A genetic polymorphism of matrix metalloproteinase 9 (MMP-9) affects the changes in circulating MMP-9 levels induced by highly active antiretroviral therapy in HIV patients

We examined whether two functional polymorphisms (g.-1562C>T and g.-90(CA)14-24) in the matrix metalloproteinase (MMP)-9 gene or MMP-9 haplotypes affect the circulating levels of pro-MMP-9 and pro-MMP-9/TIMP-1 (tissue inhibitor of metalloproteinase-1) ratios in AIDS patients, and modulate alterations in these biomarkers after highly active antiretroviral therapy (HAART). We studied 82 patients commencing HAART. Higher pro-MMP-9 concentrations and pro-MMP-9/TIMP-1 ratios were found in CT/TT patients compared with CC patients. HAART decreased pro-MMP-9 levels and pro-MMP-9/TIMP-1 ratios in CT/TT patients, it did not modify pro-MMP-9 levels and it increased pro-MMP-9/TIMP-1 ratios in CC patients. The g.-90(CA)14-24 polymorphism, however, produced no significant effects. Moreover, we found no significant differences in HAART-induced changes in plasma pro-MMP-9, TIMP-1 and pro-MMP-9/TIMP-1 ratios when different MMP-9 haplotypes were compared. These findings suggest that the g.-1562C>T polymorphism affects pro-MMP-9 levels in patients with AIDS and modulates the alterations in pro-MMP-9 levels caused by HAART, thus possibly affecting the risk of cardiovascular complications. The Pharmacogenomics Journal (2009) 9, 265-273; doi: 10.1038/tpj.2009.13; published online 21 April 2009

Assessment of matrix metalloproteinase (MMP)-2, MMP-8, MMP-9, and their inhibitors, the tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2 in obese children and adolescents

Objectives: To compare the circulating levels of matrix metalloproteinase (MMP)-8, pro-MMP-2, pro-MMP-9, and total MMP-9, their endogenous inhibitors, the tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2, and the MMP-8/TIMP-1, MMP-9/TIMP-1, and MMP-2/TIMP-2 ratios in normotensive obese children and adolescents with those found in non obese children and adolescents. Design and methods: We studied 40 obese and 40 non obese (controls) children and adolescents in this cross-sectional study. MMP and TIMP concentrations were measured in plasma samples by gelatin zymography and ELISA. Results: Obese children and adolescents had higher circulating MMP-8 concentrations, lower plasma TIMP-1 concentrations, and higher MMP-8/TIMP-1 ratios than non obese controls (P < 0.05). We found no differences in pro-MMP-9 or total MMP-9 levels, or in MMP-9/TIMP-1 ratios between groups (P > 0.05). While we found no significant differences in pro-MMP-2 levels (P > 0.05) obese Subjects had higher TIMP-2 concentrations and lower pro-MMP-2/TIMP-2 ratios (P < 0.05) than non obese controls. Conclusions: In conclusion, we found evidence indicating higher net MMP-8 (but not MMP-9 and MMP-2) activity in childhood obesity. The increased MMP-8 levels found in obese children suggest a possibly relevant pathophysiological mechanism that may be involved in the increase of cardiovascular risk associated with childhood obesity. (c) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Increased circulating levels of matrix metalloproteinase (MMP)-8, MMP-9, and pro-inflammatory markers in patients with metabolic syndrome

Background: Metabolic syndrome (MetS) predisposes to cardiovascular complications. Increased concentrations of pro-inflammatory mediators and imbalanced concentrations of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) may reflect the pathophysiology of MetS. We compared the circulating levels of MMPs, TIMPs, and inflammatory mediators in MetS patients with those found in healthy controls. Methods: We studied 25 healthy subjects and 25 MetS patients. The plasma levels of pro-MMP-2 and pro-MMP-9 were determined by gelatin zymography. The plasma concentrations of MMP-8, MMP-3, TIMP-1, TIMP-2, monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), intercellular adhesion molecule (sICAM-1), and sP-selectin were measured by ELISA kits. Results: We found higher sP-selectin, sICAM-1, MCP-1, and IL-6 (all P<0.05) concentrations in MetS patients compared with healthy controls. No differences in pro-MMP-2, MMP-3, and TIMP-2 levels were found (all P>0.05). However, we found higher pro-MMP-9, MMP-8. and TIMP-1 levels in MetS patients compared with healthy controls (all P<0.05). Conclusions: Patients with MetS have increased circulating concentrations of pro-MMP-9, MMP-8, and TIMP-1 that are associated with increased concentrations of pro-inflammatory mediators and adhesion molecules. These findings suggest that MMPs may have a role in the increased cardiovascular risk of MetS patients. Pharmacological interventions targeting MMPs, especially MMP-9 and MMP-8 deserve further investigation in MetS patients. (C) 2009 Elsevier B.V. All rights reserved.

