Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 191
Filtrar
1.
Indian J Hematol Blood Transfus ; 40(3): 448-453, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39011268

RESUMEN

The platelet count in a healthy individual varies between 150 and 450 × 109/L. This study explores the factors affecting this variation in platelet count in healthy blood donors selected for platelet donation. This retrospective study comprises an analysis of platelet donor data between the year 2016-2022. The pre-recorded donor details such as age, gender, blood group, body mass index (BMI), and complete blood counts were collected and analyzed using the software 'R' (version 4.1.0). The statistical analysis consists of a test of normalcy followed by descriptive details and advanced statistics such as correlation and regression analysis to predict the variables affecting platelet count. The p-value of less than 0.05 was taken as significant. The median (IQR) of hemoglobin, platelet count, and total leucocyte count (TLC) was 142(135-150) g/L, 239(204-285) × 109/L, and 7.6(6.4-8.8) × 109/L, respectively. The platelet count was positively correlated with TLC (p = 0.000) and negatively with the age of the platelet donor (p = 0.001). The Kruskal-Wallis test detected significant differences in the platelet count among the ABO blood group (p = 0.008). Further, regression analysis confirms the independent positive association of total platelet count with the total leucocyte count (p = 0.000) and the negative association of platelet count with age (p = 0.004). This study concludes the strong dependency of total platelet count with total leucocyte count, age, and blood group.

2.
Eur J Cancer ; 209: 114236, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39059185

RESUMEN

BACKGROUND: The multi-centre two-stage SCALOP-2 trial (ISRCTN50083238) assessed whether dose escalation of consolidative chemoradiotherapy (CRT) or concurrent sensitization using the protease inhibitor nelfinavir improve outcomes in locally advanced pancreatic cancer (LAPC) following four cycles of gemcitabine/nab-paclitaxel. METHODS: In stage 1, the maximum tolerated dose (MTD) of nelfinavir concurrent with standard-dose CRT (50.4 Gy in 28 fractions) was identified from a cohort of 27 patients. In stage 2, 159 patients were enrolled in an open-label randomized controlled comparison of standard versus high dose (60 Gy in 30 fractions) CRT, with or without nelfinavir at MTD. Primary outcomes following dose escalation and nelfinavir use were respectively overall survival (OS) and progression free survival (PFS). Secondary endpoints included health-related quality of life (HRQoL). RESULTS: High dose CRT did not improve OS (16.9 (60 % confidence interval, CI 16.2-17.7) vs. 15.6 (60 %CI 14.3-18.2) months; adjusted hazard ratio, HR 1.13 (60 %CI 0.91-1.40; p = 0.68)). Similarly, median PFS was not improved by nelfinavir (10.0 (60 %CI 9.9-10.2) vs. 11.1 (60 %CI 10.3-12.8) months; adjusted HR 1.71 (60 %CI 1.38-2.12; p = 0.98)). Local progression at 12 months was numerically lower with high-dose CRT than with standard dose CRT (n = 11/46 (23.9 %) vs. n = 15/45 (33.3 %)). Neither nelfinavir nor radiotherapy dose escalation impacted on treatment compliance or grade 3/4 adverse event rate. There were no sustained differences in HRQoL scores between treatment groups over 28 weeks post-treatment. CONCLUSIONS: Dose-escalated CRT may improve local tumour control and is well tolerated when used as consolidative treatment in LAPC but does not impact OS. Nelfinavir use does not improve PFS.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica , Quimioradioterapia , Nelfinavir , Neoplasias Pancreáticas , Humanos , Nelfinavir/uso terapéutico , Nelfinavir/administración & dosificación , Nelfinavir/efectos adversos , Neoplasias Pancreáticas/terapia , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/mortalidad , Masculino , Femenino , Persona de Mediana Edad , Anciano , Quimioradioterapia/efectos adversos , Quimioradioterapia/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Adulto , Paclitaxel/administración & dosificación , Paclitaxel/efectos adversos , Dosis Máxima Tolerada , Desoxicitidina/análogos & derivados , Desoxicitidina/administración & dosificación , Desoxicitidina/efectos adversos , Desoxicitidina/uso terapéutico , Gemcitabina , Anciano de 80 o más Años , Calidad de Vida , Albúminas/administración & dosificación , Albúminas/uso terapéutico , Albúminas/efectos adversos , Supervivencia sin Progresión , Inhibidores de Proteasas/efectos adversos , Inhibidores de Proteasas/uso terapéutico , Inhibidores de Proteasas/administración & dosificación
3.
Sci Adv ; 10(27): eadm9071, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38968363

