Dietary Patterns,Cognitive Decline,and Dementia: A Systematic Review

Nutrition is an important modifiable risk factor that plays a role in the strategy to prevent or delay the onset of dementia. Research on nutritional effects has until now mainly focused on the role of individual nutrients and bioactive components. However, the evidence for combined effects, such as multinutrient approaches, or a healthy dietary pattern, such as the Mediterranean diet, is growing. These approaches incorporate the complexity of the diet and possible interaction and synergy between nutrients. Over the past few years, dietary patterns have increasingly been investigated to better understand the link between diet, cognitive decline, and dementia. In this systematic review we provide an overview of the literature on human studies up to May 2014 that examined the role of dietary patterns (derived both a priori as well as a posteriori) in relation to cognitive decline or dementia. The results suggest that better adherence to a Mediterranean diet is associated with less cognitive decline, dementia, or Alzheimer disease, as shown by 4 of 6 cross-sectional studies, 6 of 12 longitudinal studies, 1 trial, and 3 meta-analyses. Other healthy dietary patterns, derived both a priori (e.g., Healthy Diet Indicator, Healthy Eating Index, and Program National Nutrition Santé guideline score) and a posteriori (e.g., factor analysis, cluster analysis, and reduced rank regression), were shown to be associated with reduced cognitive decline and/or a reduced risk of dementia as shown by all 6 cross-sectional studies and 6 of 8 longitudinal studies. More conclusive evidence is needed to reach more targeted and detailed guidelines to prevent or postpone cognitive decline.     

Milk lipid absorption and chylomicron production in the suckling rat

Structural correlates of milk lipid absorption and chylomicron production were studied in 10-day-old suckled rats. The gastric and duodenal contents and duodenal mucosae were examined with the light and electron microscopes. In the gastric lumen the milk lipid globule cores were smooth, circular and uniformly electron opaque. Many membranes and lamellar structures with a trilaminar and multilamellar appearance were adherent to the peripheries of the cores. In the central duodenal lumen the milk lipid globule cores were also smooth, circular and uniformly electron opaque. Very few milk lipid globules in the duodenal lumen showed adherent membranes or lamellae. Membrane fragments and lamellae were present in the lumen separate from the milk lipid globules. In the duodenal lumen between villi the milk lipid globules had multiple electron lucent indentations of the core. It is believed that the irregular peripheries of the milk lipid globule cores are the result of lipolysis within the duodenal lumen acting at the milk lipid globule surface. This lipolysis of triacylglycerol would produce amphiphilic lipids which may result in the electron lucent spaces at the milk lipid globule periphery. The absorptive epithelial cells along the length of the duodenal villus varied in structure relative to their position at the tip, middle, or base of the villus. Typical mid-villus epithelial cells contained lipid droplets averaging 0.3-μm diameter in the smooth and rough endoplasmic reticulum and in Golgi complexes in the apical cytoplasm. Villus tip and villus base cells contained large lipid droplets between 7–16 μm. Only a few 0.3-μm lipid droplets were present within these cells. These large lipid droplets appeared to be accumulations of triacylglycerol present in the apical cytoplasm associated with lamellar and membranous structures. Numerous chylomicrons were present between epithelial cells located in the middle region of the villus while significantly fewer chylomicrons were seen between epithelial cells at the tip and base of the villus. These observations suggest that the cells at the middle of the duodenal villus of suckling rats were more efficient in the production of chylomicron triacylglycerol derived from incoming milk triacylglycerol than cells at the tip and base of the villus.     

Isolated perfused dog lungs: A comparative stereologic comparison with normal dog lungs

Established stereologic techniques were used to evaluate the morphologic integrity of isolated dog lungs perfused with plasma for periods of 30 minutes, 1 hour and 2 hours. The morphometric data from the isolated lung preparations were compared to similar morphometric evaluations of dog lungs fixed immediately after removal from the thorax. In the isolated lungs capillary surface and volume densities were both substantially decreased. These estimations of capillary surface density provide a morphologic definition of capillary surface area which should be useful in the estimations of endothelial permeability in isolated lungs. This morphometrically defined decrease in capillary volume density was attributed, in part, to swelling of the endothelial cells. Alveolar surface density was also decreased and the type-I epithelial cells were increased in thickness. In both the endothelial and epithelial cells, cytoplasmic volume densities of the mitochondria and smooth endoplasmic reticulum were increased, while those of the rough endoplasmic reticulum and micropinocytotic vesicles were unchanged. The thickness of the interstitial compartment of the air-blood barrier and the volume densities of the peribronchial, peribronchiolar, and perivascular connective tissue sleeves were unchanged; there was no evidence of interstitial edema in the isolated lungs. These morphologic changes must be considered in the interpretation of physiologic studies which employ isolated perfused dog lung preparations.     

A peripheral 5-HT1D-like receptor involved in serotonergic induced hindlimb scratching in rats

