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1.
Thermodilution cardiac output was compared with simultaneously determined aortic flow in 5 guinea pigs during thoracotomy. Total cardiac output was affected by volume expansion, adrenergic stimulation, and the volume of hemorrhage. For the equation y = mx, where y is aortic flow, x is thermodilution cardiac output, and m is the slope of the regression line, m = 0.88 +/- 0.02 (95% confidence interval). The SE of the regression was 27.8 ml/min. Thermodilution may have been overestimated because the aortic flow measurement did not take into account the coronary arterial blood flow, which is approximately 4% of total cardiac output in the guinea pig. Indicator loss (ie, temperature) also may be an important factor in the calculation of cardiac output, as determinations of thermodilution cardiac output were affected by sampling site in the guinea pig. Thermodilution appears to be a useful and reliable means of determining cardiac output in the guinea pig.  相似文献   

2.
A model system of feline or small canine cardiac output was used to produce known liquid flow rates in the range of 100 to 750 mL/min for comparison against a thermodilution technique of flow measurement. Thermal indicator size was decided by the thermal time concentration curve detected by the Edwards 9520A cardiac output computer. Ten consecutive readings for each flow were made. Regression analysis and Student's t-test were used to evaluate the results. The computer was found to give good correlation with the accurate flow measured by a graduated cylinder over a period of time (r = 0.99). An error of less than 7% overestimation of flow by thermodilution was found with flows greater than 200 mL/min (p less than 0.05). A significant error of more than 20% overestimation of the actual flow occurred with flows less than 200 mL/min (p less than 0.05). The Edwards 9520A computer was compared to the older Edwards 9510A model by averaged triplicate measurements at six different cardiac outputs in an anesthetized cat. The measurements were not significantly different (p less than 0.01). Thermodilution using an Edwards computer proves to be a promising tool in the measurement of low flows applicable to feline and small canine cardiac outputs.  相似文献   

3.
Comparison of three methods for cardiac output determination in cats   总被引:5,自引:0,他引:5  
Cardiac output (CO) was measured in sodium pentobarbital-anesthetized cats over a wide range of blood flow rates. In 10 cats, CO was measured simultaneously, using Fick determination and thermodilution techniques. Echocardiography was used to estimate contractility of the heart by measuring percentage change in minor diameter and velocity of circumferential fiber shortening. These indices were compared with CO by the other techniques. Echocardiographic equations used for CO determination in man were evaluated for reliability in the cat. Thermodilution and Fick determination correlated best with low CO (r = 0.89) and less with intermediate (r = 0.69) and high (r = 0.75) CO. Percentage change in minor diameter and velocity of circumferential fiber shortening correlated with thermodilution measurements of the cardiac index (r = 0.71 and r = 0.84, respectively). The value of echocardiography for CO estimation was questionable, using existing equations. Fick determination of CO was more inconsistent and was more prone to technical error than was thermodilution.  相似文献   

4.
OBJECTIVE: To describe the effects of changes in circuit volume and oxygen inflow rate on inspired oxygen concentration for a large animal circle anesthetic system. STUDY POPULATION: A large animal circle anesthetic system, a 10 L/min flowmeter, and 20- and 40-L breathing bags. PROCEDURE: Circuit volume was determined by a carbon dioxide dilution technique. Oxygen flow rates of 3, 6, and 10 L/min were delivered to the circuit with the large breathing bag, and a flow rate of 6 L/min was used with the small bag. Gas samples were collected during a 20-minute period. The time constant (tau) and half-time (T1/2) were calculated and compared with measured values. RESULTS: Mean +/- SEM volume of the breathing circuit with a 20- and 40-L breathing bag was 32.97 +/- 0.91 L and 49.26 +/- 0.58 L, respectively. The tau from measurements was 11.97, 6.10, and 3.60 minutes at oxygen flow rates of 3, 6, and 10 L/min, respectively, for the large breathing bag and 3.73 minutes at a flow rate of 6 L/min for the small breathing bag. The T1/2 was 8.29, 4.22, and 2.49 minutes at oxygen flow rates of 3, 6, and 10 L/min, respectively, for the large breathing bag and 2.58 minutes for the small breathing bag. CONCLUSIONS AND CLINICAL RELEVANCE: This study emphasizes that there are delays in the rate of increase in the inspired oxygen concentration that accompany use of conventional large animal circle anesthetic systems and low rates of inflow for fresh oxygen.  相似文献   

