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Biomedical subjects

W Kunz

Publications and source records attributed to W Kunz.

At least 19 recordsLinked to original sources
PubMed2005

Hofmeister effects in biology: effect of choline addition on the salt-induced super activity of horseradish peroxidase and its implication for salt resistance of plants.

The effect of choline addition on the salt-induced super activity of horseradish peroxidase (HRP) is investigated. HRP is presented in the literature as an efficient H(2)O(2) scavenger, and choline is the precursor of glycine betaine, a strong osmoprotectant molecule. Both the regulations of H(2)O(2) and of osmoprotectant concentrations are implicated in plants in order to counteract salt-induced cell damage. For the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), sulfate anions were found to play a crucial role in the increase of HRP activity. This induced super activity can be strongly reduced by adding choline chloride. The phenomena provide an example of physicochemical Hofmeister effects playing a central regulatory role in an important biological system.

Choline↗
PubMed2005

Unified concept of solubilization in water by hydrotropes and cosolvents.

In the present work hydrophobic dyes, i.e. disperse red 13 (DR-13; (2-[4-(2-chloro-4-nitrophenylazo)-N-ethylphenylamino]ethanol) and Jaune au gras W1201 (1H-indene-1,3(2H)-dione,2-(2-quinolinyl)), are solubilized in water with the help of different additives: acetone and 1-propanol as typical cosolvents, sodium xylene sulfonate (SXS) as a representative of a classical hydrotrope, sodium dodecyl sulfate (SDS) as a typical surfactant, and finally some "solvosurfactants" [ propylene glycol monoalkyl ether derivatives (CiPOj: i = 1, j = 1 and 3; i = 3, j = 1 and 2; i = 4 and tertio-butyl, j = 1) and 1-propoxy-2-ethanol (C3EO1)]. These solvosurfactants are short amphiphiles that do not form well-defined structures in water such as micelles. For all additives an exponential increase in the solubilizations of the two studied hydrophobic dyes was observed when their concentrations in water were increased. Except for the SDS solution, no difference in the overall shapes of the solubilization curves (dye solubility against additive concentration) was found. All the studied molecules were classified according to their hydrotropic efficiencies, i.e., their abilities to solubilize a hydrophobic, sparingly soluble compound in water. The volume of the hydrophobic parts of the studied additives, roughly evaluated by simple calculations, was found to influence strongly the hydrotropic efficiency; i.e. the larger the hydrophobic part of the additive, the better the hydrotropic efficiency. By contrast, the hydrophilic part carrying a charge or not is of minor importance. Taking the hydrophobic part of the molecules as the key parameter, the water solubilization efficiency of cosolvents, hydrotropes, and solvosurfactants can be described in a coherent way.

Journal Article↗
PubMed2005

Hofmeister effects in surface tension of aqueous electrolyte solution.

The surface tension of electrolyte solutions shows marked specific ion effects. We here show an important role for both ionic solvation energies and ionic dispersion potentials in determining this ion specific surface tension of salt solutions. The ion self-free energy changes when an ion moves from bulk solution into the interfacial region, with its decreasing water density profile. We will show that the solvation energies of different ions correlate very well with the surface tension of salt solutions. Inclusion of this distance-dependent self-free energy contribution brings qualitative agreement with experiments and the right Hofmeister series. This is so not only for surface tension changes but also for measured surface potentials. The inclusion of ionic dispersion interaction potentials further improves the agreement with experiments. We discuss how further progress in the theory of the surface tension of salts can be achieved.

Journal Article↗
PubMed2004

Adsorption and desorption of polymer/surfactant mixtures at solid-liquid interfaces: substitution experiments.

The adsorption of mixtures of aqueous solutions of cationic hydroxyethylcellulose polymer JR400 and anionic surfactant, sodium dodecyl sulfate, using atomic force microscopy (AFM) has been studied. Samples with various compositions from different regions of the ternary phase diagram presented in our previous work were imaged by atomic force microscopy on freshly cleaved mica, and hydrophobically modified mica and silica in soft-contact mode. A series of "washing" (subsequent injection of compositions with gradually decreasing polymer/surfactant ratio) and "scratching" (mechanical agitation of the surface material with an AFM tip) experiments were performed. It was revealed that the morphology of the adsorbed layer altered in a manner following the changes in morphology in the bulk solution. These changes were evidenced in cluster formation in the layer. The results suggest that the influence of the surface was limited to the formation of the adsorbed layer where the local concentrations of polymer and surfactant were higher than those in the bulk. All further modifications were driven by changes in the mixture composition in bulk. Force measurements upon retraction reveal the formation of network structures within the surface aggregates that will greatly slow structural reequilibration.

Adsorption↗
PubMed2004

Adsorption pattern of mixtures of trimethylammonium-modified hydroxyethylcellulose and sodium dodecyl sulfate at solid-liquid interfaces.

