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Biomedical subjects

B Herrmann

Publications and source records attributed to B Herrmann.

At least 55 records · Page 3Linked to original sources
PubMed1998

Genital infections among antenatal care attendees in Cape Verde.

In a cross-sectional study, 350 pregnant Capeverdian women were examined to assess the prevalence of Chlamydia trachomatis infection (CT), Neisseria gonorrhoeae infection (NG) and Bacterial vaginosis (BV). Among various analytic methods used, the polymerase chain reaction PCR (for NG, CT) yielded a higher detection rate than did direct microscopy or culture (NG), or direct immuno-fluorescence (CT). Since the PCR analytic of air-dried specimens is not hampered by harsh storage and transport conditions, it could serve to validate other detection methods where laboratory facilities are suboptimal. Among sociodemographic risk factors young age, and currently living alone, were significantly associated with infection.

Adult↗
PubMed1997

Comparison of the Ca2+-binding properties of human recombinant calretinin-22k and calretinin.

Calretinin-22k (CR-22k) is a splice product of calretinin (CR) found specifically in cancer cells, and possesses four EF-hands and a differently processed C-terminal end. The Ca2+-binding properties of recombinant human calretinin CR-22k were investigated by flow dialysis and spectroscopic methods and compared with those of CR. CR possesses four Ca2+-binding sites with positive cooperativity (nH = 1.3) and a [Ca2+]0.5 of 1.5 microM, plus one low affinity site with an intrinsic dissociation constant (K'D) of 0.5 mM. CR-22k contains three Ca2+-binding sites with nH of 1.3 and [Ca2+]0.5 of 1.2 microM, plus a low affinity site with K'D of 1 mM. All the sites seem to be of the Ca2+-specific type. Limited proteolysis and thiol reactivity suggest that that the C terminus of full-length CR, but not of CR-22k, is in close proximity of site I leading to mutual shielding. Circular dichroism (CD) spectra predict that the content of alpha-helix in CR and CR-22k is similar and that Ca2+ binding leads to very small changes in the CD spectra of both proteins. The optical properties are very similar for CR-22k and CR, even though CR-22k possesses one additional Trp at the C-terminal end, and revealed that the Trp residues are organized into a hydrophobic core in the metal-free proteins and become even better shielded from the aqueous environment upon binding of Ca2+. The fluorescence of the hydrophobic probe 2-p-toluidinylnaphtalene-6-sulfonate is markedly enhanced by the two proteins already in the absence of Ca2+ and is further increased by binding of Ca2+. The trypsinolysis patterns of CR and CR-22k are markedly dependent on the presence or absence of Ca2+. Together, our data suggest the presence of an allosteric conformational unit encompassing sites I-III for CR-22k and I-IV for CR, with a very similar conformation and conformational changes for both proteins. In the allosteric unit of CR, site IV is fully active, whereas in CR-22k this site has a 80-fold decreased affinity, due to the decreased amphiphilic properties of the C-terminal helix of this site. Some very specific Ca2+-dependent conformational changes suggest that both CR and CR-22k belong to the "sensor"-type family of Ca2+-binding proteins.

Calbindin 2↗
PubMed1997

Regulated redistribution of calretinins in WiDr cells.

The calcium-binding protein calretinin and the alternatively spliced form calretinin-22k are expressed in the colon adenocarcinoma cell line WiDr. As calcium-binding proteins have been implicated to play a role in cell cycle control, proliferation and differentiation, the levels and intracellular localisation of these two proteins were investigated. The addition of 1,25-dihydroxy vitamin D3 (10(-8) M) led to a transient translocation of calretinin-22k into the nucleus, while the cell growth was not affected. The addition of sodium butyrate and hexamethylene bisacteamide which induce markers of enterocyte differentiation decreased the levels of both forms of calretinin more than 90%. The agents which induced differentiation also led to a substantial inhibition of 3H-thymidine incorporation (>95%) which was paralleled by the disappearance of calretinins. We conclude that calretinin and calretinin-22k are associated with the proliferative status of WiDr cells and are almost completely absent in differentiated cells.

Journal Article↗
PubMed1997

[Molecular sex determination in skeletal remains of premature and newborn infants of the Aegerten, Switzerland, burial field].

The morphological and morphometrical analyses of skeletal remains usually give reliable access to the gender of mature individuals while the analyses of skeletal remains of immature individuals allocate only 70-90% of the individuals. However, the use of modern techniques like the Polymerase Chain Reaction (PCR) enables a sex identification also if fragmentary material or skeletal remains of children are investigated. The present study reconstructs the sex ratio of about 120 stillborn and neonate individuals of the burial place Aegerten, Switzerland. The morphometrical sex determination of the children suggests a large excess (about 60%) of female individuals. This finding was compared to the molecular sex identification. In order to perform a molecular sex identification aDNA was extracted from bone samples of the stillborn and neonate individuals. A standard phenol/chloroform extraction and a purification with a silica powder were carried out. Finally, the aDNA samples were amplified with a primer system for the amelogenin gene, that is located on the human sex chromosomes.

