Pulmonary artery pressure response to percutaneous mitral valvuloplasty: Associated factors and clinical implications.

BACKGROUND: Pulmonary hypertension (PH) is a marker of poor outcome in mitral stenosis (MS), which improves after percutaneous mitral valvuloplasty (PMV). However, mechanical interventions for relief of valve obstruction often but not always reduce pulmonary pressures. This study aimed to assess the parameters associated with abnormal pulmonary artery pressure (PAP) response immediately after a successful PMV, and also its impact on long-term outcome. METHODS: A total of 181 patients undergoing PMV for rheumatic MS were prospectively enrolled. Invasive hemodynamic and echocardiographic measures were examined in all patients. Abnormal PAP response was defined as the mean PAP (mPAP) values unchanged at the end of the procedure. Long-term outcome was a composite endpoint of death, mitral valve replacement, repeat PMV, new onset of atrial fibrillation (AF), or stroke. RESULTS: The mean age was 44.1 ± 12.6 years, and 157 patients were women (86.7%). In the overall population, mPAP decreased from 33.4 ± 13.1 mmHg pre to 27.6 ± 9.8 mmHg post (p < 0.001). Following PMV, 52 patients (28.7%) did not have any reduction of mPAP immediately after the PMV. Multivariable analysis adjusting for baseline values of PAP and mitral valve area revealed that AF (Odds ratio [OR] 2.7, 95% [confidence interval] CI 1.3 to 6.7), maximum mitral valve leaflets displacement (OR 0.8, 95% CI 0.7 to 0.9), and post-procedural left ventricular compliance (OR 0.7, 95% CI 0.5 to 0.9) were predictors of a lack of improvement in mPAP. During a median follow-up of 4.4 years, the endpoint was reached in 56 patients (31%). The pulmonary pressure response to PMV was not an independent predictor of long-term events. CONCLUSIONS: In patients with MS undergoing PMV, pulmonary pressures may not reduce immediately after the procedure, despite adequate opening of the valve. Abnormal PAP response can be predicted from baseline clinical and valvular characteristics as well as post-procedural left ventricular compliance. The lack of any immediate reduction in mPAP is not associated with long-term adverse outcomes.

Subcutaneous vacuoles with suppuration and granulomas: a histological clue to atypical mycobacterial infection.

An 83-year-old woman was referred to the Dermatology department with a papular eruption on her left arm, occurring below the scar site of a malignant melanoma in situ, which had been excised 6 months previously. On physical examination, multiple, tender, violaceous papules and nodules inferior to the scar were noted, with central pustules in some of the lesions.

New ethionamide boosters and EthR2: structural and energetic analysis.

Ethionamide (ETH) is a high-profile drug for the treatment of patients with multidrug-resistant Mycobacterium tuberculosis and, in order to produce its inhibitory effects, it needs to be bioactivated by monooxygenase EthA. This process is under the control of the transcriptional repressors EthR and EthR2, so that their inhibition results in the boosting of ethionamide activation. Herein, through crystallographic data and computer simulations, we calculated the interaction binding energies of four inhibitors with improved in vitro potency, namely BDM76060 (PDB ID: 6HS1), BDM72201 (PDB ID: 6HRX), BDM76150 (PDB ID: 6HS2) and BDM72719 (PDB ID: 6HRY), in complexes with the transcriptional repressor EthR2, using density functional theory (DFT) within the molecular fractionation with conjugated caps (MFCC) approach. It was observed that these ligands share the same binding site within a 10.0 Å radius of the EthR2 protein; however, their structural particularities have a significant impact on the global energies of systems. The BDM72201 and BDM72719 components are weakly attached to the binding site, while BDM76060 and BDM76150 components produce stronger bonds, corroborating with experimental studies demonstrating that BDM76060 and BDM76150 are more successful in producing inhibitory effects. BDM76060 and BDM76150 have many functional groups that increase the contact surface with the protein and attract a more significant number of amino acid residues, being able to produce polarities that generate stronger interactions. In the current scenario of a growing number of cases of bacterial resistance, the obtained data can be used to guide clinical trials of these inhibitors and other inhibitors that act on the alternative EthR2 pathway, focusing on improving the activity of ethionamide, its effectiveness, a reduction in the treatment time and exposure to cytotoxic effects.

