Squamous Cell Carcinoma Antigen for Monitoring Cervical Cancer

The tumour-associated antigen was determined in the plasma of patients with squamous cell carcinoma (SCC) of the uterine cervix by radioimmunoassay. Setting a limit of 2 ng/ml, levels were abnormal in 13.4% of healthy controls, in 14% of patients with carcinoma in situ and in 62% of patients with invasive cervical SCC. The incidence of elevated SCC antigen levels and the absolute antigen plasma concentration were dependent upon the tumour load, increasing significantly with advanced stage disease. Abnormal SCC antigen values in operable cervical cancer declined to normal within one week after radical hysterectomy with pelvic lymphadenectomy. In cases of radiotherapy antigen values took 4-6 weeks after the start of treatment to return to normal. The success of both treatment modalities was announced by an early rise in the SCC antigen in the initial phase of therapy, followed by normalisation. After successful primary treatment and a complete remission during further follow-up SCC antigen in plasma was only increased in 3.8% of the cases. Retrospective evaluations in ten patients with progressive disease showed the reappearance of abnormal SCC titers and further increase preceeding the clinically detectable relapse or progression, with a median interval of 8 weeks. The present study indicates that SCC antigen determination is not useful for the early diagnosis of cervical cancer, but it is a potential means for monitoring the efficacy of individual anticancer therapy of SCC of the uterine cervix and for detecting recurrent disease.

Ca 15.3 as a Tumour Marker in Breast Cancer

CA 15.3 is an antigenic determinant associated with human mammary carcinomas. Two murine monoclonal antibodies have been raised against the determinants, and an immunoradiometric assay (IRMA-Kit, Centocor, USA) has been developed to determine the antigen levels in plasma of cancer patients. Based on the 99% confidence limit of healthy women, plasma values above 30 U/ml are considered abnormal. Plasma samples from 357 women were examined in the present study. Healthy females (n = 84) ranged below the cut-off level between < 10 and 29 U/ml. Higher values were found in 12.5% of benign breast diseases and in 23.6% of breast cancer patients, including all stages. Depending on the stage of the disease, there were elevated levels in 11% of operable breast cancer patients preoperatively, in 7% of the cases with no evidence of disease after primary treatment and in 63.5% ofpatients with disseminated mammary carcinoma. In metastasized breast cancer the frequency and the degree of abnormal titers were closely related to the extent of the metastatic disease. Follow-up examinations of 63 patients under cytotoxic therapy showed CA 15.3 changes correlating well with the clinical course in up to 90% of the antigen positive cases. The present data indicate that CA 15.3 may be useful in the surveillance of breast cancer patients. However in our study one third of the patients with metastatic breast cancer did not show any increase in CA 15.3 and must be regarded as antigen negative.

Die Kristallstruktur von PPh3Me[NbOCl4(CH3CN)] / The Crystal Structure of PPh3Me[NbOCl4(CH3CN)]

The X-ray structure of PPh3Me[NbOCl4(CH3CN)] at 210 K was solved (space group P1̄, two formula units per unit cell, a = 1173.5(5), b = 1130.1(4), c = 946.8(3) pm, α = 97.70(4), β = 93.57(3), γ = 78.62(3)°, 3688 inde­pendent reflexions, R = 0.025).

The material consists of cations [P(C6H5)3CH3]⊕ and anions [NbOCl4(CH3CN)]⊖. The nitrogen atom of the acetonitrile solvate molecule is coordinated to the niobium centre in the trans-position to the oxo ligand; the NbO bond length of 169 pm corresponds to a double bond.

Highly sensitive and fast detection of propane-butane using a 3 μm quantum cascade laser

A mid-IR optical analyzer based on a 3 μm Fabry-Perot quantum cascade laser has been developed for ultrafast detection of aerosol propellants, such as propane and butane. Given the laser emission bandwidth of 35 cm(-1), the system is spectrally well-matched to the C-H vibrational band of hydrocarbons, it is insusceptible to water interference, and stable enough to operate without wavelength scanning. Thus, it offers both high sensitivity and speed, reaching 1 ppm precision within a measurement time of 10 ms. The performance of the instrument is evaluated with an industrial demonstrator for aerosol cans leak testing, confirming that, in compliance with international directives, it can detect leaks of 1.2×10(-4) slpm at a rate of 500 cans per minute.

Development of a nondestructive leak testing method utilizing the head space analyzer for ampoule products containing ethanol-based solutions

The application of a head space analyzer for oxygen concentration was examined to develop a novel ampoule leak test method. Studies using ampoules filled with ethanol-based solution and with nitrogen in the headspace demonstrated that the head space analysis (HSA) method showed sufficient sensitivity in detecting an ampoule crack. The proposed method is the use of HSA in conjunction with the pretreatment of an overpressurising process known as bombing to facilitate the oxygen flow through the crack in the ampoule. The method was examined in comparative studies with a conventional dye ingress method, and the results showed that the HSA method exhibits sensitivity superior to the dye method. The results indicate that the HSA method in combination with the bombing treatment provides potential application as a leak test for the detection of container defects not only for ampoule products with ethanol-based solutions, but also for testing lyophilized products in vials with nitrogen in the head space.

LAY ABSTRACT

The application of a head space analyzer for oxygen concentration was examined to develop a novel ampoule leak test method. The proposed method is the use of head space analysis (HSA) in conjunction with the pretreatment of an overpressurising process known as bombing to facilitate oxygen flow through the crack in the ampoule for use in routine production. The result of the comparative study with a conventional dye leak test method indicates that the HSA method in combination with the bombing treatment can be used as a leak test method, enabling detection of container defects.

Potent family-18 chitinase inhibitors: x-ray structures, affinities, and binding mechanisms

Six novel inhibitors of Vibrio harveyi chitinase A (VhChiA), a family-18 chitinase homolog, were identified by in vitro screening of a library of pharmacologically active compounds. Unlike the previously identified inhibitors that mimicked the reaction intermediates, crystallographic evidence from 14 VhChiA-inhibitor complexes showed that all of the inhibitor molecules occupied the outer part of the substrate-binding cleft at two hydrophobic areas. The interactions at the aglycone location are well defined and tightly associated with Trp-397 and Trp-275, whereas the interactions at the glycone location are patchy, indicating lower affinity and a loose interaction with two consensus residues, Trp-168 and Val-205. When Trp-275 was substituted with glycine (W275G), the binding affinity toward all of the inhibitors dramatically decreased, and in most structures two inhibitor molecules were found to stack against Trp-397 at the aglycone site. Such results indicate that hydrophobic interactions are important for binding of the newly identified inhibitors by the chitinase. X-ray data and isothermal microcalorimetry showed that the inhibitors occupied the active site of VhChiA in three different binding modes, including single-site binding, independent two-site binding, and sequential two-site binding. The inhibitory effect of dequalinium in the low nanomolar range makes this compound an extremely attractive lead compound for plausible development of therapeutics against human diseases involving chitinase-mediated pathologies.

