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Biomedical subjects

C Fox

Publications and source records attributed to C Fox.

At least 37 records · Page 2Linked to original sources
PubMed2001

Chronic inflammation with increased human immunodeficiency virus (HIV) RNA expression in the vaginal epithelium of HIV-infected Thai women.

Thai residents have a greater risk of heterosexual transmission of human immunodeficiency virus (HIV) than do US residents. To analyze host factors associated with heterosexual transmission, vaginal epithelial biopsies from HIV-seropositive Thai and US women were evaluated for tissue virus load and histologic makeup. In all, 84% of Thai and 14% of US women exhibited a chronic inflammatory T cell infiltrate in the vaginal epithelium. In Thai tissue, the infiltrate was associated with elevated levels of HIV RNA in the epidermis. Uninfected Thai women also had vaginal epithelial inflammation. Inflammation did not correlate with sexually transmitted diseases or HIV disease stage. The higher rates and increased risk of heterosexual transmission in Thailand may be due to chronic inflammation at the site where the virus is transmitted, which leads to the accumulation of activated T cells. Such cells might act as targets for initial viral infection and subsequently as reservoirs that support efficient transmission.

Adult↗
PubMed2001

Changes in vocal loudness following intensive voice treatment (LSVT) in individuals with Parkinson's disease: a comparison with untreated patients and normal age-matched controls.

This study assessed the impact of the Lee Silverman Voice Treatment (LSVT) on vocal loudness [sound pressure level (SPL)] in a group of dysarthric individuals with idiopathic Parkinson's disease (IPD). Pre- to post-treatment changes in SPL in the treated group were compared with changes in voice SPL during the same time in two control groups: individuals with IPD not treated with the LSVT and in non-disordered individuals, age-matched to the patients. All subjects produced the same voice and speech tasks--sustaining vowel phonation, reading the "Rainbow Passage," producing a short monologue, and describing a picture. These tasks were recorded at three different occasions: just prior to treatment, just after treatment, and 6 months following treatment. The individuals treated with LSVT increased voice SPL from baseline to post-treatment by an average of 8 dB and from baseline to 6 months follow-up by an average of 6 dB. These changes were statistically significant and perceptibly audible. No significant changes in SPL were observed in the control groups during the time corresponding to the treatment and follow-up. Differences in SPL between the treated and untreated patients at post-treatment and follow-up were statistically significant for all voice and speech tasks. These findings, along with others, provide additional support for the efficacy of the LSVT.

Aged↗
PubMed2001

Th1 and Th2 cytokine responses to academic stress.

Predominant Th2 profiles are associated with the worsening of asthma, and stress is speculated to induce a Th2 profile. The goals of this study were to examine the responses of the cytokines Th1 (IFN-gamma and IL-2) and Th2 (IL-4, IL-5, and IL-6) to a stressor and to look at the relationships between cytokine and psychological responses. Twenty-four students with and without a history of asthma completed questionnaires and gave blood samples during nonexam and exam periods. Cytokines were measured by ELISA from supernatants of stimulated mononuclear cells (MNC) and whole blood. During examinations, there were a significant decrease in IL-2 and a significant increase in IL-6 production (both cultures) and a significant decrease in IFN-gamma production (MNC cultures). Baseline IL-2 levels showed significant negative correlations with several stress and mood scores. Findings of this study indicate a down-regulation of Th1 and a selective up-regulation of Th2 cytokines during a stressful exposure.

Adult↗
PubMed2001

Comparison of EMG activity of medial and lateral hamstrings during isometric contractions at various cuff weight loads.

