[Acute hepatic failure and Hodgkin's disease]

We present the clinical outcome and imaging micro and macroscopic of a patient who died of e liver acute failure. Hodgkin disease with massive infiltration was found at necropsy. We offer a review of the liver complaint in this particular disease.

[Bronchial embolization in the treatment of hemoptysis]

The aim of this retrospective study was to evaluate the efficacy of bronchial artery embolization to treat hemoptysis. Eight hundred sixty-five patients were admitted to our hospital with hemoptysis during the study period. Bronchial arteriographs were obtained for 48, who suffered life-threatening hemoptysis refractory to medical treatment. The likely origin of bleeding was identified in 37: embolization was performed with particles measuring 250 to 1000 micra in size (Contour Emboli, Interventional Therapeutic Corporation, South San Francisco, California, USA) in 35 and with hemostatic collagen sponges in 2. The most common causes of hemoptysis were bronchiectasis (40%), pulmonary tuberculosis (33%), pulmonary aspergilloma (8%) and malignant neoplasm (8%), chronic bronchitis (6%); 4% of the cases were idiopathic. Immediate technical success was achieved in 34 patients (92%) as defined by the absence of hemorrhage for at least 24 hours. All embolized patients were followed until the first recurrence of bleeding or until discharge. Recurrence of hemoptysis (in the first month) was early in 5 patients (13.5%) and late (2 to 96 months) in 9 (24%). The severity of the initial and later episodes of hemoptysis was similar in all early recurrences and most late recurrences. A second embolization was performed six times, and medical and/or surgical treatment was given in all other cases. No significant complications attributable to the technique were observed. The results show that bronchial embolization is valid for the immediate control of life-threatening hemoptysis and has a low rate of severe complication; recurrence is relatively common.

The Pur10 protein encoded in the gene cluster for puromycin biosynthesis of Streptomyces alboniger is an NAD-dependent ATP dehydrogenase

The pur10 gene of the puromycin (pur) cluster of Streptomyces alboniger is essential for the biosynthesis of this antibiotic. Highly purified Pur10 protein, obtained in Escherichia coli as a recombinant protein fused to a histidine tail, had an NAD-dependent ATP dehydrogenase activity. The Km and Vmax values for ATP were 0.49 mM and 14.5 nmol/min and for NAD 0.53 mM and 15.2 nmol/min, respectively. The ATP-derived product of the reaction apparently decomposed producing a triphosphorylated compound plus an adenine derivative. These and previous results suggested that Pur10 carries out the first step of the puromycin biosynthetic pathway, namely, conversion of ATP into 3'-keto-3'-deoxyATP.

Determination of some aromatic amines in finger-paints for children's use by supercritical fluid extraction combined with gas chromatography

A test method based on supercritical fluid extraction (SFE) and gas chromatography has been developed for some aromatic amines, such as 4-chloro-o-toluidine, beta-naphthylamine and 4-aminobiphenyl. A two-level factor design was used as the optimization procedure. Four main variables were considered: CO2 pressure, extraction temperature, static extraction time and volume of modifier (methanol). Results obtained for 4-chloro-o-toluidine, indicated that the volume of modifier was the variable with the most important influence on extraction, CO2 pressure had a negative effect and temperature and time were less significant. For the other amines, static time was the most important variable in both cases, followed by CO2 pressure and volume of modifier, with no influence of temperature. SFE was compared with Soxhlet extraction, and was found to give higher recoveries in all cases. Other commercial finger-paints were tested for the presence of aromatic amines.

StgR, a new Streptomyces alboniger member of the LysR family of transcriptional regulators

A 3240-bp DNA fragment, located next to the puromycin biosynthetic gene cluster of Streptomyces alboniger, contains three complete ORFs in the order: stgA, stgU and stgR. The transcriptional orientation of stgA is opposite to that of stgU and stgR. Each gene is expressed from its own promoter, although stgU and stgR can be cotranscribed. The deduced amino acid sequences of their products present similarities to a variety of pyridoxal-phosphate-dependent aspartate aminotransferases (StgA), several proteins of unknown function (StgU), and the LysR-type of transcriptional regulators (StgR). In a delta stgR null mutant of S. alboniger, transcription of stgA and stgU is increased with respect to that in the wild type. In addition, in vivo experiments with promoter-probe plasmids indicated that in the delta stgR mutant, stgA- or stgU-promoter-dependent expression of the reporter gene was up to three-fold higher than in the wild type. Taken together, these results indicate that StgR is a LysR-type transcriptional repressor of both stgA and stgU.

