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Biomedical subjects

A Boyce

Publications and source records attributed to A Boyce.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of selected physicochemical characteristics of commercial phytases relevant to their application in phosphate pollution abatement.

The enzyme phytase catalyses the dephosphorylation of phytic acid and it's salts, phytates. Supplementation of monogastric animal feed with microbial-derived phytase increases the bioavailability of phytic acid bound phosphate. This facilitates a reduction in the addition of inorganic phosphate to the feed and reduces phosphorus excretion. To achieve maximum efficacy in terms of phosphate pollution abatement, supplemental phytases added to animal feed must survive thermal processing of the feed, resist inactivation by the proteolytic enzymes encountered in the animal's digestive tract and display high activity at physiological temperature and pH. A series of in vitro experiments were carried out to determine the relative suitability of four major commercial phytase products for use in animal feed. The enzymes assessed lost between 14% and 72% of their original activities after heating to 80 degrees C for 5 minutes. After exposure to simulated upper digestive tract conditions, the phytases assessed retained between 0 and 28% of their original activities. The commercial phytases displayed between 98% and 67% of their maximum activities at 39 degrees C and all phytases assessed had an optimum pH between pH 4 and pH 5. None of the phytases assessed satisfied all of the criteria of an ideal phytase for use in animal feed.

6-Phytase↗
PubMed2004

NICE guidelines for central venous catheterization in children. Is the evidence base sufficient?

BACKGROUND: Recent guidelines from the National Institute for Clinical Excellence (NICE) recommend the use of ultrasound guidance for central venous catheterization in children. This study prospectively examined the use of ultrasound guidance for central venous catheterization in children undergoing heart surgery. METHODS: One hundred and twenty-four infants and children were randomized to either ultrasound-guided or traditional landmark-guided central venous catheterization. RESULTS: Success rates were significantly greater in the landmark group compared with the ultrasound group (89.3% vs 78%, P<0.002), and arterial puncture rates were significantly lower in the landmark group (6.2% vs 11.9%, P<0.03). There was no significant difference between the two groups in the time taken to perform the catheterization. CONCLUSIONS: These results are different from the published results on which the NICE guidelines were based; however, the evidence base in children is small. There is currently insufficient evidence to support the use of ultrasound guidance for central venous catheterization in children.

Carotid Artery Injuries↗
PubMed2002

Elevated alpha-foetoprotein and hepatic metastases--it's not always what it seems!

Gastric cancers that secrete alpha-foetoprotein (AFP) are a rare but well defined entity. These tumours tend to be aggressive with a poor prognosis. Recognition and identification of this group of patients is important in influencing prognosis, treatment options and further clinical research into this entity. We report three cases of gastric cancers associated with elevated AFP. This entity should be considered in patients with hepatic lesions and an elevated AFP without risk factors for hepatocellular carcinoma or in patients with associated gastric symptoms.

Aged↗
PubMed2001

A randomized, controlled trial of a home environmental intervention: effect on efficacy and upset in caregivers and on daily function of persons with dementia.

PURPOSE OF STUDY: The authors determined short-term effects of a home environmental intervention on self-efficacy and upset in caregivers and daily function of dementia patients. They also determined if treatment effect varied by caregiver gender, race, and relationship to patient. DESIGN AND METHODS: Families (N = 171) of dementia patients were randomized to intervention or usual care control group. The intervention involved 5 90-min home visits by occupational therapists who provided education and physical and social environmental modifications. RESULTS: Compared with controls, intervention caregivers reported fewer declines in patients' instrumental activities of daily living (p = .030) and less decline in self-care and fewer behavior problems in patients at 3 months post-test. Also, intervention spouses reported reduced upset (p = .049), women reported enhanced self-efficacy in managing behaviors (p = .038), and women (p = .049) and minorities (p = .037) reported enhanced self-efficacy in managing functional dependency. IMPLICATIONS: The environmental program appears to have a modest effect on dementia patients' IADL dependence. Also, among certain subgroups of caregivers the program improves self-efficacy and reduces upset in specific areas of caregiving.

