Small intestinal strangulation in 60 cattle - clinical, laboratory and ultrasonographic findings, treatment and outcome.

BACKGROUND: Intestinal strangulation is constriction of the intestine by a band of tissue, ligament or blood vessel causing partial or complete intestinal obstruction. This retrospective study describes the clinical, laboratory and ultrasonographic findings, treatment and outcome of 60 cows with intestinal strangulation. RESULTS: The general condition was abnormal in all cows (60/60), 23.3% (14/60) had nonspecific signs of pain, 40.0% (24/60) had signs of colic and 48.3% (29/60) had signs of somatic (parietal) pain. The most common digestive tract abnormalities were, in decreasing frequency, reduced or absent intestinal motility (100%, 60/60), reduced or absent faecal output (98.3%, 59/60), reduced or absent rumen motility (93.4%, 56/60), dilated small intestines on transrectal palpation (63.3%, 38/60), positive ballottement and swinging auscultation (BSA) and/or percussion and simultaneous auscultation (PSA) on the right side of the abdomen (58.3%, 35/60) and at least one positive foreign body test, most commonly the back grip, in 33.9% (20/59) of the cows. Other common findings were reduced skin surface temperature (67.8%, 40/59), reduced skin turgor (51.7%, 31/60), prolonged capillary refill time (49.2%, 29/59), enophthalmus (48.3%, 29/60) and moderate to severe scleral injection (46.6%, 27/58). The most common laboratory findings were hypokalaemia (58.3%, 35/60), haemoconcentration (57.6%, 34/59), base excess (51.1%, 24/47), hyperproteinaemia (45.8%, 27/59), hyperbilirubinaemia (43.3%, 26/60), acidosis (42.6%, 20/47) and azotaemia (38.3%, 23/60). The principal ultrasonographic findings were subjectively reduced or absent small intestinal motility and dilated small intestines, but the strangulation could not be visualised by ultrasonography. With one exception, all cows underwent a right flank laparotomy to resolve the strangulation by transection or resection of the impinging tissue. Forty-nine (81.7%) cows were discharged and 11 (18.3%) were euthanized before, during or after surgery. CONCLUSIONS: Without laparotomy, intestinal strangulation could be clinically (transrectally) diagnosed in only 10% of the cows. A laparotomy is therefore essential for the correct diagnosis. The prognosis is good with prompt surgical treatment.

Fragment Screening and Fast Micromolar Detection on a Benchtop NMR Spectrometer Boosted by Photoinduced Hyperpolarization.

Fragment-based drug design is a well-established strategy for rational drug design, with nuclear magnetic resonance (NMR) on high-field spectrometers as the method of reference for screening and hit validation. However, high-field NMR spectrometers are not only expensive, but require specialized maintenance, dedicated space, and depend on liquid helium cooling which became critical over the recurring global helium shortages. We propose an alternative to high-field NMR screening by applying the recently developed approach of fragment screening by photoinduced hyperpolarized NMR on a cryogen-free 80 MHz benchtop NMR spectrometer yielding signal enhancements of up to three orders in magnitude. It is demonstrated that it is possible to discover new hits and kick-off drug design using a benchtop NMR spectrometer at low micromolar concentrations of both protein and ligand. The approach presented performs at higher speed than state-of-the-art high-field NMR approaches while exhibiting a limit of detection in the nanomolar range. Photoinduced hyperpolarization is known to be inexpensive and simple to be implemented, which aligns greatly with the philosophy of benchtop NMR spectrometers. These findings open the way for the use of benchtop NMR in near-physiological conditions for drug design and further life science applications.

Cytotoxic and antibacterial beilschmiedic acids from a Gabonese species of Beilschmiedia.

High-throughput natural products chemistry methods have facilitated the isolation of eight new (1-8) and two known (9 and 10) beilschmiedic acid derivatives from the leaves of a Gabonese species of Beilschmiedia. Compounds 3-10 were isolated in microgram quantities, and the NMR data for structure elucidation and dereplication were acquired utilizing a Bruker BioSpin TCI 1.7 mm MicroCryoProbe. All of the compounds were screened for cytotoxic and antibacterial activity against NCI-H460 human lung cancer cells and a clinical isolate of methicillin-resistant Staphylococcus aureus, respectively. This is the first report of cytotoxic activity for the endiandric/beilschmiedic acid class of compounds.

High-precision heteronuclear 2D NMR experiments using 10-ppm spectral window to resolve carbon overlap.

The acquisition of a complementary heteronuclear 2D NMR experiment with 10-ppm carbon window allows chemists to improve by a factor 20-25 the spectral resolution and determine carbon chemical shifts with five figures from 2D spectra.

Structural biophysics of the NusB:NusE antitermination complex.

