Dosimetric Parameters in Partial Breast Irradiation Through Brachytherapy

The objective of this work is to evaluate biological models and dose homogeneity in a new partial breast irradiation method, the MammoSite RTS. The study is based on 11 patients who received the therapy. For each patient, we determined the dose volume distribution delivered to the breast. Based on these data, we estimate some important biological parameters. Eleven patients with early-stage, invasive, ductal breast cancer were treated using MammoSite RTS brachytherapy, which delivers radiation through a balloon placed in the lumpectomy bed. The radiation was provided by an Iridium-192 source, and 340 cGy were delivered per fraction twice daily. We calculated some commonly used dosimetric parameters, and evaluated the biological parameters tumor control probability (TCP) and normal tissue complication probability (NTCP). We also looked for correlations among these parameters. The average equivalent uniform dose (EUD), NTCP, and TCP were 43.66 Gy, 47.95%, and 91.78%, respectively. The coefficient of variation (CV) among the patients was very low for all 3 parameters. Two dose homogeneity indices (DHI and the S-index) are strongly correlated (r = −0.815). The area under the dose-volume histogram (DVH) and the treatment volume (TXV) also showed a strong correlation (r = 0.995, p < 0.0001). A simplified logit Poisson–EUD model is suitable for determining NTCP and TCP. Other factors such as the area under the DVH and dose homogeneity indices are also useful in planning radiotherapy treatments for early breast cancer.     

The effect of infusions of adrenaline,noradrenaline and dopamine on cerebral autoregulation under propofol anaesthesia in an ovine model

OBJECTIVE: To compare the effects of infusions of adrenaline, noradrenaline and dopamine on cerebral autoregulation under steady-state propofol anaesthesia with the awake state. DESIGN: Prospective, randomised, interventional animal study. SETTING: University laboratory. SUBJECTS: Six studies in two cohorts of adult ewes: awake and steady-state propofol anaesthesia (15 mg/min). INTERVENTIONS: In random order, each animal received ramped infusions of adrenaline, noradrenaline (0-40 microg/min) and dopamine (0-40 microg/kg per min). MEASUREMENTS AND RESULTS: Cerebral blood flow (CBF) was measured continuously from changes in Doppler velocities in the sagittal sinus and normalised to a PaCO(2) 35 mmHg. Propofol decreased CBF by 55% relative to pre-anaesthesia values (p=0.0001). All three catecholamines significantly and equivalently increased mean arterial pressure (MAP) from baseline in a dose-dependent manner in both awake and propofol cohorts. Adrenaline significantly increased CBF from baseline in both awake sheep (p<0.01) and during propofol anaesthesia (p<0.001); noradrenaline and dopamine did not statistically increase CBF. When comparing the effects of individual catecholamines with each other within each cohort, no statistically significant difference between the catecholamines was demonstrated. (p>0.05). Using linear regression analysis, normalised CBF was correlated against associated changes in MAP. No significant differences were demonstrated between the slopes of regression lines for adrenaline, noradrenaline and dopamine in either cohort (ANCOVA). There was a statistically significant difference between the intercepts of the awake and propofol cohorts (p<0.0001), but no difference between the slopes (p=0.69). CONCLUSIONS: Over a specific dose range, catecholamine-induced hypertension caused increased CBF during steady-state propofol anaesthesia. This effect was offset by an associated reduction in CBF caused by propofol. The concomitant administration of propofol and catecholamines was not associated with altered autoregulatory function compared to the awake state.     

Neonatal intensive care nurses’ perceptions of implementing parent discharge preparation tools

BackgroundStandardized tools for discharge education can facilitate transitions from the neonatal intensive care unit to home. Perceptions of nurses regarding parental discharge preparation and relevant tools can inform implementation.PurposeTo describe nurses’ perceptions of discharge preparedness and implementation of a standardized tool to facilitate nurse-parent engagement in discharge education.MethodsWe conducted semi-structured interviews with seven nurses meeting eligibility criteria. Interviews were conducted using an interview guide developed for this study and were audio-recorded, transcribed verbatim, and thematically analyzed.ResultsThree major themes emerged: 1) Discharge Education is an Ongoing and Evolving Process; 2) Nurse-Parent Partnerships; and 3) Importance of Context to Implementation of Standardized Tools. Sub-themes emerged from the data to support each major theme.ConclusionStandardized tools can improve parent discharge preparedness and implementation of these tools is facilitated by well-described processes, partnerships between nurses and parents, and tailoring to the unit context.     

Botulinum toxin A versus bupivacaine trigger point injections for the treatment of myofascial pain syndrome: a randomised double blind crossover study

The treatment of myofascial pain syndrome (MPS) is diverse and includes trigger point injections of various substances including local anesthetics, steroids and Botulinum toxin A (BTX A). The purpose of this study was to compare the effectiveness of trigger point injections using BTX A versus bupivacaine, both in combination with a home-based rehabilitation program. To be enrolled, subjects first had to demonstrate responsiveness to bupivacaine trigger point injection. In this single center, double blind, randomized, cross-over trial, 18 patients with MPS received trigger point injections of either 25 units Botulinum toxin A or 0.5 ml of 0.5% bupivacaine per trigger point. A maximum of eight trigger points were injected per subject. Subjects were followed until their pain returned to 75% or more of their pre-injection pain for two consecutive weeks, after which there was a 2 week wash-out period. The subjects then crossed over and had the same trigger points injected with the other agent. All subjects participated in a home exercise program involving static stretches of the affected muscles. Both treatments were effective in reducing pain when compared to baseline (P=0.0067). There was, however, no significant difference between the BTX A and 0.5% bupivacaine groups in duration or magnitude of pain relief, function, satisfaction or cost of care (cost of injectate excluded). Considering the high cost of BTX A, bupivacaine is deemed a more cost-effective injectate for MPS.     