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer, a disease with dismal overall survival. Advances in treatment are hindered by a lack of preclinical models. Here, we show how a personalized organotypic "avatar" created from resected tissue allows spatial and temporal reporting on a complete in situ tumor microenvironment and mirrors clinical responses. Our perfusion culture method extends tumor slice viability, maintaining stable tumor content, metabolism, stromal composition, and immune cell populations for 12 days. Using multiplexed immunofluorescence and spatial transcriptomics, we identify immune neighborhoods and potential for immunotherapy. We used avatars to assess the impact of a preclinically validated metabolic therapy and show recovery of stromal and immune phenotypes and tumor redifferentiation. To determine clinical relevance, we monitored avatar response to gemcitabine treatment and identify a patient avatar-predictable response from clinical follow-up. Thus, avatars provide valuable information for syngeneic testing of therapeutics and a truly personalized therapeutic assessment platform for patients.


Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Medicina de Precisión , Microambiente Tumoral , Animales , Humanos , Carcinoma Ductal Pancreático/inmunología , Carcinoma Ductal Pancreático/terapia , Carcinoma Ductal Pancreático/patología , Línea Celular Tumoral , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapéutico , Desoxicitidina/farmacología , Gemcitabina , Inmunoterapia/métodos , Neoplasias Pancreáticas/inmunología , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/terapia , Medicina de Precisión/métodos , Microambiente Tumoral/inmunología
4.
Fungal Biol ; 128(4): 1876-1884, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38876540

RESUMEN

The endophytic fungus Chaetomium nigricolor culture filtrate's hexane extract was used to identify a cytotoxic very long-chain fatty acid. Based on multiple spectroscopic investigations, the structure of the compound was predicted to be an unsaturated fatty acid, Nonacosenoic acid (NA). Using the MTT assay, the compound's cytotoxic potential was evaluated against MCF-7, A-431, U-251, and HEK-293 T cells. The compound was moderately cytotoxic to breast carcinoma cell line, MCF-7 cells and negligibly cytotoxic to non-cancerous cell line HEK-293 T cells. The compound exhibited mild cytotoxic activity against A-431 and U-251 cells. The compound also induced ROS generation and mitochondrial depolarization in MCF-7 cells when assessed via the NBT and JC-1 assays, respectively. This is the first report on the production of nonacosenoic acid from the endophytic fungus Chaetomium nigricolor and the assessment of its bioactivity.


Asunto(s)
Chaetomium , Endófitos , Ácidos Grasos Insaturados , Chaetomium/química , Humanos , Endófitos/química , Endófitos/metabolismo , Endófitos/aislamiento & purificación , Ácidos Grasos Insaturados/farmacología , Antineoplásicos/farmacología , Antineoplásicos/química , Línea Celular Tumoral , Tallos de la Planta/microbiología , Tallos de la Planta/química , Supervivencia Celular/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Línea Celular
5.
Radiother Oncol ; 195: 110224, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38479442

RESUMEN

BACKGROUND: The availability of circulating biomarkers that are predictive of treatment response or prognostic of overall outcome could enable the personalised and adaptive use of radiotherapy (RT) in patients with oesophageal adenocarcinoma (OAC) and squamous cell carcinoma (OSCC). METHODS: A systematic review was carried out following Preferred Reporting Items for Systematic Reviews guidance. Medline, EMBASE, PubMed, Cochrane Library, CINAHL, Scopus and the Web of Science databases were searched for studies published between January 2005-February 2023 relating to circulating biomarkers evaluated in the context of neoadjuvant or definitive RT delivered for OAC/OSCC. Study quality was assessed using predefined criteria. RESULTS: A total of 3012 studies were screened and 57 subsequently included, across which 61 biomarkers were reported. A majority (43/57,75.4%) of studies were of Asian origin and retrospective (40/57, 70.2%), with most (52/57, 91.2%) biomarkers reported in the context of patients with OSCC. There was marked inter-study heterogeneity in patient populations, treatment characteristics, biomarker measurement and the cut points used to define biomarker positivity. Nevertheless, there is evidence for the prognostic and predictive value of circulating tumour DNA and numerous miRNAs in OAC and OSCC, as well as for the prognostic and predictive value of circulating levels of CYFRA21.1 in OSCC. CONCLUSIONS: There is consistent evidence for the potential predictive and prognostic value of a small number of biomarkers in OSCC and OAC, though these data are insufficient for translation to current clinical practice. Well-designed prospective studies are now required to validate their role in stratified and personalised RT treatment approaches.


