Podophyllotoxin: Recent Advances in the Development of Hybridization Strategies to Enhance Its Antitumoral Profile

Podophyllotoxin is a naturally occurring cyclolignan isolated from rhizomes of Podophyllum sp. In the clinic, it is used mainly as an antiviral; however, its antitumor activity is even more interesting. While podophyllotoxin possesses severe side effects that limit its development as an anticancer agent, nevertheless, it has become a good lead compound for the synthesis of derivatives with fewer side effects and better selectivity. Several examples, such as etoposide, highlight the potential of this natural product for chemomodulation in the search for new antitumor agents. This review focuses on the recent chemical modifications (2017-mid-2023) of the podophyllotoxin skeleton performed mainly at the C-ring (but also at the lactone D-ring and at the trimethoxyphenyl E-ring) together with their biological properties. Special emphasis is placed on hybrids or conjugates with other natural products (either primary or secondary metabolites) and other molecules (heterocycles, benzoheterocycles, synthetic drugs, and other moieties) that contribute to improved podophyllotoxin bioactivity. In fact, hybridization has been a good strategy to design podophyllotoxin derivatives with enhanced bioactivity. The way in which the two components are joined (directly or through spacers) was also considered for the organization of this review. This comprehensive perspective is presented with the aim of guiding the medicinal chemistry community in the design of new podophyllotoxin-based drugs with improved anticancer properties.

Effect of vacuum impregnation on physical changes during table olive processing

Among the benefits which vacuum impregnation (VI) may provide to fruits and vegetables, this study focused on weight and texture changes during the processing of table olives. VI applied to Manzanilla olives led to around 10% weight gain, which was maintained after their packing as black olives. However, this weight gain was only around 4 % for Hojiblanca olives. Likewise, the use of calcium chloride was recommended to maintain the firmness of the olives, in particular those of the softer Manzanilla cultivar. With regard to the Spanish-style, the Hojiblanca cultivar achieved around 4% weight gain during processing but the use of VI for Manzanilla olives was ruled out due to softening of the fruit. In addition. the black and green color of olives and their flavor were not modified by the application of VI. This technology could be very useful to reduce weight loss during table olive processing.

Incertidumbre y afrontamiento en familiares de personas dependientes del alcohol: apoyo social y espiritualidad

Introducción: La dependencia al alcohol, considerada como una enfermedad crónica, es un detonante de incertidumbre para el familiar de la persona con dependencia, lo cual genera trastornos emocionales negativos. El apoyo social y la espiritualidad son mecanismos de afrontamiento que podrían disminuir la incertidumbre y favorecer el bienestar tanto físico, como psicológico. Objetivos: Determinar la relación y el efecto del apoyo social y la espiritualidad sobre la incertidumbre del familiar de la persona dependiente del alcohol. Métodos: Estudio descriptivo y correlacional, muestra de 135 mujeres pertenecientes a grupos Al-Anon, se utilizaron la Escala de Percepción de Incertidumbre en Padres y Miembros de la Familia (PPUS-FM) de Mishel, el cuestionario MOS-SSS de Sherbourne y Stewart y la Escala de Perspectiva Espiritual elaborada por Reed. Resultados: Se identificó un coeficiente de correlación negativo y significativo de la incertidumbre con el apoyo social (rs= -.356, p <.01) y la espiritualidad (rs= -.216, p <.05). Mediante un modelo de regresión lineal general univariado se determinó que únicamente el apoyo social influye en la disminución de la incertidumbre (β= -.280, t= -3.62, p= .001) con un coeficiente de determinación o varianza explicada del 11.5%, mientras que la espiritualidad no mostró efecto (β= -.041, t= .218, p >.05) sobre la incertidumbre. Conclusiones: El apoyo social es identificado como un mecanismo de afrontamiento efectivo que permitirá al personal de enfermería desarrollar intervenciones dirigidas a reducir la incertidumbre en familiares de personas con algún tipo de dependencia.

Zr-MOF-808 as Catalyst for Amide Esterification

In this work, zirconium-based metal-organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.

Zr-MOF-808@MCM-41 catalyzed phosgene-free synthesis of polyurethane precursors

Zr-MOF-808@MCM-41 exhibited high catalytic activity, selectivity and stability for the synthesis of aromatic carbamates from aromatic amines and dimethyl carbonate.

