Brain Α-Tocopherol Concentration is Inversely Associated with Neurofibrillary Tangle Counts in Brain Regions Affected in Earlier Braak Stages: A Cross-Sectional Finding in the Oldest Old.

Objectives: Higher vitamin E status has been associated with lower risk of Alzheimer's disease (AD). However, evidence of the association of vitamin E concentration in neural tissue with AD pathologies is limited. Design: The cross-sectional relationship between the human brain concentrations of α- and γ-tocopherol and the severity of AD pathologies - neurofibrillary tangle (NFT) and neuritic plaque (NP) - was investigated. Setting & Participants: Brains from 43 centenarians (≥ 98 years at death) enrolled in the Phase III of the Georgia Centenarian Study were collected at autopsy. Measurements: Brain α- and γ-tocopherol concentrations (previously reported) were averaged from frontal, temporal, and occipital cortices. NP and NFT counts (previously reported) were assessed in frontal, temporal, parietal, entorhinal cortices, amygdala, hippocampus, and subiculum. NFT topological progression was assessed using Braak staging. Multiple linear regression was performed to assess the relationship between tocopherol concentrations and NP or NFT counts, with and without adjustment for covariates. Results: Brain α-tocopherol concentrations were inversely associated with NFT but not NP counts in amygdala (ß = -2.67, 95% CI [-4.57, -0.79]), entorhinal cortex (ß = -2.01, 95% CI [-3.72, -0.30]), hippocampus (ß = -2.23, 95% CI [-3.82, -0.64]), and subiculum (ß = -2.52, 95% CI [-4.42, -0.62]) where NFT present earlier in its topological progression, but not in neocortices. Subjects with Braak III-IV had lower α-tocopherol (median = 69,622 pmol/g, IQR = 54,389-72,155 pmol/g) than those with Braak I-II (median = 72,108 pmol/g, IQR = 64,056-82,430 pmol/g), but the difference was of borderline significance (p = 0.063). γ-Tocopherol concentrations were not associated with either NFT or NP counts in any brain regions assessed. Conclusions: Higher brain α-tocopherol level is specifically associated with lower NFT counts in brain structures affected in earlier Braak stages. Our findings emphasize the possible importance of α-tocopherol intervention timing in tauopathy progression and warrant future clinical trials.

Cancer Survivorship Program: Implementation for Individuals With Recurrent Breast Cancer.

BACKGROUND: Patients are living longer with recurrent breast cancer, but survivorship programs for these individuals are lacking. OBJECTIVES: The aims were to implement a survivorship program for individuals with recurrent breast cancer, increase their quality of life (QOL), and evaluate patient satisfaction with the program. METHODS: Survivors were referred for a one-hour coaching intervention tailored to their needs based on results of the Functional Assessment of Cancer Therapy-Breast (FACT-B) survey. Satisfaction was assessed immediately and two weeks postintervention. A paired t test was used to evaluate QOL scores before and two weeks following participation. FINDINGS: Statistically significant (p = 0.000) improvements were observed overall and in each subscale of the FACT-B survey. Patient satisfaction was high immediately postintervention and remained high at the two-week assessment.

Percutaneous fluoroscopically-guided transcervical retrograde access facilitates successful thoracic duct embolization after failed antegrade transabdominal access.

