Synthesis, Antiproliferative Activity and Molecular Docking Analysis of Both Enantiomerically Pure Decursin Derivatives as Anticancer Agents.

Using (S)-decursinol isolated from root of Angelica gigas Nakai (AGN), we semi-synthesized and evaluated a series of both enantiomerically pure decursin derivatives for their antiproliferative activities against A549 human lung cancer cells. All synthesized compounds showed a broad spectrum of inhibitory activities against the growth of A549 cells. Especially, compound (S)-2d with (E)-(furan-3-yl)acryloyl group showed the most potent activity (IC50: 14.03 µM) against A549 cancer cells as compared with the reference compound, decursin (IC50: 43.55 µM) and its enantiomer, (R)-2d (IC50: 151.59 µM). Western blotting assays indicated that (S)-2d more strongly inhibited Janus kinase 1 (JAK1) and signal transducer and activator of transcription activation 3 (STAT3) phosphorylation than decursin in a dose-dependent manner, while having no effect on CXCR7 overexpression and total STAT3 level. In addition, (S)-2d induced cell cycle arrest at G1 phase and subsequent apoptotic cell death in A549 cancer cells. Our combined analysis of molecular docking studies and biological data suggests that the inhibition of JAK1 with (S)-2d resulted in loss of STAT3 phosphorylation and inhibition of cell growth in A549 cancer cells. These overall results strongly suggest that (S)-2d (MRC-D-004) as a novel JAK1 inhibitor may have therapeutic potential in the treatment of A549 human lung cancers by targeting the JAK1/STAT3 signaling pathway.

Density-Dependent Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Hormone-Releasing Cells.

Mesenchymal stem cells (MSCs) can differentiate into endoderm lineages, especially parathyroid-hormone (PTH)-releasing cells. We have previously reported that tonsil-derived MSC (T-MSC) can differentiate into PTH-releasing cells (T-MSC-PTHCs), which restored the parathyroid functions in parathyroidectomy (PTX) rats. In this study, we demonstrate quality optimization by standardizing the differentiation rate for a better clinical application of T-MSC-PTHCs to overcome donor-dependent variation of T-MSCs. Quantitation results of PTH mRNA copy number in the differentiated cells and the PTH concentration in the conditioned medium confirmed that the differentiation efficiency largely varied depending on the cells from each donor. In addition, the differentiation rate of the cells from all the donors greatly improved when differentiation was started at a high cell density (100% confluence). The large-scale expression profiling of T-MSC-PTHCs by RNA sequencing indicated that those genes involved in exiting the differentiation and the cell cycle were the major pathways for the differentiation of T-MSC-PTHCs. Furthermore, the implantation of the T-MSC-PTHCs, which were differentiated at a high cell density embedded in hyaluronic acid, resulted in a higher serum PTH in the PTX model. This standardized efficiency of differentiation into PTHC was achieved by initiating differentiation at a high cell density. Our findings provide a potential solution to overcome the limitations due to donor-dependent variation by establishing a standardized differentiation protocol for the clinical application of T-MSC therapy in treating hypoparathyroidism.

Feasibility of injectable thermoreversible gels for use in intramuscular injection of parathyroid autotransplantation.

Surgical transplantation of parathyroid tissue into the forearm muscle is one of the most commonly used surgical techniques. While simple, the procedure suffers from drawbacks. This study evaluated the feasibility of thermoreversible gel as an injectable carrier for parathyroid autotransplantation. Polyethyleneglycol-polyalanine-co-phenylalanine (PEG-PAF) thermoreversible gel (sol form at 4 °C, gel form at 37 °C) were manufactured. Thirty-eight Sprague-Dawley rats were divided into two groups (19 control, C group; 19 experimental, P group). The parathyroid glands of rats were excised. Parathyroid tissues were transplanted into the muscle pocket in sternocleidomastoid muscle in the C group. In the P group, the tissues were injected into the same muscle mixed with 0.3 ml thermoreversible gel. The serum levels of parathyroid hormone (PTH), ionized calcium, and phosphorous were measured before surgical procedure, on 7, 21, 56, and 70 days after surgery. Histology and immunohistochemistry were performed. Preoperative median PTH level of the C and the P group were 60.80 and 43.85 pg/ml, respectively (p = 0.641). Seventy days after surgery, median PTH level was 32.8 and 25.61 pg/ml, respectively. On day 70, the PTH level was restored by 54 % in the C group and 56 % in the P group compared to the preoperative value (p = 0.620). There were no significant intergroup differences in the ionized calcium/phosphorous level. Histology and immunohistochemistry revealed the successful transplantation of parathyroid tissues into the muscles in both groups. In conclusion, the PEG-PAF-based thermoreversible gel is a good candidate carrier material for intramuscular parathyroid autotransplantation.

