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1.
Heart Surg Forum ; 26(2): E186-E188, 2023 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-37115005

RESUMEN

BACKGROUND: A 78-year-old male was admitted to our institute with increasing shortness of breath and decreased exercise tolerance. His increasing symptoms were not relieved with medical management. He had a complex medical history that included aortic valve replacement (AVR). Echocardiography showed a deteriorating aortic bioprosthesis with severe aortic regurgitation. METHOD: Intraoperative extraction of this prosthesis proved technically challenging and a valve in valve successfully was implanted as a salvage procedure. RESULTS: The procedure was successful, and the patient made a full recovery. CONCLUSION: Open valve in valve implantation, despite technical difficulties, may be utilized as a salvage procedure.


Asunto(s)
Estenosis de la Válvula Aórtica , Bioprótesis , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Masculino , Humanos , Anciano , Implantación de Prótesis de Válvulas Cardíacas/métodos , Diseño de Prótesis , Resultado del Tratamiento , Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/cirugía , Bioprótesis/efectos adversos
2.
J Pharmacokinet Pharmacodyn ; 46(4): 339-359, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31079322

RESUMEN

Two-pore physiologically-based pharmacokinetic (PBPK) models can be expected to describe the tissue distribution and elimination kinetics of soluble proteins, endogenous or dosed, as function of their size. In this work, we amalgamated our previous two-pore PBPK model for an inert domain antibody (dAb) in mice with the cross-species platform PBPK model for monoclonal antibodies described in literature into a unified two-pore platform that describes protein modalities of different sizes and includes neonatal Fc receptor (FcRn) mediated recycling. This unified PBPK model was parametrized for organ-specific lymph flow rates and the endosomal recycling rate constant using an extended tissue distribution time-course dataset that included an inert dAb, albumin and IgG in rats and mice. The model was evaluated by comparing the ab initio predictions for the tissue distribution and elimination properties of albumin-binding dAbs (AlbudAbsTM) in mice and rats with the experimental observations. Due to the large number of molecular species and reactions involved in large-scale PBPK models, we have also developed and deployed a MatlabTM script for automating the assembly of SimBiologyTM-based two-pore biologics PBPK models which drastically cuts the time and effort required for model building.


Asunto(s)
Albúminas/farmacocinética , Anticuerpos Monoclonales/farmacocinética , Simulación por Computador , Inmunoglobulina G/metabolismo , Modelos Biológicos , Animales , Endosomas/metabolismo , Femenino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Desnudos , Especificidad de Órganos , Ratas , Receptores Fc/genética , Especificidad de la Especie , Distribución Tisular
3.
Digestion ; 92(2): 60-5, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26183208

RESUMEN

BACKGROUND: It is unclear whether there is a shared pathway in the development of diverticular disease (DD) and potentially neoplastic colorectal lesions since both diseases are found in similar age groups and populations. AIM: To determine the association between DD and colorectal pre-neoplastic lesions in an African-American urban population. METHODS: Data from 1986 patients who underwent colonoscopy at the Howard University Hospital from January 2012 through December 2012 were analyzed for this study. The presence of diverticula and polyps was recorded using colonoscopy reports. Polyps were further classified into adenoma or hyperplastic polyp based on histopathology reports. Multiple logistic regression was done to analyze the association between DD and colonic lesions. RESULTS: Of the 1986 study subjects, 1,119 (56%) were females, 35% had DD and 56% had at least one polyp. There was a higher prevalence of polyps (70 vs. 49%; OR = 2.3; 95% CI: 1.9-2.8) and adenoma (43 vs. 25%; OR = 2.0; 95% CI: 1.7-2.5) in the diverticular vs. non-diverticula patients. Among patients who underwent screening colonoscopy, the presence of diverticulosis was associated with increased odds of associated polyps (OR = 9.9; 95% CI: 5.4-16.8) and adenoma (OR = 5.1; 95% CI: 3.4-7.8). CONCLUSION: Patients with DD are more likely to harbor colorectal lesions. These findings call for more vigilance on the part of endoscopists during colonoscopy in patients known to harbor colonic diverticula.


