PubMed Health⌕ Search

Biomedical subjects

T A Olson

Publications and source records attributed to T A Olson.

At least 55 records · Page 3Linked to original sources
PubMed1994

Responses of bovine lymphocytes to heat shock as modified by breed and antioxidant status.

We tested whether resistance of lymphocytes to heat stress is modified by breed, intracellular glutathione content, and extracellular antioxidants. In the first experiment, lymphocytes from Angus (Bos taurus, non-heat-tolerant), Brahman (B. indicus, heat-tolerant), and Senepol (B. taurus, heat-tolerant) heifers (12 heifers per breed) were cultured at 45 degrees C for 3 h to evaluate thermal killing, at 42 degrees C for 12 h in a 60-h phytohemagglutinin-induced proliferation test, and at 42 degrees C for 1 h to measure induction of heat shock protein 70 (HSP70). Killing at 45 degrees C was affected by breed x temperature (P < .01); the decrease in viability caused by a temperature of 45 degrees C was greater for Angus than for Brahman or Senepol. For phytohemagglutinin-stimulated lymphocytes, heating to 42 degrees C reduced [3H]thymidine incorporation equally for all breeds. Viability at the end of culture was affected (P < .001) by a breed x temperature interaction because the decrease in viability caused by culture at 42 degrees C was greatest for lymphocytes from Angus heifers. Heat shock for 1 h at 42 degrees C caused a two- to threefold increase in intracellular concentrations of HSP70, but there was no interaction of temperature with breed. In another experiment (with lymphocytes harvested from three Holstein cows), buthionine sulfoximine, a glutathione synthesis inhibitor, inhibited (P < .01) proliferation of phytohemagglutinin-stimulated lymphocytes at 38.5 and 42 degrees C. Addition of the antioxidants glutathione or thioredoxin to culture did not reduce the effects of heating to 42 degrees C on proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Antibody response in patients with Gaucher disease after repeated infusion with macrophage-targeted glucocerebrosidase.

Recent clinical data have shown that enzyme replacement therapy with macrophage-targeted glucocerebrosidase (GCR) can be effective in treating type 1 Gaucher disease. Sera from 262 patients, repeatedly infused with GCR, were assessed for the presence of antibodies to this therapeutic protein. Patient serum samples obtained at 3-month intervals were assessed by enzyme-linked immunosorbent assay and those with values greater than two standard deviations above the mean value obtained with a pool of normal human sera were further characterized by radioimmunoprecipitation. At the time of these analyses, the duration of patient treatment varied from 3 months to approximately 3 years. Of the 262 patients analyzed, 34 (12.9%) showed IgG antibodies, as confirmed by radioimmunoprecipitation. All patients who seroconverted did so within 1 year of treatment. The predominant antibody developed was the IgG1 subclass. Fourteen patients in the study experienced periodic symptoms suggestive of immediate hypersensitivity. Nine of these 14 patients had antibody to GCR as determined by radioimmunoprecipitation, whereas 5 patients were antibody negative. There was no evidence of the development of IgE antibodies in these 14 patients. The presence of GCR antibodies did not appear to effect efficacy of therapy in any of the patients treated to date.

Antibodies↗
PubMed1993

Megakaryocyte colony stimulating activity in allogenic bone marrow recipients prepared with busulfan and cyclophosphamide.

Increased megakaryocyte colony stimulating activity (MK-CSA) has been reported after total body irradiation (TBI) for bone marrow transplant (BMT). We studied the effect of a busulfan (Bu) and cyclophosphamide (Cy) marrow transplant conditioning regimen, without radiation, on MK-CSA production. Initial screening of MK-CSA was done on previously collected and banked sera from 14 BMT patients. MK-CSA was expressed as the ability to stimulate growth of megakaryocyte progenitors (CFU-MK) in standard plasma clot cultures. In the initial samples, MK-CSA peaked at day 7. This preliminary data led to a prospective study of MK-CSA and clinical parameters in seven allogeneic recipients. MK-CSA activity increased from day -7 pre-transplant (2.9 +/- 1.7 CFU-MK/10(5) NATD, mean +/- SD) to day 0 (10.3 +/- 4.7 CFU-MK) and peaked by day 9 post-transplant (20.6 +/- 6.4 CFU-MK). MK-CSA activity decreased in all seven patients by day 21 at which time five of seven patients studied had recovery of platelet counts to greater than 100 x 10(9)/l. MK-CSA activity rose rapidly in both groups of sera after the initiation of this non-irradiation, BMT preparative regimen. High MK-CSA levels, early after transplant, may contribute to the rapid platelet recovery in some patients.

