Records |
Author |
Carroll, J.; Murphy, C.J.; Neitz, M.; Hoeve, J.N.; Neitz, J. |
Title |
Photopigment basis for dichromatic color vision in the horse |
Type |
Journal Article |
Year |
2001 |
Publication |
Journal of Vision |
Abbreviated Journal |
J Vis |
Volume |
1 |
Issue |
2 |
Pages |
80-87 |
Keywords |
Adaptation, Physiological; Animals; Color Perception/*physiology; Cones (Retina)/chemistry/*physiology; Electroretinography; Horses/*physiology; Photic Stimulation; Phototransduction/physiology; Retinal Pigments/analysis/*physiology; Visual Perception/physiology |
Abstract |
Horses, like other ungulates, are active in the day, at dusk, dawn, and night; and, they have eyes designed to have both high sensitivity for vision in dim light and good visual acuity under higher light levels (Walls, 1942). Typically, daytime activity is associated with the presence of multiple cone classes and color-vision capacity (Jacobs, 1993). Previous studies in other ungulates, such as pigs, goats, cows, sheep and deer, have shown that they have two spectrally different cone types, and hence, at least the photopigment basis for dichromatic color vision (Neitz & Jacobs, 1989; Jacobs, Deegan II, Neitz, Murphy, Miller, & Marchinton, 1994; Jacobs, Deegan II, & Neitz, 1998). Here, electroretinogram flicker photometry was used to measure the spectral sensitivities of the cones in the domestic horse (Equus caballus). Two distinct spectral mechanisms were identified and are consistent with the presence of a short-wavelength-sensitive (S) and a middle-to-long-wavelength-sensitive (M/L) cone. The spectral sensitivity of the S cone was estimated to have a peak of 428 nm, while the M/L cone had a peak of 539 nm. These two cone types would provide the basis for dichromatic color vision consistent with recent results from behavioral testing of horses (Macuda & Timney, 1999; Macuda & Timney, 2000; Timney & Macuda, 2001). The spectral peak of the M/L cone photopigment measured here, in vivo, is similar to that obtained when the gene was sequenced, cloned, and expressed in vitro (Yokoyama & Radlwimmer, 1999). Of the ungulates that have been studied to date, all have the photopigment basis for dichromatic color vision; however, they differ considerably from one another in the spectral tuning of their cone pigments. These differences may represent adaptations to the different visual requirements of different species. |
Address |
Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA |
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English |
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Edition |
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ISSN |
1534-7362 |
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Notes |
PMID:12678603 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4060 |
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Author |
Gilmanshin, R.; Callender, R.H.; Dyer, R.B. |
Title |
The core of apomyoglobin E-form folds at the diffusion limit |
Type |
Journal Article |
Year |
1998 |
Publication |
Nature Structural Biology |
Abbreviated Journal |
Nat Struct Biol |
Volume |
5 |
Issue |
5 |
Pages |
363-365 |
Keywords |
Animals; Apoproteins/*chemistry; Diffusion; Horses; Myoglobin/*chemistry; *Protein Folding; Spectroscopy, Fourier Transform Infrared; Temperature |
Abstract |
The E-form of apomyoglobin has been characterized using infrared and fluorescence spectroscopies, revealing a compact core with native like contacts, most probably consisting of 15-20 residues of the A, G and H helices of apomyoglobin. Fast temperature-jump, time-resolved infrared measurements reveal that the core is formed within 96 micros at 46 degrees C, close to the diffusion limit for loop formation. Remarkably, the folding pathway of the E-form is such that the formation of a limited number of native-like contacts is not rate limiting, or that the contacts form on the same time scale expected for diffusion controlled loop formation. |
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Edition |
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ISSN |
1072-8368 |
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Notes |
PMID:9586997 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3795 |
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Author |
Steinhoff, H.J. |
Title |
A continuous wave laser T-jump apparatus and its application to chemical reactions in hemoglobin single crystals |
Type |
Journal Article |
Year |
1988 |
Publication |
Journal of Biochemical and Biophysical Methods |
Abbreviated Journal |
