Ventriculoperitoneal shunt as a primary neurosurgical procedure in newborn posthemorrhagic hydrocephalus: report of a series of 47 shunted patients

PURPOSE

Intraventricular hemorrhage is the most common cause of infantile acquired hydrocephalus. Our objective is to determine if the implantation of ventriculoperitoneal shunt in posthemorrhagic hydrocephalus as a primary and definitive neurosurgical treatment, with no previous temporary procedures, would decrease complication rates with good functional outcomes.

METHODS

Two hundred seventy-one patients with germinal matrix hemorrhage were diagnosed at the Carlos Haya Hospital between 2003 and 2010. Forty-seven patients underwent ventriculoperitoneal shunt after developing symptomatic hydrocephalus. The minimum weight required for shunt implantation was 1,500 g. We recorded complications related to the surgical procedure and analyzed functional state with a self-developed four-grade scale.

RESULTS

One hundred thirty-nine (51.3 %) patients with intraventricular hemorrhage developed ventricular dilatation, but only 47 patients (17.34 %) needed shunting. In seven cases, temporary neurosurgical procedures were performed, but in all of them, this was followed by ventriculoperitoneal shunt implantation. The infection rate was 4.25 %, and shunt obstruction rate was 4.25 %. More than 80 % of patients were classified as good or excellent functional state. Mean follow-up period was 38.75 months (SD, 27.09; range, 1-102 months).

CONCLUSIONS

Ventriculoperitoneal shunting as a primary neurosurgical treatment in posthemorrhagic hydrocephalus would decrease surgical morbidity with good functional outcome.

Clinical, metabolic and psychological outcomes and treatment costs of a prospective randomized trial based on different educational strategies to improve diabetes care (PRODIACOR)

AIM

To evaluate the effect of system interventions (formalized data collection and 100% coverage of medications and supplies) combined with physician and/or patient education on therapeutic indicators and costs in Type 2 diabetes.

METHODS

This was a randomized 2 × 2 design in public health, social security or private prepaid primary care clinics in Corrientes, Argentina. Thirty-six general practitioners and 468 adults with Type 2 diabetes participated. Patients of nine participating physicians were selected randomly and assigned to one of four structured group education programmes (117 patients each): control (group 1), physician education (group 2), patient education (group 3), and both physician education and patient education (group 4), with identical system interventions in all four groups. Outcome measures included HbA(1c), BMI, blood pressure, fasting glucose, lipid profile, drug consumption, resource use and patient well-being at baseline and every 6 months up to 42 months.

RESULTS

HbA(1c) decreased significantly from 4 mmol/mol to 10 mmol/mol by 42 months (P < 0.05); the largest and more consistent decrease was in the groups where patients and physicians were educated. Blood pressure and triglycerides decreased significantly in all groups; the largest changes were recorded in the combined education group. The World Health Organization-5 Lowe score showed significant improvements, without differences among groups. The lowest treatment cost was seen in the combined education group.

CONCLUSIONS

In a primary care setting, educational interventions combined with comprehensive care coverage resulted in long-term improvement in clinical, metabolic and psychological outcomes at the best cost-effectiveness ratio.

N-site de-methylation in pyrimidine bases as studied by low energy electrons and ab initio calculations

Electron transfer and dissociative electron attachment to 3-methyluracil (3meU) and 1-methylthymine (1meT) yielding anion formation have been investigated in atom-molecule collision and electron attachment experiments, respectively. The former has been studied in the collision energy range 14-100 eV whereas the latter in the 0-15 eV incident electron energy range. In the present studies, emphasis is given to the reaction channel resulting in the loss of the methyl group from the N-sites with the extra charge located on the pyrimidine ring. This particular reaction channel has neither been approached in the context of dissociative electron attachment nor in atom-molecule collisions yet. Quantum chemical calculations have been performed in order to provide some insight into the dissociation mechanism involved along the N-CH3 bond reaction coordinate. The calculations provide support to the threshold value derived from the electron transfer measurements, allowing for a better understanding of the role of the potassium cation as a stabilising agent in the collision complex. The present comparative study gives insight into the dynamics of the decaying transient anion and more precisely into the competition between dissociation and auto-detachment.

[Decrease in allogenic transfusions due to the spread of use of postoperative retransfusion systems in knee replacement surgery]

OBJECTIVES

Surgical teams have several tools in order to reduce the need for postoperative allogenic transfusion. Postoperative autotransfusion of unwashed shed blood has become common practice for total knee replacement surgery since 2006 in our hospital. This study was designed to evaluate if this practice has reduced allogenic blood transfusions.

MATERIAL AND METHODS

A retrospective study comparing two cohorts, group 2004 with patients operated on for total knee replacement during the year 2004, before the use of the retransfusion system, and group 2008, patients operated on in the year 2008, with regular use of the retransfusion system. Gender, preoperative and postoperative haemoglobin levels, total amount of calculated erythrocytes lost, reinfusion of shed blood and allogenic blood transfusion during hospital stay were recorded.

