Indoleamine 2,3-dioxygenase (IDO) is an immunosuppressive enzyme that contributes to tolerance in a number of biological settings. In cancer, IDO activity may help promote acquired tolerance to tumor antigens. The IDO inhibitor 1-methyltryptophan is being developed for clinical trials. However, 1-methyl-tryptophan exists in two stereoisomers with potentially different biological properties, and it has been unclear which isomer might be preferable for initial development. In this study, we provide evidence that the D and L stereoisomers exhibit important cell type-specific variations in activity. The L isomer was the more potent inhibitor of IDO activity using the purified enzyme and in HeLa cell-based assays. However, the D isomer was significantly more effective in reversing the suppression of T cells created by IDO-expressing dendritic cells, using both human monocyte-derived dendritic cells and murine dendritic cells isolated directly from tumor-draining lymph nodes. In vivo, the D isomer was more efficacious as an anticancer agent in chemo-immunotherapy regimens using cyclophosphamide, paclitaxel, or gemcitabine, when tested in mouse models of transplantable melanoma and transplantable and autochthonous breast cancer. The D isomer of 1-methyl-tryptophan specifically targeted the IDO gene because the antitumor effect of D-1-methyl-tryptophan was completely lost in mice with a disruption of the IDO gene (IDO-knockout mice). Taken together, our findings support the suitability of D-1-methyl-tryptophan for human trials aiming to assess the utility of IDO inhibition to block hostmediated immunosuppression and enhance antitumor immunity in the setting of combined chemo-immunotherapy regimens. [Cancer Res 2007;67(2):792-801]

This follow-up investigation examined the relationship among observed time of television watching, physical activity, and body composition in 5- to 6-year-old children previously studied 2 years ago. Activity level on school and nonschool days was measured with the Children’s Activity Rating Scale. Television watching time was assessed by direct observation, and body composition was measured with the body mass index, skinfold thicknesses, and waist/hip ratio. Television watching behavior, which increased from the earlier study, was not associated with body composition. Physical activity was lower during television watching than nontelevision watching time.

Background and purpose Pre-existing diabetes worsens brain functionality in ischemic stroke. We have previously shown that type-2-diabetic rats exhibit enhanced dysfunctional cerebral neovascularization and when these rats are subjected to cerebral ischemic reperfusion injury develop hemorrhagic transformation (HT) and greater neurological deficits. However, our knowledge of vascular and functional plasticity during the recovery phase of diabetic stroke is limited. This study tested the hypothesis that vascular repair is impaired in the post-stroke period in diabetes, and this is associated with poor sensorimotor and cognitive function. We further hypothesized that glycemic control prevents impaired vascularization and improves functional outcome in diabetes. Methods Vascularization was assessed in the ipsilateral and contralateral hemispheres in control, diabetes and diabetes plus metformin groups 14 days after ischemic reperfusion injury as well as in respective sham controls. 3-dimensional reconstruction of the FITC stained vasculature was achieved by confocal microscopy and stereological parameters including vascular volume and surface area were measured. Astrogliosis was determined by GFAP staining. The relative rates of sensorimotor recovery, cognitive decline and spontaneous activity were assessed. Results Vascular density in the peri-infarct area was significantly reduced in diabetes whereas there was reparative neovascularization in control rats. Astroglial swelling and reactivity was more pronounced in diabetic stroke compared to control stroke. Diabetes blunted sensorimotor recovery and also exacerbated anxiety-like symptoms and cognitive deficits. Glycemic control started after stroke partially prevented these changes. Conclusion Diabetes impairs post-stroke reparative neovascularization and impedes the recovery. Glycemic control after stroke can improve neurovascular repair and improve functional outcome.

Dysregulation of cerebral vascular function and, ultimately, cerebral blood flow (CBF) may contribute to complications such as stroke and cognitive decline in diabetes. We hypothesized that 1) diabetes-mediated neurovascular and myogenic dysfunction impairs CBF and 2) under hypoxic conditions, cerebral vessels from diabetic rats lose myogenic properties because of peroxynitrite (ONOO Ϫ )-mediated nitration of vascular smooth muscle (VSM) actin. Functional hyperemia, the ability of blood vessels to dilate upon neuronal stimulation, and myogenic tone of isolated middle cerebral arteries (MCAs) were assessed as indices of neurovascular and myogenic function, respectively, in 10-to 12-week control and type 2 diabetic Goto-Kakizaki rats. In addition, myogenic behavior of MCAs, nitrotyrosine (NY) levels, and VSM actin content were measured under normoxic and hypoxic [oxygen glucose deprivation (OGD)] conditions with and without the ONOO Ϫ decomposition catalyst 5,10,15,20-tetrakis(4-sulfonatophenyl) prophyrinato iron (III), chloride (FeTPPs). The percentage of myogenic tone was higher in diabetes, and forced dilation occurred at higher pressures. Functional hyperemia was impaired. Consistent with these findings, baseline CBF was lower in diabetes. OGD reduced the percentage of myogenic tone in both groups, and FeTPPs restored it only in diabetes. OGD increased VSM NY in both groups, and although FeTPPs restored basal levels, it did not correct the reduced filamentous/globular (F/G) actin ratio. Acute alterations in VSM ONOO Ϫ levels may contribute to hypoxic myogenic dysfunction, but this cannot be solely explained by the decreased F/G actin ratio due to actin nitration, and mechanisms may differ between control and diabetic animals. Our findings also demonstrate that diabetes alters the ability of cerebral vessels to regulate CBF under basal and hypoxic conditions.

