A Transfer Function Model Development for Reconstructing Radial Pulse Pressure Waveforms Using Non-Invasively Measured Pulses by a Robotic Tonometry System.

The primary goal of this study is to develop a mathematical model that can establish a transfer function relationship between the "external" pulse pressures measured by a tonometer and the "internal" pulse pressure in the artery. The purpose of the model is to accurately estimate and rebuild the internal pulse pressure waveforms using arterial tonometry measurements. To develop and validate a model without human subjects and operators for consistency, this study employs a radial pulse generation system, a robotic tonometry system, and a write model with an artificial skin and vessel. A transfer function model is developed using the results of the pulse testing and the mechanical characterization testing of the skin and vessel. To evaluate the model, the pulse waveforms are first reconstructed for various reference pulses using the model with tonometry data. They are then compared with pulse waveforms acquired by internal measurement (by the built-in pressure sensor in the vessel) the external measurement (the on-skin measurement by the robotic tonometry system). The results show that the model-produced pulse waveforms coinciding well with the internal pulse waveforms with small relative errors, indicating the effectiveness of the model in reproducing the actual pulse pressures inside the vessel.

Magnetorheological Fluid Haptic Shoes for Walking in VR.

In this article, present RealWalk, a pair of haptic shoes for HMD-based VR, designed to create realistic sensations of ground surface deformation, and texture using Magnetorheological fluid (MR fluid). RealWalk offers a novel interaction scheme through the physical interaction between the shoes, and the ground surfaces while walking in VR. Each shoe consists of two MR fluid actuators, an insole pressure sensor, and a foot position tracker. The MR fluid actuators are designed in the form of multi-stacked disc structure with a long flow path to maximize the flow resistance. With changing the magnetic field intensity in MR fluid actuators based on the ground material in the virtual scene, the viscosity of MR fluid is changed accordingly. When a user steps on the ground with the shoes, the two MR fluid actuators are pressed down, creating a variety of ground material deformation such as snow, mud, and dry sand. We built an interactive VR application, and compared RealWalk with vibrotactile-based haptic shoes in four different VR scenes: grass, sand, mud, and snow. We report that, compared to vibrotactile-haptic shoes, RealWalk provides higher ratings in all scenes for discrimination, realism, and satisfaction. We also report qualitative user feedback for their experiences.

Tumor growth rate as a prognostic factor of acral melanoma in a Korean population.

Rapid growth of cutaneous melanoma is associated with aggressive histopathologic features and poor prognosis. However, the impact of growth rate (GR) in acral melanoma (AM) remains largely unknown.We performed this study to identify the impact of GR on lymph node metastasis and survival in AM.We analyzed cases of invasive AM diagnosed at our institution between 1998 and 2017. We investigated the impact of GR on the prognosis of AM.A total of 126 cases of invasive AM were included. Log (GR) was significant associated with lymph node metastasis in the univariate logistic regression analysis (P = .005). The log-rank test revealed statistically significant differences in disease-free survival (DFS) and disease-specific survival (DSS) among the GR quartiles. In the Cox regression analysis, log (GR) was an independent predictor for DFS (P = .041), but not for DSS in multivariate analysis. In the subgroup analysis, log (GR) was an independent predictor for early-stage (≤2A) AM (DFS, P = .002; DSS, P = .004).The limitations of this study include the retrospective design of the study and possible recall bias.Our results suggest that GR is an important prognostic factor for DFS and DSS in AM patients and an independent predictor for early-stage AM.

Adiponectin-Based Peptide (ADP355) Inhibits Transforming Growth Factor-ß1-Induced Fibrosis in Keloids.

Keloids, benign cutaneous overgrowths of dermal fibroblasts, are caused by pathologic scarring of wounds during healing. Current surgical and therapeutic modalities are unsatisfactory. Although adiponectin has shown an antifibrotic effect, its large size and insolubility limit its potential use in keloid treatment. We investigated the effect of a smaller and more stable adiponectin-based peptide (ADP355) on transforming growth factor ß1 (TGF-ß1)-induced fibrosis in a primary culture of keloid fibroblasts prepared from clinically obtained keloid samples. Xenograft of keloid tissues on athymic nude mice was used to investigate the effect of intralesional injection of ADP355. ADP355 significantly attenuated the TGF-ß1-induced expression of procollagen type 1 in keloid fibroblasts (p < 0.05). Moreover, it inhibited the TGF-ß1-induced phosphorylation of SMAD3 and ERK, while amplifying the phosphorylation of AMP-activated protein kinase (p < 0.05). Knockdown of adiponectin receptor 1 reversed the attenuation of procollagen expression in ADP355-treated TGF-ß1-induced fibrosis (p < 0.05). ADP355 also significantly reduced the gross weight and procollagen expression of keloid tissues in xenograft mice compared to control animals. These results demonstrate the therapeutic potential of the adiponectin peptide ADP355 for keloids.

