Correlation between miR-1207-5p expression with steroid-induced necrosis of femoral head and VEGF expression.

OBJECTIVE: The aim of this study was to investigate the expression level of micro-ribonucleic acid-1207-5p (miR-1207-5p) in steroid-induced necrosis of femoral head (SNFH) and its correlation with SNFH. Meanwhile, we also aimed to analyze the relationship between miR-1207-5p expression and vascular endothelial growth factor (VEGF) in the femoral head. PATIENTS AND METHODS: From May 2016 to December 2017, 60 patients aged (55.4±8.7) were selected in our hospital. All patients were diagnosed and confirmed as SNFH. Total RNA was extracted from the necrotic femoral head tissues and peripheral blood. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used to detect the expression level of miR-1207-5p in tissues. At the same time, immunohistochemistry and Western blotting were adopted to detect VEGF expression in the bone tissue of patients with high or low expression of miR-1207-5p. 7 patients with femoral neck fracture aged (45.6±4.51) were enrolled in the control group. In the animal experiment, the rat SNFH model was established by intraperitoneal injection of lipopolysaccharide and methylprednisolone. Subsequently, the expression levels of miR-1207-5p and VEGF in necrotic femoral tissues were detected. Meanwhile, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was applied to detect cell apoptosis in bone lacunae of miR-1207-5p high expression group and miR-1207-5p low expression group, respectively. RESULTS: The expression level of miR-1207-5p in the necrotic bone tissue of the SNFH group was significantly higher than that of the control group. The expression level of miR-1207-5p was inversely proportional to Harris Hip score (p<0.05). A higher expression of miR-1207-5p indicated a lower expression level of VEGF (p<0.05). The animal experimental results revealed that miR-1207-5p expression in the necrotic femoral head tissue of SNFH group was significantly higher than that of the control group. Furthermore, the number of apoptotic cells in bone lacunae was remarkably higher in miR-1207-5p high expression group (p<0.05). CONCLUSIONS: MiR-1207-5p is significantly up-regulated in necrotic femoral head tissue and serum of SNFH patients. Meanwhile, its expression level is inversely proportional to Harris Hip score of patients. The possible underlying mechanism may be related to the inhibitory effect of miR-1207-5p on VEGF.

Monitoring liver function among patients who initiated anti-tuberculosis drugs in Taiwan, 2000-2011.

OBJECTIVE: To investigate adherence to liver function monitoring as recommended in Taiwan's tuberculosis (TB) diagnosis and treatment guidelines for newly diagnosed TB patients. DESIGN: Retrospective cohort study of the National Health Insurance Research Database (NHIRD), Taiwan, 2000-2011. METHODS: From the NHIRD, we identified 11 397 newly diagnosed TB patients who initiated anti-tuberculosis treatment between 2000 and 2011 and categorised these into three groups: completely, partially and non-adherent. Logistic regression was used to explore potential factors associated with the adherence rate. RESULTS: The completely adherent rate increased from 0.5% in 2000 to 9.2% in 2011, while the non-adherent rate decreased from 17.5% to 1.2%. Compared to the non-adherent group, patients with a history of liver disease (OR 4.36, 95%CI 1.92-9.87) and viral hepatitis (OR 9.39, 95%CI 1.47-60.19), as well as patients whose prescribing physicians were specialists in chest (OR 4.59, 95%CI 1.91-11.05), TB (OR 2.55, 95%CI 1.01-6.40) and infectious diseases (OR 3.93, 95%CI 1.08-14.31), had higher odds of being completely adherent to the guidelines. CONCLUSION: Our findings could serve as an important reference for developing effective strategies to improve adherence to guidelines and prevent patients from developing anti-tuberculosis drug-associated hepatotoxicity.

Potential modulation on P-glycoprotein and CYP3A by soymilk and miso: in vivo and ex-vivo studies.

