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1.
Packed canine red blood cells (RBCs) stored in the anticoagulant-preservative solution citrate-phosphate-dextrose-adenine (CPDA-1) were studied at 1, 10, 20, 30, and 40 days. The extracellular concentrations of potassium and sodium, erythrocyte mean corpuscular volume, and osmotic fragility increased during storage (P less than 0.05). There was a decrease in the pH, plasma concentration of glucose, and erythrocyte concentrations of 2,3-diphosphoglycerate (2,3-DPG) and adenosine-5'-triphosphate (P less than 0.05). Erythrocyte 2,3-DPG concentration decreased by 54% within the first 24 hours of storage (P less than 0.001). Posttransfusion viability (PTV) decreased from 90% on day 1 to 46% on day 40 (P less than 0.05). The PTV of the RBCs stored for 10 and 20 days complied with the Food and Drug Administration (FDA) standard. Although there are marked biochemical and hematologic changes in stored packed red blood cells (pRBCs), 20-day-old units may be expected to be of acceptable quality. The sharp decrease in 2,3-DPG concentration suggests a reduction in oxygen carrying capacity in erythrocytes stored as pRBCs. Hyperkalemia occurs during storage of pRBCs and does not appear to be associated with high intraerythrocytic potassium concentrations.  相似文献   

2.
Six thoroughbreds were used in each of three trials to examine the effect of potassium depletion on exercise-associated muscle damage. Horses were exercised after a control period (Treatment 1), a 72-hour fast (Treatment 2), and furosemide and sodium bicarbonate (Treatment 3). During the preexercise period, feed withdrawal for 72 hours caused decreases in body weight, plasma sodium, chloride, and serum calcium. There were no changes in plasma potassium, erythrocyte potassium, or serum creatine phosphokinase (CK) activity. Furosemide and sodium bicarbonate administration resulted in a decrease in plasma potassium, chloride, serum calcium, and magnesium in the pre-exercise period. Erythrocyte potassium and serum CK activity were unchanged. Body weight initially decreased following furosemide and sodium bicarbonate and then increased upon access to water. In all three treatment groups plasma sodium, potassium, L-lactate, serum calcium, and magnesium were increased immediately following exercise. There was a significant increase (P less than 0.05) in serum CK activity in the furosemide and sodium bicarbonate-treated horses compared to control and withholding feed treatment groups by 30 minutes following exercise. Erythrocyte potassium was decreased immediately following exercise in the furosemide and sodium bicarbonate group but not in the other treatment groups. Potassium depletion may play a role in exercise-induced muscle damage but could not be implicated as the sole cause of the serum CK activity increase in this study.  相似文献   

3.
Nine Thoroughbred horses were assessed to determine the normal response of insulin, glucose, cortisol, plasma potassium (K) and erythrocyte K through conditioning and to exercise over 400 and 1,000 m. In addition, adrenaline, noradrenaline, cortisol, plasma K, erythrocyte K and L-lactate concentrations were evaluated in response to maximal exercise with and without the administration of acepromazine. Conditioning caused no obvious trends in plasma K, erythrocyte K, insulin or glucose concentration. Serum cortisol increased (P less than 0.05) from the initial sample at Week 1 to Weeks 4 and 5 (attributed to a response to training), and then decreased. During conditioning, three horses had low erythrocyte K concentrations (less than 89.3 mmol/litre). Further work is needed to define the significance of low erythrocyte K concentrations in the performance horse. In all tests maximal exercise increased plasma K, glucose and cortisol concentrations, whereas insulin and erythrocyte K concentrations decreased. Thirty minutes following exercise, plasma K and erythrocyte K concentrations returned to resting values; whereas glucose and cortisol concentrations continued to increase and the insulin concentration also was increased. The magnitude of the changes varied for pre-conditioned vs post-conditioned exercise tests and the duration of exercise. The administration of acepromazine prior to exercise over 1,000 m failed to alter the circulating noradrenaline and adrenaline concentrations in anticipation of exercise or 2 mins following exercise. Acepromazine administration, however, did cause lower L-lactate concentration 2 mins (P less than 0.03) and 30 mins (P less than or equal to 0.005) following exercise. Also, erythrocyte K showed a delayed return to baseline levels at 30 mins post exercise. Further evaluation of these trends may help explain the beneficial role acepromazine plays in limiting signs of exertional rhabdomyolysis when administered prior to exercise.  相似文献   

