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1.
J Nutr Health Aging ; 10(1): 37-44, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16453056

RESUMEN

Previous studies have suggested that vitamin C status may be associated with cognitive function in community-dwelling populations. However, this has not been consistent across all studies due to methodological differences. This cross-sectional study assessed the association between vitamin C and cognitive function in 544 community-dwelling older adults aged 65 or older who participated in both the Cardiovascular Health Study (CHS) and the CLUE II study in 1989. Three percent of the subjects had low plasma vitamin C concentrations (< 40 mg/dL) and 15% had low total vitamin C intake (< 60 mg/day). Most participants (96.7 percent) had normal cognitive function. In the unadjusted analyses, the highest fifth of plasma vitamin C concentration was associated with better Digit Symbol Substitution Test (DSST) scores and marginally associated with Mini-Mental State Examination (MMSE) compared to the lowest fifth. Total vitamin C intake, measured by Block's food frequency questionnaire, was generally associated with higher MMSE scores, though it was not significant. Adjusting for numerous factors did not substantially change results. In a stratified analysis by gender, higher plasma concentrations or intake were associated with higher MMSE scores for men but not for women. These mixed results do not provide strong evidence of an association between vitamin C concentrations or intake and cognitive function.


Asunto(s)
Ácido Ascórbico/administración & dosificación , Ácido Ascórbico/sangre , Cognición/efectos de los fármacos , Cognición/fisiología , Dieta , Anciano , Envejecimiento/fisiología , Estudios Transversales , Femenino , Encuestas Epidemiológicas , Humanos , Masculino , Escala del Estado Mental , Encuestas Nutricionales , Necesidades Nutricionales , Factores Sexuales , Encuestas y Cuestionarios
2.
J Natl Cancer Inst ; 88(1): 32-7, 1996 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-8847723

RESUMEN

BACKGROUND: Antioxidant micronutrients, such as alpha-tocopherol (vitamin E), the carotenoids, and selenium, may protect against the development of cancer by preventing free radical damage at the cellular level. PURPOSE: A nested case--control study was conducted among donors to a serum bank to examine the association between levels of serum micronutrients and/or cholesterol and the development of ovarian cancer. METHODS: In 1974, sera were collected from 20,305 residents of Washington County, MD, over a 4-month period and stored at -70 degrees C. Serum micronutrient concentrations of women who developed ovarian cancer (case subjects, n = 35) were compared with those of women who remained free of cancer and who were matched to case subjects on age and menopausal status (control subjects, n = 67). Serum levels of retinol (vitamin A), alpha- and beta-carotene (the major provitamin A), lycopene (a carotenoid), and alpha- and gamma-tocopherol were measured using high-performance liquid chromatography. Serum selenium was measured by neutron activation analysis. Cholesterol was measured by enzymatic assay. The data were categorized into thirds and conditional logistic regression analyses were performed to determine the association between prediagnostic serum cholesterol and micronutrient levels and the development of ovarian cancer; matched odds ratios (ORs) were determined from these regression analyses. P values for trend and for interaction were calculated with the use of two-sided likelihood ratio tests. RESULTS: Higher serum alpha-tocopherol levels were associated with an increased risk of ovarian cancer (P for trend = .04); however, this association diminished after adjustment for cholesterol. Women with higher serum cholesterol levels had an increased risk of ovarian cancer compared with women in the lowest third of cholesterol levels (OR = 3.2; 95% confidence interval = 0.9-11.3). The association between serum cholesterol levels and the risk of ovarian cancer was examined, stratifying by micronutrient level. The general pattern observed was an increased risk of ovarian cancer associated with cholesterol levels greater than 200 mg/dL, regardless of the micronutrient level. Serum selenium was associated with a decreased risk of ovarian cancer only among case participants diagnosed 4 or more years after blood collections (P for trend = .02). Concentrations of carotenoids and retinol were not associated with the development of ovarian cancer. CONCLUSIONS: Selenium may have a protective role against the development of ovarian cancer. Higher serum cholesterol levels were associated with an increased risk of developing ovarian cancer; an association that persisted regardless of serum micronutrient level. IMPLICATIONS: Given the small size of this study and the inconsistency of results among the few prospective studies of ovarian cancer conducted to test these associations, replications of these findings are highly desirable.


