Pharmacokinetics of anthocyanidin-3-glycosides following consumption of Hibiscus sabdariffa L. extract

Pharmacokinetic parameters of several dietary anthocyanins following consumption of Hibiscus sabdariffa L. extract were determined in 6 healthy volunteers. Subjects were given a single oral dose of 150 mL of Hibiscus sabdariffa L. extract yielding 62.6 mg of cyanidin-3-sambubioside, 81.6 mg of delphindin-3-sambubioside, and 147.4 mg of total anthocyanins (calculated as cyanidin equivalents). Within 7 hours, the urinary excretion of cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins (ie, the sum of all quantifiable anthocyanidin glycosides) was 0.016%, 0.021%, and 0.018% of the administered doses, respectively. Maximum excretion rates were determined at 1.5 to 2.0 hours after intake. The dose-normalized plasma area under the curve estimates were 0.076, 0.032, and 0.050 ng x h/mL/mg for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The dose-normalized C(max) estimates were 0.036, 0.015, and 0.023 ng/mL/mg in the same sequence. They were reached each at 1.5 hours (median) after intake. The geometric means of t1/2 were 2.18, 3.34, and 2.63 hours for cyanidin-3-sambubioside, delphinidin-3-sambubioside, and total anthocyanins, respectively. The urinary excretion of intact anthocyanins was fast and appeared to be monoexponential. To evaluate the contribution of anthocyanins to the health-protecting effects of Hibiscus sabdariffa L. extract, it will be necessary to perform further studies on both the intact glycosides and their in vivo metabolites or conjugates in human plasma and urine.     

Inhibition of erythrocyte “apoptosis” by catecholamines

Osmotic shock, oxidative stress and Cl⁻ removal activate a non-selective Ca²⁺-permeable cation conductance in human erythrocytes. The entry of Ca²⁺ leads to activation of a scramblase with subsequent exposure of phosphatidylserine at the cell surface. Phosphatidylserine mediates binding to phosphatidylserine receptors on macrophages which engulf and degrade phosphatidylserine exposing cells. Moreover, phosphatidylserine exposure may lead to adherence of erythrocytes to the vascular wall. In the present study, we explored whether activation of the non-selective cation conductance and subsequent phosphatidylserine exposure might be influenced by catecholamines. Phosphatidylserine exposure has been determined by FITC-annexin V binding while cell volume was estimated from forward scatter in FACS analysis. Removal of Cl⁻ enhanced annexin binding and decreased forward scatter, an effect significantly blunted by the β agonist isoproterenol (IC₅₀ approx. 1 μM). Fluo-3 fluorescence measurements revealed an increase of cytosolic Ca²⁺ activity following Cl⁻ removal, an effect again significantly blunted by isoproterenol exposure (10 μM). Whole-cell patch-clamp experiments performed in Cl⁻ free bath solution indeed disclosed a time-dependent inactivation of a non-selective cation conductance following isoproterenol exposure (10 μM). Phenylephrine (IC₅₀<10 μM), dobutamine (IC₅₀ approx. 1 μM) and dopamine (IC₅₀ approx. 3 μM) similarly inhibited the effect of Cl⁻ removal on annexin binding and forward scatter. In conclusion, several catecholamines inhibit the Cl⁻ removal-activated Ca²⁺ entry into erythrocytes, thus preventing increase of cytosolic Ca²⁺ activity, subsequent cell shrinkage and activation of erythrocyte scramblase. The catecholamines thus counteract erythrocyte phosphatidylserine exposure and subsequent clearance of erythrocytes from circulating blood.     

Follow-up of abnormal or inadequate cervical smears using two guidance systems: RCT on effectiveness

BACKGROUND: To improve follow-up compliance after an initial inadequate or abnormal cervical smear, two follow-up guidance systems were tested for effectiveness. A comprehensive system (cytopathology laboratory monitored the follow-up of all abnormal and inadequate smears) was compared to a selective system (monitoring was left to the smear taker; laboratory acted as a safety net). METHODS: In an RCT on all family practices (N = 171) in the catchment areas of two cytopathology laboratories (Nijmegen region, The Netherlands, 1998-2000), practices were allocated at random to one of the follow-up guidance systems. All women included were registered at the practices, invited to the national screening program and had abnormal or inadequate smears. Measurements comprised of (1) follow-up compliance at baseline and 1 year after the initial smear and (2) diagnostic outcome of the follow-up smear. RESULTS: During the study period, 132 practices sent their cervical smears to the laboratories. The comprehensive system covered 1226 women, the selective 1034. In the comprehensive system, the increase in follow-up compliance for initial inadequate and slightly abnormal smears was significantly higher (8.9%) than in the selective one, which implied an extra detection of eleven, more serious, abnormalities per 1000 women. CONCLUSION: The comprehensive system was more effective than the selective and is suitable for use on a larger scale.     