Activities of Daily Living↗
PubMed2000

Understanding inference as a source of knowledge: children's ability to evaluate the certainty of deduction, perception, and guessing.

Three experiments investigated children's understanding of inference as a source of knowledge. Children observed a puppet make a statement about the color of one of two hidden toys after the puppet (a) looked directly at the toy (looking), (b) looked at the other toy (inference), or (c) looked at neither toy (guessing). Most 4-, 5-, and 6-year-olds did not rate the puppet as being more certain of the toy's color after the puppet looked directly at it or inferred its color than they did after the puppet guessed its color. Most 8 and 9-year-olds distinguished inference and looking from guessing. The tendency to explain the puppet's knowledge by referring to inference increased with age. Children who referred to inference in their explanations were more likely to judge deductive inference as more certain than guessing.

Age Factors↗
PubMed1999

Human dendritic cells express a 95 kDa activation/differentiation antigen defined by CMRF-56.

Despite the unique functions of dendritic cells (DC), only two cell surface antigens (CMRF-44 and CD83) with relatively restricted expression on human DC have been described to date. We describe a third mAb, CMRF-56, which recognizes another DC early activation/differentiation antigen with limited expression on other haemopoietic cell populations. Circulating blood leukocytes did not express the CMRF-56 antigen and, following either in vitro culture or activation of PBMC populations, CMRF-56 antigen expression was detected only on DC and a subpopulation of CD19+ lymphocytes. Circulating blood DC were CMRF-56 but induced expression within 6 h of in vitro culture. This, together with the finding that tonsil and synovial fluid DC upregulate the antigen following short-term in vitro culture, confirmed that CMRF-56 recognizes an early activation antigen on DC. Isolated Langerhan's cells, dermal DC, migratory dermal DC and monocyte derived DC (GM-CSF/IL-4/TNFalpha) also express the CMIRF-56 antigen. Antigen modulation studies demonstrated that the amount of cell surface bound CMRF-56 and CMRF-44 (but not CD83) mAb was dramatically reduced by short-term incubation at 37 degrees C. This effect was not due to internalization and the reduction in CMRF-56 binding was a reversible, temperature-dependent process. In contrast, the decrease in CMRF-44 binding was irreversible, suggesting that following ligation the CMRF-44 antigen undergoes an irreversible conformational change or shedding at 37 degrees C. Western blotting confirmed that CMRF-56 recognizes a previously undescribed 95 kDa activation antigen whose cellular distribution and expression kinetics overlaps with, but is clearly distinguishable from, that of the CD83 and CMRF-44 antigens. CMRF-56 therefore provides a useful additional marker for studies on human DC.

Antibodies, Monoclonal↗
PubMed1998

Identification of medications that cause cognitive impairment in older people: the case of oxybutynin chloride.

OBJECTIVES: To evaluate the cognitive effects of acute challenges with the antispasmodic agent oxybutynin hydrochloride in normal older volunteers and to compare these effects with those attributable to diphenhydramine, another commonly used medication with anticholinergic (muscarinic-blocking) activity. DESIGN: A double-blind, placebo-controlled cross-over study. SETTING: Laboratory evaluations of community subjects. PARTICIPANTS: A convenience sample of 12 volunteers, average age 69.17 years. INTERVENTION: Baseline assessment was followed by randomized administration of a placebo, oxybutynin hydrochloride (5 and 10 mg), and diphenhydramine hydrochloride (50 mg) in test sessions separated by 1 week. MEASUREMENTS: Evaluation of cognitive performance with a 1-hour battery of pencil and paper, interviewer-administered, and computer-administered tests beginning 90 minutes after drug (or placebo) administration. RESULTS: Random regression analyses demonstrated that oxybutynin caused significant cognitive decrements on seven of 15 cognitive measures, and diphenhydramine caused decrements on five measures. The most sensitive measures for detecting the effects of oxybutynin hydrochloride were the Buschke Selective Reminding Test and Reaction Time. CONCLUSIONS: These findings demonstrate that oxybutynin can cause cognitive impairment and suggest that physicians prescribing it should monitor their patients to facilitate the early recognition of those who experience drug-related cognitive deficits. More generally, the findings demonstrate that systematic research with normal volunteers can identify cognitive toxicity not recognized during the process of drug development or postmarketing surveillance.

