Saturated salt solution: a further step to a formaldehyde-free embalming method for veterinary gross anatomy.

In the field of veterinary anatomy, most of the specimens used in practical sessions are perfused with fixatives. Thus, they can be used for a longer time, reducing the number of animals for educational purposes. Formalin is the most commonly used fixative, consisting of a 37% formaldehyde solution. However, formaldehyde is a powerful irritant of the eyes and airways and is considered carcinogenic, causing nasopharyngeal cancer in exposed workers and professionals. In the present study, we explored an alternative method to avoid the use of formaldehyde in specimens used for gross anatomy practical sessions. We propose an inexpensive, non-toxic fixative that is available worldwide, such as sea salt. This method consists of a continuous perfusion of saturated salt solution for a period of 6-8 h, enabling drainage of the solution to avoid a weight increase of the specimen, and allowing salt to be retained in the tissue. The method is based on recirculation of the saturated salt solution instead of maceration. Perfused specimens retained their natural consistency and joint mobility, with no blood, resembling a piece of meat from the slaughterhouse. They could be used immediately without a maceration period, or stored in the fridge until use and then kept in a bath of saturated salt solution for future conservation. In the case of the former, no refrigeration was needed. The specimens did not have an irritating or offensive smell, and could be used for long sessions (several hours per day) and stored for long periods. However, the blood vessels used for perfusion determine the results: a less invasive approach (through common carotid arteries) gave good preservation of the musculoskeletal system, whereas more invasive access to cannulate the abdominal aorta and vena cava caudalis was required to achieve better preservation of the viscera. In conclusion, we propose that perfusion followed by immersion in a saturated salt solution is a good alternative method for the preservation of specimens used in the practical teaching of gross veterinary anatomy. It is a very simple and inexpensive technique, and is much healthier for users than traditional formalin. Moreover, specimens can be preserved for prolonged periods, and maintain a similar appearance and consistency to fresh material.

Chest computed tomography findings of patients infected with Covid-19 and their association with disease evolution stages.

INTRODUCTION: To describe CT findings in patients with confirmed Covid-19 infection and correlate them with the disease evolution stages. METHODS: This is a historical cohort observational analytical study carried out with outpatients, inpatients, and emergency patients from a private hospital in Maceió/AL, Brazil. The final sample consisted of 390 patients with positive RT-PCR for Covid-19 with available laboratory tests and chest CT results. RESULTS: The most frequent initial symptoms were cough, fever, dyspnea and headache. The most commonly found comorbidities were hypertension, diabetes mellitus and obesity. A total of 22% of the CT scans showed no alterations; ground-glass opacity was the most frequently found one. There was a significant association between age, comorbidities, pulmonary involvement, ground-glass opacity, mosaic attenuation and percentage of pulmonary involvement with death. The analysis of the disease stages showed a significant association with laboratory data (CRP and platelet levels), ground-glass opacity and mosaic attenuation with the disease evolution stages in relation to the days since symptom onset. CONCLUSION: The disease evolution of Covid-19 occurs in stages, and this study describes tomographic findings in patients with confirmed Covid-19 infection and shows they vary depending on the disease evolution stages. IMPLICATIONS FOR PRACTICE: This paper provides important addition to the various records that have been accumulated through the Covid-19 pandemic.

Characterisation of foxing stains in eighteenth to nineteenth century drawings using non-destructive techniques.

The reddish-brown, brown or yellowish stains of circular or irregular shape known as foxing spots have been fully described in conservation literature but still, this phenomenon does not find any scientific agreement since many hypotheses have been raised concerning their origin. In this work a contribution to foxing definition not only focussed on its appearance but also reported on its chemical information. For this purpose foxing stains present in drawings from two Portuguese artists dated from the eighteenth to nineteenth centuries were observed under ultra-violet light and optical microscope and analysed by three non-invasive spectroscopy techniques. The observations carried out on the stains provided information on their surface morphology. The use of energy-dispersive X-ray fluorescence revealed a variation on the elemental content between foxing and paper region. Although the results from X-ray diffraction analysis showed no signs of cellulose degradation in foxing stains, Fourier-transformed infrared analysis revealed the presence of oxide groups. Both the information on the chemical nature and surface morphology of the stains achieved in this study will contribute to increase foxing formation information and develop future protocols for conservation purposes.

