COVID-19 lockdown, personal protective equipment, hyper-hygiene and allergy

Summary

At the beginning of SARS-CoV 2 pandemic, in the absence of "targeted" therapies, the national health authorities have introduced some measures aimed at reducing the spread of infection in the community (lockdown, social distancing, personal protective equipment (PPE), personal hygiene and disinfection of living environments). All the containment measures have led to both positive and negative effects in patients with allergic diseases. We believe that further studies should be undertaken to investigate the possible correlations between SARS-CoV-2 infection and allergy, from a broader perspective. In particular, the risk factors for the development of undesirable effects should be investigated, especially in healthcare professionals forced to use PPE and sanitizing agents for a long time. However, since the COVID-19 pandemic probably will not be short-lived, the use of such protective aids will necessarily be widespread even in the general population. Therefore, further studies on the materials used for the production of PPE and sanitizing agents would be necessary to reduce their sensitizing and, in some cases, toxic potential.

Lessons from peculiar cases of anaphylaxis: why allergists should be prepared for the unexpected

Summary

Anaphylaxis is the most severe systemic hypersensitivity reaction, it can be caused by a number of well identified triggers such as foods, drugs, stinging insects and facilitated by predisposing clinical conditions. However, sometimes anaphylaxis shows up with uncommon or peculiar characteristics which could delay diagnosis and therapeutic treatment. In this report we aimed to describe less accounted / difficult-to-approach shapes of anaphylaxis to facilitate clinicians to suspect these severe reactions even in uncommon conditions. We choose to present data on anaphylaxis regarding simulation, mode of exposure to sensitizing agents, pregnancy, exposure to animals, intimate behaviour, psychological stress and other situations.

Synergy across the drugs approved for the treatment of asthma

INTRODUCTION

Inhaled corticosteroids are the cornerstone for the treatment of stable asthma, however, when disease severity increases, escalating therapy to combinations of drugs acting on distinct signalling pathways is required. It is advantageous to providing evidence of a synergistic interaction across drug combinations, as it allows optimizing bronchodilation while lowering the dose of single agents. In the respiratory pharmacology field, two statistical models are accepted as gold standard to characterize drug interactions, namely the Bliss Independence criterion and the Unified Theory. In this review, pharmacological interactions across drugs approved for the treatment of asthma have been systematically assessed.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for studies that used a validated pharmacological method for assessing drug interaction. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 45 studies were identified from literature search and 5 met the inclusion criteria. Current evidence coming from ex vivo models of asthma indicates that drug combinations modulating bronchial contractility induce a synergistic bronchorelaxant effect. In murine models of lung inflammation, the combination between inhaled corticosteroids and β2- adrenoceptor agonists synergistically improve lung function and the inflammatory profile.

CONCLUSIONS

There is still limited knowledge regarding the mechanistic basis underlying pharmacological interactions across drugs approved for asthma. The synergism elicited by combined agents is an effect of class. Specifically designed clinical trials are needed to confirm the results coming from preclinical evidence, but also to establish the minimal dose for combined agents to induce a synergistic interaction and maximize bronchodilation.

Experimental Glucocorticoid Receptor Agonists for the Treatment of Asthma: A Systematic Review

Inhaled corticosteroids (ICSs) are considered the cornerstone of asthma treatment. Despite the solid evidence documenting the efficacy and safety of ICSs at the level of the airways, their use can be affected by pulmonary and systemic adverse events (AEs) when administered chronically and/or at high doses. Thus, there is a pharmacological and medical need for new glucocorticoid (GC) receptor (GR) ligands with a more favorable therapeutic index, in order to overcome the shortcomings of currently available ICSs. The therapeutic profile of GCs can be improved by enhancing genomic mechanisms mediated by transrepression, which is assumed to be responsible for several anti-inflammatory and immunomodulatory actions, rather than transactivation, which causes most of the GC-associated AEs. It was assumed that an independent modulation of the molecular mechanisms underlying transactivation and transrepression could translate into the dissociation of beneficial effects from AEs. Therefore, current research is looking for GCs that are able to elicit prevalently transrepression with negligible transactivating activity. These compounds are known as selective glucocorticoid receptor agonists (SEGRAs). In this review, experimental GR agonists currently in pre-clinical and clinical development for the treatment of asthma have been systematically assessed. Several compounds are currently under pre-clinical development, but only three novel experimental GR agonists (GW870086X, AZD5423, AZD7594) seem to have some potential therapeutic relevance and have entered clinical trials for the treatment of asthma. Since data from pre-clinical studies have not always been confirmed in clinical investigations, well-designed randomized controlled trials are needed in asthmatic patients to confirm the potentially positive benefit/risk ratio of each specific SEGRA and to optimize the development strategy of these agents in respiratory medicine.

