Thyroid evaluation in suspicious hypothyroid adult dogs before and after treatment.

The purpose of this study was to measure circulating TSH, T4 and fT4 concentrations in dogs submitted to a clinical visit for general symptoms (weight gain, polyuria and polydipsia, changes in hair coat). Twenty-eight dogs, 14 cross-breed and 14 purebreds (Golden Retriever, Labrador, Doberman), of both sexes (14 males and 14 females), aged 8 to 14 years, were assessed. No significant differences of circulating TSH, T4 , fT4 concentrations between the baseline and after therapeutic treatment nor between intact and neutered females were observed. Compared to baseline values, intact males showed higher TSH concentrations (p⟨0.01), and castrated males lower TSH concentrations (p⟨0.01) after therapeutic treatment. Compared to intact males, castrated males showed baseline TSH concentrations higher (p⟨0.01), but lower (p⟨0.01) after therapeutic treatment. No significant differences of T4 and fT4 concentrations between baseline conditions and after therapeutic treatment, nor between intact and castrated males, were observed. The experimental sample considered in this study falls within that casuistry involving elevated TSH concentrations but low serum T4 and fT4 concentrations or close to the minimum physiological cut-off, in which the common clinical signs suggestive of hypothyroidism was, essentially, overweight and neglected appearance of the hair.

Temporal relationships of GH, IGF-I and fructosamine concentrations in pregnant Spanish Purebred mares: A substantial contribution from the hormonal standpoint.

Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares, with an age range of 9.33 ±â€¯3.31 years, were studied during the 11 months of gestation. Serum concentrations of GH, IGF-I and FRUCT were analyzed by EIA, competition ELISA and spectrophotometry, respectively. GH showed a biphasic pattern, the first occurred during 4th and 5th month and the second which was higher than the 1st one during the 7th, 8th and 9th month (P < 0.05). Compared to the 1st month, the IGF-I concentrations increased in the 2nd month (P < 0.05), decreased in the 3rd and 4th month and increased to reach the maximum average value in the 5th month (P < 0.05); after slight oscillations between the 6th and 8th month, IGF-I concentrations increased in the 9th month (P < 0.05), decreasing until the end of gestation. FRUCT increased progressively and significantly from the 6th month of gestation, reaching the maximum values in the last month of gestation (P < 0.05). These results suggest that alternative mechanisms other than GH and IGF-I could be involved in the regulation of glycaemic metabolism in pregnant mare.

Sequential concentrations of placental growth factor and haptoglobin, and their relation to oestrone sulphate and progesterone in pregnant Spanish Purebred mare.

The objectives of this study were to establish reference values for serum concentrations of placental growth factor (PlGF) and haptoglobin (Hp), and to analyze whether the levels of oestrone sulphate (E1S) and progesterone (P4) are physiologically involved in the dynamic modifications of the above parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares ranging in age 9.33 ±â€¯3.31 years were studied during the 11 months of gestation. Serum concentrations of PlGF were detected by EIA, Hp using commercial Phase Haptoglobin assay and E1S and P4 levels through RIA. The serum concentrations of PlGF ranged between 31.70 and 223.60 ng/mL, with a mean value of 57.64 ±â€¯18.05 ng/mL. Serum PlGF levels increased significantly during the 1st and 2nd months, reaching the maximum value in the 3rd month and the minimum value in the 10th month. Hp concentrations increased progressively and significantly from the 5th until the 10th month of gestation (P < 0.05), decreasing in the 11th month of pregnancy. E1S increased significantly from the 3rd until the 7th month, decreasing progressively towards the end of gestation. P4 increased significantly in the 3rd and 4th month and decreased significantly in the 6th and 7th (P < 0.05), with variable oscillations during last months of pregnancy. PlGF and Hp were significantly and negatively correlated (r = -0.27; P < 0.05). In the healthy mare, PlGF and Hp act asynchronously and independent of steroid E1S and P4.

Influence of training and competitive sessions on peripheral ß-endorphin levels in training show jumping horses.

