3-D numerical simulation of Yb:YAG active slabs with longitudinal doping gradient for thermal load effects assessment

We present a study of Yb:YAG active media slabs, based on a ceramic layered structure with different doping levels. We developed a procedure allowing 3D numerical analysis of the slab optical properties as a consequence of the thermal load induced by the pump process. The simulations are compared with a set of experimental results in order to validate the procedure. These structured ceramics appear promising in appropriate geometrical configurations, and thus are intended to be applied in the construction of High Energy Diode Pumped Solid State Laser (DPSSL) systems working in high repetition-rate pulsed regimes.

The mechanisms of apoptosis in biology and medicine: a new focus for ophthalmology

Defects in apoptosis (programmed cell death) have recently emerged as being closely involved in the pathogenesis of most ocular diseases and, therefore, apoptosis is now a topic of exponential interest in ophthalmology. This review summarizes recent works on mechanisms of apoptosis, from its initiation and modulation to the switching-on of its execution machinery. Interactions of cell death with cell division programs to orchestrate ontogenesis, aging, and adult life and their alterations in human diseases are pointed out. Two main apoptotic signaling pathways are identified: a death receptor-dependent (extrinsic) pathway and a mitochondrion-dependent (intrinsic) pathway. Mitochondrion harbors both antiapoptotic (Bcl-2, Bcl-XL) and apoptotic factors (Smac/Diablo, Apaf-1, cytochrome c). Its permeability transition pore (mPTP) is the main trigger of cell suicide. The process of mPTP opening, in association with extrusion to cytoplasm of a variety of apoptotic factors, is shown. Cytochrome c is one of these apoptotic factors. When expelled to cytoplasm, this double-faced respiratory chain component assembles with two other modules, Apaf-1 and procaspase 9, to form a protein complex--the apoptosome--that starts apoptosis execution. Another respiratory chain component, the CoQ10, is believed to counteract mPTP opening. What makes apoptosis particularly exciting for medicine is that its dysfunctions play a central role in the pathogenesis of several human diseases. For instance, excesses of apoptosis lead to cell loss that accompanies neurodegenerative diseases, whereas genetically determined defects of apoptosis lead to the deregulated cell proliferation typical of cancer. A variety of ophthalmologic diseases, such as post-keratectomy haze, corneal lesions, cataract, glaucoma, senile maculopathies, and genetic ocular pathologies, that underlie apoptosis dysfunctions are treated in detail in the other reviews of this issue.

Polarization state modifications in the propagation of high azimuthal order annular beams

Using a vector Fresnel diffraction propagator we investigate the far-field distributions obtained from guided annular modes with different polarization states. Furthermore we demonstrate that a pure azimuthal polarization transforms into a mainly radial one in the propagation of annular beams with azimuthal mode number higher than 0. This property could enhance the performance of a laser metal-cutting system based on these kind of beams.

Apoptosis is associated with modifications of bcl-2 mRNA AU-binding proteins

The expression of genes requiring finely tuned control is regulated by a posttranscriptional mechanism involving mRNA A + U-rich elements (AREs) cooperating with ARE-binding proteins (AUBPs) in modulation of mRNA stability. We reported previously that an ARE in the bcl-2 mRNA 3'-untranslated region (3'-UTR) had destabilizing activity and was involved in bcl-2 downregulation during apoptosis in vitro. Here we demonstrate that the bcl-2 ARE complexes with a number of specific AUBPs, whose pattern undergoes changes following application of apoptotic stimuli. The caspase inhibitor Z-VAD-fmk strongly attenuates both bcl-2 mRNA decay and bcl-2 AUBP pattern changes elicited by apoptotic stimuli, indicating the involvement of bcl-2 AUBPs in bcl-2 mRNA stability control.

