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1.
J Cancer Res Clin Oncol ; 149(3): 1331-1341, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36513815

RESUMO

PURPOSE: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new, palliative approach for patients with peritoneal surface malignancies (PSMs). Its main goals are to control symptoms and ascites. For this experimental procedure, treatment efficacy and patient safety need to be closely monitored. METHODS: We performed a prospective registry study for patients with PSMs. Cisplatin (C) (7.5 mg/m2 body surface) and doxorubicin (D) (1.5 mg/m2) were administered laparoscopically via PIPAC. RESULTS: Between November 2015 and June 2020, we recorded data from 108 patients and 230 scheduled procedures. Tumor burden, patient fitness, quality of life, operating time and in-hospital stay remained stable over consecutive procedures. We recorded 21 non-access situations and 14 intraoperative complications (11 intestinal injuries, and three aspirations while inducing anesthesia). Three or more previous abdominal surgeries or cytoreductive surgery (CRS) with intraperitoneal hyperthermic chemoperfusion (HIPEC) were risk factors for non-access and intestinal injuries (χ2, p ≤ 0.01). Five Grade IV and three Grade V postoperative complications according to the Clavien-Dindo Classification (CDC) occurred. Median overall survival was 264 days (interquartile range 108-586). Therapies were primarily discontinued because of death (34%), progressive (26%), or regressive (16%) disease. CONCLUSION: PIPAC is effective in stabilizing PSMs and retaining quality of life in selected patients. Earlier abdominal surgeries and CRS with HIPEC should be considered when determining the indication for PIPAC. Randomized controlled studies are needed to evaluate PIPAC's therapeutic benefits compared to systemic chemotherapy (sCHT) alone. TRIAL REGISTRATION: NCT03100708 (April 2017).


Assuntos
Neoplasias Peritoneais , Humanos , Aerossóis/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Qualidade de Vida , Sistema de Registros
2.
Phys Rev Lett ; 131(26): 262501, 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38215380

RESUMO

The excited states of unstable ^{20}O were investigated via γ-ray spectroscopy following the ^{19}O(d,p)^{20}O reaction at 8 AMeV. By exploiting the Doppler shift attenuation method, the lifetimes of the 2_{2}^{+} and 3_{1}^{+} states were firmly established. From the γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+} and 3_{1}^{+} states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of γ-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.

3.
Sci Rep ; 11(1): 10022, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976338

RESUMO

Patients with locally advanced colon cancer have worse outcomes. Guidelines of various organizations are conflicting about the use of laparoscopic colectomy (LC) in locally advanced colon cancer. We determined whether patient outcomes of LC and open colectomy (OC) for locally advanced (T4) colon cancer are comparable in all colon cancer patients, T4a versus T4b patients, obese versus non-obese patients, and tumors located in the ascending, descending, and transverse colon. We used data from the 2013-2015 American College of Surgeons' National Surgical Quality Improvement Program. Patients were diagnosed with nonmetastatic pT4 colon cancer, with or without obstruction, and underwent LC (n = 563) or OC (n = 807). We used a composite outcome score (mortality, readmission, re-operation, wound infection, bleeding transfusion, and prolonged postoperative ileus); length of stay; and length of operation. Patients undergoing LC exhibited a composite outcome score that was 9.5% lower (95% CI - 15.4; - 3.5) versus those undergoing OC. LC patients experienced a 11.3% reduction in postoperative ileus (95% CI - 16.0; - 6.5) and an average of 2 days shorter length of stay (95% CI - 2.9; - 1.0). Patients undergoing LC were in the operating room an average of 13.5 min longer (95% CI 1.5; 25.6). We found no evidence for treatment heterogeneity across subgroups (p > 0.05). Patients with locally advanced colon cancer who receive LC had better overall outcomes and shorter lengths of stay compared with OC patients. LC was equally effective in obese/nonobese patients, in T4a/T4b patients, and regardless of the location of the tumor.


