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Biomedical subjects

L E Johnson

Publications and source records attributed to L E Johnson.

At least 19 recordsLinked to original sources
PubMed1991

The incidence of attempted CPR in nursing homes.

We studied the frequency with which cardiopulmonary resuscitation (CPR) is attempted on residents of American nursing homes. Each author (all members of the Clinical Practice Committee of the American Geriatrics Society) completed a questionnaire in 1989 about policy and practice regarding CPR during 1988 in each of three to seven nursing homes, by questioning the medical or nursing director or the administrator. Because of the vagaries of nursing home record-keeping, data from some homes were allowed when they were "accurate to within 10%." Data from 58 nursing homes, totalling 10,836 bed-years were available. In 33 of these homes, accounting for 5,425 bed-years, CPR was never attempted. CPR was more likely to be foregone in nursing homes with religious affiliation than in nursing homes without (13 of 17 vs 18 of 38; chi 2 = 4.0; P less than 0.05). Religious affiliation was unknown for three nursing homes. Academic affiliation (10 of 16 vs 20 of 37 in non-affiliated nursing homes) and non-profit status (14 of 19 vs 16 of 23 in for-profit nursing homes) did not significantly affect the likelihood that CPR would never be used. In 31 of 54 nursing homes with explicit do not resuscitate (DNR) policies, CPR was never performed, compared to 2 of 4 homes without such policies. For nursing homes with complete data, there were 1,196 deaths in 32 facilities where CPR was never attempted compared to 1,294 deaths for 24 nursing homes with CPR. For 22 nursing homes without CPR, there were 2,172 emergency room transfers compared to 1,363 emergency room transfers in 18 nursing homes where CPR was attempted.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Hospital admission for xanthine toxicity.

A follow-up study of 35,909 outpatients who filled more than 220,000 prescriptions for theophylline over 9 years revealed 30 hospitalizations for xanthine toxicity. The overall estimated incidence rate of 7.8/10,000 person-years at risk indicates that in this population, hospitalization for xanthine toxicity is a relatively rare event.

Adolescent↗
PubMed1988

Evaluation of a combination of xylazine, ketamine, and halothane for anesthesia in llamas.

Anesthesia induced by use of a combination of xylazine, ketamine, and halothane, under conditions of spontaneous and mechanically controlled ventilation, was evaluated in 5 llamas positioned in dorsal recumbency. Using chronically implanted catheters, systemic arterial blood pressure, pulmonary arterial pressure, right atrial pressure, heart rate and rhythm, cardiac output, blood pH and gas tensions, body temperature, and respiratory rate were measured before anesthesia induction (baseline), throughout the anesthetic period, and for 1 hour into the recovery period. During anesthesia, llamas undergoing spontaneous ventilation developed hypercapnia and respiratory acidosis. Cardiovascular function was decreased during both types of ventilation. The combination of xylazine, ketamine, and halothane in various doses and 2 ventilation procedures (spontaneous and controlled) provided a reliable method for general anesthesia in llamas, but marked cardiovascular depression developed during anesthesia maintenance with halothane. Spontaneous ventilation resulted in potentially clinically important respiratory acidosis.

Anesthesia, General↗
PubMed1987

Early and late global and regional left ventricular function after experimental transmural myocardial infarction: relationships of regional wall motion, wall thickening, and global performance.

Experimental myocardial infarction of the posterolateral wall of the left ventricle was produced in dogs by injecting 80 micron microspheres into the left circumflex coronary artery to determine changes in regional myocardial function after infarction, to examine how the changes in regional myocardial function relate to the changes in global left ventricular function, and to examine the relationship between regional wall motion and wall thickening after myocardial infarction. Serial measurements of global ventricular and regional myocardial function were made in six dogs before and during 20 days after infarction, with the use of M-mode echocardiography and chronic Swan-Ganz catheter implantation. One hour after infarction, stroke volume index had decreased 49% from baseline, percent fractional shortening had decreased 52%, lateral wall motion had decreased 80%, and lateral wall thickening had decreased 100%. By 6 days after infarction, stroke volume index had increased 41% from its low point, percent fractional shortening had increased 34%, and lateral wall motion had increased 100% toward but not to baseline. Lateral wall thickening did not return following infarction. Peak and end-systolic circumferential wall stresses and systemic arterial blood pressure remained stable. End-systolic diameter increased acutely (36%) after infarction and did not change during the 20-day time period, while end-diastolic diameter gradually increased, resulting in the increase in percent fractional shortening. In conclusion, after posterolateral wall infarction, wall motion can return without an improvement in regional myocardial function, presumably because the infarcted region stiffens, allowing it to be pulled inward.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Neurohumoral and cardiopulmonary response to sustained submaximal exercise in the dog.

