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BACKGROUND: Homologous recombination repair deficiency (HRD) is a frequent feature of high-grade serous ovarian, fallopian tube and peritoneal carcinoma (HGSC) and is associated with sensitivity to PARP inhibitor (PARPi) therapy. HRD testing provides an opportunity to optimise PARPi use in HGSC but methodologies are diverse and clinical application remains controversial. MATERIALS AND METHODS: To define best practice for HRD testing in HGSC the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project that incorporated a systematic review approach. The main aims were to (i) define the term 'HRD test'; (ii) provide an overview of the biological rationale and the level of evidence supporting currently available HRD tests; (iii) provide recommendations on the clinical utility of HRD tests in clinical management of HGSC. RESULTS: A broad range of repair genes, genomic scars, mutational signatures and functional assays are associated with a history of HRD. Currently, the clinical validity of HRD tests in ovarian cancer is best assessed, not in terms of biological HRD status per se, but in terms of PARPi benefit. Clinical trials evidence supports the use of BRCA mutation testing and two commercially available assays that also incorporate genomic instability for identifying subgroups of HGSCs that derive different magnitudes of benefit from PARPi therapy, albeit with some variation by clinical scenario. These tests can be used to inform treatment selection and scheduling but their use is limited by a failure to consistently identify a subgroup of patients who derive no benefit from PARPis in most studies. Existing tests lack negative predictive value and inadequately address the complex and dynamic nature of the HRD phenotype. CONCLUSIONS: Currently available HRD tests are useful for predicting likely magnitude of benefit from PARPis but better biomarkers are urgently needed to better identify current homologous recombination proficiency status and stratify HGSC management.
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Neoplasias Ováricas , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Biomarcadores , Carcinoma Epitelial de Ovario , Femenino , Recombinación Homóloga , Humanos , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/genética , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéuticoRESUMEN
The European Society for Medical Oncology (ESMO) Translational Research and Precision Medicine Working Group identified that there is currently uncertainty within the oncology community surrounding the different methods for HRD testing in HGSC. To address this, a collaborative project was launched with a number of clinicians and scientists with expertise in the fields of PARPi clinical trials, cancer genomics and DNA repair. The group defined three main aims for the project: (i) Define the term 'HRD test' and recommend how an HRD test's clinical validity is currently best assessed in the context of HGSC, (ii) provide an overview of the biological rationale and the level of evidence supporting currently available HRD tests, and (iii) provide recommendations on the clinical utility of HRD tests in clinical management of HGSC.
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Humanos , Femenino , Biomarcadores , Neoplasias de los Genitales Femeninos/diagnóstico , Mutación de Línea Germinal/genética , Recombinación Homóloga/genética , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéuticoRESUMEN
OBJECTIVE: Following destabilization of the medial meniscus (DMM), mice develop experimental osteoarthritis (OA) and associated pain behaviors that are dependent on the stage of disease. We aimed to describe changes in gene expression in knee-innervating dorsal root ganglia (DRG) after surgery, in order to identify molecular pathways associated with three pre-defined pain phenotypes: "post-surgical pain", "early-stage OA pain", and "persistent OA pain". DESIGN: We performed DMM or sham surgery in 10-week old male C57BL/6 mice and harvested L3-L5 DRG 4, 8, and 16 weeks after surgery or from age-matched naïve mice (n = 3/group). RNA was extracted and an Affymetrix Mouse Transcriptome Array 1.0 was performed. Three pain phenotypes were defined: "post-surgical pain" (sham and DMM 4-week vs 14-week old naïve), "early OA pain" (DMM 4-week vs sham 4-week), and "persistent OA pain" (DMM 8- and 16-week vs naïve and sham 8- and 16-week). 'Top hit' genes were defined as P < 0.001. Pathway analysis (Ingenuity Pathway Analysis) was conducted using differentially expressed genes defined as P < 0.05. In addition, we performed qPCR for Ngf and immunohistochemistry for F4/80+ macrophages in the DRG. RESULTS: For each phenotype, top hit genes identified a small number of differentially expressed genes, some of which have been previously associated with pain (7/67 for "post-surgical pain"; 2/14 for "early OA pain"; 8/37 for "persistent OA pain"). Overlap between groups was limited, with 8 genes differentially regulated (P < 0.05) in all three phenotypes. Pathway analysis showed that in the persistent OA pain phase many of the functions of differentially regulated genes are related to immune cell recruitment and activation. Genes previously linked to OA pain (CX3CL1, CCL2, TLR1, and NGF) were upregulated in this phenotype and contributed to activation of the neuroinflammation canonical pathway. In separate sets of mice, we confirmed that Ngf was elevated in the DRG 8 weeks after DMM (P = 0.03), and numbers of F4/80+ macrophages were increased 16 weeks after DMM (P = 0.002 vs Sham). CONCLUSION: These transcriptomics findings support the idea that distinct molecular pathways discriminate early from persistent OA pain. Pathway analysis suggests neuroimmune interactions in the DRG contribute to initiation and maintenance of pain in OA.
