Pharmacokinetics of anthocyanins and ellagic acid in healthy volunteers fed freeze-dried black raspberries daily for 7 days

Eleven subjects completed a clinical trial to determine the safety/tolerability of freeze-dried black raspberries (BRB) and to measure, in plasma and urine, specific anthocyanins-cyanidin-3-glucoside, cyanidin-3-sambubioside, cyanidin-3-rutinoside, and cyanidin-3-xylosylrutinoside, as well as ellagic acid. Subjects were fed 45 g of freeze-dried BRB daily for 7 days. Blood samples were collected predose on days 1 and 7 and at 10 time points postdose. Urine was collected for 12 hours predose on days 1 and 7 and at three 4-hour intervals postdose. Maximum concentrations of anthocyanins and ellagic acid in plasma occurred at 1 to 2 hours, and maximum quantities in urine appeared from 0 to 4 hours. Overall, less than 1% of these compounds were absorbed and excreted in urine. None of the pharmacokinetic parameters changed significantly between days 1 and 7. In conclusion, 45 g of freeze-dried BRB daily are well tolerated and result in quantifiable anthocyanins and ellagic acid in plasma and urine.     

Safety and efficacy of reoperative carotid endarterectomy: a 14-year experience

BACKGROUND: Reoperative carotid endarterectomy (CEA) is an accepted treatment for recurrent carotid stenosis. With reports of a higher operative morbidity than primary CEA and the advent of carotid stenting, catheter-based therapy has been advocated as the primary treatment for this reportedly "high-risk" subgroup. This study reviews a contemporary experience with reoperative CEA to validate the high-risk categorization of these patients. METHODS: From 1989 to 2002, 153 consecutive, isolated (excluding CEA/coronary artery bypass graft and carotid bypass operations) reoperative CEA procedures were reviewed. Clinical and demographic variables potentially associated with the end points of perioperative morbidity, long-term durability, and late survival were assessed with multivariate analysis. RESULTS: There were 153 reoperative CEA procedures in 145 patients (56% men, 36% symptomatic) with an average age of 69 +/- 1.3 years. The average time from primary CEA (68% primary closure, 23% prosthetic, 9% vein patch) to reoperative CEA was 6.1 +/- 0.4 years (range, 0.3 to 20.4 years). At reoperation, patch reconstruction was undertaken in 93% of cases. The perioperative stroke rate was 1.9%, with no deaths or cardiac complications. Other complications included cranial nerve injury (1.3%) and hematoma (3.2%). Average follow-up after reoperative CEA was 4.4 +/- 0.3 years (range, 0.1 to 12.7 years), with an overall total stroke-free rate of 96% and a restenosis rate (>50%) by carotid duplex of 9.2%. Among variables assessed for association with restenosis after reoperative CEA, only younger age was found to be significant (66 +/- 2.5 years vs 70 +/- 0.7 years, P < .05). The all-cause long-term mortality rate was 29%. Multivariate analysis of long-term survival identified diabetes mellitus as having a negative impact (hazard ratio, 3.4 +/- 0.3, P < .05) and lipid-lowering agents as having a protective effect (hazard ratio, 0.42 +/- 0.4, P < .05) on survival. CONCLUSION: Reoperative CEA is a safe and durable procedure, comparable to reported standards for primary CEA, for long-term protection from stroke. These data do not support the contention that patients who require reoperative CEA constitute a "high-risk" subgroup in whom reoperative therapy should be avoided.     

Polyadenosine diphosphate-ribose polymerase inhibition modulates skeletal muscle injury following ischemia reperfusion

HYPOTHESIS: Polyadenosine diphosphate-ribose polymerase (PARP) has been implicated as a mediator of inflammation and tissue necrosis in murine models of human stroke and myocardial infarction. This study was designed to determine whether PARP modulates skeletal muscle injury and cytokine-growth factor levels during ischemia-reperfusion. DESIGN: Prospective controlled animal study. SETTING: Medical school-affiliated university hospital. INTERVENTIONS: Mice were divided into 2 groups-treated (PJ) and untreated; all mice were subjected to unilateral hind limb tourniquet ischemia followed by 4 or 48 hours of reperfusion. In treated mice, PJ34, an ultrapotent-specific PARP inhibitor was given immediately before ischemia and prior to reperfusion. A group of PARP-1 knockout mice (PARP-/-) were also subjected to hind limb ischemia followed by 48 hours of reperfusion. MAIN OUTCOME MEASURES: After ischemia-reperfusion, muscle was harvested for measurement of edema, viability, cytokine, and vascular endothelial growth factor content. RESULTS: The PJ34-treated mice had increased skeletal muscle viability when compared with the untreated mice after 4 and 48 hours of reperfusion (P<.01). Viability between PARP-/- and PJ34-treated mice were similar at 48 hours of reperfusion (P>.05), and it exceeded that of untreated mice (P<.01). Tissue edema was unaltered by PARP inhibition. Tissue levels of cytokine were only different (P<.05) in PJ34-treated vs untreated mice at 48 hours of reperfusion. Vascular endothelial growth factor levels in PJ34-treated mice were markedly reduced when compared with untreated mice only after 4 hours of reperfusion (P<.01), and in PARP-/- mice (P<.01) at 48 hours of reperfusion. CONCLUSIONS: Polyadenosine diphosphate-ribose polymerase modulates skeletal muscle viability, cytokine and vascular endothelial growth factor synthesis during reperfusion. Polyadenosine diphosphate-ribose polymerase inhibition may represent a novel method to modulate skeletal muscle ischemia-reperfusion injury.     

