Development of a magnetically stabilized fluidized bed bioreactor for enzymatic synthesis of 2-ethylhexyl oleate.

This study aimed to develop and investigate the synthesis of 2-ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on magnetic poly(styrene-co-divinylbenzene) (STY-DVB-M) particles in a magnetically stabilized fluidized bed reactor (MSFBR) operated in continuous mode. The physical properties of the copolymer were characterized by Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The glass transition temperature was 85.68 °C, and the onset of thermal degradation occurred at 406.66 °C. Syntheses were performed at 50 °C using a space time of 12 h and a bed porosity of 0.892. Assays were conducted to assess the influence of magnetic field intensity (5 to 15 mT) on reaction yield, ester concentration, and productivity. The highest productivity was 0.850 ± 0.023 mmol g-1 h-1, obtained with a magnetic field intensity of 15 mT. An operational stability test was performed under these conditions, revealing a biocatalyst half-life of 2148 h (179 operation cycles) and a thermal deactivation constant of 3.23 × 10-4 h-1 (R2 = 0.9446). Computational simulations and mathematical modeling were performed using Scilab based on ping-pong bi-bi kinetics and molar balances of reaction species. The model provided consistent results of interstitial velocity and good prediction of reaction yields, with R2 = 0.926. These findings demonstrate that the studied technique can provide improvements in biocatalytic processes, representing a promising strategy for the enzymatic synthesis of 2-ethylhexyl oleate.

Comparing CPAP masks during initial titration for Obstructive Sleep Apnea Syndrome: one-year experience

Abstract Objective: Continuous Positive Airway Pressure (CPAP) is the gold standard treatment for OSA. A wide variety of masks are used during CPAP therapy. The aim of the study is to compare polysomnography outcomes during titration for different types of masks (oronasal, nasal and pillow) and assess the impact on PAP titration. Methods: We retrospectively analyzed all CPAP titration polysomnography for one year. Anthropometric data and baseline apnea severity were documented. Results: A total of 497 patients were evaluated. Nasal masks were used in 82.3% (n = 409), pillow in 14.1% (n = 70) and oronasal in 3.6% (n = 18). There was no difference according to body mass index and baseline apnea-hypopnea index among the groups. The oronasal group was older and had higher titrated CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency, more superficial N1 sleep and longer wake time after sleep onset. All other polysomnography outcomes were similar among the groups. The mean CPAP level was 11.6 ± 2.1 cm H2O for the oronasal mask, 10.1 ± 2.1 cm H2O for the nasal mask and 9.8 ± 2.2 cm H2O for the pillow. The residual apnea-hypopnea index was 10.4 ± 7.9 for the oronasal mask, 5.49 ± 5.34 events/h for the nasal mask and 4.98 ± 5.48 events/h for the pillow. The baseline apnea-hypopnea index was correlated with of a higher CPAP pressure for all the groups (p< 0.001 for the nasal group, p = 0.001 for the pillow group and p = 0.049 for the oronasal group). Body mass index and residual AHI were correlated with of a higher CPAP pressure for the nasal and pillow groups only (p < 0.001). Conclusion: The interface can have a significant impact on the effectiveness of PAP titration. Patients with oronasal masks have higher CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency and higher wake time after sleep onset. Oronasal masks should not be recommended as the first choice for apnea patients. Level of evidence: Level 3.

Comparing CPAP masks during initial titration for Obstructive Sleep Apnea Syndrome: one-year experience.

OBJECTIVE: Continuous Positive Airway Pressure (CPAP) is the gold standard treatment for OSA. A wide variety of masks are used during CPAP therapy. The aim of the study is to compare polysomnography outcomes during titration for different types of masks (oronasal, nasal and pillow) and assess the impact on PAP titration. METHODS: We retrospectively analyzed all CPAP titration polysomnography for one year. Anthropometric data and baseline apnea severity were documented. RESULTS: A total of 497 patients were evaluated. Nasal masks were used in 82.3% (n = 409), pillow in 14.1% (n = 70) and oronasal in 3.6% (n = 18). There was no difference according to body mass index and baseline apnea-hypopnea index among the groups. The oronasal group was older and had higher titrated CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency, more superficial N1 sleep and longer wake time after sleep onset. All other polysomnography outcomes were similar among the groups. The mean CPAP level was 11.6 ±â€¯2.1 cm H2O for the oronasal mask, 10.1 ±â€¯2.1 cm H2O for the nasal mask and 9.8 ±â€¯2.2 cm H2O for the pillow. The residual apnea-hypopnea index was 10.4 ±â€¯7.9 for the oronasal mask, 5.49 ±â€¯5.34 events/h for the nasal mask and 4.98 ±â€¯5.48 events/h for the pillow. The baseline apnea-hypopnea index was correlated with of a higher CPAP pressure for all the groups (p < 0.001 for the nasal group, p = 0.001 for the pillow group and p = 0.049 for the oronasal group). Body mass index and residual AHI were correlated with of a higher CPAP pressure for the nasal and pillow groups only (p < 0.001). CONCLUSION: The interface can have a significant impact on the effectiveness of PAP titration. Patients with oronasal masks have higher CPAP pressure, higher residual apnea-hypopnea index, lower sleep efficiency and higher wake time after sleep onset. Oronasal masks should not be recommended as the first choice for apnea patients. LEVEL OF EVIDENCE: Level 3.

