Search PubMed⌕ Search

Biomedical subjects

S Walter

Publications and source records attributed to S Walter.

At least 19 recordsLinked to original sources
PubMed2006

Cyclooxygenase type 2 is increased in obstructed rat and human ureter and contributes to pelvic pressure increase after obstruction.

Prostanoids exert physiological effects on ureteral contractility that may lead to pressure changes and pain during obstruction. In the present study, we examined whether (1) obstruction changes the expression of the two cyclooxygenase (COX) isoforms, COX-1 and COX-2 in human and rat ureters and (2) administration of a selective COX-2 inhibitor influences the pelvic pressure change after experimental ureteral obstruction. Rats were subjected to bilateral ureter obstruction. Ureters were removed and dissected into a proximal dilated and distal non-dilated segment. RNA and protein were extracted and analyzed for cyclooxygenase expression by quantitative polymerase chain reaction and Western blotting. Human ureter samples were obtained from patients undergoing radical nephrectomy. Rat and human ureteral samples were processed for immunohistochemistry. COX-1, but not COX-2 mRNA, was readily detected in the normal rat ureter. COX-2 mRNA and protein expression was increased in the proximal dilated ureter compared to distal non-dilated ureter. This increased COX-2 expression was associated with increased urinary prostaglandin E2 (PGE2) excretion after release of obstruction. Immunohistochemistry showed increased COX-2 labeling in surface epithelium and smooth muscle layers in both rat and human obstructed ureters compared to control ureters. Furthermore, contractile PGE2-EP1 and thromboxane TP receptors were expressed in ureteral smooth muscle. Systemic treatment with the COX-2 selective inhibitor parecoxib (5 mg/kg/day) attenuated the pelvic pressure increase during obstruction. In summary, COX-2 expression is significantly increased in the ureteral wall in response to obstruction in the rat and human ureter and COX-2 activity contributes to increased pelvic pressure after obstruction.

Animals↗
PubMed2006

Size matters more than chemistry for cloud-nucleating ability of aerosol particles.

Size-resolved cloud condensation nuclei (CCN) spectra measured for various aerosol types at a non-urban site in Germany showed that CCN concentrations are mainly determined by the aerosol number size distribution. Distinct variations of CCN activation with particle chemical composition were observed but played a secondary role. When the temporal variation of chemical effects on CCN activation is neglected, variation in the size distribution alone explains 84 to 96% of the variation in CCN concentrations. Understanding that particles' ability to act as CCN is largely controlled by aerosol size rather than composition greatly facilitates the treatment of aerosol effects on cloud physics in regional and global models.

Journal Article↗
PubMed2006

Fibrinogen Denver: a dysfibrinogenemia associated with an abnormal Reptilase time and significant bleeding.

This paper reports a new dysfibrinogenemia with an unusual pattern of laboratory assays. The patient, a 51-year-old female with a lifelong moderate bleeding history, was initially diagnosed with von Willebrand disease based on routine coagulation assays and the clinical bleeding presentation. During recent testing as part of a preoperative screen and without any current history of treatment, levels of von Willebrand factor (VWF) antigen, VWF activity, and factor VIII activity were all significantly elevated, which was unexpected given her previous diagnosis. Additional testing was performed looking for other heritable causes for her considerable bleeding tendency. Interestingly, the patient had a significantly prolonged Reptilase time, minimally short thrombin time, and an abnormal fibrinogen-crossed immunoelectrophoresis pattern. Clearly, this patient had a fibrinogen abnormality that had been missed when only routine coagulation screening assays were performed. A brief review of the fibrinogen literature revealed no other dysfibrinogenemias reported with a similar pattern of test results, and thus this defect was designated fibrinogen Denver.