Catalytic Transfer Hydrogenation of Biomass-Derived Carbonyls over Hafnium-Based Metal-Organic Frameworks

A series of highly crystalline, porous, hafnium-based metal-organic frameworks (Hf-MOFs) have been shown to catalyze the transfer hydrogenation reaction of levulinic ester to produce γ-valerolactone by using isopropanol as a hydrogen donor. The results are compared with their zirconium-based counterparts. The role of the metal center in Hf-MOFs has been identified and reaction parameters optimized. NMR studies using isotopically labeled isopropanol provide evidence that the transfer hydrogenation occurs through a direct intermolecular hydrogen transfer route. The catalyst, Hf-MOF-808, can be recycled several times with only a minor decrease in catalytic activity. The generality of the procedure has been demonstrated by accomplishing the transformation with aldehydes, ketones, and α,β-unsaturated carbonyl compounds. The combination of Hf-MOF-808 with the Brønsted-acidic Al-Beta zeolite gives the four-step one-pot transformation of furfural to γ-valerolactone in good yield of 75 %.

Psychiatric Comorbidity at the Time of Diagnosis in Adults With ADHD: The CAT Study

OBJECTIVE

The CAT (Comorbilidad en Adultos con TDAH) study aimed to quantify and characterize the psychiatric comorbidity at the time of diagnosis of ADHD in adult outpatients.

METHOD

Cross-sectional, multicenter, observational register of adults with ADHD diagnosed for the first time.

RESULTS

In this large sample of adult ADHD (n = 367), psychiatric comorbidities were present in 66.2% of the sample, and were more prevalent in males and in the hyperactive-impulsive and combined subtypes. The most common comorbidities were substance use disorders (39.2%), anxiety disorders (23%), and mood disorders (18.1%). In all, 88.8% patients were prescribed pharmacological treatment for ADHD (in 93.4% of cases, modified release methylphenidate capsules 50:50).

CONCLUSION

A high proportion of psychiatric comorbidity was observed when adult outpatients received a first-time diagnosis of ADHD. The systematic registering of patients and comorbidities in clinical practice may help to better understand and manage the prognostic determinants in adult ADHD.

Quo Vadis Clozapine? A Bibliometric Study of 45 Years of Research in International Context

We have carried out a bibliometric study about the international scientific publications on clozapine. We have used the EMBASE and MEDLINE databases, and we applied bibliometric indicators of production, as Price's Law on the increase of scientific literature. We also calculated the participation index (PI) of the different countries. The bibliometric data have also been correlated with some social and health data from the 12 most productive countries in biomedicine and health sciences. In addition, 5607 original documents dealing with clozapine, published between 1970 and 2013, were downloaded. Our results state non-fulfilment of Price's Law, with scientific production on clozapine showing linear growth (r=0.8691, vs. r=0.8478 after exponential adjustment). Seven of the 12 journals with the highest numbers of publications on clozapine have an Impact Factor>2. Among the countries generating clozapine research, the most prominent is the USA (PI=24.32), followed by the UK (PI=6.27) and Germany (PI=5.40). The differences among countries on clozapine research are significantly related to economic variables linked to research. The scientific interest in clozapine remains remarkable, although after the application of bibliometric indicators of production, a saturation point is evident in the growth of scientific literature on this topic.

Risk-benefit analysis of antidepressant drug treatment in the elderly

Depression in the elderly is a significant health issue that has the potential to seriously affect physical and emotional well-being. Therefore, the treatment of geriatric depression is necessary. Antidepressant treatment in older depressed patients is efficacious, but differences in the effectiveness of different classes of antidepressants have not been demonstrated. However, differences in tolerability profile are most recognizable in the elderly. With ageing, a series of changes occur in the elderly that modify both the pharmacokinetics and pharmacodynamics of antidepressants and may influence the efficacy, tolerability and safety of treatment in the elderly. Comorbidities require the use of other drugs, which increases the possibility of drug-drug interactions. Given these aspects, individualized therapy for each elderly patient is needed to achieve acceptable risk-benefit ratio. Effective treatment of depression in the elderly, which may require combined pharmacological with psychosocial treatment, can decrease both morbidity and mortality; it also may lead to reduced demands on family members and on health-care and social services.

