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J Oldenburg

Publications and source records attributed to J Oldenburg.

At least 73 records · Page 4Linked to original sources
PubMed1997

Severe bleeding in two patients due to increased sensitivity of factor IX activity to phenprocoumon therapy.

Two male patients with severe and recurrent bleeding episodes under phenprocoumon therapy are reported. Both patients exhibited a strong decrease of their factor IX activities below 1% of normal, whereas the activities of the vitamin K-dependent factors prothrombin, VII, and X were found to be within or above the expected therapeutic ranges of 20-40%. Upon removal of phenprocoumon and substitution with vitamin K, the factor IX activities increased to 85% and 55%, respectively. Reexposition to phenprocoumon in one patient confirmed the rapid and selective decrease of the factor IX activity. These findings provide the first report of an abnormally high sensitivity of factor IX activity to oral anticoagulant therapy.

Adult↗
PubMed1997

Factor VIII gene mutations found by a comparative study of SSCP, DGGE and CMC and their analysis on a molecular model of factor VIII protein.

Screening of the factor VIII (FVIII) gene which spans 186 kb and codes for 26 exons, was originally hampered by its size but is now feasible because rapid DNA scanning methodologies have been developed. The present study for the first time directly compares the three most widely applied screening methods, denaturing gradient gel electrophoresis (DGGE), single-stranded conformational polymorphism (SSCP) and chemical mismatch cleavage (CMC) for their sensitivity of mutation detection in a selected group of ten haemophilia A patients. Nine of these patients are known to be cross-reacting material positive and eight exhibited a mild to moderate phenotype. Of the ten patients screened, we identified mutations in nine by all three screening methods. Of the mutations characterised, two are previously unpublished. T to C (S373P) and G to A (D525N). In one mildly affected haemophiliac, we identified a second T to C sequence change in the 5' untranslated region at -601 bp, probably having no effect on FVIII gene expression. Modelling studies were performed on those mutations lying within the A domains of FVIII (D525N, R527W, I566T) to study the possible effect of these mutations on structure and/or function. When the three methods are performing optimally and have been standardised, our experience is that CMC and DGGE are equally efficient at sequence variation detection while SSCP is slightly less sensitive.

Computer Simulation↗
PubMed1997

Missense mutations at ALA-10 in the factor IX propeptide: an insignificant variant in normal life but a decisive cause of bleeding during oral anticoagulant therapy.

Bleeding complications are the most common and unwanted side-effect of oral anticoagulant therapy. We report three patients in whom mutations in the factor IX (FIX) propeptide were found to cause severe bleeding during coumarin therapy. Strikingly, the bleeding occurred within the therapeutic ranges of the prothrombin time (PT) and international normalized ratio (INR). In all three patients coumarin therapy caused an unusually selective decrease of FIX activity (FIX:C) to levels below 1-3%. Upon withdrawal of coumarin, FIX:C increased to subnormal or normal values of 55%, 85% and 125%, respectively. Analysis of the FIX gene revealed two different missense mutations affecting the Ala-10 residue in the propeptide coding region: Ala[GCC] to Val[GTC] in two patients and Ala[GCC] to Thr[ACC] in one patient. No further mutation was detected by screening 195 random blood donors for mutations at Ala-10, thus excluding a frequent polymorphism at this position. The mutation in the FIX propeptide at a position which is essential for the carboxylase recognition site causes a reduced affinity of the carboxylase enzyme to the propeptide. This effect leads to an impaired carboxylase epoxidase reaction which is decisively triggered by the vitamin K concentration. Determination of FIX and APTT in addition to PT and INR is therefore recommended in coumarin-treated patients with an uncommon bleeding pattern.

Administration, Oral↗
PubMed1997

HLA genotype of patients with severe haemophilia A due to intron 22 inversion with and without inhibitors of factor VIII.

Molecular genetic studies have shown that development of antibodies to factor VIII (inhibitors) occurs most frequently in patients with severe haemophilia due to major gene lesions including inversions, stop codons and large deletions. Previous studies of HLA type were performed on inhibitor and non-inhibitor patients with diverse uncharacterized mutations which may have confounded detection of significant associations. We therefore selected a group of patients with a single mutation type, the prevalent intron 22 inversion, with or without inhibitors, to determine HLA genotype. Seventy-one such patients, 42 without and 29 with inhibitors (13 high, 9 low and 7 transient responders) were genotyped for MHC Class I HLA-A, -B, -C and Class II HLA-DQA, -DQB and -DRB loci. No strong correlation of any HLA-allele to inhibitor or non-inhibitor status was found. However, alleles of the haplotype HLA-A3, HLA-B7, HLA-C7, HLA-DQA0102, HLA-DQB0602, HLA-DR15 occurred more often in inhibitor patients. Since the alleles of this extended haplotype are common in the North European population only a very strong association would achieve statistical significance. Further studies of groups of patients similar to those studied here will be needed to confirm or exclude this association.

