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PubMed1994

Glycation of albumin: reaction with glucose, fructose, galactose, ribose or glyceraldehyde measured using four methods.

Albumin was glycated (nonenzymatically glycosylated) with glucose, fructose, galactose, ribose or glyceraldehyde for 5, 9, 15 and 19 days. The extent of glycation was determined (a) by the thiobarbituric acid method, (b) by fructosamine assay, (c) by method based on the reaction with hydrazine, and (d) by measurement of fluorescence. Results show that the three colorimetric methods used differ in the sensitivity and in addition with the use of each method not the same extent of glycation with various sugars was found.

Albumins↗

PubMed1990

Plasma thrombomodulin concentration in diabetes mellitus.

Thrombomodulin is an endothelial cell membrane protein acting as a cofactor for the activation of plasma protein C. Recently, it was found that soluble forms of thrombomodulin exist in plasma. Although the physiological significance of circulating thrombomodulin is presently obscure, it may reflect injury of the endothelial cell. In the present study, we examined plasma thrombomodulin concentrations in 106 Type 2 (non-insulin-dependent) diabetic patients. Plasma thrombomodulin was determined by a sandwich ELISA employing monoclonal anti-thrombomodulin antibodies. The patients with proteinuria had higher plasma thrombomodulin concentrations (61.0 +/- 36.0 ng/ml) compared to the patients without proteinuria (33.6 +/- 9.5 ng/ml, P less than 0.001) and control subjects (32.8 +/- 6.5 ng/ml, P less than 0.001). Plasma thrombomodulin concentrations were positively correlated with the level of serum creatine, blood urea nitrogen, urinary albumin and urinary beta 2-microglobulin (P less than 0.001 for each), but not with fasting plasma glucose, hemoglobin A1c or fructosamine. Elevated plasma thrombomodulin was also observed in the patients with pre-proliferative (63.4 +/- 28.9 ng/ml) or proliferative retinopathy (57.4 +/- 34.7 ng/ml), but not in the patients with non-proliferative retinopathy (33.5 +/- 12.9 ng/ml) or those without retinopathy (32.4 +/- 8.9 ng/ml). Even in the 81 diabetic subjects without proteinuria as determined by a dip and read method, and whose serum creatinine was lower than 1.0 mg/dl, the plasma thrombomodulin concentration was significantly higher in the patients with pre-proliferative (41.5 +/- 4.4 ng/ml) and proliferative retinopathy (41.0 +/- 12.8 ng/ml) compared to the patients without retinopathy (32.2 +/- 8.8 ng/ml) and those with non-proliferative retinopathy (31.9 +/- 7.8 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗

PubMedDate not supplied

Raised liver associated enzyme activity and post-prandial bile acid concentrations in sera from treated diabetic outpatients.

Aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transferase activities were measured in sera from 411 diabetic outpatients and were raised in 26 (6.4%), 34 (8.3%) and 62 (15.2%) patients, respectively. Serum total bile acid concentrations were raised in 4 patients (1%). Percentage glycated hemoglobin A1, serum fructosamine concentration and plasma glucose concentration were also measured. No relationship between the presence of raised enzyme activity and mature age, short duration of diabetic treatment regimen or glycemic control was found. Twenty-six patients with an alanine aminotransferase activity greater than 60 U/l were reviewed at 23 +/- 6.5 weeks. The activity of this enzyme had fallen to within the reference interval in 15 (58%). In the other 11 patients, its median activity was 75 U/l (range 51-181 U/l). Median gamma-glutamyl transferase activity had risen in these 11 patients from 78 U/l to 93 U/l (P less than 0.01). No statistical differences in treatment regimen or glycemic control were found between these two groups. Raised liver-associated enzyme activity in treated stabilised diabetic outpatients should therefore not be attributed to poor glycemic control or diabetic treatment regimen.

Alanine Transaminase↗

PubMed1994

Serum 1,5-anhydroglucitol (1,5 AG): new clinical marker for glycemic control.

We review the use of 1,5-anhydroglucitol (1,5 AG) in diagnosing and monitoring patients with diabetes. This six-carbon chain monosaccharide is one of the major polyols present in humans. Its concentration in serum is normally about 12 to 40 micrograms/ml. This substance is derived mainly from food, is well absorbed in the intestine, and is distributed to all organs and tissues. It is metabolically stable, being excreted in the urine when its level exceeds the renal threshold. It is reabsorbed in the renal tubules, and is competitively inhibited by glucosuria, which leads to a reduction in its level in serum. The correlation between this reduction and the amount of glucose present in urine is so close that 1,5 AG can be used as a sensitive, day-to-day, real-time marker of glycemic control. It provides useful information on current glycemic control and is superior to both HbA1c and fructosamine in detecting near-normoglycemia.