Activation of the Raf-MEK-ERK pathway is required for neutrophil extracellular trap formation

The signaling mechanisms leading to the formation of neutrophil extracellular traps (NETs), relevant in infections, sepsis and autoimmune diseases, are poorly understood. Neutrophils are not amenable to studies with conventional genetic techniques. Using a new chemical genetic analysis we show that the Raf-MEK-ERK pathway is involved in NET formation through activation of NADPH oxidase and upregulation of antiapoptotic proteins. We identify potential targets for drugs addressing NET-associated diseases.

Hill coefficients, dose-response curves and allosteric mechanisms

Hill coefficients (n(H)) derived from four parameter logistic fits to dose-response curves were compared to calculated realistic reaction schemes and related to experimental data: (1) Hill coefficients may give information on the number of interacting sites but cannot distinguish between competitive, non-competitive or ortho-, iso-, or allosteric mechanisms. (2) For enzymatic dose-inhibition curves, Hill coefficients smaller than one do not indicate anticooperative binding but show that at least one ternary complex has enzymatic activity. (3) Hill coefficients different from one are proof for multiple ligand binding. The large variations of reported Hill coefficients corresponds to multiple allosteric binding, where induced conformational changes cause loss of the active conformation. Such a denaturation mechanism is in stark contrast to the desired specificity of drugs. The discussion is open.

Substrate binding modes and anomer selectivity of chitinase A from Vibrio harveyi

High-performance liquid chromatography mass spectrometry (HPLC MS) was employed to assess the binding behaviors of various substrates to Vibrio harveyi chitinase A. Quantitative analysis revealed that hexaNAG preferred subsites −2 to +2 over subsites −3 to +2 and pentaNAG only required subsites −2 to +2, while subsites −4 to +2 were not used at all by both substrates. The results suggested that binding of the chitooligosaccharides to the enzyme essentially occurred in compulsory fashion. The symmetrical binding mode (−2 to +2) was favored presumably to allow the natural form of sugars to be utilized effectively. Crystalline α chitin was initially hydrolyzed into a diverse ensemble of chitin oligomers, providing a clear sign of random attacks that took place within chitin chains. However, the progressive degradation was shown to occur in greater extent at later time to complete hydrolysis. The effect of the reducing-end residues were also investigated by means of HPLC MS. Substitutions of Trp275 to Gly and Trp397 to Phe significantly shifted the anomer selectivity of the enzyme toward β substrates. The Trp275 mutation modulated the kinetic property of the enzyme by decreasing the catalytic constant (k_cat) and the substrate specificity (k_cat/K_m) toward all substrates by five- to tenfold. In contrast, the Trp397 mutation weakened the binding strength at subsite (+2), thereby speeding up the rate of the enzymatic cleavage toward soluble substrates but slowing down the rate of the progressive degradation toward insoluble chitin.

Transient binding patches: a plausible concept for drug binding

Dose–response curves for inhibitors (drugs) generally are analyzed by means of four-parameter fits, yielding IC₅₀, background, amplitude, and Hill coefficient. Hill coefficients ≠1 contradict 1:1 competition. If binding of substrates to proteins is a stepwise process where initial binding to initial locations (patches) leads to strong binding on defined sites, then drugs (non-endogenous inhibitors) may bind to those presumably larger patches and need not follow a 1:1 stoichiometry for specific inhibition. This concept was translated into three computable models and successfully fitted to 1,282 phosphatase dose–response curves. The models only required four parameters, namely, the equilibrium dissociation constant K_D(1) of the first inhibitor binding step, background, amplitude, and a compound interaction factor to quantify the interaction of inhibitors on those patches. Binding of one established inhibitor to the vaccinia virus VH1-related (VHR) phosphatase was directly measured with microcalorimetry, confirming multiple inhibitor binding with equilibrium constants obtained from corresponding inhibition curves.

How to identify a pharmacophore

The inhibition of chitinases by argifin and progressively dissected analogs had been studied by a combination of kinetic and crystallographic methods (Andersen et al., 2008). This work also leads to a general understanding of structure-activity relationships for inhibitors with one distinct pharmacophor.

Optimization of three- and four-component reactions for polysubstituted piperidines: application to the synthesis and preliminary biological screening of a prototype library

Several solid- and solution-phase strategies were evaluated for the preparation of libraries of polysubstituted piperidines of type 7 using the tandem aza[4+2]cycloaddition/allylboration multicomponent reaction between 1-aza-4-boronobutadienes, maleimides, and aldehydes. A novel four-component variant of this chemistry was developed in solution phase, and it circumvents the need for pre-forming the azabutadiene component. A parallel synthesis coupled with compound purification by HPLC with mass-based fraction collection allowed the preparation of a library of 944 polysubstituted piperidines in a high degree of purity suitable for biological screening. A representative subset of 244 compounds was screened against a panel of phosphatase enzymes, and despite the modest levels of activity obtained, this study demonstrated that piperidines of type 7 display the right physical properties (e.g., solubility) to be assayed effectively in high-throughput enzymatic tests.

Drosophila photoreceptors express cysteine peptidase tan

The Drosophila mutant tan (t) shows reciprocal pigmentation defects compared with the ebony (e) mutant. Visual phenotypes, however, are similar in both flies: Electroretinogram (ERG) recordings lack "on" and "off" transients, an indication of impaired synaptic transmission to postsynaptic cells L1 and L2. Cloning of tan revealed transcription of the gene in the retina, apparently in photoreceptor cells. We expressed Tan in Escherichia coli and confirmed by Western blotting and mass spectroscopic analyses that Tan is expressed as preprotein, followed by proteolytic cleavage into two subunits at a conserved --Gly--Cys-- motif like its fungal ortholog isopenicillin-N N-acyltransferase (IAT). Tan thus belongs to the large family of cysteine peptidases. To discriminate expression of Tan and Ebony in retina and optic neuropils, we raised antisera against specific Tan peptides. Testing for colocalization with GMR-driven n-Syb-GFP labeling revealed that Tan expression is confined to the photoreceptor cells R1-R8. A close proximity of Tan and Ebony expression is evident in lamina cartridges, where three epithelial glia cells envelop the six photoreceptor terminals R1-R6. In the medulla, R7/R8 axonal terminals appeared lined up side by side with glial extensions. This local proximity supports a model for Drosophila visual synaptic transmission in which Tan and Ebony interact biochemically in a putative histamine inactivation and recycling pathway in Drosophila.