Asunto(s)
Micronutrientes/metabolismo , Neoplasias Ováricas/sangre , Carotenoides/sangre , Estudios de Casos y Controles , Colesterol/sangre , Femenino , Humanos , Persona de Mediana Edad , Oportunidad Relativa , Estudios Prospectivos , Selenio/sangre , Vitamina A/sangre , Vitamina E/sangre
3.
J Natl Cancer Inst ; 92(24): 2018-23, 2000 Dec 20.
Artículo en Inglés | MEDLINE | ID: mdl-11121464

RESUMEN

BACKGROUND: Selenium and alpha-tocopherol, the major form of vitamin E in supplements, appear to have a protective effect against prostate cancer. However, little attention has been paid to the possible role of gamma-tocopherol, a major component of vitamin E in the U.S. diet and the second most common tocopherol in human serum. A nested case-control study was conducted to examine the associations of alpha-tocopherol, gamma-tocopherol, and selenium with incident prostate cancer. METHODS: In 1989, a total of 10,456 male residents of Washington County, MD, donated blood for a specimen bank. A total of 117 of 145 men who developed prostate cancer and 233 matched control subjects had toenail and plasma samples available for assays of selenium, alpha-tocopherol, and gamma-tocopherol. The association between the micronutrient concentrations and the development of prostate cancer was assessed by conditional logistic regression analysis. All statistical tests were two-sided. RESULTS: The risk of prostate cancer declined, but not linearly, with increasing concentrations of alpha-tocopherol (odds ratio (highest versus lowest fifth) = 0.65; 95% confidence interval = 0.32--1.32; P(trend) =.28). For gamma-tocopherol, men in the highest fifth of the distribution had a fivefold reduction in the risk of developing prostate cancer than men in the lowest fifth (P:(trend) =.002). The association between selenium and prostate cancer risk was in the protective direction with individuals in the top four fifths of the distribution having a reduced risk of prostate cancer compared with individuals in the bottom fifth (P(trend) =.27). Statistically significant protective associations for high levels of selenium and alpha-tocopherol were observed only when gamma-tocopherol concentrations were high. CONCLUSIONS: The use of combined alpha- and gamma- tocopherol supplements should be considered in upcoming prostate cancer prevention trials, given the observed interaction between alpha-tocopherol, gamma-tocopherol, and selenium.


Asunto(s)
Neoplasias de la Próstata/sangre , Neoplasias de la Próstata/etiología , Selenio/administración & dosificación , Selenio/sangre , Vitamina E/administración & dosificación , Vitamina E/sangre , Anciano , Estudios de Casos y Controles , Humanos , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Neoplasias de la Próstata/prevención & control , Riesgo , Factores de Riesgo
4.
Cancer Res ; 46(10): 5392-400, 1986 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3756889

RESUMEN

Gas chromatography-high resolution mass spectrometry methods were developed for quantifying nitrosodimethylamine (NDMA) and nitrosoproline (NPRO) in human urine. The limits of quantitation of these methods, which utilize stable isotope analogues of NDMA and NPRO as internal standards, were 5 pg per ml for NDMA and 0.14 ng per ml for NPRO. The assays were used to quantify NDMA and NPRO in urine samples collected 4 times a wk for 5 wk from 24 healthy volunteers. The mean urinary excretion of NDMA during this time was found to be 38.2 ng per day, and the mean urinary excretion of NPRO was found to be 3.26 micrograms per day. Treatment of the volunteers with 600 mg of ascorbic acid and 100 IU of alpha-tocopherol 4 times a day for the final 3 wk of the study did not influence the urinary excretion of NDMA or NPRO. Considerable person-to-person and day-to-day variations were observed for the urinary excretion of both nitrosamines, but the urinary excretion of NDMA was not correlated with the urinary excretion of NPRO. Person-to-person and day-to-day differences in the urinary excretion were greater for NPRO than for NDMA. The mean urinary excretion of NDMA by the 24 subjects was as much as 5-fold higher on some days than on other days, but this was not observed for NPRO. Day-to-day differences in the mean urinary excretion of NDMA were correlated with the concentrations of nitrogen dioxide in the air.


Asunto(s)
Ácido Ascórbico/farmacología , Dimetilnitrosamina/orina , Nitrosaminas/orina , Vitamina E/farmacología , Adulto , Anciano , Aire/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dióxido de Nitrógeno/análisis
5.
Cancer Res ; 53(4): 795-8, 1993 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-8428360

RESUMEN

To investigate the relationship between serum micronutrients and the subsequent risk of oral and pharyngeal cancer, a nested case-control study was conducted within a cohort of 25,802 adults in Washington County, MD, whose blood samples were collected in 1974 and stored at -70 degrees C for subsequent assays. The serum levels of nutrients in 28 individuals who developed oral and pharyngeal cancer during 1975 to 1990 were compared with levels in 112 matched controls. Serum levels of all individual carotenoids, particularly beta-carotene, were lower among subjects who developed oral and pharyngeal cancer. The risks of this malignancy decreased substantially with increasing serum level of each individual carotenoid. Persons in the highest tertile of total carotenoids had about one-third the cancer risk as those in the lowest tertile. High serum levels of alpha-tocopherol also were related to a low oral cancer risk in later years, but the risks were elevated significantly with increasing serum levels of gamma-tocopherol and selenium. The findings from this study are consistent with many previous epidemiological investigations of dietary factors for oral and pharyngeal cancer and provide further evidence for the potential role of carotenoids and alpha-tocopherol in the chemoprevention of these malignancies.


