Interaction of adrenocorticotropin peptides with microheterogeneous systems - A fluorescence study

Adrenocorticotropin (ACM) and alpha-melanocyte stimulating hormone (alpha-MSH) are peptides which present many physiological effects related to pigmentation, motor and sexual behavior, learning and memory, analgesia, anti-inflammatory and antipyretic processes. The 13 amino acid residues of alpha-MSH are the same initial sequence of ACM and due to the presence of a tryptophan residue in position 9 of the peptide chain, fluorescence techniques could be used to investigate the conformational properties of the hormones in different environments and the mechanisms of interaction with biomimetic systems like sodium dodecyl sulphate (SDS) micelles, sodium dodecyl sulphate-poly(ethylene oxide) (SDS-PEO) aggregates and neutral polymeric micelles. In buffer solution, fluorescence parameters were typical of peptides containing tryptophan exposed to the aqueous medium and upon addition of surfactant and polymer molecules, the gradual change of those parameters demonstrated the interaction of the peptides with the microheterogeneous systems. From time-resolved experiments it was shown that the interaction proceeded with conformational changes in both peptides, and further information was obtained from quenching of Trp fluorescence by a family of N-alkylpyridinium ions, which possess affinity to the microheterogeneous systems dependent on the length of the alkyl chain. The quenching of Trp fluorescence was enhanced in the presence of charged micelles, compared to the buffer solution and the accessibility of the fluorophore to the quencher was dependent on the peptide and the alkylpyridinium: in ACTH(1-21) highest collisional constants were obtained using ethylpyridinium as quencher, indicating a location of the residue in the surface of the micelle, while in alpha-MSH the best quencher was hexylpyridinium, indicating insertion of the residue into the non-polar region of the micelles. The results had shown that the interaction between the peptides and the biomimetic systems where driven by combined electrostatic and hydrophobic effects: in ACTH(1-24) the electrostatic interaction between highly positively charged C-terminal and negatively charged surface of micelles; and aggregates predominates over hydrophobic interactions involving residues in the central region of the peptide; in alpha-MSH, which presents one residual positive charge, the hydrophobic interactions are relevant to position the Trp residue in the non-polar region of the microheterogeneous systems. (C) 2008 Elsevier B.V. All rights reserved.

Production of fibrolytic enzymes by Aspergillus japonicus C03 using agro-industrial residues with potential application as additives in animal feed

Solid-state fermentation obtained from different and low-cost carbon sources was evaluated to endocellulases and endoxylanases production by Aspergillus japonicus C03. Regarding the enzymatic production the highest levels were observed at 30 degrees C, using soy bran added to crushed corncob or wheat bran added to sugarcane bagasse, humidified with salt solutions, and incubated for 3 days (xylanase) or 6 days (cellulase) with 70% relative humidity. Peptone improved the xylanase and cellulase activities in 12 and 29%, respectively. The optimum temperature corresponded to 60 degrees C and 50-55 degrees C for xylanase and cellulase, respectively, both having 4.0 as optimum pH. Xylanase was fully stable up to 40 degrees C, which is close to the rumen temperature. The enzymes were stable in pH 4.0-7.0. Cu(++) and Mn(++) increased xylanase and cellulase activities by 10 and 64%, respectively. A. japonicus C03 xylanase was greatly stable in goat rumen fluid for 4 h during in vivo and in vitro experiments.

