[Bact-Alert automatized system for blood cultures: 5 vs 7 days of incubation. First Argentine multicentre study]

Bact-Alert automatized system for blood cultures: 5 vs 7 days of incubation. First Argentine multicentre study. Between January and December 2001, we analyzed 80,141 blood cultures by the Bact-Alert system (14,960 FAN aerobics, 3,855 FAN anaerobic, 11,114 standards aerobics, 11,367 standards anaerobic, 12,054 pediatrics and 26,791 FAN pediatrics bottles) and 44.235 series from 27.615 patients at eight hospitals of Buenos Aires city, one of La Plata city and three of the Buenos Aires province. A total of 13,657 blood cultures yielded a positive result. Only 181 of them had been detected as positive between the 5th and 7th day of incubation and only 26 (0.19%) had clinical significance (Staphylococcus aureus 3; coagulase negative staphylococci 2; Enterococcus faecalis 1; Streptococcus pneumoniae 2; Campylobacter spp 1; Escherichia coli 1; Enterobacter cloacae 1; Enterobacteraerogenes 1; Citrobacter freundii 1; Klebsiella pneumoniae 1; Proteus mirabilis 1; Serratia marcescens 4; yeasts 7, including one strain of Cryptococcus neoformans). Of the total of contaminants, 38% were isolated by the anaerobic standard (65% were Propionibacterium spp and 29% coagulase negative staphylococci), 31.2% by the FAN aerobic (33.3% difphteroids and 28.9% Bacillus spp), 11.8% by the pediatric, 9% by FAN pediatric, 8.33% by aerobic standard and 1.4% by FAN anaerobic bottle. Our results show that the prolonged incubation of blood cultures for more than 5 days using the Bact-Alert system is unnecessary.

Peroxisome proliferator-activated receptors and the control of inflammation

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors which form a subfamily of the nuclear receptor gene family. This subfamily consists of three isotypes, alpha (NR1C1), gamma (NR1C3), and beta/delta (NRC1C2) with a differential tissue distribution. PPARalpha is expressed primarily in tissues with a high level of fatty acid catabolism such as liver, brown fat, kidney, heart and skeletal muscle. PPARbeta is ubiquitously expressed, and PPARgamma has a restricted pattern of expression, mainly in white and brown adipose tissues, whereas other tissues such as skeletal muscle and heart contain limited amounts. Furthermore, PPARalpha and gamma isotypes are expressed in vascular cells including endothelial and smooth muscle cells and macrophages/foam cells. PPARs are activated by ligands, such as naturally occurring fatty acids, which are activators of all three PPAR isotypes. In addition to fatty acids, several synthetic compounds, such as fibrates and thiazolidinediones, bind and activate PPARalpha and PPARgamma, respectively. In order to be transcriptionally active, PPARs need to heterodimerize with the retinoid-X-receptor (RXR). Upon activation, PPAR-RXR heterodimers bind to DNA specific sequences called peroxisome proliferator-response elements (PPRE) and stimulate transcription of target genes. PPARs play a critical role in lipid and glucose homeostasis, but lately they have been implicated as regulators of inflammatory responses. The first evidence of the involvement of PPARs in the control of inflammation came from the PPARalpha null mice, which showed a prolonged inflammatory response. PPARalpha activation results in the repression of NF-kappaB signaling and inflammatory cytokine production in different cell-types. A role for PPARgamma in inflammation has also been reported in monocyte/macrophages, where ligands of this receptor inhibited the activation of macrophages and the production of inflammatory cytokines (TNFalpha, interleukin 6 and 1beta), although part of the anti-inflammatory effects of these ligands seems to be mediated by a mechanism not involving PPARgamma. All these findings suggest a role of PPARs in the control of the inflammatory response with potential therapeutic applications in inflammation-related diseases.

