Properties of the Plasma Very Low and Low Density Lipoproteins in Tangier Disease

The absence of normal high density lipoproteins (HDL) in Tangier disease is well established, but the properties of very low density lipoproteins (VLDL) and low density lipoproteins (LDL) in this disorder have not been well defined. The profiles obtained by analytic ultracentrifugation and the chemical composition, morphology, and electrophoretic mobility of Tangier and normal VLDL and LDL were compared. Apolipoproteins were fractionated by gel chromatography and characterized by amino acid analysis, polyacrylamide-gel electrophoresis, and immunochemical reactivity.Concentrations of low density lipoproteins of S(f) (o) 0-12 were reduced in three of six Tangier plasmas studied by analytic ultracentrifugation. Accumulation of intermediate density lipoproteins (S(f) (o) 12-20) was not observed. Two subjects with hypertriglyceridemia had normal VLDL (S(f) (o) 20-400) levels, suggesting that abnormalities of chylomicron metabolism probably account for the hypertriglyceridemia frequently observed in this disorder.Tangier VLDL migrate more slowly than normal VLDL on paper electrophoresis, yet their morphology, gross chemical composition, and qualitative apolipoprotein content are similar. Quantitative abnormalities in C-apolipoproteins, however, were observed in Tangier VLDL. When patients were consuming unrestricted diets, C apoproteins accounted for 19-49% of the protein in lipoproteins of d < 1.006 g/ml. Ingestion of low-fat, high-carbohydrate diets reduced the VLDL-C-apoprotein content in all Tangier patients (mean = 17% of VLDL protein vs. 43% in controls). These findings suggested that a major proportion of the C apoproteins in Tangier plasma is associated with chylomicrons or their remnants, perhaps because the C-apoprotein reservoir normally provided by HDL is absent. This secondary mechanism for C-apoprotein conservation is lost when dietary fat is withdrawn.LDL-2 (1.035 < d < 1.063) from Tangier and control plasma had identical electrophoretic mobilities. Tangier LDL-2 had slightly smaller median diameters (210-225 A vs. 230-240 A in controls) and a quite different composition than normal LDL-2. Triglyceride accounted for a mean of 29% of Tangier LDL-2 mass (control = 6%) and the cholesteryl ester content was reduced by about 50%. Thus, HDL may be required for the generation of chemically normal LDL. Alternatively, the fundamental defect in Tangier disease may involve all lipoprotein classes.     

Macrophages and Oxidized Low Density Lipoproteins in the Pathogenesis of Atherosclerosis

Oxidized low density lipoprotein (LDL) may play an important role in the pathogenesis of atherosclerosis. Recent evidence strongly suggests that oxidized LDL is present in atherosclerotic lesions in vivo: 1) LDL isolated from human and rabbit lesions (but not from normal intima) resembles oxidized LDL in its physical, chemical and immunological properties; 2) Oxidized LDL and/or oxidation specific lipid-protein adducts can be demonstrated in human and rabbit lesions by immunocytochemical techniques; 3) Human and rabbit serum contains autoantibodies against oxidized LDL and oxidation specific lipid-protein adducts; 4) atherosclerotic lesions contain IgG that recognizes oxidized LDL and 5) antioxidant therapy slows the development of atherosclerotic lesions in rabbits. Atherosclerosis in human and rabbit arteries may be linked to macrophage-induced oxidative modification of LDL mediated by 15-lipoxygenase which leads to an enhanced uptake of LDL in macrophages by way of the scavenger receptor(s). The identification of LDL oxidation as one of the key events in the early pathogenesis of atherosclerosis offers an interesting possibility to reduce atherosclerosis by antioxi-dants, enzyme inhibitors and other compounds that protect LDL against oxidative damage and/or reduce the subsequent harmful effects of oxidized LDL on various cellular functions.     