Efficacy of nasal masks versus nasal pillows masks during continuous positive airway pressure titration for patients with obstructive sleep apnea.

PURPOSE: Nasal masks are usually the first choice for CPAP therapy, but patients may experience side effects. There are limited data regarding the efficacy of nasal pillows masks during CPAP titration. This study aimed to compare the polysomnography outcomes during CPAP titration while comparing two types of masks (nasal and pillows) and to assess whether or not the patient characteristics differed between mask preferences. METHODS: In a sleep-disorders clinic, we prospectively analyzed all patients undergoing CPAP titration for three consecutive months. CPAP pressures were manually titrated. Anthropometric data (age, sex, body mass index, and neck and waist circumferences) and OSA severity were documented. Patients completed a self-administered questionnaire that measured nasal obstruction (NOSE scale). Before titration, both types of masks were presented to patients, and each of them chose the one they preferred. RESULTS: Of 157 patients, 55% (n = 86) used nasal masks, and 45% (n = 71) used nasal pillows masks. There was no difference according to mask type chosen by age, sex, body mass index, neck and waist circumferences, and NOSE scale. Polysomnography outcomes were similar between the mask groups. The mean CPAP level was 9.4 ± 1.8 cm H2O for nasal masks and 9.1 ± 2.0 cm H2O for nasal pillows (p = 0.61). Residual apnea-hypopnea index was 3.0 ± 2.8 events/h for nasal mask and 3.5 ± 4.1 events/h for pillow mask (p = 0.28). Baseline AHI, body mass index, neck and waist circumferences, and residual AHI were independent predictors of a higher CPAP pressure for both groups (p < 0.0001). CONCLUSIONS: Nasal pillows masks seem to be as effective as nasal masks and may be considered to be an initial choice for CPAP titration.

Reduction of Serum Concentrations and Synergy between Retinol, ß-Carotene, and Zinc According to Cancer Staging and Different Treatment Modalities Prior to Radiation Therapy in Women with Breast Cancer.

The procedures used for breast cancer treatment are able to increase the level of oxidative stress and cause depletion of antioxidants. OBJECTIVES: To investigate the relationship between serum concentrations of retinol, ß-carotene, and zinc, according to breast cancer staging, considering different treatment modalities prior to radiation therapy and the synergistic action between these micronutrients. METHODS: This is a cross-sectional observational study comprising a cohort of patients with breast cancer which was carried out prior to radiation therapy. Patients were divided into 3 groups: G1 comprised women who had undergone breast-conserving surgery, G2 comprised those who had undergone chemotherapy, and G3 those who had undergone breast-conserving surgery and chemotherapy. Serum concentrations of retinol, ß-carotene, and zinc were quantified. Breast cancer staging was based on the TNM (Tumor, Node, Metastasis) classification of malignant tumors, a type of staging tool for different cancers. RESULTS: A total of 230 patients were assessed. A decrease of the serum concentrations of the micronutrients assessed as the staging level of the disease increased was observed. Surgery alone had a greater negative impact on serum concentrations of retinol. Considering the treatments prior to radiotherapy, patients undergoing surgery alone and chemotherapy associated with surgery had higher percentages of deficiency of ß-carotene and retinol. There was a positive correlation between the concentrations of zinc, retinol, and ß-carotene, showing a synergy between these micronutrients. CONCLUSION: A significant reduction in the serum concentrations of the assessed micronutrients was observed, according to the increase in breast cancer staging. The synergy between the micronutrients must be considered in order to maximize the benefits and minimize the adverse effects of irradiation to normal cells.

Retinol, ß-carotene and oxidative stress in systemic inflammatory response syndrome.

