Gill histopathological and oxidative stress evaluation in native fish captured in Portuguese northwestern rivers

The Northwestern Portuguese region is densely populated and highly industrialized, suffering from high anthropogenic pressure. To assess the biological effect of the several pollutants that are constantly released to the water, a biomarker-based biomonitoring is a promising approach that may provide early-warning signals of pollutants exposure. Fish gill is the first target of pollutants action, thus histopathological and biochemical changes may constitute potential biomarkers. To evaluate this hypothesis, three native fish species (barbel-Luciobarbus bocagei, chub-Squalius carolitertii and nase-Pseudochondrostoma sp.) were sampled in Northwestern Portuguese rivers, the gill histopathological changes were qualitative and quantitatively analyzed and the lipid peroxidation and glutathione-S-transferase activity were determined. A multivariate statistical analysis was performed to establish correlations between these biological responses, environmental variables and ecological status. The quantitative evaluation of the main histopathological changes and oxidative stress responses emphasize the differences, among species, in the responses to the presence of contaminants in water. Discriminant canonical analysis showed that filament epithelium proliferation, necrosis and GST activity were the main contributors to discriminate the ecological status classification. In addition, the results showed that a wide range of environmental factors are influencing fish physiology. In conclusion, the gill biological responses, although not reflecting specific contaminants, can be used as biomarkers of ecosystems perturbation.

Interface formation in monolayer graphene-boron nitride heterostructures

The ability to control the formation of interfaces between different materials has become one of the foundations of modern materials science. With the advent of two-dimensional (2D) crystals, low-dimensional equivalents of conventional interfaces can be envisioned: line boundaries separating different materials integrated in a single 2D sheet. Graphene and hexagonal boron nitride offer an attractive system from which to build such 2D heterostructures. They are isostructural, nearly lattice-matched, and isoelectronic, yet their different band structures promise interesting functional properties arising from their integration. Here, we use a combination of in situ microscopy techniques to study the growth and interface formation of monolayer graphene-boron nitride heterostructures on ruthenium. In a sequential chemical vapor deposition process, boron nitride grows preferentially at the edges of existing monolayer graphene domains, which can be exploited for synthesizing continuous 2D membranes of graphene embedded in boron nitride. High-temperature growth leads to intermixing near the interface, similar to interfacial alloying in conventional heterostructures. Using real-time microscopy, we identify processes that eliminate this intermixing and thus pave the way to graphene-boron nitride heterostructures with atomically sharp interfaces.

Reduced mortality for women with mammography-detected breast cancer in east Denmark and south Sweden

The 5-year relative survival from breast cancer in Denmark is 10 percentage points lower than in Sweden. This difference has been demonstrated previously as being caused partly by more involved lymph nodes and larger tumours in Denmark. Sweden has had nationwide mammography-screening coverage since 1991, whereas this is still in its infancy in Denmark. In the search for an explanation for the remaining survival difference, patient delay was a likely candidate. This study compared patient delay and mammography-detection between two national regions. Data on patient delay and mammography were obtained from hospital records from 1989 and 1994, and analysed using Cox proportional hazard analysis of death within the first 5 years, with the factors age, country, delay/mammography detection and established patho-anatomic variables. A comparison of patient delay and mammography detection in 1989 and 1994 showed more mammography-detected tumours in south Sweden and more women with long delay in east Denmark. Mammography detection, but not long patient delay, had a significant effect on the death hazard when adjusting for patho-anatomic risk factors. The hazard ratio was not eliminated in 1989, but in 1994, the hazard ratio between east Denmark and south Sweden was reduced from 1.3 to 1.1. In conclusion, patient delay did not appear to have any effect on 5-year survival when adjusting for patho-anatomic factors, but tumour detection by mammography affected survival favourably and partly explained the survival difference between east Denmark and south Sweden.

Structural properties of Y1-xYbxNi2B2C synthesized at high pressure: EXAFS data analysis

Local structure of Y(1-x)Yb(x)Ni2B2C series synthesized at high pressure 8 GPa has been studied using EXAFS. Measurements were performed at the Ni K-edge in temperature range 5-300 K. The results show that the Debye-Waller factor for Ni-Ni bond in the parent YNi2B2C compound is characterized by the Einstein temperature O(E) = 350 K, while a minimum value O(E) = 300 K is reached for the compound with = 0.025, which has the highest critical temperature T(c) = 12.5K of the superconductive transition. This correlates with the further suppressing of superconductivity and with the appearance of the local magnetic moments in the investigated Y(1-x)Yb(x)Ni2B2C series for x > or = 0.05 compounds. Observed changes in the local electronic and the local crystal structure of this system as a function of Yb concentration and of temperature were explained in the frame of the band filling effect.

Lattice softening in superconducting compositions of Ba(K)BiO3

Temperature dependent x-ray absorption spectra investigation were measured for Ba(1-x)K(x)BiO3 (Bi L3-edge) with x =0.0, 0.25, 0.4, 0.5 and for BaPbO3 (Pb L3-edge). It was found that at low temperatures the Debye-Waller factor of the square diagonal Bi-Bi bond has the maximum value near the insulator-metal phase transition for the compound with x = 0.25 and x = 0.4. Temperature dependence of the Debye-Waller factor of Bi-Bi bond strongly differs from the Einstein model curve that well describes the harmonic systems (for example BaPbO3). This behavior is consistent with the strong anharmonicity of the Bi-O shell due to the double-well vibration potential reported by us earlier. Presented results point to the essential lattice softening of the superconducting compositions, which is important for the understanding of superconductivity mechanism in perovskite type oxides.

