Future of 5-fluorouracil in cancer therapeutics, current pharmacokinetics issues and a way forward

Background: In addition to exhibiting antitumor potential, antitumor drugs exhibit toxicity due to a poor pharmacokinetic profile. An enormous amount of research has been carried out and is still ongoing to obtain more targeted, potent, and safe drugs to treat cancer, and pharmacokinetic evaluations of anticancer drugs are needed. Objectives: The present review examined different delivery systems and methodologies designed in recent years to investigate the pharmacokinetics of the anticancer drug, 5-fluorouracil (5-FU). These methodologies highlight how the issues of bioavailability, absorption, half-life, targeted neoplastic cell potential, and high therapeutic index of 5-FU are resolved. Results: A number of naturally occurring macromolecules such as modified starch, porphyran, peptides, and folic acids have been found to be successful in vitro to improve the permeability and retention effect of 5-FU against solid tumors. A promising approach for targeted 5-FU delivery to oncoproteins has resulted in a number of potentially sound anticancer nanocomposites. Chitosan nanoparticles loaded with 5-FU have been shown to exhibit cytotoxicity equivalent to 5-FU injections against gastric carcinoma. At the level of inter- and intra-molecular interactions, the co-crystal approach has been found to be successful against colorectal cancer proteins. Because of the 5-FU ligand-like nature and its metal-binding potential, researchers have shifted attention toward the synergistic co-administration of gold complexes with this drug. Conclusions: This study highlighted the techniques used to improve the pharmacokinetics of 5-FU and that “nanocarriers” are a promising approach in this field. The conclusion is supported by solid evidence

The social mobility challenges faced by young muslims

Young Muslims face the 'broken promise of social mobility': compared to other groups, their improved success in education at all levels does not translate into good labour market outcomes. Despite their educational gains, Muslims experience the greatest economic disadvantages of any group in UK society. They are more likely than non-Muslims to experience neighbourhood deprivation, housing, educational and health disadvantage, and unemployment. This qualitative report explores the attitudes and reasons behind this situation. It offers an account of young Muslims’ perceptions of growing up and seeking work in the UK. The report is designed to contribute to a better understanding of the causes of low social mobility for young Muslims. Drawing on the perceptions of young Muslims (through focus groups and interviews) and of key stakeholders (through a three-stage Delphi survey) the research sought evidence on: • The barriers young Muslims see to social mobility in the UK – in particular, why educational gains are not translating into employment gains for young Muslims. • How these perceptions differ depending on gender, ethnicity, socio-economic background and different forms of educational participation

NANU BARI: For People Who Love Desi Food – and Their Grandma: A Food Truck Business Plan

This thesis details the steps necessary to successfully start a mobile restaurant operation (food truck) in the greater Boston area. A primary issue to consider before starting this business venture is the permitting process and what permits are necessary to operate a food truck. As such, a business plan will be required in order to be able to obtain the permits. Along with the business plan, a detailed marketing section illustrating the brand for the business is needed. The marketing plan will include a mission statement or a “why” page to include in our marketing. The vision for this section is to craft a statement that customers can associate our business with; telling the story of my family’s culture, why we pursued the business and emphasizing the importance of food and family. Another primary consideration is where to buy a food truck, how much capital is required, and determining costs of all the necessary renovations. There are many potentially overwhelming steps to starting a food truck, but this thesis will break those steps down into manageable sections to create a comprehensive plan to follow in order to successfully open a competitive and appealing food truck business in the Greater Boston Area.Business Administratio

Changes in skeletal integrity and marrow adiposity during high-fat diet and after weight loss