Enantiopure 3-(arylmethylidene)aminoxy-2-methylpropionic acids: synthesis and antiinflammatory properties

Some optically active 3-(arylmethylidene)aminoxy- (3a-g, 4a-g) and fluorenylideneaminoxy-2-methylpropionic acids (5, 6), were prepared as analogues of the antiinflammatory arylpropionic acids of type B, in which the aromatic group is substituted by an MAOM moiety. Some of the new compounds, tested in vivo for their antiinflammatory properties by means of the carrageenan-induced paw edema method in rats, exhibited activity indices similar to that shown in the same test by ibuprofen. Compounds 3a,b and 4a,b, for which at least one of the two enantiomers had shown an inhibition value higher than 40% in the in vivo test, were assayed for their in vitro enzymatic inhibitory activity, showing percentage inhibition values between 40 and 50% at a concentration of 10 microM against COX-2; at the same concentration, they appeared to be devoid of any activity towards COX-1. Compounds 3a,b and 4a,b also proved to possess a similar toxicity. The lack of enantioselectivity shown by compounds 3-6 was tentatively explained in terms of a conformational freedom of the enantiomers which allows their quasi-superimposition.

Synthesis and inhibitory activity towards human leukocyte elastase of new 7alpha-methoxy and 7alpha-chloro (2-acyloxymethyl) cephem derivatives

Some new cephem derivatives of types 4 and 5, viewed as analogues of type I esters in which the atomic sequence of the C-2 ester group is formally inverted, were synthesised and tested in vitro for their inhibitory activity towards human leukocyte elastase and porcine pancreatic elastase. An examination of the inhibition data obtained for the new type 4 and 5 derivatives, while exhibiting a considerable reduction in their activity against porcine pancreatic elastase, indicated that these compounds still maintain an appreciable inhibitory activity against human leukocyte elastase. On this basis the new type of C-2 substitution appears to contribute to the research of new, potentially interesting, cephalosporinic human leukocyte elastase inhibitors.

Induction of apoptosis and mitosis inhibition by degraded DNA lipotransfection mimicking genotoxic drug effects

Genotoxic damage induces cell cycle arrest and/or apoptosis by activation of p53 oncosuppressor protein. A number of anticancer drugs are genotoxic and their damaging effect upon cells is mediated by this mechanism. Microinjection of defined DNA species directly into nucleus has been reported previously to activate p53 and inhibit cell cycle. Here, we demonstrate that simple addition of heterogeneous degraded DNA to cultured cells (Rat-1 fibroblasts) in combination with lipotransfecting agent DOTAP leads to apoptosis induction and mitosis inhibition by a molecular mechanism which mimics that of the cellular response to genotoxic anticancer agents. Indeed, both cellular effects induced by lipotransfected degraded DNA (essentially, heterogeneous small DNA fragments) are associated to p53 activation and modulated by two apoptosis-related genes, such as bcl-2 and c-myc, which also modulate the apoptotic threshold to anticancer agents. Here we raise the hypothesis of exogenous DNA segment lipotransfection as possible new tool for anticancer therapy.

Prevention of corneal keratocyte apoptosis after argon fluoride excimer laser irradiation with the free radical scavenger ubiquinone Q10

PURPOSE

To assess in vitro the potential of the free radical scavenger ubiquinone Q10 in preventing keratocyte apoptosis after argon fluoride (ArF) excimer laser irradiation.

METHODS

Cultured rabbit keratocytes were irradiated at very low single-pulse laser fluences. The cumulative effects generated by three total fluence doses between 12 and 45 mJ/cm2, representative of single-pulse subablative doses during photorefractive keratectomy (PRK) in humans, were evaluated. We employed the following parameters to compare pretreated (10 microM ubiquinone Q10) and untreated samples: 1) number and morphology of living cells by Trypan blue test and ultramicroscopy, respectively; 2) level of free-radical formation assessed by malonaldehyde quantitation; 3) cellular energy level evaluated by ATP assay.

RESULTS

Excimer laser irradiation kills cultured keratocytes by inducing apoptosis. The effect increases with the cumulative fluence dose. In the samples pretreated with ubiquinone Q10 there were significantly fewer cumulative apoptotic events than in the untreated ones. Quantitative analysis of malonaldehyde cellular levels suggested this protective action of ubiquinone Q10 was connected with its ability to scavenge laser-generated free radicals. ATP assay also confirmed that it raised cellular energy levels.