In prokaryotic transcription regulation, several host factors form a complex with RNA polymerase and the nascent mRNA. As part of a process known as antitermination, two of these host factors, NusB and NusE, bind to form a heterodimer, which interacts with a specific boxA site on the RNA. The NusB/NusE/boxA RNA ternary complex interacts with the RNA polymerase transcription complex, stabilizing it and allowing transcription past premature termination points. The NusB protein also binds boxA RNA individually and retains all specificity for boxA. However, NusE increases the affinity of RNA to NusB in the ternary complex, which contributes to efficient antitermination. To understand the molecular mechanism of the process, we have determined the structure of NusB from the thermophilic bacterium Aquifex aeolicus and studied the interaction of NusB and NusE. We characterize this binding interaction using NMR, isothermal titration calorimetry, gel filtration, and analytical ultracentrifugation. The binding site of NusE on NusB was determined using NMR chemical shift perturbation studies. We have also determined the NusE binding site in the ternary Escherichia coli NusB/NusE/boxA RNA complex and show that it is very similar to that in the NusB/NusE complex. There is one loop of residues (from 113 to 118 in NusB) affected by NusE binding in the ternary complex but not in the binary complex. This difference may be correlated to an increase in binding affinity of RNA for the NusB/NusE complex.

Amylosin from Bacillus amyloliquefaciens, a K+ and Na+ channel-forming toxic peptide containing a polyene structure.

Bacillus amyloliquefaciens strains isolated from the indoor environment of moisture-damaged buildings produce a 1197 Da toxin, named amylosin. Nuclear magnetic resonance (NMR) data showed that amylosin contains a chromophoric polyene structure and the amino acids leucine/isoleucine, proline, aspartic acid/asparagine, glutamic acid/glutamine and tyrosine. A quantitation method for amylosin was developed using commercially available amphotericin B as a reference compound and a known concentration of amylosin determined by NMR with the electronic reference to access in vivo concentration (ERETIC) method. Purified amylosin inhibited motility of boar sperm cells at an exposure concentration of 135 nM and hyperpolarized their cell membrane and depolarized their mitochondria at exposure to concentration of 33-67 nM for 10 min. In a 3-d exposure time only 27 nM of amylosin was needed to provoke the same toxicity functions. Amylosin was cytotoxic to feline lung cells at concentrations of <170 nM. Purified amylosin provoked adenosine 5'-triphosphate (ATP)-independent cation influx into isolated rat liver mitochondria (RLM), inducing swelling of the mitochondria at concentrations of 200 nM K(+) or >250 nM Na(+) medium. In the K(+)- or Na(+)-containing medium, amylosin uncoupled RLM, causing oxidation of pyridine nucleotides (PN), loss of the mitochondrial membrane potential, and suppressed ATP synthesis. Purified amylosin produced cation channels in black-lipid membranes (BLMs) with a selectivity K(+)>Na(+) at a concentration of 26 nM, i.e. the same concentration at which amylosin was toxic to boar sperm cells. The amylosin cation channels were cholesterol- and ATP-independent and more effective with K(+) than with Na(+). We propose that the toxicity of amylosin may be due its ionophoric properties, representing the first K(+)/Na(+) channel-forming substance reported from B. amyloliquefaciens.

NMR spectroscopic studies on the late onset form of 3-methylglutaconic aciduria type I and other defects in leucine metabolism.

A diagnosis of 3-methylglutaconic aciduria type I (OMIM: 250950) based on elevated urinary excretion of 3-methylglutaconic acid (3MGA), 3-methylglutaric acid (3MG) and 3-hydroxyisovaleric acid (3HIVA) was made in a 61-year-old female patient presenting with leukoencephalopathy slowly progressing over more than 30 years. The diagnosis was confirmed at the enzymatic and molecular level. In vivo brain MR spectroscopic imaging (MRSI) was performed at 3.0 T, and one-dimensional and two-dimensional in vitro NMR spectroscopy of body fluids of the patient was performed at 11.7 T. Additionally, we measured 1D (1)H-NMR spectra of urine of seven patients with a total of four different inborn errors of leucine metabolism. Increased concentrations of 3HIVA, 3MGA (cis and trans) and 3MG were observed in the NMR spectra of the patient's urine. In the cerebrospinal fluid, the 3HIVA concentration was 10 times higher than in the plasma of the patient and only the cis isomer of 3MGA was observed. In vivo brain MRSI showed an abnormal resonance at 1.28 ppm that may be caused by 3HIVA. Comparison of (1)H-NMR spectra of urine samples from all eight patients studied, representing five different inborn errors of leucine metabolism, showed that each disease has typical NMR characteristics. Our leukoencephalopathy patient suffers from a late-onset form of 3-methylglutaconic aciduria type I. In the literature, only very few adult patients with this conditions have been described, and 3HIVA accumulation in white matter in the brain has not been presented before in these patients. Our data demonstrate that (1)H-NMR spectroscopy of urine can easily discriminate between the known inborn errors of leucine metabolism and provide the correct diagnosis.

