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2.
J Occup Environ Hyg ; : 1-12, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38958555

RESUMO

Direct-on-Filter (DoF) analysis of respirable crystalline silica (RCS) by Fourier Transform Infrared (FTIR) spectroscopy is a useful tool for assessing exposure risks. With the RCS exposure limits becoming lower, it is important to characterize and reduce measurement uncertainties. This study systematically evaluated two filter types (i.e., polyvinyl chloride [PVC] and polytetrafluoroethylene [PTFE]) for RCS measurements by DoF FTIR spectroscopy, including the filter-to-filter and day-to-day variability of blank filter FTIR reference spectra, particle deposition patterns, filtration efficiencies, and pressure drops. For PVC filters sampled at a flow rate of 2.5 L/min for 8 h, the RCS limit of detection (LOD) was 7.4 µg/m3 when a designated laboratory reference filter was used to correct the absorption by the filter media. When the spectrum of the pre-sample filter (blank filter before dust sampling) was used for correction, the LOD could be up to 5.9 µg/m3. The PVC absorption increased linearly with reference filter mass, providing a means to correct the absorption differences between the pre-sample and reference filters. For PTFE, the LODs were 12 and 1.2 µg/m3 when a designated laboratory blank or the pre-sample filter spectrum was used for blank correction, respectively, indicating that using the pre-sample blank spectrum will reduce RCS quantification uncertainty. Both filter types exhibited a consistent radially symmetric deposition pattern when particles were collected using 3-piece cassettes, indicating that RCS can be quantified from a single measurement at the filter center. The most penetrating aerodynamic diameters were around 0.1 µm with filtration efficiencies ≥ 98.8% across the measured particle size range with low-pressure drops (0.2-0.3 kPa) at a flow rate of 2.5 L/min. This study concludes that either the PVC or the PTFE filters are suitable for RCS analysis by DoF FTIR, but proper methods are needed to account for the variability of blank absorption among different filters.

3.
World J Orthop ; 15(6): 585-592, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38947256

RESUMO

BACKGROUND: Cheilectomy of the 1st metatarsophalangeal joint (MTPJ) is one of the most common procedures for the management of hallux rigidus. However, there is no consensus regarding outcomes following minimally invasive dorsal cheilectomy (MIDC) for the management of hallux rigidus. AIM: To evaluate outcomes following MIDC for the management of hallux rigidus. METHODS: During November 2023, the PubMed, EMBASE and Cochrane Library databases were systematically reviewed to identify clinical studies examining outcomes following MIDC for the management of hallux rigidus. RESULTS: Six studies were included. In total, 348 patients (370 feet) underwent MIDC for hallux rigidus at a weighted mean follow-up of 37.9 ± 16.5 months. The distribution of patients by Coughlin and Shurna's classification was recorded in 4 studies as follows: I (58 patients, 27.1%), II (112 patients, 52.3%), III (44 patients, 20.6%). Three studies performed an additional 1st MTPJ arthroscopy and debridement following MIDC. Retained intra-articular bone debris was observed in 100% of patients in 1 study. The weighted mean American orthopedic foot and ankle society score improved from a preoperative score of 68.9 ± 3.2 to a postoperative score of 87.1. The complication rate was 8.4%, the most common of which was persistent joint pain and stiffness. Thirty-two failures (8.7%) were observed. Thirty-three secondary procedures (8.9%) were performed at a weighted mean time of 8.6 ± 3.2 months following the index procedure. CONCLUSION: This systematic review demonstrated improvements in subjective clinical outcomes together with a moderate complication rate following MIDC for the management of hallux rigidus at short-term follow-up. A moderate re-operation rate at short-term follow-up was recorded. The marked heterogeneity between included studies and paucity of high quality comparative studies limits the generation of any robust conclusions.

