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Biomedical subjects

M Conaway

Publications and source records attributed to M Conaway.

14 recordsLinked to original sources
PubMed2001

Health status of children with moderate to severe cerebral palsy.

The aim of the study was to evaluate the health of children with cerebral palsy (CP) using a global assessment of quality of life, condition-specific measures, and assessments of health care use. A multicenter population-based cross-sectional survey of 235 children, aged 2 to 18 years, with moderate to severe impairment, was carried out using Gross Motor Function Classification System (GMFCS) levels III (n = 56), IV (n = 55), and V (n = 122). This study group scored significantly below the mean on the Child Health Questionnaire (CHQ) for Pain, General Health, Physical Functioning, and Impact on Parents. These children used more medications than children without CP from a national sample. Fifty-nine children used feeding tubes. Children in GMFCS level V who used a feeding tube had the lowest estimate of mental age, required the most health care resources, used the most medications, had the most respiratory problems, and had the lowest Global Health scores. Children with the most severe motor disability who have feeding tubes are an especially frail group who require numerous health-related resources and treatments. Also, there is a relationship among measures of health status such as the CHQ, functional abilities, use of resources, and mental age, but each appears to measure different aspects of health and well-being and should be used in combination to reflect children's overall health status.

Activities of Daily Living↗
PubMed2001

Tests for order restrictions in binary data.

In this article, a general procedure is presented for testing for equality of k independent binary response probabilities against any given ordered alternative. The proposed methodology is based on an estimation procedure developed in Hwang and Peddada (1994, Annals of Statistics 22, 67-93) and can be used for a very broad class of order restrictions. The procedure is illustrated through application to two data sets that correspond to three commonly encountered order restrictions: simple tree order, simple order, and down turn order.

Animals↗
PubMed2001

Dual X-ray absorptiometry assessment of body composition in children with altered body posture.

Many children have contractures and/or deformities that preclude positioning in a fully supine position. The purpose of this study was to evaluate the effects of "poor" positioning on the assessment of body composition with dual X-ray absorptiometry (DXA) in thirty-seven normal child volunteers ages 3-16 yr. Multiple whole-body DXA scans of each child were performed: duplicate scans in the correct fully supine position, two scans while simulating different positions typical of children with contractures, and a scan while positioned in the full lateral position as a "worst-case" scenario. Also evaluated were the precision of duplicate measures in the altered positions, the effect of knee flexion contractures, and the impact of metallic orthopedic fixation devices. Errors in body composition assessment did occur from "poor" positioning. In those positions simulating children with contractures, the mean errors were 4-6% for measures of bone mineral content, 1-3% for lean body mass, and 5-11% for fat mass. Measures in the correct fully supine position and the contracted positions were highly correlated. The errors obtained by altering position were small. If errors of this magnitude are of significance, then corrective equations could be utilized to improve accuracy. Precise and reasonably accurate measures of body composition can be obtained with DXA in children with disabilities and deformities that preclude fully supine positioning.

Absorptiometry, Photon↗
PubMed2000

A randomized study comparing standard versus moderately high dose megestrol acetate for patients with advanced prostate carcinoma: cancer and leukemia group B study 9181.

BACKGROUND: Megestrol acetate (MA) is a synthetic progestin with reported activity in both hormone-sensitive and hormone-refractory prostate carcinoma (HRPC). Based on limited data suggesting a possible dose-response effect, a trial was initiated to compare standard versus moderately high dose MA in HRPC. METHODS: One hundred forty-nine men with hormone-refractory prostate carcinoma were randomized to receive oral MA either at 160 mg/day (low dose) or 640 mg/day (high dose). Patients were stratified by performance status and measurable versus evaluable disease. The primary end point was tumor response. Secondary end points were survival, quality-of-life measures, and prostate specific antigen (PSA) decline. RESULTS: The median survival times of 11.2 months for patients who received the low dose and 12.1 months for patients who received the high dose therapy were not significantly different. Best response was equivalent in the 2 arms: 2 partial responses and 22 patients with stable disease for the 160 mg/day dose, and 1 partial response and 28 patients with stable disease for the 640 mg/day dose. A greater than 50% decline in PSA occurred in 13.8% and 8.8% of patients in the low and high dose treatment arms, respectively. There were no differences in the toxicity or quality-of-life outcomes between the two arms. Poorer performance status (2 vs. 0-1), greater than 5% weight loss, higher baseline PSA, and measurable disease all predicted shorter survival. CONCLUSIONS: MA has limited activity in hormone-refractory prostate carcinoma, and there is no apparent dose-response correlation.

