Factors Predicting Prolonged Mechanical Ventilation in Guillain-Barré Syndrome.

BACKGROUND: Up to 30% of patients with Guillain-Barré syndrome require mechanical ventilation and 5% die due to acute complications of mechanical ventilation. There is a considerable group of patients that will need prolonged mechanical ventilation (considered as >14 days) and should be considered for early tracheostomy. The objective of this study is to identify risk factors for prolonged mechanical ventilation. METHODS: We prospectively analyzed patients with Guillain-Barré diagnosis with versus without prolonged mechanical ventilation. We considered clinical and electrophysiological characteristics and analyzed factors associated with prolonged mechanical ventilation. RESULTS: Three hundred and three patients were included; 29% required mechanical ventilation. When comparing the groups, patients with prolonged invasive mechanical ventilation (IMV) have a lower score on the Medical Research Council score (19.5 ± 16.2 vs 27.4 ± 17.5, p = 0.03) and a higher frequency of dysautonomia (42.3% vs 19.4%, p = 0.037), as well as lower amplitudes of the distal compound muscle action potential (CMAP) of the median nerve [0.37 (RIQ 0.07-2.25) vs. 3.9 (RIQ1.2-6.4), p = <0.001] and ulnar nerve [0.37 (RIQ0.0-3.72) vs 1.5 (RIQ0.3-6.6), p = <0.001], and higher frequency of severe axonal damage in these nerves (distal CMAP ≤ 1.0 mV). Through binary logistic regression, severe axonal degeneration of the median nerve is an independent risk factor for prolonged IMV OR 4.9 (95%CI 1.1-21.5) p = 0.03, AUC of 0.774, (95%CI 0.66-0.88), p = < 0.001. CONCLUSIONS: Severe median nerve damage is an independent risk factor for prolonged mechanical ventilation.

Effect of calcium soaps from garlic (Allium sativum) and willow (Salix babylonica) extracts on nematode loads, nutrient intake and digestibility, nitrogen balance and rumen fermentation kinetics in dairy goats.

The objective of this study was to determine the effect of dietary calcium soaps from garlic (Allium sativum) and willow (Salix babylonica) extracts on nematode loads, nutrient intake and digestibility, nitrogen balance and rumen fermentation kinetics in dairy goats. Nine adult non-lactating Saanen goats were grouped into a complete randomized block design with 3 treatments (n = 3) over a period of 28 d. Animals were fed a diet based on alfalfa hay and a concentrate that was supplemented (65 g/kg DM) with calcium soaps of safflower (control), garlic or willow. Intake of dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) were not affected by dietary calcium soaps. However, the highest digestibility of DM and OM were observed in willow supplemented goats. In vitro gas kinetics and fermentation profile were not affected by diets. Results from fecal egg count indicated a reduction in total count, Haemonchus spp. and Trychostrongylus spp. for both garlic and willow compared to control. Our results suggest that calcium soaps of garlic or willow extracts can be used to reduce gastrointestinal parasites in goats without compromising productive traits or rumen function.

Prognostic Implications of Early Albuminocytological Dissociation in Guillain-Barré Syndrome.