Functional surgery versus amputation for in situ or minimally invasive nail melanoma: A meta-analysis.

BACKGROUND: Evidence on whether functional surgery is not inferior to amputation for the treatment of in situ or minimally invasive (Breslow thickness ≤0.5 mm) nail melanoma is limited. OBJECTIVE: To investigate the difference in local recurrence between the 2 interventions for in situ or minimally invasive nail melanoma using available published studies. METHODS: We performed systematic search on PubMed, Embase, Cochrane Library, trial registers, and grey literature databases from inception to June 28, 2018. We included observational studies with at least 5 patients with in situ or minimally invasive nail melanoma. Main outcome was local recurrence. RESULTS: The odds ratio synthesized from 5 studies including 109 patients (88 functional operations and 21 amputations) was 1.57 (95% confidence interval, 0.31-8.00). LIMITATIONS: Small sample size and possible interstudy heterogeneity. CONCLUSIONS: Our meta-analysis revealed no difference in local recurrence between the 2 interventions. Considering the functional deficit after amputation, conservative surgery should be the treatment of choice for in situ or minimally invasive nail melanoma.

Local recurrence and metastasis in patients with malignant melanomas after surgery: A single-center analysis of 202 patients in South Korea.

Malignant melanoma (MM) is a lethal skin cancer in Western countries. Although the incidence is low in Asians compared to that in Caucasians, it is increasing. However, literature regarding risk factors for prognosis of MM patients who have undergone surgical excision in Asian is limited. This study aimed to investigate the predictive factors for local recurrence and metastasis in MM patients who underwent surgical treatment at a single tertiary-level hospital in Korea. Patients who underwent surgery for MM at our institution between January 1998 and December 2014 were analyzed. We retrospectively investigated risk factors for local recurrence and metastasis after surgery. In cases with distant metastasis, tumor thickness (adjusted Hazard Ratio (HR), 6.139; 95% confidence interval (CI), 2.152 to 17.509; P = 0.001) and increased mitotic number [(0-1/mm2 vs 2-6/mm2: adjusted HR, 4.483; 95% CI, 1.233 to 16.303; P = 0.023); (0-1/mm2 vs > 6/mm2: adjusted HR, 10.316; 95% CI, 2.871 to 37.063; P < 0.001)] were associated with risk in multivariate analysis. Regarding local recurrence, tumor thickness (T4 [≥4mm] vs T1) was found to be a significant risk factor (adjusted HR, 8.461; 95% CI, 2.514 to 28.474; P = 0.001). Our data revealed tumor thickness and increased mitotic count were significant risk factors for local recurrence and distant metastasis in Korean patients with MM after surgery.

Early detection of acral melanoma: A review of clinical, dermoscopic, histopathologic, and molecular characteristics.

Acral lentiginous melanoma is a distinct subtype of melanoma on acral skin. Patient presentation at later stages and delayed diagnosis by physicians contribute to a worse associated prognosis and survival rate. Despite our progress in understanding the key features of this disease, the diagnosis of early-stage acral melanoma is still challenging. It is essential to integrate clinical, dermoscopic, and histologic findings in the diagnosis of acral lentiginous melanoma. In addition, molecular studies can be helpful. In this review, we have summarized our current understanding of this disease entity from articles that were published between 1969 and 2018. We have outlined clinical and dermoscopic features as well as pathologic and molecular findings regarding acral melanoma and have presented an algorithm for diagnosis. Understanding and integrating these characteristics may assist clinicians in the early detection of acral melanomas.

A compact pulsatile simulator based on cam-follower mechanism for generating radial pulse waveforms.

BACKGROUND: There exists a growing need for a cost-effective, reliable, and portable pulsation simulator that can generate a wide variety of pulses depending on age and cardiovascular disease. For constructing compact pulsation simulator, this study proposes to use a pneumatic actuator based on cam-follower mechanism controlled by a DC motor. The simulator is intended to generate pulse waveforms for a range of pulse pressures and heart beats that are realistic to human blood pulsations. METHODS: This study first performed in vivo testing of a healthy young man to collect his pulse waveforms using a robotic tonometry system (RTS). Based on the collected data a representative human radial pulse waveform is obtained by conducting a mathematical analysis. This standard pulse waveform is then used to design the cam profile. Upon fabrication of the cam, the pulsatile simulator, consisting of the pulse pressure generating component, pressure and heart rate adjusting units, and the real-time pulse display, is constructed. Using the RTS, a series of testing was performed on the prototype to collect its pulse waveforms by varying the pressure levels and heart rates. Followed by the testing, the pulse waveforms generated by the prototype are compared with the representative, in vivo, pulse waveform. RESULTS: The radial Augmentation Index analysis results show that the percent error between the simulator data and human pulse profiles is sufficiently small, indicating that the first two peak pressures agree well. Moreover, the phase analysis results show that the phase delay errors between the pulse waveforms of the prototype and the representative waveform are adequately small, confirming that the prototype simulator is capable of simulating realistic human pulse waveforms. CONCLUSIONS: This study demonstrated that a very accurate radial pressure waveform can be reproduced using the cam-based simulator. It can be concluded that the same testing and design methods can be used to generate pulse waveforms for other age groups or any target pulse waveforms. Such a simulator can make a contribution to the research efforts, such as development of wearable pressure sensors, standardization of pulse diagnosis in oriental medicine, and training medical professionals for pulse diagnosis techniques.

