Biomedical subjects

S E Mason

Publications and source records attributed to S E Mason.

At least 19 recordsLinked to original sources

PubMed1994

Maintenance imipramine therapy for secondary depression in schizophrenia. A controlled trial.

BACKGROUND: Although recent studies have documented the benefit of adjunctive antidepressant medication for the short-term treatment of certain patients with operationally defined syndromes of postpsychotic depression, the value of maintenance adjunctive antidepressant treatment in this circumstance has not been properly established. METHODS: This study examined 24 schizophrenic or schizoaffective patients with postpsychotic depression or negative symptoms. These patients had all been benefited over the short term by the addition of adjunctive imipramine hydrochloride to their ongoing fluphenazine decanoate/benztropine mesylate regimens, and this adjunctive treatment had been successfully continued for 6 months. In a randomized double-blind protocol, treatment with adjunctive imipramine hydrochloride (mean, 233 +/- 72 mg/d) was then either maintained or tapered to placebo for an ensuing 1-year trial, while treatment with fluphenazine and benztropine continued. RESULTS: Significantly more patients who received placebo substitution relapsed into depression (P < .001). Patients who received placebo substitution were also more likely to experience relapses into psychosis (P < .02). CONCLUSIONS: These results support the clinical value of maintenance adjunctive imipramine therapy among initially responsive patients with postpsychotic depressions.

Adult↗

PubMed1992

Correlation between the induction of an immediate early gene, zif/268, and long-term potentiation in the dentate gyrus.

Expression of the immediate early gene zif/268 (also termed NGFI-A, Krox 24, TIS8 and Egr-1) was investigated in awake rats following various long-term potentiation (LTP) induction protocols. zif/268 mRNA (Northern blots) and protein (immunohistochemistry) levels sharply increased following LTP, and followed a time course characteristic of other immediate early genes. When measured across 3 tetanization protocols known to produce differing degrees of LTP persistence, zif/268 induction was found to be more highly correlated with LTP duration than with the magnitude of initial LTP. These data support the hypothesis that the immediate early gene zif/268 plays a role as a third messenger in the cascade of cellular and nuclear events that govern the persistence of LTP.

Animals↗

PubMed1992

Adjunctive imipramine for dysphoric schizophrenic patients with past histories of cannabis abuse.

1. Twenty-one schizophrenic or schizoaffective patients with histories of cannabis abuse and operationally-defined syndromes of post-psychotic depression completed a double-blind trial of adjunctive imipramine added to their on-going medication regimen of fluphenazine decanoate and benztropine. 2. The imipramine-treated patients had superior global outcome. 3. Subscales suggested that specific improvement occurred in imipramine-treated patients in the domain of depression-like features. 4. Psychotic symptomatology was not found to be exacerbated by the imipramine.

Adolescent↗

PubMed1992

The 10-year experience of an academically affiliated occupational and environmental medicine clinic.

Occupational and environmental diseases are underrecognized. Among the barriers to the successful diagnosis, treatment, and prevention of these conditions are inadequate consultative and information resources. We describe the 10-year clinical and training experiences of an academically affiliated referral center that has as its primary goal the identification of work-related and other environmental diseases. The University of Washington Occupational and Environmental Medicine Program has evaluated 6,048 patients in its diagnostic and screening clinics. Among the 2,841 seen in the diagnostic clinics, 1,553 (55%) had a work-related condition. The most prevalent diagnoses included asbestos-related lung disease (n = 603), toxic encephalopathy (n = 160), asthma (n = 119), other specific respiratory conditions (n = 197), carpal tunnel syndrome (n = 86), and dermatitis (n = 82). The clinics serve as a training site for fellows in the specialty training program, primary care internal medicine residents, residents from other medical specialties, and students in industrial hygiene, toxicology, and occupational health nursing. The program serves two additional important functions: providing consultative services to community physicians and training specialists and other physicians in this underserved area of medicine.

Adolescent↗

PubMed1992

Continuation treatment with adjunctive imipramine in schizophrenia.

