Publications by authors named "Chulho Oak"

Background: Lung cancer, especially non-small cell lung cancer (NSCLC), poses a significant health challenge globally due to its high mortality. Afatinib, a second-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), has shown superior efficacy over traditional chemotherapy in NSCLC treatment. However, issues like secondary resistance and adverse effects call for alternative therapies.

View Article and Find Full Text PDF

Purpose: This study aimed to evaluate the prevalence, trends, and factors of preserved ratio with impaired spirometry (PRISm) by using a nationally representative sample.

Patients And Methods: The datasets of the Korea National Health and Nutrition Examination Survey 2010-2019 were used: of total 32,949 participants aged ≥40 and no missing data on spirometry, 24,523 with normal, 4,623 with obstructive, and 3,803 with PRISm were identified. PRISm was defined as FEV1/FVC ≥70% and FEV1% of the predicted value (%pred) <80.

View Article and Find Full Text PDF

(1) Background: An early mesothelial reaction of the pleura, leading to fibrosis, has been reported in animals after chemical or heavy metal exposure. However, the visual monitoring of early time-sequential mesothelial reaction-associated cryoinjury has not been fully investigated. Therefore, this study aimed to evaluate and visualize the early mesothelial reactions seen following cryoinjury using rabbit pleura.

View Article and Find Full Text PDF

Background: Multiple attempts have been made to use biological samples other than sputum to diagnose tuberculosis (TB). Sputum acid-fast bacillus (AFB) microscopy is the fastest, most straightforward, and most inexpensive method for diagnosing pulmonary TB. However, urine can be used in place of sputum owing to its various advantages, such as a noninvasive method of collection, convenient handling and storage, and minimal risk of infection in health-care workers involved in sample collection.

View Article and Find Full Text PDF

Background: We aimed to validate a pilot study of photodiagnosis using near infrared (NIR) transillumination and assess the clinical efficacy of hypericin-mediated photodynamic therapy (HYP-PDT) in a rabbit laryngeal cancer model in order to develop a novel therapeutic modality with complete remission and preservation of the functional organ.

Methods: (1) In vitro study: VX tumor cells were subcultured and subjected to HYP-PDT. (2) In vivo study: A laryngeal cancer model was developed in which 12 rabbits were inoculated with a VX tumor suspension in the submucosal area of the left vocal fold using a transoral approach.

View Article and Find Full Text PDF

Background: The vocal cord tissue consists of three anatomical layers from the surface to deep inside: the epithelium that contains almost no collagen, the lamina propria that is composed of abundant collagen, and the vocalis muscle layer. It is clinically important to visualize the tissue microstructure using a non-invasive method, especially in the case of vocal cord nodules or cancer, since histological changes in each layer of the vocal cord cause changes in the voice. Polarization-sensitive optical coherence tomography (PS-OCT) enables phase retardation measurement to evaluate birefringence of tissue with varied organization of collagen fibers in different tissue layers.

View Article and Find Full Text PDF
Article Synopsis
  • Polarization sensitive-optical coherence tomography (PS-OCT) is a technique that uses polarized light to examine the optical properties of tissues, particularly useful for visualizing intercostal muscles under the pleura, where traditional imaging methods fall short.
  • This study utilized PS-OCT to detect subpleural cancer in rabbits, injecting cancer cells into the intercostal area and analyzing changes in pleura thickness and muscle damage over 7 to 14 days compared to pathology results.
  • The findings suggest that PS-OCT can effectively visualize and assess subpleural cancer, providing valuable structural and functional information that may aid in identifying tumor margins and could lead to advancements in imaging for other diseases.
View Article and Find Full Text PDF

Background: Afatinib is an epidermal growth factor receptor - tyrosine kinase inhibitor (EGFR-TKI) with proven efficacy for treating patients with advanced or metastatic non-small cell lung cancer (NSCLC). Unfortunately, responses are limited by acquired resistance. Because traditional Korean medicine may have synergistic effects when combined with chemotherapy or radiotherapy, the aim of our study is to elucidate the efficacy and safety of afatinib plus HangAmDan-B1 (HAD-B1) combination therapy in the treatment of patients with NSCLC, as well as EGFR mutations, who need afatinib therapy.

View Article and Find Full Text PDF

The Asbestos Injury Relief Act in Korea requires that asbestos exposure be assessed through clinical examination and chest computed tomography (CT). However, a more specific measurement of asbestos characteristics in the lung tissue may be appropriate. We aimed to investigate the asbestos burden and characterize asbestos fibers in patients with lung cancer and ultimately assess the relationship between occupational and environmental asbestos exposure and lung cancer in Korea.

View Article and Find Full Text PDF

Folate, folic acid, has a role in mitigating inflammatory reactions in the human body. This study aimed to evaluate the association of serum folate levels with lung function in chronic obstructive pulmonary disease (COPD) patients. Of the 8149 participants of the 2016 Korean National Health and Nutrition Examination Survey (KNHANES), 311 subjects (192 males and 119 females) having COPD defined by the lower fifth percentile of the reference population were selected.

View Article and Find Full Text PDF
Article Synopsis
  • * A study found that phlorotannin, a compound derived from the brown alga Ecklonia cava, can inhibit fibroblast growth and reduce fibrosis in tracheal tissues in rabbits.
  • * Phlorotannin-coated endotracheal tubes release the compound for up to 7 days and show promising results in reducing fibrogenesis, suggesting they could be a viable solution for preventing tracheal stenosis.
View Article and Find Full Text PDF

Tracheal tumors are rare and difficult to diagnose. Moreover, delays in diagnosis are very common because the symptoms are nonspecific. As a result, tracheal tumors are commonly mistreated as chronic obstructive pulmonary disease or bronchial asthma.

