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M Thiel

Publications and source records attributed to M Thiel.

At least 37 records · Page 2Linked to original sources
PubMed2001

Comparative proteome analysis of Leishmania donovani at different stages of transformation from promastigotes to amastigotes.

To pass through its life cycle, protozoan parasites of the genus Leishmania have to differentiate from promastigotes to amastigotes. The molecular basis underiving this major transformation is poorly understood. One way to study this phenomenon is to isolate and characterize proteins that are specifically expressed in one of the two stages of the life cycle or during the stage differentiation. Using two-dimensional gel electrophoresis, we mapped the Leishmania donovani proteome during stage differentiation to identify stage-specific proteins and regulons. A protocol for extracting proteins of both promastigote and amastigote L. donovani cells was developed, which is compatible with isoelectric focusing. Up to 400 L. donovani protein spots were visualized on a silver-stained gel. Metabolic labeling of the cells was used to compare directly the protein synthesis pattern with the protein level pattern. The silver-stained images of L. donovani cells harvested on different days of stage differentiation were compared to the corresponding autoradiographs. A marked decrease in protein synthesis during stage differentiation from promastigotes to amastigotes was observed. The stained protein pattern as well as the protein pattern on the autoradiograph changed dramatically, especially after day 3 (about 24 h after pH shift) of transformation.

Animals↗
PubMed2001

Antibiotic resistance pattern and visual outcome in experimentally-induced Staphylococcus epidermidis endophthalmitis in a rabbit model.

OBJECTIVE: To study whether the clinical outcome of Staphylococcus epidermidis-induced endophthalmitis in rabbits is related to the antibiotic resistance pattern of the infecting strain. DESIGN: Experimental animal study. PARTICIPANTS: The right eyes of 36 New Zealand white albino rabbits were inoculated with strains of S. epidermidis that displayed various patterns of antibiotic resistance. METHODS: There were 12 rabbits in each of three study groups: fully antibiotic susceptible (FS), partially antibiotic resistant (PR), and multiresistant (MR). Five days after inoculation, the eyes were enucleated and prepared for histologic studies. MAIN OUTCOME MEASURES: Comparisons among the three groups were made based on electroretinographic (ERG) findings, histologic evaluation by a masked observer, and clinical examination. RESULTS: Electroretinographic findings on all rabbits were made by an unmasked observer. At 30 hours after inoculation, the ERG was diminished to 65% of normal for group FS, compared with a flat ERG waveform for groups PR (P < 0.05) and MR (P < 0.05). The ERG waveform was flat for all three groups at 72 hours after inoculation. Histologic evaluation by use of a histologic score revealed that the degree of inflammation and destruction of the retina was less for group FS (n = 10) compared with groups PR (n = 8) and MR (n = 8). Clinical examination revealed that there was a trend of less ocular inflammation for group FS compared with groups PR and MR. CONCLUSIONS: In a rabbit model of S. epidermidis-induced endophthalmitis, antibiotic-susceptible strains caused less inflammation and destruction of the infected retina than did antibiotic-resistant strains.

Animals↗
PubMed2001

Application of shock waves in medicine.

Extracorporeal-generated shock waves were introduced approximately 20 years ago to disintegrate kidney stones. This treatment method substantially changed the treatment of urolithiasis. Shock waves have become the treatment of choice for kidney and ureteral stones. Urology, however, is not the only medical field for the potential use of shock waves for problems. Shock waves subsequently have been used in orthopaedics and traumatology to treat various insertional tendinopathies (enthesiopathies) and delayed unions and nonunions of fracture. Shock wave application also has been used in the treatment of tendinopathies in veterinary conditions (race horses). The concept of orthopaedic disorders is that shock waves stimulate or reactivate healing processes in tendons, surrounding tissue and bones, probably through microdisruption of avascular or minimally vascular tissues to encourage revascularization, release of local growth factors, and the recruitment of appropriate stem cells conducive to more normal tissue healing. The current author will give an overview of history and basic research of the application of shock waves in medicine.

High-Energy Shock Waves↗
PubMed2001

Effects of intravenous fat emulsions on lung function in patients with acute respiratory distress syndrome or sepsis.

