Lunes 28 de Enero 2008; 12:30 hrs.

Chimerism and Tolerance in a Recipient of a Deceased-Donor Liver Transplant

 

• Stephen I. Alexander, M.B., B.S., Neil Smith, M.B., B.S., et al. N Engl J Med. 2008 Jan 24;358(4):369-74

• Complete hematopoietic chimerism and tolerance of a liver allograft from a deceased male donor developed in a 9-year-old girl, with no evidence of graft-versus-host disease 17 months after transplantation. The tolerance was preceded by a period of severe hemolysis, reflecting partial chimerism that was refractory to standard therapies. The hemolysis resolved after the ...Más.

Lunes 28 de Enero 2008; 12:27 hrs.

Tolerance and Chimerism after Renal and Hematopoietic-Cell Transplantation

 

• Scandling JD, Busque S, Dejbakhsh-Jones S, et al. N Engl J Med. 2008 Jan 24;358(4):362-68.

• We describe a recipient of combined kidney and hematopoietic-cell transplants from an HLA-matched donor. A post-transplantation conditioning regimen of total lymphoid irradiation and antithymocyte globulin allowed engraftment of the donor's hematopoietic cells. The patient had persistent mixed chimerism, and the function of the kidney allograft has been normal for more than 28 months since discontinuation of all immunosuppressive drugs. Adverse events requiring hospitalization were limited to a 2-day episode of fever ...Más.

Lunes 28 de Enero 2008; 12:25 hrs.

HLA-Mismatched Renal Transplantation without Maintenance Immunosuppression

 

• Kawai T, Cosimi AB, Spitzer TR,et al. N Engl J Med. 2008 Jan 24;358(4):353-61.

• Five patients with end-stage renal disease received combined bone marrow and kidney transplants from HLA single-haplotype mismatched living related donors, with the use of a nonmyeloablative preparative regimen. Transient chimerism and reversible capillary leak syndrome developed in all recipients. Irreversible humoral rejection occurred in one patient. In the other four recipients, it was possible to discontinue all immunosuppressive therapy 9 to 14 months after the transplantation, and renal function has remained stable for 2.0 to 5.3 years since transplantation. The T cells from these four recipients, tested in vitro, showed ....Más.

Lunes 28 de Enero 2008; 12:00 hrs.

Campylobacter jejuni Survives within Epithelial Cells by Avoiding Delivery to Lysosomes

 

• Watson RO, Galán JE PLoS Pathogens Vol. 4, No. 1, e14 doi:10.1371/journal.ppat.0040014

• Campylobacter jejuni is one of the major causes of infectious diarrhea world-wide, although relatively little is know about its mechanisms of pathogenicity. This bacterium can gain entry into intestinal epithelial cells, which is thought to be important for its ability to persistently infect and cause disease. We found that C. jejuni is able to survive within intestinal epithelial cells. However, recovery of intracellular bacteria required pre-culturing under oxygen-limiting conditions, suggesting that C. jejuni undergoes significant physiological changes within the intracellular environment. We also found that in epithelial cells the C. jejuni–containing vacuole deviates from the canonical endocytic pathway immediately after a unique caveolae-dependent entry pathway, thus avoiding delivery into lysosomes. In contrast, in macrophages, C. jejuni is....Más.

Lunes 28 de Enero 2008; 11:45 hrs.

Role of ABO Secretor Status in Mucosal Innate Immunity and H. pylori Infection

 

• Lindén S, Mahdavi J, Semino-Mora C, Olsen C, Carlstedt I, et al. PLoS Pathogens Vol. 4, No. 1, e2 doi:10.1371/journal.ppat.0040002

• The fucosylated ABH antigens, which constitute the molecular basis for the ABO blood group system, are also expressed in salivary secretions and gastrointestinal epithelia in individuals of positive secretor status; however, the biological function of the ABO blood group system is unknown. Gastric mucosa biopsies of 41 Rhesus monkeys originating from Southern Asia were analyzed by immunohistochemistry. A majority of these animals were found to be of blood group B and weak-secretor phenotype (i.e., expressing both Lewis a and Lewis b antigens), which are also common in South Asian human populations. A selected group of ten monkeys was inoculated with Helicobacter pylori and studied for changes in gastric mucosal glycosylation during a 10-month period. We observed a loss in mucosal fucosylation and concurrent induction and time-dependent dynamics in gastric mucosal sialylation (carbohydrate marker of inflammation), which affect....Más.

