Insulin resistance and enhanced protein glycation in men with prehypertension.

BACKGROUND: Insulin resistance and hyperinsulinemia have been reported among patients with hypertension. However, little is known about insulin sensitivity in subjects with prehypertension. The aim of this study was to assess whether the metabolic characteristics of insulin resistance syndrome are present in prehypertensive subjects. METHODS: Plasma fasting glucose, lipid profile, glycated hemoglobin, fructosamine and insulin concentrations were evaluated in 35 prehypertensive subjects and in 30 healthy controls. RESULTS: Prehypertensive subjects had significantly higher levels of plasma insulin and triglycerides compared with normotensive subjects. The level of high-density lipoprotein cholesterol was significantly lower in prehypertensive subjects compared with controls. There was no significant difference in total cholesterol and low-density lipoprotein cholesterol levels. The levels of glycated hemoglobin and fructosamine were also significantly higher in prehypertensive subjects compared with controls. Plasma insulin levels were positively correlated with systolic and diastolic blood pressure in prehypertensive subjects. Similarly, plasma insulin was significantly positively correlated with triglyceride and negatively correlated with high-density lipoprotein cholesterol. CONCLUSIONS: The present study indicates that prehypertensive non-diabetic subjects have higher insulin resistance and protein glycation compared to normotensive subjects, which may contribute to the pathogenesis of prehypertension.     

Type 1 (insulin-dependent) versus Type 2 (non-insulin-dependent) diabetes mellitus: characterization of serum lipoprotein alterations

Serum lipoprotein lipids and apolipoproteins A-I, B, and E were investigated in Type 1 (insulin-dependent) diabetics, Type 2 (non-insulin-dependent) diabetics, and two control groups, twenty subjects each. Lipoproteins were separated and analysed by common methods, apolipoproteins were measured by endpoint immunonephelometry. Compared with controls, Type 2 diabetics had increased serum apolipoprotein E levels (0.116 +/- 0.020 vs. 0.079 +/- 0.014 g 1-1, P less than 0.01) together with an increased content of cholesteryl ester-enriched very low-density lipoproteins. Furthermore, Type 2 diabetics had higher apolipoprotein B concentrations (1.06 +/- 0.21 vs. 0.85 +/- 0.21 g l-1 P less than 0.01), but lower high-density lipoprotein cholesterol concentrations than the controls. Conversely, Type 1 diabetics had elevated serum apolipoprotein A-I values vs. controls and Type 2 diabetics (1.70 +/- 0.33 vs. 1.49 +/- 0.22 and 1.43 +/- 0.21 g 1-1, P less than 0.01). It is concluded that Type 2 diabetics, like other groups at risk for atherosclerotic diseases, are characterized by an increased concentration of partly catabolized very low-density lipoproteins. Sufficiently insulinized Type 1 diabetics have, on the other hand, an increased number of high-density lipoprotein particles.     

Serum lipids and apolipoproteins in patients with psoriasis.

Psoriasis is characterized by defects in the normal cycle of epidermal development that lead to epidermal hyperproliferation, altered maturation of skin cells, vascular changes and inflammation. Also, psoriasis has been associated with an abnormal plasma lipid metabolism. Changes in plasma lipid and lipoprotein composition in patients with psoriasis may be the reason for the increased risk of atherosclerosis in these patients. We determined serum concentrations of lipids, lipoproteins and apolipoprotein Al and B (apo A1 and apo B) in 72 patients with psoriasis and 30 age matched controls. Serum lipoprotein (a) (Lp(a)), apo A1 and apo B were measured by immunoprecipitation assays, and the lipids and other biochemical parameters by enzymatic methods. Serum Lp(a) and triglyceride (TG) were significantly higher in patients with psoriasis than in healthy control subjects (p<0.01 for both). Apo B was also found to be higher in the patient group, but the difference was not significant. The levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and apo A1 did not differ significantly from those of the controls. These observations imply that serum Lp(a) and TG concentrations may play a role as risk factors for atherosclerotic disease in patients with psoriasis.     

