bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced neuronal cell death after experimental brain injury in mice lacking a functional alternative pathway of complement activation
Authors: Leinhase Iris , Holers V Michael , Thurman Joshua M , Harhausen Denise , Schmidt Oliver I , Pietzcker Malte , Taha Mohy E , Rittirsch Daniel , Huber-Lang Markus , Smith Wade R , Ward Peter A , Stahel Philip F
Published: July 2006

Background

Neuroprotective strategies for prevention of the neuropathological sequelae of traumatic brain injury (TBI) have largely failed in translation to clinical treatment. Thus, there is a substantial need for further understanding the molecular mechanisms and pathways which lead to secondary neuronal cell death in the injured brain. The intracerebral activation of the complement cascade was shown to mediate inflammation and tissue destruction after TBI. However, the exact pathways of complement activation involved in the induction of posttraumatic neurodegeneration have not yet been assessed. In the present study, we investigated the role of the alternative complement activation pathway in contributing to neuronal cell death, based on a standardized TBI model in mice with targeted deletion of the factor B gene (fB-/-), a "key" component required for activation of the alternative complement pathway.

Results

After experimental TBI in wild-type (fB+/+) mice, there was a massive time-dependent systemic complement activation, as determined by enhanced C5a serum levels for up to 7 days. In contrast, the extent of systemic complement activation was significantly attenuated infB-/- mice (P< 0.05,fB-/-vs.fB+/+;t= 4 h, 24 h, and 7 days after TBI). TUNEL histochemistry experiments revealed that posttraumatic neuronal cell death was clearly reduced for up to 7 days in the injured brain hemispheres offB-/- mice, compared tofB+/+ littermates. Furthermore, a strong upregulation of the anti-apoptotic mediator Bcl-2 and downregulation of the pro-apoptotic Fas receptor was detected in brain homogenates of head-injuredfB-/- vs.fB+/+ mice by Western blot analysis.

Conclusion

The alternative pathway of complement activation appears to play a more crucial role in the pathophysiology of TBI than previously appreciated. This notion is based on the findings of (a) the significant attenuation of overall complement activation in head-injuredfB-/- mice, as determined by a reduction of serum C5a concentrations to constitutive levels in normal mice, and (b) by a dramatic reduction of TUNEL-positive neurons in conjunction with an upregulation of Bcl-2 and downregulation of the Fas receptor in head-injuredfB-/- mice, compared tofB+/+ littermates. Pharmacological targeting of the alternative complement pathway during the "time-window of opportunity" after TBI may represent a promising new strategy to be pursued in future studies.
Different profiles of immune reconstitution in children and adults with HIV-infection after highly active antiretroviral therapy
Authors: Resino Salvador , Seoane Elena , Pérez Alicia , Ruiz-Mateos Ezequiel , Leal Manuel , Muñoz-Fernández Maria Á
Published: July 2006

Background

Recent advances in characterizing the immune recovery of HIV-1-infected people have highlighted the importance of the thymus for peripheral T-cell diversity and function. The aim of this study was to investigate differences in immune reconstitution profiles after highly active antiretroviral therapy (HAART) between HIV-children and adults.

Methods

HIV patients were grouped according to their previous clinical and immunological status: 9 HIV-Reconstituting-adults (HIV-Rec-adults) and 10 HIV-Reconstituting-children (HIV-Rec-children) on HAART with viral load (VL) ≤400 copies/ml and CD4+ ≥500 cells/μL at least during 6 months before the study and CD4+ ≤300 cells/μL anytime before. Fifteen healthy-adults and 20 healthy-children (control subjects) were used to calculate Z-score values to unify value scales between children and adults to make them comparable.

Results

HIV-Rec-children had higher T-cell receptor excision circles (TREC) and lower interleukin (IL)-7 levels than HIV-Rec-adults (p < 0.05). When we analyzed Z-score values, HIV-Rec-children had higher TREC Z-score levels (p = 0.03) than HIV-Rec-adults but similar IL-7 Z-score levels. Regarding T-cell subsets, HIV-Rec-children had higher naïve CD4+ (CD4+CD45RA hi+CD27+), naïve CD8+ (CD8+CD45RA hi+CD27+), and memory CD8+ (CD8+CD45RO+) cells/μl than HIV-Rec-adults, but similar memory CD4+ (CD4+CD45RO+) counts. HIV-Rec-children had lower naïve CD8+ Z-score values than HIV-Rec-adults (p = 0.05).

Conclusion

Our data suggest that HIV-Rec-children had better thymic function than HIV-Rec-adults and this fact affects the peripheral T-cell subsets. Thus, T-cell recovery after HAART in HIV-Rec-adults could be the consequence of antigen-independent peripheral T-cell expansion while in HIV-Rec-children thymic output could play a predominant role in immune reconstitution.
Dimensional analysis of MINMOD leads to definition of the disposition index of glucose regulation and improved simulation algorithm
Authors: Nittala Aparna , Ghosh Soumitra , Stefanovski Darko , Bergman Richard , Wang Xujing
Published: July 2006

Background

Frequently Sampled Intravenous Glucose Tolerance Test (FSIVGTT) together with its mathematical model, the minimal model (MINMOD), have become important clinical tools to evaluate the metabolic control of glucose in humans. Dimensional analysis of the model is up to now not available.

Methods

A formal dimensional analysis of MINMOD was carried out and the degree of freedom of MINMOD was examined. Through re-expressing all state variable and parameters in terms of their reference scales, MINMOD was transformed into a dimensionless format. Previously defined physiological indices including insulin sensitivity, glucose effectiveness, and first and second phase insulin responses were re-examined in this new formulation. Further, the parameter estimation from FSIVGTT was implemented using both the dimensional and the dimensionless formulations of MINMOD, and the performances were compared utilizing Monte Carlo simulation as well as real human FSIVGTT data.

