Assessment of discomfort in rats with hepatomegaly

An attempt was made to assess discomfort in rats with hepatomegaly induced by feeding a high cholesterol, high cholate diet. After 8 weeks, the rats displayed a more than two-fold increase in liver weight when compared with controls fed a commercial diet. In a small open field test, behaviour of rats with hepatomegaly was similar to the controls. Of 9 parameters scored per rat, only the response to pressure on the right hypochondrium (tension of overlying muscles) scored higher than in control animals. There was considerable between-assessor variation in the assignment of scores. It is suggested, tentatively, that hepatomegaly in rats caused by cholesterol plus cholate feeding, may not cause extreme discomfort. Upon 'blind' palpation of control and test rats, an average of 60% of the rats with hepatomegaly were classified correctly.     

Hepatic cholesterol metabolism in cholesterol gallstone disease

Hepatic cholesterol metabolism was examined in 27 Swedish patients with cholesterol gallstone disease and in 13 patients free of gallstones operated for roentgenographically suspect polyps in the gallbladder. All 40 patients underwent cholecystectomy, and a liver biopsy and gallbladder bile were obtained at surgery. The cholesterol saturation of gallbladder bile was significantly higher in patients with gallstones compared to the gallstone-free controls (131 +/- 13 vs. 75 +/- 5%, P less than 0.001). Microsomal 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, governing cholesterol synthesis, did not differ between gallstone and gallstone-free patients (104 +/- 11 vs. and 109 +/- 22 pmol/min per mg protein, respectively). The activity of cholesterol 7 alpha-hydroxylase, catalyzing the catabolism of cholesterol to bile acids, was not significantly decreased in gallstone patients (6.2 +/- 1.1 vs. 8.0 +/- 2.0 pmol/min per mg protein). The capacity to esterify cholesterol, judged by the activity of acyl coenzyme A:cholesterol acyltransferase (ACAT), was similar in gallstone and gallstone-free patients (5.4 +/- 0.4 vs. 6.7 +/- 1.1 pmol/min per mg protein). In the presence of exogenous cholesterol, ACAT activity increased by more than fourfold in both groups. No correlation was found between the saturation of gallbladder bile and any of the mentioned enzyme activities in gallstone patients. It is concluded that distinct abnormalities in cholesterol metabolizing enzymes are not of major importance for development of gallstones in Swedish patients with cholesterol gallstone disease. The results support the contention that the etiology of cholesterol gallstones is multifactorial.     

Accelerated development of uroporphyria in mice heterozygous for a deletion at the uroporphyrinogen decarboxylase locus

Three weeks after a single dose of iron-dextran and Aroclor 1254, mice maintained continuously on delta-aminolevulinic acid supplemented drinking water showed significantly elevated levels of hepatic uroporphyrin and depressed (25% of normal) uroporphyrinogen decarboxylase (URO-D) activity. Depressed URO-D activity was paralleled by the ability of heat denatured cytosol to inhibit rhURO-D activity. Mice heterozygous for a targeted disruption at the URO-D locus (URO-D+/-) exhibited half the URO-D activity of homozygous controls prior to treatment. After treatment, these animals showed URO-D activity and rhURO-D inhibitory activity comparable to similarly treated wild type (URO-D +/+) mice but with significantly greater uroporphyrin accumulation. With only 10 days of treatment, URO-D +/- but not URO-D +/+ mice showed changes similar in magnitude to those seen after 21 days. Prior to treatment, URO-D genotype did not influence overall hepatic P450 concentration in either sex and there was no significant difference between sexes. The treatment regimen significantly elevated P450 in animals of either URO-D genotype and in both sexes, although the induction response at the 10-day point was attenuated in URO-D +/- mice. From differences in the CO absorbance maximum, and by P450 activity analysis, this attenuated induction response resulted from an attenuation of the CYP2B not the CYP1A induction.     

The strategy of submissive behavior in male mice: the effect of the genotype and the experience of preceding agonistic encounters]

The male mice of two strains with experience of 2 or 10 defeats in intermale agonistic confrontations significantly differ in pattern of submissive behavior (balance of upright and sideways defensive postures, withdrawal, freezing, "on the back" posture). In mice with experience of 20 defeats genetic differences have not been found. The acquisition of consequent experience of defeats does not change the pattern of CBA mice submissive behavior, but significantly increases the share of immobile submissive postures in behavior of C57BL mice. Among submissive males of C57BL strain animals with more active strategy of behavior keep capability for aggressive response to weaker partner. The influence of genotype and previous social contact experience on formation of adaptive in experimental situation strategy of submissive behavior is discussed.     

