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Kinds of Absence Terms modified by Absence Selected AbstractsABSENCE OF CORRELATION BETWEEN QRS DURATION AND ECHOGRAPHIC PARAMETERS OF VENTRICULAR DESYNCHRONIZATION.ECHOCARDIOGRAPHY, Issue 2 2004CAN WE STILL TRUST THE ELECTROCARDIOGRAPHIC CRITERIA? Background: Identification of the responder candidates for multisite pacing is still difficult and severe heart failure, dilated left ventricle with reduced ejection fraction, prolonged QRS with left bundle branch block (LBBB) are still considered the principal indicators of ventricular desynchronization. The aim of the study was to assess if echographic ventricular desynchronization parameters measured in patients with dilated cardiomyopathy and severe heart failure are correlated with the duration of the QRS on surface electrocardiogram. Methods: This study included 51 patients aged 58.8 ± 7.4 years with idiopathic DCM. The following parameters were measured: QRS duration; effective contraction time (ECT) measured as the interval between QRS onset and closure of aortic valve, interventricular delay (IVD) measured as the time between onset of aortic and pulmonary flow, left ventricular mechanical delay (LVD) as the time from maximal interventricular septum contraction and posterior wall contraction, posterior (P), lateral (L), and posterolateral (PL) wall delays, as the time from QRS onset to maximal wall contraction. Regional post-systolic contraction was defined in a given wall as the difference (contraction delay , ECT)> 50 ms. Results: 29 patients presented complete LBBB, 22 patients had QRS duration < 120 ms. 39 patients had a post-systolic contraction of the PL wall (32 patients of the L wall and 26 patients of the P wall). 16 patients with QRS duration <120 had a post-systolic contraction of the PL wall (as for the LBBB the rest of 39 patients). In 40 patients the sequence of regional ventricular contraction was: P-L-PL wall (16 patients with QRS < 120). LVD was > 100 ms in 36 patients (26 patients with LBBB and 10 with QRS < 120). 27 patients with LBBB and 6 with QRS < 120 ms presented IVD > 30 ms. There was no correlation between the QRS duration and the parameters listed above. Conclusions: In a population of patients with severe heart failure and dilated cardiomyopathy there is no correlation between the duration of the QRS and echocardiographic parameters of ventricular desynchronization. These results show that mechanical ventricular desynchronization can be observed in patients with a QRS duration < 120 ms. Further studies are needed to evaluate if this population could beneficiate of multisite pacing therapy. [source] SAVINGS IN THE ABSENCE OF FUNCTIONING PROPERTY RIGHTS1ECONOMIC AFFAIRS, Issue 1 2007Nick Silver Nigeria is a prime example of a developing country with ill-defined property rights. However, people still manage to save, mostly through traditional and informal means, facilitated by strong family and community institutions. This paper argues that the government should concentrate on strengthening these institutions rather than weakening them by imposing an inappropriate, Western-style, formal pensions system on the country. [source] THE ABSENCE OF EVIDENCE IS NOT THE SAME AS EVIDENCE FOR ABSENCE!ADDICTION, Issue 3 2008JØRGEN G. BRAMNESS No abstract is available for this article. [source] TERM STRUCTURES OF IMPLIED VOLATILITIES: ABSENCE OF ARBITRAGE AND EXISTENCE RESULTSMATHEMATICAL FINANCE, Issue 1 2008Martin Schweizer This paper studies modeling and existence issues for market models of stochastic implied volatility in a continuous-time framework with one stock, one bank account, and a family of European options for all maturities with a fixed payoff function h. We first characterize absence of arbitrage in terms of drift conditions for the forward implied volatilities corresponding to a general convex h. For the resulting infinite system of SDEs for the stock and all the forward implied volatilities, we then study the question of solvability and provide sufficient conditions for existence and uniqueness of a solution. We do this for two examples of h, namely, calls with a fixed strike and a fixed power of the terminal stock price, and we give explicit examples of volatility coefficients satisfying the required assumptions. [source] CONNECTIONS BETWEEN LOWER BACK PAIN, INTERVENTIONS, AND ABSENCE FROM WORK: A TIME-BASED META-ANALYSISPERSONNEL PSYCHOLOGY, Issue 3 2000JOSEPH J. MARTOCCHIO We conducted qualitative and quantitative reviews of the medical literature to develop an understanding of the linkages between nonspecific lower back pain (LBP) and employee absenteeism, and the efficacy of lower back pain interventions (LBPI) in reducing absenteeism. First, we offered a general time-based framework to clarify the causal flows between LBP and absence. Second, we inspected LBPIs designed to ameliorate LBP, which should, in turn, lead to reduced absence-taking. Third, we conducted a meta-analysis of 45 effect sizes involving 12,214 people, to examine the relationships between both LBP and LBPIs and absenteeism. Consistent with a presumption in the medical literature, we found support for the idea that chronic LBP has a positive overall relationship with absence-taking. The relationship was stronger for absence frequency measures than time lost measures. In addition, we found that increasing aggregation time (i.e., increases in the periods over which absence is observed) enhances the size of the chronic LBP-absence connection. Further, evidence showed that LBPIs were effective overall in reducing