4.
Front Plant Sci ; 15: 1420068, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38957597

RESUMO

Some volatile organic compounds (VOCs) produced by microorganisms have the ability to inhibit the growth and development of plant pathogens, induce the activation of plant defenses, and promote plant growth. Among them, 6-pentyl-alpha-pyrone (6-PP), a ketone produced by Trichoderma fungi, has emerged as a focal point of interest. 6-PP has been isolated and characterized from thirteen Trichoderma species and is the main VOC produced, often accounting for >50% of the total VOCs emitted. This review examines abiotic and biotic interactions regulating the production of 6-PP by Trichoderma, and the known effects of 6-PP on plant pathogens through direct and indirect mechanisms including induced systemic resistance. While there are many reports of 6-PP activity against plant pathogens, the vast majority have been from laboratory studies involving only 6-PP and the pathogen, rather than glasshouse or field studies including a host plant in the system. Biopesticides based on 6-PP may well provide an eco-friendly, sustainable management tool for future agricultural production. However, before this can happen, challenges including demonstrating disease control efficacy in the field, developing efficient delivery systems, and determining cost-effective application rates must be overcome before 6-PP's potential for pathogen control can be turned into reality.

5.
Artigo em Inglês | MEDLINE | ID: mdl-38960802

RESUMO

This article reviews the recent and relevant literature to the field of aortic surgery. Specific areas highlighted include outcomes of Stanford type A dissection, management of acute aortic syndromes, management of aortic aneurysms, and traumatic aortic injury. Although the focus was on articles from 2023, literature from prior years also was included, given that this article is the first of a series. Notably, the pertinent sections from the 2022 American College of Cardiology/American Heart Association Guidelines for the Diagnosis and Management Aortic Disease are discussed.

6.
Health Commun ; : 1-14, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38961665

RESUMO

Cultural targeting and tailoring are different, yet they remain intertwined in the literature inhibiting theory development and limiting the possibility of determining their effects. This preregistered systematic literature review describes these constructs and provides a framework for cultural tailoring with evidence from a review of 63 studies, published from 2010 to 2020, to characterize the processes, elements, and theories used in the existing literature. The results show that 86% of studies self-defined as cultural tailoring, but coding revealed relatively few tailoring studies (25%) with 31% including both tailoring and targeting elements. Most studies used outreach and consultation as processes for tailoring or targeting with participatory approaches used in a fifth of the studies. Surface-level features of message content were commonly used to tailor or target with deep-cultural-values found in only a quarter of the studies. We argue from theories of communication accommodation and persuasion that cultural tailoring or targeting may provide gains in attention, recall, or source evaluation.

7.
Redox Biol ; 75: 103261, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38963974

RESUMO

Squamous cell carcinomas (SCCs), including lung, head & neck, bladder, and skin SCCs often display constitutive activation of the KEAP1-NRF2 pathway. Constitutive activation is achieved through multiple mechanisms, including activating mutations in NFE2L2 (NRF2). To determine the functional consequences of Nrf2 activation on skin SCC development, we assessed the effects of mutant Nrf2E79Q expression, one of the most common activating mutations in human SCCs, on tumor promotion and progression in the mouse skin multistage carcinogenesis model using a DMBA-initiation/TPA-promotion protocol where the Hras A->T mutation (Q61L) is the canonical driver mutation. Nrf2E79Q expression was temporally and conditionally activated in the epidermis at two stages of tumor development: 1) after DMBA initiation in the epidermis but before cutaneous tumor development and 2) in pre-existing DMBA-initiated/TPA-promoted squamous papillomas. Expression of Nrf2E79Q in the epidermis after DMBA initiation but before tumor occurrence inhibited the development/promotion of 70% of squamous papillomas. However, the remaining papillomas often displayed non-canonical Hras and Kras mutations and enhanced progression to SCCs compared to control mice expressing wildtype Nrf2. Nrf2E79Q expression in pre-existing tumors caused rapid regression of 60% of papillomas. The remaining papillomas displayed the expected canonical Hras A->T mutation (Q61L) and enhanced progression to SCCs. These results demonstrate that mutant Nrf2E79Q enhances the promotion and progression of a subset of skin tumors and alters the frequency and diversity of oncogenic Ras mutations when expressed early after initiation.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38969075

