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 (β = -2.67, 95% CI [-4.57, -0.79]), entorhinal cortex (β = -2.01, 95% CI [-3.72, -0.30]), hippocampus (β = -2.23, 95% CI [-3.82, -0.64]), and subiculum (β = -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.

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.

Premature Arterial Disease Associated with Familial Antithrombin III Deficiency

Antithrombin III (ATIII) deficiency is one of the few known abnormalities of the coagulation system known to predispose to venous thromboembolism but its relation to arterial disease is not established. We describe two related patients with this disorder, both of whom suffered arterial thrombotic events, at an early age. Both patients had other potential risk factors, though these would normally be considered unlikely to lead to such catastrophic events at such an age. Thrombosis due to ATIII deficiency is potentially preventable, and this diagnosis should be sought more frequently in patients with arterial thromboembolism, particularly if occurring at a young age. In addition, in patients with known ATIII deficiency, other risk factors for arterial disease should be eliminated, if possible. In particular, these patients should be counselled against smoking.

Preservation of platelet function in cryopreserved platelet concentrates with prostacyclin

Prostacyclin (Epoprostenol) or a stable prostacyclin analogue (ZK 36,374) were added to platelet concentrates prior to cryopreservation. This resulted in significantly better preserved function of the thawed platelet concentrate, assessed by platelet aggregation to various concentrations of ADP, collagen and ristocetin, compared to control cryopreserved platelet concentrates. The use of prostacyclin or one of its stable analogues should be considered to reduce platelet activation and subsequent loss of function during the various manipulative procedures when preparing standard and cryopreserved platelet concentrates.

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.

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.

Anchoring, Activation, and the Construction of Values

Anchoring is a pervasive judgment bias in which decision makers are systematically influenced by random and uninformative starting points. While anchors have been shown to affect a broad range of judgments including answers to knowledge questions, monetary evaluations, and social judgments, the underlying causes of anchoring have been explored only recently. We suggest that anchors affect judgments by increasing the availability and construction of features that the anchor and target hold in common and reducing the availability of features of the target that differ from the anchor. We test this notion of anchoring as activation in five experiments that examine the effects of several experimental manipulations on judgments of value and belief as well as on measures of cognitive processes. Our results indicate that prompting subjects to consider features of the item that are different from the anchor reduces anchoring, while increasing consideration of similar features has no effect. The anchoring-as-activation approach provides a mechanism for debiasing anchoring and also points to a common mechanism underlying anchoring and a number of other judgment phenomena. Copyright 1999 Academic Press.

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.

Biological studies of soils in paired old and new land sites growing sugarcane

Summary. The growth of sugarcane in soils from land monocultured with sugarcane, and from land which had either never been cropped with sugarcane, or just recently cropped, was compared under glasshouse conditions. In general, cane growth in new land soils was greater than in monocultured soil (shoot growth 7.4%, root growth 21.4%). Responses to soil pasteurisation were investigated in some soils and were greater in monocultured soils suggesting that root growth constraints were larger in the monocultured soil (210% response in monocultured soils v. 64% in new land soils). Assays for sugarcane root pathogens suggested that Pachymetra chaunorhiza was a major contributor to the old/new land growth responses, but it is unlikely that Pythium spp. were factors in the growth differences. Monitoring of other groups of organisms in soil from one site suggested that sugarcane monoculture may affect populations in the broader biological community.

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.

