Ractopamine and Other Growth-Promoting Compounds in Beef Cattle Operations: Fate and Transport in Feedlot Pens and Adjacent Environments.

The current study represents a comprehensive investigation of the occurrence and fates of trenbolone acetate (TBA) and metabolites 17α-trenbolone (17α-TBOH), 17ß-TBOH, and trendione (TBO); melengesterol acetate (MGA); and the less commonly studied ß-andrenergic agonist ractopamine (RAC) in two 8 month cattle feeding trials and simulated rainfall runoff experiments. Cattle were administered TBA, MGA, or RAC, and their residues were measured in fresh feces, pen floor material, and simulated rainfall runoff from pen floor surfaces and manure-amended pasture. Concentrations of RAC ranged from 3600 ng g-1, dry weight (dw), in pen floor to 58 000 ng g-1 in fresh feces and were, on average, observed at 3-4 orders of magnitude greater than those of TBA and MGA. RAC persisted in pen floors (manure t1/2 = 18-49 days), and contamination of adjacent sites was observed, likely via transport of windblown particulates. Concentrations in runoff water from pen floors extrapolated to larger-scale commercial feedlots revealed that a single rainfall event could result in mobilization of gram quantities of RAC. This is the first report of RAC occurrence and fate in cattle feedlot environments, and will help understand the risks posed by this chemical and inform appropriate manure-management practices.

A high-nuclearity metal-cyanide cluster [Mo6Cu14] with photomagnetic properties.

A high-nuclearity metal-cyanide cluster [Mo6Cu14] has been prepared and its photomagnetic properties investigated. The photoswitchable magnetic phenomenon observed is thermally reversible (T≈ 230 K). In the field of photomagnetism, [Mo6Cu14] represents a unique example of a nanocage and the highest nuclearity observed so far.

Validity and reproducibility of a food frequency questionnaire focused on the Mediterranean diet for the Quebec population.

BACKGROUND AND AIMS: Validated dietary assessment methods specific to population and food habits are needed to conduct randomized clinical trials evaluating the efficacy of the Mediterranean diet in primary and secondary prevention of cardiovascular disease. Therefore, the aim of our study was to assess the reproducibility and the relative validity of a French language semi-quantitative food frequency questionnaire (FFQ) focused on the Mediterranean diet within the population of Quebec. METHODS AND RESULTS: Fifty-three participants aged 19-86 years with and without coronary heart disease were recruited, and randomized in 3 groups in a crossover design where the sequence of administration of two FFQs and a dietary record (DR) differed in each group. The FFQ includes 157 food items and was designed to measure food intake over one month. It was administered twice 3-5 weeks apart to assess reproducibility and was compared to a 12-day DR to assess validity. For reproducibility (n = 47), intraclass correlation coefficients (ICCs) for energy and 33 nutrients ranged from 0.38 to 0.91 (mean 0.63). For validity, the Pearson's correlation coefficients between the DR and the FFQ pre-DR ranged from 0.26 to 0.84 (mean 0.55) and ICCs ranged from 0.25 to 0.84 (mean 0.54). As for the DR and the FFQ post-DR, the Pearson's correlation coefficients ranged from 0.36 to 0.83 (mean 0.55) and the ICCs ranged from 0.36 to 0.83 (mean 0.53). CONCLUSION: This FFQ demonstrates good reproducibility and validity for most key nutrients of the Mediterranean diet for the Quebec population.

First evidence of light-induced spin transition in molybdenum(IV).

Photo-induced spin transition in a molybdenum-zinc complex has been evidenced and fully characterized by Squid magnetometry and several spectroscopies performed under irradiation (IR, EPR, etc.). The phenomenon has been confirmed by X-ray diffraction and DFT calculations yielding a Light-Induced Excited Spin State Trapping Effect (LIESST) on a 4d transition metal ion.

Identification of the nitrogen split interstitial (N-N)(N) in GaN.

Combining electron paramagnetic resonance, density functional theory, and positron annihilation spectroscopy (PAS), we identify the nitrogen interstitial defect in GaN. The isolated interstitial is unstable and transforms into a split interstitial configuration (N-N)(N). It is generated by particle irradiation with an introduction rate of a primary defect, pins the Fermi level at E(C)-1.0 eV for high fluences, and anneals out at 400 °C. The associated defect, the nitrogen vacancy, is observed by PAS only in the initial stage of irradiation.

Alterations to locomotor navigation in a complex environment at 7 and 30 days following a concussion in an elite athlete.

