Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87
Filtrar
1.
Inflamm Bowel Dis ; 2024 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-39177975

RESUMO

Diet therapy for inflammatory bowel disease (IBD) is an international research priority but guidance for IBD-specific diet trial design is lacking. This review critically evaluates key elements of prospective IBD food-based intervention trials and identifies gaps. Electronic databases were searched for interventional IBD diet studies. Prospective primary studies/trials were included if used food-based dietary strategies. Forty studies/trials evaluating 29 food-based strategies as therapy for IBD were identified. Considerable heterogeneity in diets, trial design, and methodology exists. Thirty-one trials (78%) intended the diet to modulate inflammation but 14/31 (46%) did not have a primary endpoint measuring an objective change in inflammatory activity and 20/31 (65%) controlled for medication stability prior to application of diet at baseline. Higher-quality IBD diet trials used symptom-based assessment tools coupled with an objective evaluation of inflammatory activity. Dietary advice trials are the most common. One-third of trials developed and administered diet education without a dietitian. Evaluation and reporting on adherence to diet therapy occurred in <60% of trials. Failure to include or report on key elements of trial design reduced the interpretability and validity of the results. This is a considerable limitation to advancing scientific knowledge in this area. Diet therapy trials should adhere to similar rigorous quality standards used to develop other IBD therapies. Therefore, a set of practical recommendations was generated to provide the authors' perspective to help inform the future design of high-quality IBD diet trials.


High-quality inflammatory bowel disease (IBD) diet trials are lacking and existing trials are fraught with methodological flaws. This review is intended to assist clinician-researchers in the design and conduct of future food-based intervention trials to raise the quality of IBD diet research.

2.
Orthopedics ; : 1-5, 2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39163603

RESUMO

BACKGROUND: The purpose of this study was to externally validate a predictive score for fracture-related infections, establishing generalizability for absolute and relative risk of infection in the setting of orthopedic fracture surgery. MATERIALS AND METHODS: This was a retrospective, case-control study performed at a level I academic trauma center that included 147 patients with fracture-related infection in the study group and 300 control patients. We analyzed the same 8 independent predictors of fracture-related infection cited by a previous study. We then used the area under the receiver operating characteristics curve (AUC) to compare the derivation and validation cohorts. The validation and derivation cohorts were then compared by grouping patients into 4 strata of Wise score groups. This allowed for comparison of AUC and risk of fracture-related infection in our institution with those in the previously studied institution. RESULTS: The resulting data yielded an AUC (0.74) nearly identical to that of the previously studied institution. It was also found that the relative risk of infection correlated with the Wise score in the same way the initial model did with the absolute risks being similar. CONCLUSION: The previous predictive model was externally validated and shown to be generalizable to a different patient population. The relative risk of a fracture-related infection can be determined using this scoring model preoperatively with the goal of aiding in patient counseling and surgical decision-making, giving a quantitative value to patient risk factors. [Orthopedics. 202x;4x(x):xx-xx.].

