The prediction of human oral absorption for diffusion rate-limited drugs based on heuristic method and support vector machine

Support vector machine (SVM), as a novel machine learning technique, was used for the prediction of the human oral absorption for a large and diverse data set using the five descriptors calculated from the molecular structure alone. The molecular descriptors were selected by heuristic method (HM) implemented in CODESSA. At the same time, in order to show the influence of different molecular descriptors on absorption and to well understand the absorption mechanism, HM was used to build several multivariable linear models using different numbers of molecular descriptors. Both the linear and non-linear model can give satisfactory prediction results: the square of correlation coefficient R(2) was 0.78 and 0.86 for the training set, and 0.70 and 0.73 for the test set respectively. In addition, this paper provides a new and effective method for predicting the absorption of the drugs from their structures and gives some insight into structural features related to the absorption of the drugs.

Quantitative Prediction of logk of Peptides in High-Performance Liquid Chromatography Based on Molecular Descriptors by Using the Heuristic Method and Support Vector Machine

A new method support vector machine (SVM) and the heuristic method (HM) were used to develop the nonlinear and linear models between the capacity factor (logk) and seven molecular descriptors of 75 peptides for the first time. The molecular descriptors representing the structural features of the compounds only included the constitutional and topological descriptors, which can be obtained easily without optimizing the structure of the molecule. The seven molecular descriptors selected by the heuristic method in CODESSA were used as inputs for SVM. The results obtained by SVM were compared with those obtained by the heuristic method. The prediction result of the SVM model is better than that of heuristic method. For the test set, a predictive correlation coefficient R = 0.9801 and root-mean-square error of 0.1523 were obtained. The prediction results are in very good agreement with the experimental values. But the linear model of the heuristic method is easier to understand and ready to use for a chemist. This paper provided a new and effective method for predicting the chromatography retention of peptides and some insight into the structural features which are related to the capacity factor of peptides.

QSAR Models for the Prediction of Binding Affinities to Human Serum Albumin Using the Heuristic Method and a Support Vector Machine

The binding affinities to human serum albumin for 94 diverse drugs and drug-like compounds were modeled with the descriptors calculated from the molecular structure alone using a quantitative structure-activity relationship (QSAR) technique. The heuristic method (HM) and support vector machine (SVM) were utilized to construct the linear and nonlinear prediction models, leading to a good correlation coefficient (R2) of 0.86 and 0.94 and root-mean-square errors (rms) of 0.212 and 0.134 albumin drug binding affinity units, respectively. Furthermore, the models were evaluated by a 10 compound external test set, yielding R2 of 0.71 and 0.89 and rms error of 0.430 and 0.222. The specific information described by the heuristic linear model could give some insights into the factors that are likely to govern the binding affinity of the compounds and be used as an aid to the drug design process; however, the prediction results of the nonlinear SVM model seem to be better than that of the HM.

Novel Strategies in Cancer Therapeutics: Targeting Enzymes Involved in Cell Cycle Regulation and Cellular Proliferation

Tumor development, growth, and progression depend on some combination of altered cell cycle regulation, excessive growth factor pathway activation, and decreased apoptosis. Understanding the complex molecular mechanisms that underlie these processes should therefore lead to the identification of potential targets for therapeutic intervention. The estrogen receptor and HER-2/neu were among the earliest targets investigated, ultimately leading to the widespread use of tamoxifen and trastuzumab, respectively, in the treatment of breast cancer. Major research advances have since led to other classes of targeted therapies, including cyclin-dependent kinase inhibitors, histone deactylase inhibitors, and receptor tyrosine kinase inhibitors. The following review provides a discussion of the molecular biology associated with each of these types of therapies as well as a detailed summary of the preclinical and clinical data published on selected compounds from each of these subgroups.