BACKGROUND: Half of Guillain-Barré syndrome (GBS) present elevated cerebrospinal fluid (CSF) protein levels within 1 week since symptom onset and 80% within 2 weeks. Our objective was to determine the clinical and prognostic implication of albuminocytological dissociation in early GBS. METHODS: An ambispective cohort study was conducted. Good outcome was considered if the patient was able to walk unaided (Guillain-Barré disability score [GDS] ≤ 2 points) at 3-month follow-up. Patients were classified into two groups: with and without albuminocytological dissociation; we compared clinical and paraclinic characteristics between the groups. We analyzed clinical and electrophysiological factors related to presenting early dissociation through a multivariate model. RESULTS: We included 240 patients who fulfilled Asbury criteria for GBS. On further selection, only 94 patients fulfilled inclusion. Mean age was 45.94 ± 17.1 years and 67% were male. Median time from symptom onset to admission was 5 days (IQR 3-6). Regarding albuminocytological dissociation and electrophysiological variants, we found a significant difference: acute inflammatory demyelinating polyneuropathy (AIDP) [60.6% vs 26.2%, p = 0.002], acute motor axonal neuropathy (AMAN) [21.2% vs 49.1%, p = 0.009] and acute motor sensory axonal neuropathy (AMSAN) [12.1% vs 1.6%, p = 0.05]. We did not observe significant differences in recovery of independent walking in short term between both groups. The presence of conduction block in any variant (OR 3.21, 95% CI 1.12-9.16, p = 0.02) and absence of sural registration (OR 5.69, 95% CI 1.48-21.83, p = 0.011) were independent factors related to early dissociation. CONCLUSIONS: Early dissociation (<7 days) is not associated with any particular clinical feature or unfavorable outcome. It is more common to see in AIDP rather than axonal variants.

Association between muscle quality index and pulmonary function in post-COVID-19 subjects.

BACKGROUND: The SARS-CoV2 pandemic impacted many critically ill patients, causing sequelae, affecting lung function, and involving the musculoskeletal system. We evaluated the association between lung function and muscle quality index in severely ill post-COVID-19 patients. METHODS: A cross-sectional study was conducted on a post-COVID-19 cohort at a third-level center. The study included patients who had experienced severe-to-critical COVID-19. Anthropometric measurements, such as body mass index (BMI) and handgrip strength, were obtained to calculate the muscle quality index (MQI). Additionally, spirometry, measurements of expiratory and inspiratory pressure, and an assessment of DLCO in the lungs were performed. The MQI was categorized into two groups: low-MQI (below the 50th percentile) and high-MQI (above the 50th percentile), based on sex. Group differences were analyzed, and a multivariate linear regression analysis was performed to assess the association between respiratory function and MQI. RESULTS: Among the 748 patients analyzed, 61.96% required mechanical ventilation, and the median hospital stay was 17 days. In patients with a low MQI, it was observed that both mechanical respiratory function and DLCO were lower. The multivariate analysis revealed significantly lower findings in mechanical respiratory function among patients with a low MQI. CONCLUSION: The Low-MQI is an independent predictor associated with pulmonary function parameters in subjects with Post-COVID-19 syndrome.

Comparative analysis of ß-glucosidase activity in non-conventional yeasts.

The objective of this study was to evaluate the ß-glucosidase activity in the non-conventional yeasts under cellulose, glucose and sucrose substrates. The participation of the enzyme ß-glucosidase and its contribution to the enzymatic degradation of tannins is known. Within the classification of tannins are ellagitannins, molecules of gallic acid and ellagic acid, which are considered as nutraceutical compounds due to the properties that they present and that they can be used in the design of food and new drugs, synthesis of materials with antimicrobial capacity. The extracellular ß-glucosidase activity was mainly presented in the Candida and Pichia strains, being the glucose and sucrose media the most capable for inducing the activity that showed maximum values with P. pastoris in glucose (0.1682±0.00 µmol/min mg protein), and C. utilis in cellulose (0.1129±0.1349 µmol/min mg of protein), and sucrose (0.0657±0.0214 µmol/min mg protein). Additionally, I. terricola and P. kluyvery stood out in a qualitative cellulose degradation approach measured by Congo red method (9.60±0.04 mm and 9.20±0.05 mm respectively). These indicate that P. pastoris and C. utilis have potential as ß-glucosidase producers, especially when growing under complex carbon sources for biomass conversion, new biofuels production and polyphenol degradation with more manageable bioreactor process.

Obtaining polyphenolic extracts from pomegranate peel (Punica granatum) to evaluate the bactericide and antioxidant activity.

