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.

Meta-analysis of infrapopliteal angioplasty for chronic critical limb ischemia

Background: Percutaneous transluminal angioplasty has been used with increasing frequency in the treatment of infrainguinal arterial occlusive disease. This meta-analysis aimed to assess the middle-term outcomes after crural angioplasty in patients with chronic critical limb ischemia and compare results with a meta-analysis of popliteal-to-distal vein bypass graft. Methods: Data were retrieved from 30 articles published from 1990 through 2006 (63% of articles published between 2000 and 2006). All studies used survival analysis, reported a 12-month cumulative rate of patency or limb salvage, and included at least 15 infrapopliteal angioplasties. The outcome measures were immediate technical success, primary and secondary patency, limb salvage, and patient survival. Data from life-tables, survival curves, and texts were used. Results. The pooled estimate of success was 89.0% +/- 2.2% for immediate technical result. Results at 1 and 36 months were 77.4% +/- 4.1% and 48.6% +/- 8.0% for primary patency, 83.3% +/- 1.4% and 62.9% +/- 11.0% for secondary patency, 93.4% +/- 2.3% and 82.4% +/- 3.4% for limb salvage, and 98.3% +/- 0.7% and 68.4% +/- 5.5% for patient survival, respectively. Studies with >75% of the limbs with tissue loss fared worse than their respective comparative subgroup for technical success and patency but not for limb salvage or survival. No publication bias was detected. Conclusion: The technical success and subsequent durability of crural angioplasty are limited compared with bypass surgery, but the clinical benefit is acceptable because limb salvage rates are equivalent to bypass surgery. Further studies are necessary to determine the proper role of infrapopliteal angioplasty.

Preferential use of nonreversed vein grafts in above-knee femoropopliteal bypasses for critical ischemia: Midterm outcome

We evaluated nonreversed vein grafts in above-knee bypasses for chronic critical limb ischemia in a retrospective study with intention-to-treat analysis in patients who underwent above-knee bypass grafting. During a 4-year period, 51 patients (men, 32; women, 19; mean age 66 years) with 53 critically ischemic lower extremities underwent above-knee femoropopliteal bypass grafting. The follow-up evaluation consisted of clinical examination, assessment of the ankle- brachial systolic blood pressure index, and, whenever necessary, duplex scanning. Three ( 5.7%) deaths occurred within 30 days, two from myocardial infarction and one from an undetermined cause. The 2-year cumulative success rate was 82.5 +/- 9.6% for primary patency, 84.6 +/- 8.9% for secondary patency, 90.1 +/- 7.3% for tertiary patency, 86.9 +/- 7.6% for limb salvage, 77.7 +/- 8.4% for survival, 68.0 +/- 11.1% for composite patency, and 68.4 +/- 9.3% for amputation- free survival; the corresponding estimates for vein grafts alone were 86.6 +/- 9.2%, 88.9 +/- 8.6%, 89.0 +/- 8.5%, 88.1 +/- 8.1%, 81.1 +/- 9.1, 76.8 +/- 11.1%, and 72.6 +/- 10.2%. Three prosthetic grafts failed and were replaced with an arm vein graft. Nonreversed vein bypass grafts in above- knee revascularization of critically ischemic limbs are justified.

Neutrophils recruitment during sepsis: Critical points and crossroads

The mechanisms that initiate an inflammatory systemic response to a bacterial infection lead to a high mortality and constitute the first cause of death in Critical Care Units (ICU`s). Sepsis is a poorly understood disease and despite life support techniques and the administration of antibiotics, not much more can be done to improve its diagnosis and treatment. The present article has as main objective to discuss the role of neutrophils recruitment in sepsis, dissecting the molecular mechanisms implicated in this complex process and its importance to the pathogenesis of this outstanding cause of death.