RESULTS

Both groups were similar as regards gender, preoperative and postoperative hemoglobin levels, and total amount of erythrocytes lost. The proportion of transfused patients was significantly lower in group 2008 versus group 2004 (20.18% versus 42.19%), with a relative risk of being transfused of 0.47 and a NNT of 4.54. P=.0017.

CONCLUSIONS

In our hospital the use of postoperative retransfusion systems has reduced the proportion of transfused patients during hospitalization for total knee replacement surgery, although this result cannot be generalized due to the lack of a fixed transfusion trigger.

Pathogenesis of scrapie in ARQ/ARQ sheep after subcutaneous infection: effect of lymphadenectomy and immune cell subset changes in relation to prion protein accumulation

It is well established that the infectious agent of scrapie can replicate in the lymphoreticular system (LRS). However, the effects of removal of LRS target tissues on the pathogenesis of the infection and the accumulation of disease-associated prion protein (PrP(d)) in LRS tissues on specific immune cell subsets are poorly understood aspects. To address these questions 16 ARQ/ARQ sheep were subcutaneously inoculated in the drainage area of the prefemoral lymph node with brain homogenate derived from Suffolk sheep naturally infected with scrapie. Fourteen sheep were then subjected to either early (14-17 days post-inoculation [dpi]) or late (175-201 dpi) lymphadenectomy and culled at preclinical or clinical stages of infection. Neither late nor even early lymphadenectomy prevented infection or had any effect on the accumulation of PrP(d) in the LRS or CNS suggesting a rapid organic dissemination of the infectious agent after inoculation. Lymph nodes from eight scrapie inoculated sheep selected on the basis of the amount of PrP(d) in their LRS tissues (negative, low or high) were examined for six different immune cell markers. The PrP(d) negative lymph nodes from two sheep with no evidence of scrapie infection showed lower numbers of cluster of determination (CD) 21 positive cells than PrP(d) positive nodes, irrespective of their location (hind leg or head). However, quantitative differences in the expression of this marker were not detected when comparing lymph nodes with low and high levels of PrP(d) accumulation, suggesting that proliferation of CD21 positive cells is related to scrapie infection, but not directly linked to the magnitude of PrP(d) accumulation. An additional observation of the study was that sheep that were methionin-threonine at codon 112 of the prion protein gene showed lower attack rates than methionine homozygotes (67% and 100%, respectively) and also generally lower levels of PrP(d) accumulation in the LRS and brain and increased survival times, suggesting an influence of such polymorphism in the susceptibility to scrapie.

Expression of TLR3, 4, 7 and 9 in cutaneous malignant melanoma: relationship with clinicopathological characteristics and prognosis

Toll-like receptors (TLRs) have achieved an extraordinary amount of interest in cancer research due to their role in tumor progression. The aim of this study was to investigate the expression and clinical relevance of TLR3, 4, 7 and 9 in cutaneous malignant melanoma (CMM). The expression levels of TLR3, 4, 7 and 9 were analyzed in tumors from 30 patients with CMM. The analysis was performed by immunohistochemistry, and the results were correlated with various clinicopathological findings and with relapse-free survival. Our results indicate that there was a wide variability in the immunostaining score values for each receptor. Positive staining for TLRs was generally found in tumor cells, especially for TLR4 and TLR9. Nevertheless, a significant percentage of tumors also showed TLR4 expression in mononuclear inflammatory cells (62.1 %) and in fibroblast-like cells (34.5 %). Our results showed no significant association between score values for each TLR and clinicopathological characteristics of patients. However, our results demonstrated that high TLR4 expression was significantly associated with a shortened relapse-free survival (p = 0.001). Therefore, TLR4 expression may be a new prognostic factor of unfavorable evolution in cutaneous malignant melanoma.

Ultrasound monitoring of the setting of calcium-based bone cements

In this study, the setting of calcium-sulphate (CS) and -phosphate (CP) based bone cements (BCs) was monitored by ultrasound. The objective was to link acoustic and material properties of ceramic-based BCs from the early stages of the cement curing process. The powder phase of the CS-cement consisted of CS hemihydrate; the CP-cement was a mixture of alpha-tricalcium phosphate, CS dihydrate and hydroxyapatite. For the CS-cement, the acoustic impedance z (c)(t), the speed of sound c (c)(t) and the density ρ(c)(t) were measured at the interval of liquid-to-powder ratios LPRs from 0.20 to 3.00 ml/g. For the CP-cement, the acoustic characteristics obtained were the z (c)(t) and the reflection coefficient R (p,c)(t), and the LPRs ranged from 0.30 to 0.40 ml/g. The resulting acoustic properties indicated that CP- and CS-cements exhibited distinctly different curing behaviour; while CS-cement expanded, CP-cement shrank with time.