Brunsvicamides A−C: Sponge-Related Cyanobacterial Peptides with Mycobacterium tuberculosis Protein Tyrosine Phosphatase Inhibitory Activity

The cyanobacterium Tychonema sp. produces the new cyclic hexapeptides brunsvicamide A-C (1-3). Brunsvicamide B (2) and C (3) selectively inhibit the Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB), a potential drug target for tuberculosis therapy for which no inhibitors are known to date. Brunsvicamide C contains an N-methylated N'-formylkynurenine moiety, a unique structural motif in cyclic peptides. The new peptides are related to the sponge-derived mozamides, supporting the suggestion that secondary metabolites of certain marine invertebrates are produced by associated microorganisms. Thus, microorganisms phylogenetically related to symbionts of marine invertebrates can be judged as a means to supply "marine-like" compounds for drug development.

Discovery of protein phosphatase inhibitor classes by biology-oriented synthesis

Protein phosphatases have very recently emerged as important targets for chemical biology and medicinal chemistry research, and new phosphatase inhibitor classes are in high demand. The underlying frameworks of natural products represent the evolutionarily selected fractions of chemical space explored by nature so far and meet the criteria of relevance to nature and biological prevalidation most crucial to inhibitor development. We refer to synthesis efforts and compound collection development based on these criteria as biology-oriented synthesis. For the discovery of phosphatase inhibitor classes by means of this approach, four natural product-derived or -inspired medium-sized compound collections were synthesized and investigated for inhibition of the tyrosine phosphatases VE-PTP, Shp-2, PTP1B, MptpA, and MptpB and the dual-specificity phosphatases Cdc25A and VHR. The screen yielded four unprecedented and selective phosphatase inhibitor classes for four phosphatases with high hit rates. For VE-PTP and MptpB the first inhibitors were discovered. These results demonstrate that biology-oriented synthesis is an efficient approach to the discovery of new compound classes for medicinal chemistry and chemical biology research that opens up new opportunities for the study of phosphatases, which may lead to the development of new drug candidates.

Polyketides from the marine-derived fungus Ascochyta salicorniae and their potential to inhibit protein phosphatases

Chemical investigation of the marine fungus Ascochyta salicorniae led to the isolation of two new epimeric compounds, ascolactones A (1) and B (2), in addition to the structurally-related polyketides hyalopyrone (3), ascochitine (4), ascochital (5) and ascosalipyrone (6). The absolute configurations of the epimeric compounds 1 and 2 were assigned as (1R,9R) and (1S,9R), respectively, through simulation of the chiroptical properties using quantum-chemical CD calculations, and chiral GC-MS subsequent to oxidative cleavage (Baeyer-Villiger oxidation) of the side chain. In silico screening using the PASS software identified some of the A. salicorniae compounds (1-6) as potential inhibitors of protein phosphatases. Compound was found to inhibit the enzymatic activity of MPtpB with an IC(50) value of 11.5 microM.

3-Substituted indolizine-1-carbonitrile derivatives as phosphatase inhibitors

In the course of studies directed toward the discovery of novel scaffolds for medicinal application, we synthesized a series of 3-substituted indolizine-1-carbonitrile derivatives. Some of them displayed activity against MPtpA/MPtpB phosphatases which are involved in infectious diseases. We report here the solid-phase synthesis and antiphosphatase activity of a series of indolizines.

Expression, purification, crystallization and preliminary crystallographic analysis of chitinase A from Vibrio carchariae

Chitinase A of Vibrio carchariae was expressed in Escherichia coli M15 host cells as a 575-amino-acid fragment with full enzymatic activity using the pQE60 expression vector. The yield of the highly purified recombinant protein was approximately 70 mg per litre of bacterial culture. The molecular mass of the expressed protein was determined by HPLC/ESI-MS to be 63 770, including the hexahistidine tag. Crystals of recombinant chitinase A were grown to a suitable size for X-ray structure analysis in a precipitant containing 10%(v/v) PEG 400, 0.1 M sodium acetate pH 4.6 and 0.125 M CaCl2. The crystals belonged to the tetragonal space group P422, with two molecules per asymmetric unit and unit-cell parameters a = b = 127.64, c = 171.42 A. A complete diffraction data set was collected to 2.14 A resolution using a Rigaku/MSC R-AXIS IV++ detector system mounted on an RU-H3R rotating-anode X-ray generator.

Enzymatic properties of wild-type and active site mutants of chitinase A from Vibrio carchariae, as revealed by HPLC-MS

The enzymatic properties of chitinase A from Vibrio carchariae have been studied in detail by using combined HPLC and electrospray MS. This approach allowed the separation of alpha and beta anomers and the simultaneous monitoring of chitooligosaccharide products down to picomole levels. Chitinase A primarily generated beta-anomeric products, indicating that it catalyzed hydrolysis through a retaining mechanism. The enzyme exhibited endo characteristics, requiring a minimum of two glycosidic bonds for hydrolysis. The kinetics of hydrolysis revealed that chitinase A had greater affinity towards higher Mr chitooligomers, in the order of (GlcNAc)6 > (GlcNAc)4 > (GlcNAc)3, and showed no activity towards (GlcNAc)2 and pNP-GlcNAc. This suggested that the binding site of chitinase A was probably composed of an array of six binding subsites. Point mutations were introduced into two active site residues - Glu315 and Asp392 - by site-directed mutagenesis. The D392N mutant retained significant chitinase activity in the gel activity assay and showed approximately 20% residual activity towards chitooligosaccharides and colloidal chitin in HPLC-MS measurements. The complete loss of substrate utilization with the E315M and E315Q mutants suggested that Glu315 is an essential residue in enzyme catalysis. The recombinant wild-type enzyme acted on chitooligosaccharides, releasing higher quantities of small oligomers, while the D392N mutant favored the formation of transient intermediates. Under standard hydrolytic conditions, all chitinases also exhibited transglycosylation activity towards chitooligosaccharides and pNP-glycosides, yielding picomole quantities of synthesized chitooligomers. The D392N mutant displayed strikingly greater efficiency in oligosaccharide synthesis than the wild-type enzyme.