Prevention of Hypercholesterolemic Atherosclerosis by Garlic, an Antixoidant

BACKGROUND: Investigations of the effects of high cholesterol diet in the presence and absence of garlic on the genesis of atherosclerosis, the blood lipid profile, aortic tissue lipid peroxidation product malondialdehyde, chemiluminescence, a marker for antioxidant reserve and activity of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase were made in rabbits. METHODS AND RESULTS: Four groups of 10 rabbits each were studied: group 1 was given regular rabbit chow, group 2 was given rabbit chow diet supplemented with garlic powder (300 mg twice daily orally), group 3 was given 1% cholesterol diet, group 4 was given 1% cholesterol diet supplemented with garlic powder (300 mg twice daily orally). Blood concentration of triglyceride, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and very low-density lipoprotein cholesterol were measured before and after 4 and 10 weeks of experimental diets. The aorta was removed at the end of protocol (10 weeks) for assessment of atherosclerotic changes (gross and microscopic), malondialdehyde concentration, chemiluminescence, and activity of antioxidant enzymes. Total cholesterol, low density-lipoprotein cholesterol and ratio of low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and ratio of low-density lipoprotein cholesterol/high-density lipoprotein cholesterol increaserd in group 3 and 4; the increase was smaller in group 4 than in in group 3 although not significant. Serum high-density lipoprotein cholesterol decreased to a similar extent in groups 3 and 4. Serum triglyceride and very low-density lipoprotein cholesterol remained unchanged in group 3 but increased in group 4. These values were significantly higher than those in group 1. Garlic in rabbits with control diet decreased the levels of triglyceride and very low density lipoprotein but did not affect the levels of total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol and the ratio of low-density lipoprotein cholesterol/high-density lipoprotein cholesterol. There was an increase in aortic tissue malondialdehyde, chemiluminescence, and activities of catalase and glutathione peroxidase in group 3 compared with those in group 1. Levels of aortic malondialdehyde, chemiluminescence, catalase, and glutathione peroxidase were lower in group 4 compared with group 3; however, values for malondialdehyde and chemiluminescence were lower and that of catalase and glutathione peroxidase were higher in group 4 compared with group 1. Superoxide dismutase activity was similar in all the four groups. Malondialdehyde, chemiluminescence, and activity of catalase of aortic tissue decreased while activity of glutathione peroxidase increased in group 2. Atherosclerotic changes were lower in group 4 compared with group 3. Histologic changes were practically similar in groups 3 and 4. CONCLUSIONS: Increased levels of malondialdehyde, chemiluminescence, and antioxidant enzymes associated with development of atherosclerosis suggests a role for oxygen free radicals in the pathogenesis of hypercholesterolemic atherosclerosis. The protection afforded by garlic was associated with decrease in aortic malondialdehyde and chemiluminescence inspite of no change in serum cholesterol. These findings suggest that oxygen free radicals are involved in the genesis and maintenance of hypercholesterolemic atherosclerosis and that use of garlic can be useful in preventing the development of hypercholesterolemic atherosclerosis.     

Glycation of platelet protein in diabetes mellitus: lack of correlation with platelet function

The relationship of nonenzymatic glycation of platelet proteins to altered platelet function was studied in 33 diabetic patients. Platelets isolated from diabetic patients were glycated to a greater extent than those isolated from nondiabetic controls. No relationship was found between the level of glycation of platelets in diabetics to parameters commonly used to monitor glycemic control (glycated hemoglobin, glycated albumin, fasting blood glucose). Platelets isolated from diabetics did not show an increased level of aggregation and Thromboxane B2 production as compared to nondiabetic controls. No significant relationship was found between the level of glycation and percent aggregation of platelets. The lack of a relationship between glycation and aggregation suggests that the former may not be responsible for the functional changes in platelets seen in diabetics.     