Asunto(s)
Carotenoides/sangre , Neoplasias de la Boca/sangre , Neoplasias Faríngeas/sangre , Selenio/sangre , Vitamina A/sangre , Vitamina E/sangre , Estudios de Casos y Controles , Humanos , Neoplasias de la Boca/etiología , Neoplasias Faríngeas/etiología , Factores de Riesgo , Fumar/sangre , beta Caroteno
6.
Biochim Biophys Acta ; 1086(1): 134-8, 1991 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-1954240

RESUMEN

Several lines of evidence indicate that oxidized LDL (Ox-LDL) may promote atherogenesis. Hence, the role of antioxidants in the prevention of LDL oxidation needs to be determined. beta-Carotene, in addition to being an efficient quencher of singlet oxygen, can also function as a radical-trapping antioxidant. Since previous studies have failed to show that beta-carotene inhibits LDL oxidation, we re-examined its effect on the oxidative modification of LDL. For these studies, LDL was oxidized in both a cell-free (2.5 microM Cu2+ in PBS) and a cellular system (human monocyte macrophages in Ham's F-10 medium). beta-Carotene inhibited the oxidative modification of LDL in both systems as evidenced by a decrease in the lipid peroxide content (thiobarbituric-acid-reacting substances activity), the negative charge of LDL (electrophoretic mobility) and the formation of conjugated dienes. By inhibiting LDL oxidation, beta-carotene substantially decreased its degradation by macrophages. beta-Carotene (2 microM) was more potent than alpha-tocopherol (40 microM) in inhibiting LDL oxidation. Thus, beta-carotene, like ascorbate and alpha-tocopherol, inhibits LDL oxidation and might have an important role in the prevention of atherosclerosis.


Asunto(s)
Antioxidantes/farmacología , Carotenoides/farmacología , Lipoproteínas LDL/efectos de los fármacos , Sistema Libre de Células , Humanos , Técnicas In Vitro , Lipoproteínas LDL/metabolismo , Macrófagos/metabolismo , Oxidación-Reducción/efectos de los fármacos , beta Caroteno
7.
World J Gastroenterol ; 11(45): 7078-83, 2005 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-16437651

RESUMEN

AIM: To compare upper gastric endoscopic and histopathologic findings in older adults in the presence and absence of B12 deficiency. METHODS: A prospective analysis of upper gastric endoscopic and gastric histopathologic findings from 30 newly identified B12-deficient patients (11 males, 19 females) and 16 controls with normal B12 status (6 males, 10 females) was performed. For all subjects, the indication for upper endoscopy and gastric biopsy were unrelated to B12 status. A single pathologist, blinded to B12 status, processed and interpreted the biopsy samples. Endoscopic and histopathologic findings were correlated with age, gender, hematocrit (Hct), MCV and B12 status. RESULTS: The B12-deficient group had significantly lower mean serum B12 levels compared to the controls (P<0.00005) while their mean Hct, MCV and serum albumin levels were similar. Iron deficiency (ferritin-based) was present in 21% of B12-deficient patients and intrinsic factor antibodies were present in 29% (5/17) of B12-deficient patients. The endoscopic findings revealed significantly different rates of gastritis and atrophy between the B12-deficient and control groups (P=0.017). B12-deficient patients had significantly less superficial gastritis (62% vs 94%) and significantly more atrophic gastritis (28% vs 0%) as compared to the controls (P=0.039). Intestinal metaplasia was similar in both groups. Helicobacter pylori infection rates were similar in the B12-deficient patients and controls (40% vs 31%). CONCLUSION: Significantly different endoscopic findings and types of gastritis could often be observed in the presence and absence of B12 deficiency. Atrophy, based on endoscopy, and atrophic gastritis, based on histopathology, suggest the presence of B12 deficiency. Gastric histopathology is not influenced by the age, gender, Hct or MCV of the patients.


