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1.
Ir J Med Sci ; 192(1): 317-319, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35132568

ABSTRACT

OBJECTIVE: The vast majority of breast cancers are diagnosed via image-guided procedures yet despite significant advances, imaging does not identify all breast malignancies. Clinically suspicious breast lesions with normal breast imaging remain a cause for concern. The aim of this study is to determine the diagnostic value of clinical core and cutaneous punch biopsies in the diagnosis of breast malignancy in clinically suspicious lesions with normal breast imaging. METHODS: All patients with suspicious clinical breast findings and normal imaging who underwent a clinical core and/or cutaneous punch biopsy from 2012 to 2019 were reviewed retrospectively. Patients with subsequent breast malignant diagnosis were analysed. RESULTS: A total of 283 biopsies (166 clinical core, 117 cutaneous punch) performed over the 7-year period were included in the analysis. A total of 263/283 (93%) yielded a benign outcome. A total of 2/283 (0.7%) yielded B3 lesions (probably benign). These lesions were benign on final surgical excision. A total of 18/283 (6.3%) yielded a malignant histopathology. Sixteen out of 18 were cutaneous punch biopsies, and 2/18 were clinical core biopsies. A total of 14/18 patients presented with nipple changes, while 4/18 had a palpable area of concern. Histopathological analysis demonstrated Paget's disease of the nipple in 8/18, invasive carcinoma in 9/18 out of which two represented a recurrence of breast malignancy. Cutaneous squamous cell carcinoma was diagnosed in 1/18. CONCLUSION: Clinical core and cutaneous punch biopsies remain a valuable tool in the diagnosis of breast cancer particularly in the management of clinically suspicious radiographically occult malignancies.


Subject(s)
Breast Neoplasms , Carcinoma, Squamous Cell , Skin Neoplasms , Humans , Female , Mammography , Retrospective Studies , Biopsy , Breast Neoplasms/pathology , Biopsy, Large-Core Needle
2.
Clin Breast Cancer ; 22(7): 699-704, 2022 10.
Article in English | MEDLINE | ID: mdl-35732544

ABSTRACT

INTRODUCTION: B3 lesions are a heterogeneous group of breast lesions of uncertain malignant potential which usually require excision. The aim was to assess the efficacy of 5 years routine radiological or clinical follow-up of patients who had "high-risk" B3 lesions surgically excised, by analyzing recurrence and subsequent development of invasive/in-situ cancer. PATIENTS AND METHODS: A 10-year retrospective review from 2010 to 2019 was performed of B3 lesions diagnosed on core needle biopsy, including patients who proceeded to surgical excision with a high-risk lesion on final histology. The database recorded 6 specific B3 lesion categories: 1. Atypical ductal hyperplasia (ADH), 2. Radial scars/complex sclerosing lesions (CSLs) with epithelial atypia 3. Classical Lobular neoplasia (ALH/LCIS), 4. Papillary lesions with epithelial atypia, 5. Mixed, 6. Flat epithelial atypia (FEA), including radiological and clinical follow-up data. RESULTS: Six hundred sixteen patients had a B3 lesion after core biopsy. 110 patients had "high risk" lesions. This included 17 (15.5%) Atypical Ductal Hyperplasia (ADH), 22 (20%) radial scars/CSLs with epithelial atypia, 47 (42.7%) classical lobular neoplasia (LCIS/ALH), 7 (6.4%) papillary lesions with epithelial atypia, 13 (11.8%) mixed lesions & 4 (3.6%) Flat Epithelial Atypia (FEA) lesions. 4 of 110 (3.6%) developed invasive/in-situ disease and 4 of 110 (3.6%) developed recurrence during follow-up. 33 of 616 (5.4%) upgraded to invasive/preinvasive disease after surgical excision. CONCLUSION: Five years of routine radiological surveillance may not be necessary in patients who undergo surgical excision of "high-risk" B3 lesions. Clinical surveillance appears to be of little benefit, especially in patients with radial scars, papillary lesions, and FEA. Subsequent development of invasive/in-situ disease in patients who undergo surgical excision of atypical B3 lesions remains low.


