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1.
J Clin Psychol ; 80(1): 65-85, 2024 01.
Article in English | MEDLINE | ID: mdl-37659101

ABSTRACT

OBJECTIVES: Rates of suicide exposure are high among service members and Veterans and are especially concerning given the link between suicide exposure and subsequent suicide risk. However, to date, it is unclear which individuals who are exposed to suicide are subsequently at high risk for suicide. Latent profile analysis (LPA) can provide information on unique risk profiles and subgroups of service members and Veterans who have higher suicide risk after suicide exposure, which has not yet been empirically studied. The purpose of this study was to utilize LPA to identify subgroups of service members and Veterans who are at the highest risk for suicidal thoughts and behaviors following suicide exposure. METHODS: We analyzed data using LPA from 2570 service members and Veterans (82.1% male, 69.5% White, and 12.1% Latino/a/x) who completed the Military Suicide Research Consortium's Common Data Elements, a battery of self-report suicide-related measures. Psychopathology, substance use, mental health service utilization, interpersonal theory of suicide, and suicide exposure variables were used to validate classes. RESULTS: Three latent classes emerged from analyses, one low-risk class and two-high risk classes with differing profile compositions (one primarily differentiated by anxiety symptoms and one differentiated by substance use). CONCLUSION: Class-specific recommendations for suicide prevention efforts will be discussed.


Subject(s)
Military Personnel , Substance-Related Disorders , Suicide , Veterans , Male , Humans , Female , Veterans/psychology , Suicide/psychology , Military Personnel/psychology , Suicidal Ideation , Risk Factors
2.
Metabolites ; 13(11)2023 Nov 09.
Article in English | MEDLINE | ID: mdl-37999235

ABSTRACT

Matrix-assisted laser desorption/ionization mass spectrometry imaging allows for the study of metabolic activity in the tumor microenvironment of brain cancers. The detectable metabolites within these tumors are contingent upon the choice of matrix, deposition technique, and polarity setting. In this study, we compared the performance of three different matrices, two deposition techniques, and the use of positive and negative polarity in two different brain cancer types and across two species. Optimal combinations were confirmed by a comparative analysis of lipid and small-molecule abundance by using liquid chromatography-mass spectrometry and RNA sequencing to assess differential metabolites and enzymes between normal and tumor regions. Our findings indicate that in the tumor-bearing brain, the recrystallized α-cyano-4-hydroxycinnamic acid matrix with positive polarity offered superior performance for both detected metabolites and consistency with other techniques. Beyond these implications for brain cancer, our work establishes a workflow to identify optimal matrices for spatial metabolomics studies.

3.
Risk Manag Healthc Policy ; 16: 1693-1702, 2023.
Article in English | MEDLINE | ID: mdl-37670731

ABSTRACT

The COVID-19 pandemic exposed the limitations of global health systems' abilities to manage the rapid spread of a novel infectious disease, which was exacerbated by shortages of respiratory protective devices and other critical personal protective equipment (PPE). An advisory panel of experienced health-care professionals with backgrounds in Occupational and Environmental Health and Safety (OEHS), Infection Prevention, Nursing, and Clinical Application Specialists convened to discuss challenges and strategies associated with the selection and use of respiratory protective devices as experienced during the first year of the COVID-19 pandemic. This discussion led to the following recommendations: 1) the need for clear communication of alternative respiratory protection selection and use recommendations in accordance with US regulatory and agency guidance; 2) the need for collaboration between Infection Prevention, OEHS, clinical staff, supply chain/materials management, emergency preparedness, executive leadership, and finance; 3) the need for adequate stockpiling, inventory rotation, and diverse respiratory protection options to accommodate the majority of health-care workers; 4) the need for efficient and innovative strategies to communicate evolving regulatory, agency, and facility recommendations and to deliver appropriate training on respiratory protection; and 5) the need for additional research on respiratory protection use - involving filtering facepiece respirators (FFRs) as well as other respirator types designed to be reused - to balance infection prevention best practices with a sustainable process. In conclusion, these considerations may offer guidance and identify areas for research on preparedness, communication, education, and training to enhance the preparation of health-care facilities including community-based health-care organizations for unexpected public health events.

