Publications by authors named "Richard Alvarez"

44 Publications

Inhibition of P-Selectin and PSGL-1 Using Humanized Monoclonal Antibodies Increases the Sensitivity of Multiple Myeloma Cells to Bortezomib.

Biomed Res Int 2015 11;2015:417586. Epub 2015 Oct 11.

Cancer Biology Division, Department of Radiation Oncology, Washington University in Saint Louis School of Medicine, Saint Louis, MO 63108, USA.

Multiple myeloma (MM) is a plasma cell malignancy localized in the bone marrow. Despite the introduction of novel therapies majority of MM patients relapse. We have previously shown that inhibition of P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) play a key role in proliferation of MM and using small-molecule inhibitors of P-selectin/PSGL-1 sensitized MM cells to therapy. However, these small-molecule inhibitors had low specificity to P-selectin and showed poor pharmacokinetics. Therefore, we tested blocking of P-selectin and PSGL-1 using functional monoclonal antibodies in order to sensitize MM cells to therapy. We have demonstrated that inhibiting the interaction between MM cells and endothelial and stromal cells decreased proliferation in MM cells and in parallel induced loose-adhesion to the primary tumor site to facilitate egress. At the same time, blocking this interaction in vivo led to MM cells retention in the circulation and delayed homing to the bone marrow, thus exposing MM cells to bortezomib which contributed to reduced tumor growth and better mice survival. This study provides a better understanding of the biology of P-selectin and PSGL-1 and their roles in dissemination and resensitization of MM to treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2015/417586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4619821PMC
August 2016

Biomechanical Evaluation of Custom Foot Orthoses for Hallux Valgus Deformity.

J Foot Ankle Surg 2015 Sep-Oct;54(5):852-5. Epub 2015 Jun 6.

Orthopaedic Resident, Department of Orthopaedic Surgery, University of Tennessee College of Medicine, Chattanooga, TN.

The purpose of the present study was to compare the hallux valgus deformity pressure parameters seen in standard footwear (no orthosis) versus the pressure observed in the same footwear with the addition of 3 different length orthoses. The forefoot pressure at a hallux valgus deformity was recorded with pressure sensors placed on the plantar, medial, and dorsal surface of the first metatarsal head. The participants performed walking trials without an orthosis and with orthoses of 3 different lengths. The average pressure and maximum pressure of each area was recorded for each orthosis, and comparisons were made across the groups. The plantar pressures were decreased in the full length and 3/4 length orthoses, and the dorsal pressures were increased with the use of the full-length and sulcus-length orthoses. Significant changes in medial pressure were not seen with the addition of any orthosis compared with standard footwear alone. However, a trend toward increased medial pressures was seen with the full- and sulcus-length orthoses, and the 3/4-length orthoses exhibited a trend toward decreased medial pressures. We were unable to demonstrate that the use of a custom foot orthosis significantly decreases the medial pressures on the first metatarsal head in patients with hallux valgus deformity. The 3/4-length orthosis was less likely to negatively affect the dorsal or medial pressures, which were noted to increase with the sulcus- and full-length orthoses. Our data suggest that if a clinician uses this treatment option, a 3/4-length orthosis might be a better choice than a sulcus- or full-length orthosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.jfas.2015.01.011DOI Listing
May 2016

Nonoperative management of retrocalcaneal pain with AFO and stretching regimen.

Foot Ankle Int 2012 Jul;33(7):571-81

Background: Retrocalcaneal heel pain is caused by a spectrum of etiologies all resulting in the same symptom of pain at the tendon-Achilles insertion. Several studies have reported the outcomes of operative treatment, but none have reported the outcomes or success rates of nonoperative treatment. We describe a detailed treatment algorithm and report the clinical outcomes.

Methods: One hundred thirty-five patients were prescribed a treatment regimen consisting of an AFO and stretching program and were enrolled in our prospective study. One hundred three patients completed pre- and post-treatment Foot Function Indices and were included in the analysis. The effect on FFI from clinical and radiographic factors was examined.

Results: Of the study population, 76% had a BMI greater than 25, 80% were older than 50 years, and 75% had an exostosis on radiographs. The mean pre-treatment FFI was 48.4 and the mean post-treatment FFI was 18.6 indicating a statistically significant improvement in function of 29.8. Neither BMI nor age had a significant effect on the magnitude of improvement; though, smokers had significantly less improvement. FFI improvement in patients with an exostosis were less than those without an exostosis. Patients with an exostosis less than 1 cm had less improvement than those with an exostosis of 1 cm or more. Patients with Types I and III exostoses had significantly less improvement in FFI compared to Types II and IV. Twelve of the 103 (11.6%) were not pleased with the results of nonoperative treatment and elected to have a procedure performed.

Conclusion: Our study is the first to report the outcome of non operatively treated retrocalcaneal heel pain and to classify retrocalcaneal exostoses. Using our treatment algorithm, we had an 88% success rate in alleviating symptoms and avoiding surgery. Our data suggests that the use of an AFO and stretching regimen may benefit patients suffering from retrocalcaneal heel pain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3113/FAI.2012.0571DOI Listing
July 2012

The bisecting GlcNAc in cell growth control and tumor progression.

