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1.
Catheter Cardiovasc Interv ; 104(2): 330-342, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38736248

RESUMO

BACKGROUND: Left atrial appendage occlusion (LAAO) with WATCHMAN currently requires preprocedural imaging, general anesthesia, and inpatient overnight admission. We sought to facilitate simplification of LAAO. AIMS: We describe and compare SOLO-CLOSE (single-operator LAA occlusion utilizing conscious sedation TEE, lack of outpatient pre-imaging, and same-day expedited discharge) with the conventional approach (CA). METHODS: A single-center retrospective analysis of 163 patients undergoing LAAO between January 2017 and April 2022 was conducted. The SOLO-CLOSE protocol was enacted on December 1, 2020. Before this date, we utilized the CA. The primary efficacy endpoint was defined as successful LAAO with ≤5 mm peri-device leak at time of closure. The primary safety endpoint was the composite incidence of all-cause deaths, any cerebrovascular accident (CVA), device embolization, pericardial effusion, or major postprocedure bleeding within 7 days of the index procedure. Procedure times, 7-day readmission rates, and cost analytics were collected as well. RESULTS: Baseline characteristics were similar in both cohorts. Congestive heart failure (37.5% vs. 11.1%) and malignancy (28.8% vs. 12.5%) were higher in SOLO-CLOSE. Median CHA2D2SVASc score was 5 in both cohorts. The primary efficacy endpoint was met 100% in both cohorts. Primary safety endpoint was similar between cohorts (p = 0.078). Mean procedure time was 30 min shorter in SOLO-CLOSE (p < 0.01). Seven-day readmissions for SOLO-CLOSE was zero. After SOLO-CLOSE implementation, there was a 188% increase in positive contribution margin per case. CONCLUSIONS: The SOLO-CLOSE methodology offers similar efficacy and safety when compared to the CA, while improving clinical efficiency, reducing procedural times, and increasing economic benefit.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Cateterismo Cardíaco , Sedação Consciente , Ecocardiografia Transesofagiana , Alta do Paciente , Humanos , Feminino , Estudos Retrospectivos , Masculino , Idoso , Apêndice Atrial/diagnóstico por imagem , Apêndice Atrial/fisiopatologia , Resultado do Tratamento , Sedação Consciente/efeitos adversos , Fatores de Tempo , Fibrilação Atrial/terapia , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/diagnóstico por imagem , Cateterismo Cardíaco/efeitos adversos , Cateterismo Cardíaco/instrumentação , Idoso de 80 Anos ou mais , Fatores de Risco , Readmissão do Paciente , Pessoa de Meia-Idade , Análise Custo-Benefício
2.
Front Toxicol ; 4: 933572, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36310694

RESUMO

Background: Bisphenol S (BPS) is among the most commonly used substitutes for Bisphenol A (BPA), an endocrine disrupting chemical used as a plasticizer in the manufacture of polycarbonate plastics and epoxy resins. Bisphenols interfere with estrogen receptor (ER) signaling, which modulates vascular function through stimulation of nitric oxide (NO) production via endothelial nitric oxide synthase (eNOS). BPS can cross into the placenta and accumulates in the fetal compartment to a greater extent than BPA, potentially interfering with key developmental events. Little is known regarding the developmental impact of exposure to BPA substitutes, particularly with respect to the vasculature. Objective: To determine if prenatal BPS exposure influences vascular health in adulthood. Methods: At the time of mating, female C57BL/6 dams were administered BPS (250 nM) or vehicle control in the drinking water, and exposure continued during lactation. At 12-week of age, mesenteric arteries were excised from male and female offspring and assessed for responses to an endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside, SNP) vasodilator. Endothelium-dependent dilation was measured in the presence or absence of L-NAME, an eNOS inhibitor. To further explore the role of NO and ER signaling, wire myography was used to assess ACh responses in aortic rings after acute exposure to BPS in the presence or absence of L-NAME or an ER antagonist. Results: Increased ACh dilation and increased sensitivity to Phe were observed in microvessels from BPS-exposed females, while no changes were observed in male offspring. Differences in ACh-induced dilation between control or BPS-exposed females were eliminated with L-NAME. Increased dilatory responses to ACh after acute BPS exposure were observed in aortic rings from female mice only, and differences were eliminated with inhibition of eNOS or inhibition of ER. Conclusion: Prenatal BPS exposure leads to persistent changes in endothelium-dependent vascular function in a sex-specific manner that appears to be modulated by interaction of BPS with ER signaling.

