Evaluating the effect of COVID-19 incidence on Emergency Departments admissions. Results from a retrospective study in Central Italy during the first year of pandemic

Introduction

The COVID-19 pandemic has had a major impact on the Healthcare System, changing the patterns of Emergency Department access. In fact, accesses for trauma and less severe cases decreased significantly. This decline has generally been attributed to both the effects of the lockdown, imposed by the government, and the fear of being infected by SARS-CoV-2 in the hospital. However, the correlation between these elements is not yet clear, since the accesses to the Emergency Department did not increase either at the end of the lockdown or in the summer when the epidemiological situation was more favorable. Aim: To evaluate the association between trends of Emergency Department accesses and COVID-19 incidence in 2020.

Methods

Data on Emergency Department accesses, by month and severity triage code, from 14 hospitals in southeastern Tuscany (Italy) were obtained from hospitals' data warehouse. Official data on new cases of COVID-19 infection were used to calculate incidence. Hospitals were classified into 4 categories. Differences in Emergency Department access by month, triage code, and hospital type were investigated using Kruskal-Wallis analysis. Association between Emergency Department accesses and COVID-19 incidence was evaluated using a random-effect panel data analysis, adjusting for hospital type and triage code.

Results

The trend of 268,072 Emergency Department accesses decreases substantially at the first pandemic peak; thereafter, it increased and decreased again until the minimum peak in November 2020. COVID-19 incidence appeared to be overlapping with an inverse direction. Monthly differences were significant (p<0.01) except for most severe codes. There was a significant inverse association between Emergency Department accesses and COVID-19 incidence (Coef. =-0.074, p<0.001) except for most severe cases (triage code 1: Coef. =-0.028, p=0.154).

Conclusion

Emergency Department admissions trend followed the COVID-19 incidence, except for the most severe cases. Fear of infection seems to discourage patients from accessing Emergency Department for illnesses perceived as not serious.

COVID-19 incidence on Emergency Departments accesses. Health need and fear of infection, what wins?

Introduction

The COVID-19 pandemic has changed the patterns of access to the Emergency Department (ED), but it is unclear whether this change was due to COVID-19 incidence or the lockdown imposed by law.

Aim

To evaluate the association between trends of ED accesses and COVID-19 incidence in the period 1 January - 31 December 2020.

Material and methods

The data of accesses to the ED per month and severity triage code of 14 hospitals in the Southeast Tuscany (Italy, Provinces of Siena, Arezzo, Grosseto) were obtained from hospitals data warehouses. Data on new cases of COVID-19 infection (obtained by the Ministry of Health) for the 3 provinces were used to calculate the incidence of infection. Hospitals were classified in 4 categories based on beds number, medical specialties offered, services provided. Differences in ED accesses by month, triage code and hospital type were investigated by a Kruskal-Wallis analysis of variance. Association between ED accesses and COVID-19 incidence was evaluated using a random effect panel data analysis adjusting for hospital type and triage code.

Results

A total of 268,072 ED accesses have been studied. Their trends saw a strong decrease in correspondence of the first pandemic peak, subsequently they are increased and then decreased again until the minimum peak in November 2020. COVID-19 incidence appeared to overlap, but in the reverse direction, with ED admissions trends. Monthly differences of the ED accesses were significant (p &lt; 0.01) except for most severity code. There is a statistically significant inverse association between ED accesses and COVID-19 incidence (Coef. = -0.074, p &lt; 0.001) except for most severe cases (triage code 1: Coef. = -0.028, p = 0.154).

Conclusions

ED admissions trends followed the COVID-19 incidence independently from the period of lockdown except for the most severe cases. The fear to contract the infection seemed to discourage patients to access ED for diseases that were perceived as not serious.

Key messages

• The pandemic has changed the lifestyle of people worldwide, modifying even the perception that the patient has of own state of health and their access to Emergency Department.

• The decrease in accesses involved less severe cases. Reflect on both the adequacy of accesses in the pre-pandemic period and on what is the best setting to manage these cases in the pandemic period.

Health promotion through collaborative health: a Tuscan model

Background

chronic diseases affect in Italy about 39.1% of the total population and 85.3% of the over 75 years. A new experimental approach has been studied that, through the communities, activate collaborative processes to improve the health and well-being of population. The ASL Toscana Sudest for the three years 2017-2020 has acquired from the Self-management Resource Center (SMRC, University of Stanford California) licenses for implementing self-management programs for chronically ill people. The training process is subject to quality control by SMRC with annual report.

Objectives

the goal is to train participants in the solution of problems, to make decisions, to set objectives and define priorities, to undertake actions for clinical-emotional management and its social role. The self-management education processes carried out have been addressed primarily to the diabetes program.

Results

57 conductors were trained through the administration of 30 hours of frontal lessons to nurses and lay people. Subsequently, the conductors implemented 77 programs in which a total of 750 people participated. Of these, 90% took part in at least four of the six seminars provided for in the program. In addition, a specific program has been launched for a group of 13 Bengali citizens resident in Italy with particular attention to the risk of development of dysmetabolic diseases and the possible correlation with Ramadan.

