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Complete Elimination (complete + elimination)

Distribution by Scientific Domains

Life Sciences	43%
Medical Sciences	34%
Chemistry	17%

Selected Abstracts

Complete elimination of carbonates: A critical step in the accurate measurement of organic and black carbon in sediments

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2005
Marta T. Lukasewycz
Abstract Accurate measurement of organic carbon (OC) and black carbon (BC) in sediments requires the complete removal of coexisting inorganic carbonates from the sample before instrumental analysis. The removal of carbonates from sediments is achieved with acidification, which causes the dissolution and decomposition of carbonates with accompanying effervescence. This effervescence, or the lack of it, is commonly used as an indicator for the presence or absence of carbonates. We have found that the lack of effervescence endpoint used with the direct acidification method (adding aliquots of acid to samples) is not a reliable indicator for complete removal of carbonates from sediment samples. The ineffectiveness of the lack of effervescence endpoint, we believe, is caused by the presence of carbonates with dissolution rates much slower than those of calcite, resulting in much slower rates of visible effervescence. We propose and demonstrate a method for determining the amount of acid required for complete elimination of all carbonates using Lake Michigan (USA) sediment samples. Based on our experiences with the lack of effervescence endpoint, we recommend that in any scheme for analysis of OC and/or BC, a minimum of two samples be treated with three different levels of acidification, with the lowest level being the same as that planned for all the OC and/or BC analyses. There can be no significant differences among the OC and BC contents measured using the three different levels of acidification. [source]

Reduced intensity allogeneic stem cell transplantation for systemic primary amyloidosis refractory to high-dose melphalan

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2004
Yasukazu Kawai
Abstract: Complete elimination of the plasma cell dyscrasia is a rational therapeutic goal, as intercepting supply of precursor protein is a necessary condition for a major regression of amyloid deposits. High-dose melphalan with autologous stem cell transplantation has shown the ability to induce complete hematological response (HR) along with recovery of organ dysfunction. However, the rate of HR with this treatment rarely exceeds 40%. We describe here the first known case of successful reduced intensity allogeneic stem cell transplantation (RIST) for a patient with primary amyloidosis complicated with nephrotic syndrome but without cardiac disease, who had obtained only partial HR by high-dose melphalan with autologous stem cell transplantation. RIST may be feasible and be capable of achieving complete HR along with recovery from nephrotic syndrome with acceptable toxicity. [source]

A high sensitivity pinhole camera for soft condensed matter

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2003
Thomas Zemb
A significant improvement in the sensitivity of a Huxley-Holmes design for a small angle X-ray scattering camera is obtained by separating the mirror and the monochromator. The "separated optics" camera described in this paper involves a long X-ray mirror close to a point X-ray source associated with a curved focusing crystal located close to the sample. The sample area is located at half the distance between the source and detector planes. Diffuse scattering produced by the mirror is not incident on the focusing crystal, thus reducing the background signal. Complete elimination of hard X-rays allows precise calibration and hence absolute determination of sample cross-section by means of a semi-transparent beam-stop. In pinhole geometry, the flux corresponds to a ca. 107 photons/s through the sample, collimated to q=10 -2 Å -1 in scattering vector range. This allows determination of scattered intensities of the order of 10 -3 cm -1, corresponding to the scattering related to isothermal compressibility of less than 0.1 mm of pure water. Values of absolute intensities for water as well as convenient widespread buffer solutions are shown, in order to be usable for calibration as secondary standards. As solid reference sample, the widely studied Lupolentm, a semi-crystalline polymer- is calibrated. The high- q limit (q, 4.5 nm,1 ) of a porous calcite sample can be used as a secondary standard for specific area determination of solid/solid or solid-liquid dispersions. [source]

Impacts of WTO restrictions on subsidized EU sugar exports

AGRICULTURAL ECONOMICS, Issue 3 2000
Daneswar Poonyth
Abstract The study evaluates the impact of World Trade Organization (WTO) restrictions on the European Union (EU) sugar sector and the world sugar market. A small reduction in production quotas would be sufficient to satisfy the export subsidy limitations of the Uruguay Round agreement. Complete elimination of export subsidies by 2005 would require either a 10% reduction in production quotas or the combination of an 8% reduction in quotas and an 11% reduction in intervention prices. Higher world prices resulting from reduced EU exports would result in increased production of unsubsidized C-sugar, with different impacts across EU member countries explained by differences in institutional pricing arrangements and marginal production costs. [source]