Results

The degree of freedom (DOF) of MINMOD was found to be 7. The model was maximally simplified in the dimensionless formulation that normalizes the variation in glucose and insulin during FSIVGTT. In the new formulation, the disposition index (Dl), a composite parameter known to be important in diabetes pathology, was naturally defined as one of the dimensionless parameters in the system. The numerical simulation using the dimensionless formulation led to a 1.5–5 fold gain in speed, and significantly improved accuracy and robustness in parameter estimation compared to the dimensional implementation.

Conclusion

Dimensional analysis of MINMOD led to simplification of the model, direct identification of the important composite factors in the dynamics of glucose metabolic control, and better simulations algorithms.
Six year disease free survival after liver transplantation in a patient with T3 gallbladder carcinoma: case presentation and review of the literature
Authors: Ortiz Jorge , Reich David , Joon Hoon Bae , Martinez Oscar , Manzarbeitia Cosme
Published: July 2006

Background

The incidence of gallbladder carcinoma in cirrhotics is unknown. Known risk factors are primary sclerosing cholangitis and polypoid masses.

Case presentation

A sixty year old with primary sclerosing cholangitis, cirrhosis, and gallbladder polyps underwent liver transplantation. A polypoid lesion measuring 1.5 × 0.5 cm was found on the fundus of the gallbladder. Histological examination revealed moderately differentiated adenocarcinoma with full thickness penetration of the gallbladder encroaching liver parenchyma. Angiolymphatic invasion was noted. The lymph nodes, the cystic duct and the common duct were free of tumor (T3N0M0). Extensive evaluation did not demonstrate metastasis. No chemotherapy was given. He is currently six years post procedure and free of disease.

Conclusion

"Incidentally" discovered stage IIA gallbladder carcinoma may not negatively affect long term survival after liver transplantation.
Climatic reconstructions for the northeast Atlantic region AD 1685-1700: a new source of evidence from naval logbooks
Authors: Wheeler Dennis , Suarez-Dominguez Jose
Published: July 2006

This paper draws on a newly developed source of data in the form of ships' logbooks to cast a detailed light on the weather and climate of a critical period in recent climatic history: the decades of the 1680s and 1690s, possibly the coldest of the last 1000 years. Logbooks of the period provide daily data for wind force, direction, precipitation and general weather conditions. These were abstracted and aggregated into monthly statistics. These data indicate the highly episodic character of air flow patterns at this time, with marked changes of phase between high and low zonality in the westerlies. The data also provide evidence of the stormy character of the period, particularly with respect to summer conditions. Comparisons are made with contemporary and independently derived instrumental and proxy series. The data source is confirmed as providing a valuable addition to climatic sources, and is additionally important because it is based on regular daily observations and made at sea-an area very poorly represented for this time period.
Interpretation of radiocarbon dates from the upper surface of late-Holocene peat layers in coastal lowlands
Authors: Waller M. P. , Long A. J. , Schofield J. E.
Published: July 2006

Marine/brackish clastic sediments replace freshwater peats in the stratigraphic column of many coastal lowland areas bordering the North Sea during the late Holocene. Radiocarbon dates are routinely used to provide a chronology for this shift. We examine the assumptions underpinning this approach. The results of investigations from 13 sites in the Rye area of Romney Marsh, southeast England, are reported. Dates from apparently gradational contacts of a highly humified, laterally persistent, peat layer range from 3170-2840 cal. yr BP to 1290-1050 cal. yr BP. Multiple inundations or prolonged gradual inundation are nevertheless rejected, as discrete post-peat bodies of sediment are absent and because peat growth appears to have slowed-down or ceased at many sites in advance of inundation. Additionally in the Rye area, sharp contacts are widespread and the pollen assemblages rarely indicate the occurrence of transitional plant communities. A review of the dating evidence from other coastal lowland regions reveals that multiple dating of the upper surface of peat beds invariably produces diachronous results. As a consequence time transgressive processes feature prominently as causal mechanisms underlying this shift. However, many of the dating difficulties recognized in the Rye area appear to apply to other regions. We conclude that radiocarbon dates from the upper surface of peat layers should in most instances only be regarded as limiting ages for the deposition of the overlying clastic sediments. New chronologies need to be built without a priori assumptions as to the underlying processes, ideally through the direct dating of the clastic sediments.
Prehistoric maritime migration in the Pacific islands: an hypothesis of ENSO forcing
Authors: Anderson Atholl , Chappell John , Gagan Michael , Grove Richard
Published: July 2006

Long-distance human migration across the Pacific Ocean occurred during the late Holocene and originated almost entirely in the west. As prevailing tradewinds blow from the east, the mechanisms of prehistoric seafaring have been debated since the sixteenth century. Inadequacies in propositions of accidental or opportunistic drifting on occasional westerlies were exposed by early computer simulation. Experimental voyaging in large, fast, weatherly (windward-sailing) double-canoes, together with computer simulation incorporating canoe performance data and modern, averaged, wind conditions, has supported the traditional notion of intentional passage-making in a widely accepted hypothesis of upwind migration by strategic voyaging. The critical assumption that maritime technology and sailing conditions were effectively the same prehistorically as in the historical and modern records is, however, open to question. We propose here that maritime technology during the late-Holocene migrations did not permit windward sailing, and show that the episodic pattern of initial island colonization, which is disclosed in recent archaeological data, matches periods of reversal in wind direction toward westerlies, as inferred from the millennial-scale history of ENSO (El Niño-Southern Oscillation).
Environmental history of the dry forest biome of Guerrero, Mexico, and human impact during the last c. 2700 years
Authors: Berrío Juan Carlos , Hooghiemstra Henry , van Geel Bas , Ludlow-Wiechers Beatriz
Published: July 2006

