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Biomedical subjects

G C Williams

Publications and source records attributed to G C Williams.

At least 37 records · Page 2Linked to original sources
PubMed1998

Autonomous regulation and long-term medication adherence in adult outpatients.

Self-determination theory was applied to explore the motivational basis of adherence to long-term medication prescriptions. Adult outpatients with various diagnoses who had been on a medication for at least 1 month and expected to continue (a) completed questionnaires that assessed their autonomous regulation, other motivation variables, and perceptions of their physicians' support of their autonomy by hearing their concerns and offering choice; (b) provided subjective ratings of their adherence and a 2-day retrospective pill count during an interview with a clinical psychologist; and (c) provided a 14-day prospective pill count during a subsequent, brief telephone survey. LISREL analyses supported the self-determination model for adherence by confirming that patients' autonomous motivation for adherence did mediate the relation between patients' perceptions of their physicians' autonomy support and their own medication adherence.

Adult↗
PubMed1998

Supporting autonomy to motivate patients with diabetes for glucose control.

OBJECTIVE: We applied the self-determination theory of human motivation to examine whether patient perceptions of autonomy supportiveness (i.e., patient centeredness) from their diabetes care providers related to improved glucose control over a 12-month period. RESEARCH DESIGN AND METHODS: We conducted a prospective cohort study of patients with diabetes from a diabetes treatment center at a university-affiliated community hospital. Participants were 128 patients between 18 and 80 years of age who took medication for diabetes, had no other major medical illnesses, and were responsible for monitoring their glucose and taking their medications. The main outcome measure was a change in HbA1c values over the 12 months of the study RESULTS: Patient perception of autonomy support from a health care provider related to a change in HbA1c values at 12 months (P < 0.05). Further analyses showed that perceived autonomy support from the staff related to significant increases in patient autonomous motivation at 12 months (P < 0.05); that increases in autonomous motivation related to significant increases in perceived competence (P < 0.05); and that increases in a patient's perceived competence related to significant reductions in their HbA1c values over 12 months (P < 0.001). CONCLUSIONS: The findings support the prediction of the self-determination theory that patients with diabetes whose health care providers are autonomy supportive will become more motivated to regulate their glucose levels, feel more able to regulate their glucose, and show improvements in their HbA1c values.

Adolescent↗
PubMed1997

Motivation underlying career choice for internal medicine and surgery.

Self-determination theory (Deci and Ryan, 1985) was used to predict medical students' career choices for internal medicine or surgery based on their experiences of the autonomy support provided by the instructors in the two corresponding third-year clerkships. Fourth-year medical students (n = 210) at three medical schools completed questionnaires that assessed (1) retrospective prior likelihood (as of the end of second year) of their going into internal medicine and surgery, (2) their perceived competence with respect to these two medical specialties, (3) their interest in the problems treated in each specialty, (4) the autonomy support of the instructors on the two corresponding rotations, (5) the current likelihood (late in the fourth year) of going into each of the two specialties, and (6) their actual residency choices. For a subset (n = 64), actual prior likelihoods of going into the two careers had also been assessed at the end of their second year. Structural equation modeling confirmed, as hypothesized, (a) that perceived autonomy support of the corresponding clerkship would predict students' choices of internal medicine or surgery, even after the effects of retrospective (and actual) prior likelihood had been removed, and (b) that this relationship between perceived autonomy support and career choice was mediated by perceived competence and interest. The present study suggests that students' experiences on clerkships do affect the likelihood that they will select particular specialties, and that students' interest in the areas are good indicators of the selections they will make.

Adult↗
PubMed1996

Motivational predictors of weight loss and weight-loss maintenance.

Self-determination theory proposes that behavior change will occur and persist if it is autonomously motivated. Autonomous motivation for a behavior is theorized to be a function both of individual differences in the autonomy orientation from the General Causality Orientations Scale and of the degree of autonomy supportiveness of relevant social contexts. We tested the theory with 128 patients in a 6-month, very-low-calorie weight-loss program with a 23-month follow-up. Analyses confirmed the predictions that (a) participants whose motivation for weight loss was more autonomous would attend the program more regularly, lose more weight during the program, and evidence greater maintained weight loss at follow-up, and (b) participants' autonomous motivation for weight loss would be predicted both by their autonomy orientation and by the perceived autonomy supportiveness of the interpersonal climate created by the health-care staff.

