A comparative analysis of carbon dioxide displacement rates for euthanasia of the ferret

Narcosis and asphyxia in insects can be investigated by measuring the recovery time. This and other terms are defined, and suitable criteria of recovery are given. Simple techniques for the etherizing and gassing of Drosophila batches are described and the validity of the quantitative results obtained is shown. The recovery time is increased by the time of influx and by the concentration oj the narcotic. The shapes of the curves obtained in experimental Series are logarithmic (carbon dioxide asphyxiation), straight line (ether in some species), concave, convex or sigmoid (ether). It is suggested that the different forms of ether recovery curves are different parts of essentially similar curves, which one might explain by the joint action of two macrophases, one aqueous and one lipoid. Physiological factors determining recovery times are : (a) sex : females recover earlier from ether narcosis than males; (b) age: young flies recover earlier than older ones; (c) lack of food and moisture, which increases the recovery time ; and (d) chemical reaction: flies kept on acid food remain longer narcotized than flies-bred on an alkaline medium. Carbon dioxide lengthens recovery from ether narcosis and hydrocyanic acid immobilization when applied before the influx time and shortens it when applied during recovery-time. If administered during recovery, it also shortens the recovery from asphyxiation. Carbon monoxide and coal gas administered before narcotization can shorten the recovery time from ether narcosis. Under specified conditions corresponding to those, used during narcosis by Droso-phila-workers some differences in recovery time after etherization due to genetical differences could be established. Significant differences also exist between some Drosophila species, races and mutants in their resistance to carbon dioxide, asphyxiation and hydrocyanic acid.gas.

The metabolic actions of caffeine were investigated in the rat (90 mg/kg bw caffeine intravenously during 3 hours) and in human volunteers (35 mg/kg bw caffeine orally) in the fasting state. Additionally, the effects of caffeine were measured during simultaneous intravenous glucose infusion (0.25 mg/kg bw/h during 6 hours in humans and 1.8 mg/kg bw/h during 3 hours in the rat). In the fasting rat, intravenous caffeine caused an increase in the serum concentrations of glucose, urea, insulin, and free fatty acids, whereas a decrease in glucoplastic amino acids was found. As the liver glycogen concentration was not altered, the increase in blood glucose should be due to an increase in glyconeogenesis. During simultaneous application of carbohydrates and caffeine, the increases in the concentration of blood glucose and serum insulin were intensified, whereas the serum concentrations of lactate and urea as well as hepatic glycogen were not altered. In fasting male volunteers caffeine caused an increase in the concentrations of blood glucose, cortisol, insulin, free fatty acids, free glycerol and ketone bodies. During intravenous glucose infusion, caffeine intensified the decrease in serum phosphate induced by carbohydrates. Neither in volunteers nor in the experimental animal, an alteration in the concentrations of cholesterol or serum triglycerides or serum uric acid was effected by caffeine. It is concluded that high dosed caffeine causes peripheral insulin resistance in the human being as well as in the experimental animal. This peripheral insulin resistance is shown by the simultaneous large increases in concentrations of serum insulin, blood glucose and concentration of free fatty acids. In this situation insulin obviously is not able to inhibit lipolysis or gluconeogenesis nor to increase peripheral glucose utilisation. These metabolic effects of caffeine show some similarities to the metabolic situation in diabetes mellitus type 2 (Non Insulin Dependent Diabetes mellitus).

