[Effect of posture on spinal cord stimulation in patients with chronic pain syndromes: analysis of energy requirements in different patient postures]

BACKGROUND AND OBJECTIVE

Patients being treated with spinal cord stimulation for chronic pain complain of variable paresthesias, particularly in relation to changes in posture. Such changes affect the great majority of patients with implantable pulse generators, requiring them to use the external programmer for avoidance of painful paresthesias or even to disconnect the generator, leading to loss of pain relief. The aim of this study was to determine the relationship between the pulse charge needed for stimulation and the patient's different postures.

MATERIAL AND METHODS

Observational study of 70 patients treated with spinal cord stimulation in the following postures and situations: decubitus position, standing, seated, and walking. With the patients standing, we analyzed the thresholds of perception, pain, and pain relief, as well as the therapeutic range. Studies were performed in all patients. Later, data were analyzed by anatomical positioning of the stimulator (cervical, thoracic, sacral, occipital, or subcutaneous).

RESULTS

In the analysis of the therapeutic range in the overall group we identified statistically significant differences between decubitus and standing positions and between decubitus position and walking. At the level of the thoracic spine differences were identified between all positions except between standing and walking and between seated and decubitus positions. At the level of the cervical spine, no significant differences were detected. Analysis of the pulse charge showed a significant difference in the decubitus position, in which less charge was needed to achieve satisfactory stimulation. When electrodes implanted at the cervical and thoracic levels were compared, differences were found between standing and seated positions (P=.04) but none between decubitus position or walking and the other positions.

CONCLUSION

Stimulation systems are not currently designed to adapt to changes in distance between the electrodes and nerve fibers. Improvements are required in this respect.

Adaptation and validation of the Spanish version of the Mood Disorder Questionnaire for the detection of bipolar disorder

OBJECTIVE

The Mood Disorder Questionnaire (MDQ) is an instrument for the detection of patients with bipolar disorder (BD). The original English version is validated in both the psychiatric and the general population, but a validated Spanish version is not yet available. Psychometric properties of the Spanish adaptation of the MDQ in psychiatry are described.

METHODS

The MDQ is a self-administered questionnaire comprising a list of 13 hypomanic symptoms and two questions about concurrence of symptoms and functional impairment caused by the symptoms. We selected patients from 15 psychiatric outpatient departments, diagnosed with BD type I and II (BDI and BDII) and major depression (MD) according to DSM-IV-TR criteria (concurrent validity instrument). A control group of healthy subjects (HS) was selected. The patient-selection criteria included stability of the disorder and pharmacological treatment. The MDQ was administered to 236 subjects, distributed among the four groups, on two occasions, four weeks apart. We analysed the internal consistency, test-retest reliability, and discriminative capacity of the MDQ for the detection of patients with BD.

RESULTS

Concurrent validity based on diagnosis according to DSM-IV-TR was 0.83. The internal consistency, evaluated by Cronbach's alpha, was 0.90. The mean (SD) number of affirmative responses by group was: 9.8 (2.4) for BDI, 8.5 (2.8) for BDII, 2.7 (2.2) for MD, and 1.02 (1.9) for HS. Statistically significant differences between all the groups were found (Kruskal-Wallis test, p < 0.001). Concurrent validity using the diagnostic variable was 0.83. Test-retest reliability was 0.92. We analysed the scale's discriminative capacity, revealing a sensitivity value of 0.60 [95% confidence interval (CI) = 0.51-0.69] and a specificity value of 0.98 (95% CI = 0.94-0.99) in the detection of BD. The positive and negative probability ratios were 35.5 and 2.4, respectively. If we consider only seven positive responses as the discriminative criterion, sensitivity increases to 0.81 (95% CI = 0.73-0.88), the specificity value is 0.95 (95% CI = 0.89-0.98) and the positive and negative probability quotients are 16 and 5.3.

CONCLUSIONS

The psychometric characteristics of the Spanish version are similar to those of the original version. In the Spanish adaptation of the MDQ, seven positive responses to hypomanic symptoms show a good discriminative capacity for BD in patients attending psychiatric outpatient facilities; therefore, this cut-off score is proposed for the detection of BD in psychiatric outpatients.

Measuring secretion in chromaffin cells using electrophysiological and electrochemical methods

Our present understanding of exocytosis of catecholamines has benefited tremendously from the arrival of single-cell electrochemical methods (amperometry and voltammetry), electrophysiological techniques (whole-cell and patch capacitance) and from the combination of both techniques (patch amperometry). In this brief review, we will outline the strengths and limitations of amperometric and electrophysiological methods and highlight the major contribution obtained with the use of these techniques in chromaffin cells.

Results of PAL feasibility test in primary health care facilities in four regions of Bolivia

SETTING

Primary health care (PHC) centres in four Bolivian regions.

OBJECTIVES

To test the feasibility and impact of training general practitioners (GPs) in standard case management of respiratory conditions in patients aged > or =5 years.

DESIGN

Comparison of the results of two surveys: the baseline survey before training and the impact survey after training on standard guidelines on case management of respiratory conditions.

RESULTS

A total of 78 GPs working in 65 health centres participated in both surveys. The baseline survey registered 1033 respiratory patients and the impact survey 1154. The patients were comparable in sex distribution, previous visits, duration of symptoms and clinical diagnoses. The differences were significant in age distribution, concomitant diseases and risk factors. As a result of training, referrals to a higher level decreased by 34.6% and the proportion of tuberculosis (TB) suspects identified increased by 30%. The number of drugs prescribed per patient decreased by 16.2%. The average cost of prescription of any drug per patient dropped by 32.3%.

CONCLUSION

Training in the standard practical approach to lung health guidelines improved the quality and reduced the cost of treatment of respiratory diseases at PHC units. Training should be an integral part of a comprehensive managerial approach for the implementation of case management guidelines.

Microsomal prostaglandin E synthase-1, which is not coupled to a particular cyclooxygenase isoenzyme, is essential for prostaglandin E(2) biosynthesis in vascular smooth muscle cells

BACKGROUND

Prostaglandin (PG) E(2) induces expression of matrix metalloproteinases and angiogenic factors, thereby contributing to plaque instability.

OBJECTIVE

To study the influence of cyclooxygenase (COX) and PGE synthase (PGES) isoenzyme expression on PGE(2) and PGI(2) biosynthesis in vascular smooth muscle cells (VSMC) in culture.

METHODS

Cells were treated with human recombinant IL-1beta over different periods of time. Expression of PGI synthase, and COX and PGES isoenzymes was determined by real-time reverse transcriptase polymerase chain reaction and immunoblotting. Biosynthesis of prostanoids from exogenous or endogenous substrate was analyzed by high-performance liquid chromatography or enzyme-immunoassay after incubation of cells with labeled arachidonic acid or thrombin, respectively.

