Fruit and Vegetable Intake and Non-Communicable Diseases among Adults Aged ≥50 Years in Low- and Middle-Income Countries.

OBJECTIVES: The relationship between consuming ≥2 servings of fruits and ≥3 servings of vegetables a day, which has been identified as optimal for health (i.e., adequate fruit/vegetable consumption), and non-communicable diseases (NCDs) in low- and middle-income countries (LMICs) is largely unknown. Therefore, using data from six LMICs, we investigated the independent association between inadequate fruit/vegetable consumption and 12 NCDs, and estimated the prevalence of inadequate fruit/vegetable consumption among people with NCDs. DESIGN AND SETTING: Cross-sectional, nationally representative data from the WHO Study on global AGEing and adult health (SAGE) were analyzed. PARTICIPANTS: Data on 34129 individuals aged ≥50 years were analyzed [mean (SD) age 62.4 (16.0); maximum age 114 years; 52.1% females]. MEASUREMENTS: Information on the number of servings of fruits and vegetables consumed on a typical day was self-reported. Twelve NCDs were assessed. Multivariable logistic regression analysis was conducted. RESULTS: Overall, 67.2% had inadequate fruit/vegetable consumption. Inadequate fruit/vegetable consumption was independently associated with significantly higher odds for chronic lung disease (OR=1.25), diabetes (OR=1.45), hearing problems (OR=1.75), and visual impairment (OR=2.50). The prevalence of inadequate fruit/vegetable consumption was particularly high among people with visual impairment (92.5%), depression (90.5%), asthma (79.8%), and hearing problems (78.4%). CONCLUSION: Promotion of fruit and vegetable consumption (≥2 servings of fruits and ≥3 servings of vegetables a day) in LMICs may lead to prevention of some NCDs (e.g., diabetes, chronic lung disease). Furthermore, people with certain NCDs (e.g., visual impairment, depression) had particularly high prevalence of inadequate fruit/vegetable consumption, and it is thus important to target this population to increase fruit/vegetable consumption.

Social environmental impact of COVID-19 and erectile dysfunction: an explorative review.

BACKGROUND: To date, no attempt has been made to collate literature on the relationship between the social environmental impact of COVID-19 and erectile dysfunction. The aim of this explorative review was to assess and compare the prevalence of erectile dysfunction (ED) in male healthcare workers and males during the COVID-19 pandemic. METHODS: A systematic review of major databases from inception to February 2021 was conducted. Prevalence data were extracted, and a random-effects meta-analysis was undertaken. OUTCOMES: The pooled prevalence of ED amongst healthcare workers working in COVID-19 specific environments, and non-healthcare during the COVID-19 pandemic. RESULTS: Of 52 initial studies, six were included for the final analysis. The pooled prevalence of ED in healthcare workers working in a COVID-19 environment was 63.6% (95% CI 20.3-92.3%), and in non-healthcare workers during the COVID-19 pandemic was 31.9% (95% CI 19.5-47.6%). CONCLUSION: The prevalence of ED in healthcare workers working in COVID-19 environments was higher than representative samples and is of concern. Sexual health (and by extension, overall health), should be a priority when considering ways to care for this population. Considering the social environmental impact of COVID-19 on sexual health and in particular on ED, it is important to provide adequate psychological support systems and to promote quality of life with particular attention to sexual health.

Physical activity, sedentary behaviour and cannabis use in 15,822 US adults: cross-sectional analyses from NHANES.