Usefulness of radiologic examinations for diagnosing level VI lymph node metastasis in patients with laryngohypopharyngeal carcinoma.

The aim of this study was to estimate the usefulness of imaging modalities for diagnosing level VI lymph node metastasis in patients with laryngohypopharyngeal cancer. A retrospective review of 138 patients with squamous cell carcinoma of the larynx or hypopharynx who underwent central compartment neck dissection (CCND) was performed. Level VI metastasis occurred in 29 of 138 (21 %) patients. CT accuracy and sensitivity for level VI lymph node was 85.5 and 48.3 %, respectively. Respective values for MRI, US, and PET were 84.4 and 41.4 %, 87.7 and 44.8 %, and 81.2 and 34.5 %. CT combined with US demonstrated the best result in sensitivity (51.7 %) and negative predictive value (NPV) (88.1 %) compared to those of other imaging techniques. CT combined with US could improve sensitivity and NPV compared to CT or US alone. Considering cost-effectiveness and the highest results in all parameters compared to those of other combinations of imaging techniques, CT combined with US could be the best preoperative imaging modalities for evaluating laryngohypopharyngeal cancer. However, these imaging techniques are not absolutely reliable methods for detecting occult metastasis in the level VI due to high false-negative rates. Elective CCND should be considered in indicated patients (>N2b, T4), even if physical examinations and the radiologic findings of level VI nodes are negative.

Development of hypoparathyroidism animal model and the feasibility of small intestinal submucosa application on the parathyroid autotransplantation.

The purpose of this study is to evaluate the feasibility of small intestinal submucosa (SIS) application on the parathyroid autotransplantation in a rat model of hypoparathyroidism. The rats were divided into four groups: NC (no procedure, n = 5), PTX (total parathyroidectomy, n = 6), PT (total parathyroidectomy and parathyroid autotransplantation, n = 10) and PT + SIS group (total parathyroidectomy and parathyroid autotransplantation with SIS, n = 10). The levels of parathyroid hormone (PTH), calcium, and phosphorous were measured on 0, 3, 7, 21, 56 and 84 days after surgery. PTH level was expressed as median (interquartile range) and histological and immunohistochemical examinations were performed. PTH levels were significantly decreased to "not detectable level" from day 3 in PTX group. PTH was not detected in both PT and PT + SIS groups on the 21st day. On the 56th day, PTH levels were increased in both groups: 3 out of 8 rats (37.5%) in the PT group, 6 out of 9 rats (66.7%) in the PT + SIS group. The PTH level was fully recovered to its preoperative range on the day 84 as 6 of 8 rats (75%) of the PT group and 7 of 9 rats (77.8%) of the PT + SIS group were recovered; the PTH levels were 117.84 and 178.36 pg/ml, respectively. The neo-vascularization was well observed around the parathyroid tissue, and the number of new vessels formed was higher in the PT + SIS group (15 vessels/high power field) as compared to the PT group (10 vessels/high power field). This study showed the feasibility and the treatment effect of SIS as the success rate of autotransplantation of parathyroid tissue was significantly increased without severe inflammatory response in hypothyroidism animal model.

Microbiomic association between the saliva and salivary stone in patients with sialolithiasis.

Salivary stones, known as sialoliths, form within the salivary ducts due to abnormal salivary composition and cause painful symptoms, for which surgical removal is the primary treatment. This study explored the role of the salivary microbial communities in the formation of sialoliths. We conducted a comparative analysis of microbial communities present in the saliva and salivary stones, and sequenced the 16S rRNA gene in samples obtained from patients with sialoliths and from healthy individuals. Although the diversity in the saliva was high, the essential features of the microbial environment in sialoliths were low diversity and evenness. The association of microbial abundance between stones and saliva revealed a positive correlation between Peptostreptococcus and Porphyromonas, and a negative correlation for Pseudomonas in saliva. The functional potential differences between saliva and stones Bacterial chemotaxis and the citrate cycle were negatively correlated with most genera found in salivary stone samples. However, the functions required for organic compound degradation did not differ between the saliva samples. Although some microbes were shared between the sialoliths and saliva, their compositions differed significantly. Our study presents a novel comparison between salivary stones and salivary microbiomes, suggesting potential preventive strategies against sialolithiasis.