Afibrinogenemia↗
PubMed2006

Prospective open-label study of pharmacokinetics, efficacy and safety of a new 10% liquid intravenous immunoglobulin in patients with hypo- or agammaglobulinemia.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the pharmacokinetics, efficacy and safety of a newly developed 10% liquid immunoglobulin preparation in patients with primary immunodeficiency diseases. This new preparation for intravenous use includes three dedicated virus clearance steps in its manufacturing process to ensure a high margin of viral safety. MATERIALS AND METHODS: This was a prospective, open-label, non-controlled, multicentre study. Twenty-two subjects with primary immunodeficiency were treated initially with three infusions of a licensed intravenous immunoglobulin to standardize the immunoglobulin G (IgG) replacement therapy of all subjects to the same intravenous product. A total of nine infusions of the new 10% liquid preparation were subsequently administered. RESULTS: The median terminal half-life of total IgG following administration of the new preparation was 30.1 days. Median terminal half-lives for IgG subclasses IgG(1), IgG(2), IgG(3) and IgG(4) were 28.3, 31.3, 20.9 and 24.2 days, respectively. The median total serum IgG steady-state trough level was 8.51 g/l. No severe infection episodes started after initiation of treatment with the new preparation. The median rate of mild or moderate infection episodes was 0.48 per month. A total of 194 infusions with the new 10% liquid immunoglobulin preparation were administered. The mean dose per infusion was 0.41 g/kg body weight and the maximum infusion rates recorded were 8 ml/kg/h. Adverse experiences were mostly mild and unrelated to the study drugs. Only 4% of infusions with the new product were followed by one or more related adverse experiences. CONCLUSION: The new 10% liquid immunoglobulin preparation was well tolerated and shown to have an excellent pharmacokinetic, efficacy and safety profile. The liquid formulation provides convenience to patients and healthcare professionals.

Adult↗
PubMed2005

Major contribution of codominant CD8 and CD4 T cell epitopes to the human cytomegalovirus-specific T cell repertoire.

Human cytomegalovirus (HCMV) infection or reactivation is a cause of morbidity and mortality in immunocompromised individuals. In immunocompetent individuals, in contrast, HCMV is successfully controlled by specific CD8 and CD4 T cells. Knowledge of CD8 and CD4 T cell epitopes from HCMV and their immunodominant features is crucial for the generation of epitope-specific T cells for adoptive immunotherapy and for the development of a peptide-based HCMV vaccine. Therefore, we investigated the natural frequencies of a large number of CD8 and CD4 T cell epitopes, including 10 novel ones. We determined several epitopes as immunodominant. Surprisingly, no clear hierarchies were found for CD8 T cell epitopes, indicating codominance. These results will be valuable for adoptive transfer strategies and support initiatives towards development of a peptide-based HCMV vaccine.

CD4-Positive T-Lymphocytes↗
PubMed2005

Human peripheral blood mononuclear cells transfected with messenger RNA stimulate antigen-specific cytotoxic T-lymphocytes in vitro.

The efficiency of test vaccines needs to be evaluated by quantification of the triggered cellular immune response. Usually, for these assays, autologous target cells expressing the vaccine antigen are required. In the context of messenger RNA (mRNA)-based vaccinations, the target cells used for the read-out are mRNA-transfected monocyte-derived dendritic cells (Mo-DCs). Their production typically requires samples of 100 ml blood from the patients, and limits the number of assays that can be performed. We show here that fresh peripheral blood mononuclear cells (PBMCs) can be transfected with mRNA by electroporation. Such cells are as efficient as mRNA-transfected Mo-DCs for their ability to activate memory T cells in vitro. Thus, mRNA-transfected PBMCs are a convenient replacement of mRNA-transfected Mo-DCs for the in vitro monitoring of natural or vaccine-induced immune responses.

Antigen Presentation↗
PubMed2005

Breaking an absolute species barrier: transgenic mice expressing the mink PrP gene are susceptible to transmissible mink encephalopathy.