[Electromagnetic interference between automatic defibrillators and digital and analog cellular telephones]

BACKGROUND AND OBJECTIVES

Functional pacemaker interference by mobile telephones has been described with analogical systems and with possible greater influence, digital systems, including inhibition and inadequate pacing. The influence of both system has not been extensively studied in patients with implantable cardioverter defibrillators (ICD).

PATIENTS AND METHODS

We studied the influence of mobile phones, both digital and analogic network, on the performance of several models of defibrillators, in a standardised test set up designed to provide high sensitivity. The purpose of our study was to establish whether there are any influences on ICD functions, both in in vivo and in in vitro models. Several mobile phones, with different transmission powers, were moved towards the defibrillator and the electrode, under continuous documentation of defibrillator sensing and interrogation afterwards. The experimental model was performed with the aid of an arrhythmia simulator (Intersim) and demo-defibrillators. The tests were repeated both in and out of a solution of saline water with an impedance within normal human limits.

RESULTS

Partial loss of telemetry was found in 14 patients, 8 with analogical phones and 6 with digital phones. Fourteen patients showed alterations only on the surface electrocardiogram channel and five on the intracavitary channel. The same results were reproduced in the in vitro model. However, the in vitro test allowed us to simulate multiple ventricular arrhythmias, and demonstrate the normal sensing and functioning of the defibrillator during a "spontaneous" arrhythmia. After testing, we demonstrate that no real oversensing/undersensing was documented in any device. There was no evidence of ICD reprogramming or pacing inhibition. In particular, no inadequate therapies were delivered.

CONCLUSIONS

a) in our series, we have not demonstrated clinically significant electromagnetic interferences with mobile phones of digital or analogical networks: b) the in vitro model allowed us to conclude that even if a spontaneous arrhythmia appears, the function of the defibrillator is not altered; c) the use of mobile phones seems to be safe for defibrillator patients, and d) however, some basic rules, such as to maintain the phone at least 15 cm away from the defibrillator, are advised.

Nitrergic innervation of the cat liver

The aim of this work was to study the nitrergic innervation in the liver of the cat using immunocytochemical procedures. At the hepatic hilus, a rich plexus of neuronal nitric oxide synthase immunoreactive (nNOS-IR) nerve fibers and ganglia was detected around the interlobular branch of the bile duct. nNOS-IR nerve fibers were observed running with the components of the intralobular portal triads located close to the hepatic hilus, as well as with a few vessels and ducts of the deeper parenchyma. These latter fibers, beside others located in Glisson's capsule, occasionally showed short ramifications entering the parenchyma itself. The present results suggest that, in the cat liver, nNOS is involved in the autonomic control of hepatic blood flow, with a limited role in the regulation of hepatobiliary excretory activity and hepatocellular metabolic function.

Identification of cDNAS encoding plastid-targeted glutathione peroxidase

A cDNA was isolated from pea leaf RNA which encodes a phospholipid hydroperoxide glutathione peroxidase (PHGPX; E.C. 1.1.1.1.9). The N-terminal section of this PHGPX encodes a recognisable chloroplast transit peptide. Efficient import in vitro of the pre-PHGPX protein into the stroma of isolated pea chloroplasts confirmed that the PHGPX is a chloroplast-located enzyme. The pea PHGPX has highly conserved homologues in Arabidopsis, citrus and Nicotiana sylvestris and the authors suggest that these proteins are also localised in the chloroplast and not in the cytosol as previously supposed.

Expression of the Streptomyces alboniger pur cluster in Streptomyces lividans is dependent on the bldA-encoded tRNALeu

Streptomyces lividans 1326-9, a bldA+ strain, and its bldA39 mutant derivative J1725 were transformed with a cosmid containing the pur cluster, which determines the puromycin biosynthetic pathway from Streptomyces alboniger. bldA+ transformants produced puromycin in typical amounts, whereas bldA39 transformants did so at drastically decreased levels. Transformation of low producers with the wild-type bldA gene reverted this phenotype to normal production. These data, in addition to the presence of a TTA codon in the amino-terminal coding region of the pur10 and pur6 genes of the pur cluster, suggest that the puromycin biosynthetic pathway is translationally dependent on the bldA gene product, a tRNALeu.

