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1.
Nature ; 612(7940): 528-533, 2022 12.
Article in English | MEDLINE | ID: mdl-36477538

ABSTRACT

Sexual reproduction and meiotic sex are deeply rooted in the eukaryotic tree of life, but mechanisms determining sex or mating types are extremely varied and are only well characterized in a few model organisms1. In malaria parasites, sexual reproduction coincides with transmission to the vector host. Sex determination is non-genetic, with each haploid parasite capable of producing either a male or a female gametocyte in the human host2. The hierarchy of events and molecular mechanisms that trigger sex determination and maintenance of sexual identity are yet to be elucidated. Here we show that the male development 1 (md1) gene is both necessary and sufficient for male fate determination in the human malaria parasite Plasmodium falciparum. We show that Md1 has a dual function stemming from two separate domains: in sex determination through its N terminus and in male development from its conserved C-terminal LOTUS/OST-HTH domain. We further identify a bistable switch at the md1 locus, which is coupled with sex determination and ensures that the male-determining gene is not expressed in the female lineage. We describe one of only a few known non-genetic mechanisms of sex determination in a eukaryote and highlight Md1 as a potential target for interventions that block malaria transmission.


Subject(s)
Gene Expression Regulation , Malaria, Falciparum , Malaria , Parasites , Sex Determination Processes , Transcription, Genetic , Animals , Humans , Malaria/parasitology , Malaria, Falciparum/parasitology , Parasites/genetics , Plasmodium falciparum/genetics , Reproduction , Male , Female , Sex Determination Processes/genetics , Sex Characteristics
2.
Phys Rev Lett ; 129(12): 127601, 2022 Sep 16.
Article in English | MEDLINE | ID: mdl-36179158

ABSTRACT

We use an x-ray free-electron laser to study the lattice dynamics following photoexcitation with ultrafast near-UV light (wavelength 266 nm, 50 fs pulse duration) of the incipient ferroelectric potassium tantalate, KTaO_{3}. By probing the lattice dynamics corresponding to multiple Brillouin zones through the x-ray diffuse scattering with pulses from the Linac Coherent Light Source (LCLS) (wavelength 1.3 Å and <10 fs pulse duration), we observe changes in the diffuse intensity associated with a hardening of the transverse acoustic phonon branches along Γ to X and Γ to M. Using force constants from density functional theory, we fit the quasiequilibrium intensity and obtain the instantaneous lattice temperature and density of photoexcited charge carriers. The density functional theory calculations demonstrate that photoexcitation transfers charge from oxygen 2p derived π-bonding orbitals to Ta 5d derived antibonding orbitals, further suppressing the ferroelectric instability and increasing the stability of the cubic, paraelectric structure.

3.
Nat Commun ; 13(1): 4473, 2022 Aug 02.
Article in English | MEDLINE | ID: mdl-35918314

ABSTRACT

The discovery of two-dimensional systems hosting intrinsic magnetic order represents a seminal addition to the rich landscape of van der Waals materials. CrI3 is an archetypal example, where the interdependence of structure and magnetism, along with strong light-matter interactions, provides a new platform to explore the optical control of magnetic and vibrational degrees of freedom at the nanoscale. However, the nature of magneto-structural coupling on its intrinsic ultrafast timescale remains a crucial open question. Here, we probe magnetic and vibrational dynamics in bulk CrI3 using ultrafast optical spectroscopy, revealing spin-flip scattering-driven demagnetization and strong transient exchange-mediated interactions between lattice vibrations and spin oscillations. The latter yields a coherent spin-coupled phonon mode that is highly sensitive to the driving pulse's helicity in the magnetically ordered phase. Our results elucidate the nature of ultrafast spin-lattice coupling in CrI3 and highlight its potential for applications requiring high-speed control of magnetism at the nanoscale.