Transmissible mink encephalopathy (TME) is a rare disease of the North American mink, which has never been successfully transmitted to laboratory mice. We generated transgenic mice expressing the mink prion protein (PrP) and inoculated them with TME or the mouse-adapted scrapie strain 79A. TME infected mink PrP-transgenic mice on a murine PrP knockout background. The absolute species barrier between the infectious agent of TME and mice was therefore broken. Following TME and 79A infection of mice carrying both mink and murine PrP(C), only proteinase-resistant PrP homologous to the incoming agent was detectable. The presence of the murine PrP(C) prolonged the incubation time of TME substantially.

Animals↗
PubMed2004

Clinical experiences with desmopressin for long-term treatment of nocturia.

PURPOSE: To our knowledge we report the first long-term use of desmopressin for nocturia. Patients previously responding to desmopressin in short-term studies were enrolled in this long-term open label study. MATERIALS AND METHODS: Patients received treatment for 10 or 12 months with the optimal desmopressin dose (0.1, 0.2 or 0.4 mg orally at bedtime). Patients were followed a further month without treatment. Of the patients completing the short-term study 132 males (92%) and 117 females (83%) were recruited, and 95 (72%) and 87 (75%), respectively, completed long-term treatment. RESULTS: The mean number of nocturnal voids was decreased in males and females throughout the study (1.3 to 1.6 and 1.2 to 1.3) compared with baseline (3.1 and 2.9, respectively). After followup the number of voids increased after treatment cessation. From baseline to 12 months the mean duration of the first sleep period gradually increased in males (157 to 288 minutes) and females (142 to 310 minutes). After followup the mean duration of the first sleep period decreased, confirming that it was a treatment related benefit. Desmopressin was well tolerated with few males (14%) or females (10%) withdrawing due to adverse events. Most adverse events were mild (44%) or moderate (44%) in severity. Four males experienced serious drug related adverse events, namely dizziness in 1, cardiac failure, headache and vomiting in 2, and chest pain and hypertension in 1. A female experienced 4 serious drug related adverse events, that is hyponatremia, headache, nausea and vertigo. Two patients had clinically significant hyponatremia. CONCLUSIONS: This long-term study shows that desmopressin is a generally well tolerated and effective treatment for nocturia.

Adult↗
PubMed2003

The LPS receptor (CD14) links innate immunity with Alzheimer's disease.

To rapidly respond to invading microorganisms, humans call on their innate immune system. This occurs by microbe-detecting receptors, such as CD14, that activate immune cells to eliminate the pathogens. Here, we link the lipopolysaccharide receptor CD14 with Alzheimer's disease, a severe neurodegenerative disease resulting in dementia. We demonstrate that this key innate immunity receptor interacts with fibrils of Alzheimer amyloid peptide. Neutralization with antibodies against CD14 and genetic deficiency for this receptor significantly reduced amyloid peptide induced microglial activation and microglial toxicity. The observation of strongly enhanced microglial expression of the LPS receptor in brains of animal models of Alzheimer's disease indicates a clinical relevance of these findings. These data suggest that CD14 may significantly contribute to the overall neuroinflammatory response to amyloid peptide, highlighting the possibility that the enormous progress currently being made in the field of innate immunity could be extended to research on Alzheimer's disease.

Alzheimer Disease↗
PubMed2003

Morphological and populational characteristics of hemocytes of Ornithodoros moubata nymphs during the ecdysial phase.

The ultrastructure and characteristics of hemocytes of argasid tick species, Ornithodoros moubata, during the ecdysdial phase are herein presented. Hemocyte classes/populations characterized based on their affinity with Giemsa stain and ultrastructural differences comprised the prohemocytes, nongranular cells (Nc), eosinophilic granular cells (Ec), basophilic granular cells (Bc), and unidentified cells. Significant changes/shift in the ratio of hemocyte classes/population was apparent in ticks before and after the ecdysial phase. The granule-scant basophilic granular cells (sBc) constituted the most abundant hemocyte population in the ecdysial phase. Nymphs in ecdysis showed increases in Nc and sBc and decrease in Ec, a phenomenon that was reversed in unengorged nymphs and adults ticks. The significant increase in total Bc population in ecdysis relative to nonengorged ticks clearly point to blastogenesis of Bc taking place during the ecdysial phase and Bc's important role in the process of tissue remodeling.

