Analysis of body fluid mixtures by mtDNA sequencing: An inter-laboratory study of the GEP-ISFG working group

The mitochondrial DNA (mtDNA) working group of the GEP-ISFG (Spanish and Portuguese Group of the International Society for Forensic Genetics) carried out an inter-laboratory exercise consisting of the analysis of mtDNA sequencing patterns in mixed stains (saliva/semen and blood/semen). Mixtures were prepared with saliva or blood from a female donor and three different semen dilutions (pure, 1:10 and 1:20) in order to simulate forensic casework. All labs extracted the DNA by preferential lysis and amplified and sequenced the first mtDNA hypervariable region (HVS-I). Autosomal and Y-STR markers were also analysed in order to compare nuclear and mitochondrial results from the same DNA extracts. A mixed stain prepared using semen from a vasectomized individual was also analysed. The results were reasonably consistent among labs for the first fractions but not for the second ones, for which some laboratories reported contamination problems. In the first fractions, both the female and male haplotypes were generally detected in those samples prepared with undiluted semen. In contrast, most of the mixtures prepared with diluted semen only yielded the female haplotype, suggesting that the mtDNA copy number per cell is smaller in semen than in saliva or blood. Although the detection level of the male component decreased in accordance with the degree of semen dilution, it was found that the loss of signal was not consistently uniform throughout each electropherogram. Moreover, differences between mixtures prepared from different donors and different body fluids were also observed. We conclude that the particular characteristics of each mixed stain can deeply influence the interpretation of the mtDNA evidence in forensic mixtures (leading in some cases to false exclusions). In this sense, the implementation of preliminary tests with the aim of identifying the fluids involved in the mixture is an essential tool. In addition, in order to prevent incorrect conclusions in the interpretation of electropherograms we strongly recommend: (i) the use of additional sequencing primers to confirm the sequencing results and (ii) interpreting the results to the light of the phylogenetic perspective.

Characterization by Fourier Transform Infrared Spectroscopy (FT-IR) and 2D IR Correlation Spectroscopy of PAMAM Dendrimer

FT-IR and 2D correlation spectroscopy were employed to study the microstructural changes occurring during phase transitions of a liquid crystal poly(amidoamine) codendrimer (PAMAM (L1)16(L2)16) generation 3, functionalized on the terminal groups by one-chain promesogenic calamitic units (4-(4'-decyloxybenzoyloxy)salicylaldehyde (L1)) and two-chain promesogenic calamitic units (4-(3',4'-didecyloxybenzoyloxy)salicylaldehyde (L2)). Spectral modifications associated with molecular conformation rearrangements allowing for molecular shape change on going from a liquid-crystalline organization to another were found. The transition temperatures were calculated, and they are in good agreement with the DSC data. Spectral analysis gives evidence of the LC phase transitions and to an additional transition associated with the existence of conformers. Various types of hydrogen bonding have been established.

How does glutamine synthetase activity determine plant tolerance to ammonium?

The wide range of plant responses to ammonium nutrition can be used to study the way ammonium interferes with plant metabolism and to assess some characteristics related with ammonium tolerance by plants. In this work we investigated the hypothesis of plant tolerance to ammonium being related with the plants' capacity to maintain high levels of inorganic nitrogen assimilation in the roots. Plants of several species (Spinacia oleracea L., Lycopersicon esculentum L., Lactuca sativa L., Pisum sativum L. and Lupinus albus L.) were grown in the presence of distinct concentrations (0.5, 1.5, 3 and 6 mM) of nitrate and ammonium. The relative contributions of the activity of the key enzymes glutamine synthetase (GS; under light and dark conditions) and glutamate dehydrogenase (GDH) were determined. The main plant organs of nitrogen assimilation (root or shoot) to plant tolerance to ammonium were assessed. The results show that only plants that are able to maintain high levels of GS activity in the dark (either in leaves or in roots) and high root GDH activities accumulate equal amounts of biomass independently of the nitrogen source available to the root medium and thus are ammonium tolerant. Plant species with high GS activities in the dark coincide with those displaying a high capacity for nitrogen metabolism in the roots. Therefore, the main location of nitrogen metabolism (shoots or roots) and the levels of GS activity in the dark are an important strategy for plant ammonium tolerance. The relative contribution of each of these parameters to species tolerance to ammonium is assessed. The efficient sequestration of ammonium in roots, presumably in the vacuoles, is considered as an additional mechanism contributing to plant tolerance to ammonium nutrition.

