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Biomedical subjects

C Bowers

Publications and source records attributed to C Bowers.

At least 19 recordsLinked to original sources
PubMed2001

What determines whether observers recognize targeted behaviors in modeling displays?

Observational learning is based on a critical assumption that trainees can and do recognize critical modeled behaviors. This assumption has been virtually untested in applied settings. We studied the effects of work experience and instructions on the ability of 59 observers to recognize target behaviors in an observational learning paradigm similar to existing ones. Additionally, we investigated the effects of two key factors that were hypothesized to affect the recognition process in observational learning. The results indicated that only observers who had a minimum of work experience (i.e., intermediate and experienced observers in the study) were able to consistently recognize targeted behaviors. Additionally, recognition was influenced by the level of detail of instructions given to the participants. Finally, characteristics of the modeled behaviors greatly affected recognition: Overall, examples of negative behaviors were better recognized than were positive examples. Behaviors whose consequence was shown were also better recognized than those that were neither reinforced nor punished in the video. The results are discussed in terms of their implications for the design of observational learning as a training strategy in complex and applied social learning situations. The applications of this work include the design of training, and the training of evaluators and observers.

Aviation↗
PubMed2000

A novel syndrome of radiation-associated acute myeloid leukemia involving AML1 gene translocations.

AML1 is a transcriptional activator that is essential for normal hematopoietic development. It is the most frequent target for translocations in acute leukemia. We recently identified 3 patients in whom pancytopenia developed almost 50 years after high-level radiation exposure from nuclear explosions during or after World War II. In all 3 patients, acute myeloid leukemia (AML) eventually developed that had similar characteristics and clinical courses. Cytogenetics from the 3 patients revealed a t(1;21)(p36;q22), a t(18;21)(q21;q22), and a t(19;21)(q13.4;q22). By fluorescent in situ hybridization (FISH), all 3 translocations disrupted the AML1 gene. Two of these AML1 translocations, the t(18;21) and the t(19;21), have not been reported previously. It is possible that the AML1 gene is a target for radiation-induced AML. (Blood. 2000;95:4011-4013)

Acute Disease↗
PubMed2000

Decision making in dual-task environments: analysis of hemispheric competition effects.

Performance degradations in multitasking situations have been reported frequently as a predictable effect of competition that arises from different processing demands whose hemispheric locations are too proximal. This model might be useful in explaining performance deficits in complex workplaces. To test this assertion, a laboratory study was designed to create an analogue of the processing demands required by a tactical decision-making task performed by 24 right-handed men. Vocalization, dichotic listening and decision-making performance were assessed under single- and dual-task conditions. The results were consistent with the predictions from hemispheric competition in the case of dichotic listening but not with vocalization. The results are discussed in terms of their implications for both research and systems design.

Auditory Perception↗
PubMed1998

Can practice guidelines safely reduce hospital length of stay? Results from a multicenter interventional study.

BACKGROUND: Although practice guidelines about appropriate lengths of stay have been widely promulgated, their effects on patient outcomes are not clear. Our objective was to study the effects of length of stay practice guidelines on patient outcomes. PATIENTS AND METHODS: We performed a prospective, nonrandomized, interventional trial in six geographically distributed hospitals, among consecutively hospitalized "low-risk" patients with total hip replacement, hip fracture, or knee replacement. Case managers provided physicians with patient risk information based on guideline recommendations. We measured length of stay, compliance with recommended guideline length of stay, health status, hospital readmission rates, return to emergency department, return to work and recreation, and patient satisfaction. RESULTS: A total of 560 patients were included in the study. For patients with knee replacement, there was a statistically significant increase in practice guideline compliance (27% baseline versus 53% intervention, P <0.0001) and reduction in length of stay (5.2 days versus 4.6 days, P <0.001) when compared with the baseline period. For hip replacement patients, there similarly was an increase in practice guideline compliance (66% baseline versus 82% intervention, P = 0.01) and reduction in length of stay (5.1 days versus 4.8 days, P = 0.03). Significant reductions in length of stay were not observed for patients recovering after hip fracture despite a significant increase in guideline compliance. There were few statistically significant changes in patient outcomes related to reductions in lengths of stay, including health status, hospital readmission rates, return to emergency department, return to work and recreation, and patient satisfaction. For patients undergoing hip replacement, very short lengths of stay (shorter than the guideline recommendation) were associated with an increased rate of discharging patients to nursing homes and rehabilitation facilities (21% versus 7%, P = 0.01), and hip fracture patients with very short lengths of stay required more visits to the doctor after discharge (56% versus 25%, P = 0.04). CONCLUSION: Reductions in lengths of stay were most often associated with no significant change in patient outcomes. However, very short lengths of stay were associated with increased intensity of care following discharge for patients undergoing hip surgery, indicating possible cost shifting (the cost incurred by transferring patients to rehabilitation facilities may have been greater than had the patients remained in the acute care hospital for an additional 1 or 2 days and been sent directly home). These results emphasize the importance of monitoring the effects of cost containment and other systematic efforts to change patient care at the local level.

