2,4-Dienoyl-coenzyme A reductase deficiency: a possible new disorder of fatty acid oxidation.

Several inherited disorders of fatty acid beta-oxidation have been described that relate mainly to saturated precursors. This study is the first report of an enzyme defect related only to unsaturated fatty acid oxidation and provides the first in vivo evidence that fat oxidation in humans proceeds by the reductase-dependent pathway. The patient was a black female, presenting in the neonatal period with persistent hypotonia. Biochemical studies revealed hyperlysinemia, hypocarnitinemia, normal organic acid profile, and an unusual acylcarnitine species in both urine and blood. The new metabolite was positively identified by mass spectrometry as 2-trans,4-cis-decadienoylcarnitine, derived from incomplete oxidation of linoleic acid. In spite of dietary therapy, the patient died of respiratory acidosis at four months of age. Samples of liver and muscle from the autopsy were assayed for 2,4-dienoyl-coenzyme A reductase activity. Using the substrate 2-trans,4-cis-decadienoylcoenzyme A, the reductase activity was 40% of the control value in liver and only 17% of that found in normal muscle. It is suggested that unsaturated substrates should be used for in vitro testing to cover the full range of potential beta-oxidation defects and that acylcarnitine species identification be used for in vivo detection of this disorder.     

Resistance of human astrocytoma cells to apoptosis induced by mitochondria-damaging agents: possible implications for anticancer therapy

The success of anticancer chemotherapy is often hampered by resistance to apoptosis, which may depend on defects in intracellular cell death pathways. Characterizing the alterations of these pathways is a prerequisite for developing alternative and effective antitumoral strategies. Here, we investigated the susceptibility of a human astrocytoma cell line, ADF, to apoptotic cell death induced by mitochondria-damaging agents. Neither the anticancer agent betulinic acid nor the "mitochondriotropic" poisons 2-deoxy-d-ribose and potassium cyanide induced apoptosis of these cells, despite induction of highly significant mitochondrial depolarization, eventually resulting in necrotic death. Resistance to apoptosis was not due to presence of the multidrug resistance pump or to impaired expression of caspase-8, caspase-9, or "executioner" caspase-3. Cloning of caspase-9 revealed the presence of full-length caspase-9alpha and a short variant (caspase-9beta), which, in other tumors, acts as a dominant negative of the long isoform. All analyzed clones showed a point mutation in the prodomain region that is known to interact with mitochondria-released factors. Thus, in these human astrocytoma cells, mitochondria-damaging agents induce a regulated form of mitochondrial-dependent necrotic cell death (oncosis). Resistance to apoptosis is due to an intrinsic defect of caspase-9, leading to inhibition of enzyme activation and/or impaired interaction with proteins released from depolarized mitochondria. These results may have implications for developing strategies aimed at overcoming tumor resistance to chemotherapy.     

Indian medicinal mushrooms as a source of antioxidant and antitumor agents

Medicinal mushrooms occurring in South India namely Ganoderma lucidum, Phellinus rimosus, Pleurotus florida and Pleurotus pulmonaris possessed profound antioxidant and antitumor activities. This indicated that these mushrooms would be valuable sources of antioxidant and antitumor compounds. Investigations also revealed that they had significant antimutagenic and anticarcinogenic activities. Thus, Indian medicinal mushrooms are potential sources of antioxidant and anticancer compounds. However, intensive and extensive investigations are needed to exploit their valuable therapeutic use.     

The role of a peripheral dopamine-antagonist (Motilium) in improving the tolerance to steroidal and non-steroidal anti-inflammatory agents

Domperidone protective therapy has been applied in 50 patients suffering from locomotor disease, who responded with dyspeptic complaints to the steroidal and non-steroidal antiphlogistic therapies which meant a risk of the activation of an earlier gastro-intestinal disease. The basic therapy could be applied to 80% of patients due to the Motilium protection because of the favourable changes in gastro-intestinal symptoms. Since domperidone is well tolerated by the patients and it does not yield higher risks, it's use is highly recommended as a protective therapy as well.     

