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INTRODUCTION: Immune checkpoint inhibition (ICI) has improved patients' outcomes in advanced melanoma, often resulting in durable response. However, not all patients have durable responses and the patients with dissociated response are a valuable subgroup to identify mechanisms of ICI resistance. METHODS: Stage IV melanoma patients treated with ICI and dissociated response were retrospectively screened for available samples containing sufficient tumor at least at two time-points. Included were one patient with metachronous regressive and progressive lesions at the same site, two patients with regressive and novel lesion at different sites, and three patients with regressive and progressive lesions at different sites. In addition, four patients with acquired resistant tumor samples without a matched second sample were included. RESULTS: In the majority of patients, the progressive tumor lesion contained higher CD8+ T cell counts/mm2 and interferon-gamma (IFNγ) signature level, but similar tumor PD-L1 expression. The tumor mutational burden levels were in 2 out 3 lesions higher compared to the corresponding regressive tumors lesion. In the acquired tumor lesions, high CD8+/mm2 and relatively high IFNγ signature levels were observed. In one patient in both the B2M and PTEN gene a stop gaining mutation and in another patient a pathogenic POLE mutation were found. CONCLUSION: Intrapatient comparison of progressive versus regressive lesions indicates no defect in tumor T cell infiltration, and in general no tumor immune exclusion were observed.
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Melanoma , Humanos , Inhibidores de Puntos de Control Inmunológico , Estudios Retrospectivos , Linfocitos T CD8-positivos , Interferón gammaRESUMEN
BACKGROUND: Neoadjuvant ipilimumab plus nivolumab has yielded high response rates in patients with macroscopic stage III melanoma. These response rates translated to high short-term survival rates. However, data on long-term survival and disease recurrence are lacking. PATIENTS AND METHODS: In OpACIN, 20 patients with macroscopic stage III melanoma were randomized to ipilimumab 3 mg/kg plus nivolumab 1 mg/kg q3w four cycles of adjuvant or split two cycles of neoadjuvant and two adjuvant. In OpACIN-neo, 86 patients with macroscopic stage III melanoma were randomized to arm A (2× ipilimumab 3 mg/kg plus nivolumab 1 mg/kg q3w; n = 30), arm B (2× ipilimumab 1 mg/kg plus nivolumab 3 mg/kg q3w; n = 30), or arm C (2× ipilimumab 3 mg/kg q3w plus 2× nivolumab 3 mg/kg q2w; n = 26) followed by surgery. RESULTS: The median recurrence-free survival (RFS) and overall survival (OS) were not reached in either trial. After a median follow-up of 69 months for OpACIN, 1/7 patients with a pathologic response to neoadjuvant therapy had disease recurrence. The estimated 5-year RFS and OS rates for the neoadjuvant arm were 70% and 90% versus 60% and 70% for the adjuvant arm. After a median follow-up of 47 months for OpACIN-neo, the estimated 3-year RFS and OS rates were 82% and 92%, respectively. The estimated 3-year RFS rate for OpACIN-neo was 95% for patients with a pathologic response versus 37% for patients without a pathologic response (P < 0.001). In multiple regression analyses, pathologic response was the strongest predictor of disease recurrence. Of the 12 patients with distant disease recurrence after neoadjuvant therapy, 5 responded to subsequent anti-PD-1 and 8 to targeted therapy, although 7 patients showed progression after the initial response. CONCLUSIONS: Updated data confirm the high survival rates after neoadjuvant combination checkpoint inhibition in macroscopic stage III melanoma, especially for patients with a pathologic response. Pathologic response is the strongest surrogate marker for long-term outcome.