Subject(s)
Breast Neoplasms , Carcinoma in Situ , Carcinoma, Intraductal, Noninfiltrating , Fibrocystic Breast Disease , Precancerous Conditions , Biopsy, Large-Core Needle , Breast/diagnostic imaging , Breast/pathology , Breast/surgery , Breast Neoplasms/pathology , Breast Neoplasms/surgery , Carcinoma, Intraductal, Noninfiltrating/pathology , Cicatrix/etiology , Female , Fibrocystic Breast Disease/pathology , Follow-Up Studies , Humans , Mammography , Precancerous Conditions/pathology , Retrospective Studies
3.
J Microbiol Biol Educ ; 23(1)2022 Apr.
Article in English | MEDLINE | ID: mdl-35496699

ABSTRACT

Gateway college science courses continue to exclude students from science, disproportionately discriminating against students of color. As the higher education system strives to reduce discrimination, we need a deliberate, iterative process to modify, supplement, or replace current modalities. By incorporating antiracist, just, equitable, diverse, and inclusive (AJEDI) principles throughout course design, instructors create learning environments that provide an antidote to historically oppressive systems. In this paper, we describe how a community of microbiology instructors who all teach Tiny Earth, a course-based undergraduate research experience, created and rapidly integrated antiracist content and pivoted to an online format in response to the social unrest and pandemic of 2020. The effort strengthened an existing teaching community of practice and produced collective change in classrooms across the nation. We provide a perspective on how instructor communities of practice can be leveraged to design and disseminate AJEDI curriculum.

4.
Transl Vis Sci Technol ; 11(3): 18, 2022 03 02.
Article in English | MEDLINE | ID: mdl-35289836

ABSTRACT

Purpose: The purpose of this study was to improve the diagnostic ability of the optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) probability (p-) map by understanding the frequency and pattern of artifacts seen on the p-maps of healthy control (HC) eyes resembling glaucomatous damage. Methods: RNFL p-maps were generated from wide-field OCT cube scans of 2 groups of HC eyes, 200 from a commercial normative group (HC-norm) and 54 from a prospective study group, as well as from 62 patient eyes, which included 32 with early glaucoma (EG). These 32 EG eyes had 24-2 mean deviation (MD) better than -6 dB and perimetric glaucoma as defined by 24-2 and 10-2 criteria. For the HC groups, "glaucoma-like" arcuates were defined as any red region near the temporal half of the disc. Results: Seven percent of the 200 HC-norm and 11% of the 54 HC RNFL p-maps satisfied the definition of "glaucoma-like," as did all the patients' p-maps. The HC p-maps showed two general patterns of abnormal regions, "arcuate" and "temporal quadrant," and these patterns resembled those seen on some of the RNFL p-maps of the EG eyes. A "vertical midline" rule, which required the abnormal region to cross the vertical midline through the fovea, had a specificity of >99%, and a sensitivity of 75% for EG and 93% for moderate to advanced eyes. Conclusions: Glaucoma-like artifacts on RNFL p-maps are relatively common and can masquerade as arcuate and/or widespread/temporal damage. Translational Relevance: A vertical midline rule had excellent specificity. However, other OCT information is necessary to obtain high sensitivity, especially in eyes with early glaucoma.


Subject(s)
Glaucoma , Tomography, Optical Coherence , Artifacts , Cross-Sectional Studies , Glaucoma/diagnosis , Humans , Intraocular Pressure , Nerve Fibers , Probability , Prospective Studies , Retinal Ganglion Cells , Tomography, Optical Coherence/methods
5.
Cancers (Basel) ; 13(6)2021 Mar 11.
Article in English | MEDLINE | ID: mdl-33799597