We studied mixtures of aqueous solutions of cationic hydroxyethylcellulose JR400 polymer and anionic sodium dodecyl sulfate using dynamic light scattering and atomic force microscopy (AFM). A ternary phase diagram was established showing three interesting realms of the polymer-surfactant-water mixture: a preprecipitation area of lowered viscosity (polymer excess) compared to the pure polymer solution, a postprecipitation area (resolubilization at surfactant excess), and highly diluted samples with a stoichiometrical surfactant-polymer ratio close to that of maximum precipitation. Samples with various compositions representing these areas were imaged by atomic force microscopy on mica and on hydrophobically modified silica in contact mode. A correlation between light scattering data concerning particle size and, more important, structuring in the bulk on one hand and AFM images on the other hand was observed. It was revealed that the influence of surface properties is of less importance for adsorption, compared to the influence of the mixture in the bulk, provided that the mixture is prepared prior to adsorption.

Journal Article↗
PubMed2003

P19: a female and tissue specifically expressed gene in Schistosoma mansoni, regulated by pairing with the male.

A female-specific sequence was isolated from a cDNA library of Schistosoma mansoni and further characterized. Expression of the corresponding gene (p19) depends on pairing with a male. In situ hybridization and immunohistology experiments revealed exclusive expression of the gene in the cells of the vitellarium, suggesting a function in egg formation. In addition, experimental evidence for cross-linking of the protein under oxidative conditions supports the assumption that the p19 gene may code for an egg-shell precursor protein.

Amino Acid Sequence↗
PubMed2001

Adult Gaucher disease in association with primary malignant bone tumors.

BACKGROUND: Malignant neoplastic disorders are more common in patients with Gaucher disease (GD) than in the general population. Very few cases of primary malignant bone tumors in association with GD have been reported to date. Thus, the recommendations for an adequate therapy are often based on limited professional experience. To their knowledge, the authors report the first case of a leiomyosarcoma of the bone in a patient with GD and report another patient with GD and an anaplastic large cell non-Hodgkin lymphoma with localized osseous manifestation. A review of the literature is included. METHODS: The clinical, radiologic, and histologic data of the authors' two patients who had GD and primary malignant bone tumor are presented. Epidemiologic data, clinical data, and treatment results from published reports of 18 patients who had GD and various malignancies and the authors' 2 patients were compared and evaluated. RESULTS: Radiographic examination showed a destructive osteolytic lesion in a case of a leiomyosarcoma of the bone and in a case of anaplastic, large-cell, non-Hodgkin lymphoma. In both cases, the bone marrow architecture was partially effaced by sheets of large histiocytic cells with striated or fibrillary cytoplasm. In both patients, chemotherapy was performed. Whereas the patient who had the leiomyosarcoma showed poor recovery of the bone marrow that necessitated withdrawal of aggressive chemotherapy, the patient who had non-Hodgkin lymphoma and enzyme therapy tolerated the chemotherapy well. In spite of local control after preoperative radiotherapy and hemipelvectomy, the first patient developed lung metastases and finally died. The second patient was continuously free of disease at a follow-up examination 32 months after chemotherapy and radiotherapy. In a total of 20 patients who had malignant disorders and GD, the numbers of males and females were equivalent, and the mean age was 55 years. Approximately 33% presented with a cancer originating in the bone. In 16 patients, follow-up data were available. Of these, after a mean follow-up of 36 months (range, few days-108 mos), only 2 patients were continuously free of disease, and one patient was alive with disease. The other patients had died of disease or hemorrhagic complications of GD. CONCLUSIONS: Because there is a relatively high incidence of malignant disorders of the bone, the study suggested that malignant disorders have to be included in the differential diagnosis of painful lytic lesions in patients who have GD. Evaluation of the expense and value of enzyme therapy to patients who have GD should be undertaken with regard to the incidence of malignant disorders and patient survival.

Adult↗
PubMed2001

Schistosome male-female interaction: induction of germ-cell differentiation.

Male and female schistosomes are permanently paired while they live in the bloodstream of their vertebrate hosts. Female schistosomes produce eggs only when they are in intimate association with a male. Here, I combine classical cytological knowledge about the cellular processes in the female that are affected by the male with recent molecular results that are beginning to allow speculation about the signalling events involved.

Animals↗
PubMed2001

Identification, isolation and characterization of a Fyn-like tyrosine kinase from Schistosoma mansoni.