Design and characterisation of new nanoparticulate polymer blends for drug delivery

The aim of the present work was the design of novel nanoparticle compositions based on poly(lactic acid/glycolic acid) (PLGA): poloxamer and PLGA: poloxamine blend matrices. For this purpose, we have applied a modified solvent diffusion technique that allows the preparation of the nanoparticles without the use of high energy sources. Nanoparticles have been prepared with different PLGA: poloxamer and PLGA: poloxamine ratios using PEO-derivatives with different molecular weights (Mw) and hydrophilia-lipophilia balance (HLB) values. Our results show that the physicochemical characteristics of the nanoparticles, such as size and zeta potential, are influenced by the type of PEO-derivative associated to the PLGA matrix. The 1H-NMR analysis of the different nanoparticle compositions showed that the extent of incorporation of the PEO-derivative depends strongly on its HLB and also on the nanoparticles preparation conditions. The capacity of these nanoparticles as drug delivery devices was evaluated using bovine insulin as a model drug. The insulin-encapsulation efficiency was shown to be dependent on the composition of the nanoparticles, those containing hydrophilic PEO-derivatives being the most effective in entrapping the drug molecules. The formation of the blend system displayed positive effects on the release characteristics of the nanoparticles. Nanoparticles exhibited a reduced initial burst and a nearly linear, constant release rate over a time period of two weeks.

The distribution of immune cells in the lungs of classical and atypical ovine pulmonary adenocarcinoma

Ovine pulmonary adenocarcinoma (OPA) is a contagious tumour caused by infection of sheep with Jaagsiekte sheep retrovirus. Two forms of OPA have been identified, classical and atypical, which can be distinguished clinically and pathologically. Most notably classical OPA is progressive until death, while atypical OPA remains subclinical. In the present study the local immune responses in the lungs of cases of atypical OPA were compared with those from classical cases by immunohistochemistry using a panel of mouse anti-sheep mAbs. Distinct differences in the distribution of immune cell subsets in the two forms of OPA were observed. In particular there was an intratumoural influx of T cell subsets and MHC Class II expression on the tumour cells in atypical OPA, neither of which was seen in classical OPA. It is possible that these differences may contribute, at least in part, to determining the progressive course of classical OPA compared with the subclinical nature of atypical OPA.

Neuropathological changes correlate temporally but not spatially with selected neuromodulatory responses in natural scrapie

AIM

Neuropathological changes classically associated with sheep scrapie do not always correlate with clinical disease. We aimed to determine if selected neuromodulatory responses were altered during the course of the infection as it has been described in Creutzfeldt-Jakob disease and experimental bovine spongiform encephalopathy.

METHODS

Hemi-brains from healthy sheep and natural scrapie cases at two stages of infection were examined for biochemical alterations related to the expression of type I metabotropic glutamatergic receptors (mGluR(1) ) and type I adenosine receptors I (A(1) R), and of selected downstream intermediate signalling targets. Immunohistochemistry for different scrapie-related neuropathological changes was performed in the contralateral hemi-brains.

RESULTS

PrP(d) deposition, spongiform change, astrocytosis and parvalbumin expression were significantly altered in brains from clinically affected sheep compared with preclinical cases and negative controls; the latter also showed significantly higher immunoreactivity for synaptophysin than clinical cases. Between clinically affected and healthy sheep, no differences were found in the protein levels of mGluR(1) , while phospholipase Cβ1 expression in terminally ill sheep was increased in some brain areas but decreased in others. Adenyl cyclase 1 and A(1) R levels were significantly lower in various brain areas of affected sheep. No abnormal biochemical expression levels of these markers were found in preclinically infected sheep.

CONCLUSIONS

These findings point towards an involvement of mGluR(1) and A(1) R downstream pathways in natural scrapie. While classical prion disease lesions and neuromodulatory responses converge in some affected regions, they do not do so in others suggesting that there are independent regulatory factors for distinct degenerative and neuroprotective responses.

Effectiveness and use of linezolid in hospitalisation wards

OBJECTIVE

To describe the use and effectiveness of linezolid as an alternative treatment for methicillin-resistant Staphylococcus aureus.

METHOD

Demographic, clinical and safety data were collected from hospitalised patients. The information sources were the clinical records and the pharmacy programme.

RESULTS

Thirty patients were treated with linezolid (median age 69.3, 63% male). The median duration of treatment was 8 days. The most prevalent indication was soft tissues and skin infections (46.7%). The indications were off-label in 40% of cases. Linezolid was used as a targeted therapy in 53%, especially for coagulase-negative Staphylococcus. Clinical healing occurred in 83.3%, and microbiological healing in 40%. Three patients (10%) experienced side effects from using linezolid.

CONCLUSION

The effectiveness and safety of linezolid is similar to that described in the trials. Its off-label use and the high number of empirical treatments mean that new strategies must be developed.

