Effects of cysteinyl-leukotriene receptor antagonist, thromboxane A2 receptor antagonist, and thromboxane A2 synthetase inhibitor on antigen-induced bronchoconstriction in patients with asthma

BACKGROUND: Leukotriene (LT) and thromboxane A2 (TXA2) receptor antagonists have been used in the treatment of asthma. OBJECTIVES: We examined the effects of an LT receptor antagonist, TXA2 receptor antagonist, and TXA2 synthetase inhibitor on bronchoprovocation test (BPT) in patients with mild-to-moderate atopic asthma. METHODS: BPT was performed four times in each of six asthmatics. Development of the immediate asthmatic reaction (IAR) and late asthmatic reaction (LAR) was confirmed on the first BPT (BPT1). After a 7-day washout period, an LT receptor antagonist (pranlukast, 450 mg/d), TXA2 receptor antagonist (seratrodast, 80 mg/d), or TXA2 synthetase inhibitor (ozagrel, 800 mg/d) was administered orally over 7 days at random using a cross-over method (BPT2-4). Blood levels of LTB4, LTC4, LTD4, 11-dehydrothromboxane B2, eosinophil cationic protein, and histamine were measured at reaction phases of pre-BPT, IAR, and LAR. RESULTS: Administration of pranlukast suppressed IAR by 80.5% (p < 0.0001) and LAR by 54.6% (p = 0.0391). Ozagrel significantly suppressed IAR by 39.5% (p = 0.0413), but the fall in FEV1 was >20% (21.56+/-4.173%). Seratrodast did not suppress IAR or LAR. Blood levels of chemical mediators did not correlate with the suppressive effects of the tested drugs. CONCLUSIONS: The LT receptor antagonist was considered to be the most effective. LT might play a more important role in the pathogenesis of asthma than TXA2. Our data showed that measurement of blood levels of chemical mediators is not useful in identifying the pathogenic mechanisms of asthma.     

Effect of DP-1904, a thromboxane A2 synthase inhibitor, on passive Heymann nephritis in rats

Despite the fact that aneuploidy is a major genetic cause of human morbidity and mortality, antimutagenicity studies have used predominantly short-term tests that detect gene mutations, chromosomal aberrations, and micronuclei. Therefore, the major deficiency in the use of short-term tests for antimutagenicity studies is those that detect chromosomal malsegregation leading to aneuploidy. Thus, we initiated a study on the utility of short-term tests for the detection of antianeugenic activity. We selected strain D61.M of Saccharomyces cerevisiae, nocodazole, and chlorophyllin as a model short-term test, aneugen, and antimutagen, respectively, for our initial study. Chlorophyllin strongly inhibited the aneugenic activity of nocodazole, but had no effect on the endpoints when tested alone, in strain D61.M. To our knowledge, this is the first report of an antianeugen. Furthermore, we conclude that strain D61.M can be used as a relatively simple, inexpensive, and rapid short-term test for the study of antianeugenicity.     

A thromboxane A2 synthetase inhibitor as an anticoagulant for left ventricular assist devices

A comparative study to establish more adequate anticoagulation therapy for left ventricular assist devices was done by administering various anticoagulants: heparin, argatroban (a pure thrombin inhibitor), a thromboxane A2 synthetase inhibitor, and protease inhibitor. Results of the investigation revealed that use of no anticoagulation activates the intrinsic pathway of blood coagulation and causes severe coagulopathy, heparin or argatroban causes bleeding tendency, and a thromboxane A2 synthetase inhibitor can maintain blood coagulation within the acceptable range, but not completely. Combined administration of a thromboxane A2 synthetase inhibitor and protease inhibitor was found to be the best anticoagulation therapy in this study.     

