Biomedical subjects

C Rittner

Publications and source records attributed to C Rittner.

At least 37 records · Page 2Linked to original sources

PubMed1995

Identification of an unknown corpse by means of computed tomography (CT) of the lumbar spine.

For the first time, a case is described in which an unknown corpse is identified by the comparison of antemortem and postmortem computed tomographic (CT) images. A posterolateral disc herniation at L5-S1 on the right side, Schmorl's nodes and a lucency in the ilium were found in identical locations in each case. Additionally there were characteristic morphological similarities in the vertebral bodies, spinous processes, transverse processes and neural arches. In CT identification, as in conventional radiographic identification, one must try to reproduce comparable scanning conditions and images because apparent differences in the roentgenological morphology can occur as a result of different gantry angles or slice thicknesses.

Expert Testimony↗

PubMed1994

Medical law and ethics in abortion--results of a comparative study in Japan and Germany.

Based on interviews with 180 women in Ube, Japan, and 200 woman in Mainz, Germany, the authors report on different opinions on reproductive medicine, with particular reference to abortion. In the light of the historical German-Japanese legal relationship, the latest ruling of the Bundesverfassungsgericht on abortion is discussed, with some remarks from J. Reiter on its social ethics.

Abortion, Induced↗

PubMed1994

Calculation of paternity probabilities from multilocus DNA profiles.

We describe a procedure for evaluation of paternity evidence from multi-locus DNA probe patterns. A computer program abstracts a "+/-" notation description from the multilocus profile and then calculates a paternity index based on observed phenotypic fragment frequencies. The biostatistical evaluation considers only bands found in the child and missing from the mother--a simplified approach that is at once robust and conservative. Mutations are of course taken into account. Particular features lending objectivity to the interpretation include computer reading and matching decisions, and specific recognition and statistical compensation for ambiguities ("faint orphans").

Chromosome Banding↗

PubMed1994

Polymorphism of the complement C8A and -B genes in two families with C8 beta deficiency and neisserial infections.

Serum samples from members of two Italian families with complement C8 beta deficiency were studied by SDS-PAGE under nonreducing conditions and by IEF. The proband of family I had suffered from two episodes of purulent meningitis and two of her uncles had suffered from only one episode, while the proband of family II had suffered from three different episodes. In contrast to previous findings, where C8 beta deficiency was cosegregating with C8A (alpha-gamma) allotype A, the proband of family II had the C8A allotype B. In addition, in one of her sons a novel variant of the C8 beta chain was detected. Studies at the DNA level in family I, using a recently described PCR system, demonstrate the presence of a C-T exchange, which creates a stop codon in exon 9 of the C8B gene, as cause for the C8 beta deficiency. The mutated allele does not carry the TaqI polymorphic restriction site located in intron 11 of the C8B gene. These findings provide evidence for multiple recombination events within the genetic region of the defective C8B gene.

Adult↗

PubMed1994

A new PCR-based typing of the Rodgers and Chido antigenic determinants of the fourth component of human complement.

The Rodgers (Rg) and Chido (Ch) blood groups are antigenic determinants of the fourth component of human complement C4. They are associated with the two isotypes of C4, C4A and C4B, respectively. They serve as markers to distinguish C4A from C4B as well as for the definition of subtypes of common and rare allotypes. As an alternative to the serological typing method using human alloantisera, a PCR typing procedure with sequence-specific primers (PCR-SSP) was designed. The method was tested on selected DNA samples from individuals with well-defined C4 allotypes. No false-positive or false-negative typing results were obtained and all the determinant combinations could be distinguished. The PCR genotyping allowed the detection of all Rg/Ch sequence determinants of each isotype. Thus, reverse antigenicity could also be established in the presence of other C4 allotypes without a segregation study. To exclude the possibility that PCR-typed determinants originate from a non-expressed C4 null gene, a sequence-specific PCR was established detecting a 2-bp insertion in exon 29 described previously as a cause for C4A non-expression. PCR Rg/Ch genotyping provides a fast and efficient method for routine typing in HLA haplotype and disease association studies.