Fortification of table olive packing with the potential probiotic bacteria Lactobacillus pentosus TOMC-LAB2

Dairy products are currently the main carriers of probiotic microorganisms to the human body. However, the development of new matrices for probiotic delivery is convenient for intolerant to milk (or its derivatives) and those requiring low-cholesterol diet consumers. The present work focused on the fortification of previously fermented green Spanish style olives with the autochthonous putative probiotic bacteria Lactobacillus pentosus TOMC-LAB2. The fortification was carried out by inoculating the bacteria into the packing brines using Manzanilla fruits from three different processes: (i) spontaneously fermented (F1), (ii) fermented using L. pentosus TOMC-LAB2 as starter (F2), and (iii) spontaneously fermented and then thermally treated (F3). Data showed that all inoculated treatments had higher population levels (5.49, 4.41, and 6.77 log₁₀ cfu/cm²) than their respective controls (1.66, 4.33, and 0.0 log₁₀ cfu/cm², for F1, F2, and F3 treatments, respectively). The presence of L. pentosus TOMC-LAB2 on olive surface was confirmed by rep-PCR, with a recovery frequency at the end of the shelf life (200 days) of 52.6, 57.9, and 100.0% for F1, F2, and F3 treatments, respectively. Thus, results obtained in this work show the ability of this microorganism to survive under packing conditions for long period of times as well as to colonize the olive surface which is the food finally ingested by consumers. This opens the possibility for the development of a new and simply probiotic fortified olive product.

Mapping the scientific research on atypical antipsychotic drugs in Spain: a bibliometric assessment

OBJECTIVES

We carried out a bibliometric study on the scientific publications in relation to atypical antipsychotic drugs (AADs) in Spain.

METHODS

We used the EMBASE and MEDLINE databases and we applied some bibliometric indicators of paper production and dispersion (Price's law and Bradford's law, respectively). We also calculated the participation index of the different countries and correlated the bibliometric data with some social and health data (total per capita expenditure on health and gross domestic expenditure on research and development).

RESULTS

We collected 656 original papers published between 1988 and 2011. Our study results fulfilled Price's law with scientific production on AADs showing exponential growth (correlation coefficient r = 0.9693, vs. r = 0.9177 after linear adjustment). The most widely studied drugs were risperidone (181 papers), olanzapine (143), clozapine (94), and quetiapine (74). Division into Bradford zones yielded a nucleus occupied by the European Psychiatry and European Neuropsychopharmacology (70 articles). Totally 194 different journals were published, with 5 of the first 10 used journals having an impact factor being greater than 4.

CONCLUSION

The publications on AADs in Spain have undergone exponential growth over the studied period, without evidence of reaching a saturation point.

Microbial stability and quality of seasoned cracked green Aloreña table olives packed in diverse chloride salt mixtures

This work was conducted to determine the effect of the partial replacement of NaCl by KCl and CaCl2 (expressed as percentages, wt/vol) on the microbial stability and physicochemical characteristics of seasoned cracked olives using a simplex centroid mixture design. Neither Enterobacteriaceae nor lactic acid bacteria were found during the 50 days that olive packages were monitored. Therefore, microbial instability was considered due to the growth of yeasts, which were the only detected microorganisms; Saccharomyces cerevisiae and Pichia membranifaciens were the most relevant species. Yeasts decreased during the first 21 to 30 days after packing, but their populations rose to 3.5 log CFU/ml by the end of the storage period, clearly causing product deterioration. The partial substitution of NaCl with the other chloride salts slightly altered the phase of microbial inhibition and regrowth. Most of the quality characteristics were not affected by the use of the alternative salt mixtures, but the pH values and Cl(-) concentrations in brine decreased as the CaCl2 concentration increased. Hence, seasoned cracked table olives can be produced using a lower proportion of NaCl without causing significant changes in the shelf life and product quality, although further detailed studies are necessary to guarantee the stability of products packed with specific salt mixtures.