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Melanoma , Nivolumab , Humanos , Nivolumab/uso terapéutico , Ipilimumab/efectos adversos , Terapia Neoadyuvante , Melanoma/patología , Adyuvantes Inmunológicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Melanoma Cutáneo MalignoRESUMEN
BACKGROUND: Immune checkpoint inhibitors (ICI) substantially improve outcome for patients with cancer. However, the majority of patients develops immune-related adverse events (irAEs), which can be persistent and significantly reduce quality of life. Neurological irAEs occur in 1-5% of patients and can induce severe, permanent sequelae or even be fatal. In order to improve the diagnosis and treatment of neurological irAEs and to better understand their pathogenesis, we assessed whether previous neurotropic infections are associated with neurological irAEs. METHODS: Neurotropic infections that might predispose to ICI-induced neurological irAEs were analyzed in 61 melanoma patients from 3 countries, the Netherlands, Australia and Germany, including 24 patients with neurotoxicity and 37 control patients. In total, 14 viral, 6 bacterial, and 1 protozoal infections previously reported to trigger neurological pathologies were assessed using routine serology testing. The Dutch and Australian cohorts (NL) included pre-treatment plasma samples of patients treated with neoadjuvant ICI therapy (OpACIN-neo and PRADO trials; NCT02977052). In the Dutch/Australian cohort a total of 11 patients with neurological irAEs were compared to 27 control patients (patients without neurological irAEs). The German cohort (LMU) consisted of serum samples of 13 patients with neurological irAE and 10 control patients without any documented irAE under ICI therapy. RESULTS: The association of neurological irAEs with 21 possible preceding infections was assessed by measuring specific antibodies against investigated agents. The seroprevalence of all the tested viral (cytomegalovirus, Epstein-Barr-Virus, varicella-zoster virus, measles, rubella, influenza A and B, human herpes virus 6 and 7, herpes simplex virus 1 and 2, parvovirus B19, hepatitis A and E and human T-lymphotropic virus type 1 and 2), bacterial (Borrelia burgdorferi sensu lato, Campylobacter jejuni, Mycoplasma pneumoniae, Coxiella burnetti, Helicobacter pylori, Yersinia enterocolitica and Y. pseudotuberculosis) and protozoal (Toxoplasma gondii) infections was similar for patients who developed neurological irAEs as compared to control patients. Thus, the analysis provided no evidence for an association of described agents tested for seroprevalence with ICI induced neurotoxicity. CONCLUSION: Previous viral, bacterial and protozoal neurotropic infections appear not to be associated with the development of neurological irAEs in melanoma patients who underwent therapy with ICI across 3 countries. Further efforts are needed to unravel the factors underlying neurological irAEs in order to identify risk factors for these toxicities, especially with the increasing use of ICI in earlier stage disease.
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Antineoplásicos Inmunológicos , Melanoma , Humanos , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Estudios Seroepidemiológicos , Calidad de Vida , Antineoplásicos Inmunológicos/uso terapéutico , Australia/epidemiología , Melanoma/tratamiento farmacológico , Estudios RetrospectivosRESUMEN
We study the bending mode of pure water and charged aqueous surfaces using heterodyne-detected vibrational sum-frequency generation spectroscopy. We observe a low (1626 cm^{-1}) and a high (1656 cm^{-1}) frequency component that can be unambiguously assigned to an interfacial dipole and a bulk quadrupolar response, respectively. We thus demonstrate that probing the bending mode provides structural and quantitative information on both the surface and the bulk.