Adult↗
PubMed1993

Reproductive and maternal performance of rotational three-breed, and inter se crossbred cows in Florida.

Reproductive, calf growth, and cow weight data were collected during a 16-yr period in southern Florida. Data included 1,767 calves at weaning from purebred, F1, backcross, F2, and three-breed crossbred cows of the Angus (A), Brahman (B), and Charolais (C) breeds. The purebred cows primarily produced purebred calves, the F1 and F2 Cows produced inter se crossbred calves, and the backcross cows produced 3/8:5/8 calves. The 1/2 C:1/4 A:1/4 B three-breed crossbred cows were mated to A series, whereas three-breed crossbred dams with breed compositions of 1/2 B:1/4 A:1/4 C, and 1/2 A:1/4 B:1/4 C were mated to C and B sires, respectively. For analysis of additive breed and heterosis effects, pregnancy rate and cow weight were considered to be traits of the dam alone. The A additive breed effect increased (P < .05) pregnancy rate but reduced (P < .001) cow weight. The effects of AB, AC, and BC heterozygosity all increased pregnancy rate, but the advantage was greater for the crosses that involved B. Both AB and BC heterozygosity increased (P < .001) cow weight, whereas AC did not. The additive direct effect of B and C increased birth weight (BWT) and weaning weight (WWT). The additive maternal effect of B reduced BWT. The direct effect of AB heterozygosity increased BWT and WWT, and that of BC increased only WWT (P < .001). A comparable pattern was observed for maternal heterosis on weight traits. A much smaller effect of AC maternal heterosis on WWT was found. Pregnancy rates of F1, backcross, and three-breed dams were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effect of fenbendazole molasses supplement block treatment on nematode infection and subsequent weight gain of weanling beef calves.

Two trials were conducted to evaluate the effect of fenbendazole molasses supplement block treatment on weight gain of weanling beef calves. An initial (November) oral fenbendazole (5 mg kg-1) treatment was administered to all animals in both trials. In Trials 1 and 2, respectively, two fenbendazole molasses supplement block treatments were administered 6 (6.4 mg kg-1) and 16 (7.0 mg kg-1) weeks later and 7 (3.4 mg kg-1) and 14 (3.8 mg kg-1) weeks later. During the treatment periods, calves were maintained on dormant bermuda grass pasture, supplemented with hay and protein/mineral blocks. The first block treatment was administered approximately midway through the supplement period to suppress the infection level when nutrition was marginal. The second treatment was administered just prior to ryegrass grazing. Trial 1 and 2 treatments resulted in reducing the infection level, as indicated by reduced mean fecal egg counts. Treatment group mean fecal egg counts remained lower than control group mean counts throughout each trial. In Trial 1, the treatment group gained 29.5 kg more than the control group. In Trial 2, the control group gained 15.5 kg more than the treatment group. Fecal egg count data indicated that the infection level during Trial 1 was higher than during Trial 2. This difference could influence weight gain.

Administration, Oral↗
PubMed1992

Megakaryocytes and megakaryocyte progenitors in human cord blood.

