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1.
Rev Sci Instrum ; 93(5): 053903, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35649806

RESUMO

The ability to visualize a sample undergoing a pressure-induced phase transition allows for the determination of kinetic parameters, such as the nucleation and growth rates of the high-pressure phase. For samples that are opaque to visible light (such as metallic systems), it is necessary to rely on x-ray imaging methods for sample visualization. Here, we present an experimental platform developed at beamline P02.2 at the PETRA III synchrotron radiation source, which is capable of performing simultaneous x-ray imaging and diffraction of samples that are dynamically compressed in piezo-driven diamond anvil cells. This setup utilizes a partially coherent monochromatic x-ray beam to perform lensless phase contrast imaging, which can be carried out using either a parallel- or focused-beam configuration. The capabilities of this platform are illustrated by experiments on dynamically compressed Ga and Ar. Melting and solidification were identified based on the observation of solid/liquid phase boundaries in the x-ray images and corresponding changes in the x-ray diffraction patterns collected during the transition, with significant edge enhancement observed in the x-ray images collected using the focused-beam. These results highlight the suitability of this technique for a variety of purposes, including melt curve determination.

2.
J Chem Phys ; 155(5): 054501, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34364334

RESUMO

The transformation of carbon monoxide (CO) from a molecular liquid to a polymeric solid under isothermal compression at room temperature is investigated using first principles theory. We report structural and thermodynamic properties from ambient density up to 2.45 g/cc obtained using density functional theory molecular dynamics simulations, including hybrid exchange corrections. The theoretical results are compared with newly obtained polymeric CO samples, synthesized in a large volume press. The explosive performance of polymeric CO is predicted and discussed. Under most favorable assumptions, it is found to be comparable to trinitrotoluene.

3.
World J Urol ; 39(9): 3441-3446, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33770242

RESUMO

INTRODUCTION: Transurethral resection of the prostate and open prostatectomy have been the standard of care for the surgical treatment of benign prostatic obstruction (BPO) over decades. New emerging techniques for the surgical management of BPO have been currently introduced, but might be associated with new, unusual complications. METHODS: We herewith report on two patients with a rectal perforation after aquablation treatment of BPO. RESULTS: In the first case, the diagnosis was made 2 days after the aquablation procedure due to unspecific postoperative symptoms. A complex combined open/endoscopic repair of the defect was carried out thereafter. As a consequence, a rectoscopy was routinely performed since then following each aquablation procedure. In the second case, intraoperative rectoscopy after uneventful aquablation revealed the rectal perforation. The perforation was clipped immediately with an over the scope-clip by colonoscopy. CONCLUSIONS: These two cases of a rectal perforation after aquablation of the prostate demonstrate an unusual complication and its complex management. Diagnostic delay complicates its treatment. Therefore, immediate rectoscopy should be performed routinely after the aquablation procedure.


Assuntos
Técnicas de Ablação/efeitos adversos , Perfuração Intestinal/etiologia , Complicações Intraoperatórias/etiologia , Complicações Pós-Operatórias/etiologia , Hiperplasia Prostática/cirurgia , Reto/lesões , Técnicas de Ablação/métodos , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Água
4.
Int J Oral Maxillofac Surg ; 49(1): 135-142, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31053519

RESUMO

The in vivo regeneration of bone flaps might be an alternative to autogenous bone grafting. The first human case of mandibular reconstruction using the greater omentum as a bioreactor was reported in 2016. However, whether engineered bone will support the osseointegration of dental implants has not yet been investigated. In this study, bone tissue engineering was performed in the greater omentum of nine miniature pigs using bone morphogenetic protein 2, bone marrow aspirate, and three different scaffolds: hydroxyapatite, biphasic calcium phosphate (BCP), and titanium. After 8 weeks, two implants were placed in each scaffold; after another 8 weeks, the bone blocks were harvested for radiographic, histological, and histomorphometric analysis. All implants exhibited sufficient primary stability, and the success rate was 100%. The bone-to-implant contact ratios (BICs) were 38.2%, 68.5%, and 42.9%; the inter-thread bone densities were 29.4%, 64.9%, and 33.5%; and the peri-implant bone-scaffold densities were 56.4%, 87.6%, and 68.6% in the hydroxyapatite, BCP, and titanium groups, respectively. The BIC showed a strong correlation (r = 0.76) with the peri-implant bone-scaffold density. This study shows that de novo engineered bone leads to successful osseointegration and therefore may allow implant-based prosthodontic rehabilitation.