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BACKGROUND: Disease recurrence remains the major cause of death in adults with acute myeloid leukaemia (AML) treated using either intensive chemotherapy (IC) or allogenic stem cell transplantation (allo-SCT). AIMS: The timely delivery of maintenance drug or cellular therapies represent emerging strategies with the potential to reduce relapse after both treatment modalities, but whilst the determinants of overall relapse risk have been extensively characterized the factors determining the timing of disease recurrence have not been characterized. MATERIALS AND METHODS: We have therefore examined, using a series of sequential landmark analyses, relapse kinetics in a cohort of 2028 patients who received an allo-SCT for AML in CR1 and separately 570 patients treated with IC alone. RESULTS: In the first 3 months after allo-SCT, the factors associated with an increased risk of relapse included the presence of the FLT3-ITD (P < 0.001), patient age (P = 0.012), time interval from CR1 to transplant (P < 0.001) and donor type (P = 0.03). Relapse from 3 to 6 months was associated with a higher white cell count at diagnosis (P = 0.001), adverse-risk cytogenetics (P < 0.001), presence of FLT3-ITD mutation (P < 0.001) and time interval to achieve first complete remission (P = 0.013). Later relapse was associated with adverse cytogenetics, mutated NPM1, absence of chronic graft-versus-host disease (GVHD) and the use of in vivo T-cell depletion. In patients treated with IC alone, the factors associated with relapse in the first 3 months were adverse-risk cytogenetics (P < 0.001) and FLT3-ITD status (P = 0.001). The factors predicting later relapse were the time interval from diagnosis to CR1 (P = 0.22) and time interval from CR1 to IC (P = 0.012). DISCUSSION AND CONCLUSION: Taken together, these data provide novel insights into the biology of disease recurrence after both allo-SCT and IC and have the potential to inform the design of novel maintenance strategies in both clinical settings.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Leucemia Mieloide Aguda/terapia , Trasplante de Células Madre de Sangre Periférica , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nucleofosmina , Recurrencia , Estudios Retrospectivos , Trasplante Homólogo , Adulto JovenRESUMEN
Temperature-dependent sum-frequency scattering spectroscopy is used to study the properties of hexadecane and dodecane oil droplets in water. The sum-frequency scattering spectra contain vibrational bands that correspond to the symmetric and antisymmetric CH stretching vibrations of the methylene (CH2) and methyl (CH3) groups of the alkane molecules. The relative amplitudes of the vibrational bands provide information on the surface structure and the shape of the oil droplets. We study the sum-frequency scattering spectra over a temperature range of -48 to 24 °C, including the freezing transitions of the water matrix and the oil droplets. Hexadecane oil droplets freeze at a higher temperature than the surrounding water, whereas dodecane oil droplets freeze at a lower temperature than the surrounding water. This allows us to independently study the freezing effect of oil and water on the surface structure of the oil droplets. In both cases, freezing leads to a change in the polarization dependencies that are valid in the case of the spherical-symmetric shapes that the oil droplets assume when both water and oil are liquid. We find that the freezing of water leads to a strong distortion of the liquid dodecane surface but has little effect on the surface of already solidified hexadecane. For completely frozen emulsions a further decrease in temperature is observed to lead to a further distortion of the surface of the solid oil particles, which might be caused by increasing hardness of the ice matrix encapsulating the particles.
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Neoadjuvant ipilimumab plus nivolumab showed high pathologic response rates (pRRs) in patients with macroscopic stage III melanoma in the phase 1b OpACIN ( NCT02437279 ) and phase 2 OpACIN-neo ( NCT02977052 ) studies1,2. While the results are promising, data on the durability of these pathologic responses and baseline biomarkers for response and survival were lacking. After a median follow-up of 4 years, none of the patients with a pathologic response (n = 7/9 patients) in the OpACIN study had relapsed. In OpACIN-neo (n = 86), the 2-year estimated relapse-free survival was 84% for all patients, 97% for patients achieving a pathologic response and 36% for nonresponders (P < 0.001). High tumor mutational burden (TMB) and high interferon-gamma-related gene expression signature score (IFN-γ score) were associated with pathologic response and low risk of relapse; pRR was 100% in patients with high IFN-γ score/high TMB; patients with high IFN-γ score/low TMB or low IFN-γ score/high TMB had pRRs of 91% and 88%; while patients with low IFN-γ score/low TMB had a pRR of only 39%. These data demonstrate long-term benefit in patients with a pathologic response and show the predictive potential of TMB and IFN-γ score. Our findings provide a strong rationale for a randomized phase 3 study comparing neoadjuvant ipilimumab plus nivolumab versus standard adjuvant therapy with antibodies against the programmed cell death protein-1 (anti-PD-1) in macroscopic stage III melanoma.