Alleles↗
PubMed1996

The prevalence of antibody to parvovirus B19 in hemophiliacs and in the general population.

The prevalence of antibodies to parvovirus B19 (B19) was measured in the sera of 566 hemophiliacs and 524 individuals of the general population by immunofluorescence assays, using antigen expressed by the baculovirus system. In the general population, anti-B19 IgG seroprevalence was found to continuously decline from 64 percent at birth to 0 percent in the age of 9-11 months and thereupon to increase to 61 percent in the age of 12 years. In younger adults and older people, IgG seroprevalence only slowly increased with age, reaching 77 percent in people aged 60 and above. In contrast, in hemophilic children treated exclusively with virally inactivated clotting factor concentrates, neither decrease nor increase of B19 IgG antibody was detectable and the overall seroprevalence was 92 percent. In the group of hemophiliacs older than 12 years and treated before 1984 with non-inactivated clotting factor concentrates, 98 percent showed antibody to B19. Anti-B19 IgM seroprevalence was significantly higher in hemophilic than in non-hemophilic individuals older than 12 years. Since it seems to be unlikely that the high seroprevalence in hemophiliacs is acquired by immunization with inactivated viral antigen, the results suggest that infection with B19 is transmitted by clotting factor concentrates, even if subjected to virucidal methods.

Adolescent↗
PubMed1996

Characterization of the factor VIII defect in 147 patients with sporadic hemophilia A: family studies indicate a mutation type-dependent sex ratio of mutation frequencies.

The clinical manifestation of hemophilia A is caused by a wide range of different mutations. In this study the factor VIII genes of 147 severe hemophilia A patients--all exclusively from sporadic families--were screened for mutations by use of the complete panel of modern DNA techniques. The pathogenous defect could be characterized in 126 patients (85.7 percent). Fifty-five patients (37.4 percent) showed a F8A-gene inversion, 47 (32.0 percent) a point mutation, 14 (9.5 percent) a small deletion, 8 (5.4 percent) a large deletion, and 2 (1.4 percent) a small insertion. Further, four (2.7 percent) mutations were localized but could not be sequenced yet. No mutation could be identified in 17 patients (11.6 percent). Sixteen (10.9 percent) of the identified mutations occurred in the B domain. Four of these were located in an adenosine nucleotide stretch at codon 1192, indicating a mutation hotspot. Somatic mosaicisms were detected in 3 (3.9 percent) of 76 patients, mothers, comprising 3 of 16 de novo mutations in the patients mothers. Investigation of family relatives allowed detection of a de novo mutation in 16 of 76 two-generation and 28 of 34 three-generation families. On the basis of these data, the male:female ratio of mutation frequencies (k) was estimated as k = 3.6. By use of the quotients of mutation origin in maternal grandfather to patients mother or to maternal grandmother, k was directly estimated as k = 15 and k = 7.5, respectively. Considering each mutation type separately, we revealed a mutation type-specific sex ratio of mutation frequencies. Point mutations showed a 5-to-10-fold-higher and inversions a >10-fold-higher mutation rate in male germ cells, whereas deletions showed a >5-fold-higher mutation rate in female germ cells. Consequently, and in accordance with the data of other diseases like Duchenne muscular dystrophy, our results indicate that at least for X-chromosomal disorders the male:female mutation rate of a disease is determined by its proportion of the different mutation types.

Base Sequence↗
PubMed1996

Results of a screening for von Willebrand disease type 2N in patients with suspected haemophilia A or von Willebrand disease type 1.