Bone and Bones↗
PubMed1997

[Detection of DNA single-copy sequences of prehistoric teeth. Site milieu as a factor for preservation of DNA].

DNA-extracts from prehistoric roots of teeth were analyzed by PCR to investigate microsatellite-systems. At the same time the x/y-chromosome specific system Amel A/B was investigated. The samples were collected from different burial conditions of similar age. Factors leading to limited DNA-degradation are given. For the first time reproducible Quadruplex-amplification on single-copy loci of prehistoric tissue was obtained in samples from the Lichtenstein-Cave, Kr. Osterode/Harz. Positive results are explained by low temperature in the burial site. In addition the results show that desiccation allows DNA-preservation but cannot protect the DNA from damage due to microbial origin. Microorganisms can destroy DNA-structures completely.

Burial↗
PubMed1997

[Reproducibility of aDNA typing].

The reproducibility of short tandem repeat (STR) amplification of aDNA extracts is limited by means of formation of artifacts during PCR. One of these artifacts, the so called allelic-dropout (failure of the amplification of alleles), may result in false-homozygote typing of a sample, if genotyping is based on the analysis of a single amplification product. 30 tooth- and bone samples collected from 17 individuals of three burial sites were investigated in a blind test. Using the polymerase chain reaction (PCR) the two independent segregating STR-loci HUMVWA and HUMTH01 were amplified. Corresponding to a mathematical estimation, multiple amplifications of each sample and genelocus were carried out. The results of this genotyping were compared intraindividually.

Bone and Bones↗
PubMed1997

[Classification of isolated skeletal elements using aDNA typing].

Analysis of ancient DNA of material found in the Lichtensteinhöhle, a burial site of the Younger Bronze Age has been used for the first time to assign isolated skeletal elements to corresponding individuals. The method involved DNA typing through amplification of five Short Tandem Repeat loci which are also used in forensic genetics for the determination of kinship and identification. From all of the examined bone samples DNA was successfully extracted and amplification by means of Polymerase Chain Reaction could be carried out. For the skeletal elements allelic profiles which are specific for an individual were set up. These profiles made it possible to recognize bones belonging to one individual. Elements which were not from this individual could be excluded with certainty by aDNA analysis.

Bone and Bones↗
PubMed1997

[Determination of kinship by aDNA analysis].

Molecular sex determination and aDNA typings were carried out on a group of five prehistoric individuals. Due to the burial situation and the individual ages the group was assumed to be a family consisting of the parents and three children. DNA was extracted from teeth and bone samples of all skeletons. The aDNA typings based on the PCR amplification of four different microsatellite DNA loci, so-called human short tandem repeats (STR). Results of the molecular sex determinations and allele determinations are presented and compared with morphological determinations. Up to now, the individual biological kinship could be verified for three of the individuals. This is the first proof of individual biological kinship on the molecular level for prehistoric individuals.

Adult↗
PubMed1997

[Prospects in prehistoric anthropology?].

Although Prehistoric Anthropology seems to flourish there are reasons for concern. Innovative developments as e.g. molecular techniques require rethinking of concepts and more staff and money, requirements for which Prehistoric Anthropology seems not to be well prepared to cope with. One way to drive back competition by foreign subjects could be to set up research co-operation.

Anthropology↗
PubMed1996

Detection of Neisseria gonorrhoeae from air-dried genital samples by single-tube nested PCR.

A single-tube nested PCR method was developed for the detection of Neisseria gonorrhoeae. The optimized assay had a detection limit of less than 0.3 cell. Five different storage conditions for gonococcal specimens were compared with respect to the PCR detection of bacteria. For air-dried gonococcal slides containing three bacteria, DNA was detected after 8 weeks at ambient temperature, and for slides containing 300 bacteria, DNA could be detected after 24 weeks at ambient temperature. Air-dried storage combined with analysis by the single-tube nested PCR and a commercially available PCR (Amplicor) was used to test 350 cervical specimens from women in the West African island nation of Cape Verde. The in-house PCR detected 17 cases of N. gonorrhoeae infection, while the Amplicor system detected 14 cases of N. gonorrhoeae infection. No specimen was negative by the in-house PCR assay and positive by the Amplicor PCR. This sensitive nested PCR assay, combined with air-dried storage, allows for the detection of gonococci when specimen storage and transport times are extended and freezing conditions are not available.

Female↗
PubMed1996

Differentiation of Chlamydia spp. by sequence determination and restriction endonuclease cleavage of RNase P RNA genes.