Thrombocytopenia contributes significantly to morbidity in the sick term or preterm infant. However, few data exist on newborn's megakaryocytes and megakaryocyte progenitor cells (CFU-MK). We therefore studied CFU-MK in term and preterm infant cord blood and compared the results with data on CFU-MK from adult bone marrow and adult peripheral blood in a plasma clot culture with postirradiated aplastic canine serum (PIACS) as a source of megakaryocyte colony-stimulating activity. The number of CFU-MK and the number of cells per CFU-MK were counted with an immunofluorescent method at day 12. The effect of T-lymphocyte depletion on cord blood cultures for CFU-MK was studied with PIACS and a partially purified product of PIACS. We also studied individual megakaryocytes from newborns. The number and sizes of circulating megakaryocytes, isolated from adult peripheral blood and term venous cord blood by elutriation, were compared. Term and preterm cord blood contained more CFU-MK than adult peripheral blood. The numbers of CFU-MK in preterm cord blood were comparable to those in adult bone marrow. When the number of cells per colony were compared, cord blood contained significantly more cells than adult marrow CFU-MK. The depletion of T lymphocytes did not significantly change the growth of CFU-MK compared to nondepleted cultures. A substantial number of circulating megakaryocytes were obtained from venous cord blood, though they were significantly smaller than adult peripheral blood megakaryocytes. Since cord blood is easily obtained and contains large numbers of megakaryocytes and CFU-MK, it may provide a convenient model for studying the regulation of fetal megakaryocytopoiesis.

Animals↗
PubMed1992

Familial thrombocytopenia with micromegakaryocytes.

Chronic thrombocytopenia was noted in two siblings and a first cousin. The initial impression was of immune thrombocytopenic purpura (ITP) with decreased megakaryocytes. One patient had splenectomy for presumed chronic ITP but showed no improvement. Bone marrow buffy coat slides were examined in the three children with thrombocytopenia, four normal controls, and five children with "classic" acute ITP. Megakaryocyte size, maturation, and ploidy were determined with Wright-Giemsa and Feulgen-stained material. Mean megakaryocyte diameters were 23.1 microns in the three related patients, 30.8 microns in normal controls, and 63.1 microns in children with "classic" acute ITP. Many "micromegakaryocytes" were noted in the three related children with chronic thrombocytopenia. An exhaustive family history was obtained, which showed multiple points of consanguinity. These patients represent an apparently new autosomal recessive disorder of megakaryocytopoiesis, characterized by disturbed megakaryocyte ploidization and maturation. More sensitive recognition of micromegakaryocytes should be attempted in children with atypical chronic thrombocytopenia, familial history of thrombocytopenia, or patients who have ITP and who have not responded to initial therapy.

Bone Marrow Examination↗
PubMed1992

Growth patterns of two lines of Angus cattle selected using predicted growth parameters.

Linear functions of body weight and condition score at weaning and 18 mo of age were used to predict the mature weight (A) and maturing rate (k) parameters of an asymptotic growth model of Angus cows at the Subtropical Agricultural Research Station, Brooksville, FL. From 1981 through 1988 a heavy-mature-weight line (Line A) and a rapid-maturing line (Line K) were selected based on predicted A and k values. Linear contrasts (A-K) of least squares means for weight at fixed ages indicated that the weight difference between lines increased from birth to maturity during the period of the study. Animals from Line A were heavier (P less than .01) at all ages. A negative response in maternal ability, relative to increased growth potential of their calves, seems to have occurred in the cows of Line A. Mature weight was reached at approximately 4.5 yr of age in Line K and at approximately 5.5 yr in Line A. Brody's three-parameter and Richards' four-parameter functions were fitted to 2,855 quarterly weights of cows, from birth to 6.5 yr of age, to estimate the average growth curve for each line. Brody's model gave better estimates of weights from 18 mo to maturity, but the asymptotic residual mean squares were slightly higher because early weights were overestimated. Linear and nonlinear regression analyses of weight-age data and comparisons of degree of maturity at different premature ages showed differences in the growth patterns of the two lines selected for early predicted values of A and k.

Animals↗
PubMed1991

Effects of breed group by location interaction on crossbred cattle in Nebraska and Florida.

