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Biomedical subjects

W Meyer

Publications and source records attributed to W Meyer.

At least 127 records · Page 7Linked to original sources
PubMed1997

Morphological heterogeneity of p53 positive and p53 negative nuclei in breast cancers stratified by clinicopathological variables.

The study was aimed to detect differences in nuclear morphology between nuclear populations as well as between tumours with different p53 expression in breast cancers with different clinicopathological features, which also reflect the stage of tumour progression. The p53 immunohistochemistry was performed on paraffin sections from 88 tumour samples. After the cells had been localised by means of an image cytometry workstation and their immunostaining had been categorised visually, the sections were destained and stained by the Feulgen protocol. The nuclei were relocated and measured cytometrically by the workstation. There were significant differences in the nuclear features between tumours as well as between nuclear populations with different p53 expression in the most subgroups. The variability of nuclear shape in tumour groups, classified by the tumour size or the lymph node status, increase with the p53 immunoreactive score, whereas in tumours grouped by the Bloom-Richardson grade features of the chromatin distribution were different between the p53 staining categories. The nuclear subpopulations showed differences in the amount and distribution of chromatin in most subgroups. The results demonstrate the relationship between the nuclear morphology and the p53 expression in different stages of breast cancers. The p53 status is an important factor of the biological behaviour but not the only one.

Breast Neoplasms↗
PubMed1997

Correlation between p53 status, DNA ploidy, proliferation rate and nuclear morphology in breast cancer. An image cytometric study.

The study was designed to detect differences in the nuclear morphology of tumours and tumour cell populations with different p53 expression in correlation with DNA ploidy and proliferation rate. The paraffin sections from routinely processed samples of 88 breast cancers were immunostained with the monoclonal p53-antibody DO-1. After localization and evaluation with a scoring system the sections were destained and stained by the Feulgen method. The nuclei were relocated automatically and measured by means of the image cytometry workstation. Significant differences between the tumours and tumour cell populations with different p53 expression were found in the euploid tumours as well as in the aneuploid tumours and in the breast cancers with a high proliferation rate. The breast cancers with a low immunoreactive score (IRS 1-4) differ from the negative cancers as well as from the cancers with a higher immunoreactive score (IRS 5-12). Evaluating the nuclear populations of the p53 positive cancers, there were differences in the features of the chromatin amount and distribution in the groups of the euploid breast cancers and in cancer with a high proliferation rate. In contrast, the nuclear populations of the aneuploid cancers did not show any differences in their nuclear morphology. The results showed the different impacts of the p53 expression, DNA ploidy and the proliferation rate on the nuclear morphology in breast cancer.

Adult↗
PubMed1997

DNA histogram interpretation based on statistical approaches.

Image cytometric DNA measurements provide data which are most often interpreted as equivalent to the chromosomal ploidy although the chromosomal and the DNA ploidy are not identical. The common link between them is the cell cycle. Therefore, if destined for DNA ploidy interpretations, the DNA cytometry should be performed on a population-oriented stochastic basis. Using stochastic sampling the data can be interpreted by applying the rules of stochastic processes. A set of statistical methods is given that enables a DNA histogram to be interpreted objectively and without human interaction. These statistics analyse the precision and accuracy of the entire measurement process. They give in error probabilities for accepting a measurement as reliable, for recognition of stemlines, stemline aneuploidy, and for evaluating so-called rare events. Nearly 300 image cytometric DNA measurements from breast cancers and rat liver imprints examples have been selected to demonstrate the efficiency of the statistics in each step of interpreting DNA histograms.

Aneuploidy↗
PubMed1997

Mitochondrial inner membrane bound Pet1402 protein is rapidly imported into mitochondria and affects the integrity of the cytochrome oxidase and ubiquinol-cytochrome c oxidoreductase complexes.

In vitro synthesized Pet1402 precursor protein is very rapidly and efficiently imported into isolated mitochondria. The import depends on a membrane potential and functional mtHsp70. The mitochondrial targeting sequence of the Pet1402 precursor protein is removed by the matrix processing peptidase MPP and the mature protein is firmly embedded in the inner mitochondrial membrane. The Pet1402 protein is required for the integrity of the cytochrome oxidase and ubiquinol-cytochrome c oxidoreductase complexes.