ABSTRACT

BACKGROUND: Activation of the phosphoinositide-3 kinase (PI3K) pathway is a resistance mechanism to anti-human epidermal growth factor receptor 2 (HER2) therapy. This phase Ib trial was conducted to determine the maximum tolerated dose (MTD) of copanlisib, an intravenous (IV) pan-class I PI3K inhibitor, combined with trastuzumab. METHODS: Patients with advanced HER2-positive breast cancer and disease progression following at least one prior line of HER2 therapy in the metastatic setting were treated with copanlisib (45 or 60 mg) IV on days 1, 8 and 15 of a 28-day cycle with a fixed dose of trastuzumab 2 mg/kg weekly. RESULTS: Twelve patients were enrolled. The MTD was determined as copanlisib 60 mg plus trastuzumab 2 mg/kg weekly. The most common adverse events of any grade occurring in more than two patients were hyperglycaemia (58%), fatigue (58%), nausea (58%) and hypertension (50%). Stable disease was confirmed at 16 weeks in six participants (50%). PIK3CA mutations were detected in archival tumour of six participants (50%). PIK3CA hotspot mutations, were detectable in pre- and on-treatment plasma of all participants. Pre- and post-treatment tumour biopsies for two patients identified temporal genomic heterogeneity, somatic mutations in the TRRAP gene, which encodes a PI3K-like protein kinase, and emergent somatic mutations related to protein kinase signalling. CONCLUSION: Copanlisib and trastuzumab can be safely administered with fair overall tolerability. Preliminary evidence of tumour stability was observed in patients with heavily pre-treated, metastatic HER2 positive breast cancer. Several potential biomarkers were identified for further study in the current phase 2 clinical trial. NCT: 02705859.

6.
Breast Cancer Res Treat ; 187(2): 303-310, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33837870

ABSTRACT

INTRODUCTION: The non-invasive nature of the preoperative axillary ultrasound (AUS) fits the current trend of increasingly conservative axillary management. Recent publications suggest that early disease patients with clinically and radiologically negative axillae do not require sentinel lymph node biopsy (SLNB). This study aims to determine the true extent of axillary node disease in negative preoperative AUS patients. METHODS: A 10-year breast cancer registry was reviewed to identify women with pathologically confirmed T1-2 invasive breast cancer and a negative preoperative AUS. Patients who received neoadjuvant chemotherapy were excluded. Combined positive lymph node count of SLNB ± ALND was used to determine total nodal burden (TNB). Axillae were classified into low nodal burden (LNB) defined as 1-2 positive nodes and high nodal burden (HNB) defined as ≥ 3 positive nodes. RESULTS: 762 patients with negative AUS were included. There were 46.9% and 53.0% T1 and T2 tumours, respectively. 76.9% were node negative (0 LN +), 18.9% had LNB (1-2 LN +) and 4.2% had HNB (≥ 3LN +). Specifically, HNB disease was seen in 2% of T1 tumours and 6.2 % of T2 tumours with a negative AUS. In multivariate analysis, T2 strongly associated with ≥ 3 positive ALNs (OR 2.66 CI 1.09-6.51 p = 0.03) as did lymphovascular invasion (OR 3.56 CI 1.52-8.30 p = < 0.01). CONCLUSION: This study shows that AUS in its current form cannot exclude HNB axillary metastasis to the extent of eliminating the need for surgical staging of the axilla. This may impact axillary local-regional recurrence and disease-free survival. We caution that a negative AUS has a rate of 4.2% of HNB. Therefore, in cases of negative AUS with a T2 tumour, we advocate continued use of SLNB.


Subject(s)
Breast Neoplasms , Axilla/pathology , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/pathology , Breast Neoplasms/therapy , Female , Humans , Lymph Node Excision , Lymph Nodes/diagnostic imaging , Lymph Nodes/pathology , Lymph Nodes/surgery , Lymphatic Metastasis , Neoplasm Recurrence, Local , Neoplasm Staging , Sentinel Lymph Node Biopsy
7.
Article in English | MEDLINE | ID: mdl-33884089

