Extensive surface phenotyping of alveolar macrophages in interstitial lung disease

There is increasing evidence implicating activated macrophages in the pathogenesis of interstitial and other lung diseases. We investigated whether there was a unique pattern of cell surface expression that constituted a disease-specific phenotype on alveolar macrophages from patients with interstitial lung disease (ILD). Macrophage cell surface receptor expression of 19 selected markers was assessed by indirect immunofluorescence and flow cytometry in bronchoalveolar lavage (BAL) fluids from patients with idiopathic pulmonary fibrosis (IPF, n = 4), scleroderma (SCL-ILD, n = 14), mild asthma (n = 7), allergy without asthma (n = 2), and normal subjects (n = 9). There was increased expression of adhesion receptors (CD11c, CD29, CD36, CD44, CD49e, CD54), receptors involved in signal transduction and/or inflammation (CD13, CD45, CD53), and other markers (CD9, CD52, CD71, CD98, HLA Class I) on macrophages from ILD patients compared to the non-ILD group. Most markers upregulated on macrophages in ILD were significantly inversely correlated with clinical parameters of disease activity such as FEV(1), FVC, and DL(CO) and positively correlated with numbers of BAL neutrophils and eosinophils. Increased expression of several cell surface markers suggests that activated alveolar macrophages may contribute to the pathophysiology of IPF and SCL-ILD.

Prediction of programmed-temperature retention values of naphthas by artificial neural networks

It is proposed for the first time a method of prediction of the programmed-temperature retention times of components of naphthas in capillary gas chromatography using artificial neural networks. People are used to predict the programmed-temperature retention time using many formulas such as the integral formula, which requires that four parameters must be determined by calculation or experiments. However the results obtained by the formula are not so good to meet the demand of industry. In order to predict retention time accurately and conveniently, artificial neural networks using five-fold cross-validation and leave-20%-out methods have been applied. Only two parameters: density and isothermal retention index were used as input vectors. The average RMS error for predicted values of five different networks was 0.18, whereas the RMS error of predictions by the integral formula was 0.69. Obviously, the predictions by neural networks were much better than predictions by the formula, and neural networks need fewer parameters than the formula. So neural networks can successfully and conveniently solve the problem of predictions of programmed-temperature retention times, and provide useful data for analysis of naphthas in petrochemical industry.

Involvement of cyclin-dependent kinase activities in CD437-induced apoptosis

A novel synthetic retinoid, 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437), is a selective ligand of the RARgamma nuclear receptor. We examined the in vitro effects of CD437 and found that CD437 induces S phase arrest within 24 to 48 h, followed by cell death, in the p53-negative Hep3B and the p53-positive HepG2 human hepatoma cell lines. Based on observations of cellular and nuclear fragmentation, chromatin condensation, and DNA fragmentation, the CD437-mediated cell-killing effect appears to be due to apoptosis. On morphological examination, a number of CD437-treated cells were found to have increased 5- to 10-fold in size and persisted as single giant cells without cell division, while the remainder underwent nuclear division (multiple nuclei) but were unable to complete cytokinesis, and finally all died by apoptosis. In HepG2 cells that possessed wild-type p53, CD437-induced S phase arrest and apoptosis were accompanied by the up-regulation of cyclin A, cyclin B, p53, p21(CIP1/Waf1), Bad, and Bcl-Xs proteins and by a decrease in Bcl-2 protein levels. In Hep3B cells, CD437-mediated S phase arrest and apoptosis were also associated with a concomitant up-regulation of cyclin A, cyclin B, Bad, and Bcl-Xs. However, Hep3B cells did not express p53 or Bcl-2 messages. Olomoucine and roscovitine, the potent p34(cdc2) and CDK2 inhibitors, effectively blocked CD437-mediated cyclin A- and B-dependent kinase activation and prevented CD437-induced cell death. Furthermore, antisense oligonucleotide complementary to cyclin A and B mRNA significantly rescued CD437-induced apoptosis. These findings suggest that activation of cyclin A- and B-dependent kinases is a critical determinant of apoptotic death mediated by CD437.

