Physical activity level and factors associated with perceived stress among Peruvian university professors during the COVID-19 pandemic.

Introduction: The COVID-19 pandemic led to the transition to remote work, triggering variations in stress and physical activity (PA), associated with context-specific instability. Objective: To identify the association between perceived stress (PS) and the level of physical activity (PA) and explore its relationship with the sociodemographic, family, work and individual characteristics of professors working remotely during the COVID-19 pandemic. Material and methods: Cross-sectional analytical study based on a virtual survey of professors. PS was assessed using the Perceived Stress Scale (PSS-14), and PA using an International Physical Activity Questionnaire. The prevalence of high PS and the association with PA were estimated using a Poisson regression analysis with robust variance that estimated crude prevalence ratios (cPR) and adjusted prevalence ratios (aPR) with a 95% confidence interval (CI). Five models were developed to assess associations of PS and PA with sociodemographic, family, work, and individual variables. Results: The information of 191 professors was analyzed; 39.27% were women, aged 52 (41-60). The prevalence of high stress was 47.12%. The age and being head of household did not show significant individual associations with PS. However, the regression analysis assessing the association of PS and other factors showed that compared to the moderate PA group, a statistically significant association was found between stress and high PA (aPR = 0.19; 0.06-0.59), low PA (aPR = 1.43; 1.02-2.01), mainly influenced by age, being head of household and sleep quality. Conclusion: Stress was associated with PA level, family and individual factors. These findings allow identifying characteristics, such as being head of household, age and quality of sleep among teachers, as being associated with a higher probability of having high stress. Subsequent studies should consider the role of individuals and working conditions as part of occupational health surveillance, given the presence of hybrid education in the education sector.

Latitudinal prevalence gradient of multiple sclerosis in Latin America.

BACKGROUND: Multiple sclerosis (MS) has a unique geographical distribution that reflects both genetic and environmental factors. Many studies have shown a positive correlation between MS frequency and latitude across both large and small geographical regions. However, scarce data have been published on the epidemiology of MS in Latin America and no study has evaluated latitudinal variation. OBJECTIVE: To evaluate the effect of latitude on MS prevalence in Latin America. METHODS: We conducted a systematic review of MS prevalence during January 2011. Prevalence rates were collected from eligible publications. The effect of latitude on prevalence was analyzed using linear regression. RESULTS: A total of ten studies were eligible for analysis, corresponding to six countries, spanning from Panama to Argentina. The crude prevalence of MS ranged from 0.75 to 21.5 per 100,000. We found a strong and significant association between prevalence and latitude (r(2) 0.8; p < 0.001) and determined an increase in prevalence of 0.33 per 100,000 per degree latitude. CONCLUSION: Our findings suggest a latitudinal prevalence gradient of MS in Latin American countries between Panama and Argentina.

Olive oil and health: summary of the II international conference on olive oil and health consensus report, Jaén and Córdoba (Spain) 2008.

Olive oil (OO) is the most representative food of the traditional Mediterranean Diet (MedDiet). Increasing evidence suggests that monounsaturated fatty acids (MUFA) as a nutrient, OO as a food, and the MedDiet as a food pattern are associated with a decreased risk of cardiovascular disease, obesity, metabolic syndrome, type 2 diabetes and hypertension. A MedDiet rich in OO and OO per se has been shown to improve cardiovascular risk factors, such as lipid profiles, blood pressure, postprandial hyperlipidemia, endothelial dysfunction, oxidative stress, and antithrombotic profiles. Some of these beneficial effects can be attributed to the OO minor components. Therefore, the definition of the MedDiet should include OO. Phenolic compounds in OO have shown antioxidant and anti-inflammatory properties, prevent lipoperoxidation, induce favorable changes of lipid profile, improve endothelial function, and disclose antithrombotic properties. Observational studies from Mediterranean cohorts have suggested that dietary MUFA may be protective against age-related cognitive decline and Alzheimer's disease. Recent studies consistently support the concept that the OO-rich MedDiet is compatible with healthier aging and increased longevity. In countries where the population adheres to the MedDiet, such as Spain, Greece and Italy, and OO is the principal source of fat, rates of cancer incidence are lower than in northern European countries. Experimental and human cellular studies have provided new evidence on the potential protective effect of OO on cancer. Furthermore, results of case-control and cohort studies suggest that MUFA intake including OO is associated with a reduction in cancer risk (mainly breast, colorectal and prostate cancers).

