Recent Research Articles from UNTHSC
J Immigr Minor Health. 2021 Jul 26. doi: 10.1007/s10903-021-01241-4. Online ahead of print.
This cross-sectional study explores the willingness to donate biospecimens for research purposes among six refugee communities in North Texas (spanning Myanmar, Central Africa, Somalia, Nepal, Arabic speaking countries, and others). Participants were asked four questions about biospecimen donation: (1) previously asked to donate, (2) ever agreed to donate, (3) willingness to donate for future research, and (4) what samples they would be willing to donate. Most participants (77%) were willing to donate biosamples for medical research; 58% were willing to donate samples. Fewer refugees from Somalia were willing to donate compared to immigrants from Myanmar, Central Africa, and Nepal (p < 0.01). Participants in the older age group (40 + years) were 3.2 times more likely to be willing for donation of biospecimens than the younger ones (OR 3.22, 95% CI 1.22, 8.55). Findings suggest refugees' willingness to participate in biospecimen donation which support intentional inclusion of multicultural populations into medical research.
Cyclooxygenase-dependent mechanisms mediate in part the anti-dilatory effects of perivascular adipose tissue in uterine arteries from pregnant rats
Pharmacol Res. 2021 Jul 23:105788. doi: 10.1016/j.phrs.2021.105788. Online ahead of print.
Uterine perivascular adipose tissue (PVAT) contributes to uterine blood flow regulation in pregnancy, at least in part, due to its effects on uterine artery reactivity. We tested the hypothesis that uterine PVAT modulates the balance between the contribution of nitric oxide synthase (NOS)- and cyclooxygenase (COX)-dependent pathways to acetylcholine (ACh)-induced relaxation in isolated uterine arteries. Concentration-response curves to ACh (1nM - 30µM) were performed on uterine arteries from pregnant and non-pregnant rats. Arteries were exposed to Krebs-Henseleit solution (control) or PVAT-conditioned media (PVATmedia) in the presence of the following inhibitors: L-NAME (NOS inhibitor), indomethacin (COX inhibitor), SC560 (COX-1 inhibitor), NS398 (COX-2 inhibitor), SQ 29,548 (thromboxane receptor (TP) inhibitor). In arteries incubated with PVATmedia, the presence of indomethacin increased ACh-induced relaxation, reversing the anti-dilatory effect of PVATmedia. NOS inhibition reduced ACh-induced relaxation in uterine arteries from pregnant rats, and exposure to PVATmedia did not change this effect. Selective inhibition of COX-1 but not COX-2 suppressed relaxation responses to ACh in control arteries. The presence of PVATmedia abolished the effect of COX-1 inhibition. Incubation of uterine arteries from pregnant rats with PVATmedia increased production of thromboxane B2 (TxB2, p=0.01) but thromboxane receptor (TP) inhibition did not affect the anti-dilatory properties of PVATmedia. In conclusion, inhibition of COX signaling suppressed the anti-dilatory effects of PVATmedia, while PVATmedia had no effect on the contribution of the NOS/NO pathway to ACh-induced relaxation in uterine arteries from pregnant rats, indicating that the anti-dilatory effects of uterine PVAT are mediated in part by COX-dependent mechanisms.
Alzheimers Dement. 2021 Jul 26. doi: 10.1002/alz.12404. Online ahead of print.
INTRODUCTION: No large-scale characterizations of neurofilament light chain (NfL) have been conducted in diverse populations.
METHODS: Baseline data were analyzed among n = 890 Mexican Americans and n = 813 non-Hispanic Whites from the multi-ethnic Health & Aging Brain among Latino Elders (HABLE) study. Plasma NfL was measured on the Simoa platform.
RESULTS: In unadjusted models, NfL was significantly associated with age (P < .001), hypertension (P < .001), dyslipidemia (P = .02), and diabetes (P < .001). Covarying for age and sex, NfL was associated with neurodegeneration (P < .001) and global amyloid burden levels (P = .02) in a subset with available data. NfL levels were significantly associated with diagnostic groups (Normal Cognition [NC], mild cognitive impairment [MCI], Dementia; P < .001); however, there was no cut-score that yielded acceptable diagnostic accuracy. NfL levels produced a sensitivity of 0.60 and specificity of 0.78 with negative predictive value of 89% for detecting amyloid positivity.
