Oxidative stress in skin fibroblasts cultures from patients with Parkinson's disease

Background  

In the substantia nigra of Parkinson's disease (PD) patients, increased lipid peroxidation, decreased activities of the mitochondrial complex I of the respiratory chain, catalase and glutathione-peroxidase, and decreased levels of reduced glutathione have been reported. These observations suggest that oxidative stress and mitochondrial dysfunction play a role in the neurodegeneration in PD. We assessed enzymatic activities of respiratory chain and other enzymes involved in oxidative processes in skin fibroblasts cultures of patients with PD.     

The Severity of Nocturnal Hypoxia but Not Abdominal Adiposity Is Associated with Insulin Resistance in Non-Obese Men with Sleep Apnea

Background

Beyond obesity, sleep apnea syndrome is frequently associated with excess abdominal adiposity that could contribute to the deteriorated cardiometabolic risk profile of apneic patients.

Methods

The present study addressed the respective contribution of the severity of sleep apnea syndrome and excess abdominal adiposity to the cardiometabolic risk profile of 38 non obese men with polysomnography-diagnosed sleep apnea syndrome (apnea-hypopnea index >15 events/hour). These otherwise healthy men performed a 75g-oral glucose tolerance test (OGTT) with plasma lipid/inflammatory and redox profiles. Twenty-one apneic men with high-waist circumference (>94 cm) were compared to 17 apneic men with low-waist circumference.

Results

Apneic men with high-waist circumference had higher AUC glucose and AUC insulin than apneic men with low-waist circumference. Accordingly, apneic men with high-waist circumference had higher hepatic insulin resistance as reflected by higher HOMA-resistance index, and lower global insulin sensitivity as reflected by lower insulin sensitivity index of Matsuda (derived from OGTT). The sleep structure and the apnea-hypopnea index were not different between the two groups. However, apneic men with high-waist circumference presented with lower mean nocturnal oxyhemoglobin (SpO₂). In the 38 men, waist circumference and mean nocturnal SpO₂ were inversely correlated (r = −0.43, p = 0.011) and were both associated with plasma glucose/insulin homeostasis indices: the higher the waist circumference, the lower the mean nocturnal SpO₂, the lower the insulin-sensitivity. Finally, in multivariable regression model, mean nocturnal SpO₂ and not waist circumference was associated with insulin-resistance.

Conclusion

Thus, excess abdominal adiposity in non obese apneic men was associated with a deteriorated insulin-sensitivity that could be driven by a more severe nocturnal hypoxemia.     

Evaluation of the viability and germination of tempisque [<i>Sideroxylon capiri</i> (A.DC.) Pittier Sapotaceae]

The tempisque (Sideroxylon capiri) is a tree native to Mexico used by the rural population for housing construction, poles and hedges, as fuel (wood) and also for fodder and ornamental purposes, among others. It is considered an endangered species. In order to contribute to its preservation and sustainable management, it was considered important to determine the proportion of viable seeds, the loss of viability due to storage period and the germination process by applying pregerminative treatments. We found that freshly collected seeds showed 100% viability, which decreased to 0% after 5 months of storage. According to the cumulative germination significant differences between treatments (p≤0.01) were found. It was observed that seeds can accelerate their time of germination with the previous exposure of 24 h in water at room temperature. The soaking treatment in water for 24 h at room temperature obtained final germination of 55%, while with the control 39% was reached. Soaking in hydrogen peroxide and scarification were the treatments with lower germination percentage (33 and 23%, respectively). To get a higher percentage of germinated seeds in a short time, it is necessary to give a soaking treatment in water for 24 h before sowing.     

Processing of vitamin A and E in the human gastrointestinal tract

We aimed to provide basic data on the processing of vitamin A and E in the human gastrointestinal tract and to assess whether the size of emulsion fat globules affects the bioavailability of these vitamins. Eight healthy men received intragastrically two lipid formulas differing in their fat-globule median diameter (0.7 vs. 10. 1 microm. Formulas provided 28 mg vitamin A as retinyl palmitate and 440 mg vitamin E as all-rac alpha-tocopherol. Vitamins were measured in gastric and duodenal aspirates, as well as in chylomicrons, during the postprandial period. The gastric emptying rate of lipids and vitamin A and E was similar. The free retinol/total vitamin A ratio was not significantly modified in the stomach, whereas it was dramatically increased in the duodenum. The proportion of ingested lipid and vitamins was very similar in the duodenal content. The chylomicron response of lipids and vitamins was not significantly different between the two emulsions. Our main conclusions are as follows: 1) there is no significant metabolism of vitamin A and E in the human stomach, 2) the enzyme(s) present in the duodenal lumen is significantly involved in the hydrolysis of retinyl esters, and 3) the size of emulsion fat globules has no major effect on the overall absorption of vitamin A and E.     

