Carl Bryngelsson

Enhanced DNA repair, immune function and reduced toxicity of C-MED-100, a novel aqueous extract from Uncaria tomentosa

Female W/Fu rats were gavaged daily with a water-soluble extract (C-MED-100) of Uncaria tomentosa supplied commercially by CampaMed at the doses of 0, 5, 10, 20, 40 and 80 mg/kg for 8 consecutive weeks. Phytohemagglutinin (PHA) stimulated lymphocyte proliferation was significantly increased in splenocytes of rats treated at the doses of 40 and 80 mg/kg. White blood cells (WBC) from the C-MED-100 treatment groups of 40 and 80 mg/kg for 8 weeks or 160 mg/kg for 4 weeks were significantly elevated compared with controls (P < 0.05). In a human volunteer study, C-MED-100 was given daily at 5 mg/kg for 6 consecutive weeks to four healthy adult males. No toxicity was observed and again, WBC were significantly elevated (P < 0.05) after supplement. Repair of DNA single strand breaks (SSB) and double strand breaks (DSB) 3 h after 12 Gy whole body irradiation of rats were also significantly improved in C-MED-100 treated animals (P < 0.05). The LD50 and MTD of a single oral dose of C-MED-100 in the rat were observed to be greater than 8 g/kg. Although the rats were treated daily with U. tomentosa extracts at the doses of 10-80 mg/kg for 8 weeks or 160 mg/kg for 4 weeks, no acute or chronic toxicity signs were observed symptomatically. In addition, no body weight, food consumption, organ weight and kidney, liver, spleen, and heart pathological changes were found to be associated with C-MED-100 treatment.

Interindividual variation in the responses of cultured human lymphocytes to exposure from DNA damaging chemical agents: Interindividual variation to carcinogen exposure

Human population variability to standardized doses of N-acetoxy-2-acetylaminofluorene (NA-AAF) and 7, 12-dimethylbenz(a) anthracene (DMBA) was determined in cultured lymphocytes by measuring (a) differential stimulation of unscheduled DNA synthesis after 1 h induction of DNA damage by 10 micrometer NA-AAF, (b) the level of NA-AAF induced chromosome aberrations remaining after 8 h of DNA-repair synthesis, and (c) the level of [3H]DMBA bound to DNA after 18 h incubation of resting lymphocytes in 5 micrometer DMBA. All 3 parameters indicated individual variation to carcinogen exposure and were correlated to the population differences in age, sex, blood pressure and mortality rates. Males always had a greater potential to accumulate DNA-damage than did females regardless of the sampled population. DNA-damage potentials increased with increasing age, blood pressure or mortality rates. There was always proportionally greater DNA-damage potentials in the males than in females. The in vitro response of mature granulocytes to a 10 micrometer NA-AAF dose, as estimated by [3H] thymidine incorporation from unscheduled DNA synthesis, was much lower than lymphocyte response. Nevertheless, individual variations in granulocyte NA-AAF induced unscheduled DNA synthesis paralleled the inter-individual fluctuations observed in the lymphocyte responses to NA-AAF.

A genetic component of the variance of N-acetoxy-2-acetylaminofluorene-induced DNA damage in mononuclear leukocytes determined by a twin study.

SummaryThe level of N-acetoxy-2-acetylaminofluorene (NA-AAF)-induced unscheduled DNA synthesis and the level of covalent binding of NA-AAF to DNA were determined in the mononuclear leukocytes of monozygotic and diazygotic twin pairs (n=16 for each type). A statistically significant high degree of heritability was calculated for both parameters which, in turn, indicate genetic control of individual levels of induced DNA damage by NA-AAF.