Study of the Quantitative Structure-Mobility Relationship of Carboxylic Acids in Capillary Electrophoresis Based on Support Vector Machines

The support vector machines (SVM), as a novel type of learning machine, were used to develop a quantitative structure-mobility relationship (QSMR) model of 58 aliphatic and aromatic carboxylic acids based on molecular descriptors calculated from the structure alone. Multiple linear regression (MLR) and radial basis function neural networks (RBFNNs) were also utilized to construct the linear and the nonlinear model to compare with the results obtained by SVM. The root-mean-square errors in absolute mobility predictions for the whole data set given by MLR, RBFNNs, and SVM were 1.530, 1.373, and 0.888 mobility units (10(-5) cm(2) S(-1) V(-1)), respectively, which indicated that the prediction result agrees well with the experimental values of these compounds and also revealed the superiority of SVM over MLR and RBFNNs models for the prediction of the absolute mobility of carboxylic acids. Moreover, the models we proposed could also provide some insight into what structural features are related to the absolute mobility of aliphatic and aromatic carboxylic acids.

An Accurate QSPR Study of O−H Bond Dissociation Energy in Substituted Phenols Based on Support Vector Machines

The support vector machine (SVM), as a novel type of learning machine, was used to develop a Quantitative Structure-Property Relationship (QSPR) model of the O-H bond dissociation energy (BDE) of 78 substituted phenols. The six descriptors calculated solely from the molecular structures of compounds selected by forward stepwise regression were used as inputs for the SVM model. The root-mean-square (rms) errors in BDE predictions for the training, test, and overall data sets were 3.808, 3.320, and 3.713 BDE units (kJ mol(-1)), respectively. The results obtained by Gaussian-kernel SVM were much better than those obtained by multiple linear regression, radial basis function neural networks, linear-kernel SVM, and other QSPR approaches.

Prediction of the Isoelectric Point of an Amino Acid Based on GA-PLS and SVMs

The support vector machine (SVM), as a novel type of a learning machine, for the first time, was used to develop a QSPR model that relates the structures of 35 amino acids to their isoelectric point. Molecular descriptors calculated from the structure alone were used to represent molecular structures. The seven descriptors selected using GA-PLS, which is a sophisticated hybrid approach that combines GA as a powerful optimization method with PLS as a robust statistical method for variable selection, were used as inputs of RBFNNs and SVM to predict the isoelectric point of an amino acid. The optimal QSPR model developed was based on support vector machines, which showed the following results: the root-mean-square error of 0.2383 and the prediction correlation coefficient R=0.9702 were obtained for the whole data set. Satisfactory results indicated that the GA-PLS approach is a very effective method for variable selection, and the support vector machine is a very promising tool for the nonlinear approximation.

In vitro antiviral activities of Caesalpinia pulcherrima and its related flavonoids

The aim of this study was to search for new antiviral agents from Chinese herbal medicine. Pure flavonoids and aqueous extracts of Caesalpinia pulcherrima Swartz were used in experiments to test their influence on a series of viruses, namely herpesviruses (HSV-1, HSV-2) and adenoviruses (ADV-3, ADV-8, ADV-11). The EC50 was defined as the concentration required to achieve 50% protection against virus-induced cytopathic effects, and the selectivity index (SI) was determined as the ratio of CC50 (concentration of 50% cellular cytotoxicity) to EC50. Results showed that aqueous extracts of C. pulcherrima and its related quercetin possessed a broad-spectrum antiviral activity. Among them, the strongest activities against ADV-8 were fruit and seed (EC50 = 41.2 mg/l, SI = 83.2), stem and leaf (EC50 = 61.8 mg/l, SI = 52.1) and flower (EC50 = 177.9 mg/l, SI = 15.5), whereas quercetin possessed the strongest anti-ADV-3 activity (EC50 = 24.3 mg/l, SI = 20.4). In conclusion, some compounds of C. pulcherrima which possess antiviral activities may be derived from the flavonoid of quercetin. The mode of action of quercetin against HSV-1 and ADV-3 was found to be at the early stage of multiplication and with SI values greater than 20, suggesting the potential use of this compound for treatment of the infection caused by these two viruses.

