Efeito da endotoxemia na temperatura corporal, pressão arterial média e nas concentrações de nitrato e lactato plasmáticos em ratos / Effect of endotoxemia on body temperature, mean arterial pressure, and nitrate and lactate plasma concentrations in rats

Na endotoxemia e na sepse alterações nos sinais vitais e em biomarcadores estão presentes e sinalizam o grau de comprometimento fisiológico. Embora a interpretação sobre as concentrações do óxido nítrico (NO) e do lactato plasmáticos na pressão arterial sejam bem estabelecidas na literatura, elucidações sobre suas participações na temperatura corporal ainda são incipientes. Assim, este estudo teve como objetivo avaliar o efeito da endotoxemia na temperatura corporal, pressão arterial média e correlacionar esses valores com os biomarcadores NO e lactato plasmáticos. Foram utilizados 40 ratos divididos igualmente em cinco grupos experimentais. A indução da endotoxemia foi realizada por meio da administração endovenosa de lipopolissacarídeo (LPS) bacteriano, respectivamente 0,5 mg/Kg, 1,5 mg/Kg, 3,0 mg/Kg e 10 mg/Kg. O grupo controle recebeu 0,5 mL de solução salina. O experimento teve duração de seis horas. Na 0h (medida basal) foram coletadas amostras de sangue (0,4 mL) para dosagem do NO e lactato plasmáticos e obtidos os valores de temperatura corporal e pressão arterial média, na sequência os modelos experimentais foram induzidos de acordo com o grupo e a dose de LPS. O mesmo procedimento para as análises das variáveis investigadas foi realizado na 2a, na 4a e na 6a hora. A temperatura corporal e a pressão arterial foram registradas em intervalos de 15 minutos. Nossos resultados mostram que os animais que receberam LPS nas doses de até 3,0 mg/Kg apresentaram aumento significativo na temperatura corporal em relação ao grupo com 10 mg/Kg, que apresentou diminuição nesses valores. O aumento nas concentrações de NO e lactato plasmáticos nos grupos com LPS foram significativamente superiores ao grupo que recebeu solução salina e estiveram correlacionados com o aumento na temperatura corporal. O grupo com 10 mg/Kg também apresentou correlação inversa com os níveis da pressão arterial média. Em conclusão, as variações na temperatura corporal observadas neste estudo mostram efeito dose-dependente de LPS, além disso, em sua maioria os parâmetros vitais analisados estiveram correlacionados com o aumento nas concentrações dos biomarcadores NO e lactato plasmáticos

During endotoxemia and sepsis changes in vital signs and biomarkers are present, which may indicate a degree of physiological impairment. Although the interpretation on plasma nitric oxide (NO) and plasma lactate concentrations in blood pressure are well established in the literature, elucidations about their participation in body temperature are still incipient. Thus, this study aimed to evaluate the effect of endotoxemia on body temperature, mean arterial pressure correlating these changes with NO and plasma lactate concentrations. In our study we used 40 rats equally divided in five experimental groups. Induction of endotoxemia was performed by intravenous administration of bacterial lipopolysaccharide (LPS), being 0.5 mg / kg, 1.5 mg / kg, 3.0 mg / kg and 10 mg / kg and control group received 0.5 mL of saline. The experiment lasted six hours. At baseline, blood samples (0.4 mL) were collected for plasma NO and plasma lactate measurements and body temperature and mean arterial blood pressure values were obtained. The same procedure was performed for the analysis of all the variables at 2 nd, 4 th and 6 th hours. Body temperature and blood pressure were recorded at each 15 minute intervals. Our results show that animals receiving LPS at doses up to 3.0 mg / kg showed a significant increase in body temperature in relation to the 10 mg / kg group, which presented a decrease in these values. The increase in NO concentrations and plasma lactate in the LPS groups were significantly higher than the saline group and correlated with the increase in body temperature. The 10 mg / kg group also showed a negative correlation with mean arterial pressure levels. In conclusion, the changes in body temperature observed in this study show a dose-dependent effect of LPS, in addition, most of the vital parameters analysed were correlated with the increase in the concentrations of NO biomarkers and plasma lactate

Hepatic toxicity caused by PLGA-microspheres containing usnic acid from the lichen C ladonia substellata (AHTI) during pregnancy in Wistar rats

