Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

A computational model for the mitochondrial respiratory chain that appropriately balances mass, charge, and free energy transduction is introduced and analyzed based on a previously published set of data measured on isolated cardiac mitochondria. The basic components included in the model are the reactions at complexes I, III, and IV of the electron transport system, ATP synthesis at F1F0 ATPase, substrate transporters including adenine nucleotide translocase and the phosphate–hydrogen co-transporter, and cation fluxes across the inner membrane including fluxes through the K+/H+ antiporter and passive H+ and K+ permeation. Estimation of 16 adjustable parameter values is based on fitting model simulations to nine independent data curves. The identified model is further validated by comparison to additional datasets measured from mitochondria isolated from rat heart and liver and observed at low oxygen concentration. To obtain reasonable fits to the available data, it is necessary to incorporate inorganic-phosphate-dependent activation of the dehydrogenase activity and the electron transport system. Specifically, it is shown that a model incorporating phosphate-dependent activation of complex III is able to reasonably reproduce the observed data. The resulting validated and verified model provides a foundation for building larger and more complex systems models and investigating complex physiological and pathophysiological interactions in cardiac energetics.

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A Biophysical Model of the Mitochondrial Respiratory System and Oxidative Phosphorylation

A thorough understanding of the physical and chemical changes that occur in the body after death is critical for accurate interpretation of gross and microscopic pathology at autopsy. Furthermore, knowledge of the postmortem processes and the factors that affect them will aid in the estimation of the postmortem interval (PMI). The estimation of the PMI is important in many human and animal death investigations. Despite many decades of research, accuracy in estimation of the time of death has not significantly improved, and no single method can be reliably used to accurately estimate the time of death. Great care should be taken when formulating such an estimate, for it is dependent on multiple circumstantial and environmental factors, and the accuracy and precision of the estimate decrease as the PMI increases. The majority of the research in the field has been conducted on human bodies, but many relevant conclusions may be drawn regarding the expected postmortem changes in animals and the estimation of the PMI. The veterinary pathologist must use great caution when attempting to extrapolate data and apply formulas designed for use in humans. Methods reviewed include gross changes, microscopic changes, temperature-based methods, postmortem chemistry, molecular methods, microbial assay, ocular changes, radiography, entomology, and others. Although only several of these methods are currently practical for use in the workup of cases, it is expected that future research will result in improved techniques with enhanced accuracy in the estimation of the PMI, which will benefit both human and veterinary forensic investigations.

https://journals.sagepub.com/doi/pdf/10.1177/0300985816629720

Postmortem Changes in Animal Carcasses and Estimation of the Postmortem Interval.

Calcium is a key ion and is known to mediate signalling pathways between cytosol and mitochondria and modulate mitochondrial energy metabolism. To gain a quantitative, biophysical understanding of mitochondrial Ca2+ regulation, we developed a thermodynamically balanced model of mitochondrial Ca2+ handling and bioenergetics by integrating kinetic models of mitochondrial Ca2+ uniporter (CU), Na+–Ca2+ exchanger (NCE), and Na+–H+ exchanger (NHE) into an existing computational model of mitochondrial oxidative phosphorylation. Kinetic flux expressions for the CU, NCE and NHE were developed and individually parameterized based on independent data sets on flux rates measured in purified mitochondria. While available data support a wide range of possible values for the overall activity of the CU in cardiac and liver mitochondria, even at the highest estimated values, the Ca2+ current through the CU does not have a significant effect on mitochondrial membrane potential. This integrated model was then used to analyse additional data on the dynamics and steady-states of mitochondrial Ca2+ governed by mitochondrial CU and NCE. Our analysis of the data on the time course of matrix free [Ca2+] in respiring mitochondria purified from rabbit heart with addition of different levels of Na+ to the external buffer medium (with the CU blocked) with two separate models – one with a 2: 1 stoichiometry and the other with a 3: 1 stoichiometry for the NCE – supports the hypothesis that the NCE is electrogenic with a stoichiometry of 3: 1. This hypothesis was further tested by simulating an additional independent data set on the steady-state variations of matrix free [Ca2+] with respect to the variations in external free [Ca2+] in purified respiring mitochondria from rat heart to show that only the 3: 1 stoichiometry model predictions are consistent with the data. Based on these analyses, it is concluded that the mitochondrial NCE is electrogenic with a stoichiometry of 3: 1.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.2008.151977

