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Biomedical subjects

T Olson

Publications and source records attributed to T Olson.

At least 19 recordsLinked to original sources
PubMed2005

Effects of colesevelam HC1 on sterol and bile acid excretion in patients with type IIa hypercholesterolemia.

Colesevelam HC1 is a potent bile acid-binding polymer. This study's aim was to determine effects of colesevelam HCl on sterol and bile acid excretion in patients with type IIa hypercholesterolemia. Twenty-four patients (low-density lipoprotein cholesterol, 130 to 220 mg/dL) enrolled in an open-label, parallel-design study, entered an American Heart Association/National Cholesterol Education Program diet for 6 weeks and were randomized to colesevelam HCl, 2.3 or 3.8 g/day for 4 weeks. In an apparent dose-related manner, respective mean serum concentrations HCl of low-density lipoprotein cholesterol decreased by 10% (P < 0.01) and 13% (P = 0.05), mean total cholesterol levels decreased by 4.9% (P = 0.05) and 6.1% (P = 0.09), and total fecal bile acid excretion showed median changes of +324% (P < 0.05) and +316% (P < 0.05). Colesevelam HCl did not affect fecal neutral sterol or fecal fatty acid excretion; however, 24-hr urinary mevalonic acid levels significantly increased in both treatment groups (P < 0.05). The cholesterol-lowering action of colesevelam HCl appears to be mediated through increased bile acid excretion.

Allylamine↗
PubMed2004

Outcome and staging evaluation in malignant germ cell tumors of the ovary in children and adolescents: an intergroup study.

PURPOSE: The aim of this study was to perform an evaluation of outcome and the role of surgical staging components in malignant germ cell tumors (GCT) of the ovary in children and adolescents. METHODS: From 1990 to 1996, 2 intergroup trials for malignant GCT were undertaken by Pediatric Oncology Group (POG) and Children's Cancer Study Group (CCG). Stage I-II patients were treated with surgical resection and 4 cycles of standard dose cisplatin (100 mg/m2/cycle), etoposide, and bleomycin (PEB) chemotherapy. Stage III-IV patients were treated with surgical resection and randomly assigned to chemotherapy with PEB or high-dose cisplatin (200 mg/m2/cycle) with etoposide and bleomycin (HDPEB). Patients unresectable at diagnosis had second-look operation after 4 cycles of chemotherapy if residual tumor was seen on imaging studies. IRB approval of the protocols was obtained at each participating institution. An analysis of outcome data, operative notes, and pathology reports in girls with ovarian primary site was done for this report. RESULTS: There were 131 patients with ovarian primary tumors of 515 entered on these studies. Mean age was 11.9 years (range, 1.4 to 20 years). Six-year survival rate was stage, I 95.1%; stage II, 93.8%; stage III, 98.3%; stage IV, 93.3%. In only 3 of 131 patients were surgical guidelines followed completely. Surgical omissions resulting in protocol noncompliance resulted from failure to biopsy bilateral nodes (97%), no omentectomy (36%), no peritoneal cytology (21%), no contralateral ovary biopsy (59%). More aggressive procedure than recommended by guidelines included total hysterectomy and bilateral salpingo-oophorectomy in 6 patients and retroperitoneal node dissection in 10 patients. Correlation of gross operative findings with pathology results was carried out for ascites, lymph nodes, implants, omentum, and contralateral ovary. CONCLUSIONS: Pediatric ovarian malignant GCT (stages I-IV) have excellent survival with conservative surgical resection and platinum-based chemotherapy. Survival appears to have been unaffected by deviations from surgical guidelines. New surgical guidelines are proposed based on correlation of gross findings, histology, and outcome in these intergroup trials.

Adolescent↗
PubMed2002

Resuspension of DNA sequencing reaction products in agarose increases sequence quality on an automated sequencer.