CONCLUSIONS

The treatment of corneal keratocytes with relatively low concentrations of ubiquinone Q10 can prevent apoptosis after ArF excimer laser irradiation. If these findings are confirmed on human keratocytes this treatment could be usefully exploited in the PRK surgical procedure. That might lead to a reduction in the occurrence of haze and curvature regression triggered by programmed cell death.

A conserved AU-rich element in the 3' untranslated region of bcl-2 mRNA is endowed with a destabilizing function that is involved in bcl-2 down-regulation during apoptosis

The control of mRNA stability is becoming recognized as a crucial point of gene expression regulation. A common element responsible for mRNA decay modulation is the adenine- and uracil-rich element that is found in the 3' untranslated region of numerous mRNAs subjected to fast expression changes in response to various stimuli. Previously we identified a post-transcriptional regulation level for the antiapoptotic bcl-2 gene, which could be involved in t(14;18) lymphoma-associated bcl-2 overexpression. Here we demonstrate that bcl-2 mRNA is endowed with an adenine- and uracil-rich element (ARE) characterized by high evolutionary conservation not only among all chordates examined, but even between chordates and the nematode Caenorhabditis elegans (ced-9 gene). As for other well-established destabilizing AREs, the insertion of the bcl-2 ARE downstream from stable beta-globin mRNA causes an enhanced decay of the beta-globin transcript, which proves its functional role. This possibility is corroborated by the fact that the pathway leading to the modulating activity of bcl-2 ARE is influenced by PKC, since the addition of DAG and TPA markedly attenuated the bcl-2 ARE destabilizing potential. Conversely, it is noteworthy that when C(2)-ceramide is added to the culture medium as the apoptotic agent, the beta-globin transcript harboring the bcl-2 ARE undergoes a dramatic increase in decay. This observation clearly indicates that the destabilizing function of bcl-2 ARE is enhanced by apoptotic stimuli and suggests that this element could be involved in a post-transcriptional mechanism of bcl-2 down-regulation during apoptosis. The half-life of the mRNA of bcl-2 in Jurkat cells is prolonged by PKC stimulation and shortened by C(2)-ceramide addition, strongly supporting the view that bcl-2 mRNA stability plays a physiological role in modulating bcl-2 expression, particularly in its down-regulation during apoptosis. Thus, this element becomes a new candidate for mediating those bcl-2 gene expression changes-from apoptosis-associated down-regulation to tumor-associated overexpression-observed thus far that profoundly influence single cell fate and tissue homeostasis.

Extraction of high-quality beams from narrow annular laser sources

We have analyzed the propagation properties of the field produced by circular arrays of coherent optical sources, obtaining the conditions for the generation of good-quality global beams. Such conditions can be obtained by the use of resonators based on the Talbot effect. This appears to be a practical method for the construction of simple, low-cost resonators for compact diffusion-cooled high-power lasers with annular format. Low-loss annular Talbot cavity configurations have also been studied.

Synthesis and beta-adrenergic properties of (Z)-N-[3-(alkylamino)-2-hydroxypropylidene](aryl-methyloxy)amines: effects of the configuration around the methyloxyiminomethyl (MOIM) double bond on the biopharmacological properties of MOIM-type beta-blocking agents

The N-isopropyl- (3a-g) and N-tert-butyl-substituted (4a-g) (Z)-N-(3-(amino)-2-hydroxypropylidene)-(arylmethyloxy)amines were synthesized in order to compare their beta 1- and beta 2-adrenergic properties with those of their previously studied corresponding analogues with the E configuration (1a-g and 2a-g). Compounds 3 and 4 were tested for their affinity for beta 1-a and beta 2-adrenoceptors by radioligand binding experiments, and the compounds with the highest affinity were also assayed for their activity towards the same types of beta-adrenoceptors by functional tests on isolated preparations. The Z-methyloxyiminomethyl (Z-MOIM) compounds 3 and 4 proved to possess, on the whole, affinity (Ki) and activity (PIC50) indices similar to those of the E isomers 1 and 2, thus indicating that for the MOIM-type beta-adrenergic antagonists 1-4, the type of configuration around the MOIM double bond does not have any appreciable effect either on the affinity or on the activity towards beta-adrenoceptors. These results are rationalized on the basis of the steric and electronic analogies existing between the MOIM groups of 1-4 in the two types of configurations (E and Z).