3.
Mil Med ; 189(Supplement_3): 99-105, 2024 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-39160800

RESUMO

INTRODUCTION: Definitive management of non-compressible intra-abdominal hemorrhage (NCIAH) currently requires a surgeon and operating room capable of performing damage control surgery. In a wartime scenario or a geographically remote environment, these may not be readily available. In this study, we sought to test the safety of 2 emerging injectable hemostatic agents (CounterFlow and Fast Onset Abdominal Management, or FOAM, poloxamer component) versus normal saline control over a prolonged monitoring duration following administration by a non-surgical provider. MATERIALS AND METHODS: The Institutional Animal Care and Use Committee approved all research conducted in this study. We randomized male New Zealand white rabbits into 2 monitoring cohorts of 24 hours and 2 weeks. Each cohort contained 3 treatment groups (n = 4 rabbits/group): CounterFlow, the testable poloxamer component of FOAM, and normal saline control. We injected each treatment intraperitoneally in the left lower abdominal quadrant. Doses were 15 mL/kg for CounterFlow, 6.3 mL/kg for the poloxamer component of FOAM, and 15 mL/kg for normal saline. We conducted all injections under isoflurane anesthesia monitored by trained veterinary staff. Animals were euthanized at each cohort end point, and a veterinary pathologist blinded to treatment type performed necropsy. The primary outcome was incidence of intra-abdominal adhesions at necropsy. Quantitatively, adhesions when present were graded by the veterinary pathologist on a 1 to 4 scale, where "1" represented adhesions involving from 1 to 25% of the examined abdomen, "2" represented from 26 to 50%, "3" represented from 51 to 75%, and "4" represented from 76 to 100%. Qualitatively, adhesions present were graded by degree ("1" = minimal, "2" = mild, "3" = moderate, and "4" = severe) and chronicity ("1" = acute, "2" = subacute, and "3" = chronic). We also drew d-dimer blood values and measured body weights for each animal. Statistical analysis included either repeated measures 2-way ANOVA or a mixed-effects model (in the case of missing data) with Geisser-Greenhouse correction. We adjusted multiple comparisons using Tukey statistical hypothesis tests. RESULTS: In the 2-week cohort, 3 CounterFlow animals showed adhesions judged to be "1" quantitatively. Qualitatively, 2 of these were assessed as "1" for degree of adhesions and the other demonstrated a "2." On the chronicity of adhesions scale, 1 animal demonstrated a "2" and 2 demonstrated a "3." No animals in other groups (FOAM and control) demonstrated adhesions. CounterFlow-treated animals showed a statistically significant rise in d-dimer values in the 24-hour cohort only. In the 2-week cohort, CounterFlow-treated animals showed a decrease in body weight at 24 hours after injection but returned to their baseline (normal) body weights at 7 days. CONCLUSIONS: Findings from this study demonstrate that the tested ingredients of FOAM poloxamer component are safe for intraperitoneal injection and hold potential for further study directed toward prehospital non-compressible intra-abdominal hemorrhage management by non-surgical providers. Although CounterFlow produced abdominal adhesions in 3 of 4 rabbits in the 2-week cohort, these were determined to be "minimal" or "mild" in degree.


Assuntos
Hemostáticos , Animais , Coelhos , Aderências Teciduais , Masculino , Hemostáticos/administração & dosagem , Injeções Intraperitoneais , Poloxâmero/efeitos adversos , Poloxâmero/administração & dosagem , Incidência , Abdome/cirurgia
4.
Proc Natl Acad Sci U S A ; 121(34): e2315009121, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39133860

RESUMO

The enzyme UDP-glucose: glycoprotein glucosyltransferase (UGGT) is the gatekeeper of protein folding within the endoplasmic reticulum (ER). One-third of the human proteome traverses the ER where folding and maturation are facilitated by a complex protein homeostasis network. Both glycan modifications and disulfide bonds are of key importance in the maturation of these ER proteins. The actions of UGGT are intimately linked to the glycan code for folding and maturation of secretory proteins in the ER. UGGT selectively glucosylates the N-linked glycan of misfolded proteins so that they can reenter the lectin-folding chaperone cycle and be retained within the ER for further attempts at folding. An intriguing aspect of UGGT function is its interaction with its poorly understood cochaperone, the 15 kDa selenoprotein known as SELENOF or SEP15. This small protein contains a rare selenocysteine residue proposed to act as an oxidoreductase toward UGGT substrates. AlphaFold2 predictions of the UGGT1/SEP15 complex provide insight into this complex at a structural level. The predicted UGGT1/SEP15 interaction interface was validated by mutagenesis and coimmunoprecipitation experiments. These results serve as a springboard for models of the integrated action of UGGT1 and SEP15.