absenteeism. Finally, when there was a temporal mismatch between the form of LBP (acute vs. chronic) and the absenteeism aggregation period in LBPI studies, effect sizes were significantly smaller. We concluded with a discussion of these results, methodological limitations, and suggestions for future research that blends medical with organizational approaches to the etiology of absence. [source] CUT-THROAT FRINGE COMPETITION IN AN EMERGING COUNTRY MARKET: TAX EVASION OR THE ABSENCE OF MARKET POWER?,THE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 4 2009ALBERTO SALVO Brazil's established soft-drink firms recently lost ground to multiple low-price entrants, with small-scale operations and minimal advertising. While incumbents attributed such undercutting to entrants' lower costs from non-compliance with the law, ,generics' counterargued that incumbents' high prices stemmed from unilateral market power rather than cost heterogeneity. By estimating a structural model, I can single-handedly explain established brands' high prices through low equilibrium price elasticities of demand. Tax evasion in the fringe, while plausible, appears to be offset by higher procurement costs or less efficient scale. More generally, a competitive informal sector can alleviate the allocative distortions in certain concentrated industries. [source] A QUESTION OF ABSENCEBRITISH JOURNAL OF PSYCHOTHERAPY, Issue 3 2010Jackie Gerrard abstract This paper was written in an effort to process rather extreme countertransference reactions to an ,absent' patient, i.e. one who attended her twice-weekly psychotherapy only sporadically. At times she did not come for up to several months and consequently a serious debt would accrue. However, it was not so much the amount owing but rather the constant cancellations, with seemingly ,rational' excuses about her non-attendance that would provoke an intense frustration accompanied, at times, by furious, almost sadistic countertransference feelings. The patient kept her therapist ,dangling in uncertainty' (Brenman Pick, 2002), which the author considered to be a reflection of the patient's inner sado-masochistic object world. The author attempts to make sense of her countertransference in the light of the patient's early relationships and subsequently forms a hypothesis that the absences have been necessary to convey, very powerfully, experiences that may not have been communicated by regular attendance. Finally, the author offers her ,Afterthoughts' in the light of developments since the patient has read the paper and given her permission for publication. [source] Absence of tissue inhibitor of metalloproteinases 3 disrupts alveologenesis in the mouseDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 1 2009Sean E. Gill Tissue inhibitors of metalloproteinases (TIMPs) regulate extracellular matrix (ECM) degradation by matrix metalloproteinases (MMPs) throughout lung development. We examined lungs from TIMP3 null mice and found significant air space enlargement compared with wild type (WT) animals during a time course spanning early alveologenesis (post-partum days 1, 5, 9 and 14). Trichrome staining revealed a similar pattern of collagen distribution in the walls of nascent alveoli; however, the alveolar walls of TIMP3 mutant mice appeared to be thinner than controls. Assessment of MMP2 and MMP9 activities by gelatin zymography demonstrated a significant elevation in the active form of MMP2 at post-partum days 1 and 5. Treatment of null pregnant dams with a broad spectrum synthetic metalloproteinase inhibitor, GM6001, on embryonic day 16.5 enhanced the formation of primitive alveoli during the saccular stage of lung development as evidenced by a partial, but significant, rescue of alveolar size in post-partum day 1 animals. We propose that increased MMP activity in the absence of TIMP3 enhances ECM proteolysis, upsetting proper formation of primitive alveolar septa during the saccular stage of alveologenesis. Therefore, TIMP3 indirectly regulates alveolar formation in the mouse. To our knowledge, ours is the first study to demonstrate that in utero manipulation of the TIMP/MMP proteolytic axis, to specifically inhibit proteolysis, significantly affects lung development. [source] Identification of Tgf,1i4 as a downstream target of Foxc1DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2006Paula Sommer Craniofacial development is severely affected by null mutations in Foxc1, indicating a multifunctional role for Foxc1 in ocular, maxilla and mandible, skull and facial gland development. To delineate signaling pathways in which Foxc1 is involved we compared the transcriptomes of whole heads of Foxc1+/+ and Foxc1,/, embryos using a candidate cDNA array comprising genes expressed in the head mesenchyme and ocular region, and a 7K oligo array. Absence of Foxc1 led to downregulation of Stat1 and Galnt4, and upregulation of Tgf,1i4 at embryonic day 13.5 in the developing head mesenchyme. Comparative analyses revealed differences in the expression pattern of Tgf,1i4 in the head mesenchyme of Foxc1,/, and Foxc1+/+ embryos. In the ocular regions of Foxc1,/, embryos, Tgf,1i4 was expressed in higher levels in the conjunctival epithelium and in the condensing mesenchyme on the nasal aspect of the developing eye while in wild-type embryos more intense expression was seen in the mesenchyme on the temporal aspect of the eye. Such data indicate that Foxc1 regulation of Tgf,1i4 is complex and may be cell-type dependent. Analysis of the regulation of Tgf,1i4 by Foxc1 in a more homogenous cell population, mesenchymal cells