A screening program for the detection of patients with von Willebrand disease type 2N (VWD 2N) was carried out in 177 unrelated patients previously diagnosed with haemophilia A and in 199 unrelated patients with VWD type 1 in comparison. By measuring the factor VIII (FVIII) binding capacity of von Willebrand factor (VWF), we detected 13 patients with VWD 2N within 8 unrelated families. The former diagnosis has been haemophilia A in 5 index patients, and VWD in the remaining 3. Included in this study were 14 patients with suspected haemophilia A, whose molecular analysis for mutations in the FVIII gene was unsuccessful. Five of them had VWD 2N. In all patients with the VWD 2N phenotype we were able to identify specific molecular defects in the corresponding DNA sequence of the FVIII binding domain of VWF. The most common defect was R91Q. Four patients from 4 families were homozygous for R91Q, six patients from 3 families were compound heterozygous for R91Q and a silent yet unidentified allele. The VWD 2N phenotype of father, daughter, and son in one family, was based on 2 different genotypes, compound heterozygosity for R91Q and VWD type 1 in the father and the daughter, and homozygosity for R91Q in the son. Two patients from one family were compound heterozygous for T28M and delta C2680-2685 in exon 18, and one patient was compound heterozygous for a novel candidate missense mutation in exon 18(E24K) and delta C2680-2685 in exon 18 which is regarded the most common defect causing severe VWD type 3. FVIII:C values of 0.07 and 0.14 IU/ml were observed in patients with the genotype T28M/delta C2680-2685 whereas in patients being homozygous or compound heterozygous for R91Q, FVIII:C was 0.19 +/- 0.071 IU/ml. In contrast to the other genotypes, E24K/delta C2680-2685 is correlated with a more severe haemophilic phenotype with a FVIII residual activity of only 0.01-0.02 IU/ml. This emphasizes the need for inclusion of the factor VIII binding assay in the diagnostic workup of suspected haemophilia A.

Adult↗
PubMed1996

Immunosuppression may lead to progression of hepatitis C virus-associated liver disease in hemophiliacs coinfected with HIV.

OBJECTIVE: The aim of this study was to examine the interaction between HIV and hepatitis C virus (HCV) in hemophiliacs coinfected with the viruses and to investigate the possible relationship between immunosuppression and liver failure. METHODS: To identify risk factors for impending liver failure in hemophiliacs coinfected with HIV and HCV, we analyzed clinical and laboratory parameters, including CD4 count, aminotransferases (ALT, AST), cholinesterase, alkaline phosphatase, bilirubin, and gamma-glutamyltransferase, during 3 yr of follow-up (1990-1993) in four groups of patients: hemophiliacs with progressive immunodeficiency who were coinfected with HCV and HIV (group A, n = 49); hemophiliacs with stable immune function who were seropositive for HIV and HCV (group B, n = 95); hemophiliacs who were infected with HCV but not HIV (group C, n = 72); and homosexuals with progressive immunodeficiency who were infected with HIV but not HCV (group D, n = 24). RESULTS: Univariate analysis of data for group A showed a significant rise in gamma-glutamyltransferase and alkaline phosphatase (p < 0.01) that was not seen in groups B, C, and D. In a multivariate Cox regression analysis, age (odds ratio, 1.054 per yr; 95% confidence interval, 1.014-1.096 per yr), decline in CD4 count (odds ratio, 1.063 per cell/microl; 95% confidence interval, 1.037-1.091 per cell/microl), and alkaline phosphatase level (odds ratio, 1.012 per U/L; 95% confidence interval, 1.002-1.021 per U/L) emerged as independent determinants of death. CONCLUSIONS: Our data suggest that progressive immune dysfunction in hemophiliacs coinfected with HIV and HCV may influence progression of liver failure. In these patients cholestasis is an additional prognostic marker for survival that may reflect both exhausted immunity and impaired liver function.

Acquired Immunodeficiency Syndrome↗
PubMed1995

The genetic diversification of the HIV type 1 gag p17 gene in patients infected from a common source.

An evolutionary analysis was undertaken of HIV-1 gag p17 sequences taken from a small cohort of hemophilia B patients infected from a common batch of clotting factor concentrate. The sequence population found at seroconversion was highly homogeneous, suggesting that the infecting batch also contained little sequence variation. Genetic diversification was found in follow-up sequences taken approximately 3 years later and was generally found to be complex. Greater rates of synonymous to nonsynonymous substitution were observed, especially when comparing distantly related isolates, and the rate of synonymous substitution was used to estimate times of divergence for a number of isolates of HIV-1 including the origin of the subtypes A to H. The p17 region is therefore proposed as a useful marker for future epidemiological studies.

Amino Acid Sequence↗
PubMed1995

Characterization of mutations within the factor VIII gene of 73 unrelated mild and moderate haemophiliacs.

To screen for mutations within the factor VIII gene of 101 patients (85 unrelated), we used denaturing gradient gel electrophoresis (DGGE) after DNA amplification of target regions, including all coding regions except for the middle part (amino acid 757 to amino acid 1649) of the B domain. With this method, missense mutations were identified in 86% of unrelated patients. 41 different mutations were identified: 25 of them have not been described previously. Five of the genotypes are associated with CRM+ and 26 with CRMred status. Patients who are definitely related to each other showed no differences in DNA sequence. One patient showed two different base pair alterations, the first at amino acid 469 [ala(GCA-->gly(GGA)] and the second at position 473 [tyr(TAT)-->cys(TGT)]. One patient with an amino acid change at position 1689 [arg(CGC)-->his(CAC)] has developed an inhibitor against factor VIII.

