Adaptive filtering of ECG interference on surface EEnGs based on signal averaging

An external electroenterogram (EEnG) is the recording of the small bowel myoelectrical signal using contact electrodes placed on the abdominal surface. It is a weak signal affected by possible movements and by the interferences of respiration and, principally, of the cardiac signal. In this paper an adaptive filtering technique was proposed to identify and subsequently cancel ECG interference on canine surface EEnGs by means of a signal averaging process time-locked with the R-wave. Twelve recording sessions were carried out on six conscious dogs in the fasting state. The adaptive filtering technique used increases the signal-to-interference ratio of the raw surface EEnG from 16.7 +/- 6.5 dB up to 31.9 +/- 4.0 dB. In addition to removing ECG interference, this technique has been proven to respect intestinal SB activity, i.e. the EEnG component associated with bowel contractions, despite the fact that they overlap in the frequency domain. In this way, more robust non-invasive intestinal motility indicators can be obtained with correlation coefficients of 0.68 +/- 0.09 with internal intestinal activity. The method proposed here may also be applied to other biological recordings affected by cardiac interference and could be a very helpful tool for future applications of non-invasive recordings of gastrointestinal signals.     

Effect of body surface area calculations on body fat estimates in non-obese and obese subjects

The purpose of the present study was to compare body surface area (BSA) estimates using two equations (Dubois and Dubois versus Livingston) and their respective effects on per cent body fat (%BF) obtained with two molecular approaches of body composition analysis, two-compartment (2C) and five-compartment (5C) models. Body composition data using the 2C model were studied in healthy adults, 432 women (body mass index (BMI): 28.3 +/- 4.4 kg m(-2)) and 147 men (BMI: 26.8 +/- 3.9 kg m(-2)), while another sample of 126 women (BMI: 30.4 +/- 3.7 kg m(-2)) was evaluated using the 5C model. Measures of body volume (BV) assessed by air displacement plethysmography, bone mineral content by dual energy x-ray absorptiometry (DXA) and total-body water by deuterium dilution were used to estimate %BF with the 5C model. Comparison of means and linear regression analysis was performed. Using BSA(Dubois), either in 2C and 5C models, BV and %BF estimates were significantly underestimated compared to results obtained using BSA(Livingston) (p < 0.05). BMI was strongly associated with %BF differences using BSA(Dubois) and BSA(Livingston) in both 2C (men: r = 0.90; women: r = 0.88) and 5C models (r = 0.88). Though %BF(Dubois) and %BF(Livingston) were strongly associated (r(2) = 1.000), some variability was observed on %BF differences using BSA(Dubois) and BSA(Livingston). These findings suggest that BSA calculation is critical in BF estimation, supporting the use of a more accurate equation for non-obese and obese subjects.     

Leukocyte-endothelium interactions after hemorrhagic shock/reperfusion and cecal ligation/puncture: an intravital microscopic study in rat mesentery

Hemorrhagic shock/reperfusion (HS/R) followed by sepsis triggers systemic microcirculatory disturbances that may induce multiple organ failure. The present study evaluated the effects of HS/R and cecal ligation and puncture, followed by necrotic cecal resection/peritoneal lavage (REL) on leukocyte-endothelium interactions at the mesentery. Eighty-one anesthetized Wistar rats (200-250 g) were randomly assigned to a first injury: (1) control-HS-no hemorrhagic shock/no reperfusion group, (2) HS/blood-HS/R with 25% shed blood, and (3) HS/blood + LR-HS/R with 25% of the shed blood + lactated Ringer's solution, 3x shed blood volume. Twenty-four hours post-HS/R, animals were submitted to cecal ligation and puncture and, 24 h thereafter, to REL. Leukocyte-endothelium interactions were assessed by intravital microscopy and intercellular adhesion molecule (ICAM) 1 and P-selectin expression by immunohistochemistry. Lungs were observed for ICAM-1 expression and neutrophil infiltration. Single and double injury induced significant increases in rolling (approximately 2-fold), adherent (approximately 5-fold), and migrated leukocytes (approximately 7-fold); ICAM-1 expression (approximately 1/2-fold), and P-selectin expression (approximately 1/2-fold) at the mesentery compared with control-HS group. REL normalized leukocyte-endothelium interactions at the mesentery in single-injured animals. However, in double-injured rats, adherence and migration of leukocytes decreased but did not normalize. Similar results were observed on ICAM-1 expression and neutrophil infiltration in the lungs from these animals. In conclusion, the current in vivo observation of the mesenteric microcirculation after a double injury followed by REL is a suitable model for the systematic evaluation of the inflammatory reaction at local and distant sites. In addition, data presented herein emphasized the importance of surgical removal of the septic focus in controlling the otherwise lethal sepsis-induced multiple organ dysfunction syndrome.     