Complete elimination of carbonates: A critical step in the accurate measurement of organic and black carbon in sediments

Co-administration of immunomodulator tuftsin and liposomised nystatin can combat less susceptible Candida albicans infection in temporarily neutropenic mice

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2004
Masood A Khan
Abstract In order to develop a prospective chemotherapeutic agent against opportunistic infections, it is important to know that host factors such as degree of immunological debility as well as recovery of immune functions to normality may contribute significantly to a successful elimination of the pathogens. We demonstrated previously that concomitant delivery of antimicrobial agents and immunomodulators to the pathogen harbouring-host contributes to the complete elimination of the deep-seated fungal infections (aspergillosis and candidiasis) in animals with normal immune status. Considering that neutropenic hosts are the main targets of such infections, it can be argued about the potential of the immunomodulator-based therapy in subjects with non-functional immune system. To resolve the hypothesis, we studied the role of immunomodulator tuftsin against experimental murine candidiasis in temporarily neutropenic Balb/c mice. The neutropenic mice were challenged with an isolate of Candida albicans that was showing less susceptibility to both free and liposomised-amphotericin B. The co-administration of tuftsin increased the efficiency of liposomised-polyene antibiotics (nystatin and amphotericin B) against experimental murine candidiasis in immunocompromised Balb/c mice. Pretreatment with liposomised tuftsin prior to C. albicans infection clearly enhanced protection against candidiasis, suggesting a prophylactic role of tuftsin in normal and temporarily neutropenic animals. [source]

Generation of cortactin floxed mice and cellular analysis of motility in fibroblasts

GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 9 2009
Shinji Tanaka
Abstract Cortactin is an F-actin binding protein that has been suggested to play key roles in various cellular functions. Here, we generated mice carrying floxed alleles of the cortactin (Cttn) gene (Cttnflox/flox mice). Expression of Cre recombinase in mouse embryonic fibroblasts (MEFs) isolated from Cttnflox/flox embryos depleted cortactin within days, without disturbing F-actin distribution and localization of multiple actin-binding proteins. Cre-mediated deletion of Cttn also did not affect cell migration. To obtain mice with a Cttn null allele, we next crossed Cttnflox/flox mice with transgenic mice that express Cre recombinase ubiquitously. Western blot and immunocytochemical analysis confirmed complete elimination of cortactin expression in MEFs carrying homozygously Cttn null alleles. However, we found no marked alteration of F-actin organization and cell migration in Cttn null-MEFs. Thus, our results indicate that depletion of cortactin in MEFs does not profoundly influence actin-dependent cell motility. genesis 47:638,646, 2009. © 2009 Wiley-Liss, Inc. [source]

Surgical treatment of migraine headaches.

