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Biomedical subjects

T A Olson

Publications and source records attributed to T A Olson.

70 records · Page 4Linked to original sources
PubMed1987

Antimicrobial therapy of Broviac catheter infections in pediatric hematology oncology patients.

Long-term therapy of pediatric oncology patients has been facilitated by permanent indwelling venous catheters. Over a 3-year period, 54 Broviac catheters were placed in 43 oncology patients and two hemophiliacs. There were 20 episodes of sepsis in 14 patients and the most common bacteria were S epidermidis (4), S aureus (4), and K pneumoniae (3). Catheter exit site infections occurred ten times in six patients; S aureus eight of ten. Antibiotic therapy without catheter removal was successful in 18 of 20 children with catheter sepsis and 8 of 10 patients with exit site infections. These data strongly suggest that although catheter-related infections are common, removal of Broviac catheters is not required for successful treatment of the infection.

Anti-Bacterial Agents↗
PubMed1987

A group B streptococcal extract reduces neutrophil counts and induces neutrophil aggregation.

The possibility that group B streptococci (GBS) may induce neonatal neutropenia by promoting neutrophil aggregation and the entrapment of aggregates in the lung was studied in vivo and in vitro utilizing a cell free GBS extract [(GBS)-trichloroacetic acid (TCA)]. The intravenous infusion of the extract into neonatal lambs induced reductions of circulating white blood cells (0 time, 3.1 X 10(3)/mm3 +/- 0.5 versus 2.2 X 10(3)/mm3 +/- 0.7) 5 min after infusion (p less than 0.01). At necropsy these lambs had prominent accumulation of polymorphonuclear leukocytes in their pulmonary interstitium. Subsequently, neutrophil aggregation was studied by incubating GBS-TCA in human serum or phosphate-buffered saline with subsequent addition to human polymorphonuclear leukocytes in an aggregometer. GBS-TCA incubated in human serum induced prompt polymorphonuclear leukocyte aggregation (mean delta T 12.3% +/- 2.8 in human serum versus delta T 2.5% +/- 2.1 in phosphate-buffered saline, p less than 0.001). Preincubation of GBS-TCA followed by incubation in human serum with human GBS hyperimmune IgG significantly reduced aggregation (GBS-TCA in serum mean delta T 14.9 +/- 2.44 versus 5.42 +/- 1.80, p = 0.002). Cell-free GBS products may induce polymorphonuclear leukocyte aggregation in the presence of whole serum. This phenomenon might contribute to the pulmonary injury experienced by infants with GBS pneumonia and sepsis.

Animals↗
PubMed1985

Additive and heterosis effects on preweaning traits, maternal ability and reproduction from crossing of the Angus and brown Swiss breeds in Florida.

Angus (A), Brown Swiss (S) and A X S reciprocal F1 (AS) dams were mated to A, S and AS (also reciprocal F1) sires resulting in nine breed groups of progeny with varying proportions of Angus and Brown Swiss breeding. Breed group of dam and of sire significantly influenced birth weight, preweaning daily gain, weaning weight, 205-d weight, condition score and frame size. The means for birth weight and weaning weight were 33 and 213 kg, respectively. Brown Swiss bulls sired calves with the heaviest birth and weaning weights. Calves produced by S dams likewise were heavier at birth and weaning. Pregnancy rates were influenced significantly by year, age and breed of dam and averaged 79, 95 and 92% for S, AS and A cows, respectively. Survival rate averaged 97% and was not influenced significantly by any of the effects examined. Because survival rates were similar for all breed groups, the results for weaning rate paralleled those for pregnancy rate. Genetic influences on preweaning growth traits and survival rate were partitioned into additive breed differences (B) and heterosis (H) effects for direct (d) and maternal (m) components. Pregnancy and weaning rates were examined using similar analyses except that genotype of service sire of dam replaced that of the offspring for the direct additive breed and direct heterosis components. The Bd values indicated that the Angus breed was inferior (P less than .01) to the Brown Swiss breed for all preweaning growth traits except for condition score, in which the Angus breed surpassed (P less than .01) the Brown Swiss. The Bm values also showed an advantage for the Brown Swiss breed for all preweaning growth traits. The additive maternal effect (the genotype of the females exposed), Bm, was important for pregnancy rate and weaning rate (P less than .001 and P less than .05) but not for survival rate (P greater than .10). The direct additive breed effect was not important for any reproductive trait. Direct heterosis did not affect any of the preweaning or reproduction traits; however, maternal heterosis (Hm) significantly affected all traits except birth weight, frame score and survival rate. The Hm estimates were 12.0 and 8.4 kg for weaning weight and 205-d weight, respectively. The Hm estimates for pregnancy rate, survival rate and weaning rate were 10, 2 and 13%, respectively.

Animals↗
PubMed1983

Hepatic failure secondary to indicine N-oxide toxicity. A Pediatric Oncology Group Study.