OBJECTIVE: patients suffering systemic inflammatory response syndrome (SIRS) constitute a group susceptible to elevated levels of oxidative stress. This study's aim is to evaluate the state of oxidative stress and levels of serum retinol and ß-carotene in these patients. METHODS: forty-six patients were divided into 2 groups: those those without diet (G1; n=18) and those with enteral nutritional support (G2; n=28). Serum levels of retinol and total carotenoids were measured. C-reactive protein (CRP) levels and Apache scores were also calculated. Oxidative stress was estimated by measuring thiobarbituric acid reactive substance (TBARS) levels. RESULTS: the patients' median age was 66.9 (SD=19.3) years. Lower concentrations of retinol and carotenoids were found in 68.6 and 66.7% of G1, respectively. In G2, despite average vitamin A levels being 8078 + 4035, retinol and ß-carotene were considered insufficient (31.2 and 33.4%, respectively). No difference was noted between the 2 groups, according to the variables studied, with the exception being PCR and ß-carotene (p=0.002; p=0.01). CONCLUSION: the data presented in this study supports the need to establish/revise clinical practices in treating SIRS patients, in light of this micronutrient's role in the immune system and antioxidant defense without it interfering with its toxicity.

Retinol, β-carotene and oxidative stress in systemic inflammatory response syndrome / Retinol, β-caroteno e estresse oxidativo na síndrome da resposta inflamatória sistêmica.

Objective: patients suffering systemic inflammatory response syndrome (SIRS) constitute a group susceptible to elevated levels of oxidative stress. This study’s aim is to evaluate the state of oxidative stress and levels of serum retinol and β-carotene in these patients. Methods: forty-six patients were divided into 2 groups: those those without diet (G1; n=18) and those with enteral nutritional support (G2; n=28). Serum levels of retinol and total carotenoids were measured. C-reactive protein (CRP) levels and Apache scores were also calculated. Oxidative stress was estimated by measuring thiobarbituric acid reactive substance (TBARS) levels. Results: the patients’ median age was 66.9 (SD=19.3) years. Lower concentrations of retinol and carotenoids were found in 68.6 and 66.7% of G1, respectively. In G2, despite average vitamin A levels being 8078 + 4035, retinol and β-carotene were considered insufficient (31.2 and 33.4%, respectively). No difference was noted between the 2 groups, according to the variables studied, with the exception being PCR and β-carotene (p=0.002; p=0.01). Conclusion: the data presented in this study supports the need to establish/revise clinical practices in treating SIRS patients, in light of this micronutrient’s role in the immune system and antioxidant defense without it interfering with its toxicity. .

Objetivo: pacientes que apresentam a síndrome da resposta inflamatória sistêmica (SIRS) constituem um grupo suscetível a níveis elevados de estresse oxidativo. O objetivo do presente estudo é avaliar o estado de estresse oxidativo e os níveis séricos de retinol e β-caroteno nesses pacientes. Métodos: quarenta e seis pacientes foram divididos em dois grupos: aqueles sem dieta (G1; n = 18) e aqueles com suporte nutricional enteral (G2, n = 28). Foram investigadas as concentrações séricas de retinol e carotenoides totais, proteína C reativa, estresse oxidativo e escore Apache. O estresse oxidativo foi avaliado por dosagem da peroxidação lipídica e estimado por meio da dosagem de TBARS (substâncias reativas ao ácido tiobarbitúrico). Resultados: a média de idade dos pacientes foi de 66,9 (±19,3). Baixas concentrações de retinol e carotenoides foram encontradas em 68,6 e 66,7% do G1, respectivamente. No G2, a concentração sérica média de vitamina A foi de 8078 (± 4035), e o retinol e o β-caroteno apresentaram percentual de inadequação de 31,2 e 33,4%, respectivamente. Não foi observada nenhuma diferença entre os dois grupos, de acordo com as variáveis estudadas, com exceção do PCR e do β-caroteno (p=0,002; p=0,01). Conclusão: os dados apresentados neste estudo indicam a necessidade de estabelecer/rever práticas clínicas no tratamento de pacientes com SIRS, tendo em conta o papel desse micronutriente no sistema imunológico e na defesa antioxidante, sem que isso interfira na sua toxicidade. .

Routine supplementation does not warrant the nutritional status of vitamin d adequate after gastric bypass Roux-en-Y.