J Biochem Biophys Methods |
Volume |
15 |
Issue |
6 |
Pages |
319-330 |
Keywords |
Animals; Chemistry; Crystallization; *Heat; *Hemoglobins; Horses/blood; *Lasers; Methemoglobin; Solutions; Thermodynamics; Thiocyanates |
Abstract |
A laser temperature jump apparatus is constructed where the T-jump is achieved by means of the direct absorption of continuous laser radiation of low intensity by a solid sample. The final temperature in the irradiated volume element is reached when the absorbed radiation power equals the dissipation of heat by heat conduction. The time range from the beginning of irradiation to the stationary state depends on the geometry of the irradiated volume element and is less than 10 ms. The heating laser beam is simultaneously used to detect the relaxation to the new chemical equilibrium in the sample. Relaxation processes with relaxation rates between 10(2) s-1 and less than 10(-3) s-1 on samples with volumes less than 10(-3) mm3 may be investigated using this T-jump method. One application of this method is the determination of reaction rates of ligand reactions in hemoglobin single crystals. Rate constants obtained for the reaction of thiocyanate with crystallized horse methemoglobin are presented. |
Address |
Institut fur Biophysik, Ruhr-Universitat Bochum, F.R.G |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0165-022X |
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Conference |
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Notes |
PMID:3379245 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3804 |
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Author |
Traversa, D.; Otranto, D.; Iorio, R.; Giangaspero, A. |
Title |
Molecular characterization of Thelazia lacrymalis (Nematoda, Spirurida) affecting equids: a tool for vector identification |
Type |
Journal Article |
Year |
2005 |
Publication |
Molecular and Cellular Probes |
Abbreviated Journal |
Mol Cell Probes |
Volume |
19 |
Issue |
4 |
Pages |
245-249 |
Keywords |
Animals; Horse Diseases/parasitology; Horses/*parasitology; Insect Vectors/*parasitology; Muscidae/*parasitology; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Spirurida Infections/parasitology/veterinary; Thelazioidea/chemistry/*genetics |
Abstract |
Equine thelaziosis caused by the eyeworm Thelazia lacrymalis is a parasitic disease transmitted by muscid flies. Although equine thelaziosis is known to have worldwide distribution, information on the epidemiology and presence of the intermediate hosts of T. lacrymalis is lacking. In the present work, a PCR-RFLP based assay on the first and/or second internal transcribed spacer (ITS1 and ITS2) of ribosomal DNA was developed for the detection of T. lacrymalis DNA in its putative vector(s). The sensitivity of the technique was also assessed. The restriction patterns obtained readily differentiated T. lacrymalis from four species of Musca (Diptera, Muscidae) (i.e. Musca autumnalis, Musca domestica, Musca larvipara and Musca osiris), which are potential vectors of equine eyeworms. The molecular assay presented herein is a useful tool to identify the intermediate host(s) of T. lacrymalis in natural conditions and to study its/their ecology and epidemiology. |
Address |
Department of Biomedical Comparative Sciences, Faculty of Veterinary Medicine, University of Teramo, Piazza Aldo Moro 45, 64100 Teramo, Italy. dtraversa@unite.it |
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English |
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Series Issue |
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Edition |
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ISSN |
0890-8508 |
ISBN |
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Medium |
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Conference |
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Notes |
PMID:16038792 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2626 |
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Author |
Chiba, K.; Ikai, A.; Kawamura-Konishi, Y.; Kihara, H. |
Title |
Kinetic study on myoglobin refolding monitored by five optical probe stopped-flow methods |
Type |
Journal Article |
Year |
1994 |
Publication |
Proteins |
Abbreviated Journal |
Proteins |
Volume |
19 |
Issue |
2 |
Pages |
110-119 |
Keywords |
Animals; Chromatography, Gel; Circular Dichroism; Horses; Kinetics; Metmyoglobin/analogs & derivatives/chemistry; Myoglobin/*chemistry; *Protein Folding; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Urea |
Abstract |