Metabolism of Very Low Density Lipoproteins in Hyperlipidaemia: Studies of Apolipoprotein B Kinetics in Man

The metabolism of very low density lipoprotein-B (VLDL-B) peptide was studied in nineteen subjects with endogenous hypertrigylceridaemia (Types V, IV and lib), three patients with heterozygous familial hyperbetalipoproteinaemia (Type Ila) and eight healthy subjects, by reinjecting autologous radioiodinated VLDL. The kinetics of VLDL-B peptide were followed. The mean turnover rate of VLDL-B peptide was significantly higher in the hypertriglyceridaemic group than in the control group but a considerable overlap in turnover rate was found between these groups. The patients with heterozygous familial hyperbetalipoproteinaemia had a normal turnover rate of VLDL-B peptide. A significant positive correlation was found between the turnover rate of VLDL-B peptide and VLDL-triglyceride concentration in the whole series. It is concluded that the underlying defect in endogenous hypertriglyceridaemia is heterogeneous. Overproduction of VLDL is a major determining factor in seme patients whereas a reduced clearance is the determining factor in others.     

Lipolysis Produces Changes in the Immunoreactivity and Cell Reactivity of Very Low Density Lipoproteins

Smaller very low density lipoprotein (VLDL) remnants interact more readily with tissues than do larger "intact" VLDL. This may be related to changes in the availability of VLDL apoproteins on the surface of the lipoproteins. To test this hypothesis VLDL were incubated at 37 degrees C with bovine milk lipase (LPL), and the abilities of LPL-treated VLDL preparations to compete with (125)I-low density lipoproteins (LDL) for interaction with cultured normal human fibroblasts were measured. At the same time, the immunologic activities of these preparations were also tested by double antibody radioimmunoassay. Triglyceride (TG) contents of VLDL fell by 30-90% during incubation with LPL and, on zonal ultracentrifugation, VLDL of faster Svedberg unit of flotation (S(f1.063)) rates (>150) were gradually converted to smaller VLDL with lower S(f) rates (21-60). LPL-treated VLDL competed two to five times more effectively with (125)I-LDL for binding to cellular receptors than did control VLDL. Control VLDL incubated with heat-inactivated LPL at 37 degrees C, or with active LPL at 4 degrees C had unaltered cell reactivities and TG contents compared with VLDL incubated without any enzyme. The direct uptake and degradation of LPL-treated VLDL was also assessed by using VLDL (125)I-labeled in apoprotein (Apo)B. LPL-treated VLDL-(125)I-ApoB were taken up and degraded by fibroblast at greater rates than were control VLDL-(125)I-ApoB. Thus, hydrolysis of VLDL lipids was accompanied by an increased ability of VLDL to interact with fibroblasts. The immunoreactivity of ApoB in the same VLDL preparations, expressed as the "apparent ApoB contents" of LPL-treated VLDL, increased by 10-50% (P < 0.02) in those assays that contained anti-LDL antisera, but the ApoB of control VLDL remained constant. However, assays that contained antisera directed against ApoB isolated from VLDL did not distinguish between LPL-treated and control VLDL. Thus, VLDL lipid hydrolysis was accompanied by changes in the immunoreactivity of VLDL-ApoB, which probably reflect changes in the disposition of ApoB on the surface of VLDL. The altered disposition of ApoB on VLDL "remnants" may be related to their enhanced interaction with cells.     

Further Aspects on the Characterization of High and Very Low Density Lipoproteins in Patients with Liver Disease

Abstract Various liver disorders are often associated with decreased concentrations of serum α- and pre- β-lipoproteins. The decreased concentrations of high density lipoproteins (HDL) is primarily due to an impaired lipid binding capacity of apolipoprotein A (apo A), the major protein moiety of HDL. This results in an abnormally high protein/lipid ratio and in severe cases in a lack of neutral lipids in this density class. In contrast to normal α-lipoproteins this fraction does not stain for lipids but shows two distinct and nonidentical precipitin bands on immunoelectrophoresis and immunodiffusion. The isolated very low density lipoproteins (VLDL) from patients with liver disorders revealed a regular particle size and a protein/lipid ratio close to normal but developed β-mobility on electrophoresis. Analysis of the protein moieties of this fraction indicated a lack of apolipoprotein A. It is suggested that disturbed liver function leads to the synthesis of an altered apo A resulting (a) in α-lipoproteins with dissociated apo A peptides and (b) in very low density lipoproteins devoid of apo A. Both findings may be explained by the impaired capacity of this apolipoprotein A to bind neutral lipids.     

