Showing papers in "Journal of Clinical Biochemistry and Nutrition in 1989"

Novel Liposomes for Efficient Transfection of β-Galactosidase Gene into COS-1 Cells

Abstract: A pCH 110 plasmid encoding the β-galactosidase gene of E. coli was effectively entrapped in novel positively charged liposomes consisting of N-(α-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine (1:2:2, molar ratio) by an improved reverse-phase evaporation method. The DNA entrapping efficiency of these liposomes was 5-70 fold higher than that of liposomes containing no positively charged lipid. By using such positively charged liposomes, we could achieve transfection of the gene into COS-1 cells by simply adding the liposomes to the medium covering the cells; and the transfection efficiency exceeded that obtained by the calcium phosphate precipitation method, especially when a small amount of DNA was used.

An Improved Method for Entrapment of Plasmids in Liposomes

Abstract: The reverse-phase evaporation method [Szoka, F., Jr., and Papahadjopoulos, D. (1978): Proc. Natl. Acad. Sci. USA., 75, 4194-4198] was modified to enable the preparation of liposomes entrapping plasmids without damage to DNA strands due to sonication. In our procedure, reverse-phase micelles were prepared first by sonication and then plasmids were added to form liposomes entrapping plasmids. The efficiency of the liposomes for entrapping of DNA by the present method was higher than that by the original method. By the present method, circular-pCH 110 was entrapped in liposomes without damage, while by the original method, some of the plasmids were cut during the preparation. The expression of the β-galactosidase gene encoded in plasmid pCH 110 was detected in COS-7 cells when the gene was transferred with the liposomes prepared by the present method, but not with the vesicles prepared by the original method.

Influence Dietary Riboflavin Deficiency on Lenticular Glutathione Redox Cycle, Lipid Peroxidation, and Free Radical Scavengers in the Rat

Abstract: Effect of dietary riboflavin deficiency on rat lens glutathione, glutathione redox cycle, and oxidative-antioxidative processes was investigated to understand the possible biochemical mechanism(s) responsible for aggregation of lens proteins. Induction of riboflavin deficiency resulted in a marked reduction in the activity of glutathione reductase (GSH-R). Levels of glutathione (both reduced and oxidised) and sulfhydryl groups (total and non-protein), however, were unchanged. Activity of glucose 6-phosphate dehydrogenase, which generates the reducing equivalents, NADPH, necessary for maintenance of normal GSH-R activity, was found to be unaltered. On the other hand, glutathione dependent glutathione peroxidase, a potent peroxide scavenging enzyme, showed a significant rise in its activity with a concomitant increase in lipid peroxidation. Among the other antioxidative systems studied, superoxide dismutase and catalase remained unaltered, while levels of ascorbate declined.These results indicate impairments in the glutathione redox cycle and antioxidative defence mechanisms, in addition to enhanced lipid peroxidation in the lens of riboflavin deficient rats.

Effect of Ovariectomy on Serum and Liver Lipid Peroxide Levels of Female Mice

Abstract: When bilateral ovaries were removed from 12-13-week-old female mice, serum lipid peroxide levels of the animals tended to increase at 1 month after the ovariectomy, and significantly higher levels compared with those of sham-operated control mice were observed at 2 and 3 months after the operation. Liver lipid peroxide levels of the ovariectomized mice were significantly increased at 1 month after the operation and high levels were also observed at 2 and 3 months after the operation. The increase in serum and liver lipid peroxide levels due to ovariectomy was suppressed by the subcutaneous administration of 17β-estradiol or 2-hydroxyestradiol. From these results, we propose that female hormones may play an important role in preventing an increase in lipid peroxide levels in women.