Degradation of hemicellulosic and cellulosic polysaccharides in pickled green olives

Changes that take place in the hemicellulosic and cellulosic polysaccharide fractions of the cell wall of olives (Olea europaea pomiformis, Manzanilla variety) during "Spanish style" processing have been studied. A comparative study of the extraction of hemicellulosic polysaccharides with and without prior delignification showed that these compounds could be extracted without previous delignification of the cell wall material. The depectinated material was sequentially extracted with 1 M and 4 M potassium hydroxide. In the unprocessed fruit, the neutral polysaccharides of the 1 M potassium hydroxide-soluble fraction contained mainly xyloglucans with significant amounts of arabinans. In the 4 M potassium hydroxide-soluble fraction, xyloglucans were the most important polysaccharide. The apparent molecular weight of these polysaccharides was 40 to 250 kDa. In addition, hemicelluloses (xylans and xyloglucans), which it was not possible to isolate in the previous stages of fractionation, were also found to be closely linked to the cellulose fraction. The most important changes during processing were the decrease in the molecular weight of xyloglucans in the 4 M potassium hydroxide-soluble fraction and the substantial decrease in the cellulose fraction, which in quantitative terms was one of the largest decreases that took place in the components of the total cell wall polysaccharides.

BN 52021 (a platelet activating factor-receptor antagonist) decreases alveolar macrophage-mediated lung injury in experimental extrinsic allergic alveolitis

Several lines of research indirectly suggest that platelet activating factor (PAF) may intervene in the pathogenesis of extrinsic allergic alveolitis (EAA). The specific aim of our study was to evaluate the participation of PAF on macrophage activation during the acute phase of EAA in an experimental model of this disease developed in guinea pigs. Initially we measured the concentration of PAF in bronchoalvedar lavage fluid, blood and lung tissue. In a second phase we evaluate the participation of PAF on alveolar macrophage activation and parenchymal lung injury. The effect of PAF on parenchymal lung injury was evaluated by measuring several lung parenchymatous lesion indices (lung index, bronchoalvedar lavage fluid (BALF) lactic hydrogenase activity and BALF alkaline phosphatase activity) and parameters of systemic response to the challenge (acute phase reagents). We observed that induction of the experimental EAA gave rise to an increase in the concentration of PAF in blood and in lung tissue. The use of the PAF-receptor antagonist BN52021 decreases the release of lysosomal enzymes (beta-glucuronidase and tartrate-sensitive acid phosphatase) to the extracellular environment both in vivo and in vitro. Furthermore, antagonism of the PAF receptors notably decreases pulmonary parenchymatous lesion. These data suggest that lung lesions from acute EAA are partly mediated by local production of PAF.

Degradation of pectic polysaccharides in pickled green olives

The changes that occur in the pectic fractions in the cell wall of olives of the Manzanilla variety (Olea europaea pomiformis) during processing (initial treatment at high pH and subsequent lactic fermentation) have been researched. After studying various conditions for fractionating the pectic polysaccharides, the most adequate were chosen, involving sequential extraction with water, imidazole-hydrochloric acid buffer, sodium carbonate, 1 M potassium hydroxide, and 4 M potassium hydroxide. In the unprocessed fruit, the fractions studied consist mainly of high-molecular-weight acidic polysaccharides (70 to 250 kDa): homogalacturonans, rhamnogalacturonans, and branched arabinans. These were found in different proportions depending on the extraction agent used. At the same time, significant amounts of relatively low-molecular-weight (10 to 10.5 kDa) neutral branched arabinans were found in the water-soluble fraction. As a result of the processing, changes occurred in the proportions of the different groups of polysaccharides in accordance with changes in their solubility characteristics. These changes were reflected in the processed fruit by (i) and increase in the neutral branched arabinans in the water-soluble fraction due to the increased presence of such polysaccharides originally found in the carbonate and 4 M KOH-soluble fractions; (ii) an increase in homogalacturonans and rhamnogalacturonans, without significant changes in molecular weights, in the imidazole-soluble fraction as a result of the increased presence of corresponding polysaccharides originally found in the carbonate-soluble and water-soluble fractions; (iii) a substantial increase in uronic acids in the 1 M potassium hydroxide-soluble fraction, preferentially as low-molecular-weight polysaccharides; and (iv) a solubilization of arabinans in the 4 M potassium hydroxide-soluble fraction.

