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Biomedical subjects

L D Miller

Publications and source records attributed to L D Miller.

At least 55 records · Page 3Linked to original sources
PubMed1988

Pathogenesis of Mycobacterium bovis infection in American bison.

Eighteen 12-month-old bison were randomly placed in each of 3 groups (6 animals/group): group-1 bison were exposed to live Mycobacterium bovis, group-2 bison were inoculated with killed M bovis in oil, and group-3 bison were noninfected controls. Six, 6-month-old, tuberculin test-negative calves were placed (pen contact) with group-1 bison 30 days after exposure to M bovis. Tuberculin skin test responses (caudal fold and/or comparative cervical) were detected in all bison in groups 1 and 2 at 2, 4, 6, 10, and 12 months. Tuberculin skin test responses were observed in 2 of 6 calves at 9 and 11 months after pen contact with M bovis-exposed bison (group 1). Statistically significant lymphocyte blastogenic responses to M bovis purified protein derivative were detected in group-1 bison exposed to live M bovis at 2 months after exposure (P less than 0.025). Significant ELISA reactions were detected in sera of bison at 2 months after exposure to killed M bovis in oil (P less than 0.005) and in bison 2 months after exposure to live M bovis (P less than 0.01). Significant tuberculin skin responses, ELISA reactions, or lymphocyte blastogenic responses to M bovis purified protein derivative were not observed in the 6 control bison. Grossly visible tuberculous lesions were observed in lymph nodes and/or lung collected at necropsy in 4 of 6 bison at 12 months after exposure to live M bovis. Microscopic granulomas compatible with tuberculosis were detected in 5 of 6 bison; M bovis was isolated from tissues of each of the 6 bison.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Studies on the pathogenesis of heart lesions in dogs infected with pseudorabies virus.

Pseudorabies virus was inoculated by various routes into dogs to determine the relationship of pseudorabies virus to the development of heart lesions. Electrocardiograms and serum samples for lactate dehydrogenase isoenzymes were taken twice daily. Transitory and persistent arrhythmias were a consistent finding. Heart lesions were noted within each of the inoculated groups. These changes varied from severe multifocal areas of hemorrhage and myocardial degeneration to small zones of myolysis. A ganglioneuritis of the stellate ganglia and autonomic ganglia within the heart were also consistent findings. Herpes-like viral particles were found by electron microscopy in various autonomic ganglia and in myocardial endothelial cells. No viral particles were found in myocardial cells. Significant increases in lactate dehydrogenase-1 were noted. It was concluded that fatal arrhythmias resulted from pseudorabies virus infections in the dog after the occurrence of myocardial and ganglionic lesions.

Animals↗
PubMed1985

Blood from bovine leukemia virus-infected cattle: antigen production correlated with infectivity.

Leukocytes from 1 ml of blood from cattle seropositive to the bovine leukemia virus were cultured for 3 days and then tested by radioimmunoassay for antigen production. Infectivity of blood from each animal was also tested by calf inoculation and subsequent serologic detection of bovine leukemia virus transmission by agar-gel immunodiffusion. In a preliminary experiment, blood from each of 3 antigen-positive cattle was inoculated intracutaneously into 2 calves in volumes of 20 or 100 microliter. Blood from each of 4 antigen-negative cattle was similarly inoculated into 3 calves in volumes of 20, 100, or 500 microliter. At the termination of the experiment (8 weeks after inoculation), all 6 calves given blood from antigen-positive cattle had seroconverted, and 11 of 12 calves given blood from antigen-negative cattle had seroconverted. In a 2nd experiment, blood from each of 2 antigen-positive and 2 antigen-negative cattle was inoculated into pairs of calves in volumes of 1, 10, or 20 microliter. At the end of the experiment (12 weeks after inoculation), all calves inoculated with blood from antigen-positive cattle had seroconverted, but only 6 of 12 calves that had been given blood from antigen-negative cattle had seroconverted. The relative infectivity of blood was best illustrated by comparing results from the 1-microliter inoculations. At that volume, the 4 calves given blood from antigen-positive cattle were infected, whereas none of 4 calves given blood from antigen-negative cattle was infected.

Animals↗
PubMed1983

Efficacy of glucocorticoids in preventing mitochondrial metabolic failure in endotoxemia.

Endotoxemia was induced in rats and guinea pigs by an intraperitoneal injection of E coli endotoxin. In the rat, the dose used (3 mg/100 g body weight) resulted in a 60% mortality in 24 h. The same dose in the guinea pig resulted in a similar mortality at 24 h, and a 100% mortality by 3 days. Methylprednisolone Na-succinate, a glucocorticoid, given simultaneously with the endotoxin, prevented mortality in the rats. No animals died during the observation period. In the guinea pigs the same treatment protected all animals for 24 h, and resulted in an 80% survival rate over a 6-day observation period. Administration of glucocorticoids 1 or 2 h after endotoxin showed diminished efficacy. About 60% of the guinea pigs died during the 6-day observation period. Rat kidney and guinea pig brain and kidney mitochondria were isolated and analyzed for their function in untreated and treated animals 24 h after the injection of endotoxin. Rat kidney mitochondrial O2 utilization and ATP synthesis function, as well as Ca++ transport activity, were significantly below normal in the untreated animals, but did not differ from normal in glucocorticoid-treated animals. In untreated and at zero time treated guinea pigs similar results were found in brain and kidney mitochondrial functions. If treatment was delayed for 1 or 2 h, however, brain mitochondrial O2 utilization and ATP synthesis rates were significantly below normal, and both brain and kidney mitochondrial Ca++ transport capacities remained significantly lowered. The data support the efficacy of early glucocorticoid treatment in endotoxemia. Early glucocorticoid treatment prevents the deterioration of brain and kidney mitochondrial function.