Two lake sediment cores from Madre del Sur mountain range,Guerrero State, west-central Mexico were studied to examine the pastdynamics of the dry forest biome. Pollen, spores of coprophilousfungi, cyanobacteria and lithological changes are presented. The390-cm Tixtla core (1730'N, 99°24W, 1400 maltitude) represents the last 2700 cal. yr; the 340-cm Huitziltepeccore (17°45N, 99°28W, 1430 m altitude) representsthe last 2050 cal. yr. Pollen shows climate-dependent competitionbetween dry deciduous forest (with Asteraceae, Chamaesyce-type,Bursera, Euphorbia, Myrica and Lysiloma-Pithecellobium-type as main components) and moister(mesophyllous) forest (with Pinus, Quercus, Alnus and Juglans). Human impact on the environment is apparent duringthe entire record, as evidenced by crop cultivation (Zea mays,Amaranthus, Capsicum, Chenopodium), coprophilous fungi (Podospora-type and Sporormiella-type), deforestation (at Tixtla in particular) and lake eutrophication, ie, cyanobacteria blooms. Environmental change at both sites is summarized as follows. Period 1 (2700-2450 cal. yr BP): abundant dry deciduous forest and climate conditions drier than today. Period 2 (2450-1950 cal. yr BP): little change in proportions of dry deciduous and mesophyllous forest but floral composition of the forests differed between sites. Human occupation was low. Period 3 (1950-1550 cal. yr BP): dry deciduous forest decreased while mesophyllous forest increased, indicating more humid climatic conditions. Populations expanded significantly around 1950 cal. yr BP. Period 4 (1550-1070 cal. yr BP): maximum expansion of mesophyllous forest. Climate was more humid than today. Pre-Hispanic populations at Tixtla reached high numbers leading to deforestation and eutrophication. Period 5 (1070-c. 750 cal. yr BP): shows abundant mesophyllous forest and lowest proportions of dry deciduous forest. Climate continued to be humid. There is evidence of forest harvesting, crop cultivation and dense human population. Period 6 (c. 750-225 cal. yr BP): dry deciduous forest expanded and mesophyllous forest decreased. There was significant deforestation by pre-Hispanic people around Lake Tixtla. High population densities and frequent fires at both sites caused eutrophication of the lakes. Domesticated herbivores were introduced ∼ad 1500 and the presence of dung is reflected in the record of coprophilous fungi. Period 7 (the last 225 calendar years): the basins were used intensively by local people and their cattle. Dry deciduous forest continued to increase while mesophyllous forest decreased.
Forest dynamics in the Pfyn forest in recent centuries (Valais, Switzerland, Central Alps): interaction of pine (Pinus sylvestris) and oak (Quercus sp.) under changing land use and fire frequency
Authors: Bendel Muriel , Tinner Willy , Ammann Brigitta
Published: July 2006

Pinus sylvestris is co-dominant in many areas of eastern and northern Europe. In Switzerland, the Pfyn forest is considered to be the largest natural forest of Pinus sylvestris. Its development under changing land use during recent centuries is largely unknown. Of particular interest is the interaction between pine and oak, for it has been suggested that oak has benefited from the strong decline in economic uses of the forest such as pasturing, litter removal and logging. In order to improve understanding of the dynamics in this particular forest type over time, the vegetation and fire history of the Pfyn forest were reconstructed by pollen and charcoal analyses of the sediments of Pfafforetsee. Four phases of decline in Pinus pollen percentages are explained by logging events and other anthropogenic activities during recent centuries. During the twentieth century human impact on Pinus was probably exacerbated by forest fires. When human influence ceased or declined, Pinus was able to regain its former importance within a few decades. Whereas Pinus experienced considerable change, Quercus species (Q. pubescens, Q. petraea and Q. robur) exhibit constant and low pollen values throughout the record. Under constant climatic conditions, pine should therefore not suffer late-successional replacements by oak in the Pfyn forest. This finding is especially important for nature conservation and forest management, since strong decline in Pinus sylvestris in the canton of Valais has also been interpreted as a consequence of successional dynamics towards a more natural vegetation.
Modern pollen assemblages from grazedvegetation in the western Pyrenees, France: a numerical tool for more precise reconstruction of past cultural landscapes
Authors: Mazier Florence , Galop Didier , Brun Cecile , Buttler Alexandre
Published: July 2006

