Synthesis of amides with anti-inflammatory and analgesic activities

A series of N-Aroyl-cyclohexyl- and cyclohexenylamides 3- or 4-methylsubstituted were synthesized and evaluated for their anti-inflammatory and analgesic potencies, and gastrointestinal irritation liability. One compound, N-benzoyl-4-methyl-cyclohexylamide 6a, possessed an anti-inflammatory activity comparable to that of indomethacin.

Ceramide glycanase from rat mammary tissues: inhibition by PPMP(D-/L-) and its probable role in signal transduction

A ceramide glycanase (CGase activity has been characterized from lactating rat mammary tissue which cleaves the glycosidic bond between sphingosine and the glucose chain of a glycosphingolipid (GSL) thus liberating the intact oligosaccharide chain from a GSL. The majority (65%) of the hydrolase activity was detected in the supernatant fraction when the rat mammary tissue homogenate was centrifuged at 100,000 x g. Attempts to purify the enzyme indicated that the CGase protein is of hydrophobic nature as it binds to hydrophobic columns. The enzyme has been partially purified using hydrophobic columns in tandem. The partially purified protein was found to be immunoreactive to the antibody raised against the purified clam CGase. The immunostained band corresponded to a 64 kDa protein as also found with the clam enzyme. This immuno cross-reactivity indicated probable structural similarities between CGase proteins isolated from widely separated species in the evolutionary tree. The rat CGase was found to have a specific detergent requirement for optimal activity, and the pH optimum was found to be between 5 and 6. The enzyme activity is partially heat stable. It is not a divalent cation requiring enzyme; however, the activity is totally inhibited in the presence of mercury, indicative of a sulfhydryl group in the active site of the enzyme. The rat mammary CGase activity is inhibited in the presence of both D- and L-PPMP (1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol. HCl), homologs of PDMP (1-phenyl-2-decanoylamino-3-morpholino-1-propanol. HCl), a well-known inhibitor of GlcT-1 (Ceramide: UDP-Glc Glucosyltransferase), an enzyme in the glycolipid synthetic pathway. The inhibition seems to be of a competitive nature and the same type of inhibition is also observed with clam CGase. The CGase activity was found to be highest in lactating tissue compared to the activity found in either pregnant or post-lactating rat mammary tissues. Tissue survey indicated the presence of high levels of CGase in lactating rat liver, uterus, and ovary; moderate activity was detected in kidney and spleen. Both virgin and male rat mammary tissue also indicated a basic level of CGase activity. However, newborn spleen and mammary tissue showed a comparable level of activity to that found in lactating rat tissues. This report is mainly concerned with the characterization of CGase activity from a mammalian source and its importance in cellular processes.

Transglutaminase-synthesized spermine derivative of substance P recognizes rat portal vein neurokinin-3 receptors

The effects of the transglutaminase-synthesized polyamine derivatives of Substance P (SP) have been further characterized by their ability to contract in vitro the rat portal vein strip (RPV), a pharmacological preparation particularly rich in NK-3 receptors. The effects of selective agonists of NK-1, NK-2 and NK-3 receptors [Sar9,Met(O(2))11]SP, beta-Ala8 NKA(4-10), and senktide respectively, were also evaluated by measuring RPV concentration-response curves. Peptide [GR-82334 (NK-1) and MEN-10,376 (NK-2)] and nonpeptide [WIN 51,708 (NK-1) and SR 142801 (NK-3)] NK receptor antagonists were used to confirm the participation of the different NK receptors to contractile response. Our results demonstrated that the spermine derivative of SP (Spm-SP), previously shown to be unable to recognize NK-1 and NK-2 receptors in some bioassays, contracts RPV (EC50 = 588 nM) better than the native neuropeptide (EC50 = 1120 nM). A pretreatment with thiorphan, an inhibitor of neutral endopeptidases, significantly reduced such a difference. While this inhibitor shifts the SP concentration-response curves to the left (EC50 = 720 nM) the action of Spm-SP and [Sar9,Met(O(2))11]SP were completely thiorphan-resistant. In the absence of thiorphan we found the following rank order of potency: senktide > > beta-Ala8 NKA(4-10) > [Sar9,Met(O(2))11]SP = Spm-SP > SP. Among the mentioned NK receptor antagonists, only the selective NK-3 receptor antagonist, SR 142801, shifted to the right Spm-SP and [Sar9,Met(O(2))11]SP concentration-response curve, showing pKB values of 5.84 and 5.88, respectively. Therefore, the reported results suggest that the introduction of a Spm moiety into the SP alters the parent peptide molecule by increasing its affinity for NK-3 receptors and/or by preventing its degradation by some proteolytic enzymes.

