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Biomedical subjects

L Larsen

Publications and source records attributed to L Larsen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Thermoanaerobacter mathranii sp. nov., an ethanol-producing, extremely thermophilic anaerobic bacterium from a hot spring in Iceland.

The extremely thermophilic ethanol-producing strain A3 was isolated from a hot spring in Iceland. The cells were rod-shaped, motile, and had terminal spores; cells from the mid-to-late exponential growth phase stained gram-variable but had a gram-positive cell wall structure when viewed by transmission electron microscopy. Strain A3 used a number of carbohydrates as carbon sources, including xylan, but did not utilize microcrystalline cellulose. Fermentation end products were ethanol, acetate, lactate, CO2, and H2. The temperature optimum for growth was between 70 and 75 degrees C, and growth occurred in the range of 50-75 degrees C. The pH range for growth was 4.7-8.8, with an optimum at pH 7.0. Strain A3 was sensitive to tetracycline, chloramphenicol, penicillin G, neomycin, and vancomycin at 100 mg/l but was not sensitive to chloramphenicol and neomycin at 10 mg/l, which indicates that strain A3 belongs to the eubacteria. Addition of 50.66 kPa H2 or 2% NaCl did not affect growth. The isolate grew in the presence of exogenously added 4% (w/v) ethanol. The G+C ratio was 37 mol%. 16S rDNA studies revealed that strain A3 belongs to the genus Thermoanaerobacter. Genotypic and phenotypic differences between strain A3 and other related species indicate that strain A3 can be assigned to a new species, and the name Thermoanaerobacter mathranii is proposed.

Bacteria, Anaerobic↗
PubMed1996

Concerns, affect, and cognitive disruption following completion of radiation treatment for localized breast or prostate cancer.

PURPOSE/OBJECTIVES: To describe concerns, cognitive disruption, and affect following the completion of radiation treatment (RT) for localized breast or prostate cancer. DESIGN: Cross-sectional, descriptive. SETTING: Two RT centers associated with a university hospital. SAMPLE: Patients who completed RT for prostate (n = 9) or breast cancer (n = 11). The mean age of the sample is 64 years. Ninety percent are Caucasian, 80% are married, 50% are of Latter-day Saint faith, and 50% are retired. All had early stage disease, with a mean of 20 months post-RT. METHODS: One-time interview using qualitative methods and the Life Orientation Test, Revised Impact of Events Scale, state scale of the Positive and Negative Affect Schedule, satisfaction items of the Sarason Social Support Questionnaire, and Side Effect Severity Checklist. MAIN RESEARCH VARIABLES: Frequency of intrusive thoughts or avoidant behavior, positive and negative affect, dispositional optimism, satisfaction with social support, severity of side effects, and themes extracted from semistructured interviews. FINDINGS: Most subjects had unexpected intrusive thoughts about cancer; more than one-third avoided reminders of cancer. The level of positive affect was high, as was optimism. The level of negative affect was low. Subjects' satisfaction level with social support was high. Fatigue was the most frequently reported continuing side effect. Relative optimism, acceptance, vigilance, and trust of healthcare providers were major themes. Avoidance, comparison, maintaining normalcy, and information seeking were common coping strategies. CONCLUSIONS: Subjects perceived themselves to be doing well. Fatigue was the most common long-term side effect. Subjects continued to seek information. Symptom vigilance and interpretation were important, as were having a positive outlook and maintaining normalcy. IMPLICATIONS FOR NURSING PRACTICE: Nurses must acknowledge the potential for concerns about symptoms and continuing side effects and what they mean for the patient. Clinicians need to provide accurate information about common post-treatment experiences. Clinicians also must remember that subjects have vivid recollections of both positive and negative interactions with healthcare providers.

Adaptation, Psychological↗
PubMed1995

Socio-economic status of AIDS patients.

The charts of 187 patients diagnosed at Hvidovre University Hospital, Copenhagen from 1981 through 1989 as having AIDS were reviewed retrospectively in order to examine the extent of their employment and alternative sources of income during the first 2 years after diagnosis. At the time of diagnosis, 50% were actively employed, 15% were on sick leave, and 19% were receiving a pension. The remaining 16% were either receiving unemployment benefits, on welfare, students, or supported by family or friends. The proportion of patients actively employed declined to 22% one month after the time of diagnosis. After 2 years, only 6% still worked, while 22% had a pension. Sixty-seven percent had died. The major source of income during these first 2 years after diagnosis was a pension, most often a disability pension. During this period the total average disbursement of public allowances per patient amounted to US$16,150. As shown here, the work capacity of AIDS patients is quite low, and alternative sources of income must be provided.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Tamoxifen and bone metabolism in postmenopausal low-risk breast cancer patients: a randomized study.

