An Examination of Melanoma Detection and Characteristics at a Nova Scotia Tertiary Care Centre, From 2015-2019.

BACKGROUND: Melanoma is one of the most common cancers in Canada,1 with the highest incidence in Nova Scotia (NS). OBJECTIVES: To describe the demographics, lesion characteristics, and diagnostic accuracy of suspected melanomas excised at the largest center in NS. METHODS: The dermatopathology database was interrogated for cases of possible melanoma from 2015 through 2019. Age, gender, site of lesion, pathologic diagnosis, Breslow depth, and equivocal pathology were assessed. RESULTS: 984 lesions had a clinical diagnosis of possible melanoma, identifying 301 melanomas. Of these, 142 (47%) were melanoma in situ (MIS) which in females occurred mostly on the extremities, while in males the head predominated. For invasive melanoma (IM), the extremities remained predominant for women, while the back was most common in men. Lower extremity lesions were more likely to be invasive and female patients were more likely to present with them at a younger age compared to males. The pathology was challenging for 23.94% of MIS, and 16.18% of IM. A mean of 3.1 lesions were excised for every melanoma identified. CONCLUSIONS: Early diagnosis of melanoma is challenging clinically and pathologically. Our melanoma detection rate was 31%, with an increasing trend in the proportion of MIS, and decreasing trend in the proportion of IM over the years. Almost 50% of melanomas were detected in early stages, supporting positive outcomes. Melanomas were more common on extremities in females and the back in males. Melanomas on the lower limbs were more likely to be invasive regardless of gender.

QT prolongation, torsades de pointes, and sudden death with short courses of chloroquine or hydroxychloroquine as used in COVID-19: A systematic review.

Chloroquine and hydroxychloroquine are now being widely used for treatment of COVID-19. Both medications prolong the QT interval and accordingly may put patients at increased risk for torsades de pointes and sudden death. Published guidance documents vary in their recommendations for monitoring and managing these potential adverse effects. Accordingly, we set out to conduct a systematic review of the arrhythmogenic effect of short courses of chloroquine or hydroxychloroquine. We searched on MEDLINE and Embase, as well as in the gray literature up to April 17, 2020, for the risk of QT prolongation, torsades, ventricular arrhythmia, and sudden death with short-term chloroquine and hydroxychloroquine usage. This search resulted in 390 unique records, of which 41 were ultimately selected for qualitative synthesis and which included data on 1515 COVID-19 patients. Approximately 10% of COVID-19 patients treated with these drugs developed QT prolongation. We found evidence of ventricular arrhythmia in 2 COVID-19 patients from a group of 28 treated with high-dose chloroquine. Limitations of these results are unclear follow-up and possible publication/reporting bias, but there is compelling evidence that chloroquine and hydroxychloroquine induce significant QT-interval prolongation and potentially increase the risk of arrhythmia. Daily electrocardiographic monitoring and other risk mitigation strategies should be considered in order to prevent possible harms from what is currently an unproven therapy.

Fabrication of thin-layer matrigel-based constructs for three-dimensional cell culture.

Extracellular matrix-based hydrogels such as Matrigel are easy-to-use, commercially available, and offer environments for three-dimensional (3-D) cell culture that mimic native tissue. However, manipulating small volumes of these materials to produce thin-layer 3-D culture systems suitable for analysis is difficult because of air-liquid-substrate interfacial tension effects and evaporation. Here, we demonstrate two simple techniques that use standard liquid-handling tools and nontreated 96-well plates to produce uniform, thin-layer constructs for 3-D culture of cells in Matrigel. The first technique, the floating 3-D cell culture method, uses phase-separating polymers to form a barrier between the dispensed Matrigel, air, and cultureware surface to generate consistently thin hydrogels from volumes as low as 5 µL. These unanchored gels provide a useful assay for investigating airway smooth muscle cell contraction and may have future applications in studying asthma pathophysiology. The second technique, the fixed 3-D cell culture method, provides an anchored gel system for culturing noncontractile cells (e.g., neurons) where 20 µL of Matrigel is dispensed into the bottom of a well filled with culture medium to form a thin gel containing embedded cells. This technique has potential widespread applications as an accessible 3-D culture platform for high-throughput production of disease models for evaluation of novel drug therapies. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2733, 2019.

