In vitro ovine articular chondrocyte proliferation: experiments and modelling

This study focuses on analysis of in vitro cultures of chondrocytes from ovine articular cartilage. Isolated cells were seeded in Petri dishes, then expanded to confluence and phenotypically characterized by flow cytometry. The sigmoidal temporal profile of total counts was obtained by classic haemocytometry and corresponding cell size distributions were measured electronically using a Coulter Counter. A mathematical model recently proposed (1) was adopted for quantitative interpretation of these experimental data. The model is based on a 1-D (that is, mass-structured), single-staged population balance approach capable of taking into account contact inhibition at confluence. The model's parameters were determined by fitting measured total cell counts and size distributions. Model reliability was verified by predicting cell proliferation counts and corresponding size distributions at culture times longer than those used when tuning the model's parameters. It was found that adoption of cell mass as the intrinsic characteristic of a growing chondrocyte population enables sigmoidal temporal profiles of total counts in the Petri dish, as well as cell size distributions at 'balanced growth', to be adequately predicted.

HSP27: mechanisms of cellular protection against neuronal injury

The heat shock protein (HSP) family has long been associated with a generalized cellular stress response, particularly in terms of recognizing and chaperoning misfolded proteins. While HSPs in general appear to be protective, HSP27 has recently emerged as a particularly potent neuroprotectant in a number of diverse neurological disorders, ranging from ALS to stroke. Although its robust protective effect on a number of insults has been recognized, the mechanisms and regulation of HSP27's protective actions are still undergoing intense investigation. On the basis of recent studies, HSP27 appears to have a dynamic and diverse range of function in cellular survival. This review provides a forum to compare and contrast recent literature exploring the protective mechanism and regulation of HSP27, focusing on neurological disorders in particular, as they represent a range from protein aggregate-associated diseases to acute stress.

FSHB subunit gene is associated with major gene controlling litter size in commercial pig breeds

An insertion fragment in porcine FSHbeta subunit gene was cloned by PCR. Sequencing data show that the insertion is a retroposon of 292 bp sitting in intron I at the site between + 809 and +810 base. Based on these results, a PCR programme was created to genotype animal individuals in different pig breeds at FSW locus and polymorphism of FSHbeta gene was analyzed. With the combination of genotype and litter size of sows, it was demonstrated that FSHbeta locus is closely associated with major gene controlling litter size in commercial pig breeds, such as Yorkshire, Landrace, Durco. Averagely the AA sows give more 1.5 piglets than BB sows do per litter.

Experimental analysis and modelling of in vitro proliferation of mesenchymal stem cells

OBJECTIVES

Stem cell therapies based on differentiation of adult or embryonic stem cells into specialized ones appear to be effective for treating several human diseases. This work addresses the mathematical simulation of proliferation kinetics of stem cells.

MATERIALS AND METHODS

Sheep bone marrow mesenchymal stem cells (phenotype characterized by flow cytometry analysis) seeded at different initial concentrations in Petri dishes were expanded to confluence. Sigmoid temporal profiles of total counts obtained through classic haemocytometry were quantitatively interpreted by both a phenomenological logistic equation and a novel model based on a one-dimensional, single-staged population balance approach capable of taking into account contact inhibition at confluence. The models' parameters were determined by comparison with experimental data on population expansion starting from single seeding concentration. Reliability of the models was tested by predicting cell proliferation carried out starting from different seeding concentrations.

RESULTS AND DISCUSSION

It was found that the proposed population balance modelling approach was successful in predicting the experimental data over the whole range of initial cell numbers investigated, while prediction capability of phenomenological logistic equation was more limited.

Biomarkers of infection for the differential diagnosis of pleural effusions

We aimed to investigate whether pleural fluid concentrations of biomarkers for bacterial infection, namely triggering receptor expressed on myeloid cells (sTREM-1), procalcitonin (PCT), lipopolysaccharide-binding protein (LBP) and C-reactive protein (CRP), might identify infectious effusions and discriminate between complicated (CPPEs) and uncomplicated parapneumonic effusions (UPPEs). Stored pleural fluid samples from 308 patients with different causes of pleural effusion were used to measure the four biomarkers. Receiver-operating characteristic analysis determined the accuracy of the new tests. Median pleural fluid levels of CRP, sTREM-1 and LBP were significantly higher in CPPE compared with those in other aetiologies. The area under the curve for distinguishing infectious (parapneumonics and tuberculosis) from noninfectious effusions was 0.87 for CRP, 0.86 for sTREM-1, 0.57 for PCT and 0.87 for LBP. Regarding the discrimination of nonpurulent CPPE versus UPPE, a multivariate analysis found that pleural fluid glucose < or =60 mg x dL(-1), LBP > or =17 microg x mL(-1) and CRP > or =80 mg x L(-1) were the best parameters. Individually, none of the new biomarkers achieved better performance characteristics than pH, glucose or lactate dehydrogenase in labelling CPPE. In conclusion, elevated pleural fluid levels of CRP, sTREM and LBP identify patients with infectious effusions, particularly those with CPPE. PCT has no value for the differential diagnosis of pleural effusions.

