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Biomedical subjects

A Braun

Publications and source records attributed to A Braun.

At least 127 records · Page 7Linked to original sources
PubMed1996

Population study of the G1691A mutation (R506Q, FV Leiden) in the human factor V gene that is associated with resistance to activated protein C.

The mutation G1691A (R506Q) in the human factor V gene is associated with the resistance to activated protein C (APC) that represents a major risk of development of venous thrombosis. A population study of 180 unrelated individuals from south Germany was performed. Examination of the allelic frequencies revealed a high prevalence of this disease-related mutation (Q506, FV Leiden). The heterozygosity rate was 7.8% with a confidence interval between 4% and 11%.

Base Sequence↗
PubMed1996

A novel sequence polymorphism in the promoter region of the human B2-bradykinin receptor gene.

The distribution of a nucleotide polymorphism in the core promoter of the human B2-bradykinin receptor gene was examined in the population of southern Germany. The allelic frequencies were 0.595 for C allele and 0.405 for the T allele. The allele frequencies were in Hardy-Weinberg equilibrium. This new marker provides a valuable tool to assess the risk for putative bradykinin-associated disorders with genetic determinism.

Alleles↗
PubMed1996

Polymorphisms in the gene for the human B2-bradykinin receptor. New tools in assessing a genetic risk for bradykinin-associated diseases.

The B2-bradykinin receptor gene has been proposed as one of the candidate genes involved in the complex genetic underpinnings of common chronic disorders such as hypertension, ischemic heart disease or allergic asthma. Suitable genetic markers are needed to study these hypotheses. Therefore, it was our aim to identify polymorphic sites in the B2-receptor gene. Up to now, we characterized four polymorphisms: one in the promoter region and three other ones in each of the exons. Possible biological consequences are delineated and preliminary results of allele specific different biological action are shown.

Alleles↗
PubMed1996

Special considerations concerning regulatory requirements and drug development for peptides and biotech products in the EU.

The marketing authorization for a new medicinal product is based on the scientific assessment of its quality, safety and efficacy. The marketing authorization application (MAA) which covers all the relevant documentation can be filed in the EU via different application procedures. For peptides and biological products special issues have to be taken into consideration during drug development. Due to special production procedures and the complexity of the active substance itself, peptides and biotech products are subject to specific regulatory requirements. This leads to the necessity to discuss the development program of a new peptide or biotech product with the health authorities on a case by case basis. This article will focus on the special regulatory requirements for peptides and biotech products including the registration procedures as well as technical, preclinical and clinical issues.

Biotechnology↗
PubMed1996

Localized amyloid in the menisci of the knee joint.

This is, to the best of our knowledge, the first report on amyloid deposits in menisci. Fragments of menisci gained by arthroscopy from 316 patients between 20 and 80 years of age were examined. Amyloid was found in 70% of the cases from male, as well as female patients. The amyloid amount found was always very small, but the deposits seemed to increase with age. Patients more than 50 years of age all had menisceal amyloid. Two types of deposits were observed: a)stroma-deposits in the deep central portions of the menisci (tiny dots of intensely stained amyloid and/or ill defined patches of low staining intensity) and b) surface associated deposits: band-like amyloid imbibition of the collagenous stroma immediately beneath the surface of the menisci but not deeper than 0.2 mm. In all cases, amyloid was resistant when pretreated by KMn04 and immunohistologically antisera against amyloid types AA, AB and AF were negative. 3/25 cases showed a reaction with an amyloid-lambda-antibody. We assume, that amyloid in menisci is a further type of localized senile amyloidosis.

Adult↗
PubMed1996

Expression and cellular localization of kininogens in the human kidney.

Human high (H) and low (L) molecular weight kininogens are encoded by distinct mRNAs derived by alternative splicing from a single kininogen gene. Previous studies have demonstrated the presence of L-kininogen but not of H-kininogen in the distal nephron structures of the kidney. Using the highly sensitive reverse transcriptase-polymerase chain reaction (RT-PCR) we have been able to demonstrate the expression of both H-kininogen mRNA and L-kininogen mRNA in kidney and liver. The presence of H- and L-kininogen antigen was shown immunohistochemically by applying specific antibodies that discriminate between the two types of kininogens. Immunoreactive kininogens were localized in the cortical and medullary collecting ducts. Our results indicate that both types of kinin-bearing kallikrein substrates are expressed in the human kidney where they might contribute to the suggested roles of the kallikrein-kinin system in the regulation of renal blood flow and electrolyte excretion.

Amino Acid Sequence↗
PubMed1996

A strategy for rapid and efficient DNA sequencing by mass spectrometry.

Two methods of solid-phase Sanger DNA sequencing followed by detection with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry are demonstrated. In one method, sequencing ladders generated on an immobilized synthetic template were resolved up to the 63-mer including the primer. Detection sensitivity and resolution were sufficient for sequence analysis in the given range. This approach is particularly suitable for comparative (diagnostic) DNA sequencing. A second method that has the potential for high throughput de novo DNA sequencing is also presented; it uses immobilized duplex probes with five-base single-stranded overhangs to capture an unknown DNA template serving as primers for Sanger DNA sequencing. The power of mass spectrometry is demonstrated not only by its very high speed, but also by its ability to identify sequences that are not readable using gel electrophoresis.