Conclusions

the engagement of the citizen in terms of Public Health manifests itself with a cumulative impact of small behavioral changes at the level of individuals, communities, and the population. Main message: the project aims to introduce the concept of ‘Collaborative Health' offering concrete examples of experiences already present in the Tuscan context, formulating possible recommendations for stakeholders for the innovation of the system and stimulating greater sustainability, appropriateness and equity of services and health models in Italy.

Key messages

Collaborative health is a winning strategy for health promotion. Chronic diseases are a main topic for health promotion.

Gender-specific violence and/or abuse: strategy for dealing with a hidden phenomenon

Background

Exposing episodes of violence against women or hate crimes was extremely difficult in the past, due to a lack of awareness in emergency departments, the absence of a social, institutional and health network, and poor communication by Anti-Violence Centers. Until about 10 years ago, professional skills employed to address this kind of episodes were strictly related to the specificity of the trauma reported (gynecological, orthopedic, surgical and psychiatric).

Purpose

introduce a necessary holistic approach, that takes into account all aspects of the issue that normally are completely overlooked.

Methods

The “Codice Rosa” project began in the Grosseto Health Department (Tuscany) on 2009. It ensured reserved access to the emergency room for victims of violence, in particular women, children and discriminated persons. Later, it evolved into a regional network for women who have suffered from gender-based violence and for victims of hate crime violence. The project currently includes all victims, no matter whether they access the sanitary service through the emergency room, ambulatory or ordinary hospitalization. It follows a precise alert procedure triggering subsequent steps over the territory, with the goal to ensure ongoing support and a global care scheme.

Results

from 2010 up to July 2019 in the Grosseto Health Department 3483 “Codice Rosa” (mistreatment, abuse, stalking) have been admitted, 3088 adults and 395 minors respectively. In Tuscany from 2012 up to July 2019, the Codice Rosa patients were 20162, 17305 adults and 2857 minors respectively.

Conclusions

The program operates synergistically with other entities, institutions and overall with the local network of Anti-Violence Centers and Social Services, in line with national and international directives. It has provided a strong contribution to the development of current national guidelines in Italy.

Key messages

Gender specific violence and hate crimes phenomenon have to be specifically addressed. Improving the regional/national networks among the various actors involved in the fight against gender violence and hate crimes.

Effects of anticoagulation therapy with vitamin K antagonists on hospitalizations and emergency room accesses in Grosseto (Italy)

Introduction

A lot of drug groups are associated with preventable drug-related admissions. Coumarin derivatives, prescribed for the treatment and prevention of deep vein thrombosis or pulmonary embolism or prevention of systemic embolism or stroke in patients with prosthetic heart valves or atrial fibrillation, are often associated with bleeding. The aim of our study was to analyze how the anticoagulant therapy with VKAs could affects the hospitalizations and the visits to emergency room in the elderly population (> 65 years old).

Methods

In 2013 we conducted a cross sectional study analyzing the database of all pharmaceutical prescriptions, selecting patients living in Grosseto (Italy), which received at least two prescriptions of coumarin derivatives in 2012. We analyzed the admissions to hospital and the accesses to the emergency rooms (ERs) made by each patient, focusing especially on those related to bleeding. For each access to ER we recorded the date, time of stay, diagnosis and outcome. For each hospitalization the information we recorded were the date of admission and discharge diagnosis.

Results

3684 patients were included in our study. 261 (7.1%) patients visited the emergency room for bleeding; 37 (1%) for intracranial bleeding. The accesses made by men were higher than those made by women. The average time of stay in ER was 349 minutes. The admissions to hospital were 96 (2.6%); 42 (1.1%) were admitted to hospital with a diagnosis of major vascular event. 53 patients (20.3%), accessed to the ER more than one time. The 11.5% was admitted to the hospital more than one time.

Conclusions

Our study showed that VKAs are responsible of an increase of the accesses to ER and of the admissions to hospital. However, it would be interesting to enlarge the sample size including patients living in other provinces or in other regions, with a lower age and treated also with TSOACs, in order to evaluate the real cost-effectiveness of anticoagulant therapy.

In vitro and in silico analysis of the vascular effects of asymmetrical N,N-bis(alkanol)amine aryl esters, novel multidrug resistance-reverting agents