DISCUSSION: Plasma NfL levels are significantly impacted by age and medical co-morbidities that are common among older adults, which complicate its utility as a diagnostic biomarker.
Environ Sci Technol Lett. 2020 Aug 11;7(8):532-543. doi: 10.1021/acs.estlett.0c00255. Epub 2020 Jun 30.
This commentary presents a scientific basis for managing as one chemical class the thousands of chemicals known as PFAS (per- and polyfluoroalkyl substances). The class includes perfluoroalkyl acids, perfluoroalkylether acids, and their precursors; fluoropolymers and perfluoropolyethers; and other PFAS. The basis for the class approach is presented in relation to their physicochemical, environmental, and toxicological properties. Specifically, the high persistence, accumulation potential, and/or hazards (known and potential) of PFAS studied to date warrant treating all PFAS as a single class. Examples are provided of how some PFAS are being regulated and how some businesses are avoiding all PFAS in their products and purchasing decisions. We conclude with options for how governments and industry can apply the class-based approach, emphasizing the importance of eliminating non-essential uses of PFAS, and further developing safer alternatives and methods to remove existing PFAS from the environment.
Curr Dev Disord Rep. 2021 Mar;8(1):24-31. doi: 10.1007/s40474-020-00209-7. Epub 2020 Aug 19.
PURPOSE OF THE REVIEW: It is well-documented that individuals with DCD experience mental health problems, in both psychosocial and psychiatric domains. In this review, we propose a series of diverse options to improve mental health among individuals with DCD.
RECENT FINDINGS: Despite recognition of mental health problems in DCD, relatively little work has been done to develop effective interventions. There is an urgent need for action in this matter. We present and discuss options based on a societal perspective (awareness and understanding), parental perspective (access to services and resources), and child perspective (participation).
SUMMARY: In order to improve mental health, interventions must take into account multiple levels in a complex framework that includes community, family, and the individual. While more research on intervention effectiveness is necessary, researchers, practitioners, and community advocates can use existing initiatives as a starting point to address the urgent need for improving mental health in DCD.
Integrative physiological assessment of cerebral hemodynamics and metabolism in acute ischemic stroke
J Cereb Blood Flow Metab. 2021 Jul 26:271678X211033732. doi: 10.1177/0271678X211033732. Online ahead of print.
Restoring perfusion to ischemic tissue is the primary goal of acute ischemic stroke care, yet only a small portion of patients receive reperfusion treatment. Since blood pressure (BP) is an important determinant of cerebral perfusion, effective BP management could facilitate reperfusion. But how BP should be managed in very early phase of ischemic stroke remains a contentious issue, due to the lack of clear evidence. Given the complex relationship between BP and cerebral blood flow (CBF)-termed cerebral autoregulation (CA)-bedside monitoring of cerebral perfusion and oxygenation could help guide BP management, thereby improve stroke patient outcome. The aim of INFOMATAS is to 'identify novel therapeutic targets for treatment and management in acute ischemic stroke'. In this review, we identify novel physiological parameters which could be used to guide BP management in acute stroke, and explore methodologies for monitoring them at the bedside. We outline the challenges in translating these potential prognostic markers into clinical use.
Factors Related to the Accurate Application of NHSN Surveillance Definitions for CAUTI and CLABSI in Texas Hospitals: A Cross-Sectional Survey
Am J Infect Control. 2021 Jul 22:S0196-6553(21)00482-X. doi: 10.1016/j.ajic.2021.07.007. Online ahead of print.
Previous studies indicate variability in the accurate application of National Healthcare Safety Network (NHSN) surveillance criteria with limited data on possible contributing factors. In this cross-sectional, convenience sampled web-based survey sent to members of Texas infection prevention and control organizations, training, experience, and time spent on surveillance was collected and assessed including two case studies. Our results indicate correct identification of catheter-associated urinary tract infection (CAUTI) and central line-associated bloodstream infection (CLABSI) criteria may be associated with 2019 NHSN training (CAUTI: aOR = 0.17, 95% CI: 0.04, 0.80; CLABSI: aOR = 0.45, 95% CI: 0.045, 4.56) and increased years of infection prevention experience (CAUTI: aOR = 1.35, 95% CI: 0.42, 4.33; CLABSI: aOR = 1.23, 95% CI: 0.24, 6.38). Routinely performing more hours of surveillance may increase accuracy of CLABSI identification, but not CAUTI.