3.
Hypertens Res ; 44(8): 941-954, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33972751

RESUMO

Dietary intake of the heavy metal cadmium (Cd2+) is implicated in hypertension, but potassium supplementation reportedly mitigates hypertension. This study aims to elucidate the hypertensive mechanism of Cd2+. Vascular reactivity and protein expression were assessed in Cd2+-exposed rats for 8 weeks to determine the calcium-handling effect of Cd2+ and the possible signaling pathways and mechanisms involved. Cd2+ induced hypertension in vivo by significantly (p < 0.001) elevating systolic blood pressure (160 ± 2 and 155 ± 1 vs 120 ± 1 mm Hg), diastolic blood pressure (119 ± 2 and 110 ± 1 vs 81 ± 1 mm Hg), and mean arterial pressure (133 ± 2 and 125 ± 1 vs 94 ± 1 mm Hg) (SBP, DBP, and MAP, respectively), while potassium supplementation protected against elevation of these parameters. The mechanism involved augmentation of the phosphorylation of renal myosin light chain phosphatase targeting subunit 1 (MYPT1) at threonine 697 (T697) (2.58 ± 0.36 vs 1 ± 0) and the expression of p44 mitogen-activated protein kinase (MAPK) (1.78 ± 0.20 vs 1 ± 0). While acetylcholine (ACh)-induced relaxation was unaffected, 5 mg/kg b.w. Cd2+ significantly (p < 0.001) attenuated phenylephrine (Phe)-induced contraction of the aorta, and 2.5 mg/kg b.w. Cd2+ significantly (p < 0.05) augmented sodium nitroprusside (SNP)-induced relaxation of the aorta. These results support the vital role of the kidney in regulating blood pressure changes after Cd2+ exposure, which may be a key drug target for hypertension management. Given the differential response to Cd2+, it is apparent that its hypertensive effects could be mediated by myosin light chain phosphatase (MLCP) inhibition via phosphorylation of renal MYPT1-T697 and p44 MAPK. Further investigation of small arteries and the Rho-kinase/MYPT1 interaction is recommended.


Assuntos
Cádmio , Hipertensão , Animais , Cádmio/toxicidade , Hipertensão/induzido quimicamente , Rim/metabolismo , Proteínas Quinases Ativadas por Mitógeno , Fosfatase de Miosina-de-Cadeia-Leve/metabolismo , Fosforilação , Ratos , Treonina , Quinases Associadas a rho/metabolismo
4.
J Surg Educ ; 77(1): 74-81, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31422019