Animals↗
PubMed2002

Effects of statins on human cerebral cholesterol metabolism and secretion of Alzheimer amyloid peptide.

Cerebral cholesterol metabolism has been linked with production of amyloid peptide (Abeta) crucial in AD. The association between use of cholesterol-lowering drugs (statins) and AD disease is currently being intensely discussed. In this case-control study on elderly nondemented subjects, the authors provide the first evidence that statins in clinically relevant dosages indeed affect cerebral cholesterol metabolism. However, these changes were not associated with altered intrathecal secretion of Alzheimer Abeta.

Aged↗
PubMed2002

Structure and function of the GroE chaperone.

The Escherichia coli proteins GroEL and GroES were the first chaperones to be studied in detail and have thus become a role model for assisted protein folding in general. A wealth of both structural and functional data on the GroE system has been accumulated over the past years, enabling us now to understand the basic principles of how this fascinating protein-folding machine accomplishes its task. According to the current model, GroE processes a nonnative polypeptide in a cycle consisting of three steps. First, the polypeptide substrate is captured by GroEL. Upon binding of the co-chaperone GroES and ATP, the substrate is then discharged into a unique microenvironment inside of the chaperone, which promotes productive folding. After hydrolysis of ATP, the polypeptide is released into solution. Moreover, GroE may actively increase the folding efficiency, e.g. by unfolding of misfolded protein molecules. The mechanisms underlying these features, however, are yet not well characterized.

Bacterial Proteins↗
PubMed2002

High frequency of human cytomegalovirus (HCMV)-specific CD8+ T cells detected in a healthy CMV-seropositive donor.

Human cytomegalovirus (HCMV) persists after infection but is controlled by cellular immune responses, particularly by CD8+ T cells. If infected individuals are immunosuppressed, HCMV can be reactivated. Upon testing the blood of healthy donors with human lymphocyte antigen tetramers, we found one individual with about 50% of his CD8+ T cells being specific for the immunodominant pp65 epitope NLVPMVATV Over a period of 2 years the high level of HCMV-specific T cells was maintained, and no HCMV DNA could be detected. At one timepoint, however, HCMV-specific DNA was detected, while 65% of CD8+ T cells were specific for HCMV. When virus was detectable, a lower percentage of HCMV-specific CD8+ T cells showed interferon gamma (IFN-gamma) production after peptide stimulation in vitro. These data suggest that HCMV reactivation may also occur in immunocompetent persons, accompanied by the presence of HCMV-specific CD8+ T cells which are not producing IFNy, and therefore potentially anergic or in vivo exhausted.

Blood Donors↗
PubMed2002

Nosocomial neonatal outbreak of Serratia marcescens--analysis of pathogens by pulsed field gel electrophoresis and polymerase chain reaction.

BACKGROUND: We investigated an outbreak of Serratia marcescens in the neonatal intensive care unit (NICU) and the pediatric intensive care unit (ICU) of the University Children's Hospital Leipzig, Germany. PATIENTS AND METHODS: From September to November 1998 15 patients were infected or colonized by S. marcescens. During the outbreak swabs from eye, blood, throat and nose were taken from every patient hospitalized in the ICUs. RESULTS: In 15 cases (14 from the NICU and one from the pediatric ICU) the cultures yielded S. marcescens. All strains were investigated by pulsed field gel electrophoresis (PFGE) as well as by polymerase chain reaction (PCR) fingerprinting. Both molecular typing methods revealed corresponding fingerprint patterns in all of the 15 isolates. Typing results of the outbreak-related isolates demonstrated that two epidemic strains of distinct genotypes were associated with cross-infections of a group of five and a group of ten patients, respectively. The three invasive and seven of the colonizing isolates were related genotypically. CONCLUSION: This survey shows that PCR and PFGE are comparable in respect to the discrimination and reproducibility for epidemiological studies of S. marcescens strains in nosocomial outbreaks. Genotypic fingerprinting of bacterial isolates is useful and important to limit nosocomial infections. Fingerprinting sources of nosocomial infections can be traced both by PFGE and PCR. All patients infected recovered completely and the nosocomial outbreak could be stopped rapidly.