Hybrid stable-unstable resonators for diffusion-cooled CO(2) slab lasers

We present the numerical and experimental study that we carried out to compare the performances of two hybrid stable-unstable resonators for diffusion-cooled CO(2) slab lasers. The two resonators are designed to fit a 320 mm × 60 mm ×2 mm rf-discharge channel and are both guided in the narrow transverse direction. They differ in the other transverse direction, consisting of a positive- or a negative-branch unstable resonator scheme. The two solutions have been characterized in terms of modal structure, power extraction, stability, and quality of the extracted beam.

(E)-(methyloxyimino)acetamides as analogues of neuroleptic benzamides: synthesis and D2-dopaminergic binding affinity

Some type C (E)-(methyloxyimino)acetamides were synthesised as analogues of type A neuroleptic and antipsychotic benzamides, in which the aromatic group is substituted by a methyloxyiminomethyl moiety with the E configuration (CH2ON = CH, E-MOIMM). Type C compounds were tested for their D2-dopaminergic binding affinity in order to obtain an indication of their potential neuroleptic and antipsychotic properties. Biological results showed that only a few aryl-substituted E-MOIM derivatives possess a certain affinity for the D2-dopaminergic receptor, at least one order of magnitude lower than that of metoclopramide and sulpiride.

Synthesis and beta-adrenergic activity of a series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives

In an attempt to change the beta-adrenergic properties of completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives, from antagonist to agonist, while still retaining the beta 2-selectivity, we described, in a previous paper, the synthesis of a series of such derivatives possessing a hydroxy or methoxy group linked to the aliphatic substituent present on the oximic carbon. However, pharmacological tests indicated that these compounds maintain the competitive antagonism on beta receptors. In this paper, the synthesis and the results of functional tests on isolated preparations are reported for a new series of 3-(substituted-benzylideneaminoxy)propanolamine derivatives in which either the hydroxy or the methoxy group is linked to a phenyl ring present on the oximic carbon. The results obtained are then discussed, taking into account the conformational and reactivity properties of these compounds, determined by means of theoretical calculations.

Synthesis and adrenergic beta-blocking activity of ortho-, meta- and para-oxypropanolamino-substituted [(benzylideneamino)oxy]propanolamines

The N-isopropyl- and N-t-butyl-substituted 1-[o-(3-amino-2-hydroxypropoxy)benzylideneaminoxy]-3-amino-2-propa nols (7a,b) and their meta (8a,b) and para (9a,b) isomers, in which a single aromatic ring is substituted both by the oxypropanolaminic chain of (aryloxy)propanolaminic beta-adrenergic antagonists (AOPAs) and the [(methyleneamino)oxy]propanolaminic chain of [(methyleneamino)oxy]-propanolaminic beta-blocking drugs (MAOPAs), were synthesized and assayed for their beta-adrenergic activity by functional tests on isolated preparations. Compounds 7-9 represent a new type of molecular duplication of beta-adrenergic drugs, formally deriving from the sharing of the aromatic portions of two different pharmacophoric subunits, namely the (aryloxy)propanolaminic portion of AOPAs and the [(benzylideneamino)oxy]propanolaminic portion of aryl-substituted MAOPAs. The pharmacological results showed that the beta-blocking activity of compounds 7-9 is closely related to the way in which the two subunits are linked by the aromatic nucleus: the activity decreases on passing from the ortho-compounds (7a,b) to the meta (8a,b) and then to the para (9a,b) isomers. A comparison of this activity trend with those found for series of both beta-blocking AOPAs and aryl-substituted MAOPAs seems to indicate that compounds 7-9 can be considered more as AOPAs substituted on the phenyl ring by a [(methyleneamino)oxy]propanolaminic chain rather than as aromatic MAOPAs substituted on the same phenyl moiety by an oxypropanolaminic portion.