RESUMO

OBJECTIVE: There is a lack of literature describing how competitive surgical fellowships are, especially across specialties. Such information would be valuable to prospective candidates, especially as immediate postresidency subspecialty training becomes the norm for general surgery. Match-rates alone may be misleading indicators as programs may not fill positions with unqualified applicants. We propose a simple metric to analyze the competitiveness of various surgical subspecialties to each other and themselves over time. DESIGN: Retrospective cohort study. The Competitive Index is defined as the percentage of filled programs within each specialty divided by the match-rate for that specialty. For ease of comparison, a Normalized Competitive Index (NCI) was developed, normalizing the metric for all specialties in that year to a value of 1. SETTING: The National Resident Matching Program, The Fellowship Council, and the San Francisco Match publicly available match data from 2009 to 2018. PARTICIPANTS: General Surgery Associated Fellowship Applicants (Abdominal Transplant, Colorectal, Surgical Oncology, Minimally Invasive Surgery, Pediatric, Plastic, Critical Care, Thoracic, and Vascular). RESULTS: The overall match rate for all specialties was 74.6% and 84.0% of all programs were filled. Over the past decade, pediatric surgery was significantly more competitive than other specialties (NCI 1.67, p < 0.0001), while surgical critical care (NCI 0.58, p < 0.0001) and vascular (NCI 0.90, p < 0.0492) were significantly less competitive. When comparing the NCI within each specialty from the first 5 years (2009-2013) to the last 5 years, (2014-2018), surgical critical care (NCI 0.54 vs. 0.62, p = 0.0462) and thoracic (NCI 0.74 vs. 1.08, p=0.0025) became significantly more competitive, while transplant (NCI 1.10 vs. 0.92, p = 0.0343) and colorectal (NCI 1.32 vs. 1.09, p = 0.0021) became significantly less competitive. CONCLUSION: The NCI is a metric which might be useful to prospective applicants and which could be provided annually by organizations sponsoring fellowship matching processes. Further research must be performed to establish what defines a qualified applicant in each specialty.


Assuntos
Bolsas de Estudo , Internato e Residência , Criança , Educação de Pós-Graduação em Medicina , Humanos , Estudos Prospectivos , Estudos Retrospectivos , São Francisco , Estados Unidos
6.
Microcirculation ; 24(3)2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28231612

RESUMO

OBJECTIVE: Mesenteric lymphatic vessel pumping, important to propel lymph and immune cells from the intestinal interstitium to the mesenteric lymph nodes, is compromised during intestinal inflammation. The objective of this study was to test the hypothesis that the pro-inflammatory cytokine TNF-α, is a significant contributor to the inflammation-induced lymphatic contractile dysfunction, and to determine its mode of action. METHODS: Contractile parameters were obtained from isolated rat mesenteric lymphatic vessels mounted on a pressure myograph after 24-hours incubation with or without TNF-α. Various inhibitors were administered, and quantitative real-time PCR, Western blotting, and immunofluorescence confocal imaging were applied to characterize the mechanisms involved in TNF-α actions. RESULTS: Vessel contraction frequency was significantly decreased after TNF-α treatment and could be restored by selective inhibition of NF-кB, iNOS, guanylate cyclase, and ATP-sensitive K+ channels. We further demonstrated that NF-кB inhibition also suppressed the significant increase in iNOS mRNA observed in TNF-α-treated lymphatic vessels and that TNF-α treatment favored the nuclear translocation of the p65 NF-κB subunit. CONCLUSIONS: These findings suggest that TNF-α decreases mesenteric lymphatic contractility by activating the NF-κB-iNOS signaling pathway. This mechanism could contribute to the alteration of lymphatic pumping reported in intestinal inflammation.


Assuntos
Vasos Linfáticos/fisiopatologia , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Transdução de Sinais , Fator de Necrose Tumoral alfa/farmacologia , Animais , Inflamação/metabolismo , Mesentério/irrigação sanguínea , Contração Muscular/efeitos dos fármacos , Ratos
7.
Hernia ; 19(2): 197-205, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25081838