Human alveolar bone cell proliferation, expression of osteoblastic phenotype, and matrix mineralization on porous titanium produced by powder metallurgy

Objective: This study aimed at investigating the influence of the porous titanium (Ti) structure on the osteogenic cell behaviour. Materials and methods: Porous Ti discs were fabricated by the powder metallurgy process with the pore size typically between 50 and 400 mm and a porosity of 60%. Osteogenic cells obtained from human alveolar bone were cultured until subconfluence and subcultured on dense Ti (control) and porous Ti for periods of up to 17 days. Results: Cultures grown on porous Ti exhibited increased cell proliferation and total protein content, and lower levels of alkaline phosphatase (ALP) activity than on dense Ti. In general, gene expression of osteoblastic markers-runt-related transcription factor 2, collagen type I, alkaline phosphatase, bone morphogenetic protein-7, and osteocalcin was lower at day 7 and higher at day 17 in cultures grown on porous Ti compared with dense Ti, a finding consistent with the enhanced growth rate for such cultures. The amount of mineralized matrix was greater on porous Ti compared with the dense one. Conclusion: These results indicate that the porous Ti is an appropriate substrate for osteogenic cell adhesion, proliferation, and production of a mineralized matrix. Because of the three-dimensional environment it provides, porous Ti should be considered an advantageous substrate for promoting desirable implant surface-bone interactions.

Lercanidipine decreases vascular matrix metalloproteinase-2 activity and protects against vascular dysfunction in diabetic rats

Abnormal matrix metalloproteinases (MMPs) activity causes cardiovascular diseases. Because hyperglycemia increase MMPs activities through increased oxidative stress. we hypothesized that antioxidant effects produced by lercanidipine could attenuate the increases in MMP-2 expression/activity in diabetic rats. Control and diabetic (alloxan-induced diabetes) rats received lercanidipine 2.5 mg/kg/day (or tap water) starting three weeks after alloxan (or vehicle) injections. Blood pressure was monitored weekly. After six weeks of treatment, vascular reactivity and structural changes were assessed in aortic rings. MMP-2 levels were determined by gelatin zymography, and MMP-2/tissue inhibitor of metalloproteinases (TIMP)-2 mRNA levels were determined by quantitative real time RT-PCR. Plasma thiobarbituric acid reactive substances concentrations were determined by fluorimetry. Lercanidipine produced antihypertensive effects (201 +/- 5 vs. 163 +/- 7 mm Hg in diabetic rats untreated and treated with lercaniclipine, respectively; P < 0.01) and reversed the impairment in endothelium-dependent vasorelaxation in diabetic rats. Increased MMP-2 and Pro-MMP-2 levels were found in the aortas of diabetic rats (both P < 0.001). Lercandipine attenuated the increases in oxidative stress and in MMP-2 (both P < 0.05). While diabetes induced no major structural changes, it caused a 16-fold increase in the ratio of MMP-2/TIMP-2 mRNA expression, which was completely reversed by lercanidipine (both P < 0.001). These results show that antioxidant and beneficial vascular effects produced by lercanidipine in diabetic rats are associated with reversion of the imbalance in vascular MMP-2MMP-2 expression. (C) 2008 Published by Elsevier B.V.

