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Notes: Summary We have analysed, in the awake monkey (Macaca sylvana) the functional properties of 489 neurones in the prelunate visual area (PVA, largely corresponding to V4). PVA has a coarse retinotopic organization with the lower quadrant of the visual field represented along the prelunate gyrus. The visual periphery is located medio-dorsally, the central visual field laterally near (and within?) the inferior occipital sulcus and the upper quadrant latero-ventrally. The vertical meridian runs caudally within the lunate sulcus, the horizontal meridian crosses the prelunate gyrus and continues into the superior temporal sulcus. Receptive field diameters of neurones vary between 1° and 10° with increase towards the visual periphery, but are strictly confined to the contralateral visual field. 28% of the neurones showed spectral sensitivity. About half of these cells had strong spectral opponency, the other half showed only weak opponency with broader spectral response curves. 11 cells (2%) showed striking centre/surround interactions with inhibition, disinhibition or occlusion of the two mechanisms, and different spectral response ranges of the centre and the surround, respectively. 43% of the prelunate cells were responsive to various spatial features without spectral sensitivity. We distinguished on- and off-center cells (2%), direction and movement sensitive cells (10%) and cells sensitive to gratings of parallel lines within a limited range of orientations (about 10%). A special group were cells which responded strongly to stimuli which contained many contrasts (textures without specific orientations and without regular spatial arrangements) (9%). Many of these cells were specifically responsive to variations of the internal structure of such stimuli. 3% of the cells were strongly activated in connection with behaviour: 11 neurones discharged strongly when the monkey looked attentively at a human face or when he responded with facial expressions to a threatening expression of a person. Photographs of faces were not effective. Some neurones (1%) were activated in connection with eye movement. These neurones were found in the lateral part of the prelunate gyrus. Neurones with spectral or non-spectral properties were clustered within small, irregularly shaped patches of 1–4 mm diameter. It is concluded that the prelunate visual cortex, which we consider as part of area 19, is not just a “colour area”, but represents various features of the visual environment (including colour, luminance, movement, texture and behavioral significance), and relates them — through its subcortical and cortical outputs — to behaviour. The various visual cortical areas may be seen as a cooperative of several connections between visual input and behaviour output rather than as links in a hierarchical chain of perceptual and cognitive representations.

Notes: Abstract Two weeks after the inoculation of 1.5 × 105 9L glioma cells into the rat brain, the uptake of radiolabelled drugs into the brain and the experimental 9L glioma during the first cerebral circulation was measured with a liquid scintillation counter and analyzed by the method of Oldendorf (1970). The expression of P-glycoprotein, which is known to be associated with the efflux of drugs, was also studied, using anti-P-glycoprotein monoclonal antibody, C-219. Furthermore, the ultrastructure of brain capillaries, tumor vessels, and glioma cells was studied by conventional and immunoelectron microscopy. Sucrose (control), the transport of which through the blood-brain barrier is known to be negligible, accumulated to fivefold higher levels in the tumor than in normal brain. Ranimustine (MCNU), 5-fluorouracil (5-FU), and doxorubicin showed little accumulation in the normal brain, whereas nimustine (ACNU) showed an increased accumulation. MCNU and doxorubicin showed negligible accumulation in the glioma cells despite diffusion into the tumor interstitial space. In contrast, ACNU and 5-FU showed an increased accumulation in tumor cells. The accumulation of 5-FU in the cultured 9L glioma cells was decreased by ATP inhibitors or by low temperature. Although both brain capillary endothelial cells and glioma cell membrane were immunohisto-chemically positive for P-glycoprotein, the tumor vasculature showed low expression of P-glycoprotein. The endothelial cells of tumor vessels ultrastructurally showed increased fenestrations, swelling, and disrupted junctions. Accordingly, it is suggested that hydrophobic drugs such as doxorubicin, being pumped out by P-glycoprotein, do not accumulate in 9L glioma cells as do other lipophilic drugs such as ACNU, or drugs such as 5-FU, which accumulate by a carrier-mediated mechanism.