Asymmetrical N,N-bis(alkanol)amine aryl esters (FRA77, GDE6, and GDE19) are potent multidrug resistance (MDR) reversers. Their structures loosely remind that of the Ca(2+) antagonist verapamil. Therefore, the aim of this study was to investigate their vascular activity in vitro. Their effects on the mechanical activity of fresh and cultured rat aorta rings on Cav1.2 channel current (I Ca1.2) of A7r5 cells and their cytotoxicity on A7r5 and EA.hy926 cells were analyzed. Docking at the rat α1C subunit of the Cav1.2 channel was simulated in silico. Compounds tested were cytotoxic at concentrations >1 μM (FRA77, GDE6, GDE19) and >10 μM (verapamil) in EA.hy926 cells, or >10 μM (FRA77, GDE6, GDE19) and at 100 μM (verapamil) in A7r5 cells. In fresh rings, the three compounds partly antagonized phenylephrine and 60 mM K(+) (K60)-induced contraction at concentrations ≥1 and ≥3 μM, respectively. On the contrary, verapamil fully relaxed rings pre-contracted with both agents. In cultured rings, 10 μM GDE6, GDE19, FRA77, and verapamil significantly reduced the contractile response to both phenylephrine and K60. Similarly to verapamil, the three compounds docked at the α1C subunit, interacting with the same amino acids residues. FRA77, GDE6, and GDE19 inhibited I Ca1.2 with IC50 values 1 order of magnitude higher than that of verapamil. FRA77-, GDE6-, and GDE19-induced vascular effects occurred at concentrations that are at least 1 order of magnitude higher than those effectively reverting MDR. Though an unambiguous divergence between MDR reverting and vascular activity is of overwhelming importance, these findings consistently contribute to the design and synthesis of novel and potent chemosensitizers.

The functions and structure of ABC transporters: implications for the design of new inhibitors of Pgp and MRP1 to control multidrug resistance (MDR)

Multidrug resistance (MDR) is a kind of acquired resistance of microorganisms and cancer cells to chemotherapic drugs that are characterized by different chemical structure and different mechanism of action. Classic MDR is the consequence of the over-expression of a variety of proteins that extrude the chemotherapic from the cell, lowering its concentration below the effective one. The ABC (ATP Binding Cassette) is a ubiquitous and important family of such transporter proteins. Members of this super family are present in mammals as well as in prokaryotic organisms and use ATP as the energy source to activate the extrusion process. P-glycoprotein (Pgp) and Multidrug Resistance Proteins (MRP1 and sister proteins) are the most important and widely studied members of ABC super family. Our knowledge about the structures and functions of transporter proteins has definitely improved in recent years, following the resolution of the structure of bacterial pumps which opened the way to the building of homology models for the more complex Pgp and MRP. It can be anticipated that these results will have a strong impact on the design of more potent and safer MDR reverters. A huge number of small molecules, many of natural origin, are able to reverse multidrug resistance by inhibiting the functions of Pgp, MRP1 and sister proteins and their action has been considered a possible way to reverse MDR. However, while a few compounds have reached clinical trials, none of them has, so far, been cleared for therapeutic use. Two main reasons are at the base of this difficulty: i) MDR is a complex phenomenon that may arise from several different biochemical mechanisms, with the consequence that inhibition of transporter proteins may be insufficient to reverse it; ii) the physiological role of Pgp and sister proteins requires more potent modulators with proper selectivity and pharmacokinetic in order to avoid unwanted side effects. This paper first reviews the most recent discoveries on the structures and functions of the ABC super family, in particular Pgp and MRP. Then, the medicinal chemistry of MDR reverters, in light of these findings, is discussed and the molecules that are presently in development are reviewed.

The medicinal chemistry of multidrug resistance (MDR) reversing drugs

Multidrug resistance (MDR) is a kind of resistance of cancer cells to multiple classes of chemotherapic drugs that can be structurally and mechanistically unrelated. Classical MDR regards altered membrane transport that results in lower cell concentrations of cytotoxic drug and is related to the over expression of a variety of proteins that act as ATP-dependent extrusion pumps. P-glycoprotein (Pgp) and multidrug resistance protein (MRP1) are the most important and widely studied members of the family that belongs to the ABC superfamily of transporters. It is apparent that, besides their role in cancer cell resistance, these proteins have multiple physiological functions as well, since they are expressed also in many important non-tumoural tissues and are largely present in prokaryotic organisms. A number of drugs have been identified which are able to reverse the effects of Pgp, MRPI and sister proteins, on multidrug resistance. The first MDR modulators discovered and studied in clinical trials were endowed with definite pharmacological actions so that the doses required to overcome MDR were associated with unacceptably high side effects. As a consequence, much attention has been focused on developing more potent and selective modulators with proper potency, selectivity and pharmacokinetics that can be used at lower doses. Several novel MDR reversing agents (also known as chemosensitisers) are currently undergoing clinical evaluation for the treatment of resistant tumours. This review is concerned with the medicinal chemistry of MDR reversers, with particular attention to the drugs that are presently in development.