Computer-aided development of a high-performance liquid chromatographic method for the determination of hydroxyanthraquinone derivatives in Chinese herb medicine rhubarb

With computer simulation predicting separation in reversed-phase gradient elution, a method to separate and determine five hydroxyanthraquinone derivatives having a wide range of polarity in extract of Chinese herbal medicine rhubarb has been developed. The software DryLab was used to model the retention behavior of the compounds as a function of gradient conditions, based on data from two scouting gradient runs. Under the optimized conditions, i.e. column, Zorbax RX-C18, 5 microm, 15x0.46 cm; solvent A, 36 mM triethylamine phosphate (TEAP), pH=2.5; solvent B, ACN; gradient, 36/36/80/80% B at 0/5.5/20.5/25.5 min; flow-rate, 1.00 ml/min; temperature, ambient, the method was successfully applied to monitor the quality of rhubarb from different sources. The effect of sample preparation procedures on extraction efficiency was also examined.

Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone; 3-AP): an inhibitor of ribonucleotide reductase with antineoplastic activity

The enzyme RR catalyzes the conversion of ribonucleoside diphosphates to their deoxyribonucleotide counterparts. RR is critical for the generation of the cytosine, adenine, and guanine deoxyribonucleotide 5'-triphosphate building blocks of DNA, which are present in cells as exceedingly small intracellular pools. Therefore, interference with the function of RR might well result in an agent with significant antineoplastic activity, particularly against rapidly proliferating tumor cells. HUr is the only inhibitor of RR in clinical usage; this agent, however, is a relatively poor inhibitor of the enzyme and has a short serum half-life. Consequently, HUr is a relatively weak anticancer agent. In an effort to develop a more potent inhibitor of RR with utility as an anticancer agent, we have synthesized 3-AP and demonstrated (a) potent inhibition of L1210 leukemia cells in vitro, (b) curative capacity for mice bearing the L1210 leukemia, (c) marked inhibition of RR, and (d) sensitivity of HUr-resistant cells to 3-AP. These findings collectively demonstrate the clinical potential of 3-AP as an antineoplastic agent.

Pharmacodynamics, safety, tolerability, and pharmacokinetics of the 0.8-mg dose of cerivastatin in patients with primary hypercholesterolemia

Cerivastatin is a third generation hydroxy-methyl-glutaryl-Co-enzyme A (HMG-CoA) reductase inhibitor proven to lower low-density lipoprotein (LDL) cholesterol 28% to 31% in patients with primary hypercholesterolemia when given at 0.3 mg/day. This study evaluates the safety, tolerability, pharmacodynamics, and pharmacokinetics of cerivastatin 0.8 mg once daily for 4 weeks. In this randomized, double-blind, placebo-controlled parallel group trial conducted at 2 study centers, 41 patients (63% women) with primary hypercholesterolemia were placed on an American Heart Association Step 1 diet for 4 weeks. Single-blind placebo was administered for the final 2 weeks, before randomization. Patients received cerivastatin 0.8 mg (n = 28) or placebo (n = 13) once each evening for 28 days. Cerivastatin at 0.8 mg daily was well tolerated. No discontinuations occurred during the study. Adverse events were mild and transient. One cerivastatin-treated patient experienced asymptomatic creatinine kinase, 8x the upper limit of normal (ULN) elevation on the last day of the study, which resolved 6 days after the completion of the study. Cerivastatin 0.8 mg daily significantly reduced LDL cholesterol compared with placebo (-44.0 +/- 2.0% vs 2.2 +/- 2.8%, p <0.0001); total cholesterol (-30.8 +/- 1.4% vs 2.6 +/- 2.1%, p <0.0001), triglycerides (-11.2 +/- 5.9% vs 15.9 +/- 8.6%, p <0.02), but did not significantly alter high-density lipoprotein (HDL) cholesterol (3.2 +/- 2.1% vs -1.2 +/- 3.1%, p = NS). The pharmacokinetics of the 0.8-mg dose revealed dose proportional elevations in the 24-hour area under the curve and maximum plasma concentration relative to 0.3- and 0.4-mg doses with no change in time to maximum concentration or the elimination half-life in plasma. The increased efficacy and lack of clinically significant laboratory abnormalities or adverse events demonstrates a need for a large long-term study to confirm the safety and efficacy of this dose of cerivastatin.