Assuntos
Colectomia/estatística & dados numéricos , Neoplasias do Colo/cirurgia , Laparoscopia/estatística & dados numéricos , Adulto , Idoso , Estudos de Coortes , Colo/patologia , Colo/cirurgia , Neoplasias do Colo/complicações , Neoplasias do Colo/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Resultado do Tratamento
4.
Exp Mech ; 61(1): 203-216, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33776072

RESUMO

BACKGROUND: Mouse models of abdominal aortic aneurysm (AAA) and dissection have proven to be invaluable in the advancement of diagnostics and therapeutics by providing a platform to decipher response variables that are elusive in human populations. One such model involves systemic Angiotensin II (Ang-II) infusion into low density-lipoprotein receptor-deficient (LDLr-/-) mice leading to intramural thrombus formation, inflammation, matrix degradation, dilation, and dissection. Despite its effectiveness, considerable experimental variability has been observed in AAAs taken from our Ang-II infused LDLr-/- mice (n=12) with obvious dissection occurring in 3 samples, outer bulge radii ranging from 0.73 to 2.12 mm, burst pressures ranging from 155 to 540 mmHg, and rupture location occurring 0.05 to 2.53 mm from the peak bulge location. OBJECTIVE: We hypothesized that surface curvature, a fundamental measure of shape, could serve as a useful predictor of AAA failure at supra-physiological inflation pressures. METHODS: To test this hypothesis, we fit well-known biquadratic surface patches to 360° micro-mechanical test data and used Spearman's rank correlation (rho) to identify relationships between failure metrics and curvature indices. RESULTS: We found the strongest associations between burst pressure and the maximum value of the first principal curvature (rho=-0.591, p-val=0.061), the maximum value of Mean curvature (rho=-0.545, p-val=0.087), and local values of Mean curvature at the burst location (rho=-0.864, p-val=0.001) with only the latter significant after Bonferroni correction. Additionally, the surface profile at failure was predominantly convex and hyperbolic (saddle-shaped) as indicated by a negative sign in the Gaussian curvature. Findings reiterate the importance of shape in experimental models of AAA.

5.
Phys Rev Lett ; 126(3): 032503, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33543956

RESUMO

A nuclear spectroscopy experiment was conducted to study α-decay chains stemming from isotopes of flerovium (element Z=114). An upgraded TASISpec decay station was placed behind the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. The fusion-evaporation reactions ^{48}Ca+^{242}Pu and ^{48}Ca+^{244}Pu provided a total of 32 flerovium-candidate decay chains, of which two and eleven were firmly assigned to ^{286}Fl and ^{288}Fl, respectively. A prompt coincidence between a 9.60(1)-MeV α particle event and a 0.36(1)-MeV conversion electron marked the first observation of an excited state in an even-even isotope of the heaviest man-made elements, namely ^{282}Cn. Spectroscopy of ^{288}Fl decay chains fixed Q_{α}=10.06(1) MeV. In one case, a Q_{α}=9.46(1)-MeV decay from ^{284}Cn into ^{280}Ds was observed, with ^{280}Ds fissioning after only 518 µs. The impact of these findings, aggregated with existing data on decay chains of ^{286,288}Fl, on the size of an anticipated shell gap at proton number Z=114 is discussed in light of predictions from two beyond-mean-field calculations, which take into account triaxial deformation.

6.
Anim Genet ; 51(3): 420-422, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32065671

RESUMO

Homozygous and compound heterozygous Miniature horses for ACAN alleles D1, D2, D3* and D4 exhibit chondrodysplastic dwarfism (OMIA 001271-9796). In a previous study, the carrier rate for these four alleles, combined, was 26.2%. The purpose of this study was to investigate whether carriers of these dwarfism-causing alleles had a shorter withers height than non-carriers. A total of 245 Miniature horses were tested for these four ACAN alleles and also were measured for withers height. Of these horses, 98 were carriers and 147 were non-carriers. A statistically significant difference of 1.43 inches was observed with the carriers being shorter (P = 1.72E - 11). The range of heights for the two groups overlapped, indicating that other factors, including genes, have an impact on withers height. However, the high carrier rate of these dwarfism-causing variants may be due to selection for decreased height.