Biomarkers↗

PubMed1996

Clinical significance of measurements of urinary and serum thrombomodulins in patients with non-insulin-dependent diabetes mellitus.

UNLABELLED: The aim of our study was to elucidate whether serum thrombomodulin (S-TM) and urinary thrombomodulin (U-TM) levels would reflect the pathogenesis of diabetic complications. Studies were conducted in 188 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 132 age-matched healthy subjects. TM was measured by a newly developed enzyme immunoassay. Both S-TM and U-TM levels in NIDDM were much higher than those in healthy controls. S-TM values in NIDDM correlated significantly with age (P < 0.05), HbA1c (P < 0.05), serum 1.5 anhydroglucetol (AG) (P < 0.05) and urinary albumin concentration (UAC) (P < 0.01), respectively. On the other hand, fasting plasma glucose (FPG) (P < 0.001), HbA1c (P < 0 .01), serum fructosamine (P < 0.05) and serum 1.5 AG (P < 0.05) were closely correlated with U-TM values in NIDDM. Patients with clinical nephropathy showed obviously higher S-TM levels (P < 0.05) than patients with latent nephropathy. Furthermore, S-TM values in patients with diabetic proliferative retinopathy increased significantly compared with those in patients without diabetic retinopathy (P < 0.05). When all diabetic patients with normoalbuminuria were studied, no significant changes of S-TM were observed between the no diabetic retinopathy group and the proliferative diabetic retinopathy group. CONCLUSIONS: The present data suggest that an increase in U-TM reflects the grade of glucose metabolism, whereas an increase in S-TM appears to reveal the advance of diabetic microangiopathy, including nephropathy.

Adult↗

PubMed1978

Distribution of adenosine 5'-triphosphate (ATP)-dependent hexose kinases in microorganisms.

A systematic study of adenosine triphosphate (ATP)-dependent hexose kinases among microorganisms has been undertaken. Sixteen hexose kinases of five major types were partially purified from 12 microorganisms and characterized with respect to specificity for sugar and nucleotide substrates and Michaelis constants for the sugar substrates. Glucokinase activities that phosphorylate glucose and glucosamine are inhibited by N-acetyl-glucosamine and xylose, were found to be present in the non-sulphur photosynthetic bacteria Rhodospirillum rubrum, the blue-green algae Anacystis montana, and the protists Chlorella pyrenoidosa and Chlamydomonas reinhardtii (green algae), Hypochytrium catenoides (Hypochytridiomycete) and Saprolegnia Iitoralis (Oomycete). The myxobacteria Stigmatella aurantiaca contains a glucokinase activity with a different specificity pattern. Anacystis and Chlorella, besides their glucokinase activities, contain highly specific fructokinases, although that from Anacystis can also phosphorylate fructosamine; fructokinase from Anacystis has a molecular weight of 20 000, and exhibits a sigmoidal saturation curve for ATP when the Mg2+/ATP ratio is 2; this curve is transformed to a Michaelian one when under the same conditions an excess of Mg2+ (5 mM) is added. Saprolegnia however, besides the glucokinase, contains a mannofructokinase activity that phosphorylates mannose (Km 0.06 mM) and fructose (1 mM). On the other hand, hexokinase, a low specificity enzyme, was detected in the protist Allomyces arbuscula (Chytridiomycete) and in fungi Mucor hiemalis and Phycomyces blakesleeanus (Zygomycetes), and Schizophyllum commune (Basidiomycete). Schizophyllum contains a glucomannokinase activity together with hexokinase activity. The pattern of distribution of ATP-dependent hexose kinases among microorganisms seems to parallel that reported for biosynthetic pathways for lysine. The correlation with other biochemical parameters is also considered.

Bacteria↗

PubMed1994

The effect of Rhazya stricta on glucose homeostasis in normal and streptozotocin diabetic rats.