Platelet activation in patients with advanced gastric cancer.

The aim of this study was to evaluate platelet activation in gastric cancer patients with regard to histopathological classification and the presence of distant metastases, by using platelet morphological parameters: MPV, L-PLT, MPC, as well as quantitative evaluation of surface receptor expression: CD41a, CD61, CD42b, CD62P, by flow cytometry at the resting state and after TRAP activation. In gastric cancer patients higher values of MPV and LP, as well as decreased MPC values were determined. Quantitative evaluation of surface antigen expression also revealed higher number of CD41a, CD61 and CD62P molecules, as compared with the platelets in the control group. Significant decrease of CD42b molecules' number after TRAP incubation, and the increased CD41a, CD61 and CD62P expression also point to the retained reactivation capacity of platelets. Good correlation between morphological parameters and the number of CD62P molecules indicates the usefulness of routine tests in evaluation of platelet activation.

Divergent mechanisms of cis9, trans11-and trans10, cis12-conjugated linoleic acid affecting insulin resistance and inflammation in apolipoprotein E knockout mice: a proteomics approach.

Conjugated linoleic acids (CLA) affect atherogenesis, but mechanisms are not well understood. We explored how two isomers of CLA, cis9, trans11-CLA and trans10, cis12-CLA, affected lipid and glucose metabolism, as well as hepatic protein expression, in apolipoprotein E knockout mice. After 12 wk of intervention, plasma triglyceride, NEFA, and glucose concentrations were significantly higher in the trans10, cis12-CLA group, whereas plasma triglyceride, NEFA, glucose, and insulin concentrations were significantly lower in the cis9, trans11-CLA group, compared with control mice consuming linoleic acid. Proteomics identified significant up- or down-regulation of 113 liver cytosolic proteins by either CLA isomer. Principal component analysis revealed that the treatment effect of cis9, trans11-CLA was mainly explained by the up-regulation of different posttranslational forms of heat shock protein 70 kD. In contrast, the treatment effect of trans10, cis12-CLA was mainly explained by up-regulation of key enzymes in the gluconeogenic, beta-oxidation, and ketogenesic pathways. Correlation analysis again emphasized the divergent effects of both CLA isomers on different pathways, but also revealed a linkage between insulin resistance and increased levels of hepatic serotransferrin. Thus, our systems biology approach provided novel insights into the mechanisms by which individual CLA isomers differentially affect pathways related to atherogenesis, such as insulin resistance and inflammation.

Effect of modification on physicochemical and biological properties of haptoglobin. VI. Reaction with azlactone of p-nitrobenzoyl-valine.

The azlactone of p-nitrobenzoyl-valine (Nbz-Val) has been used for modification of xi-amino groups of lysine in haptoglobin type 1-1, in hemoglobin, and in the haptoglobin-hemoglobin complex. By the use of this reagent 95% of amino groups in haptoglobin and 90% in hemoglobin have been blocked without any changes in peroxidase activity of the formed complexes: Nbz-Val.haptoglobin with hemoglobin, Nbz-Val. hemoglobin with haptoglobin, and Nbz-Val.(haptoglonin-hemoglobin). After reduction and reoxidation, Nbz-Val.haptoglobin was found to retain 90% of peroxidase activity when complexed with hemoglobin. Beta chains separated either from haptoglobin or Nbz-Val.haptoglobin showed 15% of peroxidase activity in the complex with hemoglobin, alpha chains of the same origin were completely inactive. Whereas recombination of haptoglobin from alpha and beta chains resulted in 42% hemoglobin-binding capacity, renaturation of Nbz-Val.haptoglobin from separated subunits was found to proceed with almost 100% yield. In immunodiffusion with rabbit anti-haptoglobin or anti-Nbz-Val.haptoglobin sera, preparations of haptoglobin and Nbz-Val.haptoglobin after reduction and reoxidation or after recombination from separated subunits gave similar precipitation arcs showing the reaction of immunological identity.

