Search PubMed⌕ Search

Biomedical subjects

S V Kuznetsov

Publications and source records attributed to S V Kuznetsov.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Clinical and computer tomographic correlations in craniocerebral injuries: predicting outcome].

Statistic analysis of the results of examination of 114 patients with craniocerebral trauma disclosed clinico-computerized-tomographic signs which correlated with the outcomes of the disease. The possibilities of prognosticating the probable outcome of the trauma by mathematical statistic modeling were studied. Linear regressive models were constructed with consideration for only the clinical or for only the computerized-tomographic data or for both types. The informativeness of the model increased sharply (to 85%) when clinical and X-ray data were included in it. Linear discriminant models are marked by higher informative capacity (94%). It is shown that this trend in determining the severity of the trauma and planning adequate therapeutic measures is promising.

Brain Concussion↗
PubMedDate not supplied

[The N-cholinergic activation of the periodic activity of excitable structures in early postnatal ontogeny].

The influence of central N-cholinomimetics on the nature of respiratory rhythm has been studied on 0-16 day rats. It was established that lobeline injection (50 mg/kg) in the rats caused the replacement of background near-second respiratory rhythm by periodic respiration with the period of initiation of respiratory movement complexes of the order of 10-15 sec. Nicotine injection (5 mg/kg) caused less marked effect. On the basis of the present research and available data (the influence of N-cholinomimetics on the spontaneous motor activity and heart rhythm) in was inferred the direct participation of central N-cholinergic structures in reproduction of primary excitement rhythms including the rhythms with the period of 1 and 5-15 sec. The hypothesis on the unity of mechanisms forming the basis of generation of periodic excitement in different excitable structures has been put forward. It was proposed that cholinergic transmitter systems took part in the generation of primary rhythms.

Aging↗
PubMedDate not supplied

[Effectiveness of computed tomography in the diagnosis of otosclerosis].

Computer-aided tomography (CAT) is the most informative method for imaging the morphologic substrate of an otosclerotic process. In otospongiosis the tomograms show compact bone demineralization sites to the front of the vestibule fenestra (the fenestral form) or round the cochlear osseous capsule (the cochlear form); this latter form is better detectable by densitometry. During the stage of "mature" inactive otosclerosis the labyrynth fenestra are exposed to partial or complete obliteration. Combinations of active and inactive foci in the temporal bone pyramid are seen in 38% of cases. CAT helps accurately define the cause of stapedoplasty failure: anvil necrosis and the prosthesis subdislocation. CAT should be an obligatory diagnostic component in examinations of patients with sound conduction abnormalities.

Diagnosis, Differential↗
PubMedDate not supplied

[The possible mechanisms of the participation of the central cholinoreactive systems in regulating spontaneous motor activity in the early ontogeny of rats].

In experiments on 0-16-day rat puppies, studies have been made of the effects of activation of N-cholinoreceptors during injections of nicotine, inactivation of N-cholinoreceptors by ganglerone, as well as combination of ganglerone and DOPA on the spontaneous periodic motor activity. It was shown that activation of N-cholinoreceptors results in the reactions which were earlier described for newborn rats during injection of exogenous catecholamines, i.e. the increase in motor activity and the onset of rhythmic components in the latter. Experiments with spinalization and DOPA injection showed that the potentiating effect of nicotine is realized via the descending catecholaminergic systems. Therefore, central N-cholinoreactive systems are mature already in newborn animals exhibiting from the very first day of postnatal life modulatory effects on catecholaminergic neurones in the brain stem.

Aging↗
PubMedDate not supplied

[The ontogenetic characteristics of the coordination relationships between the hemicenters of the spinal motor pacemaker in rat pups].

In experiments on rat puppies of the first month of postnatal life, under the conditions of real motor behaviour (spontaneous periodic motor activity) and the evoked motor reactions (late prolonged motor discharges), studies have been made on the development of coordination relationships between antagonists of the same extremity and between homologous muscles of the hindlimbs. In was found that irrespectively of the early onset of reciprocal excitation of antagonists, the mechanisms of this activity are not mature. Maturation of bilateral coordinations takes place at later stages. It was noted that one of the hemicenters of the spinal motor pacemaker is capable of producing rhythmic or constant activity which is not related to the pattern of the activity in the other hemicenters of the pacemaker of the same extremity or hemicenters of pacemaker of homologous extremity. Administration of DOPA causes the disturbance of coordination relationships.

Aging↗
PubMedDate not supplied

[Decarboxylation of amino acids and peptides in a photoreaction with potassium ferricyanide at 77 K].

We have measured action spectra of formation of radicals in aliphatic amino acids and peptides by reaction of decarboxylation with excited potassium ferricyanide. Peptides are capable to the reaction under longwave absorbtion band excitation, whereas amino acids are stable under these conditions, and decarboxylation occur only under irradiations by lambda < 400 nm.

