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Biomedical subjects

R White

Publications and source records attributed to R White.

At least 163 records · Page 9Linked to original sources
PubMed1996

Mood, learned resourcefulness and perceptions of control in type 1 diabetes mellitus.

A cohort of 90 insulin-dependent diabetics was examined to explore the relationship between physiological measures of control, learned resourcefulness, and the patients' perceptions of their own and their doctor's control over the diabetes. The doctors' perceptions of control over diabetes were measured. The patient's perceptions of control over diabetes were also measured. The patient's perceptions of control are compared with their doctor's views about medical and patient responsibility for controlling the condition. Patients in this study, overall, have a low level of psychiatric morbidity, with only 7% depressed and with a lower anxiety level than those reported in other published studies. It was found that patients who view control of good outcomes to be in the hands of their doctors fare worse as far as physiological control is concerned. There was little congruence between the attitudes of doctor and patient pairs about responsibility for controlling the diabetes mellitus. The most important clinical implication of the study is that there appears to be a relationship between poor physiological control and a passive, dependent approach to the condition.

Adolescent↗
PubMed1996

A computer model of major haemorrhage and resuscitation.

An interactive computer model is described which uses 'blood volume deficit' and 'bleeding duration' together with rates of infusion to simulate the first two hours of haemorrhage. It allows multiple infusions of various fluids to be specified and includes an estimation of the volumes added by the transcapillary refill mechanism. The output is expressed graphically in terms of blood pressure and haematocrit at intervals of one minute. This computer model has proved useful for assessing the effects of a range of variables in hypovolaemic shock. It has considerable potential for investigating the relative efficacy of various clinical protocols and could provide an alternative to animal experimentation which has so far been the primary method of obtaining data on acute haemorrhage. It is also a useful teaching aid.

Animals↗
PubMed1996

An updated basal body temperature method.

Basal body temperature (BBT) readings are handicapped as fertility predictors by exogenous influences on women's temperatures, many of which could be adjusted for by the presence of a non-cycling control. We, a married, cohabiting couple, tracked our BBTs for two months. We found substantial temperature covariability. When there were difficult-to-explain changes in the female partner's temperature, similar changes in the male partner's temperature suggested that these fluctuations were not attributable to ovulation. Additionally, a clear mid-cycle widening of our temperature gap suggested that ovulation had occurred. This is a limited trial of a new method. However, the potential for substantially improving the accuracy and usefulness of a globally utilized method, coupled with its inexpensiveness, ease, and painlessness, call for a larger study.

Adult↗
PubMed1996

Aromatase activity and CYP19 gene expression in breast cancers.

The aromatase enzyme complex is responsible for the conversion of C19 androgens to oestrogens. Aromatase expression in oestrogen-responsive breast cancers may be an important mechanism of autocrine regulation in tumour growth. To evaluate whether aromatase cytochrome P450 (P450arom) transcript levels within breast tumours were correlated to the enzyme activity, a specific competitive reverse transcription-polymerase chain reaction (RT-PCR) was developed. In this reaction, a 32 base-deleted complementary RNA was used as internal standard. In vitro aromatase activity was measured by either the tritium release assay or characterization of oestrogen fractions. Results indicate that there is a positive correlation between P450arom transcript levels and enzyme activity, but the relationship does not reach statistical significance. Therefore, whereas aromatase mRNA quantification may be an option by which to monitor the potential of tumour to synthesize oestrogens, it will not accurately reflect enzyme activity in a minority of tumours. Preliminary evidence was obtained in a tumour with low enzyme activity and a high P450arom transcript level for the presence of an endogenous aromatase inhibitor. This study highlights the necessity to characterize factors involved in the regulation of aromatase activity in such tumours.

Aromatase↗
PubMed1996

A professional practice model: two key components.

Professional practice models provide decentralized approaches to nursing practice. The components of such a model should include a primary nursing delivery system, decentralized decision making, salary compensation, self-scheduling and quality circles. This article describes two of the key components of the model--salaried compensation and self-scheduling--on a unit in one agency.

Decision Making, Organizational↗
PubMed1996

Intravenous regional anesthesia for management of children's extremity fractures in the emergency department.