ABSTRACT This study aimed to evaluate the teratogenic and hepatotoxic potential of the usnic acid encapsulated into PLGA-microspheres. In total, 12 female Wistar rats in pregnancy were randomly distributed in the control group (n= 6) that received 1.0 mL of physiological solution and treatment group (n= 6) that received 25 mg/kg of encapsulated usnic acid by oral administration. All females were euthanized at day 20 of pregnancy and their fetuses were removed and analyzed. During the pregnancy was observed a reduction in weight gain. There was no difference in serum transaminases levels analyzed as well as any difference in liver weight in both groups. The histomorphometric analysis of the liver from the treatment group revealed an increase in number of hepatocytes and a decrease in nuclear area of these cells. Moreover, no alteration was observed in cell area of hepatocytes or number of Kupffer cells. The fetuses had an increase in total number of hepatocytes and a reduction in the amount of megakaryocytes. These results show the hepatotoxic potential of usnic acid during pregnancy. However, its toxicity can be minimized by encapsulation in microspheres.

Is heart rate variability a feasible method to determine anaerobic threshold in progressive resistance exercise in coronary artery disease?

ABSTRACT Background Recent studies have shown that the magnitude of the metabolic and autonomic responses during progressive resistance exercise (PRE) is associated with the determination of the anaerobic threshold (AT). AT is an important parameter to determine intensity in dynamic exercise. Objectives To investigate the metabolic and cardiac autonomic responses during dynamic resistance exercise in patients with Coronary Artery Disease (CAD). Method Twenty men (age = 63±7 years) with CAD [Left Ventricular Ejection Fraction (LVEF) = 60±10%] underwent a PRE protocol on a leg press until maximal exertion. The protocol began at 10% of One Repetition Maximum Test (1-RM), with subsequent increases of 10% until maximal exhaustion. Heart Rate Variability (HRV) indices from Poincaré plots (SD1, SD2, SD1/SD2) and time domain (rMSSD and RMSM), and blood lactate were determined at rest and during PRE. Results Significant alterations in HRV and blood lactate were observed starting at 30% of 1-RM (p<0.05). Bland-Altman plots revealed a consistent agreement between blood lactate threshold (LT) and rMSSD threshold (rMSSDT) and between LT and SD1 threshold (SD1T). Relative values of 1-RM in all LT, rMSSDT and SD1T did not differ (29%±5 vs 28%±5 vs 29%±5 Kg, respectively). Conclusion HRV during PRE could be a feasible noninvasive method of determining AT in CAD patients to plan intensities during cardiac rehabilitation.

Biocompatibilidad de células madres mesenquimales de tejido gingival humano en cultivoconun andamiaje de polímero sintético de ácido poliláctico (OPLA) / Biocompatibility of mesenchymal stem cells derived from human gingival tissue in culture with a scaffold of a synthetic polymer open porosity polylactic acid polymer (OPLA)

La ingeniería tisular se plantea como tratamiento ideal para la regeneración de tejidos con la utilización de andamiajes, células madres y factores de crecimiento. Las células madres de origen gingival plantean ventajas de obtención, mientras que el OPLA 3D permite cultivos de alta densidad celular. El objetivo de esta investigación fue evaluar la biocompatibilidad de células madres de origen gingival en OPLA. Las células se obtuvieron de tejido gingival y fueron caracterizadas fenotípica y funcionalmente. La biocompatibilidad se evaluó mediante la proliferación celular, prueba de viabilidad con azul tripán y diferenciación celular a linaje condrogénico y osteogénico. El recultivo del constructo se utilizó para evaluar la capacidad de transporte. Las células al interior del OPLA se visualizaron mediante cortes teñidos con H-E. Las células madres mesenquimales en OPLA proliferaron, 80% de confluencia a la cuarta semana. La viabilidad celular en OPLA fue de 83,32%. En el recultivo, las células comienzan a proliferar a la semana. El OPLA permite la diferenciación celular a linaje condrogénico y osteogénico. Se observan células al interior del OPLA, permite la proliferación, viabilidad y diferenciación celular. El OPLA podría ser utilizado como andamiaje celular para la ingeniería de tejidos.

