Antiarrhythmic and Electrophysiological Effects In-vivo of the Major Metabolite of Org 7797 Found in Canine and Rodent Liver Homogenate Preparations

Org 20781, the major metabolite of Org 7797 found in in-vitro experiments was examined for antiarrhythmic and electrophysiological effects in-vivo. Org 20781 (0·5–2·0 mg kg^?1 i.v.) inhibited the development of early ischaemia-induced arrhythmias in rats, suppressed spontaneous ventricular tachycardia (VT) in conscious dogs with 24-h old infarcts, and prevented electrical induction of VT in dogs with 5–6-day old infarcts, actions associated with slowing of conduction at all levels of the myocardium. Cardiac refractory periods were only modestly prolonged whilst repolarization was unchanged. Peak plasma levels of the parent compound (infused to total doses of 2–4mg kg^?1) associated with suppression of late arrhythmias were 6–18 μm, whilst the mean plasma elimination half-life (in normal dogs) was 107 min. It was concluded that the major metabolite has a similar antiarrhythmic and electrophysiological profile to the parent compound, is at least half as potent and may contribute to the therapeutic effects of Org 7797 administration.     

Postpemphigus acanthomata: a sign of clinical activity?

Background Pemphigus is a group of vesiculobullous disorders in which the blisters usually heal with hyper- or hypopigmentation. The appearance of acanthomata at sites of previous blisters has been noted in some cases. Methods All cases of pemphigus admitted to the Madras Medical College hospitals during a 2-year period from March 1993 to March 1995 were taken into the study and screened for the presence of acanthomata. Results Fifty-two cases of pemphigus were identified, 47 of pemphigus vulgaris and five of pemphigus foliaceus; and of these 13 developed acanthomata when the blisters healed. Ten of these cases were of pemphigus vulgaris and three were of pemphigus foliaceus; biopsy of these lesions showed hyperkeratosis, acanthosis, papillomatosis, and intraepidermal clefting. Immunofluorescence carried out in two of these acanthomata also showed intercellular fluorescence. Conclusions The occurrence of acanthomata in healed lesions of pemphigus is not uncommon; because histopathologic and immunofluorescence evidence of disease activity is present, cases of this sort require careful follow-up.     

HELLP Syndrome: an Often Unrecognized Complication of Preeclampsia

We describe a case of preeclampsia with the HELLP (Haemolysis, Elevated Liver enzymes, Low Platelets) syndrome and highlight the delayed diagnosis due to its nonspecific presentation. This syndrome is associated with significant maternal and perinatal mortality and morbidity and we discuss the importance of early recognition of the condition, aggressive management and a multidisciplinary approach.     

Antiarrhythmic activity of 17 beta-aminoestratrienes. Comparison of 3-ols and 3-acetates with the corresponding 3-(3-amino-2-hydroxypropyl) ethers

The antiarrhythmic efficacy of 17 beta-amino- and 17 beta-amino-16 alpha-hydroxyestratrien-3-ols and 3-acetates (group 1) was compared with the efficacy of corresponding 3-[2-hydroxy-3-(isopropylamino)propyl] and 3-[2-hydroxy-3-(tert-butylamino)propyl] ethers (group II), substituents which are usually associated with beta-adrenoceptor blocking activity. Group I compounds exerted potent antiarrhythmic activity against both aconitine-induced arrhythmias in mice and ischemia-induced arrhythmias in rats and reduced the maximum following frequency of isolated guinea pig atria. Electrophysiological studies indicated that their mechanism of action is due to an ability to reduce the fast inward sodium current in cardiac cells (class I antiarrhythmic action). Group II compounds were inactive in the aconitine and atrial tests and electrophysiological studies confirmed that they were devoid of class I activity. However, these compounds, like both class I antiarrhythmic and beta-adrenoceptor blocking drugs, were active against ischemia-induced arrhythmias. Group II compounds, unlike group I compounds, exerted nonspecific beta-adrenoceptor blocking actions, which may account for their activity in the rat test. It was concluded that introduction of the 3-substituted ether group did not confer any advantage over the parent 3-ol or 3-acetate compounds.     

