Lipid Basis Research Articles

Impairment of schedule-controlled behavior by pre- and postnatal exposure to hexachlorobenzene in rats.

Hexachlorobenzene (HCB) is still frequently found at elevated levels in human adipose tissue and breast milk. As intoxication with HCB causes neurological disturbance in human beings, the purpose of the present study was to examine neurobehavioral functions in rats after pre- and postnatal exposure. Female rats were fed diets with 0, 4, 8, or 16 mg HCB/kg diet. Exposure started 90 days prior to mating and was continued throughout mating, gestation, and lactation. Thereafter, the offspring were given the same diets as their respective mothers. HCB levels were determined in the brain, the liver, and in the adipose tissue from virgin rats, dams, and the offspring. Concentrations on a lipid basis were found to decline in the order adipose > liver > brain. The exposure levels chosen did not cause gross toxic effects in dams or offspring. There were dose-related increases in liver-to-body-weight ratios in exposed dams, but not in unmated females treated alike. Behavioral testing was conducted in the offspring. Examination of open-field activity on PND 21, and of active avoidance learning on PND 90 failed to reveal significant differences between groups. Training of operant behavior started at the age of 150 days in the offspring from the control, the 8-mg group, and the 16-mg group. Animals were trained on a fixed interval schedule of 1 min (FI-1). On this schedule, responses were reinforced by a food pellet every time 1 min had elapsed after the preceding reinforcement. There were dose-dependent reductions in the post-reinforcement pause, e.g. the time between each reinforcement and the first reaction emitted after it. In addition, the index of curvature, which describes the efficiency of performance on the FI-1 schedule, was decreased in a dose-dependent fashion.

Soy Protein Isolate Solubility and Surface Hydrophobicity as affected by Antioxidants

ABSTRACTAddition of tert‐butylhydroquinone or a mixture of butylated hydroxyanisole and tert‐butylhydroquinone (200 ppm on a lipid basis) during SPI processing gave increased protein solibility over that of the control (55%. 56% and 34%. respectively). These increased solubilities correspond to 32% and 18% decrease in oxidation of free sulfhydryls and 20% and 12% reduction in protein oxidation, as determined by protein carbonyl content. Increased protein solubilities, due to added antioxidants, were accompanied by higher total protein surface hydrophobicity, as determined by the sodium dodecyl sulfate (SDS) binding method, and soluble protein hydrophobicity, as determined by the fluorescence probe 8‐anilino‐1‐naphthalene sulfonate (ANS).

Effect of muscle type and food deprivation for 24 hours on the composition of the lipid fraction in muscles of Large White pigs

The present study was designed to examine the lipid composition of a predominantly glycolytic ( M. longissimus lumborum, LL) and a predominantly oxidative ( M. semispinalis capitis, SC) muscle sampled at slaughter from Large White pigs fed or deprived of food for 24 h. The intramuscular lipid content was almost four-fold higher in the red SC than in the white LL. When expressed on a muscle tissue basis, the results indicated that the LL had significantly lower amount of tri-, di- and monoglycerides, free fatty acids, cholesterol and phospholipids than the SC. In both muscles, phosphatidylcholine represented the major constituent of the phospholipid fraction. The difference in phospholipid content between the LL and the SC was significant only for cardiolipin, phosphatidylethanolamine and phosphatidylinositol. When expressed on total lipid basis, the results showed that the SC contained significantly lower amount of phospholipids and higher amount of triglycerides than the LL, thus suggesting that the influence of muscle type on the content of intramuscular lipid was primarily due to a difference in the amount of triglycerides. Food deprivation for 24 h resulted in a significantly higher content of free fatty acids, as expressed on a muscle tissue basis, in both muscles. Relative to total lipid, food deprivation resulted in increased levels of free fatty acids and monoglycerides only in the LL. These results suggest that food deprivation for 24 h induced lipolysis in muscle, as evidenced by a modification in the relative composition of the neutral lipid fraction, but that this effect was muscle-dependent.

