Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 681
Filtrar
2.
Cell Rep ; 43(6): 114307, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38848216

RESUMO

The development of vaccines and therapeutics that are broadly effective against known and emergent coronaviruses is an urgent priority. We screened the circulating B cell repertoires of COVID-19 survivors and vaccinees to isolate over 9,000 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific monoclonal antibodies (mAbs), providing an expansive view of the SARS-CoV-2-specific Ab repertoire. Among the recovered antibodies was TXG-0078, an N-terminal domain (NTD)-specific neutralizing mAb that recognizes diverse alpha- and beta-coronaviruses. TXG-0078 achieves its exceptional binding breadth while utilizing the same VH1-24 variable gene signature and heavy-chain-dominant binding pattern seen in other NTD-supersite-specific neutralizing Abs with much narrower specificity. We also report CC24.2, a pan-sarbecovirus neutralizing antibody that targets a unique receptor-binding domain (RBD) epitope and shows similar neutralization potency against all tested SARS-CoV-2 variants, including BQ.1.1 and XBB.1.5. A cocktail of TXG-0078 and CC24.2 shows protection in vivo, suggesting their potential use in variant-resistant therapeutic Ab cocktails and as templates for pan-coronavirus vaccine design.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , Epitopos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Humanos , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/virologia , Epitopos/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Monoclonais/imunologia , Animais , Betacoronavirus/imunologia , Camundongos
3.
JBMR Plus ; 8(1): ziad004, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38690127

RESUMO

Craniofacial and dentoalveolar abnormalities are present in all types of osteogenesis imperfecta (OI). Mouse models of the disorder are critical to understand these abnormalities and underlying OI pathogenesis. Previous studies on severely affected OI mice report a broad spectrum of craniofacial phenotypes, exhibiting some similarities to the human disorder. The Brtl/+ and G610c/+ are moderately severe and mild-type IV OI, respectively. Little is known about the aging effects on the craniofacial bones of these models and their homology to human OI. This study aimed to analyze the Brtl/+ and G610c/+ craniofacial morphometries during aging to establish suitability for further OI craniofacial bone intervention studies. We performed morphological measurements on the micro-CT-scanned heads of 3-wk-old, 3-mo-old, and 6-mo-old female Brtl/+ and G610c/+ mice. We observed that Brtl/+ skulls are shorter in length than WT (P < .05), whereas G610c/+ skulls are similar in length to their WT counterparts. The Brtl/+ mice exhibit alveolar bone with a porotic-like appearance that is not observed in G610c/+. As they age, Brtl/+ mice show severe bone resorption in both the maxilla and mandible (P < .05). By contrast, G610c/+ mice experience mandibular resorption consistently across all ages, but maxillary resorption is only evident at 6 mo (P < .05). Western blot shows high osteoclastic activities in the Brtl/+ maxilla. Both models exhibit delayed pre-functional eruptions of the third molars (P < .05), which are similar to those observed in some bisphosphonate-treated OI subjects. Our study shows that the Brtl/+ and G610c/+ mice display clear features found in type IV OI patients; both show age-related changes in the craniofacial growth phenotype. Therefore, understanding the craniofacial features of these models and how they age will allow us to select the most accurate mouse model, mouse age, and bone structure for the specific craniofacial bone treatment of differing OI groups.

