The effects of a split sleep–wake schedule on neurobehavioural performance and predictions of performance under conditions of forced desynchrony

Extended wakefulness, sleep loss, and circadian misalignment are factors associated with an increased accident risk in shiftwork. Splitting shifts into multiple shorter periods per day may mitigate these risks by alleviating prior wake. However, the effect of splitting the sleep–wake schedule on the homeostatic and circadian contributions to neurobehavioural performance and subjective assessments of one’s ability to perform are not known. Twenty-nine male participants lived in a time isolation laboratory for 13?d, assigned to one of two 28-h forced desynchrony (FD) schedules. Depending on the assigned schedule, participants were provided the same total time in bed (TIB) each FD cycle, either consolidated into a single period (9.33?h TIB) or split into two equal halves (2?×?4.67?h TIB). Neurobehavioural performance was regularly assessed with a psychomotor vigilance task (PVT) and subjectively-assessed ability was measured with a prediction of performance on a visual analogue scale. Polysomnography was used to assess sleep, and core body temperature was recorded to assess circadian phase. On average, participants obtained the same amount of sleep in both schedules, but those in the split schedule obtained more slow wave sleep (SWS) on FD days. Mixed-effects ANOVAs indicated no overall difference between the standard and split schedules in neurobehavioural performance or predictions of performance. Main effects of circadian phase and prior wake were present for both schedules, such that performance and subjective ratings of ability were best around the circadian acrophase, worst around the nadir, and declined with increasing prior wake. There was a schedule by circadian phase interaction for all neurobehavioural performance metrics such that performance was better in the split schedule than the standard schedule around the nadir. There was no such interaction for predictions of performance. Performance during the standard schedule was significantly better than the split schedule at 2?h of prior wake, but declined at a steeper rate such that the schedules converged by 4.5–7?h of prior wake. Overall, the results indicate that when the total opportunity for sleep per day is satisfactory, a split sleep–wake schedule is not detrimental to sleep or performance. Indeed, though not reflected in subjective assessments of performance capacity, splitting the schedule may be of some benefit, given its reduction of neurobehavioural impairment at night and its association with increased SWS. Therefore, for some industries that require operations to be sustained around the clock, implementing a split work–rest schedule may be of assistance.     

Consumption of non–cow’s milk beverages and serum vitamin D levels in early childhood

Background:

Vitamin D fortification of non–cow’s milk beverages is voluntary in North America. The effect of consuming non–cow’s milk beverages on serum 25-hydroxyvitamin D levels in children is unclear. We studied the association between non–cow’s milk consumption and 25-hydroxyvitamin D levels in healthy preschool-aged children. We also explored whether cow’s milk consumption modified this association and analyzed the association between daily non–cow’s milk and cow’s milk consumption.

Methods:

In this cross-sectional study, we recruited children 1–6 years of age attending routinely scheduled well-child visits. Survey responses, and anthropometric and laboratory measurements were collected. The association between non–cow’s milk consumption and 25-hydroxyvitamin D levels was tested using multiple linear regression and logistic regression. Cow’s milk consumption was explored as an effect modifier using an interaction term. The association between daily intake of non–cow’s milk and cow’s milk was explored using multiple linear regression.

Results:

A total of 2831 children were included. The interaction between non–cow’s milk and cow’s milk consumption was statistically significant (p = 0.03). Drinking non–cow’s milk beverages was associated with a 4.2-nmol/L decrease in 25-hydroxyvitamin D level per 250-mL cup consumed among children who also drank cow’s milk (p = 0.008). Children who drank only non–cow’s milk were at higher risk of having a 25-hydroxyvitamin D level below 50 nmol/L than children who drank only cow’s milk (odds ratio 2.7, 95% confidence interval 1.6 to 4.7).