Glycoconj J 2012 Dec 4;29(8-9):609-18. Epub 2012 Apr 4.

Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA.

The bisecting GlcNAc is transferred to the core mannose residue of complex or hybrid N-glycans on glycoproteins by the β1,4-N-acetylglucosaminyltransferase III (GlcNAcT-III) or MGAT3. The addition of the bisecting GlcNAc confers unique lectin recognition properties to N-glycans. Thus, LEC10 gain-of-function Chinese hamster ovary (CHO) cells selected for the acquisition of ricin resistance, carry N-glycans with a bisecting GlcNAc, which enhances the binding of the erythroagglutinin E-PHA, but reduces the binding of ricin and galectins-1, -3 and -8. The altered interaction with galactose-binding lectins suggests that the bisecting GlcNAc affects N-glycan conformation. LEC10 mutants expressing polyoma middle T antigen (PyMT) exhibit reduced growth factor signaling. Furthermore, PyMT-induced mammary tumors lacking MGAT3, progress more rapidly than tumors with the bisecting GlcNAc on N-glycans of cell surface glycoproteins. In recent years, evidence for a new paradigm of cell growth control has emerged involving regulation of cell surface residency of growth factor and cytokine receptors via interactions and cross-linking of their branched N-glycans with a lattice of galectin(s). Specific cross-linking of glycoprotein receptors in the lattice regulates their endocytosis, leading to effects on growth factor-induced signaling. This review will describe evidence that the bisecting GlcNAc of N-glycans regulates cellular signaling and tumor progression, apparently through modulating N-glycan/galectin interactions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10719-012-9373-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459286PMC
December 2012

Dislocation of the proximal and distal tibiofibular syndesmotic complex without associated fracture: case report.

Foot Ankle Int 2011 Oct;32(10):1009-11

University of Tennessee College of Medicine, Orthopaedic Surgery, 975 East Third St, Hospital Box 287, Chattanooga, TN 37363, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3113/FAI.2011.1009DOI Listing
October 2011

Extracorporeal shock wave treatment of non- or delayed union of proximal metatarsal fractures.

Foot Ankle Int 2011 Aug;32(8):746-54

University of Tennessee College of Medicine, Orthopaedic Surgery, 975 East Third St, Hospital Box 287, Chattanooga, TN 37363, USA.

Background: Nonunion or delayed union of fractures in the proximal aspect of metatarsals 1 to 4 and Zone 2 of the fifth metatarsal were treated by high energy extracorporeal shock wave treatment (ESWT) to study the safety and efficacy of this method of treatment in a FDA study of the Ossatron device.

Materials And Methods: In a prospective single-arm, multi-center study, 34 fractures were treated in 32 patients (two subjects had two independent fractures) with ESWT. All fractures were at least 10 (range, 10 to 833) weeks after injury, with a median of 23 weeks. ESWT application was conducted using a protocol totaling 2,000 shocks for a total energy application of approximately 0.22 to 0.51 mJ/mm2 per treatment. The mean ESWT application time for each of the treatments was 24.6 +/- 16.6 minutes, and anesthesia time averaged 27.1 +/- 10.4 minutes. All subjects were followed for 1 year after treatment at intervals of 12 weeks, 6, 9, and 12 months.

Results: The overall success rate at the 12-week visit was 71% with low complications, significant pain improvement as well as improvement on the SF-36. The success/fail criteria was evaluated again at the 6- and 12-month followup, showing treatment success rates of 89% (23/26) and 90% (18/20), respectively. The most common adverse event was swelling in the foot, reported by five subjects (15.6%).

Conclusion: High-energy ESWT appears to be effective and safe in patients for treatment of nonunion or a delayed healing of a proximal metatarsal, and in fifth metatarsal fractures in Zone 2.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3113/FAI.2011.0746DOI Listing
August 2011

Arteriovenous fistula and pseudoaneurysm of the posterior tibial artery after calcaneal slide osteotomy: a case report.

Foot Ankle Int 2010 Apr;31(4):329-32

University of Tennessee College of Medicine, 975 East Third Street, Chattanooga, TN 37403, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3113/FAI.2010.0329DOI Listing
April 2010

Vaccination-induced IgG response to Galalpha1-3GalNAc glycan epitopes in lambs protected against Haemonchus contortus challenge infection.

Int J Parasitol 2010 Feb 18;40(2):215-22. Epub 2009 Aug 18.

Department of Molecular Cell Biology & Immunology, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.