isolated from the periocular region revealed that, in these cells, Foxc1 negatively regulated Tgf,1i4 expression, presumably via secreted factors such as TGF-,1. Since Foxc1 expression is essential for normal craniofacial development, it is possible that its downstream targets play a role in the development of the phenotypes associated with null mutations in Foxc1. [source] Absence of pestivirus antigen in brains with white matter damageDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2006Olaf Dammann We previously suggested that antenatal pestivirus infection might play a role in the pathogenesis of perinatal brain white matter damage (WMD) in preterm infants. We have now examined 22 brains from stillborns and deceased newborns (both preterm and term) for the presence of bovine virus diarrhoea virus (BVDV) antigen. The brains of five females and five males with WMD (median gestational age 36.5wks), and nine female and three male controls (median gestational age 36.5wks) were used in the study. No BVDV antigen was detected in any of the 22 brains. We conclude that brain infection with BVDV is unlikely to play a role in WMD pathogenesis among preterm or term newborns. Further research is needed to test the hypothesis that intrauterine exposure to pestivirus antigen elicits a fetal inflammatory response which then contributes to WMD. [source] Family history of suicidal behaviour: prevalence and significance in deliberate self-harm patientsACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2002Keith Hawton Objective:, To investigate whether there are differences between the characteristics of deliberate self-harm (DSH) patients with and without a family history of suicidal behaviour. Method:, In 146 DSH patients, those with and without a positive family history were compared with regard to the nature and repetition of their DSH episodes, and psychological and psychiatric characteristics. Results:, Fifty-two (35.6%) patients had a family history of suicidal behaviour. DSH was more frequent in patients' mothers (17.1%) than fathers (2.7%). Patients with a family history of suicidal behaviour, especially females, had higher state anger scores. Conclusion:, Family history of suicidal behaviour appears to be associated with greater anger. Absence of other associations suggests that family history probably has less implication for individuals who have already engaged in DSH than in contributing to its initiation. Future studies should include patients with violent or life-threatening DSH acts. [source] Absence of microfollicular basement membrane: A new indicator in the diagnosis of follicular carcinoma thyroidDIAGNOSTIC CYTOPATHOLOGY, Issue 7 2008Maheswar Sahoo M.D. Abstract The thyroid follicles represent a biological continuum. Each follicle is closely related to the follicle that is next to it. The important feature of a follicular carcinoma is a microfollicular pattern. We report a case of follicular carcinoma in a 48-year-old female that demonstrates microfollicles which are larger in size and contain more number of follicular cells in cytologic smears (20,29 cells) in contrary to the literature definition of microfollicles containing approximately 6,12 cells. We also demonstrate absence of basement membranes in these microfollicles in histologic sections by Silver Methanamine Stain, which may be an indicator to search for vascular and capsular invasion. This case report also describes postoperative positron emission tomography scan findings. Diagn. Cytopathol. 2008;36:519,522. © 2008 Wiley-Liss, Inc. [source] The wing vestiture of the non-ditrysian Lepidoptera (Insecta).ACTA ZOOLOGICA, Issue 4 2001Comparative morphology, phylogenetic implications Abstract The ultrastructure of the dorsal forewing vestiture in exemplars of all family group taxa of non-ditrysian Lepidoptera is examined, and the evolutionary implications at family level and above are discussed. Wing-scale terminology is reviewed. Three different types of bilayer wing-scale covering are recognized; only a few groups have a single-layer wing-scale covering. The general scale arrangement is random, but a few taxa have clustered scale arrangements and scattered heteroneurans have scales arranged in transverse rows. Cross ribs are present in all taxa, but only as vestiges in eriocraniid cover scales. Ridge dimorphism is widespread in Neolepidoptera. Surprisingly, ridges and cross ribs on the adwing scale surface are of general occurrence in Neopseustidae and Hepialidae, and are even found on parts of the ground scales of many other Neolepidoptera. Morphological evidence strongly indicates that the fused wing-scale types found in non-Coelolepidan Lepidoptera and Neolepidoptera are independently evolved, as evidenced from the presence of vestigial perforations. Absence of perforations is not infallible evidence that a scale is solid. Microtrichia are independently reduced in a number of taxa and probably re-evolved in at least higher nepticulids. Wing vestiture and scale characters indicate that Tischerioidea may be the sister group of Ditrysia. [source] The Incidence of Diastolic Right Atrial Collapse in Patients With Pleural Effusion in the Absence of Pericardial EffusionECHOCARDIOGRAPHY, Issue 3 2003Ara Sadaniantz The aim of this study was to describe the incidence of cardiac chamber collapse assessed by echocardiography and explore possible mechanisms in a clinical population of 116 patients with pleural effusion in the absence of pericardial effusion. We found that the frequency of chamber collapse was 18% in patients with pleural effusion in the absence