Interpretation:

Consumption of non–cow’s milk beverages was associated with decreased serum 25-hydroxyvitamin D levels in early childhood. This association was modified by cow’s milk consumption, which suggests a trade-off between consumption of cow’s milk fortified with higher levels of vitamin D and non–cow’s milk with lower vitamin D content.Goat’s milk and plant-based milk alternatives made from soy, rice, almonds, coconut, hemp, flax or oats (herein called “non–cow’s milk”) are increasingly available on supermarket shelves. Many consumers may be switching from cow’s milk to these beverages.^1–3 Parents may choose non–cow’s milk beverages for their children because of perceived health benefits. However, it is unclear whether they offer health advantages over cow’s milk or, alternatively, whether they increase the risk of nutritional inadequacy.In the United States and Canada, cow’s milk products are required to contain about 40 IU of vitamin D per 100 mL, making it the major dietary source of vitamin D for children.^4–8 The only other food source with mandatory vitamin D fortification in Canada is margarine, which is required to contain 53 IU per 10 mL (10 g).⁵ Fortification of non–cow’s milk beverages with vitamin D is also possible, but it is voluntary in both countries. Furthermore, there is little regulation on the vitamin D content even if such beverages are fortified.^5,6,9We conducted a study to test the association between total daily consumption of non–cow’s milk and serum 25-hydroxyvitamin D levels in a population of healthy urban preschool-aged children attending routinely scheduled well-child visits. We hypothesized that vitamin D stores would be lower in children who consume non–cow’s milk. The secondary objectives were to explore how consumption of cow’s milk might modify this association and to study the association between daily intake of non–cow’s milk and cow’s milk.     

Effects of the acid–base treatment of corn on rumen fermentation and microbiota,inflammatory response and growth performance in beef cattle fed high-concentrate diet

Beef cattle are often fed high-concentrate diet (HCD) to achieve high growth rate. However, HCD feeding is strongly associated with metabolic disorders. Mild acid treatment of grains in HCD with 1% hydrochloric acid (HA) followed by neutralization with sodium bicarbonate (SB) might modify rumen fermentation patterns and microbiota, thereby decreasing the negative effects of HCD. This study was thus aimed to investigate the effects of treatment of corn with 1% HA and subsequent neutralization with SB on rumen fermentation and microbiota, inflammatory response and growth performance in beef cattle fed HCD. Eighteen beef cattle were randomly allocated to three groups and each group was fed different diets: low-concentrate diet (LCD) (concentrate : forage = 40 : 60), HCD (concentrate : forage = 60 : 40) or HCD based on treated corn (HCDT) with the same concentrate to forage ratio as the HCD. The corn in the HCDT was steeped in 1% HA (wt/wt) for 48 h and neutralized with SB after HA treatment. The animal trial lasted for 42 days with an adaptation period of 7 days. At the end of the trial, rumen fluid samples were collected for measuring ruminal pH values, short-chain fatty acids, endotoxin (or lipopolysaccharide, LPS) and bacterial microbiota. Plasma samples were collected at the end of the trial to determine the concentrations of plasma LPS, proinflammatory cytokines and acute phase proteins (APPs). The results showed that compared with the LCD, feeding the HCD had better growth performance due to a shift in the ruminal fermentation pattern from acetate towards propionate, butyrate and valerate. However, the HCD decreased ruminal pH and increased ruminal LPS release and the concentrations of plasma proinflammatory cytokines and APPs. Furthermore, feeding the HCD reduced bacterial richness and diversity in the rumen. Treatment of corn increased resistant starch (RS) content. Compared with the HCD, feeding the HCDT reduced ruminal LPS and improved ruminal bacterial microbiota, resulting in decreased inflammation and improved growth performance. In conclusion, although the HCD had better growth performance than the LCD, feeding the HCD promoted the pH reduction and the LPS release in the rumen, disturbed the ruminal bacterial stability and increased inflammatory response. Treatment of corn with HA in combination with subsequent SB neutralization increased the RS content and helped counter the negative effects of feeding HCD to beef steers.     

