Electrogenic Ion Pumps Investigated on a Solid Supported Membrane: Comparison of Current and Voltage Measurements

Current and voltage measurements were performed on Na,K-ATPase and sarcoplasmic reticulum (SR) Ca-ATPase. Measurements of current transients under short-circuit conditions and of voltage transients under open-circuit conditions were carried out by employing a solid supported membrane (SSM). Purified membrane fragments containing Na,K-ATPase or native SR vesicles were adsorbed on a SSM and were activated by performing substrate concentration jumps. Current and voltage transients were recorded in the external circuit, that are related to pump activity, and can be attributed to electrogenic events in the reaction cycles of the two enzymes. While current transients of very small amplitude are difficult to detect, the corresponding voltage transients can be measured with higher accuracy thanks to a much more favourable signal to noise ratio. Therefore, voltage measurements are preferable for the investigation of slow processes generating low current signals, e.g. for the analysis of low turnover transporters

Dati preliminari sull’uso dello spazio e sui ritmi di attività dei mustelidi in Italia Centrale.

In Italia le informazioni sulla biologia dei mustelidi sono ancora scarse e frammentate. Nella presente ricerca, avviata nel 2005, ci si propone di ampliare le conoscenze sulla presenza, densità, genetica e ecologia di base (dieta e uso dello spazio) dei mustelidi in alcuni ambienti della Toscana Centrale. Sono presentati i dati, raccolti a partire dall’agosto 2005, relativi all’uso dello spazio e ai ritmi di attività di 2 martore (Martes martes L.) e 2 tassi (Meles meles L.). L’area di studio, nel Comune di Radicondoli in Provincia di Siena, è caratterizzata da ampie foreste termofile di cerro, alternate a campi aperti destinati a seminativo, con una rete di fossi, fiumi e laghi artificiali. Gli animali sono stati catturati in trappole costruite secondo il modello di Havahart, marcati con “Passive Integrated Transponder” (PIT) sottocutanei per il riconoscimento individuale e muniti di radiocollare. Sono stati inoltre effettuati prelievi di campioni biologici da destinare alle analisi genetiche. Il monitoraggio radiotelemetrico è stato eseguito su base giornaliera, in modo da ricoprire l’arco delle 24h in una settimana. Gli animali sono stati localizzati utilizzando la tecnica della triangolazione. Durante le sessioni di radiotelemetria sono stati registrati i principali parametri ambientali, mentre per l’analisi dell’uso dello spazio sono state utilizzate carte topografiche 1:25000 e ortofoto della CGR scala 1:50000. Gli “home range” sono stati calcolati a livello stagionale con il metodo del kernel al 95, 75, 50%. I ritmi di attività sono stati analizzati dividendo le 24h in fasce orarie di 4h ciascuna. Sino ad ora sono state raccolte circa 300 localizzazioni per la martora e 700 per il tasso. Il tasso è risultato occupare un “home range” estivo più ampio di circa tre volte rispetto a quello invernale, con attività prevalentemente notturna (95% delle localizzazioni) e brevi periodi di semiletargia nei mesi più freddi. La martora ha occupato un “home range” estivo più ampio di circa il doppio rispetto a quello invernale, mostrando un’attività notturna pari al 63% delle localizzazioni. Questi risultati preliminari confermano quanto già riportato in letteratura e costituiscono il primo passo di una ricerca a lungo termine sui mustelidi della Toscana centrale

Activity patterns of the Pine marten (Martes martes) in a Mediterranean woodland: evaluation of preliminary data.

Two pine martens Martes martes, a male and a female, were radio-tracked (six and eleven months respectively) in a forest area near Siena, Central Italy. Martens were captured using box traps baited with eggs and mice, marked by Passive Integrated Transponders (PITs) and fitted with a VHF radio-collar (Televilt, 60 g.). Individuals were monitored daily and fixes were collected to provide data for a 24 hour period within each week. During the radio-tracking sessions environmental parameters (temperature, humidity, pressure, precipitation and moon phase) were also collected. The activity pattern was correlated with the environmental factors by Logistic Regression procedure. Nocturnal, diurnal and crepuscular activities were measured as the proportion of active fixes for each phases. Activity differed between seasons and was mainly influenced by the environmental temperature. Martens usually perform nocturnal activity. However, our data showed also a not negligible activity carried out during the day. Diurnal and nocturnal patterns of activity were compared