Circulating antibody response of mice exposed to 9-GHz pulsed microwave radiation

Female CD-1 mice immunized against the bacterium Streptococcus pneumoniae type III were exposed to 9-GHz pulsed microwaves (pulse repetition rate 970-1,000, pulse width 1.0 microseconds, peak power 1 W/cm2) at an average incident power density of 1 mW/cm2 (calculated SAR congruent to 0.47 W/kg) for 2 h per day for 5 days. Circulating antibody titers for the microwave-exposed animals were not significantly different from those of the sham-irradiated animals, and there were no differences in any of the hematological parameters analyzed, indicating that 9-GHz pulsed microwaves at 1 mW/cm2 do not alter the immune response of mice immunized against S pneumoniae.     

Effect of summer conditions and shade on behavioural indicators of thermal discomfort in Holstein dairy and Belgian Blue beef cattle on pasture

Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾30°C), >50% of the animals under shade retained normal PS and RR (PS<1 and RR<90 breaths per minute), whereas normal RR and PS were significantly less prevalent for animals outside shade. Our findings suggest that, even in temperate summers, heat can induce thermal discomfort in cattle, as evidenced by increases in shade use, RR and PS, and that shade increases thermal comfort.     

Effect of the activation and blockade of D2 dopamine receptors on the immune response in mice with different types of social behavior

Activation of D2 dopamine receptors with a selective agonist quinpirol in C57BL/6J mice was found to induce increase in the immune response regardless of the initial psychoemotional state of animals, e. g. in aggressive mice, submissive mice, and mice without victory or defeat experience (control). However, the immune response level in aggressive and submissive mice was significantly higher than that of control animals. At the same time, the blockade of D2 dopamine receptors with haloperidol suppressed immunogenesis in aggressive and control mice, whereas the immune reactions in submissive mice were unchanged. Thus, the effect of activation and blockade of D2 dopamine receptors on immune function is dependent on the initial psychoemotional status of animals which to a greater extent might be provided by the neuromediator pattern of the brain and activity of DA receptors.     

Phenotypic and genetic correlations for body structure scores (frame) with productive traits and index for CEIP classification in Nellore beef cattle

The present study was carried out to estimate both (co)variance components and genetic parameters for frame scores obtained using two methods (FRAME_GMA and FRAME_BIF) as well as phenotypic and genetic correlations with traits such as weaning weight, weight gain from weaning to yearling, scrotal circumference, muscle score, and an empiric index for animal classification for the Special Certificate of Identification and Production (CEIP). Data on 12,728 animals, raised in Southeastern Brazil, with ages from 490 to 610 days were analyzed. Estimates of heritability for FRAME_GMA and FRAME_BIF in multi-trait analysis were 0.28 and 0.24, respectively. Genetic correlation coefficients between frame scores and the growth trait were of medium magnitude, which indicates that genetic selection for weight resulted in undesirable responses, increasing the animals' frames. Small changes should be expected in the frame of animals that have been submitted to a genetic selection regarding muscle score and scrotal circumference. The low magnitude of phenotypic and genetic correlation between frame scores and the empirical selection index that classifies animals for CEIP, a Brazilian official certificate that recognizes the value of seedstock that is not registered at breeders associations, but is genetically evaluated, does not indicate important responses in giving a CEIP to animals that have been directly or indirectly selected for frame. Other studies must be performed to determine estimates of the genetic parameters for frame scores in other beef cattle populations.     

Functional hypersplenism in mice induced by adoptive transfer of syngeneic spleen cells

Investigation of peripheral blood cell count alterations in cases with hypersplenism, and an understanding of the relationship between splenic function and hematopoietic cell production require suitable experimental animal models. Previously described methods are either traumatic or require surgical intervention. We suggest a relatively simple method for achievement of a state mimicking hypersplenism in mice by intraperitoneal inoculation of syngeneic spleen cells. Mice were inoculated intraperitoneally with 3 x 10(7) splenocytes suspended in 0.3 ml phosphate buffered saline (PBS). After 2 months, the inoculated animals showed a progressive decrease in the peripheral white blood cell (WBC) counts and hyperplastic bone marrow that persisted until the experimental end point (7 months). Five days after inoculation of splenocytes stained with carboxy-fluorescein diacetate succinimidyl ester (CFSE), the majority of the stained cells was present in the peritoneal cavity (33%) and in the liver (13%), whereas the percentage of stained cells in the peripheral blood and the spleen cell suspension was negligible. The mitogen response of the peripheral blood mononuclear cells (PBMC) from treated mice to concanavalin A (Con A) remained unaltered. Splenocyte-inoculated mice that were further splenectomized did not show leukocytosis after splenectomy, as was observed in animals in which the spleen was removed without any pretreatment. The lack of any signs of discomfort in animals from the study group, in comparison with the visibly ill appearance and even death of mice in which hypersplenism was achieved by repeated injections of methylcellulose (MC), which served as controls, favors the convenience of the method.     