The purpose of this study was to demonstrate the feasibility of percutaneous fluoroscopically-guided transcervical retrograde access into the thoracic duct following unsuccessful transabdominal cisterna chyli cannulation to perform thoracic duct embolization for the treatment of chylothorax. Five patients, including three (60%) women and two (40%) men, with median age of 62 years, underwent percutaneous transcervical thoracic duct access and embolization after failed transabdominal cisterna chyli cannulation for the treatment of chylothorax. In all patients, fluoroscopically-guided percutaneous transcervical retrograde access into the distal thoracic duct was achieved using a 21-gauge needle and an 0.018-inch wire. Following advancement of a microcatheter, retrograde lymphangiography was performed to identify the location of thoracic duct injury. A combination of 2:1 ethiodized oil to cyanoacrylate mixtures, platinum microcoils, or stent-grafts were used to treat the chylous leaks. Technical successes, procedure durations, fluoroscopy times, blood losses, immediate adverse events, clinical successes, and follow-up durations were recorded. Technical success was defined as cannulation of the distal thoracic duct using a transcervical approach followed by treatment of the thoracic duct injury. Adverse events were classified according to the Society of Interventional Radiology guidelines. Clinical success was defined as resolution of the presenting chylothorax. Percutaneous transcervical retrograde thoracic duct access and treatment was technically successful in all patients (n=5). Median procedure duration was 173 minutes (range: 136-347 minutes) with a median fluoroscopy time of 94.7 minutes (range: 47-125 minutes). Median blood loss was 10 mL (range: 5-20 mL). No minor or major adverse occurred. Clinical success was achieved in all patients (n=5). Median follow-up was 372 days (range: 67-661 days). Percutaneous fluoroscopically- guided transcervical retrograde thoracic duct access is an effective and safe method to perform thoracic duct embolization following unsuccessful transabdominal cisterna chyli cannulation for the treatment of chylothorax.

Asymmetric discounting in intertemporal choice: a query-theory account.

People are impatient and discount future rewards more when they are asked to delay consumption than when they are offered the chance to accelerate consumption. The three experiments reported here provide a process-level account for this asymmetry, with implications for designing decision environments that promote less impulsivity. In Experiment 1, a thought-listing procedure showed that people decompose discount valuation into two queries. Whether one considers delayed or accelerated receipt of a gift certificate influences the order in which memory is queried to support immediate versus delayed consumption, and the order of queries affects the relative number of patient versus impatient thoughts. Relative frequency and clustering of impatient thoughts predicts discounting and mediates the discounting asymmetry. Experiment 2 implicated query order causally: When participants listed reasons for immediate versus delayed consumption in the order used spontaneously in acceleration and delay decisions, the discounting asymmetry was replicated; reversing the order in which reasons were listed eliminated the asymmetry. The results of Experiment 3, which used an implicit-memory task, support a memory-interference account of the effect of query order.

Neuromuscular fatigue and potentiation following two successive high intensity resistance exercise sessions.

Resistance exercise can result in both potentiating and fatiguing responses. These responses can acutely affect performance, which may affect subsequent exercise sessions in the same day. The purpose of this investigation was to study the acute neuromuscular responses to two high intensity training sessions in the same day. Twelve recreationally trained males performed two training sessions, each involving ten sets of five repetitions in the speed squat exercise. For the initial session (HIT-1), the barbell load was constant at 70% one repetition maximum, whereas during the second session (HIT-2), barbell load decreased if movement velocity decreased. Neuromuscular performance testing consisted of unilateral isometric knee extensor actions performed prior to the training day (PRE) and following each testing session. Prior to the sessions, subjects provided a muscle biopsy for myosin heavy chain analysis. Peak force was impaired 16.9 (9.5)% (P approximately 0.00; d=1.62) following HIT-1 and 19.9 (18.4)% (P approximately 0.00; d=1.94) following HIT-2. Initial rate of force development was depressed from PRE following HIT-1 (P approximately 0.00; d=1.74) and HIT-2 (P approximately 0.00; d=2.18); however, this was dependent on muscle fiber composition. Significant correlations existed between the change score for initial rate of force development from HIT-1 to HIT-2 and myosin heavy chain I (r= -0.60; P=0.04) and IIa (r=0.69; P=0.01) expression. Impaired neuromuscular performance following HIT-1 may occur due to low frequency fatigue. For individuals with predominantly myosin heavy chain IIa, HIT-2 appeared to induce post-activation potentiation, resulting in restoration of the initial rate of force development.