4.
Changes in equine metabolic characteristics due to exercise fatigue   总被引：1，自引：0，他引：1  
Eight horses exercised to fatigue were used to characterize the resulting changes in blood pH, in blood lactate, free fatty acid, bicarbonate, and ammonia concentrations, and in muscle glycogen concentrations. The exercise test was conducted at a speed of 4.5 m/s on a motorized equine treadmill set at a 9% grade. At fatigue, all variables differed significantly (P less than 0.05) from base-line values. Heart rate averaged 191.1 +/- 6.5 beats/min at fatigue, and the plasma lactate concentrations increased from 7.8 +/- 0.95 mg/dl to 94.3 +/- 19.2 mg/dl. Ammonia concentrations increased from 66.7 +/- 6.9 mumol/L before exercise to 136.9 +/- 18.6 mumol/L at fatigue. Bicarbonate concentrations decreased from 31.3 +/- 0.4 mM to 21.1 +/- 1.8 mM, and pH decreased from 7.37 +/- 0.01 to 7.28 +/- 0.04. Free fatty acid concentrations were higher at fatigue and increased throughout the recovery period. Exercise resulted in a 25% decrease of muscle glycogen concentration in gluteus medius specimens.  相似文献   

5.
The concentrations of furazolidone (FZ) in plasma and milk were measured in goats treated orally with the drug at a dose of 10 mg kg-1 daily for 5 days. The maximum plasma concentrations obtained were 1.57 +/- 0.52 micrograms ml-1 (n = 5) 8 h after the first dose, and 2.13 +/- 0.11 micrograms ml-1 (n = 4) 6 h after the fifth dose. The maximum milk concentration was 0.88 +/- 0.32 micrograms ml-1 (n = 4) 8 h following the administration of a single dose. Using a colorimetric method, FZ was not detectable in goats' liver or muscle after the recommended therapeutic dose (10 mg kg-1, 5 days). However, using an HPLC method, the drug was detected 24 h after the treatment in the gluteal muscle and liver at concentrations of 0.26 +/- 0.01 microgram g-1 (n = 5) and 0.10 +/- 0.02 microgram g-1 (n = 5), respectively. The drug concentrations decreased significantly (P less than 0.05-0.01) at 3, 5 and 7 days after treatment, and no measurable concentrations were found after 10 days.  相似文献   

6.
In one study, a comparison was made of the concentrations and ratios of certain blood cations in 2 groups of cows with milk fever, one showing normal consciousness (n = 8) and the other depressed consciousness (n = 24). There were no significant differences in the mean concentrations of serum total calcium, plasma inorganic phosphorus and potassium, erythrocyte sodium and potassium, the serum calcium/serum magnesium ratio or the plasma sodium/erythrocyte sodium ratio. There were significant differences (all P less than 0.05) in the mean (+/- SD) concentrations of serum magnesium and plasma sodium concentrations, and the plasma sodium/serum magnesium ratio of 0.8 +/- 0.28 vs 1.2 +/- 0.37 mmol/l, 155 +/- 3.0 vs 147 +/- 6.4 mmol/l and 180 +/- 40.1 vs 116 +/- 34.1 for normal vs depressed cows, respectively. In a second study, a comparison was made of the concentrations and ratios of the same blood cations in 3 groups of cows in different positions when attended for milk fever, namely standing (n = 6), sternal recumbency (n = 24) and lateral recumbency (n = 31). There were no significant differences between the mean concentrations or ratios of any of the cations.  相似文献   