View Article and Find Full Text PDF

Background: Studies to date have shown that near-infrared autofluorescence imaging (NIR) can detect the parathyroid gland during thyroidectomy. However, there are no reports that NIR imaging can identify the parathyroid gland when it's covered with fibrofatty tissue before identification by a surgeon's naked eye. In this study, we investigated the feasibility of parathyroid gland mapping to facilitate early identification of the parathyroid gland during thyroidectomy.

View Article and Find Full Text PDF

Background And Objective: Variable methods of animal model have been introduced to develop tracheal stenosis. However, none of the prior models allow for predictable determination of the grade of stenosis. This study sought to establish an animal model of tracheal stenosis by using a cylindrical diffuser and to evaluate the feasibility of a reproducible model.

View Article and Find Full Text PDF

Context: This biomedical investigation is valuable for identification and localization of parathyroid glands during thyroidectomy, which can provide an intraoperative real-time visual guidance.

Objective: The objective of the study was to investigate the feasibility of real-time autofluorescence imaging of the parathyroid glands without exogenous contrast dye for their localization and demonstration of relation to the background tissues.

Setting: This research was undertaken at Kosin University Gospel Hospital.

View Article and Find Full Text PDF

Background/aims: It is not clear which tests are indicative of the activity and severity of tuberculosis (TB). This study aimed to investigate the predictive value of neuron-specific enolase (NSE) and to determine the origin of NSE in TB patients.

Methods: A single-center retrospective analysis was conducted on newly diagnosed TB patients between January and December 2010.

View Article and Find Full Text PDF

Background And Objectives: We evaluated the feasibility of using optical coherence tomography (OCT), to identify microscopic extrathyroidal extension (mETE) in ex vivo thyroidectomy specimens of patients who underwent thyroidectomy for the treatment of papillary thyroid carcinoma (PTC).

Methods: A total of 170 ex vivo OCT images of the tumor, were acquired just after completion of thyroidectomy in 17 patients. The OCT images of each patient were separately evaluated by two blinded investigators, and the outcomes were compared with the histopathology reports.

View Article and Find Full Text PDF

Objective: Animal model of tracheal stenosis based on pathophysiology of prolonged endotracheal intubation has been rarely reported. We sought to verify the feasibility of inducing an animal model of tracheal stenosis by segmented endotracheal tube insertion in the New Zealand white rabbit model.

Methods: Tracheal stenosis was induced by inserting a segmented endotracheal tube of 1.

View Article and Find Full Text PDF

Background And Objective: Optical coherence tomography (OCT) provides ultrahigh-resolution imaging of tissues within a depth of a few millimeters, whereas ultrasonography provides good imaging further below the surface. We aimed to develop a minimally invasive rabbit model of VX2 laryngeal cancer, suitable for these two imaging modalities through a transoral approach. We also sought to study the utility of combined OCT and endolaryngeal ultrasonography (EUS) for evaluation of early and advanced laryngeal cancer, using this model.

View Article and Find Full Text PDF

Tuberculosis (TB) is an infectious bacterial disease that has historically created a high global health burden. Unfortunately, the emergence of drug-resistant TB (DR-TB), which includes multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), has greatly affected the treatment of TB. Anti-TB chemotherapy drugs are classified into five groups to facilitate application of effective guidelines for the treatment regimen.

View Article and Find Full Text PDF

Background And Objective: Asthmatic patients exhibit airway hyper-responsiveness, which induces bronchoconstriction and results in a ventilation defect. The bronchial challenge test using methacholine is a useful way to measure airway hyper-responsiveness with airway constriction. Anatomical optical coherence tomography has been used to image airway hyper-responsiveness of medium sized bronchus with the aid of an endoscopic probe.

View Article and Find Full Text PDF

Titanium dioxide (TiO2) is increasingly widely used in industrial, commercial and home products. TiO2 aggravates respiratory symptoms by induction of pulmonary inflammation although the mechanisms have not been well investigated. We aimed to investigate lung inflammation in rabbits after intratracheal instillation of P25 TiO2.

View Article and Find Full Text PDF

Recent studies have shown that thymosin β4 (Tβ4) stimulates angiogenesis by inducing vascular endothelial growth factor (VEGF) expression and stabilizing hypoxia inducible factor-1α (HIF-1α) protein. Pulmonary tuberculosis (TB), a type of granulomatous disease, is accompanied by intense angiogenesis and VEGF levels have been reported to be elevated in serum or tissue inflamed by pulmonary tuberculosis. We investigated the expression of Tβ4 in granulomatous lung tissues at various stages of active pulmonary tuberculosis, and we also examined the expression patterns of VEGF and HIF-1α to compare their Tβ4 expression patterns in patients' tissues and in the tissue microarray of TB patients.

View Article and Find Full Text PDF

Acquired airway injury is frequently caused by endotracheal intubations, long-term tracheostomies, trauma, airway burns, and some systemic diseases. An effective and less invasive technique for both the early assessment and the early interventional treatment of acquired airway stenosis is therefore needed. Optical coherence tomography (OCT) has been proposed to have unique potential for early monitoring from the proliferative epithelium to the cartilage in acute airway injury.

View Article and Find Full Text PDF