Assuntos
Agrecanas/genética , Nanismo/veterinária , Doenças dos Cavalos/genética , Agrecanas/metabolismo , Alelos , Animais , Nanismo/genética , Heterozigoto , Cavalos
7.
Phys Rev Lett ; 124(6): 062501, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32109090

RESUMO

The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N=Z) nuclide _{44}^{88}Ru_{44} has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in ^{88}Ru were populated via the ^{54}Fe(^{36}Ar,2nγ)^{88}Ru^{*} fusion-evaporation reaction at the Grand Accélérateur National d'Ions Lourds (GANIL) accelerator complex. The observed γ-ray cascade is assigned to ^{88}Ru using clean prompt γ-γ-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N>Z nuclides. The direct observation of such a "delayed" rotational alignment in a deformed N=Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.

8.
Anim Genet ; 49(5): 413-420, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30058072

RESUMO

Chondrodysplastic dwarfism in Miniature horses appeared to be a recessive genetic trait based on the occurrence of affected offspring by normal parents. Dwarf phenotypes vary and range from abnormal abortuses to viable offspring with evidence of skeletal dysplasia. A genome-wide association study implicated a region of ECA1 with dwarfism in Miniature horses. Aggrecan (ACAN) was a candidate gene in that region, and exons were sequenced to compare DNA sequences for dwarf and non-dwarf horses. Sequencing led to the discovery of variants in exons 2, 6, 7 and 15 associated with dwarfism. The four variants are identified with reference to Ecab 3.0 (GCF_002863925.1) as g.95291270del (rs1095048841), g.95284530C>T (ERP107353), g.95282140C>G (rs1095048823) and g.95257480_95257500del (rs1095048839) and designated here as D1, D2, D3* and D4 respectively. A previous study at another laboratory reported dwarfism associated with homozygosity for D3*. Homozygotes for those variants and compound heterozygotes for any combination of those variants always expressed a dwarfism phenotype. However, eight additional horses with dwarfism were found, seven of which were heterozygotes for D2, D3* or D4, suggesting the existence of additional ACAN alleles causing dwarfism. Among Miniature horses, the combined frequency of D1, D2, D3* and D4 was 0.163, suggesting a carrier rate of 26.2% for alleles causing chondrodysplastic dwarfism.


Assuntos
Agrecanas/genética , Nanismo/veterinária , Doenças dos Cavalos/genética , Polimorfismo de Nucleotídeo Único , Animais , Nanismo/genética , Éxons , Cavalos
9.
J Appl Stat ; 45(3): 568-585, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30906096

RESUMO

In this paper we propose a novel Bayesian statistical methodology for spatial survival data. Our methodology broadens the definition of the survival, density and hazard functions by explicitly modeling the spatial dependency using direct derivations of these functions and their marginals and conditionals. We also derive spatially dependent likelihood functions. Finally we examine the applications of these derivations with geographically augmented survival distributions in the context of the Louisiana Surveillance, Epidemiology, and End Results (SEER) registry prostate cancer data.

10.
J Gastrointest Surg ; 21(8): 1296-1303, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28567574

RESUMO

BACKGROUND: We compared patient outcomes of robot-assisted surgery (RAS) and laparoscopic colectomy without robotic assistance for colon cancer or nonmalignant polyps, comparing all patients, obese versus nonobese patients, and male versus female patients. METHODS: We used the 2013-2015 American College of Surgeons National Surgical Quality Improvement Program data to examine a composite outcome score comprised of mortality, readmission, reoperation, wound infection, bleeding transfusion, and prolonged postoperative ileus. We used propensity scores to assess potential heterogeneous treatment effects of RAS by patient obesity and sex. RESULTS: In all, 17.1% of the 10,844 of patients received RAS. Males were slightly more likely to receive RAS. Obese patients were equally likely to receive RAS as nonobese patients. In comparison to nonRAS, RAS was associated with a 3.1% higher adverse composite outcome score. Mortality, reoperations, wound infections, sepsis, pulmonary embolisms, deep vein thrombosis, myocardial infarction, blood transfusions, and average length of hospitalization were similar in both groups. Conversion to open surgery was 10.1% lower in RAS versus nonRAS patients, but RAS patients were in the operating room an average of 52.4 min longer. We found no statistically significant differences (p > 0.05) by obesity status and gender. CONCLUSIONS: Worse patient outcomes and no differential improvement by sex or obesity suggest more cautious adoption of RAS.