Asunto(s)
Biomarcadores de Tumor , Neoplasias Esofágicas , Humanos , Neoplasias Esofágicas/radioterapia , Neoplasias Esofágicas/sangre , Neoplasias Esofágicas/patología , Neoplasias Esofágicas/mortalidad , Biomarcadores de Tumor/sangre , Pronóstico , Medicina de Precisión , Adenocarcinoma/radioterapia , Adenocarcinoma/sangre , Adenocarcinoma/mortalidad
6.
Nat Commun ; 15(1): 2476, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38509088

RESUMEN

Cellular entry of the hepatitis B and D viruses (HBV/HDV) requires binding of the viral surface polypeptide preS1 to the hepatobiliary transporter Na+-taurocholate co-transporting polypeptide (NTCP). This interaction can be blocked by bulevirtide (BLV, formerly Myrcludex B), a preS1 derivative and approved drug for treating HDV infection. Here, to elucidate the basis of this inhibitory function, we determined a cryo-EM structure of BLV-bound human NTCP. BLV forms two domains, a plug lodged in the bile salt transport tunnel of NTCP and a string that covers the receptor's extracellular surface. The N-terminally attached myristoyl group of BLV interacts with the lipid-exposed surface of NTCP. Our structure reveals how BLV inhibits bile salt transport, rationalizes NTCP mutations that decrease the risk of HBV/HDV infection, and provides a basis for understanding the host specificity of HBV/HDV. Our results provide opportunities for structure-guided development of inhibitors that target HBV/HDV docking to NTCP.


Asunto(s)
Hepatitis B , Lipopéptidos , Simportadores , Humanos , Virus de la Hepatitis B/fisiología , Antivirales/uso terapéutico , Receptores Virales/metabolismo , Ácidos y Sales Biliares/metabolismo , Virus de la Hepatitis Delta/fisiología , Simportadores/metabolismo , Internalización del Virus , Hepatocitos/metabolismo
7.
Clin Nutr ESPEN ; 58: 277-294, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-38057018

RESUMEN

PURPOSE (BACKGROUND): The presented review is an updating of Iron metabolism in context of normal physiology and pathological phases. Iron is one of the vital elements in humans and associated into proteins as a component of heme (e.g. hemoglobin, myoglobin, cytochromes proteins, myeloperoxidase, nitric oxide synthetases), iron sulfur clusters (e.g. respiratory complexes I-III, coenzyme Q10, mitochondrial aconitase, DNA primase), or other functional groups (e.g. hypoxia inducible factor prolyl hydroxylases). All these entire iron-containing proteins ar e needed for vital cellular and organismal functions together with oxygen transport, mitochondrial respiration, intermediary and xenobiotic metabolism, nucleic acid replication and repair, host defense, and cell signaling. METHODS (METABOLIC STRATEGIES): Cells have developed metabolic strategies to import and employ iron safely. Regulatory process of iron uptake, storage, intracellular trafficking and utilization is vital for the maintenance of cellular iron homeostasis. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. The predominant organs, which are associated in the metabolism of iron, are intestine, liver, bone marrow and spleen. Iron is conserved, recycled and stored. The reduced bioavailability of iron in humans has developed extremely efficient mechanisms for iron conservation. Prominently, the losses of iron cannot considerably enhance through physiologic mechanisms, even if iron intake and stores become excessive. Loss of iron is balanced or maintained from dietary sources. RESULTS (OUTCOMES): Numerous physiological abnormalities are associated with impaired iron metabolism. These abnormalities are appeared in the form of several diseases. There are duodenal ulcer, inflammatory bowel disease, sideroblastic anaemia, congenital dyserythropoietic anemias and low-grade myelodysplastic syndromes. Hereditary hemochromatosis and anaemia are two chronic diseases, which are responsible for disturbing the iron metabolism in various tissues, including the spleen and the intestine. Impairment in hepatic hepcidin synthesis is responsible for chronic liver disease, which is grounding from alcoholism or viral hepatitis. This condition directs to iron overload that can cause further hepatic damage. Iron has important role in several infectious diseases are tuberculosis, malaria trypanosomatid diseases and acquired immunodeficiency syndrome (AIDS). Iron is also associated with Systemic lupus erythematosus [SLE], cancer, Alzheimer's disease (AD) and post-traumatic epilepsy. CONCLUSION: Recently, numerous research studies are gradually more dedicated in the field of iron metabolism, but a number of burning questions are still waiting for answer. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. Increased information of the physiology of iron homeostasis will support considerate of the pathology of iron disorders and also make available the support to advance treatment.