OBJECTIVE: To investigate whether rapid or slowly infused intravenous fat emulsions affect the ratio of prostaglandin I2/thromboxane A2 in arterial blood, pulmonary hemodynamics, and gas exchange. DESIGN: Prospective, controlled, randomized, crossover study. SETTING: Operative intensive care unit of a university hospital. PATIENTS: Eighteen critically ill patients. Ten patients were stratified with severe sepsis, and eight patients had acute respiratory distress syndrome (ARDS). INTERVENTIONS: Patients were assigned randomly to receive intravenous fat emulsions (0.4 x resting energy expenditure) over 6 hrs (rapid fat infusion) or 24 hrs (slow fat infusion) along with a routine parenteral nutrition regimen, by using a crossover study design. MEASUREMENTS AND MAIN RESULTS: Systemic and pulmonary hemodynamics as well as gas exchange measurements were recorded via respective indwelling catheters. Arterial thromboxane B2 and 6-keto-prostaglandin-F1alpha plasma concentrations were obtained by radioimmunoassay, and 6-keto-prostaglandin-F1alpha/thromboxane B2 ratios (P/T ratios) were calculated. Data were collected immediately before and 6, 12, 18, and 24 hrs after onset of fat infusion. In the ARDS group, P/T ratio increased by rapid fat infusion. Concomitantly, pulmonary shunt fraction, alveolar-arterial oxygen tension difference [P(a-a)o2]/Pao2, and cardiac index increased as well, whereas pulmonary vascular resistance and Pao2/Fio2 declined. After slow fat infusion, a decreased P/T ratio was revealed. This was accompanied by decreased pulmonary shunt fraction, lowered P(a-a)o2/Pao2, and increased Pao2/Fio2. Correlations between plasma concentrations of 6-keto-prostaglandin-F1alpha or thromboxane B2 and measures of respiratory performance could be shown during rapid and slow fat infusion, respectively. In the sepsis group, the P/T ratio remained unchanged at either infusion rate, but pulmonary shunt fraction and P(a-a)o2/Pao2 decreased after rapid fat infusion, whereas Pao2/Fio2 increased. CONCLUSION: Pulmonary hemodynamics and gas exchange are related to changes of arterial prostanoid levels in ARDS patients, depending on the rate of fat infusion. In ARDS but not in sepsis patients clear of pulmonary organ failure, a changing balance of prostaglandin I2 and thromboxane A2 may modulate gas exchange, presumably via interference with hypoxic pulmonary vasoconstriction.

APACHE↗
PubMed2001

Simulated microgravity, psychic stress, and immune cells in men: observations during 120-day 6 degrees HDT.

Because 6 degrees head-down tilt (HDT) is an established method to mimic low gravity on earth, the aim of the present study was to determine the effects of 120-day HDT on psychic stress and peripheral blood immune cells in six healthy male volunteers. Psychological state was assessed by a current stress test, and cortisol was measured in saliva. During HDT, all volunteers developed psychic stress, and the diurnal rhythm of cortisol secretion was significantly altered. In addition, urine excretion of dopamine and norepinephrine increased. The innate part of the immune response was activated, as evidenced by the increase in the expression of beta(2)-integrins on polymorphonuclear leukocytes and a rise in the number of circulating natural killer (NK) cell lymphocytes. The ratio of T-helper to T-cytotoxic and T-suppressor cells decreased, whereas no changes in T and B lymphocytes were observed. Plasma levels of interleukin-6 increased significantly and returned to basal levels after the end of the HDT period. Thus 6 degrees HDT appears to be a valid model to induce psychic stress and neuroendocrine-related changes in the immune system, changes that might also be encountered by astronauts and cosmonauts during long-duration spaceflights.

Adult↗
PubMed2001

Changes in microvascular fluid filtration capacity during 120 days of 6 degrees head-down tilt.

We used venous congestion strain gauge plethysmography (VCP) to measure the changes in fluid filtration capacity (K(f)), isovolumetric venous pressure (Pv(i)), and blood flow in six volunteers before, on the 118th day (D118) of head-down tilt (HDT), and 2 days after remobilization (Post). We hypothesized that 120 days of HDT cause significant micro- and macrovascular changes. We observed a significant increase in K(f) from 3.6 +/- 0.4 x 10(-3) to 5.7 +/- 0.9 x 10(-3) ml. min(-1). 100 ml(-1). mmHg(-1) (+51.4%; P < 0.003), which returned to pretilt values (4.0 + 0.4 x 10(-3) ml. min(-1). 100 ml(-1). mmHg(-1)) after remobilization. Similarly, Pv(i) increased from 13.4 +/- 2.1 mmHg to 28.9 +/- 2.8 mmHg (+105.8%; P < 0.001) at D118 and was not significantly different at Post (12.4 +/- 2.6 mmHg). Blood flow decreased significantly from 2.3 +/- 0.3 to 1.3 +/- 0.2 ml. min(-1). 100 ml tissue(-1) at D118 and was found elevated to 3.4 +/- 0.7 ml. min(-1). 100 ml tissue(-1) at Post. We believe that the increased K(f) is caused by a higher microvascular water permeability. Because this may result in edema formation, it could contribute to the alterations in fluid homeostasis after exposure to microgravity.