Asunto(s)
Mucosa Gástrica/patología , Deficiencia de Vitamina B 12/patología , Anciano , Anciano de 80 o más Años , Envejecimiento/patología , Femenino , Gastritis/complicaciones , Gastritis/patología , Gastritis Atrófica/complicaciones , Gastritis Atrófica/patología , Gastroscopía , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Deficiencia de Vitamina B 12/complicaciones
8.
Artículo en Inglés | MEDLINE | ID: mdl-7549806

RESUMEN

Aliquots from 40 plasma pools preserved with metaphosphoric acid were assayed for their ascorbic acid values after 12, 24, and 42 months of storage at -70 degrees C. Similarly, aliquots from 16 plasma pools were assayed for values of retinol, several carotenoids, and two tocopherols at 15.5, 27.5, and 51.5 months of storage at -70 degrees C. There were no indications of important losses of these antioxidant micronutrients during storage from the first to the last assay.


Asunto(s)
Ácido Ascórbico/sangre , Conservación de la Sangre , Carotenoides/sangre , Criopreservación , Plasma/química , Vitamina A/sangre , Vitamina E/sangre , Adulto , Anciano , Estabilidad de Medicamentos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Tiempo
9.
Cancer Epidemiol Biomarkers Prev ; 5(11): 913-6, 1996 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8922300

RESUMEN

Studies suggest that micronutrients such as the tocopherols, retinol, and the carotenoids have a chemopreventive action against colonic carcinogenesis and that they may be essential for the functioning and structural integrity of the gastrointestinal epithelium. In this study, we have determined the concentrations of tocopherols, retinol, and the carotenoids in human colonic epithelial cells using a noninvasive procedure developed in this laboratory (G.P. Albaugh et al., Int. J. Cancer, 52: 347-350, 1992). In subjects on a normal diet, almost all of these micronutrients were restricted to cells in the density range of rho 1.065-1.090 and rho 1.090-1.110. The lighter fraction (rho 1.033-1.064), representing the most senescent subpopulation, retained these micronutrients only when the subjects were on diets rich in vegetables. Cells isolated from subjects on their usual diets gave the following values expressed as ng/10(7) cells: alpha-tocopherol, 93-151; gamma-tocopherol, 152-280; retinol, 12-20; lutein, 4-18; cryptoxanthin, not detected; lycopene, 0-17; alpha-carotene, 3-7; and beta-carotene, 6-9. Peak responses in specific micronutrients following 5 days on a high carotenoid diet showed a lag period of at least 5 days, corresponding to the turnover rates of the epithelium itself. The evidence suggests that uptake of these micronutrients by the colonic mucosa occurs in the deep cryptal zone where the actively proliferating cells extract the nutrients from the systemic circulation.


Asunto(s)
Carotenoides/farmacocinética , Mucosa Intestinal/citología , Mucosa Intestinal/metabolismo , Vitamina A/farmacocinética , Vitamina E/farmacocinética , Carotenoides/metabolismo , Fraccionamiento Celular , Movimiento Celular , Colon/citología , Colon/metabolismo , Dieta , Heces/citología , Humanos , Vitamina A/metabolismo , Vitamina E/metabolismo
10.
Cancer Epidemiol Biomarkers Prev ; 4(8): 837-42, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8634654

RESUMEN

To determine the association between prediagnostic serum levels of retinol, beta-carotene, lycopene, alpha-tocopherol, and selenium and the subsequent risk of malignant melanoma, and basal and squamous cell skin cancer, a nested case-control study among residents of Washington County, MD, was performed. Cases with melanoma (n = 30), basal cell (n = 32), and squamous cell (n = 37) skin cancer who were admitted to hospital for treatment or biopsy of metastatic lesions were each matched by age, sex, and race with two controls. There were no significant associations between serum micronutrient levels and the risk of subsequent skin cancer.


Asunto(s)
Carcinoma Basocelular/etiología , Carcinoma de Células Escamosas/etiología , Melanoma/etiología , Micronutrientes/análisis , Neoplasias Cutáneas/etiología , Adulto , Anciano , Antioxidantes/análisis , Carcinoma Basocelular/sangre , Carcinoma Basocelular/epidemiología , Carcinoma de Células Escamosas/sangre , Carcinoma de Células Escamosas/epidemiología , Carotenoides/sangre , Estudios de Casos y Controles , Femenino , Humanos , Licopeno , Masculino , Maryland/epidemiología , Melanoma/sangre , Melanoma/epidemiología , Persona de Mediana Edad , Factores de Riesgo , Selenio/sangre , Sensibilidad y Especificidad , Neoplasias Cutáneas/sangre , Neoplasias Cutáneas/epidemiología , Vitamina A/sangre , Vitamina E/sangre
11.
Artículo en Inglés | MEDLINE | ID: mdl-8348056