We are investigating approaches to increase DNA sequencing quality. Since a majorfactor in sequence generation is the cost of reagents and sample preparations, we have developed and optimized methods to sequence directly plasmid DNA isolated from alkaline lysis preparations. These methods remove the costly PCR and post-sequencing purification steps but can result in low sequence quality when using standard resuspension protocols on some sequencing platforms. This work outlines a simple, robust, and inexpensive resuspension protocol for DNA sequencing to correct this shortcoming. Resuspending the sequenced products in agarose before electrophoresis results in a substantial and reproducible increase in sequence quality and read length over resuspension in deionized water and has allowed us to use the aforementioned sample preparation methods to cut considerably the overall sequencing costs without sacrificing sequence quality. We demonstrate that resuspension of unpurified sequence products generated from template DNA isolated by a modified alkaline lysis technique in low concentrations of agarose yields a 384% improvement in sequence quality compared to resuspension in deionized water. Utilizing this protocol, we have produced more than 74,000 high-quality, long-read-length sequences from plasmid DNA template on the MegaBACET 1000 platform.

Cell Fractionation↗
PubMed2001

Multipoint imprinting analysis indicates a common precursor cell for gonadal and nongonadal pediatric germ cell tumors.

Pediatric germ cell tumors (GCTs) commonly arise at extragonadal sites. It has been proposed that nongonadal GCTs arise from ectopic primordial germ cells that have aberrantly migrated during embryogenesis. During a time between their migration and development to mature gametes, primordial germ cells are characterized by their lack of imprinting, which can be assessed by the evaluation of allelic gene expression and DNA methylation in differentially methylated control regions. To elucidate the cellular origin of nongonadal GCTs, we evaluated the imprinting status of 21 gonadal and 21 nongonadal pediatric GCTs. Allele-specific H19 and IGF-2 expression was assessed with reverse transcription-PCR followed by digestion at polymorphic restriction sites. DNA methylation was evaluated after bisulfite modification, PCR amplification, and restriction digestion at a consistently methylated CpG dinucleotide within the 5' flanking region of the SNRPN gene. These results were compared with genetic gains and losses determined by comparative genomic hybridization. Seven of 15 informative tumors showed biallelic H19 expression, and 8 of 17 informative tumors showed biallelic IGF-2 expression. The frequency of biallelic gene expression was comparable in gonadal and nongonadal GCTs. Sixteen of 19 gonadal GCTs and 17 of 21 nongonadal GCTs showed absence of methylation of SNRPN consistent with loss of imprinting. One testicular GCT and three nongonadal GCTs showed a somatic methylation pattern. Two ovarian teratomas and one mediastinal teratoma showed only methylated SNRPN, consistent with entry into meiosis. Twenty-one of 22 non-GCT control samples showed a somatic methylation pattern. Gonadal and nongonadal germ cell tumors are derived from primordial germ cells that have consistently lost the imprinting of SNRPN and partly lost imprinting of H19 and IGF-2. Because the imprinting pattern of the latter genes differs from that found in testicular GCTs of adult patients, our data suggest that pediatric GCTs arise from a different stage of germ cell development.

Adolescent↗
PubMed2001

Physiological patterns during practice of the Transcendental Meditation technique compared with patterns while reading Sanskrit and a modern language.

This study tested the prediction that reading Vedic Sanskrit texts, without knowledge of their meaning, produces a distinct physiological state. We measured EEG, breath rate, heart rate, and skin conductance during: (1) 15-min Transcendental Meditation (TM) practice; (2) 15-min reading verses of the Bhagavad Gita in Sanskrit; and (3) 15-min reading the same verses translated in German, Spanish, or French. The two reading conditions were randomly counterbalanced, and subjects filled out experience forms between each block to reduce carryover effects. Skin conductance levels significantly decreased during both reading Sanskrit and TM practice, and increased slightly during reading a modern language. Alpha power and coherence were significantly higher when reading Sanskrit and during TM practice, compared to reading modern languages. Similar physiological patterns when reading Sanskrit and during practice of the TM technique suggests that the state gained during TM practice may be integrated with active mental processes by reading Sanskrit.

Adult↗
PubMed2000

Glyphosate-tolerant corn: the composition and feeding value of grain from glyphosate-tolerant corn is equivalent to that of conventional corn (Zea mays L.).