Adult↗
PubMed2001

Immunomodulation in septic shock: hydrocortisone differentially regulates cytokine responses.

Cortisol is known to be an immunomodulatory hormone that exerts suppressive and permissive effects on the immune response. Little is known regarding the evolution of the cytokine response in human septic shock in the presence of hypercortisolemia induced by infusion of stress doses of hydrocortisone. Twenty-four consecutive patients with high-out-put circulatory failure (cardiac index, >4 liters/min per m(2)) who met the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference Committee criteria for septic shock were enrolled in a prospective, double-blind study. The severity of illness at the time of enrollment was graded using the Acute Physiology and Chronic Health Evaluation II system, and the evolution of sepsis-induced organ dysfunction syndrome was assessed using Sepsis-Related Organ Failure Assessment scores. After randomization, hyper-cortisolemia was induced in 12 patients by infusion of 100 mg of hydrocortisone, followed by continuous infusion of 0.18 mg/kg per h. Levels of the circulating cytokines tumor necrosis factor alpha (TNF), interleukin 6 (IL-6), IL-8, and IL-10 were serially measured at prospectively defined time points during the first 5 d after randomization. The infusion of hydrocortisone was associated with significant reductions in serum IL-6 and IL-8 levels and with earlier resolution of the sepsis-induced organ dysfunction syndrome. IL-6 levels started to differ between the groups on day 5. The TNF and IL-10 responses were not altered by hydrocortisone infusion. Hydrocortisone infusion in septic shock differentially regulated the cytokine responses. IL-6 and IL-8 levels decreased significantly and IL-6 levels differed between the groups, whereas TNF and IL-10 levels were not affected by hydrocortisone. Stress doses of hydrocortisone may be a valuable immunomodulatory therapy for septic shock.

Adjuvants, Immunologic↗
PubMed2001

Effects of hypertonic saline on expression of human polymorphonuclear leukocyte adhesion molecules.

Hypertonic saline prevents vascular adherence of neutrophils and ameliorates ischemic tissue injury. We hypothesized that hypertonic saline attenuates N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated expression of adhesion molecules on human polymorphonuclear leukocytes (PMNLs). fMLP-stimulated up-regulation of beta2-integrins was diminished by hypertonic saline but not by hypertonic choline chloride-, mannitol-, or sucrose-modified Hanks' buffered salt solution. Shedding of L-selectin was decreased by hypertonic saline and choline chloride but not by hypertonic mannitol or sucrose. When the effects of hypertonic sodium chloride- and choline chloride-modified media were compared, neither solution affected fMLP-receptor binding but both equally inhibited fMLP-stimulated increase in intracellular calcium, ionophore A23187, and phorbol myristate acetate (PMA)-stimulated numerical up-regulation of beta2-integrins. Analysis of mitogen-activated protein (MAP) kinases p38 and p44/42 for phosphorylation revealed that hypertonic solutions did not differ in preventing fMLP-stimulated increases in phospho-p38 and phospho-p44/42. Resting PMNLs shrunk by hypertonic saline increased their volume during incubation and further during chemotactic stimulation. Addition of amiloride further enhanced inhibition of up-regulation of beta2-integrins. No fMLP-stimulated volume changes occurred in PMNLs exposed to hypertonic choline chloride, resulting in significant cell shrinkage. Results suggest a sodium-specific inhibitory effect on up-regulation of beta2-integrins of fMLP-stimulated PMNLs, which is unlikely to be caused by alterations of fMLP receptor binding, decrease in cytosolic calcium, attenuation of calcium or protein kinase C-dependent pathways, suppression of p38- or p44/42 MAP kinase-dependent pathways, or cellular ability to increase or decrease volumes.

CD18 Antigens↗
PubMed2000

[Inflammation and immunoparalysis. What are the differential criteria?].