ABSTRACT

Using nontoxic craft items and disposable lab consumables, we have developed nine modules to teach fundamental, hands-on microbiology lab skills safely at home. These "Crafty" teaching modules can be paired with virtual instruction and/or data collected by an instructor to replicate traditional microbiology lab exercises that characterize an unknown microbe. Materials and procedures used were carefully chosen to best mimic the texture of media, represent microbial diversity, assess aseptic technique, and produce analyzable data from results. Some protocols build upon and extend previously unpublished ideas, while others provide novel methods. The lab skills include proper personal protective equipment usage and basic biosafety, aseptic technique, microscopy and staining, streaking for isolation, spread plating, serial dilutions, filtering, disk diffusion method, and modeling an epidemic. Each protocol includes a student handout with background, links to videos of the methods performed with microbes, a rationale for the pairing of craft and consumable lab supplies along with technique used, a video or image demonstration of the "Crafty" technique when needed, postlab questions, and an instructor guide. This resource was developed for an undergraduate microbiology course, and each lab is aligned with learning outcomes within the American Society for Microbiology's undergraduate curriculum guidelines. This work would also be useful for outreach and K-12 educators. The development of microbiology lab skills by all students, regardless of economic or health status, will lead to a more scientifically minded society.

8.
Front Pharmacol ; 5: 87, 2014.
Article in English | MEDLINE | ID: mdl-24808864

ABSTRACT

A ubiquitous post-translational modification observed in proteins is isomerization of aspartic acid to isoaspartic acid (isoAsp). This non-enzymatic post-translational modification occurs spontaneously in proteins and plays a role in aging, autoimmune response, cancer, neurodegeneration, and other diseases. Formation of isoAsp is also a significant issue for recombinant monoclonal antibody based protein therapeutics particularly when isomerization occurs in a complementarity-determining region due to potential impact to the clinical efficacy. Here, we present and compare three analytical methods to monitor and/or quantify isoAsp formation in a monoclonal antibody. The methods include two peptide map based technologies with quantitation from either UV integration or total ion peak areas, as well as an alternative approach using IdeS digestion to generate Fc/2 and Fab'2 regions, followed by hydrophobic interaction chromatography (HIC) to separate the population of Fab'2 containing an isoAsp. The level of isoAsp detected by the peptide map and the digested-HIC methods presented here show similar trends although sample throughput varies by method.

9.
Environ Toxicol Chem ; 33(7): 1552-62, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24648306

ABSTRACT

Anionic polyacrylamide (PAM) products are commonly used to remove suspended materials from turbid waters and to help mitigate soil erosion. In the present study, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 3 mg/L to 300 mg/L of 10 commercially available PAM products (Clearflow Water Lynx Polymer Log and Clearflow Soil Lynx Granular Polymer; Clearflow Enviro Systems Group), and gill histological parameters were measured following either 7 d or 30 d of polymer exposure. A cationic polymer product (≤0.38 mg/L MagnaFloc 368; Ciba Specialty Chemical) was also tested for comparison. Mild gill lesions were observed in fish exposed to polymer products. Lamellar fusion, interlamellar hyperplasia, epithelial lifting, mucous cell metaplasia, and cell counts of epithelial swelling and necrosis/apoptosis were minimal in fish exposed to environmentally relevant concentrations of anionic polymer (≤30 mg/L). Gill morphology was largely unaffected by exposure to concentrations up to 300 mg/L of many PAM products. Several anionic polymer products noticeably affected gill tissue by increasing epithelial hypertrophy, interlamellar hyperplasia, mucous cell metaplasia, and the frequency of necrotic cells. The severity of the lesions lessened with time, suggesting that fish may have experienced a short-term irritant effect. Similar levels of gill pathology were frequently observed in fish exposed to cationic polymer MagnaFloc 368 despite the concentration being 1000-fold lower than that of the PAM products. These observations highlight the increased toxicity of cationic polymers to aquatic life compared with anionic PAMs.