Mast Cell Granule-Mediated Uptake of Low Density Lipoproteins by Macrophages: A Novel Carrier Mechanism Leading to the Formation of Foam Cells

Mast cells are present in the arterial intima, the site of atherogenesis. To gain insight into the possible role of mast cells in the formation of the cholesterol-loaded macrophage foam cells typical of both early and late atherosclerotic lesions, a model system was developed in which isolated rat serosal mast cells were incubated with mouse peritoneal macrophages in medium to which low-density lipoproteins (LDL) had been added. Stimulation of the mast cells was found to induce a 50-fold enhancement of LDL uptake by the macrophages, which concomitantly accumulated LDL-derived cholesterol. This process, called the “granule-mediated uptake of LDL”, involves the following steps: (i) exocytosis of the cytoplasmic granules of the mast cells, (ii) escape of soluble granule components, such as histamine and a fraction of the granule heparin proteoglycans into the medium, leaving granule remnants consisting of neutral proteases embedded in a heparin proteoglycan matrix, (iii) binding of LDL to binding sites on the glycosaminoglycan side chains of the heparin proteoglycan component of the granule remnants, (iv) proteolytic degradation of the bound LDL by the neutral proteases of the granule remnants, (v) fusion of degraded LDL particles on the surfaces of the granule remnants, and (vi) phagocytosis of the LDL-laden granule remnants by the macrophages. Simultaneously, the soluble heparin proteoglycans, to which no proteolytic enzymes are bound, interact with LDL with formation of insoluble complexes which are also phagocytosed by the macrophages. Finally, cholesterol derived from the granule remnant-bound LDL and the LDL-heparin proteoglycan complexes becomes esterified by the macrophages, with formation of macrophage foam cells. Experiments in vivo showed that granule remnants may also carry LDL into macrophages in the peritoneal cavity of the rat, where mast cells and macrophages coexist. The results suggest that mast cells play an active role in the intracellular cholesteryl ester deposition characteristic of human atherosclerotic lesions.     

Control of 3-Hydroxy-3-Methylglutaryl-CoA Reductase Activity in Cultured Human Fibroblasts by Very Low Density Lipoproteins of Subjects with Hypertriglyceridemia