Multiple organ failure (MOF) may occur early or late after trauma. Besides direct physical injury of organs, compromise of the microcirculation by inflammation plays an important role in the pathogenesis of MOF. Inflammation also induces counterregulatory responses which may end up in immunoparalysis. As a result, infection and sepsis with additional inflammatory damage to the microcirculation ensue thereby contributing to the late development of MOF. In addition to this biphasic model of posttraumatic MOF, there is evidence that inflammation and immunoparalysis do not only occur in sequence to each other but in parallel early after surgical procedures. The aim of the present brief review is to summarize the posttraumatic mechanisms of inflammation and immunoparalysis and to discuss how to differentiate between both pathophysiologic states.

Diagnosis, Differential↗
PubMed2000

Spectrum of mutations in the Fanconi anaemia group G gene, FANCG/XRCC9.

FANCG was the third Faconi anaemia gene identified and proved to be identical to the previously cloned XRCC9 gene. We present the pathogenic mutations and sequence variants we have so far identified in a panel of FA-G patients. Mutation screening was performed by PCR, single strand conformational polymorphism analysis and protein truncation tests. Altogether 18 mutations have been determined in 20 families - 97% of all expected mutant alleles. All mutation types have been found, with the exception of large deletions, the large majority is predicted to lead to shortened proteins. One stop codon mutation, E105X, has been found in several German patients and this founder mutation accounts for 44% of the mutant FANCG alleles in German FA-G patients. Comparison of clinical phenotypes shows that patients homozygous for this mutation have an earlier onset of the haematological disorder than most other FA-G patients. The mouse Fancg sequence was established in order to evaluate missense mutations. A putative missense mutation, L71P, in a possible leucine zipper motif may affect FANCG binding of FANCA and seems to be associated with a milder clinical phenotype.

Amino Acid Sequence↗
PubMed2000

Changes in intravascular volume during acute normovolemic hemodilution and intraoperative retransfusion in patients with radical hysterectomy.

BACKGROUND: Changes in blood volume during acute normovolemic hemodilution (ANH) and their consequences for the perioperative period have not been investigated sufficiently. METHODS: In 15 patients undergoing radical hysterectomy, preoperative ANH to a hematocrit of 24% was performed using 5% albumin solution. Intraoperatively, saline 0.9% solution was used for volume substitution, and intraoperative retransfusion was started at a hematocrit of 20%. Plasma volume (indocyanine green dilution technique), hematocrit, and plasma protein concentration were measured before and after ANH, before retransfusion, and postoperatively. Red cell volume (labeling erythrocytes with fluorescein) was determined before and after ANH and postoperatively. RESULTS: Mean normal plasma volumes (1,514 +/- 143 ml/m2) and reduced red cell volumes (707 +/- 79 ml/m2) were measured preoperatively. Blood (1,150 +/- 196 ml) was removed and replaced with 1,333 +/- 204 ml of colloid. Blood volume before and after ANH was equal and amounted to 3,740 ml. Intraoperatively, plasma volume did not increase until retransfusion despite infusing 3,389 +/- 1,021 ml of crystalloid (corrected for urine output) to compensate for an estimated surgical blood loss of 727 +/- 726 mi. Postoperatively, after retransfusion of all autologous blood, blood volume was 255 +/- 424 ml higher than preoperatively before ANH. Despite mean calculated blood loss of 1,256 +/- 892 ml, only one patient received allogeneic blood. CONCLUSIONS: During ANH, normovolemia was exactly maintained. After surgical blood loss of 1,256 +/- 892 ml, crystalloid and colloid supplies of 5,752 +/- 1,462 ml and 1,667 +/- 548 ml, respectively, and complete intraoperative retransfusions of autologous blood in every patient, mean blood volume was 250 ml higher than preoperatively before ANH.

Adult↗
PubMed1999

[Clinical manifestations of schizencephaly and its sonographic diagnosis].

Schizencephaly is defined as a cerebral malformation of the CNS with various clefts of the cerebral cortex. We report on two patients referred to our department with neurological abnormalities. In both cases the cranial sonography already provided for the clinical picture of schizencephaly. A MR-scan confirmed the diagnosis. In addition one of the patients proved to have a migrational disorder. The analysis of these cases and the relevant literature point out how difficult the etiologic differentiation is and, on the other hand, how various the manifestations of the malformation can be. The important role of cranial sonography as a screening method is shown.