Effect of Ascorbic Acid on Antioxidant Defense Systems and Lipid Peroxidation in Guinea Pig

Abstract: In view of the antioxidant properties of ascorbic acid (AA), effects of inadequate and excessive doses of AA on hepatic and pulmonary antioxidant enzymes and NADPH-dependent lipid peroxidation were investigated in the present study. Male guinea pigs, dosed daily with 0.2mg AA/100g b wt (inadequate) or 50mg AA/100g b wt (excessive) for 8 weeks, demonstrated no difference in body growth, liver and lung weights, and post-10, 000×g supernatant protein contents as compared with the control group, which was daily fed with 2mg AA/ 100g b wt. Inadequacy of AA decreased the hepatic and pulmonary contents of catalase, glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), but it significantly increased glutathione reductase (GR) activity (p<0.005) in lung. However, levels of hepatic and pulmonary NADPH-dependent lipid peroxidation remained unaltered when the supply of AA was inadequate. Excessive doses of AA did not influence any pulmonary antioxidant enzyme, level of NADPH-dependent lipid peroxidation and content of reduced glutathione (GSH), but increased the hepatic GSH-Px and GR activities. Hepatic SOD activity showed a significant decrease (p<0.01), whereas NADPH-dependent lipid peroxidation and GSH contents remained unchanged. It appears that the changes in antioxidant enzymes may be a nonspecific response to AA or these changes may not be sufficient to bring about any shift in the levels of NADPH-dependent lipid peroxidation in the presence of unaltered GSH contents or other biomolecules which may act as antioxidants or free radical scavengers in the cell system.

Effect of Zinc-Carnosine Chelate Compound (Z-103) on Burn-Induced Gastric Mucosal Injury in Rats

Abstract: The protective effect of a novel synthetic zinc-carnosine chelate compound, zinc N-(3-aminopropionyl)-L-histidine (Z-103), on the gastric injury induced by burn stress was studied in rats. Gastric lesions were produced by immersion of half of the animal's body into 80°C water for 10s. The increase in total area of the erosions 3h after the stress and the increase in thiobarbituric acid reactants in the gastric mucosa were significantly inhibited by the administration of Z-103 at doses of 30, 100, and 300mg/kg. The decrease in blood flow in the gastric mucosa was not influenced by the treatment with Z-103. These results suggest that the protective effect of Z-103 against the aggravation of burn-induced gastric mucosal injury may be due to its inhibitory effect on lipid peroxidation.

What do thiobarbituric acid and hemoglobin-methylene blue tests evaluate in the endogenous lipid peroxidation of rat liver?

Abstract: To detect the endogenous lipid peroxides in rat liver, the thiobarbituric acid (TBA) and hemoglobin-methylene blue (HMB) tests were used. The endogenous lipid peroxidation in rat liver was induced by peroxidative drugs, and then these tests were carried out. When CCl4, paraquat or phenobarbital was intraperitoneally injected, the HMB values were significantly increased only at the early period after the doses (1h), whereas two peaks of TBA value were observed at 1h and around 24h after the doses. When peroxidation was induced by thiopental or alcohol, the TBA value also gave two peaks. It was suggested that the agreement between detections by both HMB and TBA (the early peak) indicated the peroxide formation, and that the independent increase in TBA value (second peak) the accumulation of aldehydes in the liver. The life span of HMB-reactive substances was short in vivo compared with that of the TBA-reactive substances. It is considered that the TBA test was useful to detect the endogenous lipid peroxidation under the conditions that TBA test could detect aldehydes originating from lipid peroxidation because lipid peroxides were unstable in vivo.

Serum Lipid Peroxides and Cataractogenesis in Riboflavin Deficiency

Abstract: When young male Wistar rats were fed a diet containing a minute amount of riboflavin, the blood level of each of flavin adenine dinucleotide, flavin mononucleotide, and riboflavin was decreased after 1 week of feeding and remained low after 2 and 3 weeks of feeding Glutathione reductase activities in the liver and erythrocytes were decreased after 2 weeks of feeding Then, a significant increase in serum lipid peroxide level was observed one week later In accordance with the increase in serum lipid peroxides, incipient electron microscopic changes occurred in the lenses of the rats, ie, swelling of mitochondria in the epithelial cells and the appearance of vacuoles in the fibers The vacuoles became larger after 6 weeks of feeding on the diet The administration of linoleic acid hydroperoxide to rats fed the diet containing a minute amount of riboflavin brought about a further increase in serum lipid peroxide level, and the number of vacuoles formed in the lens fibers was increased and their size became larger These findings support the view that lipid peroxides increased in the blood are the cause of cataractogenesis