PRIMARY OBJECTIVE: To compare the locomotor capacity during (1) unobstructed walking and (2) the circumvention of fixed obstacles with and without a simultaneous visual task in an elite athlete before and after a sports-related concussion. RESEARCH DESIGN: Case report. METHODS AND PROCEDURES: Gait analysis and clinical neuropsychological measures were taken pre- and at 7 and 30 days post-injury in an 18 year old male junior hockey player. The task consisted of walking along an unobstructed or obstructed path with or without a visual interference task. Measurements included dual tasks costs, response errors, maximal gait speed and minimal clearance with the obstacle. MAIN OUTCOME AND RESULTS: Although the athlete was symptom-free and neuropsychological test results returned to baseline relatively quickly, he showed continued errors in the interference task, abnormally small obstacle clearance distances and decreased maximal gait speed up to 30 days after the concussion. CONCLUSIONS: Concussion can result in persistent planning and attention deficits in ecologically valid, complex environments. This report suggests that functional assessment within an ecological context could be an innovative way to evaluate concussed athletes before sending them back to play, even in the absence of medically related symptoms or abnormal neuropsychological test results.

Peritonitis due to Blastobotrys proliferans in a patient undergoing continuous ambulatory peritoneal dialysis.

Blastobotrys proliferans is an ascomycetous yeast never previously reported as a human pathogen. Here we report a case of peritonitis due to Blastobotrys proliferans in a 46-year-old man undergoing peritoneal dialysis.

Identification of the carbon dangling bond center at the 4H-SiC/SiO(2) interface by an EPR study in oxidized porous SiC.

We report the observation of a paramagnetic interface defect in thermally oxidized porous n-type doped 4H-SiC/SiO(2). Based on its axial symmetry and resolved hyperfine interactions it is attributed to an sp(3) carbon dangling bond center situated at the SiC side of the interface. This center is electrically active and pins the Fermi level in the oxidized samples. No silicon related paramagnetic dangling bond centers are observed. The formation of dangling bond centers seems to be related to interstitial oxygen diffusion at the interface during the oxidation process.

Neurobehavioral changes in mice treated with methylmercury at two different stages of fetal development.

Pregnant C57BL/6 mice were orally given daily doses of 4 or 6 mg/kg of methylmercury chloride (MeHg) or vehicle during either gestational days 7-9 (GD7-9) or days 12-14 (GD12-14). Their female offspring were tested between 6 and 16 weeks of age on a variety of behavioral tasks. Motor coordination on the rotarod and visual discrimination learning in the Y maze were not affected by administration of MeHg either at GD7-9 or at GD12-14. In the open field, the total number of square crossings was lower in mice treated with 4 and 6 mg/kg of MeHg at GD12-14 than in control mice whether the environment was new or familiar, but prenatal administration of MeHg at GD7-9 had no effect on this measure. Administration of MeHg either at GD7-9 or at GD12-14 had no effect on the percentage of central square crossings or on the frequency of rearings in the open field. On spatial alternation training in the T maze, both treated groups in Condition GD7-9 and the group treated with 6 mg/kg at GD12-14 required more sessions to reach the learning criterion than their respective vehicle groups. When spatial alternation was tested with delays, treated groups did not differ from their respective control groups. In the radial arm maze, the performance of mice treated at GD7-9 was normal, but reference memory and working memory were impaired by administration of MeHg at GD12-14. In mice treated with 4 mg/kg of MeHg, reference memory was impaired only on the first block of trials, whereas in mice treated with 6 mg/kg, the deficit persisted on all blocks of trials. Overall, these results indicate that prenatal administration of MeHg at GD12-14 had more detrimental effects on behavioral performance than administration at GD7-9. It reduced locomotor activity and impaired reference memory for egocentric and allocentric spatial information as well as working memory for places.

Clinical practice guidelines for the care and treatment of breast cancer: 13. Sentinel lymph node biopsy.

OBJECTIVE: To provide information and recommendations to women with breast cancer and their physicians regarding what is now known about sentinel lymph node (SLN) biopsy. OPTIONS: Axillary dissection; SLN biopsy followed by backup axillary dissection; SLN biopsy. OUTCOMES: Accurate determination of cancer stage, resulting in better-informed therapeutic decisions. EVIDENCE: Systematic review of English-language literature published from January 1991 to December 2000 retrieved primarily from MEDLINE and CANCERLIT. RECOMMENDATIONS: Axillary dissection is the standard of care for the surgical staging of operable breast cancer. If a patient requests or is offered SLN biopsy, the benefits and risks as well as what is and is not known about the procedure should be outlined. Patients should be informed of the number of SLN biopsies performed by the surgeon and the surgeon's success rate with the procedure, as determined by the identification of the SLN and the false-negative rate (the presence of tumour cells in the axillary nodes when the SLN biopsy result is negative). Before surgeons replace axillary dissection by SLN biopsy as the staging procedure at their institution, they should (a) familiarize themselves with the literature on the topic and the techniques needed to perform the procedure, (b) follow a defined protocol for all 3 aspects of the procedure (nuclear medicine, surgery, pathology) and (c) perform backup axillary dissection until an acceptable success rate (as determined by the identification of the SLN and the false-negative rate) is achieved. A surgeon who performs breast cancer surgery infrequently should not perform SLN biopsy. A positive SLN biopsy result or failure to identify an SLN should prompt full axillary dissection. SLN biopsy is contraindicated in women who have clinically palpable nodes, locally advanced breast cancer, multifocal tumours, previous breast surgery or previous irradiation of the breast. Staining of tissue sections with hematoxylin and eosin, and not immunohistochemical analysis for cytokeratin, should determine adjuvant therapy. Participation in randomized clinical trials is encouraged. [A patient version of these guidelines appears in Appendix 1.] VALIDATION: Internal validation within the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer; no external validation.

