Survival and the Development of Azotemia after Treatment of Hyperthyroid Cats

Background: Hyperthyroidism complicates the diagnosis of chronic kidney disease (CKD) as it increases glomerular filtration rate. No practical and reliable means for identifying those cats that will develop azotemia after treatment for hyperthyroidism has been identified. Hyperthyroidism is associated with proteinuria. Proteinuria has been correlated with decreased survival of cats with CKD and with progression of CKD. Hypothesis: Proteinuria and other clinical parameters measured at diagnosis of hyperthyroidism will be associated with the development of azotemia and survival time. Animals: Three hundred client owned hyperthyroid cats treated in first opinion practice. Methods: Retrospective, cohort study relating clinical parameters in hyperthyroid cats at diagnosis to the development of azotemia within 240 days of diagnosis and survival time (all cause mortality). Multivariable logistic regression analysis was used to identify factors that were predictive of the development of azotemia. Multivariable Cox regression analysis was used to identify factors associated with survival. Results: Three hundred cats were eligible for survival analysis and 216 cats for analysis of factors associated with the development of azotemia. The median survival time was 417 days, and 15.3% (41/268) cats developed azotemia within 240 days of diagnosis of hyperthyroidism. Plasma concentrations of urea and creatinine were positively correlated with the development of azotemia. Plasma globulin concentration was negatively correlated with the development of azotemia. Age, urine protein : creatinine ratio, and the presence of hypertension were significantly correlated with decreased survival time. Urine specific gravity and PCV were significantly correlated with increased survival time. Conclusions and Clinical Importance: The proteinuria associated with hyperthyroidism is not a mediator of progression of CKD; however, it does correlate with all cause mortality.     

Optimal Testing for Thyroid Hormone Concentration after Treatment with Methimazole in Healthy and Hyperthyroid Cats

Background: Methimazole suppresses thyroid hormone synthesis and is commonly used to treat feline hyperthyroidism. The degree of variation in thyroid hormone concentrations 24 hours after administration of methimazole and optimal time for blood sampling to monitor therapeutic efficacy have not been determined.
Objective: To assess thyroid hormone concentration variation in serum of normal and hyperthyroid cats after administration of methimazole.
Animals: Four healthy cats and 889 retrospectively acquired feline thyroid hormone profiles.
Methods: Crossover and retrospective studies . In the crossover study, healthy cats were treated with increasing doses of oral methimazole until steady state of thyroid suppression was achieved. Thyroid hormones and thyroid stimulating hormone (TSH) were serially and randomly monitored after methimazole. Paired t -tests and a 3-factor analysis of variance were used to determine differences between thyroid hormone concentrations in treated and untreated cats in the crossover study. Thyroid profiles from methimazole-treated hyperthyroid cats were retrieved from the Diagnostic Center for Population and Animal Health database and reviewed. Linear regression analysis evaluated relationships of dosage (mg/kg), dosing interval (q24h versus q12h), and time after methimazole to all thyroid hormone concentrations.
Results: All serum concentrations of thyroid hormones were significantly suppressed and TSH was significantly increased for 24 hours after administration of oral methimazole in healthy cats ( P < .005). In hyperthyroid cats, there were no significant relationships between thyroid hormone concentrations and time postpill or dosing interval.
Conclusions: Timing of blood sampling after oral methimazole administration does not appear to be a significant factor when assessing response to methimazole treatment.     

Correlation of Urine Protein/Creatinine Ratio and Twenty-Four-Hour Urinary Protein Excretion in Normal Cats and Cats with Surgically Induced Chronic Renal Failure