Effects of immunocastration and β-adrenergic agonists on the performance and carcass traits of feedlot finished Nellore cattle

β-Adrenergic agonists (β-AA) are non-hormonal growth promoters which promote muscle hypertrophy in supplemented animals. The effects of two β-AA in combination with the immunocastration technique on the performance and carcass traits were evaluated using 96 feedlot Nellore males in a randomized complete block design with two sex conditions (immunocastrated (IC) v. non-castrated (NC)) and three treatments: CON (no β-agonists added), RH (300 mg of ractopamine hydrochloride/day, for 33 days) or ZH (80 mg of zilpaterol·hydrochloride animal/day for 30 days, removed 3 days for required withdrawal period). The trial was carried for 100 days where in the first 70 days animals did not receive β-AA (phase 1) and during the last 30 days they were treated with β-AA (phase 2). The performance and ultrasound measurements of longissimus muscle area (LMA), backfat thickness (BFT) and rump fat thickness (RFT) were evaluated in both phases. No sex condition v. treatment interactions were observed for any trait. The NC animals had higher average daily gain (ADG) and final BW than the IC animals, but they did not differ in dry matter intake (DMI) and feed efficiency (gain to feed). The NC animals showed greater LMA (P=0.0001) and hot carcass weight (P=0.0006), and smaller BFT (P=0.0007), RFT (P=0.0039) and percentage of kidney, pelvic and heart fat (P<0.0001) when compared with IC animals. The animals fed ZH showed greater ADG (P=0.0002), G : F (P<0.0001) and dressing per cent (P=0.0136) than those fed RH and CON diets. No differences in BW and DMI were observed. A interaction between treatment and time on feed was observed for LMA and BFT, in which the animals fed ZH diet showed greater LMA (P<0.01) and lower BFT (P<0.01) at 100 days than the animals fed RH and CON diets, whereas RH and CON diets did not differ. Immunocastration decreases muscle development and increases carcass finishing. In contrast, β-AA increases muscle and decreases fat deposition. The ZH has a higher action on the muscle metabolism than animals fed RH diet. However, RH diet achieves a better balance because it has an intermediary performance between non-supplemented and ZH animals and does not decrease the carcass fat.     

Plant–soil feedback effects on the performance and functional traits of Dodonaea viscosa in a dry-hot valley,China

Plant–soil feedback has been widely studied and may be particularly important in resource-poor areas. However, the roles of direct and indirect biotic effect in affecting plant growth and functional traits in this process still remained unclear. The aim of this study was to explore the roles of soil biota in affecting plant performance and traits by conducting a two-phase feedback experiment in a dry-hot valley, with a conditioning phase during which there were Dodonaea viscosa or no D. viscosa growing in the soil and a feedback phase in which the effect of the conditioned soil biota on D. viscosa performance was measured. Soil N was reduced by the presence of D. viscosa during the conditioning phase. However, D. viscosa showed a positive plant–soil feedback. In the feedback phase, the D. viscosa-conditioned soil increased the stem diameter, total biomass, and leaf dry mass content of D. viscosa, while the specific leaf area was significantly lower in D. viscosa-conditioned soil than that in bare soil. In contrast, soil sterilization had a negative effect on the growth of D. viscosa, with a significant reduction in biomass, especially in D. viscosa-conditioned soil, and soil sterilization significantly increased the root:shoot biomass ratio and litter mass. Furthermore, we showed that although the biota-driven changes in enzyme activities correlated with leaf N and especially P amount, the enzyme activity was not the main reason to promote D. viscosa growth in conditioned soil. These results suggest that the positive biotic feedback effect was superior to the negative nutrient-depleted effect on D. viscosa growth, and the direct biotic feedback effect would drive the positive effect of soil biota to a greater extent than the indirect effect. The positive biotic plant–soil feedback in dry-hot valley plays an important role in ecosystem restoration and helps in understanding plant adaptation to the local environment in this area.