Entropy production as a tool for characterizing nonequilibrium phase transitions.

Nonequilibrium phase transitions can be typified in a similar way to equilibrium systems, for instance, by the use of the order parameter. However, this characterization hides the irreversible character of the dynamics as well as its influence on the phase transition properties. Entropy production has been revealed to be an important concept for filling this gap since it vanishes identically for equilibrium systems and is positive for the nonequilibrium case. Based on distinct and general arguments, the characterization of phase transitions in terms of the entropy production is presented. Analysis for discontinuous and continuous phase transitions has been undertaken by taking regular and complex topologies within the framework of mean-field theory (MFT) and beyond the MFT. A general description of entropy production portraits for Z_{2} ("up-down") symmetry systems under the MFT is presented. Our main result is that a given phase transition, whether continuous or discontinuous has a specific entropy production hallmark. Our predictions are exemplified by an icon system, perhaps the simplest nonequilibrium model presenting an order-disorder phase transition and spontaneous symmetry breaking: the majority vote model. Our work paves the way to a systematic description and classification of nonequilibrium phase transitions through a key indicator of system irreversibility.

Reference equations for the 6-minute walk distance in healthy Portuguese subjects 18-70 years old.

INTRODUCTION: Six-minute walk test (6MWT) is used for evaluating functional exercise capacity. To the best of our knowledge, there are no reference equations to predict six-minute walk distance (6MWD) for the Portuguese population. The aims of the present study were to measure anthropometric data and 6MWD in a sample of healthy Portuguese population, to establish reference equations to predict 6MWD and to compare our equations with those obtained by previously published studies. METHODS: We conducted an observational prospective study. We consecutively recruited 158 healthy 18-70 years old subjects from Porto district, who performed two 6MWTs using a standardized protocol. The best 6MWD was used for further analysis. RESULTS: The mean 6MWD was 627.8m (SD=73.3m). The variables that were significantly associated with the 6MWD were age, sex, BMI and ΔHR (Heart Rateat the end of the test-HRat rest). We found three explanatory models for 6MWD, the best with an explanatory power of 38%: 6MWD=721.7-1.6×Age-4.0×BMI+0.9×ΔHR+58.4×Sex. We verified that 6MWD decreased 1.6m per year of age, and 4.0m per unit of BMI and increased 0.892m per beat per minute. Moreover, on average, males walk 58.4m more than females (p<0.001). Applying equations from other studies to our population resulted in an overestimation or underestimation of the 6MWD. CONCLUSION: The present study was the first to describe the 6MWD in healthy Portuguese people aged 18-70 years old and to propose predictive equations. These can contribute to improving the evaluation of Caucasian Mediterranean patients with diseases that affect their functional capacity.

Severe asthma in obese patients: Improvement of lung function after treatment with omalizumab.

INTRODUCTION: Asthma and obesity have a considerable impact on public health and their prevalence is increasing. Obesity is a known risk factor for asthma and can make it more difficult to control. Omalizumab is recommended in patients with severe allergic persistent asthma. The aim of this study was to assess the impact of omalizumab treatment in obese asthmatic patients with poorly controlled severe persistent asthma. METHODOLOGY: A non-interventional, prospective study was conducted, in an outpatient asthma clinic. All patients with severe asthma who started treatment with omalizumab were included and followed over 12 months. The study population was divided into two groups (obese and non-obese) for statistical analysis (descriptive and comparative analysis). RESULTS: Thirty-two patients (19 obese) were followed. After 12 months of omalizumab treatment, there was a statistically significant improvement in body mass index, number of exacerbations in the previous year, rescue medication, disease control and lung function, in the whole population. At the end of the study obese patients had a significantly better lung function (FEV1) than non-obese. DISCUSSION: As described in the literature, there was a significant reduction in the number of exacerbations in the previous year, rescue medication and better disease control, in the whole population. In relation to lung function, about which published data are inconsistent, treatment with omalizumab significantly improved it in obese patients. CONCLUSION: Our study showed that omalizumab significantly improved asthma control, reduced rescue medication and asthma exacerbations in all the population; and for the first time showed that obese patients achieved significantly improved lung function.