Therapeutic Effect of Chlorin e6Na as a New Photosensitizing Agent in Photodynamic Therapy of Mouse Tumor

Abstract: Chlorin e6Na (Chl), a hydrophilic chlorophyll derivative structurally similar to pheophorbide a (Pheo), had less cell-killing effect on FM3A cells than Pheo. Its cell-killing effect was suggested to be based on the damage of the cell membrane through the same mechanism as that of Pheo, because Chl was distributed mainly in the plasma membrane fraction.The time required for the maximum build-up of Chl in FM3A tumor tissue after injection was 2-8h. The photodynamic therapy (PDT) at 6 or 24h following administration of Chl caused shorter survival of FM3A tumor-bearing mice in comparison with that obtained when Pheo was used. However, the tumor-to-organ ratios of Chl at 24h after injection were higher than those of Pheo, and Chl was excreted more rapidly from normal tissues than from tumor tissue and had little phototoxicity on normal organs. From these characteristics, Chl may be more suitable as a photosensitizing agent in PDT than Pheo.

Carbon Tetrachloride-Induced Alteration of Glutathione S-Transferase in Rat Liver Cytosol and Plasma

Abstract: Effects of carbon tetrachloride (CCl4) administration on hepatic and plasma glutathione S-transferase (GST) activity were studied in rats under both acute and chronic phases. Intraperitoneal administration of CCl4 at a high dosage (1.2ml/kg) (acute group) resulted in a marked elevation of plasma GST activity (over 200-fold of the control level at 24h after the administration) that was accompanied by a decrease in hepatic GST activity. In contrast to the successive elevation of plasma GST activity which had not reached a plateau by even 24h, plasma GPT activity reached a maximum at 6h after CCl4 administration and thereafter decreased to under the control value. Results for substrate specificity of plasma GST suggested that the leakage of hepatic GST into plasma began with by type 1-2 GSTs mainly and continued with not only type 1-2 GSTs but also type 3-4 ones. Supporting this assumption, immunohistochemical analyses of hepatic GSTs showed that the leakage of the GSTs occurred at the centrilobular zone where type 1-2 GSTs were shown to localize dominantly in the normal rat liver. And the leakage developed time-dependently to the surrounding area where both types of GSTs were diffusely distributed. Typical massive cell necrosis also developed in the same region. On the other hand, in the group administered repeatedly with a low dosage (0.4ml/kg) (chronic group), drastic alteration of GST activity and also GST localization could not be observed. These results indicate that elevation of plasma GST activity parallels to quantitative and qualitative alteration of hepatic GSTs as well as the extent of the liver damage in the acute phase. Measurement of plasma GST activity may provide useful information to judge the extent of acute liver damage clinically.

Lipid Peroxide Concentration, Selenium Level, and Glutathione Peroxidase Activity in Blood of Type II (Non-Insulin-Dependent) Diabetic Elderly People

Abstract: The lipid peroxides in terms of malondialdehyde concentration, glutathione peroxidase activity and selenium level were determined in the blood of 22 elderly non-insulin-dependent diabetics of both sexes. The results were compared with the values obtained for 43 healthy persons of the same age. The lipid peroxide concentration in plasma and selenium level in whole blood and plasma were the same in both diabetics and controls. In the diabetes group a nonsignificantly lower (7%) selenium concentration in red blood cells was observed, whereas the glutathione peroxidase activity in erythrocytes of the patients tested was statistically lower (p<0.02) as compared with normals. In plasma, activity of this enzyme was increased by 14% as compared with healthy people, but without statistical significance. We found that selenium excretion in the urine found was significantly higher in the diabetics than in healthy people. We found a statistically significant, linear correlation (r=0.435, p<0.05) between enzyme activity and lipid peroxide concentration in plasma, and between plasma and urine selenium levels (r=0.937, p<0.001) in diabetes.

