Molecular engineering of antibodies for site-specific conjugation to lipid polydopamine hybrid nanoparticles

Conjugation of antibodies to nanoparticles allows specific cancer targeting, but conventional conjugation methods generate heterogeneous conjugations that cannot guarantee the optimal orientation and functionality of the conjugated antibody. Here, a molecular engineering technique was used for site-specific conjugation of antibodies to nanoparticles. We designed an anti-claudin 3 (CLDN3) antibody containing a single cysteine residue, h4G3cys, then linked it to the maleimide group of lipid polydopamine hybrid nanoparticles (LPNs). Because of their negatively charged lipid coating, LPNs showed high colloidal stability and provided a functional surface for site-specific conjugation of h4G3cys. The activity of h4G3cys was tested by measuring the binding of h4G3cys-conjugated LPNs (C-LPNs) to CLDN3-positive tumor cells and assessing its subsequent photothermal effects. C-LPNsspecifically recognized CLDN3-overexpressing T47D breast cancer cells but not CLDN3-negative Hs578T breast cancer cells. High binding of C-LPNs to CLDN3-overexpressing T47D cells resulted in significantly higher temperature generation upon NIR irradiation and potent anticancer photothermal efficacy. Consistent with this, intravenous injection of C-LPNsin a T47D xenograft mouse model followed by NIR irradiation caused remarkable tumor ablation compared with other treatments through high temperature increases. Our results establish an accurate antibody-linking method and demonstrate the possibility of developing therapeutics using antibody-guided nanoparticles.     

Pictorial Review of Mediastinal Masses with an Emphasis on Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) has become a crucial tool for evaluating mediastinal masses considering that several lesions that appear indeterminate on computed tomography and radiography can be differentiated on MRI. Using a three-compartment model to localize the mass and employing a basic knowledge of MRI, radiologists can easily diagnose mediastinal masses. Here, we review the use of MRI in evaluating mediastinal masses and present the images of various mediastinal masses categorized using the International Thymic Malignancy Interest Group''s three-compartment classification system. These masses include thymic hyperplasia, thymic cyst, pericardial cyst, thymoma, mediastinal hemangioma, lymphoma, mature teratoma, bronchogenic cyst, esophageal duplication cyst, mediastinal thyroid carcinoma originating from ectopic thyroid tissue, mediastinal liposarcoma, mediastinal pancreatic pseudocyst, neurogenic tumor, meningocele, and plasmacytoma.     

Reliability of Skeletal Muscle Area Measurement on CT with Different Parameters: A Phantom Study

ObjectiveTo evaluate the reliability of CT measurements of muscle quantity and quality using variable CT parameters.Materials and MethodsA phantom, simulating the L2–4 vertebral levels, was used for this study. CT images were repeatedly acquired with modulation of tube voltage, tube current, slice thickness, and the image reconstruction algorithm. Reference standard muscle compartments were obtained from the reference maps of the phantom. Cross-sectional area based on the Hounsfield unit (HU) thresholds of muscle and its components, and the mean density of the reference standard muscle compartment, were used to measure the muscle quantity and quality using different CT protocols. Signal-to-noise ratios (SNRs) were calculated in the images acquired with different settings.ResultsThe skeletal muscle area (threshold, −29 to 150 HU) was constant, regardless of the protocol, occupying at least 91.7% of the reference standard muscle compartment. Conversely, normal attenuation muscle area (30–150 HU) was not constant in the different protocols, varying between 59.7% and 81.7% of the reference standard muscle compartment. The mean density was lower than the target density stated by the manufacturer (45 HU) in all cases (range, 39.0–44.9 HU). The SNR decreased with low tube voltage, low tube current, and in sections with thin slices, whereas it increased when the iterative reconstruction algorithm was used.ConclusionMeasurement of muscle quantity using HU threshold was reliable, regardless of the CT protocol used. Conversely, the measurement of muscle quality using the mean density and narrow HU thresholds were inconsistent and inaccurate across different CT protocols. Therefore, further studies are warranted in future to determine the optimal CT protocols for reliable measurements of muscle quality.     

The Importance of Early Recognition,Timely Management,and the Role of Healthcare Providers in Multisystem Inflammatory Syndrome in Children

In April 2020, a pediatric report of an unusual inflammatory illness associated with coronavirus disease 2019 (COVID-19) led to similar cases in Europe and North America, which was referred to as multisystem inflammatory syndrome in children (MIS-C). Herein, we describe the case of a 12-year-old boy who had a history of polymerase chain reaction-confirmed COVID-19 and developed MIS-C approximately three weeks after an initial diagnosis of COVID-19. High fever with abdominal pain mimicking appendicitis was the initial manifestation of MIS-C, which could have been easily missed if the patient''s history of COVID-19 was ignored. Intravenous immunoglobulin was administered twice, 24 hours apart, five days after the onset of MIS-C, and the patient fully recovered without any obvious sequelae. Early recognition by disease awareness and prompt management are the keys to saving the lives of children affected by MIS-C.     

