Biomechanics of the lower limb in patients with mild knee osteoarthritis during the sit-to-stand task.

BACKGROUND: Knee osteoarthritis (KOA) is a prevalent and debilitating condition that markedly affects the sit-to-stand (STS) activity of patients, a prerequisite for daily activities. Biomechanical recognition of movements in patients with mild KOA is currently attracting attention. However, limited studies have been conducted solely on the observed differences in sagittal plane movement and muscle activation. AIM: This study aimed to identify three-dimensional biomechanical and muscle activation characteristics of the STS activity in patients with mild KOA. METHODS: A cross-sectional study was conducted to observe the differences between patients with mild KOA and a control group (CG). It was conducted to observe the differences in muscle activation, including root mean square (RMS%) and integrated electromyography (items), kinematic parameters like range of motion (ROM) and maximum angular velocity, as well as dynamic parameters such as joint moment and vertical ground reaction force (vGRF). RESULTS: Patients with mild KOA had a higher body mass index and longer task duration. In the sagittal plane, patients with KOA showed an increased ROM of the pelvic region, reduced ROM of the hip-knee-ankle joint, and diminished maximum angular velocity of the knee-ankle joint. Furthermore, patients with KOA displayed increased knee-ankle joint ROM in the coronal plane and decreased ankle joint ROM in the horizontal plane. Integrated vGRF was higher in both lower limbs, whereas the vGRF of the affected side was lower. Furthermore, patients showed a decreased peak adduction moment (PADM) and increased peak external rotation moment in the knee joint and smaller PADM and peak internal rotation moment in the ankle joint. The affected side exhibited decreased RMS% and iEMG values of the gluteus medius, vastus medialis, and vastus lateralis muscles, as well as a decreased RMS% of the rectus femoris muscle. Conversely, RMS% and iEMG values of the biceps femoris, lateral gastrocnemius, and medial gastrocnemius muscles were higher. CONCLUSION: The unbalanced activation characteristics of the anterior and posterior muscle groups, combined with changes in joint moment in the three-dimensional plane of the affected joint, may pose a potential risk of injury to the irritated articular cartilage.

Comparative evaluation of autologous platelet-rich plasma and platelet lysate in patients with knee osteoarthritis.

Autologous platelet-rich plasma (PRP) and platelet lysate (PL) are nowadays promising candidates in the treatment of articular cartilage lesions. We aimed to compare PRP and PL injection effectiveness in patients with knee osteoarthritis (KOA). A total of fifty women with KOA were included in the study. Patients were treated with intra-articular injections of PRP and PL. Clinical outcomes were evaluated using the comparison of VAS, WOMAC, and ROM scores. The concentration levels of growth factors and cytokines were measured by ELISA. All patients showed significant improvements in pain and function following treatment of KOA with PL and PRP compared to baseline. Moreover, PL's concentration of growth factors was significantly higher than PRP. A significant increase was also observed in all of the aforementioned mediators in both PRP and PL products compared to control. These results can introduce PL as a promising and alternative option for KOA therapy in the future.

Microfracture technique combined with mesenchymal stem cells inducer represses miR-708-5p to target special at-rich sequence-binding protein 2 to drive cartilage repair and regeneration in rabbit knee osteoarthritis.

