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Biomedical subjects

R Wheeler

Publications and source records attributed to R Wheeler.

At least 73 records · Page 4Linked to original sources
PubMed1982

Development and evaluation of an inhibitor-releasing matrix for intrauterine devices.

Antifibrinolytic agents when released into the uterine cavity decrease menorrhagia associated with IUD use. Our objective was to develop a matrix that could be incorporated onto an IUD and release anti-fibrinolytic agents. The copolymer ethylene-vinyl acetate (EVA) was selected for detailed study because it has the advantage over other materials in that it can release large molecular weight substances for more than 100 days, and allows incorporation of large amounts of anti-fibrinolytic agents with different molecular weights. Two compounds, tranexamic acid (AMCA, MW=157) and Trasylol (Kunitz pancreatic trypsin inhibitor, (MW=6,500) were incorporated into the EVA matrix and their release rates measured. In vitro studies with AMCA showed that after the initial burst, a constant high release rate was obtained over a prolonged period of time. The in utero release rate of AMCA from the EVA matrix in rabbits was similar to that obtained in vitro. By contrast, the release rate of Trasylol decreased to low levels during incubation in vitro. The release rate of Trasylol in utero however, appeared to be higher than that in vitro.

Animals↗
PubMed1982

Flagellar preparations from Pseudomonas aeruginosa: animal protection studies.

Recent reports have suggested that motility is associated with virulence in Pseudomonas aeruginosa. We have confirmed this observation by showing that groups of mice immunized with P. aeruginosa flagellar-antigen preparations display enhanced survival when they are subsequently burned and challenged locally in the burned area with strains of P. aeruginosa. The protection appears to be due to the immobilization of the microorganisms in the burned skin tissue. Liver elongation factor 2 is also protected. The protection afforded by immunization with flagellar-antigen preparations is independent of the somatic antigenic type of the challenging strain but is flagellar-antigen specific. These data suggest that vaccination with flagellar-antigen preparations may provide a viable prophylactic or therapeutic alternative to antibiotic therapy for use in compromised patient population in which P. aeruginosa poses a serious infection threat.

Animals↗
PubMed1981

Tarsal coalitions: review of the literature and case report of bilateral dual calcaneonavicular and talocalcaneal coalitions.

Inasmuch as midfoot coalitions do not occur frequently, a preadolescent or early adolescent patient who has persistent complaints of painful flat foot with peroneal or anterior tibial muscle spasm warrants special evaluation. The patient may complain of becoming easily tired or report the onset of pain with increased activity. Clinical examination may reveal local tenderness over the area of the coalition, but this is not a consistent finding. Restricted inversion of the foot with spasm of the peroneals, forefoot abduction or pronation should alert the examining physician that a tarsal coalition may be present. Appropriate roentgenograms examining all of the possibly involved joints should be obtained. These include 45 degrees oblique views of the foot, which usually give a satisfactory view of the calcaneonavicular joint. Coalitions may occur in any of the facets of the talocalcaneal joint and therefore all facets must be evaluated. The anatomic location of the facets can be variable and multiple-angle axial views may be required. We recommend a 45 degrees axial view to visualize the posterior and middle facets, since they are normally parallel in the axial view. If fibrous coalitions are present, the middle facet may be oblique. Tomography is necessary to visualize the anterior facet or to confirm a coalition either in the middle or in the posterior facets.

Adolescent↗
PubMed1978

N-Butyl methacrylate and paraffin as an embedding medium for light microscopy.

A method of tissue embedding using n-butyl methacrylate and paraffin is described. Following alcohol dehydration and infiltration with the methacrylate monomer, tissues are embedded in gelatin capsules in a mixture consisting of 3.5 g of paraffin for each 10 ml of methacrylate. Benzoyl peroxide (0.2 g for each 10 ml of monomer) is added as the catalyst and the methacrylate polymerized in a 50 C oven for 18--24 h. Following polymerization the block is trimmed and embedded in paraffin to provide a firm support during sectioning. A water trough attached to the microtome knife is essential to facilitate the handling of sections and ribbons. For serial sections a mixture of equal weights of beeswax and paraffin is used to make the sections adhere to each other. Usual staining procedures can be used since the embedding medium is readily soluble in xylene.

Acrylates↗
PubMed1975

Hydroxylation of testosterone at carbons 1, 2, 6, 7, 15 and 16 by the hepatic microsomal fraction from adult female C57BL/6J mice.

The metabolism of a mixture of [4-14C]- and [7 beta-2H]testosterone by the hepatic microsomal fraction from adult femal C57BL/6J mice has been investigated. The following metabolites were identified by their mass spectra and by their retention times on gas chromatography on one or two phases: 1epsilon-, 2beta-, 6alpha-, 6beta-, 7alpha-, 15alpha-, 15beta-, 16alpha- and 16beta-hydroxytestosterone; 6alpha-, 6beta- and 7alpha-hydroxy-4-androstene-3,17-dione; and 4-androstene-3,17-dione. A compound tentatively identified as 6- or 7-oxotestosterone was also isolated. 17beta-Hydroxy-4,6-androstadien-3-one, 17beta-hydroxy-1,4-androstadien-3-one and 4,6-androstadiene-3,17-dione were identified but are considered to arise non-enzymatically from 7alpha-hydroxytestosterone, 1epsilon-hydroxytestosterone and 7alpha-hydroxy-4-androstene-3,17-dione, respectively.

Acclimatization↗
PubMedDate not supplied

Intraarterial chemotherapy for head and neck cancer, Part 1: Theoretical considerations and drug delivery systems.

