Lipoids

The actual mechanism or process involved in the operation of smelling is not exactly known. The most important investigation in this direction is that of Backmann. He observed that in order that a substance may be odorous it must be sufficiently soluble in both water and in the lipoid fats of the nose cells. The odours of the saturated aliphatic alcohols first increase as the molecular weight increases and then decrease. The lower alcohols are comparatively odourless because of their low degree of solubility in the lipoid fats, while on the other hand the highest members are odourless because of their insolubility in water. The intermediate alcohols which are soluble in both fats and water have powerful odours. Backmann used olive oil in his experiments as a substitute for the lipoid fats. 

In this connection it is interesting to recall Kremer s experiments. By means of a spectroscopic method, Kremer demonstrated that when air saturated with an odoriferous substance such as pyridine or camphor is bubbled through a liquid containing a lipoid—such as a suspension of lecithin of a fatty animal tissue in Ringer s solution—more of the odoriferous substance is adsorbed than when the saturated air passes through water only. 

It appears from this that some sort of reaction, physical or chemical, takes place between odoriferous bodies and the lipoid fats of the... 

It seems likely that the sequence of events in the process of smelling is, after the odoriferous substance has reached the nostrils, first for the substance to dissolve in the aqueous outer layer, thence passing to the lipoid fats, wherein an addition reaction takes place, causing a change of energy which produces a sensation perceptible to the nervous centre. 

It will be realised that the strength of an odour may suffer successive diminutions in the process of smelling. It will be governed firstly, by the vapour pressure. of the odoriferous body, secondly, by the degree of solubility of the substance in water, thirdly, to its relative solubility in the lipoid fats with respect to that in water, and, lastly, to the speed of the chemical reaction. To a less extent the type of odour is similarly governed and this may account for the many shades of odour that exist. It is obvious that too much importance must not be placed on the chemical aspect of the problem, especially as regards the strength of an odour. 

Fettalkohol, m. fat alcohol, fett-arm, a. poor in fat. -aromatisch, a. aliphatic-aromatic. -artig, a. fat-like, fatty, lipoid. 

Hematologic diseases autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, pernicous anemia Kidney disease Goodpasture syndrom, lipoid nephroses, minimal change glomerulonephritis Diseases of the gastrointestinal tract autoimmune chronic active hepatitis, autoimmune atrophic gastritis, Crohn s disease, ulcerative colitis... 

The Constitution of a Lipoid-bound Polysaccharide from M. tuberculosis (Human strain), N. Haworth, P. W. Kent, and M. Stacey, J. Chem. Soc., (1948) 1220-1224. 

Jiskoot, W., Teerlink, T., Van Hoof, M. M. M., Bartels, K., Kanhai, V., CrommeUn, D. J. A., and Beuvery, E. C. (1986b). Immunogenic activity of gonococcal protein I in mice with three different lipoidal adjuvants delivered in liposomes and in complexes, Inf. Immun.. 54. 333-338. 

Uncouplers (eg, dinitrophenol) are amphipathic (Chapter 14) and increase the petmeabihty of the lipoid inner mitochondrial membrane to protons (Figure 12—8), thus teducing the electtochemical potential and shott-citcuiting the ATP synthase. In this way, oxidation can proceed without phosphotylation. 

The polyisoprenoids dolichol (Figure 14-20 and Chapter 47) and ubiquinone (Figure 12-5) are formed from farnesyl diphosphate by the further addition of up to 16 (dolichol) or 3-7 (ubiquinone) isopentenyl diphosphate residues, respectively. Some GTP-binding proteins in the cell membrane are prenylated with farnesyl or geranylgeranyl (20 carbon) residues. Protein prenylation is believed to facilitate the anchoring of proteins into lipoid membranes and may also be involved in protein-protein interactions and membrane-associated protein trafficking. 