Urine protein/creatinine (UP/C) ratios and 24-hour urinary protein excretion were compared in clinically normal cats and cats with surgically induced chronic renal failure (CRF). Mean 24-hour urinary protein excretion in 30 clinically normal cats fed a 28% protein diet (dry weight basis) was 4.93 mg/kg/24-hour (SD = 1.34) with a range of 2.99 to 8.88. Mean UP/C ratio in these cats was 0.134 (SD = 0.037) with a range of 0.073 to 0.239. Mean 24-hour urinary protein excretion in CRF cats was 10.49 mg/kg/24-hour (SD = 11.28) with a range of 2.16 to 62.93. Mean UP/C ratio in the CRF cats was 0.359 (SD = 0.374) with a range of 0.061 to 1.916. Linear regression showed high correlation (R2 = 0.973, P less than 0.001) between 24-hour urinary protein excretion and UP/C ratio in clinically normal cats and cats with surgically induced chronic renal failure. The regression equation for 24-hour urinary protein excretion versus UP/C ratio was: 24-hour urinary protein excretion = 29.39 (UP/C) + 0.18. Results of this study indicate that UP/C ratios are a valid estimate of 24-hour urinary protein excretion in clinically normal and CRF cats. Dietary protein intake significantly affected UP/C ratios in clinically normal cats and cats with surgically induced CRF. Therefore, the influence of dietary protein should be considered when interpreting UP/C ratios.     

Short- and long-term follow-up of glomerular and tubular renal markers of kidney function in hyperthyroid cats after treatment with radioiodine

Hyperthyroidism can mask co-existing chronic kidney disease (CKD). Previous studies showed that post-treatment renal azotemia can be predicted by pre-treatment assessment of glomerular filtration rate (GFR). We hypothesized that treatment of hyperthyroidism may have different effects on glomerular and tubular function and these changes might be predicted by additional pre-treatment variables than GFR.     

Urinary Markers in Healthy Young and Aged Dogs and Dogs with Chronic Kidney Disease

Background: Blood urea nitrogen and serum creatinine concentrations only detect a decrease of >75% of renal functional mass. Therefore, there is a need for markers that allow early detection and localization of renal damage.
Hypothesis: Urinary albumin (uALB), C-reactive protein (uCRP), retinol binding protein (uRBP), and N -acetyl-β- d -glucosaminidase (uNAG) concentrations are increased in dogs with chronic kidney disease (CKD) compared with healthy controls and in healthy older dogs compared with young dogs.
Animals: Ten dogs with CKD, 10 healthy young dogs (age 1–3 years), and 10 healthy older dogs (age > 7 years) without clinically relevant abnormalities on physical examination, hematology, biochemistry, and urinalysis.
Methods: Urinary markers were determined using an ELISA (uALB, uCRP, and uRBP) or a colorimetric test (uNAG). Results were related to urinary creatinine (c). The fixed effects model or the Wilcoxon rank sum test were used to compare the different groups of dogs.
Results: uALB/c, uRBP/c, and uNAG/c were significantly higher in CKD dogs than in healthy dogs. No significant difference was found for uCRP, which was not detectable in the healthy dogs and only in 3 of the CKD dogs. Between the healthy young and older dogs, no significant difference was detected for any of the markers.
Conclusion: The urinary markers uALB/c, uRBP/c, and uNAG/c were significantly increased in dogs with CKD compared with healthy controls. Additional studies are needed to evaluate the ability of these markers to detect renal disease before the onset of azotemia.     

Cryptococcal Infection in Cats: Factors Influencing Treatment Outcome, and Results of Sequential Serum Antigen Titers in 35 Cats