High concentration of residual aluminum oxide on titanium surface inhibits extracellular matrix mineralization

In the present study we characterized titanium (Ti) surfaces submitted to different treatments and evaluated the response of osteoblasts derived from human alveolar bone to these surfaces. Five different surfaces were evaluated: ground (G), ground and chemical etched (G1-HF for 60 s), sand blasted (SB-Al2O3 particles 65 pm), sand blasted and chemical etched (SLA1-HF for 60 s and SLA2-HF for 13 s). Surface morphology was evaluated under SEM and roughness parameters by contact scanning instrument. The presence of Al2O3 was detected by EDS and the amount calculated by digital analyses. Osteoblasts, were cultured on these surfaces and it was evaluated: cell adhesion, proliferation, and viability, alkaline phosphatase activity, total protein content, and matrix mineralization formation. Physical and chemical treatments produced very different surface morphologies. Al2O3 residues were detected on SB and SLA2 surfaces. Only matrix mineralization formation was affected by different surface treatments, being increased on rough surface (SLA1) and reduced on surface with high amount of Al2O3 residues (SB). On the basis of these findings, it is possible to conclude that high concentration of residual Al2O3 negatively interfere with the process of matrix mineralization formation in contact with Ti implant surfaces. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 87A: 588-597, 2008

Inverse relationship between markers of nitric oxide formation and plasma matrix metalloproteinase-9 levels in healthy volunteers

Background: Nitric oxide (NO) is a major regulator of cardiovascular homeostasis and has anti-atherogenic properties. Reduced NO formation is associated with endothelial dysfunction and with cardiovascular risk factors. Although NO downregulates the expression and activity of the pro-atherogenic enzyme matrix metalloproteinase-9 (MMP-9), no previous clinical study has examined whether endogenous NO formation is inversely associated with the circulating levels of pro-MMP-9, which are associated with cardiovascular events. We examined this hypothesis in 175 healthy male subjects who were non-smokers. Methods: To assess NO bioavailability, the plasma concentrations of nitrite, nitrate, and cGMP were determined using an ozone-based chemiluminescence assay and an enzyme immunoassay. Pro-MMP-9 and pro-MMP-2 levels were measured in plasma samples by gelatin zymography. Results: We found significant negative correlations between pro-MMP-9 levels and plasma nitrite (P=0.035, rs=-0.159), nitrate (P=0.040, rs=-0.158), and cGMP (P=0.011, rs=-0.189) concentrations. However, no significant correlations were found between pro-MMP-2 levels and the plasma concentrations of markers of NO bioavailability (all P>0.05). Conclusions: There is an inverse relationship between markers of NO formation and plasma MMP-9 levels. This finding may shed some light on the possible mechanisms involved in the increased cardiovascular risk of apparently healthy subjects with low NO bioavailability or high circulating levels of pro-MMP-9. (C) 2008 Elsevier B.V. All rights reserved.

Effects of statins on matrix metalloproteinases and their endogenous inhibitors in human endothelial cells

Statins exert anti-inflammatory effects and downregulate matrix metalloproteinases (MMPs) expression, thus contributing to restore cardiovascular homeostasis in cardiovascular diseases. We aimed at comparing the effects of different statins (simvastatin, atorvastatin, and pravastatin) on MMP-2, MMP-9, tissue inhibitors of metalloproteinases (TIMP)-1, TIMP-2, and MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios released by human umbilical vein endothelial cells (HUVEC) stimulated by phorbol myristate acetate (PMA). HUVECs were incubated with statins (0.1-10 mu M) for 12 h before stimulation with PMA 100 nM. Monolayers were used to perform cell viability assays and the supernatants were collected to determine MMPs and TIMPs levels by gelatin zymography and/or enzyme immunoassay. While treatment with PMA increased MMP-9 and TIMP-1 levels (by 556% and 159%, respectively; both P < 0.05), it exerted no effects on MMP-2 and TIMP-2 levels. Simvastatin and atorvastatin, but not pravastatin, attenuated PMA-induced increases in MMP-9 levels (P < 0.05). Only atorvastatin decreased baseline MMP-2 levels significantly (P < 0.05). We found no effects on TIMP-2 levels. Simvastatin and atorvastatin, but not pravastatin, decreased MMP-9/TIMP-1 ratio significantly (both P < 0.05), whereas atorvastatin and pravastatin, but not simvastatin, decreased MMP-2/TIMP-2 ratio significantly (both P < 0.05). Our data support the notion that statins with different physicochemical features exert variable effects on MMP/TIMP ratios (which reflect net MMP activity). Our results suggest that more lipophilic statins (simvastatin and atorvastatin), but not the hydrophilic statin pravastatin, downregulate net MMP-9 activity. However, atorvastatin and pravastatin may downregulate net MMP-2 activity. The clinical implications of the present findings deserve further investigation.

