Biomedical subjects
Publications and source records attributed to J M Berger.
In a large commercial goat farm rickets-like symptoms were diagnosed in goat kids. The disease was probably caused by the synthetic milk which was freely available to the kids. The milk feed was for calves and had a calcium-phosphorus ratio of 0.83:1.
In a previous study, a genetic screening procedure was used to identify variants of bovine pancreatic trypsin inhibitor that can fold to an active conformation but that are inactivated much more rapidly than the wild-type protein in the presence of dithiothreitol (DTT). The mechanisms by which 30 of these DTT-sensitive variants are inactivated have now been investigated. Some of the amino acid replacements cause rapid inactivation in the presence of DTT because the three disulfides of the native protein are reduced up to 300-fold faster than for the wild-type protein, leading to complete unfolding. Other substitutions, however, do not greatly increase the rate of complete reduction and unfolding but lead to accumulation of an inactive two-disulfide species. There is a striking correlation between the locations of the DTT-sensitive amino acid replacements in the three-dimensional structure of the protein and the mechanisms by which the variants are inactivated. All of the substitutions that cause rapid unfolding are clustered at one end of the folded protein, in the vicinity of the two disulfides that are reduced most slowly during unfolding of the wild-type protein, while substitutions of the other class are all located at the other end of the protein, near the trypsin binding site. These results indicate that the kinetic stability of native bovine pancreatic trypsin inhibitor and its ability to function as a protease inhibitor are largely influenced by residues in two distinguishable regions of the folded protein.
Thirty-six normal subjects had to add two numbers ranging from 3 to 9 which were presented tachistoscopically. The two numbers were displayed either unilaterally to the left or right visual field, or bilaterally with one number to the left and one to the right visual field. They were represented as two word names, two dot clusters, or two bargraphs, or the two numbers were represented inconsistently in two different of these representations. The results showed that bilateral processing of a word and a bargraph was performed without visible interactions, and the hemispheres performed independently. When the display included a dot cluster, however, its processing (sequential vs. holistic) appeared to depend on the type of stimulus processed by the contralateral hemisphere, indicating strong interhemispheric interactions.
Subjects had to judge the semantic relation between two tachistoscopically presented German adjectives. In Exp. I, the two words were projected simultaneously, either both to the left visual field (i.e. to the right hemisphere, LVF-RH), or both to the right visual field (i.e. to the left hemisphere, RVF-LH), or one word to each visual field (i.e. to both hemispheres, EVF-BH). The results yielded a significantly higher performance in the condition EVF-BH than in the two unilateral conditions, without a significant difference between the latter two conditions. In Exp. II, the two words were shown successively. With bilateral presentation, a distinction was made as to whether the left visual field (EVF-BH-L) or the right visual field (EVF-BH-R) was stimulated first. The significantly highest performance was shown in conditions RVF-LH and EVF-BH-R compared with the condition EVF-BH-L, and the significantly poorest performance in the condition LVF-RH compared with the condition EVF-BH-L. The results provide evidence for (1) an intrahemispheric interference with simultaneous unilateral presentation, (2) a cooperative interhemispheric interaction with simultaneous bilateral presentation, and (3) an interhemispheric priming effect with successive bilateral presentation when the left hemisphere was stimulated first.
Fixation accuracy was related to perception of laterally presented consonants. Small left-eye fixation inaccuracy influenced perceptual performance of 8 men and 8 women.
Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field, or bilaterally with one element to the left and one to the right visual field. A distinction was made between the bilateral conditions as to whether the representation of the elements, printed and/or pictorial, included a high or low interstimulus and a high or low stimulus-hemisphere compatibility. Analysis indicated firstly a superiority of the left hemisphere for the naming of compound nouns in mixed print and pictorial representation. Secondly, the performance in the bilateral conditions was moderated by stimulus-hemisphere compatibility. In the process of interhemispheric integration stimulus-hemisphere compatibility proved more crucial than interstimulus compatibility. Analyses of errors further illustrated hemispheric behaviour.
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Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field or bilaterally with one element to each visual field. In the bilateral condition a distinction was made as to whether familiar or unfamiliar arrangement of the elements was used. Representation in print was compared with pictorial representation of the compound nouns. A right visual-field superiority was observed with printed representation, but no laterality effects with pictorial representation. Bilateral processing was superior to unilateral processing. Within the bilateral conditions, the familiar arrangement of the elements yielded a significantly better performance than unfamiliar arrangement. This difference can be explained by reading habits and/or by different styles of interhemispheric integration.
Normal subjects were asked to estimate the total surface of two black spots presented tachistoscopically, either both to the right or both to the left visual field, or bilaterally to either visual field. Performance was highest with unilateral left visual field presentation and lowest with bilateral presentation of the spots. Interhemispheric integration varied with the quantitative relation between the stimuli in the left and right visual fields. Errors may be due in part to an insufficient cooperation of the left hemisphere and/or to an ignorance of the right hemisphere and/or to an unreliable transfer by the cerebral commissures.
Under conditions of tachistoscopic stimulation normal subjects were presented visuospatial stimulus pairs which had to be integrated interhemispherically. The presence of a pronounced cognitive style improves the interhemispheric integration of this type of information. Two interpretations are discussed. The first explains the observed improvement with a qualitative division of labour, with one highly specialized and one just transmitting hemisphere, i.e., with hemispheric differentiation. The second emphasizes the relatively high capacity of the "subordinate" hemisphere in information processing, i.e., hemispheric similarity.
A case of bronchospasm during general anesthesia is presented in which atropine appeared to reverse bronchoconstriction, after high halothane concentrations, intratracheal lidocaine, and isoproterenol i.v. had all proved ineffective. This case illustrates a rational approach to the treatment of bronchospasm during anesthesia, based on determination of the most likely site of origin of bronchoconstriction within the tracheobronchial tree.
The injection of pregnant mice with 5 mg oestradiol dipropionate induced a high proportion of bilateral cryptorchidism in the male offspring. The ectopic testes were reduced in size and occupied one of three different positions in the abdomen: pararenal, paravesicular or inguinal. The seminal vesicles were found to be similarly reduced in size whereas the adrenals and pituitaries appeared to be unaffected. The total content of testosterone was reduced in the pararenally placed gonads but was not significantly different from that of the controls when the testes were in the inguinal region. The content of androstenedione was not significantly altered. The concentration of both hormones, however, was increased in all cases. Plasma testosterone levels were lower in all the offspring of treated mothers, especially in those with high ectopia.
In vivo mucus transport rates were studied in humans and donkeys by external measurement of the rate of clearance of insoluble monodisperse gamma-tagged aerosols. The influence of temperature, environmental toxicants and drugs which affect the autonomic nervous system were studied by determining the changes in clearance produced by them in individual subjects. In donkeys, increased pretest ambient temperature accelerated clearance by greater than 1.7%/ degrees C. Smoking 2-7 cigarettes reduced the duration of bronchial clearance by approximately 50% in both humans and donkeys. Donkeys were exposed to higher doses; with progressive slowing of tracheal and bronchial clearance for greater than 10 cigarettes. HCN, at concentrations up to 1230 ppm, produced only a mild transient slowing of clearance. In man, atropine slowed clearance, while the adrenergic stimulating drugs, isoproterenol and epinephrine, both accelerated it by greater than or equal to 4 times, as did isoproterenol when given subsequent to atropine. The cholinergic stimulating drug methacholine increased mucociliary transport in the the donkey. Administration of a tap water aerosol for 10-15 min in humans increased bronchial clearance rates by approximately 25%.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.