Modern pollen assemblages from grazed vegetation in the Pyrenees Mountains (France) were studied with the aim of providing a calibrated model for reconstructing past pastoral activities. The modem analogues were selected to cover the major gradients of grazing pressure and degree of openness. The vegetation was surveyed by means of the synusial integrated method, assessing the structure and the patchiness of the pastoral phytoceonoses. A correlative model (Redundancy analysis) was devised relating 61 modern pollen spectra with 37 explanatory vegetation and land-use variables. It was shown that wooded, open grazed and nitrophilous sites are clearly separated from one another and that the model can be simplified using three relevant vegetation types as explanatory variables: dry heathland, semi-open oak forest and overgrazed community, respectively related to gradients of openness, soil richness and grazing pressure. When reconstructing past pastoral activities with fossil pollen spectra, it is important to consider scale-dependent influences of plant species. Low frequencies of well-dispersed taxa such as Artemisia, Chenopodiaceae, Plantago lanceolata and Plantago majorlmedia must be interpreted with care since they reflect more regional, rather than local, input into the pastoral landscape. In contrast, the simultaneous occurrence of Asteroideae, Cichorioideae, Cirsium-type, Galium-type, Ranunculaceae, Stellaria-type and Potentilla-type pollen is clearly related to grazing on a local scale. Calculation of Davis indices also shows that Cichorioideae, Galium-type and Potentilla-type indicate the very local presence of the corresponding plants. These pastoral plant indicators may have a limited geographical validity, ie, mountainous regions with crystalline bedrock, which may indeed also provide the framework for the application to fossil spectra of the modem pollen/vegetationAand-use models presented here.
A high mountain pollen-altitude calibration set for palaeoclimatic use in the tropical Andes
Authors: Rull Valenti
Published: July 2006

The numerical relationship between modem pollen assemblages and altitude in high mountain environments from the northern Andes is analysed, in order to found inference models that allow estimating palaeoaltitudes and palaeotemperatures from past pollen records. The calibration set (DM) consists of a 50-sample altitudinal transect between-2300 and-4600 m altitude. The overall and individual pollen responses to altitude were tested by correspondence analysis (CA), generalized linear regression (HOF) and weighted averaging (WA). Transfer functions were derived by weighted averaging partial least squares (WA-PLS) regression. Overall, altitude is the main controlling factor for the composition of pollen assemblages, as shown by the high correlation between altitude and the first CA component (r =-0.88). Individually, around 35% of the 82 pollen taxa show a significant response to altitude through monotonic or unimodal functions. The best transfer function obtained has a good statistical performance, as shown by the determination coefficient (r2tck =0.78). The prediction power, as measured by the root mean square error of prediction (RMSEP), is of 256 m (12% of the total altitudinal gradient), which is equivalent to-1.5C. These parameters fall within the performance range of the inference models developed elsewhere using pollen and other biological proxies. It is concluded that the DM training set is useful to reconstruct Pleistocene and major Holocene palaeoclimatic trends. This study demonstrates the suitability of establishing reliable transfer functions for palaeoclimatic estimation in the highest altitudes of the tropical Andes, and encourages their continued improvement.
Holocene climatic and environmental changes in the arid and semi-arid areas of China: a review
Authors: Feng Z.-D. , An C. B. , Wang H. B.
Published: July 2006

This paper reviews recently published literature, most of which was published in Chinese, and searches for regional patterns of Holocene changes useful in depicting global patterns. The Holocene in the Xinjiang region can be divided into three stages: a warming and dry early stage (from 11 10 to 8-7 ka BP), a warm and wet middle stage (from 8-7 to 4.5-3 ka BP) and a fluctuating cool and dry late stage (since 4.5-3 ka BP). The Holocene in the northern Tibetan Plateau can also be divided into three stages: a warming and wet stage (from 10.5-10 to 5-4 ka BP), followed by a variable drying and probably warm stage (5-4 to 3 ka BP) and ending with a cool and dry stage (since 3 ka BP). In the Inner Mongolian Plateau, the early Holocene (from 10.5-9.5 to 8-7.5 ka BP) was warming and dry, and a warm and wet climate occurred from 7.5 to 3.5, during which the best time was 6.3-3.8 ka BP; the climate has been variably drying and probably cooling since 3.5 ka BP. In the northwestern part of the Loess Plateau, several Holocene palaeosols have been identified (10-9, 7.5-5, 4-3 and 2.7-2 ka BP) with the 7.5-5 ka BP palaeosol being most strongly expressed. The best-developed palaeosol-equivalent in major valleys is a swamp-wetland facies deposited between 8885 and 3805 14C yr BP under an extremely wet regime. The climate has fluctuated significantly at least three times around a dry and probably cool regime after the swamp-wetland facies-depositional period. Our summary shows that the Holocene Climatic Optimum occurred nearly contemporaneously (8-5 ka BP) at all sites in the Xinjiang region, in the Inner Mongolian Plateau and in the northwestern part of the Loess Plateau. A warming and wet early Holocene (10-8 ka BP) in the northern Tibetan Plateau is most likely related to high effective soil moisture resulting from snow and ice melting. We propose here that the middle Holocene Climatic Optimum (8-5 ka BP) in arid to semi-arid China was primarily a delayed response of the low latitude oceans to high latitude peak insolation (9-8 ka BP).
Variability in North Atlantic marine radiocarbon reservoir effects at c. AD 1000
Authors: Ascough P. L. , Cook G. T. , Church M. J. , Dugmore A. J. , Arge S. V. , McGovern T. H.
Published: July 2006

14C age measurements made on samples from three archaeological sites located on North Atlantic coasts were used to investigate the marine reservoir effect (MRE) at c.AD 1000. This is an important period within human cultural and palaeoenvironmental research as it is a time when Norse expansion to the North Atlantic islands occurred, during what appears to be a period of ameliorating climatic conditions. This makes improved chronological precision and accuracy at this time highly desirable. The data indicate a potential latitudinal variation in MRE at c. AD 1000 from a ΔR of-142±16 14C yr at Omey Island (53° 32' N) to 64±13 14C yr at Undir Junkarinsfløtti (61° 51' N). The results are compared with modern assessments of MRE values within the context of oceanographic and climatic regimes that provide a possible driving mechanism for spatial and temporal variation in MRE.
Terrestrial mollusc succession and stratigraphy of a Holocene calcareous tufa deposit from the Fyledalen valley, southern Sweden
Authors: Gedda B.
Published: July 2006