UNLABELLED: Bariatric surgery can lead to nutritional deficiencies, including those related to bone loss. The aim of this study was to evaluate serum concentrations of calcium, vitamin D and PTH in obese adults before and six months after gastric bypass surgery in Roux-en-Y (RYGB) and evaluate the doses of calcium and vitamin D supplementation after surgery. METHODS: Retrospective longitudinal study of adult patients of both sexes undergoing RYGB. We obtained data on weight, height, BMI and serum concentrations of 25-hydroxyvitamin D, ionized calcium and PTH. Following surgery, patients received dietary supplementation daily 500 mg calcium carbonate and 400 IU vitamin D. RESULTS: We studied 56 women and 27 men. Preoperative serum concentrations of vitamin D were inadequate in 45% of women and 37% of men, while in the postoperative period 91% of women and 85% of men had deficiency of this vitamin. No change in serum calcium was found before and after surgery. Serum PTH preoperatively remained adequate in 89% of individuals of both sexes. After surgery serum concentrations remained adequate and 89% women and 83% men evaluated. CONCLUSION: Obesity appears to be a risk factor for the development of vitamin D. The results show that supplementation routine postoperative was unable to treat and prevent vitamin D deficiency in obese adults undergoing RYGB.

La cirugía bariátrica puede llevar deficiencias nutrionales, incluyendo aquellas relacionadas a perdida ósea. El objetivo de este estudio fue avaluar las concentraciones séricas de cálcio, vitamina D y PTH en adultos obesos, antes y seis meses pos cirugía de bypass Gástrico en Y-de-Roux (RYGB) y avaluar las dosis de calcio y vitamina D utilizada después da la cirugía. Métodos: Estudio longitudinal retrospectivo con pacientes adultos de ambos sexos que fueron submetidos al RYGB. Fueron obtenidos datos de peso, estatura e IMC y las concentraciones de 25-hidroxivitamina D, calcio iónicos y PTH. Pos cirugía, los pacientes recibieron la suplementación dietética diaria de 500 mg de carbonato de calcio y 400 UI de vitamina D. Resultados: Fueron avaluados 56 mujeres y 27 hombres. El preoperatorio las concentraciones séricas de vitamina D presentaron inadecuadas en 45% de las mujeres y 37% de los hombres, mientras en el periodo posoperatorio 91% de las mujeres y 85% de los hombres presentaron deficiencia de esta vitamina. Ninguna alteración en las concentraciones séricas de calcio fue encontrada antes ni pos la cirugía. Las concentraciones séricas de PTH en el preoperatorio se mantuvieron adecuadas en 89% de los individuos de ambos sexos. Pos la cirugía las concentraciones séricas se mantuvieron adecuadas en 89% y mujeres y 83% de los hombres avaluados. Conclusión: la obesidad puede ser un factor de riesgo para el desarrollo de la deficiencia de vitamina D. Los resultados enseñan que la suplementación fue incapaz de sanar y prevenir la deficiencia de vitamina D en adultos obesos submetidos RYGB.

Routine supplementation does not warrant the nutritional status of vitamin D adequate after gastric bypass Roux-en-Y / Rutina de suplementación no garantiza el estado nutricional de vitamina D adecuado para bypass gástrico en Y-de ROUX

Bariatric surgery can lead to nutritional deficiencies, including those related to bone loss. The aim of this study was to evaluate serum concentrations of calcium, vitamin D and PTH in obese adults before and six months after gastric bypass surgery in Roux-en-Y (RYGB) and evaluate the doses of calcium and vitamin D supplementation after surgery. Methods: Retrospective longitudinal study of adult patients of both sexes undergoing RYGB. We obtained data on weight, height, BMI and serum concentrations of 25-hydroxyvitamin D, ionized calcium and PTH. Following surgery, patients received dietary supplementation daily 500 mg calcium carbonate and 400 IU vitamin D. Results: We studied 56 women and 27 men. Preoperative serum concentrations of vitamin D were inadequate in 45% of women and 37% of men, while in the postoperative period 91% of women and 85% of men had deficiency of this vitamin. No change in serum calcium was found before and after surgery. Serum PTH preoperatively remained adequate in 89% of individuals of both sexes. After surgery serum concentrations remained adequate and 89% women and 83% men evaluated. Conclusion: Obesity appears to be a risk factor for the development of vitamin D. The results show that supplementation routine postoperative was unable to treat and prevent vitamin D deficiency in obese adults undergoing RYGB (AU)