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Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Ipilimumab/administración & dosificación , Melanoma/tratamiento farmacológico , Nivolumab/administración & dosificación , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/genética , Antígeno B7-H1/inmunología , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/inmunología , Antígeno CTLA-4/antagonistas & inhibidores , Antígeno CTLA-4/genética , Antígeno CTLA-4/inmunología , Supervivencia sin Enfermedad , Femenino , Humanos , Inmunoterapia/efectos adversos , Interferón gamma/genética , Ipilimumab/efectos adversos , Masculino , Melanoma/inmunología , Melanoma/patología , Persona de Mediana Edad , Mutación/genética , Terapia Neoadyuvante/efectos adversos , Estadificación de Neoplasias , Nivolumab/efectos adversos , RecurrenciaRESUMEN
Invasive meningococcal disease is associated with significant mortality. Classic presentation consists of high fever, headache and neck stiffness. Neisseria meningitidis serogroup W may present with atypical symptoms, which complicates recognition. Furthermore, it is associated with a high case fatality rate.
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Diarrea/microbiología , Infecciones Meningocócicas/complicaciones , Infecciones Meningocócicas/microbiología , Neisseria meningitidis Serogrupo W-135 , Sepsis/microbiología , Diagnóstico Diferencial , Diarrea/diagnóstico , Femenino , Humanos , Infecciones Meningocócicas/diagnóstico , Sepsis/diagnóstico , Adulto JovenRESUMEN
Infectious mononucleosis may mimic lymphoma, both clinically and histopathologically. We present a patient with neurological symptoms and lymphadenopathy, initially diagnosed as Epstein-Barr virus (EBV)-positive angioimmunoblastic T-cell lymphoma (AITL) with cerebrospinal fluid (CSF) localisation based on lymph node pathology and a 30-fold higher EBV load in the CSF compared with serum. However, the patient fully recovered spontaneously and EBV became negative in both CSF and serum, suggestive of a dramatic presentation of EBV meningoencephalitis.
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Infecciones por Virus de Epstein-Barr/diagnóstico , Meningoencefalitis/diagnóstico , Meningoencefalitis/virología , Líquido Cefalorraquídeo/virología , Diagnóstico Diferencial , Humanos , Linfoma/diagnóstico , Masculino , Persona de Mediana EdadRESUMEN
A 73-year-old man, without any medical history, had presented with dark urine and pale stool without pain. Diagnostic imaging revealed a tumour in the pancreas with liver metastases. Histopathological examination showed a well-differentiated pancreatic neuroendocrine tumour. After a stable 2.5 years on everolimus, progression of the liver metastases was seen and a switch was made to chemotherapy. Three months later, he developed progressive spinal neurological symptoms. MRI of the spine and brain revealed leptomeningeal contrast-enhancing lesions. Cytopathological examination of the cerebrospinal fluid showed malignant epithelial cells compatible with well-differentiated neuroendocrine tumour. Epithelial cell-adhesion molecule-based flow cytometry of the cerebrospinal fluid confirmed the presence of epithelial tumour cells. Based on these results, the diagnosis of leptomeningeal metastases of an originally well-differentiated neuroendocrine tumour of the pancreas was made.
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Neoplasias Intestinales/patología , Neoplasias Hepáticas/patología , Neoplasias Meníngeas/patología , Tumores Neuroendocrinos/patología , Neoplasias Pancreáticas/patología , Neoplasias Gástricas/patología , Anciano , Líquido Cefalorraquídeo/citología , Quimioterapia/métodos , Everolimus/administración & dosificación , Everolimus/uso terapéutico , Resultado Fatal , Humanos , Inmunosupresores/uso terapéutico , Neoplasias Intestinales/diagnóstico por imagen , Neoplasias Intestinales/tratamiento farmacológico , Neoplasias Intestinales/secundario , Neoplasias Hepáticas/secundario , Imagen por Resonancia Magnética , Masculino , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/secundario , Metástasis de la Neoplasia , Tumores Neuroendocrinos/diagnóstico por imagen , Tumores Neuroendocrinos/tratamiento farmacológico , Tumores Neuroendocrinos/secundario , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/secundario , Neoplasias Gástricas/diagnóstico por imagen , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/secundarioRESUMEN
[This corrects the article DOI: 10.1021/acs.jpcc.7b03752.].
