Automated multi-attribute method sample preparation using high-throughput buffer exchange tips

RATIONALE

The multi-attribute method (MAM) has become a valuable mass spectrometry (MS)-based tool that can identify and quantify the site-specific product attributes and purity information for biotherapeutics such as monoclonal antibodies (mAbs) and fusion molecules in recent years. As we expand the use of the MAM at various stages of drug development, it is critical to enhance the sample preparation throughput without additional chemical modifications and variability.

METHODS

In this study, a fully automated MAM sample preparation protocol is presented, where rapid desalting in less than 15 minutes is achieved using miniaturized size-exclusion chromatography columns in pipette tips on an automated liquid handler. The peptide samples were analyzed using an electrospray ionization (ESI) orbitrap mass spectrometer coupled to an ultra-high-performance liquid chromatography (UHPLC) system with a dual column switching system.

RESULTS

No significant change was observed in product attributes and their quantities compared with manual, low-artifact sample preparation. The sample recovery using the buffer exchange tips was greatly enhanced over the manual spin cartridges while still demonstrating excellent reproducibility for a wide variety of starting sample concentrations. Unlike a plate desalting system, the individual columns provide flexibility in the number of samples prepared at a time and sample locations within plates.

CONCLUSIONS

This automated protocol enables the preparation of up to 96 samples with less "at-bench" time than the manual preparation of a smaller batch of samples, thereby greatly facilitating support of process development and the use of the MAM in quality control.

Evaluation of Crystal Zenith Microtiter Plates for High-Throughput Formulation Screening

Formulation screening for biotherapeutics can cover a vast array of excipients and stress conditions. These studies consume quantities of limited material and, with higher concentrated therapeutics, more material is needed. Here, we evaluate the use of crystal zenith (CZ) microtiter plates in conjunction with FluoroTec-coated butyl rubber mats as a small-volume, high-throughput system for formulation stability studies. The system was studied for evaporation, edge effects, and stability with comparisons to type 1 glass and CZ vials for multiple antibodies and formulations. Evaporation was minimal at 4°C and could be reduced at elevated temperatures using sealed, mylar bags. Edge effects were not observed until 12 weeks at 40°C. The overall stability ranking as measured by the rate of change in high molecular weight and percent main peak species was comparable across both vials and plates at 4°C and 40°C out to 12 weeks. Product quality attributes as measured by the multi-attribute method were also comparable across all containers for each molecule formulation. A potential difference was measured for subvisible particle analysis, with the plates measuring lower particle counts than the vials. Overall, CZ plates are a viable alternative to traditional vials for small-volume, high-throughput formulation stability screening studies.

Coformulation of Broadly Neutralizing Antibodies 3BNC117 and PGT121: Analytical Challenges During Preformulation Characterization and Storage Stability Studies

In this study, we investigated analytical challenges associated with the formulation of 2 anti-HIV broadly neutralizing antibodies (bnAbs), 3BNC117 and PGT121, both separately at 100 mg/mL and together at 50 mg/mL each. The bnAb formulations were characterized for relative solubility and conformational stability followed by accelerated and real-time stability studies. Although the bnAbs were stable during 4°C storage, incubation at 40°C differentiated their stability profiles. Specific concentration-dependent aggregation rates at 30°C and 40°C were measured by size exclusion chromatography for the individual bnAbs with the mixture showing intermediate behavior. Interestingly, although the relative ratio of the 2 bnAbs remained constant at 4°C, the ratio of 3BNC117 to PGT121 increased in the dimer that formed during storage at 40°C. A mass spectrometry-based multiattribute method, identified and quantified differences in modifications of the Fab regions for each bnAb within the mixture including clipping, oxidation, deamidation, and isomerization sites. Each bnAb showed slight differences in the levels and sites of lysine residue glycations. Together, these data demonstrate the ability to differentiate degradation products from individual antibodies within the bnAb mixture, and that degradation rates are influenced not only by the individual bnAb concentrations but also by the mixture concentration.

CHO cell production and sequence improvement in the 13C6FR1 anti-Ebola antibody

From March 2014 through February 2015, the Ebola virus spread rapidly in West Africa, resulting in almost 30,000 infections and approximately 10,000 deaths. With no approved therapeutic options available, an experimental antibody cocktail known as ZMapp™ was administered to patients on a limited compassionate-use basis. The supply of ZMapp™ was highly constrained at the time because it was in preclinical development and a novel production system (tobacco plants) was being used for manufacturing. To increase the production of ZMapp™ for an uncertain future demand, a consortium was formed in the fall of 2014 to quickly manufacture these anti-Ebola antibodies in Chinese hamster ovary (CHO) cells using bioreactors for production at a scale appropriate for thousands of doses. As a result of the efforts of this consortium, valuable lessons were learned about the processing of the antibodies in a CHO-based system. One of the ZMapp™ cocktail antibodies, known as c13C6FR1, had been sequence-optimized in the framework region for production in tobacco and engineered as a chimeric antibody. When transfected into CHO cells with the unaltered sequence, 13C6FR1 was difficult to process. This report describes efforts to produce 13C6FR1 and the parental murine hybridoma sequence, 13C6mu, in CHO cells, and provides evidence for the insertion of a highly conserved framework amino acid that improved the physical properties necessary for high-level expression and purification. Furthermore, it describes the technical and logistical lessons learned that may be beneficial in the event of a future Ebola virus or other pandemic viral outbreaks where mAbs are considered potential therapeutics.

Peroxins Pex30 and Pex29 Dynamically Associate with Reticulons to Regulate Peroxisome Biogenesis from the Endoplasmic Reticulum

Peroxisome proliferation occurs by at least two routes, division of existing peroxisomes and de novo biogenesis from the endoplasmic reticulum (ER). The proteins and molecular mechanisms governing peroxisome emergence from the ER are poorly characterized. In this study, we report that two integral membrane peroxins (proteins required for peroxisome biogenesis) in Saccharomyces cerevisiae, Pex29 and Pex30, reside in distinct regions of the ER and associate with Rtn1 and Yop1, reticulon family members that contribute to ER morphology, to govern peroxisome emergence from the ER. In vivo and in vitro analyses reveal that peroxisome proliferation is therefore not restricted to the peroxisome but begins at the level of the ER.

Development of a quantitative mass spectrometry multi-attribute method for characterization, quality control testing and disposition of biologics

Regulatory agencies have recently recommended a Quality by Design (QbD) approach for the manufacturing of therapeutic molecules. A QbD strategy requires deep understanding at the molecular level of the attributes that are crucial for safety and efficacy and for insuring that the desired quality of the purified protein drug product is met at the end of the manufacturing process. A mass spectrometry (MS)-based approach to simultaneously monitor the extensive array of product quality attributes (PQAs) present on therapeutic molecules has been developed. This multi-attribute method (MAM) uses a combination of high mass accuracy / high resolution MS data generated by Orbitrap technology and automated identification and relative quantification of PQAs with dedicated software (Pinpoint). The MAM has the potential to replace several conventional electrophoretic and chromatographic methods currently used in Quality Control to release therapeutic molecules. The MAM represents an optimized analytical solution to focus on the attributes of the therapeutic molecule essential for function and implement QbD principles across process development, manufacturing and drug disposition.

