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Biomedical subjects

S E Mason

Publications and source records attributed to S E Mason.

32 records · Page 2Linked to original sources
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

Expression of tobacco mosaic virus coat protein by a cauliflower mosaic virus promoter in plants transformed by Agrobacterium.

The 35S transcript promoter of cauliflower mosaic virus directs the synthesis of an abundant RNA in infected leaf tissue that is both a template for reverse transcription during virus replication and also a polycistronic mRNA. The 35S promoter was isolated and linked to a cDNA of the 3' end of tobacco mosaic virus that encodes the coat protein of this single-stranded RNA virus. After transformation of this gene construction into tobacco plants using a disarmed Agrobacterium binary vector, viral coat protein synthesis was detected in transformed leaf tissue. A chimaeric 35S coat protein RNA was detected in transformed callus.

Journal Article↗
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↗
PubMed1978

Popliteal vein thrombosis secondary to popliteal artery aneurysm.

Two patients with popliteal vein thrombosis secondary to popliteal artery aneurysm are described. The association of venous abnormalities in 623 reported cases of popliteal artery aneurysm is reviewed. The high morbidity from popliteal vein thrombosis would seem to justify preoperative leg venography in patients with popliteal artery aneurysm.

Aneurysm↗
PubMed1977

Imagery in the aged.

Two studies were conducted to investigate the use of imagery by subjects of different ages. Experiment 1 was designed to test the effectiveness of "peg-word" system as a memory aid for the elderly. Variables believed to be important in the effectiveness of mnemonic devices were manipulated. The results showed that the mnemonic and imagery instructions were of benefit to the young subjects but not to the older subjects. Age was also found to interact with the concreteness variable, item concreteness having a smaller effect on the oldest subjects. These results suggest that the older subjects were not using imagery mediation effectively. Under the conditions of the second experiment, however, item concreteness had a similar effect across age groups. Tye of instruction was also manipulated in Experiment 2 and only the middle age group improved with imagery instructions. The older age group was not benefited by such instruction.

Adult↗