Spirometric reference equations for healthy children aged 6 to 11 years in Taiwan.

BACKGROUND: Spirometry is a valuable technique for evaluating pulmonary function, but there were few normative reference values for young children in Taiwan, and none for the last 10 years. The objective of our study was to establish updated reference values and equations for children aged 6-11 years in northern Taiwan. METHODS: A total of 309 healthy children (153 boys and 156 girls) were enrolled in the present study. The data of at least 3 trials for each child were collected, and the highest values analyzed. The analyzed pulmonary function parameters were focused on forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), forced expiratory flow between 25% and 75% expired volume (FEF25-75), and the ratio of FEV1/FVC. RESULTS: The results revealed that there were mostly no significant differences between boys and girls, and the standing height (H, cm) was the factor with the highest correlation with the pulmonary function parameters. Regression equations of the major pulmonary function parameters for both boys and girls were obtained: FVC = -2.690 + 0.0330H; FEV1 = -2.559 + 0.0311H; PEF = -300.231 + 3.938H; FEF25-75 = -3.218 + 0.0425H (p < 0.001). CONCLUSION: Our study determined the updated normative values and reference equations for Chinese children aged 6-11 years living in northern Taiwan. These values can be used as normative reference values to evaluate pulmonary function in diseased children with the same ethnicity and lifestyle.

Spirometric pulmonary function parameters of healthy Chinese children aged 3-6 years in Taiwan.

Spirometry is a well-known technique for evaluating pulmonary function, but few studies have focused on preschool children. The aim of this study was to determine reference values of forced spirometric parameters in young Chinese children, aged 3-6 years, in Taiwan. Spirometric measurements were performed at day care centers by experienced pediatricians. Of 248 children without a history of chronic respiratory illness, at least two valid spirometric attempts were obtained from 214 children (109 boys and 105 girls; age: 36-83 [mean = 61] months; height: 90-131 [mean = 111] cm). Values of forced expiratory volume in 1 sec (FEV1) and 0.5 sec (FEV(0.5)), forced vital capacity (FVC), peak expiratory flow rate (PEF), forced expiratory between 25% and 75% FVC (FEF(25-75)), and forced expiratory flow rate at 25%, 50%, and 75% of FVC (FEF(25), FEF(50), and FEF(75)) were derived and analyzed. There were significant positive correlations between study parameters and body height, body weight, and age. Height was the most consistently correlated measurement in both boys and girls. Although boys tended to have higher spirometric values than girls, we found significant differences only in FVC and FEV1 between boys and girls aged 6 years. The regression equations of each parameter were obtained. In conclusion, spirometric pulmonary function tests are feasible in 3- to 6-year-old children. The obtained values and regression equations provide a reference for Chinese preschool children and may be of value in evaluating pulmonary function of children with respiratory problems in this age group.

Chaotic communication in radio-over-fiber transmission based on optoelectronic feedback semiconductor lasers.

Performance of chaotic communication in radio-over-fiber (ROF) transmission based on optoelectronic feedback semiconductor lasers is studied numerically. The chaotic carrier is generated by optoelectronic feedback semiconductor lasers, where chaotic communication is realized by synchronizing a receiver laser with a transmitter laser. Transmission quality of different message encoding schemes, including additive chaos modulation (ACM) and on-off shift keying (OOSK), are investigated and compared. In this study, the dispersion and nonlinearity effects in the fiber transmission module and the amplified spontaneous emission noise from the optical amplifiers are considered. In the wireless channel, effects of additive white Gaussian noise, multipath, and path loss are included. To quantitatively study the performance of this chaotic communication system in the ROF transmission, bit-error-rates (BER) of different transmission lengths, message bit-rates, and signal-to-noise ratios are studied. The optimal launched power and message strength that minimize the BER while assuring effective communication security are discussed. While the ACM scheme is shown to perform better in a fiber only configuration, the OOSK scheme shows better immunity to the random effects and waveform distortions presented in the wireless channel.