The monofunctional platinum(II) compounds, phenanthriplatin and pyriplatin, modulate apoptosis signaling pathways in HEI-OC1 auditory hybridoma cells

Cisplatin is a platinum(II) chemotherapy drug that can cause the side-effect of ototoxicity and hearing loss. The monofunctional platinum(II) complexes, phenanthriplatin and pyriplatin, have recently been investigated as anti-cancer agents but their side-effects are largely unknown. Here, we used the auditory hybridoma cell line, HEI-OC1, to investigate the ototoxicity of cisplatin, phenanthriplatin and pyriplatin. The effect of these compounds against cellular viability, on reactive oxygen species (ROS) production, mitochondrial membrane polarization, caspase-3/7 activity, DNA integrity and caspase-12 expression were measured using spectrophotometric, flow cytometric and blot analyses. We found that the monofunctional complexes and cisplatin decreased cellular viability. All three compounds increased ROS yield at 24 h, but at 48 h, ROS levels returned to normal. Also, the compounds did not depolarize the mitochondrial membrane. All three compounds reduced caspase-3/7 activity at 24 h; cisplatin increased caspase-3/7 activity and caused apoptosis at 48 h. Caspase-12 expression was associated with all three compounds. In summary, the monofunctional complexes may cause ototoxicity like cisplatin. Phenanthriplatin and pyriplatin may cause ototoxicity initially by inducing ROS production, but they may also signal through distinct apoptotic pathways that do not integrate caspases-3/7, or may act at different time-points in the same pathways.