The interaction between N-category and N-ratio as a new tool to improve lymph node metastasis staging in gastric cancer: Results of a single cancer center in Brazil

Background: Depth of tumor invasion (T-category) and the number of metastatic lymph nodes (N-category) are the most important prognostic factors in patients with gastric cancer. Recently, the ratio between metastatic and dissected lymph nodes (N-ratio) has been established as one. The aim of this study is to evaluate the impact of N-ratio and its interaction with N-category as a prognostic factor in gastric cancer. Methods: This was a retrospective study in which we reviewed clinical and pathological data of 165 patients who had undergone curative surgery at our institution through a 9-year period. The exclusion criteria included metastases, gastric stump tumors and gastrectomy with less than 15 lymph nodes dissected. Results: The median age of the patients was 63 years and most of them were male. Total gastrectomy was the most common procedure and 92.1% of the patients had a D2-lymphadenectomy. Their 5-year overall survival was 57.7%. T-category, N-category, extended gastrectomy, and N-ratio were prognostic factors in overall and disease-free survival in accordance with univariate analysis. In accordance with TNM staging, N1 patients who have had NR1 had 5-year survival in 75.5% whereas in the NR2 group only 33% of the cases had 5-year survival. In the multivariate analysis, the interaction between N-category and N-ratio was an independent prognostic factor. Conclusion: Our findings confirmed the role of N-ratio as prognostic factor of survival in patients with gastric cancer surgically treated with at least 15 lymph nodes dissected. The relationship between N-category and N-ratio is a better predictor than lymph node metastasis staging. (C) 2010 Elsevier Ltd. All rights reserved.

Online monitoring of pulse pressure variation to guide fluid therapy after cardiac surgery

BACKGROUND: The arterial pulse pressure variation induced by mechanical ventilation (Delta PP) has been shown to be a predictor of fluid responsiveness. Until now, Delta PP has had to be calculated offline (from a computer recording or a paper printing of the arterial pressure curve), or to be derived from specific cardiac output monitors, limiting the widespread use of this parameter. Recently, a method has been developed for the automatic calculation and real-time monitoring of Delta PP using standard bedside monitors. Whether this method is to predict reliable predictor of fluid responsiveness remains to be determined. METHODS: We conducted a prospective clinical study in 59 mechanically ventilated patients in the postoperative period of cardiac surgery. Patients studied were considered at low risk for complications related to fluid administration (pulmonary artery occlusion pressure <20 mm Hg, left ventricular ejection fraction >= 40%). All patients were instrumented with an arterial line and a pulmonary artery catheter. Cardiac filling pressures and cardiac output were measured before and after intravascular fluid administration (20 mL/kg of lactated Ringer`s solution over 20 min), whereas Delta PP was automatically calculated and continuously monitored. RESULTS: Fluid administration increased cardiac output by at least 15% in 39 patients (66% = responders). Before fluid administration, responders and nonresponders were comparable with regard to right atrial and pulmonary artery occlusion pressures. In contrast, Delta PP was significantly greater in responders than in nonresponders, (17% +/- 3% vs 9% +/- 2%, P < 0.001). The Delta PP cut-off value of 12% allowed identification of responders with a sensitivity of 97% and a specificity of 95%. CONCLUSION: Automatic real-time monitoring of Delta PP is possible using a standard bedside rnonitor and was found to be a reliable method to predict fluid responsiveness after cardiac surgery. Additional studies are needed to determine if this technique can be used to avoid the complications of fluid administration in high-risk patients.

Arterial pulse pressure variation predicting fluid responsiveness in critically ill patients (Retracted article. See vol. 31, pg. 542, 2009)

In critically ill patients, it is important to predict which patients will have their systemic blood flow increased in response to volume expansion to avoid undesired hypovolemia and fluid overloading. Static parameters such as the central venous pressure, the pulmonary arterial occlusion pressure, and the left ventricular end-diastolic dimension cannot accurately discriminate between responders and nonresponders to a fluid challenge. In this regard, respiratory-induced changes in arterial pulse pressure have been demonstrated to accurately predict preload responsiveness in mechanically ventilated patients. Some experimental and clinical studies confirm the usefulness of arterial pulse pressure as a useful tool to guide fluid therapy in critically ill patients.