Testing daily-level drinking and negative consequences as predictors of next-day drinking cognitions
Addict Behav. 2021 Jul 8;122:107042. doi: 10.1016/j.addbeh.2021.107042. Online ahead of print.
OBJECTIVE: Limited research has examined how alcohol use and related consequences affect drinking-related cognitions, which is important as these cognitions may contribute to future drinking. The current study examines daily associations between alcohol use and alcohol-related negative consequences with next-day Prototype Willingness Model (PWM) social reaction pathway cognitions.
METHOD: Participants ages 15-25 years (N = 124, Mean age 18.7, SD = 2.87) completed daily surveys for up to three weeks (i.e., up to 11 surveys/week) using an ecological momentary assessment design. Linear mixed models and Poisson generalized mixed models were conducted to examine whether number of alcoholic drinks or number of negative alcohol-related consequences were associated with next-day PWM social reaction cognitions, including perceived vulnerability, descriptive normative perceptions of number of drinks consumed and the percentage of friends who drink, prototype favorability, prototype similarity, and willingness (i.e., openness) to drink.
RESULTS: Within-person results indicated more alcohol use on a given day was associated with lower next-day normative perceptions of the percentage of friends who drink on that day of the week and higher prototype similarity. Furthermore, within-person results indicated that experiencing more negative alcohol-related consequences on a given day was associated with higher perceived vulnerability and lower willingness to drink the next day.
CONCLUSIONS: Findings showed that next-day social reaction PWM cognitions were associated with prior day alcohol use and negative alcohol-related consequences, suggesting that an intervention might be timed to target drinking cognitions the morning following a drinking event, particularly after experiencing negative alcohol-related consequences.
Am J Pharm Educ. 2021 Jul 22:8562. doi: 10.5688/ajpe8562. Online ahead of print.
Objective. Within pharmacy experiential education, practicing literature evaluation skills usually occurs via journal clubs. Clinical debates have gained traction as an engaging alternative during advanced pharmacy practice experiences (APPEs). The purpose of this study was to compare clinical knowledge and literature evaluation application between journal clubs and clinical debates during APPEs.Methods. This mixed-methods prospective study was conducted in fourth year pharmacy students completing inpatient general medicine APPEs at four institutions. Students participated in a journal club and clinical debate during their experience. After each, students completed a 10-item knowledge assessment. Differences in journal club and clinical debate assessment scores were analyzed. Following completion of both activities, a perception survey was administered to gauge preferences and opinions. Differences in perception survey scores for journal clubs compared to clinical debates were evaluated quantitatively and a thematic analysis was completed for qualitative responses.Results. Fifty students participated in both activities. There were no differences between journal club and clinical debate assessment scores (57.4 ± 21.0% and 62.9 ± 20.7%, respectively). Forty students completed the post-perceptions survey and globally agreed or strongly agreed that both journal clubs and clinical debates improved confidence in literature evaluation and clinical skills. Common themes identified included applicability to pharmacists' roles and need for clear instructions and examples.Conclusion. There was no difference in knowledge assessments of journal clubs versus clinical debates and students found both activities to be beneficial. Clinical debates are a reasonable alternative to journal clubs to improve knowledge and literature evaluation skills.
Effect of Dimer Structure and Inhomogeneous Broadening of Energy Levels on the Action of Flavomononucleotide in Rigid Polyvinyl Alcohol Films
Int J Mol Sci. 2021 Jul 20;22(14):7759. doi: 10.3390/ijms22147759.