OBJECTIVES: The aim was to analyse the overall and sex-specific associations between cannabis use and physical activity and sedentary behaviour. STUDY DESIGN: Cross-sectional analyses from the National Health and Nutrition Examination Survey (NHANES). METHODS: Data on cannabis use and leisure time physical activity and sedentary behaviour from NHANES cycles 2007-2008 to 2015-2016 were analysed. Multivariable regression models were carried out. RESULTS: About 15,822 participants were analysed (mean age ± standard error = 37.5 ± 0.19 years, range 20-59 years). Significantly higher odds were found for being active and ever used cannabis in the overall sample (odds ratio [OR] = 1.2, 95% confidence interval [CI]: 1.1-1.4) and in males (OR = 1.3, 95% CI: 1.1 to 1.5) and females (OR = 1.2, 95% CI: 1.0-1.4), respectively. In respective of sedentary behaviour, ever used cannabis was associated with higher odds of TV viewing ≥2 h/day in the overall sample (OR = 1.2, 95% CI: 1.0-1.4). However, this association was observed in males only (OR = 1.3, 95% CI: 1.1-1.6). Ever used cannabis was associated with total sitting time (beta-coefficient = 0.3, 95%CI: 0.1-0.4), which was more evident in females (beta-coefficient = 0.4, 95% CI: 0.1-0.6). CONCLUSIONS: Cannabis consumption was associated with higher levels of physical activity and sitting time. When intervening to reduce cannabis consumption in the US populations, it may be appropriate to promote physical activity and ensure physical activity is maintained once cannabis consumption is stopped.

Conventional and advanced imaging in neuromyelitis optica.

Myelitis and optic neuritis are prototypic clinical presentations of both multiple sclerosis and neuromyelitis optica. Once considered a subtype of multiple sclerosis, neuromyelitis optica, is now known to have a discrete pathogenesis in which antibodies to the water channel, aquaporin 4, play a critical role. Timely differentiation of neuromyelitis optica from MS is imperative, determining both prognosis and treatment strategy. Early, aggressive immunosuppression is required to prevent the accrual of severe disability in neuromyelitis optica; conversely, MS-specific therapies may exacerbate the disease. The diagnosis of neuromyelitis optica requires the integration of clinical, MR imaging, and laboratory data, but current criteria are insensitive and exclude patients with limited clinical syndromes. Failure to recognize the expanding spectrum of cerebral MR imaging patterns associated with aquaporin 4 antibody seropositivity adds to diagnostic uncertainty in some patients. We present the state of the art in conventional and nonconventional MR imaging in neuromyelitis optica and review the place of neuroimaging in the diagnosis, management, and research of the condition.

Lymphocyte cytochrome P450 expression: inducibility studies in male Wistar rats.

The cytochrome P450 system plays a key role in the metabolism of endogenous and exogenous compounds. The system is distributed widely in body tissues, with the highest concentration of the enzymes found in liver hepatocytes. Extrahepatic expression of the P450 system has been documented in the lung, pancreas and kidney, and the enzymes are induced by many disease states, including diabetes mellitus and cancer. Little attention has been paid to the expression and inducibility of the system in peripheral blood lymphocytes. In this study, specific P450 inducers are administered in vivo to male Wistar rats. The expression and in vivo induction of the P450 isoforms CYP2B, CYP2E, CYP3A and CYP4A in liver and lymphocyte samples is determined using Western blot analysis. Following in vivo induction, the lymphocyte P450 proteins showed an average three-fold increase in expression (0.003-0.005 microg P450/microg microsomal protein), compared to the control lymphocyte samples. Expression in the induced lymphocyte samples was up to 11-fold lower than that in the induced liver samples, as expected. These results indicate that lymphocytes may provide a relatively simple method by which to monitor the P450 profile in human subjects.

Influence of habitual diet on antioxidant status: a study in a population of vegetarians and omnivores.