Pomegranate (Punica granatum) contains secondary metabolites with antioxidant and bactericide activity; however, the study of the peel in the endemic varieties of Mexico has not been deepened. The polyphenols extraction of peel pomegranate endemic to the state of Michoacan, Mexico could be used in the formlulation of healthy food due contains antioxidant compounds or could be used like drugs due contains antibactericide compunds.In this work 3 varieties of pomegranate were analyzed; Wonderful, Apaseo and Tecozautla harvested in 2017 and 2018, carrying out a physicochemical characterization to establish the ripening, application of an experimental design of response surface for drying the peel and extracting polyphenols using two solvents (acetone and ethanol) by the Soxhlet method. As a result, the pomegranates were in the correct ripening, in the drying an optimal point of operation was found without affecting the metabolites (36 h at 55 °C) and in the extraction, the bactericide and antioxidant activity was evaluated observing that in the ketone extracts the best results were obtained in the Apaseo variety being; ABTS•+ technique of 150.78 ET mM/g, DPPH• 109.8 ET mM/g and 11.82 EAG mg/g in dry extract. For the bactericide activity measured by inhibition halos in S. aureus and E. coli it was had; 20.03 mm and 14.05 mm respectively for the Apaseo variety, which is why it is convenient to extract polyphenols under this method in peel of Mexican pomegranate varieties.

Deltoid muscle strength and autonomic dysfunction as independent risk factors for invasive mechanical ventilation in patients with Guillain-Barré syndrome.

BACKGROUND: Almost a third of patients with Guillain-Barré Syndrome (GBS) require mechanical ventilation, increasing mortality by 15-30% and proving poor functional outcomes. The Erasmus GBS Respiratory Insufficiency Score (EGRIS) is the most frequently used scale to assess probability of respiratory insufficiency within the first week of admission. We aim to determine other clinical and electrophysiological prognostic factors for invasive mechanical ventilation (IMV) in patients with GBS. MATERIAL AND METHODS: A cross-sectional ambispective cohort study was carried out in a referral center in Mexico City, from January 2015 to December 2019. Baseline demographics, MRC score, Hughes scale, EGRIS, dysautonomia and nerve conduction studies were performed on admission in GBS patients that required IMV. A multivariable analysis for IMV and a survival analysis for independent walk in prolonged-IMV (>14 days) were performed. RESULTS: Forty-nine (32%) out of 153 GBS patients required IMV. Statistically significant prognostic factors in multivariable analysis were deltoid muscle strength ≤2 [OR 7.1 (1.6-31.1)], EGRIS [OR 2.5 (1.3-4.6)] and autonomic dysfunction [OR 6.6 (2.0-22.0)]. Electrodecrement <1 mV in the compound muscle action potential (CMAP) of distal motor median nerve was more prevalent in prolonged-IMV patients (44.8% vs. 21%, p = .049). A significant minor prevalence of prolonged-IMV patients regain independent walk at 6 months using the Kaplan-Meier method (log rank test p < .001). CONCLUSIONS: We provide new specific clinical (deltoid muscle strength and autonomic dysfunction) and electrophysiological variables to discriminate GBS patients that will require IMV.

Potential Hypoglycemic and Antilipidemic Activity of Polyphenols from Passiflora ligularis (Granadilla).

The consumption of fruits or by-products from plants of the Passifloraceae family has been associated with multiple health and nutritional benefits, due to their phenolic compound content. Likewise, the effects of polyphenols from Camellia sinensis (green tea) have been explored and are considered a reference for different biological actions of these bioactive substances. This study compared the hypoglycemic and antilipemic activity of polyphenol-rich extracts of Passiflora ligularis Juss (passion fruit) and Camellia sinensis (green tea) given to a group of Wistar rats induced to be overweight. The individuals were subjected to three doses of supplementation of both sources of polyphenols in the drinking water. An additional group without polyphenol supplementation served as a control group. Water consumption, weight gain, glycemia, cholesterol, serum triglycerides and percentage of fecal ethereal extracts were analyzed. Although Passiflora ligularis Juss had five times less polyphenol content than Camellia sinensis, rats fed doses of 2.5 and 3.0 g/L Passiflora ligularis Juss showed reduced glycemia by 16%, suggesting an antiglycemic activity similar to that of Camellia sinensis. On the other hand, higher doses of polyphenols from Passiflora ligularis Juss and Camellia sinensis significantly reduced triglyceride levels (p = 0.05) by more than 17% compared to the unsupplemented control group. The polyphenol-rich extracts produced effective inhibitory activity of lipemic metabolites with a reduction in the percentage of fecal lipids (p < 0.05), with no side effects on liver tissue. The 3.0 g/L dose produced the best result on signs of metabolic syndrome associated with excess weight. Polyphenols extracted from fresh Colombian passion fruit showed the potential to decrease metabolic syndrome risk factors in a murine model.