7.
Six horses gavaged with a commercial brodifacoum (BDF)-containing bait (Talone) at a dosage of 0.125 mg of BDF/kg of body weight showed weight loss, severe hypocoagulability and hemogram alterations. Four of the horses became depressed and anorectic; one required vitamin K1 therapy. Increases in clotting times were observed at 24 h in the partial thromboplastin time (PTT) followed by the thrombotest (TBT) and one-stage prothrombin time (PT) at 48 h. Elevated mean PTT, PT and TBT were observed from days 4 to 8 (p less than 0.05) with levels returning to pretreatment levels by day 12. Maximum prolongation was a fourfold increase in PTT (day 4), a 2.5-fold increase in TBT (day 6) and a twofold increase in PT (day 6). Thrombin clotting times remained unchanged. In two horses prolongation in clotting time did not normalize until day 23. The mean hematocrit (0.38 +/- 0.01 L/L) was decreased (p less than 0.05) from day 8 (0.33 +/- 0.02 L/L) to day 14 (0.33 +/- 0.01 L/L). The hemoglobin concentration and erythrocyte numbers were decreased (p less than 0.05) from day 6 (20.1%, 17.6% respectively) to day 14 (22%, 20% respectively). Platelet counts decreased on day 6 (17.2%) to nine (14.6%). No other significant changes were observed in routine hematological and serum biochemical parameters. Peak plasma concentrations of BDF occurred 2 to 3 h after oral administration; two horses had detectable levels of BDF at nine days. Pharmacokinetic evaluation indicated that BDF has a half-life of 1.22 +/- 0.22 days, a body clearance of 1073.1 +/- 53.21 mL/kg/day, a volume of distribution of 1853.7 +/- 26.41 ng-day/mL and closely approximates a one-compartment model in the elimination phase.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
Thirty Angus steers averaging 357 kg were used to: 1) determine the effect of feeding lasalocid (33 mg/kg diet) on mineral metabolism and 2) determine the effects of varying dietary sodium (Na) and potassium (K) on finishing steers fed lasalocid. Treatments consisted of: 1) control (.25% Na, .5% K); 2) lasalocid (.05% Na, .5% K); 3) lasalocid (.25% Na, .5% K); 4) lasalocid (.05% Na, 1.4% K) and 5) lasalocid (.25% Na, 1.4% K). Ruminal fluid and blood samples were collected on d 28 and 90 of the 102-d study. Gain and feed conversion tended to be higher for steers fed lasalocid with the exception of the .05% Na, 1.4% K treatment. Control steers had lower (P less than .05) erythrocyte K concentrations, reduced (P less than .05) soluble concentrations of magnesium and copper in ruminal fluid and decreased plasma concentrations of zinc (P less than .05) and phosphorus (P less than .10) at 90 d compared with steers fed lasalocid and similar concentrations of Na (.25%) and K (.5%). Increasing dietary Na from .05 to .25% in the presence of lasalocid increased (P less than (P less than .05) molar proportion of ruminal acetate at 28 and 90 d reduced (P less than .05) propionate at 90 d. Increasing K from .5 to 1.4% decreased (P less than .01) soluble Na and increased (P less than .01) soluble K concentrations in ruminal fluid. Steers fed lasalocid (.25% Na, .5% K) had lower concentrations of K (P less than .10) and zinc (P less than .10) in liver than control steers. Sodium and K level also affected tissue concentrations of certain minerals. Results suggest that dietary Na and K influence mineral metabolism and that dietary Na affects ruminal molar proportion of acetate in cattle fed lasalocid.  相似文献   

9.
This study was conducted to investigate the relationships between the concentrations of potassium, sodium, calcium and magnesium of plasma and muscle in horses, as interactions between these ions can be important in the development of muscle cell injury. Blood samples and gluteal muscle biopsies were taken from 20 healthy Standardbreds to determine the potassium concentration in plasma (cK+(P)), red blood cells (cK+(RBC)), and muscle (cK+(M)), and the calcium and magnesium concentrations in plasma and muscle. No correlations were found between cK+(P), cK+(RBC), and cK+(M). Significant positive correlations were found between cK+(M) and muscle magnesium (p<0.01); and cK+(P) and plasma calcium (p<0.005). Significant negative correlations were found between cK+(M) and the percentage of muscle water (p<0.005); and the muscle magnesium and calcium concentrations (p<0.02).  相似文献   

