Application of an eremomycin-chiral stationary phase for the separation of DL-methionine using simulated moving bed technology.

Recently a new chiral stationary phase (CSP) was introduced, based on the immobilization of the macrocyclic glycopeptide eremomycin to epoxy-activated silica. The application of this new CSP to preparative enantioseparation using simulated moving bed (SMB) chromatography will be presented. MeOH-H(2)O (0.1M NaH(2)PO(4))=20/80 (v/v) was used as the mobile phase to separate the enantiomers of methionine. Successful separation was realized providing productivities around 15 g(product)/l(stat)/h for both l and d-methionine under nonlinear conditions. In such delicate continuous chromatographic separation processes, besides productivity, the long-term stability of the applied stationary phases is of importance. Column to column fluctuations were negligible and long-term stability of the preparative stationary phase was satisfactory according to the results of perturbation experiments performed before and after long-term SMB runs.

[Sorbents with immobilized glycopeptide antibiotics for separating optical isomers by high-performance liquid chromatography].

Chiral sorbents for HPLC separation of optical isomers carrying glycopeptide antibiotics (eremomycin or its eremosaminyl aglycon, ristomycin, or vancomycin) fixed onto the surface of silica gel have been synthesized. The patterns of the retention and separation of profen isomers and their dependence on the nature of the chiral selector and the eluant composition have been studied. The sorbents were shown to be highly enantiospecific in separating the isomers of alpha-amino-, alpha-hydroxy-, and alpha-methylphenylcarboxylic acids (profens).

New chiral stationary phase with macrocyclic glycopeptide antibiotic eremomycin chemically bonded to silica.

A new chiral stationary phase (CSP) was prepared by attachment of macrocyclic glycopeptide antibiotic eremomycin to the epoxy-activated silica under mild conditions. In contrast to CSP with immobilized vancomycin, which is a close structural analogue of eremomycin, the prepared CSP reveals high enantioselectivity for separation of amino acids enantiomers. It was demonstrated by the example of ristocetin A CSP that method of the immobilization of macrocyclic glycopeptide antibiotics affects remarkably the resulting enantioselectivity.

[Effectiveness of regional electric stimulation of the sympathetic ganglia in the treatment of suppurative wounds]. / Effektivnost' regionarnoi élektrostimuliatsii uzlov simpaticheskogo stvola v lechenii gnoinoi rany.

A new method of regional electrostimulation by means of influencing with low-intensity and frequency rectangular impulse current upon the sympathetic trunk in combination with a purulent wound treatment by the low-frequency ultrasound in the liquid media of tomicide contributes to significant enhancing the effectiveness of treatment of the patients, 2-fold shortening of a hydratation phase duration, rapid stabilization of general state of the patients. No side effects and complications were noted in performance of electrostimulation.

[The subcortical neuronal correlates of human assessment actions]. / Podkorkovye neironnye korreliaty otsenochnykh deistvii u cheloveka.

In patients with parkinsonism to whom in accordance with medical-diagnostic indices electrodes were implanted into the nuclei of thalamus and striopallidal system, impulse activity of neurones was recorded in tests with presentation of visual and acoustic stimuli. It has been shown that neurones of these structures, reacting by a change of discharges frequency in carrying out the assessing actions by man constitute a special class of neurones, spatially separated from those, connected with the organization of motor acts. The typical feature of neuronal reactions is a high degree of their value dependence on the level of attention. Neurones of the above structures reacts also during preparation of the assessing actions and fixation of their results in the short-term memory.