The results of time-resolved fluorescence measurements of flavin mononucleotide (FMN) in rigid polyvinyl alcohol films (PVA) demonstrate that fluorescence intensity decays are strongly accelerated in the presence of fluorescent dimers and nonradiative energy transfer processes. The fluorescence decay originating both from H and J dimer states of FMN was experimentally observed for the first time. The mean fluorescence lifetimes for FMN dimers were obtained: τfl = 2.66 ns (at λexc = 445 nm) and τfl = 2.02 (at λexc = 487 nm) at λobs = 600 nm and T = 253 K from H and J state of dimers, respectively. We show that inhomogeneous orientational broadening of energy levels (IOBEL) affects the shape of the fluorescence decay and leads to the dependence of the average monomer fluorescence lifetime on excitation wavelength. IOBEL affected the nonradiative energy transfer and indicated that different flavin positioning in the protein pocket could (1) change the spectroscopic properties of flavins due to the existence of "blue" and "red" fluorescence centers, and (2) diminish the effectiveness of energy transfer between FMN molecules.
Cancers (Basel). 2021 Jul 9;13(14):3445. doi: 10.3390/cancers13143445.
Akt, also known as protein kinase B (PKB), belongs to the AGC family of protein kinases. It acts downstream of the phosphatidylinositol 3-kinase (PI3K) and regulates diverse cellular processes, including cell proliferation, cell survival, metabolism, tumor growth and metastasis. The PI3K/Akt signaling pathway is frequently deregulated in breast cancer and plays an important role in the development and progression of breast cancer. There are three closely related members in the Akt family, namely Akt1(PKBα), Akt2(PKBβ) and Akt3(PKBγ). Although Akt isoforms share similar structures, they exhibit redundant, distinct as well as opposite functions. While the Akt signaling pathway is an important target for cancer therapy, an understanding of the isoform-specific function of Akt is critical to effectively target this pathway. However, our perception regarding how Akt isoforms contribute to the genesis and progression of breast cancer changes as we gain new knowledge. The purpose of this review article is to analyze current literatures on distinct functions of Akt isoforms in breast cancer.
NRMNet: Building a National Resource for Mentorship, Networking and Professional Development to Enhance Diversity
Ethn Dis. 2021 Jul 15;31(3):469-480. doi: 10.18865/ed.31.3.469. eCollection 2021 Summer.
BACKGROUND: To address the need for diversifying the biomedical research workforce, the National Institutes of Health (NIH) established the Diversity Program Consortium (DPC) with the goal of developing, implementing, assessing, and disseminating interventions and programs to enhance the participation and persistence of individuals from underrepresented backgrounds in biomedical research careers.
INTERVENTION: As part of the DPC initiative, the NIH funded the National Research Mentoring Network (NRMN), which aimed to increase diversity of the biomedical research workforce through culturally responsive mentorship, networking, and professional development. In 2015, the NRMNet portal was developed to provide a broad-based network of mentors who are accessible to diverse mentees across the country. The portal also provides networking and professional development resources that support mentee transitions from one career stage to the next.
RESULTS: NRMNet is the gateway for career stage-specific mentorship, networking, resources, and professional development programs for trainees across the biomedical, behavioral, clinical, and social sciences. In the first five years, the NRMN strategic recruitment efforts resulted in an expanded network of nearly 13,000 diverse mentors and mentees with NRMN representation in all 50 states and Puerto Rico. Consistently, over the first five years, racial and ethnic diversity was reflected in composition of mentee and mentor groups: 66% of 6,526 mentees and 33% of 3,866 mentors were from underrepresented groups.
CONCLUSIONS: The NRMNet portal is a promising effort for enhancing participation and continued engagement of undrerepresented individuals in biomedical research careers by providing culturally responsive mentorship, networking, and professional development for individuals at all career stages.
Intermittent Hypoxia Training Prevents Deficient Learning-Memory Behavior in Mice Modeling Alzheimer's Disease: A Pilot Study
Front Aging Neurosci. 2021 Jul 1;13:674688. doi: 10.3389/fnagi.2021.674688. eCollection 2021.