RESUMO

BACKGROUND & AIMS: Desmoid tumours (DT) are an important cause of morbidity and mortality in patients with familial adenomatous polyposis (FAP). DT development might be related to the type and approach of colectomy. We aimed to compare DT development after colectomy with ileorectal anastomosis (IRA) and proctocolectomy with ileal pouch-anal anastomosis (IPAA). METHODS: We performed an international historical cohort study in FAP patients who underwent IRA or IPAA between 1961 and 2020. The primary outcome was the incidence of abdominal DT (either mesenteric, retroperitoneal or abdominal wall). Patients with a DT diagnosis before or at colectomy were excluded. Time to DT was considered censored at an eventual secondary proctectomy after IRA. We used multivariable Cox regression modelling to adjust for potential confounders. RESULTS: We analysed data from 852 patients: 514 after IRA and 338 after IPAA (median follow-up 21 and 16 years, respectively). DTs were diagnosed in 64 IRA patients (12%) and 66 IPAA patients (20%). The cumulative DT incidence at 5 and 10 years was 7.5% and 9.3% after open IRA and 4.7% and 10.9% after laparoscopic IRA. These estimates were 13.6% and 15.4% after open IPAA and 8.4% and 10.0% after laparoscopic IPAA. The post-operative risk was significantly higher after IPAA (p < 0.01) in multivariable analysis, while approach did not significantly influence the risk. CONCLUSIONS: The risk of developing an abdominal DT was found to be significantly higher after IPAA than after IRA. Postoperative DT risk should be taken into account when choosing between IRA and IPAA in FAP.

9.
J Nerv Ment Dis ; 212(7): 392-397, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949659

RESUMO

ABSTRACT: The study was set out to establish the potential for psychotherapy to effect improvements in patients with narcissistic personality disorder (NPD). Eight patients with NPD who improved in treatment were identified. Consensus clinician/investigator diagnostic scores from before and after the psychotherapies were retroactively established on the Diagnostic Interview for Narcissism (DIN) and the Diagnostic Statistic Manual for Psychiatric Disorders, 5th Edition (DSM-5) Personality Disorder Section II criteria. Psychosocial functioning (work or school, romantic relationships) before and after the psychotherapies was retroactively evaluated as well. At the completion of the therapies after 2.5 to 5 years, all patients had improved, no longer met DIN or DSM-5 criteria for NPD, and showed better psychosocial functioning. Symptomatic improvements were associated with large effect sizes. In conclusion, changes in NPD can occur in treatment after 2.5 to 5 years. Future research should identify patient characteristics, interventions, and common processes in such improved cases that could help with development of treatments.


Assuntos
Transtornos da Personalidade , Humanos , Transtornos da Personalidade/terapia , Transtornos da Personalidade/diagnóstico , Adulto , Feminino , Masculino , Pessoa de Meia-Idade , Psicoterapia/métodos , Resultado do Tratamento , Narcisismo , Adulto Jovem , Manual Diagnóstico e Estatístico de Transtornos Mentais , Funcionamento Psicossocial , Transtorno da Personalidade Narcisística
10.
J Biomed Mater Res A ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984402

RESUMO

Injectable in situ-forming scaffolds that induce both angiogenesis and osteogenesis have been proven to be promising for bone healing applications. Here, we report the synthesis of an injectable hydrogel containing cobalt-doped bioactive glass (BG)-loaded microspheres. Silk fibroin (SF)/gelatin microspheres containing BG particles were fabricated through microfluidics. The microspheres were mixed in an injectable alginate solution, which formed an in situ hydrogel by adding CaCl2. The hydrogel was evaluated for its physicochemical properties, in vitro interactions with osteoblast-like and endothelial cells, and bone healing potential in a rat model of calvarial defect. The microspheres were well-dispersed in the hydrogel and formed pores of >100 µm. The hydrogel displayed shear-thinning behavior and modulated the cobalt release so that the optimal cobalt concentration for angiogenic stimulation, cell proliferation, and deposition of mineralized matrix was only achieved by the scaffold that contained BG doped with 5% wt/wt cobalt (A-S-G5Co). In the scaffold containing higher cobalt content, a reduced biomimetic mineralization on the surface was observed. The gene expression study indicated an upregulation of the osteogenic genes of COL1A1, ALPL, OCN, and RUNX2 and angiogenic genes of HIF1A and VEGF at different time points in the cells cultured with the A-S-G5Co. Finally, the in vivo study demonstrated that A-S-G5Co significantly promoted both angiogenesis and osteogenesis and improved bone healing after 12 weeks of follow-up. These results show that incorporation of SF/gelatin microspheres containing cobalt-doped BG in an injectable in situ-forming scaffold can effectively enhance its bone healing potential through promotion of angiogenesis and osteogenesis.