La cirugía bariátrica puede llevar deficiencias nutricionales, incluyendo aquellas relacionadas a perdida ósea. El objetivo de este estudio fue avaluar las concentraciones séricas de cálcio, vitamina D y PTH en adultos obesos, antes y seis meses pos cirugía de bypass Gástrico en Y-de-Roux (RYGB) y avaluar las dosis de calcio y vitamina D utilizada después da la cirugía. Métodos: Estudio longitudinal retrospectivo con pacientes adultos de ambos sexos que fueron submetidos al RYGB. Fueron obtenidos datos de peso, estatura e IMC y las concentraciones de 25-hidroxivitamina D, calcio iónicos y PTH. Pos cirugía, los pacientes recibieron la suplementación dietética diaria de 500 mg de carbonato de calcio y 400 UI de vitamina D.Resultados: Fueron avaluados 56 mujeres y 27 hombres. El preoperatorio las concentraciones séricas de vitamina D presentaron inadecuadas en 45% de las mujeres y 37% de los hombres, mientras en el periodo posoperatorio 91% de las mujeres y 85% de los hombres presentaron deficiencia de esta vitamina. Ninguna alteración en las concentraciones séricas de calcio fue encontrada antes ni pos la cirugía. Las concentraciones séricas de PTH en el preoperatorio se mantuvieron adecuadas en 89% de los individuos de ambos sexos. Pos la cirugía las concentraciones séricas se mantuvieron adecuadas en 89% y mujeres y 83% de los hombres avaluados. Conclusión: la obesidad puede ser un factor de riesgo para el desarrollo de la deficiencia de vitamina D. Los resultados enseñan que la suplementación fue incapaz de sanar y prevenir la deficiencia de vitamina D en adultos obesos submetidos RYGB (AU)

NTPDase and 5'-nucleotidase activities from synaptosomes and platelets of rats exposed to cadmium and treated with N-acetylcysteine.

The purpose of the present investigation was to evaluate the hydrolysis of adenine nucleotides on synaptosomes and platelets obtained from rats exposed to cadmium (Cd) and treated with N-acetylcysteine (NAC). Rats received Cd (2 mg/kg) and NAC (150 mg/kg) by gavage every other day for 30 days. Animals were divided into four groups (n = 4-6): control/saline, NAC, Cd, and Cd/NAC. The results of this study demonstrated that NTPDase and 5'-nucleotidase activities were increased in the cerebral cortex synaptosomes of Cd-poisoned rats, and NAC co-treatment reversed these activities to the control levels. In relation to hippocampus synaptosomes, no differences on the NTPDase and 5'-nucleotidase activities of Cd-poisoned rats were observed and only the 5'-nucleotidase activity was increased by the administration of NAC per se. In platelets, Cd-intoxicated rats showed a decreased NTPDase activity and no difference in the 5'-nucleotidase activity; NAC co-treatment was inefficient in counteracting this undesirable effect. Our findings reveal that adenine nucleotide hydrolysis in synaptosomes and platelets of rats were altered after Cd exposure leading to a compensatory response in the central nervous system and acting as a modulator of the platelet activity. NAC was able to modulate the purinergic system which is interesting since the regulation of these enzymes could have potential therapeutic importance. Thus, our results reinforce the importance of the study of the ecto-nucleotidases pathway in poisoning conditions and highlight the possibility of using antioxidants such as NAC as adjuvant against toxicological conditions.

Methylmercury-induced changes in target organs of suckling rat pups.

Methylmercury (MeHg) is an organic form of mercury with toxic effects in multiple organs. The aim of the present investigation was to evaluate the in vivo effects of MeHg (1 and 4 mg/kg) given orally for seven consecutive days on adenosine deaminase (ADA), n-acetyl-ß-D-glucosaminidase (NAG) and ecto-nucleoside triphosphate phosphohydrolase (NTPDase) activities, and on lipid peroxidation in hippocampus, cerebral cortex, kidney and liver of suckling rat pups. The results showed that NAG activity and lipid peroxidation levels increased in the kidney in both treatments, whereas urinary NAG activity increased only in the 1 mg/kg treatment. Despite the fact that the lipid peroxidation increased in both cerebral cortex and hippocampus, the latter appeared to be more vulnerable to MeHg exposure as it also had an increase in ADA activity. Thus, although dietary MeHg modified renal cell function, it did not alter histological features in suckling rat pups. The results of our investigation are of significant importance because they demonstrated responses to exposition to low doses of MeHg in target organs during the development of the rat. Especially the kidney was affected by the oral exposure to MeHg, suggesting the vulnerability of this organ at this stage of development. Moreover, the urinary NAG may provide important data that could serve as basis for risk assessment purposes following MeHg exposure.

Enzymes that hydrolyze adenine nucleotides in patients with ischemic heart disease.

