Biomedical subjects

T Klonisch

Publications and source records attributed to T Klonisch.

41 records · Page 3Linked to original sources

PubMed1991

The sheaths of Brugia microfilariae: isolation and composition.

Burgia malayi and B. pahangi microfilariae were isolated from the blood of infected Mastomys natalensis, and were exsheathed by freezing, thawing and agitation. Pure sheaths were obtained by a filtration procedure. The sheaths were found to contain about 95 mol% of amino acids, with proline, glutamic acid/glutamine, alanine, cysteine/cystine and glycine being the major components, and 5 mol% of carbohydrates, notably (N-acetyl)galactosamine, but no (N-acetyl)glucosamine.

Amino Acids↗

PubMed1991

Stimulation of monokine production by lipoteichoic acids.

Lipoteichoic acids (LTAs) isolated from bacterial species, including Staphylococcus aureus, Streptococcus pyogenes A, Enterococcus faecalis, Streptococcus pneumoniae, and Listeria monocytogenes, were tested for their ability to stimulate the production of interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha in cultured human monocytes. LTAs from S. aureus and S. pneumoniae failed to induce monokine production when applied in the concentration range of 0.05 to 5.0 micrograms/ml. However, LTAs from several enterococcal species (0.5 to 5 micrograms/ml) induced the release of all three monokines at levels similar to those observed after lipopolysaccharide stimulation. The kinetics of IL-1 beta and tumor necrosis factor alpha release elicited by LTAs closely resembled those observed following lipopolysaccharide application. Cytokine production occurred in the presence of both fetal calf serum and autologous human serum. Hence, it was not dependent on complement activation and could not be suppressed by naturally occurring human antibodies. Deacylation caused the total loss of monocyte stimulatory capacity. Deacylated LTAs were unable to prevent monocyte activation by intact LTAs, so primary binding of these molecules probably does not involve a simple interaction of a membrane receptor with the hydrophilic portion of the molecule. The results identify some species of LTAs as inducers of monokine production in human monocytes.

Acylation↗

PubMed1987

Isolation of pure sheaths of Litomosoides carinii microfilariae.

A method is described for the isolation of pure, chemically intact sheaths of blood microfilariae of Litomosoides carinii. Microfilariae were isolated according to standard techniques. Exsheathment was performed by freezing-thawing-shaking procedures, repeated 5-10 times, i.e., larvae were frozen in liquid nitrogen, thawed at room temperature, and shaken vigorously for 5 s. Exsheathment rates were about 50%. Sheaths were separated from ensheathed and exsheathed microfilariae and microfilariae fragments by filtration through a polycarbonate filter (2 micron pore size). The achievable yield (about 15% of the sheaths of a batch of microfilariae) was approximately 1 microgram of sheaths per 10(6) microfilariae.

Animals↗

PubMedDate not supplied

Placental localization of relaxin in the pregnant mare.

In situ hybridization employing a cRNA probe derived from a 428-bp fragment of equine relaxin was used to localize relaxin mRNA, and immunocytochemistry was used to localize relaxin itself, in tissues of the placenta-endometrium interface recovered between 33 and 153 days of gestation from mares carrying intraspecific horse, interspecific mule and extraspecific donkey conceptuses. Immunocytochemical staining was also used to localize trophoblast-specific and class I major histocompatibility complex (MHC) antigens on some specimens. Relaxin mRNA and relaxin were both present in the single-cell non-invasive trophoblast layer of the allantochorion between 45 and 153 days of gestation in all three types of equine pregnancy examined. Both, however, were absent from the invasive trophoblast cells of the progenitor chorionic girdle and the differentiated trophoblast cells of the endometrial cups throughout the latters' 60-80-day period of development and regression. Discrete and irregularly spaced clusters of elongated pseudostratified trophoblast cells on the allantochorion remained negative for relaxin mRNA and ligand, but stained strongly for equine trophoblast-specific antigens. These areolae-like structures of the mature horse placenta overlie the mouths of endometrial glands between adjacent microcotyledons and they are clearly involved with the uptake of uterine milk for fetal sustenance. It is speculated that their loose attachment to the endometrium and weak expression of class 1 MHC antigens may serve to tolerize the mother to the paternally-inherited histocompatibility antigens of the fetus.

Animals↗

PubMedDate not supplied

Round spermatids show normal testis-specific H1t but reduced cAMP-responsive element modulator and transition protein 1 expression in men with round-spermatid maturation arrest.

During spermiogenesis, histones are replaced by transition proteins, which in turn are replaced by protamines. The TNP1 gene-encoding TP1 (transition protein 1) protein contains a cAMP-responsive element (CRE) that serves as binding site for the CRE modulator (CREM). To gain further insight into the complex regulation of nucleoprotein exchanges in haploid spermatids and its potential role for spermatogenic impairment, we studied the gene expression of testis-specific histone H1t, CREM, and TNP1 in testicular biopsies from men with normal spermatogenesis (n = 20) and with round spermatid maturation arrest (n = 16). During normal spermatogenesis, H1t messenger RNA (mRNA) was present in 86.2%+/-8.7% of pachytene spermatocytes (stages III-V), whereas H1t protein was synthesized in 83.5%+/-13.0% of pachytene spermatocytes (stages III-V) and persisted in 95.2%+/-3.1% of spermatids (steps 1-5). CREM mRNA was detectable in 74.2%+/-9.4% of pachytene spermatocytes (stages IV-V) and in 78.7%+/-10.0% of spermatids (steps 1-3). CREM protein was synthesized in 81.2%+/-14.2% of spermatids (steps 1-3). TNP1 mRNA was present in 80.0%+/-13.5% of spermatids (steps 2-4), whereas TP1 protein was synthesized in 89.7%+/-5.3% of spermatids (steps 3-4). In men with round spermatid maturation arrest, spermatids only develop to step 3 of differentiation. These spermatids were devoid of both CREM and TP1 but did contain H1t. These results indicate that TP1 is likely to be an important parameter in the histone-to-protamine exchange and in the initiation of spermatid elongation. CREM is involved in the regulation of TNP1 gene expression and consequently plays a vital role in the correct differentiation step from round spermatids to mature spermatozoa.

Chromosomal Proteins, Non-Histone↗