Outcome of palmar/plantar digital neurectomy in horses with foot pain evaluated with magnetic resonance imaging: 50 cases (2005-2011).

REASONS FOR PERFORMING STUDY: There is limited knowledge of the foot lesions that influence the outcome of palmar/plantar digital neurectomy (PDN). OBJECTIVES: 1) To report the short- and long-term outcomes of horses that underwent PDN to alleviate chronic foot pain due to lesions diagnosed by magnetic resonance imaging (MRI) and 2) factors that may influence the outcome of PDN. STUDY DESIGN: Multicentre retrospective study. METHODS: Medical records of 50 horses subjected to PDN due to chronic foot pain were reviewed. Age, breed, sex, athletic activity, duration of lameness, affected limb(s), response to anaesthesia of the palmar/plantar digital nerves, MRI findings and surgical technique were analysed together with follow-up data to identify factors that influenced the long-term outcomes. RESULTS: Forty-six of 50 horses (92%) responded positively to surgery; 40 (80%) were able to return to their previous athletic use for a median time of 20 months (range: 12-72 months). Eighteen (36%) horses developed post operative complications including residual lameness, painful neuromas, or early recurrence of lameness. Horses with pre-existing core or linear lesions of the deep digital flexor tendon (DDFT) had significantly shorter periods of lameness resolution after surgery than horses with dorsal border lesions of the DDFT or other foot lesions. CONCLUSIONS: Palmar/plantar digital neurectomy can improve or resolve lameness in horses with foot pain unresponsive to medical therapy without serious post operative complications. However, horses with core or linear lesions of the DDFT should not be subjected to PDN as these horses experience residual lameness or early recurrent lameness after surgery. Magnetic resonance imaging can be used to identify these horses.

Acute phase response of C-reactive protein of Labeo rohita to aquatic pollutants is accompanied by the appearance of distinct molecular forms.

Different forms of C-reactive proteins have been purified to electrophoretic homogeneity by calcium dependent affinity chromatography on a phosphorylcholine (PC)-Sepharose column from the sera of Labeo rohita confined in fresh water (CRP(N)) and water polluted with sublethal doses of cadmium (CRP(Cd)), mercury (CRP(Hg)), phenol (CRP(Ph)), and hexachlorocyclohexane (CRP(Hx)), which elevate serum CRP levels by three- to fivefold. On native PAGE, induced forms of CRP show remarkable differences in their electrophoteric mobility indicating differences in molecular mass, charge, and/or shape. Kinetic studies reveal the appearance of a pollutant specific molecular variant, which replaces the normal form at the peak of induction. Studies on amino acid and carbohydrate compositions, isoelectric focusing, binding to PC, C-polysaccharide (CPS) & lectins, and secondary structures of the purified CRPs, indicate, that, they differ significantly from each other, but grossly share the common properties of a CRP, including pentraxin, structure revealed by electron microscopy.

Glycosylated molecular variants of C-reactive proteins from the major carp Catla catla in fresh and polluted aquatic environments.

Elevated level of pollutant specific glycosylated molecular variants of C-reactive protein have been purified to electrophoretic homogeneity from the sera of major carp, Catla catla confined in freshwater (CRP(N)) and water polluted with nonlethal doses of cadmium (CRP(Cd)), mercury (CRP(Hg)), phenol (CRP(Ph)) and hexachlorocyclohexane (CRP(Hex)). These CRPs differ amongst themselves in electrophoretic mobility, and in their carbohydrate content ranging from 20-50%. CRPs interact with pneumococcal C-polysaccharide (CPS) showing different binding constants. Both phosphorylcholine (PC) and calcium are indispensable for binding. Studies on amino acid compositions, electrophoretic analysis, isoelectric focusing, binding to PC & CPS and secondary structures of the purified CRPs indicate, that, they differ from each other. However, they share the common properties of a CRP, including pentraxin structure revealed by electron microscopy. Taken together, our results provide a new structural insight regarding the connection between the presence of unique molecular variants and probably the toxicity therein combated.

Structural characterisation of the native fetuin-binding protein Scilla campanulata agglutinin: a novel two-domain lectin.

The three-dimensional structure of a 244-residue, multivalent, fetuin-binding lectin, SCAfet, isolated from bluebell (Scilla campanulata) bulbs, has been solved at 3.3 A resolution by molecular replacement using the coordinates of the 119-residue, mannose-binding lectin, SCAman, also from bluebell bulbs. Unlike most monocot mannose-binding lectins, such as Galanthus nivalis agglutinin from snowdrop bulbs, which fold into a single domain, SCAfet contains two domains with approximately 55% sequence identity, joined by a linker peptide. Both domains are made up of a 12-stranded beta-prism II fold, with three putative carbohydrate-binding sites, one on each subdomain. SCAfet binds to the complex saccharides of various animal glycoproteins but not to simple sugars.