11.
Mol Ecol ; : e17463, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984610

RESUMO

Here we investigate the evolutionary dynamics of five enzyme superfamilies (CYPs, GSTs, UGTs, CCEs and ABCs) involved in detoxification in Helicoverpa armigera. The reference assembly for an African isolate of the major lineages, H. a. armigera, has 373 genes in the five superfamilies. Most of its CYPs, GSTs, UGTs and CCEs and a few of its ABCs occur in blocks and most of the clustered genes are in subfamilies specifically implicated in detoxification. Most of the genes have orthologues in the reference genome for the Oceania lineage, H. a. conferta. However, clustered orthologues and subfamilies specifically implicated in detoxification show greater sequence divergence and less constraint on non-synonymous differences between the two assemblies than do other members of the five superfamilies. Two duplicated CYPs, which were found in the H. a. armigera but not H. a. conferta reference genome, were also missing in 16 Chinese populations spanning two different lineages of H. a. armigera. The enzyme produced by one of these duplicates has higher activity against esfenvalerate than a previously described chimeric CYP mutant conferring pyrethroid resistance. Various transposable elements were found in the introns of most detoxification genes, generating diverse gene structures. Extensive resequencing data for the Chinese H. a. armigera and H. a. conferta lineages also revealed complex copy number polymorphisms in 17 CCE001s in a cluster also implicated in pyrethroid metabolism, with substantial haplotype differences between all three lineages. Our results suggest that cotton bollworm has a versatile complement of detoxification genes which are evolving in diverse ways across its range.

12.
Cureus ; 16(6): e62044, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38989354

RESUMO

Extracellular matrix cartilage allograft (EMCA) is a novel biological strategy utilized to augment the repair of osteochondral lesions of the talus (OLTs). However, there is no consensus on the precise role and outcomes following its use in the treatment of OLTs. The purpose of this systematic review was to evaluate the clinical and radiological outcomes following the use of EMCA for the treatment of OLT. During July 2023, the PubMed, Embase, and Cochrane Library databases were systematically reviewed to identify clinical studies examining outcomes following EMCA for the management of OLTs. In total, 162 patients (162 ankles) across five studies received EMCA as part of their surgical procedure at a weighted mean follow-up time of 23.8±4.2 months. Across all five studies, there were improvements in subjective clinical outcomes following the use of EMCA, regardless of the clinical scoring tool utilized. Two studies demonstrated superior postoperative magnetic resonance observation of cartilage repair tissue (MOCART) scores in the EMCA cohort compared to the bone marrow stimulation (BMS) cohort alone. In the EMCA-BMS cohort, there were seven complications (9%) and three failures (4.1%). In the autologous osteochondral transplantation (AOT) cohort, there were 10 complications (38.5%), zero failures, and six secondary surgical procedures (23.1%). In the EMCA alone cohort, there were zero complications and three failures (4.3%), all of which underwent an unspecified revision procedure. This current systematic review demonstrated improvements in both clinical and radiological outcomes following the use of EMCA for the treatment of OLTs. Further prospective comparative studies with longer follow-up times are warranted to determine the precise role of EMCA in the management of OLT.

13.
J Surg Orthop Adv ; 33(2): 108-111, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38995068

RESUMO

The diagnosis of septic arthritis requires a reliance on ancillary tests, including synovial fluid white blood cell count (jWBC), percentage of polymorphonuclear leukocytes (%PMN), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). This study evaluated these tests to determine their diagnostic utility in suspected septic arthritis. A retrospective chart review was performed on patients admitted to an urban hospital who underwent arthrocentesis. The authors evaluated the jWBC, %PMN, ESR, and CRP with receiver operating characteristic (ROC) curve analyses. Two hundred sixty-five patients met inclusion criteria. Sixty-three had a culture-positive aspirate. ROC curve analysis resulted in an area under the curve (AUC) of 0.80 for jWBC with cutoff point of 22,563 cells/mm3 and an AUC of 0.71 for %PMN with cutoff point of 90.5%. CRP and ESR had AUC values of 0.62 and 0.61, respectively. The culture-positive cohort had higher elevations in all assessed diagnostic tests. However, AUC data for ESR and CRP showed little diagnostic utility. Additionally, sensitivities and specificities of jWBC and %PMN were too low. Associated cutoff points would result in excessive unnecessary operative intervention. Further studies should incorporate synovial fluid biomarkers into the workup of a suspected septic joint. (Journal of Surgical Orthopaedic Advances 33(2):108-111, 2024).