HEADACHE, Issue 3 2003
B Guyuron
Plast Reconstr Surg. 2002 Jun;109(7):2183-2189 This prospective study was conducted to investigate the role of removal of corrugator supercilii muscles, transection of the zygomaticotemporal branch of the trigeminal nerve, and temple soft-tissue repositioning in the treatment of migraine headaches. Using the criteria set forth by the International Headache Society, the research team's neurologist evaluated patients with moderate to severe migraine headaches, to confirm the diagnosis. Subsequently, the patients completed a comprehensive migraine headaches questionnaire and the team's plastic surgeon injected 25 units of botulinum toxin type A (Botox) into each corrugator supercilii muscle. The patients were asked to maintain an accurate diary of their migraine headaches and to complete a monthly questionnaire documenting pertinent information related to their headaches. Patients in whom the injection of Botox resulted in complete elimination of the migraine headaches then underwent resection of the corrugator supercilii muscles. Those who experienced only significant improvement underwent transection of the zygomaticotemporal branch of the trigeminal nerve with repositioning of the temple soft tissues, in addition to removal of the corrugator supercilii muscles. Once again, patients kept a detailed postoperative record of their headaches. Of the 29 patients included in the study, 24 were women and five were men, with an average age of 44.9 years (range, 24 to 63 years). Twenty-four of 29 patients (82.8 percent, p < 0.001) reported a positive response to the injection of Botox, 16 (55.2 percent, p < 0.001) observed complete elimination, eight (27.6 percent, p < 0.04) experienced significant improvement (at least 50 percent reduction in intensity or severity), and five (17.2 percent, not significant) did not notice a change in their migraine headaches. Twenty-two of the 24 patients who had a favorable response to the injection of Botox underwent surgery, and 21 (95.5 percent, p < 0.001) observed a postoperative improvement. Ten patients (45.5 percent, p < 0.01) reported elimination of migraine headaches and 11 patients (50.0 percent, p < 0.004) noted a considerable improvement. For the entire surgical group, the average intensity of the migraine headaches reduced from 8.9 to 4.1 on an analogue scale of 1 to 10, and the frequency of migraine headaches changed from an average of 5.2 per month to an average of 0.8 per month. For the group who only experienced an improvement, the intensity fell from 9.0 to 7.5 and the frequency was reduced from 5.6 to 1.0 per month. Only one patient (4.5 percent, not significant) did not notice any change. The follow-up ranged from 222 to 494 days, the average being 347 days. In conclusion, this study confirms the value of surgical treatment of migraine headaches, inasmuch as 21 of 22 patients benefited significantly from the surgery. It is also evident that injection of Botox is an extremely reliable predictor of surgical outcome. Comment: Many small placebo-controlled studies and much anecdotal literature suggests that botulinum toxin may be effective in prevention of migraine, perhaps to the same extent as conventional prophylactic treatment. Larger, randomized clinical trials are underway to resolve this issue. In the meantime, those who believe in the effectiveness of botulinum toxin prophylaxis argue about how it works, that is whether its antinociceptive properties are due to peripheral effects, central or presynaptic effects, or both. Dr. Guyuron's group favors the idea that botulinum toxin interrupts a reflex arc between the central nervous system (CNS) and peripheral musculature, and that after establishing efficacy by low dose botulinum injection in the corrugator supercilii muscles, surgical resection of these muscles results in prolonged and effective prophylaxis. The idea is radical but intriguing and should not be dismissed out of hand. However, a trial is necessary in which both the botulinum toxin injections are blinded with vehicle, and the study of the surgery involves a sham surgery control group with extended long-term follow-up, before these forms of prophylaxis can be recommended to patients. SJT [source]

Genomic analysis of Barrett's esophagus after ablative therapy: Persistence of genetic alterations at tumor suppressor loci

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2006
Mariska Hage
Abstract Barrett's esophagus (BE) is a major predisposing factor for the development of esophageal adenocarcinoma. Current strategies for treatment of BE, both dysplastic and nondysplastic, include photodynamic therapy (PDT) and argon plasma coagulation (APC). However, the effect of ablative therapy at the genetic level is unclear. We performed loss of heterozygosity (LOH) analysis of BE in baseline and follow-up biopsy specimens from 21 patients with BE (17 male, 4 female) treated with PDT and/or APC. At baseline, 14 patients had intestinal metaplasia without dysplasia (MET), 4 low-grade dysplasia (LGD) and 3 high-grade dysplasia (HGD). LOH was assessed using a panel of 9 polymorphic markers for evaluation of the P53 gene on 17p, P16 on 9p, DCC and SMAD4 on 18q and the APC gene on 5q. The tissue specimens obtained at baseline (t = 0) were analysed, as well as the first (t = 1; mean interval: 4 months) and last (t = 2; mean interval: 8 months) available biopsy with residual or recurrent BE after ablation. At t = 0, allelic loss was detected of 5q in 27%, 9p in 56%, 17p in 31% and 18q in 6% of informative cases. At t = 1 (18 patients with persistent MET and 3 with LGD) and at t = 2 (8 MET, 2 LGD), the LOH patterns were not statistically different from t = 0. Further, multiple genetic lineages before and after therapy were detected in 15 cases illustrating the multiclonal nature of BE. We conclude that recurrent and/or persistent BE after ablative therapy still contains genetic alterations associated with malignant progression to cancer. Therefore, the goal of treatment should be the complete elimination of Barrett's mucosa. © 2005 Wiley-Liss, Inc. [source]