Synthesis and beta-adrenergic activity of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives

In a previous paper, it had been found that completely aliphatic 3-(methylene aminoxy)propanolamine derivatives showed a good beta-blocking adrenergic activity directed prevalently towards beta 2-tracheal receptors. In an attempt to change the beta-adrenergic properties of these compounds from antagonist to agonist, while still retaining the beta 2-selectivity, a series of new completely aliphatic 3-(methyleneaminoxy)propanolamine derivatives were designed in which either a hydroxylic or a methoxylic group was present on the aliphatic portion linked to the oximic carbon. The synthesis of the new compounds and their beta-adrenergic activity, evaluated by means of functional tests on isolated preparations, are described and discussed; the results obtained are then rationalised on the basis of their conformational and reactivity characteristics, determined by means of theoretical methods.

2-(Methyleneaminoxy)methylmorpholine derivatives. Synthesis and antidepressant activity

The 3-(methyleneaminoxy)methylmorpholines 2 were synthesized as analogues of viloxazine 1, an antidepressant drug, in which the aryloxymethyl group is substituted by a (methyleneaminoxy)methyl moiety (MAOMM). Compounds 2 were tested as potential antidepressant agents by using the test of antagonism to reserpine-induced hypothermy in mice. In addition, their anticholinergic and antihistaminic activity on isolated preparations and their ability to antagonize the toxicity induced by adrenaline in mice were evaluated. "In vivo" and "in vitro" tests showed that some compounds of type 2 possess a pharmacological profile similar to that of viloxazine 1.

Locking-range analysis for three coupled lasers

We report a numerical analysis performed to determine the range of parameters necessary for observing stable phase-locked solutions in the case of three next-neighbor coupled lasers. The locking band is determined not only by the coupling strength and by the different array elements' field amplitude ratios but also by the field phase retardation in the coupling channels.

Conformationally restrained analogs of sympathomimetic catecholamines. Synthesis, conformational analysis, and adrenergic activity of isochroman derivatives

In previous papers dealing with the study of the conformations and the biopharmacological activity of conformationally restrained analogs of sympathomimetic catecholamines (NE and ISO), proposals were advanced for the three-dimensional molecular models A, B, and C; these models provided information about the steric requirements for the direct activation of alpha 1, alpha 2,beta 1, and beta 2 adrenoceptors, respectively. The 1-(aminomethyl)-6,7-dihydroxyisochromans 11 and 12 and the 1-(aminomethyl)-5,6-dihydroxyisochromans 13 and 14 (1-AMDICs) are two different types of semirigid analogs of NE and ISO. The alpha 1, alpha 2, beta 1, and beta 2 adrenergic properties of the 1-AMDICs 11-14 were evaluated in vitro, both by radioligand binding assays and by functional tests on isolated preparations, and were compared with those of their parent compounds (NE and ISO). The results of a conformational study carried out by means of both 1H NMR spectrometry and theoretical calculations indicated that, in these 1-AMDICs, the presumed active groups (aryl moiety, amine nitrogen and benzylic ethereal oxygen) are in a spatial relationship corresponding to the one found for NE and ISO in their preferred conformations, which also proved to be the pharmacophoric conformation in the models A-C. By means of a comparison of the stereostructures of the 1-AMDICs 11-14 with their biopharmacological properties, it was possible to obtain a further definition of the model B with respect to the activation of the alpha 2 adrenoceptors; the superimposition of the 1-AMDICs 11 and 12 with the molecular model C made it possible to detect an area of the beta-adrenergic receptors which might hinder the fit of adrenergic drugs that are analogs of catecholamines with these receptors.

Optimal phase filtering for high-power laser array far-field distribution

We present numerical simulations of the propagation of the field emitted by laser arrays consisting of a small number of elements. Our computations show how propagation transforms part of an amplitude modulation into a phase modulation. This fact can be used to enhance the central lobe energy in the far field of high-power laser arrays by means of a simple corrective optical element. We discuss optimal filtering conditions and prove that the quarter-Talbot distance generally used in previous studies is not the best choice.