The relationship between treatment outcome and location of cryptococcal infection, gender, magnitude of pretreatment cryptococcal antigen titers, results of feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) serology, and serial changes in antigen titers during and after treatment were evaluated in a prospective and nonrandomized study of 35 cats with cryptococcosis. A commercial cryptococcal latex agglutination kit (CALAS; Meridian Diagnostic Inc, Cincinnati, OH) was used to detect cryptococcal antigen in sera. All cats were treated with itraconazole (Sporanox; Janssen Pharmaceutica Inc, Titusville, NJ). Pre-treatment mean log titers for serum cryptococcal antigen were not influenced by location of the infection. Treatment outcome was not influenced by gender, location of the infection, or magnitude of pretreatment serum antigen titer. Treatment outcome was influenced by FeLV and FIV status; cats seropositive for FeLV or FIV had a higher likelihood of treatment failure ( P = .008). The cryptococcal antigen titers of cats successfully treated decreased with significant linearity over time during treatment (r = -.64, P < .000001), whereas the corresponding titers for cats not treated successfully did not decrease with significant linearity ( r = -.03, P > .9). For cats in which treatment was successful, antigen titers decreased significantly from pretreatment values by 1.3 orders of magnitude at 2 months after initiation of treatment. By 10 months after initiating treatment, log titers decreased by at least 2 orders of magnitude in all cats successfully treated, and 9 of 16 cats had undetectable titers. In contrast, in 5 of 6 cats in which treatment failed, antigen titers were unchanged or increased in magnitude even after at least 6 months of treatment.     

Exogenous Insulin Treatment after Hypofractionated Radiotherapy in Cats with Diabetes Mellitus and Acromegaly

Background: The optimal treatment for feline acromegaly has yet to be established. Surgical and medical therapies are minimally effective although radiotherapy might have greater efficacy. The purpose of this study was to review the response and outcome of cats with acromegaly and insulin-resistant diabetes mellitus (DM) to radiotherapy.
Hypotheses: That radiotherapy improves glycemic control in cats with acromegaly and that improved glycemic control is due to remission of clinical acromegaly; demonstrated by a fall in serum insulin-like growth factor-1 (IGF-1) concentrations.
Animals: Fourteen cats with naturally occurring acromegaly.
Methods: Retrospective case review; records of all cats treated for acromegaly with radiotherapy were reviewed from 1997 to 2008. Cats were selected on the basis of compatible clinical signs, laboratory features, and diagnostic imaging findings. Fourteen cats received radiotherapy, delivered in 10 fractions, 3 times a week to a total dose of 3,700 cGy.
Results: Thirteen of 14 cats had improved diabetic control after radiotherapy. These improvements were sustained for up to 60 months. DM progressed in 2 cats and 1 did not respond. Seven cats responded before the final treatment. Ten cats were euthanized, 1 as a consequence of radiotherapy. In 8 cats in which IGF-1 was measured after treatment, changes in its concentration did not reflect the clinical improvement in glycemic control.
Conclusions and Clinical Importance: Radiotherapy represents an effective treatment for cats with insulin-resistant DM resulting from acromegaly. IGF-1 concentration after treatment does not provide a suitable method by which remission from either acromegaly or insulin-resistant DM may be assessed.     

Serum troponin I levels in hyperthyroid cats before and after treatment with radioactive iodine

A raised concentration of serum cardiac troponin I (cTnI) is a sensitive marker of cardiac myocyte injury in the cat and assays developed for its measurement in human patients have been validated in the cat. Raised levels have been associated with a number of cardiac insults including hypertrophic cardiomyopathy and trauma. Hyperthyroidism is a common disease of older cats and excess thyroid hormone is known to produce significant cardiovascular effects in this species. This study evaluated the effect of treatment for hyperthyroidism with radioactive iodine on cTnI concentration, assessed the association between thyroxin levels and glomerular filtration rate (GFR) and cTnI concentration in cats treated for hyperthyroidism and described changes in echocardiographic parameters following treatment. Prior to the treatment serum cTnI was measured and echocardiography performed, thyroxin, cTnI, and echocardiography were then repeated at various time points following radioisotope therapy. The results show that higher thyroxin levels were significantly (P=0.002) associated with a higher likelihood of the cat presenting with detectable levels of cTnI. No significant association was found between GFR and presence of detectable levels of cTnI. Furthermore the results indicate that the effects of hyperthyroidism on echocardiographic parameters appear considerably less in this study than in previous studies and that the main outcome of treatment on these parameters is a significant reduction in fractional shortening (P=0.006). These results suggest that chronic exposure to excess thyroid hormone may induce myocyte damage of sufficient severity to raise serum cTnI concentration in a proportion of cats that resolves following establishment of a euthyroid state.     