     

The effects of salicylate on the activity of rat liver tyrosine–2-oxoglutarate aminotransferase in vitro and in vivo

1. Salicylate, in concentrations of 0.25mm and above, enhances the basal activity of tyrosine–2-oxoglutarate aminotransferase in homogenates of rat liver incubated in the absence of added pyridoxal 5′-phosphate (endogenous activity). The effect is decreased by increasing the concentration of the cofactor. 2. The intraperitoneal administration of sodium salicylate enhances the activity of rat liver tyrosine aminotransferase; the major effect during the first hour being on the enzyme in the absence of added pyridoxal phosphate. Actinomycin D prevents the induction of the enzyme by cortisol and tryptophan. Induction by pyridoxine or salicylate is 50% inhibited by actinomycin D. The effects of the injections of various combinations of cortisol, pyridoxine and salicylate were also studied in the absence or presence of actinomycin D. 3. It is suggested that salicylate induces rat liver tyrosine aminotransferase by displacing its protein-bound cofactor and that a cofactor-type induction of the hepatic enzyme occurs in pyridoxine-treated rats.     

Effect of early postpartum PGF2α treatment on reproductive performance in dairy cows with calving and puerperal traits

The objective of this study was to evaluate the effects of early postpartum PGF two alpha treatment on reproductive performance in dairy cows with calving and puerperal traits. A total of 363 Holstein cows (128 primiparous and 235 multiparous) were selected based on the presence of at least one of calving and puerperal traits (dystocia, retained placenta, twin, abortion, and postpartum uterine infections) and were assigned to two groups (treatment and control) irrespective of presence or absence of luteal tissue. Cows in the treatment group were treated twice with 25 mg dinoprost 8 h apart on day 20 postpartum, and for the control group saline placebo was administered. As it was speculated that the timing of a second dose would mimic the release of endogenous PGF2α from the uterus, our hypothesis was that two doses of PGF2α 8 h apart may increase the duration of elevated plasma prostaglandin F2α metabolite concentration in these cows. Recorded reproductive variables included days to first estrus, days to first AI, first service conception rate, pregnancy by 150 days in milk, service per conception, open days, and the percentage of repeat breeder animals. The data were analyzed using SPSS (Version 15) (IBM North America, New York, NY, USA) and Minitab (Version 14) (Minitab, State College, PA, USA). Although early postpartum PGF2α treatment had no effect on days to first estrus (36.7 days vs. 34.9 days, P = 0.056) and days to first AI (70.5 days vs. 72.2 days, P = 0.537), it increased first service conception rate (47.1% vs. 27.6%, P < 0.001); and this was more remarkable in primiparous cows (64.7% vs. 25%, P < 0.001). PGF2α treatment reduced the mean service per conception (1.92 vs. 2.72, P < 0.001) and the mean open days (112 days vs. 144 days, P < 0.001), and increased pregnancy by 150 days in milk (DIM) (80% vs. 66%, P = 0.004). The prevalence of repeat breeder syndrome in cows with calving and puerperal traits was reduced by PGF2α treatment (10% vs. 29.8%, P < 0.001). In conclusion, treatment of cows with calving and puerperal traits twice with a luteolytic dose of PGF2α 8 h apart on Day 20 postpartum improved reproductive performance and reduced the prevalence of repeat breeder syndrome.     

Effects of long-term treatment with 17 β-estradiol and medroxyprogesterone acetate on water maze performance in middle aged female rats

Although previous research has indicated that hormone replacement therapy benefits memory in menopausal women, several recent studies have shown either detrimental or no effects of treatment. These inconsistencies emphasize the need to evaluate the role of ovarian hormones in protecting against age-related cognitive decline in an animal model. The present study investigated the effects of long-term hormone treatment during aging on the Morris water maze. Female Long Evans hooded rats were ovariectomized at middle age (12-13 months) and were immediately placed in one of five groups: no replacement, chronic 17 β-estradiol only, chronic 17 β-estradiol and progesterone, chronic 17 β-estradiol and medroxyprogesterone acetate (MPA), or cyclic 17 β-estradiol only. 17 β-estradiol was administered in the drinking water in either a chronic or cyclic (3 out of 4 days) fashion. Progesterone and MPA were administered via subcutaneous pellets. Following 6 months of hormone treatment, animals were tested on the Morris water maze. Animals performed four trials a day for 4 days and after the final day of testing a subset of animals completed a probe trial. Across 4 days of testing, rats receiving 17 β-estradiol in combination with MPA performed significantly worse than all other groups receiving hormone replacement. In addition on the last day of testing, chronic 17 β-estradiol administration was more beneficial than cyclic administration and no replacement. Thus compared to other hormone-treated groups, long-term 17 β-estradiol treatment in combination with MPA results in impaired performance on the spatial Morris water maze.     

