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Biomedical subjects

J R Swanson

Publications and source records attributed to J R Swanson.

18 recordsLinked to original sources
PubMed1992

Serial ECGs are less accurate than serial CK-MB results for emergency department diagnosis of myocardial infarction.

HYPOTHESIS: Serial creatine kinase-MB (CK-MB) levels provide more accurate predictive information regarding myocardial infarction than serial ECGs in emergency department patients with chest discomfort and no ST-segment elevation on the initial ECG. DESIGN: Prospective, observational study. SETTING: University hospital and university-affiliated Veterans Affairs Medical Center EDs. PARTICIPANTS: Two hundred sixty-one patients 30 years or older with chest discomfort warranting an ECG and consenting to observation. Exclusions included hemodynamic or rhythm instability and ST-segment elevation of 0.1 mV or more in two or more electrically contiguous leads at presentation. MEASUREMENTS: ECGs were obtained at presentation and three to four hours after presentation. Significant serial ECG changes sought on comparison of initial and three- to four-hour ECGs were 0.05 mV or more ST elevation or depression, Q-wave development, or T-wave inversion changes in two or more electrically contiguous leads. CK-MB levels were obtained at presentation and hourly for three hours (positive level, 8 or more ng/mL). Myocardial infarction was determined by record review and was based on independent CK-MB measurements. RESULTS: Twenty-eight (11%) patients were diagnosed with a myocardial infarction. Thirty-eight (15%) patients had a serial ECG change. Eleven of the myocardial infarction patients (39%) had a serial ECG change compared with 27 (12%) of the non-myocardial infarction patients (P < .001). Sensitivities and specificities of a serial ECG change versus serial CK-MBs for myocardial infarction were 39% versus 68% (sensitivity) and 88% versus 95% (specificity), respectively. Serial CK-MBs were more accurate than a serial ECG change for predicting myocardial infarction (P < .03). CONCLUSION: Serial changes in ECGs during a three- to four-hour interval were associated with the diagnosis of myocardial infarction but were infrequent and less accurate than serial CK-MB levels obtained for the same interval.

Adult↗
PubMed1991

The immunogenicity and safety of intradermal hepatitis B vaccine.

BACKGROUND: One of the chief barriers to a greater use of hepatitis B vaccine is the high cost of the vaccine itself. A number of small research trials have shown that an adequate immune response can be induced at a much lower cost by administering one tenth of the vaccine using an intradermal technique. The purpose of this study was to ascertain whether these results could be replicated in a larger clinical trial. METHODS: Vaccine recipients included health care providers, police officers, and firefighters. Recipients were given 0.1 mL of plasma-derived hepatitis B vaccine intradermally on days 1, 30, and 180. Antibody response was measured on day 210, with seroconversion defined as a sample-to-negative (S/N) ratio of greater than or equal to 10. Any local and systemic side effects were documented. RESULTS: Six hundred sixteen individuals completed the vaccination series, and seroconversion occurred in 534 (86.7%). The rate of seroconversion in those younger than 40 years was 91.2% and in those 40 years and older was 75.1%. The mean S/N ratio was 154.9 (range 0 to 620) and decreased with increasing age (r = -.25, P = .0001). Side effects were largely limited to local reactions. CONCLUSIONS: The results support the use of the intradermal technique as a cost-effective alternative to the intramuscular route in individuals younger than 40 years. The intradermal technique may be used in older individuals if titers are obtained to assure seroconversion. Because of the restricted availability of the plasma-derived vaccine used in this study, similar trials with recombinant vaccine should be undertaken.

Adolescent↗
PubMed1989

Cyclosporine determinations in heart and kidney transplant patients: comparison of high-performance liquid chromatography, polyclonal, and monoclonal methods.

We have analyzed and compared the cyclosporine concentrations in whole blood specimens from heart and kidney transplant patients, using three different methods: high-performance liquid chromatography (HPLC), polyclonal radioimmunoassay, and monoclonal radioimmunoassay. HPLC results for heart transplant patients correlated well with the monoclonal (specific antibody) results but did not correlate with the polyclonal (nonspecific antibody) results. All three methods correlated well for renal transplant patients; however, polyclonal results were consistently higher than either monoclonal or HPLC results. We conclude that the results from the monoclonal (specific antibody) RIA are equivalent to HPLC results for both kidney and heart transplant patients.