Matrix-product codes over Fq

Codes C-1,...,C-M of length it over F-q and an M x N matrix A over F-q define a matrix-product code C = [C-1 (...) C-M] (.) A consisting of all matrix products [c(1) (...) c(M)] (.) A. This generalizes the (u/u + v)-, (u + v + w/2u + v/u)-, (a + x/b + x/a + b + x)-, (u + v/u - v)- etc. constructions. We study matrix-product codes using Linear Algebra. This provides a basis for a unified analysis of /C/, d(C), the minimum Hamming distance of C, and C-perpendicular to. It also reveals an interesting connection with MDS codes. We determine /C/ when A is non-singular. To underbound d(C), we need A to be 'non-singular by columns (NSC)'. We investigate NSC matrices. We show that Generalized Reed-Muller codes are iterative NSC matrix-product codes, generalizing the construction of Reed-Muller codes, as are the ternary 'Main Sequence codes'. We obtain a simpler proof of the minimum Hamming distance of such families of codes. If A is square and NSC, C-perpendicular to can be described using C-1(perpendicular to),...,C-M(perpendicular to) and a transformation of A. This yields d(C-perpendicular to). Finally we show that an NSC matrix-product code is a generalized concatenated code.

The validity of self-reported energy intake as determined using the doubly labelled water technique

In the 1980s the development of the doubly labelled water (DLW) technique made it possible to determine the validity of dietary assessment methods using external, independent markers of intake in free-living populations. Since then, the accuracy of self-reported energy intake (EI) has been questioned on a number of occasions as under-reporting has been found to be prevalent in many different populations. This paper is a review of investigations using the DLW technique in conjunction with self-reported EI measures in groups including adults, children and adolescents, obese persons, athletes, military personnel and trekking explorers. In studies where a person other than the subject is responsible for recording dietary intake, such as parents of young children, EI generally corresponds to DLW determined energy expenditure. However, in instances where the subjects themselves report their intake, EI is generally under-reported when compared with energy expenditure. It was originally believed that this phenomenon of under-reporting was linked to increased adiposity and body size, however, it is now apparent that other factors, such as dietary restraint and socio-economic status, are also involved. This paper therefore aims to present a more comprehensive picture of under-reporting by tying in the findings of many DLW studies with other studies focusing particularly on the characteristics and mechanisms for under-reporting. Awareness of these characteristics and mechanisms will enable researchers to obtain more accurate self-reports of EI using all dietary recording techniques.

A technique for preserving pigmentation in some capsalid monogeneans for taxonomic purposes

A technique is described to preserve the pigment found in the bodies and the intestine of some brightly coloured and darkly pigmented benedeniine capsalid monogeneans. Previous studies of these pigmented capsalids have proven difficult because the pigmentation usually disappears when the worms are fixed using preservatives containing concentrations of formalin over 5% and/or ethanol, acetic acid, chromic acid, picric acid and mercuric chloride. The technique developed here uses a fixative comprising glycerol, acetone and formalin (GAF). After fixation under light coverslip compression for three minutes, specimens are transferred to absolute acetone for three minutes and cleared in a mixture of nine parts cedar wood oil and one part absolute acetone before mounting in Canada balsam. Processing must be carried out quickly, as these chemicals will cause the pigments to fade if the specimens are exposed to them for too long. Pigmented benedeniines processed using this technique retain the distribution, intensity and colour observed in live worms. The colour and distribution of pigmentation in monogeneans may be of taxonomic importance and this technique aids preparation of whole-mounts suitable for registration as type-material.

