scholarly journals The effect of gas exchange on multiple-breath nitrogen washout measures of ventilation inhomogeneity in the mouse

2014 ◽  
Vol 117 (9) ◽  
pp. 1049-1054 ◽  
Author(s):  
Mahesh Dharmakumara ◽  
G. Kim Prisk ◽  
Simon G. Royce ◽  
Merryn Tawhai ◽  
Bruce R. Thompson
Keyword(s):  
Gas Exchange ◽  
Continuous Process ◽  
Small Animal ◽  
Mouse Lung ◽  
Small Animals ◽  
Nitrogen Washout ◽  
Ventilation Inhomogeneity ◽  
Lung Clearance Index ◽  
Per Se ◽  
Gas Volume

Inert-gas washout measurements using oxygen, in the lungs of small animals, are complicated by the continuous process of oxygen consumption (V̇o2). The multiple-breath nitrogen washout (MBNW) technique uses the alveolar slope to determine measures of ventilation inhomogeneity in the acinar ( Sacin) and conducting ( Scond) airway regions, as well as overall inhomogeneity, as determined by the lung clearance index (LCI). We hypothesized that measured ventilation inhomogeneity in the mouse lung while it is alive is in fact an artifact due to the high V̇o2 in proportion to alveolar gas volume (Va), and not ventilation inhomogeneity per se. In seven male C57BL/6 mice, MBNW was performed alive and postmortem to derive measures with and without the effect of gas exchange, respectively. These results were compared with those obtained from an asymmetric multibranch point mathematical model of the mouse lung. There was no statistical difference in Sacin and LCI between alive and postmortem results ( Sacin alive = 0.311 ± 0.043 ml−1 and Sacin postmortem = 0.338 ± 0.032 ml−1, LCI alive = 7.0 ± 0.1 and LCI postmortem = 7.0 ± 0.1). However, there was a significant decrease in Scond from 0.086 ± 0.005 ml−1 alive to 0.006 ± 0.002 ml−1 postmortem ( P < 0 .01). Model simulations replicated these results. Furthermore, in the model, as V̇o2 increased, so did the alveolar slope. These findings suggests that the MBNW measurement of Scond in the mouse lung is confounded by the effect of gas exchange, a result of the high V̇o2-to-Va ratio in this small animal, and not due to inhomogeneity within the airways.

Recommendations for Intensive Care Management in Small Animals Following Anaesthesia

1992 ◽  
Vol 05 (02) ◽  
pp. 66-70
Author(s):  
Karol Mathews ◽  
Doris Dyson
Keyword(s):  
Intensive Care ◽  
Care Management ◽  
Small Animal ◽  
Small Animals ◽  
Monitoring Equipment ◽  
Intensive Care Management ◽  
Good Communication

Intensive care management can be provided in a small animal facility by centralisation of emergency and monitoring equipment. Good communication between all personnel involved in the case ensures that staff are prepared for complications that could arise related to recovery from anaesthesia.

EMPTY BODY WEIGHTS, CARCASS WEIGHTS AND OFFAL PROPORTIONS IN BULLS AND STEERS OF DIFFERENT MATURE SIZE

1984 ◽  
Vol 64 (1) ◽  
pp. 53-57 ◽  
Author(s):  
S. D. M. JONES ◽  
R. E. ROMPALA ◽  
J. W. WILTON ◽  
C. H. WATSON
Keyword(s):  
Body Weight ◽  
Small Animal ◽  
High Energy ◽  
Carcass Weight ◽  
Small Animals ◽  
Beef Steers ◽  
Body Weights ◽  
Breed Crosses ◽  
Large Animals ◽  
Animal Size