Assuntos
Artrite Infecciosa , Sedimentação Sanguínea , Proteína C-Reativa , Líquido Sinovial , Humanos , Artrite Infecciosa/diagnóstico , Estudos Retrospectivos , Masculino , Feminino , Pessoa de Meia-Idade , Proteína C-Reativa/análise , Contagem de Leucócitos , Idoso , Curva ROC , Adulto , Artrocentese , Neutrófilos , Sensibilidade e Especificidade , Biomarcadores/análise , Idoso de 80 Anos ou mais
14.
J Med Chem ; 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38995264

RESUMO

This Perspective is a continuation of our analysis of U.S. FDA-approved small-molecule drugs (1938-2012) containing nitrogen heterocycles. In this study we report drug structure and property analyses of 321 unique new small-molecule drugs approved from January 2013 to December 2023 as well as information about frequency of important heteroatoms such as sulfur and fluorine and key small nitrogen substituents (CN and NO2). The most notable change is an incredible increase in drugs containing at least one nitrogen heterocycle─82%, compared to 59% from preceding decades─as well as a significant increase in the number of nitrogen heterocycles per drug. Pyridine has claimed the #1 high-frequency nitrogen heterocycle occurrence spot from piperidine (#2), with pyrimidine (#5), pyrazole (#6), and morpholine (#9) being the big top 10 climbers. Also notable is high number of fused nitrogen heterocycles, apparently driven largely by newly approved cancer drugs.

16.
Glob Chang Biol ; 30(7): e17399, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39007251

RESUMO

The ever-increasing and expanding globalisation of trade and transport underpins the escalating global problem of biological invasions. Developing biosecurity infrastructures is crucial to anticipate and prevent the transport and introduction of invasive alien species. Still, robust and defensible forecasts of potential invaders are rare, especially for species without known invasion history. Here, we aim to support decision-making by developing a quantitative invasion risk assessment tool based on invasion syndromes (i.e., generalising typical attributes of invasive alien species). We implemented a workflow based on 'Multiple Imputation with Chain Equation' to estimate invasion syndromes from imputed datasets of species' life-history and ecological traits and macroecological patterns. Importantly, our models disentangle the factors explaining (i) transport and introduction and (ii) establishment. We showcase our tool by modelling the invasion syndromes of 466 amphibians and reptile species with invasion history. Then, we project these models to amphibians and reptiles worldwide (16,236 species [c.76% global coverage]) to identify species with a risk of being unintentionally transported and introduced, and risk of establishing alien populations. Our invasion syndrome models showed high predictive accuracy with a good balance between specificity and generality. Unintentionally transported and introduced species tend to be common and thrive well in human-disturbed habitats. In contrast, those with established alien populations tend to be large-sized, are habitat generalists, thrive well in human-disturbed habitats, and have large native geographic ranges. We forecast that 160 amphibians and reptiles without known invasion history could be unintentionally transported and introduced in the future. Among them, 57 species have a high risk of establishing alien populations. Our reliable, reproducible, transferable, statistically robust and scientifically defensible quantitative invasion risk assessment tool is a significant new addition to the suite of decision-support tools needed for developing a future-proof preventative biosecurity globally.


Assuntos
Anfíbios , Previsões , Espécies Introduzidas , Répteis , Animais , Répteis/fisiologia , Anfíbios/fisiologia , Medição de Risco/métodos , Modelos Teóricos , Modelos Biológicos
17.
ESC Heart Fail ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39013806

RESUMO

Patients with acutely decompensated heart failure (ADHF) are usually admitted to hospital for management. There is growing interest in delivering intravenous (IV) diuretic therapy at home, in the community or at hospital day-care units; the safety and effectiveness of outpatient-based management (OPM) for ADHF has not been established. We conducted a systematic literature review and meta-analysis to investigate the short-term safety and effectiveness of OPM compared with inpatient management (IPM) of ADHF. Pre-specified endpoints were 30 day mortality and 30 day hospitalization. The meta-analysis was conducted using RevMan 5.4 software. Twenty-nine studies of OPM were identified, including 7683 patients. Only five studies directly compared OPM (n = 1303) with IPM (n = 2047), including three observational studies, and two randomized controlled trials (RCTs). The other 24 studies only stated OPM outcomes. For the five studies comparing IPM versus OPM, patients were generally aged >75 years and of similar age for each strategy, with a similar proportion of men (56%). In a study-level, aggregate analysis, 30 day all-cause mortality was 9.3% (121/1303) for OPM, compared with 15.6% (320/2047) for IPM [OR 0.29 (95% CI 0.09, 0.93) P = 0.04]. Four studies reported 30 day all-cause hospitalization; 22.0% for IPM versus 16.8% for OPM [OR 0.73 (95% CI 0.61, 0.89), P = 0.001]. In the two RCTs, we found no difference in 30 day mortality or hospitalization. In observational studies, OPM of ADHF is associated with lower 30 day hospitalization and lower 30 day mortality; such differences were not observed in two small, single-centre RCTs. A substantial, multicentre RCT is required to confirm the safety and effectiveness of OPM for ADHF.

