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Injections of quinolinic acid (60, 180, and 600 nmol) in the dorsal hippocampus induced significant neurotoxicity that was evident 1 day after the injection. By day 3, pyramidal as well as granular cells were affected even at the lowest dose of quinolinic acid, an effect that persisted up to 20 days. Consistent with the histological findings, animals with bilateral injections in the dorsal hippocampus were cognitively impaired during acquisition and retention of spatial information in the water maze. A subacute treatment with (-)-nicotine (62 micromol/kg/day) delivered by subcutaneous minipumps prevented the histological and cognitive deficits induced by the bilateral quinolinic acid (60 nmol) injections. These data indicate that quinolinic acid can induce degeneration of both pyramidal as well as granule cells in the hippocampus, leading to cognitive impairments in the rat, and that activation of neuronal nicotinic acetylcholine receptors can prevent the neurodegenerative process induced by quinolinic acid., (Copyright 1998 Academic Press.)

CC chemokine receptor 2 (CCR2) is a prominent receptor for the monocyte chemoattractant protein (MCP) group of CC chemokines. Mice generated by gene targeting to lack CCR2 exhibit normal leukocyte rolling but have a pronounced defect in MCP-1-induced leukocyte firm adhesion to microvascular endothelium and reduced leukocyte extravasation. Constitutive macrophage trafficking into the peritoneal cavity was not significantly different between CCR2-deficient and wild-type mice. However, after intraperitoneal thioglycollate injection, the number of peritoneal macrophages in CCR2-deficient mice did not rise above basal levels, whereas in wild-type mice the number of macrophages at 36 h was approximately 3.5 times the basal level. The CCR2-deficient mice showed enhanced early accumulation and delayed clearance of neutrophils and eosinophils. However, by 5 days neutrophils and eosinophils in both CCR2-deficient and wild-type mice had returned to near basal levels, indicating that resolution of this inflammatory response can occur in the absence of macrophage influx and CCR2-mediated activation of the resident peritoneal macrophages. After intravenous injection with yeast beta-glucan, wild-type mice formed numerous large, well-defined granulomas throughout the liver parenchyma, whereas CCR2-deficient mice had much fewer and smaller granulomas. These results demonstrate that CCR2 is a major regulator of induced macrophage trafficking in vivo.

The pathologic changes in articular cartilage appear to be of central importance in the development of canine hip dysplasia. But, articular cartilage has only a limited number of responses to injury and a limited capacity for repair. Damage to articular cartilage in dogs with canine hip dysplasia is likely multifactorial in origin, involving cytokines, abnormal load-bearing, and, possibly, other undefined factors.

Inter-observer and intra-observer reliability for classifying radial head fractures by the system of Mason was analyzed. Twenty-three cases of isolated radial head fractures and twenty-five sets of corresponding AP and lateral radiographs representing these fractures were assembled. The cases were reviewed and assessed independently according to the system of Mason by twenty practicing orthopedic surgeons. On two occasions, the inter-observer and intra-observer variation was analyzed by standard unweighted Kappa statistics. In both observations, complete agreement was seen in only 16% of the cases. Kappa statistic values indicated that 69% of the cases at first observation and 45% of the cases at second observation suggest moderate to poor agreement. Intra-observer agreement between the first and second observation was graded fair to poor in 60% of the cases. Individual observer consistency was, on average, only 78% (range 60% to 92%). The demonstrated wide degree of variation suggests that the Mason classification is unreliable.

Thrombus formation within artificial organs has been shown, at least in part, to be caused by retarded or stagnant blood flow. The goal of this work was to develop a magnifying fiber optic probe capable of visualizing particle flow and cellular deposition in a physiologically relevant cellular suspension (blood). The probe has minimal cross sectional area to allow for access to confined areas and to minimize flow disturbance. The probe consists of a germanium oxide fiber optic bundle and a gradient index imaging lens. Fluorescent microspheres of 48 microns, 7 microns, and 3 microns in diameter were imaged after deposition on to a cover slip. The flow (1.44 mm/sec) of 3 microns microspheres suspended in buffer alone and with red cell hematocrits of 10%, 25% and 45% were also visualized. To investigate the potential for this probe to detect ongoing thrombosis, fluorescently labeled human platelets were observed depositing on surfaces from a stagnant platelet rich buffer. These initial data suggest that this probe may offer a technique for the visualization of blood cell adhesion on the interior of artificial organs and the local quantification of flow in such devices.