Immunophenotype of cells within cervine rectoanal mucosa-associated lymphoid tissue and mesenteric lymph nodes

Rectoanal mucosa-associated lymphoid tissue (RAMALT) is a part of the lymphoid system that can be sampled easily in live animals, especially ruminants. RAMALT biopsy is useful for the diagnosis of transmissible spongiform encephalopathies, including scrapie in sheep and goats and chronic wasting disease (CWD) in cervids. Diagnosis is reliant on detection of abnormal prion protein (PrP(d)), which is associated with lymphoid follicles. For enzyme linked immunosorbent assays (ELISAs) detecting PrP(d) it is necessary to ensure that lymphoid follicles are present in biopsy samples to avoid false-negative results. Monoclonal antibodies known to recognize specific immune cell subsets present in lymphoid tissues of sheep were tested for cross-reactivity with cervine RAMALT and mesenteric lymph nodes (MLNs) preserved in zinc salts fixative. The distribution of cells expressing CD3, CD4, CD79, CD21 and class II molecules of the major histocompatibility complex was determined in these tissues. Cells of each immunophenotype had similar distributions in RAMALT and MLNs and these distributions were similar to those reported previously for sheep and cattle. The identification and validation of cervine lymphoid follicle cell markers (CD79 and CD21) may allow reduction in false-negative results during diagnosis of CWD by ELISA.

Increased immunohistochemical labelling for prion protein occurs in diverse neurological disorders of sheep: relevance for normal cellular PrP function

The classical prion diseases (e.g. scrapie of sheep and goats and bovine spongiform encephalopathy of cattle) are characterized by the accumulation of abnormal forms of the prion protein (PrP), usually recognized by their relative resistance to proteolysis compared with the physiological cellular forms of PrP. However, novel prion diseases have been detected in sheep, cattle and man, in which the abnormal PrP has less resistance to proteolysis than identified previously. These more subtle differences between abnormal and normal forms of PrP can be problematic in routine diagnostic tests and raise questions in respect of the range of PrP disorders. Abnormal accumulations of PrP in atypical and classical prion diseases can be recognized by immunohistochemistry. To determine whether altered PrP expression or trafficking might occur in nosological entities not previously connected with prion disease, the brains of sheep affected with diverse neurological conditions were examined for evidence of altered PrP labelling. Such altered immunolabelling was detected in association with either basic lesions or specific diseases. Some reactive glial cells and degenerate neurons found in several different recognized disorders and non-specific inflammatory processes were associated with abnormal PrP labelling, which was absent from brains of healthy, age-matched sheep. The results agree with previous indications that normal PrP function may be linked with the oxidative stress response, but the data also suggest that PrP functions are more extensive than simple protective responses against stress insults.

Adrenocortical carcinoma, an unusual extracolonic tumor associated with Lynch II syndrome

Lynch syndrome (LS) is an autosomal dominant condition that predisposes to colorectal cancer and specific other tumors. Extracolonic tumors occur mainly in the endometrium, stomach, ovary, small intestine and urinary tract. The presence of rare tumors in patients belonging to families who have Lynch syndrome is always interesting, because the question arises whether these tumors should be considered as a coincidence or are related with the syndrome. In this last case, they are also the result of the defect in the mismatch repair system, opening the possibility of extending the tumor spectrum associated with the syndrome. Here we describe a patient from a Lynch syndrome family with a germline mutation c.2063T>G (p.M688R) in the MSH2 gene, who developed an adrenal cortical carcinoma, a tumor not usually associated with LS. We analyzed the adrenocortical tumour for microsatellite instability (MSI), LOH and the presence of the germline c.2063T>G (M688R) mutation. The adrenal cortical carcinoma showed the MSH2 mutation, loss of heterozygosity of the normal allele in the MSH2 gene and loss of immunohistochemical expression for MSH2 protein, but no microsatellite instability. Additionally, the adrenal cortical carcinoma did not harbour a TP53 mutation. The molecular study indicates that this adrenal cortical cancer is probably due to the mismatch repair defect.

Prolonged exposure to GH impairs insulin signaling in the heart

Acromegaly is associated with cardiac hypertrophy, which is believed to be a direct consequence of chronically elevated GH and IGF1. Given that insulin is important for cardiac growth and function, and considering that GH excess induces hyperinsulinemia, insulin resistance, and cardiac alterations, it is of interest to study insulin sensitivity in this tissue under chronic conditions of elevated GH. Transgenic mice overexpressing GH present cardiomegaly and perivascular and interstitial fibrosis in the heart. Mice received an insulin injection, the heart was removed after 2  min, and immunoblotting assays of tissue extracts were performed to evaluate the activation and abundance of insulin-signaling mediators. Insulin-induced tyrosine phosphorylation of the insulin receptor (IR) was conserved in transgenic mice, but the phosphorylation of IR substrate 1 (IRS1), its association with the regulatory subunit of the phosphatidylinositol 3-kinase (PI3K), and the phosphorylation of AKT were decreased. In addition, total content of the glucose transporter GLUT4 was reduced in transgenic mice. Insulin failed to induce the phosphorylation of the mammalian target of rapamycin (mTOR). However, transgenic mice displayed increased basal activation of the IR/IRS1/PI3K/AKT/mTOR and p38 signaling pathways along with higher serine phosphorylation of IRS1, which is recognized as an inhibitory modification. We conclude that GH-overexpressing mice exhibit basal activation of insulin signaling but decreased sensitivity to acute insulin stimulation at several signaling steps downstream of the IR in the heart. These alterations may be associated with the cardiac pathology observed in these animals.