Assuntos
Colectomia/métodos , Neoplasias do Colo/cirurgia , Pólipos do Colo/cirurgia , Laparoscopia/estatística & dados numéricos , Padrões de Prática Médica/estatística & dados numéricos , Procedimentos Cirúrgicos Robóticos/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/complicações , Neoplasias do Colo/mortalidade , Pólipos do Colo/complicações , Pólipos do Colo/mortalidade , Pesquisa Comparativa da Efetividade , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Pontuação de Propensão , Resultado do Tratamento , Estados Unidos
11.
Phys Rev Lett ; 117(22): 222302, 2016 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-27925748

RESUMO

The ^{54}Fe nucleus was populated from a ^{56}Fe beam impinging on a Be target with an energy of E/A=500 MeV. The internal decay via γ-ray emission of the 10^{+} metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the ^{56}Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of ^{54}Fe, suggesting that it was populated via the decay of the Δ^{0} resonance into a proton. This process allows the population of four-nucleon states, such as the observed isomer. Therefore, it is concluded that the observation of this 10^{+} metastable state in ^{54}Fe is a consequence of the quark structure of the nucleons.

12.
Phys Rev Lett ; 117(6): 062501, 2016 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-27541463

RESUMO

Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

13.
Anim Genet ; 47(5): 603-5, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27295976

RESUMO

Horse owners choose whether or not to train American Saddlebred horses (ASHs) to perform the 4-beat gaits called rack and slow gait. The rack and slow gait are similar to ambling gaits shown to be associated with variation in the DMRT3 gene in other breeds but are trained rather than naturally occurring gaits. A premature stop codon in the DMRT3 gene (DMRT3_Ser301STOP) caused by the Ch23:g.22999655C>A SNP has an effect on the pattern of locomotion in horses and allows for the pacing gait and strong association with performance of ambling gaits in diverse breeds. We used horse show records to identify ASHs trained to perform as 5-gaited horses and compared them to other Saddlebreds for the prevalence of the A allele of the Ch23:g.22999655C>A SNP of DMRT3. Genomic DNA was typed using a PCR-RFLP technique for 5-gaited ASHs (n = 55), 3-gaited or harness ASHs (n = 64) and ASHs not shown (n = 128). We did not observe differences in the frequencies of the Ch23:g.22999655C>A SNP of DMRT3 when comparing 5-gaited ASHs to other ASHs (P > 0.22). These results suggest that DMRT3 alleles do not affect the choice of breeders to train and show ASHs as 5-gaited horses.


Assuntos
Cruzamento , Marcha/genética , Cavalos/genética , Fatores de Transcrição/genética , Alelos , Animais , Códon sem Sentido , Frequência do Gene , Genótipo , Polimorfismo de Nucleotídeo Único , Estados Unidos
14.
Phys Rev Lett ; 115(22): 222502, 2015 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-26650299

RESUMO

The isospin mixing was deduced in the compound nucleus ^{80}Zr at an excitation energy of E^{*}=54 MeV from the γ decay of the giant dipole resonance. The reaction ^{40}Ca+^{40}Ca at E_{beam}=136 MeV was used to form the compound nucleus in the isospin I=0 channel, while the reaction ^{37}Cl+^{44}Ca at E_{beam}=95 MeV was used as the reference reaction. The γ rays were detected with the AGATA demonstrator array coupled with LaBr_{3}:Ce detectors. The temperature dependence of the isospin mixing was obtained and the zero-temperature value deduced. The isospin-symmetry-breaking correction δ_{C} used for the Fermi superallowed transitions was extracted and found to be consistent with ß-decay data.

