Treatment of fractures of the tibial tuberosity in the dog.

Of 27 dogs with fractures of the tibial tuberosity, 24 were treated by various methods of open reduction. Follow-up examination was obtained in 21 cases, and it was found that all but one fracture healed in 8 weeks. Tension band wiring and single interfragmentary screws were most commonly used; healing was similar in both groups.     

Necrotizing meningoencephalitis and pneumonitis in a simian immunodeficiency virus-infected rhesus macaque due to Acanthamoeba

Free-living amoebae of the genus Acanthamoeba can cause a fatal disease of the brain in humans called granulomatous amoebic encephalitis. We present a case of meningoencephalitis and pneumonitis in a simian immunodeficiency virus (SIV)-infected rhesus macaque caused by Acanthamoeba sp. The animal became ill 176 days after intravenous inoculation with SIVmac251 after a short history of weight loss and a sudden onset of hind limb paresis and abnormal head movements. Histopathologic examination of hematoxylin and eosin-stained tissues revealed multifocal to coalescing necrotizing neutrophilic meningoencephalitis and pneumonitis. Immunofluorescence and polymerase chain reaction were used to identify the genus of amoeba as Acanthamoeba. Immunohistochemistry of immune cell markers was used to characterize the animal's immune response to the opportunistic amoebic infection with features of both innate and adaptive cell-mediated immunity. Although not previously reported, the potential transmission to humans, either through environmental contamination or contact with an infected animal, makes this disease a threat to laboratory animal care staff and pathologists.     

Physiological insights into Shechita

The Government recently announced that it intends to reject a recommendation by the Farm Animal Welfare Council that all animals should be stunned before slaughter (see VR, April 10, p 446). In this Viewpoint article, Dr Stuart Rosen discusses physiological aspects of Shechita, the Jewish method of religious animal slaughter. He outlines the religious context and describes the act of Shechita. He discusses the scientific literature on the behavioural responses to Shechita as well as neurophysiological studies relevant to the assessment of pain, and concludes that Shechita is a painless and humane method of animal slaughter.     

Ionic liquid-mediated selective conversion of CO₂ to CO at low overpotentials

Electroreduction of carbon dioxide (CO(2))--a key component of artificial photosynthesis--has largely been stymied by the impractically high overpotentials necessary to drive the process. We report an electrocatalytic system that reduces CO(2) to carbon monoxide (CO) at overpotentials below 0.2 volt. The system relies on an ionic liquid electrolyte to lower the energy of the (CO(2))(-) intermediate, most likely by complexation, and thereby lower the initial reduction barrier. The silver cathode then catalyzes formation of the final products. Formation of gaseous CO is first observed at an applied voltage of 1.5 volts, just slightly above the minimum (i.e., equilibrium) voltage of 1.33 volts. The system continued producing CO for at least 7 hours at Faradaic efficiencies greater than 96%.     

Beta-1C-globulin: metabolism in glomerulonephritis

The metabolism of beta(1C)-globulin labeled with iodine-131 was studied in six normal individuals and in three individuals with glomerulonephritis who exhibited markedly reduced serum concentrations of this protein. Fractional of serum beta(1C)-globulin in glomerulonephritis appears to be chiefly secondary to decreased synthesis.     

A cDNA for a protein that interacts with the human immunodeficiency virus Tat transactivator

The human immunodeficiency virus (HIV) tat protein (Tat) is a positive regulator of virus gene expression and replication. Biotinylated Tat was used as a probe to screen a lambda gt11 fusion protein library, and a complementary DNA encoding a protein that interacts with Tat was cloned. Expression of this protein, designated TBP-1 (for Tat binding protein-1), was observed in a variety of cell lines, with expression being highest in human cells. TBP-1 was localized predominantly in the nucleus, which is consistent with the nuclear localization of Tat. In cotransfection experiments, expression of TBP-1 was able to specifically suppress Tat-mediated transactivation. The strategy described may be useful for direct identification and cloning of genes encoding proteins that associate with other proteins to modulate their activity in a positive or negative fashion.     

Alteration of lymphocyte trafficking by sphingosine-1-phosphate receptor agonists

Blood lymphocyte numbers, essential for the development of efficient immune responses, are maintained by recirculation through secondary lymphoid organs. We show that lymphocyte trafficking is altered by the lysophospholipid sphingosine-1-phosphate (S1P) and by a phosphoryl metabolite of the immunosuppressive agent FTY720. Both species were high-affinity agonists of at least four of the five S1P receptors. These agonists produce lymphopenia in blood and thoracic duct lymph by sequestration of lymphocytes in lymph nodes, but not spleen. S1P receptor agonists induced emptying of lymphoid sinuses by retention of lymphocytes on the abluminal side of sinus-lining endothelium and inhibition of egress into lymph. Inhibition of lymphocyte recirculation by activation of S1P receptors may result in therapeutically useful immunosuppression.     

Analysis of theaflavins and thearubigins from black tea extract by MALDI-TOF mass spectrometry

Black tea contains two major groups of pigments, theaflavins (TFs) and thearubigins (TRs). TFs contain a bis-flavan substituted 1,2-dihydroxy-3,4-benzotropolone moiety. Unlike the TFs, TRs have not yet been characterized. The chemical structure of the TRs remains a mystery. The present paper reports our effort to study the structure of TFs and TRs using delayed pulsed ion extraction of ions generated via the matrix-assisted laser desorption ionization (MALDI) technique, on line with a Linear time-of-flight (TOF) mass spectrometer. Spectra of standard TFs show not only pseudomolecular ions but also ions resulting from fragmentation. The analysis of MALDI-TOF spectra of black tea fractions shows the structure of some TRs, which are similar to those of TFs because the same loss of mass is observed.     

Determination of linuron in potatoes using capillary column gas chromatography/mass spectrometry

A convenient method for the determination of the N-methyl,N-methoxy-phenylurea herbicide (linuron) in potatoes has been developed. The herbicide is extracted from potatoes using a slightly modified Luke multiresidue procedure. The extract is analyzed directly by gas chromatography with cold on-column injection, using an ion trap mass spectrometer in the chemical ionization mode as the detector. Quantitation is performed using p-bromonitrobenzene as the internal standard. The limit of detection is 0.1 ppm. Recoveries of linuron in potatoes averaged 112 +/- 6% at the 0.5 ppm level, and 110 +/- 2% at the 0.2 ppm level. No linuron residues were found in 25 potato samples that were analyzed by this method. Two other N-methyl,N-methoxy-phenylurea herbicides, metobromuron and chlorbromuron, are also sufficiently stable to be determined by this method, but the N,N-dialkyl-phenylurea herbicides neburon, diuron, and monuron are too thermally unstable and degrade in the gas chromatograph.