Since both the medial head (MH) and lateral head (LH) of the hamstring muscles contribute to knee flexion, this study investigated whether the relative electrical activity of these heads remained constant with respect to each other or changed during isometric contractions at five different resistance levels. The relative electrical activity of these two heads was determined by comparing their integrated EMG (iEMG). Forty-two volunteers with no history of right lower extremity injury or disease, between the ages of 18 and 35, were studied. Following motor point location, surface electrodes were placed over the MH and LH. Subjects, positioned prone, flexed the knee to 45 degrees using a sawhorse as a tactile cue to help maintain this position. Three recordings, 8 s in length, were taken at each subject's maximum isometric contraction and then using cuff weights of 1, 3, 5, and 7% of their body weight. The average of the three recordings was used in the analysis. During maximum isometric contraction (at 45 degrees of knee flexion), the LH contributes a significantly greater percent of the total iEMG (63.4%) than the MH (P < 0.0001). Furthermore, within the four submaximal levels tested, the LH's contribution was significantly greater than the MH (P < 0.01). During submaximal isometric contractions, the LH percent contribution to total iEMG was less than its contribution during maximal isometric contraction, all P values < 0.005. As a result, during these same submaximal isometric contractions, the MH contribution to total iEMG was greater than its contribution during maximal isometric contraction, all P values < 0.005).

Adolescent↗
PubMed2001

Changing thyroid status related to pregnancy.

A case of post-thyroidectomy hypothyroidism is reported. The patient became euthyroid in three consecutive pregnancies, reverting to hypothyroid within three months of delivery on each occasion. The alteration in thyroid status is attributed to pregnancy related changes in antibody titres, though the laboratory data to confirm this are not available.

Adult↗
PubMed2001

Magnesium: its proven and potential clinical significance.

Magnesium is the fourth most abundant cation in the body and is present in more than 300 enzymatic systems, where it is crucial for adenosine triphosphate (ATP) metabolism. Deficiency states result in increased insulin resistance, as well as increased smooth muscle and platelet reactivity. Magnesium deficiency has been shown to correlate with a number of chronic cardiovascular diseases, including hypertension, diabetes mellitus, and hyperlipidemia. Intravenous magnesium has been used therapeutically in critical situations such as status asthmaticus, torsades de pointes, and preeclampsia. Few controlled studies exist regarding the therapeutic uses of oral magnesium supplementation in chronic cardiovascular diseases. Randomized clinical trials are urgently needed to determine whether magnesium supplementation will alter the natural history of these disease states.

Arrhythmias, Cardiac↗
PubMed2000

Rapid activation of lymph nodes and mononuclear cell HIV expression upon interrupting highly active antiretroviral therapy in patients after prolonged viral suppression.

OBJECTIVE: To compare the architecture and HIV-1 RNA and Gag p24 protein expression in lymph nodes (LN) excised from individuals during chronic highly active antiretroviral therapy (HAART) with LN removed from the same patient after plasma virus rebound following the interruption of HAART. MATERIALS AND METHODS: Six HIV-1-infected patients on HAART, with CD4 cell counts greater than 350 cells/microl, and plasma HIV-1 RNA less than 50 copies/ml, underwent inguinal LN excision upon discontinuation of HAART, and again after rebound of plasma virus. Lymph nodes were evaluated by immunohistochemical staining for Gag p24 antigen and Ki67, in-situ hybridization for HIV-1 RNA and H3-histone, and transmission electron microscopy (TEM). RESULTS: LN at baseline were quiescent to mildly hyperplastic and generally contained more primary than secondary follicles. Only one LN had detectable follicular dendritic cell (FDC)-associated p24 antigen, none had HIV RNA. Few mononuclear cells (MNC) expressed RNA or p24 antigen. Plasma virus at the second biopsy ranged from 329 to 3.2 x 10(6) copies/ml. CD4 cell count decline ranged from 5 to 51% during drug hiatus, and was greatest in patients with highest viral rebound. Four of six of the second LN were more hyperplastic than the initial LN, two showed paracortical hyperplasia. MNC expression of HIV RNA in the second LN paralleled the level of plasma viremia. Increased Ki67 and H3-histone signal occurred in the second LN. CONCLUSION: Quiescent LN from individuals on HAART rapidly become hyperplastic and activated within 1-2 months after treatment interruption. As in acute HIV infection, virus expression by LN MNC parallels the rebound in plasma viremia and fall in CD4 cell count.

Antiretroviral Therapy, Highly Active↗
PubMed2000

Neuroendocrine and leukocyte responses and pulmonary function to acute stressors.

