Granulocyte colony-stimulating factor receptor mutations in a patient with acute lymphoblastic leukemia secondary to severe congenital neutropenia.
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Adolescent↗
Biomedical subjects
H Schulze
Publications and source records attributed to H Schulze.
c-mpl mutations are the cause of congenital amegakaryocytic thrombocytopenia.
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare disease presenting with isolated thrombocytopenia in infancy and developing into a pancytopenia in later childhood. Thrombopoietin (TPO) is the main regulator of thrombocytopoiesis and has also been demonstrated to be an important factor in early hematopoiesis. We analyzed 9 patients with CAMT for defects in TPO production and reactivity. We found high levels of TPO in the sera of all patients. However, platelets and hematopoietic progenitor cells of patients with CAMT did not show any reactivity to TPO, as measured by testing TPO-synergism to adenosine diphosphate in platelet activation or by megakaryocyte colony assays. Flow cytometric analysis revealed absent surface expression of the TPO receptor c-Mpl in 3 of 3 patients. Sequence analysis of the c-mpl gene revealed point mutations in 8 of 8 patients: We found frameshift or nonsense mutations that are predicted to result in a complete loss of c-Mpl function in 5 patients. Heterozygous or homozygous missense mutations predicted to lead to amino acid exchanges in the extracellular domain of the receptor were found in 3 other patients. The type of mutations correlated with the clinical course of the disease. We propose a defective c-Mpl expression due to c-mpl mutations as the cause for thrombocytopenia and progression into pancytopenia seen in patients with CAMT.
Adenosine Diphosphate↗
Cultures of exfoliated epithelial cells from different locations of the human urinary tract and the renal tubular system.
Exfoliated human urinary tract epithelial cells and renal tubular cells from urinary sediments of healthy adults, of urological patients and of internal patients were isolated and cultured. Cells started proliferating within 1 week after seeding a sediment. Proliferating cells formed colonies of different morphologies, designated as type-1 or type-2 cell colonies. Type-1 cell colonies showed irregular contours and spindle-like cells within the colonies. Subcultivation of type-1 cells for up to six passages was possible. Type-2 cell colonies showed smooth-edged contours and subcultivation was not possible. The epithelial character of type-1 cells was demonstrated by positive immunohistochemical staining for cytokeratin-7. In contrast to carbonic anhydrase-positive stained Madin Darby canine kidney cells (MDCK), which were used as positive controls for renal tubular cells, type-1 cells were carbonic anhydrase-negative on staining with the cobalt phosphate method. This indicates that type-1 cells were not of renal tubular origin. Type-2 cells were positively stained for carbonic anhydrase, indicating that type-2 cells were renal tubular cells. Type-2 cell colonies could be assigned to two subgroups with different cell forms. Colonies of cobblestone-like cells more often occurred than type-2 cell colonies with spindle-like cells, which are described in this study for the first time. Colonies with cobblestone-like cells formed domes (hemicysts), whereas spindle-like type-2 cell colonies did not. Cultures of urinary sediments from healthy adults, elderly multimorbid patients treated with furosemide, and urological patients with urolithiasis treated with sulfamethoxazole/trimethoprim and/or with a percutaneous nephrostomy catheter were compared. In 52% of all cultured sediments from healthy adults, in 30% of those from multimorbid patients, and in 75-80% of those from urological patients cells proliferated to colonies. The ratios of type-1 to type-2 cell colonies were 3.3:1 (healthy adults), 1.4:1 (urological patients with urolithiasis), and 1.8:1 (urological patients with urolithiasis, urine was directly collected from the renal pelvis with a percutaneous nephrostomy catheter). Successful cultures of the urinary sediments from these three groups revealed means of 3 or 4 colonies, 14 colonies, and 21 colonies, respectively. Differences in the number of colonies in relation to sex were observed only for the group of urological patients. It was shown that type-1 cells were urothelial cells, which did not show morphological differences due to their locations of origin within the urinary tract, whereas type-2 cells were probably renal tubular cells. These findings offer new aspects in the culturing of human urothelial or kidney epithelial cells with a method based on noninvasive collecting of specimens and requiring only minimal culture effort. The cultures obtained by this method can be used for in vitro studies in toxicological and clinical research.
Adolescent↗
Thrombopoietin induces the generation of distinct Stat1, Stat3, Stat5a and Stat5b homo- and heterodimeric complexes with different kinetics in human platelets.