Subject(s)
Acrylic Resins/toxicity , Gills/drug effects , Gills/ultrastructure , Oncorhynchus mykiss/anatomy & histology , Water Pollutants, Chemical/toxicity , Animals , Anions/toxicity , Oncorhynchus mykiss/growth & development
10.
PLoS One ; 9(3): e91696, 2014.
Article in English | MEDLINE | ID: mdl-24626479

ABSTRACT

Porphyromonas gingivalis is a gram-negative anaerobic bacterium, a member of the human oral microbiome, and a proposed "keystone" pathogen in the development of chronic periodontitis, an inflammatory disease of the gingiva. P. gingivalis is a genetically diverse species, and is able to exchange chromosomal DNA between strains by natural competence and conjugation. In this study, we investigate the role of horizontal DNA transfer as an adaptive process to modify behavior, using the major fimbriae as our model system, due to their critical role in mediating interactions with the host environment. We show that P. gingivalis is able to exchange fimbrial allele types I and IV into four distinct strain backgrounds via natural competence. In all recombinants, we detected a complete exchange of the entire fimA allele, and the rate of exchange varies between the different strain backgrounds. In addition, gene exchange within other regions of the fimbrial genetic locus was identified. To measure the biological implications of these allele swaps we compared three genotypes of fimA in an isogenic background, strain ATCC 33277. We demonstrate that exchange of fimbrial allele type results in profound phenotypic changes, including the quantity of fimbriae elaborated, membrane blebbing, auto-aggregation and other virulence-associated phenotypes. Replacement of the type I allele with either the type III or IV allele resulted in increased invasion of gingival fibroblast cells relative to the isogenic parent strain. While genetic variability is known to impact host-microbiome interactions, this is the first study to quantitatively assess the adaptive effect of exchanging genes within the pan genome cloud. This is significant as it presents a potential mechanism by which opportunistic pathogens may acquire the traits necessary to modify host-microbial interactions.


Subject(s)
Fimbriae, Bacterial/genetics , Gene Transfer, Horizontal , Periodontitis/genetics , Porphyromonas gingivalis/genetics , Alleles , Fimbriae Proteins/genetics , Fimbriae Proteins/metabolism , Genetic Variation , Genotype , Humans , Periodontitis/microbiology , Periodontitis/pathology , Phenotype , Porphyromonas gingivalis/pathogenicity , Virulence/genetics
11.
Future Microbiol ; 8(5): 607-20, 2013 May.
Article in English | MEDLINE | ID: mdl-23642116

ABSTRACT

Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that colonizes the human oral cavity. It is implicated in the development of periodontitis, a chronic periodontal disease affecting half of the adult population in the USA. To survive in the oral cavity, these bacteria must colonize dental plaque biofilms in competition with other bacterial species. Long-term survival requires P. gingivalis to evade host immune responses, while simultaneously adapting to the changing physiology of the host and to alterations in the plaque biofilm. In reflection of this highly variable niche, P. gingivalis is a genetically diverse species and in this review the authors summarize genetic diversity as it relates to pathogenicity in P. gingivalis. Recent studies revealing a variety of mechanisms by which adaptive changes in genetic content can occur are also reviewed. Understanding the genetic plasticity of P. gingivalis will provide a better framework for understanding the host-microbe interactions associated with periodontal disease.


Subject(s)
Genetic Variation , Porphyromonas gingivalis/genetics , Porphyromonas gingivalis/pathogenicity , Adaptation, Physiological , Host-Pathogen Interactions , Humans , Mouth/microbiology , Periodontitis/microbiology , Virulence
12.
mBio ; 3(1)2012.
Article in English | MEDLINE | ID: mdl-22294679

