Biomedical subjects

D N Cox

Publications and source records attributed to D N Cox.

At least 19 recordsLinked to original sources

PubMed2004

Predicting intentions to consume functional foods and supplements to offset memory loss using an adaptation of protection motivation theory.

The widespread use of dietary supplements and so-called 'functional foods' is thought to be partially motivated by self-control of health. However, whilst consumers want foods associated with well-being or disease prevention, they are unlikely to be willing to compromise on taste or technology. This presents a dilemma for promoters of functional foods. Middle-aged consumers' intentions to consume functional foods or supplements that may improve memory were tested within an adaptation of Protection Motivation theory (PMT). Participants evaluated text descriptions of four products described as: having an unpleasant bitter taste (Natural-FF); having 'additives' to reduce bitterness (Sweetened-FF); being genetically modified to enhance function (GM-FF) and Supplements. Participants were recruited as being of high and low perceived vulnerability to memory failure. In total, 290 middle-aged consumers (aged 40-60 years) participated in the study. Motivations to consume the GM-FF were the lowest. There were gender differences between intention to consume the supplements, Natural-FF and Sweetened-FF and product differences within genders. Women were less favourable than men in their attitudes towards genetic modification in general. Regression analyses indicated that PM predictors of intention to consume functional foods or supplements explained 59-63% of the variance (R2). Overall, perceived 'efficacy' (of the behaviour) and self-efficacy were the most important predictors of intentions to consume.

Adult↗

PubMed2001

Bazooka and atypical protein kinase C are required to regulate oocyte differentiation in the Drosophila ovary.

The par genes, identified by their role in the establishment of anterior-posterior polarity in the Caenorhabditis elegans zygote, subsequently have been shown to regulate cellular polarity in diverse cell types by means of an evolutionarily conserved protein complex including PAR-3, PAR-6, and atypical protein kinase C (aPKC). The Drosophila homologs of par-1, par-3 (bazooka, baz), par-6 (DmPar-6), and pkc-3 (Drosophila aPKC, DaPKC) each are known to play conserved roles in the generation of cell polarity in the germ line as well as in epithelial and neural precursor cells within the embryo. In light of this functional conservation, we examined the potential role of baz and DaPKC in the regulation of oocyte polarity. Our analyses reveal germ-line autonomous roles for baz and DaPKC in the establishment of initial anterior-posterior polarity within germ-line cysts and maintenance of oocyte cell fate. Germ-line clonal analyses indicate both proteins are essential for two key aspects of oocyte determination: the posterior translocation of oocyte specification factors and the posterior establishment of the microtubule organizing center within the presumptive oocyte. We demonstrate BAZ and DaPKC colocalize to belt-like structures between germarial cyst cells. However, in contrast to their regulatory relationship in the Drosophila and C. elegans embryos, these proteins are not mutually dependent for their germ-line localization, nor is either protein specifically required for PAR-1 localization to the fusome. Therefore, whereas BAZ, DaPKC, and PAR-1 are functionally conserved in establishing oocyte polarity, the regulatory relationships among these genes are not well conserved, indicating these molecules function differently in different cellular contexts.

Animals↗

PubMed2001

Drosophila par-1 is required for oocyte differentiation and microtubule organization.

BACKGROUND: Drosophila oocyte determination involves a complex process by which a single cell within an interconnected cyst of 16 germline cells differentiates into an oocyte. This process requires the asymmetric accumulation of both specific messenger RNAs and proteins within the future oocyte as well as the proper organization of the microtubule cytoskeleton, which together with the fusome provides polarity within the developing germline cyst. RESULTS: In addition to its previously described late oogenic role in the establishment of anterior-posterior polarity and subsequent embryonic axis formation, the Drosophila par-1 gene is required very early in the germline for establishing cyst polarity and for oocyte specification. Germline clonal analyses, for which we used a protein null mutation, reveal that Drosophila par-1 (par-1) is required for the asymmetric accumulation of oocyte-specific factors as well as the proper organization of the microtubule cytoskeleton. Similarly, somatic clonal analyses indicate that par-1 is required for microtubule stabilization in follicle cells. The PAR-1 protein is localized to the fusome and ring canals within the developing germline cyst in direct contact with microtubules. Likewise, in the follicular epithelium, PAR-1 colocalizes with microtubules along the basolateral membrane. However, in either case PAR-1 localization is independent of microtubules. CONCLUSIONS: The Drosophila par-1 gene plays at least two essential roles during oogenesis; it is required early in the germline for organization of the microtubule cytoskeleton and subsequent oocyte determination, and it has a second, previously described role late in oogenesis in axis formation. In both cases, par-1 appears to exert its effects through the regulation of microtubule dynamics and/or stability, and this finding is consistent with the defined role of the mammalian PAR-1 homologs.

