Representation of Faces in Longtailed Macaques (Macaca fascicularis)

The experiments described in this study were intended to increase our knowledge about social cognition in primates. Longtailed macaques (Macaca fascicularis) had to discriminate facial drawings of different emotional expressions. A new experimental approach was used. During the experimental sessions social interactions within the group were permitted, but the learning behaviour of individual monkeys was analysed. The procedure consisted of a simultaneous discrimination between four visual patterns under continuous reinforcement. It has implications not only for simple tasks of stimulus discrimination but also for complex problems of internal representations and visual communication. The monkeys learned quickly to discriminate faces of different emotional expressions. This discrimination ability was completely invariant with variations of colour, brightness, size, and rotation. Rotated and inverted faces were recognized perfectly. A preference test for particular features resulted in a graded estimation of particular facial components. Most important for face recognition was the outline, followed by the eye region and the mouth. An asymmetry in recognition of the left and right halves of the face was found. Further tests involving jumbled faces indicated that not only the presence of distinct facial cues but the specific relation of facial features is essential in recognizing faces. The experiment generally confirms that causal mechanisms of social cognition in non-human primates can be studied experimentally. The behavioural results are highly consistent with findings from neurophysiology and research with human subjects.     

NCI-H716 cells as a model for endocrine differentiation in colorectal cancer

In colonic neoplasms, endocrine differentiation is encountered not only in carcinoid tumors but also in adenocarcinomas, where endocrine cells may represent a distinct line of differentiation in the tumor. The significance of endocrine differentiation in colorectal cancer is not well established, partly because of the paucity of tumor cell lines which can serve as a model for studying endocrine differentiation. In this report we describe the properties of NCI-H716 cells, a cell line derived from a poorly differentiated adenocarcinoma of the caecum, under various in vitro conditions and as xenografts in athymic mice. Phenotypical properties were immunohistochemically assessed using a panel of differentiation related antibodies, and also by Northern blot analysis and by electron microscopy. Receptors for biogenic amines and peptide hormones were analyzed by ligand binding assay. These studies show that:

Inhibitory effects of ATP and other nucleotides on atrial natriuretic peptide (ANP) binding to R1-type ANP receptors in human neuroblastoma NB-OK-1 cell membranes.

ATP dose-dependently inhibited rat 125I-ANP-(99-126) binding to membranes from the human neuroblastoma cell line NB-OK-1 by increasing the KD value for the hormone without altering the Bmax value. After a 20 min preincubation with 37.5 pM 125I-ANP-(99-126) and 0.5 mM ATP, followed by the addition of 0.3 microM unlabelled ANP-(99-126), the proportion of rapidly dissociating receptors was 4-times higher than in the absence of ATP. The other nucleotides ADP, AMP, AMP-PNP, ATP gamma S, GTP, GDP, GMP, GMP-PNP and GTP gamma S were also inhibitory but with a lower potency and/or efficacy. Binding equilibrium data were satisfactorily simulated by a computer program based on partially competitive binding of ANP-(99-126) and the nucleotides, and this, together with the data on dissociation kinetics, strongly suggests that several nucleotides, when added at concentrations up to 1 mM, form a ternary ANP-receptor-nucleotide complex.     

Contrasting effects of PACAP and carbachol on [Ca]i and inositol phosphates in human neuroblastoma NB-OK-1 cells

The effects of PACAPs on [Ca²⁺]_i were compared to those of carbachol in human neuroblastoma NB-OK-1 cells. PACAP(1–27) and PACAP(1–38) increased [Ca²⁺]_i in a biphasic manner: a transient rise and a secondary plateau. The transient phase reflected the mobilization of [Ca²⁺]_i pool(s) via the inositol phosphate pathway. The modest sustained plateau required extracellular Ca²⁺. Carbachol also increased [Ca²⁺]_i in a biphasic manner, but it mobilized intracellular Ca²⁺ pool(s) with a higher efficacy than PACAPs, then greatly increased Ca²⁺ entry, this being accompanied by a more marked and prolonged elevation of IP₃ and IP₄ than with PACAPs. It is likely that cAMP-mediated phosphorylations due to PACAPs facilitated desensitization at the PACAP receptor-phospholipase C level, so that there was less Ca²⁺ handling through PACAP receptors than with muscarinic M₁ receptors.     

Phosphorylation of 3 particulate proteins in rat pancreatic acini in response to vasoactive intestinal peptide (VIP), secretin and cholecystokinin (CCK-8)

Rat pancreatic acini were preincubated with 0.4 mM 32Pi for 45 min at 37 degrees C, then exposed for 15 min to VIP, secretin or CCK-8. The incubation was terminated with a stop solution and a fraction rich in mitochondria and zymogen granules was separated from a microsome-rich fraction by differential centrifugation. After heating in the presence of SDS, beta-mercaptoethanol was added and the pattern of equivalent amounts of 32P-labelled proteins was examined by autoradiography of SDS-PAGE gels. VIP, secretin, and CCK-8 stimulated the phosphorylation of a Mr=33 K microsomal protein and that of two proteins of Mr=21 K and Mr=25 K mostly present in a fraction rich in mitochondria and zymogen granules. Stimulations were dose-dependent, the highest stimulant concentrations tested allowing 2- to 3-fold increases of phosphorylation over basal. When 1 nM CCK-8 was used simultaneously with 1 microM VIP, the cyclic AMP levels attained and the pattern of protein phosphorylation were similar to those obtained with VIP alone, and there was a potentiation of amylase secretion; when a supra-maximal 0.1 microM CCK-8 concentration was added, the VIP-induced elevation in cyclic AMP levels and the phosphorylation of the Mr=21 K and Mr=25 K proteins were partially antagonized, and no potentiation any more of secretion occurred. To conclude the in vitro phosphorylation of three particulate proteins (Mr=33 K, 25 K, and 21 K) was similarly increased in rat pancreatic acini in response to secretin and VIP (acting through cyclic AMP) and to CCK-8 (acting mostly through Ca2+).     