Aged↗
PubMed1998

Using a nursing framework to measure client satisfaction at a nurse-managed clinic.

There is considerable literature on nurse-managed clinics and client satisfaction with nurse practitioner care. However, the methodological weaknesses of satisfaction measures which are often used limits confidence in the study findings. Satisfaction measures typically lack reliability analysis and/or have limited validity testing. This descriptive, correlational study investigates the validity and reliability of a new measure, the Client Satisfaction Tool (CST) and determines the degree of satisfaction that clients at a newly established senior health clinic had with the primary care services they were receiving. The CST is based upon Cox's Interactional Model of Client Health Behavior and thus was explicitly developed to measure client satisfaction with a nurse practitioner model of care. A convenience sample of 38 clients completed the CST. Responses to the CST indicated that users of the senior health clinic were satisfied with the care they received. Reliability testing showed that the tool has high internal consistency (Chronbach's alpha was 0.956) and high stability (r = 0.974). Construct validity testing with measures of perceived health changes showed that the tool has both convergent (r = 0.599, P < 0.01) and divergent (r = 0.194, P > 0.10) validity. Thus, the CST is a methodologically sound measure of client satisfaction that can be used in future research that examines client satisfaction with nurse practitioner care.

Aged↗
PubMed1998

Automation, task difficulty, and aircrew performance.

The effects of an automated system on team processes and performance were assessed in a laboratory simulation. Two-person crews were required to fly a complex emergency-response scenario under conditions of low and high workload. These flights were completed with or without the aid of an autopilot. The results indicated that the autopilot was effective in reducing subjective workload. However, the automation was associated with improved performance on only 1 of 4 performance measures. Furthermore, it was observed that problem-solving performance was worse in the autopilot condition during the high-workload flights. Investigation of crew process data indicated that workload savings afforded by the autopilot might have been invested in more explicit coordination. The results are discussed in terms of their implications for military aviators' performance, system design, and team training.

Adult↗
PubMed1998

Prevalence of ethanol consumption may be higher in women than men in a university health service population as determined by a biochemical marker: whole blood-associated acetaldehyde above the 99th percentile for teetotalers.

To estimate ethanol consumption by university students attending a student health facility, a biochemical marker of alcohol intake [whole blood associated acetaldehyde (WBAA)] was quantified by fluorimetric HPLC. Over a two year period we studied blood samples, coded by date and sex, from 645 females and 332 males, and compared the results to previously established reference ranges for teetotalers by sex. Men had higher absolute values for WBAA than women (9.9 versus 9.5 microM in the present study). However, significantly greater numbers of women (74%) than men (44%) had WBAA levels above the 99th percentile for teetotalers. Variations occurred during the academic year, with significant elevations occurring in the late fall and winter months. Testing of WBAA levels in a student health service may be important especially for women to facilitate counseling on the dangers of alcohol abuse.

Acetaldehyde↗
PubMed1998

A prospective, multicenter study of a pneumonia practice guideline.

OBJECTIVE: To study the effect of a length of stay practice guideline on patient outcomes. DESIGN: A prospective, nonrandomized, interventional trial. SETTING: Six geographically distributed hospitals. PATIENTS: Two hundred forty-two consecutively hospitalized "low-risk" patients with pneumonia. MEASUREMENTS AND RESULTS: One hundred fifty-two patients (63%) completed the mailed postdischarge survey and were included in the analysis. Data were prospectively collected for 85 patients from the baseline observation period (B) and 67 patients from the intervention period (I). During the I, case managers provided physicians with patient risk information based on guideline recommendations. There was no significant change in guideline compliance (B vs I: 76.5% vs 83.6%; p=0.32) or length of stay (B vs I: 3.5 days [95% confidence interval, 3.2 to 3.8] vs 3.6 days [95% confidence interval, 3.3 to 4.0]). Also, there were no statistically significant effects of the intervention on patient outcomes, care following hospital discharge, and patient satisfaction scores. CONCLUSION: Patients in this study often had shorter lengths of stay than recommended by the practice guideline. This suggests that the external environment may have had a greater effect on physician behavior and length of stay than the practice guideline itself. Moreover, it demonstrates the importance of continuous assessment of physician practices immediately prior to, during, and after application of the clinical practice guideline.

