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Biomedical subjects

K Kayser

Publications and source records attributed to K Kayser.

At least 181 records · Page 10Linked to original sources
PubMed1975

Thrombosis and intracranial tumors.

334 necropsy reports of intracranial neoplasm from an autopsy material over 13 years were reviewed to study the relationship of intracranial tumors to vascular thrombosis. The incidence of venous thrombosis in intracranial tumors was found to be 27.5% while that of a control group without malignancies taken at random from the autopsy material was 17%. The difference gives a statistical significance of P less than or equal to 0.05. The parameters of sex, surgical intervention, the malignancy and the histological type of the tumor apparently dod not affect thrombus formation to a statistically significant degree. There is increased thrombosis frequency with increasing age. The presence of hemiparesis or hemiparalysis does not affect the incidence of thrombosis. However, it determines to a great degree the lateralization of the thrombus.

Adolescent↗
PubMedDate not supplied

Rapid microwave fixation--a comparative morphometric study.

Tissue blocks taken from healthy human lung tissues, from primary bronchial carcinoma and from mediastinal and hilar lymph nodes were placed in the following solutions: Tris buffer; buffered formalin (0.5%, 1%, 7%); 0.1 mol NaCl; distilled water; DMSO (1%, 10%, 20%); acetone (10%); methanol (50%, 80%, 100%); glutaraldehyde (2.5%), and fixed by use of a commercial microwave oven. Tissue blocks obtained from the same surgical specimens were fixed in 7% buffered formalin for 24 h for comparison. Conventional and microwave-fixed tissue was embedded in paraffin, and stained with haematoxylin and eosin. Fifteen specimens of each group and each solution were examined by light microscopy. Minimum diameter and area of 100 nuclei of each specimen were measured interactively. Histomorphological sections fixed with Tris buffer in a microwave oven revealed best morphological results showing more contrast in chromatin distribution of nuclei and 'opening' of interstitial lung capillaries in comparison to conventional formalin-fixed specimens. No statistically significant differences in area and minimum diameter of nuclei between the different groups were found. Microwave fixation using Tris buffer is a time-saving fixation method at least comparable to conventional formalin fixation. It is not accompanied by hazards to the environment that are unavoidable by formalin fixation.

Adenocarcinoma↗
PubMedDate not supplied

Microwave-assisted staining procedures in routine histopathology.

The use and practicability of microwave-assisted staining procedures in routine histopathology over more than three years has been evaluated. A domestic microwave oven was used to speed up the following staining procedures: Haematoxylin-Eosin (for frozen sections), Romanowsky-Giemsa, Periodic acid-Schiff (PAS), Ziehl-Neelson, Papanicolaou, Feulgen and Grocott--stain on buffered formalin fixed sections or cytologic smears. These staining procedures can be made highly reproducible providing; (1) Staining vessels are placed in the same position inside the oven; (2) Accurate timing in seconds is observed. Microwave-assisted staining procedures are equal to or even superior to those of the standard methods. Staining times can be reduced to 2%-10% of the conventional staining procedures. The basic staining protocols are presented.

Azure Stains↗
PubMedDate not supplied

Galectins-1 and -3 and their ligands in tumor biology. Non-uniform properties in cell-surface presentation and modulation of adhesion to matrix glycoproteins for various tumor cell lines, in biodistribution of free and liposome-bound galectins and in their expression by breast and colorectal carcinomas with/without metastatic propensity.

Protein (lectin)-carbohydrate (cellular glycoconjugate) recognition is operative in biochemical information transfer. Galectins constitute a family of endogenous galactoside-binding lectins with conserved features in the binding site. The members of this lectin category are assumed to be involved in cell adhesion and growth regulation. To assess to what extent the different modes of binding-site presentation and/or carbohydrate fine-specificities will affect aspects of galectin behavior, homodimeric cross-linking galectin-1 and monomeric chimeric galectin-3, with its collagenase-sensitive stalk linked to the carbohydrate-recognition domain, were investigated. Cell-surface expression of the two galectins and accessible galectin-binding sites on various tumor cell lines was ascertained by FACScan analysis. In particular, ligand accessibility for the two galectins differed for the tested cell line types. Binding of tumor cells to laminin and plasma or placental fibronectin was generally reduced by treatment of cells or matrix with galectins. Galectin-3 was more efficient than galectin 1 at impairing laminin's potency as matrix. Cell binding of galectin-1, on the other hand, proved on average more effective for blocking cell association to fibronectins after its preincubation with cell suspensions. Differences were also apparent in the biodistribution of the galectins, where an avian homolog of galectin- served as the control to distinguish effects of spatial and sugar-binding features. Histopathological analysis of lymph-node-negative and -positive breast and colorectal carcinomas (n = 180 including 60 metastatic lesions) indicated a correlation of either increased galectin-1 binding and reduced galectin-3 expression or reduced binding of both galectins with the occurrence of lymph node lesions. Together with data on the heparin-binding lectin, revealing reduced expression to be associated with a positive lymph-node status in the breast cancer group, these results can be interpreted to reflect cell-type-dependent requirements of galectin ligand presentation during the metastatic cascade. By introducing mammalian lectins to lectin-histochemical studies, the detection of quantitative differences in glycosylation brings an understanding of its cell biological significance one step closer.

