https://www.um.edu.mt/library/oar/handle/123456789/139326 2026-04-14T05:41:24Z https://www.um.edu.mt/library/oar/handle/123456789/144850 Title: A preliminary comparative analysis of pesticides residues in illicit and regulated cannabis inflorescence in Malta Abstract: Illicit cannabis consumption presents significant health risks due to the absence of regulatory monitoring in its cultivation, especially with regards to pesticide contamination. In contrast, licensed cannabis produced under regulated frameworks is expected to comply with strict safety standards. This study investigated and compared pesticide residues in illicit cannabis samples seized by law enforcement officers with licensed recreational cannabis inflorescences sourced from Cannabis Associations licensed with the Authority for the Responsible use of Cannabis in Malta. The primary aim was to determine whether illicit cannabis is more likely to contain pesticide contamination. This study thus helped assess public health risks and highlighting the impact of regulatory control. Twenty-four cannabis inflorescence samples were analysed: twelve illicit samples and twelve licensed samples. The methodology employed a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction protocol, followed by instrumental analysis using gas chromatography combined with mass spectrometry (GC-MS) and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). The findings demonstrated that pesticide residues were detected exclusively in illicit cannabis samples, while no pesticide contamination was found in licensed recreational cannabis provided by Cannabis Associations. Two organophosphate pesticides, dichlorvos and chlorpyrifos, were identified across multiple illicit samples. Statistical analysis using Fisher’s exact test confirmed a statistically significant difference in contamination between the two groups (two-sided analysis, p = 0.037). These results highlight the elevated risk associated with illicit cannabis use and emphasise the protective role of regulatory oversight in licensed production. Inhalation of organophosphate pesticide residues may contribute to acute and chronic toxicological effects, presenting a considerable public health concern for consumers of illicit cannabis. These findings support the implementation of strict monitoring frameworks in order to safeguard cannabis quality and strengthen the importance of consumer access to regulated products. Description: M.Sc.(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144451 Title: Analysis of the calls made to the Malta National Poisons Centre Abstract: Background: The Malta National Poisons Centre (MNPC) commenced operations in October 2023, initially serving Healthcare Professionals (HCP) before extending access to the public in May 2024. Poison centres serve as critical epidemiological resources providing essential data on poisoning incidents while offering expert clinical consultation for exposure management. The centre provides telephone consultation services to both HCP and the public for toxicological emergencies. Aim: To analyse the nature and characteristics of all toxicological exposure calls received by the MNPC during its first months of operation, from October 2023 to May 2025, and examine insights regarding poison types and severity in Malta. Methods: A retrospective quantitative analysis was conducted using anonymised call-log data from the MNPC database. The study included all 654 toxicology-related calls meeting inclusion criteria. Data encompassed caller demographics, patient characteristics, exposure circumstances, substance categories, clinical severity using the Poisoning Severity Score (PSS), and documented outcomes. Statistical analysis employed descriptive methods and chi-square tests using SPSS version 29. Results: HCP constituted 76.6% of callers, with 23.4% from the public. Patient gender distribution was balanced (50.8% male, 48.9% female). The largest age groups exposed were 30-39 years (17.4%) and children under 5 years (16.4%). Accidental exposures predominated (40.1%), followed by deliberate exposures (36.2%). Pharmaceutical agents comprised most exposures, with paracetamol-containing analgesics being most frequently reported (15.1%); 59.6% of paracetamol cases involved deliberate poisoning. Most exposures occurred in domestic settings (85.5%) via oral route (84.4%). PSS distribution showed 34.6% asymptomatic, 40.2% minor, 16.8% moderate, 8.3% severe, and 0.2% fatal outcomes. Hospital admission was required in 52.4% of cases, with 60.7% involving clinical toxicologist consultation. Non-Maltese residents comprised 28.3% of cases, with disproportionate representation in workplace exposures (58.3% of occupational cases). Conclusions: The MNPC has successfully integrated into Malta's healthcare system, demonstrating appropriate utilisation and effective outcomes. The epidemiological profile reveals distinct age-related intentionality patterns requiring targeted prevention strategies. Paracetamol prominence in deliberate exposures and significant non-Maltese representation in occupational exposures indicate specific risk factors requiring public health intervention. These findings provide essential baseline data for evidence-based prevention strategies and clinical protocol optimisation. Description: M.Sc.