Biomedical subjects

S Polo

Publications and source records attributed to S Polo.

23 records · Page 2Linked to original sources

PubMed1997

[Profound venous thrombosis and popliteal cyst: problems of differential diagnosis relative to the use of phleboscintigraphy. Description of a clinical case].

The following is the case report of M. G. a 68-year-old male carrier of polcythemia vera, a pathology in which the risk of thrombosis is increased. The patient presented clinically suspected deep venous thrombosis and a phleboscintigraphy confirmed the diagnosis. A real-time B-mode ultrasonography performed later instead demonstrated a popliteal cyst. The case report focuses on diagnostic methods in deep venous thrombosis and particular attention is paid to the role of phleboscintigraphy, of impedance plethysmography and of real time B-mode ultrasonography.

Aged↗

PubMed1996

Identification of a phage-coded DNA-binding protein that regulates transcription from late promoters in bacteriophage P4.

The genetic element P4 can propagate as a temperate phage or as a multicopy plasmid in its host Escherichia coli. Late in the lytic cycle and in the plasmid condition, transcription of the P4 essential genes depends on the activation of the late promoters P(LL) and P(sid), which control the transcription of the left and right operons, respectively. Both P4 late promoters are positively regulated by the product of the P4 delta gene, which is transcribed from P(sid). We have identified a new P4 gene, vis, that appears to play a relevant role in P4 late transcription control. vis is the first gene downstream of P(LL) and codes for a basic 88 amino acid protein with a potential helix-turn-helix motif. Expression of the cloned vis gene suppresses all the phenotypic traits exhibited by P4 vir1, a mutant that carries a promoter-up mutation in the late promoter P(LL). By Northern hybridization analysis we showed that vis negatively regulates transcription from P(LL) and enhances transcription from P(sid). Thus, vis auto-regulates its expression by repressing its own promoter and enhancing transcription of delta, which is required for P(LL) activation. The vis gene was fused with the glutathione S-transferase gene and the GST-Vis fusion protein was partially purified. By gel retardation assays and DNA footprinting we demonstrated that GST-Vis binds to a 32 bp long region immediately downstream of P(LL). We also showed, by gel retardation, that GST-Vis binds to the P sid region. A sequence present in both P(LL) and P(sid) regions may represent the Vis binding consensus sequence. The dual role of Vis on the control of P4 late transcription may be required for a regulated expression of the replication functions when P4 propagates in the plasmid state.

Amino Acid Sequence↗

PubMed1995

Multiple regulatory mechanisms controlling phage-plasmid P4 propagation.

Bacteriophage P4 autonomous replication may result in the lytic cycle or in plasmid maintenance, depending, respectively, on the presence or absence of the helper phage P2 genome in the Escherichia coli host cell. Alternatively, P4 may lysogenize the bacterial host and be maintained in an immune-integrated condition. A key step in the choice between the lytic/plasmid vs. the lysogenic condition is the regulation of P4 alpha operon. This operon may be transcribed from two promoters, PLE and PLL, and encodes both immunity (promoter proximal) and replication (promoter distal) functions. PLE is a constitutive promoter and transcription of the downstream replication genes is regulated by transcription termination. The trans-acting immunity factor that controls premature transcription termination is a short RNA encoded in the PLE proximal part of the operon. Expression of the replication functions in the lytic/plasmid condition is achieved by activation of the PLL promoter. Transcription from PLL is insensitive to the termination mechanism that acts on transcription starting from PLE.PLL is also negatively regulated by P4 orf88, the first gene downstream of PLL. An additional control on P4 DNA replication is exerted by the P4 cnr gene product.

Bacteriophage P1↗

PubMedDate not supplied

Incidence of hepatocellular carcinoma in Italy: what could we learn from autoptic studies?

From January 1, 1968 to December 31, 1984, 31,955 autopsies were performed at the Department of Pathology of the University of Trieste. Of these 16,521 were male and 15,434 female which covered about 70% of the population who died in the area over the recent years. Hepatocellular carcinoma (HCC) associated with liver cirrhosis was encountered in 441 cases (380 males and 61 females, M:F ratio 5.8:1) with an overall occurrence of 1.4% in the autoptic population. On the contrary and in the absence of chronic liver disease HCC was only observed in 0.3% of the cases (45 males and 16 females, M:F ratio 2.7:1). Liver cirrhosis accounted for 10% of autopsies (2099 males and 1104 females, M:F ratio 1.8:1). A 15% of cirrhosis was associated with HCC, indicating that major attention should be paid to cirrhotic patients, in particular males after the 5th decade of life. The year distribution of HCC and cirrhosis was fairly constant during the period of time considered. These data suggest that: i) HCC is common in Italy; ii) in the vast majority, HCC occurs in the presence of cirrhosis; and iii) HCC appears to be a rather late disease as it does not reduce the life expectancy of cirrhotic and control populations. Since reliable, nationwide epidemiological data are not available in Italy, it is not known whether these data represent a local realty or whether they may be extrapolated to the entire country. Cooperative and prospective studies appear appropriate in investigating possible geographical differences in HCC distribution and permit a better understanding and prevention of the disease.

Adult↗

PubMedDate not supplied

Increased plasma levels of the C-C chemokine RANTES in patients with primary HIV-1 infection.

To investigate the role played by chemokines in the natural history of human immunodeficiency virus (HIV) infection, we measured the plasma levels of RANTES. MIP-1 alpha and MIP-1 beta in a cohort of patients with primary HIV-1 infection (PHI) followed longitudinally. The cohort included 17 patients with well-documented history of acute HIV syndrome within two months of the first observation. The mean plasma concentration of RANTES, but not that of MIP-1 alpha or MIP-1 beta, was significantly higher in patients with PHI (192.3 ng/ml) than in five HIV-seronegative controls (8.0 ng/ml) studied during the same time period. Treatment of blood with a cocktail of drugs preventing platelet activation, followed by high-speed centrifugation, reduced the levels of RANTES by approximately 2 logs both in patients and in controls, indicating that the bulk of RANTES was released by platelets, which are known to store this chemokine in their alpha-granules, in the immediate aftermath of blood drawing. No correlation was seen between the levels of RANTES and the number of HIV genome equivalents in plasma. These data suggest that large amounts of pre-formed RANTES are stored in platelets and, possibly, in other blood cells during the early phases of HIV infection. The possible role of this HIV-suppressive chemokine in the control of viral replication during PHI remains to be established.

Chemokine CCL5↗