15.
BMJ Open ; 5(6): e006678, 2015 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-26056120

RESUMO

OBJECTIVES: We examined the utility of January 2004 to April 2014 Google Trends data from information searches for cancer screenings and preparations as a complement to population screening data, which are traditionally estimated through costly population-level surveys. SETTING: State-level data across the USA. PARTICIPANTS: Persons who searched for terms related to cancer screening using Google, and persons who participated in the Behavioral Risk Factor Surveillance System (BRFSS). PRIMARY AND SECONDARY OUTCOME MEASURES: (1) State-level Google Trends data, providing relative search volume (RSV) data scaled to the highest search proportion per week (RSV100) for search terms over time since 2004 and across different geographical locations. (2) RSV of new screening tests, free/low-cost screening for breast and colorectal cancer, and new preparations for colonoscopy (Prepopik). (3) State-level breast, cervical, colorectal and prostate cancer screening rates. RESULTS: Correlations between Google Trends and BRFSS data ranged from 0.55 for ever having had a colonoscopy to 0.14 for having a Pap smear within the past 3 years. Free/low-cost mammography and colonoscopy showed higher RSV during their respective cancer awareness months. RSV for Miralax remained stable, while interest in Prepopik increased over time. RSV for lung cancer screening, virtual colonoscopy and three-dimensional mammography was low. CONCLUSIONS: Google Trends data provides enormous scientific possibilities, but are not a suitable substitute for, but may complement, traditional data collection and analysis about cancer screening and related interests.


Assuntos
Coleta de Dados/métodos , Detecção Precoce de Câncer , Comportamento de Busca de Informação , Programas de Rastreamento , Neoplasias/diagnóstico , Aceitação pelo Paciente de Cuidados de Saúde , Ferramenta de Busca/tendências , Adolescente , Adulto , Conscientização , Colonoscopia , Custos e Análise de Custo , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Internet , Masculino , Mamografia , Inquéritos e Questionários , Esfregaço Vaginal
16.
Phys Rev Lett ; 113(1): 012501, 2014 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-25032921

RESUMO

The properties of pygmy dipole states in 208Pb were investigated using the 208Pb(17O, 17O'γ) reaction at 340 MeV and measuring the γ decay with high resolution with the AGATA demonstrator array. Cross sections and angular distributions of the emitted γ rays and of the scattered particles were measured. The results are compared with (γ, γ') and (p, p') data. The data analysis with the distorted wave Born approximation approach gives a good description of the elastic scattering and of the inelastic excitation of the 2+ and 3- states. For the dipole transitions a form factor obtained by folding a microscopically calculated transition density was used for the first time. This has allowed us to extract the isoscalar component of the 1- excited states from 4 to 8 MeV.

17.
Ann Biomed Eng ; 42(6): 1207-23, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24590490

RESUMO

The continuing lack of longitudinal histopathological and biomechanical data for human arteries in health and disease highlights the importance of studying the many genetic, pharmacological, and surgical models that are available in mice. As a result, there has been a significant increase in the number of reports on the biomechanics of murine arteries over the past decade, particularly for the common carotid artery. Whereas most of these studies have focused on wild-type controls or comparing controls vs. a single model of altered hemodynamics or vascular disease, there is a pressing need to compare results across many different models to understand more broadly the effects of genetic mutations, pharmacological treatments, or surgical alterations on the evolving hemodynamics and the microstructure and biomechanical properties of these vessels. This paper represents a first step toward this goal, that is, a biomechanical phenotyping of common carotid arteries from control mice and seven different mouse models that represent alterations in elastic fiber integrity, collagen remodeling, and smooth muscle cell functionality.


Assuntos
Doenças das Artérias Carótidas/genética , Doenças das Artérias Carótidas/fisiopatologia , Artéria Carótida Primitiva/fisiopatologia , Hemodinâmica , Modelos Cardiovasculares , Animais , Fenômenos Biomecânicos/genética , Doenças das Artérias Carótidas/tratamento farmacológico , Doenças das Artérias Carótidas/patologia , Artéria Carótida Primitiva/patologia , Modelos Animais de Doenças , Humanos , Camundongos
18.
J Biomech ; 45(4): 660-5, 2012 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-22236532

RESUMO

Intraluminal exposure of the infrarenal aorta to porcine pancreatic elastase represents one of the most commonly used experimental models of the development and progression of abdominal aortic aneurysms. Morphological and histological effects of elastase on the aortic wall have been well documented in multiple rodent models, but there has been little attention to the associated effects on mechanical properties. In this paper, we present the first biaxial mechanical data on, and associated nonlinear constitutive descriptors of, the effects of elastase on the infrarenal aorta in mice. Quantification of the dramatic, acute effects of elastase on wall behavior in vitro is an essential first step toward understanding the growth and remodeling of aneurysms in vivo, which depends on both the initial changes in the mechanics and the subsequent inflammation-mediated turnover of cells and extracellular matrix that contributes to the evolving mechanics.


