Preparation and properties of an antiplasma cell serum directed against a defined plasmacytoma cell population.

Heterologous antisera were prepared against a subpopulation of MOPC-104E tumor cells obtained by centrifugation on discontinuous BSA gradients as well as against cells from the whole tumor mass. The gradient-separated cells were more effective than the cells from the whole tumor mass in eliciting antisera not only higher titer, but also with greater specificity for plasmacytoma antigens. The unabsorbed antiserum prepared against the gradient-separated plasmacytoma population was cytotoxic for murine lymphoid cells, but not for murine kidney, liver, or brain cells. After in vitro absorption with murine thymocytes and removal of anti-immunoglobulin activity by affinity chromatography, the antiserum was found to be reactive against plasmacytoma cells, but was no longer cytotoxic for murine thymus or unstimulated spleen cells. This absorbed antiserum was also cytotoxic for LPS-, but not PHA- or Con A-stimulated normal murine spleen cells.     

Cardiomyocyte Antihypertrophic Effect of Adipose Tissue Conditioned Medium from Rats and Its Abrogation by Obesity is Mediated by the Leptin to Adiponectin Ratio

White adipocytes are known to function as endocrine organs by secreting a plethora of bioactive adipokines which can regulate cardiac function including the development of hypertrophy. We determined whether adipose tissue conditioned medium (ATCM) generated from the epididymal regions of normal rats can affect the hypertrophic response of cultured rat ventricular myocytes to endothelin-1 (ET-1) administration. Myocytes were treated with ET-1 (10 nM) for 24 hours in the absence or presence of increasing ATCM concentrations. ATCM supressed the hypertrophic response to ET-1 in a concentration-dependent manner, an effect enhanced by the leptin receptor antagonist and attenuated by an antibody against the adiponectin AdipoR1 receptor. Antihypertrophic effects were also observed with ATCM generated from perirenal-derived adipose tissue. However, this effect was absent in ATCM from adipose tissue harvested from corpulent JCR:LA-cp rats. Detailed analyses of adipokine content in ATCM from normal and corpulent rats revealed no differences in the majority of products assayed, although a significant increase in leptin concentrations concomitant with decreased adiponectin levels was observed, resulting in a 11 fold increase in the leptin to adiponectin ratio in ATCM from JCR:LA-cp. The antihypertrophic effect of ATCM was associated with increased phosphorylation of AMP-activated protein kinase (AMPK), an effect abrogated by the AdipoR1 antibody. Moreover, the antihypertrophic effect of ATCM was mimicked by an AMPK activator. There was no effect of ET-1 on mitogen-activated protein kinase (MAPK) activities 24 hour after its addition either in the presence or absence of ATCM. Our study suggests that adipose tissue from healthy subjects exerts antihypertrophic effects via an adiponectin–dependent pathway which is impaired in obesity, most likely due to adipocyte remodelling resulting in enhanced leptin and reduced adiponectin levels.     

Hypothermia and rewarming induced by surface and He-O2 inhalate temperature control.

Hypothermia and rewarming were induced by a combination of temperature-controlled surface and inhalate methods in rabbits. To facilitate respiratory heat exchange, inhalate-respiratory tract temperature and humidity gradients and thermal conductivity were increased. In addition, the upper respiratory tract was bypassed by an endotracheal tube. To aid in maintaining satisfactory circulatory dynamics, hypercapnia and hypoxia were induced. The combined surface and inhalate method produced a markedly more effective rate of cooling than surface temperature-controlled method alone. Animals survived core temperatures as low as 20.9 degrees C with no complications. The noninvasive simplicity of this method suggests its potential applicability in many clinical situations.     