Non-invasive quantitative monitoring of cerebral blood flow in aneurysmal subarachnoid haemorrhage with 99mTc-ECD

The purpose of this prospective study was to detect symptomatic cerebral vasospasm in aneurysmal subarachnoid haemorrhage (SAH) by a non-invasive mean cerebral blood flow (mCBF) quantification using 99mTc-ethyl cysteinate dimer. Measurement of mCBF without blood sampling and single photon emission tomography (SPECT) were performed at 1 and 7 days after surgery in 35 consecutive SAH patients, of whom 16 were examined at day 30 as well. A decrease in mCBF of more than 10% on day 7 versus day 1 was considered to indicate vasospasm. On visual interpretation of SPECT, a perfusion decrease which appeared newly on day 7 was considered to indicate vasospasm. In total, nine of 35 patients had cerebral vasospasm confirmed by computed tomography (CT) and/or angiography. The mCBF measurement showed a 77.8% (7/9) sensitivity, a 88.5% (23/26) specificity, a 70.0% (7/10) positive predictive value, and a 92.0% (23/25) negative predictive value. SPECT yielded a 33.3% (3/9) sensitivity, a 73.1% (19/26) specificity, a 30.0% (3/10) positive predictive value, and a 76.0% (19/25) negative predictive value. On SPECT, decreased perfusion was observed in most of the patients at clipping sites, which might represent post-operative transient abnormal perfusion and should not be read as vasospasm. In conclusion, this mCBF measurement is more accurate than visual interpretation of SPECT for detecting vasospasm.

Structure-affinity relationships of a unique nicotinic ligand: N(1)-dimethyl-N(4)-phenylpiperazinium iodide (DMPP)

DMPP is a well-known nicotinic agonist that does not fit any proposed pharmacophore for nicotinic binding and represents a unique ligand among the hundreds of nicotinic agonists studied in the past decades. A systematic modulation of the chemical structure of DMPP, aimed to establish its structure-affinity relationships, is reported. The research has allowed to identify molecules such as 11c, 13c, 14c, and 28c, with affinities for alpha(4)beta(2) receptors in the low nanomolar range, some 2 orders of magnitude lower than the lead compound. The agonistic properties of the most interesting compounds have been assessed by measuring their analgesic activity on mice (hot-plate test). Another result of the research was the identification of DMPP analogues, such as 3a (K(i) = 90 nM) and 14b (K(i) = 180 nM), that maintain affinity for the central nicotinic receptor when the ammonium function is changed into an aminic one and are therefore possible leads for drug development in neurodegenerative diseases.

Structure-activity relationships and optimisation of the selective MDR modulator 2-(3,4-dimethoxyphenyl)-5-(9-fluorenylamino)-2-(methylethyl) pentanenitrile and its N-methyl derivative

Several ring-substituted derivatives of previously studied MDR inhibitors 2-(3,4-dimethoxyphenyl)-5-(9-fluorenylamino)-2-(methylethyl)pentanenitrile and 2-(3,4-dimethoxyphenyl)-5-[(9-fluorenyl)-N-methylamino]-2-(methylethyl)pentanenitrile have been synthesised and studied with the aim of optimising activity and selectivity. The results show that MDR inhibition is scarcely sensitive to modulation of the electronic properties of the fluorene ring. Even if dramatic improvement was not obtained, one of the compounds (2) showed improved potency and selectivity with respect to the leads and appears to be a better candidate for drug development.

Structure–activity relationships in 2,2-diphenyl-2-ethylthioacetic acid esters unexpected agonistic activity in a series of muscarinic antagonists

As a continuation of previous research on anticholinergic drugs derived from 2,2-diphenyl-2-ethylthioacetic acid, several 5,5-diphenyl-5-ethylthio-2-pentynamines (2-11) were synthetised and their antimuscarinic activity on M(1-4) receptor subtypes was evaluated by functional tests and binding experiments. One of the compounds obtained showed unexpected agonistic activity in functional experiments on M(2) receptors. Since the compound carried a phenylpiperazine moiety, other similar compounds (12-17) were prepared and found to be endowed with similar behaviour. These ligands, although possessing the bulky structure characterising muscarinic antagonists, display agonistic activity at M(2) subtypes while, as expected, behaving as antagonists on M(3) and M(4) subtypes. On M(1) subtypes, they show agonistic activity which, however, is not blocked by atropine. The peculiar pharmacological profile of these compounds is of interest for studying muscarinic receptor subtypes.

Molecular simplification of 1,4-diazabicyclo[4.3.0]nonan-9-ones gives piperazine derivatives that maintain high nootropic activity

Several 4-substituted 1-acylpiperazines, obtained by molecular simplification of 4-substituted 1,4-diazabicyclo[4.3.0]nonan-9-ones, have been synthesized and tested in vivo on the mouse passive avoidance test, to evaluate their nootropic activity. The results show that, apparently, an N-acylpiperazine group can mimic the 2-pyrrolidinone ring of 1,4-diazabicyclo[4.3.0]nonan-9-one, as the compounds of the new series maintain high nootropic activity. Moreover molecular simplification produces more clear-cut structure-activity relationships with respect to the parent series. The mechanism of action also appears to be similar in the two series. In fact, although the molecular mechanism remains to be elucidated, the most potent compound of each class (DM232 and 13, DM235) is able to increase acetylcholine release in rat brain. Piperazine derivatives represent a new class of nootropic drugs with an in vivo pharmacological profile very similar to that of piracetam, showing much higher potency with respect to the reference compound. Among the compounds studied, 13 (DM235) shows outstanding potency, being active at a dose of 0.001 mg kg(-1) sc.

