Mitigation of secondary disease in mice receiving bone marrow from donors pretreated with cortisone and alkylating agents.
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BACKGROUND: In the acute rejection of allografts, the interaction between Fas (CD95) and its ligand (FasL; CD95L) has been shown to be involved in mediating apoptotic cell death. The role, however, of these molecules in the pathogenesis of transplant vascular sclerosis is as yet undetermined. The present study was therefore designed to address this issue. MATERIAL: C3H/HEJ FasLgld (FasL-; H2k) spontaneously mutant mice were used either as donors or recipients of aortic allografts; wild-type C57B1/6 (B6; H2b) were used as corresponding recipients or donors (n=6/group), respectively. Controls included aortas transplanted across appropriate allogeneic and syngeneic strain combinations. For histopathological evaluations, the grafts were harvested at day 40 after transplantation, at which time, splenocytes and sera were also obtained for mixed leukocyte reaction and complement-mediated microcytotoxicity assays, respectively. RESULTS: Similar to aortas obtained from allogeneic controls, allografts harvested from FasL- -->B6 recipients had morphological evidence of chronic rejection characterized by circumferential intimal thickening with partial disruption of the elastic membranes. Correspondingly, heightened antidonor cellular reactivity was also witnessed in these recipients. On the contrary, B6 allografts harvested from the majority of C3H-->FasL- recipients exhibited marked preservation of aortic morphology. Although these recipients had diminished antidonor cellular proliferation, the titers of alloantibodies were markedly elevated. CONCLUSION: The presence of FasL-expressing functional cytotoxic T cells is required for the pathogenesis of transplant vascular sclerosis. The significant reduction and/or absence of chronic rejection with the concomitant retention of antidonor humoral response in C3H FasL- recipients of B6 aortas prompt us to suggest that perhaps posttransplantation vasculopathy is initiated by cell-mediated cytotoxicity with its perpetuation facilitated by alloantibodies.
BACKGROUND: Preretrieval warm ischemic injury predisposes to both short-term and long-term dysfunction of cadaveric renal allografts. We previously reported that the excretion of the vasoactive peptide, endothelin (ET), is significantly increased during hypothermic perfusion preservation (HPP) of kidneys subjected to preretrieval warm ischemia compared with nonischemic controls. As such, the purpose of this study was to determine if endothelin receptor (ET-R) blockade during HPP would improve glomerular filtration rate (GFR) of kidneys subjected to preretrieval warm ischemia when measured in situ at 2 weeks after transplantation (Tx). METHODS: The left kidney was retrieved from 300-g Lewis rats after in situ cold perfusion and transplanted after 2 hr of HPP. A 30-min period of preretrieval warm ischemia was induced. Kidneys were divided into four groups: nonischemic controls (n=9), ischemic (isch) kidneys not receiving ET-R blockade during HPP (n=7), isch kidneys receiving the ETA receptor antagonist (n=7), and isch kidneys receiving the ETA/B receptor antagonist (n=8). ET-R blockade was induced by adding the ETA, A-147627, or the ETA/B, A-182086, receptor antagonist (Abbott Laboratories, Abbott Park, IL) directly to the preservation solution (5x10-6M). The kidneys were then isografted into genetically identical Lewis rats and GFR, determined by measurement of urinary iohexol clearance, measured 2 weeks after Tx. RESULTS: Two-week GFRs (mL/min) for each of the study cohorts are as follows: nonischemic controls, 1.18+/-0.11; ischemic (isch) only, 0.57+/-0.08 (P< or =0.05 vs. nonischemic controls); isch + ETA blockade, 0.95+/-0.15 (P< or =0.05 vs. isch only); isch + ETA/B blockade, 0.90+/-0.08 (P< or =0.05 vs. isch only). CONCLUSION: Addition of an ETA, A-147627, or an ETA/B, A-182086, receptor antagonist to preservation solution used during HPP of kidneys subjected to preretrieval warm ischemia resulted in a normalization of GFR measured 2 weeks after Tx. The data provide a basis for further investigation of the impact of ET-R blockade on both the short- and long-term adverse effects of preretrieval warm ischemic injury in cadaveric renal Tx.