Fluid Resuscitation With Isotonic or Hypertonic Saline Solution Avoids Intraneural Calcium Influx After Traumatic Brain Injury Associated With Hemorrhagic Shock

Background: Calcium is one of the triggers involved in ischemic neuronal death. Because hypotension is a strong predictor of outcome in traumatic brain injury (TBI), we tested the hypothesis that early fluid resuscitation blunts calcium influx in hemorrhagic shock associated to TBI. Methods: Fifteen ketamine-halothane anesthetized mongrel dogs (18.7 kg +/- 1.4 kg) underwent unilateral cryogenic brain injury. Blood was shed in 5 minutes to a target mean arterial pressure of 40 mm Hg to 45 mm Hg and maintained at these levels for 20 minutes (shed blood volume = 26 mL/kg +/- 7 mL/kg). Animals were then randomized into three groups: CT (controls, no fluid resuscitation), HS (7.5% NaCl, 4 mL/kg, in 5 minutes), and LR (lactate Ringer`s, 33 mL/kg, in 15 minutes). Twenty minutes later, a craniotomy was performed and cerebral biopsies were obtained next to the lesion (""clinical penumbra"") and from the corresponding contralateral side (""lesion`s mirror"") to determine intracellular calcium by fluorescence signals of Fura-2-loaded cells. Results: Controls remained hypotensive and in a low-flow state, whereas fluid resuscitation improved hemodynamic profile. There was a significant increase in intracellular calcium in the injured hemisphere in CT (1035 nM +/- 782 nM), compared with both HS (457 nM +/- 149 nM, p = 0.028) and LR (392 nM +/- 178 nM, p = 0.017), with no differences between HS and LR (p = 0.38). Intracellular calcium at the contralateral, uninjured hemisphere was 438 nM +/- 192 nM in CT, 510 nM +/- 196 nM in HS, and 311 nM +/- 51 nM in LR, with no significant differences between them. Conclusion: Both small volume hypertonic saline and large volume lactated Ringer`s blunts calcium influx in early stages of TBI associated to hemorrhagic shock. No fluid resuscitation strategy promotes calcium influx and further neural damage.

Effects of chronic L-NAME treatment lung tissue mechanics, eosinophilic and extracellular matrix responses induced by chronic pulmonary inflammation

The importance of lung tissue in asthma pathophysiology has been recently recognized. Although nitric oxide mediates smooth muscle tonus control in airways, its effects on lung tissue responsiveness have not been investigated previously. We hypothesized that chronic nitric oxide synthase (NOS) inhibition by N-omega-nitro-L-arginine methyl ester (L-NAME) may modulate lung tissue mechanics and eosinophil and extracellular matrix remodeling in guinea pigs with chronic pulmonary inflammation. Animals were submitted to seven saline or ovalbumin exposures with increasing doses (1 similar to 5 mg/ml for 4 wk) and treated or not with L-NAME in drinking water. After the seventh inhalation (72 h), animals were anesthetized and exsanguinated, and oscillatory mechanics of lung tissue strips were performed in baseline condition and after ovalbumin challenge (0.1%). Using morphometry, we assessed the density of eosinophils, neuronal NOS (nNOS)- and inducible NOS (iNOS)-positive distal lung cells, smooth muscle cells, as well as collagen and elastic fibers in lung tissue. Ovalbumin-exposed animals had an increase in baseline and maximal tissue resistance and elastance, eosinophil density, nNOS- and iNOS-positive cells, the amount of collagen and elastic fibers, and isoprostane-8-PGF(2 alpha) expression in the alveolar septa compared with controls (P < 0.05). L-NAME treatment in ovalbumin-exposed animals attenuated lung tissue mechanical responses (P < 0.01), nNOS- and iNOS-positive cells, elastic fiber content (P < 0.001), and isoprostane-8-PGF(2 alpha) in the alveolar septa (P < 0.001). However, this treatment did not affect the total number of eosinophils and collagen deposition. These data suggest that NO contributes to distal lung parenchyma constriction and to elastic fiber deposition in this model. One possibility may be related to the effects of NO activating the oxidative stress pathway.

