Changes in the urine volatile metabolome throughout growth of transplanted hepatocarcinoma.

Trained detection dogs distinguish between urine samples from healthy organisms and organisms with malignant tumors, suggesting that the volatile urine metabolome contains information about tumor progression. The aim of this study was to determine whether the stage of tumor growth affects the chemical differences in the urine of mice and to what extent the "olfactory image of disease" perceived by dogs coincides with the "image of disease" recorded by the mass spectrometer. We used a novel laser ionization mass spectrometry method and propose a mass spectrometric analysis without detailed interpretation of the spectrum of volatile metabolomes in urine. The mass spectrometer we use works without sample preparation and registers volatile organic compounds in air at room temperature without changing the pH of the sample, i.e. under conditions similar to those in which dogs solve the same problem. The experimental cancer models were male BDF-f1 hybrid mice transplanted with hepatocarcinoma tissue, and similar mice transplanted with healthy liver tissue were used as controls. Our data show that both dogs and our proposed laser mass spectrometry method are able to detect both the entire spectrum of volatile organic compounds associated with the disease and minor changes in this spectrum during its course.

[Detection of Volatile Organic Compounds Associated with Hepatocellular Carcinoma by Macrosmatic Animals: Approaches to the Search for New Tumor Markers].

Macrosmatic animals (dogs and mice) have been proved to be able to distinguish between the urine or feces of mice with transplanted hepatocellular carcinoma and those of healthy mice by odor. The chemical composition of animal excreta was found to change with tumor growth; however, it is not clear yet if this results from tumor growth itself, inflammation, or immune response. We suggested that the use of the ability of macrosmatic animals to compare odor mixtures combined with mouse cancer models is a promising trend in the search for new tumor markers.

Whether radial receptive field organization of the fourth extrastriate crescent (area V4A) gives special advantage for analysis of the optic flow. Comparison with the first crescent (area V2).

Recently, elongated comet-shaped receptive fields were discovered in the fourth extrastriate crescent (area V4A) of cats and monkeys. It was shown that the long axes of these receptive fields were oriented radially toward the centre of the retina. Such unusual "radial" organization of this extrastriate area led to the assumption that these neurons may contribute to the analysis of optic flow. To investigate this assumption we recorded activity of neurons in the V4A of cats during real motion in depth toward or away from a stationary visual scene. Responses of neurons in area V4A were compared with activity of neurons in area V2 under similar conditions of stimulation. Area V2 is known to be sensitive to motion but does not have radial organization. It was found that a substantial number of visual neurons in both areas did not fire at all when cats were exposed to motion in depth. Nevertheless, neurons with selective activation to direction of motion in depth were identified, but comparable numbers were found in both areas studied. We conclude that radial organization of the fourth extrastriate crescent does not provide any special advantage for the analysis of optic flow information.

Two visual areas located in the middle suprasylvian gyrus (cytoarchitectonic field 7) of the cat's cortex.

Neuronal properties and topographic organization of the middle suprasylvian gyrus (cortical cytoarchitectonic field 7) were studied in three behaving cats with painlessly fixed heads. Two main neuronal types were found within this field. Type 1 neurons occupied the lateral part of the field and bordered representation of directionally selective neurons of the lateral suprasylvian visual area by vertical retinal meridian. Type 1 neurons had elongated and radially oriented receptive fields located in the lower part of contralateral visual field. Type 1 neurons preferred stimuli moving out or to the centre of gaze at a low or moderate speed, and many of them were depth selective. The responses were enhanced by attention, oriented to the presented stimulus. Medial part of the field 7 along the border with the area V3 was occupied by neurons with not elongated receptive fields (type 2). These neurons preferred moderate and high speeds of motion, and gratings of proper spatial frequency and orientation were effective stimuli for them. Border between representations of type 2 and type 1 neurons coincided with projection of horizontal retinal meridian. At the rostral and caudal borders of the field 7 abrupt changes of neuronal properties took place. Neurons which abutted field 7 anteriorly and posteriorly resembled hypercomplex cells and their small receptive fields were located in the central part of the visual field. Topographical considerations and receptive field properties allowed us to conclude that the medial part of the field 7 (included type 2 neurons) is functionally equivalent to the area V4 in the cortex of primates, while the lateral part (type 1 neurons) may correspond to the area V4T.

[The distribution of neurons in the caudate nucleus of the cat that respond to sensory stimulation and the organization of the topical projections]. / Raspredelenie v khvostatom iadre koshki neironov, otvechaiushchikh na sensornuiu stimuliatsiiu, i organizatsiia topicheskikh proektsii.

It has been shown in chronic experiments that cells responding to somatic and visual stimuli are unevenly distributed in the caudate nucleus of a cat and areas of high and low activity alternate. Representational maps of somatic and visual space in the caudate nucleus are not single. These data as well as those on the morphological heterogeneity of the caudate nucleus suggest the presence of multiple somato- and retinotopic maps projecting independently on striosome surfaces.

[The neuronal responses of the caudate nucleus in the cat to sensory stimulation]. / Otvety neironov khvostatogo iadra mozga koshki na sensornuiu stimuliatsiiu.

Responses of caudate neurons to a large variety of visual and other sensory stimuli were studied in alert cats. Sharp drops in the spontaneous activity of the unknown origin and differences in the activity level were revealed in adjacent parts of the caudate nucleus. The following types of neurons were recorded: neurons responding to visual stimulation; neurons responding to somatic stimulation; neurons responding to combined visual-somatic stimulation. The best response was observed to moving visual stimuli that attracted the animal's attention, alimentary objects specifically. The caudate nucleus of each hemisphere contained representation of both contra- and ipsilateral half of the animal body. Cell responses to sensory stimuli from the caudate nucleus have been compared with those from some cortical areas.

[The effects of the electrical microstimulation of the areas of the location of different cell types in the caudate nucleus]. / Effekty élektricheskoi mikrostimuliatsii zon raspolozheniia kletok razlichnykh tipov v khvostatom iadre.

Effects of electrostimulation of the caudate nucleus in cats were studied in chronic experiments. Position of electrolytic lesions resulting from stimulation was examined histologically with respect to the surrounding cell type. Stimulation of the caudate nucleus zones with cells responding to sensory stimuli induced cat's movement and corresponding lesions were situated around striosomes among large cells with long axons. Stimulation of "silent" zones (where we failed to record any neuronal activity) did not modify cat's behaviour, corresponding lesions were found inside striosomes in clusters of small and medium-size cells. Results obtained from this study confirm the previous conclusion that neurons which activity was recorded extracellularly in the caudate nucleus belong to large long-axon cells.

[Neurons with visual receptive fields independent of eye position in the caudal portion of the ventral wall of the cruciate sulcus of the cat cerebral cortex]. / Neirony s ne zavisimymi ot polozheniia glaz zritel'nymi retseptivnymi poliami v kaudal'nom otdele ventral'noi stenki krestovidnoi borozdy kory mozga koshki.

Neurons responding to tactile and visual stimulation have been found in alert behaving cats in the caudal part of the ventral bank of cruciate sulcus. Tactile receptive fields were located on the cat face mainly around the mouth. Visual stimuli (especially alimentary ones) were effective being presented near the tactile receptive field. It was found that these bimodal neurons (visual and somatosensory) are located in layer VI of the cortex and their visual responses demonstrate space constancy. The position of the visual receptive field of these neurons did not change after saccadic eyes displacements, but remained in-register with the tactile receptive field.