A 3-year-old female domestic ferret (Mustela putorius furo) with an insulinoma was treated because of a hypoglycemic crisis prior to scheduled pancreatectomy with concurrent nodulectomy. Previously, the ferret had clinical signs of lethargy and hind limb weakness; at that time, blood glucose concentration was low, and a tentative diagnosis (subsequently confirmed) of insulinoma was made. Prednisolone treatment (0.3 mg/kg [0.14 mg/lb], PO, q 12 h) did not improve clinical signs; the dosage was gradually increased over a 1-month course (1.8 mg/kg [0.82 mg/lb], PO, q 12 h) and maintained for 10 days. Overall, the treatment was ineffective, and the ferret remained lethargic and developed inappetence. At a reevaluation, the ferret had severe weakness and nonresponsiveness nearing a comatose state. Standard treatment with dextrose (1 mL of 50% solution, IV), and dexamethasone (1 mg/kg [0.45 mg/lb], SC) was administered with resultant improvement in mentation. The ferret was discharged from the hospital and then returned 3 days later for stabilization prior to pancreatectomy with concurrent nodulectomy. The day before surgery, the ferret was administered a glucagon constant rate infusion at a rate of 15 ng/kg/min (6.8 ng/lb/min), which resulted in an increase in blood glucose concentration to a euglycemic state and resolution of clinical signs of hypoglycemia. As illustrated by the case described in this report, a glucagon constant rate infusion can be used successfully for the emergency treatment of hyperinsulinemic-hypoglycemic crisis in insulinomic ferrets.

Using water to displace carbon dioxide adsorbed in coalcan preventcoal and gas outbursts. However, the mechanism of continuous waterinjection replacing adsorbed gases in coal has not been well studied.An experiment with the same water injection pressure and differentadsorption equilibrium pressures for displacing carbon dioxide wasconducted. The variation patterns of the amount of displaced carbondioxide, time, and water displacement rate, displacement ratio, andwater action ratio were analyzed. The modes of water injection displacingcarbon dioxide are discussed. The results show that the change inthe amount of displaced carbon dioxide consists of three stages: rapid,slow, and stop growth stages. For the same displacement time, as theadsorption equilibrium pressure rises, more carbon dioxide is displaced.The time displacement rate and water displacement rate can be dividedinto three stages: rising, peak, and dropping stages. As the adsorptionequilibrium pressure increases, the duration of the peak stage decreases,while the time and water displacement rates increase. At differentadsorption equilibrium pressures, the carbon dioxide displacementratio ranged from 45% to 54%, less than the natural desorption ratio.But the water action ratio containing the gas dissolution amount wasclose to or greater than the natural desorption ratio. Thus, the displacementeffect of flowing water accelerated the desorption of carbon dioxidein coal. The modes of carbon dioxide displacement by water injectioninclude water-displacement, gas-dissolution displacement, and gas-diffusion–dissolutiondisplacement. The findings of this study provide novel suggestionsfor preventing and controlling coal and gas outbursts.

We studied domestic ferrets (Mustela putorius furo) to evaluate the physiologic effects of routine surgery. Standard plasma biochemistry panels and 1H-NMR spectroscopy of heparinized whole blood were performed on samples taken 24 h prior to and immediately after surgery from female and male ferrets undergoing routine gonadectomy. Increases in plasma glucose, phosphorus, potassium, and creatine kinase concentrations associated with the duration of surgery were identified on plasma biochemistry panels. Whole-blood NMR spectra allowed us to identify 42 metabolites and one drug residue. Variations between pre- and postoperative metabolite concentrations were most pronounced for female ferrets, which underwent more prolonged surgery than males. Affected metabolites included organic acids and osmolytes (betaine, methylmalonate, <small>D</small>-lactate), fatty acids and lipids (2-hydroxy-3-methylbutyric acid), and amino acid groups (acetylglycine, alloisoleucine, leucine, and isoleucine). These findings indicate that 1H-NMR spectroscopy of whole blood provides insight into metabolic perturbations in domestic ferrets undergoing surgery that are not detected in routine clinical chemistry panels.

Intravenous chlorpromazine was found to cause rapid increases in plasma concentrations of glucose and long chain fatty acids in adult sheep of both sexes. α‐adrenergic blockade with phentolamine suppressed the increase in glucose concentration but not the increase in concentration of long chain fatty acids caused by chlorpromazine. β‐adrenergic blockade with propranolol suppressed the increase in concentration of long chain fatty acids but not the increase in glucose concentration caused by chlorpromazine. These results were consistent with the hypothesis that chlorpromazine caused a systemic release of epinephrine.