Knee osteoarthritis (KOA) is a degenerative joint illness which leads to knee pain and functional limitation. In this study, we combined microfracture surgery with kartogenin (KGN), a small bioactive molecule used to promote the differentiation of mesenchymal stem cells (MSCs), and explored its impact on cartilage repair and possible latent mechanisms of action. The research offers a brand-new idea for the clinical cure of KOA. The microfracture technique in combination with KNG treatment was performed on a rabbit model of KOA. Animal behaviour was evaluated after the intra-articular injection of miR-708-5p and Special AT-rich sequence binding protein 2 (SATB2) lentiviruses. Later, the expression of the tumour necrosis factor α (TNF-α) and interleukin- 1 (IL-1), the pathology of synovial tissue and cartilage tissue, and the positive cartilage type II collagen, MMP-1, MMP-3 and TIMP-1 were detected. Finally, a luciferase assay was conducted to verify the interaction of miR-708-5p and SATB2. Our results showed that miR-708-5p was elevated in the rabbit KOA model; however, the expression of SATB2 was reduced. Meanwhile, the microfracture technology combined with MSCs inducer KGN drove cartilage repair and regeneration in rabbit KOA by repressing the miR-708-5p expression. We also found that miR-708-5p directly targeted the SATB2 mRNA to regulate its expression. Furthermore, our data urged that elevating miR-708-5p or restraining SATB2 may reverse the therapeutic effect of the microfracture technique combined with MSCs inducer on rabbit KOA. Microfracture technique combined with MSCs inducer represses miR-708-5p to target SATB2 to drive cartilage repair and regeneration in rabbit KOA. This indicates that the microfracture technique combined with MSCs inducers is supposed to be an effective latent method for osteoarthritis cure.

Integrative analysis of physiology and genomics provides insights into freeze tolerance adaptations of Acacia koa along an elevational cline.

Natural selection for plant species in heterogeneous environments creates genetic variation for traits such as cold tolerance. While physiological or molecular analyses have been used to evaluate stress tolerance adaptations, combining these approaches may provide deeper insight. Acacia koa (koa) occurs from sea level to 2300 m in Hawai'i, USA. At high elevations, natural koa populations have declined due to deforestation, and freeze tolerance is a limiting factor for tree regeneration. We used physiology and molecular analyses to evaluate cold tolerance of koa populations from low (300-750 m), middle (750-1500 m), and high elevations (1500-2100 m). Half of the seedlings were cold acclimated by exposure to progressively lowered air temperatures for eight weeks (from 25.6/22.2°C to 8/4°C, day/night). Using the whole plant physiology-freezing test and koa C-repeat Binding Factor CBF genes, our results indicated that koa can be cold-acclimated when exposed to low, non-freezing temperatures. Seedlings from high elevations had consistently higher expression of Koa CBF genes associated with cold tolerance, helping to explain variation in cold-hardy phenotypes. Evaluation of the genetic background of 22 koa families across the elevations with low coverage RNA sequencing indicated that high elevation koa had relatively low values of heterozygosity, suggesting that adaptation is more likely to arise in the middle and low elevation sources. This physiology and molecular data for cold tolerance of koa across the elevation gradient of the Hawaiian Islands provides insights into natural selection processes and may help to support guidelines for conservation and seed transfer in forest restoration efforts.

Octanol/Air Partition Coefficient─A General-Purpose Fragment Model to Predict Log Koa from Molecular Structure.

The octanol/air partition coefficient Koa is important for assessing the bioconcentration of airborne xenobiotics in foliage and in air-breathing organisms. Moreover, Koa informs about compound partitioning to aerosols and indoor dust, and complements the octanol/water partition coefficient Kow and the air/water partition coefficient Kaw for multimedia fate modeling. Experimental log Koa at 25 °C has been collected from literature for 2161 compounds with molecular weights from 16 to 959 Da. The curated data set covers 18.2 log units (from -1.0 to 17.2). A newly developed fragment model for predicting log Koa from molecular structure outperforms COSMOtherm, EPI-Suite KOAWIN, OPERA, and linear solvation energy relationships (LSERs) regarding the root-mean-squared error (rms) and the maximum negative and positive errors (mne and mpe) (rms: 0.57 vs 0.86 vs 1.09 vs 1.19 vs 1.05-1.53, mne: -2.55 vs -3.95 vs -7.51 vs -7.54 vs (-5.63) - (-7.34), mpe: 2.91 vs 5.97 vs 7.54 vs 4.24 vs 6.89-10.2 log units). The prediction capability, statistical robustness, and sound mechanistic basis are demonstrated through initial separation into a training and prediction set (80:20%), mutual leave-50%-out validation, and target value scrambling in terms of temporarily wrong compound-Koa allocations. The new general-purpose model is implemented in a fully automatized form in the ChemProp software available to the public. Regarding Koa indirectly determined through Kow and Kaw, a new approach is developed to convert from wet to dry octanol, enabling higher consistency in experimental (and thus also predicted) Koa.

