Intra-individual comparison of different gadolinium-based contrast agents in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging

This experiment aimed to compare the ionic(Gadodiamide,Gd-DTPA-BMA) and non-ionic(Gadopentetate dimeglumine,Gd-DTPA) gadolinium-based contrast agents(GBCA) in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI).A C6 glioma model was established in 12 Wistar rats,and magnetic resonance(MR)scans were performed six days after tumor implantation.Imaging was performed using a 3.0-T MR scanner with a 7-inch handmade circular coil.Pre-contrast T1 mapping and dynamic contrast-enhanced T1 WI after a bolus injection(0.2 mL s~(-1)) of GBCA at 0.4 mmol kg~(-1) were performed.Each rat received two DCE-MRI scans,24 h apart.The first and second scans were performed using Gd-DTPA-BMA and Gd-DTPA,respectively.Image data were processed using the Patlak model.Both K~(trans)and V_p maps were generated.Tumors were manually segmented on all 3D K~(trans) and V_p maps.Pixel counts and mean values were recorded for use in a paired f-test Three radiologists independently performed the tumor segmentation and value calculation.The agreements from different observers were subjective to the intra-class correlation coefficient(ICC).Readers demonstrated that the pixel counts of tumors in K~(trans) maps were higher with Gd-DTPA-BMA than with Gd-DTPA(P0.001,all readers).Although the K~(trans) values were higher with Gd-DTPA-BMA than with Gd-DTPA,there was no statistical significance(P0.05,all readers).The pixel counts of tumors in V_p maps,as well as V_p values,showed no obvious difference between the two agents(P0.05,all readers).Excellent interobserver measurement reproducibility and reliability were demonstrated in the ICC tests.The Gd-DTPA-BMA contrast agent had significantly higher pixel counts of glioma in the K~(trans) maps,and an increased tendency for average K~(trans) values,indicating that DCE-MRI with Gd-DTPA-BMA may be more suitable and sensitive for the evaluation of glioma.     

Molecular Magnetic Resonance Imaging of Tumors with a PTPµ Targeted Contrast Agent

Molecular magnetic resonance imaging (MRI) of tumors improves the specificity of MRI by using targeted probes conjugated to contrast-generating metals. The limitation of this approach is in the identification of a target molecule present in sufficient concentration for visualization and the development of a labeling reagent that can penetrate tumor tissue with the fast kinetics required for use in a clinical setting. The receptor protein tyrosine phosphatase PTPµ is a transmembrane protein that is continuously proteolyzed in the tumor microenvironment to generate a high concentration of extracellular fragment that can be recognized by the SBK2 probe. We conjugated the SBK2 peptide to a gadolinium chelate [SBK2-Tris-(Gd-DOTA)₃] to test whether the SBK2 probe could be developed as an MR molecular imaging probe. When intravenously injected into mice bearing flank tumors of human glioma cells, SBK2-Tris-(Gd-DOTA)₃ labeled the tumors within 5 minutes with a high level of contrast for up to 2 hours post-injection. The contrast enhancement of SBK2-Tris-(Gd-DOTA)₃ was significantly higher than that observed with a current MRI macrocyclic gadolinium chelate (Gadoteridol, ProHance) alone or a scrambled control. These results demonstrate that SBK2-Tris-(Gd-DOTA)₃ labeling of the PTPµ extracellular fragment is a more specific MR molecular imaging probe than ProHance or a scrambled control. Consequently, the SBK2 probe may be more useful than the current gold standard reagent for MRI to identify tumors and to co-register tumor borders during surgical resection.     