Serum alpha 1-acid glycoprotein concentrations before and after relapse in dogs with lymphoma treated with doxorubicin

OBJECTIVE: To determine whether serum alpha 1-acid glycoprotein (AGP) concentration was a useful marker of relapse in dogs with lymphoma that were in clinical remission following treatment with doxorubicin. DESIGN: Cohort study. ANIMALS: 12 dogs with lymphoma and 10 healthy dogs. PROCEDURE: Serum AGP concentration was measured in the healthy dogs and in the dogs with lymphoma before treatment, 3 weeks after the first dose of doxorubicin was administered, and every 3 weeks thereafter until relapse (i.e., recurrence of clinically detectable disease such as palpable enlargement of peripheral lymph nodes). Serum AGP concentrations were determined by use of a radial immunodiffusion kit. RESULTS: Mean serum AGP concentration in healthy dogs was significantly less than concentration in dogs with lymphoma prior to treatment. Mean serum AGP concentrations after the first and each subsequent dose of doxorubicin were not significantly different from concentration in healthy dogs. However, mean serum AGP concentrations 3 weeks prior to and at the time of relapse were significantly higher than concentration measured after the first dose of doxorubicin, and were not significantly different from concentration measured before treatment. CLINICAL IMPLICATIONS: Results suggest that measuring serum AGP concentration may be a useful method of predicting relapse before recurrence of clinically detectable disease in dogs with lymphoma undergoing treatment with doxorubicin.     

The Treatment of Acute Glaucoma in Dogs and Cats

Objective: Glaucoma is an optic nerve disease that may result in rapid loss of vision. Early detection of acute glaucoma and aggressive treatment is important to preserve vision. Continued treatment is indicated in chronic glaucoma to alleviate discomfort associated with chronic elevated intraocular pressure.
Etiology: In primary glaucoma, an abnormal iridocorneal angle results in obstruction to outflow of aqueous humor. In secondary glaucoma, an otherwise normal iridocorneal angle is obstructed by abnormalities such as a luxated lens, neovascular membranes or inflammatory material.
Diagnosis: The diagnosis is made by a combination of clinical signs such as corneal edema, mydriasis, decreased vision, episcleral hyperemia, and confirmed by measuring an elevation in intraocular pressure. Complete ophthalmic examination, knowledge of breed predisposition to various ocular diseases and gonioscopy will aid in distinguishing between primary and secondary glaucoma
Therapy: Aggressive medical management is important in acute glaucoma. Surgical procedures are often indicated after initial emergency medical treatment of acute glaucoma. Chronic, painful blind eyes are best treated with one of various surgical procedures.
Prognosis: The prognosis for maintaining vision or regaining temporarily lost vision in acute glaucoma is related to numerous factors including time between onset of clinical signs and appropriate treatment, etiology of the glaucoma, initial response to therapy and client compliance.     

Serum Levels of Type III Procollagen Peptide in Equidae before and after Intestinal Ischemia

Serum levels of type III procollagen peptide (P-III-P) were measured by radioimmunoassay in clinically normal adult ponies (n = 15) and horses (n = 10). The mean serum levels of P-III-P from the ponies, 10.4 +/- 2.9 (SD) ng/mL, and the horses, 12.2 +/- 2.6 (SD) ng/mL, were not significantly different. Segments of jejunum were made ischemic to induce fibrous peritoneal adhesions in two ponies, and serum P-III-P levels were measured on days 4, 5, 7, 14, and 21. An exploratory celiotomy on day 21 revealed that the ischemic injury had induced fibrosis of the mesentery and bowel, but no adhesions had formed. The fibrotic mesentery contained type III collagen. The highest mean serum level of P-III-P, 23.0 +/- 3.5 (SD) ng/mL on day 7, was more than 4 SD above the mean from the normal ponies. There was a significant difference in the serum P-III-P levels in the ponies on days 0 (7.1 +/- 1.6 ng/mL) and 7 (23.0 +/- 3.5 ng/mL). Serum levels of P-III-P may be useful to study fibrosis associated with intestinal ischemia.     