10.
Muscle biopsy samples were collected from the left middle gluteal muscle of the horses participating in day 2 (speed and endurance test) of a three day event. Six Thoroughbred horses were biopsied the day before and within 30 minutes of completion of the speed and endurance test. Serial muscle sections were reacted histochemically for myosin adenosine triphosphatase activity after acid pre-incubation to demonstrate Type I, IIA and IIB fibers and the glycogen content in the individual fibers was assessed using the periodic acid Schiff (PAS) reaction. Total glycogen in muscle was measured fluorometrically after hydrolysis to glucose. A significant decrease (P less than 0.001) in total muscle glycogen of 306.0 +/- 34.6 mmoles glucose units/kg (dry weight) (mean +/- SE) occurred when samples collected before exercise were compared to those collected following exercise. A significant decrease (P less than 0.05) in the percentage of Type I fibers having medium PAS staining intensity occurred when pre and post-exercise samples were compared. Significant decreases (P less than 0.01 and P less than 0.001 respectively) in the percentage of Type IIA and IIB fibers classified as having high PAS staining intensity occurred when post-exercise samples were compared with those pre-exercise. There were significant increases (P less than 0.01 and P less than 0.001 respectively) in the percentage of Type IIA and IIB fibers classified as having medium PAS staining intensity when the samples collected after the exercise were compared with those before the exercise.  相似文献   

11.
Sodium propionate (3 mmol/kg) was injected IV into 8 nonlactating dairy cows before and after 6 days (144 hours) of fasting. During fasting, long-chain fatty acids in plasma increased from 0.30 +/- 0.05 (SE) mM to 1.09 +/- 0.15 mM (P less than 0.05). Liver fat increased from 0.5 +/- 0.3% to 9.3 +/- 1.7% (P less than 0.05). Half-life of injected sodium propionate increased significantly (P less than 0.05) from 7.6 +/- 0.5 minutes to 10.1 +/- 1.0 minutes during fasting. Sulfobromophthalein half-life did not change significantly (3.8 +/- 0.79 minutes to 5.3 +/- 1.3 minutes). Increases in plasma glucose concentrations after propionate loading were significantly less during fasting than during feeding. Thus, the change in glucose concentration served as an indicator of hepatic conversion of propionate to glucose. Increases in glucose concentration of less than 2 mM at 30 minutes after propionate loading indicated that liver function was altered in nonlactating dairy cows.  相似文献   

12.
This study investigated the effects of excess cortisol on physiological mechanisms that resist dehydration in Bos indicus steers (n = 31, 2 yr of age, 193 +/- 21.47 kg mean BW) during a 90-h period. Steers were assigned randomly to one of four groups: 1) no water/no cortisol (n = 8), 2) water/no cortisol (n = 8), 3) no water/cortisol (n = 8), and 4) water/cortisol (n = 7). Animals allocated to cortisol treatment groups were given 0.1 mg x kg BW(-1) x h(-1) of hydrocortisone suspended in isotonic saline for the duration of the study. Total body water, osmolality, hematocrit, urine output, feed and water intake, and plasma concentrations of arginine vasopressin (AVP), angiotensin II (AII), electrolytes, total protein, and albumin were determined at 24-h intervals for 90 h. In the presence of excess plasma cortisol, total body water was maintained in the presence of a water deprivation insult for 90 h, whereas hydration indices, such as total plasma protein and albumin, did not change, supporting the body water data. However, plasma osmolality increased for the water-deprived groups from 24 h (P = 0.008). Hematocrit did not reflect dehydration in any group. Water deprivation induced an increase in endogenous plasma cortisol concentrations after 60 h of the study (P = 0.028). Plasma concentrations of AVP increased with water deprivation (P = 0.006). Excess cortisol decreased the plasma concentration of AVP at 72 h only (P = 0.027) and suppressed plasma concentrations of AII at 24 and 72 h (P < 0.001 and P = 0.036, respectively). Animals treated with excess cortisol maintained urinary output for 48 h before decreasing at 72 h (P = 0.057), although there was no effect on water or feed intake. Water deprivation increased plasma sodium concentrations (P < 0.05) until 72 h, whereas potassium decreased under the influence of excess plasma cortisol (P = 0.001) at 24 h. Water deprivation increased plasma chloride concentration at 72 and 90 h (P = 0.051 and P = 0.026, respectively). Plasma phosphorus decreased at 24 h (P = 0.001) and remained at lesser concentrations for the duration of the study (P = 0.05). These results highlight the complexity of endocrine interactions associated with water balance in Bos indicus steers. We accept our hypothesis that, in the presence of excess cortisol, the renin-angiotensin-aldosterone axis is suppressed; however, homeostasis is achieved through other physiological systems.  相似文献   

