Possible electrocardiographic diagnosis of pericarditis in a horse.
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Animals↗
Biomedical subjects
D R Gross
Publications and source records attributed to D R Gross.
A search for ultrasonic cavitation within the canine cardiovascular system.
Resonant bubble detectors (RBD) were used to search for both pre-existing bubbles and bubbles created by cavitation within the cardiovascular system of 22 dogs. No pre-existing bubbles of 3.8 micron diam or larger were found, nor were any created by exposing the left ventricle to 0.51-1.61 MHz ultrasound of up to 16 W/cm2 spatial-peak intensity. Bubbles introduced into the arterial system by high speed injection were readily detected and could be held in the heart by 1 MHz ultrasound at 1-2 W/cm2 or above. A surprising observation was that gas bubbles of resonant size injected into the left ventricle and held by ultrasound did not multiply continuously as happens in saline or water in vitro. This in vivo system was designed to assess the potential for cavitation bioeffects and the essentially negative results obtained may limit the expected or potential risk of this mechanism in regard to medical applications of ultrasound.
Animals↗
Neuropathology of mitral valve prolapse in man and cardiopulmonary bypass (CPB) surgery in adolescent Yorkshire pigs.
We investigated the brains of non-demented individuals with mitral valve prolapse (MVP) and found evidence of Alzheimer-like lesions. This neuropathology consisted of premature presence of beta-amyloid-containing senile plaques (SP) without increased prevalence of neurofibrillary tangles. Low levels of SP occurred in 20 to 45- year-old subjects with MVP, and much greater densities were observed in subjects between 45 and 62 years of age. We also investigated the brains of adolescent Yorkshire pigs undergoing cardiopulmonary bypass surgery and likewise found evidence of Alzheimer-like neuropathology. This took the form of intraneuronal accumulation of beta-amyloid immunoreactivity and increasing numbers of Alz-50 immunoreactive neurons with reduced recovery of cardiac efficiency after the surgery. Based on prevailing concepts in Alzheimer's disease, it is feasible to hypothesize that cognitive dysfunction occurring after cardiopulmonary bypass surgery with coronary artery grafting or valve repair/replacement is a functional sequela of AD-like neuropathology. This postulate is based on the premise that an individual seeking such surgery would have pre-existing, elevated AD-like neuropathology to start with. It is further coupled with the probability that these forms of cardiovascular surgery exacerbate the extent and progression of AD-like neuropathology.
Adult↗
Quantitation of adsorption and conjugation of plasma proteins by residual glutaraldehyde in fixed collagenous tissue with radioiodinated plasma proteins.
Residual glutaraldehyde (GA) in collagenous cardiovascular tissue prostheses after multiple saline rinses remains in the prostheses and accounts for adsorption and conjugation of a variety of plasma proteins. This may account for later beneficial or adverse effects. Human serum albumin (SA), gamma globulin (GG), and fibrinogen (FB) were iodinated with 125I using the iodogen-transfer technique. Bovine pericardium (PC) was fixed with 0.5% GA for 24 hr and rinsed to remove excess GA. Fresh and GA-fixed PC (FRPC, GAPC: 1 x 1 cm2), in triplicate, were incubated with 0.5-1.0 microCi of tracers in human, porcine, or bovine blood (2 ml) for a period of 0.5, 1, 2, and 3 hr and washed (5x) with saline. Maximum adsorbed proteins per unit weight of collagen (pmol/mg of PC, mean +/- SD) at 3 hr on FRPC and GAPC were quantified with a gamma counter. Fixed PC absorbed significantly more plasma proteins from blood than fresh PC. These conjugated plasma proteins are tightly bound to fixed PC. The adsorbed and conjugated plasma proteins for GAPC and FRPC have the same sequence: SA > GG > FB vs SA > GG > FB. Protein conjugation may affect the remodeling of collagenous cardiovascular tissue prostheses post implantation.
Adsorption↗
Ammonia inhalation toxicity in cats: a study of acute and chronic respiratory dysfunction.
Twenty healthy conditioned cats were pulmonary-function tested and then exposed to 1000 ppm of ammonia gas for a 10-min period. Pulmonary function tests were repeated and lung samples for pathologic evaluation were taken on days 1, 7, 21, and 35 post-exposure. Two cats were housed with the experimental cats as untreated controls. Pulmonary function data were analyzed, statistically evaluated, and compared with the pathological observations. There was good correlation between the alterations in pulmonary function observed and the pathologic lesions found. According to our findings, and those of other investigators, the pulmonary dysfunction which results from ammonia gas inhalation is biphasic in nature. The acute effects of the initial insult, which can be fatal, are almost always followed by secondary effects which can result in debilitating, chronic respiratory dysfunction. This study has characterized an animal model which could provide techniques for preventing or modifying the course of the secondary damage of ammonia gas inhalation.
Airway Resistance↗
Successful prosthetic mitral valve implantation in pigs.
Clotting mechanisms, the coagulation cascade, platelet function, and platelet-leukocyte-endothelial cell interactions are all very similar in humans and pigs. Because of these similarities, the authors concluded that the pig would be an ideal model for the study of thromboembolism resulting from prosthetic heart valves. To date, they have successfully recovered a total of 11 pigs (52.9 +/- 8.1 kg), 3 with bioprosthetic valves and 8 with mechanical valves, all in the mitral position (25 mm od). The normal presence of high numbers of pulmonary endothelial macrophages and other unique aspects of porcine cardiovascular and pulmonary function dictate somewhat different surgical protocols than those normally used for human patients and ruminant species. Some of these special procedures include 1) crystalloid prime without the use of plasma volume expanders, especially those with a starch base; 2) pharmacologic protection against arrhythmias (lidocaine, 4 mg/kg); 3) special attention to adequate hypothermic cardioprotection during the time of cross-clamp; 4) the use of shock doses of corticosteroid (prednisolone sodium succinate, 0.5 mg/kg) before removal of the aortic cross-clamp; and 5) positive inotropic support (dopamine, 0.008 mg/kg) while weaning from cardiopulmonary bypass. Gamma camera images of 111In tagged autologous platelets 24 hours after surgery show most thrombi located on the sewing ring with fewer on the pledgets and anchor sutures. The latter observations were confirmed by quantification of platelet deposition using a gamma counter.
Animals↗