Antiherpes virus agents: a review

In this review, after some considerations about the structure of the virus and the viral replicative cycle, herpes virus diseases in man are described. The most important antiherpes virus drugs until now discovered are then reported analyzing and examining their chemical structure related to their mechanism of action and their pharmacological activity. Finally, defects of antiherpes virus drugs currently in therapy are shown, in order to outline which directions future developments will have to follow.

Conformational effects on the activity of drugs. 13. A revision of previously proposed models for the activation of alpha- and beta-adrenergic receptors

The alpha 1-, alpha 2-, beta 1-, and beta 2-adrenergic properties of the 2-(3,4-dihydroxyphenyl)morpholines 3 and 4 (2-DPMs), of the 3-(3,4-dihydroxyphenyl)-3-piperidinols 5 and 6 (3-DPPs), and of the trans-2-amino-5,6-dihydroxytetrahydronaphthalen-1-ols 7 and 8 and the trans-2-amino-6,7-dihydroxytetrahydronaphthalen-1-ols 9 and 10 (2-ADTNs) were evaluated in vitro both by radioligand binding assays and by functional tests on isolated preparations and compared with those of norepinephrine (NE, 1) and isoprenaline (ISO, 2). Through a comparison of the stereostructures of the compounds examined with their biopharmacological properties, it was possible to revise previously proposed molecular models for the direct activation of alpha- and beta-adrenergic receptors. The revised models (A-C) provided information about the conformational requirements of adrenergic drugs, which substantially fit in with the results of several published studies involving conformationally-restricted adrenoceptor agonists. The different position of the catecholic hydroxyl groups in model B, which refers to the alpha 2 receptors, and in model C, which refers to the beta receptors, confirms the importance of the rotameric position of the aromatic ring of catecholamines in the interaction with the alpha- and beta-adrenergic receptor.

Dynamic behavior of the optogalvanic effect in a CO(2) laser

We observe the dynamic behavior of the optogalvanic effect in a CO(2) laser during the transient process due to the switching of the cavity losses. A three-level model for the laser and a differential relaxation equation based on thermodynamic considerations for the temperature are used to interpret the phenomenon.

Molecular design, synthesis, and antiinflammatory activity of a series of beta-aminoxypropionic acids

Previous experimental and theoretical studies carried out on the mechanism of action of adrenergic drugs have shown that the (methyleneaminoxy)methyl moiety (C = NOCH2, MAOMM) can be considered as a "bioisostere" of an aryl group (Ar). On this basis, a series of substituted beta-aminoxypropionic acids (AOPAs) were synthesized as analogues of antiinflammatory arylacetic acids (ArAAs), in which the Ar portion is substituted by the MAOMM, with the aim of evaluating whether any antiinflammatory activity could be obtained from this class of drugs after the substitution of the Ar with the MAOMM. The antiinflammatory activity of the AOPAs synthesized was determined by carageenan-induced rat paw edema, using diclofenac as the reference drug. The pharmacological data showed that most of the AOPAs examined exhibit a significant antiinflammatory activity, which in the case of the (E)-3-(benzylideneaminoxy)propionic acid (7q) is very close to that of the reference drug. Structural and theoretical studies were carried out in order to compare the conformation and the molecular reactivity of the AOPAs with those of the ArAAs. Pharmacological results showed that the ArAAs also generally exhibit an antiinflammatory activity after the substitution of the Ar with the MAOMM, thus supporting the hypothesis of a bioisosterelike relationship between these two moieties in this class of NSAIDs.

Synthesis and antimicrobial properties of substituted beta-aminoxypropionyl penicillins and cephalosporins

Some beta-aminoxypropionyl penicillins (3) and cephalosporins (4 and 5), planned on the basis of the hypothesis that the (methyleneaminoxy)methyl group (greater than C = NOCH2) could be a "bioisoster" of either aryls or other aromatic groups, were synthesized and assayed for their antimicrobial properties. Compounds 3-5, tested on Gram-positive and Gram-negative bacteria, both sensitive to enzyme inactivation and otherwise, exhibited an activity trend that was not substantially different from that of the corresponding phenylacetamido derivatives taken as terms of comparison.