Investigation of seasonal variations in cow serum retinol and β -carotene by high performance liquid chromatographic method

• 1.1. High performance liquid chromatography (HPLC) was used to determine β-carotene and retinol in cow serum.
• 2.2. Two groups of state and private farm cows (Groups 1 and 2) were used to assess seasonal variation when different food sources were fed to cows on serum β -carotene and retinol concentrations.
• 3.3. Mean serum concentrations of β-carotene and retinol from October to April in both Groups 1 and 2 cows were lower (P < 0.05) than in the other months when the cows were fed various combination of maize silage, alfalfa and carrot residues and grass hay, respectively.
• 4.4. Mean serum β-carotene and retinol concentrations in June and July were higher (P < 0.05) than in other months when the cows were in pasture.
• 5.5. Mean serum β-carotene and retinol concentrations in May, August and September were lower (P < 0.05) than in June and July and higher (P < 0.05) than in other months when a lesser amount of green pasture was available to the cows.
• 6.6. There was a seasonal variation (P < 0.05) in serum β -carotene and retinol concentrations. When the carotene intake is very high, conversion of β -carotene to retinol decreases. Mean monthly serum β -carotene and retinol concentrations showed that combination of alfalfa hay and maize silage, and grass hay and carrot residues can maintain adequate serum β-carotene and retinol concentrations during the dry season.

     

The effects of reindeer grazing on the composition and species richness of vegetation in forest–tundra ecotone

We conducted an 8-year exclosure experiment (1999–2006) in a forest–tundra ecotonal area in northwestern Finnish Lapland to study the effects of reindeer grazing on vegetation in habitats of variable productivity and microhabitat structure. The experimental sites included tundra heath, frost heath and riparian habitats, and the two latter habitats were characterized by hummock-hollow ground forms. The total cover of vegetation, cover of willow (Salix spp.), dwarf birch (Betula nana), dwarf shrubs, forbs and grasses (Poaceae spp.) increased in exclosures in all habitats. The increase in the total cover of vegetation and in the covers of willow and dwarf birch tended to be greatest in the least productive tundra heath. Opposing to the increase in the dominant vascular plant groups, the cover and species number of bryophytes decreased in exclosures. We conclude that the effects of reindeer grazing on vegetation composition depend on environmental heterogeneity and the responses vary among plant groups. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Moose in our neighborhood: Does perceived hunting risk have cascading effects on tree performance in vicinity of roads and houses?

Like large carnivores, hunters both kill and scare ungulates, and thus might indirectly affect plant performance through trophic cascades. In this study, we hypothesized that intensive hunting and enduring fear of humans have caused moose and other forest ungulates to partly avoid areas near human infrastructure (perceived hunting risk), with positive cascading effects on recruitment of trees. Using data from the Norwegian forest inventory, we found decreasing browsing pressure and increasing tree recruitment in areas close to roads and houses, where ungulates are more likely to encounter humans. However, although browsing and recruitment were negatively related, reduced browsing was only responsible for a small proportion of the higher tree recruitment near human infrastructure. We suggest that the apparently weak cascading effect occurs because the recorded browsing pressure only partly reflects the long‐term browsing intensity close to humans. Accordingly, tree recruitment was also related to the density of small trees 5–10 years earlier, which was higher close to human infrastructure. Hence, if small tree density is a product of the browsing pressure in the past, the cascading effect is probably stronger than our estimates suggest. Reduced browsing near roads and houses is most in line with risk avoidance driven by fear of humans (behaviorally mediated), and not because of excessive hunting and local reduction in ungulate density (density mediated).     

