Nicotine addiction is a concern worldwide. Most mechanistic investigations are on nicotine substance dependence properties based on its pharmacological effects. However, no effective therapeutic treatment has been established. Nicotine addiction is reinforced by environments or habits. We demonstrate the neurobiological basis of the behavioural aspect of nicotine addiction. We utilized the conditioned place preference to establish nicotine-associated behavioural preferences (NABP) in rats. Brain-wide neuroimaging analysis revealed that the medial prefrontal cortex (mPFC) was activated and contributed to NABP. Chemogenetic manipulation of µ-opioid receptor positive (MOR⁺) neurons in the mPFC or the excitatory outflow to the nucleus accumbens shell (NAcShell) modulated the NABP. Electrophysiological recording confirmed that the MOR⁺ neurons directly regulate the mPFC-NAcShell circuit via GABA_A receptors. Thus, the MOR⁺ neurons in the mPFC modulate the formation of behavioural aspects of nicotine addiction via direct excitatory innervation to the NAcShell, which may provide new insight for the development of effective therapeutic strategies.
Animals ; Nucleus Accumbens/drug effects* ; Prefrontal Cortex/drug effects* ; Nicotine/pharmacology* ; Receptors, Opioid, mu/metabolism* ; Male ; Rats ; Rats, Sprague-Dawley ; Tobacco Use Disorder/metabolism* ; Neurons/drug effects* ; Neural Pathways/drug effects*

Endoscopic papillectomy (EP) for ampullary adenomas achieves cure rates ranging from 76% to 90%, and recurrence rates are as high as 33%. If remnant or recurrent lesions after prior EP are endoscopically visible and are not suspected of intraductal extension into the biliary or pancreatic duct, repeated snaring and cutting can be performed until all visible lesions are completely resected. However, endoscopic ablative therapies, particularly argon plasma coagulation, can be attempted for tiny or uncertain remnant and recurrent lesions. In addition, intraductal radiofrequency ablation has recently been attempted for residual intraductal lesions after EP at several institutions. Although still under investigation, it has shown some promise. It might be offered as an alternative to surgery, particularly in patients who are unfit for surgery or those who refuse to undergo surgery.

Severe burn injuries often result in significant long-term physical complications with scarring and contractures, but cancers associated with chronic burn scars are relatively rare. We report a case of a 58-year-old man with skin cancer arising from a healed burn scar. He initially suffered from an extensive fire burn on both lower limbs as a child. The burn scars extended from his upper thighs to his toes bilaterally and caused severe contractures which immobilized the ankles in plantar flexion. Two years ago, he noticed a small ulcerated lesion on the right heel and self-treated it with topical ointments. However, the ulcer increased in size and became malodorous. He presented to a clinic with a large, ulcerated, tumorous lesion, and histology proved it to be squamous cell carcinoma. He subsequently underwent a right below-the-knee amputation, and the previous scars presented on the stump. Thus the patient received a total surface bearing prosthesis with an Icelandic roll-on silicone socket system, which is ideal for patients with extensive scarring at the stump because it may reduce prosthesis-induced stump injuries by evenly distributing the patient's weight in the socket. After he left the hospital, he walked so far with the prosthesis every day that small ulcers often developed at the right popliteal fossa. However, he did not take care to treat these lesions properly, so we had to educate him on how to treat them. Patients such as these will often require education for self-management, family involvement and regular follow-up to monitor scar ulceration and watch out for any malignant transformation.