Assuntos
Implantes Dentários , Osseointegração , Animais , Osso e Ossos , Implantação Dentária Endóssea , Planejamento de Prótese Dentária , Humanos , Propriedades de Superfície , Suínos , Engenharia Tecidual , Titânio
5.
Rev Sci Instrum ; 90(2): 023903, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30831719

RESUMO

Advanced Spectral Analysis Program is a LabVIEW-based program intended for rapid and accurate analysis of large sets of spectral data. It can handle a range of different types of data including angle-resolved and energy-dispersive powder diffraction and Raman spectra. We present it here with a focus on high-temperature high-pressure powder diffraction. The program contains a novel graphical user interface that allows rapid manual fitting and indexing of peaks which require precise fitting ranges and includes tools for fitting any Bravais lattice and arbitrary user-defined multivariate equations of state. The program allows the user to simultaneously view and manipulate multiple data sets from an experiment. The user can save and load analysis progress at any point, allowing for repeatable calculations to be performed, and to allow the fast comparison of different analysis parameters.

6.
Phys Rev Lett ; 122(6): 066401, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30822065

RESUMO

Using the satellite structure of the Lγ_{1} line in nonresonant x-ray emission spectra, we probe the high-pressure evolution of the bare 4f signature of the early light lanthanides at ambient temperature. For Ce and Pr the satellite peak experiences a sudden reduction concurrent with their respective volume collapse (VC) transitions. These new experimental results are supported by calculations using state-of-the-art extended atomic structure codes for Ce and Pr, and also for Nd, which does not exhibit a VC. Our work suggests that changes to the 4f occupation are more consistently associated with evolution of the satellite than is the reduction of the 4f moment. Indeed, we show that in the case of Ce, mixing of a higher atomic angular momentum state, driven by the increased hybridization, acts to obscure the expected satellite reduction. These measurements emphasize the importance of a unified study of a full set of microscopic observables to obtain the most discerning test of the underlying, fundamental f-electron phenomena at high pressures.

7.
Proc Nutr Soc ; 78(4): 484-495, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30816080

RESUMO

Knowing who eats what, understanding the various eating habits of different population groups, according to the geographical area, is critical to develop evidence-based policies for nutrition and food safety. The FAO/WHO Global Individual Food consumption data Tool (FAO/WHO GIFT) is a novel open-access online platform, hosted by FAO and supported by WHO, providing access to harmonised individual quantitative food consumption (IQFC) data, especially in low- and middle-income countries (LMIC). FAO/WHO GIFT is a growing repository, which will serve as the global FAO/WHO hub to disseminate IQFC microdata. Currently five datasets from LMIC are available for dissemination, and an additional fifty datasets will be made available by 2022. To facilitate the use of these data by policy makers, ready-to-use food-based indicators are provided for an overview of key data according to population segments and food groups. FAO/WHO GIFT also provides an inventory of existing IQFC data worldwide, which currently contains detailed information on 188 surveys conducted in seventy-two countries. In order for end-users to be able to aggregate the available data, all datasets are harmonised with the European Food Safety Authority's food classification and description system FoodEx2 (modified for global use). This harmonisation is aimed at enhancing the consistency and reliability of nutrient intake and dietary exposure assessments. FAO/WHO GIFT is developed in synergy with other global initiatives aimed at increasing the quality, availability and use of IQFC data in LMIC to enable evidence-based decision-making and policy development for better nutrition and food safety.


Assuntos
Bases de Dados Factuais , Inquéritos sobre Dietas , Ingestão de Energia/fisiologia , Ciências da Nutrição/organização & administração , Exposição Dietética , Ingestão de Alimentos/fisiologia , Inocuidade dos Alimentos , Humanos , Nações Unidas , Organização Mundial da Saúde
8.
Nat Commun ; 9(1): 3563, 2018 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-30177697

RESUMO

Static compression experiments over 4 Mbar are rare, yet critical for developing accurate fundamental physics and chemistry models, relevant to a range of topics including modeling planetary interiors. Here we show that focused ion beam crafted toroidal single-crystal diamond anvils with ~9.0 µm culets are capable of producing pressures over 5 Mbar. The toroidal surface prevents gasket outflow and provides a means to stabilize the central culet. We have reached a maximum pressure of ~6.15 Mbar using Re as in situ pressure marker, a pressure regime typically accessed only by double-stage diamond anvils and dynamic compression platforms. Optimizing single-crystal diamond anvil design is key for extending the pressure range over which studies can be performed in the diamond anvil cell.