The prevalence of obesity has continued to rise over the past three decades leading to significant increases in obesity-related medical care costs from metabolic and non-metabolic sequelae. It is now clear that expansion of body fat leads to an increase in inflammation with systemic effects on metabolism. In mouse models of diet-induced obesity there is also an expansion of bone marrow adipocytes. However, the persistence of these changes after weight-loss has not been well described. The objective of this study was to investigate the impact of high-fat diet (HFD) and subsequent weight-loss on skeletal parameters in C57Bl6/J mice. Male mice were given a normal chow diet (ND) or 60% HFD at 6-weeks of age for 12-, 16-, or 20-weeks. A third group of mice was put on HFD for 12-weeks and then on ND for 8-weeks to mimic weight-loss. After these dietary challenges the tibia and femur were removed and analyzed by microCT for bone morphology. Decalcification followed by osmium staining was used to assess bone marrow adiposity and mechanical testing was performed to assess bone strength. After 12-, 16-, or 20-weeks of HFD, mice had significant weight gain relative to controls. Body mass returned to normal after weight-loss. Marrow adipose tissue (MAT) volume in the tibia increased after 16-weeks of HFD and persisted in the 20-week HFD group. Weight loss prevented HFD-induced MAT expansion. Trabecular bone volume fraction, mineral content, and number were decreased after 12-, 16-, or 20-weeks of HFD, relative to ND controls, with only partial recovery after weight-loss. Mechanical testing demonstrated decreased fracture resistance after 20-weeks of HFD. Loss of mechanical integrity did not recover after weight-loss. Our study demonstrates that HFD causes long-term, persistent changes in bone quality, despite prevention of marrow adipose tissue accumulation, as demonstrated through changes in bone morphology and mechanical strength in a mouse model of diet-induced obesity and weight-loss

Catalytic Upgrading of Biomass Fermentation Products and Bio-methane to Energy Dense Hydrocarbon Fuels

Since the last few decades of 20th century, studies on renewable and alternative energy sources have drawn much attention both in academic and industrial research. The public and private sectors felt the obvious need of discovering alternative energy sources other than petroleum crude due to its limited supply compared to the increasing demand with fast pace of modern civilization and industrialization worldwide. New policies and acts are being enabled to encourage the research and application of renewable and alternative energy and fuels. In transportation sector, to use the alternative and renewable energy sources without massive change of the established infrastructure, only biomass and bio-resources can be chemically converted or upgraded to liquid transportation fuel which can be used as drop-in fuel or fuel blend in conventional automobile engines. Biomass conversion to liquid oil can be done in several ways like biochemical conversion i.e. fermentation, thermo-chemical conversion i.e. pyrolysis etc. In this study biomass fermentation products such as alcohol ketone and carboxylic acid mixtures and also bio-methane or shale gas are catalytically upgraded in a thermochemical conversion process to produce energy dense higher hydrocarbon molecules that can be used as liquid fuel or energy sources. Acetone-butanol-ethanol (ABE) mixture, containing 62.9 wt% n-butanol, 29.3 wt.% acetone and 7.8 wt.% ethanol, can be produced from biomass through the well-established ABE fermentation process using genetically-modified Clostridium acetobutylicum. In Chapter 2, the catalytic dehydration reactions of ABE mixture are studied to deoxygenate the mixture. Feed of ABE mixture was preheated and pumped through a catalytic packed bed tubular reactor in a continuous process at pressures of 3-6 bars. Experiments were run at different operating temperatures and feed flow rates to investigate the effect on the dehydration products, which are mixtures of three phases: (1) a gas phase consisting of light hydrocarbons and carbon dioxide, (2) an organic liquid phase consisting of heavy hydrocarbons, and (3) an aqueous phase with dissolved oxygenated hydrocarbons. The conversion was examined on two different catalysts: an alumina (γ-Al2O3) and a zeolite (ZSM-5). The dehydration products from the ABE mixture were mostly unsaturated hydrocarbon chains in the range of C2-C16. Based on the higher heating values (HHV) of the liquid products and infra-red spectra of the gas products, it can be concluded that the products from the ABE feedstock were different than those from the individual components, which suggests a cross reactivity of the components during the reaction. HHV of the liquid product increased with a decrease in the feed flow rate, and γ-Al2O3 catalyst was found to perform better than ZSM-5 for getting a good conversion of ABE in terms of liquid product energy content at a moderate reaction time. The gaseous product contained mostly 1-butene and its isomers and some other lighter unsaturated hydrocarbon gases. This gas stream was used as the extractant in Chapter 3 to study the separation of ABE components from dilute aqueous solution having the same concentration of the fermentation broth. Chemically pure 1-butene gas was liquefied in a pressure vessel where direct liquid-liquid extraction takes place and mole based distribution coefficient of 1.71 was attained for n-butanol single component extraction. For acetone, ethanol and butyric acid extraction separately from aqueous solvent the distribution coefficients were lower. To compare the separation efficiency a two-step approach of adsorption on activated charcoal followed by liquid-solid extraction using 1-butene and percent recovery of each of the components, mole and mass based distribution coefficients were calculated and it was observed that other than for n-butanol, the distribution coefficients for other components increased compared to that of the direct liquid-liquid extraction process. For extraction of ABE as a mixture, a preferential extraction of n-butanol was observed over the other components in the mixture due to its least polar characteristic among the components and thus higher solubility in the organic phase. Another significant and common product in biomass fermentation processes using Clostridium genus biocatalysts is butyrates or butyric acid. For example, it is produced as a by-product with acetone-n-butanol-ethanol (ABE) mixture in the well-known ABE fermentation process. Using genetically modified microbial strain in an advanced fermentation method with integrated separation, a butyric acid concentration of as high as 60 g/l can be achieved. Butyric acid can be further catalytically deoxygenated to produce ketones and long-chain hydrocarbons. In Chapter 4 of this study, conversional efficiencies of two commercial acid catalysts γ-Al2O3 and ZrO2 are examined. For in-situ aromatization of the deoxygenation products in a single step reactor, ZSM-5 catalyst was tested in a series bed followed by γ-Al2O3 and ZrO2. Due to the amphoteric properties of having both lewis acid and basic sites and also stronger aprotonic acid sites due to higher concentration of oxygen in the molecule, ZrO2 has much superior deoxygenation activity than γ-Al2O3, as former showed above 90% conversion of butyric acid to high-energy organic liquids; for example, the higher heating value (HHV) of the organic liquid product is 36 kJ/g for the deoxygenation at 400°C. The composition of the liquid product depends upon the temperature and weight-hourly-space-velocity (WHSV), and the heavy hydrocarbons can be produced in a single step though the yield decreases with increase in temperature. Almost equal amounts of n-heptanone and aromatic components are produced when a series packed bed of ZrO2 and ZSM-5 is used. An optimum condition for a series bed of ZrO2 and ZSM-5 catalysts has been determined to produce a mixture of energy-dense hydrocarbons and aromatics directly from butyric acid. In Chapter 5 of this study catalytic upgrading of methane from bio resources as well as from shale gas is discussed in a direct and more energy efficient route without using oxygen. In this work, a noble transition metal, ruthenium, is chosen as the catalyst with the objective of lowering the methane activation temperature, higher stability and also to have better conversion than other transition metal catalysts which are studied. The catalyst was prepared by 1.5 wt. % or 3 wt.% ruthenium loading on ZSM-5, zeolite support and on silica support separately to compare the effect of metal loading and metal support combination on the conversion process. The operating temperature was varied from 400° to 800°C. From online GC analysis and FT-IR analysis of the product gas it was observed that a sudden rise in methane conversion took place at 700°C operating temperature on 3 wt.% Ru/ZSM-5 catalyst bed and heavy hydrocarbon molecules of C4 to C10 range was produced but with a very low yield. For 1.5 wt.% Ru/ZSM-5 and 3 wt.% Ru/SiO2 catalyst beds , methane conversion were found to be low even at high temperature and no significant production of higher hydrocarbon molecules were observed. A catalyst bed of 3 wt.% Ru/SiO2 followed by pure ZSM-5 in series is also studied and the products are found to be comparable with that of 3 wt.% Ru/ZSM-5 catalyst bed with high methane conversion. The special framework structure in the ZSM-5 catalyst influenced the product molecular structure to produce cyclic higher hydrocarbon molecules after methane is activated on the surface with ruthenium metal catalyst and produced methyl radicals at above 700°C in a considerable amount. In this work as the catalysts are prepared in the lab, extensive catalyst characterization is done for both fresh and spent catalysts to determine the changes and stability. The probable future directions of continuation and improvement of the catalytic upgrading processes are discussed in a brief manner in Chapter 6 of this study

Molecular Mechanisms Regulating Ontogeny of O2- and CO2-Chemosensitivity in Rat Adrenomedullary Chromaffin Cells: Role of Nicotinic ACh and Opioid Receptor Signalling

Catecholamine (CAT) secretion from adrenomedullary chromaffin cells (AMCs) is essential for survival of the fetus and for adaptation of the newborn to extrauterine life. CAT secretion protects the fetus from intrauterine hypoxia (low O2) and is required for maintaining cardiac conduction and preparing the lungs for air breathing. Asphyxial stressors (e.g. hypoxia, hypercapnia (high PCO2), and acidosis (low pH)) arising from labor contractions and postnatal apneas, are the main stimuli for the ‘non-neurogenic’ CAT release from perinatal AMCs. In the rat, the mechanisms of hypoxia chemosensitivity in AMCs involve inhibition of a variety of K+ channels, leading to membrane depolarization, voltage-gated Ca2+ entry, and CAT secretion. The magnitude of this depolarization is regulated by the simultaneous activation of ATP-sensitive K+ (KATP) channels, which tends to hyperpolarize the membrane potential during hypoxia. Interestingly, chemosensitivity of rat AMCs and CAT secretion in response to asphyxial stressors are markedly reduced postnatally following the development of functional innervation of these cells by the splanchnic nerve. The primary purpose of this thesis was to delineate molecular mechanisms involved in the suppression of hypoxia and hypercapnia chemosensitivity following splanchnic innervation in neonatal rat AMCs. Experiments were designed to test the general hypothesis that the ontogeny of O2 and CO2 sensitivity in AMCs is regulated by the activation of postsynaptic nicotinic ACh and opioid receptor signalling pathways following innervation. Previous studies in this laboratory showed that exposure of perinatal rat AMCs to nicotine in utero and in vitro resulted in the selective blunting of hypoxia (but not hypercapnia) chemosensitivity. The underlying mechanism was attributable to the increased membrane hyperpolarization caused by the functional upregulation of KATP channels. In Chapter 2, I report the results of investigations of molecular mechanisms involved in the nicotine-induced upregulation of KATP channels, using a rat fetal-derived, O2- and CO2-sensitive immortalized chromaffin cell line (MAH cells), as a model. Exposure of MAH cells to chronic nicotine (50 μM) for 7 days in culture caused an increase in the expression of the KATP channel subunit, Kir6.2. This effect was blocked by α-bungarotoxin, a blocker of homomeric α7 nicotinic acetylcholine receptors (α7 nAChRs). The upregulation of Kir6.2 in MAH cells was also dependent on the transcription factor, hypoxia inducible factor (HIF)-2α. First, whereas the upregulation of Kir6.2 was present in wild type and scrambled control MAH cells, it was absent in HIF-2α-deficient (shHIF-2α) MAH cells. Second, chronic nicotine caused a progressive, time-dependent increase in HIF-2α accumulation that occurred in parallel with the increase in Kir6.2 expression. Third, chromatin immunoprecipitation (ChIP) assays revealed the binding of HIF-2α to a hypoxia response element (HRE) in the promoter region of the Kir6.2 gene. These data suggest that chronic nicotine causes the accumulation of HIF-2α which results in the transcriptional upregulation of the Kir6.2 gene. These observations were validated in an in vivo model where rat pups were exposed to nicotine in utero. Western blot analysis of adrenal gland tissues from nicotine-exposed (relative to saline-exposed) pups revealed a significant increase in Kir6.2 subunit expression and HIF-2α accumulation, and both were restricted to the medullary (but not cortical) tissue. Chapter 3 tested the hypothesis that postnatal innervation causes the suppression of O2- and CO2-chemosensitivity in neonatal AMCs via opioid receptor signalling. It was found that chronic μ- and δ-opioid agonists (2 μM) in vitro led to the suppression of both O2- and CO2-chemosensitivity; this was correlated with the upregulation of KATP channel expression and the downregulation of carbonic anhydrase (CA) I and II respectively. The underlying molecular and signalling mechanisms were further investigated in Chapter 4. Using the MAH cell model, it was found that exposure to a combination of μ- and δ-opioid agonists for 7 days resulted in the naloxone-sensitive upregulation of Kir6.2 subunit and the downregulation of CAII. Similar to chronic nicotine exposure, the effects of chronic opioids on the upregulation of Kir6.2 and downregulation of CAII were HIF-2α-dependent. Western blot analysis revealed that HIF-2α accumulation in opioid-treated MAH cells occurred along a time-course that paralleled the upregulation of Kir6.2 subunit. ChIP assays demonstrated the binding of HIF-2α to the promoter region of the Kir6.2 subunit gene in opioid-treated MAH cells. Moreover, PKA activity (but not PKC or CaMK) was found to be required for the effects of opioids on Kir6.2 and CAII expression, but not HIF-2α accumulation. In complementary in vivo studies, adrenomedullary tissues from morphine-exposed rat pups showed an increased expression of both HIF-2α and Kir6.2, and decreased expression of CA1 and II protein. These findings have uncovered novel mechanisms by which postnatal innervation contributes to the ontogeny of O2- and CO2-chemosensitivity in rat adrenal chromaffin cells. They also suggest mechanisms by which exposure of the fetus to nicotine in cigarette smoke or opioids from drug abuse might contribute to abnormal arousal reflexes, and pathophysiological conditions such as Sudden Infant Death Syndrome (SIDS).Doctor of Philosophy (PhD