Scottish MDs benefit from database model developed in Saskatchewan.

A data-tracking system developed in Saskatchewan has helped health authorities in Scotland identify some deficiencies in the way certain drugs are prescribed and used. A researcher who published survey results in a local medical journal said the findings have helped doctors improve prescribing practices and identified a need to educate patients about the way antidepressant drugs work.     

Evaluation of copper chelation agents as anti-angiogenic therapy

The design, synthesis and evaluation of N,N',N"-tris(2-pyridylmethyl)-cis,cis-1,3,5,-triaminocyclohexane (tachpyr, 1) derivatives as novel anti-angiogenic agents were performed in an in vitro endothelial cell proliferation assay to assess their cytotoxicity and selectivity. The selective nature of the anti-angiogenic agents for human umbilical vein endothelial cells (Huvec) was compared to a normal fibroblast cell line and a human Glioma cell line to evaluate these compounds. N,N',N"-tris(2-mercaptoethyl)-cis,cis-1,3,5-triaminocyclohexane trihydrochloride (3b) was superior to tachpyr in terms of selectivity of its inhibitory activity toward the proliferation of Huvec compared to the fibroblast and human Glioma cell lines.     

Evaluation of chelating agents as anti-angiogenic therapy through copper chelation

The evaluation of several sets of polyamine donor chelating agents including a selection of novel hexadentate 1,3,5-cis,cis-triaminocyclohexane (tach) based derivatives were performed in an in vitro endothelial cell proliferation assay to assess their cytotoxicity and selectivity as novel anti-angiogenic agents. The selective nature of the anti-angiogenic agents for human umbilical vein endothelial cells (HUVEC) was compared to a normal fibroblast cell line and a human Glioma cell line to evaluate these compounds. Linear tri- and tetra-polyamines were superior to both macrocyclic and the tach based polyamine chelating agents in terms of selectivity of its inhibitory activity toward the proliferation of HUVEC cells compared to the fibroblast and human Glioma cells. The linear polyamine, triethylenetetramine (22), previously reported to possess anti-angiogenic properties failed to demonstrate any selectivity for inhibiting the proliferation of HUVEC cells compared to the fibroblast and human Glioma cells.     

Effective chelation therapy after incorporation of neptunium-239 in rats

It was demonstrated in rats that it is possible to reduce the retention of 239Np in all body tissues by an early combined treatment with small doses of DTPA and DFOA. The content of 239Np can be decreased in soft tissues even if treatment is delayed. Promptly administered LICAM(C) proved more effective than the above chelate combination in reducing 239Np retention in the bones but increased that in the muscles and especially in the kidneys. This side effect of LICAM(C) could be partly prevented by simultaneous treatment with DTPA.     

Metal chelation therapy in rheumathoid arthritis: a case report

Toxic metals are involved in the pathogenesis of some neurodegenerative and vascular diseases and are known to impair the immune system functions. We report here the case of a patient affected by heavy metal intoxication, who had developed an autoimmune disease. There was evidence of aluminium, cadmium and lead intoxication in a 63-year old Italian woman affected by rheumatoid arthritis (RA). We treated the patient with calcium disodium edetate (EDTA) once a week for a year in order to remove traces of heavy metal intoxication. Oxidative status profile was carried out at the beginning and after 6 months’ EDTA chelation. At the end of the treatment, the patient did not show any signs of metal intoxication, RA symptoms and oxidative status improved.     

Synthesis of polyfunctional hydroxamic acids for potential use in iron chelation therapy

Two new multidentate N-methylhydroxamic acids were prepared and characterized. β-Cyclodextrin was esterified by treatment with succinic anhydride. The resulting carboxyl groups (14 per cyclodextrin) were converted to the N-hydroxysuccinimide esters and then on to the hydroxamic acids by treatment with N-methylhydroxylamine. Tetracyanoethylation of cyclohexanone followed by hydrolysis of the nitrile and conversion of the carboxylic acid to hydroxamic acid produced a tetrahydroxamic acid derivative of cyclohexanone. Infrared, ¹H NMR, and ¹³C NMR were consistent with the proposed structures. The hydroxamic acids were water soluble and formed the typical red-brown iron complexes. Stability constants (log K) of 29–30 for the iron complexes indicated a strong chelate effect. Animal tests indicated that the two compounds were only weakly effective in removing iron in vivo from iron-overloaded mice. The potency was only 0.1 that of the standard drug desferrioxamine-B.     

Acute prooxidant effects of vitamin C in EDTA chelation therapy and long-term antioxidant benefits of therapy

Chelation therapy is thought to not only remove contaminating metals but also to decrease free radical production. EDTA chelation therapy, containing high doses of vitamin C as an antioxidant, is often used in the treatment of diseases such as diabetes and cardiovascular diseases but the effectiveness of this treatment may be variable and its efficacy has not been demonstrated conclusively. The objective of this work was to determine if the vitamin C added to standard chelation therapy cocktails was prooxidant. We administered a standard EDTA cocktail solution with or without 5 g of sodium ascorbate. One hour following the standard chelation therapy, there were highly significant prooxidant effects on lipids, proteins, and DNA associated with decreased activities of RBC glutathione peroxidase and superoxide dismutase while in the absence of sodium ascorbate, there were no acute signs of oxidative damage. After 16 sessions of standard chelation therapy, the acute prooxidant effects of vitamin C remained, but, even in the absence of nutrient supplements, there were beneficial long-term antioxidant effects of chelation therapy and plasma peroxide levels decreased. In conclusion, multiple sessions of EDTA chelation therapy protect lipids against oxidative damage. However, standard high amounts of vitamin C added to EDTA chelation solutions also display short term prooxidant effects. The added benefits of lower levels of vitamin C in chelation therapy need to be documented.     

MDs seen as key players in move to encourage active living in Canada

Despite participACTION''s preaching about the need to stay physically active, only a small percentage of Canadians exercise regularly at the level recommended for fitness. Nicole Baer discusses the issue with physicians and experts in the field, and also looks at American efforts to introduce Physician-based Assessment and Counselling for Exercise.     

Genetic or pharmacological iron chelation prevents MPTP-induced neurotoxicity in vivo: a novel therapy for Parkinson's disease

Studies on postmortem brains from Parkinson's patients reveal elevated iron in the substantia nigra (SN). Selective cell death in this brain region is associated with oxidative stress, which may be exacerbated by the presence of excess iron. Whether iron plays a causative role in cell death, however, is controversial. Here, we explore the effects of iron chelation via either transgenic expression of the iron binding protein ferritin or oral administration of the bioavailable metal chelator clioquinol (CQ) on susceptibility to the Parkinson's-inducing agent 1-methyl-4-phenyl-1,2,3,6-tetrapyridine (MPTP). Reduction in reactive iron by either genetic or pharmacological means was found to be well tolerated in animals in our studies and to result in protection against the toxin, suggesting that iron chelation may be an effective therapy for prevention and treatment of the disease.     

Embryonic stem cells remain highly pluripotent following long term expansion as aggregates in suspension bioreactors

Increasing attention has been drawn towards pluripotent embryonic stem cells (ESCs) and their potential use as the primary material in various tissue engineering applications. Successful clinical implementation of this technology would require a quality controlled reproducible culture system for the expansion of the cells to be used in the generation of functional tissues. Recently, we showed that suspension bioreactors could be used in the regulated large-scale expansion of highly pluripotent murine ESCs. The current study illustrates that these bioreactor protocols can be adapted for long term culture and that murine ESC cultures remain highly undifferentiated, when serially passaged in suspension bioreactors for extended periods. Flow cytometry analysis and gene expression profiles of several pluripotency markers, in addition to colony and embryoid body (EB) formation tests were conducted at the start and end of the experiment and all showed that the ESC cultures remained highly undifferentiated over extended culture time in suspension. In vivo teratoma formation and in vitro differentiation into neural, cardiomyocyte, osteoblast and chondrocyte lineages, performed at the end of the long term culture, further supported the presence of functional and undifferentiated ESCs in the expanded population. Overall, this system enables the controlled expansion of highly pluripotent murine ESC populations.     

Temporal changes in free iron levels after brain ischemia Relevance to the timing of iron chelation therapy in stroke

Whereas iron chelators have been proposed as therapeutic agents in stroke, changes in free iron levels have never been explored after focal brain ischemia. Therefore, free and total iron levels in cortical tissue and free iron levels in plasma were measured before and after (1, 4 and 24h) photothrombotic occlusion of cortical vessels in rats. Brain ferritin expression and localization were also investigated before and after (24, 72 and 192 h) occlusion. The results showed that free iron remained below detectable levels in plasma and that the lesion exhibited high levels of free and total iron. As compared to contralateral values, free iron levels in ischemic core and penumbra increased (+50%) at 1h and returned to control values at 4h post-occlusion. In contrast, the increase in total iron levels (+20-30%) was long-lasting, but confined to the ischemic core. A time-dependent increase in the expression of both chains of ferritin was detected in regions that previously exhibited free iron accumulation. Finally, ischemic damage was reduced by the liposoluble iron chelator 2,2'-dipyridyl (20 mg/kg, i.p.) when injected 15 min or 1 h post-occlusion, yet not later (4 h). In conclusion, our results show that focal brain ischemia results in an early and transient elevation in free iron levels in the ischemic tissue and suggest that free iron excess does not originate in blood. They also highlight the importance of starting iron chelation therapy as soon as possible after stroke.     

Combined chelation of lead (II) by deferasirox and deferiprone in rats as biological model

In order to investigate the capability of two chelators deferasirox (DFX or ICL670) and deferiprone (L₁) in removing lead from the body, the present research was performed. Two does levels of 40 and 80 mg/kg body weight of lead (II) chloride was given to rats as biological model for 45 days. After 45 days, some toxicity symptoms were observed in rats such as loss of hair and weight, appearance of red dots around eyes, weakness and irritability. After lead application, chelation therapy with DFX and L₁ as mono and combined (DFX, L₁ and DFX + L₁) was done for 10 days. After chelation therapy, lead level in different tissues reduced. The combined chelation therapy results showed that these chelators are able to remove lead from the body and toxicity symptoms decreased. The combined therapy results (DFX + L1) show higher efficacy and lower toxicity compared to single therapies.     

Evaluation of Nosema locustae (Microsporida) as a control agent of grasshopper populations in Saskatchewan

A quantitative study of the effect of a microsporidan, Nosema locustae, as a control agent against grasshopper populations in Saskatchewan, Canada, revealed that 50% of the populations of Melanoplus sanguinipes, M. packardii, and Camnula pellucida were infected between 4 and 5 weeks (400 to 424 degree-days) after application of the pathogen. Maxima of 95–100% infection were evident between 9 and 12 weeks (600–700 degree-days) after application. The percentage reduction in surviving populations of M. sanguinipes, i.e., those that did not die from natural causes, reached about 20% by the 4th week (400 degree-days) after inoculation, about 50% by the 9th week (600 + degree-days), and a maximum of about 60% by the 12th week (700 degree-days). An exponential relationship was obtained between percentage reduction and percentage infection in all three species. However, a similar percentage infection resulted in different percentage reduction in the populations. Results also revealed that the rate of reduction in populations reached its peak by about 40–80 degree-days before the maximum rate of infection was attained for each species. Egg production in the two Melanoplus species in treated plots was significantly lower (P < 0.05) than in the control plot.     

After fertilization, sperm surface components remain as a patch in sea urchin and mouse embryos

Sea urchin and mouse sperm that are labeled on their surfaces with fluorescein isothiocyanate (FITC), tetramethylrhodamine isothiocyanate (TMRTC) or 125I-diiodofluorescein isothiocyanate (125IFC) remain viable and can fertilize eggs. When sea urchin eggs were fertilized with 125IFC-labeled sperm, the radioactivity from the sperm was quantitatively transferred to the egg (at a ratio of one sperm equivalent per egg) and persisted in the embryo as it developed to the pluteus larval state (5 days at 12 degrees C). The radioactivity was acid-precipitable and was associated with the particulate fraction of embryo homogenates. In addition, FITC-labeled sea urchin sperm were used to fertilize eggs, and the labeled components were followed by fluorescence microscopy. In the embryo, labeled sperm components were present as a discrete patch that was partitioned unequally during early cleavages. In experiments using mouse sperm labeled with TMRTC, the labeled sperm components were also transferred to the embryo as a discrete patch that was again distributed unequally after cleavage. This physiological cell fusion system therefore has distinctive characteristics: there is limited lateral mobility of surface components, which have a low turnover rate unlike that see in other systems. In this paper, we discussed the possible morphogenetic role of this unusual behavior.     

A few-polyhedra mutant and wild-type nucleopolyhedrovirus remain as a stable polymorphism during serial coinfection in Trichoplusia ni

Few-polyhedra (FP) mutants of nucleopolyhedroviruses (NPVs) are a well-known phenomenon during serial passage of virus in cell culture. Under these circumstances such mutants produce low yields of occlusion bodies (OBs) and poorly occlude virions, but they are selected for through advantageous rates of budded virus replication. Spontaneous insertion of transposable elements originating from host cell DNA into the viral fp25 gene has been shown to be a common cause of the phenotype. A model of NPV population genetics predicts that mutants with these characteristics might persist within stable polymorphisms in viral populations during serial passage of virus in vivo. However, this hypothesis was previously untested, and FP mutants have not been recovered from field isolates of NPVs. We isolated and characterized an FP mutant that arose during routine passage of Autographa californica multinucleocapsid NPV (AcMNPV) in cell culture and identified a transposable element within the fp25 gene. We tracked the fates of coinfecting wild-type and FP mutant AcMNPV strains through serial passage in fifth-instar Trichoplusia ni larvae. The levels of both strains remained stable during successive rounds of infection. We applied the data obtained to a model of NPV population genetics in order to derive the frequency distribution of the multiplicity of cell infection in infected insects and estimated that 4.3 baculovirus genomes per OB-producing cell would account for this equilibrium.     

Precipitation, chelation, and the availability of metals as nutrients in anaerobic digestion. I. Methodology

A methodology has been developed for the quantitative assessments of the individual effects of precipitation and chelation of metal ions in an anaerobic digester.