4.
JTCVS Open ; 17: 152-161, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38420544

RESUMO

Objectives: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) with concomitant percutaneous microaxial left ventricular assist device support is an emerging treatment modality for cardiogenic shock (CS). Survival outcomes by CS etiology with this support strategy have not been well described. Methods: This study was a retrospective, single-center analysis of patients with CS due to acute myocardial infarction (AMI-CS) or decompensated heart failure (ADHF-CS) supported with VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support from December 2020 to January 2023. Results: A total of 44 patients were included (AMI-CS, n = 20, and ADHF-CS, n = 24). Patients with AMI-CS and ADHF-CS had similar survival at 90 days postdischarge (P = .267) with similar destinations after support (P = .220). Patients with AMI-CS initially supported with VA-ECMO were less likely to survive 90 days postdischarge (P = .038) when compared with other cohorts. Limb ischemia and acute kidney injury occurred more frequently in patients presenting with AMI-CS (P =.013; P = .030). Subanalysis of ADHF-CS patients into acute-on-chronic decompensated HF and de novo HF demonstrated no difference in survival or destination. Conclusions: VA-ECMO with concomitant percutaneous microaxial left ventricular assist device support can be used to successfully manage patients with CS. There is no difference in survival or destination for AMI-CS and ADHF-CS with this support strategy. AMI-CS patients with initial VA-ECMO support have increased mortality in comparison to other cohorts. Future multicenter studies are required to fully analyze the differences between AMI-CS and ADHF-CS with this support strategy.

5.
Sci Signal ; 17(821): eadg2622, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38289985

RESUMO

Targeted degradation regulates the activity of the transcriptional repressor Bcl6 and its ability to suppress oxidative stress and inflammation. Here, we report that abundance of endothelial Bcl6 is determined by its interaction with Golgi-localized pannexin 3 (Panx3) and that Bcl6 transcriptional activity protects against vascular oxidative stress. Consistent with data from obese, hypertensive humans, mice with an endothelial cell-specific deficiency in Panx3 had spontaneous systemic hypertension without obvious changes in channel function, as assessed by Ca2+ handling, ATP amounts, or Golgi luminal pH. Panx3 bound to Bcl6, and its absence reduced Bcl6 protein abundance, suggesting that the interaction with Panx3 stabilized Bcl6 by preventing its degradation. Panx3 deficiency was associated with increased expression of the gene encoding the H2O2-producing enzyme Nox4, which is normally repressed by Bcl6, resulting in H2O2-induced oxidative damage in the vasculature. Catalase rescued impaired vasodilation in mice lacking endothelial Panx3. Administration of a newly developed peptide to inhibit the Panx3-Bcl6 interaction recapitulated the increase in Nox4 expression and in blood pressure seen in mice with endothelial Panx3 deficiency. Panx3-Bcl6-Nox4 dysregulation occurred in obesity-related hypertension, but not when hypertension was induced in the absence of obesity. Our findings provide insight into a channel-independent role of Panx3 wherein its interaction with Bcl6 determines vascular oxidative state, particularly under the adverse conditions of obesity.


Assuntos
Hipertensão , Fatores de Transcrição , Animais , Humanos , Camundongos , Diferenciação Celular , Proliferação de Células/fisiologia , Conexinas/metabolismo , Peróxido de Hidrogênio/farmacologia , Obesidade , Estresse Oxidativo , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Fatores de Transcrição/metabolismo
6.
Res Sq ; 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38260264

RESUMO

Abstract Purpose: The finding of reduced numbers of class-switched memory B cells (CSM) in peripheral blood is widely used to assist the diagnosis and subclassification of CVID. Limited data exists on this finding in relation to the entire class of PADs. In this study, consecutive 8-marker comprehensive B-cell panel results were analyzed to determine how reduced CSM quantities might inform the pathophysiology of CVID and other humoral immunodeficiencies. Methods: Subpopulations of CD27+ memory B cells from 64 consecutive subjects with or without humoral immunodeficiency were examined to identify associations with diagnosis and serum immunoglobulin level. Results: CD27+IgM-IgD- percentage (CSM%) was correlated with IgG level in a discontinuous manner with an estimated change point of 9.7% (95% CI: 4.7, 12.4). All subjects with a CSM% below 9.7% had substantially lower serum IgG and IgA levels compared with those above 9.7. CSM% below 9.7% is not associated with serum IgM level. Rather, the proportion of CD27+IgMonly B cells (IgMonly or IgMonly%) is correlated with serum IgM. Conclusion: Low CSM% may mark an endotype of humoral immune dysfunction defined by either loss of class switching or critical failure of the coordinated production of both memory cells and long-lived plasma cells responsible for adequate immunoglobulin levels in humans. In patients with low CSM%, maintenance or expansion of IgMonly cells and IgM production suggests the former explanation, while concomitant loss of IgMonly cells suggests the latter. These findings provide a simple endotypic stratification method for future studies on the failed coordinated B cell response in humans with PAD.