Septic shock is characterized by a decrease in systemic vascular resistance. Nevertheless, regional increases in vascular resistance can occur that may predispose mammals to organ dysfunction, including the acute respiratory distress syndrome. In the host infected by endotoxin (lipopolysaccharide, LPS), the expression and release of proinflammatory tumor necrosis factor-alpha (TNFalpha) rapidly increases, and this cytokine production is regulated by agents elevating cyclic AMP. In this report, we present evidence that terbutaline, a beta2-agonist, inhibits TNFalpha production and enhances interleukin-10 (IL-10) release in the anesthetized rat treated with LPS. In addition, an overproduction of nitric oxide (NO, examined by its metabolites nitrite/nitrate) by inducible NO synthase (iNOS, examined by western blot analysis) is attenuated by pretreatment of LPS rats with terbutaline. Overall, pretreatment of rats with terbutaline attenuates the delayed hypotension and prevents vascular hyporeactivity to norepinephrine. In addition, pretreatment of mice with terbutaline also improves the survival in a model of severe endotoxemia. The infiltration of polymorphonuclear neutrophils into organs (e.g., lung and liver) from the surviving LPS mice treated with terbutaline was reduced almost to that seen in the normal controls. These findings suggest that the inhibition of TNFalpha and NO (via iNOS) production as well as the increment of IL-10 production contribute to the beneficial effect of terbutaline in animals with endotoxic shock.
BACKGROUND: Leaving the hospital against medical advice has been associated with increased morbidity and readmission. Factors associated with the risk of leaving against medical advice among HIV/AIDS patients or injection drug users have not been examined in detail. OBJECTIVES: To examine the clinical and social factors associated with leaving against medical advice (AMA) from a specialized HIV/AIDS ward among patients who reported a history of injection drug use. METHODS: All patients with a history of injection drug use admitted to the HIV/AIDS ward at St. Paul's Hospital, Vancouver, British Columbia (the largest specialized HIV/AIDS hospital ward in Canada) between April 1997 and October 2000 were reviewed retrospectively. A multivariate logistic regression model utilizing a generalized estimating equation algorithm identified factors associated with leaving the hospital AMA. RESULTS: Of the 1056 hospital admissions to the HIV/AIDS ward by patients with a history of injection drug use, 263 (24.9%) resulted in leaving the hospital AMA. Independent positive predictors of leaving AMA included recent injection drug use (adjusted odds ratio [AOR] = 2.08, 95% confidence interval [CI]: 1.41-3.07) and aboriginal ethnicity (AOR = 1.55, 95% CI: 1.05-2.28). Discharge AMA was also more likely to occur on weekends (AOR = 2.27, 95% CI: 1.49-3.48) and on days when social assistance payments were issued (AOR = 2.95, 95% CI: 1.70-5.10). Factors that independently reduced the odds of hospital discharge AMA included in-hospital methadone use (AOR = 0.49, 95% CI: 0.32-0.76), social support (AOR = 0.33, 95% CI: 0.21-0.51), and older age (per 10-year increment, AOR = 0.56, 95% CI: 0.43-0.73). CONCLUSIONS: Among HIV-positive patients with a history of injection drug use, the odds of leaving the hospital AMA were reduced for subjects who received inpatient methadone treatment, were of older age, or had social supports. Addiction treatment and interventions that enhance social supports in marginalized populations at risk for hospital discharge AMA should be further explored.
Liver ischemia and subsequent reperfusion (IR) are associated with secondary, remote organ reperfusion injury attributable to oxidative stress mediators. Because N-acetyl-L-cysteine (NAC) was effective in attenuating lung reperfusion injury, its properties on aortic dysfunction were tested. Rat isolated perfused aortic rings (n = 8/group) were evaluated during and after exposure to liver postischemia perfusate. Aortic response to phenylephrine under these conditions was also assessed in the presence or absence of increasing concentrations of NAC. Aortic rings incubated with postischemia perfusates exhibited abnormally protracted contraction. Their response to phenylephrine was reduced to 18 +/- 7% and 65 +/- 11% of controls during and after the exposure, respectively, and their subsequent relaxation was irregular. NAC 0.25 mM best attenuated the IR-induced aortic tone impairments, 0.12 mM affected it slightly, and IR-NAC 0.5 mM and IR-NAC 0.74 mM solutions dilated the rings proportionately, abolishing reactions to both IR solutions and phenylephrine. Xanthine oxidase activity and reduced glutathione (GSH) level in all IR ring tissues were inversely proportionate, but not directly so. Thus, liver IR impaired aortic tone and its response to phenylephrine, even after removal of toxic elements. NAC concentrations directly and inversely correlated with xanthine oxidase activity but not with GSH level. It preserved aortic functions dose-specifically, mainly by oxidant quenching.