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Artralgia/genética , Ganglios Espinales/metabolismo , Expresión Génica , Inmunidad Innata/genética , Osteoartritis de la Rodilla/genética , Dolor Postoperatorio/genética , Animales , Artralgia/inmunología , Artritis Experimental/genética , Artritis Experimental/inmunología , Progresión de la Enfermedad , Perfilación de la Expresión Génica , Inmunidad Innata/inmunología , Masculino , Meniscos Tibiales/cirugía , Ratones , Análisis por Micromatrices , Neuroinmunomodulación/genética , Neuroinmunomodulación/inmunología , Osteoartritis/genética , Osteoartritis/inmunología , Osteoartritis de la Rodilla/inmunología , Dolor Postoperatorio/inmunología , Fenotipo , ARN Mensajero/metabolismoRESUMEN
In this narrative review, we discuss the emerging role of innate immunity in osteoarthritis (OA) joint pain. First, we give a brief description of the pain pathway in the context of OA. Then we consider how neuro-immune signaling pathways may promote OA pain. First, activation of neuronal Pattern Recognition Receptors by mediators released in a damaged joint can result in direct excitation of nociceptors, as well as in production of chemokines and cytokines. Secondly, indirect neuro-immune signaling may occur when innate immune cells produce algogenic factors, including chemokines and cytokines, that act on the pain pathway. Neuro-immune crosstalk occurs at different levels of the pathway, starting in the joint but also in the innervating dorsal root ganglia and in the dorsal horn. Synovitis is characterized by recruitment of immune cells, including macrophages, mast cells, and CD4+ lymphocytes, which may contribute to nociceptor sensitization and OA pain through production of algogenic factors that amplify the activation of sensory neurons. We discuss examples where this scenario has been suggested by findings in human OA and in animal models. Overall, increasing evidence suggests that innate immune pathways play an initiating as well as facilitating role in pain, but information on how these pathways operate in OA remains limited. Since these innate pathways are eminently targetable, future studies in this area may provide fruitful leads towards a better management of symptomatic OA.
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Artralgia/inmunología , Inmunidad Innata/inmunología , Nociceptores/metabolismo , Osteoartritis/inmunología , Sinovitis/inmunología , Animales , Artralgia/metabolismo , Citocinas/inmunología , Citocinas/metabolismo , Ganglios Espinales/inmunología , Ganglios Espinales/metabolismo , Humanos , Neuroinmunomodulación/inmunología , Osteoartritis/metabolismo , Receptores de Reconocimiento de Patrones/metabolismo , Asta Dorsal de la Médula Espinal/inmunología , Asta Dorsal de la Médula Espinal/metabolismo , Sinovitis/metabolismoRESUMEN
OBJECTIVES: To document the nociceptive innervation of the normal and osteoarthritic murine knee. METHODS: Knees were collected from naïve male C57BL/6 NaV1.8-tdTomato reporter mice aged 10, 26, and 52 weeks (n = 5/group). Destabilization of the medial meniscus (DMM) or sham surgeries (n = 5/group) were performed in the right knee of 10-week old male NaV1.8-tdTomato mice, and knees were harvested 16 weeks later. Twenty 20-µm frozen sections from a 400-µm mid-joint region were collected for confocal microscopy. Integrated density of the tdTomato signal was calculated using Image J by two independent observers blinded to the groups. Consecutive sections were stained with hematoxylin & eosin. C57BL/6-Pirt-GCaMP3 mice (n = 5/group) and protein gene product 9.5 (PGP9.5) immunostaining of C57BL/6 wild type (WT) mice (n = 5/group) were used to confirm innervation patterns. RESULTS: In naive 10-week old mice, nociceptive innervation was most dense in bone marrow cavities, lateral synovium and at the insertions of the cruciate ligaments. By age 26 weeks, unoperated knees showed a marked decline in nociceptors in the lateral synovium and cruciate ligament insertions. No further decline was observed by age 1 year. Sixteen weeks after DMM, the medial compartment of OA knees exhibited striking changes in NaV1.8+ innervation, including increased innervation of the medial synovium and meniscus, and nociceptors in subchondral bone channels. All results were confirmed through quantification, also in Pirt-GCaMP3 and PGP9.5-immunostained WT mice. CONCLUSIONS: Nociceptive innervation of the mouse knee markedly declines by age 26 weeks, before onset of spontaneous OA. Late-stage surgically induced OA is associated with striking plasticity of joint afferents in the medial compartment of the knee.