Aged↗
PubMed1997

Identification of drug-related cognitive impairment in older individuals. Challenge studies with diphenhydramine.

The authors tested the use of repeated cognitive measures to identify those older individuals who experience cognitive decline after administration of a centrally acting medication. Subjects were 30 medically stable, older volunteers, mean age 71.4. Administration was a double-blind, placebo-controlled, crossover "challenge" from baseline to placebo, 50 mg, or 75 mg of diphenhydramine. More patients exhibited significant cognitive decrements after 75 mg of diphenhydramine than after placebo on the Buschke Selective Reminding Test Total Recall and the Trails B test. Data were consistent with models based on prediction intervals. Quantitative algorithms using prediction equations can characterize the normal limits of within-subject variability and define excessive cognitive change in elderly subjects, showing promise for use in monitoring patients to identify those who experience mild cognitive toxicity from prescribed medications.

Age Factors↗
PubMed1997

Salivary cortisol and daily events in nursing home residents.

The authors evaluated the feasibility of using salivary cortisol as a noninvasive measure of hypothalamic-pituitary-adrenal (HPA)-axis responses to stressful events of daily living in elderly nursing home residents. Ten medically stable male nursing home residents (age 81.7 +/- 12.42) gave salivary samples before and after an assisted bath, and at corresponding times on the subsequent (control) day. Regression models, with measures of salivary cortisol on the bath and control days for two timepoints before the bath and four timepoints after the bath as the dependent variables, yielded significant effects of time, bath status, and day. Salivary cortisol testing is noninvasive and easy to collect from long-term care patients, including those with moderate degrees of dementia. It may be of use as a tool for studying the stressors associated with care, the determinants of HPA responses, and the consequences of hypercortisolemia in these vulnerable patients.

Aged↗
PubMed1993

Breast cancer screening practices among retirement community women.

BACKGROUND: The purposes of this study were (a) to learn more about the existing breast cancer screening practices of women age 65 and older and (b) to identify factors related to breast cancer screening. METHOD: A random sample of 752 women age 65 and older residing in independent living apartments in eight retirement communities was selected to participate in a survey of breast cancer screening practices and related factors. A total of 616 surveys were complete, yielding a response rate of 82%; of those, 571 of the surveys were administered by telephone, with the remaining 45 administered in person. RESULTS: Thirty-eight percent of the women reported having had a mammogram within the past year, 53% had a clinical breast exam, and 39% reported performing monthly breast self-examination. The percentage of women reporting either annual clinical breast examinations or mammography decreased with increasing age. Results of a logistic regression analysis found that having discussed mammography with a physician, believing in the need for mammography, having no mammography-related concerns, and the combination of personal experience with breast cancer and having had a clinical breast examination in the past year were all independently related to having had a mammogram within the past year (P < 0.05). CONCLUSION: In order to increase older women's participation in screening, particularly in mammography, educational interventions need to be developed and directed both to older women and to their physicians.

Age Factors↗
PubMed1992

The impact of mailing psychoeducational materials to women with abnormal mammograms.

A randomized trial was conducted to evaluate the impact of mailed psychoeducational materials on adherence to subsequent annual mammography among women with prior abnormal mammograms. The results showed a 13% increment in adherence among women who received this intervention. This effect was independent of all sociodemographic and medical variables examined. We conclude that mailed psychoeducational materials may be an effective mechanism to improve adherence among women with abnormal mammogram results.

Aged↗
PubMed1991

Psychological and behavioral implications of abnormal mammograms.