Effects of pretreatment with SDZ MRL 953, a novel immunostimulatory lipid A analog, on endotoxin-induced acute lung injury in guinea pigs

SDZ MRL 953 (SDZ), a novel immunostimulatory lipid A analog, has been reported to have immunopharmacological activities similar to those of lipopolysaccharide (LPS) but to have little of the toxicity of LPS. We investigated the effects of pretreatment with SDZ on Escherichia coli endotoxin-induced acute lung injury in guinea pigs. Four experimental groups consisted of saline control (n = 16), SDZ (-12 h) plus LPS (2 mg/kg of SDZ per kg of body weight injected intravenously 12 h before intravenous injection of 2 mg of LPS per kg; n = 15), SDZ (-10 min) plus LPS (SDZ injected 10 min before LPS injection; n = 10), and LPS alone (n = 16). The animals were sacrificed, and lung tissue was sampled 4 h after LPS or saline infusion. Lung injury was assessed by measuring the wet weight-to-dry weight ratio and the level of 125I-labeled albumin accumulation in bronchoalveolar lavage fluid relative to that in plasma. In the SDZ (-12 h) plus LPS group, these two parameters of acute lung injury were decreased compared with those in the LPS alone group. However, they were not decreased in the SDZ (-10 min) plus LPS group. We conclude that SDZ attenuates endotoxin-induced acute lung injury when it is administered 12 h before LPS injection. The attenuating effects of SDZ are speculated to be due to down regulation of the response to endotoxin rather than to receptor blocking.     

In vivo characterization of T-794, a novel reversible inhibitor of monoamine oxidase-A, as an antidepressant with a wide safety margin

T-794 is a new reversible inhibitor of MAO type A. In order to predict its clinical utility as an antidepressant, we examined its pharmacological profile (i.e., MAO inhibitory activity, antidepressant-like activity and safety) in vivo in rodents. The p.o. administration of T-794 potentiated L-5-hydroxytryptophan-induced symptoms with ED50 = 1.01 mg/kg (mice) or 1.15 mg/kg (rats), and L-dopa-induced behavior with ED50 = 5.90 mg/kg (mice), whereas it did not alter the effect of beta-phenylethylamine even at 100 mg/kg (mice). In the L-5-hydroxytryptophan test in rats, the activity of T-794 (at twice the dose of ED50) disappeared by 8 h; the duration of action was similar to that of moclobemide. These results confirm the previous biochemical results that MAO-A inhibition by T-794 is highly selective and of short duration. T-794 was effective in three animal models of depression: reserpine reversal (mice, rats), behavioral despair test (mice) and learned helplessness (rats). In these tests, it had potency similar to or greater than moclobemide, tranylcypromine or imipramine. The p.o. administration of T-794 (30 mg/kg) did not affect the pressor effect of tyramine in anesthetized rats, whereas moclobemide (30 mg/kg) and tranylcypromine (6 mg/kg) potentiated the effect. Acute toxicity of T-794 proved to be very low (maximal tolerated dose > 2 g/kg p.o.) in contrast to brofaromine (maximal tolerated dose = 150 mg/kg p.o.). Unlike tricyclic antidepressants, T-794 did not prevent the oxotremorine-induced tremor even at 100 mg/kg p.o.; in this it demonstrated a lack of the anticholinergic activity. These results suggest that T-794 is an effective and particularly safe antidepressant and that it may make an important contribution in the treatment of depressive disorders.     

A carbocyclic nucleoside analogue is a TNF-alpha inhibitor with immunosuppressive action: role of prostaglandin E2 and protein kinase C and comparison with pentoxifylline