Design, synthesis, and preliminary pharmacological evaluation of 1, 4-diazabicyclo[4.3.0]nonan-9-ones as a new class of highly potent nootropic agents

Several 4-substituted 1,4-diazabicyclo[4.3.0]nonan-9-ones have been synthesized and tested in vivo on mouse passive avoidance test, to evaluate their nootropic activity. The results show that they represent a new class of nootropic drugs with a pharmacological profile very similar to that of piracetam, showing much higher potency with respect to the reference. Among the compounds studied, 7 (DM 232) shows outstanding potency, being active at the dose of 0. 001 mg kg(-1) sc.

Design, synthesis, and in vitro activity of catamphiphilic reverters of multidrug resistance: discovery of a selective, highly efficacious chemosensitizer with potency in the nanomolar range

On the basis of the results obtained in previous research, three series of compounds (A-C), derived from verapamil, were designed and synthesized to obtain drugs able to revert multidrug resistance (MDR), an acquired resistance that frequently impairs cancer chemotherapy. The ability of the obtained compounds to revert MDR was evaluated on anthracycline-resistant erythroleukemia K 562 cells, measuring the uptake of THP-adriamycin (pirarubicin) by continuous spectrofluorometric monitoring of the decrease of the fluorescence signal of the anthracycline at 590 nm (lambdaex = 480 nm), after incubation with cells. Cardiovascular activity, which is responsible for unwanted side effects, was also evaluated. The results obtained show that many of the compounds studied are potent reverters of MDR and are endowed with reduced cardiovascular activity. One of the compounds (7, MM36) presents a pharmacological profile (unprecedented nanomolar potency, high reversal of MDR, low cardiovascular activity) that makes it a promising drug candidate to treat MDR and a useful tool for studying P-glycoprotein.

Hybridized and isosteric analogues of N1-acetyl-N4-dimethyl-piperazinium iodide (ADMP) and N1-phenyl-N4-dimethyl-piperazinium iodide (DMPP) with central nicotinic action

A series of piperazine derivatives, obtained by hybridization of N1-acetyl-N4-dimethyl-piperazinium iodide (1, ADMP) and N1-phenyl-N4-dimethyl-piperazinium iodide (3, DMPP) or of the corresponding tertiary bases (2, 4) with arecoline (5) and arecolone (6) or by isosteric substitution of the phenyl ring of DMPP, has been synthesized. Hybridization afforded compounds that, both as tertiary bases and as iodomethylates, have no affinity for the nicotinic receptor. On the contrary, isosteric substitution gave compounds that maintain affinity for the receptor; among them, two tertiary bases (37, 38), show affinity in the nanomolar range for the nicotinic receptor. The pharmacological profile of these isomeric compounds is quite interesting as they present differences in their peripheral and central effects, suggesting that they interact with different subtypes of the nicotinic receptor.

Further structure-activity relationships in the series of tropanyl esters endowed with potent antinociceptive activity

Several analogs of the alpha-tropanyl esters of 2-(4-chlorophenoxy)butyric acid (SM21) and 2-phenylthiobutyric acid (SM32), endowed with potent antinociceptive and cognition enhancing activity, were synthesized, aimed at obtaining more potent and safe drug candidates. Variation of the acyl moiety (4-11), as well as the conformational restriction of atropine to give the alpha-tropanyl ester of 2,3-dihydrobenzofurane-3-carboxylic acid (18), practically abolished activity. In the case of 18, the antimuscarinic activity was also severely affected by the conformation restrain. On the contrary, conformational restriction of phenoxybutyric and phenylthiobutyric acid derivatives to give the alpha-tropanyl ester of 2,3-dihydro-benzofurane-2-carboxylic acid and 2,3-dihydro-benzothiophene-2-carboxylic acid (12-17), afforded potent analgesic drugs that unfortunately were too toxic to be reliable drug candidates. A series of related esters of benzofurane-3-carboxylic acid (20-27) and benzothiophene-3-carboxylic acid (28) were also studied and found to be potent but toxic analgesics.

In vitro characterization of a novel, potent and selective M3 antagonist

The pharmacological profile of the competitive muscarinic antagonist (2S, 3'R) 3-quinuclidinyl tropate, abbreviated (-)-2a, was evaluated on rabbit vas deferens (M1/M4-like; pA2=9.10), guinea-pig left atrium (M2; pA2=9.30), guinea-pig ileum (M3; pA2=10.33) and guinea-pig uterus (M4 putative; pA2=9.70) muscarinic receptors and on the five subtypes of muscarinic receptors expressed individually in CHO-K1 cells. The drug shows an affinity for the M3 receptor subtype at least 10-fold higher than 4-DAMP, p-HHSiD and zamifenacin, used as reference drugs. These results suggest (-)-2a as a novel, potent and selective M3 antagonist that may have therapeutic potential in the treatment of conditions associated with increased smooth muscle contractility.

