Jon J. Kabara

Antimicrobial lipids: natural and synthetic fatty acids and monoglycerides.

Over 40 natural or synthetic lipophilic compounds were screened for antimicrobial activity. Gram (+) bacteria and yeasts but not Gram (−) bacteria were affected by these agents. Epimino and selena fatty acids are more active than their corresponding straight chain unsubstituted fatty acids. The position of selenium influenced the antimicrobial activity of the fatty acid. The presence and position of a double or triple bond, usually an important factor in long chain fatty acids (>C14) had little or no effect in C11 fatty acids. Optimum antimicrobial activity was found for fatty acids and their corresponding monoglycerides when the chain length was C12. The dilaurin derivative was not active.

A critical review of brain cholesterol metabolism

Publisher Summary This chapter presents a critical review of brain cholesterol metabolism. Modern aspects of brain sterol metabolism are reviewed by Davison and Kabara. Consequently, for this review, the chapter emphasizes only the more recent concepts of brain cholesterol metabolism. To form a backdrop for the discussion of brain cholesterol metabolism, the anatomical and chemical changes taking place in the central nervous system (CNS) during growth and development are outlined in the chapter. Because sex, nutrition, precursor used, diurnal variation, etc., influence biosynthetic rates as measured, their influence should be considered in any developmental analysis of metabolic capacity within the CNS. Whole brain values obtained in the past from animals injected with a radioactive precursor did not reflect metabolism or changes in metabolism of anatomical areas, individual cells or organelles. Although accurate information is not available, conclusions based on such comparisons lead to statements in the literature which are very difficult to change, even in the face of new and more conclusive data.

Toxicological, bacteriocidal and fungicidal properties of fatty acids and some derivatives

The LD50 oral ingestion values for the common commercial fatty acids are in the range which are considered nontoxic; 24 hour primary skin irritation is considered positive for octanoic acid but negative for decanoic acid and upwards; 4 hour skin corrosivity is considered positive for decanoic acid and lower, negative for lauric acid and higher; eye irritation is considered positive for lauric acid and lower, negative for myristic acid and higher. Among the fatty acid derivatives that have well recognized bacteriocidal and fungicidal properties are undecanoic acid and its salts, sodium and zinc particularly, (athlete’s foot fungus), fatty amine quaternary salts, (general bacteriocide properties), fatty amide derivatives, and sodium salts of common fatty acids. The highly purified monoglyceride prepared from high C-12 fatty acid has unprecedented activity and sanitizing properties.

IN VITRO EFFECTS OF MONOLAURIN COMPOUNDS ON ENVELOPED RNA AND DNA VIRUSES

Monolaurin alone and monolaurin with tert‐butylhydroxyanisole (BHA), methylparaben, or sorbic acid were tested for in vitro virucidal activity against 14 human RNA and DNA enveloped viruses in cell culture. At concentrations of 1% additive in the reaction mixture for 1 h at 23°C, all viruses were reduced in infectivity by >99.9%. Monolaurin with BHA was the most effective virucidal agent in that it removed all measurable infectivity from all of the viruses tested. The compounds acted similarly on all the viruses and reduced infectivity by disintegrating the virus envelope.

Abnormal Levels of Urinary Catecholamines in Dystrophic Mice and Hamsters

Summary Twenty-four-hour urine was collected from normal and dystrophic mice and hamsters for catecholamine determinations. A new method of analysis was used whereby 3,4-dihydroxyphenylalanine (DOPA), dopamine (DA), norepinephrine (NE), and epinephrine (E) were measured simultaneously. The procedure is based on a combination of liquid-solid extraction, cation exchange chromatography, and controlled potential electrochemistry. The results of these experiments indicated that while DA levels were similar in both normal and pathological animal urine, DOPA levels decreased slightly in the dystrophic mouse but not the hamster, and NE and E levels in dystrophic groups were two and four times greater than normal in both species. The data supports the concept of biochemical alterations in tissue other than muscle. While not necessarily supportive to catecholamine abnormality as the primary cause of muscular dystrophy, the present data cast doubt that this disease is a primary muscle disease. This investigation was supported by grants from the National Institute of General Medical Sciences (GM 21580-01), the National Science Foundation (GP-42452X), and The Muscular Dystrophy Association of America, Inc.

Aminimides: II. Antimicrobial effect of short chain fatty acid derivatives

A new family of surfactants, aminimides, has been screened forin vitro antimicrobial activity. These compounds are active against both bacteria and yeast, activity being a function of chain length. Maximum activity for acetimide and acrylimide amine derivatives was extablished with chain lengths of C14–C16. Homologous compounds with lower or higher chain lengths were less active. While showing low antimicrobial activity against gram negative bacteria, mixtures containing C12 and C16 gave good activity against gram negative strains without losing gram positive activity. Aminimides gave low acute LD50’s (200–400 mg/kg) when tested in mice by intraperitoneal injection.

Effects of fatty acids on gap junctional communication: possible role in tumor promotion by dietary fat.

Dietary lipids, in particular unsaturated fat, promote the development of many experimental tumors. However, no mechanisms to fully explain these effects have been elucidated. Recent reports, which we summarize here, suggest a role for gap junction-mediated intercellular communication in the process of tumor promotion. We also review tumor-promoting effects of dietary fat on experimental, particularly mammary, carcinogenesis. Our main focus is to review recent data examining the inhibitory effects of unsaturated fatty acids on metabolic cooperation in Chinese hamster V79 cells. These data suggest that inhibition of junctional communication may be involved mechanistically in the promotion of tumors by high levels of dietary unsaturated fat. Finally, potential mechanisms by which unsaturated fatty acids inhibit metabolic cooperation are examined.

Lipophilic nerve sprouting factor(s) isolated from denervated muscle

Abstract This report confirmed earlier studies by other workers which suggested that collateral nerve sprouting in mammalian skeletal muscle is induced by factors released from denervated or atrophic muscle fibers. Crude lipid extracts of denervated but not of normal muscle were found to bring about histological evidence of significantly increased collateral nerve outgrowth when injected into normal muscles. Additional experiments indicated that separated non-polar and polar lipid fractions of muscle were less active. The injection of a chemically pure lipid, monlaurin, also caused significant sprouting.

Structure-function activity of azasterols and nitrogen-containing steroids

Thirty-nine nitrogen-containing steroids were tested against two gramnegative, five gram-positive, and two yeast organisms. Many of these steroids have been preiously reported to inhibit various metabolism processes involving sterol metabolism. While low minimal inhibitory concentration (MIC) values were recorded for sterol producing yeast, growth of bacteria which contain no sterols was also inhibited. Structure-function studies provided no relationship between biological activitity and hypocholesteremic effects of these azasteroids. A hypothesis put forward is that amino and azasteroids are effectors of membrane which, in the case of mitochondria, lead to changes in adenosine triphosphate levels and/or dehydrogenase activity. Their effects on sterol metabolism, there-fore, may be of secondary consideration.

Aminimides: I. Antimicrobial effect of some long chain fatty acid derivatives

Aminimides are a new class of surface active agents which have antimicrobial activity. These bipolar compounds have activity against both gran-positive and yeast organisms. Their activity against gram-negative organisms is low or absent. The acyl derivatives tested showed maximum activity at chain lengths of C14 and C16. Fatty acid derivatives, shorter (C16), were less active. Unsaturation was an important factor contributing to aminimide activity. Their low toxicity and wide spectrum of antimicrobial activity make aminimides ideal candidates for further investigation.