K. Olsson

Relationship between different natriuretic peptides and severity of naturally acquired mitral regurgitation in dogs with chronic myxomatous valve disease.

OBJECTIVE To study the responses of atrial natriuretic peptide (ANP), N-terminal fragment of pro-atrial natriuretic peptide (NT-proANP) and brain natriuretic peptide (BNP) to varying severity of mitral regurgitation (MR) in dogs with myxomatous valve disease (MVD). DESIGN Case-control. DOGS: 103 Cavalier King Charles Spaniels, 27 normal individuals and 76 with varying degree of MR. PROCEDURE Dogs were evaluated by physical examination, collection of venous blood, thoracic radiography and echocardiography. NT-proANP, ANP and BNP were measured in plasma using radio immunoassay (RIA). RESULTS The mean concentrations of NT-proANP were 37.4 and 83.5 times higher than ANP and BNP, respectively. The mean ANP to BNP molar ratio was 2.6. Plasma concentrations of NT-proANP and ANP were slightly increased in asymptomatic dogs with increased cardiac dimensions; those with signs of decompensated heart failure (HF) had mean concentrations of NT-proANP and ANP 3 to 7 times higher than normal dogs. The BNP concentrations were increased only in dogs with decompensated HF and the levels were approximately twice as high in these dogs as in normal individuals. Univariate and multiple regression analysis showed that primarily left atrial and ventricular size influenced the plasma concentrations of all 3 peptides (increased with increasing measurement). Analyses of response operating characteristic (ROC) curves indicated that NT-proANP and ANP were more discriminating than BNP for either cardiomegaly of HF. CLINICAL IMPLICATIONS Natriuretic peptides, particularly NT-proANP and ANP, may be of benefit in the overall assessment of dogs with naturally occurring MR. Analysis of NT-proANP may be more useful than ANP owing to easier handling of the samples and less laborious assay.

Clinical pharmacology of methadone in dogs

OBJECTIVE To investigate the pharmacokinetics and effects of methadone on behaviour and plasma concentrations of cortisol and vasopressin in healthy dogs. STUDY DESIGN Randomized, cross-over, experimental trial. ANIMALS Nine adult dogs (beagle and beagle cross breeds), four males and five females. METHODS Methadone hydrochloride, 0.4 mg kg(-1), was administered intravenously (IV) and subcutaneously (SC) with a crossover design. Drug and hormone analyses in plasma were performed using Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry and radioimmunoassay respectively. Behavioural data were collected using a standardized protocol. RESULTS After IV administration, the plasma concentration of methadone at 10 minutes was 82.1 +/- 9.2 ng mL(-1) (mean +/- SD), the terminal half-life was 3.9 +/- 1.0 hours, the volume of distribution 9.2 +/- 3.3 L kg(-1) and plasma clearance 27.9 +/- 7.6 mL minute(-1) kg(-1). After SC administration, time to maximal plasma concentration was 1.26 +/- 1.04 hours and maximal plasma concentration of methadone was 23.9 +/- 14.4 ng mL(-1), the terminal half-life was 10.7 +/- 4.3 hours and bioavailability was 79 +/- 22%. Concentrations of both cortisol and vasopressin were increased for an hour following IV methadone. The observed behavioural effects of methadone were decreased licking and swallowing and an increase in whining after SC administration. The latter finding is notable as it can be misinterpreted as pain when methadone is used as an analgesic. CONCLUSION AND CLINICAL RELEVANCE When methadone was administered by the SC route, the half-life was longer, but the individual variation in plasma concentrations was greater compared with IV administration. Increased frequency of whining occurred after administration of methadone and may be a drug effect and not a sign of pain. Cortisol and vasopressin concentrations in plasma may not be suitable for evaluating analgesia after methadone treatment.

