Identification of harmful drinking in subjects who have had their driving license suspended due to alcohol use: a retrospective Italian study.

OBJECTIVE: Early identification of Harmful Drinking (HD) is difficult, and underestimated. The aim of our retrospective study was to investigate the presence of HD in a population of subjects who had their driving license suspended due to driving under the influence of alcohol. MATERIALS AND METHODS: We retrospectively recruited 979 subjects. During the first appointment (T0), clinical and laboratory characteristics of patients were evaluated, and the AUDIT questionnaire was administered. Two groups were then defined: Harmful Drinking (HD) and non-HD, and all subjects underwent a brief interview for 5-10 minutes before being assigned to a group. RESULTS: 95.9% of our sample were identified as non-HD, whereas 4.1% of them were HD; twenty-one (2.1%) of the HD underwent a control appointment (T1), and 17 (1.7%) of them were diagnosed with alcohol use disorder (AUD); there was a statistically significant reduction in mean daily alcohol intake (p<0.009), and in the mean values of the blood markers of HD between T0 and T1 in HD. CONCLUSIONS: The present study shows that 4.1%, and 1.7% of subjects presented a diagnosis of HD and AUD, respectively, and their entry in a protocol of drinking monitoring proved beneficial in reducing alcohol intake. Thus, the implementation of strict surveillance of subjects found driving under the influence of alcohol involving a network of professional figures (from police forces to specialists in alcohol addiction treatment) may help to detect and to treat subjects with HD and AUD, and to monitor their alcohol use over time.

Proliferative and antigenic properties of rectal cells in patients with chronic ulcerative colitis.

Two markers related to preneoplasia were studied simultaneously in ulcerative colitis (UC). The renewal of the rectal epithelial cells together with expression of second-trimester fetal antigen (STFA) were evaluated in nine patients with UC and four healthy subjects. Endoscopic biopsies were incubated with tritiated thymidine. Cell renewal was studied with microautoradiography, and the antigenic properties of the cells were evaluated by indirect immunofluorescence. At the time of the study, all the UC patients were in a mildly active or in a quiescent stage of the disease; their biopsies did not show dysplastic or neoplastic changes in epithelial cells. STFA was expressed in five UC patients. The analysis of cell renewal in this group revealed a shift of the proliferative compartment towards the luminal surface of the colonic crypts. By contrast, the patient group with STFA-negative reactions showed a pattern of cell proliferation similar to that observed in the controls. These results suggest that the expression of STFA in colonic mucosa is associated with an expansion of the epithelial stem cell population or with arrested cell differentiation, and it may represent a phenotypic marker of proneness of the mucosa toward neoplastic development.

Polymethylene tetraamines as muscarinic receptor probes.

The possibility that polymethylene tetraamines act as divalent ligands has been explored. Structure-activity relationship studies among polymethylene tetraamines have shown that four nitrogens are necessary for high affinity binding to M2 receptors while being less important for M3 muscarinic receptors. Replacement of one terminal methoxybenzyl group of the potent and selective muscarinic antagonist methoctramine by different moieties led to weaker antagonists suggesting that the two terminal nitrogens of methoctramine interact with two similar receptor sites. Data are presented which suggest that methoctramine might interact with four acidic residues of the receptor: two residues are buried in the third transmembrane segment whereas the others are located extracellularly on the loop 4-5 which may represent the allosteric site where several antagonists such as gallamine bind. An hypothetical model describing the interaction of methoctramine with the M2 receptor is proposed. It may provide a useful working hypothesis for the design of new selective muscarinic ligands.

LC determination of leuprolide component amino acids in injectable solution by phanquinone pre-column derivatization labelling procedure.