RESUMO

PURPOSE: Biologic meshes are being used with increasing frequency to repair contaminated abdominal wall defects despite high long-term recurrence and infection rates associated with their use. Recent clinical reports describing the success of lightweight, macroporous synthetic meshes in contaminated ventral hernia repairs have led some surgeons to challenge the belief that synthetics are contraindicated in contaminated fields. We aimed to determine whether a frequently used biologic mesh (Strattice(TM)) is more resistant to bacterial colonization than macroporous synthetic mesh (Parietex(TM) Progrip(TM)) after inoculation with two common pathogens. METHODS: Rats (n = 48) were implanted subcutaneously with Strattice(TM) or Progrip(TM). Meshes were inoculated with sterile saline or a suspension containing 10(6) colony-forming units of Staphylococcus aureus or Escherichia coli prior to wound closure (n = 8 per subgroup). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses. RESULTS: Progrip(TM) demonstrated superior bacterial clearance compared to Strattice(TM) (E. coli, 88 vs. 17% clearance, p = 0.03; S. aureus, 75 vs. 50%, p = 0.61; combined bacterial strains, 81 vs. 36%, p = 0.02; respectively). In the Strattice(TM) group, severely degraded meshes were observed in 100% of animals inoculated with E. coli (but 0% inoculated with S. aureus). In contrast, all Progrip(TM) meshes remained intact regardless of inoculum. Scores for neovascularization were higher in the synthetic group irrespective of contamination (p < 0.05). CONCLUSIONS: Biologic meshes may not be more resistant to bacterial colonization than reduced-weight synthetics, and their resistance may differ in response to different pathogens. The routine use of biologics in contaminated ventral hernia repair should be questioned, particularly in the presence of E. coli.


Assuntos
Infecções Bacterianas/diagnóstico , Escherichia coli , Teste de Materiais , Próteses e Implantes/microbiologia , Staphylococcus aureus , Telas Cirúrgicas/microbiologia , Animais , Bioprótese/microbiologia , Colágeno , Análise de Falha de Equipamento , Infecções por Escherichia coli/diagnóstico , Masculino , Poliésteres , Ratos , Ratos Sprague-Dawley , Infecções Estafilocócicas/diagnóstico
8.
J Mol Cell Cardiol ; 72: 364-73, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24787473

RESUMO

Endothelial dysfunction is a common early pathogenic event in patients with type 2 diabetes (T2D) who exhibit cardiovascular disease. In the present study, we have examined the effect of SKA-31, a positive modulator of endothelial Ca(2+)-activated K(+) (KCa) channels, on total coronary flow in isolated hearts from Goto-Kakizaki rats, a non-obese model of T2D exhibiting metabolic syndrome. Total coronary flow and left ventricular developed pressure were monitored simultaneously in isolated, spontaneously beating Langendorff-perfused hearts. Acute administrations of bradykinin (BK) or adenosine (ADO) increased coronary flow, but responses were significantly blunted in diabetic hearts at 10-12 and 18-20weeks of age compared with age-matched Wistar controls, consistent with the presence of endothelial dysfunction. In contrast, SKA-31 dose-dependently (0.01-5µg) increased total coronary flow to comparable levels in both control and diabetic rat hearts at both ages. Flow responses to sodium nitroprusside were not different between control and diabetic hearts, suggesting normal arterial smooth muscle function. Importantly, exposure to a sub-threshold concentration of SKA-31 (i.e. 0.3µM) rescued the impaired BK and ADO-evoked vasodilatory responses in diabetic hearts. Endothelial KCa channel activators may thus help to preserve coronary flow in diabetic myocardium.


Assuntos
Benzotiazóis/farmacologia , Circulação Coronária/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Endotélio Vascular/efeitos dos fármacos , Coração/efeitos dos fármacos , Canais de Potássio Cálcio-Ativados/agonistas , Adenosina/farmacologia , Fatores Etários , Animais , Bradicinina/farmacologia , Vasos Coronários/efeitos dos fármacos , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Diabetes Mellitus Tipo 2/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Coração/fisiopatologia , Bombas de Infusão , Masculino , Nitroprussiato/farmacologia , Técnicas de Cultura de Órgãos , Canais de Potássio Cálcio-Ativados/metabolismo , Ratos , Ratos Wistar
10.
J Physiol ; 588(Pt 22): 4519-37, 2010 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-20876197