4.
Alzheimers Dement (N Y) ; 9(3): e12413, 2023.
Article in English | MEDLINE | ID: mdl-37521522

ABSTRACT

Introduction: Increased availability of Alzheimer's disease (AD) biomarker tests provides older adults with opportunities to seek out and learn results. We evaluated the feasibility of virtually returning AD biomarker results. Methods: Trained study clinicians disclosed amyloid positron emission tomography (PET) results and provided dementia risk-reduction counseling via televideo to cognitively unimpaired participants already enrolled in AD research (n = 99; mean age ± SD: 72.0 ± 4.8; 67% women; 95% White; 28% amyloid elevated). Results: Our study demonstrated acceptable levels of retention (93%), compliance (98%), adherence (98%), clinician competence (97%), education comprehension (quiz scores 14/15), and virtual visit functionality (rating 9.4/10). Depression, anxiety, and suicidality remained low and did not differ by amyloid result. Discussion: Virtual return of amyloid PET results to cognitively unimpaired research participants is feasible and does not result in increased psychological symptoms. Technological barriers for some participants highlight the need for flexibility. These findings support the use of televideo in AD biomarker disclosure, although our study sample and design have important limitations for generalizability.

5.
Crisis ; 44(1): 7-13, 2023 Jan.
Article in English | MEDLINE | ID: mdl-34128700

ABSTRACT

Background: Suicide risk following youth psychiatric hospitalization is of significant concern. This study evaluated Linking Individuals Needing Care (LINC), a theory-driven, comprehensive care coordination approach for youth discharged from crisis services. Aims: To pilot LINC's potential effectiveness in increasing service utilization and decreasing suicide risk. Method: Participants were 460 youth patients who received LINC for approximately 90 days following discharge from crisis services. Service utilization, depressive symptoms, and suicide-related variables were measured at baseline and 30, 60, and 90 days after baseline. Results: Patients significantly increased the use of various beneficial, least restrictive services (individual therapy, medication management, and non-mental health supports) over the 90-day intervention. Significant decreases were observed in depressive symptoms, suicide ideation, and engagement in suicide-related behaviors. Limitations: Absence of a comparison group and nonparticipating families limit causal conclusions and generalizability. Conclusions: LINC may be a promising new approach following inpatient hospitalization that can engage and retain youth in services, likely resulting in improved treatment outcomes. This approach was designed emphasizing patient engagement, suicide risk assessment and management, safety planning, community networking, referral/linkage monitoring, coping and motivational strategies, and linguistic/culturally responsive practices to meet service and support needs of high-risk suicidal youth.


Subject(s)
Patient Discharge , Suicide, Attempted , Humans , Adolescent , Suicide, Attempted/psychology , Inpatients , Suicidal Ideation , Hospitalization
6.
Int J Mol Sci ; 23(19)2022 Oct 06.
Article in English | MEDLINE | ID: mdl-36233149

ABSTRACT

SARS-CoV-2 is the cause of the COVID-19 pandemic which has claimed more than 6.5 million lives worldwide, devastating the economy and overwhelming healthcare systems globally. The development of new drug molecules and vaccines has played a critical role in managing the pandemic; however, new variants of concern still pose a significant threat as the current vaccines cannot prevent all infections. This situation calls for the collaboration of biomedical scientists and healthcare workers across the world. Repurposing approved drugs is an effective way of fast-tracking new treatments for recently emerged diseases. To this end, we have assembled and curated a database consisting of 7817 compounds from the Compounds Australia Open Drug collection. We developed a set of eight filters based on indicators of efficacy and safety that were applied sequentially to down-select drugs that showed promise for drug repurposing efforts against SARS-CoV-2. Considerable effort was made to evaluate approximately 14,000 assay data points for SARS-CoV-2 FDA/TGA-approved drugs and provide an average activity score for 3539 compounds. The filtering process identified 12 FDA-approved molecules with established safety profiles that have plausible mechanisms for treating COVID-19 disease. The methodology developed in our study provides a template for prioritising drug candidates that can be repurposed for the safe, efficacious, and cost-effective treatment of COVID-19, long COVID, or any other future disease. We present our database in an easy-to-use interactive interface (CoviRx that was also developed to enable the scientific community to access to the data of over 7000 potential drugs and to implement alternative prioritisation and down-selection strategies.