of pericardial effusion, thus cardiac chamber collapse occurs in patients with pleural effusion. (ECHOCARDIOGRAPHY, Volume 20, April 2003) [source] Prosthetic Absence in Ben Jonson's Epicoene, The Alchemist, and Bartholmew FairENGLISH LITERARY RENAISSANCE, Issue 3 2007Mark Albert Johnston This essay interrogates the production of gender on the early modern English stage by considering what is at stake in the various (de)constructions of gender that occur in Ben Jonson's Jacobean city comedies Epicoene, or The Silent Woman, The Alchemist, and Bartholmew Fair. After analysing some contemporary medical constructions of hermaphrodism, the essay turns to the curious early modern preoccupation with transvestism and its implications about performances of masculinity and femininity. [source] Prognostic Factors Affecting Long-Term Retention of Topiramate in Patients with Chronic EpilepsyEPILEPSIA, Issue 3 2000S. D. Lhatoo Summary: Purpose: To determine the long-term retention rate of topiramate (TPM) therapy in patients with chronic epilepsy and to identify the relevant prognostic factors that influence retention. Methods: All patients with chronic epilepsy (n = 393) prescribed TPM between October 1, 1995, and December 31, 1998, at a tertiary referral centre for epilepsy were analysed. The retention rate for TPM was calculated by using Kaplan-Meier survival analysis, and the prognostic factors influencing retention were analysed by using Cox regression. Results: Of patients prescribed TPM, 30% continued taking the drug beyond 3 years. Discontinuation was mainly due to adverse events and lack of efficacy. Use of more than one new concurrent antiepileptic drug (AED) and lower maximal daily doses were more likely to result in treatment discontinuation due to adverse events. Older age at onset of epilepsy, a history of having previously taken more than one new AED [lamotrigine (LTG), gabapentin (GBP), or vigabatrin (VGB)], and lower maximal daily doses were more likely to lead to discontinuation due to lack of efficacy. Conclusions: A third of patients with chronic epilepsy started on TPM therapy will continue on treatment for >3 years. Absence of learning disabilities, late age at onset of seizures, previous use of more than one new AED, two or more concurrent AED use, and low maximal daily doses of TPM are more likely to result in discontinuation of medication. These factors should be taken into account when considering the use of TPM for the treatment of chronic epilepsy. [source] Persistence of Alarm-Call Behaviour in the Absence of Predators: A Comparison Between Wild and Captive-Born Meerkats (Suricata Suricatta)ETHOLOGY, Issue 11 2007Linda I. Hollén Performing correct anti-predator behaviour is crucial for prey to survive. But, are such abilities lost in species or populations living in predator-free environments? How individuals respond to the loss of predators has been shown to depend on factors such as the degree to which anti-predator behaviour relies on experience, the type of cues evoking the behaviour, the cost of expressing the behaviour and the number of generations under which relaxed selection has taken place. Here we investigated whether captive-born populations of meerkats (Suricata suricatta) used the same repertoire of alarm calls previously documented in wild populations and whether captive animals, as wild ones, could recognize potential predators through olfactory cues. We found that all alarm calls that have been documented in the wild also occurred in captivity and were given in broadly similar contexts. Furthermore, without prior experience of odours from predators, captive meerkats seemed to distinguish between faeces of potential predators (carnivores) and non-predators (herbivores). Despite slight structural differences, the alarm calls given in response to the faeces largely resembled those recorded in similar contexts in the wild. These results from captive populations suggest that direct, physical interaction with predators is not necessary for meerkats to perform correct anti-predator behaviour in terms of alarm-call usage and olfactory predator recognition. Such behaviour may have been retained in captivity because relatively little experience seems necessary for correct performance in the wild and/or because of the recency of relaxed selection on these populations. [source] The Effects of the Absence of Emergency Medicine Residents in an Academic Emergency DepartmentACADEMIC EMERGENCY MEDICINE, Issue 11 2002Daniel French MD Objective: What are the quality effects of an emergency medicine (EM) residency, and the associated 24/7 supervision of residents by faculty, in an academic emergency department (ED)? The authors evaluated activity and quality indicators when there were no EM residents present. The hypothesis of the study was that there was no difference between the patient care provided by faculty supervising EM residents and that with an alternative model without EM residents (AbsenceEMResident). Methods: To support the weekly residency educational program (Thursday), EM residents are not scheduled clinically for a 24-hour period (ConfDay). Emergency medicine resident coverage (mean 62.7 hours) was replaced with incremental faculty and mid-level providers (mean 41.0 hours). This study was limited to adult patients (22,527 visits of 39,190 ED total) for six months (January,June 2001) and compared indicators for ConfDay (n = 23) with all other days (NotConfDay, n = 158). Results: Comparing ConfDay (2,842 visits) with NotConfDay (19,685 visits), there was no difference in mean daily