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We use heterodyne-detected vibrational sum-frequency generation (HD-VSFG) to determine the orientation of the molecular plane of methylguanidinium ions at the surface of aqueous solutions. We measure the VSFG response of the symmetric and antisymmetric methyl stretch vibrations of the methylguanidinium ion with different polarization combinations. We find that for at least 50% of the methylguanidinium ions the molecular plane is at an angle >20° with respect to the surface plane. Hence, for only a minor fraction of the ions does the molecular plane have an orientation (near-)parallel to the surface plane, in contrast to the predictions of recent molecular dynamics simulation studies.
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Post-remission treatment (PRT) in patients with cytogenetically normal (CN) acute myeloid leukemia (AML) in first complete remission (CR1) is debated. We studied 521 patients with CN-AML in CR1, for whom mutational status of NPM1 and FLT3-ITD was available, including the FLT3-ITD allelic ratio. PRT consisted of reduced intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (alloHSCT) (n=68), myeloablative conditioning (MAC) alloHSCT (n=137), autologous hematopoietic stem cell transplantation (autoHSCT) (n=168) or chemotherapy (n=148). Favorable overall survival (OS) was found for patients with mutated NPM1 without FLT3-ITD (71±4%). Outcome in patients with a high FLT3-ITD allelic ratio appeared to be very poor with OS and relapse-free survival (RFS) of 23±8% and 12±6%, respectively. Patients with wild-type NPM1 without FLT3-ITD or with a low allelic burden of FLT3-ITD were considered as intermediate-risk group because of similar OS and RFS at 5 years, in which PRT by RIC alloHSCT resulted in better OS and RFS as compared with chemotherapy (hazard ratio (HR) 0.56, P=0.022 and HR 0.50, P=0.004, respectively) or autoHSCT (HR 0.60, P=0.046 and HR 0.60, P=0.043, respectively). The lowest cumulative incidence of relapse (23±4%) was observed following MAC alloHSCT. These results suggest that alloHSCT may be preferred in patients with molecularly intermediate-risk CN-AML, while the choice of conditioning type may be personalized according to risk for non-relapse mortality.
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Trasplante de Células Madre Hematopoyéticas/métodos , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Tirosina Quinasa 3 Similar a fms/genética , Adolescente , Adulto , Femenino , Trasplante de Células Madre Hematopoyéticas/mortalidad , Humanos , Leucemia Mieloide Aguda/clasificación , Leucemia Mieloide Aguda/mortalidad , Masculino , Persona de Mediana Edad , Mutación , Nucleofosmina , Medicina de Precisión/métodos , Inducción de Remisión , Medición de Riesgo , Tasa de Supervivencia , Secuencias Repetidas en Tándem , Acondicionamiento Pretrasplante/métodos , Adulto JovenRESUMEN
Non-relapse mortality (NRM) after allogeneic hematopoietic stem cell transplantation (alloHSCT) can be predicted by the hematopoietic cell transplantation comorbidity index (HCT-CI) and the European Group for Blood and Marrow Transplantation (EBMT) score, which are composed of different parameters. We set out to integrate the parameters of both scores in patients with acute myeloid leukemia (AML) in first complete remission (CR1) receiving reduced intensity conditioning (RIC) alloHSCT. All parameters from the HCT-CI and the EBMT-score with the addition of patient and donor cytomegalovirus serology were evaluated in 812 patients by multivariable analysis with end-point NRM at 2 years. Subsequently, 16 parameters were selected based on hazard ratio >1.2, and were incorporated into a novel score, which was further internally validated by bootstrapping. Both the HCT-CI and the EBMT-score showed relatively weak predictive value, whereas the integrated score allowed to identify three clearly distinct risk groups with 2-year NRM estimates of 8±2% (low-risk), 17±2% (intermediate-risk) and 38±4% (high-risk), which also translated in prediction of overall survival. Collectively, integration of the most dominant parameters from the HCT-CI and the EBMT-score allowed to develop a simple and robust, integrated score with improved prediction of NRM for AML patients proceeding to RIC alloHSCT in CR1.