Calcium-independent inhibition of glucose transport in PC-12 and L6 cells by calcium channel antagonists

The goal of these studies was todetermine whether different calcium channel antagonists affect glucosetransport in a neuronal cell line. Rat pheochromocytoma (PC-12) cellswere treated with L-, T-, and N-type calcium channel antagonists beforemeasurement of accumulation of 2-[³H]deoxyglucose(2-[³H]DG). The L-type channel antagonistsnimodipine, nifedipine, verapamil, and diltiazem all inhibited glucosetransport in a dose-dependent manner (2-150 µM) withnimodipine being the most potent and diltiazem only moderatelyinhibiting transport. T- and N-type channel antagonists had no effecton transport. The L-type channel agonist l-BAY K 8644 alsoinhibited uptake of 2-[³H]DG. The ability of these drugsto inhibit glucose transport was significantly diminished by thepresence of unlabeled 2-DG in the uptake medium. Some experiments wereperformed in the presence of EDTA (4 mM) or in uptake buffer withoutcalcium. The absence of calcium in the uptake medium had no effect oninhibition of glucose transport by nimodipine or verapamil. To examinethe effects of these drugs on a cell model of a peripheral tissue, westudied rat L6 muscle cells. The drugs inhibited glucose transport in L6 myoblasts in a dose-dependent manner that was independent of calciumin the uptake medium. These studies suggest that the calcium channelantagonists inhibit glucose transport in cells through mechanisms otherthan the antagonism of calcium channels, perhaps by acting directly onglucose transporters.

     

Effects of the calcium-sensing receptor A986S polymorphism on serum calcium and parathyroid hormone levels in healthy individuals: a meta-analysis

The calcium-sensing receptor (CaSR) is involved in maintaining calcium homeostasis via the regulation of parathyroid hormone (PTH) secretion. The associations between serum calcium concentrations, parathyroid hormone (PTH) level and CaSR polymorphism A986S have been studied, but results are inconsistent. Therefore, we performed a meta-analysis to clarify the role of this polymorphism on this topic. Weighted mean difference (WMD) and 95% confidence interval (CI) were calculated with random-effects model or fixed-effects model based on the heterogeneity analysis. Overall 2820, 1135 and 3149 healthy individuals were included for total calcium concentration, ionized calcium concentration and PTH level meta-analyses, respectively. Most of the individuals in this meta-analysis were healthy women. Healthy individuals with the AS + SS genotype had significantly higher total and ionized calcium concentrations than those with the AA genotype. However, there was no statistical significance concerning serum PTH level. The pooled WMD for total calcium concentration was 0.028 (95% CI: 0.012-0.045, P = 0.001); for ionized calcium concentration was 0.016 (95% CI: 0.013-0.020, P < 0.0001); and for PTH level was − 0.027 (95% CI: −0.360-0.306, P = 0.874). In conclusion, our meta-analysis indicates that the CaSR A986S polymorphism might be associated with total and ionized calcium concentrations in healthy individuals.     

Effects of the calcium antagonist, diltiazem on in vitro and in vivo/in vitro bone resorption

The effect of the calcium antagonist diltiazem on bone resorption in organ culture has been investigated. It was found that diltiazem was ineffective alone but that in concentrations above 5 mumol/l it reduced mineral and organic resorption induced in vitro by 1.25 dihydroxycholecalciferol (1.25 (OH)2D3). No additivity with calcitonin effects was observed. Diltiazem did not significantly affect bone resorbing activity stimulated by 24,25(OH)2D3. Bone resorption was measured by an in vivo/in vitro technique using 45Ca prelabelled mice. Compared with 1.25(OH)2D3 alone treated group (0.480 pmol/g), it was found that diltiazem (100 nmol/g) reduced bone resorption without effect on calcium and phosphorus plasmatic concentrations at death. These data suggest that such a calcium antagonist is able to inhibit 1.25-(OH)2D3-increased-bone resorption either in vitro or in vivo/in vitro.     

Non-Ionic Contrast Media Induces Oxidative Stress and Apoptosis Through Ca2+ Influx in Human Neutrophils