To answer the question, "How toxic is this material?", rather than the question more usually asked in in vitro toxicology, "At what concentration does this material produce a given degree of toxicity?", a fixed-dose approach has been developed with the FRAME fluorescein leakage (FL) test. Recovery from the initial cytotoxic effect was also noted sometimes, after the cells had been maintained in fresh medium for a further 72 hr. Chemicals rated R41 or R36 in vivo gave a level of FL above 20% immediately, and 66% or more 72 hr later (i.e. there was further deterioration, rather than recovery). Acetaldehyde, when duplicated and tested either in Hanks' balanced salt solution or oil, showed greater toxicity in the oil because of its high volatility. The chemicals classified as no-label gave FL values below 12% immediately after exposure, except Brij-35, which showed no further deterioration during the 72-hr period in fresh medium.

Receptor-linked phosphatidylinositol (PtdIns) 3-kinase may generate a second-messenger signal. Here a large-scale purification of the bovine brain enzyme, based on methods developed by Morgan, Smith and Parker [(1990) Eur. J. Biochem. 191, 761-767] and Fry, Panayotou, Dhand, Ruiz-Larrea, Gout, Nguyen, Courtneidge and Waterfield [(1992) Biochem. J. 288, 383-393] is described. The purified enzyme is shown to be a heterodimer of 85 kDa and 110 kDa protein subunits (p85 and p110). Labelling with 5'-p-fluorosulphonylbenzoyladenosine shows that p110 contains an ATP-binding site and confers catalytic activity to the complex. The purified complex is known to be highly phosphorylated on both p85 alpha and p110 subunits, and dephosphorylation generates a deactivated complex, indicating that phosphorylation is an important covalent modification of the complex and may modulate PtdIns 3-kinase activity.

The relative toxicity of phenylbutazone, flunixin meglumine, and ketoprofen was studied in healthy adult horses. Sixteen horses were randomly assigned to receive 10 ml of physiologic saline solution, or ketoprofen (2.2 mg/kg of body weight), flunixin meglumine (1.1 mg/kg), or phenylbutazone (4.4 mg/kg) IV, every 8 hours, for 12 days. Results of CBC, serum biochemical analyses, and fecal occult blood tests were monitored. On day 13, all horses were euthanatized and complete necropsy examinations were performed. Mean CBC values remained within normal limits for all groups. Phenylbutazone-treated horses had a significant (P < 0.05) decrease in serum total protein and albumin concentrations. Mean values of all other serum biochemical assays were not different from those of the saline-treated group. Results of all fecal occult blood tests were negative. At necropsy, the glandular portion of the stomach was the area of the gastrointestinal tract most severely affected by phenylbutazone, flunixin meglumine, and ketoprofen. In the phenylbutazone-treated group, but not in the other groups, edema of the small intestine and erosions and ulcers of the large colon were observed. None of the horses treated with saline solution had lesions in the glandular portion of the stomach or in the intestine. Four horses (1/5 and 3/3 in the flunixin- and phenylbutazone-treated groups, respectively) developed renal crest necrosis. Horses in the saline- and ketoprofen-treated groups did not develop renal lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Three hundred consecutive cases of radial keratotomy performed between 1985 and 1990 were reviewed. There were no sight threatening complications of surgery and no patient lost one or more lines of corrected Snellen acuity. Overall 78.7% saw 6/12 or better unaided postoperatively and 51.7% saw 6/6 or better. Refraction showed 61.3% to be within 1 dioptre of emmetropia and 86.7% were within 2 dioptres. Further analysis demonstrated that results of unaided acuity and proximity to emmetropia were much better for low (< -2.87 D) and moderate (-3.0 to -5.87 D) than for high (> -6.0 D) myopes.