The refolding kinetics of horse cyanometmyoglobin induced by concentration jump of urea was investigated by five optical probe stopped-flow methods: absorption at 422 nm, tryptophyl fluorescence at around 340 nm, circular dichroism (CD) at 222 nm, CD at 260 nm, and CD at 422 nm. In the refolding process, we detected three phases with rate constants of > 1 x 10(2) s-1, (4.5-9.3) s-1, and (2-5) x 10(-3) s-1. In the fastest phase, a substantial amount of secondary structure (approximately 40%) is formed within the dead time of the CD stopped-flow apparatus (10.7 ms). The kinetic intermediate populated in the fastest phase is shown to capture a hemindicyanide, suggesting that a “heme pocket precursor” recognized by hemindicyanide must be constructed within the dead time. In the middle phase, most of secondary and tertiary structures, especially around the captured hemindicyanide, have been constructed. In the slowest phase, we detected a minor structural rearrangement accompanying the ligand-exchange reaction in the fifth coordination of ferric iron. We present a possible model for the refolding process of myoglobin in the presence of the heme group. |
Address |
Laboratory of Biodynamics, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa, Japan |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0887-3585 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
PMID:8090705 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3799 |
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Author |
Aviad, A.D.; Houpt, J.B. |
Title |
The molecular weight of therapeutic hyaluronan (sodium hyaluronate): how significant is it? |
Type |
Journal Article |
Year |
1994 |
Publication |
The Journal of rheumatology |
Abbreviated Journal |
J Rheumatol |
Volume |
21 |
Issue |
2 |
Pages |
297-301 |
Keywords |
Animals; Horse Diseases/drug therapy; Horses; Humans; Hyaluronic Acid/*chemistry/*therapeutic use; Joint Diseases/*drug therapy/veterinary; Molecular Weight; Osteoarthritis/drug therapy/veterinary; Synovial Fluid/drug effects/physiology; Viscosity |
Abstract |
Various molecular weight hyaluronic acid (HA) preparations have been injected into joints for the treatment of human and equine osteoarthritis. A therapeutic advantage has been claimed for commercial products with a molecular weight in the range found in normal synovial fluid (SF), compared to lower molecular weight products. But a correlation between molecular weight and efficacy is not borne out by an analysis of the available literature on clinical results. SF viscosity, HA concentration, HA molecular weight and rate of synthesis in joint disease. It is proposed that the beneficial effect of injected HA in joint disease may be due to pharmacological rather than to physical properties. |
Address |
Rheumatic Disease Unit, Mount Sinai Hospital, University of Toronto, ON, Canada |
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English |
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Series Issue |
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Edition |
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ISSN |
0315-162X |
ISBN |
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Notes |
PMID:8182640 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
35 |
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Author |
Miksovska, J.; Larsen, R.W. |
Title |
Photothermal studies of pH induced unfolding of apomyoglobin |
Type |
Journal Article |
Year |
2003 |
Publication |
Journal of Protein Chemistry |
Abbreviated Journal |
J Protein Chem |
Volume |
22 |
Issue |
4 |
Pages |
387-394 |
Keywords |
Acoustics; Animals; Apoproteins/*chemistry/metabolism; Circular Dichroism; Horses; Myocardium/chemistry; Myoglobin/*chemistry/metabolism; Photolysis; Protein Conformation/radiation effects; Protein Denaturation/radiation effects; *Protein Folding; Temperature; Thermodynamics |
Abstract |
Conformational dynamic and enthalpy changes associated with pH induced unfolding of apomyoglobin were studied using photoacoustic calorimetry and photothermal beam deflection methods. The transition between the native state and the I intermediate was induced by a nanosecond pH jump from o-nitrobenzaldehyde photolysis. Deconvolution of photoacoustic waves indicates two kinetic processes. The fast phase (T < 50 ns) is characterized by a volume expansion of 8.8 ml mol(-1). This process is followed by a volume contraction of about -22 ml mol(-1) (tau approximately 500 ns). Photothermal beam deflection measurements do not reveal any volume changes on the time scale between approximately 100 micros and 5 ms. We associate the volume contraction with structural changes occurring during the transition between the native state and the I intermediate. The lack of any processes on the ms time scale may indicate the absence of structural events involving larger conformational changes of apomyoglobin after the pH jump. |