Serum Levels of Tocopherol and Their Relationship to Risk Factor of Coronary Heart Disease in University Students

Abstract: This study assessed the biochemical status of serum α-tocopherol (Toc) and lipid in university students (60 males and 51 females) and searched for risk factors of coronary heart disease (CHD). No significant differences were observed between the sexes in total cholesterol (T-C) (170 and 181mg/100ml for males and females, respectively), low density lipoprotein-cholesterol (LDL-C) (116 and 118mg/100ml), and phospholipids (PL) (193 and 199mg/100ml). The levels of high density lipoprotein-cholesterol (HDL-C) were lower in males (54mg/100ml) than in females (62mg/100ml, p<0.001) and those of triglyceride (TG) were higher (74 and 59mg/100ml for males and females, respectively, p<0.01). There were also no significant differences in HDL-C as a percentage of T-C (32 and 35%) and the LDL-C/HDL-C ratio (2.3 and 2.0). Toc level and the Toc/T-C ratio were significantly lower in males (5.16μg/ml and 3.11μg/mg, respectively) compared with females (6.15μg/ml and 3.46μg/mg, respectively) (p<0.001 for Toc and p<0.05) for Toc/T-C. A direct relationship was found between the T-C level and LDL-C (r=0.92, p<0.001) and HDL-C (r=0.40, p<0.001). The atherogenic index, the LDL-C/HDL-C ratio, showed a positive correlation with the T-C level (r=0.43, p<0.001) and a negative correlation with the HDL-C level (r=-0.63, p<0.001). The T-C levels also could be correlated with the levels of Toc (r=0.37, p<0.001) and inversely correlated with the Toc/T-C ratio (r=-0.41, p<0.001). The Toc/T-C ratio showed an inverse correlation with the LDL-C/HDL-C (r=-0.31, p<0.001). These results reveal that the T-C level affects the vitamin E status and that the Toc/T-C ratio can be used to assess trends in CHD risk factors.

Circumvention of Adriamycin-Resistance of Leukemia Cells by the Anti-Allergic Drug Azelastine

Abstract: The effects of the anti-allergic drug azelastine on the P388 murine leukemia cell line (P388) and the K562 human leukemia cell line (K562) and their adriamycin (ADM)-resistant sublines P388/ADM and K562/ADM were examined with respect to the cytotoxic effect, cellular accumulation and retention of ADM. Azelastine enhanced the cytotoxicity of ADM toward P388 and K562 cells slightly but toward P388/ADM and K562/ADM cells greatly. Azelastine was found to increase the intracellular levels of ADM in both P388/ADM and K562/ADM cells by inhibiting the outward transport of the drug. The high intracellular accumulation of ADM accounts for the enhancement of the cytotoxicity of ADM, and thus the ADM-resistance of these cells was partially circumvented.

Effects of Gamma-Linolenic Acid Supplementation on Lipid Composition of Liver Microsomal Membranes

Abstract: The effects of gamma-linolenic acid on essential fatty acid metabolism has been studied in fetuses from pregnant rats fed a zinc-deficient diet and in those from pregnant rats fed a balanced diet. Gamma-linolenic acid supplementation was in the form of evening primrose oil (EPO), and the study of lipid metabolism was carried out in liver microsomes. Pregnant rats were fed one of four diets: zinc-deficient (ZD), zinc-deficient+evening primrose oil (ZD+EPO), zinc-adequate (Control, C), and zinc adequate+evening primrose oil (C+EPO).In control groups (C and C+EPO) and deficient groups (ZD and ZD+EPO), gamma-linolenic acid supplementation had no effect on either zinc concentration in liver or Δ6 desaturation. All products of in vivo Δ6 desaturation were also not modified. Gamma-linolenic acid supplementation did not have much effect on essential fatty acid metabolism or on the distribution between n-6 and n-3 polyunsaturated fatty acid families. It was noticed, however, that the phosphatidylcholine level was enhanced and that the phosphatidylethanolamine level was decreased.The results indicate that in fetuses from pregnant rats fed a zinc-deficient diet the gamma-linolenic acid supplementation affects more the distribution of phospholipids in microsomal membranes than fatty acid profiles.

