ABSTRACT
This report describes a specific technique which enables young music students to acquire basic motor skills essential for conducting. 18 adolescents ranging in age from 10 to 17 yr. were trained for one school year (about 9 months) to improve their manual motor performance. The systematic training, entitled preconducting, consisted of performing various repetitive combinations of certain continuous and punctuated, circular and linear movements, with the aim of making these skills as automatic as possible. The motor achievements were analyzed qualitatively and success depended more on motivation and daily practice than on age, sex, or handedness.
Subject(s)
Child Development , Music , Psychomotor Performance , Time Perception , Adolescent , Attention , Child , Female , Functional Laterality , Humans , Kinesthesis , Male , OrientationABSTRACT
Quantitative structure-activity relationships (QSAR) were derived for a number of 2,6-mono- and disubstituted purines. The derived equations relate the anticancer activity in murine Adenocarcinoma CA755 to the molar refractivity of substituents at position 2 and electron-withdrawing effects of substituents at position 6. A QSAR was also derived for the acute toxicity (LD50) of substituents at position 6. The results suggest that toxicity is relatively independent of the nature of the substituent.
Subject(s)
Adenocarcinoma/drug therapy , Antineoplastic Agents , Purines/pharmacology , Animals , Chemical Phenomena , Chemistry, Physical , Mice , Neoplasms, Experimental/drug therapy , Purines/toxicity , Structure-Activity RelationshipABSTRACT
A method for extracting LD50 values from antitumor test data is described. A quantitative structure--activity relationship (QSAR) for 7- and 10-substituted colchicines is presented. This correlation equation closely parallels that which had been derived earlier for potency. This result indicates that attempts to modify 7- and 10-substituted colchicines in order to decrease toxicity will likely produce a simultaneous decrease in potency. Ring A modified colchicines do not obey the potency and toxicity correlations. 4-Substituted colchicines appear promising in terms of decreased toxicity, greater ILS, and a broader therapeutic range.
Subject(s)
Colchicine/analogs & derivatives , Animals , Chemical Phenomena , Chemistry , Colchicine/toxicity , Lethal Dose 50 , Mice , Structure-Activity RelationshipABSTRACT
Linear free energy relationships were derived for several monosubstituted purines. The derived equations relate to the pKa to the Hammett constants sigma m and sigma p. A general linear free energy relationship was derived that permits calculation of the pKa of polysubstituted purines. The results suggest that correlation of biological data with standard parameters is feasible.
Subject(s)
Purines/pharmacology , Chemical Phenomena , Chemistry, Physical , Structure-Activity RelationshipABSTRACT
Changes in pH studied in vitro affected considerably the distribution of bupivacaine between the erythrocyte and incubation medium: in an acidic medium, the uptake of bupivacaine by erythrocytes was decreased. The acidosis induced in vivo in dogs' limbs during i.v. regional anaesthesia (IVRA) with bupivacaine was corrected by injecting sodium bicarbonate into the occluded limb. The concentration of bupivacaine in the cephalic vein was measured in dogs under. IVRA. After removal of the tourniquet, the drug concentration-time relationship showed a biexponential pattern of decline. Injection of sodium bicarbonate into the limb 10 min before the release of the tourniquet suppressed the rate at which the concentration of bupivacaine decreased during the second phase. This slower rate of drug release from the tissues may prolong residual analgesia.
