Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AMINES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2001

Structural, computational, and (59)Co NMR studies of primary and secondary amine complexes of Co(III) porphyrins.

Four novel low-spin bis(amine) Co(III) porphyrins [Co(TPP)(BzNH(2))(2)](SbF(6)), 1, [Co(TPP)(1-BuNH(2))(2)](SbF(6)), 2, [Co(TPP)(PhCH(2)CH(2)NH(2))(2)](SbF(6)), 3, and [Co(TPP)(1-MePipz)(2)](SbF(6)), 4, have been synthesized and characterized by low-temperature X-ray crystallography, IR, electronic, and NMR ((1)H, (13)C, and (59)Co) spectroscopy. The mean Co-N(p) distance for the four structures is 1.986(1) A. The Co-N(ax) distances for the 1 degrees amine derivatives average to 1.980(5) A; the axial bonds of the 2 degrees amine derivative are significantly longer, averaging 2.040(1) A. The porphyrin core conformation of 4 is significantly nonplanar (mixture of S(4)-ruf and D(2d)-sad distortions) due to a staggered arrangement of the axial ligands over the porphyrin core and meso-phenyl group orientations < 90 degrees. The X-ray structures have been used with the coordinates for [Co(TPP)(Pip)(2)](NO(3)) (Scheidt et al. J. Am. Chem. Soc. 1973, 95, 8289-8294.) to parametrize a molecular mechanics (MM) force field for bis(amine) complexes of Co(III) porphyrins. The calculations show that two types of crystal packing interactions (van der Waals and hydrogen bonding) largely control the crystallographically observed conformations. Gas phase conformational energy surfaces have been computed for these complexes by dihedral angle driving methods and augmented with population distributions calculated by MD simulations at 298 K; the calculations demonstrate that the bis(1 degrees amine) complexes are significantly more flexible than the bis(2 degrees amine) analogues. (59)Co NMR spectra have been acquired for a range of [Co(TPP)(amine)(2)]Cl derivatives as a function of temperature. The (59)Co chemical shifts increase linearly with increasing temperature due to population of thermally excited vibrational levels of the (1)A(1) ground state. Activation energies for molecular reorientation (tumbling) have been determined from an analysis of the (59)Co NMR line widths as a function of 1/T; lower barriers exist for the conformationally rigid 2 degrees amine derivatives (2.6-3.8 kJ mol(-1)). The (59)Co chemical shifts vary linearly with the DFT-calculated radial expectation values (3d) for the Co(III) ion. The correlation leads to the following order for the sigma-donor strengths of the axial ligands: BzNH(2) > or = Cl(-) > 1-BuNH(2) > PhCH(2)CH(2)NH(2) > 1-Bu(2)NH > Et(2)NH. The (59)Co NMR line widths are proportional to the square of the DFT-calculated valence electric field gradient at the Co nucleus. Importantly, this is the first computational rationalization of the (59)Co NMR spectra of Co(III) porphyrins.

Amines↗
PubMed2005

Revisiting noncovalent So2- amine chemistry: an indicator-displacement assay for colorimetric detection of So2.

A supramolecular approach for potential detection of SO2 is presented, which is based on the "old" donor-acceptor chemistry between SO2 and amines and includes an indicator-displacement assay. When amines were added to Zn-tetraphenylporphyrin 1 in CHCl3, the solution changed from red to dark green. A bathochromic shift of Deltalambda approximately 10 nm was observed for the Soret band, indicating the formation of 1*amine complexes. After this, SO2 gas was introduced, and the original red color of the solution was restored. The Soret band returned to its position for free porphyrin 1. The 1*amine complexes dissociated, and new SO2*amine adducts formed. Porphyrin 1 thus served as an indirect colorimetric indicator for SO2. The system discriminates between SO2 and such typical exhaust gases as COX, NOX, and H2O. From the indicator-displacement assay, the Kassoc values between 1000 and 30 000 M-1 for SO2*amine complexes were determined, which are comparable to those obtained by direct titration experiments between SO2 and the amines. Spectroscopic features of SO2*amine complexes are also presented.