Quantitative proteomic analysis of host-virus interactions reveals a role for Golgi brefeldin A resistance factor 1 (GBF1) in dengue infection

Dengue virus is considered to be the most important mosquito-borne virus worldwide and poses formidable economic and health care burdens on many tropical and subtropical countries. Dengue infection induces drastic rearrangement of host endoplasmic reticulum membranes into complex membranous structures housing replication complexes; the contribution(s) of host proteins and pathways to this process is poorly understood but is likely to be mediated by protein-protein interactions. We have developed an approach for obtaining high confidence protein-protein interaction data by employing affinity tags and quantitative proteomics, in the context of viral infection, followed by robust statistical analysis. Using this approach, we identified high confidence interactors of NS5, the viral polymerase, and NS3, the helicase/protease. Quantitative proteomics allowed us to exclude a large number of presumably nonspecific interactors from our data sets and imparted a high level of confidence to our resulting data sets. We identified 53 host proteins reproducibly associated with NS5 and 41 with NS3, with 13 of these candidates present in both data sets. The host factors identified have diverse functions, including retrograde Golgi-to-endoplasmic reticulum transport, biosynthesis of long-chain fatty-acyl-coenzyme As, and in the unfolded protein response. We selected GBF1, a guanine nucleotide exchange factor responsible for ARF activation, from the NS5 data set for follow up and functional validation. We show that GBF1 plays a critical role early in dengue infection that is independent of its role in the maintenance of Golgi structure. Importantly, the approach described here can be applied to virtually any organism/system as a tool for better understanding its molecular interactions.

Independent and epistatic effects of variants in VPS10-d receptors on Alzheimer disease risk and processing of the amyloid precursor protein (APP)

Genetic variants in the sortilin-related receptor (SORL1) and the sortilin-related vacuolar protein sorting 10 (VPS10) domain-containing receptor 1 (SORCS1) are associated with increased risk of Alzheimer's disease (AD), declining cognitive function and altered amyloid precursor protein (APP) processing. We explored whether other members of the (VPS10) domain-containing receptor protein family (the sortilin-related VPS10 domain-containing receptors 2 and 3 (SORCS2 and SORCS3) and sortilin (SORT1)) would have similar effects either independently or together. We conducted the analyses in a large Caucasian case control data set (n=11,840 cases, 10,931 controls) to determine the associations between single nucleotide polymorphisms (SNPs) in all the five homologous genes and AD risk. Evidence for interactions between SNPs in the five VPS10 domain receptor family genes was determined in epistatic statistical models. We also compared expression levels of SORCS2, SORCS3 and SORT1 in AD and control brains using microarray gene expression analyses and assessed the effects of these genes on γ-secretase processing of APP. Several SNPs in SORL1, SORCS1, SORCS2 and SORCS3 were associated with AD. In addition, four specific linkage disequilibrium blocks in SORCS1, SORCS2 and SORCS3 showed additive epistatic effects on the risk of AD (P≤0.0006). SORCS3, but not SORCS2 or SORT1, showed reduced expression in AD compared with control brains, but knockdown of all the three genes using short hairpin RNAs in HEK293 cells caused a significant threefold increase in APP processing (from P<0.001 to P<0.05). These findings indicate that in addition to SORL1 and SORCS1, variants in other members of the VPS10 domain receptor family (that is, SORCS1, SORCS2, SORCS3) are associated with AD risk and alter APP processing. More importantly, the results indicate that variants within these genes have epistatic effects on AD risk.

Urban legends: recurrent aphthous stomatitis

Recurrent aphthous stomatitis (RAS) is the most common idiopathic intraoral ulcerative disease in the USA. Aphthae typically occur in apparently healthy individuals, although an association with certain systemic diseases has been reported. Despite the unclear etiopathogenesis, new drug trials are continuously conducted in an attempt to reduce pain and dysfunction. We investigated four controversial topics: (1) Is complex aphthosis a mild form of Behçet's disease (BD)? (2) Is periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome a distinct medical entity? (3) Is RAS associated with other systemic diseases [e.g., celiac disease (CD) and B12 deficiency]? (4) Are there any new RAS treatments? Results from extensive literature searches, including a systematic review of RAS trials, suggested the following: (1) Complex aphthosis is not a mild form of BD in North America or Western Europe; (2) Diagnostic criteria for PFAPA have low specificity and the characteristics of the oral ulcers warrant further studies; (3) Oral ulcers may be associated with CD; however, these ulcers may not be RAS; RAS is rarely associated with B12 deficiency; nevertheless, B12 treatment may be beneficial, via mechanisms that warrant further study; (4) Thirty-three controlled trials published in the past 6 years reported some effectiveness, although potential for bias was high.

Urban legends: recurrent aphthous stomatitis

Recurrent aphthous stomatitis (RAS) is the most common idiopathic intraoral ulcerative disease in the USA. Aphthae typically occur in apparently healthy individuals, although an association with certain systemic diseases has been reported. Despite the unclear etiopathogenesis, new drug trials are continuously conducted in an attempt to reduce pain and dysfunction. We investigated four controversial topics: (1) Is complex aphthosis a mild form of Behçet's disease (BD)? (2) Is periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome a distinct medical entity? (3) Is RAS associated with other systemic diseases [e.g., celiac disease (CD) and B12 deficiency]? (4) Are there any new RAS treatments? Results from extensive literature searches, including a systematic review of RAS trials, suggested the following: (1) Complex aphthosis is not a mild form of BD in North America or Western Europe; (2) Diagnostic criteria for PFAPA have low specificity and the characteristics of the oral ulcers warrant further studies; (3) Oral ulcers may be associated with CD; however, these ulcers may not be RAS; RAS is rarely associated with B12 deficiency; nevertheless, B12 treatment may be beneficial, via mechanisms that warrant further study; (4) Thirty-three controlled trials published in the past 6 years reported some effectiveness, although potential for bias was high.