Response of adrenal 3beta-hydroxy-delta5-steroid dehydrogenase to adrenocorticotropin treatment in thiouracil-fed male mice

A number of parallels can be drawn between the reported endocrine status of thiouracil-fed young rodents and that of aged animals, particularly with regard to the hypothalamus-pituitary-adrenal axis. Since the activity of the adrenal steroidogenic enzyme 3beta-hydroxy-delta5-steroid dehydrogenase (3beta-HSD) has been shown to be depressed in aged rats and mice, the present study was done to determine whether exposure of young mice to thiouracil had a similar effect on adrenal 3beta-HSD activity. Feeding the goitrogen thiouracil at 0.25% (w/w) of the maternal diet from conception, and keeping it 0.25% of the offsprings' diet after weaning, significantly elevated activity of 3beta-HSD per gram of adrenal gland above control levels in 4-month-old mice, perhaps to compensate for depressed adrenal mass. Daily subcutaneous injections of physiological saline (0.9%) for 4 days was sufficient to increase 3beta-HSD activity per gram of adrenal tissue in euthyroid (P less than 0.05) but not in thiouracil-fed mice. Subcutaneous administration of ACTH (2 IU daily for 4 days) significantly increased adrenal 3beta-HSD activity to comparable levels in thiouracil-fed and euthyroid animals. Thus, thiouracil enhances the activity of 3beta-HSD per gram of adrenal tissue and does not prevent response of enzyme activity to exogenous ACTH.     

Interruption of the enterohepatic circulation of bile acids stimulates the esterification rate of cholesterol in human liver.

The activity of acyl CoA: cholesterol acyltransferase (ACAT), which catalyzes the esterification of cholesterol, was studied in liver microsomes obtained from cholestyramine-treated gallstone patients (n = 12) and patients with Crohn's disease who had undergone partial ileal resection (n = 11). Gallstone patients (n = 33) and gallstone-free subjects undergoing cholecystectomy because of polyps of the gallbladder (n = 8) served as controls. The mean levels of the ACAT activity were the same in the gallstone and the gallstone-free patient groups (6.0 +/- 0.4 and 6.1 +/- 1.1 pmol/min per mg protein, respectively). When exogenous cholesterol was added to the assay system the activities were increased four- to fivefold in both groups. The ACAT activity tended to be increased in the cholestyramine-treated patients (8.1 +/- 1.8 pmol/min per mg protein), and was significantly enhanced (P less than 0.005) in the ileal-resected patients (12.3 +/- 2.3 pmol/min per mg protein). When the enzyme activity was determined with added exogenous cholesterol, it was significantly higher compared to the controls in both the cholestyramine-treated patients and the patients with ileal resection (57.9 +/- 11.6 and 50.0 +/- 10.3 pmol/min per mg protein, respectively). The content of free and esterified cholesterol in liver homogenates and microsomes was not significantly different between the patient groups. We conclude that ACAT activity is increased in patients with interruption of the enterohepatic circulation of bile acids, and speculate that this reflects a stimulated uptake of lipoprotein cholesterol and may indicate that more cholesteryl esters are incorporated into very low density lipoproteins.     

Superoxide dismutase and pulmonary ozone toxicity

Rats and mice were pre-exposed to low concentrations of ozone and subsequently challenged with higher concentrations of this gas. When the mortalities of pre-exposed and control animals were compared after a lethal challenge, there was a significant difference in ozone toxicity. The levels of superoxide dismutase in lung tissue of control and ozone tolerant rats or mice were not significantly different whether the results were expressed as units of activity per mg protein of lung tissue or as total units of enzyme activity per lung. Mice which were tolerant to ozone were not tolerant to oxygen. The data suggest that ozone tolerance is unrelated to an induction of superoxide dismutase. It is suggested that the induction of tolerance to oxygen and ozone involve biochemically distinct mechanisms.     