4.
Nat Mater ; 21(1): 62-66, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34750539

ABSTRACT

Symmetry plays a central role in conventional and topological phases of matter, making the ability to optically drive symmetry changes a critical step in developing future technologies that rely on such control. Topological materials, like topological semimetals, are particularly sensitive to a breaking or restoring of time-reversal and crystalline symmetries, which affect both bulk and surface electronic states. While previous studies have focused on controlling symmetry via coupling to the crystal lattice, we demonstrate here an all-electronic mechanism based on photocurrent generation. Using second harmonic generation spectroscopy as a sensitive probe of symmetry changes, we observe an ultrafast breaking of time-reversal and spatial symmetries following femtosecond optical excitation in the prototypical type-I Weyl semimetal TaAs. Our results show that optically driven photocurrents can be tailored to explicitly break electronic symmetry in a generic fashion, opening up the possibility of driving phase transitions between symmetry-protected states on ultrafast timescales.

5.
Sci Rep ; 11(1): 20623, 2021 10 18.
Article in English | MEDLINE | ID: mdl-34663838

ABSTRACT

Due to insufficient ventilation, public toilets present high risks for cross-infection. The study investigated 61 public toilets to identify the causes and locations of biological contaminated sources. Airborne and surface bacterial contamination, carbon dioxide concentration, and surface ammonia levels were measured. Both bacterial contamination and CO2 are higher in non-ventilated toilets compared to their ventilated counterparts. Bacteria colony forming units (CFUs) in a public toilet with poor ventilation can reach 5 times the number of CFUs outside of the toilet. This suggests that non-ventilated public toilets present a higher risk of cross-infection. Areas near all kinds of sanitary equipment (toilet bowls, squat toilets and urinals) were highly contaminated, indicating that enhanced cleaning regimes are necessary. Further, lidless trash bins present a higher risk as contaminated matter within the trash bins is not inhibited from being released into the environment. Ventilation and cleaning need to be improved to mitigate the risk of cross-infection in public toilets.

6.
J Nutr Health Aging ; 25(1): 134-140, 2021.
Article in English | MEDLINE | ID: mdl-33367474

ABSTRACT

OBJECTIVES: The study aimed to develop a brief geriatric assessment (BGA) tool for the general practitioner to evaluate geriatric syndromes in community-dwelling older adults. DESIGN: A cross-sectional study. SETTING: 58 communities from four aging cities in Taiwan. PARTICIPANTS: 1,258 community-dwelling older adults aged 65 years and above. MEASUREMENTS: The BGA targeted physical function impairment, cognitive impairment, and mood impairment. The cutoff values of physical function tests (handgrip strength and 6-meter walk test [6MWT]) were estimated by receiver operating characteristic analysis. Second, the diagnostic validity of the BGA was calculated in terms of sensitivity, specificity, and predictive values, which were compared to corresponding comprehensive geriatric assessment (CGA) items. Third, the associated risk factors of geriatric syndromes were selected using stepwise logistic regression. Finally, we combined items selected from literature and CGA and then proposed a practical BGA framework. RESULTS: The proposed BGA comprised dominant handgrip strength, 6MWT, self-report personal birthday, address, and telephone number, question 'Do you have depressive mood for the past two weeks?', Rinne tuning-fork tests, Snellen scale, and body mass index. It evaluated multidimensional aspects of geriatrics syndromes including physical, cognitive, mood, and sensory impairment, sarcopenia, and nutrition status. Sensitivities in the Taiwan BGA items ranged from 48% for dominant handgrip strength to 97.6% for 6MWT corresponding to physical impairment; 58.3% for cognitive impairment corresponding to Short Portable Mental Status Questionnaire; 62.7% for mood impairment corresponding to Geriatric Depression Scale. The Taiwan BGA for the general practitioner takes less than 10 minutes and is suitable in the community setting. CONCLUSION: Early management of geriatric syndromes in the community is important. The current study demonstrated a practical BGA tool for the general practitioner to comprehensively assess geriatric syndromes in community-dwelling older adults.


Subject(s)
General Practitioners/standards , Geriatric Assessment/methods , Independent Living/standards , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male
7.
Eur J Pediatr ; 180(1): 99-107, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32556509

