Same but different - pseudo-pectin in the charophytic alga Chlorokybus atmophyticus.

All land-plant cell walls possess hemicelluloses, cellulose and anionic pectin. The walls of their cousins, the charophytic algae, exhibit some similarities to land plants' but also major differences. Charophyte 'pectins' are extractable by conventional land-plant methods, although they differ significantly in composition. Here, we explore 'pectins' of an early-diverging charophyte, Chlorokybus atmophyticus, characterising the anionic polysaccharides that may be comparable to 'pectins' in other streptophytes. Chlorokybus 'pectin' was anionic and upon acid hydrolysis gave GlcA, GalA and sulphate, plus neutral sugars (Ara≈Glc>Gal>Xyl); Rha was undetectable. Most Gal was the l-enantiomer. A relatively acid-resistant disaccharide was characterised as ß-d-GlcA-(1→4)-l-Gal. Two Chlorokybus 'pectin' fractions, separable by anion-exchange chromatography, had similar sugar compositions but different sulphate-ester contents. No sugars were released from Chlorokybus 'pectin' by several endo-hydrolases [(1,5)-α-l-arabinanase, (1,4)-ß-d-galactanase, (1,4)-ß-d-xylanase, endo-polygalacturonase] and exo-hydrolases [α- and ß-d-galactosidases, α-(1,6)-d-xylosidase]. 'Driselase', which hydrolyses most land-plant cell wall polysaccharides to mono- and disaccharides, released no sugars except traces of starch-derived Glc. Thus, the Ara, Gal, Xyl and GalA of Chlorokybus 'pectin' were not non-reducing termini with configurations familiar from land-plant polysaccharides (α-l-Araf, α- and ß-d-Galp, α- and ß-d-Xylp and α-d-GalpA), nor mid-chain residues of α-(1→5)-l-arabinan, ß-(1→4)-d-galactan, ß-(1→4)-d-xylan or α-(1→4)-d-galacturonan. In conclusion, Chlorokybus possesses anionic 'pectic' polysaccharides, possibly fulfilling pectic roles but differing fundamentally from land-plant pectin. Thus, the evolution of land-plant pectin since the last common ancestor of Chlorokybus and land plants is a long and meandering path involving loss of sulphate, most l-Gal and most d-GlcA; re-configuration of Ara, Xyl and GalA; and gain of Rha.

The Prevalence of Systems Thinking in Supply Chain Management: a Systematic Literature Review.

In light of the maelstrom that global Supply Chains must struggle with, we contend that Systems Thinking in Supply Chain Management can be an enabling factor. Systems Thinking can support problem-solving in the reactive crisis mode that practitioners find themselves in, let alone when seeking ways to improve the end-to-end Supply Chain. This paper determines the prevalence of Systems Thinking methodologies within the literature and confirms if these contributions provide benefits to Supply Chain Management beyond the dyad through empirical research? Given the challenges of realising supply chain-wide progression, are these contributions supporting the discipline in pursuing industry advancement strategies? A systematic literature review methodology was employed, evaluating ninety-seven peer-reviewed papers regarding the breadth; from suppliers' supplier to customers customer, and depth; from literature review to empirical research. Five research outcomes are identified, resulting in an established hypothesis. We argue that a positive correlation between Systems Thinking Maturity and Supply Chain Performance leads to a more significant opportunity to go beyond the dyad. The hypothesis led to a research construct that advocates the need to determine empirically whether a correlation exists between Systems Thinking Maturity and Supply Chain Performance.

Fruit softening: evidence for pectate lyase action in vivo in date (Phoenix dactylifera) and rosaceous fruit cell walls.

BACKGROUND AND AIMS: The programmed softening occurring during fruit development requires scission of cell wall polysaccharides, especially pectin. Proposed mechanisms include the action of wall enzymes or hydroxyl radicals. Enzyme activities found in fruit extracts include pectate lyase (PL) and endo-polygalacturonase (EPG), which, in vitro, cleave de-esterified homogalacturonan in mid-chain by ß-elimination and hydrolysis, respectively. However, the important biological question of whether PL exhibits action in vivo had not been tested. METHODS: We developed a method for specifically and sensitively detecting in-vivo PL products, based on Driselase digestion of cell wall polysaccharides and detection of the characteristic unsaturated product of PL action. KEY RESULTS: In model in-vitro experiments, pectic homogalacturonan that had been partially cleaved by commercial PL was digested to completion with Driselase, releasing an unsaturated disaccharide ('ΔUA-GalA'), taken as diagnostic of PL action. ΔUA-GalA was separated from saturated oligogalacturonides (EPG products) by electrophoresis, then subjected to thin-layer chromatography (TLC), resolving ΔUA-GalA from higher homologues. The ΔUA-GalA was confirmed as 4-deoxy-ß-l-threo-hex-4-enopyranuronosyl-(1→4)-d-galacturonic acid by NMR spectroscopy. Driselase digestion of cell walls from ripe fruits of date (Phoenix dactylifera), pear (Pyrus communis), rowan (Sorbus aucuparia) and apple (Malus pumila) yielded ΔUA-GalA, demonstrating that PL had been acting in vivo in these fruits prior to harvest. Date-derived ΔUA-GalA was verified by negative-mode mass spectrometry, including collision-induced dissociation (CID) fragmentation. The ΔUA-GalA:GalA ratio from ripe dates was roughly 1:20 (mol mol-1), indicating that approx. 5 % of the bonds in endogenous homogalacturonan had been cleaved by in-vivo PL action. CONCLUSIONS: The results provide the first demonstration that PL, previously known from studies of fruit gene expression, proteomic studies and in-vitro enzyme activity, exhibits enzyme action in the walls of soft fruits and may thus be proposed to contribute to fruit softening.

Characterisation of the non-oxidative degradation pathway of dehydroascorbic acid in slightly acidic aqueous solution.

Although l-ascorbate (vitamin C) is an important biological antioxidant, its degradation pathways in vivo remain incompletely characterised. Ascorbate is oxidised to dehydroascorbic acid, which can be either hydrolysed to diketogulonate (DKG) or further oxidised. DKG can be further degraded, oxidatively or non-oxidatively. Here we characterise DKG products formed non-enzymically and non-oxidatively at 20 °C and at a slightly acidic pH typical of the plant apoplast. High-voltage electrophoresis revealed at least five products, including two novel CPLs (epimers of 2-carboxy-l-threo-pentonolactone), which slowly interconverted with CPA (2-carboxy-l-threo-pentonate). One of the two CPLs has an exceptionally low pKa. The CPL structures were supported by MS [(C6H7O7)-] and by 1H and 13C NMR spectroscopy. Xylonate and its lactone also appeared. Experiments with [1-14C]DKG showed that all five products (including the 5-carbon xylonate and its lactone) retained DKG's carbon-1; therefore, most xylonate arose by decarboxylation of CPLs or CPA, one of whose -COOH groups originates from C-2 or C-3 of DKG after a 'benzilic acid rearrangement'. Since CPLs appeared before CPA, a DKG lactone is probably the main species undergoing this rearrangement. CPA and CPL also form non-enzymically in vivo, where they may be useful to researchers as 'fingerprints', or to organisms as 'signals', indicating a non-oxidative, slightly acidic biological compartment.

Montbresides A-D: antibacterial p-coumaroyl esters of a new sucrose-based tetrasaccharide from Crocosmia × crocosmiiflora (montbretia) flowers.

Crocosmia × crocosmiiflora (montbretia) flowers yielded four esters (montbresides A-D) of a new sucrose-based tetrasaccharide, 3-O-ß-d-glucopyranosyl-4´-O-α-d-rhamnopyranosyl-sucrose [ß-d-Glc-(1 → 3)-α-d-Glc-(1↔2)-ß-d-Fru-(4 ← 1)-α-d-Rha]. All four possess O-p-coumaroyl residues on C-3 of fructose and C-4 of α-glucose, plus O-acetyl residues on C-2 and C-3 of rhamnose and C-6 of fructose. Montbresides A and B are additionally O-acetylated on C-1 of fructose. The p-coumaroyls are trans- in montbresides A and C and cis- in B and D. Elemental compositions were determined from MS data, and structures from 1D and 2D NMR spectra. Monosaccharide residues were identified from selective 1D TOCSY spectra and TLC, and acylation sites from 2D HMBC spectra. Enantiomers were distinguished by enzymic digestion. Montbretia flower extracts were cytotoxic against six human cancerous cell-lines, but purified montbresides lacked cytotoxicity. Each montbreside displayed antibacterial activity against Staphylococcus aureus (minimal inhibitory concentration ~6 µg/ml). Montbretia is a potential source of new cytotoxins and antibacterial agents.

The pectic disaccharides lepidimoic acid and ß-d-xylopyranosyl-(1→3)-d-galacturonic acid occur in cress-seed exudate but lack allelochemical activity.

BACKGROUND AND AIMS: Cress-seed (Lepidium sativum) exudate exerts an allelochemical effect, promoting excessive hypocotyl elongation and inhibiting root growth in neighbouring Amaranthus caudatus seedlings. We investigated acidic disaccharides present in cress-seed exudate, testing the proposal that the allelochemical is an oligosaccharin-lepidimoic acid (LMA; 4-deoxy-ß-l-threo-hex-4-enopyranuronosyl-(1→2)-l-rhamnose). METHODS: Cress-seed exudate was variously treated [heating, ethanolic precipitation, solvent partitioning, high-voltage paper electrophoresis and gel-permeation chromatography (GPC)], and the products were bioassayed for effects on dark-grown Amaranthus seedlings. Two acidic disaccharides, including LMA, were isolated and characterized by electrophoresis, thin-layer chromatography (TLC) and nuclear magnetic resonance (NMR) spectroscopy, and then bioassayed. KEY RESULTS: Cress-seed exudate contained low-Mr, hydrophilic, heat-stable material that strongly promoted Amaranthus hypocotyl elongation and inhibited root growth, but that separated from LMA on electrophoresis and GPC. Cress-seed exudate contained ∼250 µmLMA, whose TLC and electrophoretic mobilities, susceptibility to mild acid hydrolysis and NMR spectra are reported. A second acidic disaccharide, present at ∼120 µm, was similarly characterized, and shown to be ß-d-xylopyranosyl-(1→3)-d-galacturonic acid (Xyl→GalA), a repeat unit of xylogalacturonan. Purified LMA and Xyl→GalA when applied at 360 and 740 µm, respectively, only slightly promoted Amaranthus hypocotyl growth, but equally promoted root growth and thus had no effect on the hypocotyl:root ratio, unlike total cress-seed exudate. CONCLUSIONS: LMA is present in cress seeds, probably formed by rhamnogalacturonan lyase action on rhamnogalacturonan-I during seed development. Our results contradict the hypothesis that LMA is a cress allelochemical that appreciably perturbs the growth of potentially competing seedlings. Since LMA and Xyl→GalA slightly promoted both hypocotyl and root elongation, their effect could be nutritional. We conclude that rhamnogalacturonan-I and xylogalacturonan (pectin domains) are not sources of oligosaccharins with allelochemical activity, and the biological roles (if any) of the disaccharides derived from them are unknown. The main allelochemical principle in cress-seed exudate remains to be identified.

(1)H nuclear magnetic resonance spectroscopy-based metabonomic study in patients with cirrhosis and hepatic encephalopathy.

AIM: To identify plasma metabolites used as biomarkers in order to distinguish cirrhotics from controls and encephalopathics. METHODS: A clinical study involving stable cirrhotic patients with and without overt hepatic encephalopathy was designed. A control group of healthy volunteers was used. Plasma from those patients was analysed using (1)H - nuclear magnetic resonance spectroscopy. We used the Carr Purcell Meiboom Gill sequence to process the sample spectra at ambient probe temperature. We used a gated secondary irradiation field for water signal suppression. Samples were calibrated and referenced using the sodium trimethyl silyl propionate peak at 0.00 ppm. For each sample 128 transients (FID's) were acquired into 32 K complex data points over a spectral width of 6 KHz. 30 degree pulses were applied with an acquisition time of 4.0 s in order to achieve better resolution, followed by a recovery delay of 12 s, to allow for complete relaxation and recovery of the magnetisation. A metabolic profile was created for stable cirrhotic patients without signs of overt hepatic encephalopathy and encephalopathic patients as well as healthy controls. Stepwise discriminant analysis was then used and discriminant factors were created to differentiate between the three groups. RESULTS: Eighteen stabled cirrhotic patients, eighteen patients with overt hepatic encephalopathy and seventeen healthy volunteers were recruited. Patients with cirrhosis had significantly impaired ketone body metabolism, urea synthesis and gluconeogenesis. This was demonstrated by higher concentrations of acetoacetate (0.23 ± 0.02 vs 0.05 ± 0.00, P < 0.01), and b-hydroxybutarate (0.58 ± 0.14 vs 0.08 ± 0.00, P < 0.01), lower concentrations of glutamine (0.44 ± 0.08 vs 0.63 ± 0.03, P < 0.05), histidine (0.16 ± 0.01 vs 0.36 ± 0.04, P < 0.01) and arginine (0.08 ± 0.01 vs 0.14 ± 0.02, P < 0.03) and higher concentrations of glutamate (1.36 ± 0.25 vs 0.58 ± 0.04, P < 0.01), lactate (1.53 ± 0.11 vs 0.42 ± 0.05, P < 0.01), pyruvate (0.11 ± 0.02 vs 0.03 ± 0.00, P < 0.01) threonine (0.39 ± 0.02 vs 0.08 ± 0.01, P < 0.01) and aspartate (0.37 ± 0.03 vs 0.03 ± 0.01). A five metabolite signature by stepwise discriminant analysis could separate between controls and cirrhotic patients with an accuracy of 98%. In patients with encephalopathy we observed further derangement of ketone body metabolism, impaired production of glycerol and myoinositol, reversal of Fischer's ratio and impaired glutamine production as demonstrated by lower b-hydroxybutyrate (0.58 ± 0.14 vs 0.16 ± 0.02, P < 0.0002), higher acetoacetate (0.23 ± 0.02 vs 0.41 ± 0.16, P < 0.05), leucine (0.33 ± 0.02 vs 0.49 ± 0.05, P < 0.005) and isoleucine (0.12 ± 0.02 vs 0.27 ± 0.02, P < 0.0004) and lower glutamine (0.44 ± 0.08 vs 0.36 ± 0.04, P < 0.013), glycerol (0.53 ± 0.03 vs 0.19 ± 0.02, P < 0.000) and myoinositol (0.36 ± 0.04 vs 0.18 ± 0.02, P < 0.010) concentrations. A four metabolite signature by stepwise discriminant analysis could separate between encephalopathic and cirrhotic patients with an accuracy of 87%. CONCLUSION: Patients with cirrhosis and patients with hepatic encephalopathy exhibit distinct metabolic abnormalities and the use of metabonomics can select biomarkers for these diseases.

Sugar composition of the pectic polysaccharides of charophytes, the closest algal relatives of land-plants: presence of 3-O-methyl-D-galactose residues.

BACKGROUND AND AIMS: During evolution, plants have acquired and/or lost diverse sugar residues as cell-wall constituents. Of particular interest are primordial cell-wall features that existed, and in some cases abruptly changed, during the momentous step whereby land-plants arose from charophytic algal ancestors. METHODS: Polysaccharides were extracted from four charophyte orders [Chlorokybales (Chlorokybus atmophyticus), Klebsormidiales (Klebsormidium fluitans, K. subtile), Charales (Chara vulgaris, Nitella flexilis), Coleochaetales (Coleochaete scutata)] and an early-diverging land-plant (Anthoceros agrestis). 'Pectins' and 'hemicelluloses', operationally defined as extractable in oxalate (100 °C) and 6 m NaOH (37 °C), respectively, were acid- or Driselase-hydrolysed, and the monosaccharides analysed chromatographically. One unusual monosaccharide, 'U', was characterized by (1)H/(13)C-nuclear magnetic resonance spectroscopy and also enzymically. KEY RESULTS: 'U' was identified as 3-O-methyl-D-galactose (3-MeGal). All pectins, except in Klebsormidium, contained acid- and Driselase-releasable galacturonate, suggesting homogalacturonan. All pectins, without exception, released rhamnose and galactose on acid hydrolysis; however, only in 'higher' charophytes (Charales, Coleochaetales) and Anthoceros were these sugars also efficiently released by Driselase, suggesting rhamnogalacturonan-I. Pectins of 'higher' charophytes, especially Chara, contained little arabinose, instead possessing 3-MeGal. Anthoceros hemicelluloses were rich in glucose, xylose, galactose and arabinose (suggesting xyloglucan and arabinoxylan), none of which was consistently present in charophyte hemicelluloses. CONCLUSIONS: Homogalacturonan is an ancient streptophyte feature, albeit secondarily lost in Klebsormidium. When conquering the land, the first embryophytes already possessed rhamnogalacturonan-I. In contrast, charophyte and land-plant hemicelluloses differ substantially, indicating major changes during terrestrialization. The presence of 3-MeGal in charophytes and lycophytes but not in the 'intervening' bryophytes confirms that cell-wall chemistry changed drastically between major phylogenetic grades.

The reported pain coping strategies of pediatric burn survivors-does a correlation exist between coping style and development of anxiety disorder?

Unresolved pediatric pain, both acute and chronic, has been associated with negative short- and long-term physical and mental health outcomes. This study sought to determine whether an association existed between self-reported pain coping skills and anxiety levels in a cohort of pediatric burn patients, and whether gender would influence their responses. The sample comprised burn-injured children in attendance at one of three mature burn camp sites. The self-report measures utilized included the 41-item Screen for Child Anxiety Related Disorders Child Version and the 39-item Pain Coping Questionnaire. Parental consent was obtained. A psychologist administered the measures. Participants included 187 youth, mean age 12.4 ± 2.4 years, girls (n = 89) boys (n = 98) with 67% reporting visible burn scars. Among boys, the use of Internalizing Coping Strategies was moderately correlated with elevated scores on Panic Disorder symptoms (r = .42, P < .001). Among girls, the use of Internalizing Coping Strategies was associated with elevated Generalized Anxiety (r = .51, P < .001), Panic Disorder (r = .46, P < .001), and Total Anxiety Symptom Scores (r = .49, P < .001). Those children who reported using Behavioral Distraction Strategies did not have any elevated anxiety scores. These findings suggest that burn-injured children, who employ Internalization as their pain coping strategy, may be more vulnerable to the development of long-term anxiety disorder, which, if left untreated may result in a negative psycho/social outcome. Applicability to Practice: Assessment of in-patient pediatric patients with the Pain Coping Questionnaire may help to identify children who are more likely to experience long-term anxiety. Future studies should seek to confirm these findings and determine whether improved pain management and early treatment of anxiety can help to diminish the long-term implications of unhelpful pain strategies and increased anxiety in burn-injured children.

Measuring the burden of pediatric burn injury for parents and caregivers: informed burn center staff can help to lighten the load.

This study sought to identify which commonly experienced burn-related issues parents/caregivers of burn-injured youth deemed most stressful, difficult, and disruptive during their child's initial acute burn care hospitalization, and following the child's discharge. Parents completed an 11-item survey, asking them to rate the difficulty of items regarding their child's burn injury. The scale was created by burn doctors, nurses, and psychologists with an average of 10.5 (SD ± 4.8) years of experience. Items selected were among common parental problems reported in the burn literature. Respondents included 69 parents/caregivers of previously hospitalized, burn-injured youth. The majority were mothers, n = 51 (74%), and n = 34 (49%) were Caucasian. The most represented age group was 37 to 45 years, n = 31 (45%). Children were on average, 6.04 years out from their initial injury. All parents reported their child's pain as the most difficult part of the injury, n = 69 (100%). The second most common issue was the child's first hospital stay. The other two items found to be "very hard" or "pretty hard" were the time spent away from their other children, and feelings of hopelessness in being unable to fix everything for their child. In this study, key parental problems occurred during the child's initial hospitalization. Burn staff cannot alleviate all problems, however, staff education regarding distressing problems faced by parents, as well as possible solutions, can be made available.

Burn-injured youth may be at increased risk for long-term anxiety disorders.

This study aimed to determine the prevalence of long-term anxiety disorder in burn-injured youth. It is well documented that inpatient pediatric burn patients experience heightened anxiety. However, the prevalence of anxiety disorder in pediatric burn survivors warrants further investigation. Participants completed the Screen for Anxiety Related Disorders, a 41-item self-report measuring anxiety disorder symptomatology. Respondents included 197 pediatric burn survivors, 105 boys, 92 girls, who were between 8 and 18 years of age; the mean age was 12.4 ± 2.4 years. Mean age at time of injury was 5.8 ± 3.7 years, with 79% of youth reporting visible scars. There were 77 participants (39%) who screened positive for a possible anxiety disorder with a total anxiety score ≥25, and 28% with a total mean score of ≥30, more specific to the likely presence of anxiety disorder. Nearly half of the participants (44%) reported symptoms indicating the presence of separation anxiety with a mean score of ≥5, and 28% had symptoms indicating the presence of panic disorder and school avoidance disorder. Significant sex differences were observed for anxiety, with girls scoring significantly higher than boys on total anxiety P ≤ .001 and on all four subscales. Youth attending burn camps for ≥5 years reported significantly lower anxiety scores. This study supports the screening of burn-injured youth for anxiety disorder and highlights the importance of educating parents and burn care professionals regarding the symptoms of anxiety disorders. This can help to ensure that pediatric burn survivors receive treatment when anxiety disorder symptoms are present. Screening appears to be especially important for girls.

An unexpectedly lichenase-stable hexasaccharide from cereal, horsetail and lichen mixed-linkage ß-glucans (MLGs): implications for MLG subunit distribution.

Mixed-linkage (1→3),(1→4)-ß-d-glucan (MLG) is a biologically and technologically important hemicellulose, known to occur in three widely separated lineages: the Poales (including grasses and cereals), Equisetum (fern-allies), and some lichens e.g. Iceland moss (Cetraria islandica). Lichenase (E.C. 3.2.1.73) is widely assumed to hydrolyse all (1→4) bonds that immediately follow (1→3) bonds in MLG, generating predominantly the tetrasaccharide ß-d-Glcp-(1→4)-ß-d-Glcp-(1→4)-ß-d-Glcp-(1→3)-d-Glc (G4G4G3G; MLG4), the corresponding trisaccharide (G4G3G; MLG3), and sometimes also laminaribiose (G3G; MLG2). The ratio of the oligosaccharides produced characterises each polysaccharide. We report here that digestion of MLG from barley (Hordeum vulgare), Equisetum arvense and C. islandica by Bacillus subtilis lichenase also yields the unexpectedly stable hexasaccharide, ß-d-Glcp-(1→3)-ß-d-Glcp-(1→4)-ß-d-Glcp-(1→4)-ß-d-Glcp-(1→4)-ß-d-Glcp-(1→3)-d-Glc (G3G4G4G4G3G, i.e. MLG2-MLG4), identified by thin-layer chromatography, gel-permeation chromatography, HPLC (HPAEC), ß-glucosidase digestion, (1)H/(13)C-NMR spectroscopy and mass spectrometry. On HPLC, G3G4G4G4G3G is the major constituent of a peak previously ascribed solely to the nonasaccharide G4G4G4G4G4G4G4G3G. Because it was widely presumed that lichenase would cleave G3G4G4G4G3G to MLG2+MLG4, our data both redefine the substrate specificity of Bacillus lichenase and show previous attempts to characterise MLGs by HPLC of lichenase-digests to be flawed. MLG2 subunits are particularly underestimated; often reported as negligible, they are here shown to be an appreciable constituent of MLGs from all three lineages. We also show that there is no appreciable yield of water-soluble lichenase products with DP>9; potential identities of products previously labelled DP>9 are suggested. Finally, this discovery also provides a opportunity to investigate the spatial distribution of subunits along the MLG chain. We show that MLG2 subunits in barley and Cetraria MLG are not randomly distributed, but predominantly found at the non-reducing end of MLG4 subunits.

Characterisation of oligosaccharides from the chondroitin/dermatan sulphates: (1)H and (13)C NMR studies of oligosaccharides generated by nitrous acid depolymerisation.

The polymers chondroitin sulphate and dermatan sulphate have been fragmented by an anhydrous hydrazine/nitrous acid procedure. The resulting disaccharides from the polymer repeat sequences were reduced with NaBH(4) and purified by ion exchange chromatography. Whereas enzymatic depolymerisation leads to the loss of the distinction between glucuronic and iduronic acids of CS and DS in the resultant disaccharides, nitrous acid depolymerisation retains these structures. Complete (1)H and (13)C NMR data have been derived for the major components which were shown to have the structures: GlcA-(ß1→3)-anTal6S-ol (I) and L-IdoA-(α1→3)-anTal4S-ol (II), where anTal-ol represents (2,5)anhydro-D-talitol and 6S/4S represent O-ester sulphate groups at C-6/C-4 sites.

Impaired gluconeogenesis in a porcine model of paracetamol induced acute liver failure.

AIM: To investigate glucose homeostasis and in particular gluconeogenesis in a large animal model of acute liver failure (ALF). METHODS: Six pigs with paracetamol induced ALF under general anaesthesia were studied over 25 h. Plasma samples were withdrawn every five hours from a central vein. Three animals were used as controls and were maintained under anaesthesia only. Using (1)H NMR spectroscopy we identified most gluconeogenic amino acids along with lactate and pyruvate in the animal plasma samples. RESULTS: No significant changes were observed in the concentrations of the amino acids studied in the animals maintained under anaesthesia only. If we look at the ALF animals, we observed a statistically significant rise of lactate (P < 0.003) and pyruvate (P < 0.018) at the end of the experiments. We also observed statistically significant rises in the concentrations of alanine (P < 0.002), glycine (P < 0.005), threonine (P < 0.048), tyrosine (P < 0.000), phenylalanine (P < 0.000) and isoleucine (P < 0.01). Valine levels decreased significantly (P < 0.05). CONCLUSION: Our pig model of ALF is characterized by an altered gluconeogenetic capacity, an impaired tricarboxylic acid (TCA) cycle and a glycolytic state.

Lunacridine from Lunasia amara is a DNA intercalating topoisomerase II inhibitor.

An ethnobotanical survey of plants used to treat tropical ulcers in Papua New Guinea identified Lunasia amara as possessing anti-Staphylococcus aureus activity. Activity-guided fractionation of the aqueous bark extract resulted in the identification of the quinoline alkaloid lunacridine as the active principle. Lunacridine tends to cyslise at room temperature but the 2'-O-trifluoroacetyl derivative was found to be stable and therefore more suitable for biological assays. The compound exhibited a minimal inhibitory concentration (MIC) of 64 micro g/ml against Staphylococcus aureus NCTC 6571 and activity in the low micromolar range against HeLa and H226 cells; the latter showing signs of caspase-3/7 mediated apoptotic cell death. Experiments with drug resistant strains of Streptococcus pneumoniae suggested topoisomerase as a likely target for the drug in bacteria whilst decatenation assays with human topoisomerase II showed the compound to be a potent inhibitor of this isoform (IC(50)<5 micro M) thus explaining the drug's activity against human cell lines. Both lunacridine and 2'-O-trifluoroacetyl lunacridine exhibited mild DNA intercalation activity giving 50% decrease in ethidium DNA fluorescence at 0.22 and 0.6 mM, respectively, placing the drug amongst the DNA intercalating class of topoisomerase II inhibitors.

Generation and contrasting gas-phase reactivity of 2-(2-alkenylpyrrol-1-yl)phenoxyl and thiophenoxyl radicals.

The pyrrolylacrylates 9 and 10 were synthesised and subjected to flash vacuum pyrolysis (FVP) at 650-700 degrees C to generate the radicals 11 and 18, respectively. The phenoxyl 11 underwent hydrogen capture to give a mixture of the phenol 12 and the pyrrolobenzoxazine 13 in low yields, which were also obtained by a Wittig reaction of the 2-formylpyrrole 14. The thiophenoxyl 18 gave a single major product in 41% yield which was identified as the pyrrolo[1,2-a]quinoline 17 by a sequence of NMR experiments. A mechanism for the formation of 17 by a rearrangement-sulfur extrusion sequence is proposed.

Characterization of oligosaccharides from the chondroitin/dermatan sulfates. 1H-NMR and 13C-NMR studies of reduced trisaccharides and hexasaccharides.

Chondroitin and dermatan sulfate (CS and DS) chains were isolated from bovine tracheal cartilage and pig intestinal mucosal preparations and fragmented by enzymatic methods. The oligosaccharides studied include a disaccharide and hexasaccharides from chondroitin ABC lyase digestion as well as trisaccharides already present in some commercial preparations. In addition, other trisaccharides were generated from tetrasaccharides by chemical removal of nonreducing terminal residues. Their structures were examined by high-field 1H and 13C NMR spectroscopy, after reduction using sodium borohydride. The main hexasaccharide isolated from pig intestinal mucosal DS was found to be fully 4-O-sulfated and have the structure: DeltaUA(beta1-3)GalNAc4S(beta1-4)L-IdoA(alpha1-3)GalNAc4S(beta1-4)L-IdoA(alpha1-3)GalNAc4S-ol, whereas one from bovine tracheal cartilage CS comprised only 6-O-sulfated residues and had the structure: DeltaUA(beta1-3)GalNAc6S(beta1-4)GlcA(beta1-3)GalNAc6S(beta1-4)GlcA(beta1-3)GalNAc6S-ol. No oligosaccharide showed any uronic acid 2-sulfation. One novel disaccharide was examined and found to have the structure: GalNAc6S(beta1-4)GlcA-ol. The trisaccharides isolated from the CS/DS chains were found to have the structures: DeltaUA(beta1-3)GalNAc4S(beta1-4)GlcA-ol and DeltaUA(beta1-3)GalNAc6S(beta1-4)GlcA-ol. Such oligosaccharides were found in commercial CS/DS preparations and may derive from endogenous glucuronidase and other enzymatic activity. Chemically generated trisaccharides were confirmed as models of the CS/DS chain caps and included: GalNAc6S(beta1-4)GlcA(beta1-3)GalNAc4S-ol and GalNAc6S(beta1-4)GlcA(beta1-3)GalNAc6S-ol. The full assignment of all signals in the NMR spectra are given, and these data permit the further characterization of CS/DS chains and their nonreducing capping structures.

A biochemical prognostic model of outcome in paracetamol-induced acute liver injury.

BACKGROUND: The aim of this study was to develop a prognostic model of outcome for patients with paracetamol induced acute liver injury based on admission parameters METHODS: We used a cohort of 97 patients admitted to the Scottish Liver Transplant Unit between 1997 and 1998 to identify biochemical prognostic markers of outcome and thus create a prognostic model. Blood samples were taken on admission for analysis. The model was subsequently validated by testing it on a second cohort of 86 patients admitted between 1999 and 2000. RESULTS: The following were identified as independent variables of poor prognosis (death/ transplant); phenylalanine, pyruvate, alanine, acetate, calcium, haemoglobin and lactate. A prognostic model was then constructed by stepwise forward logistic regression analysis: (400xPyruvate mmols/L)+(50xPhenylalanine (mmols/L)-(4 x Hemoglobin (g/dL). A value of <16 had an accuracy of 93% in predicting death correctly. When applied to the validation cohort this model had a positive predictive value of 91%, a negative predictive value of 94%, a sensitivity of 91%, and a specificity of 94%. On the same population overall, the positive and negative predictive value of the King's criteria were 94% and 93% respectively, whereas their sensitivity and specificity were 88% and 96% respectively. CONCLUSIONS: Using admission characteristics our model is able to identify patients who die from paracetamol overdose fulminant hepatic failure as accurately as King's College criteria, but at a much earlier stage in their condition.

Comparison of bioenergetic activity of primary porcine hepatocytes cultured in four different media.

Primary hepatocytes have extensively been used in biochemical, pharmacological, and physiological research. Recently, primary porcine hepatocytes have been regarded as the cells of choice for bioartificial liver support systems. The optimum culture medium for hepatocytes to be used in such devices has yet to be defined. In this study we investigated the effectiveness of four culture media in driving energy metabolism of primary porcine hepatocytes. The media selected were William's E medium, medium 1640, medium 199, and hepatocyte medium. Cells (3 x 10(10); viability 87 +/- 6%) were isolated from weanling piglets and seeded on 90-mm plates in the above media supplemented with antibiotics and hormones at a density of 8 x 10(6) viable cells per plate. Using 1H NMR spectroscopy we looked at indices of glycolysis, gluconeogenesis. ketogenesis, and ureagenesis on days 2, 4, and 6 of the experiments (n = 9). We also studied urea and albumin synthesis and total P450 content. The examined metabolic pathways of the hepatocytes were maintained by all media, although there were statistically significant differences between them. All media performed well in glycolysis, ureagenesis, and albumin synthesis. William's E medium and medium 199 outperformed the rest in gluconeogenesis. Medium 199 was best in ketogenesis. Overall, medium 199 was the best at driving energy metabolism from its constituent substrates and we think that it preferentially should be used in the culture of primary porcine hepatocytes.

Biochemical prognostic markers of outcome in non-paracetamol-induced fulminant hepatic failure.

BACKGROUND: Fulminant hepatic failure (FHF) is associated with major metabolic disturbances, the onset and severity of which can predict clinical outcome. This study uses admission blood samples to identify early biochemical markers of clinical outcome in patients with non-paracetamol-induced FHF. PATIENTS AND METHODS: Fifty-nine patients admitted to the Scottish Liver Transplant Unit with non-paracetamol-induced FHF were studied. Plasma samples were collected at a median of 5.4 hr after admission to our unit and analyzed using conventional laboratory tests and nuclear magnetic resonance spectroscopy. RESULTS: A total of 19 patients underwent transplantation, 15 patients died without undergoing transplantation, and 25 patients survived with medical management alone. There were significantly lower levels of lactate, alanine, valine, and bilirubin and significantly higher levels of pyruvate and albumin in patients who survived spontaneously compared with the other two groups. By use of multiple logistic regression analysis, an equation was devised that best predicted clinical outcome: 0.5x(albumin [g/L])-2x(lactate [mmol/L])-36x(valine [mmol/L])-38x(pyruvate [mmol/L]). Values of less than 2 were associated with poor clinical outcome and had a positive predictive value of 91%, a negative predictive value of 86%, a sensitivity of 94%, and a specificity of 86% for death or transplantation. This algorithm can be applied on admission, thus expediting decision-making. CONCLUSION: We identified biochemical markers that may be useful in predicting outcome in patients with non-paracetamol-induced FHF and should be evaluated further in a different patient population.