In mouse models of Alzheimer's disease (AD), normobaric intermittent hypoxia training (IHT) can preserve neurobehavioral function when applied before deficits develop, but IHT's effectiveness after onset of amyloid-β (Aβ) accumulation is unclear. This study tested the hypothesis that IHT improves learning-memory behavior, diminishes Aβ accumulation in cerebral cortex and hippocampus, and enhances cerebrocortical contents of the neuroprotective trophic factors erythropoietin and brain-derived neurotrophic factor (BDNF) in mice manifesting AD traits. Twelve-month-old female 3xTg-AD mice were assigned to untreated 3xTg-AD (n = 6), AD+IHT (n = 6), and AD+sham-IHT (n = 6) groups; 8 untreated wild-type (WT) mice also were studied. AD+IHT mice alternately breathed 10% O2 for 6 min and room air for 4 min, 10 cycles/day for 21 days; AD+sham-IHT mice breathed room air. Spatial learning-memory was assessed by Morris water maze. Cerebrocortical and hippocampal Aβ40 and Aβ42 contents were determined by ELISA, and cerebrocortical erythropoietin and BDNF were analyzed by immunoblotting and ELISA. The significance of time (12 vs. 12 months + 21 days) and treatment (IHT vs. sham-IHT) was evaluated by two-factor ANOVA. The change in swimming distance to find the water maze platform after 21 d IHT (-1.6 ± 1.8 m) differed from that after sham-IHT (+5.8 ± 2.6 m). Cerebrocortical and hippocampal Aβ42 contents were greater in 3xTg-AD than WT mice, but neither time nor treatment significantly affected Aβ40 or Aβ42 contents in the 3xTg-AD mice. Cerebrocortical erythropoietin and BDNF contents increased appreciably after IHT as compared to untreated 3xTg-AD and AD+sham-IHT mice. In conclusion, moderate, normobaric IHT prevented spatial learning-memory decline and restored cerebrocortical erythropoietin and BDNF contents despite ongoing Aβ accumulation in 3xTg-AD mice.
Influence of Ischemia-reperfusion Injury on Endothelial Function in Men and Women with Similar Serum Estradiol Concentrations
Am J Physiol Regul Integr Comp Physiol. 2021 Jul 14. doi: 10.1152/ajpregu.00147.2021. Online ahead of print.
Prior data suggest that relative to the early follicular phase, women in the late follicular phase are protected against endothelial ischemia-reperfusion (I/R) injury when estradiol concentrations are highest. In addition, endothelial I/R injury is consistently observed in men with naturally low endogenous estradiol concentrations that are similar to women in the early follicular phase. Therefore, the purpose of this study was to determine if the vasodeleterious effect of I/R injury differs between women in the early follicular phase of the menstrual cycle and age-matched men. We tested the hypothesis that I/R injury would attenuate endothelium-dependent vasodilation to the same extent in women and age-matched men with similar circulating estradiol concentrations. Endothelium-dependent vasodilation was assessed via brachial artery flow-mediated dilation (duplex ultrasound) in young healthy men (N = 22) and women (N = 12) before (pre-I/R) and immediately after I/R injury (post-I/R), which was induced via 20 min of arm circulatory arrest followed by 20 min reperfusion. Serum estradiol concentrations did not differ between sexes (men, 115.0 ± 33.9 pg ml-1 vs. women, 90.5 ± 40.8 pg ml-1; P = 0.2). The magnitude by which I/R injury attenuated endothelium-dependent vasodilation did not differ between men (pre-I/R, 5.4 ± 2.4 % vs. post-I/R 3.0 ± 2.7 %;) and women (pre-I/R, 6.1 ± 2.8 % vs. post-I/R 3.7 ± 2.7 %; P = 0.9). Our data demonstrate that I/R injury similarly reduces endothelial function in women in the early follicular phase of the menstrual cycle and age-matched men with similar estradiol concentrations.
J Opioid Manag. 2021 May-Jun;17(3):215-225. doi: 10.5055/jom.2021.0632.
OBJECTIVE: Examine the relationship between prescription opioid analgesic use during pregnancy and preterm birth or term low birthweight.
DESIGN, SETTING, AND PARTICIPANTS: We analyzed data from the National Birth Defects Prevention Study, a US multisite, population-based study, for births from 1997 to 2011. We defined exposure as self-reported prescription opioid use between one month before conception and the end of pregnancy, and we dichotomized opioid use duration by ≤7 days and >7 days.