Discrimination in absorption or transport of beta-carotene isomers after oral supplementation with either all-trans- or 9-cis-beta-carotene

Human subjects (n = 24) were supplemented with 100 mg beta-carotene/d for 6 d, either as synthetic all-trans-beta-carotene or a natural beta-carotene preparation derived from the alga Dunaliella salina, which consists of a 50:50 mixture of all-trans- and 6-cis-beta-carotene. This loading dose was followed by a 23-d maintenance dose consisting of alternate-day supplementation with 50 mg all-trans-beta-carotene or either 66 or 100 mg of the natural 50:50 isomeric mixture. The loading dose resulted in significant increases in plasma concentrations of both isomers, with the all-trans-beta-carotene-supplemented group showing a 7.2- and 5.0-fold increase in the all-trans and 9-cis concentrations in plasma, respectively. The group receiving the 50:50 mixture showed a 4.0- and 3.7-fold increase in the all-trans and 9-cis concentrations in plasma, respectively, without any apparent dose-dependency. However, even with the 50:50 mixture, the 9-cis concentrations were only a small fraction of the total plasma beta-carotene. Results after an additional 23-d period of alternate-day supplementation were not significantly different from those described above for the 6-d supplementation. Increases in low-density-lipoprotein concentrations of total beta-carotene correlated strongly with the increases seen in plasma concentrations. Lipid-soluble antioxidants vitamin E and ubiquinol were unaffected by beta-carotene supplementation. However, the amount of lycopene in the low-density lipoprotein decreased during this supplementation period. A strong discrimination between these two geometric isomers of beta-carotene was demonstrated, although the tissue site of discrimination was not determined.

Intestinal absorption and metabolism of 9-cis-beta-carotene in vivo: biosynthesis of 9-cis-retinoic acid

This study was done to examine the intestinal absorption and cleavage of 9-cis-beta-carotene in vivo. A micellar solution, containing either no addition or 10 mumol of 9-cis- or all-trans-beta-carotene, was perfused for 2 h through the upper portion of the small intestine of ferrets. The effluent of a mesenteric lymph duct cannulation was collected, as well as intestinal mucosa scrapings, a portal blood sample, and a liver biopsy, both before and after perfusion. Carotenoids and retinoids were measured by reverse-phase, high performance liquid chromatography. 9-Cis- and all-trans-beta-carotene were transported equally well into mesenteric lymph, although the intestinal concentration of the corresponding isomer was tenfold higher after perfusion of the 9-cis- isomer than after perfusion of all-trans-beta-carotene. Regardless of which isomer was used, perfusion of beta-carotene resulted in the biosynthesis of similar amounts of retinoic acid in portal blood, liver, and intestine. However, after the perfusion of all-trans-beta-carotene, all the retinoic acid formed was in the all-trans- form, whereas the perfusion of 9-cis-beta-carotene resulted in the biosynthesis of about 50% of the total retinoic acid as the 9-cis-isomer. We conclude that in the in vivo ferret model, 9-cis-beta-carotene has a good bioavailability and is a precursor of 9-cis-retinoic acid.

HIV retrotransposon activity and the immunopathogenesis of AIDS

This article presents the new hypothesis that HIV retrotransposon insertional mutagenesis induces genomic effects that bring about immune dysfunction through disruption, deletion or rearrangement of the genome of the host. This activity may be augmented by the action of most, if not all, the cofactors of HIV-induced disease.

Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation

The inhibition of low density lipoprotein (LDL) oxidation has been postulated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Available data on the ability of beta-carotene to inhibit LDL oxidation are conflicting. We examined the role of in vivo and in vitro supplementation with beta-carotene on metal ion-dependent (cupric ions, Cu2+) and metal ion-independent (2,2'-azobis[2-amidinopropane]dihydrochloride, AAPH) oxidation of LDL as measured by the formation of conjugated dienes (absorbance at 234 nm). Sixteen subjects were supplemented with 50-100 mg of beta-carotene on alternate days for 3 weeks following a week-long loading dose of 100 mg/day. Plasma beta-carotene levels rose 5.5-fold, while LDL beta-carotene levels rose 8.5-fold. Oxidation of LDL by Cu2+ or AAPH was not significantly delayed after in vivo supplementation with beta-carotene compared with baseline. For AAPH, the lag phase (in minutes) was 75 +/- 8 at baseline and 83 +/- 14 after supplementation (P = 0.07). For Cu2+, the lag phase was 172 +/- 41 at baseline and decreased to 130 +/- 24 after supplementation (P < 0.01). Similarly, no protective effect against Cu(2+)-induced oxidation was observed when beta-carotene was added to LDL in vitro. Supplementation of plasma with beta-carotene in vitro prior to LDL isolation also did not enhance LDL's resistance to Cu(2+)- or AAPH-induced oxidation, despite a 5-fold increase in LDL beta-carotene levels over vehicle control.(ABSTRACT TRUNCATED AT 250 WORDS)