Molecular cloning and sequence of the cynomolgus monkey apolipoprotein A-II gene.

A clone containing the coding region for cynomolgus monkey (Macaca fascicularis) apolipoprotein A-II has been isolated from a cynomolgus genomic DNA library. The gene spans 1.4 kilobases (kb). The complete nucleic acid sequence of the apolipoprotein A-II gene has been determined, establishing that the gene is interrupted by three intervening sequences of 170, 273 and 394 bp, respectively. The open reading frame encodes a protein of 100 amino acids, and shows 94% sequence similarity with its human equivalent. Both apolipoproteins have identical signal peptide. A noticeable feature is the substitution of mature human Cys-6 for Ser. This change explains the existence of cynomolgus apolipoprotein A-II as a monomer and may have important consequences in the kinetics of this apolipoprotein.

Nucleotide sequences of the Macaca fascicularis apolipoprotein C-III and A-IV genes.

The cynomolgus monkey (Macaca fascicularis) apolipoprotein C-III and apolipoprotein A-IV genes have been isolated from a cynomolgus genomic DNA library and completely sequenced. These genes span 3.1 and 2.8 kilobases (kb), respectively. Apolipoprotein C-III gene is interrupted by three intervening sequences of 613, 135 and 1699 bp, respectively. The open reading frame encodes a protein of 99 amino acids which is 87% similar to the human. The cynomolgus mature protein is 79 residues long. Thr-74 is also present what might allow the formation of O-glycosidic linkage observed in the human protein. Apolipoprotein A-IV gene consist of two intervening sequences of 352 and 774 bp, respectively. The open reading frame encodes a protein of 429 amino acids which is 87% similar to the human. The cynomolgus mature protein is 409 residues long, 33 amino acids longer than the human, due to an insertion of 33 residues in its COOH-terminal region. This insertion is mainly composed of glutamine and glutamic acid, which confers cynomolgus apolipoprotein a higher hydrophilicity.

Effect of fat feeding on human intestinal apolipoprotein B mRNA levels and editing.

Our purpose was to assess the effect of a fat-rich meal on intestinal apolipoprotein B (apoB) mRNA levels and editing. We obtained jejunal biopsies from eight healthy adults in the fasting state and 3 h after a meal containing 1 g/kg of fat. In the fasting state, 93% of the apoB mRNA contained the editing sequence resulting in apoB-48 production. Feeding induced no significant changes in apoB mRNA levels or editing. Our data are consistent with the concept that the significant increase in apoB-48 within triglyceride-rich lipoproteins in postprandial plasma is not due to alterations in apoB gene expression or editing.

Internalization study using EDTA-prepared hepatocytes for receptor-mediated endocytosis of haemoglobin-haptoglobin complex.

We have demonstrated the internalization of haemoglobin-haptoglobin (Hb-Hp) complex using rat hepatocytes prepared by EDTA perfusion, followed by Percoll. The isolated hepatocytes exhibited a saturation curve of the binding of fluorescein isothiocyanate-labelled haemoglobin-haptoglobin complex (FITC-Hb-Hp. Furthermore, competition between the binding of FITC-Hb-Hp and unlabelled Hb to the hepatocytes, was observed. The cells exhibited approximately 9 x 10(4) 'high affinity sites' (Kd approximately 1.2 microM) for the Hb-Hp complex. The data in toto suggest the presence of only one type of receptor i.e. the high affinity receptor (in both affinity and number of sites per cell). The results were similar to those obtained from rat hepatocytes prepared by collagenase digestion [1]. In order to verify whether EDTA-prepared hepatocytes could be used for the study of receptor-mediated endocytosis, the internalization of pre-bound Hb-Hp in the isolated hepatocytes was assessed by two methods. First, acid-insensitive FITC-Hb-Hp time-dependently increased following incubation at 37 degrees C. Secondly, Hb-Hp became inaccessible to the exogenous FITC-anti-haemoglobin antibody. These processes were dependent on ATP, but independent of Ca2+ and stimulated by GTP. The results demonstrate that the receptor-mediated endocytosis of Hb-Hp occurred in the EDTA-prepared hepatocytes.