QSAR study of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl) pyrimidine-5-carboxylate: an inhibitor of AP-1 and NF-kappa B mediated gene expression based on support vector machines

The support vector machine, as a novel type of learning machine, for the first time, was used to develop a QSAR model of 57 analogues of ethyl 2-[(3-methyl-2,5-dioxo(3-pyrrolinyl))amino]-4-(trifluoromethyl)pyrimidine-5-carboxylate (EPC), an inhibitor of AP-1 and NF-kappa B mediated gene expression, based on calculated quantum chemical parameters. The quantum chemical parameters involved in the model are Kier and Hall index (order3) (KHI3), Information content (order 0) (IC0), YZ Shadow (YZS) and Max partial charge for an N atom (MaxPCN), Min partial charge for an N atom (MinPCN). The mean relative error of the training set, the validation set, and the testing set is 1.35%, 1.52%, and 2.23%, respectively, and the maximum relative error is less than 5.00%.

Diagnosing breast cancer based on support vector machines

The Support Vector Machine (SVM) classification algorithm, recently developed from the machine learning community, was used to diagnose breast cancer. At the same time, the SVM was compared to several machine learning techniques currently used in this field. The classification task involves predicting the state of diseases, using data obtained from the UCI machine learning repository. SVM outperformed k-means cluster and two artificial neural networks on the whole. It can be concluded that nine samples could be mislabeled from the comparison of several machine learning techniques.

Solid-phase microextraction from small volumes of sample in a glass capillary

A new sampling method is proposed for solid-phase microextraction (SPME), in which the extraction is carried out in a glass capillary containing a few microliters of sample. When an adsorption-type fiber is used for SPME, the equilibrium between aqueous sample and coating can be described by a Langmuir isotherm. Since the total amount of analytes and coexisting substances stays at a low level in a small volume of sample, the linear concentration range of analytes will be extended for SPME to be applied in quantification and the interference caused by sample matrix will be reduced. In addition, sampling in a capillary has a short diffusion distance and extraction equilibrium is established in 5-10 min. It is important in clinical analysis and therapeutic drug monitoring to be able to analyse sample volumes of samples. The feasibility of the new sampling method is demonstrated by the extractions of p-hydroxybenzaldehyde and a synthetic solution containing 1-naphthol, paeonol and 1-naphthylamine.

Quantitative prediction of liquid chromatography retention of N-benzylideneanilines based on quantum chemical parameters and radial basis function neural network

Based on quantum chemical parameters and a simple numerical coding, the liquid chromatography retention of bifunctionally substituted N-benzylideneaniles (NBA) has been predicted using a radial basis function neural network (RBFNN) model. The quantum chemical parameters involved in the model are dipole moment (m), energies of the highest occupied and lowest unoccupied molecular orbitals (E(homo,) E(lumo)), net charge of the most negative atom (Q(min)), sum of absolute values of the charges of all atoms in two given functional groups (Delta), total energy of the molecule (E(T)), weight of the molecule (W), and numerical coding (N). N was used to indicate the different positions of two substituents. The predictive values are consistent with the experimental results. The mean relative error of the testing set is 1.6%, and the maximum relative error is less than 5.0%. In this work the success of the whole modeling process only depends on the optimization of the spread parameter in network.

Toxicity of different industrial effluents in Taiwan: a comparison of the sensitivity of Daphnia similis and Microtox

Industrial effluents are known to exhibit toxicity toward different aquatic organisms. In Taiwan management of these discharges still relies on chemical and physical and physical characteristics of water, although various standard method for assessing aquatic toxicity have been proposed by the Taiwan Environmental Protection Administration. In this study we examined the toxicity and compared the sensitivity of different types of industrial effluents using two proposed toxicity tests: the Daphnia similis acute toxicity test and the Microtox acute assay (Vibrio fischeri). Results showed that electroplating effluents were the most toxic of all the effluents tested, followed by acrylonitrile manufacturing, pulp/paper, and tannery effluents. The EC50 of an electroplating effluent for D. similis and V. fischeri (15 min) was as low as, respectively, 2.9% and 3.9% of the whole effluent. The other effluents were not acutely toxic to either organism tested. However, the tests exhibited different sensitivity toward various discharges. Only the electroplating and acrylonitrile manufacturing effluents had effects on both organisms. These results indicate the importance of the incorporation of aquatic toxicity tests into the management scheme for treated wastewaters.