Experimental exophthalmos. Binding of thyrotropin and an exophthalmogenic factor derived from thyrotropin to retro-orbital tissue plasma membranes.

Biologically active preparations of 125I-thyrotropin, [3H]thyrotropin, and the [3H]exophthalmogenic factor derived from thyrotropin by partial pepsin digestion have been used to study the binding properties of the thyrotropin receptor on guinea pig retro-orbital tissue plasma membranes. In regard to the optimal conditions of binding, pH, buffer, salt concentrations, and temperature, these properties are the same as those described in any accompanying report concerning thyrotropin binding to bovine thyroid plasma membranes (Tate, R.L., Schwartz, H.I., Holmes, J.M., Kohn, L.D., and Winand, R.J. (1975) J. Biol. Chem. 250, 6509-6515). In addition, thyrotropin receptors on the retro-orbital tissue plasma membranes are similar to thyrotropin receptors on bovine thyroid plasma membranes in their apparent negative cooperativity and in their relative affinities for luteinizing hormone, the beta subunit of thyrotropin, and the alpha subunit of thyrotropin. In contrast, gamma-globulin from patients with malignant exophthalmos enhances binding when added to incubation mixtures containing the retro-orbital tissue plasma membranes but not when added to those containing thyroid plasma membranes. Normal gamma-globulin and gamma-globulin from Graves' disease patients without exophthalmos do not have this property. The gamma-globulin itself does not bind to the membrane except in the presence of thyrotropin or its exophthalmogenic factor derivative. Tryptic digestion of the retro-orbital tissue membranes releases specific thyrotropin and exophthalmogenic factor binding activity into the supernatant phase. Chromatography on Sephadex G-100 indicates that this trypsin-released receptor activity has a molecular weight of 75,000 or greater, rather than 15,000 to 30,000 for the trypsin-released receptor activity from bovine thyroid membranes (Tate, R.L., Schwartz, H.I., Holmes, J.M., Kohn, L.D., and Winand, R.J. (1975) J. Biol. Chem. 250, 6509-6515).     

Revisiting the use of Iprodione and Trichoderma in the integrated management of onion white rot

The biocontrol properties of Trichoderma species are well documented, but their effectiveness in antagonism of the problematic Sclerotium cepivorum, the causal agent of white rot in Allium species, appears limited with reports of significant control only relating to deliberately-mutated strains of Trichoderma. Our previous studies have indicated the possibility of using selected naturally-occurring strains of the antagonist in the suppression of other diseases; now in vitro and controlled environment in vivo studies have indicated that a degree of control of Onion White Rot is possible, and that the selected antagonist strains can be used in integrated treatments with Iprodione to good effect. The possible value of such treatments is considered in light of other approaches to the suppression of this continuing problem.     

A web server to locate periodicities in a sequence

Summary : FT is a tool written in C++, which implements the Fourier analysis method to locate periodicities in aminoacid or DNA sequences. It is provided for free public use on a WWW server with a Java interface. Availability : The server address is http://o2.db. uoa.gr/FT Contact : shamodr@atlas.uoa.gr      

Vascular Pattern Analysis for the Prediction of Clinical Behaviour in Pheochromocytomas and Paragangliomas

Pheochromocytomas (PCCs) are neuroendocrine tumors arising from chromaffin cells of the adrenal medulla. Related tumors that arise from the paraganglia outside the adrenal medulla are called paragangliomas (PGLs). PCC/PGLs are usually benign, but approximately 17% of these tumors are malignant, as defined by the development of metastases. Currently, there are no generally accepted markers for identifying a primary PCC or PGL as malignant. In 2002, Favier et al. described the use of vascular architecture for the distinction between benign and malignant primary PCC/PGLs. The aim of this study was to validate the use of vascular pattern analysis as a test for malignancy in a large series of primary PCC/PGLs. Six independent observers scored a series of 184 genetically well-characterized PCCs and PGLs for the CD34 immunolabeled vascular pattern and these findings were correlated to the clinical outcome. Tumors were scored as malignant if an irregular vascular pattern was observed, including vascular arcs, parallels and networks, while tumors with a regular pattern of short straight capillaries were scored as benign. Mean sensitivity and specificity of vascular architecture, as a predictor of malignancy was 59.7% and 72.9%, respectively. There was significant agreement between the 6 observers (mean κ = 0.796). Mean sensitivity of vascular pattern analysis was higher in tumors >5 cm (63.2%) and in genotype cluster 2 tumors (100%). In conclusion, vascular pattern analysis cannot be used in a stand-alone manner as a prognostic tool for the distinction between benign and malignant PCC, but could be used as an indicator of malignancy and might be a useful tool in combination with other morphological characteristics.