The effect of R. stricta water extract on glucose homeostasis was studied in normal and streptozotocin diabetic rats. R. stricta had no effect on fasting glucose levels in normal and diabetic rats up to 7 h after its oral administration. In normal and diabetic rats R. stricta did not produce any significant effect on an oral glucose tolerance test (OGTT). Chronic administration of R. stricta in drinking water for 37 days did not produce any effect on the parameters of glucose homeostasis studied (plasma glucose, body weight, feed and fluid intake and plasma fructosamine) in the normal or diabetic phase of the experiment. The LD50 of R. stricta in mice was 2.36 g/kg body weight of the lyophilised extract and a daily administration of R. stricta to rats for 5 days did not produce any signs of organ damage.

Administration, Oral↗

PubMedDate not supplied

Studies of whole blood-associated acetaldehyde levels in teetotalers.

We measured whole blood-associated acetaldehyde (WBAA) levels in 225 teetotalers (123 females, 102 males) between the ages of 18 and 86 years. Values were normally distributed, but mean values for females were significantly lower than for males (7.6 +/- 0.6 vs. 7.9 +/- 0.7 microM, p < 0.0001). There was a significant positive correlation with age for the entire group (r2 = 0.149, p = 0.001) and for both sexes. The correlation with WBAA and age was stronger for females. Significant but lesser positive correlations were found between WBAA and other variables that increase with age, including glucose, fructosamine, cholesterol, alkaline phosphatase, serum glutamate pyruvate transaminase (SGPT), gamma glutamyl transpeptidase (GGT), and creatinine in the entire data set. Partial r analyses indicated that the correlations were mediated through the primary association of WBAA and age. We conclude that in individuals who do not consume ethanol there are significant sex differences in whole blood acetaldehyde and that the values increase throughout life.

Acetaldehyde↗

PubMedDate not supplied

Renal and glycemic determinants of glomerular hyperfiltration in normoalbuminuric diabetics.

Glomerular hyperfiltration is a characteristic feature of insulin-dependent diabetes. We examined the relative roles of renal size, as well as glycemic parameters (HbA1c, glycosylated albumin, plasma glucose) in addition to growth hormone, somatomedin C, beta-hydroxybutyrate, alanine, and glycerol in determining the glomerular filtration rate (GFR). Sixty-two insulin-dependent patients with normal urinary albumin excretion rates (AER less than 15 micrograms/min), who were less than 50 years of age, were included in the study. Data were subjected to multiple regression analysis with GFR as a dependent variable. Renal volume was the primary statistical determinant of hyperfiltration, but HbA1c also significantly correlated with GFR. No correlation was found with glycosylated albumin or blood glucose, but RPF correlated strongly with GFR, and borderline correlation was found between renal volume and HbA1c. Renal hyperfiltration, defined as a GFR greater than 150 ml/min, was found in approximately 50% of patients with HbA1c values greater than 9.5%. Other studies suggest that such patients have a much higher risk of developing clinically evident diabetic nephropathy over the ensuing years. Renal volume appears to be the major determinant of GFR, but long-term metabolic control, as evidenced by the level of HbA1c, also contributes, partly independent of renal volume. Short-term metabolic control, as evaluated by blood glucose and serum-fructosamine, did not correlate with GFR. We suggest that exact determination of GFR and renal volume should be included in long-term prospective controlled intervention trials in patients with insulin-dependent diabetes mellitus (IDDM).

Adolescent↗

PubMedDate not supplied

Effects of angiotensin-converting enzyme inhibitor (alacepril) and calcium antagonist (nicardipine) in hypertensive non-insulin-dependent diabetic patients with microalbuminuria.

The influence of alacepril (50 mg/day) on arterial blood pressure and microproteinuria in 26 hypertensive non-insulin-dependent diabetic patients was studied for 16 weeks. Alacepril reduced blood pressure gradually from 175/88 (standard error of mean [SEM] 2.6/1.7) to 152/81 (3.3/2.0) mm Hg (P less than .005) and albuminuria from 160.6 (SEM 29.1) to 98.1 (14.1) mg/g Cr (P less than .05), while serum blood urea nitrogen, creatinine, HbA1c, and fructosamine (FRA) remained stable. No significant changes occurred in the urinary beta 2 microglobulin and N-acetyl-beta-D-glucosaminidase levels. As compared with the effects of a calcium antagonist (nicardipine, 60 mg/day) that reduced blood pressure from 170/92 (SEM 2.5/1.4) to 154/84 (2.5/1.5) mm Hg (P less than .001) and albuminuria from 162.2 (SEM 33.9) to 95.4 (25.0) mg/g Cr (not significant), it is suggested that the angiotensin-converting enzyme inhibitor (alacepril) may have an advantageous renal effect in spite of its mild antihypertensive effect.

