Characterization of temporomandibular joint articular disc progenitor cell clones.

A critical component of the temporomandibular joint (TMJ) is the fibrocartilage articular disc (AD). Researchers have attempted to regenerate the AD to alleviate TMJ osteoarthritis but alternative cell sources for use in AD regenerative approaches are needed due to insufficient extracellular matrix (ECM) production by total articular disc cells (TACs). Tissue-specific progenitor cells have been identified in many tissues. The aim of the present study was to identify adult multipotent progenitor cells within the AD suitable for regenerative medicine applications. A novel AD progenitor cell population was identified in rhesus macaques. Clonally derived articular disc progenitor cells (ADPs) were isolated using fibronectin differential cell adhesion. ADPs represent between 1 and 3 % of the TAC population and are capable of in vitro expansion beyond 60 population doublings. ADPs were characterized using osteogenic, adipogenic, and fibrochondrogenesis differentiation assays. Clones exhibited phenotypic plasticity, differentiating into osteocytes, adipocytes, and fibrochondrocytes. ECM secretion profiles following fibrochondrogenic differentiation were assessed using immunohistochemistry (IHC), fluorescently activated cell sorting (FACS), total collagen, and glycosaminoglycan (GAG) assays and compared with TACs, articular cartilage progenitor cells (ACPs), tendon progenitor cells (TPCs) and bone-marrow-derived mesenchymal stem cells (BMMSCs). ADP pellet cultures produced a biochemical phenotype similar to native AD tissue, with production of versican (VCAN) and collagen types I, II, III, and VI (COL1, COL2, COL3, COL6). However, clonally derived ADP cell lines produced different amounts of ECM and exhibited different expansion potentials. These findings indicated flexibility in clone selection for potential regenerative strategies to recapitulate native anisotropy.

The Learning Curve of Third-Generation Percutaneous Chevron and Akin Osteotomy (PECA) for Hallux Valgus.

The learning curve to reach technical proficiency for third-generation percutaneous or minimally invasive chevron and Akin osteotomies (PECA/MICA) is recognized to be steep however it is poorly defined in the literature. This study is a retrospective review of the first 58 consecutive PECA cases of a single surgeon. The primary outcome was the number of cases required to reach technical proficiency as defined by the operation time. Secondary outcomes included radiation exposure, radiographic deformity correction, and complication rates. Between November 2017 and March 2019, 61 consecutive PECA cases were performed with outcome data available for 58 of these (95%). Technical proficiency was reached after 38 cases. Operation time and radiation exposure significantly decreased after this transition point (p < .05). There was no difference in complication rate or radiographic deformity correction regardless of position along the learning curve (p > .05). In conclusion, the mean number of cases required to reach technical proficiency in third-generation PECA is 38 cases. The complication rate does not correlate to the number of cases performed, therefore surgeons interested in learning minimally invasive surgery can be reassured that there is unlikely to be an additional risk of harm to a patient during the learning curve.

Miconazole and terbinafine induced reactive oxygen species accumulation and topical toxicity in human keratinocytes.

There are an estimated 1 billion cases of superficial fungal infection globally. Fungal pathogens form biofilms within wounds and delay the wound healing process. Miconazole and terbinafine are commonly used to treat fungal infections. They induce the accumulation of reactive oxygen species (ROS) in fungi, resulting in the death of fungal cells. ROS are highly reactive molecules, such as oxygen (O2), superoxide anion (O2•-), hydrogen peroxide (H2O2) and hydroxyl radicals (•OH). Although ROS generation is useful for killing pathogenic fungi, it is cytotoxic to human keratinocytes. To the best of our knowledge, the effect of miconazole and terbinafine on HaCaT cells has not been studied with respect to intracellular ROS stimulation. We hypothesized that miconazole and terbinafine have anti-wound healing effects on skin cells when used in antifungal treatment because they generate ROS in fungal cells. We used sulforhodamine B protein staining to investigate cytotoxicity and 2',7'-dichlorofluorescein diacetate to determine ROS accumulation at the 50% inhibitory concentrations of miconazole and terbinafine in HaCaT cells. Our preliminary results showed that topical treatment with miconazole and terbinafine induced cytotoxic responses, with miconazole showing higher cytotoxicity than terbinafine. Both the treatments stimulated ROS in keratinocytes, which may induce oxidative stress and cell death. This suggests a negative correlation between intracellular ROS accumulation in keratinocytes treated with miconazole or terbinafine and the healing of fungi-infected skin wounds.