A sensitive LC method for the determination of leuprolide acetate component amino acids in injectable solution with fluorogenic pre-column derivatization has been developed. The derivatization reaction with phanquinone was optimised by a series of experiments. Histidine, arginine, serine, tryptophan, glutamic acid, tyrosine, methionine, isoleucine, leucine and phenylalanine were separated on a reversed-phase ODS column using as eluent a binary mixture of triethylammonium phosphate buffer-methanol, under gradient elution conditions. The derivatives were eluted in 30 min with good reproducibility. The hydrolysis reaction of the peptide was carried out at reflux with 12 N hydrochloric acid for 2 h 30 min. The intra-day accuracy of the entire procedure (hydrolysis, derivatization, LC separation) ranged from 80.5 to 109.5% of the nominal concentration of leuprolide acetate and the precision (%R.S.D.) was less than 5.8%; the inter-day accuracy was in the range 81.5-107.2% and corresponding R.S.D. values were less than 4.6%. The detection limits (signal-to-noise ratio=3) for the adducts are 30-800 fmol.

Design, synthesis, and biological activity of methoctramine-related tetraamines bearing an 11-acetyl-5,11-dihydro-6H-pyrido[2,3-b][1,4] benzodiazepin-6-one moiety: structural requirements for optimum occupancy of muscarinic receptor subtypes as revealed by symmetrical and unsymmetrical polyamines.

Tetraamines 5-13 and diamines 14-17 as well as monoamine 18 were synthesized, and their biological profiles at muscarinic receptor subtypes were assessed by functional experiments in isolated guinea pig left atrium (M2) and ileum (M3) and by binding assays in rat cortex (M1), heart (M2), and submaxillary gland (M3) homogenates and NG 108-15 cells (M4). An appropriate number and type of substituents on the terminal nitrogens of a tetraamine backbone afforded compounds, such as tripitramine (8) and dipitramine (6), which are endowed with different affinity and selectivity profiles. Tripitramine, a nonsymmetrical tetraamine, resulted in the most potent and the most selective M2 muscarinic receptor antagonist so far available (pA2 = 9.75 +/- 0.02; pKi = 9.54 +/- 0.08). However, it failed to discriminate between M1 and M4 muscarinic receptor subtypes (selectivity ratio: M2/M3, 1600-2200; M2/M1, 81; M2/M4, 41; M1/M3, 28; M4/M3, 55; M4/M1, 2). Dipitramine, another nonsymmetrical tetraamine bearing two substituents on the same terminal nitrogen, displayed the highest affinity for M1 muscarinic receptors (pKi = 8.60 +/- 0.15) and was able to differentiate, unlike 8, all four muscarinic receptor subtypes investigated (selectivity ratio: M1/M2, 5; M1/M3, 2700; M1/M4, 76; M2/M3, 260-520; M2/M4, 15; M4/M3, 35). The results are discussed in terms of a possible mode of interaction of tetraamines with muscarinic receptor subtypes.

Hexahydrochromeno[4,3-b]pyrrole derivatives as acetylcholinesterase inhibitors.

In a search for less flexible analogues of caproctamine (1), a diamine diamide endowed with an interesting AChE affinity profile, we discovered compound 2, in which the terminal 2-methoxybenzyl groups of 1 have been incorporated into a tricyclic system. Since this compound retains good AChE inhibitory activity and its hexahydrochromeno[4,3-b]pyrrole moiety is reminiscent of the hexahydropyrrolo[2,3-b]indole of physostigmine (3), we have designed and synthesized carbamates 4-6, and their biological evaluation has been assessed in vitro against human AChE and BChE. The 6-carbamate 4 was almost as potent as physostigmine and was 60- and 550-fold more potent than the 7-carbamate 5 and the 8-carbamate 6, respectively. The two enantiomers of 4, (-)-4 and (+)-4, did not show a marked enantioselectivity. Finally, a similar time-dependent pattern of inhibition of AChE was observed for 3 and 4.

WB 4101-related compounds. 2. Role of the ethylene chain separating amine and phenoxy units on the affinity for alpha(1)-adrenoreceptor subtypes and 5-HT(1A) receptors.