A primary left atrial leiomyosarcoma mimicking myxoma: echocardiographic findings.

Echocardiography is the initial imaging modality to delineate the cardiac mass. Clinically echocardiographic information about morphology, location, motion and hemodynamic consequences of the tumor is very important for decision making in terms of additional imaging studies and treatment. We present a case of left atrial leiomyosarcoma masquerading as myxoma preoperatively and discuss the echocardiographic features for distinguishing leiomyosarcoma from a benign tumor, such as myxoma.

Three-dimensional CT with virtual bronchoscopy: a useful modality for bronchial foreign bodies in pediatric patients.

Bronchial foreign bodies (FB) in children are difficult to diagnose when there is no witness to the aspiration event. The experience with three-dimensional CT and virtual bronchoscopic reconstruction (3D-CTVB) was reviewed for the diagnosis of bronchial FB in pediatric patients in this study. A retrospective review of ten pediatric patients (M:F = 5:5) who underwent rigid bronchoscopy by one otolaryngologist for the impression of a bronchial FB, at a tertiary training hospital, from February 2006 to September 2010 is reported. All patients had a plain chest X-ray and 3D-CTVB. The physical, radiological and bronchoscopic findings of the patients were analyzed. The mean duration from the aspiration event to hospital evaluation was 7 days (0-21 days). Four patients (44%) had witnesses to the aspiration event. Hyperaeration of the affected lung was noted in nine patients (90%) on the plain chest X-ray. In all of the patients, the foreign body location, suspected on the preoperative 3D-CTVB, was consistent with the intra-operative bronchoscopic findings. All FBs were successfully removed by rigid bronchoscopy without any complications. In conclusion, the 3D-CTVB was a very safe and useful diagnostic modality for bronchial FBs. The findings of this study suggest that the 3D-CTVB should be considered for the diagnosis of all patients with suspected bronchial FBs.

Development of Surgically Transplantable Parathyroid Hormone-Releasing Microbeads.

Hypoparathyroidism is an endocrine disorder that occurs because of the inability to produce parathyroid hormone (PTH) effectively. Previously, we reported the efficacy of tonsil-derived mesenchymal stem cells (TMSCs) differentiated into parathyroid-like cells for the treatment of hypoparathyroidism. Here, we investigated the feasibility of three-dimensional structural microbeads fabricated with TMSCs and alginate, a natural biodegradable polymer, to treat hypoparathyroidism. Alginate microbeads were fabricated by dropping a 2% (w/v) alginate solution containing TMSCs into a 5% CaCl2 solution and then differentiated into parathyroid-like cells using activin A and sonic hedgehog for 7 days. The protein expression of PTH, a specific marker of the parathyroid gland, was significantly higher in differentiated alginate microbeads with TMSCs (Al-dT) compared with in undifferentiated alginate microbeads with TMSCs. For in vivo experiments, we created the hypoparathyroidism animal model by parathyroidectomy (PTX) and implanted alginate microbeads in the dorsal interscapular region. The PTX rats with Al-dT (PTX+Al-dT) showed the highest survival rate and weight change and a gradual increase in serum intact PTH levels. We also detected a higher expression of PTH in retrieved tissues of PTX+Al-dT using immunofluorescence analysis. This study demonstrates that alginate microbeads are potential a new tool as a surgically scalable therapy for treating hypoparathyroidism.

Care and Management of Voice Change in Thyroid Surgery: Korean Society of Laryngology, Phoniatrics and Logopedics Clinical Practice Guideline.

Voice change is a common complaint after thyroid surgery and has a significant impact on quality of life. The Korean Society of Laryngology, Phoniatrics and Logopedics assembled a task force to establish guideline recommendations on education, care, and management related to thyroid surgery. The guideline recommendations encompass preoperative voice education, management of anticipated voice change during surgery, and comprehensive voice care after thyroid surgery, and include in-depth information and up-to-date knowledge based on validated literature. The committee constructed 14 key questions (KQs) in three categories-preoperative (KQ 1-2), intraoperative (KQ 3-8), and postoperative (KQ 9-14) management-and developed 18 evidence-based recommendations. The Delphi survey reached an agreement on each recommendation. A detailed evidence profile is presented for each recommendation. The level of evidence for each recommendation was classified as high-quality, moderate-quality, or low-quality. The strength of each recommendation was designated as strong or weak considering the level of evidence supporting the recommendation. The guidelines are primarily targeted toward physicians who treat thyroid surgery patients and speech-language pathologists participating in patient care. These guidelines will also help primary care physicians, nurses, healthcare policymakers, and patients improve their understanding of voice changes and voice care after thyroid surgery.

