Idiopathic pulmonary arterial hypertension in a pot-bellied pig (Sus scrofa domesticus) with right-sided congestive heart failure.

Idiopathic pulmonary arterial hypertension is a rare disease reported in humans and dogs diagnosed as persistent elevation of pulmonary arterial blood pressure without predisposing or associated diseases. A four-month-old pot-bellied pig (Sus scrofa domesticus) was presented for decreased appetite, lethargy, respiratory distress, and occasional syncope. On physical examination, the pig was tachypneic with labored breathing, with a distended abdomen and a bilateral grade 4-5/6 parasternal systolic heart murmur. Systolic pulmonary arterial pressure was estimated at 95 mmHg by Doppler echocardiography, consistent with severe pulmonary hypertension. At autopsy, there was dilation of the main pulmonary artery and right ventricle. The lungs were diffusely rubbery, and there was tricavitary effusion. Microscopically, there was severe widespread pulmonary arterial concentric medial hypertrophy with rare plexiform lesions. The clinical history and gross and microscopic findings supported a diagnosis of idiopathic pulmonary arterial hypertension with subsequent right-sided congestive heart failure. Primary (idiopathic) pulmonary arterial hypertension should be considered as a differential diagnosis in young pigs with right-sided congestive heart failure.

Comparison of CD34, CD31, and factor VIII-related antigen immunohistochemical expression in feline vascular neoplasms and CD34 expression in feline nonvascular neoplasms.

The diagnosis of vascular neoplasms is often facilitated by the use of immunohistochemical markers such as factor VIII-related antigen, CD31, and CD34. However, the relative sensitivity and specificity of these markers have not been compared in cat vascular neoplasms. In this study, these 3 immunohistochemical markers were evaluated in 61 endothelial neoplasms (50 hemangiosarcomas and 11 hemangiomas) in 59 cats. All neoplasms were labeled by all 3 markers. CD34 had the highest average immunolabeling intensity in neoplastic endothelial cells. CD31 had the lowest average background labeling, followed by CD34 and factor VIII-related antigen, respectively. CD34 expression was also examined in 130 nonvascular neoplasms of cats; 14 of 62 epithelial neoplasms, 39 of 43 mesenchymal neoplasms, 8 of 23 leukocytic neoplasms, and 2 of 2 melanomas were positive. Given the broad expression of CD34 in mesenchymal neoplasms, this marker has limited diagnostic relevance for vascular neoplasms of cats.

Quantitation of basic fibroblast growth factor by immunoassay using BIAcore 2000.

A sensitive, accurate, and efficient immunoassay using a BIAcore 2000 biosensor instrument for the quantitation of basic fibroblast growth factor (bFGF) in HEPES-buffered saline containing 100 microg/ml heparin (HHBS) has been developed and validated. In this method, anti-bFGF monoclonal antibody 48.1 (MAb 48.1) was selected as a binding ligand and immobilized to the matrix surface of Sensor Chip CM5 by amine coupling. A high immobilization level of MAb 48.1 (12643+/-816 RU, mean +/- S.D., n = 5) was achieved with high reproducibility (i.e. coefficient of variation (CV) was 6.5%). This immobilized MAb 48.1 sensor surface was used to detect and quantity bFGF. This assay has a range of reliable BIAcore response from 5.65 to 1440 ng/ml bFGF in HHBS. which was well fitted with a sigmoidal model. The immobilized MAb 48.1 was found to be stable for at least 150 regeneration cycles and for at least 9 days at room temperature. Intra- and interassay CVs ranged from 0.9 to 5.9%, and from 2.7 to 8.5%, respectively. Matrices such as serum, bovine serum albumin (BSA), and two pharmaceutical excipients (Pluronic F127 surfactant and sodium carboxymethylcellulose) did not interfere with bFGF analysis over the sensor surface. Therefore, this validated assay has good precision, accuracy and specificity, and has been found useful in quantifying bFGF in several research and development studies.

Thermodynamic analysis of the heparin interaction with a basic cyclic peptide using isothermal titration calorimetry.

Brain natriuretic peptide (BNP) was examined as part of a continuing study of the interaction of proteins and peptides with the glycosaminoglycan heparin. BNP was tentatively identified as a heparin-binding protein on the basis of its cyclic structure and the high frequency of the basic amino acid residues, lysine and arginine. Thermodynamic analysis using isothermal titration calorimetry confirmed heparin binding to BNP with a micromolar Kd. Surprisingly, despite the high frequency (22%) of basic residues in BNP, only a small portion of the free energy of this interaction resulted from ionic contributions under physiologic conditions. The contribution of polar amino acids, representing 28% of BNP, was next examined in a variety of different buffers. These experiments demonstrated the transfer of five protons from buffer to BNP on heparin binding, suggesting that hydrogen bonding between the polar residues of BNP and heparin is a major factor contributing to the free energy of BNP binding to heparin. Hydrophobic forces apparently play only a small role in binding. Heparin contains few nonpolar functional groups, and a positive change in heat capacity (DeltaCp = 1 kcal/mol) demonstrates the loss of polar residues on BNP-heparin binding.