Resistance to activated protein C in adults with a history of juvenile transient ischemic attacks.
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Adult↗
Biomedical subjects
A Rocino
Publications and source records attributed to A Rocino.
Patterns of immunogenicity of an inactivated hepatitis A vaccine in anti-HIV positive and negative hemophilic patients.
Hepatitis A vaccination has been recommended to patients with hemophilia since they are exposed to potentially infectious clotting factor concentrates. Aim of this study was to assess the immunogenicity of vaccination in hemophiliacs, infected or not with the human immunodeficiency virus (HIV). A formalin-inactivated hepatitis A vaccine was injected subcutaneously to 113 susceptible adults and children and repeated after 1 and 6 months. 47 vaccinees were anti-HIV positive (28 asymptomatic, 15 with CD4 cell counts of less than 200/microliter and 4 with symptomatic disease). The first dose of vaccine induced seroconversion, with antibody titers of at least 20 mIU/ml, in 89% of the 66 anti-HIV negative patients, 100% of them responding after the second injection. In anti-HIV positive hemophiliacs seroconversion rates and antibody titers were significantly lower than in non-infected patients. After 12 months, only 76% of anti-HIV positive vaccinees and 40% of those with signs of HIV disease progression maintained the antibody, whereas all anti-HIV negative patients had titers of 20 mIU/ml or more. Our results indicate that there is an association between defective response to hepatitis A vaccine and stage of progression of HIV disease.
Adolescent↗
High titer inhibitors in severe haemophilia A. A meta-analysis based on eight long-term follow-up studies concerning inhibitors associated with crude or intermediate purity factor VIII products.
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Factor VIII↗
Incidence of factor VIII inhibitor development in hemophilia A patients treated with less pure plasma derived concentrates.
Very-high-purity Factor VIII concentrates produced by monoclonal or recombinant technology have been postulated to be more antigenic resulting in an increased risk of inhibitor development in hemophilia A patients. However, previous reports, mainly based on prevalence figures, may have underestimated the "true" risk of this complication in patients treated with less pure Factor VIII concentrates. The present study, started in 1975, has been designed to calculate the risk of inhibitor development in patients with severe or moderate hemophilia A, followed since their first exposure to intermediate or high-purity Factor VIII concentrates, produced by conventional technologies. Sixty-four hemophiliacs fulfilled the enrollment criteria. Inhibitors developed in 20.3% (13/64) of all patients and in 23% (11/48) of those with severe Factor VIII deficiency. Eleven patients manifested a strong anamnestic response after exposure to Factor VIII (high responders) and 2 had low inhibitor concentrations despite repeated Factor VIII infusions (low responders). The incidence of inhibitor development was 24.6 per 1000 patient-years of observation. The cumulative risk of inhibitor formation was 19.9% at age of 6 years, and 20.3% at 5 years after the first exposure. The risk was 19.3% at 70 days of exposure to Factor VIII concentrates, and 17.2% after a total of 50,000 units of Factor VIII given. Further studies are needed to confirm the above risk of acquiring an inhibitor, which indicates an under-estimation by previous studies. In addition, more data is needed to demonstrate whether very-high-purity Factor VIII concentrates may be more antigenic than conventional preparations.
Adolescent↗
Accelerated schedule of hepatitis B vaccination in patients with hemophilia.
Early development of immunity after hepatitis B vaccination is particularly important for patients such as hemophiliacs, at high risk for acquiring hepatitis B from potentially infectious plasma-derived concentrates. The purpose of this study was to evaluate whether or not protective antibody titers could be achieved quickly and maintained in hemophiliacs by an accelerated vaccination schedule. A yeast-recombinant hepatitis B vaccine (Engerix B, SKF Ritt) was given subcutaneously in the deltoid region and repeated 2 and 6 weeks later to 85 hemophiliacs negative for hepatitis B virus (HBV) markers. After the first 22 patients had been enrolled, a modification of the schedule involving a fourth booster dose 24 weeks after the first dose of vaccine was applied to the next 63 consecutive vaccines. Fifty-three percent of vaccinees had antibody titers to hepatitis B surface antigen (anti-HBs > or = 10 mlU/ml) by week 6, even though the mean titers of anti-HBs were somewhat lower than those achieved historically in normal individuals. The protection rate had increased to 87% by week 10, one month after the third dose of vaccine, and to 93% by week 24. One year after starting vaccination, the rate for the vaccinees who did not receive the fourth booster dose was 71%, and 96% for those who did receive the fourth dose, with only 2 patients not responding despite the booster dose. It is concluded that even though the accelerated schedule of immunization produced rapidly high rates of protective antibody titers, a booster dose is required to obtain higher titers and provide more persistent immunity.