Accumulation of hexachlorobenzene in humans: a long standing risk

1. Hexachlorobenzene (HCB) internal dose in the general population of Barcelona (Spain) was estimated after new indications of the carcinogenicity of this chemical in humans were recently reported. Hospital blood bank facilities and randomly selected volunteers were used for HCB analyses in serum (n = 100) and cerumen (n = 25). Other main organochlorine residues often found in human tissues and blood (pp DDE, beta-HCH,) were also determined. 2. HCB serum levels currently found (Range 0.7-19.7 ng Ml-1; X +/- s.d.: 4.13 +/- 3.61; GM: 3.05) were compared to those found in a similar survey made in 1986 on the same population. The serum HCB levels showed a significant decrease (P < 0.001) when compared to the former results and correlated with age (P < 0.001) suggesting a progressive preponderance of a stable blood-adipose equilibrium with fewer variations due to recent and variable intake of the chemical. 3. Cerumen analyses revealed detectable concentrations of HCB in all samples (Range: 160-4790 ng g-1 in extractable lipid basis) and confirmed the suitability of this matrix to assess the body burden of residues accumulated in adipose and lipid-rich tissues. The set of results shows that, although HCB exposure has been reduced, the overall population under study still accumulates significant amounts of this possible carcinogen.

Elevated dioxin blood levels in Russian chemical workers and their children following maternal exposure

Elevated dioxin levels in children of female workers with elevated dioxin body burden following workplace exposure has not been previously reported. We previously reported elevation of polychlorinated dibenzo-p-dioxins, particularly 2,3,7,8-TCDD, in Russian male and female chemical production workers' blood. Exposure is thought to have occurred in the early 1960s and blood was drawn in 1991. (1) Among those with elevated dioxin levels were women with grown children. Since dioxins can be transferred transplacentally (2) and by nursing, (3,4) it was decided to see if a relationship existed between blood dioxin levels in mothers and their children. Individual samples were obtained from factory office workers, production workers and their now adult offspring. A pooled blood sample (n=100) from adult Ufa residents was obtained for comparison. Samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (CoPCBs). Office workers, production workers and workers' children 2,3,7,8-TCDD (TCDD) blood levels ranged from 11 to 273 parts per trillion (ppt) on a lipid basis, while the pooled blood sample (n=100) from adult Ufa residents had a TCDD level of 12 ppt. Elevated TCDD was detected in all adult children of female production workers tested while two adult children of a male production worker had dioxin levels similar to the general population of Ufa. All children of workers had been nursed by their mothers for the first year of life and none have worked at a chemical plant. The data suggest that relatively large amounts of TCDD were transferred from mother to child approximately 18 to 28 years prior to blood collection. A sample of 2,4,-D amine salt produced at this factory was also analyzed to determine if its dioxin congeners might be contributing to dioxin contamination. 2,3,7,8-TCDD was not detected in the 2,4-D (detection limit of 0.02 ppb), although other dioxins were present, including some with 2,3,7,8- chlorine substitution.

Traditional lipoprotein profile: clinical utility, performance requirements, and standardization

The lipid and lipoprotein parameters which are predominantly measured and effectively comprise the traditional lipoprotein profile include total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and triglyceride. Total cholesterol is accepted as the initial entry point in a case finding approach such as that recommended by the National Cholesterol Education Program (NCEP). HDL cholesterol, known to be a strong inverse predicator of risk, is an additional measurement to total cholesterol to improve risk assessments. The evidence for triglyceride association remains mixed: although strong associations are found in some studies, the evidence as an independent risk factor is still incomplete. Triglyceride is therefore measured primarily for LDL estimation. Final classification and potential intervention is ultimately based on the measurement of LDL cholesterol. Reliability in the measurement of total cholesterol, HDL, LDL, and triglyceride is especially important if the uniform decision points established by the NCEP are to be properly implemented. Attention must be placed on controlling preanalytical sources of variation, which can account for as much as 60% of the total measurement variability. The major analytical source of error comes from matrix effects, which results in problems of proper analytical calibration. Instrument system calibration should be verified by a comparison with an accuracy base using fresh patient specimens. CDC has established a network of reference method laboratories to provide access to these lipid and lipoprotein accuracy bases.