A dynamic micro-CT scanner based on a carbon nanotube field emission x-ray source

Current commercial micro-CT scanners have the capability of imaging objects ex vivo with high spatial resolution, but performing in vivo micro-CT on free-breathing small animals is still challenging because their physiological motions are non-periodic and much faster than those of humans. In this paper, we present a prototype physiologically gated micro-computed tomography (micro-CT) scanner based on a carbon nanotube field emission micro-focus x-ray source. The novel x-ray source allows x-ray pulses and imaging sequences to be readily synchronized and gated to non-periodic physiological signals from small animals. The system performance is evaluated using phantoms and sacrificed and anesthetized mice. Prospective respiratory-gated micro-CT images of anesthetized free-breathing mice were collected using this scanner at 50 ms temporal resolution and 6.2 lp mm(-1) at 10% system MTF. The high spatial and temporal resolutions of the micro-CT scanner make it well suited for high-resolution imaging of free-breathing small animals.

Dimensionality-controlled insulator-metal transition and correlated metallic state in 5d transition metal oxides Sr n+1Ir nO3n+1 (n=1, 2, and infinity)

We investigated the electronic structures of the 5d Ruddlesden-Popper series Sr n+1Ir nO3n+1 (n=1, 2, and infinity) using optical spectroscopy and first-principles calculations. As 5d orbitals are spatially more extended than 3d or 4d orbitals, it has been widely accepted that correlation effects are minimal in 5d compounds. However, we observed a Mott insulator-metal transition with a change of bandwidth as we increased n. In addition, the artificially synthesized perovskite SrIrO3 showed a very large mass enhancement of about 6, indicating that it was in a correlated metallic state.

Novel Jeff=1/2 Mott state induced by relativistic spin-orbit coupling in Sr2IrO4

We investigated the electronic structure of 5d transition-metal oxide Sr2IrO4 using angle-resolved photoemission, optical conductivity, x-ray absorption measurements, and first-principles band calculations. The system was found to be well described by novel effective total angular momentum Jeff states, in which the relativistic spin-orbit coupling is fully taken into account under a large crystal field. Despite delocalized Ir 5d states, the Jeff states form such narrow bands that even a small correlation energy leads to the Jeff=1/2 Mott ground state with unique electronic and magnetic behaviors, suggesting a new class of Jeff quantum spin driven correlated-electron phenomena.

Breeding for resistance to mastitis in United Kingdom sheep, a review and economic appraisal

Mastitis is a problem in the sheep industry, and its incidence varies widely with how it is recorded, the breed of sheep and the farm. Virtually all the published information about the genetics of mastitis refers to dairy breeds of cattle and sheep, and there is little information for meat sheep breeds. Many dairy breeding programmes worldwide use the somatic cell count (scc) in milk as an indicator of resistance to clinical and subclinical mastitis, but it is difficult to measure in meat sheep breeds. Molecular genetic technologies may therefore be a more practical way to assess susceptibility to mastitis. This paper reviews the genetics of mastitis and considers the opportunities for breeding for resistance to mastitis, with particular reference to sheep. In addition, to investigate the potential economic effects of mastitis in a purebred sheep population, a computer model of flock dynamics was developed. By making a modest set of assumptions about the key farm parameters that influence lowland sheep production, the model showed that breeding for resistance (or other control methods), if it could reduce the risk of contracting mastitis by 10 per cent, would be worth pounds 8.40 per ewe, equivalent annually to pounds 2.7 million for the purebred sector of the Texel breed alone.

Hypertension in Mexico and among Mexican Americans: prevalence and treatment patterns

Increased social and economic integration across the US-Mexican borders has led to important new developments in public health. Lower levels of cardiovascular mortality have been observed among Mexican Americans (MAs) although few direct comparisons have been undertaken with Mexico. Using survey data in the respective countries we examined blood pressure (BP) levels, hypertension prevalence and patterns of awareness, treatment and control in Mexico and among MAs. A national representative sample of the adult population from Mexico collected in 2000 (N=49 294), and data on 8688 MA participants in the 1999-2004 National Health and Nutrition Examination survey from the United States were available for analysis. US-born MAs and those born in Mexico were analysed separately in the US data. Lack of direct standardization of methods between surveys necessitated statistical adjustment of BP values. Analyses were based on persons aged 25-64 in each country. Sex- and age-adjusted mean systolic/diastolic BPs were 122/80, 119/71 and 120/73 in Mexicans, immigrant MAs and US-born MAs, respectively. The prevalences of hypertension (BP > or = 140/90 or treatment) were 33, 17 and 22%. Hypertension control rates were 3.7, 32.1 and 37.9%, in the same groups. Awareness and treatment rates were 25 and 13% in Mexico and 54 and 46% among MAs in the United States, respectively. Hypertension appears to be more common in Mexico than among Mexican immigrants to the United States. Despite relatively low access to health insurance in the United States, hypertension control increased over the course of this migration.

