PubMed Health⌕ Search

Biomedical subjects

R Fletcher

Publications and source records attributed to R Fletcher.

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

Indications for Cardiac Pacemaker Implantation in Myotonic Dystrophy.

OBJECTIVES: To determine risk factors for cardiac complications in patients with myotonic dystrophy, and to determine whether permanent cardiac pacemakers may be beneficial in the treatment of myotonic dystrophy heart disease. BACKGROUND: Myotonic dystrophy affects the cardiac conduction system. Cardiac pacemakers are easily implanted and can be life-saving in patients with severe or complete heart block. METHODS: A total of 94 patients with myotonic dystrophy were examined; 46 were followed for a mean of 6.4 (+/- 3.5 SD) years to determine predictors of the end point events of sudden death, Stokes-Adams attacks, or onset of atrial fibrillation. The end points were chosen to determine when cardiac pacemakers should be implanted (Fig. 1). RESULTS: Four out of 5 patients (and all 4 patients >60 years of age) with PR intervals longer than 275 msec had sudden death (n=1), Stokes-Adams attacks (n=1), or onset of atrial fibrillation (n=2). Conversely, only 1 of 89 patients with a PR interval shorter than 275 msec had end point events; 1 patient, aged 63 years, developed left bundle branch block and palpitations accompanied by dyspnea, which responded to a pacemaker. CONCLUSIONS: We recommend that patients with myotonic dystrophy and any indication or a family history of myotonic heart disease have at least a yearly electrocardiogram, particularly if they have a prolonged baseline or progressively increasing PR interval, or symptoms suggestive of heart block.

Journal Article↗
PubMed1999

Factors determining end-expiratory alveolar pressure after cardiac surgery.

Intrinsic positive end-expiratory pressure can occur when the sternum is closed following cardiac surgery, causing anaesthetic and surgical problems. We measured intrinsic positive end-expiratory pressure after sternal closure in two studies of patients undergoing coronary artery bypass grafting with the same anaesthetic regime. In one, patients were ventilated at 10 breaths min-1, in the other they were randomized to be ventilated at 10 or 20 breaths min-1. After sternal closure, intrinsic positive end-expiratory pressure increased significantly, especially in patients in whom it had been present before sternotomy. Multiple linear regressions with the pooled data from the studies showed that intrinsic positive end-expiratory pressure was positively correlated with ventilatory rate (P < 0.005), age (P < 0.005) and Body Mass Index (P < 0.0005), and negatively with FEV1, as percentage of predicted (P < 0.01). There was no correlation between intrinsic positive end-expiratory pressure and a history of smoking. As there was no difference in expiratory resistance between patients ventilated at the two different rates, any effect on intrinsic positive end-expiratory pressure of the higher ventilatory rates could have been due only to the shorter expiratory time.

Age Factors↗
PubMed1998

Spontaneous conversion and maintenance of sinus rhythm by amiodarone in patients with heart failure and atrial fibrillation: observations from the veterans affairs congestive heart failure survival trial of antiarrhythmic therapy (CHF-STAT). The Department of Veterans Affairs CHF-STAT Investigators.

BACKGROUND: In a multicenter, double-blind, placebo-controlled study, the long-term effects of amiodarone on morbidity and mortality in patients with congestive heart failure (CHF) and atrial fibrillation (AF) were evaluated during a 4-year period. METHODS AND RESULTS: Of 667 patients with CHF, 103 (15%) had AF at baseline. Of these, 51 were randomized to amiodarone and 52 to placebo. The group with sinus rhythm and the group in AF were comparable except for a higher proportion of AF in patients with nonischemic versus ischemic cardiomyopathy (41% versus 27%, P<0.005). The mean ventricular response (VR) during AF over 24 hours was reduced by amiodarone at 2 weeks (20%, P=0.001), at 6 months (18%, P=0.001), and at 12 months (16%, P=0.006). Maximal VR was reduced 22% (P=0.001) at 2 weeks, 19% (P=0.001) at 6 months, and 14% (P=0.001) at 12 months. Sixteen of 51 patients on amiodarone and 4 of 52 on placebo converted to sinus rhythm during the study (chi2=9.23, P=0.002). During follow-up, 11 of 268 patients in sinus rhythm on amiodarone at baseline and 22 of the 263 in sinus rhythm on placebo developed AF; the difference was significant (chi2=12.88, P=0.005). Analysis of total mortality during follow-up showed a significantly lower mortality rate (P=0. 04) in patients in AF at baseline who subsequently converted to sinus rhythm on amiodarone than in those who did not convert to sinus rhythm on the drug. CONCLUSIONS: In patients with CHF, amiodarone has a significant potential to spontaneously convert patients in AF to sinus rhythm, with patients who convert having a lower mortality rate than those who do not. The drug prevented the development of new-onset AF and significantly reduced the VR in those with persistent AF.