9.
Rev Sci Instrum ; 89(12): 125117, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30599546

RESUMO

The measurement of transient temperatures less than 1000 K for samples in laser-heated diamond anvil cells remains a challenge. Here we present the design and performance characteristics of a multi-channel pyrometer that works in the near-infrared from 1200 to 2000 nm. It has a relatively small footprint, is portable, requires only low voltage power supplies, and can report temperatures down to 800 K on the millisecond scale or faster. A single data point without averaging can be acquired in 14 µs (sampling rate of 7 kilosamples per second). In conjunction with a diamond anvil cell, the system delivers accurate and rapid measurements down to ∼830 K. The pyrometer has been successfully interfaced several times with the combined x-ray diffraction and laser heating system at the High Pressure Collaborative Access Team at the Advanced Photon Source at Argonne National Laboratories.

10.
Chirurg ; 88(10): 841-847, 2017 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-28871350

RESUMO

BACKGROUND: Terrorist attacks have outreached to Europe with more and more attacks on civilians. Derived from war surgery experience and from lessons learned from major incidents, it seems mandatory for every surgeon to improve understanding of the special circumstances of trauma following a terrorist attack and its' management. METHOD: A short literature review is followed by outlining the damage control surgery (DCS) principle for each organ system with practical comments from the perspective of a specialized hepatobiliary (HPB) surgery unit. CONCLUSION: Every surgeon has to become familiar with the new entities of blast injuries and terrorist attack trauma. This concerns not only the medical treatment but also tailoring surgical treatment with a view to a lack of critical resources under these circumstances. For liver and pancreatic trauma, simple treatment strategies are a key to success.


Assuntos
Traumatismos por Explosões , Terrorismo , Traumatismos Torácicos , Traumatismos Abdominais , Traumatismos por Explosões/cirurgia , Serviço Hospitalar de Emergência , Europa (Continente) , Humanos , Escala de Gravidade do Ferimento , Fígado , Baço , Traumatismos Torácicos/cirurgia
11.
Z Gastroenterol ; 54(2): 152-4, 2016 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-26854835

RESUMO

INTRODUCTION: Chylous ascites with a simultaneously presenting acute appendicitis is a uncommon finding which has been rarely reported in present literature. CASE REPORT: We present the case of a 36 years old patient showing the clinical signs of an acute appendicitis with an intraoperative finding of chylous ascites. DISCUSSION: The causing factors for chylous ascites are numerous, the clinical manifestations nonspecific. Thus the adequate diagnostic measures vary. The therapy is mainly based on medicational and dietary treatment but also benefits from a surgical approach.


Assuntos
Apendicite/diagnóstico , Apendicite/terapia , Ascite Quilosa/diagnóstico , Ascite Quilosa/terapia , Adulto , Apendicite/complicações , Ascite Quilosa/complicações , Terapia Combinada/métodos , Diagnóstico Diferencial , Drenagem/métodos , Humanos , Laparoscopia/métodos , Masculino , Resultado do Tratamento
12.
Braz J Med Biol Res ; 49(2): e5001, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26648092

RESUMO

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.


Assuntos
Aloenxertos/fisiologia , Implante de Prótese Vascular/métodos , Prótese Vascular , Criopreservação/métodos , Crioprotetores , Liofilização/métodos , Glutaral , Artéria Pulmonar , Aloenxertos/anatomia & histologia , Aloenxertos/cirurgia , Análise de Variância , Animais , Pressão Sanguínea , Prótese Vascular/efeitos adversos , Cães , Feminino , Masculino , Artéria Pulmonar/patologia , Artéria Pulmonar/fisiologia , Circulação Pulmonar , Transplante Homólogo , Resistência Vascular
13.
Braz. j. med. biol. res ; 49(2): e5001, 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-766983

RESUMO

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.


Assuntos
Animais , Cães , Feminino , Masculino , Aloenxertos/fisiologia , Prótese Vascular , Implante de Prótese Vascular/métodos , Crioprotetores , Criopreservação/métodos , Liofilização/métodos , Glutaral , Artéria Pulmonar , Análise de Variância , Aloenxertos/anatomia & histologia , Aloenxertos/cirurgia , Pressão Sanguínea , Prótese Vascular/efeitos adversos , Circulação Pulmonar , Artéria Pulmonar/patologia , Artéria Pulmonar/fisiologia , Transplante Homólogo , Resistência Vascular
14.
Rev Sci Instrum ; 84(8): 083908, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24007080

RESUMO

We present design and performance details for a polycapillary-coupled x-ray spectrometer that provides very high collection efficiency at a moderate energy resolution suitable for many studies of nonresonant x-ray emission spectroscopy, especially for samples of heavy elements under high pressures. Using a single Bragg analyzer operating close to backscattering geometry so as to minimize the effect of the weak divergence of the quasicollimated exit beam from the polycapillary optic, this instrument can maintain a typical energy resolution of 5 eV over photon energies from 5 keV to 10 keV. We find dramatically improved count rates as compared to a traditional higher-resolution instrument based on a single spherically bent crystal analyzer.