Single-Phonon Addition and Subtraction to a Mechanical Thermal State.

Adding or subtracting a single quantum of excitation to a thermal state of a bosonic system has the counter-intuitive effect of approximately doubling its mean occupation. We perform the first experimental demonstration of this effect outside optics by implementing single-phonon addition and subtraction to a thermal state of a mechanical oscillator via Brillouin optomechanics in an optical whispering-gallery microresonator. Using a detection scheme that combines single-photon counting and optical heterodyne detection, we observe this doubling of the mechanical thermal fluctuations to a high precision. The capabilities of this joint click-dyne detection scheme adds a significant new dimension for optomechanical quantum science and applications.

Non-Gaussian Mechanical Motion via Single and Multiphonon Subtraction from a Thermal State.

Quantum optical measurement techniques offer a rich avenue for quantum control of mechanical oscillators via cavity optomechanics. In particular, a powerful yet little explored combination utilizes optical measurements to perform heralded non-Gaussian mechanical state preparation followed by tomography to determine the mechanical phase-space distribution. Here, we experimentally perform heralded single-phonon and multiphonon subtraction via photon counting to a laser-cooled mechanical thermal state with a Brillouin optomechanical system at room temperature and use optical heterodyne detection to measure the s-parametrized Wigner distribution of the non-Gaussian mechanical states generated. The techniques developed here advance the state of the art for optics-based tomography of mechanical states and will be useful for a broad range of applied and fundamental studies that utilize mechanical quantum-state engineering and tomography.

Age, sex, and disease status as determinants of skin hydration and transepidermal water loss among children with and without eczema.

PURPOSE: Skin hydration (SH) and transepidermal water loss (TEWL) are important skin biophysical parameters for assessment of childhood eczema. This study investigated whether age, sex, and disease status influence these parameters. METHODS: Skin hydration and TEWL were measured by Delfin MoistureMeterSC and Delfin Vapometer SWL5, respectively, among children aged ≤18 years with and without eczema. Disease status was evaluated using Scoring Atopic Dermatitis (SCORAD) and Nottingham Eczema Severity Score (NESS) clinical tools. RESULTS: Clinical scores and objective measurements were reviewed for 132 patients with eczema and 120 patients without eczema. In both sexes, SH was significantly higher among children aged ≤2 years with and without eczema than among children aged >2 years with and without eczema. Among children aged >2 years, SH was higher among girls with and without eczema than among boys with and without eczema. Regardless of age or sex, SH was lower among children with eczema than among children without eczema. Age-, sex-, and disease-related differences were not observed for TEWL. Skin hydration was negatively correlated with objective SCORAD (r=-0.418, P<0.001), overall SCORAD (r=-0.385, P<0.001), oedema/papulation (r=-0.243, P=0.041), lichenification (r=-0.363, P=0.002), dryness (r=-0.415, P<0.001), and intensity (r=-0.266, P=0.025). Transepidermal water loss was positively correlated with objective SCORAD (r=0.209, P=0.018), overall SCORAD (r=0.215, P=0.015), and lichenification (r=0.240, P=0.043). Skin hydration was negatively correlated with TEWL among children without eczema (r=-0.401, P<0.001), but not among children with eczema. CONCLUSION: Skin hydration can be used to distinguish clinical differences in eczema based on age, sex, and disease status.

Hip fractures are preventable: a proposal for osteoporosis screening and fall prevention in older people.