OBJECTIVE: To determine if intravenous regional anesthesia (Bier block) is safe and efficacious for the management of children's extremity fractures in the emergency department (ED). DESIGN: Retrospective review of 470 ED records of children presenting with extremity fractures reduced with intravenous regional anesthesia from 1989 through 1994. SETTING: ED of a 256-bed teriary care children's hospital. PATIENTS: Four hundred seventy children treated in the ED from 1989 through 1994 for extremity fractures reduced with Bier block anesthesia. Three hundred eleven boys and 159 girls with a mean age of 9.4 years (range two-19 years) were included in the review. INTERVENTION: Utilization of intravenous regional anesthesia for fracture reduction of affected extremity. MAIN OUTCOME MEASURES: ED records and orthopaedic consultation notes were reviewed for adequacy of reduction, number of reduction attempts, efficacy of anesthesia, and any associated untoward effects or complications, and review of operative notes of any children who required a subsequent procedure in the operating room (OR) under general anesthesia. RESULTS: Ninety-nine percent (467) had adequate anesthesia for fracture reduction. There were no complications noted. Specifically, there were no incidents of hypotension, tachycardia, seizures, or arrhythmia. Bier block anesthesia was aborted in three patients because venous access could not be obtained in the affected extremity. Less than 2% (8) required a general anesthetic in the OR for further treatment. All of the children taken to the OR underwent internal fixation of the fracture. CONCLUSIONS: Intravenous regional anesthesia (Bier block) is safe and efficacious in the treatment of children's extremity fractures in the ED.

Adolescent↗
PubMed1996

Gynandroblastoma of ovary with juvenile granulosa cell component and heterologous intestinal type glands.

An ovarian gynandroblastoma in a 15-year-old girl is described. The predominant component was juvenile granulosa cell tumour. Areas of adult granulosa cell tumour and Sertoli cell elements were also present. Stromal theca and luteinised cells were identified. An additional histological finding was the presence of heterologous intestinal type glands. There was positive immunohistochemical staining of juvenile and adult granulosa cell areas with inhibin and MIC2 antibodies. Electronmicroscopy showed a close ultrastructural resemblance between tumour cells in granulosa and Sertoli cell areas, in spite of differences in architectural pattern, suggesting that both morphological components may derive from a single cell of origin. The tumour demonstrates a unique combination of elements which has not previously been described.

Adolescent↗
PubMed1996

Comparative in vitro pharmacodynamics of imipenem and meropenem against Pseudomonas aeruginosa.

MICs are commonly used to assess the in vitro activities of antimicrobial agents; however, they provide minimal information on the pattern of bacterial activities. Time-kill studies with extensive sampling allow assessment of both the rate and extent of bacterial killing and regrowth. We compared imipenem and meropenem by both MIC-MBC testing and a time-kill study with P. aeruginosa 27853. In the time-kill study, concentration/MIC ratios ranging from 0.0625 to 32 times the MIC were studied. The kill rate, time to 99.9% kill, doubling time of regrowth, and area under the bacterial killing curve (AUKC) were evaluated. Degradation during the testing procedure was accounted for by assessing actual drug exposure as determined by the area under the concentration-time curve. Pharmacodynamic parameters were compared by using the Wilcoxon signed-rank test. The modal MIC and MBC for imipenem were 2 and 4 micrograms/ml, respectively, and those for meropenem were 0.25 and 0.5 microgram/ml, respectively. In the time-kill study, both agents displayed concentration-dependent activity over a range of 0.25 to 4 times the MIC. Initial killing (0 to 1 h) was faster with imipenem at the same concentration/MIC ratios (P = 0.0506). The time to 99.9% kill was approximately 5 h for both agents. When regrowth occurred, the doubling rate for imipenem, which was the same as that for the growth control, was twice as rapid as that for meropenem. At the same concentrations, the AUKCs over 24 h were lower for meropenem than for imipenem (P = 0.0280); however, when normalized by MIC, imipenem resulted in smaller AUKCs. Comparison of plots of area under the concentration-time curve versus AUKC, which accounted for drug degradation and actual drug exposure, revealed that meropenem was three times more active than imipenem, rather than the eightfold difference suggested by MICs. Time-kill curves with extensive sampling and measurement of actual drug exposure, rather than traditional MIC testing, may more accurately assess differences in the in vitro activities of antimicrobial agents.

Cell Division↗
PubMed1996

An enhanced-sensitivity branched-DNA assay for quantification of human immunodeficiency virus type 1 RNA in plasma.

