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Nathan Goodyear

Plasma lipoproteins: composition, structure and biochemistry - 0 views

  • triacylglycerols
  • The most abundant lipid constituents are triacylglycerols, free cholesterol, cholesterol esters and phospholipids (phosphatidylcholine and sphingomyelin especially ), though fat-soluble vitamins and anti-oxidants are also transported in this way
  • the lipoprotein aggregates should be described in terms of the different protein components or apoproteins (or 'apolipoproteins'
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  • these classes can be further refined by improved separation procedures, and intermediate-density lipoproteins (IDL) and subdivisions of the HDL (e.g. HDL1, HDL2, HDL3 and so forth
  • Density is determined largely by the relative concentrations of triacylglycerols and proteins and by the diameters of the broadly spherical particles
  • Lipoproteins are spherical (VLDL, LDL, HDL) to discoidal (nascent HDL) in shape with a core of non-polar lipids, triacylglycerols and cholesterol esters, and a surface monolayer, ~20Å thick, consisting of apoproteins, phospholipids and non-esterified cholesterol, which serves to present a hydrophobic face to the aqueous phase
  • the various lipid components should not be considered as absolute, as they are in a state of constant flux
  • Apo A1 is the main protein component of HDL
  • Apo A2 is the second most important HDL apolipoprotein
  • the main groups are classified as chylomicrons (CM), very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL), based on the relative densities of the aggregates on ultracentrifugation
  • The lipoproteins can be categorised simplistically according to their two main metabolic functions. The principal role of the chylomicrons and VLDL is to transport triacylglycerols ‘forward’ as a source of fatty acids from the intestines or liver to the peripheral tissues. In contrast, the HDL remove excess cholesterol from peripheral tissues and deliver it to the liver for excretion in bile in the form of bile acids (‘reverse cholesterol transport’). While these functions are considered separately here for convenience, it should be recognised that the processes are highly complex and inter-related, and they involve transfer of apoproteins, enzymes and lipid constituents among the heterogeneous mix of all the lipoprotein fractions.
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    Awesome review of apolipoproteins, their function, and their metabolism.
Nathan Goodyear

Role of Polymorphic Human Cytochrome P450 Enzymes in Estrone Oxidation - 0 views

  • CYP1A1 and CYP1B1 are not expressed in any significant quantity in the liver. Therefore, they would not be expected to contribute to the overall systemic metabolism of estrone. However, both enzymes have been identified in breast tissue
  • CYP1A1 displayed relatively high activity for all three hydroxylations, suggesting that it may play an important role in extrahepatic tissues where it is expressed
  • CYP1A1 was more active with regard to 2-hydroxylation and 4-hydroxylation, it also displayed one of the greatest 16α-hydroxylating activities of the CYP enzymes tested.
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  • CYP1B1 displayed a high affinity for estrone and preferentially catalyzed 4-hydroxylation over 2-hydroxylation
  • CYP1B1 did not seem to contribute to 16α-hydroxylation.
  • CYP1B1 was shown to preferentially catalyze 4-hydroxylation, whereas CYP1A1 was shown to preferentially catalyze 2-hydroxylation
  • Among the CYP enzymes expressed in the liver, CYP1A2 was the most active with regard to 2-hydroxylation
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    good discussion of estrogen metabolism and the P450 enzymes.
Nathan Goodyear

ScienceDirect - Trends in Immunology : Inflammation: the link between insulin resistanc... - 0 views

  • Inflammation: the link between insulin resistance, obesity and diabetes
  • Chronic overnutrition (obesity) might thus be a proinflammatory state with oxidative stress. Secondly, the increased concentrations of TNF-α and IL-6, associated with obesity and type 2 diabetes, might interfere with insulin action by suppressing insulin signal transduction. This might interfere with the anti-inflammatory effect of insulin, which in turn might promote inflammation.
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    Inflammation: the link between insulin resistance, obesity and diabetes
Nathan Goodyear

Implications of free radicals and antioxidant levels in carcinoma of the breast: A neve... - 0 views

  • Experimental investigations as well as clinical and epidemiological findings have provided evidence supporting the role of reactive oxygen metabolites or free radicals such as singlet oxygen O 2 - , superoxide anions (O 2 ), hydrogen peroxide (H­2 O2 ) and hydroxyl radical in the etiology of cancer.
  • Certain aldehydes such as Malonyldialdehyde (MDA), the end product of lipid peroxidation arising from free radical degeneration of polyunsaturated fatty acids can cause cross linking in lipids, proteins and nucleic acids leading to cellular damage.
  • In this study, patients with cancer exhibited higher levels of MDA, both in tissues and serum (p<0.001) compared to the control group [Table 1]. In tissue, the MDA level in stage IV was significantly higher as compared to stage I indicating increased free radical activity with increasing severity of cancer
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  • From these observations, it can be concluded that MDA levels play an important role in assessing the outcome of cancer
  • SOD and CAT are considered primary antioxidant enzymes, since they are involved in direct elimination of reactive oxygen metabolites. [13-16] They also act as anti-carcinogens and inhibitors at initiation and promotion/transformation stage in carcinogenesis
  • In our study, SOD and CAT levels were found to be low in all cancer patients as compared to controls
  • Fridovich and Tayarani have demonstrated in their respective studies that the reduction in SOD activity increases the toxic effects of O2 - and this might lead to severe cellular damage.
  • Mehrotra et al. in their study also observed high levels of MDA and low levels of SOD and CAT in patients of cancer cervix which is in sync with our observations.
  • strong evidence regarding the definitive role of free radicals in breast malignancy.
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    This study finds a strong correlation between advancing breast cancer, decreased catalase and SOD with increasing MDA.  The authors of this study conclude this is a key factor in carcinogenesis and not a by-product of cancer.  This flies in the face of traditional medicines fear of antioxidant therapy in cancer.
Nathan Goodyear

Lipopolysaccharide (LPS) potentiates hydrogen peroxide toxicity in T98G astrocytoma cel... - 0 views

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    good review of proposed mechanism of how LPS aids in cell death of astrocytes in vivo: LPS damages the endothelium of the BBB, leading to increase permeability.  This exposes astrocytes to LPS directly.  LPS suppressed genetic expression of antioxidant genes.  LPS stimulates cytokine production, including the production of H2O2 from microglial cells in the brain.  An up regulation of iNOS occurs and in the presence of weakened ability to protect against NO and its metabolites occurs.  
Nathan Goodyear

Anti-angiogenic effect of high doses of ascorbic acid - 0 views

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    Vitamin C inhibits angiogenesis via suppression of NO levels.
Nathan Goodyear

Ozone therapy: A clinical review - 0 views

  • Its basic function is to protect humans from harmful effects of UV radiation
  • Its effects are proven, consistent and with minimal side effects
  • Medical O3, used to disinfect and treat disease, has been around for over 150 years
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  • O3 not only remedied infection, but also had hemodynamic and anti-inflammatory properties
  • Stimulation of oxygen metabolism
  • In fungi, O3 inhibits cell growth at certain stages
  • With viruses, the O3 damages the viral capsid and upsets the reproductive cycle by disrupting the virus-to-cell contact with peroxidation.
  • Inactivation of bacteria, viruses, fungi, yeast and protozoa: Ozone therapy disrupts the integrity of the bacterial cell envelope through oxidation of the phospholipids and lipoproteins
  • Activation of the immune system
  • 30 and 55 μg/cc
  • production of interferon and the greatest output of tumor necrosis factor and interleukin-2
  • Mechanism of action of O3 on the human lung
  • cascade of reactions like peroxidation of lipids leading to changes in membrane permeability,[41] lipid ozonation products (LOP) act as signal transducer molecules
  • Dietary antioxidants or free radical scavengers like vitamin E, C, etc., can prevent aforementioned effects of O3
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    Ozone therapy review
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