Asunto(s)
Adenoma/epidemiología , Negro o Afroamericano/estadística & datos numéricos , Pólipos del Colon/epidemiología , Diverticulosis del Colon/epidemiología , Lesiones Precancerosas/epidemiología , Salud Urbana/estadística & datos numéricos , Adenoma/patología , Anciano , Pólipos del Colon/patología , Colonoscopía , Estudios Transversales , Femenino , Humanos , Modelos Logísticos , Masculino , Tamizaje Masivo/métodos , Persona de Mediana Edad , Análisis Multivariante , Lesiones Precancerosas/patología , Prevalencia , Estudios Retrospectivos , Estados Unidos/epidemiología
4.
J Pharmacokinet Pharmacodyn ; 42(2): 97-109, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25577033

RESUMEN

Domain antibodies (dAbs) are the smallest antigen-binding fragments of immunoglobulins. To date, there is limited insight into the pharmacokinetics of dAbs, especially their distribution into tissues and elimination. The objective of this work was to develop a physiologically-based pharmacokinetic model to investigate the biodisposition of a non-specific dAb construct in mice. Following a single IV administration of 10 mg/kg dummy dAb protein to twenty four female mice, frequent blood samples were collected and whole body lateral sections were analyzed by quantitative whole-body autoradiography. The model is based on the two-pore hypothesis of extravasation where organ-specific isogravimetric flow rates (Jorg,ISO) and permeability-surface area products (PSorg) are expressed as linear functions of the lymph flow rate (Jorg) and the kidney compartment is modified to account for glomerular filtration of dAb. As a result, only Jorg, glomerular filtration coefficient and the combined volume of Bowman's capsule, proximal and distal renal tubules and loop of Henle were optimized by fitting simultaneously all blood and organ data to the model. Our model captures the pharmacokinetic profiles of dAb in blood and all organs and shows that extravasation into interstitial space is a predominantly diffusion-driven process. The parameter values were estimated with good precision (%RMSE ≈ 30) and low cross-correlation (R(2) < 0.2). We developed a flexible model with a limited parameter number that may be applied to other biotherapeutics after adapting for size-related effects on extravasation and renal elimination processes.


Asunto(s)
Anticuerpos de Dominio Único/metabolismo , Animales , Femenino , Tasa de Filtración Glomerular/fisiología , Túbulos Renales Distales/metabolismo , Asa de la Nefrona/metabolismo , Linfa/metabolismo , Ratones , Modelos Biológicos , Permeabilidad , Distribución Tisular
5.
Dig Dis Sci ; 59(2): 446-50, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24193352

RESUMEN

BACKGROUND: The disproportionately higher incidence of and mortality from colorectal cancer (CRC) among African Americans (AA) led the American College of Gastroenterology to recommend screening starting at age 45 in 2005. AIM: The purpose of this study was to determine the prevalence of colorectal neoplasia among 40-49-year-old inner city AA and Hispanic Americans (HA). METHODS: We reviewed the medical records of 2,435 inner city AA and HA who underwent colonoscopy regardless of indication and compared the prevalence of colorectal neoplasia between AA and HA patients. We used logistic regression models to calculate odds ratios (OR) and 95 % confidence intervals (CI). RESULTS: There were 2,163 AAs and 272 HA. There were 57 % women in both groups. A total of 158 (7 %) AA and 9 (3 %) HA (P = 0.014) underwent the procedures for CRC screening. When compared to HAs, AAs had higher prevalence of any polyp (35 vs. 18 %, OR = 2.53; 95 % CI 1.82-3.52). Overall, AA had higher prevalence of colorectal neoplasia (adenoma and cancer) when compared to HAs (16 vs. 10 %; OR = 1.68; 95 % CI 1.10-2.56). CONCLUSION: We observed a higher frequency of colorectal neoplasia among 40-49-year-old AAs as compared to HAs suggesting an increased susceptibility to CRC risk in this population.


Asunto(s)
Adenoma/etnología , Negro o Afroamericano/estadística & datos numéricos , Pólipos del Colon/etnología , Neoplasias Colorrectales/etnología , Hispánicos o Latinos/estadística & datos numéricos , Adenoma/diagnóstico , Adulto , Distribución por Edad , Factores de Edad , Distribución de Chi-Cuadrado , Pólipos del Colon/diagnóstico , Colonoscopía , Neoplasias Colorrectales/diagnóstico , Femenino , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Prevalencia , Características de la Residencia , Factores de Riesgo , Estados Unidos/epidemiología , Salud Urbana
6.
J Extra Corpor Technol ; 44(2): 53-9, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22893983

