An annotated bibliography on the origin and descent of domestic mammals, [by] Shimon Angress and Charles A. Reed.

v.54:no.1(1962)

Agate : physical properties and origin, archaeology and folk-lore / By Oliver C. Farrington, Curator of Geology, [and] Berthold Laufer, Curator of Anthropology.

no.8(1927)

A Model of ethnic conflict

We present a model of conflict, in which discriminatory government policy or social intolerance is responsive to various forms of ethnic activism, including violence. It is this perceived responsiveness -captured by the probability that the government gives in and accepts a proponed change in ethnic policy- that induces individuals to mobilize in support for their cause. Yet, mobilization is costly and demonstrators have to be compensated accordingly. Individuals have to weigh their ethnic radicalism with their material well-being to determine the size of their money contribution to the cause. Our main results are: (i) a one-sided increase in radicalism or in population size increases conflict; (ii) a one-sided increase in income has ambiguous effects depending on the elasticity of contributions to income; (iii) an increase in within-group inequality increases conflict; and (iv) an increase in the correlation between ethnic radicalism and inequality also increases conflict.

The vertical dispersión of Anopheles (Kerteszia) cruzi in a forest in southern Brazil suggests that human cases of malaria of simian origin might be expected

By staining females of Anopheles cruzi with fluorescent coloured powders in a forest in the State of Santa Catarina, we showed that they move from canopy to ground and vice-versa to feed. This suggests that in areas where this mosquito is a vector of human and simian malarias sporadic infections of man with monkey plasmodia might be expected.

Cortical origin of functional recovery in the somatosensory cortex of the adult mouse after thalamic lesion

Résumé L'accident vasculaire cérébral sensoriel pur est un des syndromes lacunaires, dû à l'occlusion de petits vaisseaux cérébraux, souvent dans le cadre d'une lésion intéressant le noyau ventro-caudal du thalamus. Il produit un hémisyndrome sensitif pur, et parfois un syndrome douloureux se développe à distance de l'événement aigu. Afin d'étudier la récupération fonctionnelle dans le cortex somatosensoriel (SI) après une telle lésion dans le thalamus, un modèle de lésion excitotoxique a été développé dans le système somatosensoriel de la souris adulte, caractérisé par la présence de formations cytoarchitectoniques dans SI appelées "tonneaux". Chacun de ces tonneaux correspond à la représentation corticale d'une vibrisse du museau. L'activité métabolique a été mesurée dans SI à différents intervalles après la lésion, à l'aide de déoxyglucose marqué radioactivement. Dans les deux premiers jours suivant celle-ci, l'activité métabolique diminue de manière importante dans toutes les couches corticales, avec une atteinte plus marquée dans la couche IV, principale projection des axones thalamo-corticaux. Une récupération de l'activité métabolique se produit ensuite, d'autant plus marquée que le délai après la lésion est grand. Cette récupération s'observe dans toutes les couches coticales, les couches I et Vb récupérant plus rapidement que les couches II, III, IV, Va et VI. Cinq semaines après la lésion, l'absence des vibrisses correspondant à la partie déafférentée de SI diminue l'activité métabolique corticale de 32% et démontre l'activation par la périphérie de cette partie de l'écorce, malgré la perte des axones thalamo-corticaux provenant du noyau ventro-caudal. Des expériences de traçage rétrograde ont montré une augmentation des projections intracorticales sur la partie déafférentée de l'écorce, en particulier de longue distance, ainsi que des projections interhémisphériques, mais n'ont pas permis de mettre en évidence de nouvelle projection thalamique, indiquant une origine corticale à la récupération fonctionnelle observée. Abstract To study the degree and time course of the functional recovery in the somatosensory cortex (SI) after an excitotoxic lesion in the adult mouse thalamus, metabolic activity was determined in SI at various times points post lesion. Immediately after the lesion, metabolic activity in the thalamically deafferented part of SI was at its lowest value but increased progressively at subsequent time points. This was seen in all cortical layers, however, layers I and Vb recover more rapidly than layers II, III, IV, Va and VI. Removal of the mystacial whiskers corresponding to the deafferented area, 5 weeks after cortical recovery, produced a subsequent 32% drop in metabolic activity, demonstrating peripheral sensory activation of this part of the cortex. Tracing experiments revealed that the deafferented cortex did not receive a novel thalamic input, but cortico-cortical and contralateral barrel cortex projections to this area were reinforced. We conclude that the cortical functional recovery after a thalamic lesion is, at least partially, due to modified cortico-cortical and callosal projections to the deafferented cortical area.