A Holocene calcareous tufa deposit in the Fyledalen Valley in southern Sweden was investigated with respect to molluscs, pollen, plant macrofossils and Coleoptera remains. The investigation recovered four mollusc species that today are severely threatened and included in the Swedish Red List of Endangered Species and/or the European Community's Natura 2000 programme. These include Vertigo genesii (Gredler), Vertigo geyeri Lindholm, Cochlicopa nitens (Gallenstein) and Vertigo moulinsiana (Dupuy). Tufa formation was initiated in the early Preboreal (after 11 500 cal. BP), when an open birch-pine forest dominated the area and stopped in the late Boreal (after 8800 cal. BP) when deciduous trees had become established. The presence of the molluscan species Vallonia pulchella (Müller), Columella columella (Martens), Vertigo genesii, Pupilla muscorum (L.) and Euconulus alderi (Gray), coupled with an almost complete lack of shade-demanding taxa, suggests an open marsh environment throughout the time of tufa deposition. The mollusc succession shows evidence of increasing temperature. Columella columella, commonly associated with open arctic-alpine habitats is present at the base of the profile in the early Preboreal, whilst Vertigo genesii, which commonly is associated with open arctic-alpine habitats or calcareous springs, persists until the mid-Boreal (∼ 8800 cal. BP). The tufa deposition ends when the regional groundwater levels rise, approximately 8800 cal. BP, more thermophilous molluscs, such as Vertigo moulinsiana and V angustior Jeffreys and the aquatic Bithynia tentaculata (L.), Radix peregra (Müller) and Planorbis planorbis (L.) colonize the site. Stratigraphic correlations, as well as faunal and floral comparisons, are made with nearby sites.
Attention to Maternal Multimodal Naming by 6‐ to 8‐Month‐Old Infants and Learning of Word–Object Relations
Authors: Gogate Lakshmi J. , Bolzani Laura H. , Betancourt Eugene A.
Published: July 2006

We examined whether mothers' use of temporal synchrony between spoken words and moving objects, and infants' attention to object naming, predict infants' learning of word–object relations. Following 5 min of free play, 24 mothers taught their 6‐ to 8‐month‐olds the names of 2 toy objects,GowandChi, during a 3‐min play episode. Infants were then tested for their word mapping. The videotaped episodes were coded for mothers' object naming and infants' attention to different naming types. Results indicated that mothers' use of temporal synchrony and infants' attention during play covaried with infants' word‐mapping ability. Specifically, infants who switched eye gaze from mother to object most frequently during naming learned the word–object relations. The findings suggest that maternal naming and infants' word‐mapping abilities are bidirectionally related. Variability in infants' attention to maternal multimodal naming explains the variability in early lexical‐mapping development.
Encoding Action Roles in Meaningful Social Interaction in the First Year of Life
Authors: Schöppner Barbara , Sodian Beate , Pauen Sabina
Published: July 2006

Previous research has shown that 6‐ to 9‐month‐old infants detect role reversals in dyadic interaction involving 2‐argument relations. These studies extend this line of research to a 3‐argument structure: An agent gives an object to a recipient. We conducted 4 experiments in a novelty‐preference paradigm. Infants were habituated to videotaped sequences of a puppet giving a flower to another puppet. In the test phase, the puppets' spatial positions were switched, and infants alternately saw role‐reversal and direction‐reversal trials. Results indicate that 10.5‐ and 12‐month‐olds but not 9‐month‐olds selectively encoded the change of action role (agent‐recipient) over a change in the spatiotemporal properties of the interaction and that action role encoding was specific to intentional relations in a 3‐argument structure. Thus, infants at the end of their 1st year seem to be sensitive to movement cues that specify intentional relations between an agent and a recipient.
Two‐Month‐Old Infants' Sensitivity to Social Contingency in Mother–Infant and Stranger–Infant Interaction
Authors: Bigelow Ann E. , Rochat Philippe
Published: July 2006

Two‐month‐old infants (N = 29) participated in face‐to‐face interactions with their mothers and with strangers. The contingent responsiveness for smiles and vocalizations, while attending to the partner, was assessed for each partner in both interactions. For smiles and for vocalizations, infants were less responsive to the stranger relative to the mother when the stranger's contingent responsiveness was either more contingent or less contingent than that of the mother. Results are supportive of the hypothesis that young infants develop sensitivities to levels of social contingency present in their maternal interactions, which influence their responsiveness to others.
Can 18‐Month‐Old Infants Learn Words by Listening In on Conversations?
Authors: Floor Penelope , Akhtar Nameera
Published: July 2006

Previous research has shown that children as young as 2 can learn words from 3rd‐party conversations (Akhtar, Jipson, & Callanan, 2001). The focus of this study was to determine whether younger infants could learn a new word through overhearing. Novel object labels were introduced to 18‐month‐old infants in 1 of 2 conditions: directly by an experimenter or in the context of overhearing the experimenter use the word while interacting with another adult. The findings suggest that, when memory demands are not too high, 18‐month‐old infants can learn words through overhearing.
Ca2+-Dependent Regulation of Calcitonin Gene Expression by the Transcriptional Repressor DREAM
Authors: Matsuda Miho , Yamamoto Tada-aki , Hirata Masato
Published: July 2006