RESUMEN

This report describes the assessment of three specific safety-related specifications in the consideration of an alternate oxygenator; first the grip strength relationship between various oxygenator connectors and SMARxT tubing, second, the grip strength of various biopassive tubings and an isolated SMARxT connector, and finally, the accuracy of the arterial outlet temperature measurement. Grip strength experiments for the connections between the SMARxT tubing and the venous reservoir outlet and the oxygenator venous inlet and oxygenator arterial outlet of the Medtronic Affinity, Sorin Synthesis, Sorin Primox, and Terumo Capiox RX25 oxygenators were performed. In addition we compared the grip strength of polyvinyl chloride, Physio, Trillium, Carmeda, X-Coating, and SMARxT tubing. The accuracy of the integrated arterial outlet temperature probes was determined by comparing the temperatures measured by the integrated probe with a precision reference thermometer. Connector grip strength comparisons for the evaluation oxygenators with SMARxT tubing showed significant variation between oxygenators and connections (p = .02). Evaluation of the arterial outlet showed significant variation between evaluation oxygenators, while at the venous reservoir outlet and oxygenator inlet, there were no significant differences. Grip strength comparison data for the various tubing types demonstrated a main effect for tubing type F(5, 18) = 8.01, p = .002, eta(p)(2) = .77. Temperature accuracy measurements demonstrated that all oxygenators overread the arterial outlet temperature at 15 degrees C, whilst at temperatures > or = 25 degrees C, all oxygenators underread the arterial outlet temperature. The integrity of SMARxT tubing connection is influenced by the connector type, and may decline over time, highlighting the importance to not consider interchanging components of the bypass circuit as inconsequential.


Asunto(s)
Puente Cardiopulmonar/instrumentación , Puente Cardiopulmonar/métodos , Catéteres de Permanencia , Oxigenación por Membrana Extracorpórea/instrumentación , Fuerza de la Mano/fisiología , Oxigenadores/efectos adversos , Temperatura Corporal , Seguridad de Equipos , Humanos , Termómetros/normas , Estudios de Validación como Asunto
7.
Front Immunol ; 13: 968206, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36148231

RESUMEN

Myasthenia Gravis (MG) is mediated by autoantibodies against acetylcholine receptors that cause loss of the receptors in the neuromuscular junction. Eculizumab, a C5-inhibitor, is the only approved treatment for MG that mechanistically addresses complement-mediated loss of nicotinic acetylcholine receptors. It is an expensive drug and was approved despite missing the primary efficacy endpoint in the Phase 3 REGAIN study. There are two observations to highlight. Firstly, further C5 inhibitors are in clinical development, but other terminal pathway proteins, such as C7, have been relatively understudied as therapeutic targets, despite the potential for lower and less frequent dosing. Secondly, given the known heterogenous mechanisms of action of autoantibodies in MG, effective patient stratification in the REGAIN trial may have provided more favorable efficacy readouts. We investigated C7 as a target and assessed the in vitro function, binding epitopes and mechanism of action of three mAbs against C7. We found the mAbs were human, cynomolgus monkey and/or rat cross-reactive and each had a distinct, novel mechanism of C7 inhibition. TPP1820 was effective in preventing experimental MG in rats in both prophylactic and therapeutic dosing regimens. To enable identification of MG patients that are likely to respond to C7 inhibition, we developed a patient stratification assay and showed in a small cohort of MG patients (n=19) that 63% had significant complement activation and C7-dependent loss of AChRs in this in vitro set up. This study provides validation of C7 as a target for treatment of MG and provides a means of identifying patients likely to respond to anti-C7 therapy based on complement-activating properties of patient autoantibodies.


Asunto(s)
Antineoplásicos Inmunológicos , Miastenia Gravis Autoinmune Experimental , Receptores Nicotínicos , Animales , Anticuerpos Monoclonales/metabolismo , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Autoanticuerpos/metabolismo , Proteínas del Sistema Complemento/metabolismo , Epítopos , Humanos , Macaca fascicularis , Nicotina , Ratas , Receptores Colinérgicos
8.
Gastrointest Endosc ; 74(2): 253-61, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21549375