RESULTS

Cytosolic PGES and microsomal PGES (mPGES) -1 and -2 were expressed in VSMC. PGES activity was mainly linked to mPGES-1. IL-1beta induced COX-2 and mPGES-1 with a different time course. VSMC ability to synthesize PGE(2) and PGI(2) fitted mPGES-1 and COX-2 expression, respectively. The ability of VSMC to produce PGI(2) was downregulated by mPGES-1 expression and was restored when mPGES-1 expression was silenced. Results from COX-1 and COX-2 silencing and selective inhibition showed that both COX-1 and COX-2 were involved in the biosynthesis of PGE(2) and their relative contribution depended on the time of incubation with IL-1beta.

CONCLUSIONS

mPGES-1 is the main PGES responsible for PGE(2) biosynthesis by VSMC and its induction downregulates VSMC ability to produce PGI(2.) These results support the concept that under inflammatory conditions VSMC could significantly contribute to plaque instability and that mPGES-1 may be a target for therapeutic intervention in patients with cardiovascular risk.

IL-1beta induces VEGF, independently of PGE2 induction, mainly through the PI3-K/mTOR pathway in renal mesangial cells

Vascular endothelial growth factor (VEGF) could play a relevant role in angiogenesis associated with chronic allograft nephropathy. Interleukin-1beta (IL-1beta) has a key role in inflammatory response. It induces prostaglandin (PG) E2, which is involved in VEGF release by some normal and tumor cells. In the present work, we studied the effect of IL-1beta on VEGF release by rat mesangial cells, the transduction signal, and whether or not PGE2 is involved in this effect. IL-1beta induced a time-dependent formation of VEGF (analyzed by enzyme-linked immunosorbent assay) and PGE2 (analyzed by enzyme immunoassay). The latter correlated with microsomal-PGE-synthase (mPGES)-1 expression rather than with cyclooxygenase (COX)-2 in terms of protein, determined by Western blotting. No effect of IL-1beta on COX-1, cytosolic PGES, or mPGES-2 expression was observed. Indomethacin exerted a nonsignificant effect on IL-1beta-induced VEGF, and exogenously added PGE2 exhibited a nonsignificant stimulatory effect on VEGF formation. SB 203580, a p38 mitogen-activated protein kinase inhibitor, weakly inhibited the induction of VEGF by IL-1beta in a concentration-dependent manner, whereas LY 294002, a phosphoinoside 3-kinase (PI3-K) inhibitor, and rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, strongly inhibited both IL-1beta- and tumor necrosis factor-alpha-induced VEGF formation in a concentration-dependent manner. Rapamycin also decreased glomerular VEGF levels in the anti-Thy1.1 model of experimental glomerulonephritis. In conclusion, the PI3-K-mTOR pathway seems to be essential in cytokine-induced release of VEGF in mesangial cells.

Evaluation of a rapid culture method for tuberculosis diagnosis: a Latin American multi-center study

SETTINGS

Tuberculosis (TB) diagnostic laboratories in Latin America.

OBJECTIVES

Evaluation of thin-layer agar (TLA) compared to Löwenstein-Jensen (LJ) culture for the diagnosis of TB.

DESIGN

Phase II prospective study in six laboratories. Samples included sputum and extra-pulmonary specimens from patients with a clinical diagnosis of TB. Respiratory samples were decontaminated using NaOH/ NALC; all samples were centrifuged, stained with Ziehl-Neelsen for acid-fast bacilli (AFB), cultured on LJ and TLA and identified according to recommended procedures. Sensitivity and likelihood ratios (LR), growth detection time and contamination rate were calculated for both media.

RESULTS

A total of 1118 clinical specimens were studied. Cultures detected Mycobacterium tuberculosis in all AFB-positive samples, whereas for AFB-negative specimens LJ detected 3.2% and TLA 4.4%. Sensitivity was 92.6% (95%CI 87.9-95.9) and 84.7% (95%CI 78.8-89.0) for TLA and LJ, respectively. Positive and negative LRs were similar. Contamination was 5.1% for TLA and 3.0% for LJ. Median time to detection of a positive culture was 11.5 days (95%CI 9.3-15.0) for TLA and 30.5 days (95%CI 26.9-39.0) for LJ (P < 0.0001).

CONCLUSION

Difference in the characteristics of the participating laboratories, the disease prevalence and the number and type of specimens processed did not affect the overall performance of TLA as compared to LJ, supporting the robustness of the method and its feasibility in different laboratory settings.

Participation of estradiol and progesterone in the retrograde labeling of pubococcygeus motoneurons of the female rat

Retrograde labeling with horseradish peroxidase conjugated to wheat germ agglutinin showed that the pubococcygeus muscles of the female rat are innervated by a population of motoneurons located in a column approximately 2 mm in length in the central region of lamina IX of the sixth lumbar-first sacral spinal cord segments. These neurons have a dendritic distribution that projects to the lateral, medial and ventral regions of the gray matter. Values for soma size, primary dendrite length and arborization area obtained from intact animals that were in diestrous-2, were significantly reduced following ovariectomy. After hormone priming of the ovariectomized animals with estradiol benzoate and progesterone, an additional injection of estradiol benzoate alone or followed by progesterone increased the labeled length of the primary dendrites distributed to the lateral, but not to the medial or ventral regions of the gray matter in the spinal cord. However, dendritic labeling was not significantly increased when only progesterone was additionally injected. It therefore seems that pubococcygeus muscle motoneurons of the female rat are sensitive to the effects of gonadal hormones.

Effect of carbon and nitrogen sources, pH and temperature on in vitro culture of several isolates of Amanita caesarea (Scop.:Fr.) Pers

Several isolates were obtained from sporocarps of Amanita caesarea (Scop.: Fr.) Pers. associated with Quercus suber and Castanea sativa coming from the southwest of Spain. Culture conditions were optimized for these isolates. The largest radial growth was obtained at pH 6-7, and optimal growth temperature was 24-28 degrees C depending on the isolate. Albumin bovine and nitrate produced the largest patch size diameters, but the greatest mycelium dry weight yields were obtained with ammonium. Mannitol produced the largest radial growth, and mannitol and glucose yielded the biggest mycelium dry weights. Although variations in growth behaviour between isolates were observed, only one internal spacer sequence-restriction fragment length polymorphism type was obtained.