BACKGROUND: The extracellular nucleotides, ATP and ADP, as well as the nucleoside adenosine have been implicated in a great number of pathologic and physiological functions. However, extracellular adenine nucleotide levels are controlled by a complex cell surface-located group of enzymes called ectonucleotidases. We evaluated activities of enzymes that hydrolyze adenine nucleotides and nucleosides in platelets from patients with ischemic heart disease (IHD). METHODS: Sixty IHD patients were selected for the study. The activities of ectonucleoside triphosphate diphosphohydrolase (NTPDase, CD39), ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP), ecto-5'-nucleotidase and adenosine deaminase (ADA) were studied in isolated platelets of these patients, as well as the platelet aggregation and NTPDase expression. RESULTS: The results show that NTPDase, ecto-5'-nucleotidase, E-NPP activities and NTPDase expression were increased in platelets of IHD patients when compared with the control group (p < 0.05). On the other hand, ADA activity and platelet aggregation were decreased in IHD patients, when compared with the control group (p < 0.05). CONCLUSIONS: The pathological condition in IHD generates alterations in ectonucleotidase activities as a compensatory organic response to thrombotic events that occur in IHD.

Oxidative stress versus antioxidant defenses in patients with acute myocardial infarction.

Acute myocardial infarction (AMI) is a highly dynamic event, which is associated with increasing production of reactive oxygen species (ROS). The imbalance between ROS production and antioxidant defenses leads to the condition known as oxidative stress. The most widely recognized effect of increasing oxidative stress is the oxidation and damage of macromolecules, membranes, proteins, and DNA. Therefore, in this study we sought to evaluate oxidative stress and antioxidant defenses in patients with AMI. Lipid peroxidation, protein carbonyl levels, and enzymatic and nonenzymatic antioxidants were assessed in samples obtained from 40 AMI patients and 40 control patients. AMI was characterized by clinical, electrocardiographic, and laboratory criteria. The control group was divided into two groups of 20 patients: a control group with healthy patients and a risk group. Our results demonstrated an increase in substances reactive to thiobarbituric acid (TBARS) and carbonyl protein levels in the AMI and risk groups. In addition, a positive correlation was found between TBARS, carbonyl protein levels, and troponin I in AMI patients. Surprisingly, for the enzymatic antioxidant defenses, catalase and superoxide dismutase, we observed an increase in these parameters in the AMI and risk groups when compared with healthy patients. However, a decrease in nonenzymatic antioxidants such as vitamin C and vitamin E was observed in AMI patients when compared with the healthy group and the risk group. The increase in oxidative stress was probably a result of the elevation in ROS production due to the ischemic/reperfusion event that occurs in AMI, in addition to the decrease of nonenzymatic antioxidant defenses.

Activities of enzymes that hydrolyze adenine nucleotides in platelets from patients with rheumatoid arthritis.

OBJECTIVES: To investigate whether there are changes in the activity of the enzymes NTPDase, 5'-nucleotidase, E-NPP and ADA in platelets from patients with rheumatoid arthritis (RA). DESIGN AND METHODS: Thirty-five RA patients diagnosed with RA through American College of Rheumatology criteria, as well as 35 healthy patients were selected. NTPDase, 5'-nucleotidase, E-NPP and ADA activities were verified in platelets isolated from these patients. RESULTS: The results demonstrate that an increase in NTPDase (approximately 100%), 5'-nucleotidase (170%), E-NPP (approximately 100%) and ADA (approximately 45%) activities occurred in RA patients when compared to the control group. CONCLUSIONS: Ours results suggest an increase in the NTPDase, 5'-nucleotidase and E-NPP activities, which could be related to a compensatory organic response to excessive platelet aggregation which occurs during the inflammation. The increased ADA activity found in this work could lead to a decrease in the adenosine concentration in the circulation, which could explain the accelerated atherosclerosis found in patients with RA.

The activity and expression of NTPDase is altered in lymphocytes of multiple sclerosis patients.

BACKGROUND: Multiple sclerosis (MS) is a demyelinating neurological disease, which is presumed to be a consequence of infiltrating lymphocytes that are autoreactive to myelin proteins. ATP and adenosine contribute to fine-tuning immune responses and NTPDase (CD39) and adenosine deaminase (ADA) are important enzymes in the control of the extracellular levels of these molecules at the site of inflammation. We evaluated the activity and expression of NTPDase and adenosine deaminase (ADA) activity in lymphocytes from patients with the relapsing-remitting form of MS (RRMS). METHODS: This study involved 22 patients with RRMS and 22 healthy subjects as a control group. The lymphocytes were isolated from blood and separated on Ficoll density gradients and after isolation the NTPDase and ADA activities were determined. RESULTS: The NTPDase activity and expression were increased in lymphocytes from RRMS patients when compared with the control group (p<0.05). In addition, a decrease in ADA activity was observed in lymphocytes from these patients when compared to the control group (p<0.05). CONCLUSIONS: The regulation of ATP and adenosine levels by NTPDase and ADA activities may be important to preserve cellular integrity and to modulate the immune response in MS.