WB 4101 (1)-related benzodioxanes were synthesized by replacing the ethylene chain separating the amine and the phenoxy units of 1 with a cyclopentanol moiety, a feature of 6, 7-dihydro-5-[[(cis-2-hydroxy-trans-3-phenoxycyclopentyl)amino]meth yl] -2-methylbenzo[b]thiophen-4(5H)-one that was reported to display an intriguing selectivity profile at alpha(1)-adrenoreceptors. This synthesis strategy led to 4 out of 16 possible stereoisomers, which were isolated in the case of (-)-3, (+)-3, (-)-4, and (+)-4 and whose absolute configuration was assigned using a chiral building block for the synthesis of (-)-3 starting from (+)-(2R)-2, 3-dihydro-1,4-benzodioxine-2-carboxylic acid ((+)-9) and (1S,2S, 5S)-2-amino-5-phenoxycyclopentan-1-ol ((+)-10). The aim of this project was to further investigate whether it is possible to differentiate between these compounds with respect to their affinity for alpha(1)-adrenoreceptor subtypes and the affinity for 5-HT(1A) receptors, as 1 binds with high affinity at both receptor systems. The biological profiles of reported compounds at alpha(1)-adrenoreceptor subtypes were assessed by functional experiments in isolated rat vas deferens (alpha(1A)), spleen (alpha(1B)), and aorta (alpha(1D)) and by binding assays in CHO and HeLa cells membranes expressing the human cloned alpha(1)-adrenoreceptor subtypes and 5-HT(1A) receptors, respectively. Furthermore, the functional activity of (-)-3, (+)-3, (-)-4, and (+)-4 toward 5-HT(1A) receptors was evaluated by determining the induced stimulation of [(35)S]GTPgammaS binding in cell membranes from HeLa cells transfected with human cloned 5-HT(1A) receptors. The configuration of the cyclopentane unit determined the affinity profile: a 1R configuration, as in (+)-3 and (-)-4, conferred higher affinity at alpha(1)-adrenoreceptors, whereas a 1S configuration, as in (-)-3 and (+)-4, produced higher affinity for 5-HT(1A) receptors. For the enantiomers (+)-4 and (-)-4 also a remarkable selectivity was achieved. Functionally, the stereoisomers displayed a similar alpha(1)-selectivity profile, that is alpha(1D) > alpha(1B) > alpha(1A), which is different from that exhibited by the reference compound 1. The epimers (-)-3 and (+)-4 proved to be agonists at the 5-HT(1A) receptors, with a potency comparable to that of 5-hydroxytryptamine.

Universal template approach to drug design: polyamines as selective muscarinic receptor antagonists.

The concept that polyamines may represent a universal template in the receptor recognition process is embodied in the design of new selective muscarinic ligands. Tetraamines 4-7 and 16-20 and diamine diamides 8-15 were synthesized, and their pharmacological profiles at muscarinic receptor subtypes were assessed by functional experiments in isolated guinea pig left atrium (M2) and ileum (M3) and by binding assays in rat cortex (M1), heart (M2), submaxillary gland (M3), and NG 108-15 cells (M4). It has been confirmed that appropriate substituents on the terminal nitrogens of a tetraamine template can tune both affinity and selectivity for muscarinic receptors. The novel tetraamine C-tripitramine (17) was able to discriminate significantly M1 and M2 receptors versus the other subtypes, and in addition it was 100-fold more lipophilic than the lead compound tripitramine. Compound 14 (tripinamide), in which the tetraamine backbone was transformed into a diamine diamide one, retained high affinity for muscarinic subtypes, displaying a binding affinity profile (M2 > M1 > M4 > M3) qualitatively similar to that of tripitramine. Both these ligands, owing to their improved lipophilicity relative to tripitramine and methoctramine, could serve as tools in investigating cholinergic functions in the central nervous system. Furthermore, notwithstanding the fact that the highest affinity was always associated with muscarinic M2 receptors, for the first time polyamines were shown to display high pA2 values also toward muscarinic M3 receptors.

Design, synthesis, and biological activity of methoctramine-related polyamines as putative G(i) protein activators.