Diclofenac removal from water by ozone and photolytic TiO2 catalysed processes

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2010
Juan F. García-Araya
Abstract BACKGROUND: The aim of this work was to establish the efficiency of single ozonation at different pH levels (5, 7 and 9) and with different TiO2 photolytic oxidizing systems (O2/UV-A/TiO2, O3/UV-A/TiO2 or UV-A/TiO2) for diclofenac removal from water, with especial emphasis on mineralization of the organic matter. RESULTS: In the case of single ozonation processes, results show fast and practically complete elimination of diclofenac, with little differences in removal rates that depend on pH and buffering conditions. In contrast, total organic carbon (TOC) removal rates are slow and mineralization degree reaches 50% at best. As far as photocatalytic processes are concerned, diclofenac is completely removed from the aqueous solutions at high rates. However, unlike single ozonation processes, TOC removal can reach 80%. CONCLUSION: In single ozonation processes, direct ozone reaction is mainly responsible for diclofenac elimination. Once diclofenac has disappeared, its by-products are removed by reaction with hydroxyl radicals formed in the ozone decomposition and also from the reaction of diclofenac with ozone. In the photocatalytic processes hydroxyl radicals are responsible oxidant species of diclofenac removal as well as by-products. Copyright © 2010 Society of Chemical Industry [source]

Purification of Aspergillus carbonarius polygalacturonase using polymeric membranes

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2008
E. Nakkeeran
Abstract BACKGROUND: Microfiltration (MF: 70,450 nm) and ultrafiltration (UF: 10,500 kDa) membranes were used to eliminate carbohydrates and other non-protein impurities from Aspergillus carbonarius culture broth containing polygalacturonase enzyme (EC 3.2.1.15) that would otherwise interfere with the purification processes and lead to enzyme loss. Further, diafiltration was attempted to improve the elimination of impurities as well as recovery of enzymes. RESULTS: MF resulted in removal of 2,25% carbohydrates with an enzyme recovery of 69,82% from the crude culture broth owing to the secondary layer formation. UF with 10 kDa membrane eliminated most of the carbohydrates (96%), phosphate salts and total acids with a recovery of 96% polygalacturonase and resulted in greater productivity. Using the above procedure, the enzyme was concentrated nearly 10-fold while the purity improved from 4.6 to 49.4 U mg,1 of dry matter. CONCLUSIONS: The results of this study focused on the elimination of carbohydrates and other non-protein impurities showed that UF could be used efficiently as a primary purification step during downstream processing of microbial culture broths containing enzymes. The present approach will ensure complete elimination of non-protein impurities thereby reducing the losses and difficulties in the subsequent purification steps. Copyright © 2008 Society of Chemical Industry [source]

Numerical Analysis of Heat Transfer during Surface Pasteurization of Hot Dogs with Vacuum-Steam-Vacuum Technology

JOURNAL OF FOOD SCIENCE, Issue 9 2004
L. Huang
ABSTRACT: The objective of this study was to validate the fundamental heat-transfer mechanism governing the process of vacuum-steam-vacuum surface pasteurization of hot dogs. It was hypothesized that the steam could not directly flow into the pores below the surface of hot dogs, and the heat was transferred into these areas by conduction. A numerical analysis program was first developed to estimate the heat-transfer coefficient between steam and hot dogs and was then used to simulate the temperature distribution at different locations below the surface. The hypothesis and computer simulation model were successfully validated using hot dogs surface-inoculated with Listeria innocua. Results showed that the heat from saturated steam must be conducted into the interior to kill L. innocua harboring in the pores and irregularities below the surface of hot dogs. Results of computer simulation and biological validation also suggested that heating must be maintained at 138 °C for at least 25 s to achieve a complete elimination (> 8 log colony-forming units per gram) of L. innocua from hot dogs. [source]