Ectonucleotidase and acetylcholinesterase activities in synaptosomes from the cerebral cortex of streptozotocin-induced diabetic rats and treated with resveratrol.

The aim of the present study was to investigate the effects of resveratrol (RV), an important neuroprotective compound on NTPDase, 5'-nucleotidase and acetylcholinesterase (AChE) activities in cerebral cortex synaptosomes of streptozotocin (STZ)-induced diabetic rats. The animals were divided into six groups (n=8): control/saline; control/RV 10mg/kg; control/RV 20mg/kg; diabetic/saline; diabetic/RV 10mg/kg; diabetic/RV 20mg/kg. After 30 days of treatment with resveratrol the animals were sacrificed and the cerebral cortex was removed for synaptosomes preparation and enzymatic assays. The results demonstrated that NTPDase and 5'-nucleotidase activities were significantly increased in the diabetic/saline group (p<0.05) compared to control/saline group. Treatment with resveratrol significantly increased NTPDase, 5'-nucleotidase activities in the diabetic/RV10 and diabetic/RV20 groups (p<0.05) compared to diabetic/saline group. When resveratrol was administered per se there was also an increase in the activities of these enzymes in the control/RV10 and control/RV20 groups (p<0.05) compared to control/saline group. AChE activity was significantly increased in the diabetic/saline group (p<0.05) compared to control/saline group. The treatment with resveratrol prevented this increase in the diabetic/RV10 and diabetic/RV20 groups. In conclusion, this study demonstrated that the resveratrol interfere with the purinergic and cholinergic neurotransmission by altering NTPDase, 5'-nucleotidase and AChE activities in cerebral cortex synaptosomes of diabetic rats. In this context, we can suggest that resveratrol should be considered potential therapeutics and scientific tools to be investigated in brain disorders associated with the diabetes.

NTPDase and acetylcholinesterase activities in silver catfish, Rhamdia quelen (Quoy & Gaimard, 1824) (Heptapteridae) exposed to interaction of oxygen and ammonia levels

The effects of various levels of oxygen saturation and ammonia concentration on NTPDase (ecto-nucleoside triphosphate diphosphohydrolase, E.C. 3.6.1.5) and acetylcholinesterase (AChE, E.C. 3.1.1.7) activities in whole brain of teleost fish (Rhamdia quelen) were investigated. The fish were exposed to one of two different dissolved oxygen levels, including high oxygen (6.5 mg.L-1) or low oxygen (3.5 mg.L-1), and one of two different ammonia levels, including high ammonia (0.1 mg.L-1) or low ammonia (0.03 mg.L-1) levels. The four experimental groups included the following (A) control, or high dissolved oxygen plus low NH3; (B) low dissolved oxygen plus low NH3; (C) high dissolved oxygen plus high NH3; (D) low dissolved oxygen plus high NH3. We found that enzyme activities were altered after 24 h exposure in groups C and D. ATP and ADP hydrolysis in whole brain of fish was enhanced in group D after 24 h exposure by 100 percent and 119 percent, respectively, compared to the control group. After 24 h exposure, AChE activity presented an increase of 34 percent and 39 percent in groups C and D, respectively, when compared to the control group. These results are consistent with the hypothesis that low oxygen levels increase ammonia toxicity. Moreover, the hypoxic events may increase blood flow by hypoxia increasing NTPDase activity, thus producing adenosine, a potent vasodilator.(AU)

No presente estudo, avaliou-se o efeito de diferentes níveis de saturação de oxigênio e amônia sobre a atividade das enzimas NTPDase (ecto-nucleosídeo trifosfato difosfohidrolase, E.C. 3.6.1.5) e acetilcolinesterase (AChE, E.C. 3.1.1.7) em encéfalo total de jundiás (Rhamdia quelen). Os peixes foram expostos a diferentes níveis de oxigênio dissolvido e amônia, níveis altos de oxigênio (6,5 mg/L) ou baixos de oxigênio (3,5 mg/L), e níveis altos de amônia (0,1 mg/L) ou baixos de amônia (0,03 mg/L). Os peixes foram divididos em quatro diferentes grupos: (A) controle ou alto nível de oxigênio dissolvido mais baixo nível de NH3; (B) baixo nível de oxigênio dissolvido mais baixo nível de NH3; (C) alto nível de oxigênio dissolvido mais alto nível de amônia; (D) baixo nível de oxigênio dissolvido mais alto nível de NH-3. As atividades de ambas as enzimas nos grupos C e D somente foram alteradas após 24 horas de exposição. A hidrólise do ATP e ADP em encéfalo total de jundiás foi aumentada após 24h de exposição para 104 por cento e 155 por cento no grupo D quando comparado ao grupo controle, respectivamente. A atividade da AChE apresentou após 24h de exposição um aumento de 37 por cento no grupo C e 27 por cento no grupo D, ambos comparados ao grupo controle. Os resultados obtidos corroboram com a hipótese que baixos níveis de saturação de oxigênio aumentam a toxicidade da amônia. Além disso, os eventos de hipóxia podem aumentar o fluxo sanguíneo, e este evento aumenta a atividade da NTPDase produzindo adenosina, um potente vasodilatador(AU)