RESUMEN

A nested case-control study was conducted in Washington County, MD, to determine whether low serum micronutrients are related to the subsequent risk of cervical cancer. Among the 15,161 women who donated blood for future cancer research during a serum collection campaign in 1974, 18 developed invasive cervical cancer and 32 developed carcinoma in situ during the period January 1975 through May 1990. For each of these 50 cases, two matched controls were selected from the same cohort. The frozen sera of the cases and their matched controls were analyzed for a number of nutrients. The mean serum levels of total carotenoids, alpha-carotene, beta-carotene, cryptoxanthin, and lycopene were lower among cases than they were among controls. When examined by tertiles, the risk of cervical cancer was significantly higher among women in the lower tertiles of total carotenoids (odds ratio 2.7; 95% confidence limit, 1.1-6.4), alpha-carotene (odds ratio, 3.1; 95% confidence limit, 1.3-7.6), and beta-carotene (odds ratio, 3.1; 95% confidence limit, 1.2-8.1) as compared to women in the upper tertiles and the trends were statistically significant. Cryptoxanthin was significantly associated with a lower risk of cervical cancer when examined as a continuous variable. Retinol, lutein, alpha- and gamma-tocopherol, and selenium were not related to cervical cancer risk. Smoking was also strongly associated with cervical cancer. These findings are suggestive of a protective role for total carotenoids, alpha-carotene and beta-carotene in cervical carcinogenesis and possibly for cryptoxanthin and lycopene as well.


Asunto(s)
Carotenoides/sangre , Selenio/sangre , Neoplasias del Cuello Uterino/etiología , Vitamina A/sangre , Vitamina E/sangre , Adulto , Carcinoma in Situ/sangre , Carcinoma in Situ/etiología , Carotenoides/análogos & derivados , Estudios de Casos y Controles , Estudios de Cohortes , Criptoxantinas , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Luteína/sangre , Licopeno , Invasividad Neoplásica , Factores de Riesgo , Fumar/efectos adversos , Fumar/sangre , Neoplasias del Cuello Uterino/sangre , Xantófilas , beta Caroteno
12.
Cancer Epidemiol Biomarkers Prev ; 10(1): 65-8, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11205491

RESUMEN

Community-wide programs to collect blood for a research serum bank were carried out in Washington County, Maryland in 1974 and 1989. Of the 8395 persons who participated in both programs, 64 were controls in a nested case-control study of the association of antioxidant micronutrients with subsequent breast cancer, and 30 and 166 were controls in similar studies of lung and prostate cancer. Assay results for five carotenoids, two retinoids, and two tocopherols in samples of blood collected 15 years apart were thus available for comparisons of micronutrient concentrations. The mean Spearman rank order correlation coefficient for all comparisons was 0.44, with two coefficients greater than 0.60 and two less than 0.30. Blood pressure readings at the two blood collections had a mean rank order correlation coefficient of 0.46. Because blood pressure readings in 1974 were shown to be significantly predictive of atherosclerosis 15-18 years later, the present results suggest that ranked concentrations of antioxidant micronutrients from a single sample are sufficiently representative to be used as predictors of subsequent concentrations and are thus suitable for assessment as risk factors for subsequent illnesses.


Asunto(s)
Carotenoides/sangre , Retinoides/sangre , Vitamina E/sangre , Anciano , Arteriosclerosis/etiología , Biomarcadores/análisis , Bancos de Sangre , Estudios de Casos y Controles , Femenino , Humanos , Hipertensión/complicaciones , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Medición de Riesgo , Sensibilidad y Especificidad , Manejo de Especímenes
13.
Cancer Epidemiol Biomarkers Prev ; 6(11): 907-16, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9367064

RESUMEN

Lung cancer cases diagnosed during the period 1975 through 1993 and matched controls were identified in the rosters of Washington County, Maryland residents who had donated blood for a serum bank in 1974 or 1989. Plasma from participants in the 1989 project was assayed for ascorbic acid; serum or plasma was assayed for participants in either project for alpha- and beta-carotene, cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Among the total group of 258 cases and 515 controls, serum/plasma concentrations were significantly lower among cases than controls for cryptoxanthin, beta-carotene, and lutein/zeaxanthin with case-control differences of -25.5, -17.1, and -10.1%, respectively. Modest nonsignificant case-control differences in a protective direction were noted for alpha-carotene and ascorbic acid. There were only trivial differences for lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Findings are reported for males and females and for persons who had never smoked cigarettes, former smokers, and current smokers at baseline. These results and those from previous studies suggest that beta-carotene is a marker for some protective factor(s) against lung cancer; that cryptoxanthin, alpha-carotene, and ascorbic acid need to be investigated further as potentially protective factors or associates of a protective factor; and that lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity are unlikely to be associated with lung cancer risk. Until specific preventive factors are identified, the best protection against lung cancer is still the avoidance of airborne carcinogens, especially tobacco smoke; second best is the consumption of a diet rich in fruits and vegetables.