BACKGROUND: Antioxidant status can be used as a biomarker to assess chronic disease risk and diet can modulate antioxidant defence. OBJECTIVE: To examine effects of vegetarian diet and variations in the habitual intakes of foods and nutrients on blood antioxidants. SUBJECTS AND SETTING: Thirty-one vegetarians (including six vegans) and 58 omnivores, non-smokers, in Northern Ireland. DESIGN: A diet history method was used to assess habitual diet. Antioxidant vitamins, carotenoids, uric acid, zinc- and ferric-reducing ability of plasma (FRAP) were measured in fasting plasma and activities of glutathione peroxidase (GPX), superoxide dismutase (SOD) and glutathione S-transferase (GST) and level of reduced glutathione (GSH) were measured in erythrocytes. RESULTS: Vegetarians had approximately 15% higher levels of plasma carotenoids compared with omnivores, including lutein (P< or =0.05), alpha-cryptoxanthin P< or =0.05), lycopene (NS), alpha-carotene (NS) and beta-carotene (NS). The levels/activities of all other antioxidants measured were similar between vegetarians and omnivores. Total intake of fruits, vegetables and fruit juices was positively associated with plasma levels of several carotenoids and vitamin C. Intake of vegetables was positively associated with plasma lutein, alpha-cryptoxanthin, alpha-carotene and beta-carotene, whereas intake of fruits was positively associated with plasma beta-cryptoxanthin. Intake of tea and wine was positively associated with FRAP value, whereas intake of herbal tea associated positively with plasma vitamin C. Intakes of meat and fish were positively associated with plasma uric acid and FRAP value. CONCLUSIONS: The overall antioxidant status was similar between vegetarians and omnivores. Good correlations were found between intakes of carotenoids and their respective status in blood.

Investigation of systemic folate status, impact of alcohol intake and levels of DNA damage in mononuclear cells of breast cancer patients.

Folate is required for DNA synthesis, repair and methylation. Low folate status has been implicated in carcinogenesis, possibly as a result of higher rate of genetic damage. The aim of this study is to compare folate status and levels of DNA damage between breast cancer and benign breast disease control patients. Fasting blood samples from 64 histologically confirmed untreated breast cancer patients (mean age 57 years) and 30 benign breast disease control patients (mean age 51 years) were obtained. Red cell folate (RCF) and plasma homocysteine were measured. Mononuclear cells (MNC) were isolated for genetic damage analysis using the basic alkaline comet assay. Results are expressed as tail moment. Data were log transformed as appropriate before analysis for normalisation purposes. The geometric mean (95% confidence interval) of RCF (ng ml(-1)) in breast cancer patients was 339.07 (333.3-404.6) vs 379.5 (335.8-505.2) in control patients (P = 0.24). Corresponding plasma homocysteine concentrations (micromol l(-1)) were 11.9 (10.6-16.4) vs 10.1 (9.3-11.9) (P = 0.073), respectively. The mean tail moment (s.d.) of DNA damage in MNC of breast cancer patients detected by the basic comet assay was 1.4 (0.66) vs -0.17 (0.79) in controls (P < 0.0001, t-test), the modified comet assay 'endonuclease III (Endo III)' was 1.7 (0.70) vs 0.86 (0.81) (P < 0.0001, t-test), and the modified comet assay 'formamidopyrimidine glycosylase (FPG)' was 1.6 (0.62) vs 0.99 (0.94) (P < 0.0001, t-test). There was a significant negative correlation between RCF levels and DNA damage detected by modified comet assay 'FPG' (Pearson Correlation Coefficient r2 = -0.26, P = 0.02) and DNA damage was found to be significantly higher in MNC of breast cancer patients compared to benign breast disease control patients. Breast cancer patients tended to have lower RCF levels and higher levels of plasma homocysteine, but these differences were not significant. The study provides preliminary evidence that reduced folate status may be implicated in the aetiology of breast cancer perhaps by increasing the in vivo level of genetic instability.

Food additive lactic acid production by immobilized cells of Lactobacillus brevis on delignified cellulosic material.

Improvements in yield and productivity in lactic acid fermentation by Lactobaccilus brevis cells immobilized on delignified cellulosic (DC) material are reported. The system proved to be more efficient in comparison with the work reported by other workers. Yields of 80 and 100% conversion using glucose were obtained at 30 degrees C in 1 day of fermentation time. Lactic acid fermentation using whey as substrate was obtained at 30 degrees C in 1-1.5 days, resulting in 70% yield, whereas the remaining lactose in whey was converted to alcohol byproduct, leading to a 90% lactose exploitation and 100% conversion. Cell immobilization of L. brevis on DC material was proved by its reuses in repeated batch fermentations and through electron microscopy. A series of 10 repeated batch fermentations without any loss in cell activity showed a tendency for high operational stability. The presence of DC material resulted in a drastic drop of the fermentation time from 48 to 13 h.

