Influence of indomethacin on the haemodynamic effects of lipopolysaccharide in rats

Summary— This study was undertaken to evaluate the influence of the cyclooxygenase inhibitor indomethacin on the time course of the haemodynamic effects of lipopolysaccharide (LPS) intravenous infusion (10 mg·kg⁻¹·h⁻¹) in anaesthetized rats. LPS infusion produced a rapid (within 10 min) and prolonged (over the 90 min observation period) fall in mean arterial blood pressure (MABP) and a decrease in the pressor responses to noradrenaline (NA, 0.1, 0.3 and 1 μg·kg⁻¹, intravenously [iv]) elicited 60 and 90 min after the onset of LPS infusion. Indomethacin (7 mg·kg⁻¹ iv 30 min prior to the onset of saline or LPS infusion), which by itself did not affect basal MABP nor reactivity to NA in control rats, significantly attenuated the fall in MABP observed within 20 min after the onset of LPS infusion (but did not significantly modify the hypotension observed between 30 and 90 min). Indomethacin also completely prevented the hyporeactivity to NA observed 60 min after the onset of LPS infusion, but it did so only partially at 90 min. Aortic rings removed from LPS or LPS + indomethacin-treated rats showed an identical profile of contractile reactivity (hyporesponsiveness to NA, relaxation to L-arginine, and restoration of the contractile response by methylene blue). These results suggest that in this model, cyclooxygenase products are involved in the early haemodynamic effects of LPS. However, they do not seem to play an obligatory role in the onset of longer term haemodynamic changes.     

Red Cell Membrane Lipid Peroxidation and Hemolysis Secondary to Phototherapy

ABSTRACT. The exposure of red cells to phototherapy light in the presence of a sensitizer (bilirubin) resulted in oxidative injury to the red cell membrane as manifested by a significant increase in the concentration of the products of lipid peroxidation (TBA reactants and diene conjugation) in the membrane and hemolysis. To induce a photo-oxidized membrane injury, the sensitizer (bilirubin) has to be membrane bound. Thus, by altering the availability of free bilirubin in the red cell suspension through changes in the molar concentration ratio of bilirubin to albumin, one is able to regulate the occurrence and extent of the oxidative red cell membrane injury. The clinical implications of these findings are discussed.     

Polyurethane Sheath Disintegration Causing Impaction of Pacer Lead and Shock during Attempted Removal

Steady traction to remove a lead whose polyurethane sheath had disintegrated caused displacement of the heart and caused hypotension; the bared lead uncoiled and impacted in the wall of the subclavian vein. The tension on the intrathoracic lead was relieved via immediate anterior thoracotomy and compartmentalization of the superior vena cava.     

Electromyographic activity of human masticatory muscles in normal young people. Statistical evaluation of reference values for clinical applications

Electromyographic activity of anterior temporal and masseter muscles was measured in 92 young healthy men and women with sound dentitions during rest position, contact in centric occlusion and clench. Male and female mean potentials were similar except in clench, where males had higher electromyographic levels. Mean pooled electromyographic potentials were 1.9 μV (TA) and 1.4 μV (MM) during rest position, 6.5 μV (TA) and 2.8μV (MM) during contact in centric occlusion. Mean maximum voluntary clench potentials were 181.9μV (TA) and 216.2 μV (MM) in men, 161.7 μV (TA) and 156.8 μV (MM) in women. Examined muscles were more asymmetric at low electromyographic activity (rest and centric occlusion) with the temporal muscle less asymmetrical than the masseter. In females temporal muscle activity tended to dominate at every contraction level, while in males masseter activity was stronger in clench, and temporal activity in centric occlusion and in rest position.     

IgA red cell autoantibodies and autoimmune hemolysis

BACKGROUND: The objective of the study was to examine the interrelationships and clinical significance of IgA red cell antibodies in the autoimmune response. STUDY DESIGN AND METHODS: The records of 5235 patients referred to an immunohematology center over a 14-year period were critically examined for patients who had IgA autoantibodies, defined as elutable IgA immunoglobulins that would rebind to normal cells. RESULTS: One hundred twenty-four patients (61 male) aged 6 to 98 years had warm-reacting IgA autoantibodies. In 75 individuals, these were idiopathic; neoplasms were the most common associated conditions in the individuals with secondary IgA autoantibodies. IgA was the only immunoglobulin present in 6 patients; all others also had IgG and/or IgM coating their cells, and 102 individuals also had increased amounts of cell-bound complement. In a comparison by chi-square test of populations with haptoglobins of < 0.1 g per L, IgA was shown to act synergistically with IgG in producing hemolysis (p < 0.01). CONCLUSION: Autoimmune hemolysis due to IgA antibodies alone in rare, with red cell destruction occurring through mechanisms similar to those for IgG. Most commonly, IgA acts synergistically with other immunoglobulins (usually IgG) and complement; the hemolysis may be severe. Whether IgA autoantibodies alone can activate complement remains controversial, but increasing evidence suggests that they can, possibly via the alternative pathway, and that this activation may result in intravascular hemolysis.     

Pacemaker Diagnostics:

POLLAK, W.M., et al .: Pacemaker Diagnostics: A Critical Appraisal of Current Technology. Diagnostic information retrieved from a pacemaker offers the ability to improve patient care. Pacemaker diagnostic data provides information regarding pacemaker function and activity, lead function, arrhythmia occurrence, and data to aid in optimal pacemaker programming. Current pacemakers incorporate greater storage capabilities, more efficient means of storing and presenting data between follow-up visits, and more options for programming diagnostic functions and algorithms. The cardiac rhythm of the paced patient can be evaluated via real-time intracardiac electrograms at interrogation, surface electrocardiograms, ambulatory electrocardiograms, and by pacemaker stored diagnostic function that may include stored intracardiac electrograms. This article focuses on the various methods of obtaining diagnostic information regarding pacemaker activity, pacemaker function, and diagnostic information on cardiac arrhythmias. The current clinical applicability and limitations of these methods and the use of stored diagnostic data in the clinical follow-up and study of patients with pacemakers is discussed. (PACE 2003; 26[Pt. I]:76–98)