Notes: Summary We have recorded from 661 single neurons in the foveal and parafoveal region of area 17 of the awake trained macaque monkey. The functional properties of 538 cells were investigated in detail, with flashed and moving stimuli of varying form and colour. Irrespective of their functional properties such determined, each neuron was also tested with a 2×2° square of various luminance and colour. This was done in order to get an idea how such a simple stimulus is represented by the activities of neurons in area 17. Most of the neurons showed response preference for certain aspects of visual stimuli. We have distinguished the following functional groups: 1. Sustained spectrally selective neurons (21%). These cells respond with tonic discharges to light of their optimal wavelength, and their spectral selectivity corresponded to that of opponent parvocellular cells of the lateral geniculate body. 44% of these cells were excited selectively by long, 23% by middle and 33% by short wavelength light. When slowly moving the 2×2° square of their preferred wavelength across the receptive field, discharge rate remained elevated, as long as the stimulus covered the RF and with little contour enhancement. The majority of the sustained spectrally sensitive cells responded equally well or better to large than to small (1.0°) stimuli, 17.5% were less activated and few of them completely suppressed by larger stimuli. Such cells were poorly orientation sensitive. Only three cells with weak double opponency could be identified (2.7% of this group). 2. Broadband contour (18%) and 3. Panchromatic contour cells (41%). Most neurons of these two groups were strongly activated by spots (1°) centered on their RF. They showed a short phasic response to contrast borders and most of them responded to luminance contrasts, including contrast reversal and colour contrasts equated for luminance. The broadband contour cells showed a slight wavelength preference with only weak or without any opponent suppression, the panchromatic contour neurons did not show any wavelength selectivity. Most showed orientation or direction sensitivity, but very sharp orientation selectivity was less common in spectrally biassed than in panchromatic contour cells (see Fig. 11). They responded tonically to gratings of optimal orientation and therefore may play a role also for cortical representation of textures. 22% of a restricted sample of panchromatic contour cells (or 9% of all cells) were hypercomplex. 4. Light inhibited cells. 7% of all cells were inhibited by small and large light stimuli of any wavelength centered on their receptive field, and were tonically activated by darkspots or contrasts, comparable to the light inhibited cells of the parvocellular lateral geniculate layers. 5. Neurons without consistant visual responses (11%). These neurons could not be driven by any of our visual stimuli. They were usually found in the upper cortical layers. 61 cells were tested for monocular vs. binocular input. 96% were excited from both eyes with various degrees of ocular dominance, but more binocular cells were contralaterally than ipsilaterally dominated (43 and 22%, respectively). Binocular cells showed qualitatively the same functional properties from both eyes, including spectral selectivity if there was any. Binocular summation varied between cells and was in the average 0.7, probably due to interocular inhibition. Some columnar grouping of cells with similar response properties as defined above was found in vertical penetrations, but “mixed” penetrations were common. Spectrally selective cells with the same spectral preference or light inhibited cells often were found close to each other and in the same penetration, but also often mixed with other cells excited by parvocellular input. This spatial organization is consistant with a columnar segregation of cells excited predominantly by one type of parvocellular afferents on the one hand, and contour cells with a mixed excitatory and a strong inhibitory input, on the other hand, but also indicates a considerable mixing and overlap of functional inputs into any axis perpendicular to the cortical surface. The functional organization of area 17 is compared with that of the lateral geniculate body and the prelunate visual area (V4) as investigated with the same methods and by the same laboratory.

Notes: Summary The ontogenetic development of catecholamine (CA)-and LHRH-containing nerve endings in the median eminence of the rat was investigated by combining fluorescence histochemistry and immunohistochemistry in the same tissue section. LHRH-terminals appeared earlier than CA-terminals and were already detectable in the lateral part of the external layer of the central ME on the first day after birth. CA-nerve endings were first seen in a corresponding region of the ME on the seventh postnatal day. At this stage both types of terminals showed the earliest manifestation of a correlative pattern of their distribution. Subsequently the development of both types of nerve endings proceeded rapidly, and at 14 days their distribution pattern corresponded to that in adult animals. The authors conclude that at this stage the CA-neurons play a constant and significant role in the release of LHRH into the portal capillaries. The correlation between both types of nerve endings and the ontogenetic development of the capillary plexuses of the hypophysial portal system is discussed.