Chromatography, High Pressure Liquid↗
PubMed1989

Massive levothyroxine ingestion. Conservative management.

The clinical course of a 29-month-old girl who was referred for evaluation after ingesting ninety 0.2-mg tablets of levothyroxine is reported. Despite an initial thyroxine (T4) level of 282 micrograms/dl and a triiodothyronine (T3) level of 1,837 ng/dl at 48 hours postingestion, her symptoms were mild and included irritability, vomiting, tremor, and tachycardia. Treatment was limited to activated charcoal and propranolol. Thyroid hormone levels fell to normal by 13 days postingestion. The child's clinical course was benign. Even after massive acute ingestions of levothyroxine, children's symptoms are usually mild and may be controlled with propranolol. This conservative approach should be considered before expensive and potentially dangerous therapies are undertaken.

Charcoal↗
PubMed1989

Multicenter evaluation of TDx test for assessing fetal lung maturity.

"TDx Fetal Lung Maturity," an automated assay that measures the relative concentrations of surfactant and albumin in amniotic fluid, was compared with the lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol determination at five clinical sites. A total of 695 amniotic fluid samples were analyzed, of which 312 were followed by delivery of the infant within three days of sample collection. Of these 312, 24 developed respiratory distress syndrome and seven developed transient tachypnea. With the cutoff for maturity set at a surfactant/albumin value of 50 mg/g, the assay showed a sensitivity of 0.96 and a specificity of 0.88 for all samples, compared with a sensitivity of 0.96 and a specificity of 0.83 for the L/S ratio. The combination of rapid assay (30 min), accurate results, and uniformity among testing centers makes the TDx assay a very promising method.

Albumins↗
PubMed1987

Effect of albumin and lamellar bodies on fluorescence polarization of amniotic fluid.

Using a probe and procedure developed for the Abbott TDx analyzer, we investigated the influence of albumin on fluorescence polarization of amniotic fluid. Polarization readings increased when albumin was added to either "mature" or "immature" amniotic fluids. Albumin added to a fraction rich in lamellar bodies (10,000 X g pellet) greatly increased polarization readings, but albumin added to the lamellar-body-free fraction resulted in only small increases. Adding increasing amounts of the lamellar-body-rich fraction from mature and immature pools to a constant amount of albumin decreased the polarization readings. We saw no correlation between amniotic fluid polarization and albumin concentration but found a significant correlation between polarization values and either total extractable phospholipids (r = 0.725, P less than 0.001) or the ratio albumin/total extractable phospholipids (r = 0.784, P less than 0.001). The concentration of albumin in amniotic fluid was variable and correlated poorly with gestational age.

Albumins↗
PubMed1987

Modified lamellar body phospholipid assay compared with L/S ratio and phosphatidylglycerol assay for assessment of fetal pulmonary status.

We used a modified lamellar body phospholipid (LB-PL) assay to evaluate the effect of sample processing and to evaluate the clinical efficacy of LB-PL determinations. Within-run and between-run CVs for the modified LB-PL assay respectively ranged from 2.9 to 6.7% and from 3.4 to 14.3%. Freezing and storage at -20 degrees C did not affect results for LB-PL (n = 12). Statistically significant amounts of lamellar bodies were lost on centrifugation, ranging from 20% at 150 X g to 54% at 1000 X g for 5 min. The LB-PL content, lecithin/sphingomyelin ratio, and phosphatidylglycerol content of 194 samples of amniotic fluid obtained within three days of delivery were compared for the assessment of fetal pulmonary maturity. Twenty-three neonates developed respiratory problems at or shortly after birth. With uncontaminated samples (n = 160), the LB-PL assay exhibited better specificity than the lecithin/sphingomyelin ratio (p less than 0.01, Chi square) or the phosphatidylglycerol assay (p less than 0.001, Chi square) for samples obtained after 36 weeks of gestation. Assay sensitivities did not differ significantly. Differences among assay predictive values were not significant.

Amniotic Fluid↗
PubMed1986

Mid-molecule parathyroid hormone assay comparison.

