Signaling pathways for tissue factor expression in lipopolysaccharide-stimulated bovine alveolar macrophages.

OBJECTIVE: To investigate receptor-mediated intracellular events in bovine alveolar macrophages (AM) stimulated by bacterial lipopolysaccharide (LPS), using tissue factor (TF) expression as the measurable functional endpoint. SAMPLE POPULATION: Pulmonary AM harvested from 1- to 4-month-old male Holstein calves. PROCEDURE: Alveolar macrophages, acquired by use of volume-controlled bronchopulmonary lavage, were treated with CD14 monoclonal antibody (20 microg/ml), pertussis toxin (300 ng/ml), or 1 of 3 known protein kinase C (PKC) inhibitors (10 microM chelerythrin, 100 microM H-7, or 50 nM staurosporin), then were stimulated with LPS alone (0.01, 0.10, 1.0, 10.0 microg/ml) or LPS (0.25, 0.5, 1.0 ng/ml) in combination with concentrated bovine serum fraction 2 (500 ng/ml). Tissue factor expression was quantified by use of a colorimetric assay. Changes in intracellular Ca2+ concentration and pH were monitored, using Ca2+- and pH-sensitive fluorescent dyes, with changes in fluorescent intensity after incubation with LPS measured by spectrophotometry. RESULTS: Treatment of AM with a CD14 monoclonal antibody caused profound inhibition of TF expression (P < 0.0001) after stimulation by LPS combined with bovine serum fraction 2. Pertussis toxin had a significant (P < 0.0319) inhibitory effect on TF expression when cells were stimulated by LPS alone. Treatment with all 3 PKC inhibitors caused marked reduction in TF expression of cells stimulated with LPS alone or with phorbol myristate acetate. Stimulation of cells by LPS failed to mobilize intracellular Ca2+ stores or to alter cytosolic pH. CONCLUSION: LPS combined with serum factors binds to CD14 on the surface of AM, and PKC is an important signaling kinase in the pathway utilized by LPS, resulting in enhanced TF expression; a pertussis toxin-sensitive G protein is involved in the signaling pathway utilized by LPS alone; and mobilization of Ca2+ does not have a role in the signal transduction pathway utilized by LPS nor does LPS affect cytosolic pH of AM.

Attempt to pharmacologically modulate procoagulant activity of lipopolysaccharide-stimulated adherent bovine alveolar macrophages.

OBJECTIVE: To investigate the effects of anti-inflammatory drugs on lipopolysaccharide-induced procoagulant activity of bovine alveolar macrophages. DESIGN: Procoagulant activity was induced in bovine alveolar macrophages from 4 healthy Holstein calves aged 6 to 16 weeks by incubation with lipopolysaccharide. 3 anti-inflammatory drugs were used at 4 concentrations and 3 times to pretreat the alveolar macrophages. Results were analyzed to determine whether drug, concentration, or exposure period had a significant (P > 0.05) effect. PROCEDURE: Bovine alveolar macrophages, harvested by volume-controlled bronchoalveolar lavage, were pretreated for 30, 60, or 120 minutes with an anti-inflammatory compound (dexamethasone, flunixin meglumine, or phenylbutazone) at several concentrations ( 0, 1, 10, and 100 microM). Bovine alveolar macrophages were exposed to lipopolysaccharide (Escherichia coli O55:B5) in the presence and absence of fetal bovine serum for 4 hours. Procoagulant activity was measured, using a chromogenic assay. RESULTS: None of the drugs was associated with a modification of procoagulant activity expression. CONCLUSION: Use of these 3 anti-inflammatory drugs is unlikely to modify the extent of the fibrinous reaction commonly observed in cases of acute bovine respiratory tract disease complex. CLINICAL RELEVANCE: The alveolar macrophage has a key role in fibrin production. Assuming in vivo events mimic the in vitro model, is appears unlikely that administration of anti-inflammatory drugs will reduce the procoagulant activity of the bovine alveolar macrophages and the directly associated pulmonary fibrosis.

Allergic rhinitis in a herd of cattle.

Allergic rhinitis was identified in a herd of Hereford cattle. Affected cattle had clinical signs of rhinitis (eg, nasal discharge, sneezing, nasal irritation, and nasal pruritus) and multiple small proliferative lesions in the nasal passages. Eosinophils were the predominant cell type in nasal discharges, and histologic examination of nasal mucosa biopsy specimens revealed chronic proliferative eosinophilic rhinitis. Results of CBC were normal; plasma fibrinogen concentrations were within reference limits. Results of intradermal allergen sensitivity testing and an ELISA for allergen-specific IgE only suggested an exaggerated IgE-mediated response to environmental allergens. Allergen-specific IgG may have acted as a competitive blocking antibody and limited clinical signs of disease in some cattle.