Amines↗
PubMed2006

Influence of lupin (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) germination on microbial population and biogenic amines.

Microbial population and bioactive amine profile and levels of two lupin species (Lupinus luteus L. cv. 4492 and Lupinus angustifolius L. var. zapaton) and fenugreek (Trigonella foenum-graecum L.) seeds as affected by germination were investigated. Microbial population increased considerably mainly in the first stage of germination (2 days), then small changes in bacterial numbers were observed up to 5 days to levels between 7.8 and 8.9 log colony-forming units/g. Microorganisms belonging to the Enterobacteriaceae family were dominant for the legumes tested. Ungerminated legume seeds contained putrescine, cadaverine, histamine, tyramine, spermidine, and spermine. Bioactive amine levels found in fenugreek seeds were between 3- and 4-fold higher than those found in lupin seeds. The highest total amine levels were found in fenugreek seeds [162 mg/kg of dry weight (dw)], followed by L. angustifolius var. zapaton seeds (84 mg/kg of dw) and, finally, L. luteus cv. 4492 (46 mg/kg of dw) seeds. The concentration of individual amines showed a gradual rising trend during the germination period in all tested sprouts, reaching levels >3 times higher than those found in ungerminated seeds. After 5 days of germination, the fenugreek sprouts contained the highest amount of total bioactive amines. Tyramine was the predominant amine in both lupin varieties, whereas cadaverine was the main bioactive amine detected in fenugreek. The results of this work thus indicated that microbial population and biogenic amine levels in the studied lupin and fenugreek sprouts are not a risk for healthy consumers or for individuals with restricted activity of detoxification enzymes.

Biogenic Amines↗
PubMed2006

Catalyst-free chemoselective N-tert-butyloxycarbonylation of amines in water.

[Structure: see text] Catalyst-free N-tert-butyloxycarbonylation of amines in water is reported. The N-t-Boc derivatives were formed chemoselectively without any isocyanate, urea, N,N-di-t-Boc, and O/S-t-Boc as side products. Chiral amines, esters of alpha-amino acids, and beta-amino alcohol afforded optically pure N-t-Boc derivatives. Amino alcohol and 2-aminophenol afforded the N-t-Boc derivative without oxazolidinone formation. Selectivity was observed during competition of aromatic amine vs aliphatic amine, amine vs amino acid ester, amine vs amino alcohol, and primary amine vs secondary amine.

Amines↗
PubMed2002

Correlations of nitrenium ion selectivities with quantitative mutagenicity and carcinogenicity of the corresponding amines.

There is a correlation (r(adj)(2) = 0.5491-0.6338) of quantitative mutagenicity, log m, for a series of heterocyclic (HCAs) and carbocyclic (AAs) aromatic amines in Salmonella typhimurium TA 98 (18 amines) and TA 100 (15 amines) vs log S, the log of the azide/solvent selectivity of the corresponding nitrenium ion. Monocyclic aromatic amines, MAAs, are less mutagenic than other amines of similar log S. Multiple variable linear regression analysis led to a two parameter regression model, significant at the 95% confidence level for both variables, that includes log S and a ring index variable, I(rings), that is 0 for MAAs and 1 for all other amines. These models have r(adj)(2) = 0.8448 for TA 98, and 0.8927 for TA 100. Inclusion of a third variable, Clog P, increases r(adj)(2) to 0.8913 for TA 98 and 0.9011 for TA 100. This model is significant at the 95% confidence level for all variables for TA 98, but only for two of the three variables for TA 100. The confidence level is 80% for Clog P in TA 100. Quantitative carcinogenicity data in mice and rats are more weakly correlated with log S (r(adj)(2) = 0.5357 for 12 amines in mice, r(adj)(2) = 0.4216 for 10 amines in rats). Several two parameter regression models, all containing Clog P and one containing log S, adequately correlate the mouse data.

Amines↗
PubMed2004

Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry.

Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC-MS/MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi(cyclohexylamine)(HMDA) and 4,4'-methylene-(2-chloroaniline)(MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H(2)SO(4) at 100 degrees C for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-)-->[M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine-PFPA derivatives was performed using deuterium labelled amine-PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0-20 ng ml(-1) urine. The instrumental detection limits for the amine-PFPA derivatives were 0.2-3 fmol for MRM of [M - H](-)-->[119](-) and 0.3-8 fmol for [M - H](-)-->[M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC-MS/MS and a reference GC-MS method. No significant difference between the two methods was observed.

Amines↗
PubMed2001

Trace amines: identification of a family of mammalian G protein-coupled receptors.

Tyramine, beta-phenylethylamine, tryptamine, and octopamine are biogenic amines present in trace levels in mammalian nervous systems. Although some "trace amines" have clearly defined roles as neurotransmitters in invertebrates, the extent to which they function as true neurotransmitters in vertebrates has remained speculative. Using a degenerate PCR approach, we have identified 15 G protein-coupled receptors (GPCR) from human and rodent tissues. Together with the orphan receptor PNR, these receptors form a subfamily of rhodopsin GPCRs distinct from, but related to the classical biogenic amine receptors. We have demonstrated that two of these receptors bind and/or are activated by trace amines. The cloning of mammalian GPCRs for trace amines supports a role for trace amines as neurotransmitters in vertebrates. Three of the four human receptors from this family are present in the amygdala, possibly linking trace amine receptors to affective disorders. The identification of this family of receptors should rekindle the investigation of the roles of trace amines in mammalian nervous systems and may potentially lead to the development of novel therapeutics for a variety of indications.

Amino Acid Sequence↗
PubMed2001

Prediction of rodent carcinogenicity of aromatic amines: a quantitative structure-activity relationships model.

The aromatic amines are widely used industrial chemicals and can be found in tobacco smoke as well as in products generated during cooking. In a previous study, we established quantitative structure-activity relationship (QSAR) models linking the carcinogenic potency of non-heterocyclic carcinogenic aromatic amines to a series of molecular determinants. We also found that QSAR models for carcinogenic potency were inadequate in describing the difference between carcinogenic and non-carcinogenic amines [Benigni,R., Giuliani,A., Franke,R. and Gruska,A. (2000) CHEM: Rev., 100, 3697-3714]. In this paper, we derived specific QSAR models for separating active from inactive amines. It appeared that hydrophobicity (as measured by the octanol/water partition coefficient, logP) played a major role in modulating the potency of the carcinogens, whereas mainly electronic (reactivity) and steric characteristics separated the carcinogens from the non-carcinogens. Interestingly, a similar pattern was previously demonstrated by us regarding their mutagenic activity [Benigni,R., Passerini,L., Gallo,G., Giorgi,F. and Cotta-Ramusino,M. (1998) ENVIRON: Mol. Mutagen., 32, 75-83]. Based on the QSAR models found, the molecular determinants of the mechanisms of action of aromatic amines are discussed in detail. The QSAR models obtained can be used directly for estimating the carcinogenicity of other non-heterocyclic aromatic amines for which experimental data are not available. With the QSARs in Benigni et al. (2000) and the present results, a two-step prediction of carcinogenicity of aromatic amines is possible: (i) step 1, yes/no activity from the discriminant functions; and (ii) step 2, if the answer from step 1 is yes then prediction of the degree of potency from the equations in Benigni et al. (2000). Thus, QSAR models can contribute to the following: the direct synthesis of safer chemicals; the estimation of the risk posed by amines present in the environment; setting priorities for further experimentation, thus also reducing the use of experimental animals. Whereas the quality of in vivo experimental data is often questioned, the robustness and interpretability of the present results strongly support the reliability of the rodent carcinogenicity assay.

Amines↗
PubMed2000

Minimization of heterocyclic amines and thermal inactivation of Escherichia coli in fried ground beef.

