RESUMO
To investigate the causal relationship between rheumatoid arthritis (RA) and ankylosing spondylitis using Mendelian randomization (MR). Genetic loci independently associated with RA and ankylosing spondylitis in people of European origin were selected as instrumental variables using pooled data from large-scale genome-wide association studies. Three MR analyses, MR-Egger, weighted median, and inverse variance weighting, were used to investigate the causal relationship between RA and ankylosing spondylitis. Heterogeneity and multiplicity tests were used, and a sensitivity test using the "leave-one-out" method was used to explore the robustness of the results. The inverse variance weighting results showed an OR (95 % CI) of 1.25 (1.11-1.41), Pâ <â .001, indicating a causal relationship between RA and ankylosing spondylitis. And no heterogeneity and pleiotropy were found by the test and sensitivity analysis also showed robust results. The present study was conducted to analyze and explore the genetic data using two-sample MR analysis and the results showed that there is a causal relationship between RA and the occurrence of ankylosing spondylitis.
Assuntos
Artrite Reumatoide , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Espondilite Anquilosante , Espondilite Anquilosante/genética , Humanos , Artrite Reumatoide/genética , Artrite Reumatoide/complicações , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo ÚnicoRESUMO
To investigate the efficacy of chiropractic rehabilitation therapy in Crowe IV developmental dysplasia of the hip (DDH) patients after total hip arthroplasty. Seventy-two patients with Crowe IV type DDH hospitalized in the Department of Orthopedics I of Ya'an Hospital of Traditional Chinese Medicine from January 2021 to June 2023 were selected for the study, and they were divided into 36 cases in the chiropractic rehabilitation therapy group (the treatment group) and 36 cases in the traditional rehabilitation therapy group (the control group) according to the method of randomized grouping. All patients were evaluated at preoperative, 1, 3, and 6 months postoperatively for follow-up, and the muscle strength of the affected limb, the patient's walking gait, the shortened length of the affected limb, the visual analog scale score (VAS score), the Oswestry Dysfunction Index Score (ODI score), the Harris Hip Score, and the degree of pelvic tilt were recorded to evaluate the results of the study. A total of 4 subjects withdrew from the study, 2 in the treatment group, and 2 in the control group. The muscle strength of the affected limb, walking gait, shortened length of the affected limb, VAS score, ODI score, Harris score, and pelvic tilt in the treatment and control groups improved significantly compared with the preoperative period. Comparisons between the 2 groups revealed that at the final follow-up visit, the limp gait of the patients in the treatment group was significantly reduced, the shortened length of the affected limb was significantly reduced, the VAS score was significantly reduced, and the ODI score was significantly reduced, in the treatment group relative to that of the control group, Harris Hip Score was significantly improved, and the degree of pelvic tilt was significantly reduced, but the improvement in muscle strength of the affected limb was not statistically significant. In future clinical practice, we recommend that chiropractic rehabilitation be used as a routine adjunctive treatment after TKA in patients with Crowe IV DDH to optimize outcomes and improve patients' quality of life.
Assuntos
Artroplastia de Quadril , Humanos , Feminino , Masculino , Artroplastia de Quadril/reabilitação , Pessoa de Meia-Idade , Manipulação Quiroprática/métodos , Força Muscular , Resultado do Tratamento , Idoso , Displasia do Desenvolvimento do Quadril/cirurgia , Displasia do Desenvolvimento do Quadril/reabilitação , Adulto , Marcha/fisiologiaRESUMO
The aim was to investigate the independent risk factors for postoperative incisional infection in ankle fractures and to establish a nomogram prediction model accordingly. Data were collected from ankle fracture patients in the Affiliated Hospital of Xinjiang Medical University from January 2018 to December 2022. Univariate and multivariate logistic regression analyses were used to determine the independent risk factors for postoperative incisional infection in ankle fractures and to establish the corresponding nomogram. Receiver operating characteristic curves were plotted and area under the curve was calculated, and calibration curves and decision curve analysis were plotted to evaluate the model performance. A total of 722 patients with ankle fractures were included in the study, and 76 patients developed postoperative incisional infections, with an incidence of 10.53%. After univariate and multivariate logistic regression analysis, a total of 5 variables were identified as independent risk factors for postoperative incisional infection in ankle fractures, namely, ageâ ≥â 60 years (OR, 1.885; 95% CI, 1.156-3.045), having diabetes (OR1.625; 95% CI, 1.095-2.876), open fracture (OR, 5.564; 95% CI, 3.099-9.990), albuminâ <â 35 g/L (OR, 2.618; 95% CI, 1.217-4.215), and operative timeâ ≥â 2 hours (OR, 1.606; 95% CI, 1.077-3.247). The nomogram for postoperative incisional infection after ankle fracture constructed in this study has good predictive accuracy and helps orthopedic surgeons to intervene earlier in patients at high risk of postoperative incisional infection after ankle fracture.
Assuntos
Fraturas do Tornozelo , Humanos , Pessoa de Meia-Idade , Fraturas do Tornozelo/cirurgia , Nomogramas , Infecção da Ferida Cirúrgica/diagnóstico , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/etiologia , Albuminas , Calibragem , Estudos RetrospectivosRESUMO
To investigate the causal relationship between dried fruit intake and meniscal injuries using Mendelian randomization (MR). Data were pooled from large-scale genome wide association studies (GWAS), and genetic loci independently associated with dry fruit intake and meniscal injuries in populations of European origin were selected as instrumental variables. Three MR analyses, inverse variance weighting (IVW), weighted median (WME) and MR-Egger, were used to investigate the causal relationship between dried fruit intake and meniscal injuries. The results were tested for robustness by heterogeneity and multiplicity tests, and sensitivity analyses were performed using the "leave-one-out" method. The IVW results showed an OR (95 % CI) of 0.47 (0.28-0.78), Pâ =â .003, indicating a causal relationship between dried fruit intake and meniscus injury. And no heterogeneity and multiplicity were found by the test and sensitivity analysis also showed robust results. The present study used a 2-sample MR analysis, and by analyzing and exploring the genetic data, the study showed that too little intake of dry fruits is a risk factor for meniscal injuries.
Assuntos
Frutas , Menisco , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , CausalidadeRESUMO
To investigate the causal relationship between ever smoked and frozen shoulder using a Mendelian randomization (MR) approach. Pooled data from a large-scale genome-wide association study were used. Genetic loci that were independent of each other and associated with ever smoked and frozen shoulder in populations of European ancestry were selected as instrumental variables. Inverse variance weighting was used as the primary analysis method. Weighted median and MR-Egger were used as complementary analysis methods to assess causal effects. To explore the causal relationship between ever smoked and frozen shoulder. Sensitivity test analysis was performed using heterogeneity test, multiple validity test, and leave-one-out analysis to explore the robustness of the results. Inverse variance weighting results of ever smoked showed an OR = 2.49, 95% CI = 1.05-5.91, P = .038, indicating that ever smoked is a risk factor for a frozen shoulder. And the test revealed no heterogeneity and pleiotropy, and the sensitivity analysis also showed robust results. This study used two-sample MR analysis to analyze and explore the genetic data, and the results showed a higher prevalence of frozen shoulder in patients with ever smoked, suggesting that active control of ever smoked may reduce the occurrence of frozen shoulder.
Assuntos
Bursite , Fumaça , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , CausalidadeRESUMO
To investigate the causal relationship between depression and frozen shoulder using a Mendelian randomization (MR) approach. Pooled data from a large-scale genome-wide association study were used. Genetic loci that were independent of each other and associated with depression and frozen shoulder in populations of European ancestry were selected as instrumental variables. Inverse variance weighting was used as the primary analysis method. Weighted median and MR-Egger were used as complementary analysis methods to assess causal effects. To explore the causal relationship between depression and frozen shoulder. Sensitivity test analysis was performed using heterogeneity test, multiple validity test, and leave-one-out analysis to explore the robustness of the results. Inverse variance weighting results showed an odds ratio (95% confidence interval) of 1.18 (0.91-1.53), Pâ =â .204, indicating that depression was not causally related to the development of frozen shoulder. And the test revealed no heterogeneity and pleiotropy, and the sensitivity analysis also showed robust results. In this study, genetic data were analyzed and explored using a two-sample MR analysis, and the results showed no causal relationship between depression and the occurrence of frozen shoulder, requiring the inclusion of a larger sample for the study.
Assuntos
Bursite , Depressão , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , CausalidadeRESUMO
To investigate the causal relationship between breast cancer and frozen shoulder using a Mendelian randomization (MR) approach. Pooled data from a large-scale genome-wide association study were used. Genetic loci that were independent of each other and associated with breast cancer and frozen shoulder in populations of European ancestry were selected as instrumental variables. Inverse variance weighting was used as the primary analysis method. Weighted median (WME) and MR-Egger were used as complementary analysis methods to assess causal effects. To explore the causal relationship between breast cancer and frozen shoulder. Sensitivity test analysis was performed using heterogeneity test, multiple validity test, and leave-one-out analysis to explore the robustness of the results. Inverse variance weighting results showed an OR (95% CI) of 1.02 (1.00-1.04), Pâ =â .048, indicating that breast cancer is a risk factor for a frozen shoulder. And the test revealed no heterogeneity and pleiotropy, and the sensitivity analysis also showed robust results. In this study, genetic data were analyzed and explored using two-sample MR analysis, and the results showed that the incidence of frozen shoulder was higher in breast cancer patients, suggesting that screening for frozen shoulder in breast cancer patients should be increased.
Assuntos
Neoplasias da Mama , Bursite , Humanos , Feminino , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , CausalidadeRESUMO
Chondrosarcoma is the second most common primary bone malignancy with the highest incidence in middle-aged and elderly people, where distant metastasis (DM) still leads to poor prognosis. The purpose of this study was to construct a nomogram for studying the diagnosis of DM in middle-aged and elderly patients with chondrosarcoma. Data on chondrosarcoma patients aged ≥ 40 years diagnosed from 2004 to 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The data were divided into a training set and an internal validation set according to a 7:3 ratio, and the training set data were screened for independent risk factors for DM in chondrosarcoma patients using univariate and multivariate logistic regression analysis. The screened independent risk factors were then used to build a nomogram. In addition, data from 144 patients with chondrosarcoma aged ≥ 40 years diagnosed in a tertiary hospital in China from 2012 to 2021 were collected as the external validation set. The results were evaluated by receiver operating characteristic curves, calibration curves, and decision curve analysis in the training set, internal validation set, and external validation set. A total of 1462 middle-aged and elderly patients with chondrosarcoma were included, and 92 (6.29%) had DM at the time of diagnosis. Independent risk factors for DM in middle-aged and elderly patients with chondrosarcoma included being married (OR: 2.119, 95% CI: 1.094-4.105), histological type of dedifferentiated chondrosarcoma (OR: 1.290, 95% CI: 1.110-1.499), high-grade tumor (OR: 1.511, 95% CI: 1.079-2.115), T3 stage (OR: 4.184, 95% CI: 1.977- 8.858), and N1 staging (OR: 5.666, 95% CI: 1.964-16.342). The area under the receiver operating characteristic curve (AUC) was 0.857, 0.820, and 0.859 in the training set, internal validation set, and external validation set, respectively. The results of the calibration curve and decision curve analysis also confirmed that the established nomogram could accurately predict DM in middle-aged and elderly patients with chondrosarcoma. Married, histological type of dedifferentiated chondrosarcoma, high-grade tumor, T3 stage, and N1 stage are independent risk factors for DM in middle-aged and elderly chondrosarcoma patients, and clinicians should see more attention.
Assuntos
Neoplasias Ósseas , Condrossarcoma , Segunda Neoplasia Primária , Idoso , Pessoa de Meia-Idade , Humanos , Calibragem , China , Nomogramas , Fatores de Risco , Programa de SEER , PrognósticoRESUMO
To investigate the causal relationship between attention deficit and hyperactivity disorder (ADHD) and frozen shoulder using Mendelian randomization (MR). Data were pooled from large-scale genome wide association studies, and genetic loci that were independent of each other and associated with ADHD and frozen shoulder in people of European ancestry were selected as instrumental variables. Three MR analyses, inverse variance weighting, weighted median and MR-Egger, were used to investigate the causal relationship between ADHD and frozen shoulder. Heterogeneity and multiplicity tests were used, and sensitivity analyses were performed using the "leave-one-out" method to explore the robustness of the results. The inverse variance weighting results showed an OR (95 % CI) of 1.12 (1.00-1.25), P = .046, indicating a causal relationship between ADHD and frozen shoulder. And no heterogeneity and multiplicity were found by the test and sensitivity analysis also showed robust results. The present study used a two-sample MR analysis, and by analyzing and exploring the genetic data, the study showed that ADHD is a risk factor for developing frozen shoulder, and patients with ADHD are more likely to suffer from frozen shoulder.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Bursite , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , CausalidadeRESUMO
To investigate the causal relationship between dried fruit intake and frozen shoulder using Mendelian randomization (MR). Genome wide association studies were conducted to pool data and select genetic loci independently associated with dried fruit intake and frozen shoulder in people of European ancestry as instrumental variables. Three MR analyses, inverse variance weighting, weighted median and MR-Egger, were used to investigate the causal relationship between dried fruit intake and frozen shoulder. Heterogeneity and multiplicity tests were used, and sensitivity analyses were conducted using the leave-one-out method to explore the robustness of the results. The inverse variance weighting results showed an OR (95 % CI) of 0.52 (0.34-0.80), Pâ =â .003, suggesting that there is a causal relationship between dried fruit intake and frozen shoulder. And no heterogeneity and multiplicity were found by the test and sensitivity analysis also showed robust results. The present study used a two-sample MR analysis, and by analyzing and exploring the genetic data, the study showed that too little intake of dry fruits is a risk factor for developing frozen shoulder.
Assuntos
Bursite , Frutas , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Causalidade , Bursite/genéticaRESUMO
To investigate the causal relationship between metformin use and osteoporosis and different subtypes of osteoporosis using a 2-sample Mendelian randomization method. Data from genome-wide association studies were analyzed, with the exposure factor being metformin and the outcome variables being osteoporosis and different subtypes. Mendelian randomization was performed using Inverse Variance Weighted (IVW), MR-Egger, and weight median (WM) methods, and heterogeneity tests, horizontal multivariate analyses, and sensitivity analyses were performed. The IVW method analysis with metformin and osteoporosis showed Pâ =â 1.53E-04, OR (95%CI)â =â 1.81E-02 (2.27E-02-1.44E-01); the IVW method analysis with metformin and postmenopausal osteoporosis with pathologic fracture showed Pâ =â 2.22E-01, OR (95%CI)â =â 4.89E-02 (3. 83E-04-6.23Eâ +â 00); the IVW method using metformin with osteoporosis with pathological fracture showed that Pâ =â 2.14E-01, OR (95%CI)â =â 1.64Eâ +â 00(5.78E-02-6.44E-04); the IVW method using metformin with pharmacological osteoporosis with pathological fracture showed that Pâ =â 9. 83E- 01, OR (95%CI)â =â 1.11Eâ +â 00 (3.99E-05-3.11Eâ +â 04); IVW method of metformin use and pharmacological osteoporosis showed that Pâ =â 5.99E-01, OR (95%CI)â =â 2.27Eâ +â 01 (2.00E-04-2.57Eâ +â 06); there is a causal relationship between metformin use and osteoporosis, but there is no causal relationship between metformin use and postmenopausal osteoporosis with pathological fracture, osteoporosis with pathological fracture, pharmacological osteoporosis, and pharmacological osteoporosis with pathological fracture, and metformin use is a protective factor for osteoporosis.
Assuntos
Fraturas Espontâneas , Metformina , Osteoporose Pós-Menopausa , Osteoporose , Humanos , Feminino , Osteoporose Pós-Menopausa/tratamento farmacológico , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Osteoporose/tratamento farmacológico , Osteoporose/epidemiologia , Osteoporose/genética , Metformina/efeitos adversosRESUMO
To investigate the causal relationship between hypothyroidism and frozen shoulder using a Mendelian randomization (MR) approach. Pooled data from a large-scale genome-wide association study (GWAS) were used. Genetic loci that were independent of each other and associated with hypothyroidism and frozen shoulder in populations of European ancestry were selected as instrumental variables. Inverse variance weighting (IVW) was used as the primary analysis method. Weighted median (WME) and MR-Egger were used as complementary analysis methods to assess causal effects. To explore the causal relationship between hypothyroidism and frozen shoulder. Sensitivity test analysis was performed using heterogeneity test, multiple validity test, and leave-one-out analysis to explore the robustness of the results. IVW results showed an OR (95% CI) of 1.07 (1.01-1.14), P = .024, indicating that hypothyroidism is a risk factor for a frozen shoulder. And no pleiotropy was found by the test, and sensitivity analysis also showed robust results. This study used 2-sample MR analysis to analyze and explore the genetic data, and the results showed a higher prevalence of frozen shoulder in patients with hypothyroidism, suggesting that active control of hypothyroidism may reduce the occurrence of frozen shoulder.
Assuntos
Bursite , Hipotireoidismo , Humanos , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Causalidade , Bursite/genética , Hipotireoidismo/complicações , Hipotireoidismo/genéticaRESUMO
The aim was to study the independent risk factors for chronic low back pain after lumbar compression fractures undergoing percutaneous kyphoplasty (PKP), and to establish a nomogram prediction model accordingly. Data were collected from patients with lumbar compression fractures from January 2017 to December 2021 at the Affiliated Hospital of Xinjiang Medical University. Univariate and multivariate logistic regression analyses were used to determine the independent risk factors for chronic low back pain after receiving PKP for lumbar compression fractures, and the corresponding nomogram was established. Receiver operating characteristic (ROC) curves were plotted and area under the curve (AUC) was calculated, and calibration curves and decision curve analysis (DCA) were plotted to evaluate the model performance. A total of 792 patients with lumbar compression fractures were included in the study, and 188 patients had chronic postoperative low back pain, with an incidence of 23.74%. After univariate and multivariate logistic regression analysis, a total of 5 variables were identified as independent risk factors for chronic low back pain after undergoing PKP for lumbar compression fractures, namely having diabetes (OR, 1.607; 95% CI, 1.157-3.205), preoperative T value < -2.5 SD (OR, 2.697; 95% CI, 1.417-5.021), multiple lumbar fractures (OR, 1.815; 95% CI, 1.415-3.201), lumbar compression ≥ 50% (OR, 2.854; 95% CI, 1.411-6.524), and bone cement leakage (OR, 2.911; 95% CI, 1.715-6.817). The nomogram for chronic low back pain after PKP for lumbar compression fractures constructed in this study has good predictive accuracy and helps orthopedic surgeons to intervene earlier in patients at high risk of chronic low back pain after undergoing PKP for lumbar compression fractures.
Assuntos
Fraturas por Compressão , Cifoplastia , Dor Lombar , Fraturas por Osteoporose , Fraturas da Coluna Vertebral , Humanos , Cifoplastia/efeitos adversos , Fraturas por Compressão/complicações , Dor Lombar/complicações , Nomogramas , Fraturas da Coluna Vertebral/complicações , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento , Fraturas por Osteoporose/cirurgia , Estudos Retrospectivos , Cimentos ÓsseosRESUMO
Chondrosarcoma is the second largest bone malignancy after osteosarcoma and mainly affects middle-aged adults, where patients with distant metastasis (DM) often have a poor prognosis. Although nomograms have been widely used to predict distant tumor metastases, there is a lack of large-scale data studies for the diagnostic evaluation of DM in chondrosarcoma. Data on patients diagnosed with chondrosarcoma from 2004 to 2015 were obtained from the Surveillance, Epidemiology, and End Results database. Independent risk factors for having DM from chondrosarcoma were screened using univariate and multivariate logistics regression analysis. A nomogram was created to predict the probability of DM from the screened independent risk factors. The nomogram was then validated using receiver operating characteristic curves and calibration curves. A total of 1870 chondrosarcoma patients were included in the study after data screening, of which 157 patients (8.40%) had DM at the time of diagnosis. Univariate and multivariate logistic regression analysis screened four independent risk factors, including grade, tumor number, T stage, and N stage. receiver operating characteristic curves and calibration curves showed good accuracy of the nomogram in both training and validation sets. The current study screened for independent risk factors for DM from chondrosarcoma, which will help clinicians evaluate patients.
Assuntos
Neoplasias Ósseas , Condrossarcoma , Segunda Neoplasia Primária , Osteossarcoma , Adulto , Pessoa de Meia-Idade , Humanos , Condrossarcoma/epidemiologia , Pesquisa , Calibragem , Fatores de Risco , Neoplasias Ósseas/epidemiologiaRESUMO
Osteosarcoma is the most common bone malignancy. There are many studies on the prognostic factors of children and adolescents, but the characteristics and prognostic factors of adult osteosarcoma are rarely studied. The aim of this study was to construct a nomogram for predicting the prognosis of adult osteosarcoma. Information on all osteosarcoma patients aged ≥ 18 years from 2004 to 2015 was downloaded from the surveillance, epidemiology and end results database. A total of 70% of the patients were included in the training set and 30% of the patients were included in the validation set. Univariate log-rank analysis and multivariate cox regression analysis were used to screen independent risk factors affecting the prognosis of adult osteosarcoma. These risk factors were used to construct a nomogram to predict 3-year and 5-year prognosis in adult osteosarcoma. Multivariate cox regression analysis yielded 6 clinicopathological features (age, primary site, tumor size, grade, American Joint Committee on Cancer stage, and surgery) for the prognosis of adult osteosarcoma patients in the training cohort. A nomogram was constructed based on these predictors to assess the prognosis of adult patients with osteosarcoma. Concordance index, receiver operating characteristic and calibration curves analyses also showed satisfactory performance of the nomogram in predicting prognosis. The constructed nomogram is a helpful tool for exactly predicting the prognosis of adult patients with osteosarcoma, which could enable patients to be more accurately managed in clinical practice.
Assuntos
Neoplasias Ósseas , Osteossarcoma , Adolescente , Criança , Humanos , Adulto , Prognóstico , Nomogramas , Osteossarcoma/epidemiologia , Calibragem , Neoplasias Ósseas/epidemiologiaRESUMO
Both canopy gaps (CG) and arbuscular mycorrhizal fungi (AMF) play key roles in seedling establishment and increasing species diversity in forests. The response of AMF to canopy gaps is poorly understood. To assess the long-term effects of canopy gaps on soil AMF community, we sampled soil from plots in a 50-year Cryptomeria japonica (L.f.) D. Don. plantation, located in Lushan Mountain, subtropical China. We analyzed the AMF community, identified through 454 pyrosequencing, in soil and edaphic characteristics. Both richness and diversity of AMF in CG decreased significantly compared to the closed canopy (CC). The differences of the AMF community composition between CG and CC was also significant. The sharp response of the AMF community appears to be largely driven by vegetation transformation. Soil nutrient content also influenced some taxa, e.g., the low availability of phosphorus increased the abundance of Acaulospora. These results demonstrated that the formation of canopy gaps can depress AMF richness and alter the AMF community, which supported the plant investment hypothesis and accentuated the vital role of AMF-plant symbioses in forest management.
RESUMO
The unbridled expansion of bamboo has imposed serious threats on ecosystem processes and functions. Considerable evidence indicates that bamboo invasions can alter plant-available soil nitrogen (N) pools and rates of N cycling, but the consequences of altered N availability for plant growth and community structure have thus far been poorly characterized. The primary soil-accessible N forms for most plants are ammonium (NH4+) and nitrate (NO3-), but plants differ in their ability to use the different N forms, and these differences can be related to their ecological characteristics and drive community structure. In this context, we evaluated the growth response, N uptake and interspecific competition in two subtropical species, Phyllostachys edulis (Carrière) J. Houzeau (Synonym Phyllostachys heterocycla Carrière) and Castanopsis fargesii Franch., dominant species of bamboo and secondary evergreen broad-leaved forests, respectively, under changing N availability in seedlings supplied with different N concentrations and NH4+/NO3- proportions, in vermiculite culture, in a controlled environment. The results show that (i) both species display an NH4+ preference at elevated N concentrations. The growth of P. edulis seedlings was strongly enhanced at increased ratios of NH4+ to NO3- especially at higher N concentrations, but to a much lesser extent in C. fargesii. (ii) NH4+ preference at the level of N uptake in both species was confirmed by the Non-invasive Micro-test Technology and by examining 15N signatures. Phyllostachys edulis had higher NH4+ net fluxes and N concentration under NH4+ treatments than C. fargesii. (iii) NH4+ at higher concentrations caused toxicity in both species as it inhibited root growth and even caused seedling death, but P. edulis had a higher NH4+-tolerance threshold (24 mM) than C. fargesii (16 mM). (iv) When mixed-species cultures were examined in an NH4+-rich medium, the growth of C. fargesii, but not P. edulis, was significantly inhibited compared with growth in monoculture. Therefore, P. edulis exhibited stronger plasticity and adaptation to changing N availability, whereas C. fargesii had low responsiveness and capacity to acclimate to soil N changes. Phyllostachys edulis displayed a significant competitive growth advantage compared with C. fargesii on NH4+-dominated substrates.