Asunto(s)
Antioxidantes/metabolismo , Ácido Ascórbico/sangre , Carotenoides/sangre , Neoplasias Pulmonares/sangre , Neoplasias Pulmonares/epidemiología , Selenio/sangre , Vitamina E/sangre , Adulto , Anciano , Biomarcadores/sangre , Estudios de Casos y Controles , Femenino , Radicales Libres , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Factores de Riesgo , Fumar/metabolismo , Contaminación por Humo de Tabaco
14.
Atherosclerosis ; 119(2): 139-50, 1996 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-8808491

RESUMEN

The oxidative modification of low density lipoprotein (LDL) may play a role in the pathogenesis of atherosclerosis. Furthermore, evidence of oxidized LDL (ox-LDL) has been found in vivo. Supplementation of some animal models with antioxidants has been shown to retard the formation of aortic atherosclerosis. Ascorbate (vitamin C) is a highly potent aqueous-phase antioxidant in plasma, which has been shown in vitro to retard LDL oxidation. Cigarette smokers have reduced concentrations of ascorbate in their plasma, and their LDL may be more prone to oxidation. Hence, the objective of the present study was to examine the effect of ascorbate depletion and supplementation on the propensity of LDL to oxidize in smokers in a 6-week study. Nineteen healthy smokers followed a low ascorbate diet (< or = 30 mg/day) for 2 weeks, then were randomly assigned to receive placebo or 1000 mg ascorbate per day for 4 weeks. Blood was taken at 0 and 4 weeks of supplementation for study of LDL oxidative susceptibility. LDL was oxidized with 5 mumol/l copper. The ascorbate-supplemented group had significant increases in plasma ascorbate. The placebo group showed no change in the time course of LDL oxidation between 0 and 4 weeks. However, the ascorbate-supplemented group has a significant reduction in LDL oxidative susceptibility as measured by thiobarbituric acid-reactive substances (TBARS) and the formation of conjugated dienes. The ascorbate-supplemented group demonstrated significantly increased lag phase and decreased oxidation rate at 4 weeks compared to 0 weeks. No changes were found in the placebo group. The ascorbate-supplemented group showed no biochemical signs consistent with increased body iron stores. Supplementation of otherwise healthy smokers for 4 weeks with 1000 mg ascorbate per day resulted in increased plasma ascorbate and reduced LDL oxidative susceptibility.


Asunto(s)
Antioxidantes/farmacología , Arteriosclerosis/prevención & control , Ácido Ascórbico/farmacología , Lipoproteínas LDL/sangre , Fumar/sangre , Adulto , Arteriosclerosis/metabolismo , Ácido Ascórbico/sangre , Colesterol/sangre , Femenino , Radicales Libres , Humanos , Peroxidación de Lípido/efectos de los fármacos , Lipoproteínas HDL/sangre , Masculino , Persona de Mediana Edad , Oxidación-Reducción/efectos de los fármacos , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis , Vitamina E/sangre , beta Caroteno/sangre
15.
Ann N Y Acad Sci ; 258: 401-9, 1975 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-1060409

RESUMEN

Guinea pigs were fed a control (0.05%) or a high (0.5%) ascorbic acid diet during the last half of pregnancy. When the pups were tested at 5 and 10 days of life the ones from the high-ascorbic-acid group demonstrated a marked increase in 14CO2 excretion, compared with the control pups, following an intraperitoneal injection of 14C-labeled ascorbic acid. When the animals were weaned to an ascorbic-acid-deficient diet signs of scurvy appeared earlier in the pups from the high vitamin C group and their survival was shorter. When excretion of labeled CO2 in both groups was correlated with the day of onset of scurvy signs, a linear correlation was found between these two parameters, suggesting that the earlier appearance of signs of scurvy in the experimental pups is secondary to an increased rate of ascorbic acid catabolism.