Influence of protrusive tooth contact on tapping point distribution

JOURNAL OF ORAL REHABILITATION, Issue 11 2000
T. Ueno
This study investigated the influence of protrusive tooth contacts (tooth contacts during mandibular protrusion) on the tapping point distribution. Nine healthy subjects volunteered for this study and the protrusive tooth contact pattern, as well as the retrusive tooth contact pattern, was altered on four maxillary occlusal splints. The first splint was adjusted to make the sagittal incisal path of protrusion and retrusion equivalent to that of the natural dentition. The second and third splints had partial and complete elimination of the protrusive tooth contact, respectively. The fourth splint had complete elimination of both protrusive and retrusive tooth contacts. The subjects were asked to use each splint continuously for 1 week. The tapping point distribution was measured on the 7th day after insertion of each splint. The four experimental occlusal conditions were found to have a significant effect on the tapping point distribution. The complete elimination of the protrusive tooth contact caused an anterior tapping point location and an increase in the tapping point area. The former tendency was found to be independent of the presence of the retrusive tooth contact. In conclusion, it was suggested that the protrusive tooth contact plays a significant role in maintaining the consistency and stability of the tapping point. [source]

Reconstructing and predicting the hepatitis C virus epidemic in Greece: increasing trends of cirrhosis and hepatocellular carcinoma despite the decline in incidence of HCV infection

JOURNAL OF VIRAL HEPATITIS, Issue 4 2004
V. Sypsa
Summary., In this study, a comprehensive methodology for modelling the hepatitis C virus (HCV) epidemic is proposed to predict the future disease burden and assess whether the recent decline in the incidence of HCV may affect the future occurrence of cirrhosis and hepatocellular carcinoma (HCC) cases. Using the prevalence of HCV, the distribution of chronic hepatitis C (CHC) patients within the various transmission groups and their infection-onset times, it was possible to reconstruct the incident infections per year in the past that progressed to CHC in Greece. The natural history of the disease was simulated in subcohorts of newly infected subjects using transition probabilities derived either empirically between fibrosis stages 0,4 or from literature review. Annual estimates of the incidence and prevalence of CHC by fibrosis stage, HCC and mortality in Greece were obtained up to 2030. HCV incidence peaked in the late 1980s at five new infections/10 000 person-years. Under the assumption of 20,100% decline in HCV incidence after 1990, the cumulative number of incident cirrhosis and HCC cases from 2002,2030 was projected to be lower by 9.6,48.2% and 5.9,29.5%, respectively, than that estimated under the assumption of no decline. However, the prevalent cirrhotic/HCC cases and HCV-related deaths are predicted to decline in the next 30 years only under the assumption of complete elimination of new HCV infections after 1990. Despite the progress in the reduction of HCV transmission, primary prevention does not seem adequate to reverse the rise in the incidence of cirrhosis and HCC. [source]

Inactivation of Cronobacter spp. (Enterobacter sakazakii) in infant formula using lactic acid, copper sulfate and monolaurin

LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2010
M.A. Al-Holy
Abstract Aims:, To investigate the effect of lactic acid (LA), copper (II), and monolaurin as natural antimicrobials against Cronobacter in infant formula. Methods and Results:, The effect of LA (0·1, 0·2 and 0·3% v/v), copper (II) (10, 50 and 100 ,g ml,1) and monolaurin (1000, 2000, and 3000 ,g ml,1) suspended into tween-80Ô or dissolved in ethanol against Cronobacter in infant formula was investigated. Reconstituted infant formula and powdered infant formula were inoculated with five strains of Cronobacter spp. at the levels of c. 1 × 106 CFU ml,1 and 1 × 103 CFU g,1, respectively. LA at 0·2% v/v had a bacteriostatic effect on Cronobacter growth, whereas 0·3% v/v LA resulted in c. 3 log10 reduction. Copper (II) at the levels of 50 ,g ml,1 and 100 ,g ml,1 elicited c. 1 and 2 log10 reductions, respectively. The combination of 0·2% LA and 50 ,g ml,1 copper (II) resulted in a complete elimination of the organism. Monolaurin exhibited a slight inhibitory activity against Cronobacter (c. 1·5 log10 difference) compared to the control when ethanol was used to deliver monolaurin. Conclusions:, A complete elimination of Cronobacter was obtained when a combination of sublethal concentrations of LA (0·2%) and copper (II) (50 ,g ml,1) was used. Significance and Impact of the Study:, The use of the synergistic interactive combination of LA and copper (II) could be beneficial to control Cronobacter in the infant formula industry. [source]