RESUMEN

BACKGROUND: Colonoscopy may be less efficacious in reducing colorectal cancer mortality in the proximal compared with the distal colon. A greater likelihood for missed and recurrent adenomas in the proximal colon may contribute to this phenomenon. OBJECTIVE: To examine whether a proximal adenoma is associated with the risk and location of missed and recurrent adenomas. DESIGN: Prospective. SETTING: Polyp Prevention Trial. PARTICIPANTS: A total of 1864 patients with an adenoma at baseline underwent a follow-up colonoscopy 4 years later (adenoma recurrence). Of these, 1731 underwent a clearing colonoscopy 1 year after the baseline examination (missed adenoma). MAIN OUTCOME MEASUREMENTS: Association of baseline adenoma location with the risk and location of adenomas found at colonoscopy performed 1 year and 4 years later. RESULTS: At the year 1 colonoscopy, 598 patients (34.6%) had an adenoma (missed adenoma). Compared with those with a distal-only adenoma at baseline, patients with a proximal-only adenoma at baseline were more likely to have any missed adenomas (relative risk [RR] 1.28; 95% CI, 1.09-1.49) and a proximal-only missed adenoma (RR 2.05; 95% CI, 1.49-2.80). At the year 4 colonoscopy, 733 patients (39.3%) had adenoma recurrence. Patients with a baseline proximal-only adenoma were more likely to have any adenoma recurrence (RR 1.14; 95% CI, 1.00-1.31) and a proximal-only adenoma recurrence (RR 1.52; 95% CI, 1.15-2.02). Sensitivity analyses involving missed adenomas did not materially affect the risk or location of recurrent adenomas at year 4 colonoscopy. LIMITATION: Lesions may still be missed on repeated colonoscopies. CONCLUSIONS: Missed and recurrent adenomas are more likely to be in the proximal colon.


Asunto(s)
Adenoma/diagnóstico , Colon Ascendente/patología , Colon Descendente/patología , Colon Sigmoide/patología , Colon Transverso/patología , Neoplasias del Colon/diagnóstico , Recurrencia Local de Neoplasia/diagnóstico , Anciano , Colonoscopía , Reacciones Falso Negativas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Análisis de Regresión , Factores de Riesgo
9.
J Extra Corpor Technol ; 42(2): 153-7, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20648902

RESUMEN

The use of surface modified, biocompatible tubing in cardiopulmonary bypass has been reported to decrease the inflammatory responses caused by blood contact with the non endothelial surface of poly vinyl chloride (PVC) tubing. The combination of advances in biocompatible tubing and increased affordability resulted in a change to our cardiopulmonary bypass circuit, with the Terumo Capiox SX25 oxygenator and Cobe PVC tubing being replaced with a Terumo Capiox SX25RX (with X coating) and Cobe SMARxT tubing. Prior to the introduction of the coated oxygenator, no connection problems had been evident. One unrelated disconnection involving coated tubing was reported in June 2005 to the Australian and New Zealand College of Perfusionists Perfusion Incident Reporting System. At this time we revised all of our set up protocols and the recommended actions from manufacturers. We further report three separate incidents of pump boot disconnection from the venous reservoir outlet of the oxygenator during bypass (that occurred within a 13-month period), and an outline of immediate and prospective evaluation of the probable cause. We propose that SMARxT 3/8" x 3/32" tubing should not be used on the venous outlet connector of Terumo Capiox SX25RX oxygenators. It appears as though the design of the outlet combined with the properties of SMARxT tubing may contribute to the disconnection.


Asunto(s)
Puente Cardiopulmonar/instrumentación , Puente Cardiopulmonar/métodos , Falla de Equipo , Oxigenadores , Humanos
10.
J Extra Corpor Technol ; 42(3): 191-8, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21114221

RESUMEN

The CDI 500 (Terumo Cardiovascular Systems, Ann Arbor, MI) is an in-line blood gas monitoring device that has been used in clinical practice for over a decade. Few randomized studies have evaluated the value of this device with respect to improved perfusion management. We routinely use automated continuous quality indicator programs to assess perfusion management. The aim of this study is to investigate in a prospective randomized trial the role of in-line blood gas monitoring in the improvement of blood gas management during cardiopulmonary bypass (CPB) utilizing continuous quality indicators. Patients were randomized into two groups (Control, CDI). Patients in the Control group received our standard CPB blood gas management, with intermittent blood gas results. Continuous blood gas measurements from the CDI 500 were recorded at 20-second intervals, with the perfusionist blinded to these measurements. Patients in the CDI group received standard CPB blood gas management, in addition to continuous blood gas measurements visible on the CDI 500, the alarm system activated, and the data recorded. Perfusion management for all cases was guided by institutional protocols. One hundred patients (50 in each group) were included in the study. No significant difference existed between the groups on demographic, surgical, or clinical outcomes. Blood gas levels of patients in the CDI group were able to be maintained in accordance to protocol a greater percentage of the time, e.g., pCO2 management was 2% versus 20% (p = .008); this was most notable for differences between the Control and the CDI group for pCO2 > 45 mmHg (p = .003). Practice variation determined via statistical control charts improved for both pH and pCO2, represented by a decrease in the variation associated with practice. Continuous blood gas monitoring with the CDI 500 results in significantly improved blood gas management as determined by adherence to institutional protocols.