Although the complete pathogenesis of cartilage damage in canine hip dysplasia has not been completely worked out, it appears that joint laxity with resultant excessive stresses upon articular cartilage is the initiating factor. Grossly, this damage is characterized by cartilage thinning with potential exposure of subchondral bone, osteophyte formation, and pannus formation. Microscopically, there is a marked variation in chondrocyte cellularity, with focal regions of hypocellularity and chondrocyte clusters and synovial lining cell hyperplasia and hypertrophy as well as a decrease in proteoglycan content. This latter change has been substantiated biomechanically. Ultrastructural studies indicate that there is extensive alteration of collagen organization within the cartilage.

Healing of transected superficial digital flexor tendons was evaluated mechanically and histologically in eight horses. Tendons sutured with polyglyconate had higher loads at failure than nonsutured tendons at weeks 5 and 9. The tendon stress at failure (force per unit area) was higher in the sutured tendons at week 5 but not at week 9, reflecting the increased size of the scar at week 9. Histologically, scars after tenorrhaphy were consistently more mature than nonsutured tenotomy scars. The mean maturity score for sutured tendons was higher than for nonsutured tendons at weeks 5 and 9. Overall, these data support tenorrhaphy with absorbable suture.

Histological and morphometric evaluation of equine cranial mesenteric arteries was performed on 239 and 89 arteries, respectively. Histological examination revealed that thrombosis and the severity of inflammation varied on a seasonal basis and were directly associated with larval presence. Intimal and adventitial fibrosis were generally of greater severity than medial fibrosis. Fibrosis of the vasa vasorum was less frequent than fibrosis of the artery itself. Morphometry revealed a significant increase in intimal, adventitial and, to a lesser extent, medial area in affected as compared with normal arteries. This change was due to the accumulation of collagen and was considered to result in decreased arterial elasticity. The luminal area varied widely among affected arteries.

In this study we report the numbers and metachromatic dye-staining characteristics of mast cells (MCs) in the conjunctiva of normal subjects and patients with seasonal allergic conjunctivitis caused by pollenosis. In addition, we have used a monoclonal antibody to the MC-specific enzyme, tryptase, to enumerate tryptase-positive cells immunohistochemically. Tarsal conjunctival MCs were found to be present in increased numbers in the allergic compared to the nonallergic subjects. Most of the MCs exhibited staining that was formaldehyde resistant, compatible with their identification as connective tissue MCs or basophils. The high positive staining for tryptase confirmed that the metachromatic cells stained with toluidine blue were MCs and not basophils, both in normal and allergic subjects.

Immunohistochemical staining of conjunctival biopsies from four normal subjects and five patients with atopic keratoconjunctivitis (AKC) was performed, using a monoclonal antibody to human mast cell tryptase. A massive hyperplasia of mast cells in the patients with AKC was demonstrated. The mean mast cell density in the normal patients was 55.6/mm2 and in the patients with AKC, 172/mm2. The appearance of large numbers of mast cells in the conjunctival epithelium of AKC patients was also demonstrated. The possible pathophysiological significance of these findings is discussed.

The cholestanol content of a cataractous lens nucleus from a patient with cerebrotendinous xanthomatosis (CTX) was quantified by gas chromatography-mass spectrometry and found to be 0.27 micrograms per mg freeze-dried lens tissue. The cholestanol-cholesterol ratio of 1.7% in the lens nucleus was similar to that in the serum of the CTX patient. The cholestanol content and cholestanol-cholesterol ratio in the CTX lens were approximately four-fold and six-fold greater respectively than the mean levels found in three senile cataractous lens nuclei analysed simultaneously for comparative purposes.

