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Biomedical subjects

J Christenson

Publications and source records attributed to J Christenson.

54 records · Page 3Linked to original sources
PubMed1984

Interpretation of susceptibility testing of ceftriaxone.

Susceptibility of a variety of bacterial isolates to ceftriaxone was determined by Kirby-Bauer assays using 30 micrograms ceftriaxone disks and by microdilution (MIC) assays using standard procedures. The relation between zones of inhibition and MICs was expressed by the following regression equation: zone diameter = 22.98-2.653 In (MIC). Using this regression line and the breakpoints estimated from ceftriaxone concentrations in plasma 12 to 24 hours after 1- and 2-g doses, the susceptibility of a pathogen to ceftriaxone was classified as follows: susceptible-zone 16 mm or greater, MIC 16 micrograms/ml or less; moderately susceptible-zone 13 to 15 mm, MIC 17 to 63 micrograms/ml; resistant-zone 12 mm or less, MIC 64 micrograms/ml or greater. These breakpoints were used to determine the susceptibility of organisms isolated during clinical studies in the United States. The correlation between the in vitro results and the bacteriologic outcomes achieved in the clinical cases was analyzed to assess the suitability of the chosen breakpoints. The results of the disk assays were correctly predictive of bacteriologic responses with 1,388 of 1,513 organisms (91.7 percent), whereas the results of dilution assays correctly predicted the response with 897 of 941 organisms (95.3 percent). The correlation between in vitro results and bacteriologic outcome in patients treated with ceftriaxone was equivalent or superior to that achieved in patients treated with the comparative agents cefamandole and cefazolin. Thus, the chosen cutoff points for indicating susceptibility and resistance to ceftriaxone appear to be suitable and highly predictive of clinical success.

Bacteria↗
PubMed1982

Bacterial contamination of donor corneas stored in McCarey-Kaufman medium.

A new method is presented for culturing eye bank corneas stored in McCarey-Kaufman (M-K) medium. Of 30 donor corneoscleral rims, each was cultured in three ways: a swab on the M-K medium, a swab of the cut edge, and by culture of a 0.2 micron filter through which an aliquot of solution had been passed and washed of any antibiotic. We found a much higher rate of positive cultures using the latter method than has previously been reported in the literature.

Bacteriological Techniques↗
PubMed1977

Distribution of intravenously injected 201thallium in the legs duging walking. A new test for assessing arterial insufficiency in the legs.

There is a multitude of method for assessing the efficiency of the arterial circulation in the legs. Most of these methods can give conclusive information about the patency of the main arteries in the leg; the level of an arterial obstruction can also be estimated. However, none of these methods provides a direct estimate of the functional importance of arterial lesions of light to moderate severity. The present report describes preliminary findings of the distribution of intravenously injected 201Thallium, a potassium analogue, in the legs during exercise provoking symptoms of ischemia. From this pilot study the general impression is that the thallium uptake pattern corresponds well with the clinical, physiologic, and angiographic picture.

Arterial Occlusive Diseases↗
PubMed1977

Abdominal aortic aneurysms: should they all be resected?

A retrospective study has been carried out on 124 consecutive patients with abdominal aortic aneurysms admitted during the period 1960-74. The mortality rate after emergency operation was 56 per cent and after elective operation 15 per cent. As in other vascular centres during these years the mortality rate has decreased among electively operated patients. We have tried to answer two questions: which patients without signs of rupture should undergo operation and which patients with a ruptured aneurysm should not be operated upon?

Aorta, Abdominal↗
PubMed1977

Synthetic arterial grafts. I. General complications.

A retrospective study of 113 patients operated upon with synthetic arterial grafts was made. This report reviews our experience during the past 15 years as a basis for evaluation of complications of abdominal aortic surgery and investigation of methods for preventing some of the major complications of grafting procedures. The early mortality, within the first 10 postoperative days, is also discussed. The most usual complications were graft thrombosis and infection.

Adult↗
PubMed1977

Synthetic arterial grafts. II. infection complications.

A retrospective study of 91 patients with synthetic arterial grafts was made. The investigation showed that infection of synthetic arterial grafts is a serious and life-threatening complication. Of our 14 infected cases, 5 patients were amputated and 4 patients died. The incidence of infection is significantly increased when the anastomosis is performed through a groin incision. In addition the management of patients with infected graft is discussed and two cases are reported.