Clinofibrate therapy raises high-density lipoprotein levels and lowers atherogenic index in diabetes mellitus patients

The effects of clinofibrate on serum lipoprotein concentrations, lecithin cholesterol acyl transferase activity and atherogenic index were studied in 10 diabetes mellitus patients. The patients comprised five with well-controlled non-insulin-dependent diabetes, and five with poorly controlled insulin-dependent diabetes; six non-insulin-dependent diabetics acted as placebo controls. No adverse side-effects were reported and there were no significant changes in total cholesterol, triglyceride or high-density lipoprotein 3-cholesterol concentrations following 600 mg/kg clinofibrate treatment for 4 weeks in either insulin-dependent or non-insulin-dependent diabetics. High-density lipoprotein-cholesterol concentrations and lecithin cholesterol acyl transferase activity were significantly (P less than 0.05) increased by clinofibrate treatment in insulin-dependent and non-insulin-dependent diabetics and high-density lipoprotein 2-cholesterol concentrations were significantly (P less than 0.05) increased by clinofibrate in insulin-dependent diabetics. The atherogenic index was significantly (P less than 0.01) reduced in non-insulin-dependent diabetics. It is suggested that the enhanced plasma lecithin cholesterol acyl transferase activity following clinofibrate therapy is the result of increased high-density lipoprotein-cholesterol and high-density lipoprotein 2-cholesterol concentrations and may play a central role in the efficacy of clinofibrate.     

Urinary excretion of glycated protein determined with a specific radioimmunoassay

We developed a simple and highly sensitive RIA for glycated protein (GP), and used it to measure GP in serum and urine from 15 normal controls and 30 diabetics (14 with urinary excretion rate of albumin, Ualb less than 15 micrograms/min, group A; nine with 15 less than or equal to Ualb less than or equal to 150 micrograms/min, group B; and seven with Ualb greater than 150 micrograms/min, group C). The mean serum concentration of GP was above normal in all groups of diabetics, and the mean glycation ratios of serum protein (SGP) were higher in groups B and C than in normal subjects. Urinary concentrations of GP also were increased in groups B and C, although the glycation ratio of urinary protein (UGP) was decreased in group C. Consequently, the selectivity of urinary excretion of GP (UGP/SGP) was significantly decreased in group C. Moreover, there was a significant difference in the mean values of selectivity between groups of patients with various degrees of retinopathy. We suggest that measurements of serum and urinary GP are useful to evaluate the progression of diabetic complications.     

Epigallocatechin gallate improves serum lipid profile and erythrocyte and cardiac tissue antioxidant parameters in Wistar rats fed an atherogenic diet

Oxidative stress is believed to contribute to the pathogenesis of hypercholesterolaemic atherosclerosis; hence, various antioxidant compounds are being evaluated for potential anti-atherogenic effects. The present study assessed the efficacy of epigallocatechin gallate (EGCG), an antioxidant component of the plant Camellia sinensis , in improving serum lipid profile and antioxidant parameters in erythrocytes and cardiac tissue in rats fed an atherogenic diet. In male albino Wistar rats fed an atherogenic diet for 30 days, significantly increased serum levels of total cholesterol, triglycerides and lipoprotein cholesterol fractions and cardiac risk ratio were noted, compared with levels in rats fed a normal diet. Intraperitoneal administration of EGCG (100 mg/kg) for 7 or 15 days to the atherogenic diet-fed rats resulted in significantly lower serum levels of total cholesterol, triglycerides, low-density and very low density lipoprotein cholesterol fractions and a significantly higher serum level of high-density lipoprotein cholesterol compared with levels in atherogenic diet-fed, saline-treated rats. Significantly higher mean malondialdehyde levels and significantly lower mean activities of antioxidant enzymes and mean levels of non-enzymatic antioxidants occurred in atherogenic diet-fed rats compared with those fed a normal diet. When atherogenic diet-fed rats received EGCG treatment for 7 or 15 days, significantly lower mean levels of MDA, higher mean levels of non-enzymatic antioxidants and higher mean activities of enzymatic antioxidants occurred, compared with those in saline-treated rats. Thus, EGCG appears to ameliorate disruptions of serum lipid profile and of antioxidant parameters in erythrocyte and cardiac tissue of Wistar rats fed an atherogenic diet; these results may be relevant to treating human atherosclerosis.     