BACKGROUND: Heterocyclic amine carcinogens are formed during the cooking of a number of foods, especially well-done meats. Lower temperatures and shorter cooking times can minimize the formation of these carcinogens, yet a major food safety concern is that pathogens in the meat must be thermally inactivated. This study investigated cooking techniques that minimize heterocyclic amine formation while simultaneously destroying contaminating bacteria. METHODS: Ground beef patties were inoculated with Escherichia coli K12 bacteria and fried to internal temperatures ranging from 35 degrees C to 70 degrees C in a skillet preheated to 160 degrees C, 180 degrees C, or 200 degrees C. Each patty was then analyzed for four common heterocyclic amines and for surviving bacteria. Additionally, the frequency of turning of the beef patty during cooking was varied (a single turn or multiple turns), length of time required for each patty to reach 70 degrees C was recorded, and heterocyclic amine levels were determined. An additional pan temperature of 250 degrees C was tested for its effect on heterocyclic amine formation but not on bacterial killing. Statistical tests were two-sided. RESULTS: Colony-forming bacteria were reduced by five orders of magnitude at internal temperatures greater than 60 degrees C, regardless of cooking method, and were completely inactivated at 70 degrees C. For patties turned just once, heterocyclic amine levels increased as the cooking temperatures increased. However, levels of heterocyclic amines were statistically significantly lower with turning every minute. For each pan temperature, patties reached 70 degrees C internal temperature sooner when they were turned every minute than when they were turned just once during cooking. CONCLUSION: Lowering the pan temperature and turning the patties frequently can greatly reduce the formation of heterocyclic amines and can simultaneously achieve bacterial inactivation with little or no increase in cooking time, ensuring a product that is safe for human consumption.

Amines↗
PubMed2005

GPCRsclass: a web tool for the classification of amine type of G-protein-coupled receptors.

The receptors of amine subfamily are specifically major drug targets for therapy of nervous disorders and psychiatric diseases. The recognition of novel amine type of receptors and their cognate ligands is of paramount interest for pharmaceutical companies. In the past, Chou and co-workers have shown that different types of amine receptors are correlated with their amino acid composition and are predictable on its basis with considerable accuracy [Elrod and Chou (2002) Protein Eng., 15, 713-715]. This motivated us to develop a better method for the recognition of novel amine receptors and for their further classification. The method was developed on the basis of amino acid composition and dipeptide composition of proteins using support vector machine. The method was trained and tested on 167 proteins of amine subfamily of G-protein-coupled receptors (GPCRs). The method discriminated amine subfamily of GPCRs from globular proteins with Matthew's correlation coefficient of 0.98 and 0.99 using amino acid composition and dipeptide composition, respectively. In classifying different types of amine receptors using amino acid composition and dipeptide composition, the method achieved an accuracy of 89.8 and 96.4%, respectively. The performance of the method was evaluated using 5-fold cross-validation. The dipeptide composition based method predicted 67.6% of protein sequences with an accuracy of 100% with a reliability index > or =5. A web server GPCRsclass has been developed for predicting amine-binding receptors from its amino acid sequence [http://www.imtech.res.in/raghava/gpcrsclass/ and http://bioinformatics.uams.edu/raghava/gpersclass/ (mirror site)].

Artificial Intelligence↗
PubMed2000

Chemical neuroanatomy of the vesicular amine transporters.

Acetylcholine, catecholamines, serotonin, and histamine are classical neurotransmitters. These small molecules also play important roles in the endocrine and immune/inflammatory systems. Serotonin secreted from enterochromaffin cells of the gut epithelium regulates gut motility; histamine secreted from basophils and mast cells is a major regulator of vascular permeability and skin inflammatory responses; epinephrine is a classical hormone released from the adrenal medulla. Each of these molecules is released from neural, endocrine, or immune/inflammatory cells only in response to specific physiological stimuli. Regulated secretion is possible because amines are stored in secretory vesicles and released via a stimulus-dependent exocytotic event. Amine storage-at concentrations orders of magnitude higher than in the cytoplasm-is accomplished in turn by specific secretory vesicle transporters that recognize the amines and move them from the cytosol into the vesicle. Immunohistochemical visualization of specific vesicular amine transporters (VATs) in neuronal, endocrine, and inflammatory cells provides important new information about how amine-handling cell phenotypes arise during development and how vesicular transport is regulated during homeostatic response events. Comparison of the chemical neuroanatomy of VATs and amine biosynthetic enzymes has also revealed cell groups that express vesicular transporters but not enzymes for monoamine synthesis, and vice versa: their function and regulation is a new topic of investigation in mammalian neurobiology. The chemical neuroanatomy of the vesicular amine transporters is reviewed here. These and similar data emerging from the study of the localization of the recently characterized vesicular inhibitory and excitatory amino acid transporters will contribute to understanding chemically coded synaptic circuitry in the brain, and amine-handling neuroendocrine and immune/inflammatory cell regulation.

