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Biomedical subjects

J Walton

Publications and source records attributed to J Walton.

At least 37 records · Page 2Linked to original sources
PubMed2000

Environmental Accountability: Who's Kidding Whom?

International declarations and charters have been produced to encourage and support higher education institutions (HEIs) to address their environmental responsibilities. This paper discusses the results of a critical examination of a range of international HEIs that have signed the global environmental Talloires Declaration. It also assesses the Talloires Secretariat (University Leaders for a Sustainable Future, ULSF) and the extent to which this has been a primary stimulus. An international survey was undertaken and the results presented in a discursive format in order to highlight key driving forces, barriers, and opportunities for environmental responsibility in HEIs. Analysis reveals that they occur on two distinct and evolving levels: the macro national framework level and the micro institutional framework level. Survey responses revealed that none of the HEIs have an embedded institutional environmental culture and most did not have all the micro institutional mechanisms in place for an integrated university-wide environmental response. Many of the institutional barriers to environmental responsibility occurred as a result of this lack of strategy. The most significant institutional opportunity cited was enthusiastic individuals, particularly those at senior management or directorate level, and these individuals were found to be a key driving force. Results also showed that environmental reporting along the lines developed by the private sector is a flexible mechanism that can stimulate progress internally and externally and can be cost effectively disseminated via the World Wide Web. Moreover the survey results indicate that ULSF is not currently a primary stimulus for institution wide action.

Journal Article↗
PubMed2000

Structural insights into the mechanisms of agonism and antagonism in oestrogen receptor isoforms.

Here we summarise the results that have emerged from our structural studies on the oestrogen receptor (ER) ligand-binding domain. We have investigated the conformational effects of a variety of ligands on the structures of both ER isoforms. Each class of ligand (agonists, partial agonists and selective oestrogen receptor modulators) induces a unique conformation in the receptor's ligand-dependent transcriptional activation function. Together these studies have broadened our understanding of ER function by providing a unique insight into ER's ligand specificity and the structural changes that underlie receptor agonism and antagonism.

Estradiol↗
PubMed2000

Detection of Gov system antibodies by MAIPA reveals an immunogenicity similar to the HPA-5 alloantigens.

The glycosylphosphatidylinositol-linked platelet protein CD109 carries the biallelic alloantigen system Gov. There is limited information on the incidence of Gov alloantibodies in neonatal alloimmune thrombocytopenia (NAITP), post-transfusion purpura (PTP) and platelet refractoriness. We adapted the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay to the detection of Gov antibodies and determined their incidence in 605 archived samples (112 with HPA antibodies) referred for the aforementioned conditions. Here, we show that CD109 expression was reduced upon platelet storage in saline or by cryopreservation, but was stable when stored as whole blood or therapeutic platelet concentrate. Fourteen of the 605 samples contained Gov alloantibodies (anti-Gova, n = 10; anti-Govb, n = 4), with the majority in platelet refractoriness (n = 9) and, of the remaining five, four in NAITP and one in PTP. In seven cases, no other HPA antibodies were detected, three being NAITP cases. The incidence of Gov antibodies was significantly lower than HPA-1 system antibodies (n = 87), but equalled the number of HPA-5 system antibodies (n = 14) and outnumbered HPA-2 and -3 system antibodies (10 altogether).

Alleles↗
PubMed2000

The use of solid-phase microextraction--gas chromatography in forensic analysis.

A thorough review of the application of solid-phase microextraction (SPME) combined with gas chromatography for the analysis of forensic specimens is presented, including experimental results for several recent applications. The SPME applications covered in this comprehensive review include ignitable liquid residues (also referred to as accelerants), explosive traces, drugs and poisons from biological specimens, and other forensic applications. Recently developed SPME methods are also presented, including the analysis of ignitable liquid residues on human skin, odor signatures, and several drug applications such as free-fraction antipsychotic drug levels, blood alcohol casework, drink-tampering analysis, and gamma-hydroxybutyrate identification without the need for derivatization. SPME is shown to be an inexpensive, rapid, and sensitive method for the analysis of a variety of forensic specimens.

Blood Chemical Analysis↗
PubMed2000

Local fetal signal is not required for maintaining IGFBP gene expression in the human decidua: evidence from extrauterine pregnancies.