Histopathological Changes in Spontaneously Hypertensive Rats after Feeding of Shiitake ( Lentinus edodes ) and Maitake ( Grifola frondosa ) Mushroom Diets

Abstract: Histopathological changes in spontaneously hypertensive rats were studied after the animals had been fed Shiitake (Lentinus edodes) and Maitake (Grifola frondosa) mushroom powder diets, with 0.5% NaCl solution as drinking water for 9 weeks. Histological changes in control and Shiitake-fed rats were essentially the same, consisting of necrosis of the medial smooth muscle cells, vacuolization in the media of the aorta, fatty liver development, maceration in the myocardial muscle cells and vacuolization in the myocardium. In Maitake-fed animals large amounts of glycogen were observed in the liver, but the animals were otherwise normal in all respects. Dietary Maitake seems to play an important role in preventing the histological degenerative changes in SHR and thus may imply some benefits to be gained through blood pressure reduction and an improvement of lipid metabolism.

Dietary Intake and Other Determinants of Iron and Folate Status in Female Adolescents

Abstract: The relationships of diet, development, and maturation indices to the status of blood iron and folate indicators were studied among 233 adolescent girls aged 10-16 years. Statistically significant associations between total iron intake and hemoglobin, plasma iron, serum ferritin and transferrin saturation were observed after controlling the confounding effect of other parameters. Iron intake provided by meat was positively related to hemoglobin and serum ferritin levels. Moreover, post-menarcheal girls and girls in their growth spurt peak had a lower serum ferritin level than the others. Plasma and erythrocyte folate levels increased with increasing folate intake from vegetables and fruits. Plasma folate level decreased with decreasing folate from meat. Plasma and erythrocyte folate levels decreased with chronologic age independantly of dietary intake. Among this nutritionally vulnerable group, our results specify the effect of factors known to influence iron and folate status.

Beneficial Effect Polyunsaturated Fatty Acid-Supplemented Diet on Altered Composition of Plasma Fatty Acids in Patients with Liver Cirrhosis

Abstract: For normalization of the low levels of plasma polyunsaturated fatty acids (PUFA), a PUFA-supplemented diet including fishes and safflower oil was served for two weeks to nine patients with decompensated cirrhosis, whose linoleic, α-linolenic, arachidonic, eicosapentaenoic and docosahexaenoic acid levels in the plasma total lipid fractions were significantly low. Linoleic and eicosapentaenoic acid concentrations in the plasma total lipid fractions and eicosapentaenoic acid in the plasma phospholipid fractions were significantly increased following the administration of the PUFA-supplemented diet to these patients. Increases in relative composition of dihomo-γ-linolenic and eicosapentaenoic acids were also recognized in the plasma total lipid fractions. However, α-linolenic, arachidonic, and docosahexaenoic acids were not altered either in the plasma total lipid or phospholipid fractions. Clinical data such as serum glutamate-pyruvate transaminase activity and bilirubin levels showed no change during PUFA-supplemented diet. Supplementation with arachidonic acid itself to the diet, as well as fishes and vegetable oil, seems to be necessary to maintain normal composition of plasma fatty acids in patients with decompensated cirrhosis.

Determination of serum lipid peroxide levels in healthy and diseased subjects by use of a methylene blue derivative.

Abstract: By using a newly developed assay method for lipid peroxides based on their reaction with a leucomethylene blue derivative, we investigated serum lipid peroxides (LPO) in healthy and in diseased subjects. In 116 healthy subjects, the mean LPO level obtained was 1.45±1.37nmol/ml and showed significant correlations with total bilirubin, direct bilirubin, phospholipid, total cholesterol, high density lipoprotein-cholesterol, and low density lipoprotein-cholesterol. In 12 hypertensive patients, the LPO value was significantly higher (2.60±2.08nmol/ml) compared with the healthy control, and LPO showed a significant correlation with serum globulin. In 16 hyperlipidemic subjects, the value was 1.50±0.86nmol/ml and correlated with fibrinogen, white blood cells, and nonesterified fatty acids. In 19 diabetics, the level was not significantly different with that in the healthy control, and correlated with fasting blood sugar, total protein, and urea nitrogen. In 10 patients with liver dysfunction, LPO was 1.60±1.33nmol/ml and correlated with white blood cells, chloride, and nonesterified fatty acids.

Effect of gari diet on the pathological changes of the aorta, liver, and kidneys of rats.