Very low density lipoproteins (VLDL) and low density lipoproteins (LDL) from human normolipemic plasma, and the VLDL, the intermediate density lipoprotein (IDL), and LDL from patients with Type III hyperlipoproteinemic plasma were tested for their abilities to suppress the activity of 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase in cultured human fibroblasts from normal subjects and a Type III patient. Regulation of cholesterol synthesis in the fibroblasts of a patient with Type III hyperlipoproteinemia appears to be normal. VLDL from normal subjects, isolated by angle head ultracentrifugation (d < 1.006) or by gel filtration on BioGel A-5m, were about 5 times less effective than LDL in suppressing HMG-CoA reductase activity, based on protein content, in agreement with previous reports with normal fibroblasts. Zonal centrifugation of normal VLDL isolated by both methods showed that the VLDL contained IDL. Normal VLDL from the angle head rotor, refractionated by the zonal method, had little, if any, ability to suppress the HMG-CoA reductase activity in either normal or Type III fibroblasts. VLDL, IDL, and LDL fractionated by zonal ultracentrifugation from Type III plasma gave half-maximum inhibition at 0.2-0.5 mug of protein/ml, indistinguishable from the suppression caused by normal LDL. Type III VLDL did not suppress HMG-CoA reductase in mutant LDL receptor-negative fibroblasts. Zonally isolated VLDL obtained from one Type IV and one Type V patient gave half-maximal suppression at 5 and 0.5 mug of protein/ml, respectively. Molecular diameters and apoprotein compositions of the zonally isolated normal and Type III VLDL were similar; the major difference in composition was that Type III VLDL contained more cholesteryl esters and less triglyceride than did normal VLDL. The compositions and diameters of the Type IV and Type V VLDL were similar to normal VLDL. These findings show that the basic defect in Type III hyperlipoproteinemia is qualitatively different from the cellular defect found in familial hypercholesterolemia, since the regulation of HMG-CoA reductase activity is normal in Type III fibroblasts. The metabolic defect in hypertriglyceridemia is related to the triglyceriderich lipoproteins which, free of other lipoproteins, have an enhanced ability to interact with cultured fibroblasts to regulate HMG-CoA reductase activity. These studies suggest that, in hypertriglyceridemia, there is a mechanism for direct cellular catabolism of VLDL which is not functional for normal VLDL.     

Differential Sensitivity of Lymphocyte Subpopulations to Suppression by Low Density Lipoprotein Inhibitor, an Immunoregulatory Human Serum Low Density Lipoprotein

Reports by a number of investigators have described the thymus-derived (T)-cell dependence of immunoglobulin synthesis by pokeweed mitogen (PWM) stimulated human peripheral blood bone marrow-derived (B) cells. Because of the cooperative nature of this in vitro system, it was chosen for examination of the differential effects of low density lipoprotein inhibitor (LDL-In) on B- and T-cell functions. Supernates from 7-d cultures that contained either peripheral blood mononuclear cells (PBM) or combinations of isolated lymphocyte populations were assayed for immunoglobulin (Ig)G by competitive inhibition radio-immunoassay. LDL-In suppression of whole PBM IgG synthesis occurred at 5-20 mug protein/ml and was independent of PWM concentration. Maximal suppression required preincubation of cells with LDL-In before stimulation. Suppression was also observed when B cells alone were exposed for 24 h to LDL-In before PWM stimulation; these suppressed B cells were not rescued by normal T cells. Exposure of T cells alone to low doses of LDL-In for 24 h augmented, but high doses suppressed, IgG synthesis, suggesting a differential effect on T-helper vs T-suppressor cell populations. Independent LDL-In exposure of T-helper or T-suppressor cell enriched populations, separated by rosetting with IgG- or IgM-coated ox erythrocytes, identified the T-suppressor cell populations as the most sensitive of the lymphocyte populations tested. The sensitivities of lymphocyte subpopulations to LDL-In, relative to PBM, were 2.8, 1.2, and 0.3 for the T-suppressor cells, B cells and T-helper cells, respectively. Thus, both B and T lymphocytes are sensitive to and can be regulated by LDL-In. In addition, the biologic activity observed when unseparated PBM are exposed to LDL-In appears to represent a composite of the sensitivity of each of the lymphocyte subpopulations.     

Effects of Dietary Polyunsaturated and Saturated Fat on the Properties of High Density Lipoproteins and the Metabolism of Apolipoprotein A-I

