9-cis-Retinoic acid (9cRA), a retinoid X receptor (RXR) ligand, exerts immunosuppressive effects on dendritic cells by RXR-dependent activation: inhibition of peroxisome proliferator-activated receptor gamma blocks some of the 9cRA activities, and precludes them to mature phenotype development

At nanomolar range, 9-cis-retinoic acid (9cRA) was able to interfere in the normal differentiation process from human monocyte to immature dendritic cell (DC) and produced a switch in mature DCs to a less stimulatory mode than untreated cells. 9cRA-treated mature DCs secreted high levels of IL-10 with an IL-12 reduced production. The phenotypic alterations unleashed by 9cRA were similar but not identical to other specific retinoid X receptor (RXR) agonists and to those already reported for rosiglitazone, a PPARgamma activator, on DCs. The simultaneous addition of 9cRA and rosiglitazone on DCs displayed additive effects. Moreover, addition to cultures of GW9662, a specific inhibitor of PPARgamma, or the RXR pan-antagonist HX603, blocked these changes. All these results suggest an activation of PPARgamma-RXR and other RXR containing dimers by 9cRA in DCs. Finally, both GW9662 and HX603 by themselves altered the maturation process unleashed by TNFalpha, poly(I:C) or LPS on human DCs further suggesting that the heterodimer PPARgamma-RXR must fulfill a significant role in the physiological maturation process of these cells in addition to the repressing effects reported till now for this nuclear receptor.     

HIV-1/HAART-Related Lipodystrophy Syndrome (HALS) Is Associated with Decreased Circulating sTWEAK Levels

Background and Objectives

Obesity and HIV-1/HAART–associated lipodystrophy syndrome (HALS) share clinical, pathological and mechanistic features. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a multifunctional cytokine that plays an important role in obesity and related diseases. We sought to explore the relationship between HALS and circulating levels of soluble (s) TWEAK and its scavenger receptor sCD163.

Methods

This was a cross-sectional multicenter study of 120 HIV-1-infected patients treated with a stable HAART regimen; 56 with overt HALS and 64 without HALS. Epidemiological and clinical variables were determined. Serum levels of sTWEAK and sCD163 levels were measured by ELISA. Results were analyzed with Student’s t-test, Mann-Whitney U and χ² test. Pearson and Spearman correlation were used to estimate the strength of association between variables.

Results

Circulating sTWEAK was significantly decreased in HALS patients compared with non-HALS patients (2.81±0.2 vs. 2.94±0.28 pg/mL, p = 0.018). No changes were observed in sCD163 levels in the studied cohorts. On multivariate analysis, a lower log sTWEAK concentration was independently associated with the presence of HALS (OR 0.027, 95% CI 0.001–0.521, p = 0.027).

Conclusions

HALS is associated with decreased sTWEAK levels.     

Sugars as complementary alternative food for the establishment of Nesidiocoris tenuis in greenhouse tomato

Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is an omnivorous generalist predator which is augmentatively released and conserved for control of whiteflies (Hemiptera: Aleyrodidae) and Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in tomato crops. Eggs of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) are often provided as factitious prey to improve the establishment of N. tenuis after its release. We first tested different amounts of E. kuehniella eggs per plant to optimize N. tenuis establishment and then investigated whether the amount of eggs that optimized N. tenuis establishment might be reduced by adding sugars (hydrocapsules filled with 0.5 m sucrose) under walk‐in cage and commercial greenhouse conditions. These experiments demonstrated that the addition of sugar to the diet of N. tenuis could half the amount of E. kuehniella eggs required to establish N. tenuis. Under greenhouse conditions, the progeny of N. tenuis per plant did not differ significantly between E. kuehniella alone or the half amount of E. kuehniella plus hydrocapsules. These results demonstrated that the sugar could partially substitute for E. kuehniella eggs improve establishment of N. tenuis and suggest that natural sugars such as nectar and honeydew might also beneficial.     