Immediate peritoneal response to bacterial contamination during laparoscopic surgery

BACKGROUND

Several studies have shown that laparoscopic surgery (LS) minimizes surgical trauma and the immune function is better preserved. Another major advantage of LS is the lower incidence of septic complications. However, several in vitro studies have shown that CO(2) severely impairs macrophage physiology. In theory, this would reduce the ability to respond to peritoneal contamination. However, there is some controversy in view of the evidence of a better preserved peritoneal response to sepsis. This study analyzed the early response of the peritoneum to contamination in a CO(2) ambience.

METHODS

A total of 192 CD-1 mice were distributed in three groups: group 1, laparotomy (LAP, n = 64); group 2, CO(2) laparoscopy (CO(2)-LC, n = 64); and group 3, wall lift laparoscopy (WL-LC, n = 64). Mice in each group were randomized to receive 1 ml of Escherichia coli suspension (1 x 10(4) colony-forming units/ml) or saline. Peritoneal fluid was obtained at 1.5, 3, 6, and 12 h after surgery. Monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), and prostaglandin E(2) (PGE(2)) were measured.

RESULTS

MCP-1 levels were significantly greater and higher earlier in group 2 (CO(2)-LC) than in group 1 (LAP) (p < 0.007). Simultaneously, the increment in the traction group (WL-LC, group 3) was significantly higher (p < 0.002) than after laparotomy, with no differences in group 2 (CO(2)-LC). When a contamination was added to the laparotomy subgroup, there was a significant increase compared to the group without contamination (p < 0.5). MCP-1 modifications after contamination in the LAP group were statistically significant and appeared later than in the WL-LC (p < 0.002) and CO(2)-LC groups (p < 0.02). For IL-6, the three models presented a significant increase in the noncontaminated groups. This occurred significantly later in the LAP group. Simultaneously, the increase in IL-6 occurred earlier and was significantly higher in the WL-LC group compared to the LAP group (p < 0.003), without differences between CO(2)-LC and wall lift groups. Significant differences between contaminated and noncontaminated subgroups were only observed in the LC-CO(2) groups. When contaminated, the traction model sustained a higher and earlier rise in IL-6 levels compared to the LAP and LC-CO(2) groups (p < 0.001). For PGE(2), The three models showed a significant increase in PGE(2) levels in the noncontaminated groups. However, there were no significant differences between them. In the contaminated groups, there was no statistical difference between the groups.

CONCLUSION

Despite a transient impairment of the immediate peritoneal response to a septic challenge, the degree of injury with LS is lower than that with open surgery, and abdominal infection can therefore be better controlled.

The inflammatory properties of electronegative low-density lipoprotein from type 1 diabetic patients are related to increased platelet-activating factor acetylhydrolase activity

AIMS/HYPOTHESIS

Chemical and biological characteristics of LDL(-) from type 1 diabetic subjects were analysed. The diabetic patients were studied during poor and optimised glycaemic control.

MATERIALS AND METHODS

Total LDL was subfractionated into electropositive LDL(+) and electronegative LDL(-) by anion exchange chromatography and the lipid and protein composition of the two determined.

RESULTS

LDL(-) differed from LDL(+) in that it had higher triglyceride, non-esterified fatty acids, apoE, apoC-III and platelet-activating factor acetylhydrolase (PAF-AH), as well as lower apoB relative content. No evidence of increased oxidation was observed in LDL(-). LDL(-) increased two-fold the release of interleukin 8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) in endothelial cells, suggesting an inflammatory role. Optimisation of glycaemic control after insulin therapy decreased the proportion of LDL(-), but did not modify the composition of LDL subfractions, except for a decrease in PAF-AH activity in LDL(-). The possibility that LDL(-) could be generated by non-enzymatic glycosylation was studied. Fructosamine and glycated LDL content in LDL subfractions from type 1 diabetic patients was greater than in LDL subfractions isolated from normoglycaemic subjects, and decreased after glycaemic optimisation in both subfractions. However, no difference was observed between LDL(+) and LDL(-) before and after insulin therapy.

CONCLUSIONS/INTERPRETATION

These results provide evidence that LDL(-) is not produced by glycosylation. Nevertheless, LDL(-) from diabetic patients displays inflammatory potential reflected by the induction of chemokine release in endothelial cells. This proatherogenic effect could be related to the high PAF-AH activity in LDL(-).

A catalogue of molecular, physiological and symbiotic properties of soybean-nodulating rhizobial strains from different soybean cropping areas of China

We have analysed 198 fast-growing soybean-nodulating rhizobial strains from four different regions of China for the following characteristics: generation time; number of plasmids; lipopolysaccharide (LPS), nodulation factors (LCOs) and PCR profiles; acidification of growth medium; capacity to grow at acid, neutral, and alkaline pH; growth on LC medium; growth at 28 and 37 degrees C; melanin production capacity; Congo red absorption and symbiotic characteristics. These unbiased analyses of a total subset of strains isolated from specific soybean-cropping areas (an approach which could be called "strainomics") can be used to answer various biological questions. We illustrate this by a comparison of the molecular characteristics of five strains with interesting symbiotic properties. From this comparison we conclude, for instance, that differences in the efficiency of nitrogen fixation or competitiveness for nodulation of these strains are not apparently related to differences in Nod factor structure.

Photochemistry and in vitro phototoxicity studies of levomepromazine (methotrimeprazine), a phototoxic neuroleptic drug

The neuroleptic drug levomepromazine (1, previously known as methotrimeprazine) is photolabile under UV-A and UV-B light in aerobic conditions. Irradiation of a methanol solution of this drug produces one photoproduct, resulting from the oxidation of 1 to its sulfoxide parent. It is demonstrated that photodegradation occurs via type II mechanism involving irreversible trapping of self-photogenerated singlet molecular oxygen. 1 shows a photohemolytic effect on human erythrocytes and photoinducers lipid peroxidation.