Lipids and apolipoproteins in patients treated with major tranquilizers

The concentrations of lipids and apolipoproteins in serum from men with chronic schizophrenia who were receiving major tranquilizers (17 receiving phenothiazines and 14 receiving a butyrophenone) were quantitated and compared with serum from male controls (n = 14). Concentrations of high-density lipoprotein cholesterol and apolipoproteins A-I and A-II were significantly lower in the patients than in the controls. Mean apolipoproteins C-II and C-III and very low-density lipoprotein cholesterol levels in the patients receiving phenothiazines were higher than levels in the patients receiving butyrophenone or in the controls. There were no significant differences in levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or apolipoproteins B and E. The triglyceride level in patients receiving phenothiazines (163 +/- 65 mg/dl) was higher than that in patients receiving butyrophenone (104 +/- 52 mg/dl). Our data suggest that, with respect to triglyceride metabolism, butyrophenone is more beneficial than are phenothiazines.     

Long-term Treatment With Pravastatin Alone and in Combination With Gemfibrozil in Familial Type IIB Hyperlipoproteinemia or Combined Hyperlipidemia

BACKGROUND: Pravastatin inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase. It prevents mevalonate synthesis, reducing endogenous cholesterol production, and reduces cholesterol content in the liver, thus resulting in a down-regulation of low-density lipoprotein receptor production. Gemfibrozil reduces very low-density lipoprotein production and low-density lipoprotein-cholesterol level and increases very low-density lipoprotein catabolism. Therefore, it was suggested that combination therapy with both drugs could effect greater reduction of cholesterol levels as compared to pravastatin alone. The present study was carried out to evaluate the efficacy and safety of pravastatin as a monotherapy or in combination with gemfibrozil in the treatment of patients with familial type IIb hyperlipoproteinemia or familial combined hyperlipidemia. METHODS AND RESULTS: Forty-one patients were included in the study. All patients initially followed 6 weeks of hypolipidemic diet; subsequently they were randomized and received either 20 mg once daily of pravastatin alone (n = 13) or 20 mg of pravastatin together with 600 mg of gemfibrozil twice daily (n = 14). As a control, 14 patients were treated with diet only. The treatment lasted 24 months and clinical evaluation and laboratory tests were done at given time points. Both groups of treated patients showed an early reduction (3 months) of total (about 30% P <.01 vs controls), low-density lipoprotein (about 35%, P <.01 vs controls) and very low-density lipoprotein cholesterol levels (about 18%, P = NS). In contrast, high-density lipoprotein cholesterol levels increased significantly in patients treated with pravastatin and gemfibrozil (about 20%, P <.05 vs controls). Pravastatin treatment alone reduced the level of serum triglycerides as efficiently as in combination with gemfibrozil. Data showed a sustained normalization of lipid profile until 24 months. However, this effect was achieved in patients that had rather low levels of triglycerides. During the treatment we did not observe any difference in the incidence of possible drug-related side effects. Severe myopathy or rhabdomyolysis was not observed at the doses of the drugs used in our study. CONCLUSIONS: Therapy with pravastatin and in combination with gemfibrozil resulted in significant and sustained normalization of lipid profile in high-risk patients with familial type IIb hyperlipoproteinemia or familial combined hyperlipidemia.     

Nonenzymic glycation of apolipoprotein B in patients with insulin- and noninsulin-dependent diabetes mellitus

Objective: To evaluate the level of nonenzymatic glycation of apolipoprotein B in patients with insulin and noninsulin dependent diabetes mellitus.

Methods: Using a method based on a combination of affinity chromatography and immunonephelometry, we measured the concentration of glycated apolipoprotein B (apo B) in serum of 140 diabetic patients, 43 insulin-dependent (IDDM), and 97 noninsulin-dependent (NIDDM), and 45 nondiabetic control subjects.

