed additional abnormalities in limbic-subcortical pathways (aTh-Cg24-Cg25-OF11-Hc). Lastly, more limited limbic-cortical (Hc-latF9) and cortical-cortical (OF11-mF10) path differences differentiated responders to cognitive behavioral therapy (CBT) from responders to pharmacotherapy. We conclude that the creation of such models is a first step toward full characterization of the depression phenotype at the neural systems level, with implications for the future development of brain-based algorithms to determine optimal treatment selection for individual patients.

Algorithms↗
PubMed2000

The frequency of Candida parapsilosis in onychomycosis. An epidemiological survey in Israel.

Candida albicans is regarded as the major pathogen in yeast-induced onychomycosis. Based on our impression of an increasing prevalence of Candida parapsilosis in this disease, we examined the data of two mycology laboratories in the same geographic location, from 1994 to 1996 in one (centre A) and for 1995 (6 months) in the other (centre B). A total of 954 and 230 toenails and 621 and 190 fingernails, respectively, underwent KOH microscopy and culture studies in each centre. Positive findings were noted in 45 and 65% of the toenails and 44 and 72% of the fingernails, respectively. In the toenails, Candida spp. were found in 22 and 15%, respectively, and in the fingernails, in 77 and 63%, respectively. The most frequent Candida species was C. parapsilosis (39.5% in toenails, 36.7% in fingernails), followed by C. albicans (19.5% in toenails, and 34.4% in fingernails). These results demonstrate a higher frequency of isolation of C. parapsilosis compared with C. albicans in onychomycosis. This might have important therapeutic implications.

Candida↗
PubMed1998

Memory and long-term potentiation (LTP) dissociated: normal spatial memory despite CA1 LTP elimination with Kv1.4 antisense.

Long-term potentiation (LTP) in the hippocampal slice preparation has been proposed as an in vitro model for long-term memory. However, correlation of LTP with memory in living animals has been difficult to demonstrate. Furthermore, in the last few years evidence has accumulated that dissociate the two. Because potassium channels might determine the weight of synapses in networks, we studied the role of Kv1.4, a presynaptic A-type voltage-dependent K+ channel, in both memory and LTP. Reverse transcription-PCR and Western blot analysis with specific antibodies showed that antisense oligodeoxyribonucleotide to Kv1.4 microinjected intraventricularly into rat brains obstructed hippocampal Kv1.4 mRNA, "knocking down" the protein in the hippocampus. This antisense knockdown had no effect on rat spatial maze learning, memory, or exploratory behavior, but eliminated both early- and late-phase LTP and reduced paired-pulse facilitation (a presynaptic effect) in CA1 pyramidal neurons without affecting dentate gyrus LTP. This presynaptic Kv1.4 knockdown together with previous postsynaptic Kv1.1 knockdown demonstrates that CA1 LTP is neither necessary nor sufficient for rat spatial memory.

Animals↗
PubMed1996

Change in thyroid hormone levels following response to cognitive therapy for major depression.

OBJECTIVE: Various somatic antidepressant treatments of depression are associated with substantial but limited decreases in T4 levels. This study examined changes in patients' thyroid hormone levels during a period of cognitive behavior therapy. METHOD: Thyroid hormone levels of 30 patients with major depressive disorder were measured before and after they received 20 weekly sessions of cognitive behavior therapy. RESULTS: There were significant decreases in measures of T4 in the 17 responders to cognitive behavior therapy and increases in the 13 nonresponders. CONCLUSIONS: Cognitive behavior therapy has an effect on the thyroid axis similar to that of somatic antidepressant treatments.

Adult↗
PubMed1995

How does cognitive therapy prevent depressive relapse and why should attentional control (mindfulness) training help?

There is encouraging evidence that structured psychological treatments for depression, in particular cognitive therapy, can reduce subsequent relapse after the period of initial treatment has been completed. However, there is a continuing need for prophylactic psychological approaches that can be administered to recovered patients in euthymic mood. An information-processing analysis of depressive maintenance and relapse is used to define the requirements for effective prevention, and to propose mechanisms through which cognitive therapy achieves its prophylactic effects. This analysis suggests that similar effects can be achieved using techniques of stress-reduction based on the skills of attentional control taught in mindfulness meditation. An information-processing analysis is presented of mindfulness and mindlessness, and of their relevance to preventing depressive relapse. This analysis provides the basis for the development of Attentional Control Training, a new approach to preventing relapse that integrates features of cognitive therapy and mindfulness training and is applicable to recovered depressed patients.