Reiter syndrome following protracted symptoms of Cyclospora infection.

Two large outbreaks of diarrheal illness associated with Cyclospora cayetanensis, a coccidian parasite, provided an opportunity to evaluate clinical syndromes associated with this enteric pathogen. Reiter syndrome, a triad of ocular inflammation, inflammatory oligoarthritis, and sterile urethritis, has been associated with enteric infections. We describe the first case of Reiter syndrome following protracted symptoms of Cyclospora infection.

Achievable standards, benchmarks for reporting, and criteria for evaluating cervical cytopathology. Second edition including revised performance indicators.

Endocervical cells are not essential for an adequate smear, except where the previous abnormality was seen in endocervical cells. When three consecutive smears are reported as inadequate, the recommendation for colposcopy should be made at the discretion of the pathologist in the light of a review of the relevant slides and the clinical history of the woman concerned. The cellularity of previous sequential smears should not be combined in order to judge the present smear test as negative. There should be no more than three abnormal smears (including borderline) over any 10-year period without a recommendation for colposcopy. At least three negative smears, at least 6 months apart, should be reported before a woman is returned to routine recall following a smear showing mild dyskaryosis or borderline nuclear change. There is no evidence that demonstrates that selective double screening is any more effective in preventing false-negatives than rapid review and this practice cannot therefore be justified. Sensitivity should be based on all abnormalities detected on primary screening rather than on moderate dyskaryosis or worse. Ranges for reporting rates are based on the 10-90th percentiles of the range for laboratories reporting over 10000 screening smears per year in KC61 returns, but apply to all laboratories reporting screening smears.

Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density.

BACKGROUND: Lutein and zeaxanthin are the only carotenoids in the macular region of the retina (referred to as macular pigment [MP]). Foods that are rich in lutein and zeaxanthin can increase MP density. Response to dietary lutein and zeaxanthin in other tissues has not been studied. OBJECTIVE: The objective of this study was to examine tissue responses to dietary lutein and zeaxanthin and relations among tissues in lutein and zeaxanthin concentrations. DESIGN: Seven subjects consumed spinach and corn, which contain lutein and zeaxanthin, with their daily diets for 15 wk. At 0, 4, 8, and 15 wk and 2 mo after the study, serum, buccal mucosa cells, and adipose tissue were analyzed for carotenoids, and MP density was measured. RESULTS: Serum and buccal cell concentrations of lutein increased significantly from baseline during dietary modification. Serum zeaxanthin concentrations were greater than at baseline only at 4 wk, whereas buccal cell and adipose tissue concentrations of zeaxanthin did not change. Adipose tissue lutein concentrations peaked at 8 wk. Changes in adipose tissue lutein concentration were inversely related to the changes in MP density, suggesting an interaction between adipose tissue and retina in lutein metabolism. To investigate the possibility of tissue interactions, we examined cross-sectional relations among serum, tissue, and dietary lutein concentrations, anthropometric measures, and MP density in healthy adults. Significant negative correlations were found between adipose tissue lutein concentrations and MP for women, but a significant positive relation was found for men. CONCLUSION: Sex differences in lutein metabolism may be an important factor in tissue interactions and in determining MP density.

Risk factors for HIV-1 shedding in semen.

