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Biomedical subjects

J Olson

Publications and source records attributed to J Olson.

At least 91 records · Page 5Linked to original sources
PubMed1994

Work practices, fatigue, and nuclear power plant safety performance.

This paper focuses on work practices that may contribute to fatigue-induced performance decrements in the commercial nuclear power industry. Specifically, the amount of overtime worked by operations, technical, and maintenance personnel and the 12-h operator shift schedule are studied. Although overtime for all three job categories was fairly high at a number of plants, the analyses detected a clear statistical relationship only between operations overtime and plant safety performance. The results for the 12-h operator shift schedule were ambiguous. Although the 12-h operator shift schedule was correlated with operator error, it was not significantly related to the other five safety indicators. This research suggests that at least one of the existing work practices--the amount of operator overtime worked at some plants--represents a safety concern in this industry; however, further research is required before any definitive conclusions can be drawn.

Fatigue↗
PubMed1994

THE ONTOGENY OF SHIVERING THERMOGENESIS IN THE RED-WINGED BLACKBIRD (AGELAIUS PHOENICEUS)

The ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (Agelaius phoeniceus). Two indices of heat production ­ the rate of oxygen consumption (V(dot)O2) of the bird and the electromyographic (EMG) activity of the pectoralis (PECT) and gastrocnemius (GAST) muscles ­ were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient temperatures (Ta). The ontogenetic changes in both indices indicated that the capability for thermogenesis in nestling red-winged blackbirds improved markedly with age. The metabolic rates of 3-day-old nestlings decreased during exposure to gradually falling ambient temperatures; at best, these nestlings were only able to maintain mass-specific V(dot)O2 at levels similar to or slightly above the resting metabolic rate at thermoneutral temperatures (RMR) for a short time before metabolic rates decreased with further cooling. Shivering was detected only in the PECT muscles and was of a relatively low intensity (maximum of sevenfold increase in intensity over basal levels). The 5-day-old nestlings increased mass-specific V(dot)O2 modestly (approximately 1.4-fold) above RMR and attained slightly higher maximal factorial increases in the EMG activity of the PECT (maximum of 18-fold basal levels) when exposed to the same experimental conditions. Shivering was also detected in the GAST muscles of these birds. The most striking improvements in both measures observed during the nestling period occurred between day 5 and day 8. Eight-day-old nestlings increased metabolic rates by approximately 2- to 2.5-fold over basal levels and sustained these elevated rates for longer before becoming hypothermic. Both the PECT and GAST muscles contributed significantly to shivering thermogenesis, and these older nestlings attained much higher factorial increases in the intensity of shivering (up to 72-fold) during exposure to cold temperatures. In addition, both the range and magnitude of the dominant frequencies of muscle activity in the PECT increased during postnatal development. The PECT muscles were a principal site of shivering thermogenesis in all nestling and adult red-winged blackbirds studied here. Shivering in these muscles was a 'first line defense' against cold; the threshold temperature for shivering in the PECT muscles coincided with the lower critical temperature for oxygen consumption (TLC), and the subsequent increases in EMG activity in this muscle with further cooling correlated well with the corresponding increases in mass-specific V(dot)O2.

Journal Article↗
PubMed1994

The teamwork project: a collaborative approach to learning to nurse families.

The purpose of this exploratory study was to gain insight into students' perceptions of learning to nurse families using a team approach. A sample of 112 third-year baccalaureate nursing students provided data from clinical journals and responses to a teacher-developed questionnaire regarding number of home visits made with a partner, the extent to which partners shared responsibility for the nursing care of two families, perceived benefits and disadvantages of teamwork, roles assumed by team members, perceived outcomes of the team approach, and suggestions for revision of the approach. The degree to which students shared responsibility was moderate and positive perceptions of teamwork were significantly correlated with the degree of sharing of nursing activities. Using Spradley's qualitative method of domain analysis, interpretation of data from students' clinical journals revealed subjective aspects of the experience that appeared to influence teamwork practices and attitudes. Results suggest that the shared assignment approach offers students a unique opportunity to learn about the realities of collaborative nursing practice.

Attitude↗
PubMed1994

The use of umbilical cord blood in mismatched related and unrelated hemopoietic stem cell transplantation.