visits, inpatient admissions, intensive care unit admissions, or emergency medical services arrivals. ConfDay decision-to-admit time (333 vs. 313 min, p = 0.03) and length of stay for admissions (490 vs. 445 min, p = 0.000) were longer, with no difference for treat/release patients. There was no difference in the numbers of laboratory or radiology tests, consultations, unscheduled return visits, or patient satisfaction. Conclusion: During the study period, there was no measurable difference for most of the quality indicators studied. The AbsenceEMResident model is less efficient in admitting patients. Faculty supervision results in the same number of laboratory and radiology tests and consultations. Other specialties may consider this model if off-hours care becomes a concern. [source] Absence of veno-occlussive disease in a cohort of multiple myeloma patients undergoing autologous stem cell transplantation with targeted busulfan dosageEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2006A. Clopés Abstract:,Background:,Plasma concentrations of oral busulfan (BU) were measured in multiple myeloma (MM) patients undergoing autologous peripheral blood stem cell transplantation (ASCT) with a double alkylating conditioning protocol in order to individualise doses of BU based on individual pharmacokinetic parameters and to reduce toxicities related to BU exposure. Patients and methods:,Forty-four consecutive patients with MM participating in the co-operative Spanish protocol were prospectively evaluated. Conditioning regimen prior to autologous infusion consisted of BU followed by melphalan. BU pharmacokinetic parameters were estimated for each patient after the first dose based on measured concentrations and subsequent doses were modified as necessary to achieve target exposure. Results:,Mean BU exposure (AUCss) (±DS) before dosage modification range from 3192 to 12 180 ng h/mL. Twenty-six out of 44 (59%) patients required dose adjustment. None of the patients developed hepatic veno-occlusive disease (VOD). Grade , II oropharyngeal mucositis was observed in the majority of patients (95%) and the severity of mucositis increased with increasing average steady-state BU plasma concentration. There were four treatment-related deaths: two patients died from multiorgan failure and two of respiratory infections. Of the remaining 40 patients, 15 were in complete remission with negative immunofixation, 21 in partial remission and four in stable disease 3 months after ASCT. Conclusions:,The results of the present study show the variability in BU pharmacokinetic parameters and suggest the possible relationship between toxicities and BU exposure. Individualising BU dosage in MM patients undergoing ASCT we observed the absence of VOD. [source] Absence of p16 and p27 gene rearrangements and mutations in de novo myelodysplastic syndromesEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2005Sotirios G. Papageorgiou Abstract:, Myelodysplastic syndromes (MDS) represent a group of clonal hematopoietic disorders characterized by dyshemopoiesis and frequent evolution to acute leukemia. Tumor suppressor gene inactivation may be involved in MDS pathogenesis. The two families of cyclin-dependent kinase inhibitors (CDKIs) (INK4 family of p15, p16, p18 and p19 and CIP/KIP family of p21, p27 and p57) that negatively regulate cell cycle progression are known tumor suppressor genes. To determine whether genetic alterations of p16 and p27 genes play an important role in MDS pathogenesis, we examined DNA from 51 patients classified as 17 refractory anemias (RA), four refractory anemias with ringed sideroblasts (RARS), 19 refractory anemias with an excess of blasts (RAEB), 5 refractory anemias with excess of blasts in transformation (RAEB-t) and 6 chronic myelomonocytic leukemias (CMML). Southern blot analysis detected no homozygous deletions of p16 and p27. Polymerase chain reaction,single-strand conformation polymorphism (PCR,SSCP) and sequencing did not reveal point mutations for both genes with the exception of two allelic polymorphisms, namely a C , G transition at 447 bp of p16exon3 and a T , A transition at 791 bp of p27exon1 genes. Our results suggest that mutations of p16 and p27 genes resulting in abnormal p16 and p27 proteins do not represent a mechanism of gene inactivation involved in the pathogenesis of MDS. [source] Absence of phosphoglucose isomerase-1 in retinal photoreceptor, pigment epithelium and Muller cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004Simon N. Archer Abstract Macroarray analysis was used to compare equal amounts of cDNA from wild-type and rd/rd (retinal degeneration) mice, collected at P90 when photoreceptor degeneration is virtually complete. A stronger signal for the glycolytic enzyme phosphoglucose isomerase (Gpi1) was observed in the rd/rd sample. Extracellularly, Gpi1 may act as a cytokine, independently described as neuroleukin and autocrine motility factor. Retinal Gpi1 expression was investigated by Northern and Western blot analysis and immunohistochemistry. Double-labelling was performed with antibodies against Gpi1 and calbindin-D, glutamine synthetase, RPE65, calretinin and ultraviolet opsin in order to provide positive cell type identification. Northern and Western blots showed double expression levels per microgram of RNA and protein, respectively, in the rd/rd retina compared with wild-type. However, the total amount of Gpi1 protein per retina was indistinguishable. Gpi1 immunoreactivity was found in ganglion, amacrine, horizontal and bipolar cells, but not in rods, cones, pigment epithelium and