Structure of the native (unligated) mannose-specific bulb lectin from Scilla campanulata (bluebell) at 1.7 A resolution.

The X-ray crystal structure of native Scilla campanulata agglutinin, a mannose-specific lectin from bluebell bulbs and a member of the Liliaceae family, has been determined by molecular replacement and refined to an R value of 0.186 at 1.7 A resolution. The lectin crystallizes in space group P21212 with unit-cell parameters a = 70. 42, b = 92.95, c = 46.64 A. The unit cell contains eight protein molecules of Mr = 13143 Da (119 amino-acid residues). The asymmetric unit comprises two chemically identical molecules, A and B, related by a non-crystallographic twofold axis perpendicular to c. This dimer further associates by crystallographic twofold symmetry to form a tetramer. The fold of the polypeptide backbone closely resembles that found in the lectins from Galanthus nivalis (snowdrop) and Hippeastrum (amaryllis) and contains a threefold symmetric beta-prism made up of three antiparallel four-stranded beta-sheets. Each of the four-stranded beta-sheets (I, II and III) possesses a potential saccharide-binding site containing conserved residues; however, site II has two mutations relative to sites I and III which may prevent ligation at this site. Our study provides the first accurate and detailed description of a native (unligated) structure from this superfamily of mannose-specific bulb lectins and will allow comparisons with a number of lectin-saccharide complexes which have already been determined or are currently under investigation.

Isolation, characterization, molecular cloning and molecular modelling of two lectins of different specificities from bluebell (Scilla campanulata) bulbs.

Two lectins have been isolated from bluebell (Scilla campanulata) bulbs. From their isolation by affinity chromatography, they are characterized as a mannose-binding lectin (SCAman) and a fetuin-binding lectin (SCAfet). SCAman preferentially binds oligosaccharides with alpha(1,3)- and alpha(1,6)-linked mannopyranosides. It is a tetramer of four identical protomers of approx. 13 kDa containing 119 amino acid residues; it is not glycosylated. The fetuin-binding lectin (SCAfet), which is not inhibited by any simple sugars, is also unglycosylated. It is a tetramer of four identical subunits of approx. 28 kDa containing 244 residues. Each 28 kDa subunit is composed of two 14 kDa domains. Both lectins have been cloned from a cDNA library and sequenced. X-ray crystallographic analysis and molecular modelling studies have demonstrated close relationships in sequence and structure between these lectins and other monocot mannose-binding lectins. A refined model of the molecular evolution of the monocot mannose-binding lectins is proposed.

Crystallization and preliminary structural studies of Scilla campanulata lectin complexed with alpha1-6 mannobiose.

Recent work has shown that Scilla campanulata agglutinin from bluebell bulbs has a strong affinity for alpha(1,3)- and alpha(1,6)-linked mannosyl residues and possesses moderate antiretroviral activity. This lectin has been crystallized by the hanging-drop method of vapour diffusion complexed with the disaccharide mannose-alpha1,6-D-mannose. The crystals are in the space group P21212 with unit-cell dimensions a = 70.63, b = 92.79 and c = 47.25 A, and with a dimer in the asymmetric unit. The crystals diffract X-rays to beyond 1.5 A resolution at 277 K and are stable in an X-ray beam. Data to 1.6 A resolution have been collected using a MAR image-plate system at a synchrotron source and the structure of the complex has been solved by the molecular replacement method.

Purification and characterization of a 93 kDa Aspergillus fumigatus antigen with diagnostic potential.

A glycoprotein with an apparent molecular weight of 93 kDa was purified from a water-soluble extract of Aspergillus fumigatus NCPF 2109 by single step affinity chromatography using the mannose-specific snowdrop (Galanthus nivalis) lectin coupled to agarose. The carbohydrate moiety contained only mannose and galactose. Partial sequencing of cyanogen bromide fragments of the antigen yielded two sequences, KQNKP and GEIPMKF?PQL, with no homology to any reported proteins. In a preliminary evaluation of its diagnostic potential the 93 kDa antigen was recognized by the sera of four patients with allergic bronchopulmonary aspergillosis, in addition to a monoclonal antibody raised against a partially purified fraction of the A. fumigatus water-soluble extract.

Potato lectin: a three-domain glycoprotein with novel hydroxyproline-containing sequences and sequence similarities to wheat-germ agglutinin.