Calcitonin (CT), whose secretion from thyroid glands is regulated by increases in the concentration of extracellular Ca2+, is a well-known hormone that regulates calcium homeostasis. However, the molecular mechanisms underlying the gene expression dependent on Ca2+ have not been clarified. The downstream regulatory element (DRE) antagonist modulator (DREAM) was recently identified as a Ca2+-dependent transcriptional repressor. In the present study, we investigated the possible involvement of DREAM in the regulation of CT gene expression and secretion. A luciferase assay using TT cells, a thyroid carcinoma cell line, showed that a particular region in the CT gene promoter repressed the promoter activity under basal conditions but induced the activity when the Ca2+ concentration was increased. We found two DRE sequences in a region located upstream from the transcription start site. Gel retardation assay confirmed that DREAM bound to the CT-DRE and also indicated that DREAM bound to the DRE in a Ca2+-dependent manner. We generated stable transfectants of TT cells with wild-type or mutant DREAM, which lacked the responsiveness to Ca2+ changes. In contrast to the wild type, overexpression of the mutant DREAM inhibited the increase in CT secretion induced by a calcium ionophore. The addition of forskolin to increase cAMP activated the CT promoter, probably by the interaction of DREAM with cAMP-responsive element binding proteins, independent on the activation by Ca2+. Together, these results suggest that DREAM plays an important role in human CT gene expression in a Ca2+- and cAMP-dependent manner.
Remodeling of White Adipose Tissue after Retinoic Acid Administration in Mice
Authors: Mercader Josep , Ribot Joan , Murano Incoronata , Felipe Francisco , Cinti Saverio , Bonet M. Luisa , Palou Andreu
Published: July 2006

A reduced brown adipose phenotype in white adipose tissue (WAT) may contribute to obesity and type 2 diabetes in humans. Retinoic acid, the carboxylic form of vitamin A, triggers in rodents a reduction of body weight and adiposity and an increased expression of uncoupling proteins in brown adipose tissue and skeletal muscle. In this study, we investigated possible remodeling effects of all-trans retinoic acid (ATRA) in WAT depots. Changes in the expression of genes related to thermogenesis and fatty acid oxidation and levels of phosphorylated retinoblastoma protein were analyzed in WAT depots of adult NMRI male mice acutely injected with ATRA or vehicle, together with biometric and blood parameters. Body fat loss after ATRA treatment was unaccompanied by any increase in circulating nonesterified fatty acids or ketone bodies and accompanied by increased rectal temperature. The treatment triggered an up-regulation of the mRNA levels of uncoupling proteins 1 and 2, peroxisome proliferator-activated receptor γ coactivator-1α, peroxisome proliferator-activated receptor α, muscle- and liver-type carnitine palmitoyltransferase 1, and subunit II of cytochrome oxidase in different WAT depots. Levels of phosphorylated retinoblastoma protein in WAT depots were increased after ATRA treatment. Adipocyte size was reduced, and the number of multilocular adipocytes was increased in inguinal WAT of ATRA-treated mice. The results indicate that ATRA favors the acquisition of brown adipose tissue-like properties in WAT. Understanding the mechanisms and effectors involved in the remodeling of WAT can contribute to new avenues of prevention and treatment of obesity and type 2 diabetes.
Persistent Expression of Notch2 Delays Gonadotrope Differentiation
Authors: Raetzman Lori T. , Wheeler Bayly S. , Ross Shelley A. , Thomas Paul Q. , Camper Sally A.
Published: July 2006

Normal pituitary gland development requires coordination between maintenance of progenitor cell pools and selection of progenitors for differentiation. The spatial and temporal expression of Notch2 during pituitary development suggested that it could control progenitor cell differentiation in the pituitary. Consistent with this idea, Notch2 is not expressed in Prop1 mutants, and anterior pituitary progenitors in Prop1 mutants appear to be unable to transition from proliferation to differentiation properly, resulting in anterior lobe failed cell specification and evolving hypoplasia. To test the function of Notch2 directly, we used the αGSU subunit promoter to express activated NOTCH2 persistently in pre-gonadotropes and pre-thyrotropes of transgenic mice. At birth, there is a small reduction in the population of fully differentiated thyrotropes and almost no fully differentiated gonadotropes. The temporal and spatial expression of Hey1 suggests that it could be a mediator of this effect. Gonadotropes complete their differentiation program eventually, although expression of LH and FSH is mutually exclusive with NOTCH2 transgene expression. This demonstrates that activated Notch2 is sufficient to delay gonadotrope differentiation, and it supports the hypothesis that Notch2 regulates progenitor cell differentiation in the pituitary gland.
Molecular Orbital Considerations on Interaction of 2-Aminopyridine with Formic Acid in the Ground State
Authors: Inuzuka Kozo , Fujimoto Akira
Published: July 2006

In order to ascertain the formation processes of the tautomer and proton-transferred complexes in the 2-aminopyridine–acetic acid system in the ground state, a molecular orbital calculation was carried out for the 2-aminopyridine–formic acid system by the ab initio STO-3G method with full-geometry optimization of the complex. The following conclusions were drawn from the present calculation: (1) The amino–imino tautomerization in the 2-aminopyridine–formic acid system proceeds through a double proton transfer process between 2-aminopyridine and formic acid. (2) The formation of a proton-transferred complex in the 2-aminopyridine–formic acid system is difficult in the ground state. This conclusion may be applicable to the 2-aminopyridine–acetic acid system. (3) In the case of the ab initio STO-3G calculation a full-geometry optimization of the complex plays an important role in elucidating the stabilization energies and geometries of the tautomer and proton-transferred complexes. (4) A full-geometry optimization of the complex model is not so important for evaluating the hydrogen bond energy of the stable hydrogen-bonded complex, but is necessary for elucidating the effect of hydrogen bond formation on the molecular geometry of the complex. (5) The bisectal angle of the NH2 group, calculated by the ab initio STO-3G method, becomes much larger than the experimental value. Further, the energy difference between the planar and pyramidal 2-aminopyridine with respect to the NH2 group is much larger than the experimental value.
Synthesis and Properties of Diamino-Substituted Dipyrido [3,2-a: 2′,3′-c]phenazine
Authors: Yamada Masaki , Tanaka Yoshihito , Yoshimoto Yasuyuki , Kuroda Shigeyasu , Shimao Ichiro
Published: July 2006