7.
medRxiv ; 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37546750

RESUMO

Background: VA-ECMO with concomitant Impella support (ECpella) is an emerging treatment modality for cardiogenic shock (CS). Survival outcomes by CS etiology with ECpella support have not been well-described. Methods: This study was a retrospective, single-center analysis of patients with cardiogenic shock due to acute myocardial infarction (AMI-CS) or decompensated heart failure (ADHF-CS) supported with ECpella from December 2020 to January 2023. Primary outcomes included 90-day survival post-discharge and destination after support. Secondary outcomes included complications post-ECpella support. Results: A total of 44 patients were included (AMI-CS, n = 20, and ADHF-CS, n = 24). Patients with AMI-CS and ADHF-CS had similar survival 90 days post-discharge (p = .267) with similar destinations after ECpella support (p = .220). Limb ischemia and acute kidney injury occurred more frequently in patients presenting with AMI-CS (p=.013; p = .030). Patients with initial Impella support were more likely to survive ECpella support and be bridged to transplant (p=.033) and less likely to have a cerebrovascular accident (p=.016). Sub-analysis of ADHF-CS patients into acute-on-chronic decompensated heart failure and de novo heart failure demonstrated no difference in survival or destination. Conclusion: ECpella can be used to successfully manage patients with CS. There is no difference in survival or destination for AMI-CS and ADHF-CS in patients with ECpella support. Patients with initial Impella support are more likely to survive ECpella support and bridge to transplant. Future multicenter studies are required to fully analyze the differences between AMI-CS and ADHF-CS with ECpella support.

8.
J Outdoor Recreat Tour ; 41: 100482, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37521256

RESUMO

The emergence of Coronavirus 19 led to societal and behavioral changes, including intensified use of many public parks and trails for mental respite and leisure time physical activity. As visitors sought stress-relief in the great outdoors, they also encountered stressful situations as they navigated risk exposure. Recommendations to physically distance between parties was a key component to reduce risk, but compliance is unknown in the outdoor arena. This observational study of more than 10 000 trail user encounters documented distancing and enabled predictive analysis that revealed wider trails, smaller groups and signage led to greater distancing compliance. Managers and planners can integrate these findings immediately and in consideration of future trail designs to minimize risk exposure. Management implications: Select site features increase odds of distancing compliance and can inform management decisions and designs immediately and in addressing future use surges: wider trails, unpaved surfaces, and COVID-19 signage.As distancing compliance waned with time but signage increased compliance, innovative and dynamic signs may sustain compliance and multi-media communications should be considered.Both activity size and group type influence distancing so considering group size recommendations and activity separation are in order.

9.
Biol Reprod ; 109(2): 125-136, 2023 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-37265359

RESUMO

The fallopian tubes (FTs) are part of the female upper genital tract. The healthy FT provides the biological environment for successful fertilization and facilitates the subsequent movement of the conceptus to the endometrial cavity. However, when the FT is damaged, as with salpingitis, pyosalpinx, and hydrosalpinx, it may increase the risk of an ectopic pregnancy, a life-threatening condition. Decidualization refers to a multifactorial process by which the endometrium changes to permit blastocyst implantation. The decidualization reaction is vital for endometrial receptivity during the window of implantation. To date, no comprehensive review that collates evidence on decidualization in the human FT has been conducted. Therefore, the aim of this review is to compile the current evidence on cellular decidualization occurring in the healthy and pathological FT in women of reproductive age. A literature search was conducted using five databases and identified 746 articles, 24 of which were analyzed based on inclusion and exclusion criteria. The available evidence indicates that the FT are able to undergo decidual changes under specific circumstances; however, the exact mechanism by which this occurs is poorly understood. Further research is needed to elucidate the mechanism by which decidualization can occur in the FT.