MAIN OUTCOME MEASURES: We examined the association between opioid use and preterm birth (defined as gestational age <37 weeks) and term low birthweight (defined as <2500 g at gestational age ≥37 weeks).
RESULTS: Among 10,491 singleton mother/infant pairs, 470 (4.5 percent) reported opioid use. Among women reporting opioid use, 236 (50 percent) used opioids for > 7 days; codeine (170, 36 percent) and hydrocodone (163, 35 percent) were the most commonly reported opioids. Opioid use was associated with slightly increased risk for preterm birth [adjusted odds ratio, 1.4; 95 percent confidence interval, 1.0, 1.9], particularly with hydrocodone [1.6; 1.0, 2.6], meperidine [2.5; 1.2, 5.2], or morphine [3.0; 1.5, 6.1] use for any duration; however, opioid use was not significantly associated with term low birthweight.
CONCLUSIONS: Preterm birth occurred more frequently among infants of women reporting prescription opioid use during pregnancy. However, we could not determine if these risks relate to the drug or to indications for use. Patients who use opioids during pregnancy should be counseled by their practitioners about this and other potential risks associated with opioid use in pregnancy.
J Cereb Blood Flow Metab. 2021 Jul 14:271678X211032029. doi: 10.1177/0271678X211032029. Online ahead of print.
Optimizing cerebral perfusion is key to rescuing salvageable ischemic brain tissue. Despite being an important determinant of cerebral perfusion, there are no effective guidelines for blood pressure (BP) management in acute stroke. The control of cerebral blood flow (CBF) involves a myriad of complex pathways which are largely unaccounted for in stroke management. Due to its unique anatomy and physiology, the cerebrovascular circulation is often treated as a stand-alone system rather than an integral component of the cardiovascular system. In order to optimize the strategies for BP management in acute ischemic stroke, a critical reappraisal of the mechanisms involved in CBF control is needed. In this review, we highlight the important role of collateral circulation and re-examine the pathophysiology of CBF control, namely the determinants of cerebral perfusion pressure gradient and resistance, in the context of stroke. Finally, we summarize the state of our knowledge regarding cardiovascular and cerebrovascular interaction and explore some potential avenues for future research in ischemic stroke.
MyNRMN: A national mentoring and networking platform to enhance connectivity and diversity in the biomedical sciences
FASEB Bioadv. 2021 Mar 31;3(7):497-509. doi: 10.1096/fba.2020-00102. eCollection 2021 Jul.
AIMS: Increasing the diversity of the biomedical sciences workforce is a national priority. Having a mentor, and more crucially, a personal network of mentors, improves the likelihood that an individual will pursue an advanced degree and career in the biomedical sciences. The chief mission of the National Research Mentoring Network (NRMN) is to reduce racial and ethnic disparities in the biosciences workforce through the mentoring of historically underrepresented individuals.
METHODS: To address this need, we created MyNRMN, an online mentoring platform that connects mentors and mentees nationwide. The platform enables multiple forms of mentoring and recommends connections to mentees that will help them build their personal networks.
RESULTS: The MyNRMN online platform has registered more than 13,500 active mentors and mentees across all 50 states and from more than 2100 institutions. Black and Hispanic mentees are highly represented.
DISCUSSION: MyNRMN has expanded opportunities for mentorship in the biomedical sciences, particularly among those not from a culture or institution that historically supports mentorship. The platform's robust search and recommendation capabilities and graph database technology enable members to grow their personal network of mentors.
CONCLUSION: The MyNRMN online platform has proven successful in connecting mentees and mentors nationwide, expanding the pipeline in biomedical science careers to attract a more diverse workforce.
Community Dent Oral Epidemiol. 2021 Jul 12. doi: 10.1111/cdoe.12678. Online ahead of print.
OBJECTIVES: Healthcare (including dental care) service use is influenced by predisposing, enabling and need factors. One area with limited research is the association of acculturation (defined as behavioural changes in the adaptation to another culture) as a predisposing factor for dental care preventive service use. Preventive service use is a primary objective of Healthy People, 2030. The purpose of this study was to determine the association of acculturation with the preventive dental service use of dental pit-and-fissure sealant placement, among children in the United States, ages 6-18 years.