Semen is the body fluid most commonly associated with sexual transmission of human immunodeficiency virus type-1 (HIV-1). Because the male genitourinary tract is distinct immunologically from blood, compartment-dependent factors may determine HIV-1 shedding in semen. To identify these factors, the authors obtained 411 semen and blood specimens from 149 men seen up to three times. Seminal plasma was assayed for HIV-1 RNA and semen was cocultured for HIV-1 and cytomegalovirus (CMV), which may up-regulate HIV-1 replication. The best multivariate model for predicting a positive semen HIV-1 coculture included two local urogenital factors, increased seminal polymorphonuclear cell count (odds ratio (OR) = 12.6 for each log10 increase/mL, 95% confidence interval (CI) 12.2, 134.5) and a positive CMV coculture (OR = 3.0, 95% CI 1.2, 7.7). The best multivariate model for predicting semen HIV-1 RNA included two systemic host factors, CD4+ cell counts <200/microliter (OR = 3.0, 95 percent CI 1.3, 6.9) and nucleoside antiretroviral therapy (monotherapy: OR = 0.5, 95% CI 0.3, 1.0; combination therapy: OR = 0.4, 95% CI 0.2, 0.9), and a positive CMV coculture (OR = 1.7, 95% CI 1.0, 3.0). Thus, both systemic and local genitourinary tract factors influence the risk of semen HIV-1 shedding. These findings suggest that measures of systemic virus burden alone may not predict semen infectivity reliably.

alpha-Tocopherol concentrations in plasma but not in lipoproteins fluctuate during the menstrual cycle in healthy premenopausal women.

Because premenopausal women experience cyclic fluctuations of plasma carotenoids and their lipoprotein carriers, it was hypothesized that plasma alpha-tocopherol (A-T) fluctuates by phase of the menstrual cycle. Twelve free-living women, with a confirmed ovulatory cycle, were given a controlled diet for two consecutive menstrual cycles. Blood was drawn during the menses, early follicular, late follicular and luteal phases to simultaneously measure serum hormones, plasma lipoproteins and A-T concentrations, and A-T distribution in the lipoprotein fractions. Plasma A-T concentrations were significantly lower during menses than during the luteal phase by approximately 12% in each controlled diet cycle (P < 0.001). Adjustment for serum cholesterol and triglyceride concentrations did not alter these findings. The distributions of A-T in lipoprotein cholesterol fractions were not significantly different by menstrual phase. From 61 to 62% of A-T was concentrated in the LDL fraction, with another 9-14% in HDL2, 17-22% in HDL3 and the remaining 6-8% in VLDL+ IDL. There were no significant differences in lipoprotein cholesterol fractions by menstrual phase, except for a significant increase (P = 0.03) in HDL2 cholesterol from the early follicular to the late follicular phase. Spearman rank correlations from data during the second controlled diet month showed A-T in HDL2 in the late follicular phase was positively correlated with HDL cholesterol in the early follicular (r = 0.88), late follicular (r = 0.86) and luteal phases (r = 0.86) and with luteal apolipoprotein (ApoA-1) level (r = 0.90), and luteal HDL2 cholesterol (r = 0.83). A-T in HDL3 in the early follicular phase was negatively correlated with HDL2 cholesterol (r = -0.96) and ApoA-1 (r = -0.85), whereas luteal A-T in HDL3 was correlated with luteal HDL3 cholesterol (r = -0.79). Late follicular A-T in VLDL was positively correlated with early follicular HDL3 cholesterol and late follicular HDL3 cholesterol (r = 0.83). Fluctuations of A-T concentrations by phase of the menstrual cycle should be taken into consideration in future research concerning premenopausal women and the risk of chronic disease.

Effect of menstrual cycle phase on the concentration of individual carotenoids in lipoproteins of premenopausal women: a controlled dietary study.

