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Biomedical subjects

M Serrano

Publications and source records attributed to M Serrano.

At least 19 recordsLinked to original sources
PubMed1992

DNA conformational change induced by the bacteriophage phi 29 connector.

Translocation of viral DNA inwards and outwards of the capsid of double-stranded DNA bacteriophages occurs through the connector, a key viral structure that is known to interact with DNA. It is shown here that phage phi 29 connector binds both linear and circular double-stranded DNA. However, DNA-mediated protection of phi 29 connectors against Staphylococcus aureus endoprotease V8 digestion suggests that binding to linear DNA is more stable than to circular DNA. Endoprotease V8-protection assays also suggest that the length of the linear DNA required to produce a stable phi 29 connector-DNA interaction is, at least, twice longer than the phi 29 connector channel. This result is confirmed by experiments of phi 29 connector-protection of DNA against DNase I digestion. Furthermore, DNA circularization assays indicate that phi 29 connectors restrain negative supercoiling when bound to linear DNA. This DNA conformational change is not observed upon binding to circular DNA and it could reflect the existence of some left-handed DNA coiling or DNA untwisting inside of the phi 29 connector channel.

Bacillus Phages↗
PubMed1992

[Detection of hepatitis B virus DNA in serum by gene amplification in patients with chronic hepatitis B and in patients chronic hepatitis C].

BACKGROUND: The polymerase chain reaction (PCR) constitutes important methodological progress for detecting the presence of viral nucleic acids when these are found in small quantities in serum or tissues. The aim of this study was the use of PCR to detect DNA of the hepatitis B virus (HBV) in patients with chronic HBsAg positive hepatitis (HC-B) and in patients with chronic non A non B hepatitis with antibodies against the virus of hepatitis C (anti-HCV) positive (HC-C). METHODS: The DNA of the HBV was determined with PCR in the serum of 40 patients with HC-B and in 15 with HC-C. Moreover, the presence of anti-HCV was studied in the patients with HC-B. RESULTS: The presence of DNA of the HBV was detected by PCR in 69% of the HC-B patients presenting HBeAg positive and DNA of the HBV negative by simple hybridization as well as in 50% of the patients with HBeAg negative, anti-HBe positive and DNA of HBV negative by simple hybridization. In addition, DNA of HBV was detected by PCR in 27% (4/15) of the subjects with HC-C, three of whom had anti-HBc antibodies. On the other hand, 20% of the patients with HC-B had anti-HCV. Anti-HCV positivity was associated to a greater hypertransaminasemia in patients with HC-B in a non replicative phase. CONCLUSIONS: PCR is a sensitive method for detecting viral replication. Its use permits the detection of low DNA concentrations of the HBV in a low but appreciable percentage of chronic negative HBsAg hepatitis. Coinfection by the B and C viruses of hepatitis is not exceptional and explains hypertransaminasemia in some HC-B in a non replicative phase.

DNA, Viral↗
PubMed1992

[Value of fine needle aspiration cytology in the diagnosis and treatment of tumors].

UNLABELLED: We report the cytologic results of 186 fine needle aspirations on accessible lymph nodes and tumoral masses as well as deep masses under radiologic control. We assessed the ratios of diagnostic accuracy and the utility of this procedure for staging solid tumors and taking therapeutic decisions. RESULTS: sensitivity, 89.6%; specificity, 100%; positive predictive value, 100%; negative predictive value, 57% and accuracy index, 89.2%. Using this technique we detected a metastatic disease in 62% of neoplastic patients. We took a therapeutic decision (active treatment or analgesia) in accordance with the results of the cytology in 63% of patients with solid tumors. Two patients, after a transthoracic aspiration, developed pneumothorax as a complication. Cytology by fine needle aspiration is a fast and simple method for diagnosing, staging and taking a therapeutic decision on patients with solid tumors.

Adult↗
PubMed1991

[The treatment of large-cell non-Hodgkin's lymphomas with the MACOP-B protocol].