Alleles↗

PubMed1994

A combined study of human complement C7 IEF and C7 M/N polymorphisms in the Chinese Han population.

Two polymorphisms of human complement C7 (IEF and M/N) have been studied in the Han population from Chengdu, People's Republic of China. One was determined by polyacrylamide gel isoelectric focusing (IEF) of neuraminidase-treated EDTA plasma, whereas the other was performed by a combination of two ELISAs using a C7-allospecific monoclonal antibody or polyclonal C7-specific IgG as coating antibodies. In 121 Chinese subjects IEF patterns of C7 were classified into three common and four rare phenotypes. The C7 IEF allele frequency estimates for C7*1, C7*2, C7*3, C7*4 and C7*7 were 0.831, 0.095, 0.045, 0.025 and 0.004, respectively. The C7 M/N typing in 113 Chinese individuals revealed the following allele frequencies: C7*M = 0.805, C7*N = 0.195. Allelic associations between C7 IEF alleles and the C7 M/N alleles are also discussed.

Asian People↗

PubMed1993

Genetic basis of human complement C8 beta deficiency.

The eighth component of human complement (C8) is a serum protein consisting of three chains (alpha, beta, and gamma) and encoded by three different genes, C8A, C8B, and C8G. C8A and C8B are closely linked on chromosome 1p, whereas C8G is located on chromosome 9q. In the serum the beta subunit is non-covalently bound to the disulfide-linked alpha-gamma subunit. Patients with C8 beta deficiency suffer from recurrent neisserial infections such as meningitis. Exon-specific polymerase chain reaction (PCR) amplification with primer pairs from the flanking intron sequences was used to amplify all 12 C8B exons separately. No difference regarding the exon sizes was observed in a C8 beta-deficient patient compared with a normal person. Therefore, direct sequence analysis of all exon-specific PCR products from normal and C8 beta-deficient individuals was carried out. As a cause for C8 beta deficiency, we found a single C-T exchange in exon 9 leading to a stop codon. An allele-specific PCR system was designed to detect the normal and the deficiency allele simultaneously. Using this approach as well as PCR typing of the Taql polymorphism located in intron 11, five families with 7 C8 beta-deficient members were investigated. The mutation was not found to be restricted to one of the two Taql RFLP alleles. The mutant allele was observed in all families investigated and can therefore be regarded as a major cause of C8 beta deficiency in the Caucasian population. In addition, two C8 beta-deficient patients were found to be heterozygous for the C-T exchange. The molecular basis of the alleles without this point mutation also causing deficiency has not yet been defined.

Base Sequence↗

PubMed1993

[Correlation between an occupational accident and death 55 years later. Evidence despite 2 1/2 months burial--a contribution to the value of insurance medicine autopsy also after exhumation].

Analysis of 24 autopsy cases ordered by insurances and performed at the Institute of Legal Medicine, Johannes Gutenberg University, Mainz (FRG), in the years from 1985 to 1991 revealed that even if there was a long period of time between accident and death (average: 20.3 years; maximum: 55 years) and in cases of exhumation necropsy was a useful tool in checking the relative's claim to insurance premium. Nevertheless post mortem examination should be performed as soon as possible to ensure evident pathomorphological findings and to avoid unjustified waiting periods with economical problems (e. g. case report: 78 years old widow couldn't pay electricity and call charge; she had a right to a pension due to an accident of her husband 55 years before, proved by exhumation 2 1/2 months after death.

Accidents, Occupational↗

PubMed1993

The human complement component C8B gene: structure and phylogenetic relationship.

