Cancer Detection in Human Tissue Samples Using a Fiber-Tip pH Probe

Intraoperative detection of tumorous tissue is an important unresolved issue for cancer surgery. Difficulty in differentiating between tissue types commonly results in the requirement for additional surgeries to excise unremoved cancer tissue or alternatively in the removal of excess amounts of healthy tissue. Although pathologic methods exist to determine tissue type during surgery, these methods can compromise postoperative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis, and are restricted to excised tissue. In this work, we report the development of an optical fiber probe that could potentially find use as an aid for margin detection during surgery. A fluorophore-doped polymer coating is deposited on the tip of an optical fiber, which can then be used to record the pH by monitoring the emission spectra from this dye. By measuring the tissue pH and comparing with the values from regular tissue, the tissue type can be determined quickly and accurately. The use of a novel lift-and-measure technique allows for these measurements to be performed without influence from the inherent autofluorescence that commonly affects fluorescence-based measurements on biological samples. The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration, which could find use in the operating theater. Use of this probe in surgery either on excised or in vivo tissue has the potential to improve success rates for complete removal of cancers. Cancer Res; 76(23); 6795-801. ©2016 AACR.

Nonesterified Fatty Acid-Induced Endoplasmic Reticulum Stress in Cattle Cumulus Oocyte Complexes Alters Cell Metabolism and Developmental Competence

Reduced oocyte quality has been associated with poor fertility of high-performance dairy cows during peak lactation, due to negative energy balance. We examined the role of nonesterified fatty acids (NEFAs), known to accumulate within follicular fluid during under- and overnutrition scenarios, in causing endoplasmic reticulum (ER) stress of in vitro maturated cattle cumulus-oocyte complexes (COCs). NEFA concentrations were: palmitic acid (150 μM), oleic acid (200 μM), and steric acid (75 μM). Abattoir-derived COCs were randomly matured for 24 h in the presence of NEFAs and/or an ER stress inhibitor, salubrinal. Total and hatched blastocyst yields were negatively impacted by NEFA treatment compared with controls, but this was reversed by salubrinal. ER stress markers, activating transcription factor 4 (Atf4) and heat shock protein 5 (Hspa5), but not Atf6, were significantly up-regulated by NEFA treatment within whole COCs but reversed by coincubation with salubrinal. Likewise, glucose uptake and lactate production, measured in spent medium samples, showed a similar pattern, suggesting that cumulus cell metabolism is sensitive to NEFAs via an ER stress-mediated process. In contrast, while mitochondrial DNA copy number was recovered in NEFA-treated oocytes, oocyte autofluorescence of the respiratory chain cofactor, FAD, was lower following NEFA treatment of COCs, and this was not reversed by salubrinal, suggesting the negative impact was via reduced mitochondrial function. These results reveal the significance of NEFA-induced ER stress on bovine COC developmental competence, revealing a potential therapeutic target for improving oocyte quality during peak lactation.

Redox and anti-oxidant state within cattle oocytes following in vitro maturation with bone morphogenetic protein 15 and follicle stimulating hormone

The developmental competence of cumulus oocyte complexes (COCs) can be increased during in vitro oocyte maturation with the addition of exogenous oocyte-secreted factors, such as bone morphogenetic protein 15 (BMP15), in combination with hormones. FSH and BMP15, for example, induce different metabolic profiles within COCs-namely, FSH increases glycolysis while BMP15 stimulates FAD and NAD(P)H accumulation within oocytes, without changing the redox ratio. The aim of this study was to investigate if this BMP15-induced NAD(P)H increase was due to de novo NADPH production. Cattle COCs were cultured with FSH and/or recombinant human BMP15, resulting in a significant decrease in glucose-6-phosphate dehydrogenase activity (P < 0.05). Inhibition of isocitrate dehydrogenase (IDH) during this process decreased NAD(P)H intensity threefold in BMP15-treated oocytes, suggesting that BMP15 stimulates IDH and NADPH production via the tricarboxylic acid cycle. As NADPH is a reducing agent, reduced glutathione (GSH), H2O2, and mitochondrial activity were also measured to assess the general redox status of the oocyte. FSH alone decreased GSH levels whereas the combination of BMP15 and FSH sustained higher levels. Expression of genes encoding glutathione-reducing enzymes were also lower in oocytes cultured in the presence of FSH alone. BMP15 supplementation further promoted mitochondrial localization patterns that are consistent with enhanced developmental competence. Metabolomics revealed significant consumption of glutamine and production of alanine by COCs matured with both FSH and BMP15 compared to the control (P < 0.05). Hence, BMP15 supplementation differentially modulates reductive metabolism and mitochondrial localization within the oocyte. In comparison, FSH-stimulation alone decreases the oocytes' ability to regulate cellular stress, and therefore utilizes other mechanisms to improve developmental competence.