Subject(s)
COVID-19 Drug Treatment , COVID-19 , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/complications , Drug Repositioning , Humans , Pandemics , SARS-CoV-2 , Post-Acute COVID-19 Syndrome
7.
Death Stud ; 46(5): 1176-1185, 2022.
Article in English | MEDLINE | ID: mdl-32762420

ABSTRACT

Veteran and service member suicide remains a significant public health concern. One factor that may impact suicide risk is suicide exposure-knowing someone who has died by suicide or attempted suicide. However, the majority of the extant literature has focused on nonmilitary samples, which may not generalize to military veterans and service members. The current review synthesizes findings regarding suicide exposure in military veterans, service members, their families, and military systems. Our review suggests that the relationship between suicide exposure, suicide risk, and mental health outcomes remains inconsistent. Future research should further explore this important area.


Subject(s)
Military Family , Military Personnel , Veterans , Humans , Military Personnel/psychology , Risk Factors , Suicide, Attempted , Veterans/psychology , Violence
8.
Arch Suicide Res ; 26(3): 1378-1394, 2022.
Article in English | MEDLINE | ID: mdl-33871314

ABSTRACT

Suicide rates continue to rise, and clinicians and mental health staff play a critical role in keeping suicidal clients safe. Safety planning, including means safety, may help to decrease suicide risk. Unfortunately, availability and evaluation of safety planning training for these providers are scarce. The goal of the present study was to evaluate a safety planning training, LINC to LIFE Safety Planning (L2L SP). L2L SP is a 150-minute, face-to-face training program that teaches providers to engage clients in collaborative safety planning and means safety efforts, facilitate diverse client coping strategies, problem-solve, and involve close others, among other skills. These objectives are achieved through interactive content delivery, role-play, and corrective feedback. L2L SP was administered to 95 participants. Key determinants of behavioral change (e.g., knowledge, attitudes, perceived behavioral control [PBC]) were measured at pre, post, and six-month follow-up. Additionally, participants' behaviors and emotions in working with suicidal clients were measured at pretest and six-month follow-up. Paired sample t-tests, repeated measures MANOVA, and univariate ANOVAs with post-hoc testing using Bonferroni correction were conducted. Results supported significant improvements in knowledge, PBC, and intentions at post-test, and attitudes, PBC, and effective emotional responses at follow-up. Exploratory analyses suggested significant improvements in behaviors among clinicians and mental health staff who saw clients reporting suicidal ideation. The present study provides promising results regarding brief safety planning training. Declines in knowledge and PBC following the training highlight the potential need for booster sessions or more intensive initial training in these areas.HighlightsThe present study evaluated a comprehensive, interactive safety planning training.Knowledge, PBC, and intentions were significantly improved at post-test.Attitudes, PBC, and emotions were significantly improved at follow-up.


Subject(s)
Mental Health , Suicide Prevention , Suicide , Adaptation, Psychological , Attitude , Humans , Suicidal Ideation , Suicide/psychology
9.
Elife ; 102021 07 07.
Article in English | MEDLINE | ID: mdl-34232857

ABSTRACT

Most eukaryotic mRNAs accommodate alternative sites of poly(A) addition in the 3' untranslated region in order to regulate mRNA function. Here, we present a systematic analysis of 3' end formation factors, which revealed 3'UTR lengthening in response to a loss of the core machinery, whereas a loss of the Sen1 helicase resulted in shorter 3'UTRs. We show that the anti-cancer drug cordycepin, 3' deoxyadenosine, caused nucleotide accumulation and the usage of distal poly(A) sites. Mycophenolic acid, a drug which reduces GTP levels and impairs RNA polymerase II (RNAP II) transcription elongation, promoted the usage of proximal sites and reversed the effects of cordycepin on alternative polyadenylation. Moreover, cordycepin-mediated usage of distal sites was associated with a permissive chromatin template and was suppressed in the presence of an rpb1 mutation, which slows RNAP II elongation rate. We propose that alternative polyadenylation is governed by temporal coordination of RNAP II transcription and 3' end processing and controlled by the availability of 3' end factors, nucleotide levels and chromatin landscape.


