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Biomedical subjects

L D Nelson

Publications and source records attributed to L D Nelson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Antibody response of calves to immunoaffinity-purified bovine respiratory syncytial virus VP70 after vaccination and challenge exposure.

Immunoaffinity-purified bovine respiratory syncytial virus (BRSV) fusion (F) protein elicited anti-BRSV-specific antibody responses in BRSV-seronegative calves. After primary vaccination, all calves seroconverted to BRSV as determined by the virus neutralization (VN) test and developed anti-F protein antibodies detectable by protein immunoblot analyses. Subsequent vaccinations induced greater than twofold increase in VN titer in 3 of 9 (33%) calves, and 1 calf became VN-negative, but still had nonneutralizing antibody detectable by protein immunoblot analysis. This calf remained seronegative after challenge exposure. Two groups of calves were vaccinated IM with immunoaffinity-purified BRSV F protein. Each dose was 2 ml containing 20 micrograms of purified F protein. Freund's adjuvants were used for all vaccinations, with Freund's complete adjuvant used for the primary vaccination and Freund's incomplete adjuvant for subsequent vaccinations. The vaccine was administered to both groups at weeks 0 and 3; the first group received a third vaccination at weeks 21. Group-1 and -2 vaccinated calves and non-vaccinated contact controls were intranasally aerosol challenge-exposed with low cell culture-passage BRSV on weeks 22 and 9, respectively. Eight of 9 vaccinated calves did not develop a humoral anamnestic response following challenge exposure, as demonstrated by VN test and protein immunoblot analyses. Calf 14 from group 1 which had a 1:2 VN antibody titer prior to vaccination, was the only calf that developed an anamnestic response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

2-Hydroxydesipramine and desipramine plasma levels and electrocardiographic effects in depressed younger adults.

Desipramine was given to 34 outpatients aged 20 to 51 years who had primary major depressive disorder but who were otherwise in good health. Daily dosage at bedtime was constant for the final 3 weeks of the 5-week study (mean, [SD] 169.1 [46.1] mg). Electrocardiograms done predrug and after 5 weeks were read by a cardiologist blind to the order in which they were performed. Plasma samples drawn 14 hours after the final study dose were assayed by high performance liquid chromatography; mean (SD) levels were 140.2 (140.0) ng/ml for desipramine and 56.5 (29.4) ng/ml for 2-hydroxydesipramine (2-OH-DMI). Heart rate and PR, QRS and QTc intervals were significantly greater at the end of the study than at baseline, while QT intervals were significantly less. Changes in heart rate and PR, QT and QTc intervals were significantly negatively correlated with the value of the respective cardiac parameters at baseline. Changes in PR interval were significantly positively correlated with log desipramine, log 2-OH-DMI and log (desipramine + 2-OH-DMI). Stepwise multiple regression analyses showed that, for PR interval, each of the three plasma level variables showed a significant ability to improve R2 over that obtained from baseline PR alone. These findings suggest that both 2-OH-DMI and desipramine plasma levels predict a prolongation of intracardiac conduction in younger adults and that monitoring both levels may be useful in the clinical management of certain younger adult patients.

Adult↗
PubMed1990

Evaluation of APACHE II for cost containment and quality assurance.

APACHE II (an acronym formed from acute physiology score and chronic health evaluation) has been proposed to limit intensive care unit (ICU) admissions ('cost containment') and to judge outcome ('quality assurance') of surgical patients. To judge its performance, a 6-month study of 372 surgical ICU patients was performed. When patients were divided by mean duration of stay, mortality rates rose from 1% (short stay) to 19% (long stay) (p less than 0.001) for patients with APACHE II scores less than 10, but decreased from 94% (short stay) to 60% (long stay) (p less than 0.01) for patients with APACHE II scores more than 24. Exclusion of patients by high or low APACHE scores would 'save' 6% of ICU days but risk increasing morbidity, hospital costs, and deaths. Grouped APACHE II scores did not correlate with total hospital charges (r = 0.05, p = 0.89) or ICU days used (r = 0.42, p = 0.17). Grouping by APACHE II score and duration of ICU stay showed neither symmetry nor uniformity of mortality rates. Surgical patients would not be well served by APACHE II for quality assurance or cost containment.

Adult↗
PubMed1990

Use of recombinant human erythropoietin (r-HuEPO) in a Jehovah's Witness refusing transfusion of blood products: case report.

Recombinant human erythropoietin (r-HuEPO) administration to a Jehovah's witness refusing blood transfusions increased her nadir packed cell volume from 13% to 37% and reticulocyte count from 2% to 17.7%. R-HuEPO may provide an alternative safe and effective therapy in life-threatening anemia when blood transfusions are unacceptable to the patient.

Accidents, Traffic↗
PubMed1989

Errors in estimating energy expenditure in critically ill surgical patients.