Fungal Planet description sheets: 951-1041

Novel species of fungi described in this study include those from various countries as follows: Antarctica, Apenidiella antarctica from permafrost, Cladosporium fildesense from an unidentified marine sponge. Argentina, Geastrum wrightii on humus in mixed forest. Australia, Golovinomyces glandulariae on Glandularia aristigera, Neoanungitea eucalyptorum on leaves of Eucalyptus grandis, Teratosphaeria corymbiicola on leaves of Corymbia ficifolia, Xylaria eucalypti on leaves of Eucalyptus radiata. Brazil, Bovista psammophila on soil, Fusarium awaxy on rotten stalks of Zea mays, Geastrum lanuginosum on leaf litter covered soil, Hermetothecium mikaniae-micranthae (incl. Hermetothecium gen. nov.) on Mikania micrantha, Penicillium reconvexovelosoi in soil, Stagonosporopsis vannaccii from pod of Glycine max. British Virgin Isles, Lactifluus guanensis on soil. Canada, Sorocybe oblongispora on resin of Picea rubens. Chile, Colletotrichum roseum on leaves of Lapageria rosea. China, Setophoma caverna from carbonatite in Karst cave. Colombia, Lareunionomyces eucalypticola on leaves of Eucalyptus grandis. Costa Rica, Psathyrella pivae on wood. Cyprus, Clavulina iris on calcareous substrate. France, Chromosera ambigua and Clavulina iris var. occidentalis on soil. French West Indies, Helminthosphaeria hispidissima on dead wood. Guatemala, Talaromyces guatemalensis in soil. Malaysia, Neotracylla pini (incl. Tracyllales ord. nov. and Neotracylla gen. nov.) and Vermiculariopsiella pini on needles of Pinus tecunumanii. New Zealand, Neoconiothyrium viticola on stems of Vitis vinifera, Parafenestella pittospori on Pittosporum tenuifolium, Pilidium novae-zelandiae on Phoenix sp. Pakistan, Russula quercus-floribundae on forest floor. Portugal, Trichoderma aestuarinum from saline water. Russia, Pluteus liliputianus on fallen branch of deciduous tree, Pluteus spurius on decaying deciduous wood or soil. South Africa, Alloconiothyrium encephalarti, Phyllosticta encephalarticola and Neothyrostroma encephalarti (incl. Neothyrostroma gen. nov.) on leaves of Encephalartos sp., Chalara eucalypticola on leaf spots of Eucalyptus grandis × urophylla, Clypeosphaeria oleae on leaves of Olea capensis, Cylindrocladiella postalofficium on leaf litter of Sideroxylon inerme, Cylindromonium eugeniicola (incl. Cylindromonium gen. nov.) on leaf litter of Eugenia capensis, Cyphellophora goniomatis on leaves of Gonioma kamassi, Nothodactylaria nephrolepidis (incl. Nothodactylaria gen. nov. and Nothodactylariaceae fam. nov.) on leaves of Nephrolepis exaltata, Falcocladium eucalypti and Gyrothrix eucalypti on leaves of Eucalyptus sp., Gyrothrix oleae on leaves of Olea capensis subsp. macrocarpa, Harzia metrosideri on leaf litter of Metrosideros sp., Hippopotamyces phragmitis (incl. Hippopotamyces gen. nov.) on leaves of Phragmites australis, Lectera philenopterae on Philenoptera violacea, Leptosillia mayteni on leaves of Maytenus heterophylla, Lithohypha aloicola and Neoplatysporoides aloes on leaves of Aloe sp., Millesimomyces rhoicissi (incl. Millesimomyces gen. nov.) on leaves of Rhoicissus digitata, Neodevriesia strelitziicola on leaf litter of Strelitzia nicolai, Neokirramyces syzygii (incl. Neokirramyces gen. nov.) on leaf spots of Syzygium sp., Nothoramichloridium perseae (incl. Nothoramichloridium gen. nov. and Anungitiomycetaceae fam. nov.) on leaves of Persea americana, Paramycosphaerella watsoniae on leaf spots of Watsonia sp., Penicillium cuddlyae from dog food, Podocarpomyces knysnanus (incl. Podocarpomyces gen. nov.) on leaves of Podocarpus falcatus, Pseudocercospora heteropyxidicola on leaf spots of Heteropyxis natalensis, Pseudopenidiella podocarpi, Scolecobasidium podocarpi and Ceramothyrium podocarpicola on leaves of Podocarpus latifolius, Scolecobasidium blechni on leaves of Blechnum capense, Stomiopeltis syzygii on leaves of Syzygium chordatum, Strelitziomyces knysnanus (incl. Strelitziomyces gen. nov.) on leaves of Strelitzia alba, Talaromyces clemensii from rotting wood in goldmine, Verrucocladosporium visseri on Carpobrotus edulis. Spain, Boletopsis mediterraneensis on soil, Calycina cortegadensisi on a living twig of Castanea sativa, Emmonsiellopsis tuberculata in fluvial sediments, Mollisia cortegadensis on dead attached twig of Quercus robur, Psathyrella ovispora on soil, Pseudobeltrania lauri on leaf litter of Laurus azorica, Terfezia dunensis in soil, Tuber lucentum in soil, Venturia submersa on submerged plant debris. Thailand, Cordyceps jakajanicola on cicada nymph, Cordyceps kuiburiensis on spider, Distoseptispora caricis on leaves of Carex sp., Ophiocordyceps khonkaenensis on cicada nymph. USA, Cytosporella juncicola and Davidiellomyces juncicola on culms of Juncus effusus, Monochaetia massachusettsianum from air sample, Neohelicomyces melaleucae and Periconia neobrittanica on leaves of Melaleuca styphelioides × lanceolata, Pseudocamarosporium eucalypti on leaves of Eucalyptus sp., Pseudogymnoascus lindneri from sediment in a mine, Pseudogymnoascus turneri from sediment in a railroad tunnel, Pulchroboletus sclerotiorum on soil, Zygosporium pseudomasonii on leaf of Serenoa repens. Vietnam, Boletus candidissimus and Veloporphyrellus vulpinus on soil. Morphological and culture characteristics are supported by DNA barcodes.

Distinguishing between Structural Models of β'-Sialons Using a Combined Solid-State NMR, Powder XRD, and Computational Approach

β'-Sialons (Si_6-zAl_zO_zN_8-z, where 0 ≤ z ≤ ∼4.2) are studied using a combination of ²⁹Si and ²⁷Al solid-state NMR, using magnetic fields of up to 20 T, powder X-ray diffraction, and density functional theory (DFT) calculations of both the structure and NMR parameters. Four different structural models have been proposed in the literature for the replacement of silicon and nitrogen by aluminum and oxygen within a β-Si₃N₄-structured lattice. Experimental data are presented for the variation with composition (z) of the unit cell parameters from diffraction and the local coordination units present suggested by NMR data. The experimental data are compared to the changes with composition in the DFT calculations of the structure and the NMR parameters according to the four models, allowing the models to be distinguished. It is shown that only one of these, the domain model, is fully consistent with all of the experimental data and is, therefore, a good structural model for β'-sialons. More speculatively, it is suggested that for the domain model, ²⁷Al NMR data might provide a constraint on the thickness of its aluminum-rich layers.