This datasheet on carbon dioxide asphyxiation in pigs covers Identity, Hosts/Species Affected, Diagnosis.

The 2013 AVMA Guidelines on Euthanasia recommend the use of very-low or low flow rates of 100% carbon dioxide to euthanize small rodents. Although inhalation of high concentrations of carbon dioxide are generally recognized as painful in humans, whether the use of these low-flow methods of euthanasia increase potential distress for rats is unclear. This study compared physiologic and behavioral markers of animal wellbeing for rats euthanized by using 10% volume displacement per minute (VD/min), 30% VD/min, and 70% VD/min of 100% carbon dioxide. Rats were recorded during euthanasia for subsequent behavioral scoring, and blood samples were taken after euthanasia for assessment of blood glucose and serum corticosterone levels. In this study, rats euthanized with 10% or 30% VD/min of 100% carbon dioxide demonstrated increases in various behaviors, such as rearing and standing, concurrent with increases in serum corticosterone. Rats euthanized with 70% VD/min of 100% carbon dioxide did not exhibit these changes. The results suggest that a euthanasia method of 70% VD/min of 100% carbon dioxide may minimize potential pain and distress and thus be more humane for rats, as compared with very-low- and low-flow methods of carbon dioxide euthanasia.

The surface electrocardiogram in domestic ferrets

We assessed the effects of prolonged reduction of plasma retinol concentrations (hyporetinolemia) on the distribution of tissue vitamin A (VA) and of its active compounds using a model of continuous recombinant human interleukin-6 (rhIL-6) infusion via osmotic minipumps in VA-sufficient male rats. Plasma retinol and retinol-binding protein (RBP) concentrations remained decreased and lower in rhIL-6-treated rats compared with controls from 7.5 h throughout 7 days of infusion (P < 0.001). This reduction was accompanied by a 68% increase in hepatic retinol concentration by 7 days (P < 0.05). Hepatic and renal retinyl palmitate and retinoic acid concentrations did not change, and renal megalin content remained unchanged; hepatic RBP concentrations were 41% lower in rhIL-6-treated rats compared with controls (P < 0.05). These results indicate that instead of being lost, retinol accumulated in the liver during inflammation and that hyporetinolemia was attributable to a decrease in the availability of hepatic RBP. A plausible consequence of the effect of rhIL-6-induced hyporetinolemia is that by 7 days tissues that are dependent on plasma retinol may become deprived of VA. These results have important implications in understanding the mechanism by which measles infection induces hyporetinolemia and VA deficiency of extrahepatic tissues.

The study included measuring the concentrations of each of the cumulative sugar HbA1C Glycosylated hemoglobin, urea, creatinine, uric acid, glucose, glucose uric acid, albumin, total protein and calcium, in addition to identifying the concentrations of some electrolytes (sodium, potassium, chloride, calcium) in (35) blood samples from patients with diabetic nephropathy (14 males, 12 females) aged (16-62) years who came to some laboratories in the city of Mosul and compared them to control samples (26) samples. The results showed a significant increase in cumulative sugar, uric acid, glucose and potassium concentrations in the serum of patients of both sexes. An insignificant increase in urea and creatinine concentrations and a significant decrease in albumin, sodium and chloride concentrations, while calcium and total protein did not show a significant difference compared to control samples. When comparing cases of infection between males and females, the results showed a significant increase in the cumulative sugar level for males and an insignificant increase in glucose concentration. In contrast, creatinine, uric acid, total protein and albumin did not significantly differ for males compared to infected females. Keywords cumulative glucose, biochemical variables, Diabetic

