DNA damage and nitric oxide synthesis in experimentally infected Balb/c mice with Trypanosoma cruzi

This study aimed to evaluate whether experimental Chagas disease in acute phase under benznidazole therapy can cause DNA damage in peripheral blood, liver, heart, and spleen cells or induce nitric oxide synthesis in spleen cells. Twenty Balb/c mice were distributed into four groups: control (non-infected animals); Trypanosoma cruzi infected; T. cruzi infected and submitted to benznidazole therapy; and only treated with benznidazole. The results obtained with the single cell gel (comet) assay showed that T. cruzi was able induce DNA damage in heart cells of both benznidazole treated or untreated infected mice. Similarly, T. cruzi infected animals showed an increase of DNA lesions in spleen cells. Regarding nitric oxide synthesis, statistically significant differences (p < 0.05) were observed in all experimental groups compared to negative control, the strongest effect observed in the T. cruzi infected group. Taken together, these results indicate that T. cruzi may increase the level of DNA damage in mice heart and spleen cells. Probably, nitric oxide plays an important role in DNA damaging whereas benznidazole was able to minimize induced T. cruzi genotoxic effects in spleen cells. © 2006 Elsevier Inc. All rights reserved.

The polytraumatized or multiply injured child

10.1 In the severely injured infant and child the following age-specific facts should be kept in mind: ■ Larger head to body weight ratio (head often exposed to injury, neck injury) ■ Larger body surface area to body volume ratio (hypothermia) ■ More elastic thoracic wall (internal injury possible without external signs) ■ Thinner abdominal wall where abdominal organs are below the rib cage (liver, spleen injury) ■ Smaller total blood volume ■ Narrow airways ■ Long compensation of blood loss by tachycardia followed by rapid decompensation of circulatory status if left untreated 10.2 Child abuse is frequent: about 3%–7% of children under 18 years suffer from child abuse in some manner. The incidence and prevalence depend on the development of a country’s social service agencies and on the level of health professionals’ awareness of the problem. The estimated number of unreported cases is high. Child abuse affects children of all socioeconomic, ethnic, and religious boundaries. There is no gender preponderance. It occurs at any age, but infants and toddler have a higher risk than older children.

Effect of lipopolysaccharide on alteration of phospholipids and their fatty acid composition in spleen and thymus by in vitro metabolic labeling

Lipopolysaccharide (LPS) is an endotoxin, a potent stimulator of immune response and induction of LPS leads to acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). ARDS is a life-threatening disease worldwide with a high mortality rate. The immunological effect of LPS with spleen and thymus is well documented; however the impact on membrane phospholipid during endotoxemia has not yet been studied. Hence we aimed to investigate the influence of LPS on spleen and thymus phospholipid and fatty acid composition by 32P]orthophosphate labeling in rats. The in vitro labeling was carried out with phosphate-free medium (saline). Time course, LPS concentration-dependent, pre- and post-labeling with LPS and fatty acid analysis of phospholipid were performed. Labeling studies showed that 50 mu g LPS specifically altered the major phospholipids, phosphatidylcholine and phosphatidylglycerol in spleen and phosphatidylcholine in thymus. Fatty acid analysis showed a marked alteration of unsaturated fatty acids/saturated fatty acids in spleen and thymus leading to immune impairment via the fatty acid remodeling pathway. Our present in vitro lipid metabolic labeling study could open up new vistas for exploring LPS-induced immune impairment in spleen and thymus, as well as the underlying mechanism.