RESUMO

Cerebral vascular smooth muscle contractility plays a crucial role in controlling arterial diameter and, thereby, blood flow regulation in the brain. A number of K(+) channels have been suggested to contribute to the regulation of diameter by controlling smooth muscle membrane potential (E(m)) and Ca(2+) influx. Previous studies indicate that stromatoxin (ScTx1)-sensitive, Kv2-containing channels contribute to the control of cerebral arterial diameter at 80 mmHg, but their precise role and molecular composition were not determined. Here, we tested if Kv2 subunits associate with 'silent' subunits from the Kv5, Kv6, Kv8 or Kv9 subfamilies to form heterotetrameric channels that contribute to control of diameter of rat middle cerebral arteries (RMCAs) over a range of intraluminal pressure from 10 to 100 mmHg. The predominant mRNAs expressed by RMCAs encode Kv2.1 and Kv9.3 subunits. Co-localization of Kv2.1 and Kv9.3 proteins at the plasma membrane of dissociated single RMCA myocytes was detected by proximity ligation assay. ScTx1-sensitive native current of RMCA myocytes and Kv2.1/Kv9.3 currents exhibited functional identity based on the similarity of their deactivation kinetics and voltage dependence of activation that were distinct from those of homomultimeric Kv2.1 channels. ScTx1 treatment enhanced the myogenic response of pressurized RMCAs between 40 and 100 mmHg, but this toxin also caused constriction between 10 and 40 mmHg that was not previously observed following inhibition of large conductance Ca(2+)-activated K(+) (BK(Ca)) and Kv1 channels. Taken together, this study defines the molecular basis of Kv2-containing channels and contributes to our understanding of the functional significance of their expression in cerebral vasculature. Specifically, our findings provide the first evidence of heteromultimeric Kv2.1/Kv9.3 channel expression in RMCA myocytes and their distinct contribution to control of cerebral arterial diameter over a wider range of E(m) and transmural pressure than Kv1 or BK(Ca) channels owing to their negative range of voltage-dependent activation.


Assuntos
Artérias Cerebrais/fisiologia , Canal de Potássio KCNQ3/fisiologia , Peptídeos/fisiologia , Multimerização Proteica/fisiologia , Subunidades Proteicas/fisiologia , Canais de Potássio Shab/fisiologia , Vasoconstrição/fisiologia , Animais , Células HEK293 , Humanos , Canal de Potássio KCNQ3/química , Masculino , Subunidades Proteicas/química , Ratos , Ratos Sprague-Dawley , Canais de Potássio Shab/antagonistas & inibidores , Canais de Potássio Shab/química , Venenos de Aranha
11.
J Biol Chem ; 284(24): 16562-16574, 2009 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-19389710

RESUMO

Vascular smooth muscle Kv1 delayed rectifier K+ channels (KDR) containing Kv1.2 control membrane potential and thereby regulate contractility. Vasodilatory agonists acting via protein kinase A (PKA) enhance vascule smooth muscle Kv1 activity, but the molecular basis of this regulation is uncertain. We characterized the role of a C-terminal phosphorylation site, Ser-449, in Kv1.2 expressed in HEK 293 cells by biochemical and electrophysiological methods. We found that 1) in vitro phosphorylation of Kv1.2 occurred exclusively at serine residues, 2) one major phosphopeptide that co-migrated with 449pSASTISK was generated by proteolysis of in vitro phosphorylated Kv1.2, 3) the peptide 445KKSRSASTISK exhibited stoichiometric phosphorylation by PKA in vitro, 4) matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectroscopy (MS) and MS/MS confirmed in vitro Ser-449 phosphorylation by PKA, 5) in situ phosphorylation at Ser-449 was detected in HEK 293 cells by MALDI-TOF MS followed by MS/MS. MIDAS (multiple reaction monitoring-initiated detection and sequencing) analysis revealed additional phosphorylated residues, Ser-440 and Ser-441, 6) in vitro 32P incorporation was significantly reduced in Kv1.2-S449A, Kv1.2-S449D, and Kv1.2-S440A/S441A/S449A mutant channels, but Kv1.2-S440A/S441A was identical to wild-type Kv1.2 (Kv1.2-WT), and 7) bath applied 8-Br-cAMP or dialysis with PKA catalytic subunit (cPKA) increased Kv1.2-WT but not Kv1.2-S449A current amplitude. cPKA increased Kv1.2-WT current in inside-out patches. Rp-CPT-cAMPS reduced Kv1.2-WT current, blocked the increase due to 8-Br-cAMP, but had no effect on Kv1.2-S449A. cPKA increased current due to double mutant Kv1.2-S440A/S441A but had no effect on Kv1.2-S449D or Kv1.2-S440A/S441A/S449A. We conclude that Ser-449 in Kv1.2 is a site of PKA phosphorylation and a potential molecular mechanism for Kv1-containing KDR channel modulation by agonists via PKA activation.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Canal de Potássio Kv1.2/genética , Canal de Potássio Kv1.2/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Humanos , Rim/citologia , Canal de Potássio Kv1.2/química , Potenciais da Membrana/fisiologia , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Técnicas de Patch-Clamp , Fosforilação/fisiologia , Estrutura Terciária de Proteína , Coelhos , Serina/metabolismo
12.
Circ Res ; 101(10): 1030-8, 2007 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-17872462