Hemoglobin binding sites on renal brush-border membranes.

Prolonged exposure of renal tubules to hemoglobin markedly reduces kidney function and eventually leads to acute renal failure called pigment nephropathy. Intracellular hemoglobin toxicity is one of main pathomechanisms involved in the disease development. However, the process in which hemoglobin is taken up by renal tubular epithelium has not been characterized so far. Isolated renal brush-border membranes of the rat and radioiodinated rat and human hemoglobins were used. Binding properties were examined by the use of rapid filtration technique. Partial isolation of hemoglobin binding proteins was achieved by affinity chromatography. Our experiments showed that both human and rat hemoglobins can be specifically bound to renal brush-border membranes by one class of low affinity (Kd, 7.7 microM) and high capacity (Bmax, 0.18 nmol/mg protein) binding sites. The sites were relatively selective for hemoglobin. Albumin did not compete with hemoglobin. Cationic molecules cytochrome C and lysine exhibited some competition while strong competition of myoglobin was observed. The binding was affected by EGTA indicating a Ca2+ requirement for the interaction. There was a rise in binding in pH 5.4. Fall in binding activity after preincubation of the membranes with peptidases suggested the proteinaceous nature of the binding sites. Affinity chromatography of membrane proteins extract yielded heterogeneous preparation consisting of proteins with molecular masses of 110, 72, 38 and 27 kDa respectively. The existence of binding sites for hemoglobin in renal brush-border membranes strongly suggests that uptake of the protein by tubular epithelia occurs via adsorptive endocytosis. Increased binding of hemoglobin to the membranes under acidic conditions may explain exacerbation of hemoglobinuric acute renal failure in aciduric states.

Effects of dietary fat amount and saturation on the regulation of hepatic mRNA and plasma apolipoprotein A-I in rats.

The effects of the amount of dietary fat and saturation together with cholesterol both on hepatic apolipoprotein A-I gene mRNA levels and on plasma levels of this apolipoprotein were studied in male rats. To achieve these goals, seven groups of male Wistar rats were established: control group (n=5) consuming chow diet; cholesterol group (n=4) fed on a chow diet containing 0.1% (w/w) cholesterol; coco group (n=5) fed on a chow diet containing 0.1% (w/w) cholesterol and 40% coconut oil; corn group (n=5) fed on a chow diet containing 0.1% (w/w) cholesterol and 40% corn oil; and three olive groups consuming a chow diet containing 0.1% (w/w) cholesterol and percentages of 5 (n=5), 10 (n=4) and 40% (n=5), respectively, of olive oil. Animals were kept on these diets for 2 months and then sacrificed for lipoprotein, apolipoprotein and hepatic mRNA analysis. Dietary cholesterol by itself was hypercholesterolemic when compared to chow diet, an effect that was mainly due to an increase in LDL-cholesterol. Corn oil had a hypocholesterolemic action, whether compared to chow or to cholesterol diet, due to a reduction in HDL-cholesterol as well as LDL-cholesterol. HDL-cholesterol levels of 40% olive oil diet were lower than those corresponding to coconut oil and higher than those found in corn oil diet. When compared to control or cholesterol diets, plasma apoA-I concentration appeared significantly increased in coconut and 40% olive oil diets. Coconut oil or corn oil diets did not induce any significant change in apoA-I mRNA compared to control or cholesterol diets. Compared to cholesterol diet, 40 and 10% olive oil diets induced a significant increase in the expression of this message. A positive and significant (r=0.97, P<0.01) correlation between plasma apolipoprotein A-I concentration and its hepatic mRNA, was observed when the amount of dietary olive oil was 40% (w/w). A significant negative (r=-0.97, P<0.01) correlation was found in the corn oil group and no significant association was observed in the remaining groups. Based on the increased plasma levels in coconut oil and in high percentage olive oil diets, and the differences between these two diets for mRNA expression, it can be concluded that different fatty acid containing diets regulate apolipoprotein A-I through different mechanisms, and these mechanisms could be modulated by the fat intake.