Because premenopausal women experience cyclic fluctuations of plasma carotenoids and their lipoprotein carriers, it is hypothesized that carotenoid concentrations in lipoprotein fractions fluctuate by phase of the menstrual cycle. Nine women ate a standard set of carotenoid-rich foods daily for two cycles under isoenergetic conditions. In the second cycle, hormones and carotenoids in lipoprotein fractions were measured in the early and late follicular and luteal phases. alpha-Carotene concentrations in the LDL fraction were lower in the early than in the late follicular phase (P = 0.03) on the basis of regression analysis. beta-carotene concentrations in the LDL fraction and the HDL2 subfraction were higher in the late follicular than in the luteal phase (P = 0.02 and P = 0.04, respectively). Lutein/zeaxanthin concentrations in the LDL and HDL fractions were higher in the late follicular than in the luteal phase (P = 0.03 and P = 0.02, respectively). In each phase, 80% of alpha-carotene, 82% of beta-carotene, 85% of lycopene, and 64% of lutein/zeaxanthin were distributed in the LDL fraction. Among the hydrocarbon cartenoids, 18% of alpha-carotene and of beta-carotene and 13% of lycopene were distributed in the HDL fraction, with slightly more in the HDL2 than in the HDL3 subfraction. In contrast 34% of lutein/zeaxanthin was distributed in the HDL fraction with more concentrated in the HDL3 than in the HDL2 subfraction. Less than 4% of any carotenoid was found in the VLDL + IDL (intermediate-density-lipoprotein) fractions. Thus, the hydrocarbon carotenoids were highly concentrated in the LDL fraction and xanthophyll was more evenly distributed in the LDL and HDL fractions. The cyclic fluctuations of these carotenoids in lipoprotein fractions add another dimension to the understanding of their transport and physiologic function.

Beta-carotene isomers in human serum, breast milk and buccal mucosa cells after continuous oral doses of all-trans and 9-cis beta-carotene.

The concentrations of all-trans beta-carotene (tBC) and 9-cis beta-carotene (9cBC) isomers in serum, breast milk and buccal mucosa cells were determined after continuous oral doses as a simple, non-invasive method to determine whether differences in tissue uptake are important determinants of serum responses. Twelve healthy lactating women were recruited for a nonresidential study. On d 1, blood samples were obtained from fasting subjects for baseline concentrations of beta-carotene isomers. Over a 1-wk period, subjects were given either seven doses of a placebo (n = 4) or seven doses of naturally occurring BC (n = 8) derived from Dunaliella bardawil (64 mg tBC, 69 mg 9cBC). Subjects were instructed to consume a single beta-carotene dose along with a meal containing adequate fat each day for 1 wk. On d 2, 3, 5 and 8, blood samples and breast milk were collected from fasting subjects. On d 1 and 8, buccal mucosa cells were collected. Samples were analyzed for carotenoids by HPLC. In the experimental group, the mean serum concentration of tBC significantly increased to seven times the baseline level by the end of the supplementation period (P < 0.0001). The serum concentration of 9cBC significantly increased to three times the baseline level by the end of the supplementation period (P < 0.0001). The changes in milk and buccal mucosa cells levels of tBC and 9cBC followed a pattern similar to that for serum, showing significant increases at the end of the supplementation period. In the control group, the serum, milk and buccal mucosa cell concentrations of BC isomers did not change. This study confirms the previously reported differences in the serum response curves of tBC and 9cBC and provides evidence that there is no difference in tissue uptake of tBC and 9cBC.

Ingestion by men of a combined dose of beta-carotene and lycopene does not affect the absorption of beta-carotene but improves that of lycopene.

A double-blind study was conducted in 10 healthy men to investigate serum beta-carotene and lycopene responses after ingestion of individual and combined doses of beta-carotene (BC) and lycopene. On each dosing day, a baseline blood sample was drawn, followed by an oral dose of 0.11 mmol (60 mg) of either all-trans BC or all-trans lycopene or by a combined oral dose of 0.11 mmol each. Subjects were tested with each of the three doses. The dose type was randomized. Blood (10 mL) was drawn at 1, 3, 5, 7, 9, 12 and 24 h after dosing. At 2 and 4 wk after the first dose, the protocol was repeated with the other doses. After ingestion of the BC dose, serum BC concentrations significantly decreased from baseline at 1 and 3 h followed by a continuous increase from baseline that was significant at 12 and 24 h (P < 0.01). Serum lycopene concentrations significantly increased from baseline at 5 h after the lycopene dose (P < 0.008) and returned to baseline thereafter. Ingestion of a combined dose of BC and lycopene resulted in a significant increase in serum concentrations of both BC and lycopene at 24 h (P < 0.05). The 24-h area under the curve (AUC) for BC was not different when BC was ingested alone or with lycopene, whereas the 24-h AUC for lycopene was significantly greater when lycopene was ingested with BC than when ingested alone (P < 0.05). Our data suggest that ingestion of a combined dose of BC and lycopene has little effect on the absorption of BC but improves that of lycopene in men.