Numerical study of a model for nonequilibrium wetting.

We revisit the scaling properties of a model for nonequilibrium wetting [Phys. Rev. Lett. 79, 2710 (1997)], correcting previous estimates of the critical exponents and providing a complete scaling scheme. Moreover, we investigate a special point in the phase diagram, where the model exhibits a roughening transition related to directed percolation. We argue that in the vicinity of this point evaporation from the middle of plateaus can be interpreted as an external field in the language of directed percolation. This analogy allows us to compute the crossover exponent and to predict the form of the phase transition line close to its terminal point.

Time correlation function in systems with two coexisting biological species.

We study a stochastic lattice model describing the dynamics of coexistence of two interacting biological species. The model comprehends the local processes of birth, death, and diffusion of individuals of each species and is grounded on interaction of the predator-prey type. The species coexistence can be of two types: With self-sustained coupled time oscillations of population densities and without oscillations. We perform numerical simulations of the model on a square lattice and analyze the temporal behavior of each species by computing the time correlation functions as well as the spectral densities. This analysis provides an appropriate characterization of the different types of coexistence. It is also used to examine linked population cycles in nature and in experiment.

Interplay between sympathetic nervous system and inflammation in aseptic loosening of hip joint replacement.

Inflammation is a common symptom in joint disorders such as rheumatoid arthritis, osteoarthritis (OA) and implant aseptic loosening (AL). The sympathetic nervous system is well known to play a critical role in regulating inflammatory conditions, and imbalanced sympathetic activity has been observed in rheumatoid arthritis. In AL it is not clear whether the sympathetic nervous system is altered. In this study we evaluated the systemic and local profile of neuroimmune molecules involved in the interplay between the sympathetic nervous system and the periprosthetic inflammation in hip AL. Our results showed that periprosthetic inflammation does not trigger a systemic response of the sympathetic nervous system, but is mirrored rather by the impairment of the sympathetic activity locally in the hip joint. Moreover, macrophages were identified as key players in the local regulation of inflammation by the sympathetic nervous system in a process that is implant debris-dependent and entails the reduction of both adrenergic and Neuropetide Y (NPY)-ergic activity. Additionally, our results showed a downregulation of semaphorin 3A (SEMA3A) that may be part of the mechanism sustaining the periprosthetic inflammation. Overall, the local sympathetic nervous system emerges as a putative target to mitigate the inflammatory response to debris release and extending the lifespan of orthopedic implants.

Portuguese consensus document for the management of alpha-1-antitrypsin deficiency.

Alpha-1-antitrypsin deficiency (AATD) is a genetic autosomal codominant disorder caused by mutations in SERPINA1 gene. It is one of the most prevalent genetic disorders, although it remains underdiagnosed. Whereas at international level there are several areas of consensus on this disorder, in Portugal, inter-hospital heterogeneity in clinical practice and resources available have been adding difficulties in reaching a diagnosis and in making therapeutic decisions in this group of patients. This raised a need to draft a document expressing a national consensus for AATD. To this end, a group of experts in this field was created within the Portuguese Pulmonology Society - Study group on AATD, in order to elaborate the current manuscript. The authors reviewed the existing literature and provide here general guidance and extensive recommendations for the diagnosis and management of AATD that can be adopted by Portuguese clinicians from different areas of Medicine. This article is part of a supplement entitled "Portuguese consensus document for the management of alpha-1-antitrypsin deficiency" which is sponsored by Sociedade Portuguesa de Pneumologia.

Asymptotic behavior of the entropy of chains placed on cylinders.