[Exocytosis as the mechanism for neural communication. A view from chromaffin cells]

Exocytosis constitutes the main cellular mechanism for secreting neurotransmitters. It entails the fusion of a secretory vesicle with plasma membrane, thus promoting the release of its soluble content. Among the cell models that have provided insight into molecular machinery underlying the succesive steps of exocytosis, adrenal chromaffin cells have taken a prominent place. Exocytosis gave support to the classical quantal theory, which maintains that neurotransmitters are released as discrete packages from the nerve terminals towards the postsynaptic cell. We present here a brief review of the estate of our knowlegments about the secretory vesicle traffic towards the cell membrane and how exocytosis takes place through the so called SNARE hypothesis. We also review the novel mechanisms implicated in the regulation of the late steps of exocytosis as well as their possible role as target for drug therapy

Soils of the Chinese Hubei province show a very high diversity of Sinorhizobium fredii strains

Biodiversity studies of native soybean-nodulating rhizobia in soils from the Chinese Hubei province (Honghu county; pH 8, alluvial soil) have been carried out. Inoculation of an American (Williams) and an Asiatic (Peking) soybean cultivar with eleven soil samples led to the isolation of 167 rhizobia strains. The ratio (%) of slow-/fast-growing isolates was different depending on the trap plant used. All isolates were able to nodulate both cultivars, although the N2-fixation efficiency (measured as plant-top dry weight) was different among them. A total of thirty-three isolates were selected for further characterisation on the basis of physiological parameters, PCR-RFLP of symbiotic genes and Low Molecular Weight RNA, lipopolysaccharide, protein and plasmid profiles. Low Molecular Weight RNA profiling indicates that all the isolates belong to species Sinorhizobium fredii. The dendrogram obtained with the physiological parameters has been useful to classify the isolates at strain level, although plasmid profiling was the most discriminating technique to detect differences among the analysed soybean-rhizobia isolates, showing there is not two isolates identical each other. Plasmid profile analyses also revealed that some of the investigated strains contain low molecular weight plasmids (7-8-kb). They are, to our knowledge, the smallest ever found in rhizobia and they could be the starting point for the construction of the first group of vectors based on a native rhizobia replicon.

Survival of several Rhizobium/Bradyrhizobium strains on different inoculant formulations and inoculated seeds

The effect of a variety factors on the survival of several rhizobia strains on inoculants and inoculated seeds has been evaluated. Since the rhizobia strains showed different cell-density-evolution patterns on peat-based inoculants and on inoculated seeds, several inoculant formulations with highly effective Rhizobium/Bradyrhizobium strains (for Lupinus, Hedysarum, Phaseolus and Glycine max.) were monitored under the following storage conditions: (a) the inoculants were kept refrigerated (at 4 degrees C), or (b) at room temperature (25 degrees C). The effect of water content (30-50%, w/w) in the inoculants as well as that of several seed-coating adhesives were also investigated. Alternative carriers including perlite and vermiculite were tested. For all of the strains, survival on sterile peat-based inoculants was higher than on the corresponding unsterile peat formulation; for the latter, refrigerated storage conditions are recommended to ensure high bacterial densities. The water content of the inoculants had a differential effect on strain survival depending on the sterility of the peat, such that a high water content was more detrimental when unsterilized peat was employed. The best adherent for rhizobia survival was a gum arabic/water solution. Perlite was as effective as peat in maintaining a high population of rhizobia, at least for 6 months of storage.

Role of thyroid hormones in the maturation and organisation of rat barrel cortex

The influence of thyroid hormones on cortical development was analysed in rat somatosensory cortex. Maternal and foetal hypothyroidism was induced and maintained by methimazole treatment from embryonic day 13 onwards. 5-Bromo-2'-deoxyuridine (BrdU) labelling in hypothyroid rats showed that cell positioning during corticogenesis followed an inside-out pattern. The radial neurogenetic gradients were more diffuse at all ages with respect to normal rats due to the inappropriate location of many cells, including those of the subcortical white matter. Most (62%) of the cells in the subcortical white matter of hypothyroid rats were labelled at embryonic day 15. Nissl staining of the primary somatosensory cortex showed blurred cortical layer boundaries and an abnormal barrel cytoarchitecture. Cytochrome oxidase and peanut agglutinin staining showed that the tangential organisation of the posteromedial barrel subfield and its layer IV specificity was not lost in hypothyroid rats. However the temporal pattern of peanut agglutinin labelling was delayed 3-4 days with respect to normal rats. In hypothyroid rats, the total barrelfield tangential area was reduced by 27% with respect to normal. The total tangential barrel area, corresponding to peanut agglutinin-negative labelling, occupied 77% of the barrelfield area and only 66% in hypothyroid rats. This reduction was larger with cytochrome oxidase staining where the total barrel area occupied 69% of the barrelfield area in normal and 46% in hypothyroid rats. Our data stress the importance of maternal and foetal thyroid hormones during development, and demonstrate the irreversible effects that maternal and foetal hypothyroidism may have on the intrinsic organisation and maturation of the neocortex.

Protracted expression of serotonin transporter and altered thalamocortical projections in the barrelfield of hypothyroid rats

In humans, thyroid hormone deficiency during development causes severe neurological diseases but the underlying mechanisms are unclear. We have examined the effects of thyroid hormones on the development of somatosensory thalamocortical projections, by inducing hypothyroidism in rats by methimazole treatment at embryonic day 13 and subsequent thyroidectomy at postnatal day 6 (P6). Initial development of the thalamocortical projections and their tangential and laminar patterning were similar in normal and hypothyroid rats from birth to P4. The tangential spread of the thalamocortical arbors is reduced in hypothyroid rats after P4, paralleling the overall cortical atrophy. Anterograde tracing and single axon reconstructions indicate that thalamic afferents reached layer IV but that they had fewer and shorter branches, with a 42% reduction in the number of boutons. The transient serotonin (5-HT) immunostaining and 5-HT transporter (5-HTT) expression were both prolonged by 5 days in hypothyroid rats. This does not reflect a delayed maturation of the thalamus because other transiently expressed genes such as the vesicular monoamine transporter and the 5-HT1B receptor are not modified. Protracted 5-HTT expression also occurred in other areas with transient expression, but no changes were observed in the raphe nuclei where the 5-HTT is expressed permanently. Thus, thyroid hormones appear to be important in regulating the extinction of the 5-HTT in nonserotoninergic neurons. The transient stabilization of 5-HT reuptake in hypothyroid rats could affect the growth of thalamic axons. Our data stress the importance of maternal and foetal thyroid hormones for the normal development of sensory systems.

Co-inoculation with Bacillus sp. CECT 450 improves nodulation in Phaseolus vulgaris L

The strain Bacillus sp. CECT 450 increased nodulation on bean (Phaseolus vulgaris L.) when co-inoculated with Rhizobium tropici CIAT 899. This positive effect occured under controlled conditions on perlite-vermiculite, sand, or in a mixture of soil and sand. This increase was also observed in a field assay. Nodulation kinetic studies suggested that the synergistic effect is pronounced during the latter stages of cultivation. In contrast, the same bacteria co-inoculated with Bradyrhizobium japonicum USDA 110 reduced nodulation on soybean (Glycine max (L.) Merr.). Inoculation with Bacillus sp. CECT 450 alone had no effect on bean plants, but reduced root growth in soybean. The survival of Bacillus sp. CECT 450 on inoculated seeds was high, even when inoculated seeds were maintained for several months at room temperature.

