Characterization of the enzymatic and nonenzymatic reaction of 13-oxooctadecadienoic acid with glutathione

The enzymatic oxygenation of linoleic acid leads to the production of 13-hydroxyoctadecadienoic acid (13-HODE). Subsequent dehydrogenation of 13-HODE by the NAD(+)-dependent 13-HODE dehydrogenase results in the formation of the 2,4-dienone 13-oxooctadecadienoic acid (13-OXO). These oxidized derivatives of linoleic acid have been shown to be involved in several cellular regulatory processes. In the present study, we have examined the enzymatic and nonenzymatic reaction of 13-OXO with glutathione (GSH) and N-acetylcysteine (N-AcCySH). Nonenzymatic reaction rates were determined spectrophotometrically and exhibited a pH optimum of 9.0 which is consistent with attack of a thiolate anion. Product formation was evaluated by reverse-phase HPLC which showed formation of one major product upon reaction with either GSH or N-AcCySH. The HPLC-purified products were examined by FAB MS as well as one- and two-dimensional NMR. The products, with either GSH or N-AcCySH, were found to consist of an equal mixture of two diastereomers arising from addition of a thiolate to the 9 position of 13-OXO. Using GSH as the thiol, the reaction was also shown to be catalyzed by rat glutathione transferase 8-8. In the case of the enzymatic reaction there is stereoselective product formation. Furthermore, submicromolar concentrations of the 13-OXO-GSH conjugate were shown to significantly inhibit glutathione transferase activity in HT-29 homogenates. These investigations provide insight into the potential metabolic disposition of linoleate oxygenation products.     

Global phylogeography of the ridley sea turtles (Lepidochelys spp.) as inferred from mitochondrial DNA sequences

BACKGROUND: The cardiovascular applications of magnetic resonance (MR) techniques in coronary artery disease have increased considerably in recent years. Technical advantages of MR imaging are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. These characteristics allow the accurate assessment of left ventricular mass and volume, the differentiation of infarcted from normal tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. METHODS: In addition to the conventionally used spin-echo and cine-echo techniques, newer techniques such as myocardial tagging, ultrafast MR imaging and MR coronary angiography have been developed. These newer techniques allow a more accurate assessment of ventricular function (tagging), myocardial perfusion (ultrafast imaging), and evaluation of stenosis severity (MR coronary angiography). Particularly early detection and flow assessment of stenosed coronary arteries and bypasses by MR angiography would constitute a major breakthrough in cardiovascular MR imaging. Apart from the MR imaging techniques, cardiac metabolism may be well assessed using MR spectroscopy. This provides unique information on the metabolic behaviour of the myocardium under conditions stress-induced ischemia. However, the definite niche of cardiac MR spectroscopy has still to be settled. CONCLUSION: Currently, MR techniques allow the evaluation of anatomy and function (accepted use), perfusion and viability (development phase), and coronary angiography (experimental phase). A particular strength of MR imaging is that one single MR test may encompass cardiac anatomy, perfusion, function, metabolism and coronary angiography. The replacement of multiple diagnostic tests with one MR test may have major effects on cardiovascular healthcare economics and would outweight the cost inherent to the MR angiography procedure.     

Treatment of linea alba hernia and diastasis of rectus abdominis

The asynchronous development of structural and metabolic disorders of aponeurosis, leading to the development of defects in sheath of the rectus abdominis is the major factor of hernia of linea alba formation. Development of diastasis of m. rectus abdominis is caused by primary structural and metabolic changes of myocytes caused by the extreme overload. The important factor of the operation is restoration of anatomic and physiologic parameters of the abdominal wall by bringing mm. rectus abdominis together, shortening and enforsing of aponeurosis makes it possible to distribute regularly the load on the aponeurotic sheath of musculi recti.     

Identification of C1 presympathetic neurons in rat rostral ventrolateral medulla by juxtacellular labeling in vivo

The rostral ventrolateral medulla (RVLM) contains barosensitive, bulbospinal neurons that provide the main supraspinal excitatory input to sympathetic vasomotor preganglionic neurons. However, the phenotype of the critical RVLM cells has not been conclusively determined. The goal of the current study was to identify the proportion of electrophysiologically defined, putative, presympathetic RVLM neurons that are C1 cells. We used a juxtacellular labeling technique to individually fill spontaneously active, barosensitive, bulbospinal RVLM neurons with biotinamide following electrophysiological characterization in chloralose-anesthetized rats. To determine whether these neurons could be classified as C1 cells, the biotinamide-labeled cells were processed for detection of tyrosine hydroxylase. The majority of barosensitive bulbospinal RVLM neurons were tyrosine hydroxylase immunoreactive (TH-ir; 28 of 39). All of the barosensitive bulbospinal RVLM neurons with axonal conduction velocities in the C fiber range (<1 m/second) were TH-ir (n = 16), whereas faster conducting cells (1 to 7 m/second) were either lightly TH-ir (n = 12) or not detectably TH-ir (n = 11). Adjacent respiratory-related RVLM units labeled with biotinamide were not detectably TH-ir (n = 10). To verify that TH-ir cells were indeed adrenergic, a subset of barosensitive bulbospinal cells labeled with biotinamide were examined for phenylethanolamine N-methyltransferase immunoreactivity (PNMT-ir). Three slowly conducting cells had detectable PNMT-ir, and two fast-conducting cells had no detectable PNMT-ir. These results indicate that the majority of bulbospinal RVLM neurons with putative sympathoexcitatory function are C1 cells.     