Increased Resistance to Quinolones in Campylobacter jejuni: A Genetic Analysis of gyrA Gene Mutations in Quinolone-Resistant Clinical Isolates

Campylobacter jejuni is a frequent cause of enteritis and sometimes it requires antimicrobial therapy. We have studied the evolution of resistance to nine antibiotics from 1990 to 1994 and investigated how frequently gyrA mutations are involved in the acquisition of quinolone resistance. The percentage of chloramphenicol-, clindamycin-, tertracycline- and amoxicillin plus clavulanic acid-resistant strains has remained practically unchanged and erythromycin and gentamicin resistance has decreased, whereas the percentage of ampicillin-, nalidixic acid- or ciprofloxacin-resistant strains has almost doubled in the follow-up period, from 56 to 76% for ampicillin- and from 47.5 to 88% for quinolone-resistant strains. This study clearly shows that a mutation in Thr-86 to Ile or Lys is a frequent mechanism associated with the acquisition of a high level of resistance to quinolones in clinical isolates of C. jejuni.     

Stereoselective metabolic pathways of ketoprofen in the rat: Incorporation into triacylglycerols and enantiomeric inversion

The enantiomeric bioinversion of ketoprofen (KP) enantiomers and their incorporation into triacylglycerols were investigated in the rat (1) in vitro, using liver homogenates, subcellular fractions, and hepatocytes, and (2) in vivo, in different tissue samples after oral administration of the radiolabelled compounds. In liver homogenates or subcellular fractions, the enantiomer (S)-ketoprofen (S-KP) was recovered unchanged, whereas (R)-ketoprofen (R-KP) was partially converted into its Coenzyme A (CoA) thioester and inverted to S-KP. Both processes occurred mainly in the mitochondrial fraction. This supports the mechanism of inversion via stereoselective formation of CoA thioesters of R-KP, already described for other non-steroidal anti-inflammatory drugs. Incorporation into triacylglycerols was detected after incubation with intact hepatocytes in the presence of added glycerol. The process was stereoselective for R-KP vs. S-KP (covalently bound radioactivity 26,742 ± 4,665 dpm/10⁶ cells vs. 6,644 ± 3,179 dpm/10⁶ cells, respectively). However, no incorporation was found in liver samples after oral administration of either R-KP or S-KP. On the contrary, in adipose tissue samples a significant and stereoselective formation of hybrid triacylglycerols was observed: 11,076 ± 2,790 dpm.g⁻¹ for R-KP vs. 660 ± 268 dpm.g⁻¹ for S-KP. The incorporated R/S ratio, higher in adipose tissue (R/S = 17) than in hepatocytes (R/S = 4), indicates that fat may be the main tissue store for the xenobiotic R-KP in rats. © 1996 Wiley-Liss, Inc.     

Oxysterols in cap and core of human advanced atherosclerotic lesions

Objective: Different parts of the advanced atherosclerotic lesion have characteristic differences in lipid content, but the distribution of lipid oxidation products has not been reported. This study provides novel data on oxysterol and hydroxyoctadecadienoic acids quantification in core versus cap. It compares the lipid composition of core and cap to assess the topographical distribution of evidence of lipid oxidation.

Methods: Lipids and oxidised lipids were analysed by gas chromatography (GC) and GC-mass spectrometry (GC-MS) in samples of human atheromatous lipid core and fibrous cap of individual advanced atherosclerotic plaques (Stary, Type V) in necropsy samples.

Results: The total lipid was of course massively greater in the core than in the cap. The oxidation products, cholest-5-en-3β,26-diol (26-OH-CHOL) and cholest-5-en-3β,7β-diol (7β-OH-CHOL) were detected in all the samples. 26-OH-CHOL was more abundant in the core than in the cap when related both to wet weight and to cholesterol. 7β-OH-CHOL levels were significantly higher in the core than in the cap when related to wet weight but not when related to cholesterol. Because the processing included a sodium borohydride reduction step, the 7β-OH-CHOL detected could partly originate from 7-ketocholesterol or 7-hydroperoxy-cholesterol. Several isomeric hydroxyoctadecadienoic acids were detected in both core and cap, more in the cap when related to cholesterol content. Most of the components of the cap showed a high degree of cross-correlation on linear regression analysis, but cross-correlations were weaker for the core. The core samples contained a larger proportion of linoleate relative to oleate than the fibrous cap.

