Fetal and placental traits at day 35 of pregnancy in relation to the estrogen receptor genotype in pigs

Fetuses from gilts with estrogen receptor (ESR) genotype AA (AA-AA and AA-AB) and BB (BB-AB and BB-BB) were compared at Day 35/36 of pregnancy, to examine whether fetal ESR genotype nested within maternal ESR genotype would affect fetal traits. Furthermore the relation of fetal body weight and fetal heart weight to various placental traits were evaluated relative to ESR genotype. Fetal and placental weight and length, and implantation surface area were not affected by fetal ESR genotype nested within maternal ESR genotype. Fetal weight was related similarly to placental length, placental weight, and implantation surface area: up to a certain threshold value (40 cm, 40 g and 250 cm2, respectively), an increase in the trait was associated with an increase of fetal weight. Thereafter, fetal weight did not change anymore. Thus, at Day 35/36 of pregnancy porcine fetuses seem to have a maximum growth potential. The percentage of AA-AA fetuses that had not reached this maximum growth potential was larger than of the other three genotype combinations studied, and therefore a higher subsequent fetal mortality may be expected in this group. Hearts of AA-AB fetuses were significantly heavier than those of BB-AB and BB-BB fetuses and tended to be heavier than those of AA-AA fetuses. The reason for this hypertrophy is unclear, but might be related to a difference in placental vascularity. Heart weight of fetuses from BB gilts increased with fetal weight, while heart weights of fetuses from AA gilts did not. Heart weight increased with an increase of placental length and implantation surface area up to 51 cm and 437 cm2, respectively, and thereafter decreased again. For BB-AB fetuses a similar relation was found between heart weight and placental weight, while heart weight of the other three genotype combinations remained unaffected as placental weight increased. The fetus and placenta are continuously changing during early pregnancy, therefore different mechanisms may change the demands for cardiac output. However, keeping in mind that placental size and blood volume are relatively large, placental vascularity and vascular development may play a major role. Therefore, further research on heart size, placental size and vascularity, relative to ESR genotype, is recommended.     

SPF级与普通级小型猪主要脏器形态与脏器系数比较

目的比较两种不同微生物学控制等级的五指山小型猪主要脏器重量和相对重量差异。方法选取4月龄近交培育的五指山猪20头,其中普通级和SPF级各10头,雌雄各半,分别测定体重和7种主要脏器重量,分析两种不同微生物控制程度的小型猪主要脏器形态及脏器相对重量。结果SPF级小型猪体重显著低于普通级对照（P〈0.01）,前者肺和脾的形态发生改变,肝、心、脑和肾上腺的相对重量显著高于普通级对照（P〈0.01）,而SPF级的脾和肺的相对重量显著低于普通级对照（P〈0.01）。结论小型猪在不同微生物控制程度下体重和脏器系数存在显著差异,主要脏器形态与脏器系数差异可作为实验动物质量鉴定的参考依据。     

Restriction of placental function alters heart development in the sheep fetus

Placental insufficiency, resulting in restriction of fetal substrate supply, is a major cause of intrauterine growth restriction (IUGR) and increased neonatal morbidity. Fetal adaptations to placental restriction maintain the growth of key organs, including the heart, but the impact of these adaptations on individual cardiomyocytes is unknown. Placental and hence fetal growth restriction was induced in fetal sheep by removing the majority of caruncles in the ewe before mating (placental restriction, PR). Vascular surgery was performed on 13 control and 11 PR fetuses at 110-125 days of gestation (term: 150 +/- 3 days). PR fetuses with a mean gestational Po(2) < 17 mmHg were defined as hypoxic. At postmortem (<135 or >135 days), fetal hearts were collected, and cardiomyocytes were isolated and fixed. Proliferating cardiomyocytes were counted by immunohistochemistry of Ki67 protein. Cardiomyocytes were stained with methylene blue to visualize the nuclei, and the proportion of mononucleated cells and length and width of cardiomyocytes were measured. PR resulted in chronic fetal hypoxia, IUGR, and elevated plasma cortisol concentrations. Although there was no difference in relative heart weights between control and PR fetuses, there was an increase in the proportion of mononucleated cardiomyocytes in PR fetuses. Whereas mononucleated and binucleated cardiomyocytes were smaller, the relative size of cardiomyocytes when expressed relative to heart weight was larger in PR compared with control fetuses. The increase in the relative proportion of mononucleated cardiomyocytes and the relative sparing of the growth of individual cardiomyocytes in the growth-restricted fetus are adaptations that may have long-term consequences for heart development in postnatal life.     