Base Sequence↗
PubMed1996

Conditions for single strand conformation polymorphism (SSCP)analysis with broad applicability: a study on the effects of acrylamide, buffer and glycerol concentrations in SSCP analysis of exons of the p53 gene).

We examined the influence of electrophoretic conditions on the detectability of small sequence alterations in DNA fragments by single strand conformation polymorphism (SSCP) analysis. Three acrylamide concentrations, 7.5, 14 and 20%, were selected, and all three gel types were prepared with four different Tris/borate/EDTA buffer concentrations. In addition, all these twelve gels were prepared both with and without 10% glycerol. All electrophoretic runs were performed at ambient temperature of 20-24 degrees C. The resulting 24 different electrophoretic conditions were used for the SSCP analysis of DNA fragments of exons 5, 7 and 8 of the human p53 gene; the results were evaluated primarily in relation to detectability of mutants. Six out of the 24 conditions permitted the detection of all mutants. For practical reasons, 14% acrylamide, 44.5 mmol/1 Tris, 44.5 mmol/1 boric acid, 1 mmol/1 EDTA, pH 8.0, with and without addition of glycerol was chosen as the most suitable. These "selected conditions" were applied in the SSCP analysis of an arbitrarily chosen set of mutant DNA fragments with single base exchanges,and all but one of seven mutants were detected in the gel system containing glycerol. Our results indicate that the set of "selected conditions" is of broad applicability, permitting the detection of even small sequence differences like single base exchanges with high reliability. It should prove especially useful in screening for unknown mutations.

Acrylamides↗
PubMed1996

Rapid and simple diagnosis of the two common alpha 1-proteinase inhibitor deficiency alleles Pi*Z and Pi*S by DNA analysis.

We describe a simple DNA-based method to assign the two common alpha 1-proteinase inhibitor (alpha 1-antitrypsin) deficiency alleles in the Pi-system (Pi*Z and Pi*S). Two sets of mutated primers are used in the polymerase chain reaction (PCR), followed by a restriction enzyme digest of the products. The mutated forward primers create a Taq I site only if the wildtype alleles (mostly M or subtypes) are present and not in the presence of the Pi*Z or Pi*S alleles. The reverse primers are mutated for an invariant Taq I site which serves as an internal control site in order to assure the completion of the restriction enzyme digest. The digested PCR products can be clearly resolved by 2.5% MetaPhore-agarose gel electrophoresis. This simple PCR probing of the most common alpha 1-antiproteinase deficiency alleles can be routinely applied either to samples showing quantitatively decreased alpha 1-antiproteinase values in serum or to blood spots of Guthrie cards used for mass screening purposes. In addition, this method may provide the opportunity for a simple, rapid, and reliable prenatal diagnosis of alpha 1-antiproteinase deficiency in special cases.

Alleles↗
PubMed1996

In vivo studies on Aujeszky's disease virus mutants.

We report the construction and in vivo analysis of three recombinant Aujeszky's disease virus (ADV) strains containing mutations at three different loci of the genome. Mutant vE16lac was generated by deleting of 2976 bp DNA fragment which covers 1851 bp of the right arm of UL component, the UL-US junction, the "a" element of the internal repeat (IR) region and a putative LAT promoter. Mutant vRRlac was generated by deletion of a 1805 bp fragment from the coding region of the large and small subunits of ribonucleotide reductase gene (rr). The third mutant, vTKlac, was constructed using insertional mutagenesis of the thymidine kinase gene (tk). In the constructed mutants a lacZ gene expression cassette was either inserted into the target gene (vTKlac) or replaced the deleted DNA segment (vE16lac, vRRlac). Constructed recombinant viruses were analyzed by infecting pigs and monitoring the virus excretion from nasal fluid and disease symptoms. Tissue specimens were collected for virus isolation and pathological examination. Strains vTKlac and vRRlac retained the ability to establish an infection, but showed reduced replication efficiency in the respiratory tract and were unable to attack the central nervous system (CNS) of pigs. Thus, both deletions induce significant attenuation of the virus measured by decrease of virulence in infected pigs. Strain vE16lac showed disease symptoms similar to that of wild type and could be detected in the CNS of pigs.

Animals↗
PubMed1995

Association of X-linked adrenoleukodystrophy with HLA DRB1 alleles.

Inflammatory demyelination in the central nervous system in the childhood cerebral phenotype of X-linked adrenoleukodystrophy (X-ALD) bears resemblance to that of multiple sclerosis. With a view to an association of HLA class II genes, specifically HLA-DRB1 subtype DRB1*15 to multiple sclerosis we investigated the HLA class II DR haplotype in 29 unrelated X-ALD patients including 17 childhood cerebral phenotype patients. Our results did not show an association of DRB1*15 and X-ALD, but disclosed a significant association of HLA DRB1*16 alleles and X-ALD in general. This finding suggests that in addition to the X-chromosomal ALD gene an autosomal gene linked to the HLA class II region is involved in the pathogenesis of X-ALD. This gene should affect a pathomechanism common to all ALD variants, such as defective peroxisomal metabolism of very long chain fatty acids.