[Middle molecules removal. Beyond beta2-microglobulin]

The uremic toxin removal capacity mainly depends on dialyzer and hemodialysis modes. The low-flux hemodialysis only removes solutes having molecular weights less than 5.000 Da. High-flux hemodyalisis represents a form of low-volume hemodiafiltration because of the internal filtration and back-filtration that can take place within a dialyzer. Hemodiafiltration with large volumes of replacement fluid seems to be the best technique for removing all small, medium-sized and large molecules. The objective of our study was to evaluate the large molecules removal bigger than beta2-microglobuline on high flux haemodialysis and on-line hemodiafiltration with postdilutional infusion, in patients with three times a week dialysis and on short daily dialysis. We studied 24 patients, 15 males and 9 females stable on haemodialysis programme, twelve on standard four to five hours three times a week dialysis and twelve on 2 to 2 1/2 hours six times a week dialysis. All patients were dialysed with Fresenius 4008 monitor, three sessions on high flux haemodialysis (HD) and three sessions on on-line hemodiafiltration (OL-HDF). Two sessions with each filter were performed (polisulfone HF80, polyethersulfone Arylane H9 and new polisulfone APS 900). Pre and postdialysis concentrations of urea, creatinine, (beta2-microglobulin (beta2-m), myoglobin, prolactin and alpha1 microglobulin (alpha1-m) were measured. There was no difference in urea and creatinine small molecules removal. beta2m removal was 68% on HD and 81% on OL-HDF. Myoglobin and prolactin present a similar removal pattern, a higher removal with new filters (60% with Arylane and 59% with APS) in comparison with clasical polisulfone (22% with HF80). The mean alpha1-m reduction rate on HD was 6% and on OL-HDF 22%. OL-HDF with APS 900 filter was the most remove technique (35.4%), significatively higher than the other modes and filters. We can conclude that the new filters generation reach a better uremic toxins removal, specially in large molecules higher than beta2-m and on HD modality.

Gastric and intestinal differentiation in Barrett's metaplasia and associated adenocarcinoma

Intestinal metaplasia is a prerequisite criterion for the diagnosis of Barrett's metaplasia and the sole columnar esophageal lining associated with malignancy. It is recognized by the presence of goblet cells, but columnar non-goblet elements, producing gastric or intestinal proteins, are the prevalent cell population. The cellular heterogeneity of Barrett's metaplasia is well documented but the relationship between the distinct cell subtypes and neoplasia is unclear. Our aim was to clarify the relationship between the different metaplastic populations and malignancy in order to investigate putative markers for risk stratification of Barrett's patients. We studied 46 columnar-lined esophageal segments, 15 with associated adenocarcinoma. The presence of the gastric, MUC5AC and MUC6, and the intestinal, MUC2, proteins was evaluated in metaplastic (columnar and goblet) and neoplastic cells. In neoplasia MUC5AC and MUC6 were detected in 100% and 86.6% of the cases, respectively. In metaplasia there were no differences in MUC5AC and MUC6 immunoreactivity, between cases with and without associated neoplasia, except for goblet elements producing MUC6 that were exclusive of metaplasia adjacent to adenocarcinoma (P < 0.05). MUC2 was present in 86.6% of the neoplasia. In metaplasia it was restricted to Barrett's cases and was more frequent in areas with intestinal metaplasia. Columnar-lined esophagus without intestinal metaplasia did not express MUC2. Our study suggests a relationship between the metaplastic population with gastric phenotype and malignancy, and points to the involvement of columnar as well as goblet elements in tumorigenesis. The association between goblet cells aberrantly producing MUC6 and the presence of neoplasia suggests they may be useful for risk stratification.

NMR relaxation study of molecular dynamics in columnar and smectic phases of a PAMAM liquid-crystalline co-dendrimer

We present the first results obtained by proton ((1)H) nuclear magnetic relaxation studies of molecular dynamics in a supermolecular liquid-crystal dendrimer exhibiting columnar rectangular and smectic-A phases. The (1)H spin-lattice relaxation time (T(1)) dispersions are interpreted using two relaxation mechanisms associated with collective motions and local molecular reorientations of the dendritic segments in the low- and high-frequency ranges, respectively. The T(1) values show a drop around 2.3 MHz that is attributed to a contribution coming from cross-relaxation between (1)H and nitrogen nuclear spins. In the high-frequency range the motions appear to be of similar nature in both mesophases and are ascribed to reorientations of dendritic segments (belonging to the core and/or to the mesogenic units) characterized by two correlation times. Notable differences in the dynamics between the columnar and layered phases are observed in the low-frequency range. Depending on the mesophase they are discussed in terms of elastic deformations of the columns and layer undulations. In this study we find that the dendritic core influences the dynamics of the mesogenic units both for local and collective motions. These results can be understood in terms of spatial constraints imposed by the dendritic architecture and by the supermolecular arrangement in the mesophases.