Analysis of Clinical Features and Treatment Outcomes Using 1,064-nm Nd-YAG Laser with Topical Hydroquinone in Patients with Riehl's Melanosis: A Retrospective Study in 10 Patients.

BACKGROUND: Hyperpigmentation on the face and neck can be a devastating psychological burden in patients with Riehl's melanosis. However, successful treatment of the disease is challenging for clinicians. OBJECTIVE: To evaluate the effectiveness and safety of low-fluence neodymium-doped yttrium aluminum garnet (Nd:YAG) laser in the treatment of Riehl's melanosis and to identify prognostic factors determining the response to laser treatment. METHODS: We enrolled 10 Korean patients with Riehl's melanosis. The patients received 10~28 treatment sessions at 3-week intervals with low-fluence Nd:YAG laser. RESULTS: Among all the patients, seven reached near total improvement, and two and one patient reached marked improvement and minimal improvement, respectively, after low-fluence Nd:YAG laser treatment. The mean number of needed laser treatment sessions to reach marked improvement and near total improvement was 12.1±4.0 (ranged from 6 to 17) and 14.6±4.4 (ranged from 9 to 20), respectively. A further analysis revealed the proportion of patients who reached near total improvement was higher, and the mean number of necessary laser treatment sessions to reach minimal improvement was less in patients with dark brown pigmentation compared to those with light brown pigmentation. Among all patients, three complained of guttate hypopigmentation. However, the hypopigmented lesions spontaneously improved after the interruption of the treatment. CONCLUSION: We found that low-fluence Nd:YAG laser is an effective and safe treatment modality for Riehl's melanosis.

Congenital Dermal Melanocytosis on the Foot: A Case Report and Review of the Literature.

Dermal melanocytosis is a common pigmented skin disease, characterized by an increased number of ectopic melanocytes in the dermis. Rare variants of dermal melanocytosis that do not belong to these four typical groups-nevus of Ota, nevus of Ito, blue nevus, and Mongolian spots-are called dermal melanocyte hamartoma, or congenital dermal melanocytosis (CDM) as it mostly appears from birth. We report a case of CDM on the foot of a young woman with a literature review of previously reported cases of CDM.

Analysis of Judicial Precedents Cases Regarding Skin Cancer from 1997 to 2017 in Republic of Korea.

BACKGROUND: Both medical disputes and the incidence of skin cancer are increasing in Korea. OBJECTIVE: The aim of this study was to figure out the medical litigation related to skin cancer and propose a method to prevent the medical disputes. METHODS: Skin cancer-related judgments were searched by The Supreme Court of Korea's Written Judgment Management System based on the keywords for skin cancer. The search system included sentenced cases at the Lower Courts, the Appellate Courts, and the Supreme Court from 1997 to 2017. RESULTS: Seven cases were selected as the litigation cases related to skin cancer. Four cases (57.1%) presented malignant melanoma, while the rest presented squamous cell carcinoma, metastatic skin cancer, and peripheral T cell lymphoma (1 case in each). Four cases resulted in death from cancer metastasis, and 3 cases presented as sequelae. The legal issues related to the medical disputes could be categorized as follows: misdiagnosis, delayed diagnosis, performance error, and lack of informed consent. Delayed diagnosis and lack of informed consent were the most common issues (n=4) in the precedents. Five cases (71.4%) were sentenced the awarded amounts to the plaintiff, including 2 cases of settlement decision. The average awarded amount was 42,553,644±27,567,455 Korean won. CONCLUSION: Physicians should pay attention to the cases of the skin cancer to prevent medical malpractice and disputes. The practices pertaining to proper diagnosis, treatment plans, and obtaining an informed consent should be followed during the course of treating skin cancer.

Squamous cell carcinoma of the nail unit: a retrospective review of 19 cases in Asia and comparative review of Western literature.