Observation of strong spin valve effect in bulk Ca3(Ru1-xCrx)2O7

The spin-valve effect is a quantum phenomenon so far only realized in multilayer thin films or heterostructures. Here we report a strong spin-valve effect existing in bulk single crystals of Ca3(Ru1-xCrx)2O7 having an anisotropic, bilayered crystal structure. This discovery opens new avenues to understand the underlying physics of spin valves, and fully realize its potential in practical devices.

Activity, adiposity and weight change in Jamaican adults

OBJECTIVE

Populations in developing countries are particularly vulnerable to the development of obesity in the period of rapid transition to a more modernized lifestyle. We sought to determine the relationship between activity energy expenditure (AEE), adiposity and weight change in an adult population undergoing rapid socio-economic transition.

METHODS

Total daily energy expenditure (TDEE) was measured using the doubly labelled water method, resting energy expenditure (REE) using indirect calorimetry and AEE calculated as the difference between TDEE and REE, in adults from a working class community in Spanish Town, Jamaica. During six years of follow-up, weight was measured between one and four times. Mixed effects regression modelling was used to test for association between components of the energy budget and weight change.

RESULTS

Men (n = 17) weighed more but women (n = 18), had significantly more body fat, 38.5% vs 24.5%, respectively (p < 0.01). Men had higher levels of EE, particularly AEE after adjustment for body weight, 66.3 versus 46.4 kJ/kg.d for men and women, respectively (p < 0.001). At baseline, adjusted AEE was inversely associated with body fat in men and women, r = -0.46 and r = -0.48, respectively (p < 0.05). Mean rate of weight change was + 1.1 and + 1.2 kg/year for men and women, respectively. No component of EE, ie TDEE, REE or AEE, significantly predicted weight change in this small sample.

CONCLUSIONS

These results suggest an important role for AEE in maintaining low levels of adiposity. The lack of association between EE and weight change, however, suggests populations in transition are at risk of obesity from environmental factors (eg dietary) other than simply declining physical activity levels.

Shear waves induced by moving needle in MR elastography

Magnetic resonance elastography (MRE) is a phase contrast-based method for observing shear wave propagation in a material to determine its stiffness. The objective of this study was to determine whether shear waves suitable for MRE could be induced using a moving acupuncture needle. Tissue-simulating bovine gel phantom and a 0.4 mm diameter acupuncture needle were used in the experiment. The results showed that observable shear waves could be induced in the gel phantom by cyclic needle motion. The observed wavelength varied with excitation frequency, as expected. Generating shear waves using moving needles may be a useful tool to study the basic mechanism of acupuncture with MRE. Further study will be conducted to observe the wave motion in inhomogeneous media and acupuncture-induced effects in in-vivo studies.

A Feasibility Study of PZT Thin-Film Microactuators for Hybrid Cochlear Implants

Hybrid cochlear implants would integrate electric and acoustic auditory stimulation into a single unit to rehabilitate patients with sensori-neural hearing loss. Conceptually, hybrid cochlear implants consist of an electrode array, as in traditional cochlear implants, and an acoustic microactuator to generate pressure waves inside the cochlea. To enable hybrid cochlear implants, one must develop acoustic actuators small enough to be placed directly into the cochlea. In this study, the microactuators consist of a silicon diaphragm and a Lead-Zirconate-Titanate Oxide (PZT) thin film. Two actuators are tested. For the first actuator, the diaphragm size is 1.1 mm by 1.1 mm, the diaphragm thickness is about 12 m, and the PZT film thickness is 1 &#956;m. The microactuator is tested in an unloaded condition (in air) and a loaded condition (with water and glass sheets) equivalent to a loading of 17 Pa. The microactuator presents a constant displacement of 16 nm, when the driving voltage is sinusoidal with amplitude of 5 V and frequency ranging from 500 Hz to 10 kHz. For the second actuator, the diaphragm size is 800 &#956;m by 800 &#956;m, the diaphragm thickness is 1 &#956;m, and the PZT film thickness remains 1 m. The second actuator presents a displacement of 6 nm, when the sinusoidal driving voltage is 7.5 V in amplitude. Given that the motion of the stapes in normal hearing is 10-30 nm when the incoming sound pressure is 1 Pa (i.e.

Conversion from cyclosporine to mycophenolate mofetil improves expression of A20 in the rat kidney allografts undergoing chronic rejection

AIMS

Cytoprotective genes have shown to display potent anti-inflammatory and antiapoptotic functions in endothelial and smooth muscle cells. We investigated whether cytoprotective genes, especially A20, were involved in mycophenolate mofetil (MMF)'s ability to ameliorate transplant arteriosclerosis in an experimental chronic rejection model.