Results: Although total apo B concentration in serum was significantly increased only in NIDDM patients, both groups of diabetics showed higher percentages of glycated apo B (IDDM, 4.84 ± 0.8%; NIDDM, 5.61 ± 1.1%) than did control subjects (4.28 ± 1.0%), the greatest percentage (5.80%) being found in patients with diabetic nephropathy. No significant correlations were found between glycated apo B and the traditional parameters of glycemic control, such as glycated hemoglobin and fructosamines, and direct influence by sudden plasma glucose fluctuations on apo B glycation was not shown either, perhaps for a low inherent glycability of this apolipoprotein.

Conclusions: It is unclear if these low proportions of glycated apo B in vivo may significantly affect lipoprotein metabolism assuming a pathophysiological role in atherogenesis.     

Lipid and lipoprotein profile in physiological pregnancy

Physiologic pregnancy is associated with a broad series of metabolic adaptations which may also influence the metabolism of lipids and lipoproteins. Although the modification of serum lipids and lipoproteins has been exhaustively investigated during and after pregnancy, the relative changes recorded vary widely among the different studies. A comprehensive lipid and lipoprotein profile was evaluated in 57 women with uncomplicated pregnancies at different gestational ages (20 in the first, 20 in the second, and 17 in the third trimester of pregnancy) and compared to that of 21 non-pregnant women. Conventional lipid parameters, including total cholesterol, high-density lipoprotein cholesterol and triglycerides, were evaluated on the Modular System P. Low-density lipoprotein cholesterol was quantified by the formula of Friedewald, the atherogenic index of plasma was quantified by the formula log (triglycerides/high-density lipoprotein cholesterol), whereas lipoprotein(a) was assayed on the BN II nephelometric analyzer. We observed that all the lipid parameters tested were significantly modified by the gestational age; in particular, women in the second and third trimester displayed significantly increased total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total to high-density lipoprotein cholesterol ratio, lipoprotein(a) and atherogenic index of plasma (third trimester only) when compared to either the control population or the subgroup of women in the first trimester of pregnancy. The value distributions and the relative percentage of women with undesirable or abnormal values according to the current NCEP or AHA/ACC goals were comparable between controls and women in the first trimester. However, when compared with either controls or women in the first trimester, advanced pregnancy was associated with an increased prevalence of undesirable or abnormal values for total cholesterol, low-density lipoprotein cholesterol and triglycerides in the second trimester, and total cholesterol, low-density lipoprotein cholesterol, triglycerides, total to high-density lipoprotein cholesterol ratio and lipoprotein(a) (only from non-pregnant women) in the third trimester. The results of this case-control study demonstrate that physiological pregnancy is associated with a substantial modification of the lipid and lipoprotein metabolism from the second trimester, providing reference ranges for traditional and emerging cardiovascular risk predictors throughout the gestational period.     

Apolipoprotein E polymorphisms in Mexican patients with coronary artery disease.

BACKGROUND: Apolipoprotein E polymorphisms have important effects on plasma lipid levels and in the genetic susceptibility to development of cardiovascular diseases. Thus, the purpose of this study was to investigate the association of apolipoprotein E polymorphisms with coronary artery disease and with plasma lipid levels in a group of Mexican Mestizo patients. METHODS: Apolipoprotein E polymorphisms were determined in 156 Mexican patients with coronary artery disease and 200 non-related healthy controls using the restriction fragment length polymorphism technique. The correlation of these polymorphisms with lipid profile (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides) in the patient group was determined. RESULTS: A similar distribution of allele and genotype frequencies in coronary artery disease patients and healthy controls was found. Higher serum levels of high-density lipoprotein cholesterol and lower levels of low-density lipoprotein cholesterol, triglycerides and glucose were found in patients with the APOE*2/3 genotype when compared to patients with the APOE*3/4 and APOE*3/3 genotypes, although these differences were not significant. CONCLUSIONS: Our data suggest that genetic variation at the APOE is not a genetic factor related to the genetic susceptibility to coronary artery disease in Mexican individuals, but the role of this polymorphism in determining the lipid profile cannot be excluded.     