Non-ionic contrast media (CM) can induce tissue kidney injury via activation of phagocytosis and oxidative stress, although the mechanisms of injury via neutrophils are not clear. We investigated the effects of CM on oxidative stress and Ca²⁺ concentrations in serum and neutrophils of humans. Ten migraine patients were used in the study. Serum and neutrophil samples from patients?? peripheral blood were obtained before (control) and 30?min after non-ionic (iopromide) CM injection. The neutrophils were incubated with non specific transient receptor potential 2 (TRPM2) channel blocker, 2-aminoethoxydiphenyl borate (2-APB), and voltage gated Ca²⁺ channel blockers, verapamil plus diltiazem. Serum and neutrophil lipid peroxidation, apoptosis and intracellular Ca²⁺ concentrations levels were higher in the CM group than in controls. The neutrophilic reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) levels as well as serum vitamin E and ??-carotene concentrations were lower in the CM group than in controls. Neutrophil lipid peroxidation levels were lower in the CM+2-APB and CM+verapamil-diltiazem groups than in the CM group, although GSH, GSH-Px and intracellular Ca²⁺ values increased in the CM+2-APB and CM+verapamil-diltiazem groups. However, caspase-3, caspase-9, vitamin A and vitamin C values were unaltered by CM treatment. In conclusion, we observed that CM induced oxidative stress and Ca²⁺ influx by decreasing vitamin E, ??-carotene and Ca²⁺ release levels in human serum and neutrophils. However, we observed protective effects of Ca²⁺ channel blockers on Ca²⁺ influx in neutrophils.     

Acute intravenous calcitonin: Failure to modify systemic blood pressure

Calcium and a principal calcuim-regulating hormone, PTH, have been characterized as possessing vasoactive properties in the spontaneously hypertensive rat (SHR). Calcitonin is another calcium-regulating peptide with primary, but opposing effects on many of the same target organs, and capable of modifying both extracellular and intracellular calcium distribution. We sought to determine whether calcitonin, like PTH, exhibits vasoactivity in the SHR and its control, the Wistar-Kyoto rat (WKY). Three male SHR and 3 male normotensive WKY received intravenous injections (range 1–100 μg/kg) of synthetic human calcitonin. Seven SHR and 7 WKY received equivalent doses of the more potent peptide, synthetic salmon calcitonin. Intraarterial pressure was monitored continuously. Neither analog of calcitonin produced significant changes in blood pressure. Serum ionized calcium levels 30 minutes postinjection were unchanged from baseline in the WKY; in the SHR, postinjection serum ionized calcium levels were significantly lower than baseline values (pre=1.12±0.01 mmol/l vs. post 1.08±0.01 mmol/l, p<0.05). We conclude that calcitonin modifies extracellular calcium, but does not have demonstrable, acute systemic cardiovascular effects.     

Calcium metabolism and cardiovascular function after spaceflight.

To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.     

Effects of Calcium Ions and of Calcium Channel Blockers on Galvanotaxis of Chlamydomonas reinhardtii

The effects of calcium ions and of the calcium channel blockers verapamil, diltiazem and nifedipine on galvanotaxis in Chlamydomonas have been investigated using a fully automated and computerized population system. Galvanotaxis is a function of the voltage applied to the cell population. However, the galvanotactic orientation also depends on the external calcium concentration. In a calcium-deprived nutrient medium which still contains 6 × 10^?7M calcium, galvanotactic orientation is about 20% of orientation at optimal calcium concentration of 10^?4 M at 9 V. The higher the external calcium concentration is, the lower is the voltage necessary for optimal galvanotactic orientation. The calcium channel blockers diltiazem and nifedipine likewise inhibit galvanotaxis of Chlamydomonas very specifically without impairing motility. Verapamil is effective, but also inhibits motility by causing detachment or shortening of the flagella. Nevertheless, inhibition of galvanotaxis by verapamil is not the only result of decreased motility, because the galvanotactic orientation is impaired to a greater extent than motility. The effectiveness of the three blockers tested in inhibiting galvanotaxis depends on the concentration and on the voltage applied. At 10^?5 M, verapamil causes maximal inhibition of galvanotaxis at 9 V. At increasing concentrations up to 10^?4 M, diltiazem inhibits galvanotaxis more strongly than the other blockers. If the voltage is varied at a constant blocker concentration of 2 × 10^?5 M, nifedipine causes maximal inhibition at 3 V–6 V, diltiazem at 9 V and verapamil above 12 V.     