Adult↗
PubMed1996

Internalization of biopsychosocial values by medical students: a test of self-determination theory.

Two studies tested self-determination theory with 2nd-year medical students in an interviewing course. Study 1 revealed that (a) individuals with a more autonomous orientation on the General Causality Orientation Scale had higher psychosocial beliefs at the beginning of the course and reported more autonomous reasons for participating in the course, and (b) students who perceived their instructors as more autonomy-supportive became more autonomous in their learning during the 6-month course. Study 2, a 30-month longitudinal study, revealed that students who perceived their instructors as more autonomy-supportive became more autonomous in their learning, which in turn accounted for a significant increase in both perceived competence and psychosocial beliefs over the 20-week period of the course, more autonomy support when interviewing a simulated patient 6 months later, and stronger psychosocial beliefs 2 years later.

Adult↗
PubMed1994

Medical students' motivation for internal medicine.

OBJECTIVE: To verify that motivational concepts tested in other educational settings are relevant to understanding medical students' choice of a career in internal medicine. More specifically, to compare the effects of "facilitating students' interest" versus "controlling students' learning" as educational models during the internal medicine clerkship. DESIGN: An observational retrospective study of 89 fourth-year medical students. Structural equation modeling compared the two models statistically. MAIN OUTCOME MEASURE: Student choice of internal medicine residency. RESULTS: Instructors who supported students' autonomy engendered in students greater feelings of competence and interest in internal medicine than did controlling instructors. Perceived competence further enhanced students' interest in internal medicine. In turn, interest predicted students' choosing an internal medicine residency. Overall, the facilitating students' interest model better explained students' choice of internal medicine than did the controlling students' learning model. CONCLUSIONS: The results verify that the nature of the learning climate during the internal medicine clerkship is an important predictor of students' subsequent pursuit of internal medicine training. Instructors who teach in an autonomy-supportive manner enhance students' perceived competence and interest in internal medicine, which increases the likelihood they will select an internal medicine residency.

Career Choice↗
PubMed1991

"The facts concerning the recent carnival of smoking in Connecticut" and elsewhere.

The behavior of health care practitioners toward their patients can greatly affect the patients' motivation for change. Mark Twain's story, "The Facts Concerning the Recent Carnival of Crime in Connecticut," is used to illustrate how traditional strategies for motivating patients to change can have the paradoxic effect of inhibiting change and growth. We use a theory of human motivation, referred to as self-determination theory, to explain this effect and suggest alternative strategies for facilitating patient motivation. Empirical tests of the theory have shown that people will accept more responsibility for behavior change when motivated internally rather than externally. In the doctor-patient relationship, this internal motivation for change can be facilitated when doctors allow choice, provide relevant information, and acknowledge the patient's perspective. We propose a simple, three-question model, consistent with self-determination theory, for physicians to use with patients who smoke and are not yet ready to try quitting.

Counseling↗
PubMed1991

The dawn of Darwinian medicine.

While evolution by natural selection has long been a foundation for biomedical science, it has recently gained new power to explain many aspects of disease. This progress results largely from the disciplined application of what has been called the adaptations program. We show that this increasingly significant research paradigm can predict otherwise unsuspected facets of human biology, and that it provides new insights into the causes of medical disorders, such as those discussed below: 1. Infection. Signs and symptoms of the host-parasite contest can be categorized according to whether they represent adaptations or costs for host or parasite. Some host adaptations may have contributed to fitness in the Stone Age but are obsolete today. Others, such as fever and iron sequestration, have been incorrectly considered harmful. Pathogens, with their large populations and many generations in a single host, can evolve very rapidly. Acquisition of resistance to antibiotics is one example. Another is the recently demonstrated tendency to change virulence levels in predictable ways in response to changed conditions imposed incidentally by human activities. 2. Injuries and toxins. Mechanical injuries or stressful wear and tear are conceptually simpler than infectious diseases because they are not contests between conflicting interests. Plant-herbivore contests may often underlie chemical injury from the defensive secondary compounds of plant tissues. Nausea in pregnancy, and allergy, may be adaptations against such toxins. 3. Genetic factors. Common genetic diseases often result from genes maintained by other beneficial effects in historically normal environments. The diseases of aging are especially likely to be associated with early benefits. 4. Abnormal environments. Human biology is designed for Stone Age conditions. Modern environments may cause many diseases-for example, deficiency syndromes such as scurvy and rickets, the effects of excess consumption of normally scarce nutrients such as fat and salt, developmental diseases such as myopia, and psychological reactions to novel environments. The substantial benefits of evolutionary studies of disease will be realized only if they become central to medical curricula, an advance that may at first require the establishment of one or more research centers dedicated to the further development of Darwinian medicine.