Investigation into the phosphatidylinositol kinase activities in bovine brain has revealed the presence of a type I PtdIns kinase activity. This classification is based upon potent inhibition by neutral detergent and the production of a phosphatidylinositol phosphate that can be distinguished from phosphatidyl-inositol-4-phosphate [PtdIns(4)P] by thin-layer chromatography. The enzyme has been substantially purified and the activity is associated with an 85-kDa polypeptide on SDS/polyacrylamide gel electrophoresis. Analysis of the product confirms the identification of the enzyme as a type I PtdIns kinase. The purified kinase has been characterized with respect to substrate dependence (Mg2+, ATP, PtdIns), substrate presentation (pure lipid versus mixed micelle) and specificity [PtdIns versus PtdIns(4)P and phosphatidylinositol 4,5-bisphosphate].

Cells found in the intima and media of the cranial mesenteric artery of a mature mare with chronic arteritis were identified as smooth muscle cells and occurred in association with collagen and elastin fibres. As no fibroblasts were demonstrable within these regions, the smooth muscle cells were the likely source of the extracellular matrix. In contrast, the abnormal adventitis from the same artery contained abundant fibroblasts which are considered to be the source of the adventitial collagen.

The effect of pulsing electromagnetic field (PEMF) therapy on the healing of surgically created defects in equine superficial digital flexor tendons was evaluated. Defects were created in both front superficial digital flexor tendons of 20 horses. The defect in 1 limb was exposed to a PEMF for 2 hours daily. The other limb served as a control. Histologic and immunofluorescent evaluations were done in horse killed at postsurgical weeks 2, 4, 8, 12, and 24. Therapy with the PEMF significantly (P less than 0.05) delayed the maturation of the tissue formed within the defect at postsurgical weeks 8 and 12, as determined by histologic examination. The collagen-type transformation was also delayed by the PEMF therapy, but to a degree that was not significant.

Y strain parasites (Wellcome stock) were cloned as epimastigotes by limiting dilution and one clone, Wel Tryp A2 was used to infect cell cultures and irradiated mice. The fibrosarcoma line, M4, was susceptible to infection with Wel Tryp A2 trypomastigotes but, after the first round of intracellular infection, proliferation and differentiation, failed to support parasite growth in long-term continuous culture. In contrast, a muscle-derived cell line, S2, produced regular waves of extracellular trypomastigotes and amastigotes during 80 days of continuous culture reported here. These infected S2 cultures have remained in continuous culture for up to 18 months over a 5-year period and have yielded in excess of 10(8) parasites/20 ml culture at 4-6 day intervals. Extracellular amastigotes produced in these cultures have a close morphological, immunological and biochemical analogy to intracellular parasites derived from rodents, and have maintained an absolute dependence on host cells for their growth and proliferation. These amastigotes produced low-grade chronic infections in normal CBA/T6 mice but produced acute, fatal infections with high parasitaemia in mice of the same inbred strain given 900 rad. whole-body irradiation prior to infection. Although present findings relate to a single parasite clone, the parent stock from which the clone was derived showed similar growth characteristics when co-cultured with S2 cells.

1. When added to cultures of human peripheral lymphocytes, saturated (palmitate, stearate, heptadecanoate) and unsaturated (oleate, linoleate, arachidonate) fatty acids bound to albumin at an acid-albumin ratio of 2:1, inhibited the phytohaemaegglutinin-stimulated uptake of [14C]-uridine. Uridine uptake in unstimulated cells was not affected by any of these fatty acids. 2. When saturated and unsaturated acids were present simultaneously in the incubation mixture the inhibit but relieved the inhibitory effects of both saturated and unsaturated fatty acids. 4. Stimulated and unstimulated cells incorporated exogenous fatty acids into membrane phosphoglycerides. Details of the fatty acid profiles are given. 5. Evidence is presented that the inhibition results, at least in part, from modification of phosphoglyceride fatty acid profile.

For the 14 months 1 January 1985 to 28 February 1986 all cases of chemical eye injury presenting to the Croydon Eye Unit were analysed. Of the 180 cases 19 were caused by assaults and 14 were admitted for treatment. The wide range of injurious substances is emphasised, and the circumstances of injury are listed. A discussion of the management of chemical eye injury is included.