Base Sequence↗
PubMed1995

Haemophilia A: mutation type determines risk of inhibitor formation.

The formation of factor VIII antibodies is a major problem for replacement therapy of haemophilia A patients. Antibodies occur in 5-30% of patients with severe haemophilia A. The reason for antibody formation is still unknown. In this study we correlate for the first time different factor VIII gene mutations, stop- and missense mutations, large and small deletions and intrachromosomal intron 22 recombinations to antibody formation. A total of 364 patients with known inhibitor status of our institute, of the database, and of 3 studies representing intron-22-inversion data are included. The results show that the risk for developing factor VIII antibodies is strongly related to stop mutations. large deletions and intrachromosomal recombinations. A probable explanation could be the complete lack of endogenous circulating factor VIII protein in these cases. Other factors that might be important for the pathogenesis of inhibitor formation, e. g. the antenatal period, as well as possible therapeutic effects, are discussed.

Antibodies↗
PubMed1994

Characterization of resistance mechanisms to cis-diamminedichloroplatinum(II) in three sublines of the CC531 colon adenocarcinoma cell line in vitro.

Cisplatin resistance was developed in sublines of the CC531 rat colon adenocarcinoma cell line by continued low level drug exposure. Two relatively stable lines were obtained (RL2 and RL4) which were 6- and 20-fold more resistant to cisplatin. In addition, a subline more sensitive than the parent line by a factor of 2 (RLS) was obtained by subculture from a treated tumor. Mechanisms of resistance to cisplatin were investigated in these four lines, with the aim of determining the relative contributions of different resistance mechanisms at various resistance levels. Drug accumulation linearly decreased with increasing drug resistance. A 20-fold resistance was associated with only a 5-fold decrease in accumulation, suggesting that other resistance mechanisms may be involved in the total degree of resistance. Intracellular glutathione, measured fluorometrically, also increased with increasing resistance, varying by a factor of 4 between the most and least resistant lines. Reduction of glutathione levels by buthionine sulfoximine to parent line levels increased sensitivity but the cells remained considerably more resistant than parent cells. Resistant lines cultured in the absence of drug became progressively more sensitive, without accompanying changes in total glutathione levels. DNA-drug adducts, the presumed toxic lesion, were measured immunocytochemically. Initial levels decreased with increasing platinum resistance, although not proportional to resistance (factor of 5 decrease for 20-fold resistance). Drug dose ratios for equal initial adducts were similar to dose ratios for equal drug accumulation, implying that intracellular concentrations solely determine DNA adduction and that differences in glutathione level had little influence on the proportion of drug which eventually formed adducts. After 48 h, a better correlation between remaining adducts and resistance was found (factor 12 less adducts for 20-fold resistance). This implies that repair of adducts was important in determining survival. These data indicate that decreased drug accumulation played a proportionally greater role in the moderately resistant cell line and that adduct repair played a progressively greater role in the highly resistant cell line.

Adenocarcinoma↗
PubMed1994

[HIV-associated parotid cysts].

20 seropositive HIV patients were examined for the detection of parotid cysts by means of B-mode sonography. In three cases bilateral cysts were found, in three cases unilateral. Only one patient showed clinical symptoms with a bilateral and painless parotideal mass. The cysts were 0.32 to 3.8 cm in diameter. No correlation could be found, neither to the CDC-classification (according to the Center for Disease Control) nor to different HIV-related lesions. Pathogenesis, diagnostic procedure, and clinical relevance of this new entity are discussed. HIV-seropositive patients should be examined sonographically for detection of parotid cysts as indicators for early manifestation of a HIV infection. It is recommended that in patients having cervical sonography for any reasons, a hidden HIV-infection should be excluded once cystic parotideal lesions have been detected.

Adult↗
PubMed1994

[Hemophiliac arthropathy of the knee joint. Gd-DTPA-enhanced MRI; clinical and roentgenological correlation].

17 patients with hemophilic arthropathy of the knee joint were studied with static and dynamic MRT before and after i.v. bolus injection of Gadolinium-DTPA (0.1 mmol/kg body weight). After contrast enhancement, synovial proliferations exhibited an increase of signal intensity (SI) on FFE and SE images of 47.7% and 37.4% respectively, whereas muscle and fatty tissue, tendons, bone marrow and joint effusion revealed only minor increase in SI. The gradient of signal intensity (ratio SI/time) of pannus was 39.6%/min. Gd-DTPA enhanced MRI studies delineate and quantify the synovial proliferations in hemophilic arthropathy. Dynamic studies in hemophilic arthropathy do not provide qualitative assessment of the inflammatory process.

Adult↗