Fatty acid composition of adipose tissue in humans: differences between subcutaneous sites

We compared the fatty acid composition of adipose tissue from three different sites, one deep-seated site (perirenal) and two subcutaneous sites (abdominal and buttock), in 143 autopsied adult humans aged 24-61 y. The proportion of saturated fatty acids was highest in the perirenal adipose tissue and lowest in buttock adipose tissue. The proportions of monounsaturated fatty acids in the three sites were in the reverse order. Linoleic and linolenic acids were similar in the three adipose-tissue sites, an important finding for those concerned about the essential fatty acids, which are solely derived from the diet. The results clearly show that the fatty acid composition of the two subcutaneous fat depots differ significantly. We conclude that abdominal fat is more saturated than buttock fat.

De novo biosynthesis of polyunsaturated fatty acids in the cockroach Periplaneta americana

The de novo biosynthesis of 6,9,12-linolenic acid, 11,14-eicosadienoic acid, 5,11,14-eicosatrienoic acid, and arachidonic acid was demonstrated in adult female cockroaches, Periplaneta americana. These four polyunsaturated fatty acids (PUFA) were present primarily in the phospholipid (PL) fraction of both males and females. They were purified by AgNO3 thin-layer chromatography and high pressure liquid chromatography. The double bond positions of the major isomer of eicosatrienoic acid were shown to be at the delta 5,11,14 positions by gas chromatography-mass spectrometry (GC-MS) of both methoxy and epoxide derivatives and gas-liquid chromatography (GLC) and GC-MS of ozonolysis products. The other PUFAs cochromatographed with standards on both packed and capillary GLC columns. The in vivo incorporation of [1-14C]acetate into 5,11,14-eicosatrienoic acid, 11,14-eicosadienoic acid, 6,9,12-linolenic acid, and arachidonic acid was demonstrated by radio-GLC and radio-HPLC and for 5,11,14-eicosatrienoic acid by radio-GLC of ozonolysis products. The latter technique clearly demonstrated that the entire eicosatrienoic acid molecule was labeled. Thoracic tissue contained the highest amount of radiolabeled 5,11,14-eicosatrienoic acid (1.6% of total radioactivity incorporated into PL) while radiolabeled 11,14-eicosadienoic acid was found primarily in abdominal epidermal tissue (2% of total radioactivity incorporated into PL). Radiolabeled arachidonic and 6,9,12-linolenic acids comprised 0.1 and 0.02%, respectively, of the total radioactivity in the PL fraction. These data document the de novo biosynthesis of di-, tri-, and tetraunsaturated fatty acids in the American cockroach, and indicate that this animal can desaturate on both sides of the delta 9 double bond of oleic acid.

The influence of body fat distribution on the incidence of diabetes mellitus. 13.5 years of follow-up of the participants in the study of men born in 1913

In a prospective study of risk factors for ischemic heart disease, 792 54-yr-old men selected by year of birth (1913) and residence in Göteborg, Sweden, agreed to attend for questioning and a number of anthropometric and other measurements in 1967. Thirteen and one-half years later, these baseline findings were reviewed in relation to the number of men who had subsequently developed diabetes mellitus. This analysis focused on the importance of abdominal adipose tissue distribution, measured as the waist-to-hip circumference ratio, as a predictor for development of diabetes. Even when the confounding effect of body mass index, as a measure of the total body fat mass, was accounted for, the waist-to-hip ratio was positively and significantly associated with the risk for diabetes. These results from a prospective study strongly support previous cross-sectional findings indicating that not only the degree of obesity but also the localization of fat is a risk factor for diabetes.

Sclerotin and lipid in the waterproofing of the insect cuticle

In all the cuticles studied waterproofing is effected by extracuticular material, a mixture of sclerotin precursors and lipids, exuded from the tubular filaments of the pore canals. In Rhodnius larval abdomen it is a layer of thickness similar to the outer epicuticle, believed to be composed of 'sclerotin' and wax, in Schistocerca larval sternal cuticle and in Carausius sternal cuticle it is similar. In Tenebrio adult sternal cuticle of the abdomen, in both the extracuticular exudation and the contents of the distal endings of the tubular filaments, the wax component is obscured by hard 'sclerotin'. In Manduca larva a very thin layer of 'sclerotin' and wax is covered by an irregular wax layer, average 0.75 micron, twice the thickness of the inner epicuticle. In Periplaneta and Blattella the abdominal cuticle is covered by a soft waxy layer, often about 1 micron thick, which is mixed with argentaffin material. Below this is a very thin waterproof layer of wax and 'sclerotin' continuous with the contents of the tubular filaments, which is readily removed by adsorptive dusts. In Apis adult abdominal terga free wax plus sclerotin precursors form a thin layer which is known to be removed by adsorptive dusts. In Calliphora larva there is a very thin layer of the usual mixed wax and sclerotin and below this a thick (0.5 micron) layer, lipid staining and strongly osmiophil, likewise extracuticular and exuded from the epicuticular channels. This material (which is often called 'outer epicuticle') has the same staining and resistance properties as the true outer epicuticle on which it rests. In the abdomen of Calliphora adult the waterproofing wax-sclerotin mixture forms a thin layer over the entire cuticle including the surface of the microtrichia. There is also a thin detachable layer of free wax on the surface.