Lunes 28 de Enero 2008; 11:20 hrs.

Exploration of Small RNAs

 

• Hideya Kawaji, Yoshihide Hayashizaki. PLoS Genetics Vol. 4, No. 1, e22 doi:10.1371/journal.pgen.0040022

  For several decades, only a limited number of noncoding RNAs, such as ribosomal and transfer RNA, have been studied in any depth. In recent years, additional species of noncoding RNAs have increasingly been discovered. Of these, small RNA species attract particular interest because of their essential roles in processes such as RNA silencing and modifications. Detailed analyses revealed several pathways associated with the function of small RNAs. Although these pathways show evolutional conservation, there are substantial differences. Advanced technologies to profile RNAs have accelerated the field further resulting in the discovery of an increasing number of novel species, suggesting that we are only just beginning to appreciate the complexity of small RNAs and their functions. Here, we review recent progress in novel small RNA exploration, including discovered small RNA species, their pathways, and devised technologies. .....Más.

Viernes 25 de Enero 2008; 11:55 hrs.

Immunohistochemical approaches to the diagnosis of undifferentiated malignant tumors.

• Wick MR. Ann Diagn Pathol. 2008 Feb;12(1):72-84.

  Undifferentiated malignant neoplasms are a daunting diagnostic problem for anatomical pathologists, calling for a tour de force in morphological skill, clinicopathologic correlation, and application of adjunctive laboratory studies. The most useful approach to these lesions begins with generic classification into 1 of 4 histologic categories: small round cell; spindle cell; large polygonal cell (epithelioid); and pleomorphic neoplasms. Once that step has been accomplished, one can systemically apply corresponding groups of antibody reagents in immunohistologic studies and interpret the results in an algorithmic fashion. This review presents the tumor .....Más.

Viernes 25 de Enero 2008; 11:33 hrs.

Inflammation and Prostate Cancer: A Future Target for Prevention and Therapy?

• David Stock , Patti A. Groome , D. Robert Siemens. Urologic Clinics of North America- 2008 February (Vol. 35, Issue 1, Pages 117-130, DOI: 10.1016/j.ucl.2007.09.006). Given its long natural history, prostate cancer has become an ideal model for the clinical and basic science study of neoplastic disease in distinct pathologic phases: tumor initiation, progression, invasion, and metastasis. Chronic or recurrent acute inflammation, a product of infectious agents or other sources, has potential promotional roles in each of these phases. Nonsteroidal anti-inflammatory drugs (NSAIDs), because of their ability to attenuate inflammation, as well as possibly direct anti-cancer properties associated with the inhibition of stromal cyclooxygenase-2, are potential candidates for clinical use in prostate cancer. Though epidemiologic evidence indicating a reduced risk of prostate cancer for NSAID users supports a chemoprotective benefit, observational assessment and clinical trials of these agents among large cohorts of prostate cancer patients are needed to determine their value in prostate cancer management......Más.

Viernes 25 de Enero 2008; 11:10 hrs.

Isocitrate Dehydrogenase of Helicobacter pylori Potentially Induces Humoral Immune Response in Subjects with Peptic Ulcer Disease and Gastritis

 

• Hussain MA, Naveed SA, Sechi LA, Ranjan S, Alvi A, et al. (2008). PLoS ONE 3(1): e1481 doi:10.1371/journal.pone.0001481. H. pylori causes gastritis and peptic ulcers and is a risk factor for the development of gastric carcinoma. Many of the proteins such as urease, porins, flagellins and toxins such as lipo-polysaccharides have been identified as potential virulence factors which induce proinflammatory reaction. We report immunogenic potentials of isocitrate dehydrogenase (ICD), an important.....Más.

Viernes 25 de Enero 2008; 11:00 hrs.

