‘Pollen potency’: the relationship between atmospheric pollen counts and allergen exposure

Pollen allergies are responsible for a considerable global public health burden, and understanding exposure is critical to addressing the health impacts. Atmospheric pollen counts are routinely used as a predictor of risk; however, immune responses are triggered by specific proteins known as allergens, which occur both within and on the surface of the pollen grain. The ratio between atmospheric pollen counts and allergen concentrations (‘pollen potency’) has been shown to be inconsistent, with potentially important implications for pollen monitoring practice. Despite this, there has been no previous synthesis of the literature and our understanding of the factors that influence pollen potency remains poor. We conducted a scoping review with the aim of deriving a current understanding of: (a) the factors that influence pollen potency; (b) its variation through time, between taxa and by location; and (c) the implications for pollen monitoring practice. Our synthesis found that pollen potency is highly variable within and between seasons, and between locations; however, much of this variability remains unexplained and has not been deeply investigated. We found no predictable pollen potency patterns relating to taxon, geography or time, and inconclusive evidence regarding possible driving factors. With respect to human health, the studies in our synthesis generally reported larger associations between atmospheric allergen loads and allergy symptoms than whole pollen counts. This suggests that pollen potency influences public health risk; however, the evidence base remains limited. Further research is needed to better understand both pollen potency variability and its implications for health.

     

The influence of 1-aminocyclopentane-1-carboxylic acid at position 2 or 3 of AVP and its analogues on their pharmacological properties.

This study describes the synthesis and some pharmacological properties of eight new analogues of arginine vasopressin (AVP) substituted at position 2 or 3 with cycloleucine (1-aminocyclopentane-1-carboxylic acid, Apc). All new peptides were tested for their pressor, antidiuretic and uterotonic in vitro potency. The Apc3 modification resulted in an almost complete loss of potency in all three tests, which is interpreted as a loss of interaction with all three neurohypophyseal hormone receptors. On the other hand, the Apc2 modification resulted in compounds having differently modified activities (high antidiuretic potency, low and graded pressor activity and either no activity or low oxytocin antagonizing activity in the uterotonic in vitro test) thus selectively altering the interaction with the receptors similar to that of 1-aminocyclohexane-1-carboxylic acid (Acc). The results obtained may be helpful for designing new analogues of arginine vasopressin.     

The T lymphocyte response to cytochrome c. V. Determination of the minimal peptide size required for stimulation of T cell clones and assessment of the contribution of each residue beyond this size to antigenic potency

The B10.A T cell proliferative response to pigeon cytochrome c is mainly directed against a single antigenic determinant located at the carboxy-terminal end of the molecule. In the present experiments, we used synthetic peptide analogs of the carboxy-terminal sequence of moth cytochrome c to explore the structural requirements for antigenic potency. The minimum-sized peptide capable of stimulating a full response varied with the T cell clone, but within the limits of the biological systems studied, was shown to be moth fragment 97-103. Addition of more amino acids at the amino terminal end increased the antigenic potency in uneven increments, with a large contribution being made at residue 95. Analysis of amino acid substitutions at this position provided no evidence that it contained a residue that directly contacted the T cell receptor. Instead, good agreement with an analysis that made use of helix-coil transition theory suggested that this residue, as well as others, increased antigenic potency by contributing to the stabilization of the secondary structure of the molecule in an alpha-helical configuration. The maximum effect of chain length on antigenic potency appeared to stop at residue 93, in agreement with the theoretical analysis. However, addition of several more amino-terminal residues to residue 93 showed one additional significant increment of increased potency. This was almost entirely accounted for by a single lysine located four amino acids beyond the glutamic acid at residue 93 (approximately one turn of an alpha-helix away). To experimentally test whether alpha-helix-forming tendencies could account for the increased potency of the larger analogs, the degree of helix formation in trifluoroethanol was assessed by circular dichroism measurements. A good correlation was found between antigenic potency and percentage of alpha-helix for peptides of increasing chain length from moth 95-103 up to moth 86-90; 94-103. These results suggest that secondary structure may play an important role in determining the potency of antigenic determinants involved in the activation of T lymphocytes.     