Towards a molecular explanation of the high performance of the tuna heart

The tuna heart is capable of sustaining cardiac outputs that are high relative to other active teleost species. The question as to whether there are known molecular mechanisms to explain this phenomenon is examined. Unfortunately, the evidence at present is scant but the paper attempts to put existing knowledge into a contextual framework. It is known that the high cardiac outputs in tuna are due to the maximum heart rates that are high relative to other active teleost species. While the normalized stroke volume (ml/kg body weight) in tuna is in the same range as that of trout several important points are worth noting. The stroke volume in the tuna heart is generated in the face of an afterload that is two-fold higher (due to high ventral aortic pressure) than that observed in the trout or other teleosts. Since the stroke volume is predicated on the strength of ventricular contraction, the question then arises as to whether this is a consequence of factors intrinsic or extrinsic to the design of the cardiomyocytes that make up the myocardium. Two important extrinsic factors must be noted: the substantially higher normal operating temperatures and the apparent cardiac hyperplasia in the tuna. While the merit of these factors is discussed, the paper focuses on intrinsic factors. There is very little that has been determined to date that would indicate substantive changes in the design of the myocyte in the tuna heart compared to that of trout. Are these extrinsic factors alone then sufficient to account for the impressive cardiac output capabilities in the tuna?     

Effects of Brugia pahangi infection on the cardiovascular system of stroke-prone spontaneously hypertensive rats

To determine if filarial infection causes any effect on the cardiovascular system of the host animal, stroke-prone spontaneously hypertensive rats were infected with Brugia pahangi under the assumption that these rats would reveal pathological changes more clearly and in a shorter period than would ordinary rats. The infection resulted in loss of body weight, increase in heart weight, enlargement of left ventricle, and higher mortality rate.     

Genetic, environmental and maternal influences on embryonic cardiac rhythms

The relative roles of an animal's genetic constituents and environmental factors in influencing physiological variables such has heart rate have not been extensively investigated. This paper considers how heart rate patterns in the developing animal can be regulated, and how a combination of 'nature' and 'nurture' may interact to produce discrete patterns of heart rate change during development. The concept of the 'developmental trajectory' is evoked to generate a conceptual framework for how physiological development can be perturbed by environmental factors. Data are provided from three species showing how 'clutch-effects' (the fact that siblings perform physiologically much more similarly than non-siblings) can greatly influence the variance observed when collecting data on heart rate during development. Finally, so-called 'maternal effects', which are the influences on embryos of environmental experiences of the parents, are discussed as potentially confounding effects in the study of the genetic basis for physiological patterns of change during development.     

Meta-analytical study of productive and nutritional interactions of mycotoxins in growing pigs