Activities of Daily Living↗
PubMed1997

Randomized comparison of G-CSF + GM-CSF vs G-CSF alone for mobilization of peripheral blood stem cells: effects on hematopoietic recovery after high-dose chemotherapy.

Fifty patients with either lymphoid or selected solid tumor malignancies were apheresed an identical number of times for PBSC collection after being randomized to receive either G-CSF 10 microg/kg/day alone (arm I), or G-CSF at the same dose with GM-CSF 5 microg/kg/day (arm II). Growth factor(s) was/were given as the stem cell mobilizing agent for 5 days before the start of PBSC collection, and were continued throughout the 4 days of apheresis. Aspiration and cryopreservation of autologous bone marrow occurred on day 3 or 4 of growth factor(s). Thirty-one of 50 patients received one cycle only at time of evaluation, and 19 patients received two cycles of HDCT, each supported with PBSC with or without autologous bone marrow. No patients received growth factors post-autologous stem cell transplant, unless the absolute neutrophils count (ANC) failed to recover to > or = 100/microl by day +18 post-transplant. The median number of days to recovery of ANC to 100/microl, 500/microl and 1000/microl, and of platelet counts to 20000/microl, 50000/microl and 100000/microl after either cycle 1 or cycle 2 of HDCT and the number of febrile days and platelet and PRBC transfusion requirements was not significantly different between the two arms of the study. The duration of hospitalization was similar between study arms for cycle 1 of HDCT, but was 3.5 days less with arm II compared to arm I (P = 0.0248) for cycle 2 of HDCT. The bone marrow buffy coat and PBSC product mononuclear cell count (x 10(8)/kg) and CD34+ cell count (x 10(6)/kg) collected by each method of stem cell mobilization was not significantly different. There is questionable clinical benefit with PBSC products mobilized with the combination of G-CSF and GM-CSF vs G-CSF alone. Perhaps different dosages, schedules, or other growth factor combinations with G-CSF might enhance these differences.

Adult↗
PubMed1995

Reduced-size antagonists of luteinizing hormone-releasing hormone active in vitro.

A series of reduced-size analogs of LHRH was designed with the length varying from nine to two amino acids. These compounds were tested in vitro for the LH suppression in cultured rat pituitary cells treated with 1 ng of LHRH. The best analogs were also tested in vivo for their antiovulatory activity in rats. It appeared that terminal amino acids as well as the presence of Arg or ILys in the sequence are both crucial for the antagonism. The most potent antagonist in this series was a heptapeptide, AcDNal-Ser-Tyr-DNal-Leu-Arg-ProNHEt, which completely inhibited LH release at the dose 0.1 microgram and inhibited ovulation at 1000 micrograms/rat. For fragments shorter than heptapeptide the inhibition of LH release was observed at the dose 100 micrograms of the analog.

Amino Acid Sequence↗
PubMed1995

Impact of automation on aircrew communication and decision-making performance.

Increasing levels of automation are being introduced into the cockpit. Yet, it is difficult to predict the impact of these automatic systems on other elements of flight, such as crew communication and the ability to arrive at an effective decision. This study attempted to clarify the relation among these variables. Forty-eight pilots were assigned to two-person crews and asked to fly a simulated mission in either automated or manual conditions using a low-fidelity simulator. The scenario was designed to require crewmembers to arrive at a collective decision based on information obtained about an evolving simulated disaster. The results indicated that the introduction of automation was not associated with better performance. However, several significant differences were observed in the communications of crews flying in the automated versus manual conditions. The results are discussed in terms of their implications for communications training for advanced technology aircraft.

Adult↗
PubMed1994

Novel, potent luteinizing hormone-releasing hormone antagonists with improved solubility in water.

A series of luteinizing hormone-releasing hormone antagonists with new substitutions in position 6 or positions 5 and 6 that included lysine acylated at the epsilon-amino group with different heterocyclic carboxylic acids or amino-substituted heterocyclic carboxylic acids was synthesized. These novel analogs wee synthesized on a solid-phase support via the acylation of lysine residue in otherwise protected resin-bound peptides. All analogs were tested in the rat antiovulatory assay (AOA) and the best of them in in vitro histamine release assay. Introduction of lysine acylated with amino-substituted heterocyclic carboxylic acids yielded several water-soluble antagonists with good therapeutic ratio (high AOA to low histamine releasing activity). The best antagonist in terms of activity, histamine release, and solubility was nictide: NAcDNal-DCpa-DPal-Ser-PicLys-D(6ANic)-Orn- Leu-ILys-Pro-DAlaNH2 (6ANic = 6-aminonicotinoyl).