An open continuation treatment trial was undertaken for schizophrenic and schizoaffective patients with postpsychotic depressions who had manifested favorable responses to initial treatment with adjunctive imipramine added to their fluphenazine decanoate and benztropine regimen. Of 27 patients enrolled, none had a psychotic or depressive relapse, and 23 completed the 6-month study. The patients did well; completers' Global Assessment Scale scores improved with statistical significance during the trial. Side effects also appeared to improve during the trial. The results therefore support continuation treatment with adjunctive antidepressant medication for those patients with postpsychotic depressions who initially respond favorably to this regimen.

Adult↗

PubMed1991

Antidepressant for substance-abusing schizophrenic patients: a minireview.

1. Substance abuse and post-psychotic depression are both frequently encountered concomitants of schizophrenia. 2. Substance abuse may be associated with depression-like symptomatology in the course of schizophrenia, and patients may attempt to self-medicate these symptoms with substances of abuse. 3. Antidepressant medication has been found to be a useful adjunct to treatment in at least some cases of substance abuse and some cases of post-psychotic depression. 4. Preliminary evidence exists suggesting that adjunctive antidepressant medication, added to a neuroleptic, may be useful for at least some stable dysphoric substance-abusing schizophrenic patients. 5. It is important to attempt to rule out even subtle neuroleptic-induced akinesia in such patients with a vigorous trial of antiparkinsonian medication.

Antidepressive Agents↗

PubMed1991

The use of antidepressants for negative symptoms in a subset of schizophrenic patients.

The authors used a randomized, placebo-controlled design to assess the therapeutic efficacy of adjunctive imipramine, added to fluphenazine decanoate and benztropine, among well-stabilized, negative-symptom schizophrenia and schizoaffective disorder patients who additionally met operationalized criteria for postpsychotic depression. The outcome of the imipramine-treated group was superior in both global ratings and a specific negative-symptom scale. Exacerbation of psychotic symptomatology was not found to be problematic. The implications of this study are discussed in terms of a potential strategy for pharmacotherapy among certain negative-symptom patients and in terms of its relevance to a possible pathophysiological basis for the negative-symptom state.

Adult↗

PubMed1990

Effects of the NMDA antagonists CPP and MK-801 on radial arm maze performance in rats.

The dose- and time-dependent effects of N-methyl-D-aspartate receptor/channel antagonists on radial 8-arm maze performance were examined in rats. Both CPP (1.0-30 mg/kg), a competitive NMDA antagonist, and MK-801 (0.1-1.0 mg/kg), a noncompetitive NMDA antagonist, produced dose-dependent increases in the number of errors made to sample all 8 baited arms. The effective doses of both drugs produced maximal performance impairments 2 hr after IP injection, and no effects after 24 hr. In a second radial arm maze task where only 4 arms were baited, CPP (10 mg/kg) had a somewhat greater effect on the number of working memory errors than on reference memory errors. MK-801 (0.1, 0.33 mg/kg) had no effects on either this task or on a task involving a 1-hr delay between correct choices 4 and 5 on the 8 choice task. CPP (10 mg/kg), however, impaired performance on this latter task. These results indicate that doses of NMDA antagonists, sufficient to block hippocampal long-term potentiation, also disrupt radial arm maze performance.

Animals↗

PubMed1990

Induction of Fos-like immunoreactivity and the maintenance of long-term potentiation in the dentate gyrus of unanesthetized rats.

Memory formation in the mammalian central nervous system may require long-lasting alterations in gene expression. However, it is not yet known whether the candidate memory mechanism long-term potentiation (LTP) requires alterations in gene expression for its maintenance, nor the extent to which the time course of LTP can be manipulated at the time of induction. In this study we influenced the time course of LTP decay for the perforant path input to the dentate gyrus in awake rats by manipulating conditions at the time of induction, and correlated the outcome with the induction of c-fos protein(s) (Fos), as measured immunohistochemically in the dentate gyrus of separate animals 2 h post-tetanization. Sodium pentobarbital, which blocks the induction of Fos-like immunoreactivity (Fos-IR), also blocked a long-duration form of LTP maintained over weeks. On the other hand, two different patterns of delivery of 50 trains, that produced similar time courses of LTP decay, produced markedly different degrees of Fos-IR induction. In addition, while stimulation consisting of only 10 trains induced a sizable Fos response, it only produced LTP lasting a few days. When the 10-train stimulation was repeated on 3 or 5 consecutive days, there appeared to be no additional Fos-IR induction, yet the LTP decay time constant was considerably prolonged. Thus there is little correlation between the degree of Fos-IR induction and the subsequent durability of LTP.