Population pharmacokinetics of perhexiline from very sparse, routine monitoring data

Using NONMEM, the population pharmacokinetics of perhexiline were studied in 88 patients (34 F, 54 M) who were being treated for refractory angina. Their mean +/- SD (range) age was 75 +/- 9.9 years (46-92), and the length of perhexiline treatment was 56 +/- 77 weeks (0.3-416). The sampling time after a dose was 14.1 +/- 21.4 hours (0.5-200), and the perhexiline plasma concentrations were 0.39 +/- 0.32 mg/L (0.03-1.56). A one-compartment model with first-order absorption was fitted to the data using the first-order (FO) approximation. The best model contained 2 subpopulations (obtained via the $MIXTURE subroutine) of 77 subjects (subgroup A) and 11 subjects (subgroup B) that had typical values for clearance (CL/F) of 21.8 L/h and 2.06 L/h, respectively. The volumes of distribution (V/F) were 1470 L and 260 L, respectively, which suggested a reduction in presystemic metabolism in subgroup B. The interindividual variability (CV%) was modeled logarithmically and for CL/F ranged from 69.1% (subgroup A) to 86.3% (subgroup B). The interindividual variability in V/F was 111%. The residual variability unexplained by the population model was 28.2%. These results confirm and extend the existing pharmacokinetic data on perhexiline, especially the bimodal distribution of CL/F manifested via an inherited deficiency in hepatic and extrahepatic CYP2D6 activity.

Automated edge-detection technique for measurement of brachial artery reactivity: A comparison of concordance with manual measurements

Concerns have been raised about the reproducibility of brachial artery reactivity (BAR), because subjective decisions regarding the location of interfaces may influence the measurement of very small changes in lumen diameter. We studied 120 consecutive patients with BAR to address if an automated technique could be applied, and if experience influenced reproducibility between two observers, one experienced and one inexperienced. Digital cineloops were measured automatically, using software that measures the leading edge of the endothelium and tracks this in sequential frames and also manually, where a set of three point-to-point measurements were averaged. There was a high correlation between automated and manual techniques for both observers, although less variability was present with expert readers. The limits of agreement overall for interobserver concordance were 0.13 +/-0.65 mm for the manual and 0.03 +/-0.74 mm for the automated measurement. For intraobserver concordance, the limits of agreement were -0.07 +/-0.38 mm for observer 1 and -0.16 +/-0.55 mm for observer 2. We concluded that BAR measurements were highly concordant between observers, although more concordant using the automated method, and that experience does affect concordance. Care must be taken to ensure that the same segments are measured between observers and serially.

Derivation of the probability distribution function for the local density of states of a disordered quantum wire via the replica trick and supersymmetry

We consider the statistical properties of the local density of states of a one-dimensional Dirac equation in the presence of various types of disorder with Gaussian white-noise distribution. It is shown how either the replica trick or supersymmetry can be used to calculate exactly all the moments of the local density of states.' Careful attention is paid to how the results change if the local density of states is averaged over atomic length scales. For both the replica trick and supersymmetry the problem is reduced to finding the ground state of a zero-dimensional Hamiltonian which is written solely in terms of a pair of coupled spins which are elements of u(1, 1). This ground state is explicitly found for the particular case of the Dirac equation corresponding to an infinite metallic quantum wire with a single conduction channel. The calculated moments of the local density of states agree with those found previously by Al'tshuler and Prigodin [Sov. Phys. JETP 68 (1989) 198] using a technique based on recursion relations for Feynman diagrams. (C) 2001 Elsevier Science B.V. All rights reserved.

Development and implementation of the population Fisher information matrix for the evaluation of population pharmacokinetic designs.

In population pharmacokinetic studies, the precision of parameter estimates is dependent on the population design. Methods based on the Fisher information matrix have been developed and extended to population studies to evaluate and optimize designs. In this paper we propose simple programming tools to evaluate population pharmacokinetic designs. This involved the development of an expression for the Fisher information matrix for nonlinear mixed-effects models, including estimation of the variance of the residual error. We implemented this expression as a generic function for two software applications: S-PLUS and MATLAB. The evaluation of population designs based on two pharmacokinetic examples from the literature is shown to illustrate the efficiency and the simplicity of this theoretic approach. Although no optimization method of the design is provided, these functions can be used to select and compare population designs among a large set of possible designs, avoiding a lot of simulations.