Effects of hyperbaric oxygen exposure on non-adrenergic non-cholinergic responses of rat trachea

The effects of prolonged (20 day) hyperbaric exposure (HBO) to oxygen on non adrenergic non cholinergic (NANC) contractile and relaxant responses of rat trachea were examined. The electrical field stimulation (EFS) of rat tracheal rings was performed at 30 Hz and contractile and relaxant responses were assessed in the absence or in the presence of pretreatment with L-nitro-arginine-methyl-ester (L-NAME), an inhibitor of NO synthase, and L-Arginine (L-ARG), a precursor of NO synthesis, plus L-NAME. Our data demonstrated that L-NAME significantly (p < 0.05) enhanced the contractile responses induced by EFS (controls 30.6 +/- 0.99%; L-NAME 76.07 +/- 2.00%) and statistically (p < 0.05) reduced the relaxant component of EFS (controls 31.10 +/- 0.46; L-NAME 15.00 +/- 0.12); these effects were reversed when tissues were pretreated with L-ARG plus L-NAME, suggesting that NO plays a modulatory role in cholinergic neurotransmission and participates in EFS relaxant responses. Moreover, prolonged HBO exposure (20 days) at 202.6 and 303.9 kPa did not modify the contractile or relaxant responses induced by EFS, nor modify the L-NAME or L-ARG effects on EFS responses.

Reciprocal trophic interactions between climbing fibres and Purkinje cells in the rat cerebellum

In the adult cerebellum both the climbing fibre arbour and the Purkinje cell are very plastic and each element is able to exert a remarkable action on the other one. The adult phenotype of the Purkinje cell is strictly dependent on the presence of its climbing fibre arbour. When the climbing fibre is missing, the Purkinje cell undergoes a hyperspiny transformation and becomes hyperinnervated by the parallel fibres. However, this change is fully reversible. The climbing fibre-deprived Purkinje cell is able to elicit sprouting of nearby located intact climbing fibres and the new arbour is able to fully restore synaptic connections which appear normal both morphologically and functionally. Multiple climbing fibre innervation of a single Purkinje cell persists in the adult hypogranular cerebellum. The different fibres are distributed to separate dendritic regions, suggesting a local competition between the different arbours for their territory. It is postulated that in the intact rat, an activity dependent mechanism of the parallel fibre favours the predominance of one arbour with the elimination of its competitors. When the Purkinje cell is deleted, the climbing fibre arbour becomes heavily atrophic and reduced in size. The analysis of the pattern of this atrophy indicates that the climbing fibre arbour is made by two compartments: a proximal one, whose survival depends on the integrity of the inferior olive, and a distal one, which represents the true pre-synaptic site, which strictly depends on the target. The climbing fibre terminal arbour is able to extend its territory of innervation not only when adult intact climbing fibres are confronted with nearby denervated Purkinje cells, but also when an embryonic cerebellum is grafted onto the surface of an adult unlesioned cerebellum. In this case, collaterals of intact climbing fibre arbours elongate through the pial surface, enter the graft to innervate the Purkinje cells. This growth is likely under the influence of a tropic signal released by the embryonic Purkinje cells. This suggests that the sprouting observed in the adult rat following a subtotal inferior olive lesion is also triggered by a similar factor. The axonal elongation and the consequent synaptogenesis are likely guided by local cues. In this condition, the distribution of the new collateral reinnervation occurs within its projectional map. In addition, when the inferior cerebellar peduncle is sectioned at birth, the climbing fibres of the non-deafferented hemicerebellum emit collaterals which cross the midline and innervate cerebellar strips which are symmetrically positioned relative to the intact side. In the grafting experiments, both the migrated and non-migrated Purkinje cells show the typical electrophysiological properties of the mature cerebellum. These data show that the disappearance of neuronal elements is not a necessary prerequisite to allow new neurones to become fully morphologically and functionally integrated into an adult brain. The reciprocal trophic influence between the climbing fibres and the Purkinje cells shown in the present series of experiments are likely operative in the adult brain not only in pathological conditions and they could give a basic contribution to the synaptic plasticity underlying learned behaviour.