Adenocarcinoma↗
PubMed2000

Estradiol hypersensitivity and mitogen-activated protein kinase expression in long-term estrogen deprived human breast cancer cells in vivo.

Women with breast cancer who have responded to initial hormonal therapy frequently experience additional remissions upon further endocrine manipulation. We postulate that hypersensitivity to estradiol (E2) may serve as a mechanistic explanation for these secondary responses. We previously provided evidence of hypersensitivity using an in vitro breast cancer model system and demonstrated the role of mitogen-activated protein kinase (MAP kinase) in the process of adaptation to long-term estradiol deprivation. In the present study, we wished to demonstrate that hypersensitivity to E2 could occur under more complex in vivo conditions and that MAP kinase activation is enhanced under these circumstances. We used an MCF-7 breast cancer model system involving long-term estradiol deprived (LTED) cells to produce xenografts in nude mice and an E2 clamp method to precisely control sex steroid levels. The E2 clamp was designed to maintain plasma E2 at a series of doubling doses from 1.25 pg/ml to 20.0 pg/ml in oophorectomized nude mice. As evidence of the validity of the clamp method, a uterine weight bioassay revealed an excellent, linear dose-response relationship between the predicted level of plasma E2 and stimulation of uterine weight. As evidence of hypersensitivity, we found that LTED xenograft tumors grew to a greater extent than wild-type in response to E2 concentrations of 1.25 pg/ml (P = 0.003) and 2.5 pg/ml (P = 0.0002). At the 10.0 and 20.0 pg/ml plasma concentrations, the LTED tumors were stimulated to a lesser extent than the wild-type. This pattern of increased growth at lower concentrations and reduced growth vs. the wild-type at higher concentrations mimics closely the pattern seen for LTED cells in vitro. All LTED cell tumors exhibited enhanced activation of MAP kinase ranging from 18 to 25%, and E2 did not increase this further. In contrast, E2 caused a linear increase in the percentage of activated MAP kinase positive cells (P < 0.0001) in wild-type tumors from basal levels of 2.66% to maximal levels of 6.40%. These observations suggest a dynamic interplay whereby activation of MAP kinase renders cells more sensitive to the proliferative effects of E2. The precise mechanisms for this interplay are unknown but, when further understood, could potentially provide insight into approaches to prevent the evolution of tumors to a hormone insensitive state.

Animals↗
PubMed2000

High-versus low-threshold surfactant retreatment for neonatal respiratory distress syndrome.

UNLABELLED: Surfactant therapy has become an effective standard therapy for infants with respiratory distress syndrome (RDS). The first dose may be given either as prophylaxis immediately after delivery, or as rescue after an infant has developed RDS. Second and subsequent doses are currently recommended by the manufacturers to be administered at minimal levels of respiratory support. PURPOSE: This study compared the relative efficacy of administering second and subsequent doses of Infasurf surfactant at a low threshold (FIO(2) >30%, still requiring endotracheal intubation) versus a high threshold (FIO(2) >40%, mean airway pressure >7 cm H(2)O) of respiratory support. METHODS: A total of 2484 neonates received a first dose of surfactant; 1267 reached conventional retreatment criteria and were randomized to be retreated according to low- or high-threshold criteria. They were then retreated at a minimum of 6-hour intervals each time they reached their assigned threshold until receiving a maximum of 4 total doses. Subjects were stratified by whether they received their first dose by prophylaxis or rescue and by whether their lung disease was considered complicated (evidence of perinatal compromise or sepsis) or uncomplicated. RESULTS: Among the patients randomized, 33% of prophylaxis and 23% of rescue subjects met criteria for the complicated stratum. Although infants allocated to the high-threshold strategy were receiving slightly more oxygen at 72 hours, there was no difference in the number receiving mechanical ventilation at 72 hours or in the secondary respiratory outcomes (requirement for supplemental oxygen or mechanical ventilation at 28 days, supplemental oxygen at 36 weeks' postconceptional age, inspired oxygen concentration >60% at any time). However, there was a significantly higher mortality for infants with complicated RDS who had received retreatment according to the high-threshold strategy. CONCLUSIONS: We conclude that equal efficacy can be realized by delaying surfactant retreatment of infants with uncomplicated RDS until they have reached a higher level of respiratory support than is the current standard. We speculate that this would result in a substantial cost-saving from less utilization of drug. Conversely, we believe that infants with complicated RDS should continue to be treated by the low-threshold retreatment strategy, which is currently recommended by the manufacturers of the commercially available surfactants.