Asunto(s)
Hemocromatosis , Sobrecarga de Hierro , Hepatopatías , Humanos , Hierro/metabolismo , Hemocromatosis/genética , Homeostasis/fisiología
8.
BMJ Open ; 13(9): e068906, 2023 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-37709321

RESUMEN

INTRODUCTION: Online adaptive MR-guided radiotherapy allows for dose escalation to pancreatic cancer while sparing surrounding critical organs. We seek to evaluate the safety of delivering hypofractionated five-fraction, three-fraction and single-fraction MR-guided stereotactic ablative radiotherapy (SABR) to the pancreas. METHODS AND ANALYSIS: This is a single-centre three-arm phase 1 non-randomised safety study. Patients with localised pancreatic cancer will receive either 50 Gy in five (biological equivalent dose (BED10)=100 Gy), 39 Gy in three (BED10=90 Gy) or 25 Gy in a single fraction (BED10=87.5 Gy) MR-guided daily online adaptive radiotherapy. Each fractionation regimen will be assessed as independent cohorts to determine tolerability, assessed continuously using Bayesian conjugate posterior beta distributions. The primary endpoint of the study is to establish the safety of five-fraction, three-fraction and single-fraction MR-guided hypofractionation SABR in localised pancreatic cancer by assessing dose-limiting toxicities. Secondary endpoints include overall survival, progression-free survival, local control rates, overall control rate, resection rates, long-term toxicities and freedom from second-line chemotherapy. This study plans to also explore imaging and immune biomarkers that may be useful to predict outcome and personalise treatment. The trial will recruit up to 60 patients with a safety run-in. ETHICS AND DISSEMINATION: The trial is approved by the West Midlands-Black Country Research Ethics Committee 22/WM/0122. The results will be disseminated via conference presentations, peer-reviewed scientific journals and submission to regulatory authorities. The data collected for the study, including individual participant data, will be made available to researchers on request to the study team and with appropriate reason, via octo-enquiries@oncology.ox.ac.uk. The shared data will be deidentified participant data and will be available for 3 years following publication of the study. Data will be shared with investigator support, after approval of a proposal and with a signed data access agreement. TRIAL REGISTRATION NUMBER: ISRCTN10557832.


Asunto(s)
Neoplasias Pancreáticas , Hipofraccionamiento de la Dosis de Radiación , Humanos , Teorema de Bayes , Páncreas , Neoplasias Pancreáticas/radioterapia , Hospitales Universitarios , Reino Unido , Ensayos Clínicos Fase I como Asunto , Neoplasias Pancreáticas
9.
Nat Commun ; 14(1): 5774, 2023 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-37723174

RESUMEN

The organic anion transporting polypeptides OATP1B1 and OATP1B3 are membrane proteins that mediate uptake of drugs into the liver for subsequent conjugation and biliary excretion, a key step in drug elimination from the human body. Polymorphic variants of these transporters can cause reduced drug clearance and adverse drug effects such as statin-induced rhabdomyolysis, and co-administration of OATP substrates can lead to damaging drug-drug interaction. Despite their clinical relevance in drug disposition and pharmacokinetics, the structure and mechanism of OATPs are unknown. Here we present cryo-EM structures of human OATP1B1 and OATP1B3 bound to synthetic Fab fragments and in functionally distinct states. A single estrone-3-sulfate molecule is bound in a pocket located in the C-terminal half of OATP1B1. The shape and chemical nature of the pocket rationalize the preference for diverse organic anions and allow in silico docking of statins. The structure of OATP1B3 is determined in a drug-free state but reveals a bicarbonate molecule bound to the conserved signature motif and a histidine residue that is prevalent in OATPs exhibiting pH-dependent activity.