METHODS

Sprague-Dawley rat renal grafts were orthotopically transplanted into Wistar rats following the procedure of Kamada with our modification. The recipients were divided into three oral treatment groups: (1) vehicle group (cyclosporine [CsA] 10 mg/kg.d x 10 d followed by vehicle), (2) CsA group (CsA 10 mg/kg.d x 10 d followed by CsA 6 mg/kg.d), (3) MMF group (converted from CsA 10 mg/kg.d x 10 d to MMF 20 mg/kg.d on day 11). At the same time points after transplantation, the rats were sacrificed to harvest the renal allografts. The expression of four cytoprotective genes, A20, heme oxygenase (HO)-1, Bcl-2, and Bcl-XL, was analyzed by quantitative reverse-transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

The four-cytoprotective genes were all detected in rat kidney allografts undergoing chronic allograft nephropathy. The expression of A20 in grafted kidneys was significantly higher in the MMF than in the CsA or the vehicle group (P < .01). There was no significant difference between the CsA and the MMF groups in the expression of HO-1, Bcl-2, and Bcl-XL.

CONCLUSIONS

We demonstrated that MMF improved the expression of A20 in rat kidney allografts undergoing chronic allograft nephropathy. The correlation between MMF and A20 provide an explanation for the mechanism by which MMF ameliorates transplant arteriosclerosis in an experimental animal model of chronic rejection.

Expression of fractalkine, CX3CR1, and vascular endothelial growth factor in human chronic renal allograft rejection

AIM

Fractalkine/CX3CR1 system may contribute to the pathogenesis of renal allograft chronic rejection (CR). Vascular endothelial growth factor (VEGF) is an endothelial mitogen, which shows increased expression in inflammation and vasculopathy. This study sought describe the expression and distribution of Fractalkine/CX3CR1 and VEGF, and their relationship to human renal allograft CR.

METHODS

Renal tissue from 10 patients with CR was examined for Fractalkine/CX3CR1 and VEGF protein by immunohistochemistry for comparison with patients displaying hyperacute rejection (n = 10), acute rejection (n = 10), and normal kidneys (n = 10). All patients were selected based upon histologically proven diagnoses between 1992 and 2003.

RESULTS

Immunohistochemistry revealed that Fractalkine/CX3CR1 were mostly expressed in the tubulointerstitium and tubular epithelial cell basolateral membrane. Some vessels showed positive staining for Fractalkine/CX3CR1 as well as occasionally glomerular parietal wall cells. Among the CR group, VEGF was mostly expressed in tubular epithelium and the tubulointerstitium. A proportion of glomeruli and vessels had positive staining for VEGF, which was up-regulated most strikingly in the interstitial compartment in CR. There was markedly increased expression of Fractalkine/CX3CR1 and VEGF protein in the interstitium of the CR compared with other groups (P < .05). VEGF colocalized with the expression of Fractalkine/CX3CR1.

CONCLUSION

Fractalkine/CX3CR1 and VEGF may play an important role in the development of interstitial fibrosis via mononuclear cell-induced cytokine production and myofibroblast stimulation in CR. Further studies are necessary to identify the role in the pathogenesis of CR.

Comparison of cyclosporine versus mycophenolate mofetil on expression of Fractalkine and CX3CR1 in chronic allograft nephropathy

INTRODUCTION

We sought to investigate whether there was a difference between cyclosporine (CsA) and mycophenolate mofetil (MMF) to affect the expression of Fractalkine/CX3CR1 in chronic allograft nephropathy (CAN).

METHODS

The Sprague-Dawley Wistar rat accelerated kidney sclerosis model was performed as modified from the procedure of Kamada. Recipients were divided into three oral treatment groups (each group n = 8): group A was CsA 10 mg/kg . d for 10 days followed by vehicle; group B was CsA 10 mg/kg . d for 10 days followed by CsA 6 mg/kg.d; group C was CsA 10 mg/kg . d for 10 days followed by MMF 20 mg/kg . d. Pathological changes graded according to Banff 97 Standards were observed at 4, 8, and 12 weeks posttransplantation. The immunohistochemistry and quantitative real-time fluorescence polymerase chain reaction (PCR) were used to assess the distribution and expression of Fractalkine/CX3CR1 in the grafted kidney.

RESULTS

Fractalkine/CX3CR1 were mostly expressed in the tubulointerstitium and tubular epithelial cell basolateral membrane. A proportion of the vessel showed positive staining for Fractalkine/CX3CR1, occasionally in glomerular parietal wall cells. The expression of Fractalkine/CX3CR1 in grafted kidneys at all the time points was significantly less in the MMF than in the CsA group or the control group (P < .05). Real-time fluorescence quantitative PCR revealed similar outcomes as immunohistochemistry. The expression of Fractalkine coincided with CX3CR1.

CONCLUSION

Fractalkine/CX3CR1 may play an important role in the development of interstitial fibrosis in CAN. Different immunosuppressants have various effects on expression of the Fractalkine/CX3CR1.

