scholarly journals In Vivo Documentation of Stimulus Velocity Tuning of Mechanically Induced Reflex Cough

2020 ◽  
pp. S139-S145
Author(s):  
B. Demoulin ◽  
L. Coutier-Marie ◽  
I. Ioan ◽  
C.E. Schweitzer ◽  
L. Foucauld ◽  
...  
Keyword(s):  
Rotational Velocity ◽  
Nonparametric Test ◽  
Mechanical Stimulus ◽  
Repeated Measurements ◽  
Stimulus Velocity ◽  
Cough Reflex ◽  
Dynamic Phase ◽  
Reflex Cough ◽  
Mechanical Probe

In order to clear airways and lungs defensive reflexes are provoked rather by the dynamic phase of mechanical stimulus. It is speculated that provocation of defensive response depends not only on stimulus duration but also on stimulus velocity. Fourteen adult rabbits were anaesthetized and tracheotomized. Mechanical stimulus was provoked by a mechanical probe introduced through the tracheotomy and rotated by a small electrical motor using a rotational velocity of 40 rpm/s and 20 rpm/s. Threshold, incidence and intensity of cough reflex (CR) were analyzed for each animal. Statistical comparisons between two velocities were performed using Friedman nonparametric test for repeated measurements. Results are median (25-75 %). The threshold of CR was significantly increased (p=0.005) from 350 ms (300-500 ms) to 550 ms (350-1150 ms) and the incidence of cough reflex was significantly reduced (p=0.002) from 50 % (19 50 %) to 0 % (0-25 %) when the rotational velocity of the mechanical probe was reduced by half. The findings of this study are of interest as they show that protective reflex cough, an important mechanism that allows clearing airways even during sleep or anesthesia, is tuned by mechanical stimulus velocity.

scholarly journals An initial exploration of in vivo hair cortisol responses to a brief pain stressor: latency, localization and independence effects

2009 ◽  
pp. 757-761
Author(s):  
CF Sharpley ◽  
KG Kauter ◽  
JR McFarlane
Keyword(s):  
Hpa Axis ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Hair Follicles ◽  
Repeated Measurements ◽  
Single Observation ◽  
Target Organs ◽  
Cortisol Responses

Cortisol is secreted by the central hypothalamo-pituitary-adrenal axis and affects many target organs and tissues, particularly in response to stressor demands and infection. Recent data reporting cortisol synthesis in hair follicles have shown the existence of a parallel “peripheral” HPA-axis. However, although there is evidence from in vitro studies and single-observation comparisons between groups that cortisol from hair follicles reflects endocrine changes associated with stressor demands, there are no reports to date of repeated measurements of in vivo cortisol responsivity in hair to transitory stressors. This issue was investigated with three males who underwent 1 min cold pressor test (CP). Cortisol response in hair to stressor demand appears to be (a) swift but transitory, (b) localized to the site of the demand and (c) independent of central HPA-axis activity.

Evaluation of an infrared laser-Doppler blood flowmeter

1987 ◽  
Vol 252 (6) ◽  
pp. G832-G839 ◽  
Author(s):  
A. P. Shepherd ◽  
G. L. Riedel ◽  
J. W. Kiel ◽  
D. J. Haumschild ◽  
L. C. Maxwell
Keyword(s):  
Rotational Velocity ◽  
Rotating Disk ◽  
Tissue Perfusion ◽  
Infrared Laser ◽  
Blood Oxygenation ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Flow Signal