(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/140656 Title: Cannabidiol (CBD) in cannabis-infused edibles in Malta Abstract: After Malta’s legalisation for the recreational use of cannabis in 2021, the local market has seen an increase in the accessibility of edibles in cannabis shops. While the level of tetrahydrocannabinol (THC) is permitted if it does not exceed 0.2 percent, there is no set limit on the amount of cannabidiol (CBD) permitted in recreational products. The rising demand, has led to this in-depth investigation, to ensure consumer safety and promote transparency, in the labelling of CBD edibles. Thus, this study aimed mainly to investigate the presence or absence of CBD in edibles, and to then compare it with the labelling of the samples. The technique used to detect CBD and any other additional components in edibles, was gas chromatography-mass spectrometry (GC/MS). Samples of six different edibles (gummies, chocolates, sleep candies, a muffin, and cookies) were bought from a local shop. The samples underwent several preparatory procedures, including crushing, methanol dilution, vortexing, sonication, and filtration, along with supplementary steps of centrifugation, dilution, and vortexing prior to the filtration of gelatinous edibles (sample 6). These preparatory procedures were done to ensure that samples were well prepared, before the analysis by the GC/MS. The analysis uncovered significant inconsistencies in the labelling precision of CBD edibles. While four of the six samples contained CBD, Sample 2 was mislabelled, as it contained CBDA instead of CBD due to incomplete decarboxylation, highlighting misleading labelling practices. Sample 3 was particularly problematic due to its packaging, which failed to disclose the presence of CBD and Δ9-THCH, and omitted caffeine, thereby raising concerns regarding regulatory compliance. Similarly, Sample 5 omitted both CBN and CBD from its ingredient list, implying the potential presence of CBD, indirectly through the labelled “organic hemp extract”. Caffeine was also detected in sample 4 without appropriate disclosure. Moreover, sample 4 was marketed by sellers as a CBD product, but it lacked CBD. These findings underscore a deficiency in transparency and the possible dangers linked to mislabelling. Samples 1 and 6 exhibited precise CBD labelling, signifying their reliability. This study emphasises the necessity for more stringent regulations and standardised practices within the commercial cannabis sector, particularly concerning accurate labelling. This research reveals significant consumer safety concerns, highlighting the need for regulatory measures to ensure quality and transparency in products, to ultimately protect the public’s health. Description: B.Sc. (Hons)(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/140568 Title: Reprogramming regulatory T cells to effector T cells for enhanced antitumour responses : a study on non-small cell lung carcinoma cell lines Abstract: Introduction: Current therapeutic approaches for lung cancer including surgery, chemotherapy, radiotherapy, and immunotherapy are often limited by significant side effects and suboptimal long-term outcomes, highlighting the urgent need for innovative strategies, particularly within the field of immunotherapy. Regulatory T cells (Tregs) play an essential role in maintaining immunological homeostasis and preventing autoimmunity, however, their immunosuppressive properties can also hinder effective antitumour responses by promoting an immunosuppressive tumour microenvironment. This effect is especially pronounced in non-small cell lung cancer (NSCLC), where increased Treg infiltration is strongly associated with poorer prognosis and decreased treatment efficacy. Given their functional plasticity under inflammatory conditions, recent research has turned to the potential of reprogramming Tregs into proinflammatory effector-like cells—such as Th1-like cells—capable of producing cytokines that support antitumour immunity and counteract tumour-mediated immune suppression. Aim: This research project aims to investigate the potential reprogramming of Tregs into Th1-like effector cells by assessing both their phenotypic and functional shift. Specifically, the study evaluates whether Tregs exposed to pro-inflammatory conditions can adopt Th1-like cells characteristics, and whether these reprogrammed cells exhibit anti-tumour activity specifically on NSCLC. Method: The CellXVivo Human Treg Cell Differentiation Kit was used to polarise CD4⁺ T cells into Tregs after they were isolated from human peripheral blood mononuclear cells, via negative magnetic selection. In order to encourage Treg reprogramming toward a Th1-like phenotype, treatment with high and low doses of IL-12 was done. After treatment, H460, a NSCLC cell line, were treated with different concentrations of conditioned media in order to evaluate the supposed anti-tumour functions of the reprogrammed Tregs, using CFSE-based proliferation assays. Results: Phenotypic analysis revealed that in some cases, Tregs expressing FOXP3 were not generated in the first place, which could be attributed to donor-to-donor heterogeneity, and thus, the direct impact of IL-12 on the phenotype of Tregs was inconclusive. Treated Treg also retained high CD25 expression typical of Treg. The conditioned media from IL-12-treated Tregs at concentration 80% reduced H460 proliferation relative to cells cultured in complete RPMI media, however unexpectedly this reduction was not as much as those cultured in untreated Treg conditioned media, suggesting IL-12 alone may be insufficient to cause the treated CD4+ cells to acquire effective effector cytokine production with anti-tumourigenic effects. Conclusion: While IL-12 has some influence on Treg plasticity, the results suggest that it is insufficient on its own to drive complete reprogramming into Th1-like effector cells, as CD25 expression was still retained and the suppressive activity of the conditioned media from IL-12-treated Tregs was not as significant as the conditioned media of untreated Tregs. These results underscore the complexity of Treg plasticity and highlight the need for additional signals to effectively achieve Tregs and convert these cells into functionally potent anti-tumour effector T cells with anti-tumourigenic properties Description: B.Sc. (Hons)(Melit.) 2025-01-01T00:00:00Z