AIM: To investigate the effects of training sessions on circulating ß-endorphin changes in sport horses before and after competition and to ascertain whether competition would affect this response. MATERIALS AND METHODS: A total of 24 trained jumping horses were randomly assigned to one of two training groups: Group A (competing) and Group B (not competing). To determined plasma ß-endorphin concentrations, two pre- and post-competition training weeks at aerobic workout and two competitive show jumping event days at anaerobic workout were measured before, 5 and 30 min after exercise. Exercise intensity is described using lactate concentrations and heart rate. The circuit design, intensity, and duration of training sessions were the same for both groups. RESULTS: In Group A, one-way analysis of variance for repeated measures (RM-ANOVA) showed significant effects of exercise on ß-endorphin changes (F=14.41; p<0.001), only in the post-competition training sessions, while in Group B showed no significant effects. Two-way RM-ANOVA showed, after post-competition training sessions, a significant difference between Group A and Group B (F=6.235; p=0.023), with higher ß-endorphin changes in Group A, compared to Group B. During the competitive show jumping sessions, one-way RM ANOVA showed significant effects of exercise on ß-endorphin changes (F=51.10; p<0.001). The statistical analysis, in Group A, showed a significant difference between post-competition training and competitive exercise (F=6.32; p=0.024) with higher ß-endorphin values in competitive sessions compared to those of post-competition training. CONCLUSION: Lactate concentrations seem to be the main factors being correlated with the raise of ß-endorphin during anaerobic exercise of competitive events. Exercise of low intensity, as well as that one of training sessions, does not appear to stimulate a significant increased release of ß-endorphin and it may depend on the duration of the exercise program. Moreover, the responses during exercise in the course of post-competition training sessions seem to be significantly different from those the pre-competition training. These data show that the preliminary competitive stress induced additional significant changes of ß-endorphin pattern. It would reflect the need of a long-lasting modulation of fatigue and pain perception related to the effect of an additional physical and mental effort for the consecutive competitive and training sessions.

The stress response of Ragusano donkey (Equus asinus) to different semen collection techniques.

The aim of the present study was to characterize the stress response of donkeys to different semen collection techniques, comparing the physiological patterns of hormonal (adrenocorticotropic hormone: ACTH, cortisol) and biochemical variables (creatinine, total protein, urea, aspartate aminotransferase: AST, alanine aminotransferase: ALT), and routine seminal parameters and sexual behaviour. Twenty two healthy Ragusano donkeys were used and were randomly assigned to one of 2 groups based on different semen collection techniques. Group A was designated as the experimental group and included 16 donkeys submitted to semen collection by an artificial vagina (AV) "on the ground"; group B was designated as the control group, and included 6 donkeys submitted to semen collection by AV during the mount. The semen collection was performed in October, once a day for 10 consecutive days. Blood samples were collected in baseline conditions, before the onset of the treatments and within 30 min after, from the jugular vein of each subject. Two-way ANOVA showed a significant effect of semen collection technique and time points in group A for ACTH (p=0.0084), cortisol (p=0.0004) and creatinine (p=0.0131), with lower values after semen collection than before. A significant effect of semen collection technique and time points in group B for ACTH (p<0.0001) and cortisol (p<0.0001) was observed, with higher values after semen collection than before. The comparison between groups A and B values over different time points showed a significant effect after semen collection for ACTH (p<0.0001), cortisol (p<0.0001) and creatinine (p<0.0001), with the highest values in group B. This study provides the physiological evidence that semen collection on the ground in healthy donkeys could be used as an alternative strategy to induce a positive animal approach and economical advantages.

Pituitary-adrenocortical adjustments to transport stress in horses with previous different handling and transport conditions.