Pharmacokinetics of meloxicam in adult goats and its analgesic effect in disbudded kids

The pharmacokinetics and analgesic effect of the nonsteroidal anti-inflammatory drug meloxicam (0.5 mg/kg) in goats were investigated. In a randomized, cross-over design the pharmacokinetic parameters were investigated in adult goats (n = 8) after single intravenous and oral administration. The analgesic effect was evaluated in kids using a randomized, placebo controlled and blinded protocol. Kids received meloxicam (n = 6) once daily and their siblings (n = 5) got isotonic NaCl intramuscularly while still anaesthetized after cautery disbudding and injections were repeated on three consecutive days. In the adult goats after intravenous administration the terminal half-life was 10.9 ± 1.7 h, steady-state volume of distribution was 0.245 ± 0.06 L/kg, and total body clearance was 17.9 ± 4.3 mL/h/kg. After oral administration bioavailability was 79 ± 19%, C(max) was 736 ± 184 ng/mL, T(max) was 15 ±5 h, although the terminal half-life was similar to the intravenous value, 11.8 ± 1.7 h. Signs of pain using a visual analogue scale were smaller in kids treated with meloxicam compared with kids treated with placebo on the first day after disbudding, but subsequently no difference in pain was noticeable. Plasma cortisol and glucose concentrations did not differ between the two groups.

A Serial Study of Heart Function During Pregnancy, Lactation and the Dry Period in Dairy Goats Using Echocardiography

Echocardiography and Doppler measurements were performed to investigate changes in heart dimensions and function during pregnancy, lactation and the non‐pregnant, non‐lactating (dry) period in dairy goats. Eight Swedish domestic goats (Capra hircus) were studied with two‐dimensional (2DE), M‐mode and continuous wave Doppler measurements. Cardiac dimensions did not differ between periods. The mean cardiac outputs were 35 and 28% greater during pregnancy and lactation, respectively, vs. the dry period. Arterial blood pressure (measured by telemetry) did not differ between reproductive periods before echocardiographic measurements, but became elevated during the measurements, with the smallest rise during lactation. Heart rate was elevated during pregnancy and increased further during echocardiographic measurements, but was not elevated during the other periods. The cranial location of the heart influenced the selection of examination window and caused some difficulties in positioning the ultrasound transducer. This may have led to underestimation of the velocity trace integral and therefore to underestimation of cardiac output. However, our values were within the range of these obtained with dye‐ and thermodilution methods. The goats tolerated the investigations well during lactation and the dry period, but showed increased blood pressure and heart rate during pregnancy. Therefore, the non‐invasive and safe echocardiographic‐Doppler method appears to be a good alternative for studies of heart dimensions and function during lactation and the dry period in the dairy goat.

Plasma vasopressin, oxytocin, estradiol, and progesterone related to water and sodium excretion in normal pregnancy and gestational hypertension

Objective. To investigate associations between plasma oxytocin and vasopressin concentrations and renal water and sodium excretion during normal pregnancy in comparison with gestational hypertension. Design. A prospective open trial conducted in the 12th, 24th, and 36th weeks of gestation. Settings. Seven antenatal clinics in Sweden. Participants. Thirty‐seven normotensive women, 15 women with gestational hypertension, and five women with mild preeclampsia. Main outcome measures. Hormones were analyzed with radioimmunoassay. Albumin, osmolality, sodium, and urea were analyzed by routine methods. Results. Blood pressure was elevated in the hypertensive women and body mass index in mild preeclampsia from week 12. Renal sodium excretion did not differ between groups or weeks and mean renal free water clearance was negative. In normotensive women, the vasopressin concentration was 1.1±0.2 (week 12) and 0.7±0.1 pmol/L (week 36: p = 0.053). In hypertensive women, vasopressin concentration was 1.7±1.0 pmol/L, week 12, and 0.7±0.1 pmol/L in week 36 (ns). In normotensive women, oxytocin concentration increased from 23±1 pmol/L in week 12 to 48±3 pmol/L in week 36 (p<0.001). Corresponding values in hypertensive women were 36±11 (week 12) and 55±5 pmol/L (week 36: ns). In all groups, plasma estradiol concentration increased. Plasma progesterone increased until week 24 in normotensive and hypertensive women with further increase in normotensive women. Conclusions. The low plasma vasopressin and increasing plasma oxytocin concentrations with unchanged water and sodium excretion indicate that oxytocin assists vasopressin in concentrating urine during pregnancy.

Paranoid potato: phytophthora-resistant genotype shows constitutively activated defense.