Conclusion: The findings suggest that the different lipid and oxidised lipid contents of cap and core may be due to variations in oxidative activity in different parts of the lesion.     

Spatial Analysis of Twaite Shad,Alosa fallax (Lacepède, 1803), in the Southern North Sea: Application of Non‐Linear Geostatistics as a Tool to Search for Special Areas of Conservation

This study aims to evaluate the suitability of non‐linear geostatistics and indicator kriging (IK) as a tool in environmental impact assessment and nature conservation, in particular to search for potential Special Areas of Conservation (SAC) for the endangered fish species twaite shad, Alosa fallax (Lacepède , 1803) within the German Exclusive Economical Zone (EEZ) of the North Sea. To analyse the spatial distribution of this fish species, data on standardised biomass index (catch per unit effort, c.p.u.e., kg × 30 min^–1) from 1996 to 2001 were used, regarding the third and fourth quarters of each year, respectively. Thereby we assume that the spatial distribution can be described as a time‐invariant process. This assumption is supported by information on annual sampling effort, allocation of hauls and spatial distribution of the positive catches. All indicator variograms obtained for different c.p.u.e. cut‐off values displayed distinct spatial structures, clearly indicating that the indicator variables were spatially autocorrelated. Gaussian models were fitted by least‐squares methods and were evaluated with a goodness‐of‐fit statistic. Subsequently, IK was employed to estimate the probability of exceeding the c.p.u.e. cut‐off values for the twaite shad in the investigation area. These were highest in the Weser‐ and Elbe‐estuary, probably because of migrations of twaite shad to and from estuaries at the time of investigation due to spawning, while within the German EEZ of the North Sea no such areas with increased probabilities could be discerned. Thus, although available data did not allow to identify and implement any SAC in the German EEZ, the methods employed here can be regarded as a promising management tool in biological conservation issues. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Serotonin in body fluids: Characterization of human plasmatic and cerebrospinal fluid pools by means of a new HPLC method

A new HPLC technique for the analysis of picomolar amounts of serotonin (5HT) in plasma and cerebrospinal fluid (CSF) is described. Bufotenin is used as internal standard. Detection is achieved electrochemically or fluorimetrically. The detection limit can be estimated as 50 pg 5HT/mL of either fluid (0.3 picomolar). The method is used to characterize a non-particulate pool of 5HT which is clearly distinct of the platelet pool. Administration of parachlorophenylalanine (PCPA) 300 mg/kg to rats leads to a 90% reduction in the plasmatic pool whereas platelet 5HT is only slightly decreased (3rd day after PCPA) or even increased (7th day after PCPA). Human concentration (n=15) of 5HT in plasma is 2.6 ± 0.9 ng/mL (x ± S.D.). The application of the method to CSF of neurological patients reveals 5HT concentrations ranging from 93 to 962 pg/mL.     

Chromosomal passengers: Toward an integrated view of mitosis

Conclusions The immunocytochemical taxonomy experiments cited above have identified a class of chromosomal antigens whose properties were not predicted by earlier models of mitosis. Our theory describing one possible explanation for the transfer of these antigens from the chromosomes to the spindle midzone at the metaphase: anaphase transition must now be subjected to further experimental tests. The phenotypes of cells microinjected with antibodies to passenger proteins should enable us to identify mitotic processes dependent on these proteins, as in the example of CHO1 antibody blocking mitotic progression (Nislow et al. 1990). In addition, the availability of cDNA clones and high titer antibodies may enable homologues of these components to be identified in organisms in which they can be subjected to genetic analysis.For the time being, we suggest that current views of the relative roles of chromosomes and cytoskeletal components in mitosis may require revision. Our hypothesis takes the current model for the role of the kinetochores in organizing the bipolar mitotic spindle (Kirschner and Mitchison 1986) a step further. The process of assembling a functional spindle and positioning the cleavage furrow may entail a degree of functional cooperation between chromosomes and cytoskeletal components far beyond that envisioned before now.