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PubMed2004

Detection of surfactant protein A (SP-A) and surfactant protein D (SP-D) in equine synovial fluid with immunoblotting.

Once considered unique to the lung, surfactant proteins have been clearly identified in the intestine and peritoneum and are suggested to exist in several other organs. In the lung, surfactant proteins assist in the formation of a monolayer of surface-active phospholipid at the liquid-air interface of the alveolar lining, reducing the surface tension at this surface. In contrast, surface-active phospholipid adsorbed to articular surfaces has been identified as the load-bearing boundary lubricant of the joint. This raises the question of whether surfactant proteins in synovial fluid (SF) are required for the formation of the adsorbed layer in normal joints. Proteins from small volumes of equine SF were resolved by 1- and 2-dimensional polyacrylamide gel electrophoresis and detected by Western blotting to investigate the presence of surfactant proteins. The study showed that surfactant proteins A and D (SP-A and SP-D) are present in the SF of normal horses. We suggest that, like surface-active phospholipid, SP-A and SP-D play a significant role in the functioning of joints. Next will be clarification of the roles of surfactant proteins as disease markers in a variety of joint diseases, such as degenerative joint disease and inflammatory problems.

Animals↗

PubMed1990

Dissociation of the DNA polymerase III holoenzyme beta 2 subunits is accompanied by conformational change at distal cysteines 333.

The beta subunit of DNA polymerase III holoenzyme is in a dimer-monomer equilibrium at physiological beta concentrations. Dissociation is accompanied by the fluorescence enhancement of a fluorophore attached to a unique sulfhydryl group of beta (Griep, M. A., and McHenry, C. S. (1988) Biochemistry 27, 5210-5215). Sequencing of the isolated tryptic peptides of beta revealed that the fluorescent maleimide group was attached to cysteine 333. The 2 residues, lysine 332 and glutamate 334, that flank this residue are hydrophilic and may place cysteine 333 on the surface of beta, explaining its high reactivity. Fluorescence energy transfer permitted us to locate the uniquely labeled cysteines 333 of beta at the distal ends of the beta dimer. When the beta dimer was dissociated to monomers, the accompanying alteration of the conformational state was reported by the fluorescein-5-maleimide (fluorescein)-labeled cysteines which were located far from the dimer interface. The carboxyl of fluorescein had a fluorescence pKa of 6.9 when beta was in its dimeric state. The pKa decreased by 0.3 pH unit upon dissociation to monomers and resulted in the fluorescence enhancement that was observed when the signal was monitored at constant pH. The adjacent glutamate 334 apparently increased the pKa of the attached fluorescein when beta was in its dimeric state. Movement of either the adjacent lysine 332 amino side chain to a closer position or glutamate 334 to a position further away could lower the pKa upon beta monomerization. Thus, beta undergoes a conformational change concomitant with dimer dissociation that was transmitted to the opposite ends of the beta dimer. The pKa of fluorescein attached to the distal cysteines was shifted, leading to greater ionization and enhanced fluorescence.

Chromatography, Gel↗

PubMed1994

Acceptability of Unified Medical Language System terms as substitute for natural language general medicine clinic diagnoses.

The acceptability of using the Unified Medical Language System (UMLS) concept phrases to substitute for physicians' diagnosis statements was investigated. Physician diagnosis statements recorded in the University of New Mexico's General Medicine Clinic were input into a computer program that automatically finds the best matching UMLS concept phrases. The computer program written in C++ integrates UMLS searching and browsing with a graphical user interface. Five attending physicians in the Department of Internal Medicine rated the acceptability of the UMLS concept phrase as a substitute for the original physician statement. One hundred and ninety-five patients' notes were examined with 447 diagnosis statements recorded of which 271 statements were unique. Attending physicians rated their satisfaction with the automated UMLS substitutes on a scale of 1 (extremely dissatisfied) to 5 (extremely satisfied). Intrarater (mean 0.94) and interrater correlations (mean 0.75) were high. The mean rating was 4.0 (quite satisfied). Most (73%) of the substitution were satisfactory (rating of 4 or 5), 16% were neutral (rating of 3), and 21% were unsatisfactory (rating of 1 or 2). A review of the substitutions showed a frequent lack of clinical modifier terms in UMLS as has been previously described. Comparison to a previous study shows the broader term coverage of UMLS to be a more acceptable source of diagnosis codes than using International Classification of Diseases revision 9 alone. These results suggest that UMLS can be an effective tool for coding unconstrained physician diagnoses.