Effectiveness of spontaneous pain coping strategies for acute pain management: A laboratory study.

The aim of the present study has been to analyze the relationship between the use of not previously trained, diverse acute pain coping strategies and levels of pain intensity and pain tolerance in a group of healthy participants. Previous research has analyzed the usefulness of the training of these strategies after several training sessions, but adequate patient training requires a great deal of time. Two hundred and forty healthy people participated in the study. Pain coping strategies was evaluated with a version of CSQ-S. Subsequently, the participants completed a cold pressor test and tolerance test. After that, subjects filled in the adaptation of the CSQ-S about the strategies which they had employed throughout the test. Correlation analyses showed a positive relationship between pain intensity and catastrophizing, distractor behaviors, hoping and ignoring the pain. Pain tolerance correlated with self-instructions, ignoring the pain, reinterpreting the pain, catastrophizing and faith and praying. Regression analyses showed that catastrophizing was found to be the strategy that most predicts the variance of pain intensity, and catastrophizing (negative) and ignoring the pain (positive) and praying (negative) were the most predictive ones for pain tolerance. This is the first laboratory study that identifies the more useful pain coping strategies which can be used by patients without previous training in an acute pain context. The results of this study could be useful in the development of protocols for nurses and other health professionals, especially for situations where potentially painful techniques are to be applied to patients.

Snf1p/Hxk2p/Mig1p pathway regulates hexose transporters transcript levels, affecting the exponential growth and mitochondrial respiration of Saccharomyces cerevisiae.

The Crabtree effect molecular regulation comprehension could help to improve ethanol production with biotechnological purposes and a better understanding of cancer etiology due to its similarity with the Warburg effect. Snf1p/Hxk2p/Mig1p pathway has been linked with the transcriptional regulation of the hexose transporters and phenotypes associated with the Crabtree effect. Nevertheless, direct evidence linking the genetic control of the hexose transporters with modulation of the Crabtree effect phenotypes by the Snf1p/Hxk2p/Mig1p pathway is still lacking. In this sense, we provide evidence that SNF1 and HXK2 genes deletion affects exponential growth, mitochondrial respiration, and transcript levels of hexose transporters in a glucose-dependent manner. The Vmax of the hexose transporters with the high transcript levels was correlated positively with the exponential growth and negatively with the mitochondrial respiration. HXT2 gene transcript levels were the most affected by the deletion of the SNF1/HXK2/MIG1 pathway. Deleting the orthologous genes SNF1 and HXK2 in Kluyveromyces marxianus (Crabtree negative yeast) has an opposite effect compared to Saccharomyces cerevisiae in growth and mitochondrial respiration. Overall, these results indicate that the SNF1/HXK2/MIG1 pathway regulates transcript levels of the hexose transporters, which shows an association with the exponential growth and mitochondrial respiration in a glucose-dependent manner.

Cytotoxicity of quercetin is related to mitochondrial respiration impairment in Saccharomyces cerevisiae.