OBJECTIVE: To assess the role of sexually transmitted infection (STI) management to prevent HIV acquisition among sex workers in Burkina Faso. DESIGN: Open cohort study of professional and nonprofessional sex workers with 3-month follow-up visits. METHODS: Baseline and follow-up visits consisted of the administration of a behavioral questionnaire, education sessions on HIV and STIs, a medical examination, and laboratory testing for STI and HIV diagnosis. RESULTS: Three hundred seventy-seven HIV-negative women were enrolled in the study. The cumulated HIV incidence was 3.2 per 100 person-years (Poisson 95% confidence interval: 1.9-4.9). Bacterial and parasitic STIs were low at baseline, whereas herpes simplex virus-2 (HSV-2) prevalence was 54.7%. By a Cox regression model, self-assessment of high HIV risk in the past, less than 5 clients per week, and no change of a steady partner were independently associated with HIV acquisition. Among STIs, only infection with HSV-2 tended to be associated with HIV acquisition (odds ratio = 2.45; P = 0.15). Overall, condom use increased during the study but to a lesser extent with steady partners. CONCLUSIONS: Bacterial and parasitic STIs are no longer a key determinant of HIV acquisition, given the current stage of the outbreak in Burkina Faso. Although efforts for STI control should be maintained, strategies should focus on nonprofessional sex workers, steady partners, and HSV-2 infection to tackle HIV transmission further in this high-risk group.
BACKGROUND: Chronic alcohol consumption leads to lipid accumulation, oxidative stress, cellular damage, and inflammation in the liver, collectively referred to as alcohol-associated liver disease (ALD). FAF2/UBXD8/ETEA (Fas-associated factor 2) is a ubiquitin ligase adaptor protein that plays a crucial role in the ubiquitin-mediated degradation of misfolded proteins in the endoplasmic reticulum. A recent genome-wide association study indicated an association between FAF2 and ALD; however, the exact contribution of FAF2 to ALD pathogenesis remains unclear. METHODS: FAF2 was knocked down using AAV-delivered shRNA in C57/BL6 mice. Mice were subjected to a chronic-plus-single binge ethanol feeding (NIAAA) model. Nine hours after gavage, liver, blood, and other organs of interest were collected for gene expression and biochemical analyses. RESULTS: We first observed a significant elevation in hepatic FAF2 protein expression in individuals with ALD and in mice subjected to an ethanol-binge model. Interestingly, knocking down FAF2 in the liver using adeno-associated virus serotype 8-delivered short hairpin RNA conferred a protective effect against alcohol-induced liver steatosis in ethanol-binged mice. Transcriptomic analysis revealed that differentially expressed genes were enriched in multiple lipid metabolism regulation pathways. Further analysis of transcription factors regulating these differentially expressed genes suggested potential regulation by SREBP1. Several SREBP1 target genes, including Fasn, Scd1, Lpin1, and Pcsk9 (proprotein convertase subtilisin/kexin type 9), were dysregulated in the livers of ethanol-fed FAF2 knockdown mice. Additionally, Pcsk9 could be regulated through the FOXO3-SIRT6 pathway in the livers of ethanol-fed FAF2 knockdown mice, leading to increased liver low-density lipoprotein receptor expression and reduced plasma LDL cholesterol levels. Furthermore, FAF2 knockdown in mouse liver enhanced adipose triglyceride lipase lipolytic activity by upregulating the adipose triglyceride lipase activator, comparative gene identification-58, and downregulating the adipose triglyceridelipase transport inhibitor, Elmod2, contributing to the alleviation of liver steatosis. CONCLUSIONS: Our study uncovers a novel mechanism involving FAF2 in the pathogenesis of ALD.