Expression and refolding of Omp38 from Burkholderia pseudomallei and Burkholderia thailandensis, and its function as a diffusion porin

In the present paper, we describe cloning and expression of two outer membrane proteins, BpsOmp38 (from Burkholderia pseudomallei) and BthOmp38 (from Burkholderia thailandensis) lacking signal peptide sequences, using the pET23d(+) expression vector and Escherichia coli host strain Origami(DE3). The 38 kDa proteins, expressed as insoluble inclusion bodies, were purified, solubilized in 8 M urea, and then subjected to refolding experiments. As seen on SDS/PAGE, the 38 kDa band completely migrated to approximately 110 kDa when the purified monomeric proteins were refolded in a buffer system containing 10% (w/v) Zwittergent 3-14, together with a subsequent heating to 95 degrees C for 5 min. CD spectroscopy revealed that the 110 kDa proteins contained a predominant beta-sheet structure, which corresponded completely to the structure of the Omp38 proteins isolated from B. pseudomallei and B. thailandensis. Immunoblot analysis using anti-BpsOmp38 polyclonal antibodies and peptide mass analysis by MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS confirmed that the expressed proteins were BpsOmp38 and BthOmp38. The anti-BpsOmp38 antibodies considerably exhibited the inhibitory effects on the permeation of small sugars through the Omp38-reconstituted liposomes. A linear relation between relative permeability rates and M(r) of neutral sugars and charged antibiotics suggested strongly that the in vitro re-assembled Omp38 functioned fully as a diffusion porin.

An endochitinase A from Vibrio carchariae: cloning, expression, mass and sequence analyses, and chitin hydrolysis

We provide evidence that chitinase A from Vibrio carchariae acts as an endochitinase. The chitinase A gene isolated from V. carchariae genome encodes 850 amino acids expressing a 95-kDa precursor. Peptide masses of the native enzyme identified from MALDI-TOF or nanoESIMS were identical with the putative amino acid sequence translated from the corresponding nucleotide sequence. The enzyme has a highly conserved catalytic TIM-barrel region as previously described for Serratia marcescens ChiA. The Mr of the native chitinase A was determined to be 62,698, suggesting that the C-terminal proteolytic cleavage site was located between R597 and K598. The DNA fragment that encodes the processed enzyme was subsequently cloned and expressed in Escherichia coli. The expressed protein exhibited chitinase activity on gel activity assay. Analysis of chitin hydrolysis using HPLC/ESI-MS confirmed the endo characteristics of the enzyme.

Structure assignment, total synthesis, and evaluation of the phosphatase modulating activity of glucolipsin A

The previously unknown stereostructure of glucolipsin A (1), a complex glycolipid endowed with glucokinase-activating properties, was unambiguously elucidated as (2R,2'R,3S,3'S) by comparison of its spectroscopic and analytical data with those of all conceivable C(2)-symmetric stereoisomers. This set of macrodiolides was prepared by a sequence comprising auxiliary guided aldol reactions, glycosidation of the resulting beta-hydroxy acid derivatives with trichloroacetimidate 7, followed by hydrolytic cleavage of the auxiliaries used. The hydroxy acids thus formed were subjected to a macrodilactonization reaction mediated by 2-chloro-1,3-dimethylimidazolinium chloride (22) as the activating agent; this transformation is highly productive only in the presence of admixed potassium cations which likely serve as templates to preorganize two substrate molecules in a favorable head-to-tail arrangement. Glucolipsin and analogues were subjected to enzymatic assays that revealed that glycoconjugates of this type effectively inhibit the activity of the dual specific phosphatase Cdc25A with IC(50) values in the low micromolar range, while being hardly active against the tyrosine phosphatase PTP1B in vitro. This activity profile was compared to that of other glycolipids previously prepared in this laboratory, including cycloviracin B(1) (2), caloporoside (38), woodrosin I (39), sophorolipid lactone (40), and tricolorin G (41).

Functional reconstitution, gene isolation and topology modelling of porins from Burkholderia pseudomallei and Burkholderia thailandensis

The sequences for Omp38 from Burkholderia pseudomallei and Burkholderia thailandensis have been deposited in the DDBJ, EMBL, GenBank(R) and GSDB Nucleotide Sequence Databases under the accession numbers AY312416 and AY312417 respectively. The intracellular pathogen Burkholderia pseudomallei is the causative agent of tropical melioidosis, and Burkholderia thailandensis is a closely-related Gram-negative bacterium that does not cause serious disease. Like other bacteria, the major outer membrane (OM) porins of Burkholderia strains, Bps Omp38 and Bth Omp38 may have roles in antibiotic resistance and immunity. We purified both proteins and found them to be immunologically related, SDS-resistant, heat-sensitive trimers with M (r) of approx. 110000. In functional liposome-swelling assays, both proteins showed similar permeabilities for small sugar molecules, compatible with a pore diameter of between 1.2 and 1.6 nm. Secondary structure analysis by FTIR (Fourier-transform infrared) spectroscopy revealed almost identical spectra with predominantly beta-sheet structures, typical of bacterial porins. MALDI-TOF (matrix-assisted laser-desorption ionization-time of flight) MS and ESI/MS (electrospray ionization MS) analysis of each protein showed extensive sequence similarities to the OpcP1 porin from Burkholderia cepacia (later found to be 76.5% identical). Based on information from the incomplete B. pseudomallei genome-sequencing project, the genes encoding Omp38 were identified and amplified by PCR from B. pseudomallei and B. thailandensis genomic DNA. The nucleotide sequences are 99.7% identical, and the predicted processed proteins are 100% identical. Topology prediction and molecular modelling suggest that this newly-isolated and cloned porin is a 16-stranded beta-barrel and the external loops of the protein could be important determinants of the immune response to infection.