Oral bioequivalence of three ciprofloxacin formulations following single-dose administration: 500 mg tablet compared with 500 mg/10 mL or 500 mg/5 mL suspension and the effect of food on the absorption of ciprofloxacin oral suspension

The oral bioequivalence and tolerability of two ciprofloxacin formulations (tablet and suspension) and the effect of food on the absorption of ciprofloxacin oral suspension were investigated. Sixty-eight young, healthy male subjects participated in two separate, randomized, crossover studies. In study 1, ciprofloxacin as a single 500 mg tablet or as 500 mg/10 mL oral suspension was administered in a fasted state on day 1. In study 2, subjects participated in a three-way crossover study in which ciprofloxacin suspension was administered as 500 mg/10 mL in a fasted state, or 500 mg/10 mL with food, or 500 mg/5 mL in a fasted state. Plasma ciprofloxacin concentrations were measured by high-performance liquid chromatography. Standard pharmacokinetic parameters were estimated using non-compartmental methods. In study 1, geometric mean Cmax values of ciprofloxacin following the single 500 mg tablet and 500 mg/10 mL suspension doses were 2.36 and 2.18 mg/L, respectively; corresponding geometric mean t(max) values were 1.1 and 1.6 h, respectively. Geometric mean AUC(0-infinity) values were 12.0 and 11.8 mg x h/L, respectively. In study 2, geometric least squares mean Cmax values following ciprofloxacin 500 mg/10 mL and 500 mg/5 mL suspension during fasted conditions were 1.54 and 1.59 mg/L, respectively. Corresponding geometric least squares mean AUC(0-infinity) values were 7.3 and 8.0 mg x h/L. Administration of ciprofloxacin 500 mg/10 mL suspension, in either a fasted or fed state, was not associated with significant changes in Cmax (1.54 mg/L for fasted vs 1.37 mg/L for fed) or AUC(0-infinity) values (7.28 mg x h/L for fasted vs 8.19 mg x h/L for fed). Each ciprofloxacin formulation was well tolerated for the duration of each study. These studies demonstrated bioequivalence between ciprofloxacin 500 mg tablet and two strengths of ciprofloxacin suspension (500 mg/10 mL and 500 mg/5 mL). Bioavailability was unaltered by food.

Bacterial expression, purification, and characterization of a novel mouse sulfotransferase that catalyzes the sulfation of eicosanoids

Analysis of the nucleotide sequence of a recently cloned mouse sulfotransferase cDNA (clone 679153) revealed the presence in its 3'-untranslated sequence of an AT-rich region which contains four ATTTA motifs and an TTATTTAT-like sequence, commonly found among those encoding inflammation-related proteins. The recombinant enzyme expressed in Escherichia coli and purified to near electrophoretic homogeneity displayed strong sulfotransferase activities toward various prostaglandins, thromboxane B2, and leukotriene E4. These results mark the first discovery of the sulfation of eicosanoids catalyzed by a distinct sulfotransferase.

Structural identification of sulfated tyrosine in human urine

A reliable HPLC method was used for the identification of positional isomerism and stereoisomerism of sulfated tyrosine residues in human urine. Upon separation of human urine by ion-pair HPLC on a reverse-phase column, p-tyrosine-O-sulfate (p-TyrS) was identified. Differentiation of the L and D forms was done by using a column with a chiral stationary phase. It was concluded that L-p-tyrosine (L-p-Tyr) which is the predominant tyrosine isomer in the human body, was sulfated and excreted in human urine as a normal constituent. The sulfated forms of D-p-Tyr and m-Tyr could not be detected under these analytical conditions.

Synthesis of 2'-methylene-substituted 5-azapyrimidine, 6-azapyrimidine, and 3-deazaguanine nucleoside analogues as potential antitumor/antiviral agents

2'-Deoxy-2'-methylene-6-azauridine (5) and 2'-deoxy-2'-methylene-6-azacytidine (8) have been synthesized via a multi-step procedure from 6-azauridine. 2'-Deoxy-2'-methylene-5-azacytidine (14a) and 2'-deoxy-2'-methylene-3-deazaguanosine (19a) and their corresponding alpha-anomers (14b and 19b) have been synthesized by the transglycosylation of 3',5'-O-(1,1,3,3- tetraisopropyldisiloxane-1,3-diyl)-2'-deoxy-2'-methyleneu ridine (12) with silylated 5-azacytosine and silylated N2-palmitoyl-3-deazaguanine, respectively, in the presence of trimethylsilyl trifluoromethanesulfonate as the catalyst in anhydrous dichloroethane, followed by separation of the isomers and deprotection of the blocking groups. These compounds were tested for cytotoxicity against B16F10, L1210, and CCRF-CEM tumor cell lines and for antiviral activity against HIV-1, HSV-1, and HSV-2.