5.
Nematode eggs were collected by mixing the faeces with a sugar solution, filling a flat-sided medicine bottle (100 ml), and allowing eggs to float and adhere to the upper surface for 30 min. After discarding the faeces, eggs hatched within 24 h at 20-30 degrees C. Each genus was counted in a counting chamber and the L1p.g. estimated. The morphology of L1 of Haemonchus, Teladorsagia, Trichostrongylus, Oesophagostomum and Strongyloides is briefly described.  相似文献   

6.
AIM: To validate the use of para-aminohippuric acid (PAH) as a marker for measuring blood flow in wethers consuming a mixed diet of locoweed and blue grama hay.

METHODS: Fourteen sheep, stratified by bodyweight (BW), were assigned to one of three treatments: 0.8 mg swainsonine (SW)/kg BW (HI), 0.2 mg SW/kg BW (LO), and no SW (Control). Sheep were fed various ratios of locoweed and blue grama hay to deliver SW treatments, for 28 days prior to infusion of PAH. Concentrations of SW and activities of alkaline phosphatase (Alk-P) and aspartate aminotransferase (AST) in serum were measured to confirm exposure to SW and subclinical intoxication. A single 20-ml injection of 5% PAH was delivered into the jugular vein after subclinical intoxication had been achieved. Blood samples were collected and serum analysed for PAH immediately prior to injection, then every 5 min from 5–30 min, and every 10 min from 30–60 min, following injection of PAH.

RESULTS: Effective delivery of SW was evident from the greater concentrations of SW measured in the serum of HI compared with LO animals (p<0.05). No significant differences were detected in the rate of elimination (range 0.097–0.108 L/min), elimination half-life (range 6.62–7.24 min), apparent volume of distribution for the central compartment (range 7.14–9.72 L), and clearance (range 0.73–0.92 L/min) of PAH, between treatments.

CONCLUSIONS: Subclinical intoxication with SW did not affect the pharmacokinetics of PAH. Thus, use of downstream dilution of PAH is a valid method to determine the rate of blood flow in nutrient flux experiments that involve consumption of locoweed.  相似文献   

7.
OBJECTIVE: To examine the accuracy and precision of isoflurane and sevoflurane anesthetic vaporizers. SAMPLE POPULATION: 5 identical isoflurane and 5 identical sevoflurane vaporizers. PROCEDURES: Oxygen flow rates from 0.02 to 10 L/min were used with different vaporizer dial settings. Agent concentrations were measured at the common gas outlet by use of a refractometer. Accuracy was defined as the difference between measured agent concentrations, and dial settings were expressed as a percentage of the applied dial settings. Precision was defined as SD of the measured agent concentrations for each combination of dial setting and flow. RESULTS: Isoflurane values were generally greater than the dial settings. Accuracy of the isoflurane vaporizer was > 20% when 0.6% and 1% was dialed. Accuracy of the sevoflurane vaporizer was always within +/- 20% but decreased at 0.02 L/min flow and at combinations of high flow and high dial settings. Overall precision of the isoflurane vaporizer was better than that of the sevoflurane vaporizer. CONCLUSIONS AND CLINICAL RELEVANCE: A possible explanation for the inaccuracy of the isoflurane vaporizer may be that it was manufactured to be accurate with air but not oxygen, which must be accounted for when using the vaporizer with oxygen, especially with nonrebreathing systems. The sevoflurane vaporizer may not deliver accurate agent concentrations at high flow and high dial settings. Both vaporizers are suitable for clinical use with a wide range of oxygen flow rates if these precautions are properly addressed.  相似文献   