[Extrahepatic portal hypertension: spleno-portal thrombosis secondary to protein C deficiency]

Portal vein thrombosis (PVT) is the most frequent cause of hypertension portal extrahepatic. It is a rare disorder an the main risk factors are cirrhosis, hepatobiliary malignancies and prothrombotic disorders, which have been identified as major risk. Therapy with anticoagulants must to be considered in acute portal thrombosis or chronic one and proven hypercoagulability. We present the case of a twenty-nine years old patient, with extrahepatic portal hypertension secondary to portal and splenic vein thrombosis, who was diagnosed because of splenomegaly and a coagulation disorder. A protein C deficiency were discovered and anticoagulation and beta-blocker therapy were initiated. One year later the patient had not presented complications concerning to the disease or to the treatment.

Healing of Helicobacter pylori gastric ulcers: only eradication matters

INTRODUCTION

some authors suggest that Helicobacter pylori eradication favors gastric ulcer healing.

OBJECTIVE

to study which factors influence ulcer healing in patients suffering from gastric ulcer with H. pylori infection.

SUBJECTS AND METHODS

a prospective study of 230 patients with gastric ulcer associated to H. pylori infection. Chronic ingestion of non-steroidal anti-inflammatory drugs was considered as an exclusion. In an initial endoscopy, malignancy was histologically excluded and two biopsies each of antrum and body were obtained. Also, ELISA IgG serology and a 13C-urea breath test were performed. Eradication therapy with omeprazole (20 mg twice a day), clarithromycin (500 mg twice a day) and amoxicillin (1 g twice a day) was administered for seven days, followed by omeprazole 20 mg once a day for five more weeks. Endoscopy was repeated after 6 weeks of treatment and breath test was repeated 2 month after completing therapy.

RESULTS

overall gastric ulcer healing was achieved in 80.8% (95% CI: 75-85%) of cases by intention-to-treat, and in 82.6% (77-87%) per protocol. Ulcer healing was achieved in 94.3% (90-97%) of patients with eradication success, but only in 40.8% (28-54%) of patients with eradication failure (p<0.0001). In the multivariate analysis, H. pylori eradication was the only variable that correlated with ulcer healing (odds ratio 24; 95% CI: 10-56; p<0.0001) (x2 model: 64.4; p<0.0001). Additional variables (age, sex, sporadic ingestion of NSAIDs, smoking, previous ulcer disease, ulcer size and location) were not related to healing.

CONCLUSION

H. pylori eradication favors ulcer healing in patients with gastric ulcer, which is an argument in favor of the etiological role of the microorganism in this disease. Other factors did not influence ulcer healing.

In vitro approach to study the influence of the cardiac output distribution on drug concentration

Blood flow is not constant during the day, not only due to cardiac output variation but to the variable blood flow fraction supplied to the organs. To what extent these variations could affect the relative drug concentration between two different tissues, is the purpose of this work. In order to study that, a device was designed which took into account different fluid flows towards two flasks. Connections between flasks and pump are shown in text (figure 1). At the bottom of each flask a non-miscible liquid (dichloromethane: CH2Cl2, 100 mL, places 2 and 3) with the circulating fluid (water, 1350 mL, places 1, A, B) was placed. Malachite Green (MG) was introduced as solute into the system (place 1, 5 mL, 700 mg/L aqueous solution). The pump output was set at 1080 mL/min, serving more fluid (five times) to flask A than to flask B. Samples were drawn from compartments 1, A and B, and from organic compartments, during experiences taking several hours. MG concentrations were colorimetrically measured at 619 nm. Room temperature was between 15-25 degrees C. CH2Cl2 MG concentration ratio([2]/[3]) was similar to fluid flow ratio (sigma/(1-sigma)) all over the experience time. Other experiences changing the stop time, room temperature, CH2Cl2 volumes and places, pump output distribution, led us to different evidences that supported a theoretical model. As a conclusion, the most important feature was that whereas MG concentrations in water (1, A, B) were close, in CH2Cl2 these were very different. So, is drug effect prediction reliable by monitoring free drug concentrations in blood?