13.
One young male and five female goats aged from four months to mature full-mouthed were handled by stroking and raising the jugular vein intermittently for one minute each day for four days. A control group was kept in a similar pen out of sight of the test group for the four days and approached only when attended for pen cleaning and feeding. On the fifth day, heparinised blood samples were taken once hourly for a period of three hours by jugular venepuncture from both groups. After processing, the samples were examined for packed cell volumes, plasma and erythrocyte potassium and sodium concentrations. Analysis of variance of the data showed a significant (P less than 0.01) reduction in erythrocyte potassium concentration in the unhandled group (76.3 mmol/l to 74.2 mmol/l) from Time 0 to Time 1, and a similarly significant increase in levels in the handled group (73.7 mmol/l to 78.0 mmol/l) from Time 0 to Time 1. There was also a significant difference (P less than 0.05) in packed cell volumes between the unhandled and handled groups at Time 0 and Time 1 (28.6% v 25.2% and 27.6% v 25.0% respectively). There were no significant differences between the two groups in plasma sodium, plasma potassium or erythrocyte sodium.  相似文献   

14.
Erythrocyte insulin receptor binding measurements were evaluated in 8 dogs with spontaneous hyperadrenocorticism. These dogs had normal serum glucose concentration, with normal to high serum insulin concentration (range, 45 to 1,400 pmol/L; normal, 40 to 170 pmol/L). Dogs with hyperadrenocorticism had significant (P less than 0.01) decrease in mean +/- SEM percentage of maximal binding for erythrocyte insulin receptors (2.25 +/- 0.21%), compared with results in 11 clinically normal pet dogs (4.29 +/- 0.42%). The decrease in erythrocyte receptor binding was attributed to significant (P less than 0.01) decrease in high-affinity receptor sites in dogs with hyperadrenocorticism (14.5 +/- 2.8), compared with clinically normal dogs (31.2 +/- 4.3). Significant differences in receptor affinity were not apparent between the 2 groups. Percentage of maximal binding for erythrocyte insulin receptors for dogs with hyperadrenocorticism was inversely correlated with serum insulin concentration (r = -0.85, P less than 0.01). Results indicate that the observed decrease in erythrocyte insulin receptor binding could contribute to insulin resistance and hyperinsulinemia associated with hyperadrenocorticism. Alternatively, decreased binding of insulin receptors in animals with hyperadrenocorticism may result from down-regulation secondary to hyperinsulinemia itself caused by insulin resistance at a postreceptor site (decreased responsiveness).  相似文献   

