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Biomedical subjects

E Schwarz

Publications and source records attributed to E Schwarz.

At least 19 recordsLinked to original sources
PubMed2006

Structural and functional properties of mouse proNGF.

The unprocessed pro-form of the NGF (nerve growth factor), proNGF (NGF precursor, without signal peptide), has been suggested to have additional functions distinct from its role as a promoter of protein folding, i.e. apoptosis and/or neurotrophic activity. Aiming to gain insights into the specific molecular interactions that mediate proNGF biological activity and into the structural determinants stabilizing its pro-region, rm-proNGF (recombinant mouse proNGF) was expressed in Escherichia coli, refolded in vitro and characterized by physicochemical methods. X-ray solution scattering measurements (small angle X-ray scattering) revealed that rm-proNGF is dimeric in solution and appears to be anisometric when compared with the compact structure of the NGF dimer. Two structural models, a globular crab-like shape and an elongated rod-like shape, equally fit to the experimental results, pointing to an intrinsically structural disordered pro-region of NGF. The models obtained allowed the interpretation of TrkA (tropomyosin receptor kinase A) binding and activation assays in cell cultures, shedding new light on the key role of proNGF in neuronal survival and neurodegeneration.

Animals↗
PubMed2005

Effect of oral administration of freshly pressed juice of Echinacea purpurea on the number of various subpopulations of B- and T-lymphocytes in healthy volunteers: results of a double-blind, placebo-controlled cross-over study.

BACKGROUND: In a recent double-blind placebo-controlled crossover-study the "immune stimulatory" effects (activation of macrophages leading to enhanced phagocytosis and production of several cytokines) of Echinacea purpurea preparations (EPP) which were observed in vitro experiments and following parenteral administration could not be confirmed following oral application of the drug in healthy volunteers. The aim of the present study was to investigate whether or not oral EPP has any effect on important lymphocyte-subpopulations. SUBJECTS AND METHODS: Forty healthy male volunteers (age range 20-40 years) participated in the study. They received either a commercially available pressed juice of E. purpurea herbs or placebo juice using a double-blind placebo-controlled cross-over design with two treatment periods of 14 days. The total number of lymphocytes and 12 subgroups of lymphocytes were determined by using Flow-cytometry. RESULTS: After 1 week of treatment with verum the mean value of the total number of lymphocytes decreased slightly (-6%, p = 0.033) compared to the initial value. Treatment for 1 and 2 weeks with EPP had only minor effects on two of the 12 subtypes of lymphocytes. No significant changes were observed in the verum period for the following types of cells: T- and B-lymphocytes, CD4 + - and CD8 + -T-lymphocytes including the subgroups of "naive" and "memory" CD4 + - and CD8 + -T-lymphocytes as well as the natural killer cells. Using a modified version of the Wilcoxon-Mann-Whitney-U-test, which is claimed to be optimal for the evaluation of the results of studies with a cross-over design, a significant difference was found for the number of CD8 + -T-lymphocytes and natural killer cells corresponding to either a decrease during treatment with verum or an increase in the number of these cells in the placebo period. CONCLUSION: Oral administration of EPP for 1 and 2 weeks has only minor effects on two out of 12 lymphocyte subpopulations determined in the study. The small differences observed in the number of CD8 + -T lymphocytes and natural killer cells are only of questionable physiological relevance.

Adjuvants, Immunologic↗
PubMed2005

Randomized placebo-controlled trial of a flavonoid-rich plant extract-based cream in the treatment of rosacea.