Muller cells. This distribution explains why the absolute amounts of Gpi1 protein were not appreciably different between wild-type and the rd/rd phenotype, where rods and cones are absent, whilst the relative contribution of Gpi1 to the total protein and RNA pools differed. Some extracellular immunoreactivity was observed in the photoreceptor matrix around cones in freshly fixed tissue only, which could possibly reflect a role as a cytokine. We propose that glycolysis in Gpi1-negative cells proceeds entirely through the pentose phosphate pathway, creating NADPH at the cost of organic carbon. We hypothesize that the unique metabolic needs of photoreceptors justify this trade-off. [source] Absence of hematopoiesis from transplanted olfactory bulb neural stem cellsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2004María J. Yusta-Boyo Abstract Neural stem cells giving rise to neurons and glia cells have been isolated from the embryonic and adult central nervous system. The extent to which they are able to differentiate into cells of non-neural lineages, such as the hematopoietic lineage, is nonetheless unclear. We previously reported the isolation of stem cells from the mouse olfactory bulb neuroepithelium. In the present study, we analysed whether olfactory bulb stem cells (OBSC) can generate cells with hematopoietic features. Cells were prepared from the olfactory bulbs of transgenic mice expressing enhanced green fluorescent protein (EGFP). In culture, transgenic cells proliferated with the same kinetics as wild-type cells. Following mitogen removal, both cell types gave rise to similar numbers of neurons, astrocytes and oligodendrocytes, indicating that EGFP overexpression does not alter OBSC proliferation and differentiation patterns. When these cells were injected into the tail vein of irradiated mice, no hematopoietic cells derived from the OBSC could be recovered in their peripheral blood, spleen or bone marrow. By contrast, when OBSC were transplanted into the adult brain, EGFP-positive cells were found in the striatum and corpus callosum; differentiated cells expressed antigenic markers of neurons and astrocytes. These results suggest that embryonic olfactory bulb stem cells are not endowed with the potential to produce hematopoiesis. [source] Absence of lymphatic vessels in human dental pulp: a morphological studyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2010Renato Gerli Gerli R, Secciani I, Sozio F, Rossi A, Weber E, Lorenzini G. Absence of lymphatic vessels in human dental pulp: a morphological study. Eur J Oral Sci 2010; 118: 110,117. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci Few and controversial data are available in the literature regarding the presence of lymphatic vessels in the human dental pulp. The present study was designed to examine morphologically the existence of a lymph drainage system in human dental pulp. Human dental pulp and skin sections were immunohistochemically stained with specific antibodies for lymphatic endothelium (D2-40, LYVE-1, VEGFR-3 [vascular endothelial growth factor receptor-3], and Prox-1), with the pan-endothelial markers CD31 and von Willebrand factor (vWF), and with the blood-specific marker CD34. Several blood vessels were identified in human pulps and skin. Lymphatic vessels were found in all human skin samples but in none of the pulps examined. Western blotting performed on human dermis and on pulps treated with collagenase (to remove odontoblasts) confirmed these results. Transmission electron microscopy indicated that vessels which, by light microscopy, appeared to be initial lymphatic vessels had no anchoring filaments or discontinuous basement membrane, both of which are typical ultrastructural characteristics of lymphatic vessels. These results suggest that under normal conditions human dental pulp does not contain true lymphatic vessels. The various theories about dental pulp interstitial fluid circulation should be revised accordingly. [source] Comparison of Cyclodextrin-Dipeptide Inclusion Complexes in the Absence and Presence of Urea by Means of Capillary Electrophoresis, Nuclear Magnetic Resonance and Molecular ModelingEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2007Benjamin Waibel Abstract The use of capillary electrophoresis (CE) modified with cyclodextrin (CD) for the separation of stereoisomers of peptides is well established. To increase the solubility of ,-CD, urea is often added to the buffer which may influence the complexation of a CD with a guest molecule. The aim of the present study was to investigate the influence of urea on the complexation between dipeptides and ,-CD using Ala-Phe and Ala-Tyr as model compounds. For this purpose three different analytical methods were employed: capillary electrophoresis (CE), 1H-NMR spectroscopy and molecular dynamics simulations (MD). Electropherograms of the peptide enantiomers were different in the presence and absence of urea. For example, at pH,2.5 in the absence of urea the enantiomers of Ala-Tyr are not separated in contrast to the use of buffers containing urea. Applying "complexation-induced chemical shift (CICS)" in NMR spectroscopy and rotating frame Overhauser enhancement spectroscopy (ROESY) revealed differences in the complexation of the peptide enantiomers by ,-CD in the absence and presence of urea suggesting the stabilization of the complex through the phenolic hydroxyl group of tyrosine. MD simulations for different complexes were carried out with consideration of both water and urea molecules in solution. Simulations were performed for 1 ns. In conclusion, NMR spectroscopy and MD methods help to understand the structure of peptide-CD complexes and the separation and migration behavior in CE. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Palladium(II) Chloride and a (Dipyridin-2-ylmethyl)amine-Derived Palladium(II) Chloride Complex as Highly Efficient Catalysts for the Synthesis of Alkynes in Water or in NMP and of Diynes in the Absence of ReoxidantEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2005Juan Gil-Moltó Abstract The (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 and PdCl2 are efficient catalysts for cross-coupling reactions between terminal alkynes and aryl iodides or bromides under modified Sonogashira,Cassar,Heck conditions. The alkynylation can be performed under copper-free conditions in water at reflux or at room temperature under air with pyrrolidine as base and tetra- n -butylammonium bromide (TBAB) as additive, with TONs of up to 7,×,104 and TOFs(h,1) of up to 6666. Terminal alkynes can be arylated in NMP as well under copper- and amine-free conditions at 110 °C or room temperature, with tetra- n -butylammonium acetate (TBAA) acting as base with TONs up to 2,×,105 and TOFs (h,1) up to 66,666. In general, complex 1 displays a slightly higher efficiency than PdCl2 as catalyst and maintains the same activity after five consecutive runs. Alternatively, these alkynylation processes can be carried out under microwave heating conditions. The homocoupling of terminal alkynes to the corresponding 1,3-diynes proceeds under phosphane-free conditions with the (dipyridin-2-ylmethyl)amine-derived palladium chloride complex 1 or with PdCl2 as catalysts and with CuI as cocatalyst in NMP with use of either TBAA or pyrrolidine as bases. This Glaser-type reaction can be performed at 110 °C or at room temp. in the presence of air without the use of a reoxidant. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Presence of immunoreactive ,-endorphin in human skinEXPERIMENTAL DERMATOLOGY, Issue 5 2001M. Wintzen Abstract: The production and its induction by ultraviolet radiation (UVR) of proopiomelanocortin (POMC)-derived peptides by keratinocytes has been reported, albeit not consistently. Recently we demonstrated that only under specific culturing conditions human keratinocytes are capable of producing a ,-endorphin (,E)-like peptide with the characteristics of ,-lipotropin (,LPH). Here the presence and UV-induction of ,E-immunoreactivity (,E-IR) in keratinocytes in human skin in vivo was investigated. ,E-IR was detectable by immunohistochemistry in keratinocytes of the follicular matrix and to some extent in cells of sweat ducts, but was absent from epidermal keratinocytes. Absence of ,E-IR was confirmed by radioimmunoassay of HPLC-fractionated extracts of normal epidermis. Repeated exposure to solar-simulated UVR had no effect. This investigation is the first to demonstrate the presence of ,E-immunoreactive material in the follicular matrix of corporal hairs and in duct cells of sweat glands. The possible meaning of these results is discussed. [source] Absence of Gup1p in Saccharomyces cerevisiae results in defective cell wall composition, assembly, stability and morphologyFEMS YEAST RESEARCH, Issue 7 2006Célia Ferreira Abstract Saccharomyces cerevisiae Gup1p and its homologue Gup2p, members of the superfamily of membrane-bound O -acyl transferases, were previously associated with glycerol-mediated salt-stress recovery and glycerol symporter activity. Several other phenotypes suggested Gup1p involvement in processes connected with cell structure organization and biogenesis. The gup1, mutant is also thermosensitive and exhibits an altered plasma membrane lipid composition. The present work shows that the thermosensitivity is independent of glycerol production and retention. Furthermore, the mutant grows poorly on salt, ethanol and weak carboxylic acids, suggestive of a malfunctioning membrane potential. Additionally, gup1, is sensitive to cell wall-perturbing agents, such as Calcofluor white, Zymolyase, lyticase and sodium dodecyl sulphate and exhibits a sedimentation/aggregation phenotype. Quantitative analysis of cell wall components yielded increased contents of chitin and ,-1,3-glucans and lower amounts of mannoproteins. Consistently, scanning electron microscopy showed a strikingly rough surface morphology of the mutant cells. These results suggest that the gup1, is affected in cell wall assembly and stability, although the Slt2p/MAP kinase from the PKC pathway was phosphorylated during hypo-osmotic shock to a normal extent. Results emphasize the pleiotropic nature of gup1,, and are consistent with a role of Gulp1p in connection with several pathways for cell maintenance and construction/remodelling. [source] Absence of residual effects of a defeated resistance gene in poplarFOREST PATHOLOGY, Issue 2 2003K.