Parathyroid hormone (PTH) assays are becoming available to clinical chemistry laboratories for in-house use. We evaluated the clinical utility of two mid-molecule PTH assays in comparison to a sensitive but technically demanding component assay. A normal reference population, and an abnormal population including cases of primary and secondary hyperparathyroidism, hypoparathyroidism, and humoral hypercalcemia of malignancy were tested. PTH determinations with each assay system and total serum calcium determinations were done on all specimens. The Endocrine Metabolic Center (EMC) kit assay and the Immuno Nuclear Corp. (INC) kit assay demonstrated adequate standard curve reproducibility and precision for clinical use. With the aid of calcium determinations each assay performed well in the separation of abnormal patient groups, and in the separation of abnormal from normal PTH-calcium homeostasis. PTH values for the reference population differed among the three assays. The component assay and the EMC assay had a negative correlation with serum calcium, but the INC assay had a positive correlation with serum calcium.

Calcium↗
PubMed1977

Ultraviolet spectrometry of serum triglycerides by a totally enzymic method adapted to a centrifugal analyzer.

We described a micromethod for determining serum triglycerides (triacylglycerols) with the centrifugal analyzer. This technique is based on the procedure of Bublitz and Kennedy [J. Biol. Chem. 211, 951 (1954)]. The enzymic hydrolysis requires 10 min at 30 degrees C. Twenty-six serum triglyceride assays can be done in about 30 min. Concentration and absorbance are linearly related up to 5.0 mmol/liter, but higher concentrations can be assayed by changing conditions slightly. Day-to-day reproducibility for the method was satisfactory (CV, 2.7 to 8.4%). Comparison of this method and two other methods for triglycerides, the automated Hantzsch condensation method and a commercial enzymic method (Calbiochem), gave correlation coefficients of 0.976 and 0.990, respectively. Results are unaffected by the presence of endogenous serum ADP, pyruvic acid, phosphatases, or ATPase.

Centrifugation↗
PubMed1976

Serum creatine phosphokinase in normal newborns.

Serum creatine phosphokinase (CPK) activity in 70 normal newborns was found to be significantly higher than the normal values found in adults or older children, and in some cases reached a level up to 10 times normal. It declined to near normal activity during the first 4 days and to normal level of activity by age 6-10 weeks. No clear correlation between birth trauma and increase in serum CPK activity was shown. CPK activity in cord blood was lower than in venous and capillary blood. Because of the increased CPK activity found in normal newborns, screening for Duchenne-type muscular dystrophy should be postponed for a few weeks after delivery.

Age Factors↗
PubMed1975

A prospective evaluation of the lecithin/sphingomyelin ratio and the rapid surfactant test in relation to fetal pulmonary maturity.

Fetal lung maturity was correlated to the results of amniatic fluid analysis in 578 samples obtained over a 2 1/2 year interval. Lecithin/sphingomyelin (L/S) ratios obtained by planimetric and densitometric methods were compared to the rapid surfactant test (RST). Both the planimetric L/S ratio (P L/S) and the densitometric L/S ratio (D L/S) correlated positively in a highly significant fashion with the RST. Both RST and D L/S were reliable in predicting fetal lung maturity (99 to 100 per cent, respectively). The RST was the most reliable test for fetal lung immaturity (69 per cent). Therefore, this series indicates that the RST could be used as a primary method with the D L/S being useful as an additional indicator of fetal maturity when the RST was intermediate, or the sample contaminated with blood and/or meconium.

Amniotic Fluid↗
PubMed1975

Serum biochemical and electrophoretic values from four deer species and from pronghorn antelope.

Serums from 4 species of deer and 1 species of antelope were analyzed for various components in order to define an animal disease model for sickle cell disease in people. Animal species included black-tailed deer (Odocoileus hemionus columbianus), mule deer (Odocoileus hemionus), sika deer (Cervus nippon nippon), fallow deer (Dama dama), and pronghorn antelope (Antilocapra americana). The mean serum values for total bilirubin, total protein, albumin, creatinine, urea nitrogen, and electrolytes were similar in all species and were in the normal range for human beings. Cholesterol and uric acid values for all animals were lower than those for people. Alkaline phosphatase values in the 4 cervid species were higher than in the pronghorn antelope. Values for glutamic oxalacetic transaminase were lower in the cervids than in the pronghorn antelope. Lactic dehydrogenase values were similar in the 5 species. High activities for glutamic oxalacetic transaminase and lactic dehydrogenase in the 5 species probably related to muscle mass and great muscular activity.

Alkaline Phosphatase↗