Persistent inflammation, immunosuppression and catabolism syndrome (PICS) in critically ill children is associated with clinical outcomes: a prospective longitudinal study.

BACKGROUND: Persistent inflammation, immunosuppression and catabolism syndrome (PICS) has been described in critically ill adults and may contribute to unfavourable outcomes. The present study aimed to describe and characterise PICS in critically ill children (PICS-ped) and to verify its association with clinical outcomes. METHODS: A prospective longitudinal study was conducted in a paediatric intensive care unit (PICU) with children aged between 3 months and 15 years. PICS-ped, based on adult definition, was described. PICS-ped was defined as PICU length of stay >14 days; C-reactive protein > 10.0 mg L-1 ; lymphocytes <25%; and any reduction of mid-upper arm circumference Z-score. Clinical, demographic, nutritional status, nutrition therapy parameters and clinical outcomes were assessed. Statistical analysis comprised Mann-Whitney and Fisher's chi-squared tests, as well as logistic and Cox regression. P < 0.05 was considered statistically significant. RESULTS: In total, 153 children were included, with a median age of 51.7 months (interquartile range 15.6-123.4 months), and 60.8% male. The mortality rate was 10.5%. The prevalence of PICS-ped was 4.6%. Days using vasoactive drugs and days using antibiotics were associated with PICS-ped. PICS-ped was associated with mortality in crude (odds ratio = 6.67; P = 0.013) and adjusted analysis (odds ratio = 7.14; P = 0.017). PICS-ped was also associated with PICU and hospital length of stay, as well as duration of mechanical ventilation. Similar results were found in a subset of critically ill children who required mechanical ventilation for more than 48 h. CONCLUSIONS: Children with PICS-ped required antibiotics or vasoactive drugs for a longer period. PICS-ped was associated with poor clinical outcomes in critically ill children. More studies are needed to properly define PICS-ped for this population.

Large-scale Degradation of the Tocantins-Araguaia River Basin.

The Tocantins-Araguaia Basin is one of the largest river systems in South America, located entirely within Brazilian territory. In the last decades, capital-concentrating activities such as agribusiness, mining, and hydropower promoted extensive changes in land cover, hydrology, and environmental conditions. These changes are jeopardizing the basin's biodiversity and ecosystem services. Threats are escalating as poor environmental policies continue to be formulated, such as environmentally unsustainable hydropower plants, large-scale agriculture for commodity production, and aquaculture with non-native fish. If the current model persists, it will deepen the environmental crisis in the basin, compromising broad conservation goals and social development in the long term. Better policies will require thought and planning to minimize growing threats and ensure the basin's sustainability for future generations.

Restless legs syndrome in Wilson's disease: frequency, characteristics, and mimics.