[Absolute lymphocyte count as a prognostic factor in children with acute lymphoblastic leukemia]

INTRODUCTION

Recent studies have suggested that the absolute lymphocyte count (ALC) may be a prognostic indicator in malignant diseases, in that those patients who have higher ALC at certain times during treatment may have a better chance of survival. The influence of T cells and natural killer cells in the immune system of the patient with cancer as a response to cancer cells is particularly noted.

MATERIALS AND METHOD

We prospectively assessed the prognostic value of absolute lymphocytic count (ALC) in 105 pediatric patients with acute lymphoblastic leukemia (ALL), treated in the Cuban Immunology and Hematology Institute from 1995 to 2008. ALC was studied at days 15 (ALC-15) and 28 (ALC-28) of treatment.

RESULTS

In our patients, 1000 cells/uL was the median ALC value for patients who relapsed or died. Using 1000/uL we found that ALL patients with an ALC-15 <1000 cells/μl had a 5-year relapse free survival (RFS) of 51%. In contrast, an ALC-15 >1000 cells/uL showed an excellent prognosis, with a 5-year RFS of 83% (p=0.02). Similarly in our study, an ALC-28 <1000 cells/μl predicted a 5-year overall survival (OS) of 66%, whereas an ALC-28 >1000 cells/μl predicted excellent outcome, with a 5-year OS of 86% (p=0.01). Importantly, ALC is also a strong predictor in multivariate analysis with known prognostic factors. ALC is a simple, statistically powerful measurement for patients with de novo ALL.

CONCLUSIONS

The results, when combined with previous studies, demonstrate that ALC is a powerful new prognostic factor for a range of malignancies.

Benzoxazolin-2(3H)-one (BOA) induced changes in leaf water relations, photosynthesis and carbon isotope discrimination in Lactuca sativa

The effects are reported here of Benzoxazolin-2(3H)-one (BOA), an allelopathic compound, on plant water relations, growth, components of chlorophyll fluorescence, and carbon isotope discrimination in lettuce (Lactuca sativa L.). Lettuce seedlings were grown in 1:1 Hoagland solution in perlite culture medium in environmentally controlled glasshouse. After 30 days, BOA was applied at concentration of 0.1, 0.5, 1.0 and 1.5 mM and distilled water (control). BOA, in the range (0.1-1.5 mM), decreased the shoot length, root length, leaf and root fresh weight. Within this concentration range, BOA significantly reduced relative water content while leaf osmotic potential remained unaltered. Stress response of lettuce was evaluated on the basis of six days of treatment with 1.5 mM BOA by analyzing several chlorophyll fluorescence parameters determined under dark-adapted and steady state conditions. There was no change in initial fluorescence (F₀) in response to BOA treatment while maximum chlorophyll fluorescence (F(m)) was significantly reduced. BOA treatment significantly reduced variable fluorescence (F(v)) on first, second, third, fourth, fifth and sixth day. Quantum efficiency of open PSII reaction centers (F(v)/F(m)) in the dark-adapted state was significantly reduced in response to BOA treatment. Quantum yield of photosystem II (ΦPSII) electron transport was significantly reduced because of decrease in the efficiency of excitation energy trapping of PSII reaction centers. Maximum fluorescence in light-adapted leaves (F'(m)) was significantly decreased but there was no change in initial fluorescence in light-adapted state (F'₀) in response to 1.5 mM BOA treatment. BOA application significantly reduced photochemical fluorescence quenching (qP) indicating that the balance between excitation rate and electron transfer rate has changed leading to a more reduced state of PSII reaction centers. Non photochemical quenching (NPQ) was also significantly reduced by BOA treatment on third, fourth and fifth day. BOA had dominant effect on C isotope ratios (δ¹³C) that was significantly less negative (-26.93) at 1.0 mM concentration as compared to control (-27.61). Carbon isotope discrimination (Δ¹³C) values were significantly less (19.45) as compared to control (20.17) at 1.0 mM. BOA also affect ratio of intercellular to air CO₂ concentration (ci/ca) that was significantly less (0.66) as compared to control (0.69) when treated with 1.0 mM BOA. Protein content of lettuce leaf tissue decreased under BOA treatment at 1.5 mM concentration as compared to control.