Animals↗

PubMed2001

Yb modulates the divisions of both germline and somatic stem cells through piwi- and hh-mediated mechanisms in the Drosophila ovary.

The coordinated division of distinctive types of stem cells within an organ is crucial for organogenesis and homeostasis. Here we show genetic interactions among fs(1)Yb (Yb), piwi, and hedgehog (hh) that regulate the division of both germline stem cells (GSCs) and somatic stem cells (SSCs), the two constituent stem cell populations of the Drosophila ovary. Yb is required for both GSC and SSC divisions; loss of Yb function eliminates GSCs and reduces SSC division, while Yb overexpression increases GSC number and causes SSC overproliferation. We also show that Yb acts via the piwi- and hh-mediated signaling pathways that emanate from the same signaling cells to control GSC and SSC division, respectively. hh signaling also has a minor effect in GSC division.

Animals↗

PubMed2000

Determination of energy density of freely selected diets: methodological issues and implications.

BACKGROUND: There is increasing evidence that dietary energy density (ED, kJ/g) may be an important dietary characteristic, particularly in respect to control of energy intake; however, there are no agreed methods for deriving the ED of freely selected diets, and ED values may be markedly affected by the inclusion or exclusion of specific dietary items, particularly beverages. OBJECTIVE: To highlight the consequences of using six different methods of ED calculation, and their implications for characterizing differences between weight status groups and identifying associations of ED with macronutrient intakes. DESIGN: ED was calculated using six defined methods: (1) all food and beverages; (2) all food and energy beverages; (3) food, milk and alcohol; (4) food only; (5) all dry matter; (6) protein, carbohydrate and fat only, of varying exclusions of different beverages and water. For illustrative purposes, data from 41 lean (LE, body mass index (BMI) 20-25 kg/m2) and 34 obese (OB, BMI>/=30 kg/m2) adults who kept 4-day weighed dietary intake records are described. RESULTS: ED values (and coefficient of variation, CV) differed substantially by methods of calculation. OB reported significantly greater mean ED compared with LE by one method (all food, milk and alcohol, excluding other non-alcoholic beverages); however, the opposite was found using another method (dry weight). For most calculation methods, ED was negatively associated with percentage energy from carbohydrate for LE, in contrast to OB. All methods found positive correlations for ED and fat (g) among LE, but only one method found such a correlation among OB. Similarly, three methods produced positive correlations between ED and percentage energy fat amongst LE; however, this was only observed amongst OB with one method. CONCLUSIONS: Methods of calculating ED of freely selected diets must be carefully defined, and can markedly influence apparent relationships of ED with other dietary measures and subject characteristics. International Journal of Obesity (2000)24, 49-54

Adult↗

PubMed2000

piwi encodes a nucleoplasmic factor whose activity modulates the number and division rate of germline stem cells.

piwi represents the first class of genes known to be required for stem cell self-renewal in diverse organisms. In the Drosophila ovary, piwi is required in somatic signaling cells to maintain germline stem cells. Here we show that piwi encodes a novel nucleoplasmic protein present in both somatic and germline cells, with the highly conserved C-terminal region essential for its function. Removing PIWI protein from single germline stem cells significantly decreases the rate of their division. This suggests that PIWI has a second role as a cell-autonomous promoter of germline stem cell division. Consistent with its dual function, over-expression of piwi in somatic cells causes an increase both in the number of germline stem cells and the rate of their division. Thus, PIWI is a key regulator of stem cell division - its somatic expression modulates the number of germline stem cells and the rate of their division, while its germline expression also contributes to promoting stem cell division in a cell-autonomous manner.

Animals↗

PubMed1999

Sensory and hedonic associations with macronutrient and energy intakes of lean and obese consumers.