By using the transfer matrix approach, we investigate the asymptotic behavior of the entropy of flexible chains with M monomers each placed on strips with periodic boundary conditions (cylinders). In the limit of high density of monomers, we study the behavior of the entropy as a function of the density of monomers and the width of the strip, inspired by recent analytical studies of this problem for the particular case of dimers (M=2). We obtain the entropy in the asymptotic regime of high densities for chains with M=2,...,9 monomers, as well as for the special case of polymers, where M-->infinity, and find that the results show a regular behavior similar to the one found analytically for dimers. We also verify that in the low-density limit the mean-field expression for the entropy is followed by the results from our transfer matrix calculations.

Fluoride intake by children at risk for the development of dental fluorosis: comparison of regular dentifrices and flavoured dentifrices for children.

The aim of the present study was to determine fluoride intake by children at risk of dental fluorosis according to the type of dentifrice used. Forty-two volunteers aged between 20 and 30 months, from 2 kindergartens, were supervised while brushing their teeth with regular dentifrices (nominally 1,500 ppm F) and dentifrices flavoured for children (nominally 1,100 ppm F), brushing 3 times with each type in random order to minimize bias. The amount of fluoride ingested was determined by subtracting the weight of dentifrice recovered from the weight used and calculating the mean of the 3 brushings. Fluoride was analyzed with specific electrodes. Parents were asked how often the children brushed their teeth and the daily tooth brushing frequency was used to calculate the daily fluoride intake. The average fluoride intake using regular dentifrices and those flavoured for children was 0.567 +/- 0.300 and 0.630 +/- 0.320 mg F/day, respectively, corresponding to doses of 0.046 +/- 0.023 and 0.051 +/- 0.026 mg F/kg/day (p > 0.05). Fluoride intake was slightly higher with the use of dentifrices flavoured for children. Moreover, the dose to which children were exposed with either type of dentifrice was very close to that which is considered the limit (0.05-0.07 mg F/kg/day).

Mycobacterium avium infection in Portugal.

BACKGROUND: Although the incidence rates of non-tuberculous mycobacteria (NTM) have been increasing in many countries, the basic epidemiology of NTM remains to be fully understood. OBJECTIVE: To assess the incidence, clinical relevance and geographical distribution of NTM disease in Portugal and to identify demographic and clinical characteristics associated with Mycobacterium avium complex (MAC) disease. METHODS: Information stored in an electronic database of all NTM cases reported over an 11-year period was retrospectively reviewed. Significant demographic and clinical characteristics of MAC disease (vs. having any other NTM disease) were determined using multiple logistic regression models. RESULTS: We identified 632 patients, mostly male, native Portuguese, with pulmonary disease, predominantly from Lisbon and Porto. The annual incidence of NTM disease was 0.54 per 100 000 population. The annual number of NTM cases increased throughout the study period. MAC was most frequently isolated. MAC disease was positively (and significantly) associated with being female, age >45 years and human immunodeficiency virus infection. CONCLUSIONS: The increasing incidence of NTM over the study period emphasises the importance of NTM as a public health issue. This study provides important information for health care professionals and a basis for further study of NTM in Portugal.

Does any association exist between Chronic Obstructive Pulmonary Disease and Erectile Dysfunction? The DECODED study.

INTRODUCTION: Erectile dysfunction (ED) is the inability to achieve or maintain an erection for satisfactory sexual activity. Recent studies have shown an association between ED and chronic obstructive pulmonary disease (COPD). However, this issue is often ignored. We aimed to evaluate the ED prevalence in COPD patients and its risk factors and to study the impact of dyspnea in sexual activity. METHODS: Cross-sectional study that included sexually active male patients with COPD. The International Index of Erectile Function (IIEF-5) questionnaire evaluated ED and the Respiratory Experiences with Sexuality Profile (RESP) was used to evaluate the impact of dyspnea on sexual activity. Risk factors for mild-moderate or moderate ED were determined using logistic regression. RESULTS: 84 patients were consecutively assessed for eligibility, 67 were included (median age: 65 years, 13% never-smokers). Twenty two percent had COPD 2011-GOLD A; 22% GOLD B, 14% GOLD C and 42% GOLD D. Fifty-eight patients (87%) had some degree of ED: 26 (45%) mild, 20 (34%) mild-moderate and 12 (21%) moderate ED. ED occurred in all GOLD stages of COPD, mainly in GOLD B and D stages. Higher CAT score was independently associated to mild-moderate/moderate ED. Most patients (85%) reported dyspnea during their sexual activity but 72% had never talked about it with their physician. CONCLUSIONS: ED is highly prevalent among COPD patients and it is more severe in patients with higher CAT scores. Dyspnea affects their sexual activity but this is not a topic often discussed between patients and doctors, something which needs to be improved.

Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular/metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic profiles) are recognized markers of these consequences. Limited data is available on the association of these markers and OSAS's severity/response to positive airway pressure therapy (PAP). MATERIAL AND METHODS: In this prospective study we analyzed polysomnographic and analytical data of male patients admitted to sleep laboratory. The aim was to evaluate metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters and PAP response. One-hundred and three patients were included, and 73 (71%) were OSAS patients. OSAS patients were similar to snorers except for higher body mass index (BMI) and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and insulin resistance, and lower HDL cholesterol in comparison to mild-moderate (p<0.05, p<0.05, p<0.001, p<0.001, p<0.05, respectively). Glycemic profile and triglycerides were slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol (p<0.05, p<0.05, p<0.05, respectively), and in glycemia and LDL cholesterol in severe group only (p<0.05, p<0.05, respectively). RESULTS: This study demonstrated an association between glucose metabolism parameters and triglycerides with OSAS severity underlying the complexity of the process leading to cardiovascular/metabolic complications in this disorder. Moreover, homocysteine, glycemic and lipidic profiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovascular and metabolic protective effect. CONCLUSION: Our study has reinforced the importance of analytical cardiovascular/metabolic evaluation as complementary tool of diagnosis/treatment response in OSAS.

Decellularized human colorectal cancer matrices polarize macrophages towards an anti-inflammatory phenotype promoting cancer cell invasion via CCL18.

Macrophages are frequently identified in solid tumors, playing important roles in cancer progression. Their remarkable plasticity makes them very sensitive to environmental factors, including the extracellular matrix (ECM). In the present work, we investigated the impact of human colorectal tumor matrices on macrophage polarization and on macrophage-mediated cancer cell invasion. Accordingly, we developed an innovative 3D-organotypic model, based on the decellularization of normal and tumor tissues derived from colorectal cancer patients' surgical resections. Extensive characterization of these scaffolds revealed that DNA and other cell constituents were efficiently removed, while native tissue characteristics, namely major ECM components, architecture and mechanical properties, were preserved. Notably, normal and tumor decellularized matrices distinctly promoted macrophage polarization, with macrophages in tumor matrices differentiating towards an anti-inflammatory M2-like phenotype (higher IL-10, TGF-ß and CCL18 and lower CCR7 and TNF expression). Matrigel invasion assays revealed that tumor ECM-educated macrophages efficiently stimulated cancer cell invasion through a mechanism involving CCL18. Notably, the high expression of this chemokine at the invasive front of human colorectal tumors correlated with advanced tumor staging. Our approach evidences that normal and tumor decellularized matrices constitute excellent scaffolds when trying to recreate complex microenvironments to understand basic mechanisms of disease or therapeutic resistance.

Diabetic foot ulcer development risk classifications' validation: A multicentre prospective cohort study.