Osteoporosis is highly prevalent but underdiagnosed and undertreated in Hong Kong. Fragility fractures associated with osteoporosis often result in loss of independence and increased mortality for home-dwelling patients, imposing a high socio-economic burden on society. This issue requires urgent attention given the rapid growth of the elderly population in Hong Kong by approximately 4.3% each year. To address this situation, a group of experts convened to discuss practical ways to reduce the burden of fractures and formulated three recommendations: first, all men (aged ≥70 years) and women (aged ≥65 years) should receive universal dual-energy X-ray absorptiometry assessment for osteoporosis. Second, all men (aged ≥70 years) and women (aged ≥65 years) with a fracture-risk assessment-derived 10-year risk (hip fracture with bone mineral density) ≥3% should receive ≥3 years of anti-osteoporotic treatment. Third, comprehensive structured assessment (including dual-energy X-ray absorptiometry) should be conducted in older patients with a history of falling. By implementing these recommendations, we estimate that we could prevent 5234 hip fractures in 10 years, an annual incidence reduction of approximately 7%, and save HK$425 million in direct medical costs plus substantial indirect savings. Ample clinical and cost-effectiveness data support these recommendations, and studies in Hong Kong and abroad could serve as models on how to implement them. We are confident that by applying these recommendations rigorously and systematically, a significant reduction in hip fractures in Hong Kong is achievable.

Sperm cryopreservation prior to gonadotoxic treatment: experience of a single academic centre over 4 decades.

STUDY QUESTION: What is the natural history of outcomes of sperm cryostorage at an Australian tertiary academic centre? SUMMARY ANSWER: Cryostorage is feasible in virtually all men facing gonadotoxic therapy but the timing of sperm disposal varies according to the reason for it. WHAT IS KNOWN ALREADY: Gonadotoxic treatment for cancer or non-cancer diseases damages spermatogenesis and impairs male fertility. Sperm cryopreservation is an established technique to preserve male fertility prior to gonadotoxic treatment. STUDY DESIGN, SIZE, DURATION: A retrospective review of clinical, anthropometric, semen analysis and hormonal data from 1978 to 2017 involving 2717 men comprising 2085 men with cancer, 234 non-cancer disease and 398 healthy controls, in a single tertiary academic centre with the same clinic and laboratory staff. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Sperm output was analysed according to diseases, the feasibility of sperm cryostorage notably for adolescents, regional access to an urban cryostorage facility, the determinants of sperm output and time-dependent disposal of cryostored sperm. Semen samples were assessed by contemporaneous WHO methods. MAIN RESULTS AND THE ROLE OF CHANCE: Of 2085 men with cancer, 904 (43%) had haematological malignancies, 680 (33%) testicular cancers and 136 (6.5%) were adolescents. Most men (89%) and adolescents (80%) could collect sperm. Sperm output for all cancers and non-cancer diseases was lower than controls. Sperm output correlated positively with total testicular volume (r = 0.44, P < 0.0001) and negatively with serum FSH and LH (r = -0.24, -0.12, respectively, both P < 0.0001) but not testosterone. For all stored samples, the median time in cryostorage was 8.5 years, 7% were transferred for use to induce pregnancy (median time 2.5 years) and 62.2% were discarded as no longer needed (return of fertility, 35.9% median 3.5 years; death, 26.3%, median 6.5 years), the high disposal rate reflecting regular annual follow-up to establish ongoing need for continued cryostorage. Cryostorage facilities are not available in remote and rural areas of the State and the proportion of outer regional and remote area residents cryostoring sperm was only about half that compared with urban residents. LIMITATIONS, REASONS FOR CAUTION: This study does not report the pregnancy outcomes of the patients who used the cryostored sperm, due to recent limitations on health data privacy. WIDER IMPLICATIONS OF THE FINDINGS: Sperm cryostorage is feasible for virtually all men, including sufficiently mature adolescents, who can collect semen to insure future paternity as well as making positive psychological preparation for the patient's survival. Disposal of cryostored material when no longer required is efficient with regular follow-up. Sperm cryopreservation should be an integral part of comprehensive treatment plan in men receiving gonadotoxic treatment but remains underutilized. STUDY FUNDING/COMPETING INTEREST(S): There was no external funding for this study and there were no relevant conflicts of interest.

Recent advances on topical antimicrobials for skin and soft tissue infections and their safety concerns.