Inactivation of Staphylococcus aureus and Salmonella enteritidis in tryptic soy broth and caviar samples by high pressure processing

We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 10(8)-10(9) colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar.

Deuterium NMR investigation of the biaxial nematic phase in an organosiloxane tetrapode

Deuterium NMR is used to examine the molecular order exhibited by an organosiloxane tetrapode giving the first experimental evidence, using a bulk sample, for the existence of a biaxial nematic phase in this type of compounds. The temperature dependence of the averaged quadrupolar coupling constant and asymmetry parameter was determined in the compound's nematic phase. Two distinct regimes could be identified, one with a vanishing asymmetry parameter corresponding to a uniaxial nematic phase and another with a significant temperature dependent asymmetry parameter, corresponding to a biaxial nematic phase. The high values obtained for the asymmetry parameter at the lower end of the nematic range are well above experimental error and constitute a definite proof of the biaxial nature of the nematic phase exhibited by the studied compound for those temperatures.

Serum activity/concentration profiles of a sustained-released formulation of sulphathiazole-trimethoprim (2.5:1) in calves

Thirty-six two-week-old healthy Holstein-Friesian calves weighing between 52 and 58 kg were divided at random into three groups of 12; group A calves were given a single oral bolus containing 2.5 g sulphathiazole and 1 g trimethoprim in a sustained-release formulation; group B received the same doses of the drugs but the trimethoprim was not in a sustained-release formulation; group C received a bolus containing 2.5 g sulphathiazole and 0.5 g conventional trimethoprim. Blood samples were collected at intervals for two days, the serum was separated and the composite antibacterial activity profiles of the mixture were analysed by an agar-diffusion microbiological method. The mean maximum activities in the serum of the three groups were 23.4 microg/ml in group A, 9.25 microg/ml in group B and 8.01 microg/ml in group C. The mean areas under the curves of the serum activity time curves were 838 microg/ml/hour in group A, 216 microg/ml/hour in group B and 182 microg/ml/hour in group C.

ACTH modulates ERK phosphorylation in the adrenal gland in a time-dependent manner

ACTH is known to act through the activation of cAMP/PKA in adrenocortical cells, but it has been suggested that it could also act via other pathways such as the ERK 1/2 cascade. To determine the effects of ACTH administration at sequential time points on the activation of ERKs 1/2, groups of rats (n = 6/group) were subjected to i.p. injections of either ACTH (Synacthen Depot-0.2 mg/Kg), or saline (Ct). The animals were sacrificed and the adrenal glands collected at different timings after ACTH injection (2 h, 18 h and 24 h). Two additional groups were injected daily until sacrifice (3 days and 15 days). Blood was collected for analysis and the adrenals were used for immunohistochemistry or Western Blot (WB) analysis. Immunoreactivity was scored by counting the mean number of zonae fasciculata (ZF) and reticularis (ZR) positive cells/section (mean +/- SEM). Adrenal weight was increased by ACTH in comparison with Ct. Corticosterone levels, as expected, were higher in ACTH treated animals than in Ct. The number of pERK positive cells increased in a time-dependent manner until 3d, and declined although not significantly in the 15 days animals (Control--48.13 +/- 9.0; ACTH 2 h--125.93 +/- 14.5; ACTH 18 h-139.46 +/- 10.0; ACTH 24 h--185.28 +/- 13.3; ACTH 3 days--198.47 +/- 18.6; ACTH 15 days--158.58 +/- 15.1). Comparable results were obtained with WB analysis. Our data shows that ACTH induces the activation of the MAPK/ERKs 1/2 cascade, especially in the ZF, consistent with this zone being more responsive to ACTH.

