Automatic registration of dental CT and 3D scanned model using deep split jaw and surface curvature.

BACKGROUND AND OBJECTIVES: In the medical field, various image registration applications have been studied. In dentistry, the registration of computed tomography (CT) volume data and 3D optically scanned models is essential for various clinical applications, including orthognathic surgery, implant surgical planning, and augmented reality. Our purpose was to present a fully automatic registration method of dental CT data and 3D scanned models. METHODS: We use a 2D convolutional neural network to regress a curve splitting the maxilla (i.e., upper jaw) and mandible (i.e., lower jaw) and the points specifying the front and back ends of the crown from the CT data. Using this regressed information, we extract the point cloud and vertices corresponding to the tooth crown from the CT and scanned data, respectively. We introduce a novel metric, called curvature variance of neighbor (CVN), to discriminate between highly fluctuating and smoothly varying regions of the tooth crown. The registration based on CVN enables more accurate fine registration while reducing the effects of metal artifacts. Moreover, the proposed method does not require any preprocessing such as extracting the iso-surface for the tooth crown from the CT data, thereby significantly reducing the computation time. RESULTS: We evaluated the proposed method with the comparison to several promising registration techniques. Our experimental results using three datasets demonstrated that the proposed method exhibited higher registration accuracy (i.e., 2.85, 1.92, and 7.73 times smaller distance errors for individual datasets) and smaller computation time (i.e., 4.12 times faster registration) than one of the state-of-the-art methods. Moreover, the proposed method worked considerably well for partially scanned data, whereas other methods suffered from the unbalancing of information between the CT and scanned data. CONCLUSIONS: The proposed method was able to perform fully automatic and highly accurate registration of dental CT data and 3D scanned models, even with severe metal artifacts. In addition, it could achieve fast registration because it did not require any preprocessing for iso-surface reconstruction from the CT data.

COVID-19 and changes in content usage behavior: The case of South Korea.

This study examines changes in content usage time due to the COVID-19 pandemic in South Korea using Korean Media Panel data for the period 2011-2020 and explores the reasons for these changes. This study focuses on four principal contents: television programs, movies/videos/user-created content, traditional telecommunication services, and chatting/messenger/social network services. The empirical results indicate an increase in usage time for the four principal contents, as well as total content usage time because of the pandemic. The results also show that average Korean people stayed longer at home after the onset of the pandemic, leading to an increase in the time spent on all the principal contents, except for traditional telecommunication services, as well as an increase in total content usage time. Furthermore, this study suggests that whereas the effect of the pandemic on television program viewing time was mainly attributable to changes in time spent at home because of the pandemic, the effect on other contents was mainly caused by non-location-related factors. This study predicts changes in content usage time after the end of the pandemic and provides strategic suggestions.

Analysis of Time-Dependent Pharmacokinetics Using In Vitro-In Vivo Extrapolation and Physiologically Based Pharmacokinetic Modeling.

SCR430, a sorafenib derivative, is an investigational drug exhibiting anti-tumor action. This study aimed to have a mechanistic understanding of SCR430's time-dependent pharmacokinetics (TDPK) through an ex vivo study combined with an in vitro-in vivo extrapolation (IVIVE) and physiologically based pharmacokinetic (PBPK) modeling. A non-compartmental pharmacokinetic analysis was performed after intravenous SCR430 administration in female Sprague-Dawley rats for a control group (no treatment), a vehicle group (vehicle only, 14 days, PO), and a repeated-dosing group (SCR430, 30 mg/kg/day, 14 days, PO). In addition, hepatic uptake and metabolism modulation were investigated using isolated hepatocytes from each group of rats. The minimal PBPK model based on IVIVE was constructed to explain SCR430's TDPK. Repeated SCR430 administration decreased the systemic exposure by 4.4-fold, which was explained by increased hepatic clearance (4.7-fold). The ex vivo study using isolated hepatocytes from each group suggested that the increased hepatic uptake (9.4-fold), not the metabolic activity, contributes to the increased hepatic clearance. The minimal PBPK modeling based on an ex vivo study could explain the decreased plasma levels after the repeated doses. The current study demonstrates the TDPK after repeated dosing by hepatic uptake induction, not hepatic metabolism, as well as the effectiveness of an ex vivo approach combined with IVIVE and PBPK modeling to investigate the TDPK.

Acute Hepatitis A-Induced Autoimmune Hepatitis: A Case Report and Literature Review.