Prevalence of founder BRCA1 and BRCA2 mutations in unselected French Canadian women with breast cancer.

The frequency of BRCA1 and BRCA2 mutations in women with breast cancer varies according to the age at diagnosis, family history of cancer, and ethnicity/country of origin. We set out to estimate the frequency of seven previously described founder mutations in BRCA1 and BRCA2 in all eligible French Canadian women diagnosed with invasive breast cancer at one Montreal hospital over a 20-month period. One hundred and ninety-two patients were eligible and 127 (66.2%) provided blood for genetic testing. We identified 4 women who carried a founder mutation (3.1%, 95% confidence interval 0.9-7.9%) in this population. Interestingly, all the mutations were in BRCA2. The mean age at diagnosis for mutation carriers was 51.2 years (range 49.1-53.5). Two of these 4 cases were lobular invasive carcinomas and 2 were ductal carcinomas, histological grade 1 or 2. Despite a small tumor size (< or =20 mm), axillary nodal involvement was present in 3 women. Estrogen receptors were strongly expressed in all cases. Two of the 4 cases reported a strong family history of breast cancer, but a family history of site-specific breast cancer was a relatively poor indicator of the presence of BRCA2 mutations. The absence of BRCA1 mutations may be a result of chance, but may also reflect different geographical origins of the most common BRCA1 mutations within the French Canadian population.

Role of metalloproteases and inhibitors in the occurrence and progression of diabetic renal lesions.

Renal remodelling in hyperinsulinic/insulinopenic states is mediated by glucotoxicity, endothelial dysfunction and vascular and nephron collagen turnover. Hypertensive and renal links are renewed by renoprotective interventions of renin-angiotensin. Vasoactive peptide processing and vascular collagen deposition are under the tight control of two zinc metalloproteinase families that regulate vascular tone and trophicity: gluzincins (or vasopeptidases) are convertases of angiotensins, endothelins or atrial natriuretic factors; and metzincins or matrix metalloproteases (MMP, matrixins)] regulate vascular type IV collagen basement membrane proteolysis. Association of natural tissue inhibitors of MMPs, pharmacological inhibitors of vasopeptidases [either conventional (angiotensin-converting enzyme inhibitors) or innovative (omapatrilat)], together with synthetic MMP inhibitors, are currently screened to counteract vascular remodelling and renal scarring. Our studies focused on the 72 kDa (MMP-2) and 92 kDa (MMP-9) matrixin gelatinases and tissue inhibitors involved in basement membrane degradation and rebuilding. Three complementary settings were developed, allowing evaluations from basic to clinical stages. A leucocyte-endothelial transmigration model was designed for transcription and addressing of enzymes and inhibitors, in situ matrix degradation, and blockading by metalloprotease inhibitors (captopril). Insulin-resistant fructose-fed rats showed heavy proteinuria and glomerulosclerosis involving angiotensin II-dependent changes in renal gelatinases and inhibitors. Urinary gelatinolytic profiles from Type 2 diabetic patients with overt nephropathy were compared with those of normal first-degree relatives and age-matched healthy controls. Physiologically, MMP-9 was the primary urinary gelatinolytic enzyme. In Type 2 diabetic proteinuric patients, MMP-9 and MMP-2 releases were significantly increased in the absence of renin-angiotensin blockade, while first-degree relatives showed reduced gelatinase levels suggestive of a genetic control of renal matrix regulation prior to potential glycaemic dysregulation. These preliminary data suggest that local MMP/TIMP imbalance is involved in diabetic renal remodelling. Further studies are needed to define the redundancies and specificities of vasopeptidase and MMP inhibitors, differentiate the antihypertensive effect from target-organ protection, screen for innovative pharmacological compounds, and validate simple, efficient biological markers of renal fibrosis progression and the effect of anti-fibrotic therapeutic interventions.