Analysis of cardiac mitochondrial Na+–Ca2+ exchanger kinetics with a biophysical model of mitochondrial Ca2+ handing suggests a 3: 1 stoichiometry

Data from 31P-nuclear magnetic resonance spectroscopy of human forearm flexor muscle were analyzed based on a previously developed model of mitochondrial oxidative phosphorylation (PLoS Comp Bio 1:...

Oxidative ATP synthesis in skeletal muscle is controlled by substrate feedback

PURPOSE: To evaluate the antioxidant effects of enemas containing aqueous extract of Ilex paraguariensis, comparing segments with and without fecal stream and correlating the segments with the duration of intervention. METHODS: Twenty-six Wistar rats were subjected to a diversion of the fecal stream in the left colon by a proximal colostomy and distal mucosal fistula. The rats were distributed randomly into two experimental groups of 13 animals each based on the time of sacrifice after surgical procedure (two or four weeks). Each group was then divided into two experimental subgroups that received either second daily enemas containing 0.9% saline solution or aqueous extract of Ilex paraguariensis at 0.2g/100g. Colitis was diagnosed by histopathological analysis and the detection of oxidative tissue damage by measuring the levels of malondialdehyde. The Mann-Whitney test was used to compare the tissue levels of malondialdehyde between colon segments with and without fecal stream in each experimental group, and the Kruskal-Wallis test was used to verify the variance between the levels of oxidative stress according the duration of the irrigation; both tests determined significance at 5% (p<0.05). RESULTS: The levels of malondialdehyde in the animals subjected to intervention in the colon with saline with and without fecal stream after two and four weeks of irrigation were 0.05±0.006 and 0.06±0.006, and 0.05± 0.03 and 0.08 ±0.02, respectively. The malondialdehyde levels in the animals irrigated with Ilex paraguariensis with and without fecal stream after two and four weeks of irrigation were 0.010±0.002 and 0.02±0.004, and 0.03±0.007 and 0.04±0.01, respectively. After two and four weeks of intervention, the levels of malondialdehyde were lower in the animals irrigated with Ilex paraguariensis regardless of the time of irrigation (p=0.0001 and p=0.002, respectively). CONCLUSION: The daily rectal application of enemas containing aqueous extract of Ilex paraguariensis decreases oxidative tissue damage in the colon without fecal stream regardless of the time of irrigation.

/pdf/reduction-in-oxidative-stress-levels-in-the-colonic-mucosa-5au8f9s787.pdf

Reduction in oxidative stress levels in the colonic mucosa without fecal stream after the application of enemas containing aqueous Ilex paraguariensis extract.

Potential definition of the time of death from autolytic myocardial cells: a morphometric study.

O desenvolvimento da Fisioterapia, aliado as mudancas na educacao e na saude, faz com que a autonomia e os dilemas eticos do fisioterapeuta sejam maiores a cada dia, expandindo seu papel no cuidado do paciente. Para alem do Codigo de Etica, as nocoes de Bioetica sao centrais no preparo de graduandos para os desafios profissionais. Este estudo verificou a capacidade de tomar decisoes eticas de alunos no ultimo ano de Fisioterapia de duas universidades na cidade de Sao Paulo, das quais uma oferece no curriculo a disciplina Bioetica e a outra nao. Cinquenta alunos de cada universidade responderam a um questionario sobre dilemas eticos correspondentes a artigos do Codigo de Etica; cada questao oferecia tres alternativas de resposta: uma bioetica, outra referente ao Codigo e uma nao-etica. As respostas foram analisadas estatisticamente. Os resultados mostraram um bom preparo etico em pouco mais de metade dos alunos das duas universidades, sugerindo que ambas oferecem preparo etico similar aos graduandos, independente da diferenca curricular. No entanto, os alunos da universidade que oferece Bioetica tiveram resultados significantemente melhores nos quesitos referentes a relacao com outros profissionais da saude, sugerindo que essa disciplina oferece melhores condicoes para o relacionamento interprofissional, fator importante tanto na pratica clinica quanto para elevar o status da Fisioterapia.