Subject(s)
Poly A/chemistry , Polyadenylation , Saccharomyces cerevisiae/metabolism , 3' Untranslated Regions , DNA Helicases , Kinetics , RNA Helicases , Saccharomyces cerevisiae/chemistry , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae Proteins
10.
Mol Omics ; 17(4): 583-595, 2021 08 01.
Article in English | MEDLINE | ID: mdl-34105576

ABSTRACT

Macrophages have important roles in the immune system including clearing pathogens and wound healing. Metabolic phenotypes in macrophages have been associated with functional phenotypes, where pro-inflammatory macrophages have an increased rate of glycolysis and anti-inflammatory macrophages primarily use oxidative phosphorylation. ß-adrenoceptor (ßAR) signalling in macrophages has been implicated in disease states such as cancer, atherosclerosis and rheumatoid arthritis. The impact of ßAR signalling on macrophage metabolism has not been defined. Using metabolomics and proteomics, we describe the impact of ßAR signalling on macrophages treated with isoprenaline. We found that ßAR signalling alters proteins involved in cytoskeletal rearrangement and redox homeostasis of the cell. We showed that ßAR signalling in macrophages shifts glucose metabolism from glycolysis towards the tricarboxylic acid cycle and pentose phosphate pathways. We also show that ßAR signalling perturbs purine metabolism by accumulating adenylate and guanylate pools. Taken together, these results indicate that ßAR signalling shifts metabolism to support redox processes and upregulates proteins involved in cytoskeletal changes, which may contribute to ßAR effects on macrophage function.


Subject(s)
Macrophages , Signal Transduction , Glycolysis , Receptors, Adrenergic
11.
Biomed Opt Express ; 12(2): 1167-1180, 2021 Feb 01.
Article in English | MEDLINE | ID: mdl-33680565

ABSTRACT

Lasers with ultrashort pulse durations have become ubiquitous in various applications, including ocular surgery. Therefore, we need to consider the role of nonlinear optical effects, such as supercontinuum generation during propagation within the ocular media, when evaluating their potential hazard. We used a NIR femtosecond laser to generate a supercontinuum within an artificial eye. We recorded the visible spectra of the supercontinuum generated and calculated the energy contained within the visible band. Our results indicate that for wavelengths between 1350 nm and 1450 nm the energy contained within the visible band of the generated white light supercontinuum may surpass current safety exposure limits, and pose a risk of injury to the retina.

12.
Arch Sex Behav ; 50(3): 1003-1014, 2021 04.
Article in English | MEDLINE | ID: mdl-33599884

ABSTRACT

Individuals who identify as lesbian, gay, bisexual, transgender, or queer (LGBTQ) are at a higher risk for suicidality compared to the general population. A growing body of research has investigated this risk, particularly with attention to systemic factors such as discrimination and harassment. Unfortunately, research has only examined the impact of direct discrimination on suicidality and has neglected to examine how ambient discrimination (i.e., witnessing or being made aware of discriminatory behaviors directed at someone other than yourself in your group) relates to suicidality. Additionally, although some links exist between discrimination and suicidality, the mechanisms by which these are related are understudied. This study aimed to address these gaps by exploring the effect of ambient discrimination on suicidal ideation and examining psychological pain as a mediator in this relationship. Data were collected from a sample of 200 LGBTQ-identified individuals (M age = 35 years; 53.5% female; 86% White). Results of independent t tests and a one-way multivariate ANOVA revealed greater vulnerability for ambient/direct discrimination and psychache among individuals identifying as transgender, queer, and other. Regression and mediation analyses revealed that while both ambient and direct discrimination predicted suicidal ideation, only direct discrimination accounted for unique variance in the outcome; however, both ambient and direct discrimination contributed unique variance to psychological pain, which fully mediated their relationships to suicidal ideation. Results of this study may begin to provide insight into the pathways of risk and points of intervention for suicidality in the LGBTQ community.


