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Biomedical subjects

E Becker

Publications and source records attributed to E Becker.

At least 55 records · Page 3Linked to original sources
PubMed1993

Olfactory event-related potentials in psychosis-prone subjects.

Previous studies in schizophrenic patients have suggested that there are changes in olfactory sensitivity. In order to externally validate a psychometrical assessment of the psychosis-risk indicated by schizotypic factors, this study was carried out to determine whether changes in olfactory perception could be determined even for persons merely at risk of developing schizophrenia. These 'psychosis-prone' subjects consistently scored high in either the scale for 'physical anhedonia' (PA) or the scale for 'perceptual aberration' (PAB). Thus, three groups were investigated (control, n = 11; PA, n = 12; PAB, n = 12). Each subject participated in one testing session where the two odorants, vanillin (pleasant) and hydrogen sulphide (unpleasant), were applied by means of a specially designed delivery apparatus. Subjects rated both the intensity and the hedonic quality of the stimuli. In addition, olfactory event-related potentials (OERP) were recorded after dichotomous stimulation. In general, there were only few significant differences between the three groups investigated. Contrary to expectations, ratings for pleasantness of vanillin were highest in PA subjects compared to PAB subjects and controls (p < 0.05). Correspondingly, OERP amplitudes in response to vanillin were largest within the PA group (p < 0.05). For hydrogen sulphide, PAB subjects showed the smallest OERP amplitudes (p < 0.05). In addition, it was observed that female subjects had significantly larger OERP amplitudes when compared to male subjects (p < 0.05), which possibly indicates gender differences in olfactory sensitivity.

Adult↗
PubMed1993

Multifocal osteoarticular tuberculosis: report of four cases and review of management.

We report the clinical, microbiological, and radiological features of four cases of multifocal osteoarticular tuberculosis, and we review the management of this condition. In each case the initial clinical diagnosis was one of malignant disease, and the possibility of tuberculous bone infection was overlooked. There was neither clinical nor radiological evidence of pulmonary involvement in any case. Antituberculous chemotherapy was initiated in two instances on the basis of histopathologic findings compatible with tuberculous osteomyelitis; such treatment was delayed in the other two cases until the diagnosis was confirmed by culture. Antituberculous chemotherapy alone was successful in three cases, while the fourth case required emergency anterior spinal decompression as well. Two patients developed additional skeletal lesions after the initiation of appropriate antituberculous chemotherapy. Multifocal osteoarticular tuberculosis must be considered in the differential diagnosis of multiple destructive skeletal lesions in all patients from areas where tuberculosis is endemic. This condition may mimic malignant disease both clinically and radiologically.

Adolescent↗
PubMed1992

DNA amplification polymorphisms of the cultivated mushroom Agaricus bisporus.

Single 10-bp primers were used to generate random amplified polymorphic DNA (RAPD) markers from commercial and wild strains of the cultivated mushroom Agaricus bisporus via the polymerase chain reaction. Of 20 primers tested, 19 amplified A. bisporus DNA, each producing 5 to 15 scorable markers ranging from 0.5 to 3.0 kbp. RAPD markers identified seven distinct genotypes among eight heterokaryotic strains; two of the commercial strains were shown to be related to each other through single-spore descent. Homokaryons recovered from protoplast regenerants of heterokaryotic strains carried a subset of the RAPD markers found in the heterokaryon, and both of the haploid nuclei from two heterokaryons were distinguishable. RAPD markers also served to verify the creation of a hybrid heterokaryon and to analyze meiotic progeny from this new strain: most of the basidiospores displayed RAPD fingerprints identical to that of the parental heterokaryon, although a few selected slow growers were homoallelic at a number of loci that were heteroallelic in the parent, suggesting that they represented rare homokaryotic basidiospores; crossover events between a RAPD marker locus and its respective centromere appeared to be infrequent. These results demonstrate that RAPD markers provide an efficient alternative for strain fingerprinting and a versatile tool for genetic studies and manipulations of A. bisporus.

Agaricus↗
PubMed1990

Single base alterations upstream of the E. coli 16S rRNA coding region result in temperature-sensitive 16S rRNA expression.