AIM: The changes of the hypothalamic pituitary adrenal (HPA) axis response to a long distance transportation results in increase of adrenocorticotropic hormone (ACTH) and cortisol levels. The purpose of the study was to quantify the level of short-term road transport stress on circulating ACTH and cortisol concentrations, related to the effect of previous handling and transport experience of horses. MATERIALS AND METHODS: The study was performed on 56 healthy horses after short-term road transport of 30 km. The horses were divided into four groups, Groups A, B, C, and D, with respect to the handling quality: Good (Groups A and B), bad (Group D), and minimal handling (Group C) conditions. According to the previous transport, experience horses were divided as follows: Horses of Groups A and D had been experienced long-distance transportation before; horses of Groups B and C had been limited experience of transportation. RESULTS: One-way RM-ANOVA showed significant effects of transport on ACTH changes in Groups B and C and on cortisol changes in both Groups A and B. Groups A and B showed lower baseline ACTH and cortisol values than Groups C and D; Groups A and B showed lower post-transport ACTH values than Groups C and D. Groups A, B, and C showed lower post-transport cortisol values than Group D. Only Groups A and B horses have shown an adequate capacity of stress response to transportation. CONCLUSION: The previous transport experience and quality of handling could influence the HPA axis physiological responses of horses after short-term road transport.

The outcome of the first stages of pregnancy on mares' bloodstream thyroid hormones.

The objective of this study was to compare in detail the total and free iodothyronines' pattern of mares from the first ovulation of the year over an extended period of 12 weeks. A total of 20 mares were used in the study. The mares were classified into two groups: mares mated at the ovulation (n = 10) used as observational group and mares unmated at the ovulation (n = 10) used as control group. Serum total and free triiodothyronine (T3, fT3) and thyroxine (T4, fT4) levels were measured in baseline conditions at the first ovulation of year and once a week until 12 weeks later. For the experimental group, the first week of postovulation mating was considered as the first week of gestation. One-way analysis of variance showed a significant effect of time over 12 weeks for T3 (F = 2.44; P = 0.007) in pregnant mares, with the higher levels at the seventh and 12th weeks (P < 0.05) than baseline values, and for fT3 (F = 2.36; P = 0.009), with the higher levels at the 11th week (P < 0.05) than baseline values. Two-way analysis of variance showed a significant pregnancy effect compared with nonpregnancy stage for T3 (F = 15.82; P = 0.009), with the higher levels at the seventh and 12th weeks (P < 0.05) of pregnancy than that in nonpregnant values. Thus, it appears that, under similar environment, management and nutritional regime, the first trimester of pregnancy plays a dynamic role on the thyroid patterns by their anabolic activity; therefore, significant effects of time points on the T3 and fT3 concentrations probably may contribute to the control of early embryonic growth and development, before the onset of fetal thyroid activity. Considerable additional research, outwith the aim of this study, will be required to elucidate the mechanisms by which gestational age affects the physiological thyroid function in mares and/or fetus ratio in the first pregnancy stage.

Effects of weaning on total and free iodothyronines in lambs.

BACKGROUND: Weaning is a crucial period in the management of lambs, resulting in physiological and mental challenges, that may have prolonged effects on lamb's health and welfare. HYPOTHESIS/OBJECTIVES: To evaluate the effect of weaning on total and free triiodothyronine (T3, fT3) and thyroxine (T4, fT4) concentrations in serum of lambs by enzyme immunoassay. Animal and methods: The study was performed on two groups of 17 clinically healthy Comisana cross-bred lambs (7 males and 10 females) with or without weaning at 10 weeks of age. Serum samples were collected at the age of 8 weeks, 24 h and 2 weeks after weaning in the experimental group and at similar times in the non-weaned control group. Enzyme immunoassay was performed. Statistical analysis was done by one-way analysis of variance. RESULTS: Compared to control animals, weaned animals showed significantly decreased T3 and elevated T4 concentrations two weeks after weaning with higher concentrations in both males and females in contrast to 24 h after weaning. Body weight (BW) was significantly restored in both females (11% increase) and males (6%) two weeks after weaning as compared to 24 h after weaning. No gender effects were shown for total and free iodothyronine changes. Significant positive correlations were observed between BW and T4 concentrations in both females (r = 0.692) and males (r = 0.856), fT3 concentrations in males (r = 0.968) and fT4 concentrations in females (r = 0.862). CONCLUSION AND CLINICAL IMPORTANCE: Total iodothyronines could represent an indicator of their different metabolic activity with their magnitude altered two weeks following weaning.

Release of ß-endorphin, adrenocorticotropic hormone and cortisol in response to machine milking of dairy cows.