Quercetin is a flavonol ubiquitously present in fruits and vegetables that shows a potential therapeutic use in non-transmissible chronic diseases, such as cancer and diabetes. Although this phytochemical has shown promising health benefits, the molecular mechanism behind this compound is still unclear. Interestingly, quercetin displays toxic properties against phylogenetically distant organisms such as bacteria and eukaryotic cells, suggesting that its molecular target resides on a highly conserved pathway. The cytotoxicity of quercetin could be explained by energy depletion occasioned by mitochondrial respiration impairment and its concomitant pleiotropic effect. Thereby, the molecular basis of quercetin cytotoxicity could shed light on potential molecular mechanisms associated with its health benefits. Nonetheless, the evidence supporting this hypothesis is still lacking. Thus, this study aimed to evaluate whether quercetin supplementation affects mitochondrial respiration and whether this is related to quercetin cytotoxicity. Saccharomyces cerevisiae was used as a study model to assess the effect of quercetin on energetic metabolism. Herein, we provide evidence that quercetin supplementation: (1) decreased the exponential growth of S. cerevisiae in a glucose-dependent manner; (2) affected diauxic growth in a similar way to antimycin A (complex III inhibitor of electron transport chain); (3) suppressed the growth of S. cerevisiae cultures supplemented with non-fermentable carbon sources (glycerol and lactate); (4) promoted a glucose-dependent inhibition of the basal, maximal, and ATP-linked respiration; (5) diminished complex II and IV activities. Altogether, these data indicate that quercetin disturbs mitochondrial respiration between the ubiquinone pool and cytochrome c, and this phenotype is associated with its cytotoxic properties.

Clinical and genetic features of a large homogeneous cohort of oculopharyngeal muscular dystrophy patients from the Canary Islands.

BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant, late-onset myopathy characterized by ptosis, dysphagia, and progressive proximal limb muscle weakness. The disease is produced by a short expansion of the (GCN)n triplet in the PABPN1 gene. The size of expansion has been correlated to the disease onset and severity. We report the clinical features of a large cohort of OPMD patients harboring the (GCN)15 allele from the Canary Islands. METHODS: A retrospective observational study was performed analyzing the clinical, demographic, and genetic data of 123 OPMD patients. Clinical data from this cohort were compared with clinical data collected in a large European study including 139 OPMD patients. RESULTS: A total of 113 patients (94.2%) carried the (GCN)15 expanded PABN1 allele. Age of symptoms' onset was 45.1 years. The most frequent symptom at onset was ptosis (85.2%) followed by dysphagia (12%). The severity of the disease was milder in the Canary cohort compared to European patients as limb weakness (35.1% vs. 50.4%), the proportion of patients that require assistance for walking or use a wheelchair (9.3% vs. 27.4%), and needed of surgery because of severe dysphagia (4.6% vs. 22.8%) was higher in the European cohort. CONCLUSIONS: Nearly 95% of patients with OPMD from the Canary Islands harbored the (GCN)15 expanded allele supporting a potential founder effect. Disease progression seemed to be milder in the (GCN)15 OPMD Canary cohort than in other cohorts with shorter expansions suggesting that other factors, apart from the expansion size, could be involved in the progression of the disease.

Safety and efficacy of convalescent plasma for severe COVID-19: a randomized, single blinded, parallel, controlled clinical study.

