Suppression In Cats Research Articles

Identification and structural elucidation of an oxidation product generated during stability studies of Cabergoline drug product

Cabergoline is a dopamine agonist with applications as anti-Parkinson drug and prolactin inhibitor. The cabergoline drug product Laktostop® 50 µg/mL is used in veterinary medicine for lactation suppression in cats and dogs e.g. during false pregnancy. Recently, during ongoing HPLC stability testing of Laktostop® 50 µg/mL a new oxidation product of Cabergoline was identified. A synthesis starting from Cabergoline was developed, followed by full characterization of the unknown impurity. Preliminary HPLC and LC-MS analyses indicated the unknown impurity as mono-oxygenated product of Cabergoline (Cabergoline N-oxide) that is presumably formed with oxygen by a radical mechanism. Thus, Cabergoline was treated with oxidizing agents such as m-chloroperoxybenzoic acid to afford the desired Cabergoline-N-oxide as a byproduct. After isolation by column chromatography, NMR and LC-MS-MS studies provided evidence that oxidation occurred at the N-allyl nitrogen of Cabergoline to form Cabergoline-N-oxide. © 1905 Elsevier Science. All rights reserved

Behavioral correlates of urinary output in shelter cats

United States’ animal shelters take in 3.2 million cats per year. Caged cats likely experience stressful situations during their stay at an animal shelter. However, a feasible and efficient way to determine which cats will be at the highest risk for severe stress, and subsequent health and behavior deterioration, is needed. We aimed to determine whether urinary output was suppressed immediately following a presumably stressful move from one location to another in the shelter and whether this suppression correlated with behavior in cats admitted to an animal shelter. Prior to addressing this aim, we first evaluated the use of litter clump weight to determine urine output. Then we aimed to determine whether behavior, using an established in-cage assessment, predicted urinary suppression in cats. Litter clump weight was significantly predicted by quantities of water added to the litter (50 mL, 100 mL, and 150 mL), suggesting that litter clump weight can be used as a marker of crude urine output. Next, newly-admitted shelter cats (n = 29) were subjected to an in-cage behavioral assessment. For the following week, urine clumps were weighed daily. Clump weight increased significantly (F = 17.926, p < 0.0001) after Day 1, suggesting an initial suppression perhaps due to acute stress (i.e. moving to the adoption floor). A principle component analysis (PCA) of in-kennel behavior followed by linear regression was conducted to predict Day 1 urine suppression and found that the sixth and eighth components (PC 6 and PC 8) showed modest prediction of urine suppression. A support vector machine (SVM) was also used to classify cats as having “less” vs. “more” urine suppression at three different cutoffs (10 %, 25 %, 50 % suppression on Day 1). The SVM had an average training accuracy of 86.3 %, 81.8 %, 84.1 % at 10 %, 25 %, and 50 % suppression respectively. These data suggest that urinary suppression (measured through litter clump weights) may be a practical way to track wellbeing in shelter cats and that a SVM may have modest ability to classify cats at risk of suppressed urine output based on behavioral responses to a brief test.

TGR5/Cathepsin E signaling regulates macrophage innate immune activation in liver ischemia and reperfusion injury.

The role and underlying mechanism of plasma membrane-bound G protein-coupled bile acid receptor (TGR5) in regulating macrophage innate immune activation during liver ischemia and reperfusion (IR) injury remains largely unclear. Here, we demonstrated that TGR5 depletion in myeloid cells aggravated liver injury with increased macrophage infiltration and enhanced inflammation in livers post-IR. While TGR5 deficiency enhanced mobility and proinflammatory M1 polarization of macrophages, TGR5 agonist enhanced the anti-inflammatory effect of TGR5 both in vivo and in vitro. Microarray profiling revealed that TGR5-deficient macrophages exhibited enhanced proinflammatory characteristics and cathepsin E (Cat E) was the most upregulated gene. Knockdown of Cat E abolished the enhanced mobility and shift of macrophage phenotypes induced by TGR5 depletion. Moreover, Cat E knockdown attenuated liver IR injury and liver inflammation in myeloid TGR5-deficient mice. In patients undergoing partial hepatectomy, IR stress promoted TGR5 activation of CD11b+ cells in peripheral blood mononuclear cells, correlating with the shift in macrophage M2 polarization. Ursodeoxycholic acid administration enhanced TGR5 activation and the trend in macrophage M2 polarization. Our results suggest that TGR5 attenuates proinflammatory immune activation by restraining macrophage migration and facilitating macrophage M2 polarization via suppression of Cat E and thereby protects against liver IR injury.

Evaluation of Gastric pH and Serum Gastrin Concentrations in Cats with Chronic Kidney Disease.