ABSTRACT

Pain management is an important issue which impacts the prognosis of neonates in neonatal intensive care units. Evidence has shown that professionals' knowledge and attitudes regarding pain management can impact the quality of their practice. The purpose of this study was to evaluate the knowledge, attitudes, and practices of neonatal professionals regarding neonatal pain management. A cross-sectional study was performed involving neonatal physicians and nurses, using a research questionnaire to investigate the knowledge and attitudes of professionals as well as to assess their practice of pain management. Research found an apparent discrepancy between the knowledge levels of neonatologists and nurses regarding pain assessment and management, with nurses displaying weaker professional knowledge and more negative attitudes toward pain management than did neonatologists. Additionally, research revealed a lack of knowledge and negative attitudes among participants regarding the provision of sufficient opioid analgesics to sick infants during invasive procedures and even for dying neonates. There is an urgent need for continuing education regarding neonatal pain management with the goal of empowering neonatal professionals; further research is needed into the question of how to translate education into more reliable practice.Conclusion: This research provides useful information regarding the knowledge, attitudes, and clinical practice of neonatal pain management among neonatologists and nurses and points out some differences in the knowledge levels of these two groups. What is Known: •Neonates can perceive and respond to pain stimuli by showing their biological signals similarly to children and adults. •Untreated or insufficient pain management for high-risk neonates has short-term. negative effects and may also induce long-term negative effects. What is New: •The level of knowledge, the attitudes, and the practices regarding neonatal pain in intensive care are different among neonatal professionals. •There is an urgent need to provide interdisciplinary continuing education to improve the knowledge of neonatal professionals and encourage them to more highly prioritize neonatal pain management.


Subject(s)
Health Knowledge, Attitudes, Practice , Pain Management , Adult , Attitude of Health Personnel , Child , Cross-Sectional Studies , Humans , Infant, Newborn , Intensive Care Units, Neonatal , Neonatologists , Surveys and Questionnaires
9.
Sci Data ; 6(1): 289, 2019 11 26.
Article in English | MEDLINE | ID: mdl-31772199

ABSTRACT

Thermal discomfort is one of the main triggers for occupants' interactions with components of the built environment such as adjustments of thermostats and/or opening windows and strongly related to the energy use in buildings. Understanding causes for thermal (dis-)comfort is crucial for design and operation of any type of building. The assessment of human thermal perception through rating scales, for example in post-occupancy studies, has been applied for several decades; however, long-existing assumptions related to these rating scales had been questioned by several researchers. The aim of this study was to gain deeper knowledge on contextual influences on the interpretation of thermal perception scales and their verbal anchors by survey participants. A questionnaire was designed and consequently applied in 21 language versions. These surveys were conducted in 57 cities in 30 countries resulting in a dataset containing responses from 8225 participants. The database offers potential for further analysis in the areas of building design and operation, psycho-physical relationships between human perception and the built environment, and linguistic analyses.


Subject(s)
Built Environment , Thermosensing , Humans , Surveys and Questionnaires , Temperature
10.
J Nutr Health Aging ; 23(9): 849-855, 2019.
Article in English | MEDLINE | ID: mdl-31641735

ABSTRACT

OBJECTIVES: Few studies have focused on weight change and frailty, especially in Asia. This research aimed to evaluate midlife body mass index (BMI) trajectory and assess its relationship with frailty 8 years later in Taiwan. DESIGN: A prospective cohort study. SETTING AND PARTICIPANTS: Data were retrieved from the Taiwan Longitudinal Study on Aging conducted from 1999 to 2007. The analysis was restricted to respondents aged between 50 to 69 years old, who were not frail in 1999 and were alive in 2007 (n=1609). MEASUREMENTS: Frailty was defined using the Fried criteria. The group-based model of trajectory was used to estimate BMI trajectories among elderly participants. Logistic regression analysis was used to examine the association between BMI change and frailty. RESULTS: Four trajectory classes were identified and each remained stable during the 8-year follow-up. There were 316 participants (20.3%) in the low-normal weight group (baseline BMI=20.38 kg/m2), 737 participants (44.7%) in the high-normal weight group (baseline BMI=23.22 kg/m2), 449 participants (28.4%) in the overweight group (baseline BMI=26.24 kg/m2), and 107 participants (6.6%) in the obesity group (baseline BMI=30.65 kg/m2). After adjustment for confounding factors, the low-normal weight group and obesity group were associated with increased frailty compared with the high-normal weight group. CONCLUSION: Our results showed that the BMI trajectories of midlife individuals tended to be constant and those in both the low-normal weight group and obesity group had an increased risk of developing frailty in later life. Therefore, an optimal weight-targeting strategy should be considered for Asian elderly individuals.