[Heterogeneity of nephropathies in type 2 diabetes]. / Hétérogénéité de la néphropathie chez les diabétiques de type 2.

DIVERSE KIDNEY DISORDERS: Patients with type 2 diabetes mellitus who develop nephropathy can have various types of disorders capable of progressively destroying the kidneys. It is now clear that the same type of diffuse or nodular glomerulosclerosis develops irrespective of the type of diabetes, i.e. the pathophysiology of hyperglycemia. HETEROGENEITY: There is however a certain degree of heterogeneity in terms of clinical presentation, clinical course and response to treatment. Heterogeneity is due to age, the number of different accumulated risk factors and disease states, genetic factors that are in the process of being identified, and finally, lesions to the urologic apparatus, the arteries, and the renal parenchyma itself that are not directly caused by diabetes. PRACTICAL IMPACT: Mixed lesions, due to both diabetic and non-diabetic causes, may therefore exist in the same kidney. These different possibilities should be systematically considered in order to adopt an individualized investigative and therapeutic attitude for each new patient.

SB7: the new bending-magnet double-headed dragon beamline at SuperACO.

A new beamline is now operational at LURE on bending-magnet 7 of the SuperACO storage ring in Orsay. The monochromator is of the ;dragon' type, designed to work in the energy range 150-1500 eV, and is equipped with a double vertical focusing mirror in order to allow for fast switching of light polarization. In this paper the results of photoion-yield experiments performed on N(2), Ar and Ne gases are presented. The observed resonance structures enable us to determine the available energy resolution: a resolving power higher than 8500 is obtained at the Ar 2p, N 1s and Ne K-edges when using all the optical elements at full aperture. The total flux as a function of the measured photon energy resolution and the characterization of the double-head behaviour in delivering circularly polarized light are reported.

Metastatic axillary lymph node technetium-99m-MIBI imaging in primary breast cancer.

UNLABELLED: Technetium-99m-MIBI scintimammography has been shown to be useful in the detection of primary breast cancer. The purpose of this study was to evaluate the potential role of scintimammography in detecting axillary lymph node involvement in patients undergoing scintimammography to detect primary breast cancer. METHODS: A group of 100 women with breast cancer who were scheduled for a Level I-II axillary dissection were prospectively studied. Scintimammography was performed in all patients before histopathologic confirmation of breast cancer. Two lateral (prone imaging) views and one anterior (supine) planar thoracic view were obtained 10-15 min after the injection of 25-30 mCi 99mTc-MIBI (10 min/view) by using a special breast positioning device (foam cushion) placed over the imaging table. Both of the axilla were included in the field-of-view. Two experienced blinded observers reviewed all cases both from films and from the computer screen with contrast adjustment when needed. The site of intravenous injection of 99mTc-MIBI was known to the interpreters in order to avoid reading any false-positive uptake in the axilla ipsilateral to the injection site. RESULTS: A total of 52 patients had no axillary lymph node involvement (611 negative nodes) while 48 patients had at least one axillary lymph node with metastatic involvement (180/502 positive nodes). The sensitivity of scintimammography in detecting metastatic axillary lymph node involvement was 79.2% (38/48), and the specificity was 84.6% (44/52). The positive and the negative predictive values were 82.6% (38/46) and 81.5% (44/54), respectively. CONCLUSION: This study shows that scintimammography has good diagnostic accuracy for detecting axillary lymph node involvement in patients with breast cancer. This information should be added to the result of standard scintimammography, which requires very minor modifications in order to simultaneously evaluate both of the axilla.

Proper positioning eliminates patient injury.

1. Pre-existing disorders such as poor nutritional state, diabetes, respiratory disorders arthritis, and cardiac status compound the effects of positioning. 2. Under anesthesia, the patient may be placed in a potentially injurious position that he could protect himself against otherwise. 3. Position influences respiration by mechanical restriction of the ribs and sternum, and by reduced ability of the diaphragm to push down against the abdominal contents. 4. Informed involvement of the operating room nurse will minimize risk to the patient who is defenseless under anesthesia.

Intra-arterial infusion chemotherapy in rectal cancer.

Chemotherapy by intra-arterial infusion, using mitomycin C and 5-fluorouracil, was administered to six patients with cancer of the rectum. In three patients who presented initially with an inoperable rectal tumour, medication was infused through the inferior mesenteric artery. Tumour regression was documented in all three, allowing subsequent resection in two. Of three other patients with locally recurrent rectal cancer, none showed tumour regression after infusion, but two experienced substantial relief of perineal pain, with improvement in the quality of life. Unexpected complications occurred in the form of a reversible ischemic colitis in two patients and an arterioenteric fistula in a third.