Age-related accumulation of oxidative DNA damage and alterations in levels of p16(INK4a/CDKN2a), p21(WAF1/CIP1/SDI1) and p27(KIP1) in human CD4+ T cell clones in vitro.

T cells in vivo have been shown to accumulate DNA damage with age. To investigate the effects of DNA damage on T cell biology we have utilised an in vitro human CD4+ T cell clone model. Levels and types of DNA damage were determined in 11 independent T cell clones as a function of their in vitro lifespan. Increased levels of reactive oxygen species (ROS) induced DNA damage with increasing age were found in all clones analysed using a modified alkaline comet assay. T cell clones underwent apoptosis at the end of their lifespans. There were no consistent changes in the mRNA levels for the cyclin-dependent kinase inhibitors (CKI) p16, p21, and p27 during the clones' lifespans. It appears that the increased levels of ROS induced DNA damage in the T cells is not the major trigger of apoptosis, via the p53/p21 pathway. In addition, at the end of their lifespans, the T cell clones did not display the CKI phenotype reported for senescent cells (an increase in p16 and p21 levels). Thus, while the T cell clones appear sensitive to ROS-induced DNA damage, the molecular mechanisms through which this influences T cell dysfunction with age remains to be elucidated.

Mitochondrial DNA polymorphism: its role in longevity of the Irish population.

The mtDNA genome has been implicated as playing a pivotal role in determining the longevity and success of the human lifespan. A PCR-RFLP methodology was used to identify polymorphic restriction enzyme sites within a 2643 bp region of the mtDNA genome and a table of genetic haplotypes for a healthy aged and a younger control cohort of patients was constructed. Forty-six different mtDNA haplotypes and 11 groups of related haplotypes were identified across the two age groups but statistical analysis failed to show any significant associations. The European J haplogroup, previously reported to be associated with longevity, was not found at an increased frequency within the Irish aged population (P=0.36). However, the haplotypes comprising the J haplogroup could be differentiated into two distinct branches by the presence or absence of the two polymorphic restriction sites, 16,389g and 16,000g. The branch of haplotypes defined by 16,389g displayed a significant increased frequency in the aged samples (8%) compared to the controls (1%), P=0.015. Inversely, the branch of haplotypes defined by 16,000g displayed a significant decreased frequency in the aged samples (4%) compared to the controls (13%), P=0.011. The polymorphism (mt5178A) associated with longevity in the Japanese was not found in the Irish population, while the polymorphism (mt9055A) associated with successful ageing in the French centenarians was found at an increased frequency in the Irish aged population (9%) compared to the younger control group (5%), but failed to reach a level of statistical significance, P=0.164.

Lymphocyte cytochrome P450-CYP2E1 expression in human IDDM subjects.

Cytochrome P4502E1, a phase I enzyme, has been shown to be induced in liver samples from diabetic and obese rats. One study demonstrated elevated levels of CYP2E1 in children with IDDM, using Western blot analysis. The aim of this investigation was to determine CYP2E1 expression in peripheral blood lymphocytes from eight well-controlled IDDM and eight sex- and age-matched control subjects using Western blot analysis and Phoretix image analysis. Levels of CYP2E1 were low to undetectable in human lymphocytes from healthy control subjects. However, levels of CYP2E1 were elevated in lymphocytes from IDDM subjects (mean 3.1-fold higher). The elevated levels of CYP2E1 in the IDDM subjects showed no correlation with HbA(1c) nor duration of IDDM; however, there were marked inter-individual differences in levels of induction of CYP2E1 between all subjects. The results of this study suggest that in human IDDM subjects, even with good metabolic control, expression of CYP2E1 is elevated when compared to controls. CYP2E1 is known to generate ROS in vivo, the modulation of this isoform in lymphocytes from IDDM subjects, could well add to the oxidative stress associated with IDDM and the development of associated complications.