Chemopreventive effects of a selective nitric oxide synthase inhibitor on carcinogen-induced rat esophageal tumorigenesis

The inducible nitric oxide synthase (iNOS) generates a high concentration of nitric oxide (NO) in tissues. Increased NO production is associated with many disorders including esophageal cancer. Previous studies in our laboratory demonstrated an association between increased iNOS expression and the development of N-nitrosomethylbenzylamine (NMBA)-induced tumors in the rat esophagus. On the basis of these observations, we initiated a bioassay to evaluate the ability of S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT), a selective iNOS inhibitor, to prevent the progression of esophageal tumors in rats preinitiated with NMBA. Rats were given s.c. injections of NMBA (0.25 mg/kg body weight) three times per week for 5 weeks. One week later, they were fed a synthetic diet containing either 50 or 100 ppm PBIT until the end of the bioassay (25 weeks). PBIT reduced the incidence of esophageal cancer from 96% in NMBA-treated rats to 83% and 77% (P < 0.05) in rats treated with 50 and 100 ppm PBIT, respectively. Tumor multiplicity was reduced from 3.64 +/- 0.42 tumors per esophagus in NMBA-treated rats to 1.79 +/- 0.25 (P < 0.001) and 1.50 +/- 0.24 (P < 0.0001) in rats treated with 50 and 100 ppm PBIT, respectively. PBIT reduced the production of NO in NMBA-induced preneoplastic and papillomatous esophageal lesions when compared with comparable lesions in rats treated with NMBA only. iNOS mRNA expression was not modulated by PBIT. These observations suggest that iNOS plays a role in tumor development and that its selective inhibitor, PBIT, significantly inhibits esophageal tumor progression presumably through reducing the production of NO.     

Integrated oral bioavailability projection using in vitro screening data as a selection tool in drug discovery

The objective of the analysis described herein is to examine the in vitro/in vivo relationship of estimated bioavailability values and also the applicability of the estimated in vitro bioavailability to lead candidate selection in drug discovery. To this end, in vitro ADME data from screening assays as well as in vivo rat pharmacokinetic (PK) data were compiled for 140 compounds across therapeutic areas from the Pfizer library in Ann Arbor. The compounds span a broad range of structural types, including neutral, basic, and acidic compounds. Solubility and Caco-2 permeability data from in vitro ADME screening were used to calculate the fraction dose absorbed (FDp) using the physiologically based IDEA model. In vitro metabolic stability (t(1/2)) from human and rat liver microsomal incubations was converted to an in vitro intrinsic clearance value (CL(int)'), which was then scaled up to reflect in vivo clearance (CL) and hepatic extraction as described by Obach et al. [J. Pharmcol. Exp. Ther. 283 (1997) 46]. Subsequently, the in vitro/in vivo relationship between the measured bioavailability (F(obs)) in rats and the estimated bioavailability (F(est)) from FDp and predicted CL values was examined. The observed data suggest that compounds with low estimated in vitro bioavailability (F(est)<15%) are more likely to have low in vivo bioavailability (F(obs)<30%). Therefore, the present study indicates that in vitro estimation of bioavailability is an efficient tool to eliminate compounds having low bioavailability prior to in vivo characterization and therefore can be used to reduce attrition due to poor ADME properties in drug development.     

Attentional selection of superimposed surfaces cannot be explained by modulation of the gain of color channels

When two differently colored, superimposed patterns of dots rotate in opposite directions, this yields the percept of two superimposed transparent surfaces. If observers are cued to attend to one set of dots, they are impaired in making judgments about the other set. Since the two sets of dots are overlapping, the cueing effect cannot be explained by spatial attention. This has led to the interpretation that the impairment reflects surface-based attentional selection. However, recent single-unit recording studies in monkeys have found that attention can modulate the gain of neurons tuned for features such as color. Thus, rather than reflecting the selection of a surface, the behavioral effects might simply reflect a reduction in the gain of color channels selective for the color of the uncued set of dots (feature-based attention), as if viewing the surfaces through a colored filter. If so, then the impairment should be eliminated when the two surfaces are made the same color. Instead, we find that the impairment persists with no reduction in strength. Our findings thus rule out the color gain explanation.     

Exogenously cued attention triggers competitive selection of surfaces

It has been reported that when an endogenous cue directs attention to a brief translation of one of two superimposed surfaces, observers reliably report the direction of that translation as well as the direction of a second translation of the cued surface. In contrast, if the uncued surface translates second, direction judgments are severely impaired for several hundred milliseconds. We replicated this result, but found that the impairment survived the removal of the endogenous cue. The impairment is therefore not due to endogenously cued attention. Instead, a brief translation of one surface acts as an exogenous cue that triggers an automatic selection mechanism, which suppresses processing of the other surface. This study provides a clear case of exogenous cueing of surface-based attention. We relate these results to identified competitive selection mechanisms in visual cortex.