scholarly journals Mapping O2 concentration in ex-vivo tissue samples on a fast PLIM macro-imager

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rajannya Sen ◽  
Alexander V. Zhdanov ◽  
Thomaz F. S. Bastiaanssen ◽  
Liisa M. Hirvonen ◽  
Peter Svihra ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Metabolic Imaging ◽  
Tissue Respiration ◽  
Tissue Samples ◽  
O2 Concentration ◽  
Tissue Surface ◽  
Acquisition Speed ◽  
Colonic Lumen ◽  
The Difference ◽  
Speed Accuracy

Abstract O2 PLIM microscopy was employed in various studies, however current platforms have limitations in sensitivity, image acquisition speed, accuracy and general usability. We describe a new PLIM imager based on the Timepix3 camera (Tpx3cam) and its application for imaging of O2 concentration in various tissue samples stained with a nanoparticle based probe, NanO2-IR. Upon passive staining of mouse brain, lung or intestinal tissue surface with minute quantities of NanO2-IR or by microinjecting the probe into the lumen of small or large intestine fragments, robust phosphorescence intensity and lifetime signals were produced, which allow mapping of O2 in the tissue within 20 s. Inhibition of tissue respiration or limitation of O2 diffusion to tissue produced the anticipated increases or decreases in O2 levels, respectively. The difference in O2 concentration between the colonic lumen and air-exposed serosal surface was around 140 µM. Furthermore, subcutaneous injection of 5 µg of the probe in intact organs (a paw or tail of sacrificed mice) enabled efficient O2 imaging at tissue depths of up to 0.5 mm. Overall, the PLIM imager holds promise for metabolic imaging studies with various ex vivo models of animal tissue, and also for use in live animals.

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller
Keyword(s):  
Ex Vivo ◽  
Moisture Loss ◽  
Speaking Valve ◽  
Time Zero ◽  
In Series ◽  
Turbulent Airflow ◽  
The Difference ◽  
Loss Efficiency ◽  
Heat And Moisture ◽  
Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

Abstract P211: Single High Na + Ingestion Leads To An Increase In Oxidative Stress And Triggers Inflammation.

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Ginette Bordcoch ◽  
Ivan Tavera Busso ◽  
Juan Masjoan Juncos ◽  
Luis I Juncos
Keyword(s):  
Oxidative Stress ◽  
The United States ◽  
Male Rats ◽  
Control Group ◽  
Aortic Tissue ◽  
Tissue Samples ◽  
Extracellular Signal ◽  
High Prevalence ◽  
Markers Of Oxidative Stress ◽  
The Difference

Hypertension has been linked to a progressive increased in oxidative stress and inflammation. The high prevalence of hypertension poses a great risk to public health as 108 million adults in the United States have the condition. For that reason, a better understanding of the link between a high Na+ intake and the development of hypertension is of crucial importance. We hypothesize that a single ingestion of a high Na+ solution leads to increased oxidative stress and triggers an inflammatory response. Wistar 200-250 g male rats had gastric infusions through the esophagus. Groups were infused with 8 mL liquid Vaseline (Control), 8 mL of NaCl 0.684 M (4% m/v), and 8 mL of NaCl 1.368 M (8% m/v). After infusion, blood was collected at different time points during the first hour. Tissue samples were obtained from the aorta, heart, and kidney. Electron Microscopy (EM) was performed on all tissues, which were also analyzed for molecular markers of oxidative stress: Superoxide Dismutase (SOD) and Malondialdehyde (MDA), and an inflammation marker: Extracellular Signal-Regulated Kinase (ERK). At 2 and a half minutes, serum Na+ concentration was unchanged in the control group compared to an increase observed in animals receiving 4% and 8% Na+ with concentrations of 135±1.4 mEq/L, 141±2.0 mEq/L, and 140±1.2 mEq/L respectively. At the 1-hour time point after infusion, the difference was further increased in the 8% group with serum concentrations of 135±1.8 mEq/L, 140±1.5 mEq/L, and 152±1mEq/L respectively (p<0.05). There was an increase in oxidative stress in the aorta from values of 36.22±4.64 mU/mg SOD and 0.131±0.013 pg/mL MDA in the control group, to 47.11±4.89 mU/mg SOD and 0.291±0.022 pg/mL MDA in the 8% group (p<0.05 in both cases). The same was observed in the heart, where values were: 174.6125.26 mU/mg SOD, 0.026±0.007 pg/mL MDA in controls, and 259.22±21.98 mU/mg SOD, 0.215±0.073 pg/mL MDA in 8% group (p<0.05 both cases). Increased ERK in aortic tissue, values of 0.29±0.03 pg/mL in controls, 2.68±0.18 pg/mL in 4% group and 3.97±0.68pg/mL in 8% group (p<0.05) suggest increased inflammation. We conclude that the elevation in serum Na+ concentration that follows Na+ ingestion leads to increased oxidative stress and inflammation.