Subject(s)
Crime Victims , Prejudice , Sexual and Gender Minorities , Suicidal Ideation , Adult , Female , Humans , Male , Sexual and Gender Minorities/psychology , Sexual and Gender Minorities/statistics & numerical data , United States
13.
J Nutr Educ Behav ; 53(4): 343-351, 2021 04.
Article in English | MEDLINE | ID: mdl-33349594

ABSTRACT

OBJECTIVE: To assess the effectiveness of food-based science, technology, engineering, arts, and mathematics (STEAM) learning activities on preschoolers' liking of 9 target vegetables and objectively-assessed fruit and vegetable (FV) intake. METHODS: Seven hands-on, food-based STEAM learning activities were implemented to expose children to 9 target vegetables in 3 Head Start preschools (11 classrooms) across North Carolina. Child-reported vegetable liking scores and skin carotenoid status (SCS) were dependent variables collected at baseline, midpoint, and posttest. Adjusted repeated-measures ANOVA was used to examine intervention impact. RESULTS: A total of 113 children (intervention = 49; comparison = 64) participated. Children were an average age of 3.7 ± 0.57 years at baseline. Mean target vegetable liking scores for the intervention and comparison groups, respectively, were 3.2 ± 0.19 and 3.2 ± 0.17 at baseline, 2.9 ± 0.17 and 3.1 ± 0.15 at midpoint, and 2.8 ± 0.15 and 3.1 ± 0.13 at posttest. A time × group interaction was not significant for target vegetable liking scores. Mean SCS were 268.6 ± 13.24 and 270.9 ± 12.13 at baseline, 271.3 ± 12.50 and 275.6 ± 11.46 at midpoint, and 267.8 ± 11.26 and 229.6 ± 10.32 at posttest for the intervention and comparison groups, respectively. A time × group interaction was significant for SCS (F1,77 = 3.98; P = 0.02; r = 0.10). Both groups declined from baseline to posttest (intervention = 0.06%; comparison = 15.09%), which occurred after winter break, with a smaller decline observed in the intervention group (P = 0.02). CONCLUSIONS AND IMPLICATIONS: Food-based STEAM learning activities may present a unique opportunity to affect FV intake while meeting academic standards. More research is needed to understand how liking for familiar FV changes over time and its relationship with consumption. In addition, more implementation research featuring larger sample sizes, teachers as the interventionist, and a longer study duration is needed to confirm the outcomes of food-based STEAM learning observed in the current study and the long-term impact this approach may have on children's' dietary quality.


Subject(s)
Food Preferences , Vegetables , Carotenoids , Child, Preschool , Diet , Feeding Behavior , Fruit , Humans , Mathematics , Technology
14.
Adm Policy Ment Health ; 48(2): 343-353, 2021 03.
Article in English | MEDLINE | ID: mdl-32833167

ABSTRACT

Gatekeeper trainings have been increasingly utilized in response to rising suicide rates in youths. However, the extent to which common factors inherent to gatekeeper trainings impact training outcomes is largely understudied. As such, the present study explored how factors such as training size and trainer engagement abilities influenced trainee participation and outcomes (i.e. changes in attitudes, perceived behavioral control (PBC), and knowledge regarding suicide prevention). All trainees participated in a gatekeeper training; trainers were not randomly assigned. Mediation and moderation analyses were completed using the PROCESS macro for SPSS (Hayes in Introduction to mediation, moderation, and conditional process analysis: a regression-based approach, Guilford Press, New York, 2013). Trainee participation in a training was examined as a mediator of the relationship between the training size and training outcomes, while trainer engagement was examined as a moderator of the relationship between size of training and trainee participation. Size of training was significantly related to lower changes in participant knowledge, along with lower trainee participation in gatekeeper trainings. Trainee participation significantly mediated the relationship between size of training, attitudes, and PBC. Additionally, trainer engagement significantly moderated the association between size of training and trainee participation. The results of this study suggest that general gatekeeper training-related variables may influence participant outcomes, specifically through trainee participation.