The universal template approach provided a prospect of modifying methoctramine (2) structure. Thus, polyamines 3-7 were designed in which the flexibility of the diaminohexane spacer of 2 was replaced by a bipiperidinyl moiety. In electrically stimulated guinea pig left atria, these novel polyamines, unlike prototype 2, displayed a potent intrinsic activity, which was in contrast with the muscarinic antagonism shown in binding studies by some of them (3 and 4) and was inhibited by benzalkonium chloride, an inhibitor of G(i) proteins.

Analogues of prazosin that bear a benextramine-related polyamine backbone exhibit different antagonism toward alpha1-adrenoreceptor subtypes.

Hybrid tetraaamine disulfides 4-9 were synthesized by combining the structural features of prazosin (1), a competitive alpha1-adrenoreceptor antagonist, and benextramine (2), an irreversible alpha1/alpha2-adrenoreceptor antagonist, and their biological profiles at alpha1-adrenoreceptor subtypes were assessed by functional experiments in isolated rat vas deferens (alpha1A), spleen (alpha1B), and aorta (alpha1D). To verify the role of the disulfide moiety on the interaction with alpha1-adrenoreceptor subtypes, carbon analogues 10-15 were included in this study. All quinazolines lacking the disulfide bridge behaved, like 1, as competitive antagonists, whereas all polyamine disulfides displayed a nonhomogeneous mechanism of inhibition at the three subtypes since they were, like 2, noncompetitive antagonists at the alpha1A and alpha1B subtypes while being, unlike 2, competitive antagonists at the alpha1D. In particular, the blocking effects were characterized by a decrease of the maximal response to noradrenaline that was affected only slightly by washings. Probably the alpha1A and alpha1B subtypes bear in the binding pocket a suitable thiol function that would suffer an interchange reaction with the disulfide moiety of the antagonist and which is missing, or not accessible, in the alpha1D subtype. Polyamines 8, 9, and 14, among others, emerged as promising tools for the characterization of alpha1-adrenoreceptors, owing to their receptor subtype selectivity. Finally, the effect of nonbasic substituents on the phenyl ring of prazosin analogues 16-28 on potency and selectivity for the different subtypes can hardly be rationalized.

Design, synthesis, and biological evaluation of symmetrically and unsymmetrically substituted methoctramine-related polyamines as muscular nicotinic receptor noncompetitive antagonists.

The universal template approach to drug design foresees that a polyamine can be modified in such a way to recognize any neurotransmitter receptor. Thus, hybrids of polymethylene tetraamines and philanthotoxins, exemplified by methoctramine (1) and PhTX-343 (2), respectively, were synthesized to produce novel inhibitors of muscular nicotinic acetylcholine receptors. Polyamines 3-25 were synthesized and their biological profiles were evaluated at frog rectus abdominis muscle nicotinic receptors and guinea pig left atria (M(2)) and ileum longitudinal muscle (M(3)) muscarinic acetylcholine receptors. All of the compounds, like prototypes 1 and 2, were noncompetitive antagonists of nicotinic receptors while being, like 1, competitive antagonists at muscarinic M(2) and M(3) receptor subtypes. Interestingly, polyamines bearing a low number of methylenes between the nitrogen atoms, as in 3, 6, and 7, displayed a biological profile similar to that of 2: a noncompetitive antagonism at nicotinic receptors in the 7-25 microM range while not showing any antagonism for muscarinic receptors up to 10 microM. Increasing the number of methylenes separating these nitrogen atoms in methoctramine-related tetraamines resulted in a significant improvement in potency at nicotinic receptors. The most potent tetraamine was 19, bearing a 12 methylene spacer between the nitrogen atoms, which was 12-fold and 250-fold more potent than prototypes 1 and 2, respectively. Tetraamines 9-11, bearing a rather rigid spacer between the nitrogen atoms instead of the very flexible polymethylene chain, displayed a profile similar to that of 1 at nicotinic receptors, whereas a significant decrease in potency was observed at muscarinic M(2) receptors. This finding may have relevance in understanding the mode of interaction with these receptors. Similarly, the constrained analogue 12 of methoctramine showed a decrease in potency at nicotinic and muscarinic M(2) receptors, revealing that the tricyclic system, which incorporates the 2-methoxybenzylamine moiety of 1, does not represent a good pharmacophore for activity at these sites. A most intriguing finding was the observation that the photolabile tetraamine 22 was more potent than methoctramine at nicotinic receptors and, what is more important, it inhibited a closed state of the receptor.