Molecular evolutionary convergence of the flight muscle protein arthrin in Diptera and hemiptera

Uniquely, the asynchronous flight muscle myofibrils of many insects contain arthrin, a stable 1:1 conjugate between actin and ubiquitin. The function of arthrin is still unknown. Here we survey for the presence of arthrin in 63 species of insect across nine orders using Western blotting. Analysis of the evolutionary distribution shows that arthrin has evolved a limited number of times but at least once in the Diptera and once in the Hemiptera. However, the presence of arthrin does not correlate with any observed common features of flight mechanism, natural history, or morphology. We also identify the site of the isopeptide bond in arthrin from Drosophila melanogaster (Diptera) and Lethocerus griseus (Hemiptera) using mass spectrometry. In both species, the isopeptide bond is formed between lysine 118 of the actin and the C-terminal glycine 76 of ubiquitin. Thus, not only the ubiquitination of actin but also the site of the isopeptide bond has evolved convergently in Diptera and Hemiptera. In terms of the actin monomer, lysine 118 is near neither the binding sites of the major actin-binding proteins, myosin, tropomyosin, or the troponins, nor the actin polymerization sites. However, molecular modeling supports the idea that ubiquitin bound to an actin in one F-actin strand might be able to interact with tropomyosin bound to the actin monomers of the other strand and thereby interfere with thin filament regulation.

Spontaneous rupture of the spleen: ultrasound patterns, diagnosis and follow-up

Spontaneous rupture of the spleen is an extremely rare complication usually of infectious diseases or disorders of the haematopoietic system and has been described mostly in case reports. The incidence, symptoms, causes, therapy, and prognosis are poorly defined. From July 1985 to January 2000 41 patients with spontaneous splenic rupture were diagnosed by abdominal ultrasound and confirmed by splenectomy (n=12), CT (n=15), and ultrasound follow up (n=26). An ultrasound grading system was retrospectively established based on the degree of splenic injury (grade 0-2=low grade injury, grade 3=high grade injury) and correlated with surgical procedures. 30 day mortality rate was studied in relation to underlying disorders, ultrasound grades and treatment decisions. 21 patients had underlying malignant disorders (group I) and 20 patients had benign diseases (group II). Between group I and II we observed a highly significant difference in 30 day mortality rates (n=7; 38.1% vs n=1; 5%, p<0.01), but no significant difference in high grade injury rate (n=3; 14.3% vs n=2; 10.0%; p=ns) and surgical treatment rate (n=5; 23.8% vs n=7; 35.0%; p=ns). Depending on ultrasound grades the surgical procedures were 0% for grade 0, 16.7% for grade 1, 30.4% for grade 2, and 60% for grade 3. There were no significant differences between patients, who died within the first 30 days (n=9) and those who survived more than 30 days (n=32) regarding high grade splenic injury rate (n=0; 0% vs n=5; 15.6%; p=ns), and surgical treatment rate (n=2; 22.2% vs n=10; 31.2%; p=ns). Spontaneous rupture of the spleen is an extremely rare event. It is associated with a high mortality rate within 30 days in patients with malignant disease. Sonomorphologic grading is helpful for treatment decisions. 30 day mortality rate is correlated with neither ultrasound grades, nor surgical treatment rates.

Synthesis, characterization, and application of cy-dye- and alexa-dye-labeled hongotoxin(1) analogues. The first high affinity fluorescence probes for voltage-gated K+ channels

Hongotoxin(1) (HgTX(1)), a 39-residue peptide recently isolated from the venom of Centruroides limbatus, blocks the voltage-gated K+ channels K(v)1.1, K(v)1.2, and K(v)1.3 at picomolar toxin concentrations (Koschak, A., Bugianesi, R. M., Mitterdorfer, J., Kaczorowski, G. J., Garcia, M. L., and Knaus, H. G. (1998) J. Biol. Chem. 273, 2639-2644). In this report, we determine the three-dimensional structure of HgTX(1) using NMR spectroscopy (PDB-code: 1HLY). HgTX(1) was found to possess a structure similar to previously characterized K+ channel toxins (e.g. margatoxin) consisting of a three-stranded antiparallel beta-sheet (residues 2-4, 26-30, and 33-37) and a helical conformation (part 3(10) helix and part alpha helix; residues 10-20). Due to the importance of residue Lys-28 for high-affinity interaction with the respective channels, lysine-reactive fluorescence dyes cannot be used to label wild-type HgTX(1). On the basis of previous studies (see above) and our NMR data, a HgTX(1) mutant (HgTX(1)-A19C) was engineered, expressed, and purified. HgTX(1)-A19C-SH was labeled using sulfhydryl-reactive Cy3-, Cy5-, and Alexa-dyes. Pharmacological characterization of fluorescently labeled HgTX(1)-A19C in radioligand binding studies indicated that these hongotoxin(1) analogues retain high-affinity for voltage-gated K+ channels and a respective pharmacological profile. Cy3- and Alexa-dye-labeled hongotoxin(1) analogues were used to investigate the localization of K+ channels in brain sections. The distribution of toxin binding closely follows the distribution of K(v)1.2 immunoreactivity with the highest expression levels in the cerebellar Purkinje cell layer. Taken together, these results demonstrate that fluorescently labeled HgTX(1) analogues comprise novel probes to characterize a subset of voltage-gated K+ channels.

Synthesis of nucleopeptides by employing an enzyme-labile urethane protecting group

Nucleoproteins are naturally occurring biopolymers in which the hydroxy group of a serine, a threonine, or a tyrosine moiety is linked through a phosphodiester group to the 3'- or 5'-end of a nucleic acid. For the study of the biological phenomena in which nucleoproteins are involved, for example, viral replication, nucleopeptides embodying the characteristic linkage between the peptide chain and the oligonucleotide may serve as powerful tools. However, as a result of the multifunctionality and the pronounced acid and base lability of nucleopeptides, their synthesis requires the application of a variety of orthogonally stable blocking groups, which can be removed under the mildest conditions. We have developed a new mild enzymatic deprotection method, that is, the penicillin G acylase-catalyzed hydrolysis of the N-phenylacetoxybenzyloxycarbony (PhAcOZ) group, for the synthesis of nucleopeptides. We demonstrate the wide applicability of this method by coupling the N-terminally deprotected nucleopeptides 31 a-c with PhAcOZ-protected amino acids and subsequent removal of the N-PhAcOZ group from fully protected nucleotetrapeptides 32 a,b with penicillin G acylase. The reaction conditions are very mild (pH 6.8) so that no undesired side reaction such as cleavage of the nucleotide bond or beta-elimination of the nucleotide was observed.