Plasma clearance of exogenous creatinine, exo-iohexol, and endo-iohexol in hyperthyroid cats before and after treatment with radioiodine

BACKGROUND: Glomerular filtration rate (GFR) can be measured by clearance methods of different markers showing discrepancies and different reproducibility in healthy cats. Studies comparing different methods of GFR measurement in hyperthyroid cats have not yet been performed. HYPOTHESIS: Plasma clearance of exogenous creatinine (PECCT), exo-iohexol (PexICT), and endo-iohexol (PenICT) could lead to differences in GFR measurement and the need to use the same clearance method when comparing GFR before and after radioiodine treatment in hyperthyroid cats. ANIMALS: Fifteen client-owned hyperthyroid cats. METHODS: GFR was measured 1 day before and 1, 4, 12, and 24 weeks after treatment. Intravenous injection of iohexol was followed immediately by IV injection of creatinine. Plasma creatinine was measured by an enzymatic method. Plasma endo- and exo-iohexol were measured by high-performance liquid chromatography coupled to ultraviolet detection. RESULTS: Globally, the 3 GFR methods resulted in significantly different (P < .001) GFR results. GFR results among the different methods were the same (P= .999) at all time points. All 3 techniques indicated decreasing GFR after (131)I treatment. For each GFR technique, a significant decrease in GFR was observed between time point 0 and all other time points. This decrease stabilized 4 weeks after treatment, with very little decline afterward. CONCLUSION AND CLINICAL IMPORTANCE: It is mandatory to use the same GFR technique in follow-up studies. GFR testing at 4 weeks posttreatment could allow assessment of the final renal functional loss after treatment in hyperthyroid cats.     

雏鸡冷应激前后血清中差异蛋白质组学研究

本试验旨在比较分析雏鸡冷应激前后血清中蛋白质的表达差异,并对重点差异蛋白质进行鉴定。将30只雏鸡随机分为3组,分别为冷应激组、冷适应组和常温对照组,收集各组雏鸡的血液制备血清后进行双向凝胶电泳(2-DE),以获得血清蛋白质表达的2-DE图谱,对2-DE图谱进行差异分析(利用PDQuest 8.0软件),随后采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术对差异表达蛋白质进行鉴定,并利用蛋白质印迹(Western blot)方法进行验证。结果显示:通过2-DE对常温对照组、冷应激组和冷适应组雏鸡血清进行分析,得到了比较完整的差异蛋白质数据,共找到差异蛋白质点23个。采用MALDI-TOF-MS技术分析其中几个重复性好且较为明显的蛋白质点,成功鉴定出4个差异蛋白质,其中2个为果糖二磷酸醛缩酶C(ALDOC),是参与葡萄糖、能量代谢通路供能的相关蛋白;随后,对差异蛋白质ALDOC进行Western blot验证,所得结果与2-DE的结果相一致。结果表明,雏鸡冷应激前后血清中蛋白质的表达具有明显的差异,这些蛋白质的表达差异可能与冷应激有关。     

Biochemical and Antioxidant Changes in Plasma, Serum, and Erythrocytes of Horses before and after a Jumping Competition

We designed an experiment to determine the concentrations of a marker of lipid peroxidation in erythrocytes of horses submitted to jumping competitions. Erythrocytes of exercised horses showed a significant increase in the concentration of thiobarbituric acid-reactive species content immediately after exercise (P < .001), which returned to normal levels 24 hours after exercise. Nonprotein sulfhydryl groups and superoxide dismutase activity (EC 1.15.1.1) in erythrocytes were significantly higher 24 hours after exercise, as compared with the resting period and control group (P < .001). Immediately after exercise, horses had increased serum concentrations of uric acid (P < .002) and plasma lactate, as well as increased creatine kinase (EC 2.7.3.2) and lactate dehydrogenase (EC 1.1.1.28) activities (P < .001), as compared with resting period and control group. All parameters returned to normal values 24 hours after exercise, except for uric acid serum levels that remained increased (P < .001). We conclude that the oxidative stress in erythrocytes of exercised horses may contribute to tissue damage. In addition, our results showed that horses submitted to a jumping competition showed higher production of free radicals and as a consequence, lipid peroxidation.     