Asunto(s)
Ácido Ascórbico/metabolismo , Intercambio Materno-Fetal , Preñez , Animales , Animales Recién Nacidos , Ácido Ascórbico/administración & dosificación , Ácido Ascórbico/farmacología , Deficiencia de Ácido Ascórbico/metabolismo , Deficiencia de Ácido Ascórbico/mortalidad , Peso al Nacer , Peso Corporal , Dióxido de Carbono/biosíntesis , Dieta , Conducta Alimentaria/efectos de los fármacos , Femenino , Fertilidad/efectos de los fármacos , Cobayas , Necesidades Nutricionales , Embarazo
16.
Photochem Photobiol ; 57(4): 613-5, 1993 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8506388

RESUMEN

The photoprotective effect of topically applied alpha-tocopheryl acetate (vitamin E acetate), a stable derivative of alpha-tocopherol (vitamin E), and its possible bioconversion to the active antioxidant species (alpha-tocopherol) was examined in skin tissue of female hairless mice (HRS/J) exposed to UV-B irradiation. Our results indicate that topically applied alpha-tocopheryl acetate is absorbed into and retained by skin tissue. Furthermore, skin tissue from UV-B-irradiated animals that received daily topical alpha-tocopheryl acetate treatments contained significantly higher levels (P < 0.001) of alpha-tocopheryl acetate than non-UV-B-irradiated mice that received identical daily topical alpha-tocopheryl acetate treatments. Finally, free alpha-tocopherol levels in skin also were significantly increased (P < 0.001) by topical applications of alpha-tocopheryl acetate and skin levels of free alpha-tocopherol were significantly greater (P < 0.001) in UV-B-irradiated animals that received daily topical alpha-tocopheryl acetate treatments than in non-UV-B-irradiated animals. These results suggest that UV-B irradiation enhances both the absorption of alpha-tocopheryl acetate and its bioconversion to free alpha-tocopherol.


Asunto(s)
Piel/metabolismo , Piel/efectos de la radiación , Rayos Ultravioleta , Vitamina E/análogos & derivados , Vitamina E/metabolismo , alfa-Tocoferol/análogos & derivados , Análisis de Varianza , Animales , Transporte Biológico , Biotransformación , Femenino , Ratones , Ratones Pelados , Tocoferoles
17.
Mutat Res ; 117(1-2): 183-91, 1983 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-6403856

RESUMEN

In vitro data are presented to show that ascorbic acid does not have intrinsic mutagenicity towards strain TA100 of S. typhimurium if deionized water is used to prepare the incubation medium. The addition of Cu2+ ions to the bacterial medium that contains ascorbic acid, or the use of tap water and ascorbic acid alone, causes a mutagenic and cytotoxic response that is blocked by EDTA. Additional in vitro data demonstrate that hydrogen peroxide is mutagenic to S. typhimurium strain TA100 and it is suggested that ascorbic acid may be mutagenic and cytotoxic through the generation of hydrogen peroxide. In vivo studies using a sensitive intrahepatic host-mediated mutagenicity assay indicate that ascorbic acid is not genotoxic in guinea pigs even when the dietary intake of vitamin C is above the level required for tissue saturation (5000 mg/kg body weight/day).


Asunto(s)
Ácido Ascórbico/toxicidad , Mutágenos , Mutación , Animales , Cobre/farmacología , Ácido Edético/farmacología , Cobayas , Peróxido de Hidrógeno/toxicidad , Masculino , Pruebas de Mutagenicidad , Salmonella typhimurium/efectos de los fármacos
18.
J Am Med Dir Assoc ; 1(2): 58-61, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-12818032

RESUMEN

OBJECTIVE: To determine if older adults from long-term care facilities (LTCF) have a greater risk of death than older people in the community after the development of Clostridium difficile (CD) colitis during hospitalization. DESIGN: A retrospective review of medical records from all older hospitalized patients with a confirmed diagnosis of CD colitis from February 1995 to February 1997 at Our Lady of Mercy Medical Center, Bronx, NY, a University hospital of the New York Medical College. METHODS: A total of 108 patients (aged 60-97 yrs.) with a positive diagnosis of CD colitis (EIA of CD cytotoxin A and B) were identified. Residence (nursing home vs. community), sex and age, length of hospital stay, laboratory values, the number, dose, and duration of all antibiotics used, and co-morbid medical conditions were examined as potential risk factors for adverse outcome (mortality). RESULTS: Fifty-two nursing home and 56 older patients living in the community were compared. Outcome (survival vs. death) was equivalent between nursing home (13 of 52 died, 25% death rate) and community elderly (13 of 56 died, 23% death rate). The patients in the nursing home were, on average, 3 years older than community those in the community, but age was not related to outcome in either group. Death occurred significantly more often in LTCF and community patients who received prolonged antibiotic therapy (P = 0.0056) or were prescribed four or more antibiotics (P = 0.036) during hospitalization. Low serum albumin level was found to be a strong predictor of death (P = 0.002). However, nursing home and community elderly had similar mean serum albumin levels (P = 0.2797). Death was also predicted by the use of clindamycin alone (P = 0.046) or penicillin-like antibiotics (excluding cephalosporins) and clindamycin (P = 0.021), or a history of cardiac disease (coronary artery disease or congestive heart failure) (P = 0.022). CONCLUSIONS: Patients from LTCF do not have an increased risk of mortality compared with older people in the community after developing CD colitis during hospitalization. Factors such as low serum albumin, prolonged antibiotic therapy, the number of antibiotics used, use of specific antibiotics, and cardiac disease were significantly related to an increased risk of death in both LTCF and community older adults. Age did not influence outcome in either group of older adults.