Assuntos
Retículo Endoplasmático , Glucosiltransferases , Dobramento de Proteína , Selenoproteínas , Selenoproteínas/metabolismo , Selenoproteínas/genética , Retículo Endoplasmático/metabolismo , Humanos , Glucosiltransferases/metabolismo , Glucosiltransferases/genética , Ligação Proteica
5.
Genetics ; 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39110836

RESUMO

Cohesins promote proper chromosome segregation, gene transcription, genomic architecture, DNA condensation, and DNA damage repair. Mutations in either cohesin subunits or regulatory genes can give rise to severe developmental abnormalities (such as Robert Syndrome and Cornelia de Lange Syndrome) and also are highly correlated with cancer. Despite this, little is known about cohesin regulation. Eco1 (ESCO2/EFO2 in humans) and Rad61 (WAPL in humans) represent two such regulators but perform opposing roles. Eco1 acetylation of cohesin during S phase, for instance, stabilizes cohesin-DNA binding to promote sister chromatid cohesion. On the other hand, Rad61 promotes the dissociation of cohesin from DNA. While Eco1 is essential, ECO1 and RAD61 co-deletion results in yeast cell viability, but only within a limited temperature range. Here, we report that eco1 rad61 cell lethality is due to reduced levels of the cohesin subunit Mcd1. Results from a suppressor screen further reveals that FDO1 deletion rescues the temperature sensitive (ts) growth defects exhibited by eco1 rad61 double mutant cells by increasing Mcd1 levels. Regulation of MCD1 expression, however, appears more complex. Elevated expression of MBP1, which encodes a subunit of the MBF transcription complex, also rescues eco1 rad61 cell growth defects. Elevated expression of SWI6, however, which encodes the Mbp1-binding partner of MBF, exacerbates eco1 rad61 cell growth and also abrogates the Mpb1-dependent rescue. Finally, we identify two additional transcription factors, Fkh1 and Fkh2, that impact MCD1 expression. In combination, these findings provide new insights into the nuanced and multi-faceted transcriptional pathways that impact MCD1 expression.

6.
Gynecol Oncol ; 189: 129-136, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39116830

RESUMO

OBJECTIVES: To determine if nutritional status effects response to immunotherapy in women with gynecologic malignancies. METHODS: A retrospective chart review was conducted on gynecologic cancer patients who received immunotherapy at a single institution between 2015 and 2022. Immunotherapy included checkpoint inhibitors and tumor vaccines. The prognostic nutritional index (PNI) was calculated from serum albumin levels and total lymphocyte count. PNI values were determined at the beginning of treatment for each patient and assessed for their association with immunotherapy response. Disease control response (DCR) as an outcome of immunotherapy was defined as complete response, partial response, or stable disease. RESULTS: One hundred and ninety-eight patients received immunotherapy (IT) between 2015 and 2022. The gynecological cancers treated were uterine (38%), cervix (32%), ovarian (25%), and vulvar or vaginal (4%) cancers. The mean PNI for responders was higher than the non-responder group (p < 0.05). The AUC value for PNI as a predictor of response was 49. A PNI value of 49 was 43% sensitive and 85% specific for predicting a DCR. In Cox proportional hazards analysis, after adjusting for ECOG score and the number of prior chemotherapy lines, severe malnutrition was associated with progression-free survival (PFS) (HR = 1.85, p = 0.08) and overall survival (OS) (HR = 3.82, p < 0.001). Patients with PNI < 49 were at a higher risk of IT failure (HR = 2.24, p = 0.0001) and subsequent death (HR = 2.84, p = 9 × 10-5). CONCLUSIONS: PNI can be a prognostic marker to predict response rates of patients with gynecologic cancers treated with immunotherapy. Additional studies needed to understand the mechanistic role of malnutrition in immunotherapy response.