Phytophthora is the most devastating pathogen of dicot plants. There is a need for resistance sources with different modes of action to counteract the fast evolution of this pathogen. In order to better understand mechanisms of defense against P. infestans, we analyzed several clones of potato. Two of the genotypes tested, Sarpo Mira and SW93-1015, exhibited strong resistance against P. infestans in field trials, whole plant assays and detached leaf assays. The resistant genotypes developed different sizes of hypersensitive response (HR)-related lesions. HR lesions in SW93-1015 were restricted to very small areas, whereas those in Sarpo Mira were similar to those in Solanum demissum, the main source of classical resistance genes. SW93-1015 can be characterized as a cpr (constitutive expressor of PR genes) genotype without spontaneous microscopic or macroscopic HR lesions. This is indicated by constitutive hydrogen peroxide (H2O2) production and PR1 (pathogenesis-related protein 1) secretion. SW93-1015 is one of the first plants identified as having classical protein-based induced defense expressed constitutively without any obvious metabolic costs or spontaneous cell death lesions.

Relationship between urinary albumin and albumin/creatinine ratio during normal pregnancy and pre-eclampsia.

Risberg A, Larsson A, Olsson K, Lyrenäs S, Sjöquist M. Relationship between urinary albumin and albumin/creatinine ratio during normal pregnancy and preeclampsia. 2004; 64: 17-24. Pre-eclampsia is a serious complication of pregnancy and it is important to detect the condition as early as possible. Albuminuria is an important symptom of pre-eclampsia and repeated urine analyses to screen for the condition are part of the standard antenatal care. The purpose of this study was to investigate whether measurement of the urine albumin/creatinine ratio in spot samples could be a complement to the dipstick method and could reduce the need for 24-h urine collections. Urine samples were collected for 24 h in weeks 12, 24 and 36 of pregnancy from both normotensive women and women who developed hypertension or who had pregnancy-induced hypertension (PIH) when they entered the study. The 24-h albumin excretion was significantly correlated to the albumin/creatinine ratio in all measurements (Pearson correlation coefficient). In week 12, the values were: n = 44, r = 0.964, p<0.001 (normotensive group) and in the PIH group: n = 8, r = 0.789, p<0.05. In week 24, the correlation values were r = 1.0 and p<0.001 in both the normotensive group (n = 41) and in the PiH group (n= 11). In week 36 the correlation values were r = 0.791 and p<0.00l in the normotensive group (n = 39) and r= 1.0 and p<0.001 in the PIH group (n= 16). Microalbuminuria was denned as urine albumin excretion higher than 30 mg/24 h and this corresponded to an albumin/creatinine ratio of 2.9. Microalbuminuria was found in three persons in the PIH group and in two persons in the normotensive group. Overt albuminuria (> 300 mg/24 h) was found in one of the 46 normotensive women (2%) and in 3 of the 19 PIH women (16%). In all these women the high albumin values had been detected by using the albumin/creatinine ratio method. In conclusion, it has been found that the albumin excretion in urine correlates significantly to the albumin/creatinine ratio during pregnancy. The urinary albumin/creatinine ratio appears to be a good alternative to the dipstick method and to 24-h urine collections.

Mechanisms of water economy in lactating Ethiopian Somali goats during repeated cycles of intermittent watering.