Porcine Tracheal Mucosa-Derived Decellularized Patch to Prevent Septal Perforation in a Rabbit Model.

BACKGROUND: Nasal septal perforation is caused by bilateral septal mucosal injuries resulting from nasal trauma and septal surgeries. Previous studies have reported that biocompatible materials may be effective for repairing nasal septal perforations. However, they were primarily used for treatment; no study has investigated their use for prevention of nasal septal perforation. OBJECTIVE: To determine whether porcine tracheal mucosa-derived decellularized patch can prevent the progression of nasal mucosa injuries to septal perforations. METHODS: Bilateral nasal septal mucosal defects were surgically induced in 36 rabbits. Silastic sheets were applied bilaterally in all rabbits, and decellularized mucosal patch was applied unilaterally (n = 12) or bilaterally (n = 12) at the defect site in the respective experimental groups. Between 1 and 8 weeks postoperatively, the animals were sacrificed, and their nasal septa were completely removed. The excised septa were examined macroscopically and microscopically (histopathological examinations). Moreover, glycosaminoglycan (GAG) estimations of the septa were performed to evaluate mucosal regeneration and mechanical properties. RESULTS: Septal perforations occurred in 5 animals in the control group (5/12; 42%), 1 in the unilateral group (1/12; 9%), and in none in the bilateral group. Compared with the control group, the experimental groups showed significantly different mucosal and cartilage regeneration. CONCLUSION: Decellularized porcine tracheal mucosa can prevent mucosal defects from progressing to septal perforation, promote the repair of mucosal defects, and protect the nasal cartilage.

3D QSAR studies on 3,4-dihydroquinazolines as T-type calcium channel blocker by comparative molecular similarity indices analysis (CoMSIA).

A comparative molecular similarity indices analysis (CoMSIA) of a set of 42 3,4-dihydroquinazolines have been performed to find out the pharmacophore elements for T-type calcium channel blocking activity. The most potent compound, 33 (KYS05090) was used to align the molecules. As a result, we obtained 3D QSAR model which provided good predictivity for the training set (q(2)=0.642, r(2)=0.874) and the test set (r(pred)(2)=0.884). This model would guide the design of new chemical entities potentially having high potency.

Antitumor activity of 3,4-dihydroquinazoline dihydrochloride in A549 xenograft nude mice.

In the previous article we have reported that 3,4-dihydroquinazoline 1 is a potent and selective T-type calcium channel blocker that exhibited strong anti-cancer activity in vitro. Compound 1·2HCl was further in vivo evaluated against A549 xenograft in BALB/c nude mice, which exhibited 49% tumor-weight inhibition through intravenous administration of 2 mg/kg of body weight and was more potent than doxorubicin. Moreover, compound 1·2HCl has an oral bioavailability of 98% with LD(50) values of 693 mg/kg (p.o. route) and 40.0 mg/kg (i.v. route) of body weight. In addition, its efficient scale-up synthetic method was developed.

Dietary factors associated with inflammatory laryngeal disease in South Korea.

Laryngeal inflammation causes not only benign diseases of the larynx, such as laryngitis and granuloma, but also malignancy. Dietary factors are known to control or modulate the inflammatory reaction in the body. To date, the association between laryngeal inflammation and dietary factors has not been reported using nationwide population-based data. The aim of this study was to analyze the association between several dietary factors and inflammatory laryngeal disease in the Korean population. This study analyzed the data from Korean National Health and Nutrition Examination Surveys which is cross-sectional nationwide-population-based study. Association between the dietary nutrient intake and the prevalence of inflammatory laryngeal diseases was analyzed in 21,116 participants who underwent a laryngoscopy and filled in the dietary intake questionnaires. Of the 21,116 participants included in the analysis, 758 (3.59%) were diagnosed with inflammatory laryngeal disease. Prevalence of inflammatory laryngeal disease was higher in men (4.58%) than in women (2.84%). The mean age of patients was 53.77 years. When analyzing the risk using propensity score matching, ILD group tend to consume more coffee and to intake less fiber and iron than normal group. On Logistic regression analysis, an increased intake of carbohydrate, fiber, and iron was associated with lowered risk of having ILD in female. The association between inflammatory laryngeal disease and dietary factors was prominent in the group aged ≥50 years and female. Increased intake of fiber, iron, and vitamin A were associated with lower risk in the group aged ≥50 years. In female, increased intake of fiber, iron were associated with lower risk of having ILD. In the group aged ≤50 years, only an increased consumption of makgeolli, Korean traditional rice wine, was associated with a higher risk of ILD.