Mutagen sensitivity, smoking habits and enzyme induction in healthy middle-aged men

Unscheduled DNA synthesis (UDS) (excision-repair) of N-acetoxy-2-acetylaminofluorene (NA-AAF) damage to the DNA of human lymphocytes and levels of 3H-labeled NA-AAF bound to the DNA (carcinogen binding) of lymphocytes after 18 hr of culturing were measured in a consecutive subsample of healthy middle-aged males attending a multiphasic health screening program at the Department of Preventive Medicine in Malmö during 3 weeks in November-December 1981, and compared relative to their smoking habits, body weight, serum cholesterol, and gamma-glutamyltransferase levels as well as aryl hydrocarbon hydroxylase inducibility. This study group numbered 66 males and was uniform in sex, age, and investigation time. No case of significant arterial hypertension was present. The UDS and carcinogen binding results showed no correlation with the other factors measured, with the exception of smoking which was strongly (P less than 0.01) associated with increasing levels of both the UDS and carcinogen binding values. It is concluded that under ordinary circumstances smoking may represent the most important exogenous factor which may modulate risk to cardiovascular disease and cancer by influencing individual mutagen sensitivity.

The effects of smoking, hypertension and cardiovascular disease on the estimation of unscheduled DNA synthesis and covalent binding to DNA induced by N-acetoxy-2-acetylaminofluorene in resting human mononuclear leukocytes.

The levels of N-acetoxy-2-acetylaminofluorene (NA-AAF)-induced unscheduled DNA synthesis (UDS) and of NA-AAF binding to DNA have been determined in resting mononuclear leukocytes from individuals with various smoking habits, heart infarct patients and subjects diagnosed for hypertension. Age-matched and blood-pressure-controlled smokers (n = 99) had significantly elevated levels of NA-AAF-induced UDS and NA-AAF binding to DNA when compared to nonsmokers (n = 75) similarly corrected for age and blood pressure. Heart infarct patients without any history of risk factors, as well as diagnosed hypertensives with normalized blood pressure, were not significantly different from matched controls when assessed by the NA-AAF method. Our results support the theory that increased mutagen sensitivity is associated with smoking and high blood pressure but not with cardiovascular disease itself via some mechanism of genetic selection.

The effect of an individual's blood pressure on the percentage of total 7,12-dimethylbenz[a]anthracene metabolites that bind covalently to DNA in cultured resting lymphocytes

A method for the quantitative analysis of the percent metabolism that results in covalent binding of 7,12-dimethylbenz[a]anthracene (DMBA) to DNA in viable resting human lymphocytes is described. The inter- and intra-experimental reproducibility as judged by the coefficient of variation and examined in the same individual over a 3-month period was 31.4% and 13.9%, respectively. When the lymphocytes from 30 hypertensive individuals were exposed to 1 microM DMBA for 18 h, the percent of total DMBA metabolites that bind DNA covalently was correlated to the blood pressures of the patients at the time of sampling (r = 0.53, P less than 0.005). No influences on the data from the type or duration of hypertensive drug treatment could be statistically determined for this sample of hypertensive patients. It was concluded that high blood pressure is a strong determinant in predisposing lymphocytes to increased genetic risk from induced DNA damage and that this relationship is not statistically affected by hypertensive drug therapy.

Carcinogen-induced repair and binding in the DNA of chronic lymphocytic leukemic lymphocytes

Unscheduled DNA synthesis (repair) of carcinogen induced damage of the DNA of lymphocytes from 16 normal and 16 chronic lymphocytic leukemic (CLL) subjects was determined quantitatively for a standard dose of 10 micronM N-acetoxy-2-acetylaminofluorene (NA-AAF). Essentially all the CLL cases (15 of 16) had lower NA-AAF induced repair synthesis values than the normal subjects. Concurrent measurements for the levels of 3H-labeled 7,12-dimethyl-benz(a)anthracene (DMBA) to the DNAs of the normal and CLL lymphocytes after 18 h of culturing in 5 micronM DMBA have shown that 14 of 16 CLL cases had reduced levels of DNA bound carcinogen when compared to the normal individuals. Together these results suggest that CLL lymphocytes have a reduced repair synthesis because there is disproportionately less initial carcinogen-induced damage, and thereby, less substrate stimulation of repair enzymatic activity.