Consumer Behavior↗

PubMed2001

Equine placentation.

A tough, elastic glycoprotein capsule envelops the equine blastocyst between Days 6 and 23 after ovulation. It maintains the spherical configuration of, and provides physical support for, the embryo as it traverses the entire uterine lumen during Days 6-17, propelled by myometrial contractions that are stimulated by pulsatile release of prostaglandin F2alpha and prostaglandin E2. The capsule also accumulates constituents of the exocrine secretions of the endometrial glands ('uterine milk') as nutrients for the mobile embryo as it releases its antiluteolytic maternal recognition-of-pregnancy signal to the whole of the surface of the endometrium. Mobility ceases abruptly on Day 17 with a sudden increase in uterine tonicity that 'fixes' the conceptus at the base of one of the uterine horns. At Day 35, the trophoblast of the spherical conceptus has separated into its invasive and non-invasive components. The former, distinguished as the thickened, annulate chorionic girdle, invades the maternal endometrium to form the unique endometrial cups. These secrete a chorionic gonadotrophin that synergizes with pituitary follicle-stimulating hormone to induce secondary luteal development in the maternal ovaries. The cup cells express foreign fetal antigens that stimulate strong maternal humoral and cell-mediated immune responses, which curtail their lifespan. The non-invasive trophoblast of the allantochorion establishes a stable microvillous contact with the endometrial epithelium around Day 40 and, over the next 100 days, develops a complex multibranched interdigitation with the endometrium to form the microcotyledonary haemotrophic exchange units that cover the entire surface of the diffuse epitheliochorial placenta. Reduction in the effective total area of fetomaternal contact at this placental interface, by competition between twin conceptuses for the limited area of available endometrium, by attachment of the allantochorion to an imperfect endometrium in a mare with endometrosis, or following cross-breeding or embryo transfer between a sire and dam of dissimilar size, will all induce intrauterine growth retardation of the fetus and runting of the foal, which persists into adult life. Over 40 years ago, Professor Roger Short and his colleagues determined that the high concentrations of conventional and unique ring B unsaturated oestrogens in the blood and urine of mares during the second half of pregnancy stem from placental aromatization of large quantities of C-19 precursor molecules secreted by the temporarily hypertrophic fetal gonads. Placental production of progesterone and 5alpha-reduced progestagens, on the other hand, depends on both maternal and fetal adrenal sources of pregnenelone.

Allantois↗

PubMed2005

Long-term clinical, radiological and histopathological follow-up of a well-fixed Mckee-Farrar metal-on-metal total hip arthroplasty.

Metal-on-metal is one potential bearing option for total hip arthroplasty (THA). Proponents of the bearing have suggested that if the tribology is optimal, volumetric wear may occur at levels at least one order of magnitude lower than metal-on-polyethylene bearings. We present a unique postmortem case of a well fixed, metal-on-metal, McKee-Farrar total hip arthroplasty implanted 30 years previously that was clinically asymptomatic in life. Clinical and radiological examination is supplemented by tribological examination of the bearing and histopathological examination of the cement-bone interface.

Arthroplasty, Replacement, Hip↗

PubMed2003

Clinical forensic medicine--management of crime victims from trauma to trial.

The loss of human life and function due to violence constitutes a phenomenon that affects millions of patients annually. Society demands an investigation of trauma associated with criminal activity. No longer is it acceptable for health care professionals to operate in isolation of forensic philosophies and principles. It is assumed that the individuals responsible for the performance of the examination of forensic victims have the necessary basic education, experience, and skills. Health care professionals involved in the initial response to these victims, in the emergency department, are faced with unique problems, as social changes require continual reevaluation of standards and professional responsibility. The role of forensic medicine has been expressly designed to provide solutions to some of the most urgent concerns in our society. Forensic medicine focuses on the areas in which medicine and human behavior interface with the law. Existing problems are great and multifaceted and call for new solutions. The application of forensic science to contemporary medical practice reveals a wider role in the investigation of crime and the legal process that contributes to public health and safety. The responsibility of the forensic medicine is to provide continuity of care from the health care institution or the crime scene to courts of law...from trauma to trial.

Journal Article↗

PubMed2004

Crystal structure of the excisionase-DNA complex from bacteriophage lambda.