Enterocytic columnar non-goblet cells of Barrett's esophagus--an immunohistochemical demonstration of association with malignant evolution

Barrett's epithelium (BE), the esophageal columnar-lining with intestinal differentiation, is a premalignant condition predisposing to adenocarcinoma. Columnar cells are the prevalent element of BE, but the hallmark of intestinal differentiation is the goblet population that defines the specialised columnar epithelium (SCE). We have demonstrated that columnar cells adjacent to Barrett's adenocarcinoma (BA) exhibit enterocytic features in areas with and without SCE. Nevertheless, the relationship between malignancy and the presence of these elements is not established. To investigate whether intestinal differentiated cells, other than goblet cells, are associated to neoplasia we compared the prevalence of enterocytic features in columnar elements with and without associated BA through the use of sucrase-isomaltase (SI) immunoreactivity in 31 columnar esophageal segments (CLES) and 12 BA. In metaplasia, SI was only expressed at the columnar cells. Apical staining was exclusive of CLES with SCE. SI was present at the cytoplasm in 22.2% of CLES without SCE. Apical SI occurred in BE with and without carcinoma, similarly in areas with and without SCE (p = 0.11 and p = 0.50, respectively). In areas with SCE, columnar cells with apical SI were more frequent in cases of BE adjacent to carcinoma than in cases without neoplasia but the difference did not reach significance (p = 0.053). In areas without SCE, apical SI was significantly (p = 0.01) more frequent in cases with carcinoma. Apical SI was equally found in neoplastic as in metaplastic areas, with and without SCE, (p = 0.07 and p = 0.40, respectively). In conclusion this study on the frequency of SI on CLES with and without neoplasia demonstrated that additionally to SCE, metaplastic enterocytic cells are also associated with malignancy. It also confirmed that the presence of intestinal features are underestimated if only goblet elements are used for its identification, reinforcing the utility of the immunohistochemical recognition of enterocytic characteristics for establishing the diagnosis of BE.

Occurrence of Kudoa sp. (Myxozoa) in Trachurus trachurus L. (osteichthyes) in Portugal

Specimens of Trachurus trachurus L., obtained monthly in a fish market of Oporto from October 1998 to August 1999, were examined for the presence of Kudoa in the muscle. Kudoa sp. spores were found in 84.7% of the specimens (n = 209). The prevalence was not significantly different between seasons and was not related to the host's length. The infection does not seem to have negative effects on the fish quality once no macroscopic pseudocysts or myoliquefaction were detected.

Recurrent columnar-lined esophageal segments--study of the phenotypic characteristics using intestinal markers

Barrett's metaplasia is recognized by specialized columnar epithelium on the distal esophagus. The events involved in the transformation from squamous to Barrett's epithelium remain unclear. The present study describes the characteristics observed during the recurrence of four cases of columnar-lined esophagus. Red velvet, gastric-like, esophageal mucosa was observed to develop above the anastomosis during follow-up of four patients submitted to surgery for esophageal and junctional adenocarcinoma. The areas of recurrence were associated with reflux symptoms and inflammation, with ulceration in two cases. Biopsies from the upper gastrointestinal endoscopies were examined histologically using periodic acid-Schiff/Alcian blue to detect acid mucins and a monoclonal antibody raised against the enterocytic enzyme sucrase-isomaltase. In all cases the recurrent columnar-lined segments displayed intestinal features recognized morphologically, histochemically, and/or immunohistochemically. There was no evidence of specialized columnar epithelium in three cases. The fourth patient developed specialized columnar epithelium during the tenth year of surveillance. The presence of AB-positive columnar cells was a frequent and early event. Columnar cells with unequivocal apical sucrase-isomaltase were observed only in association with specialized columnar epithelium. Four conclusions were reached: that the development of columnar-lined mucosa without specialized columnar epithelium may be the earliest event in Barrett's metaplasia; that histochemistry is a useful method of recognizing a population with cryptic intestinal features; that acid mucin secretion precedes the production of enterocytic enzymes by columnar cells; and that a cell population with enterocytic differentiation, as assessed by sucrase-isomaltase expression, is associated with the development of specialized columnar epithelium. These characteristics of Barrett's esophagus development are clinically relevant as they suggest that patients with columnar-lined esophagus without specialized columnar epithelium may acquire 'true' intestinal phenotype, justifying them being considered as high- risk patients.

Rectangular to hexagonal columnar phase transition exhibited by a biforked mesogen

We present the structural study of a biforked compound exhibiting a Colr-Colh phase transition. This study was performed by means of DSC, optical microscopy, X-ray diffraction, dilatometry and molecular modelling. The molecular packing within the two columnar mesophases of this compound is discussed. For the first time, it is shown that the clusters of adjacent molecules which form the elementary section of a column are tilted with respect to the columnar axis in the rectangular mesophase. From the whole set of experimental data, the number of molecules in a columnar section is found to be about 5 in the rectangular mesophase, and 4 in the hexagonal one. The transition between the two columnar mesophases is discussed with respect to its slow kinetics.

