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Biomedical subjects

L J Olson

Publications and source records attributed to L J Olson.

At least 55 records · Page 3Linked to original sources
PubMed1985

Surgical pathology of combined aortic stenosis and insufficiency: a study of 213 cases.

The gross surgical pathologic features of the aortic valve were reviewed in 213 patients who had had clinically combined aortic stenosis and insufficiency and aortic valve replacement at our institution during the years 1965, 1970, 1975, and 1980. The three most common causes were postinflammatory disease (69%) and calcification of congenitally bicuspid (19%) and unicommissural (6%) aortic valves. Other causes included infective endocarditis (2%) and congenitally quadricuspid or malformed tricuspid aortic valves (1% each); the cause was indeterminate in 1%. In the postinflammatory and bicuspid states, calcification tended to be more extensive in men than in women. The relative incidence of postinflammatory disease in our study did not change appreciably from 1965 to 1980, despite the steadily decreasing incidence of acute rheumatic fever reported in western countries.

Adult↗
PubMed1984

Immunosuppression in weanling and adult Sprague-Dawley rats induced by acute exposure to 3,3',4,4'-tetrachloroazoxybenzene.

The acute immunomodulatory effects of the environmental and occupational contaminant, 3,3',4,4'-tetrachloroazoxybenzene (TCAOB), were investigated on selected immune parameters in weanling and adult Sprague-Dawley rats. Significant immunotoxic effects were found 17 days after 4 doses of 25 mg/kg TCAOB, administered i.p. The main non-immune toxic effects were decreased body, kidney, heart and testis weights, and a simultaneous increase in liver weight. The immune parameters showing significant suppression were: thymic weight, splenic plaque forming cell populations and function, pertioneal macrophage chemiluminescence, and bone marrow cellularity. Weanling animals were affected by TCAOB to a greater extent than adults on both the multiple and single dose regimens. The immunotoxic effects were found to be qualitatively similar to those of its isosteric analog, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The results demonstrate that TCAOB is a very potent immunotoxic compound and may have long-term effects after a single exposure. This study is the first investigation into the effect of TCAOB on immune functions.

Aging↗
PubMed1984

Toxicant-disease-environment interactions associated with suppression of immune system, growth, and reproduction.

The effects of marginal malnourishment , infections, and environmental chemicals on growth and reproductive success in Swiss-Webster white mice and wild deer mice were studied with fractional factorial designs. Interaction effects were discovered. For example, malnourished mice were more sensitive to virus exposure and environmental chemicals (a plant growth regulator or polychlorinated biphenyls). Since several commercial plant growth regulators also appear to suppress the immune system, these results cast doubt on the adequacy of current toxicity testing procedures in which factors are studied individually and not in combination.

Animals↗
PubMed1984

Effects of ingestion of chlorocholine chloride and cyclophosphamide on Venezuelan equine encephalitis virus infections in deer mice (Peromyscus maniculatus).

We investigated the effects of chlorocholine chloride (CCC), a plant growth regulator, and cyclophosphamide (CP), a known immunosuppressant, on the ability of deer mice (Peromyscus maniculatus) to resist challenge with a sublethal dose of Venezuelan equine encephalitis virus ( VEEV ). The toxicants were continuously delivered in low doses in the feed; CP at 20 mg/kg body wt/day and CCC at 1, 10, 20 or 40 mg/kg body wt/day. Mice were inoculated with 3 X 10(4) plaque forming units (pfu) of VEEV after eating experimental feed for 23 days. Mice were bled daily for 7 days and at selected intervals from 8 to 63 days post inoculation (PI) for viremia and antibody titer determinations. CP treatment increased the duration of viremia and significantly (P less than or equal to 0.05) decreased mean viremia titers. Antibody titers were significantly (P less than or equal to 0.05) depressed in CP-treated mice compared to controls. CP treatment increased mortality. CCC had no effect on viremia duration or titer except when given in doses of 1 mg/kg body wt/day when it significantly (P less than or equal to 0.05) decreased mean viremia titers compared to controls. Early antibody responses were increased by CCC treatment except in the 10 mg/kg body wt/day treatment group in which titers were decreased. By 30 days PI antibody titers of CCC-treated mice were no different from controls.

Animals↗
PubMed1984

Influence of feeding chlorocholine chloride and glyphosine on selected immune parameters in deer mice, Peromyscus maniculatus.

Exposure to the plant growth regulators, chlorocholine chloride (CCC) and glyphosine (GPS), resulted in significant immunomodulatory effects after feeding to deer mice (Peromyscus maniculatus) for 28 days. Cyclophosphamide (CP) and saline controls were included. Both CCC and GPS feeding levels were equivalent to 1, 10, 20, 40 and 80 mg/kg mouse/day. The parameters assessed were: spleen plaque forming cell (PFC) assays, hemolysin titers, white blood cell counts, bone marrow cellularity, hematocrits, plasma proteins, and spleen, liver, kidney, thymus and body weights. GPS significantly raised the ratio of liver/body wt, lymphocytes/g of spleen (at high doses only) and hemolysin titers (at low doses only). Lymphocyte viability was significantly reduced, while WBC counts and plasma protein levels were moderately lowered. CCC significantly reduced plasma proteins, PFCs/g of spleen, lymphocyte viability and hemolysin titers. It also affected thymus weights, WBC counts, lymphocytes/g of spleen and PFCs/10(6) lymphocytes. Most of the effects for both compounds followed a typical dose-response curve, but GPS gave a bimodal response in certain tests. The results demonstrate that CCC and GPS can act as immunomodulatory agents and show the feasibility of using deer mice for immunotoxicity studies of environmental contaminants and agricultural chemicals.

