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PubMed2006

Turbidity mitigates lead toxicity to cladocerans (Cladocera).

To test the hypothesis that sediment would have a synergistic effect on the toxicity of lead to cladocerans, we performed life table demography experiments with two pelagic (Diaphanosoma birgei and Moina micrura) and one littoral (Alona rectangula) cladoceran species. Life table demography experiments were conducted at three levels of turbidity (0, 17 and 170 NTU) and six concentrations of lead (as PbCl2) from 0 to 0.71 mg l(-1). Median lethal concentrations (LC50) forA. rectangula, D. birgei and M. micrura were 7.06 +/- 0.39, 3.16 +/- 0.25 and 3.24 +/- 0.69 mg l(-1) of Pb. Life table study showed that in general, the presence of sediments in test jars allowed an overall increase of 20-75% in both survivorship and reproduction of the cladoceran species exposed to different concentrations of Pb. At 0.04 mg l(-1) of Pb, the population growth rates were 0.127 forA. rectangula, 0.037 for D. birgei and 0.471 d(-1) for M. micrura in the absence of sediments but were elevated in their presence (0.309, 0.141 and 0.722 d(-1), respectively). The data have been discussed in relation to their importance in shallow, turbid Mexican waterbodies.

Animals↗
PubMed2005

Mitigation of oxidative stress in cyclophosphamide-challenged hepatic tissue by DL-alpha-lipoic acid.

The present study investigated the protective effect of DL-alpha-lipoic acid on the tissue peroxidative damage and abnormal antioxidant levels in cyclophosphamide (CP) induced hepatotoxicity. Male Wistar rats of 140 +/- 20 g were categorized into four groups. Two groups were administered CP (15 mg/kg body weight once a week for 10 weeks by oral gavage) to induce hepatotoxicity; one of these groups received lipoic acid treatment (35 mg/kg body weight intraperitoneally once a week for 10 weeks; 24 h prior to the CP administration). A vehicle (saline) treated control group and a lipoic acid drug control group were also included. The extent of liver damage in CP-induced rats was evident from the increased activities of serum aminotransferases, alkaline phosphatase and lactate dehydrogenase; whereas lipoic acid pretreatment prevented the rise in these marker enzymes. We evaluated the changes in activities/levels of tissue enzymic (superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase) and non-enzymic (reduced glutathione, ascorbate and a-tocopherol) antioxidants along with malondialdehyde levels in the experimental groups. In CP-administered rats the antioxidant enzymes showed significantly depressed activities (p < 0.001, p < 0.01) and the antioxidant molecules also showed depleted levels (p < 0.001, p < 0.01), in comparison with the control group. However the extent of lipid peroxidation and the abnormal antioxidant status were normalized in lipoic acid pretreated rats. The present work highlights the efficacy of lipoic acid as a cytoprotectant in CP-induced hepatic oxidative injury.

Animals↗
PubMed2006

Mitigating role of lupeol and lupeol linoleate on hepatic lipemic-oxidative injury and lipoprotein peroxidation in experimental hypercholesterolemia.

In the present study, the role of pentacyclic triterpenes, lupeol and its ester lupeol linoleate, was studied in relation to hepatic oxidative abnormalities and lipoprotein peroxidation in hypercholesterolemic rats. Hypercholesterolemia was induced in male Wistar rats by feeding them with high cholesterol diet (4% cholesterol + 1% cholic acid; HCD) for 30 days. Pentacyclic triterpenes, lupeol and lupeol linoleate were supplemented (50 mg/kg body wt/day) during the last 15 days. After the experimental period, there was a significant depression in hepatic activities of antioxidant enzymes, SOD (38.39%), CAT (25.03%) and GPx (30.26%) along with a marked fall in the levels of non-enzymic antioxidant molecules GSH (31.39%), vitamin C (46.07%) and vitamin E (42.28%), with a concomitant increase (p<0.001) in lipid peroxidation and in the activities of serum alkaline phosphatase, lactate dehydrogenase and aminotransferases when compared to controls. Treatment with triterpenes decreased lipid peroxidation and reverted the activities of antioxidants (p<0.001 and p<0.01) and marker enzymes to near control. Histopathological findings further confirmed the hepatoprotective nature of triterpenes by showing the normal architecture in treated rats, as against the fatty cellular changes in HCD fed rats. Further, the susceptibility of apo-B containing lipoprotein to oxidation by copper and Fenton's reagent was increased in in vitro condition in HCD fed rats, whereas the lipoproteins were less susceptible to oxidation in triterpenes treated animals. Therefore, it may be concluded that lupeol and its ester afford protection against the hepatic abnormalities and lipoprotein peroxidation in hypercholesterolemic rats.