RESUMO

The Na+/Ca2+ exchanger (NCX) is increasingly recognized as a physiological mediator of Ca2+ influx and significantly contributes to salt-sensitive hypertension. We recently reported that Ca2+ influx by the NCX (1) is the primary mechanism of Ca2+ entry in purinergically stimulated rat aorta smooth muscle cells and (2) requires functional coupling with transient receptor potential channel 6 nonselective cation channels. Using the Na+ indicator CoroNa Green, we now directly observed and characterized the localized cytosolic [Na+] ([Na+]i) elevations that have long been hypothesized to underlie physiological NCX reversal but that have never been directly shown. Stimulation of rat aorta smooth muscle cells caused both global and monotonic [Na+]i elevations and localized [Na+]i transients (LNats) at the cell periphery. Inhibition of nonselective cation channels with SKF-96365 (50 micromol/L) and 2-amino-4-phosphonobutyrate (75 micromol/L) reduced both global and localized [Na+]i elevations in response to ATP (1 mmol/L). This effect was mimicked by expression of a dominant negative construct of transient receptor potential channel 6. Selective inhibition of NCX-mediated Ca2+ entry with KB-R7943 (10 micromol/L) enhanced the LNats, whereas the global cytosolic [Na+] signal was unaffected. Inhibition of mitochondrial Na+ uptake with CGP-37157 (10 micromol/L) increased both LNats and global cytosolic [Na+] elevations. These findings directly demonstrate NCX regulation by LNats, which are restricted to subsarcolemmal, cytoplasmic microdomains. Analysis of the LNats, which facilitate Ca2+ entry via NCX, suggests that mitochondria limit the cytosolic diffusion of LNats generated by agonist-mediated activation of transient receptor potential channel 6-containing channels.


Assuntos
Hipertensão/fisiopatologia , Músculo Liso Vascular/fisiologia , Trocador de Sódio e Cálcio/metabolismo , Sódio/metabolismo , Canais de Cátion TRPC/metabolismo , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Animais , Aorta/citologia , Cálcio/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , Citosol/metabolismo , Humanos , Hipertensão/metabolismo , Mitocôndrias/metabolismo , Músculo Liso Vascular/citologia , Ratos , Retículo Sarcoplasmático/metabolismo , Canais de Cátion TRPC/genética , Canal de Cátion TRPC6 , Transfecção
13.
Biochem Biophys Res Commun ; 352(1): 130-4, 2007 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-17112478

RESUMO

Reversal of the Na+/Ca2+ -exchanger (NCX) has been shown to mediate Ca2+ influx during activation of G-protein linked receptors. Functional coupling between the reverse-mode NCX and the canonical transient receptor potential channels (TRPCs) has been proposed to mediate Ca2+ influx in HEK-293 cells overexpressing TRPC3. In this communication we present evidence for similar functional coupling of NCX to endogenously expressed TRPC6 in rat aorta smooth muscle cells. Selective inhibition of reverse-mode NCX with KB-R7943 and of non-selective cation-channels with SKF-96365 abolished Ca2+ influx in response to agonist stimulation (ATP). Expression of a dominant negative TRPC6 mutant also reduced the Ca2+ influx in proportion to its transfection efficiency. Calyculin A, which is known to disrupt the junctions of the plasma membrane and sarco/endoplasmic reticulum, increased global Na+ elevations and reduced stimulated Ca2+ influx. Together our data provide evidence that localized Na+ elevations are generated by TRPC6 and drive reversal of NCX to mediate Ca2+ influx.