19.
Palliat Med Rep ; 5(1): 238-246, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39044760

RESUMO

Background: Nearly half of more than 1.7 million older Americans who receive hospice care each year have a primary or comorbid diagnosis of dementia. Pain is often undertreated in this patient population owing to myriad factors, including unmet informational needs among family caregivers. Objective: We sought to inform the adaptation of a pain education intervention for hospice family caregivers to the context of dementia by eliciting feedback on the educational content covered in adapted intervention materials. Design: We conducted a multimethod, formative research study to inform the adaptation of an existing, evidence-based intervention. Setting/Subjects: The study included a purposively recruited sample (n = 33) of hospice professionals (n = 18) and family caregivers (n = 15) from across the United States. Measurements: Participants quantitatively rated the importance of each of the eight pain concerns presented in the adapted intervention materials (1 = not important to 3 = very important) and provided qualitative feedback via Zoom interview on the acceptability, clinical accuracy, and potential benefits of the adapted content. We analyzed quantitative data via descriptive statistics and qualitative data via content analysis. Results: Participants rated the adapted educational content as highly important (rangemean = 2.56-3.00), particularly regarding concerns about caregivers' pain assessment, communicating with the hospice team about pain, and addressing misinformation regarding pain medication outcomes. Participants also provided suggestions to strengthen specific educational messages to improve comprehension and uptake. Conclusions: Findings support the continued development and testing of the adapted intervention.

20.
J Exp Biol ; 227(14)2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39045755

RESUMO

Many bones experience bending, placing one side in net compression and the other in net tension. Because bone mechanical properties are relatively reduced in tension compared with compression, adaptations are needed to reduce fracture risk. Several toughening mechanisms exist in bone, yet little is known of the influences of secondary osteon collagen/lamellar 'morphotypes' and potential interplay with intermolecular collagen cross-links (CCLs) in prevalent/predominant tension- and compression-loaded regions. Paired third metacarpals (MC3s) from 10 adult horses were prepared for mechanical testing. From one MC3/pair, 5 mm cubes were tested in compression at several mid-shaft locations. From contralateral bones, dumbbell-shaped specimens were tested in tension. Hence, habitual/natural tension- and compression-loaded regions were tested in both modes. Data included: elastic modulus, yield and ultimate strength, and energy absorption (toughness). Fragments of tested specimens were examined for predominant collagen fiber orientation (CFO; representing osteonal and non-osteonal bone), osteon morphotype score (MTS, representing osteonal CFO), mineralization, porosity and other histological characteristics. As a consequence of insufficient material from tension-tested specimens, CCLs were only examined in compression-tested specimens (HP, hydroxylysylpyridinoline; LP, lysylpyridinoline; PE, pentosidine). Among CCLs, only LP and HP/LP correlated significantly with mechanical parameters: LP with energy absorption, HP/LP with elastic modulus (both r=0.4). HP/LP showed a trend with energy absorption (r=-0.3, P=0.08). HP/LP more strongly correlated with osteon density and mineralization than CFO or MTS. Predominant CFO more strongly correlated with energy absorption than MTS in both testing modes. In general, CFO was found to be relatively prominent in affecting regional toughness in these equine MC3s in compression and tension.


Assuntos
Colágeno , Ósteon , Ossos Metacarpais , Animais , Cavalos/fisiologia , Colágeno/química , Colágeno/metabolismo , Ossos Metacarpais/fisiologia , Ossos Metacarpais/anatomia & histologia , Ossos Metacarpais/química , Ósteon/fisiologia , Fenômenos Biomecânicos , Força Compressiva , Estresse Mecânico , Módulo de Elasticidade
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