Acetylcholine↗
PubMed2004

Mammalian central nervous system trace amines. Pharmacologic amphetamines, physiologic neuromodulators.

The presence of the so-called trace amines 2-phenylethylamine, m-tyramine, p-tyramine, m-octopamine, p-octopamine and tryptamine in the mammalian central nervous system has been known for several decades. Despite much initial interest, these amines have largely been thought of as little more than metabolic by-products. The recent description of a family of mammalian trace amine receptors has, however, seen a resurgence of interest in the physiological role of this class of compounds. Although the trace amines are well documented to cause amphetamine-like effects, such responses only occur at concentrations multiple orders of magnitude above normal physiological levels. As such, it seems unlikely that these responses reflect the true physiological role of the trace amines. In this article previous studies showing responses to physiologically relevant concentrations of trace amines are reviewed, along with those showing a reciprocal relationship between trace amine levels and fluctuations in basal monoaminergic tone. On the basis of these studies it is hypothesized that the trace amines function as endogenous neuromodulators of classical monoamine neurotransmitters. These effects are seen as an altered neuronal sensitivity to monoamine neurotransmitters, with no change in neuronal excitability in the absence of neurotransmitter.

Amphetamines↗
PubMed1969

Mechanism of cocaine potentiation of responses to amines.

1. Effects of cocaine on the magnitude of responses to several biologically active amines and on their rates of inactivation were studied in strips of rabbit thoracic aorta in vitro.2. Although cocaine both potentiated responses to noradrenaline, adrenaline and phenylephrine and slowed their inactivation, the correlation between these two parameters under various experimental conditions was poor, and in all cases the delay in intrinsic inactivation was inadequate to account for the observed potentiation.3. Potentiation of responses to noradrenaline by cocaine was little decreased in strips stored at 6 degrees C for up to 10 days, although the response to low doses of tyramine was abolished much earlier. Similarly, cocaine clearly potentiated responses to noradrenaline for at least 28 hr at 37 degrees C, at which time responses to noradrenaline alone were markedly decreased.4. Cocaine potentiated responses to phenylephrine as well after 60 as after 10 min exposure to the amine in strips in which all intra-neuronal disposition of this amine had been eliminated by treatment with reserpine and iproniazid.5. Cocaine effectively potentiated responses to histamine, but had only a slight and variable effect on those to 5-hydroxytryptamine (5-HT). It did not alter the tissue inactivation of histamine, but did significantly slow the inactivation of 5-HT.6. Procaine slowed amine inactivation in the same way and to the same extent as did cocaine, but did not potentiate responses or affect the potentiation produced by cocaine added in its presence.7. Cocaine potentiated responses to methoxamine to approximately the same degree as it did those to noradrenaline, although studies by the oil immersion technique clearly demonstrated that the aortic strips were entirely incapable of inactivating methoxamine.8. The observations reported and discussed are incompatible with the hypothesis that cocaine potentiates responses to sympathomimetic amines because it prevents their inactivation by nerve uptake and storage and thus diverts larger amounts of agonist to tissue receptors. It is concluded that potentiation and inhibition of amine inactivation reflect two largely independent actions of cocaine in this vascular smooth muscle preparation, and probably in other organs, and that potentiation is a generally unreliable criterion of the blockade of processes inactivating sympathomimetic amines or of the importance of these processes in terminating the action of the amines.

Amines↗
PubMed2005

Comparison of ninhydrin method of detecting amine compounds with other methods of halitosis detection.