In this study we have investigated, in four normal males the effects of dietary saturated and polyunsaturated fat on the chemical composition and thermotropic properties of human high density lipoproteins (HDL) and have measured the influence of the diets on the metabolism of that fraction of HDL apolipoprotein A-I (apoA-I) that undergoes exchange in vitro and accounts for approximately two-thirds of the lipoprotein's apoA-I complement. When compared with the saturated fat diet, the polyunsaturated diet reduced plasma cholesterol (24%, P < 0.01) by affecting the cholesterol content in the very low density lipoprotein ( downward arrow25%, P < 0.02), low density lipoprotein ( downward arrow20%, P < 0.01), and high density lipoprotein fractions ( downward arrow33%, P < 0.01). Plasma triglyceride was also lowered (by 13%, P < 0.01). Furthermore, polyunsaturated fat ingestion caused a significant fall in the palmitate and stearate content of HDL triglyceride (41 and 37%, respectively), cholesteryl esters (29 and 35%), and phospholipids (17 and 9%) with a concomitant increase in the linoleate content of these moieties (157, 28, and 29%, respectively). The polyunsaturated diet also produced reciprocal changes in the percentage protein ( downward arrow9%, P < 0.02) and phospholipid ( downward arrow11.5%, P < 0.01) in HDl. These compositional changes were associated with an increase in the microscopic fluidity of the polyunsaturated HDL, although both diets had little effect on the fluidity parameters of HDL at body temperature. Rate zonal ultracentrifugation indicated that the HDL(2)/HDL(3) ratio fell by 28% (P < 0.05) on the polyunsaturated fat diet. In addition to the above, this diet reduced plasma apoA-I by 21% (P < 0.01). No change was seen in the fractional catabolic rate or the distribution of the apoprotein between intravascular and extravascular compartments on the two diets. However, when compared with the saturated diet, the synthetic rate of apoA-I was reduced by 26% during polyunsaturated fat feeding. The results show that polyunsaturated fat alters the chemical composition, thermotropic properties, and subfraction distribution of HDL without changing the fractional rate of catabolism of their major protein, apoA-I.These findings deserve careful consideration in determining the applicability and efficacy of polyunsaturated fat diet therapy in the prevention of atherosclerosis in man.     

Structure, Immunology, and Cell Reactivity of Low Density Lipoprotein from Umbilical Vein of a Newborn Type II Homozygote

In this report we compare the cord blood lipoproteins of a newborn boy homozygote who has low density lipoprotein (LDL) receptor-defective familial hypercholesterolemia (FH) with the lipoproteins from cord blood of normal newborns. Plasma LDL-cholesterol and apoprotein (Apo)B were 612 and 233 mg/dl (vs. 31±16 and 24±12 mg/dl, respectively, for normals, n = 21). LDL-cholesterol/ApoB ratio was 2.6 vs. 1.4±0.5. Levels of ApoA-I, ApoA-II, and HDL-cholesterol were similar to normal cord plasma. Thus, the lipoprotein abnormality is apparent at birth and is definitely present in LDL. Abnormalities in other lipoprotein, lipid, and in plasma apoprotein levels were not detected. On zonal ultracentrifugation, FH LDL was comprised of two populations (LDL_a and LDL_b), both faster floating than normal cord LDL (LDL_c). This difference was due to the larger diameters of the particles on electron microscopy (LDL_a = 276ű32 and LDL_b = 260ű38 vs. LDL_c = 237ű26, n = 200 each, mean±1 SD), and their higher contents of lipids relative to protein (86 and 82% vs. 74%, LDL_a, LDL_b, and LDL_c, respectively). More than 94% of the protein in both the FH and the normal preparations consisted of ApoB. FH LDL were more effective than control LDL in competing with ¹²⁵I-LDL (adult) for limiting amounts of anti-LDL antibodies in radioimmunoassay. FH LDL also competed more effectively for binding to LDL receptors on cultured fibroblasts at 4°C, and FH LDL also delivered more cholesterol into the cells. Cells grown in lipoprotein-deficient serum contained 44±2 μg cholesterol/mg cell protein, incubation of cells for 18 h at 37°C in 5 μg/ml FH LDL (protein) or in normal LDL raised cellular cholesterol levels to 75±2 and 60±2 μg/mg, respectively.     