Experimental approaches to study PPAR gamma agonists as antidiabetic drugs

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors that are related to retinoid, steroid and thyroid hormone receptors. Since PPARs appear to be closely involved in the regulation of dietary fat storage and catabolism, they have been established as an important target for the treatment of type 2 diabetes and other disorders associated with the high intake of dietary fat. Thiazolidinediones (TZDs) were the first class of compounds to be identified as PPAR gamma-ligands, constituting a new class of antidiabetic drugs that have recently been introduced as therapeutic agents for the treatment of type 2 diabetes mellitus by acting as insulin sensitizers. These compounds improve insulin resistance by increasing cell sensitivity to insulin. In fact, PPAR gamma agonists increase peripheral insulin sensitivity by increasing the transcription of genes, which, in turn, increase glucose uptake, also improving insulin-stimulated glucose disposal in muscle. PPAR gamma agonists increase insulin signaling, reduce circulating levels of free fatty acids and stimulate adipocyte differentiation, thus favoring the formation of smaller, more insulin-sensitive adipocytes. TZDs have been proven effective in different experimental models to evaluate their effectiveness as an antidiabetic agent, and the involvement of PPAR gamma in the pharmacological effects of these compounds has been supported by studies showing an excellent correlation between the hypoglycemic action of these drugs and their affinity for PPAR gamma. Despite this evidence, the site of action and the molecular mechanism of TZDs remain unclear. The aim of the present article was to review and discuss the most relevant pharmacological studies performed in the search for establishing the mechanism of action of antidiabetic TZDs and related compounds acting as PPAR gamma agonists, as well as to summarize those representative experimental approaches currently used to evaluate PPAR gamma agonists as therapeutic agents for the treatment of insulin-resistant type 2 diabetes mellitus.

[Perception of night-time sleep by the surgical patients in an intensive care unit]

Night-time rest of the patients hospitalized in Intensive Care is a very important feature within the health/disease process since it has a direct repercussion on their adequate recovery. The objectives of this investigation are: 1) describe how the surgical patients perceive their night-time sleep in the Polyvalent Intensive Care Unit: 2) compare the subjective perception of the patients with the nursing record in the care plan and analyze the degree of agreement between both assessments. Night-time sleep has been studied in 104 patients; surgery patients from emergencies, patients who are intubated, with previous psychiatric treatment, sleep apnea, drinking habit or impossibility of adequate communication were not included. To measure the patient's perception, the five item sleep questionnaire of Richards-Campbell and the assessment of sleep by the nurse, as well as the remaining variables included in a computerized care plan, were used. The total mean score of the sleep on the first post-operative night was 51.42 mm. When the scores obtained in each one of the questionnaire items are analyzed, it is seen that the sleep profile of these patients has been characterized by being light sleep, with frequent wakenings and generally with little difficulty to go back to sleep when woke op or were awakened. The assessment of the night-time sleep performed by the nurse coincides with the perception of the patients on many occasions, and when there is discrepancy, the nurse has overestimated the patient's sleep.

[Comparison of different detection methods for methicillin resistance in Staphylococcus aureus]

The investigation of methicillin resistance in Staphylococcus aureus (MRSA) is a serious problem for the physician and microbiologist. Accurate and rapid detection is essential for the use of appropriate antimicrobial therapy and for the control of nosocomial spread of the resistant strain. The performance characteristics of the MicroScan Overnight Conventional Pos Combo 12 panels (MOCP), BBL Crystal MRSA ID (CR), E-test and agar screen plate (Muller Hinton agar with oxacillin 6 micrograms/ml and 4% NaCl) (AS) were evaluated for the detection of oxacillin resistance. Thirty S. aureus clinically significant strains with different PFGE (Pulse Field Gel Electrophoresis) banding pattern were tested, and 22 of them were mecA positive by PCR. These strains were also analyzed by mecA and Tn554 polymorphism. All mecA positive strains were classified as methicillin resistant by MOCP and E-test. CR and AS failed to detect oxacillin resistance in 2 strains. One false positive was only detected by E-test. Accurate testing for the presence of MRSA may reduce the need for empiric therapy with vancomycin for patients with staphylococcal infections. According to our results the best performance was obtained with MOCP. However, as a rapid method, CR gave acceptable sensitivity for clinical purposes.