In vitro characterization of tripitramine, a polymethylene tetraamine displaying high selectivity and affinity for muscarinic M2 receptors.

1. The antimuscarinic effects of tripitramine were investigated in vitro in isolated driven left (force) and spontaneously beating right (force and rate) atria as well as in the ileum of guinea-pig and rat and in the trachea and lung strip of guinea-pig and compared with the effects of methoctramine. 2. Tripitramine was a potent competitive antagonist of muscarinic M2 receptors in right and left atria. The pA2 values ranged from 9.14 to 9.85. However, in the guinea-pig and rat left atria but not in guinea-pig right atria, tripitramine at lower concentrations (3-10 nM) produced a less than proportional displacement to the right of agonist-induced responses owing to the presence of a possible saturable removal process. 3. Tripitramine was about three orders of magnitude less potent in ileal and tracheal than in atrial preparations (pA2 values ranging from 6.34 to 6.81) which makes it more potent and more selective than methoctramine. 4. Another intriguing finding was the observation that the pA2 value of 7.91 observed for tripitramine in guinea-pig lung does not correlate with that found at both muscarinic M2 and M3 receptor subtypes, which clearly indicates that the contraction of guinea-pig lung strip is not mediated by these muscarinic receptor subtypes. 5. A combination of tripitramine with atropine resulted in addition of the dose-ratios for left atria as required for two antagonists interacting competitively with the same receptor site, whereas the same combination gave a supra-additive antagonism on guinea-pig ileum which suggests that tripitramine interacts with a second interdependent site. 6. Tripitramine was more specific than methoctramine since, in addition to muscarinic receptors, it inhibited only frog rectus abdominis muscular (pIC50 value of 6.14) and rat duodenum neuronal (pIC50 value of 4.87) nicotinic receptors among receptor systems investigated, namely alpha 1-, alpha 2-, and beta 1-adrenoceptors, H1- and H2-histamine receptors, and muscular and neuronal nicotinic receptors.

Analysis of the muscarinic receptor subtype mediating inhibition of the neurogenic contractions in rabbit isolated vas deferens by a series of polymethylene tetra-amines.

The pharmacological characteristics of the presynaptic muscarinic receptor subtype, which mediates inhibition of the neurogenic contractions in the prostatic portion of rabbit vas deferens, have been investigated by using a series of polymethylene tetra-amines, which were selected for their ability to differentiate among muscarinic receptor subtypes. It was found that all tetra-amines antagonized McN-A-343-induced inhibition in electrically stimulated rabbit vas deferens in a competitive manner and with affinity values (pA:(2)) ranging between 6.27+/-0.09 (spirotramine) and 8.51+/-0.02 (AM170). Competition radioligand binding studies, using native muscarinic receptors from rat tissues (M(1), cortex; M(2), heart; M(3), submaxillary gland) or from NG 108-15 cells (M(4)) and human cloned muscarinic M(1)-M(4) receptors expressed in CHO-K1 cells, were undertaken with the same tetra-amines employed in functional assays. All antagonists indicated a one-site fit. The affinity estimates (pK:(i)) of tetra-amines calculated in binding assays using native receptors were similar to those obtained using cloned receptors. Among these compounds some displayed selectivity between muscarinic receptor subtypes, indicating that they may be valuable tools in receptor characterization. Spirotramine was selective for M(1) receptors versus all other subtypes (pK:(i) native: M(1), 7.32+/-0.10; M(2), 6.50+/-0.11; M(3), 6.02+/-0.13; M(4), 6.28+/-0.16; pK:(i) cloned: M(1), 7.69+/-0.08; M(2), 6.22+/-0.14; M(3), 6.11+/-0.16; 6.35+/-0.11) whereas CC8 is highly selective for M(2) receptors versus the other subtypes (pK:(i) native: M(1), 7.50+/-0.04; M(2), 9.01+/-0.12; M(3), 6.70+/-0.08; M(4), 7.56+/-0.04; pK:(i) cloned: M(1), 7.90+/-0.20; M(2), 9.04+/-0.08; M(3), 6.40+/-0.07; M(4), 7.40+/-0.04). Furthermore, particularly relevant for this investigation were tetra-amines dipitramine and AM172 for their ability to significantly differentiate M(1) and M(4) receptors. The apparent affinity values (pA:(2)) obtained for tetra-amines in functional studies using the prostatic portion of rabbit vas deferens correlated most closely with the values (pK:(i)) obtained at either native or human recombinant muscarinic M(4) receptors. This supports the view that the muscarinic receptor mediating inhibition of neurogenic contractions of rabbit vas deferens may not belong to the M(1) type but rather appears to be of the M(4) subtype.