Directed evolution of biosynthetic pathways. Recruitment of cysteine thioethers for constructing the cell wall of Escherichia coli

We report that expansion of thioether biosynthesis in Escherichia coli generates sulfur-containing amino acids that can replace meso-diaminopimelate, the essential amino acid used for cross-linking the cell wall. This was accomplished by jointly overexpressing the metB gene coding for L-cystathionine gamma-synthase and disrupting the metC gene, whose product, L-cystathionine beta-lyase, is responsible for the destruction of L-cystathionine and other L-cysteine thioethers. As a result, meso-lanthionine and L-allo-cystathionine were produced endogenously and incorporated in the peptidoglycan, thereby enabling E. coli strains auxotrophic for diaminopimelate to grow in its absence. Thus, current techniques of metabolic engineering can be applied to evolving the chemical constitution of living cells beyond its present state.

Contribution of apoB-48 and apoB-100 triglyceride-rich lipoproteins (TRL) to postprandial increases in the plasma concentration of TRL triglycerides and retinyl esters

After the ingestion of a fat-rich meal, there is a postprandial increase in the plasma concentration of both apolipoprotein B-48- and apoB-100-containing triglyceride-rich lipoproteins (apoB-48 and apoB-100 TRL). In order to determine the contribution of these lipoproteins to postprandial lipemia, the concentration of triglycerides (TG) and retinyl esters (RE) was measured in apoB-48 and apoB-100 TRL after an oral fat load. Six normolipidemic male subjects were fed heavy cream (1 g fat per kg body weight) containing vitamin A (3000 retinol equivalents). TRL were isolated by ultracentrifugation from plasma samples obtained at regular intervals after the meal, and apoB-100 TRL were separated from apoB-48 TRL by affinity chromatography using monoclonal antibodies. Postprandial increase in plasma TG concentration was due to an increase in TG in the TRL fraction, which in turn was predominantly (82 +/- 4%) due to an increase in TG in apoB-48 TRL. Contribution of apoB-100 TRL to postprandial increase in TRL TG was 3-27% in individual subjects. ApoB-100 TRL remained a significant carrier of total plasma triglyceride in the fed state, as reflected by similar apoB-100 and apoB-48 TRL TG concentrations at 2, 4, and 6 h after the fat meal. Retinyl esters were regularly detected in apoB-100 TRL. Seventy-five (+/- 9) percent of the increase in TRL-RE was due to RE in apoB-48 TRL and 25 +/- 9% was due to RE in apoB-100. These data suggest that RE in plasma are not always associated with apoB-48-containing lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of an effect of multivitamins containing vitamin A on serum retinyl esters and liver function tests in healthy women

Two hundred eighty-four female adults (aged 40-70 years) were longitudinally studied to investigate the relationship between dietary supplemental vitamin A and serum biochemical markers of vitamin A toxicity. Serum retinol, retinyl esters, and retinol-binding protein (RBP), alkaline phosphatase and aspartate aminotransferase activities and bile acids were measured at baseline, 1 and 2 years. Fasting serum retinol and retinyl ester concentrations were determined by high-performance liquid chromatography, and dietary and supplemental intake of vitamin A were assessed by 3-day food records. There was no difference in dietary vitamin A intake between supplement users and nonusers. In supplemental users, the mean +/- SEM supplemental vitamin A intake was 952 +/- 81 IU/day (range 250-5000 retinol equivalents/day). Serum retinol, retinyl esters, and RBP concentrations were not different between the two groups during the 2-year period. For each group, serum retinyl esters significantly increased over time (p < 0.03), but the magnitude of the increase was not different between the groups. Serum levels of retinol, retinyl esters, and RBP were not correlated with vitamin A intake or age in either group. Biochemical measures of liver damage (serum alkaline phosphatase and aspartate aminotransferase activities and serum bile acids) were not related to serum retinol, retinyl esters or RBP concentrations, nor were they different between nonusers and users of supplemental vitamin A. This study provides evidence that long-term supplemental vitamin A in doses commonly found in multivitamin supplements does not present a risk for hypervitaminosis A.