Asunto(s)
Transportador 1 de Anión Orgánico Específico del Hígado , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones Orgánicos , Humanos , Transporte Biológico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Proteínas de Transporte de Membrana , Transportador 1 de Anión Orgánico Específico del Hígado/química , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones Orgánicos/química
10.
Hematol., Transfus. Cell Ther. (Impr.) ; 45(3): 342-349, July-Sept. 2023. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1514178

RESUMEN

ABSTRACT Introduction: The knowledge of clinicians regarding blood transfusion services may impact patient care and transfusion outcome. The wide variation in transfusion practices among clinicians leads to inappropriate blood product usage and jeopardizes patient safety. Hence, this survey study aimed to assess knowledge, attitude and practice among the residents and interns of safe blood transfusion. Methods: The online survey was based on self-administered questionnaires of three sections: 1. Demography; 2. Knowledge, and; 3. Attitude and Practice. One point was assigned for the correct response of each question in every section. The knowledge score was further categorized into three categories, depending on the points obtained. The participants were also divided into four groups, depending on their experience. The Kruskal-Wallis test was applied to determine the difference of knowledge and practice scores in three designated groups of residents and interns. A p-value of less than 0.05 was considered to be significant. Result: A total of 247 residents and interns participated in this study. Thirteen participants had an incomplete response. Out of 234 participants, Senior Residents (SR), Junior Residents (JR), and interns were 70, 96 and 68 participants, respectively. The knowledge scores of interns were significantly low, as compared to SRs and JRs. Practice scores of interns were also significantly low, compared to the JRs. However, most of the residents and interns (85%) were aware of the pre-transfusion testing. Conclusion: Therefore, the mandatory incorporation of the transfusion medicine subject in the undergraduate curriculum can help the young budding doctors to better implement the patient blood management.


Asunto(s)
Reacción a la Transfusión
11.
Lab Med ; 54(6): e197-e200, 2023 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-37527552

RESUMEN

The Rh-D negative pregnancy is commonly associated with alloimmunization against D-antigen. It can be prevented by anti-D prophylaxis in pregnant patients with negative results on antibody screening. Hence, it is essential to exclude alloantibody-D in the presence of multiple alloantibodies. Anti-G antibody is formed after exposure to G antigen in neonate RBCs. Blood-group discrepancy was noted in reverse grouping, and antibody-screening results were positive in our case individual, a 28-year old Odiya Indian woman. We performed antibody identification on serum specimens from this patient, which revealed the pattern of anti-D + anti-C antibody specificity. Blood-group discrepancy was solved using rr (ce/ce)-phenotype pooled cells for reverse grouping. We identified anti-G antibodies by themselves without anti-D and anti-C after performing sequential adsorption of serum with r'r' (Ce/Ce) and R2R2 (DcE/DcE) group-O RBCs in the mother, who had rr phenotype and primigravida designation. After completing antibody screening at the first antenatal check-up, we recommended prophylactic anti-D for the mother in any future pregnancies she may have.


Asunto(s)
Isoanticuerpos , Sistema del Grupo Sanguíneo Rh-Hr , Recién Nacido , Humanos , Femenino , Embarazo , Adulto , Eritrocitos , Globulina Inmune rho(D) , Sistema del Grupo Sanguíneo ABO
12.
Diabetes Ther ; 14(10): 1695-1709, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37561266

RESUMEN

BACKGROUND: In India, around 77 million people are at high risk of developing type 2 diabetes mellitus (T2DM). Yoga interventions can be effective in preventing T2DM. We conducted a feasibility randomized controlled trial (RCT) in India, and the intervention was the Yoga Programme for T2DM Prevention (YOGA-DP). This study aimed to identify and explore the facilitators and challenges in conducting the feasibility trial in India, and more specifically, to explore the perceptions and experiences of trial staff in relation to running the feasibility trial and Yoga instructors in relation to delivering the intervention. METHODS: An exploratory qualitative study was conducted at two trial sites in India (Yoga centers in New Delhi and Bengaluru). Semi-structured interviews were conducted with ten participants (six trial staff and four Yoga instructors) to explore their perceptions and experiences related to the study's aim. Data were analyzed using deductive as well as inductive logic and an interpretative phenomenological approach. RESULTS: Feasibility-trial-related facilitators were useful participant recruitment strategies and help and support received from the trial coordination center. Intervention-related facilitators were strengths of the intervention content, structure, and delivery (including materials) and competencies of Yoga instructors. Feasibility-trial-related challenges were lack of awareness about T2DM among potential participants, stigma and fear associated with T2DM among potential participants, difficulties in explaining the research and obtaining written informed consent from potential participants, expectations and demands of potential participants and control-group participants, gender and language issues in participant recruitment, other participant recruitment-related challenges, issues in participant follow-up, and issues in data collection and trial documentation. Intervention-related challenges were the limited interest of participants in Yoga, participants' time constraints on practicing Yoga, participants' health issues hindered Yoga practice, beginners' difficulties with practicing Yoga, participants' demotivation to practice Yoga at home, issues with the Yoga practice venue, confusion regarding the intervention structure, issues with intervention materials, and the incompetence of Yoga instructors. CONCLUSIONS: The perceptions and experiences of trial staff and Yoga instructors helped us to understand the facilitators and challenges in running a feasibility trial and delivering the intervention for T2DM prevention, respectively. These findings and their suggestions will be used when designing the definitive RCT for evaluating YOGA-DP's effectiveness, and may be helpful to researchers planning similar trials. TRIAL REGISTRATION NUMBER: India (CTRI) CTRI/2019/05/018893.