Glyphosate-tolerant (Roundup Ready) corn line GA21 has been developed by genetic modification to tolerate glyphosate, the active ingredient in Roundup herbicide. The purpose of this study was to evaluate the compositional and nutritional safety of corn line GA21 compared to that of conventional corn. Compositional analyses were conducted to measure proximate, fiber, amino acid, fatty acid, and mineral contents of grain and proximate, fiber, and mineral contents of forage collected from 16 field sites over two growing seasons. The nutritional safety of corn line GA21 was evaluated in a poultry feeding study conducted with 2-day old, rapidly growing broiler chickens, at a dietary concentration of 50-60% w/w. Compositional analysis results showed that, except for a few minor differences that are unlikely to be of biological significance, the grain and forage of GA21 corn were comparable in their composition to that of the control corn line and to conventional corn. Results from the poultry feeding study showed that there were no differences in growth, feed efficiency, adjusted feed efficiency, and fat pad weights between chickens fed with GA21 grain or with parental control grain. These data taken together demonstrate that Roundup Ready corn is as safe and nutritious as conventional corn for food and feed use.

Amino Acids↗
PubMed2000

Compositional analysis of tubers from insect and virus resistant potato plants.

Genetically modified potato plants that are resistant to the Colorado potato beetle, plus either the potato leaf roll virus or potato virus Y, have recently been commercialized. As part of the safety assessment for plants produced by modern biotechnology, the composition of the food/feed must be compared to that of the food/feed produced by an equivalent plant variety from a conventional source. The composition of important nutritional and antinutritional factors in tubers produced by virus- and insect-resistant potato plants were compared to tubers produced by conventional potato plants. Key nutritional, quality, and antinutritional components measured were total solids, vitamin C, dextrose, sucrose, soluble protein, and glycoalkaloids. Proximate analyses included fat, ash, calories, total protein, and crude fiber. Minor nutrients measured were vitamin B6, niacin, copper, magnesium, potassium, and amino acids. The results from these analyses confirm that tubers produced by insect- and virus-protected varieties are substantially equivalent to tubers produced by conventional potato varieties.

Animals↗
PubMed1998

Chart audit of inpatient treatment of schizophrenic patients: implications for development of coordinated care paths.

This study offers important information regarding the standard of care provided to schizophrenic patients treated at one inpatient facility. The findings were particularly useful in the development of a care path for this specific population. Areas for improvement identified in this research include medical tests, master treatment planning, documentation of care, patient teaching, and discharge planning. Given the limited health care dollars and the lack of a cure for schizophrenia, this research emphasizes the fact that treatment guidelines need to be aggressively tested as to their relevance to practice.

Adult↗
PubMed1997

Development of a scientifically valid coordinated care path.

OBJECTIVE: The goal of this study was to develop a method to scientifically create and validate a coordinated care path for use within any hospital setting. BACKGROUND: In an attempt to reduce the costs associated with high-volume and high-risk diagnosis, attention was focused on reducing patients' length of stay in the hospital. A method to reduce length of stay uses a coordinated care path. A path is a guideline used to manage the clinical care of selected patients. The literature is relatively silent regarding studies that have scientifically validated the use of these paths. METHODS: This project used a content validity method to validate the care path. Using current research findings, best practice standards both locally and nationally, a transdisciplinary team developed practice guidelines that included sequencing, timing of interventions, and expected patient outcomes. The path was rated by local and national experts using a four-point rating scale. Using Lynn's proportion of experts table computations, the validity of the path and each of its components was determined. RESULTS: Of 161 items on the care path, 10 were not validated. The experts validated the instrument as a whole. Of the 161 items, 151 were validated. This is an instrument validation rate of 0.94. No additional changes or modifications to the path were suggested by the experts. The transdisciplinary team addressed the nonvalidated items. This method can be used to develop other coordinated paths for other diagnostic groups.

Critical Pathways↗
PubMed1996

Stem cell factor (SCF) synergizes with megakaryocyte colony stimulating activity in post-irradiated aplastic plasma in stimulating human megakaryocytopoiesis.