Magnetic stimulation of the radial nerve in dogs and cats with brachial plexus trauma: a report of 53 cases

Brachial plexus trauma is a common clinical entity in small animal practice and prognostic indicators are essential early in the course of the disease. Magnetic stimulation of the radial nerve and consequent recording of the magnetic motor evoked potential (MMEP) was examined in 36 dogs and 17 cats with unilateral brachial plexus trauma.Absence of deep pain perception (DPP), ipsilateral loss of panniculus reflex, partial Horner’s syndrome and a poor response to MMEP were related to the clinical outcome in 29 of the dogs and 13 of the cats. For all animals, a significant difference was found in MMEP between the normal and the affected limb. Absence of DPP and unilateral loss of the panniculus reflex were indicative of an unsuccessful outcome in dogs. Additionally, the inability to evoke a MMEP was associated with an unsuccessful outcome in all animals. It was concluded that magnetic stimulation of the radial nerve in dogs and cats with brachial plexus trauma may provide an additional diagnostic and prognostic tool.     

Serum concentrations of thyroxine and 3,5,3'-triiodothyronine in dogs before and after administration of freshly reconstituted or previously frozen thyrotropin-releasing hormone

Concentrations of serum thyroxine (T4) and 3,5,3'-triiodothyronine (T3) were determined after the administration of freshly reconstituted thyrotropin-releasing hormone (TRH), reconstituted TRH that had been previously frozen, or thyrotropin (TSH) to 10 mature dogs (6 Greyhounds and 4 mixed-breed dogs). Thyrotropin-releasing hormone (0.1 mg/kg) or TSH (5 U/dog) was administered IV; venous blood samples were collected before and 6 hours after administration of TRH or TSH. Concentrations of the T4 and T3 were similar (P greater than 0.05) in serum after administration of freshly reconstituted or previously frozen TRH, indicating that TRH can be frozen at -20 C for at least 1 week without a loss in potency. Concentrations of T4, but not T3, were higher after the administration of TSH than they were after the administration of TRH (P less than 0.01). Concentrations of T4 increased at least 3-fold in all 10 dogs given TSH, whereas a 3-fold increase occurred in 7 of 10 dogs given freshly reconstituted or previously frozen TRH. Concentrations of T4 did not double in 1 dog given freshly reconstituted TRH and in 1 dog given previously frozen TRH. Concentrations of T3 doubled in 5 of 10, 2 of 10, and 5 of 10 dogs given TSH, freshly reconstituted TRH, or previously frozen TRH, respectively. Results suggested that concentrations of serum T4 are higher 6 hours after the administration of TSH than after administration of TRH, using dosage regimens of 5 U of TSH/dog or 0.1 mg of TRH/kg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tolerability of Gemcitabine and Carboplatin Doublet Therapy in Cats with Carcinomas

Background: This study was performed to determine the toxicity of gemcitabine-carboplatin doublet therapy in cats with carcinomas.
Hypothesis: Gemcitabine and carboplatin are safe in tumor-bearing cats.
Animals: Twenty cats with spontaneously occurring carcinomas.
Methods: A cohort of 6 cats received gemcitabine (2 mg/kg IV) on days 1, 8, and 15 and carboplatin (10 mg/kg IV) immediately after gemcitabine on day 1 of a 21-day cycle. A 2nd cohort of 14 cats received carboplatin 4 hours after gemcitabine on day 1 and gemcitabine on day 8 but not day 15. The cycles were repeated every 21 days.
Results: Cats in the 1st cohort received a median of 3.75 cycles per animal (range, 1–6). Two cats (33.3%) developed grade 3 or 4 neutropenia, 1 (16.7%) grade 4 thrombocytopenia, and 1 (16.7%) grade 3 gastrointestinal toxicity. Gemcitabine dose reductions and treatment delays occurred in 1 and 4 cats, respectively. Cats in the 2nd cohort received a median of 2 cycles per animal (range, 0.5–10). Two cats (14.3%) had grade 3 or 4 neutropenia and 1 (7.1%) had grade 3 and 4 gastrointestinal toxicity. One cat required gemcitabine dose reduction and 6 had treatment delays. In the 2nd cohort, of 11 cats with measurable tumors, there was 1 complete response (pancreatic carcinoma) and 1 partial response (squamous cell carcinoma, receiving concurrent nonsteroidal anti-inflammatory drugs).
Conclusions and Clinical Importance: Gemcitabine-carboplatin combination appears moderately well tolerated in tumor-bearing cats. Minimal patient benefit suggests that alternative schedules or combinations of gemcitabine with other agents should be explored.     

