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C Coffey

Publications and source records attributed to C Coffey.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intravascular brachytherapy physics: report of the AAPM Radiation Therapy Committee Task Group no. 60. American Association of Physicists in Medicine.

Recent preclinical and clinical studies indicate that irradiation using ionizing radiation in the dose range of 15 to 30 Gy may reduce the occurrence of restenosis in patients who have undergone an angioplasty. Several delivery systems of intravascular brachytherapy have been developed to deliver radiation doses in this range with minimal normal tissue toxicity. In late 1995 the American Association of Physicists in Medicine (AAPM) formed a task group to investigate these issues and to report the current state of the art of intravascular brachytherapy physics. The report of this task group is presented here.

Angioplasty, Balloon, Coronary↗
PubMed1998

The course of early smoking: a population-based cohort study over three years.

AIMS: To examine the uptake and course of smoking in a representative adolescent cohort. DESIGN: Six-wave cohort study. PARTICIPANTS: Secondary school students initially aged 14-15 years at 44 schools in the state of Victoria, Australia. MEASUREMENTS: Computerized questionnaire including 7-day retrospective recall for tobacco use. FINDINGS: Prevalence rates for smoking in the past month rose from 25% to 31% and daily smoking 9% to 18% across the 3-year follow-up. Forty-five per cent of the sample smoked at some point but only 18% were daily smokers at the end-point. High rates of short-term cessation were observed for both experimental and daily smokers, but 70% of daily smokers relapsed within 12 months. Occasional smoking at the outset was the strongest predictor of later daily smoking and was also predictive of lower cessation and higher relapse rates. Parental divorce and parental daily smoking were associated with smoking at the outset and parental smoking was strongly predictive of the course of daily smoking. In contrast, prevalence rates of smoking in a subject's school did not significantly predict either smoking initiation or subsequent course. Female daily smokers were half as likely as males to cease smoking, a finding that accounted for gender differences in smoking prevalence in this sample. CONCLUSIONS: The strength of association between occasional and later daily smoking indicates the importance of primary prevention but the variability in the early course indicates that there should be much scope for promotion of adolescent efforts to quit. Both the diminished likelihood of smoking cessation in young women and parental influences on smoking course deserve further exploration.

Adolescent↗
PubMed1998

Randomised controlled trial of biofeedback training in persistent encopresis with anismus.

BACKGROUND: Paradoxical external anal sphincter contraction during attempted defecation (anismus) is thought to be an important contributor to chronic faecal retention and encopresis in children. Biofeedback training can be used to teach children to abolish this abnormal contraction. METHODS: A randomised controlled trial in medical treatment resistant and/or treatment dependent children with anismus using surface electromyographic (EMG) biofeedback training to determine whether such training produces sustained faecal continence. Up to four sessions of biofeedback training were conducted at weekly intervals for each patient. Anorectal manometry was performed before randomisation and six months later. Parents of patients completed the "child behaviour checklist" (CBCL) before randomisation and at follow up. RESULTS: Sixty eight children underwent anorectal manometry and EMG. Of these, 29 had anismus (ages 4-14 years) and were randomised to either EMG biofeedback training and conventional medical treatment (BFT) (n = 14) or to conventional medical treatment alone (n = 15). All but one child were able to learn relaxation of the external anal sphincter on attempted defecation. At six months' follow up, laxative free remission had been sustained in two of 14 patients in the BFT group and in two of 15 controls (95% confidence interval (CI) on difference, -24% to 26%). Remission or improvement occurred in four of 14 patients in the BFT group and six of 15 controls (95% CI on difference, -46% to 23%). Of subjects available for repeat anorectal manometry and EMG at six months, six of 13 in the BFT group still demonstrated anismus v 11 of 13 controls (95% CI on difference, -75% to -1%). Of the four patients in full remission at six months, only one (in the BFT group) did not exhibit anismus. Rectal hyposensitivity was not associated with remission or improvement in either of the groups. Mean CBCL total behaviour problem scores were not significantly different between the BFT and control groups, but there was a significant improvement in CBCL school scale scores in the BFT group, and this improvement was significantly greater than that seen in the control group. CONCLUSIONS: The result of this study, together with those reported in other controlled trials, argues against using biofeedback training in children with encopresis.

Adolescent↗
PubMed1998

Depression, anxiety, and smoking initiation: a prospective study over 3 years.