Plasma obtained from lethally irradiated animals contains a megakaryocyte (MK) growth factor which has recently been identified as the ligand for the c-mpl receptor and has been named thrombopoietin (TPO). We demonstrate that post-irradiation aplastic canine plasma (PICS-J) and plasma from a human subject (ML) who was accidentally exposed to lethal irradiation, contain high levels of this activity, which support both MK proliferation and maturation in a dose-dependent manner. These plasma were far more active in stimulating human MK colony formation than other types of thrombocytopenic plasma or a number of exogenously added human recombinant cytokines and their combinations. The addition of stem cell factor (SCF), which alone has a minimal stimulatory affect, to post lethal-irradiation plasma provided a synergistic stimulation of megakaryocytopoiesis both in colony assays and liquid cultures. In colony assays, the combination of SCF with PICS-J or ML almost doubled the number of burst forming units (BFU-MK) and provided a 1.5-fold increase in colony forming units (CFU-MK). A 1.6-fold increase in the number of CD34+ BM cell-derived MK colonies was also elicited. In liquid cultures, the presence of both SCF and PICS-J or ML induced the appearance of a high proportion of CD34+ (6.56% vs 0.6% control) and CD41+ (3.5% vs 1.2% control) cells after 3 days in culture. By day 10, 66.8 x 10(4) CD41+ cells and 29.8 x 10(4) CD34+ cells were derived from 2 x 10(6) BMMC originally seeded. We propose that these unique plasma, which do not contain elevated level of IL-6, IL-3, GM-CSF, IL-1 beta, erythropoietin or SCF, probably contain high levels of TPO. The addition of SCF to the post-irradiation plasma provides a synergistic stimulation of megakaryocytopoiesis which may become relevant for future clinical application.

Anemia, Aplastic↗
PubMed1996

Fundamental and special: the dilemma of psychiatric-mental health nursing.

This article explores the tension between defining psychiatric-mental health nursing as fundamental to the discipline yet also special, an historic dilemma that continues to influence efforts to establish a secure place for the specialty. Analysis focuses on the formative work of three pioneers in this field, using primary and secondary documents in the archives of the Center for The Study of The History of Nursing. The findings of this research indicate that early reliance on interpersonal theory provided an uncertain basis for differentiating psychiatric-mental health nursing from other areas of nursing practice.

History, 20th Century↗
PubMed1996

Genome duplication in soybean (Glycine subgenus soja).

Restriction fragment length polymorphism mapping data from nine populations (Glycine max x G. soja and G. max x G. max) of the Glycine subgenus soja genome led to the identification of many duplicated segments of the genome. Linkage groups contained up to 33 markers that were duplicated on other linkage groups. The size of homoeologous regions ranged from 1.5 to 106.4 cM, with an average size of 45.3 cM. We observed segments in the soybean genome that were present in as many as six copies with an average of 2.55 duplications per segment. The presence of nested duplications suggests that at least one of the original genomes may have undergone an additional round of tetraploidization. Tetraploidization, along with large internal duplications, accounts for the highly duplicated nature of the genome of the subgenus. Quantitative trait loci for seed protein and oil showed correspondence across homoeologous regions, suggesting that the genes or gene families contributing to seed composition have retained similar functions throughout the evolution of the chromosomes.

Chromosome Mapping↗
PubMed1995

A novel method to purify recombinant vascular endothelial growth factor (VEGF121) expressed in yeast.

VEGF is a potent mitogen for vascular endothelial cells in vitro and acts as an angiogenic factor in vivo. VEGF121 differs from the other isoforms in that it lacks the heparin-binding domain. To study the potential differences in biological functions of the VEGF isoforms, we cloned and expressed VEGF121 in a yeast expression system. VEGF121 was secreted from the yeast cells as a homodimer with a molecular weight of 34-36 kDa. By taking advantage of the consecutive histidine residues present at position 11 and 12 in VEGF, a novel method of purification using Nickel affinity chromatography was developed. Since all the isoforms of VEGF have an identical amino terminal end, this method can be used to purify not only VEGF121 but also the other forms of VEGF. The level of expression achieved using this system was as high as 40 mg/L. The recombinant protein was biologically active in stimulating the in vitro proliferation of vascular endothelial cells and positively reacted to an antiserum made against recombinant VEGF165.

Cell Division↗
PubMed1995

Transferrin-antibody fusion proteins are effective in brain targeting.