2-arylalkyl-substituted anthracenones as inhibitors of 12-lipoxygenase enzymes. 1. Structure-activity relationships of the terminal aryl ring

A series of 2-arylmethyl-substituted anthracenones were synthesized and tested as inhibitors of three types of 12-lipoxygenase isoforms in epidermal homogenate of mice, bovine platelets and porcine leucocytes. Their inhibitory activities were compared with those to inhibit the 5-lipoxygenase enzyme in bovine leucocytes. Structure-activity relationships are described with particular emphasis on modifications of the terminal aryl nucleus. The ability of the compounds to selectively inhibit the 12-lipoxygenase enzymes was dependent on a high overall lipophilicity of the inhibitor, whereas compounds with decreased lipophilicity were also inhibitors of the 5-LO enzyme. Among the more lipophilic inhibitors, the unsubstituted 2-phenylmethyl analogue 6a as well as the carboxylic acid ester 6q appeared to be selective inhibitors of platelet-type 12-LO isoform.

One hundred percent online identity check of pharmaceutical products by near-infrared spectroscopy on the packaging line

To increase product safety of pharmaceuticals, a new near-infrared (NIR) method for the online identity check of pharmaceutical finished products was validated. The method comprises a new near-infrared device VisioNIR (Uhlmann VisioTec GmbH, Laupheim, Germany) and the appropriate evaluation statistics. The VisioNIR is applied to the packaging line and provides the possibility to perform a 100% product identity check at full line speed. The products were analyzed applying near-infrared spectroscopy (900-1700 nm) in reflectance mode. The scanned products were two widely used pharmaceuticals named Capsule A (containing 300 mg of paracetamol and 250 mg of chlorzoxazone) and Capsule B (containing 500 mg of paracetamol and 30 mg of codeine phosphate). In order to demonstrate the fitness of the VisioNIR the obtained data were compared with the data acquired by Foss NIRSystems 6500 spectrometer (NIRSystems, Silver Springs, MD). The results obtained by the VisioNIR evaluation statistics were compared with the results obtained by the commonly used principal component analysis. The advantages and the suitability of the method are discussed. In this new configuration NIR spectroscopy offers an excellent possibility for non-destructive 100% online quality control of pharmaceutical products.

Influence of ABO blood groups on primary hemostasis

BACKGROUND

Recently, the in vitro bleeding time test (IVBT) was proved to be a very sensitive screening method for the detection of vWD, showing rather good correlation between the closure time and the level of vWF. The vWF levels have been found to be significantly lower in healthy humans who are group O than in those who belong to the other ABO blood groups (non-group O). The aim of this study was to detect whether these differences in vWF levels in normal persons correspond to differences in nonvascular primary hemostasis when investigated by the IVBT.

MATERIAL AND METHODS

Healthy blood donors (n = 162) without evidence of hemostatic disorders, without ingestion of drugs for at least 2 weeks, and with normal in vivo bleeding time endpoints, normal factor VIII clotting activity levels, normal structure of vWF multimers, and normal ristocetin-induced platelet aggregation were examined by IVBT. IVBT was performed with two automated systems (Thrombostat 4000, VDG [TST]; and a platelet function analyzer (PFA-100, Dade Behring [PFA]). CaCl2 and ADP were used as aggregants for the two TST tests (TST-CaCl2 and TST-ADP), and ADP- or epinephrine (Epi)-coated membranes were used with the two PFA tests (PFA-ADP and PFA-Epi).

RESULTS

Closure time in the IVBT significantly correlated with the blood groups, but in reverse order (as did blood volume; data not shown): TST-ADP (mean +/- SD): group O, 89 +/- 14.6 seconds versus non-group O, 82 +/- 13 seconds (p<0.01); TST-CaCl(2): group O, 154 +/- 28.9 seconds versus non-group O, 140 +/- 31.3 seconds (p<0.01); PFA-ADP: group O, 91 +/- 13.4 seconds versus non-group O, 86 +/- 11.9 seconds (p<0.05); PFA-Epi: group O, 112 +/- 15.4 seconds versus non-group O, 104 +/- 16.7 seconds (p<0.05). Donors with vWF < or =77.5 % had longer closure time than those with vWF >77.5 % (p<0.05).

CONCLUSION

Significant ABO-group-specific differences in nonvascular primary hemostasis could be found by IVBT. The differences are small, however, and lie within the normal range. Whether these differences have any biologic relevance can only be speculated.

Novel genes coding for lithotrophic sulfur oxidation of Paracoccus pantotrophus GB17

The gene region coding for lithotrophic sulfur oxidation of Paracoccus pantotrophus GB17 is located on a 13-kb insert of plasmid pEG12. Upstream of the previously described six open reading frames (ORFs) soxABCDEF with a partial sequence of soxA and soxF (C. Wodara, F. Bardischewsky, and C. G. Friedrich, J. Bacteriol. 179:5014-5023, 1997), 4,350 bp were sequenced. The sequence completed soxA, and uncovered six new ORFs upstream of soxA, designated ORF1, ORF2, and ORF3, and soxXYZ. ORF1 could encode a 275-amino-acid polypeptide of 29,332 Da with a 61 to 63% similarity to LysR transcriptional regulators. ORF2 could encode a 245-amino-acid polypeptide of 26,022 Da with the potential to form six transmembrane helices and with a 48 to 51% similarity to proteins involved in redox transport in cytochrome c biogenesis. ORF3 could encode a periplasmic polypeptide of 186 amino acids of 20,638 Da with a similarity to thioredoxin-like proteins and with a putative signal peptide of 21 amino acids. Purified SoxXA, SoxYZ, and SoxB are essential for thiosulfate or sulfite-dependent cytochrome c reduction in vitro. N-terminal and internal amino acid sequences identified SoxX, SoxY, SoxZ, and SoxA to be coded by the respective genes. The molecular masses of the mature proteins determined by electrospray ionization spectroscopy (SoxX, 14,834 Da; SoxY, 11,094 Da; SoxZ, 11,717 Da; and SoxA, 30,452 Da) were identical or close to those deduced from the nucleotide sequence with differences for the covalent heme moieties. SoxXA represents a novel type of periplasmic c-type cytochromes, with SoxX as a monoheme and SoxA as a hybrid diheme cytochrome c. SoxYZ is an as-yet-unprecedented soluble protein. SoxY has a putative signal peptide with a twin arginine motif and possibly cotransports SoxZ to the periplasm. SoxYZ neither contains a metal nor a complex redox center, as proposed for proteins likely to be transported via the Tat system.

[Design of a multicenter study for assessing the effectiveness of extracorporeal shockwave therapy in epicondylitis humeri radialis]

INTRODUCTION

Previously published studies concerning, extracorporeal shock-wave therapy (ESWT) in the treatment of lateral epicondylitis do not fulfil the biometric standards of modern clinical research. The objective of the trial is to show that ESWT is effective in the treatment of chronic LE.