Insulin-like growth factor-II (IGF-II) from the invading extravillous cytotrophoblasts (EVTs) and insulin-like growth factor binding proteins (IGFBPs) from the maternal decidua interact at the feto-maternal interface and regulate implantation and placentation. To determine whether a local stimulus from the fetus is important in the regulation of IGFBP gene expression in the human decidua, we compared the expression of IGFBP genes in intra- and extrauterine (tubal) pregnancies. The expression of IGF-II and IGFBP-1 to IGFBP-6 mRNAs was determined by in-situ hybridization in the Fallopian tubes of extrauterine pregnancies and concurrent decidua (n = 6), and in the placentae and Fallopian tubes of intrauterine pregnancies (n = 6). All six IGFBP mRNAs were identified in the decidualized endometrium and decidualized Fallopian tubes of intra- and extrauterine pregnancies, with IGFBP-1 mRNA being the predominant mRNA. IGFBP-4 was the second most predominant mRNA and was slightly more abundant in the decidua of extrauterine pregnancies than of intrauterine pregnancies. IGF-II mRNA was expressed mainly in cells of fetal origin. The fact that the IGFBP mRNAs were expressed similarly in both intra- and extrauterine pregnancies indicates that the local physical stimulus from an implanting fetus is not necessary to induce or maintain decidual IGFBP gene expression.

Decidua↗
PubMed2000

An ode to Osler.

Explore the source record for details and available documents.

Canada↗
PubMed2000

Structural aspects of agonism and antagonism in the oestrogen receptor.

We have determined the three-dimensional structures of both alpha- and beta-forms of the ligand-binding domain of the oestrogen receptor (ER) in complexes with a range of receptor agonists and antagonists. Here, we summarize how these structures provide both an understanding of the ER's distinctive pharmacophore and a rationale for its ability to bind a diverse range of chemically distinct compounds. In addition, these studies provide a unique insight into the mechanisms that underlie receptor activation, as well as providing a structural basis for the antagonist action of molecules, such as raloxifene.

Animals↗
PubMed2000

"A beacon of light". Spirituality in the heart transplant patient.

For the cardiac transplant recipients in this study, spirituality was like a beacon of light, providing illumination and sustaining hope while enduring illness. Spirituality was nurtured by Developing Faith and by the Presence of significant others, health care providers, and the Divine to sustain hope. Spirituality throughout the transplantation process was described by concepts of faith, presence, enduring illness, and sustaining hope. The four dynamic phases of Enduring Illness can assist health care providers in understanding what spirituality means to transplant patients. This conceptual model of spirituality demonstrates the important role that spirituality plays in recovery. Clinical application of this model will allow health care providers involved in the care of cardiac transplant patients to integrate spirituality into their patients' plan of care. With future research, this model can be easily modified and built upon to meet the needs of cardiac transplant patients in all phases of transplantation.

Adaptation, Psychological↗
PubMed1999

Auditory brainstem response forward-masking recovery functions in older humans with normal hearing.

We investigated the auditory brainstem response (ABR) recovery from forward masking using toneburst maskers and probes. Two subject groups matched for hearing thresholds were evaluated: normal-hearing young adults (21-40 years) and older subjects (63-77 years) with normal audiometric thresholds. Stimuli consisted of 1, 4 and 8 kHz tonebursts, with 2-4 cycle rise/fall time and no plateau. Forward maskers were tonebursts of the same frequency, with a 5 ms rise/fall time and a 20 ms plateau time. Probes were presented at 40 dB above threshold, and the forward masker was adjusted to a level that just eliminated the ABR to the 40 dB sensation level toneburst when the probe onset occurred at masker offset. Forward-masker intervals varied from 2 to 64 ms. ABR wave V latencies were similar for the young and old age groups regardless of toneburst frequency. Under forward-masking conditions, wave V latency was prolonged for the shorter intervals, and recovered to baseline latency by 64 ms. The forward-masker recovery functions were nearly identical for the two age groups for the 1 kHz toneburst. In contrast, there were clear differences in the recovery functions for the two age groups for the 4 and 8 kHz tonebursts. Specifically, the mean latency shift was greater for the aged group for forward-masker intervals of 16 ms or less. The two age groups showed identical latency shifts for longer forward-masker intervals. These data demonstrate prolonged recovery from forward masking in older human subjects. As these subjects had audiometric thresholds within normal limits, one plausible interpretation of this finding is that the prolonged recovery time is a manifestation of an aging effect on the central auditory nervous system rather than the periphery.

Acoustic Stimulation↗
PubMed1999

Determinants of the first decade of bone loss after menopause at spine, hip and radius.