Lanthanum Carbonate Modulates Inflammatory Profile in Hemodialysis Patients: Relationship with Fibroblast Growth Factor-23

Elevated fibroblast growth factor 23 (FGF-23) is independently associated with increased inflammatory markers in chronic kidney disease. Lanthanum carbonate (LaCa) reduces FGF-23. We studied the effects of LaCa on inflammatory profile of hemodialysis patients, and the relationship with changes in FGF-23. This prospective study was performed under habitual clinical practice conditions. Twenty-six hemodialysis patients with serum phosphate > 5 mg/dl receiving calcium-based phosphate binders were switched to LaCa. Ten patients with phosphate ≤ 5 mg/dl under calcium-based phosphate binders were enrolled as a control group for comparison. Serum calcium, phosphorus, calcium-phosphate product (CaxP), intact parathyroid hormone and the inflammatory profile [including serum high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-10, as well as mRNA expression levels of TNF-α and IL-6 in peripheral blood mononuclear cells] were analyzed. Serum FGF-23 significantly decreased in patients switched to LaCa (P< 0.01), with a concomitant reduction in serum hsCRP (-10.9%, P < 0.01), TNF-α (-6.7%, P < 0.05) and IL-6 (-8.1%, P < 0.01). mRNA expression levels of TNF-α and IL-6 in PBMC also decreased by 7.8% (P< 0.05) and 10.3% (P< 0.01), respectively. Multivariate regression analysis demonstrated that variations in FGF-23 were the only independent determinant of the changes in serum and mRNA expression levels of inflammatory parameters. In conclusion, LaCa posses anti-inflammatory actions, which are significant and independently associated with the reduction of FGF-23. FGF-23 may regulate inflammatory cytokine gene expression at the transcriptional level. Whether these effects have influence on clinical outcomes warrants consideration.

Evaluating the individual effects of temperature and salt on table olive related microorganisms

Statistical modelling techniques were used in the present study to assess the individual effects of temperature and NaCl concentration on the growth of 10 lactic acid bacteria and 6 yeast strains mostly isolated from different forms of table olive processing and belonging to the species Lactobacillus pentosus, Lactobacillus plantarum, Saccharomyces cerevisiae, Wickerhamomyces anomalus and Candida boidinii. The mathematical models obtained in synthetic laboratory media show that yeasts, except for C. boidinii, were more resistant to a high salt concentration than lactic acid bacteria, with an MIC value ranging from 163.5 (S. cerevisiae) to 166.9 g/L (W. anomalus); while for L. pentosus and L. plantarum this parameter ranged from 110.6 to 117.6 g/L, respectively. With regards to temperature, lactic acid bacteria showed a slight trend towards supporting higher temperature values than yeasts, with the exception of S. cerevisiae. The maximum temperatures for growth of L. pentosus and L. plantarum were 41.9 and 43.0 °C, respectively; while for W. anomalus and C. boidinii they were 38.2 and 36.5 °C. The optimum temperatures for growth were also higher for L. pentosus and L. plantarum (35.5 and 32.9 °C), compared to W. anomalus and C. boidinii (29.3 and 26.9 °C, respectively). Additional experiments carried out in natural olive brines confirmed previous results, showing that high NaCl concentrations clearly favoured yeast growth and that at high temperatures LAB slightly overcame yeasts. Results obtained in this paper could be useful for industry for a better control of both table olive fermentation and packaging.

Yeasts in table olive processing: desirable or spoilage microorganisms?

Yeasts are unicellular eukaryotic microorganisms isolated from many foods, and are commonly found in table olive processing where they can play a double role. On one hand, these microorganisms can produce spoilage of fruits due to the production of bad odours and flavours, the accumulation of CO(2) leading to swollen containers, the clouding of brines, the softening of fruits and the degradation of lactic acid, which is especially harmful during table olive storage and packaging. But on the other hand, fortunately, yeasts also possess desirable biochemical activities (lipase, esterase, β-glucosidase, catalase, production of killer factors, etc.) with important technological applications in this fermented vegetable. Recently, the probiotic potential of olive yeasts has begun to be evaluated because many species are able to resist the passage through the gastrointestinal tract and show beneficial effects on the host. In this way, yeasts may improve consumers' health by decreasing cholesterol levels, inhibiting pathogens, degrading non assimilated compounds, producing antioxidants and vitamins, adhering to intestinal cells or by maintaining epithelial barrier integrity. Many yeast species, usually also found in table olive processing, such as Wicherhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens and Kluyveromyces lactis, have been reported to exhibit some of these properties. Thus, the selection of the most appropriate strains to be used as starters, alone or in combination with lactic acid bacteria, is a promising research line to develop in a near future which might improve the added value of the commercialized product.