Over the past 6 years, umbilical cord blood has emerged as an efficacious alternative source of hematopoietic stem cells in related bone marrow transplantation. These encouraging results led us to extend this technology to the mismatched related and unrelated settings in three high-risk leukemic children lacking a matched-related donor for transplantation. Two of the three children also lacked identifiable donors through the National Marrow Donor Program, while the third was in relapse and did not have time to wait for completion of a search. The first child was transplanted with haploidentical umbilical cord blood-derived mononuclear cells from his sister, while the remaining two children were transplanted with partially mismatched, unseparated, unrelated umbilical cord blood banked through the Placental Blood Project at the New York Blood Center. All three children demonstrated trilineage engraftment with donor cells within 6 weeks of transplantation. The patient transplanted with haploidentical marrow developed grade 2 graft vs. host disease (GVHD), which was controlled with steroid and anti-thymocyte globulin (ATG) therapy. One of the two patients grafted with unrelated umbilical cord blood developed mild grade 1 GVHD of the skin, which rapidly cleared with steroid therapy. One patient remains alive, in good health and disease-free 12 months from transplantation.

Acute Disease↗
PubMed1993

Hippocampal serotonin levels influence the expression of S100 beta detected by immunocytochemistry.

The response of astrocytes to pharmacological alterations of the serotonin (5-HT) content of the dorsal area dentata was studied by immunocytochemistry for S100 beta. Stereological analysis revealed changes in the density of astrocytic elements in conditions of 5-HT depletion and elevated 5-HT levels. There was a direct relationship between the expression of S100 beta and the level of 5-HT in the hippocampal formation. Thus when 5-HT was reduced by PCPA treatment, S100 beta immunoreactivity was also reduced. The converse of these observations was obtained in cases where the 5-HT levels were increased by fluoxetine administration. These immunocytochemical data are consistent with previous reports of the response of astrocytes to 5-HT in vitro.

Animals↗
PubMed1993

Membrane protein topology determination by proteolysis of maltose binding protein fusions.

A method is presented for determining the topology of Escherichia coli inner membrane proteins that is based on proteolysis of fusion proteins between maltose binding protein (MBP) and the membrane protein of interest. Fusion proteins are constructed wherein the MBP domain is fused upstream of the membrane protein domain. A secreted MBP domain is attached to the protein if its N-terminus resides in the periplasm. A cytosolic MBP domain (MBP delta 2-26) is attached to the protein when its N-terminus resides in the cytoplasm. The method has been developed using a fusion protein in which a secreted MBP domain is attached to the pBR322 tetracycline resistance protein at its first periplasmic loop. Fusion proteins are subjected to partial proteolysis in membrane vesicles under conditions where digestion does not occur in MBP. The mixture of digestion products is analyzed by Western immunoblotting using anti-MBP antiserum to detect cleavage fragments. Sites of digestion in the membrane protein are identified by comparing the mobilities of digestion products to truncated fusion standards that terminate at defined locations within the membrane protein domain. The technique has the advantage that neither overexpression of the protein nor high-quality antiserum to it are required for detection of protease fragments. Furthermore, the method can be applied to screen membrane proteins for structure alterations that have been introduced deliberately into them.

ATP-Binding Cassette Transporters↗
PubMed1993

Serum biochemical changes in dogs competing in a long-distance sled race.

Fifty-five blood samples were collected from 28 dogs competing in the 1991 Yukon Quest International Sled-Dog Race to examine race-induced changes in serum biochemical values. Blood was collected after a 36-hour mandatory rest at the midpoint of the race, and again at 2 subsequent checkpoints. The mean speed of dogs between checkpoints was approximately 4.5 mph. There were no significant increases in PCV, or in serum total protein, sodium, or creatinine concentrations during the race. Mean serum potassium concentration decreased significantly (P < 0.05) from 4.8 +/- 0.4 to 4.4 +/- 0.3 to 3.9 +/- 0.3 mEq/L, as did the serum triglyceride concentration (138 +/- 52, 88 +/- 25, 81 +/- 16 mg/dl). Plasma cortisol concentration did not change significantly. Increases in the mean serum activity of creatine kinase (167, 420, 344 U/L), and aspartate aminotransferase (55, 79, 62 U/L) during the race were significant (P < 0.05). Participation in a long-distance sled race was associated with mild changes in routinely measured serum biochemical values in dogs.

