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Biomedical subjects

K Bucher

Publications and source records attributed to K Bucher.

At least 37 records · Page 2Linked to original sources
PubMed1986

Immunoblotting with monoclonal antibodies: importance of the blocking solution.

Four commonly used blocking agents, i.e., fetal calf serum, mammalian gelatin-Nonidet-P40, fish gelatin-Nonidet-P40, and defatted powdered milk were compared with respect to their efficiency to block the nonspecific background and to promote maximal immunoreactivity of monoclonal antibodies against human intestinal sucrase-isomaltase during immunoblotting. Two of five monoclonal antibodies were found to react with the electroblotted enzyme. However, one of the reacting antibodies gave optimal results with fish gelatin-Nonidet-P40 and the other with defatted powdered milk, while fetal calf serum lead to unacceptably high backgrounds. The results suggest that some of the difficulties encountered with monoclonal antibodies in immunoblotting may be due to inappropriate blocking conditions.

Antibodies, Monoclonal↗
PubMed1982

A longitudinal survey of side effects in a lithium clinic.

The cross-sectional and longitudinal patterns of lithium side effects were surveyed in a prospective 12-month study. The use of other psychotropic medication (antidepressants, neuroleptics) in addition to lithium was associated with a higher frequency of complaints. The presence of noneuthymic mood was not associated with changes in the incidence of side effects. Persistent side effects were not related to current age, age at onset of illness, severity of illness, or duration of lithium therapy. The chronicity of lithium therapy was not specifically associated with the presence or absence of any of the 23 side effects surveyed.

Age Factors↗
PubMed1981

Kybernetics of cardio-respiratory synchrony: characterization by modulating cardiac frequency.

The work concerns the special and particularly efficient kybernetic system which synchronizes respiratory and cardiac activities in rabbits. An experimental procedure is worked out to characterize its potentialities. It consists of an artificial, elective and continuous slowing down of cardiac frequency in left-side vagotomized animals. Whenever synchrony happens to exist - and this can be provided - such slowing down will tend to throw the two rhythms out of phase. The stronger the kybernetic system, then the more it should be able to outweigh such disturbing tendencies. The correlation between the speed of cardiac slowing and the number of synchronized breaths resisting such disturbances follows a hyperbolic course. Characteristics of this hyperbola offer a useful means of quantifying the kybernetic system.

Animals↗
PubMed1981

The topically irritant substance: essentials - bio-tests - predictions.

The paper describes a method for judging the irritative potentialities of substances; proposes a scoring system with which the 'ordinary' risks of many of the abundant marketed products for washing, cleaning etc. may be predicted without biological testing; discusses pharmacodynamic and pharmacokinetic aspects of topical irritancy and points to the problems of extrapolating from animal experiments to man.

Animals↗
PubMed1980

Frequency of new mutants among boys with Duchenne muscular dystrophy.

Haldane's rule states that one-third of the cases of an X-linked recessive lethal should represent new mutations. This rule is derived under the assumptions that there is equilibrium between mutation and selection, that mutation rates in ova and sperm are equal, and that heterozygous and homozygous normal women have the same fitness. To test this rule for Duchenne muscular dystrophy (DMD), we have examined the mothers of 55 boys with DMD (16 familial and 39 isolated cases) and classified them as carriers or noncarriers on the basis of measures of ribosomal protein synthesis (RPS). Of the 55 mothers, only nine (16.4%) are classified as noncarriers, a figure significantly different from the expected one-third. When the analysis is limited to the 39 mothers of isolated cases, 23.1% (9/39) are classified as noncarriers, still significantly different than expected under Haldane's rule. Violation of any of the assumptions under which Haldane's rule is derived could lead to deviations from the expected one-third new mutants. We find the most likely explantation to be a higher male than female mutation rate. This is supported also by the finding that maternal grandfathers in whom a mutation occurred had higher mean age at birth of the carrier daughter (33.7 +/- 1.6) than did the general population or intrapedigree controls (29.5 +/- 1.3).

Female↗
PubMed1979

Irritant actions of unphysiological pH values. A controlled procedure to test for topical irritancy.