AIM: The present study was undertaken with the objective to obtain insight into the dynamics of the release of ß-endorphin, adrenocorticotrophic hormone (ACTH) and cortisol in response to machine milking in dairy cows. MATERIALS AND METHODS: A total of 10 healthy multiparous lactating Italian Friesian dairy cows were used in the study. Animals were at the 4(th)-5(th) month of pregnancy and were submitted to machine milking 2 times daily. Blood samples were collected in the morning: In baseline conditions, immediately before milking and after milking; and in the early afternoon: In baseline conditions, before milking and after milking, for 2 consecutive days. Endocrine variables were measured in duplicate, using a commercial radioimmunoassay for circulating ß-endorphin and ACTH concentrations and a competitive enzyme-linked immunoassay for cortisol concentration. RESULTS: Data obtained showed a similar biphasic cortisol secretion of lactating dairy cows, with a significant increase of cortisol concentration after morning machine milking, at both the 1(st) and the 2(nd) day (p<0.05), and a decrease after afternoon machine milking at the 2(nd) day (p<0.01). One-way RM ANOVA showed significant effects of the machine milking on the cortisol changes, at both morning (f=22.96; p<0.001) and afternoon (f=15.10; p<0.01) milking, respectively. Two-way RM ANOVA showed a significant interaction between cortisol changes at the 1(st) and the 2(nd) day (f=7.94; p<0.0002), and between the sampling times (f=6.09; p<0.001). Conversely, no significant effects of the machine milking were observed on ß-endorphin and ACTH changes, but only a moderate positive correlation (r=0.94; p<0.06) after milking stimuli. CONCLUSIONS: A wide range of cortisol concentrations reported in this study showed the complex dynamic patterns of the homeostatic mechanisms involved during machine milking in dairy cows, suggesting that ß-endorphin and ACTH were not the main factors that caused the adrenocortical response to milking stimuli.

Effect of temperament and prolonged transportation on endocrine and functional variables in young beef bulls.

The purpose of this study was to evaluate the effect of prolonged transportation on adrenocorticotropic hormone (ACTH), cortisol, total and free triiodothyronine (T(3), fT(3)) and thyroxine (T(4), fT(4)) concentrations, and functional variables (heart rate (HR), respiratory rate (RR) and rectal temperature (RT)) in calm and temperamental Limousin young beef bulls. Exit velocity measurement was used to classify bulls' temperament as calm (group I: consisted of eight slowest bulls) and temperamental (group II: consisted of five fastest bulls). Calm subjects showed an increase of ACTH (P<0.05) and T(4) (P<0.01) concentrations after transportation compared with before transportation values. Temperamental subjects showed higher ACTH (P<0.01) concentrations before transportation, and lower T(4) (P<0.05) and fT(4) (P<0.001) concentrations after transportation than calm subjects. Related to functional variables, temperamental young beef bulls showed a decrease of RT (P<0.05) after transportation compared with before values, higher RT (P<0.001) before transportation, and higher HR (P<0.001) and RR (P<0.01) after transportation than calm subjects. Data obtained suggest that longer periods of transportation could minimise the magnitude and duration of the endocrine and functional responses to stress of young beef bulls; such responses probably decrease or disappear during transport, in accordance with animal temperament.

Influence of endemic goitre areas on thyroid hormones in horses.

The aim of this study was to investigate thyroid hormone levels in horses stabled in two different locations on the island of Sicily. The study was carried out on a total of 72 clinically healthy Sanfratellano horses ranging in age from 5 to 9 years and weighing 585 ± 40 kg. The results showed higher thyroxine values (P < 0.02) in horses stabled in an endemic goitre area (group II) than those observed in horses in a non-endemic area (group I). Unexpectedly, the T(4)/T(3) and the fT(4)/fT(3) rations were both lower in group I than in group II. The percentages of fT(4) to T(4) and of fT(3) to T(3) were both higher in group I than the percentages for group II. On the basis of gender, comparison between the two groups showed higher T(4) (P < 0.01) and fT(4) levels (P < 0.001) in males, and lower fT(3) (P < 0.001) and fT(4) levels (P < 0.005) in females stabled in the goitre endemic area. On the basis of age, younger horses (<7 years old) showed the highest thyroid hormone levels in both groups. Results suggest a physiological adaptive response of the equine species to an endemic goitre environment. The possibility that hypothyroidism is present in these horses is thus excluded and is supported not only by the lack of clinical signs, but also by the rarity of cases previously reported.

