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Biomedical subjects

B Spring

Publications and source records attributed to B Spring.

At least 37 records · Page 2Linked to original sources
PubMed1989

Psychobiological effects of carbohydrates.

The authors studied whether the fatiguing effects of eating lunch are greater for carbohydrate-rich meals than for other meals, and related the time course of behavioral change to plasma glucose, insulin, and amino acids. On different occasions, in counterbalanced order, normal women (N = 7) fasted overnight, ate a standard breakfast, and at lunch either continued to fast or ate a high-carbohydrate, low-protein meal; a hedonically similar meal containing both carbohydrate and protein; or a high-protein, low-carbohydrate meal. Meals were isocaloric and equated for fat content. Only the carbohydrate meal significantly increased fatigue, which could not be attributed to hypoglycemia because plasma glucose remained elevated. Fatigue began approximately, when the carbohydrate meal elevated the plasma tryptophan ratio but ended even though the ratio remained elevated. Fatigue after a high-carbohydrate lunch could not be explained by reactive hypoglycemia or sweet taste, and could partially be explained by the hypothesis that fatigue parallels an elevation of the tryptophan ratio.

Adolescent↗
PubMed1989

Distractibility in schizophrenia: state and trait aspects.

This report compared the selective attention of 19 schizophrenic in-patients, 10 recently discharged schizophrenic out-patients, 21 schizophrenic out-patients in stable clinical remission, 33 first-degree relatives of schizophrenics from 15 families, 25 students who scored deviantly on questionnaire measures of magical ideation, perceptual aberrations, and physical anhedonia, and 20 normal controls. Results indicated that distractors only disrupted the performance of schizophrenic in-patients, suggesting that differential deficits in selective attention are a marker of episodes of schizophrenia. A propensity to interject phonemes from the distracting message was found not only in patients in or just emerging from a psychotic episode, but also in the remaining vulnerable but non-psychotic groups, suggesting that intrusion errors might be a mediating vulnerability marker. The findings suggest both state and possibly trait aspects to distractibility in schizophrenia.

Adult↗
PubMed1989

Anticholinergic effects on memory: benztropine versus amantadine.

To evaluate anticholinergic effects on cognition and other functions, we studied 60 healthy volunteers in a double-blind crossover trial of two antiparkinsonian agents, benztropine and amantadine. Benztropine 4 mg/day, but not amantadine 200 mg/day, impaired free recall and perception of time, and subjects' perception of their own memory impairment was significantly greater with benztropine. Side effects in general were worse with benztropine, particularly such anticholinergic effects as dry mouth and blurred vision, and benztropine decreased measured salivary flow to a significantly greater degree than amantadine. Our findings support the hypothesis that drugs that decrease cholinergic transmission impair storage of new information into long-term memory, but have little effect on retrieval from memory or on tasks involving only immediate memory. Clinically, anticholinergic agents can levy a considerable burden on memory and time perception.

Adolescent↗
PubMed1987

Effects of amantadine and trihexyphenidyl on memory in elderly normal volunteers.

Anticholinergic drugs impair one's ability to learn new material, even at routine clinically used doses. During the trihexyphenidyl phase of this double-blind crossover trial, elderly normal subjects complained of confusion and memory impairment and demonstrated a pattern of deficits in memory function compatible with that previously reported to result from anticholinergic drugs. The subjects neither complained of nor demonstrated memory impairment while taking amantadine, which is believed to exert its pharmacological effects upon extrapyramidal disorders via dopaminergic mechanisms and does not appear to be associated with memory impairment. Anticholinergic drugs should be avoided whenever possible in the elderly and especially in those suffering dementia.

Age Factors↗
PubMed1986

Gamma ray-induced mutants as a tool for the production and characterisation of monoclonal antibodies against HLA-alloantigens.

To simplify the screening procedure for murine monoclonal antibodies specific for polymorphic HLA determinants, spleen cells from a mouse immunized with the human cell line BJAB-B95.8.6 were fused with NS1 mouse myeloma cells, and hybridoma supernatants were screened for their reactivity on BJAB-B95.8.6 and two gamma ray-induced HLA-loss mutants of this line. The use of these HLA-loss mutants allowed the rapid identification of two new allospecific MOABs designated TU160 and TU161. Serological as well as biochemical studies revealed TU160 to be specific for HLA-A2, and TU161 for HLA-B13 molecules, respectively. Both MOABs were determined to be antibodies of the IgG class and were able to precipitate their antigens from lysates of radioactively labeled cells.

Animals↗
PubMed1985

Refinement of HLA gene mapping with induced B-cell line mutants.