Gular pouch diversity in the Chamaeleonidae

Numerous chameleon species possess an out-pocketing of the trachea known as the gular pouch. After surveying more than 250 specimens, representing nine genera and 44 species, we describe two different morphs of the gular pouch. Species of the genera Bradypodion and Chamaeleo, as well as Trioceros goetzei, all possess a single gular pouch (morph one) formed from ventral expansion of soft tissue where the larynx and trachea meet. Furcifer oustaleti and Furcifer verrucosus possess from one to four gular pouches (morph two) formed by the expansion of soft tissue between sequential hyaline cartilage rings of the trachea. In Trioceros melleri, examples of both morphs of the gular pouch were observed. Morphometric data are presented for 100 animals representing eight species previously known to possess a gular pouch and two additional species, Bradypodion thamnobates and Bradypodion transvaalense. In the species with the absolutely and relatively largest gular pouch, Chamaeleo calyptratus, a significant difference was found between sexes in its width and volume, but not its length. In C. calyptratus, we show that an inflated gular pouch is in contact with numerous hyoid muscles and the tongue. Coupled with the knowledge that C. calyptratus generates vibrations from the throat region, we posit that the tongue (M. accelerator linguae and M. hyoglossus) and supporting hyoid muscles (i.e., Mm. sternohyoideus profundus et superficialis and Mm. mandibulohyoideus) are involved in the production of vibrations to produce biotremors that are amplified by the inflated gular pouch and used in substrate-borne communication.

Anti-Cancer and Ototoxicity Characteristics of the Curcuminoids, CLEFMA and EF24, in Combination with Cisplatin

In this study, we investigated whether the curcuminoids, CLEFMA and EF24, improved cisplatin efficacy and reduced cisplatin ototoxicity. We used the lung cancer cell line, A549, to determine the effects of the curcuminoids and cisplatin on cell viability and several apoptotic signaling mechanisms. Cellular viability was measured using the MTT assay. A scratch assay was used to measure cell migration and fluorescent spectrophotometry to measure reactive oxygen species (ROS) production. Western blots and luminescence assays were used to measure the expression and activity of apoptosis-inducing factor (AIF), caspases-3/7, -8, -9, and -12, c-Jun N-terminal kinases (JNK), mitogen-activated protein kinase (MAPK), and proto-oncogene tyrosine-protein kinase (Src). A zebrafish model was used to evaluate auditory effects. Cisplatin, the curcuminoids, and their combinations had similar effects on cell viability (IC₅₀ values: 2-16 μM) and AIF, caspase-12, JNK, MAPK, and Src expression, while caspase-3/7, -8, and -9 activity was unchanged or decreased. Cisplatin increased ROS yield (1.2-fold), and curcuminoid and combination treatments reduced ROS (0.75-0.85-fold). Combination treatments reduced A549 migration (0.51-0.53-fold). Both curcuminoids reduced auditory threshold shifts induced by cisplatin. In summary, cisplatin and the curcuminoids might cause cell death through AIF and caspase-12. The curcuminoids may potentiate cisplatin's effect against A549 migration, but may counteract cisplatin's effect to increase ROS production. The curcuminoids might also prevent cisplatin ototoxicity.

Anticancer Photodynamic Therapy Properties of Sulfur-Doped Graphene Quantum Dot and Methylene Blue Preparations in MCF-7 Breast Cancer Cell Culture

Photodynamic therapy (PDT) is a field with many applications including chemotherapy. Graphene quantum dots (GQDs) exhibit a variety of unique properties and can be used in PDT to generate singlet oxygen that destroys pathogenic bacteria and cancer cells. The PDT agent, methylene blue (MB), like GQDs, has been successfully exploited to destroy bacteria and cancer cells by increasing reactive oxygen species generation. Recently, combinations of GQDs and MB have been shown to destroy pathogenic bacteria via increased singlet oxygen generation. Here, we performed a spectrophotometric assay to detect and measure the uptake of GQDs, MB and several GQD-MB combinations in MCF-7 breast cancer cells. Then, we used a cell counting method to evaluate the cytotoxicity of GQDs, MB and a 1:1 GQD:MB preparation. Singlet oxygen generation in cells was then detected and measured using singlet oxygen sensor green. The dye, H₂ DCFDA, was used to measure reactive oxygen species production. We found that GQD and MB uptake into MCF-7 cells occurred, but that MB, followed by 1:1 GQD:MB, caused superior cytotoxicity and singlet oxygen and reactive oxygen species generation. Our results suggest that methylene blue's effect against MCF-7 cells is not potentiated by GQDs, either in light or dark conditions.

