Single Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting (SNACS): A tool for demultiplexing single-cell DNA sequencing data.

Motivation: Recently, single-cell DNA sequencing (scDNA-seq) and multi-modal profiling with the addition of cell-surface antibodies (scDAb-seq) have provided key insights into cancer heterogeneity. Scaling these technologies across large patient cohorts, however, is cost and time prohibitive. Multiplexing, in which cells from unique patients are pooled into a single experiment, offers a possible solution. While multiplexing methods exist for scRNAseq, accurate demultiplexing in scDNAseq remains an unmet need. Results: Here, we introduce SNACS: Single-Nucleotide Polymorphism (SNP) and Antibody-based Cell Sorting. SNACS relies on a combination of patient-level cell-surface identifiers and natural variation in genetic polymorphisms to demultiplex scDNAseq data. We demonstrated the performance of SNACS on a dataset consisting of multi-sample experiments from patients with leukemia where we knew truth from single-sample experiments from the same patients. Using SNACS, accuracy ranged from 0.948 - 0.991 vs 0.552 - 0.934 using demultiplexing methods from the single-cell literature.

Takotsubo Cardiomyopathy Associated with Chronic Psychiatric Stress in Major Depressive Disorder in an Elderly Patient

Takotsubo cardiomyopathy (TC) is a transient form of acute heart failure that most often occurs in postmenopausal women, typically triggered by a preceding emotional or physical stressor. A 74-year-old woman who suffered from chronic psychiatric stress visited National Medical Center for dyspnea. Acute emotional or physical stress could not be identified despite careful history taking. An electrocardiogram showed diffuse T-wave inversions with prolonged QT interval, and the echocardiogram showed akinesia of mid and apical segments of the left ventricle with hyperkinesia at the base. There was no significant stenosis on coronary angiography. Differing from the typical case of TC, which follows acute stress triggers, our case indicates that underlying chronic psychiatric illness exacerbation can lead to TC. We suggest that cardiologists and psychiatrists be aware of this predisposition to TC, especially in the circumstances of acute heart failure.

Acute Pancreatitis Induced by Quetiapine in an Elderly Patient

Quetiapine is an atypical antipsychotic that is frequently used to manage delirium in geriatric patients. Acute pancreatitis associated with quetiapine has rarely been reported. A 70-year-old male presented with severe abdominal pain a few hours after taking a dose of quetiapine prescribed for delirium. Despite the lack of risk factors of pancreatitis in his medical history, the patient had a slight increase of serum lipase and amylase levels. His general condition improved on discontinuation of quetiapine. A month later, quetiapine was readministered for the recurrence of delirium. Subsequently, the patient developed the same symptom with a significant increase in serum pancreatic enzyme levels, confirming that quetiapine induced the pancreatitis. We reported the first case of quetiapine-induced pancreatitis in Korea, together with a review of the literature.

A Case of Klippel-Trenaunay Syndrome with Acute Submassive Pulmonary Thromboembolism Treated with Thrombolytic Therapy

Klippel-Trenaunay syndrome is a rare congenital mesodermal abnormality characterized by varicose veins, cutaneous hemangiomas, soft tissue and bony hypertrophy of limb. Potential complications such as deep venous thrombosis and pulmonary thromboembolism have not been reported in Korea to date. We demonstrate the case of a 48-year-old woman with Klippel-Trenaunay syndrome with extensive varicose veins on right lower limb, hypertrophy of left big toe and basilar artery tip aneurysm, complicated with acute submassive pulmonary thromboembolism treated successfully with intravenous thrombolytic therapy.

Severe Resistant Hypertension Induced by Carbamazepine in an Elderly Patient

We report a case of a 73-year-old patient with a 17 year-history of well-controlled primary hypertension with a single antihypertensive drug, which became uncontrolled since 9 months ago when he started on oral carbamazepine (CBZ) therapy for syringomyelia. On admission, the patient had a blood pressure of 200-215/95-104mmHg despite an antihypertensive combination therapy with five different drugs. Further investigations ruled out secondary hypertension such as primary aldosteronism, pheochromocytoma and renal artery stenosis. After the discontinuation of CBZ, the blood pressure profile became significantly improved. The rechallenge with CBZ aggravated his blood pressure profile. Therefore, we considered that resistant hypertension was induced by the oral CBZ therapy.