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Biomedical subjects

J A Aznar

Publications and source records attributed to J A Aznar.

At least 37 records · Page 2Linked to original sources
PubMed2000

Influence of methylene blue photoinactivation treatment on coagulation factors from fresh frozen plasma, cryoprecipitates and cryosupernatants.

OBJECTIVE: To study the influence of virus photoinactivation with methylene blue (MB) on the coagulation factors of fresh frozen plasma (FFP) and the corresponding cryoprecipitates and cryosupernatants derived from it. MATERIALS AND METHODS: The photoinactivation procedure of the German Red Cross (Springe) was applied using Biomat (Grifols, Spain). Twenty isogroup pools of three plasma units were made from 60 U of FFP. The pools were split into three bags. One of them was photoinactivated, and pre- and postinactivation samples (MB-plasma) were obtained. The second bag was treated in the same way, followed by the preparation of MB-cryoprecipitate and MB-cryosupernatant. The third bag was not photoinactivated, and was processed in the same way to obtain control cryoprecipitate and cryosupernatant. The prothrombin time and activated partial thromboplastin time were analysed, as well as fibrinogen, factors (F) II, V, VII, VIII, IX, XI and XIII, antithrombin III, von Willebrand (vW) F:RCo, vWF:Ag and the multimeric structure of vWF. RESULTS: In plasma, the proteins most sensitive to photoinactivation were fibrinogen, FV, FVIII, FIX and FXI (24, 32, 28, 23 and 27% loss, respectively). In the MB-cryoprecipitate, the losses were higher for FVIII (23%), moderate for fibrinogen, FXIII and vWF:RCo (18, 14 and 13%, respectively) and minimal (only 3%) for vWF:Ag. In MB-cryosupernatants, the losses were higher for FV (26%) and moderate for fibrinogen (16%), FIX (18%) and FXI (19%), as well as for FII and FXIII (15%). The multimeric structure of vWF was not modified in MB-plasma or in MB-cryoprecipitates. The supernatants (both MB treated as well as controls) showed an absence of multimers of very high and high molecular weight. CONCLUSIONS: The quantitative and qualitative conservation of coagulation factors achieved in MB-plasma-derived products suggest that they are useful for the global replacement of coagulation factors and for deficiencies in FV and FXI. In countries lacking the economic resources to obtain virally inactivated concentrates, MB-cryoprecipitates could be useful in von Willebrand's disease and fibrinogen and FXIII deficiencies. MB-cryosupernatants could be employed in thrombotic thrombocytopenic purpura, in the correction of total or partial deficiencies of prothrombin complex factors and in specific deficiencies of FV and FXI.

Antiviral Agents↗
PubMed2000

Haemophilia B in a female caused by skewed inactivation of the normal X-chromosome.

Hemophilia B (factor IX deficiency) is an X-linked recessive disorder with a prevalence of 1:30,000 male births, which rarely affects females. A missense mutation T38R (6488C>G) of the factor IX (FIX) gene was characterized in a young female with moderate-to-severe hemophilia B. She is heterozygous for this mutation, which she inherited from her carrier mother. Analysis of the methyl-sensitive HpaII sites in the first exon of the human androgen-receptor locus indicated a de novo skewed X-chromosomal inactivation. This indicates that the paternal X-chromosome carrying her normal FIX gene is the inactive one, which has led to the phenotypic expression of hemophilia B in this patient.

Dosage Compensation, Genetic↗
PubMed1999

Identification of a new candidate mutation, G1629R, in a family with type 2A von Willebrand disease.

Type 2A is a qualitative variant of von Willebrand disease (vWD) characterized by a reduced platelet-dependent function, associated with an absence of large multimers. A G5135A transition, resulting in a glycine to arginine substitution at the codon 1629 of the von Willebrand factor, was identified by automated sequencing in one type 2A vWD Spanish patient. To detect this new candidate mutation a modified primer that creates a Ddel restriction site when the mutation is present was designed. This approach allowed detection of the mutation in the other three patients from the same family. On the other hand, the fact that this new mutation was not found in the 110 normal alleles screened further supports their causal relationship with the disease.

Arginine↗
PubMed1999

Postoperative use of rFVIIa by continuous infusion in a haemophilic boy.