Aneurysm↗
PubMed1977

Infection complications after thrombectomy in deep venous thrombosis.

In acute iliofemoral vein thrombosis thrombectomy with a temporary AV-fistula is an alternative treatment to induced fibrinolysis and anticoagulation. Reviewing our results we have found an extremely high incidence of wound infections. In 36 patients thrombectomy with temporary AV-fistula has been performed. 31% of these had a postoperative wound infection. The mean hospital stay for the infected patients was 25 days compared to 10 days for the non-infected patients. In 26 patients a second, elective operation with closure of the AV-fistula was performed. 15% of these patients developed postoperative wound infection. The mean hospital stay for the infected patients was 18 days compared to 5 days for the non-infected patients.

Adult↗
PubMed1976

Detection of drugs of abuse by radioimmunoassay: a summary of published data and some new information.

We review the status of radioimmunoassays for detection of abused drugs. Individual assays with use of 125I-labeled antigens are all performed in an identical manner and can be completed in 30 min to 1 h. Combined assays for simultaneous detection of two or more such drugs or assays in which a tritium-labeled antigen is used require 1-2 h for completion. All tests can be performed with 0.1 ml or less of specimen. The assays involving 125I reliably detect urinary concentrations of, per liter, 40-100 mug of morphine, 100 mug of barbiturates, methadone, methaqualone, or benzoylecgonine, and 1000 mug of amphetamine. The assay for morphine involving 3H detects 60 mug/liter. Each assay is capable of providing a qualitative and quantitative estimate of the drugs sought. The 125I-labeled antigens have a usable shelf life of at least two to four months after the antigen is iodinated; the tritium assay is stable for six months. The assays can be performed with use of paper discs that have been suspended in urine and then dried, in place of the liquid specimen. The assays appear to be equally applicable to detection of drugs in urine, blood, saliva, and tissues. All of them are done at ambient temperature and can be used equally well for emergency (stat) tests or mass screening. Except for the benzoylecgonine assay, the clinical reliability of these tests has been demonstrated.

Amphetamine↗
PubMedDate not supplied

A new system for sternal intraosseous infusion in adults.

BACKGROUND: Intraosseous (IO) infusion provides an alternative route for the administration of fluids and medications when difficulty with peripheral or central lines is encountered during resuscitation of critically ill and injured patients. OBJECTIVE: To report the first 50 uses of a new system for emergency IO infusion into the sternum in adults, the Pyng F.A.S.T.1 IO infusion system. METHODS: Six emergency departments and five prehospital emergency medical services (EMS) sites in Canada and the United States provided clinical and/or research data on their use of the IO system in a pilot study of success rates, insertion times, and complications. Indications for use included adult patient, urgent need for fluids or medications, and unacceptable delay or inability to achieve standard vascular access. A basic data set was standardized for all sites, and some sites collected additional data. RESULTS: The overall success rate for achieving vascular access with the system was 84%. Success rates were 74% for first-time users, and 95% for experienced users. Failure to achieve vascular access occurred most frequently in patients (5 of 9) described subjectively by the user as "very obese," in whom there was a thick layer of tissue overlying the sternum. Mean time to achieve vascular access was 77 seconds. Flow rates of up to 80 mL/min were reported for gravity drip, and more than 150 mL/min by syringe bolus. Pressure cuffs were also used successfully, although fluid rate was controlled by clamping the line. Further research on flow rates is needed. No complications or complaints were reported at two-month follow-up. CONCLUSION: These early data indicate that sternal IO infusion using the new F.A.S.T.1 IO system may provide rapid, safe vascular access and may be a useful technique for reducing unacceptable delays in the provision of emergency treatment.

Adolescent↗
PubMedDate not supplied

Healing the wounds of war: the Vietnam veteran after Operation Desert Storm.