Aged↗
PubMed1998

Inhibins, activins, and follistatins: expression of mRNAs and cellular localization in tissues from men with benign prostatic hyperplasia.

BACKGROUND: The transforming growth factor beta (TGF beta) superfamily of growth factors includes activins and inhibins, which have been shown to be present in the rat ventral prostate, and human prostate tumor cell lines, although their localization in benign prostatic hyperplasia (BPH) tissue is currently unknown. METHODS: BPH tissues were obtained at surgery, and the mRNA expression for the inhibin alpha, beta A, beta B subunits, the putative activin beta C subunit, the activin type II receptor (ActRII), and the activin binding protein, follistatin, was determined by reverse transcription polymerase chain reaction (RT-PCR) and Southern blot analysis. Antibodies specific for alpha, beta A, beta B, activin A, and follistatin were used to determine the localization of these proteins in BPH tissue specimens. RESULTS: Southern blot analysis confirmed that mRNA for ActRII, beta C subunit, and follistatin was present in all biopsy samples assayed. However, alpha, beta A, and beta B subunit mRNA expression was variable between patient samples. Immunohistochemistry demonstrated the predominant localization of beta A, beta B, and activin A proteins to the epithelium of BPH tissues. No immunoreactivity for the inhibin alpha subunit was detected; follistatin immunoreactivity was localized to the fibroblastic stroma. CONCLUSIONS: The compartmentalization of activin subunit proteins to the epithelium, and of follistatin to the stroma, suggests that a paracrine interaction occurs between the activin ligands and follistatin-binding proteins in BPH tissue.

Activin Receptors↗
PubMed1998

Breast cancer rescreening in low-income women.

INTRODUCTION: Routine mammography screening with clinical breast examination is effective in reducing breast cancer mortality. The Breast and Cervical Health Program (BCHP) in Washington State provides free breast and cervical cancer screening for low-income women, with an emphasis on women of color. This study examined initial breast cancer rescreening and factors associated with rescreening for women enrolled in BCHP in King County, Washington. METHODS: Data were obtained from the Washington State BCHP tracking system. We estimated the percentages who received breast cancer rescreening for women enrolled between July 1994 and December 1995 using survival analysis. Cox proportional regression was also used to examine factors associated with time-until-rescreening. RESULTS: Survival analysis showed that the overall percentages rescreened at 15 and 27 months for women aged 50-69 were 25.7% and 45.0%, respectively. For women aged 40-49, the corresponding percentages were 26.0% and 40.3%. Rescreening differed by age groups, race/ethnicity, level of education, foreign born status, history of previous mammography, and enrollment clinic. CONCLUSIONS: Results from this study suggested that in addition to initial efforts for enrollment, screening programs should emphasize increased rescreening especially for women with certain demographic and screening history characteristics.

Adult↗
PubMed1998

Transfusing platelets 2 h after the completion of amphotericin-B decreases its detrimental effect on transfused platelet recovery and survival.