scholarly journals SPS-neutralization in tissue samples for efficacy testing of antimicrobial peptides

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Gabrielle Sherella Dijksteel ◽  
Peter H. Nibbering ◽  
Magda M. W. Ulrich ◽  
Esther Middelkoop ◽  
Bouke K. H. L. Boekema
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Antimicrobial Agents ◽  
Ex Vivo ◽  
Residual Activity ◽  
Gram Negative Bacteria ◽  
Tissue Samples ◽  
Gram Negative ◽  
Viable Bacteria

Abstract Background Accurate determination of the efficacy of antimicrobial agents requires neutralization of residual antimicrobial activity in the samples before microbiological assessment of the number of surviving bacteria. Sodium polyanethol sulfonate (SPS) is a known neutralizer for the antimicrobial activity of aminoglycosides and polymyxins. In this study, we evaluated the ability of SPS to neutralize residual antimicrobial activity of antimicrobial peptides [SAAP-148 and pexiganan; 1% (wt/v) in PBS], antibiotics [mupirocin (Bactroban) and fusidic acid (Fucidin) in ointments; 2% (wt/wt))] and disinfectants [2% (wt/wt) silver sulfadiazine cream (SSD) and 0.5% (v/v) chlorhexidine in 70% alcohol]. Methods Homogenates of human skin models that had been exposed to various antimicrobial agents for 1 h were pipetted on top of Methicillin-resistant Staphylococcus aureus (MRSA) on agar plates to determine whether the antimicrobial agents display residual activity. To determine the optimal concentration of SPS for neutralization, antimicrobial agents were mixed with PBS or increasing doses of SPS in PBS (0.05–1% wt/v) and then 105 colony forming units (CFU)/mL MRSA were added. After 30 min incubation, the number of viable bacteria was assessed. Next, the in vitro efficacy of SAAP-148 against various gram-positive and gram-negative bacteria was determined using PBS or 0.05% (wt/v) SPS immediately after 30 min incubation of the mixture. Additionally, ex vivo excision wound models were inoculated with 105 CFU MRSA for 1 h and exposed to SAAP-148, pexiganan, chlorhexidine or PBS for 1 h. Subsequently, samples were homogenized in PBS or 0.05% (wt/v) SPS and the number of viable bacteria was assessed. Results All tested antimicrobials displayed residual activity in tissue samples, resulting in a lower recovery of surviving bacteria on agar. SPS concentrations at ≥0.05% (wt/v) were able to neutralize the antimicrobial activity of SAAP-148, pexiganan and chlorhexidine, but not of SSD, Bactroban and Fucidin. Finally, SPS-neutralization in in vitro and ex vivo efficacy tests of SAAP-148, pexiganan and chlorhexidine against gram-positive and gram-negative bacteria resulted in significantly higher numbers of CFU compared to control samples without SPS-neutralization. Conclusions SPS was successfully used to neutralize residual activity of SAAP-148, pexiganan and chlorhexidine and this prevented an overestimation of their efficacy.

scholarly journals Vitamin D alleviates oxidative stress in adipose tissue and mesenteric vessels from obese patients with subclinical inflammation

2020 ◽  
Vol 98 (2) ◽  
pp. 85-92 ◽  
Author(s):  
Mihaela Ionica ◽  
Oana M. Aburel ◽  
Adrian Vaduva ◽  
Alexandra Petrus ◽  
Sonia Rațiu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Vitamin D ◽  
Adipose Tissue ◽  
Vascular Function ◽  
Ex Vivo ◽  
Active Form ◽  
Reactive Oxygen Species Generation ◽  
Obese Patients ◽  
Tissue Samples