Genetics: biased transmission of genomes according to parents of origin.

A new study shows that wood ant queens selectively pass the maternally-inherited half of their genome to their daughters and the paternally-inherited half to their sons. This system, which most likely evolved from ancestral hybridization, creates distinct genetic lineages.

Evaluation of tumour vascularisation in two rat sarcoma models for studying isolated lung perfusion. Injection route determines the origin of tumour vessels.

Isolated cytostatic lung perfusion (ILP) is an attractive technique allowing delivery of a high-dose of cytostatic agents to the lungs while limiting systemic toxicity. In developing a rat model of ILP, we have analysed the effect of the route of tumour cell injection on the source of tumour vessels. Pulmonary sarcomas were established by injecting a sarcoma cell suspension either by the intravenous (i.v.) route or directly into the lung parenchyma. Ink perfusion through either pulmonary artery (PA) or bronchial arteries (BA) was performed and the characteristics of the tumour deposits defined. i.v. and direct injection methods induced pulmonary sarcoma nodules, with similar histological features. The intraparenchymal injection of tumour cells resulted in more reliable and reproducible tumour growth and was associated with a longer survival of the animals. i.v. injected tumours developed a PA-derived vascular tree whereas directly injected tumours developed a BA-derived vasculature.

Metabolic origin of insulin resistance in obesity with and without type 2 (non-insulin-dependent) diabetes mellitus.

A metabolic hypothesis is presented for insulin resistance in obesity, in the presence or absence of Type 2 (non-insulin-dependent) diabetes mellitus. It is based on physiological mechanisms including a series of negative feed-back mechanisms, with the inhibition of the function of the glycogen cycle in skeletal muscle as a consequence of decreased glucose utilization resulting from increased lipid oxidation in the obese. It considers the inhibition of glycogen synthase activity together with inhibition of glucose storage and impaired glucose tolerance. The prolonged duration of increased lipid oxidation, considered as the initial cause, may lead to Type 2 diabetes. This hypothesis is compatible with others based on the inhibition of insulin receptor kinase and of glucose transporter activities.

Ultrastructure of the ovary of Dermatobia hominis (Diptera: cuterebridae). II. Origin of the tunica propria in ovarioles

Ovaries up to the 8th day pupae of Dermatobia hominis were studied by transmission electron microscopy. Ovarioles were recognized in ovaries of 4-day old pre-pupae, surrounded by a thin tunica propria of acellular fibrilar material similar in structure to the internal portion of the external tunica of the ovary. There is continuity of the tunica propria and the ovarian tunica, indicating that the former structure originates from the tunica externa. In 5 to 7-day pupae the interstitial somatic cells from the apical region of the ovary, close to the ovarioles, show delicate filamentous material inside of their rough endoplasmic reticulum cisternae; similar material is seem among these cells. Our observations suggest that interstitial somatic cells do not originate the tunica propria but contribute to its final composition.

Genomic determinants of the efficiency of internal ribosomal entry sites of viral and cellular origin