Characterizing the connectivity of poly-ubiquitin chains by selected reaction monitoring mass spectrometry

Protein ubiquitination is an essential post-translational modification (PTM) involved in the regulation of a variety of cellular functions, including transcription and protein degradation. Proteins can be both mono- or poly-ubiquitinated. Poly-ubiquitin chains vary in the manner by which the ubiquitin proteins are linked and their total length. Different poly-ubiquitin structures are thought to specify different fates for the target protein but the correlation between poly-ubiquitin structures and their specific cellular function(s) is not well understood. We have developed a set of specific and quantitative targeted mass spectrometry assays to determine the frequency of different types of inter-ubiquitin linkages in poly-ubiquitin chains relative to the total ubiquitin concentration. We chemically synthesized heavy isotope labeled reference peptides that represent the products generated by tryptic digestion of the known forms of inter-ubiquitin links for the yeast Saccharomyces cerevisiae and human, in addition to all peptides from tryptic digestion of a single ubiquitin molecule for these two species. We used these peptides to develop optimized Selected Reaction Monitoring (SRM) assays for their unambiguous detection in biological samples. We used these assays to profile the frequency of the different types of inter-ubiquitin linkages in a mixture of in vitro assembled human poly-ubiquitin chains and 15 isolated poly-ubiquitinated proteins from S. cerevisiae. We then applied the method to detect toxin induced changes in the poly-ubiquitination profile in complex and enriched protein samples.

QTIPS: a novel method of unsupervised determination of isotopic amino acid distribution in SILAC experiments

Stable incorporation of labeled amino acids in cell culture is a simple approach to label proteins in vivo for mass spectrometric quantification. Full incorporation of isotopically heavy amino acids facilitates accurate quantification of proteins from different cultures, yet analysis methods for determination of incorporation are cumbersome and time-consuming. We present QTIPS, Quantification by Total Identified Peptides for SILAC, a straightforward, accurate method to determine the level of heavy amino acid incorporation throughout a population of peptides detected by mass spectrometry. Using QTIPS, we show that the incorporation of heavy amino acids in baker's yeast is unaffected by the use of prototrophic strains, indicating that auxotrophy is not a requirement for SILAC experiments in this organism. This method has general utility for multiple applications where isotopic labeling is used for quantification in mass spectrometry.

Integrated phosphoproteomics analysis of a signaling network governing nutrient response and peroxisome induction

Phosphorylation of proteins is a key posttranslational modification in cellular signaling, regulating many aspects of cellular responses. We used a quantitative, integrated, phosphoproteomics approach to characterize the cellular responses of the yeast Saccharomyces cerevisiae to the fatty acid oleic acid, a molecule with broad human health implications and a potent inducer of peroxisomes. A combination of cryolysis and urea solubilization was used to minimize the opportunity for reorientation of the phosphoproteome, and hydrophilic interaction liquid chromatography and IMAC chemistries were used to fractionate and enrich for phosphopeptides. Using these approaches, numerous phosphorylated peptides specific to oleate-induced and glucose-repressed conditions were identified and mapped to known signaling pathways. These include several transcription factors, two of which, Pip2p and Cst6p, must be phosphorylated for the normal transcriptional response of fatty acid-responsive loci encoding peroxisomal proteins. The phosphoproteome data were integrated with results from genome-wide assays studying the effects of signaling molecule deletions and known protein-protein interactions to generate a putative fatty acid-responsive signaling network. In this network, the most highly connected nodes are those with the largest effects on cellular responses to oleic acid. These properties are consistent with a scale-free topology, demonstrating that scale-free properties are conserved in condition-specific networks.

GINS motion reveals replication fork progression is remarkably uniform throughout the yeast genome

Time-resolved ChIP-chip can be utilized to monitor the genome-wide dynamics of the GINS complex, yielding quantitative information on replication fork movement.

Replication forks progress at remarkably uniform rates across the genome, regardless of location.

GINS progression appears to be arrested, albeit with very low frequency, at sites of highly transcribed genes.

Comparison of simulation with data leads to novel biological insights regarding the dynamics of replication fork progression

In mitotic division, cells duplicate their DNA in S phase to ensure that the proper genetic material is passed on to their progeny. This process of DNA replication is initiated from several hundred specific sites, termed origins of replication, spaced across the genome. It is essential for replication to begin only after G₁ and finish before the initiation of anaphase (Blow and Dutta, 2005; Machida et al, 2005). To ensure proper timing, the beginning stages of DNA replication are tightly coupled to the cell cycle through the activity of cyclin-dependent kinases (Nguyen et al, 2001; Masumoto et al, 2002; Sclafani and Holzen, 2007), which promote the accumulation of the pre-RC at the origins and initiate replication. Replication fork movement occurs subsequent to the firing of origins on recruitment of the replicative helicase and the other fork-associated proteins as the cell enters S phase (Diffley, 2004). The replication machinery itself (polymerases, PCNA, etc.) trails behind the helicase, copying the newly unwound DNA in the wake of the replication fork.

One component of the pre-RC, the GINS complex, consists of a highly conserved set of paralogous proteins (Psf1, Psf2, Psf3 and Sld5 (Kanemaki et al, 2003; Kubota et al, 2003; Takayama et al, 2003)). Previous work suggests that the GINS complex is an integral component of the replication fork and that its interaction with the genome correlates directly to the movement of the fork (reviewed in Labib and Gambus, 2007). Here, we used the GINS complex as a surrogate to measure features of the dynamics of replication—that is, to determine which origins in the genome are active, the timing of their firing and the rates of replication fork progression.

The timing of origin firing and the rates of fork progression have also been investigated by monitoring nascent DNA synthesis (Raghuraman et al, 2001; Yabuki et al, 2002). Origin firing was observed to occur as early as 14 min into the cell cycle and as late as 44 min (Raghuraman et al, 2001). A wide range of nucleotide incorporation rates (0.5–11 kb/min) were observed, with a mean of 2.9 kb/min (Raghuraman et al, 2001), whereas a second study reported a comparable mean rate of DNA duplication of 2.8±1.0 kb/min (Yabuki et al, 2002). In addition to these observations, replication has been inferred to progress asymmetrically from certain origins (Raghuraman et al, 2001). These data have been interpreted to mean that the dynamics of replication fork progression are strongly affected by local chromatin structure or architecture, and perhaps by interaction with the machineries controlling transcription, repair and epigenetic maintenance (Deshpande and Newlon, 1996; Rothstein et al, 2000; Raghuraman et al, 2001; Ivessa et al, 2003). In this study, we adopted a complementary ChIP-chip approach for assaying replication dynamics, in which we followed GINS complexes as they traverse the genome during the cell cycle (Figure 1). These data reveal that GINS binds to active replication origins and spreads bi-directionally and symmetrically as S phase progresses (Figure 3). The majority of origins appear to fire in the first ∼15 min of S phase. A small fraction (∼10%) of the origins to which GINS binds show no evidence of spreading (category 3 origins), although it remains possible that these peaks represent passively fired origins (Shirahige et al, 1998). Once an active origin fires, the GINS complex moves at an almost constant rate of 1.6±0.3 kb/min. Its movement through the inter-origin regions is consistent with that of a protein complex associated with a smoothly moving replication fork. This progression rate is considerably lower and more tightly distributed than those inferred from previous genome-wide measurements assayed through nascent DNA production (Raghuraman et al, 2001; Yabuki et al, 2002). Our study leads us to a different view of replication fork dynamics wherein fork progression is highly uniform in rate and little affected by genomic location.

