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Biomedical subjects

R E Becker

Publications and source records attributed to R E Becker.

At least 37 records · Page 2Linked to original sources
PubMed1990

Different tissue distribution and hormonal regulation of messenger RNAs encoding rat insulin-like growth factor-binding proteins-1 and -2.

The insulin-like growth factor-binding proteins IGFBP-1 and IGFBP-2 are low mol wt IGFBPs that are similar in structure. They are not glycosylated and have a homologous amino acid sequence, including the number and position of 18 cysteine residues and a carboxyl-terminal Arg-Gly-Asp sequence that can be recognized by cell adhesion receptors. The present study demonstrates that expression of mRNAs encoding the two BPs differs in some fetal rat tissues and in the livers of adult rats after hypophysectomy, fasting, or streptozotocin-induced diabetes. As determined by Northern blot hybridization using cDNA probes for rat IGFBP-2 or human IGFBP-1, both mRNAs are expressed at high levels in liver of 21-day gestation and 1-day-old rats and at lower levels in 21- and 65-day-old rat liver. Levels of both mRNAs are higher in liver than in other fetal rat tissues. The relative abundance of the two mRNAs in most fetal tissues is similar to that in liver, except that kidney and brain have 8-fold and more than 25-fold higher relative levels of IGFBP-2 mRNA, respectively. IGFBP-2 mRNA is about 10- to 20-fold increased after hypophysectomy or fasting, whereas IGFBP-1 mRNA is relatively unchanged. IGFBP-2 mRNA levels are decreased completely by refeeding fasted rats for 3 days, but only partially decreased by treatment of hypophysectomized rats with GH, cortisone acetate, T4, and testosterone for 4 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1989

Identification of a type 1 insulin-like growth factor binding protein (IGF BP) in serum from rats with diabetes mellitus.

Circulating insulin-like growth factor binding protein (IGF BP) activity is increased in animals with streptozotocin-induced diabetes. Separation of BPs by SDS/PAGE for ligand and immunoblot analysis revealed that a 32,000 molecular weight BP is present and increased in diabetic serum. This BP is immunologically distinct from the low molecular weight fetal rat BP (rBP2) and is related to the human amniotic fluid BP (hBP1) that is increased in patients with insulin dependent diabetes mellitus.

Affinity Labels↗
PubMed1989

Neuropsychological "systems efficiency" and positron emission tomography.

Positron emission tomography (PET) has dramatically improved our ability to examine the functioning of the living brain. PET studies of neural pathways of the major sensory modalities--auditory, visual, somatosensory--have confirmed many traditional neuropsychological concepts, such as cross-lateral representation and regional functioning to particular primary sensory cortical areas. Other PET studies have used radioisotopes to examine relationships between radiopharmaceutical agents and neurobehavioral functioning in both normal and neuropathological states. In some areas, PET methodology requires further refinement. For example, effort should be made to develop the technology to do multiple scans within a short time frame; statistical procedures to examine relationships between neuropsychological tasks and the activity or presence of radiopharmaceutical agents in multiple sites; adequate controls for experimental error; and activation paradigms controlling the nonspecific effects of simple arousal. PET activation models of cognition suggest that a "systems efficiency" approach to assessing neuropsychological test performance involving both serial and parallel processing would be useful. These developments will improve empirical methodology and our understanding of brain-behavior relationships.

Arousal↗
PubMed1989

Clinical pharmacology of tetrahydroaminoacridine: a possible therapeutic agent Alzheimer's disease.

Tetrahydroaminoacridine (THA) was administered to a small number of patients with Alzheimer's disease. A minority of patients received the drug for longer than one week. Only one investigator [Summers et al. 1986] has reported dramatic palliative effects from the administration of THA. All investigators other than Summers reported side effects, especially troublesome is the frequent appearance of indications of hepatotoxicity. The efficacy and safety of THA are unknown. There is evidence that THA may have complex modes of action in addition to the inhibition of cholinesterases. There is a need for careful clinical assessment of THA and for further investigation of possible mechanisms of action.

Alzheimer Disease↗
PubMed1989

Determination of physostigmine in plasma and cerebrospinal fluid by liquid chromatography with electrochemical detection.