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Articulación de la Rodilla/inervación , Nocicepción/fisiología , Nociceptores/fisiología , Osteoartritis de la Rodilla/fisiopatología , Rango del Movimiento Articular/fisiología , Animales , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BLAsunto(s)
Osteoartritis , Animales , Quimiocinas CC , Modelos Animales de Enfermedad , Ratones , Receptores CCR2RESUMEN
OBJECTIVE: Microgliosis, the activation of microglial cells, is thought to contribute to synaptic transmission in the dorsal horn and thereby promote chronic pain. The primary aim of this study was to document the temporal profile of dorsal horn microgliosis after destabilization of the medial meniscus (DMM) in wild type (WT) and Adamts5 null mice. Since neuronal fractalkine (CX3CL1) contributes to microgliosis, we assessed its release from dorsal root ganglia (DRG) cultures after DMM. DESIGN: DMM or sham surgery was performed in the right knee of 10-week old male WT, CX3CR1-green fluorescent protein (GFP), or Adamts5 null C57BL/6 mice. Hind paw mechanical allodynia was monitored using von Frey fibers. L4 dorsal horn microgliosis was assessed 4, 8 and 16 weeks after surgery, based on the morphology of Iba1-immunoreactive microglia. DRG cells (L3-L5) were cultured and supernatants collected for fractalkine (FKN) ELISA. RESULTS: In WT mice, numbers of activated microglia were increased 8 and 16 weeks, but not 4 weeks, after DMM but not sham surgery. DRG cultures showed increased basal FKN release at 8 and 16 weeks. Adamts5 null mice did not develop mechanical allodynia up to 16 weeks after DMM. Accordingly, DRG cultures from these mice did not exhibit increased FKN release and dorsal horn microgliosis did not occur. CONCLUSION: DMM surgery leads to late stage dorsal horn microgliosis. The temporal correlation with DRG FKN release suggests it may contribute to microgliosis. Reduced microgliosis in Adamts5 null mice, which are protected from joint damage and associated mechanical allodynia after DMM, suggests that microgliosis is associated with joint damage and accompanying persistent pain.
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Quimiocina CX3CL1/metabolismo , Hiperalgesia/metabolismo , Microglía/patología , Osteoartritis de la Rodilla/cirugía , Animales , Biomarcadores/metabolismo , Modelos Animales de Enfermedad , Ganglios Espinales/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microglía/metabolismo , Modelos Anatómicos , Osteoartritis de la Rodilla/metabolismo , Dolor/metabolismo , Dolor/fisiopatología , Distribución Aleatoria , Valores de Referencia , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: The role of inflammation in structural and symptomatic osteoarthritis (OA) remains unclear. One key mediator of inflammation is the chemokine CCL2, primarily responsible for attracting monocytes to sites of injury. We investigated the role of CCL2 and its receptor CCR2 in experimental OA. DESIGN: OA was induced in 10 weeks old male wild type (WT), Ccl2-/- and Ccr2-/- mice, by destabilisation of the medial meniscus (DMM). RNA was extracted from whole joints at 6 h and 7 days post-surgery and examined by reverse transcription polymerase chain reaction (RT-PCR). Gene expression changes between naïve and DMM-operated mice were compared. Chondropathy scores, from mice at 8, 12, 16 and 20 weeks post DMM were calculated using modified Osteoarthritis Research Society International (OARSI) grading systems. Changes in hind paw weight distribution, as a measure of pain, were assessed by Linton incapacitance. RESULTS: Absence of CCL2 strongly suppressed (>90%) selective inflammatory response genes in the joint 6 h post DMM, including arginase 1, prostaglandin synthase 2, nitric oxide synthase 2 and inhibin A. IL6, MMP3 and tissue inhibitor of metalloproteinase 1 were also significantly suppressed. Similar trends were also observed in the absence of CCR2. A lower average chondropathy score was observed in both Ccl2-/- and Ccr2-/- mice at 12, 16 and 20 weeks post DMM compared with WT mice, but this was only statistically significant at 20 weeks in Ccr2-/- mice. Pain-related behaviour in Ccl2-/- and Ccr2-/- mice post DMM was delayed in onset. CONCLUSION: The CCL2/CCR2 axis plays an important role in the development of pain in murine OA, but contributes little to cartilage damage.