Balsamia (Sequestrate Helvellaceae, Ascomycota) in western North America

Balsamia, a hypogeous, sequestrate genus in the Helvellaceae, has been characterized variously as having three to eight species in North America, and these have been considered either different from or conspecific with European species. No available modern systematic treatment of Balsamia exists to allow for accurate identification at the species level. We sequenced DNA from recent western North American Balsamia collections, assessed relationships by sequence similarity, and identified molecular taxonomic units. From these data, we determined which matched descriptions and types of named species. ITS sequences supported 12 Balsamia species in western North America, five originally described by Harkness and Fischer and seven new species that we describe here. No sequences from Balsamia collections in western North America were nested among those of European species. We found no clear evidence for separation of Balsamia into multiple genera.

Phylloporus and Phylloboletellus are no longer alone: Phylloporopsis gen. nov. (Boletaceae), a new smooth-spored lamellate genus to accommodate the American species Phylloporus boletinoides

The monotypic genus Phylloporopsis is described as new to science based on Phylloporus boletinoides. This species occurs widely in eastern North America and Central America. It is reported for the first time from a neotropical montane pine woodland in the Dominican Republic. The confirmation of this newly recognised monophyletic genus is supported and molecularly confirmed by phylogenetic inference based on multiple loci (ITS, 28S, TEF1-α, and RPB1). A detailed morphological description of P. boletinoides from the Dominican Republic and Florida (USA) is provided along with colour images of fresh basidiomata in habitat, line drawings of the main anatomical features, transmitted light microscopic images of anatomical features and scanning electron microscope images of basidiospores. The taxonomic placement, ecological requirements and distribution patterns of P. boletinoides are reviewed and the relationships with phylogenetically related or morphologically similar lamellate and boletoid taxa such as Phylloporus, Phylloboletellus, Phyllobolites and Bothia are discussed.

The curcuminoid, EF-24, reduces cisplatin-mediated reactive oxygen species in zebrafish inner ear auditory and vestibular tissues

Cisplatin is a widely used chemotherapy drug that can damage auditory and vestibular tissue and cause hearing and balance loss through the intracellular release of reactive oxygen species (ROS). Curcumin has anticancer efficacy and can also counteract cisplatin's damaging effect against sensory tissue by scavenging intracellular ROS, but curcumin's applicability is limited due to its low bioavailability. EF-24 is a synthetic curcumin analog that is more bioavailable than curcumin and can target cancer, but its effects against cisplatin-mediated ROS in auditory and vestibular tissue is currently unknown. In this study, we employed a novel zebrafish inner ear tissue culture system to determine if EF-24 counteracted cisplatin-mediated ROS release in two sensory endorgans, the saccule and the utricle. The zebrafish saccule is associated with auditory function and the utricle with vestibular function. Trimmed endorgans were placed in tissue culture media with a fluorescent reactive oxygen species indicator dye, and intracellular ROS release was measured using a spectrophotometer. We found that cisplatin treatment significantly increased ROS compared to controls, but that EF-24 treatment did not alter or even decreased ROS. Importantly, when equimolar cisplatin and EF-24 treatments are combined, ROS did not increase compared to controls. This suggests that EF-24 may be able to prevent intracellular ROS caused by cisplatin treatment in inner ear tissue.

Attenuated cocaine-seeking after oxytocin administration in male and female rats

RATIONALE

Initial drug abstinence (modeled here as Extinction Day 1, ED1) is a critical time point in the progression of addiction that is strongly influenced by stress and sex. ED1 induces corticosterone release in both sexes, and cocaine-seeking during ED1 can be mitigated by corticotrophin-releasing factor (CRF) antagonists more effectively in female rats. Oxytocin (OXT) is a neuropeptide that has several biological functions, including regulation of stress pathways.

METHODS

To investigate a relationship between OXT, sex, and cocaine-seeking, we examined Fos on ED1 in OXT neurons of paraventricular (PVN) and supraoptic nuclei (SON) compared to homecage (cocaine experienced) or naïve male and female rats. We also administered OXT 30 min prior to ED1 testing or cued reinstatement testing.