OBJECTIVE: Thrombopoietin (TPO) is the pivotal regulator of thrombocytopoiesis and megakaryocytopoiesis, and binding to its receptor c-Mpl leads to activation of at least two different signaling pathways: the Jak-Stat pathway and the Ras-MAPK pathway. Our aim was to elucidate which Stat-complexes are formed in TPO signal transduction in human blood platelets. MATERIALS AND METHODS: We used electrophoretic mobility shift assays (EMSA) in order to analyze the formation of distinct Stat complexes on two distinct oligonucleotide probes. Furthermore, we used immunoprecipitation and Western blotting of protein lysates from TPO-stimulated platelets. RESULTS: We found homodimers of Stat1alpha, Stat3, Stat5a, and Stat5b, as well as heterodimers of Stat1/Stat3 and Stat5a/Stat5b, but no Stat1/Stat5 or Stat3/Stat5 heterodimers are formed in platelets in response to TPO. Stat5 complexes bound to labeled DNA with a fast kinetic followed by Stat3 and Stat1. The adapter protein CrkL is present in DNA-bound Stat5 complexes and predominantly bound to Stat5b. The kinase ERK2 is also tyrosine phosphorylated after TPO-stimulation of platelets but this activation does not modulate the phosphorylation of the serine residues in the PXSP motif present in Stat1 and Stat3. CONCLUSION: Our findings thus emphasize the differential regulation of Stat1, Stat3, Stat5a, and Stat5b in platelets and may be an appropriate model of c-Mpl signaling in mega-karyopoiesis.
Blood Platelets↗
Objective evaluation of the morphology of human epididymal sperm heads.
Spermatozoa were obtained from nine epididymal regions of six epididymides taken from five men undergoing castration for prostatic carcinoma (53-76 years) and from one man with testicular cancer (38 years). Spermatozoa were obtained by mincing tissue in phosphate-buffered saline, making air dried smears and staining with Hemacolor. The percentage of sperm heads categorised subjectively as normal (of uniform shape) or otherwise was calculated for each region. This confirmed that grossly swollen sperm heads (previously shown to be artefacts) were only present in proximal regions of the duct. A computer-aided sperm morphology analyser (Sperm Class Analyzer(R)) was used to provide objective measurements of sperm head area, perimeter, length and width of the uniform sperm heads and revealed that there was a gradual and statistically significant decline in sperm head size upon maturation, as occurs in other species. There was no significant difference between the morphometric parameters of spermatozoa obtained from the distal cauda epididymis and those obtained from the ejaculates of young normozoospermic patients.
Adult↗
Extrusion of wheat or sorghum and/or addition of exogenous enzymes to pig diets influences the large intestinal microbiota but does not prevent development of swine dysentery following experimental challenge.
A study was made of dietary influences on the large intestinal microbiota of pigs and on the incidence of swine dysentery (SD) after experimental infection with Brachyspira hyodysenteriae, the aetiological agent of SD. Animals were fed diets based either on wheat (expts 1 and 2) or sorghum (expt 2). Grains were ground and fed either raw or after high temperature and pressure extrusion and/or after addition of exogenous enzymes to the whole diet to reduce the starch and soluble non-starch polysaccharides available for fermentation in the large intestine. Limiting fermentation creates conditions that apparently reduce the incidence of SD after infection with B. hyodysenteriae. The diets were fed to weaned pigs for 4-6 weeks, then half the animals on each diet were killed and gut samples collected for microbiology. The treatments had little effect on bacterial numbers. In expt 1, dietary extrusion of wheat reduced lactobacilli in the large intestine. Addition of enzymes to extruded wheat-based diets in expt 2 reduced facultative anaerobes and increased non-sporing anaerobes. Addition of enzymes to a raw sorghum diet in expt 3 decreased numbers of facultative anaerobes, while extrusion of sorghum increased total anaerobes. Bacteroides spp. and Fusobacterium spp., which act in synergy with B. hyodysenteriae in SD, were isolated at a higher percentage in pigs fed the untreated wheat diet than in pigs fed the treated wheat diets. Following experimental infection the incidence of SD amongst pigs fed treated wheat diets was slightly lower than those fed the untreated diet, but with sorghum-based diets the opposite was found. Overall, the different dietary treatments used did not significantly reduce SD.
Animals↗
[Results of an evaluation of psychotherapeutic care from the viewpoints of patients and therapists in Saxony-Anhalt].