Comparison of rapamycin versus FK506 on expression of cytoprotective genes in the rat kidney allografts undergoing chronic allograft nephropathy

AIMS

It is increasingly recognized that expression of cytoprotective genes in grafts can affect the progress of chronic allograft nephropathy (CAN). Little is known about the influence of different immunosuppressive regimens on expression of cytoprotective genes in allografts undergoing CAN. We investigate whether there is difference between rapamycin (Rapa) and FK506 in the expression of cytoprotective genes in rat kidney allografts undergoing CAN.

METHODS

Sprague-Dawley rat renal grafts were orthotopically transplanted into Wistar rats following the procedure of Kamada with our modification. The recipients were divided into three oral treatment groups: group 1: vehicle group (cyclosporine [CsA] 10 mg/kg.dx 10 days followed by vehicle); group 2: Rapa group (CsA 10 mg/kg.d x 10 d followed by Rapa 0.8 mg/kg.d); group 3: FK506 group (CsA 10 mg/kg.d x 10 d followed by FK506 0.15 mg/kg.d). At the same times after transplantation, the rats were sacrificed to harvest the renal allografts. The expression of four cytoprotective genes, A20, heme oxygenase (HO)-1, Bcl-2, and Bcl-X/L were analyzed in these grafted kidneys by quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry.

RESULTS

Four cytoprotective genes were all detected in rat kidney allografts undergoing CAN. The expression of A20 in the Rapa group was significantly higher than that in the FK506 or the vehicle group (P < .05). There was no significant difference between the Rapa group and FK506 group in the expressions of HO-1, Bcl-2, and Bcl-X/L.

CONCLUSIONS

We demonstrate that various immunosuppressive agents have different effects on the expression of cytoprotective genes.

Acute sodium overload produces renal tubulointerstitial inflammation in normal rats

The aim of the present study was to determine whether acute sodium overload could trigger an inflammatory reaction in the tubulointerstitial (TI) compartment in normal rats. Four groups of Sprague-Dawley rats received increasing NaCl concentrations by intravenous infusion. Control (C): Na+ 0.15 M; G1: Na+ 0.5 M; G2: Na+ 1.0 M; and G3: Na+ 1.5 M. Creatinine clearance, mean arterial pressure (MAP), renal blood flow (RBF), and sodium fractional excretion were determined. Transforming growth factor beta1 (TGF-beta1), alpha-smooth muscle actin (alpha-SMA), RANTES, transcription factor nuclear factor-kappa B (NF-kappaB), and angiotensin II (ANG II) were evaluated in kidneys by immunohistochemistry. Animals with NaCl overload showed normal glomerular function without MAP and RBF modifications and exhibited a concentration-dependent natriuretic response. Plasmatic sodium increased in G2 (P < 0.01) and G3 (P < 0.001). Light microscopy did not show renal morphological damage. Immunohistochemistry revealed an increased number of ANG II-positive tubular cells in G2 and G3, and positive immunostaining for NF-kappaB only in G3 (P < 0.01). Increased staining of alpha-SMA in the interstitium (P < 0.01), TGF-beta1 in tubular cells (P < 0.01), and a significant percentage (P < 0.01) of positive immunostaining for RANTES in tubular epithelium and in glomerular and peritubular endothelium were detected in G3 > G2 > C group. These results suggest that an acute sodium overload is able 'per se' to initiate TI endothelial inflammatory reaction (glomerular and peritubular) and incipient fibrosis in normal rats, independently of hemodynamic modifications. Furthermore, these findings are consistent with the possibility that activation of NF-kappaB and local ANG II may be involved in the pathway of this inflammatory process.

Schistosoma japonicum triose-phosphate isomerase plasmid DNA vaccine protects pigs against challenge infection

The protective efficacy of a Schistosoma japonicum, Chinese strain, triose-phosphate isomerase (TPI) plasmid DNA vaccine was examined in naïve pigs. Pigs were vaccinated with the TPI DNA-plasmid alone, or in conjunction with IL-12 as pcDNA3.1-P35, pcDNA3.1-P40 plasmids via intramuscular injection. Control pigs were immunized with equivalent amounts of pcDNA3.1. Pigs were immunized 3 times at 21-day intervals and challenged 30 days after the final boost. Forty-five days post-challenge, pigs were sacrificed and perfused to compare adult worm burdens, female worm burdens, liver egg burdens and granuloma size. We found that pigs vaccinated with SjCTPI DNA alone had adult worm burdens reduced by 48.3% and that a further decrease in adult worm burdens was not seen in the group vaccinated with SjCTPI DNA in conjunction with IL-12 (46.2% reduction). The SjCTPI DNA vaccines had a more pronounced effect on reducing female worm burdens i.e. 53.6% SjCTPI alone and 59.6% for SjCTPI+IL-12. Vaccination with SjCTPI-DNA reduced liver eggs by 49.4% and this response was significantly enhanced by the addition of IL-12 (65.8% reduction in liver eggs). In addition to the dramatic protective effects seen in vaccinated pigs, we also noted that granuloma size was reduced by 42% in both groups. Thus, vaccination of pigs and other large animals in China with SjCTPI DNA vaccine will likely reduce transmission by reducing adult worm burdens and worm egg output and simultaneously reduce hepatic egg-associated pathology.