OBJECTIVE: To determine characteristics, clinical significance, frequency, and mimics of restless legs syndrome (RLS) in a cohort of Wilson's disease (WD, n = 42/f = 18), compared to healthy, matched controls. MATERIALS AND METHODS: Structured clinical interviews (patients and caregiving family members), repeated neurological examinations (afternoon and presleep), comprehensive laboratory tests, WD-, RLS-, and sleep-specific rating scales, and video-polysomnography. RESULTS: Thirteen patients with WD (13/42 = 31.0%) clearly fulfilled the five diagnostic criteria of RLS; in eight patients (19.1%), the burden of RLS was clinically significant. The RLS was of moderate severity, equally distributed among sexes, manifested mainly in the evening and before falling asleep, and had developed mostly after clinical manifestation of WD (time elapsed 10.2 ± 14.5 years), still at a young mean age (27.5 ± 11.5 years). The known RLS-associated features were absent (normal iron and kidney parameters) or rare (positive family history, polyneuropathy). Compared to WD patients without RLS, patients with RLS were significantly elder and had suffered longer from WD. WD-specific RLS mimics as well as RLS confounding motor comorbidities (dystonia, tremor, chorea) were frequent and a diagnostic challenge; in difficult cases, the differentiation was reached by clinical observation of the motor behavior in the evening or at nighttime. CONCLUSION: RLS was frequent in this cohort of WD and might be causally related to WD. RLS should be included in the diagnostic work-up of WD. In complex motor disorders, differential diagnosis of RLS might require evening/nighttime examination and video-polysomnography. In WD patients with a clinically significant RLS, treatment with dopaminergic substances may be considered.

Polymorphisms in the melatonin receptor gene promoter and their associations with fertility characteristics in buffalo herd in Eastern Amazon.

Buffalo production is spreading globally because of its economic advantage. Then, it has become necessary to improve the reproductive and productive efficiency of these animals, as well as to look for genetic factors that increase this efficiency. The objectives of this study were to characterize the promoter region of the melatonin 1A receptor gene (MTRN1A), to detect possible SNPs and associate them with fertility characteristics, and identify binding sites of transcription factors involved in the regulation of genetic expression in buffaloes in the Amazon. The conventional PCR method was carried out using the two primers designed from the reference sequence deposited in the GenBank AY52466.1. The products of the PCRs were purified, sequenced, and subsequently edited and aligned. Twenty-six SNPs were found, where 73% presented allele frequencies of wild nucleotides above 0.5, and 73% presented deviations from the Hardy-Weinberg equilibrium (P < 0.05) and FIS varying between 0.06 and 1.00, characterizing high degrees of inbreeding within the population. A block of ACAA deletion (position -1483) was observed in 25% of samples. The associations between these SNPs and reproductive characteristics were observed for calving interval and 5 SNPs: -1289, -1139, -911, -724, and -656 (P < 0.05), and three other SNPs: -1395, -724, and -94 (P < 0.05) were associated significantly with age at first calving, and were not associated with calving concentration. The promoter region was characterized by the different types of binding factors, where only 11 sites are significantly strong enough for transcription factor bindings. The ACAA deletion also exhibited a strong association with transcription factors. As a result, it would be necessary to test the SNPs above with other reproductive characteristics of economic relevance to approve the gene as a strong candidate for the selection of buffaloes in the Amazon.

Quality improvement and geographical indication of cachaça (Brazilian spirit) by using locally selected yeast strains.

AIMS: In order to improve the quality and to create a biological basis for obtainment of the protected denomination of origin (PDO), indigenous yeast were isolated and characterized for use in Salinas city (the Brazilian region of quality cachaça production). MATERIAL AND METHODS: Seven thousand and two hundred yeast colonies from 15 Salinas city distilleries were screened based on their fermentative behaviour and the physicochemical composition of cachaça. Molecular polymorphic analyses were performed to characterize these isolates. RESULTS: Two Saccharomyces cerevisiae strains (nos. 678 and 680) showed appropriate characteristics to use in the cachaça production: low levels of acetaldehyde and methanol, and high ethyl lactate/ethyl acetate ratio respectively. They also presented polymorphic characteristics more closely related between themselves even when compared to other strains from Salinas. CONCLUSIONS: The application of selected yeast to cachaça production can contribute for the improvement of the quality product as well as be used as a natural marker for PDO. SIGNIFICANCE AND IMPACT OF THE STUDY: This study suggests that the use of selected yeast strains could contribute to obtain a cachaça similar to those produced traditionally, while getting wide acceptation in the market, yet presenting more homogeneous organoleptic characteristics, and thus contributing to the PDO implementation.

European Society of Coloproctology consensus on the surgical management of intestinal failure in adults.