Acetylglucosaminidase↗

PubMed1995

Insulin versus glipizide treatment in patients with non-insulin-dependent diabetes mellitus. Effects on blood pressure and glucose tolerance.

Insulin resistance that exists in patients with essential hypertension and in those with non-insulin-dependent diabetes mellitus (NIDDM) may be the common denominator for the impaired glucose homeostasis and elevated blood pressure (BP) levels in patients with NIDDM. Therefore, treatment that improves insulin action may also improve BP levels. Consequently, a four-phase (glipizide v insulin) cross-over design study was conducted to determine a better effect of glipizide treatment on insulin sensitivity and the effect this has on BP in 19 NIDDM patients. Patients were subjected to 1 month of diet only (phase I) followed by 3 months of glipizide treatment (phase II), then an additional 1 month of diet only (phase III), and finally 3 months of insulin treatment (phase IV). At the end of phases I, II, and IV oral glucose tolerance tests (OGTT) were performed and plasma glucose, insulin, and C-peptide levels were analyzed. Fasting plasma glucose, insulin, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides, glycated hemoglobin, fructosamine, and 2-h postprandial plasma glucose were also analyzed at each phase. Supine and sitting BP levels and body weights were determined biweekly during the study. With the exception of higher plasma insulin and C-peptide levels during the OGTT (area under the curve) in phase IV (insulin) v phase II (glipizide) (both P < .05), and higher fasting plasma insulin levels (P < .06), there were no consistently significant metabolic differences between phases IV and II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Relationship of lipid peroxides to diabetic complications. Comparison with conventional laboratory tests.

One hundred and seventy-three Arab patients with non-insulin-dependent diabetes mellitus (NIDDM) and 51 controls were examined. The routine laboratory tests of fasting blood sugar (FBS), glycosylated hemoglobin (HbA1c), fructosamine (FRA), and triglycerides (TG) were compared with lipid hydroperoxides (LHP) as detected by the thiobarbituric acid (TBA) method, which measures total TBA reacting substances (TBARS). All routine laboratory measures were elevated in the patient population. In the case of LHP, values in NIDDM were 491 +/- 183 mumol/L for men and 507 +/- 183 mumol/L for women, as compared with pooled normal values of 275 +/- 85 mumol/L. Seven patients with NIDDM undergoing hemodialysis were also elevated above normal (441 +/- 97 mumol/L). Comparisons between LHP and the other biochemical parameters indicated a positive statistical correlation with triglycerides (p less than 0.001); FBS, HbA1c, and FRA (p greater than 0.01). Patients with NIDDM on dietary control had somewhat lower LHP levels (441 +/- 135 mumol/L) than those receiving insulin (519 +/- 206 mumol/L), or oral hypoglycemic agents (518 +/- 177 mumol/L). Dietary maintenance also resulted in reduced FBS and HbA1c levels. Subdivision of patients according to duration of disease and by nationality showed that Kuwaiti nationals had slightly higher LHP values than did patients of other Arabic origin. Women patients (Kuwaiti and non-Kuwaiti) with NIDDM disease duration of greater than 10 years, had LHP levels above those of males (551 +/- 245 versus 478 +/- 126 mumol/L) and, as a group, showed significant enhancement of retinal complications (85.5% versus 55%). A statistically significant trend (p less than 0.08) could be demonstrated between the prevalence of retinopathy and increasing serum LHP levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Audit of the change from twice daily to basal-bolus insulin regimens in insulin-dependent diabetes.

Basal-bolus insulin regimens have become popular with patients, but clinicians' enthusiasm for their use has been tempered by a number of reports that suggest that these regimens do not improve overall glycemic control when compared with conventional, twice daily, regimens. Indeed, it has been suggested that basal-bolus regimens may be abused by certain patients leading to an increase in body weight and deterioration in glycemic control. This paper reports the results of a retrospective audit of 145 insulin-dependent diabetic patients changed from conventional insulin therapy to a basal-bolus insulin regimen. After 3 months on the basal-bolus regimen, a small but significant fall in total insulin (10%; p < 0.001) and intermediate-acting insulin (50%; p < 0.001) dose was recorded. During this time period serum fructosamine measurements also fell by 10% (p < 0.001) indicating a small but significant improvement in glycemic control. Body-mass index (BMI) and body weight data did not support the view that basal-bolus regimens lead to an increase in body weight. Analysis of the data by gender did not support the view that the basal-bolus insulin regimen is prone to abuse by female patients.