OBJECTIVE: To establish differences between lean and obese subjects in subjective reports of predominant taste and texture attributes of 'foods as eaten', and the relationships of these qualities to hedonic preference and objective measures of dietary intake and composition. DESIGN: Free-living subjects received instruction in a laboratory and kept diaries of foods eaten at home. SUBJECTS: 41 lean (body mass index (BMI) 20-25 kg/m2) and 35 obese (BMI > or = 30 kg/m2), non-dieting healthy adults. MEASUREMENTS: Subjects kept four-day weighed dietary intake records, simultaneously assigning ratings for perceived pleasantness and predominant sensory attributes (taste and texture) of food eaten, and completed the Dutch Eating Behaviour questionnaire (DEBQ). Anthropometric measures included body composition assessed by bioelectrical impedance. RESULTS: By all anthropometric measures (except height) the obese group was significantly larger than the lean group, but no significant differences were found for DEBQ scores. There were no significant group differences between pleasantness scores overall, nor for foods classified by predominant taste. Whilst macronutrient intakes did not differ, the obese group's mean dietary energy density was significantly higher, and they reported significantly greater dietary energy from 'salty' foods. For the obese group, the percentage of 'salty' foods eaten correlated strongly with energy density. A strong positive association was found between 'liking extremely' and 'sweet' foods for the lean group, but no clear associations were found for any particular taste and hedonic rating for the obese group. Whilst both groups used similar texture descriptors, there were not clear or unambiguous differences in their assignment or association with other measures. CONCLUSIONS: The results suggest that obese and lean subjects do not self-select diets with markedly different perceived sensory or hedonic attributes. However obese subjects appear to consume a diet higher in energy density, which is particularly associated with intakes of salty/savoury (rather than sweet) food items.

Adolescent↗

PubMed1998

A novel class of evolutionarily conserved genes defined by piwi are essential for stem cell self-renewal.

Germ-line stem cells (GSCs) serve as the source for gametogenesis in diverse organisms. We cloned and characterized the Drosophila piwi gene and showed that it is required for the asymmetric division of GSCs to produce and maintain a daughter GSC but is not essential for the further differentiation of the committed daughter cell. Genetic mosaic and RNA in situ analyses suggest that piwi expression in adjacent somatic cells regulates GSC division. piwi encodes a highly basic novel protein, well conserved during evolution. We isolated piwi homologs in Caenorhabditis elegans and humans and also identified Arabidopsis piwi-like genes known to be required for meristem cell maintenance. Decreasing C. elegans piwi expression reduces the proliferation of GSC-equivalent cells. Thus, piwi represents a novel class of genes required for GSC division in diverse organisms.

Amino Acid Sequence↗

PubMed1998

Sensory and hedonic judgments of common foods by lean consumers and consumers with obesity.

OBJECTIVE: To establish differences between lean subjects and subjects with obesity in subjective reports of predominant taste and texture attributes of common foods, and the relationships of these qualities and foods with overall liking. RESEARCH METHODS AND PROCEDURES: Twenty lean (body mass index: 20 to 25 kg/m2) nondieting healthy adults and 23 (body mass index: > or = 30 kg/m2) nondieting healthy adults with obesity assigned ratings for pleasantness and predominant sensory attributes to 50 common foods in 14 food groups using a questionnaire. They completed the Dutch Eating Behavior Questionnaire. Body composition was assessed by bioelectrical impedance. RESULTS: There were no significant group differences between pleasantness scores overall; however, lean subjects assigned higher scores to fruits and vegetables, to foods self-classified as sweet and as salty/savory, and to foods grouped in the highest and lowest quintiles of percentage food energy from fat. There were no group differences in free-choice texture descriptors applied to foods, but correspondence analysis revealed that subjects with obesity associated coarse, slippery, tough, and fatty textures with "dislike extremely," whereas lean subjects associated grainy, moist, doughy, and fibrous texture with "like extremely." Analyses reduced texture terms to 39 key descriptors for use in subsequent work. Groups did not significantly differ in reported external or restrained eating behaviors, but subjects with obesity scored significantly higher for reported emotional eating. DISCUSSION: Differences in preferences for listed common foods exist between weight status groups according to taste, food group, and texture. Consumers can make textural descriptions of foods that could be used to assess sensory and hedonic qualities of actual food choices.

Adolescent↗

PubMed1998

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on consumer choice and nutrient intakes.