P-glycoprotein (P-gp) and CYP3A4 both play very important roles in drug bioavailability, resistance and interactions. Our in vitro studies indicated that P-gp function was activated by many isoflavones. This study investigated the in vivo effects of soymilk and miso, isoflavone-rich soy foods, on P-gp and CYP3A by tracing the pharmacokinetics of cyclosporine (CSP), a probe drug of P-gp. Rats were orally administered CSP with and without soymilk or miso. A specific monoclonal fluorescence polarisation immunoassay was used to determine the blood concentration of CSP. The results showed that soymilk and miso significantly decreased the C(max) of CSP by 64.5% and 78.3%, and reduced the AUC(0-540) by 64.9% and 78.3%, respectively. Mechanism studies revealed that the activities of P-gp and CYP3A4 were induced by soymilk and miso. In conclusion, ingestion of soymilk and miso significantly activated the functions of P-gp and CYP3A.

Inhibitive effects of mulberry leaf-related extracts on cell adhesion and inflammatory response in human aortic endothelial cells.

Effects of mulberry leaf-related extracts (MLREs) on hydrogen peroxide-induced DNA damage in human lymphocytes and on inflammatory signaling pathways in human aortic endothelial cells (HAECs) were studied. The tested MLREs were rich in flavonols, especially bombyx faces tea (BT) in quercetin and kaempferol. Polyphenols, flavonoids, and anthocyanidin also abounded in BT. The best trolox equivalent antioxidant capacity (TEAC) was generated from the acidic methanolic extracts of BT. Acidic methanolic and water extracts of mulberry leaf tea (MT), mulberry leaf (M), and BT significantly inhibited DNA oxidative damage to lymphocytes based on the comet assay as compared to the H2O2-treated group. TNF- α -induced monocyte-endothelial cell adhesion was significantly suppressed by MLREs. Additionally, nuclear factor kappa B (NF- κ B) expression was significantly reduced by BT and MT. Significant reductions were also observed in both NF- κ B and activator protein (AP)-1 DNA binding by MLREs. Significant increases in peroxisome proliferator-activated receptor (PPAR) α and γ DNA binding by MLREs were also detected in M and MT extracts, but no evidence for PPAR α DNA binding in 50 µ g/mL MT extract was found. Apparently, MLREs can provide distinct cytoprotective mechanisms that may contribute to its putative beneficial effects on suppressing endothelial responses to cytokines during inflammation.

Tuberculosis in myasthenia gravis.

SETTING: The relationship between myasthenia gravis (MG) and tuberculosis (TB) has not been determined. OBJECTIVE: To evaluate the relationship between MG and TB. DESIGN: A national survey conducted between 2000 and 2006 included 2317 patients with MG identified from the Taiwan National Health Insurance database. The incidence rate ratio of TB in these patients was compared with those in 23 170 randomly selected age-, sex- and comorbidity-matched controls without MG. RESULTS: The risk of TB was higher in the MG cohort (adjusted hazard ratio [aHR] 1.96, 95% confidence interval [CI] 1.22-3.16, P = 0.005), mainly due to an excess risk of pulmonary TB (aHR 2.10, 95%CI 1.27-3.47, P = 0.004). Age ≥60 years (HR 4.99, 95%CI 2.06-12.10, P < 0.001) and the use of corticosteroids (HR 1.12, 95%CI 1.07-1.17, P < 0.001) were risk factors for developing TB in the MG cohort. Patients with MG who developed TB had a lower 5-year survival rate than those who did not (89.4% vs. 96.0%, P = 0.032). CONCLUSION: The incidence of pulmonary TB is significantly higher in patients with MG. Careful screening strategies for TB should be considered among high-risk patients with MG.

Dosimetric advantages of generalised equivalent uniform dose-based optimisation on dose-volume objectives in intensity-modulated radiotherapy planning for bilateral breast cancer.