BACKGROUND: Reports regarding squamous cell carcinoma of the nail unit (SCCnu) are rare in Asia. OBJECTIVES: To investigate the features of SCCnu in the Asian population. METHOD: We performed a retrospective review of patients diagnosed with SCCnu at our institution between 2012 and 2017. RESULTS: Nineteen cases were included. Thirteen patients were male (68.4%). The fingers were most frequently affected (73.7%). Mean delay to diagnosis was 62.4 months. Misdiagnosis rate was high (78.9%). Frequent clinical features were subungual tumor, subungual hyperkeratosis, nail dystrophy, ulcer, and nail loss. The majority of cases were invasive SCC in 15 cases (78.9%), while SCC in situ was found in four cases (21.1%). Local recurrence was detected in two cases (10.5%) following surgical resection. However, distant metastasis was not reported. CONCLUSION: This study provides data of 19 SCCnu cases in Asia. Clinical characteristics of SCCnu in this study were similar to those of reports from Western countries. However, we found a higher frequency of more invasive cases and longer delay to diagnosis in our study; this advocates the need for greater attention on nail disorders among healthcare providers, particularly in Asia.

Assessment of a Predictive Scoring Model for Dermoscopy of Subungual Melanoma In Situ.

Importance: Subungual melanoma in situ (SMIS) is a malignant neoplasm that requires early diagnosis and complete surgical excision; however, little is known about the usefulness of the detailed dermoscopic features of longitudinal melanonychia (LM) to predict the diagnosis of SMIS. Objectives: To investigate the characteristic dermoscopic findings of SMIS and to establish a predictive scoring model for the diagnosis of SMIS in patients with adult-onset LM affecting a single digit. Design, Setting, and Participants: A cohort study of 19 patients with biopsy-proven SMIS and 26 patients with benign LM diagnosed in a tertiary referral hospital in Seoul, South Korea, from September 1, 2013, to July 31, 2017. Main Outcomes and Measures: Patient demographics, frequency of specific dermoscopic findings, and a predictive scoring model. Results: Of the total 45 patients with pigmented nails, the 19 patients with SMIS included 14 women and had a mean (SD) age of 52.0 (14.4) years, and the 26 patients with benign LM included 18 women and had a mean (SD) age of 48.1 (13.2) years. Asymmetry (odds ratio [OR], 34.00; 95% CI, 3.88-297.70), border fading (OR, 9.33; 95% CI, 2.37-36.70), multicolor (OR, 11.59; 95% CI, 2.21-60.89), width of the pigmentation of at least 3 mm (OR, 5.31; 95% CI, 1.01-28.07), and presence of the Hutchinson sign (OR, 18.18; 95% CI, 2.02-163.52) were features of LM that were significantly associated with SMIS. A predictive scoring model incorporating these dermoscopic features of SMIS was assessed. The model, ranging from 0 to 8 points, showed a reliable diagnostic value (the receiver operating characteristic curve had an area under the curve [C statistic] of 0.91) in differentiating SMIS from benign LM at a cutoff value of 3, with a sensitivity of 89% and a specificity of 62%. Conclusions and Relevance: This study suggests characteristic dermoscopic features for SMIS. A predictive scoring model based on these morphologic features may help differentiate SMIS from benign LM.

Association between Breslow thickness and dermoscopic findings in acral melanoma.

BACKGROUND: Dermoscopy is a useful tool for the diagnosis of acral melanomas (AMs). However, little is known about the influence of tumor thickness on the dermoscopic findings of AM. OBJECTIVE: To investigate the affect Breslow thickness (BT) has on the dermoscopic patterns of AM. METHODS: Data on cases of AM on the glabrous skin were collected from 4 university hospitals. We investigated the frequency of each dermoscopic feature of AM according to the BT. Statistical analysis was performed to investigate the association between the specific dermoscopic patterns and BT. RESULTS: Multivariable analysis revealed that the colors red (odds ratio [OR] 16.482, 95% confidence interval [CI] 3.605-99.016); blue (OR 7.092; 95% CI 1.707-37.435); and white (OR 5.048, 95% CI 1.152-22.897) were more common in AM with BT >2 mm than those with BT ≤2 mm. Regarding patterns, atypical vascular (OR 34.589, 95% CI 6.458-305.852); blue-white veils (OR 9.605, 95% CI 1.971-72.062); and ulcers (OR 5.084, 95% CI 1.145-24.152) were more frequently detected in cases with BT >2 mm than those with BT ≤2 mm. LIMITATIONS: A retrospective study design and small sample size. CONCLUSION: This study showed an association between dermoscopic patterns and tumor thickness among patients with AM. Dermoscopy can be a useful adjuvant tool for predicting BT in AM.