Synthesis of halogen-substituted 3-deazaadenosine and 3-deazaguanosine analogues as potential antitumor/antiviral agents

Various 2-halogen-substituted analogues (38, 39, 43 and 44), 3-halogen-substituted analogues (51 and 52), and 2',3'-dihalogen-substituted analogues (57-60) of 3-deazaadenosine and 3-halogen-substituted analogues (61 and 62) of 3-deazaguanosine have been synthesized as potential anticancer and/or antiviral agents. Among these compounds, 3-deaza-3-bromoguanosine (62) showed significant cytotoxicity against L1210, P388, CCRF-CEM and B16F10 cell lines in vitro, producing IC50 values of 3, 7, 9 and 7 microM, respectively. Several 3-deazaadenosine analogues (38, 51, 57 and 59) showed moderate to weak activity against hepatitis B virus.

Effects and mechanisms of aloe-emodin on cell death in human lung squamous cell carcinoma

Aloe-emodin (1,8-dihydroxy-3-(hydroxymethyl)-anthraquinone) is an active component from the root and rhizome of Rheum palmatum. The study investigated the effects and mechanisms of aloe-emodin-induced cell death in human lung squamous cell carcinoma cell line CH27. Aloe-emodin (40 microM)-induced CH27 cell apoptosis was confirmed by DNA fragmentation (DNA ladders and sub-G(1) formation). Aloe-emodin-induced apoptosis of CH27 cells involved modulation of the expression of Bcl-2 family proteins, such as BclX(L), Bag-1, and Bak, and was associated with the translocation of Bak and Bax from cytosolic to particulate fractions. Aloe-emodin-treated CH27 cells had an increased relative abundance of cytochrome c in the cytosolic fraction. Results demonstrated that the activation of caspase-3, caspase-8, and caspase-9 is an important determinant of apoptotic death induced by aloe-emodin. These results suggest that aloe-emodin induces CH27 cell death by the Bax and Fas death pathway.

Microsomal monooxygenase activity in Tilapia (Oreochromis mossambicus) exposed to a bleached kraft mill effluent using different exposure systems

Bleached kraft pulp and paper mill effluents (BKMEs) are known to have adverse effects on aquatic organisms. One of the effects of BKMEs is its ability to induce cytochrome P4501A activity in exposed fish. 7-Ethoxyresorufin O-deethylase (EROD) activity is the most common biomarker used to measure the mixed-function monooxygenase activity. In this study, Tilapia were exposed to BKMEs using different exposure systems and their hepatic EROD activity, as well as liver/somatic index (LSI), were determined. In the Phase I study, Tilapia treated with betaNF and a whole (100%) BKME using a static, non-renewal system exhibited statistically significant EROD induction, but LSI values were not altered. In the Phase II study, fish were either caged in the mill's fishpond with the whole effluent passing through or cultured in tanks receiving 100% of the BKME continuously using a flow-through system in the laboratory. Their EROD activities were then compared with the non-exposed fish (control). The EROD activities in both groups of fish were elevated significantly with the greatest induction being observed in the field-exposed group. The LSI values in all of the field-exposed fish were significantly greater than the control Tilapia. The EROD assay was sensitive in detecting biological changes in fish exposed to the BKME. Further studies are warranted to better understand the impacts of BKMEs on aquatic organisms in Taiwan.