Antimicrobial resistance of disease-related microorganisms is considered a worldwide prevalent and serious issue which increases the failure of treatment outcomes and leads to high mortality. Considering that the increased resistance to systemic antimicrobial therapy often needs of the use of more toxic agents, topical antimicrobial therapy emerges as an attractive route for the treatment of infectious diseases. The topical antimicrobial therapy is based on the absorption of high drug doses in a readily accessible skin surface, resulting in a reduction of microbial proliferation at infected skin sites. Topical antimicrobials retain the following features: (a) they are able to escape the enzymatic degradation and rapid clearance in the gastrointestinal tract or the first-pass metabolism during oral administration; (b) alleviate the physical discomfort related to intravenous injection; (c) reduce possible adverse effects and drug interactions of systemic administrations; (d) increase patient compliance and convenience; and (e) reduce the treatment costs. Novel antimicrobials for topical application have been widely exploited to control the emergence of drug-resistant microorganisms. This review provides a description of antimicrobial resistance, common microorganisms causing skin and soft tissue infections, topical delivery route of antimicrobials, safety concerns of topical antimicrobials, recent advances, challenges and future prospective in topical antimicrobial development.

Impact of germline and somatic missense variations on drug binding sites.

Advancements in next-generation sequencing (NGS) technologies are generating a vast amount of data. This exacerbates the current challenge of translating NGS data into actionable clinical interpretations. We have comprehensively combined germline and somatic nonsynonymous single-nucleotide variations (nsSNVs) that affect drug binding sites in order to investigate their prevalence. The integrated data thus generated in conjunction with exome or whole-genome sequencing can be used to identify patients who may not respond to a specific drug because of alterations in drug binding efficacy due to nsSNVs in the target protein's gene. To identify the nsSNVs that may affect drug binding, protein-drug complex structures were retrieved from Protein Data Bank (PDB) followed by identification of amino acids in the protein-drug binding sites using an occluded surface method. Then, the germline and somatic mutations were mapped to these amino acids to identify which of these alter protein-drug binding sites. Using this method we identified 12 993 amino acid-drug binding sites across 253 unique proteins bound to 235 unique drugs. The integration of amino acid-drug binding sites data with both germline and somatic nsSNVs data sets revealed 3133 nsSNVs affecting amino acid-drug binding sites. In addition, a comprehensive drug target discovery was conducted based on protein structure similarity and conservation of amino acid-drug binding sites. Using this method, 81 paralogs were identified that could serve as alternative drug targets. In addition, non-human mammalian proteins bound to drugs were used to identify 142 homologs in humans that can potentially bind to drugs. In the current protein-drug pairs that contain somatic mutations within their binding site, we identified 85 proteins with significant differential gene expression changes associated with specific cancer types. Information on protein-drug binding predicted drug target proteins and prevalence of both somatic and germline nsSNVs that disrupt these binding sites can provide valuable knowledge for personalized medicine treatment. A web portal is available where nsSNVs from individual patient can be checked by scanning against DrugVar to determine whether any of the SNVs affect the binding of any drug in the database.

Preclinical in vivo and in vitro comparison of the translocator protein PET ligands [18F]PBR102 and [18F]PBR111.

PURPOSE: To determine the metabolic profiles of the translocator protein ligands PBR102 and PBR111 in rat and human microsomes and compare their in vivo binding and metabolite uptake in the brain of non-human primates (Papio hamadryas) using PET-CT. METHODS: In vitro metabolic profiles of PBR102 and PBR111 in rat and human liver microsomes were assessed by liquid chromatography-tandem mass spectrometry. [18F]PBR102 and [18F]PBR111 were prepared by nucleophilic substitution of their corresponding p-toluenesulfonyl precursors with [18F]fluoride. List mode PET-CT brain imaging with arterial blood sampling was performed in non-human primates. Blood plasma measurements and metabolite analysis, using solid-phase extraction, provided the metabolite profile and metabolite-corrected input functions for kinetic model fitting. Blocking and displacement PET-CT scans, using PK11195, were performed. RESULTS: Microsomal analyses identified the O-de-alkylated, hydroxylated and N-de-ethyl derivatives of PBR102 and PBR111 as the main metabolites. The O-de-alkylated compounds were the major metabolites in both species; human liver microsomes were less active than those from rat. Metabolic profiles in vivo in non-human primates and previously published rat experiments were consistent with the microsomal results. PET-CT studies showed that K1 was similar for baseline and blocking studies for both radiotracers; VT was reduced during the blocking study, suggesting low non-specific binding and lack of appreciable metabolite uptake in the brain. CONCLUSIONS: [18F]PBR102 and [18F]PBR111 have distinct metabolic profiles in rat and non-human primates. Radiometabolites contributed to non-specific binding and confounded in vivo brain analysis of [18F]PBR102 in rodents; the impact in primates was less pronounced. Both [18F]PBR102 and [18F]PBR111 are suitable for PET imaging of TSPO in vivo. In vitro metabolite studies can be used to predict in vivo radioligand metabolism and can assist in the design and development of better radioligands.

