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Biomedical subjects

E Peterson

Publications and source records attributed to E Peterson.

At least 19 recordsLinked to original sources
PubMed1992

Effect of steroids or tissue precooling on edema and tissue thermal coagulation after CO2 laser impact.

The carbon dioxide laser is frequently used in laryngeal microsurgery. Some surgeons have empirically used preoperative steroids or precooling with ice prior to laser impact to limit the resultant tissue thermal coagulation and/or edema. An animal model was designed to quantitatively test these effects. Depillated areas of rat skin were exposed to a CO2 beam of 1 mm diameter at 15 W for 0.1 sec after either administration of Decadron (0.25 mg/kg) immediately prior to impact or precooling more than 10 degrees C below basal body temperature. Measurement of edema was quantitated as extravasation of Evans's blue dye that had been injected intravenously. Tissue thermal coagulation was measured on hematoxylin and eosin stained histologic sections. In comparison to controls, statistically significant reduction in edema was seen only at the 24 hour time period after laser exposure for the steroid group (P less than .002) but not for the precooling group. Tissue thermal coagulation was significantly smaller for both the steroid and the ice group (P less than .006 and P less than .001, respectively) when compared to controls.

Animals↗
PubMed1992

Nonmembrane associated dolichol in rat liver.

The distribution of dolichol in rat liver was studied. Upon high-speed centrifugation, 9% of the total tissue dolichol was recovered in the supernatant. Dolichol was enclosed in vesicles and in lipidic particles which were isolated by gel filtration and density gradient centrifugation. The particles had a diameter of 20 nm and contained dolichol, ubiquinone, cholesterol, phospholipid and some protein. Similar particles were recovered upon incubation of isolated hepatocytes with liposomes containing dolichol. From the lysosomal lumen, lipid particles containing dolichol, ubiquinone, cholesterol and phospholipid, but no protein, were isolated. The diameter of the particles was 20-40 nm with a molecular weight of 130 kDa. Puromycin treatment inhibited protein synthesis, but did not affect dolichol transfer from the endoplasmic reticulum to lysosomes, suggesting that the transfer is not mediated by newly synthesized apoprotein. The results indicate that a sizeable portion of the total cellular dolichol is present in cytoplasm and in lysosomal lumen. Furthermore, dolichol probably participates in the translocation process.

Animals↗
PubMed1991

Traumatic events and posttraumatic stress disorder in an urban population of young adults.

To ascertain the prevalence of posttraumatic stress disorder (PTSD) and risk factors associated with it, we studied a random sample of 1007 young adults from a large health maintenance organization in the Detroit, Mich, area. The lifetime prevalence of exposure to traumatic events was 39.1%. The rate of PTSD in those who were exposed was 23.6%, yielding a lifetime prevalence in the sample of 9.2%. Persons with PTSD were at increased risk for other psychiatric disorders; PTSD had stronger associations with anxiety and affective disorders than with substance abuse or dependence. Risk factors for exposure to traumatic events included low education, male sex, early conduct problems, extraversion, and family history of psychiatric disorder or substance problems. Risk factors for PTSD following exposure included early separation from parents, neuroticism, preexisting anxiety or depression, and family history of anxiety. Life-style differences associated with differential exposure to situations that have a high risk for traumatic events and personal predispositions to the PTSD effects of traumatic events might be responsible for a substantial part of PTSD in this population.

Adult↗
PubMed1991

Quality screening and management using claims data in a managed care setting.

Quality screening and management (QSM), developed by United HealthCare Corporation for its own health plans but applicable to other settings, analyzes health care provided to an enrolled population using claims and administrative data supplemented, when necessary, with medical record review. For selected topics/conditions, QSM compares the care received by patients to that recommended by established practice guidelines and also reports and describes quality through incidence rates, condition-specific process and outcome measures, occurrence of adverse events, and use of preventive services. Results of the analyses are linked to appropriate quality management actions and are used to identify strategies for improvement. Data permit health plans to make performance comparisons on individual indicators and longitudinal comparisons on the effectiveness of quality improvement initiatives.

Humans↗
PubMed1991

Use of emergency services by unaccompanied minors.