Pesticide Bioaccumulation in Cattle

A simple partition model was developed to evaluate the bioaccumulation of chlorinated hydrocarbon pesticides (dieldrin and heptachlor) in the soil-pasture-grazing animal system. Biomagnification factors (BF L) calculated on a lipid basis ranged from 0.115 to 0.175, but could not be directly compared with other values from the literature because of different methods of calculation. The partition model predicted values of somewhat less than unity, indicating that it does not fully account for pesticide pathways and mechanisms. However, the lack of variation of these values from two compounds indicates a lack of dependence on the octanol/water coefficient which is in accord with the model. The results suggest partitioning between food in the stomach and body tissues is a major bioaccumulation process but other major processes are also involved.

Organochlorine Pesticides in Spanish Sterilized Milk and Associated Health Risks

Organochlorine pesticides (α-HCH, β-HCH, lindane, γ-HCH, aldrin, dieldrin, heptachlor, heptachlor epoxide, clordane, pp'-DDE, op'-DDD, pp'-DDD, op'-DDT, pp'-DDT endrin and methoxychlor) were investigated in Spanish sterilized milks. Ninety percent of the milk samples were found to be contaminated. Thirty-two percent of the samples were contaminated by clordane and showed levels which exceeded the maximum residue limit permitted in the Directive 86/386/EC for organochlorines in milk as calculated on a lipid basis. Aldrin was only found in one sample, while 89.9% of the samples were contaminated by one or more HCH isomers. Mean heptachlor epoxide contamination (0.026 ppm) was approximately 10 times higher than contamination by heptachlor, There is no health risk involved in the consumption of using sterilized milk in Spain.

The value of figs to a hind-gut fermenting frugivore: a nutritional analysis

The fleshy wall of figs is an important food item for a wide range of frugivore animals. However, the nutritional significance of figs as a genus is poorly understood and somewhat puzzling, since there is considerable variation among species in chemical content. This study examined nutritional features of nine species of Ugandan figs, from Kibale Forest, eaten by chimpanzees ( Pan troglodytes) and many other frugivores. Fig samples were chemically analyzed for their percentages of lipid, crude protein (CP), available protein, water-soluble carbohydrates (WSC), pectin, total cell wall, hemicellulose, cellulose, lignin, cutin, tannins, dry matter and total ash. Complex carbohydrates ( cxCHO) were calculated by difference. The pulp or flesh of the figs was analyzed separately from the seed fraction. None of the assayed nutrients alone explain why figs are eaten by so many of the frugivores in Kibale Forest. Furthermore, standard calculations suggested that figs have rather low values of metabolizable energy (ME). However ME may be misunderstood when calculated by the orthodox method, because it does not aknowledge nutritional components available to frugivores capable of fore- or hind-gut fermentation. As a result of including pectin, hemicellulose and cellulose as potential energy sources through fermentation, we suggest that total ME for a chimpanzee is some 50% higher (2.78 kcal g −1 compared to 1.91 kcal g −1) than estimated purely on the basis of cxCHO, WSC, CP and lipid. When calculated in this way, the digestibility/fermentability of soluble and insoluble fiber components may explain the attractiveness of figs to many frugivores.

Levels of selected individual polychlorinated biphenyls in different tissues of harbour seals ( phoca vitulina) from the Southern coast of Norway

Concentrations of individual polychlorinated biphenyls (PCBs) were determined in blubber, liver, kidney and brain tissues of 10 male harbour seals ( Phoca vitulina) of different ages. The animals were found dead or dying on the southern coast of Norway in 1988 during the morbilli virus epizootic. Twenty-three PCB congeners were investigated in all tissues by capillary gas chromatography with electron capture detection and comparison with standards of the respective congeners (IUPAC numbers 28, 52, 74, 99, 101, 105, 110, 114, 118, 128, 138, 141, 149, 153, 156, 157, 170, 180, 183, 187, 194, 206 and 209). In addition, three toxic coplanar congeners (IUPAC numbers 77, 126 and 169) were investigated in the blubber samples. Total PCB (sum of the determined congeners) in kidney (12–60 nmol g −1), liver (12–90 nmol g −1) and blubber (10–79 nmol g −1) were similar on extractable lipid basis, while total PCB in brain lipid was about 1/10 (1·6–12 nmol g −1). The absolute concentrations of the individual congeners in brain lipid correlated poorly with the respective concentrations in each of the other tissues, while the individual congener concentrations in the lipid fractions of kidney, liver and blubber tended to correlate with each other. The relative concentrations of the sum of the most persistent congeners (PCB-99, −128, −138, −153, −170, −180, −187 and −194) correlated in all tissues, and an increase of the relative concentrations of these congeners, most distinct in blubber, with higher carcass weight, was shown. Also, total PCB in blubber correlated with carcass weight. When comparing the relative concentration patterns of individual congeners (per cent of total) in the four tissues, six congeners differed significantly between tissues, and the relative brain concentrations showed most deviation from the other tissues. The concentration of the coplanar PCBs was 1 : 1000–1 : 1000 of the total PCB concentration. The results demonstrate a lower accumulation together with a different concentration pattern in the brain as compared to other tissues.