ABSTRACT

UNLABELLED: Porphyromonas gingivalis is a Gram-negative anaerobe that resides exclusively in the human oral cavity. Long-term colonization by P. gingivalis requires the bacteria to evade host immune responses while adapting to the changing host physiology and alterations in the composition of the oral microflora. The genetic diversity of P. gingivalis appears to reflect the variability of its habitat; however, little is known about the molecular mechanisms generating this diversity. Previously, our research group established that chromosomal DNA transfer occurs between P. gingivalis strains. In this study, we examine the role of putative DNA transfer genes in conjugation and transformation and demonstrate that natural competence mediated by comF is the dominant form of chromosomal DNA transfer, with transfer by a conjugation-like mechanism playing a minor role. Our results reveal that natural competence mechanisms are present in multiple strains of P. gingivalis, and DNA uptake is not sensitive to DNA source or modification status. Furthermore, extracellular DNA was observed for the first time in P. gingivalis biofilms and is predicted to be the major DNA source for horizontal transfer and allelic exchange between strains. We propose that exchange of DNA in plaque biofilms by a transformation-like process is of major ecological importance in the survival and persistence of P. gingivalis in the challenging oral environment. IMPORTANCE: P. gingivalis colonizes the oral cavities of humans worldwide. The long-term persistence of these bacteria can lead to the development of chronic periodontitis and host morbidity associated with tooth loss. P. gingivalis is a genetically diverse species, and this variability is believed to contribute to its successful colonization and survival in diverse human hosts, as well as evasion of host immune defenses and immunization strategies. We establish here that natural competence is the major driving force behind P. gingivalis DNA exchange and that conjugative DNA transfer plays a minor role. Furthermore, we reveal for the first time the presence of extracellular DNA in P. gingivalis biofilms, which is most likely the source of DNA exchanged between strains within dental plaque. These studies expand our understanding of the mechanisms used by this important member of the human oral flora to transition its relationship with the host from a commensal to a pathogenic relationship.


Subject(s)
Bacterial Proteins/metabolism , DNA Transformation Competence , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Gene Transfer, Horizontal , Porphyromonas gingivalis/genetics , Bacteroidaceae Infections/microbiology , Biofilms/growth & development , Conjugation, Genetic , Humans , Mouth/microbiology , Porphyromonas gingivalis/pathogenicity , Transformation, Bacterial
13.
J Bacteriol ; 193(10): 2566-74, 2011 May.
Article in English | MEDLINE | ID: mdl-21421757

ABSTRACT

Agrobacterium VirB7, VirB9, and VirB10 form a "core complex" during biogenesis of the VirB/VirD4 type IV secretion system (T4SS). VirB10 spans the cell envelope and, in response to sensing of ATP energy consumption by the VirB/D4 ATPases, undergoes a conformational change required for DNA transfer across the outer membrane (OM). Here, we tested a model in which VirB10 regulates substrate passage by screening for mutations that allow for unregulated release of the VirE2 secretion substrate to the cell surface independently of target cell contact. One mutation, G272R, conferred VirE2 release and also rendered VirB10 conformationally insensitive to cellular ATP depletion. Strikingly, G272R did not affect substrate transfer to target cells (Tra(+)) but did block pilus production (Pil(-)). The G272R mutant strain displayed enhanced sensitivity to vancomycin and SDS but did not nonspecifically release periplasmic proteins or VirE2 truncated of its secretion signal. G272 is highly conserved among VirB10 homologs, including pKM101 TraF, and in the TraF X-ray structure the corresponding Gly residue is positioned near an α-helical domain termed the antenna projection (AP), which is implicated in formation of the OM pore. A partial AP deletion mutation (ΔAP) also confers a Tra(+) Pil(-) phenotype; however, this mutation did not allow VirE2 surface exposure but instead allowed the release of pilin monomers or short oligomers to the milieu. We propose that (i) G272R disrupts a gating mechanism in the core chamber that regulates substrate passage across the OM and (ii) the G272R and ΔAP mutations block pilus production at distinct steps of the pilus biogenesis pathway.


Subject(s)
Agrobacterium tumefaciens/pathogenicity , Bacterial Outer Membrane Proteins/metabolism , Macromolecular Substances/metabolism , Membrane Transport Proteins/metabolism , Mutation, Missense , Virulence Factors/metabolism , Adenosine Triphosphate/metabolism , Agrobacterium tumefaciens/chemistry , Agrobacterium tumefaciens/genetics , Agrobacterium tumefaciens/metabolism , Bacterial Outer Membrane Proteins/chemistry , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/metabolism , Conserved Sequence , DNA Mutational Analysis , DNA-Binding Proteins/metabolism , Fimbriae, Bacterial/metabolism , Ion Channels/metabolism , Macromolecular Substances/chemistry , Membrane Transport Proteins/chemistry , Membrane Transport Proteins/genetics , Protein Conformation , Protein Transport , Sequence Homology, Amino Acid , Virulence Factors/chemistry , Virulence Factors/genetics
14.
Bioorg Med Chem Lett ; 20(23): 6890-4, 2010 Dec 01.
Article in English | MEDLINE | ID: mdl-21030256