Physostigmine (Phy) was determined in plasma and cerebrospinal fluid (CSF) by HPLC with electrochemical detection, with use of a normal-phase column and methanolic sodium acetate buffer, pH 4.6. The detection limit of the method was 0.5 micrograms/L for a 2-mL sample of plasma or 0.5 mL of CSF. Analytical recovery of Phy in the range from 0.5 to 40 micrograms/L was 60% (SD 5%) for plasma and 78% (SD 8%) for CSF. Excellent chromatographic separation of Phy without column deterioration during extended usage and constant recovery for a wide range of Phy concentrations makes the routine monitoring of plasma from patients with Alzheimer's disease economically feasible. Using our method, we measured Phy in 13 such patients' plasmas at 105 and 135 min after a 135-min intravenous infusion of 300, 600, and 900 micrograms of Phy per square meter of body surface. Mean values significantly increased with dose (P = 0.001), but differences between 105 and 135 min (P = 0.229) or between dose and time (P = 0.949) were not significant.

Alzheimer Disease↗
PubMed1988

Depression in schizophrenia.

Depressive syndromes that occur during the course of schizophrenia are not clearly understood but have important implications for the treatment of the schizophrenic patient. In this review of the literature on depression secondary to schizophrenia, the author notes that lack of tested diagnostic criteria has led to a misunderstanding of its relatively high frequency and its association with poor outcome features such as impaired psychosocial functioning, schizophrenic relapse, and suicide. Differential diagnosis, including ruling out akinetic depression, is essential, he believes, partly because the concept of schizophrenic depression as postpsychotic is not supported by evidence. Clinical management must address such increased risk factors as relapse and suicide, but evidence indicates that secondary depression in schizophrenia does not respond to antidepressant medication.

Depressive Disorder↗
PubMed1987

Genes for immunodominant protein antigens are highly homologous in Mycobacterium tuberculosis, Mycobacterium africanum, and the vaccine strain Mycobacterium bovis BCG.

The relatedness of immunodominant protein antigens in Mycobacterium tuberculosis, M. africanum, and M. bovis BCG was investigated by comparing the genes that encode major protein antigens in M. tuberculosis with their counterparts in the other two mycobacteria. Genes encoding homologs of M. tuberculosis major protein antigens were isolated from M. africanum and M. bovis BCG by constructing lambda gt11 recombinant DNA expression libraries and screening them with murine monoclonal antibodies and DNA probes. The antibodies were directed against four major protein antigens of M. tuberculosis with molecular masses of 71, 65, 19, and 14 kilodaltons. The isolated M. africanum and M. bovis BCG DNA clones were mapped with restriction endonucleases, and the maps of the mycobacterial genes were confirmed by Southern analysis of mycobacterial genomic DNA. The restriction maps of DNA containing the four genes in M. tuberculosis, M. africanum, and M. bovis BCG are identical, indicating that the immunodominant proteins that they encode are highly homologous in the three mycobacteria. Thus, the immunity against tuberculosis engendered by M. bovis BCG vaccination could be provided, at least in part, by the immune response to these homologous antigens.

Antigens, Bacterial↗
PubMed1985

Characterization of the bupropion cue in the rat: lack of evidence for a dopaminergic mechanism.

Using a two-lever operant task rats were trained to discriminate 40 mg/kg IP of bupropion from saline. Despite bupropion's established dopaminergic activity in vitro and in vivo, it was found that the bupropion cue was neither mimicked by the dopaminergic drugs L-DOPA and bromocriptine nor blocked by a variety of neuroleptics (haloperidol, thioridazine, and thiothixene). In addition, bupropion was active in attenuating the behavior-suppressing effects of haloperidol, unlike amphetamine and the atypical antidepressants, nomifensine and viloxazine. The bupropion cue was not mimicked or disrupted by adrenergic or serotonergic drugs, but it did generalize to some stimulants (amphetamine, cocaine and caffeine) as well as to nomifensine and viloxazine. The generalizations were blocked by neuroleptics. These data indicate that bupropion's cue properties may not be based on its ability to modulate dopaminergic receptor activity. The possible involvement of phenylethylamine in the bupropion cue is also discussed.

Animals↗
PubMed1985

Evaluations and consequences of assertive behavior.