The lymphoma cell line BJAB.B95.8.6 was gamma-irradiated to induce mutations of major histocompatibility complex (MHC) encoded genes. Cloned "wild-type" cells were phenotyped HLA-A1, A2, B13, B35, Bw4, Bw6, Cw4, DR5, DRw52, DQw1, DQw3, DPw2, DPw4, GLO1 1, PGM3 2-1, and ME1 0 and possessed two apparently normal chromosome 6s prior to mutagenesis. Loss mutants were selected 5 days after 3 Gy gamma-irradiation employing three complement-fixing monoclonal antibodies specific for HLA-A2 (TU101) and Bw4 (TU48, TU109). Fifteen independently arising mutants were isolated and cloned. Typing with monospecific alloantisera and cell-mediated lympholysis revealed the presence of HLA-A1, B35, Bw6, Cw4, DR5, DRw52, DQw3, and DPw4 specificities on all mutant clones. HLA-A2, B13, and Bw4 were absent. Mutants differed in their expression of class II antigens. One group retained DQw1 and DPw2, another was DQw1-, DPw2+, and a third was DQw1-, DPw2-. Karyotyping of the "wild-type" line and selected mutant clones showed that the loss of HLA specificities correlated with deletions which map the HLA-A and -B loci directly to the distal part of the 6p21.33 region and the class II genes to the region 6p21.33 (proximal) to 6p21.31 (distal) on the short arm of chromosome 6.

Antibodies, Monoclonal↗
PubMed1985

A double-blind comparison of clovoxamine and amitriptyline in the treatment of depressed outpatients.

Forty-two outpatients with major depression were treated in a 4-week double-blind parallel-group comparison of the new antidepressant clovoxamine--a member of oximethers of aralkylketones--with amitriptyline. The two drugs were comparable in efficacy, although because of the small sample size a moderate clinical difference between treatments may not have been detected. The magnitude of unwanted effects also was comparable, but clovoxamine produced fewer "anticholinergic" effects; this was determined by patient complaints of typical anticholinergic symptoms, by decreased salivary flow, and by a new signal detection memory test.

Adolescent↗
PubMed1984

Effects of two antidepressants on memory performance in depressed outpatients: a double-blind study.

Forty outpatients with primary depression were randomly assigned on a double-blind basis to treatment with amitriptyline (a tricyclic antidepressant) or clovoxamine (a nontricyclic, experimental antidepressant). Memory and depression were assessed during a pretreatment baseline period and at the end of days 4, 7, and 28 of drug treatment. A signal detection recognition memory task and conventional memory measures (including the Benton Visual Retention, Wechsler Logical Memory, and verbal learning tests) were used to assess memory. Although both drugs led to comparable clinical improvement in depression, they affected memory performance differently. The signal detection recognition memory task detected an impairment in memory after chronic amitriptyline administration, as contrasted with an improvement in memory after chronic administration of clovoxamine. The memory impairment in the amitriptyline group and improvement in the clovoxamine group were the result of changes in sensitivity [P(A)]. No changes in response bias (B) were detected. Conventional memory tests failed to detect drug-related differences in memory between the two groups. On the Benton, errors decreased over time within both drug treatment groups, whereas correct reproductions increased within the amitriptyline group only. However, between-group differences on the Benton did not reach significance. Results from the signal detection task suggest an amitriptyline-associated memory impairment. However, this interpretation is tempered by the finding that conventional memory measures failed to detect differences in memory performance between the two groups. We discuss the limitations of traditional memory measures and the utility of a signal detection approach in studies of psychopharmacologic influences on memory.

Adult↗
PubMed1984

Recent research on the behavioral effects of tryptophan and carbohydrate.

Animal and human studies indicate that diet can alter plasma and brain concentrations of neurotransmitter precursors, with possible implications for the synthesis and release of brain neurotransmitters. The best known example is serotonin, whose synthesis is limited by the availability of its precursor, tryptophan, in the brain. Consuming tryptophan or a carbohydrate-rich, protein-poor meal increases brain levels of tryptophan and serotonin. Although a carbohydrate meal itself lacks tryptophan, the meal causes insulin to be secreted. Insulin, in turn, decreases plasma levels of large neutral amino acids that would ordinarily compete with tryptophan for transport across the blood-brain barrier. Resulting brain changes in serotonin provide a plausible mechanism whereby diet could affect behaviour. Research on human subjects suggests that ingesting tryptophan or carbohydrate can reduce subjective alertness and possibly influence some aspects of objective performance. Effects on sleep latency and on pain perception have also been detected. Behavioral effects may come about via the action of tryptophan on brain serotoninergic pathways, although other mechanisms may operate and must still be ruled out before the mechanism is certain.

Adult↗
PubMed1981

Stress and schizophrenia: some definitional issues.

This article discusses definitional ambiguities in research on the role of stress in the etiology of schizophrenia. Implications of the change to DSM-III criteria are considered, as is the question of whether prior research samples have overincluded acute schizophrenics. It is suggested that the problem of defining schizophrenia's time of onset is one of the thorniest in this literature. Three different operational definitions of stress are examined. Stress may be considered a response involving disruption in homeostasis, or as a stimulus with objectively specifiable properties. Stress is also defined interactionally with reference to characteristics of the individual and the surrounding life context. Relative merits of the three definitions are evaluated, and an attempt is made to clarify the differentiation between formative and triggering effects of stress. Further study of the impact of remote life events on vulnerability is encouraged.

Humans↗
PubMed1980

Auditory sensitivity in psychiatric patients and non-patients: monotic click detection.

The sensitivity in detecting a click was measured separately for the right and left ear of psychiatric patients and non-patient controls using a three-interval forced-choice staircase procedure. Patients with affective disorders showed reduced right ear sensitivity, while schizophrenic patients did not show reduced sensitivity. Lower sensitivity correlated with higher structured-interview ratings of speech retardation.

Adolescent↗