Susceptibility to collagen-induced arthritis is modulated by TGFβ responsiveness of T cells

The objective of our study was to determine the regulatory effects that endogenous transforming growth factor β (TGFβ) exerts on T cells in the pathogenesis of collagen-induced arthritis (CIA). CIA was induced in transgenic mice expressing a dominant negative TGFβ type II receptor in T cells under the control of the human CD2 promoter. Clinical and histological arthritis scores were determined and experiments on disease induction and the healing phase of disease were performed. The proliferation and cytokine production of draining lymph node cells in vitro were analyzed. Transgenic mice were more susceptible to induction of CIA. The overall incidence was higher in transgenic mice than in wild-type mice (57% vs 35%, P < 0.05). Affected transgenic animals displayed a significantly higher clinical (4.5 ± 0.6 vs 1.67 ± 0.19, P = 0.001) and histological arthritis score (8.01 ± 0.9 vs 4.06 ± 1.1, P < 0.05). Draining lymph node cells of transgenic mice secreted more tumor necrosis factor α and IFNγ and proliferated more vigorously in response to collagen type II and upon CD3/CD28 costimulation in vitro. Therefore, the regulation of T cells by endogenous TGFβ is important for the maintenance of joint integrity after arthritis induction. Defects in TGFβ-signalling as a susceptibility factor for rheumatoid arthritis may warrant further investigation.     

Stress fever magnitude in laboratory-maintained California ground squirrels varies with season

A previous study demonstrated that California ground squirrels (Spermophilus beecheyi) living in the natural environment had, independent of season, a significantly higher mean diurnal body temperature (T(b)) (39.6 degrees C) than either summer (37.5 degrees C) or winter (36.5 degrees C) laboratory maintained animals. Based upon the previous study it has been suggested that California ground squirrels living in the natural environment may have an elevated set-point for body temperature in a manner analogous to a stress fever response. The present study was conducted to determine if season and/or duration of laboratory open-field exposure influenced the magnitude of laboratory open-field stress fever. If stress fever was involved to some extent in the higher body temperature observed in animals from the natural environment, laboratory maintained animals should exhibit a lower magnitude stress fever during the summer months and a higher magnitude stress fever during the winter months. It was hypothesized that laboratory maintained animals would exhibit the same set-point for stress fever T(b) independent of season, and that the duration of open-field exposure would not influence the magnitude of stress fever. Adult California ground squirrels were acclimated to an ambient temperature of 20+/-1.0 degrees C under either LD 14:10 (summer) or LD 10:14 (winter) photoperiod conditions and individuals from both photoperiod conditions were exposed for periods of 2, 4, and 6 h to an open-field arena. An analysis of the data with a two-factor ANOVA demonstrated that season (photoperiod) significantly influenced the magnitude of the stress fever response (1.1+/-0.1 degrees C for summer animals; 2.1+/-0.2 degrees C for winter animals) while there was no significant influence of open-field exposure duration on stress fever magnitude. These results demonstrate that although the set-point for body temperature in unstressed laboratory maintained California ground squirrels varies with season, the set-point for body temperature in open-field stressed animals does not vary with season. These data lend support to the hypothesis that something like stress fever may play some role in the higher body temperature observed in California ground squirrels living in the natural environment.     

Response related enzymatic changes in ovaries of superovulated mice

Adult female mice were superovulated with PMSG followed by HCG and 140 blastocysts and 69 morulae were recovered from 24 mice. On the basis of the response, mice were divided into six groups; non responders, 1-5, 6-10, 11-20, 21-30 and >30 embryos. The ovaries of the animals were pooled group wise, homogenized in PBS (pH 7.4) and after centrifugation for 10-15 minutes, the supernatant was analyzed for the enzymes, guanine oxaloacetate transaminase (GOT), guanine pymvate transaminase (GPT), acid phosphatases (ACP) and alkaline phosphatases (AKP). Acid and alkaline phosphatase activities did not show any variation in relation to response to superovulation but GOT and GPT showed significantly increased activity in response to induction of superovulation. A statistically significant positive correlation was found between GOT and GPT activities and the superovulatory response in mice.     