Abstract: The effects of feeding of an experimental diet consisting of 16 and 32% of gari by weight were compared with those of the gari-free, control diet in rats. The experiment was carried out for a period of six months during which two rats from each group (A, control; B, 16% gari incorporation; and C, 32% gari incorporation) were killed for histological study. Histological examination of the aorta, liver, and kidneys revealed degenerative changes in group B and C rats, as evidenced by vacuolation and accumulation of periportal fat. These manifestations started at the third month of the experiment. At the fourth month there was massive degeneration of the arterial wall linings followed by development of fatty streaks in the lumen of the arteries.

In Vivo Lipid Peroxidation in Chickens as Measured by Pentane Production Rate

Abstract: Monitoring of expiratory pentane was used as a non-invasive method to measure endogenous lipid peroxidation in chicken for the first time. Pentane is generated during breakdown of ω6-fatty acid hydroperoxides. Main problems with this method are the simultaneous metabolism of the hydrocarbons and the alkanes of intestinal origin. To overcome these limitations we performed kinetic studies for calculation of the actual production while taking into account the effect of metabolism. The influence of intestinal pentane was investigated by using fasted animals. Iron injection was employed to enhance endogenous lipid peroxidation. Under the conditions of a feeding experiment, pentane production rates were increased in animals brought up on oxidized fat, and dietary vitamin E reduced this effect. The influence of the intestinal hydrocarbons on pentane production rates were minimized by using fasted animals, as most of the pentane produced in fed animals originates from the gut.

Effects of Gamma-Linolenic Acid Supplementation on Lipid Composition of Liver Microsomal Membranes:I. Pregnant Rats Fed a Zinc-Deficient Diet and Those Fed a Balanced One

Abstract: The effects of gamma-linolenic acid on essential fatty acid metabolism has been studied in fetuses from pregnant rats fed a zinc-deficient diet and in those from pregnant rats fed a balanced diet. Gamma-linolenic acid supplementation was in the form of evening primrose oil (EPO), and the study of lipid metabolism was carried out in liver microsomes. Pregnant rats were fed one of four diets: zinc-deficient (ZD), zinc-deficient+evening primrose oil (ZD+EPO), zinc-adequate (Control, C), and zinc adequate+evening primrose oil (C+EPO).In control groups (C and C+EPO) and deficient groups (ZD and ZD+EPO), gamma-linolenic acid supplementation had no effect on either zinc concentration in liver or Δ6 desaturation. All products of in vivo Δ6 desaturation were also not modified. Gamma-linolenic acid supplementation did not have much effect on essential fatty acid metabolism or on the distribution between n-6 and n-3 polyunsaturated fatty acid families. It was noticed, however, that the phosphatidylcholine level was enhanced and that the phosphatidylethanolamine level was decreased.The results indicate that in fetuses from pregnant rats fed a zinc-deficient diet the gamma-linolenic acid supplementation affects more the distribution of phospholipids in microsomal membranes than fatty acid profiles.

Chemotactic Factor for Polymorphonuclear Leukocytes Derived from Human Lung Giant Cell Carcinoma Lu65 Cells

Abstract: A chemotactic factor for polymorphonuclear leukocytes was found in the culture fluid of human lung giant cell carcinoma cell line Lu65. This factor was defined as chemotactic one by checkerboard analysis. Partial purification of the chemotactic factor was performed by DEAE-Sepharose and gel filtration with Sephadex G-100, which showed it to be basic and low molecular weight. The factor was also found in the filtrate of culture fluid passed through a Centriflo CF25 filter, thus indicating a molecular weight of less than 25kDa. Furthermore, three cell clones having higher activity of chemoattractant were selected from the original cell line.

Urinary Acid Profiles in Asymptomatic and Symptomatic Siblings with Propionyl CoA Carboxylase Deficiency

Abstract: Urinary organic acid profiles of a 12 year-old asymptomatic boy and his 14-year-old symptomatic male sibling were studied by means of gas chromatography-mass spectrometry, and both were chemically diagnosed as having propionic acidemia. The elder brother had developed frequent hyperammonemic attacks during infancy, while the younger had always been asymptomatic. The asymptomatic boy excreted diagnostic metabolites in quantities similar to those of his elder brother. Our observations indicate that propionyl CoA carboxylase deficiency is reflected in urinary organic acid profiles even in an asymptomatic case, and emphasize the importance of investigating the urinary organic acids of asymptomatic siblings of a propionic acidemia patient, especially when their urinary glycine levels are significantly elevated.

