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Biomedical subjects

W Becker

Publications and source records attributed to W Becker.

At least 469 records · Page 26Linked to original sources
PubMed1983

The role of canal-neck interaction for the perception of horizontal trunk and head rotation.

The present report considers the conscious perception of passive horizontal rotations of the trunk, the head, or both, by human observers. It examines in particular how this perception depends on the interaction of canal and neck afferents. Three sets of sinusoidal stimulations (0.2 Hz) were applied to subjects (Ss): Rotations of (1) whole body (pure labyrinthine stimuli, lambda), of (2) only the trunk with the head stationary in space (pure neck stimuli, nu), and of (3) both head and trunk, each with an amplitude and a direction of its own, giving rise to various in-phase and counter phase combinations of lambda and nu.--The Ss were to estimate the magnitude of their turning sensations (psi). In doing so, they were to concentrate either on the rotation of their trunk in space (TS) or of their head in space (HS), or of the head relative to the trunk (HT). The TS and HS turning sensations induced by pure lambda-stimuli were essentially the same as to magnitude and direction. Pure nu-stimulation also led to TS and HS turning sensations. However, the former had the direction of the trunk-to-head (T delta S) deflection, the latter that of the head-to-trunk deflection. The nu-induced HS turning sensation represented an illusion, since the head remained stationary in space. When the lambda- and nu-stimuli were combined, the interaction could be described by a linear summation of their effects. The estimates of TS turning followed the equation psi HS approximately lambda-nu, thus well reflecting the actual TS rotation. The estimates of HS could be described by psi HS approximately lambda+k nu; the term k nu represents the "nu-illusion" contaminating the HS turning sensation. The estimates of HT turning were roughly proportional to nu alone and, therefore, close to the actual HT rotation. We conclude that humans may derive a rather faithful information about trunk rotation from the combined activation of canal and neck afferents, but that the sensation of passive head rotation is contaminated by an (illusionary) contribution from neck afferents. These additive and subtractive modes of interaction have parallels in postural reflexes as well as in neuronal responses that are known from cat.

Adolescent↗
PubMed1983

Condensing osteitis of the clavicle in childhood: a rare sclerotic bone lesion. Review of literature and report of seven patients.

Seven children and adolescents with sclerotic and periosteal alterations of the clavicle are reported, two of them in detail. Malignancies and bacterial inflammatory processes, which were first suspected, could be excluded. Clinical and radiographic features as well as differential diagnosis are discussed, as is the pertinent literature. The etiology of this uncommon bone lesion, which is described under different names, could not be clarified.

Adolescent↗
PubMed1983

Tolerance to ethanol in rats bred on essential fatty acid deficient diets.

We bred three generations of Sprague-Dawley rats on a diet deficient in essential fatty acids, low-EFA (0.3 energy %), whereas age matched controls received normal-EFA (3.0 energy %). Subgroups (N = 6) of female rats were given daily IP injections of ethanol (3.0 g/kg) or isocaloric glucose for 23 consecutive days. On days 1 and 22 blood-ethanol profiles, rates of ethanol metabolism and ethanol-induced impairment of motor coordination were measured after the challenge dose of 3.0 g/kg. Rats exposed to ethanol ate and drank more than controls and gained more body weight over the 23 days. Low-EFA rats were slightly more impaired than normal EFA rats after an acute dose of ethanol even though the peak blood ethanol concentrations reached were about the same at 2.9 mg/ml (63 mmol/l). After chronic ethanol treatment a functional tolerance developed in both dietary groups but the degree of tolerance was less clearcut in low EFA rats. Metabolic tolerance was confirmed after chronic treatment in both dietary groups as shown by steeper slopes (19-27%) of the ethanol elimination curves. But no significant differences in the development of metabolic tolerance were apparent in rats on low EFA and normal EFA diets.

Animals↗
PubMed1983

Purine metabolism in Biomphalaria glabrata under starvation and infection with Schistosoma mansoni.

Purine content and its alterations during a starvation period of 29 days and an infection period of 52 days were studied. During starvation the amount of uric acid increased from 2.11 +/- 0.95 mg/g dry wt in control snails to a maximum of 6.73 +/- 3.99 mg/g dry wt on day 29 of starvation for uric acid and from 4.73 +/- 2.10 mg/g dry wt in control snails to a maximum of 11.29 +/- 3.48 mg/g dry wt on day 23 of starvation for guanine. During infection there was an increase with both uric acid and guanine to maximum on day 40 post infection (7.17 +/- 3.51 mg/g dry wt for uric acid, 14.83 +/- 4.53 mg/g dry wt for guanine) and a decrease afterwards. Of all the snails' organs tested, only in the kidney were purines detectable, but it was impossible to find excreted purines.

Animals↗
PubMed1983

[Computer tomographic study of acute renal tuberculosis].

The course of an acute renal tuberculosis was demonstrated by computed tomography. The kidney presented coarse cystic lesions which were of water density. Subsequently a non-specific abscess occurred in the opposite kidney with a significantly higher density following intravenous contrast injection.

Acute Disease↗
PubMed1983

[The old and the recently occurring endocrine ophthalmopathy in computed tomography: similarities--differences].

Thirty patients are described on whom computed tomography was carried out because of endocrine ophthalmopathies. Fifteen patients had had the disease for more than two years, in the others it was acute. Determinations of muscle thickness and Hertel values show that there is no thickening of the extraocular muscles in patients with longstanding disease, but a significant increase in the Hertel values. Patients with recent disease show a definite increase in muscle thickness and corresponding protrusion of the globe, which can be explained by the changes in the muscles. The computer tomographic appearances of the striated ocular muscles in long-standing disease can be explained by fibrosis. These characteristics are of significance when considering the indications for radiation therapy.