BACKGROUND: To investigate the results of the treatment of large-cell non-Hodgkin's lymphomas (LCNHL) with the MACOP-B chemotherapy protocol. METHODS: 20 patients with the following inclusion criteria were treated: LCNHL with a definite majority of large lymphoid cells and absence of previous therapy, HIV infection or severe underlying diseases. RESULTS: Three patients died during therapy and 15 (75%) achieved a complete remission. Actuarial survival after 36 months (0.66) was significantly better (p = 0.05) than that of a comparable historical series of LCNHL treated with CHOP (0.28). Age, stages III-IV, B symptoms, large lymphatic mass (LLM) and bone marrow infiltration did not negatively affect survival. The toxicity of the MACOP-B protocol was high: mucositis (65%), cytopenia (55%), neuropathy (40%), complications of steroid therapy (15%), and mortality directly related with therapy in 15%. Residual masses were found after therapy in 7% (70%) with BD, which were localized in lymphoid areas or in parenchyma (spleen and kidney). Surgical exploration showed that the residual masses were not tumoral in three cases, and in another three magnetic resonance suggested inactive disease. CONCLUSIONS: The MACOP-B protocol is highly effective for the treatment of LCNHL. The essential prognostic factor for survival in these NHL appears to be the cell composition with a great majority of large cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Transcription activation at a distance by phage phi 29 protein p4. Effect of bent and non-bent intervening DNA sequences.

Protein p4 of the Bacillus subtilis phage phi 29 switches on the transcription of the viral late genes by binding to the viral late promoter at a region close to the RNA polymerase binding site. Gel retardation and DNase I footprinting assays show that the presence of protein p4 is required for RNA polymerase recognition of the late promoter. The protein p4 and RNA polymerase DNA binding sites have been separated by the insertion of bent and non-bent DNA sequences of different lengths. These mutant promoters were used to study in vitro their protein p4-dependent transcriptional activity and their interaction with both protein p4 and RNA polymerase. The results indicate that protein p4 is able to function at longer DNA distances from the RNA polymerase binding site than in the natural promoter. The extent of protein p4 activity depended on the length and conformation of the inserted DNA. Activation of transcription and RNA polymerase binding was favoured when the relative orientation of protein p4 and RNA polymerase was conserved and when the intervening DNA had a bent conformation. These data, together with the DNase I footprints, suggest that activation at distance by protein p4 involves a DNA loop held by the interaction of protein p4 and RNA polymerase.

Bacillus subtilis↗
PubMed1991

Contamination and radiation exposure from 201Tl in patients undergoing dialysis after a nuclear medicine study.

Our institution is a major kidney research and transplant center. Hemodialysis patients that are scheduled for renal transplant are given a 201Tl stress test. Possible radiation exposure and contamination are of concern to attending personnel. We investigated this situation and found measurable activity in the effluent of patients receiving dialysis but no significant contamination of equipment. We determined that dialysis personnel received minimal radiation exposure.

Equipment Contamination↗
PubMed1990

Characterization of a DNA binding protein of bacteriophage PRD1 involved in DNA replication.

Escherichia coli phage PRD1 protein P12, involved in PRD1 DNA replication in vivo, has been highly purified from E. coli cells harbouring a gene XII-containing plasmid. Protein P12 binds to single-stranded DNA as shown by gel retardation assays and nuclease protection experiments. Binding of protein P12 to single-stranded DNA increases about 14% the contour length of the DNA as revealed by electron microscopy. Binding to single-stranded DNA seems to be cooperative, and it is not sequence specific. Protein P12 also binds to double-stranded DNA although with an affinity 10 times lower than to single-stranded DNA. Using the in vitro phage phi 29 DNA replication system, it is shown that protein P12 stimulates the overall phi 29 DNA replication.

Coliphages↗
PubMed1990

Types 1 and 2 plasminogen activator inhibitor and tumor necrosis factor alpha in patients with sepsis.