A heteroaromatic compound 3,6-diaminodipyrido[3,2-a: 2′,3′-c]phenazine was synthesized with an improved method to convert 1,10-phenanthroline derivatives to the corresponding 5,6-diones. It was shown that the electron-donating effects of amino substituents were extended not only to pyridine rings but also to the phenazine ring.
Re-evaluation of the Acid Dissociation Constants of the Hydroxyl Groups in Tetrasodium 25,26,27,28-Tetrahydroxycalix[4]arene-5,11,17,23-tetrasulfonate
Authors: Yoshida Isao , Yamamoto Nobuhiro , Sagara Fumio , Ishii Daido , Ueno Keihei , Shinkai Seiji
Published: July 2006

The acid dissociation constants of the hydroxyl groups in tetrasodium 25,26,27,28-tetrahydroxycalix[4]arene-5,11,17,23-tetrasulfonate (CALX-S4) were determined at 25 °C by potentiometric and spectrophotometric titration methods. The first acid dissociation constant(pKa1) was found to be 3.26 ± 0.02 (μ = 0.1 with KNO3), which demonstrated a remarkable pKa shift due to intramolecular hydrogen-bonding interactions among the hydroxyl groups in CALX-S4. On the other hand, considerably weak acidities were observed on the residual three hydroxyl groups of CALX-S4 (pKa2 = 11.8 ± 0.3 (μ = 0.1 with KNO3), 11.3 ± 0.3 (μ = 2.0 with KCl), pKa3 = 12.8 ± 0.3 (μ = 2.0 with KCl), and pKa4= ca. 14 (μ = 2.0 with KCl)).
Preparation and Characterization of Palladium(I) and Platinum(I) Dinuclear Complexes Bridged by 2-(Dimethylphosphino)pyridine
Authors: Suzuki Takayoshi , Fujita Junnosuke
Published: July 2006

A series of dinuclear complexes containing Me2Ppy ( = 2-(dimethylphosphino)pyridine) as a bridging ligand, [MM′X2(μ-Me2Ppy)2] (M, M′ = Pd(I), Pt(I); X = Cl, Br, and I), have been prepared by reactions between [MX2(Me2Ppy-P)2] and [M′2(dba)3] (dba = 1,5-diphenyl-1,4-pentadien-3-one). In these reactions it has been found by 31P{1H} NMR studies that a dimeric head-to-head isomer was formed in the first place and then isomerized to a head-to-tail isomer. The reactions for analogous Ph2Ppy ( = 2-(diphenylphosphino)pyridine) complexes have been also examined in the same manner. The monomeric Pd(II) complexes reacted more rapidly than did the corresponding Pt(II) complexes in these dimerization and isomerization reactions. For each halogeno series of the Me2Ppy and Ph2Ppy complexes, it seems that the dimerization occurs faster in the order of Cl < Br < I, while the order is reversed in the isomerization, Cl > Br > I. The Me2Ppy complexes isomerized to a head-to-tail isomer more rapidly than did the Ph2Ppy complexes, indicating a larger trans effect of Me2Ppy than Ph2Ppy.
Solid State Oscillatory Reaction. I. Thermal Decomposition Studies of [Co(NH3)6]Br3 and CoBr2·2H2O
Authors: Patil Murlidhar D , Natu Gopal N , Kulkarni Shantaram B
Published: July 2006

Thermogravimetric analysis, TGA, of cobalt(II)bromide, [Co(NH3)6]Br3 –henceforth referred to by the shortname HCBR– was carried out using a wide diameter short one and a narrow diameter long sample cups. In the former type of cup the TGA trace was similar to that reported one. However, when the latter cup was used, the TGA showed oscillations in the % weight-loss. Cobalt(II)bromide, CoBr2, is formed as an intermediate product in the thermal decomposition of HCBR. The oscillatory nature of weight-loss curve was studied for both HCBR and CoBr2.

The oscillatory behavior in the present system has been confirmed on the basis of the following experiments:

(a) Dynamic TGA and differential thermal analysis, DTA, of HCBR and CoBr2·2H2O.

(b) Isothermal TGA by weight-loss method for HCBR and CoBr2.

(c) Thermal decomposition studies, in closed system, of (i) CoBr2 and of (ii) CoO in a mixture of O2 and Br2 gases, and of a mixture of (iii) Co3O4 and CoBr2 in dry nitrogen.