A meta-analysis was carried out in order to study the association of mycotoxins with performance and organ weights in growing pigs. A total of 85 articles published between 1968 and 2010 were used, totaling 1012 treatments and 13 196 animals. The meta-analysis followed three sequential analyses: graphical, correlation and variance–covariance. The presence of mycotoxins in diets was seen to reduce the feed intake by 18% and the weight gain in 21% compared with the control group. Deoxynivalenol and aflatoxins were the mycotoxins with the greatest impact on the feed intake and growth of pigs, reducing by 26% and 16% in the feed intake and by 26% and 22% in the weight gain. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination in equations for estimating the effect of mycotoxins on weight gain. The mycotoxin effect on growth proved to be greater in younger animals. In addition, the residual analysis showed that the greater part of the variation in weight gain was explained by the variation in feed intake (87%). The protein and methionine levels in diets could influence the feed intake and the weight gain in challenged animals. The weight gain in challenged pigs showed a positive correlation with the methionine level in diets (0.68). The mycotoxin effect on growth was greater in males compared with the effect on females. The reduction in weight gain was of 15% in the female group and 19% in the male group. Mycotoxin presence in pig diets has interfered in the relative weight of the liver, the kidneys and the heart. Mycotoxins have an influence on performance and organ weight in pigs. However, the magnitude of the effects varies with the type and concentration of mycotoxin, sex and the animal age, as well as nutritional factors.     

Tameness correlates with domestication related traits in a Red Junglefowl intercross

Early animal domestication may have been driven by selection on tameness. Selection on only tameness can bring about correlated selection responses in other traits, not intentionally selected upon, which may be one cause of the domesticated phenotype. We predicted that genetically reduced fear towards humans in Red Junglefowl, ancestors of domesticated chickens, would be correlated to other traits included in the domesticated phenotype. Fear level was determined by a standardised behaviour test, where the reaction towards an approaching human was recorded. We first selected birds for eight generations for either high or low fear levels in this test, to create two divergent selection lines. An F3 intercross, with birds from the eighth generation as parentals, was generated to study correlations between fear-of-human scores and other unselected phenotypes, possibly caused by pleiotropy or linkage. Low fear-of-human scores were associated with higher body weight and growth rates, and with increased activity in an open field test, indicating less general fearfulness. In females, low fear-of-human scores were also associated with more efficient fear habituation and in males with an increased tendency to emit food calls in a mirror test, indicating increased social dominance. Low fear-of-human scores were also associated with smaller brain relative to body weight, and with larger cerebrum relative to total brain weight in females. All these effects are in line with the changes observed in domesticated chickens compared to their ancestors, and we conclude that tameness may have been a driving factor underlying some aspects of the domesticated phenotype.     

Relative hypertrophy of the right ventricle in silver foxes selected for domestication behavior

Silver foxes selected for domestication behavior were found to have relative hypertrophy of the right heart ventricle, which was 21% as enlarged in males and 18% as enlarged in females as compared with non-domesticated animals. It was established by stereological methods that hypertrophy occurs mainly at the expense of an increase in the absolute and relative content of myofibrils in cardiomyocytes, with the absolute total volume of the mitochondria being equal both in domesticated and non-domesticated animals. It was shown by means of dissociated cell counts that in both animal groups, the absolute number of cardiomyocytes and their nuclei in the right ventricles is approximately similar. It is suggested that there is a relationship between right heart ventricle hypertrophy in domesticated foxes and variation in the balance of sympathetic and parasympathetic effects.     

Genetic trends of absolute and relative heart weight in a male broiler line

Data of chickens from a broiler-breeding program have been collected and used for determination of genetic trends of absolute and relative heart weight. The genetic trends have been estimated by regression of the genetic values of the traits over hatch-year. Genetic values of 42,912 individuals, obtained by restricted maximum likelihood, were used for regression analysis. The estimates of the genetic trends for absolute and relative heart weight were found to be -0.08 g and -0.004% per hatch-year, respectively. These trends show that heart weight in the line analyzed, in absolute and relative terms, has tended to decrease, which can make the metabolic disorders due to the reduction in heart weight in broilers even worse.     