Formation of lactic acid bacteria-yeasts communities on the olive surface during Spanish-style Manzanilla fermentations

This work examines the formation of poly-microbial communities adhered to the surface of Manzanilla olive fruits processed according to the Spanish style. The experimental design consisted of four pilot fermenters inoculated with four Lactobacillus pentosus strains, plus another fermenter which was not inoculated and fermented spontaneously. Lactic acid bacteria and yeasts were analysed in depth on olive epidermis throughout fermentation by plate count, molecular techniques and scanning electron microscopy. Data show that in all cases high population levels (above 8 log(10) CFU per olive) were reached for both groups of microorganisms at the second week of fermentation and that these counts never fell below 6 log(10) CFU per olive during the 3 months that fermenters were monitored. In situ observation of olive epidermis slices revealed a strong aggregation and adhesion between bacteria and yeasts by the formation of a matrix which embedded the microorganisms. Geotrichum candidum, Pichia galeiformis and Candida sorbosa were the main yeast species isolated from these biofilms at the end of fermentation (confirmed by RFLP analysis of the 5.8S-ITS region), while molecular characterization of lactobacilli isolates by means of RAPD-PCR with primer OPL(5) showed in many cases a high similarity in their banding profiles with the inoculated strains. Results obtained in this survey show the importance of studying the olive epidermis throughout fermentation, because ultimately, olives are ingested by consumers.

The discovery of chlordiazepoxide and the clinical introduction of benzodiazepines: half a century of anxiolytic drugs

The clinical introduction of chlordiazepoxide half a century ago was one of the major breakthroughs in the history of psychopharmacology, as it opened the door for the benzodiazepine saga, the pharmacological family par excellence in the treatment of anxiety disorders. This review analyses the discovery of this drug, which was filled with chance events, and numerous chemical and clinical errors of approach. Chlordiazepoxide, initially called methaminodiazepoxide, was patented in 1958 and introduced in clinical treatment in 1960 under the brand name Librium®. The benzodiazepines became the most widely prescribed drugs worldwide, provided truly effective treatment for "minor forms" (neuroses) of mental disorders for the first time, increased the quality of scientific methodology in clinical research, and enabled the development of new etiopathogenic theories for anxiety disorders, especially after the discovery in 1977 of their high-affinity receptor complex.

Effects of adjunctive reboxetine in patients with duloxetine-resistant depression: a 12-week prospective study

The efficacy of the combination therapy with two antidepressants from different pharmacological families in patients with treatment-resistant depression has been reported in multiple studies. In this prospective 12-weeks open-label study, we assessed the effectiveness of the addition of reboxetine to 79 depressive outpatients diagnosed with major depressive disorder (MDD) according to the DSM-IV criteria who had previously not responded, or had done so only in a partial way, over 8 weeks of conventional treatment, in monotherapy, with duloxetine. Efficacy was assessed using the 21-item Hamilton Depression Rating Scale (HDRS) and the Clinical Global Impression-Improvement (CGI-I). Safety was evaluated by recording spontaneously reported adverse events. Data were analysed on an intent-to-treat basis, using the last-observation-carried-forward method. Mean HDRS reduction was 65.5% (P < 0.0001). The percentages of responders (>or=50% reduction in HDRS) and patients considered benefiting from complete remission (HDRS <or= 10 points) at week 12 were 76% and 69.3%, respectively. By the end of the treatment, the score of CGI-I decreased 68.5% (P < 0.0001). Percentage of patient improving (CGI < 4 points) was 95.8%. The most common non-serious adverse events were dry mouth, increased sweating, constipation and difficulty passing urine. The results of this study suggest that the combination strategy with reboxetine may be an effective and well-tolerated tool in duloxetine-resistant patients.