Summary : Internal ribosome entry sites (IRES) are used by viruses as a strategy to bypass inhibition of cap-dependent translation that commonly results from viral infection. IRES are also used in eukaryotic cells to control mRNA translation under conditions of cellular stress (apoptosis, heat shock) or during the G2 phase of the cell cycle when general protein synthesis is inhibited. Variation in cellular expression levels has been shown to be inherited. Expression is controlled, among others, by transcriptional factors and by the efficiency of cap-mediated translation and ribosome activity. We aimed at identifying genomic determinants of variability in IRES-mediated translation of two representative IRES [Encephalomyocarditis virus (EMCV) and X-linked Inhibitor-of-Apoptosis (XIAP) IRES]. We used bicistronic lentiviral constructions expressing two fluorescent reporter transgenes. Lentiviruses were used to transduce seven different laboratory cell lines and B lymphoblastoid cell lines from the Centre d'Etude du Polymorphisme Humain (CEPH; 15 pedigrees; n=209); representing an in vitro approach to family structure allowing genome scan analyses. The relative expression of the two markers was assessed by FACS. IRES efficiency varies according to cellular background, but also varies, for a same cell type, among individuals. The control of IRES activity presents an inherited component (h2) of 0.47 and 0.36 for EMCV and XIAP IRES, respectively. A genome scan identified a suggestive Quantitative Trait Loci (LOD 2.35) involved in the control of XIAP IRES activity. Résumé : Les sites internes d'entrée des ribosomes (IRES = internal ribosome entry sites) sont utilisés par les virus comme une stratégie afin d'outrepasser l'inhibition de traduction qui résulte communément d'une infection virale. Les IRES sont également utilisés par les cellules eucaryotes pour contrôler la traduction de l'ARN messager dans des conditions de stress cellulaire (apoptose, choc thermique) ou durant la phase G2 du cycle cellulaire, situations durant lesquelles la synthèse générale des protéines est inhibée. La variation des niveaux d'expression cellulaire de transcription est un caractère héréditaire. L'expression des gènes est contrôlée entre autre par les facteurs de transcription et par l'efficacité de la traduction initiée par la coiffe ainsi que par l'activité des ribosomes. Durant cette étude nous avons eu pour but d'identifier les déterminants génomiques responsables de la variabilité de la traduction contrôlée par l'IRES. Ceci a été effectué en étudiant deux IRES représentatifs : l'IRES du virus de l'encéphalomyocardite (EMCV) et l'IRES de l'inhibiteur de l'apoptose XIAP (X-linked Inhibitor-of-Apoptosis). Nous avons utilisés des lentivirus délivrant un transgène bicistronique codant pour deux gènes rapporteurs fluorescents. Ces lentivirus ont été utilisés pour transduire sept différentes lignées cellulaires de laboratoire et des lignées cellulaires lymphoblastoïdes B du Centre d'Etude du Polymorphisme Humain (CEPH; 15 pedigrees; n=209) qui représentent une approche in vitro de la structure familiale et qui permettent des analyses par balayage du génome. L'expression relative des deux marqueurs fluorescents a été analysée par FACS. Nos résultats montrent que l'efficacité des IRES varie en fonction du type de cellules. Il varie aussi, pour le même type de cellules, selon les individus. Le contrôle de l'activité de l'IRES est un caractère héritable (héritabilité h2) de 0.47 et 0.36 pour les IRES de EMCV et XIAP respectivement. Le balayage du génome a permis l'identification d'un locus à effets quantitatifs [QTL Quantitative Trait Loci (LOD 2.35)] impliqué dans le contôle de l'activité de l'IRES de XIAP.

Benzodiazepine receptor ligand influences on learning: an endogenous modulatory mechanism mediated by benzodiazepines possibly of alimentary origin

In rats pre-but not post-training ip administration of either flumazenil, a central benzodiazepine (BSD) receptor antagonist, or of n-butyl-B-carboline-carboxylate (BCCB), an inverse agonist, enhanced retention of inhibitory avoidance learning. Flumazenil vlocked the enhancing effect of BCCB, and the inhibitory effect of the BZD agonists clonazepam and diazepam also given pre-training. Post-training administration of these drugs had no effects. The peripheral BZD receptor agonist/chloride channel blocker Ro5-4864 had no effect on the inhibitory avoidance task when given ip prior to training, buth it caused enhancement when given immediately post-training either ip or icv. This effect was blocked by PK11195, a competitive antagonist of Ro5-4864. These results suggest that ther is an endogenous mechanism mediated by BZD agonists, which is sensitive to inverse agonists and that normally down-regulates the formation of memories through a mechanism involving GABA-A receptors and the corresponding chloride channels. The most likely agonists for the endogenous mechanism suggested are the diazepam-like BZDs found in brain whose origin is possibly alimentary. Levels of these BZDs in the cortex were found to sharply decrease after inhibitory acoidance training or mere exposure to the training apparatus.