Adsorption of phenylalanine on layered double hydroxides: effect of temperature and ionic strength

In this work we report the adsorption of phenylalanine (Phe) on Magnesium Aluminum Layered Double Hydroxides (Mg-Al-CO(3)-LDH) at two different temperatures (298 and 310 K) and under two distinct ionic strength conditions (with and without the addition 0.1 M of NaCl). The adsorption isotherms exhibit the same profile in all conditions, and they only differ in the amount of removed Phe. At lower ionic strength, the isotherms are almost identical at both temperatures, except for the last points, where the increase in temperature causes a decrease in the amount of adsorbed Phe. An increase in ionic strength results in a decrease in Phe adsorption. The electrokinetic potential decreases as the amount of adsorbed Phe increases, and only positive values are observed. This indicates that the surface of the adsorbent is not totally neutralized and suggests that more Phe could be removed by adsorption. The presence of Phe on the solid is confirmed by FTIR spectra, which present the specific bands assigned to Phe. The hydrophobicity of the amino acid probably contributes to its extraction, thus enabling the removal of a great amount of Phe. In conclusion, LDH is potentially applicable in the removal of Phe from wastewater.

Effect of Diode-Laser and AC Magnetic Field of Bovine Serum Albumin Nanospheres Loaded with Phthalocyanine and Magnetic Particles

This study reports on the development and characterization of bovine serum albumin (BSA) nanospheres containing Silicon(IV) phthalocyanine (NzPc) and/or maghemite nanoparticles (MNP), the latter introduced via ionic magnetic fluid (MF). The nanosized BSA-loaded samples were designed for synergic application while combining Photodynamic Therapy and Hyperthermia. Incorporation of MNP in the albumin-based template, allowing full control of the magnetic content, was accomplished by adding a highly-stable ionic magnetic fluid sample to the albumin suspension, following heat denaturing. The material`s evaluation was performed using Zeta potential measurements and scanning electron microscopy. The samples were characterized by steady-state techniques and time-resolved fluorescence. The in vitro assay, using human fibroblasts, revealed no cytotoxic effect in all samples investigated, demonstrating the potential of the tested system as a synergistic drug delivery system.

Effect of sodium dodecylbenzene sulfonate on the motion of three-phase contact lines on the Wilhelmy plate surface

The combined approach of the molecular-kinetic and hydrodynamic theories for description of the motion of three-phase gas-liquid-solid contact lines has been examined using the Wilhelmy plate method. The whole dynamic meniscus has been divided into molecular, hydrodynamic, and static-like regions. The Young-Laplace equation and the molecular-kinetic and hydrodynamic dewetting theories have been applied to describe the meniscus profiles and contact angle. The dissipative forces accompanying the dynamic dewetting have also been investigated. The experiments with a Wilhelmy plate made from an acrylic polymer sheet were carried out using a computerized apparatus for contact angle analysis (OCA 20, DataPhysics, Germany). The extrapolated dynamic contact angle versus velocity of the three-phase contact line for Milli-Q water and 5 x 10(-4) M SDBS solution was experimentally obtained and compared with the combined MHD models with low and moderate Reynolds numbers. The models predict similar results for the extrapolated contact angle. SDBS decreases the equilibrium contact angle and increases the molecular jumping length but does not affect the molecular frequency significantly. The hydrodynamic deformation of the meniscus, viscous dissipation, and friction were also influenced by the SDBS surfactant. (c) 2005 Elsevier Inc. All rights reserved.

Effect of the immunosuppressants on hepatocyte proliferation and apoptosis in a young animal model of liver regeneration: An immunohistochemical study using tissue microarrays

Hepatocyte proliferation and apoptosis (programmed cell death) occur during the liver parenchyma regeneration and the liver size modeling is mainly controlled by hepatocyte apoptosis. The purpose of the present study was to verify the influence of immunosuppressant drugs on these phenomena by utilizing tissue microarray techniques. Thirty-six weaning rats (age 21-23 days, weight 30-50 g) were divided into six groups: control, sham, hepatectomy, hepatectomy plus solumedrol, hepatectomy plus CsA, and hepatectomy plus Tac. The animals were killed one day after hepatectomy, and the remnant livers were weighed and harvested for tissue microarray sections. Liver cell proliferation was evaluated by staining for PCNA and apoptosis was detected by the TUNEL method. It was verified that CsA promoted a decrease in the liver weight, Tac and CsA decreased the proliferation index of hepatocytes, and glucocorticoid had no significant effects. The apoptosis index was not altered by hepatectomy or immunosuppressants. Our data indicate that, in the growing rat, CsA and Tac have negative effects on hepatocyte proliferation and have no effect on the hepatocyte apoptosis.

