Burkholderia cenocepacia phenotypic clonal variation during a 3.5-year colonization in the lungs of a cystic fibrosis patient

Chronic lung infection is the major cause of morbidity and premature mortality in cystic fibrosis (CF) patients. Bacteria of the Burkholderia cepacia complex are the most threatening pathogens in CF, and a better understanding of how these bacteria adapt to the CF airway environment and resist the host defense mechanisms and therapeutically administered antibiotics is crucial. To provide clues to the adaptive strategies adopted by Burkholderia cenocepacia during long-term colonization, we carried out a phenotypic assessment of 11 clonal variants obtained at the major Portuguese CF Center in Lisbon from sputa of the same CF patient during 3.5 years of colonization of the lungs, until the patient's death with cepacia syndrome. Phenotypic characterization included susceptibility assays against different classes of antimicrobials and characterization of cell motility, cell hydrophobicity and zeta potential, colony and cell morphology, fatty acid composition, growth under iron limitation/load conditions, exopolysaccharide production, and size of the biofilms formed. The results suggest the occurrence of clonal expansion during long-term colonization. For a number of the characteristics tested, no isolation time-dependent consistent alteration pattern could be identified. However, the values for antimicrobial susceptibility and swarming motility for the first B. cenocepacia isolate, thought to have initiated the infection, were consistently above those for the clonal variants obtained during the course of infection, and the opposite was found for the zeta potential. The adaptive strategy for long-term colonization, described here for the first time, involved the alteration of membrane fatty acid composition, in particular a reduction of the degree of fatty acid saturation, in the B. cenocepacia variants retrieved, along with the deterioration of pulmonary function and severe oxygen limitation.     

Investigation of Cyprinid herpesvirus-3 genetic diversity by a multi-locus variable number of tandem repeats analysis

Cyprinid herpesvirus-3 (CyHV-3), or koi herpesvirus (KHV), is responsible for high mortalities in aquaculture of both common carp (Cyprinus carpio carpio) and koi carp (Cyprinus carpio koi) worldwide. The complete genomes of three CyHV-3 isolates showed more than 99% of DNA sequence identity, with the majority of differences located in short tandem repeats, also called VNTR (variable number of tandem repeats). By targeting these variations, eight loci were selected for genotyping CyHV-3 by multiple locus VNTR analysis (MLVA). CyHV-3 strains obtained after sequential in vivo infections exhibited identical MLVA profiles, whereas samples originating from a single isolate passaged 6 and 82 times in vitro exhibited mutations in two of the eight loci, suggesting a relatively slow genetic evolution rate of the VNTRs. The method was subsequently applied on 38 samples collected in Indonesia, France and the Netherlands. Globally, the isolates grouped in two main genetic clusters, each one divided in two subgroups including either CyHV-3-U/I or CyHV3-J. Interestingly, Indonesian strains were rather distant from CyHV-3-J isolate. The results of the present study indicate that these VNTR molecular markers are efficient in estimating the genetic diversity among CyHV-3 isolates and are therefore suitable for further molecular epidemiological studies.     

PAT1 induces cell death signal and SET mislocalization into the cytoplasm by increasing APP/APLP2 at the cell surface

The cleavage of amyloid precursor protein (APP) by caspases unmasks a domain extending from membrane to caspase cleavage site. This domain induces apoptosis in vitro and in vivo when overexpressed in neurons through the help of an internalization vector. In this model, we previously showed that SET rapidly binds to the internalized domain and is involved in downstream deleterious effects. Under these conditions SET mislocalizes from the nucleus to the cytoplasm, as in Alzheimer's disease (AD). In this report using the same model, we show that PAT1 attaches to the internalized domain earlier than SET and that this binding causes an increase in the levels of APP and APLP2 at the cell surface. Down regulation experiments of PAT1 and of APP and APLP2 show that the increase of the levels of APP and APLP2 at the cell surface triggers the cell death signal and SET mislocalization into the cytoplasm. In the context of AD these data suggest that mislocalization of SET into the cytoplasm may occur downstream of first cell death signal events involving PAT1 protein.     