Animals↗
PubMed2002

Dust mite allergens: mitigation and control.

In recent years, greater attention has been given to the role of indoor allergens as a cause of sensitization and allergic respiratory diseases. Although indoor allergen control measures to reduce symptoms in individuals allergic to mites have produced controversial results, environmental allergen avoidance is today one of the four primary goals of asthma management recommended in several guidelines of asthma treatment. Exposure to high indoor aeroallergen levels, especially to house dust mite allergens, is an important environmental risk factor for allergic sensitization and the subsequent development and exacerbation of asthma. Therefore, effective aeroallergen avoidance is of use to prevent and treat allergic diseases. Although endotoxin exposure may be protective in early life, it has been demonstrated that the inhalation of endotoxin may exacerbate asthma in house dust mite sensitized patients. Mite-allergic asthmatic patients should be aware of the dangerous combination of mite allergen exposure associated with high endotoxin levels in house dust. These two immunologically active substances have been associated with severe asthma and seasonal exacerbation of symptoms. Effective house dust mite allergen avoidance will never be achieved using a single control measure; various methods are required to affect the multiple factors that facilitate high indoor allergen levels. Education of the patients and their families is also an important component of environmental control strategies.

Allergens↗
PubMed2002

Ethical and economic issues in the use of zero-emission vehicles as a component of an air-pollution mitigation strategy.

The air pollution generated by motor vehicles and by static sources is, in certain geographic areas, a very serious problem, a problem that exists because of a failure of the marketplace. To address this marketplace failure, the State of California has mandated that by 2003, 10% of the Light-Duty Vehicle Fleet (LDV) be composed of Zero-Emission Vehicles (ZEVs). However, the policy-making process that was utilized to generate the ZEV mandate was problematic and the resulting ZEV mandate is economically unsound. Moreover, an ethical analysis, based primarily upon the work of John Rawls, suggests that implementation of the California ZEV mandate is--in spite of the wide latitude that ought to be given to policy decision makers--unethical. A more ethical and economically efficient approach to the pollution caused by marketplace failure is one that relies on market incentives and thereby achieves the desired improvement in air quality by appealing both to the self-interest of motorists and to those businesses that are directly or indirectly involved with the automobile industry. Such an approach would take better advantage of the creative forces of the market and improvements in technology over time and avoid the infringements on individual liberty and fairness embodied in the ZEV mandate.

Air Pollution↗
PubMed1995

Exogenous NT-3 mitigates the transganglionic neuropeptide Y response to sciatic nerve injury.

Peripheral sciatic nerve transection injury produces a marked increase in immunoreactive NPY in rat lumbar DRG and, as a 'transganglionic' response, in their central axonal projections to the dorsal spinal cord and gracile nuclei. Local application of neurotrophin-3 (NT-3) using implanted silicone chambers applied to the proximal transected sciatic nerve stump significantly diminished the transganglionic NPY response in the gracile nucleus and spinal cord but did not affect the CGRP transganglionic response. Conversely, local application of NGF affected the transganglionic CGRP response to axotomy but did not substantially affect transganglionic gracile NPY upregulation.

