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Biomedical subjects

D Ebert

Publications and source records attributed to D Ebert.

At least 91 records · Page 5Linked to original sources
PubMed1994

Increased limbic blood flow and total sleep deprivation in major depression with melancholia.

Single photon emission computed tomography (SPECT) with technetium-99m-d,l-hexamethyl-propylene amine oxime (99Tcm-HMPAO) was carried out in 20 melancholic patients before and after total sleep deprivation. Findings in 11 responders to total sleep deprivation (defined by > or = 40% improvement on the Hamilton Rating Scale for Depression) were compared with findings in nine nonresponders. On the basis of a semiquantitative evaluation of SPECT findings, responders showed relative hyperperfusion before sleep deprivation in the right anterior cingulate cortex and in the right and left fronto-orbital cortex and basal cingulate gyrus. Responders who showed > or = 50% improvement also showed hippocampal overactivation before sleep deprivation. It is possible that limbic overactivation may characterize depressed responders to total sleep deprivation as a distinct subtype. Another possibility is that the pattern of limbic hyperactivation reflects the increased number of bipolar patients in the responder group, with response to total sleep deprivation being only a covariate of this bipolar-unipolar distinction.

Adult↗
PubMed1994

Frequency, location, and age and sex distribution of various types of gastric polyp.

Data on the frequency and location of the various types of gastric polyps are highly inconsistent. In a retrospective analysis of 5515 gastric polyps obtained from 4852 patients in the period between 1969 and 1989, including reexamination of 197 surgical, 1572 polypectomy, and 3746 biopsy specimens, the most frequent types found were Elster's glandular cysts (fundic gland polyps) (47.0%), followed by hyperplasiogenous polyp (28.3%), tubular adenoma (9.0%), adenocarcinoma (7.2%), inflammatory fibroid polyp (3.1%), carcinoid tumor (1.7%), Brunner's gland heterotopia (1.2%), and tubulopapillary adenoma (1.0%). Peutz-Jeghers polyps, juvenile polyps, and pancreatic heterotopia were found in younger patients (mean ages: 33.39 and 45 years, respectively), whereas the age of most patients (66%) with glandular cysts was between 40 and 69 years. Patients with any of the other types of gastric polyps were mostly (55-100%) over 60 years of age at the time of diagnosis. Glandular cysts, hyperplasiogenous polyps, inflammatory fibroid polyps, and carcinoid tumors were significantly more common in women, while all the other polyps were more or less equally distributed between the sexes. Glandular cysts and carcinoid tumors were relatively small (mean diameter 8 mm), and were mostly located in the corpus (100% and 83%, respectively). Medium-sized pancreatic heterotopias, Brunner's gland heterotopias, and inflammatory fibroid polyps (mean sizes 7-10 mm) were usually located in the antrum (100%, 81%, 80%, respectively), while the other polyps had an average size of between 10 and 16 mm and were distributed equally throughout the stomach.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Cortisol and beta-endorphin responses to sleep deprivation in major depression--the hyperarousal theories of sleep deprivation.

To test theories that response to sleep deprivation in depression is the result of either stress reactions or down-regulation of hyperarousal, the early morning cortisol and beta-endorphin levels of depressed sleep deprivation responders and nonresponders before and after sleep deprivation were compared (areas under the curve of 8 blood samples between 7:30 and 10 a.m.). The beta-endorphin response was significantly different in responders and nonresponders, whereas all other comparisons remained nonsignificant. The results do not support theories that sleep deprivation acts as a stressor, but are not contradictory to the hyperarousal hypothesis of sleep deprivation.

Adult↗
PubMed1994

[Benzodiazepine monotherapy in acute schizophrenia].

Two patients with acute schizophrenic or schizo-affective psychosis were treated with benzodiazepine-monotherapy. In the first patient with paranoid-hallucinatory psychosis, catatonic symptoms disappeared completely after application of Lorazepam. Side effects of neuroleptic medication (neuroleptic turbulences) were the reason for benzodiazepine treatment in the second patient. In neither patients were psychotic symptoms observed during several weeks on benzodiazepine medication. Subsequently, no further neuroleptic treatment was necessary in one patient. Benzodiazepine effects on schizophrenia are probably caused by an activation of inhibitory GABA-ergic neurons. Besides stupor and catatonia, severe side effects of neuroleptic treatment or even contra-indications of neuroleptic medication may be an indication for benzodiazepine treatment in acute schizophrenia.