Although stress is linked to asthma exacerbation, underlying mechanisms are unclear. Given the shared relevance to stress and asthma, select neuroendocrine and immune responses to acute stressors and their impact on pulmonary function were examined, comparing responses between students with (n = 20) and without childhood asthma (n = 16). Students were challenged with speech and math tasks. Blood samples were collected five times: before tasks, immediately after first and second tasks, and 15 and 60 minutes posttasks. Pulmonary function was measured four times, excluding midtask point. Stress reactivity patterns did not differ between two groups. However, all measures showed significant changes across the challenge. Plasma epinephrine and norepinephrine rose during tasks and declined after tasks, p < .001. Cortisol mainly declined after tasks, p = .03. Leukocyte count increased during tasks with increased lymphocyte percentage that declined after tasks, while neutrophil percentage changed opposite to lymphocytes, p < .001 each. Changes in pulmonary function were significant, p < .05, but were not predicted by the magnitude of neuroendocrine and immune changes. Instead, neuroendocrine and immune levels explained 33%-51% of variance on concurrent pulmonary function. Findings indicate that acute stress induces significant neuroendocrine and immune changes that can affect pulmonary function. However, stress reactivity needs further investigation with larger samples and people with a more severe form of asthma.

Adult↗
PubMed2000

Three-dimensional dose distribution of tangential breast irradiation: results of a multicentre phantom dosimetry study.

BACKGROUND AND PURPOSE: One aspect of good radiotherapeutic practice is to achieve dose homogeneity. Dose inhomogeneities occur with breast tangent irradiation, particularly in women with large breasts. MATERIALS AND METHODS: Ten Australian radiation oncology centres agreed to participate in this multicentre phantom dosimetry study. An Alderson radiation therapy anthropomorphic phantom with attachable breasts of two different cup sizes (B and DD) was used. The entire phantom was capable of having thermoluminescent dosimeters (TLD) material inserted at various locations. Nine TLD positions were distributed throughout the left breast phantom including the superior and inferior planes. The ten centres were asked to simulate, plan and treat (with a prescription of 100 cGy) the breast phantoms according to their standard practice. Point doses from resultant computer plans were calculated for each TLD position. Measured and calculated (planning computer) doses were compared. RESULTS: The dose planning predictability between departments did not appear to be significantly different for both the small and large breast phantoms. The median dose deviation (calculated dose minus measured dose) for all centres ranged from 2. 3 to 5.3 cGy on the central axis and from 2.1 to 7.5 cGy for the off-axis planes. The highest absolute dose was measured in the inferior plane of the large breast (128.7 cGy). The greatest dose inhomogeneity occurred in the small breast phantom volume (median range 93.2-105 cGy) compared with the large breast phantom volume (median range, 100.1-107.7 cGy). There was considerable variation in the use (or not) of wedges to obtain optimized dosimetry. No department used 3D compensators. CONCLUSION: The results highlight areas of potential improvement in the delivery of breast tangent radiotherapy. Despite reasonable dose predictability, the greatest dose deviation and highest measured doses occurred in the inferior aspects of both the small and large breast phantoms.

Breast Neoplasms↗
PubMed2000

Asthma morbidity 6 yrs after an effective asthma self-management programme in a Maori community.

A 6-month Maori community-based asthma self-management programme, involving a "credit card" asthma self-management plan, has previously been shown to be an effective and acceptable system for reducing asthma morbidity. The effectiveness of the asthma self-management programme and participants' self-management behaviour was assessed 6 yrs after the formal end of the programme. Participants were surveyed at the time of enrollment, and 1, 2, and 6 yrs after completing the programme. In each survey, participants were questioned on markers of asthma morbidity and use of medical services during the previous 12 months. Self-management behaviour was assessed using a questionnaire at 2 years and 6 yrs. Of the 69 original participants, 47 (68%) were surveyed after 6 yrs. They generally had reduced severe asthma morbidity and emergency use of health services from baseline. In particular, the proportion who had an emergency visit to a general practitioner had decreased from 41% to 18% (p=0.02). However, the percentage of nights woken due to asthma had returned to preintervention levels, and the proportion of participants taking prescribed regular inhaled steroid had decreased from 91% to 53% (p<0.001). Compared with 2 yrs after completion of the asthma programme, self-management behaviour had also deteriorated, with 29% versus 73% (p<0.001) using their peak flow meter daily when their asthma was "getting bad" and 41% versus 86% (p<0.001) using the "credit card" plan to increase the amount of inhaled steroids in the last year. Although the programme participants were still experiencing reduced morbidity from their asthma 6 yrs after the end of the self-management programme, the benefits were less than those observed at 2 yrs. These findings suggest that under-recognition and under-treatment of asthma with appropriate amounts of inhaled steroids is a major factor contributing to asthma morbidity in this indigenous rural community. To obtain enduring benefits from a self-management system of care continued reinforcement of self-management skills seems to be an essential component of any follow-up.