BACKGROUND: Biological research suggests that vascular changes may play a major role in rosacea pathogenesis. Chrysanthellum indicum is a plant-based extract containing a unique combination of phenylpropenoic acids, flavonoids and saponosids, and has a well-documented effect on vascular wall permeability and increase of the mechanical resistance of capillaries. OBJECTIVE: To determine the efficacy and safety of a cream containing 1%C. indicum extract with vitamin P properties in the treatment of rosacea. METHODS: This study included 246 patients diagnosed clinically as having moderate rosacea. Patients were randomly allocated to C. indicum extract-based cream (n = 125) and placebo (n = 121) groups. Patients were advised to apply the products on their face twice a day for a 12-week period. The patients were examined at the end of each 4-week period. Severity of erythema (graded by reference to six photographs), surface of erythema and rosacea overall severity scores were recorded at each visit on days 0, 28, 56 and 84. Investigators carried out a final efficacy assessment at the end of week 12. Volunteers' final overall efficacy assessment was recorded in a self-administered questionnaire. Adverse events were identified through examination, interview and collection of comments in patients' questionnaires. RESULTS: Treatment with the C. indicum extract-based cream resulted in significant improvement (P < 0.05) in severity of erythema, overall rosacea severity compared to baseline and placebo, and investigator and patient overall efficacy assessment scores (P = 0.046 and P = 0.001, respectively) compared with placebo scores. Adverse reactions were mild, and did not differ between the C. indicum extract-based cream and the placebo groups. CONCLUSION: Chrysanthellum indicum extract-based cream is an effective and well-tolerated topical agent for the treatment of moderate rosacea. The mode of action of the active ingredient suggests that additional efficacy might be expected from combination with other topical treatments.

Administration, Topical↗
PubMed2003

Differences in the cytokine profiles associated with prostate cancer cell induced osteoblastic and osteolytic lesions in bone.

Prostate adenocarcinoma is associated with the formation of osteoblastic metastases in bone. It is hypothesized that osteoclastogenesis is a critical component in the development of skeletal metastases. These findings, however, were generally noted in predominantly osteolytic lesions. The pathophysiology of osteoblastic lesions remains unknown but the type of bone lesion formed may be influenced by the cytokines produced by prostate tumors. To test this theory, we implanted PC-3 and LAPC-9 cells into the tibias of SCID mice. These mice were sacrificed at 1, 2, 4, 6, and 8 weeks after implantation and histologic analysis was performed on these tibias. PCR analysis was also performed on bulk tumors. The results showed that the PC-3 implanted tibias developed pure osteolytic lesions while the LAPC-9 implanted tibias developed pure osteoblastic lesions on radiographs. Analysis of tibias after injection with PC-3 cells revealed progressive osteolytic lesions with abundant osteoclast activity at 2 weeks and destruction of the proximal tibia at 6 weeks after cell implantation. In contrast, the LAPC-9 cells formed osteoblastic lesions six weeks after cell injection. There were rare osteoclasts prior to the establishment of the osteoblastic lesions but greater osteoclast activity was noted with remodeling of the osteoblastic lesion 8 weeks after implantation of the tumor cells. PCR analysis revealed that PC-3 cells produced RANKL, IL-1, and TNF-alpha, which are associated with osteoclastogenesis. In contrast, LAPC-9 cells produced osteoprotegerin, which blocks osteoclast production and no detectable levels of RANKL or IL-1 and only minimal amounts of TNF-alpha were noted. These cells secreted BMP-2, -4, -6, and IL-6, which are associated with bone formation. These results suggest that the role of the osteoclast in the development of a metastatic lesion is variable depending on the phenotype of the prostate cancer cells, and that tumor-induced osteolysis may not be required for osteoblastic metastases.

Animals↗
PubMed2002

Mechanisms of nordihydroguaiaretic acid-induced growth inhibition and apoptosis in human cancer cells.