OBJECTIVES: This report considers the extent to which depression and anxiety predict smoking onset in adolescence. METHODS: A 6-wave cohort design was used to study a sample of 14- and 15-year-old students (n = 2032) drawn from 44 secondary schools in the state of Victoria, Australia. The students were surveyed between 1992 and 1995 with a computerized questionnaire that included a 7-day retrospective diary for tobacco use and a structured psychiatric interview. RESULTS: Experimental smokers were 29 times more likely than non-smokers to make a transition into daily use in the subsequent 6 months. Depression and anxiety, along with peer smoking, predicted initiation of experimental smoking. Specifically, depression and anxiety accentuated risks associated with peer smoking and predicted experimentation only in the presence of peer smoking. CONCLUSIONS: The finding that experimental smoking is an overwhelmingly strong predictor of later daily smoking focuses attention on smoking initiation. Depressive and anxiety symptoms are associated with higher risks for initiation through an increased susceptibility to peer smoking influences. Promoting the psychological well-being of adolescents and addressing perceived interpersonal benefits of smoking may play a role in the prevention of adolescent tobacco use.

Adolescent↗
PubMed1998

Relationship of somatotype and physical characteristics to distance running performance in middle age runners.

BACKGROUND: The purpose of this study was to determine the variance explained by somatotype, selected anthropometric variables, and muscle cross-sectional area (CSA) on 10 km run time. METHODS: Subjects were 19 female and 34 male moderately trained distance runners who competed in a local 10 km road race. Mean ages were 39.7 +/- 9.2 for females and 42.7 +/- 10.3 yr for males. RESULTS: Endomorphy explained 41.0% (R = 0.64, SEE = 6.5 min) of the variance in females' 10 km time, whereas body mass index explained 28.0% (R = 0.53, SEE = 7.8 min) with mesomorphy adding 10.4% (R = 0.62, SEE = 7.3 min) more explained variance in males' running times. With data combined for men and women, endomorphy explained 22.1% (R = 0.47, SEE = 7.9 min) of the variance. CONCLUSIONS: It was concluded that somatotype and body mass index explain a moderate portion of the variance in 10 km run performance in runners heterogeneous in ability. Muscle and muscle plus bone cross-sectional area of related running muscles does not contribute to the explained variance in men. Research seeking to explain sources of variation in running performance should consider including somatotype as an independent variable.

Adult↗
PubMed1997

Adolescent suicidal behaviours: a population-based study of risk.

BACKGROUND: Reports of adolescent suicidal behaviour have generally derived from clinical settings but population-based studies are likely to provide a clearer epidemiological view. METHODS: Non-fatal suicidal behaviours were studied in 1699 Australian 15- to 16-year-old secondary school students at 44 schools in the state of Victoria, Australia. Self-reported episodes of self-harm were characterized using items from the Beck Suicide Intent Scale. RESULTS: The 12 month weighted prevalence estimate for deliberate self-harm was 5.1%. The commonest forms were self-laceration (1.7%), self-poisoning (1.5%) and deliberate recklessness (1.8%). Self-poisoning and self-laceration were commoner in girls. The prevalence of 'true suicide attempts' was 0.2%. Most self-harmers did not perceive death as likely, plan self-harming episodes at length or inform others of the episodes. Psychiatric morbidity had the strongest association with self-harm, an association which held for all subtypes. Antisocial behaviour and substance abuse were associated with self-harm in girls but not boys. Sexual activity was independently associated with self-harm in both genders. CONCLUSIONS: Deliberate self-harm was common but the great majority of episodes were not 'true suicide attempts'. It is, therefore, possible that attributable mortality and morbidity may be greater in self-harmers without definite suicidal intent.

Adolescent↗
PubMed1996

Combined in vitro and in vivo T lymphocyte depletion for the control of graft-versus-host disease following haploidentical marrow transplant.