Subject(s)
Aging/physiology , Body Mass Index , Frailty/physiopathology , Aged , Asia , Female , Humans , Longitudinal Studies , Male , Middle Aged , Obesity/physiopathology , Prospective Studies , Risk Factors , Taiwan , Thinness/physiopathology
11.
Osteoarthritis Cartilage ; 27(12): 1755-1760, 2019 12.
Article in English | MEDLINE | ID: mdl-31400498

ABSTRACT

PURPOSE: Knee osteoarthritis (KOA) is characterized by pain and decreased gait function. This study assessed key features that can be used as mechanical biomarkers for KOA severity and progression. The identified features were validated statistically and were further examined by developing a classification model based on a machine-learning algorithm. METHODS: The study included 227 volunteers with various grades of KOA. The severity of KOA was graded using the Kellgren-Lawrence (KL) system. A total of 165 features were extracted from the gait data. The key features were selected using neighborhood component analysis. The selected features were validated using the t-test. Then, the features were examined by building a classification model using a random forest algorithm. RESULTS: Twenty features were identified that could discriminate the grade of KOA, including nine features extracted from the knee joint, seven from the hip, two from the ankle and two from the spatiotemporal gait parameters. The t-test showed that some features differed significantly between health and sever group, while some were significantly different among the severe group, and others were significantly different for all KL grades. The areas under the receiver operating characteristic curves for classification were 0.974, 0.992, 0.845, 0.894, and 0.905 for KL grades 0 through 4, respectively. CONCLUSION: Key gait features reflecting the grade of KOA were identified. The results of the statistical analysis and machine-learning algorithm show that the features can discriminate the severity of disease according to the KL grade.


Subject(s)
Gait Analysis , Machine Learning , Osteoarthritis, Knee/diagnostic imaging , Osteoarthritis, Knee/physiopathology , Adult , Aged , Female , Gait/physiology , Humans , Male , Middle Aged , Radiography , Severity of Illness Index
12.
Int J Prison Health ; 15(3): 273-281, 2019 08 29.
Article in English | MEDLINE | ID: mdl-31329036

ABSTRACT

PURPOSE: Incarceration provides an opportunity for screening and treatment of sexually transmitted and blood-borne infections (STBBIs) in high-risk groups. The purpose of this paper is to determine positivity rates of STBBI screening within correctional facilities using opt-in strategies and estimate the proportion of admissions tested. DESIGN/METHODOLOGY/APPROACH: A cross-sectional, retrospective review of testing data from January 2012 to August 2015 from three provincial correctional facilities located in Alberta, Canada was completed. Analysis variables included STBBI, gender, facility, collection year and age. STBBI-stratified analysis was performed to identify correlates for positivity using univariate and logistic regressions. FINDINGS: Overall prevalence of chlamydia was 11.2 percent and gonorrhea was 3.5 percent; correlates for both were younger age and facility type. The syphilis prevalence rate was 3.2 percent; correlates included being female, older age, adult facilities, with later years being protective. In total, 14 (0.3 percent) newly diagnosed HIV cases were found, prevalence increased with age. HBV prevalence was 1.7 percent with no significant correlations. Nearly one-tenth (n=422) of those screened for HCV antibody were positive; all variables were significantly correlated. Overall estimates of the proportion of admissions tested by STBBI were low and ranged from 4.8 to 16.1 percent. ORIGINALITY/VALUE: This study found high rates of STBBI in correctional facilities and showed that only a small proportion of the population was tested using an opt-in strategy. Shifting to an "opt-out" strategy may be warranted.


Subject(s)
Mass Screening/organization & administration , Prisons/organization & administration , Sexually Transmitted Diseases/diagnosis , Sexually Transmitted Diseases/epidemiology , Adolescent , Adult , Age Factors , Blood-Borne Pathogens , Canada/epidemiology , Cross-Sectional Studies , Female , HIV Infections/diagnosis , HIV Infections/epidemiology , Hepatitis/diagnosis , Hepatitis/epidemiology , Humans , Male , Middle Aged , Public Health , Retrospective Studies , Sex Factors , Young Adult
13.
Med Vet Entomol ; 33(2): 220-227, 2019 06.
Article in English | MEDLINE | ID: mdl-30628101