Biological Products↗
PubMed1999

Hydrocortisone with or without mitoxantrone in men with hormone-refractory prostate cancer: results of the cancer and leukemia group B 9182 study.

PURPOSE: Approximately 40,000 men die each year of hormone-refractory prostate cancer (HRPC). The results of treatment with chemotherapy have been disappointing to date, with no trials demonstrating a benefit with respect to survival duration. Corticosteroids and mitoxantrone each have been shown to be active agents in this disease. The purpose of this study was to demonstrate an advantage of mitoxantrone and hydrocortisone (M+H) over hydrocortisone alone with respect to survival duration. PATIENTS AND METHODS: Two hundred forty-two patients with HRPC were randomized to receive either M+H or hydrocortisone alone. Patients were monitored for survival, time to disease progression, time to treatment failure, response, and quality-of-life (QOL) parameters. RESULTS: Treatment in both arms was well tolerated. Although there was a delay in time to treatment failure and disease progression in favor of M+H over hydrocortisone alone, there was no difference in overall survival (12.3 months for M+H v 12.6 months for hydrocortisone alone). There was an indication that QOL was better with M+H, in particular with respect to pain control. CONCLUSION: M+H generated more frequent responses and a delay in both time to treatment failure and disease progression compared with hydrocortisone alone. In addition, there was a possible benefit of M+H with respect to pain control over hydrocortisone alone. No improvement in survival was observed. Although M+H could be viewed as a palliative option for patients with HRPC, new drugs and novel strategies are needed to improve survival for this disease.

Aged↗
PubMed1998

Cell surface density of p185(c-erbB-2) determines susceptibility to anti-p185(c-erbB-2)-ricin A chain (RTA) immunotoxin therapy alone and in combination with anti-p170(EGFR)-RTA in ovarian cancer cells.

Approximately 30% of ovarian and breast cancers overexpress p185(c-erbB-2) with as many as 10(6) receptors/cell. Normal cells have as few as 10(4) receptors/cell. We have examined the susceptibility of SKOv3 human ovarian cancer cells to anti-c-erbB2 antibodies and immunotoxins as a function of c-erbB-2 density on the cell surface. A panel of SKOv3 clones that expressed different densities of p185(c-erbB-2) receptor were generated through transfection with the c-erbB-2 gene. A significant correlation was found between p185(c-erbB-2) density and susceptibility to killing by anti-p185(c-erbB-2)-ricin A chain (anti-p185(c-erbB-2)-RTA) immunotoxins. With 10(5) copies/cell of p185(c-erbB-2), <10% of clonogenic ovarian cancer cells could be eliminated, whereas in clones that expressed 10(6) copies/cell of p185(c-erbB-2), 99.9% of clonogenic tumor cells were killed. In cell lines that overexpressed p185(c-erbB-2) and also expressed p170(EGFR), anti-p185(cerbB-2)-RTA and anti-p170(EGFR)-RTA immunotoxins exerted synergistic cytotoxicity. Treatment with the two immunotoxins could eliminate 99.99% of clonogenic cells. Importantly, tumor cells that had survived first treatment with anti-p185(c-erbB2)-RTA alone still retained sensitivity to repeat treatment with the same immunotoxin and also proved susceptible to the synergistic cytotoxicity of anti-p185(cerbB-2)-RTA in combination with anti-p170(EGFR)-RTA. Growth characteristics of the clones expressing various levels of p185(c-erbB-2) were also studied. No correlation was found between p185(c-erbB-2) expression levels and the rate of anchorage-dependent growth, anchorage-independent growth, or in vivo growth in nude mice.