Lubricant laxatives work by coating the stool, which allows it to be expelled more easily. The oily film covering the stool also keeps the stool from losing its water to intestinal reabsorption processes. Mineral oil (liquid petrolatum) is a non-prescription heavy oil that should be used with caution, if at all, since it may be aspirated into the lungs and cause lipoid pneumonia. This is of particular concern in the young or the elderly. 

It is generally agreed that the contact-insecticidal activity of the DDT type of compound depends on at least one toxic component and the CC13 group or some other lipoid-soluble group for penetration. Beyond this point, there is a lack of agreement as to the exact mechanism by which the contact insecticides exert their action. 

Although a lipoid-soluble group characterizes many contact insecticides, simple oil-solubility of a compound is not always a criterion of activity. Busvine (14) tested a series of DDT analogs and found that solubility in oil was not essential to activity. Kirkwood... 

Mineral Oil Hydraulic Fluids. Lipoid pneumonia with marked interstitial pneumonitis and pulmonary fibrosis was observed in a child accidentally ingesting a lethal dose of automotive transmission fluid (Perrot and Palmer 1992). Although the exact composition of the hydraulic fluid was not reported, it is assumed to be a mineral oil hydraulic fluid because automotive transmission fluids typically contain... 

Oil accumulation in the lungs after long-term or high-level exposure to aerosols of polyalphaolefin may be a concern, based on observations of lipoid pneumonia in humans after prolonged intranasal application of mineral oil mists (Lushbaugh 1950) and the physical and chemical similarities between mineral oil and polyalphaolefins (i.e., both are composed predominately of aliphatic hydrocarbons). 

Based on physical and chemical similarities between mineral oil and polyalphaolefins, oil accumulation in the lung (and subsequent lipoid pneumonia) may occur following the ingestion of polyalphaolefin hydraulic fluids due to aspiration, and that distribution of polyalphaolefins to the liver and fatty tissues may occur to some degree (see discussion for distribution of mineral oil hydraulic fluids). 

Mineral Oil Hydraulic Fluids. Only one report was located regarding death in humans following exposure to mineral oil hydraulic fluids. A 14-month-old boy ingested 5-10 cc of a mineral oil hydraulic fluid and died 4 weeks later after developing pneumonia (Perrot and Palmer 1992). Postmortem analysis revealed edema, hemorrhages, and lipoid/oil droplets in the lungs. The attending physicians believed that the development of lipoid pneumonia with marked interstitial pneumonitis eventually led to death. 

Mineral Oil Hydraulic Fluids. There is a paucity of data on respiratory effects following inhalation, oral, or dermal exposure to mineral oil hydraulic fluids. The only available information for humans comes from a case report of a child ingesting a lethal dose of an automotive transmission fluid, which was most likely a mineral oil hydraulic fluid. Lipoid pneumonia with marked fibrosis was observed (Perrot and Palmer... 

Perrot LJ, Palmer H. 1992. Fatal hydrocarbon lipoid pneumonia and pneumonitis secondary to automatic transmission fluid ingestion. J Forensic Sci 37 1422-1427. 

Another method of delivery of drug to the anterior segment of the eye that has proved successful is prodrug administration [144]. Since the corneal surface presents an effective lipoidal barrier, especially to hydrophilic compounds, it seems reasonable that a prodrug that is more lipophilic than the parent drug will be more successful in penetrating this barrier. 

Fernandez, M. S. Fromherz, P., Lipoid pH indicators as probes of electrical potential and polarity in micelles, J. Phys. Chem. 81, 1755-1761 (1977). 

Caron, K. M., Soo, S. C., Wetsel, W. C., Stocco, D. M., Clark, B. J., and Parker, K. L. 1997. Targeted disruption of the mouse gene encoding steroidogenic acute regulatory protein provides insights into congenital lipoid adrenal hyperplasia. Proc. Natl. Acad. Sci. U.S.A., 94(21) 11540-11545. 

Mineral oil may be absorbed systemically and cause a foreign-body reaction in lymphoid tissue. Also, in debilitated or recumbent patients, mineral oil may be aspirated, causing lipoid pneumonia. 

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