Binding profile of the selective muscarinic receptor antagonist tripitramine.

The binding selectivity of the muscarinic antagonist tripitramine has been tested on the five cloned human muscarinic receptor subtypes (Hm1 to Hm5) expressed in chinese hamster ovary (CHO-K1) cells. The results indicate that tripitramine binds to the muscarinic Hm2 receptor with a Ki value of 0.27 +/- 0.02 nM. Tripitramine distinguishes Hm2 vs. Hm4 by a factor of 24 and vs. Hm3 and Hm5 by a factor of 142 and 125, respectively. A lower affinity ratio, about 6-fold, was found between muscarinic Hm2 and Hm1 receptors. A comparative study with the well-known selective muscarinic M2 receptor antagonist methoctramine indicates that tripitramine has gained both potency and selectivity for the muscarinic Hm2 receptor subtype.

Antagonist binding profile of the split chimeric muscarinic m2-trunc/m3-tail receptor.

Recent evidence suggests that G-protein-coupled receptors can behave as multiple subunit receptors, and can be split into parts, maintaining their binding ability. Transfection of a truncated muscarinic m2 receptor (containing transmembrane domains I-V, named m2-trunc) with a gene fragment coding for the carboxyl-terminal receptor portion of the muscarinic m3 receptor (containing transmembrane domains VI and VII, named m3-tail) results in the formation of a binding site with a high affinity for the muscarinic ligand N-[3H]methylscopolamine. In this paper we analyse the antagonist binding profile of this chimeric m2-trunc/m3-tail receptor in comparison with the wild-type muscarinic m2 and m3 receptors. While many of the substances tested had an intermediate affinity for the chimeric m2-trunc/m3-tail receptor compared with m2 and m3, some compounds were able to distinguish between the chimeric m2-trunc/m3-tail receptor on the one hand and the m2 or the m3 receptor on the other. Among them, tripitramine (a high-affinity M2 receptor antagonist) bound to the m2-trunc/m3-tail receptor with the same affinity as m2, but it bound to the m3 receptor with a 103-fold lower affinity; pirenzepine (a selective muscarinic M1 receptor antagonist) bound to the chimeric receptor with an affinity that was 12- and 3-fold higher than that of m2 and m3, respectively. The results of this study demonstrate that the chimeric m2-trunc/m3-tail receptor has a pharmacological profile distinct from that of the originating muscarinic m2 and m3 receptors.

The design of novel methoctramine-related tetraamines as muscarinic receptor subtype selective antagonists.

Several novel methoctramine-related tetraamines were designed, and their biological profiles at muscarinic receptor subtypes were assessed by functional experiments in isolated guinea pig and rat atria (M2) and smooth muscle (ileum and trachea, M3) and by binding assays in rat cortex (M1), heart (M2), and submaxillary gland (M3) homogenates and NG 108-15 cells (M4). Tripitramine, a nonsymmetrical tetraamine, resulted in the most potent and the most selective muscarinic M2 receptor antagonist of the series (pA2 = 9.14-9.85; pKi = 9.54). Spirotramine (FC 15-94), a symmetrical tetraamine, was able to differentiate between muscarinic M1 receptors (pKi = 7.88) and the other subtypes (M2, pKi = 6.20; M3, pKi = 5.81; M4, pKi = 6.27). Thus, tripitramine and spirotramine could be valuable tools for the pharmacological classification and characterization of muscarinic receptor subtypes.