Adaptation, Physiological↗
PubMed1989

Health maintenance issues of the elderly. Oral health.

The risk for the most serious oral disease, oral cancer, increases with age as does the prevalence of other oral soft tissue diseases. Tooth loss is not part of normal aging. As more elderly retain their natural dentition, they are at continued risk for tooth-related diseases such as caries and periodontal disease. Preventive dental programs, including an oral exam as part of the physical examination, will be indicated for adults.

Aged↗
PubMed1980

Stereochemistry of the side chain oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol in man.

Previous in vitro studies have shown that the oxidation of the side chain of bile acid precursors can start with either microsomal or mitochondrial enzyme systems. The microsomal system oxidizes the terminal methyl group (C-26) of the side chain that originates from C-2 of mevalonic acid, and the mitochondrial system oxidizes the terminal methyl group (C-27) derived from C'-3 of mevalonic acid. We administered [2-14C]-mevalonic acid to a patient with a complete bile fistula and isolated from the bile 3 alpha,7 alpha,12 alpha-trihydroxy[1,7,15,22,26-14C]5 beta-cholestanoic acid, a precursor in the synthesis of cholic acid which has undergone partial oxidation of the side chain. This compound was chemically decarboxylated and the liberated CO2 was trapped and counted. The recovery from control experiments using [24-14C]cholic acid was 82.6 +/- 2.3% (+/- 1 S.D.). However, following decarboxylation of 3 alpha,7 alpha,12 alpha-trihydroxy[14C5]5 beta-cholestanoic acid, only 7.5 +/- 0.58% (+/- S.D.) of the C-26 radioactivity was recovered. This study suggests that the major pathway of side chain oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha-triol starts with hydroxylation of the methyl group derived from C'-3 of mevalonate (C-27) by mitochondrial enzymes. It is also concluded that the 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-27-oic acid formed in man has the R configuration at carbon 25.

Bile↗
PubMed1980

Competitive inhibition of side chain oxidation of 3 alpha, 7 alpha-dihydroxy-5 beta-cholestan-26-oic acid by 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestan-26-oic acid in the hamster.

3 alpha,7 alpha-dihydroxy-5 beta-cholestan-26-oic acid (DHCA) and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid (THCA) are metabolized into chenodeoxycholic acid and cholic acid, respectively, through oxidation and cleavage of the terminal three carbons of the side chain. The present study was designed to determine if the same or different side chain oxidation systems are used by these compounds in the bile fistula hamster model. Although a single injection of [3H]THCA is nearly completely metabolized into cholic acid, only about 50% is converted into cholic acid when THCA is infused at a rate of 0.083 mumol/min. The remainder is excreted in the bile unchanged indicating saturation of the side chain oxidation system. Fifty-nine +/- 1.1% (+/- 1SEM) of a single injection of [3H]DHCA is metabolized into chenodeoxycholic acid in bile fistula hamsters infused with either saline or cholic acid at a rate of 0.083 mumol/min. The remainder was excreted as several other metabolic products including cholic acid. However, when [3H]DHCA was administered during an 0.083 mumol/min infusion of THCA, only 39.0 +/- 4.5% of the radioactivity in bile was identified as chenodeoxycholic acid. Thus, this study indicates that DHCA and THCA share at least one of the enzymes involved in side chain oxidation.

Animals↗