Address |
Department of Chemistry, University of South Florida, Tampa, Florida 33620, USA |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0277-8033 |
ISBN |
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Conference |
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Notes |
PMID:13678303 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3780 |
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Author |
Abbruzzetti, S.; Viappiani, C.; Sinibaldi, F.; Santucci, R. |
Title |
Kinetics of histidine dissociation from the heme Fe(III) in N-fragment (residues 1-56) of cytochrome c |
Type |
Journal Article |
Year |
2004 |
Publication |
The Protein Journal |
Abbreviated Journal |
Protein J |
Volume |
23 |
Issue |
8 |
Pages |
519-527 |
Keywords |
Animals; Cytochromes c/*chemistry; Enzyme Activation; Histidine/*chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; Lasers; Ligands; Peptide Mapping; Photolysis; Spectrophotometry |
Abstract |
We have here investigated the dissociation kinetics of the His side chains axially ligated to the heme-iron in the ferric (1-56 residues) N-fragment of horse cyt c. The ligand deligation induced by acidic pH-jump occurs as a biexponential process with different pre-exponential factors, consistent with a structural heterogeneity in solution and the presence of two differently coordinated species. In analogy with GuHCl-denatured cyt c, our data indicate the presence in solution of two ferric forms of the N-fragment characterized by bis-His coordination, as summarized in the following scheme: His18-Fe(III)-His26 <==> His18-Fe(III)-His33. We have found that the pre-exponential factors depend on the extent of the pH-jump. This may be correlated with the different pKa values shown by His26 and His33; due to steric factors, His26 binds to the heme-Fe(III) less strongly than His33, as recently shown by studies on denatured cyt c. Interestingly, the two lifetimes are affected by temperature but not by the extent of the pH-jump. The lower pKa for the deligation reaction required the use of an improved laser pH-jump setup, capable of inducing changes in H+ concentration as large as 1 mM after the end of the laser pulse. For the ferric N-fragment, close activation entropy values have been determined for the two histidines coordinated to the iron; this result significantly differs from that for GuHCl-denatured cyt c, where largely different values of activation entropy were calculated. This underlines the role played by the missing segment (residues 57-104) peptide chain in discriminating deligation of the “nonnative” His from the sixth coordination position of the metal. |
Address |
Dipartimento di Fisica, Universita degli Studi di Parma, Parco Area delle Scienze 7/A 43100 Parma, Italy |
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English |
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Series Volume |
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Edition |
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ISSN |
1572-3887 |
ISBN |
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Notes |
PMID:15648974 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3770 |
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Author |
Nicol, C.J.; Yoon, M.; Ward, J.M.; Yamashita, M.; Fukamachi, K.; Peters, J.M.; Gonzalez, F.J. |
Title |
PPARgamma influences susceptibility to DMBA-induced mammary, ovarian and skin carcinogenesis |
Type |
Journal Article |
Year |
2004 |
Publication |
Carcinogenesis |
Abbreviated Journal |
Carcinogenesis |
Volume |
25 |
Issue |
9 |
Pages |
1747-1755 |
Keywords |
9,10-Dimethyl-1,2-benzanthracene/*toxicity; Animals; DNA Primers/chemistry; Disease Susceptibility; Female; Heterozygote; Humans; Mammary Neoplasms, Experimental/chemically induced/*pathology; Mice; Ovarian Neoplasms/chemically induced/*pathology; RNA, Messenger/genetics/metabolism; Receptors, Cytoplasmic and Nuclear/genetics/*physiology; Reverse Transcriptase Polymerase Chain Reaction; Skin Neoplasms/chemically induced/*pathology; Survival Rate; Transcription Factors/genetics/*physiology; Zinc Fingers |
Abstract |