Unique gene expression signature by human embryonic stem cells cultured under serum-free conditions correlates with their enhanced and prolonged growth in an undifferentiated stage

Understanding the interaction between human embryonic stem cells (hESCs) and their microenvironment is crucial for the propagation and the differentiation of hESCs for therapeutic applications. hESCs maintain their characteristics both in serum-containing and serum-replacement (SR) media. In this study, the effects of the serum-containing and SR culture media on the gene expression profiles of hESCs were examined. Although the expression of many known embryonic stem cell markers was similar in cells cultured in either media, surprisingly, 1,417 genes were found to be differentially expressed when hESCs cultured in serum-containing medium were compared with those cultured in SR medium. Several genes upregulated in cells cultured in SR medium suggested increased metabolism and proliferation rates in this medium, providing a possible explanation for the increased growth rate of nondifferentiated cells observed in SR culture conditions compared with that in serum medium. Several genes characteristic for cells with differentiated phenotype were expressed in cells cultured in serum-containing medium. Our data clearly indicate that the manipulation of hESC culture conditions causes phenotypic changes of the cells that were reflected also at the level of gene expression. Such changes may have fundamental importance for hESCs, and gene expression changes should be monitored as a part of cell culture optimization aiming at a clinical use of hESCs for cell transplantation.     

Clinical manifestations due to severe plasminogen deficiency: a case report

Plasminogen deficiency is a rare, destructive, and badly defined disorder. Recurrent and progressive gingival nodular hyperplasia with ulceration would appear to be an unreported complication caused by this deficiency. In some of the reported cases, gingival hyperplasia occurred in association with an eye disease called ligneous conjunctivitis. Including this case report, only 11 patients with proven functional plasminogen and oral lesions have been reported in the literature in English. The purpose of this paper was to present the case of a child patient with recurrent clinical manifestations caused by severe plasminogen deficiency who responded positively to corticosteroid treatment.     

The pediatric patient at a maxillofacial service: Eye prosthesis

Congenital absence or loss of the ocular globe during childhood causes psycho-social and cosmetic disorders and compromise the normal development of the orbital region. The literature relating to congenital or acquired etiology, due to trauma or disease, demonstrates the necessity of prevention and early detection in order to minimize the sequelae and disturbances in orbital growth. Installation of an eye prosthesis is essential to the rehabilitation process, so as to produce satisfactory development of the region. In order to characterize a profile of the child patient with this condition, a survey was carried out at the Prosthetic Eye sector, Out-patient Clinic, Discipline of Maxillofacial Prosthodontics, School of Dentistry, University of S?o Paulo (FOUSP), during the period from 1988 to 2003. The 124 (14.02%) patients within the age group of 0-13 years registered for ocular prosthesis were divided into a first group of 64 patients (51.62%) with 0-7 years, and a second group of 60 patients (48.38%) with 8-13 years. Fifty nine were girls and 65 were boys. No statistical significance was observed regarding the distribution of genders in the two analyzed age groups (p = 0.069). However, there was statistical significance at the level of 0.01 in relation to etiology, with higher prevalence of congenital and pathological disturbances in the younger group and traumatic occurrences in the older group. The etiology also presented variation according to the gender, at the significance level of 0.05, where girls presented three times less trauma than boys in the older age group. The necessity of prosthetic ocular repair was evenly distributed along the childhood period and the eye losses that required prosthetic treatment equally affected both genders. However, the etiology of eye loss varied according to the considered gender and age bracket.     