Variations in Strains of Streptomyces griseus Isolated from a Degenerating Streptomycin-Producing Culture

Streptomycin-resistant strains were isolated from a degenerated streptomycin-producing culture of Streptomyces griseus. From 250 resistant strains, 3 low, 2 intermediate, and 2 high potency strains were selected; these were compared in their morphological, cultural, physiological, and streptomycin-producing properties. Though no definite correlation between streptomycin production and the other properties could be obtained, the following correlations were considered as distinct differences among the low, intermediate, and high potency strains. (i) When streptomycin-producing ability degenerates, more submerged spore formation or fragmentation of mycelium into shorter filaments appears to occur. (ii) On agar medium, low and intermediate potency strains often show finely wrinkled growth; high potency strains do not show such characteristics. (iii) High potency strains excrete a distinct yellow soluble pigment on synthetic agar medium and on glucose-yeast extract agar, but low and intermediate potency strains show little or no ability to form this soluble pigment. (iv) In low and intermediate potency strains, inositol and arginine did not stimulate streptomycin production as they did in high potency strains. Streptamine showed some stimulating effect in the high potency strains and, in contrast, a depressive effect in intermediate potency strains, though streptidine showed a distinctly stimulating effect in all groups of strains employed.     

Sources of variability in foot and mouth disease vaccine potency estimates based on serum neutralizing antibody assay

Some vaccines can be assayed for potency by measuring the serum antibody response they produce in vaccinated test animals. Using data obtained from potency assays on batches of foot and mouth disease vaccine, the sources of variability in such a method were examined. A linear model is proposed for the analysis of replicate serum neutralizing antibody assays, which represents an improvement on the usual approach of working with only a mean serum assay value for each test animal. Components of variance were calculated, allowing the relative importance of the numbers of test animals, or the numbers of serum assays per test animal, to be estimated in terms of the variability of the overall group mean antibody response. A method is described for calculating fiducial intervals for the serological potency estimates, and it is shown that these intervals are no larger than, and are in fact probably smaller than, those obtained from quantal challenge tests. The results have important implications for the design and analysis of similar biological tests used for other products.     

N-Propylnoraporphin-11-O-yl carboxylic esters as potent dopamine D(2) and serotonin 5-HT(1A) receptor dual ligands

A small series of N-propylnoraporphin-11-O-yl carboxylic esters with variant ester lengths were synthesized and their binding potencies at dopamine receptors (D(1), D(2)) and serotonin receptors (5-HT(1A), 5-HT(2A)) were evaluated. Monoesters 3a-f showed binding potency of 100 nM or less for the D(2) receptor, and potency of 10-30 nM for the 5-HT(1A) receptor. Butyryl ester 3d was found to be the best compound possessing the highest potency for both receptors, with K(i) values of 55 and 12 nM for D(2) and 5-HT(1A) receptors, respectively. There is no correlation between the binding potency and the length of the monoesters, but the diesters 9 and 10 were inactive for the D(2) receptor. The dual binding profile of these monoesters for the D(2) and 5-HT(1A) receptors may be useful for the treatment of neuropsychiatric disorders.     