Lambs vaccinated with Haemonchus contortus excretory/secretory (ES) glycoproteins in combination with the adjuvant Alhydrogel are protected against H. contortus challenge infection. Using glycan micro-array analysis we showed that serum from such vaccinated lambs contains IgG antibodies that recognise the glycan antigen Galalpha1-3GalNAc-R and GalNAcbeta1-4(Fucalpha1-3)GlcNAc-R. Our studies revealed that H. contortus glycoproteins contain Galalpha1-3Gal-R as well as significant levels of Galalpha1-3GalNAc-R, which has not been previously reported. Extracts from H. contortus adult worms contain a galactosyltransferase acting on glycan substrates with a terminal GalNAc, indicating that the worms possess the enzymatic potential to synthesise terminal Gal-GalNAc moieties. These data illustrate that glycan micro-arrays constitute a promising technology for fast and specific analysis of serum anti-glycan antibodies in vaccination studies. In addition, this approach facilitates the discovery of novel, antigenic parasite glycan antigens that may have potential for developing glycoconjugate vaccines or utilization in diagnostics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijpara.2009.07.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813329PMC
February 2010

Glycan microarray analysis of Candida glabrata adhesin ligand specificity.

Mol Microbiol 2008 May;68(3):547-59

Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

The Candida glabrata genome encodes at least 23 members of the EPA (epithelial adhesin) family responsible for mediating adherence to host cells. To better understand the mechanism by which the Epa proteins contribute to pathogenesis, we have used glycan microarray analysis to characterize their carbohydrate-binding specificities. Using Saccharomyces cerevisiae strains surface-expressing the N-terminal ligand-binding domain of the Epa proteins, we found that the three Epa family members functionally identified as adhesins in Candida glabrata (Epa1, Epa6 and Epa7) bind to ligands containing a terminal galactose residue. However, the specificity of the three proteins for glycans within this class varies, with Epa6 having a broader specificity range than Epa1 or Epa7. This result is intriguing given the close homology between Epa6 and Epa7, which are 92% identical at the amino acid level. We have mapped a five-amino-acid region within the N-terminal ligand-binding domain that accounts for the difference in specificity of Epa6 and Epa7 and show that these residues contribute to adherence to both epithelial and endothelial cell lines in vitro.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1365-2958.2008.06184.xDOI Listing
May 2008

Chronic disease management: it's time for transformational change!

Healthc Pap 2007 ;7(4):43-7; discussion 68-70

Innovation and Adoption, Canada Health Infoway.

The authors of the lead essay present a compelling case for the development and implementation of a national strategy on chronic disease prevention and management (CDPM). The literature demonstrates that the Chronic Care Model can improve quality and reduce costs. Substantial evidence supports the role of health information technologies such as electronic health records (EHRs) in achieving these goals. However, an interoperable pan-Canadian health infostructure does not exist; funding is required to establish this across the continuum of care. An investment of $350 per capita would provide a robust health technology platform to support a national CDPM strategy. Such an investment would deliver annual benefits of $6-$7.6 billion; this could be leveraged to support national healthcare priorities such as CDPM. EHRs will improve decisions about care, reduce system errors and increase efficiency. They will also improve our ability to measure, assess and manage care. We cannot run a high-performing health system without sound data. This was a key step to enabling progress on wait times management. Leadership is required if a national CDPM strategy is to become reality. The authors made a convincing case for the development of a national strategy; we need to turn their words into actionable events to gain necessary momentum.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12927/hcpap..18997DOI Listing
August 2007

Biological applications of a chimeric probe for the assessment of galectin-3 ligands.

J Histochem Cytochem 2007 Oct 12;55(10):1015-26. Epub 2007 Jun 12.

Faculdade de Medicina da Universidade de São Paulo, Avenida Dr. Arnaldo 455, 01246-903 São Paulo SP, Brazil.

Beta1-6 branching of N-linked oligosaccharides has been correlated with the progression of different cancers. The leukoagglutinins of Phaseolus vulgaris (L-PHA) have been used to study this pattern of glycosylation whose biological significance is incompletely understood. The animal lectin, galectin-3, also binds to structures recognized by L-PHA. To develop a functional tool for the in situ identification of this pattern of glycosylation, human galectin-3 was fused to bacterial alkaline phosphatase (gal3/AP). Gal3/AP recognized both A and B blood group saccharides (B>A) and lactosamine derivatives. Gal3/AP recognition depended at least in part on the N-linked oligosaccharides of different glycoproteins. The presence and distribution of galectin-3 ligands were analyzed in both murine and human normal and tumor samples. Loss of apical expression of galectin-3 ligands was commonly found in carcinomas. Endothelial and inflammatory cells were enriched in galectin-3 ligands as compared with tumor cells; thus, gal3/AP is a suitable tool for studying tumor microenvironments. Comparative analysis of both gal3/AP and L-PHA binding patterns indicated that although similar, these patterns are not identical. The probe developed was useful for several immunoenzymatic assays and will allow the physiological and clinical significance of the expression pattern of galectin-3 ligands to be established. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1369/jhc.7A7174.2007DOI Listing
October 2007

Identification of ligand specificities for glycan-binding proteins using glycan arrays.

Methods Enzymol 2006 ;415:292-310

Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, USA.