Neuroplasticity changes in knee osteoarthritis (KOA) indexed by event-related desynchronization/synchronization during a motor inhibition task.

PURPOSE: Event-related desynchronisation (ERD) and event-related synchronisation (ERS) reflect pain perception and integration of the nociceptive sensory inputs. This may contribute to the understanding of how neurophysiological markers of Knee Osteoarthritis (KOA) patients can differ from control individuals, which would improve aspects such as prediction and prognosis. We performed a cross-sectional analysis of our cohort study (DEFINE cohort), KOA arm, with 71 patients, compared with 65 control participants. The study aimed to examine possible differences between ERD and ERS in control participants compared to Knee Osteoarthritis (KOA) patients when adjusting for important covariates. MATERIALS AND METHODS: We performed independent multivariate regression models considering as dependent variables the power value related to ERD and ERS for four different sensorimotor tasks (Motor Execution, Motor Imagery, Active Observation and Passive Observation) and four sensorimotor oscillations (Alpha, Beta, Low Beta, and High Beta), each model, controlled by age and sex. RESULTS: We demonstrate that the differences between KOA and healthy subjects are frequency specific, as most differences are in the beta bandwidth range. Also, we observed that subjects in the KOA group had significantly higher ERD and ERS. This may be correlated to the amount of lack of brain organisation and a subsequent attempt at compensation induced by KOA. CONCLUSIONS: Our findings strengthen the notion that subjects with KOA have a higher degree of brain plasticity changes that are also likely correlated to the degree of compensation and behavioural dysfunction.

The impact of post-traumatic stress on the clinical outcome in a cohort of patients with knee osteoarthritis and knee arthroplasty: A prospective study.

BACKGROUND: Knee osteoarthritis (KOA) is one of the most common musculoskeletal disorders and commonly occurs in older adults, predominantly female populations. Both populations have intimate links with trauma-related stress. Therefore, we intended to evaluate the prevalence of post-traumatic stress disorder (PTSD), which arises from KOA and determine its effects on the postoperative results in patients undergoing total knee arthroplasty (TKA). METHODS: The patients who fulfilled the diagnosis of KOA from February 2018 to October 2020 were interviewed. Patients were interviewed by a senior psychiatrist about evaluating their overall experience during their most difficult or stressful situations. KOA patients who underwent TKA were further analyzed to investigate whether PTSD influences the postoperative results. The PTSD Checklist-Civilian Version (PCL-C) and Western Ontario McMaster Universities (WOMAC) Osteoarthritis Index were used to assess PTS symptoms and clinical outcomes after TKA, respectively. RESULTS: 212 KOA patients completed this study with a mean follow-up of 16.7 months (7-36 months). The mean age was 62.5 ± 12.3 years, and 53.3% (113/212) were women. 64.6% of the sample (137/212) underwent TKA to relieve the symptoms of KOA. Patients with either PTS or PTSD tended to be younger (P < 0.05), female (P < 0.05) and undergo TKA (P < 0.05) than their counterparts. WOMAC-pain (P < 0.05), WOMAC-stiffness (P < 0.05), and WOMAC-physical function (P < 0.05) both before TKA and 6 months after TKA in the PTSD group is significantly higher compared to their counterparts. Logistic regression analysis showed that a history of OA-inducing trauma (adjusted OR = 2.0, 95% CI = 1.7-2.3, P = 0.003), posttraumatic KOA (adjusted OR = 1.7, 95% CI = 1.4-2.0, P < 0.001), and invasive treatment (adjusted OR = 2.0, 95% CI = 1.7-2.3, P = 0.032), were significantly associated with PTSD in KOA patients. CONCLUSIONS: Patients with KOA, especially those undergoing TKA, are associated with PTS symptoms and PTSD, indicating the need to evaluate it and offer care for them.