Molecular Studies in Treponema pallidum Evolution: Toward Clarity?

PLoS Neglected Tropical Diseases 2(1): e184 doi:10.1371/journal.pntd.0000184. Syphilis is the best known treponemal infection and the disease has captured the attention of well-known physicians and the imaginations of writers and artists. In contrast, the nonvenereal treponemal infections (yaws, bejel, and pinta) have been endemic in remote regions of Africa, Southeast Asia, and South America, and are thus less well-known in western culture. However, these endemic treponematoses were so prevalent that, between 1952 and 1964, the World Health Organization (WHO) undertook a massive eradication campaign in which over 300 million people in Africa, South America, Southeast Asia, the South Pacific islands, and the Middle East were examined and ~50 million were treated with penicillin. It is estimated that the burden of disease was reduced by...Más.

Miércoles 16 Enero 2008; 21:50 hrs.

Update on Avian Influenza A (H5N1) Virus Infection in Humans

The New England Journal of Medicine 2008; 358:261-273. The unprecedented epizootic of avian influenza A (H5N1) viruses among birds continues to cause human disease with high mortality and to pose the threat of a pandemic. This review updates a 2005 report1 and incorporates information recently published or presented at the Second World Health Organization (WHO) Consultation on Clinical Aspects of Human Infection with Avian Influenza A (H5N1) Virus. Más.

Miércoles 16 Enero 2008; 09:50 hrs.

Probiotic modulation of symbiotic gut microbial–host metabolic interactions in a humanized microbiome mouse model

Molecular Systems Biology 2008; 4:157. Nils Chr. Stenseth, Bakyt B. Atshabar, Mike Begon et al. The transgenomic metabolic effects of exposure to either Lactobacillus paracasei or Lactobacillus rhamnosus probiotics have been measured and mapped in humanized extended genome mice (germ-free mice colonized with human baby flora). Statistical analysis of the compartmental fluctuations in diverse metabolic compartments, including biofluids, tissue and cecal short-chain fatty acids (SCFAs) in relation to microbial population modulation generated a novel top-down systems biology view of the host response to Más.

Martes 15 Enero 2008; 22:22 hrs.

Plague: Past, Present, and Future

PLoS Medicine Vol. 5, No. 1, e3 doi:10.1371/journal.pmed.0050003 Nils Chr. Stenseth, Bakyt B. Atshabar, Mike Begon et al. Recent experience with SARS (severe acute respiratory syndrome) and avian flu shows that the public and political response to threats from new anthropozoonoses can be near-hysteria. This can readily make us forget more classical animal-borne diseases, such as plague. Más.

Martes 15 Enero 2008; 22:20 hrs.

Key Role for Clumping Factor B in Staphylococcus aureus Nasal Colonization of Humans

PLoS Medicine Vol. 5, No. 1, e17 doi:10.1371/journal.pmed.0050017 Heiman F. L. Wertheim, Evelyn Wals, Roos Choudhurry et al. Staphylococcus aureus permanently colonizes the vestibulum nasi of one-fifth of the human population, which is a risk factor for autoinfection. The precise mechanisms whereby S. aureus colonizes the nose are still unknown. The staphylococcal cell-wall protein clumping factor B (ClfB) promotes adhesion to squamous epithelial cells in vitro and might be a physiologically relevant colonization factor.Más.

Jueves 11 Enero 2008; 23:00 hrs.

Fiebre tifoidea: Emergencia, cúspide y declinación de una enfermedad infecciosa en Chile

Rev. chil. infectol. 2007:24;435-440. Enrique Laval R. y Catterina Ferreccio R.En este artículo se presenta la historia de la fiebre tifoidea (FT) en Chile desde su reconocimiento como entidad nosológica hasta su situación actual. De la historia destaca la confusión que hubo en Chile durante muchos años entre esta enfermedad y el tifus exantemático a pesar de que la fiebre tifoidea ya había sido individualizada y caracterizada en la primera mitad del siglo XIX en Europa. Esto se podría explicar porque.....Más.

Jueves 11 Enero 2008; 22:45 hrs.