Animals↗
PubMed1980

Bovine viral diarrhea infection in pregnant swine.

Twenty pregnant gilts (5 groups of 4) were infected experimentally with 1 of 4 strains of bovine viral diarrhea virus (BVDV) administered intranasally-orally. Blood specimens were taken from the gilts on postinfection day (PID) 7 and cultured for virus. Serum specimens, obtained on PID 21 and at termination of the experiment, were tested for neutralizing antibodies. At 90 to 112 days of gestation, the gilts were euthanatized and their fetuses were examined for evidence of intrauterine infection. Evidence of infection was demonstrated in all of the gilts, either by isolation of BVDV at PID 7 or subsequently by detection of neutralizing antibody titers. Intrauterine infection was confirmed in one of 20 gilts by isolation of BVDV, detection of neutralizing antibodies, and demonstration of microscopic lesions in the fetuses. The microscopic lesions were characterized as nonsuppurative meningitis and choroiditis. Clinical signs of disease were not seen in the infected fetuses. Of 8 gilts exposed to strains of BVDV pathogenic for cattle, 1 gilt developed intrauterine infection, 2 gilts were found barren, and 3 gilts had significantly fewer fetuses than copora lutea.

Animals↗
PubMed1980

Isolation of pseudorabies virus from trigeminal ganglia of a latently infected sow.

A 2-year-old sow with a relatively low virus-neutralization (VN) titer (1:8) against pseudorabies virus (PRV) was brought to the National Animal Disease Center for observation and study. The sow was kept in isolation for approximately 6 weeks, and repeated nasal and tonsillar swabs for virus isolation and blood samples for VN tests were obtained during this interval. At the end of 5 weeks' observation, the sow was injected IM with 200 mg of dexamethasone and was euthanatized 1 week later. Parts of the two trigeminal ganglia, tonsillar tissue, and nasal secretions were cultured in porcine kidney cells. The rest of the trigeminal ganglia was extracted with phenol and tested for presence of the PRV-DNA genome by hybridization with tritiated complementary RNA. The PRV was isolated from the trigeminal ganglia only, and the PRV genome was demonstrated in the same tissue. This latently infected sow was a potential shedder of PRV.

Animals↗
PubMed1979

Oxybutynin influence on autonomic measures in dogs.

In the conscious dog, the most apparent oxybutynin effect was a dose-related tachycardia. Associated with this heart rate increase were a very slight, sometimes significant, elevation in diastolic pressure and an insignificant increase in systolic pressure. Under pentobarbital anesthesia, the systolic/diastolic arterial pressure oxybutynin responses were reversed and showed a dose-related systolic and diastolic hypotension. However, the tachycardic response to oxybutynin still appeared. The arterial pressure and heart rate responses produced by the autonomic agents were altered by the oxybutynin treatment in a pattern indicative of an anticholinergic mechanism of action. Differences in many response profiles were observed with either conscious or anesthetized dogs, but the statistically significant inhibition of the acetylcholine-induced systolic and diastolic arterial pressure and bradycardic responses were constant in both conditions. Oxybutynin is an anticholinergic agent with mild to moderate cardiovascular activity.

Anesthesia↗
PubMed1978

Skeletal manifestations of polymyalgia rheumatica.

In a review of 39 patients with polymyalgia rheumatica (PMR), sternoclavicular and acromioclavicular arthropathy was noted in 15% and 10% of the patients, respectively. Diffuse clavicular swelling preceded the onset of PMR in one patient. Carpal tunnel syndrome was seen in four patients (10%).

Acromioclavicular Joint↗
PubMed1978

Improved renal function and inhibition of renin and aldosterone secretion following peritoneovenous (LeVeen) shunt.

Twelve patients with cirrhosis, refractory ascites, and varying degrees of renal failure (creatinine clearance, 5 to 44 ml/min) were studied before and up to 2 weeks following peritoneovenous shunt. Creatinine clearance increased 60% or more in seven patients (group I) and 22% or less in five patients (group II). There were no significant differences in maximum urine output or sodium excretion between groups (group I, 4,272 ml/14 hr, 372 mEq/24 hr; group II, 3,722 ml/24 hr, 255 mEq/24 hr). Aldosterone and renin concentrations were higher in group I and showed a greater decrease after shunting. Renin substrate levels also were higher in group I and rose following shunt insertion, while group II remained low. Ascitic fluid was found to contain renin substrate in concentrations of approximately 25% to 50% of plasma concentrations. Patients with the greatest increase in creatinine clearance showed the largest rise in substrate concentration and fall in renin and aldosterone secretion, suggesting a dynamic relationship between these factors. That a diuresis could occur without significant change in these parameters in five of 12 patients suggests independent control mechanisms for renal salt and water excretion and glomerular filtration in the ascitic patient.

Aldosterone↗
PubMed1976

Orthostatic influences on cardiovascular responses to nitroglycerin in conscious dogs.

The influence of body position change on the arterial pressure and heart rate responses produced by acute short-acting and sustained-release dosage forms of nitroglycerin was evaluated in a series of chronically prepared, conscious beagle dogs. The upright repositioning of the dog to 60 degrees from horizontal markedly enhanced the hypotensive and bradycardic responses produced by both dosage forms. Since it has been suggested that the lowering of arterial pressure is an essential component resulting in the therapeutic usefulness of nitroglycerin in angina pectoris, the experimental orthostatic model could be a sensitive procedure for the laboratory assessment of drugs of this class.

Animals↗