This study reports results from a randomized controlled intervention trial, focusing on: (1) the identification of successful consumer strategies for increasing fruit and vegetable intakes to the recommended levels of more than five (80 g) portions per day and (2) impact on overall diet and nutrient intakes. Adult men and women (n 170) fulfilling the main recruitment criterion of eating less than five fruit and vegetable portions per day but contemplating increasing intakes were recruited. Complete valid dietary data was provided by 101 intervention (fifty-nine estimated fruit and vegetable intakes, and forty-two simultaneous weighted total dietary and estimated fruit and vegetable intakes) and twenty-four control subjects (weighed total dietary intakes). Intervention advice included the specific association of high fruit and vegetable intake with reduced risk of disease, practicalities, and portion definition with a target intake of greater than five 80 g fruit and vegetable portions per day for 8 weeks. There were significant effects (P < 0.001) on weighed intakes of fruit and vegetables in the intervention group, rising from 324 (SE 25) to 557 (SE 31) g/d and reflected by validated portion measures at 8 weeks intervention. Successful strategies chosen by 'achievers' of the target intake (65% of subjects) were conventional (fruit as a snack, vegetables with main meals etc.) and favoured fruit. There were significant increases in percentage energy from carbohydrate (from sugars not starch), vitamin C, carotenes and NSP and there was a significant decrease in percentage energy from fat for subjects who had high fat intakes (> 35% energy) at baseline. Follow-up self-reported measures at 6 and 12 months indicated mean intakes of 4.5 and 4.6 defined portions/d respectively, suggesting some sustainable effect. In conclusion, the intervention led to significant increases in fruit and vegetable intakes largely via conventional eating habits, with some desirable effects on macro- and micronutrient intakes.

Adolescent↗

PubMed1998

Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on attitudes towards dietary change.

To assess the response of low consumers of fruit and vegetables to a nutrition education intervention programme, data were collected from 104 adults on attitudinal variables related to 'eating more fruit, vegetables and vegetable dishes'. Questionnaires (based on the theory of planned behaviour) assessing perceived barriers to increasing fruit and vegetable consumption were administered before an action-orientated intervention programme and at the end of the intervention period (8 weeks). Questionnaire scores for belief-evaluations in the intervention groups pre- and post-study indicated that support of family and friends, food costs, time constraints and shopping practicalities (in order to increase intake of fruit, vegetable and vegetable dishes) were barriers to greater consumption of these foodstuffs. Perceived situational barriers to increasing intakes of fruits and vegetables were: limited availability of vegetables, salads and fruit at work canteens, take-aways, friends' houses and at work generally. Following the intervention the number of visits to the shops was perceived as a greater barrier for increasing intakes of fruit and vegetables. Perceived practical opportunities for increasing intakes high-lighted drinking fruit juice, taking fruit as a dessert, having fruit as a between-meal snack and eating two portions of vegetables with a meal. About two-thirds of intervention subjects achieved the recommended fruit and vegetable target, but it is concluded that practical issues and situational barriers need to be addressed for the success of future public health campaigns.

Adolescent↗

PubMed1998

UK consumer attitudes, beliefs and barriers to increasing fruit and vegetable consumption.

OBJECTIVES: To assess attitudes, predictors of intention, and identify perceived barriers to increasing fruit and vegetable (F&V) intakes. DESIGN: UK nationwide postal survey utilizing the theory of planned behaviour. SUBJECTS: Stratified (by social class and region) random sample of 2020 UK adults providing a modest response rate of 37% (n = 741). RESULTS: Belief measures (e.g. health, cost, taste, etc.) were strongly associated with overall attitudes which were reported as being largely favourable towards fruit, vegetables and, to a lesser extent, vegetable dishes, and were strongly associated with reported intention to increase consumption. Subjects reported they could increase their consumption, but this was only weakly associated with intention to do so. Approximately 50% of respondents reported an intention to increase intakes. Social pressure was strongly associated with reported intention to increase; however, scores indicated low perceived social pressure to change. Evidence of unrealistic optimism concerning perceived intakes and the perceived high cost of fruit may also act as barriers. CONCLUSIONS: Results from this study suggest a lack of perceived social pressure to increase F&V intakes and suggests that public health efforts require stronger and broader health messages that incorporate consumer awareness of low present consumption.

Adolescent↗

PubMed1997

Measuring fruit and vegetable intake: is five-a-day enough?