Continuous infusion of coagulation factor concentrates has proved to be safe and effective. Because rFVIIa (NovoSeven is a very expensive product and very frequent doses are needed, continuous infusion is expected to be highly cost-effective. The postoperative use of continuous infusion of rFVIIa in a haemophilic boy with a high titre FVIII inhibitor is reported. He presented with a large right knee haemarthrosis and was treated with intermittent doses of rFVIIa. After a transient improvement the haemarthrosis became worse and an open evacuation of the joint had to be made under treatment with bolus injections of rFVIIa for 3 days (120 microg kg(-1) every 2 h). A previous pharmacokinetic evaluation in this patient had showed that FVIIa recovery and half-life were less than expected. Continuous infusion of rFVIIa (20 microg kg(-1) h(-1)), with added low molecular heparin to prevent local thrombophlebitis, was started on the fourth postoperative day and maintained unchanged for 7 days. Four additional single bolus injections were given for early joint mobilization. The intervals between replacements of the pump syringes were progressively increased from 6 to 12 h and then up to 24 h. FVIIa plasma levels during continuous infusion ranged between 6.3 and 10.4 IU mL(-1). Although +FVIIa assays seemed to show good stability, we observed the formation of precipitates inside the syringes. The precipitates seemed to contain FVIIa. We concluded that FVIIa+ plasma levels of 6-10 IU mL(-1) were safe and effective to prevent postoperative haemorrhage in this patient. The addition of heparin to the rFVIIa concentrates, however, may cause precipitation and should be avoided. Individual pharmacokinetic evaluation may be useful to select the appropriate initial doses, especially in young patients.

Adolescent↗
PubMed1999

Factor VIII/von Willebrand factor complex in methylene blue-treated fresh plasma.

BACKGROUND: The effect of virus inactivation of fresh plasma with methylene blue has been studied on the factor VIII/von Willebrand factor molecular complex (FVIII/vWF), factor XIII, and fibrinogen. STUDY DESIGN AND METHODS: FVIII function or activity, vWF activity, vWF antigen, vWF:Ag, vWF multimeric structure, fibrinogen, and factor XIII were analyzed in paired samples of control fresh plasma (untreated) and the same fresh plasma treated with methylene blue. Treated plasma was filtered (0.8-1.2 microm), mixed with a methylene blue solution (300 microg/L), and illuminated at 50,000 lux for 30 minutes on both sides. RESULTS: Average loss of biologic activity of coagulation factors studied was 25 percent (FVIII function, 29%; fibrinogen, 39%; factor XIII, 16%; and vWF activity, 18%). Reduction in vWF activity was significantly lower than that in FVIII function (p<0.05), and the vWF multimeric structure did not show alterations. CONCLUSION: Methylene blue-treated plasma and the cryoprecipitates obtained from it may be effective for replacement therapy in cases of von Willebrand disease and deficiencies of factor XIII and fibrinogen, but the clinical studies are needed to verify that possibility.

Dimerization↗
PubMed1998

Search for mutations in a segment of the exon 28 of the human von Willebrand factor gene: new mutations, R1315C and R1341W, associated with type 2M and 2B variants.

von Willebrand Disease (vWD) is the most frequently inherited bleeding disorder in humans, and is caused by a qualitative and/or quantitative abnormality of the von Willebrand factor (vWF). A large number of defects that cause qualitative variants have been located in the A1 domain of the vWF, which contains sites for interaction with platelet glycoprotein Ib (GPIb). We have developed a new approach to detect mutations based on DdeI digestion and single-strand conformation polymorphism analysis. A segment of 487 nucleotides, extending from intron 27 to codon 1368 of the pre-pro vWF was amplified from genomic DNA. The cleavage with DdeI yields two fragments of appropriate size for this kind of analysis and confirms that the gene, rather than the pseudogene, is being investigated. Six families with type 2B vWD, one type 2M vWD family, and one another type 2A vWD family were studied. After sequencing the fragments with an altered electrophoretic pattern, we found four mutations previously described--R1308C, V1316M, P1337L, and R1306W--in patients with 2B vWD. The last one arose de novo in the patient. In addition, two new candidate mutations were observed: R1315C and R1341W. The first one was associated to type 2M vWD, whereas the one second cosegregated with type 2B vWD. The fact that these new mutations were not found in 100 normal alleles screened further supports their causal relationship with the disease. These mutations, which induce either a gain or a loss of function, further show an important regulatory role of this region in the binding of vWF to GPIb and its implications in causing disease.

Amino Acid Substitution↗
PubMed1998

Zero incidence of inhibitor development in previously treated haemophilia A, HIV-negative patients upon exposure to a plasma-derived high-purity and double viral inactivated factor VIII concentrate.