Effect of pH and soybean cultivars on the quantitative analyses of soybean rhizobia populations

Quantitative analyses of fast- and slow-growing soybean rhizobia populations in soils of four different provinces of China (Hubei, Shan Dong, Henan, and Xinjiang) have been carried out using the most probable number technique (MPN). All soils contained fast- (FSR) and slow-growing (SSR) soybean rhizobia. Asiatic and American soybean cultivars grown at acid, neutral and alkaline pH were used as trapping hosts for FSR and SSR strains. The estimated total indigenous soybean-rhizobia populations of the Xinjiang and Shan Dong soil samples greatly varied with the different soybean cultivars used. The soybean cultivar and the pH at which plants were grown also showed clear effects on the FSR/SSR rations isolated from nodules. Results of competition experiments between FSR and SSR strains supported the importance of the soybean cultivar and the pH on the outcome of competition for nodulation between FSR and SSR strains. In general, nodule occupancy by FSRs significantly increased at alkaline pH. Bacterial isolates from soybean cultivar Jing Dou 19 inoculated with Xinjiang soil nodulate cultivars Heinong 33 and Williams very poorly. Plasmid and lipopolysaccharide (LPS) profiles and PCR-RAPD analyses showed that cultivar Jing Dou 19 had trapped a diversity of FSR strains. Most of the isolates from soybean cultivar Heinong 33 inoculated with Xinjiang soil were able to nodulate Heinong 33 and Williams showed very similar, or identical, plasmid, LPS and PCR-RAPD profiles. All the strains isolated from Xinjiang province, regardless of the soybean cultivar used for trapping, showed similar nodulation factor (LCO) profiles as judged by thin layer chromatographic analyses. These results indicate that the existence of soybean rhizobia sub-populations showing marked cultivar specificity, can affect the estimation of total soybean rhizobia populations indigenous to the soil, and can also affect the diversity of soybean rhizobial strains isolated from soybean nodules.

Determinants of drug-resistant tuberculosis: analysis of 11 countries

SETTING

Eleven countries/territories.

OBJECTIVES

Global information on the determinants of drug-resistant tuberculosis (TB) based on representative data is not available. We therefore studied the relationship between demographic characteristics, prior TB treatment, and human immunodeficiency virus (HIV) infection with anti-tuberculosis drug resistance.

METHODS

Population-based representative data on new and previously treated patients with TB collected within an international drug resistance surveillance network.

RESULTS

Of 9,615 patients, 8,222 (85.5%) were new cases of TB and 1,393 (14.5%) were previously treated cases. Compared with new cases, previously treated cases were significantly more likely to have resistance to one (OR = 2.5,95% CI 2.1-3.0; P < 0.001), two (OR = 4.6, 95%CI 3.7-5.6; P < 0.001), three (OR = 11.5, 95%CI 8.6-15.3; P < 0.001), and four (OR = 18.5, 95% CI 12.0-28.5; P < 0.001) drugs. An approximately linear increase in the likelihood of having multidrug-resistant tuberculosis (MDR-TB) was observed as the total time (measured in months) of prior anti-tuberculosis treatment increased (P < 0.001, chi2 for trend). In multivariate analysis, prior TB treatment for 6-11 months (OR = 7.6, 95% CI 2.6, 22.4; P < 0.001) and > or = 12 months (OR 13.7, 95% CI 4.5-41.6; P < 0.001), but not HIV positivity, was associated with MDR-TB.

CONCLUSION

This study shows that prior but ineffective treatment is a strong predictor of drug resistance, and that HIV is not an independent risk factor for MDR-TB. The association between length of treatment and drug resistance may reflect longer treatment as a result of treatment failure in patients with drug resistance; it may also reflect irregular prior treatment for TB, leading to drug resistance.

Mesangial cells release untransformed prostaglandin H2 as a major prostanoid

BACKGROUND

Prostaglandin H2 (PGH2) is the precursor of the other prostanoids and exhibits a vasoconstricting activity. Glomerular mesangial cells are an important source of vasoactive prostanoids in kidney. Hence, the present investigation focused on the release of untransformed PGH2 by rat glomerular mesangial cells (RGMCs).

METHODS

Synthesis of prostanoid by resting and interleukin-1beta (IL-1beta)-treated (overnight) RGMCs from exogenous or endogenous arachidonic acid (AA) was assessed by high-performance liquid chromtography or enzyme immunoassay, respectively. Cyclo-oxygenase isoforms were determined by Western blotting. Release of untransformed PGH2 from exogenous AA was evaluated in RGMCs and intact glomeruli as the difference of PGF2alpha formed in the incubations performed in the presence and in the absence of SnCl2 or measuring the ability of aspirin-treated platelets to form thromboxane B2 (TXB2) in mixed incubations of platelets and RGMCs or glomeruli.

RESULTS

The prostanoids formed by RGMCs were PGE2, PGF2alpha, PGI2 and PGD2. SnCl2 totally deviated formation of PGE2 and PGD2 toward PGF2alpha in resting RGMCs, whereas PGE2 was only partially deviated toward PGF2alpha in IL-1beta-treated RGMCs. The PGE2/PGD2 ratio in resting RGMCs was similar to that expected for nonenzymatic isomerization of PGH2, whereas this ratio was higher in IL-1beta-treated RGMCs, suggesting the induction of PGE synthase by IL-1beta. Aspirin-treated platelets formed TXB2 when either RGMCs or intact glomeruli were present in the incubation and formation of TXB2 was approximately fourfold higher with IL-1beta-treated RGMCs or glomeruli.

CONCLUSIONS

RGMCs and intact glomeruli released substantial amounts of untransformed PGH2, which was enhanced following exposure to IL-1beta.

In vitro based index of topical anti-inflammatory activity to compare a series of NSAIDs

The aim of the present work was to generate an index to predict topical efficiency of a series of nonsteroidal anti-inflammatory drugs (NSAIDs): indomethacin, diclofenac, ketoprofen, piroxicam, tenoxicam and ketorolac. This index took into account both biopharmaceutic and pharmacodynamic aspects. The biopharmaceutic aspect, based on the maximal flux (J(m)), was determined experimentally from transdermal studies carried out with human skin in previous work. The pharmacodynamic aspect, based on the ability to inhibit cyclooxygenase-2 (COX-2) in vitro, was determined by incubating human dermal fibroblasts in culture, pre-treated with phobol-12-myristate-13-acetate (PMA) for 6 h, with 25 microM [(14)C]-arachidonic acid (AA) in the presence of several drug concentrations. The most potent inhibitor of COX-2 activity in induced fibroblasts was diclofenac while indomethacin, ketoprofen and ketorolac were approximately equipotent. Piroxicam and tenoxicam were inhibitors at higher concentrations. Based on the proposed index of the topical anti-inflammatory activity (ITAA) diclofenac, ketorolac, ketoprofen and indomethacin exhibited acceptable efficiency for external use. However, piroxicam and tenoxicam showed the lowest topical anti-inflammatory activity of the series assayed. In conclusion, indomethacin ketorolac, ketoprofen and diclofenac have shown good intrinsic feasibility for formulation into topical pharmaceutical forms. However, for dermatological formulations of oxicams, use of penetration enhancers may be unavoidable.