Empty body weights, carcass weights and offal proportions were compared in 33 young beef bulls and 33 beef steers of different mature body size (35 small or mainly British breed crosses, 31 large or Continental crosses). All cattle were fed a high energy diet based on corn silage and high moisture corn from weaning to slaughter. Slaughter was carried out once 6 mm of fat had been attained at the 11/12th ribs, determined ultrasonically. Feed was removed 24 h and water 16 h prior to slaughter. The offal components were all weighed fresh and the alimentary components emptied of digesta. Bulls weighed 8.0% heavier (P < 0.05) than steers at slaughter, while large animals were 38.7% heavier (P < 0.0001) than small animals. Bulls and large animals had carcasses that dressed out 1.5% heavier than steers and small animals. To eliminate the effect of gutfill, carcass weights and offal components were expressed as a proportion of empty body weight. Bulls had a higher proportion of warm carcass weight and lower proportions of liver, spleen, heart, lungs, rumen, abomasum, large intestine and front feet relative to empty body weight than steers. Large animals had a greater proportion of warm carcass weight and hind feet, and a lower proportion of head, hide, liver, kidneys, omasum and small intestine relative to empty body weight than small animals. All castration by size interactions for liveweight, carcass weight, empty body weight and offal proportions were not significant. Castration and small animal size both increased the proportion of noncarcass parts relative to empty body weight in animals slaughtered at similar finish. Key words: Body, carcass, offal, bull, steer, maturity

Use of the Leksell Gamma Knife for Localized Small Field Lens Irradiation in Rodents

2003 ◽  
Vol 2 (5) ◽  
pp. 449-454 ◽  
Author(s):  
Colleen DesRosiers ◽  
Marc S. Mendonca ◽  
Craig Tyree ◽  
Vadim Moskvin ◽  
Morris Bank ◽  
...  
Keyword(s):  
Gamma Knife ◽  
High Precision ◽  
Small Animal ◽  
Small Animals ◽  
Small Field ◽  
Thermoluminescent Dosimeters ◽  
Ion Chamber ◽  
Order Of Magnitude ◽  
Contralateral Eye

For most basic radiobiological research applications involving irradiation of small animals, it is difficult to achieve the same high precision dose distribution realized with human radiotherapy. The precision for irradiations performed with standard radiotherapy equipment is ±2 mm in each dimension, and is adequate for most human treatment applications. For small animals such as rodents, whose organs and tissue structures may be an order of magnitude smaller than those of humans, the corresponding precision required is closer to ±0.2 mm, if comparisons or extrapolations are to be made to human data. The Leksell Gamma Knife is a high precision radiosurgery irradiator, with precision in each dimension not exceeding 0.5 mm, and overall precision of 0.7 mm. It has recently been utilized to treat ocular melanoma and induce targeted lesions in the brains of small animals. This paper describes the dosimetry and a technique for performing irradiation of a single rat eye and lens with the Gamma Knife while allowing the contralateral eye and lens of the same rat to serve as the “control”. The dosimetry was performed with a phantom in vitro utilizing a pinpoint ion chamber and thermoluminescent dosimeters, and verified by Monte Carlo simulations. We found that the contralateral eye received less than 5% of the administered dose for a 15 Gy exposure to the targeted eye. In addition, after 15 Gy irradiation 15 out of 16 animals developed cataracts in the irradiated target eyes, while 0 out of 16 contralateral eyes developed cataracts over a 6-month period of observation. Experiments at 5 and 10 Gy also confirmed the lack of cataractogenesis in the contralateral eye. Our results validate the use of the Gamma Knife for cataract studies in rodents, and confirmed the precision and utility of the instrument as a small animal irradiator for translational radiobiology experiments.

Catecholamine and blood lactate responses to incremental rowing and running exercise

1994 ◽  
Vol 76 (3) ◽  
pp. 1144-1149 ◽  
Author(s):  
A. Weltman ◽  
C. M. Wood ◽  
C. J. Womack ◽  
S. E. Davis ◽  
J. L. Blumer ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Blood Lactate ◽  
Venous Catheter ◽  
Incremental Exercise ◽  
Plasma Epinephrine ◽  
O2 Uptake ◽  
Running Exercise ◽  
Rowing Ergometer ◽  
Per Se