A role for regulatory T cells in renal acute kidney injury

Ischemia reperfusion injury (IRI) is a potential contributor for the development of chronic allograft nephropathy. T cells are important mediators of injury, even in the absence of alloantigens. We performed a depletion of TCD4(+)CTLA4(+)Foxp3(+) cells with anti-CD25(PC61), a treatment with anti-GITR (DTA-1) and rat-IgG, followed by 45 min of ischemia and 24/72 h of reperfusion, and then analyzed blood urea, kidney histopathology and gene expression in kidneys by QReal Time PCR. After 24 h of reperfusion, depletion of TCD4(+)CTLA4(+)Foxp3(+) cells reached 30.3%(spleen) and 67.8%(lymph nodes). 72 h after reperfusion depletion reached 43.1%(spleen) and 90.22%(lymph nodes) and depleted animals presented with significantly poorer renal function, while DTA-1 (anti-GITR)-treated ones showed a significant protection, all compared to serum urea from control group (IgG: 150.10 +/- 50.04; PC61: 187.23 +/- 31.38; DTA-1: 64.53 +/- 25.65, mg/dL, p<0.05). These data were corroborated by histopathology. We observed an increase of HO-1 expression in animals treated with DTA-1 at 72 h of reperfusion with significant differences. Thus, our results suggest that PC61 (anti-CD25) mAb treatment is deleterious, while DTA-1 (anti-GITR) mAb treatment presents a protective role in the renal IRI, indicating that some regulatory populations of T cells might have a role in IRI. (C) 2009 Elsevier B.V. All rights reserved.

TLR2 and TLR4 expression after kidney ischemia and reperfusion injury in mice treated with FTY720

Ischemia and reperfusion injury (IR) is an antigen independent inflammatory process that causes tissue damage. After IR, kidneys up-regulate leukocyte adhesion molecules and toll-like receptors (TLRs). Moreover, injured kidneys can also secrete factors (i.e. heat shock protein) which bind to TLRs and trigger intracellular events culminating with the increase in the gene expression of inflammatory cytokines. FTY720 is an immunomodulatory compound and protects at least in part kidneys submitted to IR. The mechanisms associated with FTY720`s beneficial effects on kidneys after IR remain elusive. We investigated whether FTY720 administration in mice submitted to kidney IR is associated with modulation of TLR2 and TLR4 expression. C57BL/6 mice submitted to 30 min of renal pedicles clamp were evaluated for serum parameters (creatinine, urea and nitric oxide), kidney histology, spleen and kidney infiltrating cells expression of TLR2 and TLR4, resident kidney cells expression of TLR2 and TLR4 and IL-6 protein expression in kidney. FTY720-treated mice presented decrease in serum creatinine, urea and nitric oxide, diminished expression of TLR2 and TLR4 both in spleen and kidney infiltrating cells, and reduced kidney IL-6 protein expression in comparison with IR non-treated mice. However, acute tubular necrosis was present both in IR non-treated and IR + FTY720-treated groups. Also, FTY720 did not prevent TLR2 and TLR4 expression in kidney resident cells. In conclusion, FTY720 can promote kidney function recovery after IR by reducing the inflammatory process. Further studies are needed in order to establish whether TLR2 and TLR4 down regulation should be therapeutically addressed as protective targets of renal function and structure after IR. (C) 2011 Elsevier B.V. All rights reserved.

Macrophage-independent T cell infiltration to the site of injury-induced brain inflammation

We have addressed the role of macrophages in glial response and T cell entry to the CNS after axonal injury, by using intravenous injection of clodronate-loaded mannosylated liposomes, in C57BL6 mice. As expected, clodronate-liposome treatment resulted in depletion of peripheral macrophages which was confirmed by F4/80- and MOMA-1(-) stainings in spleen. Sequential clodronate-liposome treatment 4, 2 and 0 days before axotomy resulted in significant reduction of infiltrating CD45(high) CD11b+ macrophages in the hippocampus at 1, 2 and 3 days post-lesion, measured by flow cytometry. There was a slight delay in the expansion of CD45(dim) CD11+ microglia in clodronate-liposome treated mice, but macrophage depletion had no effect on the percentage of infiltrating T cells in the lesion-reactive hippocampus. Lesion-induced TNFalpha mRNA expression was not affected by macrophage depletion, suggesting that activated glial cells are the primary source of this cytokine in the axonal injury-reactive brain. This identifies a potentially important distinction from inflammatory autoimmune infiltration in EAE, where macrophages are a prominent source of TNFalpha and their depletion prevents parenchymal T cell infiltration and disease.