We have isolated three new temperature-sensitive mutants of 16S rRNA, using the U1192 spectinomycin resistance as a selectable marker. These differ from our previously characterized ts mutants in that they map in the upstream leader region of the rRNA precursor (at positions -13, -30 and -59). The relative distribution of plasmid and chromosome-derived 16S rRNA is similar between 30S subunits, 70S ribosomes and polysomes at the permissive and restrictive temperatures. Processing of the 5' end of the RNA does not appear to be affected by the mutations. Second-site suppressors were found, and all of these except one (which is within 16S rRNA) were also due to point mutations in the upstream leader.

Base Sequence↗
PubMed1990

Comparison of two cognitive bedside screening instruments in nursing home residents: a factor analytic study.

The Mini-Mental State Examination (MMSE) and the Blessed Orientation-Memory-Concentration test (BOMC) were each administered to 110 nursing home residents. The correlation between the MMSE and BOMC's total score was -.79. Maximum likelihood factor analysis revealed a two-factor structure, consisting of memory-attention and verbal-comprehension factors that were highly correlated (.69). The results suggest that the somewhat longer MMSE may be preferred for bedside mental status testing, as it clearly measures an additional dimension of cognitive ability, while the BOMC is primarily a unidimensional test. The theoretical and clinical implications of bedside mental status testing of elderly patients are discussed.

Aged↗
PubMed1990

[Surgery for asymptomatic carotid stenosis: a contribution to a controversial discussion].

From 1 January 1982 to 30. June 1986, 436 operations on the internal carotid artery were performed: 164 were asymptomatic (37.6%). Morphologic indication was stenoses greater than 70% only. Supra-aortic multivessel disease played a major role. The operative mortality amounted to 0.6% (total 0.9%) and the perioperative mortality, 1.8%. The cumulative morbidity was 1.6% after the first and 1.8% after the second year, whereas the cumulative survival rate measured 89.8% after one and 80.4% after three years. Therefore surgery for asymptomatic carotid internal stenoses is justified under conditions of the restrictive indication. It also seems to be more favorable as regards early and late results.

Brain Ischemia↗
PubMed1989

Isolation of temperature-sensitive mutants of 16 S rRNA in Escherichia coli.

Temperature-sensitive mutants have been isolated following hydroxylamine mutagenesis of a plasmid containing Escherichia coli rRNA genes carrying selectable markers for spectinomycin resistance (U1192 in 16 S rRNA) and erythromycin resistance (G2058 in 23 S rRNA). These antibiotic resistance alleles, originally identified by Morgan and co-workers, enable us to follow expression of cloned rRNA genes in vivo. Recessive mutations causing the loss of expression of the cloned 16 S rRNA gene were identified by the loss of the ability of cells to survive on media containing spectinomycin. The mutations were localized by in vitro restriction fragment replacement followed by in vivo marker rescue and were identified by DNA sequence analysis. We report here seven single-base alterations in 16 S rRNA (A146, U153, A350, A359, A538, A1292 and U1293), five of which produce temperature-sensitive spectinomycin resistance and two that produce unconditional loss of resistance. In each case, loss of ribosomal function can be accounted for by disruption of base-pairing in the secondary structure of 16 S rRNA. For the temperature-sensitive mutants, there is a lag period of about two generations between a shift to the restrictive temperature and cessation of growth, implying that the structural defects cause impairment of ribosome assembly.

Ampicillin↗
PubMed1989

Inhibition of calpain in intact platelets by the thiol protease inhibitor E-64d.

E-64d, a membrane permeant derivative of E-64c, a thiol protease inhibitor (Tamai et al. (1986) J. Pharmacobio-Dyn. 9, 672-677), was tested for ability to inhibit calpain activity in intact platelets. Calpain activity was measured by proteolysis of actin-binding protein and talin, two known substrates of calpain. Incubation of platelets with E-64c (not permeant) or E-64d before lysis prevented proteolysis after lysis. When the platelets were incubated with E-64c or E-64d and then washed to remove the drugs before lysis, only E-64d inhibited proteolysis. When platelets were incubated with E-64c or E-64d and then activated with A23187 plus calcium, a treatment that activates intraplatelet calpain, only E-64d inhibited proteolysis. These results indicate that E-64d can enter the intact cell and inhibit calpain.