8.
小鼠卵母细胞氯化锶激活条件   总被引:4,自引:0,他引:4  
以昆明小鼠为试验对象,研究了氯化锶(SrCl2)浓度,激尖处理时间以及卵龄对卵母细胞SrCl2孤雌活化的影响。hCG注射后18h的小鼠卵母细胞在1.6,5.0,10,20mmol/L SrCl2的激活液中处理10min,各组间的激活率(原核期卵母细胞的比例)无显著性差异(P>0.05)。10,20mmol/L SrCl2组发育至2-,4-细胞期比率(59.26%,20.37%,63.79%,20.69%)同于1.6,5.0mmol/L 组(20.63%,9.26%,47.06%,7.84)(P<05)。只有20mmol/L组的少数激活卵母细胞(3.45%)发育至桑椹胚阶段。10,20mmol/L SrCl2组处理20,40,60min,2组间的活化率无显著性差异。处理40min,20mmol/L组的桑椹胚和囊胚发育率(64.44%,22.22%)均显著高于10mmol/L组(30.36%,11.61%),处理60min,10mmol/L组的桑椹胚和囊胚发育率(84.68%,46.77%)均显著高于20mmol/L组(67.46%,28.57%),10mmol/L SrCl2处理,20,40,60,180,360min,其活化率和2-细胞的发育率无显著性差异。60,180min处理组的囊胚发育率(49.58%,47.59%)差异不显著,但2者均显著高于20,40,360min组(4.50%,12.24%和35.53%),后3者组间差异显著。随卵龄的增加,活化率显著增加。hCG注射后16h卵母细胞的活化率(77.78%)显著高于14h的卵母细胞(29.63%),而hCG注射后18h卵母细胞的活化率(49.19%)又显著高于16h的卵母细胞,hCG注射后18,20h卵母细胞的活化率差异不显著(94.19%,85.90%)。hCG注射后14,16,18h卵母细胞激活后的囊胚发育率(6.71%,27.78%,47.67%),各组间差异显著。但hCG注射后20h卵母细胞激活后的囊胚发育率(39.74%)显著低于18h的卵母细胞。  相似文献   

9.
Twenty-nine healthy 17- to 29-day-old unweaned Israeli-Friesian male calves were each given a single IV or IM injection of 10 or 20 mg of moxalactam disodium/kg of body weight. Serum concentrations were measured serially during a 12-hour period. Serum concentration vs time profiles were analyzed by use of linear least-squares regression analysis and the statistical moment theory. The elimination half-lives after IV administration were 143.7 +/- 30.2 minutes and 155.5 +/- 10.5 minutes (harmonic mean +/- SD) at dosages of 10 and 20 mg of moxalactam/kg of body weight, respectively. Corresponding mean residence time values were 153.1 +/- 26.8 minutes and 169.9 +/- 19.3 minutes (arithmetic mean +/- SD). Mean residence time values after IM administration were 200.4 +/- 17.5 minutes and 198.4 +/- 19.9 minutes at dosages of 10 and 20 mg/kg, respectively. The volumes of distribution at steady state were 0.285 +/- 0.073 L/kg and 0.313 +/- 0.020 L/kg and total body clearance values were 1.96 +/- 0.69 ml/min/kg and 1.86 +/- 0.18 ml/min/kg after administration of dosages of 10 and 20 mg/kg, respectively. Moxalactam was rapidly absorbed from the IM injection site and peak serum concentrations occurred at 1 hour. The estimated bioavailability ranged from 69.8 to 79.1%. The amount of serum protein binding was 53.4, 55.0, and 61.5% when a concentration of moxalactam was at 50, 10, and 2 micrograms/ml, respectively. The minimal inhibitory concentrations of moxalactam ranged from 0.01 to 0.2 micrograms/ml against Salmonella and Escherichia coli strains and from 0.005 to 6.25 micrograms/ml against Pasteurella multocida strains.  相似文献   

10.
ObjectiveTo describe a technique for ultrasound-guided rectus sheath block in pigs and the distribution of two injectate volumes.Study designExperimental study.AnimalsA group of 11 Hanford miniature pig cadavers.MethodsThe lateral border of each rectus abdominis muscle in 10 freshly euthanized pigs was visualized with a 6-15 MHz linear ultrasound probe. A spinal needle was inserted 1 cm cranial to the umbilicus, in-plane and medial to the probe, and advanced dorsal to lateral until the tip was ventral to the internal rectus sheath. Pigs were injected bilaterally with high volume (treatment HV; 0.8 mL kg–1) or low volume (treatment LV; 0.5 mL kg–1) of 1:1 solution of 1% methylene blue and 0.5% bupivacaine (1 mg kg–1) diluted with 0.9% saline. Nerve staining ≥ 1 cm circumferentially was determined by dissection 15 minutes postinjection. The Clopper–Pearson method was used to calculate 95% confidence intervals (CIs) for proportions of stained nerves. In another pig, a 1:1 solution of 1% methylene blue and 74% ioversol contrast was injected, and computed tomography performed at 15 minute intervals after injection.ResultsNerve staining for thoracic (T) spinal nerves T9, T10, T11, T12, T13 and T14 occurred 20%, 60%, 90% 100%, 100% and 50%, and 0%, 20%, 90%, 100%, 100% and 50% of the time in treatments HV and LV, respectively. More nerves were stained in treatment HV in 4/10 animals (40%, 95% CI: 12%–74%) than in treatment LV (0%, 95% CI: 0%–31%). The greatest spread of injectate occurred within the first 15 minutes after injection.Conclusions and clinical relevanceStaining of T11–T14 nerves was the same in both treatments but the higher volume stained more T9–T10 nerves. Based on dye distribution, a rectus sheath block may only provide ventral abdominal analgesia cranial to the umbilicus in pigs.  相似文献   