METHODS: A cross-sectional, secondary data analysis study was completed using National Health and Nutrition Examination Survey (NHANES), 2013-2016 data. NHANES is a nationally representative survey of noninstitutionalized individuals across the United States. In the data set, children, ages 6-18 years, had been evaluated for pit-and-fissure dental sealant use. Information that served as proxies for acculturation was length of stay in the United States (a citizen at the time of the survey; not a citizen and in the country <5 years; or not a citizen and in the country ≥5 years) and whether English was spoken at home (yes; no). Data were analysed for descriptive statistics. Multivariable logistic regressions were used to examine strength of the associations. Odds ratios for pit-and-fissure sealants among groups were determined.
RESULTS: There were 2220 children participants whose data were used for this study. Less than half (45.5%) had received dental pit-and-fissure sealants. A majority (53.3%) were white and were ages 12-18 years (51.6%). The mean number of dental pit-and-fissure sealants among all children was 5.5. There was a lower percentage of children living in the United States <5 years who had received pit-and-fissure sealants than children who were citizens of the United States (22.2% vs 48.9%, respectively). The adjusted odds ratio was lower for dental pit-and-fissure sealants among children who were in the United States <5 years than children who were citizens of the United States (adjusted odds ratio, 0.38; 95% Confidence Interval: 0.24, 0.58).
CONCLUSIONS: In this study, children who had lived in the United States <5 years were less likely to have pit-and-fissure sealants than children who were citizens of the United States. There is a need to reach all children with preventive services to improve dental quality of life, reduce the need for dental restorations and decrease overall financial burden regardless of time in the United States.
J Physiol. 2021 Jul 10. doi: 10.1113/JP281730. Online ahead of print.
KEY POINTS: Humans suffering from polycythaemia undergo multiple circulatory adaptations including changes in blood rheology and structural and functional vascular adaptations to maintain normal blood pressure and vascular shear stresses, despite high blood viscosity. During exercise, several circulatory adaptations are observed, especially involving adrenergic and non-adrenergic mechanisms within non-active and active skeletal muscle to maintain exercise capacity, which is not observed in animal models. Despite profound circulatory stress, i.e., polycythaemia, several adaptations can occur to maintain exercise capacity, therefore making early identification of the disease difficult without overt symptomology. Pharmacological treatment of the background heightened sympathetic activity may impair the adaptive sympathetic response needed to match local oxygen delivery to active skeletal muscle oxygen demand and therefore inadvertently impair exercise capacity.
ABSTRACT: Excessive haematocrit and blood viscosity can increase blood pressure, cardiac work and reduce aerobic capacity. However, past clinical investigations have demonstrated that certain human high-altitude populations suffering from excessive erythrocytosis, Andeans with chronic mountain sickness, appear to have phenotypically adapted to life with polycythaemia, as their exercise capacity is comparable to healthy Andeans and even with sea level inhabitants residing at high altitude. By studying this unique population, which has adapted thru natural selection, this study aimed to describe how humans can adapt to life with polycythaemia. Experimental studies included Andeans with (n = 19) and without (n = 17) chronic mountain sickness, documenting exercise capacity, and characterizing the transport of oxygen thru blood rheology, including haemoglobin mass, blood and plasma volume & blood viscosity, cardiac output, blood pressure and changes in total and local vascular resistances thru pharmacological dissected of α-adrenergic signalling pathways within non-active and active skeletal muscle. At rest, Andeans with chronic mountain sickness had a substantial plasma volume contraction, which alongside a higher red blood cell volume, caused an increase in blood viscosity yet similar total blood volume. Moreover, both morphological and functional alterations in the periphery normalized vascular shear stress and blood pressure despite high sympathetic nerve activity. During exercise, blood pressure, cardiac work and global oxygen delivery increased similar to healthy Andeans but were sustained by modifications in both non-active and active skeletal muscle vascular function. These findings highlight widespread physiological adaptations that can occur in response to polycythaemia, which allow the maintenance of exercise capacity. This article is protected by copyright. All rights reserved.