In the present study, the receptor binding potential of transferrin (Tf) was linked to an antibody binding specificity. Human Tf was fused to mouse-human chimeric IgG3 at three positions: at the end of heavy chain constant region 1 (CH1), after the hinge, and after CH3. The resulting Tf-antibody fusion proteins were able to bind antigen and the Tf receptor. The CH3-Tf fusion protein showed no complement-mediated cytolysis but possessed IgG receptor I (Fc gamma RI) binding activity. Most importantly, all of the fusion proteins demonstrated significant uptake into brain parenchyma, with 0.3% of the injected dose of the hinge-Tf fusion protein rapidly targeted to the brain. Recovery of iodinated CH3-Tf fusion protein from the brain parenchyma demonstrated that the fusion proteins can cross the blood-brain barrier intact. The binding specificity of these fusion proteins can be used for brain delivery of noncovalently bound ligands, such as drugs and peptides, or for targeting antigens present within the brain.

Animals↗
PubMed1995

High-dose-rate brachytherapy in childhood sarcomas: a local control strategy preserving bone growth and function.

The administration of external beam radiation therapy (EBRT) has been an integral part of the successful treatment of childhood sarcomas. However, EBRT has severe late morbidity in the developing child. In an attempt to deliver adequate tumoricidal radiation while preserving bone growth and organ function, 13 children with diverse sarcomas were treated with high dose rate brachytherapy (HDR). Seven patients had rhabdomyosarcoma and six patients had other soft tissue sarcoma variants. All patients were treated with disease-appropriate chemotherapy, usually according to the intergroup Rhabdomyosarcoma Study. Eleven patients received fractionated 36 Gy HDR alone at a mean of 3.5 months from diagnosis. Two patients received 10-12.5 Gy intraoperative HDR brachytherapy and additional 27 Gy EBRT. Nine of 11 patients in first remission have had no recurrences. One died of recurrent pulmonary metastases. The other patient that did recur is disease-free 21 months post-recurrence. Two additional patients were treated with HDR after tumor recurrence. One patient with recurrent Ewing's sarcoma, relapsed and died. The second is disease free 3 months after autologous bone marrow transplant. Grade 1 morbidity occurred in 46%, Grade 2 in 15%, and Grade 3 in 8% of the children, while relatively good bone and organ growth was maintained. The combination of conservative surgery, chemotherapy, and HDR offers the potential for disease control in young children while preserving bone growth and organ function.

Brachytherapy↗
PubMed1995

Expression of biologically active human vascular endothelial growth factor in yeast.

Vascular endothelial growth factor (VEGF) is a glycoprotein consisting of two identical polypeptide chains linked by a disulfide bond. The unique biological activities of VEGF include its potent mitogenic and permeability inducing properties specific for the vascular endothelium. VEGF is implicated in tumor angiogenesis, wound healing, and the stimulation of collateral vessel formation at the site of arterial occlusion. Therefore, in order to produce large quantities of biologically active VEGF, a splice variant (VEGF165) was cloned and expressed in a yeast expression system. The coding region of VEGF165 was isolated from U937 cells by RT-PCR, sequenced and then cloned into the yeast expression vector pHILS1. VEGF165 was secreted into the medium as a dimer. Recombinant VEGF reacted to antibodies raised against the N-terminal and C-terminal synthetic polypeptides of human VEGF. As much as 35-40 mg/L of purified VEGF could be obtained from the yeast expression system. The recombinant protein was biologically active in inducing vascular endothelial cell proliferation in vitro and permeability changes in vivo.

Amino Acid Sequence↗
PubMed1990

Competing paradigms and the St Luke's Alumnae Association minutes, 1895-1916.

This study was designed to explore the relationship between the minutes of the alumnae association of a training school for nurses, from 1895 to 1916, and the occupational evolution of nursing. The members of the St Luke's Alumnae Association, even in their initial statement of purpose, consistently affirmed their ties to other nurses, thus implicitly supporting the cause of trained nursing. But the cause of trained nursing was not the same as that of professional nursing. These findings support the usefulness of the "work group" paradigm vs the paradigm of professionalization in attempting to describe accurately the occupational evolution of nursing as portrayed in the minutes.

Documentation↗