Spinal 5-HT2A receptor is involved in electroacupuncture inhibition of chronic pain.

Knee osteoarthritis (KOA) is a highly prevalent, chronic joint disorder, and it is a typical disease which can develop chronic pain. Our previous study has proved that endocannabinoid (2-AG)-CB1R-GABA-5-HT pathway is involved in electroacupuncture (EA) mediated inhibition of chronic pain. However, it is still unclear which among the 5-HT receptor subtype is involved in EA evoked 5-HT mediated inhibition of chronic pain in the dorsal spinal cord. 5-HT2A is a G protein-coupled receptor and it is involved in 5-HT descending pain modulation system. We found that EA treatment at frequency of 2 Hz +1 mA significantly increased the expression of 5-HT2A receptor in the dorsal spinal cord and intrathecal injection of 5-HT2A receptor antagonist or agonist reversed or mimicked the analgesic effect of EA in each case respectively. Intrathecal injection of a selective GABAA receptor antagonist Bicuculline also reversed the EA effect on pain hypersensitivity. Additionally, EA treatment reversed the reduced expression of GABAA receptor and KCC2 in the dorsal spinal cord of KOA mice. Furthermore, we demonstrated that intrathecal 5-HT2A receptor antagonist/agonist reversed or mimicked the effect of EA up-regulate of KCC2 expression, respectively. Similarly, intrathecal injection of PLC and PKC inhibitors prevented both anti-allodynic effect and up-regulation of KCC2 expression by EA treatment. Our data suggest that EA treatment up-regulated KCC2 expression through activating 5-HT2A-Gq-PLC-PKC pathway and enhanced the inhibitory function of GABAA receptor, thereby inhibiting chronic pain in a mouse model of KOA.

Can the impact of canopy trees on soil and understory be altered using litter additions?

Trees can have large effects on soil nutrients in ways that alter succession, particularly in the case of nitrogen-(N)-fixing trees. In Hawai'i, forest restoration relies heavily on use of a native N-fixing tree, Acacia koa (koa), but this species increases soil-available N and likely facilitates competitive dominance of exotic pasture grasses. In contrast, Metrosideros polymorpha ('ohi'a), the dominant native tree in Hawai'i, is less often planted because it is slow growing; yet it is typically associated with lower soil N and grass biomass, and greater native understory recruitment. We experimentally tested whether it is possible to reverse high soil N under koa by adding 'ohi'a litter, using additions of koa litter or no litter as controls, over 2.5 yr. We then quantified natural litterfall and decomposition rates of 'ohi'a and koa litter to place litter additions in perspective. Finally, we quantified whether litter additions altered grass biomass and if this had effects on native outplants. Adding 'ohi'a litter increased soil carbon, but increased rather than decreased inorganic soil N pools. Contrary to expectations, koa litter decomposed more slowly than 'ohi'a, although it released more N per unit of litter. We saw no reduction in grass biomass due to 'ohi'a litter addition, and no change in native outplanted understory survival or growth. We conclude that the high N soil conditions under koa are difficult to reverse. However, we also found that outplanted native woody species were able to decrease exotic grass biomass over time, regardless of the litter environment, making this a better strategy for lowering exotic species impacts.

A novel serological biomarker are associated with disease severity in patients with osteoarthritis.