Male and female high assertive and low assertive subjects observed videotaped scenes of actors exhibiting assertive, empathic-assertive, and nonassertive behavior in response to unreasonable requests made by acquaintances. Subjects provided evaluative ratings of actors in the different scenes and rated the likelihood of various consequences that might follow from the actors' behaviors. Generally, empathic-assertive behavior was more positively received than assertive behavior. Empathic assertion received high ratings on dimensions of competence and likeability and was associated with expectations of positive consequences of a social (i.e. requestor's reactions to the actor's behavior) or personal (i.e. the actor's own feelings) nature. In contrast, both empathic-assertion and assertion were believed to result in more negative long-term consequences (i.e. the effect the actor's responses will have on the relationship in the long run) than nonassertive behavior. These effects were modified by the sex of the requestor and the sex and assertiveness of the subject, but unaffected by the sex of the actor. Implications of these findings for research and training of assertive behavior are discussed.

Assertiveness↗
PubMed1985

Treatment of social phobia by exposure, cognitive restructuring, and homework assignments.

Seven patients who experienced clinically significant anxiety in situations involving public speaking or heterosexual performance and who had received a DMS-III diagnosis of social phobia participated in a 14-week program of cognitive-behavioral treatment. Treatment was conducted in a group format and consisted of: imaginal exposure, in which patients visualized their own participation in phobic events; performance-based exposure, in which patients enacted simulated phobic situations during sessions; cognitive restructuring, in which patients' cognitions experienced during exposure situations were assessed and analyzed; and systematic homework assignments involving the confrontation of environmental events previously simulated in the group. Self-report, behavioral, and physiological measures of anxiety were collected weekly during baseline and treatment periods, and additional measures were collected before and after treatment. After treatment, most patients demonstrated significant gains, and improvements were maintained at 3-month and 6-month follow-ups.

Adult↗
PubMed1985

Clinical significance, evaluation, and management of secondary depression in schizophrenia.

Treatment of the chronic schizophrenic patient is often complicated by depressive symptoms that can be difficult to detect. Because of the association between depressive symptoms and poor outcome features, the presence of these symptoms has substantial treatment implications. Treatment issues for depressive schizophrenic patients include selecting appropriate drug therapy, overcoming high rates of noncompliance, dealing with self-doubt and social withdrawal, and protecting patients from recurrent depressive symptomatology, suicide, or psychotic relapse. Controlled studies suggest that neuroleptic therapy is the drug treatment of choice; addition of an antidepressant does not appear to enhance therapeutic efficacy and may be associated with increased adverse effects. Successful treatment also requires the use of assertive case management, community support, family support, and careful patient education.

Adult↗
PubMed1985

Diagnosis of secondary depression in schizophrenia.

Four diagnostic groups were studied to determine the relationship of depression secondary to schizophrenia to DSM-III major depression criteria and Hamilton Depression Rating Scale scores. The symptoms found in schizophrenic patients with major-type depressions differed qualitatively from those in primary depressives. Some of the criteria used to diagnose depression in schizophrenic patients (retardation and insomnia) probably arise from the schizophrenic syndrome. Since secondary depression in schizophrenia is associated with poor outcome, it is important that specific diagnostic criteria for distinguishing depressed from nondepressed schizophrenics be developed. Such criteria should not include symptoms that are part of the schizophrenic syndrome.

Adult↗
PubMed1984

Bupropion hydrochloride.

Bupropion is a trimethylated monocyclic phenylaminoketone that is an effective antidepressant in humans. It neither is sedating, anticholinergic, nor cardiotoxic. Its mechanism of action may be related to dopamine, but remains uncertain at this time. Clinical trials comparing bupropion 300-750 mg/d with placebo show it to be superior to placebo in efficacy and as well tolerated. Bupropion, in controlled clinical trials, is as effective as amitriptyline or imipramine, with fewer side effects. The only clinically significant adverse reaction to bupropion in more than 1000 patients studied has been seizure induction at a frequency comparable with that of imipramine. Bupropion appears to be safe and effective in both adult and geriatric depressed patients. Although it appears to be safer and equally efficacious when compared with currently used antidepressants, it has not been tested by routine clinical use.

Animals↗