Survival of Salmonella hadar after washing disinfection of minimally processed spinach

LETTERS IN APPLIED MICROBIOLOGY, Issue 2 2000
M.E. Pirovani
Washing disinfection with chlorine is widely used to reduce the initial microbiological load during the preparation of minimally processed vegetables. The effects of initial concentration of chlorine, time and the liquid volume:produce weight ratio on the reduction of Salmonella counts on inoculated spinach were evaluated using response surface methodology. Initial chlorine concentration, time and the interaction between them had a significant effect on reduction of Salmonella populations. However, the liquid volume:produce weight ratio did not have significant effects. The highest Salmonella reduction was around 1·2,1·4 log at 125 ppm during 8 min regardless of the water:produce ratio. According to the results, chlorination reduced Salmonella hadar population, but the complete elimination from the produce was not achieved. [source]

Safety and efficacy of a new extensively hydrolyzed formula for infants with cow's milk protein allergy

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 4 2008
B. Niggemann
Cow's milk protein allergy (CMPA) is best treated by complete elimination of cow's milk from the diet. For infants with CMPA who cannot be breast-fed, formulas based on extensively hydrolyzed proteins or on amino acids are the preferred substitutes for cow's milk-based formulas. In this study, we compared the tolerance and growth of infants with CMPA who were fed a new extensively hydrolyzed formula containing lactose (eHF) with those who were fed an amino acid formula (AAF). This was a prospective, multi-center, randomized, reference-controlled study. Seventy-seven infants <12 months old with suspected CMPA were enrolled. In 66 of these, CMPA was confirmed by oral challenge in a double-blind, placebo-controlled food challenge (DBPCFC) or by a medical history of severe allergic reaction to cow's milk and a positive skin prick test. These infants were then tested for their reaction to eHF and AAF in a DBPCFC. All infants tolerated both formulas and were randomized to receive either eHF (n = 34) or AAF (n = 32) for 180 days. Growth (weight, length, and head circumference) and tolerance [skin, gastro-intestinal, and respiratory tract symptoms of allergy] were evaluated after 30, 60, 90, and 180 days. There were no significant differences between the two groups in any of the growth measurements. Length and head circumference were similar to Euro-growth standards, but weight was slightly lower. Gastro-intestinal and respiratory tract symptoms of allergy were also similar in the two groups. However, whereas SCORAD scores for atopic dermatitis remained constant throughout the study in infants-fed eHF, there was a slight decrease in those fed AAF. Infants-fed eHF had significantly fewer incidents of vomiting than infants-fed AAF and a significantly higher frequency of soft stools. The new eHF is safe and well tolerated in infants diagnosed with CMPA. [source]

Molecular Mechanisms of Microtubular Organelle Assembly in Tetrahymena

THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2000
JACEK GAERTIG
ABSTRACT. Thanks to recent technological advances, the ciliate Tetrahymena thermophila has emerged as an attractive model organism for studies on the assembly of microtubular organelles in a single cell. Tetrahymena assembles 17 types of distinct microtubules, which are localix.ed in cilia, cell cortex, nuclei, and the endoplasm. These diverse microtubules have distinct morphologies, stabilities, and associations with specific Microtubule-Assoeiated Proteins. For example, kinesin-111, a microtubular motor protein, is required for assembly of cilia and is preferentially targeted to microtubules of actively assembled, immature cilia. It is unlikely that the unique properties of individual microtubules are derived from the utilization of diverse tubulin genes, because Tetrahymena expresses only a single isotype of ,-and two isotypes of ,-tubulin. However, Tetrahymena tubulins are modified secondarily by a host of post-translational mechanisms. Each microtubule organelle type displays a unique set of secondary tubulin modifications. The results of systematic in vivo mutational analyses of modification sites indicate a divergence in significance among post-translational mechanisms affecting either ,-or ,-tubulin. Both acetylation and polyglycylation of ,-tubulin are not essential and their complete elimination does not change the cell's phenotype in an appreciable way. However, the multiple polyglycylation sites on ,-tubulin are essential for survival, and their partial elimination dramatically affects cell motility, growth and morphology. Thus, both high-precision targeting of molecular motors to individual organelles as well as organelle-specific tubulin modifications contribute to the creation of diverse microtubules in a single cytoplasm of Tetrahymena. [source]