Injury prevention in Queensland : report to Queensland Injury Prevention Council

Injury is the fourth leading cause of death in Australia. Injury rates in Queensland are amongst the highest in Australia and 21.5% of people surveyed for this research reported that their lifestyle or that of an immediate family member had been permanently affected by injury. Injury results in over 40,000 hospital admissions and 200,000 attendances at hospital Emergency Departments in Queensland each year. Queensland's death rate from injuries is higher than the national average, with consistently higher rates of deaths related to transport injuries. Queensland statistics also show higher than national average rates of injuries due to falls, homicide and accidental drowning. (Pike, Muller, Baade & Ward, 2000) In 2000-01 injuries represented over $4 billion (or 8%) of total health system expenditure, and 185,000 disability-adjusted life years (DALYs), or 7% of the total morbidity burden of disease and injury in Australia in 2003. (Begg, Vos, Barker, Stevenson, Stanley & Lopez, 2007). Injury is one of seven key health areas identified by the Commonwealth, state and territory governments for priority attention as National Health Priority Areas

Teaching young people first aid skills to reduce injury

Background First aid given immediately after a motor vehicle crash can have considerable benefits. Less understood however is first aid training as a prevention strategy for reducing risk-taking. A first step is to understand whether first aid skills are associated with risk-taking and injury experiences. Further, students and teachers who undergo or deliver such training offer important perspectives about implementation. Aims The research has two aims: (i) to identify whether first aid knowledge is associated with road risk-taking and injury and (ii) to examine teachers’ and students’ experiences of first aid activities within a school-based injury prevention and control program. Method Participants were 173 Year 9s (47% male) who completed a survey which included demographic information, first aid knowledge and risk-taking behaviour and injury experiences. Focus groups were held with 8 teachers who delivered, and 70 students who participated in, a school-based injury prevention and control program. Results Results showed a relationship between greater first aid knowledge and reduced engagement in risk-taking and injury experiences. Both students and teachers reported favourably on first aid however teachers also acknowledged challenges in delivering practical activities. Discussion & Conclusion It appears that first aid can be implemented within the school setting, particularly at the Year 9 level, and that both students and teachers involved in such training identify multiple benefits and positive experiences with first aid training. In addition, the findings suggest that first aid knowledge could be an important part of a prevention program.

Reduction of Secondary Degeneration after Spinal Cord Injury by Acute Delivery of Proinflammatory Growth Factors

INTRODUCTION Inflammation is a protective attempt to facilitate the removal of damaged tissue and to initiate the healing response in other tissues. However, after spinal cord injury (SCI), this response is prolonged leading to secondary degeneration and glial scarring. Here, we investigate the potential of sustained delivery of pro-inflammatory factors vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) to increase early inflammatory events and promote inflammatory resolution. Method Animal ethics approval was obtained from the Queensland University of Technology. Adult Wistar-Kyoto rats (12-16 weeks old) were subjected to laminectomies and T10 hemisections. Animals were then randomised to treatment (implantation of osmotic pump (Alzet) loaded with 5ug VEGF & 5 ug PDGF) or control groups (lesion control or lesion plus pump delivering PBS). Rats were sacrificed at one month and the spinal cords were harvested and examined by immunohistology, using anti-neurofilament-200(NF200) and anti- ionized calcium binding adapter molecule 1 (Iba1). One way ANOVA was used for statistic analysis. Results At 1 month, active pump-treated cords showed a high level of axonal filament throughout the defects as compared to the control groups. The mean lesion size, as measured by NF200, was 0.47mm2 for the lesion control, 0.39mm2 for the vehicle control and 0.078mm2 for the active pump group. Significant differences were detected between the active pump group and the two control groups (AP vs LC p= 0.017 AG vs VC p= 0.004). Iba-1 staining also showed significant differences in the post-injury inflammatory response. Discussion We have shown that axons and activated microglia are co-located in the lesion of the treated cord. We hypothesise the delivery of VEGF/PDGF increases the local vessel permeability to inflammatory cells and activates these along with the resident microglia to threshold population, which ultimately resolved the prolonged inflammation. Here, we have shown that maintaining the inflammatory signals for at least 7 days improved the morphology of the injured cord. Conclusion This study has shown that boosting inflammation, by delivery VEGF/PDGF, in the early phase of SCI helps to reduce secondary degeneration and may promote inflammation resolution. This treatment may provide a platform for other neuro-regenrative therapies.