BACKGROUND: Convalescent plasma (CP) has been widely used to treat COVID-19 and is under study. However, the variability in the current clinical trials has averted its wide use in the current pandemic. We aimed to evaluate the safety and efficacy of CP in severe coronavirus disease 2019 (COVID-19) in the early stages of the disease. METHODS: A randomized controlled clinical study was conducted on 101 patients admitted to the hospital with confirmed severe COVID-19. Most participants had less than 14 days from symptoms onset and less than seven days from hospitalization. Fifty patients were assigned to receive CP plus standard therapy (ST), and 51 were assigned to receive ST alone. Participants in the CP arm received two doses of 250 mL each, transfused 24 h apart. All transfused plasma was obtained from "super donors" that fulfilled the following criteria: titers of anti-SARS-CoV-2 S1 IgG ≥ 1:3200 and IgA ≥ 1:800 antibodies. The effect of transfused anti-IFN antibodies and the SARS-CoV-2 variants at the entry of the study on the overall CP efficacy was evaluated. The primary outcomes were the reduction in viral load and the increase in IgG and IgA antibodies at 28 days of follow-up. The per-protocol analysis included 91 patients. RESULTS: An early but transient increase in IgG anti-S1-SARS-CoV-2 antibody levels at day 4 post-transfusion was observed (Estimated difference [ED], - 1.36; 95% CI, - 2.33 to - 0.39; P = 0.04). However, CP was not associated with viral load reduction in any of the points evaluated. Analysis of secondary outcomes revealed that those patients in the CP arm disclosed a shorter time to discharge (ED adjusted for mortality, 3.1 days; 95% CI, 0.20 to 5.94; P = 0.0361) or a reduction of 2 points on the WHO scale when compared with the ST group (HR adjusted for mortality, 1.6; 95% CI, 1.03 to 2.5; P = 0.0376). There were no benefits from CP on the rates of intensive care unit admission (HR, 0.82; 95% CI, 0.35 to 1.9; P = 0.6399), mechanical ventilation (HR, 0.66; 95% CI, 0.25 to 1.7; P = 0.4039), or mortality (HR, 3.2; 95% CI, 0.64 to 16; P = 0.1584). Anti-IFN antibodies and SARS-CoV-2 variants did not influence these results. CONCLUSION: CP was not associated with viral load reduction, despite the early increase in IgG anti-SARS-CoV-2 antibodies. However, CP is safe and could be a therapeutic option to reduce the hospital length of stay. Trial registration NCT04332835.

Very low peroneal nerve compound muscle action potential amplitude predicts poor outcome in patients with Guillain-Barré syndrome: a prospective cohort.

INTRODUCTION: Twenty percent of patients with Guillain-Barré syndrome (GBS) have poor outcomes despite proper management. The aim of the study was to characterize electrophysiological factors related to poor outcome in patients with GBS. METHODS: We conducted an observational study from a prospective cohort of 91 patients with GBS in a tertiary healthcare center in Mexico, from 2017 to 2019. Demographics and nerve conduction studies were performed on admission, and a 3-month follow-up for GBS disability score was ensued, allocating patients in good (GBS disability score ≤ 2) and poor outcome (GBS disability score ≥ 3) groups. A logistic regression analysis for independent walk at 3 months was performed. Kaplan-Meier estimator curves for independent walk in very low (< 20% LLN) and low-normal ( ≥20% LLN) peroneal nerve CMAPs are presented. RESULTS: From the 91 GBS patients included, 37 (40.6%) did not regain independent walk at 3 months. Axonal variants were more common in the poor outcome group (31.4% vs 59.4%, p = 0.01) as well as AIDP variants with motor conduction block (6.6% vs 42.4%, p = 0.018). Univariable analysis was statistically significant for very low median, ulnar, tibial, and peroneal CMAP amplitudes in poor outcome patients; however, multivariable analysis was only significant for very low peroneal nerve CMAP amplitude (OR 3.6 [1.1-11.5, p = 0.024]). Conversely, a greater proportion of GBS patients with low-normal CMAPs recovered independent walk at 90 days (75% vs 30%, p < 0.001). CONCLUSION: Severe axonal injury of the peroneal nerve, axonal, and AIDP with motor conduction block variants predicts worse functional outcome regarding independent walk at 3 months.

Effect of B-NIPOx in Experimental Trypanosoma cruzi Infection in Mice.