Distribution of PCB congeners in seven lake systems: Interactions between sediment and food-web transport

A study was conducted to examine the role of two processes, partitioning of PCBs between sediment and biota and food-web transport, in determining the concentration of PCB congeners in the biota of seven lakes. Biota PCB concentration (lipid)-to-sediment PCB concentration (organic carbon), or BSF, ratios were calculated as markers of the partitioning of PCBs between biota and sediment, and biota PCB concentration (lipid)-to-zooplankton PCB concentration (lipid), or BAF, ratios were calculated as markers of the transport of PCBs through food webs. The lakes ranged from a shallow, well-mixed lake with a historic input of Aroclor technical mixtures to deeper, oligotrophic systems in which atmospheric deposition was the only known source. BSF ratios ranged from approximately one in cyprinids and zooplankton in all lakes to 30 in yellow perch in one lake. A significant correlation between lake maximum depth and the combined BSF ratios for all biota indicated that PCBs were generally more available for accumulation in the shallower lakes, regardless of the PCB source. Principal component analysis (PCA) showed that the biota in the shallower lakes had higher ratios of higher chlorinated congeners, suggesting that predictions of equal concentrations of hydrophobic contaminants on a lipid basis in sediment and lower trophic levels may significantly underestimate the accumulation of very hydrophobic compounds in the organisms of some lake systems. BAF ratios ranged from approximately one in the lower trophic levels to approximately 10 in lake trout. A significant relationship between the BAF ratio and lake maximum depth for combined data for all biota, and particularly for smallmouth bass (Micropterus dolomieui Lacé-pède), probably indicated the increasing role of food-web transport of PCBs in deeper lakes. PC analysis of BAF ratios for individual congeners characterized lake trout (Salvelinus namaycush Wal-baum) and yellow perch (Perca flavescens) on the basis of higher ratios for the majority of congeners but also split the two species on the basis of higher ratios of lower chlorinated congeners in perch and highly chlorinated congeners in lake trout. The separation of the two species collected from the same lakes was attributed to their position in the food web.

Total Organochlorine Content of Fish from the Great Lakes

Residues of polychlorinated biphenyls (PCBs) and organochlorine pesticides were determined in several species of commercial fish from the Great Lakes and compared to the total organic chlorine determined by neutron activation analysis. The mean organochlorine contents ranged from 44 to 138 ppm (lipid basis) and were 5 to 72 times higher than the contents of PCBs and organochlorine pesticides. Marine fish also contained a large proportion of unidentified organic chlorine. The unknown material in the Great Lakes fish was found to chromatograph with the high molecular weight lipid fraction by gel permeation chromatography.

Elevated dioxin levels in the blood of male and female russian workers with and without chloracne 25 years after phenoxyherbicide exposure: The UFA “Khimprom” incident