The methane cycle in ferruginous Lake Matano

In Lake Matano, Indonesia, the world's largest known ferruginous basin, more than 50% of authigenic organic matter is degraded through methanogenesis, despite high abundances of Fe (hydr)oxides in the lake sediments. Biogenic CH₄ accumulates to high concentrations (up to 1.4 mmol L⁻¹) in the anoxic bottom waters, which contain a total of 7.4 × 10⁵ tons of CH₄. Profiles of dissolved inorganic carbon (ΣCO₂) and carbon isotopes (δ¹³C) show that CH₄ is oxidized in the vicinity of the persistent pycnocline and that some of this CH₄ is likely oxidized anaerobically. The dearth of NO₃⁻ and SO₄²⁻ in Lake Matano waters suggests that anaerobic methane oxidation may be coupled to the reduction of Fe (and/or Mn) (hydr)oxides. Thermodynamic considerations reveal that CH₄ oxidation coupled to Fe(III) or Mn(III/IV) reduction would yield sufficient free energy to support microbial growth at the substrate levels present in Lake Matano. Flux calculations imply that Fe and Mn must be recycled several times directly within the water column to balance the upward flux of CH₄. 16S gene cloning identified methanogens in the anoxic water column, and these methanogens belong to groups capable of both acetoclastic and hydrogenotrophic methanogenesis. We find that methane is important in C cycling, even in this very Fe-rich environment. Such Fe-rich environments are rare on Earth today, but they are analogous to conditions in the ferruginous oceans thought to prevail during much of the Archean Eon. By analogy, methanogens and methanotrophs could have formed an important part of the Archean Ocean ecosystem.

Small nuclear ribonucleoprotein polypeptide N quantitative methylation analysis in infants with central hypotonia

Central hypotonic is one of the most difficult issues in neurology, ruling out neurogenetic syndromic causes is critical, Prader-Willi syndrome (PWS) it is the most frequent genetic syndrome, it is caused by the loss of expression of the paternal allele in a group of imprinted genes within 15q11-q13, and is characterized by severe prenatal and postnatal hypotonia. SNURF-SNRPN gene methylation detects 99% of the cases but fluorescent in situ hybridization (FISH) analysis is necessary to confirm chromosome microdeletions. The advantage of SNRP-quantitative strategy of methylated alleles is that it makes it possible to make the diagnosis and identify deletions and mosaicism in one reaction. In infants clinical diagnosis is difficult. It has been proposed that around 40% of hypotonic patients have PWS but an accurate percentage has not been established. Twenty-four central hypotonic infants were studied by this molecular strategy, showing 41.5% with the disease. This molecular approach also permitted calculation of gene dosage and detection of those cases with microdeletion.

Growth of Low-Density Vertical Quantum Dot Molecules with Control in Energy Emission

In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved. The emission energy of the first layer of QD forming the molecule can be tuned by the deposition of controlled amounts of InAs at a nanohole template formed by GaAs droplet epitaxy. The QD of the second layer are formed directly on top of the buried ones by a strain-driven process. In this way, either symmetric or asymmetric vertically coupled structures can be obtained. As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 10(8) cm(-2)) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required.

Morphological evolution of InAs/InP quantum wires through aberration-corrected scanning transmission electron microscopy

Evolution of the size, shape and composition of self-assembled InAs/InP quantum wires through the Stranski-Krastanov transition has been determined by aberration-corrected Z-contrast imaging. High resolution compositional maps of the wires in the initial, intermediate and final formation stages are presented. (001) is the main facet at their very initial stage of formation, which is gradually reduced in favour of [114] or [118], ending with the formation of mature quantum wires with {114} facets. Significant changes in wire dimensions are measured when varying slightly the amount of InAs deposited. These results are used as input parameters to build three-dimensional models that allow calculation of the strain energy during the quantum wire formation process. The observed morphological evolution is explained in terms of the calculated elastic energy changes at the growth front. Regions of the wetting layer close to the nanostructure perimeters have higher strain energy, causing migration of As atoms towards the quantum wire terraces, where the structure is partially relaxed; the thickness of the wetting layer is reduced in these zones and the island height increases until the (001) facet is removed.

Coeliac disease: clinical features in adult populations

INTRODUCTION

coeliac disease (CD) is a chronic disease of the small intestine, which is caused by gluten intolerance, producing malabsorption of nutrients and vitamins. Clinical manifestations of CD in adults are highly variable, including intestinal and extra-intestinal symptoms. The disease may also occur in individuals who are asymptomatic.

OBJECTIVE

our objective is to describe the incidence and clinical manifestations of CD in adults.

MATERIAL AND METHODS

a retrospective study was carried out in patients diagnosed of CD between January 1990 and December 2008. Diagnosis was based on serologic tests and duodenal biopsy, which were compatible with CD in all of them.

RESULTS

sixty eight adult patients were diagnosed of CD in this period. Mean age was 33 (18-65) years and 50 (74%) were women. The clinical manifestations were diarrhoea in 38 (55%), abdominal pain in 27 (40%), loss of weight in 15 (22%), dyspepsia in 13 (19%). Analytical results showed a slight increase of transaminases in 26 (38%), ferropenic anaemia in 33 (48.5%) cases, sub-clinical hypothyroidism in 3 (4.5%) patients, and folic acid deficiency in 16 (23.5%) cases. Almost all patients were diagnosed between 2000 and 2008: 60 (87%). Population-based incidence of CD in adults had increased from 0.7-2/100,000 per year in the nineties to 3.5-10.3/100,000 in the last years.

