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C Kruse

Publications and source records attributed to C Kruse.

At least 37 records · Page 2Linked to original sources
PubMed1996

Vigilin contains a functional nuclear localisation sequence and is present in both the cytoplasm and the nucleus.

Vigilin is a member of the KH protein family and contains 14 tandemly arranged potential RNA-binding domains. Between KH domains 2 and 3 we have identified a nuclear localization sequence by cloning this sequence into the NH2-terminal region of phage T7 RNA polymerase as a reporter protein and by showing its transfer into the nucleus. Furthermore we provide experimental evidence that Vigilin is present both in the nucleus and in the cytoplasm in similar concentrations. These observations support the notion that Vigilin may shuttle between nucleus and cytoplasm presumably in contact with RNA molecules.

Amino Acid Sequence↗
PubMed1996

Immunocytochemical localization of vigilin, a tRNA-binding protein, after cell fractionation and within the exocrine pancreatic cell of the rat.

A polyclonal antibody against a fusion protein composed of two vigilin domains and gamma-galactosidase was used to localize the tRNA-binding protein vigilin at the ultrastructural level. Immunoreactivity for vigilin was found on membranes bearing ribosomes within the microsome fraction derived from rat livers and on the rough endoplasmic reticulum in rat exocrine pancreatic cells, synthesis corroborating the involvement of vigilin in protein synthesis. Gold labeling was also found in the nucleus and in the microsome fraction in an osmiophilic substance resembling heterochromatin. Both of these localizations, the rough endoplasmic reticulum and the nucleus, are in line with the observation that a vigilin-containing ribonucleoprotein complex binds tRNA.

Animals↗
PubMed1996

Expression of vigilin in the uterus of ovariectomized steroid-treated rats and during the estrous cycle.

The expression of vigilin in the uterus of rats was investigated by immunoblotting and immunohistochemistry and compared to the ultrastructural features of the endometrial cells. Vigilin could not be detected in the uteri of ovariectomized rats. Administration of estrogen, alone or in combination with progesterone, significantly stimulated the expression of vigilin, mainly in the luminal and glandular epithelial cells. Ultrastructurally, these cells show the morphological features of an increased protein synthesis. Untreated mature rats demonstrate a cyclic pattern of vigilin expression with high levels during the estrogen-dominated proestrus and early estrus stages and low levels at metestrus. The down-regulation of vigilin starts with the occurrence of apoptosis and autophagocytosis in the epithelium, but precedes the vanishing of the secretory granules. At diestrus the vigilin expression is intermediate and the vigilin staining of the epithelial cells is reduced. However, the endometrial fibroblasts show a faint staining. Morphologically, these fibroblasts are characterized by large euchromatic nuclei and dilated cisternae of the rough endoplasmic reticulum. The results suggest that in the uterus of rats the expression of vigilin is stimulated by estrogen. Under the experimental conditions chosen no influence of progesterone on vigilin expression was detected.

Animals↗
PubMed1996

CD4-mediated and CD8-mediated cytotoxic and proliferative immune responses to Toxoplasma gondii in seropositive humans.