Molecular cloning, expression, and characterization of novel human SULT1C sulfotransferases that catalyze the sulfonation of N-hydroxy-2-acetylaminofluorene

Upon sulfonation, carcinogenic hydroxyarylamines such as N-hydroxy-2-acetylaminofluorene (N-OH-2AAF) can be further activated to form ultimate carcinogens in vivo. Previous studies have shown that a SULT1C1 sulfotransferase is primarily responsible for the sulfonation of N-OH-2AAF in rat liver. In the present study, two novel human sulfotransferases shown to be members of the SULT1C sulfotransferase subfamily based on sequence analysis have been cloned, expressed, and characterized. Comparisons of the deduced amino acid sequence encoded by the human SULT1C sulfotransferase cDNA 1 reveal 63.7, 61.6, and 85.1% identity to the amino acid sequences of rat SULT1C1 sulfotransferase, mouse SULT1C1 sulfotransferase, and rabbit SULT1C sulfotransferase. In contrast, the deduced amino acid sequence of the human SULT1C sulfotransferase 2 cDNA displays 62.9, 63.1, 63.1, and 62.5% identity to the amino acid sequences of the human SULT1C sulfotransferase 1, rat SULT1C1 sulfotransferase, mouse SULT1C1 sulfotransferase, and rabbit SULT1C sulfotransferase. Recombinant human SULT1C sulfotransferases 1 and 2, expressed in Escherichia coli and purified to near electrophoretic homogeneity, were shown to cross-react with the antiserum against the rat liver SULT1C1 sulfotransferase and exhibited sulfonating activities with N-OH-2AAF as substrate. Tissue-specific expression of these novel human SULT1C sulfotransferases were examined by employing the Northern blotting technique. The results provide a foundation for the investigation into the functional relevance of these new SULT1C sulfotransferases in different human tissues/organs.

Clonal disease of natural killer large granular lymphocytes in Taiwan

Lymphoproliferative diseases of large granular lymphocytes (LDGL) may arise from either CD3+ T cells or CD3- natural killer (NK) cells. LDGL with clonal proliferation of large granular lymphocytes (LGL) is defined as LGL leukaemia. The number of patients with NK-LGL leukaemia reported is limited and the pathogenesis of the disease is not yet clear. From 1991 to 1998 six patients with cytogenetically proved clonal disease of NK-LGL were identified in our institute. All were seropositive for Epstein-Barr virus (EBV). EBV RNA or DNA could be detected in LGL from four patients by EBV in situ hybridization or Southern blot analysis. Most patients ran an aggressive clinical course and five died of the disease. Nonrandom clonal chromosomal abnormalities, including duplication of 1q, rearrangement at 3q and loss of chromosomes Y, 13 or 10, were noted in the six patients from this study and in eight from the literature. The implications of these recurrent cytogenetic aberrations in the development and progression of the disease deserve further studies.

Substrate specificity of human monoamine (M)-form phenol sulfotransferase: preparation and analysis of Dopa 3-O-sulfate and Dopa 4-O-sulfate

Upon two-dimensional thin-layer separation, the sulfated L-3, 4-dihydroxyphenylalanine (L-DopaS) generated enzymatically was found to co-migrate with only one of the two ninhydrin-stained spots corresponding to the two sulfated forms (3-O-sulfate and 4-O-sulfate) of synthetic L-DopaS. To clarify precisely the identity of the enzymatically generated L-DopaS, the two sulfated forms of synthetic L-DopaS were separated and purified using high performance liquid chromatography. Purified L-Dopa 3-O-sulfate and L-Dopa 4-O-sulfate were identified by 1H-nuclear magnetic resonance (NMR) spectrometry and used as standards in the analysis of the L-DopaS generated during metabolic labeling of HepG2 human hepatoma cells or enzymatic assay using recombinant human monoamine (M)-form phenol sulfotransferase. The results obtained demonstrated unequivocally the generation of L-Dopa 3-O-sulfate, indicating the specificity of the M-form phenol sulfotransferase being for the meta-hydroxyl group of L-Dopa.