Vitamin D status before and after hypophysectomy in dogs with pituitary-dependent hypercortisolism

Both spontaneous hypercortisolism and chronic glucocorticoid treatment are associated with osteoporosis and low circulating concentrations of 1,25-dihydroxy-vitamin D in humans. Pituitary-dependent hypercortisolism (PDH) is a common disorder in dogs, but little is known about the vitamin D status of affected dogs. Pituitary-dependent hypercortisolism in dogs can be treated effectively by hypophysectomy and subsequent hormone supplementation. Because hormone supplementation does not include GH, dogs that have undergone hypophysectomy have low circulating concentrations of GH and IGF-1, which may result in low plasma 1,25-dihydroxy-vitamin D concentrations and consequently increased parathyroid hormone secretion. The aim of this study was to determine whether dogs with PDH need vitamin D supplementation before and/or after hypophysectomy. To this end, we measured plasma concentrations of GH, IGF-1, parathyroid hormone, calcium, phosphate, and vitamin D metabolites in 12 dogs with PDH before and 8 wk after hypophysectomy and in 12 control dogs. Although plasma GH concentrations were lower in dogs with PDH than in control dogs both before and after hypophysectomy, the vitamin D status was similar. In conclusion, there is no need for vitamin D supplementation in dogs with PDH, either before or after hypophysectomy.     

Tissue Doppler Imaging and Two-dimensional Speckle Tracking of Left Ventricular Function in Horses Affected with Recurrent Airway Obstruction before and after Clenbuterol Treatment

Cardiac effects of the β₂-adrenergic agent clenbuterol have been the focus of many studies, but effects on myocardial velocities and myocardial deformation parameters have not yet been evaluated in horses affected with recurrent airway obstruction (RAO) using tissue Doppler imaging (TDI) and two-dimensional speckle tracking (2DST). In our study, 7 horses affected by RAO were treated over 14 days with clenbuterol, 0.8 μg/kg every 12 hours. Standard echocardiographic, TDI (pulsed wave and color TDI), and 2DST examinations were performed before and after the treatment period. Myocardial function was recorded in the right parasternal short-axis view. Percent of fractional shortening and two-dimensional echocardiography (2DE) measurements did not show any significant changes after 2 weeks of treatment. Early diastolic velocity, E, increased significantly after clenbuterol in the left ventricular free wall (LVFW; P = .001). The E/late diastolic velocity (A) quotient (P = .003) and the isovolumetric contractility (P = .035) also increased significantly after treatment. Time parameters, particularly the time interval between the Q-wave in the echocardiograph and atrial release, the time of diastole and Tei index (parameter of global ventricular function), decreased significantly after clenbuterol administration in the LVFW (P = .014/P = .028/P = .015, respectively). The 2DE speckle tracking revealed a significant increase of the early diastolic systolic strain rate (P = .01) in the LVFW after therapy. In conclusion, 2 weeks of treatment with clenbuterol at a dosage of 0.8 μg/kg every 12 hours led to improved cardiac function in severely RAO-affected horses. This could be a sign of myocardial restoration (re-remodeling) after therapy.