Sex differences in postabsorptive plasma vitamin A transport

This study examined postabsorptive plasma vitamin A after doses of retinyl palmitate in healthy men (n = 28) and women (n = 31). On consecutive days one physiologic [3000 retinol equivalents (RE)] and one pharmacologic dose (105,000 RE) were administered and blood samples collected. Plasma retinol and retinyl esters were measured by HPLC. Tolerance curves were constructed by plotting plasma retinyl ester concentration vs time. Postprandial retinyl ester response was measured as peak rise in retinyl ester concentration and area under the curve (AUC). Peak plasma retinyl ester concentration occurred earlier for females but the earlier peak was significant only for younger subjects (< or = 50 y, P < 0.02) given the low dose and older subjects (> 50 y, P < 0.02) given the high dose. Peak rise and AUC were lower in females than in males, but this difference was significant for the high dose only (P < 0.05). In the high-dose experiment, when each age group was evaluated for sex differences the peak rise was significantly greater in males than in females in the older subjects (P < 0.05). Postabsorptive plasma retinol did not change from fasting concentrations. A lower plasma response in retinyl esters in women could be due to a more efficient chylomicron-remnant clearance.

Distribution of orally administered beta-carotene among lipoproteins in healthy men

Plasma and lipoprotein concentrations of beta-carotene (BC) were measured in men for 10 d after an oral dose of BC (120 mg) (experimental subjects, n = 11) or no BC (control subjects, n = 5). Lipoproteins were separated by sequential ultracentrifugation and BC was measured by HPLC. Plasma and lipoprotein BC concentrations in control subjects were steady. In experimental subjects, plasma BC content increased by 6 h postdosing (P less than 0.015), peaked at 24 h (P less than 0.05), and returned to baseline by 7 d. Maintenance of plasma BC concentrations suggests homeostatic control. Of the 11 experimental subjects, only 4 had a plasma response. Early increases in the BC content of chylomicrons, very-low-density lipoproteins, and intermediate-density lipoproteins. Intestinal input accounts for early rises in circulating BC concentrations whereas hepatic secretion is the source of later increases. Among all of the lipoproteins, transfer of BC may occur.

Evaluation of vitamin A absorption by using oil-soluble and water-miscible vitamin A preparations in normal adults and in patients with gastrointestinal disease

We evaluated vitamin A absorption in 50 healthy adults and 26 gastrointestinal-disease patients by measuring the postabsorptive response in plasma retinyl esters after oral doses of the vitamin. On 3 consecutive days, two physiologic-dose tests of 2000-2400 retinol equivalents (RE) and one pharmacologic-dose test (84,000 RE) were administered. The physiologic doses were given as an oil-soluble or a water-miscible preparation. In gastrointestinal-disease patients the physiologic-dose test was highly correlated with the pharmacologic-dose test for the oil-soluble preparation as determined by peak rise (r = 0.50, P less than 0.05) and area under the curve (r = 0.56, P less than 0.01), suggesting that the physiologic dose is valid for investigating vitamin A absorption. Intestinal-disease or resection patients absorbed preparations poorly. Pancreatic-disease patients absorbed the oil-soluble preparation poorly. Physiologic rather than pharmacologic doses of vitamin A can be used to study vitamin A absorption.