Potato (Solanum tuberosum) tuber lectin is a chitin-binding, hydroxyproline-rich glycoprotein, which may be involved in the defence mechanism of the plant. We had previously obtained evidence that it consists of at least two very dissimilar domains. The aim was to use a combination of accurate determinations of molecular weight and protein sequencing to gain more accurate information on the domains. Accurate determinations of the molecular weight of the lectin by a MALDI mass spectrometer have shown that the subunit molecular weight is 65,500 (+/- 1100) and that of a totally deglycosylated sample is 31,250 (+/- 30). This means that the lectin is 52.3 (+/- 1)% carbohydrate with a considerable number of glycoforms being present. Partial sequences and other analyses are consistent with the existence of three distinct domains. These are: (1) an N-terminal region which is rich in proline but poor in hydroxyproline; (2) a glycosylated region with a glycosylated molecular weight of 45,300 (+/- 1100) and a deglycosylated molecular weight of 11,050 (+/- 50) which is extremely rich in glycosylated hydroxyproline residues with a similar sequence to extensins; and (3) a cystine-rich domain which has the sugar binding site shows partial conservation of a repeated motif common to many chitin-binding proteins of the hevin family including wheat-germ agglutinin. The closest similarity seems to be to the sequence of potato basic chitinase.

Purification, crystallization and preliminary X-ray analysis of a mannose-binding lectin from bluebell (Scilla campanulata) bulbs.

Crystals have been grown of a mannose-specific lectin from bluebell (Scilla campanulata) bulbs in a form suitable for X-ray diffraction studies. The crystals, which diffract to high resolution, grew in hanging drops by vapour diffusion, equilibrating with a solution of 70% saturated ammonium sulfate at pH 4.7-4.8 at 293 K, in the absence of any mannose saccharides. Crystals are orthorhombic, P2(1)2(1)2, with unit-cell dimensions a = 70.78, b = 93.69, c = 46.92 A. The functional lectin molecule is organized as a tetramer of four identical 14 kDa subunits, with only two subunits in the asymmetric unit. Data to 1.86 A resolution have been recorded and the structure determined by the molecular replacement method.

Acid:base and serum biochemistry changes in horses competing at a modified 1 Star 3-day-event.

We examined the effects of participation in each of 3 modifications of Day 2 of a 3-day-event on blood and serum variables indicative of hydration, acid:base status and electrolyte homeostasis of horses. Three groups of horses - 8 European (E) horses and 2 groups each of 9 North American horses performed identical Days 1 (dressage) and 3 (stadium jumping) of a 3-day-event. E horses and one group of the North American horses (TD) performed modifications of Day 2 of a 1 Star 3-day-event and the other group of North American horses (HT) performed a Horse Trial on Day 2. Jugular venous blood was collected from each horse on the morning of Day 2 before any warm-up activity, between 4 min 55 s and 5 min 15 s after Phase D and the following morning. Eight E horses, 5 TD horses and 8 HT horses completed the trials. There were few significant differences in acid:base or serum biochemistry variables detected among horses performing either 2 variations of the Speed and Endurance day of a 1 Star 3-day-event, or a conventional Horse Trial. Failure to detect differences among groups may have been related to the low statistical power associated with the small number of horses, especially in the TD group, variation in quality of horses among groups and the different times of the day at which the E horses competed. Differences detected among time points were usually common to all groups and demonstrated metabolic acidosis with a compensatory respiratory alkalosis, a reduction in total body water and cation content, and hypocalcaemia. Importantly, horses of all groups did not replenish cation, chloride, and calcium deficits after 14-18 h of recovery.

Physiological responses of horses competing at a modified 1 star 3-day-event.

The impending 1996 summer Olympic 3-day-event in Atlanta has focused attention on the need to determine what modifications to the demanding Endurance Test will be required to ensure safety of the horses competing. Three groups of horses participated in a Field Trial held in August of 1994 in northern Georgia to determine the safety and feasibility of conducting a modified 3-day-event in hot, humid weather. One group (TD) completed a modified 1 Star 3-day-event test, a control group (HT) completed a Horse Trial identical to the modified 1 Star test except for the omission of Phases B and C and the third group (E), comprised of European horses, completed the modified 1 Star test with a longer, faster Phase C than was used for TD. During the Endurance Test, the ambient temperature and relative humidity ranged from 24.3 degrees C and 98.9% in the morning to 30.2 degrees C and 51.6% in the afternoon. No horse failed to complete the Trial because of heat stress or fatigue. There were no significant (P < 0.05) differences detected in heart rate, rectal temperature, respiratory rate or net weight loss between HT and TD horses at any observation time. The highest rectal temperature recorded at the end of Phase C was 39.6 degrees C. These findings suggest that the modified 1 Star Endurance Test was as well tolerated by American horses as the control Horse Trial test. Rectal temperature was significantly higher for E than for TD or HT at the finish of Phase C. European horses had significantly greater decreases in weight than HT and TD at the end of Phases C and D and the next day. These findings probably reflect the faster and longer work effort of E horses during Phase C. Modification of Phase C and the rest-pause to ensure that recovery and heat dissipation occurred before the start of Phase D resulted in a 3-day-event that was safe for horses. The Field Trial provides a model for designing a modified Olympic Endurance Test. If the 1996 Olympic 3-day-event is held in hotter and more humid weather than the Field Trial, additional modifications to the Endurance Test (decreased distances, speeds and numbers of jumping efforts) will probably be required to ensure safety of competing horses.