Effects of Fluid Resuscitation on Cardiovascular Performance After Posttraumatic Pneumonectomy

Background: Several factors have been implicated in the high-mortality rate of posttraumatic pneumonectomy. In this study, we evaluated the hemodynamic and echocardiographic changes induced by pneumonectomy and fluid resuscitation after hemorrhagic shock. Methods: Fourteen dogs were bled to a target mean arterial pressure of 40 mmHg. The animals were assigned to two groups: control (no fluid resuscitation) and lactated Ringer`s (3 x shed blood volume). The left pulmonary hilum was cross clamped, and the animals were observed for 60 minutes. Systemic hemodynamics was evaluated using Swan-Ganz, arterial catheter, and ultrasonic flow probe. Systemic O(2)-derived variables were calculated. Ejection fraction was determined by two-dimensional echocardiography. Results: Fluid resuscitation improved the mean arterial pressure and systemic oxygen delivery. After pneumonectomy, no significant increase in right ventricular pressure was observed in the LR group. No signs of major ventricular dilation or changes in arterial oxygenation were observed. Conclusion: Our data suggest that pneumonectomy is not associated with early pulmonary hypertension; gentle fluid resuscitation improves cardiovascular performance and is not associated with an increase in right ventricular pressure.

Metabolic syndrome determinants in an urban population from Brazil: Social class and gender-specific interaction

Introduction: The metabolic syndrome (MS) is characterized by multiple cardiovascular risk factors such as central obesity, arterial hypertension, dislipidemia and hyperinsulinemia and is associated with a higher incidence of cardiovascular events and mortality. The aim of the present work is to describe the prevalence of MS in an urban population from a highly admixed developing country and to characterize the different correlations between this diagnosis, cardiovascular risk factors and demographic variables distributed in this population. Materials and methods: A cross-sectional study of risk factors for cardiovascular diseases was performed in the urban population of Vitoria, Brazil (n= 1507). Major cardiovascular risk factors such as smoking habits, alcohol intake, amount of physical activity, diabetes and hypertension were inquired. Blood biochemical assays were performed by standard techniques in 12 h fasting blood sample and Metabolic Syndrome (MS) was characterizes following the ATP III criteria. Results: The analysis of 1507 individuals showed a 25.43% general prevalence of MS without any significant difference between sexes, but a clear relation of the prevalence with progressing age (p=<0.0001). Even though both sexes showed similar prevalence rates, distribution of risk factors that defined MS was different between men and women, with the prevalence of hypertension, fasting hyperglycemia and hypertriglyceridemia being higher in men. Race was not an important risk factor for MS in this population as opposed to social economic class that was highly associated with the risk of MS in women as their social class was lower, but not in men. Conclusion: This cross-sectional study from a large urban population in Brazil showed a high general prevalence of MS (25.4%), which is increased as the population becomes older (especially in women) and poorer. Although prevalence was very similar in both genders, the frequency of components defining the syndrome varied greatly amongst them. In particular, a significant interaction between gender and social class was observed and may shed light in our understanding of the complex interplay between demographic and biological risk factors for metabolic syndrome. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

Influence of the interaction between nodal fibroblast and breast cancer cells on gene expression

Our aim was to evaluate the interaction between breast cancer cells and nodal fibroblasts, by means of their gene expression profile. Fibroblast primary cultures were established from negative and positive lymph nodes from breast cancer patients and a similar gene expression pattern was identified, following cell culture. Fibroblasts and breast cancer cells (MDA-MB231, MDA-MB435, and MCF7) were cultured alone or co-cultured separated by a porous membrane (which allows passage of soluble factors) for comparison. Each breast cancer lineage exerted a particular effect on fibroblasts viability and transcriptional profile. However, fibroblasts from positive and negative nodes had a parallel transcriptional behavior when co-cultured with a specific breast cancer cell line. The effects of nodal fibroblasts on breast cancer cells were also investigated. MDA MB-231 cells viability and migration were enhanced by the presence of fibroblasts and accordingly, MDA-MB435 and MCF7 cells viability followed a similar pattern. MDA-MB231 gene expression profile, as evaluated by cDNA microarray, was influenced by the fibroblasts presence, and HNMT, COMT, FN3K, and SOD2 were confirmed downregulated in MDA-MB231 co-cultured cells with fibroblasts from both negative and positive nodes, in a new series of RT-PCR assays. In summary, transcriptional changes induced in breast cancer cells by fibroblasts from positive as well as negative nodes are very much alike in a specific lineage. However, fibroblasts effects are distinct in each one of the breast cancer lineages, suggesting that the inter-relationships between stromal and malignant cells are dependent on the intrinsic subtype of the tumor.