Ten collegiate rowers performed discontinuous incremental exercise to their tolerable limit on two occasions: once on a rowing ergometer and once on a treadmill. Ventilation and pulmonary gas exchange were monitored continuously, and blood was sampled from a venous catheter located in the back of the hand or forearm for determination of blood lactate ([La]) and plasma epinephrine ([Epi]) and norepinephrine ([NE]) concentrations. Thresholds for lactate (LT), epinephrine (Epi-T), and norepinephrine (NE-T) were determined for each subject under each condition and defined as breakpoints when plotted as a function of O2 uptake (VO2). For running, LT (3.76 +/- 0.18 l/min) was lower (P < 0.05) than Epi-T (4.35 +/- 0.14 l/min) and NE-T (4.04 +/- 0.19 l/min). For rowing, LT (3.35 +/- 0.16 l/min) was lower (P < 0.05) than Epi-T (3.72 +/- 0.22 l/min) and NE-T (3.70 +/- 0.18 l/min) and was lower (P < 0.05) than LT for running. Within each mode of exercise, Epi-T and NE-T did not differ. Because LT occurred at a significantly lower VO2 than either Epi-T or NE-T, we conclude that catecholamine thresholds, per se, were not the cause of LT. However, for both modes of exercise LT occurred at a plasma [Epi] of approximately 200–250 pg/ml (rowing, 221 +/- 48 pg/ml; running, 245 +/- 45 pg/ml); these concentrations are consistent with the plasma [Epi] reported necessary for eliciting increments in blood [La] during Epi infusion at rest. Plasma [NE] at LT differed significantly between modes (rowing, 820 +/- 127 pg/ml; running, 1,712 +/- 217 pg/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Adaptation of SARS-CoV-2 in BALB/c mice for testing vaccine efficacy

Science ◽  
2020 ◽  
pp. eabc4730 ◽  
Author(s):  
Hongjing Gu ◽  
Qi Chen ◽  
Guan Yang ◽  
Lei He ◽  
Hang Fan ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Inflammatory Responses ◽  
Protective Efficacy ◽  
Small Animal ◽  
Spike Protein ◽  
Mouse Lung ◽  
Receptor Binding Domain ◽  
Intranasal Inoculation ◽  
Adaptive Mutations ◽  
Small Animal Models

The ongoing COVID-19 pandemic has prioritized the development of small animal models for SARS-CoV-2. Herein, we adapted a clinical isolate of SARS-CoV-2 by serial passaging in the respiratory tract of aged BALB/c mice. The resulting mouse-adapted strain at passage 6 (termed MASCp6) showed increased infectivity in mouse lung, and led to interstitial pneumonia and inflammatory responses in both young and aged mice following intranasal inoculation. Deep sequencing revealed a panel of adaptive mutations potentially associated with the increased virulence. In particular, the N501Y mutation is located at the receptor binding domain (RBD) of the spike protein. The protective efficacy of a recombinant RBD vaccine candidate was validated using this model. Thus, this mouse-adapted strain and associated challenge model should be of value in evaluating vaccines and antivirals against SARS-CoV-2.

A plethysmographic technique for direct measurement of airway resistance in hamsters

1989 ◽  
Vol 66 (4) ◽  
pp. 1990-1994 ◽  
Author(s):  
S. Sato ◽  
S. Kato ◽  
E. Terada ◽  
K. Takahashi ◽  
S. Yasui
Keyword(s):  
Airway Resistance ◽  
Flow Sensor ◽  
Small Animals ◽  
Hot Wire ◽  
Pulmonary Resistance ◽  
Coefficients Of Variation ◽  
A New Technique ◽  
Male Golden Hamsters ◽  
Microflow Sensor ◽  
Gas Volume

We have developed a new technique to directly measure airway resistance (Raw) in small animals with a pressure-type body plethysmograph equipped with a hot-wire microflow sensor. Seventeen male golden hamsters weighing 70–84 g were studied. Change in alveolar pressure (delta PA) was calculated from total gas volume and the respired volume difference through the flow sensor between the midpoints of the tidal excursion curve, reflecting the thorax movement. The ratio of delta PA to the flow difference between those two midpoints gave Raw. Raw was compared with pulmonary resistance, and inspiratory and expiratory resistances were also compared. Raw was 0.44 +/- 0.06 (SE) cmH2O.ml-1.s. Mean of the coefficients of variation of Raw was 19.6 +/- 3.2% (SE). Raw was well correlated with pulmonary resistance (r = 0.93). We demonstrated that Raw could be directly measured in small animals with a hot-wire flow sensor and a plethysmographic technique, and the values were well correlated with previously reported pulmonary resistance.