With the enforcement of the German law for psychotherapeutics at the beginning of 1999, the field of psychotherapy detached from a widespread "delegation procedure" through the possibility of first-access for patients to a psychotherapist. In the form of an experiment, Saxony-Anhalt practiced as the only land in the Feral Republic of Germany a modified form of delegation procedure in the legal health insurance since 1992. The most important modification consisted in the possibility of first-access for the patient to the psychotherapist. Using selected results of the investigation in the view of psychotherapy patients and from medical and psychological psychotherapists, the situation after 5 years since introduction of this model in the out-patient, psychotherapeutic care in Saxony-Anhalt will be shown, as well as experience gained from this model.
Ambulatory Care↗
Induction of unscheduled DNA synthesis in primary human urothelial cells by the mycotoxin ochratoxin A.
Ochratoxin A (OTA) is a widespread contaminant in human staple food. Exposure of humans to this mycotoxin is a matter of concern because OTA is a known rodent carcinogen. As the urothelium is one target tissue of this mycotoxin, primary cultured human urothelial cells (HUC) from adults and children were used to analyze the induction of unscheduled DNA synthesis (UDS) by OTA. HUC were isolated from the ureters or renal pelves of two nephrectomized adults and of two children with ureteropelvic junction stenosis and cultured under serum-free conditions. After a confluency of 70-80% was reached, cell proliferation was suppressed by arginine-deficient medium (ADM), and UDS was assessed autoradiographically by 3H-thymidine incorporation upon exposure to OTA (10-2000 nM), ethyl methanesulfonate (EMS, 5 mM, positive control), or dimethyl sulfoxide (DMSO, 0.2%, solvent control). In control cultures the level of UDS was low. Exposure to EMS resulted in an induction of UDS (2-to 5-fold compared to control), thus allowing the sensitive detection of repair resulting from induction of DNA lesions in all four specimens, and demonstrating that repair of EMS-induced DNA lesions can take place under the chosen culture conditions. In two HUC cultures derived from adults, a significant induction of UDS was observed in the concentration range of 50-500 nM OTA. The highest fraction of cells in repair (CIR) was found at 50 nM OTA for the HUC from the older male (50% CIR). The maximum response in the other specimens from the adult female and the 7-year-old boy were seen at OTA concentrations of 500 and 250 nM, respectively. In contrast to all other specimens, no significant induction of UDS by OTA was found in the HUC cultures derived from an infant's urothelium. Signs of cytotoxicity were observed above 500 nM OTA in all cultures. The varying susceptibility toward OTA observed in vitro may hint at varying predispositions of individuals in vivo.
Adult↗
Risk factors for relapse in stage I non-seminomatous germ-cell tumors: preliminary results of the German Multicenter Trial. German Testicular Cancer Study Group.
Risk factor analysis to identify low-risk patients for occult metastatic disease (vascular invasion, percentage embryonal carcinoma, MIB-I proliferation rate) yields reliable results if performed by experts. A correct prediction is possible at the 90% level. Similar accuracy, however, may be achieved if the computed tomography (CT) staging is optimized and the evaluation performed by an experienced investigator. The combination of both methods (biological risk factor analysis and CT staging) may virtually exclude the risk of relapse in a limited number of patients. However, so far, no risk factor that is able to reliably predict occult metastatic disease or relapse in clinical state I patients has been identified in prospective trials. The preliminary results of the current German Multicenter Trial suggest an inferior value of prediction for low-risk patients if risk factor analysis and/or CT staging is performed in non-specialized centers.
Antineoplastic Combined Chemotherapy Protocols↗
Thrombopoietin acts synergistically on Ca(2+) mobilization in platelets caused by ADP or thrombin receptor agonist peptide.
Thrombopoietin (TPO) is the main regulator of megakaryopoiesis and influences also the function of mature platelets. TPO has been shown to synergize in multiple platelet activation processes induced by various agonists. Our aim was to elucidate whether TPO affects calcium signaling during platelet activation processes. TPO demonstrated a synergistic effect on the exocytosis induced by suboptimal doses of adenosine diphosphate (ADP) and the thrombin receptor agonist peptide (TRAP). We detected synergistic effects of TPO on the ADP or TRAP induced Ca(2+) mobilization in a small range of very low agonist concentrations. The TPO synergism on Ca(2+) mobilization and CD62P expression was measurable in different, nonoverlapping ranges of ADP or TRAP concentrations. Sustaining the agonist-induced calcium signal with thapsigargin led to a detectable TPO synergism in CD62P expression even in agonist concentrations in which the synergism only occurs in Ca(2+) signaling without thapsigargin.