Development of Acellular Respiratory Mucosal Matrix Using Porcine Tracheal Mucosa.

BACKGROUND: Respiratory mucosa defects result in airway obstruction and infection, requiring subsequent functional recovery of the respiratory epithelium. Because site-specific extracellular matrix (ECM) facilitates restoration of organ function by promoting cellular migration and engraftment, previous studies considered decellularized trachea an ideal ECM; however, incomplete cell removal from cartilage and mucosal-architecture destruction are frequently reported. Here, we developed a decellularization protocol and applied it to the respiratory mucosa of separated porcine tracheas. METHODS: The trachea was divided into groups according to decellularization protocol: native mucosa, freezing-thawing (FT), FT followed by the use of Perasafe-based chemical agents before mucosal separation (wFTP), after mucosal separation (mFTP), and followed by DNase decellularization (mFTD). Decellularization efficacy was evaluated by DNA quantification and hematoxylin and eosin staining, and ECM content of the scaffold was evaluated by histologic analysis and glycosaminoglycan and collagen assays. Biocompatibility was assessed by cell-viability assay and in vivo transplantation. RESULTS: The mFTP mucosa showed low antigenicity and maintained the ECM to form a proper microstructure. Additionally, tonsil-derived stem cells remained viable when cultured with or seeded onto mFTP mucosa, and the in vivo host response showed a constructive pattern following implantation of the mFTP scaffolds. CONCLUSION: These results demonstrated that xenogenic acellular respiratory mucosa matrix displayed suitable biocompatibility as a scaffold material for respiratory mucosa engineering.

Trends in the Incidence and Treatment of Benign Vocal Fold Lesions in Korea, 2006-2015: A Nationwide Population-based Study.

OBJECTIVE: The aim of this study was to determine the prevalence and demographics of benign vocal fold lesions (BVFL) and trends in its treatment in Korea based on data collected from the National Health Insurance Service database. MATERIAL AND METHODS: Data for patients diagnosed with BVFL (ICM-10 codes J381, J382, J384) from 2006 to 2015 were selected for analysis. Patient characteristics, including sex, age, income, area of residence, and comorbidity, were analyzed. Treatment was divided into surgical management and conservative management using operation codes. RESULTS: The prevalence and incidence of BVFL increased from 7.07% and 5.29%, respectively, in 2006 to 12.47% and 7.98% in 2015. Compared with the non-BVFL population, patients with BVFL were more likely to be female, reside in an urban area, and have gastroesophageal reflux disease. There was no significant change in the incidence of surgical treatment during the study period (around 6000 per year); however, the surgical treatment rate decreased from 19.29% to 8.38%. The probability of undergoing surgical treatment for BVFL was higher in men, those aged 50-59 years, and those in the lowest quartile for income, except for the medical aid group. CONCLUSION: In Korea, there was an increase in the number of patients diagnosed with BVFL and a decrease in the operation rate for this condition between 2006 and 2015. Diagnosis of BVFL varied significantly based on income and sex; however, the only variable affecting the operation rate was patient age.

A 3D-printed polycaprolactone/ß-tricalcium phosphate mandibular prosthesis: A pilot animal study.