Significant increase of interleukin 6 production in blood mononuclear leukocytes obtained from patients with active inflammatory bowel disease

In the present study, we compared the potency of interleukin 6 production in peripheral blood mononuclear leukocytes between paired patients with active stage and inactive stage of inflammatory bowel disease. Subjects included nine patients with ulcerative colitis, ten patients with Crohn's disease and sex-matched nine healthy volunteers. Mononuclear leukocytes were stimulated with concanavalin A for 24 h to induce interleukin 6 production. Interleukin 6 content in the culture medium was assayed by using specific ELISA and interleukin 6 dependent cell line MH-60. Interleukin 6 production was found to be significantly increased in mononuclear leukocytes from both active ulcerative colitis and Crohn's disease as compared to that from control subjects. There was no significant difference in interleukin 6 production between ulcerative colitis and Crohn's disease. The potency of interleukin 6 production was returned to the control level when the diseases became inactive. The present results, therefore, may indicate some important role of interleukin 6 in the pathogenesis of inflammatory bowel disease and also the potency of interleukin 6 production in mononuclear leukocytes can be an indicator of the activity of inflammatory bowel disease.     

Quantitative assessment of the noncovalent inhibition of sickle hemoglobin gelation by phenyl derivatives and other known agents.

The ability of a variety of phenyl derivatives to inhibit sickle cell hemoglobin gelation was placed on a quantitative scale by parallel equilibrium and kinetic assays. Modifications of the phenyl ring studied include polar, nonpolar, and charged substituents, added aromatic rings, and loss of aromaticity. Other noncovalent inhibitors previously reported to have high potency were measured and placed on the same quantitative scale. Some phenyl derivatives were found to be as effective an any other known noncovalent antigelling agent. The phenyl compounds penetrate easily into red cells, and their potency is tolerant to chemical modification, which holds out the possibility of designing low-toxicity derivatives. On the negative side, the level of potency obtainable appears to be inadequate for clinical use. The best phenyl inhibitors display a functionally defined inhibitory constant (K1) of 75 mM, and it can be estimated that inhibitor concentrations over 20 mM would be necessary to obtain minimal clinically significant benefit. Furthermore, with the variety of modifications tested here, no impressive increase in activity could be achieved over that found in the simplest phenyl compounds.     

Insulin's structural behavior and its relation to activity

This paper discusses the hypothesis that insulin undergoes a conformational change either before or during its binding to the receptor. The evidence for this is not conclusive but allows us to reconcile the following observations: (1) no chemical modification or deletion of invariant surface residues has abolished the hormone's activity—only reduced its potency. (2) Reduction in potency follows many modifications to different side chains, both variant and invariant. (3) There are insulins with perfectly preserved structure (by the criteria of aggregation, spectroscopy, and x-ray analysis) that have markedly reduced potency. (4) Insulins with disturbed structure still exhibit real, sometimes substantial activity.     

Production of Bacillus thuringiensis Berliner var. kurstaki Grown in Alternative Media

Agro - industrial residues and by - products available in southeastern Brazil were used as ingredients for low - cost culture media for liquid fermentation of Bacillus thuringiensis var. kurstaki. Highest spore yield was obtained with a medium containing cheese whey , soya bean milk and molasses (WSM) . Crystals and spores were produced in all media and potency of the final product was highest for nutrient broth + yeast extract medium (NBY) . There was no correlation between the number of spores in the fermented media and the potency of the preparations . Considering all three factors , the potencies , costs and yields of the final products , lowest relative cost was obtained with BMM medium ( Bombyx mori pupae + molasses) . NBY and WSM had intermediate relative cost approximately nine times higher than BMM . The cost analysis suggests that BMM medium should be preferred for local production of B. thuringiensis var . kurstaki in comparison to other media tested . The results also demonstrate the importance of considering yields , cost and potency of the B. thuringiensis preparations in selecting the production medium .     

chi-Conopeptide MrIA partially overlaps desipramine and cocaine binding sites on the human norepinephrine transporter