OBJECTIVE: We compared and evaluated the differences between two models for treating bilateral breast cancer (BBC): (i) dose-volume-based intensity-modulated radiation treatment (DV plan), and (ii) dose-volume-based intensity-modulated radiotherapy with generalised equivalent uniform dose-based optimisation (DV-gEUD plan). METHODS: The quality and performance of the DV plan and DV-gEUD plan using the Pinnacle(3) system (Philips, Fitchburg, WI) were evaluated and compared in 10 patients with stage T2-T4 BBC. The plans were delivered on a Varian 21EX linear accelerator (Varian Medical Systems, Milpitas, CA) equipped with a Millennium 120 leaf multileaf collimator (Varian Medical Systems). The parameters analysed included the conformity index, homogeneity index, tumour control probability of the planning target volume (PTV), the volumes V(20 Gy) and V(30 Gy) of the organs at risk (OAR, including the heart and lungs), mean dose and the normal tissue complication probability. RESULTS: Both plans met the requirements for the coverage of PTV with similar conformity and homogeneity indices. However, the DV-gEUD plan had the advantage of dose sparing for OAR: the mean doses of the heart and lungs, lung V(20) (Gy), and heart V(30) (Gy) in the DV-gEUD plan were lower than those in the DV plan (p<0.05). CONCLUSIONS: A better result can be obtained by starting with a DV-generated plan and then improving it by adding gEUD-based improvements to reduce the number of iterations and to improve the optimum dose distribution. Advances to knowledge The DV-gEUD plan provided superior dosimetric results for treating BBC in terms of PTV coverage and OAR sparing than the DV plan, without sacrificing the homogeneity of dose distribution in the PTV.

Quantification of macrovesicular and microvesicular hepatic steatosis in rats using 3.0-T ¹H-magnetic resonance spectroscopy.

BACKGROUND AND OBJECTIVE: Hepatic steatosis (HE), which is common among the general population, is present in donor organs, potentially affecting their graft survival as well as the recovery of the donor. Our goal was to develop an experimentally and clinically reliable, noninvasive method to quantify macrovesicular and microvesicular hepatic steatosis using 3-T (1)H-magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS: Macrovesicular and microvescular steatosis were induced in rats using methylcholine deficiency and choline deficiency diets. A MayoBC10 coil was used for radiofrequency transmission and signal recept. Measurements of hepatic fat content were performed using (1)H spectroscopy on a 3.0-T whole-body GE Signa system. The ratio of the areas under the curve of fat (0.8-1.3 ppm) and water (4.7 ppm) was used to determine hepatic fat content, which was compared with the degree of histopathologic and biochemical steatosis. RESULTS: Twenty rats were divided into two groups based on the percentage of microvesicular liver steatosis. Group A (n = 13) was the lower percentage group (microvesicular < 10%) while group B (n = 7), the higher group (microvesicular ≥ 10%). The mean total fatty change in the liver was 58.4% ± 47.2% and 67.6% ± 39.1% in groups A and B, respectively. A highly significant linear correlation between (1)H-MRS and total fatty change was observed in group A (r = .986, P < .001) while there was a relatively poor correlation in group B (r = .764, P = .05). The power to predict fatty change in the liver in groups A and B was significantly different (P = .004). CONCLUSIONS: The degree of hepatic steatosis with a small amount of microvesicular steatosis (<10%) can be precisely predicted using 3-T (1)H-MRS.

Dual arc volumetric-modulated arc radiotherapy (VMAT) of nasopharyngeal carcinomas: a simultaneous integrated boost treatment plan comparison with intensity-modulated radiotherapies and single arc VMAT.

AIMS: To compare the performance of volumetric-modulated arc radiotherapy (VMAT) by dual arc with fixed beam intensity-modulated radiotherapies (IMRTs) and single arc VMAT on nasopharyngeal carcinomas (NPC). MATERIALS AND METHODS: Twenty NPC cases were re-planned using the planning system of the Pinnacle(3®)SmartArc (SA) module to compare the performance of the following four techniques: seven-field (7F) and 18-field (18F) fixed beam IMRT, and single (SA(1)) and dual arc VMAT (SA(2)). The plan was delivered on an Elekta Synergy™ Linac equipped with an 80-leaf 1cm multileaf collimator. Three dose levels of planning target volumes (PTVs) with 70/59.4/54.0Gy in 33 fractions were prescribed and delivered as a simultaneous integrated boost. The conformity index and homogeneity index of the PTVs, the comprehensive quality index (CQI), the normal tissue complication probability for the organs at risk (OARs), and the planning time, delivery efficiency and accuracy were analysed. RESULTS: A significantly inferior conformity index at the three dose levels of PTV and homogeneity index of PTV(70) were observed in SA(1) compared with the other techniques. Comparable conformity index and homogeneity index of the PTV were observed among 7F/18F IMRT and SA(2). Based on the CQI of the 11 OARs, the most efficient dose reduction was observed in 18F IMRT followed in order by SA(2), 7F IMRT and SA(1). The planning time was on average 13.2/24.9/40.1/42.8min for 7F/18F IMRT/SA(1)/SA(2), respectively. With regards to the delivery efficiency compared with 7F IMRT, a 51 and 41% reduction in delivery time was achieved by SA(1) and SA(2), respectively. All techniques presented a high quality assurance pass rate (>98%) of the Γ(3mm,3%) criterion. CONCLUSION: In NPC cases, SA(2) gave superior results in terms of PTV coverage and OAR sparing compared with SA(1) and approached the performance achieved by 18F IMRT, but without sacrificing the delivery efficiency.