15.
J Phys Condens Matter ; 25(34): 345401, 2013 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-23884010

RESUMO

The longitudinal and transverse sound speeds, cL and cT, of polycrystalline cerium were measured under pressure across the iso-structural γ-α phase transition at 0.75 GPa to beyond 3 GPa. In contrast to previous methods all quantities were directly obtained and no assumptions were made about the size of the volume collapse. Up to the transition our values for cL are in excellent agreement with previous ones, while our values for cT are significantly lower. We deduce values for the adiabatic bulk modulus BS, the shear modulus [Formula: see text], and the pressure dependent Debye temperature, ΘD(p). ΘD(p) is in good agreement with recent results derived from phonon dispersion measurements on single crystals. The ratio of the Debye temperature values bracketing the transition indicates a lattice contribution to the entropy change across the volume collapse, ΔSvib(γ â†’ α) ≈ (0.68 ± 0.06)kB, consistent with previous results obtained by neutron scattering, but significantly larger than other previously determined values.

16.
Phys Rev Lett ; 109(19): 195705, 2012 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-23215404

RESUMO

High-pressure x-ray emission measurements are used to provide crucial evidence in the longstanding debate over the nature of the isostructural (α, γ) volume collapse in elemental cerium. Extended local atomic model calculations show that the satellite of the Lγ emission line offers direct access to the total angular momentum observable (J(2)). This satellite experiences a 30% steplike decrease across the volume collapse, validating the Kondo model in conjunction with previous measurements. Direct comparisons are made with previous predictions by dynamical mean field theory. A general experimental methodology is demonstrated for analogous work on a wide range of strongly correlated f-electron systems.


Assuntos
Cério/química , Modelos Químicos , Transição de Fase , Teoria Quântica , Espectrometria por Raios X/métodos
17.
Cancer Gene Ther ; 19(12): 880-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23099886

RESUMO

The aim of this study was to evaluate the efficacy of the chemokine CCL19 (ELC) as an adjuvant for intradermal gene gun delivery of Her2/neu DNA and to investigate the role of B cells in CCL19-mediated enhancement of immune responses. Balb/c mice were immunized intramuscularly (i.m.) on days 1 and 15 with plasmid DNA (pDNA) (100 µg DNA) or intradermally (i.d.) by gene gun delivery (1-2 µg DNA). Administration of pDNA encoding Her2/neu (pDNA(Her2/neu) was compared with pDNA(Her2/neu) plus pDNA(CCL19), pDNA(CCL19), mock vector or uncoated gold particles/phosphate-buffered saline (PBS). Tumor challenge was performed subcutaneously on day 25 with syngeneic Her2/neu(+) tumor cells (D2F2/E2). Intradermal immunization by gene gun led to an enhancement of tumor protection by the DNA vaccine as compared with i.m. immunization. The protective effect of the vaccine was further enhanced by coadministration of pDNA(CCL19) both after i.m. and i.d. immunization. Tumor protection was associated with Her2/neu-specific T cell and humoral immune responses. Experiments in B-cell-deficient µMT mice showed that B cells are crucial for CCL19-mediated enhancement of tumor rejection, most likely as antigen-presenting B cells. DNA vaccines against Her2/neu may play a future role in the treatment of Her2/neu-positive breast cancer patients in a clinical situation of minimal residual disease.


Assuntos
Linfócitos B/imunologia , Biolística/métodos , Vacinas Anticâncer/administração & dosagem , Quimiocina CCL19/genética , Quimiocina CCL19/imunologia , Neoplasias Mamárias Experimentais/terapia , Receptor ErbB-2/imunologia , Vacinas de DNA/administração & dosagem , Animais , Vacinas Anticâncer/genética , Vacinas Anticâncer/imunologia , Linhagem Celular Tumoral , Quimiocina CCL19/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Injeções Intradérmicas , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Receptor ErbB-2/genética , Linfócitos T/imunologia , Vacinas de DNA/genética , Vacinas de DNA/imunologia
18.
Infection ; 40(4): 397-404, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22700379