7.
Stud Mycol ; 108: 1-411, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39100921

RESUMO

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Blaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilanski P, Bradley CA, Bubner B, Burgess TI, Buyck B, Cadez N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

8.
Appl Spectrosc ; : 37028241270637, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39094000

RESUMO

The development of non-contact in situ techniques for monitoring of cure kinetics has the potential to greatly improve both resin formulation and processing. We have recently shown that low-frequency Raman spectroscopy is a viable method for assessing resin structural cure kinetics and complements the traditional chemical conversion determined from the fingerprint region of the spectrum. In this work we further evaluate the relationship between the structural and chemical conversion by investigating two chemically identical yet rheologically different interpenetrating polymer network resin formulations. Rheological analysis demonstrates a relationship between structural conversion and storage modulus, which is not observed in the chemical conversion data. We show that one can produce master cure kinetics curves with comparable kinetic constants using both the chemical and structural conversion methodologies. Parametric analysis of the structural conversion, chemical conversion, and photorheological conversion was combined with a semi-empirical model for the storage shear modulus as a function of extent of cure.

9.
JGH Open ; 8(7): e13097, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38957480

RESUMO

Until recently, diet as a therapeutic tool to treat inflammatory bowel disease (IBD) has not been proven effective. Nearly a century in the making we are in the grips of a revolution in diet therapies for IBD, driven by emerging data revealing diet as a key environmental factor associated with IBD susceptibility, and observational studies suggesting that dietary intake may play a role in the disease course of established IBD. This review summarizes the current evidence for diets trialed as induction and maintenance therapy for IBD. For Crohn's disease, exclusive enteral nutrition and the Crohn's disease exclusion diet with partial enteral nutrition are supported by emerging high-quality evidence as induction therapy, but are short-term approaches that are not feasible for prolonged use. Data on diet as maintenance therapy for Crohn's disease are conflicting, with some studies supporting fortification, and others suppression, of certain food components. For ulcerative colitis, data are not as robust for diet as induction and maintenance therapy; however, consistent themes are emerging, suggesting benefits for diets that are plant-based, high in fiber and low in animal protein. Further studies for both Crohn's disease and ulcerative colitis are eagerly awaited, which will allow specific recommendations to be made. Until this time, recommendations default to population based healthy eating guidelines.

10.
J Am Geriatr Soc ; 2024 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-38970392

RESUMO

BACKGROUND: Modeled after the Physician Orders for Life Sustaining Treatment program, the Veterans Health Administration (VA) implemented the Life-Sustaining Treatment (LST) Decisions Initiative to improve end-of-life outcomes by standardizing LST preference documentation for seriously ill Veterans. This study examined the associations between LST documentation and family evaluation of care in the final month of life for Veterans in VA nursing homes. METHODS: Retrospective, cross-sectional analysis of data for decedents in VA nursing homes between July 1, 2018 and January 31, 2020 (N = 14,575). Regression modeling generated odds for key end-of-life outcomes and family ratings of care quality. RESULTS: LST preferences were documented for 12,928 (89%) of VA nursing home decedents. Contrary to our hypothesis, neither receipt of wanted medications and medical treatment (adjusted odds ratio [OR]: 0.85, 95% confidence interval [CI] 0.63, 1.16) nor ratings of overall care in the last month of life (adjusted OR: 0.96, 95% CI 0.76, 1.22) differed significantly between those with and without completed LST templates in adjusted analyses. CONCLUSIONS: Among Community Living Center (CLC) decedents, 89% had documented LST preferences. No significant differences were observed in family ratings of care between Veterans with and without documentation of LST preferences. Interventions aimed at improving family ratings of end-of-life care quality in CLCs should not target LST documentation in isolation of other factors associated with higher family ratings of end-of-life care quality.

11.
Methods Enzymol ; 700: 49-76, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38971612

RESUMO

High pressure is both an environmental challenge to which deep sea biology has to adapt, and a highly sensitive thermodynamic tool that can be used to trigger structural changes in biological molecules and assemblies. Lipid membranes are amongst the most pressure sensitive biological assemblies and pressure can have a large influence on their structure and properties. In this chapter, we will explore the use of high pressure small angle X-ray diffraction and high pressure microscopy to measure and quantify changes in the lateral structure of lipid membranes under both equilibrium high pressure conditions and in response to pressure jumps.