[Determination of carbohydrate trasferrin (CDT) in the legal medical assessment of being fit to drive]. / Il dosaggio della transferrina carboidrato carente (CDT) nella valutazione medico-legale dell'idoneità alla guida.

BACKGROUND: According to the literature carbohydrate-deficient transferrin (CDT) is thought to be the most sensitive and specific marker of alcohol abuse, but must always be combined with other laboratory tests. Until now the amount of CDT that indicates a state of chronic alcoholism has not been established. Therefore, our aim was to quantify the percentage of CDT that discriminates social drinkers from alcoholics. METHODS: A retrospective study was carried out covering a period of four months on patients who came to us after having their driving licenses suspended for drink driving: 100 male and female subjects aged between 21 and 65 years were examined. This population was compared to a control group of 50 subjects matched for age, who consumed a moderate amount of alcohol, and had never had their driving licenses suspended. RESULTS: The percentage of CDT was found by heterogenous enzyme immunoassay that involves column separation and turbidimetry. There was a notable difference in the amount of CDT between the two groups. The ANOVA and Levene tests were used for statistical analysis. CONCLUSIONS: The authors found the percentage amount of CDT that discriminates the two groups, highlighting the important role of this marker of alcohol abuse in a relevant social context.

[2 cases of Apud cell tumors of the rectum and colon]. / Due casi di tumori a cellule Apud del retto-colon.

Two cases of Apud cell tumour of the rectosigmoid are presented. The question of gross diagnosis and the therapeutic efficacy of polypectomy are discussed. Lastly, an account is given of the morphological, functional and embryogenetic features of these tumours.

Molecular properties of the histamine H2-receptor. Covalent inhibition by tetraamine disulfides.

A series of tetraamine disulfides related to benextramine (an alpha-adrenoreceptor and H2-receptor antagonist) in which the distance between the inner and the outer nitrogens were changed from five to nine methylenes has been studied. Both effects of the displacement of the disulfide bridge by two methylenes and those of the progressive removal of two of the four nitrogens on the pharmacological profile have been assessed. Peak potency appeared to be associated with eight methylenes between the inner and the outer nitrogens and to four cationic charges as in the most active analogue 4 which was also investigated to assess its receptor specificity towards histamine H1 and muscarinic M2 and M3 receptors. The finding that the carbon analogue 11 (two methylenes for the disulfide bridge) was devoid of activity is consistent with the hypothesis that histamine H2-receptor inhibition is the result of a covalent bond formation by a way of a disulfide-thiol interchange reaction between the disulfide moiety of tetraamine disulfides and a receptor thiol group. However, the possibility that tetraamine disulfides may not act at the H2-receptor but beyond the receptor cannot be excluded.

Further investigation on methoctramine-related tetraamines: effects of terminal N-substitution and of chain length separating the four nitrogens on M2 muscarinic receptor blocking activity.

A series of tetraamines related to methoctramine (1) was synthesized and evaluated for its blocking activity on M2 and M3 muscarinic receptors of guinea pig left atria and ileum, respectively. Thus, tetraamines 2-7 were synthesized to evaluate the effect on affinity of replacing the 2-methoxybenzyl moiety of methoctramine by a phenethyl-type substituent. Furthermore, tetraamines 8 and 9 were investigated to analyze the effect on affinity of the chain length separating the inner nitrogens and the inner from outer nitrogens while keeping the total distance between the two outer nitrogens equal to that of methoctramine. It turned out that all the tetraamines investigated, although showing a significant affinity, were less active than methoctramine at M2 muscarinic receptors. The underlying drug-receptor interaction mechanisms are discussed.