Assuntos
Endométrio , Tubas Uterinas , Gravidez , Feminino , Humanos , Implantação do Embrião , Útero , Decídua , Células Estromais
10.
bioRxiv ; 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-37034676

RESUMO

Development of vaccines and therapeutics that are broadly effective against known and emergent coronaviruses is an urgent priority. Current strategies for developing pan-coronavirus countermeasures have largely focused on the receptor binding domain (RBD) and S2 regions of the coronavirus Spike protein; it has been unclear whether the N-terminal domain (NTD) is a viable target for universal vaccines and broadly neutralizing antibodies (Abs). Additionally, many RBD-targeting Abs have proven susceptible to viral escape. We screened the circulating B cell repertoires of COVID-19 survivors and vaccinees using multiplexed panels of uniquely barcoded antigens in a high-throughput single cell workflow to isolate over 9,000 SARS-CoV-2-specific monoclonal Abs (mAbs), providing an expansive view of the SARS-CoV-2-specific Ab repertoire. We observed many instances of clonal coalescence between individuals, suggesting that Ab responses frequently converge independently on similar genetic solutions. Among the recovered antibodies was TXG-0078, a public neutralizing mAb that binds the NTD supersite region of the coronavirus Spike protein and recognizes a diverse collection of alpha- and beta-coronaviruses. TXG-0078 achieves its exceptional binding breadth while utilizing the same VH1-24 variable gene signature and heavy chain-dominant binding pattern seen in other NTD supersite-specific neutralizing Abs with much narrower specificity. We also report the discovery of CC24.2, a pan-sarbecovirus neutralizing mAb that targets a novel RBD epitope and shows similar neutralization potency against all tested SARS-CoV-2 variants, including BQ.1.1 and XBB.1.5. A cocktail of TXG-0078 and CC24.2 provides protection against in vivo challenge with SARS-CoV-2, suggesting potential future use in variant-resistant therapeutic Ab cocktails and as templates for pan-coronavirus vaccine design.

11.
Curr Opin Pharmacol ; 69: 102359, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36858833

RESUMO

Pannexin channels play fundamental roles in regulating inflammation and have been implicated in many diseases including hypertension, stroke, and neuropathic pain. Thus, the ability to pharmacologically block these channels is a vital component of several therapeutic approaches. Pharmacologic interrogation of model systems also provides a means to discover new roles for pannexins in cell physiology. Here, we review the state of the art for agents that can be used to block pannexin channels, with a focus on chemical pharmaceuticals and peptide mimetics that act on pannexin 1. Guidance on interpreting results obtained with pannexin pharmacologics in experimental systems is discussed, as well as strengths and caveats of different agents, including specificity and feasibility of clinical application.


Assuntos
Conexinas , Modelos Biológicos , Humanos
12.
J Thromb Haemost ; 21(7): 1891-1902, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36958516