The results of dioxin blood analyses are presented for three men and four women who were among 231 workers exposed to dioxins at a chemical factory in Ufa, Russia, approximately 25 years prior to blood collection and analysis in 1991 and 1992, respectively. Five of the seven (three male workers and two female workers), were diagnosed with chloracne after manufacturing 2,4,5-trichlorophenoxy-acetic acid contaminated with 2,3,7,8-TCDD (TCDD) between 1965 and 1967 at the Agrochemical complex in that city. This is, to the best of our knowledge, the first reported incident of chloracne in females with elevated dioxin blood levels from occupational exposure. The workers were found to have elevated levels of 2,3,7,8-TCDD ranging from 36 to 291 parts per trillion (ppt) on a lipid basis, with a mean of 185 ppt, where a general Russian population pooled sample (N=68) averaged 4.4 ppt. Unlike previous reports of human tissue dioxin levels following exposure to 2,4,5-T, several other congeners were elevated in some workers, including 1,2,3,7,8-PnCDD, and to a lesser extent, 1,2,3,4,7,8/1,2,3,6,7,8-HxCDD, OCDD, 2,3,4,7,8-PnCDF, 1,2,3,4,7,8/1,2,3,6,7,8-HxCDF and 1,2,3,4,6,7,8-HpCDF. We compare the dioxin (PCDD) and dibenzofuran (PCDF) levels and dioxin toxic equivalents (TEQ) of these workers with those of non-exposed Russians and estimate that the workers' total dioxin toxic equivalent levels in 1967 ranged from 226 to 1,707 ppt assuming a 10 year half-life, and 1,173 to 9,366 ppt assuming a 5 year half-life of elimination for 2,3,7,8-TCDD. We estimate the total body burden of 2,3,7,8-TCDD for the workers to have been between 22 and 172 μg using a 5 year half-life of elimination and 4 to 30 μg if the half life was 10 years. We also measured the coplanar polychlorinated biphenyls (CoPCBs) in these workers and found them to range from 81 to 329 ppt lipid for those detected. We believe this to be the first measurement of coplanar PCBs in blood of Eastern Europeans.

Characterization of the family pasteurellaceae on the basis of cellular lipids and carbohydrates

Selected strains representing established and newly described taxa in the family Pasteurellaceae were investigated for their cellular lipid and carbohydrate composition to clarify the taxonomic significance of such features. Methylated cellular fatty acids and acetylated derivatives of the cellular carbohydrates were determined by capillary gas chromatography using a flame ionization detector. In part the carbohydrates were identified by mass spectrometry. Phospholipids were determined by thin layer chromatography, the lipoquinones by high pressure liquid chromatography. The cellular fatty acid patterns proved to be uniform with minor variations, but the separation from the Neisseriaceae and from Moraxella was possible. Also the distribution of the phospholipids was uniform within the family. The lipoquinone contents were useful for the discrimination of groups within the family not necessarily reflecting the degree of genomic relatedness. The analysis of the cellular carbohydrates resulted in a common sugar pattern with all members of the family and characteristic carbohydrate profiles discriminating groups, often to the species level. All of the cytochemical features considered were useful for the characterization of the family Pasteurellaceae.

Bioconcentration factors and kinetics of chlorobenzenes in a juvenile crab (Portunus pelagicus (L))

The uptake- and depuration-rate constants (k1 and k2 respectively), according to first-order kinetics, were measured for a series of chlorobenzenes with juvenile crabs, Portunus pelagicus. These constants were found to be related to the lipophilicity of the chlorobenzenes as expressed by the octanol-water coefficient (log Kow), giving relationships similar to those observed with fish. However, the actual magnitude of k1 and k2 on a lipid basis ranged from 720 to 5880 h-1 and from 0.492 to 0.0102 h-1 respectively, which is about ten times faster than those for fish. The bioconcentration factor (KB in wet weight units) obtained from these rate constants was related to Kow, by the following expression. log KB=-2.88+1.09 log Kow. The empirical constants in this equation are similar to those observed with other aquatic organisms except that the value of -2.88 is lower than that reported with the other organisms. This is probably due to the relatively low lipid content of the crabs. It is suggested that the bioconcentration of essentially nonbiodegradable lipophilic compounds occurs as a result of partitioning between biota lipid and water. Other physicochemical properties (molar volume and aqueous solubility) and two molecular descriptors (zero- and first-order Randik indices) exhibited good correlations with the bioconcentration characteristics described above.