The effect of vitamin C or vitamin E supplementation on basal and H2O2-induced DNA damage in human lymphocytes.

There is a wealth of epidemiological information on antioxidants and their possible prevention of disease progression but very little of the research on antioxidants has involved intervention studies. In this study, the potential protective effect of vitamin C or E supplementation in vivo against endogenous and H2O2-induced DNA damage levels in lymphocytes was assessed. The supplementation involved fourteen healthy male and female non-smokers mean age 25-53 (SD 1.82) years, who were asked to supplement an otherwise unchanged diet with 1000 mg vitamin C daily for 42 d or 800 mg vitamin E daily for 42 d. DNA damage in H2O2-treated peripheral blood lymphocytes (PBL) and untreated PBL before and after supplementation, and during a 6-week washout period was assessed using an ELISA. At each sampling time-point, the red cell concentrate activities of superoxide dismutase, catalase and glutathione peroxidase were also determined. Supplementation with vitamin C or vitamin E decreased significantly H2O2-induced DNA damage in PBL, but had no effect on endogenous levels of DNA damage. The activities of the antioxidant enzymes superoxide dismutase and glutathione peroxidase were suppressed during the supplementation period. These supplementation regimens may be used to limit the possible adverse effects of reactive oxygen species (including those produced during the course of an immune response) on lymphocytes in vivo, and so help to maintain their functional capacity.

Effect of a dCTP:dTTP pool imbalance on DNA replication fidelity in Friend murine erythroleukemia cells.

Nucleotide pool imbalances have been reported to affect the fidelity of DNA replication and repair in prokaryotic and eukaryotic cells. We have reported previously that the mutagen-hypersensitive thymidine kinase (TK)-deficient Friend erythroleukemia (FEL) cells (subclones 707BUF and 707BUE), have a more than sixfold increase in the dCTP:dTTP pool ratio when compared to that of wild-type, TK-positive (TK(+)) clone 707 cells. In this study we present the results of an investigation of the effect of the dCTP:dTTP pool imbalance on the accuracy of DNA replication within 707BUF cells. We examined the spontaneous mutation spectra occurring at the adenine phosphoribosyltransferase (aprt) locus within clone 707 (TK(+)) and 707BUF (TK(-)) FEL cells. Mutations recovered at the aprt locus in FEL cells comprised: base substitutions (43:73), frameshifts (14:13.5), and deletions (43:13.5) [clone 707 (TK(+)):707BUF (TK(-)), respectively, expressed as percentages]. A comparison of the mutation spectra obtained for the two cell lines did not reveal any significant increase in misincorporation of dCTP, the nucleotide in excess, in 707BUF (TK(-)) cells, during DNA replication synthesis. These data suggest that the dCTP:dTTP pool imbalance does not alter the fidelity of DNA replication synthesis in 707BUF (TK(-)) FEL cells. Rather, the predominance of GC --> AT transitions (53%) in the 707BUF (TK(-)) spectrum may reflect a reduced efficiency of repair by uracil DNA glycosylase of uracil residues within these cells.

Levels of peripheral blood cell DNA damage in insulin dependent diabetes mellitus human subjects.

Increased production of reactive oxygen species (ROS) in vivo can lead to cellular biomolecule damage. Such damage has been suggested to contribute to the pathogenesis of insulin dependent diabetes mellitus (IDDM). In this study, we used the alkaline comet assay to measure DNA damage (single-stranded DNA breaks and alkali-labile sites) in freshly isolated whole blood, lymphocytes, monocytes, and neutrophils from 23 subjects with IDDM and 32 age- and sex-matched controls. Analysis of the results showed elevated levels of DNA damage (expressed as % comet tail DNA) in the lymphocyte (4.10+/-0. 47, 3.22+/-0.22), monocyte (4.28+/-0.47, 3.49+/-0.18), and whole blood (4.93+/-0.51, 4.51+/-0.23) fractions from IDDM subjects compared to controls, respectively, but the increases observed were not statistically significant. However, we found significantly elevated basal levels of DNA damage in the neutrophil fraction (8. 38+/-0.64, 4.07+/-0.23; p<0.001, Mann-Whitney U test) in IDDM subjects compared to controls. Given these novel neutrophil findings, we extended the study to include a total of 50 IDDM subjects and 50 age- and sex-matched control subjects and determined basal levels of DNA damage in the neutrophils of all 100 subjects. We found significantly elevated mean levels of DNA damage (8.40+/-0.83, 4. 34+/-0.27; p<0.001, Mann-Whitney U test) in the neutrophils from the IDDM subjects when compared to controls. Our results show that even with acceptable glycaemic control there is a significantly elevated level of DNA damage within diabetic neutrophils in vivo.