Animals↗
PubMed1996

Colorectal screening patterns and perceptions of risk among African-American users of a community health center.

This study investigated risk perceptions and screening patterns for colorectal cancer among predominately low-income African-Americans age 50 and older who used a community health center. The majority of respondents either rated their risk as below average (36%) or did not know their risk (37%) for colorectal cancer. Individuals who provided a risk estimate versus those who did not know their risk were younger and held more accurate beliefs about colorectal cancer. Attributions of perceived risk best distinguished respondents who evaluated their risk to be below average versus average and above average. Compared to respondents who could not explain their risk, those who provided psychological, personal action, and heredity causes were more likely to view their risk as below average than average or above average. In comparison to national norms, these subjects reported higher frequencies of ever having had a digital rectal exam (DRE, 90%), fecal occult blood test (FOBT, 75%) and sigmoidoscopy (SIG, 33%). Moreover, 63%, 53%, and 81% reported their most recent screening for DRE, FOBT, and SIG, respectively, in accordance with ACS and NCI recommended guidelines. However, a subsequent medical audit failed to confirm these self-reports. These results suggest that: 1) educational efforts are needed to enhance knowledge and accuracy of risk perceptions for colorectal cancer; 2) further studies on attributions of risk are needed that may prove useful for developing intervention programs, and 3) studies need to interpret self-report data for colorectal cancer with caution.

Black or African American↗
PubMed1995

Relationship between race and interval to treatment in endometrial cancer.

OBJECTIVE: To determine whether the poor prognosis of black women with endometrial adenocarcinoma is due to racial differences in the interval between the onset of abnormal uterine bleeding and hysterectomy. METHODS: Clinical records of all 219 patients (176 white, 39 black, four other) who underwent surgical treatment of endometrial cancer during 1990-1993 at our institution were reviewed to obtain information regarding clinicopathologic features. In addition, the interval between the onset of abnormal uterine bleeding and hysterectomy was noted. RESULTS: Compared with white patients, black women with endometrial cancer had a significantly higher incidence of unfavorable features, including non-endometrioid histology (38 versus 12%), stage III or IV disease (51 versus 19%), grade 3 differentiation (49 versus 18%), and poor survival (P = .003). There was no significant difference in the median interval from onset of abnormal uterine bleeding to hysterectomy between blacks (11.1 weeks) and whites (13.7 weeks), nor was the interval to treatment related to stage, grade, histologic type, myometrial invasion, or survival. In contrast, patients with a history of hormone use had a longer median interval from the onset of abnormal bleeding to treatment compared with patients who had not used hormones (19 versus 10 weeks) (P < .01), and hormone use was associated with favorable clinicopathologic features and survival. Although black women were less likely to have used hormones than white women (13 versus 44%) (P < .001), racial differences in stage, grade, and survival persisted after correcting for hormone use. CONCLUSION: This study confirms that black women with endometrial cancer have a poorer outcome than white women; however, this does not appear to be due to a difference in the interval from onset of abnormal uterine bleeding to hysterectomy.

Adenocarcinoma↗
PubMed1995

Knowledge, beliefs, and prior screening behavior among blacks and whites reporting for prostate cancer screening.