Asunto(s)
Análisis de los Gases de la Sangre , Puente Cardiopulmonar , Monitoreo Intraoperatorio , Adulto , Anciano , Anciano de 80 o más Años , Análisis de los Gases de la Sangre/instrumentación , Procedimientos Quirúrgicos Cardíacos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
11.
Endosc Int Open ; 8(5): E617-E622, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32355879

RESUMEN

Background and study aims Negative experiences with bowel preparation are a barrier to uptake of colonoscopy. The aim of this study was to examine the impact of different flavoring of polyethylene glycol (PEG) laxatives on patient satisfaction with and adequacy of bowel preparation during colonoscopy. Patients and methods This was a single-blind (endoscopist), parallel design, randomized trial (NCT02062112) during which patients scheduled for colonoscopy were assigned to one of three groups: Group 1 (no laxative flavoring, n = 84); Group 2 (flavored entire laxative, n = 90) and Group 3 (tasted PEG with and without flavoring and decided how they want to drink the rest of the laxatives (choice group), n = 82). Patients rated their bowel preparation experience (satisfaction) and endoscopists accessed adequacy of bowel preparation during colonoscopy. Results There were no differences in patient ratings across the groups (1, 2 and 3) in taste of the laxatives ( P  = 0.67), ease of drinking ( P  = 0.53), and overall experience of bowel preparation process ( P  = 0.18). However, higher percentage of patients in the choice group would want the same laxative again if they were going to have a repeat colonoscopy in the future (72.5 % vs 81.3 % vs 88.9 %, P  = 0.04). Surprisingly, adequacy of bowel preparation was highest among patients who drank their PEG unflavored (89.3 % vs 80 % vs 75.5 %, P  = 0.07) and the had highest rates of adenoma detection (40.5 % vs 23.3 vs 39.0, P  = 0.03). Conclusions There were no differences in overall tolerability of bowel preparation by patterns of flavoring of PEG. Those who drank unflavored PEG were less satisfied but had better clinical outcome, suggesting minimum justification effect in bowel preparation process.

12.
Neurobiol Aging ; 89: 132-141, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31324405

RESUMEN

White matter hyperintensities (WMHs) are a risk factor for cognitive decline. Physical activity (PA) is associated with lower WMH. Whether long-term exposure to PA programs has beneficial effects on WMH progression in older adults with memory complaints and comorbid conditions has had limited exploration. This study explored whether a 24-month moderate-intensity PA intervention can delay the progression of WMH and hippocampus loss in older adults at risk for cognitive decline. Data acquired on magnetic resonance imaging were used to measure the progression of WMH and hippocampus loss. The results of this study showed no effect of intervention on either the primary outcome measure "WMH" or the secondary outcome measure "hippocampal volume." In addition, neither beta amyloid status nor the adherence to the intervention had any effect on the outcome. In this cohort of subjective memory complaints and mild cognitive impairment participants with vascular risk factors, there was no effect of long-term moderate-intensity PA on WMH or hippocampal loss.


Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/patología , Ejercicio Físico/fisiología , Resultados Negativos , Servicios Preventivos de Salud/métodos , Evaluación de Programas y Proyectos de Salud , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/prevención & control , Disfunción Cognitiva/prevención & control , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Tomografía de Emisión de Positrones , Riesgo , Factores de Tiempo
13.
Nat Med ; 26(4): 519-528, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32284611