Assuntos
Pressão Hidrostática , Bicamadas Lipídicas , Difração de Raios X , Difração de Raios X/métodos , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Espalhamento a Baixo Ângulo , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Termodinâmica
12.
Res Pract Thromb Haemost ; 8(4): 102462, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-39006229

RESUMO

Background: Factor (F)XI deficiency is a rare bleeding disorder with a poor correlation between bleeding tendency and FXI level. Management of pregnant women with FXI deficiency is not clearly established, especially regarding neuraxial analgesia (NA). Objectives: A retrospective multicenter observational study was conducted in French hemostasis centers on pregnant women with FXI of <60 IU/dL. Methods: Data to report were (i) FXI levels before pregnancy and at time of delivery, (ii) type of NA and delivery management modalities, and (iii) possible complications related to NA and bleeding complications. Results: Three hundred fourteen pregnancies in patients with FXI deficiency of <60 IU/dL were reported (from 20 centers); among them, 199 NA procedures have been completed (137 epidurals and 61 spinals, 1 had both). The period of childbirth was mostly from 2014 to 2020 (281/314; 89.5%). Congenital FXI deficiency was established with certainty by investigators in 32.8% patients (n = 103). Previous bleedings were described in 20.4% of the patients (64/314; 45.3% cutaneous, 31.3% gynecologic, and 15.6% postsurgical). Thirteen deliveries had an NA procedure with FXI of <30 IU/dL, 42 with FXI of 30-40 IU/dL, and 118 with FXI of 40-60 IU/dL. Median FXI levels at delivery in the epidural and spinal groups were not significantly different but were significantly lower in the group without NA by medical staff contraindications. There were no complications related to NA. A 17.5% postpartum hemorrhage or excessive postpartum bleeding incidence was reported, which is consistent with previous data. Conclusion: Our data support the use of a 30 IU/dL FXI threshold for NA, as suggested by the French proposals published in August 2023.

13.
Viruses ; 16(7)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-39066199

RESUMO

Human immunodeficiency virus (HIV) and malaria, caused by infection with Plasmodium spp., are endemic in similar geographical locations. As a result, there is high potential for HIV/Plasmodium co-infection, which increases the pathology of both diseases. However, the immunological mechanisms underlying the exacerbated disease pathology observed in co-infected individuals are poorly understood. Moreover, there is limited data available on the impact of Plasmodium co-infection on antiretroviral (ART)-treated HIV infection. Here, we used the rhesus macaque (RM) model to conduct a pilot study to establish a model of Plasmodium fragile co-infection during ART-treated simian immunodeficiency virus (SIV) infection, and to begin to characterize the immunopathogenic effect of co-infection in the context of ART. We observed that P. fragile co-infection resulted in parasitemia and anemia, as well as persistently detectable viral loads (VLs) and decreased absolute CD4+ T-cell counts despite daily ART treatment. Notably, P. fragile co-infection was associated with increased levels of inflammatory cytokines, including monocyte chemoattractant protein 1 (MCP-1). P. fragile co-infection was also associated with increased levels of neutrophil elastase, a plasma marker of neutrophil extracellular trap (NET) formation, but significant decreases in markers of neutrophil degranulation, potentially indicating a shift in the neutrophil functionality during co-infection. Finally, we characterized the levels of plasma markers of gastrointestinal (GI) barrier permeability and microbial translocation and observed significant correlations between indicators of GI dysfunction, clinical markers of SIV and Plasmodium infection, and neutrophil frequency and function. Taken together, these pilot data verify the utility of using the RM model to examine ART-treated SIV/P. fragile co-infection, and indicate that neutrophil-driven inflammation and GI dysfunction may underlie heightened SIV/P. fragile co-infection pathogenesis.