Multicentre surveillance of antimicrobial resistance in enterococci and staphylococci from Colombian hospitals, 2001-2002

Invasive isolates of staphylococci and enterococci were collected from 15 tertiary care centres in five Colombian cities from 2001 to 2002. A total of 597 isolates were available for analysis. Identification was confirmed by both automated methods and multiplex PCR assays in a central laboratory. Staphylococcus aureus and coagulase-negative staphylococci (CoNS) corresponded to 49.6% and 29.6% of isolates, respectively, and 20.8% were identified as enterococci. MICs of ampicillin, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, linezolid, oxacillin, rifampicin, teicoplanin, tetracycline, trimethoprim/sulfamethoxazole (SXT) and vancomycin were determined using an agar dilution method as appropriate. Screening for vancomycin-resistant S. aureus was also carried out on brain-heart infusion agar plates supplemented with vancomycin. The presence of mecA and van genes was investigated in methicillin-resistant staphylococci and glycopeptide-resistant enterococci (GRE), respectively. All staphylococci were susceptible to vancomycin, teicoplanin and linezolid. No VISA isolates were found. In S. aureus and CoNS, the lowest rates of resistance were found for SXT (7.4%) and chloramphenicol (10.7%), respectively. Resistance to oxacillin in S. aureus and CoNS was 52% and 73%, respectively. The mecA gene was detected in 97.5% of methicillin-resistant S. aureus isolates. In enterococci, resistance to glycopeptides was 9.7%: vanA (58.3%) and vanB (41.7%) genes were found. Pulsed-field gel electrophoresis indicated that the GRE isolates were closely related. Rates of resistance to ampicillin, ciprofloxacin, chloramphenicol, rifampicin and high levels of gentamicin and streptomycin were 9.7%, 27.4%, 8.9%, 43%, 17% and 28.2%, respectively. All enterococci were susceptible to linezolid.

Vanilloid receptor 1 expression in the rat urinary tract

Previous findings have shown that the capsaicin sensitivity of sensory fibres is due to the expression of a specific membrane protein, the vanilloid receptor type 1 (VR1). In the present work we studied the distribution, morphology and the neurochemical content of nerve fibres expressing this receptor in the rat urinary tract. Immunolabelling was performed against the VR1 and the positive fibres were examined by light and electron microscopy. Colocalisation of VR1 and substance P or calcitonin gene-related peptide immunoreactivities, and isolectin B4 binding, was evaluated under the confocal microscope. In addition, the effect of intravesical administration of resiniferatoxin, an ultra-potent vanilloid receptor agonist, in the receptor expression in the bladder was also studied. Numerous VR1-immunoreactive fibres were found in the mucosa and muscular layer of the entire urinary tract except the kidney. In the bladder, most fibres were also substance P- or calcitonin gene-related peptide-immunoreactive but did not bind isolectin B4. Under the electron microscope VR1 immunoreactivity was confined to unmyelinated axons and varicosities containing small clear and large dense-core synaptic vesicles. They occurred beneath or among epithelial cells or closely apposed to smooth muscle cells. Intravesical resiniferatoxin decreased VR1 immunoreactivity transiently. These data indicate that primary sensory fibres expressing VR1 are extremely abundant in the rat urinary tract and that, in contrast to the skin, they belong almost exclusively to the peptide-containing sub-population of primary afferents. As capsaicin-sensitive bladder afferents are involved in nociception and reflex micturition control, the numerous free terminal nerve endings expressing VR1 in the mucosa seem more adequate to accomplish the former function. However, the close apposition between VR1-expressing fibres and smooth muscle cells suggests that they may also encode the tonus of the muscular layer.

Myoarchitecture and vasculature of the heart ventricle in some freshwater teleosts

The morphological characteristics of the ventricular myocardium and of coronary vascularization were studied in three freshwater teleost species, Piaractus mesopotamicus, Colossoma macropomum and Clarias gariepinus (African catfish), by correlating their ventricular shapes and swimming habits. In Piaractus mesopotamicus and Colossoma macropomum, species with highly active swimming habits, the cardiac ventricle showed a pyramidal shape and a richly vascularized myocardium consisting of an outer compact layer and inner spongy layer. In Clarias gariepinus, a less active species, we observed a saccular ventricle with a mixed myocardium and coronary arteries, in contrast to the ventricular structure of other species described in the literature.