Both CD4+ and CD8+ cytotoxic T lymphocytes (CTL) are part of the human immune response to Toxoplasma gondii infection. To further our understanding of Toxoplasma immunity, we investigated factors influencing stimulation of CD4+ or CD8+ human T. gondii-specific immune cells. Both antigen-pulsed and Toxoplasma-infected antigen-presenting cells (APC) induced cell proliferation. Toxoplasma-infected APC elicited strong proliferation of CD4+ cells, but little or no proliferation of CD8+ cells, unless high antigen loads were used. Toxoplasma-infected APC stimulated specific cytotoxicity poorly or not at all, owing to death of stimulated cultures, whereas antigen-pulsed APC strongly elicited specific cytotoxicity. Cytotoxicity elicited by either type of APC resided exclusively in CD4+ T cells in polyclonal cultures. Thus, Toxoplasma-infected APC elicited stronger CD4-mediated than CD8-mediated cell proliferation and generated CD4+ CTL more readily than CD8+ CTL. Nonetheless, specific CD8+ memory cells were demonstrated, and rare CD8+ Toxoplasma-specific CTL were subcloned. Fixed Toxoplasma-infected APC (which induce CD8+ CTL) also elicited cell proliferation, but polyclonal cultures stimulated with these infected APC did not die. Unfixed Toxoplasma-infected APC strongly inhibited phytohemagglutinin-induced cell proliferation, whereas fixed APC did not. These data suggested that infected APC were inhibitory or lethal to some immune cells. Further investigations into interactions between immune cells and Toxoplasma-infected cells likely will help elucidate factors involved in the immunopathogenesis of Toxoplasma infection. As other intracellular parasites, including Plasmodium spp. and Leishmania spp., also elicit CD4+ CTL, such work may help establish paradigms governing immunity to intracellular parasites.

Animals↗
PubMed1994

Perioperative plasma erythropoietin levels in hip arthroplasty.

To examine the influence of intra- and postoperative blood loss and operative trauma on erythropoietin (EPO) production we studied patients undergoing endoprosthetic surgery of the hip. Immunoreactive plasma EPO was determined in ten patients (seven male, three female, aged 39-68 years), undergoing surgery for hip arthroplasty (n = 8) or revision hip arthroplasty (n = 2). EPO levels had already been determined during preoperative autologous deposit, thus allowing direct comparison between EPO response to blood loss alone and the response to blood loss and operative trauma. Perioperative blood loss amounted to 1720 (480-8100) ml (median, range). The hemoglobin concentration decreased from 12.4 (10.6-14.0) g/dl (median, range) before the operation to 10.0 (9.3-12.3) g/dl 2 h after the operation. Thereafter, the hemoglobin concentration increased slowly due to transfusion and erythropoiesis and was not significantly different (p < 0.05) from the preoperative value on the seventh postoperative day. The EPO concentration was preoperatively 26 (11-28) mU/ml and increased 2 h after the end of the operation, reaching a peak of 64 (45-104) mU/ml at 24 h. This peak was followed by a plateau at lower, but still elevated levels. The EPO concentration remained significantly elevated above the preoperative value on the seventh postoperative day. Plasma EPO concentrations showed an adequate response to postoperative anemia compared with the time course after autologous donation. In the early postoperative phase, they do not seem to be appreciably influenced by the neuroendocrine response to trauma, by mediators of inflammation, or by the postoperative catabolic state. The slightly elevated EPO concentration in the late postoperative phase indicates that factors other than anemia may contribute to EPO production at this time.

Adult↗
PubMed1992

Specific and sensitive measurement of FK506 and its metabolites in blood and urine of liver-graft recipients.

A specific and sensitive assay for quantifying the immunosuppressant FK506 and its metabolites in blood and urine was developed. 32-O-Acetyl FK506 was synthesized and used as internal standard. FK506 and its metabolites were purified from the samples by solid-liquid extraction and were injected into a high-performance liquid chromatographic (HPLC) system linked to a mass spectrometer (MS) by particle-beam interface. The FK506 derivatives were separated from interfering material by use of a 100 x 4 mm C8 analytical column and water/acetonitrile or water/methanol gradient elution; they were detected by negative chemical ionization with methane as reagent gas. The limit of detection was 25 pg in a standard solution, and the limit of quantification in blood was 250 pg (extracted from 1 mL of blood). The CV was 11.3% at 5 ng, and no interferences with other drugs were found.

Chromatography, High Pressure Liquid↗
PubMed1989

A truncated v-abl-derived tyrosine-specific tyrosine kinase expressed in Escherichia coli.