Adult↗
PubMed2000

Daily energy expenditure in Mexican and USA Pima indians: low physical activity as a possible cause of obesity.

BACKGROUND: Obesity is caused by an imbalance between energy intake and energy expenditure. However, it is unknown whether increased physical activity protects susceptible populations against the development of obesity and type 2 diabetes. OBJECTIVE: To investigate the potential protective role of environment and physical activity against obesity by measuring total energy expenditure in Mexican and USA Pima Indians. METHODS: We compared the physical activity level of 40 (17 female and 23 male; 37+/-11 y, 66+/-13 kg) Mexican Pima Indians from a remote, mountainous area of Northwest Mexico, with 40 age-and-sex matched (17 female and 23 male; 37+/-12 y, 93+/-22 kg) Pima Indians from the Gila River Indian Community in Arizona, USA. We measured total energy expenditure (TEE) by doubly labeled water and calculated physical activity by different methods: physical activity level (PAL) as the ratio of TEE on resting metabolic rate (RMR), TEE adjusted for RMR by linear regression, activity energy expenditure adjusted for body weight (AEE), and activity questionnaire. RESULTS: Physical activity was higher in Mexican Pima Indians when compared with USA Pima Indians as assessed by PAL (1.97+/-0.34 vs 1.57+/-0.16, P<0.0001), TEE adjusted for RMR (3289+/-454 vs 2671+/-454 kcal/day, P<0.0001) and AEE adjusted for body weight (1243+/-415 vs 711+/-415 kcal/day, P<0. 0001). Questionnaires revealed more time spent on occupational activities among Mexican Pima compared with USA Pima (23.9+/-13.3 vs 12.6+/-13.9 h/week, P<0.001). CONCLUSION: These data support a significant role for physical activity in the prevention of obesity in genetically susceptible populations. International Journal of Obesity (2000)24, 55-59

Adult↗
PubMed2000

Intervention studies to reduce the prevalence and incidence of pressure sores: a literature review.

Much has been written about the prevention of pressure sores. However, electronic and manual searches located only 10 studies within the literature in the UK that described interventions able to reduce either their incidence or prevalence. All the studies located contained serious methodological flaws. Apparent success in reducing the number or severity of pressure sores could have resulted because staff involved in data collection were aware that the study was being undertaken and thus took more interest in pressure area care. From the review findings it is apparent that there is a dearth of research evidence upon which to base practice in the sphere of pressure sore prevention and further research is urgently required.

Humans↗
PubMed2000

Evaluating support surfaces for patients in transit through the accident and emergency department.

Little attention has been given to pressure area care for patients admitted via the accident and emergency department (A & E) in UK hospitals, despite evidence that they may wait for considerable periods on hard surfaces, placing them at risk of tissue damage. The literature was searched, and in the absence of existing guidelines to evaluate the suitability of the standard hospital trolley for use with emergency admission patients, criteria were developed by consensus among stakeholders with relevant expertise who were employed in an acute NHS hospital trust. Audit of the existing patient support surfaces using these criteria revealed deficiencies in all of them. Some of the problems identified were related to deterioration of the equipment; others were related to its design. The criteria were used to inform the purchase of new equipment, and a system of auditing to improve pressure area care for emergency admission patients has been established in the trust. The initiative has also drawn attention to significant omissions in the literature relating to pressure area care, including the need to evaluate patient comfort and inclusion of consumer views.

Acute Disease↗