Adenosine Diphosphate↗
Discrimination learning of amplitude modulated tones in Mongolian gerbils.
Discrimination learning of 100% sinusoidal amplitude modulated tones (AM) was investigated in adult Mongolian gerbils using a footshock motivated shuttle box avoidance go/no go paradigm. AM stimuli to be discriminated had identical carrier frequency (2 kHz) but differed in modulation frequency (fm) by one octave. Six groups of gerbils were trained to discriminate AM-pairs with fm ranging from 10 to 640 Hz. Learning proceeded faster and discrimination performance was slightly better for low fm, up to 80 Hz, than for high fm, above 80 Hz. These results may be related to cortical AM encoding (Schulze, H. and Langner, G., J. Comp. Physiol. A, 181 (1997) 651-663), which is temporal for low fm (synchrony code) and spatial for high fm (rate-place code). This may implicate different neuronal learning strategies or distinct behavioral meanings influencing the discrimination training.
Acoustic Stimulation↗
Enhancement of cation diffusion rates across the 410-kilometer discontinuity in Earth's mantle
Rates of cation diffusion (magnesium, iron, and nickel) have been determined in olivine and its high-pressure polymorph, wadsleyite, at 9 to 15 gigapascals and 1100 degrees to 1400 degreesC for compositions that are relevant to Earth's mantle. Diffusion in olivine becomes strongly dependent on composition at high pressure. In wadsleyite, diffusion is one to two orders of magnitude faster than in olivine, depending on temperature. Homogenization of mantle heterogeneities (chemical mixing) and mineral transformations involving a magnesium-iron exchange will therefore occur considerably faster in the transition zone than at depths of less than 410 kilometers.
Journal Article↗
[Occupational risk factors for bladder carcinoma. A case control study].
Aim of this case-control study, performed on 412 male bladder cancer cases and 414 controls with benign prostatic hyperplasia in a former area of coal, iron and steel industries in Germany, was to identify occupations with an increased bladder cancer risk. In bladder cancer cases, smokers were overrepresented (58.3%) compared to controls (35.2%). The percentage of patients who had stopped smoking for at least 10 years did not differ in cases (10.2%) and controls (9.7%). Significantly elevated smoking-adjusted bladder cancer odds ratios (MH) were observed in painters and lacquers (MH 2.24, 95% CI 1.07-5.13), chemistry-related occupations (MH 2.44, 95% CI 1.05-5.67), coke plant workers (MH 2.89, 95% CI 1.16-7.16) and hard coal miners (MH 2.33, 95% CI 1.52-3.58). Significantly decreased smoking-adjusted bladder cancer odds ratios (MH) were observed in businessmen (MH 0.64, 95% CI 0.45-0.92) and office personnel (MH 0.58, 95% CI 0.41-0.81). In these two groups a relevant exposure to occupational bladder carcinogens is not likely.
Aged↗
Serum levels of thrombopoietin, IL-11, and IL-6 in pediatric thrombocytopenias.
We measured serum levels of thrombopoietin (TPO), interleukin (IL)-11, and IL-6 in 90 different samples from 67 pediatric patients with thrombocytopenia (TP). The cytokine levels were determined by enzyme-linked immunosorbent assays (ELISA), and the biological activity of TPO was measured using a cell line transfected with human c-mpl. In patients with impaired megakaryocytopoiesis, as found in diseases such as aplastic anemia, amegakaryocytic TP, or TP with absent radii, we found TPO levels which were highly elevated compared with normal values (mean=261 AU/ml, n=52, vs. 22 AU/ml in healthy controls). In contrast, patients suffering from idiopathic thrombocytopenic purpura (mean=16 AU/ml, n=31) or platelet function defects (mean=23 AU/ml, n=7) demonstrated normal TPO levels. The biological activity tested in the bioassay correlated well with the ELISA data. However, sera of some patients with amegakaryocytic TP demonstrated a remarkably higher biological activity of TPO than expected from the ELISA data. Within the different groups there was no correlation between platelet counts and TPO levels. Only 27% of all samples had elevated levels of IL-11 (mean=450 pg/ml, n=20). Elevated IL-6 serum levels were detected in only 13% of all samples analyzed (mean=42 pg/ml, n=12). We conclude that megakaryocytopoiesis is regulated mainly by TPO, that it is dependent on the platelet and the megakaryocytic mass, and that IL-11 plays an additional role in supporting the platelet production. IL-6 does not appear to be up-regulated in children with thrombocytopenia.