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Quimiocina CCL2/metabolismo , Osteoartritis/metabolismo , Dolor/metabolismo , Receptores CCR2/metabolismo , Animales , Modelos Animales de Enfermedad , Expresión Génica , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Osteoartritis/etiología , Osteoartritis/patología , Dolor/etiología , Dolor/patología , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
BACKGROUND: The role of docetaxel chemotherapy in combination with androgen deprivation therapy for metastatic castrate-sensitive prostate cancer is emerging. METHODS: We reviewed the results from the pivotal randomized phase III trials in this area: GETUG15, CHAARTED and STAMPEDE. RESULTS: All three studies demonstrated a benefit in progression-free survival with the use of docetaxel. However, two of the studies demonstrated a clinically meaningful overall survival benefit (CHAARTED and STAMPEDE), whereas the GETUG15 study did not demonstrate a major benefit. CONCLUSIONS: Docetaxel is an important option to consider for men who are fit for chemotherapy with newly diagnosed metastatic prostate cancer commencing androgen deprivation therapy.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/patología , Antagonistas de Andrógenos/administración & dosificación , Antagonistas de Andrógenos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Ensayos Clínicos Fase III como Asunto , Docetaxel , Humanos , Masculino , Metástasis de la Neoplasia , Ensayos Clínicos Controlados Aleatorios como Asunto , Taxoides/administración & dosificación , Resultado del TratamientoRESUMEN
OBJECTIVE: The primary goal of this study was to test the disease-modifying effect of blocking a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5 with a neutralizing monoclonal antibody (mAb) starting 4 weeks after destabilization of the medial meniscus (DMM) in the mouse. We also investigated whether ADAMTS-5 blockade reversed mechanical allodynia and decreased monocyte chemoattractant protein (MCP)-1 production by dorsal root ganglia (DRG) cells. METHODS: Ten-week old male C57BL/6 mice underwent DMM surgery and were either left untreated or treated with anti-ADAMTS-5 mAb or IgG2c isotype control mAb starting 4 weeks after surgery. Knees were collected for histopathology 4 or 12 weeks later. Mechanical allodynia was monitored biweekly in the ipsilateral hind paw through 16 weeks. DRG were collected and cultured 8 weeks after DMM for analysis of MCP-1 production. RESULTS: By 4 weeks after DMM, mild cartilage degeneration was evident in the medial compartment, small osteophytes were present, and subchondral bone sclerosis was established. By 16 weeks after surgery, significant cartilage deterioration was apparent on the medial tibial plateaux and medial femoral condyles, osteophyte size had increased, and subchondral bone sclerosis was maintained. Treatment with ADAMTS-5 mAb from week 4 to 16 after surgery slowed cartilage degeneration and osteophyte growth but did not affect subchondral bone sclerosis. Moreover, ADAMTS-5 blockade resulted in temporary reversal of mechanical allodynia, which correlated with decreased MCP-1 production by cultured DRG cells. CONCLUSIONS: This study suggests therapeutic efficacy of an ADAMTS-5 mAb in the DMM model, when therapy starts early in disease.