Data on 2,744 calves produced in Clay Center, Nebraska and Brooksville, Florida were used to evaluate the importance of genotype x location interactions on the reproductive and maternal performance of eight breed groups of F1 crossbred cows. A total of 648 F1 crossbred cows included Bos taurus x Bos taurus (Bt x Bt) crosses: Hereford x Angus reciprocal crossbreds (HA and AH), Pinzgauer x Angus (PA), Pinzgauer x Hereford (PH); and Bos indicus x Bos taurus (Bi x Bt) crosses: Brahman x Angus (BA), Brahman x Hereford (BH), Sahiwal x Angus (SA) and Sahiwal x Hereford (SH). The first calf crop was sired by Red Poll bulls. All remaining calf crops were sired by Simmental bulls. Although the pregnancy rate was 9% higher in Nebraska, the rate of unassisted calvings and calf survival rate were both 4.6% lower in Nebraska. Calf birth and weaning weights were 8.0 and 15.6 kg heavier in Nebraska than in Florida. Bi x Bt dams exceeded (P less than .001) Bt x Bt crossbred dams for all traits except age of calf at weaning and calf-survival rates (P greater than .10). Birth weights of calves from Bi x Bt crossbred dams were 3.4 kg lighter than those from the Bt x Bt crossbred dams. The interaction of location with the breed group comparison of Bi x Bt vs Bt x Bt crossbred dams was significant for pregnancy rate, calf age at weaning, rate of unassisted calving and all weight traits. Adjusted weaning weights of calves from HA, AH, PA, PH, BA, BH, SA and SH cows were as follows: HA, 194 and 222; AH, 202 and 230; PA, 213 and 242; PH, 217 and 245; BA, 251 and 254; BH, 252 and 254; SA, 236 and 238; and SH, 238 and 243 kg, respectively, in Florida and Nebraska. Bos indicus-sired cows (BA, BH, SA and SH) weaned essentially equal-weight calves at both locations, whereas calves from Bt x Bt crossbred cows (HA, AH, PA, PH) were about 28 kg lighter in Florida.

Animals↗
PubMed1991

Endocrine characteristics of a miniature condition in Brahman cattle: circulating concentrations of some growth-related hormones.

Four miniature Brahman calves born in 1988 and 1989, along with four contemporary sex-matched Brahman control calves, were used in experiments to determine circulating concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH), insulin, triiodothyronine, and thyroxine, and plasma glucose response to insulin challenge. The effect of plane of nutrition on plasma concentrations of IGF-I and insulin was also determined and a clinical screen of blood chemistries was conducted to determine effects of calf type. Plasma IGF-I was six times higher in control calves compared with miniature calves (209.0 vs 35.0 ng/ml; P = 0.001). However, miniature calves had mean plasma GH about six times higher (37.8 vs 6.2 ng/ml; P = 0.004) and had twice as many secretory episodes (9 vs 4.5; P = 0.005) over an 8-hr sampling period. Plasma concentrations of triiodothyronine (2.54 vs 1.80 ng/ml) and thyroxine (88.8 vs 56.2 ng/ml) were higher in control compared with miniature calves (P = 0.001), but concentrations of triiodothyronine and thyroxine in both calf types were within normal ranges. Although miniature calves displayed similar plasma glucose concentrations to controls, hypoglycemic response to insulin challenge tended to be greater in miniature calves. Nutritional regulation of circulating IGF-I appeared to be intact in miniature as well as control calves, as evidenced by a reduction in plasma IGF-I concentration following a decrease in plane of nutrition, and a subsequent increase in plasma IGF-I concentration following realimentation. Serum urea nitrogen was lower (P = 0.02) in control compared with miniature calves. These data describe a miniature condition in Brahman cattle that is manifested by apparently normal proportioned growth but small stature, and that is associated most notably with abnormally low circulating concentrations of IGF-I in the presence of paradoxically high circulating concentrations of GH. This condition appears to be similar to Laron dwarfism in humans, in which the low IGF-I is caused by an abnormality in the GH receptor.

Animals↗
PubMed1990

Direct and maternal genetic effects due to the introduction of Bos taurus alleles into Brahman cattle in Florida: I. Reproduction and calf survival.