The effects of carnosine on oxidative DNA damage levels and in vitro lifespan in human peripheral blood derived CD4+T cell clones.

Carnosine (beta-alanyl-L-histidine), an abundant naturally-occurring dipeptide has been shown to exhibit anti-ageing properties towards cultured cells, possibly due in part to its antioxidant/free radical scavenging abilities. In this paper the results of an investigation on the effects of carnosine, at the physiological concentration of 20 mM, on oxidative DNA damage levels and in vitro lifespan in peripheral blood derived human CD4+ T cell clones are reported. Under the culture conditions used (20% O(2)) long term culture with carnosine resulted in a significant increase in the lifespan of a clone derived from a healthy young subject. No such extension was observed when a T cell clone from a healthy old SENIEUR donor was similarly cultured. Culture with carnosine from the midpoint of each clone's lifespan did not have any effect on longevity, independent of donor age. Oxidative DNA damage levels were measured in the clones at various points in their lifespans. Carnosine acted as a weak antioxidant, with levels of oxidative DNA damage being lower in T cells grown long term in the presence of carnosine. The possibility that carnosine might confer anti-ageing effects to T cells under physiological oxygen tensions would appear to be worthy of further investigation.

Mutation and the Aging Process : Mutant Frequency at the HPRT Gene Locus as a Function of Age in Humans.

Aging is a complex, biological process that is contributed to by intrinsic (genetic) and extrinsic (nutrition, infectious agents, xenobiotic exposure, etc.) factors (1). Several decades ago it was first proposed that instabilities in the organization and expression of the genetic material was likely to be involved in the aging process (reviewed in ref. 2). Indeed, since that time much experimental evidence has been published that details increases in DNA damage (3-8) and mutation (8, 9-15) in various cells and tissues with age in humans.

Antioxidant status in humans after exposure to hyperbaric oxygen.

Hyperbaric oxygen (HBO) treatment (i.e., exposure to 100% oxygen at a pressure of 2.5 atmosphere absolute (ATA) for a total of 3 x 20 min periods) of human subjects induced DNA damage in the alkaline comet assay with leukocytes and protected against the DNA damaging effects of subsequent in vivo HBO exposures. Furthermore, blood taken 24 h after the first HBO was well protected against the in vitro induction of genotoxic effects by hydrogen peroxide. To investigate the mechanisms which led to this apparent adaptive response, we determined the antioxidant status of blood from subjects before and after HBO. We did not find differences in the plasma concentrations of the antioxidant vitamins A, C and E after HBO treatment. HBO had also no effect on the 'antioxidant power' of the plasma as measured with the FRAP-assay or on the concentration of reduced glutathione determined in the plasma or in lymphocytes. Red cell concentrate activities of superoxide dismutase, catalase, glutathione peroxidase were not influenced by HBO. In contrast, synthesis of the heat shock protein HSP70 which has been implicated to play an important role in cellular protection against oxidative stress, was significantly induced in lymphocytes after a single HBO treatment. To investigate whether intake of antioxidants may protect against HBO-induced DNA damage, we supplemented subjects with vitamin E (800 mg for 7 days) or with N-acetylcysteine (400 mg, 1 h before the HBO treatment). However, these supplementations did not influence the induction of DNA damage by HBO.

T cells and aging (update february 1999).