Chagas disease is caused by Trypanosoma cruzi and represents a major public health problem, which is endemic in Latin America and emerging in the rest of the world. The two drugs that are currently available for its treatment, Benznidazole and Nifurtimox, are partially effective in the chronic phase of the disease. In this study, we designed and synthesized the benzyl ester of N-isopropyl oxamic acid (B-NIPOx), which is a non-polar molecule that crosses cell membranes. B-NIPOx is cleaved inside the parasite by carboxylesterases, releasing benzyl alcohol (a molecule with antimicrobial activity), and NIPOx, which is an inhibitor of α-hydroxy acid dehydrogenase isozyme II (HADH-II), a key enzyme in T. cruzi metabolism. We evaluated B-NIPOx cytotoxicity, its toxicity in mice, and its inhibitory activity on purified HADH-II and on T. cruzi homogenates. We then evaluated the trypanocidal activity of B-NIPOx in vitro and in vivo and its effect in the intestine of T. cruzi-infected mice. We found that B-NIPOx had higher trypanocidal activity on epimastigotes and trypomastigotes than Benznidazole and Nifurtimox, that it was more effective to reduce blood parasitemia and amastigote nests in infected mice, and that, in contrast to the reference drugs, it prevented the development of Chagasic enteropathy.

Antioxidant Activity of Polyphenols, from Mauritia flexuosa (Aguaje), Based on Controlled Dehydration.

Plant polyphenols offer several benefits for the prevention of diverse illnesses. Fruit's edible and inedible parts (pulp, seeds, peels, stems, flowers) are important sources of polyphenols. Different industrial processes for fruit treatment and commercialization affect the total polyphenol content (TPC), and probably the biological activity. The purpose of the present work was to determine the TPC and antioxidant activity (by DPPH) of polyphenols extracted from the pulp and seeds of Mauritia flexuosa (aguaje), in fresh and dehydrated forms, in order to determine the possible connection with the quantity of polyphenols and their specific antioxidant activity. The highest phenolic content for M. flexuosa seeds in fresh form (non-dehydrated) was 270.75 mg GAE/100 g with a 96-h extraction. With respect to the dehydrated samples, the best yield was quantified in the 96-h dehydrated seed sample. For all pulp and seeds, dehydrated for 24, 48, and 96 h, TPC showed a slightly decreasing pattern. The DPPH results were the highest in the 96-h dehydrated samples and the differences among all dehydrated pulp and seed samples were minimal. More studies testing the presence of other antioxidant components could help in understanding the detailed antioxidant activity, and related more to the specific action, rather than only total polyphenol content.

Antioxidant Activity and Kinetic Characterization of Chlorella vulgaris Growth under Flask-Level Photoheterotrophic Growth Conditions.

C. vulgaris is a unicellular microalgae, whose growth depends on the conditions in which it is found, synthesizing primary and secondary metabolites in different proportions. Therefore, we analyzed and established conditions in which it was possible to increase the yields of metabolites obtained at the flask level, which could then be scaled to the photobioreactor level. As a methodology, a screening design was applied, which evaluated three factors: type of substrate (sodium acetate or glycerol); substrate concentration; and exposure-time to red light (photoperiod: 16:8 and 8:16 light/darkness). The response variables were: cell division; biomass; substrate consumption; and antioxidant activity in intracellular metabolites (ABTS•+ and DPPH•). As a result, the sodium acetate condition of 0.001 g/L, in a photoperiod of 16 h of light, presented a doubling time (Td = 4.84 h) and a higher rate of division (σ = 0.20 h-1), having a final biomass concentration of 2.075 g/L. In addition, a higher concentration of metabolites with antioxidant activity was found in the sodium acetate (0.629 Trolox equivalents mg/L ABTS•+ and 0.630 Trolox equivalents mg/L DPPH•). For the glycerol, after the same photoperiod (16 h of light and 8 h of darkness), the doubling time (Td) was 4.63 h, with a maximum division rate of σ = 0.18 h-1 and with a biomass concentration at the end of the kinetics of 1.4 g/L. Sodium acetate under long photoperiods, therefore, is ideal for the growth of C. vulgaris, which can then be scaled to the photobioreactor level.

Effect of soybean grain (Glycine max L.) supplementation on the production and fatty acid profile in milk of grazing cows in the dry tropics of Mexico.