13.
bioRxiv ; 2023 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-37502840

RESUMEN

Atypical chemokine receptor 3 (ACKR3, also known as CXCR7) is a scavenger receptor that regulates extracellular levels of the chemokine CXCL12 to maintain responsiveness of its partner, the G protein-coupled receptor (GPCR), CXCR4. ACKR3 is notable because it does not couple to G proteins and instead is completely biased towards arrestins. Our previous studies revealed that GRK2 and GRK5 install distinct distributions of phosphates (or "barcodes") on the ACKR3 carboxy terminal tail, but how these unique barcodes drive different cellular outcomes is not understood. It is also not known if arrestin2 (Arr2) and 3 (Arr3) bind to these barcodes in distinct ways. Here we report cryo-electron microscopy structures of Arr2 and Arr3 in complex with ACKR3 phosphorylated by either GRK2 or GRK5. Unexpectedly, the finger loops of Arr2 and 3 directly insert into the detergent/membrane instead of the transmembrane core of ACKR3, in contrast to previously reported "core" GPCR-arrestin complexes. The distance between the phosphorylation barcode and the receptor transmembrane core regulates the interaction mode of arrestin, alternating between a tighter complex for GRK5 sites and heterogenous primarily "tail only" complexes for GRK2 sites. Arr2 and 3 bind at different angles relative to the core of ACKR3, likely due to differences in membrane/micelle anchoring at their C-edge loops. Our structural investigations were facilitated by Fab7, a novel Fab that binds both Arr2 and 3 in their activated states irrespective of receptor or phosphorylation status, rendering it a potentially useful tool to aid structure determination of any native GPCR-arrestin complex. The structures provide unprecedented insight into how different phosphorylation barcodes and arrestin isoforms can globally affect the configuration of receptor-arrestin complexes. These differences may promote unique downstream intracellular interactions and cellular responses. Our structures also suggest that the 100% bias of ACKR3 for arrestins is driven by the ability of arrestins, but not G proteins, to bind GRK-phosphorylated ACKR3 even when excluded from the receptor cytoplasmic binding pocket.

14.
J Phys Chem Lett ; 14(31): 6968-6976, 2023 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-37506173

RESUMEN

Highly concentrated aqueous electrolytes have attracted attention due to their unique applications in lithium ion batteries (LIBs). However, the solvation structure and transport mechanism of Li+ cations at concentrated concentrations remain largely unexplored. To address this gap in knowledge, we employ ultrafast infrared spectroscopy and molecular dynamics (MD) simulations to reveal the dynamic and spatial structural heterogeneity in aqueous lithium chloride (LiCl) solutions. The coupling between the reorientation dynamics of the extrinsic probe and the macroscopic viscosity in aqueous LiCl solutions was analyzed using the Stokes-Einstein-Debye (SED) equations. MD simulations reveal that the Cl- and Li+ form chain-like structures through electrostatic interactions, supporting the vehicular migration of Li+ through the chain-like structure. The concentration dependent conductivity of the LiCl solution is well reproduced, where Li(H2O)2+ and Li(H2O)3+ are the dominant species that contribute to the conduction of Li+. This study is expected to establish correlations between ion pair structures and macroscopic properties.