-S. Woo Summary In a few plant pathosystems, defeated major genes have been shown to contribute to partial resistance to disease. This hypothesis has never been tested before in a forest tree, but pathogenic variation associated with recent hybridization in poplar rust in the Pacific northwest provided an opportunity. An F2 progeny of 256 poplar clones in the field near Corvallis, Oregon, USA, has been monitored for rust severity and infection type since the advent of the new hybrid rust, Melampsora × columbiana, in the mid-1990s. All 256 clones displayed a susceptible infection type in 1997 and again in 2000, and yet variation in uredinial density (i.e. partial resistance) was still observed. To determine which clones possessed a defeated resistance gene, a greenhouse inoculation was performed with an isolate of M. medusae, one of the parents of M. × columbiana. Clones that would have been resistant to M. medusae, prior to the advent of M. × columbiana, were thus identified. The inoculation resulted in a 1 : 1 segregation (,2=0.772; p=0.38) for resistance, indicating the presence of a major gene. However, the F2 clones possessing the defeated resistance gene displayed the same level of partial resistance in the field in both 1997 and 2000 as their full siblings lacking the gene. Résumé Chez quelques pathosystèmes végétaux, il a été montré que le contournement de gènes majeurs de résistance contribue à une résistance partielle envers la maladie. Cette hypothèse n'a encore jamais été testée chez un arbre forestier, mais le changement de pouvoir pathogène associéà l'hybridation récente de la rouille du peuplier dans le nord-ouest des USA en a fourni l'occasion. Une descendance F2 de 256 clones de peuplier a été suivie au champ près de Corvallis, Oregon, USA, pour la gravité de la rouille et le type d'infection, depuis l'apparition du nouvel hybride Melampsora x columbiana, dans les années 1990. Tous les 256 clones se sont montrés sensibles en 1997 et à nouveau en 2000, et une variation dans la densité des urédies (résistance partielle) a aussi été observée. Pour déterminer quels clones présentaient une résistance contournée, des inoculations ont été réalisées en serre avec un isolat de Melampsora medusae originaire du Kentucky. Des clones qui étaient résistants àM. medusae avant l'apparition de M. x columbiana ont ainsi été identifiés. Les inoculations ont abouti à une ségrégation 1 :1 (,2 = 0,772; P = 0,38) pour la résistance, ce qui indique la présence d'un gène majeur. Cependant, les clones F2 possédant le gène de résistance contourné montraient le même niveau de résistance partielle au champ en 1997 et 2000 que leurs plein-frères qui n'avaient pas ce gène. Zusammenfassung Für einige Pflanzen-Pathosysteme wurde gezeigt, dass unwirksam gewordene Haupt-Resistenzgene immer noch zu einer teilweisen Resistenz beitragen. Für Waldbäume wurde diese Hypothese bisher nie überprüft. Dies wurde jetzt im pazifischen Nordwesten möglich, wo der Pappelrost nach einem rezenten Hybridisierungsereignis stark variierte. An den F2-Nachkommenschaften von 256 Pappelklonen, die unter Freilandbedingungen in der Nähe von Corvallis, Oregon, USA wuchsen, wurde nach dem Auftreten des neuen Hybridrostes (Melampsora × columbiana) ab ca. 1990 die Krankheitsintensität und der Infektionstyp registriert. Alle 256 Klone zeigten einen anfälligen Infektionstyp im Jahre 1997 und dann wieder im Jahre 2000. Dabei wurde eine Variation in der Urediendichte (d.h. partielle Resistenz) beobachtet. Um zu bestimmen, welche Klone ein unwirksam gewordenes Resistenzgen besitzen, wurden Inokulationen im Gewächshaus mit einem Isolat von M. medusae, einem Elter von M. × columbiana, durchgeführt. Damit wurden Klone identifiziert, die vor dem Auftreten von M. × columbiana gegen M. medusae resistent waren. Der Infektionsversuch führte zu einer 1:1 Segregation (,2=0,772; P=0,38) für die Resistenz, was auf das Vorliegen eines Hauptgens hinweist. Die F2-Klone, welche dieses überwundene Resistenzgen besitzen, zeigten jedoch unter Feldbedingungen in den Jahren 1997 und 2000 den gleichen Grad einer Teilresistenz wie ihre Vollgeschwister, welchen dieses Gen fehlt. [source] The New Men's History and the Peculiar Absence of Gendered Power: Some Remedies from Early American Gender HistoryGENDER & HISTORY, Issue 1 2004Toby L. Ditz Historians with feminist commitments have expressed reservations about men's history and men's studies. This unease has existed more or less from the first appearance of men's history as a specialised area of inquiry, and shows no signs of abating. The first part of this article explores the sources of this unease. It discusses several guiding premises of men's history and shows that they tend to lead to the occlusion of men's gendered power over women. Nonetheless, the scrutiny of the gender of men is the logical outgrowth of several decades of theoretical and empirical work on gender,witness the many historians of women and gender who have recently turned their attention to the systematic study of manliness and masculinity. With the help of examples drawn from the scholarship on the history of the British colonies in America and the early United States, the second part of this article enumerates several strategies for successfully highlighting men's gendered power in histories of manliness and masculinity. [source] Absence of TGF, signaling in embryonic vascular smooth muscle leads to reduced lysyl oxidase expression, impaired elastogenesis, and aneurysmGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 2 2009Bibha Choudhary Abstract To address the requirement for TGF, signaling in the formation and maintenance of the vascular matrix, we employed lineage-specific mutation of the type II TGF, receptor gene (Tgfbr2) in vascular smooth muscle precursors in mice. In both neural crest- and mesoderm-derived smooth muscle, absence of TGF, receptor function resulted in a poorly organized vascular elastic matrix in late-stage embryos which was prone to dilation and aneurysm. This defect represents a failure to initiate formation of the elastic matrix, rather than a failure to maintain a preexisting matrix. In mutant tissue, lysyl oxidase expression was substantially reduced, which may contribute to the observed pathology. genesis 47:115,121, 2009. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||