Dietary modification of human macular pigment density.

PURPOSE: The retinal carotenoids lutein (L) and zeaxanthin (Z) that form the macular pigment (MP) may help to prevent neovascular age-related macular degeneration. The purpose of this study was to determine whether MP density in the retina could be raised by increasing dietary intake of L and Z from foods. METHODS: Macular pigment was measured psychophysically for 13 subjects. Serum concentrations of L, Z, and beta-carotene were measured by high-performance liquid chromatography. Eleven subjects modified their usual daily diets by adding 60 g of spinach (10.8 mg L, 0.3 mg Z, 5 mg beta-carotene) and ten also added 150 g of corn (0.3 mg Z, 0.4 mg L); two other subjects were given only corn. Dietary modification lasted up to 15 weeks. RESULTS: For the subjects fed spinach or spinach and corn, three types of responses to dietary modification were identified: Eight "retinal responders" had increases in serum L (mean, 33%; SD, 22%) and in MP density (mean, 19%; SD, 11%); two "retinal nonresponders" showed substantial increases in serum L (mean, 31%) but not in MP density (mean, -11%); one "serum and retinal nonresponder" showed no changes in serum L, Z, or beta-carotene and no change in MP density. For the two subjects given only corn, serum L changed little (+11%, -6%), but in one subject serum Z increased (70%) and MP density increased (25%). CONCLUSIONS: Increases in MP density were obtained within 4 weeks of dietary modification for most, but not all, subjects. When MP density increased with dietary modification, it remained elevated for at least several months after resuming an unmodified diet. Augmentation of MP for both experimental and clinical investigation appears to be feasible for many persons.

Effect of pregnancy and zidovudine therapy on viral load in HIV-1-infected women.

The objective of this study was to determine the effect of pregnancy and zidovudine (ZDV) on viral load in HIV-1 infected women. A prospective nonrandomized cohort study was conducted at a university medical center and affiliated clinic and included 44 HIV-1-seropositive pregnant women seen between June 1991 and September 1995. Twenty-three women initiated ZDV therapy during their pregnancy. Seventeen women did not take antiretrovirals, and four women took ZDV prior to and throughout pregnancy. HIV-1 viral load as determined by quantitative peripheral blood mononuclear cell (PBMC) culture and quantitative plasma RNA levels was measured at various times during pregnancy and in the postpartum period. HIV-1 load, by both infectivity and RNA levels, was relatively low and remained stable during pregnancy and through 6 weeks post partum. Initiation of ZDV therapy during pregnancy did not result in a significant decrease in viral load at delivery when controlling for the effect of pregnancy. In those women who received ZDV therapy only during pregnancy, there was a trend toward an increase in viral load measured by PBMC infectivity 6 months post partum compared with the levels before the initiation of ZDV. Mother-to-child transmission of HIV-1 occurred in one of 27 (4%) ZDV-treated women and in two of 16 (12.5%) untreated women. Among HIV-1-infected pregnant women with low viral levels, HIV-1 plasma RNA and infectivity remained stable during and after gestation. Although these results are based on a relatively small number of women and should be considered preliminary, the lack of significant ZDV-associated diminution in viral levels suggests that the protective effect of ZDV on the mother-to-child transmission of HIV-1 may not be due to the reduction in maternal viral levels but, by inference, may be due to the prevention of HIV-1 reverse transcription in the newborn.