OBJECTIVES: Halitosis is a result of overactivity of Gram-negative bacteria for which protein amino acids are the major source of energy. Therefore, statistical correlation between concentrations of volatile sulphur compounds (VSCs) and low-molecular-weight amines should be expected. MATERIALS AND METHODS: Eighty-four patients suffering from halitosis and 40 healthy volunteers aged 20-62 years (average 39.7) participated in the study. In all subjects low-molecular-weight amines were evaluated by the ninhydrin method. Patients with halitosis were randomized into treatment groups. Zinc tablets, tablets and mouthwash containing chlorhexidine or lyophilized lactic acid-forming bacteria were used. RESULTS: Analysis showed that the level of amines was highest in subjects with halitosis (0.39, s.d. +/- 0.06, P < 0.001) and correlated significantly with results of VSC measurement and organoleptic scores (P < 0.001). Reduction of amine levels after treatment was statistically significant (P < 0.001). Three months following treatment the amine levels began to increase (0.37, s.d. +/- 0.05). The amine levels in healthy controls were lower (0.29, s.d. +/- 0.07) and remained at a stable level. CONCLUSION: The salivary amine levels significantly correlated with VSC levels and organoleptic scores. Therefore, the ninhydrin method of detecting salivary amines may be an alternative or additional method of diagnosing halitosis. This method may also be used to evaluate treatment efficacy.

Adolescent↗
PubMed1986

Pteridines and mono-amines: relevance to neurological damage.

Patients with phenylalanine hydroxylase deficiency show increased concentrations of biopterins and neopterins, and reduced concentrations of serotonin and catecholamines, when phenylalanine concentrations are raised. The pterin rise reflects increased synthesis of dihydroneopterin and tetrahydrobiopterin, and the amine fall a reduction in amine synthesis due to inhibition by phenylalanine of tyrosine and tryptophan transport into neurones. The pterin and amine changes appear to be independent of each other and are present in the central nervous system as well as the periphery; they disappear when phenylalanine concentrations are reduced to normal. Patients with arginase deficiency show a similar amine disturbance but have normal pterin levels. The amine changes probably contribute neurological symptoms but pterin disturbance is not known to affect brain function. Patients with defective biopterin metabolism exhibit severely impaired amine synthesis due to tetrahydrobiopterin deficiency. Pterin concentrations vary with the site of the defect. Symptoms include profound hypokinesis and other features of basal ganglia disease. Neither symptoms nor amine changes are relieved by controlling phenylalanine concentrations. Patients with dihydropteridine reductase (DHPR) deficiency accumulate dihydrobiopterins and develop secondary folate deficiency which resembles that occurring in patients with defective 5,10-methylene tetrahydrofolate reductase activity. The latter disorder is also associated with Parkinsonism and defective amine and pterin turnover in the central nervous system, and a demyelinating illness occurs in both disorders. In DHPR deficiency cerebral calcification may develop in a similar distribution to that seen in congenital folate malabsorption and methotrexate toxicity. Symptoms are ameliorated by therapy with 5-formyltetrahydrofolate but exacerbated by folic acid.

Amines↗
PubMed2002

Aminated gelatin as a nasal absorption enhancer for peptide drugs: evaluation of absorption enhancing effect and nasal mucosa perturbation in rats.

This study was carried out to evaluate the potential of aminated gelatin as a nasal absorption enhancer for peptide drugs. The absorption-enhancing effect was investigated in rats using insulin and fluorescein isothiocyanate-dextran with a molecular weight of 4.4 kDa (FD-4) as model drugs. The absorption of insulin was estimated by measuring the changes in plasma glucose levels following intranasal administration, and that of FD-4 was determined by measuring its plasma concentration after dosing. The hypoglycaemic effect after intranasal administration of insulin with aminated gelatin significantly increased compared with that after intranasal administration of insulin in phosphate buffered saline, indicating that aminated gelatin effectively enhanced the nasal absorption of insulin. In contrast, neither kind of native gelatin (isoelectric point = 5.0 and 9.0) showed any absorption-enhancing effect. The pH of the formulations and the concentration of aminated gelatin were found to affect the hypoglycaemic effect. In addition, aminated gelatin at a concentration of 0.2% significantly enhanced the absorption and the efflux of FD-4 through the rat nasal mucosa. The possible perturbation of aminated gelatin to nasal mucosa was evaluated by measuring the leaching of lactate dehydrogenase (LDH) using an in-situ perfusion rat model. Aminated gelatin presented a concentration-dependent (0.1-0.4%) but relatively small effect on the LDH leaching from the rat nasal epithelial membrane. These results suggest that positively charged aminated gelatin could be a new absorption enhancer for nasal delivery of peptide drugs.