Protein-glycan interactions mediate diverse biological processes in cell communication and innate immunity. They involve the binding of a protein on one cell surface to a glycosylated protein or lipid on an opposing cell surface. Understanding the functional significance of these interactions is of major interest to the scientific community. Numerous studies have demonstrated the utility of solid-phase glycan arrays as a means of identifying glycan binding specificity. These approaches share a common format in that glycans are attached in some manner to a solid-phase surface and the glycan-binding protein (GBP) is presented in solution for binding analysis. Multiple options are available to investigators for detecting these interactions, but the most robust reporters are fluorescence based, and binding can be detected as relative fluorescence units. The solid-phase assays have been proved to be highly scalable and suitable for manufacturing processes. The latest innovations have led to the production of miniaturized arrays using microarray printing technology to produce glycan microarrays with the potential to spot and interrogate several thousands of unique glycans simultaneously. This chapter describes two glycan array platforms developed by the Consortium for Functional Glycomics, a microtiter plate-based array and a covalent printed array, and the analytic methods used to conduct binding specificity assays for a broad range of GBPs and organisms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S0076-6879(06)15018-1DOI Listing
February 2007

A novel family of lectins evolutionarily related to class V chitinases: an example of neofunctionalization in legumes.

Plant Physiol 2007 Jun 10;144(2):662-72. Epub 2006 Nov 10.

Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, 9000 Gent, Belgium.

A lectin has been identified in black locust (Robinia pseudoacacia) bark that shares approximately 50% sequence identity with plant class V chitinases but is essentially devoid of chitinase activity. Specificity studies indicated that the black locust chitinase-related agglutinin (RobpsCRA) preferentially binds to high-mannose N-glycans comprising the proximal pentasaccharide core structure. Closely related orthologs of RobpsCRA could be identified in the legumes Glycine max, Medicago truncatula, and Lotus japonicus but in no other plant species, suggesting that this novel lectin family most probably evolved in an ancient legume species or possibly an earlier ancestor. This identification of RobpsCRA not only illustrates neofunctionalization in plants, but also provides firm evidence that plants are capable of developing a sugar-binding domain from an existing structural scaffold with a different activity and accordingly sheds new light on the molecular evolution of plant lectins.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.106.087981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1914163PMC
June 2007

Specificity of DC-SIGN for mannose- and fucose-containing glycans.

FEBS Lett 2006 Nov 16;580(26):6123-31. Epub 2006 Oct 16.

Department of Molecular Cell Biology and Immunology, VU University Medical Center, Van der Boechorstsraat 7, 1081 BT Amsterdam, The Netherlands.

The dendritic cell specific C-type lectin dendritic cell specific ICAM-3 grabbing non-integrin (DC-SIGN) binds to "self" glycan ligands found on human cells and to "foreign" glycans of bacterial or parasitic pathogens. Here, we investigated the binding properties of DC-SIGN to a large array of potential ligands in a glycan array format. Our data indicate that DC-SIGN binds with K(d)<2muM to a neoglycoconjugate in which Galbeta1-4(Fucalpha1-3)GlcNAc (Le(x)) trisaccharides are expressed multivalently. A lower selective binding was observed to oligomannose-type N-glycans, diantennary N-glycans expressing Le(x) and GalNAcbeta1-4(Fucalpha1-3)GlcNAc (LacdiNAc-fucose), whereas no binding was observed to N-glycans expressing core-fucose linked either alpha1-6 or alpha1-3 to the Asn-linked GlcNAc of N-glycans. These results demonstrate that DC-SIGN is selective in its recognition of specific types of fucosylated glycans and subsets of oligomannose- and complex-type N-glycans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.febslet.2006.10.009DOI Listing
November 2006

Ipsilateral arthrodesis of the metatarsophalangeal and interphalangeal joints of the hallux.

Foot Ankle Int 2006 Oct;27(10):804-7

Department of Orthopaedic Surgery, University of Miami School of Medicine, Miami, FL 33136, USA.

Background: Arthrodesis of the metatarsophalangeal joint of the hallux is frequently used for treatment of a variety of disorders. However, occasionally patients who have complex deformities or degenerative changes of the hallux require reconstruction of both the metatarsophalangeal and interphalangeal joints. There is concern that arthrodesis of both the metatarsophalangeal and ipsilateral interphalangeal joints could be problematic, interfering with the toe-off phase of gait or with shoewear.

Methods: A retrospective evaluation of seven feet in five patients who had simultaneous arthrodesis of the metatarsophalangeal and ipsilateral interphalangeal joints of the hallux was undertaken. These cases represented all the patients who had this procedure within the practice of three orthopaedic foot and ankle specialists, totaling over 50 surgeon-years of experience. The indication for surgery in all patients was moderate to severe pain with ambulation with severe fixed deformity of both the interphalangeal and metatarsophalangeal joints of the hallux. All patients had pain that limited their ambulation and interfered with their daily activities. All patients required modified shoewear to accommodate their foot deformity. The mean age of patients was 53 years. The patients were evaluated by questionnaire and radiographic examination.

Results: At an average of 46 months followup, all patients had resolution of their pain and were able to wear nonprescription shoes. All had limitations that interfered with full athletic activities but had no limitation of daily activities. Three patients who were employed returned to their occupations and two who were not employed were able to continue housework.