Assuntos
Coinfecção , Inflamação , Macaca mulatta , Malária , Neutrófilos , Plasmodium , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia , Animais , Coinfecção/tratamento farmacológico , Coinfecção/parasitologia , Coinfecção/virologia , Malária/tratamento farmacológico , Malária/imunologia , Malária/complicações , Síndrome de Imunodeficiência Adquirida dos Símios/tratamento farmacológico , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/complicações , Projetos Piloto , Neutrófilos/imunologia , Antirretrovirais/uso terapêutico , Carga Viral , Biomarcadores/sangue , Citocinas/sangue , Modelos Animais de Doenças , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia
14.
J Elast ; 155(1-5): 269-303, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39035067

RESUMO

In materials that undergo martensitic phase transformation, macroscopic loading often leads to the creation and/or rearrangement of elastic domains. This paper considers an example involving a single-crystal slab made from two martensite variants. When the slab is made to bend, the two variants form a characteristic microstructure that we like to call "twinning with variable volume fraction." Two 1996 papers by Chopra et al. explored this example using bars made from InTl, providing considerable detail about the microstructures they observed. Here we offer an energy-minimization-based model that is motivated by their account. It uses geometrically linear elasticity, and treats the phase boundaries as sharp interfaces. For simplicity, rather than model the experimental forces and boundary conditions exactly, we consider certain Dirichlet or Neumann boundary conditions whose effect is to require bending. This leads to certain nonlinear (and nonconvex) variational problems that represent the minimization of elastic plus surface energy (and the work done by the load, in the case of a Neumann boundary condition). Our results identify how the minimum value of each variational problem scales with respect to the surface energy density. The results are established by proving upper and lower bounds that scale the same way. The upper bounds are ansatz-based, providing full details about some (nearly) optimal microstructures. The lower bounds are ansatz-free, so they explain why no other arrangement of the two phases could be significantly better.

15.
BMJ Open ; 14(7): e081787, 2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39032928

RESUMO

INTRODUCTION: A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring. METHODS AND ANALYSIS: The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants. ETHICS AND DISSEMINATION: Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment. TRIAL REGISTRATION NUMBER: ACTRN12622001458729.


Assuntos
Fármacos Gastrointestinais , Doenças Inflamatórias Intestinais , Infliximab , Humanos , Infliximab/administração & dosagem , Infliximab/uso terapêutico , Infliximab/farmacocinética , Doenças Inflamatórias Intestinais/tratamento farmacológico , Estudos Prospectivos , Fármacos Gastrointestinais/administração & dosagem , Fármacos Gastrointestinais/uso terapêutico , Injeções Subcutâneas , Administração Intravenosa , Estudos Multicêntricos como Assunto , Adulto , Austrália , Monitoramento de Medicamentos/métodos , Feminino , Masculino
16.
J Bone Joint Surg Am ; 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38954643

RESUMO

BACKGROUND: The Short Musculoskeletal Function Assessment (SMFA) is a well validated, widely used patient-reported outcome (PRO) measure for orthopaedic patients. Despite its widespread use and acceptance, this measure does not have an agreed upon minimal clinically important difference (MCID). The purpose of the present study was to create distributional MCIDs with use of a large cohort of research participants with severe lower extremity fractures. METHODS: Three distributional approaches were used to calculate MCIDs for the Dysfunction and Bother Indices of the SMFA as well as all its domains: (1) half of the standard deviation (one-half SD), (2) twice the standard error of measurement (2SEM), and (3) minimal detectable change (MDC). In addition to evaluating by patient characteristics and the timing of assessment, we reviewed these calculations across several injury groups likely to affect functional outcomes. RESULTS: A total of 4,298 SMFA assessments were collected from 3,185 patients who had undergone surgical treatment of traumatic injuries of the lower extremity at 60 Level-I trauma centers across 7 multicenter, prospective clinical studies. Depending on the statistical approach used, the MCID associated with the overall sample ranged from 7.7 to 10.7 for the SMFA Dysfunction Index and from 11.0 to 16.8 for the SMFA Bother Index. For the Dysfunction Index, the variability across the scores was small (<5%) within the sex and age subgroups but was modest (12% to 18%) across subgroups related to assessment timing. CONCLUSIONS: A defensible MCID can be found between 7 and 11 points for the Dysfunction Index and between 11 and 17 points for the Bother Index. The precise choice of MCID may depend on the preferred statistical approach and the population under study. While differences exist between MCID values based on the calculation method, values were consistent across the categories of the various subgroups presented. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