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Trasplante de Células Madre Hematopoyéticas , Leucemia Mieloide Aguda/terapia , Acondicionamiento Pretrasplante , Adulto , Anciano , Femenino , Humanos , Leucemia Mieloide Aguda/mortalidad , Masculino , Persona de Mediana Edad , Inducción de Remisión , Adulto JovenRESUMEN
The preferred type of post-remission therapy (PRT) in patients with acute myeloid leukemia (AML) in first complete remission (CR1) is a subject of continued debate, especially in patients at higher risk of nonrelapse mortality (NRM), including patients >40 years of age. We report results of a time-dependent multivariable analysis of allogenic hematopoietic stem cell transplantation (alloHSCT) (n=337) versus chemotherapy (n=271) or autologous HSCT (autoHSCT) (n=152) in 760 patients aged 40-60 years with AML in CR1. Patients receiving alloHSCT showed improved overall survival (OS) as compared with chemotherapy (respectively, 57±3% vs 40±3% at 5 years, P<0.001). Comparable OS was observed following alloHSCT and autoHSCT in patients with intermediate-risk AML (60±4 vs 54±5%). However, alloHSCT was associated with less relapse (hazard ratio (HR) 0.51, P<0.001) and better relapse-free survival (RFS) (HR 0.74, P=0.029) as compared with autoHSCT in intermediate-risk AMLs. AlloHSCT was applied following myeloablative conditioning (n=157) or reduced intensity conditioning (n=180), resulting in less NRM, but comparable outcome with respect to OS, RFS and relapse. Collectively, these results show that alloHSCT is to be preferred over chemotherapy as PRT in patients with intermediate- and poor-risk AML aged 40-60 years, whereas autoHSCT remains a treatment option to be considered in patients with intermediate-risk AML.
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Leucemia Mieloide Aguda/terapia , Adulto , Antineoplásicos/química , Supervivencia sin Enfermedad , Femenino , Trasplante de Células Madre Hematopoyéticas , Humanos , Leucemia Mieloide Aguda/mortalidad , Masculino , Persona de Mediana Edad , Análisis Multivariante , Modelos de Riesgos Proporcionales , Inducción de Remisión , Riesgo , Factores de Tiempo , Acondicionamiento Pretrasplante/métodos , Trasplante Homólogo , Resultado del TratamientoRESUMEN
Two temporally non-overlapping linearly cross-polarized 140 fs laser pulses are shown to control the spin polarization in a three-level system. Simultaneous excitation of the two excited states triggers quantum beatings originating from the interference of the wavefunctions corresponding to different spin sublevels of the states. Although the beatings are not seen in the spin densities of the excited states they are clearly observed in the magneto-optical Kerr effect. An analytical expression for the description of the beatings is obtained. Experimental results are in good agreement with theoretical predictions and demonstrate the control of beatings with attosecond resolution.
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Apendicitis/diagnóstico por imagen , Apendicitis/etiología , Situs Inversus/complicaciones , Situs Inversus/diagnóstico por imagen , Adolescente , Apendicectomía , Apendicitis/cirugía , Diagnóstico Diferencial , Femenino , Humanos , Situs Inversus/cirugía , Tomografía Computarizada por Rayos X/métodos , Resultado del TratamientoRESUMEN
Pressure-flow relationships at the entrance of the coronary circulation in the diastolic myocardium exhibit a zero-flow pressure intercept (P(int)). We tested whether this intercept is the same throughout the vascular bed. Microvascular pressure-flow relationships were therefore measured in vessels of various sizes of the maximally dilated vasculature of perfused unstimulated papillary muscle using the servo-null technique. From these relationships, P(int) were calculated with nonlinear regression. The P(int) at the level of the septal artery (diameter, 150-250 microm) was 23.2 +/- 4.4 cmH2O (n = 12). In arterioles with a diameter range between 24 and 110 microm, P(int) was 1.7 +/- 0.5 cmH2O (n = 6, P < 0.01), significantly lower than in the septal artery but significantly higher than zero, and not dependent on vessel size. In venules with the same diameters, P(int) was 1.1 +/- 1.1 cmH2O (n = 4), which was not different from zero. We conclude that, in the dilated vascular bed of the papillary muscle, two vascular waterfalls are found. The first waterfall is located in arterioles between 150 and 110 microm. The second waterfall is probably located in the small postcapillary venules.