Time- and Fluid-Sensitive Resuscitation for Hemodynamic Support of Children in Septic Shock Barriers to the Implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support Guidelines in a Pediatric Intensive Care Unit in a Developing World

Objectives: To analyze mortality rates of children with severe sepsis and septic shock in relation to time-sensitive fluid resuscitation and treatments received and to define barriers to the implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support guidelines in a pediatric intensive care unit in a developing country. Methods: Retrospective chart review and prospective analysis of septic shock treatment in a pediatric intensive care unit of a tertiary care teaching hospital. Ninety patients with severe sepsis or septic shock admitted between July 2002 and June 2003 were included in this study. Results: Of the 90 patients, 83% had septic shock and 17% had severe sepsis; 80 patients had preexisting severe chronic diseases. Patients with septic shock who received less than a 20-mL/kg dose of resuscitation fluid in the first hour of treatment had a mortality rate of 73%, whereas patients who received more than a 40-mL/kg dose in the first hour of treatment had a mortality rate of 33% (P < 0.05.) Patients treated less than 30 minutes after diagnosis of severe sepsis and septic shock had a significantly lower mortality rate (40%) than patients treated more than 60 Minutes after diagnosis (P < 0.05). Controlling for the risk of mortality, early fluid resuscitation was associated with a 3-fold reduction in the odds of death (odds ratio, 0.33; 95% confidence interval, 0.13-0.85). The most important barriers to achieve adequate severe sepsis and septic shock treatment were lack of adequate vascular access, lack of recognition of early shock, shortage of health care providers, and nonuse of goals and treatment protocols. Conclusions: The mortality rate was higher for children older than years, for those who received less than 40 mL/kg in the first hour, and for those whose treatment was not initiated in the first 30 Minutes after the diagnosis of septic shock. The acknowledgment of existing barriers to a timely fluid administration and the establishment of objectives to overcome these barriers may lead to a more successful implementation of the American College of Critical Care Medicine guidelines and reduced mortality rates for children with septic shock in the developing world.

Pleural fluid: Are temperature and storage time critical preanalytical error factors in biochemical analyses?

Background: Biochemical analysis of fluid is the primary laboratory approach hi pleural effusion diagnosis. Standardization of the steps between collection and laboratorial analyses are fundamental to maintain the quality of the results. We evaluated the influence of temperature and storage time on sample stability. Methods: Pleural fluid from 30 patients was submitted to analyses of proteins, albumin, lactic dehydrogenase (LDH), cholesterol, triglycerides, and glucose. Aliquots were stored at 21 degrees, 4 degrees, and-20 degrees C, and concentrations were determined after 1, 2, 3, 4, 7, and 14 days. LDH isoenzymes were quantified in 7 random samples. Results: Due to the instability of isoenzymes 4 and 5, a decrease in LDH was observed in the first 24 h in samples maintained at -20 degrees C and after 2 days when maintained at 4 degrees C. Aside from glucose, all parameters were stable for up to at least day 4 when stored at room temperature or 4 degrees C. Conclusions: Temperature and storage time are potential preanalytical errors in pleural fluid analyses, mainly if we consider the instability of glucose and LDH. The ideal procedure is to execute all the tests immediately after collection. However, most of the tests can be done in refrigerated sample;, excepting LDH analysis. (C) 2010 Elsevier B.V. All rights reserved.

Photodynamic therapy for acne vulgaris: A critical review from basics to clinical practice Part II. Understanding parameters for acne treatment with photodynamic therapy

Photodynamic therapy requires a photosensitizer, oxygen, and activating light. For acne, pilosebaceous units are ""target"" structures. Porphyrins are synthesized in vivo from 5-aminolevulinic acid (ALA), particularly in pilosebaceous units. Different photosensitizers and drug delivery methods have been reported for acne treatment. There are a variety of porphyrin precursors with different pharmacokinetic properties. Among them, ALA and methyl-ester of ALA (MAT.) are available for possible off-label treatment of acne vulgaris. In addition, various light sources, light dosimetry, drug incubation time, and pre- and posttreatment care also change efficacy and side effects. None of these variables has been optimized for acne treatment, but a number of clinical trials provide helpful guidance. In this paper, we critically analyze clinical trials, case reports, and series of cases published through 2009. (J Am Acad Dermatol 2010;63:195-211.)