Abstract. In this study, human MCF-7 breast cancer cells, which express functional estrogen and progesterone receptors, were used to compare the efficacy of combined antiestrogen plus antiprogestin therapy to antiestrogen monotherapy. Cells were treated with the antiestrogen 4-hydroxytamoxifen (4-OHT) and/or the antiprogestin mifepristone (MIF) and effects on cell proliferation (cytostatic action), cell cycle phase, the phosphorylation state of the tumor suppressor retinoblastoma protein (Rb), and induction of active cell death (cytotoxic action) were determined. Combination hormonal therapy showed both increased cytostatic and cytotoxic activity as compared to either monotherapy. The increased cytostatic action was mediated by Rb activation; whereas, the cytotoxic (pro-apoptotic) action of combined hormonal therapy correlated to a significant reduction in Rb protein levels. To test the apparent role of Rb protein loss in the pro-apoptotic action of combined hormonal therapy, Rb was downregulated in MCF-7 cells using siRNA-targeting. The siRNA-mediated knockdown of Rb combined with 4-OHT therapy resulted in a pro-apoptotic action similar to that resulting from 4-OHT and MIF combination treatment, which included increased cell detachment from the monolayer, high-molecular-weight genomic DNA fragmentation, and cleavage of poly ADP-ribose polymerase (PARP) and lamin A. From these studies, we conclude that Rb protein downregulation is required for 4-OHT-treated, estrogen receptor positive (ER + ) breast cancer cells to undergo active cell death. We discuss the potential of using an antiprogestin such as MIF plus antiestrogen treatment to more effectively downregulate Rb in ER + breast cancer cells to increase the overall cytotoxic action of hormonal therapy.

Purpose. Television watching has been reported to be associated with obesity, resting energy expenditure, and lower daily physical activity among both children and adolescents. However, most of these studies were based on self report or data collected in laboratory settings. This study examined the relationship among observed time of television watching, observed physical activity level and body composition among 3- or 4-year-old children. Methods. African-American (41.4%), Mexican-American (23%), and Anglo-American (35.6%) children (N = 191, males = 90) from the Texas site of the Studies of Child Activity and Nutrition program were observed from 6 to 12 hours per day up to 4 days over 1 year. Activity level each minute of the day was measured with the Children's Activity Rating Scale (interobserver reliability = .84 ± .001). The interobserver reliability of time of television watching was .96 ± .08. Results. The median of the longest number of consecutive minutes of television watching was 15 (range = 1 to 79). The median percent of minutes of television watching of total observed minutes was 14.8% (0% to 58%) and the median percent of minutes of inside minutes was 17.9% (0% to 80.9%). There were no gender or ethnic differences in time watching television or physical activity during television watching. Physical activity during television watching was lowest during the longest bout of television watching (\l=x_\ = 1.48 ± .28) compared to outside minutes (\l=x_\ = 2.38 ± .21), inside non-television minutes (\l=x_\ = 1.96 ± .13) and inside television minutes (\l=x_\ = 1.65 ± .18). The level of physical activity during television-watching times was highest (P <.0031) during October and November and lowest during March, April, June, and July. Longest bout of television watching and percent of minutes watching television to total observed minutes were inversely associated with mean physical activity, percent of minutes of physical activity levels 3, 4, or 5, and percent of physical activity levels 4 or 5. Percent of television watching to inside minutes was negatively correlated with physical activity levels 4 or 5. Television-watching behavior was not associated with body composition. Conclusions. Television watching was weakly negatively correlated with physical activity levels, and physical activity was lower during television-watching than non-television-watching time in this sample of children. Television viewing behavior was not associated with body composition.

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BackgroundAdmission hyperglycemia impacts ischemic stroke deleteriously but the relative role of acute hyperglycemia versus diabetes in the pathogenesis of this poor outcome is not clear.PurposeTo test the hypothesis that the impact of acute hyperglycemia on neurovascular damage following ischemic injury is more severe when superimposed on diabetes.MethodsAcute hyperglycemia (HG) was achieved by 3 ml IP glucose injection (300 mM) 20–30 minutes before 3 h middle cerebral artery occlusion (MCAO) in male control Wistar and mildly diabetic Goto‐Kakizaki (GK) rats. The goal was to achieve mild elevation in blood glucose levels (~180 mg/dl) in control rats to mimic glucose levels normally observed in the GK model. Following 21 h reperfusion neurobehavioral tests were performed before sacrifice and neuronal (infarct size) and vascular (hemorrhagic transformation (HT) frequency and excess hemoglobin) damage were measured.ResultsInfarct size was significantly smaller in diabetes. Moderate HG increased neuronal damage in diabetic but not in control rats. HT frequency and hemoglobin was significantly higher in diabetes. HG augmented vascular damage in control rats but had no additional effect on bleeding in diabetes. There was significant neurological deficit in diabetes which was worsened by HG.ConclusionsEven moderate hyperglycemia worsens outcome from ischemic stroke. While moderate HG does not increase infarct size in control rats, it is sufficient to induce HT. A further elevation in blood glucose in diabetic animals does not worsen HT suggesting that diabetic animals already suffer from increased vascular damage.