We investigated the physiological and behavioural strategies by which lactating Ethiopian Somali goats endure repeated periods of water deprivation. The experiment lasted for 32 days and was divided into four periods of 8 days each. Measurements were taken during the first 4 days in each period. Seven does (W1) were watered once daily and seven does (W4) were watered once every 4th day. Rectal temperature was taken at 0800 and 1715 h. Blood samples were taken in the evening and milk samples in the morning. The goats were on pasture between 0900 to 1215 h and 1315 to 1630 h with behaviour recorded every 5 min. The does were supplemented with 300 g of concentrates per head per day. Plasma and milk osmolality were determined by freezing point depression. Plasma total protein was measured on a TS refractometer. Plasma vasopressin concentrations were analysed by radio-immunoassay. The mean daily water intake of W1 was 1897 ml compared with the calculated mean of 1075 ml in W4 (P < 0.001). The mean diurnal variation of the rectal temperature was 3.5°C in both groups. Afternoon rectal temperature in W4 during period 1 was higher than that in the W1 on the days of water deprivation (P < 0.05). With repeated periods, plasma osmolality in W4 increased less over the days of water deprivation. It was 336, 321, 311 and 306 mosm/l on the 4th day at periods 1, 2, 3 and 4, respectively. The corresponding vasopressin concentrations were 10.0, 9.2, 4.2 and 4.4 pmol/l. Total plasma protein concentration during period 1 on days 3 and 4 were higher in W4 than in W1 (P < 0.01). During the subsequent periods, it did not increase more in W4 compared with W1, but it was lower in W4 on the days after watering. W4 milk production decreased by 22% compared with W1 in all periods. With increasing days of water deprivation, the W4 goats spent less time in the sun, grazed shorter time and frequently ate cactus (Opuntia ficus-indica) as compared with W1. Results suggested that dehydrated lactating Ethiopian Somali goats economised on water by diurnal variations of rectal temperature, storing water in the extracellular fluid, by changing behaviour at grazing and by decreasing milk production.

Comparison of haemodynamic changes during two surgical methods for neutering female dogs.

The aim was to investigate if intraoperative registrations of blood pressure and heart rate could be used to estimate surgical trauma. In a prospective clinical trial, registrations in eight dogs neutered by laparoscopic ovariectomy (LOE) were compared with eight dogs subjected to open ovariohysterectomy (OHE). For comparisons phases were used: phase zero=steady state after induction of anaesthesia; phase one=opening of abdomen; phase two=severing of ovarian pedicles; and, phase three=abdominal closure. During LOE, mean systolic blood pressure increased by 7 mmHg (p=0.05) and 15 mmHg (p=0.01) from phase zero to phase one and two, respectively, and during OHE by 3 mmHg (ns) and 29 mmHg (p<0.0001), respectively. The increase from phase one to phase two differed between groups (p=0.03). Heart rate did not change. Frequent intraoperative measurements of blood pressure appear a promising method for evaluating surgical trauma.

Temperature regulation in horses during exercise and recovery in a cool environment

BackgroundClipping the winter coat in horses is done to improve heat dissipation during exercise and make grooming easier. It is often combined with blanketing to keep the horse warm. The aims of the present study were to investigate how clipping and the use of blankets affect thermoregulation during exercise and recovery in horses.MethodsOne Gotland pony, one New Forest pony, and one warm-blooded horse exercised one after the other on a 6450 m long track. The horses walked, trotted and cantered according to a predetermined scheme, which took about 50 minutes including three stops. The scheme was repeated on five consecutive days when horses were: 1) unclipped 2) unclipped + blanket during recovery, 3) left or right side clipped, 4) clipped, and 5) clipped + riding blanket + blanket during recovery. Heart rate (HR) was measured with telemetry, respiratory rate (RR) by counting flank contractions, skin temperatures by thermistor probes, and rectal temperature with a digital thermometer. Skin wetness (SW) was estimated by ocular inspection (dripping = 5, dry = 0).ResultsMean outdoor temperature varied from -1.1 to - 8.7°C. HR increased progressively during exercise with no difference between treatments. Maximum RR was 77 ± 30 breaths/min (unclipped) and 49 ± 27 breaths/min (clipped). The lowest skin temperature was 17.5 ± 2.7°C in a hind leg during exercise, which increased to 34.5 ± 0.1°C during recovery. Rectal temperature was elevated during recovery in unclipped, but not in clipped horses and skin temperature at base of tail was elevated during recovery except in unclipped horses without blanket. Moisture after exercise scored 3.2 ± 0.8 in unclipped and zero in clipped horses.Discussion and conclusionLeg skin temperature initially dropped at onset of exercise in clipped horses, and then increased after about 30 minutes due to internal heat from the working muscles. These changes were not significant when clipped horses had riding blankets, whereas unclipped horses became overheated as judged from respiratory rate and elevated rectal temperature. Providing clipped horses with blankets dampened the changes in leg skin temperature during exercise.