BACKGROUND AND AIM: Apolipoprotein D (ApoD) is a 25-30 kDa glycoprotein, as a distinct component of the human plasma lipoprotein system. Its known biological functions are mainly related to lipid metabolism. The purpose of this study was to explore the potential role of ApoD concentration in knee osteoarthritis (KOA). METHODS: This study was performed in a population of 113 KOA subjects and 97 healthy controls. Serum ApoD was detected using the commercial ELISA kit (Cusabio, Wu Han, China, Cat No. CSB-EL001935HU). Radiographic progression was evaluated using Kellgren-Lawrence (KL) classification. The clinical severity of KOA was assessed by visual analog score (VAS), Hospital for special surgery (HSS) knee score disease duration and TNF-α. Receiver-operating characteristic (ROC) curve was performed to test the potential diagnostic value of ApoD in radiographic progression. RESULTS: The serum ApoD level of patients with KOA was significantly lower than that of healthy controls. The serum ApoD level was negatively correlated with KL grades, VAS score, disease duration, TNF-α concentrations. On the contrary, it was positively correlated with HSS score. However, there was no correlation between this serological indicator and which side was affected. ROC curve analysis indicated that attenuated serum ApoD could serve as an appropriate biomarker concerning the diagnosis of KOA. CONCLUSIONS: Serum ApoD concentration was correlated with the presence and severity of KOA.

Self-administered acupressure and exercise for patients with osteoarthritis: A randomized controlled trial.

OBJECTIVE: Knee osteoarthritis is a prevalent degenerative joint disease and seriously affects the athletic abilities of middle-aged and elderly patients. Acupressure is a traditional non-pharmacological intervention that promotes blood circulation and muscle activity. Self-administrated acupressure and exercise can be potential management for knee osteoarthritis. DESIGN: It is a randomized and controlled trial for knee osteoarthritis self-treatment. SETTINGS: Cangzhou Hospital. INTERVENTIONS: 221 patients with knee osteoarthritis were recruited and randomly divided into 4 groups: control group (n = 55), exercise group (n = 56), acupressure group (n = 55) and exercise & acupressure group (n = 55). In the first eight weeks, corresponding training courses were provided to different groups of patients. The patients were asked to carry out their own corresponding interventions for 16 weeks. The patient's condition was evaluated in the sixteenth week. MAIN MEASURES: The Western Ontario and McMaster Universities global scores of knee osteoarthritis patients were assessed at the 8th and 16th week of our trial. RESULTS: Self-administered acupressure and exercise significantly decreased visual analogue scale (3.75 ± 1.89 versus 2.93 ± 1.73, p < 0.05), pain (7.6 ± 2.8 versus 4.8 ± 2.7, p < 0.05), stiffness (3.75 ± 1.89 versus 2.93 ± 1.73, p < 0.05) at the 16th week (p < 0.05) in patients with knee osteoarthritis compared to other intervention. The combination of acupressure and exercise also improved the range of motion (114.4 ± 11.5 versus 120.4 ± 11.9, p < 0.05) and walk speed (1.48 ± 0.48 versus 1.76 ± 0.50, p < 0.05) of osteoarthritis patients (p < 0.05). CONCLUSION: Self-administrated exercise and acupressure alleviate the arthritic symptoms (swelling, pain, joint dysfunction and joint deformities) and improve the joint functions, supporting its potential use in the clinical management for osteoarthritis.

Prediction study on the distribution of polycyclic aromatic hydrocarbons and their halogenated derivatives in the atmospheric particulate phase.

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (X-PAHs), which generally produced from photochemical and thermal reactions of parent PAHs, widely exist in the environment. They are semi-volatile organic chemicals (SVOCs) and the partitioning between gas/particulate phases affects their environmental migration, transformation and fate, which further impacts their toxicity and health risk to human. However, there is a large data missing of the experimental distribution ratio in the atmospheric particulate phase (f), especially for X-PAHs. In this study, we first checked the correlation between experimental f values of 53 PAH derivatives and their octanol-air partitioning coefficients (log KOA), which is frequently used to characterize the distribution of chemicals in organic phase, and yielded R2 = 0.803. Then, quantum chemical descriptors derived from molecular structural optimization by M06-2X/6-311 +G (d,p) method were further employed to develop Quantitative Structure-Property Relationship (QSPR) model. The model contains two descriptors, the average molecular polarizability (α) and the equilibrium parameter of molecular electrostatic potential (τ), and yields better performance with R2 = 0.846 and RMSE = 0.122. The mechanism analysis and validation results by different strategies prove that the model can reveal the molecular properties that dominate the distribution between gas and particulate phases and it can be used to predict f values of other PAHs/X-PAHs, providing basic data for their environmental ecological risk assessment.