BACKGROUND: Hyperlipidemia is a recognized complication of HIV antiretroviral therapy. The interactions between HIV, hepatitis C virus (HCV), antiretroviral agents and lipids are not well understood. METHODS: We evaluated the lipid data of patients receiving antiretroviral therapy at the Ottawa Hospital Immunodeficiency Clinic between January 1996 and June 2005 using a clinic database. RESULTS: A total of 357 HIV-mono-infected and 115 HIV/HCV-co-infected patients were evaluated. The mean changes in total cholesterol (mmol/l) from baseline to months 6 and 12 were 1.00 and 1.24 in HIV mono-infection, and 0.19 (P < 0.001) and 0.01 (P < 0.001) in HIV/HCV, respectively. Metabolic complications including hypercholesterolemia resulted in the interruption of HAART in HIV mono-infection (8%), but not in those with HIV/HCV (< 1%; P < 0.001). Eight per cent of HIV-mono-infected and no co-infected patients initiated lipid-lowering therapy while on their initial course of HAART (P < 0.001). Total cholesterol increased by 0.85 mmol/l in HIV/HCV-co-infected recipients of interferon-based HCV treatment achieving a sustained virological response (SVR), but did not change in those who did not achieve a SVR. CONCLUSION: HCV co-infection appears to confer a degree of protection from HAART-related lipid complications. The mechanism of this finding deserves evaluation. The implications of this observation for long-term cardiovascular disease risk remains a pressing issue.
A major concern about land use, land-use change and forestry (LULUCF) projects under the Clean Development Mechanism (CDM) is the potential for leakage. Leakage refers to a net increase of greenhouse-gas emissions in an area outside the project resulting from the CDM activity. This paper provides an overview of leakage, its definitions and its causes. It describes ways that LULUCF projects may suffer from leakage and attempts to assess the magnitude of leakage risks for different LULUCF project types. It also summarizes some of the approaches, both in terms of policies and project development, to address LULUCF leakage.
The management of marine fisheries needs to undergo dramatic change in the new millennium, in response to the well-documented evidence of global overfishing and the general depletion of commercial fish stocks. The axioms of sustainable development and equilibrium productivity of wild ecosystems are identified as misleading concepts, which nonetheless underlie current approaches to the management of living marine resources. Current trends in marine fisheries landings worldwide provide little evidence of sustainability of marine resources under current management paradigms, where biological, economic and social aspects of fisheries are usually treated as different disciplines. While open-access conditions are less widespread than formerly, except for many straddling and highly migratory resources, fishers usually have access to the resource year-round throughout its range. Despite quotas, the nominal control of capacity and technical measures protecting juveniles, top-down management has generally been unable to prevent stock depletion, particularly of the older spawners that for demersal stocks often support recruitment. An integrated solution to the complexity of managing wild resources seems not to have been achieved. Any new paradigm should assert the basic unpredictability of fisheries at the system level and require a broader range of performance indicators to be incorporated into the decisional framework. This must reflect the non-equilibrium nature of marine systems, and give greater importance to resource (as opposed to harvest) continuity in the face of regime shifts, and promote habitat restoration and conservation of genetic resources. The new management framework requires co-management and collective decision-making to be incorporated within a precautionary and pre-negotiated management framework. This must explicitly recognize that decision-making occurs in conditions of model-based uncertainty and precautionary approaches should be incorporated at all levels, not least of which is to avoid the assumption that all resources can be harvested in a sustainable fashion through time. Redundancy in data inputs to management are needed to avoid the surprises that model-based sampling occasionally leads to, for example, when regime changes reduce productivity in response to climatic fluctuations. Emergency frameworks imposing non-discretionary rules must be invoked when overfishing and/or regime change trigger reference points indicating stock depletion. Non-discretionary recovery plans should then override rights-based systems and persist until fish populations recover to pre-established healthy levels, which may in turn need to await the return of a favourable regime. In fact, some stocks may require periodic rebuilding after regime-induced collapses or because of a combination of ecological or economic impacts, hence a constant harvest policy may not always be possible. It will probably also be necessary to discard the axiom that a stock should be available to harvesting throughout its range and seasonal cycle. Technological advances mean that time- and area-specific access rights are now practical options, through satellite monitoring of vessel operations, even offshore. More fundamentally, the basic axiom of "enlightened self interest" underlying current methods of management will need to be tempered by an increased ethical concern for the fragility of natural ecosystems.
The unusual early synthesis of the Autographa californica M nucleopolyhedrovirus (AcMNPV) budded virus (BV) structural protein GP64 is an important virulence factor during oral infection of Heliothis virescens larvae. Considering the breadth of the AcMNPV host range, the importance of early GP64 synthesis in orally infected permissive hosts (Trichoplusia ni and Spodoptera exigua) from subfamilies other than that of H. virescens was assessed. An AcMNPV recombinant, having wild-type early and late GP64 synthesis, was compared with one in which only late GP64 synthesis occurred. Early GP64 synthesis was found to have more of an effect on virulence in orally inoculated T. ni than S. exigua and that virulence was dependent on two factors: the ability of the host to slough occlusion-derived virus (ODV)-infected midgut cells and the rapidity with which BV was transmitted to the tracheal cells. In both host species, insects inoculated orally with the control virus transmitted BV to tracheal cells hours before those inoculated with the gp64 temporal mutant. Moreover, with early GP64 synthesis, the lag between the onset of viral gene expression in midgut and tracheal cells was only 3-4 h, supporting the conclusion that in these insects, the first systemic infections arose from ODV-derived nucleocapsids repackaged as BV. These results provide further empirical proof that early GP64 synthesis is a component of a unique and selectively advantageous baculovirus infection strategy for exploiting larval lepidopterans by counteracting developmental resistance.
Cellular senescence contributes to aging and age-related diseases by driving chronic inflammation through the Senescence Associated Secretory Phenotype (SASP) and interferon-stimulated genes (ISGs). Cyclin D1 (CCND1), a key cell cycle regulator, is paradoxically upregulated in these non-proliferating cells. We show that CCND1 and its kinase partner CDK6 drive SASP and ISG expression in senescent cells by promoting DNA damage accumulation. This leads to the formation of cytoplasmic chromatin fragments (CCFs) that activate pro-inflammatory CGAS-STING signaling. The tumor suppressor p53 (TP53) and its target p21 (CDKN2A) antagonize this CCND1-CDK6-dependent DNA damage accumulation pathway to suppress the SASP. In aged mouse livers, senescent hepatocytes show increased Ccnd1 expression. Hepatocyte-specific Ccnd1 knockout or treatment with the Cdk4/6 inhibitor Palbociclib reduces DNA damage and ISGs in aged mouse liver. Notably, Palbociclib also suppresses frailty and improves physical performance of aged mice. These findings reveal a novel role for CCND1/CDK6 in regulating DNA damage and inflammation in senescence and aging, highlighting it as a promising therapeutic target.
Current methods of free R factor cross-validation assume that the structure factors of the test and working sets are independent of one another. This assumption is only an approximation when the modeled structure occupies anything less than the full asymmetric unit. Through progressive elimination of reflections from the working set, starting with those expected to be most correlated to the test set, small biases in free R can be measured, presumably because of over-sampling of the Fourier transform owing to bulk solvent in the crystal. This level of bias may be of little practical importance, but it rises to significant levels with increasing non-crystallographic symmetry owing to wider correlations between structure factors than hitherto appreciated. In the presence of 15-fold non-crystallographic symmetry, with resolutions commonly attainable in macromolecular crystallography, it may not be possible to calculate an unbiased free R factor. Methods are developed for the calculation of reduced-bias free R factors through elimination of the strongest correlations between test and working sets. With 180-fold non-crystallographic symmetry they may not be an accurate indicator of absolute quality, but they do yield the correct optimal weighting for stereochemical restraints.