Intestinal failure (IF) is a debilitating condition of inadequate nutrition due to an anatomical and/or physiological deficit of the intestine. Surgical management of patients with acute and chronic IF requires expertise to deal with technical challenges and make correct decisions. Dedicated IF units have expertise in patient selection, operative risk assessment and multidisciplinary support such as nutritional input and interventional radiology, which dramatically improve the morbidity and mortality of this complex condition and can beneficially affect the continuing dependence on parenteral nutritional support. Currently there is little guidance to bridge the gap between general surgeons and specialist IF surgeons. Fifteen European experts took part in a consensus process to develop guidance to support surgeons in the management of patients with IF. Based on a systematic literature review, statements were prepared for a modified Delphi process. The evidence for each statement was graded using Oxford Centre for Evidence-Based Medicine Levels of Evidence. The current paper contains the statements reflecting the position and practice of leading European experts in IF encompassing the general definition of IF surgery and organization of an IF unit, strategies to prevent IF, management of acute IF, management of wound, fistula and stoma, rehabilitation, intestinal and abdominal reconstruction, criteria for referral to a specialist unit and intestinal transplantation.

Modification of trout sperm membranes associated with activation and cryopreservation. Implications for fertilizing potential.

We investigated the effects of two trout sperm activation solutions on sperm physiology and membrane organization prior to and following cryopreservation using flow cytometry and investigated their impact on in vitro fertility. Overall, frozen-thawed samples had greater phospholipid disorder when compared with fresh samples (high plasma membrane fluidity; P < 0.0001) and sperm activated with water also had high plasma membrane fluidity when compared to sperm activated with Lahnsteiner solution (LAS; P < 0.0001). Following cryopreservation water activated samples had membranes with greater membrane protein disorganization compared with LAS but the membrane protein organization of LAS samples was similar to samples prior to freezing (P < 0.0001). Post-thaw water activation resulted in significant increases in intracellular calcium compared to LAS (P < 0.002). In vitro fertility trials with frozen-thawed milt and LAS activation resulted in greater fertility (45%) compared to water activated samples (10%; P < 0.0001). Higher fertility rates correlated with lower intracellular calcium with water (R(2) = -0.9; P = 0.01) and LAS (R(2) = -0.85; P = 0.03) activation. Greater plasma membrane phospholipid (R(2) = -0.89; P = 0.02) and protein (R(2) = -0.84; P = 0.04) disorder correlated with lower water activation fertility rates. These membrane organization characteristics only approached significance with LAS activation in vitro fertility (P = 0.09, P = 0.06, respectively). Potentially the understanding of sperm membrane reorganizations and the physiology associated with activation following cryopreservation may enable users in a repository or hatchery setting to estimate the fertilizing potential of a sample and determine its value.

Immersed diffraction grating refractometers of liquids.

In this work, we report the development, construction, and the performance of two liquid refractometers that use a reflective diffraction grating immersed in a test liquid. The liquid is contained in a transparent glass cell with a rectangular cross section. The grating is oriented in such a way that the propagation directions of the incident beam and the beam diffracted by the lower part of the grating immersed in the liquid are perpendicular. In this configuration, the refractive index is determined by measuring the angle of the zeroth-order diffraction beam coming from the upper part of the grating, which is in contact with air. The diffractive refractometers (DR-1 and DR-2) have different angle measurement procedures and different light detection systems, and their advantages and drawbacks are pointed out. In the experiments, precisions of the order of 10-5 and 10-4 for DR-1 and DR-2 are achieved, respectively. The performances of both systems are compared with the performance of a commercial Abbe refractometer in the measurement of sugar and NaCl aqueous solutions.

Prevalence of food allergy in infants and pre-schoolers in Brazil.