Amino Acid Sequence↗
PubMed1994

Irreversible, severe congestive cardiomyopathy occurring in association with interferon alpha therapy.

Interferon alpha is a biologic agent with demonstrated anti-tumor activity in a variety of hematologic and solid malignancies. Many patients treated with interferon experience acute toxicity manifested as a flu-like syndrome of fever, chills, myalgias, and malaise. However, fatigue, anorexia, bone marrow suppression, nausea, vomiting, dizziness, and confusion may also occur. Cardiotoxicity is a rare complication of interferon therapy that most frequently presents as transient episodes of hypotension and tachycardia, with few significant life-threatening cardiovascular effects reported. A small number of cases of suspected interferon-induced cardiomyopathy, all of which improved after discontinuing interferon, have recently been documented. We report a patient with multiple myeloma who developed severe congestive cardiomyopathy while receiving interferon alpha that did not reverse subsequent to discontinuation of interferon therapy. Although the patient had previously received doxorubicin, the presence on endomyocardial biopsy of a prominent intracellular lipid accumulation within myocytes and only grade 2 anthracycline cardiotoxicity suggested that other or additional factor(s) contributed to the severity of this patient's cardiomyopathy. Etiologies of cardiac dysfunction other than interferon and doxorubicin were excluded. While a direct cause-effect relationship between interferon alpha and irreversible congestive cardiomyopathy cannot be firmly established in this case report, patients who either concurrently or sequentially receive interferon and anthracyclines should be carefully monitored for evidence of cardiac toxicity.

Combined Modality Therapy↗
PubMed1993

Dose escalation of mitoxantrone given with thiotepa and autologous bone marrow transplantation for metastatic breast cancer.

High-dose chemotherapy given with autologous bone marrow support has resulted in significant tumor responses in the majority of patients with metastatic breast cancer, a minority of which are durable. To improve on these results, we are developing high-dose preparative regimens which may be given in successive cycles, each with autologous bone marrow transplantation (ABMT), over a short duration. In this report, 44 patients with metastatic breast cancer were treated with thiotepa (total dose: 900 mg/m2) and mitoxantrone (MT), administered in a dose-escalation fashion, with ABMT. The dose-limiting non-hematologic toxicity of mitoxantrone was cardiotoxicity, with the maximum tolerated dose being 50 mg/m2 Mucositis and pneumonia were also frequent treatment-related side-effects. The overall tumor response rate was 49% in this heavily pre-treated group of patients. We are currently evaluating the toxicity and efficacy of tandem non-cross-resistant transplant regimens, using the MT combination for the second cycle of therapy, in patients with metastatic breast cancer sensitive to standard dose chemotherapy.

Adult↗
PubMed1992

Relapse and recovery: five to ten year follow-up study of chemically dependent physicians--the Georgia experience.

Of 100 physicians who entered into a continuing care contract during a five-year period with the Impaired Physicians Program of the Medical Association of Georgia, seventy-seven have maintained documentable abstinence from all mood-altering substances. One physician was lost to follow-up. Twenty-two relapsed, eighteen of whom have undergone another treatment for chemical dependence. Only one physician in the relapse group has been involved in a pattern of chronic relapsing behavior.

Adult↗
PubMed1991

Superiority of an antagonist of the luteinizing hormone releasing hormone with emphasis on arginine in position 8, named Argtide.

In the research for more potent antagonists of the luteinizing hormone releasing hormone (LHRH), 13 new peptides with emphasis on arginine in position 8 were designed, synthesized and tested for anti-ovulatory activity (AOA). Two very potent analogs were achieved. N-Ac-D-3-Qal, D-pClPhe, D-3-Pal, Ser, cis-PzACA1a, D-PicLys, Leu, Arg, Pro, D-AlaNH2 showed 63% AOA at 0.125 microgram and 89% at 0.25 microgram, and an ED50 of 30.8 +/- 0.59 and presently may be the most promising antagonist reported. It is named Argtide. N-Ac-D-3-Qal, D-pClPhe, D-3-Pal, Ser, cis-PzACA1a, D-PicLys, Val, Arg, Pro, D-AlaNH2 showed 18% AOA at 0.125 microgram. Arg8 in antagonists may be significant for receptor binding.

Amino Acid Sequence↗