Thirty-six haemophilia A, HIV-negative, previously treated patients were changed therapy to a highpurity and double-inactivated (solvent/detergent and dry-heating) previously unused factor VIII concentrate. The mean age of these patients was 27 years at the time of the change. Twenty-three patients were severe haemophiliacs (FVIII:C < 0.02 IU mL-1), seven moderate (FVIII:C between 0.02 and 0.05 IU mL-1) and six mild (FVIII:C > 0.05 IU mL-1). The mean follow-up with this single product was 16 months, with 82 accumulated exposure days and the mean consumption was 117,300 IU of FVIII corresponding to a mean of six batches per patient. No patient developed FVIII inhibitors (upper limit of the CI95: 7.98%), resulting in an incidence rate of 0/48 patient-years (upper limit of the CI95: 77/1000 patient-years). The change in therapy to this new factor VIII concentrate was not associated with the appearance of inhibitors.

Adolescent↗
PubMed1998

Development of a factor VIII inhibitor in a newborn haemophiliac.

A major problem in the treatment of haemophilia A is the development of inhibitors (antibodies) against factor VIII. We report the case of a newborn male with no family history of haemophilia who developed an intracerebral haemorrhage. On day 10 post-delivery severe haemophilia A was diagnosed and treatment with recombinant FVIII (rFVIII) concentrate was started. Seventy-two hours later the presence of inhibitors was suspected because high doses of rFVIII were required to maintain therapeutic FVIII plasma levels. Days after, the inhibitor was detected. The quick detection of the inhibitor in this newborn haemophiliac allowed us to start the immunotolerance early, without interruption in the administration of rFVIII.

Autoantibodies↗
PubMed1996

[Seroprevalence of hepatitis A in hemophiliacs].

PURPOSE: To study the seroprevalence of hepatitis A virus (HAV) infection in haemophiliacs treated with factor VIII/IX concentrates. PATIENTS AND METHODS: Anti-HAV IgG antibodies were tested in 133 haemophiliacs previously treated (20 of them only infused with virus-inactivated factor concentrates), 11 previously untreated haemophiliacs and 60 healthy individuals (> 25 yr. old). RESULTS: The overall anti-HAV prevalence was 43%. Anti-HAV was found in 2 (10%) of the patients treated only with virus-inactivated concentrates and in 55 (49%) of those who had received non-inactivated concentrates. The seroprevalence in the untreated haemophiliacs was 27% and 90% in the healthy control group. The anti-HAV seroprevalence showed a significant (p < 0.001) dependence on patient age, it being higher in patients aged > 25 (77%) than in those aged 10-25 (31%) and < 10 (4%). The seroprevalence of anti-HAV was lower in the treated haemophiliacs aged 25 or more than in the healthy individuals, although the difference did not reach statistical significance (p = 0.06). CONCLUSION: These results show that the seroprevalence of HAV infection in haemophiliacs is similar to that in the general population, and that there is not a significant excess of HAV infections amongst haemophiliacs with high exposure to coagulation factor concentrates.

Adolescent↗
PubMed1995

[Is it possible to improve psychiatric care through the referral process?].

OBJECTIVE: To evaluate the quality of referral from Primary Care to Mental Health and its relationship to the illness referred. DESIGN: A descriptive retrospective study over 4 years on the quality of the process. SETTING: Mental Health Centre II in the Autonomous Community of Murcia. PATIENTS: 209 patients referred by three Primary Care teams. MEASUREMENTS AND MAIN RESULTS: 91.4% of patients (C.I. 95%: 100%, 81.1%) were accepted with a referral report. 97.9% (C.I. 95%: 100%, 87.8%) presented a reason for psychiatric consultation. The report included the clinical history of the illness in 58.1% of cases (C.I. 95%: 70.3%, 45.9%); a diagnostic opinion was given in 79.6% (C.I. 95%: 91.1%, 68%); and 37.2% (C.I. 95%: 49.3%, 25%) were referred with a request for a specific consultation. 68.4% of the referrals (C.I. 95%: 81.8%, 54.9%) coincided with the Mental Health diagnosis. It was observed that among the most commonly referred pathologies: anxiety disorders (31.6%), affective (28.8%), personality (7.7%), psychotic (5.3%), and adaptive disorders (5.3%); diagnoses were commonly made for affective or anxiety disorders (p < 0.0001); the specific cause of referral of anxiety disorders was recorded (p < 0.01); and in cases of psychotic and personality disorders, the diagnoses did not coincide (p < 0.001). CONCLUSIONS: Referral to Mental Health can be improved, fundamentally by sending a report which includes the clinical history and the reason for referral. It is common to express a diagnostic opinion on affective and anxiety disorders, to note a specific reason for referral in the case of anxiety disorders and not to specify personality and psychotic disorders.