OBJECTIVES: A survey to determine prostate cancer-related knowledge, beliefs, and prior screening behavior was administered to men participating in prostate cancer screening events at nine major sites in the southeast. Since prostate cancer disproportionately affects blacks, a primary focus of the analysis was to determine if differences in responses exist between racial groups. METHODS: A 20-question, multiple-choice survey to ascertain prostate cancer knowledge and beliefs, demographics, and health care access information was administered at nine major southeastern sites participating in Prostate Cancer Awareness screening events. Potential differences between the responses of blacks and whites were tested using the Cochran-Mantel-Haenszel test (P < 0.05), adjusting for differences among sites. RESULTS: Major findings of this study on 286 black and 1218 white men are as follows: (1) only 28% of black or white men report that their doctor ever discussed a test for prostate cancer with them; (2) blacks were less likely to have a regular doctor (P = 0.03) or ever to have had a digital rectal examination (P < 0.001) or prostate-specific antigen testing (P = 0.005); (3) blacks were less likely to report knowing someone with prostate cancer (P < 0.001) and were more apt to report their acquaintances experiencing post-treatment impotence than whites (P = 0.03); they were less likely to report that "a man with prostate cancer can lead a normal life" (P < 0.001) or that "men can have prostate cancer without symptoms" (P < 0.001); (4) a substantial number of all men did not know that race and/or heredity are risk factors; and (5) "peace of mind" was the leading reason why men (63% of whites and 50% of blacks) attended prostate cancer screening events. CONCLUSIONS: There are a number of similarities among black and white men regarding knowledge and beliefs related to prostate cancer. Important differences, however, in access to screening, perception of the disease and its treatment, and knowledge of risk factors exist between racial groups and represent significant barriers to early detection among African Americans.

Black or African American↗
PubMed1993

Silicone controversy: a survey of women with breast cancer and silicone implants.

BACKGROUND: During the past 3 years, there has been a highly publicized debate concerning the potential medical complications of silicone breast implants. There have been no studies that have addressed the effect of this controversy on women with a history of breast cancer who have undergone breast reconstruction with silicone implants. PURPOSE: This study was undertaken to understand the concerns of such women regarding their breast reconstructions and to assess what impact the silicone implant controversy had on them. METHODS: One hundred seventy-four randomly selected women who had undergone reconstructive surgery with silicone implants subsequent to mastectomy for treatment of breast cancer were interviewed by telephone from February through May 1992. (A moratorium on use of silicone breast implants, imposed by the Food and Drug Administration, extended from January through April 1992.) These women, a subset of 359 mastectomy/reconstruction patients of one university-based plastic surgeon, had their first permanent prostheses placed between 1985 and 1990. The interview included questions designed to elicit information about women's experiences with reconstruction and reactions to the controversy. RESULTS: All study participants were aware of the controversy surrounding silicone implants. Seventy-six percent stated that breast reconstruction helped them cope with cancer, and only 16% had regrets about reconstruction. Many respondents had misconceptions about the nature of possible complications from silicone implants. Fifty-five percent were worried about the implants, yet only 13% considered having them removed as a result of the controversy. Only 27% indicated they would be completely likely to choose silicone implants again. The majority of women were unwilling to accept substantial risks of complications from implants, but there was variability in the level of risk that respondents would tolerate. CONCLUSIONS: A majority of women who have had breast reconstruction using silicone implants after treatment of breast cancer believe that implants helped them cope with the cancer. However, a sizeable proportion of such women are worried about possible medical complications that may develop as a consequence of silicone breast implants. Many would likely not choose these implants today. IMPLICATIONS: The true risks associated with silicone implants will ultimately be known. In the meantime, health care providers need to address patients' concerns about these implants. Information and guidance regarding the potential benefits and risks of breast implant devices should be provided to women with breast cancer who are considering treatment options.

Adult↗
PubMed1992

Immunisation coverage in Lusaka, Zambia; implications of the social setting.

This paper develops a conceptual framework for examining the process of immunisation and explores the sociodemographic determinants of vaccination in Zambia. About 300 mothers with children under 3 years of age were interviewed in urban Lusaka. The analyses suggest that sociostructural, as well as cultural, processes influence the attrition process and immunisation programmes should focus on the uniqueness of each stage. In addition, programmes to improve women's education and to reduce male gender preferences are needed.

Child, Preschool↗