Subject(s)
Suicide , Adolescent , Attitude , Humans , New York
15.
J Biomed Opt ; 25(3): 1-11, 2019 09.
Article in English | MEDLINE | ID: mdl-31489806

ABSTRACT

As solid-state laser technology continues to mature, high-energy lasers operating in the near-infrared (NIR) band have seen increased utilization in manufacturing, medical, and military applications. Formulations of maximum permissible exposure limits establish guidelines for the safe use of these systems for a given set of laser parameters, based on past experimental and analytical studies of exposure thresholds causing injury to the skin and eyes. The purpose of our study is to characterize the skin response to multiple-pulsed laser exposures at the NIR wavelength of 1070 nm, at a constant beam diameter of 1 cm, using anesthetized Yucatan mini-pig subjects. Our study explores three constant total laser-on times of 0.01, 0.1, and 10 s as single- and multiple-pulse sequences. Exposures consisting of 10, 30, and 100 pulses have identical individual pulse durations but different duty cycles in order to include variable degrees of thermal additivity. A plurality of three observers quantifies skin damage with the minimally visible lesion metric, judged at the 1- and 24-h intervals postexposure. Calculation of the median effective dose (ED50) provides injury thresholds for all exposure conditions, based on varying laser power across subjects. The results of this study will provide a quantitative basis for the incorporation of multiple-pulsed laser exposure into standards and augment data contained in the existing ED50 database.


Subject(s)
Lasers/adverse effects , Skin/injuries , Animals , Dose-Response Relationship, Radiation , Heat-Shock Response/radiation effects , Infrared Rays , Radiation Dosage , Swine , Swine, Miniature
16.
Psychiatry Res ; 275: 61-70, 2019 05.
Article in English | MEDLINE | ID: mdl-30878858

ABSTRACT

Although emotion regulation has been identified as a key function of non-suicidal self-injury (NSSI), it is unclear how specific indices of emotion regulation are associated with particular NSSI methods as markers of risk. This study used latent class analysis (LCA) to identify subgroups of individuals who engage in NSSI and their patterns of emotional regulation difficulties. Undergraduate students in the southeastern United States (N = 326) completed an online survey. LCA was used to identify subgroups of individuals engaging in NSSI and their associated emotion regulation difficulties. These subgroups were then compared across a variety of behavioral health outcomes (e.g. impulsive behavior, disordered eating, problematic alcohol use, suicide attempt history) to characterize specific risk profiles. The LCA revealed four subgroups who engage in NSSI and have specific emotion regulation difficulties. These subgroups were differentially associated with behavioral health outcomes, including suicide risk, disordered eating, and impulsive behavior. Results of this research could aid in clinical identification of at-risk individuals.


Subject(s)
Emotional Regulation , Emotions , Frustration , Latent Class Analysis , Self-Injurious Behavior/psychology , Suicide, Attempted/psychology , Adolescent , Emotional Regulation/physiology , Emotions/physiology , Feeding and Eating Disorders/diagnosis , Feeding and Eating Disorders/epidemiology , Feeding and Eating Disorders/psychology , Female , Humans , Impulsive Behavior/physiology , Male , Self-Injurious Behavior/diagnosis , Self-Injurious Behavior/epidemiology , Southeastern United States/epidemiology , Students/psychology , Surveys and Questionnaires
18.
Ecol Food Nutr ; 58(2): 166-186, 2019.
Article in English | MEDLINE | ID: mdl-30712385

ABSTRACT

This study examined the accuracy of parent-report child fruit/vegetable (FV) liking. Child/parent dyads (n = 24) were recruited from six Head Start preschools in North Carolina. Liking for 10 FVs was assessed using a validated pictorial tool for children; a similar scale was used for parents. Negative relationships were observed between parent/child for one fruit (grapes) and one vegetable (broccoli). Positive relationships were observed among oranges, grapes, and overall fruit rankings. Parents tended to rank children's liking of fruits higher than their children, while children ranked liking vegetables higher. Findings suggest parents may not be accurate respondents for preschool children's FV liking.


