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Biomedical subjects

S V Kuznetsov

Publications and source records attributed to S V Kuznetsov.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[The effect of DOPA on segmental reflexes in rat pups].

In acute experiments on spinal 5-30-day rat puppies, studies have been made of the effect of DOPA (100 mg/kg intraperitoneally) on monosynaptic reflex in extensors (evaluated by parameters of H-reflex) as well as on polysynaptic segmentary reflexes. In 5-7-day animals, mainly the inhibitory effect was observed with a short phase of facilitation of monosynaptic reflex. From the 10th day, facilitatory effect of DOPA becomes a predominant one reaching maximum to the 16th day. Within first 16 days of postnatal life, DOPA exhibits facilitatory effect on short-latent polysynaptic reflexes and inhibits long-latent ones. To the 30th day, reactions which are typical of adult animals are observed: inhibition of short-latent and facilitation of long-latent polysynaptic discharges. The data obtained indicate that in early postnatal development the effect of DOPA on mono- and polysynaptic reflexes qualitatively differs from that in adult animals.

Aging↗
PubMedDate not supplied

[The late prolonged motor discharges during stimulation of the segmentary afferents in rat pups: the age-related characteristics].

In experiments on intact 5-30-day rat puppies under slight urethane narcosis, stimulation of contralateral afferents evoked late prolonged discharges in extensor muscles. Apart from these discharges, studies were also made on the outbursts of autogenic periodic motor activity. The specific feature of late discharges within the first 10 days is their extreme duration and the presence of rhythmic components. With respect to the pattern and temporal parameters, there is a strong similarity between late discharges and autogenic periodic motor activity which is typical of newborn rats. The decrease in the intensity of late discharges in ontogenesis is paralleled by inhibition of autogenic activity. The data obtained indicate that late discharges are genetically related to the ancient property of the central nervous system, i.e. the capacity to self-excitation and maintenance of active state.

Afferent Pathways↗
PubMedDate not supplied

[The late prolonged motor discharges during stimulation of the segmentary afferents in rat pups: the effect of L-DOPA].

In experiments on 5-30-day rat puppies, under slight urethane narcosis, studies have been made on the late prolonged discharges in extensor muscles evoked by stimulation of contralateral tibial nerve before and after injection of DOPA. Within the first 16 days, the drug completely abolished or significantly reduced late discharges, increasing the spontaneous motor activity. Beginning from the 16th day, periods of potentiation of late discharges were observed. The data obtained are discussed in relation to the development of mechanisms of control of the activity of spinal generators which are responsible for late discharges and spontaneous motor activity.

Afferent Pathways↗
PubMedDate not supplied

[The effect of L-DOPA on potentials of the dorsal surface of the spinal cord evoked by the stimulation of primary afferents in newborn rat pups].

In experiments on 5-30-day rat puppies, studies have been made of the effect of L-DOPA (100 mg/kg, intraperitoneally) on the activity of interneurones of the dorsal horn of the spinal cord as revealed from the parameters of potentials of the dorsal surface of the spinal cord. The specific pattern of reaction in 5-day animals is manifested in a succession of inhibitory inhibition and increase in the activity of neurones monosynaptically activated by low-threshold afferents. Both the amplitude and duration of polysynaptic components of the potentials of the dorsal surface are rather high. From the 7th day, deep and stable inhibition is observed which is accompanied by a decrease in the amplitude of all components of the potential of the dorsal surface. At later stages of ontogenesis, a decrease is observed in the inhibitory effect of L-DOPA on the activity of interneurones which monosynaptically contact with low- and especially high-threshold afferents; in contrast to earlier stages, but similar to adult animals, evident inhibition was revealed in the activity of interneurones which have polysynaptic contacts with high-threshold afferents and afferents of flexor reflex. Thus, within the first weeks of postnatal life, basic qualitative changes are observed in the pattern of the reaction of interneurones of the dorsal horn to exogenic catecholamines.

Aging↗
PubMedDate not supplied

[Computerized tomography: features of roentgeno-anatomy of the temporal bone].

Normal X-ray and computed-tomography anatomy of the temporal bone are presented. It is indicated that computed tomography has certain advantages over routine X-ray methods because it allows simultaneous visualization of bone structures and soft tissues of the temporal bone. The anatomical picture of every compartment of the tympanic cavity as seen in CT and visual features of different structures of the temporal bone as related to the tomographic section plane are described in detail. In addition to the clinical advantages, CT is superior to standard X-ray methods in terms of radiation safety of the lens. CT data help to understand correctly the nature of pathological formations in the temporal bone and to apply adequate and effective therapeutic measures.

Ear, Middle↗
PubMedDate not supplied

[Ultrastructural changes in the hepatocytes in chronic delta infection].

Electron microscopy and morphometry were used to study liver biopsies from 22 patients with chronic active hepatitis. On the basis of clinico-morphological data 9 patients were diagnosed as having chronic active delta hepatitis and 13 patients chronic active hepatitis B. The studies indicate more marked involvement of hepatocytes in chronic delta hepatitis as compared with chronic hepatitis of HB virus etiology. Morphometric methods allow quantitation of the degree of manifestations of hepatocyte ultrastructural changes in the two groups of patients.

Biopsy↗