Improving the lipid profile in milk of cows with the use of soybean grain (Glycine max L.) can be favored in the grazing systems in the dry tropics of Mexico. The objective was to evaluate the milk production, the chemical composition, and the fatty acids profile (FAs) of the milk of cows in continuous grazing and supplemented with and without ground roasted soybean in the dry tropics of Mexico. Ten cows randomly distributed in two equal groups were used. Daily during confinement for milking, the cows individually received the treatments on dry basis T0: supplement with 4.6 kg commercial concentrate® without soybean, T1: supplement with 3.7 kg commercial concentrate® with 380 g of soybean. During the 78 days of the experiment, milk production was measured in all cows, and samples were collected to determine the chemical composition and FAs profile. Milk production, protein, milk total fat, lactose, and non-fat solids did not vary with treatment (p >0.05). Linoleic acid content (C18: 2, cis, cis-∆9, ∆12) increased by 22% in milk fat of cows of the T1 (p ˂0.05). The sum of the mono- and polyunsaturated FAs 29.1%, the ratio of saturated-unsaturated FAs (1.65), and the atherogenicity index (1.71) also improved in the milk of cows supplemented with T1 (p ˂0.05). It was concluded that ground roasted soybean supplement in the diet of grazing dairy cows did not affect production and did improve the lipid profile in milk fat with favorable index to promote human health.

The economic effects of grazing in small-scale lamb fattening production systems in central México through a scenario analysis.

The objective was to assess grazing as an element of profitability and competitiveness of a small-scale lamb fattening production system in central México and compare its economic performance by means of an analysis of scenarios. Two scenarios were analysed to assess the contribution of grazing on profitability and competitiveness. The first analysis was when grazing was the feed base, and secondly, costs of opportunity and economic impacts were studied under the assumption that sheep do not graze, and total feed has to be bought from external suppliers. The economic effect of grazing on the profitability was analysed by means of the Policy Analysis Matrix. Differences were found between strata; farmers with more than 70 sheep have the best profitability indices and the least vulnerability under the non-grazing scenario. Grazing had a positive effect reducing the cost of production and increasing competitiveness in the four strata assessed. However, farmers with higher technical level, specialised breeds and larger flocks (strata 3 and 4) have higher economic profits. The conclusion was that the profitability in fattening sheep is linked to taking advantage of grazing. However, to keep and improve the current financial performance, there is a need for the adoption of strategies for an integral improvement of the system and the adoption of better grazing management to further reduce production costs.

Sexual Behaviors and Factors Associated with Condomless Sexual Practice in Colombian Men Who Have Sex with Men at High Risk of HIV Transmission.

Men who have sex with men (MSM) have a disproportionate burden of HIV infection worldwide. In Colombia, the prevalence of HIV in MSM is ~ 43 times higher than in the general population (17% vs. 0.4%). This study determined the sexual behaviors, HIV serostatus, and associated factors with condomless sexual practice with both regular and casual partners in 92 MSM from Medellín, Colombia. The subjects were recruited through a community-based approach, and the data were collected by a structured survey and in-depth interviews. Participants were classified into three groups according to the number of sexual partners in the last three months, to compare the sociodemographic conditions and sexual behaviors. Univariate analysis was described by absolute and relative frequencies; bivariate analysis and multivariate logistic regression were used to compare the groups and to explore the associated factors with condomless sexual practice. The overall HIV estimated prevalence was 4.3%, while the estimated prevalence for MSM with > 10 sexual partners in the last three months was 14.8%. This last group showed higher average age, higher percentage of subjects who have had sex with people living with HIV, and increased frequency of previous sexually transmitted infections. Having condomless sex with casual partners was associated with the number of sexual partners in the last three months. This study demonstrates that Colombian MSM continue to have a high risk of HIV infection/transmission and reinforce the need to implement adequate prevention programs, PrEP and guarantee access to treatment for people living with HIV.