17.
Viruses ; 16(7)2024 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-39066335

RESUMO

The effects of immunodeficiency associated with chronic HIV infection on COVID-19 disease and viral persistence have not been directly addressed in a controlled setting. In this pilot study, we exposed two pigtail macaques (PTMs) chronically infected with SIVmac239, exhibiting from very low to no CD4 T cells across all compartments, to SARS-CoV-2. We monitored the disease progression, viral replication, and evolution, and compared these outcomes with SIV-naïve PTMs infected with SARS-CoV-2. No overt signs of COVID-19 disease were observed in either animal, and the SARS-CoV-2 viral kinetics and evolution in the SIVmac239 PTMs were indistinguishable from those in the SIV-naïve PTMs in all sampled mucosal sites. However, the single-cell RNA sequencing of bronchoalveolar lavage cells revealed an infiltration of functionally inert monocytes after SARS-CoV-2 infection. Critically, neither of the SIV-infected PTMs mounted detectable anti-SARS-CoV-2 T-cell responses nor anti-SARS-CoV-2 binding or neutralizing antibodies. Thus, HIV-induced immunodeficiency alone may not be sufficient to drive the emergence of novel viral variants but may remove the ability of infected individuals to mount adaptive immune responses against SARS-CoV-2.


Assuntos
COVID-19 , Coinfecção , Modelos Animais de Doenças , SARS-CoV-2 , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia , Animais , Vírus da Imunodeficiência Símia/imunologia , COVID-19/imunologia , COVID-19/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , SARS-CoV-2/imunologia , Coinfecção/imunologia , Coinfecção/virologia , Replicação Viral , Macaca nemestrina , Projetos Piloto , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/sangue , Carga Viral , Linfócitos T CD4-Positivos/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/sangue
18.
Anim Reprod Sci ; : 107537, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38918086

RESUMO

Climate change has been linked to increasing temperatures and weather extremes. Certain regions around the world become more susceptible to environmental hazards that limit pig production and reproductive fertility. Environmental measures that link to pig fertility are needed to assess change, risk and develop solutions. Sub-populations of pigs display lower fertility in summer and are susceptible to heat stress. In the context of a warming climate, elevated temperatures and number of heat stress days increase body temperature and change the physiology, behavior, feed intake, and stress response of the pig. These changes could alter follicle development, oocyte quality, estrus expression, conception and litter size. In boars, sperm quality and production are reduced in response to summer heat stress. Nevertheless, while temperature increases have occurred over the years in some warmer locations, other regions have not shown those changes. Perhaps this involves the measures used for heat stress assessment or that climate is buffered in more temperate areas. Reductions in pig fertility are not always evident, and depend upon climate, year, genotype and management. This could also involve selection, as females more susceptible to heat stress and fertility failure, are subsequently culled. In the years from 1999 to 2020 when increases in global temperature from baseline occurred, measures of female fertility improved for farrowing rate and litter size. Progressive reduction in fertility may not be apparent in all geo-locations, but as temperatures increases become more widespread, these changes are likely to become more obvious and detectable.