In this work, we also observe a large number of low-intensity persistent features at sites of high transcriptional activity (e.g. tRNA genes). We were able to accurately simulate these features by assuming they are the result of low probability arrest of replication forks at these sites, rather than fork pausing (Deshpande and Newlon, 1996). The extremely low frequency of these events in wild-type cells suggests they are due to low probability stochastic occurrences during the replication process. It is hoped that future studies will resolve whether these persistent features indeed represent rare instances of fork arrest, or are the result of some alternative process. These may include, for example, the deposition of GINS complexes (or perhaps more specifically Psf2) once a pause has been resolved.

In this work, we have made extensive use of modeling to test a number of different hypotheses and assumptions. In particular, iterative modeling allowed us to infer that GINS progression is uniform and smooth throughout the genome. We have also demonstrated the potential of simulations for estimating firing efficiencies. In the future, extending such firing efficiency simulations to the whole genome should allow us to make correlations with chromosomal features such as nucleosome occupancy. Such correlations may help in determining factors that govern the probability of replication initiation throughout the genome.

Previous studies have led to a picture wherein the replication of DNA progresses at variable rates over different parts of the budding yeast genome. These prior experiments, focused on production of nascent DNA, have been interpreted to imply that the dynamics of replication fork progression are strongly affected by local chromatin structure/architecture, and by interaction with machineries controlling transcription, repair and epigenetic maintenance. Here, we adopted a complementary approach for assaying replication dynamics using whole genome time-resolved chromatin immunoprecipitation combined with microarray analysis of the GINS complex, an integral member of the replication fork. Surprisingly, our data show that this complex progresses at highly uniform rates regardless of genomic location, revealing that replication fork dynamics in yeast is simpler and more uniform than previously envisaged. In addition, we show how the synergistic use of experiment and modeling leads to novel biological insights. In particular, a parsimonious model allowed us to accurately simulate fork movement throughout the genome and also revealed a subtle phenomenon, which we interpret as arising from low-frequency fork arrest.

A role for the karyopherin Kap123p in microtubule stability

Several components of the nuclear transport machinery play a role in mitotic spindle assembly in higher eukaryotes. To further investigate the role of this family of proteins in microtubule function, we screened for mutations in Saccharomyces cerevisiae that confer sensitivity to microtubule-destabilizing drugs. One mutant exhibiting this phenotype lacked the gene encoding the karyopherin Kap123p. Analysis of kap123Delta cells revealed that the drug sensitivity was caused by a defect in microtubule stability and/or assembly. In support of this idea, we demonstrated genetic interactions between the kap123Delta mutation and mutated alleles of genes encoding alpha-tubulins and factors controlling microtubule dynamics. Moreover, kap123Delta cells exhibit defects in spindle structure and dynamics as well as nuclear positioning defects during mitosis. Cultures of kap123Delta strains are enriched for mononucleated large-budded cells often containing short spindles and nuclei positioned away from the budneck, phenotypes indicative of defects in both cytoplasmic and nuclear microtubules. Finally, we identified a gene, CAJ1, which when deleted in combination with KAP123 exacerbated the microtubule-related defects of the kap123Delta mutants. We propose that Kap123p and Caj1p, a member of the Hsp40 family of proteins, together play an essential role in normal microtubule function.

Yng1 PHD finger binding to H3 trimethylated at K4 promotes NuA3 HAT activity at K14 of H3 and transcription at a subset of targeted ORFs

Posttranslational histone modifications participate in modulating the structure and function of chromatin. Promoters of transcribed genes are enriched with K4 trimethylation and hyperacetylation on the N-terminal tail of histone H3. Recently, PHD finger proteins, like Yng1 in the NuA3 HAT complex, were shown to interact with H3K4me3, indicating a biochemical link between K4 methylation and hyperacetylation. By using a combination of mass spectrometry, biochemistry, and NMR, we detail the Yng1 PHD-H3K4me3 interaction and the importance of NuA3-dependent acetylation at K14. Furthermore, genome-wide ChIP-Chip analysis demonstrates colocalization of Yng1 and H3K4me3 in vivo. Disrupting the K4me3 binding of Yng1 altered K14ac and transcription at certain genes, thereby demonstrating direct in vivo evidence of sequential trimethyl binding, acetyltransferase activity, and gene regulation by NuA3. Our data support a general mechanism of transcriptional control through which histone acetylation upstream of gene activation is promoted partially through availability of H3K4me3, "read" by binding modules in select subunits.

Cutaneous Crohn's disease mimicking Melkersson-Rosenthal syndrome: treatment with methotrexate

A woman with a 5-year history of unilateral orofacial granulomatosis required repeated evaluations (including sequential colonoscopies) to establish the diagnosis of cutaneous Crohn's disease, a condition that proved responsive to low doses of oral methotrexate administered weekly. To our knowledge this is the first report describing the use of methotrexate for treatment of orofacial granulomatosis caused by underlying Crohn's disease.

The mobile nucleoporin Nup2p and chromatin-bound Prp20p function in endogenous NPC-mediated transcriptional control

Nuclear pore complexes (NPCs) govern macromolecular transport between the nucleus and cytoplasm and serve as key positional markers within the nucleus. Several protein components of yeast NPCs have been implicated in the epigenetic control of gene expression. Among these, Nup2p is unique as it transiently associates with NPCs and, when artificially tethered to DNA, can prevent the spread of transcriptional activation or repression between flanking genes, a function termed boundary activity. To understand this function of Nup2p, we investigated the interactions of Nup2p with other proteins and with DNA using immunopurifications coupled with mass spectrometry and microarray analyses. These data combined with functional assays of boundary activity and epigenetic variegation suggest that Nup2p and the Ran guanylyl-nucleotide exchange factor, Prp20p, interact at specific chromatin regions and enable the NPC to play an active role in chromatin organization by facilitating the transition of chromatin between activity states.

Oral ulcerations are associated with the loss of response to infliximab in Crohn's disease

We describe a 25-year-old Caucasian man with a 13-year history of inflammatory Crohn's disease (CD) who was suffering recurrent severe oral and esophageal ulcerations for the past 3 years. His CD had been treated with infliximab infusions among other medications. The loss of efficacy was confirmed by antibodies to infliximab (ATI) and serum infliximab tests that showed high levels of ATIs and undetectable levels of infliximab respectively. These findings were consistent with significant immunogenic response to infliximab leading to loss of effect. Infliximab infusions and prednisone were discontinued and treatment of the CD was instituted with adalimumab, a human anti-tumor necrosis factor (TNF)-alpha biologic agent, to control the inflammatory small intestinal disease and dapsone for the oral and esophageal CD ulcerations. The patient's oral and esophageal lesions as well as the enteric CD are under control after 5 months of therapy.