Magnetic characterization by SQUID and FMR of a biocompatible ferrofluid based on Fe(3)O(4)

Biocompatible superparamagnetic iron oxide nanoparticles of magnetite coated with dextran were magnetically characterized using the techniques of SQUID (superconducting quantum interference device) magnetometry and ferromagnetic resonance (FMR). The SQUID magnetometry characterization was performed by isothermal measurements under applied magnetic field using the methods of zero-field-cooling (ZFC) and field-cooling (FC). The magnetic behavior of the nanoparticles indicated their superparamagnetic nature and it was assumed that they consisted exclusively of monodomains. The transition to a blocked state was observed at the temperature T(B) = (43 +/- 1) K for frozen ferrofluid and at (52 +/- 1) K for the lyophilized ferrofluid samples. The FMR analysis showed that the derivative peak-to-peak linewidth (Delta H(PP)), gyromagnetic factor (g), number of spins (N(S)), and spin-spin relaxation time (T(2)) were strongly dependent on both temperature and super-exchange interaction. This information is important for possible nanotechnological applications, mainly those which are strongly dependent on the magnetic parameters.

Enolase from Paracoccidioides brasiliensis: isolation and identification as a fibronectin-binding protein

Paracoccidioides brasiliensis yeast cells can enter mammalian cells and may manipulate the host cell environment to favour their own growth and survival. Moreover, fibronectin and several other host extracellular matrix proteins are recognized by various components of the yeast cell extracts. The present study was designed to isolate and characterize a fibronectin-binding protein from P. brasiliensis. We also compared P. brasiliensis strain 18, tested before (Pb18a) and after (Pb18b) animal passage, in relation to its adhesion and invasion processes. Extracts from both samples, when cultured on blood agar solid medium, showed higher levels of protein expression than when the same samples were cultured on Fava-Netto solid medium, as demonstrated by two-dimensional electrophoresis and SDS-PAGE. Also, both Pb18a and Pb18b exhibited stronger adhesion to A549 epithelial cells when cultured on blood agar medium than when cultured on Fava-Netto medium. Ligand affinity binding assays revealed a protein of 54 kDa and pl 5.6 in P. brasiliensis cell-free extracts with the properties of a fibronectin-binding adhesin, which was characterized by tryptic digestion and mass spectroscopy as a homologue of enolase from P. brasiliensis. Antibody raised against this 54 kDa protein abolished 80 % of P. brasiliensis adhesion to A549 epithelial cells. Our results demonstrate that P. brasiliensis produces a fibronectin-binding adhesin, irrespective of the culture medium, and that this activity can be inhibited by a specific antibody and is involved in the adhesion of the fungus to pulmonary epithelial cells.