The effects of gap disturbance on nitrogen cycling and retention in late-successional northern hardwood–hemlock forests

Late-successional forests in the upper Great Lakes region are susceptible to nitrogen (N) saturation and subsequent nitrate (NO₃⁻) leaching loss. Endemic wind disturbances (i.e., treefall gaps) alter tree uptake and soil N dynamics; and, gaps are particular susceptible to NO₃⁻ leaching loss. Inorganic N was measured throughout two snow-free periods in throughfall, forest floor leachates, and mineral soil leachates in gaps (300–2,000 m², 6–9 years old), gap-edges, and closed forest plots in late-successional northern hardwood, hemlock, and northern hardwood–hemlock stands. Differences in forest water inorganic N among gaps, edges, and closed forest plots were consistent across these cover types: NO₃⁻ inputs in throughfall were significantly greater in undisturbed forest plots compared with gaps and edges; forest floor leachate NO₃⁻ was significantly greater in gaps compared to edges and closed forest plots; and soil leachate NO₃⁻ was significantly greater in gaps compared to the closed forest. Significant differences in forest water ammonium and pH were not detected. Compared to suspected N-saturated forests with high soil NO₃⁻ leaching, undisturbed forest plots in these late-successional forests are not losing NO₃⁻ (net annual gain of 2.8 kg ha⁻¹) and are likely not N-saturated. Net annual NO₃⁻ losses were observed in gaps (1.3 kg ha⁻¹) and gap-edges (0.2 kg ha⁻¹), but we suspect these N leaching losses are a result of decreased plant uptake and increased soil N mineralization associated with disturbance, and not N-saturation.     

Central effects of TNFα on thermogenesis and fever in the rat

Intracerebroventricular (icv) injection of purified recombinant human tumour necrosis factor (TNF , 4–8g) in conscious rats, produced increases in colonic temperature (1.0°C) and resting oxygen consumption (VO₂, 14%) which were maximal after 80–90 minutes. Pretreatment with propranolol (10mg/kg s.c) significantly inhibited the rise in VO₂, and prevented the increase in body temperature. Icv injection of an antagonist to corticotropin releasing factor (-helical CRF 9-41, 25 g), which prevents the pyrogenic and thermogenic actions of interleukin-1, did not influence the effects of TNF on temperature or VO₂. Injection of a fragment of TNF (113–130 amino acid sequence) did not affect body temperature or VO₂. TNF injection (icv) significantly increased brown adipose tissue (BAT)in vitro mitochondrial GDP binding, and this effect was slightly inhibited, but not prevented, by surgical denervation of the tissue, and was unaffected by pretreatment with -helical CRF 9-41. These data indicate that TNF can stimulate thermogenesis by a direct central action. The effects are largely, but not totally, dependent on the sympathetic nervous system but, unlike the thermogenic actions of interleukin they do not require release of CRF.     

Diverse effects of residues 74–78 in ribosomal protein S12 on decoding and antibiotic sensitivity

Ribosomal protein S12 plays key roles in the ribosome’s response to the error-promoting antibiotic streptomycin and in modulating the accuracy of translation. The discovery that substitutions at His76 in S12, distant from the streptomycin binding site, conferred streptomycin resistance in the thermophilic bacterium Thermus thermophilus prompted us to make similar alterations in the S12 protein of Escherichia coli. While, none of the E. coli S12 mutations confers streptomycin resistance, they all have distinct effects on the accuracy of translation. In addition, a subset of the S12 alterations renders the cells hypersensitive to fusidic acid, an inhibitor of the translocation step of translation. These results indicate that the His 76 region of ribosomal protein S12 plays key roles in tRNA selection and translocation steps of protein synthesis, consistent with its interaction with elongation factors EF-Tu and EF-G, as deduced from structural studies of ribosomal complexes.     

Intensity-dependent effects of cattle and sheep grazing in sand grasslands — Does livestock type really matter?

Aims

By analysing cattle- and sheep-grazed sand grasslands, we tested the following hypotheses: (i) livestock type has a stronger effect on the vegetation characteristics than grazing intensity; (ii) sheep grazing results in lower biomass and species and functional diversity than cattle grazing, regardless of intensity; and (iii) increased grazing intensity causes a shift of the trait composition in grasslands.