Manufacturing and <Emphasis Type="Italic">in vivo</Emphasis> inner ear visualization of MRI traceable liposome nanoparticles encapsulating gadolinium

Background  

Treatment of inner ear diseases remains a problem because of limited passage through the blood-inner ear barriers and lack of control with the delivery of treatment agents by intravenous or oral administration. As a minimally-invasive approach, intratympanic delivery of multifunctional nanoparticles (MFNPs) carrying genes or drugs to the inner ear is a future therapy for treating inner ear diseases, including sensorineural hearing loss (SNHL) and Meniere's disease. In an attempt to track the dynamics and distribution of nanoparticles in vivo, here we describe manufacturing MRI traceable liposome nanoparticles by encapsulating gadolinium-tetra-azacyclo-dodecane-tetra-acetic acid (Gd-DOTA) (abbreviated as LPS+Gd-DOTA) and their distribution in the inner ear after either intratympanic or intracochlear administration.     

Bystander response in human lymphoblastoid TK6 cells

The mechanisms of the medium-mediated bystander response induced by γ-rays in non-irradiated TK6 cells were investigated. Cell cultures were irradiated and the culture medium discarded immediately after irradiation and replaced with a fresh one. In cells incubated with conditioned medium from irradiated cells (CM), a significant decrease in cell viability and cloning efficiency was observed, together with a significant increase in apoptosis, also in directly irradiated cells. To examine whether bystander apoptosis involved the extrinsic pathway, an inhibitor of caspase-8 was added to CM cultures, which significantly decreased apoptosis to control levels. The addition to CM of ROS scavengers, Cu–Zn superoxide dismutase and N-acetylcysteine did not affect the induction of apoptosis. To assess whether CM treatment activates a DNA damage response, also the formation of γ-H2AX foci, as markers of double-strand breaks and their colocalisation with 53-binding protein 1 (53BP1) and the protein mutated in the Nijmegen breakage syndrome 1 (NBS1) was analysed. In cultures treated for 2 h with CM, 9–11% of cells showed γ-H2AX foci, which partially or totally lacked colocalisation with 53BP1 and NBS1 foci. About 85% of irradiated cells were positive for γ-H2AX foci, which colocalised with 53BP1 and NBS1 proteins. At 24 h from irradiation, very few irradiated cells retained foci, fitting DNA repair kinetics. The number of foci-positive bystander cells also decreased to background values 24 h after CM incubation. Our results suggest that irradiated TK6 cells release into the medium some soluble factors, not ROS, which are responsible for the cytotoxic effects induced in bystander cells. In our experimental system, the role of ROS appeared to be of minor importance in inducing cell mortality, but probably critical in activating the DNA damage response in the responsive fraction of bystander cells.     

The role of Ca2+ and protein kinase C in the differentiation of HL-60 cells induced by 1 alpha,25(OH)2D3 and diltiazem

The roles of calcium (Ca2+) and protein kinase C in the differentiation of HL-60 cells induced by 1 alpha,25(OH)2D3 (D3) and/or a Ca2+ antagonist, diltiazem(D-cis, L-cis), were elucidated. D3 and diltiazem (100 microM) inhibited cell proliferation, and diltiazem enhanced the D3-induced differentiation. There was no difference in potency between the two isomers of diltiazem in the enhancing activity, in spite of their different pharmacological activity. The concentration of free Ca2+ in the HL-60 cells following D3 and/or diltiazem treatment significantly increased. A protein kinase C inhibitor, H-7, inhibited the phenotypic differentiation induced by D3. These results suggest that Ca2+ and protein kinase C play an important role in the differentiation of HL-60 cells induced by D3 and diltiazem.     

Intracellular calcium buffering capacity in isolated squid axons

Changes in ionized calcium were studied in axons isolated from living squid by measuring absorbance of the Ca binding dye Arsenazo III using multiwavelength differential absorption spectroscopy. Absorption changes measured in situ were calibrated in vitro with media of ionic composition similar to axoplasm containing CaEGTA buffers. Calcium loads of 50-2,500 μmol/kg axoplasm were induced by microinjection, by stimulation in 112 mM Ca seawater, or by soaking in choline saline with 1-10 mM Ca. Over this range of calcium loading of intact axoplasm, the ionized calcium in the axoplasm rose about 0.6 nM/μM load. Similar loading in axons preteated with carbonyl cyanide 4- trifluoromethoxyphenylhydrazone (FCCP) to inhibit the mitochondrial proton gradient increased ionized calcium by 5-7 percent of the imposed load, i.e. 93-95 percent of the calcium load was buffered by a process insensitive to FCCP. This FCCP- insensitive buffer system was not saturated by the largest calcium loads imposed, indicating a capacity of at least several millimolar. Treatment of previously loaded axons with FCCP or apyrase plus cyanide produced rises in ionized calcium which could be correlated with the extent of the load. Analysis of results indicated that, whereas only 6 percent of the endogenous calcium in fresh axons is stored in the FCCP-sensitive (presumably mitochondrial) buffer system, about 30 percent of an imposed exogenous load in the range of 50-2,500 μM is taken up by this system.     

