Neutrophil function and lipid peroxidation in a rat model of multiple organ failure

Multiple organ failure (MOF) was induced by sterile intraperitoneal inoculation of zymosan in the rat. This results in a typical triphasic illness with maximal clinical signs at Days 2 and 14. In this study, granulocyte superoxide production (unstimulated and phorbol myristic acid stimulated) was studied as well as lipid peroxidation (TBAR) in plasma, liver, and lung tissue. Mainly TBAR levels in liver and lung tissue closely correlated with the triphasic clinical illness, while bacteriological data did not. It is concluded that the severe inflammatory response in this experimental model probably is the result of excessive toxic oxygen radical production. The first phase of illness may mainly be due to oxygen radical formation by activated PMN, the third phase of illness to the production of lysosomal enzymes (proteinases) from PMN, and activated macrophages as indicated by elevated N-acetylglucosaminidase levels.     

On the role of astrocytes in epilepsy: a functional modeling approach

In the present research, we extend a biologically plausible cortical neural population model (CPM), which was developed previously in the literature, by integrating the functional role of astrocytes in the synaptic transmission in the model. In other words, the original CPM is modified to consider neuron-astrocyte interaction. Then, two modified CPMs (MCPMs) are coupled via excitatory synapses; the astrocytes are also coupled through gap junctions. Using the coupled MCPMs (CMCPMs), it is demonstrated that the healthy astrocytes provide appropriate feedback control in regulating neural activity. As a result, the astrocytes compensate the coupling variations between CPMs in order to maintain the normal level of synchronized behavior. Next, malfunction of astrocytes in the regulatory feedback loop as one of the plausible causes of seizures is investigated. In this way, dysfunctional astrocytes are not any more able to regulate the excessive increase of the inter-population coupling strength. Consequently, disruption of the homeostatic function of astrocytes may initiate the hypersynchronous firing of neurons. This suggests that the neuron-astrocyte interaction may represent a novel target to develop effective therapeutic strategies for epilepsy.     

Effect of low fluency dentin conditioning on tensile bond strength of composite bonded to Er:YAG laser-prepared dentin: a preliminary study

Several studies in the literature have previously shown that the bond strength of a composite bonded to dentin is almost equivalent as when dentin is prepared by either bur or Er:YAG laser. The aim of this preliminary study is to assess the hypothesis that dentin conditioning at low fluency by means of Er:YAG laser can improve the value of adhesion of composites resin to dentin. Sixty surfaces of caries-free human third molars extracted for orthodontic purposes were randomly divided into five groups of 12 teeth. The bur group was the control, prepared using bur, group L was prepared using Er:YAG 200 mJ, SSP (50 μs), 20 Hz, 15 seconds of sweeping, for groups L80, L100, L120, they were prepared first, with the same parameters of the group L 200, and then they received a conditioning, which is, respectively, 15 s of irradiations at: 80 mJ (SSP, 10 Hz), 100 mJ (SSP, 10 Hz), and 120 mJ (SSP, 10 Hz). All samples were restored in a single-component adhesive system: Xenon (DENTSPLY), and ceramX (DENTSPLY) as the resin composite. The specimens were submitted to tensile bond strength test using a universal testing machine. Data were submitted to statistical analysis using ANOVA coupled to a Tukey-Kramer test at the 95% level. The mean values in MPa were 33.3 for group B, 36.73 for group L 200, 41.7 for group L80, 37.9 for group L100, and 39.1 for group L120. Our results showed that dentin conditioning at a low fluency of 12.58 J/cm² per pulse, with 80 mJ output energy and 50-μs pulse duration can significantly improve tensile bond strength of a composite bonded to Er:YAG laser-prepared dentine.     

Donation frequency of blood donors participating in a prospective cohort study of iron status

BACKGROUND: Blood centers are interested in understanding determinants of frequent blood donation. We hypothesized that participation in uncompensated research could result in higher donation rates. STUDY DESIGN AND METHODS: Donation rates for 2425 subjects from six US blood centers enrolled in the Retrovirus Epidemiology Donor Study‐II Donor Iron Status Evaluation Study were compared to those of nonenrolled donors (n = 202,383). Over 15 months, we compared mean donation rates and adjusted rate ratios (RRs) between enrolled and nonenrolled for three subgroups, first‐time, reactivated, and frequent donors, and donation rates before and after the study enrollment period for frequent donors only. RESULTS: Enrolled donors had higher 15‐month mean donation rates than nonenrolled donors (first‐time, 1.21 [RR = 1.91]; reactivated, 1.68 [RR = 1.83]; frequent, 3.40 [RR = 1.12]). However, frequent donors donated at approximately the same rate after enrollment as they did before enrollment in the study (3.62 per 15 months [RR = 1.12]). CONCLUSION: Donors enrolled in the study donated at a higher rate than nonenrolled donors, but frequent donors remained consistent in their donation frequency both before and after enrollment. Although increased donation rates could have been causally related to study enrollment, we cannot rule out an enrollment bias whereby more committed donors were more likely to enroll in the study.