11.
Hypothyroidism is associated with impaired blood flow to skeletal muscle under whole body exercise conditions. It is unclear whether poor cardiac and/or vascular function account for blunted muscle blood flow. Our experiment isolated a small group of hindlimb muscles and simulated exercise via tetanic contractions. We hypothesized that muscle blood flow would be attenuated in hypothyroid rats (HYPO) compared with euthyroid rats (EUT). Rats were made hypothyroid by mixing propylthiouracil in their drinking water (2.35 x 10-3 mol/l). Treatment efficacy was evidenced by lower serum T3 concentrations and resting heart rates in HYPO (both P<0.05). In the experimental preparation, isometric contractions of the lower right hindlimb muscles at a rate of 30 tetani/min were induced via sciatic nerve stimulation. Regional blood flows were determined by the radiolabelled microsphere method at three time points: rest, 2 min of contractions and 10 min of contractions. Muscle blood flow generally increased from rest ( approximately 5-10 ml/min per 100 g) through contractions for both groups. Further, blood flow during contractions did not differ between groups for any muscle (eg. red section of gastrocnemius muscle; EUT, 59.9 +/- 14.1; HYPO, 61.1 +/- 15.0; NS between groups). These findings indicate that hypothyroidism does not significantly impair skeletal muscle blood flow when only a small muscle mass is contracting. Our findings suggest that impaired blood flow under whole body exercise is accounted for by inadequate cardiac function rather than abnormal vascular function.  相似文献   

12.
ObjectiveTo evaluate the accuracy of a new cardiac output monitor (FloTrac/Vigileo), originally designed for humans, in dogs. This pulse contour cardiac output monitoring system cannot be calibrated and measures cardiac output (
t) from a standard arterial catheter.Study designProspective experimental trial.AnimalsEight adult Beagle dogs weighing 13.1 (9.8–17.1) kg [median (range)].MethodsAnaesthesia in the dogs was maintained using isoflurane. A pulmonary artery catheter and a metatarsal arterial catheter (22 gauge) were placed. Cardiac output was measured simultaneously 331 times by thermodilution and FloTrac technique. A broad spectrum of
t measurements was achieved through alterations of isoflurane concentration, administration of propofol boluses and dobutamine infusions. Agreement between the methods was quantified with Bland Altman analysis and disagreement was assessed with linear mixed models.ResultsMedian (10th and 90th percentile) cardiac output as measured with thermodilution was 2.54 (1.47 and 5.15) L minute?1 and as measured with FloTrac 8.6 (3.9 and 17.3) L minute?1. FloTrac measurements were consistently higher with a mean bias of 7 L minute?1 and limits of agreement of ?3.15 to 17.17 L minute?1. Difference between the methods was most pronounced in high
t measurements. Linear mixed models showed an estimated difference between the two methods of 8.05 (standard error 1.18) L minute?1 and a significant interaction between mean arterial pressure and method. Standard deviation (4.45 higher) with the FloTrac method compared to thermodilution was increased.ConclusionCompared to thermodilution measurements, the FloTrac system was influenced to a higher degree by arterial blood pressure, resulting in consistent overestimation of cardiac output.Clinical RelevanceThe FloTrac monitor, whose algorithms were developed based on human data, cannot be used as an alternative for thermodilution in dogs.  相似文献   

