University of Cagliari

About: University of Cagliari is a education organization based out in Cagliari, Italy. It is known for research contribution in the topics: Population & Dopamine. The organization has 11029 authors who have published 29046 publications receiving 771023 citations. The organization is also known as: Università degli Studi di Cagliari & Universita degli Studi di Cagliari.

Long-lasting memory t cell responses following self-limited acute hepatitis b

Abstract: The molecular and cellular basis of long-term T cell mem- ory against viral antigens is still largely undefined. To char- acterize anti-viral protection by memory T cells against non-cytopathic viruses able to cause acute self-limited and chronic infections, such as the hepatitis B virus (HBV), we studied HLA class II restricted responses against HBV struc- tural antigens in 17 patients with acute hepatitis B, during the acute stage of infection and 2.2 to 13 yr after clinical resolu- tion of disease. Results indicate that: (a) significant T cell proliferative responses to HBV nucleocapsid antigens were detectable in all patients during the acute phase of infection and in 14/17 also 2-13 yr after clinical resolution of disease; b) long-lasting T cell responses were sustained by CD45RO 1 T cells, predominantly expressing the phenotype of recently activated cells; c) limiting dilution analysis showed that in some patients the frequency of HBV-specific T cells was comparable to that observed in the acute stage of infection and, usually, higher than in patients with chronic HBV in- fection; d) the same amino acid sequences were recognized by T cells in the acute and recovery phases of infection; and e) HBV-DNA was detectable by nested-PCR in approxi- mately half of the subjects. In conclusion, our results show that vigorous anti-viral T cell responses are detectable in vitro several years after clin- ical recovery from acute hepatitis B. Detection of minute amounts of virus in some recovered subjects suggests that long-term maintenance of an active anti-viral T cell re- sponse could be important not only for protection against reinfection but also for keeping the persisting virus under tight control. ( J. Clin. Invest. 1996. 98:1185-1194.) Key words: viremiacytokinestetanustoxoidHBV nucleo- capsid antigensHBV envelope antigens

The High Time Resolution Universe Pulsar Survey – I. System configuration and initial discoveries

Abstract: We have embarked on a survey for pulsars and fast transients using the 13-beam multibeam receiver on the Parkes Radio Telescope Installation of a digital backend allows us to record 400 MHz of bandwidth for each beam, split into 1024 channels and sampled every 64 μs Limits of the receiver package restrict us to a 340 MHz observing band centred at 1352 MHz The factor of 8 improvement in frequency resolution over previous multibeam surveys allows us to probe deeper into the Galactic plane for short-duration signals such as the pulses from millisecond pulsars We plan to survey the entire southern sky in 42 641 pointings, split into low, mid and high Galactic latitude regions, with integration times of 4200, 540 and 270 s, respectively Simulations suggest that we will discover 400 pulsars, of which 75 will be millisecond pulsars With ∼30 per cent of the mid-latitude survey complete, we have redetected 223 previously known pulsars and discovered 27 pulsars, five of which are millisecond pulsars The newly discovered millisecond pulsars tend to have larger dispersion measures than those discovered in previous surveys, as expected from the improved time and frequency resolution of our instrument