Aftercare↗
PubMed1995

Dependency, self-criticism and attributional style: a reexamination.

The relationship between dependency and self-criticism personality dimensions, as measured by the Depressive Experiences Questionnaire (DEQ), and attributions to content-specific (affiliative, achievement) hypothetical outcome domains on the Expanded Attributional Style Questionnaire (EASQ) was examined. Dependency did not correlate with either affiliative or achievement domains, whereas self-criticism correlated with both. Replicating previous findings there was also no evidence of differential causal assignment across the attributional dimensions. These results add to an accumulating literature suggesting that the DEQ might not be measuring two independent personality types.

Achievement↗
PubMed1982

Lithium and electrolytes plasma/RBC ratio and paradoxical lithium neurotoxicity.

1. Although lithium neurotoxicity and EEG disturbances are known to be associated with toxic plasma lithium levels, it may also be paradoxically manifested when plasma lithium levels are within the therapeutic range. 2. Plasma and RBC lithium and electrolytes levels were measured in 50 patients with affective disorders during the course of lithium therapy. Seventeen of them suffered from lithium neurotoxicity. 3. It is suggested that in the course of lithium treatment, in the manic and depressed phases as well as during prophylaxis, lithium ratio is a better correlate of lithium neurotoxicity than plasma lithium alone, even when the plasma lithium levels are within the therapeutic range. 4. In addition, an increase in the intra-erythrocyte sodium/potassium ratio was observed in toxic patients in comparison to non-toxic patients.

Adult↗
PubMed1980

The effect of alcohol and placebo on affective reactions of social drinkers to a procedure designed to induce depressive affect anxiety and hostility.

Randomly assigned 33 males to one of three alcohol conditions: High dose (two groups), placebo, and no-dose. All Ss after drinking performed a pseudo test of intelligence. One group of high-dose Ss received feedback that indicated an extremely good performance on the intelligence task (Incentive Gain), while all other Ss received extremely poor performance scores (Incentive Loss). Analysis of pre-post feedback scores on the Multiple Affect Adjective Check List indicated differential effect of alcohol and placebo with no change of depressive affect in the two high-dose alcohol groups, but an increase in placebo Ss. Furthermore, incentive loss high-dose Ss rated themselves as significantly more intoxicated than did incentive gain high-dose Ss. The results are discussed in terms of attribution for success and failure, cognitions and depressive affect, and tension reduction models of alcoholism.

Adolescent↗
PubMed1979

Antipsychotic effect of propranolol on chronic schizophrenics: study of a gradual treatment regimen.

Ten chronic treatment-resistant schizophrenic patients were treated in a single-blind trial for six weeks with propranolol in daily doses increasing up to 3 g in order to evaluate a modified dose regimen of propranolol treatment in these patients. Four of the patients improved significantly and could be released from the hospital, regaining premorbid social and work adjustments. The modified regimen proved safe as long as the dose increment was not more than 80 mg/day. The mean therapeutic level of propranolol was 1600 mg/day, which proved to be a safe dose. Although three patients with hypertensive encephalophaty responded, their response was related not to the maximum dose but to a drastic change in the rate of the dose increase. It seems that on the basis of these results a double-blind comparative study would be worthwhile.

Adolescent↗
PubMed1978

Negative expectancy as a mediating variable in marihuana intoxication.

Sixty experienced marihuana smokers participated in a study designed to assess the effect of a negative expectancy on marihuana intoxication. Two different environments, threat of shock and no-threat, were used under the drug conditions of marihuana and placebo. Ss came into the laboratory and adjusted a level of shock received at their fingertips, to a point of mild discomfort. Only those Ss in the threat groups were given the expectation that they would receive the shock at random times during the sessions. Results show that Ss in the marihuana threat group got subjectively less intoxicated, found the environment less pleasant, and yet had higher pulse rates than did Ss in the marihuana no-threat group. The results are discussed in terms of a cognitive component, and specifically that of labelling, in the determination of level of intoxication.

Adolescent↗