Adenocarcinoma↗
PubMedDate not supplied

Use of postoperative information to predict mortality rates for patients who have long stays in the intensive care unit after coronary artery bypass grafting.

OBJECTIVE: To derive and evaluate prediction models for patients who had undergone coronary artery bypass grafting (CABG) and had a difficult postoperative course. DESIGN: Observational. SETTING: Midwestern hospital specializing in high-risk CABG procedures. PATIENTS: One hundred eighty-three patients who stayed at least 10 consecutive days in the intensive care unit after a CABG procedure. OUTCOME MEASURE: Death within 60 days of surgery. INTERVENTION: None. RESULTS: The final logistic regression prediction models included the following findings: pulmonary capillary wedge pressure, cardiac index, heart rate, urine output, positive end-expiratory pressure, blood urea nitrogen levels, and the arterial pressure of carbon dioxide. The model was able to stratify patients into four risk groups with observed 60-day mortality rates of 0.0% (n = 107), 21% (n = 39), 55% (n = 20), and 88% (n = 17). Preoperative patient information was not associated with prognosis for these patients. CONCLUSIONS: The findings suggest that a risk model that is specific for patients who have undergone CABG and is based on postoperative findings may provide useful prognostic information for patients who are having a difficult postoperative course.

Aged↗
PubMedDate not supplied

Neoglycoproteins with the synthetic complex biantennary nonasaccharide or its alpha 2,3/alpha 2,6-sialylated derivatives: their preparation, assessment of their ligand properties for purified lectins, for tumor cells in vitro, and in tissue sections, and their biodistribution in tumor-bearing mice.

Neoglycoproteins were prepared with chemoenzymatically synthesized complex biantennary N-glycan derivatives the nonreducing ends of which bear typical sequences found in glycoproteins. A chemically obtained biantennary heptasaccharide-azide was reduced and acylated with a 6-aminohexanoyl spacer. Elongation of the deprotected heptasaccharide using glycosyltransferases yielded a biantennary nonasaccharide with terminal galactose residues and two undecasaccharides terminating with alpha 2,6- or alpha 2,3-linked sialic acid. The free amino group of the spacer of these oligosaccharides was converted into an isothiocyanate. Its subsequent coupling to bovine serum albumin gave neoglycoproteins with a yield of 2.4-3.6 glycan chains per carrier molecule. This versatile synthetic pathway allows employment of a wide variety of complex-type glycans, which can be introduced to various test systems in vitro and in vivo to evaluate potential biomedical applications. Solid-phase assays with biotinylated sugar receptors revealed discriminatory binding properties of the three neoglycoproteins, especially for the mistletoe lectin. This direct assay system is preferable to the measurement of inhibitory capacities with respect to model ligands. Ligand type- and cell type-dependent quantitative differences in the binding properties of the probes were detected by FACScan analyses with a panel of tumor cell lines and by monitoring of staining in tissue sections for small cell and non-small-cell lung cancer and mesotheliomas. Biodistribution of iodinated neoglycoproteins in mice gave a prolonged presence of the sialylated probes in serum. Relative to the nonasaccharide, the uptake, especially of the iodinated neoglycoprotein with alpha 2,3-sialylated ligand chains, was clearly elevated in mice for kidneys and Ehrlich tumors. On the basis of the documented feasibility of these applications, it is concluded that the further elaboration of glycan chain variants by the described synthetic approach in combination with the given test panel is warranted to evaluate the potential of complex glycan chain-carrying neoglycoproteins for diagnostic and therapeutic purposes.

Animals↗
PubMedDate not supplied

Environmental exposure to tremolite asbestos: pleural mesothelioma in two Turkish workers in Germany.

This report concerns two Turkish immigrant workers, aged 50 and 59, who developed histologically confirmed diffuse malignant mesothelioma in the absence of obvious occupational exposure to asbestos in Germany. Both patients had spent their childhood in central Anatolia, Turkey, where the presence of tremolite asbestos in the environment has been described. In both patients, the lung-dust burden showed a high concentration of amphibole fibers (186 x 10(6) resp. 59 x 10(6) per gram dry tissue), mainly classified as actionolite/tremolite fibers in scanning transmission electron microscopy. In both patients, the disease was thus attributed to early environmental exposure to tremolite asbestos.

Asbestos, Amphibole↗
PubMedDate not supplied

Thesaurus and information.

The quantitative and semantic aspects of information contained in thesauri are discussed with regard to three types of thesaurus: a thesaurus without classification, with a hierarchical structure, and with a facet structure. The optimal structure for a thesaurus, from the quantitative point of view, will depend on the number of diagnoses, the number of subdivisions and on the frequency of the diagnoses and structures. The authors show how semantic information can be computed semi-quantitatively if the structures in a diagnosis can be designated as 'more' and 'less' important for the diagnosis in question. TDM, ICD and SNOP are compared in quantitative terms. About 70-80% of diagnoses of the circulatory system and respiratory system, but only 20% of diagnoses of the nervous system, were found to be directly transferable between TDM and ICD. With the post-co-ordinated SNOP about 80% of TDM diagnoses could be codified.

Computers↗