13.
Haemophilus equigenitalis, the proposed name for the bacterium that causes contaginous equine metritis (CEM) was tested for sensitivity to the disinfectant solutions Nolvasan® (2% chlorhexidine diacetate) and Roccal II® (10 alkyldimethylbenzylammonium chloride).Bacteria (106) suspended in medium were inactivated in 10–20 min at 0°–2°C and in 2.5 min at 20°–22°C by a 3 : 128 dilution of Nolvasan. Roccal II, diluted 1 : 128, inactivated 106 bacteria in 2.5 min at 0°–2°C and 20°–22°C.These dilutions of the disinfectants inactivated H. equigenitalis (titers of 0.1–11.0 × 107/ml) in vaginal exudates from infected mares and pure cultures suspended in medium (titers of 1–5 × 109/ml) in 10 min at 0°–2°C and 20°–22°C when the exudates and cultures were dried on metal carriers. The limit of detection of survivors was 3–32 bacteria/ml.It is recommended that contaminated instruments and other metal surfaces encountered during CEM infections should be decontaminated with either disinfectant for 10 min before rinsing.  相似文献   

14.

Objective

Determine the precorneal retention time of five different ocular lubricants commonly used in dogs.

Animals Studied

Six healthy Beagle dogs (n = 12 eyes).

Procedures

Five ocular lubricants were studied: Artificial Tears Solution® (1.4% polyvinyl alcohol), I-Drop® Vet Plus (0.25% hyaluronate), Optixcare® Eye Lube Plus (0.25% hyaluronate), Systane® Ultra (0.4% polyethylene glycol 400 and 0.3% propylene glycol), and Artificial Tears Ointment® (mineral oil/white petrolatum). Each lubricant was mixed with 10% sodium fluorescein to achieve 1% fluorescein formulations. Following topical administration of 35 mg in each eye, tear fluid was collected with capillary tubes at selected times (0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, 180 min) and fluorescein concentrations were measured with a computerized scanning ocular fluorophotometer.

Results

Tear fluorescence was significantly greater with Artificial Tears Ointment® compared with other lubricant formulations from 1 to 20 min post-administration. Median (range) precorneal retention times were significantly different among the 5 lubricants, ranging from 40 minutes (20–90 min) for Artificial Tears Ointment®, 35 min (20–90 min) for Systane® Ultra, 30 min (10–60 min) for I-Drop® Vet Plus, 25 min (10–60 min) for Optixcare® Eye Lube Plus, and 10 min (10–20 min) for Artificial Tears Solution®. Precorneal retention time was significantly lower for Artificial Tears Solution® compared with the other 4 formulations.

Conclusions

This study established normative data for the retention time of common lubricants on the ocular surface of dogs, which may be used to guide clinicians with their choice of lubricant and frequency of administration.  相似文献   

15.
REASONS FOR PERFORMING STUDY: Guidelines for administration of oxygen to standing horses are unavailable because previous investigations of the efficacy of oxygen administration to increase arterial oxygenation in standing horses have produced equivocal results. OBJECTIVE: To determine the effect of nasal oxygen supplementation on inspired and arterial blood gas tensions in control horses and those with moderate to severe recurrent airway obstruction (RAO). METHODS: Normal horses (n = 6) and horses during an attack of RAO induced by stabling (n = 6) were studied. Oxygen was administered through either one or 2 cannulae, passed via the nares into the nasopharynx to the level of the medial canthus of each eye. Intratracheal inspired oxygen and carbon dioxide concentration and arterial blood gas tensions were measured at baseline and during delivery of 5, 10, 15, 20 and 30 l/min oxygen. RESULTS: Nasal cannulae and all but the highest oxygen flow rates were well tolerated. Fractional inspired oxygen concentration (F(I)O2) increased with flow but was significantly lower at all flow rates in horses with RAO compared with controls. Arterial oxygen tension (PaO2) was significantly increased (P < 0.001) by all flow rates, but was always lower in RAO-affected animals. At 30 l/min, PaO2 increased to 319 +/- 31 mmHg in control horses and 264 +/- 69 mmHg in horses with RAO. Additionally, a large arterial to end-tidal gradient for CO2 in RAO-affected horses was observed, indicating increased alveolar deadspace ventilation in these animals. CONCLUSIONS: The use of nasal cannulae to deliver oxygen effectively increases both F(I)O2 and PaO2 in horses with moderate to severe RAO. Oxygen flow rates up to 20 l/min are well tolerated, but flow rates of 30 l/min produce occasional coughing or gagging. POTENTIAL RELEVANCE: Oxygen therapy delivered by means of an intranasal cannula is a highly effective means of increasing arterial oxygen tension in horses with respiratory disease. Generally, flows of 10-20 l/min should be effective. If higher flows (20-30 l/min) are necessary, they should be delivered by means of 2 cannulae.  相似文献   