Skin-homing CD4+ Foxp3+ T cells exert Th2-like function after staphylococcal superantigen stimulation in atopic dermatitis patients.

BACKGROUND: The effect of staphylococcal superantigens (SsAgs) on cutaneous lymphocyte-associated antigen (CLA)(+) CD4(+) Foxp3(+) T cells of atopic dermatitis (AD) patients is unknown. OBJECTIVE: To compare the effects of SsAgs on the ratio, function, and apoptosis of CCR6(+) subtype and CCR6(-) subtype of CLA(+) CD4(+) Foxp3(+) T cells among AD patients, asthma/allergic rhinitis (AR) patients without AD, and healthy subjects. METHODS: Using immunofluorescence staining followed by flow cytometric analysis, we analysed peripheral blood mononuclear cells cultured with or without staphylococcal enterotoxin B (SEB) stimulation in 20 AD patients, 20 asthma/AR patients without AD, and 20 healthy subjects. RESULTS: SEB decreased CCR6(+) /CCR6(-) ratio in CLA(+) CD4(+) Foxp3(+) T cells from AD patients and increased CCR6(+) /CCR6(-) ratio in those from healthy subjects. SEB induced the production of type 2 T helper cell (Th2) cytokine interleukin (IL)-5 in CCR6(-) subtype and anti-inflammatory cytokine IL-10 in CCR6(+) subtype of CLA(+) CD4(+) Foxp3(+) T cells. CLA(+) CD4(+) Foxp3(+) T cells from AD patients produced more IL-5 and less IL-10 after SEB stimulation than those from healthy subjects. CCR6(-) subtype of CLA(+) CD4(+) Foxp3(+) T cells from AD patients and CCR6(+) subtype of those cells from healthy subjects were more resistant to SEB-induced caspase-3 activation than the other subtype and those from other subjects. CONCLUSIONS AND CLINICAL RELEVANCE: Despite a phenotype of regulatory T cells, skin-homing CD4(+) Foxp3(+) T cells of AD patients exert effector Th2-like function after SsAgs stimulation, which may aggravate allergic skin inflammation.

Anti-inflammatory effects of pioglitazone on iron-induced oxidative injury in the nigrostriatal dopaminergic system.

AIMS: Transition metals, oxidative stress and neuroinflammation have been proposed as part of a vicious cycle in central nervous system neurodegeneration. Our aim was to study the anti-inflammatory effect of pioglitazone, a peroxisome proliferative activated receptor-γ agonist, on iron-induced oxidative injury in rat brain. METHODS: Intranigral infusion of ferrous citrate (iron) was performed on anaesthetized rats. Pioglitazone (20 mg/kg) was orally administered. Oxidative injury was investigated by measuring lipid peroxidation in the substantia nigra (SN) and dopamine content in the striatum. Western blot assay and DNA fragmentation were employed to study the involvement of α-synuclein aggregation, neuroinflammation as well as activation of endoplasmic reticulum (ER) and mitochondrial pathways in iron-induced apoptosis. RESULTS: Intranigral infusion of iron time-dependently increased α-synuclein aggregation and haem oxygenase-1 levels. Furthermore, apoptosis was demonstrated by TUNEL-positive cells and DNA fragmentation in the iron-infused SN. Systemic pioglitazone was found to potentiate iron-induced elevation in nuclear peroxisome proliferative activated receptor-γ levels. However, pioglitazone inhibited iron-induced α-synuclein aggregation, elevations in interleukin-1ß and interleukin-6 mRNA levels as well as increases in oxygenase-1, cyclo-oxygenase II, nitric oxide synthase and ED-1 protein levels, an indicator of activated microglia. Moreover, iron-induced DNA laddering as well as activation of ER and mitochondrial pathways were attenuated by pioglitazone. In addition, pioglitazone decreased iron-induced elevation in lipid peroxidation in the infused SN and depletion in striatal dopamine level. CONCLUSIONS: Our results suggest that pioglitazone prevents iron-induced apoptosis via both ER and mitochondrial pathways. Furthermore, inhibition of α-synuclein aggregation and neuroinflammation may contribute to the pioglitazone-induced neuroprotection in central nervous system.