Purification and characterization of an N-acetyllactosamine-specific lectin from tubers of Arum maculatum.

A lectin was purified from the tubers of Arum maculatum (family Araceae) by affinity chromatography on a thyroglobulin-Sepharose column. The lectin is not a glycoprotein and has a subunit molecular weight of 14,600. It is specifically inhibited by N-acetyllactosamine (Gal beta 1,4GlcNAc), but is not significantly inhibited by monosaccharides or by lactose (Gal beta 1,4Glc), lacto-N-biose 1 (Gal beta 1,3GlcNAc), or chitobiose (GlcNAc beta 1,4GlcNAc). Asialoglycoproteins which contain N-acetyllactosamine structures are even more effective inhibitors of the lectin. This lectin should be a useful probe for N-acetyllactosamine groups in glycoproteins.

Influence of widow inheritance on the epidemiology of AIDS in Africa.

PIP: The deeply rooted tradition of widow inheritance is a determinant of sex among the Luo which is widely practiced by Luo groups in Uganda, Tanzania, Zaire, and Sudan. This practice of sexual networking whereby men who inherit widows have multiple sex partners, high frequency of exchange between widows, and low levels of condom use, however, encourages the spread of HIV. The authors interviewed 92 widows of mean age 34 years to investigate this traditional behavior among the Luo in South Nyanza District, Kenya. Subjects were widows of Luo men who had died of a chronic illness between November 1991 and October 1992. 47 had already been inherited and 34 were planning to be, while 11 refused to be inherited for fear of spreading HIV. Of the men who inherited them, 80% were married, one third had histories of inheriting other widows, and some were paid to take on their new responsibilities. Only two widows reported ever using condoms since the demise of their spouse even though sexual intercourse is an essential component of widow inheritance. The lack of condom use corresponds with the lack of knowledge about the ability of condoms to prevent the spread of HIV; only 9% reported being aware of this condom attribute. 87% of the widows, however, reported that sexual intercourse with multiple partners can lead to the transmission of HIV. 70% felt that monogamy and avoiding prostitutes can prevent the spread of HIV. These findings point to the urgent need for community based AIDS education targeting elders, women, and youth.^ieng

Crystallization and preliminary X-ray studies on the mannose-specific lectin from Amaryllis bulbs.

Affinity-purified amaryllis lectin was used to grow single crystals using the hanging-drop method. The space group was found to be C2 with unit-cell dimensions a = 73.4 (1), b = 100.3 (1), c = 62.2 (1) A and beta = 137.3 (2) degrees. Data to 2.25 A resolution have been recorded and solution of the structure is currently underway by means of molecular-replacement techniques.

Influence of widow inheritance on the epidemiology of AIDS in Africa

The objective of this text is to investigate traditional behavior practices that could influence the transmission of Human Immunodeficiency Virus among the Luo of Kenya. The subjects were widows of Luo men who had died of a chronic illness between November 1991 and October; 1992. It is concluded that widow inheritance is a determinant of sex among the Luo and influences the spread of HIV due to the pattern of sexual networking whereby men who inherit widows have multiple sex partners; high frequency of exchange of these men among widows and low level of condom use. Considering that this practice is deeply rooted; and is practised by Luo groups in Uganda; Tanzania; Zaire and Sudan; community based AIDS education targeting the elders; women and the youth should be started with the aim of finding a solution of the AIDS pandemic

The carbohydrate structures of Trypanosoma brucei brucei MITat 1.6 variant surface glycoprotein. A re-investigation of the C-terminal glycan.

We have studied the oligosaccharide chains of the variant surface glycoprotein (VSG) of Trypanosoma brucei brucei MITat 1.6. Glycopeptides were generated by Pronase digestion, purified by gel permeation and ion-exchange chromatography, and structurally characterized by 1H and 31P NMR spectroscopy in combination with chemical composition analyses. The two glycopeptide fractions obtained each proved to be homogeneous in their peptide and heterogeneous in their carbohydrate structures. The fraction representing the "internal" N-glycosylation site of the VSG was found to contain high-mannose type oligosaccharides with structures Man7-9GlcNAc2 linked to Asn-Ala-Thr. The other glycopeptide fraction contained the membrane-anchoring C-terminal glycan of the VSG attached to Asp. Its oligosaccharide structures are of the glycosylphosphatidylinositol (GPI) type: [structure: see text] This structure includes revisions of multiple structural features published for the GPI anchor of T. b. brucei MITat 1.6 VSG by Schmitz et al. (1987) Biochem. Biophys. Res. Commun. 146: 1055-1063.