Impact of an Education Program for Caregivers of Patients with Alzheimer's Disease on Treatment Discontinuation and Compliance in Korea

Background and PurposeReportedly 30–50% of patients being treated for chronic illnesses do not adhere to their medication regimen. We assessed the impact of a nurse-led education program for caregivers of Korean de novo Alzheimer''s disease patients who had newly been prescribed donepezil.MethodsThis multicenter study analyzed 93 participants in a caregiver education group and 92 participants in a caregiver no-education group. At every visit up to the end of the study (1 year), caregivers in the education group were given educational brochures regarding Alzheimer''s disease and the efficacy and adverse events of donepezil treatment. The primary endpoint was the discontinuation rate of donepezil treatment during the 1-year observation period. The secondary endpoints included the effect of education on compliance with donepezil treatment assessed at each visit using a clinician rating scale (CRS) and visual analog scale (VAS), and changes from baseline in cognitive assessment tests.ResultsThe donepezil discontinuation rates at 1 year were 5.38% (5/93) and 6.52% (6/92) in the caregiver education and no-education groups, respectively (p=0.742). No significant between-group differences in donepezil compliance rates on the CRS and VAS were observed, but significant changes were observed in some cognitive tests from baseline to the end of the study.ConclusionsCaregiver education had no significant effect on treatment discontinuation, but this may have been due to the low severity of cognitive impairment among the included population at baseline. In addition, the low discontinuation rates meant that no significant difference in treatment compliance was observed.     

ANCA-Negative Wegener's Granulomatosis with Multiple Lower Cranial Nerve Palsies

Wegener''s granulomatosis (WG) is a systemic vasculitis affecting small and medium-sized vessels with granulomatous formation. Though it is known for respiratory tract and kidney involvement, neurologic manifestation has been also reported. Herein we report a patient who suffered pansinusitis with multiple lower cranial nerve palsies but reached remission by immunosuppressant after the diagnosis of WG. A 54-yr-old female visited with headache, hearing difficulty, and progressive bulbar symptoms. She experienced endoscopic sinus surgeries due to refractory sinusitis. Neurologic examination revealed multiple lower cranial nerve palsies. Vasculitic markers showed no abnormality. Nasal biopsy revealed granulomatous inflammation and vasculitis involving small vessels. Given cyclophosphamide and prednisolone, her symptoms were prominently improved. WG should be considered in the patient with multiple cranial nerve palsies, especially those with paranasal sinus disease. Because WG can be lethal if delayed in treatment, prompt immunosuppressant is warranted after the diagnostic tissue biopsy.     

Long-term Outcomes of Endoscopic Variceal Ligation to Prevent Rebleeding in Children with Esophageal Varices

After an episode of acute bleeding from esophageal varices, patients are at a high risk for recurrent bleeding and death. However, there are few reports regarding the long-term results of secondary prophylaxis using endoscopic variceal ligation (EVL) against variceal rebleeding in pediatrics. Thirty-seven, who were followed for over 3 yr post-eradication, were included in the study. The mean duration of follow up after esophageal variceal eradication was 6.4±1.9 yr. The mean time required to achieve the eradication of varices was 3.25 months. The mean number of sessions and O-bands needed to eradicate varices was 1.9±1.2 and 3.8±1.5, respectively. During the period before the first EVL treatment, 145 episodes of bleedings developed in 37 children. Over the 3 yr of follow-up after variceal eradication, only 4 episodes of rebleeding developed in 4 of 37 patients. The four rebleeding episodes consisted of an esophageal variceal bleed, a gastric variceal bleed, a duodenal ulcer bleed, and a bleed caused by hemorrhagic gastritis. There was no mortality during long-term follow up after variceal eradication. During long-term follow up after esophageal variceal eradication using solely EVL in children with esophageal variceal bleeds, rebleeding episodes and recurrence of esophageal varices were rare. EVL is a safe and highly effective method for the long-term prophylaxis of variceal rebleeding in children with portal hypertension.     

Bilateral variations of musculocutaneous nerves with rare pattern in a Korean female cadaver

Bilateral variations in the formation and branching of brachial plexus are rare. Variations between median and musculocutaneous nerves were observed on both sides during the dissection of an 87-year-old Korean female cadaver, whose cause of death was cholangiocarcinoma. The variations found were bilateral, in which each musculocutaneous nerve did not pierce the coracobrachialis muscle. The musculocutaneous nerve was rudimentary in the right arm and all branches arose from the median nerve separately, which corresponds to previous classification type 0-2. In the case of the left arm, the musculocutaneous nerve originated from the lateral cord, but had connections between median and musculocutaneous nerves below the coracobrachialis muscle, which corresponds to previous classification type 1-B-2. To the best of our knowledge, the bilateral variations between median and musculocutaneous nerves in this case have different features from other previous reports. Awareness of the possible variations between median and musculocutaneous nerves is important to both anatomists and clinicians.