Intrinsic properties and environmental factors in the regeneration of adult cerebellar axons

The success of axon regeneration in the adult mammalian brain depends on the presence of growth-permissive environmental conditions as well as on specific properties of the affected neurons. To investigate the relative contribution of extrinsic cues and intrinsic determinants to reparative processes we have investigated the regenerative properties of olivocerebellar and Purkinje cell axons. When these axon populations are severed in the cerebellar white matter and confronted with embryonic neural grafts of cerebellar or extracerebellar origin, the former vigorously regenerate into the transplant, whereas the latter invariably fail to do so (Rossi et al., 1995). The same response occurs when dissociated Schwann cells are implanted in the lesion site: Purkinje cell axons fail to regrow, whereas olivocerebellar fibres regenerate for considerable distances. Within the graft, regenerating fibres follow tortuous courses along Schwann cell bundles and sometimes end with poorly developed terminal plexuses. Some of them, however, succeed in crossing the graft and grow further into the host cortex, where they break into fine terminal branches confined to the granular layer. The remarkable regenerative response of olivocerebellar axons revealed by these experiments might be an intrinsic reaction of the affected neurons to axon injury or it might be elicited by growth promoting cues derived from the grafts. To elucidate this point we have undertaken the investigation of cellular changes occurring in adult inferior olivary neurons following the transection of the inferior cerebellar peduncle. Our results show that axotomy induces a series of cellular changes, or reparative and regressive character, which ultimately lead to cell death. Interestingly, however, these modifications are not uniformly distributed throughout the whole inferior olive. (i) Neuronal atrophy and degeneration progress more rapidly in the PO and DAO than in the MAO. (ii) A subpopulation of inferior olivary neurons become reactive for NADPH-diaphorase histochemistry, and their preferential localisation in the MAO suggests that this modification is related to the longer survival of these cells after axotomy. (iii) The developmentally regulated calcitonin gene-related peptide (CGRP) is reexpressed by a subset of neurons in the caudal nuclear compartments. These results further emphasise the conclusion that the dissimilar regenerative response of Purkinje cell and olivocerebellar axons confronted with permissive environmental conditions is due to different intrinsic properties of these neuronal populations. The reexpression of developmentally regulated substances by axotomised inferior olivary neurons suggests that their reparative reaction is triggered by axon injury. However, the pattern of growth of regenerating olivocerebellar axons is strongly conditioned by environmental constraints, which, in the present experimental conditions, do not allow them to reattain denervated Purkinje cells.

Activities of glycolipid glycosyltransferases and sialidases during the early development of Xenopus laevis

The activities of glycosyltransferases and sialidases, together with the ganglioside content and distribution, have been extensively studied in mammals, while the informations on tissues of other animals, including amphibian, are scarce. In this paper we present data on the activities of SAT-1, SAT-2, SAT-4, SAT-5, GlcNAcT-1, GalNAcT-1, GalT-6, and sialidases studied in Xenopus laevis embryos at different stages of development. The highest activity was found at days 4 and 5 of embryogenesis for glycosyltransferases and sialidases respectively; a tentative correlation between the in vitro activity of these enzymes and the content of neutral and acidic glycolipids is discussed.

AT1 receptors mediate pressor responses induced by angiotensin II in the periaqueductal gray area of rats

Microinjection of angiotensin II (ANGII) (0.01 to 1 nmol) into the periaqueductal gray area (PAG) of anaesthetised rats caused dose-dependent increases in blood pressure. Preinjection (10 min before) of losartan (a selective non-peptide AT1 receptor antagonist; 50 nmol) to the PAG reduced the pressor response to ANGII whereas PD123319 (a selective non-peptide AT2 receptor antagonist; 50 nmol) did not affect the ANGII-induced hypertension. Thus, our data suggest that the activation of AT1 but not AT2 receptors mediates ANGII-induced blood pressure changes in the PAG area.

