High dose rate brachytherapy--a starting up your own program.
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Brachytherapy↗
Biomedical subjects
G Powell
Publications and source records attributed to G Powell.
Is clozapine safe in the elderly?
OBJECTIVE: The aim of this paper is to assess the risk/benefit ratio of clozapine in the elderly. METHOD: MedLine and Internet searches, followed by cross-checking for further articles, identified the references. Reports on efficacy as well as side effects were examined. Five psychogeriatric patients treated by the authors are presented. RESULTS: The review of the literature highlighted the lack of studies on the use of clozapine in the elderly. Retrospective studies and case reports dominate. There is only one double-blind placebo-controlled study of six patients extant. Although efficacy seemed to parallel that in the younger age groups, the incidence of leukopenia, agranulocytosis, postural hypotension and confusion was greater in the elderly. Two of the five patients reported by the authors developed agranulocytosis, bringing the Australian experience of agranulocytosis in patients over 65 years of age to 4/55. CONCLUSION: The risk/benefit ratio in the elderly is distinctly higher than found in the younger population. With specific reference to agranulocytosis alone, the frequently quoted risk of 1% for patients is likely to be 5-10 times higher in the over 65 population. Caution is advised when prescribing clozapine in the psychogeriatric population.
Aged↗
Microchips versus stethoscopes, part 2: Revisiting OSCAR at the Foothills Hospital.
Several years have passed since the Foothills Hospital in Calgary installed a multi-million-dollar computerized patient-information system. When it arrived, the computer system known as OSCAR created controversy, anxiety and arguments among clinical caregivers who found it tedious, time consuming and cumbersome. Gregory Powell looks at how OSCAR has since changed the clinical landscape at Foothills.
Alberta↗
Photophobia and lithium.
CLINICAL PICTURE: We report the case of a 45 year old woman who developed photophobia after 6 months on lithium at non-toxic levels. TREATMENT AND OUTCOME: Lithium was reintroduced twice and on both occasions this side-effect reoccurred within days. CONCLUSIONS: Photophobia has only been described previously as a symptom of lithium intoxication.
Antimanic Agents↗
Personality and psychosocial function after brain injury.
A total of 74 brain-injured patients and 46 non-neurologically matched controls consecutively admitted to a specialist medical rehabilitation unit, were administered the 'Headley Court psychosocial rating scale' and four questionnaires examining personality traits of 'locus of control', 'use of humour', 'optimism' and 'easy-going disposition'. Both pre- and post-injury personality ratings were obtained. The relatives of all participants were sent the same scales. Personality changes are reported in each of the four areas; however, time post-injury appears to be a significant factor in the type of change reported; in this cross-sectional study, at 6 and 12 months post-injury, changes are noted in all variables except locus of control, whereas at 18 months post-injury only 'easy-going disposition' showed significant change, at 24 months post-injury changes were noted in all variables except optimism, and at 30 months post-injury no changes were noted. In the present study, examining a period of 2.5 years post-injury, the personality changes remain static once they have occurred. Despite widespread reports in the literature on the importance of pre- and post-trauma personality to good psychosocial functioning, the present study found that it was only an 'easy-going disposition' post-trauma that was consistently related to good psychosocial functioning. Reasons for this are discussed.
Adaptation, Psychological↗
Donor leg morbidity after pedicled rectus femoris muscle flap transfer for abdominal wall and pelvic reconstruction.
The pedicled rectus femoris muscle and myocutaneous flap has found application for a variety of soft tissue defects of the groin, pelvis, and lower abdomen. Although a number of authors have discussed the usefulness of this muscle flap, few have documented the morbidity from loss of this muscle in the leg. We have studied 7 patients who underwent unilateral rectus femoris muscle transfer, comparing strength of the donor knee to the normal knee. All patients were studied using a computerized dynamometer for strength of knee flexion and contraction. We found that loss of the rectus femoris in patients not undergoing a postoperative program of therapy led to an average decrease in strength about the knee of 24% to 28%, depending on the motion measured. A single patient who underwent an intensive postoperative therapy program had return of normal strength in his donor leg. Despite this common loss of strength, patient complaints were few and the results of reconstruction appeared to outweigh this loss of strength.
Abdominal Muscles↗
What events precede violent incidents in psychiatric hospitals?
BACKGROUND: The study aimed to identify, classify and measure the relative frequency of events preceding violent incidents in psychiatric hospitals. METHOD: Possible antecedents for 1000 incidents in three associated psychiatric hospitals over 13 months were investigated with an 'untoward incident database'. RESULTS: From eyewitness accounts, 921 incidents (92%) could be related to one of 15 categories of antecedent involving characteristics of the patient, or of the hospital regime, or interactions with other individuals. Overall, the most common antecedents involved patients who were generally agitated or disturbed (286), restrictions on patients associated with the routine hospital regime (192) or provocation by other patients, relatives or visitors (175). Incidents arising from staff members initiating contact with patients were very rare (7). Twenty-one patients were involved in 10 or more incidents, including 19 (90%) who were detained under the Mental Health Act. These patients were more likely to commit assaults after certain antecedents (self-harm, absconding or arson) which were serious incidents in themselves. CONCLUSIONS: Staff training on specific safety issues will be needed under the new Management of Health and Safety at Work Regulations.