PURPOSE: To compare the activity of topical 0.05% and 0.01% mequitazine versus vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test with allergens. METHODS: Forty subjects with a history of grass pollen allergic conjunctivitis were enrolled in this comparative, randomized, double-masked study. Fifteen minutes before the conjunctival provocation test, subjects received one instillation alone of 0.05% mequitazine eyedrops in one eye and in the fellow eye either one drop of 0.01% dose or vehicle, at the same dosage. Then a specific conjunctival provocation test (CPT) was performed with the allergen threshold concentration previously defined. The therapeutic efficacy was assessed by the decrease in a symptomatic composite score representing the allergic reaction. RESULTS: Topical mequitazine at the dose of 0.05% significantly decreases the intensity of the allergic reaction compared to vehicle. Moreover, the group treated with this dose needed a higher allergen concentration to trigger ocular signs. The 0.01% dose appears efficient only on itching, compared to vehicle. CONCLUSION: The results of this study support the efficacy and the onset of action of 0.05% mequitazine eyedrops versus 0.01% or vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test.     

Sebaceous gland hyperplasia as a side effect of cyclosporin A. Treatment with the CO2 laser

HISTORY AND CLINICAL FINDINGS: After renal transplantation 11 years previously followed by immunosuppression with cyclosporin A, a 59-year-old man developed, shortly after starting the medication, skin-coloured nodules in the region of both ears and the forehead. In the subsequent years the skin changes spread throughout the entire face. The nodes (up to 2 cm in diameter) and nodules were soft and yellowish-white in colour. In addition there were numerous distinct telangiectasias over the whole face. INVESTIGATIONS: Several skin biopsies were taken. They showed largely unremarkable epidermis but marked enlargement and multiplication of the sebaceous glands. DIAGNOSIS, TREATMENT AND COURSE: In view of the histological findings the diagnosis of sebaceous hyperplasia was established. After a trial with carbon dioxide laser, treatment over the entire surface of the two auricles was undertaken under full anaesthesia. The normal auricular contour was reconstituted by removal of the papules and nodes, without any scar formation. CONCLUSION: In the absence of an alternative medication and if the very marked skin changes show no sign of regression, "shaving off" by scalpel of the nodes and nodules or conventional surgery has been the available treatment. However, removal by carbon dioxide laser has the advantage of fewer side effect, is less stressful to the patient and provides a dry operative field.     

The body as a source of self-esteem: The effect of mortality salience on identification with one's body, interest in sex, and appearance monitoring.

The present research investigated the role of the physical body as a source of self-esteem and tested the hypothesis derived from terror management theory that reminding people of their mortality increases self-esteem striving in the form of identification with one's body, interest in sex, and appearance monitoring. The results revealed that individuals high in body esteem responded to mortality salience manipulations with increased identification with their physical bodies in Study 1 and with increased interest in sex in Study 2. Study 3 showed that reminders of death led to decreased appearance monitoring among appearance-oriented participants who were low in body esteem. These findings provide insight into why people often go to extreme lengths to meet cultural standards for the body and its appearance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of bisphosphonates (HEBP, CL2MBP) on the process of biological mineralization in fresh bone and bone tissue de novo as a result of experimental osteogenesis induction in guinea pigs

It is known from the literature that bisphosphonates inhibit mineralization process in skeletal tissues. To study in vivo the effects of HEBP (etidronate) and Cl2MBP (clodronate) both on preexisting bone mineral as well as on the early stages of the mineralization process the experimental model of heterotopical bone induction was chosen. Urinary bladder mucosa was used as an inductor of osteogenesis. Using this model it is possible to compare the effects of bisphosphonates on preexisting mineral on ortothopic bones as well as on the early stages of mineral deposition in the newly formed bone induced in heterotopic sites. HEBP and Cl2MBP doesn't inhibit heterotopic bone induction, but HEBP deeply inhibits the mineralization process; the small amount of deposited mineral does not contain crystalline fraction.     