/pdf/o-preparo-bioetico-na-graduacao-de-fisioterapia-3gm5rvbkq9.pdf

O preparo bioético na graduação de Fisioterapia

Purpose: To develop a method of differential diagnosis to drowning, due to analysis of the alveolar macrophages quantitative, in rats submitted to induced drowning in fresh water and salty water Methods: Were used 15 male adult rats Wistar EPM1, weight 360g (SD=21,3), randomized in three groups: G1- Control; G2- Fresh water; G3- Salty water, each one with n=5 The animals have been anesthetized and tracheostomized to insert a cannula inside the trachea, for drowning induction The lungs have been removed, weighed, prepared for histology and colored by immunohistochemistry The macrophages have been counted in both lungs (right and left) of each animal The statistical test used was ANOVA (SPSS10) with p G2>G1 with p=0,0001 in each comparison The weight of lungs of G3 and G2 was higher than G1, with p>0,0001, however G3 and G2 do not possess difference statistics in the weight of lungs Conclusion: The developed diagnostic method was efficient in rats The results, if expanded, will be able to assist

/pdf/use-of-the-histopathology-in-the-differential-diagnosis-of-xgzpazj1th.pdf

Use of the histopathology in the differential diagnosis of drowning in fresh and salty water: an experimental model establishment in rats 1 Uso da histopatologia no diagnóstico diferencial de afogamento em água doce e água salgada: estabelecimento de modelo experimental em ratos

PURPOSE: To develop a method of differential diagnosis to drowning, due to analysis of the alveolar macrophages quantitative, in rats submitted to induced drowning in fresh water and salty water METHODS: Were used 15 male adult rats Wistar EPM-1, weight 360g (SD=21,3), randomized in three groups: G1- Control; G2- Fresh water; G3- Salty water, each one with n=5 The animals have been anesthetized and tracheostomized to insert a cannula inside the trachea, for drowning induction The lungs have been removed, weighed, prepared for histology and colored by immunohistochemistry The macrophages have been counted in both lungs (right and left) of each animal The statistical test used was ANOVA (SPSS10) with p G2>G1 with p=0,0001 in each comparison The weight of lungs of G3 and G2 was higher than G1, with p>0,0001, however G3 and G2 do not possess difference statistics in the weight of lungs CONCLUSION: The developed diagnostic method was efficient in rats The results, if expanded, will be able to assist the Forensic Pathology for technique of low cost and high trustworthiness

/pdf/use-of-the-histopathology-in-the-differential-diagnosis-of-2aejyjc4vn.pdf

Marcos de Almeida

Papers

Reduction in oxidative stress levels in the colonic mucosa without fecal stream after the application of enemas containing aqueous Ilex paraguariensis extract.

Potential definition of the time of death from autolytic myocardial cells: a morphometric study.

O preparo bioético na graduação de Fisioterapia

Use of the histopathology in the differential diagnosis of drowning in fresh and salty water: an experimental model establishment in rats 1 Uso da histopatologia no diagnóstico diferencial de afogamento em água doce e água salgada: estabelecimento de modelo experimental em ratos

Use of the histopathology in the differential diagnosis of drowning in fresh and salty water: an experimental model establishment in rats