https://www.um.edu.mt/library/oar/handle/123456789/9259 Sat, 04 Apr 2026 03:16:22 GMT 2026-04-04T03:16:22Z https://www.um.edu.mt/library/oar/handle/123456789/9307 Title: Optimization and validation of a flow cytometric method for the measurement of ZAP-70 in B-cell Chronic Lymphocytic Leukemia Abstract: B-cell Chronic Lymphocytic Leukemia (B-CLL) is a clonal lymphoproliferative disorder which exhibits clinical heterogeneity (Bosch, et al., 2006). A prognostic marker for B-CLL is Zeta-chain-associated protein kinase-70 (ZAP-70) which is an intracellular protein. When expressed in high levels in B-CLL cells, ZAP-70 implicates a poor prognostic outcome (Shults, Miller, Davis, Flye, Hobbs, & Stelzer, 2006). The aim of this study was to introduce ZAP-70 as part of the diagnostic and prognostic services in Malta by establishing a method for the determination of ZAP-70 in BCLL patients. A technically validated method of sample preparation used at the Royal Marsden Hospital, Sutton UK was optimized for use within the Haematology Laboratory, Pathology Department at Mater Dei Hospital. This method was then compared to two other methods of sample preparation to determine the best method to use at the Haematology laboratory for ZAP-70 testing. The Percentage Positivity (PP) and the Mean Fluorescent Intensity (MFI) were determined for each sample and the best approach was chosen to report ZAP-70 positivity. Statistical Analysis of the three methods showed that our optimized method, cytoplasmic to membrane staining (C&M) discriminates better between ZAP-70 positive and negative populations. Moreover, false positives were reported with the MFI approach and hence, the PP approach was chosen to identify ZAP-70 positivity. This study established the best method for ZAP-70 testing to be applied at the Haematology Laboratory, Mater Dei Hospital. This will improve the diagnostic protocol of B-CLL patients, which consequently will allow better patient management. Description: B.SC.(HONS)BIOMED.SCI. Tue, 01 Jan 2013 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/9307 2013-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/9301 Title: Functional characterisation of the survival motor neuron complex member Gemin5 Abstract: Spinal Muscular Atrophy (SMA) is a neurodegenerative disease characterized by loss of motor neurons as a result of a deficiency of the survival of motor neuron (SMN) gene. The SMN gene encodes a protein, the SMN protein, which exists in the cell as part of a large complex where it associates with at least 9 other proteins, which together play a role in the assembly of different classes of ribonucleoproteins (RNPs) in RNA processing. The SMN gene is highly conserved in evolution and is detected in various animals, leading to the development of animal models to model human diseases like SMA, in an attempt to understand its pathogenesis in humans. Due to its rapid generation time and the vast choice of genetic tools which can be used, the fruit fly, Drosophila melanogaster, has been widely used to model SMA amongst other neurodegenerative diseases, for the correct interpretation of the phenotypes produced as a result of such disease. In this study, Drosophila was used for the functional assessment of Gemin5, one of the peripheral components of the SMN complex. A role in larval development as well as in RNP processing has been observed in the ortholog of human Gemin5, termed Rigor Mortis (Rig). Further functional assessment of Gemin5 in Drosophila was carried out by observing phenotypes produced by Gemin5 specific loss-of-function mutants as well as Gemin5 knockdown via larval mobility assays and adult viability assays respectively. Results demonstrated that that total removal of gemin5 brings about lethality at an early stage of development, suggesting that Gemin5 activity is essential for regular development of flies. It was also concluded, that Gemin5 is required in large quantities for appropriate muscle operation. Such findings compliment a possible function of Gemi Clearly, additional studies should provide insights into the significance of Gemin5 and its functions, as well as its contribution within the SMN complex, with the hope of clarifying the molecular mechanisms underlying SMA. Description: B.SC.(HONS)BIOMED.SCI. Tue, 01 Jan 2013 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/9301 2013-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/9260 Title: Diagnostic accuracy in the subclassification of non-small cell lung carcinomas in bronchial cytology specimens Abstract: Lung cancer is the most common cancer and also a leading cause of cancerrelated mortality worldwide. Accurate classification of non-small cell lung cancer (NSCLC) into squamous cell carcinoma (SCC) and adenocarcinoma (ACA) is becoming increasingly important with the advent of new targeted therapeutic agents. The reliability of the cytology diagnostic service in NSCLC classification has not been locally assessed to date. This study thus aimed to assess cytological diagnostic accuracy and determine the significance of several cytomorphological features in NSCLC classification. Residual material from bronchial lavage specimens received between June 2011 and December 2012, and diagnosed as ACA or SCC, was used for cell block preparation, histological processing and Haematoxylin and Eosin (H&E) staining. Cell blocks having adequate cellularity on H&E were selected for immunohistochemical (IHC) staining, used as the reference method for classification. Twenty (20) further cases diagnosed during 2011 and 2012 and having IHC results were retrospectively retrieved, amounting to a total of 48 cases. Corresponding Papanicolau stained slides were examined for a variety of cytomorphological features by two independent observers. Upon comparison of cytology and IHC results, inter-observer agreement was found to be substantial (κ=0.705) and the overall cytological diagnostic accuracy was 88.9%. The most significant cytomorphological features in distinguishing SCC cases were found to be orangeophilic cytoplasm and spindle cells; for ACA the presence of foamy cytoplasm was most significant. Diagnostic accuracy of NSCLC sub-typing by cytomorphology alone is high, especially in SCC cases; ancillary techniques such as IHC retain their importance in sub-optimal cases. Description: B.SC.(HONS)BIOMED.SCI. Tue, 01 Jan 2013 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/9260 2013-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/9258 Title: Determining the frequency of human platelet antigen-1 polymorphisms in the Maltese population Abstract: Platelets bear the fibrinogen receptor αIIbβ3, an integrin which is required for normal haemostasis. The human platelet antigen 1 (HPA-1) system is located at residue 33 of the αIIb component of this integrin. An amino acid change from a leucine (Leu) to a proline (Pro) occurs at this position due to a single nucleotide substitution (SNP) of a T to a C at base 196 of the ITGB3 gene coding for the αIIb protein. This results in the HPA-1a (Leu33) and HPA-1b (Pro33) alloantigens, which constitute the HPA-1 system. In the sample population studied which represented the Maltese population, the HPA-1b allele frequency was found to be 15.6 % and the HPA-1a allele frequency was found to be 84.4 %. The presence of the HPA-1b allele has been associated with myocardial infarction (MI), whilst the presence of the HPA-1a allele has been associated with autism. In rare cases in pregnancy or a blood transfusion, platelet incompatibility due to the HPA-1a and HPA-1b antigens occurs, resulting in alloantibody production against foreign HPA-1 antigens. Conditions associated with platelet incompatibility include neonatal alloimmune thrombocytopenia (NAIT), complications of NAIT, platelet transfusion refractoriness, post-transfusion purpura (PTP), and recurrent miscarriages. Thus, since the HPA-1a and HPA-1b allele frequencies of the Maltese population are similar to other European Caucasian population frequencies and African population frequencies, they may indicate similar polymorphism-associated diseases which may be studied alongside this polymorphism in the future. Description: B.SC.(HONS)BIOMED.SCI. Tue, 01 Jan 2013 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/9258 2013-01-01T00:00:00Z