The excisionase (Xis) protein from bacteriophage lambda is the best characterized member of a large family of recombination directionality factors that control integrase-mediated DNA rearrangements. It triggers phage excision by cooperatively binding to sites X1 and X2 within the phage, bending DNA significantly and recruiting the phage-encoded integrase (Int) protein to site P2. We have determined the co-crystal structure of Xis with its X2 DNA-binding site at 1.7A resolution. Xis forms a unique winged-helix motif that interacts with the major and minor grooves of its binding site using an alpha-helix and an ordered beta-hairpin (wing), respectively. Recognition is achieved through an elaborate water-mediated hydrogen-bonding network at the major groove interface, while the preformed hairpin forms largely non-specific interactions with the minor groove. The structure of the complex provides insights into how Xis recruits Int cooperatively, and suggests a plausible mechanism by which it may distort longer DNA fragments significantly. It reveals a surface on the protein that is likely to mediate Xis-Xis interactions required for its cooperative binding to DNA.

Amino Acid Sequence↗

PubMed2003

PLIF induces IL-10 production in monocytes: a calmodulin-p38 mitogen-activated protein kinase-dependent pathway.

Recently, we reported the cloning and preliminary characterization of a novel human immunomodulator named PLIF (placenta immunomodulatory ferritin). PLIF has a unique molecular structure, which is composed of a ferritin heavy chain-like domain and a novel cytokine-like domain called C48. Both intact molecule and C48 inhibit T cell proliferation following allogeneic or anti-CD3 stimuli. PLIF is localized at the fetal-maternal interface of human placenta and might play a role in down-modulating the maternal immune reaction toward the embryo. The inhibitory effect of PLIF on T cell activation can be direct, indirect through cytokine mediators, or both. In the present study we investigated the possible indirect effects of PLIF by using its bioactive domain C48. Measurement of various cytokines revealed that C48, predominantly, induce pronounced and rapid IL-10 production in monocytes, which is immune activation-independent. Further, we discovered that C48-induced IL-10 production is mediated through a calcium/calmodulin-p38 mitogen-activated protein (MAP) kinase signaling pathway. However, extracellular signal-related kinases1,2 (ERK1,2), also activated by C48 stimulation, exhibited a limiting effect on IL-10 production.

Binding Sites↗

PubMed1997

Tiny T antigen: an autonomous polyomavirus T antigen amino-terminal domain.

Three mRNAs from the murine polyomavirus early region encode the three well-characterized tumor antigens. We report the existence of a fourth alternatively spliced mRNA which encodes a fourth tumor antigen, tiny T antigen, which comprises the amino-terminal domain common to all of the T antigens but is extended by six unique amino acid residues. The amount of tiny T antigen in infected cells is small because of its short half-life. Tiny T antigen stimulates the ATPase activity of Hsc70, most likely because of its DnaJ-like motif. The common amino-terminal domain may interface with chaperone complexes to assist the T antigens in carrying out their diverse functions of replication, transcription, and transformation in the appropriate cellular compartments.

3T3 Cells↗

PubMed2002

Marginal zone macrophages express a murine homologue of DC-SIGN that captures blood-borne antigens in vivo.

Antigen-presenting cells are localized in essentially every tissue, where they operate at the interface of innate and acquired immunity by capturing pathogens and presenting pathogen-derived peptides to T cells. C-type lectins are important pathogen recognition receptors and the C-type lectin, dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN), is unique in that, in addition to pathogen capture, it regulates adhesion processes such as DC trafficking and T-cell synapse formation. We have isolated a murine homologue of DC-SIGN that is identical to the previously reported murine homologue mSIGNR1. mSIGNR1 is more closely related to the human DC-SIGN homologue L-SIGN than to DC-SIGN itself because mSIGNR1 is specifically expressed by liver sinusoidal endothelial cells, similar to L-SIGN, and not by DCs. Moreover, mSIGNR1 is also expressed by medullary and subcapsular macrophages in lymph nodes and by marginal zone macrophages (MZMs) in the spleen. Strikingly, these MZMs are in direct contact with the bloodstream and efficiently capture specific polysaccharide antigens present on the surface of encapsulated bacteria. We have investigated the in vivo function of mSIGNR1 on MZMs in spleen. We demonstrate here that mSIGNR1 functions in vivo as a pathogen recognition receptor on MZMs that capture blood-borne antigens, which are rapidly internalized and targeted to lysosomes for processing. Moreover, the antigen capture is completely blocked in vivo by the blocking mSIGNR1-specific antibodies. Thus, mSIGNR1, a murine homologue of DC-SIGN, is important in the defense against pathogens and this study will facilitate further investigations into the in vivo function of DC-SIGN and its homologues.