Extending the margin of safety of preservation period for resuscitation of ischemically damaged pancreas during preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C with thromboxane A2 synthesis inhibitor OKY046

We have shown that 5-hr preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C allows ATP synthesis and makes it possible to resuscitate a canine pancreas subjected to 90 min of warm ischemia. However, 8 hr of preservation using this method caused a disturbance of vascular microcirculation and did not resuscitate the grafts. The aim of this study was to examine the effect of thromboxane A2 synthesis inhibitor OKY046 on vascular endothelial cells and ATP tissue levels of canine pancreas during preservation using the two-layer (University of Wisconsin solution/perfluorochemical) method at 20 degrees C, and vascular microcirculation and pancreas viability after transplantation. Graft viability was judged by graft survival following autotransplantation. ATP tissue levels were measured by high-performance liquid chromatography at the end of preservation. Viability of the vascular endothelial cells was judged using nuclear trypan blue uptake of the graft after preservation. Pancreatic tissue perfusion was measured using an H2 clearance technique after reperfusion. Pancreas grafts subjected to 90 min of warm ischemia were not viable (0/5). However, 5-hr preservation made it possible to recover the pancreas (5/5); 8-hr preservation was not successful (0/3). ATP tissue levels after 5-hr and 8-hr preservation were 9.40+/-2.09 and 7.37+/-1.06 micromol/g dry weight, respectively, and OKY046 did not affect ATP synthesis during 8-hr preservation (8.44+/-0.92 micromol/g dry weight). The percentage of nuclear trypan blue uptake of endothelial cells in 8-hr-preserved grafts was 37.6+/-11.6% and was significantly higher than the value in 5-hr-preserved grafts (5.0+/-3.0%; P<0.01). However, OKY046 significantly reduced trypan blue uptake in 8-hr-preserved grafts (8.2+/-3.6%; P<0.01). Pancreatic tissue perfusion in 8-hr-preserved grafts after 2 hr of reperfusion was 28.5+/-7.5 ml/min/100 g, and was significantly lower than the value in 5-hr-preserved grafts (57.1+/-4.4 ml/ min/100 g; P<0.01), but OKY046 dramatically improved pancreatic tissue perfusion (97.1+/-14.6 ml/min/100 g; P<0.01). As a consequence, 8-hr-preserved grafts were resuscitated (4/5). We conclude that OKY046 protects the vascular endothelium during preservation by the two-layer method at 20 degrees C and consequently improves vascular microcirculation on reperfusion. Together with ATP synthesis, which is essential for repairing damaged cells, the canine pancreas graft subjected to 90 min of warm ischemia is resuscitated during 8-hr preservation by the two-layer method at 20 degrees C. This method holds promise for pancreas-kidney transplantation from cardiac arrest donors.     

Design and synthesis of a series of 6-substituted-2-pyridinylmethylamine derivatives as novel, high-affinity, selective agonists at 5-HT1A receptors

A search for novel, selective agonists with high intrinsic activity at the 5-HT1A subtype of serotonin (5-HT) receptors was undertaken. Mechanistic and thermodynamic considerations led to the design of 6-substituted-2-pyridinylmethylamine as a potential 5-HT1A pharmacophore. Various adducts derived from the 6-substituted-2-pyridinylmethylamine moiety were tested for their affinity at 5-HT1A, alpha1-adrenergic, and D2-dopaminergic receptors. Compounds with high affinity for 5-HT1A receptors (pKi >/= 8) were examined for agonist properties by measuring their ability to inhibit forskolin-stimulated cAMP production in HA7 cells (i.e., HeLa cells permanently transfected with the h5-HT1A receptor gene and expressing the h5-HT1A receptor protein). Several compounds of the type aryl?4-[(6-substituted-pyridin-2-ylmethylamino)methyl]piperidin -1-yl? methanone had nanomolar affinity for 5-HT1A binding sites and were more than 500-fold selective with respect to alpha1 and D2 sites. Importantly, their 5-HT1A agonist properties were demonstrated in HA7 cells where they behaved as potent inhibitors of cAMP accumulation. In particular, (3, 4-dichlorophenyl)?4-[(6-oxazol-5-ylpyridin-2-ylmethylamin o)methyl]pip eridin-1-yl?methanone (70) and (3, 4-dichlorophenyl)?4-[(6-azetidinopyridin-2-ylmethylamino)met hyl]piper idin-1-yl?methanone (36) appeared to be more potent than, and at least as efficacious as, the prototypical 5-HT1A agonist (+/-)-8-OH-DPAT. SAR studies revealed that the pyridine nitrogen atom and the nature and the position of the substituents on the pyridine ring were critically involved in the ability of the compounds to recognize and activate 5-HT1A receptors. Structural modifications of the nonpharmacophoric part of the molecule showed, however, that the entire structure was required for affinity at 5-HT1A binding sites.     