Synthesis and evaluation of the pharmacological activity of rigid analogues of sympathomimetic catecholamines derived from bicyclo[2.2.1]heptane

endo-3-Amino-exo-2-(3,4-dihydroxyphenyl)-2-hydroxybicyclo[2.2.1]he ptane (4a) and its N-isopropyl derivative (4b) were synthesized and assayed for their adrenergic activity on various isolated preparations. Compounds 4a and 4b, tested up to a dose of 10(-4) M, did not reveal any activity, either stimulant or blocking, on the alpha- and beta-adrenoceptors. Possible rationalizations of the results obtained, however, are suggested.

An anomalous effect of N-isopropyl substitution in determining beta-adrenergic activity

We report unexpected results in an investigation of cyclic analogues of dopamine and norepinephrine possessing the structures 1-(aminomethyl)-5,6-dihydroxy-1,2,3,4-tetrahydronaphthalene (3) and 1-(aminomethyl)-5,6-dihydroxy-1,2,3,4-tetrahydro-1-naphthalenol (7). N-Isopropyl substitution of these compounds, providing 4 and 8, brings about the total disappearance of their stimulant activity on beta-adrenergic receptors. On the basis of current knowledge about the structure-activity relationship of adrenergic drugs, it is difficult to provide an explanation for these results; however a tentative rationalization based on conformational considerations is suggested.

Role of the (acyloxy)methyl moiety in eliciting the adrenergic beta-blocking activity of 3-(acyloxy)propanolamines

Some totally aliphatic 3-(acyloxy)propanolamines were synthesized with the aim of testing whether beta-blocking activity could be obtained from this class of drugs, even in the absence of an aromatic group. The significant and, in most cases, competitive beta-blocking activity shown by the compounds under examination, together with the results of a theoretical study in which their reactivity was compared with that of other adrenergic beta-blocking drugs, seems to confirm a hypothesis previously advanced on the basis of knowledge about the action mechanism of adrenergic beta-blocking drugs and of the results of structural studies. It was also possible to suggest some considerations about the role played by the (acyloxy)methyl portion of 3-(acyloxy)propanolamines in eliciting their adrenergic beta-blocking activity.

3-[(2-ethoxyphenoxy)methyl]piperidine derivatives. Synthesis and antidepressant activity

The 3-[(2-ethoxyphenoxy)methyl]piperidine derivatives 3-5 were synthesized and screened as potential antidepressant agents by the reserpine interaction test in mice and the evaluation of reuptake inhibition of biogenic amines in pig brain synaptosomal fractions. In addition, their anticonvulsant activity, tested by pentyleneetrazole antagonism, and approximate acute toxicity were evaluated. In vivo and in vitro tests showed that compounds 3 and 5 possess a biological activity comparable to that of the antidepressant drug viloxazine.

Conformational effects on the activity of drugs. 11. Stereostructural models for the direct activation of the alpha- and beta-adrenergic receptor

Two kinds of cyclic analogues of norepinephrine (NE, 7) and isoprenaline (ISO, 8), in which the C(1)-C(2) side chain of these amino alcohols is incorporated in its preferred conformation in the ring of the 2-(3,4-dihydroxyphenyl)-morpholines 9 and 10 (2-DPMs) and in the ring of the 3-(3,4-dihydroxyphenyl)-3-piperidinols 11 and 12 (3-DPPs), respectively, were synthesized and assayed for their adrenergic activity on various isolated preparations. The 2-DPMs and the 3-DPPs showed an alpha- and beta-agonist activity comparable to that of NE and ISO and to that of the trans-2-amino-5,6-dihydroxytetrahydronaphthalen-1-ols 13 and 14 (2-ADTNs), which represent another kind of semirigid analogue of NE and ISO. Through a comparison of the stereo structures of the compounds examined and of their pharmacological properties, it was possible to suggest a spatial situation in which the pharmacophoric groups of the adrenergic drugs examined (aryl moiety, amine nitrogen, and alcoholic or ethereal benzylic oxygen) should interact at the receptor site. This spatial situation corresponds to the one found in the preferred conformation of NE and ISO. It was also possible to construct two theoretical three-dimensional molecular models that provide information about steric requirements for the direct activation of alpha- and beta-adrenoceptors, respectively.