The pharmacological characteristics of hindlimb scratching induced by serotonergic compounds were studied. We conclude that hindlimb scratching induced by serotonergic compounds is mediated by a serotonin1D (5-HT1D) or 5-HT1D-like receptor outside the blood-brain barrier because hindlimb scratching could be induced by s.c. injection of 5-methoxytryptamine (5-MeOT), 5-carboxamidotryptamine (5-CT), bufotenine, 5-hydroxytryptamine (5-HT) and tryptamine. These compounds have high affinity for 5-HT1A and 5-HT1D receptors. The 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), the 5-HT1C receptor agonist MK 212, and the mixed 5-HT1C/5-HT2 receptor agonists (dl)-1-(2,5 dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and quipazine did not induce hindlimb scratching. Rather, the latter compounds attenuated 5-MeOT-induced hindlimb scratching. The 5-HT releasing compounds fenfluramine and p-chloroamphetamine (PCA) inhibited whereas the 5-HT re-uptake inhibitors fluvoxamine and indalpine potentiated 5-MeOT-induced hindlimb scratching. 5-MeOT-induced hindlimb scratching could be inhibited dose dependently by the alpha 2-adrenoceptor blockers yohimbine and rauwolsince, which also have high affinity for 5-HT1D receptors, whereas the alpha 2-adrenoceptor blocker piperoxan only weakly counteracted hindlimb scratching. Haloperidol, apomorphine, morphine, clonidine and methiothepin strongly attenuated hindlimb scratching, atropine, naloxone and ICS 205930 attenuated it weakly whereas domperidone, methylatropine and mepyramine were inactive in doses up to 10 mg/kg. Hindlimb scratching induced by 5-MeOT was potentiated by the 5-HT receptor antagonists metergoline, methysergide, mesulergine, mianserin, ritanserin and xylamidine. Hindlimb scratching was not induced by i.c.v. injection of 5-MeOT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Polymyxin E-1 (colistin sulphate) (neuro-)intoxication in young ostriches ( Struthio camelus spp.)

Colistin (polymyxin E) is a cyclic polypeptide with a potent bactericidal action against most gramnegative bacilli. When used parenterally, polymyxins should be given with great care as they have a very small safety range, and easily induce neurotoxicity and nephrotoxicity. A dose of 39.5mg/kg body weight colistin sulphate injected subcutaneously induced rapid (within 1 to 3 h) mortality in young ostriches. Clinical signs of apathy, lethargy and hypotonia indicative of neurotoxicity of the compound were observed. At postmortem, vascular congestion of brain vessels was seen while, on histology, severe acute oedema was present in the epicardium and the intestinal serosa. Congestion of villi, swelling and vacuolization of the plexus ofAuerbach, as well as intermuscular and perivascular oedema of the heart, were also observed. In view of our observations in ostriches and in other species studied, a dose of >5mg/kg body weight polymyxin E is not considered safe for parenteral administration in ostriches.     

Cardiovascular autonomic regulation in preterm infants: the effect of atropine

To study cardiovascular autonomic control, we assessed the effect of atropine on heart rate (HR) and blood pressure (BP) variability in 12 preterm infants (range 26-32 wk) before intubation for respiratory insufficiency. Spectral power analysis of R-R interval and systolic BP (SBP) series were estimated in a low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.4-1.5 Hz) band and evaluated for a 10-min period before and a 10-min period after atropine sulfate (0.01 mg/kg). Baroreceptor reflex (BR) functioning was estimated using transfer function analysis at LF (coherence, gain, and phase). Atropine resulted in a significant 12% increase in steady-state HR (p < 0.01) and unchanged SBP. For R-R interval series, the total spectral power decreased 6-fold (p < 0.01), which was predominantly due to a reduction in the LF band (16-fold; p < 0.01). In contrast, we observed a significant increase (25%; p < 0.05) in total spectral power of SBP series partly as a result of an increase in HF power. The LF power of SBP series was not altered. The median LF transfer gain (BR sensitivity) between SBP and R-R interval decreased from 4.2 to 1.4 ms/mm Hg (p < 0.01) after atropine. The LF phase relationship (BP leads R-R interval fluctuations by approximately 4 s) was not changed after atropine. In conclusion, even in preterm infants in distress, atropine modulates HR and BP variability, suggesting that BR-mediated parasympathetic control of heart rate is of significance for cardiovascular control at that age.     

An ultrastructural morphometric comparison of the peripheral with the hilar air-blood barrier of dog lung

Excised and isolated perfused lungs are frequently used as models for studies of fluid flow and membrane transport. Regional variations of the air and blood vascular compartments of the lung have been recognized to result from gravitational effects. This ultrastructural morphometric study considered the components of the air-blood barriers of the peripheral and hilar regions of excised dog lungs. The lungs of three mongrel dogs were fixed by endotracheal instillation of glutaraldehyde and immersion in fixative. Stratified random sampling, point counting volumetry, and line intercept counts were used to determine the thicknesses of the air-blood barrier and the epithelial, interstitial, and endothelial compartments. Point counting volumetry also established the volume density of the alveolar spaces. The morphometric values for structures within the periphery were statistically compared to those within the hilar region by Student's t-test. Endotracheal and immersion fixation as used in this study, combined with stratified random sampling, equalized regional differences in the alveolar lumen volume and air-blood barrier thickness. With these conditions no significant differences in the volume densities of the epithelial and endothelial cells and the interstitium of the air-blood barrier were identified when those of the hilum were compared to those of the periphery.     

Re-endothelialization of microvascular carotid end-to-side anastomosis in the rat.

A carotid end-to-side anastomosis was performed on 25 male and female Wistar rats (mean weight 197.8 gm). The animals were sacrificed at time intervals varying from 0 to 21 days after the operation. The anastomosis was exposed, the aorta cannulated, and the animals perfused with a 2.5% buffered glutaraldehyde solution at a constant pressure of 80 mm Hg. The anastomoses were removed for scanning electron microscopic (SEM) and light microscopic studies. The SEM results indicate that after the acute platelet-fibrin reaction in the first 48 hours, the suture line itself becomes re-endothelialized after 4 days. On the stitches, however, a cellular population consisting of leukocytes transforming into flattened cells was seen after 2 days. The morphology of these cells and their role in the regeneration of endothelium is discussed. This study presents evidence supporting a blood-borne genesis of endothelial cells in vivo.