SUMO modified proteins localize to the XY body of pachytene spermatocytes

The XY body is a specialized chromatin territory that forms during meiotic prophase of spermatogenesis and comprises the transcriptionally repressed sex chromosomes. Remodeling of the XY chromatin is brought about by recruitment of specific proteins to the X and Y chromosomes during meiosis, and also by post-translational modifications of histones and other chromatin-associated proteins. Here, we demonstrate that SUMO, a small ubiquitin-related modifier protein that regulates a wide variety of nuclear functions in somatic cells, dramatically localizes to the XY body. SUMO was first detected in the XY body of early pachytene spermatocytes and gradually accumulated, reaching maximal levels there during the mid to late pachytene stages. Several known SUMO substrates, including PML and DAXX, were also found to accumulate in the XY body of mid to late stage pachytene spermatocytes. These same proteins localize to PML nuclear bodies of somatic interphase nuclei. Together, these findings indicate a role for SUMO modification in regulating the structure and function of the XY body and reveal molecular similarities between the XY body and PML nuclear bodies.

A conserved catalytic residue in the ubiquitin-conjugating enzyme family

Ubiquitin (Ub) regulates diverse functions in eukaryotes through its attachment to other proteins. The defining step in this protein modification pathway is the attack of a substrate lysine residue on Ub bound through its C-terminus to the active site cysteine residue of a Ub-conjugating enzyme (E2) or certain Ub ligases (E3s). So far, these E2 and E3 cysteine residues are the only enzyme groups known to participate in the catalysis of conjugation. Here we show that a strictly conserved E2 asparagine residue is critical for catalysis of E2- and E2/RING E3-dependent isopeptide bond formation, but dispensable for upstream and downstream reactions of Ub thiol ester formation. In contrast, the strictly conserved histidine and proline residues immediately upstream of the asparagine are dispensable for catalysis of isopeptide bond formation. We propose that the conserved asparagine side chain stabilizes the oxyanion intermediate formed during lysine attack. The E2 asparagine is the first non-covalent catalytic group to be proposed in any Ub conjugation factor.

SUMO modification of STAT1 and its role in PIAS-mediated inhibition of gene activation

The PIAS (protein inhibitors of activated STAT) family of proteins were first discovered as inhibitors of activated signal transducers and activators of transcription (STATs). More recently these proteins have been shown to function as E3 ligases that promote the SUMO modification of a number of transcription regulators. We have investigated the relationship between the effects of PIAS proteins on STAT1 transcriptional activity and the ability of the PIAS proteins to function as SUMO E3 ligases. We demonstrate that STAT1 is a substrate for SUMO modification and that PIASx-alpha, but not PIAS1, functions as an E3 ligase to promote STAT1 modification. In addition, we have mapped the major site for SUMO modification on STAT1 to lysine 703. This lysine residue is in close proximity to the regulatory tyrosine residue at position 701, whose phosphorylation mediates STAT1 activation in response to cytokine signaling. Mutation of lysine 703 to arginine abolishes SUMO modification of STAT1 both in vitro and in vivo. However, this mutation does not affect the activation of STAT1 or the ability of either PIAS1 or PIASx-alpha to function as an inhibitor of STAT1-mediated transcription activation. Our findings demonstrate that inhibition of STAT1 by PIAS proteins does not require SUMO modification of STAT1 itself. SUMO modification of STAT1 may nonetheless be functionally important given the close proximity between the SUMO modification site and tyrosine 701.

Intracavernosal vascular endothelial growth factor (VEGF) injection and adeno-associated virus-mediated VEGF gene therapy prevent and reverse venogenic erectile dysfunction in rats

Penile veno-occlusive dysfunction (venogenic erectile dysfunction) is a common cause of erectile dysfunction (ED). We investigated whether vascular endothelial growth factor (VEGF) can be used to prevent and reverse venogenic ED in a rat model. Pharmacological cavernosometry was developed and validated using adult male rats with either arteriogenic or venogenic ED. Castrated animals were treated with intracavernous VEGF as either a recombinant protein (C+VEGF) or adeno-associated virus (AAV)-mediated VEGF gene therapy (C+VEGF gene) in an attempt to prevent the development of venogenic ED. Other animal groups received testosterone replacement (C+testosterone) or intracavernous AAV-LacZ gene (C+LacZ). Animals with documented venogenic ED were treated with intracavernous VEGF in an attempt to reverse their ED. Functional analysis (pharmacological infusion cavernosometry) was performed following treatment. Penile specimens were harvested for immunohistochemistry and electron microscopic evaluation. Castrated rats showed a decrease in papaverine-induced intracavernous pressure and an increase in maintenance and drop rates during pharmacological cavernosometry. These changes were prevented by systemic testosterone and intracavernous VEGF or AAV-VEGF therapy. Moreover, intracavernous VEGF was able to reverse the venogenic ED produced by castration. The quantity of penile smooth muscle detected by alpha actin staining decreased after castration but not in the C+T, C+VEGF, or C+VEGF gene groups. Transmission electron microscopy revealed atrophy of penile smooth muscle cells and nerves in the castrated rats. In VEGF-treated rats, regeneration of smooth muscle and nerves as well as endothelial cell hypertrophy and hyperplasia were the prominent features. In our animal model, systemic testosterone replacement or intracavernous VEGF (protein and VEGF gene) prevented the veno-occlusive dysfunction in castrated animals. In rats with established venous leakage, VEGF treatment reversed the cavernosometric findings of leakage. Intracavernous injection of either VEGF protein or VEGF gene may be a preferred therapy to preserve erectile function in patients in whom testosterone therapy is contraindicated.

Metal transporters that contribute copper to metallochaperones in Saccharomyces cerevisiae

Copper metallochaperones represent a new family of soluble, low-molecular-weight proteins that function to deliver copper to specific sites within a cell. How the metallochaperones acquire their copper, however, is not known. In this study, we have conducted a survey of known metal ion transporters in bakers' yeast, Saccharomyces cerevisiae, to identify those that contribute copper to pathways involving the metallochaperones Atxlp and Lys7p. The results indicatethat, in addition to the well known Ctr1p and Ctr3p high-affinity copper transporters, the metallochaperones can acquire their copper through pathways involving the relatively non-specific divalent metal ion transporter Fet4p and the putative low-affinitycopper transporter Ctr2p. We have examined the localization of Ctr2p using an epitope tagged version of the protein and find that Ctr2p does not localize to the cell surface but may operate at the level of the vacuole to mobilize intracellular copper. Inaddition to Ctrlp, Ctr2p, Ctr3p and Fet4p, other metal transport systems can act as upstream donors of copper for the metallochaperones when copper availability in the medium is increased. Although the nature of these auxiliary systems is unknown, they do not appear to involve the yeast members of the Nramp family of divalent transporters, or uptake mechanisms that involve endocytosis. Since vastly different metal transporters located at either the cell surface or intracellular sites can all contribute copper to metallochaperones, it is unlikely that the metallochaperones directly interact with the metal transporters to obtain the metal.