Effect of a continuous regimen of contraceptive combination of ethinylestradiol and drospirenone on lipid, carbohydrate and coagulation profiles

Background: The objective of this study was to evaluate the effects of a contraceptive pill containing ethinylestradiol (30 mcg) and drospirenone (3 mg) in a continuous regimen on lipid, carbohydrate and coagulation parameters. Study Design: This open, prospective, randomized study included 78 participants (mean age 27.8 years) who were randomized into two groups to use the pill continuously for 168 days or for six 28-day cycles with a 7-day hormone-free interval between cycles. Markers of lipid, carbohydrate and coagulation profiles were measured prior to initiation and after the 6 months of pill use. Results: No statistically significant differences were found between the two contraceptive regimens with respect to carbohydrate or lipid profiles or in the parameters related to coagulation. Conclusions: The contraceptive combination of ethinylestradiol and drospirenone used in a continuous regimen was associated with metabolic alterations similar to those found during the traditional cyclic regimen of oral contraceptive use. (C) 2010 Elsevier Inc. All rights reserved.

Effect of phosphate binders on oxidative stress and inflammation markers in hemodialysis patients

It has been suggested that phosphate binders may reduce the inflammatory state of hemodialysis (HD) patients. However, it is not clear whether it has any effect on oxidative stress. The objective of this study was to evaluate the effect of sevelamer hydrochloride (SH) and calcium acetate (CA) on oxidative stress and inflammation markers in HD patients. Hemodialysis patients were randomly assigned to therapy with SH (n=17) or CA (n=14) for 1 year. Before the initiation of therapy (baseline) and at 12 months, we measured in vitro reactive oxygen species (ROS) production by stimulated and unstimulated polymorphonuclear neutrophils and serum levels of tumor necrosis factor alpha, interleukin-10, C-reactive protein, and albumin. There was a significant reduction of spontaneous ROS production in both groups after 12 months of therapy. There was a significant decrease of Staphylococcus aureus stimulated ROS production in the SH group. There was a significant increase in albumin serum levels only in the SH group. In the SH group, there was also a decrease in the serum levels of tumor necrosis factor alpha and C-reactive protein. Our results suggest that compared with CA treatment, SH may lead to a reduction in oxidative stress and inflammation. Therefore, it is possible that phosphate binders exert pleiotropic effects on oxidative stress and inflammation, which could contribute toward decreasing endothelial injury in patients in HD.

Effect of Musculoskeletal Pain on Sexuality of Male Adolescents and. Adults with Juvenile Idiopathic Arthritis

Objective. To develop a questionnaire for the evaluation of sexuality of male patients with juvenile idiopathic arthritis (JIA). Methods. A cohort of male patients with rheumatoid factor (RF)-negative polyarticular. JIA according to the 2004 revised ILAR criteria and inactive disease was Studied. The Health Assessment Questionnaire (HAQ) was applied to all patients. As a control group, 120 age-matched males of the same socioeconomic status were evaluated. A self-administered Structured instrument, the Male Sexual Evaluation Questionnaire (MSEQ), was developed by multiprofessional experts to assess sexual life, including satisfaction, practice. and related functional aspects. Results. Thirty-two male patients with RF-negative polyarticular JIA [mean age 20.8 +/- 3.8 yrs (range 16-26), mean disease duration 15.4 +/- 3.6 yrs (range 13-20)] were studied. Mean HAQ score was 1.25 +/- 0.67 (range 0.1-2.1). Masturbation was practiced similarly by patients and controls (87.5% vs 91%; p > 0.999), although joint pain was observed in only 2 (7%) patients. Regular sexual intercourse (>= once/week) was reported by 78% of patients and 62% of controls (p = 0.86). Joint pain during intercourse was more frequent in patients (48% vs 3% in controls; p < 0.001). The mean HAQ score was higher in the 12 patients with,joint pain (hips = 3, knees = 5, and hips + knees = 4) during intercourse compared to the 13 patients without joint pain (1.82 +/- 0.27 vs 1.43 +/- 0.32; p < 0.05). Preserved desire and satisfaction were universal findings for all JIA patients and controls. Conclusion. The MSEQ was applicable to this cohort of male patients with RF-negative polyarticular JIA and showed that sexual life is preserved despite longterm disease, morbidity/functional dysfunction, and joint pain. (First Release May 1 2009: J Rheumatol 2009;36: 1337-42; doi: 10.3899/jrheum.080867)