Mechanically induced self-propagating reactions: analysis of reactive substrates and degradation of aromatic sulfonic pollutants

Mechanochemical reactions have been identified as a valuable alternative to conventional methodologies for the degradation of toxic pollutants as well as for their abatement in contaminated matrices. This paper discusses the application of the mechanochemical technique to the degradation of sulfonic acids in a contaminated matrix. The degradation of the pollutant compound was carried out by taking advantage of combustive reactions on a suitable reactive system ignited under mechanical treatment conditions. Two systems have been investigated as possible reactive substrates. The first one was a Mg-SiO2 powder mixture while the second system was a Ca-SiO2 powder mixture. Milling trials performed under different mechanical processing conditions allowed one to characterise the reactivity of these chemical systems, which basically undergo a reduction/oxidation reaction involving the formation of MgO and Si phases when the Mg-SiO2 system is considered and CaO and Si phases when the Ca-SiO2 system is employed, respectively. The systematic change of the stoichiometric ratios Mg:SiO2 and Ca:SiO2 permitted to identify the minimum Mg or Ca content necessary for the ignition of the combustive reactions. The experimental runs performed with such systems have shown a greater effectiveness of the Mg-SiO2 because of less energy inputs required to ignite a combustion. For this reason the Mg-SiO2 has been considered as a reactive substrate in the following trials. Since the SiO2 amount in stoichiometric excess may be regarded as inert phase, it was substituted with a different phase consisting of the matrix contaminated by sulfonic acids. This aspect permitted to ignite a combustive reaction with the minimum possible content of Mg-SiO2 reacting mixture. The chemical analyses performed after the combustive reaction proved the complete removal of the sulfonic acid from the contaminated matrix.

Mobility of heavy metals from tailings to stream waters in a mining activity contaminated site

In this paper the results of a recent characterization of Rio Piscinas (SW of Sardinia, Italy) hydrological basin are reported. In such area (about 50 km2), previous mining activities caused a serious heavy metal contamination of surface waters, groundwater, soils and biota. Acid mine drainage phenomena were observed in the area. The main sources of contamination are the tailings stored in mine tunnels and abandoned along fluvial banks. A methodological approach was adopted in order to identify relations between tailings and water contamination. Representative samples of tailings and stream sediments samples were collected. XRD analyses were performed for mineralogical characterization, while acid digestion was carried out for determining metal contents. Batch sequential leaching tests were performed in order to assess metal mobility. Also groundwater and stream water were sampled in specific locations and suitably characterized. All information collected allowed the understanding of the effect of tailings on water contamination, thus contributing to the qualitative prediction of pollution evolution on the basis of metal mobility. Finally, a potential remediation strategy of stream water is proposed.

Field- and pressure-induced phases in Sr4Ru3O10: a spectroscopic investigation

We have investigated the magnetic-field- and pressure-induced structural and magnetic phases of the triple-layer ruthenate Sr4Ru3O10. Magnetic-field-induced changes in the phonon spectra reveal dramatic spin-reorientation transitions and strong magnetoelastic coupling in this material. Further, we are able to deduce key magnetoelastic coupling parameters, and evidence that the magnetic moments are localized on the Ru sites. Additionally, pressure-dependent Raman measurements at different temperatures reveal an anomalous negative Gruneisen parameter associated with the B(1g) mode (approximately 380 cm(-1)) at low temperatures (T < 75 K), which can be explained consistently with the field-dependent Raman data.

Hypoxic-ischemic brain injury in the neonatal rat model: relationship between lesion size at early MR imaging and irreversible infarction

BACKGROUND AND PURPOSE

By using a neonatal rat hypoxia-ischemia (HI) model, we studied the relationship between lesion volume-measured by diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) at an early time point-and irreversible infarct volume. We also evaluated the optimal apparent diffusion coefficient (ADC) threshold that provides the best correlation with irreversible infarct size.

MATERIALS AND METHODS

Twenty-three neonatal rats underwent right common carotid artery ligation and hypoxia. MR imaging was performed 1-2 hours post-HI by using DWI and T2WI and at day 4 post-HI by using T2WI. Lesion volumes relative to whole brain (%LV) were measured on ADC maps by using different relative ADC thresholds 60%-80% of mean contralateral ADC and T2WI. Pearson correlation and multiple linear regression analysis were used to study the relationships between ln(%LV) at MR imaging and %LV at histopathology.

RESULTS

At 1-2 hours post-HI, all lesion volume measurements on DWI were significantly correlated with the infarct volume on histopathology, with the best correlation attained at the 80% ADC threshold (r = 0.738; P < .001). The estimated regression formula was %LV on histopathology = 20.60 + 3.33 ln(%LV on 80% ADC threshold) (adjusted R(2) = 0.523; P < .001). Lesion volume at 1-2 hours post-HI tended to underestimate the final infarct volume.