Erythema multiforme secondary to herpes simplex infection: a case report

BACKGROUND

Erythema multiforme (EM) is a complex disease that may have cutaneous and/or mucosal involvement. The severity may range from mild to severe and potentially life threatening. The literature cites many factors including viruses, infections, and medications as causes. This report documents a patient who developed EM secondary to a herpes simplex viral (HSV) infection.

METHODS

Two weeks following an eruption of herpes labialis, a 20-year-old white female patient developed acutely painful oral and labial ulcers accompanied by target skin lesions. A diagnosis of erythema multiforme (EM) was made. The patient was treated with antivirals, analgesics, and symptomatic therapy.

RESULTS

Nine days after the onset of symptoms, the oral and cutaneous lesions had started to heal and the patient no longer required pain medication.

CONCLUSIONS

Although the etiology of EM is still often unknown, infections with herpes simplex virus have been implicated as a possible precipitating factor. This case illustrates the association of the occurrence of EM with an HSV infection.

Natural history of erythromelalgia: presentation and outcome in 168 patients

OBJECTIVE

To describe the demographics, presentation, and outcome in patients with erythromelalgia--a rare and poorly understood clinical syndrome defined by the triad of red, hot, painful extremities.

DESIGN

Retrospective medical record review with follow-up by survey questionnaire.

SETTING

Large tertiary care medical center.

SUBJECTS

Patients with erythromelalgia examined at the Mayo Clinic, Rochester, Minn, between 1970 and 1994.

INTERVENTION

The medical records of 168 patients were analyzed. Follow-up data, which consisted of answers to 2 survey questionnaires or the most recent information in the medical record from patients still alive and death certificates or reports of death for those deceased patients, were obtained for all but 13 patients.

MAIN OUTCOME MEASURES

Survival, morbidity, and quality of life.

RESULTS

All patients were white; 122 (72.6%) were female, and 46 (27.4%) were male. At presentation, the patients' mean age was 55.8 years (age range, 5-91 years). Symptoms had been present since childhood in 7 patients (4.2%). Six patients (3.6%) had a first-degree relative with erythromelalgia. Symptoms were intermittent in 163 patients (97.0%) and constant in 5 (3.0%). Symptoms predominantly involved feet (148 patients [88.1%]) and hands (43 patients [25.6%]). Kaplan-Meier survival curves revealed a significant decrease in survival compared with that expected in persons of similar age and of the same sex (P<.001). After a mean follow-up of 8.7 years (range, 1.3-20 years), 30 patients (31.9%) reported worsening of, 25 (26.6%) no change in, 29 (30.9%) improvement in, and 10 (10.6%) complete resolution of the symptoms. On a standard health status questionnaire, scores for all but one of the health domains were significantly diminished in comparison with those in the US general population.

CONCLUSION

Erythromelalgia is a syndrome with significantly increased mortality and morbidity compared with the US general population.

Relevant contact sensitivities in patients with the diagnosis of oral lichen planus

BACKGROUND

The concept of contact allergy aggravating or inducing oral lichenoid mucositis diagnosed as oral lichen planus (OLP) is well recognized but somewhat controversial.

OBJECTIVE

We sought to identify clinically relevant contact allergens that may be important in the management of patients with OLP.

METHODS

We retrospectively reviewed patients with OLP who had patch tests performed at Mayo Clinic Rochester and Mayo Clinic Scottsdale from 1994 to 1997 and 1988 to 1997, respectively.

RESULTS

Patch tests were performed on 46 patients with a clinical and histopathologic diagnosis of OLP. Of these, 25 (54%) had positive patch test results. Eighteen (72%) of the patients with positive results had clinically relevant reactions. Of the patients with positive metal reactions, 5 had improvement after removal of the metal prosthesis or restoration. Six others noted that their most troublesome areas were adjacent to metal dental restorations. Six patients with reactions to flavorings and one patient with an acrylate dental retainer sensitivity had improvement after avoiding these allergens.

CONCLUSION

Our findings support the concept that contact allergy to metals, flavorings, and plastics can be important in the pathogenesis and management of patients with oral lichenoid mucositis diagnosed as OLP.

Neurophysiologic and vascular studies in erythromelalgia: a retrospective analysis

Erythromelaigia is a poorly understood clinical syndrome characterized by painful, hot, red extremities. We assessed the frequency and types of abnormalities observed during tests of vascular, peripheral neurophysiologic, and autonomic function in patients with erythromelalgia.Methods Of" 163 charts of patients fulfilling the clinical diagnosis of erythromelalgia. 93 patients underwent vascular studies Five of them had detailed vascular studies in 10 affected lower extremities performed before and during symptoms, fifty-four patients underwent neurophysiologic testing, 27 had autonomic reflex screening (ARS). and two had recordings of peripheral autonomic surface potentials (PASP).Results. Measurements in the toes during symptoms revealed a mean temperature increase of 11.6 C (P = 0,00011 along with a laser flow increase from a mean of 6.8 mL/min per 100 g tissue to 76.5 mL/min per 100 g tissue (P<.0.0001). Baseline TcPO; in the feet decreased by 6.7 mmHg (P = 0.032) during symptoms. Twenty-one of 54 electromyographic recordings were abnormal: all fulfilled the criteria for axonal neuropathy. Seventeen of 27 ARSs and one PASP showed severe postganglionic sudomotor impairment; five of 17 additionally had peripheral adrenergic dysfunction.Conclusions During symptoms, an increase in flow and temperature is accompanied paradoxically by a decrease in oxygenation of the affected area; a high proportion of patients have a distal small fiber neuropathy with selective involvement of cutaneous sympathetic fibers; in addition, large fiber neuropathy is often present.

Clinical assessment and outcome in 70 patients with complaints of burning or sore mouth symptoms

OBJECTIVE

To review a series of patients with a burning or sore mouth for elucidation of associated conditions and treatment outcome.

MATERIAL AND METHODS

We retrospectively studied 70 consecutive patients with a burning or sore mouth who were encountered at a tertiary-care center between 1979 and 1992. Clinical and laboratory findings were summarized, and follow-up data were analyzed.