Effect of hypothalamo-pituitary disconnection on the development of anterior pituitary cells in late gestation ovine fetuses

The specific role of the hypothalamus in regulating the developmental profile of anterior pituitary (AP) cells remains largely unknown. The present study evaluated hypothalamic contributions to AP cell development, utilizing the technique of hypothalamo-pituitary disconnection (HPD). HPD of fetal sheep or sham surgery was performed at 110 days gestation (d) (n=6 each group; term ~ 147d). Fetuses were removed and pituitaries collected at 110d (no surgery; n=6) or 141d (sham and HPD groups). The impact of HPD on AP cell development was assessed by single-labeled immunofluorescence for five hormones to identify proportions of AP cells expressing each hormone. HPD was associated with a 70% increase (P

Extraadrenal 21-Hydroxylation by CYP2C19 and CYP3A4: Effect on 21-Hydroxylase Deficiency

Context: 21-Hydroxylase deficiency (21OHD) is caused by CYP21A2 gene mutations disrupting the adrenal 21-hydroxylase, P450c21. CYP21A2 mutations generally correlate well with the 21OHD phenotype, but some children with severe CYP21A2 mutations have residual 21-hydroxylase activity. Some hepatic P450 enzymes can 21-hydroxylate progesterone, but their physiological relevance in modifying 21OHD is not known. Objective: Wedetermined the ability of CYP2C19 and CYP3A4 to 21-hydroxylate progesterone and 17-hydroxyprogesterone (17OHP), determined the impact of the common P450 oxidoreductase (POR) variant A503V on these activities, and examined correlations between CYP2C19 variants and phenotype in patients with 21OHD. Methods: Bacterially expressed, N-terminally modified, C-His-tagged human P450c21, CYP2C19, and CYP3A4 were combined with bacterially expressed wild-type and A503V POR. The 21-hydroxylation of radiolabeled progesterone and 17OHP was assessed, and the Michaelis constant (Km) and maximum velocity (Vmax) of the reactions were measured. CYP2C19 was genotyped in 21OHD patients with genotypes predicting severe congenital adrenal hyperplasia. Results: Compared to P450c21, the Vmax/Km for 21-hydroxylation of progesterone by CYP2C19 and CYP3A4 were 17 and 10%, respectively. With both forms of POR, the Km for P450c21 was approximately 2.6 mu M, the Km for CYP2C19 was approximately 11 mu M, and the Km for CYP3A4 was approximately 110 mu M. Neither CYP2C19 nor CYP3A4 could 21-hydroxylate 17OHP. The CYP2C19 ultrametabolizer allele CYP2C19* 17 was homozygous in one of five patients with a 21OHD phenotype that was milder than predicted by the CYP21A2 genotype. Conclusions: CYP2C19 and CYP3A4 can 21-hydroxylate progesterone but not 17OHP, possibly ameliorating mineralocorticoid deficiency, but not glucocorticoid deficiency. Multiple enzymes probably contribute to extraadrenal 21-hydroxylation. (J Clin Endocrinol Metab 94: 89-95, 2009)

Fluoxetine effect on kidney water reabsorption

Background. The pathogenesis of hyponatraemia caused by fluoxetine (Fx) use in the treatment of depression is not well understood. It has been attributed to a SIADH, although ADH-enhanced plasma level has not yet been demonstrated in all the cases reported in humans. This experiment aimed at investigating the effect of fluoxetine on the kidney and more specifically in the inner medullary collecting duct (IMCD). Methods. ( 1) In vivo study: ( a) 10 rats were injected daily i. p. with 10 mg/kg fluoxetine doses. After 10 days, rats were sacrificed and blood and kidneys were collected. (b) Immunoblotting studies for AQP2 protein expression in the IMCD from injected rats and in IMCD tubules suspension from 10 normal rats incubated with 10(-7) M fluoxetine. ( 2) In vitro microperfusion study: The osmotic water permeability (P-f, mu m/s) was determined in normal rats IMCD (n = 6), isolated and perfused by the standard methods. Results. In vivo study: ( a) Injected rats with fluoxetine lost about 12% body weight; Na+ plasma level decreased from 139.3 +/- 0.78 mEq/1 to 134.9 +/- 0.5 mEq/1 ( p < 0.01) and K+ and ADH plasma levels remained unchanged. ( b) Immunoblotting densitometric analysis of the assays showed an increase in AQP2 protein abundance of about 40%, both in IMCDs from injected rats [ control period (cont) 99.6 +/- 5.2 versus Fx 145.6 +/- 16.9, p < 0.05] and in tubule suspension incubated with fluoxetine ( cont 100.0 +/- 3.5 versus 143.0 +/- 2.0, p < 0.01). In vitro microperfusion study fluoxetine increased Pf in the IMCD in the absence of ADH from the cont 7.24 +/- 2.07 to Fx 15.77 +/- 3.25 ( p < 0.01). Conclusion. After fluoxetine use, the weight and plasma Na+ level decreased, and the K+ and ADH plasma levels remained unchanged, whereas the AQP2 protein abundance and water absorption in the IMCD increased, leading us to conclude that the direct effect of fluoxetine in the IMCD could explain at least in part, the hyponatraemia found sometime after this drug use in humans.