The interactions of chi-conopeptide MrIA with the human norepinephrine transporter (hNET) were investigated by determining the effects of hNET point mutations on the inhibitory potency of MrIA. The mutants were produced by site-directed mutagenesis and expressed in COS-7 cells. The potency of MrIA was greater for inhibition of uptake by hNET of [3H]norepinephrine (Ki 1.89 microM) than [3H]dopamine (Ki 4.33 microM), and the human dopamine transporter and serotonin transporter were not inhibited by MrIA (to 7 microM). Of 18 mutations where hNET amino acid residues were exchanged with those of the human dopamine transporter, MrIA had increased potency for inhibition of [3H]norepinephrine uptake for three mutations (in predicted extracellular loops 3 and 4 and transmembrane domain (TMD) 8) and decreased potency for one mutation (in TMD6 and intracellular loop (IL) 3). Of the 12 additional mutations in TMDs 2, 4, 5, and 11 and IL1, three mutations (in TMD2 and IL1) had reduced MrIA inhibitory potency. All of the other mutations tested had no influence on MrIA potency. A comparison of the results with previous data for desipramine and cocaine inhibition of norepinephrine uptake by the mutant hNETs reveals that MrIA binding to hNET occurs at a site that is distinct from but overlaps with the binding sites for tricyclic antidepressants and cocaine.     

改良抗体结合实验检测灭活狂犬病疫苗效价

目的:建立抗体结合试验检测狂犬病疫苗(aG株)效价的方法。方法:将待检测疫苗与疫苗标准品梯度稀释后分别加入人抗狂犬病毒免疫球蛋白国家标准品中和1 h,之后加入80%感染剂量的狂犬病毒CVS-11,体外中和1h后接种BSR细胞,培养24 h后免疫荧光染色,在显微镜下观察结果,通过检测剩余病毒量计算待检疫苗的效价,同时与小鼠中和试验法(NIH法)测定狂犬病疫苗效价进行比较。结果:2种方法对8个样品效价的检测结果无显著统计学差异(P=0.997,配对t检验)。结论:初步建立了改良抗体结合试验,可用于狂犬病疫苗中间产品的质量控制。     

Analogs of MTII, lactam derivatives of alpha-melanotropin, modified at the N-terminus, and their selectivity at human melanocortin receptors 3, 4, and 5.

In search for selective agonists at human melanocortin-4 receptor, proline-substituted analogs of MTII, a potent nonselective agonist at melanocortin receptors, were prepared by solid-phase syntheses and evaluated for their ability to bind and activate human MC-3, MC-4, and MC-5 receptors. Replacement of Nle(4) with Pro resulted in [Pro(4)]MTII with affinity to and agonist potency at hMC-4R similar to MTII, but with about 400-fold lower potency at hMC-5R and about 20-fold lower potency at hMC-3R. The substantial increase in selectivity of [Pro(4)]MTII with respect to hMC-5R prompted us to investigate additional analogs of MTII with modified N-termini. The Ac-Nle(4) segment, not encompassed in the lactam ring, was substituted with flexible, hydrophobic, or hydrophilic substituents, and also, with residues resembling proline. The similar agonist potency of these peptides to that of MTII at hMC-4R but significantly lower activity of these compounds at hMC-5R demonstrated that the N-terminal fragment of MTII has virtually no effect on the binding affinity and activation at hMC-4R, but it is essential for full potency at hMC-5R.     

Structure-function analysis of amino acid 74 of human RAMP1 and RAMP3 and its role in peptide interactions with adrenomedullin and calcitonin gene-related peptide receptors