Adolescent↗
The impact of a very high purity factor VIII concentrate on the immune system of human immunodeficiency virus-infected hemophiliacs: a randomized, prospective, two-year comparison with an intermediate purity concentrate.
Pathophysiologic considerations as well as non-comparative clinical results suggest that very high purity concentrates may slow immunologic deterioration in human immunodeficiency virus (HIV)-infected hemophiliacs. In an attempt to evaluate this hypothesis, we prospectively compared CD4 cell counts, skin testing responses, and changes of the clinical status in 20 asymptomatic HIV-positive hemophiliacs, randomly assigned to continue the treatment with an intermediate purity concentrate or to receive a very high purity product, purified by immunoaffinity chromatography with monoclonal antibodies. In the group switched to the very high purity concentrate there was no significant change of the CD4 cell counts over the 96-week follow-up period, whereas in the group continued on the intermediate purity concentrate, a highly significant decline was detected (P less than .013). Furthermore, in the very high purity group, four of six anergic patients at entry acquired reactivity to skin testing. The results of this study clearly support the use of very high purity concentrates for the replacement therapy of HIV-infected hemophiliacs.
Adult↗
AIDS and hemophilia.
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Acquired Immunodeficiency Syndrome↗
Guanylate cyclase activity in Escherichia coli mutants defective in adenylate cyclase.
Guanylate cyclase, which catalyzes the synthesis of guanosine 3',5'-monophosphate, has been assayed in several strains of Escherichia coli. They include wild-type cells and mutants defective in adenylate cyclase, which is responsible for the synthesis of adenosine 3',5'-phosphate. Our results demonstrate that adenylate cyclase and guanylate cyclase are two different enzymes in E. coli and suggest that the gene that encodes adenylate cyclase also plays a regulatory role in the synthesis of guanylate cyclase.
Adenylyl Cyclases↗
[Guanylate cyclase in Escherichia coli. I. Purification of the enzyme and evidence for an inhibitor].
Guanylate cyclase activity is present in crude E. coli extract. Guanylate cyclase has been purified 3500 fold from this extract, through ammonium sulfate fractionation, DEAE-cellulose chromatography. Sephadex G-75 gel-filtration and polyacrylamide gel preparative microelectrophoresis. During the purification a guanylate cyclase inhibitor has been separated.
Bacterial Proteins↗
[Guanyl cyclase in Escherichia coli. II. Identification and characteristics on the enzyme inhibitor].
The activity of guanylate cyclase and that of its inhibitor present in E. coli extract, have been separated through a linear KCl gradient on DEAE-cellulose column. The activity of the inhibitor is lost after ribonuclease treatment, whereas is strengthened by addition of poly (C). Other types of RNA synthetic homopolymers do not affect the inhibitor's activity. Chromatographic analysis of the products of guanylate cyclase measured in the presence of FI and FI plus poly (C), indicated that the inhibitor has a poly (C) dependent GTPase activity.
Deoxyribonucleases↗
[Guanylate cyclase in E. coli. III. Purification and possible physiological role of GTPase].
A phosphohydrolase with a preferential activity for GTP has been isolated and partially purified from E. coli extracts. The enzyme purification has been achieved through precipitation by ammonium sulfate and chromatography on DEAE-cellulose, DEAE-Sephadex, Ultragel and a second DEAE-cellulose column. The phosphohydrolase activity is poly (C) dependent. The chromatographic analysis on PEI-cellulose has shown that the main product of GTP hydrolysis is GDP. The possibility that the enzyme partially purified in this work has an important role in the control of GTP availability as substrate for guanylate cyclase into the cells has been discussed.
Chromatography, DEAE-Cellulose↗
Kaposi's sarcoma as clinical manifestation of the acquired immunodeficiency syndrome in a hemophilic patient.
The authors report the natural history of HIV infection in a patient with severe hemophilia A who became HIV-seropositive in 1983 and, four years later, developed full-blown AIDS associated with a disseminated Kaposi's sarcoma. Neutralizing antibody titers against HIV were shown to be inversely disease-associated, while the progression of clinical symptoms was directly related to the decline of T4 cells and the increase of urinary neopterin levels. It is suggested that the presence of an HLA DR 5 phenotype and repeated CMV infection could have been crucial for the development of KS.
Acquired Immunodeficiency Syndrome↗