ABSTRACT

The microbial larvicides Bacillus thuringiensis var. israelensis (Bti) and Bacillus sphaericus (Bs) (Bacillales: Bacillaceae) are well known for their efficacy and safety in mosquito control. In order to assess their potential value in future mosquito control strategies in western Kenya, the current study tested the susceptibility of five populations of Anopheles gambiae complex mosquitoes (Diptera: Culicidae), collected from five diverse ecological sites in this area, to Bti and Bs under laboratory conditions. In each population, bioassays were conducted with eight concentrations of larvicide (Bti/Bs) in four replicates and were repeated on three separate days. Larval mortality was recorded at 24 h or 48 h after the application of larvicide and subjected to probit analysis. A total of 2400 An. gambiae complex larvae from each population were tested for their susceptibility to Bti and Bs. The mean (± standard error of the mean, SEM) lethal concentration values of Bti required to achieve 50% and 95% larval mortality (LC50 and LC95 ) across the five populations were 0.062 (± 0.005) mg/L and 0.797 (± 0.087) mg/L, respectively. Corresponding mean (± SEM) values for Bs were 0.058 (± 0.005) mg/L and 0.451 (± 0.053) mg/L, respectively. Statistical analysis indicated that the five populations of An. gambiae complex mosquitoes tested were fully susceptible to Bti and Bs, and there was no significant variation in susceptibility among the tested populations.


Subject(s)
Anopheles , Bacillaceae/chemistry , Bacillus thuringiensis/chemistry , Insecticides , Mosquito Control , Pest Control, Biological , Animals , Anopheles/growth & development , Kenya , Larva/growth & development
14.
Transplant Proc ; 50(8): 2496-2501, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30316385

ABSTRACT

BACKGROUND: Low levels of natriuretic peptide may activate the renin-angiotensin-aldosterone system, which may contribute to the development of obesity. Therefore, in study we aim to evaluate the relationship between metabolic syndrome (MetS) and serum N-terminal pro‒B-type natriuretic peptide (NT-proBNP) concentration in kidney transplant recipients. METHODS: Fasting blood samples were obtained from 66 kidney transplant recipients. MetS and its components were defined using the diagnostic criteria of the International Diabetes Federation. RESULTS: A total of 20 patients (30.3%) had MetS. Hypertension, prevalence of diabetes, use of statin or fibrate, body weight, body mass index, waist circumference, body fat mass, and levels of systolic blood pressure, total cholesterol, triglyceride, blood urea nitrogen, insulin, and HOMA-IR were higher, whereas the levels of high-density lipoprotein cholesterol and NT-proBNP were lower in patients with MetS. Logarithmically transformed creatinine and log-HOMA-IR were associated with NT-proBNP levels in a multivariable linear regression analysis. Multivariate logistic regression analysis revealed that NT-proBNP was an independent predictor of MetS in kidney transplant recipients. CONCLUSION: Our study has revealed that fasting level of NT-proBNP was negatively associated with MetS and that serum creatinine and HOMA-IR were independent predictors of serum NT-proBNP level in kidney transplant recipients.


Subject(s)
Kidney Transplantation , Metabolic Syndrome/blood , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Adult , Aged , Body Mass Index , Creatinine/blood , Female , Humans , Male , Metabolic Syndrome/epidemiology , Middle Aged , Prevalence , Waist Circumference
15.
Oncogene ; 37(8): 1107-1118, 2018 02 22.
Article in English | MEDLINE | ID: mdl-29155422