Reduced absorption of oral ciprofloxacin after chemotherapy for haematological malignancy

Six patients with newly diagnosed haematological malignancy were treated with ciprofloxacin 500 mg orally, as chemoprophylaxis during neutropenia. The mean serum ciprofloxacin concentrations, measured 1, 2, 3 and 4 h after dosage were reduced for up to ten days after the start of chemotherapy. The mean maximum serum concentration and AUC 0-4 h were reduced from 3.7 (95% confidence limits, 2.3-5.1) mg/l and 10.7 (6.2-15.2) mg/l.h pre-chemotherapy to 2.0 (1.4-2.6) mg/l and 5.7 (4.4-7.0) mg/l.h, 13 days after chemotherapy. Absorption of ciprofloxacin is reduced after cytotoxic chemotherapy, and this may have implications for the use of oral ciprofloxacin in this group of patients.

Premature arterial disease associated with familial antithrombin III deficiency

Antithrombin III (ATIII) deficiency is one of the few known abnormalities of the coagulation system known to predispose to venous thromboembolism but its relation to arterial disease is not established. We describe two related patients with this disorder, both of whom suffered arterial thrombotic events, at an early age. Both patients had other potential risk factors, though these would normally be considered unlikely to lead to such catastrophic events at such an age. Thrombosis due to ATIII deficiency is potentially preventable, and this diagnosis should be sought more frequently in patients with arterial thromboembolism, particularly if occurring at a young age. In addition, in patients with known ATIII deficiency, other risk factors for arterial disease should be eliminated, if possible. In particular, these patients should be counselled against smoking.

The validity of verbal protocols

The reactivity of a "think aloud" verbal protocol and the veridicality of different retrospective protocols were tested over four dissimilar tasks. Generating a concurrent protocol altered accuracy in two tasks, simple addition and a choice between two gambles, and generally prolonged response times. Such reactivity partially qualifies the dominant theory of protocol generation (Ericsson & Simon, 1984). Retrospective protocols yielded substantial forgetting or fabrication in all tasks, supporting the consensus on the nonveridicality of these methods. It is concluded that protocol validity should be based on an empirical check rather than on theory-based assurances.

Dietary fiber intakes of nursing home residents and independent-living older adults

Daily dietary fiber intakes were determined for two groups of older adults with significantly different bowel habits: nursing-home (NH) residents who habitually took laxatives and independent-living (IL) adults who took laxatives occasionally. Fiber intakes were calculated from neutral detergent fiber (NDF) and Southgate total dietary fiber values. IL subjects (n = 7) consumed on average 9.0 +/- 1.6 g NDF and 18.8 +/- 4.6 g total fiber daily. The NH menu provided a similar amount of NDF but more total fiber. NH residents (n = 6) consumed approximately 70-85% of the fiber served. When fiber intakes were expressed as energy, NH and IL subjects consumed similar amounts of NDF but IL subjects consumed less total fiber. Grain products were major fiber sources for both groups; IL subjects consumed more fiber from fruits. Comparisons of fiber intakes, bowel function, lifestyles, and medications suggest that dietary fiber is only part of the basis for inadequate large bowel function experienced by some elderly populations.

Effect of wheat bran on bowel function and fecal calcium in older adults

Seven healthy older volunteers participated in a 33-day study consisting of three sample collection periods, a 10-day control, and two 10-day experimental periods. Subjects consumed their usual self-selected diets throughout and a daily wheat bran supplement (30 g) during the two experimental periods. Food intake was recorded daily by subjects and accuracy and completeness checked daily by personal interview. Apparent calcium absorption decreased significantly from 22.1 +/- 5.6% (mean +/- SD) during the control to 8.6 +/- 5.2% during the second bran period. The wheat bran supplement significantly increased wet and dry stool weights but had no effect on stool moisture or defecation frequency. Gastrointestinal transit time of a dose of chromium decreased significantly, from 75 +/- 33 to 54 +/- 19 hr; of a dose of polyethylene glycol insignificantly, from 98 +/- 59 to 69 +/- 46 hr. Mean recovery of 21 doses of chromium of 98.7 +/- 5.0% verified that stool collection was complete. The results suggest that the ability of wheat bran to regulate bowel function in the apparently healthy older adult may be accompanied by increased fecal calcium losses similar to what has been reported for younger adults.