Molecular cloning, expression, and characterization of a novel mouse liver SULT1B1 sulfotransferase

A mouse liver homogenate was shown to contain enzymatic activities catalyzing the sulfation of 3,4-dihydroxyphenylalanine (Dopa) and tyrosine isomers with a pH optimum of 8.25. Western blot analysis revealed a 34 kDa protein exhibiting immunologic cross-reactivity to antiserum against rat liver SULT1B1 sulfotransferase. By employing the reverse transcriptase-polymerase chain reaction (RT-PCR) technique, a 910-base pair product encoding the putative mouse liver SULT1B1 sulfotransferase was obtained. Using this PCR product as a probe, a cDNA containing the entire open reading frame of the mouse liver SULT1B1 sulfotransferase was cloned from a mouse liver Lambda ZAP cDNA library. The nucleotide sequence indicated it is a new enzyme. The deduced amino acid sequence exhibited 87.6, 72.3, 55.9, 54.2, 52.8, 51.1, and 49.4% identity to the amino acid sequences of the rat liver SULT1B1 sulfotransferase, human thyroid hormone sulfotransferase, mouse phenol sulfotransferase, rat liver phenol sulfotransferase, rat liver hydroxyarylamine sulfotransferase, mouse estrogen sulfotransferase, and rat estrogen sulfotransferase. Upon transfection of COS-7 cells with an expression vector (pcDNA3) harboring the cDNA encoding this new enzyme, a 34 kDa protein exhibiting immunologic cross-reactivity to antiserum against the rat liver SULT1B1 sulfotransferase was expressed. The recombinant sulfotransferase exhibited enzymatic activities toward Dopa and tyrosine isomers, as well as dopamine and 3,3',5-triiodo-L-thyronine. Northern blot analyses indicated the SULT1B1 sulfotransferase was predominantly expressed in liver, but not in the other ten mouse organs examined. Furthermore, the enzyme was found to be expressed in a developmental stage-dependent manner, being at a very low level in liver samples from 1-day-old mice and then gradually increasing to the maximum level in liver samples from 4-week-old mice.

Molecular cloning, expression, and functional characterization of novel mouse sulfotransferases

Nucleotide sequences of two mouse cDNAs encoding new sulfotransferase enzymes were determined. Analysis of the deduced amino acid sequences revealed that one represents a novel member of the phenol sulfotransferase family and the other is highly homologous to human SULT2B1 hydroxysteroid sulfotransferases. The recombinant enzymes, transiently expressed in COS-7 cells, were characterized with respect to their substrate specificity using a variety of substrates for different types of sulfotransferases. The tissue-specific expression of these two new mouse sulfotransferases was examined by Northern blot analysis.

cDNA cloning, expression, and characterization of the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate kinase enzyme

A cDNA encoding the human bifunctional ATP sulfurylase/adenosine 5'-phosphosulfate (APS) kinase was cloned and sequenced. The enzyme contains an APS kinase domain in its N-terminal portion and an ATP sulfurylase domain in its C-terminal portion. Recombinant full-length enzyme and its constituent APS kinase and ATP sulfurylase domains were individually expressed, purified, and shown to have their respective enzymatic activities.

Localization and functional analysis of the substrate specificity/catalytic domains of human M-form and P-form phenol sulfotransferases