The eighth component of human complement (C8) is a serum protein that consists of three chains (alpha, beta and gamma), encoded by three separate genes, viz., C8A, C8B, and C8G. In serum, the beta-subunit is non-covalently bound to the disulfide-linked alpha-gamma subunit. Using a full-length C8 beta cDNA probe, we isolated several clones from human genomic lambda DNA libraries. Four lambda clones covering the complete cDNA sequence were characterized by TaqI restriction mapping and were "shotgun" subcloned into M13. C8 beta-cDNA-positive clones were partially sequenced to characterize the 12 exons of the gene with sizes from 69 to 347 bp. All intron-exon junctions followed the GT-AG rule. By using polymerase chain reaction (PCR) primers located in the adjacent intron sequences, all 12 exons of the C8B gene could be amplified from genomic DNA. All fragments showed the expected sizes. The sizes of eight introns could be determined by using primer pairs that amplified two exons and the enclosed intron, and by restriction mapping. These analyses and the insert sizes of the genomic lambda clones indicate that the C8B gene has a total size of approximately 40 kb. The polymorphic TaqI site of the C8B gene localized in intron 11 could be demonstrated by direct restriction fragment analysis of a PCR fragment containing exons 11 and 12, and the enclosed intron 11. Homology comparison of the C8B gene with C8A and C9 on the basis of the exon structure confirmed the ancestral relationship known from the protein level.

Base Sequence↗

PubMed1993

Human complement C81 (C8 A) polymorphism: detection and segregation of new variants.

In addition to the earlier detected C81(A) rare variants A1, A2 (now A3) and B1 (now B2), six new rare variants (C81 A2 new, A4, A5, A6, M1 and B1new) are described within the polymorphism of the eighth component of human complement (alpha-gamma chain subunit). Except for A3, all rare C81 A variants are only detected by isoelectric focusing, and not by SDS polyacrylamide gel electrophoresis (PAGE), in the alpha-gamma subunit. In one individual out of approximately 700 individuals studied, a reversed position of the common allele (B vs A) was observed by SDS PAGE and the isofocusing technique. The segregation of A1, A3 and A4 could be followed in putative father/child combinations.

Alleles↗

PubMed1993

Experience with the PCR-based HLA-DQ alpha DNA typing system in routine forensic casework.

The results of HLA-DQ alpha typing from 42 routine forensic cases using the polymerase chain reaction (PCR) were analyzed regarding the reliability, discrimination efficiency and informative value of this system in a given case. The cases included stain typing from a variety of different substates, i.e. blood and semen stains, mixed body fluids, single hairs, cigarette butts, material from fingernail scratches, as well as identification and paternity cases on postmortem and fixed tissue. A total of 125 individual stain and tissue samples were included. PCR amplification was achieved in 70% of these samples. In cases with mixed body fluids, e.g. sperm and vaginal cells from rape cases, DQ alpha typing was always carried out successfully. However, only approx. 42% of all samples that could be typed were relevant regarding the inclusion or exclusion of a suspect. This was mostly due to the limited number of alleles that can be typed at the HLA-DQ alpha locus or to the fact that the stain or hair samples did not originate from the perpetrator, but from the victim or from other persons not related to the crime.

DNA↗

PubMed1993

Genetic basis of human complement C4A deficiency. Detection of a point mutation leading to nonexpression.

The fourth component of the human complement system (C4) is coded for by two genes, C4A and C4B, located within the MHC. Null alleles of C4 (C4Q0) are defined by the absence of C4 protein in plasma. These null alleles are due either to large gene deletions or to nonexpression of the respective genes. In a previous study, evidence was obtained for nonexpressed defective genes at the C4A locus, and for gene conversion at the C4B locus. To further characterize the molecular basis of these non-expressed C4A genes, we selected nine pairs of PCR primers from flanking genomic intron sequences to amplify all 41 exons from individuals with a defective C4A gene. The amplified products were subjected to single-stranded conformation polymorphism (SSCP) analysis to detect possible mutations. PCR products exhibiting a variation in the SSCP pattern were sequenced directly. In 10 of 12 individuals studied, we detected a 2-bp insertion in exon 29 leading to nonexpression due to the creation of a termination codon, which was observed in linkage to the haplotype HLA-B60-DR6 in seven cases. In one of the other two individuals without this mutation, evidence was obtained for gene conversion to the C4B isotype. The genetic basis of C4A nonexpression in the second individual is not yet known and will be subject to further analysis.