Animals↗
PubMed1986

Atherogenesis. Mitigation of monocyte adhesion to arterial endothelium in hyperlipidemic rats by phosphocitrate, a phosphorylated polycarboxylic acid.

Phosphocitrate, a phosphorylated polycarboxylic acid ameliorates two early events in atherogenesis. When administered to rats on an atherosclerotic diet (112 mumol/kg body wt./day), it reduced monocyte adhesion to aortic endothelium from 34 +/- 7 cells/HPF for untreated rats to 1 +/- 1 cell/HPF, a value seen in normal, non-atherosclerotic rats. Transmission electron microscopy of aortic sections showed no evidence of subendothelial lipid accumulation in phosphocitrate-treated rats despite the high circulating plasma lipid levels. The mechanisms of action of phosphocitrate are unknown but the indications are that its influence may be mediated through its polyanionic chemical nature and/or its ability to modulate cellular calcium accumulation. In addition to its possible therapeutic value as an anti-calcifying and anti-atherogenic compound, phosphocitrate may prove useful as an experimental probe for studying the cellular basis of atherogenesis.

Animals↗
PubMed1987

Mitigation of alimentary lipemia by postprandial exercise--phenomena and mechanisms.

The effects of a single bout of exercise at 40% of maximum aerobic capacity with regard to alimentary lipemia and postprandial lipoproteins was studied in a cross-over design in 12 young healthy male volunteers. In addition to lipids and lipoproteins, lipoprotein lipase, free glycerol, free fatty acids, plasma insulin, and C-peptide concentrations were quantitated. Postprandial exercise reduced alimentary lipemia by 34% while lipoprotein lipase activity rose by 42%. The postprandial fall of high-density lipoprotein (HDL)3 was abolished and the rise of HDL2 accentuated. Free glycerol and free fatty acid concentrations were higher following the meal plus exercise regimen compared to the meal alone. It is concluded that at least part of the chronic effect of exercise may come from additive effects such as observed from individual bouts of muscular activity.

Adult↗
PubMed1987

Effects of intranasal ZnSO4 irrigation are mitigated by the presence of untreated littermates.

Observable anomalies were produced in spiny mouse neonates and weanlings through intranasal irrigation with ZnSO4 solution. In comparison to control animals, ZnSO4-treated pups displayed growth retardation, increased mortality rates, hyperactivity in a novel environment and difficulty in finding hidden food pellets. Each of these experimentally-induced deficits was alleviated when treated pups were housed and tested in the presence of intact littermates. The early social environment exerts marked influences on behavioral and physiological development and, if optimal, can buffer pups from the adverse effects of early physical insults.

Administration, Intranasal↗
PubMed1992

Pimozide mitigates excessive running in the activity-stress paradigm.

The present study investigated the role of dopamine in the maintenance of behaviors observed in the activity-stress paradigm. In Experiment 1, several doses (0, 0.125, 0.25, 0.50, and 1.0 mg/kg) of the dopamine D2-receptor blocker, pimozide, were administered to rats maintained on an ad lib feeding schedule. Results indicated that 0.25 mg/kg pimozide did not disrupt running activity when compared to control animals. In Experiment 2, injections of either 0, 0.25, or 0.50 mg/kg pimozide were given every 12 hours to rats subjected to the activity-stress paradigm. Although 0.25 mg/kg pimozide had no effect on dark-phase activity, it significantly suppressed light-phase activity and subsequently increased the number of survivors in the paradigm. It was concluded that dopamine plays a role in maintaining high running levels in the activity-stress paradigm.

Animals↗
PubMedDate not supplied

Septal rage: mitigation by pre-surgical treatment with p-chlorophenylalamine.

Destruction of the septum leads to a well known hyperirritability syndrome. However, the intensity of this syndrome is modifiable by certain presurgical treatments. Injections, prior to surgery of para-chlorophenylalanine (PCPA) for two days or insulin for five days has no effect on septal rage. However, injections of PCPA five days prior to surgery leads to a marked reduction in septal hyperirritability.

Anger↗
PubMed1992

Ribavirin mitigates wart growth in rabbits at early stages of infection with cottontail rabbit papillomavirus.

The challenge to develop antiviral agents effective against DNA viruses such as human papillomavirus (HPV) has been dependent on finding an animal model which mimics the human forms of the disease. We have used an existing model system for the purpose of measuring the effect of antiviral drugs on the inhibition of growth of these lesions. This was based upon domestic rabbits which efficiently grow cutaneous papillomas (warts) when infected with cottontail rabbit papillomavirus (CRPV). One agent which had shown significant success in achieving these goals was ribavirin. Ribavirin was administered intradermally shortly prior to infection at multiple sites with CRPV. Following daily injections of this drug for eight weeks, we have shown a dose-dependent response which had markedly reduced the number of warts, the time of first appearance of warts and reduced the tumor mass as compared to placebo-treated control animals. At the highest dose of ribavirin tested, 30 mg/kg/day, compared to controls, the average reduction in the number of warts was 52%, the average time of first appearance of warts was 49% longer, and the average mass of the warts was reduced by 98%. No detectable antibodies to CRPV were observed in any of the animals. The only side effects which were observed was focal alopecia, and a decrease in body growth upon prolonged treatment, both of which were completely reversible. Pharmacokinetic studies established the metabolism of ribavirin over a 24-h period of time. Ribavirin administered beginning 12 or 30 days post-infection, while not reducing the number of warts, slightly retarded the growth of warts as determined by date of first appearance of warts and mass of warts.

Animals↗
PubMed1989

An assessment of botanical air purification as a formaldehyde mitigation measure under dynamic laboratory chamber conditions.

This study was designed to determine the effectiveness of spider plants (Clorophytum elatum var. vittatium) as a botanical air purification measure for formaldehyde under dynamic laboratory chamber conditions. Significant reductions in chamber formaldehyde levels were observed when spider plants were placed in experimental chambers. However, highest reductions occurred when spider plants were defoliated. Observed reductions in formaldehyde levels appeared to have been associated with soil medium factors and a source moisture storage phenomenon associated with the use of particleboard as a formaldehyde source inside the chambers. The results of this study do not support the conclusions of previous studies which suggest that botanical air purification using only plant leaves is an effective means of reducing residential formaldehyde levels.

Journal Article↗
PubMed1986

Radiation protection problems for the space station and approaches to their mitigation.

With the advent of a permanent manned space station the longstanding problems of radiation protection in manned spaceflight have acquired an immediacy. This paper endeavors to emphasize the gaps of our knowledge which must be closed for effective radiation protection. The information that is required includes the accurate determination of the exposure inside the space station to the various components of tile ionizing radiation, the evaluation of the biological importance of the different radiation qualities and the depth dose distribution of the less penetrating component. There is also the possibility of an interaction with weightlessness. It is necessary to establish adequate radiation protection standards and a system of dosimetric surveillance. There is a need for studies of possible methods of hardening selective shielding of the space station. Spaceflight experiments, which might contribute to the solution of some of these problems are discussed.

Atlantic Ocean↗
PubMed1983

Mitigation of intestinal cytotoxicity of cisplatin by EDTA in rats.

Cisplatin (cis-dichlorodiammineplatinum-II), an antitumor agent containing platinum, produced acute necrotizing enteritis in rats. This toxic side effect was significantly reduced by oral treatment with CaNa2EDTA. The protective effect of CaNa2EDTA against intestinal cytotoxicity of cisplatin was dose-related. Based on histopathological evaluation of cell necrosis and mitotic index, it was estimated that pretreatment with CaNa2EDTA in drinking water (75 mM) and by gavage (1.5 g/kg) prevented intestinal cytotoxicity by up to 90% compared with cisplatin controls.

Acute Disease↗