Hydrolysis of adenine nucleotides in platelets from patients with acute myocardial infarction.

OBJECTIVES: To investigate the rate of ATP, ADP and AMP hydrolysis on the surface of platelets from acute myocardial infarction (AMI) patients. DESIGN AND METHODS: Twenty-five patients diagnosed with AMI, through clinical criteria, electrocardiographic changes and increase of cardiac biomarkers, as well as 25 healthy patients were selected. The hydrolysis of ATP, ADP and AMP was verified in isolated platelets of these patients. RESULTS: The results demonstrated that an increase in ATP (54%) and ADP (45%) hydrolysis occurred in AMI patients when compared to the control group. The hydrolysis of AMP also increased by 46% in AMI patients probably leading to an enhancement in the adenosine level. CONCLUSIONS: Our results suggest an increase in nucleotide hydrolysis in platelets from AMI patients, which could be related to a compensatory organic response to thrombotic events that occur in AMI.

Effect of high glucose levels in human platelet NTPDase and 5'-nucleotidase activities.

OBJECTIVES: The objective of this work was to evaluate the effect of different glucose levels on the ATP, ADP and AMP hydrolysis in the platelets of diabetic, hypertensive and diabetic/hypertensive participants. METHODS: The activities of the enzymes NTPDase (ATP and ADP hydrolysis) and 5'-nucleotidase (AMP hydrolysis), and CD39 expression were analyzed in human blood platelets of diabetic (DM-2), hypertensive (HT) and diabetic/hypertensive (DM-2/HT) patients. To evaluate the interference of glucose and fructose in NTPDase and 5'-nucleotidase activities, experiments were performed with glucose, fructose and mannitol concentrations ranging from 5 to 30 mM in platelet-rich plasma (PRP). Pre-incubation times of 10, 120 min and 24h were used. RESULTS: NTPDase and 5'-nucleotidase activities increased with increasing glucose and fructose concentrations (P<0.001) and the different times of pre-incubation did not interfere in ectonucleotidases activities (P>0.5). NTPDase and 5'-nucleotidase activities demonstrated a positive correlation between serum glucose levels and ATP and ADP hydrolysis in DM-2 and DM-2/HT patients. CD39 expression demonstrated that DM-2, HT and DM-2/HT groups presented a significant increase when compared to the control group (P<0.004). CONCLUSION: The hydrolysis of adenine nucleotides is enhanced in platelets of patients with diabetes and hypertension. We observed that an increasing glucose concentration had a direct effect on ATP, ADP and AMP hydrolysis. Furthermore, CD39 expression was enhanced in all patients groups, indicating that these enzyme activities are related with diabetes and hypertension.

Oxidative stress and erythrocyte acetylcholinesterase (AChE) in hypertensive and ischemic patients of both acute and chronic stages.

Ischemic stroke is a leading cause of mortality and disability particularly in the elderly. Hypertension is the most important risk factor in strokes, representing roughly 70% of all cases. Oxidative stress is believed to be one of the mechanisms taking part in neuronal damage in stroke. It is well documented that cholinergic system plays a key role in normal brain functions and in memory disturbances of several pathological processes, such as in cerebral blood flow regulation. This study investigated the oxidative status and acetylcholinesterase (AChE) activity in whole blood in patients diagnosed with acute and chronic stages of ischemia, as well as with hypertension. Malondialdehyde (MDA) levels and protein carbonylation content showed increased levels both in the acute ischemic groups and in the hypertensive group, when compared to the control. Catalase activity and reduced glutathione (GSH) levels in the acute group were also higher than in the hypertensive, chronic ischemic and control groups (p<0.05). The activity of AChE in acute ischemic patients was significantly higher than that presented by the control, hypertensive and chronic ischemic patients (p<0.05). The hypertensive group presented AChE activity significantly lower than control and chronic groups. In spite of having a defined location the ischemic event results in a systemic disorder that induces changes, which can be detected by measuring the peripheral markers of oxidative stress and AChE activity in erythrocytes.