Brain↗
PubMed1998

Specific inhibition of phorbol ester-stimulated phospholipase D by Clostridium sordellii lethal toxin and Clostridium difficile toxin B-1470 in HEK-293 cells. Restoration by Ral GTPases.

Activation of m3 muscarinic acetylcholine receptor (mAChR), stably expressed in human embryonic kidney (HEK)-293 cells, leads to phospholipase D (PLD) stimulation, a process apparently involving Rho GTPases, as shown by studies with Clostridium botulinum C3 exoenzyme and Clostridium difficile toxin B (TcdB). Direct activation of protein kinase C (PKC) by phorbol esters, such as phorbol 12-myristate 13-acetate (PMA), also induces PLD stimulation, which is additive to the mAChR action and which is only poorly sensitive to inactivation of Rho proteins by TcdB. To study whether Ras-like GTPases are involved in PLD regulation, we studied the effects of the TcdB variant TcdB-1470 and Clostridium sordellii lethal toxin (TcsL), known to inactivate Rac and some members of the Ras protein family, on PLD activities. TcdB-1470 and TcsL did not affect basal PLD activity and PLD stimulation by mAChR or direct G protein activation. In contrast, PMA-induced PLD stimulation was inhibited by TcdB-1470 and TcsL in a time- and concentration-dependent manner, without alteration in immunologically detectable PKC isozyme levels. In membranes of HEK-293 cells pretreated with TcdB-1470 or TcsL, basal and stable GTP analog-stimulated PLD activities measured with exogenous phosphatidylcholine, in the presence or absence of phosphatidylinositol 4,5-bisphosphate, were not altered. In contrast, pretreatment with TcdB-1470 and TcsL, but not TcdB, strongly reduced PMA-stimulated PLD activity. The addition of recombinant Rac1, serving as glucosylation substrate for TcdB, TcsL, and TcdB-1470, did not restore PLD stimulation by PMA. Furthermore, PMA-stimulated PLD activity, suppressed by prior treatment with TcdB-1470 or TcsL, was not rescued by the addition of recombinant Ras (RasG12V) or Rap proteins, acting as glucosylation substrates for TcsL only (Ras) or TcdB-1470 and TcsL (Rap). In contrast, the addition of recombinant Ral proteins (RalA and RalB), glucosylation substrates for TscL and TcdB-1470, but not for TcdB, to membranes of TcdB-1470- or TcsL-treated cells fully restored PLD stimulation by PMA without altering the strict MgATP dependence of PMA-induced PLD stimulation. RalA-mediated restoration of PMA-stimulated PLD activity in membranes of TcsL-treated cells was not enhanced by coaddition of RasG12V. In conclusion, the data presented indicate that TcdB-1470 and TcsL selectively interfere with phorbol ester stimulation of PLD and suggest an essential role of Ral proteins in PKC signaling to PLD in HEK-293 cells.

3T3 Cells↗
PubMed1998

Expression of adhesion molecules on circulating polymorphonuclear leukocytes during orthotopic liver transplantation.

After ischemia-reperfusion, polymorphonuclear leukocytes (PMNLs) become activated by inflammatory mediators, adhere to the vascular endothelium via the interaction of specific adhesion molecules, and cause tissue injury by the release of cytotoxic oxygen radicals and enzymes. Results obtained in animal experiments suggest a key role for PMNLs in ischemia-reperfusion injury of transplanted livers; therefore, we studied the expression of adhesion molecules on circulating PMNLs (beta2-integrins [CD18] and L-selectin [CD62L]) in 20 patients undergoing orthotopic liver transplantation (study group). To determine the effects of surgical trauma to the liver in the absence of ischemia and reperfusion, the expression of PMNL adhesion molecules was measured in 10 patients scheduled for elective partial liver resection without hepatic vascular exclusion (control group). Patients were classified as responders or nonresponders based on changes in the expression of adhesion molecules elicited by reperfusion. In the control group, all patients remained nonresponders, showing that surgical trauma of the liver alone does not cause activation of circulating PMNLs. In contrast, 8 of 20 patients in the study group were classified as responders. In responders, postoperative serum liver enzyme activities were significantly higher than in nonresponders, indicating that activation of PMNL was associated with damage to hepatocellular integrity. Because expression of adhesion molecules was already changed during surgery, monitoring of the expression of beta2-integrins and L-selectin on circulating PMNLs during orthotopic liver transplantation might be useful in prediction of early graft dysfunction.

Adolescent↗