Role of autophagy in protection afforded by hypoxic preconditioning against MPP+-induced neurotoxicity in SH-SY5Y cells.

A sublethal preconditioning has been proposed as a neuroprotective strategy against several CNS neurodegenerative diseases. In this study, the involvement of autophagy in the protection provided by hypoxic preconditioning against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity was studied in SH-SY5Y neuroblastoma cells. In contrast to the cytotoxicity of 0.1% oxygen, 1% oxygen hypoxia for 24h did not cause significant cell death. A transient increase in LC3-II level, a biomarker of autophagy, was demonstrated during hypoxic treatment. At the same time, 8-h hypoxia increased fluorescence due to monodansylcadaverine, a specific dye for autophagosomes, in the treated cells. Co-incubation with bafilomycin A1 (10 nM) further increased hypoxia-induced LC3-II levels but 3-methyladenine (3-MA; 10 mM) reduced the elevation in LC3-II levels induced by 8-h hypoxia. Moreover, 8-h hypoxia increased free radical formation and nuclear HIF-1alpha level. Glutathione was found to diminish hypoxia-induced LC3-II elevation. In contrast to the elevated LC3-II level, 8-h hypoxia significantly decreased mitochondrial mass. Furthermore, a rebound elevation in mitochondrial mass was observed under 8-h hypoxia and subsequent 12-h normoxia. Prior hypoxia attenuated the MPP(+)-induced elevation in LC3-II levels and cell death. Moreover, hypoxic pretreatment inhibited MPP(+)-induced activation of caspase-3 and DNA fragmentation. Co-incubation with 3-MA during hypoxia prevented the protection afforded by hypoxic preconditioning against MPP(+)-induced increases in LC3-II levels and neurotoxicity. Taken together, our results suggest that sublethal hypoxia induces autophagy that is mediated by oxidative stress. Furthermore, autophagy may be involved in the protection provided by hypoxic preconditioning against MPP(+)-induced neurotoxicity, indicating a neuroprotective role of autophagy in hypoxic preconditioning.

Spatial regulation of human mesenchymal stem cell differentiation in engineered osteochondral constructs: effects of pre-differentiation, soluble factors and medium perfusion.

OBJECTIVE: The objective of the study was to investigate the combined effects of three sets of regulatory factors: cell pre-differentiation, soluble factors and medium perfusion on spatial control of human mesenchymal stem cell (hMSC) differentiation into cells forming the cartilaginous and bone regions in engineered osteochondral constructs. DESIGN: Bone-marrow derived hMSCs were expanded in their undifferentiated state (UD) or pre-differentiated (PD) in monolayer culture, seeded into biphasic constructs by interfacing agarose gels and bone scaffolds and cultured for 5 weeks either statically (S) or in a bioreactor (BR) with perfusion of medium through the bone region. Each culture system was operated with medium containing either chondrogenic supplements (C) or a cocktail (Ck) of chondrogenic and osteogenic supplements. RESULTS: The formation of engineered cartilage in the gel region was most enhanced by using undifferentiated cells and chondrogenic medium, whereas the cartilaginous properties were negatively affected by using pre-differentiated cells or the combination of perfusion and cocktail medium. The formation of engineered bone in the porous scaffold region was most enhanced by using pre-differentiated cells, perfusion and cocktail medium. Perfusion also enhanced the integration of bone and cartilage regions. CONCLUSIONS: (1) Pre-differentiation of hMSCs before seeding on scaffold was beneficial for bone but not for cartilage formation. (2) The combination of medium perfusion and cocktail medium inhibited chondrogenesis of hMSCs. (3) Perfusion improved the cell and matrix distribution in the bone region and augmented the integration at the bone-cartilage interface. (4) Osteochondral grafts can be engineered by differentially regulating the culture conditions in the two regions of the scaffold seeded with hMSCs (hydrogel for cartilage, perfused porous scaffold for bone).