Dynamic modifications of the popliteal arterial axis in the sagittal plane during flexion of the knee

The authors have studied, on the basis of purely radiologic data, the modifications of the popliteal arterial axis during flexion of the knee. They note the appearance in the sagittal plane of very marked flexures of the upper part of the artery, while the lower part describes a harmonious curve. These modifications take place between two fixed points: a cranial fixed point, represented by the origin of the descending artery of the knee, and a caudal fixed point represented by the origin of the anterior tibial artery. The pathologic importance of these modifications of the course of the artery should not be underestimated when obtaining revascularization by means of an arterial prosthesis.

Diagnostic differentiation between reactive and malignant lymphoid cells in serous effusions

Lymphoid cell components in a total of 34 pleural and ascitic aspirates were investigated immunologically. The results indicate that reactive lymphocytes predominate in effusions from non-haemopoietic malignancies and benign conditions, while a significant proportion of fluids from patients with non-Hodgkins lymphoma show unequivocal evidence of lymphomatous involvement. Immunological typing of lymphocytes in serous effusions is a valuable adjunct to conventional methods of diagnosis particularly in those patients in whom invasive procedures are undesirable.

A simple method to estimate neutral detergent fiber content of typical daily menus

The purpose of this research was to develop a simple method to estimate daily intakes of the insoluble fraction of dietary fiber, that portion most effective in increasing stool weight and defecation frequency and decreasing gastrointestinal transit time. Neutral detergent fiber (NDF) contents of 53 foods were determined by analysis and used to calculate the NDF content of typical institutional menus; mean NDF content (n = 14 days) was 10.8 +/- 1.4 g/day. Average NDF content of one serving of fruits and vegetables was approximately 1 g, of the refined grain products, approximately 0.5 g. Estimating daily NDF content of the menus was simplified without a loss of accuracy by substituting the mean NDF content of one serving of refined grains, vegetables, and fruits for the actual values, and by eliminating foods present at less than 1/4 of a serving. Crude fiber was a poor predictor of the NDF in a menu.

Determining compliance with a dietary fiber supplement

The purpose of this pilot study was to evaluate possible ways to determine compliance with a dietary fiber supplement. A wheat bran supplement (30 g daily) significantly increased mean daily wet and dry stool weights (SW) in 7 adults, when compared to SW during an ad libitum low-fiber diet (paired t-test, P less than .01). Because unpaired data would be used during a clinical trial, distribution of the 7 ad libitum low-fiber mean SW observations was used to establish a reference distribution and an upper confidence limit against which the bran supplement SW could be compared. Only one of the seven bran supplement mean SW was above the confidence limit of the low-fiber period, independent of the number of days of collection (2-10) used to calculate the individual mean daily SW. Total fecal output over varying periods of time (2-10 days) suffered the same intersubject and intrasubject variability. Most (5-6) of the bran mean daily SW were above the group mean SW of the low-fiber period. However, this dose of bran was large enough to significantly decrease calcium absorption, and differences in SW produced by lower doses of wheat bran would probably not be as great. The bulk (greater than or equal to 80%) of a single dose of a fecal marker, chromium sesquioxide, which could be incorporated into a specific day's fiber supplement, was recovered in 5 days of excretion during the control period and in 4 days during the bran period. However, the blue color of the chromium before ingestion is clearly a negative feature. Another marker, polyethylene glycol, could not be recovered in excreta when transient time was 4 days or more. In a separate study, demonstration of very little overlap in the concentration of fecal neutral detergent fiber between the control and bran periods suggests that fecal fiber may be a marker of compliance with a fiber supplement.