OBJECTIVE: Validation of a self-monitoring "portions' measurement of fruit and vegetable (F&V) consumption against a standard of weighed intakes. DESIGN: Component of a randomized controlled trial. SETTING: Subjects attended research centres in Reading and Glasgow for instruction and monitoring but undertook free-living dietary changes at home. SUBJECTS: A study sample of 42 adult men and women fulfilling the main recruitment criterion of eating less than five F&V portions/day but contemplating increasing intakes and providing weighted baseline reported energy intakes exceeding (estimated basal metabolic rate x 1.1). INTERVENTIONS: Subjects attended an intensive group advice session which included the specific relationship of high F&V intake with reduced risk of disease; practicalities; portion definition and measurement recording. The target was to exceed five F&V portions/day for 8 weeks. MAIN OUTCOME MEASURES: Self-recorded simultaneous weighed inventories and F&V portion measures. RESULTS: Data from subjects who were not evident under-recorders showed correlations between portion and weighed intakes of r = 0.73, (P < 0.000), although the portions measure tended to under-estimate intakes. Using 80 g/portion the "5-a-day' concept tends to create false negatives (namely consumption could be greater than 400 g whilst recording fewer than five discrete portions) but rarely false positives (namely recorded consumption of less than 400 g did not give measures of more than five discrete portions). CONCLUSIONS: The data suggest that the five portions F&V/day health message, if used in conjunction with defined discrete portions, would encourage desirable consumption exceeding 400 g.

Adolescent↗

PubMed1994

Selenium kinetics, placental transfer, and neonatal exposure in cynomolgus macaques (Macaca fascicularis).

Forty pregnant cynomolgus macaques were treated daily from gestational day 20 to 50 by nasogastric intubation of 0, 25, 150, or 300 micrograms selenium as L-selenomethionine/kg body weight. In each group, 7-8 pregnancies were terminated by hysterotomy at gestational day 100 +/- 2 and the fetuses were examined, while 2-3 pregnancies in each group were allowed to proceed to term. Selenium and soluble glutathione peroxidase were measured in: maternal, neonatal, and fetal plasma and erythrocytes; fetal kidney, liver, muscle, and placenta; and maternal breast milk. The area under the multidose maternal plasma selenium concentration:time curve, the maximum maternal plasma selenium concentration, and the maternal urinary selenium excretion rates were proportional to the L-selenomethionine dose. Selenium concentrations in all fetal and neonatal, tissues were also proportional to maternal L-selenomethionine dose. Glutathione peroxidase was affected only in maternal erythrocytes, fetal kidney, and neonatal plasma. The selenium concentration in fetal plasma was an average 33% of that in maternal plasma. Although selenium concentrations in macaque milk were doubled by the highest dose, intrauterine selenium accumulation accounted for the majority of the neonatal selenium body burden. Despite the elevated selenium concentrations in fetal tissues, neonatal blood, and milk, no deleterious effects on neonates were observed. These results suggest that primate fetuses are well protected against selenium toxicity arising from high maternal L-selenomethionine intakes.

Animals↗

PubMed1994

NPA binding activity is peripheral to the plasma membrane and is associated with the cytoskeleton.

N-1-Naphthylphthalamic acid (NPA) binding activity is released into the supernatant when plasma membranes are subjected to high-salt treatment, indicating that this activity is peripherally associated with the membrane. Extraction of plasma membrane vesicles with Triton X-100 resulted in retention of NPA binding activity in the detergent-insoluble cytoskeletal pellet. Treatment of this pellet with KI released NPA binding activity, actin, and alpha-tubulin. Dialysis to remove KI led to the repolymerization of cytoskeletal elements and movement of NPA binding activity into an insoluble cytoskeletal pellet. NPA binding activity partitioned into the detergent-insoluble cytoskeletal pellet obtained from both zucchini and maize membranes and was released from these pellets by KI treatment. Treatment of a cytoskeletal pellet with cytochalasin B doubled NPA binding activity in the resulting supernatant. Together, these experiments indicate that NPA binding activity is peripherally associated with the plasma membrane and interacts with the cytoskeleton in vitro.

Actins↗

PubMed1992

Effects of excess selenomethionine on selenium status indicators in pregnant long-tailed macaques (Macaca fascicularis).