Amino Acid Sequence↗

PubMed1993

Genetic polymorphisms of the A and B subunits of coagulation factor XIII in the Chinese population.

Coagulation factor XIIIA and XIIIB polymorphisms in a random population sample from Chengdu in southwest China (n = 121) were studied using isoelectric focusing in polyacrylamide gels followed by immunoblotting with enzyme immunoassay. The allele frequencies were as follows: FXIIIA*1 = 0.8719, FXIIIA*2 = 0.1240, FXIIIA*3 = 0.0041; FXIIIB*1 = 0.2727, FXIIIB*2 = 0.0165, FXIIIB*3 = 0.7107. The distribution of phenotypes of FXIII agrees with the Hardy-Weinberg equilibrium. Comparing these allele frequencies with those reported in other populations, it was found that the allele frequencies of FXIIIA*1 and FXIIIB*3 in the Chinese population were higher.

Alleles↗

PubMed1992

Application of DNA techniques for identification using human dental pulp as a source of DNA.

Dental pulp tissue could be obtained in most cases from materials obtained under experimental conditions and from forensic casework (air accidents, burned and putrefied bodies). Teeth extracted during dental treatment (n = 30) were stored for 6 weeks and 4 years at room temperature. In addition teeth (n = 10) extracted from jaw fragments that had been stored for 15 years at room temperature, and teeth extracted post mortem from actual identification cases (n = 8) were investigated. Following extraction from dental pulp tissue the DNA concentration was measured by fluorometry. The amount of DNA obtained from the dental pulp tissue of a single tooth varied from 6 micrograms to 50 micrograms DNA. In most cases high molecular weight DNA was still present although the major portion consisted of degraded DNA. Genomic dot blot hybridization for sex determination using the biotinylated repetitive DNA probe pHY 2.1 was performed and sex was correctly classified in all cases using 50-100 ng target DNA. PCR typing of the HLA-DQ alpha and ApoB 3' VNTR systems from dental pulp tissue DNA was in agreement with the results obtained from blood, bloodstains, or lung tissue. In addition, Southern blot analysis of selected samples using the single locus VNTR probe pYNH24 was successfully performed. In all cases the DNA recovered from dental pulp was unsuitable for multilocus probe analysis.

Blotting, Southern↗

PubMed1992

Identification of the recombination site within the steroid 21-hydroxylase gene (CYP21) of the HLA-B47,DR7 haplotype.

The HLA haplotype A3-Cw6-B47-C4A91-BQ0-DR7 is associated with congenital adrenal hyperplasia (CAH), since it only carries the dysfunctional steroid 21-hydroxylase A pseudogene as well as the 5' adjacent complement C4A gene. The recombination site leading to the deletion of the complement C4B and steroid 21-hydroxylase B genes in this haplotype was studied by determining the 21-hydroxylase genomic DNA sequence in comparison to the standard CYP21A- and CYP21B-specific sequences. A 200-bp region between exons 7 and 8 was identified as a possible recombination site. Thus the deleted area comprises the 3' end of the CYP21A pseudogene, the entire C4B gene and the 5' end of the CYP21B gene. The findings were confirmed by PCR amplification of a 1.8-kb fragment of the CYP21 gene. This PCR system is specific for CYP21A/B recombinant genes and may be used for screening among CAH patients carrying this type of deletion.

Adrenal Hyperplasia, Congenital↗

PubMed1991

HLA DRw8 and complement C4 deficiency as risk factors in primary biliary cirrhosis.