Obesity is an age-independent, lifestyle-triggered, pandemic disease associated with both endothelial and visceral adipose tissue (VAT) dysfunction leading to cardiometabolic complications mediated via increased oxidative stress and persistent chronic inflammation. The purpose of the present study was to assess the oxidative stress in VAT and vascular samples and the effect of in vitro administration of vitamin D. VAT and mesenteric artery branches were harvested during abdominal surgery performed on patients referred for general surgery (n = 30) that were randomized into two subgroups: nonobese and obese. Serum levels of C-reactive protein (CRP) and vitamin D were measured. Tissue samples were treated or not with the active form of vitamin D: 1,25(OH)2D3 (100 nmol/L, 12 h). The main findings are that in obese patients, (i) a low vitamin D status was associated with increased inflammatory markers and reactive oxygen species generation in VAT and vascular samples and (ii) in vitro incubation with vitamin D alleviated oxidative stress in VAT and vascular preparations and also improved the vascular function. We report here that the serum level of vitamin D is inversely correlated with the magnitude of oxidative stress in the adipose tissue. Ex vivo treatment with active vitamin D mitigated obesity-related oxidative stress.

scholarly journals Endothelin receptor antagonist improves donor lung function in an ex vivo perfusion system

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
K. Walweel ◽  
K. Skeggs ◽  
A. C. Boon ◽  
L. E. See Hoe ◽  
M. Bouquet ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Partial Pressure ◽  
Ex Vivo ◽  
Weight Ratio ◽  
Dry Weight ◽  
Lung Damage ◽  
Endothelin Receptor ◽  
Donor Pool ◽  
Ex Vivo Lung Perfusion ◽  
Tissue Samples

Abstract Background A lung transplant is the last resort treatment for many patients with advanced lung disease. The majority of donated lungs come from donors following brain death (BD). The endothelin axis is upregulated in the blood and lung of the donor after BD resulting in systemic inflammation, lung damage and poor lung graft outcomes in the recipient. Tezosentan (endothelin receptor blocker) improves the pulmonary haemodynamic profile; however, it induces adverse effects on other organs at high doses. Application of ex vivo lung perfusion (EVLP) allows the development of organ-specific hormone resuscitation, to maximise and optimise the donor pool. Therefore, we investigate whether the combination of EVLP and tezosentan administration could improve the quality of donor lungs in a clinically relevant 6-h ovine model of brain stem death (BSD). Methods After 6 h of BSD, lungs obtained from 12 sheep were divided into two groups, control and tezosentan-treated group, and cannulated for EVLP. The lungs were monitored for 6 h and lung perfusate and tissue samples were processed and analysed. Blood gas variables were measured in perfusate samples as well as total proteins and pro-inflammatory biomarkers, IL-6 and IL-8. Lung tissues were collected at the end of EVLP experiments for histology analysis and wet-dry weight ratio (a measure of oedema). Results Our results showed a significant improvement in gas exchange [elevated partial pressure of oxygen (P = 0.02) and reduced partial pressure of carbon dioxide (P = 0.03)] in tezosentan-treated lungs compared to controls. However, the lungs hematoxylin–eosin staining histology results showed minimum lung injuries and there was no difference between both control and tezosentan-treated lungs. Similarly, IL-6 and IL-8 levels in lung perfusate showed no difference between control and tezosentan-treated lungs throughout the EVLP. Histological and tissue analysis showed a non-significant reduction in wet/dry weight ratio in tezosentan-treated lung tissues (P = 0.09) when compared to control. Conclusions These data indicate that administration of tezosentan could improve pulmonary gas exchange during EVLP.

scholarly journals Effect of glucose on 7-hydroxycoumarin glucuronide production in periportal and pericentral regions of the liver lobule

1985 ◽  
Vol 226 (3) ◽  
pp. 749-756 ◽  
Author(s):  
J G Conway ◽  
F C Kauffman ◽  
R G Thurman
Keyword(s):  
Glucuronic Acid ◽  
Half Time ◽  
Rapid Synthesis ◽  
Fluorescence Excitation ◽  
Glucose Addition ◽  
Liver Lobule ◽  
Tissue Surface ◽  
The Difference ◽  
Light Guides ◽  
Effect Of Glucose