BACKGROUND: Food allergy is an increasing problem in public health, especially in childhood. Its incidence has increased in the last decade. Despite this, estimates of the actual incidence and prevalence are uncertain. The aim of this study was to estimate the prevalence of food allergy in infants and pre-schoolers. METHODS: The parents of 3897 children completed questionnaires on the occurrence of any reaction to food. Children with parentally reported reactions were selected for further examination including a clinical interview, physical examination, allergic tests, and if necessary, oral food challenge to conclude the diagnosis of FA. RESULTS: The estimated prevalence of allergy in children aged 4-59 months was 0.61%, being, 1.9% in infants and 0.4% in pre-schoolers. Among the 604 patients physicians evaluated with parent-reported FA, 24 (4%) had a confirmed diagnosis of food allergy, and 580 (96%) were excluded in the remaining. Of these, approximately half (51/52.6%) of 97 infants and (128/48%) of 487 pre-schoolers already performed the diet exclusion suspected food for a period of time. CONCLUSION: This study shows that high overall prevalence of parental belief of current food allergy however the same was not observed in the in physician-diagnosed food allergy. The prevalence of food allergy was lower than that observed in the literature. This study alerts health professionals to the risk entailed by overestimation of cases of food allergy and unnecessary dietary exclusion, which may result in impairment in growth and development of children, especially in their first years of life.

Novel polymorphism in exon 1 of the melatonin receptor gene unassociated with reproductive characteristics of buffaloes in the Amazon Region.

The objective of this study was to sequence part of the exon 1 in the melatonin receptor 1A gene (MTRN1A) in buffaloes to detect a novel polymorphism with which to associate reproductive characteristics, such as age at first birth and the interval between births, in buffaloes from the northeastern region of the State of Pará (Brazil). Buffalo hair samples (77) were collected from the Terra Firme region of Pará. DNA was extracted and polymerase chain reactions (PCRs) were carried out with a primer that was designed using the GenBank accession No. AY524665 reference sequence. PCR products were purified and sequenced. After editing and analysis of the sequences, a mutation was observed at the 62nd position in exon 1 of MTRN1A (T↔C), which corresponded with a change in the 21st amino acid from leucine to proline. All possible genotypes were observed, with the most common being genotype CC (0.481). The allele frequencies were T = 0.377 and C = 0.623. Statistical analysis of FIS showed inbreeding within the sample group (FIS = 0.397) and deviations from the Hardy- Weinberg equilibrium were observed (P < 0.05). Associations between genotypes and reproductive characteristics were not significant (P > 0.05). Although the related SNP was not synonymous, there were no observable effects on the reproductive characteristics under investigation. As such, it would be ideal to detect other SNPs in exon 1 of the MTRN1A gene that can be associated with reproductive characteristics in Amazonian buffaloes.

Corrigendum Polymorphism in the melatonin receptor gene in buffalo populations of the Brazilian Amazon - Genet. Mol. Res. 15 (2): gmr.15027960.

The correction is only in the name of the first author and should be: E.M. Barbosa(1), B.B. Souza(2), R.C. Guimarães(2), J.S.N. Azevedo(3), E.C. Gonçalves(4), H.F.L. Ribeiro(2), S.T. Rolim Filho(2), E. Silva Filho(2).

Homology modeling and molecular dynamics of ß-defensin II variants in Amazonian sheep.

ß-defensins are capable of creating pores in the bacterial membrane. In this study, we aim to determine the structure of 3 different sheep ß-defensin 2 (SBD-2) sequences by molecular modeling. A herd of 47 sheep from the Centre for Ovine and Caprine Research of Pará was selected for this investigation. The AA, AG, and GG alleles were found on ß-defensin sequences. We used homology modeling and molecular dynamic simulations to generate 3D models of peptides and they were successfully validated. The proteins are structurally very similar to classic defensins composed of 3 ß-sheets and 3 disulfide bonds. Variations in the organization of the tertiary structure and distribution of charged residues were found between AA, AG, and GG alleles. In this study, we were able to characterize and show the structure of 3 SBD-2 gene variants for the first time in Amazonian sheep. Results demonstrated that these variants are similar in structures to classic ß-defensins, but contain more positives charges, which may indicate an increase in efficacy.