METHOD

A prospective, randomized, placebo-controlled, single-blinded, multicenter trial with an independent blinded observer was designed. The effectiveness of ESWT is evaluated by comparison with a control group in which sham-ESWT is performed, both under local anaesthesia. Outcome is determined on the basis of the Roles/Maudsley-Score. Inclusion criteria are a history of at least 6 months of LE and failure of conventional treatment. The therapy includes 3 sessions of low energy ESWT with 2000 impulses (energy flux density 0.07-0.09 mJ/mm2). Sample size is 272 patients.

STATUS

Randomisation started in October 1998 and is planned over a period of two and a half years.

CONCLUSION

Only a randomised clinical trial with adequate control of placebo effects and observer bias can provide the required evidence for the efficiency of ESWT in the treatment of lateral epicondylitis of the elbow.

Drosophila ACT88F indirect flight muscle-specific actin is not N-terminally acetylated: a mutation in N-terminal processing affects actin function

Many eukaryotic proteins are co and post-translationally modified at their N termini by removal of one or two amino acid residues and N(alpha)-acetylation. Actins show two different forms of N-terminal processing dependent on their N-terminal sequence. In class II actins, which include muscle actins, the common primary sequence of Met-Cys-Asp-actin is processed to acetyl-Asp-actin. The functional significance of this in vivo is unknown. We have studied the indirect flight muscle-specific actin, ACT88F, of Drosophila melanogaster. Our results show that ACT88F is N-terminally processed in vivo as a class II actin by removal of the first two amino acid residues (Met and Cys), but that uniquely the N terminus is not acetylated. In addition we show that ACT88F is methylated, probably at His73. Flies carrying the mod(-) mutation fail to complete post-translational processing of ACT88F. We propose that the mod gene product is normally responsible for removing N-acetyl-cysteine from actin. The biological significance of this process is demonstrated by observations that retention of the N-acetyl-cysteine in ACT88F affects the flight muscle function of mod(-) flies. This suggests that the extreme N terminus affects actomyosin interactions in vivo, a proposal we have examined by in vitro motility assays of ACT88F F-actin from mod(-) flies. The mod(-) actin only moves in the presence of methylcellulose, a viscosity-enhancing agent, where it moves at velocities slightly, but significantly, reduced compared to wild-type. These data confirm that N-acetyl-cysteine at the N terminus affects actomyosin interactions, probably by reducing formation of the initial actomyosin collision complex, a process known to involve the actin N terminus.

Binding of nucleotides to guanylate kinase, p21(ras), and nucleoside-diphosphate kinase studied by nano-electrospray mass spectrometry

The binding of nucleotides to three different nucleotide-binding proteins and to a control protein was studied by means of nano-electrospray mass spectrometry applied to aqueous nondenaturing solutions. The method leads to unambiguous identification of enzyme complexes with substrates and products but does not allow the determination of dissociation constants or even stoichiometries relevant to the binding in solution. For guanylate kinase (EC 2.7.4. 8), the transfer of HPO(3) between nucleotides was observed whenever a ternary complex with adenylate or guanylate nucleotides was formed. Guanosine 5'-tetraphosphate was generated after prolonged incubation with GDP or GTP. Mg(2+) binding was considerably enhanced in functional high affinity complexes, such as observed between guanylate kinase and its bisubstrate inhibitor P(1)-(5'-guanosyl)-P(5)-(5'-adenosyl) pentaphosphate or with the tight nucleotide-binding protein p21(ras) and GDP. Nucleoside-diphosphate kinase (EC 2.7.4.6) itself was phosphorylated in accordance to its known ping-pong mechanism. All nucleotide-binding proteins were shown to bind sulfate (SO(4)(2-)) with presumably high affinity and slow exchange rate. The binding of phosphate (PO(4)(3-)) could be inferred indirectly from competition with SO(4)(2-).

The Ras mutant D119N is both dominant negative and activated

The introduction of mutation D119N (or its homolog) in the NKxD nucleotide binding motif of various Ras-like proteins produces constitutively activated or dominant-negative effects, depending on the system and assay. Here we show that Ras(D119N) has an inhibitory effect at a cell-specific concentration in PC12 and NIH 3T3 cells. Biochemical data strongly suggest that the predominant effect of mutation D119N in Ras-a strong decrease in nucleotide affinity-enables this mutant (i) to sequester its guanine nucleotide exchange factor, as well as (ii) to rapidly bind GTP, independent of the regulatory action of the exchange factor. Since mutation D119N does not affect the interaction between Ras and effector molecules, the latter effect causes Ras(D119N) to act as an activated Ras protein at concentrations higher than that of the exchange factor. In comparison, Ras(S17N), which also shows a strongly decreased nucleotide affinity, does not bind to effector molecules. These results point to two important prerequisites of dominant-negative Ras mutants: an increased relative affinity of the mutated Ras for the exchange factor over that for the nucleotide and an inability to interact with the effector or effectors. Remarkably, the introduction of a second, partial-loss-of-function, mutation turns Ras(D119N) into a strong dominant-negative mutant even at high concentrations, as demonstrated by the inhibitory effects of Ras(E37G/D119N) on nerve growth factor-mediated neurite outgrowth in PC12 cells and Ras(T35S/D119N) on fetal calf serum-mediated DNA synthesis in NIH 3T3 cells. Interpretations of these results are discussed.

cAPK-phosphorylation controls the interaction of the regulatory domain of cardiac myosin binding protein C with myosin-S2 in an on-off fashion

Myosin binding protein C is a protein of the myosin filaments of striated muscle which is expressed in isoforms specific for cardiac and skeletal muscle. The cardiac isoform is phosphorylated rapidly upon adrenergic stimulation of myocardium by cAMP-dependent protein kinase, and together with the phosphorylation of troponin-I and phospholamban contributes to the positive inotropy that results from adrenergic stimulation of the heart. Cardiac myosin binding protein C is phosphorylated by cAMP-dependent protein kinase on three sites in a myosin binding protein C specific N-terminal domain which binds to myosin-S2. This interaction with myosin close to the motor domain is likely to mediate the regulatory function of the protein. Cardiac myosin binding protein C is a common target gene of familial hypertrophic cardiomyopathy and most mutations encode N-terminal subfragments of myosin binding protein C. The understanding of the signalling interactions of the N-terminal region is therefore important for understanding the pathophysiology of myosin binding protein C associated cardiomyopathy. We demonstrate here by cosedimentation assays and isothermal titration calorimetry that the myosin-S2 binding properties of the myosin binding protein C motif are abolished by cAMP-dependent protein kinase-mediated tris-phosphorylation, decreasing the S2 affinity from a Kd of approximately 5 microM to undetectable levels. We show that the slow and fast skeletal muscle isoforms are no cAMP-dependent protein kinase substrates and that the S2 interaction of these myosin binding protein C isoforms is therefore constitutively on. The regulation of cardiac contractility by myosin binding protein C therefore appears to be a 'brake-off' mechanism that will free a specific subset of myosin heads from sterical constraints imposed by the binding to the myosin binding protein C motif.