The oscillations in the composition of the solid residue were attributed to the formation of CoOBr as an intermediate. Final product of thermal decomposition of CoBr2 in air is Co3O4. Hence it is possible to imagine that the point of CoOBr formation makes branching off point. This sets the reaction to oscillate in the composition domain. Therefore, it was thought that Edelstein mechanism would be operative in this reaction. Alternately, the population growth model may also be used to explain this observation. Formation of CoOBr was thought to be the weight-loss step, i.e. decrease in the ‘population’ of CoBr2, while the formation of CoBr2 was the weight-gain step, i.e. increase in the ‘population’ of CoBr2 under the proposed reaction, CoBr2 + 1/2O2   CoOBr. The purpose of this article is, therefore, to present the interesting facts of this reaction before the readers, and not to ascribe any particular model for its explanation.
Reactivity of the Transient UV-Band Produced in Irradiated Liquid Carbon Tetrachloride with Various Alcohols
Authors: Sumiyoshi Takashi , Katayama Meiseki
Published: July 2006

The reactivities of the transient UV-band with a peak at 330 nm produced in irradiated liquid carbon tetrachloride with various alcohols have been measured using the absolute technique of pulse radiolysis. The obtained bimolecular rate constants have been compared with those previously determined for the reaction of chlorine atoms with various alcohols using the competitive scavenging method. The values of reaction rate constants of the UV-band are nearly twice those of chlorine atoms. Similar kinetic isotope effects were observed for deuterated methanol and 2-methyl-2-propanol. However, the dependence on the structure of the alcohols, which is characteristic for hydrogen abstraction from alcohols by chlorine atoms, has not been established by the reaction of the UV-band. These results strongly suggest that the assignment of the UV-band to chlorine atoms is not plausible, and instead, support the assignment to parent cations.
A Water-Soluble Spin Probe Newly Developed for Liposomal Studies
Authors: Sunamoto Junzo , Akiyoshi Kazunari , Kihara Tetsuji , Endo Masayuki
Published: July 2006

A water-soluble spin probe, disodium 4-[(4,8-sulfonatooxy-2-naphthyl)thioureylene]-2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO-T) was newly synthesized and characterized comparing with several different TEMPO derivatives from the view point of a possibility of utilization in the liposomal studies. Of TEMPO derivatives studied, TEMPO-T was the best probe because of the high water solubility, the less lipophilicity, the less leakiness from liposome, and the reliable stability to both temperature and pH changes.
Photochemical Reduction of (η5-Cyclopentadienyl)(1,2-disubstituted 1,2-ethylenedichalcogenolato)cobalt(III) and (η5-Cyclopentadienyl)(1,2-benzenedithiolato)cobalt(III) Complexes in the Presence of Triethanolamine
Authors: Akiyama Takeo , Watanabe Yoshihiro , Miyasaka Akiko , Komai Toru , Ushijima Hirobumi , Kajitani Masatsugu , Shimizu Kunio , Sugimori Akira
Published: July 2006

The title complexes, [Co(cp)(S2C2Y2)](cp = η5-C5H5) (1) (a: Y = Ph, b: Y = 2-pyridyl, c: Y = 4-pyridyl, d: Y = −CO2Me, e: Y = −CN), [Co(cp)(S2C6H4)] (2), [Co(cp)(Se2C2Ph2)] (3), and [Co(cp)(SeSC2Ph2)] (4), are photochemically reduced to give one-electron reduced species, Co(II) complexes, under UV-irradiation in the presence of an electron donor, triethanolamine (TEOA), in acetonitrile solutions. The photoreduction is wavelength dependent. The 313 nm light is the most effective (Φ = 0.002–0.018) for all the complexes used, and the light of wavelength longer than 365 nm is ineffective for the photoreduction of 1–4. The irradiation with 254 nm light brings about decomposition of the complexes.
Receptor Interactions of Synthetic Morphiceptin Analogs Containing Phenylalanine Homologs in Position 4
Authors: Sakaguchi Kazuyasu , Costa Tommaso , Sakamoto Hiroshi , Shimohigashi Yasuyuki
Published: July 2006

A series of phenylalanine homologs with elongated phenylalkyl side chains (R = –(CH2)n-C6H5, n = 1–4) have been incorporated into opioid peptide morphiceptin at position 4 in order to elucidate a role of the amino acid residue in the molecular mechanism of receptor activation. The receptor specificity and selectivity of peptides synthesized were examined in the radio-ligand receptor binding assays using tritiated DAGO- and DADLE-enkephalins. [Phe4]Morphiceptin was most potent for the μ receptors and showed the most pronounced μ/δ-receptor selectivity with a specific ratio of 410. Its μ-affinity was about three times stronger than morphiceptin. All analogs showed very similar CD spectra, suggesting that these peptides have a similar backbone conformation. The results strongly suggest that, besides the backbone conformation, the side-chain aromatic rings at positions 1 (Tyr), 3 (Phe), and 4 (Phe) array in a specific stereoorientation and this array is important to activate μ-receptors. Analogs with longer phenylalkyl side chains appeared not to retain such an arrangement due to the steric hindrance caused by the presence of more than two methylene groups.
A Computational Approach to the Structure and Motion of Hexakis(pentyloxy)triphenylene(THE5) in Discotic Mesophase
Authors: Ono Isamu , Kondo Shoichi
Published: July 2006

A molecular dynamics simulation using the atom–atom potential was applied to THE5 of a disk-like mesogenic molecule. The calculations were carried out in a canonical (NVT) ensemble. The results show that the time-averaged molecular properties and molecular ordering are in agreement with experiment. The effects of molecular flexibility in side chains are clearly demonstrated in the profile of the order parameters of each C–H bond.
A Rechargeable Battery Using Electrochemically-Doped Poly(3-vinylperylene) as an Electrode Material
Authors: Jeon Il-Ryon , Noma Naoki , Shirota Yasuhiko
Published: July 2006

A rechargeable battery using electrochemically-doped poly(3-vinylperylene) as a cathode and lithium as an anode was fabricated, and its performance characteristics were examined. The battery exhibits a flat discharge cell voltage at current densities up to 0.8 mA cm−2 with high coulombic efficiency and good cyclability.