Biological Transport↗
PubMed1997

Immunohistochemical demonstration of transferrin and transferrin receptor in mammalian integument.

The present study demonstrates the distribution of transferrin and the transferrin receptor in the integument of eleven wild mammalian species using immunohistochemical methods. Both substances were regularly found in or near the peripheral cells of the sebaceous glands, especially of dense-haired animals. The transferrin receptor was also detectable in the epidermis, the secretory portion of tubular apocrine glands, and the outer epithelium of primary hair follicles. Transferrin as well as the transferrin receptor reacted strongly in macrophages of the papillary dermis only in the common seal. The results obtained are discussed with regard to possible biological functions in the skin of the substances demonstrated.

Animals↗
PubMed1997

The cardiovascular helix: a three-dimensional view of blood pressure and heart rate over time.

BACKGROUND: The baroreflex system plays an important role in the fast regulation of blood pressure. Conventional determination of baroreflex sensitivity either by pharmacological or by physical methods has proven cumbersome. Alternative approaches are based on continuously recording data of systolic arterial blood pressure (SAP) and heart rate, with evaluation by regression assessment or spectral analysis. Data selection for both methods results in various conflicts. We therefore developed a non-invasive method to evaluate baroreceptor functioning on the basis of a visual representation that would be independent of the restrictions related to regression and spectral analysis.METHODS: By plotting SAP and heart rate (measured by using a Finapres device) of 33 young men against time in a three-dimensional space, a helical structure could be visualized for subjects at rest as well as under stress. The shape of the helix was determined by the phase lag between SAP and heart rate and by the amplitude ratio. On the basis of this helix a model using two sinusoidal representations of SAP and heart rate parameterized the interaction between blood pressure and heart rate. The transfer function analysis was studied by means of a curve-fitting method similar to the Monte Carlo method. RESULTS: We found baroreceptor gain mode to be 9 ms/mmHg for subjects under stress and 11 ms/mmHg for subjects at rest. The values of phase lag between SAP and heart rate tended to gather around approximately 90 degrees. CONCLUSION: This method can be applied using even small sets of data over random periods of time.

Journal Article↗
PubMed1997

A computer-assisted method for the determination of hair cuticula patterns in mammals.

The study describes a rather simple, computer-assisted method for the determination of different mammalian species or groups with the aid of the cuticula pattern of guard hairs (primary hairs) following SEM presentation. The method is based on an image analysis program developed for metallographic investigations, and includes the evaluation of five parameters (scale area, scale perimeter, number of scales per mm2, ratio of scale width and height, scale index). The scale index as a combination of scale numbers per square unit and the width/height ratio proved to be most useful for a relevant species or group identification of mammals according to the hair cuticula pattern.

Animals↗
PubMed1997

Nuclear image analysis of p53-positive and -negative cells in breast carcinoma.

OBJECTIVE: To detect differences in nuclear morphology in breast carcinoma cells with different p53 expression. STUDY DESIGN: Immunohistochemical reactions were performed on paraffin sections from 88 breast cancers with the monoclonal antibody DO-1. By means of an image cytometry workstation, 500 nuclei were localized and categorized in an immunohistochemical staining scoring system in each case. After destaining and Feulgen staining, the nuclei were relocated and measured by means of the workstation. RESULTS: P53-positive nuclei showed greater irregularity of the chromatin pattern and stronger granularity of the chromatin. There were also differences in the chromatin texture and nuclear shape between tumors different in their p53 expression. The p53-negative nuclear population from the p53-positive tumors and the whole nuclear population of the p53-negative tumors were morphologically different, also. CONCLUSION: Nuclear image analysis of immunohistochemically characterized cells allows further insight into the relationship of structure and function in malignant tumor cells.

Adult↗
PubMed1997

[Histochemical and biochemical studies of the circannual aspects of carbohydrate-dependent energy metabolism of the hair follicles of Turkish Angora goats].

Based on biopsy material, the study describes circannual variations of the accumulation of glycogen and organic carbon in the hair follicles. The results have been obtained by histochemical and biochemical methods. The histochemical-densitometric analysis of glycogen contents in the cells of the outer epithelial root sheath of the hair follicles exhibited a clear circannual course, with maxima in May/June and December, and minima in March and August. The content of organic carbon of the hair follicles was 7.61 micrograms/mg (max. 21.56 micrograms/mg) DW on average, with a corresponding annual cycle. The findings are discussed with regard to the energy metabolism of the hair follicle, especially in view of the fact that a biphasic cycle of hair growth becomes obvious in the Turkish Angora goat, a phenomenon that is obscured by other methods.