Nitric oxide regulatory role in sensitized guinea pig trachea

Nitric oxide (NO) has been cited to play an important regulatory role in airway function. Moreover, the NO synthase expression in models of inflammation is documented. The aim of this study was to investigate, in vitro, the NO modulation of cholinergic responses in sham-sensitized and ovalbumin-sensitized guinea pig trachea by using L-arginine (L-ARG), a precursor of NO synthesis, and L-Ng-nitro-arginine-methyl-ester (L-NAME), an inhibitor of NO synthase. Our results showed that NO's ability to modulate cholinergic responses in ovalbumin-sensitized guinea pig trachea is lost. Indeed L-ARG and L-NAME modify acetylcholine sensitivity in sham-sensitized guinea pig but not in ovalbumin-sensitized guinea pig.

Pulmonary concentrations of dirithromycin and erythromycin during acute exacerbation of mild chronic obstructive pulmonary disease

We compared the concentrations of dirithromycin and erythromycin at steady state in serum and the intrapulmonary region in patients suffering from acute exacerbation of mild chronic obstructive pulmonary disease. Twenty patients received dirithromycin, 500 mg given orally once daily for five consecutive days. The other 20 patients were treated with erythromycin base, which was administered orally four times daily at a total daily dose of 1000 mg for seven days. All patients were divided into eight groups, with five subjects in each group, according to sampling times (2, 4, 8, and hrs after the last dose) and treatment. After the erythromycin treatment mean serum concentrations were higher than those of dirithromycin treatment mean serum concentrations were higher than those of dirithromycin for upto 4 hours, but they were undetectable 24 hours after the last dose. At all time periods, the concentrations of dirithromycin in bronchial secretion, bronchial mucosa and epithelial lining fluid were greater than the concentration in serum. Concentrations of erythromycin were always lower than those of dirithromycin in the explored pulmonary sites. Our data demonstrated that a five day course of 500 mg of dirithromycin once daily induced higher concentrations and longer persistence in the various potential sites of pulmonary infection than a seven day course of 250 mg of erythromycin every 6 hrs. The shorter duration of therapy and the once daily dosing with good efficacy against common respiratory pathogens would be advantageous for patients and would be likely to promote better patient compliance and acceptability.

Leukocyte integrin very late antigen-4/vascular cell adhesion molecule-1 adhesion pathway in splanchnic artery occlusion shock

We investigated the role played by the very late antigen-4 (VLA-4)/ vascular cell adhesion molecule-1 (VCAM-1) interaction in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, serum tumour necrosis factor (TNF-alpha), monocyte and lymphocyte cell count and the responsiveness to acetylcholine of aortic rings were studied. Furthermore we investigated the VCAM-1 expression on vessel endothelium and the percentage of VLA-4 positive leukocytes. Splanchnic artery occlusion shocked rats had a decreased survival time (76 +/- 10 min, while sham shocked rats survived more than 4 h), increased serum levels of TNF-alpha (328 +/- 11 U/ml), a decreased number of both monocytes and lymphocytes and reduced responsiveness to acetylcholine (10 nM-10 microM) of aortic rings. In addition we found an increased expression of endothelial VCAM-1 on aortic rings and a reduced percentage of VLA-4 positive lymphocytes and monocytes. Passive immunization with specific antibodies raised against either VCAM-1 or VLA-4 (2 mg/kg, i.v., 3 h before splanchnic artery occlusion shock) increased survival, improved monocyte and lymphocyte count and restored the responsiveness of aortic rings to acetylcholine (P < 0.01). Finally, inhibition of TNF-alpha biosynthesis reversed the increased endothelial expression of VCAM-1 and the reduced percentage of integrin VLA-4 positive leukocytes. Our findings suggest that (i) VLA-4/VCAM-1 interaction has a role in the pathogenesis of circulatory shock; (ii) this interaction might be a target for new therapeutic approaches to the therapy of low-flow states.