Pregnancy rate, calf survival rate to weaning and calf age at weaning of several types of crossbred cows (2/3 or more Brahman) were compared to those of straightbred Brahman and Angus cows over a 12-yr period at Subtropical Agricultural Research Station near Brooksville, FL. The purpose of this study was to determine the relative importance of additive vs nonadditive genetic effects on reproductive and calf survival traits in a population of cattle whose foundation was selected on the basis of superior reproductive performance under harsh environmental conditions. Best linear unbiased estimates (BLUE) of direct additive effect (measured as the deviation of Brahman additive breed effect from Angus) for pregnancy rate and calf age, measured as traits of the dam, were 6 +/- 3% and -7.2 +/- 2.1 d, respectively. Thus, Bos taurus germ plasm did not increase pregnancy rate but resulted in an earlier calving date. The BLUE of nonadditive (intralocus) direct genetic effects measured as deviations from intralocus group genetic effects in the parental breeds on pregnancy rate and calf age at weaning were 25 +/- 4% and -6.4 +/- 2.5 d. Nonadditive effects on pregnancy rate were the primary cause of the superior reproductive rates observed in Brahman crossbred cows. Calf survival was considered to be a trait of the calf, and BLUE of direct additive, direct nonadditive, maternal additive and maternal nonadditive genetic effects was obtained. Only maternal nonadditive genetic effects were found to have a significant effect on survival rate (9 +/- 4%).

Alleles↗
PubMed1990

Direct and maternal genetic effects due to the introduction of Bos taurus alleles into Brahman cattle in Florida: II. Preweaning growth traits.

Records of birth weight (BW), weaning weight (WW) and condition score (CS) from 1,467 Brahman and Brahman X Angus crossbred calves from Brahman and crossbred Brahman sires and Brahman, crossbred Brahman and Angus dams were collected at the Subtropical Agricultural Research Station, Brooksville, Florida, from 1971 to 1982. Best linear unbiased estimates (BLUE) of Brahman sire and dam group additive genetic effects (as deviations from Angus) and Brahman X Angus dam and calf group nonadditive (intralocus) genetic effects (as deviations from intralocus group genetic effects in the parental breeds) were obtained. Linear combinations of these were used to compute direct and maternal Brahman additive and Brahman X Angus nonadditive (intralocus) group genetic effects. The respective BLUE of these four effects were 5.99 +/- 2.08, -5.70 +/- 1.91, .52 +/- 1.81 and 2.85 +/- .72 kg for BW; 9.60 +/- 10.29, 8.76 +/- 9.47, 9.47 +/- 8.96 and 20.95 +/- 3.56 kg for WW; and -1.10 +/- .55, 1.64 +/- .50, 1.47 +/- .47 and .05 +/- .19 units for CS. Linear combinations of the BLUE of sire, dam and calf group genetic effects can be used to predict the genetic worth of crossbred groups composed of any combination of Brahman and Angus breeding. Nonadditive maternal group genetic effects were the most important factor for BW and WW, whereas nonadditive direct group genetic effects were the most important for CS.

Alleles↗
PubMed1989

Effects of creep feeding, zeranol implants and breed type on beef production: I. Calf and cow performance.

A 2-yr study was conducted to evaluate the effects of a high-energy creep feed, preweaning zeranol implants and breed type on calf and cow performance. Two hundred calves sired by Brahman and Romana Red bulls out of Angus and Angus x Brown Swiss reciprocal crossbred (F1) dams were stratified by breed type and sex to three creep treatments: no creep feed (NC); long-term creep (LC), creep-fed from 56 to 210 d of age (weaning); and short-term creep (SC), creep-fed from 146 to 210 d of age. Alternate calves within sex, breed type and creep treatment were implanted with 36 mg of zeranol at an average of 56 d and reimplanted 90 d later. The LC and SC calves had heavier (P less than .001) 210-d weights than NC calves (264 and 257 vs 231 kg, respectively), and the LC calves were heavier (P less than .001) at 146 d than NC calves. The LC calves had higher (P less than .001) ADG from 118 to 210 d of age and higher 146 and 210-d condition scores than did NC calves. Pregnancy rate was not affected (P greater than .46) by creep treatment of calf. Zeranol implants increased (P less than .01) 146- and 210-d weights (184 vs 175 kg and 259 vs 243 kg) and ADG during all periods to weaning. Brahman-sired calves had higher (P less than .005) 146- and 210-d weaning weights and frame scores than Romana Red-sired calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1989

Effects of creep feeding, zeranol implants and breed type on beef production: II. Reproductive development and fat deposition in heifers.

