Consumption of a High-Fat Diet Alters Perineuronal Nets in the Prefrontal Cortex.

A key factor in the development of obesity is the overconsumption of fatty foods, which, in addition to facilitating weight gain, alters neuronal structures within brain reward circuitry. Our previous work demonstrates that sustained consumption of a high-fat diet (HFD) attenuates spine density in the prefrontal cortex (PFC). Whether HFD promotes structural adaptation among inhibitory cells of the PFC is presently unknown. One structure of interest is the perineuronal net (PNN), a specialized extracellular matrix surrounding, primarily, parvalbumin-containing GABAergic interneurons. PNNs contribute to synaptic stabilization, protect against oxidative stress, regulate the ionic microenvironment within cells, and modulate regional excitatory output. To examine diet-induced changes in PNNs, we maintained rats on one of three dietary conditions for 21 days: ad libitum chow, ad libitum 60% high fat (HF-AL), or limited-access calorically matched high fat (HF-CM), which produced no significant change in weight gain or adiposity with respect to chow controls. The PNN "number" and intensity were then quantified in the prelimbic (PL-PFC), infralimbic (IL-PFC), and ventral orbitofrontal cortex (OFC) using Wisteria floribunda agglutinin (WFA). Our results demonstrated that fat exposure, independent of weight gain, induced a robust decrease in the PNN intensity in the PL-PFC and OFC and a decrease in the PNN number in the OFC.

Divalent cation-dependent interaction of sulfated polysaccharides with phosphatidylcholine and mixed phosphatidylcholine/phosphatidylglycerol liposomes.

The Ca(2+)-dependent interaction of various polyanionic polysaccharides (chondroitin sulfate, heparin, dextran sulfate, beta-cyclodextrin sulfate, hyaluronic acid and carboxymethyldextran) with multilamellar dimyristoyl phosphatidylcholine (DMPC) liposomes was investigated by calorimetric and fluorescence spectroscopic measurements. It was found that an observed polysaccharide-induced phospholipid phase separation depends on the density of the sulfate groups along the polysaccharide chain independent of the presence of additional carboxyl groups. The phase separation resulting from the drastic dehydration of the covered membrane regions is monitored by the upward shift of the lipid phase transition and by the blue shift of the emission spectrum of a headgroup-dansylated phosphatidylethanolamine (DPE). This shift is only observable if the required polysaccharide chain length contains at least three glycosyl units. The Ca(2+)-mediated interaction of dextran sulfate with various phosphatidylcholines, differing in their compressibility, showed the maximal difference between the phase transition temperatures of the lipid phase covered by the polysaccharide and the uneffected lipid domains for dielaidinoyl phosphatidylcholine (DEPC), the most compressible phospholipid investigated here. Mixed negatively charged DMPC/dimyristoyl phosphatidylglycerol (DMPG) liposomes were found to compete with the likewise negatively charged dextran sulfate for the binding of Ca2+. At excess Ca2+ concentrations, the binding of the polysaccharide was strengthened, compared to pure DMPC liposomes. The monovalent cation sodium, was able to inhibit the interaction between the membrane surface and dextran sulfate. Various divalent cations were found to mediate the interaction, depending on their ionic radii and electron configuration. Within the second group of the periodic system Ca2+ is the most effective ion. However, within the horizontal forth period the ability to bind sulfated dextran to membrane surfaces decreases from Ca2+ to Ni2+, but then increases again if Cu2+ or Zn2+ was used as the mediating ion.

Pathologic changes in the cardiac interstitium of mice infected with encephalomyocarditis virus.