Reduced progression of atherosclerosis in apolipoprotein E-deficient mice with phenylhydrazine-induced anemia.

Epidemiological and experimental studies suggest that circulating erythrocytes play a role in the incidence of coronary heart disease. We investigated the influence of phenylhydrazine (PHZ)-induced anemia on the formation of atherosclerotic lesions in apo E-deficient mice on regular chow and on a high-fat, high-cholesterol diet during 10 weeks. The repeated doses of PHZ caused sustained anemia throughout the study, changes in the physical characteristics of erythrocytes and increased reticulocyte count. The lesions of the anemic animals were smaller than in the controls and this was even more evident in mice fed with the atherogenic diet. A positive correlation was found between circulating red blood cells at the end of the experiment and the area of aortic lesion. There was also a negative association between the lesion and the reticulocyte count. This reduced progression of atherosclerotic lesions is independent of nutritional status or the lipoprotein cholesterol distribution. The results suggest that mechanisms related to the number of circulating red blood cells may have a significant influence on the development of atherosclerosis.

Differential effect of dietary fat saturation and cholesterol on hepatic apolipoprotein gene expression in rats.

The effects of dietary cholesterol and fat saturation on hepatic apolipoprotein A-I, A-II, A-IV, B, C-I, C-III, E and LDL receptor mRNA levels were studied in male rats. Animals were maintained for 2 months on a high fat diet (40% w/w) containing 0.1% cholesterol. Two groups of control animals received either chow diet or chow plus 0.1% cholesterol, while experimental groups received as their fat supplement coconut, corn or olive oil. Olive oil fed animals had higher levels of hepatic apo A-I than the control cholesterol group (1.6 +/- 0.3 vs. 0.8 +/- 0.2). Apo E mRNA levels were 50% and 72% higher in animals consuming the saturated (coconut) and unsaturated (corn and olive) fat diet than the control cholesterol group. Apo B and apo C-I mRNA levels were not affected by the experimental conditions. Apo A-IV mRNA increased between 66% and 127% in groups in which cholesterol was present. LDL receptor mRNA increased 2 times in the corn fed group compared with the control groups. These results indicate that the expression of genes coding for products involved in lipoprotein metabolism have a differential susceptibility to dietary fat saturation and cholesterol.

Diets enriched in unsaturated fatty acids enhance apolipoprotein A-I catabolism but do not affect either its production or hepatic mRNA abundance in cynomolgus monkeys.