Evidence that A(2a) and not A(2b) purinoceptors are coupled to production of nitric oxide in the central regulation of blood pressure

In a previous study we reported that nitric oxide (NO) partially mediates centrally the decrease of arterial blood pressure induced by adenosine A(2) subtype receptor stimulation. The present study confirms the earlier suggestion and shows that in adult male normotensive anaesthetized rats 5'-N-ethylcarboxamidoadenosine (NECA), a non-selective adenosine receptor agonist, centrally injected induced a significant decrease of arterial blood pressure. Moreover, the observation that intracerebroventricular (i.c.v.) administration of N(ω)-nitro-l-arginine methyl ester (l-NAME), a NO synthase inhibitor, +8-(3-chlorostyryl)-caffeine (CSC), antagonist of A(2a) receptors, did not reduce furthermore the hypotensive effect induced by NECA injection, demonstrated that NO is involved only via A(2a) and not via A(2b) adenosine subtype receptors in the central regulation of blood pressure.

Cardiovascular responses induced by injection of endothelin-1 into the superior colliculus of rats

Microinjection of endothelin-1 (1-10-100 pmol) into the superficial layer of the superior colliculus of anaesthetised rats caused dose-dependent decreases in blood pressure. This is unlikely to be a non-specific effect, for angiotensin II (1 nmol) caused increases in blood pressure. Injection of endothelin-1 (10 pmol) into the superior colliculus also caused falls in renal blood flow as measured by an ultrasonic flow probe. Decreases in blood pressure and falls in renal blood flow induced by injection of endothelin-1 into the superior colliculus were unaffected by bilateral vagotomy suggesting that attenuations in the activity of the sympathetic nervous system were involved in these events.

Priming of monocyte respiratory burst by beta-amyloid fragment (25-35)

In the present study we have examined the ability of the beta-amyloid peptide (A beta(25-35)) to modulate the respiratory burst activity of human monocytes in vitro. Incubation of the cells for 24 h with A beta(25-35) as well as with A beta(1-42) resulted in an enhanced production of reactive oxygen radicals (ROI) in response to phorbol 12-myristate 13-acetate (PMA). Such effect was additively increased by coincubation with interferon-gamma (IFN gamma), and was paralleled by modulation of gene and protein expression of some components of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system. Since the effects of A beta(25-35) were also reproduced in primary rat microglia, our findings indicate that A beta(25-35) can potentiate the ability of mononuclear phagocytes to produce ROI, and add further insights into its biological effects.

Mechanisms of stimulation of the respiratory burst by TNF in nonadherent neutrophils: its independence of lipidic transmembrane signaling and dependence on protein tyrosine phosphorylation and cytoskeleton

This study concerns the controversial problem of whether the TNF-alpha (TNF) induces a respiratory burst in human neutrophils in suspension. The results have shown that in these cells TNF induces a classical respiratory burst. In fact, the production of oxygen free radicals 1) is linked to the translocation of NADPH oxidase components from cytosol to the plasma membrane, 2) does not take place in neutrophils from a patient lacking the cytochrome b558, and 3) does not involve other sources such as mitochondrial respiratory chain or xanthine oxidase. Signal transduction studies have demonstrated that this respiratory burst 1) is not accompanied by calcium transients, stimulation of phosphoinositide turnover, and phospholipase D activity (moreover, this burst is associated with the stimulation of the activity of phospholipase A2, but not of sphingomyelinase); 2) is strictly dependent on activation of tyrosine kinases, which is functional to the translocation to the plasma membrane of the cytosolic NADPH oxidase component rac; and 3) is dependent on the integrity of the cytoskeleton because it is completely suppressed by cytochalasin B. The integrity of the cytoskeleton is required for a full translocation of all the NADPH oxidase components and for an optimal activation of tyrosine kinases, but not for phospholipase A2 activation. Taken together, these findings demonstrate that TNF activates the NADPH oxidase through stimulation of tyrosine kinases, whose function is cytoskeleton-dependent, and raise the problem of whether the activation of this respiratory burst involves signals arising from TNF-activated beta2 integrins.

Mechanisms of stimulation of the respiratory burst by TNF in nonadherent neutrophils: its independence of lipidic transmembrane signaling and dependence on protein tyrosine phosphorylation and cytoskeleton