STUDY OBJECTIVE: The objective of the study was to describe the use of emergency services by minors who are unaccompanied by their parents or guardians and how they are managed in emergency departments. DESIGN: Self-administered survey. TYPE OF PARTICIPANTS: The ED directors of 71 emergency medicine training programs, 82 Michigan community EDs, and 56 pediatric EDs. MEASUREMENTS AND MAIN RESULTS: One hundred eighteen (58%) surveys were returned. A median of five unaccompanied minors (range 0.2 to 150) were seen weekly by responding EDs. Pediatric EDs saw the most unaccompanied minors weekly (ten) compared with training programs (five) and community EDs (three) (P less than .01). Emergency medicine training programs had the greatest percentage (3.0%) of minors who were unaccompanied compared with pediatric EDs (2.2%) and community EDs (2.6%) (P less than .05). For all conditions surveyed, only 3.8% of patients would be refused medical care without parental consent. However, 36.8% of patients would have medical care delayed even for conditions that might be painful or harmful if left untreated for some time. Most EDs (85.5%) screen patients and treat those who are acutely ill, but some (11.1%) treat all regardless of severity. CONCLUSION: Protocols should be developed for unaccompanied minors to ensure that delays in obtaining consent do not jeopardize the child and that the rights of minors for confidentiality and consent are recognized.

Adolescent↗
PubMed1991

Comparison of rectal, axillary, and tympanic membrane temperatures in infants and young children.

STUDY OBJECTIVE: To evaluate the reliability of a tympanic membrane thermometer in detecting fever in young children presenting to the emergency department. SETTING: Pediatric emergency department in an urban teaching hospital, DESIGN/MEASUREMENT/PARTICIPANTS: Temperature measurements were obtained sequentially at three body sites in children less than 3 years old presenting to the pediatric ED. Axillary and rectal temperatures were obtained with an electronic thermistor probe (Diatek 500), and tympanic membrane temperatures were obtained with a noncontact, infrared sensing device (First TEMP). Patients were stratified by age, ear canal patency, presence of otitis media, and rectal temperature. RESULTS: Of 224 patients enrolled, 87 (39%) were febrile. Overall correlation of axillary and tympanic membrane measurements to rectal for all strata was .75 (P = .001) and .81 (P = .001), respectively. Sensitivity in detecting fever for axillary and tympanic membrane sites was .48 and .55, respectively. Otitis media and ear patency did not influence correlation of tympanic membrane measurements. Low tympanic membrane temperature sensitivity may be a result of probe configuration. CONCLUSION: Tympanic membrane and axillary temperatures should be viewed with caution in children less than 3 years old as neither can detect fever reliably.

Axilla↗
PubMed1991

Embolic stroke in aged rats.

BACKGROUND AND PURPOSE: Although stroke is a disorder associated with aging, experimental studies of stroke are conducted in young adult (2-4-month-old) animals (rat life span, 27-29 months). To determine whether histopathologic changes caused by cerebral infarction would be altered in aged animals, we produced embolic cerebral infarction in 17 aged (23-24-month-old) and 16 young (2-4-month-old) rats. METHODS: The right common carotid artery was irradiated with a laser (632 nm, 200 mW/cm2, 15-20 minutes) after the intravenous injection of the photosensitizing dye Photofrin II (12.5 mg/kg). This produces a nonocclusive platelet thrombus that spontaneously embolizes to the brain. Animals were killed 4 days later. RESULTS: Analysis was done on 142 infarcts, 68 in aged rats and 74 in young rats. Hypercellularity, with infiltration of macrophages, was more common within small infarcts (less than 1 mm) in young than in aged rats (p = 0.002), and hypertrophy of astroglial fibers surrounding the infarcts was more prominent in young rats. Larger infarcts (greater than or equal to 1 mm) were often hypocellular, with a trend toward more macrophages in the periphery of the infarcts in young than in old animals (p = 0.170). CONCLUSIONS: The infiltration of macrophages into cerebral infarcts and the hypertrophy of astroglial fibrils surrounding these infarcts are reduced in the aged rat. These age-related differences emphasize the importance of using appropriately aged animals in experimental models of stroke.

Aging↗
PubMed1991

How it all happened.

Explore the source record for details and available documents.

History, 20th Century↗
PubMed1990

Measurement of vertebral area on spine x-rays in osteoporosis: reliability of digitizing techniques.

Much of the clinical research in osteoporosis is directed toward documenting a reduction in vertebral fracture rate, but there is considerable disagreement about defining and quantifying vertebral fractures. We have evaluated the technique of digitizing landmarks identified on lateral radiographs of thoracic and lumbar vertebrae and computing vertebral body area. Reduction in area indicates that fractures occurred. Radiographs from 10 patients with osteoporosis and vertebral fractures were obtained from each of two centers. Henry Ford Hospital (HFH) and Mayo Clinic (MC), and vertebral area for each individual in the complete set of 20 radiographs was calculated at each center. Measurements at the two centers differed by a multiplicative constant related to the method of recording landmarks on the radiographs that was estimated using 300 x-rays from HFH. After adjusting the MC areas for this multiplicative relationship, the average ratio of the HFH areas to the transformed MC areas of individual vertebrae (T4-L5) ranged from 0.98 to 1.06. The correlation between HFH and transformed MC areas for individual vertebrae averaged 0.85, with slopes between 0.87 and 1.00, intercept average -0.57. Within-patient rank correlation averaged 0.97. We conclude that radiographic digitization is a reliable and reproducible method of determining vertebral body dimensions that is suitable for evaluating radiographs obtained at different clinical sites and for comparison with normal data. This technique should prove useful for documenting the presence of a vertebral fracture that may not be readily apparent on visual inspection of radiographs and for monitoring serial changes in vertebral body dimensions in long-term epidemiologic and therapeutic studies.