Pregnancy after transfer of embryos which were generated from in-vitro matured oocytes

In-vitro maturation of human oocytes is an important technique in assisted reproduction due to its potential for reducing the use of fertility drugs. We offered this technique as an alternative to cancelling the cycle to a patient who was at risk of ovarian hyperstimulation syndrome (OHSS) after treatment with gonadotrophin-releasing hormone analogue (GnRHa) and human menopausal gonadotrophin (HMG). The patient had 40 visible antral follicles with a maximum diameter of 13 mm and an oestradiol concentration of 14,000 pmol/l on cycle day 12. Immature oocytes were aspirated transvaginally under ultrasound guidance. Ten cumulus-enclosed oocytes were harvested and nine of them completed nuclear maturation to metaphase II after 48 h in culture. By 18 h after an intracytoplasmic sperm injection (ICSI) procedure, seven of these metaphase II stage oocytes displayed two distinct pronuclei and two polar bodies. All fertilized oocytes but one underwent cleaveage; four of these were transferred 2 days later. Endometrial priming was initiated with 8 mg oestradiol valerate daily from the day of oocyte retrieval and 50 mg progesterone was injected i.m. daily starting 2 days after that. A single intrauterine sac was seen containing one fetus with positive fetal heart beat on ultrasound at 7 weeks of gestation. Unfortunately, the pregnancy ended at 24 weeks shortly after premature rupture of membranes; a live healthy-looking girl was delivered who died 18 days later.     

Neurogenic pulmonary edema. Pathogenesis, clinical picture and therapy

Neurogenic pulmonary edema (NPE) is a rare but always life-threatening complication in patients with central nervous system lesions. NPE is evident if patients shortly after cerebral lesions suddenly develop pulmonary edema and other causes of the symptoms, such as aspiration of gastric content, congestive heart failure and direct toxic exposure, are ruled out. METHODS: The current body of literature, partially obtained by computer-guided search (Winspirs) regarding epidemiology, pathophysiology and therapy of NPE was reviewed. Additionally, the case of a patient who developed a sudden pulmonary edema after an episode of tonic-clonic seizures is analyzed. We first provide information about history, definition, incidence and mortality of NPE. Second, a case report of a postictal NPE is presented to illustrate the clinical picture of NPE, and the applied therapeutic strategies are discussed. Third, recent pathophysiologic concepts about symptoms and possible therapeutic principles are reviewed. Fourth, a rational therapeutic plan for the prehospital emergency therapy of NPE is outlined. RESULTS: The different etiologies all have one characteristic feature: an acute emergency which causes increased intracerebral pressure (ICP). NPE is known in patients after cerebral trauma, intracranial hemorrhage, stroke, intracranial tumor or seizures. The incidence is estimated at around 1% after cerebral trauma, at 71% after cerebral hemorrhage and at 2% after seizures. Mortality is appraised to lie between 60 and 100%, independent of etiology. There is a definite pathophysiologic sequence leading to NPE: a central nervous system lesion causes a sudden increase in ICP which triggers an upregulation of sympathetic signal transduction to assure brain perfusion. Increased tonus of venous and arterial vessels and of myocardial function are the immediate consequences. However, if systemic vascular resistance (SVR) increases excessively, left ventricular failure and finally pulmonary edema (NPE) may result. Additionally, the protein-rich edema fluid points to an increased endothelial permeability within the pulmonary circuit. This is thought to be caused by the acute pressure increase and by neurohumoral mechanisms, possibly similar to those described for the systemic inflammatory response syndrome (SIRS). The most important central nervous system structures involved in NPE are the medulla oblongata and the hypothalamus. CONCLUSION: NPE is always a life-threatening symptom after increased ICP, where immediate therapeutic interventions are imperative. A rational therapeutic approach needs to be focused on decreasing ICP as primary goal. Additionally, attempts should be made to optimize body oxygenation, decrease pre- and afterload and increase myocardial contractility. Postictal patients suspicious for incipient ventilation problems must be admitted to hospital for further evaluation.