Atmospheric chemistry and cancer risk assessment of Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs over a semi-arid site in the Indo-Gangetic plain.

Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro-PAHs were collected over a year at a traffic dominated site in Agra, to determine the dominant partitioning mechanism. During the entire sampling period, total PAHs and Nitro-PAHs were 3465 ± 3802 and 26.1 ± 25.9 ng m-3 respectively. The gas-particle partitioning behavior of PAHs was studied by applying the Pankow model, Absorption model, and Dual model. Amongst all the partitioning models, the Dual model fits well and indicates that the partitioning of PAHs at the traffic site in Agra depends on both the physical adsorption of PAHs on the Total Suspended Particulate (TSP) surface and absorption of PAHs into the organic layer present on the TSP surface. Pankow model indicates that PAHs are emitted from the source close to the sampling point and due to this PAHs do not get enough time to get partitioned in between both the phases. Incremental lifetime Cancer Risk (ILCR) shows that adults and children are more prone to cancer risk in comparison to infants for both PAHs and Nitro-PAHs. Cancer risk by inhalation was minimum in comparison to both ingestion and dermal exposure. Nitro-PAHs in the particulate phase were high enough to exceed the minimum permissible limit (10-6) of causing cancer by ingestion and dermal exposure.

Novel Bayesian Method to Derive Final Adjusted Values of Physicochemical Properties: Application to 74 Compounds.

Accurate values of physicochemical properties are essential for screening semivolatile organic compounds for human and environmental hazard and risk. In silico approaches for estimation are widely used, but the accuracy of these and measured values can be difficult to ascertain. Final adjusted values (FAVs) harmonize literature-reported measurements to ensure consistency and minimize uncertainty. We propose a workflow, including a novel Bayesian approach, for estimating FAVs that combines measurements using direct and indirect methods and in silico values. The workflow was applied to 74 compounds across nine classes to generate recommended FAVs (FAVRs). Estimates generated by in silico methods (OPERA, COSMOtherm, EPI Suite, SPARC, and polyparameter linear free energy relationships (pp-LFER) models) differed by orders of magnitude for some properties and compounds and performed systematically worse for larger, more polar compounds. COSMOtherm and OPERA generally performed well with low bias although no single in silico method performed best across all compound classes and properties. Indirect measurement methods produced highly accurate and precise estimates compared with direct measurement methods. Our Bayesian method harmonized measured and in silico estimated physicochemical properties without introducing observable biases. We thus recommend use of the FAVRs presented here and that the proposed Bayesian workflow be used to generate FAVRs for SVOCs beyond those in this study.

Correlation between single nucleotide polymorphisms in CXCR4 microRNA binding site and the susceptibility to knee osteoarthritis in Han Chinese population.

BACKGROUND: This study aimed to investigate the relationship between single nucleotide polymorphisms (SNPs) at the microRNA target sequence in CXCR4 and the susceptibility to knee osteoarthritis (KOA). METHODS: A total of 305 patients with KOA and 305 healthy controls were recruited into this study. The genotypes of CXCR4 rs1804029 and rs17848060 loci were analyzed. RESULTS: The susceptibility to KOA of CXCR4 rs1804029 G allele carriers was 1.33 times (95% CI: 1.09-1.54, P = .006) that of T allele carriers. The KOA susceptibility in individuals carrying T allele at CXCR4 rs17848060 locus was 1.38 times that of individuals carrying A allele (95% CI: 1.17-1.57, P < .001). The G allele at CXCR4 rs1804029 locus was the target of hsa-miR-146a-3p, while the A allele at CXCR4 rs17848060 locus could be targeted by hsa-miR-20a-3p. The plasma level of hsa-miR-146a-3p was lower in rs1804029 G allele carriers than T allele carriers (P < .001), whereas plasma level of hsa-miR-20a-3p was higher in rs17848060 T allele carriers than A allele carriers (P < .001). CONCLUSION: The SNPs at rs1804029 and rs17848060 loci in CXCR4 were significantly associated with the susceptibility to KOA in Han Chinese population.