Influence of age on enzyme activities of pyrimidine metabolism in the chicken heart

The effect of the aging on the activities of enzymes involved in UMP-CMP metabolism were evaluated in the heart of newborn (1-day-old), young (20-day-old), adult (12-month-old), and aged (30-month-old) chickens. In newborn animals, UMP metabolism proceeds preferentially towards cytidine compounds rather than to breakdown. In addition, two pathways different from those involved in de novo synthesis may contribute to the synthesis of UMP: one, through cytosine deaminase that shows its maximal activity; the other, by uridine kinase, the main "salvage" enzyme of pyrimidine nucleotides. In young chickens, pyrimidine metabolism regards especially UMP. In fact, the lower activities of cytidylate phosphatase and cytosine deaminase, together with the remarkable increase of uridine kinase indicate that the metabolic flux converges on the main salvage pathway. In adult chickens, pyrimidine catabolism is enhanced, as supported by the maximal activity of the enzymes involved in UMP-CMP breakdown. On the contrary, the remarkable reduction of the anabolic enzymes suggests a limited resort to the salvage pathways. Finally, in aged chickens a reduced pyrimidine catabolism and a greater utilization of the salvage pathways appear to take place, thus contributing to the maintenance of pyrimidine nucleotide pool.

Racial variations in cesarean section rates: an analysis of Medicaid data in Louisiana

The objective of this study was to investigate racial variation in cesarean section rates among Medicaid beneficiaries in Louisiana. Results indicate that over a three-year period, white women had higher rates than women of other races when stratified by age, locality, accompanying diagnoses, and hospital ownership. Comparing Louisiana Medicaid data with birth certificate records, rates among all births were slightly higher than Medicaid births, with the same racial trend. These variations imply significant differences in costs and reimbursement to providers and raising questions about efficiency of current obstetric practices in Louisiana. Implications for a managed care system are discussed.

Enzymes involved in guanine monophosphate metabolism of aging chicken heart

The activities of enzymes involved in GMP metabolism were studied in the heart of aging chickens. In newborn (1-day-old) animals, GMP breakdown apparently leads to the final products of purine metabolism, as the activity of hypoxanthine-guanine phosphoribosyl-transferase (HGPRT), the salvage enzyme of GMP is not detectable. On the contrary, HGPRT shows maximal activity in young (20-day-old) chickens, when xanthine oxidase activity is very low, indicating that the metabolic flux converges on the salvage pathway. Again, maximal activity of the catabolic enzymes and a limited resort to the salvage pathway characterize GMP metabolism of adult (12-month-old) hearts. Finally, in aged (30-month-old) chickens, a reduced GMP catabolism and a greater utilization of the salvage pathway might contribute to the maintenance of the guanine nucleotide pool. In conclusion, the pattern of the activities of enzymes relating to GMP metabolism in the aging heart, compared to AMP metabolism, indicates a parallel temporal regulation of the purine pathways.

Changes of glycosaminoglycan composition in aging chicken brain. A preliminary investigation

The qualitative and quantitative pattern of GAGs was examined by electrophoresis in aging chicken brain in four different stages starting from day 1 to 30 months. GAG content referred to defatted dry tissue exhibits constant decrease. Four main GAGs have been identified with a mobility corresponding to hyaluronate, condroitin sulfate, heparan sulfate and dermatan sulfate controls. Hyaluronate appears the main GAG represented while dermatan sulfate the minor one. Our data show that in chicken brain GAG percentage undergoes age-related changes.

Pathways of adenine nucleotide metabolism: degradation and resynthesis of IMP in ageing chicken heart

The activities of enzymes involved in adenine nucleotide metabolism and the concentration of their metabolic products were studied in the hearts of chickens from birth to advanced age. In particular, in order to investigate the main mechanisms which contribute to ensure availability of adenine nucleotides during ageing of the heart, IMP concentration and the activities of enzymes involved in its turnover were studied. In newborn animals, AMP degradation, though limited in amount, was found to lead to the final products of purine metabolism. In fact, the activity of hypoxanthine phosphoribosyl-transferase (HPRT)-the salvage enzyme of IMP-was not detected. On the contrary, in young chickens, the low concentration of final products of purine metabolism, together with a remarkable activity of HPRT and a high concentration of IMP, indicates that metabolic flux converges on the salvage pathway. In adult chickens, an increase of purine catabolism was observed. This, together with an optimal concentration of endogenous adenine nucleotides, is indicative of a particularly high AMP metabolism. Finally, in chickens of advanced age, a reduced purine catabolism appeared to take place, thus contributing to the maintenance of the adenine nucleotide pool. In ageing heart, a major role of IMP turnover probably consists in the preservation of adenine nucleotides and in the recovery of high-energy phosphates.