CONCLUSIONS

CD can appear at any age and with a wide manifestation spectrum, which can be atypical in some cases. Patients with ferropenic anaemia and a negative response to treatment or those with an unexplained increase in transaminases should be screening for CD. Atypical manifestations and low suspect index can delay diagnosis even during years. There is a marked increase in the incidence-rates of CD in adults over time.

Electrical control of a laterally ordered InAs/InP quantum dash array

We have fabricated an array of closely spaced quantum dashes starting from a planar array of self-assembled semiconductor quantum wires. The array is embedded in a metallic nanogap which we investigate by micro-photoluminescence as a function of a lateral electric field. We demonstrate that the net electric charge and emission energy of individual quantum dashes can be modified externally with the performance limited by the size inhomogeneity of the self-assembling process.

Pathological phenotype of sheep scrapie after blood transfusion

Blood transfusion practices have resulted in iatrogenic cases of variant Creutzfeldt-Jakob disease (vCJD) and it is known that sheep blood is also infectious in the pre-clinical stages of natural scrapie and experimentally induced bovine spongiform encephalopathy (BSE). Further investigations have also shown that the pathological phenotype of sheep BSE and human vCJD is maintained after blood transfusion. The present study describes the pathological phenotype, in terms of accumulation of the disease-associated prion protein in brain and lymphoreticular tissues, in sheep receiving blood from donors infected with natural scrapie. The immunohistochemical examinations undertaken showed a degree of phenotypic variability within and between scrapie donors and recipients, which might be attributable to the presence of more than one scrapie strain amongst the donor sheep or to a host adaptation process, or to the interaction of both, rather than to the influence of the route of infection.

2-3H-Benzoxazolinone (BOA) induces loss of salt tolerance in salt-adapted plants

In order to test the stress hypothesis of allelopathy of Reigosa et al. (1999, 2002), the combined action of a well-established allelochemical compound (2-3H-benzoxazolinone, BOA) and a common abiotic stress (salt stress) were investigated in lettuce (Lactuca sativa L.). In a previous study (Baerson et al. 2005), we demonstrated that the primary effects of BOA are related to the expression of genes involved in detoxification and stress responses, which might serve to simultaneously alleviate biotic and abiotic stresses. Through analysis of the same physiological and biochemical parameters previously studied for BOA alone (Sánchez-Moreiras & Reigosa 2005), we observed specific effects of salt stress alone, as well as for the two stresses together (BOA and salt). This paper demonstrates that plants showing tolerance to salt stress (reduced stomatal density, increased proline content, higher K(+) concentration, etc.) become salt sensitive (markedly low Psiw values, high putrescine content, increased lipid peroxidation, etc.) when simultaneously treated with the allelochemical BOA. We also report additional information on the mechanisms of action of BOA, and general stress responses in this plant species.

Single photon emission from site-controlled InAs quantum dots grown on GaAs(001) patterned substrates

We present a fabrication method to produce site-controlled and regularly spaced InAs/GaAs quantum dots for applications in quantum optical information devices. The high selectivity of our epitaxial regrowth procedure can be used to allocate the quantum dots only in positions predefined by ex-situ local oxidation atomic force nanolithography. The quantum dots obtained following this fabrication process present a high optical quality which we have evaluated by microphotoluminescence and photon correlation experiments.

Surface Localization of Buried III-V Semiconductor Nanostructures

In this work, we study the top surface localization of InAs quantum dots once capped by a GaAs layer grown by molecular beam epitaxy. At the used growth conditions, the underneath nanostructures are revealed at the top surface as mounding features that match their density with independence of the cap layer thickness explored (from 25 to 100 nm). The correspondence between these mounds and the buried nanostructures is confirmed by posterior selective strain-driven formation of new nanostructures on top of them, when the distance between the buried and the superficial nanostructures is short enough (d = 25 nm).

Frequency and distribution of nerves in scrapie-affected and unaffected Peyer's patches and lymph nodes

Transmission of sheep scrapie and some other prion diseases, including variant Creutzfeldt-Jakob disease of man, probably occurs via the oral route. A disease-associated variant of the host-coded prion protein (PrP(d)) accumulates in germinal center follicles of lymphoid tissues, including Peyer's patches of the gut, where it can be detected before its accumulation in the central nervous system. To investigate the potential role of lymphoid tissue nerves in neuroinvasion, we used immunohistochemical methods to study the frequency and distribution of nerves and PrP(d) accumulation in Peyer's patches and other lymphoid tissues from scrapie-affected and unaffected sheep. Nerves were infrequently found in secondary follicles of Peyer's patches, but never in germinal centers of the other lymphoid tissues tested. No differences in the frequency or distribution of nerves were found in relation to the presence or absence of PrP(d) accumulation. PrP(d) accumulation and nerves were only infrequently present together in Peyer's patches. These results suggest that, even if amplification of infectivity in lymphoid tissues facilitates neuroinvasion, nerves within lymph nodes and germinal centers of Peyer's patches do not play a primary role in transport of infectivity to the central nervous system. However, sheep between 2 and 4 months of age had significantly more nerve fibers within follicles than older groups. It is therefore possible that a general increase in nerve density of the intestine during early phases of life may contribute to an increased susceptibility of young animals to oral prion infection.