PurposeTo develop and optimize a method to monitor real-time mitochondrial function by measuring the oxygen consumption rate (OCR) in murine corneal biopsy punches with a Seahorse extracellular flux analyzer.MethodsMurine corneal biopsies were obtained using a biopsy punch immediately after euthanasia. The corneal metabolic profile was assessed using a Seahorse XFe96 pro analyzer, and mitochondrial respiration was analyzed with specific settings.ResultsReal-time adenosine triphosphate rate assay showed that mitochondrial oxidative phosphorylation is a major source of adenosine triphosphate production in ex vivo live murine corneal biopsies. Euthanasia methods (carbon dioxide asphyxiation vs. overdosing on anesthetic drugs) did not affect corneal OCR values. Mouse corneal biopsy punches in 1.5-mm diameter generated higher and more reproducible OCR values than those in 1.0-mm diameter. The biopsy punches from the central and off-central cornea did not show significant differences in OCR values. There was no difference in OCR reading by the tissue orientations (the epithelium side up vs. the endothelium side up). No significant differences were found in corneal OCR levels between sexes, strains (C57BL/6J vs. BALB/cJ), or ages (4, 8, and 32 weeks). Using this method, we showed that the wound healing process in the mouse cornea affected mitochondrial activity.ConclusionsThe present study validated a new strategy to measure real-time mitochondrial function in fresh mouse corneal tissues. This procedure should be helpful for studies of the ex vivo live corneal metabolism in response to genetic manipulations, disease conditions, or pharmacological treatments in mouse models.

Carbon dioxide euthanasia in rats: oxygen supplementation minimizes signs of agitation and asphyxia

Normal adult liver is uniquely capable of renewal and repair after injury. Whether this response represents simple hyperplasia of various liver elements or requires recapitulation of the genetic program of the developing liver is not known. To study these possibilities, we examined transcriptional programs of adult liver after partial hepatectomy and contrasted these with developing embryonic liver. Principal component analysis demonstrated that the time series of gene expression during liver regeneration does not segregate according to developmental transcription patterns. Gene ontology analysis revealed that liver restoration after hepatectomy and liver development differ dramatically with regard to transcription factors and chromatin structure modification. In contrast, the tissues are similar with regard to proliferation-associated genes. Consistent with these findings, real-time polymerase chain reaction showed transcription factors known to be important in liver development are not induced during liver regeneration. These three lines of evidence suggest that at a transcriptional level restoration of liver mass after injury is best described as hepatocyte hyperplasia and not true regeneration. We speculate this novel pattern of gene expression may underlie the unique capacity of the liver to repair itself after injury.

When using an anesthetic overdose to euthanize laboratory rodents, a secondary method of euthanasia is recommended to ensure that the apparent death is irreversible. This secondary method usually is accomplished through the collection of tissues that are required to complete the research project. However, frequently laboratory rodents must be euthanized because they cannot be used for studies; in these cases, caretakers must perform a secondary method of euthanasia. Performing physical methods of euthanasia, even on unconscious rodents, can contribute to compassion fatigue in these persons. The current study was designed based on existing literature regarding minimal exposure times for preweanling rats and mice euthanized with carbon dioxide. The study evaluated the minimal time that adult rats and mice must remain in 100% carbon dioxide for death to be irreversible on removal. Adult rats (14 stocks and strains) and mice (more than 40 stocks and strains) were euthanized using a 50% volume per minute displacement rate of carbon dioxide for 2 min. The cages were then left undisturbed for predetermined times, ranging from 0 to almost 12 min. Upon removal from the cage, the animals were stimulated to determine whether they could be resuscitated. If an animal recovered, it was euthanized by using a physical method of euthanasia, and a duration that was 30 s longer than the previous predetermined time was assessed using other animals. The study demonstrated that exposure times of at least 3 min in carbon dioxide reliably result in irreversible euthanasia of mice but that exposure times of at least 10.5 min in carbon dioxide were required to ensure irreversible euthanasia of rats. Although an irreversible death can be attained with carbon dioxide, the use of appropriate species-specific exposure times is critical.