A randomized, placebo-controlled study of oral cimetidine as an immunopotentiator of parenteral immunization with a group B meningococcal vaccine

Cimetidine (CIM) is an H2-receptor antagonist with a long history of clinical use in peptic ulcer disease. In addition to its inhibitory effect upon gastric acid secretion, CIM can also block histamine-mediated immunosuppression by inhibiting H2 receptors on suppressor T cells. CIM results in immunoaugmentation of both cellular and humoral immunity by this mechanism and has been used clinically in the treatment of chronic infectious and neoplastic diseases. We postulated that orally administered CIM, like an adjuvant, could augment the immunologic response to a parenteral vaccine. To test this hypothesis, a randomized placebo (PLB)-controlled, double-blinded study in 14 healthy volunteers was performed using a Group B meningococcal outer membrane protein (OMP) vaccine administered twice, 6 weeks apart. Volunteers were randomized within pairs defined by their screening OMP antibody titers to receive either CIM or PLB which was administered for 5 days, beginning 2 days before each of the two immunizations. All 14 volunteers completed the study with excellent compliance. Sera were tested for anti-OMP and bactericidal antibodies. The groups were comparable in terms of gender distribution, age and baseline anti-OMP titers. Reactogenicity to the vaccine was mild and comparable between groups. There was little effect of CIM (over PLB) on anti-OMP or functional bactericidal antibody levels over time. Geometric means of maximum OMP antibody increase over baseline was 3.3-fold (95% CI: 1.8-6.3) for CIM and 2.4 for PLB (CI: 1.6-3.7). CIM had a corresponding 3.9-fold increase (CI: 1.9-8.3) in bactericidal antibody level compared to 2.2 for PLB (CI: 1.4-3.4). We conclude that oral CIM was not effective as an immunopotentiator of immunization with this group B meningococcal vaccine.     

Design, synthesis, and biological evaluation of a second generation of pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidines as potent and selective A2A adenosine receptor antagonists

New A2A adenosine receptor antagonists in the series of pyrazolo[4, 3-e]-1,2,4-triazolo[1,5-c]pyrimidines, bearing oxygenated substituents on the phenylalkyl chains on the 7-position, have been synthesized. The compounds were tested in binding and functional assays to evaluate affinity, potency, and selectivity for rat A2A compared to rat A1 and human A3 receptor subtypes. The most interesting compounds (5d,e,h) were tested also in binding to human A1 and A2A adenosine receptors. They showed very good affinity (Ki = 0.94 nM for compound 5h) and interesting selectivity with respect to both rA1 and hA3 (compound 5h: rA1/rA2A = 787, hA3/rA2A > 10 000). These important findings make this new series of compounds the first really selective for A2A adenosine receptors. Thermodynamic parameters were evaluated; all the tested compounds displayed an enthalpy-driven binding as expected for antagonists. Moreover, compound 5h showed a negative entropy value. The highly negative enthalpic and entropic contributions could mean that 5h fits very well in the binding site where, probably, an electrostatic interaction is present associated to a scarce solvent reorganization around the receptor binding site. These compounds deserve to be further developed to assess their potential for treatment of neurodegenerative disorders such as Parkinson's disease.     