Conformation and structure of polymeric contrast agents for medical imaging

The structure of Gd-DTPA-polylysine, Gd-DOTA-polylysine, Gd-SCN-Bz-DOTA-polylysine, and Gd-DTPA-poly(glu:lys) was investigated with circular dichroism, gel permeation chromatography, low angle light scattering, and proton longitudinal relaxivity. Molecular modeling calculations were performed and predicted helical secondary structure for charged Gd-chelator residues, i.e., Gd-DTPA, when the DTPA conjugation levels reached 90% and higher. This helical secondary structure was observed with circular dichroism. The conformational transition from coiled to extended linear was observed also by gel permeation chromatography and by proton relaxivity measurements. The helical secondary structure was not observed when the chelator was changed to DOTA. The residue charge interactions were eliminated in this case since the Gd-DOTA complex had no net charge. For this construct, the gel permeation and relaxivity measurements indicated a coiled conformation. An extended linear conformation was regained when the chelator complex was changed to Gd-SCN-Bz-DOTA, which had a net negative charge. The functional aspects of these structures were investigated by MR imaging of an animal tumor model. The linear extended polymer constructs gave 10-fold higher tumor signals then the coiled-collapsed constructs, indicating a much higher degree of trans-endothelial transport in the tumors.     

Endothelin: differential effects in vascular and nonvascular smooth muscle

Endothelin, a potent vasoconstrictor, produced concentration-dependent contractions in aorta, trachea and bladder body obtained from rat and rabbit. Contractions developed slowly, reaching maxiMum within 15-20 min. Although, in both rat and rabbit tissues, endothelin was 3- to 10-fold more potent in contracting vascular (approximate EC50, 1 nM) than nonvascular smooth muscle, rat trachea and rabbit bladder did contract in response to endothelin. Rat bladder body and rabbit trachea were the least sensitive tissues with only modest contractile responses to endothelin. To determine the role of calcium in these endothelin-induced contractions, the effects of diltiazem and nitrendipine were examined. Although diltiazem (5 x 10-5) M) or nitrendipine (10(-6) M) markedly attenuated contractions produced by KCl, neither agent significantly affected concentration response curves produced by endothelin in rabbit aorta or rat trachea. In rat aorta, nitrendipine had no effect on endothelin responses, whereas diltiazem modestly decreased the maximal contraction to endothelin. However, in rabbit bladder, both calcium channel blockers significantly decreased the maximum response to endothelin with no change in EC50. These results indicate that smooth muscle sensitivity to the contractile effects of endothelin may be both species and tissue specific.     

Role of vascular adrenergic mechanisms in the haemodynamic and PGI2 stimulating effects of angiotensin in diabetic dogs