Neurohumoral, cardiovascular, and respiratory parameters were evaluated during sustained submaximal exercise (3.2 km/h, 15 degrees elevation) in normal adult mongrel dogs. At the level of activity achieved (fivefold elevation of total body O2 consumption and threefold elevation of cardiac output), significant (P less than 0.05) increases in plasma norepinephrine and epinephrine concentration (from 150 +/- 23 to 341 +/- 35 and from 127 +/- 27 to 222 +/- 31 pg/ml, respectively) were present, as well as smaller but significant increases in plasma renin activity and plasma aldosterone concentration (from 2.2 +/- 0.3 to 3.1 +/- 0.6 ng X ml-1 X h-1 and from 98 +/- 8 to 130 +/- 6 pg/ml, respectively). Plasma arginine vasopressin increased variably and insignificantly. The cardiovascular response (heart rate, systemic arterial and pulmonary arterial pressures, left ventricular filling pressure, and calculated total peripheral and pulmonary arteriolar resistance) closely paralleled that of human subjects. Increased hemoglobin concentration was induced by exercise in the dogs. The ventilatory response of the animals was characterized by respiratory alkalosis. These data suggest similarities between canine and human subjects in norepinephrine, plasma renin activity, and plasma aldosterone responses to submaximal exercise. Apparent species differences during submaximal exertion include greater alterations of plasma epinephrine concentration and a respiratory alkalosis in dogs.

Aldosterone↗
PubMed1986

The value of skin testing for penicillin allergy diagnosis.

Skin testing is reliable and useful to rule out penicillin allergy in most patients who have a history of previous reactions. When we tested 291 inpatients in the University of Washington hospitals for the presence or absence of penicillin allergy, of 97 with a history of penicillin allergy, 12 (12.4%) had positive skin tests. Of 194 patients with no or an unknown history, only 4 (2%) had positive skin tests. Two of the 16 who had positive skin tests (12.5%) reacted only to minor determinant mixtures. Of the skin test-negative patients, 261 were treated with one of the penicillins and only two had any reactions.

Drug Hypersensitivity↗
PubMed1985

Acute hemodynamic effects of hydralazine in dogs with chronic mitral regurgitation.

The hemodynamic response to hydralazine administration was evaluated in 6 conscious small dogs with chronic mitral regurgitation. All dogs underwent invasive and noninvasive hemodynamic monitoring before and after hydralazine administration. Cardiac output and pulmonary capillary wedge pressure were measured with a Swan-Ganz thermodilution catheter. Systemic arterial blood pressure (AP) was measured directly by inserting a needle into the femoral artery. Standard M-mode echocardiograms and thoracic radiographs were obtained. Other hemodynamic variables were calculated. Base-line hemodynamic variables were altered severely in all dogs. Hydralazine decreased mean arterial blood pressure from 104 +/- 18 (mean +/- SD) to 78 +/- 12 mm of Hg (P less than 0.005), total systemic resistance index from 2,946 +/- 625 to 1,261 +/- 420 dynes-s-cm-5m2 (P less than 0.005), and pulmonary capillary wedge pressure from 40 +/- 5 to 26 +/- 3 mm of Hg, (P less than 0.005). Cardiac index increased from 2.92 +/- 0.72 to 5.36 +/- 1.67 L/min/m2 of body surface area (P less than 0.005). Mixed venous oxygen tension (PvO2) increased from 28.4 +/- 4.3 to 41.2 +/- 5.2 mm of Hg (P less than 0.001). Pulmonary edema resolved, as determined on thoracic radiographs. Mixed venous oxygen tension correlated well with the cardiac index (r = 0.92; P less than 0.001). It was concluded that hydralazine administration caused a small decrease in end diastolic diameter (4.8 +/- 0.9 to 4.5 +/- 0.8 cm, P less than 0.05) and end systolic diameter (2.6 +/- 0.8 to 2.3 +/- 0.7 cm, P less than 0.05). Fractional shortening and heart rate did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Anorexia nervosa and bulimia in female adolescents with insulin dependent diabetes mellitus: a systematic study.