Indicine N-oxide, a pyrrolizidine alkaloid, was given to a five-year-old boy with refractory acute myelocytic leukemia. Three days after receiving the drug the patient developed signs and symptoms of acute hepatic failure. The patient died nine days after receiving the drug and an autopsy showed massive hepatic necrosis. The acute hepatic failure observed in this patient may have been secondary to indicine N-oxide toxicity.

Antineoplastic Agents, Phytogenic↗
PubMed1983

Newborn polymorphonuclear leukocyte aggregation: a study of physical properties and ultrastructure using chemotactic peptides.

N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) and N-formyl-L-methionyl-L-phenylalanine (FMP) were used to investigate neutrophil (PMN) aggregation. Neutrophils were isolated from healthy adult volunteers and term newborn cord blood. Neutrophil aggregation was measured after the addition of FMLP and FMP. Adult PMN aggregation curves demonstrated initial aggregation with slow deaggregation. Newborn neutrophil aggregation curves showed slow aggregation with no deaggregation. These results were identical to the adult and newborn neutrophil aggregation curves produced by C5a. Newborn PMN aggregates examined by scanning electromicrography showed frequent, dense aggregates compared with fewer, less dense aggregates of adult PMNs. Adult and newborn PMN aggregates differed when compared by transmission electromicrographs (EM). Newborn PMNs were tightly bound with cell membrane projections; adult PMNs were loosely bound with no cell membrane projections. Cytochalasin-B pretreated adult and newborn PMN aggregates displayed close approximation of cell membranes with large numbers of cytoplasmic projections. Newborn neutrophils are irreversibly aggregated by FMLP and FMP whereas adult neutrophils display an aggregation-deaggregation reaction. EM studies suggest that this irreversible aggregation of untreated newborn neutrophils may differ from the irreversible aggregation of cytochalasin-B pretreated neutrophils.

Adult↗
PubMed1982

Cardiomyopathy in a child with hypereosinophilic syndrome.

A 9-year-old boy presented with increasing fatigue, anorexia, weight loss, fever, and absolute eosinophilia (48,000/microL). Pulmonary infiltrates occurred 3 months later. A murmur of mitral regurgitation was heard 5 months after onset of illness, and heart failure soon followed. Despite corticosteroid therapy the eosinophilia persisted intermittently until 1 month before death. The patient died within 9 months of the onset of illness. At necropsy there was cardiomegaly with subendocardial fibrosis in the right and left ventricles. Thrombi were present in the left ventricular apex and behind the posterior mitral leaflet. The findings in 12 previously reported pediatric cases are reviewed. The etiopathogenesis of the hypereosinophilic syndrome is discussed: half of the cases in children are associated with leukemia.

Cardiomyopathies↗
PubMed1981

Additive genetic and heterosis effects in crosses among cattle breeds of British, European and Zebu origin.

Breed and heterosis effects for maternal and calf components for weaning traits were measured in the progeny of Angus (A), Brahman (B) and Charolais (C) sires mated to A, B, C and reciprocal AB, AC and BC dams. Additive breed effects for the calf component for weaning weight were -3.0 +/- 3.2, -26.6 +/- 3.1 and 29.6 +/- 3.3 kg for A, B and C, respectively. Corresponding maternal breed effects were -1.7 +/- 2.4, 7.8 +/- 2.3 and -6.1 +/- 2.6 kilograms. Heterosis effects on weaning weight for the calf component were 21.2 +/- 3.6 for AB, 1.4 +/- 3.7 for AC and 16.5 +/- 3.4 for BC crosses, while heterosis levels for the maternal component were 28.9 +/- 2.7 for AB, 16.5 +/- 3.2 for AC and 18.7 +/- 2.9 kg for BC dams. The corresponding estimates for condition scores tended to parallel those for weaning weight. Approximate relative production efficiency rates were computed for the different mating groups as (calf weight divided by cow weight) x weaning rate. These values were .34 for purebred matings, .36 for purebred dams raising F1 calves, .40 for F1 cows raising backcross calves and .43 for F1 dams raising three breed crossbred calves.

Animals↗
PubMedDate not supplied

The genetic basis for piebald patterns in cattle.

Evidence is given for the existence of a dominant mutant, Bl, found in Simmental and some other breeds of cattle that is responsible for white facial pattern. This mutant is independent of the mutant responsible for the typical white facial and body pattern of the Hereford breed. Also, evidence is presented to support a multiple allelic series composed of SH (Hereford pattern), SCS (color-side pattern), S+ (non-spotted wild type), and s (recessive spotting pattern). Alleles SH and SCS are codominant to each other and incompletely dominant over S+, SH, SCS, and S+; all appear to be completely dominant over s. The Dutch belted pattern is probably controlled by an independent dominant mutant, Bt.

Animals↗