Extending the Phenotype of Monosomy 1p36 Syndrome and Mapping of a Critical Region for Obesity and Hyperphagia

Rearrangements of 1p36 are the most frequently detected abnormalities in diagnostic testing for chromosomal cryptic imbalances and include variably sized simple terminal deletions, derivative chromosomes, interstitial deletions, and complex rearrangements. These rearrangements result in the specific pattern of malformation and neurodevelopmental disabilities that characterizes monosomy 1p36 syndrome. Thus far, no individual gene within this region has been conclusively determined to be causative of any component of the phenotype. Nor is it known if the rearrangements convey phenotypes via a haploinsufficiency mechanism or through a position effect. We have used multiplex ligation-dependent probe amplification to screen for deletions of 1p36 in a group of 154 hyperphagic and overweight/obese, PWS negative individuals, and in a separate group of 83 patients initially sent to investigate a variety of other conditions. The strategy allowed the identification and delineation of rearrangements in nine subjects with a wide spectrum of clinical presentations. Our work reinforces the association of monosomy 1p36 and obesity and hyperphagia, and further suggests that these features may be associated with non-classical manifestations of this disorder in addition to a submicroscopic deletion of similar to 2-3 Mb in size. Multiplex ligation probe amplification using the monosomy 1p36 syndrome-specific kit coupled to the subtelomeric kit is an effective approach to identify and delineate rearrangements at 1p36. (C) 2009 Wiley-Liss, Inc.

Nonoperative Approaches to Rectal Cancer: A Critical Evaluation

A neoadjuvant multimodality approach with chemoradiation therapy (CRT) is the preferred treatment strategy for most distal rectal cancers. Significant downstaging and complete pathologic response may develop after this strategy, and there is still controversy regarding the management of these patients. In this setting, a nonoperative approach has been suggested in select patients with complete clinical response after thorough clinical, endoscopic, and radiologic assessment. However, the assessment of these patients is not straightforward and remains complex. Available data regarding this approach are limited to a single institution`s experience from retrospective analyses. Standardization of the assessment of tumor response and the development of radiological/molecular tools may clarify the role of no immediate surgery in patients with complete clinical response after neoadjuvant CRT. Advances in radiation and medical oncology could potentially lead to significant improvements in complete tumor regression rates, leading to an increase in importance of a minimally invasive approach in patients with rectal cancer. Semin Radiat Oncol 21:234-239 (C) 2011 Elsevier Inc. All rights reserved.

Safety Profile of Trocar and Insufflation Needle Access Systems in Laparoscopic Surgery

BACKGROUND: The most common laparoscopic complications are associated with trocar insertion. The purpose of this study was to develop an objective method of evaluating the safety profile of various access devices used in laparoscopic surgery. STUDY DESIGN: In 20 swine, 6 bladed and 2 needle access devices were evaluated. A force profile was determined by measuring the force required to drive the trocar or needle through the fascia and into the peritoneum, at 0 and 10 mmHg. The amount Of tissue deformation, the length of blade exposed, and the duration of exposure were measured using a high-speed digital imaging system. RESULTS: The needle system without the sheath required the least driving force and had the most favorable force profile. In contrast, the bladed, nonretractable trocar system required a higher driving force and a rapid loss of resistance. Insertion under a pneumoperitoneum did not significantly alter the force profile of the various access devices except for the amount of tissue deformation. With the bladed system, the blade itself was exposed for an average of 0.5 to 1.0 seconds for a distance of 4.5 to 5.0 cm. In comparison, the needle system was exposed for 0.2 seconds for a distance of 1.8 cm. CONCLUSIONS: We developed a reproducible method of measuring the forces required to place the access systems, their pattern of resistance loss, and the characteristics of the blade exposure. These parameters may provide an adjunctive and objective measurement of safety, allowing for more direct comparison between various trocar designs. (J Am Coll Surg 2009;209:222-232. (C) 2009 by the American College of Surgeons)

Performance of patients with refractory obsessive-compulsive disorder in the Frontal Systems Behavior Scale

Objective: To compare the performance of patients with obsessive-compulsive disorder (OCD) refractory to conventional treatments to healthy controls according to the Frontal Systems Behaviour Scale (FrSBe), comparing the scale scores within each group (Self or Family) and correlating FrSBe with Y-BOCS, DY-BOCS, tic disorder and age of first symptoms. Method: Twenty OCD patients and 20 healthy controls were assessed using the FrSBe, a scale designed to evaluate frontal syndromes. Results: The patients had higher scores when compared with the control group (p value .001) in terms of total score on the scale for both profile forms (Self and Family). In addition, there was a significant difference between the scores reported by the patients and their respective relatives. However, no correlation was observed between the scale and the other variables. Conclusions: The scale was able to clearly differentiate patients with OCD from healthy controls. This finding suggests that the FrSBe can be used not only in neurologic patients but also in psychiatric cases such as refractory OCD.