Malignant nodular hidradenoma

A 54-year-old male farmer was seen in May 1990 with a violaceous, exulcerated tumor, 2x1.5 cm in diameter, localized to the sternal area of the chest. The tumor had been present for 30 years, showing slow progressive growth; it was excised, but recurred 2 years before our initial evaluation. The tumor was again excised with a wide free margin. The histopathologic study showed an ill-defined, epithelial neoformation, formed by lobules of clear polygonal cells at the deep dermis and subcutaneous tissue; there was a second group of smaller cells with a basaloid aspect, a few of them presenting slight atypia. The tumoral lobules were surrounded by a myxoid material with vascular proliferation. The epidermis was normal. The histopathologic report was of a malignant nodular hidradenoma. No evidence of lymph node or distant metastases was found. One year after the excision, the tumor recurred at the surgical site, and an axillary lymph node showed metastatic cells. The lesion was excised for a third time and the patient was lost to follow-up.

Distribution of [3H]diadenosine tetraphosphate binding sites in rat brain

The distribution of the diadenosine tetraphosphate high-affinity binding sites has been studied in rat brain by an autoradiographic method using [3H]diadenosine tetraphosphate as the ligand. The binding characteristics are comparable to those described in studies performed on rat brain synaptosomes. White matter is devoid of specific binding. The range of binding site densities in gray matter varies from 3 to 15 fmol/mg of tissue, exhibiting a widespread but heterogeneous distribution. The highest densities correspond to the seventh cranial nerve, medial superior olive, pontine nuclei, glomerular and external plexiform layers of the olfactory bulb, and the granule cell layer of the cerebellar cortex. Intermediate density levels of binding correspond to different cortical areas, several nuclei of the amygdala, and the oriens and pyramidal layers of the hippocampal formation. The localization of diadenosine tetraphosphate binding sites in the brain may provide information on the places where diadenosine polyphosphate compounds can be expected to function in the central nervous system.

Prevalence of mental disorder in military children and adolescents: findings from a two-stage community survey

OBJECTIVE

Because previous reports have suggested that children of military families are at greater risk for psychopathology, this study examines the levels of psychopathology in an epidemiological community sample of military children all living on a military post.

METHOD

Standardized psychopathology rating scales and a structured diagnostic interview (the Diagnostic Interview Schedule for Children [DISC], version 2.1) were used in a multimethod, multistage survey; 294 six- to seventeen-year-old military children and their parents participated in the study.

RESULTS

Parent- and child-administered structured DSM-III-R DISC interviews indicated that children's levels of psychopathology were at levels consistent with studies of other normal samples. In addition, parents' and children's symptom checklist ratings of children were at national norms, as were parents' ratings of their own symptoms.

CONCLUSIONS

Overall results do not support the notion that levels of psychopathology are greatly increased in military children. Further studies of military families should address the effects of rank and socioeconomic status, housing, and the current impact of life stressors on the parents as well as the children, in order to avoid drawing erroneous conclusions about parts or all of the military community.

Comparison of derivatization procedures for the determination of diuretics in urine by gas chromatography-mass spectrometry

Three different GC-MS screening procedures, which use different ways of derivatization (methylation), are compared. In the first one, derivatization with iodomethane in acetone and a previous solid-liquid extraction is used; the second one is based on an extractive alkylation method using iodomethane in toluene (liquid-liquid extraction); and the last one is flash methylation by pyrolysis of tetraalkylammonium salts in the injector of the gas chromatograph using trimethylanilinium as the derivatization agent. The speed of the extraction, reproducibility and accuracy have been compared for 20 diuretics including the ones most often used in sports, such as bumetanide, ethacrynic acid, acetazolamide, dichlorphenamide, furosemide, hydroflumethiazide, hydrochlorothiazide and chlorthalidone; they have also been applied to the two uricosuric agents probenecid and benzbromarone.

Psychometric analysis in children with mental retardation due to perinatal hypoxia treated with fibroblast growth factor (FGF) and showing improvement in mental development

Basic fibroblast growth factor (bFGF) has shown a neurotrophic effect in the neurons of several CNS areas. In vivo, it contributes to restore neurochemical and morphological deficits in different rodent models of brain damage, including rats with brain damage induced by hypoxia/ischemia when FGF was intramuscularly (i.m.) administered. Toxicological and immunological studies performed in rats, mice and volunteers showed no evidence of side-effects. Bovine FGF was i.m. administered in children with mental retardation caused by perinatal hypoxia, aged 1-15 years, at dosages of 0.4 or 0.28 microgram kg-1, once or twice a month, over 7-12 months. Group A [n = 12; 6 treated (T), 6 controls (Ct)], group B (n = 16; 8 T, 8 Ct) and group C (n = 67; 45 T, 22 Ct) were evaluated with the P. A. R. scale, the WISC-RM and the Gesell scale, respectively. Development increased significantly in treated children from groups A (P < 0.02) and C (P < 0.001), and IQ rose by more than 10 points (P < 0.001) in group B patients.