A new method for analyzing multiple-breath nitrogen washout curves

1980 ◽  
Vol 48 (2) ◽  
pp. 265-272 ◽  
Author(s):  
R. W. Light ◽  
R. B. George ◽  
G. R. Meneely ◽  
L. J. Chouest ◽  
R. H. Rosekrans
Keyword(s):  
Airway Obstruction ◽  
Nitrogen Concentration ◽  
Coefficient Of Determination ◽  
Nitrogen Washout ◽  
Lung Clearance Index ◽  
Residual Capacity ◽  
Two Indices ◽  
The Individual ◽  
End Tidal ◽  
Washout Curves

Multiple-breath nitrogen washout (MBNW) curves from 39 normal and 45 patients with varying degrees of airway obstruction were analyzed with the following equation: log log [(F0N2 - F infinity N2)/(FN2 - F infinity N2)] = B log (V/FRC) +A, where F0N2 is the initial, F infinity N2 is the equilibrium, and FN2 is the end-tidal fractional nitrogen concentration after a volume (V) of air in liters have been exchanged, and FRC is the measured functional residual capacity of the individual. All 84 curves were well described with the equation when all points corresponding to FN2 below 0.40 were used. The coefficient of determination (r2) exceeded 0.990 in 56/84 (67%) of the transformed curves and the lowest coefficient of determination was 0.946. This suggests that the MBNW can be described by two numbers, B called the index of uniformity, and A the index of efficiency. The ability of these two indices and the lung clearance index (LCI) to identify individuals as abnormal and to separate groups with varying degrees of airway obstruction was compared. B identified more individuals (33/45) as abnormal than did A(15/45) or LCI (19/45). B was also superior to A or LCI in separating groups with varying degrees of airway obstruction. This analysis allows the complex MBNW curve to be described by two numbers that vary depending on the degree of airway obstruction.

Oxygen-induced alteration of ventilation-perfusion relationships in rats

1979 ◽  
Vol 47 (5) ◽  
pp. 1112-1117 ◽  
Author(s):  
W. E. Truog ◽  
M. P. Hlastala ◽  
T. A. Standaert ◽  
H. P. McKenna ◽  
W. A. Hodson
Keyword(s):  
Gas Exchange ◽  
Pulmonary Gas Exchange ◽  
Inert Gas ◽  
Base Line ◽  
Small Animals ◽  
Difference Curve ◽  
Oxygen Breathing ◽  
Anesthetized Rats ◽  
Effect Of Oxygen ◽  
Breathing Room

The effect of oxygen breathing on shunt and ventilation-perfusion ratios (VA/Q) in anesthetized rats was studied using a modification of the multiple inert gas elimination technique. Base-line analyses showed hypoxemia in some animals breathing room air (arterial O2 tensions 48-70 Torr) associated with intrapulmonary shunts ranging from 0 to 22%, and variable low VA/Q lung regions as determined by calculation of the inert gas arterial-alveolar difference curve. Of nine rats that breathed 100% oxygen for 30 min, three showed increases in shunt (0% leads to 19%, 1.5% leads to 16%, 11% leads to 40%). These three animals had larger preexisting low VA/Q regions than the six that developed no shunt (0.48 +/- 0.15 vs. 0.17 +/- 0.03 (mean +/- SD); P less than 0.05). These data are compatible with the theory of absorption atelectasis. This study documents the usefulness of the inert gas elimination technique for studying pulmonary gas exchange problems in small animals.

scholarly journals Tomographic Ultrasound and LED-Based Photoacoustic System for Preclinical Imaging

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2793 ◽  
Author(s):  
Kalloor Joseph Francis ◽  
Richell Booijink ◽  
Ruchi Bansal ◽  
Wiendelt Steenbergen
Keyword(s):  
Small Animal Imaging ◽  
Small Animal ◽  
Tomographic Imaging ◽  
Acquisition Time ◽  
Small Animals ◽  
Acoustic Detection ◽  
Functional Capability ◽  
Treatment Progress ◽  
Linear Transducer ◽  
Animal Imaging

Small animals are widely used as disease models in medical research. Noninvasive imaging modalities with functional capability play an important role in studying the disease state and treatment progress. Photoacoustics, being a noninvasive and functional modality, has the potential for small-animal imaging. However, the conventional photoacoustic tomographic systems use pulsed lasers, making it expensive, bulky, and require long acquisition time. In this work, we propose the use of photoacoustic and ultrasound tomographic imaging with LEDs as the light source and acoustic detection using a linear transducer array. We have demonstrated full-view tomographic imaging of a euthanized mouse and a potential application in liver fibrosis research.

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