Modulation of vocal and nonvocal behavior in adult squirrel monkeys by selective MAO-A and MAO-B inhibition

The acute effects of monoamine oxidase inhibitors L-deprenyl (0.5-5.0 mg/kg), clorgyline (1.0-10.0 mg/kg), and milacemide (100-400 mg/kg) on the behavior of adult male squirrel monkeys were examined during brief social separations beginning 60 min after subcutaneous drug administration. All three drugs selectively reduced the rate of calling during social separation at doses which did not affect time spent in locomotion, nor the frequency of vigilance-checking. Deprenyl and milacemide, but not clorgyline, produced concurrent decreases in locomotion at the higher doses tested. At threshold doses, clorgyline, but not deprenyl or milacemide, increased call duration and decreased call peak frequency compared to vehicle control values. Plasma levels of MHPG were decreased by an optimal dose of clorgyline but not by deprenyl or milacemide, indicating that substrate specificity was maintained at the drug doses employed. We conclude that different MAO substrates mediate different aspects of vocal and nonvocal behavior in adult male squirrel monkeys.     

Filtration of fentanyl is not the cause of the elevation of arterial blood pressure associated with post-bypass ultrafiltration in children

Modified ultrafiltration after cardiopulmonary bypass in children has been shown to be associated with an increase in arterial blood pressure. As part of a series of studies to investigate the possible causes of this blood pressure elevation, the hypothesis that if filtration was removing a significant amount of fentanyl, then the increase in blood pressure might be due to pain was proposed. Ten children, aged between 0.5 and 9.3 years (median 3.8 years), weighing 5.9 to 25..5 kg (median 15.7 kg), underwent corrective cardiac surgery (incorporating modified ultrafiltration). A standard anesthetic protocol was followed, with up to 78 μg/kg of fentanyl given prebypass for analgesia. After completion of cardiopulmonary bypass, modified ultrafiltration was commenced at 100 mL/min until a hematocrit of 35% was reached. Samples were taken of arterial blood (prefiltration, 3, 10, and 20 minutes postfiltration), the venous reservoir blood (prefiltration) and the filtrate (5 and 10 minutes into filtration). Hemodynamic data were recorded both prefiltration and postfiltration. The hemodynamic data showed the expected rise in both systemic arterial pressure and cardiac index after ultrafiltration. The plasma fentanyl concentrations did not significantly change after ultrafiltration: 1.59 to 12.39 ng/mL (median 6.27 ng/mL) prefiltration and 2.05 to 15.59 ng/mL (6.29 ng/mL) at 3 minutes, 2.22 to 12.64 ng/mL (6.87 ng/mL) at 10 minutes, and 1.83 to 11.52 ng/mL (5.85 ng/mL) at 20 minutes postfiltration. The concentration of fentanyl in the venous reservoir, 2.06 to 11.64 ng/mL (7.04 ng/mL), was not significantly different from the plasma levels. The level of fentanyl in the filtrate was significantly less than the plasma levels, 0.243 to 1.87 ng/mL (0.894 ng/mL) at 5 minutes and 0.385 to 1.688 ng / mL (0.952 ng / mL) at 10 minutes into filtration; (P < 0.02 by the Wilcoxon signed-rank method). The data show that the plasma fentanyl concentration was not significantly reduced by modified ultrafiltration. The fentanyl levels found prefiltration were maintained postfiltration, and the observed changes in systemic arterial pressure were not due to an acute fall in the plasma concentration of analgesic drug.     

Discovery of potent and selective inhibitors of procollagen C-proteinase for the treatment of fibrotic disorders

Introduction   Fibrosis is a component of many tissue pathologies leading to loss of normal tissue function, primarily due to excessive collagen deposition. Collagen is deposited following cleavage of the C- and N- terminal peptides from the pro-collagen molecule. The cleavage of the globular C-peptide by PCP reduces solubility of the fibrillar collagen molecule, resulting in deposition of insoluble collagen. Increased insoluble collagen deposition is a feature of all organ fibroses, with inhibition of this process, a key potential anti-fibrotic mechanism. The aim of this work was to discover potent and selective PCP inhibitors as experimental, topically applied, anti-fibrotic drugs for clinical evaluation.
Materials and methods   PCP was cloned from human osteosarcoma cells and enzymatic activity demonstrated using a PCP-specific peptide cleavage assay. Activities were confirmed by measuring cleavage of [³H]C-peptide from type-I pro-collagen. A cell-based fibroplasias model was employed to demonstrate compound efficacy using collagen deposition, liberated C-peptide and histological endpoints. The activities of PCP inhibitors in fibroblast and epithelial in vitro cell proliferation and migration assays, and selectivity vs. a panel of MMPs were also determined.
Discussion   In summary, we have identified and characterized potent and selective inhibitors of PCP for progression to clinical studies for investigation as a treatment paradigm for fibrotic disease.  

  Results     

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