Thin Film Based Biosensors for Point of Care Diagnosis of Cortisol

This dissertation explores the different ways to create thin film-based biosensors that are capable of rapid and label-free detection of cortisol, a non-specific biomarker closely linked to stress, within the physiological range of 10pM to 10 uM. Increased cortisol levels have been linked to stress-related diseases, such as chronic fatigue syndrome, irritable bowel syndrome, and post-traumatic stress disorder. It also plays a role in the suppression of the immune system as well. Therefore, accurate measurement of cortisol in saliva, serum, plasma, urine, sweat, and hair, is clinically significance to predict physical and mental diseases. In this dissertation, thin film-based electrochemical immunosensors were fabricated using a self-assembled monolayer (SAM) functionalized by cortisol specific antibodies to detect cortisol at 10 pM level sensitivities in the presence of a redox probe. The fabricated electrochemical cortisol immunosensors were able to detect cortisol in human saliva samples and the outcomes were validated using the standard Enzyme Linked Immuno Sorbent Assay (ELISA) technique. With the aim of improving signal amplification and label-free cortisol detection, copper nanoparticles were incorporated on screen-printed carbon electrodes (SPCE) for the fabrication of electrochemical cortisol immunosensor. This SPCE-based sensor showed a sensitivity of 4.21µA/M and the limit of detection 6.6nM. Both the SAM and SPCE-based immunosensors were not thermally stable due to the instability of antibodies at room temperature. To address this issue, an antibody-free immunosensor was fabricated. Molecular Imprinted Polymer (MIP) was used to template the target cortisol molecule. The MIP-based sensing platform was prepared using polypyrrole, a thermally stable conducting polymer. The conductivity of the polymer ensured good electrical performance. The polypyrrole-based MIP was synthesized by means of electrochemical polymerization and was used to detect cortisol within the physiological range at room temperature. MIP-based sensors exhibited the detection limit of 1 pM, and were cost-effective, easy to fabricate, temperature stable, and reusable. The sensing performance of the resulting sensors was comparable to those of commercially available technologies, such as ELISA. Aiming to perform cortisol sensing at point-of-care (POC), an Extended Gate Field Effect Transistor (EGFET) was integrated with a developed MIP cortisol sensor. The as developed MIP-EGFET sensor was used to detect the cortisol concentration in the range of 1 pM to 100 nM. A few of the major advantages of the developed sensor are its ability to provide a direct readout and simpler electronic systems, which are necessary for miniaturized Point of Care devices

Recurrent Dermatofibrosarcoma Protuberans of the Parotid: A case report and review of literature

In 1924, Darier and Ferrand described Dermatofibrosarcoma Protuberans as a progressive and recurring dermatofibroma. It is a locally aggressive sarcoma originating from dermal and subdermal tissue of the skin. It usually begins as a small plaque that grows over a period and later manifests as multiple small subcutaneous nodules. It is more commonly found in females as compared to males and typically occurs in between 2nd and 5th decades of life. Most frequently involved regions of the body are torso and proximal ends of extremities and very rarely head and neck region is the site of involvement. The mainstay of treatment of this entity is surgery. The rate of recurrence of this disease is very high in about 50% of the cases and it may also express rare distant metastasis. It is a radiosensitive tumour and radiation may play a role in reducing risk of recurrence. We present a case of a 35 years old male with recurrent Dermatofibrosarcoma Protuberans of right parotid gland

Ewing sarcoma of larynx: A rare case in a 5-year-old boy

Ewing Sarcoma of the head and neck region is an extremely rare entity. Treatment usually involves surgery, chemotherapy and radiotherapy in varying sequences. We present the third case to date of Ewing sarcoma of the larynx in a paediatric population. A 5-year-old boy presented to emergency room with acute respiratory distress. Computerized tomography scan showed a mass in the supraglottis; he was intubated using videolaryngoscope and tracheostomy was avoided, mass was removed by cold dissection. Final histopathologic examination revealed Ewing sarcoma. Further workup showed no systemic metastasis. Patient was advised adjuvant therapy which the family refused. Currently he is doing fine on 2 years of follow-up

Level I nodal positivity as a factor for involvement of the submandibular gland in oral cavity carcinoma: A case series report