Enzymatic and hemolytic properties of brown recluse spider (Loxosceles reclusa) toxin and extracts of venom apparatus, cephalothorax and abdomen

Loxosceles reclusa venom apparatus extract, toxin, cephalothorax and abdomen extracts were tested for six activities. Protease, lipase, nonspecific hydrolase and direct hemolytic activities were found primarily in abdomen extracts while sphingomyelinase activity appeared predominantly in the toxin. Appreciable complement-mediated hemolysis was not observed.

Percutaneous transport in relation to stratum corneum structure and lipid composition

Despite the acknowledged importance of the stratum corneum in limiting water loss and in controlling skin permeability, the basis for these functions remains unknown. To pinpoint those factor(s) of importance for cutaneous barrier function, we correlated the thickness, number of cell layers, and lipid composition of leg vs. abdominal stratum corneum samples with penetration of 3H-water and 14C-salicylic acid across the same tissue sample. Viable upper epidermal sheets were obtained by incubating fresh autopsy or amputation full-thickness skin with staphylococcal exfoliatin. Each sheet was divided into 3 portions. The first piece was mounted in a diffusion cell for penetration studies. The second stratum corneum sample was frozen sectioned, stained with the fluorochrome, ANS, and measured with a micrometer eyepiece. The 3rd piece was pooled with other leg (n = 6) and abdomen (n = 15) specimens for determination of lipid weight percent. In all cases, leg stratum corneum was congruent to 2 times more permeable than abdominal stratum corneum to water and slightly more permeable to salicylic acid, as well. Penetration of both substances correlated inversely with lipid weight % of leg (mean = 3.0%) vs. abdomen (mean = 6.8%), but neither the penetration of water nor of salicylic acid was influenced by the number of cell layers or the thickness of the stratum corneum. We conclude that: differences in the thickness and the number of cell layers in the stratum corneum are insufficient to account for differences in percutaneous transport across leg and abdomen, and that total lipid concentration may be the critical factor governing skin permeability.

The disposition of aromatic hydrocarbons in adult spot shrimp (Pandalus platyceros) and the formation of metabolites of naphthalene in adult and larval spot shrimp

1. Adult spot shrimp (Pandalus platyceros) exposed to 110 p.p.b. (microgram/ml) of the water-soluble fraction of Prudhoe Bay crude oil for one week accumulated a variety of low-molecular weight aromatic hydrocarbons (primarily C1-C5 substituted derivatives) in thoracic and abdominal tissues. 2. Adult and larval spot shrimp were exposed to 3H- and 14C- labelled naphthalene (a component of the water-soluble fraction) in seawater to delineate the types of metabolites formed. Both adults and larvae converted naphthalene to conjugated and non-conjugated structures such as the glucuronide, sulphate, dihydrodiol and phenolic derivatives. The presence of a quinone was also indicated.

A glutaraldehyde/potassium dichromate tracing method for the localization and preservation of abdominal extra-adrenal chromaffin tissues

The present work introduces a method for the localization in situ of the abdominal paraganglia. After treating retroperitoneal tissue blocks with a near-neutral glutaraldehyde/potassium dichromate solution following routine glutaraldehyde perfusion, intra- and extraadrenal chromaffin tissues develop a pronounced brown color from the interaction of glutaraldehyde/potassium dichromate with amines. In this manner, visualization of the abdominal extra-adrenal chromaffin organs is enhanced at the same time that cellular ultrastructure is preserved. Subsequent examination of the dichromate-reacted tissues with the electron microscope confirms that they represent the amine-rich paraganglia. This method offers an effective alternative to extensive sampling of plastic-embedded blocks for localizing peripheral chromaffin tissue and has been used to define the exact distribution of abdominal paraganglia in the rabbit.

Distribution of gold Au 198 after intraperitoneal injection in animals

The distribution of gold Au 198 after intraperitoneal administration in dogs and rats was determined by scans and tissue radioassays obtained 24 hours after injection. Relative activity and percent of injected radioisotope contained in different organs were calculated. The radioisotope was found to be heavily concentrated in mediastinal lymph nodes and liver, with liver uptake averaging 36.5% of the injected isotope 24 hours after injection. The use of therapeutic intracavitary radiocolloids should be reevaluated in light of possible excessive irradiation of the liver.