Acute Disease↗
PubMed1993

Regulation and properties of extracellular signal-regulated protein kinases 1 and 2 in vitro.

Extracellular signal-regulated protein kinases (ERK) 1 and 2 and mutants of each were expressed in bacteria with a hexahistidine tag and purified using nickel-chelate chromatography. Basal activity of wild type ERK2 was approximately 2 nmol/min/mg. Self-catalyzed phosphorylation occurred in vitro on the major physiological site of tyrosine phosphorylation in an intramolecular reaction. Rabbit muscle ERK activator activated ERK2 500-1000-fold up to a specific activity (approximately 2 mumol/min/mg) approximating that of ERK1 purified from stimulated cells (Boulton, T.G., Gregory, J.S., and Cobb, M.H. (1991) Biochemistry 30, 278-286). ERK1 could also be activated by the ERK activator to the same extent. Mutants lacking the major site of tyrosine phosphorylation were autophosphorylated at a greatly reduced rate and were no longer highly activated by the ERK kinase. Mutants lacking the major site of threonine phosphorylation were autophosphorylated at the same or an enhanced rate, but the kinase activity of these mutants depended on the residue used to replace the threonine. Replacement by glutamate rendered the kinase capable of being activated by ERK activator, while replacement by alanine did not. Thus, the carboxyl group of glutamate can provide at least some of the features introduced by phosphothreonine in activated ERKs.

Amino Acid Sequence↗
PubMed1993

A test-retest study of cerebral blood flow during somatosensory stimulation in depressed patients with schizophrenia and major depression.

Six depressed patients with schizophrenia and 6 depressed patients with major depression were investigated before and during somatosensory stimulation (SS) with Tc-99m HMPAO SPECT. 8 controls were investigated only under resting conditions. The results can be summarized as follows: 1. Both psychiatric patient groups were hypofrontal (dorsolateral prefrontal cortex) compared to controls. 2. Hypofrontality was further enhanced by SS, significantly only in affective psychoses in the right inferior frontal lobe and in the right frontal hemisphere in total, in schizophrenia in the left dorsolateral prefrontal cortex. 3. Within the frontal lobes different regions were affected by SS in the two diagnostic groups. 4. In the right inferior parietal lobe SS response was significantly different in the two illnesses with schizophrenia showing a relative decrease, affective psychoses showing a relative increase of activity. 5. SS produced an increase of cerebral blood flow in subcortical regions (statistically significant contralateral to SS in thalamus and basal ganglia, ipsilateral to SS in cerebellum), a pattern which was common to all psychiatric patients. 6. Somatosensory cortex flow was not changed by SS. In conclusion, we could not fully confirm our hypotheses that similar blood flow abnormalities in different illnesses during SS are only caused by similarities in depressive psychopathology. Instead, depressed patients with schizophrenia were different from depressed patients with major depression in showing decreased activity in interrelating brain regions participating in an attentional network.

Adult↗
PubMed1993

Regulation and properties of extracellular signal-regulated protein kinases 1, 2, and 3.

The extracellular signal-regulated kinases ERK1 and ERK2 are 43- and 41-kd enzymes activated by many extracellular cues. They lie within a protein kinase cascade that is used to achieve many cellular responses. In addition to the wide variety of regulatory contexts in which they are activated, they phosphorylate important regulatory proteins, including receptors, transcription factors, cytoskeletal proteins, and other protein kinases. Thus, the stimulation of this kinase cascade is thought to have a pleiotropic action. ERK1 and ERK2 are controlled by phosphorylation on threonine and tyrosine. To understand the regulatory mechanisms, wild-type and mutant ERKs were expressed in bacteria and phosphorylated with MEK, the enzyme that is upstream of ERKs. Wild-type proteins could be activated 500- to 1,000-fold in vitro by MEK. ERK3, an enzyme of 62 kd and only 50% identical to ERK1 and ERK2 in the catalytic core, was also phosphorylated by MEK in vitro. This suggests that all three of these enzymes are targets of common signaling pathways.