Coordination chemistry of phosphanyl amino acids: solid state and solution structures of neutral and cationic rhodium complexes.

Copper phosphide or arsenide complexes, [Cu(EPh(2))(neo)] (E = P, As, neo = 2,9-dimethyl-1,10-phenanthroline; trivial name: neocuprine) react selectively with the N-protected brominated serine derivatives, 2-(S)-(alkoxycarbonylamino)-3-bromomethylpropionates ((ROCO)SerBr, : R = PhCH(2), : tBu, : Me) to give the corresponding phosphanylated or arsanylated amino acids, (ROCO)SerPhos (: Phos = PPh(2)) and (Z)SerArs (Ars = AsPh(2), Z = PhCH(2)OCO). The dipeptide (Z)AlaSerPhos was likewise prepared. The phosphanes , and the arsane reacted cleanly with [Rh(2)(micro-Cl)(2)(cod)(2)] to give the rhodium(I) complexes [RhCl(cod)((Z)SerPhos)] , [RhCl(cod)((Boc)SerPhos)] (Boc = tBuOCO), [RhCl(cod)((Z)AlaSerPhos)] , and [RhCl(cod)((Z)SerArs)] which were characterized by X-ray diffraction studies. A common structural feature is an intramolecular (N)H[dot dot dot]Cl(Rh)-hydrogen bridge which according to NMR investigations remains intact in solution. The abstraction of chloride from the coordination sphere of Rh(I) in or has a profound structural impact. While in and , the ligands bind in a monodentate fashion, via the phosphorus atom only, they serve as bidentate ligands via the phosphorus centre and the peptidic C=O group in [Rh(cod)(kappa(2)-(Z)SerPhos)]PF(6) and [Rh(cod)(kappa(2)-(Z)AlaSerPhos)]PF(6). This causes also the amino acid residue structures to change from alpha-helix type in and to a beta-sheet type in both. Addition of chloride to and fully re-establishes the structures of both. The complexes [RhCl(cod)((Z)SerPhos)] and [RhCl(cod)((Boc)SerPhos)] show good activities in homogeneously catalyzed hydrogenations of olefins while the dipeptide complex is less active. Phosphane addition to greatly diminishes the catalytic activity. The cationic complex [Rh(cod)(kappa(2)-(Z)AlaSerPhos)]PF(6) shows low activity which, however, is greatly increased by addition of one equivalent of phosphane.

Dimethyl sulfone in human cerebrospinal fluid and blood plasma confirmed by one-dimensional (1)H and two-dimensional (1)H-(13)C NMR.

(1)H-NMR spectroscopy at 500 MHz was used to confirm that a previously unidentified singlet resonance at 3.14 ppm in the spectra of cerebrospinal fluid and plasma samples corresponds to dimethyl sulfone (DMSO(2)). A triple resonance inverse cryogenic NMR probe, with pre-amplifier and the RF-coils cooled to low temperature, was used to obtain an (1)H-(13)C HSQC spectrum of CSF containing 8 microM (753 ng/ml) DMSO(2). The (1)H-(13)C correlation signal for DMSO(2) was assigned by comparison with the spectrum from an authentic reference sample. In plasma and CSF from healthy controls, the concentration of DMSO(2) ranged between 0 and 25 micromol/l. The concentration of DMSO(2) in plasma from three of four patients with severe methionine adenosyltransferase I/III (MAT I/III) deficiency was about twice the maximum observed for controls. Thus, DMSO(2) occurs as a regular metabolite at low micromolar concentrations in cerebrospinal fluid and plasma. It derives from dietary sources, from intestinal bacterial metabolism and from human endogenous methanethiol metabolism.

Using the diphosphanyl radical as a potential spin label: effect of motion on the EPR spectrum of an R1(R2)P--PR1 radical.

The EPR spectrum of the novel radical Mes*(CH3)P--PMes* (Mes*=2,4,6-(tBu)3C6H2) was measured in the temperature range 100-300 K, and was found to be drastically temperature dependent as a result of the large anisotropy of the 31P hyperfine tensors. Below 180 K, a spectrum of the liquid solution is accurately simulated by calculating the spectral modifications due to slow tumbling of the radical. To achieve this simulation, an algorithm was developed by extending the well-known nitroxide slow-motion simulation technique for the coupling of one electron spin to two nuclear spins. An additional dynamic process responsible for the observed line broadening was found to occur between 180 K and room temperature; this broadening is consistent with an exchange between two conformations. The differences between the isotropic 31P couplings associated with the two conformers are shown to be probably due to an internal rotation about the P--P bond.

Very Stable Phosphiranes.

Zero-valent platinum complexes as precursors for hydrosilylation catalysts have been prepared for the first time with the new BABAR-Phos ligands (the structure of one such complex is depicted). These rather stable phosphiranes can be obtained when the three-membered PC2 ring is incorporated into a polycyclic cage.