This study concerns the controversial problem of whether the TNF-alpha (TNF) induces a respiratory burst in human neutrophils in suspension. The results have shown that in these cells TNF induces a classical respiratory burst. In fact, the production of oxygen free radicals 1) is linked to the translocation of NADPH oxidase components from cytosol to the plasma membrane, 2) does not take place in neutrophils from a patient lacking the cytochrome b558, and 3) does not involve other sources such as mitochondrial respiratory chain or xanthine oxidase. Signal transduction studies have demonstrated that this respiratory burst 1) is not accompanied by calcium transients, stimulation of phosphoinositide turnover, and phospholipase D activity (moreover, this burst is associated with the stimulation of the activity of phospholipase A2, but not of sphingomyelinase); 2) is strictly dependent on activation of tyrosine kinases, which is functional to the translocation to the plasma membrane of the cytosolic NADPH oxidase component rac; and 3) is dependent on the integrity of the cytoskeleton because it is completely suppressed by cytochalasin B. The integrity of the cytoskeleton is required for a full translocation of all the NADPH oxidase components and for an optimal activation of tyrosine kinases, but not for phospholipase A2 activation. Taken together, these findings demonstrate that TNF activates the NADPH oxidase through stimulation of tyrosine kinases, whose function is cytoskeleton-dependent, and raise the problem of whether the activation of this respiratory burst involves signals arising from TNF-activated beta2 integrins.

Neuronal precursors in the postnatal mouse cerebellum are fully committed cells: evidence from heterochronic transplantations

Neural progenitors are thought to be multipotent cells whose adult phenotype is determined by extrinsic influences acting during and immediately after their last mitosis. To test this hypothesis, postnatal cerebellar precursor cells were placed in the heterochronic cellular environment of the embryonic mouse cerebellar anlage and the resulting phenotypes were determined. To identify the cells arising from postnatal precursors, tissue fragments taken from 3- to 8-day-old cerebellum of several transgenic mouse lines (each expressing the lacZ reporter gene in different sets of neuronal populations) were mixed with fragments taken from the wild-type cerebellar primordium of 12- or 13-day-old embryos. The fragments were dissociated and grafted into the cerebellum of adult mice. The phenotype acquired by postnatal precursors in the mixed grafts was determined by their morphology and ultrastructural features and by the expression of specific markers. Only two adult phenotypes were generated by these precursors: granule cells and molecular layer interneurons. Most granule cells were well integrated in the trilaminated cortex of the graft, being positioned in their proper layer both during development and after complete maturation. By contrast, basket and stellate cells were always ectopic, remaining outside the molecular layer. These results indicate that at least two distinct progenitor cells are present in the postnatal cerebellar cortex under the experimental conditions of this study. Both progenitors appear to be strictly specified at the time of grafting, and neither their identify nor the expression of their major distinctive features are significantly influenced by local signals emerging from the cellular environment of the embryonic cerebellar anlage.

Lisuride and bromocryptine in L-Dopa stable-responder parkinsonian patients: a comparative, double-blind evaluation of cardiopressor and neurochemical effects

In this study, we compared the haemodynamic and biochemical effects of bromocryptine to those of lisuride, in L-Dopa stable responder parkinsonian (PD) patients. Nineteen PD patients were admitted to the study. A double-blind, parallel group, randomized study was performed. Patients were randomly chosen to receive lisuride or bromoryptine. Both drugs were administered in increasing dosages until a maximum of either 0.6 mg lisuride or 7.5 mg bromocryptine was reached. The following tests were carried out: periprandial study, tilt table test and cardiovascular tests (sustained handgrip test, deep-breathing, lying-to-standing and Valsalva manoeuvre). During the tests, systolic and diastolic blood pressure and heart rate were monitored with an automatic sphyngomanometer. Blood samples for catecholamine assay were taken during tilt table test. In basal conditions 70% of the randomly chosen men in the bromocryptine group showed significant orthostatic hypotension (OH), while only one subject in the lisuride group demonstrated comparable OH values. The deepest derangement of orthostatic regulation was observed in the lisuride group but it should not be attributed to the greater hypotensive effects of this drug. Infact, the cardiopressor effects of bromocryptine may well be "masked" by the alteration detected in baseline conditions. Only bromocryptine significantly reduced supine and orthostatic NE plasma levels on the 14th day of therapy. Neither bromocryptine nor lisuride significantly altered periprandial blood pressure values. In conclusion, this study demonstrates that lisuride and bromocryptine are well tolerated as far as the analysis of the development of hypotensive effects is concerned. Further, more sophisticated study, with other agents that block the peripheral and/or central effects of dopamine-agonists in PD patients should be conducted in order better to define the precise role of these types of agents and the potential cardiopressor risks in these subjects.

