Complex Diagnostic Dilemma of Viral Hepatitis vs. Drug-Induced Hepatitis: A Case Report.

This case report explores the intricate diagnostic challenges encountered in a 30-year-old male patient with abdominal pain, jaundice, and a history of acetaminophen use. Initially presenting as a potential case of drug-induced hepatitis due to acetaminophen overdose, the diagnosis took an unexpected turn when the patient tested positive for hepatitis B surface antigen. The case highlights the complexity of diagnosing acute hepatitis, considering multiple potential etiologies, including viral and drug-induced factors. Differential diagnoses for this case involve considering drug-induced hepatitis, autoimmune hepatitis, various viral hepatitis types, and the potential contribution of cocaine-induced hepatitis as individual possibilities or in combination. This case emphasizes the need for a comprehensive evaluation, the consideration of multiple potential causes, and the importance of ongoing monitoring and follow-up to ensure optimal patient care in cases of acute hepatitis.

Diagnosis of Adrenocortical Carcinoma with Hypercortisolism in a Patient Presenting with Hypokalemic Metabolic Alkalosis.

Adrenocortical carcinoma (ACC) is a rare malignancy with an estimated annual incidence of 0.7-2 cases per million. Most patients present with steroid hormone excess or abdominal mass effects, but 15% of patients with ACC are diagnosed incidentally. A careful history, physical exam, and pertinent lab investigations are necessary to reach the diagnosis. Surgical resection is the cornerstone of treatment in localized ACC; however, systemic chemotherapy with mitotane is preferred in patients with widespread disease or those who are not ideal candidates for surgery.

UNC-18 and Tomosyn Antagonistically Control Synaptic Vesicle Priming Downstream of UNC-13 in Caenorhabditis elegans.

Munc18-1/UNC-18 is believed to prime SNARE-mediated membrane fusion, yet the underlying mechanisms remain enigmatic. Here, we examine how potential gain-of-function mutations of Munc18-1/UNC-18 affect locomotory behavior and synaptic transmission, and how Munc18-1-mediated priming is related to Munc13-1/UNC-13 and Tomosyn/TOM-1, positive and negative SNARE regulators, respectively. We show that a Munc18-1(P335A)/UNC-18(P334A) mutation leads to significantly increased locomotory activity and acetylcholine release in Caenorhabditis elegans, as well as enhanced synaptic neurotransmission in cultured mammalian neurons. Importantly, similar to tom-1 null mutants, unc-18(P334A) mutants partially bypass the requirement of UNC-13. Moreover, unc-18(P334A) and tom-1 null mutations confer a strong synergy in suppressing the phenotypes of unc-13 mutants. Through biochemical experiments, we demonstrate that Munc18-1(P335A) exhibits enhanced activity in SNARE complex formation as well as in binding to the preformed SNARE complex, and partially bypasses the Munc13-1 requirement in liposome fusion assays. Our results indicate that Munc18-1/UNC-18 primes vesicle fusion downstream of Munc13-1/UNC-13 by templating SNARE complex assembly and acts antagonistically with Tomosyn/TOM-1.SIGNIFICANCE STATEMENT At presynaptic sites, SNARE-mediated membrane fusion is tightly regulated by several key proteins including Munc18/UNC-18, Munc13/UNC-13, and Tomosyn/TOM-1. However, how these proteins interact with each other to achieve the precise regulation of neurotransmitter release remains largely unclear. Using Caenorhabditis elegans as an in vivo model, we found that a gain-of-function mutant of UNC-18 increases locomotory activity and synaptic acetylcholine release, that it partially bypasses the requirement of UNC-13 for release, and that this bypass is synergistically augmented by the lack of TOM-1. We also elucidated the biochemical basis for the gain-of-function caused by this mutation. Thus, our study provides novel mechanistic insights into how Munc18/UNC-18 primes synaptic vesicle release and how this protein interacts functionally with Munc13/UNC-13 and Tomosyn/TOM-1.