This paper opens with a history of development and disaster-prevention strategies in a cyclone-prone area of the east coast of India and traces the evolution in the area of British and Indian governments' programmes and policy over a century. Research over the last 20 years has shown, however, that the programmes and policies have failed to balance economic growth with safety. Resources intended for the benefit of all have been diverted by alliances of powerful people to a small minority, and recent developments have reduced the physical protection of the area. The result is that increasing numbers of people are vulnerable to the effects of cyclones and floods. The findings suggest that the best way to reduce vulnerability is to improve the socio-economic standing of the most vulnerable and for this to happen these people must have an assured income based on assets that will enable them to acquire social and economic credit-worthiness within the local economy. This paper presents evidence that suggests that non-governmental organisation (NGO)-supported co-operatives are the best way to achieve this through self-help and self-employment schemes. It also suggests that NGOs should be encouraged to take up environmentally and ecologically beneficial activities involving the poorest groups in the communities, in this way combining sustained self-employment with environmental protection.
Herbivory alters plant gas exchange but the effects depend on the type of leaf damage. In contrast to ectophagous insects, leaf miners, by living inside the leaf tissues, do not affect the integrity of the leaf surface. Thus, the effect of leaf miners on CO2 uptake and water-use efficiency by leaves remains unclear. We explored the impacts of the leaf-mining moth Phyllonorycter blancardella (Lepidoptera: Gracillariidae) on light responses of the apple leaf gas exchanges to determine the balance between the negative effects of reduced photosynthesis and potential positive impacts of increased water-use efficiency (WUE). Gas exchange in intact and mined leaf tissues was measured using an infrared gas analyser. The maximal assimilation rate was slightly reduced but the light response of net photosynthesis was not affected in mined leaf tissues. The transpiration rate was far more affected than the assimilation rate in the mine integument as a result of stomatal closure from moderate to high irradiance level. The WUE was about 200% higher in the mined leaf tissues than in intact leaf portions. Our results illustrate a novel mechanism by which plants might minimize losses from herbivore attacks; via trade-offs between the negative impacts on photosynthesis and the positive effects of increased WUE.
BACKGROUND: We sought to investigate the potential therapeutic effects of acupuncture stimulation of ST-36 (Zusanli) on endotoxemia-induced acute lung injury in lipopolysaccharide (LPS)-stimulated rats. METHODS: Sixty rats were randomized into six groups (n = 10): (i) lipopolysaccharide (LPS) control group, (ii) normal saline (N/S) control group, (iii) LPS plus ST-36 group, (iv) N/S plus ST-36 group, (v) LPS plus sham point (Sham) group, and (vi) N/S plus Sham group. Manual acupuncture stimulation of ST-36 (designated as 'ST-36') or a 'non-acupoint' (designated as 'Sham') was performed in lightly immobilized rats for 30 min. Then, LPS injection was employed to induce sepsis. Rats were killed at 6 h after LPS injection and lung injury, nitric oxide (NO) biosynthesis and inducible NO synthase (iNOS) expression were assayed. RESULTS: Significant lung injury, pulmonary iNOS expression and systemic and pulmonary NO biosynthesis were noted in the LPS groups. Rats in the LPS plus Sham group had lung injury, pulmonary iNOS expression, systemic and pulmonary NO biosynthesis similar to those observed in the LPS group. However, the degree of lung injury, pulmonary iNOS expression and pulmonary NO biosynthesis, but not systemic NO biosynthesis, were significantly attenuated in the LPS plus ST-36 group as compared with those in both the LPS group and the LPS plus Sham group. CONCLUSION: Acupuncture stimulation of ST-36 may be effective as a prophylaxis measure against sepsis. However, results from this study do not support the use of acupuncture for the treatment of sepsis.
Botswana and Sudan experienced consecutive years of drought in the 1980s. Sudan faced a large decline in food entitlement and nutritional deterioration, which translated into famine in 1984/85. Botswana, on the other hand, nearly compensated income losses and averted nutritional deterioration and famine-related deaths. There are important lessons to learn from the famine prevention experience of Botswana. Its strategy for dealing with drought and famine combines policies of steady economic growth with supplementary poverty alleviation and drought relief programs. To provide continuity and stabilization of market operations in times of distress, the country channels sufficient food through market chains, provides price support to preempt market collapse and augments the income of consumers through public income transfer programs to prevent demand failure. In addition, it maintains a responsive and accountable political system and a decentralized participatory administrative structure. While Sudan should develop policies that are compatible with its own environment, it is crucial that it recognizes the critical role of public action in promoting growth, alleviating poverty, and providing timely relief responses in times of anticipated growth failure.