BackgroundChronic kidney disease (CKD) is a highly prevalent condition in cats. Advanced CKD is associated with hyporexia and vomiting, which typically are attributed to uremic toxins and gastric hyperacidity. However, gastric pH studies have not been performed in cats with CKD.Hypothesis/ObjectivesTo determine if cats with CKD have decreased gastric pH compared to age‐matched, healthy cats. Based on previous work demonstrating an association of hypergastrinemia and CKD, we hypothesized that cats with CKD would have decreased gastric pH compared to healthy, age‐matched control cats.Animals10 CKD cats; 9 healthy control cats.MethodsAll cats with concurrent disease were excluded on the basis of history, physical examination, CBC, plasma biochemistry profile, urinalysis, urine culture, serum total thyroxine concentration, and serum symmetric dimethylarginine concentration (controls only) obtained within 24 hours of pH monitoring and assessment of serum gastrin concentrations. Serum for gastrin determination was collected, and 12‐hour continuous gastric pH monitoring was performed in all cats. Serum gastrin concentration, mean pH, and percentage time that gastric pH was strongly acidic (pH <1 and <2) were compared between groups.ResultsNo significant differences in serum gastrin concentrations were observed between groups (medians [range]: CKD, 18.7 ng/dL [<10–659.0]; healthy, 54.6 ng/dL [<10–98.0]; P‐value = 0.713) or of any pH parameters including mean ± SD gastric pH (CKD, 1.8 ± 0.5; healthy, 1.6 ± 0.3; P‐value = 0.23).Conclusions and Clinical ImportanceThese findings suggest that cats with CKD may not have gastric hyperacidity compared to healthy cats and, therefore, may not need acid suppression. Thus, further studies to determine if there is a benefit to acid suppression in cats with CKD are warranted.

Impact of olmesartan medoxomil on atherosclerosis lesions in apolipoprotein E knockout mice

To investigate the effect and possible mechanisms of olmesartan medoxomil on atherosclerosis of apolipoprotein E knockout (ApoE(-/-)) mice. Sixteen 6-week-old male ApoE(-/-) mice were randomly divided into atherosclerosis model group fed with high fat diet, and olmesartan medoxomil intervention group fed with high fat diet and olmesartan medoxomil (10 mg·kg(-1)·day(-1,) per gavage). Eight C57BL/6 mice were fed with normal diet, and treated for 12 weeks.The blood pressure and the serum level of lipid were detected; the aorta were removed, oil red staining for plaque area, Hematoxylin and eosin (HE) staining for plaque morphology, Elastica van Gieson (EVG) staining for elastin, and picrosirius red (PSR) for collagen respectively; and the expression of cathepsin S (Cat S), smooth action protein (ASMA) and macrophage surface molecule-3 (Mac-3) were detected by immunohistochemisty analysis. Serum cholesterol and low density lipoprotein levels were significantly higher in atherosclerosis model group than in control group[(15.08±1.64) vs (2.06±0.15) mmol/L, (15.60±1.05) vs (0.00±0.00) mmol/L] (all P<0.01), while triglyceride level was similar between the two group.In contrast to model group, the mice in intervention group showed no statistical difference in blood pressure and plasma lipid levels, while the plaque areas in the aorta were significantly decreased (P<0.05) as well as the expression of Cat S and Mac-3[(2.4±1.2) vs (8.8±3.2)%, (2.2±1.2) vs (7.2±2.8)%] (all P<0.01). In addition, the elastin levels, collagen contents, and the expression of ASMA remained significantly higher compared with model group (P<0.05). Olmesartan medoxomil could slow down the atherosclerosis process, the possible mechanism was implicated with the suppression of Cat S and decreased inflammatory responses alongside the increased elastin and collagen contents.

Evaluation of the effect of orally administered acid suppressants on intragastric pH in cats.