Patients with myocarditis often develop dilated cardiomyopathy and congestive heart failure. Histologically, myocarditis is manifested by rare foci of myocyte necrosis with interstitial inflammation, while cardiomyopathy is characterized by diffuse interstitial fibrosis, myocyte hypertrophy, and an absence of active interstitial inflammation. The relationship between myocardial inflammation and interstitial fibrosis is poorly understood. This relationship was examined in mice that developed a diffuse interstitial inflammation of the heart over a period of 21 days following infection with encephalomyocarditis virus. Typical early lesions (day 7) included focal zones of myocytolysis containing mononuclear and polymorphonuclear inflammatory cells that were associated with the focal loss of reticular fibers. Later pathology (days 14-21) was characterized by a sparse, diffuse interstitial myocarditis with little ongoing necrosis. Changes within the myocardial interstitium remote from healing necrotic foci were marked by reticular fiber thickening and disorganization, often associated with pleomorphic fibroblasts. Reticulin fiber deposition was quantitatively increased in sparsely inflamed regions of hearts from infected animals as compared to noninflamed regions from the same hearts (p < 0.005) or hearts of control animals (p < 0.001). Scanning electron microscopy revealed interstitial changes that were more extensive than indicated by routine staining with hematoxylin and eosin for Masson's trichrome. The progressive changes within the cardiac interstitium during the development of postmyocarditic cardiomyopathy suggest that direct viral infection of fibroblasts or an interaction between the interstitium and inflammatory cells and their secreted products may contribute to pathologic changes within the interstitial collagen matrix.

In vivo deposition of myosin-specific autoantibodies in the hearts of mice with experimental autoimmune myocarditis.

Experimental autoimmune myocarditis (EAM) is elicited in certain strains of mice by immunizing with mouse cardiac myosin. Concomitant with the onset of myocardial inflammation is the induction of circulating IgG antibodies to myosin. To further examine the role of myosin in disease, both EAM-susceptible (A/J) and EAM-resistant (B10.A) mice were immunized with myosin emulsified in CFA and examined for myocardial inflammation and IgG deposition. Myocarditis was common in susceptible, but not resistant strain mice. IgG deposition was extensive in A/J mice, but modest in B10.A mice, when compared to controls given adjuvant alone. Localization was independent of inflammatory or necrotic lesions. A spot ELISA indicated that antimyosin IgG antibody-secreting cells were present in the myocardial infiltrate and likely contributed to antibody localization. Antibody was eluted from the hearts of immunized animals and found to react strongly with normal heart tissue by indirect immunohistochemistry. This reactivity was not completely absorbed by skeletal muscle, indicating that some of the antibody was heart-specific. Western immunostaining demonstrated that eluates from immunized A/J and B10.A mice possessed anti-myosin antibody activity; similar reactivity was not observed in eluates from control mice of either strain. Comparison of heart reactivity with syngeneic and allogeneic tissue suggests that although myosin immunization elicits homologous antibody in both strains, each may recognize distinct epitopes. These findings strongly suggest that cardiac myosin or a myosin-like determinant is expressed on the surface of normal mouse myocytes.

Heart-specific autoantibodies can be eluted from the hearts of Coxsackievirus B3-infected mice.

This study was undertaken to determine if immunoglobulin G (IgG) antibodies could be eluted from the hearts of mice with Coxsackievirus B3-induced autoimmune myocarditis and to characterize the immunoreactivity of any elutable autoantibodies. Susceptible (A/J) and resistant (B10.A) mice were administered the virus or the control treatment and killed at various times after treatment. Acid eluates from pooled heart tissue from each treatment group and each time were tested for IgG reactivity with normal heart tissue by immunohistochemistry and with normal heart extracts by Western immunostaining. Eluates from infected A/J mice reacted strongly with syngeneic heart and modestly with syngeneic skeletal muscle tissue. Eluates from infected B10.A or control mice of either strain exhibited little reactivity with either tissue. Tissue reactivity was similar when allogeneic tissue was used as the substrate. Eluates from infected A/J mice recognized the heavy chain of cardiac myosin and several other cardiac antigens by Western immunostaining while eluates from the other treatment groups exhibited little or no reactivity with any normal heart constituents. These results indicate that in vivo IgG deposition occurs in the hearts of mice with post-infectious autoimmune myocarditis and that the specificity of these antibodies is similar to that reported for serum from animals with this disease. The mechanism(s) leading to myocardial IgG deposition and its possible role in pathogenesis remain to be elucidated.