Conclusion: Arthrodesis of the metatarsophalangeal and ipsilateral interphalangeal joints of the hallux results in painless function in patients with moderate demands.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/107110070602701009DOI Listing
October 2006

The liverwort Marchantia polymorpha expresses orthologs of the fungal Agaricus bisporus agglutinin family.

Plant Physiol 2007 Jun 13;144(2):637-47. Epub 2006 Oct 13.

Department of Molecular Biotechnology, Laboratory of Biochemistry and Glycobiology, Ghent University, 9000 Ghent, Belgium.

A lectin different from the previously described mannose-binding agglutinins has been isolated from the liverwort Marchantia polymorpha. Biochemical characterization of the purified lectin combined with the data from earlier transcriptome analyses demonstrated that the novel M. polymorpha agglutinin is not related to any of the known plant lectin families, but closely resembles the Agaricus bisporus-type lectins, which hitherto have been found exclusively in fungi. Immunolocalization studies confirmed that lectin is exclusively associated with plant cells, ruling out the possibility of a fungal origin. Extensive screening of publicly accessible databases confirmed that, apart from fungi, the occurrence of A. bisporus-type lectins is confined to M. polymorpha and the moss Tortula ruralis. Expression of a typical fungal protein in a liverwort and a moss raises the question of the origin of the corresponding genes. Regardless of the evolutionary origin, the presence of a functional A. bisporus lectin ortholog in M. polymorpha provides evidence for the expression of an additional carbohydrate-binding domain in Viridiplantae.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.106.087437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1914199PMC
June 2007

Identification of the sialic acid structures recognized by minute virus of mice and the role of binding affinity in virulence adaptation.

J Biol Chem 2006 Sep 5;281(35):25670-7. Epub 2006 Jul 5.

Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, USA.

Sialic acid binding is required for infectious cell surface receptor recognition by parvovirus minute virus of mice (MVM). We have utilized a glycan array consisting of approximately 180 different carbohydrate structures to identify the specific sialosides recognized by the prototype (MVMp) and immunosuppressive (MVMi) strains of MVM plus three virulent mutants of MVMp, MVMp-I362S, MVMp-K368R, and MVMp-I362S/K368R. All of the MVM capsids specifically bound to three structures with a terminal sialic acid-linked alpha2-3 to a common Galbeta1-4GlcNAc motif: Neu5Acalpha2-3Galbeta1-4GlcNAcbeta1-4Galbeta1-4GlcNAc (3'SiaLN-LN), Neu5Acalpha2-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4GlcNAc (3'SiaLN-LN-LN), and Neu5Acalpha2-3Galbeta1-4(Fucalpha1-3)-GlcNAcbeta1-3Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4(Fucalpha1-3)GlcNAc (sLe(x)-Le(x)-Le(x)). In addition, MVMi also recognized four multisialylated glycans with terminal alpha2-8 linkages: Neu5Acalpha2-8Neu5Acalpha2-8Neu5Acalpha ((Sia)(3)), Neu5Acalpha2-8Neu5Acalpha2-3Galbeta1-4Glc (GD3), Neu5Acalpha2-8Neu5Acalpha2-8Neu5Acalpha2-3Galbeta1-4Glc (GT3), and Neu5Acalpha2-8Neu5Acalpha2-3(GalNAcbeta1-4)Galbeta1-4Glc (GD2). Interestingly, the virulent MVMp-K368R mutant also recognized GT3. Analysis of the relative binding affinities using a surface plasmon resonance biospecific interaction (BIAcore) assay showed the wild-type MVMp and MVMi capsids binding with higher affinity to selected glycans compared with the virulent MVMp mutants. The reduced affinity of the virulent MVMp mutants are consistent with previous in vitro cell binding assays that had shown weaker binding to permissive cells compared with wild-type MVMp. This study identifies the sialic acid structures recognized by MVM. It also provides rationale for the tropism of MVM for malignant transformed cells that contain sLe(x) motifs and the neurotropism of MVMi, which is likely mediated via interactions with multisialylated glycans known to be tumor cell markers. Finally, the observations further implicate a decreased binding affinity for sialic acid in the in vivo adaptation of MVMp to a virulent phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M604421200DOI Listing
September 2006

Role of the carbohydrate recognition domains of mouse galectin-4 in oligosaccharide binding and epitope recognition and expression of galectin-4 and galectin-6 in mouse cells and tissues.

Int J Mol Med 2006 Jul;18(1):65-76

Laboratory of Molecular Glycobiology, Department of Recombinant Expression and Structural Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic.