[Temporal spectral evolution of electroencephalogram. Methodology and applications]

INTRODUCTION

The event related potentials (ERPs) allow to study the evolution of the cerebral electric activity related with the diverse sensorial, motors and cognitive processes. However, the ERPs and the spectral analyses based in Fast Fourier Transform, are not able to show the variations along the time of the spectral content of the electroencephalogram (EEG).

OBJECTIVE

The present work will show the necessary methodology to obtain the temporal dynamics of the frequency (TSE) in the EEG, a technique described by Salmelin and Hari (1994) that allows the analysis of the modulations of any spectral band along the time.

SUBJECTS AND METHODS

The presented data correspond to the electroencephalographic registration of 20 human subjects during an experiment of visual spatial attention.

RESULTS

The modulations of the ERPs differ of the observed by the spectral techniques in latency and topography. Likewise, comparing different spectral techniques is proven that the TSE allows to define with more temporal precision the variations on the spectral content.

CONCLUSION

The application of the TSE technique to the same EEG signal that is used for obtaining the ERPs, allows the inclusion of the variable time in the spectral analysis of the EEG, what can be crucial to understand the physiological bases of some neuropathologies.

Increase in hepatic expression of SREBP-2 by gemfibrozil administration to rats

It is well known that gemfibrozil increases the biliary output of cholesterol and phospholipids, but we have little knowledge about the impact these changes have on liver cholesterol and phospholipid biosynthetic pathways. In the present study, no changes were detected in liver lipids and CTP:phosphocholine cytidylyltransferase after gemfibrozil administration to rats. On the contrary, 3-hydroxy-3-methylglutaryl-CoA reductase mRNA (9.9-fold) and Rd activity (16.7-fold) and phosphatidate phosphohydrolase activity (1.7-fold) increased, while plasma apo B-cholesterol (40%) and triglyceride (43%) levels decreased. As a part of a compensatory homeostatic response, we report for the first time that gemfibrozil administration to rats increased the hepatic sterol regulatory element binding protein-2 (SREBP-2) mRNA (2.9-fold) and mature protein (2.2-fold) levels. An early increase in the transcriptional activity of SREBP-2 elicited by gemfibrozil administration might be responsible for the observed changes in HMG-CoA reductase, phosphatidate phosphohydrolase, and SREBP-2 expression.

Current source density analysis of CNV during temporal gap paradigm

The present report studied the contingent negative variation during Gap and Non-Gap conditions using visual stimulation and manual responses. The reaction times during the Gap condition were facilitated compared with those of the Non-Gap condition. The contingent negative variation component was obtained during the preparatory period from electrodes placed at 58 scalp sites for both Gap and Non-Gap conditions. The comparison between both conditions: Gap and non-gap did not show statistically significant differences during the preparatory period. The topography of the voltage and current source density maps showed three different foci: (i) an early negativity centred in electrodes overlying the supplementary motor area and cingulate motor areas, (ii) an activation over the primary motor cortex contralateral to the finger movement, and (iii) a bilateral activation on posterior sites. All these results suggest that the facilitation induced by the warning stimuli occurs in neural circuits that would be recruited for the subsequent processing of the imperative stimulus. The facilitation of the reaction times during the gap condition with respect to non-gap condition must be justified by neural events occurring during the gap period.

Bezafibrate reduces mRNA levels of adipocyte markers and increases fatty acid oxidation in primary culture of adipocytes