Adult↗
Parathyroid hormone-related protein in human term placenta and membranes.
Parathyroid hormone-related protein (PTHrP), the hypercalcaemia of malignancy factor, is expressed in the tissues of the human uteroplacental unit, including the placenta, amnion and chorion. We have used three region-specific immunoassays to quantitate and compare the distribution of PTHrP in tissues obtained at term following spontaneous labour and vaginal delivery or elective Caesarean section. In non-labouring women highest PTHrP(1-86) and (37-67) immunoreactivity was found in amnion covering the placenta, rather than the decidua parietalis of the uterus (reflected amnion) (median 1020 vs 451 fmol/g; 2181 vs 1444 fmol/g respectively). In labouring women, the PTHrP(1-86) concentration in reflected amnion was inversely correlated with the interval between rupture of the membranes and delivery. Tissue PTHrP(1-86) concentrations were lower in placenta than in chorion and amnion (medians 12, 109 and 664 fmol/g respectively) and, in all tissues, PTHrP(1-34) and (37-67) concentrations were significantly higher than that of PTHrP(1-86). Bioactive PTHrP(1-34) was detected in placenta, chorion and amnion using the ROS cell bioassay. The PTHrP(1-86) concentration (mean +/- S.E.M. = 41.4 +/- 4.5 pmol/l) was high in amniotic fluid at term, although in maternal and cord plasma levels were only modestly increased. The molecular forms of PTHrP present in tissues and amniotic fluid were investigated by column chromatography which confirmed its molecular heterogeneity and suggested that processing is tissue-specific and occurs at both amino- and carboxy-terminals of the peptide.
Amnion↗
Use of benzodiazepines in anxiety disorders.
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Anti-Anxiety Agents↗
Combined effects of laser irradiation and chemical inhibitors on the dissolution of dental enamel.
It has previously been shown that the susceptibility of human teeth to acid dissolution can be reduced by the presence of various chemical agents in the dissolution medium or by pretreatment of the teeth with laser irradiation. Now synergism between these two approaches to improving acid resistance has been demonstrated. Extracted human teeth were irradiated with a continuous-wave carbon dioxide laser at a wavelength of 10.6 microns. Energy doses of either 65 or 130 J/cm2 given over periods of 2 or 4 s, respectively, were applied and the teeth subjected to a severe acid challenge (0.1 M acetate buffer, pH 4.5, no calcium or phosphate common ion present) for 24 h. Mineral loss was assessed by measurement of mineral density profiles with quantitative microradiography. Experiments were carried out in the presence or absence of three chemical inhibitors with distinctly different mechanisms of action: ethane-1-hydroxy-1, 1-diphosphonic acid, fluoride, and dodecylamine HCl. Laser irradiation alone was found to lead to increased resistance of the teeth to acid challenge, with the higher energy dose being more effective than the lower dose. Each of the chemical inhibitors was effective on both lased and unlased teeth, with the percent reduction of dissolution greater when the inhibitors were applied to teeth lased with an energy dose of 130 J/cm2 which were already more resistant to acid challenge than were unlased teeth or teeth lased with a dose of 65 J/cm2.(ABSTRACT TRUNCATED AT 250 WORDS)
Absorptiometry, Photon↗
Level of medical care required for mass gatherings: the XV Winter Olympic Games in Calgary, Canada.
STUDY OBJECTIVE: To determine the level of medical care required for mass gatherings and describe the types of medical problems encountered in a major winter event. DESIGN: Standard charts were available for 3,395 encounters. Interviews with medical staff showed that the few unrecorded encounters were for very minor medical problems. A four-tiered triage system (low, moderate, urgent, and emergent) developed before the Games was applied to each chart retrospectively by a single emergency physician. Chi-squared tests were used to test significant differences. SETTING: This winter sporting and entertainment event had 12 urban and rural venues. Medical staff (98 physicians, 161 nurses, and 337 first-aid attendants) were based in 28 advanced life support (ALS) clinics. The medical service operated for four weeks. TYPE OF PARTICIPANTS: There were 1.8 million spectator-days. Patients included spectators, athletes, and support staff. INTERVENTIONS: First-aid attendants referred patients to the clinics, where nurses conducted initial assessments and referred patients to physicians at the venue, or more rarely, to local hospital emergency departments. Paramedic ambulances were stationed at the venues. The triage system was not used for patient management. MEASUREMENTS AND MAIN RESULTS: Only 40 urgent and one emergent medical problems were encountered. The majority of patients could have been managed by trained nurses working alone under standing orders. Fifty patients were transported to the hospital by ground ambulance and three by helicopter. No significant differences were found in the low acuity levels experienced at indoor urban venues, outdoor urban venues, and the rural cross-country ski venue. The Alpine ski venue was characterized by significantly higher acuity and a long prehospital transfer phase. CONCLUSION: Owing to the low acuity encountered and the availability of Calgary's ALS ambulance service, we concluded that physician-based ALS teams were not required for patient management at the urban venues. Such teams were found to be required at the rural Alpine ski venue. Other reasons for using physicians are discussed, as is development of a standard triage system for mass gatherings.