In aware of the well-known altered vascular responsiveness in the diabetic vasculature, this study aimed to compare the haemodynamic and PGI₂ releasing effects of angiotensin in metabolically healthy (12) and alloxan-(560 umol/kg) diabetic (12) dogs as well as to analyze the role of vascular adrenoceptors in this. In vivo the effect of intracoronarially administered angiotensin (63-125-250-500-1000 pmol/kg/min) on coronary blood flow, mean arterial blood pressure, myocardial contractile force and heart rate was investigated without and with pretreatment of 2 umol/kg phentolamine. In vitro PGI₂ release by isolated coronary rings was induced by 50 nmol/1 angiotensin before and after pretreatment with 5 umol/1 phentolamine and measured by radioimmunoassay. Angiotensin enhances dose-dependently both the mean arterial blood pressure and coronary blood flow, while it provokes a considerable (p < 0.05) increase of PGI₂ formation by isolated coronary arterial rings. These alterations could be prevented by phentolamine administration both in vivo and in vitro, while this drug did not affect the angiotensin-induced enhancement of diabetic coronary blood flow. On the other hand the increase of blood pressure by angiotensin was found to be more (p < 0.05) expressed in diabetes and it could be further potentiated by phentolamine. PGI₂ synthesis by isolated diabetic coronary rings could not be modified either by angiotensin alone or in combination with phentolamine. On the basis of above data, the lack of stimulated vascular PGI₂ formation mediated by alpha-adrenergic mechanisms is supposed to causatively contribute to the diminished sensitivity of diabetic coronary arteries to vasodilation.     

Lipid Dependent Cardio- Haemodynamic Tolerability of Liposomes in Rats

Abstract

Rationale and Objectives:

The use of contrast-carrying liposomes in diagnostic applications (1) or of haemoglobin liposomes in blood replacement therapy (2) requires infusion of large lipid doses. Saturated lipids like HSPC are often used in these formulations to render the liposomes more stable (3). Previous studies have indicated that intravenous injection of such liposome preparations can result in significant haemodynamic changes in rats (14). The purpose of this study was to systematically evaluate cardio- and haemodynamic effects of liposomes prepared from saturated and unsaturated phosphatidylcholine alone or in combination with other lipid components.

Methods;

Liposomes made from SPC, HSPC, DSPC, DSPC/CH, DSPC/DSPG, DSPC/CH/DSPG were infused in anaesthetized rats (total lipid dose: 300 mg lipid/kg BW) and cardio-heamodynamic parameters were measured.

Results:

DSPC-liposomes significantly reduced blood pressure (BP) and total peripheral resistance (TPR) by -53.7 % and -45.7 % of prevalue, respectively. Similar results were obtained for HSPC-liposomes. Marked ECG-changes were recorded for both formulations. SPC-liposomes caused a transient and moderate reduction of BP and TPR (-17.0 % and -22.3 %, respectively). Short-lasting ECG changes were also observed. The addition of cholesterol or DSPG to DSPC liposomes reduced cardiac and haemodynamic side effects in rats.

Conclusion;

The lipid composition of liposomes is of major importance for the incidence of cardiovascular side effects in rats. Liposomes composed of pure saturated phosphatidylcholine cause significant changes which can be diminished by the addition of other lipid components like cholesterol.     

In vivo effects of fumonisin B1-producing and fumonisin B1-nonproducing Fusarium moniliforme isolates are similar: Fumonisins B2 and B3 cause hepato- and nephrotoxicity in rats

Fumonisins are mycotoxins produced by Fusarium moniliforme, F. proliferatum, and related Fusarium species found on corn. They occur naturally in corn-based feeds and foods and are suspected human esophageal carcinogens. Fumonisin B₁ (FB₁), the most common homologue, causes the animal diseases associated with F. moniliforme. Hepato- and nephrotoxicities, disrupted sphingolipid metabolism, and liver cancer have been found in rats fed FB₁. To determine the in vivo effects of diets containing fumonisins B₂ (FB₂) or B₃ (FB₃), male rats were fed culture materials (CM) of FB₁ non-producing F. moniliforme isolates to provide low (4.6–6.7 ppm), mid (32–49 ppm) or high (219–295 ppm) dietary levels of either FB₂ (FB₂CM) or FB₃ (FB₃CM). Other groups were fed culture material of an FB₁ producing isolate (FB₁CM) providing 6.9, 53 or 303~ppm total fumonisins (FB₁ : FB₂ : FB₃ = 1.0 : 0.38 : 0.15) and a tenth group was fed a control diet having no detectable fumonisins. One-half (n = 5/group) the animals were killed after three weeks, at which time the toxicological and histopathological effects of the three culture materials were similar, mimicked the effects of FB₁, and included decreased body weight gains, serum chemical indicators of hepatotoxicity, decreased kidney weights, and apoptosis of hepatocytes and kidney tubular epithelium. FB₁CM, FB₂CM, and FB₃CM affected sphingolipids, causing increased sphinganine to sphingosine ratios (Sa/So) in both liver and kidneys. The remaining animals (n = 5/group) were fed a control diet for three additional weeks. All body weight and tissue specific effects, including increased Sa/So, induced by the FB₂CM, FB₃CM and low level FB₁CM diets were absent following the recovery period. Except for mild biliary lesions found in the high dose FB₁CM group and a few apoptotic hepatocytes present in one mid- and two high-dose FB₁CM rats, no evidence of toxicity remained in these groups following the recovery period.This revised version was published online in October 2005 with corrections to the Cover Date.     