Endemic and opportunistic infections in Brazilian solid organ transplant recipients

OBJECTIVE To evaluate the frequency and clinical features of endemic and other opportunistic infections in liver or kidney transplant recipients in four transplant centres in different geographical areas of Brazil. METHODS Retrospective analysis of medical and laboratory records of four transplant centres on endemic and other opportunistic infections in liver or kidney transplant recipients. Analyses were performed with spss statistical software. RESULTS From 2001 to 2006, 1046 kidney and 708 liver transplants were registered in all centres. The average age was 42 years. Among 82 (4.7%) cases with infections, the most frequent was tuberculosis (2.0%), followed by systemic protozoal infections (0.7%), toxoplasmosis (0.4%) and visceral leishmaniasis (0.3%). Systemic fungal infections occurred in 0.6%, of which 0.4% were cryptococcosis and 0.2% were histoplasmosis. Dengue was the only systemic viral infection and was registered in two cases (0.1%), of which one was classified as the classic form and the other as dengue haemorrhagic fever. Nocardiosis was described in one case (0.05%). The infectious agents most frequently associated with diarrhoea were Blastocystis sp., Schistosoma mansoni and Strongyloides stercoralis. CONCLUSIONS Opportunistic Infections in transplant patients have a wide spectrum and may vary from asymptomatic to severe infections with high mortality. A better understanding of the epidemiology of endemic pathogens and clinical manifestations can contribute to the establishment of an early diagnosis as well as correct treatment aimed at decreasing morbidity and mortality.

Solid pseudopapillary neoplasm of the pancreas: distinct patterns of onset, diagnosis, and prognosis for male versus female patients

Background. Solid pseudopapillary neoplasm of the pancreas is a distinctive pancreatic neoplasm with low metastatic potential. This study examines clinical differences and prognosis between male and female Patients. Methods. The medical records of 34 consecutive patients with pancreatic solid pseudopapillaly neoplasms between 1990 and 2006 were reviewed. Whenever feasible, organ-preserving operation was performed. Statistical analysis was performed using chi-square and Student t test. Results. There were 27 women (79%) and seven men (21%) with median age of 23 years. Mean diameter of the tumor was 7 cm. Tumor size tended to be smaller in patients treated in more recent years. Conservative surgery was possible in I I patients including spleen-preserving distal pancreatectomy in 3, central pancreatectomy in 5, and enucleation in 3 patients. Median hospital stay was 11 days, morbidity rate was 62%, including 17 patients with grade A pancreatic fistula, and there was no operative mortality. Mean follow-up time was 84 months. Tumor recurred in 2 patients (6%). Overall late morbidity rate was 12%. At the time of diagnosis, age was ((x) over bar +/- SD) higher among male patients (25 +/- 2 years vs 37 +/- 7 years, P < .05) with no difference in tumor size. The neoplasms were more aggressive in male Patients; therefore, conservative surgery was less likely. There was no correlation between tumor aggressiveness and age of the patient or size of tumor. Conclusion. This is the first single center study to demonstrate that solid pseudopapillary neoplasms in male patients have distinct Patterns Of onset and aggressiveness when compared with female patients. Although valid prognostic criteria are still lacking, it appears that male patients may be best treated by more radical operation and should be observed more closely during follow-up.

Changes in Amniotic Fluid Index after Maternal Oral Hydration in Pregnancies with Fetal Gastroschisis: Initial Observations

Objective: To evaluate the effect of maternal oral hydration on amniotic fluid index (AFI) in pregnancies with fetal gastroschisis. Methods: AFI was evaluated at 24-hour intervals, during 4 consecutive days, under a continuous maternal oral water hydration regimen, in singleton pregnancies with isolated fetal gastroschisis. Results: Nine pregnancies were examined at a mean gestational age of 31.6 weeks (+/-1.4) and mean maternal daily oral water intake was 3,437 (+/-810) ml. Mean AFI on days 0-3 were 13.2 (+/-2.9), 14.8 (+/-3.3), 14.5 (+/-3.1) and 14.8 (+/-2.6), respectively. AFI on day 0 was significantly lower compared to all the other 3 days (p = 0.01 and 0.02). Significant correlation was found in relative difference in AFI between day 0 and day 1 and gestational age (r = -0.67, p = 0.05) and the amount of water intake in the previous 24 h (r = 0.76, p = 0.02). Conclusion: Maternal oral water hydration significantly increases AFI in pregnancies with isolated fetal gastroschisis. Copyright (C) 2010 S. Karger AG, Basel