Blood Platelets↗
PubMed1987

Two mechanisms of CCl4-induced fatty liver: lipid peroxidation or covalent binding studied in cultured rat hepatocytes.

With cultured hepatocytes it was studied whether CCl4-induced inhibition of secretion of VLDL and HDL from liver cells is a consequence of covalent binding of CCl4 metabolites (i.e. CCl3; CCl3OO.) to cell constituents or of membrane damage by lipid peroxidation. Comparing the kinetics of inhibition of lipoprotein secretion with that of CCl4-bioactivation it was found, that covalent binding of (14C)-CCl4 occurred at early time points (5 min) after CCl4 administration and inhibited the lipoprotein secretion. At 100 microM CCl4 it was depressed by 53% within 60 min. Incubations of CCl4-treated cells with increasing concentrations of vitamin E blocked lipid peroxidation, but lipoprotein secretion was still inhibited. Piperonyl butoxid, a radical scavenger, protected against CCl4-induced inhibition of lipoprotein section, lipid peroxidation and covalent binding. These results show that during the early phases of CCl4 poisoning fat accumulation is the consequence of covalent binding of CCl4 metabolites to cell structures.

Animals↗
PubMed1987

Radiologic diagnosis of pain in the athlete.

This article provides an overview of the various radiographic procedures available today. The correct indications for the use of each of these is emphasized and illustrated.

Athletic Injuries↗
PubMed1986

Diagnostics of extra-cranial carotid stenoses. Comparison of CW-Doppler sonography and intravenous digital subtraction angiography.

In 98 internal carotid arteries, continuous-wave ultrasound Doppler sonography (USD) and i.v. digital subtraction angiography (DSA) of the internal carotid arteries were performed. The findings were compared with each other prospectively and on the basis of conventional angiography findings. The aim of this investigation was to clarify, whether DSA would show stenoses with lumen restriction of less than 50% more precisely than USD, or whether it would enable clearer localization of any vascular lesions. The results revealed that in cases of haemodynamic effective stenoses and occlusions both procedures correlated well with each other and also with catheter angiography. However, USD and DSA showed increasing discrepancies of findings with decreasing degree of severity of the stenosis. The accuracy for localization of stenoses also decreased markedly for both methods with increasing distance from the carotid bifurcation. In the case of congruent findings of USD and DSA in haemodynamic effective stenoses (degree of stenosis more than 75%) or occlusions conventional angiography did not increase the diagnostic information, and it seems therefore dispensable for vascular surgical decisions. However, in cases with existing clinical symptoms with contradictory or negative USD and DSA findings angiography is still indicated.

Adult↗
PubMed1985

The lateralization of occipital alpha-power under resting conditions in the EEG of healthy volunteers. A state- and a trait-variable.

Using a structural analysis of lateralization of occipital alpha-power in 20 healthy volunteers under resting conditions, a clear vigilance-dependence could be shown for the great majority. In contrast the state of four subjects showed almost no dependence on vigilance. Additional findings according to which these two subgroups also differ in a characteristic manner with regard to various other aspects, especially occipital alpha-quantity and vigilance dynamics, point to a maturational dimension.

Adult↗
PubMed1985

[Measurement of regional cerebral blood flow as a supplement to carotid angiography in assessing cerebrovascular insufficiency].

The examination of 91 patients was undertaken in order to establish the relevance of tomographical measurement of the regional cerebral blood-flow, following inhalation of 133Xenon, as a complementary method to the conventional carotis-angiography. In many cases the findings revealed a more precise or even deviating judgement on the hemodynamic relevance of stenosis and obliteration than was proved only by angiography. Especially in the stages I and IV of cerebrovascular disease of the a. cerebri anterior, a. carotis interna and a. carotis communis the rCBF-measurement seemed to be an important parameter for the decision between conservative and surgical therapy as a prognostic parameter for the individual risk of many patients to suffer a cerebral infarction.

Carotid Arteries↗