Tissue engineering arises as the ideal treatment for tissue regeneration with the use of scaffolds, stem cells and growth factors. Stem cells derived from gingival tissue present benefits in its objection. 3D OPLA allow high cell density cultures. The objective of this study was to evaluate the biocompatibility of gingival stem cells in OPLA. Cells were obtained from gingival tissue and were characterized phenotypically and functionally. The biocompatibility was evaluated through cell proliferation, viability test with trypan blue and cell differentiation to chondrogenic and osteogenic lineage. Recultivation of the construct was used to evaluate transportability. Cells inside OPLA were visualized by stained sections with H&E. Mesenchymal stem cells proliferated in OPLA, 80% confluence at the fourth week. Cell viability in OPLA was 83.32%. In recultivation, cells start proliferating in a week. OPLA allows cell differentiation to chondrogenic and osteogenic lineage. Cells were observed within OPLA. In conclusion OPLA allows proliferation, viability and cell differentiation. OPLA could be used as scaffolds for cells in tissue engineering.

Long-term degradation of resin-based cements in substances present in the oral environment: influence of activation mode

Indirect restorations in contact with free gingival margins or principally within the gingival sulcus, where the presence of organic acids produced by oral biofilm is higher, may present faster degradation of the resin-based cement pellicle. Objectives To investigate the degradation of four resin-based cements: Rely X ARC (R), Variolink II (V), Enforce (E) and All Cem (A), after immersion in distilled water (DW), lactic acid (LA) and artificial saliva (AS) and to analyze the influence of the activation mode on this response. Material and Methods Two activation modes were evaluated: chemical (Ch) and dual (D). In the dual activation, a two-millimeter thick ceramic disk (IPS Empress System) was interposed between the specimen and light-curing unit tip. Specimens were desiccated, immersed in distilled water, artificial saliva and lactic acid 0.1 M at 37°C for 180 days, weighed daily for the first 7 days, and after 14, 21, 28, 90 and 180 days and were desiccated again. Sorption and solubility (µg/mm 3 ) were calculated based on ISO 4049. The data were submitted to multifactor analysis of variance (MANOVA) and Tukey's HSD test for media comparisons (α=0.05). Results Sorption was higher after immersion in LA (p<0.05) and increased significantly with time (p<0.05). Sorption was influenced by the activation mode: Ch>D (p<0.05). The lowest solubility was presented by R (p<0.05). Conclusions Lactic acid increased the degradation of resin-based cements. Moreover, the physical component of activation, i.e., light-activation, contributed to a low degradation of resin-based cements. .

Presence of bound substrate in lactate dehydrogenase from carp liver.

While attempting to purify UDP-galactose 4-epimerase from carp liver extract at pH 8.0, it was observed that the preparation even after dialysis could reduce NAD to NADH, interfering epimerase assay. The NAD reduction activity and the epimerase were co-eluted in a series of chromatographic steps. Mass spectrometric analysis of semi-purified fraction revealed that carp liver lactate dehydrogenase (LDH) contained bound lactate which was converted to pyruvate in the presence of NAD. The enzyme-bound lactate and the association with epimerase stabilized LDH from trypsin digestion and thermal inactivation at 45°C by factors of 2.7 and 4.2 respectively, as compared to substrate-free LDH. LDH and epimerase do not belong to any one pathway, but are the rate-limiting enzymes of two different pathways of carbohydrate metabolism. Typically, strongly associated enzymes work in combination, such as two enzymes of the same metabolic pathway. In that background, co-purification of LDH and epimerase as reloaded in this study was an unusual phenomenon.

Surface roughness of orthodontic band cements with different compositions

OBJECTIVES: The present study evaluated comparatively the surface roughness of four orthodontic band cements after storage in various solutions. MATERIAL AND METHODS: Eight standardized cylinders were made from 4 materials: zinc phosphate cement (ZP), compomer (C), resin-modified glass ionomer cement (RMGIC) and resin cement (RC). Specimens were stored for 24 h in deionized water and immersed in saline (pH 7.0) or 0.1 M lactic acid solution (pH 4.0) for 15 days. Surface roughness readings were taken with a profilometer (Surfcorder SE1200) before and after the storage period. Data were analyzed by two-way ANOVA and Tukey's test (comparison among cements and storage solutions) or paired t-test (comparison before and after the storage period) at 5 percent significance level. RESULTS: The values for average surface roughness were statistically different (p<0.001) among cements at both baseline and after storage. The roughness values of cements in a decreasing order were ZP>RMGIC>C>R (p<0.001). After 15 days, immersion in lactic acid solution resulted in the highest surface roughness for all cements (p<0.05), except for the RC group (p>0.05). Compared to the current threshold (0.2 µm) related to biofilm accumulation, both RC and C remained below the threshold, even after acidic challenge by immersion in lactic acid solution. CONCLUSIONS: Storage time and immersion in lactic acid solution increased the surface roughness of the majority of the tested cements. RC presented the smoothest surface and it was not influenced by storage conditions.