Assuntos
Aorta Abdominal/fisiopatologia , Aneurisma da Aorta Abdominal/fisiopatologia , Modelos Cardiovasculares , Elastase Pancreática/efeitos adversos , Animais , Aorta Abdominal/metabolismo , Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/induzido quimicamente , Aneurisma da Aorta Abdominal/metabolismo , Aneurisma da Aorta Abdominal/patologia , Modelos Animais de Doenças , Matriz Extracelular/metabolismo , Masculino , Camundongos , Elastase Pancreática/farmacologia , Suínos
19.
J Biomech ; 44(14): 2532-7, 2011 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-21851943

RESUMO

Quantifying the time course of load-induced changes in arterial wall geometry, microstructure, and properties is fundamental to developing mathematical models of growth and remodeling. Arteries adapt to altered pressure and flow by modifying wall thickness, inner diameter, and axial length via marked cell and matrix turnover. To estimate particular biomaterial implications of such adaptations, we used a 4-fiber family constitutive relation to quantify passive biaxial mechanical behaviors of mouse carotid arteries 0 (control), 7-10, 10-14, or 35-56 days after an aortic arch banding surgery that increased pulse pressure and pulsatile flow in the right carotid artery. In vivo circumferential and axial stretches at mean arterial pressure were, for example, 11% and 26% lower, respectively, in hypertensive carotids 35-56 days after banding than in normotensive controls; this finding is consistent with observations that hypertension decreases distensibility. Interestingly, the strain energy W stored in the carotids at individual in vivo conditions was also less in hypertensive compared with normotensive carotids. For example, at 35-56 days after banding, W was 24%, 39%, and 47% of normal values at diastolic, mean, and systolic pressures, respectively. The energy stored during the cardiac cycle, W(sys)-W(dias), also tended to be less, but this reduction did not reach significance. When computed at normal in vivo values of biaxial stretch, however, W was well above normal for the hypertensive carotids. This net increase resulted from an overall increase in the collagen-related anisotropic contribution to W despite a decrease in the elastin-related isotropic contribution. The latter was consistent with observed decreases in the mass fraction of elastin.


Assuntos
Artéria Carótida Primitiva/fisiopatologia , Hipertensão/fisiopatologia , Animais , Fenômenos Biomecânicos , Doenças das Artérias Carótidas/fisiopatologia , Colágeno/metabolismo , Modelos Animais de Doenças , Elastina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fluxo Pulsátil , Estresse Mecânico
20.
Math Med Biol ; 27(4): 343-71, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20484365

RESUMO

Motivated by recent clinical and laboratory findings of important effects of pulsatile pressure and flow on arterial adaptations, we employ and extend an established constrained mixture framework of growth (change in mass) and remodelling (change in structure) to include such dynamical effects. New descriptors of cell and tissue behavior (constitutive relations) are postulated and refined based on new experimental data from a transverse aortic arch banding model in the mouse that increases pulsatile pressure and flow in one carotid artery. In particular, it is shown that there was a need to refine constitutive relations for the active stress generated by smooth muscle, to include both stress- and stress rate-mediated control of the turnover of cells and matrix and to account for a cyclic stress-mediated loss of elastic fibre integrity and decrease in collagen stiffness in order to capture the reported evolution, over 8 weeks, of luminal radius, wall thickness, axial force and in vivo axial stretch of the hypertensive mouse carotid artery. We submit, therefore, that complex aspects of adaptation by elastic arteries can be predicted by constrained mixture models wherein individual constituents are produced or removed at individual rates and to individual extents depending on changes in both stress and stress rate from normal values.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea/fisiologia , Artéria Carótida Primitiva/fisiologia , Artéria Carótida Primitiva/fisiopatologia , Modelos Cardiovasculares , Contração Miocárdica/fisiologia , Algoritmos , Animais , Fenômenos Biomecânicos , Artéria Carótida Primitiva/patologia , Colágeno/metabolismo , Simulação por Computador , Elasticidade , Elastina/metabolismo , Matriz Extracelular/fisiologia , Hipertensão/patologia , Hipertensão/fisiopatologia , Camundongos , Músculo Liso Vascular/fisiologia , Músculo Liso Vascular/fisiopatologia , Fluxo Pulsátil/fisiologia , Estresse Mecânico
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