HLA class I, II, and III alleles were investigated in 25 consecutive unrelated German patients with primary biliary cirrhosis and in two families with two primary biliary cirrhosis patients in each. In primary biliary cirrhosis patients, HLA class I antigens did not differ significantly from in health controls. For HLA class II antigens, a highly significant increase of HLA DRw8 was found in patients with primary biliary cirrhosis compared with controls. Thirty-six percent vs. 3.6% were DRw8 positive [relative risk = 15.28; P (corrected) = 0.00013]. The genetic typing of HLA class III alleles revealed an increased incidence for C4AQ0 alleles [72% vs. 34.5%, relative risk = 4.89: P (corrected) = 0.0056]. A highly significant proportion of primary biliary cirrhosis patients carrying both DRw8 and C4A-Q0 alleles (relative risk = 183.75; P = 9.7 x 10(-7)) were found. In one family, a mother and her daughter had primary biliary cirrhosis, both sharing the major histocompatibility complex haplotype HLA-A1, -B8, -DR3, -C4AQ0B1. In the other family, two sisters with primary biliary cirrhosis shared the major histocompatibility complex haplotype HLA-A24, -B8, -DRw8, -C4A4B2. These studies contribute to the further elucidation of the immunogenetic background of primary biliary cirrhosis.

Alleles↗

PubMed1990

Null alleles of human complement C4. Evidence for pseudogenes at the C4A locus and for gene conversion at the C4B locus.

The two genes for the C4A and C4B isotypes of the fourth component of human complement are located in the MHC class III region. Previous studies have demonstrated the unusual expression of C4 genes in the form of aberrant or duplicated haplotypes. Null alleles of C4A or C4B (AQ0 or BQ0) have been defined by the absence of gene products and occur at frequencies of 0.1-0.3. However, only some C4 null alleles are due to gene deletions, the remainder were thought to be nonexpressed genes. We have analyzed the C4 gene structure of 26 individuals lacking either C4A or C4B protein. The DNA of individuals with apparently nonexpressed C4 genes was tested for the presence of C4A- and C4B-specific sequences using restriction fragment analysis and isotype-specific oligonucleotide hybridization of DNA amplified by polymerase chain reaction. All nondeleted AQ0 allels had C4A-specific sequences and may thus be described as pseudogenes, whereas the nondeleted BQ0 alleles had C4A-instead of C4B-specific sequences. Gene conversion is the probable mechanism by which a C4A gene is found at the second C4 locus normally occupied by C4B genes.

Alleles↗

PubMed1990

Chromosomal aberrations in patients with primary biliary cirrhosis.

Chromosomal aberrations in untreated lymphocyte cultures, bleomycin (BLM)-induced aberrations and sister chromatid exchanges (SCE) in the peripheral blood lymphocytes of 11 patients suffering from primary biliary cirrhosis (PBC) and 14 matched control individuals were analysed. The lymphocytes of the PBC patients had on average a lower mitotic index (2.3) compared with controls (3.5) in the untreated cultures. The mean baseline rate of aberrations of the cultured lymphocytes of the patients was 5.3 aberrations per 100 metaphases (%); this was significantly different (P = 0.0291) from that of the controls with a mean of 2.3%. In lymphocytes of the patients and controls, most of the aberrations observed took the form of gaps; there was an almost equal breakage rate in both groups (0.5% and 0.4%, respectively). The average number of mitoses with aberrations in the PBC patients studied was double that of the controls (4.9% and 2.3% respectively, P = 0.0323). The mean number of the BLM-induced aberrations was 54.0% and 27.7% for the lymphocytes of the patients and controls, respectively. The mean number of the aberrant mitoses in the BLM cultures was 6 times higher than that of the untreated cultures for both groups, 25.7% and 14.6% respectively (P = 0.018). The chromosomal distribution of baseline and induced aberrations was not random. The PBC patients had a mean number of 8.7 SCE per mitosis, which was significantly higher than the SCEs in the controls (6.3 SCE per mitosis; P = 0.0156). The evidence suggests that the chromosomes of the lymphocytes of PBC patients may be less stable than those of the control individuals in this study.

Adult↗