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Presión Sanguínea/fisiología , Circulación Coronaria/fisiología , Fluoresceína-5-Isotiocianato/análogos & derivados , Animales , Arteriolas/fisiología , Dextranos , Diástole/fisiología , Masculino , Músculos Papilares/fisiología , Ratas , Ratas WistarRESUMEN
The objective of this study was to evaluate the role of right ventricular hypertrophy on developed tension (F(dev)) and contractile reserve of rat papillary muscle by using a model of monocrotaline (Mct)-induced pulmonary hypertension. Calcium handling and the influence of bicarbonate (HCO(3)(-)) were also addressed with the use of two different buffers (HCO(3)(-) and HEPES). Wistar rats were injected with either Mct (40 mg/kg sc) or vehicle control (Con). Isometrically contracting right ventricular papillary muscles were studied at 80% of the length of maximal developed force. Contractile reserve (1 - F(dev)/F(max)) was calculated from F(dev) and maximal tension (F(max)). Calcium recirculation was determined with postextrasystolic potentiation. Both groups of muscles were superfused with either HCO(3)(-) (Con-B and Mct-B, both n = 6) or HEPES (Con-H and Mct-H, both n = 6) buffer. With hypertrophy, contractions were slower but F(dev) was not changed. However, F(max) was decreased (P < 0.05). With HCO(3)(-), F(max) decreased from 23.8 +/- 6.5 mN.mm(-2) in Con-B, to 13.7 +/- 3.3 mN.mm(-2) in Mct-B. With HEPES, it decreased from 16.3 +/- 3.5 mN.mm(-2) (n = 6, Con-H) to 8.3 +/- 1.6 mN.mm(-2) (Mct-H). Contractile reserve during hypertrophy was therefore also decreased (P < 0.05). With HCO(3)(-), it decreased from 0.73 +/- 0.03 (Con-B) to 0.55 +/- 0.04 (Mct-B). With HEPES, it decreased (P < 0.001) from 0.64 +/- 0.07 (Con-H) to 0.19 +/- 0.06 (Mct-H). The recirculation fraction decreased (P < 0.05) from 0.59 +/- 0.04 in Con-B to 0.44 +/- 0.04 in Mct-B. We conclude that contractile reserve and recirculation fraction are impaired during hypertrophy, with a stronger effect under HEPES than HCO(3)(-) superfusion.
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Hipertrofia Ventricular Derecha/fisiopatología , Contracción Miocárdica/fisiología , Ácido 4,4'-Diisotiocianostilbeno-2,2'-Disulfónico/farmacología , Animales , Bicarbonatos/farmacología , Tampones (Química) , Circulación Coronaria/fisiología , HEPES/farmacología , Concentración de Iones de Hidrógeno , Hipertrofia Ventricular Derecha/inducido químicamente , Masculino , Monocrotalina , Ratas , Ratas WistarRESUMEN
We tested the hypothesis that under physiological conditions, arterioles match their diameter to the level of shear stress. Haemodynamic and anatomical data were obtained in segments of the first-order arteriole of the rat cremaster muscle. Along this segment of ~10 mm in length, local blood pressure decreased from 68 +/- 4 mmHg upstream to 54 +/- 3 mmHg downstream (n = 5). Pulse pressure decreased from 8.2 +/- 1.3 mmHg upstream to 4.1 +/- 0.6 mmHg downstream. At the same locations, an increase in arteriolar diameter was measured in vivo, from 179 +/- 4 microm upstream to 203 +/- 4 microm downstream (n = 10). In vitro pressure-diameter relations of maximally dilated vessels showed that the passive diameter was larger in downstream than upstream segments over a 15-125 mmHg pressure range (n = 18). The wall stress was similar for the upstream vs. downstream location: 266 +/- 16 vs. 260 +/- 14 mN mm-2. However, shear stress decreased from 30 +/- 5 to 21 +/- 5 dyn cm-2 (3.0 +/- 0.5 to 2.1 +/- 0.5 N m-2; n = 4) along the artery. In conclusion, these results demonstrate that shear stress is not the only factor in determining vascular calibre. We suggest that arteriolar calibre may rather depend on an interplay between shear stress and the local pressure profile.