A new monoclonal antibody, mAb 4A12, identifies a role for the glycosaminoglycan (GAG) binding domain of RANTES in the antiviral effect against HIV-1 and intracellular Ca2+ signaling

The beta-chemokine RANTES (regulated on activation, normal T cell expressed and secreted) suppresses the infection of susceptible host cells by macrophage tropic strains of HIV-1. This effect is attributed to interactions of this chemokine with a 7-transmembrane domain receptor, CCR5, that is required for virus-cell fusion and entry. Here we identify domains of RANTES that contribute to its biological activities through structure-function studies using a new monoclonal antibody, mAb 4A12, isolated from mice immunized with recombinant human RANTES. This monoclonal antibody (mAb) blocked the antiviral activity of RANTES in infectivity assays with HIV-1Bal, and inhibited the mobilization of intracellular Ca2+ elicited by RANTES, yet recognized this chemokine bound to cell surfaces. Epitope mapping using limited proteolysis, reversed phase high-performance liquid chromatography, and mass spectrometry suggest that residues 55-66 of RANTES, which include the COOH-terminal alpha-helical region implicated as the glycosaminoglycan (GAG) binding domain, overlap the determinant recognized by mAb 4A12. This is supported by affinity chromatography studies, which showed that RANTES could be eluted specifically by heparin from a mAb 4A12 immunoaffinity matrix. Removal of cell surface GAGs by enzymatic digestion greatly reduced the ability of mAb 4A12 to detect RANTES passively bound on cell surfaces and abrogated the ability of RANTES to elicit an intracellular Ca2+ signal. Taken together, these studies demonstrate that the COOH-terminal alpha-helical region of RANTES plays a key role in GAG-binding, antiviral activity, and intracellular Ca2+ signaling and support a model in which GAGs play a key role in the biological activities of this chemokine.     

The STOP-NIDDM Trial: an international study on the efficacy of an alpha-glucosidase inhibitor to prevent type 2 diabetes in a population with impaired glucose tolerance: rationale, design, and preliminary screening data. Study to Prevent Non-Insulin-Dependent Diabetes Mellitus

OBJECTIVE: To describe the rationale and design, and to discuss the preliminary screening data, of the Study to Prevent NIDDM (STOP-NIDDM Trial), an international study on the efficacy of the alpha-glucosidase inhibitor acarbose in preventing or delaying the development of type 2 diabetes in a population with impaired glucose tolerance (IGT). RESEARCH DESIGN AND METHODS: A total of 1,418 subjects diagnosed with IGT according to the World Health Organization's criteria and having a fasting plasma glucose concentration > or =5.6 mmol/L were randomized in a double-blind fashion to receive either acarbose (100 mg t.i.d.) or placebo for a predictive median follow-up period of 3.9 years. The primary outcome is the development of type 2 diabetes diagnosed using a 75-g oral glucose tolerance test according to the new criteria. The secondary outcomes are changes in blood pressure, lipid profile, insulin sensitivity, cardiovascular events, and morphometric profile. RESULTS: Screening was performed in a high-risk population. As of 1 March 1997, 4,424 subjects had been screened, and data were available for 3,919 (88.5%) subjects. Of these subjects, 1,200 (30.6%) had glucose intolerance. Of the subjects with glucose intolerance, 521 (13.3%) had previously undetected type 2 diabetes, and 679 (17.3%) had IGT. Of the IGT population, 412 (60.7%) subjects were eligible for the study This population had the following characteristics: the mean age was 54.8 years, 52% of the subjects were female, 53% had more than one risk factor for type 2 diabetes, >90% had a family history of diabetes, 78.2% had a BMI > or =27 kg/m2, 47.5% had high blood pressure, 51.2% had dyslipidemia, and 22.8% of the women had a history of gestational diabetes. CONCLUSIONS: Screening of a high-risk population yields one eligible subject per every 10 volunteers screened. This study should definitely answer the question of whether acarbose can prevent or delay the progression of IGT to type 2 diabetes mellitus.