Long-term assessment of the Ross procedure in adults: Clinical and echocardiographic follow-up at 20 years

IntroductionThe Ross procedure is an alternative to standard aortic valve (AV) replacement in young and middle-aged patients. However, durability and incidence of reoperation remain a concern for most cardiac surgeons. Our aim was to assess very long-term clinical and echocardiographic outcomes of the Ross procedure.MethodsWe conducted a single-center retrospective analysis of 56 consecutive adult patients who underwent the Ross procedure. Mean age at surgery was 44±12 years (range, 16-65 years) and 55% were male. Clinical endpoints included overall mortality and the need for valve reoperation due to graft failure. The echocardiographic endpoint was the presence of any graft deterioration. Median clinical follow-up was 20 years (1120 patient/years).ResultsIndications for surgery were dominant aortic stenosis in 50% and isolated aortic regurgitation in 21%. Concomitant mitral valve repair was performed in 21% and a subcoronary technique was most commonly used (86%). Overall long-term survival was 91%, 80% and 77% at 15, 20 and 24 years, respectively. The survival rate was similar to the age- and gender-matched general population (p=0.44). During the follow-up period, freedom from graft reoperation was 80%. Eleven patients (31%) developed moderate AV regurgitation, three (8.6%) developed moderate pulmonary regurgitation and one (2.9%) presented moderate pulmonary stenosis.ConclusionThe Ross procedure, mostly using a subcoronary approach, proved to have good clinical and hemodynamic results, with low reoperation rates in long-term follow-up. Moderate autograft regurgitation was a frequent finding but had no significant clinical impact.     

Use of ELISA employing homologous and heterologous antigens for the detection of IgG and subclasses (IgG1 and IgG2) in the diagnosis of canine visceral leishmaniasis

Indirect immunofluorescence is the method recommended for the diagnosis of visceral leishmanisis in dogs, however, the accuracy of this technique is low and its use on a large scale is limited. Since ELISA does not present these limitations, this technique might be an option for the detection of IgG or specific IgG1 and IgG2 subclasses. Canine ehrlichiosis is an important differential diagnosis of American Visceral Leishmaniasis (AVL). The present study compared ELISA using Leishmania chagasi and Leishmania braziliensis antigen for the detection of anti-Leishmania IgG and subclasses in serum samples from 37 dogs naturally infected with L. chagasi (AVL) and in samples from four dogs co-infected with L. braziliensis and L. chagasi (CI). The occurrence of cross-reactivity was investigated in control serum samples of 17 healthy dogs (HC) and 35 infected with Ehrlichia canis (EC). The mean optical density obtained for the detection of IgG was significantly higher when L. chagasi antigen was used, and was also higher in subgroup VLs (symptomatic) compared to subgroup Vla (asymptomatic). The correlation between IgG and IgG1 was low. The present results suggest that IgG ELISA using homologous antigen yields the best results, permitting the diagnosis of asymptomatic L. chagasi infection and the discrimination between cases of AVL and ehrlichiosis in dogs.     

Reorganization of mossy fiber synapses in male and female hypothyroid rats: A stereological study