Most patients requiring allogeneic bone marrow transplantation (BMT) lack a human leukocyte antigen genotypically identical sibling and require an alternative donor. This carries an increased risk of graft failure and acute graft-versus-host disease (GVHD). We sought to overcome these problems with transplants by using grafts obtained from the most readily available source: the haploidentical, partially mismatched, related donor. This study of 40 patients used a novel approach combining in vitro and in vivo T cell depletion with T lymphocyte targeted monoclonal antibodies (mAb) and intensified conditioning therapy, including fractionated total body irradiation before etoposide, cytoside arabinoside, cyclophosphamide, and methylprednisolone. Grafts were treated with T10B9.1A-31 mAb, directed against the alpha-beta heterodimer of the T cell receptor, and rabbit complement. In vivo depletion was attempted with an anti-CD5 mAb-Ricin A-chain (H65-RTA) immunotoxin (IT). Study patients were compared with a historical control group of 17 patients not given H65-RTA. Rates of engraftment were not significantly different (93% vs. 100%, P=0.12), although patients receiving IT engrafted more rapidly. The incidence of > grade I GVHD was significantly lower in the study group (36% vs. 100%, P=0.0001), as well as for severe grade III-IV GVHD (19% vs. 92%, P=0.0001). Five-year survival tended to be improved in the study group (40% vs. 18%, P=0.21). Transplant from haploidentical family members is indicated for patients without a matched sibling in whom allogeneic BMT offers the best opportunity to achieve cure.

Adolescent↗
PubMed1993

Beam profile analysis using GafChromic films.

GafChromic film dosimetry techniques were used to evaluate the beam profiles for each collimator of the Leksell Gamma Knife at the University of Kentucky Medical Center. At the conclusion of acceptance testing, representatives from Leksell exposed conventional films for beam profile processing and analysis in Sweden. At the same time, an inhouse technique using GafChromic films was utilized in the analysis of the beam profiles. GafChromic films were irradiated to 100 Gray to provide data in each of the three planes for each collimator size. The films were analyzed using a scanning helium-neon laser densitometer with a small aperture of 5-10 microns. The digitized density profiles were curve-fitted using a PC plotting algorithm. The curve-fitted density profiles were converted to relative dose using a standard calibration curve determined with a conventional cobalt-60 teletherapy beam. The results are in excellent agreement with the conventional film analysis reported by Leksell. The GafChromic method has proven to be an accurate and rapid method of analysis and could be easily incorporated into a quality assurance program.

Calibration↗
PubMed1992

Tandem-vaginal cylinder applicator for radiation therapy of uterine adenocarcinoma.

Preoperative radiotherapy for stage II adenocarcinoma of the endometrium was studied in 74 patients using the University of Kentucky tandem-vaginal cylinder applicator. The intrauterine tandem and vaginal cylinder were inserted and loaded at the same time or sequentially. Forty to 45 Gy of fractionated whole pelvis photon radiotherapy was combined with the single intracavitary insertion which gave 20 Gy to a parauterine isodose at 2 cm and to the vaginal surface. Treatment with this system gave a 5 year survival rate of 88% with a 4% complication rate for stage II corpus adenocarcinomas.

Adenocarcinoma↗
PubMed1991

Randomised trial of laxatives in treatment of childhood encopresis.

Primary faecal incontinence (encopresis) in children is usually treated with laxative medication and a behaviour modification programme aimed at promoting regular toileting, but the effectiveness of laxatives has never been adequately investigated. 169 children with encopresis and evidence of stool on plain abdominal radiograph were randomly allocated to receive multimodal (MM) therapy (laxatives plus behaviour modification; n = 83) or behaviour modification alone (BM; n = 86). Mean (SD) follow-up was 55.1 (27.0) weeks and 56.7 (32.0) weeks, respectively. By 12 months' follow-up 42 (51%) of the MM group and 31 (36%) of the BM group (p = 0.079) had achieved remission (at least one 4 week period with no soiling episodes) and 52 (63%) vs 37 (43%) (p = 0.016) had achieved at least partial remission (soiling no more than once a week). MM subjects achieved remission significantly sooner than BM subjects, and the difference in the Kaplan-Meier remission curves was most striking in the first 30 weeks of follow-up (p = 0.012). The patterns of compliance with toileting in the treatment groups were almost identical, although about 1 in 8 children overall did not comply with the sitting programme. After exclusion of the 24 poor compliers, there was no significant difference between BM and MM groups. This study shows a clear advantage overall for the use of laxative medication, although the benefit may not be as great for children who are able to maintain regular toileting.

Adolescent↗
PubMed1991

Comparison of participants and nonparticipants in a neuroendocrine investigation of psychosis.

Of all neuroleptic-naive, acutely psychotic subjects admitted to hospital over a 2-year period (n = 62), 27 participated in a neuroendocrine study and 35 did not participate (51% refused consent, 19% were incapable of consent and 31% started neuroleptics immediately). However, all nonparticipants agreed to psychopathological evaluation, thus allowing comparison between participants and nonparticipants. The 2 groups were similar in most respects, except that more nonparticipants were hostile. Among subjects with schizophrenia, 47% of nonparticipants had the paranoid subtype vs 8% of participants. There was also a trend towards longer illness duration in nonparticipants. These results underline the need for neurobiological studies of psychosis to consider sample bias as a confounding variable.