The Interaction of Heparin with an Apoprotein of Human Very Low Density Lipoprotein

An arginine-rich apoprotein obtained from human triglyceride-rich lipoprotein was isolated on a heparin affinity column when either the aqueousor urea-soluble apoproteins were applied to the column. Of all the aqueous- or urea-soluble apoproteins, only this arginine-rich protein exhibited a binding affinity to heparin. This protein was eluted from the column at sodium chloride concentrations above 0.35 M in the absence of urea and between 0.17-0.2 M when isolated in urea. The protein has been characterized by amino acid analysis, immunoelectrophoresis, dodecyl sulfate polyacrylamide electrophoresis, isoelectric focusing, and NH(2)-terminal analysis. It has the same amino acid composition, NH(2)-terminal, and molecular weight as previously described for human arginine-rich apoprotein.The triglyceride-rich lipoproteins of fasting normal humans were eluted as two fractions when applied to the heparin affinity column. A small amount was eluted in the unbound fraction and this species contained virtually no arginine-rich apoprotein. The bulk of the triglyceride-rich lipoproteins eluted in the bound fraction and contained appreciable amounts of arginine-rich apoprotein. The bound lipoproteins had more cholesterol and cholesterol ester and less triglyceride than the unbound. The isolated arginine-rich apoprotein was derivatized with phenylglyoxal with a resulting alteration of 75% of the arginine residues. This modified apoprotein did not bind to the heparin affinity column. Similar treatment of the whole triglyceride-rich lipoprotein produced a lipoprotein that was totally eluted in the unbound fraction.     

润肠通便合剂对离体回肠平滑肌的影响研究

目的:观察润肠通便合剂对家兔、豚鼠离体回肠平滑肌的影响。方法:采用动物实验的方法。结果:加入受试药物后豚鼠离体回肠平滑肌先出现短暂的弛缓,然后见兴奋性增加,收缩幅度增加,张力增加,张力提高,高、中、低计量组与空白组比较P<0.05,差异有显著性。结论:润肠通便合剂能兴奋豚鼠离体回肠平滑肌,引起回肠收缩,适用于慢传输型便秘。     

Antibiotic Resistance Patterns of Metal-Tolerant Bacteria Isolated from an Estuary

Estuarine bacteria isolated on metal-containing media were also found to be antibiotic resistant; ampicillin and chloramphenicol were the antibiotics to which resistance was most common. Patterns of antibiotic resistance were found associated with a variety of taxa.     

Studies on Biosynthesis of Antimicrobial Silver Nanoparticles Using Endophytic Fungi Isolated from the Ethno-medicinal Plant Gloriosa superba L.

Two endophytic fungi isolated from the ethno-medicinal plant Gloriosa superba L. were used for the in vitro biosynthesis of silver nanoparticles (AgNPs). The endophytic fungi were identified as Alternaria solani GS1 and Penicillium funiculosum GS2 based on their ITS regions of rRNA gene sequences. The silver nanoparticles obtained were characterized by UV–visible spectroscopy and transmission electron microscopy. Silver nanoparticles of the size 5–20 nm biosynthesized by A. solani GS1were found to be at peak at 415 nm whereas the AgNPs of the size 5–10 nm biosynthesized using P. funiculosum GS2 showed a maximum peak at 403 nm. An evident superiority of the antimicrobial potency, as denoted by the zone of inhibition by biosynthesized AgNPs using P. funiculosum GS2 compared to that by A. solani GS1, was observed when the nanoparticles were used against three different bacterial strains (Streptococcus pyogenes MTCC1925, Escherichia coli MTCC730 and Enterococcus faecalis MTCC2729) and a fungal strain (Candida albicans MTCC183). The present study elucidates the efficacy of the AgNPs synthesized by endophytic fungi against the three tested bacterial strains as well as the fungal strain C. albicans indicating their potency of bioprospection for medicinal usage.     