RESULTS

OXT neurons had decreased activity (as reflected by Fos protein) in PVN and SON on withdrawal day 1 (homecage) compared to naïve rats. Fos in OXT neurons was further decreased on ED1, compared to homecage controls, in both males and females even though in SON, cocaine exposure increased the number of OXT-expressing neurons. In addition, systemically administered OXT reduced cocaine-seeking during ED1 and cue-induced reinstatement of cocaine-seeking but delayed extinction, similarly among male and female rats.

CONCLUSIONS

These data indicate that OXT neurons in PVN and SON may be involved in cocaine-seeking during ED1 and support OXT as a possible therapeutic to decrease cocaine-seeking during initial abstinence and in response to cocaine-associated cues.

Anti-cancer characteristics and ototoxicity of platinum(II) amine complexes with only one leaving ligand

Unlike cisplatin, which forms bifunctional DNA adducts, monofunctional platinum(II) complexes bind only one strand of DNA and might target cancer without causing auditory side-effects associated with cisplatin treatment. We synthesized the monofunctional triamine-ligated platinum(II) complexes, Pt(diethylenetriamine)Cl, [Pt(dien)Cl]+, and Pt(N,N-diethyldiethylenetriamine)Cl, [Pt(Et2dien)Cl]+, and the monofunctional heterocyclic-ligated platinum(II) complexes, pyriplatin and phenanthriplatin, and compared their 5'-GMP binding rates, cellular compartmental distribution and cellular viability effects. A zebrafish inner ear model was used to determine if the monofunctional complexes and cisplatin caused hearing threshold shifts and reduced auditory hair cell density. The four monofunctional complexes had varied relative GMP binding rates, but similar cytosolic and nuclear compartmental uptake in three cancer cell lines (A549, Caco2, HTB16) and a control cell line (IMR90). Phenanthriplatin had the strongest effect against cellular viability, comparable to cisplatin, followed by [Pt(Et2dien)Cl]+, pyriplatin and [Pt(dien)Cl]+. Phenanthriplatin also produced the highest hearing threshold shifts followed by [Pt(dien)Cl]+, [Pt(Et2dien)Cl]+, cisplatin and pyriplatin. Hair cell counts taken from four regions of the zebrafish saccule showed that cisplatin significantly reduced hair cell density in three regions and phenanthriplatin in only one region, with the other complexes having no significant effect. Utricular hair cell density was not reduced by any of the compounds. Our results suggest that placing greater steric hindrance cis to one side of the platinum coordinating center in monofunctional complexes promotes efficient targeting of the nuclear compartment and guanosine residues, and may be responsible for reducing cancer cell viability. Also, the monofunctional compounds caused hearing threshold shifts with minimal effect on hair cell density, which suggests that they may affect different pathways than cisplatin.

A novel technology to model pressure-induced cellular injuries in the brain

BACKGROUND

Elevated intracranial pressure (ICP) accompanying a number of neurological emergencies is poorly understood, and lacks a model to determine cellular pathophysiology. This limits our ability to identify cellular and molecular biomarkers associated with the pathological progression from physiologic to pathologic ICP.

NEW METHOD

We developed an ex vivo model of pressure-induced brain injury, which combines 3D neural cell cultures and a newly developed Pressure Controlled Cell Culture Incubator (PC³I). Human astrocytes and neurons maintained in 3D peptide-conjugated alginate hydrogels were subjected to pressures that mimic both physiologic and pathologic levels of ICP for up to 48h to evaluate the earliest impacts of isolated pressure on cellular viability and quantify early indicators of pressure-induced cellular injury.

RESULTS

Compared to control cell cultures grown under physiologic pressure, sustained pathologic pressure exposure increased the release of intracellular ATP in a cell-specific manner. Eighteen hours of sustained pressure resulted in increased ATP release from neurons but not astrocytes.

COMPARISON WITH EXISTING METHODS

Cell culture incubators maintain cultures at normal atmospheric pressure. Based on multiple literature searches, we are not aware of any other cell culture incubator systems that modify the pressure at which primary CNS cells are maintained.

CONCLUSION

This model simulates the clinical features of elevated ICP encountered in patients with hydrocephalus, and provides a first estimate of the pathological signaling encountered during the earliest perid of progression in neonatal hydrocephalus. This model should provide a means to better understand the pathological biomarkers associated with the earliest stages of elevated ICP.