Exophthalmos↗
PubMed1983

Effects of dietary essential fatty acids on active thermogenin content in rat brown adipose tissue.

Rats were fed diets providing either 0.3% (low EFA), 3% (control) or 10% (high EFA) of the energy as essential fatty acids. (All diets provided 20 energy percent of fat.) Both the experimental groups had a lower body weight than the controls. Small differences were found between the groups in many traditional parameters of brown adipose tissue activity (wet weight, protein content, mitochondrial content, cytochrome c oxidase activity). A specific increase in the mitochondrial concentration of the 32,000-dalton GDP-binding protein thermogenin was observed in the high EFA group (from 0.30 to 0.45 nmol/mg). When the thermogenin content of the animal was expressed per gram body weight, the content was more than doubled (from 22 to 47 pmol/g body weight) in the high EFA group, but was unaltered in the low EFA group. It is concluded that the effect of low EFA is nonspecific and due to a general decrease in health status. The effects of high EFA are, however, specific and resemble the changes observed in animals exhibiting diet-induced thermogenesis. It is suggested that the animals fed high amounts of essential fatty acids are in a state of decreased metabolic efficiency and this may be at least in part an explanation for their low body weight.

Adipose Tissue, Brown↗
PubMed1983

Saccadic eye movements in psychiatric patients.

Saccadic eye movements were examined in 110 psychiatric patients and 26 controls, evaluating three parameters, the frequency of dysmetric saccades, nonfixation and the saccadic reaction time. Dysmetric saccades (dysmetria) were defined as saccadic reactions undershooting the target, nonfixation was defined as a deviation of the gaze from the target with the target stationary. While the nonfixation score and the saccadic reaction time were slightly increased in most of the psychiatric patient groups as compared to controls, an increase of the dysmetria score was confined to patients with schizophrenic and schizoaffective disorders. Dysmetria is thus interpreted as the expression of a relatively specific impairment of attention in these patients.

Adult↗
PubMed1983

Autoradiographic studies with albumin-bound 1-14C-linoleic acid in normal and essential fatty acid-deficient rats. A pilot study.

Young rats fed a diet providing 0.3, 3 or 10% of the energy as essential fatty acids (EFA) were given a single intravenous dose of albumin-bound 1-14C-linoleic acid. 1 animal from each group was killed at 1 and 18 h, respectively, after the injection and submitted to whole-body autoradiography. In general, the activities in the tissues were higher in the 0.3% group than in the other groups, whereas the differences between the 3% and the 10% group were small. In all groups the highest activity occurred in the brown fat. High activities were also noted in the liver, the adrenal cortex, the diaphragm, and the gastric and intestinal mucosa. The higher activities in the tissues of the rats fed 0.3% than in the tissues of those fed 3% or 10% EFA probably reflect a higher incorporation of fatty acids of the linoleic acid series into structural and other lipids in the former group due to the lack of EFA.

Adipose Tissue, Brown↗
PubMed1983

[Direct and indirect parameters for free thyroxine. II. Diagnostic accuracy in disorders of thyroid function and binding protein anomalies].

Part II of the study concerning the clinical applicability of direct and indirect parameters for free thyroxine evaluates the diagnostic accuracy of the FT4-RIAs ImmoPhase, GammaCoat, Liquisol, Amerlex and LisoPhase in relation to FT4 index and T4/TBG ratio. This comparison of methods is done on a thoroughly classified collection (n = 640) of patients with normal and impaired thyroid function including patients with binding protein anomalies (pregnancy, estrogen-medication, phenytoin therapy, renal protein loss). FT4 normal ranges of a given kit harmonize well with data of the manufacturers and of the literature. On the other hand, the normal ranges of the various kits are not comparable. The differentiation of euthyroidism from hyper- or hypothyroidism can be made without problems using any of these methods, with the exception of the FT4-RIA GammaCoat. As expected, patients with euthyroid goiter show, on the average, slightly lower parameters for FT4. In pregnancy all direct and indirect parameters for FT4 have a tendency to lower values after the first trimester. This trend is most distinct for the T4/TBG ratio. A weak negative correlation of FT4 parameters with basal TSH, which does not exceed the upper normal range, however, can be interpreted in the sense of a relative hypothyroxinemia. Under contraceptive estrogen medication FT4 parameters do not fall outside the normal range, with the exception of the FT4-RIA ImmoPhase assay which yields a significantly increased frequency of high FT4 levels. On therapy with phenytoin FT4 values are generally lower than in controls. FT4 parameters in patients with renal protein loss of more than 2 g daily do not behave uniformly. While three of the FT4-RIAs tested (ImmoPhase, GammaCoat, Amerlex) show a tendency to lower values, the results of the remaining FT4 parameters do not differ significantly from the distribution of normals. The study leads to the conclusion that indirect FT4 parameters are still useful in the diagnosis of thyroid function; currently available FT4 radioimmunoassays may yield comparable results. With regard to the varying quality of the various commercial test kits, the choice between FT4-RIAs and indirect FT4 parameters does not depend primarily on clinical but on technical viewpoints.

Adult↗
PubMed1983

[Budd-Chiari syndrome: the CT image].

The article reports on the CT image of a venous thrombosis of the liver with severe parenchymal damage (Budd-Chiari's syndrome) in a young woman, resulting in her death. The x-ray morphology image showed a liver pattern of reduced density in spot form with hepatomegaly and ascites. The hypodense areas were both circumscribed and disseminated over both lobes with density values between +15 and +30 HE. Enlargement of the lobus caudatus is considered as typical of the disease (4, 7).

Adult↗