The abdominal skin of juvenile white mice was used. Topical application was accomplished by intracutaneous injection. The solutions tested were thoroughly standardized. By using a special buffer system, a mixture of histidine glutamate and lysine glutamate, each pH value could be tested with the same buffer capacity. The pH values varied from pH 3 to pH 11, the solutions being always iso-osmolalic with plasma. Two criteria were used to judge the irritancy: (a) the edematous reaction for the first 6 h and (b) the macroscopic aspect after 24 h. A very special procedure enabled us to obtain objective numerical values for criterion (a). The results disclose that irritation becomes manifest at pH 4 and pH 10, becomes clear-cut with pH 3 and even more so with pH 11, and depends strongly on the buffer capacity employed. With two substances-amidosulfuric acid and (tri) sodium phosphate--it was exemplified how the procedure could be used to routinely screen for topical irritancy in an informative, inexpensive and decent manner.

Animals↗
PubMed1977

Cardio-respiratory synchronisms: synchrony with artificial circulation.

Rabbits with an artificial cerebral circulation can synchronize their respiratory rhythm with the pump stroke. There is evidence that the responsible kybernetic system is of a very elementary nature. The efficacy of the system is considerable and the experimental set-up as a whole offers itself as a model to search for drugs to increase the synchronizing potentialities.

Animals↗
PubMed1977

Quantifying drugs influence on cardio-respiratory synchronism.

The paper concerns the situation in which, for a considerable time, the onset of each respiratory cycle coincides with one and the same section of a cardiac cycle. A standardized procedure is described with which, in anesthetized rabbits, the potentiality of the biological mechanisms responsible for the phenomenon may be quantified. The procedure consists of progressively prolonging the cardiac cycles by selectively cooling the sinus node. Care is taken that during such procedure a situation is passed in which the respiratory cycles are a multiple of the cardiac cycles. The synchronizing kybernetic system, if any, must click in, then. As the prolonging of the cardiac cycles continues, the synchrony will get lost the sooner the weaker the potentialities of the kybernetic system and vice versa. Four drugs are tested as to their potential action on the kybernetic system. Nikethamide and methylphenidate tend to decrease its efficacy, allobarbital and benzoctamine tend to increase it, none of them, however, being conclusively effective.

Animals↗
PubMed1977

Cardio-respiratory synchronisms: synchrony with artificial circulation.

Rabbits with an artificial cerebral circulation can synchronize their respiratory rhythm with the pump stroke. There is evidence that the responsible kypernetic system is of a very elementary nature. The efficacy of the system is considerable and the experimental set-up as a whole offers itself as a model to search for drugs to increase the synchronizing potentialities.

Adaptation, Physiological↗
PubMed1976

Cryptopleurine--an inhibitor of translocation.

Ribosomes from a cryptopleurine-resistant mutant of yeast were analyzed to determine the subunit localization of the resistance alteration. As was previously reported (Grant, P., Sanchez, L., and Jiminez, A. (1974), J. Bacteriol. 120, 1308), in vitro resistance of polyphenylalanine synthesis to cryptopleurine was conferred by 40S subunits from the mutant. Binding studies with sensitive ribosomes were carried out in order to identify the subunit binding site for cryptopleurine. Over the range of concentrations which inhibited polyphenylalanine synthesis, binding was proportional to concentration, so that a unique binding site could not be detected. Furthermore, binding to isolated subunits was about fourfold greater than to 80S ribosomes, suggesting that non-specific binding was sensitive to the condition of the particles. Model systems were developed in order to determine which step of the elongation cycle was inhibited by cryptopleurine. Elongation factor 1 dependent binding of Phe-tRNA to ribosomes was not inhibited by cryptopleurine concentrations, which inhibited polyphenylalanine synthesis. The initial rate of N-acetylphenylalanylpuromycin formation was inhibited when 10(-5) M cryptopleurine was added prior to translocation, but not when added after. Little inhibition was observed in either case when mutant ribosomes were used. These results suggest that cryptopleurine primarily inhibited translocation.

Alkaloids↗
PubMed1976

Inspiration inhibiting effect of etorphine-derivatives.

The inspiration inhibiting vagal reflex as elicited in rabbits by tracheal occlusion in inspiratory position, is strongly increased by etorphine and its derivatives, the 19-isoamylderivative benig of outstanding activity.

Animals↗
PubMed1975

Some special respiratory effects of CO2 in pigeons.

Injections of CO2-gas have been made into an abdominal air-sac of pigeons. The resulting alterations of respiratory rate and of breathing efforts are dose-dependent and easily reproducible. The receptive zones for these effects do not seem to be located in the air-way system itself; they may be in the respiratory center. Some data provide further evidence for the assumption that the ventilation of the abdominal air-sacs is mainly one-directional, from outside to gas-exchange compartments. Panting increases the ventilation of the abdominal air-sacs.

Air Sacs↗