Results on single cell PCR for Huntington's gene and WAVE product analysis for preimplantation genetic diagnosis

Triple repeat base pair amplification is the basis for a number of prevalent genetic diseases such as Huntington's, Fragile X, Myotonic Dystrophy and others. We have chosen to investigate the use of PCR to amplify a portion of the Huntington's gene in single cells in order to develop a clinical test system for preimplantation genetic diagnosis (PGD). Amplification of CAG triple repeat sequences poses difficulties due to resistance of GC melting for amplification. Special PCR modifications are necessary to carry out the amplification of GC rich areas found in most triple base pair expansions. We have used a modified polymerase chain reaction (PCR) protocol to amplify the expanded repeat sequence of the Huntington's gene with satisfactory efficiency. Detection of the amplified expanded CAG repeats is shown to be possible using both agarose gel electrophoresis and high definition denaturing high pressure liquid (DHPLC) chromatography. The incidence of allele dropout (ADO) is documented.

Identification of a novel cytokine, ML-1, and its expression in subjects with asthma

A novel gene, designated ML-1, was identified from a human genomic DNA clone and human T cell cDNA sequences. The second exon of ML-1 gene shares significant sequence identity with the gene encoding IL-17 (IL-17). ML-1 gene expression was up-regulated in activated PBMCs, CD4(+) T cells, allergen-specific Th0, Th1, and Th2 clones, activated basophils, and mast cells. Increased expression of the ML-1 gene, but not IL-17, was seen following allergen challenge in four asthmatic subjects, suggesting its role in allergic inflammatory responses. ML-1 from transiently transfected COS-7 cells was able to induce gene expression and protein production for IL-6 and IL-8 (at 10 ng/ml of ML-1: for IL-6, 599.6 +/- 19.1 pg/ml; for IL-8, 1724.2 +/- 132.9 pg/ml; and at 100 ng/ml of ML-1: for IL-6, 1005.3 +/- 55.6 pg/ml; for IL-8, 4371.4 +/- 280.5 pg/ml; p < 0.05 for both doses vs baseline) in primary bronchial epithelial (PBE) cells. Furthermore, increased expression of ICAM-1 was found in ML-1-stimulated PBE cells (mean fluorescence intensity (MFI) = 31.42 +/- 4.39 vs baseline, MFI = 12.26 +/- 1.77, p < 0.05), a functional feature distinct from IL-17 (MFI = 11.07 +/- 1.22). This effect was not inhibited by a saturating amount of IL-17. These findings demonstrate that ML-1 is a novel cytokine with a distinct function, and suggest a different receptor for ML-1 on PBE cells.

The effects of an inhaled beta(2)-adrenergic agonist on lower esophageal function: a dose-response study

STUDY OBJECTIVES

Albuterol, a beta(2)-adrenergic agonist that is commonly used to treat asthma, reduces bronchial smooth muscle tone. The pharmacodynamics of inhaled albuterol on esophageal function were studied in healthy volunteers.

DESIGN

A prospective, randomized, placebo-controlled, double-blind crossover design.

SETTING

An academic medical center.

PATIENTS

Nine healthy volunteers (five men, four women; age, 22 to 30 years).

INTERVENTIONS

Albuterol (2.5 to 10 mg) or placebo was given via nebulizer. Volunteers were studied at two sessions, 1 week apart, using a 6-cm manometry assembly and a low-compliance pneumohydraulic pump. The percentage of lower esophageal sphincter (LES) relaxation, the frequency of transient LES relaxations (TLESRs), and the amplitude, duration, and propagation velocity of esophageal contractions were measured at 5 and 10 cm above the LES. Dependent measures were evaluated using two-way, repeated-measures analysis of variance.

MEASUREMENTS AND RESULTS

Albuterol therapy reduced LES basal tone in a dose-dependent manner (baseline, 17.0 +/- 2.6 mm Hg; at 10 mg, 8.9 +/- 2.1 mm Hg; p = 0.01). The frequency of TLESRs was not different from placebo (not significant). Albuterol reduced the amplitude of esophageal contractions at 5 cm above the LES (baseline, 72.5 +/- 18.6 mm Hg; at 10 mg, 48.8 +/- 10.0 mm Hg; p<0.05). A significant reduction in esophageal body contractile amplitudes was noted at 10 cm (F[1,6] = 7.05; p<0.05).