Body, heart, thyroid gland and skeletal muscle weight changes in rats with altered thyroid status

In the present paper we describe changes of anatomical parameters in inbred Lewis strain rats, namely their body weight, body weight gain per week, absolute and relative heart, thyroid gland and skeletal muscle weights, that are assumed to reflect experimentally altered thyroid status. The hyperthyroid state was induced by DL-thyroxine or Na 3,3',5-triiodo-L-thyronine, while methimazole was employed for inducing hypothyroidism. We have found that when compared to euthyroid rats, hypothyroidism resulted in a significantly lower body weight gain, absolute and relative heart weight and, in contrast, in a significant increase of absolute and relative thyroid gland weight. On the other hand, hyperthyroidism led to a significant increase of absolute and relative heart weight and to a significant reduction of absolute and relative thyroid gland weight. However, the body mass was not significantly altered in hyperthyroidism as compared with euthyroid rats. We conclude that our protocol leads to chronic hyper- or hypothyroidism as demonstrated by body, heart and thyroid gland weight changes. These anatomical data can thus be utilized as supplemental criteria for the assessment of the thyroid state of experimental rats.     

Further evidence validating adjuvant arthritis as an experimental model of chronic pain in the rat

The experiments described here were aimed at further validating adjuvant arthritis as an animal model of chronic pain. It was found that the relative oral intake of a 0.008 mg/ml solution of fentanyl was higher in arthritic than in normal control rats; this difference was predicted by the notion that the analgesic effect of a substance may reinforce its intake in animals exposed to pain, more so than in normal pain-free animals. It was also found that body weight decreases and that vocalizations of aggregated rats increase as a result of the challenge; these effects suggest that the vegetative signs and the behavioral irritability which are characteristic of chronic pain in humans, also occur in arthritic animals. The pain which thus seems to be associated with adjuvant arthritis was estimated to have its onset on days 10–11, to peak on days 18–21, and to terminate on days 35–40 after inoculation with $\text{Mycobacterium butyricum}$.     

Sex Differences in the Biomechanics and Contractility of Intramural Coronary Arteries in Angiotensin II–Induced Hypertension

BackgroundIt is well known that sex differences occur in both the pathogenesis and therapy of hypertension. A deeper understanding of the underlying processes may be helpful when planning a personalized therapeutic strategy.ObjectiveIn laboratory animal experiments, we studied the early mechanisms of vascular adaptation of the intramural small coronary arteries that play a fundamental role in the blood supply of the heart.MethodsIn our study, an osmotic minipump was implanted into 10 male and 10 female Sprague-Dawley rats. The pump remained in situ for 4 weeks, infusing a dose of 100 ng/kg/min angiotensin II acetate. Four weeks later, the animals were killed, and the intramural coronary arteries from the left coronary branch, which are fundamentally responsible for the blood supply of the heart, were prepared. The pharmacologic reactivity and biomechanical properties of the prepared segments were studied in a tissue bath.ResultsThe relative heart mass and vessel wall thickness were greater in females than males (0.387 [0.009] g/100 g vs 0.306 [0.006] g/100 g body weight; 41.9 [4.09] μm vs 33.45 [3.37] μm on 50 mm Hg). The vessel tone and vasoconstriction in response to thromboxane agonists were, however, significantly more pronounced in males. The extent of relaxation in response to bradykinin was also greater in females. Although we observed inward eutrophic remodeling in females, an increase in wall stress and elastic modulus dominated in males.ConclusionThe early steps of angiotensin II–dependent hypertension evoked very different adaptation mechanisms in males and females.     

The effect of sulfonylurea therapy on defective calcium movement associated with diabetic cardiomyopathy

Adult rats exposed to 70 mg/kg streptozocin developed characteristic symptoms of overt diabetes, such as muscle wasting and severely elevated blood glucose levels. Chronic treatment of these rats with the sulfonylurea glyburide for a period of 5 weeks did not affect either the weight of the animal or the degree of hyperglycemia. The drug also failed to influence myocardial glucose metabolism. Nevertheless, the decline in myocardial function associated with the diabetic cardiomyopathy was less in the glyburide-treated rats. At higher preload, myocardial work was significantly reduced in the untreated diabetic but was only moderately depressed in the glyburide-treated heart relative to the nondiabetic heart. The improvement in mechanical function was associated with partial recovery of sarcolemmal calcium pump activity. The drug did not alter the initial rate of Na+-Ca2+ exchange, but decreased the capacity of the transport system. The results indicate that glyburide benefits the diabetic heart by a mechanism independent of carbohydrate metabolism.     