Amino Acid Sequence↗
PubMedDate not supplied

[Experience in using computed tomography in the diagnosis of diseases of the maxillofacial area].

Thirty patients aged 19 to 70 suffering from various diseases and injuries of maxillofacial organs and tissues (chronic odontogenic osteomyelitis, sinusitis, malignant and benign neoformations of the jaws and perimaxillary soft tissues, injuries to facial skull) were examined using computer-aided tomography. The method is described in detail, its potentialities in the diagnosis of the said diseases and injuries are demonstrated.

Adult↗
PubMedDate not supplied

[Population of triplet-excited states of tryptophanyls and tyrosyls in proteins].

The relative limiting concentrations of triplet excited states of tryptophan and tyrosine residues have been measured by the ESR method. The magnitude of limiting concentration of the tryptophan and tyrosine residues T1-states does not vary to fit their numbers in some proteins. A limitation on the concentration of T1-states is accounted for by the fact that in protein molecules there occurs the radiationless excitation energy transfer of chromophores on residues in the triplet state.

Electron Spin Resonance Spectroscopy↗
PubMedDate not supplied

[Computed tomography in the diagnosis of major stomatological diseases].

The paper summarizes the results of an examination of 32 patients aged 19 to 70 years who present with various dental diseases and maxillofacial soft injuries (chronic odontogenic maxillary osteomyelitis, osteoradionecrosis of the jaw, sinusitis, malignant and benign neoplasms of the jaw and perimaxillary soft tissues, facial injuries, etc.), by using computerized tomography (CT). It also describes a CT procedure, shows its potentialities in the diagnosis of major dental diseases and injuries to maxillofacial organs and tissues.

Adult↗
PubMedDate not supplied

[Variants in the arrangement of the tooth roots in the alveolar arches of the human jaws based on computed tomographic data].

Anatomo-topographic relationship of the teeth roots were studied by means of computer tomography (CT) on 44 passportized skulls with mandibles of people who died in the age of 20 to 52 years. Conseguently, sections of mandibles and maxillae were made out of these preparations and peculiarities of the teeth roots locations in alveolar arches were studied by craniometric method. Comparison of CT results and measurements of sections showed that CT is an informative method of assessment of the teeth roots anatomo-topographic relationship that permits to attain general true qualititative indexes, allowing to evaluate objectively the available variants of the alveolar arch structure and the teeth roots location without disturbance of the anatomic material integrity.

Adult↗
PubMedDate not supplied

[The dependence of spontaneous excitation processes on the nature of the metabolic activity in early postnatal ontogeny].

The spontaneous motor experiment expression and parameters (including a number of rhythms from semisecond to semiminute ones as well as parameters of respiratory rythm) dependence of the level of activity for one of the main metabolic pathways, pentose phosphate cycle, were studied in experiments on rat puppies 2-16 days old. With the aim of the action on this pathway the system administration of pentose phosphate cycle inhibitors, hydroquinone and amphetamine, was used. As a result of the study it has been found out that pentose phosphate cycle retardation produces an antilogarithmic effect on the spontaneous excitement processes. The structure of the periodic components for the motor activity changes in accordance with the used inhibitor. It has been shown than studied physiological rhythms are not the result of interaction of the concrete neuronal structures. They are reproduced (simulated) by these concrete neuronal structures depending on passing character of the certain metabolic reactions.

Aging↗
PubMedDate not supplied

[Mechanism of quenching of hematoporphyrin and mono-L-aspartyl chlorine e6 triplet states by metronidazole].

The quenching of the triplet state of hematopophyrin (3HP.) and mono-L-aspartyl chlorine e6, (3MACE.) by metrotlidazole (METRO) ground state, has been investigated in binary mixtures of water and aliphatic alcohol by means of 532 nm laser flash. In water, both 3HP. and 3MACE. quenched by METRO with at rate: kQw = 1.9 x 10(9) M-1.s-1. The quenching is accompanied by the appearance of a transient absorbance near 690 nm. This transient absorbance corresponds to the tetrapyrrole radical-cation formation in result of an electron transfer between 3HP. or 3MACE. and METRO. In neat alcohol, the electron transfer was not observed. In binary mixtures the quenching constant is reduced as the molar fraction of water is decreased. In water, the activation barrier of the quenching is 5.9 kcal/mol for HP and 3.9 kcal/mol for MACE. In going from water to water-alcohol mixtures the energy of activation is practically unchanged. Based on flash photolysis data, and analysis of absorption spectra of METRO we conclude that the electron-acceptor ability of metronidazole essentially depends on the intermolecular interaction with nearby solvent molecules. The mechanism of the quenching is discussed.

Electron Transport↗