Factors involved in the proliferation of equine vascular smooth muscle cells were studied in vitro. The most prominent proliferative responses in cultured vascular smooth muscle cells were induced by Strongylus vulgaris larval antigen extract (LAE) and platelet-derived factors. Less significant proliferative responses were obtained with conditioned media from S. vulgaris LAE stimulated and from unstimulated equine mononuclear leukocytes. Additionally, vascular smooth muscle cells exposed to S. vulgaris LAE developed numerous perinuclear vacuoles and were more spindle-shaped than control or smooth muscle cells exposed to other factors. Equine mononuclear leukocytes exposed to LAE developed prominent morphological changes, including enlargement, clumping and increased numbers of mitotic figures.

A case of cerebrotendinous xanthomatosis is reported. In addition to the classical ophthalmic and systemic features the patient presented with unilateral proptosis. This feature has never previously been reported. The results of investigations are described and illustrated.

Epidermal growth factor (EGF) receptor binding kinetics and EGF-mediated stimulation of DNA synthesis and cellular proliferation were studied in cultured vascular smooth muscle cells (VSMC) from the equine thoracic aorta. Binding studies, using murine 125I-labeled EGF, indicate the presence of a single class of high-affinity binding sites (apparent KD = 2.8 X 10(-11) M), with an estimated maximal binding capacity of 5,800 sites/cell. EGF stimulated [3H]thymidine uptake in confluent quiescent monolayers in a dose-dependent fashion, half-maximal stimulation occurring at 7.5 X 10(-11) M. Likewise, EGF-mediated cellular proliferation was dose dependent (50% effective dose = 5 X 10(-11) M) under reduced serum concentrations. Equine VSMC contain specific receptors for EGF, and EGF can stimulate DNA synthesis and proliferation in these cultured cells, which suggests that EGF may participate in the proliferative changes observed in equine distal digital peripheral vascular disease.

A 2-year-old Quarter Horse gelding was examined for torticollis, facial protuberances over the frontal and maxillary sinuses, and persistent nasal discharge unresponsive to antibiotics. Radiograph revealed an osseous mass in the right paranasal sinuses. Histologic examination of the biopsied mass led to a diagnosis of osteoma. The mass was removed surgically in sections from the right frontal and maxillary sinuses through separate bone flaps, and sinuses were irrigated with saline solution for 8 days after surgery. Two weeks after surgery, radiography revealed small osseous opacities in the right paranasal sinuses. These opacities remained unchanged in radiographs obtained up to 23 months after surgery.

Full-thickness defects were surgically created in the superficial digital flexor tendons of the front limbs of 20 horses. Tissues formed within the defect were evaluated histologically, and the collagen composition of the tissue was determined by immunofluorescence. Transformation occurred from loose fibrillar areas of types I and III collagen and pericellular types IV and V collagen to dense bundles of type I collagen fibers. Loose fibrillar areas of types I and III collagen were present after 24 weeks. Histologically, in horses killed after 2 weeks, the tissue within the defect was a randomly oriented mass of fibrovascular tissue. In horses killed after 24 weeks the tissue within the defect resembled normal tendon tissue.

Differential immunodiagnosis of T. rangeli and T. cruzi infections in man poses a particular problem, not only because these parasites share antigenic determinants, as detected by immunofluorescence, but also because they have a similar geographical distribution, the same host range and often identical insect vectors. We show here that whereas mouse anti-T. rangeli sera have significant cross reactivity with T. cruzi by immunofluorescence, they are entirely specific when tested by ELISA, using apparently similar antigen preparations. Immunoprecipitation analysis detected relatively little cross-reactivity between heterologous antisera and parasite combinations. Intriguingly, immunization with T. rangeli epimastigotes was much more powerful than similar immunization with trypomastigotes, and the majority of the antibody was directed against a single polypeptide of apparent Mr 73kDa.