Squeezed light from a diamond-turned monolithic cavity.

For some crystalline materials, a regime can be found where continuous ductile cutting is feasible. Using precision diamond turning, such materials can be cut into complex optical components with high surface quality and form accuracy. In this work we use diamond-turning to machine a monolithic, square-shaped, doubly-resonant LiNbO3 cavity with two flat and two convex facets. When additional mild polishing is implemented, the Q-factor of the resonator is found to be limited only by the material absorption loss. We show how our monolithic square resonator may be operated as an optical parametric oscillator that is evanescently coupled to free-space beams via birefringent prisms. The prism arrangement allows for independent and large tuning of the fundamental and second harmonic coupling rates. We measure 2.6 ± 0.5 dB of vacuum squeezing at 1064 nm using our system. Potential improvements to obtain higher degrees of squeezing are discussed.

Concurrent beneficial (vitamin D production) and hazardous (cutaneous DNA damage) impact of repeated low-level summer sunlight exposures.

BACKGROUND: The concurrent impact of repeated low-level summer sunlight exposures on vitamin D production and cutaneous DNA damage, potentially leading to mutagenesis and skin cancer, is unknown. OBJECTIVES: This is an experimental study (i) to determine the dual impact of repeated low-level sunlight exposures on vitamin D status and DNA damage/repair (via both skin and urinary biomarkers) in light-skinned adults; and (ii) to compare outcomes following the same exposures in brown-skinned adults. METHODS: Ten white (phototype II) and six South Asian volunteers (phototype V), aged 23-59 years, received 6 weeks' simulated summer sunlight exposures (95% ultraviolet A/5% ultraviolet B, 1·3 standard erythemal doses three times weekly) wearing summer clothing exposing ~35% body surface area. Assessments made were circulating 25-hydroxyvitamin D [25(OH)D], immunohistochemistry for cyclobutane pyrimidine dimer (CPD)-positive nuclei and urinary biomarkers of direct and oxidative (8-oxo-deoxyguanosine) DNA damage. RESULTS: Serum 25(OH)D rose from mean 36·5 ± 13·0 to 54·3 ± 10·5 nmol L-1 (14·6 ± 5·2 to 21·7 ± 4·2 ng mL-1 ) in phototype II vs. 17·2 ± 6·3 to 25·5 ± 9·5 nmol L-1 (6·9 ± 2·5 to 10·2 ± 3·8 ng mL-1 ) in phototype V (P < 0·05). Phototype II skin showed CPD-positive nuclei immediately postcourse, mean 44% (range 27-84) cleared after 24 h, contrasting with minimal DNA damage and full clearance in phototype V (P < 0·001). The findings did not differ from those following single ultraviolet radiation (UVR) exposure. Urinary CPDs remained below the detection threshold in both groups; 8-oxo-deoxyguanosine was higher in phototype II than V (P = 0·002), but was unaffected by UVR. CONCLUSIONS: Low-dose summer sunlight exposures confer vitamin D sufficiency in light-skinned people concurrently with low-level, nonaccumulating DNA damage. The same exposures produce minimal DNA damage but less vitamin D in brown-skinned people. This informs tailoring of sun-exposure policies.

Uncoiling collagen: a multidimensional mass spectrometry study.