CONCLUSION

Early post-HI MR imaging by using DWI correlates moderately well with the size of irreversible infarct, especially when measured by using a relative ADC threshold of 80% mean contralateral ADC.

Relative hypoparathyroidism induced by interferon treatment in a hemodialysis patient

Several authors have documented beneficial effects of interferon (IFN) in chronic hepatitis C virus (HCV) infection among the dialysis population. Reports about mineral metabolism disturbances during IFN treatment are scarce, especially in dialysis patients. We report the case of a 49-year-old woman on hemodialysis with chronic HCV infection who developed significant decrease in serum calcium (Ca) and phosphorus (P) levels accompanied by relative hypoparathyroidism while being under treatment with alpha-IFN. These changes were closely related to IFN treatment, because they disappeared after INF was discontinued, reaching Ca and P levels which were similar to those of the pre-IFN period. Because IFN may induce immune disorders, several autoimmune markers were analyzed. All of them were negative or within the normal range. To further explore these mineral metabolism disturbances, a number ofparathyroid hormone (PTH) secretion-inhibiting factors, such as aluminum, magnesium, 25-hydroxyvitamin D, and calcitriol were excluded as a cause for these changes. We suggest that mineral metabolism should be carefully observed during interferon treatment in dialysis patients.

Colossal magnetoresistance by avoiding a ferromagnetic state in the Mott system Ca3Ru2O7

Transport and magnetic studies of Ca3Ru2O7 for temperatures ranging from 0.4 to 56 K and magnetic fields B up to 45 T lead to strikingly different behavior when the field is applied along the different crystal axes. A ferromagnetic (FM) state with full spin polarization is achieved for the B//a axis, but colossal magnetoresistance is realized only for the B//b axis. For the B//c axis, Shubnikov-de Haas oscillations are observed and followed by a less resistive state than that for B//a. Hence, in contrast with standard colossal magnetoresistive materials, the FM phase is the least favorable for electron hopping. These properties together with highly unusual spin-charge-lattice coupling near the Mott transition (48 K) are driven by the orbital degrees of freedom.

Antioxidant capacity of the neurohormone melatonin

The aim of this study was to elucidate the antioxidant behaviour of melatonin (M) and determine its activity-structure relationship. M or 5-metoxy-N acetyltriptamine is a neurohormone secreted by the pineal gland, which plays a proven role in maintaining sleep-wake rhythms. The antioxidant capacity of M was analysed using the oxygen radical absorbance capacity (ORAC) assay. Furthermore, spectral measurements for aerobic photolytic reaction of neutral red (NR) and degree of inhibition of photolysis with M, glutathione (GSH), ascorbic acid (AA) and vitamin E analogue Trolox were studied at room temperature 25 degrees C, using visible (VIS) and ultra-violet (UV) radiations. In the ORAC assay 2,2-azobis (2-amidino-propane)dihydrochloride (AAPH) a peroxyl radical generator, ROO degrees ; H2O2-Cu2+, mainly a hydroxyl radical generator, degrees OH; and Cu2+ a transition metal were used. Although some studies indicated that M is a powerful antioxidant, no one has compared its antioxidant capacities with GSH, E-vitamin and AA, using three free radical (FR) generators in an assay which utilizes an area-under curve technique and thus combines both inhibition time and inhibition degree of FR action by an antioxidant into a single quantity. In the current study, we used ORAC assay with three FR generators. The assay is based on propensity of the fluorescence emitted by the protein beta-phycoerythrin (beta-PE) from porphyridium cruentum to be quenched when exposed to FR action. M in our experiments acted as a universal antioxidant against ROO degrees and degrees OH radicals. Also, M served as an antioxidant in the presence of Cu2+. M, which is a lipid-soluble compound, was a twice more powerful antioxidant than vitamin E, and four times than AA or GSH. Furthermore, M inhibited aerobic photolysis of NR photoinduced with VIS and UV rays faster and more effectively, than AA, GSH or vitamin E. AA with NR, under aerobic conditions during irradiation with VIS and UV acted as a pro-oxidant. M may be the premier molecule to protect the cells from oxidative stress.

Reduced cardiac expression of plasminogen activator inhibitor 1 and transforming growth factor beta1 in obese Zucker rats by perindopril

OBJECTIVE

To determine whether angiotensin converting enzyme inhibition by perindopril can reduce cardiac transforming growth factor beta1 (TGFbeta1) and plasminogen activator inhibitor 1 (PAI-1) and therefore control collagen accumulation in an animal model with the metabolic syndrome such as the obese Zucker rat (OZR).

ANIMALS

Male OZR (group 1, n = 10); OZR treated with perindopril (group 2, n = 10); and lean Zucker rats (group 3, n = 10).

METHODS

During six months, group 2 received 3 mg/kg/day of perindopril orally and group 1 and group 3 were given a vehicle. Hearts were processed for pathology studies including immunohistochemical analysis with antibodies to PAI-1, TGFbeta1, collagen type I, and collagen type III.