Immunogenicity of a Tetravalent Meningococcal Glycoconjugate Vaccine in Infants

JAMA. 2008;299(2):173-184. Immunization with a meningococcal tetravalent (serogroup ACWY) glycoconjugate vaccine is recommended for all US adolescents. However, the currently licensed vaccine is poorly immunogenic in infancy, when the highest rates of disease are observed.....Más.

Miércoles 09 Enero 2008; 22:55 hrs.

A Potential New Pathway for Staphylococcus aureus Dissemination: The Silent Survival of S. aureus Phagocytosed by Human Monocyte-Derived Macrophages

PLoS ONE 3(1): e1409 doi:10.1371/journal.pone.0001409. Malgorzata Kubica, Krzysztof Guzik, Joanna Koziel, Miroslaw Zarebski,et al. Although considered to be an extracellular pathogen, Staphylococcus aureus is able to invade a variety of mammalian, non-professional phagocytes and can also survive engulfment by professional phagocytes such as neutrophils and monocytes. In both of these cell types S. aureus promptly escapes from the endosomes/phagosomes and proliferates within the cytoplasm, which quickly leads to host cell death. In this report we show that S. aureus interacted with human monocyte-derived macrophages in a very different way to those of other mammalian cells. Upon phagocytosis by macrophages, S. aureus persisted intracellularly in vacuoles for 3–4 days before escaping into the cytoplasm and causing host cell lysis. Until the point of host cell lysis the infected macrophages showed no signs of apoptosis or necrosis and were functional. They were able to eliminate intracellular staphylococci if prestimulated with....Más.

Miércoles 09 Enero 2008; 22:42 hrs.

Hydrocortisone Therapy for Patients with Septic Shock

Charles L. Sprung, M.D., Djillali Annane, M.D., Ph.D., Didier Keh, M.D., Rui Moreno, M.D., Ph.D., Mervyn Singer, M.D., F.R.C.P., Klaus Freivogel, Ph.D., Yoram G. Weiss, M.D., Julie Benbenishty, R.N., Armin Kalenka, M.D., Helmuth Forst, M.D., Ph.D., Pierre-Francois Laterre, M.D., Konrad Reinhart, M.D., Brian H. Cuthbertson, M.D., Didier Payen, M.D., Ph.D., Josef Briegel, M.D., Ph.D., for the CORTICUS Study Group The New England Journal of Medicine 2008; 358:111-124. Background: Hydrocortisone is widely used in patients with septic shock even though a survival benefit has been reported only in patients who remained hypotensive after fluid and vasopressor resuscitation and whose plasma cortisol levels did not rise appropriately after the administration of corticotropin.

Methods: In this multicenter, randomized, double-blind, placebo-controlled trial, we assigned 251 patients to receive 50 mg of intravenous hydrocortisone and 248 patients to receive placebo every 6 hours for 5 days; the dose was then tapered during a 6-day period. At 28 days, the primary outcome was death among patients who did not have a response to a corticotropin test.

Results: Of the 499 patients in the study, 233 (46.7%) did not have a response to corticotropin (125 in the hydrocortisone group and 108 in the placebo group). At 28 days, there was no significant difference in mortality between patients in the two study groups who did not have a response to corticotropin (39.2% in the hydrocortisone group and 36.1% in the placebo group, P=0.69) or between those who had a response to corticotropin (28.8% in the hydrocortisone group and 28.7% in the placebo group, P=1.00). At 28 days, 86 of 251 patients in the hydrocortisone group (34.3%) and 78 of 248 patients in the placebo group (31.5%) had died (P=0.51). In the hydrocortisone group, shock was reversed more quickly than in the placebo group. However, there were more episodes of superinfection, including new sepsis and septic shock.

Conclusions: Hydrocortisone did not improve survival or reversal of shock in patients with septic shock, either overall or in patients who did not have a response to corticotropin, although hydrocortisone hastened reversal of shock in patients in whom shock was reversed. (ClinicalTrials.gov number, NCT00147004 [ClinicalTrials.gov] .) Más.

Miércoles 09 Enero 2008; 09:41 hrs.