Animals↗
PubMed1992

Alterations of drive in differential diagnosis of mild depressive disorders--evidence for the spectrum concept of endogenomorphic affective psychosis.

Specific alterations of drive have been cited in the literature to separate mild depressive disorders belonging to the bipolar or endogenomorphic spectrum from depressive disorders of other origin. To test this hypothesis 44 patients with mild depressive disorder were studied longitudinally. Presence of inhibition of drive or thought predicted outcome in mania or melancholia. The data are interpreted as evidence for the spectrum concept of affective psychosis.

Adult↗
PubMed1991

The early course of atypical depression.

The early course was studied of 29 atypical depressives with first onset of affective disorder not otherwise specified in DSM-III-R. Psychopathology was not stable over time in all patients, with some showing bipolar disorder or melancholia.

Adolescent↗
PubMed1991

Effects of sleep deprivation on the limbic system and the frontal lobes in affective disorders: a study with Tc-99m-HMPAO SPECT.

We studied 10 patients with melancholia before and after sleep deprivation and 8 controls with Tc-99m-hexamethylpropylenamineoxime (HMPAO) single photon emission computed tomography (SPECT). All depressed subjects showed relative hypoperfusion in the left anterolateral prefrontal cortex under both conditions. Only responders showed relative hyperperfusion in parts of the limbic system and a reduction of blood flow in these regions after sleep deprivation.

Adult↗
PubMed1991

Successful treatment of tardive akathisia with moclobemide, a reversible and selective monoamine-oxidase-A inhibitor. A case study.

Tardive akathisia (TA) is a well-documented side-effect of neuroleptic treatment. The underlying mechanism is poorly understood, and treatment is unsatisfactory. In this case report, TA that occurred in the course of a tardive dyskinesia (TD) was successfully treated with the monoamine-oxidase-A inhibitor moclobemide. With respect to the mechanism of action, it may be hypothesized that dopaminergic supersensitivity in the mesocortical region is counteracted by enhanced inhibition of primarily noradrenergic neurotransmission.

Akathisia, Drug-Induced↗
PubMed1991

An evaluation of the BD-100R rechargeable neutron bubble dosimeter.

The purpose of this paper is to present data gathered in the evaluation of the BD-100R neutron bubble dosimeter done at the University of Maryland and the Naval Research Lab. The performance of 12 dosimeters has been followed over 15 exposure-recharge cycles under a wide range of exposure conditions. Included in this paper are the results from tests on dose rate dependence, neutron energy dependence, beta and gamma exposure, and recharge cycle performance. A statistical analysis of the reusability performance of the dosimeter as a function of dose equivalent is also presented.

Evaluation Studies as Topic↗
PubMed1991

Use of the BD-100R as a neutron spectrometer through applied pressure variation.

A study was undertaken to demonstrate the feasibility of using the well-characterized BD-100R neutron bubble dosimeter as a neutron spectrometer in low-level radiation fields. The BD-100R dosimeters used in this work consisted of a test tube containing an elastic polymer with interspersed droplets of two types of Freon: Freon-12 and Freon-114. Each superheated liquid droplet is a potential nucleation site, with the minimum energy needed to form a bubble at the nucleation site being inversely proportional to the square of the difference between the applied and the vapor pressure (i.e., Emin alpha(delta P)-2. For a given dose, the number of bubbles formed continually decreases with increasing applied pressure, until a pressure is reached where no bubbles are formed, since the energy transferred can no longer vaporize the Freon. This investigation is intended to demonstrate the feasibility of measuring an unknown spectrum utilizing the dosimeter response (number of bubbles formed) as a function of the neutron energy (applied pressure). A set of 12 dosimeters was exposed under various applied pressures in a well-characterized neutron energy spectrum at the East Beam Port (EBP) of the Maryland University Training Reactor (MUTR). The dosimeters were placed inside a pressure chamber that could accommodate up to 18 dosimeters. Energy response coefficients (cross-sections) were obtained by spectral unfolding techniques on the known spectrum. The same set of dosimeters were then irradiated using a paraffin-moderated Pu/Be source. Measured spectral estimates obtained using the response coefficients were compared with numerical computations generated using the ANISN computer code. The results indicate that further research using the BD-100R as a neutron spectrometer in low radiation fields is warranted.

Neutrons↗