Lack of effect of hepatic enzyme induction on metabolic control in patients with type 2 (non-insulin-dependent) diabetes

A placebo-controlled, double-blind crossover study was carried out in 11 non-insulin-dependent (type 2) diabetic patients to find out the effects of a hepatic enzyme inducer (phenobarbital, 100 mg/day for 2 months) on the metabolic control, plasma C-peptide, insulin, serum, and lipoprotein lipid levels. Phenobarbital induced a significant increase in hepatic antipyrine metabolizing activity, but no significant changes were found in fasting or postload blood glucose, plasma C-peptide, or insulin levels during the study. There was a significant increase in serum total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, as well as in serum total and very low-density lipoprotein triglycerides, during phenobarbital treatment as compared with placebo.     

Is high concentration of serum lipids a risk factor for Achilles tendon rupture?

BACKGROUND: The incidence of the Achilles tendon ruptures (ATR) seems to be increasing due to changes in life style and intensified sports activities in recent years. Intrinsic and extrinsic factors have been implicated as predisposing risk factors to rupture. The purpose of this study was to investigate whether the high serum lipid concentrations could be an intrinsic factor in patient with complete ruptures of Achilles tendon. METHODS: The data were collected from the records of 47 patients with complete rupture of Achilles and the control group consisted of 26 subjects. RESULTS: Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations of the patients with ATR were higher (p<0.001), and their high-density lipoprotein cholesterol (HDL-C) was lower than the control group (p<0.05). Moreover, the concentrations of triglyceride (TG) and very low-density lipoprotein cholesterol (VLDL-C) were significantly higher than controls (p<0.05). CONCLUSIONS: The causes of ATR are multifactorial and still unclear. However, high serum lipid concentrations might be considered, as a predisposing factor in patients with complete rupture of Achilles tendon and further investigations with larger groups would be better.     

Association in vivo of glycated apolipoprotein A-I with high density lipoproteins.

In diabetic patients, hyperglycaemia results in the non-enzymatic glycation of apolipoprotein A-I, the major protein of human high density lipoproteins. The effect of the non-enzymatic glycation on the association of apolipoprotein A-I with high density lipoprotein in vivo has been studied in the rat. The distribution volume obtained after injection of glycated apolipoprotein A-I was 2- to 3-fold higher in kidneys and approximately 30% lower in adrenals and ovaries than that obtained with apolipoprotein A-I. Analysis by gel chromatography of serum from donor rats shows that glycation diminishes the interaction between apolipoprotein A-I and high density lipoprotein. The findings in this study suggest that non-enzymatic glycation of apolipoprotein A-I may contribute to the development of atherosclerosis in patients with diabetes mellitus.     

Paraoxonase-1 (PON-1) genotype and activity and in vivo oxidized plasma low-density lipoprotein in Type II diabetes

The HDL (high-density lipoprotein)-associated enzyme PON (paraoxonase)-1 protects LDL (low-density lipoprotein) from oxidative modification in vitro, although it is unknown if this anti-atherogenic action occurs in vivo. In a cross-sectional study of 58 Type II diabetic subjects and 50 controls, we examined the fasting plasma LDL basal conjugated diene concentration [a direct measurement of circulating oxLDL (oxidatively modified LDL)], lipoprotein particle size by NMR spectroscopy, PON-1 polymorphisms (coding region polymorphisms Q192R and L55M, and gene promoter polymorphisms -108C/T and -162G/A), PON activity (with paraoxon or phenyl acetate as the substrates) and dietary antioxidant intake. Plasma oxLDL concentrations were higher in Type II diabetic patients (males, P = 0.048; females, P = 0.009) and unrelated to NMR lipoprotein size, PON-1 polymorphisms or PON activity (with paraoxon as the substrate) in any group. In men with Type II diabetes, however, there was a direct relationship between oxLDL concentrations and PON activity (with phenyl acetate as the substrate; r = 0.611, P = 0.0001) and an atherogenic NMR lipid profile in those who were PON-1 55LL homozygotes. Circulating oxLDL concentrations in vivo were unrelated to PON-1 genotypes or activity, except in male Type II diabetics where there was a direct association between PON activity (with phenyl acetate as the substrate) and oxLDL levels. These in vivo data contrast with in vitro data, and may be due to confounding by dietary fat intake. Male Type II diabetic subjects with PON-1 55LL homozygosity have an atherogenic NMR lipid profile independent of LDL oxidation. These data do not support an in vivo action of PON on LDL oxidation.     