RESUMEN

The primary human immunodeficiency virus (HIV) reservoir is composed of resting memory CD4+ T cells, which often express the immune checkpoint receptors programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4), which limit T cell activation via synergistic mechanisms. Using simian immunodeficiency virus (SIV)-infected, long-term antiretroviral therapy (ART)-treated rhesus macaques, we demonstrate that PD-1, CTLA-4 and dual CTLA-4/PD-1 immune checkpoint blockade using monoclonal antibodies is well tolerated, with evidence of bioactivity in blood and lymph nodes. Dual blockade was remarkably more effective than PD-1 blockade alone in enhancing T cell cycling and differentiation, expanding effector-memory T cells and inducing robust viral reactivation in plasma and peripheral blood mononuclear cells. In lymph nodes, dual CTLA-4/PD-1 blockade, but not PD-1 alone, decreased the total and intact SIV-DNA in CD4+ T cells, and SIV-DNA and SIV-RNA in B cell follicles, a major site of viral persistence during ART. None of the tested interventions enhanced SIV-specific CD8+ T cell responses during ART or viral control after ART interruption. Thus, despite CTLA-4/PD-1 blockade inducing robust latency reversal and reducing total levels of integrated virus, the degree of reservoir clearance was still insufficient to achieve viral control. These results suggest that immune checkpoint blockade regimens targeting PD-1 and/or CTLA-4, if performed in people living with HIV with sustained aviremia, are unlikely to induce HIV remission in the absence of additional interventions.


Asunto(s)
Antirretrovirales/uso terapéutico , Anticuerpos Monoclonales/farmacología , Antígeno CTLA-4/inmunología , Receptor de Muerte Celular Programada 1/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Virus de la Inmunodeficiencia de los Simios/efectos de los fármacos , Activación Viral/efectos de los fármacos , Animales , Antirretrovirales/inmunología , Anticuerpos Monoclonales/sangre , Anticuerpos Monoclonales/farmacocinética , Antígeno CTLA-4/antagonistas & inhibidores , Macaca mulatta , Masculino , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Síndrome de Inmunodeficiencia Adquirida del Simio/sangre , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/fisiología , Carga Viral/efectos de los fármacos , Viremia/inducido químicamente , Replicación Viral/efectos de los fármacos , Privación de Tratamiento
14.
J Mol Biol ; 349(3): 608-20, 2005 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-15878177

RESUMEN

Yeast Hho1p contains two domains, GI and GII, that are homologous to the single globular domain of the linker histone H1 (GH1). We showed previously that the isolated GI and GII domains have different structural stabilities and functional properties. GI, like GH1 and the related GH5, is stably folded at low ionic strength (10 mM sodium phosphate) and gives strong protection of chromatosome-length DNA ( approximately 166 bp) during micrococcal nuclease digestion of chromatin. GII is intrinsically unfolded in 10 mM sodium phosphate and gives weak chromatosome protection, but in 250 mM sodium phosphate has a structure very similar to that of GI as determined by NMR spectroscopy. We now show that the loop between helices II and III in GII is the cause of both its instability and its inability to confer strong chromatosome protection. A mutant GII, containing the loop of GI, termed GII-L, is stable in 10 mM sodium phosphate and is as effective as GI in chromatosome protection. Two GII mutants with selected mutations within the original loop were also slightly more stable than GII. In GII, two of the four basic residues conserved at the second DNA binding site ("site II") on the globular domain of canonical linker histones, and in GI, are absent. Introduction of the two "missing" site II basic residues into GII or GII-L destabilised the protein and led to decreased chromatosome protection relative to the protein without the basic residues. In general, the ability to confer chromatosome protection in vitro is closely related to structural stability (the relative population of structured and unstructured states). We have determined the structure of GII-L by NMR spectroscopy. GII-L is very similar to GII folded in 250 mM sodium phosphate, with the exception of the substituted loop region, which, as in GI, contains a single helical turn.


Asunto(s)
Histonas/química , Histonas/metabolismo , Ingeniería de Proteínas , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Secuencia de Aminoácidos , Simulación por Computador , Histonas/genética , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Análisis Espectral
15.
World J Gastroenterol ; 22(28): 6539-46, 2016 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-27605888