RESUMO

BACKGROUND: The hemostatic plug formation at sites of vascular injury is strongly dependent on rapid platelet activation and integrin-mediated adhesion and aggregation. However, to prevent thrombotic complications, platelet aggregate formation must be a self-limiting process. The second-wave mediator adenosine diphosphate (ADP) activates platelets via Gq-coupled P2Y1 and Gi-coupled P2Y12 receptors. After ADP exposure, the P2Y1 receptor undergoes rapid phosphorylation-induced desensitization, a negative feedback mechanism believed to be critical for limiting thrombus growth. OBJECTIVE: The objective of this study was to examine the role of rapid P2Y1 receptor desensitization on platelet function and thrombus formation in vivo. METHODS: We analyzed a novel knock-in mouse strain expressing a P2Y1 receptor variant that cannot be phosphorylated beyond residue 340 (P2Y1340-0P), thereby preventing the desensitization of the receptor. RESULTS: P2Y1340-0P mice followed a Mendelian inheritance pattern, and peripheral platelet counts were comparable between P2Y1340-0P/340-0P and control mice. In vitro, P2Y1340-0P/340-0P platelets were hyperreactive to ADP, showed a robust activation response to the P2Y1 receptor-selective agonist, MRS2365, and did not desensitize in response to repeated ADP challenge. We observed increased calcium mobilization, protein kinase C substrate phosphorylation, alpha granule release, activation of the small GTPase Rap1, and integrin inside-out activation/aggregation. This hyperreactivity, however, did not lead to increased platelet adhesion or excessive plug formation under physiological shear conditions. CONCLUSION: Our studies demonstrate that receptor phosphorylation at the C-terminus is critical for P2Y1 receptor desensitization in platelets and that impaired desensitization leads to increased P2Y1 receptor signaling in vitro. Surprisingly, desensitization of the P2Y1 receptor is not required for limiting platelet adhesion/aggregation at sites of vascular injury, likely because ADP is degraded quickly or washed away in the bloodstream.


Assuntos
Trombose , Lesões do Sistema Vascular , Camundongos , Animais , Agregação Plaquetária , Plaquetas/metabolismo , Hemostasia , Trombose/genética , Trombose/prevenção & controle , Trombose/metabolismo , Difosfato de Adenosina/farmacologia , Integrinas/metabolismo , Receptores Purinérgicos P2Y1/genética , Receptores Purinérgicos P2Y1/metabolismo , Receptores Purinérgicos P2Y12/genética , Receptores Purinérgicos P2Y12/metabolismo
13.
Radiography (Lond) ; 29(2): 347-354, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36736147

RESUMO

INTRODUCTION: Magnetic Resonance (MR)-only radiotherapy for prostate cancer has previously been reported using fiducial markers for on-treatment verification. MR-Cone Beam Computed Tomography (CBCT) soft-tissue matching does not require invasive fiducial markers and enables MR-only treatments to other pelvic cancers. This study evaluated the first clinical implementation of MR-only prostate radiotherapy using MR-CBCT soft-tissue matching. METHODS: Twenty prostate patients were treated with MR-only radiotherapy using a synthetic (s)CT-optimised plan with MR-CBCT soft-tissue matching. Two MR sequences were acquired: small Field Of View (FOV) for target delineation and large FOV for organs at risk delineation, sCT generation and on-treatment verification. Patients also received a CT for validation. The prostate was independently contoured on the small FOV MR, copied to the registered CT and modified if there were MR-CT soft-tissue alignment differences (MR-CT volume). This was compared to the MR-only volume with a paired t-test. The treatment plan was recalculated on CT and the doses compared. Independent offline CT-CBCT matches for 5/20 fractions were performed by three therapeutic radiographers using the MR-only contours and compared to the online MR-CBCT matches using two one-sided paired t-tests for equivalence within ±1 mm. RESULTS: The MR-only volumes were significantly smaller than MR-CT (p = 0.003), with a volume ratio 0.92 ± 0.02 (mean ± standard error). The sCT isocentre dose difference to CT was 0.2 ± 0.1%. MR-CBCT soft-tissue matching was equivalent to CT-CBCT (p < 0.001), with differences of 0.1 ± 0.2 mm (vertical), -0.1 ± 0.2 mm (longitudinal) and 0.0 ± 0.1 mm (lateral). CONCLUSIONS: MR-only radiotherapy with soft-tissue matching has been successfully clinically implemented. It produced significantly smaller target volumes with high dosimetric and on-treatment matching accuracy. IMPLICATIONS FOR PRACTICE: MR-only prostate radiotherapy can be safely delivered without using invasive fiducial markers. This enables MR-only radiotherapy to be extended to other pelvic cancers where fiducial markers cannot be used.