Lipoxygenase metabolites of arachidonic acid can act as growth promoting factors for various cancer cell lines. Here we demonstrate that the 5-lipoxygenase inhibitor nordihydroguaiaretic acid potently inhibits anchorage-independent growth of human pancreatic and cervical cancer cells in soft agar and delays growth of pancreatic and cervical tumours established in athymic mice. Furthermore, nordihydroguaiaretic acid induces apoptosis of these cancer cells in vitro and in vivo. Potential mechanisms mediating these effects of nordihydroguaiaretic acid were examined. Nordihydroguaiaretic acid had no inhibitory effect on growth and survival signals such as tyrosine phosphorylation of the epidermal growth factor receptor or basal and growth factor-stimulated activities of extracellular signal-regulated kinase 1/2, p70(s6k) and AKT but selectively inhibited expression of cyclin D1 in the cancer cells. In addition, treatment with nordihydroguaiaretic acid lead to a disruption of the filamentous actin cytoskeleton in human pancreatic and cervical cancer cells which was accompanied by the activation of Jun-NH(2)-terminal kinase and p38(mapk). Similar effects were obtained by treatment of the cancer cells with cytochalasin D. These results suggest that nordihydroguaiaretic acid induces anoikis-like apoptosis as a result of disruption of the actin cytoskeleton in association with the activation of stress activated protein kinases. In conclusion, nordihydroguaiaretic acid could constitute a lead compound in the development of novel therapeutic agents for various types of cancer.

Actins↗
PubMed2002

[Kidney calculus episode in a supernumerary 3rd kidney].

Supernumerary kidney is a rare renal anomaly. As a distinct encapsulated parenchymatous mass, this free accessory organ has a separate blood supply and excretory duct system. We report on a patient who presented with an acute episode of abdominopelvic pain, secondary to hydronephrosis of a third kidney, situated in the pelvis behind the bladder. Modern diagnostic methods assisted in the conservative management of this well functioning third kidney.

Humans↗
PubMed2001

NKG2D receptors induced by IL-15 costimulate CD28-negative effector CTL in the tissue microenvironment.

Unlike primary T cells in lymph nodes, effector CD8(+) CTL in tissues do not express the costimulatory receptor CD28. We report that NKG2D, the receptor for stress-induced MICA and MICB molecules expressed in the intestine, serves as a potent costimulatory receptor for CTL freshly isolated from the human intestinal epithelium. Expression and function of NKG2D are selectively up-regulated by the cytokine IL-15, which is released by the inflamed intestinal epithelium. These findings identify a novel CTL costimulatory pathway regulated by IL-15 and suggest that tissues can fine-tune the activation of effector T cells based on the presence or absence of stress and inflammation. Uncontrolled secretion of IL-15 could lead to excessive induction of NKG2D and thus contribute to the development of autoimmune disease by facilitating the activation of autoreactive T cells.

CD28 Antigens↗
PubMed2001

Scaling laws in two-dimensional turbulent convection.

Two-dimensional homogeneous turbulent convection is studied numerically. Though Bolgiano-Obukhov scaling is approximately valid, strong differences exist in the intermittency properties of velocity and temperature increments, where the latter are similar to those of a passive scalar. The main difference of the small-scale dynamics compared to a passive scalar arises from the Kelvin-Helmholtz instability, but this process does not affect the scaling properties. A condition for a scalar field to show the ramp-and-cliff structures of a passive scalar is discussed.

Journal Article↗
PubMed2001

Pro-sequence assisted folding and disulfide bond formation of human nerve growth factor.

Nerve growth factor (NGF) is a member of the neurotrophin family. These growth factors support neuronal survival and differentiation. Neurotrophins are synthesized as pre-pro-proteins. Whereas the pre-sequences mediate secretion, the function of the pro-peptides is largely unknown. To test the role of the pro-sequence as a folding enhancer, recombinant human pro-NGF (rh-pro-NGF) was produced in Escherichia coli. The oxidative refolding of rh-pro-NGF and rh-NGF was studied using electrospray mass spectrometry (ESIMS) time-course analysis. This analysis permitted both the identification and quantification of intermediates present during the process. The disulfide bonds formed at different times of the refolding processes were characterized by proteolytic digestion followed by matrix assisted laser desorption ionization mass spectrometry (MALDIMS) analysis. Folding yields and kinetics of rh-pro-NGF were significantly enhanced when compared to the in vitro refolding of mature rh-NGF. These results suggest that the pro-sequence of NGF promotes folding of the mature part.

Alkylation↗
PubMed2001

Assessment of murine bladder permeability with fluorescein: validation with cyclophosphamide and protamine.