Galectin-4 and its homologue galectin-6 are members of the tandem-repeat subfamily of monomer divalent galectins. Expression of mouse galectin-4 and galectin-6 by RT-PCR using primers designed to distinguish both galectin transcripts indicates that both are expressed in the small intestine, colon, liver, kidney, spleen and heart and P19X1 cells while only galectin-4 is expressed in BW-5147 and 3T3 cell lines. In situ hybridization confirmed the presence of galectin-4/-6 transcripts in the liver and small intestine. Galectin-4 is expressed in spermatozoons and oocytes and its expression during early mouse emryogenesis appears in 8-cell embryos and remains in later stages, as tested by RT-PCR. To study the role of carbohydrate recognition domains (CRDs) in oligosaccharide binding and epitope recognition, we cloned mouse full-length galectin-4 and galectin-6 cDNA and constructed bacterial expression vectors producing histidin-tagged recombinant galectin-4 and its truncated CRD1 and CRD2 forms. Oligosaccharide binding profile for all recombinant forms was assessed using Glycan Array available through the Consortium for Functional Glycomics. Acquired data indicate that mGalectin-4 binds to alpha-GalNAc and alpha-Gal A and B type structures with or without fucose. While the CRD2 domain has a high specificity and affinity for A type-2 alpha-GalNAc structures, the CRD1 domain has a broader specificity in correlation to the total binding profile. These data suggest that CRD2 might be the dominant binding domain of mouse galectin-4. Mapping of epitopes reactive for biotinylated his-tagged CRD1, CRD2 and mGalectin-4 performed on mouse cryosections showed that all three forms bind to alveolar macrophages, macrophages of red pulp of the spleen and proximal tubuli of the kidney and this binding was inhibited by 5 mM lactose. Interestingly, mGalectin-4, but not CRD forms, binds to the suprabasal layer of squamous epithelium of the tongue, suggesting that the link region also plays an important role in ligand recognition.
View Article and Find Full Text PDF

Download full-text PDF

Source
July 2006

Lectin from the Manila clam Ruditapes philippinarum is induced upon infection with the protozoan parasite Perkinsus olseni.

J Biol Chem 2006 Sep 19;281(37):26854-64. Epub 2006 Jun 19.

Department of Medicine, School of Applied Marine Science, Cheju National University, Jeju 690-756, Korea.

Glycan-binding proteins (lectins) are widely expressed in many invertebrates, although the biosynthesis and functions of the lectins are not well understood. Here we report that Manila clam (Ruditapes philippinarum) synthesizes a lectin termed Manila clam lectin (MCL) upon infection with the protozoan parasite Perkinsus olseni. MCL is synthesized in hemocytes as a approximately 74-kDa precursor and secreted into hemolymph where it is converted to 30- and 34-kDa polypeptides. The synthesis of MCL in hemocytes is stimulated by one or more factors in Perkinsus-infected hemolymph, but not directly by Perkinsus itself. MCL can bind to the surfaces of purified hypnospores and zoospores of the parasite, and this binding is inhibitable by either EDTA or GalNAc. Fluorescent beads coated with purified MCL were actively phagocytosed by hemocytes from the clam. Immunohistochemistry showed that secreted MCL is concentrated within cyst-like structures. To define the glycan binding specificity of MCL we examined its binding to an array of biotinylated glycans. MCL recognizes terminal non-reducing beta-linked GalNAc as expressed within the LacdiNAc motif GalNAcbeta1-4GlcNAcbeta1-R and glycans with terminal, non-reducing beta-linked Gal residues. Our results show that the synthesis of MCL is specifically up-regulated upon parasite infection of the clams and may serve as an opsonin through recognition of terminal GalNAc/Gal residues on the parasites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M601251200DOI Listing
September 2006

Biochemical and structural analysis of Helix pomatia agglutinin. A hexameric lectin with a novel fold.

J Biol Chem 2006 Jul 16;281(29):20171-80. Epub 2006 May 16.

Centre de Recherches sur les Macromolécules Végétales, CNRS, Université Joseph Fourier, 38041 Grenoble, France.

Helix pomatia agglutinin (HPA) is a N-acetylgalactosamine (GalNAc) binding lectin found in the albumen gland of the roman snail. As a constituent of perivitelline fluid, HPA protects fertilized eggs from bacteria and is part of the innate immunity system of the snail. The peptide sequence deduced from gene cloning demonstrates that HPA belongs to a family of carbohydrate-binding proteins recently identified in several invertebrates. This domain is also present in discoidin from the slime mold Dictyostelium discoideum. Investigation of the lectin specificity was performed with the use of glycan arrays, demonstrating that several GalNAc-containing oligosaccharides are bound and rationalizing the use of this lectin as a cancer marker. Titration microcalorimetry performed on the interaction between HPA and GalNAc indicates an affinity in the 10(-4) M range with an enthalpy-driven binding mechanism. The crystal structure of HPA demonstrates the occurrence of a new beta-sandwich lectin fold. The hexameric quaternary state was never observed previously for a lectin. The high resolution structure complex of HPA with GalNAc characterizes a new carbohydrate binding site and rationalizes the observed preference for alphaGalNAc-containing oligosaccharides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M603452200DOI Listing
July 2006

Stage I and II posterior tibial tendon dysfunction treated by a structured nonoperative management protocol: an orthosis and exercise program.

Foot Ankle Int 2006 Jan;27(1):2-8

Orthopedics, University of Tennessee College of Medicine, 975 E. Third Street, Hospital Box 287, Chattanooga, TN 37403, USA.