AIMS: To prospectively validate the existing classifications to stratify subjects with diabetes mellitus (DM) by their risk of diabetic foot ulcer (DFU), in high and low risk settings. METHODS: A prospective multicentre cohort study was conducted, including 446 subjects with DM without active DFU followed in the hospital or primary care setting. Demographic, clinical characterization variables, and those included in the classifications were collected at baseline. Subjects were followed for 1year, until DFU or death. RESULTS: In our sample, with a mean age of 65years, 52% were male; 32 developed a DFU, 7 required an amputation and 18 died. Differences were found between participants' characteristics and classifications' accuracy according to the setting. The great majority of the variables were associated with higher DFU risk. Globally, classifications were highly and equally valid, positive predictive values (PV) were inferior to 40%, negative PV superior to 90% and area under the receiver operating characteristic curve superior to 0.75. DISCUSSION: All the existing classifications are valid to be applied in high risk clinical context and have a very high capacity to categorize as low risk those subjects that will not develop a DFU. Further research is needed in the primary care setting.

Fluctuation-dissipation theorem and the linear Glauber model.

We obtain exact expressions for the two-time autocorrelation and response functions of the -dimensional linear Glauber model. Although this linear model does not obey detailed balance in dimensions d > or = 2, we show that the usual form of the fluctuation-dissipation ratio still holds in the stationary regime. In the transient regime, we show the occurrence of aging, with a special limit of the fluctuation-dissipation ratio, x(infinity) = 1/2, for a quench at the critical point.

Severe leukopenia and liver biochemistry changes in adult rabbits after calicivirus infection.

Calicivirus infection is the major cause of the severe decrease in the stocks of wild and farm rabbits that has occurred worldwide during the last two decades. Adult rabbits (10-weeks-old) were experimentally infected with a calicivirus inoculum that killed all animals by causing rabbit haemorrhagic disease (RHD) within 24-62 h of infection. The rabbits were used to evaluate blood cell numbers and serum biochemistry every 6h, starting 12h after the inoculation of the caliciviruses. No significant changes in blood parameters were observed in most of the rabbits up to 18 h of infection. Severe leukopenia was seen 6h before death of the infected rabbits; both heterophils and lymphocytes contributed to the decrease in circulating white blood cells. Platelets were also severely decreased in number. Marked enhancement in liver enzymes was seen 6-12 h before death of the infected rabbits. There was also evidence both for cholestasis, as expressed by the elevated levels of direct (conjugated) bilirubin, and for hypoglycemia, an alteration that it is likely to contribute for the seizures that rabbits show during the late stages of RHD. Liver ultrastructure of rabbits that died from RHD revealed extensive hepatocyte vacuolization, severe changes in mitochondrial structure, and depletion of glycogen granules. We conclude that: (i) severe leukopenia characterizes the final hours of calicivirus-induced RHD; (ii) hypoglycemia and cholestasis precede death of rabbits from RHD; (iii) the kinetics of liver enzymes allows an accurate prediction of the time of death of rabbits from calicivirus-induced RHD.

Liver enzymes and ultrastructure in rabbit haemorrhagic disease (RHD).

Rabbit haemorrhagic disease (RHD) is caused by a calicivirus infection that kills most adult rabbits 24-72 h after viral inoculation. Two liver enzymes (AST, aspartate aminotransferase, and ALT, alanine aminotransferase) were monitored in blood samples of calicivirus-infected rabbits during the short course of RHD. Values of AST were used to differentiate three stages of hepatocellular degeneration in RHD: mild (up to 20-fold increase in AST), moderate (150-200-fold elevation of AST) and severe (more than 1000-fold elevation in AST). Liver samples of rabbits from these three biochemical stages of hepatocellular degeneration of RHD were studied by transmission electron microscopy to define the fine structure of the hepatocytes. In the mild hepatocellular degeneration there was proliferation (microvesiculation) of the smooth endoplasmic reticulum and swelling of mitochondria into spheroid bodies with loss of cristae. In moderate hepatocellular degeneration, vacuolization of cytoplasm and mitochondrial damage continued to be present, and there was also formation of autophagic vesicles. In the severe hepatocellular degeneration of RHD, the altered mitochondria also showed loss of density of their matrix; rupture of cytoplasmic vacuoles led to the formation of large vesicles. Marked depletion of liver glycogen was also found in this late stage of RHD. These data offer a correlation between biochemical and cytological features of the liver during the hepatocellular degeneration of RHD.