Several biochemical properties of a 43 kDa v-abl-encoded tyrosine-specific protein kinase (p43v-abl) expressed in Escherichia coli were examined. p43v-abl is a fragment of a 60 kDa v-abl-encoded precursor, p60v-abl, and could be generated by limited proteolysis of a purified p60v-abl with trypsin. Tryptic cleavage of p60v-abl was prevented in the presence of ATP. These results suggest that the catalytic kinase domain of v-abl-derived protein can be separated from other (regulatory) domains by limited proteolysis. p43v-abl readily phosphorylated tyrosine residues on several different protein and peptide substrates, including peptides containing only two amino acid residues. However, the local sequence of the tyrosine-containing peptide substrate significantly affected its rate of phosphorylation. Thus the primary structure and local conformation at the tyrosine acceptor site can play an important role in determining the substrate specificity of v-abl-derived kinase. Phosphorylation by p43v-abl requires Mn2+, Co2+ or Mg2+ and exhibits a strong preference for ATP as phosphate donor. Analogues of ATP and the thiol-reactive reagent N-ethylmaleimide inhibited p43v-abl kinase activity. Purified p43v-abl is intrinsically thermolabile (t1/2 = 5 min at 40 degrees C) and phosphorylates glycerol inefficiently (Km = 1.4 M).

Abelson murine leukemia virus↗
PubMed1987

[The problem of double abnormalities].

Twin monsters are rare obstetrical events. The article reports on the course and the termination of pregnancy of a fetus with epignathus (non separated asymmetrical twin monster) and a fetus with thoracopagus (non separated symmetrical twin monster). In this connection the importance of an early prenatal diagnosis is discussed.

Abnormalities, Multiple↗
PubMed1987

[Bilateral and familial occurrence of germ cell tumors of the testis].

A reclassification study based on the W.H.O. nomenclature was made of 255 testicular germ cell tumours examined in the Department of Pathology of the District Hospital Schwerin between 1958 and 1985. Thereby some cases of bilateral and familial occurrence were found. 4 cases (1.6%) with bilateral tumours were observed. Only in one of the four cases both tumours were discovered at the same time. The longest interval before contralateral occurrence was 19 years. Familial connections were found in 6 cases (2.4%), in one twin-pair and twice in brothers.

Adolescent↗
PubMed1987

[Amyloid tumor of bone].

An osseous plasmocytoma was masked by an excessive tumor-like deposit of amyloid to such an extent that the primary disease was only diagnosed after histological examination of autopsy material from a 62 year old woman. The 20 cm in diameter tumor originated from the manubrium sterni. Other tumors were found in the ribs, right clavicle, thoracic and lumbal spine and in the left femur. A massive layer of amyloid was found in these tumors by microscopy. Plasma cells infiltrated the area between the amyloid plaques and the macroscopically tumor-free vertebral bodies. All other organs were free from amyloid.

Amyloidosis↗
PubMed1985

Phosphorylation of the yeast equivalent of ribosomal protein S6 is not essential for growth.

The yeast equivalent of ribosomal protein S6, known as S10, can be modified by the addition of two phosphates. The two adjacent serines that are likely to be subject to phosphorylation were deduced by comparison with the known sites of phosphorylation on rat liver S6. Using oligonucleotide mutagenesis, we altered the gene for S10 to replace these two serines with alanines. This mutant gene was introduced into a diploid yeast cell heterozygous for each of the two S10 genes. After sporulation, we obtained colonies in which the mutant gene was the only intact S10 gene. Although the ribosomes of these cells contained a full complement of S10, no phosphorylation of S10 was detected. These cells grow exponentially with a doubling time about 50% greater than that of control cells. We conclude that the phosphorylation of S10 is not essential for growth. However, the mutant gene in such cells is very unstable, frequently reverting to wild type, presumably by interaction with the disrupted host genes. We suggest that at some stage of the growth cycle there is strong selection for S10 that can be phosphorylated.

Fungal Proteins↗
PubMed1984

[Histological classification and biological behavior of germ cell tumors of the testis. Studies based on surgery and autopsy data 1958-1979].