BackgroundAcid suppressant drugs are a mainstay of treatment for cats with gastrointestinal erosion and ulceration. However, clinical studies have not been performed to compare the efficacy of commonly PO administered acid suppressants in cats.Hypothesis/ObjectivesTo compare the effect of PO administered famotidine, fractionated omeprazole tablet (fOT), and omeprazole reformulated paste (ORP) on intragastric pH in cats. We hypothesized that both omeprazole formulations would be superior to famotidine and placebo.AnimalsSix healthy adult DSH colony cats.MethodsUtilizing a randomized, 4‐way crossover design, cats received 0.88–1.26 mg/kg PO q12h fOT, ORP, famotidine, and placebo (lactose capsules). Intragastric pH monitoring was used to continuously record intragastric pH for 96 hours beginning on day 4 of treatment. Plasma omeprazole concentrations at steady state (day 7) were determined by high performance liquid chromatography (HPLC) with ultraviolet detection. Mean percentage time that intragastric pH was ≥3 and ≥4 were compared among groups using ANOVA with a posthoc Tukey‐Kramer test (α = 0.05).ResultsThe mean percentage time ± SD that intragastric pH was ≥3 was 68.4 ± 35.0% for fOT, 73.9 ± 23.2% for ORP, 42.8 ± 18.6% for famotidine, and 16.0 ± 14.2% for placebo. Mean ± SD plasma omeprazole concentrations were similar in cats receiving fOT compared to those receiving ORP and in a range associated with acid suppression reported in other studies.Conclusions and Clinical ImportanceThese results suggest that both omeprazole formulations provide superior acid suppression in cats compared to famotidine or placebo. Fractionated enteric‐coated OT is an effective acid suppressant despite disruption of the enteric coating.

Global analysis of CpG methylation reveals epigenetic control of the radiosensitivity in lung cancer cell lines

Epigenetic regulation by CpG methylation has an important role in tumorigenesis as well as in the response to cancer therapy. To analyze the mechanism of epigenetic control of radiosensitivity, the CpG methylation profiles of radiosensitive H460 and radioresistant H1299 human non-small cell lung cancer (NSCLC) cell lines were analyzed using microarray profiling. These analyses revealed 1091 differentially methylated genes (DMG) (absolute difference of mean beta-values, |Deltabeta |>0.5), including genes involved in cell adhesion, cell communication, signal transduction and transcriptional regulation. Among the 747 genes hypermethylated in radioresistant H1299 cells, CpG methylation of SERPINB5 and S100A6 in radioresistant H1299 cells was confirmed by methylation-specific PCR. Reverse transcriptase-PCR showed higher expression of these two genes in radiosensitive H460 cells compared with radioresistant H1299 cells. Downregulation of SERPINB5 or S100A6 by small interfering RNA in H460 cells increased the resistance of these cells to ionizing radiation. In contrast, promoter CpG sites of 344 genes, including CAT and BNC1, were hypomethylated in radioresistant H1299 cells. Suppression of CAT or BNC1 mRNA expression in H1299 cells also reduced the resistance of these cells to ionizing radiation. Thus, we identified DMGs by genome-wide CpG methylation profiling in two NSCLC cell lines with different responses to ionizing radiation, and our data indicated that these differences may be critical for epigenetic regulation of radiosensitivity in lung cancer cells.

A common contrast pooling rule for suppression within and between the eyes

Recent work has revealed multiple pathways for cross-orientation suppression in cat and human vision. In particular, ipsiocular and interocular pathways appear to assert their influence before binocular summation in human but have different (1) spatial tuning, (2) temporal dependencies, and (3) adaptation after-effects. Here we use mask components that fall outside the excitatory passband of the detecting mechanism to investigate the rules for pooling multiple mask components within these pathways. We measured psychophysical contrast masking functions for vertical 1 cycle/deg sine-wave gratings in the presence of left or right oblique ( 16%. We tested contrast gain control models involving two types of contrast combination on the denominator: (1) spatial pooling of the mask after a local nonlinearity (to calculate either root mean square contrast or energy) and (2) (Holmes & Meese, 2004, Journal of Vision 4, 1080-1089), involving the linear sum of the mask component contrasts. Monoptic and dichoptic masking were typically better fit by the spatial pooling models, but binocular masking was not: it demanded strict linear summation of the Michelson contrast across mask orientation. Another scheme, in which suppressive pooling followed compressive contrast responses to the mask components (e.g., oriented cortical cells), was ruled out by all of our data. We conclude that the different processes that underlie monoptic and dichoptic masking use the same type of contrast pooling within their respective suppressive fields, but the effects do not sum to predict the binocular case.

Saccade-related activity in areas 18 and 21a of cats freely viewing complex scenes

Although saccadic eye movements can radically change the retinal image, perceptually their impact is surprisingly small. Here, we investigate possible neuronal correlates of saccadic suppression in cats freely viewing natural stimuli. By comparing changes attributable to saccadic events with passive stimulus changes, we find that during saccades: (i) evoked and induced activity is reduced in areas 18 and 21a by equal amounts, (ii) the variability of neuronal activity with stimulus category is abolished in both areas, and (iii) the high-power transient induced by stimulus change is not observed. These results present electrophysiological evidence for saccadic suppression at the level of primary and higher visual cortex under natural conditions.

Antisense inhibition of cathepsin B in a human osteosarcoma cell line.

