Chemosensory Disorders and Nutrition
Alan R. Hirsch in Nutrition and Sensation, 2023
In an open label, followed by a double-blind trial of phosphatidylcholine at nine grams a day for three months, mixed results were seen (Hirsch and Dougherty 1992). A 40% improvement on the open-label study was followed by a negative result on the double-blind study. The double-blind study design is noteworthy due to the conclusions after two months. Experimental subjects on the active agent dropped out of the double-blind trial with phosphatidylcholine as a result of their severe dislike of the taste of the phosphatidylcholine. Since none of the patients voiced this complaint initially, it seems possible that their sense of smell, and therefore of flavor, improved during treatment, making them more aware of the taste of the active agent. None of the control subjects who dropped out mentioned the licorice taste as a reason (Hirsch, Dougherty, Aranda, Vanderbilt, and Weclaw 1996). Accordingly, in those with idiopathic hyposmia or anosmia, a three-month trial of phosphatidylcholine (Phoschol) at nine grams per day in three divided doses may be beneficial.
Nano-Sized CT Contrast Agents *
Valerio Voliani in Nanomaterials and Neoplasms, 2021
Because of the differences in chemical potential, the incorporated contrast agents can diffuse out through the membrane [51]. Since the permeability of the membrane is related to its rigidity or crystallinity, cholesterol is usually added when the liposomes are prepared [63]. Cholesterol is also known to be critical for liposome stability. Liposomes without cholesterol are destabilized by high-density lipoproteins (HDL) during circulation. In addition, phospholipid components also play important roles for stability of liposomes [64]. Liposomes containing phospholipids with a phase transition temperature higher than 37°C (such as dioleoylphosphatidylcholine) have more rigid membranes. To avoid leakage of iodinated molecules, iodine was covalently incorporated into the lipid bilayer [65]. An iodinated lipid was prepared by modification of phosphatidylcholine. The size of the liposome containing diiodophosphatidylcholine was ranged from 50 to 150 nm. The iodine concentration of the liposome was 28%, which was further increased by incorporation of iohexol at the aqueous core.
Structures and Properties of Self-Assembled Phospholipids in Excess Water
E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson in Phospholipid-Binding Antibodies, 2020
Each class of the above mentioned diacyl phosphoglycerides refers to a family of lipid molecules with the same headgroup, but with different fatty acid composition in the hydrophobic tail. The complexity within each class can be demonstrated by the 13 major molecular species of phosphatidylcholine found in the human erythrocyte membrane,14 most of them having different fatty acyl chains at the sn-l and sn-2 carbons of the glycerol backbone (Table 1). It is important to note that for most of the major species shown in Table 1 a saturated fatty acyl chain is esterfied at the sn-1 position, and an unsaturated acyl chain at the sn-2 position. It should also be mentioned that the commonly observed unsaturated bond in most phospholipids is the double bond with a cis configuration. The position of the cis-double bond along the acyl chain most frequently occurs between carbons 9 and 10 from the carboxyl end. If two or more cis-double bonds are present, then these double bonds are always separated from each other by one methylene group. Some of the saturated and unsaturated fatty acids found in membrane phospholipids and their nomenclatures are given in Table 2.
Nuts consumption and hypertension risks in children: a mediating role of circulating lipid metabolites
Published in Clinical and Experimental Hypertension, 2023
Liu Qin, Yanling Ren, Lan Chen, Ye Feng, Shunqing Luo, Ping Zhang, Wei Zhang, Xiaohua Liang
In addition to traditional lipid risk factors [LDL-C and very low-density lipoprotein cholesterol (VLDL-C), TGs], alterations in the composition of other circulatory lipid classes may be associated with hypertension (22). For example, α‐linolenic acid (ALA) has been considered a reliable blood biomarker of nut consumption since walnuts have a high ALA content in comparison to other foods (23). A population-based study of 990 adolescents identified several novel glycerophosphocholine metabolites using mass spectrometry (MS) analysis that was associated with multiple cardiovascular disease (CVD) risk factors (24). Significantly, phosphatidylcholine (PC) 16:0/2:0 was negatively associated with blood pressure level. However, it is not clear whether these metabolites are beneficial for the cardiovascular system of children.
Ultrastructural analysis of the intracellular surfactant in lungs of healthy and ovalbumin sensitized and challenged Brown Norway rats
Published in Experimental Lung Research, 2023
Andreas Schmiedl, Stefanie Frank, Thomas Tschernig, Jens M. Hohlfeld
Lb secretion is regulated by chemical stimuli, such as β-agonists, cholinergic agonists and adenosine, or physical stimuli, such as ventilation.16,62 Furthermore, components of the allergic inflammatory metabolism, such as IL-1 or TNF-α,30,34,63 are also able to influence the secretion of surfactant.16 Thus, disturbances of synthesis, storage and secretion are conceivable. Liu et al. proved a decreased synthesis, storage and activity of phospholipids, measured on isolated AEII.64 They found a significant decrease in cellular phospholipids and phosphatidylcholine synthesis in AEII isolated from immunized and challenged guinea-pigs. The phospholipid content was 33% of control values and the rate of phosphatidylcholine synthesis less than 35%.64 However, these biochemical alterations are not accompanied by clearly visible changes in the morphological correlates of the intracellular surfactant pool.
A tale of nucleic acid–ionizable lipid nanoparticles: Design and manufacturing technology and advancement
Published in Expert Opinion on Drug Delivery, 2023
Phosphatidylcholine (PCs) is an essential natural component of biological membranes. The cylindrical geometry of PC facilitates the development of the bilayer phase [62]. Saturated 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) has a high melting temperature and is useful for the formation of more stable ionizable LNPs. Unsaturated ionizable lipids and saturated helper lipids create distinct membrane domains that stabilize and protect nucleic acid during endosomal escape [63]. The high temperature of the DSPC can maintain the structure of nucleic acid-ionizable LNPs during endosomal escape as well as colloidal storage. The addition of cholesterol stabilizes bilayers structure of DSPC helper lipids. For cellular stability and transfection activity of the ionizable LNPs, DSPC-based formulations are found to be better than DOPE-based formulations [64,65]. DSPC was utilized in the preparation of the Covid −19 vaccines, Comirnaty and Spikevax.
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