The molecular mechanisms by which peroxisome proliferator-activated receptor (PPAR) activation by fibrates reduces fat deposition and improves insulin sensitivity are not completely understood. We report that exposure of a rat primary culture of adipocytes for 24 h to the PPAR activator bezafibrate increased the mRNA levels of crucial genes involved in peroxisomal and mitochondrial beta-oxidation. The mRNA levels of the peroxisomal beta-oxidation rate-limiting enzyme acyl-CoA oxidase and of the muscle-type carnitine palmitoyl transferase I (M-CPT-I), which determines the flux of mitochondrial beta-oxidation, increased by 1.6-fold (P < 0.02) and 4.5-fold (P = 0.001), respectively. These changes were accompanied by an increase in the transcript levels of the uncoupling protein-2 (UCP-2; 1.5-fold induction; P < 0.05) and UCP-3 (3.7-fold induction; P < 0.001), mitochondrial proteins that reduce ATP yield and may facilitate the oxidation of fatty acids. Furthermore, bezafibrate increased the mRNA levels of the fatty acid translocase (2-fold induction; P < 0.01), suggesting a higher fatty acid uptake into adipocytes. In agreement with these changes, bezafibrate caused a 1.9-fold induction (P < 0.02) in 9,10-[(3)H]palmitate oxidation. Moreover, bezafibrate reduced the mRNA expression of several adipocyte markers, including PPARgamma (30% reduction; P = 0.05), tumor necrosis factor-alpha (33% reduction; P < 0.05), and the ob gene (26% reduction). In contrast, adipocyte fatty acid binding protein mRNA levels increased (1.5-fold induction; P < 0.01), pointing to a mobilization of fatty acids to mitochondria and peroxisomes. The reduction of the adipocyte markers caused by bezafibrate was accompanied by an increase in the mRNA levels of the preadipocyte marker Pref-1 (1.6-fold induction; P < 0.01). Some of the changes observed in the primary culture of rat adipocytes also were studied in the epididymal white adipose tissue of bezafibrate-treated rats for 7 days. In vivo, M-CPT-I mRNA levels increased (4.5-fold induction; P = 0.001) in epididymal white adipose tissue of bezafibrate-treated rats. Similarly, fatty acid translocase (2.6-fold induction; P = 0.002) and Pref-1 (5.6-fold induction) mRNA levels increased, although differences in the latter were not significant because of huge individual variations. These results indicate that exposure of adipocytes to bezafibrate, independent of its hepatic effects, increases the degradation of fatty acids, reducing their availability to synthesize triglycerides. As a result, some degree of dedifferentiation of adipocytes to preadipocyte-like cells is achieved. These changes may be involved in the reduction in fat depots and in the improvement of insulin sensitivity observed after bezafibrate treatment.

Uncoupling protein-3 mRNA up-regulation in C2C12 myotubes after etomoxir treatment

Uncoupling proteins (UCPs) are mitochondrial membrane proton transporters that uncouple respiration from oxidative phosphorylation by dissipating the proton gradient across the membrane. Treatment of C2C12 myotubes for 24 h with 40 microM etomoxir, an irreversible inhibitor of carnitine palmitoyltransferase I (CPT-I), up-regulated uncoupling protein 3 (UCP-3) mRNA levels (2-fold induction), whereas UCP-2 mRNA levels were not modified. Etomoxir treatment also caused a 2.5-fold induction in M-CPT-I (muscle-type CPT-I) mRNA levels. In contrast, other well-known peroxisome proliferator-activated receptor alpha (PPAR alpha) target genes, such as acyl-CoA oxidase and medium-chain acyl-CoA dehydrogenase, were not affected, suggesting that this transcription factor was not involved in the effects of etomoxir. Since it has been reported that CPT-I inhibition by etomoxir leads to a further increase in ceramide synthesis, we test the possibility that ceramides were involved in the changes reported. Similarly to etomoxir, addition of 20 microM C(2)-ceramide to C2C12 myotubes for 3, 6 and 9 h resulted in increased UCP-3 and M-CPT-I mRNA levels. These results indicate that the effects on UCP-3 mRNA levels could be mediated by increased ceramide synthesis.

Co-composting of chestnut burr and leaf litter with solid poultry manure

A co-composting of chestnut burr and leaf litter mixed with solid poultry manure was assessed by comparison of several chemical, physicochemical and biological parameters. The final pH of the co-compost was 8.89 and the C/N ratio was 13. The germination index (GI) obtained using the co-compost varied with the seeds used. It was 155.35% for ryegrass seeds, 56.56% for wheat seeds and 100% for barley seeds. The co-compost was mature in 103 days from a biological point of view.