Location

Sand grasslands in the Nyírség region, East Hungary.

Methods

We selected 26 sand grassland sites grazed by cattle or sheep and classified them into four intensity levels. Vegetation composition was surveyed in 2 m × 2 m plots. We harvested the above-ground biomass from 20 cm × 20 cm plots; then dried and sorted it to live biomass, litter, moss, and lichen. We compared Rao dissimilarity index, species richness, Shannon diversity, evenness, and the community-weighted means of nine vegetative and generative traits along a grazing intensity gradient. We calculated functional richness, evenness, and divergence for comparison.

Results

We found that some diversity metrics and community-weighted means of most studied traits were significantly affected by grazing intensity. Several characteristics were also affected by the interaction of grazing intensity and livestock type, but none of the studied characteristics was affected by livestock type in itself. Increasing Rao dissimilarity index peaking at the fourth grazing intensity level was detected, but for other multitrait indices, no such changes were proven, except for functional divergence, which was the lowest at the first intensity level. Graminoid, forb, and litter biomass were significantly affected by intensity, but none of the biomass fractions was affected by livestock type.

Conclusions

We suggest that for the management of sand grasslands, grazing intensity should be carefully adjusted, considering not only livestock units per hectare. For practical recommendations, well-defined, long-term experiments studying different livestock and habitat types along an intensity gradient would be essential.     

Mutagenic activation and carcinogenicity of aminoazo dyes ortho-aminoazotoluene and 3′-methyl-4-dimethylaminoazobenzene in experiments on suckling mice

It is found that after administration of 3′-methyl-4-dimethylaminoazobenzene (3′-Me-DAB,) which was hepatocarcinogenic to rats, in suckling mice, the number of neoplastic lesions in the liver of mice was 3 times higher than after analogous administration of equimolar dose of ortho-aminoazotoluene (OAT)). However, in the Ames test (TA-98 strain of Salmonella typhimurium) with activation by hepatic enzymes (S-9 fraction) of both intact and Aroclor-1254-induced mice and rats OAT contributed by an order of magnitude to revertant colonies compared to 3′-Me-DAB. In vivo inhibition of sulfotransferase activity, the enzyme which catalyzes the final stage of the mutagenic activation of aminoazo dyes, had no effect on carcinogenicity of 3′-Me-DAB but more than 4 times elevated that of OAT. It was concluded that the mechanism of carcinogenic action of aminoazo dyes studied is not genotoxic and that the carcinogenic potential of OAT is lost in the process of mutagenic activation.     

In vivo effects of zoledronic acid on peripheral γδ T lymphocytes in early breast cancer patients

Introduction

Amino-bisphosphonates are potent activators of human γδ T cells. The aim of our study was to evaluate the immunomodulating properties of a single-dose of zoledronic acid (ZA) on γδ T cells in a select group of disease-free breast cancer patients with osteopenia.

Materials and methods

Blood samples were obtained, from 23 patients, before and 7, 28, 56, 90 and 180 days after a single-dose (4 mg) of ZA and analyzed by flow cyometry.

Results

A significant decrease of the different γδ T cell subsets was observed: Naïve (CD3+/Vdelta2+/CD45RA+/CD27+) after 180 days (P < 0.01); Central Memory (CD3+/Vdelta2+/CD45RA-CD27+) after 28 (P < 0.05), 90 (P < 0.01) and 180 days (P < 0.01); and Effector Memory (CD3+/Vdelta2+/CD45RA-/CD27-) after 56 (P < 0.01) and 90 (P < 0.05) days. Based on the observed γδ T cells kinetics patients could be divided in two groups: “responders” that showed a significant decrease in total numbers of γδ T cells and “non-responders” that showed no significant change. However, in vitro phosphoantigen stimulation of patients cells did not show significant differences in terms of IFN-γ response by Vδ2 T cells.

Conclusion

We describe for the first time a long-lasting activation of effector subsets of γδ T cells in disease-free breast cancer patients after a single-dose of ZA. Our results highlight the need to further investigate the clinical significance of the immunomodulating properties of N-BPs.