The effect of starvation and glucose addition on glucuronidation was assessed in sublobular regions of the lobule in perfused livers from phenobarbital-treated rats. Fibre-optic micro-light guides were placed on periportal and pericentral areas on the surface of livers to monitor the fluorescence (excitation 366 nm, emission 450 nm) of free 7-hydroxycoumarin from the tissue surface. After infusion of 7-hydroxycoumarin (80 microM) under normoxic conditions, steady-state increases in fluorescence were reached in 6-8 min in both regions. Subsequently, the formation of non-fluorescent 7-hydroxycoumarin glucuronide was inhibited completely by perfusion with N2-saturated perfusate containing 20 mM-ethanol. The difference in fluorescence between anoxic and normoxic perfusions was due to glucuronidation under these conditions. In livers from fed rats, rates of glucuronidation in periportal and pericentral regions of the liver lobule were 8 and 19 mumol/h per g, respectively. In contrast, rates of glucuronidation were 3 and 9 mumol/h per g, respectively, in periportal and pericentral regions of livers from starved rats. Infusion of glucose (20 mM) had no effect on rates of glucuronidation in livers from fed rats; however, glucose increased rates of glucuronidation rapidly (half-time, t0.5 = 1.5 min) in periportal and pericentral regions to 7 and 17 mumol/h per g, respectively in livers from starved rats. These results indicate that the rapid synthesis of the cofactor UDP-glucuronic acid derived from glucose is an important rate-determinant for glucuronidation of 7-hydroxycoumarin in both periportal and pericentral regions of livers from starved rats.

Transcapillary Starling forces using membrane osmometry

1980 ◽  
Vol 238 (6) ◽  
pp. H886-H888
Author(s):  
J. L. Christian ◽  
R. A. Brace
Keyword(s):  
Osmotic Pressure ◽  
Interstitial Fluid ◽  
Subcutaneous Tissue ◽  
Fluid Pressure ◽  
Colloid Osmotic Pressure ◽  
Interstitial Fluid Pressure ◽  
Tissue Samples ◽  
Small Pore ◽  
The Difference ◽  
Good Agreement

Membrane osmometry was used to estimate the four transcapillary Starling pressures in subcutaneous tissue of rats, guinea pigs, and dogs. Isolated subcutaneous tissue samples were either placed on a large-pore or small-pore osmometer that measured the interstitial fluid pressure (Pif) and the difference between the interstitial fluid pressure and the interstitial protein osmotic pressure (Pif-pi if), respectively. The colloid osmotic pressure of the interstitial fluid (pi if) was obtained from the difference in these two pressures. A plasma sample placed on the small-pore osmometer yielded the colloid osmotic pressure of the plasma proteins (pi c). Finally the capillary pressure (Pc) was calculated from the three other Starling forces. In the rat, guinea pig, and dog, respectively, the estimated Starling forces were as follows: Pif -2.2, -2.1, and -4.8 mmHg; pi if, 7.3, 4.8, and 4.4 mmHg; pi c, 21.3, 19.5, and 19.2 mmHg; and Pc, 11.8, 12.6, and 10.0 mmHg. A comparison with data obtained in other studies using different methods shows good agreement and strongly supports membrane osmometry as a method for measuring the Starling pressures in subcutaneous tissue.

Opening plugged tympanostomy tubes: Effect of inner diameter and shaft length

2005 ◽  
Vol 132 (2) ◽  
pp. 322-326 ◽  
Author(s):  
Ajay J. Mehta ◽  
Gary R. Stevens ◽  
Patrick J. Antonelli
Keyword(s):  
Study Design ◽  
Middle Ear ◽  
Ex Vivo ◽  
Tympanostomy Tube ◽  
Ex Vivo Model ◽  
Shaft Length ◽  
Tympanostomy Tubes ◽  
Inner Diameter ◽  
The Difference