Report about 155 cases of germ cell tumors observed at the department of pathology of the district hospital Schwerin, GDR, from 1958 to 1979 in orchiectomy specimens (146 cases) and in autopsies (9 cases; primary diagnosis at autopsy). The reclassification of the tumors according to WHO-Classification resulted in orchiectomy specimens 54 seminomas (37%), 18 embryonal carcinomas (12%), 44 teratocarcinomas (30%), 10 choriocarcinomas with another histological type (7%), 6 teratocarcinomas with seminoma and 5 embryonal carcinomas with seminoma. Yolk sac tumors were found four times, immature teratomas four times, a mature teratoma once. The 9 germ cell tumors in autopsies were seminomas (2), embryonal carcinomas (3), choriocarcinomas (2) and Choriocarcinomas with embryonal carcinoma (2). The average age of patients with seminomas is about 38 years, the average age of the patients with other germ cell tumors is about 28 years. 11 times a maldescended testis was found (10 times of the involved testis, once of the opposite one). Five years after diagnosis two thirds of patients with seminomas and only one third of patients with the other germ cell tumors are alive. Beside the histological type the extension of the tumor at beginning of the therapy is an essential factor of prognosis.

Adult↗
PubMed1983

Malate synthase: aggregation, deaggregation, and binding of phospholipids.

Octameric malate synthase is located in the glyoxysomes of cucumber cotyledons. The enzyme is predominantly confined to the organelle's membrane and can be solubilized with Mg2+. Separation of cell structures in a zonal rotor afforded, besides glyoxysomes, two other zones with malate synthase activity, viz., in the gradient supernatant and in the range of the endoplasmic reticulum (ER). Malate synthases of these three fractions were purified to apparent homogeneity and classified according to their molecular weight. Differences in subunit molecular weight, however, could not be detected when malate synthases from the three fractions were compared. Mature malate synthase, as well as malate synthase prepared from fractions sedimenting similarly to the ER, exhibited the following behavior with respect to aggregation and deaggregation: at low salt concentrations and in the absence of Mg2+, the enzyme shifted to aggregated forms (approx 100 S); with 2 mM Mg2+, malate synthase deaggregated and occurred predominantly as an octamer (19 S). By changing buffer conditions, mature forms of malate synthase could be interconverted repeatedly between octameric and aggregated forms, whereas a monomeric form (5 S), prepared from soluble fractions assigned to the cytosol, did not oligomerize. The amphipathic properties of malate synthase were demonstrated by the enzyme's capacity for binding phospholipids.

Macromolecular Substances↗
PubMed1983

Oligomerization of malate synthase during glyoxysome biosynthesis.

The octameric malate synthase, found in glyoxysomes of plants, is synthesized as monomeric precursor in the cytoplasm. The precursor form does not possess a different subunit molecular weight than the mature organellar enzyme, but differs from the organellar protein by not oligomerizing and aggregating. This was shown by synthesis in a cell-free reticulocyte lysate system programmed with cucumber poly A+-mRNA followed by immunoprecipitation of the radiolabeled translation products. The precursor form of malate synthase was also detected in vivo in the cytosol of pulse-labeled cucumber cotyledons after immunoprecipitation of the radiolabeled polypeptide. At low salt concentrations, mature malate synthase can be converted into aggregated forms. However, the precursor form obtained either by in vitro translation or by extraction from the cytosol after short pulses of radioactive methionine, could neither be oligomerized into the octameric form nor aggregated into the 100-S form. Processing of malate synthase, assumed to be a requisite for oligomerization, took place rapidly in the glyoxysomes, but proceeded only slowly in the cytosol. This was demonstrated both by the uptake of in vitro-translated malate synthase into glyoxysomes, and by analysis of newly synthesized malate synthase detectable in glyoxysomes in vivo. In both cases the octamer was by far the predominant form.

Cell Compartmentation↗