Effects of fence height on total and free iodothyronine changes in horses after experimental show jumping sessions.

REASONS FOR PERFORMING STUDY: Involvement of thyroid function on performance warrants further investigation as limited data exists on the effects of showjumping on the dynamics of total and free iodothyronines. OBJECTIVES: To investigate the response of circulating total and free iodothyronines in horses to experimental showjumping sessions and compare with the effects normally induced by competition and determine if fence height has any effect. MATERIALS AND METHODS: Using a randomised crossover study design 6 trained horses were studied during experimental showjumping sessions over 10 fences of different height: 1.00 m (Session 1), 1.10 m (Session 2), 1.20 m (Session 3). Hormone levels were recorded before, after warm-up, 5 and 30 min post exercise. T(3), T(4), fT(3), fT(4) concentrations were analysed by ELISA/competition using streptavidin technology. RM-ANOVA was applied to test for any differences in basal and warm-up values of different sessions. Two way RM-ANOVA was applied to test for any effects of interaction between fence height and time. The differences between individual means over time were assessed using a post hoc multiple comparison test (Bonferroni). RESULTS: Basal T(4) changes over the sessions (P < 0.05) were recorded. After warm-up, T(4) concentration results were lower than basal in Session 1 (P < 0.05). Higher than basal values were recorded 30 min post exercise for T(3) (P < 0.001), T(4) and fT(4) (P < 0.01) in Session 2 and for T(4) (P < 0.05) and fT(4) (P < 0.01) in Session 3. The interaction fence height/time results were significant on T(3) (P < 0.03) and fT(4) (P < 0.03); sampling time on T(3) (P < 0.0007), T(4) (P < 0.001) and fT(4) (P < 0.002) post exercise changes. CONCLUSION: Showjumping over the highest fences induced a release of T(3) from skeletal muscle, probably due to 5'-desiodase activity and increase of fT(4), due to thyroid stimulation and/or changes in capacity to bind iodothyronines.

Cortisol and haematochemical variables of horses during a two day trekking event: effects of preliminary transport.

REASONS FOR PERFORMING STUDY: Trekking is a noncompetitive sport, involving maximal skeletal muscle effort. Exercise and transport may involve significant energy expenditure and give rise to substantial stress. Few studies have examined the combined effect of exercise and additional preliminary transport on adrenocortical and haematochemical responses in horses during trekking. OBJECTIVES: To ascertain whether exercise and additional preliminary transport before trekking would affect the circulating cortisol levels and haematochemical variables of horses during a 2 day trekking event. MATERIALS AND METHODS: Twenty-nine healthy horses were used. Twenty-four horses were transported over distances of 70 km the day before trekking and 5 horses were stabled at the starting place. Blood samples were taken from horses at 16.00 h the day before trekking; and at 08.30 h and 17.30 h before and after the first day of trekking; at 08.30 h and at 13.30 h before and after the second day of trekking. Serum cortisol and haematochemical variables were determined in duplicate by using commercial test kits. One-way analysis of variance for repeated measures (RM-ANOVA) was applied to determine whether trekking and transport had any effects. RESULTS: Trekking significantly (P < 0.01) affected total protein, albumin, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), PCV and cortisol changes in transported horses and only urea and PCV (P < 0.01) changes in untransported horses. Untransported horses showed lower basal total protein (P < 0.05) and albumin (P < 0.01) concentrations, higher urea concentrations (P < 0.001) at the second day and lower cortisol levels after the first and the second (P < 0.05) day of trekking than transported horses. CONCLUSION: These data show that the preliminary transport stress induced additional significant changes of cortisol and haematochemical patterns in horses after trekking.

Effects of competitive and noncompetitive showjumping on total and free iodothyronines, ß-endorphin, ACTH and cortisol levels of horses.