SAR studies on the potent and selective muscarinic antagonist 2-ethylthio-2,2-diphenylacetic acid N,N-diethylaminoethyl ester

Molecular modification of the potent and selective muscarinic antagonist 2-ethylthio-2,2-diphenylacetic acid N,N-diethylaminoethyl ester was performed in order to identify M2 selective antagonists able to cross the blood brain barrier and potentially useful in the treatment of Alzheimer's disease. Modifications included substitution or hydrogenation of one of the phenyl rings as well as their incorporation in a tricyclic system. In general the changes introduced were detrimental for both affinity and selectivity. Only a modest M2 selectivity is present in some compounds that, on the other hand, carry a quaternary ammonium group which precludes their penetration into the brain.

Synthesis, characterization and pharmacological profile of tropicamide enantiomers

The synthesis, chemical characterization and antimuscarinic activity of the two enantiomers of tropicamide are reported. Functional (rabbit vas deferens, guinea pig heart (force) and ileum) as well as binding experiments (m1 and m4 human muscarinic receptors expressed in CHO-K1 cells: M2 and M3 receptors of rat heart and submaxillary gland membranes) were used to evaluate the antimuscarinic activity of the enantiomers. The results show that none of the enantiomers is able to significantly discriminate among the receptors studied and therefore do not support the proposal of tropicamide as an M4 (m4) selective agent.

Reduced flexibility analogs of analgesic and cognition enhancing alpha-tropanyl esters

A series of semirigid analogs of compounds 1 and 2, two potent analgesics and cognition enhancers, have been synthesized and tested for antinociceptive activity (hot plate test) and for muscarinic affinity (binding in rat cerebral cortex). They were found to be in general less potent than the reference compounds; only one of them (22) shows a good affinity for the muscarinic receptor and an antinociceptive efficacy comparable with those of the reference compounds. At a dose of 30 mg/kg 22 is also able to reverse the amnesic effect of dicyclomine. Since the analgesic effect of these compounds is affected by the 5-HT4 antagonist SDZ 205557, the possible role of this receptor is discussed.

Chiral synthesis and pharmacological evaluation of the enantiomers of SM32, a new analgesic and cognition-enhancing agent

The enantiomers of 3-alpha-tropyl 2-(phenylthio)butyrate (SM32, 1) were prepared by chiral synthesis and tested for analgesic, cognition-enhancing, and ACh-releasing properties. They show enantioselectivity in some of the tests, the eutomer being related in configuration to R-(+)-hyoscyamine.

Synthesis and enantioselectivity of the enantiomers of PG9 and SM21, new potent analgesic and cognition-enhancing drugs

The enantiomers of two alpha-tropanyl esters, SM21 (1) and PG9 (2), derived from (+)-R-hyoscyamine, that act by increasing the central cholinergic tone, were obtained by esterification after resolution of the corresponding racemic acids [(-)-S-1, (-)-R-2 and (+)-S-2] and by stereospecific synthesis [(+)-R-1]. Their analgesic and cognition-enhancing activities were tested in mice and their ACh-releasing properties determined on rat parietal cortex. These compounds show enantioselectivity in analgesic and cognition-enhancing tests on mice, the eutomers being the isomers which possess the same spatial arrangement of the groups on the chiral atom as (+)-R hyoscyamine [(+)-R-SM21, (+)-S-PG9]. The ACh-releasing effect of the enantiomers of SM21 in rats is in agreement with the results in mice, while PG9 enantiomers do not show any appreciable enantioselectivity in this test. On the basis of the different effects of the 5-HT4 antagonist SDZ 205557 on analgesia induced by the enantiomers of 1 and 2 and by (+)-R-hyoscyamine and the alpha-tropanyl ester of 2-phenylpropionic acid 3, a mechanism of action is proposed for this class of compounds.

Structural dependence of the allosteric interaction of semi-rigid verapamil analogues with dihydropyridine-binding in kitten heart

Structural determinants of the allosteric interaction of semi-rigid verapamil analogues with dihydropyridine binding were investigated in kitten heart using [3H](+)-isradipine as radioligand. Chemical variations were performed in the alkyl chain of verapamil and include introduction of unsaturation (double or triple bonds) or the insertion of cyclohexyl moieties. Introduction of unsaturation generally reduces the allosteric interaction in the case of 'double bond'-and abolishes it in the case of 'triple bond'-derivatives. Also the introduction of cyclohexyl moieties diminishes the potency of allosteric interaction: derivatives with the phenylethylamino side chain in an equatorial position exhibit the allosteric interaction, while it is lacking in derivatives with the basic side chain in axial position. Thus, the reduced conformational flexibility of the new verapamil congeners reduces or abolishes their ability to allosterically interfere with dihydropyridine binding. A molecular interpretation was approached by molecular modelling studies. The strategy was to find low energy conformations common to the active congeners, but not shared by the inactive ones. Structural features discriminating allosterically active and inactive congeners comprise: 1) the position of the nitrogen, 2) the volume occupied by the N-methyl groups, 3) the direction of the N-H bond and 4) the position of the phenyl ring in the basic side chain.