The amplification of DNA from Chlamydia trachomatis by PCR with degenerated primers yielded a 345-bp fragment of the putative RNase P RNA gene. From the deduced DNA sequence of this gene in C. trachomatis, a modified primer pair was designed. The primer pair was subsequently used to obtain the corresponding gene products from Chlamydia pneumoniae and Chlamydia psittaci. Sequence comparisons revealed similarities of 76.6% between C. trachomatis and C. pneumoniae, 79.5% between C. trachomatis and C. psittaci, and 84.7% between C. pneumoniae and C. psittaci. Furthermore, the three species were differentiated by fragment length polymorphism analysis after restriction enzyme cleavage of the PCR products. Sequence variations among 14 serotypes of C. trachomatis were confined to one purine base substitution in the putative RNase P RNA gene of lymphogranuloma venereum strains L1 to L3. Complete sequence similarity was found for nine strains of C. pneumoniae of different geographic origins. Taken together, our results indicate a possibility of the general application of this method in clinical bacteriology. Analysis of the secondary structures of the putative RNase P RNA genes from the different Chlamydia species suggested that a novel structural element in the domain of RNase P RNA is involved in base pairing with the 3'-terminal CCA motif of a tRNA precursor. This structure has not previously been found among RNase P RNAs of members of the division Bacteria.

Base Sequence↗
PubMed1996

Genital chlamydial infection among women in Nicaragua: validity of direct fluorescent antibody testing, prevalence, risk factors and clinical manifestations.

OBJECTIVE: To validate the performance of a direct fluorescence antibody (DFA) test and to determine the prevalence, risk factors and clinical manifestations of cervical chlamydia infection in different groups of women in Nicaragua. STUDY POPULATION: 926 women, 863 routine clinic attenders (mean age 27 years) and 63 sex workers (mean age 25 years) attending health centres in León, Corinto, Matagalpa and Bluefields. METHODS: Cervical specimens were examined using the Syva MicroTrak test system with a cut-off of 10 or more elementary bodies (EBs). The DFA results were validated by a one-step polymerase chain reaction (PCR) assay. Discordant results were further examined in nested PCR assays directed at two different target genes. An interviewer-administered questionnaire and a standard gynaecological examination were completed. RESULTS: Sensitivity of DFA was 80.1%, specificity 98.3%, and positive and negative predictive values 62.5% and 99.3%, respectively. Values were lower in locations where samples thawed because of electricity breaks and higher among sex workers. The majority of discordant results was confirmed as positive in nested PCR assays. Prevalence of cervical chlamydia infection based on positivity in DFA and/or PCR ranged from 2% among routine clinic attenders aged 35 years or older, to 8% among adolescent clinic attenders, and to 14% among sex workers. Among routine clinic attenders, young age (odds ratio [OR] 3.6, 95% confidence intervals [95% CI] 1.4-8.9 for women aged 15-19 years as compared with 1 in women 25 years of age or older) and use of oral contraceptives (OR 4.0, 95% CI 1.7-9.6) were the only statistically significant risk factors identified in multivariate logistic regression analysis. Presence of mucopurulent cervical discharge (OR 5.9, 95% CI 3.0-11.5) and presence of ectropion (OR 2.6, 95% CI 1.1-6.5) were the clinical signs independently associated with infection. CONCLUSIONS: Our results indicate that the DFA test was sensitive and specific while the performance of the PCR assay depends on adequate storage of samples. Genital C trachomatis infection is a common health problem among women in Nicaragua. The wide implementation of syndromic STD management algorithms together with health education programmes aimed at young people is the most promising approach to control STD in Nicaragua.

Adolescent↗
PubMed1996

Amplification of human short tandem repeats from medieval teeth and bone samples.

The suitability of typing hypervariable DNA loci for the genetic analysis of prehistoric populations is demonstrated for the first time. Alleles of the human short tandem repeat locus VWA31/A have been amplified from ancient teeth and bone samples derived from an early medieval burial site at Weingarten, Germany, using the polymerase chain reaction. The DNA results for 76 individuals reveal remarkable similarity of the allelic frequencies between the past and modern populations. A surplus of apparent homozygotes in the ancient population is most likely due to a stochastic problem of amplification of degraded DNA. Therefore technical obstacles for the application to ancient DNA were evaluated. The substantial perspectives of using microsatellite typing for the analysis of heritable diseases, determination of relatedness, and establishment of genealogies in prehistoric populations are outlined.

Alleles↗
PubMed1996

[Lipogranuloma of the orbit. Apropos of a case].

We present a case of orbital lipogranuloma with a supero-nasal retrobulbar localisation associated with axial proptosis and major choroidal thickening. No clinical sign of inflammation, neither orbital nor in the posterior segment, was revealed. The systemic work-up as well as paraclinical data were within normal limits. The diagnosis was made after histopathologic examination of the biopsy taken via superior orbit. Outcome was favorable following long-term systemic corticotherapy. Orbital lipogranuloma is a rare particular form of orbital pseudotumour of unknown etiology. It is characterized, histologically, by orbital fat necrosis. Pathogenesis remains controversial. The differential diagnosis includes iatrogenic lipogranulomas secondary to sinus surgery (paraffinoma), orbital granulomas in sarcoidosis and Wegener's disease and orbital lymphomas. The prognosis is usually good following treatment with steroids.

Adult↗