RESULTS

The study cohort of 56 women and 14 men had a mean age of 59 years. They had had a burning or sore mouth for a mean duration of 2.5 years. Multiple etiologic factors for the burning or sore mouth were present in 37% of the study subjects. The most frequently associated conditions were psychiatric disease (30%), xerostomia (24%), geographic tongue (24%), nutritional deficiencies (21%), and allergic contact stomatitis (13%). With a treatment course tailored to the suspected causal factor, 72% of the patients who had follow-up reported improvement.

CONCLUSION

With a directed investigation, one or more causes could be identified in most patients who had a burning or sore mouth. Successful management of these symptoms was possible in a majority of the patients.

Bullous pemphigoid presenting as generalized pruritus: observations in six patients

BACKGROUND

Bullous pemphigoid is a chronic immunobullous disease of the elderly. Classically, tense, pruritic blisters develop on normal or erythematous skin. These may be preceded by a prodromal pruritic, urticarial, or eczematous eruption. Occasionally, patients may develop generalized pruritus without blisters as a prodrome of bullous pemphigoid.

METHODS

The records of the patients were reviewed. Biopsy specimens were studied by light and immunofluorescence microscopy. Serum specimens were studied by indirect immunofluorescence techniques including the salt-split skin technique.

RESULTS

We studied six elderly patients presenting with generalized pruritus as the dominant or single presenting feature of early bullous pemphigoid. Two of the six had rare vesicles at presentation. All had excoriations and one each presented with minimal urticarial or eczematous papules. Routine skin biopsies were largely nonspecific. All patients had confirmation of their diagnosis by either indirect or direct immunofluorescence testing or both. All six patients had their disease completely controlled by their treatment.

CONCLUSIONS

The clinical presentation of the six patients in our series and the eight previously reported patients should be regarded as an unusual prodromal manifestation of bullous pemphigoid characterized by generalized pruritus without primary skin lesions. This presentation could be described as "pruritic pemphigoid," because it joins the remarkable clinical finding of generalized pruritus with the underlying diagnosis of bullous pemphigoid. Elderly patients with severe or persistent unexplained generalized pruritus merit immunofluorescence testing to exclude bullous pemphigoid as the cause of the generalized pruritus. Establishing an early diagnosis permits the prompt institution of effective therapy with dapsone or systemic corticosteroids with an excellent prognosis for complete control of the disease.

Clinicopathologic correlation of hypocomplementemic and normocomplementemic urticarial vasculitis

BACKGROUND

Urticarial vasculitis is characterized by persistent urticarial lesions with histologic evidence of leukocytoclastic vasculitis. Hypocomplementemic urticarial vasculitis (HUV) is a distinct clinical entity in a subset of patients with urticarial vasculitis.

OBJECTIVE

We examined presentation of urticarial vasculitis and factors predictive of connective tissue disease.

METHODS

The clinical, histologic, and immunologic characteristics of 132 patients with urticarial vasculitis seen at the Mayo Clinic were examined, and features of the hypocomplementemic patients were compared with those of the normocomplementemic patients.

RESULTS

Twenty-four patients (18%) had hypocomplementemia; all were female. Interstitial dermal neutrophilia was seen in 19 biopsy specimens (83%). On direct immunofluorescence (DIF) testing of lesional skin, 23 patients (96%) had a continuous strong granular deposition of immunoreactants along the basement membrane zone compatible with lupus erythematosus in addition to vascular fluorescence. Systemic lupus erythematosus (SLE) was present or occurred in 13 (54%). One hundred eight patients (82%) had normocomplementemia; 65 (60%) were female. Interstitial dermal neutrophilia was seen in 11 of 26 (42%) randomly selected biopsy specimens. On DIF, one patient (1%) had the lupus band. SLE occurred in three patients (3%).

CONCLUSION

Patients with HUV were more likely to be female, to have diffuse neutrophilia on biopsy specimens stained with hematoxylin and eosin, to have continuous strong granular deposition of immunoreactants along the basement membrane zone on DIF, and to have SLE than normocomplementemic patients. We submit that HUV represents a subset of SLE with shared clinical, laboratory, and immunologic features.

American Urological Association symptom index in the assessment of urethroplasty outcomes

PURPOSE

In men undergoing urethroplasty we used the American Urological Association (AUA) symptom index to assess the magnitude of symptoms and determine the validity of this index as an outcome assessment tool.

MATERIALS AND METHODS

The AUA symptom index was completed by individual interview of 50 men a mean of 41 years old who underwent urethral reconstruction. Symptom scores were then correlated with radiographic retrograde urethrograms and urinary flow rates to determine whether changes in the score were consistent with these other clinical indicators of success or failure.

RESULTS

Mean preoperative AUA symptom index score in all evaluable patients was 26.9 (maximum 35), indicating severely bothersome voiding symptoms. In patients with radiographic evidence of successful urethral reconstruction the average postoperative score was 5.1 (p <0.0001). In those with recurrent stricture after urethroplasty scores were essentially unchanged but after successful repeat urethroplasty the mean symptom index score decreased to 3.4 (p <0.0001). A statistically significant inverse correlation (r = -0.712, p <0.0001) was found between AUA symptom index scores and maximum urinary flow rates.

CONCLUSIONS

Patients with urethral strictures who are selected for formal urethroplasty have severe obstructive and irritative voiding symptoms. Results of the AUA symptom index correlate closely with conventional measures of urethroplasty outcome, such as radiographic retrograde urethrography and urinary flow studies. The AUA symptom index appears to have clinical validity as an adjunctive outcome assessment tool after urethroplasty.

Phenytoin-induced linear IgA bullous disease

Drug-induced linear IgA bullous disease most commonly occurs after exposure to vancomycin, but other medications may also trigger the eruption. We describe a 78-year-old man with linear IgA bullous disease related to treatment with phenytoin.

Diseases of the lips

The vermilion of the lips was conceptualized by Jean Darier as the semi-mucosa. The anatomy of the lips is transitional from skin to mucous membrane. This article emphasizes inflammatory diseases of the lips known as cheilitis. Angular cheilitis is a reactive process with several possible causes, including infections, mechanical, nutritional deficiency, and various dermatoses. Contact cheilitis may be caused by a primary irritant or a delayed hypersensitivity allergic reaction to contactants. Plasma cell cheilitis is a reactive periorificial mucositis. Exfoliative cheilitis is also a reactive process, probably secondary to factitious activity of the patient. Cheilitis glandularis is a chronic inflammatory disorder of the labial salivary glands and their ducts. There are three forms: simple, superficial suppurative, and deep suppurative. A premalignant potential is present in cheilitis glandularis. Cheilitis granulomatosa is one manifestation of orofacial granulomatosis. The granulomatous conditions of Melkersson-Rosenthal syndrome, sarcoidosis, and Crohn's disease may be associated with cheilitis granulomatosa or it may stand alone as Miescher's cheilitis. Actinic cheilitis is another premalignant form of cheilitis that is amenable to a variety of therapeutic modalities.