15.
Knowledge of pathogenesis of sexual dysfunctions at altered thyroid activity is limited by the knowledge of multiple and ubiquitous action of its hormones throughout the organism. One of the possibilities of modulatory influence of thyroid hormones on sexual functions can be realized through the participation of thyroxine and triiodothyronine in the synthesis and metabolism of primary substrate of steroid synthesis--cholesterol. The presented work is aimed at the study of simultaneous dynamic changes of concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) during synchronization of the rutting period and gravidity at parallel correlative evaluation of mutual relations of the followed parameters in ten Merino sheep in the seasonal period. Synchronization was achieved by chlorsuperlutin (Agelin--vaginal swabs, Spofa; 20 mg of chlorsuperlutin/swab) and PMSG (500 I. U./animal). Blood was sampled by means of a jugular vein puncture at the time of swab insertion (-13th day) and after three (-10th day) and seven (-7th day) following days, at the removal of swabs and application of PMSG (-3rd day), on the day of insemination (zero day), on the 7th, 14th and 17th day and in the middle of the 2nd, 3rd, 4th and 5th month of gravidity. In the phase of oestrus synchronization a significant increase of E2 concentrations on days -7 and -3 of the experiment (0.47 +/- 0.079 and 0.542 +/- 0.177 nmol.l-1 of serum, P less than 0.001; P less than 0.001) was observed compared to the E2 values on day -13 (0.084 +/- 0.036 nmol.l-1 of serum). Parallel to these observations, marked intermittent changes of T4 (Tab. I, Graph 1) were recorded with the lowest values of this parameter observed on days -10 (41.75 +/- 20.23, P less than 0.05) and -3 (50.22 +/- 18.77, P less than 0.05) and the highest on day -7 (96.77 +/- 17.51 nmol.l-1, P less than 0.01) and day zero (85.40 +/- 19.59 nmol.l-1 of serum, P less than 0.05) in comparison with the -13th day (67.22 +/- 18.29 nmol.l-1 of serum). Concentrations of P4 (Tab. I, Graph 4) declined to the lowest values on day zero observation (0.09 +/- 0.08 nmol.l-1 of serum, P less than 0.05 vs 3.40 +/- 3.61 nmol.l-1 on day -13). No significant changes of concentrations of T3 (Tab. I, Graph 2) and Chol (Tab. I, Graph 5) were observed during oestrus synchronization. During gravidity, concentrations of E2 (Tab. I Graph 3) showed an increasing trend compared to the -13th day.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
Characteristics of minature end-plate potentials (MEPP) of isolated external intercostal muscle preparations of 7 mammalian species (dog, cat, pig, horse, cow, and goat) including 1 marsupial (opossum, Didelphis marsupialis) were determined with intracellular microelectrodes. Mean amplitude (+/- standard error of MEPP for all species was 0.60 +/- 0.06 mV, and the range was 0.28 mV (opossum) to 1.07 mV (pig). Amplitude was inversely correlated (P less than 0.01) with muscle fiber diameter which ranged from 93 mum (opossum) to 51 mum (pig). Mean values for rise time, half-decay time, and frequency of MEPP for all species were 0.88 +/- 0.07 msec, 1.89 +/- 0.16 msec, and 0.44 +/- 0.12 MEPP/second, respectively. Species differences among these measurements were not statistically significant. Resting potentials ranged from 64 mV (pig) to 75 mV (cow and opossum). Amplitude of MEPP was reduced significantly by d-turbocurarine (0.06 muM) only in preparations from the dog (P less than 0.01), pig (P less than 0.05), cow (P less than 0.01), and goat (P less than 0.01), suggesting species variations in sensitivity to this neuromuscular blocking agent. Frequency of MEPP decreased in the prescence of d-tubocurarine, but the change was not significant. The techniques utilized in this study and the results obtained will have application in evaluation of intercostal muscle biopsy preparations from these species when affected by myasthenic diseases.  相似文献   

17.
Changes in the concentrations of B, Ca, Fe, K, Mg, Mn, Na, P, S, Sr and Zn in the liquid phase in sheep rumen were determined to obtain information on their rate of disappearance from the soluble pool after feeding. Sheep were fed alfalfa (Medicago sativa) hay hourly. The concentration of infused Cr(III)-EDTA into the rumen (over a period of 4 d) was used to establish steady-state conditions, after which feeding was stopped and the rapidly changing elemental concentrations in 30,000 x g ruminal supernatant fluid were determined by plasma emission spectrometry. The concentrations of all elements, apart from Fe, Na and P, decreased in a first-order manner over 5 h after feeding. For one sheep, these concentrations (microM) were: B, 199 to 126; Cr, 184 to 111; Ca, 4,150 to 1,130; K, 51,000 to 28,800; Mn, 11 to 4.2; Mg, 4,190 to 1,810 and Zn, 14 to 7.8. For S, first-order decay was observed over only the 0- to 2-h period (2230 microM to 865 microM). Phosphorus increased from 10.4 to 13.1 mM over the 5-h period, whereas Na remained constant (85 mM); this was attributed to saliva input. Mean half-lives for B (8.8 h), K (7.5 h) and Zn (5.3 h) were similar to those of Cr (6.3 +/- .3 h), the water flow marker. Mean half-lives of Ca (2.6 h), Mg (4.0 h), Mn (3.3 h), Sr (3.3 h) and S (1.8 h) were shorter (P less than .01) than that of the Cr marker.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
Adult mixed-breed dogs and Siberian Huskies were used to study erythrocyte cation and water contents, as well as sodium transport kinetics. Erythrocyte sodium, potassium, and water contents, as well as sodium efflux and influx kinetics, were measured. Lithium efflux studies were also performed, because previous studies reported involvement of this ion in sodium transport kinetics. Sodium, potassium, and water contents in erythrocytes from mixed-breed dogs were significantly (P less than 0.05) different from those of Siberian Huskies when cells were washed in an isotonic sodium-free medium. Lithium efflux in hypertonic choline chloride was found to be significantly (P less than 0.048) different in erythrocytes obtained from Siberian Huskies, compared with those from mixed-breed dogs. Additionally, sodium efflux in isotonic choline chloride was significantly (P less than 0.01) lower in erythrocytes isolated from Siberian Huskies. Under these experimental conditions, sodium efflux was inhibited by 10 mM LiCl in erythrocytes of both groups. Amiloride (0.2 mM) was found to be a potent inhibitor of Na+ and Li+ efflux. These data indicate that Na+ metabolism may be altered in erythrocytes of Siberian Huskies, and may provide important insight into some of the erythrocyte transport abnormalities associated with specific human diseases in which erythrocyte cation content and sodium transport kinetics are altered.  相似文献   