ABSTRACT

The trifluoromethylphenyl P2 motif from previously reported heteroarylnitrile series has been successfully applied for the design and synthesis of highly potent novel ketoamide-based cathepsin S inhibitors. The key in this process is the change of the torsion angle between the P2 phenyl ring and the attached secondary amide by adding a small Cl, F, or Me group at the 2-position.


Subject(s)
Aniline Compounds/chemical synthesis , Cathepsins/antagonists & inhibitors , Cysteine Proteinase Inhibitors/chemical synthesis , Amides/chemical synthesis , Amides/pharmacology , Aniline Compounds/pharmacology , Animals , Cysteine Proteinase Inhibitors/pharmacology , Fluorine , Humans , Ketones , Structure-Activity Relationship
15.
Bioorg Med Chem Lett ; 20(21): 6237-41, 2010 Nov 01.
Article in English | MEDLINE | ID: mdl-20843687

ABSTRACT

Several structure-guided optimisation strategies were explored in order to improve the hERG selectivity profile of cathepsin K inhibitor 1, whilst maintaining its otherwise excellent in vitro and in vivo profile. Ultimately, attenuation of clogP and pK(a) properties proved a successful approach and led to the discovery of a potent analogue 23, which, in addition to the desired selectivity over hERG (>1000-fold), displayed a highly attractive overall profile.


Subject(s)
Cathepsin K/antagonists & inhibitors , Ether-A-Go-Go Potassium Channels/drug effects , Nitriles/chemical synthesis , Nitriles/pharmacology , Potassium Channel Blockers/chemical synthesis , Potassium Channel Blockers/pharmacology , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , Drug Design , Drug Discovery , Indicators and Reagents , Models, Molecular , ROC Curve , Structure-Activity Relationship , Torsades de Pointes/drug therapy
16.
Protein Sci ; 19(11): 2152-63, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20836085

ABSTRACT

Novel acetone and aldimine covalent adducts were identified on the N-termini and lysine side chains of recombinant monoclonal antibodies. Photochemical degradation of citrate buffers, in the presence of trace levels of iron, is demonstrated as the source of these modifications. The link between degradation of citrate and the observed protein modifications was conclusively established by tracking the citrate decomposition products and protein adducts resulting from photochemical degradation of isotope labeled (13)C citrate by mass spectrometry. The structure of the acetone modification was determined by nuclear magnetic resonance (NMR) spectroscopy on modified-free glycine and found to correspond to acetone linked to the N-terminus of the amino acid through a methyl carbon. Results from mass spectrometric fragmentation of glycine modified with an acetone adduct derived from (13)C labeled citrate indicated that the three central carbons of citrate are incorporated onto protein amines in the presence of iron and light. While citrate is known to stoichiometrically decompose to acetone and CO(2) through various intermediates in photochemical systems, it has never been shown to be a causative agent in protein carbonylation. Our results point to a previously unknown source for the generation of reactive carbonyl species. This work also highlights the potential deleterious impact of trace metals on recombinant protein therapeutics formulated in citrate buffers.


Subject(s)
Acetone/chemistry , Antibodies, Monoclonal/chemistry , Citrates/chemistry , Recombinant Proteins/chemistry , Animals , Antibodies, Monoclonal/metabolism , CHO Cells , Carbon Isotopes/chemistry , Chromatography, High Pressure Liquid , Cricetinae , Cricetulus , Glycine/chemistry , Humans , Imines/chemistry , Immunoglobulin G , Iron/chemistry , Isotope Labeling , Mass Spectrometry , Nuclear Magnetic Resonance, Biomolecular , Photochemical Processes , Protein Carbonylation , Recombinant Proteins/metabolism
17.
J Bacteriol ; 192(19): 4923-34, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20656905