The quantification of human immunodeficiency virus type 1 (HIV-1) RNA has facilitated clinical research and expedited the development of antiretroviral drugs. The branched-DNA (bDNA) assay provides a reliable method for the quantification of HIV-1 RNA in human plasma and is considered one of the most reproducible assays ready for use in clinical trials. A series of oligonucleotide probe design and solution changes have been developed to enhance the sensitivity of the bDNA assay while maintaining its performance characteristics. Among the changes incorporated into the enhanced-sensitivity bDNA (ES bDNA) assay to reduce the background level and enhance the signal are the use of shorter overhang sequences of target probes for capture, the cruciform design of target probes for amplification, and the addition of preamplifier molecules. The ES bDNA assay is at least 20-fold more sensitive than the first-generation bDNA assay, yet it maintains a high level of accuracy, linearity, and reproducibility. Further, quantification values obtained with the ES bDNA assay and the first-generation bDNA assay are highly correlated, thus allowing for meaningful comparisons of HIV-1 RNA levels in specimens tested with either assay. The ES bDNA assay may be useful in determining the prognostic value of HIV-1 RNA levels of below 10,000 copies per ml and in assessing the clinical benefit of antiretroviral therapy-induced decreases in plasma HIV-1 RNA sustained at levels of below 10,000 copies per ml.

Anti-HIV Agents↗
PubMed1996

Randomized trial of vinorelbine compared with fluorouracil plus leucovorin in patients with stage IV non-small-cell lung cancer.

PURPOSE: This prospective randomized trial was performed to compare the effectiveness of intravenous vinorelbine tartrate with intravenous fluorouracil and leucovorin (5-FU/LV) on the primary end points of survival, quality of life (QOL), and relief of cancer-related symptoms in patients with advanced non-small-cell lung cancer (NSCLC). Secondary end points included tumor response rates and time to treatment failure. In addition, the safety of both treatment regimens was evaluated in this multicenter study. PATIENTS AND METHODS: Two hundred sixteen patients with stage IV NSCLC were enrolled onto this study from 18 centers. Vinorelbine was administered at a dose of 30 mg/m2/wk. 5-FU/LV was administered at a dose of 425 mg/m2 and 20 mg/m2, respectively, for 5 consecutive days every 4 weeks. Patients with progressive disease or toxicity were removed from study while responding and stable patients were continued on therapy. RESULTS: The median survival time of patients who received vinorelbine was 30 weeks, with 25% of patients alive at 1 year, compared with a median survival time of 22 weeks and 16% of patients alive at 1 year for those treated with 5-FU/LV (P = .03, log-rank test). This improvement in survival was associated with a higher objective response rate (12% v 3%) and time to treatment failure (10 weeks v 8 weeks) for vinorelbine versus 5-FU/LV. The dose-limiting toxicity of vinorelbine was granulocytopenia, with 54% of patients experiencing grade 3/4 granulocytopenia. Nonhematologic toxicity of vinorelbine was generally grade 1 or 2. The most common grade 3 toxicities were related to injection-site reactions. CONCLUSION: This trial confirms the efficacy of vinorelbine in patients with advanced NSCLC. The clinical activity and relatively favorable toxicity profile of this agent make it a reasonable and useful treatment option in the management of patients with this disease.

Adult↗
PubMed1996

Abdominal aortic aneurysm screening in elderly males with atherosclerosis: the value of physical exam.

The purpose was 1) To assess the prevalence of abdominal aortic aneurysms (AAA) in elderly males with atherosclerosis and 2) to evaluate the value of physical exam (PE) by a vascular surgeon in detecting AAA. A total of ninety-six males older than 55 years referred to vascular surgery clinic with atherosclerotic disease were screened prospectively with PE by a vascular surgeon, followed by ultrasonography (US). Atherosclerosis was documented by ankle brachial index and duplex US. Patients who had recently undergone a vascular procedure, aortography, laparotomy, abdominal computed tomography, or US were excluded. Mean age was 67 years. Patients were 67 per cent Caucasian, 32 per cent black, and 1 per cent Hispanic. Presenting complaints were related to claudication (83%), carotid disease (19%), both (3%), and subclavian stenosis (1%). Patient characteristics included cigarette smoking (85%), hypertension (67%), cardiac disease (51%), diabetes (45%), stroke (18%), and chronic obstructive pulmonary disease (8%). One (1%) 3.7 cm AAA was detected by US. Sensitivity of PE was 100 per cent and specificity 92 per cent. Twenty-two (23%) patients were too obese for us to feel the aortic pulse. Screening cost was $14,250. The prevalence of AAA in this population is very low. AAA screening should be reserved for patients with a positive PE or who are too obese for the examiner to feel the aortic pulse.