Animals↗
PubMed1997

Diagnostic and prognostic relevance of malignancy-associated changes in cervical smears.

OBJECTIVE: For approximately 15 years, malignancy-associated changes (MACs) have been consistently found by means of high-resolution cytometry in different tissues, especially in visually normal appearing cervical cells. Their biologic nature is not yet fully understood. The aim of this investigation was to assess the expression of MACs in cervical smears and to evaluate their prognostic relevance. STUDY DESIGN: This study was performed on normal intermediate cells obtained from 53 cytologically positive and 78 cytologically negative cervical smears. From a second sample, 31 cases showing negative cytology were selected for a prospective longitudinal study. Densitometric and texture features were generated, and MACs were described on the basis of multivariate discriminant analysis. RESULTS: Discrimination between positive and negative cases was possible, with a correct classification rate of approximately 80%. After a mean period of 29.5 months, we noted no statistically significant increase in the incidence of cervical intraepithelial neoplasia in the group of healthy but MAC-positive women as compared to those who were MAC negative. CONCLUSION: MACs were constantly expressed in the epithelium of the cervix. Although their prognostic relevance remains unclear, MACs play an important role in the effort to automate cervical cytology.

Adult↗
PubMed1996

Molecular evidence that the asexual industrial fungus Trichoderma reesei is a clonal derivative of the ascomycete Hypocrea jecorina.

The relationship of the important cellulase producing asexual fungus Trichoderma reesei to its putative teleomorphic (sexual) ancestor Hypocrea jecorina and other species of the Trichoderma sect. Longibrachiatum was studied by PCR-fingerprinting and sequence analyses of the nuclear ribosomal DNA region containing the internal transcribed spacers (ITS-1 and ITS-2) and the 5.8S rRNA gene. The differences in the corresponding ITS sequences allowed a grouping of anamorphic (asexual) species of Trichoderma sect. Longibrachiatum into Trichoderma longibrachiatum, Trichoderma pseudokoningii, and Trichoderma reesei. The sexual species Hypocrea schweinitzii and H. jecorina were also clearly separated from each other. H. jecorina and T. reesei exhibited identical sequences, suggesting close relatedness or even species identity. Intraspecific and interspecific variation in the PCR-fingerprinting patterns supported the differentiation of species based on ITS sequences, the grouping of the strains, and the assignment of these strains to individual species. The variations between T. reesei and H. jecorina were at the same order of magnitude as found between all strains of H. jecorina, but much lower than the observed interspecific variations. Identical ITS sequences and the high similarity of PCR-fingerprinting patterns indicate a very close relationship between T. reesei and H. jecorina, whereas differences of the ITS sequences and the PCR-fingerprinting patterns show a clear phylogenetic distance between T. reesei/H. jecorina and T. longibrachiatum. T. reesei is considered to be an asexual, clonal line derived from a population of the tropical ascomycete H. jecorina.

Ascomycota↗
PubMed1996

Nuclear image analysis of immunohistochemically stained cells in breast carcinomas.

Hitherto, the relationship between malignancy-associated morphological features in single tumour cells and the expression of markers indicating functional properties of these cells remained widely unknown. This study was aimed at describing differences in the size, shape and chromatin structure between tumour cells with different marker expression for progesterone receptors (PgR) and p53. Two series of breast cancers, consisting of 50 PgR-positive, and 39 p53-negative and 49 p53-positive mammary carcinomas, were investigated. The immunohistochemical staining was performed on paraffin sections using 3-amino-9-ethylcarbazole as the chromogenic substrate. By means of a cytometry workstation equipped with a computer-controlled motorised scanning stage, about 500 positive and negative tumour cells in each case were localised in the microscope and categorised by a scoring system for their staining intensity. After destaining, the tissue sections were Feulgen-stained. Then, all the tumour cells were relocated automatically and analysed by high resolution image cytometry. Among the numerous size, shape, and texture features used in the system, several variables of the nuclear contour and chromatin structure were found to be significantly different between the positive and negative tumour cell populations. Nuclei without PgR had more malignancy-associated morphological features than PgR-positive cells. Whereas p53-negative nuclei had a higher degree of regularity, their positive counterparts exhibited higher DNA ploidy values.

