1,506 research outputs found
Human liver regeneration following massive hepatic necrosis: Two distinct patterns
Massive hepatic necrosis is a rare but often fatal complication of various liver injuries. Nevertheless, some patients can survive by spontaneous hepatic regeneration. It is known that surviving hepatocytes and/or progenitor cells can participate in this process but the mechanism of hepatic recovery is vague.We examined 13 explanted human livers removed for acute liver failure. Combined immunohistochemistry, digital image analysis, and three-dimensional reconstruction of serial sections were applied.Two patterns of regeneration could be distinguished. In livers with centrilobular necrosis, the surviving injured periportal hepatocytes started to proliferate and arrange into acinar structures and expressed α-fetoprotein. If the injury wiped out almost all hepatocytes, large areas of parenchymal loss were invaded by an intense ductular reaction. The cells at the distal pole of the ductules differentiated into hepatocytes and formed foci organized by the branches of the portal vein. The expanding foci often containing complete portal triads were arranged around surviving central veins. Their fusion eventually could be an attempt to re-establish the hepatic lobules.Regeneration of human livers following massive hepatic necrosis can occur in two ways-either through proliferation of α-fetoprotein-positive acinary-arranged hepatocytes or through ductular progenitor cells, with the latter being less efficient. Further investigation of these regenerative pathways may help identify biomarkers for likelihood of complete regeneration and hence have therapeutic implications
Objetos virtuais de aprendizagem: contribuições para o processo de aprendizagem em saúde e enfermagem
Predicting Myocardial Functional Recovery After Acute Myocardial Infarction: Relationship Between Myocardial Strain and Coronary Flow Reserve
Will availability of inhaled human insulin (Exubera®) improve management of type 2 diabetes? The design of the Real World trial
Immediate loading over lower prosthesis in edentulous mandibles: comparison between two types of prosthetic connection
Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli
Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts. Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins. Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets
Aortic stiffness as a marker of cardiac function and myocardial strain in patients undergoing aortic valve replacement
Background: Cardiac function and myocardial strain are affected by cardiac afterload, which is in part due to the
stiffness of the aortic wall. In this study, we hypothesize that aortic pulse wave velocity (PWV) as a marker of aortic
stiffness correlates with conventional clinical and biochemical markers of cardiac function and perioperative
myocardial strain in aortic valve replacement (AVR).
Methods: Patients undergoing AVR for aortic stenosis between June 2010 and August 2012 were recruited for
inclusion in this study. PWV, NYHA class and left ventricular (LV) function were assessed pre-operatively. PWV was
analysed both as a continuous and dichotomous variable according to age-standardized reference values. B-type
natriuretic peptide (BNP) was measured pre-operatively, and at 3 h and 18-24 h after cardiopulmonary bypass (CPB).
NYHA class, leg edema, and LV function were recorded at follow-up (409 ± 159 days).
Results: Fifty-six patients (16 females) with a mean age of 71 ± 8.4 years were included, with 50 (89%) patients
completing follow-up. The NYHA class of PWV-norm patients was significantly lower than PWV-high patients both
pre- and post-operatively. Multiple logistic regression also highlighted PWV-cut off as an independent predictor of
NYHA class pre- and post-operatively (OR 8.3, 95%CI [2.27,33.33] and OR 14.44, 95%CI [1.49,139.31] respectively). No
significant relationship was observed between PWV and either LV function or plasma BNP.
Conclusion: In patients undergoing AVR for aortic stenosis, PWV is independently related to pre- and post-operative
NYHA class but not to LV function or BNP. These findings provisionally support the use of perioperative PWV as a
non-invasive marker of clinical functional status, which when used in conjunction with biomarkers of myocardial strain
such as BNP, may provide a holistic functional assessment of patients undergoing aortic valve surgery. However, in
order for PWV assessment to be translated into clinical practice and utilised as more than simply a research tool, further
validation is required in the form of larger prospective studies specifically designed to assess the relationship between
PWV and these functional clinical outcomes
Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV
We present limits on anomalous WWZ and WW-gamma couplings from a search for
WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p
-> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron
Collider during the 1992-1995 run. The data sample corresponds to an integrated
luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling
parameters, the 95% CL limits on the CP-conserving couplings are
-0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a
form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also
presented.Comment: 11 pages, 2 figures, 2 table
Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics
We present a quasi-model-independent search for the physics responsible for
electroweak symmetry breaking. We define final states to be studied, and
construct a rule that identifies a set of relevant variables for any particular
final state. A new algorithm ("Sleuth") searches for regions of excess in those
variables and quantifies the significance of any detected excess. After
demonstrating the sensitivity of the method, we apply it to the semi-inclusive
channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV
at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no
evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review
Search For Heavy Pointlike Dirac Monopoles
We have searched for central production of a pair of photons with high
transverse energies in collisions at TeV using of data collected with the D\O detector at the Fermilab Tevatron in
1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could
rescatter pairs of nearly real photons into this final state via a box diagram.
We observe no excess of events above background, and set lower 95% C.L. limits
of on the mass of a spin 0, 1/2, or 1 Dirac
monopole.Comment: 12 pages, 4 figure
- …