Background: Posterior tibial tendon dysfunction (PTTD) is a relatively common problem of middle-aged adults that usually is treated operatively. The purpose of this study was to identify strength deficits with early stage PTTD and to assess the efficacy of a focused nonoperative treatment protocol.

Methods: Forty-seven consecutive patients with stage I or II posterior tibial tendon dysfunction were treated by a structured nonoperative protocol. Criteria for inclusion were the presence of a palpable and painful posterior tibial tendon, with or without swelling and 2) movement of the tendon with passive and active nonweightbearing clinical examination. The rehabilitation protocol included the use of a short, articulated ankle foot orthosis or foot orthosis, high-repetition exercises, aggressive plantarflexion activities, and an aggressive high-repetition home exercise program that included gastrocsoleus tendon stretching. Isokinetic evaluations were done before and after therapy to compare inversion, eversion, plantarflexion, and dorsiflexion strength in the involved and uninvolved extremities. Criteria for successful rehabilitation were no more than 10% strength deficit, ability to perform 50 single-support heel rises with minimal or no pain, ability to ambulate 100 feet on the toes with minimal or no pain, and ability to tolerate 200 repetitions of the home exercises for each muscle group.

Results: Before therapy weakness for concentric and eccentric contractures of all muscle groups of the involved ankle was significant (p<0.001). After a median of 10 physical therapy visits over a median period of 4 months, 39 (83%) of the 47 patients had successful subjective and functional outcomes, and 42 patients (89%) were satisfied. Five patients (11%) required surgery after failure of nonoperative treatment.

Conclusion: This study suggests that many patients with stage I and II posterior tibial tendon dysfunction can be effectively treated nonoperatively with an orthosis and structured exercises.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/107110070602700102DOI Listing
January 2006

Commentary: The use of external fixation for treatment of complex lower extremity neuropathic arthropathy.

Curr Surg 2005 Nov-Dec;62(6):623-4

Department of Orthopedic Surgery, University of Tennessee College of Medicine, Chattanooga, TN, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cursur.2005.03.013DOI Listing
March 2006

Versatile fluorescent derivatization of glycans for glycomic analysis.

Nat Methods 2005 Nov;2(11):845-50

Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N.E. 10th St., BRC417, Oklahoma City, Oklahoma 73104, USA.

The new field of functional glycomics encompasses information about both glycan structure and recognition by carbohydrate-binding proteins (CBPs) and is now being explored through glycan array technology. Glycan array construction, however, is limited by the complexity of efficiently generating derivatives of free, reducing glycans with primary amines for conjugation. Here we describe a straightforward method to derivatize glycans with 2,6-diaminopyridine (DAP) to generate fluorescently labeled glycans (glycan-DAP conjugates or GDAPs) that contain a primary amine for further conjugation. We converted a wide variety of glycans, including milk sugars, N-glycans, glycosaminoglycans and chitin-derived glycans, to GDAPs, as verified by HPLC and mass spectrometry. We covalently conjugated GDAPs to N-hydroxysuccinimide (NHS)-activated glass slides, maleimide-activated protein, carboxylated microspheres and NHS-biotin to provide quantifiable fluorescent derivatives. All types of conjugated glycans were well-recognized by appropriate CBPs. Thus, GDAP derivatives provide versatile new tools for biologists to quantify and covalently capture minute quantities of glycans for exploring their structures and functions and generating new glycan arrays from naturally occurring glycans.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/nmeth808DOI Listing
November 2005

The electronic health record: a leap forward in patient safety.

Authors:
Richard Alvarez

Healthc Pap 2004 ;5(3):33-6; discussion 82-4

Canada Health Infoway, Canada.

In his review of patient safety issues in the Canadian healthcare system, Dr. Matthew Morgan states that "coordinated national EHR initiatives will cost less, save lives and prevent harm when compared to the status quo." Canada Health Infoway is spearheading this initiative in Canada. Infoway's No. 1 guiding principle for investment is that projects undertaken must "enhance the quality of patient care, healthcare services and patient safety." They must also support the development and adoption of pan-Canadian interoperable EHR solutions. Infoway is working in seven major areas to improve electronic access to accurate and timely health information in order to reduce errors, facilitate accurate diagnoses and speed treatment. These areas include the building blocks of the EHR: infostructure, registries, digital imaging systems, and drug and laboratory information systems. Infoway is also developing and expanding telehealth networks to increase the scope of the Canadian healthcare system. Infoway was recently mandated to develop a public health surveillance system for infectious diseases to give healthcare providers a tool for tracking and managing disease outbreaks in the Canadian population. These systems will improve safety, quality, accessibility, cost-efficiency and the sustainability of the healthcare system. Patient safety is a cornerstone of Infoway's activities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12927/hcpap.2004.16862DOI Listing
November 2005

Carbohydrate specificity of an insecticidal lectin isolated from the leaves of Glechoma hederacea (ground ivy) towards mammalian glycoconjugates.