Effects of combined mechanical stimulation on the proliferation and differentiation of pre-osteoblasts

We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 pre-osteoblasts were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with polycaprolactone and poly-L-lactic acid using the salt leaching method. The cells were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10% strain for cyclic strain and 1.0 MHz and 30 mW/cm2 for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. Mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly up to 10 days when measured with the cell counting kit-8. However, gene expression analysis of collagen type-I, osteocalcin, RUNX2, and osterix revealed that the combined mechanical stimulation accelerated the matrix maturation of MC3T3-E1 cells. These results indicate that the combined mechanical stimulation can enhance the differentiation of pre-osteoblasts more efficiently than simple stimuli, in spite of no effect on cell proliferation.

In vitro interactions between lactic acid solution and art glass-ionomer cements

OBJECTIVES: Production of acids such as lactic acid contributes to establish a cariogenic environment that leads to dental substrate demineralization. Fluoride plays an important role in this case and, as fluoride-releasing materials, glass-ionomer cements are expected to contribute to minimize deleterious reactions. This study evaluated interactions of glass-ionomer cements used in atraumatic restorative treatment (ART-GICs) with an aqueous lactic acid solution, testing the null hypotheses that no changes occur in the pH of the solution or on the surface roughness and mass of the ART-GICs when exposed to lactic acid solution over a 6-week period. MATERIAL AND METHODS: Ketac Molar, Fuji IX, Vitro Molar and Magic Glass were tested, and compared to Filtek Z250 and Ketac Fil Plus as control groups. Six specimens of each material were made according to manufacturers' instructions. The pH of the solution and roughness and mass changes of each specimen were determined over 6 weeks. Each specimen was individually stored in 2 mL of 0.02 M lactic acid solution for 1 week, renewing the solution every week. pH of solution and mass of the specimens were monitored weekly, and surface roughness of the specimens was assessed before and at the end of the 6-week acid challenge. pH and mass data were analyzed statistically by repeated measures using one-way ANOVA and Tukey's post-hoc tests for each material. Paired t-tests were used for roughness analysis. Tukey's post-hoc tests were applied to verify differences of final roughness among the materials. Significance level was set at 5 percent. RESULTS: The null hypotheses were partially rejected. All materials were able to increase the pH of the lactic acid solution and presented rougher surfaces after immersion, while mass change was minimal and generally not statistically significant. CONCLUSIONS: These findings can be helpful to predict the performance of these materials under clinical conditions. A ...

Obtención de microesferas biodegradables de ácido poli L-láctico cargadas con doxorubicina / Obtention of biodegradable microspheres of poly l-lactic acid loaded with doxorubicin

Se ha demostrado que las microesferas biodegradables de ácido poli L-láctico como portadores de fármacos proporcionan una liberación controlada y mantenida del principio activo, disminuyendo los efectos colaterales que estos pueden provocar. Por este motivo, se propuso evaluar la influencia de parámetros como el rendimiento, la eficiencia de encapsulación y el diámetro medio de las partículas, en el proceso de preparación de microesferas cargadas con doxorubicina, por el método de emulsión múltiple y evaporación del solvente. Se comprobó que la concentración de alcohol polivinílico y cloruro de sodio, así como la baja temperatura en la fase acuosa externa contribuyen a lograr mejores resultados en las características físico-químicas de las microesferas obtenidas

The construction and investigation of PLGA artificial bone by biomimetic mineralization / 华中科技大学学报（医学）（英德文版）