Biomarkers, Tumor↗
PubMed1996

[Comments on the suitability of swine skin as a biological model for human skin].

The use of porcine skin as a biomedical model for the human integument is discussed with reference to the literature. The epidermis and dermis can be used as a model as there are clear structural, functional and biochemical similarities with human skin layers. The actual utilization of porcine skin in dermatological research is reviewed. Practical difficulties are emphasized: in particular, the conditions required for use of porcine skin in experimental research, the most suitable breeds, and restrictions on biological interpretation of the results.

Animals↗
PubMed1996

Rapid identification of Candida species by DNA fingerprinting with PCR.

DNA polymorphisms in different species and strains of the genus Candida were assessed by amplifying genomic DNA with single nonspecific primers. This PCR method employed an arbitrary primer (the 10-mer AP3), a primer derived from the intergenic spacer regions (T3B), and the microsatellite primers (GTG)5 and (AC)10. Distinctive and reproducible sets of amplification products were observed for 26 different Candida and 8 other fungal species. The numbers and sizes of the amplification products were characteristic for each species. All yeast species tested could be clearly distinguished by their amplification patterns. With all primers, PCR fingerprints also displayed intraspecies variability. However, PCR profiles obtained from different strains of the same species were far more similar than those derived from different Candida species. By comparing species-specific PCR fingerprints of clinical isolates with those of reference strains, clinical isolates could be identified to the species level even if they could not be identified by routine biochemical methods.

Base Sequence↗
PubMed1996

Concordance of clinical and environmental isolates of Cryptococcus neoformans var. gattii by random amplification of polymorphic DNA analysis and PCR fingerprinting.

Sixty-one clinical and forty-nine environmental isolates of Cryptococcus neoformans var. gattii from Australia and the United States were analyzed by random amplification of polymorphic DNA (RAPD), using 12- to 22-mer primers in pairs, and/or PCR fingerprinting with a single primer derived from the microsatellite core sequence of the wild-type phage M13 (5' GAGGGTGGCGGTTCT 3'). Three major genetic profiles were identified by both typing techniques. A single RAPD profile (VGI) predominated among clinical isolates (44 of 48, 92%) and isolates from host eucalypts (45 of 45, 100%) from Australia. Of the 94 Australian isolates, 4 (3 clinical and 1 environmental) were assigned to profile VGII; 2 of these were recovered from patients and one was recovered from plant debris from Western Australia. Only one Australian clinical isolate was assigned to profile VGIII. A different distribution of RAPD profiles (four VGIII, two VGII, and one VGI) was found among four clinical and three environmental isolates from the United States. RAPD profiles of 8 of the 101 isolates studied revealed minor genetic variants, 4 of profile VGI and 4 of profile VGII. Genetic concordance between the majority of clinical and environmental isolates in Australia is consistent with the hypothesis that human disease is acquired from exposure to host eucalypts. Profiles of clinical isolates were independent of body site of infection, and profiles of all isolates were stable over time. Analysis by PCR fingerprinting confirmed the RAPD results. A second RAPD profile (VGII) was associated with infection in southwest Western Australia, where the two host eucalypts do not occur naturally. This raises the possibility of an alternative and as yet unidentified natural habitat of C. neoformans var. gattii. Our results indicate that RAPD analysis is a sensitive and useful method for investigating environmental sources of human infection with this biotype.

Australia↗
PubMed1996

Demonstration of NADPH-diaphorase (NO-synthase) in sebaceous glands of the mammalian integument, with remarks on the glandular capillary net.

The study demonstrates weakly to strongly positive reaction staining for NADPH-diaphorase/NO- synthase in the peripheral cells of sebaceous glands in the hairy skin of domesticated mammals. Additionally, the structure of the blood capillary system surrounding these glands is better elucidated. The results obtained are discussed in view of a modulatory action of NO generated by these enzyme activities, implying a direct influence of this substance on the contractile elements of gland-associated blood capillaries. In this way, a simple and self-regulatory mechanism to couple blood flow and glandular metabolism can be proposed.

Animals↗