Reversal of multidrug resistance by verapamil analogues

The basic distinguishing feature of multidrug resistant (MDR) cells is a decrease in steady-state drug levels as compared to drug-sensitive controls. It is well-known that verapamil increases the sensitivity of MDR cells to drugs, thus reverting drug resistance. A limiting factor for its clinical use is the pronounced cardiovascular effects of the calcium channel antagonist which occur at the high plasma concentrations required to block P-glycoprotein transport efficiently. From a clinical point of view, it is important to find verapamil derivatives with low calcium channel blocking activity and high reverting activity. This was the aim of the present study. In this context we have investigated the ability of 20 verapamil analogues with restricted molecular flexibility to increase cellular accumulation of anticancer drugs and overcome resistance, and their inotropic, chronotropic, and slow calcium channel antagonistic activity. In this study an anthracycline derivative 4'-O-tetrahydropyranyl adriamycin, and an erythroleukaemia K562 cell line were used. Three of the 20 derivatives checked were completely devoid of calcium channel blocking activity while exhibiting MDR reverting ability comparable to that of verapamil. These derivatives could be useful for the treatment of MDR in cancer patients and for the design and development of other verapamil derivatives.

Analgesic, antimuscarinic activity and enantioselectivity of the four isomers of 3-quinuclidinyl tropate as compared with the enantiomers of hyoscyamine

The four stereoisomers of 3-quinuclidinyl tropate (2) were synthesized and their absolute configuration established. The analgesic activity of the four isomers on the hot-plate test and their muscarinic antagonism on rabbit vas deferens (M1), guinea-pig heart (Force, M2) and ileum (M3) and on the muscarinic receptors present in immature guinea-pig uterus were evaluated. The results were compared with those of the enantiomers of hyoscyamine (1). No apparent correlation was found between the analgesic activity and antimuscarinic activity on M1, M2 and M3 receptors, whereas striking differences exist between the affinity values of the analgesic enantiomer of hyoscyamine (R-(+)-1) and those of the inactive isomers of 2 on the muscarinic receptor present in immature guinea pig uterus. Molecular Modelling studies have shown that the only difference between 1 and 2 lies in the volumes occupied by the basic part of the molecules.

Dialkylaminoalkyl esters of 2,2-diphenyl-2-alkylthioacetic acids: a new class of potent and functionally selective muscarinic antagonists

The synthesis and pharmacological activity as muscarinic antagonists of a number of 2-alkylthio-2,2-diphenylacetic acid esters are reported. The compounds studied are potent muscarinic antagonists and many of them show from moderate to high selectivity toward M2 or toward M1 and M2 receptors when tested on tissues but lack selectivity on five muscarinic human receptors (m1-m5) cloned and expressed in CHO-K1 cells. As a consequence, the compounds behave as functionally selective antagonists. Those showing M2 selectivity appear to be good drug candidates for the treatment of cognitive disorders connected with central cholinergic deficit.

Presynaptic cholinergic modulators as potent cognition enhancers and analgesic drugs. 2. 2-Phenoxy-, 2-(phenylthio)-, and 2-(phenylamino)alkanoic acid esters

Further modifications of the leads ((R)-(+)-hyoscyamine and (p-chlorophenyl)propionic acid alpha-tropanyl ester), which show analgesic and nootropic activities as a consequence of increased central presynaptic ACh release, are reported. 2-Phenoxy- and 2-(phenylthio)alkanoic acid esters showed the best results. Several members of these classes possess analgesic properties which are comparable to that of morphine and at the same time are able to reverse dicyclomine-induced amnesia. Confirmation was found that the mechanism of action is due to an increase in ACh release at central muscarinic synapses and that both auto- and heteroreceptors controlling ACh release are very likely involved. According to the results obtained with (R)-(+)-hyoscyamine, analgesic activity is stereochemistry dependent, since the R-(+)-enantiomers are always more efficacious than the corresponding S-(-)-ones. On the basis of their potency and acute toxicity, compounds (+/-)-28 (SM21) and (+/-)-42 (SM32) were selected for further study.

Presynaptic cholinergic modulators as potent cognition enhancers and analgesic drugs. 1. Tropic and 2-phenylpropionic acid esters

Previous studies have shown that (R)-(+)-hyoscyamine has analgesic activity as a consequence of increased ACh release following antagonism of central muscarinic autoreceptors. Since the enhancement of central cholinergic transmission could be beneficial for cognitive disorders, we manipulated (R)-(+)-hyoscyamine, synthesizing several derivatives of tropic and 2-phenylpropionic acids, with the aim of obtaining drugs which are able to increase ACh release and consequently to show analgesic and nootropic activities. The results showed that several new compounds are indeed potent analgesics (with an analgesic efficacy comparable to that of morphine) and that the most potent one ((+/-)-19, PG9) also has remarkable cognition-enhancing properties. Our study confirmed that the mechanism of action involves ACh release even if it is still unclear whether only muscarinic autoreceptors or, also, heteroreceptors are involved.