Aged↗
PubMed1990

Free amino acid analysis of guinea pig perilymph: a possible clinical assay for the PLF enigma?

Controversy prevails regarding the accuracy of the clinical diagnosis of perilymphatic fistula (PLF). The diagnosis of PLF has been based on the subjective evaluation of vestibular function tests and the intraoperative macroscopic visualization of "clear fluid" from the oval/round windows at the time of exploratory tympanotomy. However, the subjective visual characterization of PLF varies among observing surgeons. Furthermore, perilymph can be "contaminated" with serum, blood, cerebrospinal fluid (CSF), and local anesthesia. This article presents a scientific biochemical microassay for the free amino acid profile of perilymph. Microaliquots of uncontaminated perilymph were sampled from the bilateral round windows (scala tympani) of 20 guinea pigs and analyzed for 19 free amino acid concentrations (FAAC) by high-performance liquid chromatography (HPLC). These samples were compared with the FAAC of guinea pig serum samples. Perfect predictor value ranges were nonoverlapping for 12 of 19 free amino acids in perilymph vs. plasma. Amino acid microassay of middle ear fluid for verification of "true" perilymph vs. nonperilymph fluids by the identification of nonoverlapping FAA markers may allow scientific verification of the existence of PLF in "suspected" patients.

Amino Acids↗
PubMed1990

Relationship between values of bioelectrical impedance and creatinine clearance.

This investigation was conducted to determine if measurements of bioelectrical impedance in conjunction with serum creatinine concentrations are useful in predicting creatinine clearance. Twenty-eight healthy volunteers between 23 and 50 years of age followed an individualized protein diet to provide 1.2 g protein/kg/day for 3 consecutive days. At the beginning of day 3, a 24-hour urine collection was initiated. At the midpoint of urine collection, bioelectrical impedance measurements of resistance and reactance were taken, together with a single blood sample for assessment of serum creatinine concentration. Multiple linear regression techniques were used to identify significant values for predicting creatinine clearance. Resistance and serum creatinine concentration were identified as significant predictors. The measured creatinine clearance was compared to that predicted by the impedance-derived model that we developed, as well as other established estimation methods. Mean absolute prediction errors in creatinine clearance using this model were significantly lower than those obtained using four empiric methods. Bioelectrical impedance may provide a noninvasive, quick, and accurate method for predicting creatinine clearance from serum creatinine concentration values.

Adult↗
PubMed1990

The surgical management of atypical mycobacterial soft-tissue infections.

Group IV atypical mycobacterial infections, especially Mycobacterium fortuitum and M. chelonei, are being reported with increased frequency. We report our experience with five cases of soft-tissue infection with these acid-fast bacilli. Often these infections are chronic, with formation of abscesses and multiple fistulas. Optimal surgical treatment often requires wide excision of all diseased tissue followed by delayed closure. Presentation, optimal surgical management, and antibiotic therapy are discussed.

Abscess↗
PubMed1989

Identification of women at risk for developing postmenopausal osteoporosis with vertebral fractures: role of history and single photon absorptiometry.

Putative risk factors for the development of postmenopausal osteoporosis (PMO) with vertebral fractures were examined in a retrospective study of 663 postmenopausal white females aged 45-75 years (266 women with non-traumatic vertebral compression fractures (VF+), 134 non-fractured women from a general medicine clinic (controls) and 263 non-fractured women who were evaluated when they presented specifically for osteoporosis screening (VF-]. The VF+ women differed from control women in several respects. The VF+ group reported a higher prevalence of a positive family history of osteoporosis, and a higher prevalence of a history of medical or surgical conditions known to be independently associated with metabolic bone disease, had fewer children, were smaller (weight, height) and were slightly older. The two groups, VF+ and controls, did not differ with respect to cigarette smoking, alcohol consumption, exercise habits, menstrual or menopausal history, dietary intake of milk and cheese or in amount taking calcium supplements during pregnancy. The VF+ group also differed in certain respects from the VF- group. The VF+ group were smaller (weight, height) and were older. The VF+ group had lower cortical bone mass (measured by single photon absorptiometry of the non-dominant forearm) than either the control or VF- groups. The latter two groups did not differ from each other with respect to this measurement. These markers demonstrated limited sensitivity and specificity as estimated from a confirmatory data set, particularly for the historical and anthropometric variables. We conclude that an assessment of the risk of developing PMO with vertebral fractures cannot be based on the putative risk factors as measured in our study, but must be based on measurement of bone mass.