CONCLUSIONS

Inhaled albuterol reduced LES basal tone and contractile amplitudes in the smooth muscle esophageal body in a dose-dependent manner. Inhaled beta(2)-agonists may increase the likelihood of acid reflux in a subset of patients who receive cumulative dosing.

Repetitive ozone exposure of young adults: evidence of persistent small airway dysfunction

Earlier, we found that acute ozone (O3) exposure caused, along with inflammation, greater, more protracted changes in small airway function (isovolumetric V max at intermediate to low lung volumes) than in FVC or FEV1. To test if this distinction prevailed with repetitive O3 exposure, we exposed eight healthy adults on four consecutive days alternatively to filtered air (FA) and O3 (0.25 ppm x 2 h). Isovolumetric FEF25-75, Vmax50, and Vmax75, were grouped into a single value representing small airway function (SAW(grp)); respiratory frequency (f) and tidal volume (VT) were monitored during exercise. On Day 5, peripheral airway resistance (Rp) was measured followed by lavage. All daily spirometric and ventilatory changes declined in magnitude (adapted) after one or more days of O3 exposure. In addition, SAW(grp), f, and VT showed persistent changes beginning with Day 2, denoted either by depression of the preexposure baseline (SAW(grp)) or exaggerated tachypnea during exercise. O3-induced neutrophilia (p = 0.04) was present in lavage fluid. The possible relationship between these persistent changes in small airway function, measured in days, and the likelihood of cumulative injury in the same region if exposure is long term, is unknown.

Erythrocytic glutathione and plasma cysteine status of human immunodeficient patients

Both deficient and normal blood levels of glutathione (GSH) and cysteine (Cys) have been reported in HIV patients, a discrepancy that has been attributed to different methodologies. The goal of this study was to apply our analytical method to this problem. Blood samples from HIV patients and healthy subjects were collected, immediately stabilized, and quantified using high performance liquid chromatography with dual electrochemical detection. The results showed that the erythrocytic GSH levels were the same in healthy subjects and in HIV patients regardless of their CD4 lymphocyte level. Only those with the lowest CD4 level plus opportunistic infections had supranormal [corrected] GSH concentrations (P < 0.001). GSH plus glutathione disulfide (GSSG) levels also were normal in patients. However, the Cys contents were higher in patients than in controls (P < 0.05). These findings demonstrated that HIV patients have normal erythrocytic GSH concentrations and supranormal Cys levels.

Synthesis and biological evaluation of L- and D-configurations of 2',3'-dideoxy-4'-C-methyl-3'-oxacytidine analogues

Novel L- and D-configuration 2',3'-dideoxy-4'-C-methyl-3'-oxacytidine and their 5-fluoro analogues have been synthesized from 1-benzyloxy-2-propanone and L-ascorbic acid in eight steps and evaluated for biological activity.

Primary squamous cell carcinoma of the thyroid gland: an entity with aggressive clinical behaviour and distinctive cytokeratin expression profiles

AIMS

Primary squamous cell carcinoma of the thyroid gland is uncommon. This study aims to identify the clinicopathological features and the pattern of expression of cytokeratins and oncoproteins in this tumour.

METHODS AND RESULTS

Histological slides from Chinese patients with thyroid cancer treated in our institution from 1980 to 1999 were reviewed. Patients with primary squamous cell carcinoma of the thyroid were identified and their clinical records were analysed. The expression of cytokeratins (CKs), p53 and p21 in these cases were also studied by an immunohistochemical method. Four women (mean age 71 years) with squamous cell carcinoma of thyroid were found. The main presenting features were signs and symptoms of airway obstruction in three patients and neck swelling in one. The tumours were located at the right lobe (n=2), left lobe (n=1) or in both lobes of the thyroid (n=1). One patient died shortly after admission and the other three died within 4 months after thyroidectomy. The p53 protein was positive in 50% (2/4) of the tumours and p53+ tumours were poorly differentiated. The tumours were negative for p21. CK19 was expressed in all the tumours while CK7 expression was noted in 3/4 of the tumours. One carcinoma showed focal positivity to CK18. The tumours were negative for CKs 1, 4, 6, 10/13 and 20. The pattern of cytokeratin expression in squamous cell carcinoma of the thyroid gland was different from carcinoma showing thymus-like differentiation (CASTLE) of the thyroid gland and oesophageal squamous cell carcinoma.