Age-related changes of AMP breakdown in chicken heart

The activity of adenylate deaminase, adenylate phosphatase and adenosine deaminase, as well as the endogenous content of adenine nucleotides, was examined in the heart of ageing chickens. In new-born (1-day-old) and young (20-day-old) chickens, AMP degradation in the heart seems to proceed preferentially through deamination, while in adult (1-year-old) through dephosphorylation. Compared with the adult heart, a 2-year-old one exhibits a decline of AMP catabolism. The total adenine nucleotide content and the concentration of ATP are higher in adult and aged chicken hearts, than in new-born and young ones. Adaptive mechanisms might occur in the heart of ageing chickens to ensure an adequate availability of adenine nucleotides.

Enzymes of pyrimidine metabolism in the musculus complexus of the chick during development

The pattern of cytidylate and uridylate phosphatase, uridine phosphorylase, cytidine and cytosine deaminase activities has been studied in M. complexus during chick development. The comparison of these enzyme activities with thigh muscles ones has shown that quantitative and temporal changes occur, in parallel with the unusual pre-natal and early post-natal development of M. complexus. The results suggest that during the first period of incubation, UMP might follow the anabolic pathway UMP-UTP, which leads to cytidine nucleotides, while approaching the hatching, the catabolic pathway should prevail. In addition, immediately after hatching, pyrimidine metabolism is especially supported by cytidine nucleotides.

Studies of pyrimidine metabolism during chick development: two enzymes involved in UMP breakdown

The pattern of uridylate phosphatase and uridine phosphorylase has been studied in the liver, brain, heart and thigh muscles of the chick during development. The study of enzymes involved in pyrimidine metabolism confirms that differences in utilisation of the metabolic pathways exist during ontogenesis. In the liver, starting from the 12th day, an active metabolic pathway, leading to UMP via cytosine should be added to the catabolic ones. In the brain, the second period of embryogenesis should be characterized by a lower utilisation of the catabolic pathways and by an increase of the anabolic ones. In the heart, pyrimidine metabolism during development regards especially UMP. In skeletal muscle, pyrimidine metabolism shows low activity.

Developmental change in the glycosaminoglycan composition of the chick embryo brain

GAGs content was examined in chick embryo brain starting from the 9th day of incubation to the 4th post-hatching day. Chondroitin 6-sulfate, hyaluronate and heparan sulfate were recovered at any developmental stage examined. C6-S was the main GAG (except on the 15th day), while HS was the least represented. The highest differences in the relative amounts of GAGs are observed on the 9th day. C6-S shows high developmental relative changes, while HA and HS exhibit a similar pattern.

[Quantitative and qualitative variations in the glycoproteins in the chick embryo brain]

Sugar content was examined in soluble and insoluble glycoproteins extracted from the chick embryo brain at different developmental stages. The content of hexosamines and uronic acids in the soluble fraction is higher during the whole period examined. The difference between the two fractions reaches a maximum at the 15th day. The insoluble fraction shows the highest content of sialic acid and fucose in comparison with the soluble one, especially toward hatching. The sialic acid/fucose ratio shows a different pattern in the two fractions examined, particularly in the soluble glycoproteins. The patterns of sialic acid and fucose indicate that quantitative and qualitative developmental changes occur in the soluble and insoluble glycoproteins. All sugars examined show significant changes on the 15th day, suggesting that this stage may represent a critical period in the development of the chick embryo brain.

Mutagenic and toxic effects of 4-hydroperoxycyclophosphamide and of 2,4-tetrahydrocyclohexylamine (ASTA-Z-7557) on human lymphocytes cultured in vitro

Certain biological effects exerted by 4-hydroperoxycyclophosphamide and by 2,4-tetrahydrocyclohexylamine (ASTA-Z-7557), utilized in vitro in the therapy of leukemias and lymphomas to eliminate the occult tumor cells in autologous marrow transplantations, were studied in human lymphocytes cultured in vitro. The data show that these drugs exert mutagenic activity eliciting unscheduled DNA synthesis (reparative synthesis) after DNA damage and cause about tenfold higher frequency of sister chromatid exchanges than controls. Furthermore, they exert strong toxic effects, measured as tritiated thymidine uptake inhibition, on mitogen-stimulated dividing cells even if pretreated during the nonproliferative phase of the cell cycle in which the toxic activity of the drugs is not detectable. Data obtained with doses of the drugs similar to those used in the therapy are discussed in terms of the therapeutic use of these chemicals.