Lipid peroxide damage to the retina of albino rabbits.

Abstract: Lipid hydroperoxides (LHP) were synthesized from linoleic acid and injected into the eyes of albino rabbits. This produced a decline in electroretinographic (ERG) activity, a corresponding loss of key molecules localized in the photoreceptor outer segments, and formation of new compounds related to oxidative damage. During the first 2 days of the experimental period, a rapid and irreversible drop in protein, phospholipid, total polyunsaturated fatty acids, vitamin A, and α-tocopherol was observed. This change was so complete that retinal tissue lacked sufficient substrate to undergo any further oxidative stress. Following this initial event, there was an increase in the level of a compound with properties similar to those of the injected LHP, which suggests a propagation phenomena. Corresponding increases in other products of LHP metabolism and formation of conjugated fluorescent pigments also occurred. In response to the oxidative insult, antioxidant enzymes such as peroxidase and glutathione-S-transferase and lysosomal enzymes in general showed changes, but at different time intervals. Thus, an early rise at 2 days post-injection was seen in peroxidase, whereas the rise in transferase activity occurred at 14 days and remained elevated. Lysosomal enzymes rose sharply at 2 days and stayed above baseline levels over the following 2-week period. The present study has demonstrated the LHP are capable of producing severe damage to the retina and are the cause of decreased ERG activity in this type of degeneration.

Relationships among Plasma Lipids, Lipoproteins, and Platelet Aggregation Profiles in Diabetes

Abstract: We compared plasma lipids, lipoproteins, platelet aggregation, plasma lipase activity, age, and body mass index (BMI) between patients with non-insulin-dependent diabetes mellitus and non-diabetic controls. Diabetic subjects showed significantly higher levels of plasma total triglycerides (TG) and very-low-density lipoprotein cholesterol (VLDL-C) and significantly increased platelet aggregability. The total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio was also significantly higher consequent to the significantly lower HDL-C levels in the diabetic subjects when compared with non-diabetic controls. The diabetic group showed positive significant correlations between TC and low-density lipoprotein cholesterol (LDL-C), HDL-C and plasma lipase activity, and TG and TC/HDL-C ratio, whereas significant inverse correlations were observed between TG and HDL-C, HDL-C and TC/HDL-C ratio. Platelet aggregation did not correlate significantly with any of the metabolic variables studied in this group.

Anti-Atherosclerotic Effects of Probucol on Rabbits Differ between Fast Growers and Slow Growers

Abstract: The anti-atherosclerotic effect of probucol was tested on weaned male New Zealand white rabbits. The rabbits, weighing 2kg, were first fed regular rabbit food ad libitum; and when their weight reached 3kg, they were placed on one of the following diets for 10 weeks: 1% cholesterol and 1% probucol rabbit food diet, or 1% cholesterol and regular rabbit food diet. At the end of the experiment we found that the presence of probucol in the diet reduced the level of plasma cholesterol and increased the resistance of low density lipoprotein to oxidation, whereas the drug had no significant beneficial effect of reducing the area of the aorta occupied by atherosclerotic plaques. When the data were probed further, it became apparent that the area of atherosclerotic plaques of the probucol/cholesterol-fed rabbit group was bimodal in distribution. In one subgroup of these rabbits, whose body weight reached 3kg between 6 and 8 weeks (fast grower) during the conditioning period, the area of atherosclerotic plaques (91.0±1.8% of total aortic surface) was the same as that of the cholesterol-fed fast growers (81.8±8%). In the other subgroup of rabbits, whose body weight reached 3kg between 10 and 11 weeks (slow grower) during the conditioning period, the area of atherosclerotic plaques (37.6±6.2%) was significantly (p<0.05) less than that of the cholesterol-fed slow growers (66.4±11.1%). In the comparison of the fast and slow growers on the probucol diet, the rate of weight gain was the only significant difference found. These observations suggest that the anti-atherosclerotic effect of probucol depends upon the rate of weight gain and that the effect may be mediated by an unknown mechanism.