Studies on the involvement of lipolytic enzymes in endogenous lipolysis of the isolated rat heart

Rat hearts were depleted in vivo from both the heparin-releasable lipoprotein lipase and heparin-resistant tissue neutral triacylglycerol lipase activity by treatment of the animals with cycloheximide (2 mg/kg body weight), intraperitoneally injected 2.5 and 5 h prior to perfusion. The tissue acid lipase, mono- and diacylglycerol lipase activities were not affected by cycloheximide-induced inhibition of protein synthesis. Myocardial basal and glucagon-stimulated lipolysis, determined by the rate of glycerol production and release from the isolated hearts, was not significantly different in control and cycloheximide-treated rats. Tissue triacylglycerols were recovered with the highest relative specific distribution in the lysosomal fraction isolated from heart homogenates. Upon prolongation of the perfusion-duration the relative specific distribution of triacylglycerols in the lysosomal fraction decreased. In addition, the specific lysosomal triacylglycerol content (micrograms/mg protein) dropped significantly, indicating an important role of lysosomes in myocardial triacylglycerol turnover. Our data strongly suggest that the heparin-resistant neutral triacylglycerol lipase activity may not be the only determinant of endogenous lipolysis in the isolated rat heart and indicate that lipolysis may additionally be mediated by the lysosomal, acid lipase in concert with the microsomal mono-and diacylglycerol lipase.     

Cardiac stem cells: translation to human studies

The discovery of multiple classes of cardiac progenitor cells in the adult mammalian heart has generated hope for their use as a therapeutic in heart failure. However, successful results from animal models have not always yielded similar findings in human studies. Recent Phase I/II trials of c-Kit (SCIPIO) and cardiosphere-based (CADUCEUS) cardiac progenitor cells have demonstrated safety and some therapeutic efficacy. Gaps remain in our understanding of the origins, function and relationships between the different progenitor cell families, many of which are heterogeneous populations with overlapping definitions. Another challenge lies in the limitations of small animal models in replicating the human heart. Cryopreserved human cardiac tissue provides a readily available source of cardiac progenitor cells and may help address these questions. We review important findings and relative unknowns of the main classes of cardiac progenitor cells, highlighting differences between animal and human studies     

Learned control of heart rate during dynamic exercise in nonhuman primates

The purpose of this study was to describe an animal model to test the relationships among the cardiovascular, pulmonary, and somatomotor command systems during exercise. Using operant conditioning, three chronically chaired monkeys (Macaca mulatta) were trained to exercise (to lift weights repeatedly), to attenuate their heart rate responses, and finally, both conditions were combined so that the animals were required to exercise and attenuate their heart rates. Heart rate, systolic and diastolic blood pressure, rate-pressure product, O2 and CO2 concentration in expired air, and number of weight lifts were recorded and compared between the two conditions, i.e., exercise only and combined exercise and heart rate slowing. In all animals heart rate increases in response to exercise were significantly less (P less than 0.05) during combined conditions than during exercise only: the mean heart rate increase was 41 beats/min less during combined sessions than during exercise only sessions for monkey 1, 13.5 beats/min less for monkey 2, and 9 beats/min less for monkey 3. Rate-pressure product showed a consistent difference across animals paralleling the heart rate differences. This acquired response did not involve other cardiovascular and pulmonary parameters, which did not change systematically across animals. However, the pattern of cardiovascular reactivity in relation to O2 consumption (linear regression of heart rate and systolic or diastolic blood pressure on change in O2 consumption over many experiments) was attenuated during combined sessions relative to exercise only experiments. The relative attenuation of heart rate during combined sessions also remained significant when both experimental conditions were equated on the basis of work done. Therefore, this animal model shows a dissociation of cardiovascular, somatomotor, and pulmonary effects of central command.     