RESULTS

Group 2 had lower blood pressure (126.7 (2) v 148.6 (2.7) mm Hg, p < 0.01) than untreated OZR and had decreased cardiac PAI-1 (3.6 (0.4) v 13.5 (1.7)% of positive area/field, p < 0.01), TGFbeta1 in myocytes (0.13 (0.1) v 9.14 (4.7)%/area, p < 0.01) and in interstitium (19.8 (6.8) v 178.9 (27.4) positive cells/area, p < 0.01), collagen I (3 (0.8) v 13.3 (1)%/area, p < 0.01), collagen III (5 (0.6) v 9.5 (0.9)%/area, p < 0.01), and collagen I to collagen III ratio (0.59 (0.13) v 1.40 (0.15) p < 0.01) compared with untreated OZR.

CONCLUSION

These results suggest that perindopril reduces cardiac PAI-1 and TGFbeta1 and ameliorates cardiac fibrosis in a rat model with multiple cardiovascular risk factors.

Field-induced orbital and magnetic phases in Ca3Ru2O7

Magnetic-field- and temperature-dependent Raman scattering studies of Ca3Ru2O7 reveal dramatic field-dependent properties arising from transitions between various complex orbital and magnetic phases, including a field-induced orbital-ordered to orbital-disordered transition (H(o) // hard axis), and a reentrant orbital-ordered to orbital-disordered to orbital-ordered transition (H(o) // easy axis). We find that the dramatic magnetic-field properties are most prevalent in a "mixed"-magnetic and -orbital phase regime, providing evidence for a strong connection between orbital phase inhomogeneity and "colossal" field effects in the ruthenates.

Once‐a‐Day Controlled‐Release Dosage Form of Divalproex Sodium II: Development of a Predictive In Vitro Drug Release Method

During formulation design of a once-daily controlled release matrix system of divalproex sodium, the in vitro dissolution test (USP II, 100 rpm, pH 6.8 buffer) was found to result in release rates that were slower than in vivo absorption. The test method also did not sufficiently discriminate formulations with different in vivo absorption rates. To develop an in vitro method that is directly correlated with in vivo absorption, statistically designed studies were carried out to investigate the effects of various in vitro testing variables on drug release using USP dissolution apparatuses. The variables studied included agitation intensity, apparatus, pH, surfactant and ionic strength of the dissolution medium. Experimental data were analyzed using ANOVA. In vitro/in vivo correlation was tested based on the hypothesis that the same linear regression equation holds for three formulations with different release rates. A mixed effects model was used in which the dependence among observations from the same subject was taken into account. Factorial studies indicated that higher pH, addition of sodium lauryl sulphate (SLS) to the dissolution medium, and higher agitation intensity increased the release rate from the matrix tablet. Use of SLS not only lead to increased release rates that are more comparable to in vivo absorption rates, but also improved differentiation among formulations with varying release rates. Furthermore, drug release was also affected by interactions among the variables studied. Statistical analysis indicated that a combination of higher SLS concentration and lower pH provided enhanced differentiation between release profiles of the fast and slow releasing formulations. Based on the above findings, a new set of testing conditions was identified and demonstrated to be predictive of in vivo drug absorption for various controlled release formulations of divalproex sodium. The new method uses USP Apparatus II operating at 100 rpm in 500 mL of 0.1 N HCl for 45 min followed by 900 mL of 0.05 M phosphate buffer containing 75 mM SLS, pH 5.5, 37 +/- 0.5 degrees C. In conclusion, adjusting dissolution testing conditions to match the behavior of the formulations in vitro with that in vivo is a useful approach in identifying a predictive method in development of in vitro-in vivo correlation.

Morphological modifications in clitoris and vagina in spontaneously hypertensive rats

We evaluated possible morphological alteration in clitoris and vagina from spontaneous hypertensive rats (SHR) and normotensive WKY rats. Clitoris and vagina were processed by Masson's trichrome, anti-alpha-smooth-muscle actin, anticollagen type I (COL I) and type III (COL III), and anti-TGFbeta(1). SHR presented higher amount of clitoral cavernous smooth muscle (CSM), vascular smooth muscle; TGFbeta(1) in clitoral vessel wall; higher wall/lumen ratio in both vaginal and clitoral vessels; and remarkable interstitial fibrosis, expressed by a higher amount in interstitial COL I and III in both clitoris and vagina, compared to WKY rats. Nerve fibers from clitoral and vaginal tissue in SHR showed important fibrosis at perineurium. SHR showed positive correlation between systolic blood pressure (SBP) and clitoral CSM; SBP and fibrosis in clitoris; and SBP and COL I and III in clitoris, respectively. Similar findings were observed between SBP and COL I and III in vagina. In conclusion, SHR present morphologic changes in clitoral vessels as well as in clitoral cavernous space, which have a high positive correlation with the high blood pressure level. Moreover, the increase in extracellular matrix affects not only the clitoral and vaginal interstitium but also the nerve structures from both clitoris and vagina.