Human monoamine (M)-form and simple phenol (P)-form phenol sulfotransferases (PSTs), which are greater than 93% identical in their primary sequences, were used as models for investigating the structural determinants responsible for their distinct substrate specificity and other enzymatic properties. A series of chimeric PSTs were constructed by reciprocal exchanges of DNA segments between cDNAs encoding M-form and P-form PSTs. Functional characterization of the recombinant wild-type M-form, P-form, and chimeric PSTs expressed in Escherichia coli and purified to homogeneity revealed that internal domain-spanning amino acid residues 84-148 contain the structural determinants for the substrate specificity of either M-form or P-form PST. Data on the kinetic constants (Km, Vmax, and Vmax/Km) further showed the differential roles of the two highly variable regions (Region I spanning amino acid residues 84-89 and Region II spanning amino acid residues 143-148) in substrate binding, catalysis, and sensitivity to the inhibition by 2,6-dichloro-4-nitrophenol. In contrast to the differential sulfotransferase activities of M-form and P-form PSTs toward dopamine and p-nitrophenol, the Dopa/tyrosine sulfotransferase activities were found to be restricted to M-form, but not P-form, PST. Furthermore, the variable Region II of M-form PST appeared to play a predominant role in determining the Dopa/tyrosine sulfotransferase activities of chimeric PSTs. Kinetic studies indicated the role of manganese ions in dramatically enhancing the binding of D-p-tyrosine to wild-type M-form PST. Taken together, these results pinpoint unequivocally the sequence encompassing amino acid residues 84-148 to be the substrate specificity/catalytic domain of both M-form and P-form PSTs and indicate the importance of the variable Regions I and II in determining their distinct enzymatic properties.

Direct assessment of small airways reactivity in human subjects

Our knowledge of airways reactivity to inflammatory agonists is derived predominantly from tests dominated by large airway responsiveness. To determine directly, the histamine responsiveness of the smallest airways, eight normal and 11 asymptomatic asthmatic subjects were studied utilizing a wedged bronchoscope technique. A fiberoptic bronchoscope was wedged in the anterior segment of the right upper lobe and a double-lumen catheter was advanced through the working channel to its tip. With a constant flow of gas (5% CO2 in air) through one lumen of the catheter, pressure at the tip of the bronchoscope was measured with the subject breath-holding at FRC. Peripheral airways resistance (Rp) was measured at baseline and after saline, histamine (10, 50, 100 mg/ml) and isoproterenol (2 mg/ml) challenge through the bronchoscope. Baseline Rp of asthmatics (0.041 +/- 0.015 cm H2O/ml/min; mean +/- SE) was significantly greater than normal subjects (0.011 +/- 0.003 cm H2O/ml/min; p = 0.019). The log of the concentration of histamine that caused a 100% increase in peripheral airways response was greater in the normal subjects than in the asthmatic subjects (p = 0.0114) and correlated with whole lung responsiveness to histamine in asthmatics (r = 0.847, p < 0.05). Isoproterenol reversed completely the increase in Rp in normal subjects but not asthmatic subjects. The results of this study demonstrate that the resistance of the smallest peripheral airways, when measured directly, increased when challenged locally with histamine in both normal subjects and asthmatic subjects. However, the peripheral airways responsiveness was significantly enhanced in asthmatic subjects relative to normal controls.

Ragweed-specific antibodies in bronchoalveolar lavage fluids and serum before and after segmental lung challenge: IgE and IgA associated with eosinophil degranulation

BACKGROUND

Migration of eosinophils and release of eosinophil degranulation products into bronchoalveolar lavage fluid is a consistent finding in studies of late responses to allergen challenge in the lung. However, the mechanism of eosinophil activation and release of eosinophil products in vivo is unclear.

OBJECTIVE

We investigated the hypothesis that antigen-specific IgG, IgA, secretory IgA, or IgE is responsible for the eosinophil activation observed in the late-phase pulmonary reaction.

METHODS

Ragweed-specific IgE, IgA, secretory IgA, and IgG were measured by monoclonal antibody-based immunoassays in bronchoalveolar lavage (BAL) fluid and in serum from 19 asthmatic subjects allergic to ragweed and six healthy nonallergic control subjects before and 20 hours after segmental lung challenge with ragweed extract. Eosinophil cationic protein (ECP) was also measured in BAL fluid as a marker of eosinophil activation.

RESULTS

Most allergic asthmatic subjects had detectable levels of ragweed-specific IgE, IgA, and IgG in their serum and BAL fluid, whereas normal subjects had ragweed-specific IgA with no ragweed-specific IgE and little ragweed-specific IgG. IgA was the dominant ragweed-specific antibody isotype in BAL fluids. Ragweed-specific sIgA (r[s] = 0.52, p = 0.02) and IgA (r[s] = 0.50, p = 0.03) in BAL fluid after segmental lung challenge were significantly correlated with ECP. Ragweed-specific IgE and IgA in serum also correlated with ECP (r[s] = 0.74, p < 0.001 and r[s] = 0.48, p = 0.04, respectively).