Habitat selection of European pine marten in Central Italy: from a tree dependent to a generalist species

Studies at small spatial scale are often fundamental to highlight the behavioural plasticity of a species and thus have important implications for conservation planning, in particular for species usually considered as habitat specialists. We investigated second-order habitat selection of the European pine marten in an area dominated by deciduous oak forest and open fields in central Italy, by radio-tracking 16 pine martens (eight males, eight females). Pine martens placed home ranges in areas with more open field than in the study area, whereas woodland (oak and conifer forests) comprised a smaller portion of the home range than predominant forest character of the studied area. Although the presence of the species in the open habitats has been documented, to our knowledge, our results provide the first evidence of home range establishment in this cover type by pine marten at population level. The combination of low predation risk and high availability of resources could allow pine martens to occupy open fields in our study area. We highlighted different individual strategies of habitat selection, with some individuals placing home ranges in areas with high forest coverage while others occupying open areas. We found no effects of sex and body condition on habitat selection, and this could indicate that in the study area, both forested and non-forested cover types, such as open fields, shrub and anthropic areas, can provide adequate food, overhead cover and resting sites for all individuals. Pine marten ability to occupy open fields seems thus more related to the behavioural flexibility of the species, rather than to the need to supplement dens and forage from complementary lower quality habitat. The high quality of the Mediterranean continental area studied could also explain the selection of open areas by the pine marten. Our results offer useful information on pine marten ecology and may be helpful for conservation management of this species in southern Europe

Nestin expression in normal adrenal gland and adrenocortical tumors

Human adrenocortical cells have been shown to express cytokeratins and vimentin. Nestin is an intermediate filament protein that is mainly expressed in the developing nervous system and that has been recently reported in rat adrenal gland as well. Using immunohistochemical and biochemical approaches, the present study demonstrates that nestin is constantly expressed in situ in the cortex of normal human adrenal glands. Nestin expressing cells were prevalently located in the zona reticularis but some positive cells could be spotted in the zona fasciculata as well. Moreover, patches of nestin-positive cells have been constantly detected on sections of cortical adenomas. In contrast, adrenal carcinomas displayed a variable number of nestin-immunoreactive cells that in some cases were virtually absent. Samples of renal clear cell carcinoma metastasis in the adrenals were also examined which did not show nestin-immunoreactivity. We propose that a positive nestin-immunoreaction could be useful in differential diagnosis of clear cell tumors in adrenal glands

Translocation of Platinum Anticancer Drugs by Human Copper ATPases ATP7A and ATP7B

Cisplatin, carboplatin, and oxaliplatin are widely used anticancer drugs. Their efficacy is strongly reduced by development of cell resistance. Down-regulation of CTR1 and up-regulation of the Cu-ATPases, ATP7A and ATP7B, have been associated to augmented drug resistance. To gain information on translocation of Pt drugs by human Cu-ATPases, we performed electrical measurements on the COS-1 cell microsomal fraction, enriched with recombinant ATP7A, ATP7B, and selected mutants, and adsorbed on a solid supported membrane. The experimental results indicate that Pt drugs activate Cu-ATPases and undergo ATP-dependent translocation in a fashion similar to that of Cu. We then used NMR spectroscopy and ESI-MS to determine the binding mode of these drugs to the first N-terminal metal-binding domain of ATP7A (Mnk1)

Retroperitoneal seminoma secondary to 'burned out' testicular tumor in an acromegalic patient

Abstract We report a case of an acromegalic patient with a retroperitoneal seminoma secondary to a testicular tumor which had completely disappeared. Testicular ultrasonography did not show any pathological mass and histological examination indicated that the normal testis had been totally replaced by fibrous tissue, without neoplastic cells. Our patient had high levels of growth hormone (GH) and prolactin (PRL), both hormones with high immunostimulating effect, and an increase of interleukin-2 receptor-positive lymphocytes, a finding supporting enhanced immunological activity. Thus, we cannot exclude that the immunological pattern of this acromegalic patient may have played some role in the tumoral destructio