Human tonsil implants xenotransplanted in SCID mice display broad lymphocytic diversity and cellular activation profile similar to those in the original lymphoid organ

BACKGROUND: Models consisting of human immune cells in suspension transferred to severe combined immune deficient (SCID) mice have been invaluable for studying immune response, autoimmunity, and lymphomagenesis. The dissemination of human cells within the mouse body hampers immune functionality with time and favorites the development of human graft vs. mouse host (GvH) disease. To circumvent these limitations we surgically implanted tonsil pieces subcutaneously in SCID animals (hu-ton-SCID mice). Recall humoral responses was elicited and animals did not suffer from signs of GvH disease. A detailed cell subset and cell activation analysis of implants has not yet been reported. METHODS: Implants from 86 hu-ton-SCID mice were evaluated by immunohistochemistry and flow cytometry analyses to assess human lymphoid cell subpopulation surviving with time after implantation, and to evaluate status of human cell activation. Results: B cells persist over 3 months in implants. The proportion of class and type-specific Ig+ cells varied between implants, but as a whole IgG+ cells were more abundant than IgA+, and IgM+ cells, and kappa+ cells predominated over lambda+ cells. The mean proportions of these cells resemble those in the original tonsil. Fine analysis of CD19+ B cells demonstrated no expansion of activated (CD5+, CD23+, CD69+) B cells in implants compared with tonsils, and a decrease of CD19+CD77+ B cells corresponding to a centroblastic phenotype, which is consistent with the disappearance of follicular structure in implants. Double positive CD20+CD27+ memory B cells were detected in implants by immunohistochemistry. T cell CD4+CD8-/CD4-CD8+ ratios were about 4 in implants, that is similar to those in tonsils, and there was no expansion of CD3+CD4+CD8+ and of CD3+CD4-CD8- T-cell subpopulations. T cells activation markers (CD25, CD69) were similarly expressed in implants and tonsils, and implants contained cells with a memory T cell phenotype (CD45RO). Finally cells within implants depicted a low rate of proliferation when assessed by Ki-67 expression levels. Conclusions: Compared with original tonsils, tonsil implants in hu-ton-SCID mice lose the germinal center architecture, which is correlated with the decrease of CD77+ B cells, but conserve T and B cell subpopulation diversity, notably memory cells. In addition, implant T and B cells are not differently activated when compared with those in original tonsils and do not proliferate extensively. These observations indicate indirectly absence of GvH reaction at the cellular level in this model. Collectively, the detailed implant cellular characterization in the hu-ton-SCID model provides a strong rationale for the use of this model in the study of human recall antibody response.     

Etiology and epidemiology of end-stage renal disease in Dutch children 1987–2001

In this retrospective study 351 children (<16.0 years) with end-stage renal disease (ESRD) accepted for renal replacement therapy (RRT) in the four Dutch pediatric centers were analyzed for the period 1987–2001. The data were compared with a previous study performed in 1979–1986. Eighty patients were of non-Dutch origin. An annual ESRD incidence of 5.8 patients per million of the child population (p.m.c.p.) was calculated, without significant changes with time. The final prevalence in Dutch children under 15 years of ESRD was 38.7 p.m.c.p. The most frequent primary renal disease leading to ESRD was urethral valves, with a significant increase vs. the previous observation period (14% vs. 6%). The distribution of primary renal diseases was similar in patients of non-Dutch origin and in Dutch patients. Peritoneal dialysis was the most frequent dialysis procedure initially applied (62% vs. 26% in the earlier observation period). Thirteen percent of all first transplantations (n=278) were pre-emptive and 19% from living donors. Five-year graft survival after a living-donor and a cadaver graft was 80% and 73%, respectively. Overall patient survival after 10 years on RRT was 94%.     

Differential immunogenicity of HLA mismatches in clinical transplantation

Although HLA matching is beneficial in clinical transplantation, it is not feasible to select a completely HLA matched donor for every potential recipient because of the enormous polymorphism of the HLA system. As a consequence, the majority of the recipients will be transplanted with a mismatched donor organ or hematopoietic stem cell transplant. For this large group of patients it is important to take advantage of the differential immunogenicity of HLA mismatches and to select for them a donor with HLA mismatches of low immunogenicity, the so-called acceptable mismatches. The differential immunogenicity of HLA mismatches can be determined by either retrospective analysis of graft survival data or by in vitro assays measuring T-cell and B-cell alloreactivity. A recently developed computer algorithm (HLAMatchmaker) can be instrumental in selecting donors with HLA mismatches, which do not lead to alloantibody formation. The theoretical background and practical implications of this acceptable mismatch approach are discussed.     