ABSTRACT

High-grade gliomas (HGGs) include the most common and the most aggressive primary brain tumor of adults and children. Despite multimodality treatment, most high-grade gliomas eventually recur and are ultimately incurable. Several studies suggest that the initiation, progression, and recurrence of gliomas are driven, at least partly, by cancer stem-like cells. A defining characteristic of these cancer stem-like cells is their capacity to self-renew. We have identified a hypoxia-induced pathway that utilizes the Hypoxia Inducible Factor 1α (HIF-1α) transcription factor and the JAK1/2-STAT3 (Janus Kinase 1/2 - Signal Transducer and Activator of Transcription 3) axis to enhance the self-renewal of glioma stem-like cells. Hypoxia is a commonly found pathologic feature of HGGs. Under hypoxic conditions, HIF-1α levels are greatly increased in glioma stem-like cells. Increased HIF-1α activates the JAK1/2-STAT3 axis and enhances tumor stem-like cell self-renewal. Our data further demonstrate the importance of Vascular Endothelial Growth Factor (VEGF) secretion for this pathway of hypoxia-mediated self-renewal. Brefeldin A and EHT-1864, agents that significantly inhibit VEGF secretion, decreased stem cell self-renewal, inhibited tumor growth, and increased the survival of mice allografted with S100ß-v-erbB/p53-/- glioma stem-like cells. These agents also inhibit the expression of a hypoxia gene expression signature that is associated with decreased survival of HGG patients. These findings suggest that targeting the secretion of extracellular, autocrine/paracrine mediators of glioma stem-like cell self-renewal could potentially contribute to the treatment of HGGs.


Subject(s)
Biomarkers, Tumor/metabolism , Brain Neoplasms/pathology , Glioma/pathology , Hypoxia/physiopathology , Neoplastic Stem Cells/pathology , STAT3 Transcription Factor/metabolism , Animals , Apoptosis , Biomarkers, Tumor/genetics , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Cell Proliferation , Female , Glioma/genetics , Glioma/metabolism , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Janus Kinase 1/genetics , Janus Kinase 1/metabolism , Janus Kinase 2/genetics , Janus Kinase 2/metabolism , Mice , Neoplastic Stem Cells/metabolism , Neovascularization, Pathologic , STAT3 Transcription Factor/genetics , Tumor Cells, Cultured
16.
Oncogene ; 36(38): 5439, 2017 09 21.
Article in English | MEDLINE | ID: mdl-28714963

ABSTRACT

This corrects the article DOI: 10.1038/onc.2014.184.

17.
Am J Hum Biol ; 28(6): 918-926, 2016 11.
Article in English | MEDLINE | ID: mdl-27416964

ABSTRACT

Body composition may be a better predictor of chronic disease risk than body mass index (BMI) in older populations. OBJECTIVES: We sought to validate spine fat fraction (%) from dual energy X-ray absorptiometry (DXA) spine scans as a proxy for total abdominal fat. METHODS: Total body DXA scan abdominal fat regions of interest (ROI) that have been previously validated by magnetic resonance imaging were assessed among healthy, postmenopausal women who also had antero-posterior spine scans (n = 103). ROIs were (1) lumbar vertebrae L2-L4 and (2) L2-Iliac Crest (L2-IC), manually selected by two independent raters, and (3) trunk, auto-selected by DXA software. Intra-class correlation coefficients evaluated intra and inter-rater reliability on a random subset (N = 25). Linear regression models, validated by bootstrapping, assessed the relationship between spine fat fraction (%) and total abdominal fat (%) ROIs. RESULTS: Mean age, BMI, and total body fat were 66.1 ± 4.8 y, 25.8 ± 3.8 kg/m2 and 40.0 ± 6.6%, respectively. There were no significant differences within or between raters. Linear regression models adjusted for several participant and scan characteristics were equivalent to using only BMI and spine fat fraction. The model predicted L2-L4 (Adj. R2 : 0.83) and L2-IC (Adj. R2 : 0.84) abdominal fat (%) well; the adjusted R2 for trunk fat (%) was 0.78. Model validation demonstrated minimal over-fitting (Adj. R2 : 0.82, 0.83, and 0.77 for L2-L4, L2-IC, and trunk fat, respectively). CONCLUSIONS: The strong correlation between spine fat fraction and DXA abdominal fat measures make it suitable for further development in postmenopausal chronic disease risk prediction models. Am. J. Hum. Biol. 28:918-926, 2016. © 2016Wiley Periodicals, Inc.