This study documented bone loss at three different sites in the early postmenopausal period, and examined potential predictors. Forty-three women underwent repeated measurements of bone density at the lumbar spine, proximal femur and distal radius for up to 14 years. Individual rates of bone loss were calculated for the spine and hip; for radial trabecular bone, rates were calculated separately for two time periods, earlier and later after menopause. In the spine and radius, initially high rates of loss diminished with time after menopause. No positive correlations for bone loss were found between the three sites, suggesting that faster than average bone loss was specific to individual bones. High body mass index (BMI) was significantly protective against fast bone loss at the spine and radius; in the spine, each unit increase in BMI was associated with a approximately 5% reduction in the rate of bone loss. Of the other variables measured (maximum oxygen consumption, lean body mass, fat mass, mean psoas muscle area at the L3 level, hand grip strength as well as anthropometry) only bone densitometry was sufficiently predictive to help guidance on hormone replacement or other prophylactic therapy. The data suggest that the known relationship between excessive leanness and risk of osteoporosis and vertebral fracture after menopause might in part be due to fast post-menopausal bone loss. Because bulk of psoas muscle was associated with low spine loss rates, the data also support a role for applied muscular loading in local maintenance of bone density.

Adult↗
PubMed1999

Physical activity and stages of change in fifth and sixth graders.

The Stage of Change (SC) paradigm was adapted to assess readiness to be or stay physically active among fifth and sixth graders. Students completed a four-item SC survey, the Past Year Leisure Time Physical Activity Questionnaire, and the Modifiable Physical Activity Questionnaire for Adolescents. Precontemplation, contemplation, and preparation stages were grouped as "pre-action" (PRE), and action and maintenance as "post-action" (AX) stages. Nearly 40% of all students were in PRE, compared to 60% of students in AX stages. Twenty-two percent of all students were in the sedentary precontemplation or contemplation stages. Significantly more boys were in maintenance than girls, and more girls than boys were in contemplation. Students averaged 14-21 hours/week of television, video, or computer work, and 1.6 hours/week of physical activity outside of school. Interventions may be targeted at a specific SC to enable a child to move forward along the SC continuum toward an active lifestyle.

Adolescent↗
PubMed1999

Spirituality of patients recovering from an acute myocardial infarction. A grounded theory study.

The purposes of this study were to discover what spirituality means to patients recovering from an acute myocardial infarction and to identify patients' perceptions of how spirituality influences recovery. Using the Glaserian method, spiritual concepts were used for theory building. Spirituality was described as a life-giving force nurtured by receiving presence of the divine, family, friends, health care providers, and creation (core category). Supporting categories were: developing faith, discovering meaning and purpose, and giving the gift of self. Five phases to discovering meaning and purpose were: (a) facing mortality, (b) releasing fear and turmoil, (c) identifying and making lifestyle changes, (d) seeking divine purpose, and (e) making meaning in daily life. Spirituality influenced recovery by providing the participants with inner strength, comfort, peace, wellness, wholeness, and enhanced coping. This substantive theory can be used by holistic nurses to facilitate spirituality in patients recovering from an acute myocardial infarction.

Adaptation, Psychological↗
PubMed1997

Handwriting changes due to aging and Parkinson's syndrome.

Wills signed by elderly people are often contested on the grounds the the signature is different from their earlier specimen signatures. Neurological disease, which can affect handwriting, is very common and progressive amongst elderly people. Handwriting change due to old age and neurological disease is poorly understood. To better understand this subject, we carried out a large methodical study based on almost 200 handwriting specimens of Parkinson patients and age-matched controls. Interestingly, our findings indicate that some of the handwriting changes which occur in these populations tend to resemble forgery indicia although upon close inspection they are distinguishable from them. Thus, document examiners are urged to exercise caution in assessing purported forgeries on wills and other documents signed of written during older age or a writer suffering from neurological disease.

Adult↗
PubMed1997

What is the long-term outcome for patients with very small abdominal aortic aneurysms?

OBJECTIVE: To determine the long-term outcome for patients with abdominal aortic aneurysms (AAA) less than 4 cm in AP diameter (very small AAA). DESIGN: Population-based screening study. MATERIALS AND METHODS: One hundred and forty-two patients who had AAA less than 4 cm at presentation were assessed by ultrasound at intervals of 6-12 months. The records of these patients were reviewed. RESULTS: During the period of follow-up the median annual growth rate for aneurysms while under 3.0 cm was 1 mm, rising to 2 mm when between 3.0 and 3.9 cm, and 3 mm when between 4.0 and 4.9 cm in diameter. Elective aneurysm repair was undertaken when aneurysms exceeded the threshold value, which itself increased from 4 cm to 5.5 cm in the 9 years of follow-up. More patients died with their aneurysm (n = 35) then underwent surgery (n = 23). There was one perioperative death, and three unrelated late deaths after resection. One aneurysm ruptured in a patient who had refused follow-up 5 years previously. CONCLUSIONS: This study suggests that aneurysms less than 4.0 cm diameter are relatively benign, and questions the appropriateness of early intervention.

Adult↗