Assuntos
Neoplasias Pélvicas , Tomografia Computadorizada de Feixe Cônico Espiral , Masculino , Humanos , Próstata/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Espectroscopia de Ressonância Magnética
14.
Am J Dermatopathol ; 45(3): 192-195, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36728283

RESUMO

ABSTRACT: Adenodermatofibromas are an extremely rare subtype of dermatofibroma (DF) characterized by a dermal proliferation of spindle-shaped fibroblasts and histocytes, dilated glandular structures with apocrine secretion, and prominent vascular proliferation, with or without hemosiderotic features. We describe a recent extraordinary case of a hemosiderotic adenodermatofibroma in a 25-year-old female. We review histologic findings and theories behind etiology, as well as review the spectrum of clinical presentations for this lesion. We also discuss imaging findings that may make identification of these entities challenging.


Assuntos
Hemossiderose , Histiocitoma Fibroso Benigno , Neoplasias Cutâneas , Feminino , Humanos , Adulto , Neoplasias Cutâneas/patologia , Histiocitoma Fibroso Benigno/patologia , Hemossiderose/patologia , Fibroblastos/patologia , Histiócitos/patologia
15.
Cancer Prev Res (Phila) ; 16(4): 239-245, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36630997

RESUMO

Although lung cancer screening (LCS) with annual low-dose chest CT has been shown to reduce lung cancer deaths, it remains underutilized. Northern Plains American Indian and Alaska Native (AI/AN) communities experience extreme lung cancer disparities, and little is known about the acceptance and adoption of LCS in these groups. We conducted interviews with healthcare professionals and focus groups with patients in an urban Minnesota community clinic serving AI/AN. Data collection took place during winter 2019-2020. Indigenous researchers collected and analyzed the data for emergent themes using simultaneous collaborative consensus with a LCS researcher. Participants reported some similar barriers to LCS as previous studies reported but also shared some new insights into traditional ways of knowing and recommendations for effectively implementing this evidence-based preventive care service. Lung screening is largely acceptable to patients and healthcare personnel in an AI/AN-serving community clinic. We identified barriers as previously reported in other populations but also identified some unique barriers and motivators. For example, the concept of the seven generations may provide motivation to maintain one's health for future generations while providing additional support during screening for persons traumatized by the Western medicine health system may facilitate increased screening uptake. PREVENTION RELEVANCE: Secondary prevention of lung cancer through screening is potentially lifesaving considering that overall survival of lung cancer is 20% at 5 years but curable if detected at an early stage. This work provides insight into culturally tailored approaches to implementing the service in individuals at high risk of the disease.


Assuntos
Indígenas Norte-Americanos , Neoplasias Pulmonares , Humanos , Minnesota , Detecção Precoce de Câncer , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/prevenção & controle
16.
Nano Lett ; 23(3): 931-938, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36700844

RESUMO

The need for novel materials for energy storage and generation calls for chemical control at the atomic scale in nanomaterials. Ordered double-transition-metal MXenes expanded the chemical diversity of the family of atomically layered 2D materials since their discovery in 2015. However, atomistic tunability of ordered MXenes to achieve ideal composition-property relationships has not been yet possible. In this study, we demonstrate the synthesis of Mo2+αNb2-αAlC3 MAX phases (0 ≤ α ≤ 0.3) and confirm the preferential ordering behavior of Mo and Nb in the outer and inner M layers, respectively, using density functional theory, Rietveld refinement, and electron microscopy methods. We also synthesize their 2D derivative Mo2+αNb2-αC3Tx MXenes and exemplify the effect of preferential ordering on their hydrogen evolution reaction electrocatalytic behavior. This study seeks to inspire further exploration of the ordered double-transition-metal MXene family and contribute composition-behavior tools toward application-driven design of 2D materials.