To determine the mechanisms whereby dietary fatty acids influence high density lipoprotein (HDL) cholesterol and apolipoprotein (apo) A-I concentrations, ten cynomolgus monkeys were fed each of three experimental diets enriched in saturated (SAT), monounsaturated (MONO), or polyunsaturated (POLY) fatty acids in a crossover design consisting of three 13-week periods, with each animal serving as its own control. Each diet contained 30% of energy as fat with 0.22 mg cholesterol/kcal and differed solely by the isocaloric substitution of fatty acids as 18% of total energy calories. The replacement of dietary saturated fatty acids with either monounsaturated or polyunsaturated fatty acids, respectively, resulted in significant reductions of plasma total cholesterol (-17%; -30%), HDL cholesterol (-32%; -41%), and apo A-I (-37%; -44%) concentrations, while no significant differences were noted in plasma lipid or apo A-I concentrations when the MONO and POLY phases were compared. Although the MONO and POLY diets were similar in their effects on plasma lipids and apolipoproteins, the HDL of monkeys fed the POLY diet, as compared with either the SAT or the MONO diets, contained more cholesteryl ester and phospholipid but less total protein, resulting in a significantly lower total lipid to protein constituent ratio. Metabolic experiments revealed that the significantly lower plasma apo A-I concentrations observed during both the MONO and POLY phases relative to SAT were directly attributable to enhanced HDL apo A-I catabolism. Conversely, neither HDL apo A-I production rates nor hepatic apo A-I mRNA concentrations were significantly affected by dietary fatty acid perturbation in this study. Taken together, these data indicate that fractional catabolic rate is the predominant mechanism by which dietary fatty acids differentially modulate circulating concentrations of HDL apo A-I in this species when all other dietary variables are held constant.

Elimination from rat circulation of goat and sheep haptoglobin and their complexes with rat haemoglobin.

The rate of elimination from rat circulation of 125I-labelled human, goat and sheep haptoglobin, and their complexes with rat haemoglobin was studied. The clearance of human haptoglobin-rat haemoglobin complex from rat circulation was about 5 times faster than that of free haptoglobin. For sheep and goat haptoglobin and their complexes with rat haemoglobin the rate of elimination was identical, the half-life time t 1/2 ranging from 8 to 9 h.

Elimination of bovine haptoglobin from rat circulation.

The rate of elimination from rat circulation of bovine or rat haptoglobin, of their complexes with homologous haemoglobin, and of preparations deprived of the terminal sialic acid (asialo-haptoglobin), was studied. The rate of elimination was identical for bovine haptoglobin and its complexes with bovine or rat haemoglobin (the half-life time, t1/2, was 10 h). The half-life time of complexes of rat haptoglobin with bovine or rat haemoglobin was about 2 h, and it was much shorter than t1/2 for rat haptoglobin (13 h). The shortest half-life time was observed for bovine and rat asialo-haptoglobin, 35 and 15 min, respectively. The elimination curves showed a biphasic or triphasic character, depending on the rate of elimination.

Preparation and some properties of the haemoglobin-binding protein of bovine blood.

Bovine haptoglobin was prepared from sera which showed peroxidase activity in the complex with haemoglobin. The procedure consisted of precipitation with ammonium sulphate at 0.5 saturation, affinity chromatography on Sepharose 4B coupled to bovine apoglobin, and gel filtration on Sepharose 4B. The preparation was heterogeneous, migrating in 7.5% polyacrylamide gel electrophoresis at pH 8.3 as four haemoglobin-binding bands. On immunoelectrophoresis with bovine antiserum the preparation formed a single precipitin arc with the mobility of alpha 2-globulin; the preparation was found to be a glycoprotein, the sugar moiety of which amounted to 16%.

Elimination of goat haemoglobin and its complexes with goat haptoglobin from goat and rat circulation.

The rate of elimination from rat and goat circulation of 125I-labelled goat haemoglobin and its complexes with human and goat haptoglobin in goat circulation, was studied. The half-life time t1/2 of haemoglobin in rat circulation was 1.5h, whereas in goat circulation -- 4 h, and was 10 times shorter than t1/2 for its complexes.

Studies on the structure of haptoglobin and the haptoglobin-haemoglobin complex by spin and fluorescence labelling.

Human haptoglobin (Hp) of the 1-1 type incorporated one spin or fluorescence marker per molecule; the markers were found in the beta chain. Formation of the complex between spin-labelled Hp and haemoglobin or antibody caused conformational changes in the Hp molecular, evidenced by increased participation in the electron paramagnetic resonance spectrum of the component bound with the slowly rotating marker. From fluorescence-labelled Hp, the beta chain was isolated and cleaved by CNBr; only in one of the obtained peptides, one out of 4 histidine residues was modified with the marker.