Greater post-Neolithic wealth disparities in Eurasia than in North America and Mesoamerica

How wealth is distributed among households provides insight into the fundamental characters of societies and the opportunities they afford for social mobility. However, economic inequality has been hard to study in ancient societies for which we do not have written records, which adds to the challenge of placing current wealth disparities into a long-term perspective. Although various archaeological proxies for wealth, such as burial goods or exotic or expensive-to-manufacture goods in household assemblages, have been proposed, the first is not clearly connected with households, and the second is confounded by abandonment mode and other factors. As a result, numerous questions remain concerning the growth of wealth disparities, including their connection to the development of domesticated plants and animals and to increases in sociopolitical scale. Here we show that wealth disparities generally increased with the domestication of plants and animals and with increased sociopolitical scale, using Gini coefficients computed over the single consistent proxy of house-size distributions. However, unexpected differences in the responses of societies to these factors in North America and Mesoamerica, and in Eurasia, became evident after the end of the Neolithic period. We argue that the generally higher wealth disparities identified in post-Neolithic Eurasia were initially due to the greater availability of large mammals that could be domesticated, because they allowed more profitable agricultural extensification, and also eventually led to the development of a mounted warrior elite able to expand polities (political units that cohere via identity, ability to mobilize resources, or governance) to sizes that were not possible in North America and Mesoamerica before the arrival of Europeans. We anticipate that this analysis will stimulate other work to enlarge this sample to include societies in South America, Africa, South Asia and Oceania that were under-sampled or not included in this study.

Cross-Modal Repetition Effects on the N4

Event related brain potentials (ERP) were recorded from 12 normal right-handed subjects from 13 midline and lateral scalp sites during a task that involved learning a list of 20 words in the auditory modality, followed by recognition memory testing in first the auditory and then the visual modality. Subjects were instructed to keypress to repeated words, which were randomly mixed with an equal number of novel distractor words. A decrement in the amplitude of the N4 component of ERPs and an increase in the P3 component was found following repeated words in the auditory condition, and this difference persisted across modalities to the visual condition, although the anterior-posterior distribution of the N4 difference changed between conditions. The cross-modal transfer of the repetition-induced N4 attenuation suggests that the N4 change may be modulated by a semantic (i.e., non-modality specific) memory trace, while the difference in its distribution between the auditory and visual conditions provides evidence for a modality-specific contribution to the N4 generator.

Management of pinna haematoma study (MaPHaeS): A multicentre retrospective observational study

OBJECTIVES

To assess current variation in the management of pinna haematoma (PH) and its effect on outcomes.

DESIGN

Multicentre retrospective observational record-based study.

SETTING

Eleven hospitals around the UK.

PARTICIPANTS

Eighty-three patients above the age of 16 with PH.

OUTCOME MEASURES

The primary outcome measure was recurrence rate of PH over a 6-month period post-treatment, assessed by treatment type (scalpel incision vs needle aspiration). Secondary outcome measures assessed the impact of other factors on recurrence, infection and cosmetic complications of PH over a period of 6 months.

RESULTS

After adjusting for confounding factors, involvement of the whole ear, and management within an operating theatre were associated with a lower rate of recurrence of pinna haematoma. The drainage technique, suspected aetiology, choice of post-drainage management, grade and specialty of practitioner performing drainage, the use of antibiotic cover and hospital admission did not affect the rate of haematoma recurrence, infection or cosmetic complications.

CONCLUSIONS

Where possible PH should be drained in an operating theatre. Multicentre randomized controlled trials are required to further investigate the impact of drainage technique and post-drainage management on outcome.