Evaluation of a microfluidic based cell culture platform with primary human hepatocytes for the prediction of hepatic clearance in human.

Integral to the discovery of new pharmaceutical entities is the ability to predict in vivo pharmacokinetic parameters from early stage in vitro data generated prior to the onset of clinical testing. Within the pharmaceutical industry, a whole host of assay methods and mathematical models exist to predict the in vivo pharmacokinetic parameters of drug candidates. One of the most important pharmacokinetic properties of new drug candidates predicted from these methods and models is the hepatic clearance. Current methods, while useful, are still limited in their predictive efficacy. In order to address this issue, we have established a novel microfluidic in vitro culture system, the patented HmuREL device. The device comprises multiple compartments that are designed to be proportional to the physiological architectures and enhanced with the consideration of flow. Here we demonstrate the functionality of the liver-relevant chamber in the HmuREL device, and the feasibility of utilizing our system for predicting hepatic clearance. Cryopreserved human hepatocytes from a single donor were seeded within the HmuREL device to predict the in vivo hepatic clearance (CL(H)) of six marketed model compounds (carbamazepine, caffeine, timolol, sildenafil, imipramine, and buspirone). The intrinsic clearance rates from static culture controls, as well as clearance rates from the HmuREL device were subsequently compared to in vivo data available from the literature.

Ultrasonic irradiation as a tool to modify the H-desorption from hydrides: MgH(2) suspended in decane.

Effects of ultrasonic irradiation on magnesium hydride (MgH(2)) suspended in decane were investigated with the purpose of improving its hydrogen desorption process. Firstly, we have found that the presence of MgH(2) improves the sonolysis of decane enhancing the amount of hydrogen evolved during the sonication process. The sonicated-MgH(2) maintains its microstructural properties practically unaltered but a drastic reduction of the particle size of MgH(2) (down to approximately 20mum) as well as a high pressure MgH(2) phase are observed. However, no substantial modifications of H-kinetic properties of hydride occur as is determined by thermal desorption measurements. This could be attributed to decomposition of decane during sonication which leads to the formation of carbon compounds that hinder the thermal decomposition of MgH(2).

Melatonin inhibits arsenite-induced peripheral neurotoxicity.

In this study, the effect of melatonin on sodium arsenite (arsenite)-induced peripheral neurotoxicity was investigated using dorsal root ganglion (DRG) explants. After 24-hr incubation, arsenite (30 microm) consistently elevated the expression of heat shock protein 70 and haeme oxygenase-1, two well-known stress proteins, in the treated DRG explants. Co-incubation with melatonin (4 and 20 mm) concentration-dependently attenuated arsenite-induced elevation in stress proteins. Furthermore, melatonin inhibited arsenite-induced phosphorylation of p38 and DNA fragmentation. Inhibition by melatonin of arsenite-induced apoptosis was mediated via inactivating both endoplasmic reticulum (ER) and mitochondrial pathways. In the ER pathway, melatonin suppressed arsenite-induced elevation in activating transcription factor-6 and CCAAT/enhancer-binding protein homologous protein in the nuclear fraction of the treated DRG explants. Moreover, melatonin attenuated arsenite-induced activation of caspase 12, an ER-specific enzyme. In the mitochondrial pathway, arsenite-induced increases in Bcl-2 levels and cytosolic cytochrome c were reduced by melatonin. At the same time, melatonin inhibited arsenite-induced activation of caspase 3 in the treated DRG explants. Compared with glutathione and N-acetyl cysteine, melatonin was more potent than either in inhibiting arsenite-induced elevation in stress proteins. Taken together, our study demonstrates that melatonin is protective against arsenite-induced neurotoxicity in DRG explants. In addition, melatonin prevented arsenite-induced apoptosis via suppression of ER and mitochondrial activation. Our data suggest that melatonin is potentially a therapy for arsenite-induced peripheral neuropathy.

Design and application of microfluidic systems for in vitro pharmacokinetic evaluation of drug candidates.