Mass spectrometry can be used to determine structural information about ions by activating precursors and analysing the resulting series of fragments. Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry (2D FT-ICR MS) is a technique that correlates the mass-to-charge (m/z) ratio of fragment and precursor ions in a single spectrum. 2D FT-ICR MS records the fragmentation of all ions in a sample without the need for isolation. To analyse specific precursors, horizontal cross-sections of the spectrum (fragment ion scans) are taken, providing an alternative to conventional tandem mass spectrometry (MS/MS) experiments. In this work, 2D FT-ICR MS has been used to study the tryptic digest of type I collagen, a large protein. Fragment ion scans have been extracted from the 2D FT-ICR MS spectrum for precursor m/z ratios: 951.81, 850.41, 634.34, and 659.34, and 2D FT-ICR MS spectra are compared with a set of 1D MS/MS spectra using different fragmentation methods. The results show that two-dimensional mass spectrometry excells at MS/MS of complex mixtures, simplifying spectra by eliminating contaminant peaks, and aiding the identification of species in the sample. Currently, with desktop computers, 2D FT-ICR MS is limited by data processing power, a limitation which should be alleviated using cluster parallel computing. In order to explore 2D FT-ICR MS for collagen, with reasonable computing time, the resolution in the fragment ion dimension is limited to 256k data points (compared to 4M data points in 1D MS/MS spectra), but the vertical precursor ion dimension has 4096 lines, so the total data set is 1G data points (4 Gbytes). The fragment ion coverage obtained with a blind, unoptimized 2D FT-ICR MS experiment was lower than conventional MS/MS, but MS/MS information is obtained for all ions in the sample regardless of selection and isolation. Finally, although all 2D FT-ICR MS peak assignments were made with the aid of 1D FT-ICR MS data, these results demonstrate the promise of 2D FT-ICR MS as a technique for studying complex protein digest mixtures.

How well can we quantify dust deposition to the ocean?

Deposition of continental mineral aerosols (dust) in the Eastern Tropical North Atlantic Ocean, between the coast of Africa and the Mid-Atlantic Ridge, was estimated using several strategies based on the measurement of aerosols, trace metals dissolved in seawater, particulate material filtered from the water column, particles collected by sediment traps and sediments. Most of the data used in this synthesis involve samples collected during US GEOTRACES expeditions in 2010 and 2011, although some results from the literature are also used. Dust deposition generated by a global model serves as a reference against which the results from each observational strategy are compared. Observation-based dust fluxes disagree with one another by as much as two orders of magnitude, although most of the methods produce results that are consistent with the reference model to within a factor of 5. The large range of estimates indicates that further work is needed to reduce uncertainties associated with each method before it can be applied routinely to map dust deposition to the ocean. Calculated dust deposition using observational strategies thought to have the smallest uncertainties is lower than the reference model by a factor of 2-5, suggesting that the model may overestimate dust deposition in our study area.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

Topical Therapy with Mesenchymal Stem Cells Following an Acute Experimental Head Injury Has Benefits in Motor-Behavioral Tests for Rodents.

BACKGROUND: The neuroprotective effects of mesenchymal stem cells (MSCs) have been reported in rodent and in preliminary clinical studies. MSCs are usually transplanted to patients by systemic infusion. However, only a few of the infused MSCs are delivered to the brain because of pulmonary trapping and the blood-brain barrier. In this study, MSCs were topically applied to the site of traumatic brain injury (TBI) and the neuroprotective effects were assessed. MATERIALS AND METHODS: TBI was induced in Sprague-Dawley (SD) rats with an electromagnetically controlled cortical impact device after craniotomy was performed between the bregma and lambda, 1 mm lateral to the midline. We applied 1.5 million MSCs, derived from the adipose tissue of transgenic green fluorescent protein (GFP)-SD rats, to the exposed cerebral cortex at the injured site. The MSCs were held in position by a thin layer of fibrin. Neurological function in the test (n = 10) and control (n = 10) animals was evaluated using the rotarod test, the water maze test, and gait analysis at different time points. RESULTS: Within 5 days following topical application, GFP-positive cells were found in the brain parenchyma. These cells co-expressed with markers of Glial fibrillary acidic protein (GFAP), nestin, and NeuN. There was less neuronal death in CA1 and CA3 of the hippocampus in the test animals. Neurological functional recovery was significantly improved. CONCLUSION: Topically applied MSCs can migrate to the injured brain parenchyma and offer neuroprotective effects.