Effect of an imidazolineoxyl nitric oxide on prostaglandin synthesis in experimental shock: possible role of nitrogen dioxide in prostacyclin synthase inactivation

The effect of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a nitric oxide (NO) scavenger that yields nitrogen dioxide (NO(2)) in a rat endotoxemia model was investigated. Endotoxin (lipopolysaccharide [LPS]) increased NO synthase (NOS) activity and inducible NOS expression measured in lung and plasma levels of nitrite/nitrate, 6-oxo-prostaglandin (PG) F(1alpha), thromboxane B(2), and PGF(2alpha). Infusion of cPTIO significantly reduced LPS-induced mean arterial blood pressure decline and mortality and selectively reduced LPS-induced 6-oxo-PGF(1alpha) plasma levels and prostacyclin synthase (PGIS) activity measured in the lung and aorta. In vitro, PGIS activity in aorta rings was not modified by SNAP (NO donor), cPTIO slightly inhibited the enzyme but not in the presence of L-N(G)-monomethyl arginine, and SNAP in combination with cPTIO significantly inhibited PGIS. Thus, cPTIO may be beneficial in endotoxic shock because of NO scavenging and PGIS inactivation, which could be mediated by NO(2).

Human vascular smooth muscle cells but not endothelial cells express prostaglandin E synthase

In a previous work, we postulated that endothelial cells possess only the following 2 enzymes involved in prostanoid synthesis: cyclooxygenase and prostacyclin synthase. The present work focused on investigating the expression of prostaglandin (PG) E synthase (PGES) in vascular cells. After incubation of vascular smooth muscle cells (SMCs) and human umbilical vein endothelial cells (HUVECs) with [(14)C]arachidonic acid, the profile of prostanoid synthesis was assessed by HPLC. Untransformed PGH(2) released by the cells was evaluated as the difference in the formation of PGF(2alpha) in the incubations performed in the presence and in the absence of SnCl(2). Resting SMCs and SMCs stimulated with phorbol 12-myristate 13-acetate (PMA), lipopolysaccharide (LPS), interleukin (IL)-1beta, and tumor necrosis factor (TNF)-alpha formed PGE(2) and PGI(2) (evaluated as 6-oxo-PGF(1alpha)), and in the presence of SnCl(2) only a small amount of PGE(2) was deviated toward PGF(2alpha). In contrast, resting and stimulated HUVECs produced PGI(2), PGE(2), PGF(2alpha), and PGD(2), and SnCl(2) completely diverted PGE(2) and PGD(2) toward PGF(2alpha). Reverse transcriptase-polymerase chain reaction analysis shows that mRNA encoding for PGES was not present in HUVECs and in endothelial cells from saphenous vein. Nevertheless, PGES was expressed in SMCs and induced by IL-1beta and TNF-alpha, and by PMA and LPS, although to a lesser extent. Whereas SMC stimulation led to an increase in the synthesis of PGE(2) and PGI(2) but not of untransformed PGH(2), stimulation of endothelial cells resulted in an enhanced release of the vasoconstricting prostanoid PGH(2).

Transcellular formation of thromboxane A(2) in mixed incubations of endothelial cells and aspirin-treated platelets strongly depends on the prostaglandin I-synthase activity

Despite an almost total suppression of platelet cyclooxygenase (COX) by aspirin, as monitored ex vivo, incomplete suppression of thromboxane (Tx)A(2) metabolite excretion has been detected in some patients with unstable angina treated with low doses of aspirin. A plausible explanation for this finding is the transcellular formation of TxA(2) by platelets from prostaglandin H(2) released by endothelial cells. We recently reported that probably only COX and PGI-synthase (PGIS) are involved in the biosynthesis of prostanoids in endothelial cells. The present work was thus focused to ascertain the dependence of the transcellular biosynthesis of TxA(2), by endothelial cells and aspirin-treated platelets, on the relative activity of these enzymes. Synthesis of eicosanoids from exogenous and endogenous arachidonic acid (AA) by mixed incubations of human umbilical vein endothelial cells (HUVEC) in culture and aspirin-treated platelets were determined by HPLC and enzyme immune assay. The ratio of COX to PGIS activities was modified in HUVEC by treatment with interleukin-1beta (IL-1beta). Transcellular formation of TxA(2) was only relevant when HUVEC overexpressed COX-2 (monitored by RT-PCR and Western blotting), and in these conditions TxA(2) formation started 2 minutes after substrate addition. Progression curves showed that half-times (t(1/2)) of the COX and PGIS activity were 2.73 and 0.47 minutes, respectively, in resting HUVEC, whereas these values for IL-1beta-treated cells were 1.33 and 0.07 minutes, respectively, indicating that expression of COX-2 increased the rate of PGIS "suicide" inactivation. Collectively, these results indicated that not only enhanced COX activity but also substantial PGIS inactivation was required for significant transcellular biosynthesis of TxA(2).

[The Mini-Mental State Examination as a selected diagnostic test for dementia: a Colombian population study. GENECO]

INTRODUCTION

Folstein's Mini Mental State Examination (MMSE) is widely used as screening test for cognitive impairment.

OBJECTIVE

To test a Spanish version of the MMSE in a population of high illiteracy rate.

MATERIAL AND METHODS

Population-based survey of a stratified random sample of urban and rural residents of five regions of Colombia, followed by neurological and neuropsychological evaluation of suspect cases (phase 2). Dementia was diagnosed using DSM-IV criteria.

RESULTS

1,611 subjects age 50 or older filled out both the WHO Protocol for Epidemiologic Studies of Neurological Disorders and a Spanish version of the MMSE; 55.2% of them had three or less years of schooling; 536 individuals with scores below cutoff points were sent to phase 2. Of the population with satisfactory scores in MMSE 366 (34.0%) were evaluated by neurologists to exclude other neurological conditions. Twelve cases of dementia were diagnosed among individuals with scores below cutoff point and one among subjects with high scores. Age-adjusted prevalence was 8.1 per thousand subjects age 50 or over (95% CI: 3.7-12.5); and 34.2 per thousand for ages 75 or over (95% CI: 12.2-56.2). Sensitivity and specificity were 92.3 and 53.7%; 16 of the 19 questions show significant differences (p < 0.001) according to educational level. A gender gap is significant in low educational levels (p < 0.001) but not in subjects with more than five years of schooling.

