Topochemistry. Part XXXIX. The Solid-state Photochemistry of some 2′-Nitrochalcones

It is shown that the specific pathway of a complex photochemical reaction in the solid state is governed by the molecular conformation and its retention, and by the molecular packing. 2′-Nitrochalcone and those of its derivatives which are isomorphous with it display the s-trans conformation in the solid state and yield indigos upon irradiation. However, this conformation is not sufficient to ensure photoreactivity: thus the s-trans-4-bromo-derivative does not yield indigo. The same derivative in the s-cis conformation (in a second crystal form) has a crystal structure similar to that of the parent compound, and also does not yield indigo.     

Analytical techniques for cell fractions. XXIII. A stable thermal gradient device for heat denaturation studies on proteins

The ISO-DALT two-dimensional electrophoretic system (1,2), based on the method of O'Farrell (3), is capable of performing large numbers of analysis on complex mixtures of proteins. However, both separations employed are carried out under dissociating or denaturing conditions and no enzyme activities are readily observable in the analyzed proteins. In order to identify the spots corresponding to particular enzymes, it is therefore necessary to employ some nondestructive resolving technique first and as a second step to perform both enzyme and two-dimensional electrophoretic analyses on the fractions generated. By correlating enzyme activity with intensity of various spots on the two-dimensional gels throughout the series of initial fractions, identifications, can be made. This approach, unlike the more direct immunoprecipitation methods (4), requires the running of large numbers of enzyme analyses and two-dimensional gels and some convenient initial resolving procedure. Convenient and rapid techniques for the analyses (5,6) and gels (1,2) have been described previously in this series and elsewhere. This paper deals with the use of selective denaturation in a temperature gradient as an initial resolving procedure and describes a simple thermal gradient device for generating such a gradient.     

The effect of euthyscope- and occlusion therapy in cases of convergent strabismus. Comparative, prospective examinations (author''s transl)]

1. 63 children with strabismus and amblyopia (average age 7 years) were chosen at random to be treated either with occlusion or with the Euthyscope followed by occlusion. No significant difference was apparent after comparison of both forms of treatment. 2. Six more children were occluded for several months without success and were then treated for two months with the Euthyscope followed by further occlusion. In four of these cases pleoptic treatment proved to be temporarily successful. 3. In addition, 14 children with microstrabismus and amblyopia, and 17 children with amblyopia ex anisometropia showed a distinct improvement of the visual aciuty after occlusion. An 18-year-old patient with microstrabismic amblyopia achieved normal visual acuity. 4. Euthyscope treatment was used in amblyopic patients who had lost their good eye. In the case of an 18-year-old patient the distant visual acuity increased to 0.6. The increase in the near vision and the speed of reading continued to improve for several years. 5. Papilla-Macula-Relationship: 47 amblyopes were compared with 8 anisometropic and 16 microstrabismic patients as well as with 32 normal subjects. In these groups no significant difference in the papilla-maculadistance was apparent. 6. Refraction: In amblyopic eyes there were no significant refractive errors between fixing and non-fixing eyes. Conversely, in patients with microstrabismus and those with anisometropic a significant difference was found.     

Effects of dextran, gelatine and homologous plasma on circulation in shock caused by severe anemia in the dog

Irreversible shock is produced in 28 anaesthetized mongrel dogs by withdrawal of erythrocytes and substitution by dextran, gelatine or plasma to an average Hb of 4.5g%. In contrast to other shock models cardiac output and perfusion pressure are not decreased by this preparation. In order to maintain arterial blood pressue above 90 mm Hg significantly more gelatine than dextran or serum has to be infused. There is no difference in hemodynamic responses after treatment with dextran or gelatine respectively. Both groups treated with colloidal solutions have the same survival rate of 38%. In the serum substituted dogs, however,survival rate is significantly greater (83%). Very likely this is due to a greater buffer capacity preventing severe acidosis, which is observed in the animals treated with colloidal solutions.     

Effect of psychopharmaceutic agents on cortical potentials and long-lasting post-tetanic changes in excitability released through stimulation of the dental pulp

Short-time tetanic stimulation of the tooth pulp with square pulses affords, depending on the stimulation parameters selected, a long-lasting facilitation in the response of subsequently applied test stimuli in the sensomotor cortex of rabbits. The benzodiazepin derivatives, chlorodiazepoxide, nitrazepam (10 mg/kg i.p.) and clonazepam (1 mg/kg i.p.) caused suppression of posttetanic facilitation with partly different influences on cortical potentials following individual stimulation. Meprobamate (200 mg/kg i.p.) had no effect on the processes of posttetanic facilitation, while the amplitudes of sensomotor potentials showed a long-lasting reduction on single stimulation. Chloropromazine (2 mg/kg i.p.) showed a rapid and transient inhibition of posttetanic facilitation and reduced the amplitudes of evoked potentials following single stimulation.     

Long-acting narcotic antagonist complexes

We evaluated the ability of close to 100 organic acids to form water-soluble salts with methadone, cyclazocine, naloxone, naltrexone and, more recently, diprenorphine. About half the acids yielded insoluble salts. Polybasic acids affording insoluble salts were evaluated for their ability to form drug:acid:metal complexes with the polyvalent metal ions, Zn++, Al+++, Mg++ and Ca++. Optimum conditions for forming complexes have been developed and the consistency of their composition has been established. Salts were analyzed spectrophotometrically for drug content, and complexes were analyzed for drug and metal content. The in vitro degree of dissociation at equilibrium was measured for the preparations suspended in a simulated physiological buffer, pH 7.3. Preparations of the narcotic antagonist drugs showing relatively low degrees of dissociation in vitro, since it early appeared that a high degree of dissociation contraindicated a prolonged duration of pharmacological action, were evaluated in mice after intramuscular administration at several dose levels by the mouse tail-flick test for the potency and duration of their morphine antagonist activity. Our most promising preparations to date, showing the most prolonged durations of action without evidence of gross toxicity, are naltrexone zinc tannate and naltrexone aluminum tannate. These are undergoing detailed evaluation as potential clinical candidates. Thus far, the most useful of several dosage forms studied is a suspension in an aluminum monostearate gel.     

Closed-loop control of stochastic non-linear systems

A new approach for optimum control of stochastic non-linear systems is developed from practical engineering assumptions. Systems amenable to this new approach include optimum guidance and navigation systems for space and terrestrial vehicles, optimum closed-loop process controllers and optimum controllers for systems with unknown parameters. The classical quadratic synthesis approach—optimization of a deterministic cost and perturbation estimation and control about that solution—is shown to give 24 per cent more cost and 97 per cent more mean-squared terminal error than the combined optimization approach presented for a sample problem involving control of a first-order system with an unknown time constant. A similar improvement in terminal error is shown for an atmospheric entry problem. Furthermore, the optimum controller automatically designs the best controller to minimize the effects of the unknown parameter without artificial augmentation of the cost function as is done in the sensitivity theory approach. The solution is obtained by expansion of the cost function in a power series around a deterministic trajectory with the assumption of linear perturbation estimation and control about that trajectory. Optimization of the expanded cost function gives necessary conditions dependent on the covariance matrices and the deterministic portion of the cost. When the necessary conditions are solved, a set of open-loop controls, perturbation controller gains, and perturbation estimator gains are obtained that can be precomputed and implemented into the system.