Thirty-one critically ill surgical patients were receiving central parenteral nutrition. All were intubated, and 29 were receiving mechanical ventilatory support. Nutritional and metabolic data were recorded at the time of indirect calorimetry. Measured energy expenditure (MEE) was compared with predictions of basal energy expenditure (BEE) and calculated energy expenditure, defined as the product of BEE and a stress factor estimated by the nutrition support service to account for severity of illness and activity. The MEE was significantly greater than the BEE and significantly less than the calculated energy expenditure. The estimated stress factor was significantly greater than the actual MEE/BEE ratio, and the correlation between these values was poor. Clinical assessment may overestimate energy expenditure in critically ill patients because of the apparent degree of illness used to determine the stress factor. Bedside indirect calorimetry may be useful to assess more accurately energy expenditure and optimize nutritional support.

Adolescent↗
PubMed1989

Physiologic effects of steep positioning in the surgical intensive care unit.

Ten hemodynamically stable patients requiring mechanical ventilation for radiographically symmetric acute lung disease were studied during steep lateral positioning and continuous rotation in a Roto Rest kinetic treatment bed. There were no significant hemodynamic or ventilatory differences among the four positions (supine, right side down, left side down, and rotating). In four patients, arterial oxygen pressure (PaO2) decreased 16% to 49% in the lateral position when compared with the supine position. Continuous rotation restored the PaO2 toward the supine value in each patient. In six patients, PaO2 increased 11% to 35% during lateral positioning. In five of the six patients, the increase in PaO2 differed between sides, suggesting asymmetric lung disease. Continuous rotation did not significantly alter the PaO2 from the supine values in these patients. Adverse effects on oxygenation caused by positional changes may be reversed by continuous rotation using the Roto Rest kinetic bed.

Adult↗
PubMed1987

Titrating positive end-expiratory pressure therapy in patients with early, moderate arterial hypoxemia.

A prospective randomized study to compare two physiologic end-points for titrating positive end-expiratory pressure (PEEP) was performed in patients with early, moderate arterial hypoxemia after surgery or trauma. All patients initially received 5 cm H2O of PEEP. In group 1 patients, PEEP was increased only if PaO2 decreased below 65 torr on an inspired oxygen fraction (FIO2) of 0.45. PEEP was then added in 2- to 3-cm H2O increments until PaO2 again was above 65 torr. Group 2 patients were treated with incremental PEEP until the PaO2/FIO2 ratio was greater than 300 or physiologic shunt (Qsp/Qt) was less than 0.20. All therapy other than PEEP was similar in the two groups. There were no statistically significant differences in entry PaO2 (mean 85 +/- 11 [SD] and 87 +/- 11 torr in groups 1 and 2, respectively), and Qsp/Qt was 0.22 in each group. Five (28%) of 18 patients in group 1 and 19 (95%) of 20 patients in group 2 received more than 5 cm H2O of PEEP. Between groups 1 and 2 there were no statistically significant differences in days intubated (3.4 +/- 3 vs. 5.3 +/- 5, respectively), ICU days (5.3 +/- 3 vs. 6.6 +/- 5), hospitalization days (26 +/- 24 vs. 28 +/- 24), incidence of pulmonary barotrauma (0/18 vs. 1/20), ICU mortality (22% vs. 20%), or overall mortality (33% vs. 25%). The number of blood gas analyses and cardiac output measurements, and the total hospital charges were also similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Clinical validation of a new metabolic monitor suitable for use in critically ill patients.

This report documents the validity of clinical measurements of oxygen consumption (VO2) and carbon dioxide production (VCO2) made with a new metabolic gas monitor (MGM) suitable for use in critically ill patients receiving mechanical ventilatory support. Paired samples of inspired and expired gases were obtained, and exhaled minute volume was measured in 12 patients receiving supplemental oxygen, intermittent mandatory ventilation, and PEEP. Gas volume was measured with a calibrated spirometer and oxygen and CO2 fractions were measured by mass spectrometry. Measured and derived values were compared to those obtained from the MGM connected in series with the ventilator circuit. There were no statistically significant differences between values obtained from the mass spectrometer/spirometer vs. the MGM in exhaled volume (8.60 +/- 3.81 vs. 8.58 +/- 3.72 [SD] L/min), fraction of inspired oxygen (0.451 +/- 0.011 vs. 0.452 +/- 0.010), fraction of expired oxygen (0.413 +/- 0.013 vs. 0.415 +/- 0.012), VO2 (290 +/- 113 vs. 275 +/- 88 ml/min), VCO2 (245 +/- 95 vs. 247 +/- 96 ml/min), or respiratory quotient (0.85 +/- 0.14 vs. 0.88 +/- 0.08). The fraction of expired CO2 measured by the MGM was significantly greater (0.034 +/- 0.006 vs. 0.035 +/- 0.006; p less than .001) than that measured by mass spectrometer/spirometer. Twelve additional patients were studied to compare metabolic measurements made on 45% oxygen with those made at other fraction of inspired oxygen values. There was no significant difference between values measured on 45% oxygen and those measured on 30% to 50% oxygen.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Continuous venous oximetry in surgical patients.