Tumor invasion and metastasis are complex, multistep processes involving cellular detachment from primary sites, adhesion to extracellular/cellular matrices, local proteolytic degradation of matrix proteins and migration. Several proteases are involved in these complex processes. Besides matrix metalloproteases (MMP's) (Liotta and StetlerStevenson, 1990) and the urokinase-type plasminogen activator (u-PA) (Schmidt et al 1992), cathepsin B (cat B) (Sloane et al. 1990) is considered to play important roles in the different destructive occurrences. Besides direct proteolysis of components of the basement membrane and extracellular matrix, cat B participates in enzyme activation cascades, including other cathepsins and uPA (Kobayashi et al 1991). To block not only the catalytic activity of the cysteine protease cat B (e.g. by anticatalytical antibodies), the osteosarcoma cell line MNNG/HOS was stably transfected with antisense cat B constructs, resulting in direct suppression of cat B expression in the tumor cells. We selected cell clones with the lowest enzyme expression to functionally characterize them in invitro assays of invasion and motility, compared with the parental cell line MNNG/HOS.

Neuronal structures of the brainstem participating in postural suppression in cats

Two histochemical tracer techniques (a horseradish peroxidase and a Phaseolus vulgaris leucoagglutinin axonal flow technique) were employed to determine the cells of origin, axonal trajectories and terminals of fibers of passage through the dorsal tegmental field (DTF) in the pons along the midline (Horsley-Clarke coordinates, P 3 to P 7, LR 0, H - 4.5 to H - 6.0). Stimulation of the DTF area results in the postural suppression in both acute decerebrate, reflexively standing cats and freely moving awake cats. With these techniques, we have been able to demonstrate that in addition to pontine reticular cells, many cells in the dorsolateral pontine tegmentum, including the LC-complex, project their axons to the rostral part of the midline DTF area, and that descending axons from the nucleus reticularis pontis oralis pass through the DTF area and terminate on cells in the nucleus reticularis pontis caudalis and the nucleus reticularis gigantocellularis. Among those cells in the nucleus reticularis gigantocellularis, a great number of giant cells project to the lumbar spinal cord. The functional roles of these neuronal structures are discussed in relation to the results obtained by chemical stimulation of the pontine structures.

Responses of Raphe-Spinal Neurons to Stimulation of the Pontine Parabrachial Region Producing Behavioral Nociceptive Suppression in the Cat

Cholinergic stimulation of the pontine parabrachial region (PBR) produces behavioral nociceptive suppression in the awake cat. This report shows that electrical stimulation of both PBR sites (verified to be associated with behavioral nociceptive suppression on cholinergic stimulation) and the periaqueductal gray (PAG) excites raphe-spinal neurons which have been implicated in descending nociceptive suppression. Although several lines of evidence have strongly indicated that pathways from the PBR and PAG for nociceptive suppression are anatomically as well as neurochemically distinct, the results of the present study appear to suggest that certain components of the pathways from the PBR may be synergic in function with those from the PAG with regard to the activity of raphe-spinal neurons.

REM sleep suppression in cats by melatonin

The pineal indole melatonin, injected into the third ventricle of unanesthetized cats, induced NREM sleep within 11–15 min and suppressed REM sleep for about 3 hr. A dose-related effect could be established between 1, 10 and 100 ng melatonin. The reappearance of REM sleep at about 3 hr following melatonin administration occurred with a marked rebound. The present results further support the hypothesis that melatonin represents the releasing hormone for pineal arginine vasotocin.

Two-Tone Suppression in Cat Auditory-Nerve Fibers: Comparison of Frequencies above and below Fiber CF

Responses of cat auditory-nerve fibers to two-tone stimuli have been measured. One tone was always at the fiber's characteristic frequency (fc). The other tone (at frequency f2) was always such that it could produce two-tone suppression when presented at an appropriate sound level. We concentrate on cases where f2 does not produce a change in rate when presented alone. We define “fractional response” to be the average rate to the sum of the two tones divided by the rate to the CF tone presented alone. The dependence of fractional response on stimulus parameters for f2 &amp;gt;fc was different from its dependence for f2&amp;lt;fc. In one series of experiments the ratio of the sound levels of the two tones was held constant; i.e., sound pressure was given by p(t) = P0 (sin2πfct +D0 sin2πf2t), D0 = constant. Fractional response was measured as a function of P0. For f2&amp;gt;fc, fractional response was approximately constant (less than 1) for P0 between fiber “threshold” and saturation; for higher Po fractional response increased, in some cases to 1. However, for f2&amp;lt;fc, fractional response was a monotonically decreasing function of P0. [Supported by the National Institutes of Neurological Diseases and Stroke and General Medical Sciences and the U. S. Air Force Office of Scientific Research.]