RESUMEN

AIM: To study the accuracy of using high definition (HD) scope with narrow band imaging (NBI) vs standard white light colonoscope without NBI (ST), to predict the histology of the colon polyps, particularly those < 1 cm. METHODS: A total of 147 African Americans patients who were referred to Howard University Hospital for screening or, diagnostic or follow up colonoscopy, during a 12-mo period in 2012 were prospectively recruited. Some patients had multiple polyps and total number of polyps was 179. Their colonoscopies were performed by 3 experienced endoscopists who determined the size and stated whether the polyps being removed were hyperplastic or adenomatous polyps using standard colonoscopes or high definition colonoscopes with NBI. The histopathologic diagnosis was reported by pathologists as part of routine care. RESULTS: Of participants in the study, 55 (37%) were male and median (interquartile range) of age was 56 (19-80). Demographic, clinical characteristics, past medical history of patients, and the data obtained by two instruments were not significantly different and two methods detected similar number of polyps. In ST scope 89% of polyps were < 1 cm vs 87% in HD scope (P = 0.7). The ST scope had a positive predictive value (PPV) and positive likelihood ratio (PLR) of 86% and 4.0 for adenoma compared to 74% and 2.6 for HD scope. There was a trend of higher sensitivity for HD scope (68%) compare to ST scope (53%) with almost the same specificity. The ST scope had a PPV and PLR of 38% and 1.8 for hyperplastic polyp (HPP) compared to 42% and 2.2 for HD scope. The sensitivity and specificity of two instruments for HPP diagnosis were similar. CONCLUSION: Our results indicated that HD scope was more sensitive in diagnosis of adenoma than ST scope. Clinical diagnosis of HPP with either scope is less accurate compared to adenoma. Colonoscopy diagnosis is not yet fully matched with pathologic diagnosis of colon polyp. However with the advancement of both imaging and training, it may be possible to increase the sensitivity and specificity of the scopes and hence save money for eliminating time and the cost of Immunohistochemistry/pathology.


Asunto(s)
Adenoma/diagnóstico por imagen , Pólipos Adenomatosos/diagnóstico por imagen , Pólipos del Colon/diagnóstico por imagen , Colonoscopía , Neoplasias Colorrectales/diagnóstico por imagen , Imagen de Banda Estrecha , Adenoma/patología , Pólipos Adenomatosos/patología , Adulto , Negro o Afroamericano , Anciano , Anciano de 80 o más Años , Pólipos del Colon/patología , Colonoscopios , Neoplasias Colorrectales/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sensibilidad y Especificidad , Adulto Joven
16.
J Extra Corpor Technol ; 37(1): 32-7, 2005 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15804154

RESUMEN

Oxygenator arterial outlet blood temperature is routinely measured in the cardiopulmonary bypass (CPB) circuit as a surrogate for the temperature of the arterial blood delivered to sensitive organs such as the brain. The aim of this study was to evaluate the accuracy of the temperature thermistors used in the Terumo Capiox SX25 oxygenator and to compare the temperature measured at the outlet of the oxygenator using the Capiox CX*TL Luer Thermistor with temperatures measured at distal sites. Five experimental stages were performed in vitro to achieve this aim. Under our experimental conditions, the luer thermistors accurately measured the temperature as referenced by a precision thermometer. In the CPB circuit, the difference between arterial outlet and reference thermometer temperature varied with outlet temperature over-reading at low temperatures and under reading at high temperatures. There was negligible heat loss (-0.4+/-0.1degrees C) measured at 4.5 m from the arterial outlet. The Terumo Capiox CX*TL Luer Thermistor is an accurate and reliable instrument for measuring temperature when incorporated into the Capiox Oxygenator. The accuracy in the measurement of temperature using these thermistors is affected by the thermistor immersion depth. Under reading of the arterial blood temperature by approximately 0.5 degrees C should be considered at normothermic temperatures, to avoid exceeding the maximum arterial blood temperature as described by institutional protocols. The accuracy of blood temperature measurements should be considered for all oxygenator arterial outlet temperature probes.


Asunto(s)
Temperatura Corporal , Puente Cardiopulmonar/instrumentación , Oxigenación por Membrana Extracorpórea/instrumentación , Oxigenadores de Membrana/normas , Termómetros/normas , Seguridad de Equipos , Humanos , Ensayo de Materiales , Monitoreo Fisiológico , Control de Calidad , Valores de Referencia
17.
PLoS One ; 10(9): e0137065, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26352810