19.
Eur J Med Chem ; 275: 116537, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-38875806

RESUMO

Diphyllin is a naturally occurring lignan comprised of an aryl naphthalene lactone scaffold that demonstrates beneficial biological activities in disease models of cancer, obesity, and viral infection. A target of diphyllin and naturally occurring derivatives is the vacuolar ATPase (V-ATPase) complex. Although diphyllin-related natural products are active with in vitro models for viral entry, the potencies and unknown pharmacokinetic properties limit well-designed in vivo evaluations. Previous studies demonstrated that diphyllin derivatives have the utility of blocking the Ebola virus cell entry pathway. However, diphyllin shows limited potency and poor oral bioavailability in mice. An avenue to improve the potency was used in a new library of synthetic derivatives of diphyllin. Diphyllin derivatives exploiting ether linkages at the 4-position with one-to-three carbon spacers to an oxygen or nitrogen atom provided compounds with EC50 values ranging from 7 to 600 nM potency and selectivity up to >500 against Ebola virus in infection assays. These relative potencies are reflected in the Ebola virus infection of primary macrophages, a cell type involved in early pathogenesis. A target engagement study reveals that reducing the ATPV0a2 protein expression enhanced the potency of diphyllin derivatives to block EBOV entry, consistent with effects on the endosomal V-ATPase function. Despite the substantial enhancement of antiviral potencies, limitations were identified, including rapid clearance predicted by in vitro microsome stability assays. However, compounds with similar or improved half-lives relative to diphyllin demonstrated improved pharmacokinetic profiles in vivo. Importantly, these derivatives displayed suitable plasma levels using oral administration, establishing the feasibility of in vivo antiviral testing.


Assuntos
Antivirais , ATPases Vacuolares Próton-Translocadoras , ATPases Vacuolares Próton-Translocadoras/antagonistas & inibidores , ATPases Vacuolares Próton-Translocadoras/metabolismo , Animais , Camundongos , Relação Estrutura-Atividade , Antivirais/farmacologia , Antivirais/química , Antivirais/farmacocinética , Antivirais/síntese química , Humanos , Estrutura Molecular , Ebolavirus/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Relação Dose-Resposta a Droga , Lignanas/farmacologia , Lignanas/química , Naftalenos/farmacologia , Naftalenos/química , Naftalenos/farmacocinética , Naftalenos/síntese química , Internalização do Vírus/efeitos dos fármacos
20.
Acta Physiol (Oxf) ; 240(8): e14185, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38860650

RESUMO

AIM: Alzheimer's disease (AD) is the most common form of dementia. However, while 150+ animal models of AD exist, drug translation from preclinical models to humans for treatment usually fails. One factor contributing to low translation is likely the absence of neurodegenerative models that also encompass the multi-morbidities of human aging. We previously demonstrated that, in comparison to the PigmEnTed (PET) guinea pig strain which models "typical" brain aging, the Hartley strain develops hallmarks of AD like aging humans. Hartleys also exhibit age-related impairments in cartilage and skeletal muscle. Impaired mitochondrial respiration is one driver of both cellular aging and AD. In humans with cognitive decline, diminished skeletal muscle and brain respiratory control occurs in parallel. We previously reported age-related declines in skeletal muscle mitochondrial respiration in Hartleys. It is unknown if there is concomitant mitochondrial dysfunction in the brain. METHODS: Therefore, we assessed hippocampal mitochondrial respiration in 5- and 12-month Hartley and PET guinea pigs using high-resolution respirometry. RESULTS: At 12 months, PETs had higher complex I supported mitochondrial respiration paralleling their increase in body mass compared to 5 months PETs. Hartleys were also heavier at 12 months compared to 5 months but did not have higher complex I respiration. Compared to 5 months Hartleys, 12 months Hartleys had lower complex I mitochondrial efficiency and compensatory increases in mitochondrial proteins collectively suggesting mitochondrial dysfunction with age. CONCLUSIONS: Therefore, Hartleys might be a relevant model to test promising therapies targeting mitochondria to slow brain aging and AD progression.


Assuntos
Envelhecimento , Hipocampo , Mitocôndrias , Animais , Cobaias , Mitocôndrias/metabolismo , Envelhecimento/metabolismo , Hipocampo/metabolismo , Masculino , Respiração Celular/fisiologia , Doença de Alzheimer/metabolismo , Modelos Animais de Doenças
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA