Influence of malonyl-CoA and palmitate concentration on rate of palmitate oxidation in rat muscle

5-Aminoimidazole-4-carboxamide 1-beta-D-ribofuranoside (AICAR) is taken up by perfused skeletal muscle and phosphorylated to form 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuraosyl-5'-monopho sph ate (analog of 5'-AMP) with consequent activation of AMP-activated protein kinase, phosphorylation of acetyl-CoA carboxylase, decrease in malonyl-CoA, and increase in fatty acid oxidation. This study was designed to determine the effect of increasing levels of palmitate on the rate of fatty acid oxidation. Malonyl-CoA concentration was manipulated with AICAR at different palmitate concentrations. Rat hindlimbs were perfused with Krebs-Henseleit bicarbonate containing 4% bovine serum albumin, washed bovine red cells, 200 microU/ml insulin, 10 mM glucose, and different concentrations of palmitate (0. 1-1.0 mM) without or with AICAR (2.0 mM). Perfusion with medium containing AICAR was found to activate AMP-activated protein kinase in skeletal muscle, inactivate acetyl-CoA carboxylase, and decrease malonyl-CoA at all concentrations of palmitate. The rate of palmitate oxidation increased as a function of palmitate concentration in both the presence and absence of AICAR but was always higher in the presence of AICAR. These results provide additional evidence that malonyl-CoA is an important regulator of the rate of fatty acid oxidation at palmitate concentrations in the physiological range.     

Motivating small construction companies to adopt new technology

Construction companies are increasingly being challenged to transfer and use new technology. However, little investigation has been undertaken on technology transfer from the perspective of the small construction company. A contribution to this underdeveloped area is based on results from an interview survey of seven small UK construction companies. The results stress that the technology which small construction companies tend to transfer more successfully is that which can contribute to the business in a quick, tangible fashion, and which can fit into existing organizational capabilities. Any technology that is too far removed from this ‘comfort zone’ is seen to require too much investment and to contain too much risk, and thus tends to be intuitively and swiftly sifted out. This is in marked contrast to the relevant literature that depicts large companies operating in more complex networks, drawing upon them for new tacit and explicit technologies that support more long-term, formal technology strategies, and which often complement some form of specialized internal research and development capability. The implication for policy is that any technology transfer initiatives need to appreciate and actively manage the different motivations and capabilities of small and large construction companies to absorb and use new technology.

Les entreprises de construction sont de plus en plus appelées à résoudre des questions de transfert et d'utilisation de technologies nouvelles. En revanche, on s'est peu intéressé au point de vue des petites entreprises de ce secteur sur les transferts de technologies. Cette contribution à ce secteur peu développé repose sur les résultats d'une enquête menée en Grande Bretagne auprès de sept petites entreprises de construction. Il en ressort que les technologies que les petites entreprises ont tendance à transférer le mieux sont celles qui peuvent contribuer au développement rapide et tangible des affaires et qui peuvent s'intégrer dans une structure organisationnelle existante. Toute technologie qui s'écarte de trop de cette ‘zone de confort’ est considérée comme nécessitant un investissement trop lourd et présenter trop de risques et a donc tendance à être intuitivement et rapidement mise à l'écart. Cette constatation est en complète opposition avec la littérature qui décrit de grandes entreprises opérant dans le cadre de réseaux plus complexes, attirant vers elles de nouvelles technologies tacites et explicites, compatibles avec des stratégies technologiques officielles à plus long terme et qui, souvent, complètent des formes de recherche interne spécialisée et de capacité de développement. L'implication politique est que toute initiative de transfert de technologie nécessite d'évaluer et de gérer activement les différentes motivations et capacités des petites et grandes entreprises de construction dans leur aptitude à absorber et utiliser de nouvelles technologies.     

The clinical effect of a new infant formula in term infants with constipation: a double-blind,randomized cross-over trial

Background  

Nutrilon Omneo (new formula; NF) contains high concentration of sn-2 palmitic acid, a mixture of prebiotic oligosaccharides and partially hydrolyzed whey protein. It is hypothesized that NF positively affects stool characteristics in constipated infants.     

A fatal case of intrathoracic cuterebriasis in a cat

Isolates of Plasmodium falciparum commonly undergo a large, subtelomeric deletion of the right end of chromosome 9 during in-vitro cultivation. This deletion is usually accompanied by loss of ability to cytoadhere to melanoma cells, loss of a var-gene product from the red-cell surface and a reduction in gametocyte production. However, cytoadherence is stable in the isolate ItG2, remaining after many generations in culture. Deletions in all the non-cytoadherent clones examined have breakpoints within or delete a novel open-reading frame, called the breakpoint open-reading frame (BPORF), that is a unique sequence in the genome. In ItG2, surprisingly, BPORF has been removed by a 15-kb deletion, internal in chromosome 9. These results indicate mechanisms to explain why the deletion of chromosome 9 occurs so frequently and why cytoadherence is stable in ItG2.     

Beta-carotene in HIV infection: an extended evaluation

OBJECTIVE: Several small short-term intervention studies have suggested that beta-carotene supplementation in HIV-infected patients can increase the number of various immune cells including CD4 cells. This prospective double-blinded study was designed to investigate whether beta-carotene supplementation would result in this immuno-enhancement in a larger number of patients over a longer time period. METHODS: HIV-positive patients were randomly assigned to receive either 60 mg beta-carotene orally three times daily or a matched placebo. In addition, all patients received a multivitamin supplement. Patients were evaluated at baseline, 1 month, and 3 months for T-cell quantitative subsets, natural killer cells, HIV p24 antigen, beta-carotene levels, complete blood counts and chemistry batteries. Body weights and Karnofsky scores were evaluated at each visit. RESULTS: Seventy-two patients signed informed consent forms and entered the study. Except for serum beta-carotene concentration, there were no statistically significant differences (P < 0.05) between the treatment (60 mg beta-carotene three times daily and multivitamins) and placebo (placebo and multivitamins) groups at baseline or after either 1 or 3 months of treatment. DISCUSSION: Earlier studies suggesting that beta-carotene supplementation increased levels of immune cells in HIV-infected patients were not replicated in this study. The addition of a multivitamin supplement to both arms of this study may have masked any difference between the two groups. However, on the basis of the results of this study, we would not recommend supplementation with high doses of beta-carotene for HIV-infected patients.     

Designer DNA-binding drugs: the crystal structure of a meta-hydroxy analogue of Hoechst 33258 bound to d(CGCGAATTCGCG)2

An analogue of the DNA binding compound Hoechst 33258, which has the para hydroxyl group altered to be at the meta position, together with the replacement of one benzimidazole group by pyridylimidazole, has been cocrystallized with the dodecanucleotide sequence d(CGCGAATTCGCG)2. The X-ray structure has been determined at 2.2 A resolution and refined to an R factor of 20.1%. The ligand binds in the minor groove at the sequence 5'-AATTC with the bulky piperazine group extending over the CxG base pair. This binding is stabilised by hydrogen bonding and numerous close van der Waals contacts to the surface of the groove walls. The meta-hydroxyl group was found in two distinct orientations, neither of which participates in direct hydrogen bonds to the exocyclic amino group of a guanine base. The conformation of the drug differs from that found previously in other X-ray structures of Hoechst 33258-DNA complexes. There is significant variation between the minor groove widths in the complexes of Hoechst 33258 and the meta-hydroxyl derivative as a result of these conformational differences. Reasons are discussed for the inability of this derivative to actively recognise guanine.     

The effect of chronic hypertension on skin blood flow

OBJECTIVE: To determine whether the cutaneous microvasculature of the spontaneously hypertensive rat (SHR) is affected by chronic hypertension. DESIGN: We used laser Doppler techniques to measure skin blood flow in 22 SHR and in 22 non-hypertensive Wistar-Kyoto (WKY) rats over a 1-year time span, beginning at age 3 months. Sites of measurement included the back, leg, and root of the tail, areas with a predominantly nutritive perfusion, and the plantar surface of the paw, which has a large contribution from large arterioles and venules. Flow was measured at basal skin temperature and at the maximally heat-stimulated condition of 44 degrees C. Systolic tail arterial blood pressures were measured concurrently. RESULTS: At baseline, systolic blood pressures were considerably higher in the SHR (190 +/- 4 mmHg) than they were in the WKY rats (138 +/- 2 mmHg). Skin blood flow values at the three nutritive sites were similar in the two species. However, at 44 degrees C, flow was significantly higher at the paw in the SHR (46.8 +/- 3.5 versus 34.3 +/- 2.2 ml/min per 100 g). We attribute this difference to the effect of high perfusion pressure on large arterioles. During the 1-year measurement period, there was no appreciable change in blood flow in the WKY rats. In contrast, the SHR showed a steady progressive decline in skin blood flow at all sites. The largest decline was at the paw with a rate of fall of about 2.4%/month. After 1 year, there was no difference between paw blood flow in the SHR (27.5 +/- 1.8 ml/min per 100 g) and in the WKY rats (27.6 +/- 1.9 ml/min per 100 g). CONCLUSIONS: Skin blood flow reserve falls in response to chronic hypertension. The rate of fall is greater at sites with significant arteriovenous perfusion that at nutritive sites.     

High-affinity alpha-aminobutyric acid A/benzodiazepine ligands: synthesis and structure-activity relationship studies of a new series of tetracyclic imidazoquinoxalines

A series of tetracyclic imidazoquinoxaline analogs was developed which constrain the carbonyl group of the partial agonist 3-(5-cyclopropyl-1,2,4-oxadiazol-3-yl)-5-[(dimethylamino)carbonyl] - 4,5-dihydroimidazo[1,5-alpha]quinoxaline (2, U-91571) away from the benzene ring. These analogs orient the carbonyl group in the opposite direction of the previously reported full agonist 1-(5- cyclopropyl-1,2,4-oxadiazol-3-yl)-12,12a-dihydroimidazo[1,5- alpha]pyrrolo [2,1-c]quinoxalin-10(11H)-one (3, U-89267). A number of approaches were utilized to form the "bottom" ring of this tetracyclic ring system including intramolecular cyclizations promoted by Lewis acids or base, as well as metal-carbenoid conditions. The size and substitution pattern of the additional ring was widely varied. Analogs within this series had high affinity for the benzodiazepine receptor on the alpha-aminobutyric acid A chloride ion channel complex. From TBPS shift and Cl- current assays, the in vitro efficacy of compounds within this class ranged from antagonists to partial agonists with only 18a identified as a full agonist. Additionally, several analogs were quite potent at antagonizing metrazole-induced seizures indicating possible anticonvulsant or anxiolytic activity. Unlike 3, analogs in this series did not have high affinity for the diazepam insensitive alpha 6 beta 2 delta 2 subtype. These results suggest that either constraining the carbonyl group away from the benzene ring or the greater planarity that results from the additional cyclic structure provides analogs with partial agonist properties and prevents effective interaction with the alpha 6 beta 2 delta 2 subtype.     

Use of randomly amplified polymorphic DNA markers for the genetic analysis of relatedness and diversity in chickens and turkeys

A study involving the use of random amplified polymorphic DNA (RAPD) was conducted to evaluate genetic polymorphism and relatedness within and among four chicken breeds: Araucona, Rhode Island Red, White Leghorn, and White Plymouth Rock, and two turkey populations, a long-term randombred and a commercial strain. A total of 60 random primers were used in the RAPD analyses. Forty-two of the 60 primers tested amplified patterns with at least one polymorphic fragment in one or more of the populations. Six of these 42 primers amplified polymorphic fragments in each of the six strains with a within- and between-population average band-sharing frequency of less than one but above zero (P < 0.05). Differences among the six primers for genetic distance (D) among populations were significant (P < 0.05). A consensus dendogram was therefore developed to show the phylogenetic relationships among the populations. As expected, estimates of D between populations were lowest within species and highest between species. The results provide evidence of the applicability of RAPD to determining genetic relatedness within and among different poultry populations and in developing reproducible markers useful in evaluating individual variation in chickens and turkeys.     

Binding pockets on the surface of human leukocyte elastase and human leukocyte cathepsin G. Implications to the design of inhibitors derived from human C-reactive protein

Analogs of the peptide Val-Thr-Val-Ala-Pro-Val-His-Ile, derived from the primary sequence of the acute phase reactant CRP, i.e. amino acid residues 89-96, were optimized to inhibit the enzymatic activities of human leukocyte elastase (hLE) and human leukocyte cathepsin G (hCG), which are associated with tissue damage occurring in the course of several chronic inflammatory conditions. hLE's major S1 pocket, lined mostly by hydrophobic amino acid residues, was shown by theoretical electrostatic potential calculations to possess some negative charge. This pocket was found to be extremely sensitive towards modifications in the P1 position of CRP derived inhibitors, with valine being the preferred amino acid. In contrast, the corresponding S1 pocket of hCG is large and accepts the positively charged 'aromatic' side chain of histidine, which increases most significantly the capability of CRP derived inhibitors. A prominent positive pocket was observed in the distant S7 region of hLE, which is generated by two exposed positive residues, Arg177 and Arg217, on the enzymes surface. This long range subsite was utilized to increase the hLE inhibitory activity of CRP derived peptide using the natural sequence of CRP, which contains a unique glutamic acid moiety in the P7 position. In contrast to the charged nature of hLE's S7 pocket, the corresponding pocket on the surface of hCG appears to be less prominent. Additional hydrophobic N-terminus modifications of CRP89-96 increased the inhibitory activity towards both enzymes, provided that residues P1 and p7, were designed according to the individual preferences of hLE and hCG. The unique interaction between the negative amino acid side chain of CRP with the positive S7 pocket of hLE as elucidated in this study, and additional subsite preferences may now be used in the design of novel therapeutic substances.