17.
Thromb Haemost ; 123(5): 501-509, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36716775

RESUMO

Cancer patients have increased thrombosis and bleeding compared with the general population. Cancer is associated with activation of both platelets and coagulation. Mouse models have been used to study the dysregulation of platelets and coagulation in cancer. We established a mouse model of pancreatic cancer in which tissue factor-expressing human pancreatic tumors (BxPC-3) are grown in nude mice. Tumor-bearing mice have an activated coagulation system and increased venous thrombosis compared to control mice. We also showed that tumor-derived, tissue factor-positive extracellular vesicles activated platelets ex vivo and in vivo. In this study, we determined the effect of tumors on a platelet-dependent arterial thrombosis model. Unexpectedly, we observed significantly reduced carotid artery thrombosis in tumor-bearing mice compared to controls. In addition, we observed significantly increased tail bleeding in tumor-bearing mice compared to controls. These results suggested that the presence of the tumor affected platelets. Indeed, tumor-bearing mice exhibited a significant decrease in platelet count and an increase in mean platelet volume and percentage of reticulated platelets, findings that are consistent with increased platelet turnover. Levels of the platelet activation marker platelet factor 4 were also increased in tumor-bearing mice. We also observed decreased platelet receptor expression in tumor-bearing mice and reduced levels of active αIIb/ß3 integrin in response to PAR4 agonist peptide and convulxin in platelets from tumor-bearing mice compared with platelets from control mice. In summary, our study suggests that in tumor-bearing mice there is chronic platelet activation, leading to thrombocytopenia, decreased receptor expression, and impaired platelet adhesive function.


Assuntos
Neoplasias Pancreáticas , Trombose , Humanos , Camundongos , Animais , Tromboplastina/metabolismo , Camundongos Nus , Plaquetas/metabolismo , Ativação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Neoplasias Pancreáticas/complicações , Hemorragia/complicações , Agregação Plaquetária
18.
Artif Organs ; 47(2): 361-369, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36271639

RESUMO

BACKGROUND: Impella 5.5 (Abiomed; Danvers, MA) (IMP5) is a commonly used, surgically implanted, tMCS device that requires systemic anticoagulation and purge solution to avoid pump failure. To avoid heparin-induced thrombocytopenia (HIT) from unfractionated heparin (UFH) use, our program has explored the utility of bivalirudin (BIV) for systemic anticoagulation and sodium bicarbonate-dextrose purge solution (SBPS) in IMP5.5. METHODS: This single center, retrospective study included 34 patients supported on IMP5.5 with BIV based AC and SBPS between December 1st 2020 to December 1st 2021.The efficacy and safety end points were incidence of development of HIT, Tissue Plasminogen Activator (tPA) use for suspected pump thrombosis, stroke, and device failure as well as clinically significant bleeding. RESULTS: The median duration of IMP5.5 support was 9.8 days (IQR: 6-15). Most patients were bridged to HTX (58%) followed by recovery (27%) and LVAD implantation (15%). Patients were therapeutic on bivalirudin for 64% of their IMP5.5 support. One patient (2.9%) suffered from ischemic stroke and 26.5% (9) patients developed clinically significant bleeding. tPA was administered to 7(21%) patients. One patient in the entire cohort developed HIT. CONCLUSIONS: Our experience supports the use of systemic BIV and SBPS as a method to avoid heparin exposure in a patient population predisposed to the development of HIT.


Assuntos
Heparina , Trombocitopenia , Humanos , Heparina/efeitos adversos , Anticoagulantes/efeitos adversos , Ativador de Plasminogênio Tecidual/efeitos adversos , Bicarbonato de Sódio , Estudos Retrospectivos , Hirudinas/efeitos adversos , Fragmentos de Peptídeos/efeitos adversos , Hemorragia/induzido quimicamente , Proteínas Recombinantes/efeitos adversos , Resultado do Tratamento
19.
J Am Coll Cardiol ; 80(17): 1633-1644, 2022 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-36265959