Improved immune functions with administration of a low-fat diet in a burn animal model

The purpose of this study was to characterize the impact of a low-fat (LF; 1% fat) diet, a high-fat (HF; 25% fat) diet, and a standard (SD; 5% fat) diet on immune and oxidative parameters in a 20% body surface area burn animal model fed ad libitum for 10 days postinjury. Although the mechanisms are poorly understood, the amount of dietary lipid in nutritional support has been shown to have immunomodulatory effects after burn injury. Burned mice fed the LF diet showed a normal response in activated splenocyte proliferation compared to burned animals that received the SD or HF diet. Animals fed the SD and HF diets presented increased production of nitric oxide and prostaglandin E2 response after burn injury, which is associated with inhibited splenocyte proliferation. The total thiol concentration in spleen cells from burned animals kept on the HF diet was significantly higher than that in unburned animals, while no increase in these oxidative parameters was observed in LF-fed burned animals. Moreover, the LF diet significantly reduced hepatic lipid peroxidation, as measured by malonaldehyde concentration, compared to the other two diets. These results suggest that the administration of a LF diet in mice after a burn injury prevents inhibition of in vitro splenocyte proliferation and reduces the intensity of oxidative stress.     

Plasmodium yoelii: antibody response in resistant and susceptible mouse strains

The numbers of antigen-reactive antibody-secreting cells, levels of parasite antigen-specific serum antibodies and numbers of red blood cells staining positive for surface immunoglobulin were determined for susceptible and resistant mouse strains following infection with Plasmodium yoelii 17x. As a control, these parameters also were measured using antigen prepared from normal red blood cells. The relatively susceptible C57BL/6 mice produced more antigen-specific antibody-secreting cells and had higher levels of immunoglobulin positive red blood cells than did DBA/2 mice, but the DBA/2 mice had more antigen-specific IgG in their sera. Both mouse strains possessed cells secreting antibody reactive with soluble normal red blood cell antigen; however, C57BL/6 mice had more IgG positive unparasitized RBC than did DBA/2 mice. Despite possessing fewer antibody positive normal RBC, DBA/2 mice had significantly higher levels of serum antibodies that reacted with soluble red blood cell antigen. These data indicate that levels of serum antibody may not reflect the amounts of antibody produced and that use of any single assay to assess the magnitude of the antibody response may give rise to misleading results.     

An impaired response of adenylate cyclase to stimulation by epinephrine in adipocyte plasma membranes from genetically obese mice (ob/ob).

The present studies have established that there is an impaired response to epinephrine of the adenylate system in adipocyte preparations from obese hyperglycemic mice as compared to their thin littermates. In contrast, membrane preparations from both groups of animals were found to exhibit a similar response to fluoride ion. The response of adenylate cyclase to epinephrine was enhanced to a similar extent by increasing the ATP concentration in adipocyte plasma membranes from the two groups of animals. While GTP (0.1 muM) elicited an ATP-like response of similar magnitude in adenylate cyclase activity in both membrane preparations, it did not therefore abolish the impaired response to epinephrine of adenylate cyclase activity in membranes of obese mice. The response of adenylate cyclase activity to (--)-epinephrine in membrane preparations from obese mice progressively diminished with the age of these animals. In contrast, the concentration of (--)-epinephrine required for half-maximal stimulation of adenylate cyclase was similar and remained unchanged with the age for both membrane preparations. These data suggest that a perturbation may occur in the coupling step between the hormone receptor and the catalytic site of the adenylate cyclase system in obese mice. While a 15-day restrictive diet or a 72-h period of fasting was found to normalize the hyperinsulinemia of obese animals, neither affected the response of adenylate cyclase to epinephrine in preparations of adipocyte membranes from these mice. These results suggest that the observed defect in the response of plasma membrane adenylate cyclase activity to epinephrine in obese mice does not result from their hyperinsulinism.     

Participation of tissue basophils of the parathyroid glands in the regulation of the morphofunctional state of the organ

By means of cytometry estimation of mitotic index and nucleo-cytoplasmic relation of parathyrocytes, parathyroid glands have been studied in 52 white rats and 28 white mice under conditions of intal inhibition (30 mg/kg of body mass twice a day intraperitoneally) of tissue basophils (TB) secretory activity. For stimulation of the glands, repeated injections of trilon B and hemiparathyroidectomy are used. The experiment lasts for 3.5 days. In the rat parathyroid glands, containing a considerable amount of TB, intal does not produce any important effect of quantitative parameters of the organ's structure in intact animals, nevertheless it prevents development of hypertrophy of the parathyrocytes in the stimulated glands, as well as makes weaker the proliferative response of the cells to hemiparathyroidectomy. In mice, their parathyroid glands containing single TB, under conditions of stimulation of the parathyroid function, intal does not produce any inhibitory effect to growth of middle size parathyrocytes. The results obtained demonstrate that the parathyroid TB actively participate in regulation of the organ's morphofunctional state, intensifying the stimulating effect of hypocalcaemia to the parathyroid parenchyma.