Serum components enhance bacterial lipopolysaccharide-induced tissue factor expression and tumor necrosis factor-alpha secretion by bovine alveolar macrophages in vitro.

We have compared the effect of bacterial lipopolysaccharide (LPS) in combination with normal adult bovine serum (NBS), fetal bovine serum (FBS), or a bovine serum fraction on tissue factor expression and tumor necrosis factor alpha (TNF-alpha) secretion by bovine alveolar macrophages. At a concentration of 1 ng/ml, bacterial LPS alone failed to induce measurable tissue factor expression by the macrophages, but the presence of FBS, NBS, or a fraction of normal pooled bovine serum isolated by ion-exchange chromatography (fraction 2) markedly potentiated the effect of LPS. A protein concentration of 64 micrograms/ml NBS, 192 micrograms/ml FBS, and only 640 ng/ml fraction 2 was required to induce maximal tissue factor expression on the macrophages in combination with 1 ng/ml LPS. Comparison of quantities of added serum protein required to induce maximal potentiating effects indicated that fraction 2 was 100 times more potent than whole NBS and 300 times more potent than whole FBS. We similarly found that TNF-alpha secretion by macrophages exposed to LPS was responsive to serum and was highly responsive to fraction 2. LPS alone (1 ng/ml) induced a relatively low level of TNF-alpha secretion by the macrophages, and the presence of FBS, NBS, or fraction 2 potentiated the effect of LPS. A concentration of 64.0 micrograms/ml NBS, 320.0 micrograms/ml FBS, and 3.2 micrograms/ml fraction 2 serum protein induced near-maximal TNF-alpha secretion by the macrophages. Comparison of the concentration of serum protein required to induce these potentiating effects indicated that fraction 2 was approximately 20 times more potent than whole NBS and 100 times more potent than whole FBS. The stimulatory effect of LPS plus fraction 2 serum proteins was dependent on the CD14 receptor, as monoclonal antibodies directed against CD14 (My4, 60bd; 10 micrograms/ml) inhibited tissue factor expression and TNF-alpha secretion by the macrophages.

Radiographic and scintigraphic evidence of focal pulmonary neoplasia in three cats with hyperthyroidism: diagnostic and therapeutic considerations.

Three cats were diagnosed as hyperthyroid based on clinical signs, historical findings, laboratory abnormalities, and basal serum thyroxine (T4) concentrations, and/or nuclear thyroid scans. Additionally, a presumptive diagnosis of thyroid carcinoma with pulmonary metastasis was made in each cat based on radiographic or scintigraphic evaluation. All three cats had solitary pulmonary nodules 1.5 to 2 cm in diameter on survey thoracic radiographs; one cat also had chylous pleural effusion and pulmonary lobar consolidation. Focal pulmonary accumulation of sodium pertechnetate (99mTcO4-) and/or radioiodine (131I) corresponding to radiographic lesions were seen in all cats. Two cats were treated with single ablative doses (1111 to 1480 MBq) of 131I; the remaining cat was euthanatized. One of the treated cats died 8 days later; the other cat was euthanatized 22 weeks following treatment. Histopathologic examination of tissue obtained at necropsy confirmed metastatic thyroid carcinoma in one cat and bronchogenic adenocarcinoma in two cats. Our findings indicate that increased radionuclide uptake in focal pulmonary lesions and cytologic evaluation of tissue obtained by fine-needle aspiration are not specific for thyroid tissue.

Renal failure attributable to atrophic glomerulopathy in four related rottweilers.

Atrophic glomerulopathy resulting in chronic renal failure was diagnosed in 4 related Rottweilers, each < 1 year old. All 4 dogs had severe azotemia and massive protein-losing nephropathy. Histologically, the glomerular lesion was characterized by mild dilatation of Bowman's space, with glomerular tufts absent or markedly atrophied. The lesion is distinct from the congenital glomerular changes described in Samoyeds or Doberman Pinschers.

Stimulus-dependent actin polymerization in bovine neutrophils.