RESUMEN

Tumour Necrosis Factor-α (TNF-α) inhibition has been transformational in the treatment of patients with inflammatory disease, e.g. rheumatoid arthritis. Intriguingly, TNF-α signals through two receptors, TNFR1 and TNFR2, which have been associated with detrimental inflammatory and beneficial immune-regulatory processes, respectively. To investigate if selective TNFR1 inhibition might provide benefits over pan TNF-α inhibition, tools to investigate the potential impact of pharmacological intervention are needed. Receptor-deficient mice have been very insightful, but are not reversible and could distort receptor cross-talk, while inhibitory anti-TNFR1 monoclonal antibodies have a propensity to induce receptor agonism. Therefore, we set out to characterise a monovalent anti-TNFR1 domain antibody (dAb) formatted for in vivo use. The mouse TNFR1 antagonist (DMS5540) is a genetic fusion product of an anti-TNFR1 dAb with an albumin-binding dAb (AlbudAb). It bound mouse TNFR1, but not human TNFR1, and was an antagonist of TNF-α-mediated cytotoxicity in a L929 cell assay. Surprisingly, the dAb did not compete with TNF-α for TNFR1-binding. This was supported by additional data showing the anti-TNFR1 epitope mapped to a single residue in the first domain of TNFR1. Pharmacokinetic studies of DMS5540 in mice over three doses (0.1, 1.0 and 10 mg/kg) confirmed extended in vivo half-life, mediated by the AlbudAb, and demonstrated non-linear clearance of DMS5540. Target engagement was further confirmed by dose-dependent increases in total soluble TNFR1 levels. Functional in vivo activity was demonstrated in a mouse challenge study, where DMS5540 provided dose-dependent inhibition of serum IL-6 increases in response to bolus mouse TNF-α injections. Hence, DMS5540 is a potent mouse TNFR1 antagonist with in vivo pharmacokinetic and pharmacodynamic properties compatible with use in pre-clinical disease models and could provide a useful tool to dissect the individual contributions of TNFR1 and TNFR2 in homeostasis and disease.


Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Artritis Reumatoide/terapia , Receptores Tipo I de Factores de Necrosis Tumoral/inmunología , Proteínas Recombinantes de Fusión/administración & dosificación , Anticuerpos de Dominio Único/administración & dosificación , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Anticuerpos Monoclonales/genética , Anticuerpos Monoclonales/farmacocinética , Artritis Reumatoide/sangre , Artritis Reumatoide/inmunología , Línea Celular , Epítopos/efectos de los fármacos , Epítopos/inmunología , Humanos , Interleucina-6/sangre , Ratones , Receptores Tipo I de Factores de Necrosis Tumoral/antagonistas & inhibidores , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Transducción de Señal , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/inmunología
18.
World J Gastrointest Pharmacol Ther ; 6(3): 84-8, 2015 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-26261736

RESUMEN

AIM: To examine whether non-alcoholic beverage intake preferences can guide polyethylene glycol (PEG)-based bowel laxative preparation selection for patients. METHODS: We conducted eight public taste test sessions using commercially procured (A) unflavored PEG, (B) citrus flavored PEG and (C) PEG with ascorbate (Moviprep). We collected characteristics of volunteers including their beverage intake preferences. The volunteers tasted the laxatives in randomly assigned orders and ranked the laxatives as 1(st), 2(nd), and 3(rd) based on their taste preferences. Our primary outcome is the number of 1(st) place rankings for each preparation. RESULTS: A total of 777 volunteers completed the study. Unflavored PEG was ranked as 1(st) by 70 (9.0%), flavored PEG by 534 (68.7%) and PEG with ascorbate by 173 (22.3%) volunteers. Demographic, lifestyle characteristics and beverage intake patterns for coffee, tea, and carbonated drinks did not predict PEG-based laxative preference. CONCLUSION: Beverage intake pattern was not a useful guide for PEG-based laxative preference. It is important to develop more tolerable and affordable bowel preparation laxatives for colonoscopy. Also, patients should taste their PEG solution with and without flavoring before flavoring the entire gallon as this may give them more opportunity to pick a pattern that may be more tolerable.

19.
FEBS Lett ; 544(1-3): 199-205, 2003 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-12782316

RESUMEN

Previous work has shown that the base sequence of the DNA segment immediately upstream of the -10 hexamer at bacterial promoters (the extended -10 element) can make a significant contribution to promoter strength. Guided by recently published structural information, we used alanine scanning and suppression mutagenesis of Region 2.4 and Region 3.0 of the Escherichia coli RNA polymerase sigma(70) subunit to identify amino acid sidechains that play a role in recognition of this element. Our study shows that changes in these regions of the sigma(70) subunit can affect the recognition of different extended -10 element sequences.


Asunto(s)
ARN Polimerasas Dirigidas por ADN/química , ARN Polimerasas Dirigidas por ADN/genética , Escherichia coli/enzimología , Factor sigma/química , Factor sigma/genética , Alanina/química , Alanina/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis , Mutación , Regiones Promotoras Genéticas , Unión Proteica , Estructura Terciaria de Proteína , Transcripción Genética
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