Subject(s)
Abdominal Fat/diagnostic imaging , Absorptiometry, Photon/methods , Postmenopause , Aged , Arizona , Body Mass Index , Female , Humans , Middle Aged , Reproducibility of Results
19.
Transplant Proc ; 48(3): 864-9, 2016 Apr.
Article in English | MEDLINE | ID: mdl-27234754

ABSTRACT

BACKGROUND: Osteoprotegerin (OPG) has pleiotropic effects on bone metabolism as well as endocrine function. Our aim was to evaluate the relationship between bone mineral density (BMD) and serum OPG concentration in renal transplant recipients. METHODS: Fasting blood samples were obtained from 69 renal transplant recipients. BMD was measured in lumbar vertebrae (L2-L4) by dual-energy X-ray absorptiometry. Eight patients (11.6%) had BMD values indicative of osteoporosis, 28 patients (40.6%) had BMD values indicative of osteopenia, and 33 patients had normal BMD values. Increased serum OPG levels (P < .001), decreased body mass index (BMI) (P = .033), and decreased body weight (P = .010) were significantly correlated with low lumbar T-score cut-off points between groups (normal, osteopenia, and osteoporosis). RESULTS: Women had significantly lower lumbar BMD values than men (P = .013). Menopause (P = .005), use of tacrolimus (P = .020), and use of cyclosporine (P = .046) were associated with lower lumbar BMD in renal transplant recipients. Univariate linear regression analysis revealed that lumbar BMD was positively correlated with height (P = .016), body weight (P = .001), and BMI (P = .015) and negatively correlated with age (P = .039) and log-OPG (P = .001). Multivariate linear regression analysis revealed that log-OPG (ß: -0.275, R(2) change = 0.154, P = .014), body weight (ß: 0.334, R(2) change = 0.073, P = .004), and age (ß: -0.285, R(2) change = 0.079, P = .008) were independent predictors of lumbar BMD values in renal transplant recipients. CONCLUSIONS: Serum OPG concentration correlated negatively with lumbar BMD values in renal transplant recipients.


Subject(s)
Bone Density , Kidney Transplantation/adverse effects , Osteoporosis/blood , Osteoprotegerin/blood , Transplant Recipients , Absorptiometry, Photon , Adult , Aged , Body Weight , Female , Humans , Lumbar Vertebrae/diagnostic imaging , Male , Middle Aged , Osteoporosis/etiology
20.
J Neurophysiol ; 116(2): 286-95, 2016 08 01.
Article in English | MEDLINE | ID: mdl-27098022

ABSTRACT

Central sensitization (CS), the increased sensitivity of the central nervous system to somatosensory inputs, accounts for secondary hyperalgesia, a typical sign of several painful clinical conditions. Brain potentials elicited by mechanical punctate stimulation using flat-tip probes can provide neural correlates of CS, but their signal-to-noise ratio is limited by poor synchronization of the afferent nociceptive input. Additionally, mechanical punctate stimulation does not activate nociceptors exclusively. In contrast, low-intensity intraepidermal electrical stimulation (IES) allows selective activation of type II Aδ-mechano-heat nociceptors (II-AMHs) and elicits reproducible brain potentials. However, it is unclear whether hyperalgesia from IES occurs and coexists with secondary mechanical punctate hyperalgesia, and whether the magnitude of the electroencephalographic (EEG) responses evoked by IES within the hyperalgesic area is increased. To address these questions, we explored the modulation of the psychophysical and EEG responses to IES by intraepidermal injection of capsaicin in healthy human subjects. We obtained three main results. First, the intensity of the sensation elicited by IES was significantly increased in participants who developed robust mechanical punctate hyperalgesia after capsaicin injection (i.e., responders), indicating that hyperalgesia from IES coexists with punctate mechanical hyperalgesia. Second, the N2 peak magnitude of the EEG responses elicited by IES was significantly increased after the intraepidermal injection of capsaicin in responders only. Third, a receiver-operator characteristics analysis showed that the N2 peak amplitude is clearly predictive of the presence of CS. These findings suggest that the EEG responses elicited by IES reflect secondary hyperalgesia and therefore represent an objective correlate of CS.


Subject(s)
Afferent Pathways/physiology , Brain/physiology , Electric Stimulation/methods , Evoked Potentials, Somatosensory/physiology , Pain/physiopathology , Skin/innervation , Adult , Capsaicin/toxicity , Central Nervous System Sensitization/physiology , Electroencephalography , Female , Humans , Hyperalgesia/chemically induced , Hyperalgesia/physiopathology , Male , Nociceptors/physiology , Pain/chemically induced , Pain Measurement , ROC Curve , Reaction Time/physiology , Signal-To-Noise Ratio , Young Adult
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