Platelet transfusion support is required during bone marrow aplasia following ablative chemotherapy and bone marrow progenitor cell transplantation (BMT). Amphotericin-B is frequently given to these patients, both therapeutically and prophylactically, and has been described to have a negative impact on the results of platelet transfusions. We conducted a prospective study of the effect of amphotericin-B on transfused platelet recovery and survival in 81 BMT or acute leukaemia patients. One hundred and ninety-five platelet transfusions administered to 81 consecutive patients were analysed. The platelets were transfused 2 h after the completion of amphotericin-B. Using this schedule resulted in no effect of amphotericin-B on platelet recovery or survival, although platelet increments were modestly depressed in patients receiving high- vs. low-dose amphotericin-B. We conclude that the timing of amphotericin-B infusion be evaluated in patients demonstrating poor platelet recovery and survival. Transfusing platelets at least 2 h after the completion of amphotericin-B decreases the detrimental effect of this antifungal agent on transfused platelet recovery and survival.

Amphotericin B↗
PubMed1998

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome.

OBJECTIVES: To examine the proportions of type 1 and type 2 muscle fibres and the degree of muscle fibre atrophy and hypertrophy in patients with chronic fatigue syndrome in relation to lactate responses to exercise, and to determine to what extent any abnormalities found might be due to inactivity. METHODS: Quadriceps needle muscle biopsies were obtained from 105 patients with chronic fatigue syndrome and the proportions of type 1 and 2 fibres and fibre atrophy and hypertrophy factors were determined from histochemical preparations, using a semiautomated image analysis system. Forty one randomly selected biopsies were also examined by electron microscopy. Lactate responses to exercise were measured in the subanaerobic threshold exercise test (SATET). RESULTS: Inactivity would be expected to result in a shift to type 2 fibre predominance and fibre atrophy, but type 1 predominance (23%) was more common than type 2 predominance (3%), and fibre atrophy was found in only 10.4% of cases. Patients with increased lactate responses to exercise did have significantly fewer type 1 muscle fibres (p<0.043 males, p<0.0003 females), but there was no evidence that this group was less active than the patients with normal lactate responses. No significant ultrastructural abnormalities were found. CONCLUSION: Muscle histometry in patients with chronic fatigue syndrome generally did not show the changes expected as a result of inactivity. However, patients with abnormal lactate responses to exercise had a significantly lower proportion of mitochondria rich type 1 muscle fibres.

Adult↗
PubMed1998

"Pro-life" absolutes, feminist challenges: the fundamentalist narrative of Irish abortion law 1986-1992.

This article asks how Irish abortion law developed to the point of stopping a young pregnant rape victim from travelling abroad to have an abortion in 1992 (Attorney General v.X). The author argues that this case, which ultimately saw the Irish Supreme Court overturn that decision and recognize the young woman's right to abortion, was the last chapter of the fundamentalist narrative of Irish abortion law. The feminist critique of that law needs to consider its particular fundamentalist aspects in order to clarify the obstacles posed to the struggle for Irish women's reproductive freedom. The author argues that a fundamentalist narrative ordered the post-colonial and patriarchal conditions of Irish society so as to call for the legal recognition of an absolute right to life of the "unborn." The Supreme Court's interpretation of the constitutional right to life of the fetus in three cases during the 1980s is evidence that Irish abortion law was constructed through a fundamentalist narrative until that narrative was rejected in the Supreme Court decision in Attorney General v. X.

Adolescent↗
PubMed1997

A patch in the pectoral position lowers defibrillation threshold.

Implantable pacemaker cardioverter defibrillators are now available with biphasic waveforms, which have been shown to markedly improve defibrillation thresholds (DFTs). However, in a number of patients the DFT remains high. Also, DFT may increase after implantation, especially if antiarrhythmic drugs are added. We report on the use of a subcutaneous patch in the pectoral position in 15 patients receiving a transvenous defibrillator as a method of easily reducing the DFT. A 660-mm2 patch electrode was placed beneath the generator in a pocket created on the pectoral fascia. The energy required for defibrillation was lowered by 56% on average, and the system impedance was lowered by a mean of 25%. This maneuver allowed all patients to undergo a successful implant with adequate safety margin.

Defibrillators, Implantable↗