Absorptiometry, Photon↗
PubMed1989

Fatty acid oxidation in hepatic peroxisomes and mitochondria after treatment of rats with di(2-ethylhexyl)phthalate.

Rats were fed a diet containing di(2-ethylhexyl)-phthalate, which increases the number of peroxisomes and mitochondria in the liver. This proliferation does not change the ratio of phospholipid to protein in mitochondria or microsomes, but causes certain changes in the fatty acid composition of the phospholipids. The highest rates of peroxisomal and mitochondrial beta-oxidation are obtained with 12:0 and 16:0 fatty acids as substrates, respectively. A 3-4 fold increase in the rate of beta-oxidation by both organelles is caused by DEHP treatment, but there are no qualitative changes in the relative rates of oxidation of individual fatty acids. Short- and medium-chain carnitine acyltransferases in peroxisomes, microsomes and mitochondria, as well as the mitochondrial long-chain carnitine acyltransferase are induced to various extents. These results indicate that the increased beta-oxidation of fatty acids caused by phthalate treatment involves the same peroxisomal and mitochondrial pathways which operate under normal conditions.

Animals↗
PubMed1989

Comparison of monoclonal antibodies for rapid detection of cytomegalovirus in spin-amplified plate cultures.

Cytomegalovirus (CMV) was detected in 56 of 275 specimens (20%); 50 of 56 (89%) were detected by conventional culture, and 37 (66%) were detected by rapid assay at 72 h with a commercial monoclonal antibody and a pooled monoclonal antibody. Although the two antibodies were equally sensitive at 72 h, the pooled antibody gave a brighter, more easily detected signal. Other viruses were isolated from 9 specimens (3.3%) by conventional culture. Use of rapid assays alone fails to detect slow-growing CMV and non-CMV viral pathogens.

Antibodies, Monoclonal↗
PubMed1989

Relationship of bioelectrical impedance to pharmacokinetic parameters of theophylline in healthy males.

Bioelectrical impedance is a reliable, safe, non-invasive and valid method of determining body composition, using measures of resistance and reactance by passing a low voltage alternating current through the body. This study investigates relationships between the pharmacokinetics of theophylline and parameters of bioelectrical impedance in 15 non-smoking, healthy, adult male volunteers. After an overnight fast, subjects received 5 mg/kg of aminophylline intravenously over 30 minutes. Blood samples were obtained serially over a period of 12 hours. Bioelectrical impedance measurements were made in triplicate, using a 4-electrode plethysmograph. Sera were assayed in duplicate by enzyme-mediated immunoassay (coefficient of variation less than 5%), and data were fitted to a non-compartmental regression program. An all-subsets multiple-regression technique was employed to arrive at predictive equations for theophylline clearance (CL) and volume of distribution at steady-state (Vss) using age, height, weight and mean bioelectrical impedance parameters. Equations for Vss and CL revealed p-values of less than 0.001 and coefficients of variation of 8.5 and 13.33% respectively. Although the equations display some degree of colinearity they account for 95 and 86.5% of the variability in Vss and CL respectively, and represent an innovative approach to the estimation of pharmacokinetic parameters.

Adult↗
PubMed1988

Frequency and significance of cardiac arrhythmias in chronic obstructive lung disease.

Ambulatory electrocardiograms obtained in 69 patients enrolled in the nocturnal oxygen therapy trial group were examined for frequency and significance of arrhythmias in patients with stable chronic obstructive lung disease. Ventricular premature beats occurred in 83 percent, ventricular bigeminy in 68 percent, paired ventricular premature beats in 61 percent, and nonsustained ventricular tachycardia in 22 percent of the patients. Supraventricular tachycardia occurred in 69 percent. Repetitive ventricular arrhythmia occurred in 64 percent of the patients, and was significantly more frequent in men and in patients with edema or elevated PCO2. Ventricular premature beats greater or equal to 25 per hour occurred in 35 percent of the patients. Univariate and multivariate Cox proportional hazards analysis showed that a history of coronary heart disease, increased sinus heart rate and decreased maximum work load (measured by maximal treadmill exercise test)--but not arrhythmias--were predictors of death.

Aged↗