Adolescent↗

PubMedDate not supplied

Renal handling of uric acid in patients with type 1 diabetes in relation to glycemic control.

BACKGROUND: The aim of the study was to compare the renal handling of uric acid (UA) in 16 patients with type 1 diabetes without renal failure (age 34.8 +/- 13.3 years) and in 15 healthy subjects (age 34.9 +/- 12.6 years). METHODS: Creatinine clearance (Cr-Cl), clearance of uric acid (UA-Cl), fractional excretion of uric acid (UA-FE), and 24-h urinary UA excretion (UA-U) were determined. Glycemic control was assessed using fasting glucose, glycated hemoglobin and fructosamine tests. RESULTS: Patients with diabetes had significantly (p < 0.0001) lower serum UA concentrations compared to control group (2.8 +/- 0.7 vs. 5.7 +/- 0.8 mg/dl), and higher urinary UA excretion (813 +/- 107 vs. 423 +/- 40 mg/day), UA clearance (21.9 +/- 7.1 vs. 5.2 +/- 0.9 mL/min) and fractional UA excretion (17.1 +/- 5.5 vs. 4.8 +/- 1.3%), with higher creatinine clearance (129 +/- 16 vs. 111 +/- 12 mL/min, p < 0.005). In patients with diabetes there was a strong negative correlation between serum UA concentration and UA 24-h excretion (R = -0.79; p < 0.001). Fractional UA excretion correlated with fasting glycemia and HbA1c (R = +0.51 and +0.53; p < 0.05). CONCLUSIONS: In type 1 diabetes there is significant UA renal clearance increase, which is higher with poor glycemic control. It leads to hypouricemia despite an approximately twofold UA excretion increase and therefore despite increased UA synthesis.

Adult↗

PubMed2006

Free radical scavenging, anti-glycation and tyrosinase inhibition properties of a polysaccharide fraction isolated from the rind from Punica granatum.

The present investigation deals with the isolation of a polysaccharide fraction from Pomegranate (PFP), which was found to inhibit 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azinobis[3-ethylbenzothiazoline-6-sulfonate] ABTS(+) radical activities by 69% and 88%, respectively with 4 microg/ml concentration. The activity of PFP for free radical scavenging was also evaluated by electron spin resonance (ESR) Spectrophotometer and DPPH dot blot test. Anti-glycation ability of PFP was tested using BSA, which inhibited the formation of advanced glycation end-products (AGEs) by 28% and also inhibited the formation of fructosamine in the BSA/Glucose system. The inhibition of mushroom tyrosinase by 43% at 10 microg/ml concentration of PFP strongly suggested its efficacy as a possible skin whitener.

Benzothiazoles↗

PubMed2006

The evaluation of altered redox status in plasma and mitochondria of acute and chronic diabetic rats.

OBJECTIVES: An increase in plasma oxidative stress and decreased mitochondrial lipid hydroperoxides may contribute to the imbalance in the redox status between intramitochondrial and extramitochondrial milieu in chronic experimental diabetic rats. DESIGN AND METHODS: To determine the effect of hyperglycemia in promoting redox imbalance, we determined lipid hydroperoxides (LHP), protein carbonyl (PCO), total antioxidant activity (ferric reducing/antioxidant power; FRAP) and albumin as markers of redox status of plasma, and mitochondrial lipid hydroperoxide levels as a marker of lipid peroxidation in liver, pancreas and kidney tissue of acute and chronic diabetic male Sprague-Dawley rats and their controls. The levels of the studied markers were determined by colorimetric methods. RESULTS: Plasma and mitochondrial oxidative stress parameter levels of acute diabetic rats were not significantly different from their controls. Plasma LHP and PCO levels of chronic diabetic rats were increased significantly as compared to those of both acute diabetic rats and the controls. Plasma FRAP levels of chronic diabetic animals were decreased significantly as compared to those of the controls. On the other hand, LHP levels in liver, pancreas and kidney mitochondria of chronic diabetic rats were decreased significantly as compared to those of both acute diabetic rats and the controls. We observed a negative correlation between LHP levels in liver mitochondria of chronic diabetic rats, and PCO and fructosamine levels in plasma of chronic diabetic rats were correlated. LHP levels in the pancreatic mitochondria of chronic diabetic rats and plasma oxidative stress parameters of chronic diabetic rats were not significantly correlated. LHP levels in kidney mitochondria of chronic diabetic rats were significantly correlated with serum albumin. There was no correlation between LHP levels in kidney mitochondria and other plasma oxidative stress parameters in chronic diabetic rats. CONCLUSIONS: Our data suggest that redox imbalance between plasma and liver mitochondria might become a major threat to chronic diabetic rats.