OBJECTIVE: In this study, we assessed the effectiveness of a tonsil-derived mesenchymal stem cell (TMSC)-transplanted polycaprolactone/beta-tricalcium phosphate prosthesis (specifically designed for easier fixing and grafting with a single scaffold) on rabbit mandible osteogenesis. METHODS: The mandibles of 18 rabbits were exposed, and 10 × 8-mm bone defects were made. Two rabbits did not receive implants; four were reconstructed with the scaffold control (SC) (SC group); four were reconstructed with scaffolds soaked in peripheral blood (PB) (PB group); four were reconstructed with TMSC-transplanted scaffolds (TMSC group); and four were reconstructed with differentiated osteocyte-transplanted scaffolds (DOC) (DOC group). Each rabbit was sacrificed 12 weeks after surgery, and the area of new bone formation was investigated by mechanical testing, histology, and micro-computed tomography. RESULTS: More extended and denser new bone masses were observed in the TMSC and DOC groups, although fibrosis and vascular formation levels were similar in all groups, suggesting that the dual-structured scaffold alone provides a good environment for bone attachment and regeneration. The bone volumes of representative scaffolds from the SC, PB, TMSC, and DOC groups were 43.12, 48.35, 53.10, and 57.44% of the total volumes, respectively. CONCLUSION: The design of the scaffold resulted in effective osteogenesis, and TMSCs showed osteogenic potency, indicating that their combination could enable effective bone regeneration. LEVEL OF EVIDENCE: NA Laryngoscope, 130:358-366, 2020.

Fabrication and characterization of 3D-printed elastic auricular scaffolds: A pilot study.

OBJECTIVE: Aesthetic reconstruction of the external ear is challenging due to the complex anatomical shape of the auricle. Recently, artificial scaffolds such as Medpor (Stryker, Kalamasoo, MI, USA) have become widely used in ear reconstruction. However, the Medpor scaffold is stiffer than the natural ear, which may lead to discomfort, and moreover has uniform design for every patient. In this study, we investigated whether three-dimensional (3D)-printed artificial polyurethane (PU) scaffolds are suitable for auricular reconstruction. METHODS: PU scaffolds were fabricated using 3D printing according to a design derived from a digital imaging and communications in medicine (DICOM) image of the human auricle. The microstructure of the scaffolds was observed using scanning electron microscopy, and the porosity was examined. Cell proliferation on the scaffolds was assessed in vitro using tonsil-derived mesenchymal stem cells to evaluate the biocompatibility of the scaffolds. The scaffolds were implanted in C57BL/6 mice, and histological analysis was performed. RESULTS: The structural study revealed that the 3D-printed porous PU scaffolds have rectangular microstructure with regular pitch and line, as well as high porosity (56.46% ± 10.22%) with a pore diameter of 200 µm. The mechanical properties of the 3D-printed PU scaffolds were similar to those of the human auricle cartilage. Cell proliferation on the PU scaffolds was greater than that on Medpor scaffolds. Histological evaluation demonstrated that the porous parts of the PU scaffolds became filled with collagen and vascular tissue. CONCLUSION: Elastic, porous PU scaffolds can be obtained using 3D printing, have biomechanical properties similar to those of the natural ear, and are suitable for use in auricular reconstruction. LEVEL OF EVIDENCE: NA Laryngoscope, 129:351-357, 2019.

Tonsil-derived stem cells as a new source of adult stem cells.

Located near the oropharynx, the tonsils are the primary mucosal immune organ. Tonsil tissue is a promising alternative source for the high-yield isolation of adult stem cells, and recent studies have reported the identification and isolation of tonsil-derived stem cells (T-SCs) from waste surgical tissue following tonsillectomies in relatively young donors (i.e., under 10 years old). As such, T-SCs offer several advantages, including superior proliferation and a shorter doubling time compared to bone marrow-derived mesenchymal stem cells (MSCs). T-SCs also exhibit multi-lineage differentiation, including mesodermal, endodermal (e.g., hepatocytes and parathyroid-like cells), and even ectodermal cells (e.g., Schwann cells). To this end, numbers of researchers have evaluated the practical use of T-SCs as an alternative source of autologous or allogenic MSCs. In this review, we summarize the details of T-SC isolation and identification and provide an overview of their application in cell therapy and regenerative medicine.

Synthesis and SAR study of T-type calcium channel blockers. Part II.

3,4-Dihydroquinazoline derivatives have been known to be the novel and potent T-type calcium channel blockers. From a systematic variation of 3,4-dihydroquinazoline derivative 5c (KYS05043), plausible SAR results were established. It was revealed that a 5-(dimethylamino)pentylamino group at R(1), a biphenyl group at R(2), and a benzyl amido group at R(3)in the 3,4-dihydroquinazoline backbone are closely related with the channel selectivity (T/N-type) as well as the potency based on the discovery of 6k (KYS05090).