Site-controlled lateral arrangements of InAs quantum dots grown on GaAs(001) patterned substrates by atomic force microscopy local oxidation nanolithography

In this work, we present a fabrication process that combines atomic force microscopy (AFM) local oxidation nanolithography and molecular beam epitaxy (MBE) growth techniques in order to control both the nucleation site and number of InAs quantum dots (QDs) inside different motifs printed on GaAs(001) substrates. We find that the presence of B-type slopes (As terminated) inside the pattern motifs is the main parameter for controlling the selectivity of the pattern for InAs growth. We demonstrate that either single InAs QDs or multiple InAs QDs in a lateral arrangement (LQDAs) can be obtained, with a precise control in their position and QD number, simply by varying the fabricated oxide length along the [110] direction.

Comparative analysis and clinical value of the expression of metalloproteases and their inhibitors by intratumor stromal fibroblasts and those at the invasive front of breast carcinomas

An immunohistochemical study was performed using tissue arrays and specific antibodies against MMPs -1, -2, -7, -9, -11, -13, -14, and TIMPs -1, -2 and -3. More than 5,000 determinations on cancer specimens from 124 patients with invasive breast cancer were performed at the center of the tumor and the invasive front. Immunostaining for MMPs/TIMPs by fibroblasts was evaluated. To identify specific groups of tumors with distinct expression profiles, the data obtained from both fibroblast populations were analyzed by unsupervised hierarchical cluster analysis. Intratumor stromal fibroblasts more frequently showed expression of MMP-2, -7, and -14, and TIMP-3, but less frequently of MMP-9 than fibroblasts at the invasive front. Multivariate analysis showed that a high profile of MMPs and TIMPs staining in both fibroblast populations was the most potent predictor factor of distant metastases, whereas a low staining profile in fibroblasts was associated with a low risk of metastases.

Pathogenetical significance of porencephalic lesions associated with intracerebral inoculation of sheep with the bovine spongiform encephalopathy (BSE) agent

Decreased rates of transmission of transmissible spongiform encephalopathies (TSEs) to sheep have been attributed to some polymorphisms of the prion protein (PrP) and to a 'species barrier' on interspecies experiments. In addition, the blood-brain barrier may be a further impediment to TSE neuroinvasion. The intracerebral (I/C) route is generally considered the most efficient for TSE transmission, as it may help to bypass those factors. Therefore, susceptibility of particular species to specific TSE agents is conducted by this route.

AIMS

This study characterizes the traumatic brain lesions associated with the I/C injection of the bovine spongiform encephalopathy agent in sheep, assesses the relevance of such lesions in the outcome of clinical disease and provides insight into the mechanisms of PrP(d) conversion and amplification following I/C challenge.

METHODS

A total of 27 hemibrains have been macroscopically and immunohistochemically examined to investigate the presence of lesions compatible with the needle track and the PrP(d) distribution, respectively.

RESULTS

No residual inoculum was found and the extension and severity of the traumatic brain lesions were unrelated to the clinical outcome. Sheep with PrP(d) accumulation in the brain also showed conspicuous focal aggregates in the porencephalic lesions and in the circumventricular organs. In contrast, sheep without PrP(d) deposits in the brain were also negative in the traumatic lesions.

CONCLUSION

Overall, these findings suggest that the efficiency of the I/C route is due to effective absorption and blood recirculation of infection, rather than to primary amplification at the site of injection.

Self-assembling processes involved in the molecular beam epitaxy growth of stacked InAs/InP quantum wires

The growth mechanism of stacked InAs/InP(001) quantum wires (QWRs) is studied by combining an atomic-scale cross-sectional scanning tunnelling microscopy analysis with in situ and in real-time stress measurements along the [110] direction (sensitive to stress relaxation during QWR formation). QWRs in stacked layers grow by a non-Stranski-Krastanov (SK) process which involves the production of extra InAs by strain-enhanced As/P exchange and a strong strain driven mass transport. Despite the different growth mechanism of the QWR between the first and following layers of the stack, the QWRs maintain on average the same shape and composition in all the layers of the stack, revealing the high stability of this QWR configuration.

Exciton gas compression and metallic condensation in a single semiconductor quantum wire

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidence of metallic liquid condensation at low temperatures. First, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Second, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at n{c} approximately 1 x 10;{5} cm;{-1} and T{c} approximately 35 K, respectively.