Prevention of Glomerulonephritis and Prolonged Survival in New Zealand Black/New Zealand White F1 Hybrid Mice Fed an Essential Fatty Acid-deficient Diet

Female B/W mice spontaneously develop an autoimmune disease that is similar to systemic lupus erythematosus. Antibodies to doublestranded DNA (dsDNA) and antinuclear antibodies develop in aging animals; death from immune complex-mediated glomerulonephritis occurs from 8 to 12 mo of age. It has been reported that prostaglandin (PG)E₁ treatment of such mice prolongs survival. In the present study, four groups of female B/W mice were studied beginning at 6-11 wk of age on the following regimens: (a) a synthetic diet that contained 20% safflower oil, (b) a standard laboratory chow diet, (c) a standard diet together with injections of PGE₁, and (d) an essential fatty acid-deficient synthetic diet that contained 20% coconut oil. All animals were tested monthly for antinuclear antibodies and anti-dsDNA. Kidney tissue was obtained for light and immunofluorescence microscopy when animals were dying. All disease manifestations were altered strikingly in the essential fatty acid (EFA)-deficient animals. Intermediate benefit was seen in PGE₁-treated animals. 7% of the control animals and 18% of safflower oil-fed animals survived to 10 mo. In contrast, the PGE₁-treated and EFA-deficient mice had a similar survival rate (78-88%). At age 16 mo, 78% of EFA-deficient mice and 45% of PGE₁-treated mice were alive. 25% of the PGE₁-treated and 55% of the EFA-deficient animals survived to 20 mo. Serum anti-dsDNA appeared at age 5 mo in safflower oil-fed and control animals, but not until 9 and 12 mo for PGE₁-treated and EFA-deficient animals, respectively. All kidneys from 7- to 9-mo-old safflower oil-fed and control animals and the majority of kidneys from PGE₁-treated animals were abnormal by light and immunofluorescence microscopy. Kidneys from EFA-deficient animals were essentially normal at 10 mo. At 13 mo, all PGE₁-treated animals examined had significant kidney involvement, whereas none of the EFA-deficient animals had glomerulonephritis. These findings demonstrate that an EFA-deficient diet has a beneficial effect on murine lupus erythematosus.     

Antioxidant Activity and Lipid-Lowering Effect of Essential Oils Extracted from Ocimum sanctum L. Leaves in Rats Fed with a High Cholesterol Diet

It has been reported that Ocimum sanctum L. (OS) leaves decrease serum lipid profile in normal and diabetic animals. No experimental evidences support the anti-hyperlipidemic and antioxidative actions against hypercholesterolemia. Moreover the identity of the specific chemical ingredients in OS leaves responsible for these pharmacological effects are unknown. Since OS leaves are rich in essential oil (EO). Therefore the present study was conducted to investigate the anti-hyperlipidemic and antioxidative activities of EO extracted from OS leaves in rats fed with high cholesterol (HC) diet. EO was extracted by the hydrodistillation method and the chemical constituents were then identified by Gas Chromatography-Mass Spectrometry. The experiment was performed in Male Wistar rats fed with 2.5 g%(w/w) of cholesterol diet for seven weeks. During the last 3 weeks, rats were daily fed with EO. The results showed that phenyl propanoid compounds including eugenol and methyl eugenol were the major constituents of EO. EO suppressed the high serum lipid profile and atherogenic index as well as serum lactate dehydrogenase and creatine kinase MB subunit without significant effect on high serum levels of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase in rats fed with HC diet. In addition, EO was found to decrease the high levels of thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPx) and superoxide dismutase (SOD) without impacting catalase (CAT) in the cardiac tissue while in the liver, it decreased high level of TBARS without significantly effecting GPx, SOD and CAT. Histopathological results confirmed that EO preserved the myocardial tissue. It can be concluded that EO extracted from OS leaves has lipid-lowering and antioxidative effects that protect the heart against hypercholesterolemia. Eugenol that is contained in EO likely contribute to these pharmacological effects.     