OBJECTIVES: Bladder hyperpermeability should result in elevated blood levels of intravesically administered agents. Reabsorption from a hyperpermeable bladder should result in prolonged urinary excretion of an agent after parenteral administration. To test these hypotheses, urinary clearance and plasma levels of sodium fluorescein (NaF) were measured in mice before and during cyclophosphamide (CYP) and protamine-induced hemorrhagic cystitis. METHODS: To measure the plasma uptake of NaF from the bladder, 10 mg/mL NaF was instilled, either by catheter or retrograde urethral infusion, 15 minutes before retro-orbital or ventricular sampling. The plasma levels were measured 24 hours and 14 days after exposure to CYP 300 mg/kg or 15 minutes after instillation of protamine 10 mg/mL. Hourly urine concentrations were measured immediately after intraperitoneal administration of 10 mg/kg NaF. Pretreatment samples were compared with those obtained 24 hours after intraperitoneal administration of 300 mg/kg CYP. RESULTS: Urinary NaF excretion was delayed in CYP-exposed mice. A bi-exponential model provided an appropriate fit of the data, both before and after CYP administration. The plasma levels of NaF were significantly elevated at 24 hours and 14 days after CYP exposure when sampled by ventricular nick or retro-orbitally. The median concentration of fluorescein in the protamine-treated mice was significantly higher than in the control mice. CONCLUSIONS: Fluorescein can be used to measure alterations in bladder permeability after bladder mucosal injury in mice. Urinary excretion of NaF is a bi-exponential process that is delayed after bladder mucosal injury, presumably because of increased mucosal permeability and resorption from the urine into the bloodstream.

Analysis of Variance↗
PubMed2001

Oral health and dental care in modern-day China.

The purpose of this paper is to present salient background information on the oral care situation and organization in China and to review epidemiological literature that has been published on adults in Chinese dental journals during the last 20 years as a context for understanding ongoing oral health research activities in China. Searches were conducted through Medline as well as Chinese language catalogues and around 30 Chinese dental journals. Most oral health surveys on adults were conducted after 1970 mainly on residents living in big cities, which are also the location of major medical universities. Surveys conducted among farmers were uncommon. Dental caries and periodontal disease were the major dental diseases studied. Only a few surveys on people's oral health knowledge, attitudes and behavior were conducted. Papers concerning dental treatment needs and utilization of dental services among adults were scarce. Sample size was usually not a major problem in these surveys but the sampling methods and diagnostic criteria used were often poorly defined. Mean DMFT scores between 2 and 6 were reported in the 35-44-year-olds and between 9 and 16 in the elderly younger than 75 years. Calculus and gingivitis were reported to be common in adult Chinese; the proportion of subjects with shallow and deep periodontal pockets was not high. Complete edentulousness in the 60-69-year-olds was usually reported to be less than 10%. About 14% of the 35-44-year-olds and 19% of the 65-74-year-olds did not brush their teeth daily.

China↗
PubMed2001

Characteristics and study motivation of Danish dental students in a longitudinal perspective.

This survey encompasses 3 comparable datasets of newly admitted dental students in 1972 (n=236), 1982 (n=197), and 1994 (n=108). The objectives of the survey were to describe selected socio-demographic characteristics of dental students and to analyze possible changes over time as well as possible changes in the reasons reported by the students for choosing dentistry as a career, their motivations and their expectations concerning the study and the profession of dentistry. The results showed that the ratio of women to men remained unchanged at 6:4 in all 3 cohorts of students and that the students were increasingly recruited from the 2 upper social classes. The motives for choosing dentistry mainly included altruistic motives, the desire for varied work with the opportunity to put theory into practice, economic rewards, and the implicit social status. Compared to the 1972 students, those in 1994 placed greater emphasis on social status as a motive, on the opportunity to work in the biological and scientific field, and on the ready availability of work outside Denmark. The students in all 3 years had strong altruistic motives for choosing dentistry, and it would seem that this stable continuity in the cohort of dental students would ensure the continuous controlled development of dentistry in the new millennium.