Fermentative production of l -glycerol 3-phosphate utilizing a Saccharomyces cerevisiae strain with an engineered glycerol biosynthetic pathway,

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2008
A. Popp
Abstract Interest in l -glycerol 3-phosphate (l -G3P) production via microbial fermentation is due to the compound's potential to replace the unstable substrate dihydroxyacetone phosphate (DHAP) in one-pot enzymatic carbohydrate syntheses. A Saccharomyces cerevisiae strain with deletions in both genes encoding specific l -G3Pases (GPP1 and GPP2) and multicopy overexpression of l -glycerol 3-phosphate dehydrogenase (GPD1) was studied via small-scale (100 mL) batch fermentations under quasi-anaerobic conditions. Intracellular accumulation of l -G3P reached extremely high levels (roughly 200 mM) but thereafter declined. Extracellular l -G3P was also detected and its concentration continuously increased throughout the fermentation, such that most of the total l -G3P was found outside the cells as fermentation concluded. Moreover, in spite of the complete elimination of specific l -G3Pase activity, the strain showed considerable glycerol formation suggesting unspecific dephosphorylation as a mechanism to relieve cells of intracellular l -G3P accumulation. Up-scaling the process employed fed-batch fermentation with repeated glucose feeding, plus an aerobic growth phase followed by an anaerobic product accumulation phase. This produced a final product titer of about 325 mg total l -G3P per liter of fermentation broth. Biotechnol. Bioeng. 2008;100: 497,505. © 2008 Wiley Periodicals, Inc. [source]

Metabolism of PER.C6TM cells cultivated under fed-batch conditions at low glucose and glutamine levels

BIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006
Luis Maranga
Abstract This is the first study to examine PER.C6TM cell glucose/energy and glutamine metabolism with fed-batch cultures at controlled low glutamine, low glucose, and simultaneous low glucose and low glutamine levels. PER.C6TM cell metabolism was investigated in serum-free suspension bioreactors at two-liter scale. Control of glucose and/or glutamine concentrations had a significant effect on cellular metabolism leading to an increased efficiency of nutrient utilization, altered byproduct synthesis, while having no effect on cell growth rate. Cultivating cells at a controlled glutamine concentration of 0.25 mM reduced qGln and q by approximately 30%, qAla 85%, and qNEAA 50%. The fed-batch control of glutamine also reduced the overall accumulation of ammonium ion by approximately 50% by minimizing the spontaneous chemical degradation of glutamine. No major impact upon glucose/energy metabolism was observed. Cultivating cells at a glucose concentration of 0.5 mM reduced qGlc about 50% and eliminated lactate accumulation. Cells exhibited a fully oxidative metabolism with Y of approximately 6 mol/mol. However, despite no increase in qGln, an increased ammonium ion accumulation and Y were also observed. Effective control of lactate and ammonium ion accumulation by PER.C6TM cells was achieved using fed-batch with simultaneously controlled glucose and glutamine. A fully oxidative glucose metabolism and a complete elimination of lactate production were obtained. The qGln value was again reduced and, despite an increased q compared with batch culture, ammonium ion levels were typically lower than corresponding ones in batch cultures, and the accumulation of non-essential amino acids (NEAA) was reduced about 50%. In conclusion, this study shows that PER.C6TM cell metabolism can be confined to a state with improved efficiencies of nutrient utilization by cultivating cells in fed-batch at millimolar controlled levels of glucose and glutamine. In addition, PER.C6TM cells fall into a minority category of mammalian cell lines for which glutamine plays a minor role in energy metabolism. © 2006 Wiley Periodicals, Inc. [source]