The Effect of Platelet-Rich Plasma on the Intra-Articular Microenvironment in Knee Osteoarthritis.

Knee osteoarthritis (KOA) represents a clinical challenge due to poor potential for spontaneous healing of cartilage lesions. Several treatment options are available for KOA, including oral nonsteroidal anti-inflammatory drugs, physical therapy, braces, activity modification, and finally operative treatment. Intra-articular (IA) injections are usually used when the non-operative treatment is not effective, and when the surgery is not yet indicated. More and more studies suggesting that IA injections are as or even more efficient and safe than NSAIDs. Recently, research to improve intra-articular homeostasis has focused on biologic adjuncts, such as platelet-rich plasma (PRP). The catabolic and inflammatory intra-articular processes that exists in knee osteoarthritis (KOA) may be influenced by the administration of PRP and its derivatives. PRP can induce a regenerative response and lead to the improvement of metabolic functions of damaged structures. However, the positive effect on chondrogenesis and proliferation of mesenchymal stem cells (MSC) is still highly controversial. Recommendations from in vitro and animal research often lead to different clinical outcomes because it is difficult to translate non-clinical study outcomes and methodology recommendations to human clinical treatment protocols. In recent years, significant progress has been made in understanding the mechanism of PRP action. In this review, we will discuss mechanisms related to inflammation and chondrogenesis in cartilage repair and regenerative processes after PRP administration in in vitro and animal studies. Furthermore, we review clinical trials of PRP efficiency in changing the OA biomarkers in knee joint.

Whole genome analysis of the koa wilt pathogen (Fusarium oxysporum f. sp. koae) and the development of molecular tools for early detection and monitoring.

BACKGROUND: Development and application of DNA-based methods to distinguish highly virulent isolates of Fusarium oxysporum f. sp. koae [Fo koae; cause of koa wilt disease on Acacia koa (koa)] will help disease management through early detection, enhanced monitoring, and improved disease resistance-breeding programs. RESULTS: This study presents whole genome analyses of one highly virulent Fo koae isolate and one non-pathogenic F. oxysporum (Fo) isolate. These analyses allowed for the identification of putative lineage-specific DNA and predicted genes necessary for disease development on koa. Using putative chromosomes and predicted gene comparisons, Fo koae-exclusive, virulence genes were identified. The putative lineage-specific DNA included identified genes encoding products secreted in xylem (e. g., SIX1 and SIX6) that may be necessary for disease development on koa. Unique genes from Fo koae were used to develop pathogen-specific PCR primers. These diagnostic primers allowed target amplification in the characterized highly virulent Fo koae isolates but did not allow product amplification in low-virulence or non-pathogenic isolates of Fo. Thus, primers developed in this study will be useful for early detection and monitoring of highly virulent strains of Fo koae. Isolate verification is also important for disease resistance-breeding programs that require a diverse set of highly virulent Fo koae isolates for their disease-screening assays to develop disease-resistant koa. CONCLUSIONS: These results provide the framework for understanding the pathogen genes necessary for koa wilt disease and the genetic variation of Fo koae populations across the Hawaiian Islands.

Plasticity of phenotype and heteroblasty in contrasting populations of Acacia koa.

BACKGROUND AND AIMS: Heteroblastic plant species, whose morphology or growth habit changes suddenly during development, offer unique opportunities to investigate the role of selection in canalizing development or increasing the adaptive importance of plasticity. Leaf forms of the Hawaiian tree Acacia koa (koa) change morphologically and physiologically during the first year of growth, providing time to study abiotic factors influencing transition rates relative to other Acacia species. METHODS: The roles of light and water availability in triggering transition to the mature leaf form in contrasting (wet/dry) ecotypes of koa were investigated using a novel modelling technique to distinguish between chronological and ontogenetic controls in triggering transition. A light quality treatment was included to test interactions of heterophylly (the presence of multiple leaf forms) with heteroblastic processes on the resulting phenotype at transition. KEY RESULTS: Increased light intensity increased transition rates, but reduced red to far-red light (R:FR) ratios did not affect transition rates, solidifying the current paradigm of heteroblasty. However, evidence was found for earlier transition ontogenetically under water stress, which is not part of the current paradigm and could differentiate the role of heteroblasty in some Acacia species versus other heteroblastic species. Ecotypic responses also indicate that plasticity of development could vary across koa's range and the adaptive significance of heteroblasty could be marginalized or amplified dependent on the disparate selective pressures present across koa's range. CONCLUSIONS: The use of novel survival functions and a species with an elongated transition time helped to elucidate abiotic modifiers of ontogenetic trajectories. Differences in ontogenetic trajectories between contrasting ecotypes suggest that ongoing climate and land use change will have non-uniform effects on koa regeneration and establishment dynamics across its range.

Magnetic resonance evaluation of knee osteoarthritis among the Saudi Population.

BACKGROUND AND OBJECTIVES: Osteoarthritis (OA) is the most prevalent worldwide joint degenerative disorder with high morbidities and disabilities. The current study aimed to investigate the prevalence of knee osteoarthritis (KOA) in Arar by using magnetic resonance imaging (MRI). METHODS: The prevalence of KOA was studied in Arar through MRI evaluation of randomly chosen sample from patients and their relatives attending the Prince Abdul Aziz Bin Mussad Hospital from October 2015 to November 2016. RESULTS: A total of 410 participants were enrolled in the study [328 (80%) male and 82 (20%) females]. After MRI, 163 participants [39.75% (95% CI) = 35.14 - 44.57%)] were diagnosed with KOA. The prevalence of OA was about 25.6% (95% CI = 20.8 - 31.1%) below the age of 40 years, which was found to increase by age in the enrolled volunteers. KOA prevalence was higher in females than males (75.6% and 27.7% respectively). There was a significant association between the age and genders of the participants and the prevalence of OA (p-value < 0.0001 for both variables). There was also a significant association between the age and gender of the participants and the MRI-estimated grading (p-value < 0.0001 and 0.0044 respectively). CONCLUSION: KOA is a common disease among Arar young population, especially females. Its prevalence increases by age with higher grades of severity affecting the elderly.

Point of no return for improvement of cartilage quality indicated by dGEMRIC before and after weight loss in patients with knee osteoarthritis: a cohort study.

Background It has been demonstrated that weight loss improves symptoms in obese subjects with knee osteoarthritis (KOA). A parallel change in cartilage morphology remains to be demonstrated. Purpose To demonstrate a parallel change in cartilage morphology. Material and Methods Obese patients with KOA were examined before and after weight loss over 16 weeks. Target knee joints were radiographically assessed by the Kellgren/Lawrence grading (KLG) system. Patients with KLG-1 and 2 changes in the lateral compartment were included. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was performed using intra-articular contrast. Results Nine patients with lateral KLG-1 and ten patients with lateral KLG-2 were studied. There were no group differences regarding the lateral compartment baseline dGEMRIC T1 values: median = 497 ms (KLG-1) and 533 ms (KLG-2) ( P = 0.12), or regarding reduction in body mass index (BMI) after 16 weeks: 12.8% versus 11.4% ( P = 0.74). In the KLG-1 group, several cases of increased dGEMRIC T1 values were seen and median value decreased significantly less than in KLG-2 group (15 ms versus 41 ms, P = 0.03) after weight loss. Conclusion Improvement of cartilage quality, assessed with dGEMRIC, after weight loss might be possible in early stage KOA (KLG-1), but not in later stage KOA (KLG-2). The results may suggest a point of no return for improvement of cartilage quality that should be tested in larger trials.