Several laser-Doppler blood flowmeters are now commercially available; however, only one utilizes an infrared laser diode (Laserflo, TSI, St. Paul, MN). Because of this and other unique features such as its microprocessor-based signal analyzer, we evaluated this device's ability to measure tissue perfusion. Initially, we determined whether laser illumination directly affected the microvasculature. Intravital microscopic observations in the hamster cremaster muscle indicated that neither He-Ne nor infrared laser light affected the diameters of arterioles that were responsive to vasoactive agents. To test the flowmeter for linearity and repeatability, we used a rotating disk to simulate a light-scattering, flowing medium. The "flow" signal was highly correlated (r = 0.99) with the rotational velocity of the disk, was consistent among flow probes, and showed a high degree of reproducibility. The second model consisted of microsphere suspensions pumped through cuvettes. The laser-Doppler velocimeter (LDV) flow signal was linear with respect to pump output. With red blood cells in the perfusate, we examined the effects of blood oxygenation on the flowmeter's performance. The LDV flow signal was unaffected by changes in blood oxygenation. We evaluated linearity in vivo in isolated, perfused rat livers and in isolated canine gastric flaps. We observed linear relationships between total flow and laser-Doppler flow measured on the surface of the liver (r = 0.98) and in the gastric mucosa (r = 0.98), but the slopes of the relationships between total and local LDV flow showed considerable variability not noted in the in vitro studies.(ABSTRACT TRUNCATED AT 250 WORDS)

A multipurpose instrument for quantitative intravital microscopy

1992 ◽  
Vol 73 (1) ◽  
pp. 296-306 ◽  
Author(s):  
A. Toth ◽  
M. E. Tischler ◽  
M. Pal ◽  
A. Koller ◽  
P. C. Johnson
Keyword(s):  
Parenchymal Cell ◽  
Fluorescence Emission ◽  
Repeated Measurements ◽  
Open Architecture ◽  
In Vitro Tests ◽  
Fluorescence Measurements ◽  
Tissue Area ◽  
Microcirculatory Function

An in vivo microscope system has been developed that can measure fluorescence emission and/or light absorption at up to five wavelengths in a tissue area of 18–30 microns diam while imaging adjacent microcirculatory vessels with a video system. The system also incorporates a computer-controlled stage and data acquisition system for rapid and repeated measurements from a number of tissue sites. The tissue area monitored for fluorescence or absorption can be defined further by a confocal arrangement of the microscope optics. Tests of the system for NADH fluorescence measurements show good agreement between the fluorescence at 450 nm and NADH concentration in vitro and in skeletal muscle. The instrument can also be used simultaneously for spectrophotometric determination of O2 saturation and hematocrit in microcirculatory vessels. In vitro tests indicate suitable accuracy for such measurements. The open architecture and modular arrangement of the instrument facilitates its use for a variety of simultaneous measurements of parenchymal cell and microcirculatory function.

Aortic perfusion pressure as early determinant of beta-isomyosin expression in perfused hearts

1992 ◽  
Vol 263 (5) ◽  
pp. H1537-H1545
Author(s):  
C. Delcayre ◽  
D. Klug ◽  
V. T. Nguyen ◽  
C. Mouas ◽  
B. Swynghedauw
Keyword(s):  
Protein Synthesis ◽  
Total Protein ◽  
Stress Protein ◽  
Pressure Overload ◽  
Aortic Pressure ◽  
Mechanical Stimulus ◽  
Beating Heart ◽  
Specific Gene ◽  
Coronary Pressure

Pressure overload in vivo induces an increase in cardiac protooncogene and stress protein expression that may initiate the long-term genetic changes observed in hypertrophy. To known whether mechanical stimulus is linked to specific gene transcription, expression of immediate early genes and synthesis of total proteins and myosin heavy chains (MHCs) were studied in beating and KCl-arrested isolated rat hearts perfused for 2 h under various coronary pressures. The main result of this study is that in the beating heart an augmentation of aortic pressure from 60 to 120 mmHg results in a pronounced enhancement of the synthesis of MHC (+59%) and of the expression of the beta-MHC isomyosin mRNA (iso-mRNA; +104%). Also, total protein synthesis and the amounts of poly-(A)+, c-fos, c-myc, and heat-shock protein HSP68 mRNAs were increased. To arrest the heart at 60 mmHg has no effect on total protein synthesis and on the amounts of poly(A)+, alpha-MHC and beta-MHC iso-mRNAs, and mRNAs coding for oncoproteins, but the synthesis of MHC decreased by 24%. By contrast with what we have observed in the beating heart, the augmentation of the coronary pressure in the arrested heart stimulates total protein synthesis and increases the amount of poly(A)+, c-fos, c-myc, and HSP68 mRNAs but has no effect on the expression of both MHC iso-mRNAs. In conclusion, the activation of myosin synthesis by high coronary pressure in this model has mainly a pretranslational origin when the heart is beating.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Mapping Short Association Fibers in the Early Cortical Visual Processing Stream Using In Vivo Diffusion Tractography