15.
ACS Chem Biol ; 18(8): 1760-1771, 2023 08 18.
Artículo en Inglés | MEDLINE | ID: mdl-37449780

RESUMEN

Non-enzymatic posttranslational modifications are believed to affect at least 30% of human proteins, commonly termed glycation. Many of these modifications are implicated in various pathological conditions, e.g., cataract, diabetes, neurodegenerative diseases, and cancer. Chemical protein synthesis enables access to full-length proteins carrying site-specific modifications. One such modification, argpyrimidine (Apy), has been detected in human small heat shock protein Hsp27 and closely related proteins in patient-derived tissues. Thus far, studies have looked into only artificial mixtures of Apy modifications, and only one has analyzed Apy188. We were interested in understanding the impact of such individual Apy modifications on five different arginine sites within the crucial N-terminal domain of Hsp27. By combining protein semisynthesis with biochemical assays on semisynthetic Hsp27 analogues with single-point Apy modification at those sites, we have shown how a seemingly minimal modification within this region results in dramatically altered functional attributes.


Asunto(s)
Proteínas de Choque Térmico , Reacción de Maillard , Humanos , Pliegue de Proteína , Procesamiento Proteico-Postraduccional
16.
EClinicalMedicine ; 61: 102059, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37409323

RESUMEN

Background: The utility of early metabolic response assessment to guide selection of the systemic component of definitive chemoradiotherapy (dCRT) for oesophageal cancer is uncertain. Methods: In this multi-centre, randomised, open-label, phase II substudy of the radiotherapy dose-escalation SCOPE2 trial we evaluated the role of 18F-Fluorodeoxyglucose positron emission tomography (PET) at day 14 of cycle 1 of three-weekly induction cis/cap (cisplatin (60 mg/m2)/capecitabine (625 mg/m2 days 1-21)) in patients with oesophageal squamous cell carcinoma (OSCC) or adenocarcinoma (OAC). Non-responders, who had a less than 35% reduction in maximum standardised uptake value (SUVmax) from pre-treatment baseline, were randomly assigned to continue cis/cap or switch to car/pac (carboplatin AUC 5/paclitaxel 175 mg/m2) for a further induction cycle, then concurrently with radiotherapy over 25 fractions. Responders continued cis/cap for the duration of treatment. All patients (including responders) were randomised to standard (50Gy) or high (60Gy) dose radiation as part of the main study. Primary endpoint for the substudy was treatment failure-free survival (TFFS) at week 24. The trial was registered with International Standard Randomized Controlled Trial Number 97125464 and ClinicalTrials.govNCT02741856. Findings: This substudy was closed on 1st August 2021 by the Independent Data Monitoring Committee on the grounds of futility and possible harm. To this point from 22nd November 2016, 103 patients from 16 UK centres had participated in the PET-CT substudy; 63 (61.2%; 52/83 OSCC, 11/20 OAC) of whom were non-responders. Of these, 31 were randomised to car/pac and 32 to remain on cis/cap. All patients were followed up until at least 24 weeks, at which point in OSCC both TFFS (25/27 (92.6%) vs 17/25 (68%); p = 0.028) and overall survival (42.5 vs. 20.4 months, adjusted HR 0.36; p = 0.018) favoured cis/cap over car/pac. There was a trend towards worse survival in OSCC + OAC cis/cap responders (33.6 months; 95%CI 23.1-nr) vs. non-responders (42.5 (95%CI 27.0-nr) months; HR = 1.43; 95%CI 0.67-3.08; p = 0.35). Interpretation: In OSCC, early metabolic response assessment is not prognostic for TFFS or overall survival and should not be used to personalise systemic therapy in patients receiving dCRT. Funding: Cancer Research UK.