OBJECTIVE: To evaluate women's psychological responses to abnormal mammograms and the effect on mammography adherence. To identify psychological responses and other factors that predict mammography adherence in women with normal or abnormal mammograms. DESIGN: Survey study with prospective analysis of factors associated with mammography adherence. SETTING: Health Maintenance Organization of Pennsylvania and New Jersey (HMO PA/NJ). PATIENTS: Study patients, members of HMO PA/NJ who were 50 years of age or older, and who had had mammography done 3 months earlier, included women with normal mammograms (n = 121), women with low-suspicion mammograms (n = 119), and women with high-suspicion mammograms (n = 68), but not women with breast cancer. MEASUREMENTS: Psychological responses 3 months after mammography and adherence to subsequent annual mammography were assessed. MAIN RESULTS: Women with high-suspicion mammograms had substantial mammography-related anxiety (47%) and worries about breast cancer (41%). Such worries affected the moods (26%) and daily functioning (17%) of these women, despite diagnostic evaluation excluding malignancy. For each variable, a consistent trend (P greater than 0.05) was seen with degree of mammogram abnormality. Sixty-eight percent of women with normal results, 78% of women with low-suspicion results, and 74% of women with high-suspicion results obtained their subsequent annual mammograms (P greater than 0.05). The number of previous mammograms (odds ratio, 3.2; 95% CI, 1.6 to 6.2) and the effect of the previous results on concerns about breast cancer (odds ratio, 0.5; CI, 0.2 to 1.0) were independent predictors of adherence in logistic regression analyses (P less than 0.05). CONCLUSIONS: A substantial proportion of women with suspicious mammograms have psychological difficulties, even after learning that they do not have cancer. Such sequelae do not appear to interfere with subsequent adherence.

Aged↗
PubMed1991

Psychological side effects of breast cancer screening.

Evaluated the impact of receiving abnormal mammogram results on women's anxiety and breast cancer worries and on their breast self-examination (BSE) frequency and intentions to obtain subsequent mammograms. A telephone survey was conducted with 308 women 50 years old and older approximately 3 months following a screening mammogram. Subjects included women with suspicious abnormal mammograms, nonsuspicious abnormal mammograms, and normal mammograms. Women with suspicious abnormal mammograms exhibited significantly elevated levels of mammography-related anxiety and breast cancer worries that interfered with their moods and functioning, despite the fact that diagnostic work-ups had ruled out breast cancer. Women with moderate levels of impairment in mood or functioning were more likely to practice monthly BSE than women with either high or low levels of impairment. Breast cancer worries, perceived susceptibility to breast cancer, and physician encouragement to get mammograms all exhibited independent positive relationships to mammogram intentions.

Adaptation, Psychological↗
PubMed1976

Classical and "true" gestational postmaturity.

In a study of a sample of 317 conceptional basal body temperature (BBT) curves obtained from normal women, the authors have applied new definitions of prematurity and postmaturity which take into account the time of ovulation. They were thus able to estimate (1) the error rates associated with the classical definitions-incorrect classification as pre- or postmature and nondetection; in particular, for this series, the percentage of incorrectly classified postmatures is high (70 per cent) and is even more so when considering only the unwanted births (80 per cent); (2) the order of magnitude in terms of days of the error made in assessing postmaturity by the classical method. This was found to be quite substantial for the misclassified cases.

Body Temperature↗
PubMed1976

[Length of gestation and parameters of the menstrual cycle].

In studying the BBT curves of 433 conceptional cycles, no evidence was found of any correlation between duration of gestation counted from "zero" day, the last day of the hypothermic phase, and various parameters measuring durations or temperatures evaluated from the curves. There is, in particular, no positive correlation with the duration of the hypothermic phase; and the authors were able, by taking into account the error made in replacing ovulation by "zero" day, to deduce that the "true" duration of gestation is not correlated with the "true" length of the preovulatory phase or indeed with the length of the cycle.

Body Temperature↗
PubMed1975

Smoking, human placental lactogen and birth weight.

Human placental lactogen (HPL) was measured in 525 serum samples from 144 pregnant women and related to smoking habits and the birth weight of their infants. Women smoking during pregnancy were found to have a level of HPL significantly lower than the non-smokers (p less than 0.05). A significant correlation between HPL and birth weight was found (r=0.38); p less than 0.001) which remained significant when smoking was held constant (r=0.35; p less than 0.001). There was no relationship between birth weight and smoking when HPL was held constant.

Birth Weight↗