A novel device for the automated administration of test compounds to laboratory animals

A prototype instrument is described that permits efficient administration of test compounds to laboratory animals by intubation. The system integrates a balance, a computer and a volumetric dispenser. Complete animal identification, weight and dose records are kept and may be interfaced with mainframe computers. A range of doses may be delivered from a single stock solution. No carryover is evident between doses. The system is accurate, precise and rugged. The system is cost effective relative to current manual gavage techniques and offers added safety for investigators handling toxic materials.     

Peculiarities of Cardiac Activity in the Crayfish Astacus astacus in Different Functional States

Analyzed are changes of temporal and amplitude characteristics of the cycles in animals in different functional states, using a non-invasive method of recording of cardiac activity in the adult noble crayfish Astacus astacus L. under laboratory conditions. It has been shown that the state of excitation in the crayfish after action of an intense stimulus lasts for a long time (more than 1 h) and can have no manifestations in some observed behavioral responses. Based only on the cardiac response (the heart rate), the real physiological state of the animal could be evaluated. Characteristic of the excited animal is a short-term response to the stimulus. In a high excitement of the animal (a high heart rate), significant transformations of the heart activity in response to other current stimuli may be barely noticeable. For the quiet animal, the response to a stimulus is longer than for the excited animal at the same stimulus intensity; for a comparative search for significant readjustments of the animal state, based on the heart activity parameters, the cardiograms typical of the quiet animal should be used. In the quiet animals, the cardiogram parameters change to a greater extent than in the excited ones. The quiet animals have longer diastole duration (DD) than the systole duration (SD). The diastole amplitude (DA) is higher than the systole amplitude (SA), and DA changes more markedly than SA. The healthy animals are characterized by equal values of DD and SD, sometimes by longer SD than DD, but, on the background of a continuing action, their values and the values of DA and SA become equal. There were noted a negative correlation between the systolic and diastolic phases by temporal parameters for healthy animals and an increase of the correlation significance in transition of the animal into the excited state. Based on the cardiovascular system response, the chief features of a shift of the functional crayfish state to pathological direction seem to include a stable heart rate reduction, a decrease of the heart contraction amplitude, a more frequent predominance of SD over DD, an increase of the means and the standard deviations of the parameters, especially of the cycle amplitudes. Changes of the sign and significance of correlation relations between inotropic and chronotropic parameters of cardiac activity in sick animals appear to indicate a disturbed mechanism of central coordination of the cardiovascular system work with its autonomic mechanisms. The results are discussed on the basis of known mechanisms of the heart activity control in Decapoda. The records of cardiac activity, such as laser light cardiograms (LLC), in testaceous invertebrates may be useful and interesting in studies on mechanisms and processes of internal control and management of the cardiovascular system activity of the animals.     

Effect of sex,hunger and relative body size on the use of ripple signals in the interactions among water striders Gerris latiabdominis

Water striders use ripple signals in aggressive interactions between individuals for access to food. We asked whether water striders produce ripple signals more frequently when they are hungrier and when the value of food resources is higher. We also asked if and how the use of signals depends on the size difference between interacting individuals. We found that females used ripple signals more often than males did. The experiment suggested that use of aggressive ripple signals is affected by hunger in females – the sex with high demands for food resources. Among females, but not males, we found out that the probability of using signals in response to the approaching intruder depended both on the degree of hunger and on the size of the focal animal relative to the size of the intruder. Before starvation, the probability of a female using a signal in an interaction with an intruder was higher when the individual's size was larger relative to the intruder. After starvation, the focal individuals were more likely to signal when their size was smaller relative to the intruder. The results are consistent with the idea that these signals may reveal information about the signalers weight or hunger level, and specific hypotheses are suggested for the future studies.