Humans↗
PubMed1993

[Evolution of CD4 and CD8 lymphocyte subsets in HIV seronegative and seropositive hemophiliacs].

PURPOSE: To asses the evolution over time of the CD4, CD8 and total lymphocyte counts in both HIV seronegative and HIV seropositive haemophiliacs. PATIENTS AND METHODS: A total of 124 haemophilic patients (77 HIV seropositive and 47 HIV seronegative) regularly controlled at our Hospital were studied. All patients have had several (range 2-15) CD4 and CD8 lymphocyte counts, with a minimum interval of 2 or more years between the first count and the last one (median 7.7 years). A linear regression analysis of the serial cell counts against the time was made and the corresponding slopes were estimated for each patient and expressed as a percentage of the initial values (standardized slopes). RESULTS: In HIV seronegative patients the number of CD4, CD8 and total lymphocytes decreased (p < 0.05), but the decrease of the CD4/CD8 ratio was not statistically significant. The decline of the CD4 cells showed a trend to remain above 500 cells/microL. HIV seropositive hemophiliacs had also a substantial decline of lymphocyte counts (p < 0.0001), but essentially due to changes of the CD4 cells, which declined with a nearly constant rate during the follow-up (median values decreased from 793/microL to 324/microL). CD8 cell counts diminished in lower grade than the CD4 cells counts, and consequently the percentage of the total lymphocyte number increased from 42% to 55%. The CD4/CD8 ratio decreased with a standardized slope of -5.7% per year. At the initial evaluation the seropositive patients had CD4 cell counts and CD4/CD8 ratios lower than seronegative ones, but CD8 cell counts were higher in the first group. Total lymphocyte counts were not statistically different at this first evaluation between infected and non-infected patients. At the final evaluation, differences on CD4 cell counts and CD4/CD8 ratio increased, and lymphocyte counts were significantly lower in the HIV-seropositive haemophiliacs. However, the final absolute counts of CD8 cells were not dissimilar in the two groups of patients. The median standardized slopes of the total lymphocyte counts, CD4 cell counts, and CD4/CD8 ratios were significantly more negative for the HIV-infected patients (-5.7%, -9.4 and -5.7%, respectively) than were these for the non-infected ones (-2.0%, -3.2% and -2.5%, respectively). CONCLUSIONS: Lymphocyte counts, mainly the CD4 cell counts, decline in treated haemophiliacs independently of their HIV status. In the HIV seronegative patients the CD4 cell counts generally stabilize above 500 cells/microL. However, in the seropositive haemophiliacs these counts show a continuous fall, with a median rate of 9% of the initial value per year.

Adolescent↗
PubMed1992

[Progression to AIDS among HIV-seropositive hemophiliacs].

PURPOSE: To assess the incidence of AIDS, along with its origin and mortality rate, in a group of sero-positive haemophiliacs with long follow-up. MATERIAL AND METHODS: The progression into AIDS in 94 HIV-seropositive haemophiliacs (88 with haemophilia A and 6 with haemophilia B) followed since 1986 has been analyzed. The mean age was 19 years and 64% of the patients had severe haemophilia. All of them had been previously treated with non virus-inactivated factor concentrates. Was detected HIV antigen in 13 of them and 32 were treated with zidovudine. Actuarial analysis started from seroconversion date or from the first positive result and the average observation time was 90 months (5-97). RESULTS: Sixteen patients developed AIDS, resulting in an eight-years accumulative actuarial indice of about 24%. AIDS incidence was lower (p less than 0.0001) in haemophilia A (21%) than in haemophilia B (67%). The eight-years progression rate to AIDS showed a significant dependence on patient age, it being higher in patients aged greater than 30 (77%) than in those aged 15-30 (30%) and less than 15 (9%). Patients who presented CD4+ counts lower than 0.5 x 10(9)/L or CD4/CD8 ratios lower than 0.5 at the beginning of the observation period had a greater 8-year AIDS incidence (63% and 57% respectively) than the remaining patients (16% and 12%). At AIDS diagnosis, all patients had CD4+ lymphocyte counts lower than 0.2 x 10(9)/L, two had detectable HIV antigenaemia and six had been previously treated with zidovudine. The cause of AIDS was an opportunistic infection in all the cases namely, P. carinii pneumonia and candidiasis, but no secondary neoplasia was registered. Nineteen patients died during the follow-up, 12 because of AIDS and 7 because of other reasons unrelated to HIV-infection. CONCLUSION: Our results suggest that 25% of the haemophiliacs will develop AIDS eight years after seroconversion, and a decreasing incidence is not observed. Lower progression rate to AIDS in children than in adults is confirmed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Detection of two different anti-factor VIII/von Willebrand factor antibodies of the IgA class in a hemophilic patient with a polyclonal factor VIII inhibitor of the IgG class.