Biochem J 2006 Jan;393(Pt 1):331-41

Glyco-immunochemistry Research Laboratory, Institute of Molecular and Cellular Biology, College of Medicine, Chang-Gung University, Kwei-San, Tao-Yuan, 333, Taiwan.

Preliminary studies indicated that the potent insecticidal lectin, Gleheda, from the leaves of Glechoma hederacea (ground ivy) preferentially agglutinates human erythrocytes carrying the Tn (GalNAcalpha1-Ser/Thr) antigen. However, no details have been reported yet with respect to the fine specificity of the lectin. To corroborate the molecular basis of the insecticidal activity and physiological function of Gleheda, it is necessary to identify the recognition factors that are involved in the Gleheda-glycotope interaction. In the present study, the requirement of high-density multivalent carbohydrate structural units for Gleheda binding and a fine-affinity profile were evaluated using ELLSA (enzyme-linked lectinosorbent assay) with our extended glycan/ligand collections, a glycan array and molecular modelling. From the results, we concluded that a high-density of exposed multivalent Tn-containing glycoproteins (natural armadillo and asialo ovine salivary glycoproteins) were the most potent factors for Gleheda binding. They were, on a nanogram basis, 6.5x10(5), 1.5x10(4) and 3.1x10(3) times more active than univalent Gal (galactose), GalNAc (N-acetylgalactosamine) and Tn respectively. Among mono- and oligo-saccharides examined, simple clustered Tn (molecular mass <3000 Da) from ovine salivary glycoprotein was the best, being 37.5 and 1.7x10(3) times better than GalNAc and Gal respectively. GalNAc glycosides were significantly more active than Gal glycosides, indicating that the N-acetamido group at C-2 plays an important role in Gleheda binding. The results of glycan array support the conclusions drawn with respect to the specificity of Gleheda based on the ELLSA assays. These findings combined with the results of the molecular modelling and docking indicate the occurrence of a primary GalNAcalpha1-binding site in the Gleheda monomer. However, the extraordinary binding feature of Gleheda for glycoproteins demonstrates the importance of affinity enhancement by high-density multivalent glycotopes in the ligand-lectin interactions in biological processes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/BJ20051162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1383692PMC
January 2006

Health care has to move into the hi-tech age.

Authors:
Richard Alvarez

Bull World Health Organ 2005 May 24;83(5):323. Epub 2005 Jun 24.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org//S0042-96862005000500003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626226PMC
May 2005

Carbohydrate profiling reveals a distinctive role for the C-type lectin MGL in the recognition of helminth parasites and tumor antigens by dendritic cells.

Int Immunol 2005 May 31;17(5):661-9. Epub 2005 Mar 31.

Department of Molecular Cell Biology & Immunology, VU Medical Center, Amsterdam, The Netherlands.

Dendritic cells (DCs) are key to the maintenance of peripheral tolerance to self-antigens and the orchestration of an immune reaction to foreign antigens. C-type lectins, expressed by DCs, recognize carbohydrate moieties on antigens that can be internalized for processing and presentation. Little is known about the exact glycan structures on self-antigens and pathogens that are specifically recognized by the different C-type lectins and how this interaction influences DC function. We have analyzed the carbohydrate specificity of the human C-type lectin macrophage galactose-type lectin (MGL) using glycan microarray profiling and identified an exclusive specificity for terminal alpha- and beta-linked GalNAc residues that naturally occur as parts of glycoproteins or glycosphingolipids. Specific glycan structures containing terminal GalNAc moieties, expressed by the human helminth parasite Schistosoma mansoni as well as tumor antigens and a subset of gangliosides, were identified as ligands for MGL. Our results indicate an endogenous function for DC-expressed MGL in the clearance and tolerance to self-gangliosides, and in the pattern recognition of tumor antigens and foreign glycoproteins derived from helminth parasites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/intimm/dxh246DOI Listing
May 2005

Plantar fasciopathy and orthotripsy: the effect of prior cortisone injection.

Foot Ankle Int 2005 Mar;26(3):231-3

Skeletal Educational Association, 3435 Habsersham Rd., NW, Atlanta, GA 30305, USA.

Background: Corticoid steroid injection into the heel is a popular treatment method for painful heel syndromes. However, the positive results usually are short term. Extracorporeal shock wave treatment (ESW) has been shown to have a more permanent effect. We evaluated 555 patients who received ESW using the device Ossa Tron Orthotripsy (Health Tronics, Surgical Services, Marietta, GA) relative to antecedent cortisone heel injection.

Methods: Before ESW, 312 patients (56%) received one or more cortisone injections into the heel, and 243 patients (44%) had never received a cortisone injection.

Results: Two hundred and thirty-four patients (75%) who had antecedent injection or injections had positive outcomes after ESW. One hundred sixty-eight patients (69%) without prior heel injection had positive responses after ESW.

Conclusion: The prior injection of cortisone did not affect the likelihood of a positive response to ESW. Similarly, the absence of prior injection of cortisone did not affect the outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/107110070502600308DOI Listing
March 2005
-->