Growth and development of adult schistosomes requires permanent communication processes of the parasites with their specific host environment and, additionally, between the two genders. Accumulating evidence suggests that, at the molecular level, the mandatory interactions are mediated by signal transduction processes. During recent years, a considerable interest has emerged in the identification of signalling molecules from this parasite and to elucidate their roles during development. In this organism, a number of different molecules have been identified which belong to diverse classes of evolutionary conserved signal transduction cascades. However, up to now no representative of the conserved family of cellular tyrosine kinases has been identified. In this study we present a suitable approach to identify this class of molecules and demonstrate the successful cloning and molecular characterization of one of the isolated genes, the tyrosine kinase 5 (TK5). An unexpected finding was that in the Liberian strain of Schistosoma mansoni the TK5 gene exhibits an allelic polymorphism.

Alleles↗
PubMed2001

Expression and immunolocalization of the 14-3-3 protein of Schistosoma mansoni.

The 14-3-3 protein is a key player in signal transduction processes in various species. We have previously cloned and expressed the 14-3-3 of Schistosoma mansoni. Using the purified protein we have now raised antibodies against it. A highly specific, affinity-purified antibody preparation was employed for the localization of the 14-3-3 protein in the parasite, by both immunohistochemistry and immunoelectron microscopy. The results demonstrate wide distribution of this protein. It was observed in the female excretory system, the nephridia as well as in the genital systems of both sexes, namely in the vitelline gland of female and in the testis of the male. It is also present in the parenchyma and muscle of both male and female worms. Immunoelectron microscopy demonstrated the presence of immunogold-labelled protein in the tegument, subtegument, muscle, parenchyma and in the female reproductive system, in both the cytoplasm and nucleus of vitelline cells, and oocytes. The possible role of the 14-3-3 protein in the genital organs is discussed.

14-3-3 Proteins↗
PubMed2000

Mitochondrial potassium and chloride channels.

Channels selective for potassium or chloride ions are present in inner mitochondrial membranes. They probably play an important role in mitochondrial events such as the formation of delta pH and regulation of mitochondrial volume changes. Mitochondrial potassium and chloride channels could also be the targets for pharmacologically active compounds such as potassium channel openers and antidiabetic sulfonylureas. This review describes the properties, pharmacology, and current observations concerning the functional role of mitochondrial potassium and chloride channels.

Adenosine Triphosphate↗
PubMed1999

Symptomatic bucket handle tear of the lateral meniscus after knee arthroplasty.

We report on a 67-year-old women who had pain after a knee arthroplasty in the region of the lateral meniscus. The arthroscopy showed the remainder of the posterior horn of the lateral meniscus, which luxated as a bucket handle tear into the joint. The resection led to an immediate relief. This case show the importance of meticulous removal of the entire menisci during bicondylar surface replacement.

Aged↗
PubMed1998

Schistosoma mansoni: the varying occurrence of repetitive elements in different strains shows sex-specific polymorphisms.

The repetitive elements W1, W2, and D9 were shown before to be female specific in the Puerto Rican strain of Schistosoma mansoni. In the Liberian strain, however, W1 was detected in both sexes. Therefore, a strain- and sex-specific analysis of the presence of all three repetitive elements has been performed in different schistosome strains. For this analysis, W2 has been isolated and characterized, whereas W1 and D9 were already available. We demonstrate the presence of the W2 element in both sexes in the Liberian strain, which coincides with W1. Furthermore, it is shown that elements W1 and W2, but not D9, can be found in both sexes of the majority of the other strains investigated. We even found an isolate of the Puerto Rican strain with W1 and W2 elements in females and males. This finding contradicts results reported in the literature that demonstrated that W1 and W2 are female specific for the Puerto Rican strain. The data of this study indicate sex-specific polymorphisms, probably associated with the sex chromosomes in schistosomes.

Animals↗
PubMed1998

A female-specific cDNA sequence of Schistosoma mansoni encoding an amidase that is expressed in the gastrodermis.

A female-specifically expressed cDNA clone was obtained by screening of a subtractive cDNA library enriched for RNA from Schistosoma mansoni females. The deduced protein shows significant homology to a class of enzymes functioning as amidases. Northern blots revealed a transcript of 4.0 kb which is absent in larval stages, but is expressed in adult female worms. By in situ hybridization, the expression site of the gene was exclusively localized in the gastrodermis of female schistosomes. This is the first report of a female-specifically transcribed sequence of S. mansoni that is not expressed in the reproductive organs.

Animals↗
PubMed1997

Schistosoma mansoni: gene structure and localization of a homologue to cysteine protease ER 60.

We have isolated and characterized a cDNA encoding the complete sequence of a homologue of the ER luminal cysteine protease ER 60 in Schistosoma mansoni. The deduced protein of 484 amino acids contains two thioredoxin domains, each with the CGHC motif, that characterize all members of the protein disulfide isomerase family. The corresponding gene exists as a single copy and consists of six exons, interrupted by five very small introns of 32 to 40 nucleotides. Immunohistology and in situ hybridization identify the sustentacular cells of the testes, the wall cells of the protonephridia, and the gastrodermis of the gut to be the major tissues of ER 60 gene expression.

Amino Acid Sequence↗