REASONS FOR PERFORMING STUDY: Limited knowledge exists about the differentiated effects of competitive and noncompetitive showjumping on thyroid function and relationships with hypothalamic-hypophysis-corticoadrenal hormones. OBJECTIVES: To obtain preliminary data about differentiated effects of competitive and noncompetitive showjumping on total and free iodothyronines, ß-endorphin, ACTH and cortisol of horses. MATERIAL AND METHODS: Five trained healthy jumper horses were studied during competitive and noncompetitive showjumping, performed in the same circuit design over 10 fences of 1.10 m. Hormone levels before, 5 and 30 min post exercise were recorded. Serum iodothyronines and cortisol concentrations were measured in duplicate utilising EIA kits. Serum ACTH and plasma ß-endorphin concentrations were analysed in duplicate utilising RIA kits. Two-way RM ANOVA was applied to test for effects of interaction between different type of session and time. Significant differences between post exercise and basal values were established using Bonferroni's multiple comparison test. A linear correlation analysis (Pearson's method) was performed to analyse the relationships between total and free iodothyronines and between iodothyronines and ß-endorphin, ACTH and cortisol. RESULTS: In sampling times adopted no statistical different effects of type of session were recorded on hormone variables. Sampling time affected ACTH (F = 4.25; P < 0.02) and T(4) (F = 4.43; P < 0.02) post exercise changes. During the noncompetitive session, significant correlations existed between T(4) and ß-endorphin (r = -0.56), ACTH (r = -0.65), between ß-endorphin and ACTH (r = 0.52) and between T(3) and fT(3) (r = 0.72); during competition between ß-endorphin and T(3) (r = -0.67), fT(3) (r = -0.59). CONCLUSIONS: These preliminary results could demonstrate correlations between thyroid hormones and ß-endorphin response to showjumping, although no definitive conclusion can be produced concerning the relationships between HPA and thyroid function during exercise.

Physiological variables of horses after road transport.

In order to investigate the effects of short road transport stress on total and free iodothyronines, body weight (BW), rectal temperature and heart rate (HR) changes, 126 healthy stallions were studied in basal conditions, before and after transport. A total of 60 Thoroughbred and 66 crossbred stallions aged 4 to 15 years with previous travelling experience were transported by road in a commercial trailer for a period of about 3 to 4 h (distance under 300 km). Blood samples and functional variables were collected in each horse box, one week before loading and transport in basal conditions (control samples), one week later immediately before loading (pre-samples) and again after transport and unloading (about 3 to 4 h) in each new horse box, within 30 min of their arrival at the breeding stations (post-samples). Compared to the before-transport values, increases in circulating T3, T4 and fT4 levels (P < 0.01) were observed after transport, irrespective of breed, but not for fT3 levels. Lower T4 and fT4 levels were observed in basal II (at 1100 h) (P < 0.01) than in basal I (at 0800 h) conditions and before transport. Thoroughbreds showed higher fT3 (P < 0.05) and fT4 (P < 0.01) levels after transport than crossbred stallions. No significant differences were observed for T3 and T4. Compared to the before-transport values, significant increases in rectal temperature (P < 0.01) and HR (P < 0.05) were observed after transport. No differences were observed between basal I, II and before values for functional variables. Significant correlations between T3 and rectal temperature, BW and HR were found. The results indicate that short road transport induces a preferential release of T3, T4 and fT4 hormones from the thyroid gland in relation to different breed, and an increase in rectal temperature and HR. No significant changes in BW were observed. No differences were observed in relation to different ages. The data obtained suggest that the stallion's thyroid hormones and functional variables may play an important role in assessing the effects of transport stress and a horse's coping strategy.

Effects of competition experience and transportation on the adrenocortical and thyroid responses of horses.

To evaluate whether the amount of experience of sport horses and the stress of transport affected their adrenocortical and thyroid responses, the plasma concentrations of total cortisol and total and free iodothyronine of 63 horses were studied before and after show jumping competitions. There were 14 trained inexperienced jumpers (group 1), 20 trained experienced jumpers (group 2), 10 trained inexperienced jumpers that had been transported just before the competition (group 3) and 19 trained experienced jumpers that had been transported just before the competition (group 4). The concentrations were measured under basal conditions and five and 30 minutes after the competition. There were significant increases relative to the basal values in the total cortisol concentrations of all four groups of horses at five and 30 minutes (P<0.001), but there were no significant differences between the groups. In contrast, there were no significant changes in the concentrations of triiodothyronine, thyroxine and free thyroxine after the competition and there were no significant differences between the groups. However, the horses in group 2 had significantly lower basal concentrations of free triiodothyronine than the horses in groups 1, 3 and 4 and the difference was maintained at five and 30 minutes after the competition.