Forty pregnant long-tailed macaques were treated daily for 30 d with 0, 25, 150, or 300 micrograms selenium as L-selenomethionine/kg body weight. Erythrocyte and plasma selenium and glutathione peroxidase specific activities, hair and fecal selenium, and urinary selenium excretion were increased by and were linearly related to L-selenomethionine dose. Hair selenium was most sensitive to L-selenomethionine dose, with an 84-fold increase in the 300 micrograms selenium/(kg-d) group relative to controls (r = 0.917). Daily urinary selenium excretion (80-fold, r = 0.958), plasma selenium (22-fold, r = 0.885), erythrocyte selenium (24-fold, r = 0.920), and fecal selenium (18-fold, r = 0.911) also responded strongly to L-selenomethionine. Erythrocyte and plasma glutathione peroxidase specific activities increased 154% and 69% over controls, respectively. Toxicity was associated with erythrocyte selenium > 2.3 micrograms/mL, plasma selenium > 2.8 micrograms/mL, and hair selenium > 27 micrograms/g. Plasma, erythrocyte, and hair selenium concentrations may be useful for monitoring and preventing the toxicity of L-selenomethionine administered to humans in cancer chemoprevention trials.

Analysis of Variance↗

PubMed1992

The effect of partial hepatectomy on the metabolism, distribution, and nephrotoxicity of para-methylthiobenzamide in the rat.

Para-Methylthiobenzamide (PMTB) produces injury to the liver and kidney. Toxicity is mediated via its biotransformation to a reactive S,S-dioxide metabolite. The objective of this study was to examine the role of hepatic metabolism in the production of PMTB-induced renal toxicity. Renal injury was assessed in partially hepatectomized and sham-operated rats and the effect of this procedure on the distribution and metabolism of PMTB was examined. The in vitro oxidation of PMTB and [14C]thiobenzamide by rat kidney microsomes was also examined. Plasma urea levels and renal cortical slice uptake of organic ions were used to monitor renal function. Partial hepatectomy alone did not alter renal function nor raise blood urea nitrogen levels. Nephrotoxicity resulted when a nonnephrotoxic dose of PMTB (1.2 mmol/kg) was given to partially hepatectomized rats. An HPLC method was used for measurement of PMTB and its metabolites para-methylthiobenzamide S-oxide (PMTBSO) and para-methylbenzamide (PMBA) in plasma and kidney. Hepatectomy delayed the removal of this dose of PMTB from plasma and allowed greater concentrations of PMTB and PMTBSO to accumulate in plasma and kidney at 6 and 15 hr. The level of PMBA was similar in both groups at 6 hr, but was increased in plasma and kidney of the hepatectomized group at 15 hr. Kidney microsomes rapidly converted PMTB to PMTBSO and small amounts of PMBA. [14C]TB was oxidized by microsomes to thiobenzamide S-oxide, benzamide, and covalently bound metabolites. The results indicate that partial hepatectomy lowered the threshold for the expression of nephrotoxicity by PMTB. This procedure is associated with an increased renal accumulation of PMTB and PMTBSO, which are both sequentially transformed to the toxic metabolite.

Animals↗

PubMed1992

Absorption, distribution and elimination of selenium as L-selenomethionine in non-human primates.

20 adult female macaques (Macaca fascicularis) were given oral doses of L-selenomethionine (L-SeMet) equivalent to 0, 25, 150, 300 and 600 micrograms selenium (Se)/kg body weight, and plasma, erythrocyte, hair, faecal and urine Se concentrations were determined. The macaques were scheduled for 30 daily oral doses of L-SeMet, but systemic toxicity necessitated dose reduction in several animals; two macaques given 600 micrograms Se/kg body weight/day for 10-15 days died, and the concentration of Se in their tissues was determined and compared with Se concentrations in tissues collected from one untreated animal. Circulating and urinary Se concentrations in control macaques were within the normal human ranges. Plasma, erythrocyte, hair and urinary Se concentrations were generally dependent on the dose of L-SeMet administered. Plasma Se reflected more immediately exposure to L-SeMet, whereas erythrocyte Se concentrations increased and decreased more slowly. In some cases, erythrocyte Se was still increasing or showed a plateau after L-SeMet treatment was discontinued. Plasma Se concentrations of 6.7-7.3 ppm were observed in the two animals that died due to acute toxicity to L-SeMet. Neither plasma nor erythrocyte GPx activity was influenced by a single L-SeMet dose, but an increase in erythrocyte GPx activity occurred with continuous exposure. Total tissue Se increased 13-28-fold in macaques given 600 micrograms Se/kg body weight/day for 10-15 days, with the liver and kidneys containing the the highest Se concentrations.

Absorption↗