Polymorphisms in the leptin gene promoter in Brazilian beef herds.

Brazil is the world's largest producer of beef cattle; however, the quality of its herds needs to be improved. The use of molecular markers as auxiliary tools in selecting animals for reproduction with high pattern for beef production would significantly improve the quality of the final beef product in Brazil. The leptin gene has been demonstrated to be an excellent candidate gene for bovine breeding. The objective of this study was to sequence and compare the leptin gene promoter of Brazil's important cattle breeds in order to identify polymorphisms in it. Blood samples of the Nellore, Guzerat, Tabapuã, and Senepol breeds were collected for genomic DNA extraction. The genomic DNA was used as a template for polymerase chain reaction (PCR) to amplify a 1575-bp fragment, which in turn was sequenced, aligned, and compared between animals of different breeds. Twenty-three single nucleotide polymorphic sites, including transitions and transversions, were detected at positions -1457, -1452, -1446, -1397, -1392, -1361, -1238, -963,-901, -578, -516, -483, -478, -470, -432, -430, -292, -282, -272, -211, -202, -170, and -147. Additionally, two insertion sites at positions -680 and -416 and two deletion sites at positions -1255 and -1059 were detected. As the promoter region of the leptin gene has been demonstrated to vary among breeds, these variations must be tested for their use as potential molecular markers for artificial selection of animals for enhanced beef production in different systems of bovine production in Brazil.

Genetic polymorphisms in ß-defensin II gene in Amazon sheep from Brazil.

The northern region of Brazil produces a large number of sheep, with Pará being the largest sheep breeding state in the region. In the Amazon region, livestock production is a challenge due to the high diversity of pathogens affecting humans and animals. Defensins are antimicrobial peptides acting as a first barrier against micro-organisms and present high variation in different organisms. The objective of this study was to detect polymorphisms in exon II in ß-defensin II in Amazon sheep. The gene was amplified by PCR from DNA extracted from 47 sheep blood samples from the Santa Inês breed. Products were sequenced, aligned and analyzed. Three single nucleotide polymorphism (SNP) positions were observed with transition substitutions (A↔G) at positions 1643, 1659, and 1750. The 1643 and 1750 SNPs showed a low variability and significant deviations from Hardy-Weinberg equilibrium (HWE) (P < 0.05) meanwhile the SNP 1659 showed moderate absence of genetic variability and deviation from HWE (P > 0.05). Polymorphisms at 1643 and 1659 were predicted to modify amino acids in the peptide chain (isoleucine to valine and arginine to lysine, respectively) with no effects on protein function. Results from this study suggest that SNPs are important markers for ß-defensin II efficiency studies on the immune system of sheep in the Brazilian Amazon.

Utility of chest CT for differentiating primary and secondary achalasia.

AIM: To determine the computed tomography (CT) findings of primary and secondary achalasia and to assess the utility of CT for differentiating these conditions. METHODS: A computerized search revealed 13 patients with primary achalasia and 15 with secondary achalasia who underwent chest CT during a 10-year period. The images were reviewed to determine whether there was distal oesophageal narrowing (including the length/contour of narrowing), oesophageal dilation, oesophageal wall thickening (including degree/symmetry/pattern of thickening), a soft-tissue mass at the gastro-oesophageal junction, mediastinal adenopathy, or other findings of malignant tumour. RESULTS: Eleven (85%) of 13 patients with primary achalasia had distal oesophageal narrowing at CT that was smooth in all patients; four (31%) had oesophageal wall thickening that was smooth and symmetric in all patients; none had a soft-tissue mass at the gastro-oesophageal junction or mediastinal lymphadenopathy; and two (15%) had pulmonary metastases from unrelated lung cancers. In contrast, 12 (80%) of 15 patients with secondary achalasia had distal oesophageal narrowing at CT; 11 (73%) had distal oesophageal wall thickening that was nodular/lobulate and asymmetric in seven (64%) and smooth and symmetric in four (36%); six (40%) had a soft-tissue mass at the gastro-oesophageal junction; seven (47%) had mediastinal lymphadenopathy; and all 15 had other findings of malignant tumour. CONCLUSION: CT is a useful technique for differentiating primary and secondary achalasia. Distal oesophageal wall thickening that is nodular/lobulate and asymmetric, a soft-tissue mass at the gastro-oesophageal junction, mediastinal lymphadenopathy, and pulmonary, hepatic, or osseous metastases are findings that favour secondary achalasia.