Estrogen receptor beta dominates in baboon carotid after endothelial denudation injury

Increasing evidence, mainly from rodents, suggests that the predominant estrogen receptor (ER) in arteries is the newly-described ERbeta. We have investigated the expression of the two ERs in baboon carotid artery before and after denudation injury. Prior to denudation, both full length receptors were detected in semiquantitative RT-PCR; in addition two ERalpha but no ERbeta splicing variants were found. After denudation, ERbeta mRNA increased five-fold and declined, whereas ERalpha mRNA expression remained low. Prior to and after denudation, two ERalpha-specific antibodies showed no reaction with the vessel wall. Instead, two affinity purified antisera to ERbeta demonstrated a weak but distinct reaction over vascular smooth muscle cells with predenudation specimens, escalating post-denudation and declining thereafter. The results suggest that selective targeting to ERbeta should be attempted when designing estrogen-based vasculoprotective drug therapies devoid of uterotrophic side effects.     

Oral propafenone in the suppression of chronic stable ventricular arrhythmias

The efficacy of propafenone hydrochloride, a new antiarrhythmic agent, was evaluated in the treatment of chronic stable ventricular arrhythmias. Twenty-five patients who had suffered a myocardial infarction three months or longer before the trial were studied. All exhibited a minimum mean frequency of 30 ventricular ectopic beats per hour over at least two 24-hour Holter monitoring periods with the last recorded tape serving as a control. The mean decrease in ventricular ectopic activity with propafenone was 65.62 percent (p = less than 0.001). Side effects were infrequent, minimal, and of no clinical consequence. Oral propafenone was found to be an effective drug for reducing the level of chronic ventricular ectopy, as reflected by a short-term trial.     

Acute tissue-type plasminogen activator release in human microvascular endothelial cells: the roles of Galphaq, PLC-beta, IP3 and 5,6-epoxyeicosatrienoic acid

The acute physiologic release of tissue-type plasminogen activator (t-PA) from the endothelium is critical for vascular homeostasis. This process is prostacyclin- and nitric oxide (NO)-independent in humans. It has been suggested that calcium signaling and endothelial-derived hyperpolarizing factors (EDHF) may play a role in t-PA release. G-protein-coupled receptor-dependent calcium signaling is typically Galphaq-dependent. EDHFs have been functionally defined and in various tissues are believed to be various regioisomers of the epoxyeicosatrienoic acids (EETs). We tested the hypothesis in vitro that thrombin-stimulated t-PA release from human microvascular endothelial cells (HMECs) is both Galphaq- and EDHF-dependent. Conditioned media was harvested following thrombin stimulation, and t-PA antigen was measured by ELISA. Thrombin-induced t-PA release was limited by a membrane-permeable Galphaq inhibitory peptide, the PLC-beta antagonist U73122, and the IP3 receptor antagonist 2-aminoethoxyphenylborane, while the Galphaq agonist Pasteurella toxin modestly induced t-PA release. The cytochrome P450 (CYP450) inhibitor, miconazole, and the arachidonic acid epoxygenase inhibitor MS-PPOH inhibited thrombin-stimulated t-PA release, while 5,6-EET-methyl ester stimulated t-PA release. The 5,6- and 14,15-EET antagonist, 14,15-epoxyeicosa-5(Z)-enoic acid, inhibited t-PA release at the 100 microM concentration. However, thrombin-stimulated t-PA release was unaffected by the prostacyclin and NO inhibitors ASA and L-NAME, as well as the potassium channel inhibitors TEA, apamin and charybdotoxin. These studies suggest that thrombin-stimulated t-PA release is Galphaq-, PLC-beta-, IP3-, and 5,6-EET-dependent while being prostacyclin-, NO- and K+ channel-independent in HMECs.     

The relation between illness cognitions and quality of life in people with and without a stoma following rectal cancer treatment

Objectives: To compare health‐related quality of life, emotional functioning and illness cognitions between people with and without a stoma after rectal cancer treatment about 8 years ago and to examine the relation between illness cognitions and health‐related quality of life and emotional functioning. Methods: Sixty‐two people who had undergone abdominoperineal resection with a permanent stoma and 60 people who had undergone low anterior resection without a permanent stoma participated. Questionnaires included the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire—C30, the Hospital Anxiety and Depression Scale, and the Illness Cognition Questionnaire. Results: There were no significant differences between people with and without a stoma in health‐related quality of life, emotional functioning and illness cognitions. There were moderate and significant relations between the illness cognitions helplessness (negative) and disease acceptance (positive) on the one hand and health‐related quality of life and emotional functioning on the other. For helplessness this relation barely differed between people with and without a stoma, but for disease acceptance this relation was stronger for people without a stoma than for people with a stoma. Conclusions: The study showed no differences in health‐related quality of life, but a stronger relation between disease acceptance and health‐related quality of life for people without a stoma than for people with a stoma. If this relation is causal, people with negative illness cognitions after rectal cancer treatment might be identified and offered help. Copyright © 2010 John Wiley & Sons, Ltd.