PURPOSE: This trial was undertaken to evaluate the effect of adjuvant tamoxifen on bone metabolism in postmenopausal women undergoing surgery for low-risk breast cancer. PATIENTS AND METHODS: In an open trial, 25 women were randomized to receive tamoxifen 30 mg/d for 2 years, and 25 women constituted the control group. Twenty women treated with tamoxifen and 23 women in the control group provided data for the analysis. Inclusion criteria were operation for low-risk breast cancer and cessation of menstruations for more than 1 year. Exclusion criteria were presence of metastases, disorders of bone metabolism, contraindications against tamoxifen, use of drugs with influence on bone metabolism, ailments that made bone mineral measurements impossible, and age greater than 65 years. Repeated measurements of bone mineral density and content at the lumbar spine and forearms, serum alkaline phosphatase, phosphate, and ionized calcium were performed in all patients. RESULTS: Lumbar spine bone mineral density increased during the first year in women treated with tamoxifen and then stabilized, compared with decreased bone mineral density in the control group (P = .00074). Bone mineral content at the forearms remained almost stable in tamoxifen-treated women compared with a decrease in the control group (P = .024). Serum alkaline phosphatase, phosphate, and ionized calcium decreased in the tamoxifen group (P < .00001, P = .002, and P = .002, respectively). CONCLUSION: Tamoxifen has estrogen-like effects on bone metabolism that result in an increase and stabilization of bone mineral density in the axial skeleton and a stabilization of bone mineral content in the appendicular skeleton.

Absorptiometry, Photon↗
PubMed1993

Functional status of stroke patients in long-term care--a basis for development of rehabilitation and care.

Thirty persons who had remained in long-term care for one year or more post-stroke were assessed with respect to motor function, cognitive, perceptual, and communication ability and ADL capacity. Before the stroke they had lived an independent life, although 40% suffered from cardiovascular disease. At the follow-up, all patients had severe impairments due to the brain damage. None could walk or stand independently, ten could not call for help or attract attention in any way, and 13 could not take part in a conversation. Eleven patients had severe pain in spite of treatment with analgesics. Pain treatment and training methods that can reduce dependence and improve the quality of life for patients like these need to be developed. More appropriate assessment instruments for this patient group have to be constructed to make evaluation of training and care possible.

Activities of Daily Living↗
PubMed1993

Sudden death in idiopathic dilated cardiomyopathy: role of ventricular arrhythmias.

Sudden cardiac death (SCD) is associated with idiopathic congestive cardiomyopathy (IDCM) and most commonly is due to ventricular tachyarrhythmias. The recurrence rate of SCD in the absence of specific therapy is thought to be around 20%-30% per year. Asymptomatic and symptomatic ventricular arrhythmias are common in patients with IDCM and the direct causal link of such arrhythmias with SCD in IDCM patients remains to be established. Furthermore, therapy directed at suppressing these ventricular arrhythmias has not been shown to decrease the incidence of SCD. Various approaches such as ambulatory monitoring, electrophysiological testing, signal-averaged electrocardiogram, and hemodynamics have met with variable success in identifying patients prone to SCD. Additionally, therapeutic approaches to prevent SCD in IDCM patients have produced equivocal results. This article reviews the published studies addressing the causal link of ventricular arrhythmias to sudden death in patients with IDCM and the attempts to decrease the incidence of sudden.

Arrhythmias, Cardiac↗
PubMed1991

Direct derivation of conditionally immortal cell lines from an H-2Kb-tsA58 transgenic mouse.

Studies on cell lines have greatly improved our understanding of many important biological questions. Generation of cell lines is facilitated by the introduction of immortalizing oncogenes into cell types of interest. One gene known to immortalize many different cell types in vitro encodes the simian virus 40 (SV40) large tumor (T) antigen (TAg). To circumvent the need for gene insertion in vitro to generate cell lines, we created transgenic mice harboring the SV40 TAg gene. Since previous studies have shown that TAg expression in transgenic mice is associated with tumorigenesis and aberrant development, we utilized a thermolabile TAg [from a SV40 strain, tsA58, temperature sensitive (ts) for transformation] to reduce the levels of functional TAg present in vivo. To direct expression to a broad range of tissues, we used the mouse major histocompatibility complex H-2Kb promoter, which is both widely active and can be further induced by interferons. tsA58 TAg mRNA was expressed in tissues of all animals harboring the hybrid construct. Development of all tissues was macroscopically normal except for thymus, which consistently showed hyperplasia. Fibroblast and cytokeratin+ thymic epithelial cultures from these mice were readily established without undergoing crisis and were conditionally immortal in their growth; the degree of conditionality was correlated with the levels of tsA58 TAg detected. One strain of H-2Kb-tsA58 mice has been bred through several generations to homozygosity and transmits a functional copy of the transgene.

Animals↗