CONCLUSIONS

Squamous cell carcinoma of the thyroid has aggressive clinical behaviour and characteristic CK expression pattern. p53 over-expression in these tumours was associated with tumour differentiation.

Sulfation of flavonoids and other phenolic dietary compounds by the human cytosolic sulfotransferases

The protective effects of diet, especially soya products, tea, and many fruits, against a variety of human cancers, as suggested by epidemiological studies, has focused attention on flavonoids, isoflavonoids, and other phenolic dietary compounds as chemoprotectants. Among the mechanisms suggested for their chemoprotective action, their ability to inhibit the bioactivation of carcinogens by the human cytosolic sulfotransferases (STs) and the direct effects of their sulfoconjugates are being increasingly studied. We report here a systematic study on the sulfation of representative flavonoids, isoflavonoids, anti-oxidants, and other phenolic dietary compounds by all ten known human cytosolic STs. All ten recombinant human cytosolic STs were prepared in a pure form and tested for their sulfating activities with a variety of these compounds. P-form (SULT1A1) phenol ST (PST) showed high sulfating activity with most of these compounds. M-form (SULT1A3) PST showed high activity with the flavonoids but not with the isoflavonoids. SULT1C ST #2 showed high activity with the isoflavonoids and also sulfated most of the other compounds. Possible relevance of these results to the chemoprotective effects of these dietary compounds is discussed.

Effects of prednisone on the cellular responses and release of cytokines and mediators after segmental allergen challenge of asthmatic subjects

BACKGROUND

Systemic glucocorticoids are a major therapy for the management of allergic inflammation and asthma; however, information about their effects in vivo are limited.

OBJECTIVE

This study was performed to examine the effects of prednisone on inflammatory mediators, cytokines, and cellular responses in the model of segmental allergen challenge (SAC) of allergic asthmatic subjects.

METHODS

The effects of a 3-day pretreatment with oral prednisone (30 mg twice daily) on the physiologic and inflammatory responses to SAC were studied in 10 allergic asthmatic subjects in a double-blind, placebo-controlled, crossover protocol.

RESULTS

Prednisone improved baseline FEV(1) by 10% and modestly inhibited the SAC-induced fall in FEV(1) at 30 minutes and at 6 to 8 hours. Five minutes after challenge, levels of histamine, PGD(2), 9alpha,11beta-PGF(2), and thromboxane B(2) increased in bronchoalveolar lavage fluid (median increase, 5- to 14-fold); prednisone did not inhibit these responses. Prednisone inhibited (median decrease, 66%-97%) the total influx of inflammatory cells, specifically eosinophils, basophils, and some subsets of T lymphocytes (CD4, CD45RA, and CD45RO cells) assessed 19 hours after SAC, but it did not inhibit the influx of neutrophils. Increases in soluble E-selectin, kinins, and albumin were also inhibited by the glucocorticoid (median decrease, 36%-74%). Prednisone treatment inhibited the appearance of mRNA, protein, or both for T(H)2 cytokines (IL-4 and IL-5), as well as for IL-2 and transforming growth factor alpha, but did not inhibit increases of immunoreactive GM-CSF in bronchoalveolar lavage fluid.

CONCLUSION

These studies indicate that prednisone suppresses multiple components of allergic airway inflammation, including cell recruitment, adhesion molecule expression or release, airway permeability, and production of cytokines potentially involved in airway immunity or remodeling.