Targeting injury prevention strategies to adolescents of Pacific Islander descent : what will work?

Background: Ethnicity is rarely considered in injury prevention program development, even though this is known to impact on participation in injury risk behaviour. An understanding of injury, risk behaviour and risk and protective factors specific to adolescents of Pacific Islander descent will inform the development of prevention strategies appropriate to this group.----- Aims: To determine patterns of injury and associated risk behaviour among adolescents of Pacific Islander descent, and to understand the risk and protective factors that influence injury rates among this group.----- Methods: A total of 875 Year 9 students from five Queensland high schools completed a survey during health classes. Seventy-one students (n = 38 male) identified as Pacific Islander. The survey consisted of scales examining injury, risk taking behaviour, and relationships with family, school and police.----- Results: The leading causes of injury among adolescents of Pacific Islander descent were sports (48%) and transport (e.g. 45% reported bicycle injuries). Interpersonal violence related injuries were also relatively frequent, with 28% having been injured in a fight. Reports of alcohol use were relatively low (20% c.f. 40% of the remaining sample), however reports of other risk behaviours were relatively high (e.g. 43% c.f. 25% of remaining sample reported a group fight).----- Discussion and conclusions: Conclusions will be drawn regarding risk-related injuries reported by adolescents of Pacific Islander descent and those of other ethnic backgrounds. Additionally, risk and protective factors relating to family, school and police will be explored, in order to inform prevention strategies appropriate to this group.

The importance of school connectedness in adolescent risk taking and injury prevention

Background: Injury is the leading cause of mortality for young people in Australia (AIHW, 2008). Adolescent injury mortality is consistently associated with risk taking behaviour, including transport and interpersonal violence (AIHW, 2003), which often occurs in the context of alcohol and other substance use. A rapid increase in risk taking and injury through early to late adolescence highlights the need for effective school based interventions. Aim: The aim of the current research was to examine the relationship between school connectedness and adolescent risk and injury, in order to inform effective prevention approaches. School connectedness, or students’ feelings of belongingness to school, has been shown to be a critical protective factor in adolescence which can be targeted effectively through teacher interventions. Despite evidence linking low school connectedness with increased health risk behaviour, including substance use and violence, research has not yet addressed possible links between connectedness and a broader range of risk taking behaviours (e.g. transport risks) or injury. Method: This study involved background data collection to inform the development of an intervention. A total of 595 Year 9 students (aged 13-14 years) from 5 Southeast Queensland high schools completed questionnaires that included measures of school connectedness, risk taking behaviour, alcohol and other substance use, and injuries. Results: Increased school connectedness was found to be associated with fewer transport risk behaviours and with decreased alcohol and other substance use for both males and females. Similarly, increased school connectedness was associated with fewer passenger and motorcycle injuries for male participants. Both males and females with increased school connectedness reported fewer alcohol related injuries. Implications: These results indicate that school connectedness appears to have protective effects for early adolescence. These findings may also hold for older adolescents and indicate that it may be an important factor to target in school based risk and injury prevention programs. A school connectedness intervention is currently being designed, focusing on teacher professional development. The intervention will be implemented in conjunction with a curriculum based injury prevention program for Year 9 students and will be evaluated through a large scale cluster randomised trial involving 26 schools.