Variability in clinical laboratory practice in testing for disorders of platelet function: results of two surveys of the North American Specialized Coagulation Laboratory Association

Disorders of platelet function are important causes of abnormal bleeding that require laboratory tests for diagnosis. Currently there are limited guidelines on how to perform clinical testing for these disorders. The goal of our study was to obtain information on how disorders of platelet function are currently evaluated in clinical laboratories. Two patterns-of-practice surveys were distributed to laboratories of the North American Specialized Coagulation Laboratory Association (NASCOLA). The information collected was analyzed to determine practices and common problems. Forty-seven NASCOLA laboratories participated and 54% completed both surveys. The majority of the laboratories that responded performed more than 50 aggregation tests per year, mainly using platelet rich plasma based methodologies. A minority performed testing for platelet secretion and dense granule abnormalities. While platelet aggregation results were reviewed in various ways, laboratories most commonly issued a combined report containing quantitative values (% aggregation and/or slope) and a qualitative interpretation. Although laboratories used similar agonists for aggregation testing, the final agonist concentrations varied widely. Several approaches were also used to obtain reference intervals. Comments offered by the participants indicated that performing, and interpreting platelet function tests were challenging for many clinical laboratories. Although common practices have evolved, there is considerable variability in the diagnostic test procedures used by clinical laboratories to evaluate disorders of platelet function. These patterns-of-practice surveys illustrate a need for guidelines and recommendations for clinical laboratories performing tests of platelet function.     

Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis of randomized controlled trials

PURPOSE: Coffee is a widely consumed beverage and small health effects of substances in coffee may have large public health consequences. It has been suggested that caffeine in coffee increases the risk of hypertension. We performed a meta-analysis of randomized controlled trials of coffee or caffeine and blood pressure (BP). DATA IDENTIFICATION: BP trials of coffee or caffeine published between January 1966 and January 2003 were identified through literature databases and manual search. STUDY SELECTION: A total of 16 studies with a randomized, controlled design and at least 7 days of intervention was selected, comprising 25 strata and 1010 subjects. DATA EXTRACTION: Two persons independently obtained data on sample size, type and duration of intervention, changes in BP and heart rate (HR), and subjects' characteristics for each trial. Meta-analysis was performed using a random-effects model. RESULTS: A significant rise of 2.04 mmHg [95% confidence interval (CI), 1.10-2.99] in systolic BP and 0.73 mmHg (95% CI, 0.14-1.31) in diastolic BP was found after pooling of coffee and caffeine trials. When coffee trials (n = 18, median intake: 725 ml/day) and caffeine trials (n = 7, median dose: 410 mg/day) were analysed separately, BP elevations appeared to be larger for caffeine [systolic: 4.16 mmHg (2.13-6.20); diastolic: 2.41 mmHg (0.98-3.84)] than for coffee [systolic: 1.22 mmHg (0.52-1.92) and diastolic: 0.49 mmHg (-0.06-1.04)]. Effects on HR were negligible. CONCLUSIONS: Regular caffeine intake increases BP. When ingested through coffee, however, the blood pressure effect of caffeine is small.     

Differential roles of fibroblast growth factor-2 during development and maintenance of auditory sensory epithelia

Fibroblast growth factor-2 (FGF2) has been postulated to be a key regulator involved in the proliferation, differentiation, and regeneration of sensory hair cells. Here we have addressed the potential functions of FGF2 during the formation and regeneration of the auditory epithelium in chicken and mice. By using viral gene transfer, based on herpes simplex type 1 virus (HSV-1), we show that ectopically applied FGF2 drastically increases the number of cells expressing early hair cell markers during embryonic development in avians. Intriguingly, FGF2 does not stimulate cell division during this process. These data suggest that FGF2 plays a role during differentiation of sensory hair cells in avians. To address the potential functions of FGF2 during murine inner ear development, we analyzed FGF2 mouse mutants. Mice lacking FGF2 showed normal formation of the inner ear, and no abnormalities were observed at the adult stage. Moreover, FGF2 mouse mutants showed similar hearing thresholds compared with those observed in control mice before and after noise damage. Therefore, endogenous FGF2 appears not to be essential for the development or functional maintenance of the auditory organ in mammals. In light of these results, the differential roles of FGF2 in the vertebrate inner ear are discussed with respect to its previously postulated functions.