Effect of glycation of low-density lipoprotein on the immunological determination of apolipoprotein B

Non-enzymatic glycation of low-density lipoprotein (LDL) may contribute to the premature atherogenesis of patients with diabetes mellitus. To assess whether glycation of apolipoprotein B, the predominant protein of LDL, interferes with the ability to immunologically quantify this protein, we prepared and purified glycated LDL by incubating normal plasma samples with high concentrations of glucose. Although both the plasma and the LDL specimens incubated with glucose contained significantly more glycated protein than control specimens, the quantitative interaction of an apolipoprotein B-specific antibody with glycated vs nonglycated LDL was not significantly different. We conclude that apolipoprotein B can be accurately quantified immunologically despite the presence of clinically excessive degrees of LDL glycation.     

Comparison of N-acetyl-beta-glucosaminidase and albuminuria with clinical finding of microangiopathy in type I diabetes mellitus

N-acetyl-beta-Glucosaminidase activity in serum and urine and microalbuminuria were measured in 70 type-I diabetics and compared with glycated serum protein as well as with the finding of diabetic retinopathy. A significantly increased N-acetyl-beta-glucosaminidase activity in serum correlated positively with glycated protein but not with the development of retinopathy. Urinary N-acetyl-beta-glucosaminidase activity and albuminuria were significantly increased in diabetics with (p less than 0.001) or without (p less than 0.01) retinopathy as compared to healthy controls. A significant positive correlation was observed between urinary N-acetyl-beta-glucosaminidase activity and albuminuria (r = 0.73, p less than 0.01) as well as between blood pressure and albuminuria (r = 0.51, p less than 0.05).     

Serum lipoprotein profile in patients with cancer. A comparison with non-cancer subjects

The association of cancer with low serum total cholesterol is well established. Less clear is the relationship of cancer with the cholesterol distribution among the different lipoprotein classes. Conflicting results have been reported on low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and serum triglyceride levels in different types of tumor. Total serum cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and serum triglycerides were analyzed in 530 patients with newly diagnosed cancer (97 with hematological malignancies, 92 with tumor of the lung, 108 of the upper digestive system, 103 of colon, 32 of breast, and 98 of the genitourinary system) and in 415 non-cancer subjects. Anthropometric (body mass index) and biochemical (serum albumin) indices of nutritional status were also determined in all subjects. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum albumin, and body mass index were significantly lower in cancer than in non cancer-subjects. The lowest values of total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol were recorded in patients with hematological malignancies and the highest in patients with breast tumor. All the cancer groups, with the exception of women with breast cancer, showed significantly lower total cholesterol, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol than age- and sex-matched non-cancer subjects. Multiple regression analysis with low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides as dependent variables and sex, age, body mass index, albumin, and cancer (dummy variable) as independent variables, showed that cancer was independently associated with low levels of low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol and with high values of serum triglycerides. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, serum triglycerides, body mass index and serum albumin were significantly lower in patients with metastatic than in patients with non-metastatic solid tumor. The significant difference in low-density lipoprotein-cholesterol and serum triglycerides between patients with metastatic and non-metastatic cancer was lost when lipoprotein cholesterol and serum triglyceride levels were adjusted for nutritional variables. The lipid profile in cancer patients is characterized by low low-density lipoprotein-cholesterol, low high-density lipoprotein-cholesterol and relatively high serum triglycerides. The abnormality is a common feature of both hematological and solid tumors and is not entirely explained by poor nutrition.