Cross Infection↗
PubMed2002

Efficacy of desmopressin in the treatment of nocturia: a double-blind placebo-controlled study in men.

OBJECTIVE: To investigate the efficacy and safety of oral desmopressin in the treatment of nocturia in men. PATIENTS AND METHODS: Men aged >/=18 years with verified nocturia (>or=two voids/night) and nocturnal urine production greater than their maximum functional bladder capacity were recruited. A 3-week dose-titration phase established the optimum desmopressin dose (0.1, 0.2 or 0.4 mg). After a 1-week 'washout' period, patients who responded in the dose-titration period were randomized to receive the optimal dose of desmopressin or placebo in a double-blind design for 3 weeks. RESULTS: In all, 151 patients entered the double-blind period (86 treated with desmopressin, 65 with placebo). In the desmopressin group 28 (34%) patients and in the placebo group two (3%) patients (P<0.001) had fewer than half the number of nocturnal voids relative to baseline; the mean number of nocturnal voids decreased from 3.0 to 1.7 and from 3.2 to 2.7, respectively, reflecting a mean decrease of 43% and 12% (P<0.001). The mean duration of the first sleep period increased by 59% (from 2.7 to 4.5 h) in the desmopressin group, compared with an increase of 21% (from 2.5 to 2.9 h) in the placebo group (P<0.001). The mean nocturnal diuresis decreased by 36% (from 1.5 to 0.9 mL/min) in the desmopressin group and by 6% (from 1.7 to 1.5 mL/min) in the placebo group (P<0.001). The mean ratio of night/24-h urine volume decreased by 23% and 1% (P<0.001), and the mean ratio of night/day urine volume decreased by 27% and increased by 3% (P<0.001) for the desmopressin and placebo groups, respectively. In the double-blind treatment period, similar numbers of patients had adverse events; 15 (17%) patients in the desmopressin and 16 (25%) patients in the placebo group. Most adverse events were mild. Serum sodium levels were <130 mmol/L in 10 (4%) patients and this occurred during dose-titration. CONCLUSIONS: Orally administered desmopressin is an effective and well-tolerated treatment for nocturia in men.

Administration, Oral↗
PubMed2002

A population-based study on bowel habits in a Swedish community: prevalence of faecal incontinence and constipation.

BACKGROUND: The self-reported bowel habits and the prevalence of faecal incontinence and constipation in men and women between the ages of 31 and 76 are assessed. METHODS: A postal questionnaire was sent to a random sample (n = 2000) of the total population of persons between the ages of 31 and 76 living in the County of Ostergötland, Sweden. RESULTS: The response rate was 80.5%. Overall, 67.8% reported one bowel movement per day and 4.4% had more than 21 or less than 3 bowel movements per week. This means that 95.6% had between 3 bowel movements a day to 3 bowel movements a week. Among women, 4.3%, and among men. 1.7%, reported less than 3 bowel movements per week. Women and men used the same terms to describe the definition of constipation. Women had a significantly higher self-reported prevalence of constipation than men (P < 0.0001). About 20% of all women considered themselves constipated. The use of laxatives increased with age and 22% and 10% of elderly women and men, respectively, used laxatives including bulking agents for at least every fourth toilet procedure. About 10% reported leakage of faeces more often than once a month in the case of loose stools. With solid faeces, the rate of leakage was 1.4% and 0.4% for women and men, respectively. Soiling of underclothes more than once a month occurred in 21% of men and in 14.5% of women (P = 0.006) and involuntary daily leakage of gas in 5.9% of men and 4.9% of women (n.s.). CONCLUSIONS: Constipation and faecal incontinence are common problems in a general Swedish population.

Adult↗