Thyroid hormone deficiency has been reported to interfere with synaptogenesis, particularly in those regions of the brain where the neurons display a late and protracted histogenesis, although the extent of the synaptic alterations remains unknown. To provide detailed quantitative data on the effects of hypothyroidism upon synapses, a link of the hippocampal circuitry was selected: the contact between mossy fibers and dendritic excrescences of CA3 pyramidal cells (MF-CA3 synapses). Groups of six male and six female rats aged 30 and 180 days were analyzed separately after being treated as follows: (1) hypothyroid from day 0 until day 30 (30 day old hypothyroid group); (2) hypothyroid from day 0 until day 180 (180 day old hypothyroid group); (3) hypothyroid until day 30 and thenceforth maintained euthyroid (recovery group); and (4) and (5) 30 and 180 day old control groups, respectively. Timm staining, Golgi impregnation, and electron microscopy were employed to estimate the volume of the mossy fiber system, the number and size of mossy fiber boutons, and the number and related features of MF-CA3 synapses. The volume of the mossy fiber system and the number of synaptic boutons were reduced in all experimental groups. The total number of synapses was decreased in 30 day old hypothyroid rats, but did not differ among 180 day old animals. Postsynaptic densities were shorter in hypothyroid and recovery groups than in controls, although the reduction was not as marked in recovery rats as it was in hypothyroid animals. Structural alterations were noted in the pre- and postsynaptic compartments of MF-CA3 synapses of both 180 day old hypothyroid and recovery rats. These changes can be regarded as mechanisms of reorganization as they underlie the compensation for the hypothyroid-induced numerical reduction of synapses observed in 30 day old animals and enable a complete catch-up of their total number. However, synaptic reorganization was not fully achieved, as revealed by the reduction in the size of the synaptic sites in hypothyroid and recovery animals. Finally, we demonstrate that hypothyroidism did not interfere with the sex-related differences of MF--CA3 synapses described in normal rats. © 1993 Wiley-Liss, Inc.     

The methylenetetrahydrofolate reductase (MTHFR) 677C-->T mutation and cardiovascular risk--A case of ischemic stroke and acute myocardial infarction.

The authors report the case of a 39-year-old male patient who had an ischemic stroke (complete infarction of right anterior cerebral circulation) and an acute myocardial infarction during the same year. Molecular study revealed he was homozygous for the 677C-->T mutation in the gene coding for methylenetetrahydrofolate reductase, a key enzyme of folate metabolism; deficiency of this enzyme is associated with increased cardiovascular risk and neurological lesions. Some considerations are put forward about hyperhomocysteinemia and the MTHFR 677C-->T mutation as cardiovascular risk factors.     

Some aspects of sensory properties of food that relate to food habits and associated problems of elderly consumers

A questionnaire was developed and administered to 30 elderly consumers to explore perceptions about sensory properties of food that relate to food habits and food-related problems. Fifty percent of the survey sample believed that their food habits had changed considerably in the past 10 years, and 47% believed that health problems influenced their food selection. Few reported changes in food preparation because of mastication problems. Approximately half believed that foods smelled and tasted as good to them now as foods did when the consumers were young. Sensory properties of food were significantly (p less than or equal to .05) more important than several other factors in making purchase decisions for food preparation in three specific social contexts.     

Human immunodeficiency virus infection and systolic myocardial performance

Cardiac dysfunction in HIV-infected patients is being increasingly recognized. The present echocardiographic and Doppler study was undertaken to evaluate left ventricular (LV) systolic performance during the different stages of the disease. Twenty-nine anti-HIV (positive (+) ambulatory patients (19 with AIDS and 10 with asymptomatic HIV infection) without cardiac symptoms were evaluated by two-dimensional and M-mode echocardiography. Four groups were identified: group A, 10 patients (9 without AIDS) with a normal echocardiogram; group B, 6 patients with LV dilatation but normal LV function; group C, 9 patients with abnormal regional contractility but normal global function; group D, 4 patients with dilated cardiomyopathy (DC). Doppler study of the aortic systolic flow was performed in the four groups and in a normal control group. Doppler parameters—peak aortic velocity, ejection time, and flow velocity integral—were similar in controls and in groups A and B. Groups C and D (with abnormal contractility by echocardiography) had lower values for all Doppler parameters and were significantly different from controls and from groups A and B. Patients with dilated cardiomyopathy (group D) had the lowest values for all Doppler data, consistent with their low systolic performance. This group also had the lowest CD4+ lymphocyte counts and the longest mean probable time of HIV infection (6.5 years), being significantly different from group A patients, who presented a mean probable time of infection of 2.7 years and higher CD4+ counts. The results confirm that myocardial dysfunction affecting HIV-infected patients is more common in the late stages of the disease. It is also shown that Doppler study of the aortic systolic flow relates more closely to global LV performance than conventional echocardiography alone, and better differentiates patients with normal from those with abnormal LV function.Presented at the 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993