Adult↗
PubMed1989

Esmolol for potentiation of nitroprusside-induced hypotension: impact on the cardiovascular, adrenergic, and renin-angiotensin systems in man.

Esmolol infusion at rates of 200, 300, and 400 micrograms.kg-1.min-1 was used to potentiate hypotension (mean arterial pressure = 60 mm Hg) induced with sodium nitroprusside (SNP) in 10 male patients undergoing radical cancer surgery during nitrous oxide-oxygen and fentanyl anesthesia. Heart rate (HR), blood pressure (radial arterial catheter), and plasma levels of renin activity (PRA), norepinephrine (N), epinephrine (E), and dopamine (D) were measured: 1) while patients were awake; 2) after induction of anesthesia (nitrous oxide, 60% in oxygen, fentanyl = 5 micrograms/kg followed by an infusion at 10 micrograms.kg-1.hr-1); 3) after surgery had begun; 4) after 20 minutes of SNP-induced hypotension; 5) after 20 minutes of esmolol at each of the above infusion rates; and 6) after the completion of surgery. Compared to awake values, SNP-induced hypotension (mean infusion rate = 3.1 micrograms.kg-1.min-1 +/- 0.6 SE) during surgery resulted in significant (P less than 0.05) increases in heart rate, PRA, N, and D. Infusion of esmolol resulted in significant (P less than 0.05) dose-dependent reductions in SNP requirement to maintain MAP = 60 mm Hg. At 200 micrograms.kg-1.min-1, SNP requirement was 2.1 micrograms.kg-1.min-1 +/- 0.4, at 300 micrograms.kg-1.min-1, it was 1.0 micrograms.kg-1.min-1 +/- 0.2, and at 400 micrograms.kg-1.min-1, was 0.5 micrograms.kg-1.min-1 +/- 0.3. Concomitant with the decrease in SNP requirement, there were significant reductions in HR and PRA at all infusion rates of esmolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1988

Rectal carcinoma: treatment with Papillon technique and fiberoptic-guided methods.

An adaptation of the Papillon technique was developed in which a superficial x-ray machine was used for treatment of small superficially invasive rectal carcinomas. Modification of the proctoscope-treatment cone apparatus, including addition of a fiberoptic scope, allows confirmation of accurate cone placement throughout the entire treatment. There is no personnel exposure to radiation. Measured physics beam characteristics are clinically comparable to those reported for the Papillon treatment beam.

Adenocarcinoma↗
PubMed1988

Down-modulation of high-affinity receptors for erythropoietin on murine erythroblasts by interleukin 3.

Erythropoiesis is regulated by the glycoprotein hormone erythropoietin (Epo) and by several other factors including interleukin 3 (IL-3) and granulocyte-macrophage colony-stimulating factor. The possibility that IL-3 and GM-CSF may act by modulating Epo receptor expression was investigated using erythroblasts purified from the spleens of phenylhydrazine-treated mice. AT 37 degrees C, in the presence of sodium azide to inhibit receptor internalization. 125I-labeled human recombinant Epo bound to a single class of high-affinity receptors on splenic erythroblasts (450 sites/cell, Kd = 700 pM). Autoradiographic studies indicated that 94% of specifically bound Epo was associated with erythroblasts, decreased Epo binding being observed with increasing erythroid cell maturation. Whereas recombinant mouse IL-3 and GM-CSF did not compete with 125I-Epo for binding to the Epo receptor, preincubation of cells with IL-3 resulted in a concentration-dependent loss of 125I-Epo binding without altering the affinity of residual receptors for Epo. Complete loss of Epo receptors was effected within 2 h at IL-3 concentrations above 2500 U/ml. Preincubation with recombinant mouse GM-CSF had no effect on binding, even at 100,000 U/ml. In comparison, preincubation of cells with Epo (50 U/ml) caused complete loss of 125I-Epo binding within 30-60 min, an effect not explained by receptor saturation with unlabeled Epo. Thus, in addition to trans-down-modulating growth factor receptors of the granulocyte-macrophage series, IL-3 also trans-down-modulates a growth factor receptor of the erythroid lineage.

Animals↗