CONCLUSIONS

The correlation of allergen-specific IgA and IgE antibody levels with ECP as a marker of eosinophil degranulation suggests an important role for IgE antibodies in allergic pulmonary inflammation and a potential role for antigen-specific IgA in eosinophil degranulation in the lung after antigen challenge.

The benefit and risk of postmastectomy radiation therapy in patients with high-risk breast cancer

To evaluate the efficacy of postmastectomy radiation therapy (PMRT) for prophylaxis against locoregional recurrence in high-risk breast cancer patients, and the rate of complication associated with such treatment, we retrospectively reviewed 79 breast cancers in 78 patients, who were given therapy (PMRT) between April 1990 and March 1995. Radiation doses were 46-50 Gy in 2-Gy fractions. High-risk factors included primary tumor (> or = 5 cm) in 19 (24.1%) patients, positive axillary lymph nodes (> or = 4) in 56 (70.9%) patients, positive or close (< or = 2 mm) surgical margins in 14 (17.7%) patients, and central or inner quadrant tumor with positive axillary nodes and lymphovascular invasion in seven (8.9%) patients. Adjuvant chemotherapy was also given to 69 of 78 (88.5%), patients and hormonal therapy to 41 of 78 (53.7%) patients. The median follow-up time was 25 months (range, 7-66 months) after mastectomy. Our study revealed that locoregional failure as the first site of failure occurred in only one of 78 (1.3%) patients. Relapse-free survival at 3 years was 67.7% [95% confidence interval (CI), 52.0-81.3], and overall survival was 76.9% (95% CI, 63.3-90.6). The incidence of radiological evidence of lung fibrosis increased significantly in patients whose internal mammary chain was included in the radiation field. The occurrence of lung fibrosis can be reduced by changing radiation treatment technique and keeping central lung distance (CLD) of tangential field to < or = 2.8 cm in tangential field technique or < or = 1.4 cm in tangential with a separate internal mammary field technique. We concluded that the risk of locoregional recurrence in high-risk breast cancer patients can be much reduced by PMRT. With careful selection of radiation treatment fields, radiotherapy technique, and limitation of CLD to < or = 2.8 cm in tangential technique or < or = 1.4 cm in separate technique, the risk of symptomatic radiation pneumonitis is minimal. PMRT should be recommended for breast cancer patients who are at high risk for locoregional recurrence.

Protein SRP54 of human signal recognition particle: cloning, expression, and comparative analysis of functional sites

Signal recognition particle (SRP) plays a critical role in the targeting of secretory proteins to cellular membranes. An essential component of SRP is the protein SRP54, which interacts not only with the nascent signal peptide, but also with the SRP RNA. To understand better how protein targeting occurs in the human system, the human SRP54 gene was cloned, sequenced, and the protein was expressed in bacteria and insect cells. Recombinant SRP54 was purified from both sources. The protein bound to SRP RNA in the presence of protein SRP19, and associated with the signal peptide of in vitro translated pre-prolactin. Comparative sequence analysis of human SRP54 with homologs from all three phylogenetic domains was combined with high-stringency protein secondary structure prediction. A conserved RNA-binding loop was predicted in the largely helical M-domain of SRP54. Contrary to general belief, the unusually high number of methionine residues clustered outside the predicted helices, thus indicating a mechanism of signal peptide recognition that may involve methionine-rich loops.