Assuntos
Trifosfato de Adenosina/farmacologia , Cálcio/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Trocador de Sódio e Cálcio/metabolismo , Sódio/metabolismo , Canais de Cátion TRPC/metabolismo , Animais , Células Cultivadas , Toxinas Marinhas , Oxazóis/farmacologia , Ratos , Canais de Cátion TRPC/genética
14.
J Nucl Med Technol ; 34(2): 67-73; quiz 74-6, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16751582

RESUMO

Nuclear medicine technology has traditionally focused on diagnostic imaging, with therapeutics left mostly to other medical disciplines. However, after many years in development, radioimmunotherapy (RIT) has finally become a clinical reality in many nuclear medicine departments. The nuclear medicine technologist is a key player in the successful implementation of RIT. Delivery of a therapeutic regimen of tositumomab and (131)I-tositumomab provides a model for the technologist's roles and responsibilities in the developing field of RIT. This article examines the clinical rationale, logistic requirements, and imaging and dosimetry procedures required by this treatment regimen. Upon completion of this article, the reader should be able to describe the target patient population and identify the roles and responsibilities of various members of the treatment team. The reader will also gain an understanding of the treatment process, including drug administration, imaging, and therapeutic dose calculations.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Linfoma não Hodgkin/terapia , Medicina Nuclear , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/farmacocinética , Esquema de Medicação , Humanos , Radiometria , Inquéritos e Questionários , Imagem Corporal Total
16.
Exp Biol Med (Maywood) ; 229(5): 378-82, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15096649

RESUMO

Radiobiologists have been struggling to estimate the health risks from low doses of radiation in humans for decades. Health risks involve not only neoplastic diseases but also somatic mutations that may contribute to other illnesses (including birth defects and ocular maladies) and heritable mutations that may increase the risk of diseases in future generations. Low dose radiation-induced cancer in humans depends on several variables, and most of these variables are not possible to correct for in any epidemiologic study. Some of the confounding factors include (i) interaction of radiation with other physical (UV light), chemical, and biological mutagens and carcinogens in a synergistic manner; (ii) variation in repair mechanisms that depend on dose; (iii) variation in sensitivity of bystander cells to subsequent radiation exposure that depends on whether they have been pre- or postirradiated; and (iv) variation in adaptive response that depends on radiation doses and protective substances (antioxidants). In our opinion, both the linear no-threshold-response and the threshold-response models might not be suitable in predicting cancer risk at low radiation doses in a quantitative sense. Low doses of ionizing radiation should not be considered insignificant for risks of somatic and heritable mutations and neoplastic and nonneoplastic diseases in humans.


Assuntos
Radiação Ionizante , Criança , Cocarcinogênese , Relação Dose-Resposta à Radiação , Feminino , Humanos , Exposição Materna/efeitos adversos , Neoplasias Induzidas por Radiação , Gravidez , Tolerância a Radiação , Fatores de Risco
18.
J Am Coll Nutr ; 22(2): 108-17, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12672706