Vitamin D receptor polymorphisms and diseases

The vitamin D endocrine system is central to the control of bone and calcium homeostasis. Thus, alterations in the vitamin D pathway lead to disturbances in mineral metabolism. Furthermore, a role for vitamin D has been suggested in other diseases, like cancer, diabetes and cardiovascular disease. Expression and nuclear activation of the vitamin D receptor (VDR) are necessary for the effects of vitamin D. Several genetic variations have been identified in the VDR. DNA sequence variations, which occur frequently in the population, are referred to as "polymorphisms" and can have biological effects. To test whether there is a linkage between VDR polymorphisms and diseases, epidemiological studies are performed. In these studies, the presence of a variation of the gene is studied in a population of patients, and then compared to a control group. Thus, association studies are performed, and a link among gene polymorphisms and diseases can be established. Since the discovery of VDR polymorphisms a number of papers have been published studying its role in bone biology, renal diseases, diabetes, etc. The purpose of this review is to summarize the vast amount of information regarding vitamin D receptor polymorphisms and human diseases, and discuss its possible role as diagnostic tools.     

Bilirubin toxicity to human erythrocytes: a review

Neonatal jaundice, a physiologic condition reflecting the interplay between developmentally modulated changes in bilirubin production and metabolism, affects virtually all newborn infants. Usually, it is an entirely benign process that is resolved at the end of the first week of life without treatment or sequelae. However, in a small percentage of neonates, unconjugated hyperbilirubinemia can pose a neurotoxic risk especially in the presence of aggravating conditions such as a diminished albumin binding capacity and/or affinity, acidosis, displacing drugs and prematurity. Although neuronal cells are considered the main target for unconjugated bilirubin (UCB) toxicity, circulating cells are also affected during neonatal hyperbilirubinemia. Moreover, the UCB ability to cause hemolysis shall further aggravate neonatal jaundice through a vicious circle. In this review, we summarize the most relevant data obtained by our group regarding UCB toxicity and the role of some risk factors for kernicterus. In order to improve the risk assessment of neurotoxicity it is essential to understand the underlying mechanisms of UCB pathophysiology.     

Drusen deposits associated with aging and age-related macular degeneration contain nonfibrillar amyloid oligomers

Protein misfolding and aggregation are thought to underlie the pathogenesis of many amyloid diseases, such as Alzheimer and Parkinson diseases, whereby a stepwise protein misfolding process begins with the conversion of soluble protein monomers to prefibrillar oligomers and progresses to the formation of insoluble amyloid fibrils. Drusen are extracellular deposits found in aging eyes and in eyes afflicted with age-related macular degeneration (AMD). Recent characterizations of drusen have revealed protein components that are shared with amyloid deposits. However, characteristic amyloid fibrils have thus far not been identified in drusen. In this study, we tested the hypothesis that nonfibrillar oligomers may be a common link in amyloid diseases. Oligomers consisting of distinct amyloidogenic proteins and peptides can be detected by a recently developed antibody that is thought to recognize a common structure. Notably, oligomers exhibit cellular toxicity, which suggests that they play a role in the pathogenesis of neurodegenerative diseases. Through use of the anti-oligomer antibody, we came to observe the presence of nonfibrillar, toxic oligomers in drusen. Conversely, no reactivity was observed in age-matched control eyes without drusen. These results suggest that amyloid oligomers may be involved in drusen biogenesis and that similar protein misfolding processes may occur in AMD and amyloid diseases.