We have determined the plasma concentrations of types 1 and 2 of plasminogen activator inhibitor (PAI-1 and PAI-2), tumor necrosis factor (TNF-alpha) and endotoxin in 47 patients with bacterial infection (22 patients presented with positive blood cultures). Results were compared with those observed in 30 healthy subjects. There was a significant increase in PAI-1 and TNF-alpha in patients as compared to controls (p less than 0.0001), whereas no differences for PAI-2 were observed. PAI-1 and TNF-alpha were significantly higher in 18 patients with gram-negative bacteremia as compared to all other patients (p less than 0.0001). However, no correlation between the analyzed parameters and either endotoxin or clinical outcome was observed. We conclude that there is an increase of PAI-1 and TNF-alpha in patients with sepsis, which is not related to the endotoxin concentration. Our results suggest that PAI-1, but not PAI-2, is the main plasminogen activator inhibitor in human sepsis.

Adolescent↗
PubMed1990

A novel nucleoprotein complex at a replication origin.

The viral protein p6, required for the protein-primed initiation of replication of Bacillus subtilis phage phi 29, forms a nucleoprotein complex at the viral replication origins that shows novel features. Deoxyribonuclease I and hydroxyl radical footprinting data, as well as the induction of positive supercoiling, support a model in which a DNA right-handed superhelix tightly wraps around a multimeric p6 core. The interaction occurs through the DNA minor groove. The activity of p6 not only requires the formation of the complex but also its correct positioning, indicating that the other proteins involved in the initiation of replication recognize, at a precise position, either the p6 core or the DNA conformational change induced by p6.

Bacillus subtilis↗
PubMed1990

Hodgkin's disease in patients with antibodies to human immunodeficiency virus. A study of 22 patients.

The experience of 22 Hodgkin's disease (HD) patients with human immunodeficiency virus type I (HIV) antibodies, collected from a cooperative study of six hospitals during 1984-1989 is presented. Young men (average age, 27.6 years) with a high incidence of intravenous drug abuse (86%) were found. The status of the HIV infection at diagnosis of HD was: four patients, acquired immune deficiency syndrome (AIDS); eight patients, persistent generalized lymphadenopathy (PGL); and ten patients, asymptomatic. The natural history of HD was unusual, with a high incidence of B symptoms (81%), advanced Stages III to IV (90%), bone marrow invasion (50%), cytopenias before treatment (45%), opportunistic infections (68%), and aggressive histologies. A decreased response to chemotherapy with poor marrow tolerance and a significant decrease in survival, 18 months, was observed. The AIDS and cytopenias pretreatment were associated with a shorter statistically significant survival, which defines the importance of immunodeficiency in HD prognosis. Complete remission after treatment was a factor that contributed to a longer statistically significant survival. The PGL or asymptomatic patients survived longer but also had a poor course, and five of them had AIDS criteria during evolution. A high incidence of HD in relation to non-Hodgkin's lymphoma (NHL) in patients with HIV infection in the six cooperating hospitals was found. Criteria for considering HD as an AIDS-associated lymphoproliferative disease in our environment are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Monocyte disorder causing cellular immunodeficiency: a family study.

We report a familial type of monocyte dysfunction not recognized previously. This disorder was observed in a young adult man with a long clinical history of recurrent, self-limited episodes of cryptogenic fever accompanied by digestive and respiratory symptoms and repeated oral and skin infections. Lectin-induced lymphocyte transformation was reduced and skin tests revealed anergy to tuberculin and candidin. Monocytes from this patient exhibited markedly diminished expression of cytoskeletal vimentin intermediate filaments, HLA-DR antigens and immunological receptors for IgG Fc and C3b. These abnormal monocytes demonstrated impaired phagocytosis and reduced accessory cell function on PHA-mediated lymphocyte activation. Release of soluble lymphocyte-activating factors by these cells was found to be defective. Lymphocytes from the patient responded appropriately to lectin in the presence of normal monocytes. Two family members of the proband presented similar monocyte defects although they only manifested minor clinical symptoms. This syndrome underlines the interest of testing monocyte markers and function in subjects with clinical manifestations of immunodeficiency.

Adult↗