Smallpox Vaccine Alternative Identifieds

ScienceDaily (Jan. 9, 2008) — University of California, Irvine infectious disease researchers have shown the effectiveness of a potential alternative to the existing smallpox vaccine that can replace the current biodefense stockpile for this lethal virus.Más.

Miércoles 09 Enero 2008; 09:30 hrs.

Celiac Disease: Discovery Of Enzyme's Structure May Lead To New Treatments

ScienceDaily (Jan. 9, 2008) — Researchers have discovered a new structure for a key enzyme associated with celiac disease, a finding that could lead to the design of new medications for the common digestive disorder, according to an article scheduled for the Jan. 7 issue of Chemical & Engineering News.Más.

Martes 08 Enero 2008; 09:56 hrs.

Genetic Background of Celiac Disease and Its Clinical Implications

Victorien M. Wolters, M.D.  and Cisca Wijmenga, Ph.D. Am J Gastroenterol 2007;102:1–6 Celiac disease (CD) is a complex genetic disorder with multiple contributing genes. Linkage studies have identified several genomic regions that probably contain CD susceptibility genes. The most important genetic factors identified are HLA-DQ2 and HLA-DQ8, which are necessary but not sufficient to predispose to CD. The associations found in non-HLA genomewide linkage and association studies are much weaker. This might be because a large number of non-HLA genes contributes to the pathogenesis of CD. Hence, the contribution of a single predisposing non-HLA gene might be quite modest. Practically all CD patients carry HLA-DQ2 or HLA-DQ8, while the absence of these molecules has a negative predictive value for CD close to 100%. Genetic risk profiles for CD would be helpful in clinical practice for predicting disease susceptibility and progression.Más.

Martes 08 Enero 2008; 09:40 hrs.

B-Cell Identity — Commitment Is Not Forever

Stephen L. Nutt, Ph.D.The New England Journal of Medicine 2008; 358:82-83. A general rule of cell biology is that once a cell commits to a particular differentiation pathway, there is no turning back. It is thought that the event triggering differentiation activates a distinct gene-expression program that is restricted by cell type; this program results in epigenetic changes in the DNA and in modification of accompanying proteins that locks in this state. Understanding cell-lineage commitment is important, because it lies at the heart of attempts to reprogram Más.

Martes 08 Enero 2008; 09:28 hrs.

Major Depressive Disorder

R.H. Belmaker, M.D., and Galila Agam, Ph.D. The New England Journal of Medicine 2008; 358:55-68. Depression is related to the normal emotions of sadness and bereavement, but it does not remit when the external cause of these emotions dissipates, and it is disproportionate to their cause. Classic severe states of depression often have no external precipitating cause. It is difficult, however, to draw clear distinctions between depressions.... Más.

Lunes 07 Enero 2008; 23:25 hrs.

Crohn Disease: Gene Decreases Intestinal Inflammation

ScienceDaily (Jan. 7, 2008) — There are two major types of inflammatory bowel disease (IBD), Crohn disease (CD) and ulcerative colitis (UC). Conflicting reports have indicated that the soluble factor IL-22 can have both IBD promoting and IBD controlling effects..... Más....or artcile: IL-22 ameliorates intestinal inflammation in a mouse model of ulcerative colitis. Journal of Clinical Investigation. January 3, 2008.

Lunes 07 Enero 2008; 23:04 hrs.

Contaminantes del volcán Llaima llegan hasta el océano Atlántico

(El Mercurio Online)

SANTIAGO.- La erupción del volcán Llaima el martes 1 de enero no sólo asustó a los habitantes de sus faldeos y concitó la atención internacional. Su fama de ser uno de los más activos de Chile llevó a la NASA - mediante su instrumento... Más

Lunes 07 Enero 2008; 23:00 hrs.

Is a universal flu vaccine on its way?

Late last week, a UK-based company reported promising safety data for a 'universal' flu vaccine. Heidi Ledford looks at how such vaccines work, and what challenges must still be overcome.... Más. (Published online 7 January 2008 | Nature | doi:10.1038/news.2008.410)