Effect of the immunosuppressants on hepatocyte cells proliferation and apoptosis during liver regeneration after hepatectomy - molecular studies

The regeneration and remodeling of the transplanted liver is the result of hepatocyte proliferation and apoptosis (programmed cell death). The purpose of this study was to verify the influence of immunosuppressants on the expression levels of genes: IL-6 (regulator of hepatocyte proliferation), pro-apoptotic (Bak and Bax) and anti-apoptotic (Bcl-Xl and Bcl-2). 36 newborn suckling rats (age 5-7 days, weight 6-10 g) were divided into four groups: hepatectomy, hepatectomy plus methylprednisolone, hepatectomy plus CsA and hepatectomy plus Tac. The same experiments were performed in 24 weaning rats (age 21-23 days, weight 30-50 g). The animals were killed one day after the hepatectomy and the remnant livers were analyzed. The livers of all animals exhibited histological changes of liver regeneration. The immunosuppressants did not promote any alteration on IL-6 gene expression levels. Methylprednisolone and CsA increased the expression levels of Bak gene in newborn rats. However, methylprednisolone and Tac promoted increased expression levels of Bcl-2 in all groups. We hypothesize that these effects explain the efficacy of these drugs on the treatment of acute and chronic liver rejection as the expression of Bcl-2 in cholangiocytes is decreased as a consequence of bile duct lesions.

In vivo biological performance of a novel highly bioactive glass-ceramic (Biosilicate (R)): A biomechanical and histomorphometric study in rat tibial defects

This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicates (R)). Although a previous study demonstrated positive effects of Biosilicate (R) on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass (R) 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate group (R) (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate (R) and Bioglass (R) 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate (R) was superior to Bioglass (R) 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate (R) group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate (R) has good bone-forming and bone-bonding properties. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 978: 139-147, 2011.

The effect of oestrogen and alendronate therapies on postmenopausal bone loss around osseointegrated titanium implants

Objectives This study evaluated the influence of oestrogen deficiency and its therapies on bone tissue around osseointegrated implants. Methods Implants were placed in 66 female rats tibiae. The animals were assigned into five groups: control (CTL), sham, ovariectomy (OVX), oestrogen (EST), and alendronate (ALE). While CTL was sacrificed 60 days after implant placement, other groups were subjected to ovariectomy or sham surgery according to group and euthanized after 90 days. Blood and urine samples were collected at sacrifice day for osteocalcin (OCN) and deoxypyridinoline (DPD) quantification. Densitometry of femur and lumbar vertebrae was performed in order to evaluate rats` skeletal impairment. Non-decalcified sections were referred to fluorescent and light microscopy for analyses of mineral apposition rate (MAR), eroded and osteoclastic surfaces, bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO). Results Results from the OVX group showed significantly lower bone mineral density (BMD), BIC, BAFO, and MAR, while OCN, deoxipiridinoline, eroded surface and ostecoclastic surface were increased compared with the other groups of the study. ALE reduced OCN and DPD concentrations, MAR, osteoclastic and eroded surfaces, and no difference was in BIC and BAFO relative to SHAM. EST and CTL showed similar results to SHAM for measurements. Conclusions Oestrogen deficiency exerted a negative influence on bone tissue around implants, while oestrogen replacement therapy and alendronate were effective against its effects. Although alendronate therapy maintained the quantity of bone around implants, studies evaluating bone turnover kinetics are warranted. To cite this article:Giro G, Coelho PG, Pereira RMR, Jorgetti V, Marcantonio E Jr, Orrico SRP. The effect of oestrogen and alendronate therapies on postmenopausal bone loss around osseointegrated titanium implants.Clin. Oral Impl. Res. 22, 2011; 259-264.doi: 10.1111/j.1600-0501.2010.01989.x.