One of the fundamental challenges facing the development of new chemical entities within the pharmaceutical industry is the extrapolation of key in vivo parameters from in vitro cell culture assays and animal studies. Development of microscale devices and screening assays incorporating primary human cells can potentially provide better, faster and more efficient prediction of in vivo toxicity and clinical drug performance. With this goal in mind, large strides have been made in the area of microfluidics to provide in vitro surrogates that are designed to mimic the physiological architecture and dynamics. More recent advancements have been made in the development of in vitro analogues to physiologically-based pharmacokinetic (PBPK) models - a mathematical model that represents the body as interconnected compartments specific for a particular organ. In this review we highlight recent advancements in human hepatocyte microscale culture, and describe the next generation of integrated devices, whose potential allows for the high throughput assessment of drug metabolism, distribution and pharmacokinetics.

The possible role of arterial radial vibration in heart rate and blood pressure matching.

MOTIVATION: This study tests if the 'oscillating spring' analogy for the radial vibration of the arterial wall can help to describe the relationship between the heart rate (HR), the blood pressure (BP), and properties of the arterial wall when different types of stimulation are applied on the cardiovascular system. It may help to suggest a possible role for arterial radial vibration in the association between the arterial stiffening and hypertension. METHODS: Either mechanical stimulation was applied (0.5-mmHg pressure variation) to Wistar rats by at near-HR frequency (group A) or administered Propranolol (2mg/kg i.p.; group B), and measured HR and BP simultaneously. RESULTS: In both groups, HR and BP were noted to change in the same direction (r2 = 0.72 and 0.62, respectively; p both < 0.05 by F-test). ANCOVA was performed on these two regression lines, and it was found that there was no significant difference between them (p > 0.3). CONCLUSION: In both groups, changes in haemodynamic parameters can be explained by the 'oscillating spring' analogy for the radial vibration of the arterial wall. This illustrates that, when facing various stimulations, it may be an important regulatory mechanism for the heart and the arteries to restore their frequency-matching condition in order to improve the arterial transmission efficiency. Paying more attention to the radial movement of the wall may therefore help to suggest a novel explanation of the mechanism that underlies the bidirectional relation between hypertension and arterial stiffening.

Effects of initial seeding density and fluid perfusion rate on formation of tissue-engineered bone.

We describe a novel bioreactor system for tissue engineering of bone that enables cultivation of up to six tissue constructs simultaneously, with direct perfusion and imaging capability. The bioreactor was used to investigate the relative effects of initial seeding density and medium perfusion rate on the growth and osteogenic differentiation patterns of bone marrow-derived human mesenchymal stem cells (hMSCs) cultured on three-dimensional scaffolds. Fully decellularized bovine trabecular bone was used as a scaffold because it provided suitable "biomimetic" topography, biochemical composition, and mechanical properties for osteogenic differentiation of hMSCs. Trabecular bone plugs were completely denuded of cellular material using a serial treatment with hypotonic buffers and detergents, seeded with hMSCs, and cultured for 5 weeks. Increasing seeding density from 30 x 10(6) cells/mL to 60 x 10(6) cells/mL did not measurably influence the characteristics of tissue-engineered bone, in contrast to an increase in the perfusion rate from 100 microms(-1) to 400 microms(-1), which radically improved final cell numbers, cell distributions throughout the constructs, and the amounts of bone proteins and minerals. Taken together, these findings suggest that the rate of medium perfusion during cultivation has a significant effect on the characteristics of engineered bone.

Metabolism and pharmacokinetics of genipin and geniposide in rats.

Geniposide, an iridoid glucoside, is a major constituent in the fruits of Gardenia jasminoides (Gardenia fruits), a popular Chinese herb. Genipin, the aglycone of geniposide, is used to prepare blue colorants in food industry and also a crosslinking reagent for biological tissue fixation. In this study, we investigated the metabolism and pharmacokinetics of genipin and geniposide in rats. Blood samples were withdrawn via cardiopuncture and the plasma samples were assayed by HPLC method before and after hydrolysis with sulfatase and beta-glucuronidase. The results indicated that after oral administration of genipin or Gardenia fruit decoction, genipin sulfate was a major metabolite in the bloodstream, whereas the parent forms of genipin and geniposide were not detected. Importantly, oral administration of 200mg/kg of genipin resulted in a mortality of 78% (7/9) in rats.