Animals↗

PubMed2006

Acromegaly due to a somatroph adenoma in a dog.

A 10-year-old uncastrated male Dalmatian dog was referred for gait abnormalities consisting of chronic progressive stiffness and rigidity. Other symptoms were polyphagia associated with weight gain, polyuria and polydipsia, excessive panting, and an inspiratory stridor. The owner had noticed progressive thickening of the skin and enlargement of the tongue over the last 3 years. Physical examination revealed thickening of the skin, redundant skin folds, and enlargement of the tongue. The only remarkable abnormalities found on routine laboratory examination were mild anaemia and an increased serum fructosamine concentration. Circulating concentrations of total thyroxine, free thyroxine, and cTSH, and the results of an ACTH stimulation test were all within reference ranges. The basal serum growth hormone (GH) concentration was markedly elevated (23microg/l) and did not decrease during a glucose tolerance test or after somatostatin administration. The serum insulin-like growth factor-1 concentration was also markedly elevated (1254microg/l). Basal serum insulin concentration was high (95mU/l) and insulin concentrations increased considerably after glucose loading, consistent with insulin resistance. Abdominal ultrasonography showed no abnormalities. Survey radiographs of the vertebral column showed severe spondylosis deformans extending from the cervical to the lumbosacral spine. CT scanning of the skull showed an enlarged pituitary gland with normal enhancement pattern. On post-mortem examination, the entire vertebral column appeared as a single and inflexible structure due to the presence of multiple fused osteophytes. The pituitary gland contained an acidophilic adenoma that immunostained positively for GH (and negatively for ACTH and alpha-MSH). In conclusion, this Dalmatian dog with acromegaly and insulin resistance represents the first case of GH hypersecretion proven to be due to a somatotroph adenoma.

Acromegaly↗

PubMed2004

Commonly consumed and naturally occurring dietary substances affect biomarkers of oxidative stress and DNA damage in healthy rats.

The influence of black currant juice, Bowman-Birk protease inhibitor (BBI), kolaviron (a biflavonoid fraction of Garcinia kola seed), sugars, vitamin C and tert-butyl hydroperoxide on a wide range of biomarkers for oxidative stress, DNA damage and sugar or lipid metabolism has been investigated in male F 344 rats. The selected pro-oxidant control, tert-butyl hydroperoxide, significantly increased plasma and liver 2-amino-adipic semialdehyde (AAS), a marker of protein oxidation (p <0.05) whereas lipid oxidation assessed as malon dialdehyde (MDA) and DNA oxidation were not significantly increased. Feeding BBI also increased the level of oxidized protein in plasma and liver at the higher dose level (0.5%). No effect was observed at the lower dose level (0.25%), which even decreased lipid oxidation in plasma. BBI did not affect background levels of DNA strand breaks or oxidation (comets). In rats exposed to black currant juice, a statistically significant decrease in liver AAS and MDA was observed. This effect could not be explained by its content of sugars or of the known redox active constituent, vitamin C. The lowering effect of black currant juice on protein and lipid oxidation was similar in magnitude to that of the known liver protectant, kolaviron. In rats treated with kolaviron (200 mg/kg body weight), background AAS levels were significantly reduced in both plasma and liver whereas the effect on MDA only reached statistical significance in plasma. Kolaviron was the only extract tested which decreased oxidative damage to DNA in the liver. The erythrocyte antioxidant enzyme activities, catalase and glutathione peroxidase were decreased in rats treated with tert-butyl hydroperoxide (p <0.05) but were not affected by the other treatments. Black currant juice and sugars increased plasma triglyceride levels and black currant juice increased plasma cholesterol but neither of them nor any other treatment affected blood glucose, erythrocyte HbA1c or fructosamine. We conclude that markers of oxidative stress may be modified by several mechanisms after feeding rats with complex dietary factors and that both pro- and antioxidant effects may consequently be observed simultaneously after short-term feeding of antioxidant-rich foods, herb medicines, or known pro- and antioxidants.

Animals↗