ABSTRACT

Agrobacterium VirB2 pilin is required for assembly of the VirB/VirD4 type IV secretion system (T4SS). The propilin is processed by signal sequence cleavage and covalent linkage of the N and C termini, and the cyclized pilin integrates into the inner membrane (IM) as a pool for assembly of the secretion channel and T pilus. Here, by use of the substituted cysteine accessibility method (SCAM), we defined the VirB2 IM topology and then identified distinct contributions of the T4SS ATPase subunits to the pilin structural organization. Labeling patterns of Cys-substituted pilins exposed to the membrane-impermeative, thiol-reactive reagent 3-(N-maleimidopropionyl)biocytin (MPB) supported a topology model in which two hydrophobic stretches comprise transmembrane domains, an intervening hydrophilic loop (residues 90 to 94) is cytoplasmic, and the hydrophilic N and C termini joined at residues 48 and 121 form a periplasmic loop. Interestingly, the VirB4 ATPase, but not a Walker A nucleoside triphosphate (NTP) binding motif mutant, induced (i) MPB labeling of Cys94, a residue that in the absence of the ATPase is located in the cytoplasmic loop, and (ii) release of pilin from the IM upon osmotic shock. These findings, coupled with evidence for VirB2-VirB4 complex formation by coimmunoprecipitation, support a model in which VirB4 functions as a dislocation motor to extract pilins from the IM during T4SS biogenesis. The VirB11 ATPase functioned together with VirB4 to induce a structural change in the pilin that was detectable by MPB labeling, suggestive of a role for VirB11 as a modulator of VirB4 dislocase activity.


Subject(s)
Agrobacterium tumefaciens/metabolism , Bacterial Proteins/metabolism , Agrobacterium tumefaciens/genetics , Agrobacterium tumefaciens/ultrastructure , Bacterial Proteins/genetics , Fimbriae Proteins/genetics , Fimbriae Proteins/metabolism , Immunoblotting , Immunoprecipitation , Kalanchoe/microbiology , Microscopy, Electron , Models, Biological , Mutation/genetics , Mutation/physiology , Plant Leaves/microbiology , Virulence/genetics , Virulence/physiology
19.
Org Biomol Chem ; 8(12): 2777-83, 2010 Jun 21.
Article in English | MEDLINE | ID: mdl-20424795

ABSTRACT

The addition of various nucleophiles to a vinyl 1,2,4-oxadiazole is described. Following optimisation, individual protocols tuned for the use of each specific class of reagent have been developed to allow the installation of nitrogen, sulfur, oxygen, and carbon nucleophiles, and leading to the preparation of a series of compounds containing the pharmaceutically important oxadiazole motif.


Subject(s)
Oxadiazoles/chemical synthesis , Vinyl Compounds/chemical synthesis , Carbon/chemistry , Nitrogen/chemistry , Oxadiazoles/chemistry , Oxygen/chemistry , Sulfur/chemistry , Vinyl Compounds/chemistry
20.
Bioorg Med Chem Lett ; 20(5): 1524-7, 2010 Mar 01.
Article in English | MEDLINE | ID: mdl-20149657

ABSTRACT

Morphing structural features of HTS-derived chemotypes led to the discovery of novel 2-cyano-pyrimidine inhibitors of cathepsin K with good pharmacokinetic profiles, for example, compound 20 showed high catK potency (IC(50)=4nM), >580-fold selectivity over catL and catB, and oral bioavailability in the rat of 52%.


Subject(s)
Cathepsin K/antagonists & inhibitors , Cysteine Proteinase Inhibitors/chemistry , Pyrimidines/chemistry , Administration, Oral , Animals , Binding Sites , Cathepsin K/metabolism , Cell Line , Crystallography, X-Ray , Cysteine Proteinase Inhibitors/chemical synthesis , Cysteine Proteinase Inhibitors/pharmacokinetics , Drug Design , High-Throughput Screening Assays , Humans , Pyrimidines/chemical synthesis , Pyrimidines/pharmacokinetics , Rats , Rats, Sprague-Dawley , Structure-Activity Relationship
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