Simple and reliable method to simultaneously determine urinary 1- and 2-naphthol using in situ derivatization and gas chromatography-mass spectrometry for biological monitoring of naphthalene exposure in occupational health practice.

OBJECTIVES: The aim of this study was to develop and validate a simple and reliable gas chromatography-mass spectrometry (GC-MS) method to simultaneously determine urinary 1-naphthol (1-NAP) and 2-naphthol (2-NAP) for biological monitoring of occupational exposure to naphthalene. METHODS: NAPs were derivatized in situ with acetic anhydride after enzymatic hydrolysis, extracted with n-hexane, and analyzed using GC-MS. Validation of the proposed method was conducted in accordance with US Food and Drug Administration guidance. A final validation was performed by analyzing a ClinChek® -Control for phenolic compounds. RESULTS: The linearity of calibration curves was indicated by a high correlation coefficient (>0.999) in the concentration range 1-100 µg/L for each NAP. The limits of detection and quantification for each NAP were 0.30 and 1.00 µg/L, respectively. The recovery was 90.8%-98.1%. The intraday and interday accuracies, expressed as the deviation from the nominal value, were 92.2%-99.9% and 93.4%-99.9%, respectively. The intraday and interday precision, expressed as the relative standard deviation, was 0.3%-3.9% and 0.4%-4.1%, respectively. The ClinChek® values obtained using our method were sufficiently accurate. CONCLUSIONS: The proposed method is simple, reliable, and appropriate for routine analyses, and is useful for biological monitoring of naphthalene exposure in occupational health practice.

Imaging diagnosis--polioencephalomalacia in a calf.

A 2-month-old mix-breed calf developed acute blindness and ataxia. Serum thiamine concentration was deficient. In antemortem magnetic resonance imaging there were laminar T2-hyperintense regions extending along the cerebral cortex that primarily affected the gray matter. The lesions were relatively symmetric between the left and right hemispheres but no abnormalities were present at the frontal lobes. At necropsy, laminar autofluorescence of the cerebral cortex was observed under ultraviolet exposure at 365 nm, consistent with a diagnosis of polioencephalomalacia. Polioencephalomalacia in the bovine species is compared with that in other species, namely humans, dogs, and cats.

Transorbital echoencephalography in cattle.

The purpose of this study was establishment of the criteria of transorbital echoencephalography in cattle and experimental applications to bovine practice. Quantitative investigations using magnetic resonance (MR) imaging revealed that this examination could be applied to cattle under 3 months of age. The method of transducer positioning was established in Japanese Black (J.B.) and filial (F1) cattle (turning caudally at an angle of about 16 degrees and dorsally at an angle of about 23 degrees) or in Holstein cattle (turning caudally at an angle of about 20 degrees and dorsally at an angle of about 21 degrees). Examinations in clinical calves revealed that the cerebral parenchyma and the lateral ventricle could be detected antemortem or postmortem. In this study, the diagnoses of hydrocephalus or hydranencephaly was possible using antemortem transorbital echoencephalography. Transorbital echoencephalography was especially useful as the imaging method for bovine hydranencephaly.

Copper(II) Complexes of N,N'-Bis((2-substituted-imidazol-4-yl)methylene)-3,3'-diaminodi- propylamine (2-Substituent = H, Me): Delta and Lambda Enantiomorphs of the Protonated Complex and Helical Structure of the Deprotonated Complex Formed by Hydrogen Bonds.

Copper(II) complexes with the quinquedentate ligands H(2)L(n)() (n = 1, 2) of the 1:2 condensation products of 3,3'-diaminodipropylamine and each of 4-formylimidazole and 4-formyl-2-methylimidazole have been synthesized and characterized, where the complexes have the general formula of [Cu(H(2)L(n)())]X(2) and are abbreviated as 1X(2), and 2X(2) (n = 1, 2 for 2-substituent = H, Me; X = ClO(4), NO(3), Cl). X-ray crystal structures of 1(NO(3))(2), and 2(Cl)(2) were determined: 1(NO(3))(2), monoclinic, space group P2(1)/c (No. 14), a = 9.610(4) Å, b = 13.463(5) Å, c = 15.568(5) Å, beta = 98.12(3) degrees, and Z = 4; 2(Cl)(2), monoclinic, space group P2(1)/n (No. 14), a = 9.884(2) Å, b = 15.073(3) Å, c = 15.295(2) Å, beta = 98.57(2) degrees, and Z = 4. The complex assumes Delta or Lambda enantiomorphs due to the spiral arrangement of the quinquedentate ligand around the copper(II) ion, and these Delta and Lambda enantiomorphs of the cation for 1(NO(3))(2) and 2(Cl)(2) coexist as the racemic form in the crystals. When the protonated complexes were treated with NaOH, the mono-deprotonated complexes with the formula [CuHL(n)()]ClO(4), 1'ClO(4) (n = 1) and 2'ClO(4) (n = 2), were obtained. Crystal data for 1'ClO(4): Pbca (No. 61) with a = 13.211(3) Å, b = 25.387(3) Å, c = 10.939(3) Å, and Z = 8.; 2'.ClO(4), Pbca (No. 61) with a = 16.554(4) Å, b = 20.609(4) Å, c = 12.423(3) Å, and Z = 8. The structures consist of an electronically monopositive copper(II) complex involving a deprotonated imidazole moiety and a protonated imidazole moiety per molecular unit and a mononegative anion ClO(4)(-), where an imidazolate nitrogen atom N(2) of the copper(II) complex is hydrogen bonded to the imidazole nitrogen atom N(6) ( denotes the symmetry operation of (1)/(2) + x, (1)/(2) - y, -z) of the adjacent unit with the hydrogen bond distance of N(2).N(6) of 2.842(6) for 1'ClO(4) and 2.815(4) Å for 2'ClO(4) to give a one-dimensional helical structure running along the a-axis. Through the hydrogen bonds, the Delta isomer only aggregates with the Delta isomer and the Lambda isomer only aggregates with the Lambda isomer to give an extended helical chain structure described as DeltaDeltaDeltaDeltaDelta. or LambdaLambdaLambdaLambdaLambda., respectively.