Aged↗
PubMed1996

Peritoneal dialysis solution attenuates microvascular leukocyte adhesion induced by nitric oxide synthesis inhibition.

In the mesenteric microcirculation, inhibition of nitric oxide (NO) synthesis results in an inflammatory response through increased leukocyte adherence to the microvascular postcapillary venular endothelium. Recent studies have demonstrated that elevated concentrations of endogenous NO synthesis inhibitors are present in renal failure. How peritoneal dialysis solutions may affect leukocyte-endothelial interactions during inflammation induced by NO synthesis inhibition has been previously unknown. Using in vivo intravital microscopy of the rat mesenteric postcapillary venules, microvascular leukocyte adherence was quantitated during baseline conditions in which the mesentery was superfused with a buffer solution, followed by the superfusion of a NO synthesis inhibitor NG-nitro-L-ARGININE methyl ester (L-NAME) added to the buffer, followed by 4.25% Dianeal (4.25% D). When compared to baseline, L-NAME increased the mean number of adherent leukocytes by fivefold (2.2 +/- 0.9 vs 11.6 +/- 3.6 leukocytes/100 microns venule/10 min, p < 0.05), while 4.25% D quickly reversed the L-NAME-induced inflammatory response, returning the number of adherent leukocytes back to baseline values (11.6 +/- 3.6 vs 2.4 +/- 1.3 leukocytes/100 microns venule/ 10 min, p < 0.05). These results confirm that NO synthesis inhibition induces inflammation in mesenteric postcapillary venules. Superfusion of 4.25% D reverses leukocyte adhesion induced by NO synthesis inhibition. Thus, a standard peritoneal dialysis solution (4.25% D) reverses the leukocyte-adhesive effects of NO synthesis inhibition in the mesenteric microcirculation.

Animals↗
PubMed1996

Healthy Hearts at work: Prince Edward Island Heart Health Program CSC worksite pilot project.

Prince Edward Island experiences a higher-than-average death rate from cardiovascular disease. The Prince Edward Island Heart Health Program is a health promotion/disease prevention research project of Health Canada and the Prince Edward Island Department of Health and Social Services. This paper describes and evaluates a worksite program, based on the principles of community mobilization, that was initiated with the Civil Service Commission of the Prince Edward Island government. The building of a partnership, the risk appraisal session administered in the workplace, the establishment of an Employee Wellness Committee, and subsequent programming which has occurred in the workplace were the key components in the process. Collaboration with the partner agency and participation of employees in the planning process has resulted in the delivery of programs which could not have been achieved by one of the agencies alone, without many additional resources. It is hoped that these characteristics of collaboration and employee participation will also result in sustainability of this initiative when PEI Heart Health is no longer involved.

Cardiovascular Diseases↗
PubMed1996

The Dentists' Well-Being Committee of Maryland.

The Maryland Dentist's Well-Being Committee was formed in 1980 as a standing committee of the Maryland State Dental Association. The committee has assisted many dentists over the years with problems such as stress, alcoholism, drug dependence, psychiatric disorders, medical problems, HIV (human immunodeficiency virus) disease, neurological disorders, and other illnesses that cause impairment. Key elements of the committee include confidentiality, a good working relationship with the Maryland State Board of Dental Examiners, advocacy efforts, and a paid clinical coordinator with special expertise in mental health and addiction treatment.

Confidentiality↗
PubMed1996

The advantages of the disease model.

Health care professionals are interested in practical definitions that provide solutions to problems. There are many advantages to defining chemical dependence as a disease. This paper gives a health care professional clear directions regarding identifying the problem of chemical dependence and specifying a specific treatment plan for patients. We review the issues of personal responsibility, the moral model of addictions, and the neuropharmacology of the disease process, and advocate for the disease model as an effective, practical method for treating alcoholism and drug dependence.

Attitude of Health Personnel↗