The principal objective of regional chemotherapy is tumor cell kill. The rationale for regional delivery is based on the steep dose/response curve exhibited by most antineoplastic agents. Intraarterial (IA) chemotherapy has the potential advantage of increased drug concentration at the tumor site, decreased systemic drug levels, and continuous tumor cell exposure to an antineoplastic agent. Despite these advantages, the use of IA chemotherapy has not been universally accepted. This is in part due to the difficulties associated with establishing and maintaining arterial access. Considerable improvement in the techniques and efficacy of regional therapy for head and neck cancer will be necessary before there is widespread clinical acceptance. These improvements must be based on anatomic and pharmacologic factors that ensure success of regional therapy. In addition, the development of safe, reliable delivery systems will be necessary. Part 1 of this two-part article will review these factors and discuss delivery systems.

Antineoplastic Agents↗
PubMedDate not supplied

Intraarterial chemotherapy for head and neck cancer, Part 2: Clinical experience.

Despite almost 3 decades of experience, the use of intraarterial (IA) chemotherapy for the treatment of head and neck cancer is not universally accepted. The overall reported response rates are not substantially different from the therapeutic results obtained with systemic therapy. The additional complications associated with establishing and maintaining arterial access have further dampened enthusiasm for this approach. It is clear that considerable improvement in the techniques and efficacy of IA chemotherapy is necessary. This second and last part of this article considers the past and present clinical experience with IA therapy in the treatment of head and neck cancer and explores future developments.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Comparison of NIOSH 5040 method versus Aethalometer to monitor diesel particulate in school buses and at work sites.

This study, undertaken initially to understand apparent differences between two recent reports of diesel particulate matter (DPM) inside school buses, involved side-by-side comparisons of two different methods for measuring ambient and occupational exposures to DPM. The NIOSH 5040 method yields time-weighted-average measurements of elemental carbon (EC) and organic carbon (OC), whereas the Aethalometer yields near-real time measures of carbonaceous particles (black carbon or BC) by optical absorption. The two methods were compared on three school buses and in three different work sites. Three side-by-side sampling configurations were used (open-faced filter with and without two different cyclones) in triplicate along with two or three Aethalometers. BC readings were correlated with results from open-faced cassettes, but there were statistically significant differences between the results of side-by-side Aethalometers. In addition, Aethalometer airflow rates were inaccurate, the instruments were sensitive to vibration, optical calibration could not be performed, and historically derived conversion factors to relate EC and BC were not appropriate. The Aethalometer could prove useful for monitoring of industrial work sites, but only after a method for external calibration and improvements in pump design and vibration isolation are developed.

Carbon↗
PubMedDate not supplied

Modeling the effects of light, carbon dioxide, and temperature on the growth of potato.

This study examined the effects of light, temperature and carbon dioxide on the growth of potato (Solanum tuberosum L.) in a controlled environment in order to ascertain the best growing conditions for potato in life support systems in space. 'Norland' and 'Russet Burbank' were grown in 6-L pots of peat-vermiculite for 56 d in growth chambers at the University of Wisconsin Biotron. Environmental factor levels included continuous light (24-h photoperiod) at 250, 400, and 550 micromoles m-2 s-1 PPF; constant temperature at 16, 20, and 24 degrees C; and CO2 at approximately 400, 1000, and 1600 microliters L-1. Separate effects analysis and ridge analysis provided a means to examine the effects of individual environmental factors and to determine combinations of factors that are expected to give the best increases in yields over the central design point. The response surface of Norland indicated that tuber yields were highest with moderately low temperature (18.7 degrees C), low CO2 (400 microliters L-1) and high light (550 micromoles m-2 s-1 PPF). These conditions also favored shorter stem growth. Russet Burbank tuber yields were highest at moderately low temperature (17.5 degrees C), high CO2 (1600 microliters L-1) and medium analyses will be used to project the most efficient conditions for growth of potatoes in closed ecological life support systems (CELSS) in space colonies.

Carbon Dioxide↗
PubMedDate not supplied

Part-time doctors: reduced working hours for primary care physicians.

Women are entering the professional workforce in increasing numbers, and male professionals are more likely than ever to be involved in dual-career families. For primary care physicians the traditional 50-70-hour work week increasingly creates conflict between professional and other personal goals. Many believe that unless physicians work these long hours they will be unable to successfully provide personal, high-quality continuing care to their patients. Long-term career development for physicians who choose nontraditional arrangements has also presented problems. The authors review the literature on part-time work for physicians, then discuss their experiences as part-time family physicians at an academic health center. Various specific strategies are recommended for physicians and institutions considering part-time employment.

Adult↗
PubMedDate not supplied

Doctors having families: the effect of pregnancy and childbearing on relationships with patients.

Family physicians care for patients in all stages of the life-cycle, while at the same time proceeding themselves through the course of adult development. The purpose of this study was to examine, from the doctor's point of view, changes in the doctor-patient relationship resulting from the physician's pregnancy and child-bearing. Five faculty family physicians participated via individual interviews and group discussion. Two women without children, the clinical psychologist interviewer, and other faculty family physicians joined in the review of the interviews and the group discussion. Comprehensibility, reciprocity, mutuality, identification, credibility, availability for long-term relationships, nurturing, and support emerged as themes in the evolution of relationships with patients. The process of examining the effect of childbearing on our relationships with patients unexpectedly revealed how the dual expectation of career and motherhood causes colleagues without children to feel inadequate. On the other hand, the study itself had the positive effect of facilitating the resolution of long-standing tensions among group members. We conclude that becoming mothers, a significant life change, had a transforming effect on our clinical work with patients and that studying this effect as a group fostered growth in the relationships among the participants.

Adult↗