Effects of preweaning creep feeding and zeranol implants on reproductive tract development and udder and s.c. fat deposition were studied in 24 weanling heifers (7 mo of age) with Brahman and Romana Red sires and Angus and Angus x Brown Swiss F1 reciprocal crossbred dams. Creep treatment did not affect (P greater than .19) ovarian weight, ovarian size, uterine horn diameter or follicle number. Heifers from the three creep treatments did not differ (P greater than .25) in udder weight, total lipid or percentage of lipid in the udder. Noncreep-fed (NC) heifers had a greater (P less than .02) number of adipocytes/gram of udder tissue than did the long-term creep-fed (LC) and short-term creep-fed (SC) heifers. The LC heifers had larger udder (166.0 vs 152.7 m) and s.c. adipocytes (166.7 vs 148.8 m) than NC heifers. Heifers implanted with zeranol at 56 and 146 d of age had a greater (P less than .03) uterine horn diameter and heavier (P less than .02) uterine weight than unimplanted heifers. Percentage of lipid in the udder was lower (P less than .02) in heifers implanted with zeranol. Implanted heifers had smaller (P less than .10) s.c. adipocytes than unimplanted heifers. Breed of dam did not effect (P greater than .17) development of the reproductive tract of weanling heifers. Heifers from Angus dams had smaller (P less than .08) udders and less (P less than .10) total fat in the udder than those from F1 dams, and the heifers from F1 dams tended (P less than .12) to have larger udder adipocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1989

Endodermal sinus tumor of the infant vagina treated exclusively by chemotherapy.

A 5-month-old Hispanic female, diagnosed as having endodermal sinus tumor of the vagina, was treated with combination chemotherapy in an attempt to preserve pelvic function. An incisional biopsy was performed before starting chemotherapy. After completion of chemotherapy, no residual disease was found at exploratory laparotomy. The patient received no further therapy and is disease-free 45 months later. This case represents successful treatment of a vaginal endodermal sinus tumor without any operative excision.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Anion-binding exosite of human alpha-thrombin and fibrin(ogen) recognition.

Activation of prothrombin to alpha-thrombin generates not only the catalytic site and associated regions but also an independent site (an exosite) which binds anionic substances, such as Amberlite CG-50 resin [cross-linked poly(methylacrylic acid)]. Like human alpha-thrombin with high fibrinogen clotting activity (peak elution at I = 0.40 +/- 0.01 M, pH 7.4, approximately 23 degrees C), catalytically inactivated forms (e.g., i-Pr2P-alpha- and D-Phe-Pro-Arg-CH2-alpha-thrombins) were eluted with only slightly lower salt concentrations (I = 0.36-0.39 M), while gamma-thrombin with very low clotting activity was eluted with much lower concentrations (I = 0.29 M) and the hirudin complex of alpha-thrombin was not retained by the resin. In a similar manner, hirudin complexes of alpha-, i-Pr2P-alpha-, and gamma-thrombin were not retained by nonpolymerized fibrin-agarose resin. Moreover, the ionic strengths for the elution from the CG-50 resin of seven thrombin forms were directly correlated with those from the fibrin resin (y = 0.15 + 0.96x, r = 0.95). In other experiments, the 17 through 27 synthetic peptide of the human fibrinogen A alpha chain was not an inhibitor of alpha-thrombin, while the NH2-terminal disulfide knot (NDSK) fragment was a simple competitive inhibitor of alpha-thrombin with a Ki approximately 3 microM (0.15 M NaCl, pH 7.3, approximately 23 degrees C). These data suggest that alpha-thrombin recognizes fibrin(ogen) by a negatively charged surface, noncontiguous with the A alpha cleavage site but found within the NDSK fragment. Such interaction involving an anion-binding exosite may explain the exceptional specificity of alpha-thrombin for the A alpha cleavage in fibrinogen and alpha-thrombin incorporation into fibrin clots.

Anions↗