CONCLUSIONS

MMSE scores correlated closely with level of education. Low specificity leads to many non-demented subjects with low educational status requiring further investigation.

Characteristic distribution of HTLV type I and HTLV type II carriers among native ethnic groups in South America

To confirm the geographic and ethnic segregation of HTLV-I and HTLV-II carriers in native populations in South America, we have conducted a seroepidemiological study of native populations in South America, including HTLV-I carriers distributed among seven ethnic groups in the Andes highlands of Colombia, Peru, Bolivia, Argentina, and Chile, and two ethnic groups on Chiloe Island and Easter Island; and HTLV-II carriers distributed among seven ethnic groups of the lowlands along the Atlantic coast of Colombia, Orinoco, Amazon, and Patagonia, and one ethnic group on Chiloe Island. The incidence rate of HTLV-I and HTLV-II carriers varied among the ethnic groups, ranging from 0.8 to 6.8% for HTLV-I seropositivity and from 1.4 to 57.9% for HTLV-II seropositivity. A new HTLV-I focus was found among the Peruvian Aymara (1.6%), the Bolivian Aymara (5.3%) and Quechua (4.5%), the Argentine Puna (2.3%), and the Chilean Atacama (4.1%), while on HTLV-II focus was found among the Brazilian Kayapo (57.9%), the Paraguayan Chaco (16.4%), and the Chilean Alacalf (34.8%) and Yahgan (9.1%). The distribution of HTLV-I/II foci showed a geographic clustering of HTLV-I foci in the Andes highlands and of HTLV-II foci in the lowlands of South America. It was thus suggested that South American natives might be divided into two major ethnic groups by HTLV-I and HTLV-II carrier state.

Phase I-II study of 5-fluorouracil, recombinant interferon alpha2a, and cisplatin in combination with external beam radiation therapy followed by surgery in patients with locally advanced carcinoma of the esophagus

Multimodality therapy has been demonstrated to be superior to external beam radiation therapy and possibly surgery alone for the treatment of carcinoma of the esophagus. The combination of 5-fluorouracil (5-FU), cisplatin, and recombinant interferon alpha2a (IFN) has yielded 65% response rates in metastatic and regionally advanced carcinoma of the esophagus. A phase I-II study was performed to assess the feasibility of combining 5-FU, IFN, and cisplatin with external beam radiation therapy followed by surgery in potentially resectable patients. Eligibility included biopsy-proven stage II-III squamous cell or adenocarcinoma of the esophagus with no prior therapy. External beam radiation therapy was administered concurrently with chemotherapy beginning on day 1, 5 days per week, twice a day with 1.5 Gy/fraction to a total dose of 45 Gy. 5-FU was administered at 750 mg/m2 on days 1, 8, 15, 22, and 29 after the administration of IFN and cisplatin. IFN was given at a dose of 6 million units subcutaneously three times per week beginning on day 1. Dose levels I, II, and III of cisplatin were 25, 30, and 35 mg/m2 administered on days 1, 8, 15, 22, and 29. The sequence of administration was IFN followed by cisplatin followed immediately by 5-FU. Dose escalation between patient cohorts occurred if 0/3 or < or = 1/6 patients had dose-limiting toxicity, i.e., grade II-III toxicity attributable to cisplatin. A phase II trial was planned using the maximum tolerated dose of cisplatin determined from the phase I trial. Patients who successfully completed therapy underwent thoracic exploration to resect residual disease. Twelve patients were enrolled; all were eligible. The demographics of the population were median age, 60 years (range, 44-77); nine male and three female patients; nine squamous cell carcinoma, one adenocarcinoma, and two adenosquamous histology; stage II:III, 2:10. Grade 3-4 toxicities included granulocytopenia (12 patients), thrombocytopenia (six), anemia (three), infection (six), diarrhea (two), mucositis (two), and renal and hepatic toxicities (one). Five patients had a clinical complete response, among whom four underwent surgery. At surgery, one patient had no evidence of residual disease and three patients had microscopic disease only. Two patients had progressive disease and five could not complete the therapy because of toxicities. Two patients are alive and disease free at 25 and 23 months, respectively. This regimen, though active, demonstrated an unfavorable toxicity profile and cannot be recommended for further study.

Leishmania amazonensis infection induces changes in the electrophysiological properties of macrophage-like cells

Whole cell patch-clamp recordings were used to study the electrical properties of the macrophage-like cell line J774.1, after infection with Leishmania amazonensis. Infection induced a significant increase in cell size and membrane capacitance, suggesting that parasite invasion leads to the addition of plasma membrane to the host cell. By 24 hr after infection, the host cell membrane potential was significantly more hyperpolarized than control cells, and this difference remained for the subsequent 72 hr post-infection. The hyperpolarization was paralleled by an increase in the density of inward rectifying K(+) currents. The shape of the conductance vs. voltage curve, the kinetic properties and the pharmacological profile of these currents were not significantly altered by infection. These results suggest that infection by L. amazonensis causes an increase in the number of functional inward rectifying K(+) channels, leading to hyperpolarization of the host cell membrane.

Amino acid residues involved in the catalytic mechanism of NAD-dependent glutamate dehydrogenase from Halobacterium salinarum

The pH dependence of kinetic parameters for a competitive inhibitor (glutarate) was determined in order to obtain information on the chemical mechanism for NAD-dependent glutamate dehydrogenase from Halobacterium salinarum. The maximum velocity is pH dependent, decreasing at low pHs giving a pK value of 7.19+/-0.13, while the V/K for l-glutamate at 30 degrees C decreases at low and high pHs, yielding pK values of 7.9+/-0.2 and 9.8+/-0.2, respectively. The glutarate pKis profile decreases at high pHs, yielding a pK of 9. 59+/-0.09 at 30 degrees C. The values of ionization heat calculated from the change in pK with temperature are: 1.19 x 10(4), 5.7 x 10(3), 7 x 10(3), 6.6 x 10(3) cal mol-1, for the residues involved. All these data suggest that the groups required for catalysis and/or binding are lysine, histidine and tyrosine. The enzyme shows a time-dependent loss in glutamate oxidation activity when incubated with diethyl pyrocarbonate (DEPC). Inactivation follows pseudo-first-order kinetics with a second-order rate constant of 53 M-1min-1. The pKa of the titratable group was pK1=6.6+/-0.6. Inactivation with ethyl acetimidate also shows pseudo-first-order kinetics as well as inactivation with TNM yielding second-order constants of 1.2 M-1min-1 and 2.8 M-1min-1, and pKas of 8.36 and 9.0, respectively. The proposed mechanism involves hydrogen binding of each of the two carboxylic groups to tyrosyl residues; histidine interacts with one of the N-hydrogens of the l-glutamate amino group. We also corroborate the presence of a conservative lysine that has a remarkable ability to coordinate a water molecule that would act as general base.