Animals↗
PubMed1993

Lack of association between free testosterone and bone density separate from age in elderly males.

It is unclear what proportion of the variance in bone density in elderly males is accounted for by testosterone status. We studied 112 ambulatory, elderly volunteers (mean age 71.7 years) and determined free testosterone (FT), as well as bone density measurements by photon absorptiometry at multiple sites. Our studies of 35 of these subjects 4 years later included morning FT and dual energy X-ray absorptiometry. There were no significant correlations between FT and bone density at multiple scanning sites with the effects of age partialed out. We suspect that our inability to detect a significant effect of FT on bone density was related to the relative strength of other determinants of bone density, as well as to the fact that FT values are far more dynamic than bone density.

Absorptiometry, Photon↗
PubMed1993

Enzyme-linked immunosorbent assay for detection of human immunoglobulin G to lipopolysaccharide of spotted fever group rickettsiae.

An enzyme-linked immunosorbent assay for detecting human immunoglobulin G to spotted fever group rickettsiae was developed and tested. The assay uses proteinase K-resistant material, characteristic of the rickettsial lipopolysaccharides shown to be group specific by immunoblots, as the antigen. The results indicate that the assay provides a sensitive, yet specific, alternative method for diagnosing rickettsial diseases.

Endopeptidase K↗
PubMed1993

Community-based prevalence profile of arboviral, rickettsial, and Hantaan-like viral antibody in the Nile River Delta of Egypt.

To determine the current prevalence of antibody to arboviruses, rickettsiae, and hantaan-like viruses, a survey was carried out in the Nile River Valley of Egypt, one of the principal foci of the 1977-1978 Rift Valley fever (RVF) outbreak. Blood specimens were obtained from 915 persons representing 190 study households. Enzyme immunoassay testing showed that the overall prevalence of IgG antibody was 4% to sand fly fever Sicilian (SFS), 2% to sandfly fever Naples (SFN), 15% to RVF, 20% to West Nile, and 4% to Hantaan (HTN) viruses. Antibody was demonstrated among 32% of the same study subjects to Coxiella burnetii, 58% to Rickettsia typhi, and 32% to R. conorii. The prevalence of agent-specific antibody tended to increase with age. Particularly notable was the low prevalence of RVF infection in children born after the height of the RVF outbreak. No detectable antibodies were found in the population less than seven years of age and in only 3% of those 7-12 years old. In contrast, 26% of the study population 13-19 years old, who were young children and infants at the time of the outbreak, were found to have RVF antibodies, suggesting that the level of intensity associated with transmission decreased considerably following the documented 1977-1978 outbreak. Geometric mean titers (GMT) ranged from 139 for C. burnetii to 1,305 for RVF, and did not vary significantly by age, except for high titers for RVF in the 20-49-year-old age group. A significant upward trend in GMT was also noted when antibody was detected in the specimen for more than one phlebovirus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Reaching out: bringing the human factor back to dialysis.

Prior to the early 1980s, two Winnipeg hospitals provided hemodialysis for all patients in Manitoba with chronic renal failure. Because no other hemodialysis centres existed, families were forced to relocate to the city. Because of these factors, the Manitoba Renal Failure Advisory Committee proposed the development of an outreach hemodialysis program. Under the auspices of the Health Sciences Centre in Winnipeg, this outreach program has evolved into the current Manitoba Local Centre Dialysis Program. Hemodialysis services are now available in an additional seven health care centres throughout Manitoba and northwestern Ontario. This program has benefited many and in some instances, families previously separated by distances of up to 500 miles have been reunited. Creativity has been one of the most essential ingredients in the evolution of this unique program.

Hemodialysis, Home↗
PubMed1992

Psychosocial factors and immune senescence in the aged primate.

With increasing age, old animals and humans show decreases in a number of immune responses indicative of the process of immune senescence. Our studies investigated whether social companionship, as a potentially positive psychological intervention, would increase lymphocyte proliferation and natural killer cell activity in the aged nonhuman primate. Contrary to our initial hypothesis, social stimulation resulted in decreased immune responses in old monkeys. With specific modifications of the housing conditions it was possible to prevent these decreases in immune responses from occurring, but social companionship still failed to enhance immune responses in the aged monkey.

Aging↗
PubMed1992

Polysomnographic and clinical findings in children with obstructive sleep apnea.