RESUMO

BACKGROUND: Lower CD4+ cell count in people with HIV infection (PWH) is associated with increased cardiovascular disease (CVD) risk. Whether subsets of CD4+ T helper cells are linked with CVD is unclear. OBJECTIVES: The aim of this study was to explore the association between peripherally circulating CD4+ T cell subsets and incident CVD. METHODS: Data from 1,860 participants (1,270 PWH) without prevalent CVD from the VACS (Veterans Aging Cohort Study), a prospective, observational cohort of veterans with and without HIV infection, were analyzed. T cell subsets were quantified in baseline samples using flow cytometry. Incident CVD events were identified using International Classification of Diseases-9th Revision and International Classification of Diseases-10th Revision diagnosis and procedure codes. Participants were followed from baseline date (2005-2006) to the first of CVD incidence, death, or September 30, 2016. Cox proportional hazards regression was used to model associations between these T cell subsets and the risk for incident CVD while adjusting for demographics and other CVD risk factors. RESULTS: The median participant age at baseline was 51.6 years. Most were male (94%) and of Black race (69.1%). There were 344 incident CVD events (219 in PWH) during follow-up (median 9.8 years). In PWH, higher proportions (per SD increment) of T helper type 17 cells (adjusted HR: 1.19; 95% CI: 1.08-1.31), T effector memory cells re-expressing CD45RA (adjusted HR: 1.19; 95% CI: 1.07-1.34), and CD28null cells (adjusted HR: 1.18; 95% CI: 1.03-1.34) were significantly associated with an increased risk for incident CVD. Among those without HIV infection, no T cell subsets were significantly associated with CVD. CONCLUSIONS: Among PWH, T helper type 17 cells, senescent cells, and CD4+ T effector memory cells re-expressing CD45RA were significantly associated with incident CVD that was not explained by CVD risk factors.


Assuntos
Doenças Cardiovasculares , Infecções por HIV , Humanos , Masculino , Pessoa de Meia-Idade , Feminino , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Infecções por HIV/diagnóstico , Doenças Cardiovasculares/diagnóstico , Estudos de Coortes , Fatores de Risco , Estudos Prospectivos , Antígenos CD28 , Linfócitos T , Fatores de Risco de Doenças Cardíacas , Incidência
20.
Nature ; 611(7935): 352-357, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36289331

RESUMO

The vertebrate adaptive immune system modifies the genome of individual B cells to encode antibodies that bind particular antigens1. In most mammals, antibodies are composed of heavy and light chains that are generated sequentially by recombination of V, D (for heavy chains), J and C gene segments. Each chain contains three complementarity-determining regions (CDR1-CDR3), which contribute to antigen specificity. Certain heavy and light chains are preferred for particular antigens2-22. Here we consider pairs of B cells that share the same heavy chain V gene and CDRH3 amino acid sequence and were isolated from different donors, also known as public clonotypes23,24. We show that for naive antibodies (those not yet adapted to antigens), the probability that they use the same light chain V gene is around 10%, whereas for memory (functional) antibodies, it is around 80%, even if only one cell per clonotype is used. This property of functional antibodies is a phenomenon that we call light chain coherence. We also observe this phenomenon when similar heavy chains recur within a donor. Thus, although naive antibodies seem to recur by chance, the recurrence of functional antibodies reveals surprising constraint and determinism in the processes of V(D)J recombination and immune selection. For most functional antibodies, the heavy chain determines the light chain.


Assuntos
Anticorpos , Seleção Clonal Mediada por Antígeno , Cadeias Pesadas de Imunoglobulinas , Cadeias Leves de Imunoglobulina , Animais , Sequência de Aminoácidos , Anticorpos/química , Anticorpos/genética , Anticorpos/imunologia , Antígenos/química , Antígenos/imunologia , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/imunologia , Cadeias Pesadas de Imunoglobulinas/química , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/imunologia , Mamíferos , Cadeias Leves de Imunoglobulina/química , Cadeias Leves de Imunoglobulina/genética , Cadeias Leves de Imunoglobulina/imunologia , Memória Imunológica , Recombinação V(D)J , Seleção Clonal Mediada por Antígeno/genética , Seleção Clonal Mediada por Antígeno/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...