OBJECTIVE: To determine whether tympanostomy tube (TT) inner diameter or shaft length impacts the rate of mucoid plug clearance. STUDY DESIGN AND SETTING: Ex vivo model. Silicone TTs with different inner-diameters (ID) and shaft-length (SL) pairings (1.14 mm ID × 12 mm SL versus 1.14 mm ID × 1 mm SL; 1.14 mm ID × 4.8 mm SL versus 1.32 mm ID × 4.8 mm SL) were plugged with middle-ear mucus (n = 15 per group) and placed in a model ear chamber. Ofloxacin otic solution was instilled into the chamber to cover the plugged TT, and the time to clearance of each plug was recorded. RESULTS: TTs with larger IDs ( P = 0.019) and greater SLs ( P = 0.033) cleared plugs more rapidly. However, the difference in the percentage of tubes that unplugged was not significant ( P = 0.151). CONCLUSIONS: Rate of ex vivo TT plug clearance may be altered by changing TT ID and SL.

Tissue Models of Peritoneal Fibrosis

2005 ◽  
Vol 28 (2) ◽  
pp. 105-111 ◽  
Author(s):  
J.A. Jiménez-Heffernan ◽  
A. Cirugeda ◽  
M.A. Bajo ◽  
G. Del Peso ◽  
M.L. Pérez-Lozano ◽  
...  
Keyword(s):  
Acute Inflammation ◽  
Epithelial To Mesenchymal Transition ◽  
Ex Vivo ◽  
Peritoneal Fibrosis ◽  
Tissue Samples ◽  
Mesenchymal Transition ◽  
Cellular Markers ◽  
Tissue Models ◽  
Myofibroblastic Differentiation

Objective To evaluate the utility of peritoneal pathologic samples, unrelated to peritoneal dialysis (PD) treatment, for the study of peritoneal fibrosis and inflammation. Methods Comparative morphologic and immunohistochemical study of peritoneal pathologic samples unrelated to PD with peritoneal biopsies from PD patients with special emphasis on the expression of myofibroblastic and epithelial-to-mesenchymal transition markers. Results Regarding morphology, PD-related simple fibrosis was less cellular, with greater stromal hyalinization, determining a homogeneous, hypocellular aspect of the submesothelium. In contrast, non-PD fibrosis was more cellular with an extracellular matrix showing a dense and fibrillar quality with wide bundles of collagen. Hylinazing vasculopathy was only present in PD samples. Myofibroblastic differentiation and epithelial-to-mesenchymal transition were common findings in all situations of peritoneal fibrosis. Calponin and calretinin are useful cellular markers to study such fibrogenic mechanisms and correlate with other well-known markers such as α-SMA and cytokeratins. Their expression was much more intense in those samples showing acute inflammation (peritonitis). Conclusions Non-PD models of peritoneal fibrosis seem very useful to evaluate important features of human peritoneal pathology such us fibrogenesis, and inflammation. Fibrogenic events such as myofibroblastic differentiation and epithelial-to-mesenchymal transition are evident in these tissue samples allowing us to use them as an accessible source for in vivo and ex vivo studies. Both events show their maximal expression in situations of acute inflammation supporting the important role that peritonitis episodes play in the progression of fibrosis.

Evaluation of bone mineral density through radiographic optical densitometry in 42 canine femures

2021 ◽  
Vol XXVI (150) ◽  
pp. 64-69
Author(s):  
Bianca Marfil Dias ◽  
Anderson F. de Souza ◽  
André Luis do V. De Zoppa
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Ex Vivo ◽  
Mineral Density ◽  
Trend Function ◽  
Tissue Samples ◽  
Area Of Interest ◽  
Atypical Values ◽  
Biomechanical Tests ◽  
Densitometric Data

This study evaluates the bone mineral density of 42 canine femurs using radiographic optical densitometry and validates radiographic optical densitometry as a parameter to standardize bone tissue samples used in biomechanical tests, contributing to the diagnosis of osteoporosis in dogs. The ImageJ 1.46r® program was used for the radiographic optical densitometry. After selecting the aluminum steps and the area of interest in the femur, the data obtained were stored in a table and converted into mm/Al using the MS Excel® trend function. Statistical analysis demonstrated the absence of atypical values (outiliers) in the samples analyzed. The samples evaluated were homogeneous and the densitometric data obtained may contribute to reducing the scarcity of densitometric references in the veterinary literature. Ex vivo biomechanical studies may benefit from the method used in this study to standardize their sample when evaluating bone mineral density, validating their respective projects

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