Partitioning of dioxin and dibenzofuran congeners between plasma and cell fractions of blood from 10 adult male patients

We previously characterized levels of dioxin and dibenzofuran congeners in adipose tissue and plasma fraction of blood collected from 20 adult males, using paired speciments. It has been found that the 2,3,7,8-TCDD level reported on a lipid basis was similar, although not identical, in plasma lipid and in adipose tissue lipid from the same patients, however, higher levels of the more chlorinated dioxins and dibenzofurans existed in plasma lipid as compared to adipose tissue lipid. This study reports measurements from ten individuals' blood cell fraction and compares this to the plasms fraction and to adipose tissue lipid. In all cases where readily detectable amounts of PCDD/Fs were found, a minimum of 85% was in the plasma fraction and less than 15% in the cellular component. Congeners varied in percentage for each component.

Levels of dioxins, dibenzofurans and selected other chlorinated organic compounds in food from Russia

Food is considered to be the main source of dioxins (PCDDs) and dibenzofurans (PCDFs) for human intake, but there are relatively few publications reporting the levels of dioxins and furans in food samples. (1–4) Food samples from western to eastern Russia were collected during three recent trips by one of us (AS), and tested for dioxins and dibenzofurans to provide some indication of environmental contamination. The results show that in specific food samples there are more dioxins present than dibenzofurans, but in fish samples the opposite is true. We compare the levels found in Russian food with levels found in samples from other countries, on both wet weight and lipid basis. These Russian samples show ranges similar to but slightly lower than those seen in other industrial countries.

Bioconcentration of octachlorodibenzo- p-dioxin (OCDD) in fish

The most convincing argument against the hypothesis that persistent superlipophilic chemicals with log K OW >6, such as OCDD are bioconcentrated - if at all - to a low extent is that in all these bioconcentration experiments, except of 2,3,7,8-TCDD, exposure concentrations have been applied which exceeded water solubility by several orders of magnitude. In this paper, a indirect method for the estimation of bioconcentration factor (BCF) of OCDD is presented: The BCF value on a lipid basis (BCF L) of 8.5∗10 7 in fish was obtained from an extrapolation fo a linear log/log relationship for kinetically measured BCF L data in fish and the OCDD concentration in the water up to water solubility of this chemical.

Calorimetry of tetraether lipids from Thermoplasma acidophilum: Incorporation of alamethicin, melittin, valinomycin, and nonactin

The development and application of model membrane systems on the basis of tetraether lipids from Thermoplasma acidophilum has been proposed. In this respect incorporation of membrane proteins and ionophores is indispensable and is demonstrated in the case of alamethicin, melittin, nonactin, and valinomycin by calorimetry. Dipalmitoylphosphatidylcholine (DPPC) and dihexadecylmaltosylglycerol (DHMG) were chosen for comparison. Melittin and alamethicin prove to broaden the lipid phase transition and to reduce the melting temperature T m and enthalpy change (Δ H) of the main phospholipid from T. acidophilum (MPL) and DPPC. The decrease in T m, however, is more pronounced in DPPC than in MPL. Valinomycin shows only a marginal effect on the temperature and width of the transition; Δ H is reduced in MPL and remains constant in DPPC and DHMG. With nonactin the phase transition of DPPC is quenched, and Δ H and the half-height width are increased. DHMG is affected to a lesser extent and MPL only marginally. The four ionophores exhibit different modulation of the phase transition behavior of the various lipids as expected from their varying molecular structures. Thus, the integral membrane protein alamethicin, the peripheral protein melittin, valinomycin, and nonactin interact primarily with lipid head groups and are readily incorporated into the tetraether lipid structures.

Project TOCOEN. The fate of selected organic pollutants in the environment

Samples of subcutaneous abdominal adipose tissues were analysed to obtain preliminary information on the level of general population exposure to polychlorinated biphenyls (PCBs). Three different regions—cities and their neighbouring districts—were chosen for comparison of the levels of contamination in Slovakia: Bratislava, Trencin and Martin. Samples were obtained by autopsy. Highest concentrations were found in patients from the relatively densely population region with heavy chemical industry (Bratislava; males 0.7–10.4 mg.kg‐1 on lipid basis, females 0.6–7.7). Lower concentrations were found in the smaller towns and zones with different type of industry (engineering): Trencin— males 2.1–5.5, females 0.4–6.1 and Martin—males 0.4–4.7, females 0.4–4.8. The daily PCB intake in the general population of Slovakia was calculated from the obtained and published data1,2. This intake was found to be between 0.2 and 4.0 μg.kg‐1.day‐1.