Overexpression of the activated form of the AtAREB1 gene (AtAREB1ΔQT) improves soybean responses to water deficit.

Abscisic acid-responsive element binding protein (AREB1) is a basic domain/leucine zipper transcription factor that binds to the abscisic acid (ABA)-responsive element motif in the promoter region of ABA-inducible genes. Because AREB1 is not sufficient to direct the expression of downstream genes under non-stress conditions, an activated form of AREB1 (AREB1ΔQT) was created. Several reports claim that plants overexpressing AREB1 or AREB1ΔQT show improved drought tolerance. In our studies, soybean plants overexpressing AREB1ΔQT were characterized molecularly, and the phenotype and drought response of three lines were accessed under greenhouse conditions. Under conditions of water deficit, the transformed plants presented a higher survival rate (100%) than those of their isoline, cultivar BR 16 (40%). Moreover, the transformed plants displayed better water use efficiency and had a higher number of leaves than their isoline. Because the transgenic plants had higher stomatal conductance than its isoline under well-watered conditions, it was suggested that the enhanced drought response of AREB1ΔQT soybean plants might not be associated with altered transpiration rates mediated by ABA-dependent stomatal closure. However, it is possible that the smaller leaf area of the transgenic plants reduced their transpiration and water use, causing delayed stress onset. The difference in the degree of wilting and percentage of survival between the 35S-AREB1ΔQT and wildtype plants may also be related to the regulation of genes that protect against dehydration because metabolic impairment of photosynthesis, deduced by an increasing internal CO2 concentration, was not observed in the transgenic plants.

Effect of flow rate and temperature on transmembrane blood pressure drop in an extracorporeal artificial lung.

INTRODUCTION: Transmembrane pressure drop reflects the resistance of an artificial lung system to blood transit. Decreased resistance (low transmembrane pressure drop) enhances blood flow through the oxygenator, thereby, enhancing gas exchange efficiency. This study is part of a previous one where we observed the behaviour and the modulation of blood pressure drop during the passage of blood through artificial lung membranes. METHODS: Before and after the induction of multi-organ dysfunction, the animals were instrumented and analysed for venous-venous extracorporeal membrane oxygenation, using a pre-defined sequence of blood flows. RESULTS: Blood flow and revolutions per minute (RPM) of the centrifugal pump varied in a linear fashion. At a blood flow of 5.5 L/min, pre- and post-pump blood pressures reached -120 and 450 mmHg, respectively. Transmembrane pressures showed a significant spread, particularly at blood flows above 2 L/min; over the entire range of blood flow rates, there was a positive association of pressure drop with blood flow (0.005 mmHg/mL/minute of blood flow) and a negative association of pressure drop with temperature (-4.828 mmHg/(°Celsius). These associations were similar when blood flows of below and above 2000 mL/minute were examined. CONCLUSIONS: During its passage through the extracorporeal system, blood is exposed to pressure variations from -120 to 450 mmHg. At high blood flows (above 2 L/min), the drop in transmembrane pressure becomes unpredictable and highly variable. Over the entire range of blood flows investigated (0-5500 mL/min), the drop in transmembrane pressure was positively associated with blood flow and negatively associated with body temperature.