Peroxisome proliferator-activated receptor gamma (PPARgamma), a member of the nuclear receptor superfamily, plays a role in adipocyte differentiation, type II diabetes, macrophage response to inflammation and is suggested to influence carcinogen-induced colon cancer. Studies done in vitro and in vivo also revealed that PPARgamma ligands might promote differentiation and/or regression of mammary tumors. To directly evaluate the role of PPARgamma in mammary carcinogenesis, PPARgamma wild-type (+/+) or heterozygous (+/-) mice were administered 1 mg 7,12-dimethylbenz[a]anthracene (DMBA) by gavage once a week for 6 weeks and followed for a total of 25 weeks. Compared with congenic PPARgamma(+/+) littermate controls, PPARgamma(+/-) mice had early evidence for increased susceptibility to DMBA-mediated carcinogenesis based on a 1.6-fold increase in the percentage of mice with skin papillomas, as well as a 1.7-fold increase in the numbers of skin papillomas per mouse (P < 0.05). Similarly, PPARgamma(+/-) mice also had a 1.5-fold decreased survival rate (P = 0.059), and a 1.7-fold increased incidence of total tumors per mouse (P < 0.01). Moreover, PPARgamma(+/-) mice had an almost 3-fold increase in mammary adenocarcinomas (P < 0.05), an over 3-fold increase in ovarian granulosa cell carcinomas (P < 0.05), an over 3-fold increase in malignant tumors (P < 0.02) and a 4.6-fold increase in metastatic incidence. These results are the first to demonstrate an increased susceptibility in vivo of PPARgamma haploinsufficiency to DMBA-mediated carcinogenesis and suggest that PPARgamma may act as a tumor modifier of skin, ovarian and breast cancers. The data also support evidence suggesting a beneficial role for PPARgamma-specific ligands in the chemoprevention of mammary, ovarian and skin carcinogenesis. |
Address |
Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA |
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English |
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Edition |
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ISSN |
0143-3334 |
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Notes |
PMID:15073042 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
76 |
Permanent link to this record |
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Author |
Birch, H.L.; Bailey, A.J.; Goodship, A.E. |
Title |
Macroscopic 'degeneration' of equine superficial digital flexor tendon is accompanied by a change in extracellular matrix composition |
Type |
Journal Article |
Year |
1998 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
Volume |
30 |
Issue |
6 |
Pages |
534-539 |
Keywords |
Animals; Collagen/analysis; DNA/analysis; Extracellular Matrix/*chemistry; Glycosaminoglycans/analysis; Horses/injuries/*physiology; Immunohistochemistry; Rupture/veterinary; Tendon Injuries/metabolism/pathology/veterinary; Tendons/chemistry/*pathology; Water/analysis |
Abstract |
Injuries to the superficial digital flexor tendon are common in horses required to gallop and jump at speed. Partial rupture of this tendon usually occurs in the central core of the midmetacarpal region and may be preceded by localised degenerative changes. Post mortem examination of apparently normal equine flexor tendons has revealed an abnormal macroscopic appearance in the central core, characterised by a reddish discolouration. We have previously shown that there is also physical damage to the collagen fibres. In the present study we tested the hypothesis that the abnormal appearance is accompanied by changes in the composition of the extracellular matrix of the tendon. Biochemical analysis of the extracellular matrix demonstrated an increase in total sulphated glycosaminoglycan content, increase in the proportion of type III collagen and decrease in collagen linked fluorescence in the central core of 'degenerated' tendons relative to tissue from the peripheral region of the same tendon. Dry matter content and total collagen content were not significantly different between tendon zones or normal and 'degenerated' tendons. These changes suggest a change in cell metabolism and matrix turnover in the central core of the tendon and are likely to contribute to a decrease in mechanical properties in this part of the tendon, predisposing to the characteristic partial rupture of the tendon. |
Address |
Veterinary Basic Sciences, Royal Veterinary College, North Mymms, Hatfield, UK |
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English |
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Edition |
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ISSN |
0425-1644 |
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Notes |
PMID:9844973 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3794 |
Permanent link to this record |