INTRODUCTION: The pathogenesis of autoimmune hepatitis (AIH) is little known. Previous case reports suggest that several viral hepatitis, including hepatitis A, can trigger AIH. PATIENT: A 55-year-old female showed general weakness and jaundice. The patient was diagnosed with acute hepatitis A and discharged after 14 days of hospitalization with improving liver function. However, blood tests performed 6 days after discharge revealed an increase in liver enzymes and high serum titers of an anti-nuclear antibody and immunoglobulin G. She was readmitted for liver biopsy. DIAGNOSIS: Liver biopsy showed acute hepatitis A along with AIH. According to the revised international autoimmune hepatitis group scoring system, her score was 14 and she was diagnosed as AIH induced by acute hepatitis A. INTERVENTION: Conservative treatments with crystalloid (Lactated Ringer's Solution), ursodeoxycholic acid, and silymarin were administered. OUTCOMES: The patient has been followed up on an outpatient basis and neither symptom recurrence nor an increase in liver enzymes has been reported thus far. LESSONS: After the treatment of acute hepatitis A, liver function needs to be carefully monitored over time, and the possibility of autoimmune hepatitis should be considered when liver enzymes increases.

A Population Pharmacokinetic Model of Intravenous Dexmedetomidine for Mechanically Ventilated Children after Neurosurgery.

Dexmedetomidine is a selective alpha-2 adrenergic agonist with concurrent sedative and analgesic effects, and it is being increasingly used in pediatric anesthesia and intensive care. This study aimed to investigate the pharmacokinetics of intravenous dexmedetomidine in mechanically ventilated children in the intensive care unit (ICU) after neurosurgery. Pediatric patients aged 2-12 years, who were mechanically ventilated in ICU after neurosurgery, were allocated into a low-dose (n = 15) or high-dose (n = 14) group. The low-dose group received dexmedetomidine at a loading dose of 0.25 µg/kg for 10 min, followed by a maintenance dose of 0.25 µg/kg/h for 50 min, whereas the high-dose group received dexmedetomidine at a loading dose of 0.5 µg/kg for 10 min, followed by a maintenance dose of 0.5 µg/kg/h for 50 min. Serial blood samples were collected for a pharmacokinetic analysis up to 480 min after the end of the infusion. The sedative effect of dexmedetomidine was assessed using the Bispectral Index and University of Michigan Sedation Scale. Adverse reactions, electrocardiography findings, and vital signs were monitored for a safety assessment. A population pharmacokinetic analysis was performed using non-linear mixed effects modeling. Dexmedetomidine induced a moderate-to-deep degree of sedation during infusion in both groups. The pharmacokinetics of dexmedetomidine were best described by a two-compartment disposition model with first-order elimination kinetics. The parameters were standardized for a body weight of 70 kg using an allometric power model. The population estimates (95% confidence interval) per 70 kg body weight were as follows: clearance of 81.0 (72.9-90.9) L/h, central volume of distribution of 64.2 (50.6-81.0) L, intercompartment clearance of 116.4 (90.6-156.0) L/h, and peripheral volume of distribution of 167 (132-217) L. No serious adverse reactions or hemodynamic changes requiring the discontinuation of dexmedetomidine were observed. Dexmedetomidine had increased clearance and volume of distribution in mechanically ventilated children in ICU after neurosurgery, thereby indicating the need to adjust the dosage to obtain a target plasma concentration.

Molecular and biochemical characterization of the GALT gene in Korean patients with galactose-1-phosphate uridyltransferase deficiency.

BACKGROUND: Three different types of galactosemia have been described, and the most common form occurs due to a deficiency in the galactose-1-phosphate uridyltransferase (GALT) enzyme activity. METHODS: To investigate the molecular defects of the GALT gene, PCR-direct sequencing was performed with genomic DNA from 18 Korean patients with reduced GALT activity. RESULTS: Of the 18 patients tested, 13 (72.2%) had previously reported variants: Duarte variant (12 patients), p.R201H (1 patient), and g.A1962G. In addition, we identified six novel sequence variations by PCR-direct sequencing: five sequence variations in coding regions (p.H31R, p.L116I, p.Q169H, p.H186P and p.R333R), and one in an intron (g.2621A>G). Of 100 normal individuals tested, 4 were heterozygous for the Duarte variant, which indicates a Duarte allele frequency of 2%. Biochemical characteristics of the novel genetic alterations were determined: enzyme activity for exonic alterations and splicing for intron. CONCLUSION: The genetic constitution of the GALT gene is responsible for galactosemia in the Korean population.