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Proteínas ADAM/antagonistas & inhibidores , Anticuerpos Neutralizantes/farmacología , Quimiocina CCL2/efectos de los fármacos , Ganglios Espinales/efectos de los fármacos , Hiperalgesia/fisiopatología , Nocicepción/efectos de los fármacos , Osteoartritis de la Rodilla/fisiopatología , Rodilla de Cuadrúpedos/efectos de los fármacos , Proteínas ADAM/inmunología , Proteína ADAMTS5 , Animales , Quimiocina CCL2/metabolismo , Modelos Animales de Enfermedad , Ganglios Espinales/citología , Ganglios Espinales/metabolismo , Hiperalgesia/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Osteoartritis de la Rodilla/metabolismo , Lesiones de Menisco TibialRESUMEN
OBJECTIVE/METHOD: Aggrecanase activity, most notably ADAMTS-5, is implicated in pathogenic cartilage degradation. Selective monoclonal antibodies (mAbs) to both ADAMTS-5 and ADAMTS-4 were generated and in vitro, ex vivo and in vivo systems were utilized to assess target engagement, aggrecanase inhibition and modulation of disease-related endpoints with the intent of selecting a candidate for clinical development in osteoarthritis (OA). RESULTS: Structural mapping predicts the most potent mAbs employ a unique mode of inhibition by cross-linking the catalytic and disintegrin domains. In a surgical mouse model of OA, both ADAMTS-5 and ADAMTS-4-specific mAbs penetrate cartilage following systemic administration, demonstrating access to the anticipated site of action. Structural disease modification and associated alleviation of pain-related behavior were observed with ADAMTS-5 mAb treatment. Treatment of human OA cartilage demonstrated a preferential role for ADAMTS-5 inhibition over ADAMTS-4, as measured by ARGS neoepitope release in explant cultures. ADAMTS-5 mAb activity was most evident in a subset of patient-derived tissues and suppression of ARGS neoepitope release was sustained for weeks after a single treatment in human explants and in cynomolgus monkeys, consistent with high affinity target engagement and slow ADAMTS-5 turnover. CONCLUSION: This data supports a hypothesis set forth from knockout mouse studies that ADAMTS-5 is the major aggrecanase involved in cartilage degradation and provides a link between a biological pathway and pharmacology which translates to human tissues, non-human primate models and points to a target OA patient population. Therefore, a humanized ADAMTS-5-selective monoclonal antibody (GSK2394002) was progressed as a potential OA disease modifying therapeutic.
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Proteínas ADAM/inmunología , Anticuerpos Monoclonales/farmacología , Cartílago Articular/patología , Osteoartritis/inmunología , Proteínas ADAM/antagonistas & inhibidores , Agrecanos/metabolismo , Animales , Cartílago Articular/metabolismo , Modelos Animales de Enfermedad , Epítopos/metabolismo , Humanos , Ratones , Osteoartritis/metabolismoRESUMEN
Ovarian clear cell carcinomas (OCCCs) account for about 5-13% of all epithelial ovarian carcinomas in Western populations. It is characterised by resistance to conventional platinum-based chemotherapy, and new therapeutic strategies are urgently required. This article will focus on how recent discoveries have enhanced our understanding of the molecular pathogenesis of OCCCs, leading to new therapeutic opportunities. These include mutations in ARID1A, which provides a link to endometriosis, upregulation of the phosphatidylinositol 3-kinase/AKT pathway, particularly through mutations of PIK3CA and inactivation of PTEN, and increased activity of pathways involved in angiogenesis. Targeting HER2, apoptotic escape mechanisms and mismatch repair defects offer additional opportunities for treating this enigmatic tumour subtype.
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Adenocarcinoma de Células Claras/tratamiento farmacológico , Terapia Molecular Dirigida/métodos , Neoplasias Ováricas/tratamiento farmacológico , Adenocarcinoma de Células Claras/metabolismo , Animales , Femenino , Humanos , Neoplasias Ováricas/metabolismoRESUMEN
Producing enough food to meet the needs of an increasing global population is one of the greatest challenges we currently face. The issue of food security is further complicated by impacts of elevated CO2 and climate change. In this viewpoint article, we begin to explore the impacts of elevated CO2 on two specific aspects of plant nutrition and resource allocation that have traditionally been considered separately. First, we focus on arbuscular mycorrhizas, which play a major role in plant nutrient acquisition. We then turn our attention to the allocation of resources (specifically N and C) in planta, with an emphasis on the secondary metabolites involved in plant defence against herbivores. In doing so, we seek to encourage a more integrated approach to investigation of all aspects of plant responses to eCO2.
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OBJECTIVE: The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel with or without chondrogenic factors (CF) and allogeneic bone marrow stromal cells (BMSCs) to stimulate cartilage regeneration in a full-thickness, critically-sized, rabbit cartilage defect model in vivo. We used CF treatments to test the hypotheses that CF would stimulate chondrogenesis and matrix production by cells migrating into acellular KLD (KLD+CF) or by BMSCs delivered in KLD (KLD+CF+BMSCs). DESIGN: Three groups were tested against contralateral untreated controls: KLD, KLD+CF, and KLD+CF+BMSCs, n=6-7. Transforming growth factor-ß1 (TGF-ß1), dexamethasone, and insulin-like growth factor-1 (IGF-1) were used as CF pre-mixed with KLD and BMSCs before injection. Evaluations included gross, histological, immunohistochemical and radiographic analyses. RESULTS: KLD without CF or BMSCs showed the greatest repair after 12 weeks with significantly higher Safranin-O, collagen II immunostaining, and cumulative histology scores than untreated contralateral controls. KLD+CF resulted in significantly higher aggrecan immunostaining than untreated contralateral controls. Including allogeneic BMSCs+CF markedly reduced the quality of repair and increased osteophyte formation compared to KLD-alone. CONCLUSIONS: These data show that KLD can fill full-thickness osteochondral defects in situ and improve cartilage repair as shown by Safranin-O, collagen II immunostaining, and cumulative histology. In this small animal model, the full-thickness critically-sized defect provided access to the marrow, similar in concept to abrasion arthroplasty or spongialization in large animal models, and suggests that combining KLD with these techniques may improve current practice.