Adolescent↗
PubMed2001

The pro-sequence facilitates folding of human nerve growth factor from Escherichia coli inclusion bodies.

Nerve growth factor (beta-NGF), a neurotrophin required for the development and survival of specific neuronal populations, is translated as a prepro-protein in vivo. While the presequence mediates translocation into the endoplasmic reticulum, the function of the pro-peptide is so far unknown. As the pro-sequences of several proteins are known to promote folding of the mature part, the renaturation behaviour of recombinant human beta-NGF pro-protein was compared to that of the mature form. Expression of rh-pro-NGF in Escherichia coli led to the formation of inclusion bodies (IBs). The presence of the covalently attached pro-sequence significantly increased the yield and rate of refolding with concomitant disulfide bond formation when compared to the in vitro refolding of mature NGF (rh-NGF). Physicochemical characterization revealed that rh-pro-NGF is a dimer. The pro-peptide could be removed by limited proteolysis with trypsin yielding biologically active, mature rh-NGF. Furthermore, rh-pro-NGF exhibited biological activity in the same concentration range as rh-NGF.

Electrophoresis, Polyacrylamide Gel↗
PubMed2001

Automated noninvasive measurement of cyclophosphamide-induced changes in murine voiding frequency and volume.

PURPOSE: We developed an automated noninvasive method for studying bladder function in mice. Changes in voided volume and frequency accompanying cyclophosphamide-induced cystitis were measured using computerized digital balances. MATERIALS AND METHODS: Eight CRL CD-1 mice were given a solution of glucose and saccharin to increase urine output and studied during the dark cycle, when most voiding occurs. Urine fell directly onto electronic balance pans. The time and weight of each void was recorded. Computer programs adjusted for evaporative loss analyzed voiding data within and across sessions. After establishing stable voiding patterns 300 mg./kg. cyclophosphamide were administered intraperitoneally. The Wilcoxon signed rank test was done to compare median voided volumes, frequency and gm. per hour of urine produced before and after cyclophosphamide. RESULTS: We implemented an automated method for voiding studies in mice. After cyclophosphamide administration the number of voids per hour increased and voided volume decreased. Some mice had as much as a 70% decrease in bladder volume and a tripling of urinary frequency. Mice responded by a sustained elevation in frequency and decreased voided volume as early as 24 hours after cyclophosphamide administration or by a pattern of delayed toxicity. CONCLUSIONS: This noninvasive technique measures changes in mouse voiding patterns with great sensitivity and minimal effort. The method is applicable to murine models of interstitial cystitis, detrusor instability and other abnormal voiding states. It may be used for evaluating potential therapies for such conditions.

Animals↗
PubMed2001

Cosecretion of chaperones and low-molecular-size medium additives increases the yield of recombinant disulfide-bridged proteins.

Attempts were made to engineer the periplasm of Escherichia coli to an expression compartment of heterologous proteins in their native conformation. As a first approach the low-molecular-size additive L-arginine and the redox compound glutathione (GSH) were added to the culture medium. Addition of 0.4 M L-arginine and 5 mM reduced GSH increased the yield of a native tissue-type plasminogen activator variant (rPA), consisting of the kringle-2 and the protease domain, and a single-chain antibody fragment (scFv) up to 10- and 37-fold, respectively. A variety of other medium additives also had positive effects on the yield of rPA. In a second set of experiments, the effects of cosecreted ATP-independent molecular chaperones on the yields of native therapeutic proteins were investigated. At optimized conditions, cosecretion of E. coli DnaJ or murine Hsp25 increased the yield of native rPA by a factor of 170 and 125, respectively. Cosecretion of DnaJ also dramatically increased the amount of a second model protein, native proinsulin, in the periplasm. The results of this study are anticipated to initiate a series of new approaches to increase the yields of native, disulfide-bridged, recombinant proteins in the periplasm of E. coli.

Culture Media↗