RESUMO

PURPOSE: High-tech operations performed in cardiac surgery are associated with an increased risk of surgical site infections. In this study, we investigated if surgical site infections following cardiac surgery influence revision surgeries and patients' length of stay, and compared the results to German hospital infection surveillance data. METHODS: Over a period of 3 years, 2,621 patients of a cardiac surgery unit were enrolled following cardiac artery bypass graft surgery. Patients were examined for the incidence of surgical site infections, revision surgeries, and length of stay. The results were compared to the National Reference Center (NRC) data retrospectively. RESULTS: Of the observed population, 4.5 % suffer from surgical site infections, and in 7.7 % of the patients, revision surgery had to be performed. The length of stay was exceeded significantly for the patients with surgical site infections (average stay 14.5 vs. 42.2 days, p < 0.001). Compared to the NRC data, severe surgical site infections were not increased significantly. CONCLUSION: Surgical site infections resulted in revision surgeries with a significantly increased inpatient stay. However, this increase did not differ significantly from comparable German university hospitals.


Assuntos
Ponte de Artéria Coronária/efeitos adversos , Tempo de Internação , Infecção da Ferida Cirúrgica/epidemiologia , Adulto , Idoso , Ponte de Artéria Coronária/mortalidade , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Readmissão do Paciente , Reoperação , Infecção da Ferida Cirúrgica/microbiologia
19.
Z Gastroenterol ; 50(5): 453-6, 2012 May.
Artigo em Alemão | MEDLINE | ID: mdl-22581700

RESUMO

We report on the case of a segmentally emphasised, ulcerous chronic haemorrhagic colitis with the development of granulation tissue und scarred fibrosis with consecutive resulting stenosis of the colon. A 49-year-old male patient was infected with enterohaemorrhagic Escherichia coli bacteria during the EHEC-epidemic in northern Germany in early summer 2011. In the course of the infection the patient suffered from haemolytic uraemic syndrome (HUS) with acute renal failure and neurological symptoms. Haemodialysis and plasmapheresis had become mandatory. A simultaneous ileus was estimated to be of paralytic origin. One month after treatment of the acute phase of the infection a CT scan of the abdomen was performed and discovered a symptomatic stenosis of the proximal colon transversum. This obstruction needed to be treated by performing a right hemicolectomy with an ileo-transverso anastomosis. After surgery the patient recovered continuously. The histopathological examination verified an ulcerous-chronic haemorrhagic colitis on the background of an EHEC infection.


Assuntos
Colite/microbiologia , Doenças do Colo/microbiologia , Escherichia coli Êntero-Hemorrágica/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Hemorragia Gastrointestinal/microbiologia , Obstrução Intestinal/microbiologia , Úlcera/microbiologia , Humanos , Íleus/microbiologia , Masculino , Pessoa de Meia-Idade
20.
Mucosal Immunol ; 5(4): 377-87, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22395421

RESUMO

The chemokine receptor CCR7 is a central regulator in the maintenance of cellular homeostasis of mucosal tissues. CCR7⁻/⁻ mice develop autoimmune gastritis and exocrinopathy accompanied by the formation of mucosal tertiary lymphoid follicles. Here we found that CCR7-deficient mice frequently suffered from chronic diarrhea linked with increased gastrointestinal motility and the development of severe anorectal prolapse. Enhanced formation of intestinal lymphoid follicles was associated with an elevated proportion of activated colonic T cells and increased production of the cytokine interleukin (IL)-1ß. To uncover the pathomechanisms of diarrhea in CCR7⁻/⁻ mice, colonic epithelial barrier and ion channel activities were analyzed in Ussing chambers. Although overt acute colitis was absent, CCR7 deficiency resulted in reduced electrogenic sodium absorption and colonic chloride secretion. As it is known that IL-1ß regulates epithelial sodium channel (ENaC) activity, these data imply a causal link between CCR7 expression, IL-1ß level, and Na⁺ malabsorption owing to altered ENaC expression and diarrhea.


Assuntos
Colite/genética , Colite/metabolismo , Diarreia/genética , Diarreia/metabolismo , Transporte de Íons , Receptores CCR7/deficiência , Animais , Biomarcadores , Cloretos/metabolismo , Colo/imunologia , Colo/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Canais Epiteliais de Sódio/genética , Canais Epiteliais de Sódio/metabolismo , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Interleucina-1beta/biossíntese , Mucosa Intestinal , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , RNA Mensageiro/metabolismo , Receptores CCR7/genética , Prolapso Retal/genética , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo
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