RESUMO

In 1982, it was established that alpha-tocopheryl succinate (alpha-TS) was the most effective form of vitamin E in comparison to alpha-tocopherol, alpha-tocopheryl acetate and alpha-tocopheryl nicotinate in inducing differentiation, inhibition of proliferation and apoptosis in cancer cells, depending upon its concentration. During the last two decades, several studies have confirmed this observation in rodent and human cancer cells in culture and in vivo (animal model). The most exciting aspect of this alpha-TS effect is that it does not affect the proliferation of most normal cells. In spite of several studies published on the anti-cancer properties of alpha-TS, the value of this form of vitamin E has not drawn significant attention from researchers and clinicians. Therefore, a critical review on the potential role of alpha-TS in the management of cancer is needed. In addition, such a review can also provide in-depth analysis of existing literature on this subject. alpha-TS treatment causes extensive alterations in gene expression; however, only some can be attributed to differentiation, inhibition of proliferation and apoptosis. alpha-TS also enhances the growth-inhibitory effect of ionizing radiation, hyperthermia, some chemotherapeutic agents and biological response modifiers on tumor cells, while protecting normal cells against some of their adverse effects. Thus, alpha-TS alone or in combination with dietary micronutrients can be useful as an adjunct to standard cancer therapy by increasing tumor response and possibly decreasing some of the toxicities to normal cells.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Vitamina E/análogos & derivados , Vitamina E/uso terapêutico , Animais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Quimioterapia Adjuvante , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Tocoferóis , Resultado do Tratamento , Células Tumorais Cultivadas , Vitamina E/efeitos adversos , Vitamina E/farmacologia
19.
J Cardiovasc Electrophysiol ; 14(1): 94-103, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12625619

RESUMO

ATP-sensitive potassium channels (K(ATP)) of vascular smooth muscle cells represent potential therapeutic targets for control of abnormal vascular contractility. The biophysical properties, regulation and pharmacology of these channels have received intense scrutiny during the past twenty years, however, the molecular basis of vascular K(ATP) channels remains ill-defined. This review summarizes the recent advancements made in our understanding of the molecular composition of vascular K(ATP) channels with a focus on the evidence that hetero-octameric complexes of Kir6.1 and SUR2B subunits constitute the vascular K(ATP) subtype responsible for control of arterial diameter by vasoactive agonists.


Assuntos
Adenosina Trifosfatases/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Canais de Potássio/metabolismo , Potenciais de Ação/fisiologia , Biotransformação/fisiologia , Humanos
20.
J Am Coll Nutr ; 21(6): 506-22, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12480796

RESUMO

The etiology of Alzheimer's disease (AD) is not well understood. Etiologic factors, chronic inflammatory reactions, oxidative and nitrosylative stresses and high cholesterol levels are thought to be important for initiating and promoting neurodegenerative changes commonly found in AD brains. Even in familial AD, oxidative stress plays an important role in the early onset of the disease. Mitochondrial damage and proteasome inhibition represent early events in the pathogenesis of AD, whereas increased processing of amyloid precursor protein (APP) to beta-amyloid (Abeta) fragments (Abeta(40) and Abeta(42)) and formation of senile plaques and neurofibrillary tangles (NFTs) represent late events. We propose a hypothesis that in idiopathic AD, epigenetic components of neurons such as mitochondria, proteasomes and post-translation protein modifications (processing of amyloid precursor protein to beta-amyloid and hyperphosphorylation of tau), rather than nuclear genes, are the primary targets for the action of diverse groups of neurotoxins. Based on epidemiologic, laboratory and limited clinical studies, we propose that a combination of non steroidal anti-inflammatory drugs (NSAIDs) and appropriate levels and types of multiple micronutrients, including antioxidants, may be more effective than the individual agents in the prevention, and they, in combination with a cholinergic agent, may be more effective in the treatment of AD than the individual agents alone. In addition, agents, which can prevent formation of plaques or dissolve these plaques may further enhance the efficacy of our proposed treatment strategy.


Assuntos
Doença de Alzheimer , Anti-Inflamatórios não Esteroides/uso terapêutico , Antioxidantes/uso terapêutico , Colinérgicos/uso terapêutico , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/etiologia , Doença de Alzheimer/prevenção & controle , Encéfalo/metabolismo , Encéfalo/patologia , Quimioterapia Combinada , Humanos , Estresse Oxidativo , Fatores de Risco , Resultado do Tratamento
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