Animals↗

PubMed1990

Patients' and caregivers' adaptation to improvement in schizophrenia.

Treatment of poorly functioning schizophrenic patients with antidepressant medication may lead to a relatively rapid increase in their level of activity, autonomy, and assertiveness. Caregivers who had been accustomed to the patients' more blunted affect and docile behavior may perceive this change as an increase in hostility. Patients who do not know how to express anger and other strong feelings appropriately may also find changes in their level of assertiveness to be stressful. The authors illustrate these problems with case examples and suggest that psychoeducation, regular contact with the treatment team, and training in communication can help both patients and caregivers adjust to the patients' improved condition.

Adult↗

PubMed1990

Adjunctive imipramine maintenance in post-psychotic depression/negative symptoms.

Fourteen schizophrenic or schizoaffective patients, who had had operationalized syndromes of post psychotic depression or negative symptoms unresponsive to adjunctive benztropine but responsive to adjunctive imipramine, completed a double-blind maintenance treatment trial of adjunctive imipramine vs. placebo. All patients were maintained on standing doses of fluphenazine decanoate and benztropine throughout. All six patients tapered to placebo relapsed into their depression-like, negative symptom state, whereas only 2 of 8 patients maintained on imipramine had such a course (p = .009, favoring imipramine maintenance). No patients maintained on imipramine relapsed into psychosis. These results suggest the advisability of maintaining adjunctive imipramine treatment, in conjunction with appropriate neuroleptic and antiparkinsonian regimens, in stable, syndromally defined, postpsychotic depressed or negative symptom patients initially responsive to adjunctive imipramine.

Adult↗

PubMed1989

Long-term potentiation and the induction of c-fos mRNA and proteins in the dentate gyrus of unanesthetized rats.

We tested the hypothesis that the nuclear proto-oncogene c-fos is involved in long-term potentiation (LTP) of the perforant path-dentate gyrus synapse in awake freely moving rats. High-frequency stimulation that produced LTP induced c-fos mRNA and protein in the dentate granule cells but not in CA1, CA3, or the entorhinal cortex. However, the degree of LTP induction did not correlate with the degree of c-fos induction. Agents that interfered with the production of LTP (e.g. NMDA antagonists) also prevented c-fos induction. Low-frequency stimulation did not lead to either LTP or c-fos induction. However, c-fos induction did not necessarily follow LTP production because some high-frequency stimulation protocols that produced good LTP did not lead to c-fos induction. Thus, c-fos induction is clearly not related to LTP production in unanaesthetized rats, but it remains to be determined if it plays some role in LTP maintenance.

Adaptation, Physiological↗

PubMed1988

Effects of the NMDA receptor/channel antagonists CPP and MK801 on hippocampal field potentials and long-term potentiation in anesthetized rats.

The effects of the competitive and non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, 3-[(+/- )-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (CPP) and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5,10-imine maleate (MK801) were tested on hippocampal field potentials and long-term potentiation (LTP) in urethane-anesthetized rats. Neither drug had any significant effects on the dentate hilar population excitatory postsynaptic potential (EPSP) evoked by perforant path stimulation 30 or 150 min postinjection. However, both drugs produced a dose-dependent decrease in population spike amplitude at these times. Both drugs (at the highest doses) also blocked LTP when induced 150 min after administration, and this was related to a smaller response evoked during tetanization. CPP exerted similar effects on commissural-CA1 evoked responses and LTP. CPP remained an effective blocker of LTP for 6-8 h, and was still partially effective after 20-24 h. MK801 washed out more rapidly. The effect of MK801 on LTP did not depend on stimulus-evoked transmitter release during the pretetanization period. The results indicate that both CPP and MK801 have potent effects on LTP in the in vivo preparation, but that this is accompanied by an independent effect on evoked cell discharge.