19.
J Am Med Dir Assoc ; 2(3): 115-9, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-12812582

RESUMEN

OBJECTIVE: To compare the ambulatory status following hip fracture surgery in the acute setting between older adults from long-term care facilities (LTCF) and the community. SETTING: A 650-bed, urban, inner city, university-affiliated teaching hospital. METHODS: One hundred forty hip fracture patients (60-97 years) from long-term care facilities and the community were examined. Ambulatory status before and after surgery was categorized four ways based on the degree of independence in ambulation: A1 = independent ambulation (with or without an assisting device), A2 = assistance of another person required, A3 = predominant use of a wheelchair, and A4 = bed-bound. Change in ambulatory status was designated as "moderate" if the deterioration was one status level only (A1 to A2, A2 to A3, and A3 to A4) or "major" if the deterioration was more than one status level (A1 to A3/A4 or A2 to A4). Additional variables such as age, sex, risk factors, length of stay, history of drug use, and laboratory results also were examined. RESULTS: Hip fracture patients from LTCF were older (P = 0.0160) and had more overall risk factors for hip fracture (P = 0.0039) than community patients. They also had higher rates of dementia (P < 0.000), arrhythmia (P = 0.025), delirium (P = 0.0016) and anxiolytics use (P = 0.019) than patients from the community. On admission, LTCF patients had lower serum calcium (P = 0.0003), phosphorus (P = 0.0210), and albumin (P = 0.0004) than community patients. Before hospitalization they also were less ambulatory (P = 0.002) than community patients. Post surgery, ambulatory status declined in both groups. However, a "major" change (decline) in ambulatory status occurred more often in LTCF patients (P = 0.001). CONCLUSIONS: A greater decline in ambulatory status is seen in patients from LTCF than in community patients, immediately following hip fracture surgery. Compared with community patients, LTCF patients are also older, sicker (higher total risk score) and have an increased risk for a decline in functional status.

20.
J Am Med Dir Assoc ; 1(1): 21-4, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-12818043

RESUMEN

OBJECTIVE: To assess vitamin B(12) status in a large sample of hospitalized, inner-city older adults from nursing homes and communities with low socioeconomic status. To determine additionally if hypoalbuminemia can help identify older subjects who are at risk for vitamin B(12) deficiency. DESIGN: A cross-sectional study of hospitalized, inner-city older residents. SETTING: Acute Care Geriatrics Division, a 75-bed inpatient care service at Our Lady of Mercy Medical Center (OLMMC), a University Affiliate of New York Medical College. PARTICIPANTS: A total of 466 older patients (aged 65 to 102 years) from the community (n = 374) and nursing homes (n = 92) who were admitted to the acute care geriatrics division from 1993 to 1996. MEASUREMENTS: Patients admitted to the hospital had serum vitamin B(12) and albumin levels determined along with other nutritional parameters, routine blood tests, and physical examinations. RESULTS: On admission, 19% of hospitalized subjects had marginal serum B(12) levels (200-350 pg/mL) and 6% had low serum B(12) levels (<200 pg/mL). Mean serum B(12) levels did not differ significantly between patients from nursing homes and those from the community. Sixty-four percent 64% of all patients had low serum albumin levels (alb < 3.5 g/dL), with patients from nursing homes showing significantly lower mean serum albumin than patients admitted from the community (P <.000). We observed no positive correlation between serum albumin and serum vitamin B(12) in our older hospitalized patients from either nursing homes or community. CONCLUSIONS: In this sample of hospitalized older adults, 24% were found to have marginal or low serum B(12) status. Thus, we believe that periodic determinations of serum B(12) would be a useful addition to the general health and nutritional assessment in this age group. Our findings also suggest that hypoalbuminemia is not helpful as a predictor of low B(12) status in older hospitalized persons.

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