[Adjuvant therapy with a glycoprotein IIb-IIa inhibitor (abciximab) in coronary angioplasties with a high thrombotic risk]

INTRODUCTION

We retrospectively studied our experience with adjunctive therapy with glycoprotein IIb-IIIa inhibitor (abciximab) on patients with a high risk of thrombotic complications during coronary angioplasty (PTCA).

PATIENTS AND METHODS

From September 1996 to November 1997, we performed PTCA in 210 patients, and abciximab was given to 38 (18%) of them. The interventions were urgent (primary PTCA in acute myocardial infarction) in 55% of the cases. The mean age of patients was 68.6 +/- 12 years and 71% were male. The reasons for coronary intervention were: acute myocardial infarction in 21 patients (55.3%), unstable angina in 9 (23.7%) and stable angina in 8 (21%). Coronary stents were implanted in 13 patients (34%) and an intra aortic balloon pump was used in 4 (11%). The reasons for using abciximab were: thrombus containing lesion: 22 (57.9%); other type B2/C lesion characteristics: 6 (15.9%); acute closure post balloon PTCA: 9 (23.7%), sub-acute stent thrombosis: 1 (2.6%). Oral acetilsalicilic acid and intravenous heparin were given to all patients at the beginning of the intervention. The mean APTT was 124 +/- 32 seconds at the end of the procedure.

RESULTS

The arterial sheaths (8 French) were removed six hours after procedure, according to the normalisation of APTT values. Angiographic success in this group of patients was 100%. One patient died during hospitalisation due to left ventricular failure. There was no need for repeated angioplasty or coronary bypass grafting during hospital stay. The main complications related to the use of abciximab were: bleeding (requiring transfusion) in four patients 10.5%); severe thrombocytopenia (< 50,000 platelets/mm3): 1 (2.6%): cardiac tamponade (requiring pericardiocentesis): 1 (2.6%) and pseudo-aneurysm of femoral artery (requiring vascular surgery): 1 (2.6%).

CONCLUSIONS

The use of abciximab as adjunctive therapy in this small group of patients undergoing coronary interventions with high risk of thrombotic complications is associated with high procedural success, but at the expense of high rates of bleeding complications. Therefore, special care must be applied during and after the procedure to enhance the safety of the patients treated with this drug.

Operation of glyoxylate cycle in halophilic archaea: presence of malate synthase and isocitrate lyase in Haloferax volcanii

The occurrence of the glyoxylate cycle has not previously been demonstrated in any of the Archaea. In halophilic archaea, only isocitrate lyase activity has been detected. The halophilic archaeon Haloferax volcanii was tested for the presence of the other key enzyme of this pathway, malate synthase. High activities of this enzyme were detected when the carbon source was acetate. Both glyoxylate cycle key enzymes, isocitrate lyase and malate synthase, from Hf. volcanii were purified and characterized.

Rate of vasoconstrictor prostanoids released by endothelial cells depends on cyclooxygenase-2 expression and prostaglandin I synthase activity

This study was undertaken to investigate the enzymatic regulation of the biosynthesis of vasoconstrictor prostanoids by resting and interleukin (IL)-1(beta)stimulated human umbilical vein endothelial cells (HUVECs). Biosynthesis of eicosanoids in response to IL-1beta, exogenous labeled arachidonic acid (AA), or histamine, as well as their spontaneous release, was evaluated by means of HPLC and RIA. HUVECs exposed to IL-1beta produced prostaglandin (PG) I2 for no longer than 30 seconds after the substrate was added irrespective of the cyclooxygenase (COX) activity, whereas the time course of PGE2 and PGD2 formation was parallel to the COX activity. The ratio of PGE2 to PGD2 produced by HUVECs was similar to that obtained by purified COX-1 and COX-2. Production of PGF2alpha from exogenous AA was limited and similar in both resting and IL-1beta-treated cells. PGF2alpha was the main prostanoid released into the medium during exposure to IL-1beta, whereas when HUVECs treated with IL-1beta were stimulated with histamine or exogenous AA, PGE2 was released in a higher quantity than PGF2alpha. PGF2alpha released into the medium during treatment with IL-1beta and the biosynthesis of PGE2 and PGD2 in response to exogenous AA or histamine increased with COX-2 expression, whereas this did not occur in the case of PGI2. We observed that PGI synthase (PGIS) mRNA levels were not modified by the exposure to IL-1beta, but the enzyme was partially inactivated. When SnCl2 was added to the incubation medium, the transformation of exogenous AA-derived PGH2 into PGE2 and PGD2 was totally diverted toward PGF2alpha. Overall, these results support the conclusions that PGE2 and PGD2 (and also probably PGF2alpha) were nonenzymatically derived from PGH2 in HUVECs. The concept that a high ratio of PGH2 was released by the IL-1beta-treated HUVECs and isomerized outside the cell into PGE2 and PGD2 was supported by the biosynthesis of thromboxane B2 by COX-inactivated platelets, indicating the uptake by platelets of HUVEC-derived PGH2. The IL-1beta-induced increase in the release of PGH2 by HUVECs was suppressed by the COX-2-selective inhibitor SC-58125 and correlated with both COX-2 expression and PGIS inactivation. An approach to the mechanism of inactivation of PGIS by the exposure to IL-1beta was performed by using labeled endoperoxides as substrate. The involvement of HO. in the PGIS inactivation was supported by the fact that deferoxamine, pyrrolidinedithiocarbamate, DMSO, mannitol, and captopril antagonized the effect of IL-1beta on PGIS to different degrees. The NO synthase inhibitor NG-monomethyl-L-arginine also antagonized the PGIS inhibitory effect of IL-1beta, indicating that NO. was also involved. NO. reacts with O2-. to form peroxynitrite, which has been reported to inactivate PGIS. Homolytic fission of the O-O bond of peroxynitrite yields NO2. and HO.. The fact that 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), which reacts with NO. to form NO2., dramatically potentiated the IL-1beta effect suggests that NO2. could be a species implicated in the inactivation of PGIS. Cooperation of HO. was supported by the fact that DMSO partially antagonized the effect of carboxy-PTIO. Although our results on the exact mechanism of the inactivation of PGIS caused by IL-1beta were not conclusive, they strongly suggest that both NO. and HO. were involved.