Serum response of all-trans and 9-cis isomers of beta-carotene in humans.

OBJECTIVE: Little work has been performed on the serum response of various carotene isomers. The present study was carried out to examine the serum response of all-trans and 9-cis isomers of beta-carotene (BC) using frequent blood sample collections at early time points. METHODS: Serum responses of all-trans BC and a mixture of BC isomers containing 80% 9-cis BC were studied in 15 men by measuring the serum concentrations of BC at 1, 3, 5, 7, 9, 12, and 24 hours after a single large oral dose of all-trans BC or 9-cis BC. RESULTS: The serum response to an oral dose of all-trans BC (120 mg) significantly increased from baseline at 24 hr (p < 0.004). After an oral dose of a mixture of BC isomers (120 mg, 80% 9-cis BC), the peak concentration of 9-cis BC was significantly greater that baseline values (p < 0.016). CONCLUSIONS: Increases in serum all-trans BC levels, in part, may be due to greater intestinal absorption, whereas the inability to measure a significant increase in the concentration of 9-cis BC may indicate poor absorption, isomerization to all-trans BC, or a very rapid tissue uptake.

Molecular definition of a narrow interval at 7q22.1 associated with myelodysplasia.

Chromosome 7 translocations, deletions, or monosomy are associated with myelodysplasia (MDS) and acute myeloid leukemia both in children and adults. These chromosomal anomalies represent one of the most common cytogenetic abnormalities associated with these diseases and usually herald a poor prognosis. In this study two cosmid DNA probes that mapped to 7q22.1 and were known to be separated by approximately 500 kb were identified to flank the proximal inversion breakpoint in a patient carrying a constitutional inversion (7q22.1-34) associated with MDS. A yeast artificial chromosome (YAC) clone that encompassed the two cosmids was identified and shown to span the breakpoint. Fluorescence in situ hybridization was then used to analyze six additional patients with myelodysplasia and chromosomal rearrangements of the 7q22 region (three patients had translocations and three carried deletions). The breakpoint in one of the patients was found to be contained within the same YAC clone that spanned the inversion breakpoint. Moreover, this same interval was determined to be absent in all three patients with chromosomal deletions. These results suggest that this segment of DNA on chromosome 7q22.1 may contain specific gene(s) that have a significant role in myeloid malignancies.

Relation between beta-carotene intake and plasma and adipose tissue concentrations of carotenoids and retinoids.

We evaluated the relation between beta-carotene intake and plasma and adipose tissue concentrations of carotenoids and retinoids. In Study 1, beta-carotene intakes were significantly greater in vegetarians than in nonvegetarians. Plasma concentrations of beta-carotene were also significantly higher in vegetarians than in nonvegetarians but only after two nonvegetarians with excessive intake of carrots were omitted. Plasma retinoid (retinol, retinyl esters, and retinoic acid) concentrations were not different between the two groups. In Study 2, female subjects ingested a daily placebo or 90 mg beta-carotene for 3 wk. In the group fed beta-carotene, plasma beta-carotene concentrations were significantly increased from baseline at 1, 2, and 3 wk. No beta-carotene changes were observed in the placebo-fed group. Plasma retinoid concentrations did not change in either group. In Study 3, adipose tissue beta-carotene and retinoid concentrations were measured in men after an oral beta-carotene dose (120 mg, experimental subjects) or no beta-carotene (control subjects). In the experimental subjects, adipose beta-carotene concentrations increased from baseline at 5 and 10 d postdosing. The control group's adipose tissue beta-carotene concentration did not change over a 10-d period. Changes in retinoids in adipose tissue were not significant in either group. In conclusion, dietary and supplemental beta-carotene increased plasma beta-carotene concentrations but had no effect on plasma retinoid concentrations. There may be little tissue metabolism of beta-carotene to retinoids. Therefore, the anticarcinogenic effect of beta-carotene, if any, may be due to properties of the molecule itself.