Absorption↗
PubMed1989

Second-messenger systems underlying amine and peptide actions on cardiac muscle in the horseshoe crab Limulus polyphemus.

The biochemical mechanisms by which octopamine, catecholamines and the peptide proctolin exert their actions on Limulus cardiac muscle were investigated. Amines produced long-lasting increases in the amplitude of contractions evoked by electrical stimulation. At 10(-5) mol l-1, the apparent order of potency for amine-induced increases in evoked contraction amplitude was dopamine approximately equal to octopamine greater than norepinephrine approximately equal to epinephrine. At this dose, amines produced long-lasting increases in the levels of cyclic AMP (octopamine greater than dopamine approximately equal to norepinephrine approximately equal to epinephrine), but not of cyclic GMP, in Limulus cardiac muscle. Like the amines, the adenylate cyclase activator forskolin enhanced cardiac muscle contractility and increased levels of cyclic AMP, but not of cyclic GMP. The phosphodiesterase inhibitor IBMX produced a transient increase in cardiac muscle contractility, but typically produced long-lasting negative inotropy. This agent increased levels of both cyclic AMP and cyclic GMP in Limulus cardiac muscle. Proctolin and the protein kinase C activator phorbol dB increased the contraction amplitude of the intact heart and the electrically stimulated myocardium. These compounds, as well as dopamine, elicited sustained contractures and rhythmic contractions when applied to deganglionated Limulus cardiac muscle rings. Unlike the amines, proctolin and phorbol dB did not increase cardiac muscle cyclic AMP levels. These results suggest that several second-messenger systems may be utilized by amines and peptides to produce excitatory actions on cardiac muscle fibers of the Limulus heart. Cyclic AMP appears to be an important second messenger underlying the effects of amines to enhance cardiac muscle contractility. Pharmacological data suggest that proctolin may alter cardiac muscle contractility and excitability by a mechanism which involves the phosphatidylinositol pathway. Dopamine, unlike the other amines, produces a number of proctolin-like effects and may activate both the cyclic AMP and the phosphatidylinositol systems in Limulus cardiac muscle.

1-Methyl-3-isobutylxanthine↗
PubMed2004

Differences between biogenic amine detection by HPLC methods using OPA and dansyl derivates.

Biogenic amines can be formed and degraded as a result of normal metabolic activity in animals, plants, and microorganisms and are usually produced by the decarboxylation of amino acids. Recent trends in food security are promoting an increasing search for trace compounds that can affect human health. Although they are present in fermented foods and beverages in low quantities, they exhibit interactions with normal human metabolism (e.g., having vasoactive or psychoactive properties) that justify the research on their presence in foods and the possible related toxicological effects that they may cause. Estimation of the biogenic amines histamine, tyramine, agmatine, putrescine, and cadaverine is important not only from the point of view of their toxicity, but also because they can be used as indicators of the degree of freshness or spoilage of food. Until recently, because of the difficulty in detecting and quantifying amines reliably we have had insufficient information about their occurrence in different types of foods and beverages. These problems are related to matrix interference (e.g., the presence of free amino acids) and the low levels at which the amines are found. Early techniques for the determination of biogenic amines in foods were based on thin-layer chromatography. More modern analytical techniques have since been developed that allow the acquisition of reliable quantitative data and better separation/resolution of various amines. The quantitative determination of biogenic amines is generally accomplished by overpressure-layer chromatography, high-performance liquid chromatography (HPLC), and gas chromatography. The use of reverse-phase column and precolumn derivatization was more efficient and faster than the conventional ion-exchange techniques. This study was conducted to evaluate two HPLC derivatization methods for quantitative determination of biogenic amines: the method described by Gonzales de Llano et al. for amino acid analysis and the method described by Eerola et al.

Biogenic Amines↗