Alberta↗
Cerebral activity prior to motion task performance: an electroencephalographic study.
Cerebral activity, as reflected by power in the alpha waveband (8-13 Hz), was examined prior to the performance of three tasks with different effort and accuracy requirements. The study aimed to further investigate changes in activity observed in an earlier study in which expert karate performers exhibited significant increases in alpha band power during preparation for a training task. In contrast to the earlier research, the high effort task produced a significant decrease in 'alpha' power prior to performance. 'Alpha' power prior to the high accuracy task showed significant differences mediated by the outcome. Successful performance was preceded by higher levels of 'alpha' power than unsuccessful attempts. The reported use of a cognitive strategy on the first task produced a significant difference in activity, lower alpha power being associated with the use of such a technique.
Attention↗
Effect of functional appliances on jaw muscle activity.
The electromyographic (EMG) activity of masticatory muscles was monitored longitudinally with chronically implanted EMG electrodes to determine whether functional appliances produce a change in postural EMG activity of the muscles. Preappliance and postappliance EMG levels in four experimentals that had been fitted with functional appliances were compared against the background of EMG levels in controls without appliances. The insertion of two types of functional appliance to induce mandibular protrusion was associated with a decrease in postural EMG activity of the superior and inferior heads of the lateral pterygoid, superficial masseter, and anterior digastric muscles; the decrease in the first three muscles was statistically significant. This decreased postural EMG activity persisted for approximately 6 weeks, with a gradual return toward preappliance levels during a subsequent 6-week period of observation. Progressive mandibular advancement of 1.5 to 2 mm every 10 to 15 days did not prevent the decrease in postural EMG activity.
Activator Appliances↗
Fluconazole success after amphotericin B and flucytosine failure in cryptococcal meningitis.
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Adult↗
Allergy to laboratory animals: a prospective and cross-sectional study.
Allergies among animal handlers to their subjects is a problem of high prevalence and relatively low morbidity but with often serious career implications. This study sought to determine whether historical factors, such as general allergic symptoms and atopic indicators, could be used to predict which animal handlers would be affected with allergies to laboratory animals (ALA). In a prospective study, 169 laboratory workers with animal exposure were surveyed by questionnaire for these factors in 1985 and again 2 years later. The presence of three general allergic symptoms (relative risk = 4.29) and three historical atopic indicators (relative risk = 2.50) were moderately predictive of the new onset of ALA. This suggests that those animals handlers with allergic histories are at greater risk of developing ALA, although this is a relatively nonspecific marker. In a concurrent prevalence study, the measurement of airborne rat urinary protein was significantly associated with the presence of ALA (prevalence ratio = 1.75). The measurement of airborne allergens could be helpful in monitoring the effectiveness of air handling equipment with the ultimate goal of reducing the incidence of ALA.
Animals↗
Fibrous hamartoma of infancy: a histochemical and immunohistochemical study.
Fibrous hamartoma of infancy is an uncommon lesion, the histogenesis and biological nature of which are uncertain. Ten cases have been studied by light microscopy, mucin histochemistry and immunohistochemistry. The typical histological features are presented. The presence of hyaluronic acid and of chondroitin-4- and -6-sulphate and keratan sulphate has been demonstrated in different components of the tumour. Vimentin positivity was noted in the undifferentiated and fibroblastic components. The implications of these findings are discussed. Whether the lesion merits the designation of hamartoma or is, in fact, a benign neoplasm remains obscure.
Child↗
Pigmented neuroectodermal tumour of infancy: an immunohistochemical study.
The pigmented neuroectodermal tumour of infancy is a rare neoplasm of uncertain histogenesis which, in the majority of cases, arises in the maxilla and pursues a benign course. Currently, it would be classified in the group of peripheral primitive neuroectodermal tumours. Histologically it is composed of two principal cell types: neuroblast-like and melanocyte-like. Three typical cases are presented herein, which appear to be the first examined with a panel of antibodies. The neuroblast-like cells labelled positively for neurone-specific enolase but were negative for S-100, neurofilaments, glial fibrillary acidic protein, vimentin, cytokeratin, epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA). The melanocyte-like cells stained positively for neurone-specific enolase, vimentin and cytokeratin but were negative for S-100, neurofilaments, glial fibrillary acidic protein, EMA and CEA. The significance of these findings is discussed in the light of previous suggestions about the differentiation that these tumours show.
Cell Differentiation↗