To modify the surface property of poly lactide-co-glycolide (PLGA) by biomimetic mineralization to construct a new kind of artificial bone. PLGA films and 3-diamensional (3-D) porous scaffolds hydrolyzed in alkaline solution were minerilized in SBF for 14 days. The morphology and composition of the mineral grown on PLGA were analyzed with SEM, FTIR and XRD. The porosity of the scaffolds was detected by using the liquid displacement method. The compressive strength of the scaffolds was detected by using a Shimadzu universal mechanic tester. An obvious mineral coating was detected on the surface of films and scaffolds. The main component of the mineral was carbonated hydroxyapatite (HA) similar to the major mineral component of bone tissues. The porosity of the un-mineralized and mineralized porous scaffolds was (84.86 +/- 8.52) % and (79.70 +/- 7.70) % respectively. The compressive strength was 0.784 +/- 0.156 N/mm2 in un-mineralized 3-D porous PLGA and 0.858 +/- 0.145 N/mm2 in mineralized 3-D porous PLGA. There were no significant differences between the mineralized and un-mineralized scaffolds (P > 0.05) in porosity and biomechanics. Biomimetic mineralization is a suitable method to construct artificial bone.

L (+) lactic acid fermentation and its product polymerization

Lactic acid has been first introduced to us as early as 1780 as a sour component of milk. Ever since we have found its applications in food, pharmaceutical, cosmetic industries etc. Now there are emerging uses as a potential feedstock for the biodegradable polymer industry. The microorganisms being used for lactic acid fermentation, the raw materials reported, the various novel fermentation processes and its processing methods have been reviewed. The properties and applications of lactic acid, its derivatives and polymer have been discussed. The various routes to polymerization and the companies presently involved in lactic acid production have been covered.

Terapia de reemplazo, una teoría de manipulación genética para la prevención de la caries dental / Replacement therapy, a theory of genetic manipulation for the prevention of dental caries

La caries es una enfermedad infecciosa, transmisible y sacarosa dependiente. Su etiología está basada en los postulados de Koch. La patología molecular muestra que el ácido láctico producido por la lactatodehidrogenasa del Streptococcus mutans es el responsable final de la desmineralización del esmalte. Objetivos: revisar en la literatura la propuesta de una nueva forma de prevenir la enfermedad: la "terapia de reemplazo" (basada en ingeniería genética ya que se remueve al Streptococcus mutans el gen que codifica a la lactato deshidrogenasa), con el fin de discutir aspectos éticos y de seguridad al implantar la nueva cepa para colonizar los nichos de la flora nativa. Métodos: buscar, revisar y criticar bibliografía obtenida de forma tradicional y publicadas en internet. Resultados: la habilidad de la bacteria no cariogénica para desplazar a la cepa nativa y colonizar su nicho está bien documentada en literatura pero no se encuentran respuesta sobre la estabilidad de la cepa y sobre potenciales riesgos que cuestionen la seguridad del proceso al ser utilizado por todos. Conclusiones: actualmente la terapia de reemplazo debe considerarse como una innovadora propuesta para la prevención de la caries, con perspectivas de ser una hipótesis demostrable que implica un costo beneficio favorable para su aplicación masiva

Estabilidad química y liberación de fluoruro de ionómero vítreos y resinas / Chemical stability and fluoride release from glass ionomer cements and composite resins

El objetivo del presente trabajo fue determinar la estabilidad química (en agua y en medio ácido) y la liberación de fluoruro de ionómeros vítreos y resinas, en distintos períodos de tiempo. La desintegración de ionómeros y resinas en agua fue nula, mientras que en medio ácido fue variable según las características de cada producto. El grado de liberación de fluoruro en orden decreciente fue: Ariston pHc, ionómeros, resinas compómeros y los composites restantes

Regeneración ósea guiada de cara al año 2000. Consideraciones clínicas y biológicas / Guided bone regeneration facing the year 2000. Clinical and biologic considerations

La regeneración ósea guiada representa hoy una de las terapias de mayor éxito para el manejo conjunto a la colocación de implantes. Durante los últimos años el uso de membranas para la regeneración ósea ha ido combinada desde membranas no reabsorbibles hasta membranas reabsorbibles. El presente artículo pretende mostrar a fondo los diferentes tipos de membranas que se tienen en el mercado, así como los resultados mostrados con el uso de las mismas. Asimismo, se hace un ligero repaso de las indicaciones para la regeneración ósea guiada y las propiedades que debe tener una membrana para poder ser utilizada en la regeneración ósea guiada