Preoperative concurrent chemotherapy and radiotherapy in rectal cancer patients

The management of rectal cancer has changed significantly in recent years. The key end-point is no longer survival but rather preservation of sphincter function with improved quality of life. Preoperative radiation can not only render a low-lying rectal tumor amenable to sphincter-preserving surgery but has also been reported to give better local control and lower toxicity than postoperative radiotherapy. From October 1991 through July 1996, 46 patients with local advanced or low-lying rectal cancer were treated with preoperative high-dose radiotherapy and concurrent chemotherapy. All patients underwent pelvic radiotherapy with 5,000 to 5,400 cGy in 25 to 27 fractions. Chemotherapy was given concomitantly and consisted of two courses of 5-fluorouracil (5-FU) at 1,000 mg/m2 for 4 days in week 1 and week 5 plus mitomycin C 10 mg/m2 single bolus on day 1 of week 1. In 30 patients, postoperative adjuvant chemotherapy with 5-FU and levamisole weekly was also given, for a total of 12 months. The most common acute toxicity was grade 1 to 2 diarrhea and tenesmus during radiation or soon afterward. Only five of the 46 patients experienced symptomatic grade 3 acute toxicity. Forty-two patients underwent subsequent surgery 6 to 8 weeks after concurrent chemoradiotherapy. Pathologic examination disclosed complete tumor regression in eight patients and microscopic residual disease in 13 patients after preoperative chemoradiation. Of the 42 patients who completed the intended treatments, only one had local recurrence. The sphincter was preserved in 21 of the 26 patients in whom the tumor was located within 5 cm above the anal verge. Twelve of the 16 evaluable patients had good to excellent sphincter function. The 2-year overall survival rate was 93% and the disease-free survival was 81%. Our findings indicate that preoperative concurrent chemoradiotherapy not only allows low-lying rectal tumors to be resected while preserving sphincter function but also results in good local control and acceptable toxicity.

Overexpression of the multidrug resistance genes mdr1, mdr3, and mrp in L1210 leukemia cells resistant to inhibitors of ribonucleotide reductase

L1210 MQ-580 is a murine leukemia cell line resistant to the cytotoxic activity of the alpha-(N)-heterocyclic carboxaldehyde thiosemicarbazone class of inhibitors of ribonucleotide reductase. The line is cross-resistant to etoposide, daunomycin, and vinblastine. L1210 MQ-580 cells expressed 8-fold resistance to 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP), a relatively newly developed inhibitor of ribonucleotide reductase. The accumulation of [14C]3-AP by L1210 MQ-580 cells was 5- to 6-fold less than by parental L1210 cells. An increased rate of efflux of 3-AP was responsible for the lower steady-state concentration of 3-AP in resistant cells. In reverse transcription-polymerase chain reaction assays, L1210 MQ-580 cells were found to overexpress the multidrug resistance genes mdr1, mdr3, and mrp, but not the mdr2 gene, compared with parental L1210 cells. Measurement of the steady-state concentration of doxorubicin, a potential substrate for both the mdr and mrp gene products, demonstrated that L1210 MQ-580 cells accumulated 4-fold less anthracycline than parental cells. These findings indicate that drug efflux is a major determinant of the pattern of cross-resistance of L1210 MQ-580 cells. To extrapolate these observations to the human homologues of the mdr1, mdr3, and mrp murine genes, the effects of 3-AP were measured in L1210/VMDRC0.06 and NIH3T3 36-8-32 cells transfected with human MDR1 and MRP cDNAs, respectively. The transfectants were 2- to 3-fold resistant to the cytotoxic effects of 3-AP and accumulated less [14C]3-AP than their parental mock-transfected counterparts. Moreover, the cytotoxic activity of 3-AP was significantly greater in two double mrp gene knockout cell lines than in parental W 9.5 embryonic stem cells. Thus, the results suggest that 3-AP is a substrate for both the P-glycoprotein and MRP and that baseline MRP expression has the capacity to exert a protective role against the toxicity of this agent.

Characterization of bovine heart sulfotransferase catalyzing the sulfation of tyrosine-containing peptides

Using [35S]PAPS as the sulfate donor, we have detected a sulfotransferase from bovine heart which catalyzes the sulfation of tyrosine-containing peptides. The enzyme displayed optimal activity at pH 5.75 and 35 degrees C in a one-hour reaction. The addition of 10 mM Mn2+ or Co2+ to the reaction mixture increased the sulfotransferase activity by 3.4- and 3.5-fold, respectively. In contrast, the maximum increment stimulated by Mg2+ was only 1.75-fold at 15 mM concentration, and instead of exerting an enhancement effect, Ca2+ was found to be a potent inhibitor. The addition of 50 mM NaF to the reaction mixture resulted in an increase in sulfotransferase activity of 3.3-fold. The K(m) for 3'-phosphoadenosine 5'-phosphosulfate (PAPS) was determined to be 2 microM at a constant 0.5 mM Boc-Glu-Asp-Tyr-Val. Among the 10 peptides tested as substrates, Boc-Glu-Asp-Tyr-Val and Boc-Asp-Asp-Tyr-Val provided the highest activities.