A retrospective study was conducted to determine which types of children might have polysomnographic findings that are most compatible with obstructive sleep apnea (OSA). The charts of 93 patients who were aged 18 months to 12 years were examined. All 93 patients had symptoms that were initially suggestive of OSA, and they underwent polysomnography. The types of presenting symptoms and associated illnesses were noted. Physical findings, including height, weight, and tonsil size, were examined. Of 93 patients with symptoms that were suggestive of OSA, 34 met sleep study criteria for OSA. In 44 patients, OSA was not demonstrated, and 15 patients had other results. On the basis of age, sex, and symptoms, no significant differences could be found between the group with OSA and the group with normal polysomnographic findings. Cor pulmonale, tonsil hypertrophy, and failure to thrive were associated with OSA. Surprisingly, obesity was not significantly associated with OSA.

Child↗
PubMed1992

Tumor markers CA 19-9 and CA 195 are also useful as markers for cystic fibrosis.

When monoclonal kits are used we can no longer detect highly elevated serum concentrations of carcinoembryonic antigen in cystic fibrosis (CF) patients as we could earlier (Pediatr Res 10:223-236, 1975). Instead, we find increased concentrations of CA 19-9 or CA 195 in the CF sera. The serum levels of CA 19-9 not only reflect the pulmonary condition of CF patients but also respond well to antibiotic therapy. Several lines of evidence suggest that the elevated serum concentration of CA 19-9 is derived from sputum and corresponds with the amount of sputum in the lung. Correlations between CA 19-9 and CA 195 in random and serial specimens from both patients with CF and patients with pancreatic carcinoma suggest that all sera contain heterogeneous, Lewis blood group-related epitopes and the proportions of various epitopes are different among individual patients. When monitored on multiple tumor markers, the pattern of CF is different from that of pancreatic carcinoma although both usually show elevated CA 19-9. Our study indicates that both CA 19-9 and CA 195 can be used as sensitive markers for the early detection of exacerbation in CF patients.

Adolescent↗
PubMed1992

Intravenous and oral zidovudine pharmacokinetics and coagulation effects in asymptomatic human immunodeficiency virus-infected hemophilia patients.

Pharmacokinetic and coagulation studies were carried out over a 12-week period with 11 asymptomatic hemophilia patients with human immunodeficiency virus infection receiving zidovudine (ZDV). The patients received 300 mg every 4 h while awake (the accepted dose at the time of this study); consecutive 24-h intravenous (i.v.) and 12-h oral pharmacokinetic studies were conducted at weeks 1, 6, and 12. Coagulation studies were conducted at weeks 0, 4, 8, and 12. The numbers of units of factors VIII and IX and cryoprecipitate transfused during the 12-week periods before, during, and after ZDV treatment were recorded. Following i.v. and oral ZDV administration, the concentration in plasma declined rapidly over the first 4 h, and in some patients, ZDV was still detectable at 4 to 10 h. The i.v. total clearances (means +/- standard deviations) were 14.9 +/- 7.3, 11.2 +/- 3.7, and 15.1 +/- 4.7 ml/min/kg of body weight. The i.v. distribution volumes were 1.08 +/- 0.5, 1.0 +/- 0.4, and 1.65 +/- 1.4 liters/kg. The bioavailabilities were 0.54 +/- 0.22, 0.46 +/- 0.19, and 0.59 +/- 0.13 at weeks 1, 6, and 12, respectively. The pattern of ZDV-glucuronide (GZDV) disposition was similar to that of ZDV, and the peak plasma GZDV-to-ZDV ratio was higher after oral dosing, consistent with first-pass metabolism. In some individuals, up to 33% of an i.v. dose was excreted unchanged. At weeks 6 and 12, greater than 300 mg of total ZDV (GZDV plus ZDV) was recovered in the urine of some patients, suggesting tissue redistribution. Concentration in plasma after oral ZDV administration were variable, both within and between patients. The von Willebrand antigen level consistently decreased throughout the study but was not accompanied by a parallel change in ristocetin cofactor A activity, and no clinical adverse effects on coagulation were noted. This study demonstrates that ZDV can be used in hemophilia patients without worsening of their bleeding tendencies. The clinical significance of decreased ZDV clearance and the prolonged terminal elimination phase of ZDV will require further study with patients receiving chronic ZDV.

Administration, Oral↗