The receptors for calcitonin gene-related peptide (CGRP) and adrenomedullin (AM) are complexes of the calcitonin receptor-like receptor (CLR) and receptor activity-modifying proteins (RAMP). The CGRP receptor is a CLR/RAMP1 pairing whereas CLR/RAMP2 and CLR/RAMP3 constitute two subtypes of AM receptor: AM₁ and AM₂, respectively. Previous studies identified Glu74 in RAMP3 to be important for AM binding and potency. To further understand the importance of this residue and its equivalent in RAMP1 (Trp74) we substituted the native amino acids with several others. In RAMP3, these were Trp, Phe, Tyr, Ala, Ser, Thr, Arg and Asn; in RAMP1, Glu, Phe, Tyr, Ala and Asn substitutions were made. The mutant RAMPs were co-expressed with CLR in Cos7 cells; receptor function in response to AM, AM₂/intermedin and CGRP was measured in a cAMP assay and cell surface expression was determined by ELISA. Phe reduced AM potency in RAMP3 but had no effect in RAMP1. In contrast, Tyr had no effect in RAMP3 but enhanced AM potency in RAMP1. Most other substitutions had a small effect on AM potency in both receptors whereas there was little impact on CGRP or AM₂ potency. Overall, these data suggest that the geometry and charge of the residue at position 74 contribute to how AM interacts with the AM₂ and CGRP receptors and confirms the role of this position in dictating differential AM pharmacology at the AM₂ and CGRP receptors.     

Discovery of DS-6930, a potent selective PPARγ modulator. Part II: Lead optimization

Attempts were made to reduce the lipophilicity of previously synthesized compound (II) for the avoidance of hepatotoxicity. The replacement of the left-hand side benzene with 2-pyridine resulted in the substantial loss of potency. Because poor membrane permeability was responsible for poor potency in vitro, the adjustment of lipophilicity was examined, which resulted in the discovery of dimethyl pyridine derivative (I, DS-6930). In preclinical studies, DS-6930 demonstrated high PPARγ agonist potency with robust plasma glucose reduction. DS-6930 maintained diminished PPARγ-related adverse effects upon toxicological evaluation in vivo, and demonstrated no hepatotoxicity. Cofactor recruitment assay showed that several cofactors, such as RIP140 and PGC1, were significantly recruited, whereas several canonical factors was not affected. This selective cofactor recruitment was caused due to the distinct binding mode of DS-6930. The calcium salt, DS-6930b, which is expected to be an effective inducer of insulin sensitization without edema, could be evaluated clinically in T2DM patients.     

Metabolism and biological potency of 5,6-monoepoxy-β-carotene and 5,6:5′,6′-diepoxy-β-carotene

1. 5,6-Monoepoxy-beta-carotene and 5,6:5',6'-diepoxy-beta-carotene were partially converted into the furanoid forms during passage through the rat stomach. 2. The monoepoxide was converted into vitamin A in the small intestine and showed a biological potency 21% of that of beta-carotene. Neither beta-carotene nor 5,6-monoepoxyvitamin A was formed. 3. Intraperitoneal administration of the monoepoxide led to the accumulation of the unchanged compound in the liver and other tissues. 4. The diepoxide gave no beta-carotene or vitamin A or 5,6-monoepoxyvitamin A when given orally and showed no biological potency. 5. The significance of these results with special reference to the mechanism of formation of vitamin A from beta-carotene is discussed.     

Influence of dose and route of administration of bovine follicular fluid and the suppressive effect of purified bovine inhibin (Mr 31,000) on plasma FSH concentrations in ovariectomized ewes

Ovariectomized Merino ewes were used to develop an in-vivo bioassay for purified bovine inhibin of Mr 31,000. Various doses (0.25, 0.5, 1 or 2 ml) of bovine follicular fluid, given either by the intravenous (i.v.) or intracarotid route (i.c.) resulted in significant linear dose-related suppression of plasma FSH and interval to maximum suppression. Control ewes (1.0 ml steer plasma) showed no significant change in FSH over the same period. Doses of 470 and 2590 U of pure inhibin given i.v. caused a significant suppression of FSH in plasma in all ewes. The in-vivo potency estimate of the high dose (2760 U, 1420-4690 fiducial limits) agreed well with the in-vitro assay of potency. There were no significant changes observed in mean plasma LH after treatment with the higher dose of pure inhibin. There were no rebound effects of treatment with bovine follicular fluid or pure inhibin on FSH concentrations above that of controls. It is concluded that the form of bovine inhibin of Mr 31,000, which is believed to be the predominant circulating form, is biologically active when administered in vivo.