1,3-oxathiolane muscarinic ligands modified at the cationic head

In order to develop compounds which may be useful in the treatment of memory and cognitive disorders we have synthesized and tested some 1,3-oxathiolane derivatives bearing an amidine function instead of the classical ammonium head, with the aim of improving brain penetration. The compounds were tested on peripheral and central models of muscarinic receptors. The results show that, unlike for other series of muscarinic ligands, this modification results in the reduced potency of antagonists, shifts the activity of agonists toward weak antagonism and does not introduce any noteworthy subtype selectivity.

Semi-rigid analogues of the calcium antagonist verapamil: a molecular modelling study

In this work the rigid-analogue approach has been used to obtain information on the active conformation(s) of the calcium antagonist verapamil. A series of semi-rigid analogues of verapamil were synthesized and their biological activities evaluated on guinea-pig heart and aorta. These molecules were analysed by means of molecular modelling techniques. On the basis of the pharmacological profile and conformational analysis of these compounds, two different models for negative inotropic and negative chronotropic activity are proposed. The two actions seem to be due to conformations of the molecules which differ in the orientation of their phenylethylamino groups.

Synthesis and biological activity of a series of aryl tropanyl esters and amides chemically related to 1H-indole-3-carboxylic acid endo 8-methyl-8-azabicyclo[3.2.1]oct-3-yl ester. Development of a 5-HT4 agonist endowed with potent antinociceptive activity

A series of aryl tropanyl esters and amides related to 1H-indole-3-carboxylic acid endo 8-methyl-8-azabicyclo[3.2.1]oct-3-yl ester (ICS 205930, CAS 89565-68-4) were synthesized and evaluated for antinociceptive activity using the hot-plate test. Of these, the benzofurane-3-carboxylic ester of tropine (1) was found powerfully to increase the pain threshold, with a cholinergic mechanism of action. Despite the structural similarity with ICS 205930, the analgesia induced by 1 seems not to be due to 5-HT3 receptor interaction, and there is evidence of involvement of the central 5-HT4 receptor.

Verapamil analogues with restricted molecular flexibility: synthesis and pharmacological evaluation of the four isomers of alpha-[1-[3-[N-[1- [2-(3,4-dimethoxyphenyl)ethyl]]-N-methylamino]cyclohexyl]]-alpha- isopropyl-3,4-dimethoxybenzene-acetonitrile

The synthesis and pharmacological activities of the four isomeric racemates of alpha-[1-[3-[N-[1-[2-(3,4-dimethoxyphenyl)ethyl]]-N- methylamino]cyclohexyl]]-alpha-isopropyl-3,4-dimethoxybenzene-acetoni trile are reported (2a-d). The compounds are verapamil analogues with restricted molecular flexibility designed to gather information on the active conformation(s) of the parent drug. The relative stereochemistry of the four racemates was established by X-ray crystallography and by 1H NMR spectroscopy; conformational analysis was supported by theoretical calculations. Negative inotropic and chronotropic activities were evaluated on guinea pig atria, while vasodilatory activity on smooth muscle was tested on guinea pig aortic strips. Binding studies on cat ventricles were performed using (-)-[N-methyl-3H]desmethoxyverapamil (D888) as a reference ligand. The results seem to support the hypothesis that cardiac depressant and vasorelaxant activities are due to different conformations of the verapamil molecule.

Synthesis and cardiovascular properties of fluorenyl derivatives related to verapamil

A series of fluorenyl analogues of verapamil were synthesized and their cardiovascular properties on guinea pig isolated atria and isolated perfused heart evaluated. The compounds were also tested for their calcium antagonistic activity on guinea pig aorta. They were found to be poor calcium antagonists, but showed negative inotropic and antiarrhythmic properties. The results obtained seem to indicate that their mechanism of action differs from that of verapamil.

Verapamil analogues with restricted molecular flexibility

Three analogues with restricted flexibility were designed to study the active conformation of verapamil during interaction with the slow calcium channel. Thus cis- and trans-1-(3,4-dimethoxyphenyl)-4-[N-[2-(3,4-dimethoxy-phenyl)ethyl]-N- methylamino]-r-1-cyclohexanecarbonitrile (5a and 5b), and 4-(3,4-dimethoxyphenyl)-N-[2-(3,4-dimethoxyphenyl)ethyl]-4-cyanopiper idine, in which the verapamil structure is inserted into a cyclohexane or piperidine ring, were synthesized. Conformational analysis was performed with NMR and theoretical methods, and slow calcium channel antagonism was tested on guinea pig aorta strips. The compounds are some 100 times less potent than the parent compound even if they are able to reach conformations that are quite close to the lowest energy conformation proposed for verapamil and similar compounds. It appears that the flexibility to rotate around the bond between the quaternary atom and the adjacent methylene, a property which is lost in compounds 5a, 5b, and 6, is a major requisite for the calcium antagonism of verapamil.