Pooled human immunoglobulins contain anti-idiotypes with reactivity against the SLE-associated 4B4 cross-reactive idiotype

OBJECTIVE

To identify anti-idiotype antibody activity against a regulatory anti-Sm idiotype (4B4) in pooled human IgG (IVIG).

METHODS

ELISA were used to determine anti-idiotype antibody activity in IVIG.

RESULTS

Anti-idiotype antibody activity to 4B4 was detected in IVIG. The anti-idiotypic activity in IVIG could be inhibited by antigen, Sm, and rabbit anti-idiotypic antiserum. The idiotypic binding activity was predominately directed against the 4B4 VH region.

CONCLUSION

IVIG contains antibodies against a lupus-associated crossreactive idiotype. These antibodies represent Ab2 beta type antibodies. The anti-idiotypic activity in IVIG may be relevant to the efficacious use of IVIG in treating rheumatic diseases.

Different thermostabilities of FLP and Cre recombinases: implications for applied site-specific recombination

Genomic manipulations using site-specific recombinases rely on their applied characteristics in living systems. To understand their applied properties so that they can be optimally deployed, we compared the recombinases FLP and Cre in two assays. In both Escherichia coli and in vitro, FLP shows a different temperature optimum than Cre. FLP is more thermolabile, having an optimum near 30 degrees C and little detectable activity above 39 degrees C. Cre is optimally efficient at 37 degrees C and above. Consistent with FLP thermolability, recombination in a mammalian cell line mediated by a ligand- regulated FLP-androgen receptor fusion protein is more efficient at 35 degrees C than at higher temperatures. We also document a mutation in a commercially available FLP plasmid (FLP-F70L) which renders this recombinase even more thermolabile. The different temperature optima of FLP, FLP-F70L and Cre influence their strategies of usage. Our results recommend the use of Cre for applications in mice that require efficient recombination. The thermolabilities of FLP and FLP-F70L can be usefully exploited for gain of function and cell culture applications.

Angiotensin II, via an action at AT1 receptors, may modulate the behavioural effects of ET-1 in conscious rats

The injection of endothelin-1 (ET-1) (1 pmol/rat) into the dorsolateral periaqueductal gray (PAG) area of freely moving rats induced rotation along the long axis of the body (barrel-rolling). Preinjection (10 min before) of losartan (a selective AT1 receptor antagonist; 50 nmol) to the PAG area reduced the behavioural response to ET-1. In contrast, pretreatment with PD123319 (a selective AT2 receptor antagonist; 50 nmol) did not affect the ET-1-induced barrel-rolling. These results indicate that endogenous angiotensin II, via an action on AT1 receptors, contributes to the barrel-rolling of ET-1 within the brain.

[The therapy of arterial hypertension: a comparison between ACE inhibitors and angiotensin-II-receptor antagonists]

The efficaciousness of ACE inhibitors in arterial blood hypertension is well known. These drugs decreased the incidence of hypertension and myocardial infarction in population. However, they increase tissue levels of some kinines, that may be responsible of some adverse reactions (cough, etc.). Angiotensin-receptor antagonists can minimize the adverse reactions due to kinine accumulation and may increase the safety of the antihypertensive drug-treatment. Pharmacological and clinical aspects of angiotensin-receptor antagonists are discussed.

Tissue and developmental specificity of a polysialo-ganglioside species in the amphibian Xenopus

Xenopus embryos contain a considerable amount of a polysialo-ganglioside not yet fully characterized; in this paper, we will refer to it as ganglioside XI. Preliminary experiments indicate asialo-GMI as the core structure of the ganglioside XI and palmitic and oleic acid as the fatty acids of the ceramide moiety. Further analyses by comparative 2D-TLC with adult fish and chick embryo brains indicate the pentasialilated ganglioside GP1c as the possible structure of XI. In the adult Xenopus, XI characterizes the ganglioside pattern of the central nervous system while is absent in all the other tested tissues. At least two other more polar (presumably richer in sialic acid) bands are often visible under XI, both in embryos and in brain and spinal cord tissues of adult Xenopus. The persistence of polysialo-gangliosides in the brain and spinal cord of adult amphibians could serve to guarantee a proper functioning of the central nervous system at low body temperature.