Adolescent↗
Auditory cortical responses to amplitude modulations with spectra above frequency receptive fields: evidence for wide spectral integration.
Auditory neurons typically respond to a restricted range of frequencies and amplitudes of pure tone stimuli. These findings have led to the concept of the classical frequency receptive field. Over the last few years evidence has accumulated that stimuli outside the frequency and amplitude boundaries of a neuron's receptive field can influence responses to stimuli inside the classical receptive field. We could recently show that sinusoidally amplitude-modulated pure tones could excite cortical neurons although all of their spectral components were above the spectral range of pure tones effective to excite the neuron. This result demonstrated that neurons in the auditory cortex integrate over spectral ranges that are much wider than is evident from responses to pure tones. Here, using sinusoidally amplitude-modulated pure tone stimuli we determine electrophysiologically the high-frequency boundaries of the spectral integration capabilities of auditory cortical neurons in anaesthetized Mongolian gerbils under normal conditions and under the influence of the microiontophoretically applied GABAA-receptor antagonist bicuculline. Our results demonstrate that some auditory cortical neurons integrate over the gerbil's entire audible spectrum. Therefore, the classical excitatory frequency receptive field of an auditory cortical neuron, as determined with pure tone stimuli, cannot provide a satisfactory description of its spectral integrative properties.
Acoustic Stimulation↗
Suramin treatment in hormone- and chemotherapy-refractory prostate cancer.
OBJECTIVES: Suramin, a polysulfonated naphtylurea with anti-growth factor activity, was used in the treatment of metastatic, hormone- and chemotherapy-refractory prostate cancer. Recent studies have proved the effect of suramin on prostate cancer. METHODS: Between March 1990 and January 1994, 27 patients with metastatic prostate cancer were enrolled in this study. Treatment regimen consisted of a loading phase, allowing patients to reach suramin serum levels between 180 and 250 microg/mL using a suramin dose of 1.4 g/m2 at 3-day intervals. Constant suramin serum levels were maintained by a 0.5 to 1-g/m2 dose every 7 to 10 days. Because previous studies showed suramin to have serious toxicity, compromised organ status was excluded by repeated examinations. RESULTS: Six patients did not complete the suramin loading phase because of side effects and were removed from the study. With an average cumulative suramin dose of 14.2 g, 33% of the assessable patients (7 of 21) experienced a more than 50% reduction of prostate-specific antigen (PSA) and/or alkaline phosphatase (AP) serum levels. Mean survival in these suramin-responsive patients was 495 days. Two of these patients experienced a remarkable reduction of metastases in bone scan examinations. Another 48% of the patients (10 of 21) had essentially unchanged AP and PSA serum levels during suramin treatment, indicating stable disease. Mean survival of these patients was 341 days. In 4 patients undergoing suramin treatment, continuous clinical progression of the disease was observed (mean survival 79 days). Toxicity was less or comparable to prior reported studies; the most common side effects were polyneuropathy, allergic skin rash, and vortex keratopathy. CONCLUSIONS: Suramin has limited, but significant, efficacy even in chemotherapy- and hormone-refractory prostate cancer, without serious toxicity.
Aged↗
Defective c-Mpl signaling in the syndrome of thrombocytopenia with absent radii.
Thrombocytopenia with absent radii (TAR) syndrome is a rare congenital defect with severe hypomegakaryocytic thrombocytopenia and bilateral radial aplasia. To elucidate a possible relationship between thrombocytopenia in TAR and defects in the thrombopoietin (TPO)/c-Mpl system, we examined TPO activity in sera from six patients and in vitro reactivity of the patients' platelets to recombinant human TPO. We found elevated TPO serum levels in all patients, excluding a TPO production defect as a pathomechanism for the thrombocytopenia. In contrast to healthy controls, however, platelets of TAR patients failed to respond to recombinant TPO as measured by testing TPO synergism to suboptimal concentration of platelet activators. Most interestingly, TPO-induced tyrosine phosphorylation of platelet proteins was completely absent (four out of five) or markedly decreased (one out of five). More detailed investigations of the signal cascades of c-Mpl demonstrated the absence of Jak2 phosphorylation after TPO stimulation in a TAR patient's platelets. A defect in the early events of c-Mpl signal transduction might be the reason for impaired megakaryocytopoiesis in TAR syndrome.
Blood Platelets↗