Resistant Starch Alters the Microbiota-Gut Brain Axis: Implications for Dietary Modulation of Behavior

The increasing recognition that the gut microbiota plays a central role in behavior and cognition suggests that the manipulation of microbial taxa through diet may provide a means by which behavior may be altered in a reproducible and consistent manner in order to achieve a beneficial outcome for the host. Resistant starch continues to receive attention as a dietary intervention that can benefit the host through mechanisms that include altering the intestinal microbiota. Given the interest in dietary approaches to improve health, the aim of this study was to investigate whether the use of dietary resistant starch in mice to alter the gut microbiota also results in a change in behavior. Forty-eight 6 week-old male Swiss-Webster mice were randomly assigned to 3 treatment groups (n = 16 per group) and fed either a normal corn starch diet (NCS) or diets rich in resistant starches HA7 diet (HA7) or octenyl-succinate HA7 diet (OS-HA7) for 6 week and monitored for weight, behavior and fecal microbiota composition. Animals fed an HA7 diet displayed comparable weight gain over the feeding period to that recorded for NCS-fed animals while OS-HA7 displayed a lower weight gain as compared to either NCS or HA7 animals (ANOVA p = 0.0001; NCS:HA7 p = 0.244; HA7:OS-HA7 p<0.0001; NCS:OS-HA7 p<0.0001). Analysis of fecal microbiota using 16s rRNA gene taxonomic profiling revealed that each diet corresponded with a unique gut microbiota. The distribution of taxonomic classes was dynamic over the 6 week feeding period for each of the diets. At the end of the feeding periods, the distribution of taxa included statistically significant increases in members of the phylum Proteobacteria in OS-HA7 fed mice, while the Verrucomicrobia increased in HA7 fed mice over that of mice fed OS-HA7. At the class level, members of the class Bacilli decreased in the OS-HA7 fed group, and Actinobacteria, which includes the genus Bifidobacteria, was enriched in the HA7 fed group compared to the control diet. Behavioral analysis revealed that animals demonstrated profound anxiety-like behavior as observed by performance on the elevated-plus maze with time spent by the mice in the open arm (ANOVA p = 0.000; NCS:HA7 p = 0.004; NCS:OS-HA7 p = 1.000; HA7:OS-HA7 p = 0.0001) as well as entries in the open arm (ANOVA p = 0.039; NCS:HA7 p = 0.041; HA7:OS-HA7 p = 0.221; NCS:OS-HA7 p = 1.000). Open-field behavior, a measure of general locomotion and exploration, revealed statistically significant differences between groups in locomotion as a measure of transitions across quadrant boundaries. Additionally, the open-field assay revealed decreased exploration as well as decreased rearing in HA7 and OS-HA7 fed mice demonstrating a consistent pattern of increased anxiety-like behavior among these groups. Critically, behavior was not correlated with weight. These results indicate that diets based on resistant starch can be utilized to produce quantifiable changes in the gut microbiota and should be useful to “dial-in” a specific microbiome that is unique to a particular starch composition. However, undesirable effects can also be associated with resistant starch, including lack of weight gain and increased anxiety-like behaviors. These observations warrant careful consideration when developing diets rich in resistant starch in humans and animal models.     

DISPERSAL OF AQUATIC ORGANISMS: VIABILITY OF SEEDS RECOVERED FROM THE DROPPINGS OF CAPTIVE KILLDEER AND MALLARD DUCKS

Seeds of aquatic and semiaquatic angiosperms were fed to two representative waterbirds: killdeer (Charadrius vociferus) and mallard ducks (Anas platyrhynchos). The viability and maximum period of retention for seeds recovered from the droppings were determined. Results indicate that resistance of the seeds to avian digestive processes depends both upon the nature of the seed coat and the species of bird through which they pass. Periods of maximum retention, greater in killdeer than in mallard ducks, were much longer than had previously been supposed. Plants with highly resistant seeds are for the most part of wide geographic distribution suggesting that the extensive range of many aquatic plants can be accredited, at least in part, to their adaptation to internal transport by birds.     

A histochemical and ultrastructural study of the development of the propulsive musculature of the brown trout, Salmo trutta L., in relation to its swimming behaviour

The differentiation of the myotomal muscle types in the propulsive musculature of Salmo trutta has been investigated histochemically and ultrastructurally from late embryonic to free-swimming fish at 5° months post fertilisation and related to observed changes in swimming behaviour. A histochemical and ultrastructural characterisation was also made of the major myotomal muscle fibre types in fingerling and yearling S. trutta . Two distinct populations of muscle cell types can be recognised prior to hatching. The early development of the white fibre population is related to the short, burst-type swimming activity at early stages. The later increase in the development of the red fibre population is directly related to the appearance of sustained swimming activity. The swimming performance of freeswimming alevins has been investigated and the results are discussed in comparison to adult fish.