Thumbnail Image

Thesis

Browse

2017 - 201912020 - 20221
Reset filters
Subject: Veterinary Pathology × Start date: 2010 × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ThesisItemOpen Access
    HISTOMORPHOLOGICAL, IMMUNOHISTOCHEMICAL AND MOLECULAR STUDIES ON DESMOPLASTIC REACTIONS IN CANINE MAMMARY TUMOURS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR,KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2022-11-10) DEVI S.S; Dr. Ajith Jacob George
    The present study entitled ‘Histomorphological, immunohistochemical and molecular studies on desmoplastic reactions in canine mammary tumours’ was conducted to analyse the role of cancer associated stroma in canine mammary tumours. The histopathological features and grades of tumours were examined in relation to stromal types. As part of the study, the stroma was stratified histomorphologically, expressions of relevant genes and localisation of various proteins involved in stromal reprogramming were examined.A total of 50 canine mammary tumour cases presented to the University Veterinary Hospitals at Mannuthy and Kokkalai during the period from March 2019 to March 2021 were considered for the present study. Occurrence of CMTs was found to be more in female dogs between eight to 12 years. Inguinal glands were found to be the most affected glands. Out of the 50 cases, 39 tumours were malignant of which 30 tumours had either rich or moderate quantity of stroma. These 30 tumours were subjected to histological subtyping and malignancy grading. Ductal carcinomas were identified to be the most common histological type and among the observed cases, Grade II tumours formed the majority. Stroma associated with all these tumours were histomorphologically classified into fibrotic, inflammatory and mixed types. Fibrotic stroma was again subdivided into sclerotic, desmoplastic and stroma of intermediate maturity. On analysing the stromal type in relation to various histological types of CMTs, it was observed that inflammatory or desmoplastic stroma were a feature of highly aggressive tumours like micropapillary carcinoma, comedocarcinoma and carcinosarcoma, while majority of the ductal carcinomas and carcinoma arising in benign mixed tumours had sclerotic stroma. Similarly sclerotic stroma was a feature of Grade I carcinomas while higher grade tumours had either desmoplastic or inflammatory stroma. The cytological features of carcinomas in the study were also analysed in relation to stromal types. Cytological grading of tumours based on the evaluation of stained fine needle aspirated from tumours gave 87.5 per cent concordance rate with histological grading system. Sensitivity and specificity of cytological grading with respect to histological grade was assessed and 100 per cent sensitivity was identified for Grade 1 carcinomas, while the greatest specificity was observed for Grade 3 carcinomas. Grade 1 carcinomas were mainly having sclerotic stroma while Grade 3 carcinomas had either desmoplastic or inflammatory stroma. The desmoplastic stromal reactions in CMTs progressed through the sequential stages of TACS-1, 2 and 3 similar to that described in human breast cancers. Scanning electron microscopy and special staining techniques using Masson’s trichrome, Picrosirius red and Herovici were also employed to demonstrate the desmoplastic reactions occurring in the stroma associated with CMTs. The expression of three main genes involved in desmoplasia and stromal reprogramming namely α-SMA, TGF-β1 and MMP-9 were analysed in normal mammary gland, low grade non metastatic carcinomas and high grade metastatic carcinomas. It was observed that all the three genes were significantly upregulated in high grade metastatic tumours. Along with α-SMA, TGF-β1 and MMP-9, two more proteins of significance viz FAP and SDF-1 were subjected to localisation by IHC. Statistical analysis using Fisher’s exact test revealed significant association between IHC scores of these proteins and grades of tumour. Increased immunostaining corresponded to increase in tumour grades. An understanding of cancer associated stroma (CAS) and its cross talk with tumour cells is very much crucial while predicting prognosis and designing therapeutic protocols. With respect to Veterinary oncology, characterization of CAS, identification of diagnostic and prognostic stromal markers and actionable therapeutic stromal targets remain unexplored even today and thus, the present study was a basic and preliminary attempt to characterise the desmoplastic stromal reactions and identify stromal molecules that could aid in diagnosis, prognosis and treatment of CMTs.
  • Thumbnail Image
    ThesisItemOpen Access
    PORCINE DERIVED SCAFFOLD ASSISTED FULL THICKNESS SKIN WOUND HEALING IN RABBIT MODEL
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2017-06-15) SUVANEETH P; SUVANEETH P; N. Divakaran Nair; N. Divakaran Nair
    The remodeling and regenerative responses of porcine cholecyst on full thickness skin wounds were evaluated in this study using rabbit as an animal model. Comparison of porcine cholecyst, porcine cholecyst seeded with autologous bone marrow cells and open wound control were made for evaluation. Porcine cholecyst was decellularized using a non-enzymatic, non-detergent based protocol and was checked for cellularity prior to in vivo evaluation. The in vivo evaluations were done on full thickness skin wound healing model in New Zealand White rabbits. The inflammatory, remodeling, and regenerative responses were evaluated 7, 14, 21 and 28 days post implantation. The H&E stained sections were evaluated for inflammatory and remodeling responses. Collagenization was evaluated and quantified using Masson’s trichrome and Picrosirius red staining. Differential collagenization was quantified using Herovici staining. Elastin deposition was ascertained using Verhoeff-Van Gieson’s staining. Proliferative response of the fibroblasts was evaluated by argyrophilic nucleolar organizer region (AgNOR) histochemistry and proliferating cell nuclear antigen (PCNA) immunostaining. Dermal cellular proliferation was quantified using PCNA immunohistochemistry. Re-epithelialization and epidermal formation was quantified using cytokeratin based immunohistochemistry. Vimentin immunohistochemistry was used to assess the mesenchymal cell response. ASMA immunohistochemistry was carried out to assess myofibroblast activity and CD 31 for neoangiogenesis. The results of the current study indicated that porcine derived cholecyst scaffolds are very well suited to be used as a bioscaffold material for full thickness skin wound healing, owing to their biochemical, biodegradable, biocompatible and tissue remodeling responses. The use of porcine cholecyst in full thickness skin wounds showed improved epithelialization and faster remodeling devoid of infections or graft rejections in all the animals under study. Scab formation, ulcerations, infections and other complications were also not observed in any of the scaffold assisted wounds. The scaffold enhanced cellular proliferation and keratinocyte activity. Controlled collagenization and faster replacement of immature collagen to mature collagen were also observed in scaffold assisted treatments. Improved neoangiogenesis were seen on scaffold assisted wounds from day seven itself which aided in faster healing of granulation tissue. Complete healing occurred around 14 days in graft assisted treatments, which was significantly early for the size of the wounds. Porcine cholecyst assisted healed wounds showed minimal wound contraction and reduced the chances of scar formation. The presence of autologous marrow cells enhanced proliferating cells, possibly due to the presence of bone marrow derived mesenchymal stem cells, as observed by a higher mesenchymal cell activity in vivo in marrow cells supplied scaffold. Use of autologous marrow cells has improved the time of healing in porcine cholecyst assisted skin wound healing, but not significantly from the application of a non-cell seeded matrix.