An unselected sample of 46 female adolescents with insulin-dependent diabetes mellitus (IDDM) for more than one year were assessed systematically for the presence of anorexia nervosa and bulimia. These disorders and their partial syndromes were found in 19.5% of this population. Anorexia nervosa and bulimia diagnosed on the basis of DSM-III criteria were each found in 6.5% of the population representing approximately a 6-fold and 2-fold increase respectively in the expected prevalence for similar nondiabetic individuals. Bulimic symptoms were associated with poor metabolic control as reflected in blood levels of glycosylated hemoglobin (HbAl). These findings have important implications both for the pathogenesis of anorexia nervosa and bulimia and for the management of some cases of IDDM with unstable metabolic control.

Adolescent↗
PubMed1984

Vocal responses to left visual stimuli following forebrain commissurotomy.

Four forebrain commissurotomized patients, 12-15 yr post-surgery, along with one partially commissurotomized and three normal control subjects, were presented with a variety of stimuli to either the LVF (left visual field) or RVF. Three of four "split-brain" patients could name LVF numbers and two of four could name LVF letters. Irrespective of their accuracy, and unlike control subjects, all "split-brain" patients named LVF stimuli about twice as slowly as RVF stimuli. In addition, three of four patients could vocally categorize LVF stimuli into two classes (yes-no, odd-even, more or less than five). In this case, like the control subjects, they respond to LVG stimuli as quickly as to RVF stimuli. The results support an hypothesis that "split-brain" patients may transfer information from the right to the left cerebral hemisphere when making two-choice verbal categorizations of LVF stimuli, but are able to name some simple LVF stimuli directly from the right hemisphere. Combining categorization and naming tasks, however, can elicit interference, suggesting that the two tasks are not completely autonomous.

Brain↗
PubMed1984

Bilateral visual cross-integration by human forebrain commissurotomy subjects.

Four forebrain commissurotomized patients were compared with one partially commissurotomized control subjects on their ability to cross-compare simultaneously flashed bilateral visual stimuli (colors, schematic faces, numbers, letters, patterns) as same or different, or to name the two stimuli. Two of the four patients were able to cross-compare some or all of the stimuli verbally, while another patient could name the two stimuli but not separately determine same-difference. It is hypothesized that (1) each cerebral hemisphere is capable of making separate verbal naming responses, and (2) brainstem interconnections between the 'disconnected' hemispheres allow some patients to integrate bilateral visual stimuli and make accurate same-different judgments.

Brain↗
PubMed1983

Filicidal behavior: behavioral correlates and role of sensory systems.

The administration of para-chloro-D,L-phenylalanine (PCPA) produces a high incidence of filicidal (pup-killing) behavior in female rodents. The present series of experiments determined the major behavioral, sensory, and temporal correlates of filicidal behavior in nulliparous adult Sprague-Dawley female rats. In Experiment 1, behavioral episodes involving the interaction of test pups and PCPA-induced filicidal females were videotaped, and subsequent analyses of behaviors related to locating, carrying, mauling, attacking, gnawing, and consuming the prey object were performed. Analysis indicated that the primary behavioral correlates in the PCPA animals included location, initiation of the attack (mauling), and killing of the pup (filicide). Only location was observed in control animals. Experiment 2 evaluated the effects of sensory impairments on location, mauling, and filicide. Sensory impairment occurred at 24 days of age for enucleation and 62 days of age for olfactory bulbectomies and/or auditory destruction. Animals were injected either at 110 or 130 days of age with PCPA for three consecutive days and tested for filicide for five additional days. Locating of the test pup was not affected by sensory impairment. Mauling was reduced significantly in the enucleation/auditory destructed animals. Filicide was significantly lower in animals with visual/auditory destruction, and, compared to controls, was reduced in all sensory impaired groups.

Aggression↗