Treatment of severe valvular aortic stenosis and subvalvular discrete subaortic stenosis and septal hypertrophy with Percutaneous CoreValve Aortic Valve Implantation,

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 5 2010
Ariel Finkelstein MD
Abstract Background: Percutaneous Aortic Valve Implantation (PAVI) is a procedure gaining popularity and becoming more widely used for the treatment of patients with severe aortic stenosis who are at high risk for surgery. Here we show, for the first time, that a successful and complete elimination of both valvular and subvalvular pressure gradients can be achieved with a slight modification of the valve implantation technique. Methods and Results: A 91-year-old woman presented with shortness of breath at rest, effort angina, and pulmonary congestion. Echocardiography revealed calcified aortic stenosis with a peak gradient of 75 mm Hg accros the valve, and discrete subaortic stenosis (DSS) and marked hypertrophy of the basal septum with systolic anterior motion of the mitral valve (SAM). The intra ventricular gradient had a dynamic pattern across the DSS and the septal hypertrophy and measured 75 mm Hg. The total gradient across the left ventricular outflow (valvular and subvalvular) was 125 mmHg. PAVI with a 23 mm CoreValve was performed with an intentional lower positioning of the valve towards the LV outflow tract; so that the valve struts cover the subaortic membrane and part of the thickened basal septum. At the end of the procedure, the SAM disappeared, and the left ventricular ouflow was widely open. At 1 month follow up the patient was asymptomatic, no pressure gradient was measured between the LV apex and the aorta. Conclusions: This is the first report of successful treatment of severe valvular aortic stenosis and combined subvalvular aortic stenosis due to DSS and septal hypertrophy with SAM with percutaneous aortic valve implantation. © 2010 Wiley-Liss, Inc. [source]

Helicobacter pylori is invasive and it may be a facultative intracellular organism

CELLULAR MICROBIOLOGY, Issue 5 2007
Andre Dubois
Summary The pathogenicity of many bacteria colonizing the gastrointestinal tract often depends on their ability to gain access to cells that are normally non-phagocytic. Helicobacter pylori colonizes the stomach of over half the world population and is the main cause of peptic ulcer disease and gastric cancer. It is generally considered to be a non-invasive pathogen present only in the lumen of the stomach and attached to gastric epithelial cells although a number of in vivo and in vitro studies have demonstrated that H. pylori is in fact invasive. In addition, H. pylori can repopulate the extracellular environment after complete elimination of extracellular bacteria with gentamicin, suggesting it may be considered a facultative intracellular bacterium. This review examines the validity of these observations and describes the evidence suggesting that the intracellular presence of H. pylori plays a role in the induction of diseases, in immune evasion, and in life-long persistence of the bacterium in the stomach of a majority of humans. [source]

Innate immunity and biodefence vaccines

CELLULAR MICROBIOLOGY, Issue 11 2003
Nicholas M. Valiante
Summary Host defence in vertebrates is achieved by the integration of two distinct arms of the immune system: the innate and adaptive responses. The innate response acts early after infection (within minutes), detecting and responding to broad cues from invading pathogens. The adaptive response takes time (days to weeks) to become effective, but provides the fine antigenic specificity required for complete elimination of the pathogen and the generation of immunologic memory. Antigen-independent recognition of pathogens by the innate immune system leads to the rapid mobilization of immune effector and regulatory mechanisms that provide the host with three critical advantages: (i) initiating the immune response (both innate and adaptive) and providing the inflammatory and co-stimulatory context for antigen recognition; (ii) mounting a first line of defence, thereby holding the pathogen in check during the maturation of the adaptive response; and (iii) steering the adaptive immune system towards the cellular or humoral responses most effective against the particular infectious agent. The quest for safer and more effective vaccines and immune-based therapies has taken on a sudden urgency with the increased threat of bioterrorism. Only a handful of vaccines covering a small proportion of potential biowarfare agents are available for human use (e.g. anthrax and small pox) and these suffer from poor safety profiles. Therefore, next generation biodefence-related vaccines and therapies with improved safety and the capacity to induce more rapid, more potent and broader protection are needed. To this end, strategies to target both the innate and adaptive immune systems will be required. [source]