Polymorphonuclear leukocytes (PMNs) are responsible for much of the first wave of leukocyte-mediated host defense against microbial pathogens. In order to migrate through the endothelium of vessel walls, undergo chemotaxis, and phagocytize microbes, PMNs must modulate their cytoskeletal elements and undergo change of cellular shape. We have used fluorescence flow cytometric analysis and cellular microscopic observations to demonstrate actin polymerization in bovine PMNs and to examine the kinetics of PMN actin polymerization utilizing different PMN stimuli. In addition, we compared temporal relationships between cellular shape and actin polymerization. Actin polymerization occurred rapidly, and the kinetics of actin polymerization were similar for each of the three PMN agonists used, ZAS (10%), PAF (10(-6) M), and rhC5a (10(-7) M). Actin polymerization was near-maximal by 10 sec poststimulation (95.4% of maximal F-actin content attained by 10 sec poststimulation with ZAS stimulation), and reached peak values by 30 sec. The maximal increase in F-actin content of agonist-stimulated cells as compared to resting cells was 2.8-fold with ZAS; 2.3-fold with PAF; and 2.3-fold with rhC5a. PMN shape change (pseudopodia, membrane ruffles) was not as rapid, with only 22.4% of cells attaining visible membrane deformation by 10 sec and requiring 120 sec to reach peak shape-change values. After attaining peak values, the two events also differed. Whereas the percent of shape-changed PMNs remained plateaued up to 5 min poststimulation, the F-actin content gradually decreased after 30 sec, approaching F-actin values of unstimulated PMNs.

The power spectrum analyser as an indicator of cerebral ischaemia during carotid endarterectomy.

Stroke is a potential major complication of carotid endarterectomy and may be caused by cerebral ischaemia or embolisation from the operative site. Conventional EEG monitoring has been used intraoperatively to identify periods of cerebral ischaemia, but this monitoring technique can be difficult to operate and interpret in the operating room. This study reports the use of a new signal analyser, the power spectrum analyser (PSA-1, Neurologics, Inc., Nashville, Tennessee), and its impact on active patient management. Thirty-six patients undergoing carotid endarterectomies were monitored with the PSA-1 in conjunction with routine EEG. Eight patients (22%) showed evidence of ischaemia 22 times on both PSA-1 and routine EEG. At no time did the routine EEG show evidence of ischaemia when the PSA-1 did not. The PSA-1 has proven to be a reliable neurophysiologic monitor for the identification of periods of cerebral ischaemia. Use of this small, easily operated and interpreted machine could enhance safety in operating rooms lacking sufficient resources to use conventional EEG machines.

Failure of passive transfer in calves: comparison of field diagnosis methods.

Calves with serum immunoglobulin levels less than 800 mg/dl have a failure of passive transfer of maternal antibodies, those with 800-1600 mg/dl have a partial failure of passive transfer, and those with greater than 1600 mg/dl have adequate immunoglobulin levels. Tests for immunoglobulin level evaluation are most accurate when serum from healthy animals 1-8 days old is used. Of the sodium sulfite precipitation, zinc sulfate turbidity and glutaraldehyde coagulation tests, the first is the most useful field test for evaluation of serum immunoglobulin levels in calves. It is inexpensive, easy to perform and relatively accurate.

Subdural hematoma secondary to ruptured intracranial aneurysm: computed tomographic diagnosis.

This case report illustrates a cerebral aneurysm that bled into the subdural space without any clinical or radiographic evidence of subarachnoid hemorrhage. Both the aneurysm and the subdural hematoma were easily demonstrated on computed tomography scan. The incidence of this lesion and its possible etiology are discussed.

Knotted ventriculoatrial catheter. Case report.

In this patient a No. 5 French infant feeding tube was advanced through the right basilic vein into the superior vena cava, and became knotted around the end of an atrial catheter placed in the left common facial vein. The atrial catheter stretched sufficiently to allow excision of the knot as it came through the antecubital incision. It then snapped back up into the axillary vein. A shuntgram with 60% Renograffin demonstrated the position of the ventriculoatrial catheter in the axillary vein. Subsequently, the catheter slid back into the atrial position.

Cranial zygomycosis caused by Saksenaea vasiformis. Case report.

A previously healthy youth who had sustained severe head trauma and had received steroids and broad-spectrum antimicrobial agents developed a cranial zygomycotic infection with Saksenaea vasiformis. This is the first time this zygomycete has been implicated as a disease agent. Early identification of the fungal infection and subsequent vigorous medical and surgical therapy led to recovery.

Cerebrospinal fluid ascites: a complication of a ventriculoperitoneal shunt.

A 1 year old Caucasian male born with an omphalocoele, malrotation of the large bowel, and Ladd's bands developed an E. coli wound infection and subsequent meningitis-ventriculitis which responded to antibiotic therapy. Aqueductal stenosis and obstructive hydrocephalus initially was treated with a ventriculoperitoneal shunt. After a routine diphtheria-pertussis-tetanus immunization, the child developed a CSF ascites which resolved following a ventriculoatrial shunt.