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Cartílago Articular/lesiones , Condrogénesis/fisiología , Trasplante de Células Madre Mesenquimatosas/métodos , Ingeniería de Tejidos/métodos , Animales , Células de la Médula Ósea/citología , Cartílago Articular/diagnóstico por imagen , Cartílago Articular/patología , Cartílago Articular/fisiología , Condrogénesis/efectos de los fármacos , Dexametasona/farmacología , Femenino , Hidrogeles , Factor I del Crecimiento Similar a la Insulina/farmacología , Conejos , Radiografía , Regeneración/efectos de los fármacos , Membrana Sinovial/patología , Andamios del Tejido , Factor de Crecimiento Transformador beta1/farmacologíaRESUMEN
The relationships between various leaf functional traits that are important in plant growth (e.g., specific leaf area) have been investigated in recent studies; however, research in this context on plants that are highly protected by chemical defences, particularly resource-demanding nitrogen-based defence, is lacking. We collected leaves from cyanogenic (N-defended) Beilschmiedia collina B. Hyland and acyanogenic (C-defended) Beilschmiedia tooram (F. M. Bailey) B. Hyland at high- and low-soil nutrient sites in two consecutive years that varied significantly in rainfall. We then measured the relationships between chemical defence and morphological and functional leaf traits under the different environmental conditions. We found that the two species differed significantly in their resource allocation to defence as well as leaf morphology and function. The N defended species had a higher leaf nitrogen concentration, whereas the C-defended species had higher amounts of C-based chemical defences (i.e., total phenolics and condensed tannins). The C-defended species also tended to have higher force to fracture and increased leaf toughness. In B. collina, cyanogenic glycoside concentration was higher with higher rainfall, but not with higher soil nutrients. Total phenolic concentration was higher at the high soil nutrient site in B. tooram, but lower in B. collina; however, with higher rainfall an increase was found in B. tooram, while phenolics decreased in B. collina. Condensed tannin concentration decreased in both species with rainfall and nutrient availability. We conclude that chemical defence is correlated with leaf functional traits and that variation in environmental resources affects this correlation.
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Lauraceae/fisiología , Lluvia , Suelo , Aclimatación , Carbono/metabolismo , Lauraceae/anatomía & histología , Lauraceae/metabolismo , Nitrógeno/metabolismo , Hojas de la Planta/anatomía & histología , Hojas de la Planta/química , Hojas de la Planta/metabolismo , Especificidad de la EspecieRESUMEN
The CH3-HCN and CD3-HCN radical complexes have been formed in helium nanodroplets by sequential pickup of a CH3 (CD3) radical and a HCN molecule and have been studied by high-resolution infrared laser spectroscopy. The complexes have a hydrogen-bonded structure with C3v symmetry, as inferred from the analysis of their rotationally resolved nu = 1 <-- 0 H-CN vibrational bands. The A rotational constants of the complexes are found to change significantly upon vibrational excitation of the C-H stretch of HCN within the complex, DeltaA = A'-A" = -0.04 cm(-1) (for CH3-HCN), whereas the B rotational constants are found to be 2.9 times smaller than that predicted by theory. The reduction in B can be attributed to the effects of helium solvation, whereas the large DeltaA is found to be a sensitive probe of the vibrational averaging dynamics of such weakly bound systems. The complex has a permanent electric dipole moment of 3.1 +/- 0.2 D, as measured by Stark spectroscopy. A vibration-vibration resonance is observed to couple the excited C-H stretching vibration of HCN within the complex to the lower-frequency C-H stretches of the methyl radical. Deuteration of the methyl radical was used to detune these levels from resonance, increasing the lifetime of the complex by a factor of 2. Ab initio calculations for the energies and molecular parameters of the stationary points on the CN+CH4 --> HCN+CH3 potential-energy surface are also presented.