Effects of Intravenous Phospholipid on Low Density Lipoprotein Turnover in Man*

The mechanism of the rise in plasma low density lipoprotein (LDL) levels following intravenous administration of a triglyceride-phospholipid emulsion (Intralipid) has been investigated by measuring LDL turnover in eight healthy subjects. The plasma half-life, and the absolute and fractional catabolic rates of LDL protein (apo-LDL) were unaffected by intragastric Intralipid, whereas apo-LDL half-life was prolonged and its fractional catabolic rate was decreased by intravenous Intralipid. Similar changes were observed after intravenous administration of the egg phospholipid constituent of Intralipid. Accompanying increases in the oleate: linoleate ratio of both high and low density lipoprotein cholesterol esters were secondary to phospholipid exchange between infused and endogenous lecithin. These results suggest that the increased concentration of LDL in plasma following intravenous administration of egg phospholipid-containing emulsions was due, at least in part, to a decrease in the fractional catabolic rate of apo-LDL. The data further suggest a possible relationship between apo-LDL catabolism and the fatty acid composition of LDL.     

Isolated perfusion of extremities for metastatic melanoma from an unknown primary lesion

Since 1957, 822 patients with invasive malignant melanoma of the limbs were treated by regional perfusion at the Tulane Medical Center. Between 1958 and 1982, there were 32 patients with regional metastatic melanoma from an unknown primary site involving either the upper limb and axillary lymph nodes or lower limb and femoral or inguinal lymph nodes. This group represents 3.5% of patients with regional melanomas treated during this period. There were 16 patients with upper limb regional metastases and 14 patients with lower limb metastases. Sixteen patients had stage IIIB disease (ie, regional lymph node metastases), ten had stage IIIA disease (ie, satellitosis), and four had stage IIIAB disease. Six patients had a history of a suggestive limb lesion that had completely regressed and showed no residual tumor on biopsy. All 30 patients were treated by regional isolated perfusion and regional lymph node dissection, with surgical excision of in-transit disease when possible. The cumulative five-year survival for all patients is 50%. Interestingly, the patients with a history of a lesion that regressed had 85% cumulative five-year survival, and the patients with stage IIIB disease did almost as well, with 62% surviving for five years.     

Studies on Human Serum High-Density Lipoproteins (HDL) IV. Isolation of Lipoprotein Families after Incubation of HDL

The high-density lipoproteins (HDL) of human serum appear to be unstable and easily exposed to chemical changes during isolation. In earlier studies we have isolated and purified HDL subtractions either in the presence of an SH-blocking agent, DTNB, or in the cold. By both procedures reproducible lipoprotein subfractions could be recovered by hydroxyl apatite column chromatography at the elution steps 0.03–0.05 mol/1 (subfraction II) and 0.05–0.15 mol/1 phosphate buffer (subfraction III). The protein moiety of both lipoprotein subfractions contained polypeptides A–I, A–II, thin line (TL), C–I and C–II, and the protein moiety of subfraction III contained also C–III. The incubation at 37°C of these HDL subfractions gave reproducible daughter lipoprotein fractions that could be recovered by subsequent rechromatography on hydroxyl apatite. At each of the elution steps 0.05–0.075 mol/1 and 0.075–0.10 mol/1 one daughter fraction was recovered, the protein moiety of which was composed of polypeptide A–I, as judged by polyacrylamide gel electrophoresis, immunodiffusion, and amino acid analysis. The incubation of parent subfractions II and III caused also the appearance at elution step 0.001–0.01 mol/1 of a daughter lipoprotein fraction-lipoprotein A (Lp-A)-that was characterized by a protein moiety with polypeptides A–I and A–II in equal amounts. The ‘release’ of lipoprotein A–I (Lp-A-I) and Lp-A was shown to be due rather to the incubation than to the column chromatography as such. The chemical changes occurring during the incubation of HDL suggested a degradation of phosphatidylcholine (PC) to lysophosphatidylcholine (lyso-PC) and glycerylphosphorylcholine (GPC). It is suggested that the degradation of PC might interfere with the interaction between the lipoprotein families composing HDL.