Spectroscopic studies on the metal-ion-binding sites of Co2(+)-substituted D-xylose isomerase from Streptomyces rubiginosus.

The coordination sphere of the two metal-binding sites/subunit of the homotetrameric D-xylose isomerase from Streptomyces rubiginosus has been probed by the investigation of the Co2(+)-substituted enzyme using electronic absorption, CD and magnetic circular dichroic spectroscopies in the visible region. The spectrum of the high-affinity site (B site) has an absorption coefficient, epsilon 545, of 18 M-1 cm-1, indicating a distorted octahedral complex geometry. The spectrum of the low-affinity site (A site) shows two absorption maxima at 505 nm and 586 nm with epsilon values of 170 M-1 cm-1 and 240 M-1 cm-1, respectively, which indicates a distorted tetrahedral or pentacoordinated complex structure as also observed for the enzyme from Streptomyces violaceoruber [Callens et al. (1988) Biochem. J. 250, 285-290] having the same feature but lower epsilon values. The first 4 mol Co2+ added/mol apoenzyme occupy both sites nearly equally. Subsequently the Co2+ located in the A site slowly moves into the B site. After equilibrium is reached, the next 4 mol Co2+/mol again occupy the A site with its typical spectrum, restoring full activity. Addition of 4 mol Cd2+ or Pb2+/mol Co4-loaded derivative displaces the Co2+ from the B site to form the Pb4/Co4 derivative containing Co2+ in the A site, reducing activity fourfold while the Pb4/Pb4 species is completely inactive. In contrast, Eu3+ displaces Co2+ preferentially from the A site. Thus, the high- and low-affinity sites may be different for different cations. After addition of the substrates D-xylose, D-glucose and D-fructose and the inhibitor xylitol the intense Co2+ A-site spectrum of both the active Co4/Co4 derivative and the less active Pb4/PCo4 derivative decreases, indicating that these compounds are bound to the A site, changing the distorted tetrahedral or pentacoordinated symmetry there to a distorted octahedral complex geometry.

Modification of the vermont test for monitoring fat adulteration of dairy products.

The Vermont test was developed for the routine screening of dairy products for vegetable fat adulteration. A slight modification of the test procedure made it more rapid and reduced costs. Gas-liquid chromatographic analysis of saponified fatty acids in the first and second Mojonnier extractions were proportional; thus, only the first extraction was needed to determine the purity of a milk lipid sample. This modification saves about 8 min/series of four samples and conserves 48% of the volume of organic solvents necessary to perform the classical Mojonnier extraction.

Precision and sensitivity of a test for vegetable fat adulteration of milk fat.

A test for routine screening of Mozzarella cheese and butter for vegetable fat adulteration is described. Fat is extracted and saponified. The potassium salts of the fatty acids are measured through direct gas chromatographic analysis. A ratio, calculated from the concentrations of butyric and oleic acids, is used to evaluate the purity of a sample. The test offers good precision and can detect less than 10% partially hydrogenated vegetable fat.

The symbolic and object play of children with autism: a review.

The unique characteristics of autistic children's symbolic and object play are presented and discussed in the context of a literature review covering research since 1964. Several theoretical issues are highlighted: the relationship of play in facilitating language and cognition, play as an intervention, and play as an assessment tool. Difficulties in research methodology due to pooling autistic and schizophrenic subject are raised, as well as possible difficulties inherent in ignoring severity levels within the autistic population. The appropriateness of play therapy is questioned, and evidence is presented to provide encouragement for further inquiry into the study of autistic play.

The Lich-Gregoir antireflux plasty: experiences with 371 children.

The Lich-Gregoir antireflux procedure is a simple and safe method for the treatment of primary reflux of all grades if the ureter is not grossly dilated on the excretory urogram. Reflux was cured in 97.7 per cent of 429 ureters in 371 children. A stenosis of the terminal ureter requiring reimplantation occurred in 0.5 per cent. The over-all rate of reinterventions was 3.7 per cent. This low complication rate makes surgical correction of reflux advisable if urinary tract infection and primary reflux cannot be eradicated by continuous antimicrobial therapy within 6 months.