TOPIC: How Operation Desert Storm, and the positive response of the public to this crisis, seemed to stimulate and heighten unresolved feelings for many Vietnam veterans. PURPOSE: To show that understanding the lived experiences of Vietnam veterans, at time when men and women returning from Operation Desert Storm were welcomed back by their country, would allow for the development of more effective treatment approaches in working with Vietnam veterans. METHODS: Personal interviews, during and immediately following Operation Desert Storm, with 12 men who served in Vietnam. FINDINGS: Themes identified and described by Vietnam veterans included repressed fear, shame, isolation and loneliness, disillusionment, permanence of memories, and acceptance. CONCLUSION: Further exploration and analysis of these themes is recommended.

Adaptation, Psychological↗
PubMedDate not supplied

Lesion detectability as a function of pulse-height selection for dynamic imaging with 99mTc.

Previous studies on pulse-height selection for scintillation cameras have been concerned with static imaging or asymmetric window settings around the photo peak. For count densities typical of those encountered in flow studies and for the customary symmetric window it is shown here, both computationally and experimentally, that a window setting in the range of 25-35% provides the maximum lesion detectability rate for lesions of 0.5- to 2.0-cm diameter.

Liver Diseases↗
PubMedDate not supplied

Persistent and severely mentally ill clients' perceptions of their mental illness.

This qualitative, exploratory study examines severely mentally ill clients' perceptions of their illness and the effects of this illness on their lives. The major purpose of this study was to explore the lived experiences of severely mentally ill clients. Subjects included 15 clients in an out patient mental health clinic in a veterans' hospital in the upper midwestern United States. A phenomenologic methodology was used, with subjects being interviewed until common themes emerged. The data were analyzed utilizing a seven-step method. Four major themes emerged in the data analysis. Identification of these themes provided a meaningful way to synthesize the data and identify those concepts that best capture and name the personal perceptions of severely and persistently mentally ill people. The four themes identified were stigmatization and the resulting alienation, loss, a pervasive feeling of distress, and acceptance on two dimensions (a personal acceptance of having a mental illness and a need for acceptance by others). Although the individuality of each client was evident in the data obtained, each theme represents a collective perspective that emerged from the analysis of the data.

Adult↗
PubMedDate not supplied

Effects of organizational change in the medical intensive care unit of a teaching hospital: a comparison of 'open' and 'closed' formats.

OBJECTIVE: To compare the effects of change from an open to a closed intensive care unit (ICU) format on clinical outcomes, resource utilization, teaching, and perceptions regarding quality of care. DESIGN: Prospective cohort study; prospective economic evaluation. SETTING: Medical ICU at a university-based tertiary care center. For the open ICU, primary admitting physicians direct care of patients with input from critical care specialists via consultation. For the closed ICU, critical care specialists direct patient care. PATIENTS: Consecutive samples of 124 patients admitted under an open ICU format and 121 patients admitted after changing to a closed ICU format. Readmissions were excluded. MAIN OUTCOME MEASURES: Comparison of hospital mortality with mortality predicted by the Acute Physiology and Chronic Health Evaluation II (APACHE II) system; duration of mechanical ventilation; length of stay; patient charges for radiology, laboratory, and pharmacy departments; vascular catheter use; number of interruptions of formal teaching rounds; and perceptions of patients, families, physicians, and nurses regarding quality of care and ICU function. RESULTS: Mean +/- SD APACHE II scores were 15.4 +/- 8.3 in the open ICU and 20.6 +/- 8.6 in the closed ICU (P=.001). In the closed ICU, the ratio of actual mortality (31.4 percent) to predicted mortality (40.1 percent) was 0.78. In the open ICU, the ratio of actual mortality (22.6 percent) to predicted mortality (25.2 percent) was 0.90. Mean length of stay for survivors in the open ICU was 3.9 days, and mean length of stay for survivors in the closed ICU was 3.7 days (P=.79). There were no significant differences between periods in patient charges for radiology, laboratory, or pharmacy resources. Nurses were more likely to say that they were very confident in the clinical judgment of the physician primarily responsible for patient care in the closed ICU compared with the open ICU (41 percent vs 7 percent; P<.Ol), and nurses were the group most supportive of changing to a closed ICU format before and after the study. CONCLUSIONS: Based on comparison of actual to predicted mortality, changing from an open to a closed ICU format improved clinical outcome. Although patients in the closed ICU had greater severity of illness, resource utilization did not increase.

APACHE↗