16.
OBJECTIVES: To determine agreement of cardiac output measured by use of lithium dilution cardiac output (LiDCO) and thermodilution cardiac output (TDCO) techniques in dogs and to determine agreement of low- and high-dose LiDCO with TDCO. ANIMALS: 10 dogs (7 males, 3 females). PROCEDURE: Cardiac output was measured in anesthetized dogs by use of LiDCO and TDCO techniques. Four rates of cardiac output were induced by occlusion of the caudal vena cava, changes in depth of anesthesia, or administration of dobutamine. Lithium dilution cardiac output was performed, using 2 doses of lithium chloride (low and high dose). Each rate of cardiac output allowed 4 comparisons between LiDCO and TDCO. RESULTS: 160 comparisons were determined of which 68 were excluded. The remaining 92 comparisons had values ranging from 1.10 to 12.80 L/min. Intraclass correlation coefficient (ICC) between low-dose LiDCO and TDCO was 0.9898 and between high-dose LiDCO and TDCO was 0.9896. When all LiDCO determinations were pooled, ICC was 0.9894. For determinations of cardiac output < 5.0 L/min, ICC was 0.9730. Mean +/- SD of the differences of TDCO minus LiDCO for all measurements was -0.084+/-0.465 L/min, and mean of TDCO minus LiDCO for cardiac outputs < 5.0 L/min was -0.002+/-0.245 L/min. CONCLUSIONS AND CLINICAL RELEVANCE: The LiDCO technique is a suitable substitute for TDCO to measure cardiac output in dogs. Use of LiDCO eliminates the need for catheterization of a pulmonary artery and could increase use of cardiac output monitoring, which may improve management of cardiovascularly unstable animals.  相似文献   

17.
The Minimum Alveolar Concentration of Desflurane in Cats   总被引:1,自引:0,他引:1  
Eight adult cats, 4 male and 4 female, (3.5 ± 0.9 [SD] kg) were used to determine the minimum alveolar concentration (MAC) of desflurane. Desflurane (DES) anesthesia was induced in a 20 L chamber with an oxygen inflow of 10 L/min and the DES vaporizer set at 18%. After 3.5 ± 0.5 min, the cats were removed from the chamber and anesthesia was maintained via mask (14% DES, 3L/min O2) until successful intubation. Anesthesia was maintained with DES in oxygen at a flow of at least 200 mL/kg/min through a nonrebreathing circuit. The time from the start of induction to completion of intubation was 6.2 ± 1.1 min. Esophageal temperature was maintained between 37.8°C and 38.6°C. Hand-collected end-tidal gas samples were obtained from a catheter positioned inside the lumen of the endotracheal tube. Inspired and end-tidal DES concentrations were measured with a Biochem 8100 anesthetic agent monitor that was calibrated with known gas standards and modified to accept hand-collected samples. A constant alveolar concentration of DES was maintained for at least 15 minutes, then a clamp was applied to the tail and the cat observed for gross purposeful movement. The end-tidal DES was then increased (if a positive response) or decreased (if a negative response) by 20% and the test repeated after 15 minutes of constant conditions. The final iteration was 10%. The MAC of DES in these cats was 9.79 ± 0.70 vol %. The FA/FI ratio for desflurane was always greater than 0.97.  相似文献   