Comparison of three systems of classification in predicting the outcome of diabetic foot ulcers in a Brazilian population

Objective: The aim was to compare there ulcer classification systems as predictors of the outcome of diabetic foot ulcers; the Wagner, the University of Texas (UT) and the size (area, depth), sepsis, arteriopathy, denervation system (S(AD)SAD) systems in specialist clinic in Brazil. Methods: Ulcer area, depth, appearance, infection and associated ischaemia and neuropathy were recorded in a consecutive series of 94 subjects. A novel score, the S(AD)SAD score, was derived from the sum of individual items of the S(AD)SAD system, and was evaluated. Follow-up was for at least 6 months. The primary outcome measure was the incidence of healing. Results: Mean age was 57.6 years; 57 (60.6%) were made. Forty-eight ulcers (51.1%) healed without surgery; 11 (12.2%) subjects underwent minor amputation. Significant differences in terms of healing were observed for depth (P = 0.002), infection (P = 0.006) and denervation (P = 0.002) using the S(AD)SAD system, for UT grade (P = 0.002) and stage (P = 0.032) and for Wagner grades (P = 0.002). Ulcers with an S(AD)SAD score of <= 9 (total possible 15) were 7.6 times more likely to heal than scores >= 10 (P < 0.001). Conclusions: All three systems predicted ulcer outcome. The S(AD)SAD score of ulcer severity could represent a useful addition to routine clinical practice. The association between outcome and ulcer depth confirms earlier reports. The association with infection was stronger than that reported from the centres in Europe or North America. The very strong association with neuropathy has only previously been observed in Tanzania. Studies designed to compare the outcome in different countries should adopt systems of classification, which are valid for the populations studied.

Supporting content-based image retrieval and computer-aided diagnosis systems with association rule-based techniques

In this work, we take advantage of association rule mining to support two types of medical systems: the Content-based Image Retrieval (CBIR) systems and the Computer-Aided Diagnosis (CAD) systems. For content-based retrieval, association rules are employed to reduce the dimensionality of the feature vectors that represent the images and to improve the precision of the similarity queries. We refer to the association rule-based method to improve CBIR systems proposed here as Feature selection through Association Rules (FAR). To improve CAD systems, we propose the Image Diagnosis Enhancement through Association rules (IDEA) method. Association rules are employed to suggest a second opinion to the radiologist or a preliminary diagnosis of a new image. A second opinion automatically obtained can either accelerate the process of diagnosing or to strengthen a hypothesis, increasing the probability of a prescribed treatment be successful. Two new algorithms are proposed to support the IDEA method: to pre-process low-level features and to propose a preliminary diagnosis based on association rules. We performed several experiments to validate the proposed methods. The results indicate that association rules can be successfully applied to improve CBIR and CAD systems, empowering the arsenal of techniques to support medical image analysis in medical systems. (C) 2009 Elsevier B.V. All rights reserved.

Regulation of chemokine receptor by Toll-like receptor 2 is critical to neutrophil migration and resistance to polymicrobial sepsis

Patients with sepsis have a marked defect in neutrophil migration. Here we identify a key role of Toll-like receptor 2 (TLR2) in the regulation of neutrophil migration and resistance during polymicrobial sepsis. We found that the expression of the chemokine receptor CXCR2 was dramatically down-regulated in circulating neutrophils from WT mice with severe sepsis, which correlates with reduced chemotaxis to CXCL2 in vitro and impaired migration into an infectious focus in vivo. TLR2 deficiency prevented the down-regulation of CXCR2 and failure of neutrophil migration. Moreover, TLR2(-/-) mice exhibited higher bacterial clearance, lower serum inflammatory cytokines, and improved survival rate during severe sepsis compared with WT mice. In vitro, the TLR2 agonist lipoteichoic acid (LTA) down-regulated CXCR2 expression and markedly inhibited the neutrophil chemotaxis and actin polymerization induced by CXCL2. Moreover, neutrophils activated ex vivo by LTA and adoptively transferred into naive WT recipient mice displayed a significantly reduced competence to migrate toward thioglycolate-induced peritonitis. Finally, LTA enhanced the expression of G protein-coupled receptor kinases 2 (GRK2) in neutrophils; increased expression of GRK2 was seen in blood neutrophils from WT mice, but not TLR2(-/-) mice, with severe sepsis. Our findings identify an unexpected detrimental role of TLR2 in polymicrobial sepsis and suggest that inhibition of TLR2 signaling may improve survival from sepsis.