Effect of long-distance road transport on thyroid and adrenal function and haematocrit values in Limousin cattle: influence of body weight decrease.

The purpose of this study was to evaluate the effect of long-distance road transport as a relevant stressor on total and free iodothyronines, cortisol levels and haematocrit values in 10 male Limousin cattle. Serum T3,T4,fT3,fT4 and cortisol concentrations were analysed by immunoenzymatic assays. Serum cortisol levels and haematocrit modifications were also evaluated on the basis of percentage body weight decrease. The results showed a general increase of total and free iodothyronines and cortisol levels after short-and long-distance road transport and a decrease 15 days after transport, as compared to basal values. Significant positive correlations between T3 and T4, between T3 and fT3, and between T4 and fT4 were found. These results suggest that transport stress induces an increase in the activity of thyroid and adrenal function in Limousin cattle that is evident after even a short-distance road transport and continues to increase after long-distance transport.

Integration of genotoxicity and population genetic analyses in kangaroo rats (Dipodomys merriami) exposed to radionuclide contamination at the Nevada Test Site, USA.

We examined effects of radionuclide exposure at two atomic blast sites on kangaroo rats (Dipodomys merriami) at the Nevada Test Site, Nevada, USA, using genotoxicity and population genetic analyses. We assessed chromosome damage by micronucleus and flow cytometric assays and genetic variation by randomly amplified polymorphic DNA (RAPD) and mitochondrial DNA (mtDNA) analyses. The RAPD analysis showed no population structure, but mtDNA exhibited differentiation among and within populations. Genotoxicity effects were not observed when all individuals were analyzed. However, individuals with mtDNA haplotypes unique to the contaminated sites had greater chromosomal damage than contaminated-site individuals with haplotypes shared with reference sites. When interpopulation comparisons used individuals with unique haplotypes, one contaminated site had greater levels of chromosome damage than one or both of the reference sites. We hypothesize that shared-haplotype individuals are potential migrants and that unique-haplotye individuals are potential long-term residents. A parsimony approach was used to estimate the minimum number of migration events necessary to explain the haplotype distributions on a phylogenetic tree. The observed predominance of migration events into the contaminated sites supported our migration hypothesis. We conclude the atomic blast sites are ecological sinks and that immigration masks the genotoxic effects of radiation on the resident populations.

A prospective randomized trial of levothyroxine suppressive therapy for solitary thyroid nodules.

OBJECTIVE: We examined the effects of L-thyroxine therapy versus placebo over a 12-month period on volume of solitary thyroid nodules. DESIGN: Prospective randomized clinical trial; placebo and control groups followed for one year in three centres. PATIENTS: One hundred and one euthyroid patients with single palpable colloid thyroid nodules. MEASUREMENTS: Serum thyroid hormones, TSH, thyroglobulin, anti-thyroglobulin and anti-thyroid peroxidase antibodies measured at the first visit and after 2, 6 and 12 months; nodule volume and contralateral thyroid lobe thickness measured by ultrasound in double blind fashion; nodule diameter measured by palpation every 6 months. RESULTS: In the treatment group the nodule volume measured by ultrasound decreased progressively but not significantly; in the placebo group no changes were demonstrated. The number of nodules which decreased in size was however significantly larger in the treatment group. None of the initial parameters was predictive for the response. In the treatment group the nodule size assessed by palpation showed a significant decrease after 12 months when compared to baseline. CONCLUSIONS: In non-endemic areas TSH suppression induces nodule volume reduction measured by ultrasound which, although not significant, seems to be progressive and occurring only in a subgroup of patients. Significant palpatory nodule reduction is probably related to decreased thickness of the surrounding thyroid tissue still responsive to TSH.