2020 ◽  
Vol 30 (8) ◽  
pp. 4496-4514 ◽  
Author(s):  
Fakhereh Movahedian Attar ◽  
Evgeniya Kirilina ◽  
Daniel Haenelt ◽  
Kerrin J Pine ◽  
Robert Trampel ◽  
...  
Keyword(s):  
Human Brain ◽  
Visual Processing ◽  
Repeated Measurements ◽  
Fiber Tractography ◽  
Cortical Areas ◽  
Brain Connectome ◽  
Cortical Visual Processing ◽  
Association Fibers ◽  
Fiber Connectivity

Abstract Short association fibers (U-fibers) connect proximal cortical areas and constitute the majority of white matter connections in the human brain. U-fibers play an important role in brain development, function, and pathology but are underrepresented in current descriptions of the human brain connectome, primarily due to methodological challenges in diffusion magnetic resonance imaging (dMRI) of these fibers. High spatial resolution and dedicated fiber and tractography models are required to reliably map the U-fibers. Moreover, limited quantitative knowledge of their geometry and distribution makes validation of U-fiber tractography challenging. Submillimeter resolution diffusion MRI—facilitated by a cutting-edge MRI scanner with 300 mT/m maximum gradient amplitude—was used to map U-fiber connectivity between primary and secondary visual cortical areas (V1 and V2, respectively) in vivo. V1 and V2 retinotopic maps were obtained using functional MRI at 7T. The mapped V1–V2 connectivity was retinotopically organized, demonstrating higher connectivity for retinotopically corresponding areas in V1 and V2 as expected. The results were highly reproducible, as demonstrated by repeated measurements in the same participants and by an independent replication group study. This study demonstrates a robust U-fiber connectivity mapping in vivo and is an important step toward construction of a more complete human brain connectome.

scholarly journals Repeated measurements of tibia lead concentrations by in vivo x ray fluorescence in occupational exposure.

1992 ◽  
Vol 49 (1) ◽  
pp. 14-16
Author(s):  
R Armstrong ◽  
D R Chettle ◽  
M C Scott ◽  
L J Somervaille ◽  
M Pendlington
Keyword(s):  
Occupational Exposure ◽  
Repeated Measurements ◽  
X Ray

Concurrent Estimation of Total Body and Exchangeable Body Sodium in Hypertension

1978 ◽  
Vol 54 (2) ◽  
pp. 187-191 ◽  
Author(s):  
K. Boddy ◽  
J. J. Brown ◽  
D. L. Davies ◽  
A. Elliott ◽  
I. Harvey ◽  
...  
Keyword(s):  
Activation Analysis ◽  
Repeated Measurements ◽  
Exchangeable Sodium ◽  
Additional Tool ◽  
Body Sodium ◽  
Calcium Phosphorus ◽  
Sodium Metabolism ◽  
Total Body ◽  
Concurrent Estimation

1. Total-body neutron-activation analysis in vivo was carried out in 11 hypertensive subjects to measure simultaneously the total body content of sodium, chlorine, calcium, phosphorus and nitrogen. 2. There was a highly significant correlation between total body sodium measured by activation analysis and total exchangeable sodium measured by a standard isotope-dilution technique (r = 0·92, P < 0·001). Exchangeable sodium averaged 80·3% of total body sodium. 3. The measured values of chlorine, calcium, phosphorus and nitrogen were similar to those for healthy subjects reported by others. 4. Activation analysis in vivo appears promising as an additional tool for investigating sodium metabolism in hypertension, as it is the only method available for determining the total body content of this element. The radiation dose (1 rem) is sufficiently low to permit repeated measurements in the same subject.