Amino Acid Sequence↗

PubMed2005

Gonadotropin-releasing hormone (GnRH) positively regulates corticotropin-releasing hormone-binding protein expression via multiple intracellular signaling pathways and a multipartite GnRH response element in alphaT3-1 cells.

CRH-binding protein (CRH-BP) binds CRH with high affinity and inhibits CRH-mediated ACTH release from anterior pituitary corticotrope-like cells in vitro. In female mouse pituitary, CRH-BP is localized not only in corticotropes, but is also expressed in gonadotropes and lactotropes. To investigate the functional significance of gonadotrope CRH-BP, we examined the molecular mechanisms underlying GnRH-regulated CRH-BP expression in alphaT3-1 gonadotrope-like cells. CRH-BP is endogenously expressed in alphaT3-1 cells, and quantitative real-time RT-PCR and ribonuclease protection assays demonstrate that GnRH induces a 3.7-fold increase in CRH-BP mRNA levels. GnRH also induces intracellular CRH-BP (2.0-fold) and secreted CRH-BP (5.3-fold) levels, as measured by [125I]CRH:CRH-BP chemical cross-linking. Transient transfection assays using CRH-BP promoter-luciferase constructs indicate that GnRH regulation involves protein kinase C-, ERK- and calcium-dependent signaling pathways and is mediated via a multipartite GnRH response element that includes activator protein 1 and cAMP response element (CRE) sites. The CRE site significantly contributes to GnRH responsiveness, independent of protein kinase A, representing a unique form of multipartite GnRH regulation in alphaT3-1 cells. Furthermore, EMSAs indicate that alphaT3-1 nuclear proteins specifically bind at activator protein 1 and CRE sites. These data demonstrate novel regulation of pituitary CRH-BP, highlighting the importance of the pituitary gonadotrope as a potential interface between the stress and reproductive axes.

Activating Transcription Factor 2↗

PubMedDate not supplied

Symmetrical lupoid onychodystrophy in dogs: a retrospective analysis of 18 cases (1989-1993).

A unique, symmetrical onychodystrophy is described in 18 dogs. A rather sudden onset of onychomadesis is followed by chronic onychodystrophy affecting all claws. Pain and lameness are recognized in half of the patients, but the dogs are healthy otherwise. Histopathologically, this disorder is characterized by hydropic and lichenoid interface dermatitis. Nine dogs were treated with a commercial, fatty-acid supplement and had good-to-excellent responses. Due to the clinicopathological characteristics of this disorder, the authors propose the name "symmetrical lupoid onychodystrophy."

Animals↗

PubMed2006

Surfactant protein C: its unique properties and emerging immunomodulatory role in the lung.

Surfactant protein C (SP-C) is a highly hydrophobic protein found in pulmonary surfactant. SP-C is synthesized exclusively in alveolar type II cells as a 21 kDa integral membrane precursor protein and subsequently proteolytically processed to a 3.7 kDa secretory protein. SP-C enhances the adsorption and spreading of phospholipids at the air-liquid interface thereby promoting the surface tension-lowering properties of surfactant. The importance of SP-C in normal lung function is underscored by the recent findings of inflammatory lung diseases associated both with absence of alveolar SP-C and with cellular expression of mutant SP-C isoforms. This review examines our current understanding of the role of SP-C in maintaining alveolar epithelial homeostasis and the potential role of abnormal SP-C expression in the development of lung diseases with particular emphasis on microbial pulmonary infection and inflammation.

Animals↗

PubMed2006

Classification of movement intention by spatially filtered electromagnetic inverse solutions.

We couple standardized low-resolution electromagnetic tomography, an inverse solution for electroencephalography (EEG) and the common spatial pattern, which is here conceived as a data-driven beamformer, to classify the benchmark BCI (brain-computer interface) competition 2003, data set IV. The data set is from an experiment where a subject performed a self-paced left and right finger tapping task. Available for analysis are 314 training trials whereas 100 unlabelled test trials have to be classified. The EEG data from 28 electrodes comprise the recording of the 500 ms before the actual finger movements, hence represent uniquely the left and right finger movement intention. Despite our use of an untrained classifier, and our extraction of only one attribute per class, our method yields accuracy similar to the winners of the competition for this data set. The distinct advantages of the approach presented here are the use of an untrained classifier and the processing speed, which make the method suitable for actual BCI applications. The proposed method is favourable over existing classification methods based on an EEG inverse solution, which rely either on iterative algorithms for single-trial independent component analysis or on trained classifiers.