18.
Two replicates of three multiparous crossbred Large White x Landrace lactating sows were used to develop a technique for the continuous direct measurement of the blood flow through the mammary gland using transit time ultrasound. Four to six days after farrowing, an ultrasonic transit time flow probe was implanted around the right external pudic artery in order to measure the short-term variations of mammary blood flow through this vessel in response to postural change (standing vs lying), meal distribution, hand-milking, and weaning. After surgery, all sows were fed 3.8 kg/d of a lactation diet and housed either at 20 or 28 degrees C. The implantation of the ultrasonic blood flow probe was successful in all six operated sows. Postmortem examination did not indicate the presence of infection, any collateral bypassing the flow probe, or a reduction of artery diameter. The right pudic artery mammary blood flow (PMBF) was measured for 8.5 h over two periods of three days (d 11 to d 13 and d 18 to d 20 of lactation). The PMBF averaged 910 +/- 238 mL/min but was variable within 1 d. Compared with the lying position, PMBF was decreased (- 6%, P < 0.05) when sows were standing. Between 0 to 15 and 16 to 30 min after oxytocin injection (t = 0) and hand-milking, PMBF remained constant (P = 0.05; 801 vs 767 mL/ min) and increased (P = 0.02), respectively, in comparison with the mean calculated over the preceding 30-min period (982 vs 784 mL/min). The PMBF increased (P < 0.05) after meal distribution and reached a peak 65 min later (i.e., 980 mL/min). The PMBF decreased regularly after separation of piglets at weaning; at 8 and 16 h after weaning, PMBF was 60 and 40% of the value recorded before weaning, respectively. Assuming that PMBF drains one-quarter of the whole mammary gland, it can be calculated that blood flow through the entire mammary gland averages 3.6 L/min and that about 470 L of blood are required to produce 1 kg of milk. The proposed methodology constitutes a new technique to measure direct mammary blood flow and its short-term factors of variation.  相似文献   

19.
Eleven buffalo calves (Bubalus bubalis) of 1-1 1/2 years of age and weighing between 64 and 174 kg were given chloramphenicol at the dose rates of 10 and 20 mg/kg body weight. Pharmacokinetic parameters were determined from the plasma levels. The median elimination half-life was estimated to be 2.95 h and the median volumes of distribution were 1.1667 litres/kg with the 10 mg/kg dose and 0.9699 litres/kg with the 20 mg/kg dose. The median metabolic clearance rates were 288.30 and 234.13 ml/h/kg, respectively. From the average plasma concentrations obtained with the 20 mg/kg i.v. dose, it was considered necessary to repeat the drug by the i.m. route with the same dose (four calves) which resulted in prolonging the therapeutic concentration (> 5 μg/ml) until 18 h. At therapeutic concentrations, about 60% of the drug was bound to plasma proteins. Using the overall elimination rate constant (0.2354 h-1) and the apparent specific volume of distribution (0.97 litres/kg), different dosage regimens were calculated so as to obtain plasma concentrations (Cp min) of 2, 5 and 10 μg/ml.  相似文献   

20.
The aim of this study was to investigate the effects of different vitrification solutions [EFS30 or EFS40 contains 30% (v/v) ethylene glycol (EG), 40% (v/v) EG; EDFS30 or EDFS40 contains 15% (v/v) EG and 15% (v/v) dimethyl sulfoxide (DMSO), 20% (v/v) EG and 20% (v/v) DMSO], equilibrium time during vitrification (0.5-2.5 min) and vitrification protocols [one-step straw, two-step straw and open-pulled straw (OPS)] on in vivo development of vitrified Boer goat morulae and blastocysts after embryo transfer. In the one-step straw method, the lambing rates of vitrified embryos in EFS30 (37.5%), EFS40 (40.5%) or EDFS30 (38.2%) group were similar to that of fresh embryos (57.5%) and conventional freezing method (46.7%) when the equilibrium time was 2 min. In the two-step straw method, the highest lambing rate was obtained when embryos were pretreated with 10% EG for 5 min and then exposed to EFS40 for 2 min (51.4%), showing similar lambing rates compared with fresh embryos (56.1%) or the embryos cryopreserved by conventional freezing method (45.2%). In the OPS method, the lambing rate in EFS40, EDFS30 or EDFS40 groups were similar to that (57.1%) of fresh embryos, or to that (46.0%) of embryos cryopreserved by conventional freezing method. The highest lambing rate (51.4%) of the group of OPS was obtained when the embryos were vitrified with EDFS30. In conclusion, either the two-step straw method in which embryos were pretreated in 10% EG for 5 min and then exposed to EFS40 for 2 min, or the OPS method in which embryos were pretreated in 10% EG + 10% DMSO for 30 s and then exposed to EDFS30 for 25 s was a simple and efficient method for the vitrification of Boer goat morulae and blastocysts.  相似文献   

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