The Effect of Black Tea on Blood Pressure: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

Objective

Epidemiological evidence has linked consumption of black tea, produced from Camellia sinensis, with a reduced risk of cardiovascular diseases. However, intervention studies on the effects of tea consumption on blood pressure (BP) have reported inconsistent results. Our objective was to conduct a systematic literature review with meta-analysis of controlled human intervention studies examining the effect of tea consumption on BP.

Methods

We systematically searched Medline, Biosis, Chemical Abstracts and EMBASE databases through July 2013. For inclusion, studies had to meet the following pre-defined criteria: 1) placebo controlled design in human adults, 2) minimum of 1 week black tea consumption as the sole intervention, 3) reported effects on systolic BP (SBP) or diastolic BP (DBP) or both. A random effects model was used to calculate the pooled overall effect of black tea on BP.

Results

Eleven studies (12 intervention arms, 378 subjects, dose of 4–5 cups of tea) met our inclusion criteria. The pooled mean effect of regular tea ingestion was −1.8 mmHg (95% CI: −2.8, −0.7; P = 0.0013) for SBP and −1.3 mmHg (95% CI: −1.8, −0.8; P<0.0001) for DBP. In covariate analyses, we found that the method of tea preparation (tea extract powders versus leaf tea), baseline SBP and DBP, and the quality score of the study affected the effect size of the tea intervention (all P<0.05). No evidence of publication bias could be detected.

Conclusions

Our meta-analysis indicates that regular consumption of black tea can reduce BP. Although the effect is small, such effects could be important for cardiovascular health at population level.     

Detection of cadherin-17 in human colon cancer LIM1215 cell secretome and tumour xenograft-derived interstitial fluid and plasma

Colorectal cancer (CRC), one of the most prevalent cancers in the western world, is treatable if detected early. However, 70% of CRC is detected at an advanced stage. This is largely due to the inadequacy of current faecal occult blood screening testing and costs involved in conducting population-based colonoscopy, the ‘gold standard’ for CRC detection. Another biomarker for CRC, carcinoembryonic antigen, while useful for monitoring CRC recurrence, is ineffective, lacking the specificity required early detection of CRC. For these reasons there is a need for more effective blood-based markers for early CRC detection. In this study we targeted glycoproteins secreted from the human colon carcinoma cell line LIM1215 as a source of potential CRC biomarkers. Secreted candidate glycoproteins were confirmed by MS and validated by Western blot analysis of tissue/tumour interstitial fluid (Tif) from LIM1215 xenograft tumours grown in immunocompromised mice. Overall, 39 glycoproteins were identified in LIM1215 culture media (CCM) and 5 glycoproteins in LIM1215 tumour xenograft Tif; of these, cadherin-17 (CDH17), galectin-3 binding protein (LGALS3BP), and tyrosine-protein kinase-like 7 (PTK7) were identified in both CM and glycosylation motifs. Swiss-Prot was used to annotate Tif. Many of the glycoproteins identified in this study (e.g., AREG, DSG2, EFNA1, EFNA3, EFNA4, EPHB4, ST14, and TIMP1) have been reported to be implicated in CRC biology. Interestingly, the cadherin-17 ectodomain, but not full length cadherin-17, was identified in CM, Tif and plasma derived from mice bearing the LIM1215 xenograft tumour. To our knowledge, this is the first report of the cadherin-17 ectodomain in plasma. In this study, we report for the first time that the presence of full-length cadherin-17 in exosomes released into the CM. This article is part of a Special Issue entitled: An Updated Secretome.