Expression of the Schwanniomyces occidentalis SWA2 amylase in Saccharomyces cerevisiae: role of N-glycosylation on activity, stability and secretion

The role of N-linked glycosylation on the biological activity of Schwanniomyces occidentalis SWA2 alpha-amylase, as expressed in Saccharomyces cerevisiae, was analysed by site-directed mutagenesis of the two potential N-glycosylation sites, Asn-134 and Asn-229. These residues were replaced by Ala or Gly individually or in various combinations and the effects on the activity, secretion and thermal stability of the enzyme were studied. Any Asn-229 substitution caused a drastic decrease in activity levels of the extracellular enzyme. In contrast, substitutions of Asn-134 had little or no effect. The use of antibodies showed that alpha-amylase was secreted in all the mutants tested, although those containing substitutions at Asn-229 seemed to have a lower rate of synthesis and/or higher degradation than the wild-type strain. alpha-Amylases with substitution at Asn-229 had a 2 kDa lower molecular mass than the wild-type protein, as did the wild-type protein itself after treatment with endoglycosidase F. These findings indicate that Asn-229 is the single glycosylated residue in SWA2. Thermostability analysis of both purified wild-type (T50=50 degrees C, where T50 is the temperature resulting in 50% loss of activity) and mutant enzymes indicated that removal of carbohydrate from the 229 position results in a decrease of approx. 3 degrees C in the T50 of the enzyme. The Gly-229 mutation does not change the apparent affinity of the enzyme for starch (Km) but decreases to 1/22 its apparent catalytic efficiency (kcat/Km). These results therefore indicate that glycosylation at the 229 position has an important role in the extracellular activity levels, kinetics and stability of the Sw. occidentalis SWA2 alpha-amylase in both its wild-type and mutant forms.

Temporal variation of allozyme frequencies in Aedes albifasciatus (Diptera: Culicidae) from Argentina

Aedes albifasciatus is a floodwater mosquito widely distributed in Argentina. It is important from economic and medical points of view. A 4-year survey of seasonal variation in allele frequencies in a population of this species was undertaken to determine possible changes in the genetic structure and their correlation with environmental conditions. Significant temporal variation was detected at most of the loci, but it did not follow a cyclic or seasonal pattern. Multivariate analysis of principal components showed a remarkable homogeneity of samples collected from December 1993 to April 1995 and a clear differentiation of the November 1991, March 1992, and November 1993 samples. This variation could be correlated with the magnitude of rainfall occurring in the area. Passive transport of larvae by water streams and river freshets produced by floods would have mixed larvae from breeding sites with different allele frequencies, causing the genetic differentiation observed.

Response to barium selenate supplementation in sheep kept at pasture in the Mediterranean area

This work evaluated the efficacy of barium selenate supplements in the prevention of disorders related to Se deficiency in sheep maintained at pasture in the Mediterranean area. Ewes on five farms were divided into two equal groups of 1,750 animals: a) the treated group and b) the control group. The animals of the treated group were injected subcutaneously, in the first third of gestation, with a barium selenate compound at a dose of 1 mg Se/kg. The ewes in the control group did not receive any supplement of Se and/or vitamin E. The two groups were managed under the same feeding and husbandry practices throughout the experiment. After lambing, blood glutathione peroxidase (GSHPx) and serum aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH) activities were measured in the lambs born to both group. Blood GSHPx activity was higher in the treated animals, with statistically significant differences due to the response to injection of barium selenate. Mean global serum activities of AST and CK tended to be higher in the control group, as a consequence of the protection given to the treated group by the supplement, but the differences were not statistically significant. This was possibly due to the absence of clinical cases of nutritional myodystrophy (NMD) in the animals of the control group. Therefore it can be stated that barium selenate supplementation can prevent Se deficiency in sheep herds maintained at pasture in this area.