Deterioration of the immune system with aging ("immunosenescence") is believed to contribute to morbidity and mortality in man due to the greater incidence of infection, as well as possibly autoimmune phenomena and cancer in the aged. Dysregulation of T cell function is thought to play a critical part in these processes. Factors contributing to T cell immunosenescence may include a) stem cell defects, b) thymus involution, c) defects in antigen presenting cells (APC), d) aging of resting immune cells, e) disrupted activation pathways in immune cells, f) replicative senescence of clonally expanding cells. This review aims to consider the current state of knowledge on the scientific basis for and potential clinical relevance of those factors in immunosenescence.

Validation of the human T-lymphocyte cloning assay--ring test report from the EU concerted action on HPRT mutation (EUCAHM).

The T-cell cloning assay, which enables the enumeration and molecular analysis of 6-thioguanine resistant (HPRT-negative) mutant T-cells, has been extensively used for studying human somatic gene mutation in vivo. However, large inter-laboratory variations in the HPRT mutant frequency (MF) call for further investigation of inter-laboratory differences in the experimental methodology, and development of an optimal but easy uniform cloning protocol. As part of the EU Concerted Action on HPRT Mutation (EUCAHM), we have carried out two Ring tests for the T-cell cloning assay. For each test, duplicate and coded samples from three buffy coats were distributed to five laboratories for determination of MF using six different protocols. The results indicated a good agreement between split samples within each laboratory. However, both the cloning efficiencies (CEs) and MFs measured for the same blood donors showed substantial inter-laboratory variations. Also, different medium compositions used in one and the same laboratory resulted in a remarkable difference in the level of MF. A uniform operating protocol (UOP) was proposed and compared with the traditional protocols in the second Ring test. The UOP (preincubation) increased the CE in laboratories traditionally using preincubation, but decreased the CE in laboratories traditionally using priming. Adjusted for donor, use of different protocols contributed significantly to the overall variation in lnCE (P = 0.0004) and lnMF (P = 0.03), but there was no significant laboratory effect on the lnCE (P = 0.38) or lnMF (P = 0.14) produced by the UOP alone. Finally, a simplified version of the UOP using the serum-free medium X-Vivo 10 and PMA was tested in one laboratory, and found to produce a considerable increase in CE. This modified UOP needs to be further evaluated in order to be used for future databases on HPRT MFs in various populations.

Effect of dietary intake and lifestyle factors on in vivo mutant frequency at the HPRT gene locus in healthy human subjects.

This paper describes the results of a study designed to assess the effects of a variety of dietary and lifestyle factors on background levels of mutant frequency (MF) at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene locus in humans. Eighty-three healthy and free-living subjects (aged 20-80 yr; 61 males and 22 females; mean age of 63.07 +/- 14.71 yr) were recruited. Background levels of MF were determined for each subject using a cloning assay. The mean MF/10(6) clonable cells (MF) for the study subjects was 4.63 +/- 2.20. An interview-administered questionnaire was completed by each study subject in order to assess details of dietary history, physical activity, health and potential genotoxin exposure history. A 7-day estimated dietary record method with a food frequency questionnaire was used to determine average intakes of energy and macronutrients (including alcohol), and a range of micronutrients (including vitamin and mineral supplement usage). The relationships between individual dietary and lifestyle factors and HPRT MF were investigated by univariate and multivariate analysis (data was adjusted for age, lymphocyte plating efficiency [PE] and energy intake [EI]). Univariate analysis revealed a significant positive correlation between EI and MF and multivariate analysis revealed significant positive correlations between, body mass index (BMI), % energy intake from total carbohydrate, starch, fat and MF. These findings suggest that a reduction in EI may be a useful preventative measure against the onset of carcinogenesis in humans. No correlations were found between alcohol intake and MF or between estimated antioxidant intake and MF. Thus, estimated intakes of antioxidants may not reflect their bioavailability and functional capacity in vivo and it may be more useful to examine actual plasma/cell levels vs. MF to establish if any significant relationship exists.