The role of psychopharmacology in the medical abuses of the Third Reich: from euthanasia programmes to human experimentation

German psychiatry and pharmacology both enjoyed an extraordinary international reputation prior to the promulgation of the Third Reich. However, with the triumph of eugenic ideas and the imposition of a "racial hygiene" policy by the Nazi regime, various organs of the German health system saw themselves involved in a perverse system of social control, in which the illicit use of psychopharmacological tools became customary. In the present work, we review, from the historical perspective, the factors that helped to bring about this situation and we analyze the abuses (known and documented) committed through the specific use of psychotropic drugs during the Nazi period. Among such abuses we can identify the following illegitimate activities: the use of psychoactive drugs, mainly sedatives from the barbiturates family, in the different euthanasia programmes implemented by the Nazi authorities, in police activity and various types of repression, and for purely criminal and extermination purposes within the so-called "Final Solution"; psychopharmacological research on the mentally ill, without the slightest ethical requirements or legal justification; and the use of psychotropic agents in research on healthy subjects, recruited from concentration camps. Finally, we refer to the role of poisonous nerve agents (tabun, sarin and soman) as instruments of chemical warfare and their development by the German authorities. Many of these activities, though possibly only a small portion of the total - given the destruction of a great deal of documentation just before the end of World War II - came to light through the famous Nuremberg Trials, as well as through other trials in which specific persons were brought to justice unilaterally by individual Allied nations or by the authorities of the new German government after the War.

Phytotherapy and psychiatry: bibliometric study of the scientific literature from the last 20 years

In diverse areas of therapy, including psychiatry, increasing interest in herbal medicine has been shown in recent years. Plants have a wide range of traditional uses, but only a few have been approved therapeutically. Moreover, to our knowledge, no bibliometric analyses on medicinal plants used in psychiatry have been carried out to date. We performed a bibliometric study on scientific publication related to phytotherapy in the psychiatry area during the period 1986-2006. Using the platform Embase.com, including the EMBASE and MEDLINE databases, we selected those documents including the descriptors plant*, herb*, phytotherapy*, phytomedicine*, pharmacognosy*, and psychiatry* (with all diagnostic criteria). The plants' indications were selected according to the PDR for Herbal Medicines. As a bibliometric indicator of the production, Price's Law was applied. Another indicator included was the national participation index (PI) for overall scientific production. A total of 21,409 original documents were obtained. Our data confirm a fulfillment of Price's Law related to scientific production on medicinal plants in Psychiatry. This was observed after we made a linear fit (y=135.08x-466.38; r=0.92) and another fit to an exponential curve (y=132.26e(0.1497x); r=0.99). The plants most widely mentioned in the psychiatric literature were St. John's wort (Hypericum perforatum L.; n=937) and ginkgo (Ginkgo biloba L.; n=694). The countries with the highest percentages of documents were the United States (29.44%), Germany (9.41%) and Japan (8.75%), and those with highest proportional PI were India (IPa=0.935) and China (IPa=0.721). Productivity on medicinal plants in the psychiatry area increased during the period 1986-2006. Nevertheless, documents about therapeutic herbs in this medical field are still relatively few in number.

[The development of neurotoxic agents as chemical weapons during the National Socialist period in Germany]

INTRODUCTION

The discovery and development of the so-called 'nerve agents' (neurotoxic substances to be used as weapons) took place in the Third Reich, largely thanks to the vast amount of progress being made in pharmacology in Germany at that time, both in academic and industrial terms. Furthermore, successive National Socialist governments set up a collaborative network made up of the academia, the chemical industry and military chiefs that also favoured this line of research.

DEVELOPMENT

The first neurotoxic substance to be incorporated into the category of 'chemical warfare agent' did so almost wholly by chance. As part of the work being carried out on organophosphate-type pesticides and insecticides, Gerald Schrader, a chemist at the I.G. Farben company, synthesised tabun (ethyl N,N-dimethylphosphoramidocyanidate) and an incident involving accidental contamination of laboratory staff with this substance highlighted its potential toxicity. The same group of researchers later synthesised another substance with the same properties, sarin (isopropyl methylphosphonofluoridate). Both agents were studied for use as chemical weapons by Wolfgang Wirth. At the same time, a group led by Richard Kuhn, who won the Nobel Prize in Chemistry in 1938, synthesised pinacolyl methylphosphonofluoridate, otherwise known as soman.

CONCLUSIONS

Pharmacological studies confirmed that the neurotoxic mechanism of action of these substances was the irreversible inhibition of the enzyme acetylcholinesterase, which is responsible for metabolising acetylcholine. Results also showed that an excess of this neurotransmitter led to a continuous over-stimulation of the cholinergic (nicotinic and muscarinic) receptors, which is what triggers the appearance of the wide range of symptoms of poisoning and their swift fatal effect.