A hemophilic patient treated with Factor VIII (F.VIII) concentrates developed a F.VIII inhibitory activity. The patient's plasma showed 2 anti-F.VIII/von Willebrand Factor (vWF) antibodies (Abs) of the IgG and IgA class respectively. The specific anti-F.VIII/vWF Abs were isolated and resulted to be IgG (20 micrograms/ml) and IgA (35 micrograms/ml). The plasma was subsequently fractionated by Protein A-Sepharose and the IgG and IgA containing fractions were separately analyzed for anti-F.VIII activity. Both fractions exhibited F.VIII inhibitory activity, but that corresponding to the IgA was lower than expected. Regarding the possible existence of a non-inhibitor Ab in the IgA containing sample, plasma was processed through an immunoadsorbent to which a F.VIII devoid vWF preparation had been previously coupled and further fractionated by Protein A-Sepharose, obtaining 2 IgA fractions. One of them exhibited F.VIII inhibitory activity while the other, which reacted with the F.VIII devoid vWF preparation, did not. Therefore, this latter one was considered as a true anti-vWF Ab. The IgG and IgA inhibitors were polyclonal and the IgG one was composed of the 4 IgG subclasses.

Adult↗
PubMed1991

[Human immunodeficiency virus infection in hemophiliacs: prevalence and current clinical situation].

The prevalence of HIV-antibody was studied in a cohort of 156 haemophiliacs controlled since before 1986. Ninety four patients (60%) were HIV-seropositive, and all of them had been previously treated with non-heated factor concentrates. Seroprevalence was 50% by 1983. Evidence for previous negative results was only available in 19 seropositive patients and all of them seroconverted before 1985. For the 148 patients exposed to non-heat treated factor concentrates, severe haemophiliacs and those with factor consumption greater than 100 x 10(3) had the maximal rate of seropositivity (81% and 75% respectively, p less than 0.005). Fifteen patients developed AIDS (10% of the HIV-positive), 12 of which have died. HIV infection has a high prevalence and it has become the most important cause of death in our haemophiliacs.

Adolescent↗
PubMed1990

Immunological characterization of factor VIII inhibitors by a sensitive micro-ELISA method.

A micro-ELISA method for the immunological characterization of factor VIII (F. VIII) inhibitors is described. Microplates sensitized with purified monospecific anti-von Willebrand factor (vWF) IgG were firstly incubated with a commercial F. VIII concentrate and then with the samples containing the F. VIII inhibitors to be characterized. Peroxidase conjugated monospecific antisera were used to determine the Ig class and the light chain type. Alkaline phosphatase conjugated monoclonal antibodies were employed to investigate the IgG subclasses. The F. VIII inhibitors from 8 hemophiliacs and 1 patient with systemic lupus erythematosus (SLE) were characterized. All of them belonged to the IgG class but one case simultaneously exhibited another inhibitor of the IgA class. Eight inhibitors analyzed for light chains resulted to be polyclonal. In 7 cases the inhibitors belonged solely to the IgG4 subclass while in the other 2 cases contained all the 4 IgG subclasses. The method appears to be simple, accurate and highly sensitive (detecting as low as 0.156 Bethesda Units/ml) for the immunological characterization of F. VIII inhibitors.

Autoantibodies↗
PubMed1989

[ELISA method for the determination of factor VII antigen].

The low plasma concentration of clotting factor VII makes it difficult to assay its antigenic fraction by the conventional methods of precipitation with specific antigens. Simple and peroxidase-conjugated antisera are currently available from commercial sources, thus allowing one to determine F VII:Ag by enzyme immunoassay. An ELISA method has been developed in this laboratory which provides sensitivity limits about 0.1% of the plasma concentration of F VII and correlates significantly with its functional activity (r = 0.603, n = 44, p less than 0.001). This technique can be highly helpful in characterising molecular variants of F VII, as well as in detecting acquired deficiencies of this factor.

Antigens↗