Animals↗
PubMed1984

Surgical pathology of pure aortic stenosis: a study of 374 cases.

The gross surgical pathologic features of the aortic valve were reviewed in 374 patients who had had clinically pure aortic stenosis and aortic valve replacement at our institution during the years 1965, 1970, 1975, and 1980. The most common cause of aortic stenosis, accounting for 46% of our cases, was calcification of a congenitally bicuspid valve. In the remainder, stenosis was produced by postinflammatory fibrocalcific disease (including rheumatic disease) in 35%, by degenerative calcification of an aging valve in 10%, and by calcification of a congenitally unicommissural valve in 6%. The cause of aortic stenosis was indeterminate in 4%. Valvular lesions included various degrees of dystrophic calcification, commissural fusion, and cuspid fibrosis. Calcification tended to occur more extensively and at a younger age in men than in women. Furthermore, it tended to produce stenosis and to necessitate valve replacement earliest in patients with unicommissural valves (mean age, 48 years), later in those with bicuspid or postinflammatory valves (mean age, 59 and 60 years, respectively), and latest in those with degenerative stenosis (mean age, 72 years). In our study, the relative incidence of postinflammatory aortic stenosis remained unchanged from 1965 to 1980, despite the steadily decreasing incidence of acute rheumatic fever reported in western countries. Our data suggest that (1) the incidence of chronic rheumatic heart disease has not yet begun to decrease appreciably, (2) many episodes of acute rheumatic fever may be subclinical, or (3) some forms of nonrheumatic aortic valve disease may produce gross alterations indistinguishable from those of classic chronic rheumatic valvulitis.

Adult↗
PubMed1984

Hemorrhagic cardiac tamponade: a clinicopathologic correlation.

Staphylococcus aureus pericarditis and recurrent episodes of hemorrhagic cardiac tamponade developed in a 31-year-old man. He later died of exsanguination and at autopsy was found to have a ruptured infective pseudoaneurysm of the aortic arch. When hemorrhagic pericardial effusions of undetermined cause are encountered, the heart and great vessels should be evaluated as potential sources of the hemorrhage.

Adult↗
PubMed1984

Surgical pathology of pure aortic insufficiency: a study of 225 cases.

The gross surgical pathologic features of the aortic valve were reviewed in 225 patients who had had clinically pure aortic insufficiency and aortic valve replacement at our institution during the years 1965, 1970, 1975, and 1980. The four most common causes of aortic regurgitation were postinflammatory disease (46%), aortic root dilatation (21%), incomplete closure of a congenitally bicuspid aortic valve (20%), and infective endocarditis (9%). Other causes of aortic incompetence in our study included ventricular septal defects (2%) and quadricuspid aortic valves (1%); the cause was indeterminate in 1%. The mean age of patients at valve replacement was approximately 50 years for all etiologic factors except a ventricular septal defect. All forms of aortic insufficiency were much more common in male than in female patients, except the postinflammatory and indeterminate types, which occurred approximately equally in both sexes. Moreover, the incidences of postinflammatory disease and aortic root dilatation changed appreciably with time. Before 1980, their incidences were 51% and 17%, respectively, but during 1980, they were 29% and 37%, respectively. Accordingly, aortic root dilatation is now the most common cause of pure aortic regurgitation in our surgical population. The decrease in the incidence of postinflammatory disease may be a result of the decreasing incidence of acute rheumatic fever reported in western countries.

Adult↗
PubMed1983

The immunomodulatory effects of two plant growth regulators, cycloheximide and maleic hydrazide, in white mice.

The immunomodulatory effects of two plant regulators, cycloheximide and maleic hydrazide, were investigated by injecting the compounds twice weekly for 4 weeks in female Swiss Webster white mice. The animals were antigenically challenged with sheep red blood cells on day 24 of the study. Although humoral immunity was the primary system examined, analysis included all of the following parameters: spleen plaque forming cells (PFC's), lymphocyte viability, spleen lymphocyte counts, hemolysin titers, total plasma proteins, total white blood cells counts, hematocrit, total body weight, and liver, thymus and spleen weights. Cyclophosphamide and physiological saline were used as the respective positive and negative control substances. The dosing was as follows: cyclophosphamide at 50 mg/kg/injection, cycloheximide at 12.5, 25 and 50 mg/kg/injection and maleic hydrazide at 125 and 250 mg/kg/injection. Cycloheximide significantly (P less than .05) reduced, in a dose-dependent fashion, the thymus wt/gram of body weight, the number of PFC's/gram of spleen, total lymphocytes/gram of spleen, PFC's per 10(6) viable spleen lymphocytes and the hemolysin antibody titer levels. Maleic hydrazide significantly reduced thymus weights and moderately lowered the ratio of PFC's per 10(6) viable spleen lymphocytes. Maleic hydrazide significantly elevated total lymphocytes per gram of spleen and the hemolysin titer (up to 133% over saline control values). There was an elevation in the number of PFC's per gm of spleen by maleic hydrazide and the overall effects were dose related. Cycloheximide, a known inhibitor of protein synthesis, was distinctly the most suppressive of the two plant growth regulators. Both agents are widely utilized on agricultural products and the results suggest the need for care in their application and residue removal. Used properly, the plant growth regulators may pose little or no human health hazard, but this report documents a new biological activity for these agents.

Animals↗