[Intrarenal doppler flow analysis in patients with kidney transplantation and stable transplant function]

AIM OF THE STUDY

Intrarenal arterial Doppler sonography is used in noninvasive monitoring of transplant kidneys with controversial results. With the application of the method on renal transplants with stable function normal values should be generated and pitfalls should be identified. METHOD AND STUDY SUBJECTS: In a prospective study doppler findings in 61 renal transplant patients with stable graft function were compared with measurements in native kidneys of 60 healthy controls. In all kidneys duplex Doppler studies of arcuate/interlobar intrarenal arteries were performed and both the resistance index (RI) as well as the pulsatility index (PI) was determined.

RESULTS

The results of our study are summarized: 1. Transplanted kidneys have significantly higher intrarenal arterial flow indices in comparison to native kidneys: RI = 67 +/- 5% in allografts vs. RI = 57 +/- 5% in native kidneys; and PI = 123 +/- 21% in allografts vs. PI = 91 +/- 15% in native kidneys, respectively. 2. RI and PI increase with age in both the native kidneys and the allografts. However, the increase in the transplanted kidney correlates with the age of the recipient but not with the age of the donor. 3. Corresponding to the increase in RI and PI the blood pressure is significantly elevated in the elderly. 4. The degree of external pressure with the transducer on the graft has an impact on the intrarenal arterial Doppler findings and measurements obtained.

CONCLUSION

The intrarenal arterial Doppler findings dependent on various extrarenal factors. Using arterial Doppler sonography to evaluate transplant kidneys it is mandatory to take into account factors such as recipient's age and hemodynamic situation. External pressure with the transducer on the graft must be avoided. Once these factors were considered the intrarenal arterial Doppler sonography of kidney transplant is a valuable diagnostic tool.

Molecular basis of drug interaction with L-type Ca2+ channels

Different types of voltage-gated Ca2+ channels exist in the plasma membrane of electrically excitable cells. By controlling depolarization-induced Ca2+ entry into cells they serve important physiological functions, such as excitation-contraction coupling, neurotransmitter and hormone secretion, and neuronal plasticity. Their function is fine-tuned by a variety of modulators, such as enzymes and G-proteins. Block of so-called L-type Ca2+ channels by drugs is exploited as a therapeutic principle to treat cardiovascular disorders, such as hypertension. More recently, block of so-called non-L-type Ca2+ channels was found to exert therapeutic effects in the treatment of severe pain and ischemic stroke. As the subunits of different Ca2+ channel types have been cloned, the modulatory sites for enzymes, G-proteins, and drugs can now be determined using molecular engineering and heterologous expression. Here we summarize recent work that has allowed us to determine the sites of action of L-type Ca2+ channel modulators. Together with previous biochemical, electrophysiological, and drug binding data these results provide exciting insight into the molecular pharmacology of this voltage-gated Ca2+ channel family.

Kinetic analysis by fluorescence of the interaction between Ras and the catalytic domain of the guanine nucleotide exchange factor Cdc25Mm

Guanine nucleotide exchange factors (GEFs) activate Ras proteins by stimulating the exchange of GTP for GDP in a multistep mechanism which involves binary and ternary complexes between Ras, guanine nucleotide, and GEF. We present fluorescence measurements to define the kinetic constants that characterize the interactions between Ras, GEF, and nucleotides, similar to the characterization of the action of RCC1 on Ran [Klebe et al. (1995) Biochemistry 34, 12543-12552]. The dissociation constant for the binary complex between nucleotide-free Ras and the catalytic domain of mouse Cdc25, Cdc25(Mm285), was 4.6 nM, i.e., a 500-fold lower affinity than the Ras.GDP interaction. The affinities defining the ternary complex Ras. nucleotide.Cdc25(Mm285) are several orders of magnitude lower. The maximum acceleration by Cdc25(Mm285) of the GDP dissociation from Ras was more than 10(5)-fold. Kinetic measurements of the association of nucleotide to nucleotide-free Ras and to the binary complex Ras. Cdc25(Mm285) show that these reactions are practically identical: a fast binding step is followed by a reaction of the first order which becomes rate limiting at high nucleotide concentrations. The second reaction is thought to be a conformational change from a low- to a high-affinity nucleotide binding conformation in Ras. Taking into consideration all experimental data, the reverse isomerization reaction from a high- to a low-affinity binding conformation in the ternary complex Ras. GDP.Cdc25(Mm285) is postulated to be the rate-limiting step of the GEF-catalyzed exchange. Furthermore, we demonstrate that the disruption of the Mg2+-binding site is not the only factor in the mechanism of GEF-catalyzed nucleotide exchange on Ras.

Simple analogues of anthralin: unusual specificity of structure and antiproliferative activity

Fifty-nine simple analogues of the antipsoriatic agent, anthralin, have been prepared by modifying the positions of the 1,8-hydroxyl groups, replacement of the hydroxyl groups, substitution at the oxygen functions, introduction of additional functional groups into various positions of the anthracenone nucleus, or removal of particular structural elements. The compounds were evaluated for their antiproliferative action against human keratinocytes and inhibition of the generation of leukotriene B4 in polymorphonuclear leukocytes, which may be useful to resolve the proliferative and inflammatory aspects of psoriasis, respectively. Even though many anthracenones were more potent inhibitors of leukotriene biosynthesis than anthralin, none of the compounds was substantially more effective as this drug in suppressing keratinocyte cell growth. There is an absolute requirement for two hydroxyl groups peri to a hydrogen bond acceptor such as a keto or an imino group for high potency. In addition to further delineating the nature of the pharmacophore for this class of compounds, also naphthalenedione with a peri hydroxyl group was identified as a pharmacophore with antiproliferative activity against keratinocyte growth.