Notes: Summary The localization of mitochondrial (m-) and cytosolic (c-) aspartate aminotransferase (AAT) was examined in the vestibular ganglion neurons and sensory cells in the vestibular end-organs of rats by an indirect immunohistochemical method using antibodies specific for m- and c-AAT. Neurons in the vestibular ganglion were stained by both m- and c-AAT antibodies, but the vestibular sensory cells exhibited only m-AAT-like immunoreactivity and were not labeled by c-AAT. These findings suggested that aspartate is a neurotransmitter in the hair cells of the vestibular end-organs.

Notes: A new thermal conduction model is proposed for a polymer system filled with a mixture of several types of particles. Predicted values by the new model are compared with experimental data. The model is derived by extending a model that was previously proposed for a two-phase system. The following equation is derived from the new model: log λ = V · (X2 · C2 · log λ2 + X3 · C3 · log λ3 + (1 - V) log (C1 · λ1. When the thermal conductivities of polymer and particles (λ1, λ2, λ3, …) and a mixing ratio of particles (X2, X3, …) are known, thermal conductivity of the filled polymer (λ) with several types of particles can be estimated from the equation, with any volume content of particles (V). Furthermore, from each polymer-filler composite (two-phase system) data, the thermal conductivity of a composite filled with different filler particles can be estimated.

Notes: Pantoprazole (PAN) is a proton pump inhibitor that is administered as a racemic mixture. The pharmacokinetics of PAN enantiomers were investigated in extensive metabolizers (EMs) and apparent poor metabolizers (PMs) of PAN who received a single 40, 60, or 80 mg oral dose of racemic PAN as enteric-coated formulation. In the EMs, the serum concentrations of (-)-PAN were slightly higher than those of (+)-PAN at each dose level. The (+)/(-) ratios for the area under the concentration-time curve (AUC) and the half-life were 0.58-0.89 and 0.62-0.88, respectively. In the PMs, the serum concentrations of both enantiomers were much higher than those in the EMs at each dose level and significant differences in pharmacokinetics of (+)- and (-)-PAN were observed. The half-lives for (+)-PAN were 2.67-3.77 times longer than those for (-)-PAN. The AUCs for (+)-PAN were 2.65-3.45 times greater than those for (-)-PAN. Therefore, the metabolism of (+)-PAN is impaired to a greater extent than (-)-PAN in the PMs, which resulted in the stereoselective disposition of PAN in the PMs. It has been suggested that the EMs and the PMs of PAN could be differentiated by determining the (+)/(-) enantiomer ratio in serum at one time point, possibly 2-6 h after oral dosing, because the (+)/(-) enantiomer ratios in the PMs were opposite those in the EM subjects. Chirality 9:17-21, 1997 © 1997 Wiley-Liss, Inc.

Notes: A novel optical biosensor for homogeneous immunoassay has been developed on the basis of the finding that electrochemical luminescence of pyrene-labelled antigen is extremely inhibited by immunochemical complexation. Electrochemical luminescence homogeneous immunoassay for human serum albumin (HSA), as a model analyte, was performed with a platinum plate electrode which was located in the vicinity of an optical fibre tip. HSA was determined in the concentration range of 3-25 × 10-6 mol/I.To improve electrochemical luminescence measurement an optical fibre electrode has been developed by fabricating a transparent platinum film on the top of an optical fibre. The minimum detectable limit of luminol was 10-11 mol/l with the optical fibre electrode. Luminol was applied as a label for homogeneous immunoassay.

Notes: Polyethylene and polystyrene composites filled with high-volume content of filler particles (quartz or Al2O3) were prepared by ordinary melt-casting method to effectively increase the thermal conductivity. The result, however, suggested that fractional void volume cssentially occupied by filler particles is left unfilled when high or super-high content of filler is used. After investigating the relation between the mixing ratio of different sized filler particles and the fractional voidage under various compression intensities, a mixture of filler was found to give minimum fractional voidage. Polymers filled with such an optimum mixture of fillers for minimum fractional voidage were then prepared under compression. Thus, expected monotonous increases in thermal conductivity in the wide range from low to super-high filler content were obtained. Further, it was confirmed that a predictive model proposed by us agreed quite satisfactorily with the experimental data in comparison with many other models.