Recurrent aphthous stomatitis in the diagnosis of Behçet's disease

Recurrent aphthous stomatits (RAS) is also known as recurrent oral ulcers, recurrent aphthous ulcers, or simple or complex aphthosis. RAS is the most common inflammatory ulcerative condition of the oral mucosa in North American patients. RAS has been the subject of active investigation along multiple lines of research including epidemiology, immunology, clinical correlations and therapy. Clinical evaluation of the patient requires correct diagnosis of RAS and classification of the disease based on morphology (MIAU, MJAU, HU) and severity (simple versus complex). In order to properly diagnose and treat a patient with lesions of RAS, the clinician must exclude other causes of acute oral ulcers. Complex aphthosis and complex aphthosis variants associated with systemic disorders should be considered. The aphthous-like oral ulcerations of patients with HIV disease represent a challenging differential diagnosis. The association of lesions of RAS with hematinic deficiencies and gastrointestinal diseases provides an opportunity to identify a "correctable cause" which, with appropriate treatment, can result in a remission or substantial lessening of disease activity. Finally, when all of these factors are considered, the evaluation of the patient for Behçet's disease can be continued on firm grounds that one of the major criteria for the diagnosis of Behçet's disease has been met.

Recurrent aphthous stomatitis: clinical characteristics and associated systemic disorders

Recurrent aphthous stomatitis (RAS), commonly known as canker sores, has been reported as recurrent oral ulcers, recurrent aphthous ulcers, or simple or complex aphthosis. RAS is the most common inflammatory ulcerative condition of the oral mucosa in North American patients. One of its variants is the most painful condition of the oral mucosa. Recurrent aphthous stomatitis has been the subject of active investigation along multiple lines of research, including epidemiology, immunology, clinical correlations, and therapy. Clinical evaluation of the patient requires correct diagnosis of RAS and classification of the disease based on morphology (MiAU, MjAU, HU) and severity (simple versus complex). The natural history of individual lesions of RAS is important, because it is the bench mark against which treatment benefits are measured. The lesions of RAS are not caused by a single factor but occur in an environment that is permissive for development of lesions. These factors include trauma, smoking, stress, hormonal state, family history, food hypersensitivity and infectious or immunologic factors. The clinician should consider these elements of a multifactorial process leading to the development of lesions of RAS. To properly diagnose and treat a patient with lesions of RAS, the clinician must identify or exclude associated systemic disorders or "correctable causes." Behçet's disease and complex aphthosis variants, such as ulcus vulvae acutum, mouth and genital ulcers with inflamed cartilage (MAGIC) syndrome, fever, aphthosis, pharyngitis, and adenitis (FAPA) syndrome, and cyclic neutropenia, should be considered. The aphthous-like oral ulcerations of patients with human immunodeficiency virus (HIV) disease represent a challenging differential diagnosis. The association of lesions of RAS with hematinic deficiencies and gastrointestinal diseases provides an opportunity to identify a "correctable cause," which, with appropriate treatment, can result in a remission or substantial lessening of disease activity.

Synthesis and biological evaluation of the 1,5-diarylpyrazole class of cyclooxygenase-2 inhibitors: identification of 4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benze nesulfonamide (SC-58635, celecoxib)

A series of sulfonamide-containing 1,5-diarylpyrazole derivatives were prepared and evaluated for their ability to block cyclooxygenase-2 (COX-2) in vitro and in vivo. Extensive structure-activity relationship (SAR) work was carried out within this series, and a number of potent and selective inhibitors of COX-2 were identified. Since an early structural lead (1f, SC-236) exhibited an unacceptably long plasma half-life, a number of pyrazole analogs containing potential metabolic sites were evaluated further in vivo in an effort to identify compounds with acceptable pharmacokinetic profiles. This work led to the identification of 1i (4-[5-(4-methylphenyl)-3-(trifluoromethyl)- H-pyrazol-1-yl]benzenesulfonamide, SC-58635, celecoxib), which is currently in phase III clinical trials for the treatment of rheumatoid arthritis and osteoarthritis.

Mucosal, genital, and unusual clinical variants of melanoma

To demonstrate the need for a through cutaneous and mucosal examination, we discuss and illustrate the spectrum of mucosal melanomas and unusual clinical variants of melanoma. Although cutaneous areas exposed to sunlight are most vulnerable, melanomas can occur in any site on the skin or mucous membranes. Pigmented nevi as well as mucosal and labial melanotic macules are lesions that simulate oral mucosal melanomas but are not associated with such a poor prognosis. In contrast, the 5-year survival rate for patients with malignant melanomas of the oral mucosa is only 5%. Similarly, the prognosis is poor for patients who have malignant melanomas of the vulva, vagina, male genitalia, or anorectal area; most patients with such lesions are 50 years of age or older. Subungual and plantar areas are common sites of malignant melanomas, and involvement of the eyelid margin portends a poor prognosis. Other rare variants-desmoplastic, amelanotic, and polypoid malignant melanomas-are associated with local recurrences and metastatic lesions. Early diagnosis is the key to proper treatment and improved survival rate for patients with these unusual variants of melanoma. Increased awareness of the wide variety of clinical features of melanoma should lead to earlier diagnosis.

Melkersson-Rosenthal syndrome and orofacial granulomatosis

The Melkersson-Rosenthal syndrome is a rare disorder of unknown etiology characterized by a triad of recurrent orofacial swelling, relapsing facial paralysis, and fissured tongue. Exacerbations and recurrences are common. The orofacial swelling is characterized by fissured, reddish-brown, swollen, nonpruritic lips or firm edema of the face. The facial palsy is indistinguishable from Bell's palsy. The fissured tongue is seen in one third to one half of patients and, although the least common manifestation, its presence assists in diagnosis. The classic triad is not seen frequently in its complete form; therefore, diagnosis is difficult. This is particularly true because monosymptomatic and oligosymptomatic variants are seen more commonly. Cheilitis granulomatosa of Miescher is an example of a monosymptomatic variant of the Melkersson-Rosenthal syndrome. The histologic findings of noncaseating, sarcoidal granulomas support the diagnosis. These granulomas are not invariably present, and their absence does not exclude the diagnosis of the Melkersson-Rosenthal syndrome. Thus, the Melkersson-Rosenthal syndrome is a disease with elements of orofacial granulomatosis. Orofacial granulomatosis is a clinicopathologic entity describing oral lesions with noncaseating granulomas. The spectrum of this entity includes patients with oral Crohn's disease, patients with oral lesions who will develop typical bowel symptoms of Crohn's disease in the ensuing months to years, patients with tooth-associated infections, patients with sarcoidosis, and patients with food or contact allergies. The value of the clinicopathologic construct of orofacial granulomatosis is to provoke the careful search for provocative causes for the reactive symptom complex of the Melkersson-Rosenthal syndrome.