Introduction: The routine practice of neck dissection in the surgical management of oral carcinoma has evolved into a more functionally conservative approach. Over time, the rationale for removal of the submandibular gland has been questioned. Routine extirpation of the submandibular gland can aggravate the xerostomia experienced by many patients, significantly affecting their quality of life. Objective: The objective of the present study was to determine the incidence of submandibular gland metastases in oral cavity carcinoma and to identify possible factors that may affect their involvement. Methods: A total of 149 cases of oral carcinoma presenting at a private tertiary care hospital in Karachi, Pakistan, over the course of 1 year were reviewed retrospectively. Results: Histopathological data showed that the submandibular gland was involved in 7 (4.7%) cases. Involvement of level I lymph nodes was found in all of the cases. Direct extension of primary tumor was noted in two cases when the primary tumor was in the floor of the mouth. Conclusion: The results suggest that preservation of the submandibular gland during neck dissection for oral carcinoma can be practiced safely when there is no evidence of direct extension of the primary tumor toward the submandibular gland or when there is no clinical or radiological evidence of neck disease in level I. Presence of pathological lymph nodes in level I requires caution when contemplating preservation of the submandibular gland

Prevalence of allergic fungal sinusitis among patients with nasal polyposis

Objective: To determine the frequency of allergic fungal sinusitis among patients with nasal polyps, and to compare Lund-Mackay scores of patients with and without allergic fungal sinusitis.Methods: The cross-sectional longitudinal study was conducted at a tertiary healthcare centre in Karachi, Pakistan, from December 2016 to November 2018, and comprised patients with sinonasal polyposis undergoing surgery. The patients were categorised as having allergic fungal sinusitis when histopathology showed allergic mucin with fungal hyphae and culture was positive for fungal growth. Lund-Mackay scoring of each patient was noted and mean scores of allergic fungal sinusitis and non-allergic fungal sinusitis patients were compared. Data was analysed using SPSS 25.Results: Of the 114 patients, 61(53.5%) were males. The overall mean age was 37.3±15.3 years. Of the total, 27(23.7%) patients had allergic fungal sinusitis. There was a significant relationship between asthma and allergic fungal sinusitis (p=0.03). The mean Lund-Mackay score was significantly higher for allergic fungal sinusitis patients (p\u3c0.01). Recurrence was seen in 11(9.6%) cases.Conclusions: About one-fourth of patients with nasal polyps had allergic fungal sinusitis, and such patients showed significantly high mean Lund-Mackay score

Training in temporal bone surgery: A review of current practices

The temporal bone consists of complex anatomy, and the presence of various vital structures in close proximity makes the surgery of temporal bone highly challenging. Such a surgery requires years of training under the direct observation of trainers. Over the course of history, different training models have been adopted by experts to help train the young surgeons in this complex procedure. Cadaveric dissections of the temporal bone remains the gold standard in training of residents as the cadavers present the actual anatomical details which the surgeons encounter while operating on patients. However, due to scarcity of available cadavers, their one-time-only usage and high cost of involved in such trainings, experts have developed newer techniques of training, including three-dimensional reconstruction models and virtual reality simulators. Most of the literature on simulation in training of residents focuses on anatomical understanding and development of the surgical technique. There has been significant improvement in these techniques over time. With the addition of haptic feedback in the newer virtual simulation models, simulation has edged closer to basic modules of temporal bone dissection. the current review article was planned to have an overview of the different techniques in detail that are currently being in used

Management of laryngotracheal trauma: A review of current trends and future directions

Laryngotracheal trauma is rare but can pose serious threats to one\u27s life. Presenting symptoms vary according to the severity of injury. Immediate Airway control is first step in the management, intubation should be considered by a senior member of the trauma team if the injury is minor while tracheostomy should be reserved for more severe injuries. Evaluation by a fibre-optic laryngoscopy and CT scan should be done whenever possible. Reconstruction is done according to the site involved using suture, titanium miniplates and stents. Tissue engineering has added a new horizon in this management but up till now complete laryngotracheal regeneration is very far-fetched, but tissue regeneration at individual sites have shown some positive results. More work needs to be done in this less explored field including laryngeal transplantation