A prospective study was performed to evaluate the efficacy of continuous venous oximetry to supplement traditional hemodynamic monitoring in 39 critically ill surgical patients. There was no statistically significant difference in SvO2 between the continuous in vivo values and in vitro values (0.694 +/- 0.095 vs. 0.698 +/- 0.108). There was no statistically significant correlation between continuously measured SvO2 and PaO2 (r = 0.09, p greater than 0.5), SaO2 (r = 0.08, p greater than 0.5), or oxygen consumption (r = 0.46, p greater than 0.5). There was a slight but statistically significant correlation between continuously measured SvO2 and cardiac output (r = 0.40, p less than 0.025) and oxygen delivery (r = 0.49, p less than 0.005). There was a highly significant correlation between continuously measured SvO2 and oxygen utilization coefficient (r = -0.96, p less than 0.001). Continuously measured SvO2 is a reliable predictor of SvO2 measured intermittently by in vitro methods. In critically ill surgical patients, SvO2 does not correlate highly with the individual determinants of oxygen transport but rather correlates with the oxygen utilization coefficient and therefore reflects the overall balance between oxygen consumption and delivery.

Cardiac Output↗
PubMed1986

Incidence of microbial colonization in open versus closed delivery systems for thermodilution injectate.

The incidence of microbial colonization of injectate was studied in open and closed delivery systems used for thermodilution measurement of cardiac output. Patients with pulmonary artery catheters were prospectively randomized to receive either open two-bottle systems or closed systems. Paired cultures of injectate solution were withdrawn through the stopcock at the time of the initial set-up and every 12 h for 48 h. Injectate from eight (35%) of 23 patients with the open system and one (5%) of 20 patients with the closed system yielded a positive culture (p less than .05). Thirteen (10%) of 129 pairs of cultures were positive from the open system, compared to one (0.9%) of 111 pairs from the closed system (p less than .01). There was no statistically significant difference in the number of cardiac output injections between the two groups, but patients having more than the mean number of injections for cardiac output measurement had a significantly (p less than .05) greater likelihood of positive injectate cultures.

Bacteriological Techniques↗
PubMed1986

Continuous monitoring of mixed venous oxygen saturation during aortofemoral bypass grafting.

Measurement of mixed venous oxygen saturation (SvO2) may be helpful in the care of critically ill patients. Serial determinations of SvO2 give an index of the relationship between oxygen delivery and tissue oxygen consumption. Continuous monitoring of SvO2 is now readily available with the Shaw Oximetrix pulmonary artery catheter (Oximetrix Inc., Mountain View, CA). This system has provided useful information in the high risk cardiac surgery patient. Continuous monitoring of mixed venous saturation may be helpful in high risk or critically ill general and peripheral vascular surgery patients both in the intensive care unit and in the operating room. The following clinical report is presented to illustrate the usefulness of continuous SvO2 monitoring in a high risk vascular surgery patient.

Aorta, Abdominal↗
PubMed1985

Patient selection for iced versus room temperature injectate for thermodilution cardiac output determinations.

In 42 patients who required hemodynamic monitoring there was no statistically significant difference between mean cardiac output determined with iced vs. room temperature injectate. There was also no statistical difference in mean cardiac output values using iced vs. room temperature injectate when data were grouped according to body temperature, mean arterial pressure, and cardiac output. These results suggest that when cardiac output is measured by the methods described, the use of iced injectate is unnecessary in many critically ill patients.

Blood Pressure↗
PubMed1984

Enzyme-linked immunosorbent assay for detection of transmissible gastroenteritis virus antibody in swine sera.

An enzyme-linked immunosorbent assay (ELISA) was developed for detection and quantification of serum antibodies to transmissible gastroenteritis virus (TGEV) in swine. Sera from pigs inoculated with cell culture-origin TGEV or gut-origin TGEV were tested for anti-TGEV antibody by ELISA and by serum virus-neutralization test (NT). The ELISA detected antibody 3 days (av) sooner than did the NT when sera from pigs inoculated with cell culture-origin TGEV were tested and 1 day sooner than did the NT when sera from pigs inoculated with gut-origin TGEV were tested. The ELISA appeared to be more sensitive than the NT, since ELISA was more responsive to low-level antibody and ELISA titers exceeded NT titers.

Animals↗
PubMed1982

Automatic vs manual injections for thermodilution cardiac output determinations.

To investigate the effects of operator variability on thermodilution cardiac output determinations, a group of physicians and nurses made a series of manual indicator injections and automatic injections using a gas powered injector in a simulated clinical situation. The data show significant variability in injection time, injectate flow rate, consistency of injection, and cardiac output values obtained during manual injections. There was little variability in these parameters during automatic injections. When other variables are properly controlled, the automatic injector may improve the precision of cardiac output measurements by controlling the consistency of injection and variables introduced by different operators performing manual injections. However, despite significant variation in parameters associated with manual injection, it is interesting to note that 8 out of 10 operators obtained cardiac output values by hand injection using room temperature injectate, which did not differ significantly from those obtained by automatic injection.

Animals↗