Algorithms↗

PubMed1980

Adenoid cystic carcinoma of the esophagus: a light and electron microscopic study.

The light and electron microscopic appearances of adenoid cystic carcinoma of the esophagus are presented. Typical light microscopic features of adenoid cystic carcinoma were seen, but a unique additional feature was the presence at one edge of the tumor of gland-like structures lined entirely by tumor cells and opening onto an intact esophageal epithelium. Electron microscopy showed cystic spaces containing replicated basement membrane surrounded by epithelial cells with occasional myoepithelial cells at the interface. Rare lumina were seen between the cells with microvilli projecting into them. Occasional epithelial cells contained granules of neurosecretory tape. Both the light and electron microscopic findings strongly support an origin from the intercalated duct of esophageal mucus glands. The paucity of gland lumina may represent a lesser degree of differentiation which would accord well with the known biological aggressiveness of the tumor at this site.

Basement Membrane↗

PubMed2001

Structural and energetic analysis of RNA recognition by a universally conserved protein from the signal recognition particle.

The signal recognition particle (SRP) is a ribonucleoprotein complex responsible for targeting proteins to the endoplasmic reticulum in eukarya or to the inner membrane in prokarya. The crystal structure of the universally conserved RNA-protein core of the Escherichia coli SRP, refined here to 1.5 A resolution, revealed minor groove recognition of the 4.5 S RNA component by the M domain of the Ffh protein. Within the RNA, nucleotides comprising two phylogenetically conserved internal loops create a unique surface for protein recognition. To determine the energetic importance of conserved nucleotides for SRP assembly, we measured the affinity of the M domain for a series of RNA mutants. This analysis reveals how conserved nucleotides within the two internal loop motifs establish the architecture of the macromolecular interface and position essential functional groups for direct recognition by the protein.

Conserved Sequence↗

PubMed1990

A cooperative hemoglobin with directly communicating hemes. The Scapharca inaequivalvis homodimer.

The unique functional properties of the homodimeric hemoglobin (HbI) extracted from the Arcid blood clam Scapharca inaequivalvis are discussed in the light of the unusual assembly of this protein. At variance with vertebrate hemoglobins, in S. inaequivalvis HbI, the heme-carrying E and F helices form the subunit interface and bring the heme groups almost into direct contact. This creates a new pathway for transferring information about the ligation state of the heme from one subunit to the other which allows cooperativity in the binding of heme ligands to be displayed by a homodimer. The tight coupling between the two subunits and the two heme groups also manifests itself in other reactions that are cooperative in S. inaequivalvis HbI, but not in human hemoglobin, namely, the cleavage of the proximal histidine-heme iron bond and the modification of specific residues located at the subunit interface.

Amino Acid Sequence↗

PubMed2004

Effects of ligand binding and conformational switching on intracellular stability of human thymidylate synthase.

Thymidylate synthase (TS) is the target in colon cancer therapeutic protocols utilizing such drugs as 5-fluorouracil and raltitrexed. The effectiveness of these treatments is hampered by emerging drug resistance, usually related to increased levels of TS. Human TS (hTS) is unique among thymidylate synthases from all species examined as its loop 181-197 can assume two main conformations related by rotation of 180 degrees. In one conformation, "active", the catalytic Cys-195 is positioned in the active site; in the other conformation, "inactive", it is at the subunit interface. Also, in the active conformation, region 107-128 has one well-defined conformation while in the inactive conformation this region assumes multiple conformations and is disordered in crystals. The native protein exists in apparent equilibrium between the two conformational states, while the enzyme liganded with TS inhibitors assumes the active conformation. The native protein has been reported to bind to several mRNAs, including its own mRNA, but upon ligation, RNA binding activity is lost. Ligation of TS by inhibitors also stabilizes it to turnover. Since currently used TS-directed drugs stabilize the active conformation and slow down the enzyme degradation, it is postulated that inhibitors of hTS stabilizing the inactive conformation of hTS should cause a down-regulation in enzyme levels as well as inactivate the enzyme.

Binding Sites↗