An interdisciplinary approach to the design of new structures active at the beta-adrenergic receptor. Aliphatic oxime ether derivatives

On the basis of results previously obtained from structural and theoretical studies on beta-adrenergic drugs, a series of aliphatic oxime ether derivatives (AOEDs) was synthesized. As expected, pharmacological in vitro tests showed that compounds examined exhibit a marked and competitive antagonism at beta-adrenoceptors; the beta 2/beta 1 selectivity ratio indicated that they are more active on the tracheal than on the cardiac beta-receptor. The chemical reactivity of the AOEDs was studied through the calculation of the electrostatic molecular potential (EMP) on a model compound in its preferred conformation. The results showed that the EMP trend agrees with that previously calculated for other beta-blocking drugs.

Conformational effects on the activity of drugs. 10. Synthesis, conformation, and pharmacological properties of 1-(2,5-dimethoxyphenyl)-2-aminoethanols and their morpholine analogues

In order to obtain a better understanding of the effects that structural parameters have on the changes of adrenergic activity when 1-aryl-2-aminoethanol derivatives are converted into their corresponding 2-arylmorpholine cyclic analogues, we synthesized 1-(2,5-dimethoxyphenyl)-2-aminoethanol derivatives 5-7 and their morpholine analogues 8-10. The preferred conformation of amino alcohols and their cyclic analogues have been determined through an H NMR and IR study. Compounds 5 and 6 showed both alpha-stimulating and alpha-blocking activity on rat vas deferens, the effect depending on the concentration employed; on the same isolated tissue, N-isopropyl derivative 7 and the morpholine analogues 8-10 exhibited only alpha-blocking activity. As for the beta-adrenergic activity, only the open-chain compound 7 possessed a moderate blocking effect on isolated guinea pig atria. The results of this work seem to indicate that the changes of pharmacological activity involved in the transformation of the adrenergic drugs into their morpholine analogues are influenced more by characteristic features of the aromatic moiety than by the ethanolamine or propanolamine structure of the drugs.

Structure--activity relationship in cinnamamides. 3. Synthesis and anticonvulsant activity evaluation of some derivatives of (E)- and (Z)-m-(trifluoromethyl)cinnamamide

The (E)- and (Z)-m-(trifluoromethyl)-alpha, beta-dimethylcinnamamides and some of their N-alkyl derivatives were prepared and pharmacologically tested as anticonvulsant agents in order to verify if a ring substituent, like the m-CF3 group, different from a halogen but possessing the same electronic effect could lead to equally active compounds. Some (E)-m-(trifluoromethyl)-alpha-methyl- and -non-methyl-substituted-cinnamamides were also prepared and tested. In the alpha, beta-dimethyl series the results show that the m-CF3 group leads to products more active than the ones unsubstituted on the phenyl ring but still less active than the p-halogen-substituted compounds previously studied. In the alpha-methyl and non-methyl-substituted series, the trend shows the m-CF3 group being able to produce less toxic and, in some cases, more active products than the previously studied amides.

Conformational effects on the activity of drugs. 7. Synthesis and pharmacological properties of 2-(p-nitrophenyl)-substituted morpholines

A series of 1-(p-nitrophenyl)-2-aminoethanol derivatives and their morpholine analogues have been synthesized and pharmacologically investigated in order to confirm some pharmacological observations made with the N-isopropyl-substituted compounds. In agreement with the previously obtained results, the weak alpha-adrenergic-stimulating activity and the potentiating effect on the responses to norepinephrine found in the open-chain compounds persist in their corresponding semirigid cyclic analogues. The results are discussed in the light of common knowledge of the structure-activity relationships of alpha-adrenergic drugs.