scholarly journals Clonal reconstruction from co-occurrence of vector integration sites allows accurate quantification of expanding clones in vivo

2021 ◽  
Author(s):  
Sebastian Wagner ◽  
Christoph Baldow ◽  
Andrea Calabria ◽  
Laura Rudilosso ◽  
Pierangela Gallina ◽  
...  
Keyword(s):  
Viral Vectors ◽  
R Package ◽  
Repeated Measurements ◽  
Preclinical Model ◽  
Gene Therapies ◽  
Vector Integration ◽  
Reconstruction Methods ◽  
Integration Sites ◽  
Safety Considerations

High transduction rates of viral vectors in gene therapies (GT) and experimental hematopoiesis ensure a high frequency of gene delivery, although multiple integration events can occur in the same cell. Therefore, tracing of integration sites (IS) leads to mis-quantification of the true clonal spectrum and limits safety considerations in GT. Hence, we use correlations between repeated measurements of IS abundances to estimate their mutual similarity and identify clusters of co-occurring IS, for which we assume a clonal origin. We evaluate the performance, robustness and specificity of our methodology using clonal simulations. The reconstruction methods, implemented and provided as an R-package, are further applied to experimental clonal mixes and to a preclinical model of hematopoietic GT. Our results demonstrate that clonal reconstruction from IS data allows to overcome systematic biases in the clonal quantification as an essential prerequisite for the assessment of safety and long-term efficacy of GT involving integrative vectors.

scholarly journals 165. Mycobacterium tuberculosis Produces Molecules That Trigger Nociceptive Neurons to Activate Cough

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S16-S16
Author(s):  
Cody Ruhl ◽  
Lexy Kindt ◽  
Haaris Khan ◽  
Chelsea E Stamm ◽  
Breanna Pasko ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Guinea Pig ◽  
Disease Transmission ◽  
Guinea Pigs ◽  
Neuronal Response ◽  
Cough Reflex ◽  
Nociceptive Neurons ◽  
Active Pulmonary Tuberculosis

Abstract Background A hallmark symptom of active pulmonary tuberculosis vital for disease transmission is cough. The current paradigm for tuberculosis-related cough is that it results from airway damage or irritation. However, there is limited experimental data to support this theory, and whether Mycobacterium tuberculosis (Mtb) induces cough to facilitate its own transmission has not been explored. The cough reflex is a complex and coordinated event involving both the nervous and musculoskeletal systems initiated by particulate or chemical molecules activating nociceptive neurons, which sense pain or irritation. This activation induces a signaling cascade ultimately resulting in a cough. Respiratory nociceptive neurons innervate the airway of humans and most mammals, and thus are poised to respond to noxious molecules to help protect the lung from damage. Because Mtb is a lung pathogen, cough is a primary mechanism of Mtb transmission, and respiratory nociceptive neurons activate cough, we hypothesized that Mtb produces molecules that stimulate cough, thereby facilitating its spread from infected to uninfected individuals. Methods We used an in vitro neuronal activation bioassay to fractionate, identify, and characterize Mtb cough-inducing molecules. We also measured cough in vivo in response to pure Mtb-derived cough molecules and during Mtb infection using a guinea pig model. Results We found that an acellular organic extract of Mtb triggers and activates nociceptive neurons in vitro with a neuronal response that is as robust as the response to capsaicin, an established nociceptive and cough-inducing molecule. Using analytical chemistry and our neuronal bioassay, we then isolated 2 molecules produced by Mtb that activate nociceptive neurons. Both the organic Mtb extract and purified molecules alone were sufficient to induce cough in a conscious guinea pig cough model. Finally guinea pigs infected with wild-type Mtb cough much more frequently than guinea pigs infected with Mtb strains unable to produce nociceptive molecules. Conclusion We conclude that Mtb produces molecules that activate nociceptive neurons and induce cough. These findings have significant implications for our understanding of Mtb transmission. Disclosures All authors: No reported disclosures.

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