Population-Area Relationship for Medieval European Cities

Medieval European urbanization presents a line of continuity between earlier cities and modern European urban systems. Yet, many of the spatial, political and economic features of medieval European cities were particular to the Middle Ages, and subsequently changed over the Early Modern Period and Industrial Revolution. There is a long tradition of demographic studies estimating the population sizes of medieval European cities, and comparative analyses of these data have shed much light on the long-term evolution of urban systems. However, the next step-to systematically relate the population size of these cities to their spatial and socioeconomic characteristics-has seldom been taken. This raises a series of interesting questions, as both modern and ancient cities have been observed to obey area-population relationships predicted by settlement scaling theory. To address these questions, we analyze a new dataset for the settled area and population of 173 European cities from the early fourteenth century to determine the relationship between population and settled area. To interpret this data, we develop two related models that lead to differing predictions regarding the quantitative form of the population-area relationship, depending on the level of social mixing present in these cities. Our empirical estimates of model parameters show a strong densification of cities with city population size, consistent with patterns in contemporary cities. Although social life in medieval Europe was orchestrated by hierarchical institutions (e.g., guilds, church, municipal organizations), our results show no statistically significant influence of these institutions on agglomeration effects. The similarities between the empirical patterns of settlement relating area to population observed here support the hypothesis that cities throughout history share common principles of organization that self-consistently relate their socioeconomic networks to structured urban spaces.

The Transcriptomics to Proteomics of Hair Cell Regeneration: Looking for a Hair Cell in a Haystack

Mature mammals exhibit very limited capacity for regeneration of auditory hair cells, while all non-mammalian vertebrates examined can regenerate them. In an effort to find therapeutic targets for deafness and balance disorders, scientists have examined gene expression patterns in auditory tissues under different developmental and experimental conditions. Microarray technology has allowed the large-scale study of gene expression profiles (transcriptomics) at whole-genome levels, but since mRNA expression does not necessarily correlate with protein expression, other methods, such as microRNA analysis and proteomics, are needed to better understand the process of hair cell regeneration. These technologies and some of the results of them are discussed in this review. Although there is a considerable amount of variability found between studies owing to different species, tissues and treatments, there is some concordance between cellular pathways important for hair cell regeneration. Since gene expression and proteomics data is now commonly submitted to centralized online databases, meta-analyses of these data may provide a better picture of pathways that are common to the process of hair cell regeneration and lead to potential therapeutics. Indeed, some of the proteins found to be regulated in the inner ear of animal models (e.g., IGF-1) have now gone through human clinical trials.

Assignment of gender to French nouns in primary and secondary language : a connectionist model

In French, grammatical gender is often represented phonologically and/or morphologically. Thus, a language learner's competence for gender iden tification might in part reflect the ability to recognize patterns in noun phonology and morphology. We herein describe a computer-based connec tionist-type network model which learned to identify correctly the gender of a set of French nouns. Subsequently, this model was able to generalize from that learning experience and assign gender to previously unstudied nouns with a high degree of reliability. This gender assignment was accomplished by relying solely upon information inherent in the structure of the nouns themselves, and it occurred in the absence of explicit rules for the evaluation of nouns. Instead, the model discovered criterial gender-specific features when shown examples of masculine and feminine nouns during its initial training period. The model's ability to learn these gender-specific features was found to be related both to its initial connectivity state and to a variable learning-rate parameter. These latter results are discussed with respect to their general implications for second language learning.

Another Road to Evaluating Knowledge Assets

Human Resource Development (HRD) practitioners can earn a fresh endorsement from new methods of assessing the value of knowledge assets in companies they serve. Successful HRD practice depends on decisions made by managers who focus on proven financial performance. The economic theory that supports HRD practice is concerned with the value added to companies through personnel training and development and organization development. Accounting and economics professionals are suggesting new approaches to measuring and reporting the value of intellectual capital in for-profit companies. These methods provide ways to measure HRD’s contribution to the firm at the organization level. This article describes new methods of measuring the value of intellectual capital and recommends improvements in the valuation of intellectual capital.

Causes and Consequences of Sensory Hair Cell Damage and Recovery in Fishes

Sensory hair cells are the mechanotransductive receptors that detect gravity, sound, and vibration in all vertebrates. Damage to these sensitive receptors often results in deficits in vestibular function and hearing. There are currently two main reasons for studying the process of hair cell loss in fishes. First, fishes, like other non-mammalian vertebrates, have the ability to regenerate hair cells that have been damaged or lost via exposure to ototoxic chemicals or acoustic overstimulation. Thus, they are used as a biomedical model to understand the process of hair cell death and regeneration and find therapeutics that treat or prevent human hearing loss. Secondly, scientists and governmental natural resource managers are concerned about the potential effects of intense anthropogenic sounds on aquatic organisms, including fishes. Dr. Arthur N. Popper and his students, postdocs and research associates have performed pioneering experiments in both of these lines of fish hearing research. This review will discuss the current knowledge regarding the causes and consequences of both lateral line and inner ear hair cell damage in teleost fishes.