Action Potentials↗

PubMed1988

Total lung capacity. An insensitive measure of impairment in patients with asbestosis and chronic obstructive pulmonary disease?

The total lung capacity (TLC) is frequently used as a measure of respiratory impairment in patients with asbestosis. Because asbestosis and chronic obstructive pulmonary disease (COPD) exert opposite effects on the TLC, it may be an insensitive measure of impairment in patients with both abnormalities. To assess this, we compared asbestos-exposed patients with functional evidence of COPD and radiographic evidence of interstitial fibrosis (group 1) to those with interstitial fibrosis alone (group 2). Despite the two groups being comparable in degree of radiographic "fibrosis," no case of restrictive impairment (reduced TLC) was identified among those with both interstitial fibrosis and COPD (group 1), compared to 33 percent of those with interstitial fibrosis alone (group 2). In addition, those patients with both interstitial fibrosis and COPD, compared to those with interstitial fibrosis alone, were found to have greater impairment as measured by alveolar-arterial oxygen difference and diffusing capacity. We conclude that the TLC is an insensitive measure of impairment due to asbestosis in patients with the common setting of coexistent asbestosis and COPD.

Aged↗

PubMed1987

Kindling-induced changes in the EEG recorded during stimulation from the site of stimulation. II. Comparison between spontaneous and evoked potentials.

We previously described how the EEG activity recorded during kindling-inducing tetanic stimulation, from the site of stimulation, consists of three major components. Here, we investigate the nature and role of component 1, an initial evoked potential, seen at the beginning of tetanus, and we compare it with the potential evoked by single-pulse stimulation and with the spontaneous interictal discharges seen after kindling in both the amygdala and hippocampus. The amplitude of component 1 increased during kindling, and the waveform, latency, and stimulus-response curve of component 1 were all similar to those of potentials evoked by single-pulse stimulation. Furthermore, in acute experiments, in which the amygdala was kindled by tetanic stimulation at 1-h intervals, the evoked potentials in the amygdala and pyriform cortex were markedly potentiated, whereas no obvious potential was recorded at the same latency from the ventral or dorsal hippocampus, subiculum, nor the prepyriform region. Thus, we conclude that, in the case of amygdala kindling, the nature of component 1 is a local direct and monosynaptic response involving the amygdala and pyriform cortex, and that the increased amplitude of component 1 after kindling may be related to long-term potentiation. Although the single-pulse stimulation produced late burst-like components in the amygdala and hippocampus after kindling, it produced neither EEG suppression, well-formed rhythmic synchronous bursts, nor epileptiform discharge, suggesting that component 1 alone is not sufficient for the subsequent events that may be essential to the seizure-triggering mechanism.

Amygdala↗

PubMed1986

Age and gender as factors in facial recognition and identification.

The present study was designed to test adult age differences in the recognition and identification of faces. Young and old women were shown slides of faces paired with common first names. Their task was to associate the names and faces for a subsequent recognition test. On the test, subjects were shown a larger set of faces and they were asked to indicate which of the faces had been presented earlier. For those faces judged to be familiar, subjects were asked to select, from two alternatives, the name which was originally paired with the face. It was hypothesized that people would remember faces most like their own and, as predicted, young subjects tended to make fewer errors with young faces and old subjects tended to make fewer errors with old faces.

Adolescent↗

PubMed1986

Need for cognition related to time perception.

Undergraduates who scored high on need for cognition tended to underestimate a 90-sec. filled interval and their number of correct single solution anagrams tended to correlate negatively with estimated time. Subjects high in need for cognition reported the task was easy but enjoyment and prior experience were similar.

Adult↗

PubMed1985

Adult age differences in visual search.

The visual search technique was used to assess adult age differences in visual information extraction. The study included three adult age groups. In Experiment 1, participants searched for targets embedded in a list of unrelated words. Targets were defined structurally, phonemically, or semantically. Search for structural targets was faster than search for phonemic and semantic targets. This was true for all three age groups. In Experiment 2, targets were embedded in prose. The oldest age group required additional time to detect each target type, but the largest age difference was associated with semantic search.

Adult↗