Does an ultra violet photooxidation of the manganese-loaded/copper-depleted prion protein in the retina initiate the pathogenesis of TSE?

Ecosystems supporting clusters of sporadic transmissible spongiform encephalopathy (TSE) are characterized by common properties of high-manganese/low-copper, zinc, selenium mineral status, and high-altitude/snow-covered/pre-cambrian mountain terrain where above-average intensities of ultra violet/ozone oxidants are prevalent. Cell culture trials have confirmed the hypothesis that manganese (Mn) substitutes at Prion Protein's (PrP's) vacated copper (Cu) domain, whereupon PrP loses its Cu-mediated antioxidant function, transforming into a protease-resistant misfolded isoform that aggregates into fibril 'tombstone' structures - the key hallmark distinguishing TSE central nervous system (CNS) pathology. The cellular localisation of PrP suggests PrP serves a 'front line' contributory role in neutralizing radicals generated by incoming environmental oxidants, whilst an intensive expression of PrP messenger ribonucleic acid (mRNA) in the retina, melanocytes, epidermis, etc., suggests PrP performs a key antioxidant role as a 'photooxidative shock absorber'; binding of porphyrin IX, Congo red and other photosensitisers to PrPc suggests PrPc serves as an integral associate of the porphyrin/melanin chromophore electron transfer chain; thereby serving as a quencher of singlet O2/superoxide generated by photoenergised chromophores/xeno photosensitisers. It is proposed that sporadic TSE pathogenesis is initiated in the retina of environmentally/genetically predisposed individuals via a two-stage chronic toxic process - Mn substitution at PrP's Cu domain forming a stable Mn2+-PrP complex, followed by an ultra violet in situ photo-oxidization of the Mn2+ component; whereby the latent 'Jekyll and Hyde' capacity of the Mn2+-PrP conjugate is activated into the fully fledged, 'infectious' lethal auto-oxidizing, Mn3+-PrP 'prion' agent. Thus, PrPc's Cu-mediated antioxidant function is replaced by a Mn3+-mediated autooxidant dysfunction. Could the UK's increased loading of a cocktail of environmental oxidants that penetrated the CNS of the UK bovine (ultra violet microwaves/ozone/systemic cu-chelating insecticides) account for a more virulent Mn4+ mediated acceleration of the TSE degenerative process in Mn-contaminated/genetically predisposed individuals, manifesting as the widespread emergence of new-variant bovine spongiform encephalopathy (BSE)/variant Creutzfeldt-Jacob disease (VCJD)/FSE in younger mammals?

Ecosystems supporting clusters of sporadic TSEs demonstrate excesses of the radical-generating divalent cation manganese and deficiencies of antioxidant co factors Cu, Se, Fe, Zn. Does a foreign cation substitution at prion protein's Cu domain initiate TSE?

Analyses of food chains supporting isolated clusters of sporadic TSEs (CWD in N Colorado, scrapie in Iceland, CJD in Slovakia) demonstrate a consistent 2 1/2+ fold greater concentration of the pro-oxidant divalent cation, manganese (Mn), in relation to normal levels recorded in adjoining TSE-free localities. Deficiencies of the antioxidant co factors Cu/Se/Zn/Fe and Mg, P and Na were also consistently recorded in TSE foodchains. Similarities between the clinical/pathological profile of TSEs and Mn delayed psycho-neurotoxicity in miners are cited, and a novel theory generated which suggests that sporadic TSE results from early life dependence of TSE susceptible genotypes on ecosystems characterised by this specific pattern of mineral imbalance. Low Cu/Fe induces an excessive absorption of Mn in ruminants and an increased oxidation of Mn2+ into its pro oxidant species, Mn3+, which accumulates in mitochondria of CNS astrocytes in Mn SOD deficient genotypes. Deficiencies of scavenger co factors Cu/Zn/Se/Fe in the CNS permits Mn3+ initiated chain reactions of auto-oxidant mediated neuronal degeneration to proliferate, which, in turn, up-regulates the expression of the Cu-metalloprotein, prion protein (PrP). Once the rate of PrP turnover and its demand for Cu exceeds the already depleted supply of Cu within the CNS, PrP can no longer bind sufficient Cu to maintain its conformation. Mn3+ substitutes at the vacated Cu domain on PrP, thus priming up a latent capacity for lethal auto-oxidative activity to be carried along with PrP like a 'trojan horse'; where Mn 3+ serves as the integral 'infectious' transmissible component of the misfolded PrP-cation complex. The Mn overactivation of concanavalin A binding to glycoprotein and Mn-initiated autoxidation results in a diverse pathological profile involving receptor capping, aggregation/modification of CNS membrane/cytoskeletal proteins. TSE ensues. The BSE/nv CJD strain entails a 'synthetic' induction of the same CNS mineral disturbance, where 'in utero' exposure to Cu-chelating insecticides/Mn supplements accelerates the onset of a more virulent 'strain' of adolescent TSE.

High-dose exposure to systemic phosmet insecticide modifies the phosphatidylinositol anchor on the prion protein: the origins of new variant transmissible spongiform encephalopathies?

Compulsory exposure of the UK bovine to exclusively high biannual doses of a 'systemic' pour-on formulation of an organo-phthalimido-phosphorus warblecide, phosmet, during the 1980s (combined with exposure to the lipid-bound residues of 'bioconcentrated' phosmet recycled back via the intensive feeding of meat and bone meal), initiated the 'new strain' modification of the CNS prion protein (PrP) causing the UK's bovine spongiform encephalopathy (BSE) epidemic. A lipophilic solution of phosmet was poured along the bovine's spinal column, whence it penetrated and concentrated in phospholipids of the CNS membranes, covalently modifying endogenous phosphorylation sites on phosphatidylinositols (PIs) etc., forming a 'toxic membrane bank' of abnormally modified lipids that 'infect' any membrane proteins (such as PrP) that are programmed to conjugate onto them for anchorage to the membrane. Thus, phosmet invokes a primary covalent modification on PrP's PI anchor which, in turn, invokes an overall diverse disturbance upon CNS phosphoinositide second messenger feed back cycle, calcium homeostasis and essential free radicals; thus initiating a self-perpetuating cascade of abnormally phosphorylated PI-PrP that invokes a secondary electrostatic and allosteric disturbance on the main body of PrP impairing tertiary folding. Chaperone stress proteins conjugate onto misfolded PrP blocking its sites of proteolytic cleavage. Fresh epidemiological evidence is presented and experimental evidence referenced that adds support to a multifactorial hypothesis which proposes that BSE is a hitherto unrecognized and previously unmanifested class of subtle chronic phosmet-induced delayed neuro-excitotoxicity in the susceptible bovine.

The UK epidemic of BSE: slow virus or chronic pesticide-initiated modification of the prion protein? Part 1: Mechanisms for a chemically induced pathogenesis/transmissibility

It is proposed that exposure of the bovine embryo to specific high-dose lipophilic formulations of organophosphate insecticide (containing phthalimide) applied exclusively in the UK during the 1980s/early 1990s was the primary trigger that initiated the UK's bovine spongioform encephalopathy epidemic. Multi-site binding organophosphate toxic metabolites penetrate the fetus, covalently binding with, phosphorylating and ageing serine, tyrosine or histidine active sites on fetal central nervous system prion protein. An abnormal negative charge corrupts prion protein molecular surface, which blocks both proteases and chaperones from accessing their cleavage/bonding sites. This impairs normal degradation and folding of prion protein respectively. Once the abnormally phosphorylated abnormal prion protein isoform agent is initiated, any stress event ensuing in adult life induces a nerve growth factor-mediated synthesis of normal cellular prion protein isoform that aggregates to abnormally phosphorylated abnormal prion protein isoform, thereby becoming 'infected'/transformed into the same; due to the vicious circle of positive feedback invoked by the blocking of a prion protein-specific kinase. Prion protein could therefore serve as a hitherto unrecognized critical link in a chain of delayed neuroexcitotoxic proteins that are triggered off by chronic exposure to specific classes of chemical/metal that 'hit and run' during the vulnerable in utero period, producing spongioform encephalopathy disease years later.

The UK epidemic of BSE: slow virus or chronic pesticide-initiated modification of the prion protein? Part 2: An epidemiological perspective

This paper elucidates the flaws in the official hypothesis that bovine spongioform encephalopathy originated from alterations in the way that scrapie-contaminated cattlefeeds were manufactured in the UK. An alternative hypothesis is proposed that cites exposure of the bovine embryo to various specific high-dose lipophilic formulations of organophosphates, such as the high-dose phthalimide containing organophosphate phosmet, (which were applied compulsorily and exclusively in the UK during the 1980s/early 1990s) as the primary trigger that initiated the deformation of prion protein and the onset of the bovine spongioform encephalopathy epidemic. The multi-site binding metabolites of these organophosphates penetrate the fetus, covalently phosphorylating various active sites on fetal prion protein. The extra charged phosphate groups left on aged prion protein blocks both proteases and chaperones from accessing their catalytic/bonding sites, creating the undergradable, misfolded isoform of prion protein, PrPsc. The resulting abnormally phosphorylated PrPsc aggregates to freshly synthesized PrPc, transforming it into same; due to a system of positive feedback invoked by the organophosphate-induced blockage of a prion protein-specific protein kinase. Both the timing, distribution and dynamics of usage of these specific organophosphates correlates with the epidemiology of bovine spongioform encephalopathy as well as accounting for the 23,000 cattle that have developed the disease, yet were born after the 1988 ban on scrapie-contaminated cattlefeed.