Subject(s)
Diet , Food Preferences , Parent-Child Relations , Parents , Proxy , Surveys and Questionnaires , Child , Child, Preschool , Female , Fruit , Humans , Male , Reproducibility of Results , Vegetables
19.
J Appl Physiol (1985) ; 126(2): 494-501, 2019 02 01.
Article in English | MEDLINE | ID: mdl-30571293

ABSTRACT

Of the 300 billion capillaries in the human lung, a small fraction meet normal oxygen requirements at rest, with the remainder forming a large reserve. The maximum oxygen demands of the acute stress response require that the reserve capillaries are rapidly recruited. To remain primed for emergencies, the normal cardiac output must be parceled throughout the capillary bed to maintain low opening pressures. The flow-distributing system requires complex switching. Because the pulmonary microcirculation contains contractile machinery, one hypothesis posits an active switching system. The opposing hypothesis is based on passive switching that requires no regulation. Both hypotheses were tested ex vivo in canine lung lobes. The lobes were perfused first with autologous blood, and capillary switching patterns were recorded by videomicroscopy. Next, the vasculature of the lobes was saline flushed, fixed by glutaraldehyde perfusion, flushed again, and then reperfused with the original, unfixed blood. Flow patterns through the same capillaries were recorded again. The 16-min-long videos were divided into 4-s increments. Each capillary segment was recorded as being perfused if at least one red blood cell crossed the entire segment. Otherwise it was recorded as unperfused. These binary measurements were made manually for each segment during every 4 s throughout the 16-min recordings of the fresh and fixed capillaries (>60,000 measurements). Unexpectedly, the switching patterns did not change after fixation. We conclude that the pulmonary capillaries can remain primed for emergencies without requiring regulation: no detectors, no feedback loops, and no effectors-a rare system in biology. NEW & NOTEWORTHY The fluctuating flow patterns of red blood cells within the pulmonary capillary networks have been assumed to be actively controlled within the pulmonary microcirculation. Here we show that the capillary flow switching patterns in the same network are the same whether the lungs are fresh or fixed. This unexpected observation can be successfully explained by a new model of pulmonary capillary flow based on chaos theory and fractal mathematics.


Subject(s)
Capillaries/physiology , Erythrocytes/physiology , Hemodynamics , Lung/blood supply , Microcirculation , Models, Cardiovascular , Pulmonary Circulation , Animals , Blood Flow Velocity , Dogs , Fractals , Male , Microscopy, Video , Models, Animal , Nonlinear Dynamics , Time Factors , Tissue Fixation
20.
J Biomed Opt ; 23(12): 1-11, 2018 12.
Article in English | MEDLINE | ID: mdl-30550049

ABSTRACT

Skin injury response to near-infrared (NIR) laser radiation between the minimum visible lesion threshold and ablation onset is not well understood. This study utilizes a 1070-nm diode-pumped Yb-fiber laser to explore the response of excised porcine skin to high-energy exposures in the suprathreshold injury region without inducing ablation. Concurrent high-speed videography is employed to determine a dichotomous response for three progressive damage categories: observable surface distortion, surface bubble formation due to contained intracutaneous water vaporization, and surface bubble rupture during exposure. Median effective dose (ED50) values are calculated in these categories for 3- and 100-ms pulses with beam diameters (1 / e2) of 3 mm (28, 35, and 49 J / cm2) and 7 mm (96, 141, and 212 J / cm2), respectively. Double-pulse cases are secondarily investigated. Experimental data are compared with the maximum permissible exposure limits and ablation onset simulated by a one-dimensional multiphysics model. Logistic regression analysis predicted injury events with ∼90 % of accuracy. The distinction of skin response into progressive damage categories expands the current understanding of high-energy laser safety while underlining the unique biophysical effects during induced water phase change in tissue. These results prove to be useful in the diagnosis and treatment of NIR laser injuries.


Subject(s)
Lasers/adverse effects , Radiation Injuries/pathology , Skin/pathology , Skin/radiation effects , Animals , Infrared Rays/adverse effects , Laser Therapy , Radiation Dosage , Radiation Injuries/diagnostic imaging , Skin/diagnostic imaging , Skin/injuries , Swine
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