Measurement of plasma 5-hydroxyindoleacetic acid as a possible clinical surrogate marker for the action of antivascular agents.

BACKGROUND: Serotonin (5HT), a naturally occurring vasoactive substance, is released from platelets into plasma under various pathological conditions. Recently, anticancer drugs that act by selectively disrupting tumour blood flow have been found to increase plasma 5HT concentrations in mice. Two such antivascular agents, flavone acetic acid (FAA) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA), have completed Phase I clinical trial and raise the important question of whether suitable surrogate markers for antivascular effects can be identified. METHODS: 5HT is unstable to storage, precluding routine clinical assay, but the 5HT metabolite, 5-hydroxyindoleacetic acid (5HIAA) accumulates in plasma following 5HT release and is a more suitable marker because of its greater stability. We have developed an automated procedure for the assay of the low concentrations of 5HIAA found in humans by combining solid-phase extraction with high-performance liquid chromatography (HPLC). RESULTS: Efficient separation of 5HIAA from possible interfering substances in human plasma, including a variety of pharmaceutical agents, was achieved on C18 columns using cetyltrimethylammonium bromide (CETAB) as an organic modifier. Adequate precision, accuracy and sensitivity were achieved by electrochemical detection (ECD) at +400 mV. Analysis of plasma from two patients treated with DMXAA in a Phase I trial demonstrated DMXAA-induced elevation of plasma 5HIAA with a time course similar to that previously described in mice. CONCLUSIONS: Measurement of changes in plasma 5HIAA provides a new approach to the monitoring of therapies with an antivascular effect. The assay is sensitive to dietary sources of 5HT, which should be minimised.     

Maleimide index: a paleo-redox index based on fragmented fossil-chlorophylls obtained by chromic acid oxidation

The composition of past photosynthetic organisms provides information about the paleo-environment based on the habitat characteristics of photosynthetic organisms. Therefore, analysis of chlorophyll-derived materials from photosynthetic organisms in sedimentary rocks is important for understanding paleo-environmental changes. Fossilized chlorophylls present in sedimentary rocks can be detected by their conversion into maleimides and phthalimides. This can be achieved through the chromic acid oxidation of sedimentary rocks. Since the maleimides and phthalimides are derived from the pyrrole skeleton of fossil chlorophylls, their composition reflects the composition of paleo-photosynthetic organisms. We herein propose an indicator for detecting anoxic-sulfidic conditions in the paleo oceanic photic zone, which is based on the composition ratio of the maleimides produced during the oxidation process. The maleimide index in this study would be a useful analytical method to indicate that anoxic-sulfidic conditions in the paleo oceanic photic zone, which is associated with mass extinction events, have occurred.

In this study, a paleo-redox index using chlorophyll-derived substances incorporated into insoluble polymers in sedimentary rocks was proposed.     

Enhancement of the antitumor effects of 5-fluorouracil by folinic acid

Although 5-fluorouracil (FUra) is one of the most effective cytotoxic agents in the treatment of various solid tumors (carcinomas of the gastro-intestinal tract, breast, head and neck), remissions occur in only 20-30% of cases and usually are of short duration. Recently, preclinical studies have shown that the antitumor activity of FUra can be potentiated by modulating the metabolism of this drug by using other substances, in particular 5-formyltetrahydrofolate (folinate, LV). Reduced folates (LV and 5-methyltetrahydrofolate) at concentrations greater than or equal to 1 microM can, by raising the intracellular levels of 5,10-methylenetetrahydrofolate, increase and prolong the inhibition of the target enzyme, thymidylate synthase, with formation of a stable ternary complex formed by the enzyme, the folate coenzyme and the fluoropyrimidine inhibitor (5-fluorodeoxyuridylate). After phase II clinical trials reported encouraging results with the combination LV-FUra in the treatment of patients with various solid tumors, randomized controlled studies in patients with colorectal carcinoma have documented an increase in the response rate of the combination compared to treatment with FUra alone. The integration of the LV-FUra combination into multidrug regimens is now under investigation for the treatment of carcinomas of the breast, stomach, and head and neck.     

A method of comparing the toxicities of disease suppressive agents: possible application to a comparison between D-penicillamine and chloroquine

A general method for calculating incidences of the more common adverse reactions during long-term therapy with disease suppressive agents is presented. With D-penicillamine treatment, the incidence of proteinuria rises during 6-12 months and then declines, but with aurothiomalate treatment the incidence of proteinuria and rash progressively decline. Low-dose chloroquine treatment was associated with a much lower withdrawal rate due to adverse reactions compared to D-penicillamine. However, the efficacy at mean doses of chloroquine less than 250 mg day-1 has not been formally evaluated. A formal, well-controlled trial comparing D-penicillamine, at current dosage, and of chloroquine, at low dosage, seems warranted in order to place the usefulness of D-penicillamine in perspective.     

A possible role for malonyl-CoA in the regulation of hepatic fatty acid oxidation and ketogenesis.

Studied on the oxidation of oleic and octanoic acids to ketone bodies were carried out in homogenates and in mitochondrial fractions of livers taken from fed and fasted rats. Malonyl-CoA inhibited ketogenesis from the former but not from the latter substrate. The site of inhibition appeared to be the carnitine acyltransferase I reaction. The effect was specific and easily reversible. Inhibitory concentrations were in the range of values obtained in livers from fed rats by others. It is proposed that malonyl-CoA functions as both precursor for fatty acid synthesis and suppressor of fatty acid oxidation. As such, it might be an important element in the carbohydrate-induced sparing of fatty acid oxidation.     

Iron chelation as a possible mechanism for aspirin-induced malondialdehyde production by mouse liver microsomes and mitochondria.

To investigate the possibility that lipid peroxidation is the mechanism responsible for aspirin-induced liver damage, pure neutralized acetylsalicylic acid (ASA), 0.6-90.9 mM, was added to calcium-aggregated mouse liver microsomes followed by incubation in NADPH buffer at 37 degrees C for 60 min and subsequent measurement of malondialdehyde (MDA). MDA production at ASA concentrations from 1.2 to 4.6 mM was greater than control (P less than 0.004). Peak MDA values were observed with 4.6 mM ASA, 39.58 +/- 6.73 nmol MDA/mg protein vs. 16.16 +/- 2.85 (P less than 0.004). Higher concentrations of ASA were inhibitory compared with the value at 4.6 mM (P less than 0.001). Aspirin had similar effects on MDA production by mouse liver mitochondria. MDA production with either ASA or buffer was completely suppressed by the potent iron-chelating agents desferrioxamine and alpha,alpha' dipyridyl when these were added to the microsomal preparations. Since MDA production in this system is known to be affected by iron-chelating agents (enhanced at low concentration, inhibited at higher concentration), the iron-chelating properties of ASA were investigated. Conductivity titration curves of Fe(OH)3 added to water or ASA suggested that the ASA was complexing with iron. The presence of an iron-ASA complex was established by high pressure liquid chromatographic analysis of the solution from this study. We conclude that aspirin enhances MDA production by hepatic microsomes and mitochondria via an aspirin-iron chelate and that this represents at least one mechanism by which aspirin may produce liver damage.     

Lipoic acid capped silver nanoparticles: a facile route to covalent protein capping and oxidative stability within biological systems

Covalent attachment of human serum albumin protein to the surface of spherical lipoic acid capped silver nanoparticles results in the generation of stable nanoparticle–protein hybrids with well defined surface composition. Enhanced stability towards oxidation and in the presence of complex media with high ionic strength, holds promise towards the use of these conjugates as therapeutics in biomedical applications and sensing.

Covalent attachment of human serum albumin protein to the surface of spherical lipoic acid capped silver nanoparticles results in the generation of stable nanoparticle–protein hybrids with well defined surface composition.     

Training to be a Veterinary Nurse: the degree route

Have you heard of the degree VN course and wondered what it involves, or worked alongside an undergraduate veterinary nurse in practice? The aim of this article is to provide an insight into the degree route to the RVN qualification, based upon my experience as a degree student.     

ortho-Naphthoquinone-catalyzed aerobic oxidation of amines to fused pyrimidin-4(3H)-ones: a convergent synthetic route to bouchardatine and sildenafil

A facile access to fused pyrimidin-4(3H)-one derivatives has been established by using the metal-free ortho-naphthoquinone-catalyzed aerobic cross-coupling reactions of amines. The utilization of two readily available amines allowed a direct coupling strategy to quinazolinone natural product, bouchardatine, as well as sildenafil (Viagra™) in a highly convergent manner.

Fused pyrimidin-4(3H)-one derivatives have been accessed by using the ortho-naphthoquinone-catalyzed aerobic cross-coupling reactions of amines.

N-Heterocyclic compounds with a pyrimidin-4(3H)-one core constitute a large number of natural products and biologically active molecules. For example, quinazolinone alkaloids possess a phenyl-fused pyrimidin-4(3H)-one structure and display a wide spectrum of pharmacological activities (Scheme 1a).¹ Sildenafil (Viagra™), a potent and selective inhibitor of type 5 phosphodiesterases on smooth muscle cell, is based on the pyrazole-fused pyrimidin-4(3H)-one structure and marketed for erectile dysfunction.² The synthetic approaches to the phenyl-fused pyrimidin-4(3H)-ones, quinazolinones, typically involve the condensation between anthranilamides and aldehydes to give aminal intermediates that in turn oxidized to quinazolinones under oxidation conditions (Scheme 1b). The oxidation catalysts include Cu,³ Fe,⁴ Ga,⁵ Ir,⁶ Mn,⁷ iodine,⁸ peroxide,⁹ however the aerobic oxidation of aminal intermediates is also known at 150 °C.¹⁰ The utilization of alcohols also effects the one-pot synthesis of quinazolinones through in situ oxidation to aldehydes in the presence of Fe,¹¹ Ir,¹² Mn,¹³ Ni,¹⁴ Pd,¹⁵ Ru,¹⁶ V,¹⁷ Zn,¹⁸ and iodine catalysts.¹⁹ Other precursors to aldehydes have been also identified using alkynes,²⁰ benzoic acids,²¹ indoles,²² α-keto acid salts,²³ β-keto esters,²⁴ styrenes,²⁵ sulfoxides,²⁶ and toluenes.²⁷ Non-aldehyde approaches to quinazolinones have been also demonstrated in the cross coupling of amidines,²⁸ amines,²⁹ benzamides,³⁰ isocyanides,³¹ and nitriles.³² In 2013, the Nguyen group disclosed the synthesis of four quinazolinones, utilizing the autooxidation of benzylamines to imines that subsequently condensed with anthranilamides.³³ While a closed system at 150 °C was necessary, the use of 40 mol% AcOH without solvent provided the quinazolinones in 46–75% yields. The Nguyen group also developed the FeCl₃·6H₂O-catalyzed condensation of 2-nitroanilines and benzylamines in the presence of 20 mol% of S₈, where six quinazolinones were obtained in 68–75% yields.³⁴ While the cross condensation of anthranilamides and benzylamines was accomplished, there exists a significant knowledge gap due to the limited substrate scope combined with less optimal reaction conditions (i.e. high reaction temperature, closed system in neat conditions and excess use of amines). In addition, it is not entirely clear if the cross condensation of amide-containing amines and benzylamines would work for other fused pyrimidin-4(3H)-one derivatives.³⁵ To address such shortcomings in the cross condensation of amines, the ortho-naphthoquinone (o-NQ)-catalyzed aerobic cross amination strategy was investigated (Scheme 1c).³⁶ Herein, we report a highly general approach to fused pyrimidin-4(3H)-one derivatives in the presence of o-NQ catalyst, culminating to the direct aerobic coupling of two amines to bouchardatine and sildenafil.Open in a separate windowScheme 1Biologically active fused pyrimidin-4(3H)-one derivatives and their synthetic methods.Given that the o-NQ-catalyzed aerobic cross coupling of benzylamines and aniline derivatives such as o-phenylenediamines provided a facile approach to heterocyclic compounds including benzoimidazoles,³⁷ the use of anthranilamide 1a and benzylamine 2a was examined as a model study (38 The reaction in DMSO lowered down the ratio of 1a and 2a from 1.0 : 1.5 to 1.0 : 1.2 (entry 12) and the catalyst loading to 5 mol% without affecting the overall reaction efficiency (entry 13). The control experiments confirmed the critical roles of both o-NQ1 and TFA (entries 15–18), and the reaction utilized molecular oxygen as a terminal oxidant (entries 19 and 20). Piecing together the experimental data, the employment of 5 mol% o-NQ1 and 20 mol% TFA in DMSO at 100 °C was selected for further studies.Optimization of o-NQ-catalyzed aerobic cross-coupling of amines to quinazolinone^a

Chemoinducible gene therapy: a strategy to enhance doxorubicin antitumor activity

A replication-defective adenoviral vector, Ad.Egr-TNF.11D, was engineered by ligating the CArG (CC(A/T)6GG) elements of the Egr-1 gene promoter upstream to a cDNA encoding human tumor necrosis factor-alpha. We report here that Ad.Egr-TNF.11D is activated by the clinically important anticancer agents cisplatin, cyclophosphamide, doxorubicin, 5-fluorouracil, gemcitabine, and paclitaxel. N-acetylcysteine, a free radical scavenger, blocked induction of tumor necrosis factor-alpha by anticancer agents, supporting a role for reactive oxygen intermediates in activation of the CArG sequences. Importantly, resistance of PC-3 human prostate carcinoma and PROb rat colon carcinoma tumors to doxorubicin in vivo was reversed by combining doxorubicin with Ad.Egr-TNF and resulted in significant antitumor effects. Treatment with Ad.Egr-TNF.11D has been associated with inhibition of tumor angiogenesis. In this context, a significant decrease in tumor microvessel density was observed following combined treatment with doxorubicin and Ad.Egr-TNF.11D as compared with either agent alone. These data show that Ad.Egr-TNF.11D is activated by diverse anticancer drugs.     

Systemic correction of a fatty acid oxidation defect by intramuscular injection of a recombinant adeno-associated virus vector

Mitochondrial beta-oxidation of fatty acids is required to meet physiologic energy requirements during illness and periods of fasting or physiologic stress, and is most active in liver and striated muscle. Acyl-CoA dehydrogenases of varying chain-length specificities represent the first step in the mitochondria for each round of beta-oxidation, each of which removes two-carbon units as acetyl-CoA for entry into the tricarboxylic acid cycle. We have used recombinant adeno-associated virus (rAAV) vectors expressing short-chain acyl-CoA dehydrogenase (SCAD) to correct the accumulation of fatty acyl-CoA intermediates in deficient cell lines. The rAAV-SCAD vector was then packaged into either rAAV serotype 1 or 2 capsids and injected intramuscularly into SCAD-deficient mice. A systemic effect was observed as judged by restoration of circulating butyryl- carnitine levels to normal. Total lipid content at the injection site was also decreased as demonstrated by noninvasive magnetic resonance spectroscopy (MRS). SCAD enzyme activity in the injected muscle was found at necropsy to be above the normal control mouse level. This study is the first to demonstrate the systemic correction of a fatty acid oxidation disorder with rAAV and the utility of MRS as a noninvasive method to monitor SCAD correction after in vivo gene therapy.     

Reversible parkinsonism and cognitive decline due to a possible interaction of valproic acid and quetiapine

What is known and Objective: Combination therapy with valproic acid plus quetiapine is recommended as one of the first‐line approaches to treatment of manic or mixed episodes in patients with bipolar disorder. Case summary: A 66‐year‐old patient with this psychiatric disease developed parkinsonism and cognitive decline during concomitant treatment with both drugs. The rapid onset of symptoms soon after use of the combination suggested an interaction/using the Karch‐Lasagna criteria, the interaction was judged to be definite. What is new and Conclusion: Their evidence on a pharmacokinetic drug interaction between the two drugs is conflicting but possible underlying mechanisms proposed include CYP3A4 inhibition. As concomitant use of valproate and quetiapine is now quite frequent in bipolar disorder, this potential interaction should be closely monitored, especially in the elderly.