Increase of sister chromatid exchange and unscheduled synthesis of deoxyribonucleic acid by acrylonitrile in human lymphocytes in vitro

The investigation has been carried out on cultures grown in the presence of 5 x 10(-1) - 5 x 10(-5) M acrylonitrile with or without a rat liver metabolizing system (S-9 mix). The results obtained showed that acrylonitrile was toxic starting from the 5 x 10(-3) M concentration, caused a significant increase in the sister chromatid exchange (SCE) frequency in comparison with the controls (p less than or equal to 0.001) when the concentration was 5 x 10(-4) M, and elicited reparative deoxyribonucleic acid (DNA) synthesis, determined by tritiated thymidine uptake, particularly when the concentration was 5 x 10(-1) M. These effects were observed in lymphocytes of different donors and after drug activation by the S-9 mix metabolizing system.

[Electrophoretic characterization of glycosaminoglycans during development of the chick embryo skin]

Glycosaminoglycans extracted by CPC precipitation from chick embryo skin at 9, 12, 15, 18, 21 days of incubation were separated by three different electrophoretic methods on acetate cellulose strips. We observed the presence of Hyaluronic acid, Dermatan Sulfate and Chondroitin-4-Sulfate during the whole period considered and of Heparan Sulfate only after the 9th day. Dermatan Sulfate increases until the 15th day then decreases progressively; on the contrary Hyaluronic acid and Chondroitin-4-Sulfate decrease during days 9 to 15 then increase until hatching. Heparan Sulfate appear the 9th day then increases progressively until hatching.

Differential rates of aging in natural populations of old-field mice (Peromyscus polionotus)

Lipofuscin accumulation in cerebellar Purkinje cells was studied in two natural populations of old-field mice (Peromyscus polionotus). Chronological age was estimated by assaying water-insoluble proteins in the eye lens. The number of fluorescent lipofuscin granules per cell was used as an index of physiological age. In both populations, lipofuscin accumulation began at an age of about two months and increased linearly thereafter until the maximum age included in the study (322 days). Sex did not significantly affect the rate of accumulation in either population. The populations did differ in their rates of aging, however. The population with faster rate of lipofuscin accumulation had higher reproductive effort and/or greater adult mortality, and lived in poorer quality habitat. Although genetic influences cannot be discounted, environmental factors were probably responsible for differences in rates of lipofuscin accumulation.

[Further biochemical investigations on glycosaminoglycans extracted from Euglena gracilis]

Polyanionic glycans extracted from Euglena gracilis have been studied by biochemical, chromatographic and electrophoretic analysis. Our results show the presence of a fraction which precipitate with CPC and another one which not precipitate with CPC. The CPC precipitable material fractionated on CPC-Cellulose column shows the presence of 5 Glycosaminoglycans; the not CPC precipitable material contains uronic acid, galactose, sulfate, galactosamine and cannot be related to Keratan sulfate.

[Enzymes of purine metabolism in the nuchal muscle (M. complexus) of chick embryo]

The developmental patterns of enzyme activities related to GMP metabolism have been investigated in chick embryo musculus complexus (m. Complexus). Guanylate phosphatase activity increases conspicuously from 18th to 21st day, guanosine phosphorylase increases on the 21st day and the guanase shows a very low activity during the whole period considered. Xanthine oxidase was always found absent. The results suggest that during the first period of incubation GMP breakdown in chick embryo m. complexus might follow a catabolic pathway, while starting from the 18th day some guanine might be converted to GMP originating a new metabolic pathway as previously suggested for AMP metabolism.

Enzymes involved in adenine nucleotide metabolism of developing chick embryo liver

1. This paper describes the changes in the activity of adenylate deaminase, adenylate and inosinate phosphatase, and adenosine deaminase in the developing chick embryo liver. 2. The adenylate and inosinate phosphatase and adenosine deaminase activity appears considerably higher in chick embryo liver with respect to other chick embryo tissues previously examined. 3. During development the control exerted by ATP on AMP breakdown undergoes variations. Consequently, in the first period of incubation AMP is degraded by the direct pathway (AMP-IMP) and in the last period of incubation by the indirect pathway (AMP-adenosine). In the intermediate period (from the 12th to the 15th day of incubation) both pathways may be followed. 4. The ability to synthesize purine nucleotides through "salvage pathway" seems to be acquired by embryonic liver at least at the 15th day.

Metabolism of glycoproteins in turpentine granuloma

The local synthesis of sialic acid and sialic acid containing glycoproteins in granuloma experimentally produced with turpentine has been investigated by incubating them in vitro with ¹⁴C glucosamine. The content and activity of chromatographically isolated sialic acid of water soluble and water insoluble fractions of tissue incubated at different times after injection of turpentine was determined.

A local synthesis of sialic acid and its incorporation both in the soluble and insoluble fractions were found, with a time depending slope. Chromatography on DEAE Sephadex of glycoproteins obtained from water soluble fraction showed that radioactivity was present in 2 peaks. After papain digestion of the insoluble fraction, the sialic acid containing material could be separated into 2 groups of radioactive glycopeptides on DEAE Sephadex. The data demonstrates that granuloma can synthestize in vitro a considerable variety of glycoproteic materials.