17.
Transfusion ; 63(9): 1747-1757, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37427683

RESUMEN

BACKGROUND: Red Blood cells (RBCs) bring about harmful consequences during storage. MicroRNA (miRNA) dysregulation in stored RBCs could represent potential biomarkers of storage lesions. Although leukoreduction prevents damage to RBCs, it is uncertain whether leukoreduction of RBCs would impact the dysregulation of miRNAs during storage. This study evaluated the potential role of miRNAs for any alteration of leukoreduced (LR) and non-leukoreduced (NLR) RBCs till 21 days of storage. STUDY DESIGN AND METHODS: In this prospective study, thirty male volunteers' blood was equally divided into leukoreduced RBCs (LR) and NLR RBC (NLR) bags and stored till Day 21 at 4-60c. Selected miRNAs were quantified on Days 0 and 21. Further, bioinformatic tools were used to analyze the selected miRNAs and their predicted target genes (mRNAs) and identify the miRNA-mRNA regulatory relationships. RESULTS: A significantly higher fold change values of three miRNAs (miR-96-5p, miR-197-3p, miR-769-3p) were observed in NLR RBCs (p < .05). A significantly higher (p < .05) expression levels of miR-150-5p and miR-197-3p were observed in NLR RBCs till 21 days of storage. Further, the correlation with mRNA quantification confirmed the regulatory role of these miRNAs upon functional pathway enrichment analysis. DISCUSSION: A higher level of dysregulation of miRNAs was observed in NLR RBCs. Validation from In-Silico analysis suggested the regulatory role of miRNAs in cell apoptosis, senescence, and RBC-related signaling pathways. This indicated that stored LR RBCs would likely have better in vivo survival and function following transfusion. However, an in vivo study of miRNA in RBCs is warranted for conclusive evidence.


Asunto(s)
MicroARNs , Humanos , Masculino , MicroARNs/metabolismo , Conservación de la Sangre , Estudios Prospectivos , Eritrocitos/metabolismo
18.
Transfus Clin Biol ; 30(3): 329-334, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37321533

RESUMEN

INTRODUCTION: Cryoprecipitate is used in conditions like hypofibrinogenemia, massive transfusion with bleeding, and factor XIII deficiency. The current guidelines support the preparation of cryoprecipitate from 450 ml whole blood. But 350 ml of whole blood collection is expected from low body weight (<55 kg) donors. However, no standardized criteria exist for preparing cryoprecipitate from 350 ml of whole blood. AIM OF THE STUDY: This study compared the fibrinogen and factor VIII levels in cryoprecipitate units prepared from 350 ml versus 450 ml whole blood collection. The study also compared the fibrinogen and factor VIII levels prepared by circulating water bath versus blood bank refrigerator (BBR) thawing method. METHODOLOGY: A total of 128 blood bags were equally divided into groups A and B for 450 and 350 ml whole blood collection further subdivided into subgroups based on thawing methods. The fibrinogen and factor VIII yield were analyzed in the cryoprecipitates prepared from both groups. RESULTS: The factor VIII levels were significantly higher in cryoprecipitate made from 450 ml whole blood collection (P = 0.02). The BBR method of plasma thawing resulted in better fibrinogen recovery than the cryo bath method. Whereas vice versa in the case of factor VIII recovery. A weak but significant positive correlation was noted in factor VIII levels with the plasma volume. CONCLUSION: Over 75% of the cryoprecipitates prepared from 350 ml whole blood passed the fibrinogen and factor VIII quality control criteria. So, 350 ml whole blood collection from low body weight (<55 kg) donors could be utilized to prepare cryoprcipitates. However, future clinical studies should focus on the cryoprecipitate's clinical efficacy prepared from 350 ml of whole blood.


Asunto(s)
Factor VIII , Hemostáticos , Humanos , Factor VIII/uso terapéutico , Fibrinógeno/análisis , Plasma , Peso Corporal
19.
Biochem Biophys Res Commun ; 672: 45-53, 2023 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-37336124

RESUMEN

Secretory proteins are used by pathogenic bacteria to manipulate the host systems and compete with other microorganisms, thereby enabling their survival in their host. Similar to other bacteria, secretory proteins of Mycobacterium tuberculosis also play a pivotal role in evading immune response within hosts, thereby leading to acute and latent tuberculosis infection. Prokaryotes have several classes of bacterial secretory systems out of which the Sec and Tat pathways are the most conserved in Mtb to transport proteins across the cytoplasmic membrane. Here, we report the crystal structure of a secretory protein, Rv0398c determined to 1.9 Å resolution. The protein comprises a core of antiparallel ß sheets surrounded by α helices adopting a unique ß sandwich fold. Structural comparison with other secretory proteins in Mtb and other pathogenic bacteria reveals that Rv0398c may be secreted via the Sec pathway. Our structural and in silico analyses thus provide mechanistic insights into the pathway adopted by Mtb to transport out secretory protein, Rv0398c which will facilitate the invasion to the host immune system.


Asunto(s)
Proteínas Bacterianas , Mycobacterium tuberculosis , Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Mycobacterium tuberculosis/metabolismo , Proteínas Portadoras/metabolismo , Transporte Biológico
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA