Thrombotic Features as the Primary Cause of SARS-CoV-2 Related Acute Abdomen in Children.

OBJECTIVES: We performed a retrospective case control study to evaluate the histological characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive pediatric patients undergoing laparoscopic exploration for acute abdomen symptoms. To our knowledge this is the first study that analyzes histopathological characteristics of abdominal tissues in SARS-CoV-2 children. STUDY DESIGN: We enrolled 8 multisystem inflammatory syndrome in children (MIS-C) patients and 4 SARS-CoV-2 positive patients who underwent intestinal resection versus 36 control appendectomies from 2 pediatric tertiary referral centers between March 2020 and July 2021. Surgical resection samples were evaluated on several histological sections focusing on general inflammatory pattern and degree of inflammation. Peculiar histological features (endotheliitis and vascular thrombosis) were semi-quantitatively scored respectively in capillary, veins, and arteries. RESULTS: All SARS-CoV-2 related surgical samples showed thrombotic patterns. Those patterns were significantly less frequent in SARS-CoV-2 negative appendectomies ( P = 0.004). The semi-quantitative score of thrombosis was significantly higher ( P = 0.002) in patients with SARS-CoV-2 related procedures. CONCLUSIONS: Our results showed that SARS-CoV-2 can cause thrombotic damage in abdominal tissues both in the acute phase of the infection (SARS-CoV-2 related appendectomies) and secondary to cytokine storm (MIS-C).

Canakinumab in systemic juvenile idiopathic arthritis: real-world data from a retrospective Italian cohort.

OBJECTIVE: The objective of this study was to use real-world data to evaluate the effectiveness and safety of canakinumab in Italian patients with systemic JIA (sJIA). METHODS: A retrospective multicentre study of children with sJIA was performed. Clinical features, laboratory parameters and adverse events were collected at baseline, and 6 and 12 months after starting canakinumab. The primary outcome measure of effectiveness was clinically inactive disease (CID) off glucocorticoids (GCs) treatment at 6 months. RESULTS: A total of 80 children from 15 Italian centres were analysed. Of the 12 patients who started canakinumab in CID while receiving anakinra, all maintained CID. Of the 68 with active disease at baseline, 57.4% achieved CID off GCs at 6 months and 63.8% at 12 months. In univariate analysis, the variables significantly related to non-response were number of active joints (NAJs) ≥5, history of macrophage activation syndrome (MAS) and disease duration. Multivariate analysis confirmed the association between non-response and NAJs ≥5 [odds ratio (OR) 6.37 (95% CI: 1.69, 24.02), P = 0.006] and between non-response and history of MAS [OR 3.53 (95% CI: 1.06, 11.70), P = 0.039]. No serious adverse events were recorded in this series. There were two cases of MAS during canakinumab, leading to a rate of 2.9 episodes per 100 patient years. CONCLUSION: We have confirmed, using real-world data, the efficacy of canakinumab in sJIA in a multicentric cohort. History of MAS and higher NAJ were associated with lower probability of achieving CID.

Solanum linnaeanum Leaves: Chemical Profiling of VOCs and Effects on Seed Germination and Early Growth of Monocots and Dicots.

Some Solanaceae plants are a rich source of sesquiterpenoid phytoalexins with allelopathic potential. Powder and aqueous extract obtained from the leaves of Solanum linnaeanum Hepper & P.M.L. Jaeger were used to treat the seeds of three target species (Lolium multiflorum Lam., Sinapis alba L. and Trifolium incarnatum L.). Both matrices were evaluated along with untreated controls to determine their toxicity on germination and seedling growth. The results revealed that the pre-emergence treatments were able to be very effective against all three species in the filter paper test by inhibiting the germination up to 100 %. The effectiveness was reduced by the interaction with soil. Despite this, significant data were obtained, albeit different according to the applied matrix. In general, L. multiflorum was the most sensitive to both the action of the leaf powder and aqueous extract while S. alba was found to be the most resistant to powder activity and T. incarnatum had the strongest response to the extract. For the first time, SPME-GC/MS technique was used to characterize the volatile chemical profile of S. linnaeanum leaves. The analyses highlighted the presence of different classes of compounds including terpenoids and sesquiterpenoids potentially useful in the fight against noxious plants both in natural and cultivated ecosystems.

The multifaceted presentation of chronic recurrent multifocal osteomyelitis: a series of 486 cases from the Eurofever international registry.

OBJECTIVES: Chronic non-bacterial osteomyelitis (CNO) or chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder characterized by sterile bone osteolytic lesions. The aim of this study was to evaluate the demographic data and clinical, instrumental and therapeutic features at baseline in a large series of CNO/CRMO patients enrolled in the Eurofever registry. METHODS: A web-based registry collected retrospective data on patients affected by CRMO/CNO. Both paediatric and adult centres were involved. RESULTS: Complete baseline information on 486 patients was available (176 male, 310 female). The mean age of onset was 9.9 years. Adult onset (>18 years of age) was observed in 31 (6.3%) patients. The mean time from disease onset to final diagnosis was 1 year (range 0-15). MRI was performed at baseline in 426 patients (88%), revealing a mean number of 4.1 lesions. More frequent manifestations not directly related to bone involvement were myalgia (12%), mucocutaneous manifestations (5% acne, 5% palmoplantar pustulosis, 4% psoriasis, 3% papulopustular lesions, 2% urticarial rash) and gastrointestinal symptoms (8%). A total of 361 patients have been treated with NSAIDs, 112 with glucocorticoids, 61 with bisphosphonates, 58 with MTX, 47 with SSZ, 26 with anti-TNF and 4 with anakinra, with a variable response. CONCLUSION: This is the largest reported case series of CNO patients, showing that the range of associated clinical manifestations is rather heterogeneous. The study confirms that the disease usually presents with an early teenage onset, but it may also occur in adults, even in the absence of mucocutaneous manifestations.

Quantifying the Accuracy of Digital Hemispherical Photography for Leaf Area Index Estimates on Broad-Leaved Tree Species.

Digital hemispherical photography (DHP) has been widely used to estimate leaf area index (LAI) in forestry. Despite the advancement in the processing of hemispherical images with dedicated tools, several steps are still manual and thus easily affected by user's experience and sensibility. The purpose of this study was to quantify the impact of user's subjectivity on DHP LAI estimates for broad-leaved woody canopies using the software Can-Eye. Following the ISO 5725 protocol, we quantified the repeatability and reproducibility of the method, thus defining its precision for a wide range of broad-leaved canopies markedly differing for their structure. To get a complete evaluation of the method accuracy, we also quantified its trueness using artificial canopy images with known canopy cover. Moreover, the effect of the segmentation method was analysed. The best results for precision (restrained limits of repeatability and reproducibility) were obtained for high LAI values (>5) with limits corresponding to a variation of 22% in the estimated LAI values. Poorer results were obtained for medium and low LAI values, with a variation of the estimated LAI values that exceeded the 40%. Regardless of the LAI range explored, satisfactory results were achieved for trees in row-structured plantations (limits almost equal to the 30% of the estimated LAI). Satisfactory results were achieved for trueness, regardless of the canopy structure. The paired t-test revealed that the effect of the segmentation method on LAI estimates was significant. Despite a non-negligible user effect, the accuracy metrics for DHP are consistent with those determined for other indirect methods for LAI estimates, confirming the overall reliability of DHP in broad-leaved woody canopies.

Estimating Leaf Area Index (LAI) in Vineyards Using the PocketLAI Smart-App.

Estimating leaf area index (LAI) of Vitis vinifera using indirect methods involves some critical issues, related to its discontinuous and non-homogeneous canopy. This study evaluates the smart app PocketLAI and hemispherical photography in vineyards against destructive LAI measurements. Data were collected during six surveys in an experimental site characterized by a high level of heterogeneity among plants, allowing us to explore a wide range of LAI values. During the last survey, the possibility to combine remote sensing data and in-situ PocketLAI estimates (smart scouting) was evaluated. Results showed a good agreement between PocketLAI data and direct measurements, especially for LAI ranging from 0.13 to 1.41 (R² = 0.94, RRMSE = 17.27%), whereas the accuracy decreased when an outlying value (vineyard LAI = 2.84) was included (R² = 0.77, RRMSE = 43.00%), due to the saturation effect in case of very dense canopies arising from lack of green pruning. The hemispherical photography showed very high values of R², even in presence of the outlying value (R² = 0.94), although it showed a marked and quite constant overestimation error (RRMSE = 99.46%), suggesting the need to introduce a correction factor specific for vineyards. During the smart scouting, PocketLAI showed its reliability to monitor the spatial-temporal variability of vine vigor in cordon-trained systems, and showed a potential for a wide range of applications, also in combination with remote sensing.

Adalimumab for juvenile idiopathic arthritis-associated uveitis.

PURPOSE: To assess the long-term outcomes and complications of patients with uveitis from juvenile idiopathic arthritis (JIA) treated with adalimumab. METHODS: Prospective interventional case series. All patients who underwent treatment with adalimumab for JIA and anterior uveitis were prospectively included in the study. The anterior chamber inflammation was evaluated according to the Standardization of Uveitis Nomenclature criteria. RESULTS: Twenty-one patients (16 females, five males, 38 eyes) were included in the study. Mean age of patients at referral was 11.1 ± 3.8 (5-17) years. Before initiation of treatment, mean duration of arthritis was 7.0 ± 5.5 (median, 6) months, mean duration of uveitis was 7.0 ± 4.4 (median, 7) months. Oligoarticular arthritis was present in 15 cases (71 %), polyarticular arthritis in six cases (28 %). After a mean follow-up of 18.2 ± 7.7 (9-41) months, resolution of anterior chamber inflammation was obtained in 29/38 eyes (76 %). The anterior uveitis flare rate during the 12 months prior to enrollment was 1.6 ± 0.4/year, and was reduced during adalimumab treatment to 0.7 ± 0.3/year (p<0.001). A significant decrease of the number of relapses/month was present after onset of treatment with adalimumab (0.18 ± 0.2 before versus 0.02 ± 0.1 after treatment onset, p<0.001). No significant correlation was found between relapse number and age, sex, type of JIA and doses of previous steroid treatment (p>0.05). CONCLUSION: Adalimumab showed to be effective and relatively safe for treatment of JIA-associated uveitis.

Never Say Never: Successful Extracorporeal Cardiopulmonary Resuscitation (ECPR) Following A Prolonged Out-of-Hospital Cardiac Arrest Due to Spontaneous Coronary Artery Dissection.

Introduction: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) may be a life-saving rescue therapy for patients with severe cardiac disease of any origin and circulatory failure. Data in the literature have demonstrated that the use of advanced mechanical circulation has resulted in improvements in both survival and quality of life; despite this, cardiogenic shock and refractory cardiac arrest remain conditions with high mortality. Opportune identification of patients who can benefit from it may improve outcomes. However, the shortage of guidelines on indications often results in a high mortality rate and poor outcome. Due to ethical issues, randomised controlled studies with VA-ECMO have not been conducted so no recommended evidence-based guidelines exist for VA-ECMO patient-selection criteria. Therefore, the indications depend only on expert opinion after reviewing the literature. Case description: We report the case of a young female patient who presented with an out-of-hospital cardiac arrest (OHCA) due to spontaneous coronary dissection. She was treated with extracorporeal cardiopulmonary resuscitation (ECPR) with excellent results in terms of short and long-term survival, and neurological outcome. This was despite the presence of several clinical and laboratory negative prognostic factors on the basis of the current literature, and the lack of general consensus among the relevant medical personnel. Conclusion: We were able to explain the favourable outcome only on the basis of clinical data. We can conclude that the availability of advanced resources in the area (timeliness of the rescues, quality of the resuscitation, an advanced haemodynamic management centre nearby) has contributed to determining the complete clinical and neurological recovery of the patient. LEARNING POINTS: Extracorporeal cardiopulmonary resuscitation to rescue patients with cardiac arrest refractory to conventional cardiopulmonary resuscitation could represent a life-saving technique in carefully selected patients.Refractory out-of-hospital cardiac arrest with evolution to a non-shockable rhythm and severe lactic acidosis are conditions that should not rule out ECPR.Evidence-based selection of ECPR patients remains challenging, but it could be considered as a therapeutic option in dedicated specialised centres.

Stenotrophomonas rhizophila Ep2.2 inhibits growth of Botrytis cinerea through the emission of volatile organic compounds, restricts leaf infection and primes defense genes.

The bacterium Stenotrophomonas rhizophila is known to be beneficial for plants and has been frequently isolated from the rhizosphere of crops. In the present work, we isolated from the phyllosphere of an ornamental plant an epiphytic strain of S. rhizophila that we named Ep2.2 and investigated its possible application in crop protection. Compared to S. maltophilia LMG 958, a well-known plant beneficial species which behaves as opportunistic human pathogen, S. rhizophila Ep2.2 showed distinctive features, such as different motility, a generally reduced capacity to use carbon sources, a greater sensitivity to fusidic acid and potassium tellurite, and the inability to grow at the human body temperature. S. rhizophila Ep2.2 was able to inhibit in vitro growth of the plant pathogenic fungi Alternaria alternata and Botrytis cinerea through the emission of volatile compounds. Simultaneous PTR-MS and GC-MS analyses revealed the emission, by S. rhizophila Ep2.2, of volatile organic compounds (VOCs) with well-documented antifungal activity, such as furans, sulphur-containing compounds and terpenes. When sprayed on tomato leaves and plants, S. rhizophila Ep2.2 was able to restrict B. cinerea infection and to prime the expression of Pti5, GluA and PR1 plant defense genes.

Advances in the Diagnosis and Treatment of Enthesitis-Related Arthritis.

Enthesitis-related arthritis (ERA) represents 5-30% of all cases of juvenile idiopathic arthritis (JIA) and belongs to the spectrum of the disorders included in the group of juvenile spondyloarthritis. In the last decade, there have been considerable advances in the classification, diagnosis, monitoring, and treatment of ERA. New provisional criteria for ERA have been recently proposed by the Paediatric Rheumatology INternational Trials Organisation, as part of a wider revision of the International League of Associations for Rheumatology criteria for JIA. The increased use of magnetic resonance imaging has shown that a high proportion of patients with ERA present a subclinical axial disease. Diverse instruments can be used to assess the disease activity of ERA. The therapeutic recommendations for ERA are comparable to those applied to other non-systemic JIA categories, unless axial disease and/or enthesitis are present. In such cases, the early use of a TNF-alpha inhibitor is recommended. Novel treatment agents are promising, including IL-17/IL-23 or JAK/STAT pathways blockers.

Selective phytotoxic activity of eugenol towards monocot and dicot target species.

Eugenol is a phenylpropanoid with a wide range of documented biological activities. Due to its versatility, it is incorporated as an active ingredient in numerous products including those intended for agriculture. We assessed the phytotoxic potential of the vapor phase of eugenol tested at 2 and 20 µl against the seeds of five weeds, both monocots and dicots. The lowest dose was able to prevent the germination of Echinochloa oryzoides, while the highest amount fully inhibited the germination of Lolium multiflorum and Sinapis alba. Trifolium incarnatum and Vicia sativa were significantly controlled only by the effect of 20 µl of eugenol. Their germination was reduced by 58.6% and 62.1%, respectively, with values of the seedling vigour index lower by more than 80% than those of the controls. It is reasonable to think of eugenol as a lead molecule in the development of new bioformulates useful in integrated weed management programs.

Off-label use of canakinumab in pediatric rheumatology and rare diseases.

Since the first success of interleukin-1 blockade in cryopyrin-associated periodic syndrome, the use of interleukin-1 inhibitors has expanded to other disorders, including off-label indications. In particular, canakinumab has been employed in an off-label fashion in several diseases such as rare monogenic autoinflammatory diseases and multifactorial autoinflammatory diseases, disclosing an excellent efficacy and good safety profile in pediatric patients unresponsive to standards of care. In addition, hyperferritinemic syndromes and complex disorders, as well as Kawasaki disease, uveitis, and other pediatric rare disorders, represent additional areas where canakinumab efficacy is worth exploring. Altogether, the results summarized below are of paramount importance in pediatric patients where a considerable proportion of treatments are prescribed off-label. This review focuses on the off-label use of canakinumab in pediatric patients affected by systemic immune-mediated diseases.

The environmental impacts of different organic rice management in Italy considering different productive scenarios.

Rice cultivation has a key role in food security worldwide; on the other hand, it has a high potential impact on the environment and human health, mainly due to the extensive pesticides use and greenhouse gas emissions caused by flooded cultivation. In Italy, the rice sector based mainly on high-input monoculture. The transition toward organic agriculture can improve the environmental performance of rice farming according to the actual European sustainable food production strategy. Through LCA methodology, the study aims to evaluate the variability of the environmental impacts and the mitigation potential of four management strategies suitable for organic rice production in North Italy and two production potential levels observed during three-year monitoring on 10 farms in the study area. The LCA analysis includes the wide range of agronomic realities that characterise this farming system, assessing the variation in environmental performance by exploring eight plausible and possible scenarios for organic rice. Results suggest a considerable potential of organic rice production to mitigate its impact on natural resources, depending on the chosen agricultural practices. In particular, six LCA indicators showed a potential of reduction over 40 %, shifting from the worst-performing management to the better one. Finally, the large variability of climate change impacts assessed, both in this study and in literature, is due to the corresponding existing large variability in terms of yield and available patterns of agricultural practices. Today the farmers could reach acceptable yield values thanks to more efficient management than in the past. The acknowledgement for that performances relates to the development of the farmers' know-how and to the productive improvement connected to the long-term processes which characterise the organic systems (e.g. generation of soil fertility based on biological fertility and stable humus components; lowering of weeds pressure through the gradual introduction of other crops in rotation).

Distinctive Phenotype of Multisystem Inflammatory Syndrome in Children Associated with SARS-CoV-2 According to Patients' Age: A Monocentric Experience.

Background: Multisystem inflammatory syndrome in children (MIS-C) is a disease temporally related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and it is characterized by fever, conjunctival injections, rash, gastrointestinal symptoms, and cardiovascular complications. We evaluated the clinical presentation, laboratory findings, imaging features, therapeutic interventions, and hospital course of a monocentric cohort, and we analyzed these findings according to two age groups. Methods: Patients with MIS-C admitted to a Tertiary Care Pediatric Hospital from November 2020 to November 2021 were considered for the enrollment. Results: Overall, 35 consecutive patients were included. Most of the children did not require intensive care unit at the admission. The clinical presentation of MIS-C slightly differs according to age groups. Mucocutaneus involvement was more frequent in younger patients, while abdominal symptoms were present in 54% of patients aged less than 5 years and in 95% of patients aged more than 5 years (p < 0.05). In addition, the number of cases with troponin above the normal reference value was significantly higher in older patients (77%) compared to younger cases (15%) (p < 0.01). Conclusions: MIS-C is a new emerging condition and represents a challenge to pediatricians due to the severity of presentation. Further studies to better characterize the long-term outcome of MIS-C patients are mandatory.

Etanercept as a successful therapy in autoinflammatory syndrome related to TRNT1 mutations: a case-based review.

Mutations in the gene encoding tRNA nucleotidyltransferase 1 (TRNT1) are associated with heterogeneous phenotypes and multisystem involvement of variable severity and progression. Immunodeficiency and inflammation are recurrent-associated features. The use of cytokine inhibitors in suppressing the inflammatory phenotype has been recently reported, with a 3-year follow-up for patients treated with Etanercept. We report on two unrelated patients sharing the same clinical condition, who had been referred to our Pediatric Rheumatology Unit because of recurrent fever associated with cutaneous lesions and increased levels of inflammatory markers since their first months of life. Whole exome sequencing allowed to identify compound heterozygosity for functionally relevant variants in TRNT1 as the only molecular event shared by the two patients. Both patients have been treated with Etanercept during 11 years, documenting normalization of inflammatory indexes and resolution of recurrent fever and associated symptoms. This is the longest follow-up assessment of Etanercept treatment in patients with TRNT1 mutations. Our findings confirm efficacy and safety of the treatment. Key Points • Mutations in TRNT1 have been associated with phenotypic heterogeneity. • We report on two patients with early-onset autoinflammatory syndrome. • Whole exome sequencing led to reveal compound heterozygosity for two variants in TRNT1 in both patients. • The patients were successfully treated with Etanercept for more than 10 years, the longest follow-up described in literature.

Multisystem inflammatory syndrome in children. An emerging clinical challenge for pediatric surgeons in the COVID 19 era.

BACKGROUND/PURPOSE: Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening condition occurring 2-6 weeks after Coronavirus disease 2019 (COVID-19) in previously healthy children and adolescents, characterized by clinical and laboratory evidence of multiorgan inflammation. We reported the case of a 6-year-old child presented with acute abdomen and then diagnosed with MIS-C. In addition, to better portray this new entity, we performed a systematic review of MIS-C gastrointestinal features and particularly on those mimicking surgical emergencies. METHODS: We described the clinical presentation, the diagnostic approach and the therapeutic outcomes of our MIS-C patient. Parallel to this, we conducted a systematic literature search using Google Scholar, PubMed, EMBASE, Scopus, focusing on gastrointestinal MIS-C. RESULTS: Our patient was initially assessed by the surgical team due to his query acute abdomen. Following the diagnosis of MIS-C with myocarditis, intravenous methylprednisolone (2 mg/Kg/day) and intravenous immunoglobulins (2 gr/Kg single infusion) were promptly started, leading to clinical improvement. According to our literature search, patients with MIS-C have a high rate of severe abdominal symptoms resembling surgical emergencies (appendicitis, obstruction, etc.) and a not negligible number of those patients have been surgically explored with variable findings. CONCLUSIONS: We encourage pediatric surgeons in the upcoming months of COVID-19 pandemic to evaluate myocardial function prior to surgical abdominal exploration. In children with query acute abdomen, MIS-C should be promptly ruled out in order to avoid unnecessary surgeries that could worsen the already frail outcome of this new syndrome. Nevertheless, it should be considered that MIS-C might well encompass complications (e.g. appendicitis, segmental intestinal ischemia) which need swift surgical treatment.

Fibrodysplasia Ossificans Progressiva: A Challenging Diagnosis.

Fibrodysplasia ossificans progressiva (FOP) is an ultrarare genetic condition characterized by extraskeletal bone formation. Most of the musculoskeletal characteristics of FOP are related to dysregulated chondrogenesis, with heterotopic ossification being the most typical feature. Activating mutations of activin receptor A type I (ACVR1), a bone morphogenetic protein (BMP) type I receptor, are responsible for the skeletal and nonskeletal features. The clinical phenotype is always consistent, with congenital bilateral hallux valgus malformation and early-onset heterotopic ossification occurring spontaneously or, more frequently, precipitated by trauma. Painful, recurrent soft-tissue swellings (flare-ups) precede localized heterotopic ossification that can occur at any location, typically affecting regions near the axial skeleton and later progressing to the appendicular bones. A diagnosis of FOP is suspected in a proband presenting with hallux valgus malformation, heterotopic ossification, and confirmed by the identification of a heterozygous pathogenic variant in the ACVR1/ALK2 gene. Avoiding unnecessary surgical procedures, prescribing prophylactic corticosteroids, preventing falls, and using protective headgear represent essential interventions for care management. Different classes of medications to contain acute inflammation flare-ups have been proposed, with high dose corticosteroids and nonsteroidal anti-inflammatory drugs usually utilized. Here, we report on two FOP patients, with typical clinical features summarizing the principal aspects of FOP, and we aim to provide comprehensive information outlining some unusual findings, possibly contributing to FOP's definition and management.

Anterior Segment-Optical Coherence Tomography features in Blau syndrome.

Blau syndrome (BS) is a rare granulomatous auto-inflammatory disease, characterized by the classic clinical triad of joints, skin and ocular involvements. Ocular manifestation usually consists in a bilateral insidious chronic anterior uveitis with a potential evolution to panuveitis. We describe the case of two siblings, an 8-years old female and a 5-years old male, with a diagnosis of BS, evaluated by Anterior Segment-Optical Coherence Tomography (AS-OCT). In the female patient, slit-lamp examination revealed bilateral anterior granulomatous uveitis and inflammatory sequelae. AS-OCT revealed high intensity reflective layers in the anterior cornea, hyperreflective dots both in the aqueous humor and in the posterior corneal surface. In the male, no signs of inflammation were detected both on slit-lamp examination and AS-OCT scans. AS-OCT is a valuable, non-invasive tool that could improve the diagnosis of ocular involvement, better characterize and follow-up corneal alterations and anterior segment features in pediatric patients with BS.

Potential Role of Lolium multiflorum Lam. in the Management of Rice Weeds.

The phytotoxic relationships between crops and weeds can cover a role in weed management, reducing the use of chemical herbicides. Starting from the organic farmers' experience, the study aimed to define the inhibitory action of Lolium multiflorum Lam., used as a cover crop before rice sowing, against Echinochloa oryzoides (Ard.) Fritsch, one of the main rice weeds. In vitro 7-day assays were carried out in Petri dishes to compare the effect of different L. multiflorum Lam. parts, in the form of aqueous extract or powder, on the seed germination and seedling growth of Oryza sativa L. and E. oryzoides and to verify the hypothesis of a higher susceptibility of the weed. The total polyphenolic content, as the potential source of allelochemicals, in the L. multiflorum parts was measured. The results showed that both species suffer the phytotoxic action of L. multiflorum, but a more marked effect against E. oryzoides was recorded. In according with the polyphenol quantities, stem and inflorescence extracts showed the more significant species-specific inhibition. In all assays, the weed showed a stronger reduction in the root length and seedling vigor index, and, in some cases, also in the germination percentage and shoot length compared to rice.