Higher‐order assemblies of oligomeric cargo receptor complexes form the membrane scaffold of the Cvt vesicle

Selective autophagy is the mechanism by which large cargos are specifically sequestered for degradation. The structural details of cargo and receptor assembly giving rise to autophagic vesicles remain to be elucidated. We utilize the yeast cytoplasm‐to‐vacuole targeting (Cvt) pathway, a prototype of selective autophagy, together with a multi‐scale analysis approach to study the molecular structure of Cvt vesicles. We report the oligomeric nature of the major Cvt cargo Ape1 with a combined 2.8 Å X‐ray and negative stain EM structure, as well as the secondary cargo Ams1 with a 6.3 Å cryo‐EM structure. We show that the major dodecameric cargo prApe1 exhibits a tendency to form higher‐order chain structures that are broken upon interaction with the receptor Atg19 in vitro. The stoichiometry of these cargo–receptor complexes is key to maintaining the size of the Cvt aggregate in vivo. Using correlative light and electron microscopy, we further visualize key stages of Cvt vesicle biogenesis. Our findings suggest that Atg19 interaction limits Ape1 aggregate size while serving as a vehicle for vacuolar delivery of tetrameric Ams1.     

Prospects for estimating nucleotide divergence with RAPDs

The technique of random amplification of polymorphic DNA (RAPD), which is simply polymerase chain reaction (PCR) amplification of genomic DNA by a single short oligonucleotide primer, produces complex patterns of anonymous polymorphic DNA fragments. The information provided by these banding patterns has proved to be of great utility for mapping and for verification of identity of bacterial strains. Here we consider whether the degree of similarity of the banding patterns can be used to estimate nucleotide diversity and nucleotide divergence. With haploid data, fragments generated by RAPD-PCR can be treated in a fashion very similar to that for restriction-fragment data. Amplification of diploid samples, on the other hand, requires consideration of the fact that presence of a band is dominant to absence of the band. After describing a method for estimating nucleotide divergence on the basis of diploid samples, we summarize the restrictions and criteria that must be met when RAPD data are used for estimating population genetic parameters.      

Chromium intake and urinary chromium excretion of trauma patients

Glucose metabolism is altered after trauma and those factors that affect glucose metabolism often affect chromium (Cr) metabolism and excretion. To ascertain whether urinary Cr excretion is affected by the elevated serum glucose and other factors associated with trauma, the serum glucose and urinary Cr and Creatinine (Cre) excretion of seven severely traumatized patients were determined. The Cr concentration of intravenous (IV) fluids administered was determined and approximate Cr intake calculated. For all patients, urinary Cr concentration was high in the initial sample collected within 24 h of admission (10.3 ± 2.5 ng/mL, mean ± SEM) and decreased significantly (P < 0.05) by 42 h (2.0 ±0.6 ng/mL). The mean urinary Cr concentration 42 h following admission was 10 times greater than the urinary Cr concentration of normal, healthy subjects (0.2 ± 0.02 ng/mL). There was no significant change in urinary Cre concentration within 42 h of admission, therefore the ratio of urinary Cr to Cre (ng Cr:mg Cre) also decreased. Serum glucose concentration was elevated at admission (170 ± 18 mg/dL, mean ± SD) and decreased to 145 ± 10 mg/dL by 48 h post-admission. The intravenous fluids, dextrose and NaCl, were the lowest in Cr of the samples tested, range 0.02 to 0.20 ng/mL; lactated Ringer’s solution, with or without dextrose, contained 10-20 times more Cr and plasma protein fraction contained approximately 32 ng/mL. The mean calculated Cr intake for the first 24 h postadmission was 37.1 µg/d, significantly greater (P < 0.01) than intake from 24 to 48 h (0.12 µg/d) and 48-72 h (1.63 µg/d). The IV intake of Cr varied for trauma patients depending on fluids required during treatment, but for all patients the relatively high IV Cr intake was rapidly excreted in the urine. These data demonstrate that urinary Cr concentration is elevated several-fold within 24 h of trauma and that Cr contents of intravenous fluids administered in the days immediately following injury vary dramatically. The effects of trauma alone on Cr excretion are difficult to assess because of the variable intake of Cr from IV fluids.     

Loss of carrier-determined tolerance in vitro with loss of receptor blockade.

Experiments were done to determine whether carrier-determined tolerance is reversible and whether the loss of tolerance is accompanied by the loss of receptor blockade. Spleen cells from mice made tolerant with DNP-isologous IgG remained tolerant when transferred to irradiated syngeneic mice. If these same tolerant spleen cells were incubated for 24 hr or more before transfer the tolerance was lost. Autoradiology was done on the tolerant cells with either 125I anti-DNP or 125DNP-KLH, before and after incubation in vitro. When the cells were tolerant the number of DNP ABC was decreased whereas cells having DNP on their surface were increased. When the cells lost tolerance after in vitro incubation, the hapten-bearing cells were no longer present although the number of cells free DNP receptors increased to normal. These data suggest that in carrier determined tolerance the reactivation of tolerant lymphocytes may involve reversible receptor blockade.     

Deciphering Cell Lineage Specification during Male Sex Determination with Single-Cell RNA Sequencing

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