19.
When sheets of mucosa from the cecum of clinically normal horses were incubated in vitro with radiolabeled L-alanine, they could accumulate this amino acid against an apparent concentration gradient after 60 to 150 minutes of incubation. The active transport system for L-alanine was on the serosal surface of the mucosal sheet only. L-Alanine accumulation at 60 minutes was partly inhibited by 20 mM glycine (P less than 0.01), 0.5 mM ouabain (P less than 0.05), and Na deprivation (P less than 0.02). Anoxia for 60 minutes increased L-alanine accumulation, but had adverse effects on cell structure and intracellular cation distributions. Transmucosal fluxes induced a small, but significant (P less than 0.05), net secretion of L-alanine, and the mean (+/- SEM) transmucosal potential difference was 7.3 +/- 0.7 mV over the period of flux measurement. It was concluded that L-alanine was accumulated by the serosal surface of the cecal mucosa, possibly to provide substrate for tissue metabolism. There was no evidence that the cecal mucosa could actively transport this amino acid from the luminal bathing medium.  相似文献   

20.
The pharmacokinetics of flunixin meglumine was determined after its multiple (altogether 4 doses at 24-hours intervals) intravenous administration at a dose of 2.2 mg/kg body weight in six mature clinically healthy heifers. Plasma flunixin and its metabolite 5-hydroxyflunixin concentrations were analyzed with high-pressure liquid chromatography using an assay with a lower limit detection of 0.03 microg/ml for both substances. Plasma concentrations versus time curves were described by a two compartment open model. Mean plasma flunixin concentrations were similar on day 1 and 4, and than rapidly decreased (within 2 hours) from initial concentrations higher than 10 microg/ml to the concentrations lower than 1 microg/ml. The distribution phase of flunixin was short (t0.5 alpha = 0.29 +/- 0.16 and 0.18 +/- 0.04 on day 1 and 4, respectively) and the elimination phase was more prolonged (t0.5 beta = 3.30 +/- 0.60 and 3.26 +/- 0.22 on day 1 and 4, respectively). The mean residence time of flunixin was similar on day 1 (1.83 +/- 0.83) and 4 (1.88 +/- 0.46), and for 5-hydroxyflunixin this parameter was insignificantly (P > 0.05) higher on day 1 (5.49 +/- 2.22) as compared to that found on day 4 (3.99 +/- 2.17). The clearance of flunixin was similar on both examined days (0.23 +/- 0.12 on day 1 and 0.31 +/- 0.15 on day 4), and for 5-hydroxyflunixin was insignificantly (P > 0.05) lower on day 1 (2.37 +/- 1.21) as compared to that determined on day 4 (3.23 +/- 1.06). Our data indicate that multiple administration of flunixin did not alter significantly the parent drug and its metabolite concentrations in plasma, however may cause some small changes in pharmacokinetic parameters.  相似文献   

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