Adrenoleukodystrophy↗
PubMed1995

The human bradykinin B2 receptor gene: full length cDNA, genomic organization and identification of the regulatory region.

Hybridization of Northern blots with a probe corresponding to the coding region of the bradykinin B2 receptor revealed a single transcript of approximately 4.0 kb. Using the same probe, we detected a 2.6 kb human cDNA clone that overlapped 103 bp with the 3' end of the known coding region and contained a classical polyadenylation site and a polyA tail. The gene for the human B2 receptor was isolated from a human placenta genomic library. Analysis of several genomic lambda clones indicated that the B2 receptor gene is organized in three exons. Genomic Southern analysis revealed the B2 receptor to be encoded by a single copy gene. In situ hybridization showed that the gene is located on chromosome 14q32. By testing different putative regulatory fragments in a luciferase reporter assay, a gene activating function of the 5' upstream region of exon 1 was demonstrated.

Animals↗
PubMed1995

Identification of polymorphic sites of the human bradykinin B2 receptor gene.

The characterization of the genomic organization of the B2 bradykinin receptor gene enabled us to systematically search for polymorphic markers in this gene in a South German cohort (N = 179). We identified at least three polymorphic sites in each of the three exons existing: (i) in exon 1 next to the promoter region, a tandem repeat polymorphism consists of three common alleles, (ii) in exon 2 at nucleotide position 181 of the cDNA a C to T transition leads to an aminoacid substitution from arginine to cysteine in the receptor protein at position 14 (R14C), and (iii) a more complex repeat polymorphism, located in the 3' not-translated region of exon 3, comprises at least two common alleles and two rare variants. These new genetic markers provide valuable tools to elucidate a potential role of a hereditary dysfunction of the B2 bradykinin receptor gene in disorders such as hypertension or ischemic heart disease.

Alleles↗
PubMed1995

Characterization of two stop codon mutations in the galactose-1-phosphate uridyltransferase gene of three male galactosemic patients with severe clinical manifestation.

Classical galactosemia, which is caused by deficiency of galactose-1-phosphate uridyltransferase, is characterized by acute problems of hepatocellular dysfunction, sepsis, cataracts and failure to thrive. Galactose limitation reverses these symptoms immediately; however, the long-term complications, such as mental retardation and ovarian failures are major problems in most of these patients. In order to investigate the molecular basis for phenotype variation in galactosemia, we have screened the most common mutation in the GALT gene, Q188R. We have further examined those patients who are heterozygous for Q188R or negative for this mutation by SSCP analysis and direct sequencing. In three male patients, we have identified, for the first time, two stop-codon mutations in the GALT gene, G212X (exon 7) and E340X (exon 10). Two patients of 8 and 28 years of age, respectively, who are compound heterozygotes for Q188R and G212X, have severe mental retardation and their general clinical condition is more severe than that of patients with missense mutations. The third patient, who is 8 years of age and who is homozygous for E340X, the N314D polymorphism and a silent substitution L218L, presents with a relatively normal physical and mental condition to date.

Adult↗
PubMed1995

Characterization of mutants of the vitamin D-binding protein/group-specific component: molecular evolution of GC*1A2 and GC*1A3, common in some Asian populations.

A well defined polymorphism of vitamin D-binding/group-specific component (GC) residues in exon 11. To characterize the molecular basis of GC*1A2 and GC*1A3, common in some Asian populations, we analyzed all coding exons amplified by the polymerase chain reaction. GC*1F was divided into GC*1FC and GC*1FT by a C-T transition in the third nucleotide of the codon (TGC/T) for cysteine283 in exon 8. The sequencing of exons 8 and 11 showed that GC*1A2 and GC*1A3 had occurred on a GC*1FC genetic background. They also shared a substitution of cysteine (TGC) for arginine (CGC) at position 429 in exon 11. GC*1A2 was characterized by having glycine (GGC) instead of serine (AGC) at position 335 in exon 9. GC*1A2 evolved from GC*1FT by three mutational events, i.e. GC*1FT-->GC*1FC-->GC*1A3-->GC*1A2. No evidence was obtained for the existence of the duplicated gene GC*1F.1A2 suggested by isoelectric focusing (IEF) of serum samples. The idea that the characteristic banding pattern of GC*1F.1A2 after IEF results from partial formation of a disulfide bond in the additional cysteine at position 429 is discussed.

Alleles↗
PubMed1995

A novel sequence polymorphism in exon 8 of the human vitamin D-binding protein (GC) gene in an African population.

A novel sequence polymorphism due to a T to C transition at the third nucleotide of the codon for Cys283 of the vitamin D-binding protein (GC) gene assigned to chromosome 4q13-4q21.1 was revealed by sequence analysis. Population studies by single strand conformation polymorphism (SSCP) analysis showed this GC-283.3 site was polymorphic in a Black African population but monomorphic in a European population.

Base Sequence↗